Rubber conference showcases Challenges of the African continent covered at 10M' event %t;

FROM the price, production and consump­tion of natural rubber to biomimicry and the challenges of retreading and repairing tyres on the African continent - delegates at the 20th National Rubber Conference of the Southern African Division of the Institute of Materials, Minerals and Mining (tOM3) were treated to a diverse range of topics deliv­ered by speakers from around the globe.

The conference - held at Glenburn Lodge in Muldersdrift near Johannesburg from 14-17 April - was attended by about 80 delegates from South Africa and abroad.

Kicking off the conference was Thomas Hollz, CEO of Mullotec Holdings who discussed The South African Economy in the Context of the New World Order and as a Member of BRIC'. Holtz said there were both 'pros and cons' to South Aftica's recently gained membership of BRIC (the 'emerging economy' group led by Brazil , India and China).

USouth Africa must see its membership as being an integral part of African growth and nol just the growth of BRIC. Further­more there are a number of other African countries, particularly Nigeria, who think they should be members of BRIC," he added.

Dr Dave Duncan and Anton Hanekom gave a jOint presentation, 'To BEE or not to BEE? There is no question'. Since his recent retirement Dave has been involved with the 10M3 Education Initiative. Anton is the training director of the Plastics Federa­tion of South Africa.

20th staging of conference an imponant feat for 10M3 THE recent staging of its 20th national rubber conference is a significant achievement by the Institute of Materials. The IOM3_ and in its for­mer identity as the Plastics & Rubber Institute (PRI) - has been presenting the conferences at two-year intervals for over 40 years now, even though the cycle has been interrupted by delays some years.

The organisation of the event has been rotated between the main 10M3 branches (Northern and KZN) and been presented at various venues around the country, includ­ing the 'bush' and the 'berg'. Given that most of the organisation has been managed on a voluntary basis , congratulations are due to all the individuals concerned.

This success has also made the conference a venue of choice for numerous top interna­tional and local speakers. Presentations at this year's conference included: • 'The SA Economy in the context of the New

World Order and as a member of BRIC' by Thomas Holtz (Multotec);

• 'To BEE or not to BEE?' by Dave Duncan and Anton Hanekomj

• Natural Rubber: Prices, Production, Consumption and Speculation by George Sulkowski (Centrotrade Deutschland);

• 'Raw Material Producers , Contribution to Energy Savings' by Dr Martin Fehrle (Evonik, Germany);

• 'Rubber from a fuels perspective' by Dr Chris

they want to stay in business, also explain­ing the various elements of the generic BEE score card by which companies are rated. He recommended that small companies focus on preferential procurement (buy-ing from BEE approved suppliers); skills development (allocation of a set percentage of the company salary costs to training);

Woolard (University of Cape Town); • 'Globalization ofthe Tyre Industry' by Lars

Larson (Know Polymers); • 'Turbocure Technology' by Pascal Consolaro

(REP France); • 'Biomimicry: Innovation Inspired by Nature'

by Ms Tess Rayner (Biomimicry South Africa);

• 'a,w-AJkanedithiol-ene Crosslin king of High Vinyl Rubber' by Dr Percy Hlangothi (Nelson Mandela Metro University);

• 'Technology Process Additives Developed for use with Different Mixing Techniques for Improved Performance' by Mario Kuschnerus (Schill + Seilacher Struktol GmbH);

• 'How much Zinc Reduction is Sufficient?' by Dr Robert Bosch (Rubber Nano Products):

• 'Processing Promoters for Highly Filled Silica Compounds' by Joerg Guntrum (Rhein Chemie Rheinau GmbH);

• 'Tyre Management for Africa: Opportunities and Challenges of Retreading and Repairing Tyres on the African Continent' by Brendan van Niekerk (Chemvulc Marketing);

• 'Reducing the Burden of Gum Costs at the Calender through On-line Measurement and Control' by Tony White (Honeywell EMEA);

• 'Fine Mesh Straining and Extrusion Applica­tions with Gear Pump Systems for Rubber Compounds' by Winfried Trost (UTH GmbH):

• 'New Banbury N Series' by Alan Ashworth (HF Mixing Group).

employment equity (training employees so that they have the skills to become part of management); and socio-economic development (such as supporting local communities).

