WOLAN TECHNOLOGIES Low Viscosity Trimethoxy Silane Terminated Polyether in Construction applications. STP Polymer .

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The older technology sealants used for filling gaps and joints in building exteriors and other structures are being replaced with the new and greener hybrid sealants using Silane Terminated Polymers for improved performance.

The sealant in the joints needs to be flexible and compress and elongate as the wall panels or the building sections move with weather conditions and even traffic caused vibrations when used on bridges and car parking buildings.

The joints can be between expensive stone panels on the outside of new buildings , as well as inside buildings in foyers, bath rooms and kitchens. They can be coloured to match the stone or the sealant can be made crystal clear so it looks like there is no sealant.

The sealant needs to not change colour when exposed to sunlight and pollution , and the hybrid sealants have better UV resistance when compared to the older Polyurethane technology sealants.

The new hybrid sealants based on trimethoxy silane terminated polyether's are better for applications currently using common silicone sealants, where the oils used to make silicone sealants come out of the sealant and stain the stone or concrete and make the face look dirty and poor quality.

The sealants based on a low viscosity 25000 MW polyether have the benefits of both silicone and polyurethane technology, so a true hybrid technology that removes the disadvantages of the older products.

The trimethoxy silane capped polyether polymers are ideal for making crystal clear sealants when thickened with fumed silica.

The trimethoxy silane capped polyether polymers can be catalysed with a tin free catalyst package for markets where tin catalyst is a problem..

CONSTRUCTION SEALANTS

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STP polymers are based on the new generation polyether polyols ,that are the same as used for PU sealants and capped with reactive silanes that are the same as used by silicone sealants, and this is where the hybrid name comes from.

The polyether chain is about twice the strength of the polysiloxane chain used in silicone sealant and lets the sealant have better recovery from movement and is also more compatible when mixed with plasticizers that do not come out of the sealant.

The crosslinking of the sealant to form the one part curing sealant uses the same Trimethoxy silane chemistry as used by some silicone sealants. The adhesion is excellent and in most cases with stone or concrete there is no need for primers.

The other big advantage over polyurethane sealant is that there are no bubbles formed when the hybrid sealant cures.

Si polyether Polyol

OCH3

OCH3

OCH3

OCH3

OCH3

Si

OCH3

CH3O

CH3O

CH3O

Si

+ H2O

- HOCH3

OCH3

Si

OCH3 CH3O

O

The polymer is ideal for crystal clear sealants

Trimethoxy 25000MW polymer ADVANTAGES

Softest long chain polyether for lower shore A 25 sealants with high movement capacity to 20% ASTM standards. Enables bubble free curing at normal temperature & humidity levels

Formulations have excellent adhesion to porous stone and concrete panels

Excellent adhesion to aluminium with no primers and a wash with green dimethyl carbonate solvent

Sealant has excellent UV and chemical resistance and can be painted to match decoration changes

Sealant formulations can use the cheaper coated PCC fillers now available to make thick sealant

Sealants are solvent and isocyanate free and safer for tradesman and DIY consumers.

Sealants can be made in the factory with maximum mixer temperatures of 60 degree C and low energy use

The trifunctional polymer is catalysed with low levels of tin containing chemical like DBTDK or DBTDL.

No hazard warning labels on the sealant product when displayed in retail stores.

Sealants can be thickened with fumed silica or cheaper urea thickeners

Si

OCH3

OCH3

OCH3

Design of SILANE TERMINATED Polymers

Si

OCH3

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Starting Formulation

25000 MW trimethoxy silane capped polymer in Construction sealants

Test Results

MANUFACTURING GUIDELINES.

Construction sealants with sufficient plasticizer are easily manufactured in a low temperature process .In the first stage the calcium carbonate and pigments are mixed with plasticizer such as DIDP or 2000MW diol . These are dispersed under high shear and high vacuum to get to 60 degree Centigrade. .Some inexpensive dry methanol can be added to help remove moisture that is on the particle surface and comes off easily. At 50 degree C when moisture is about 500 ppm the more expensive vinyl silane is added to remove the harder to get moisture locked inside the calcium carbonates.Once the powders are dry with the DIDP or other plasticizers ,the resin can be added safely under a dry nitrogen blanket .Then the thickener and other additives can be added .The catalyst with vinyl silane is the final addition before the sealant is filled into cardboard cartridges or sausage packs that are lined with aluminium foil.The sealants made with trimethoxy terminated polymer are very reactive , need low levels of tin catalysts and it is not recommended they be filled into thin wall HDPE cartridges.

