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Johannesburg: Due to the support of suppliers, customers and Servochem members we are proud to announce that a massive donation of R130 500.00 was handed over to Johannesburg Children’s Home. What an effort by the industry! Special thanks go to:

Cape Town: Servochem Cape held their annual charity golf day on 7 November 2008 at Royal Cape golf club. This year’s nominated charity was the Heaven’s Shelter for abused women and children in Mitchells Plain. Many thanks go to our suppliers and customers for their generosity and support.

Charity Golf DaysJOHANNESBURG AND CAPE TOWN EVENTS

Mike Campbell NDE R11 890.00

Guy Reynolds Servochem CT R11 000.00

Tim Raaff Bryanston Country Club R10 000.00

Daniel Souchon Cray Valley R7 640.00

Lee Cochrane Harvey Roofing R7 000.00

Gordon Stay Impson Freight R6 060.00

Yvon Porhel Prominent Paints R6 000.00

Martin Rohm & Haas R5 500.00

Herman Putter Sigma Coatings R5 500.00

Jackie Crewe-Brown Ezee Brush R5 000.00

And many thanks go to all other donations

New Staff – WelcomeThe following staff members have been employed permanently as of 1st October 2008:Mackenzie Maje (Counting Clerk & Health & Security Rep)Vincent Ntobeng (Truck Assistant)Prince Ngubane (Driver) – Photo not available at time of going to press.

ServVol 31 • DECEMBER 2008

Thank you so much to

all our customers and suppliers for your support

through 2008. We wish you and your families a very merry Christmas and peaceful and

prosperous 2009.

From the Servochem Team

News• 2 Disperbyk 2155 • 3 Rohm Haas• 4 Grace Davison

• 6 Cray Valley Solvent-borne Binders • 7 Charity Golf • 8 Staff87

Common Questions:WHAT DOES THE TERM ‘PACKING DENSITY’ OR ‘PACKING RATIO’ MEAN?

SoccerServochem’s Soccer team are currently playing in the first league games, they have won 2 games since start of play and are still going to play in another 13 games for the first half of the tournament. We wish them all the luck in the upcoming games.

Big ‘0’ Birthday

Brian Campbell 12/11/08

60

PromotionWe have the pleasure of announcing a promotion for Sheron Coetzee to Purchasing Manager as of 1st September 2008. We wish Sheron all the best in this new position which we will develop over the next 12 months with many new and exciting projects. Noeleen Arthur and Angelique Ellis will be reporting to Sheron in our Purchasing Dept.Congratulations Sheron!

Team NewsMEET THE STAFF

Halloween CookathonEnthusiastic staff members took part in our Halloween Cookathon com-petition that took place on 31st of October 2008. The lucky winners were Diane Brymer for best display, Debbie Davies for best dish & Judy Jacobs for best dress.

CDP

Grap

hics

Over the last 10-15 years as water based and other types of heavily filled paint formulation have become more complex we hear more and

more that such and such formulation has a good or a bad pigment/extender packing density or ratio. What does the term mean and what are the positive or neg-ative effects of a good or a bad packing density?Very simply put the packing density expresses how compactly the pigment and extender particles fit to-gether in the dry film or basically how large the hollow spaces filled with binder are between them, i.e. the more spaces the worse the packing .

Following from this you can see that a dry paint film with only coarse particles will have big gaps and thus these gaps could act as weak links for things like wa-ter or stains to penetrate the film and attack the sub-strate or remain in the film. It would be much better if these gaps were filled with smaller particles of pig-ment or extender.

In theory it should be possible to calculate the pack-ing density if you know the PVC and the specific area of the pigments and extenders but in practice we nor-mally determine a good packing density by testing for the required film properties. Although in some respects this topic is quite difficult to understand, it is a very powerful tool that can give property and cost benefits if used properly.