It follows that education is essential if

1. To BEE or not to BEE -IOMJ chairman Hans Strydom with Anton Hanekom of the Plastics Federation and Dr Dave Duncan, who gave a joint presentation about black..economic empowerment, and George Sulkowski of Centrotrade Deutschland. 2. The writer of this article, Dave Hunt, with Sanj lutchman of the SABS, Steven Wright and A~drew Bannatyne of Plastichem, and lee Myatt of Delta Rubber. PHOTOS: lOWRIESHAAP

L 34 JUNE / JULY 2011 ----------------------------------- -1-

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diverse topics ••• .. : . •• focused on the 10M3 Rubber Division's recent establishment of an Education and Training Fund; the fund will be financed by companies within the rubber industry.

The Plastics Federation is playing an important role in this project by providing facilities and equipment. Anton spoke about the PFSA Training Division, detailing the courses available for different qualifications.

George Sulkowski of Centrotrade Deutschland lalked about 'Natural Rub­ber: Prices, Production, Consumption and Speculation', This included an overview of the natural rubber market, including the impact of the financial crash of 2008/2009 on prices.

"The increasing production in Africa and the Far East is having a significant effect on supply. However, this increase has been offset by dramatic rises in consumption in China and India.

fuel consumption," said Fehrle. Keeping to the theme, Joerg Guntrum

of Rhein Chemie Rheinau GmbH, who is responsible for sales and marketing of products for the rubber industry in CIS, India, near Middle East and Africa, talked about 'Processing Promoters for Highly Filled Silica Compounds'.

In line with the global reduction in vehicle emissions of carbon dioxide, new regulations will be introduced in 2012. Tyres produced after July 2012 for the EU market will have to be labelled to indicate fuel efficiency, wet grip and noise. Tyres account for 20-30% of fuel consumption, depending on the rolling resistance of the tyre. Development work on the effect of fillers on RR has shown that silica fillers are superior to carbon black when used in tread compounds. The reduction in RR is

"NR prices are in many cases affected by speculators and forward purchasing. In order to maintain sup­ply tt will be necessary to increase invest­ment, introduce re­planting programmes and investigate

The increasing approximately 20%.

The use of silica fillers involves various technologies, includ­ing mixing (silica-filled compounds are multi-stage mixed); polymer selection (for example, solution SBR and neodymium catalysed butadiene rubber, NdBR), the

production in Africa and the Far East is having a significant effect on supply However, this

material substitution to reduce the reliance on NR: said George.

increase has been offset by dramatic rises in

consumption in China and India.

Dr Martin Fehr1e of Evonik, who is based in Cologne, Gennany, discussed 'Raw Material Producers, Contribution to Energy Savings'. With ever increasing oil prices, energy conservation was becoming more important throughout the world, said Martin.

~In transportation the rolling resistance of lyres has a large effect on fuel consump­tion. In a car, the rolling resistance can ao:ount for 20% of the fuel consumption and in a truck this can increase to 30%. In Europe and the USA there are regulations governing rolling resistance, " he explained.

Fehrle said it has been predicted that global regulations for rolling resistance, wet grip and noise may be introduced and that all lyres would have to be identified and obeled accordingly.

"The grades of carbon black and silica used for tyres will affect the rolling resis­tance. A three-component system of carbon black (such as Eeora,,",), a silica (such as Ullrasi(il) and a silane (VP Si 363®) has been found to reduce rolling resistance by up to 13%, resulting in a 6% reduction in

type of silica and silane coupling agent.

Silica-filled compounds have a higher heat build-up during mixing and during the development work it was found that processing promoters used in carbon black-filled compounds actually increased the RR in silica-filled compounds. This lead to the production of Aflux 37 and Aflux 72, which have considerably improved processing. Aflux 37 is a blend of surface active substances with fatty acids.

It improves the silica dispersion and re­duces compound viscosity without affecting hardness and modulus. Depending on the amount of filler, 2-6 phr can be used and it is added during the first mixing stage.

Dr Chris Woolard of the Sasol Ad· vanced Fuels Laboratory at the Univer­sity of Cape Town presented a paper on 'Rubber from a Fuels Perspective'. There are numerous rubber components in vehicle fuel systems and their quality has a vital impact on performance. Woolard concentrated on polymeric O-rings and the research that he is doing on the swell of O-rings in various types of fuel.