Material Parts by Weight

1. Prepolymer Trimethoxy 25000MW 100

2. Plasticiser DIDP or 2000MW Diol 70

3. Filler Omyacarb 2T 170

4. Pigment TIO2 20

5. Drying Agent A171 and dry methanol 5

6. Thixotropic Agent Aerosil R202 10

7.Stabilizer and UV inhibitor

Tinuivin 765 and Irganox 1076 2

8. Adhesion Promoter Secondary amino silane KBM603 2

9. Catalyst DBTDL or DBTDK 0.5

Total 379.5

Standard

Tack free time 60 minutes

Shore A penetration 34 ISO 868

Tensile strength at break 1.2 Mpa ISO 37

Elongation at break 320 percent ISO 37

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Sealant applications

The main requirements for exterior sealants are:

• Low modulus even at low temperatures• Excellent UV resistance• High colour stability and no colour change• Good adhesion to porous and non-porous substrates• High tear resistance• Paint ability when needed• Resistance to cleaning procedures

• Bubble free Curing• No surface tack that gathers

dust and dirt

• Hybrid sealants based on Trimethoxy silane terminated polymers meet the above requirements.

Construction joint or gap sealants have specific requirements:

•Good adhesion to damp or dry porous and non-porous substrates•Compatibility to various substrates including plastics, paints and coatings•High colour stability and UV resistance with no chalking•Good dust and pollution resistance•Paintability when concrete is painted or redecorated

Polymer for Adhesive requirements

Adhesives for hard floors such as sports arenas require:

•High mechanical strength and recovery ,low creep.•High vibration resistance•Good chemical resistance•Excellent adhesion properties•.Moisture resistance

•Hard sports surfaces such as these are placed on concrete slabs and the products required are :•.moisture resistant membrane based on 25000 MW Trimethoxy resin•.adhesive layer based on 16000 MW Trimethoxy resin•.expansion joints in the wood floor based on above construction sealant.

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Adhesives based on trimethoxy 16000 MW polymer

Starting formulation

Properties

Manufacturing Instructions

The basic manufacturing process is the same low temperature method as for the construction sealant above where the PCC and GCC blend is dried with the plasticizer before addition of other additives. As floor adhesives are thinner and there is a need to spread easily, the viscosity and slump can be adjusted by the amount of PCC added to a coarser particle GCC like Omyacarb 5. Other thickeners are not needed.

As floor adhesive are normally sold in 15 litre pails, It is normal to adjust the open time with vinyl silane and a little dry DMC solvent for the applicator and temperature conditions on application.

Where fast cure adhesive is needed, we recommended to add a catalyst pack as an additive addition that is mixed into the drum before application.

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Material Parts by Weight

1. Prepolymer Trimethoxy 16000 MW 100

2. Plasticiser Diisodecyl phthalate 80

3. Calcium carbonates PCC and Omyacarb 5 blend 200

4. Pigment Iron oxide brown 2

5. Drying Agent Silquest A-171 4

6. Stabilizers Tinuivin 765 and Irganox 1076 4

7. Adhesion Promoter Secondary amino silane KBM603 2

8. Catalyst DBTDL(also fungal agent) 2

Total 394

Standard

Tack free time (min) 50 adjust with A171

Shore A hardness 45 ISO 868

Tensile strength (MPa) 2.5 ISO 37

Elongation at break (%) 250 percent ISO 37

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Adhesives for buildings and Saunas

The adhesive needs to be elastic and allow some movement of the wood floor or wood clad wall to reduce the noise that is generated by walking in hotel foyers or department stores. and running of sports people in sports arenas.

The careful formulation for hardness and recovery of the adhesive softens the impact of walking and running on the hard floor surface and makes sport more comfortable and less strain on the knees and ankles of sports people.

.For Bonding of furniture and other wood joints such as stairs, much harder adhesives are needed with higher shore A hardness and less elongation .This can be achieved by adding 25 to 50 percent of shorter chain triol trimethoxy polymer, which is lower viscosity with a higher crosslinking density. The use of 100 percent PCC filler also makes the adhesives harder , yet still allows some movement capacity.

A significant innovation is the ability to use Trimethoxy silane terminated resins as a clear adhesive with DIDP and fumed silica like Aerosil R972 as the only thickening agent that also gives the polymer strength . This lets the bonding of expensive timbers where the adhesive fills the expansion joints or seams and is not detracting from the wood appearance.

Wood is a particular problem as a construction material as it absorbs moisture and wants to move and expand. so adhesives need to allow for this movement and softer sealant is used in expansion joints around thePerimeter.

For Sauna applications high humidity causes mould and fungus growth ,and it is advised that the sealants and adhesive use DBTDL catalyst as this also at the same time provides fungal protection at the adhesive face with the wood surface.

Advantages of adhesives based on Trifunctional 16000 MW polymer

Please Contact vladimyr@wolantech.com for discussions on licensing options for the low viscosity polymers suitable for Construction applications shown above.