* GB786144 (A)

Description: GB786144 (A) ? 1957-11-13

Thermoplastic compositions having improved light stability

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COMPLETE SPECIFICATION Thermoplastic Compositions having improved Light Stability We, THE DOW CHEMICAL COMPANY, a Corporation organized and existing under the Laws lof the State of Delaware, United States of America, of Midland, Ciounty of Midland, State of Michigan, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to, be performed, to be particularly described in sand by the fol- lowing statement: This invention relates to new and improved thermoplastic compositions. More particularly it relates to polymeric compositions having improved stability to the degradaltive effects of sunlight. Thermoplastic compositions, particularly those prepared from haloethylene polymers, have found wide acceptance as useful materials for making foils, fibres, filaments, and other articles. The articles so produced are inherently strong, dimensionally stable, reSa- tively inert to common household solvents, and are early coloured for an attractive appearance. However, such articles are subelect to rapid and severe degradation and consequent discoloration due to the effects of heat and light. The problem becomes most serious when polymeric compositions are empioyed las filamentary materials in making window

curtains, automobile seat covers, and other articles which are exposed for prolonged periods of time to direct sunlight. To civer- come this disadvantage it has become most practical to incorporate certain additives into the composition to stabilize it to the effects of heat and to add other materials to the composition to stabilize it to the effects of light. Some d the prior light stabilizing materials h!ave suffered from the disadvantages of bleeding out of articles made from vinyl or vinylidene halides. In addition, some of the materials are coloured so that they impart an objectionable initial colour which prevents the production of white articles. Further, many of the prior materials lose their effectiveness as light stabilizers after exposure to sunlight for a short time. It is accordingly an object of this invention to provide improved polymeric compositions having increased resistance to the degradative effects of light It is a further object to provide such a composition which is based on a chlloroethylene polymer and is resistant to the effects of light over prolonged - periods of exposure to direct sunlight. According to the present invention there is provided a light stable composition comprising an organic thermoplastic material normally subject to discoloration on exposure to light and from 0.1 to 10 per cent. of the weight of said thermoplastic of a dibenzoyl resorcinol compound as a stabilizer having the general formula: <img class="EMIRef" id="026598829-00010001" /> wherein R1 to R,, inclusive, are selected from H, Cl, Br, F, an alkyl group having from 1 to 8 carbon atoms, and POOR7 wherein R, is selected from an alkyl group having from 1 to 8 carbon atoms, phenyl, monochllorophenyl, monobromophenylrand monow alkylphenyl, and RG is selected from R1, benzoyl, and benzoyl substituted with R1 and R2; there being not more than 4 bromine atoms, not more than 3 fluorine atoms, not more than 3 -CO OR7 groups in the compound, and not more than one -CO OR7 group attached to any benzene ring. The compositions of this invention show effective resistance to the degradative effects of light -even after prolonged exposure. Among the specific compounds defined by the foregoing formula and which have light stabilizing action in thermoplastic compositions are: 2)4-dibenzoyl! resorcinol 4,6-dibenzoyl resorcinol 2,4-dibenzoyl, 6-chlororesoranol 2.,4-dibenzoyl, 6-hexyiresorcinol 2,4-di(4-chlorob enzoyl)resorcinol 2,4-di(4-bromobenzoyl)resoranol 2,4-di(4-fiuorohenzoyl)resorcinol 2,4-di(2,4-dichlorobenzoyl)resorcinol 2 > 4-di(2A-dibromobenzoyi)resorcinol 2,4-di(2,4,6-trichlorobenzoyl)resorcinol

2,4di(4-methylbenzoyl)resorcinol 2,4-di(4-butylbenzoyl)resorcinol 3,5-dibenzoyl, 2,4-dihydroxybenzoic acid, methyl ester 3,5-dib enzoyl, 2,4-dihydroxybenzoic acid, butyl ester. 3,5-dibenzoyl, 2,4-dihydroxybenzoic acid, 2 ethylhexyl ester 3,5-dibenzoyl, 2,4 - dihydroxybenzoic acid, phenyl ester 3,5-dibenzoyl, 2,4-dihydroxybenzoic acid, 4 chlorophenyl ester 3,5-dibenzoyl, 2,4-dihydroxybenzoic acid, 4 bromophenyl ester 2,4di(monomethylphthaloyl)resorcinol 3,5di(monomethylphthaloyi), 2,4-dihydroxy benzoic acid., methyl ester. The polymers which may be employed in the compositions of this invention may be selected from a wide variety of polymers, such as polystyrene, polyethylene, and cellulosic esters and ethers. However, especially advantageous results are obtained when haloethylene pdlymers, such as the polymers of vinyl chloride, copolymers of vinyl chloride and vinylidee chloride, and copolymers of vinylidene chloride with other copolymerizable monomers in which the vinylidene chloride is present in an amount of at least 50 per cent. of the copolymer are employed, and such polymers are preferred in preparing the oom- positions. The baloethylene polymers present an unusual problem in that once degradation has started the effect seems to be autocatalytic, and thus the problem of stabilization is made more difficult Dibenzoyl resorcinol may be easily prepared from readily available materials by a number of known methods. One such method consists of subjecting an orthodichioroben- zene solution of resorcinol benzoyl chloride, and a slight excess aluminium chloride to a temperature of 135 C. for one-half hour after which' dilute HO is padded to the reaction mixture. The product may be purified by distillation or by recrystailization from methanol or by both processes. When produced by this method the product is found to consist substantially of from 75 to 90 per cent. of the 2,4-dibenzoyl resorcinol isomer and from 10 to 25 per cent. of the 4,6-dibenzoyl resorcinol derivative. Such mixtures present no problem, however, since the mixture has been found to be equivalent to either of the two isomers in light stabilizing effectiveness. The substituted derivatives of dibenzoyl resorcinol may be prepared by using the correspondingly substituted resorcinol or benzoyl chloride as starring materials. The dibenzoyl resorcinol derivatives may be employed in amounts of from 0.1 to 10 per cent. by weight based on the weight of the polymer, preferably from 0.25 to 3 per cent. by weight. Most pclymeric compositions comprise many ingredients such as plasticizers, fillers, pigments, and heat stabilizers, and the derivatives of this invention

may be employed in the compositions in conjunction with such additives without any adverse effects. Likewise, the dibenzoyl resorcinol derivatives of this invention may be used in conjunction with other known light stabilizers. When so used, the dibenzoyl resorcinol derivative enhances the light stabilizing effectiveness of the known stabilizer to a surprising degree. The ingredients may be intermixed by milling or blending by known conventional methods. The compositions of this invention show superior resistance to degradation due to light over any previously known compositions Following is a description by way of example of methods of canying the invention into effect. In the examples all parts are parts by weight EXAMPLE 1. A series of three samples were made consisting of 90 parts of a copolymer prepared from a monomeric mixture consisting of 85 per cent. vinylidene chloride and 15 per cent. vinyl chloride, 7 parts of acetyl triethyl dt- rate as plasticizer and one part of tetra- sodium pyrophosphate as a heat stabilizer. To one of the samples was added 2 parts of 2hydroxy 5-chiorobenophenone, a known light stabilizer. The second sample had no light stabilizer added, and ro the third sample was added 1 part of a mixture of 2,4- and 4,6dibenzoyl resorcinol isomers. Each sample was moulded into a sheet 0.01 inch thick. All of the sheets were then exposed to direct sunlight in the State of Florida for 3 months. After exposure the sheets were examined visually snd rated for colour according to an arbitrary scale in which 0 means no colour, 5= yellow; 10= tan; and 20=black. The results of this test are given in Table I. TABLE I. Original Colour after Numerical Stabilizer colour exposure rating None colourless very dark brown 17 2-Hydroxy 5-chloro- light benzophenone yellow tan 10 Dibenzoyl resorcinol colourless slight yellowing 4 From the results it can be seen that dibenzoyl resorcinol is far better as a light stabilizer for vinylidene chloride copolymers than is 2-hydroxy 5-chlorobenzophenone which is a commercially accepted light stabilizer. In addition the dibenzoyl resorcinol does not impart an initial yellow colour to the polymer as did the other stabilizer. EXAMPLE 2. Samples were prepared to check the effectiveness lof various substituent groups on 'the light stabilizing effectiveness of subs'tl- tured dibenzoyl resorcinols. The formulation consisred of 100 parts of polyvinyl chloride, 50 parts of dioctyl plithalate, 3 parts of known organo-metallic heat stabilizers, 0.1 part of stearic acid as a lubricant, and 1 part of the new light stabilizer. The samples were

prepared by milling on a two roll mill, after which they were moulded into sheets having a thickness of 0.025 inch. The original colour of the sheet was noted and the samples were then lexposed to the radiation of a sunlamp for 35, 53 and 93 days which corresponds respectively to 500, 1000 and 2000 ultra-violet sun hours. The samples were examined after each period of exposure and the amount of colour change from the original colour rated according to an arbitrary scale. In this scale a rating of 0 means no change, 5 indicates yellowing, 10 indicates Tan, and 20 indicates a black colour. (When the samples had an original colour which disappeared or was reduced on exposure [a minus sign indicates the amount of bleaching that occurred. The higher the numerical value the greater was the bleaching). The results are tabulated in Table II. TABLE II Colour Rating After Time in Days Stabilizer Original Colour 35 53 93 None 7 17 20 Salol Slightly yellow 2 4 6* 2-Hydroxy 5-chloro benzophenone do. 0 4+ 20 Monobenzoyl resorcinol do. -1 -1 0 Tribenzoyl resorcinol do. -2 -2 -2 2,4-Dibenzoyl resorcinol do. -4 -4 -4 4,6-Dibenzoyl resorcinol do. -6 -6 -6 Di(4-chlorobenzoyl) resorcinol do. -5 -5 -5 Di(2,4-dichiorobenzoyl)- resorcinol Yellow -6 -6 -6 * dark spots + tacky surface From the tabulated results it can be seen that the new stabilizers give better protection than known light stabilizers and better than the closely related monobenzoyl resorcinol. EXAMPLE 3. The light stabilizing etiectiveness of di- benzoyl resorcinol in polystyrene was tested by thoroughly intermixing polystyrene with 1 per cent. of its weight of dibenzoyl resorcinol. Sheets were moulded from both the stabilized composition and polystyrene alone. The samples were checked for colour by measuring the amount of transmittancy of light 6200at minus the amount of transmittancy of light of 4200A". After exposure to direct sunlight in the State of Florida for three months ithe colour Was again measured. The results are tabulated in Table Ill. TABLE III. Transmlittancy 1% Change in