"Although ASTM 0471-06 details the ~

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JUNE / JULY 2011 35 -.J

requirements of rubber seals in specified test fuels, in practice these fuels can be very different to those used commercially. This is particularly the case in aviation fuels where variations in the amount of synthetic fuel and aromatic content will govern the swell and or shrinkage of the seal,Q ex­plained Woolard.

In order to create a test that most closely relates to service conditions, a new test rig has been designed at the Sasollabaratory.

Lars Larsen of Know Polymers Incorporated, a consultant on polymer and compounding matters for a global client base, talked about 'The Globalisation of the Tyre Industry'. Lars detailed the history of the rubber industry, concentrating on the tyre companies, and pointed out that many of the world's famous brands - such as Dunlop - are now manufactured by other concerns due to mergers and takeovers.

Lars also pointed out that the tyre indus­try in China is growing at a phenomenal rate: one city in China has 10 radial tyre manufacturing plants!

Pascal Consolaro of REP France discussed Turbocure Technology,' a tech­nology developed in the last decade and based on better temperature control and balancing the quantity of rubber that goes to each cavity.

Consolaro explained that this is done by inverting the rubber flow so that the hottest rubber is in the middle of the rubber section going into the mOUld. The 'temperature inverter' is positioned just before the injec­tor nozzle. In addition a 'fill balancer' may be used to ensure that the flow to each cavity is at the same rate and does not alter after a split in the runner system. A third component, a 'fill balancer max', can also be included in the system. In con­ventional moulding the centre of the part

being moulded is the coolest and takes the longest to cure. Using a 'fill balancer max,' the compound in the centre of the part is hottest and consequently the cure time can be reduced.

A combination of the three different components gives the following advantages:

• Cure time reducticrI Injectioo time reductioo

• Material flow improvement So:n:h risk reduced • Cavity balance Better physical properties

• Less mould flash • Reduced labour coots • Reduced rejEct

Reduced energy consumptioo

Increased machine utilisation

Percy Hlangothi, who is studying for his PhD in Polymer Chemistry at Nelson Mandela Metro University and also lectur­ing physical and polymer chemistry at the university, talked about 'a,w-Alkanedithiol­ene Crosslinking of High Vinyl Rubber (Isogrip ' ")'.

Isogrip ™ is the commercial name for a synthetiC polyisoprene consisting of 3,4 vinyl isoprene (60%) with the balance being 1,4 isoprene and 1,2 isoprene.

Used in rubber compounds, Isogrip gives increased wet grip, low gas perme­ability, high damping/low resilience at room temperature and has a high glass transition temperature of -15 to _20°C.

Hlangothi's paper detailed the crosslink­ing chemistry of Isogrip with linear C,UJ­

alkanedithiols of varying chain lengths. The degree of crosslinking was found to be independent of the length of the alkanedi­thiol chain. This was confirmed using ATR FTtR (attenuated total reflectance Fourier transform infra-red spectroscopy).

Mario Kuschnerus, technical sales en­gineer for Schill + Seilacher Struktol GmbH with responsibility for Western Europe, South Africa and India, presented a paper

1. Speakers Dr Martin Fehrle of Evonik (left) and Dr Chris Woolard of the Sasol Advanced Fuels Laboratory at UCT (right) flank session chairman Spike Taylor (Multotec Rubber). 2. Speakers Pascal Consolaro of REP France (left) and Lars Larson of Know Polymers of the USA with session chairman Rod Lockhead (Evonik oegussa Africa). 3. Session chairman John Lithgow of Karbochem (second from right) with speakers Jeerg Guntrum of Rhein Chemie of Germany, Brendan van Niekerk of Chemvulc Marketing and Robert Bosch of Rubber Nano Products. 4. Oeon Riekert (second from right), the session chairman, with speakers Winfried Trost of Uth GmbH of Germany, a manufacturer of extruders ; Alan Ashworth of HF Mixing Group of England, who spoke about the new 'N' series Banbury mixers; and Tony White of Honeywell Automation & Control Solutions of Johannesburg. 5. Ceen Burger and Georg Cronje of Rubber Nano Products and conference coordinator Wendy Knott-Craig. PHOTOS' LOWRIE SHARP

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36 JUNE I JULY 2011

on 'High Technology Process Additives for use with Different Mixing Techniques for Improved Perfonnance'.