For further information or advice contact the Author or your local Servochem

Philip GreenPaint Technology Consultant

10 Year Service AwardPam Bowater, Angelique Ellis, Miranda Nel and Morris Matjee pictured here with Andre Du Plessis and Barry Campbell celebrated their 10 year Anniversary at Servochem’s Annual Suppliers Spring Lunch at the Casal-inga Restaurant on 1st of Sept 2008.

Condolences

Our sincerest condolences go to Michael Fowler and

family for the loss of their mom who passed away on

3rd October 2008. “May your wonderful memories of your loved one bring you comfort

and strength during this time of sorrow”.

6

Solvent –borne woodstains based on Cray Valley Super Gelkyd technology have gained a strong reputation in this prestigious market. Their proven quality, performance and

application properties will ensure they comply with European Union 2010 VOC regulations.

Currently available Super Gelkyds can be formulated with a newly developed high solids alkyd to give 2010 compliant coatings with performance and rheology similar to that currently available.

super gelkyds

Ref No Structure %Fattyacid

Non volatile content

Typical viscosity mPa.s(25ºC @ 2500 s-1)

6006 WDA55 Medium-High 60 55 650

3915 WDA55 High 69 55 1250

High structured products such as Super Gelkyd 3915WDA55 and Super Gelkyd 6006WDA55 are used as the minor part of the total binder to impart structure. Both are supplied in high flash solvent.

Super Gelkyd 3915WDA55 is widely used with current alkyds at levels between 5 and 20% to impart thixotropy. The level used will determine the degree of thixotropy in the coating. This is a high structured thixotropic alkyd and will require dispersing at high shear to ensure homogeneous incorporation into the alkyd.

Super Gelkyd 6006WDA55 is medium-high structured material based on the flexible alkyd Synolac 6005WD70.

synolac – high solids alkyds

A new high solids alkyd SYNOLAC 4060 WDA90 has been developed especially for 2010 compliant woodstains. SYNOLAC 4060 WDA90 combines VOC compliance with performance. Drying, hardness and yellowing are comparable to existing alkyds used in this market. Typical properties of this new alkyd are shown below:

SYNOLAC 4060 WDA90 may be used as the sole binder or in combination with other high solids alkyds (eg Synolac 4113WDA80) to produce Newtonian woodstains. Some rheological additive like CRAYVALLAC PA4X20 will be necessary to prevent pigment settlement.

The SUPER GELKD thixotropic resins and the SYNOLAC alkyds are supplied in high flash solvent and as such they are exempt from the strict packaging and transportation regulations that apply to flammable products

Formulation in woodstains

Dependent upon the level of thixotropic resin in the total binder the structure of the woodstain can range from a creamy-like structure to full non-drip.

Many commercial woodstains with VOC >450g/l have a soft gel structure. 2010 compliant woodstains (VOC< 400g/l) with similar structure are obtained by using between 5 and 10% of thixotropic alkyd. Even the higher structured systems are still VOC compliant.

The rheological profiles of the compliant and non-compliant sys-tems are comparable. In practical terms this means they will have very similar application, leveling and anti-sag properties.

A starting point formulation for a soft gel type 2010 compliant woodstain based on SG3915WDA55 and Synolac SYNOLAC 4060 WDA90 is shown.

Further details on other high solids SYNOLACS and SUPER GEL-KYD technology are available from your Cray Valley representative or at http://www.crayvalley.com/

SYNOL A C 4060 W D A 90 Non Vo latil e 90% Viscos ity 2000 mPa. s @ 25ºC Ac id value <10 mgK OH/ g Vo latil e Hi gh flash low ar om ati c wh ite sp irit Fla sh po int >62ºC Fatt y acid con ten t 72%

S a m ple n a m e A B C D R a tio (o n s olid r es in)) S y n ola c 406 0 W D A 90 85 90 95 100 S G 39 15W D A 55 15 10 5 0