Stabilizer Original After 3 Months Transmittancy None 2.1 20.9 18.s Dibenzoyl resorcinol 23.9 27.7 3.8 The results indicate that the sample having no stabilizer had greater than an 18 per cent darkening in colour while the sample stabilized with dibenzoyl resorcinol had less than 4 per cent. darkening. EXAMPLE 4. Samples were prepared to test the compatibility and the effectiveness of mixtures of light stabilizers. The samples were prepared as ain Example 2 except that the formulation consisted of 89 parts of a copolymer prepared from 85 per cent. vinylidene chloride and 15 per cent vinyl chloride, 0.5 part of sodium tripolyphosphate, 0.5 part of disodium lauryl phosphate, 5 per cent. Hercofiex 600 as plasticizer, and a total of 5 per cent of the indicasted light stabilizers. The samples were exposed in the State of Florida for 3000 ultraviolet sun hours. They were checked periodically for amount of colour change and the potentisily useful life of the formulation talon to be the time required to reach a yellow colour. These results are listed in Table IV. TABLE IV Useful Life (Ultra-Violet 1st Stabilizer % 2nd Stabilizer % Sun Hours) 2-Chloro-5-hydroxy benzophenone 3.0 - - 500 Dibenzoyl resorcinol 3.0 - - > 1500 2-Chloro-5-hydroxy benzophenone 2.0 Salol 3.0 440 2-Chloro-5-hydroxy benzophenone 2.0 Dibenzoyl 3.0 > 1000 resordnol It can be seen that the mixtures contain ing dibenzoyl resorcinol are better than twice as stable to light us the mixtures containing the salol. Such an increase is of great significance when polymeric products are fabricated into articles which may be exposed to sun light for prolonged periods. ExAMPLE 5. A series of samples was prepared to check the effectiveness of the dibenzoyl resorcinol deprivatives when used in compositions together with different plasticizers some of which could not be used previously due to resulting instability of the plasticized compositions. The basic formulation consisted of 91 parts of a copolymer prepared from a monomeric mix ture consisting of 85 pet cent. vinylidene chloride and 15 per cent vinyl chloride, 0.5 part of sodium tripolyphosphate and 0.5 part

of sodium laurel phoshate as heat stabilizers, 3 parts of a mixture of 2,4- and 4,6dibenzoyl resorcinol, and 5 parts of the plasticizer. By nvay of comparison a second series of samples was prepared identical to the first except that 3 parts of 2-hydroxy 5-chlorobenzophenone were employed in place of the mixture of dibenzoyl resorcinol isomers. All of the samples were mixed by milling on a two roll mill and then compression moulded into test strips. The test strips were exposed to direct sunlight in the State of Arizona for 1000 ultra-violet sun hours. The strips were examined periodically for discoloration and the potential useful life of each composition taken as the number of ultraviolet sun hours needed to reach a yellow discoloration. These results may be found in Table V. TABLE V. Useful Life (Ultra-violet Sun Hours) 2-Hydroxy, Dibenzoyl 5-Chloro Plasticize Resorcinol benzophenone Acryl trioctyl citrate > 1000 400 Pentaeethritoi tetraester of a mixture of > 1000 325 saturated fatty acids (av. chain length=CO) Polyester of propylene glycol and adipic and > 1000 375 lauric acids Polyester of propylene glycol and sebacic 540 275 acid Chlorinated diphenyl (68% Gl) 420 275 Chlorinated terphenyl (42% Cl) 310 200 The results show that the useful life of the articles can be extended from 1.5 to 3 times as long as that of similar articles made of previously known compositions. Thus, where some plasticizers could not ba employed in the past because of the instability of the plasricized compositions to light, those sate plasticizers may now be used in producing stable compositions. The dibenzoyl resorcinols and their defined substitution products are useful light stabilizers for all thermoplastic compositions which are normally subject to discoloration due to ultraviolet radiation. Thus, in addition to the polystyrene, polyvinyl chloride, and vinyl chloride-vinylidene chloride copolymers of the examples, these agents exhibit their protective effect when incorporated in cellulose acetate, ethyl cellulose, polyacrylonitrile, and other thermoplastic film- or fibre-forming compositions What we claim is: - 1. A light stable composition comprising an organic thermoplastic matcrial normally subject to discoloration lon exposure to light and from 0.1 to 10 per cent. of the weight of said thermoplastic of a

dibenzoyl resorcinol compound as a stabilizer having the general formula: <img class="EMIRef" id="026598829-00050001" /> wherein R1 to Rn, inclusive, are selected from H, C1, Br, F, an alkyl group having from 1 to 8 carbon atoms, und -COOR7 wherein R, is selected from an alkyl group having from 1 to 8 carbon atoms, phenyl, n onochlloro- phenyl, monobromophenyl and monoalkyl- phenyl, and R6 is selected from R1, benzoyl, and benzoyl substituted with R1 and R, there being not more Ithan 4 bromine atoms, not more than 3 fluorine atoms nor more than 3 -CO OR, groups in the compound, and not more than one -CO OR group attached to any benzene ring. 2. The composition claimed in claim 1 wherein the derivative of dibenzoyl resorcinol is present in an amount of from 0.25 to 3 per cent. by weight 3. The composition claimed in claim 1 wherein the stabilizer is a mixture of 2,4-dibenzoyl resorcinol and 4,6-dibenzoyl resorcinol. 4. The composition claimed in claim 1 wherein the thermoplastic material is polyvinyl chloride. 5. The composition claimed in claim 1 wherein the thennopilastic material is a Co- polynter of vinylidene chloride and vinyl chloride. 6. The composition claimed in claim i wherein the thermoplastic material is a Co- polymer of at least 50 per cent vinylidene chloride and another polymerizable monomer. 7. A composition comprising a predominantly vinylidene chloride copolymer and from 0.1 to 10 per cent,. based on the weight of the copolymer of dibenzoyl resorcinol. 8. A composition comprising a predomin- antly vinylidene chloride copolymer and from 0.1 to 10 per cent based on the weight of the copolymer of di-(2-chlorobenzoyl)-resorcinol. 9. A composition comprising a predomingently vinylidene chloride copolymer and from 0.1 to 10 per cent based on the weight of the copolymer of di-(4-chlorobenzoyl) - resorcinol. 10. A composition comprising a predominantly vinylidene chloride copolymer and from 0.1 to 10 per onit, based on the weight of the copolymer, of di-(2,4dichloro- benzoyl)resorcinol. 11. A composition comprising a predominantly vinylidene chloride copolymer and from 0.1 to 10 per cent, based on the weight of the copolymer, of tribenzoyi resorcirol. 12. A composition substantially as described

* GB786145 (A)

Description: GB786145 (A) ? 1957-11-13

Preparation of optically active isomers of threo--ss-(p-nitrophenyl)-serine-methylester

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COMPLETE SPECIFICATION Preparation of Optically Active Isomers of Threo@-(pw Nitrophenyl)-Serine-Methylester We, CHINON GYOGYSZER ES VEGYESZBTI TERMEKEK GYARA R. T. a body corporate organise under the laws of Hungary, of To-utca 1-3, Ujpest, Budapest IV, Hungary, do hereby declare the invention, for which we pray that a patent may be granted to us, and : the method by which it is to be performed to be particularly described in and by the follow- ing statement :- The present invention is concerne with improvements in or relating to the preparation of the optically active forms of threo-~-(pnitrophenyl)-serine-methylester. Threo-/ ?- (-nitrophenyl)-serine derivatives are intermediates in the preparation of chlor- amphenicol, the latter being a substance of high therapeutic value. Since chloramphenicol is an optically active compound, it is advantageous to obtain its intermediates in the corresponding optically active form. Esters of racemic (p-nitrophenyl)-serines have already been resolved. According to Specification No. 715, 876 racemic erythro (p- nitrophenyl)-serine-ethylester and racemic threo- (p-nitrophenyl)-serine-ethylester may be resolved by means of dibenzoyl-(+)-tartaric acid. I. Elphimoff-Felkin,

H. Felkin and Z. Welvart have mentioned (Bull. de la Soc. Chim. France (1955) 145), without giving any detail, the resolution of racemic threo- (p-nitro- phenyl)-serine-ethylester by means of optically active lactic acid. It is to be noted, that racemic threo- (p > -nitrophenyl-serine-ethylester cannot be split into the optically active antipodes with d-rartaric acid. It has now been found according to the present invention, that the optically active isomers can be separated ifrom racemic threoS (p- nitrophenyl)-serine-methylester by fractional crystallisation of the d-tartaric acid salt of racemic threo-~-(p-nitrophenyl)-serine-methylester and by isolating from the diastereoiso- meric salts obtained the free methylesters of the optically active threo-ss-(p-nitrophenyl)- serines. The fractional crystallisation according to the invention is preferably carried out using alcohols as solvents. For example when using methanol as solvent, the d-tartaric salt of D (-)-threo-R- (p-nitrophenyl)-serine-methyl- ester crystallises out in an almost quantitative yield, while the d-tartaric salt of L( + )-threo ~-(p-nitrophenyl)-serine-methylester may be obtained from the mother liquor in a quantitative yield. The free optically active methyl ester may be obtained from the diastereioisomeric salts separated from the fractional crystallisation by any convenient method. In one such method the salts may be treated with aqueous ammonia or dilute aqueous alkalis, in order to liberate the basic esters. Alternatively the salts may be treated with alcoholic hydrochloric acid, whereby the hydrochlorides of the amino acid esters are obtained and by liberating then, if desired, the basic esters by treating the hydrochlorides with alkalis or an ion-exchanger. Other methods will be apparent to those skilled in the art. The methyl ester of racemic threo-, B-(p- nitrophenyl)-serine used in the present process can be prepared by an convenient methods of esterification with methanol from the serine. The preparation of the ester may be carried out for example in the following manner : 150 ml. abs, methanol are saturated with gaseous hydrogen chloride and 15 g. of threoss 6 (p- nitrophenyl)-serine are added. The mixture is then refluxed for 2 hours while hydrogen chloride gas is passed through. The solution obtained is then evaporated to dryness, the crystalline residue mixed with ether and filtered. The hydrochloride of threo-ss (p-nitro- phenyl)-serine-methylester is obtained which melts with decomposition

at 193-195 C. The yield is about 98 per cent. The said hydrochloride of the ester is dissolved in 80 ml. of water, the solution is filtered and while cooling with ice 100 ml. of 10 per cent sodium bicarbonate solution is added. Threo-- (p-nitrophenyl)-serine-methyl- ester is precipitated from the ice-cooled solu tion in a yield of about 80 per cent, which melts with decomposition at 137-138~ C. In order that the invention may be well understood, the following examples are given by way of illustration :- EXAMPLE I. 2. 40 g. of racemic threo-ss-(p-nitrophenyl)- serine-methyl-ester and 1. 50 g. of d-tartaric acid are dissolved in 50 ml. of methanol by heating. The solution is allowed to stand overnight at room temperature. White crystals are formed. The crystals are filtered off, washed with methanol and dried. The d-rartaric salt of D(-)-threo-~-(p-nitrophenyl)-serine-methyl serine-methylester is obtained in a yield of about 75 per cent. It melts at 169-170~ C. The rotary power is: (?)D: -5~ (H2O 2 per cent). The mother liquor is evaporated to dryness and the residue crystallised from 3 ml. of methanol, yielding a further 15 per cent. of the said salt On concentrating the mother liquor thus obtained the d-tartaric salt of L (+)-threo-ss- (p-nitrophenyl)-serine-methyl-ester is obtained. The pure product melts at 149-150 C. From the salt having the higher melting point the free aminoacid ester may be liberated for example as follows : 0. 6 g. of the said salt are added to a mixture of 3 ml. water and 4 ml of 10 per cent sodium bicarbonate solution. The precipitated aminoacid ester is then Eltered off, washed with water and dried. D (-)-threo-i- (p-nitrophenyl)-serine-methyl- ester is obtained, which melts with decomposi- tion at 150-151~ C. The rotatory power is : (a) : 27 (HCI N/1 2 per cent). Yield : about 90 per cent. The salt having the lower melting point and treated in the same manner gives L (+)-threo- (3- (p-nitrophenyl)-serine-methylester, the melting point of which is identical with that of the previous product EXAMPLE II. 28. 9 g. of d-tartaric acid are stirred in 200 ml. methanol until a clear solution is obtained. Then 46.1 g. of racemic threo-~-(p-nitrophenyl)-serine-methylester are added and stirring is continued for an hour at room temperature. The reaction mixture is finally refluxed for ten minutes while stirring. After allowing to cool to room temperature the crystals formed are filtered ofl, washed with some methanol and dried at 60 C. in vacuo.