Although process additives have been used in rubber compounds for many years, there is ongoing development of new prod­ucts which will give improved processing. Modem injection moulding machines are generally automated due to demand for high productivity and uniform product quality. One of the main requirements of a process addi­tive is to improve the flow of the compound into the mould. This is particularly important when multi-cavity moulds are used. The additive must also be easy to disperse into the compound, not reduce the cure rate, give easy mould release and not foul the mould. As most moulding compounds have low viscosity and hardness which can affect d~persion, Struktol WB 16 has been widely used as a process additive for improved flow and release properties.

~1I is very effective in synthetic polymers, is highly crystalline, melts at 102°C and trials have shown that it is better to add it towards the end of the mixing cycle. From the work on WB 16, Struktol has developed a new range of process additives, the HT prod­ucts," Kuschnerus explained.

HT 204 is the equivalent of WB 16 but disperses easily at mixing temperatures just above 60aC. Consequently it can also be used in mill mixed compounds and gives compounds improved safety against scorch.

JUNE / JULY 2011 37

Continued from page 37

Kuschnerus discussed the results of a lab test comparing WB 16 flakes, WB 16 micro beads and HT 204. In each case, the additive was added with the curatives at 2 mins 45 secs with the dump time be­ing 3.5 mins.

"Microscopic images showed the improved dispersion of HT 204 and the reduction in tensile strength was lower than with WB 16, in fact it was only slightly lower than the control compound which had no additive. The

wrong and operator training is inadequate. "This situation creates a huge opportu­

nity for South African companies within the tyre retail , repair and retreading industries. Increase in mining operations in African countries is resulting in economic growth with a need for improved transportation of commodities," he said.

Van Niekerk said there was signifi­cant need for repairing and retreading of earthmover tyres in the mining industry.

~Retreading factories improved flow by the late addition in the mixing cycle was illustrated using spider mouldings," he added.

This situation creates a huge opportunity

can be viable in many African countries, es­pecially on the main transportation routes. The establishment

Brendan van Niekerk, business development man­ager at Chemvulc Marketing, presented

for South African companies within the tyre retail, repair and retreading industries.

of retail tyre outlets probably offers the biggest potential as there is a shortage

on 'Tyre Management for Africa: Opportu­nities and Challenges of Retreading and Repairing Tyres on the African Continent'.

Van Niekerk said that moving goods in Africa is challenging due to a lack of infrastructure and "some of the worst roads on the planet". T yre services are set up with little capital , the equipment is often not the best available, repair materials may be

of property fittec and balancec lyres," he addec.

However, education and training would be a key factor as at present many 'repair­men' were self-trained.

Tony White of Honeywell spoke about 'Reducing the Burden of Gum Costs at the Calender through On-Une Measurement and Control'.

As polymer prices continue to rise, the

1. Garth Sammons, Sarah Row­ell, Bernice (in front) and Marius Viljoen (behind), and Cheryl and Andre Steyn, all of MR Zinc Oxide

2. Gerry Vorgers of S&N Rubber and Paul Masimola of Multotec at the banquet; Paul was very active at the conference, asking many quality questions . .. a situ­ation which was very welcome since conference delegates in SA have historically not asked many Questions, even when they don't know what's going on!

dimensional control of products in order to minimise material usage is becoming more important. In the calendering process, op­erators tend to work. at the top of the speci­fied thickness range so that the product will not be rejected because it is underilauge.

White explained that in the Honeywen system, the on-line measurement can be either be a fixed point gauge or by scan­ning the full sheet width. The measurement is fed back to the calender controls which then adjust the bowl gap, roll bending andl or cross-axis to give the required gauge. When first instaned the system will give an indication as to the accuracy of the calender and whether any maintenance is required so that the machine can work to the specified limits.

White said that even a saving of 30 gI m' on a total compound weight of 800 gJrr/ can deliver a return on investment within three months. In addition there are gains in machine productivity due to reduced set-up times, faster running speeds and reduced scrap.