A s pec t Medium Gel Soft gel Slightly elastic Newtonian

P ro per ties V O C (g/L ) 397 386 374 334 IC I vis c o s ity (m P a .s ) 150

Weight Volume

Synolac 4060WDA90 575.20 581.01 SG 3915WDA55 103.41 113.64 Octa Soligen 69 5.69 5.22 Octa Soligen Ca 10 5.69 5.75 MEKO 5.69 6.18 Sicoflush Yellow 39.82 28.44 Sicoflush Red 5.12 3.66 Sicoflush Black 0.57 0.52 Propylene Glycol 11.38 10.94 D60 solvent 247.43 313.22

1000.00 1068.58

Viscosity = 150 mPa.s

2010 c ompliant woods tain (Oak tone)

VOC = 368g/l

Solvent- borne BindersFOR VOC COMPLIANT WOODSTAINS

Pictured (left to right): Jackie Crewe-Brown, Barry Campbell, Narisha Govender (JCH), Fiona Duke (JCH) and Andre Du Plessis

22635_Servonews Dec08.indd 1-4 12/11/08 12:19:42 PM

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1Rohm and Haas South Africa (Pty) Limited celebrates 10 years of business in South Africa this year.

The company, which was first founded in South Africa in 1964, dis-invested from the country in 1986 because of the Government’s apartheid policy. Rohm and Haas re-established its presence here in 1998 and re-purchased its previous New Germany-based plant.

“The company’s 10 year celebration is a very exciting landmark for the local team, which is committed to providing manufactur-ing excellence and sustainability in every aspect of business,” says Martin Rogers, plant manager of Rohm and Haas South Africa. “A cornerstone of the local plant is the supply of innovative technolo-gies to the paint and coating industry. Rohm and Haas is geared to meet the exact needs of its diverse customer base and keeps abreast with the latest international chemical, EHS and sustainable development trends.

“Innovations from Rohm and Haas in water based technology have transformed the coatings industry on an international level. With ongoing technical advancements, pure acrylic paint is today’s pre-ferred coating. It has superior durability, quick drying time, ease of clean-up and has an environmentally friendly make-up.

“The company’s commitment to the local market is to ensure paint manufacturers keep up with these international trends and take ad-vantage of the latest technical advancements.”

With just over 60 employees, Rohm and Haas South Africa pro-duces approximately 20 000 tons of water based emulsions for coatings, paints, paper, textiles and pressure sensitive adhesives annually.

2Rohm and Haas manufactures coatings raw materials, surface finishes, adhesives and sealants, ion exchange resins, as well as consumer and industrial speciality products for diverse in-

dustries throughout Southern Africa.

A positive development in the last decade is the local operation’s broad based black economic policy which encourages people, who were historically disadvantaged, to be self sustaining and success-ful, through transfer of skills and knowledge, so they can be entre-preneurs in their own right.

The company is a level-six contributor within the Department of Trade and Industry's broadbased black economic empowerment (BBBEE) code, which entitles customers to claim 50% BBBEE credits on a preferential procurement basis. Rohm and Haas aims to be a level-four contributor by 2012.

Empowerment initiatives include the establishment of small busi-nesses, with a commitment from Rohm and Haas to utilise the ser-vices of each new company. Rohm and Haas backed businesses include a cleaning service, technical laboratory, maintenance and engineering services, as well as a courier company and logistics function.

Rohm and Haas South Africa follows the international organisation’s strong tradition of consideration for the environment. The local op-eration’s mission also encompasses a pledge to establishing close relationships with the community and ongoing projects significantly improve the quality of life of those within the community.

Wetting and dispersing of pigments is widely recognized as one of the most important aspects of coatings

manufacture. Final film properties such as colour, transparency and hiding power are all affected by this process. But also some other interesting properties such as gloss, rheology and corrosion resistance can be influenced by the wetting and dispersing of pigments.

Traditionally, wetting and dispersing was a relatively simple process. The pigments used in the industry were mainly inorganic in na-ture. Furthermore they had a relatively large primary particle size and a low tendency to flocculate. As a result, low molecular weight additives could be used to achieve full pigment deflocculation. However, with the environmental pressure on certain chrome and lead based pigments, new organic pigments were introduced into the market. These pigments had much smaller primary particle size and a high tendency to floccu-late. The traditional additives were no longer suitable to stabilize these pigments and, in 1982, the first high molecular weight wetting and dispersing additives were introduced to meet the new demands of the industry. These new additives had multiple anchor-ing points for a stronger adsorption onto the pigment surface (figure 1). This resulted in vastly improved stabilization of the pigments once dispersed.