36. 85 g. of the d-tartaric salt of Dt)-threo-ss-(p nitro- phenyl)-serine-methylester are obtained. Yield : 98. 5 per cent. The residue obtained on the evaporation of the mother liquor yields after recrystallization from water the d-tartaric salt of L (+)-threo-ss- (p-nitrophenyl)-serine-methylester. The optically active isomers of threo-/3- (p- nitrophenyl)-serine-methylester mentioned above have been referred to as D and L-isomers according to the configuration of the carbon atom next to the phenyl-residue. The configurations indicated have been ascertained by the reduction of the D (-)-threo- (p-nitro- phenyl)-serine-methylester with calcium borohydride to D (-)-threo-l- (p-nitrophenyl)-2- aminoLl, 3-dihydroxy-propane. What we claim is :- 1. A process for the separation of the optically active isomers from racemic threo-~-(pnitrophenyl)-serine-methylester which comprises separating the d-tartaric acid salts of racemic thrR- (p-nitrophenyl)-serine-methyl- ester by fractional crystallisation and isolating the free methylester of the optically active threo-ss-(p-nitrophenyl)-serine from either or both of the diastereoisomeric salts obtained.

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* GB786146 (A)

Description: GB786146 (A) ? 1957-11-13

Aqueous polymer dispersions and method of making the same

Description of GB786146 (A)

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FR1158157 (A) FR1158157 (A) less Translate this text into Tooltip

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PATENT SPECIFICATION Inventor: VERNON DEANE FLORIA 786, 146 Date of Application and filing Complete Specification: April 9, 1956. No 10757/56. Complete Specification Published: Nov 13, 1957. Index at acceptance:-Class 2 ( 6), P 7 C( 2: 8 B: 12 A: 14 A), P 7 D 2 A( 1: 2 A: 2 B), P 7 K 7, P 7 P 1 (B: C: El: E 3: E 5), P 7 PM(A 3; M X), P 7 (POG; T 2 D). International Classification;-COf. COMPLETE SPECIFICATION Aqueous Polymer Dispersions and method of making the same We, THE Dow CHEMICAL COMPANY, a corporation organized and existing under the Laws of the State of Delaware, United States of America, of Midland, County of Midland, State of Michigan, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention concerns certain new aqueous polymer dispersions and a method of making the same More particularly, the invention pertains to aqueous dispersions of interpolymers of major amounts by weight of non-ionizable vinyl aromatic compounds and minor amounts of ionizable vinyl aromatic sulphonates It pertains especially to such interpolymer dispersions which are substantially free of added emulsifiers or dispersants other than the interpolymers themselves, or the vinyl aromatic sulphonates employed in making the same The invention also pertains especially to a method of making such aqueous polymer dispersions in the absence of added emulsifying agents such as are conventionally employed in making other aqueous polymer dispersions. The aqueous interpolymer dispersions which 370 are provided by the invention are exceptionally stable against coagulation by freezing or

by addition thereto of inorganic salts such for example as sodium chloride, potassium chloride, sodium sulphate, potassium sulphate or calcium chloride They are more viscous than water and in some instances are solid, or non-flowable, at room temperature, but in such instances are capable of being thinned with water to obtain uniform aqueous polymer dispersions which are flowable and are of desired viscosities They are non-gelatinous and are colloidal polymer solutions such as are sometimes termed synthetic latices They are useful for a variety of purposes, e g as hydraulic fluids when brought to concentralPnice' tions having the desired viscosity values, and as media with which dyes or pigments may be admixed, e g to make waterpaints The aqueous dispersions of the interpolymers of from 55 to 65 parts by weight per cent of one or more non-ionizable vinyl aromatic compounds and from 35 to 45 per cent of an alkali metal salt of a vinyl aromatic sulphonic acid usually possess film-forming properties, i.e such a dispersion can usually be spread as a thin layer on a solid surface and be dried to obtain a continuous film of the solid interpolymer salt The aqueous dispersions of the interpolymers containing less than 35, e g from 1 to 30, per cent by weight of the chemically combined vinyl aromatic sulphonate often lack this film forming property and dry to form a layer of small particles, or agglomerates, of the solid interpolymers Any of the dispersions just mentioned can be rendered filmforming by incorporating therewith a plasticizer, i e an organic material compatible with the interpolymer Also, plasticizers are effective in decreasing the brittleness and increasing the flexibility of dried films of the interpolymers Accordingly in making water-base paints from the aqueous interpolymer dispersions not only a dye or pigment, but also a plasticizer, is usually added to the dispersion. Most aromatic liquids, e g benzene, toluene, xylene or diphenyloxide are effective as plasticizers for the interpolymers and can be incorporated into and dispersed throughout the aqueous interpolymer dispersion. The emulsifying agents such for example as ammonium oleate, sodium oleate, sulphonated sperm oil or higher alkyl aromatic sulphonates which are conventionally employed in emulsion polymerizations to form aqueous dispersions of polymeric materials, e.g of polystyrene, polymethylmethacrylate, or styrene-butadiene copolymers are retained in the polymer dispersions and modify the properties of the latter, sometimes in ways not desired Variations in the kind, quality or s O 2 786,146 proportion of an emulsifying agent, as well as variations in the other polymerization conditions, frequently affect the properties and utility of a polymer dispersion Also, the emulsifying agents frequently cause foaming of the emulsions Accordingly, careful control

is required in carrying out the conventional emulsion polymerization reactions in order to operate satisfactorily and obtain polymer dispersions of consistent and desired quality. Although aqueous dispersions of the interpolymers of the invention can be prepared by polymerizing an aqueous mixture of the corresponding monomeric compounds in the presence of an added emulsifying agent, the latter affects the properties of the resulting interpolymer dispersion in ways similar to those described above and its presence often is not desired The interpolymer dispersions of the invention are unusual in that they can be prepared from aqueous mixtures, i e not uniform emulsions, comprising substantially water-insoluble, non-ionizable, liquid vinyl aromatic compounds and water-soluble alkali metal salts of vinyl aromatic sulphonates in the absence of added emulsifying agents The invention pertains to the aqueous dispersions of such interpolymers prepared either in the presence or absence of an added emulsifier, but is concerned particularly with the aqueous interpolymer dispersions prepared in the absence of added emulsifying agents and free of added emulsifiers. Any non-ionizable liquid vinyl aromatic compound, or mixture of two or more of such compounds, can be used in preparing the aqueous interpolymer dispersions of the invention Examples of suitable non-ionizable vinyl aromatic compounds are styrene, ar-vinyltoluene, ar-vinylxylene, ar-chlorostyrene, ardichlorostyrene, and ar-ethylvinylbenzene The non-ionizable vinyl aromatic compounds are almost completely insoluble in water and in other aqueous media not containing an emulsifying agent. A water-soluble salt of a vinyl aromatic sulphonic acid, or a mixture of two or more water-soluble salts of vinyl aromatic sulphonic acids, can be employed in making the aqueous interpolymer dispersions Examples of suitable vinyl aromatic sulphonates are sodium styrene sulphonate, potassium styrene sulphonate, calcium styrene sulphonate, barium styrene sulphonate, sodium ar-vinyltoluene sulphonate, potassium ar-vinyltoluene sulphonate, sodium ar-chlorostyrene sulphonate, potassium ar-chlorostyrene sulphonate, sodium ar-vinylxylene sulphonate, and potassium arvinylxylene sulphonate The alkali metal monovinyl aromatic sulphonates, especially sodium monovinyl aromatic sulphonates, are preferred. The polymerization mixture comprises one or more of the non-ionizable vinyl aromatic compounds, a smaller amount by weight of one or more of the water-soluble salts of vinyl aromatic sulphonic acids, a polymerization catalyst, and at least sufficient water to dissolve the vinyl aromatic sulphonate The water may be present in as large a proportion as 70 desired The polymerizable starting materials are in relative proportions of from 55 to 99 parts by weight of one or more

of the nonionizable vinyl aromatic compounds and from 1 to 45 parts of one or more of the above 75 mentioned vinyl aromatic sulphonates In one preferred form of the present invention from to 97 parts by weight of vinyl aromatic compound is employed with from 3 to 40 parts by weight of vinyl aromatic sulphonate 80 Alternatively, 85 to 97 parts of vinyl aromatic compound and 3 to 15 parts of the sulphonate may be used Use of the vinyl aromatic sulphonate starting material in proportions larger than just stated often results in formation of 85 an aqueous solution, rather than a colloidal dispersion, of the interpolymer product. Although the polymerization mixture comprises the several starting materials just mentioned, a mnixture consisting only of said start 90 ikg materials cannot satisfactorily be employed to make the aqueous interpolymer dispersions of the invention A mixture consisting only of the above-stated starting materials comprises twyo phases, i e an aqueous solution of the 95 vinyl aromatic sulphonate and a separate phase of the insoluble, non-ionizablev vinyl aromatic compound The monomwric vinyl aromatic sulphonate has very little, if any, action as an emulsifier for the non-ionizable vinyl aromatic l OC compound When a mixture; consisting of said starting materials is stirred and heated, separate polymerization reactions apparently occur in the two phases of the mixture and, of the non-ionizable vinyl aromnatic compound 105 which reacts, a major portion forms an insoluble and undispersed mass or body of polymer. An emulsifying agent, e g sodium oleate or sulphonated sperm oil, can be added to a mix 11 ( ture of the above-mmntioned starting materials and the resulting mixture stirred and reacted to obtain a substantially uniform aqueous dispersion of the interpolvmer product However, the aqueous interpolymer -dispersions thus 115 obtained comprise the added emulsifying agent and are modified in properties by its presence. Furthermore, such employment of an added emulsifying agent involves the operating difficulties hereinbefore mentioned Although such 12 C a procedure for making the dispersions, and the dispersions thus prepared, are within the scope of the' inventioin, the aqueous interpolymer dispersions are preferably prepared in the absence of added emulsifying agents as 12. hereinafter described. It has been found that the presence of a small proportion of a soluble and highly ionized inorganic compound in the aforementioned aqueous mixtures of a non-ionized 13 C 786,146 786,146 vinyl aromatic compound and a water-soluble salt of vinyl aromatic sulphonic acid has an effect of promoting interpolymerization of the two kinds of vinyl aromatic compounds and formation of an aqu ous dispersion of the