Winfred Trost of Uth GmbH of Fulda, Germany, presented a paper on 'Fine Mesh Straining and Extrusion Applica­tions with Gear Pump Systems for Rubber Compounds'. Unlike conventional screw extruders, the Uth system consists of

4. Kerry Kirkman and Or Martin Fehrle of Evonik group. 5. Simon Doyle of Barbe (UK), Rentia Smith of Chemserve and Wolfgang Ruschig of Barbe 7 Deutschland. 6. Rubber connection : West African group hosted visitors from its principal Centrotrade, an international supplier of rubber materials. Here we ft see (standing) Stephen Bois of Centrotrade UK and George Sulkowski of Centrotrade Deutschland flanking Grant Rosettenstein of WAG with, seated in front, P Willie Esterhuizen and Rob McNab of WAG. H

L- 38 JUNE I JULY 2011

a gear extruder, known as the ROII-EX®, developed in the 1990s. In the Roll-Ex system, the extrusion pressure is generated by two interlocking rotors and, due to the short dwell time in the unit, the risk of scorch is reduced.

The Roll-Ex system is particularly suited to fine mesh straining of rubber com­pounds where the end product (such as membranes, require a very clean material free from grit, undispersed ingredients and other foreign substances. The low volume of the system results in less waste when a compound change is necessary. Energy requirements are up to 70% less than a screw extruder.

The gear extruder may be used to feed a screw extruder with strained compound, for mould fill ing and calender feeding. Six different gear extruders are available with outputs of 70 up to 6 000 kg/hr, with hot feed compound giving higher outputs then oold feed.

Institute of Materials: Southern Africa Region

Eastern cape

""""""" p.041360 2D84 C, 082 9403109 ~m..co.za.

The final paper of the conference was presented by Alan Ashworth of the HF Mixing Group about the 'New BanbUlY N-Series'. The HF Mixing Group was formed in 2010 with the merger of Harburg­Freudenberger, Farrel Corporation and Pomini Rubber & Plastics Sri.

The formation of the HF Mixing Group has resulted in a new series of Banbury® Mixers called the N Series. This incorpo­rates the best engineering technology from each company within the group. One of the new features is a hydraulic ram, instead of pneumatic, which results in uniform ram pressure and rams movement.

The Keel Bottom ™ Weight is a new floating weight designed for the N-Series. It improves productivity and batch quality and the batch size is increased by 4-5%. Seven machines are available with a capacity range of 50 to 700 litres. There are also three principle rotor designs, NSTTM, MDSCTM and the ZZ-2 for the N-Series,

l(waZulu·Nala! """!~ c. 071 682 9S85 andre'.com:eIiUS@' @Itochem.co.la

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3. Martin Fehrle of Evonik of Ger­many and Bright Rwodzi of Dunlop Belting Products of Benoni

with the choice depending on the com­pound being mixed. Other rotor designs are also available based on machine size and applications. The HF Mixing Group is able to evaluate a client's compound in its laboratory to determine the preferred rotor design.

The dust stop unit has also been im­proved in that it is a sealed system which prevents the ingress of contaminants and increases the life of the unit.

The Advise ™ System is a mixing control automation system for different applications from production planning to on-line quality checks and inventory control.

SINCERE THANKS TO ALL THE COMPANIES WHO SPONSORED THE IOM~ CONFERENCE

Barbe GmbH, Carst & Walker, Dunlop Belting Products, Durban Speciality Chemicals, Evonik Degussa Africa, Goodyear Veyance Technologies Africa, Hanover Engineering, H&R SA Sales, Karbochem, Multotec Rubber, National Rubber/Matmin, Rhein Chemie Rheinau GmbH, Rubber Products & Mouldings, Summit Publishing, VMI Holland BV and West African Group.

7. Crighton du Preez of Anchor Chemicals, Omesh Sutan of Dunlop Mixing & Technical Services and Thulani Lembede of H&R. 8. John Gers of Gers Services flanked by delegates from two of the companies his company represents: Winfried Trost of UTH of Germany, a manufacturer of tyre building equipment, and Pascal Consolaro of REP International of France, manufacturer of injection moulding machines. 9. Dressed to kill! - John Lithgow, Lowrie Sharp and Barry Hutchinson at the banquet. PHOTOS: LOWRIE SHARP

JUNE / JULY 201 1 39