Figure 1: Showing comparison between high molecular weight and low molecular weight wetting and dispersing additives.

The main application for the new additives was for the highly technical automotive coating systems. However as the benefits of these products were realized, they found ap-plication in industrial tinting systems, marine and protective coatings, and interestingly the manufacture of LCD televisions. Today these products are seen as an industry standards and their success over the last 25 years should not be overlooked.

Still, with these products there were some limitations. High molecular weight polymers in any industry usually result in high vis-cosities. As a result, the polymeric additives usually needed to be diluted with solvents to achieve a workable viscosity. In most cases, solids levels were less than 50% and solvents had to be carefully selected to en-sure good stability in solution. Furthermore, production of the additives was achieved us-ing free radical polymerization. This relatively

“uncontrolled” process resulted in a wider distribution of molecular weights. Whilst the average molecular weight was accept-able, the presence of macro molecules, a by-product of the process, were thought to cause difficulties in resin compatibility.

In 1999, the first controlled polymerization techniques were commercialized. Full control of the polymerization process was possible and polymers could be controlled molecule by molecule. These new techniques allowed for the production of very specific polymeric structures such as gradient co-polymers and block co-polymers (Figure 2). Higher densities of pigment anchoring groups also ensured better pigment stabilization.

Figure 2: Comparison of different polymerization techniques.

These new methods of polymer manufacture allowed for many vitally important benefits. Whereas previously, starting raw materials for polymer manufacture were limited to expensive and very specific chemistries, the new techniques allowed for the use of rela-tively common raw materials. Additionally, the molecular weight could be controlled during polymerization, resulting in much narrower distributions. Furthermore, a wider range of solvent and resin compatibility could be achieved.

Figure 3: Molecular Weight Distributions using different

techniques

BYK has to date introduced a range of new polymeric additives based on Controlled po-lymerization. These products are part of the DISPERBYK 2000 series and have shown great commercial success in recent times.

The coatings industry itself has also been active over the last few years. There has been significant environmental pressure from government across the world to reduce the environmental impact of coatings. Much focus has been on the use of solvents and co-solvents, which are classified as VOC’s or HAPS. New technologies such as high solids, solvent free and UV coatings have become more common in today’s paint in-dustry. As a result, high solids raw materials

have become an absolute necessity.

To address the market demand, BYK has found a novel way to create a high molecular weight additive with 100% solids. In tradi-tional linear polymers this is not possible, but with the use of controlled polymeriza-tion techniques and some new chemistries, BYK was able to create a spherical polymer of high molecular weight. This resulted in a product with superior performance, zero solvent and workable viscosity (figure 4). The product has also been tailored for excep-tionally wide resin compatibility, in low and medium polarity systems.

Figure 4: Comparison of linear and spherical structures.

In the field, DISPERBYK 2155 has shown ex-cellent millbase viscosity reduction allowing for high pigment loading. Transparency is always a good measure of pigment stability and results have been very comparable with the industry standard.

In conclusion, the coatings formulator now has a tool for creating environmentally friendly coatings. A unique wetting and dispersing additive with the following proper-ties:

Good millbase viscosity reduction •Excellent deflocculation / stabilization of pigments Non yellowing in baking systems•No impact on drying time of 2-pack •systems100% solids •Storage stable also at low temperatures •(<0°C)Wide compatibility•

All Technical Data Sheets and MSDS can be found at www.byk.com under Additive GuideFor any further details please contact the local BYK representative.

Disperbyk 2155NOVEL HIGH MOLECULAR WEIGHT WETTING AND DISPERSING ADDITIVES FOR ENVIRONMENTALLY FRIENDLY COATINGSTristan van Vuuren BYK

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