interpolymer product and, as, a conlseaquence, of reducing in amount, or preventing, formation of an insoluble, undispersed pelymer product Thee aqueous, starting mixtures containing a minor amount of a water-soluble, ionizable inorganic compound comprise two' phases and are similar in appearance to, the mdxtures not containing such inorganic compound It is believed that the soluble, ionizable inorganic compounds cause a slight increase in solubility of the non-ionized vinyl aromatic compound in the aqueous phase of the reaction mixture; that they also serve as directional catalysts for occurrence of a copolymerization reaction between the two kinds of vinyl aromatic compounds; and that the copolymer is formed as dispersed colloidal particles that have an emulsiying action for water-insoluble organic material present, e g an emulsifying action, during and prior to completion of the polymnerization, for a considerable amount of the non-ionizable vinyl aromatic reactant and for at least part of any homo,-poylmer thereof which may be fored However, the invention is not limited by this, or any other theory, in explanation of the results which are obtained. Any of a wide variety of water-soluble, highly ionized inorganic compounds, e g having ionization, constants greater than 1 (h' at 25 C, can be used in small amount to promote, or catalyze, formation of the interpolymer in colloidal dispersed form Exceptions are inorganic compounds such as sodium nitrite or potassium nitrite, which are inhlibitors for the polymerization reaction, and inorganic compounds, e g soluble heavy metal salts, which react with one or both of the vinyl aromatic reactants, especially the vinyl aromatic sulphonate, or with the interpolymer product, to form a water-insoluble precipitate. Inorganic compounds reactive to' formr such a precipitate have not, as yet, been encountered, but they may exist Examples of suitable watersoluble ionizable inorganic compounds are sodium chloride, sodiumi bromide, sodium sulphate, potassium chloride, potassium bremide, potassium sulphate, calcium chloride, calcium bromide, barium chloride and barium bromide The inorganic salts of polyvalent metals, e g calcium chloride or calcium bromide, cause formation of an interpolymer dispersion which is more viscous than that obtained by use of an alkali metal salt such as sodium chloride, sodium bromide, or potassium bromide under otherwise similar polymerization conditions. The water-soluble ionizable inorganic compounds are usually employed in small proportion, e g in amount corresponding to between 0 03 and 1 per cent of the entire reaction mixture, the preferred proportion varying somewhat with change in the kind of inorganic conepound employed Proportions' of the ionizable inorganic compounds even smaller than just stated are sometimes effective Mixtures of two' 70

or more water-soluble, ionizable inorganic compounds which are not reactive with one another' to' form an insoluble precipitate, e g a mixture of sodium bromide and sodium sulphate or of potassium bromide and potassium 75 sulphate, can be used The alkali metal vinyl aromatic sulphonates which are employed as reactants in, the process of the invention are produced by a method which results in formation of an alkali, metal halide, e g a chloride or 80 bromide of sodium or potassium, and in some instances in formation of a corresponding alkali metal sulphate together therewith These inorganic salts, especially the alkali metal halides; and monre particularly sodium or potassium 85 bromide, are conveniently used for the purpose of the invention and are preferred The alkali metal chlorides or bromides are usually employed in amount corresponding to from 0.03 to 10, preferably from 0 05 to 0 5, per 90 centof 'the weight of the entire reaction mixture, but they can be used in larger proportions. An aqueous interpolymer dispersion can be formed by stirring, or otherwise agitating, the 95 mixture at a reaction temperature in the presence or absence of a piolymnerization catalyst, but the interpolymerization reaction occurs most readily, rapidly, and satisfactorily when a catalyst is employed The catalyst can; 100 be a water-soluble, inorganic peroxy compound such as hydrogen peroxide, sodium persulphate, potassium persulphate, or ammonium persulphate but preferably comprises a mixture of such water-soluble catalyst 105 and an oil-socluibile catalyst, i e a catalyst which is more soluble in a non-ionizable vinyl aromatic compound such as styrene than in water Examples, of suitable oil-soluble catalysts are organic peroxy compounds such 110 as lauroyl peroxide, lienzoyl peroxide, and tertiary-butyl peroxide The oil-soluble organic peroxides, when used alone, have not been satisfactory in that they caused formation of a large amount of insoluble, undispersed poly 115 meric material Mixtures, of from 1 part by weight of one or more water-soluble inorganic peroxides per 7 parts of one or more oilsoluble organic peroxides to 7 parts of the inorganic peroxide per 1 part of organic per 120 oxide have been satisfactory Regardless of whether the catalyst be a water-soluble in,organic peroxide or a mixture of the same and an organic peroxide, it is used in only small proportion, e g in amount corresponding to 125 between 0 1 and 1, preferably from' 0 12 to 0 5, per cent of the combined weight of the same and the water present in the reaction mixture. A mixture of the aforementioned starting materials in the proportions given above is 130 4 786,146 stirred or otherwise agitated, preferably in a closed vessel or in contact with an inert gas such as nitrogen, while at a reaction temperature The interpolymerization reaction can ba carried out at from rcom temperature or thereabout to the boiling

temperature of the reaction mixture It is usually accomplished by heating the mixture at temperatures in a range of from 40 to 1000 C The polymerization usually is continued until the reaction is substantially complete, but it can be terminated short of this point and the unconsumed portion of the palymnrrizable starting materials be vaporized from the resulting mixture Under is the preferred reaction conditions hereinbefore described, the product usually consists entirely of an aqueous colloidal solution, or dispersions of the interpolymer product However, the reacted mixtures sometimes contain a minor amount of insoluble, undispersed polymeric material that can be removed, e g by filtering or decanting, from the aqueous polymer dispersion that is formed as the major product. The abovedescribed method permits production of exceptionally concentrated aqueous dispersions of the interpolymer products, e g. dispersions containing up to 72 per cent by weight of the colloidal polymeric product In some instances, the concentrated polymer dispersions are non-flowable, paste-like, or solid materials at roami temperature However, they can be stirred together with water to obtain flowable aqueous polymer dispersions of lower concentrations Alternatively, polymer dispersions of as low a concentration as described can be formed directly by the method of the invention Thus, the invention permits direct production of the aqueous interpolymer dispersions in a highly concentrated form which is convenient for storage or shipment and which can, when desired, be diluted with water. The aqueous interpolymer dispersions of the invention are unusually stable against coagulation by acids, alkalies, or inorganic salts For instance, they can be treated with an acid or base to bring them to p H values of from 2 to 9, or they can be admixed with a considerable amount of an aqueous solution of an inorganic salt such as calcium chloride, without coagulation occurring. Following is a description by way of example of methods of carrying the invention into effect. EXAMPLE 1. This example illustrates the importance of having a small amount of a water-soluble, ionizable inorganic compound present in the aqueous polymerization mixture when not employing an added emulsifying agent In each of a series of experinments, a non-homogeneous starting mixture, comprising 60 parts by weight of wvater, 38 parts of styrene, 2 parts of sodium styrene sulphonate (H 2 C = CHCQH 15 O Na), 1.235 parts of benzoyl peroxide, and the parts by weight of sodium persulphate stated in the following table, was heated with agitation in a closed container at 80 G for 16 hours. Certain) of the starting mixtures were of the composition just stat d

Each of the other starting mixtures was of similar composition, except that it also contained the percentage by weight of sodiumn chloride or sodiuml bromide stated in the table After being heated, as described above, each mixture was examined to determine whether a substantially uniform aqueous polymer dispersion, i e colloidal solution, had been formed The sizes, i e. diameters, of the colloidal polymenr particles in certain of the dispersions were determined. The table gives the results which were obtained in each experiment The proportions of certain of the starting materials given in the table are expressed as the parts by weight of such material in a mixture which otherwise has the composition given above. 786,146 786,146 TABLE I Starting Mixture Comprises: Results Polymer Run Na 2 SO 8 Na CI Na Br Dispersion Polymer Particle No pts -pts pts Formed as Size in Dispersion the Product mu. 1 0 12 0 0 No 2 0 12 0 0 No 3 0 12 0 0 No 4 0 12 0 05 O Yes not determined 0 12 0 10 0 Yes,. 6 0 12 0 0 027 Yes 0 17 -0 21 7 0 12 0 0 050 Yes 0 17 8 0 12 0 0 125 Yes 0 17 9 0 12 0 0 250 Yes 0 17 0 12 0 0 375 Yes 0 17 11 0 12 0 0 500 Yes 0 17-0 18 12 0 06 0 0 130 Yes not determined The mixture employed in runs 1 to 3 reacted to form a mass of granules of an insoluble polymer, apparently polystyrene All of the other mixtures reacted to form stable colloidal solutions, of an interpolymner of styrene and sodium styrene sulphonate. EXAMPLE 2. A mixture of 84 parts by weight of water, 55 44 parts of styrene, O 580 parts of sodium styrene sulphonate containing a minor amount (probably about 0 3 weight per cent) of sodium bromide, and 0336 part of sodium persulphate was heated at 650 C and agitated in a closed vessel for 24 hours A uniform aqueous colloidal solution of an interpolymer of styrene and sodium styrene sulphonate was thereby obtained Although this experiment demonstrates that a colloidal soluti Qn of the interpolymner can be obtainedi by use of a watersoluble inorganic perody comnound as theo only catalyst, best results are usually obtained by use of a mixture of a water-soluble inorganic peroxide and an oil-soluble organic peroxide as the catalyst. EXAMPLE 3. In each of spirrals experiments, a mixture of water, styrene, sodiumr styrene sulphonate, sodium persulphate and benzoyl peroxide in the relative proportions given, as parts by weight, in Table 1 I was heated to 950 C and agitated in a closed vessel for 16 hours The sodiumi styrene sulphonate starting material was of the quality employed in, Example 2, i e.

it contained about 0 3 per cent by weight of sodium bromide Ini each experiment, an aqueous; colloidal solution, i e a dispersion, of an interpolymer of styrene and sodium' styrene sulphonate was obtained' In the following table, giving the compositions of the several starting mixtures, styrene is abbreviated as " S," sodium styrene sulphonate as " Na SS " and benzoyl peroxide is abbreviated as "BPO " 786,146 TABLE II Starting Mixture Run No H 20 S Na SS Na 253 08 BPO pts pts pts pts pts. 1 84 53 2 2 9 0 168 0 168 2 84 53 2 2 90 0 252 0 084 3 84 53 2 2 9 0 084 0 252 4 84 53 2 2 9 0 042 0 042 84 53 2 2 9 0 042 0 294 6 42 98 0 3 9 0 196 0 196 The aqueous interpolymer dispersions obtained in runs 1 to 5 were liquid and flowable at roomp temperature That obtained in run 6 was a non-flowable paste at room temperature, which paste can be thinned with water to render it flowable. EXAMPLE 4. A mixture of 84 parts by weight of water, 53 2 parts of styrene, 2 9 parts of sodium styrene sulphonate which contained about 0 3 per cent by weight of sodium bromide as an impurity, 0 336 parts of sodium persulphate, and O 56 parts of a sodium; capryl phosphate which is effective as an emulsifying agent, was heated with agitation at 950 C for 16 hours. A viscous aqueous interp-olymer dispersion was thereby obtained. EXAMPLE 5. In each of a number of experiments, a mixture of the several starting materials indicated in the following table, in the relative proportions given, was heated with agitation in a closed container to the temperature and for the time stated in the table Each of the metal vinyl aromatic sulphonates named in the table contained an appreciable amount, i e 0 3 weight per c-nt or more, of the corresponding metal breimide as an impurity The table gives the proportion of each starting material as parts by weight In the table, calcium styrene sulphonate is abbreviated as " Ca SS," arvinyltaluene is abbreviated as " VT," o-chlorolstyrene is abbreviated as " C-S," 2,5-dichlorostyrene is abbreviated as "CL 2-S," and lauroyl peroxide is abbreviated as " LPO " Other abbreviations are similar to those employed in preceding examples. TABLE III Starting Mixture Reaction Conditions T Non-Ionizable Vinyl H 20-Soluble Oil-Soluble Vinyl Aromatic Aromatic Inorganic Catalyst Run H 20 Reactant Sulphonate Catalyst Time Temp. No pts hrs,c C. Kind Pts Kind Pts Kind Pts Kind Pts. 1 15 VT 9 5 Na SS 0 518 Na 252 08 0 03 BPO 0 03 16 75 2 15 Cl-S 16 0

Na SS 0 518 Na 252 08 0 03 BPO 0 03 16 75 3 15 C 12-S 7 11 Na SS 2 89 Na 25208 0 03 BPO 0 03 17 80 4 15 S S 9 5 Na SS 0 518 Na 252 08 0 03 LPO 0 03 16 75 | 15 S 9 5 Na SS 0 518 H 20 O 03 BPO 0 03 16 75 + Fe(N 03)2 6 17 5 S 7 13 Ca SS O 872 Na 25208 0 035 BPO 0 035 16 75 7 200 S 200 Na SS 2 Na 2 S O 8 0 5 BPO 0 5 3 80 Approximately 0 00015 parts by weight of Fe(N 03)2 used per part of the H 202. All of the above mixtures reacted to, form aqueous colloidal solutions of the interpolymner products In each of the runs 3 and 5, a small amount of insoluble, undispersed polymer was also, found. EXAMPLE 6. Several aqueous colloidal solutions of interpolymers of styrene and sodium styrene sulphonate were tested for stability against coagulation by freezing and thawing and also by treatmnent with an aqueous calcium chloride solution Each of the colloidal solutions, i e. aqueous polymer dispersions,, was, prepared in the absence of added emulsifying agents by the method illustrated in the preceding examples. Each dispersion contained approximately 40 per cent by weight of the interpolymer The dispersions differed from one another asi regards the proportions of sodium styrene sulphonate chemically combined in the interpolymer One of the dispersions was initially formed as) a thick paste and was thereafter diluted with water to bring it to the concentration stated above The others were prepared directly as interpolymer dispersions of said concentration A portion of each interpolymer dispersion was frozen and thawed to determine whether the polymer is coagulated In the instances in which coagulation did not occur, the freezing and thawing operations were repeated Certain of the dispersions were frozen and thawed four times without becoming coagulated An aqueous 20 per cent by weight calcium chloride solution, was added gradually and in measured amount to a separate 15 ml portion of each of the aqueous interpolymer vl 00 s Qu\ dispersions while stirring the resulting mixture weight of chemically combined sodium styrene at room temperature, and the volume of the sulphonate in the interpolymer ingredient of calcium chloride solution required to cause each dispersion It also gives the results of the coagulation of the interpolymer was deter tests which were carried out. mined Table IV gives the percentage by TABLE IV Stability of Dispersion Freeze-Thaw Test Ca C 12 Test % Na SS Run in Inter No of Ml of No polymer Times Result 20 % Ca C 12 Result Frozen So Pn added 1 0 5 1 coagulated 0 2 coagulated 2 1 0 1,, 0 5,, 3 2 0 1,, 10 0 not coagulated 4 3 8 4 not 10 0 not coagulated coagulated 5 0 4 not 10 0 not coagulated coagulated -polymer dispersion was formed as a concentrated paste and was thinned to 40 % concentration with water.

As is evident from the table, the dispersions of interpolymers of styrene with 3 per cent or more of sodium, styrene sulphonate are more stable than the dispersions of the interpolymer containing smaller proportions of sodium styrene sulphonate. EXAMPLE 7. A mixture of 750 grams of water, 79 grams of sodium styrene sulphonate which was of 95 per cent purity and contained sodium bromide together therewith, 425 grams of styrene, 2 5 grams of sodium persulphate, and 2 5 grams of benzoyl peroxide was heated with stirring at to 85 C in a flask provided with a reflux condenser while bubbling nitrogen through the mixture to maintain an atmosphere of nitrogen in contact therewith The mixture was stirred and heated at atmospheric pressure under the above conditions for 3 hours The styrene and sodium styrene sulphonate were thereby interpolymerized and a fairly viscous colloidal solution of the interpolymer was obtained. Ex AMPLE 8. In each of two experiments a mixture of water, styrene, sodium styrene sulphonate (which was of 93 per cent purity and contained sodium bromide together therewith), sodium persulphate and benzoyl peroxide was agitated and heated in a closed vessel at 80 C for 5 hours, whereby an aqueous colloidal solution of an interpolymer of styrene and sodium styrene sulphonate was formed Each of the starting mixtures contained 18 parts by weight of water, 0 09 part of sodium persulphate, and 0.09 part of benzoyl peroxide One of the starting mixtures contained 6 6 parts by weight of styrene and 5 7 parts of sodium styrene sulphonate of the above-stated quality The other starting, mixture contained 7 2 parts of styreneand 5 2 parts of tho sodium styrene sulphonate described above Accordingly, in one of the experiments there was obtained an aqueous colloidal solution of an -interpolymer of approximately 55 weight per cent styrene and per cent sodium, styrene sulphonate, and in the other experiment there was obtained a colloidal solution of an interpolymer of approximately 60 per cent styrene and 40 per cent sodium styrene sulphonate A portion of each of the aqueous polymer dispersions thus prepared was spread as a thin layer onl a supporting surface and dried A fairly brittle, translucent film of the interpolymer was thereby formed Each of the films was completely redispersed, as colloidal particles in water, by shaking it together with water.

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* GB786147 (A)

Description: GB786147 (A) ? 1957-11-13

Method and means of detecting flaws

Description of GB786147 (A)

COMPLETE SPECIFICATION Method and means of Detecting Flaws We, MAGNAFLUX CORPORATION, of 7300 W. Lawrence, Chicano, Illinois, United States of America, a corporation organized and existing under the laws of the State of Delaware, United States of America, do hereby declare the invention, for which we pray that a patent may Ibe granted to us, and the method by which it is to be performed, to ibe particularly described in and; by the following statement:- This invention relates to a method and means for detecting flaws and more particularly to a method and means of flaw detection by which; a visual indication of flaws. in a test piece is obtained on a member independent of the test piece. According to this invention, a member having permanently uniformly distrlbuted magnesizable material therein, preferably a sheet of electrically insulating material having iron oxide particles dispersed therein, is placed on a surface portion of the article to rbe tested for flaws and! a magnetic flux is induced in the article. The magnetic flux will be generally uniform over the surface portion of the article excerpt as distorted by defects in the article and the flux pattern over the surface portion will be transferred to the sheet by permanent magnetization of the magrretizasble material therein. The sheet may then be removed from the article and free particles of magnetizable material are then placed. over the surface of the sheet. These particles will be generally uniformly distributedi over the sheet except portions of the sheet highly magnetized by the effect of flaws. in the article tested for defects.

The particles will be attracted to such portions and bunched together to provide a clear visual indication of flaws in the article tested. This invention has the advantage of providing a permanent record of flaws in the article In addition, the invention may be used to test under surfaces and other relatively inaccessible surfaces of articles for flaws. Moreover the invention is very efficient and provides a much clearer indication of flaws than methods andi apparatus previously used. Still further, the invention is highly efficient from the standpoint of power and equipment because only a short impulse of magnetization of the article to Ibe tested is necessary. Another advantage is that magnetizable particles in the sheet are fixed and only the strength and direction of magnetization affect them. They are not free to migrate into areas of high field strength and, hence, mask presence of cracks or other flaws. According to a particular feature of this invention, means are provided for inducing only a short impulse of flux in the article thus permitting use of a power supply with a very low power capacity. According to another feature of this invention, the ,thickness of the test sheet is so related to ithe depth of flaws below the surface of the article tested that optimum results are obtained. A further feature of this invention is in the provision of a method and means for testing the internal surfaces of pipes lor the like for flaws. Still another feature of this invention is in the provision of a plate of magnetizZile material over the test member to !greatly increase the magnetization of the material in the test member when the magnetic flux is induced in the article to be tested. This invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings which illustrate preferred embodiments and' in which: - Figure 1 is an isometric view of an article which may Ibe tested by the method and means of this invention; 'Figure 2 is a crossrectional view taken substantially along lines II--II of ig. 1 and illustrating flaws or defects in the article; Figure 3 is an isometric view illustrating the article of 3Rigs. 1 andi 2 held in magnetizing apparatus of this invention with a test member placed on a surface portion of the article; Figure 4 is a view illustrating a test mem- er having free particles of magnetizable material disposed on the surface thereof and illustrating how a clear visual indication of flaws is obtained; Figure 5 is a cross-sectional view taken substantially along lines V-V of Fig. 4 and illustrating a preferred ccmposition of the test member; Figure 6 is a view illustrating a tube-like test member placed inside the pipe or the like so that the internal surface portion of the pipe

can be readily tested; Figure 7 is a view illustrating a plate of magnetizable material placed over the test member to enhance the magnetization thereof; and Figure 8 is a view illustrating another preferred method and means for giving a visual indication of the flux distribution in the test member so as to indicate flaws or defects in the article tested. Preference numeral 10 designates an article which may be tested by the method and means of this invention. The article 10 to be tested may be of any electrically conductive material whether magnetic or non-magnetic but the method and means of this invention are peculiarly and particularly advantageous with test articles of magnetizable material such as iron or steel. The cross-sectional view of Fig. 2 illustrates flaws or defects 11 and 12 in the test article 10. The method and apparatus of this invention are used to give a clear permanent record and indication of such flaws or defects. In Fig. 3, the article 10 is held between a pair of supports 13 and 14 which may be adjustable supported on a frame 15. A member 16 of uniformly distributed maenetizable material is placed over a surface portion of the test article 10 and a magnetic flux is induced in the test article 10 to uniformly magnetize the material in the member 16 except as distorted by flaws or defects such as the flaws 11 and 12 in the article 10. It will be understood that anv method of or means for inducing the magnetic flux in the article 10 might be used such as a steady direct current conducted therethrough, a permanent magnet or a coil energized from a source of direct current A preferred and peculiarly advantageous method and means is illustrated in Fig. 3, in which the support 13 is connected through a switch 17 to one side of a capacitor 18 with the support 14 connected to the other terminal of the capacitor 18. The capacitor 18 mav be slowly charged up through a resistor 19 from a source of high D-C voltage connected to the terminals 20 and 21. After the capacitor 18 is charged up, the switch 17 may be closed to provide a short impulse of very high current which will flow between the contacts 13 and 14 through the article 10 and induce a high instantaneous flux in the article 10. This flux will uniformly magnetize the material in the test member 16 except as distorted due to the presence of flaws or defects in the test article 10. It will be apparent that this method and means for providing the flux is highly advantageous since the charging period for the capacitor 18 may he very long compared with the discharge period and the source of power connected to the terminals 20 and 21 need supply only a very small average current It will be understood that means other than the arrangement above

described may be used to induce a short impulse of high flux in the article 10 while conserving on size and power capacity of apparatus required. In combination with a unidirectional magnetizing flux, an alternating biasing flux may be used to achieve a magnetization of the member 16 more closely alike the internal structure of the article 10. Again, this may be accomplished in any desired manner, one method being illustrated in Figure 3 in which a source of alternating current 22 is connected in series between one side of the capacitor 18 and the support 14. Upon closing of the swkch 1.7, an alternating current from source 22 will be superposed on a unidirectional current from the capacitor 18. A pulsating direct current might also be used. It will be apparent that the arrangement of Figure 3, however, is highly advantageous in achieving optimum results with a minimum of equipment necessarv. After the member 16 is magnetized, it may he removed from the article 10 and free magnetizable particles such as powdered iron may-be disposed over the surface porticn thereof. The particles will uniformly distribute themselves over the test member 16 except that they will be attracted to highly magnetized portions of the member 16 which had been over flairs or defects in the article 10 in the magnetization step. The accumulation of particles over such portions of the member 16 will provide a very clear visual indication of flaws or defects as illustrated in Fig. 4. The test member 16 may be of any composition in 'which magnetizable material is generally uniformly distributed therein. Greatly improved results are, however, obtained by the composition of electrically insulating material with iron or iron oxide particles embedded therein. --Plastic and the like materials are suitable while elastomeric material such as rubber and the like are preferred since, with a flexible sheet form, the member 16 may be readily disposed against complex surfaces of articles tested. A particular feature of the invention is that the member 16 may be disposed against undersurfaces or other relatively inaccessible surfaces of articles to be tested for flaws. The advantages of this invention, in this respect, are readily apparent from Fig. 6 which illustrates a member 23 in the form of a tube dis posed inside a pipe 24 for testing the pipe for flaws and. defects. In this case, the member 23 is preferably iof an elastomeric material such as rubber with magnetizable particles such as iron or iron oxide particles dispersed therein. The tube 213 may then have a diameter, in its unsexed condition, less than the inside diameter of the pipe 24 to be tested, so that it ran be readily disposed' inside the pipe, and then it may. be inflated by

compressed air, for example, so as to snugly engage the inner surface of the pipe 24.. The tube 23 may then be deflated and removed from the pipe after which iron particles may be dispersed thereon to indicate flaws in the pipe. According to another feature of this invention', the thickness of the sheet member 16, or of the tube 23, is so related to the depth of flaws tested for in the article 10 or pipe 24 that optimum results are obtained. The disportion in flux distribution due to a defect in the test article 10 or pipe 24 causes. opposite magnetic polarization of the magnetizable particles or material; in the test members 16 or 23 spaced on opposite sides of the defect and, for a maximum of magnetization of particles in the test members 16 or 23, it is desirable that the magnetizable material or particles within the members 16 or 23. form a complete flux path inside the same. It has been found that the thickness of the test members 16 or 23 must be at least 0.1 the depth lof the defect below the surface of the article 10 or 24 in order to give optimum results with a clear visual indication of the defect. As an alternative to, or in addition to, makw ing the thickness lof the test member 16 proportionate to the ,dlepth of defect to be tested for in the article 10 as described above, the arrangement of Fig. 7 may ibe used in which a plate member 25 of magnetizable material such as iron is placed over the test member 16 to provide a good flux path and effective magnetization of particles in the test member 16 so as to insure a good indication of defects located at substantial depths below the surface of the article 10. Flux may be induced in the pipe 24 by the preferred apparatus and method of Figure 3 or in any desired manner. Another feature of this invention is illustrated in Fig. 8 in which a container or pan 26 has a generally flat bottom 217 covered with a liquid such as oil in which particles of magnetizable material, such as iron are suspended. The pan 26 is placed over the test member 1.6 and the particles suspended in the liquid 2 8 may move freely and accumulate over highly magnetized portions of the memher 1i6 to give a clear visual indication of defects. In this manner, the pan 26 may be used over and over again, eliminating the necessity of dispersing or dusting particles over the member 16 for each test. It wlli be apparent that this invention is highly advantageous in providing a very clear indication of flaws in articles, a permanent record of flaws in an article and an efficient test of relatively inaccessible surfaces of articles with relative ease and with a minimum in amount and! size of equipment. It will also be understood that modifications and variations may be effected without departing from. the invention.

What we claim is: - 1. A method of testing an article for defects, including the steps of placing adjacent a surface of the article a member having a mag- netizable material permanently uniformly distributes therein, and then inducing in the article a magnetic flux which is substantially uniform over the surface except as distorted due to defects in the article. 2. 'A method as claimed in claim 1 in which a unidirectional flux is induced in the article. 3. A method as claimed in claim 21 in which an alternating ibiasing flux is imposed on the unidirectional flux. 4. A method as claimed in claim 1, 2 or 3 in which the magnetic flux is induced in a short impulse. 'Si. A method as claimed in claims 1, 2, 3 or 4 in which freely movable magnetic particles are disposed on the member to show the flux pattern in the member and indicate defects in the article. 6 A method as claimed in claim 5 in which the particles are suspended in a liquid. 7. A method as claimed in claim 1, 2, 3, 4, 5 or 6 in which the article is hollow and in which the member is tubular, the member being inserted within the article. 8. A method. as claimed in claim 17 in which the member is expanded within the article so as to 'firmly engage the inner surface thereof. 9. A method, as claimed in any preceding claim in which the magnetic flux is induced in the article by the passage of electric current through the article. 10. A method as claimed in claim 9 in which the electric current is obtained by discharge of a capacitor through the article. 11. Apparatus comprising a member having a magnetizable material permanently uniformly distributed therein and' adapted to be placed against a surface of an article to be tested for defects, and means for inducing in the article a magnetic flux which is substantially uniform over the surface except as distorted due to defects n the article. 12. Apparatus as. claimed in claim 11 ineluding particles of magnetic material distributed over the member to show the flux pattern in the member and indicate defects in the article. 13. Apparatus as claimed in claim 12 ineluding a container for suspendiing the particles in a liquid and having a generally flat bottom arranged to be disposed on the member.

* GB786148 (A)

Description: GB786148 (A) ? 1957-11-13

Insoluble resinous copolymers of (chloromethyl) styrene and polyvinylaromatic hydrocarbons and nitrogen-containing derivatives of the copolymers

Description of GB786148 (A)

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PATENT SPECIFICATION 786,148 Date of Application and filing Complete Specification: April 23, 1956. No 12391156. Application made in United States of America on May 9, 1955. Complete Specification Published: Nov 13, 1957. Index at acceptance:-Clas's 2 ( 6), P 5 (A:D 2 X:Fl:K 7), P 5 P 1 E( 1:2:3:5), P 5 P 2 A( 1:2:5), P 5 P( 2 X: 3: 5), P 5 T(IC: 2 D: 2 X), P 7 A, P 7 D 2 A( 1: 2 A: 2 B: 4), P 7 (D 3: F 1), P 7 K( 5: 8: 10), P 7 PIE( 1: 2: 3: 5), P 7 P 2 A( 1: 2: 5), P 7 P( 2 X: 3: 5), P 7 T( 1 C: 2 D: 2 X), P 8 A, P 8 D 2 (A: B 2), P 8 (F 1: K 7), P 8 PE( 1: 2: 3: 5), P 8 P 2 A( 1: 2: 5), P 8 P( 2 X:3:5), P 8 T(XC:2 D:2 X), PIO(A:D 1 A:F 1: K 7), P 1 OPIE( 1:2: 3: 5), P 1 OP 2 A( 1: 2: 5), Pl OP( 2 X: 3: 5), P 1 OT(l C: 2 D: 2 X). International Classification:-CO 8 f. COMPLETE SPECIFICATION Insoluble Resinous Copolymers of (Chloromethyl) Styrene and Polyvinyl

Aromatic Hydrocarbons and NitrogenContaining Derivatives of the Copolymerg We, THE Dow CHEMICAL COMPANY, a Corporation organized and existing under the Laws of the State of Delaware, United States of America, of Midland, County of Midland, State of Michigan, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to improvements in ion exchange materials It pertains, more particularly to insoluble resinous copolymers of (chlorowmethyl)styrene and polyvinyl aromatic hydrocarbons, and nitrogen-containing derivatives of the copolymers which nitrogenous compositions are suitable for' the removal of anions from fluids The invention relates to a method of making the insoluble copolymers and their nitrogenous derivatives. United States Patent No 2,629,710 discloses the making of insoluble resinous compositions containing reactive chlorine atoms by chloromethylating insoluble cross-linked copolymers of styrene and divinylbenaene, or copolymers of styrene, ethylvinylbenzene and divinylbenzene, and teaches that the chloromethylated copolymers can be converted to ion exchange resin by reaction with amines. The patentee teaches it is desirable that as many chloromethyl groups as possible be introduced into the insoluble copolymer because the number of such groups' determines the number of polar groups that can be introduced into the final product, and the number of polar groups determines the capacity of the resin to absorb ions. However, the number of chloromethyl groups that can be introduced into the in. soluble cross-linked vinyl aromatic copolymers is dependent in part upon the degree of crosslinking, i e the proportion of divinvlbenzene in the copolymer A copolymer having a low degree of cross-linking, say containing one per cent by weight of chemically combined divinyl 45 benzene, can readily be chloromnethylated to form a product containing an average of about one substituent chloromnethyl group per aromatic nucleus, whereas a chloromethylated copolymer of a higher degree of cross-linking, 50 say a copolymer of styrene cross-linked with ten per cent by weight of divinylbenzene, contains a lesser number of substituent chloromethyl groups per aromatic nucleus in the copolymner It becomes more difficult to' intro 55 duce chloromethyl groups into, the vinyl aromatic copolymer as the proportion of divinylbenzene in the' copolymer is increased from to 20 per cent by weight or more. The aforementioned U S Patent No 60 2,629,710 also teaches that by varying the amount of divinylbenzene used in the preparation of the copolymer, variations can be made in the physical properties of the

polymeric material which carry through to the final ion 65 exchange material and which have a, marked effect upon its utility For most purposes, copolymers in which the divinylbeuzene component varies from 0 5 to 8 per cent on a molar basis, are employed Copolymers made with 70 from 0 5 to 2 per cent of divinylbenzene give finished ion exchange resins of low density and high porosity Denser resins of lower porosity are obtained by increasing the percentage of divinyibenzene in the copolymer to 75 from 4 to' 8 per cent. It is apparent that the use of the insoluble resinous copolymers of monovinyl aromatic hydrocarbons and polyvinyl aromatic hydrocarbons which copolymers are chloromethyl 80 ated and are employed for the manufacture of ion exchange resins having desirable characteristics, is restricted not only to the employment of cross-linked copolymers having a narrow range in the degree of cross-linking, e.g to from about 2 to 8 per cent divinylbenzene on a molar basis, but is also limited by the number of substituent chloromethyl radicals that can be introduced into the crosslinked copolymers There is need of insoluble resinous vinyl aromatic polymers containing reactive chlorine atoms having a wider range in the degree of cross-linking, and capable of being converted to insoluble ion exchange resins, e g quaternary ammonium anion exchange resins having high capacity for absorbing anions from fluids. Among the characteristics which render an ion exchange material, e g a quaternary amnmonium anion exchange resin, commercially attractive are: ( 1) a high capacity for absorbing anions from fluids per unit volume of a bed of the resin: ( 2) a uniform particle size; ( 3) a good porosity to permit rapid absorption of anions fromi fluids; ( 4) a high efficiency for regeneration of the resin; ( 5) a high operating-capacity; ( 6) a high resistance to breaking, cracking, or spalling of the resin. particles; ( 7) a low loss in ion exchange capacity over long periods of operation; and ( 8) a low volume change due to shrinkage or swelling of the resin particles during rep rated cycles of operation for the absorption of anions from a fluid and displacement of the absorbed ions from the resin by treatment with a regenerant solution' For most purposes a bed of an ion exchange resin should not undergo a change in volume exceeding 20 per cent, under operating conditions, and resins which exhibit a smaller change in velume under repeated cycles of operation for the absorption of ions from fluids and regeneration of the resin, are desired. It has now been found that insoluble resinous cross-linked vinyl aromatic copolymers which contain reactive chlorine atoms, and which copolymers are capable of being converted to insoluble anion exchange resins having among their prop erties the aforementioned

characteristics, can readily be obtained by polymerizing a mixture of a major proportion on a molar basis of (chlerom'ethyl)styrene and a minor proportion of a polyvinyl aromatic hydrocarbon, e g divinylbcnzene. St It has been found that copolymers of (chloromethyl)styrene and a polyvinyl aromatic hydrocarbon, e g divinylbenzene, containing the latter compound in a wide range of proportions, say from 2 to 20 per cent or more on a molar basis, can be employed for making anion exchange resins which exhibit to a greater or less extent the aforementioned characteristics. The anion exchange resins prepared from the insoluble resinous cross-linked copolymers of (chloromiethyl)styrene and a polyvinyl aromatic hydrocarbon, e g divinylbenzene, by reaction of the copolymer in the form of small beads, spheres, or sphereids, with a tertiary amine are surprisingly resistant to breaking, 70 cracking, or spalling, both during the preparation of the anion exchange resin, and in use of the latter for the absorption of anions from fluids The resin particles appear to be relatively free from internal strains and stresses 75 as compared to the product obtained by chloromethylating a copolymer of styrene and divinylbenzene. The copolymers of (chloromethyl)styrere and a polyvinyl aromatic hydrocarbon, e g 80 divinylbtnzene, being free, or substantially free, from internal strains and stresses are suitable for making anion exchange resin in the form of relatively large particles, e g. beads or spheroids of sizes between 10 and 85 mash per inch as determined by U S. Standard screens For some purposes anion exchange resins of such relatively large particle sizes in the form of beads or spheres are preferred, e g for removing complex metal 90 ions from aqueous solutions, or from aqueous clay suspensions Attempts to prepare strongly basic quaternary asnlmonium anion exchange resins in the fcrm of beads or spheres of sizes between'10 and about 20 mesh per inch by 95 the heretofore known method of: introducing chloromethyl groups as substituents on aromatic nuclei of an insoluble copolymer of styrene and divinylbenzene, then reacting the chlorornethylat-d coprilyiner with a tertiary 100 amine, results in the formation of a final product wherein a major proportion, if not all, of the larger resin particles are cracked or broken The miethod is not satisfactory for the preparation of such anion exchange resins in 105 the form of beads or spheroidal particles of sizes substantially larger than about 20 mesh per inch. The copolyeners of (chloromethyl)styrene and a polyvinyl aromatic hydrocarbon contain 110 the chlorcm ethyl groups on different aromatic nuclei in the copolymer molecule, and in most instances, contain a

substantially greater numher of chloromethyl groups per aromatic nucleus in the copolymer, than have the in 115 soluble chloromithylated vinyl aromatic polymers such as, chlorcmjethylated polystyrene, or chloromezthvlat'ed copolymers of styrene and divinylbeuzene croas-linked with a similar proportion of divinylbenzene The copolymers of 120 (chlorcmethyl)styrene and a polyvinyl aromatic hydrocarbon permit the introduction or substitution of a greater number of polar groups, e.g quaternary ammonium groups, in the copolymer molecule than has heretofore been 125 attained by chloromethylating vinyl aromatic copolymers containing more than about 8 per cent on a molar basis of divinylbenzen The final product, i e the anion exchange resins of the invention, have high capacity for the re 130 786,148 786,148 3 moval of anions from fluids. The invention provides new cross-linked vinyl aromatic polymers containing chloromethyl radicals on aromatic nuclei in the copolymer molecule which copolymers can readily be converted into anion exchange resins having high capacity for the removal of anions from fluids and having a greater degree of cross-linking and a wider range in the degree of cross-linking than have anion exchange resins heretofore prepared from chloromethylated vinyl aromatic polymers. The (chloromethyl)styrene to be employed in making the copolymers is preferably meta-, or piara-(chloromethyl)styrene However, any of the isomeric ortho-, meta-, or para-(chloromethyl)s'tyrene, or mixtures of the isomers can be used' The termi "(chloromethyl)styrene"' pertains to the isomeric compounds of the formula CH, = CH CGH 4 CHCI. The polyvinyl aromatic hydrocarbon to be employed as a cross-linking agent in preparing the copolymers can be divinylbenzene, divinyltoluene, divinylxylene, divinylethylbenzene, divinylethyltoluene, or trivinylbenzene Divinylbenzene is the preferred polyvinyl aromatic hydrocarbon It is usually obtained as a liquid fraction consisting principally of divinylbenzene in admixture with a minor proportion of ethylvinylbenzene The latter compound is of no benefit as a crosslinking agent, but its presence in minor amount is not disadvantageous The polymeric compositions, i e the copolymers of the invention, may also, contain in chemically combined form a small amount, e g 10 per cent by weight or less, of one or more other polymerizable vinylidene compounds such as styrene, vinyltoluene, vinvlxylene, ethylacrylate, methyl methacrylate, methyl iso p-r on enyl ketone, vinyl chloride, or alpha-methyilstyrene. The copolymers may contain from 0 5 to 50, preferably from 2 to 25, per cent on a molar basis, of the polyvinyl aromatic hydrocarbon chemically combined with fromi 99 5 to 50, preferably from 98 to 75, per cent of the (chloromethyl)styrene. The copolymers can be prepared in usual ways such as by polymerization

of a mixture of the monomers in mass or suspension in a liquid that is not a solvent for the monomeric material Suspension polymerization', in' which the monomers are first suspended in a liquid non-solvent for the monomers such as glycerine, water, or brine and are then heated, agitated and copolymerized, or in which the monomers' are scattered as droplets throughout a thickened aqueous medium such as a suspension of bentonite and water having a consistency sufficient to immobilize and prevent the droplets from coalescing, and are then heated without agitating and copolymerized, are preferred Such methods yield hard copolymers in the form of small spheres, globules, spheroids, or beads, and the size of the particles can be regulated and controlled. The polymerization is usually carried out at temperatures between 20 and 110 C, and lower or higher polymerization temperatures can be employed 70 The polymerization is accelerated by means of well known catalysts which provide oxygen. Examples of suitable catalysts are lauroyl peroxide, acetyl peroxide, benzoyl peroxide, stearyl peroxide, di-tert -butyl peroxide, di 75 tert -butyl diperphthalate, tert -butyl perbenzoate, or cumene hydroperoxide The catalysts are employed in amounts ranging from 0 1 to' 2 per cent by weight of the material to be copolymerized 80 The copolymers are converted to ion exchange resins by reacting particles of the insoluble copolymers with a nitrogen-containing base such as ammonia, or a primary-, secondary-, or tertiary amine The reaction 85 can be carried out by adding the ammonia or amine to the copolymer while the latter is suspended and agitated in a liquid which is a solvent for the ammonia or amine, e g water, benzene, toluene, chlorobenzene, or perchloro 90 ethylene The finely divided copolymer can be suspended in liquid ammonia, or the liquid amine, in which case no' other liquid need be used The mixture may be allowed to react at room temperature, or preferably elevated tern 95 peratures, e g at from 250 to 1200 C and at atmospheric or superatmospheric pressures. The copolymer is usually swelled prior to its reaction with the nitrogen-containing base by soaking the particles of the copolymer in a 100 suitable liquid such as' benzene, toluene, chloroform, carbon tetrachloride, methylene chloride or perchloroethylene at ordinary templeratures or above. The nitrogen-containing base to' be em 105 ployed in making the anion exchange resins can be ammonia, or a primary-, secondary-, or tertiary amine Examples of suitable amines are methylamine, ethylamine, butylamine, dimethylamine, diethylamine, dipropylamine, 110 ethylenediamine, diethylenetriamine, trimethylamine, triethylamine, tributylamine, dimethylethanolamine, methyldiethanolamine, dimethylisopropanolamine, methyldiisopropanolamine, benzyldimethylamine, diethylcyclohexylamine 115 or an alkylene

polyamine. It may be mentioned that ammonia, or primary-, or secondary ammes form weakly basic anion exchange resins containing amino groups, whereas tertiary amines, e g trimethyl 120 amine or dimethylethanolamine, form strongly basic quaternary ammonium anion exchange resins The latter resins are capable of absorbing anions 'such as chloride, sulphate, or hydroxyl ions from aqueous solutions, and 125 are preferred. Following is a description by way of example of methods of carrying the invention into effect, 786,148 EXAMPLE 1 (A) A mixture of 360 grams of (chloromethyl)styrene, 32 grams of divinylbenzene and 8 grams of ethylvinylbenzene, together with 2 4 grams of benzoyl peroxide as polymerization catalyst, was suspended in two litres of an aqueous solution containing 480 grams of sodium chloride and 2 grams of methyl cellulose ( 4000 cps) The mixture was stirred and heated at a temperature of 65 C. for one hour, then heated at 70 C with stirring for a period of 6 hours The Leopolymer was separated by filtering and was washed with water and dried The copolymer was in the form of hard beads of sizes between 20 and 50 mesh per inch as determined by U S. Standard screens The copolymer beads contained 19 9 per cent by weight of chlerinz by analysis. (B) A charge of 17 3 grams ( 25 cc) of the copolymer beads prepared in part (A) above was suspended in Frchlcro ethylene and heated at a remperature of 80 G for one hour to swell the beads The swollen beads were separated by filtering and were mixed with 334 grams of an aqueous 25 per cent by weight solution of trimethylamine The mixture was stirred and heated under reflux temperatures of up to 90 C for a period of 4 hours The resin was separated by filtering and was washed with water The wet resin, beads had a volume of 57 5 cc The beads were in the form of an insoluble resinous quaternary ammonium chloride composition The resin had an anion exchange capacity corresponding to 31 5 kilograins of calcium carbonate per cubic foot of a bed of the water-wet resin beads. EXAMPLE 2 A charge of 320 grams of para-(chloromethyl)styrene and 38 grams of a liquid fraction consisting of 80 per cent by weight of' divinylbe Gzene and about 20 per cent of ethylvinylbenzene, together with 2 grams of lauroyl peroxide as polymerization catalyst, was added to 125 cc of an aqueous solution of 99 91 per cent by weight of water, 0 03 p r cent of a water-soluble condensation product of diethanolamine and adipic acid, O 03 per cent of a water soluble reaction product of an ethylene exide-urea condensation product with formaldehyde, and O 03 per cent of bentonite. The mixture was vigorously stirred to disperse the monomer as droplets

in the aqueous medium Thereafter, there was added with gentle stirring 11 3 cc of an aqueous onz per cent by weight copper sulphate solution and 480 cc of an aqueous 4 per cent by weight dispersion of bentonite in water The resulting dispersion comprising the droplets of monomer scattered throughout the thiclened aqueous medium was sealed in a glass bottle and heated without agitating at a temperature of 500 C for a period of 14 hours, then at 80 C for 6 hours, to polymerize the monomers. Thereafter, the copolymer was separated and was washed with water and dried There was obtained 343 grams of copolymer in the form of beads of sizes between 30 and 50 mesh per inch as determined by U S Standard screens. The copolymer contained 19 9 per cent by weight of chlorine A charge of 325 grams of the copolymer was dispersed in liquid perchloroethylene and heated at a temperature of C for one hour to swell the beads The perchloroethylene was decanted and 1200 cc. of an aqueous 25 per cent by weight solution of trimethylamine added The mixture was stirred and heated gradually to a temperature of 900 C for a pericd of about 0 5 hour, then heated at 900 C for 3 5 hours longer The resin was separated, was washed with water, then with acetone and again washed with water The resin had an anion exchange capacity corresponding to 34 4 kilograms of calciumn carbonate per cubic foot of a bed of the wet resin. EXAMPLE 3 A copolymer of 87 7 per cent by weight of (chloromethyl)styrene, 9 8 per cent of divinyl 90 benzene and 2 5 per cent of ethylvinylbenzene was prepared by a procedure similar to that described in Example 2 The copolymer was in the form of rounded beads of sizes between and 60 mesh per inch A portion of the 95 copolymer was swelled in perchloro ethylene and the swollen copolymer reacted with trimethylamine employing procedure similar to that employed in Example 2 The resin had an( anion exchange capacity corresponding to 100 33.7 kilograins of calcium carbonate per cubic foot of a bed of the wet resin. Another portion of the copolymer beads was swelled in perchloroethylene and reacted with dimethyletharnlarm Inc by heating the swollen 105 beads with an aqueous 60 per cent by weight dimethylethanolamine solution at a temperature of 900 C for a period of 4 hours The resin was separated, was washed with water, then with acetone and again washed with 110 water The resin had an anion exchange capacity corresponding to 36 2 kilograins of calciumi carbonate per cubic foot of a bed of the wet resinr. EXAMPLE 4 115 A charge of 80 grams of (chloromethyl)styrene ( 98 2 per cent) and 3 4 grams of a liquid fraction consisting of 97 per cent by weight of

divinylbenzene and 3 per cent cf dthylvinylbenzene, together with 0 42 gram of 120 lauroyl peroxide as catalyst, was polymerized employing procedure similar to that described in Example 2 The copolymer was in the formf of rounded beads of sizes from 20 to 50 mesh per inch The copolvmenr was swelled in 125 percbloro ethylene, then mixed with 500 grams of ethylenediamine The mixture was stirred and heated at temperatures between 880 and 1070 C over a period of 4 hours The resin was separated and was washed with water It 130 786,148 with acetone and again washed with water. The product was an insoluble resinous quaternary amoniomum composition containing trimethyl ammonium chloride groups of the 45 formula -CH 2 NCI(CH,), as substituents on aromatic nuclei of the copolymer It was an anion exchange resin A weighed portion' of the product was dried by heating the same at a temperature of 500 C at an absolute 50 pressure of 10 millimetres; for a period of 3 hours It was then weighed to determine the percentage of water in the resin granules A swelling characteristic for the anion exchange resin was determined by immersing a measured 55 volume of the dried anion exchange resin granules in water for a period of one hour and thereafter measuring the volume of the water-swollen resin particles The swelling characteristic for the anion exchange resin was 60 calculated by dividing the volume in cubic centimetres of the water-swollen resin particles by the volume in cubic centimetres of the dry anion exchange resin initially used An anion exchange capacity for the resin was, also deter 65 mined The table identifies the copolymer by giving the proportions of chloromethylstyrene and divinylbenzene employed in preparing the same The table gives the percentage by weight of chlorine in the copolymer and a 70 swelling ratio for the copolymer in chloroform at 250 C The table gives the anion exchange capacity of the final product in otilliequivalents; per gram of the dry resin, a swelling ratio' for the chloride form of the anion 75 exchange resin in water at 25 C and the percentage by weight of water in the swollen resin granules The table also gives the anion exchange capacity in kilograins of calcium carbonate per cubic foot of a bed of the water 80 immersed anion exchange resin. was washed with a dilute aqueous solution of hydrochloric acid, was washed with an aqueous l-normal sodium hydroxide solution and rinsed with water until free from sodium hydroxide The resin had an anion exchange capacity corresponding to 61 7 kilograins of calcium carbonate per cubic foot of a bed of the wet resin. EXAMPLE 5 In each of a series of experiments, a mixture of chleromethyl styrene and a technical divinylbenzene similar to that described in Example 2, in proportions as stated in the following Table was suspended in an

aqueous medium and polymerized employing procedure similar to that described in Example 2 The copolymer was obtained in the form of insoluble hard resinous particles of sizes between and 50 mesh per inch as determined by U S Standard screens The percentage of chlorine in the copolymer was determined by analysis A swelling characteristic for the copolymer was determined by suspending a measured volume of the dry copolymer particles in' chloroform at 250 C for a period of 2 hours and measuring the volume of the swollen beads The swelling characteristic is, calculated by dividing the volume in cubic centimetres of the swollen beads by the volume in cubic centimetres of the dry beads. Other portions of the dry copolymer were suspended in perchloroethylene at a temperature of 80 C for one hour to swell the beads,. The perchloroethylene was drained from the swallen copolymer The swollen copolymer was suspended in an aqueous 25 per cent by weight solution of trimethylamine solution. The mixture was heated at a temperature of 800 C in a closed container for a period of 4 hours Thereafter, the resin was separated by filtering and was washed with water, then 786,148 TABLE Starting Materials Copolymer Product (Chloro Divinyl Swelling Capacity Swelling Water Capacity Run Methyl) Benzene Chlorine Ratio meq /gm Ratio in Kilogr. No Styrene Wt % in (dry) in Resin Ca CO 3/ Wt % % CHC 13 H 20 % cu ft (wet) 1 99 5 0 5 21 27 5 6 2 21 115 87 7 5 7 2 98 2 20 65 3 2 3 26 5 61 73 8 14 2 3 96 4 20 35 2 5 3 32 2 07 54 8 22 9 4 94 6 19 88 2 1 3 58 1 88 52 3 28 6 92 8 19 48 1 9 3 88 1 87 48 5 33 0 6 90 10 18 82 1 7 3 58 1 70 43 2 347 7 88 12 18 54 1 7 3 54 1 67 40 4 36 2 8 86 14 17 71 1 7 3 35 1 54 38 2 36 2 9 84 16 17 28 1 7 3 27 1 54 35 2 37 2 82 18 17 01 1 6 3 23 1 50 33 4 34 1 EXAMPLE 6 A charge of 20 grams of a, copolymer of 93 per cent chloromethyl styrenel and 7 per cent divinylbenzene on a molar basis, in the form of beads of sizes between 12 and 16 mesh per inch as determined by U S Standard screens was suspended in perchloroethylene at 80 C. and swelled The copolymer starting material contained 19 1 per cent by weight of chlorine. The excess perchloroethylene was drained from the beads A charge of 200 grams of an aqueous 25 per cent by weight solution of trimethylamine was added The mixture was stirred and heated under reflux at a temperature of 90 C for a period of one hour, then was heated with stirring at 90 'C for three hours longer Thereafter, the resin was separated by filtering, was washed with water, then with acetone and again washed with water The product was an anion exchange resin Ninetysix per cent of the water-swollen resin granules were in

the form of beads of sizes greater than 12 mesh per inch. For purpose of comparison, a charge of 19 grams of a copolymer of 88 per cent styrene, per cent ethylvinylbenzene and 7 per cent divinylbenzene on a molar basis, in the form of beads of sizes between 12 and 16 mesh per inch was placed in a glass reaction vessel equipped with a reflux condenser and stirrer, together with 38 grams of perchloroethylene. Thereafter, 57 grams of chloromethyl methyl ether was added The mixture was heated at a temperature of 550 C for one hour It was stirred and 9 6 grams of anhydrous zinc chloride was added The resulting mixture was f 0 a 9 \ ot stirred and heated at temperatures between 540 and 570 C for 4 hours Thereafter, the copolymer was separated and was washed and dried The chloromethylated copolymer contained 15 03 per cent by weight of chlorine. At this stage of the process the beads were net cracked or broken. A charge of 10 grams of the chloromethylated copolymer beads was suspended in perchloroethylene and swelled by heating the suspension at a temperature of 600 C for one hour The perchloro ethylene was drained from the beads and 200 grams of an aqueous 25 per cent by weight solution of trimethylamine added This mixture was stirred and heated under reflux at temperatures up to 900 C for a period of 4 hours The resin was separated and was washed with water It was; an anion exchange resin All of the resin particles were cracked or broken and were of sizes such that 96.3 per cent by volume of the water-swollen particles passed through a 16 mesh per inch U.S Standard screen.

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