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Questions & Answers

As promised on our BYK Live Event we have prepared the answers to your valuable questions.

Turning Challenges into Changes: Regulatory driven Solutions at BYK

How do you see the upcoming even stricter regulations on perfluoro-C6 products?

BYK is aware of the upcoming changes and we have already identified affected products. The development of alternatives is already ongoing.

What will the PFOA regulation mean for your fluor modified acrylates?

The regulation which will affect our fluor modified polyacrylates is the regulation concerning PFAS (per- and polyflouralkyl substances). Currently there is no final decision on EU level on the use of such substances. BYK is aware of the situation and affected products and possible substitutions are in work.

How many ppb had "old" PTFE products before regulation?

The PFOA content of the "old" type of PTFE had a wide variation range, depending on the source (3 digit to 4 digit ppb range). The PTFE which is now used in all PTFE containing wax additive has a PFOA content below 25 ppb. You can find additional information here: Regulatory Affairs - PFOA-free PTFE Wax Additives – BYK

What is now the issue of including D4;D5;D6 in Annex XIV of REACH for Polydimetylsiloxane additives?

Polysiloxanes with a D4 or D5 or D6 content of equal or higher than 0.1% have to be labeled as SVHC. BYK is offering "purified" versions of almost all standard polysiloxanes with a D4 + D5 + D6 content below 0.1%. You can find additional information here: Silicone Additives with Reduced Content of Cyclic Siloxanes – BYK

What is the cost difference on the new low cyclic grades vs "old"?

Please contact your responsible BYK sales person or write us via

Have all affected tin-containing products of your portfolio been changed to the new catalyst package?

DISPERBYK-162 TF, DISPERBYK-163 TF, DISPERBYK-167 TF, DISPERBYK-2155 TF, and DISPERBYK-2163 TF are the first 5 products that have been changed to the new catalyst package. Other affected products of the wetting & dispersing additive portfolio, such as DISPERBYK-161, DISPERBYK-170, DISPERBYK-2150, and DISPERBYK-2152 are under development, so that the majority of the affected products will be changed to the new catalyst package soon.

What is the shelf-life of the "BF" products compare to the original grades, in opened and unopened containers?

The shelf-life of DISPERBYK-190 BF, DISPERBYK-199 BF, and DISPERBYK-2015 BF is 24 months in unopened, original packaging. Once opened, it is recommended to consume the material in due time. Although the products do not contribute to microbial growth in the presence of bacteria, molds, and yeasts. You can also always find the current shelf-life of our products on the product detail page on

How is BF grades microbiologically protected? High pH or amines?

DISPERBYK-190 BF, DISPERBYK-199 BF, and DISPERBYK-2015 BF do not contain any amines or are supplied at high pH value as these products do not have the ability to contribute to microbial growth in the presence of bacteria, molds, and yeasts as externally tested by third party institutes.

What kind of catalyst has replaced those containing tin?

Alternative organometal compounds, that selectively catalize the different chemical reactions required to synthesize these high moleacur weight wetting & dispersing additives, have been identified and established for the new DISPERBYK-TF series.

How well do the silicone and no silicone based defoamers additives mix? And is there any benefits of combining the two?

It is not unusual to combine a silicone free and a silicone defoamer in one formulation. They have slightly different working mechanisms: 
Silicone based defoamers reduce the surface tension. They provide spontaneous defoaming properties and they are responsible that foam bubbles burst easily at the paint surface. Silicone free defoamers can have very good de-aerating properties. Due to their controlled incompatibility they have a strong orientation to the interface liquid-air and move foam bubbles to the surface very fast. That means: a combination of a silicone and a silicone free defoamer can have a synergistic effect in a coating system. If a defoamer is needed in a new system, we as BYK recommend to test every defoamer by itself in the first step and try combinations only in the second step.

Modern technology trends for Coatings

We try DISPERBYK-2014, it pass in polyol resin but fail in polyester resin, how we can solve the incompatibility between base coat system and DISPERBYK-2014?

In our test DISPERBYK-2014 is compatible with most common acrylic and polyester resins. The incompatibility in the base coat systems are manly impact by the CAB. Depending on the used pigments, a reflocculation can occur due to the presence of high molecular CAB.

Is the effective on the color retention in Exterior paint, DISPERBYK-2014?

All tests we know have shown a good color stability for exterior application. No changes in color retention were observed. As color retention depends on various factors it is always needed to run tests in the specific paint system.

Is there any Amide based rheology modifier for moisture cure polyurethane sealant?

Yes, we recently launched RHEOBYK-7502 and RHEOBYK-7503 (only available in North America and Europe), both products are especially developed for sealant applications.

This effect of RHEOBYK-440 on corrosion protection is coming from a reaction with the epoxy binder, meaning besides providing the tixotropy it also works as a cross linker? Should be consider it in the stoichiometry of the reaction?

No, RHEOBYK-440 does not crosslink with the Epoxy binder. So there is no need for consideration in the stoichiometry calculation. RHEOBYK-440 does not improve corrosion protection, but has no negative influence on it.

Also regarding RHEOBYK-440. Is it only recommended for epoxy systems? I am in love with RHEOBYK-425, it works very well in our 2K waterborne polyurethane system. Now I am thinking how it would work in my system.

RHEOBYK-440 was developed for 2-pack epoxy systems, but the use of this product is not limited to one system. So we recommend RHEOBYK-440 also to be tested in other systems.

Is it fair to compare BYK-3450 & BYK-3451 with BYK-3480 & BYK-3481 or is the latter pair perhaps more versatile?

Chemically wise the BYK-3450 and BYK-3451 are different to the BYK-3480 and BYK-3481. BYK-3480 and BYK-3481 are higher in molecular weight and less polar compared to the BYK-3450 and BYK-3451. All four products will reduce the surface tension in aqueous formulations and thereof improve the substrate wetting. The key point of BYK-3450 and BYK-3451 is the lower molecular weight and very fast and excellent spreading properties, especially on low polar substrates, whereas the BYK-3480 and BYK-3481 are designed for spray applied systems (but not only for that). BYK-3480 and BYK-3481 can be used without causing additional foam stabilization and often they enhance defoaming. Beside that they also provide leveling and they create very nice surface properties in aqueous systems.

Do the (macromer) products influence the surface tension of the liquid paint?

Even the products are able to increase the surface energy, they will not increase the surface tension of the paint. Products like BYK-3550, the latest development and partly also BYK-3566 are able to lower the surface tension of the liquid paint in solvent-borne systems. In water-based systems you still need a silicone surfactant to lower the surface tension to insure sufficient substrate wetting.

Does BYK-3565 / BYK-3566 would helpful in solvent based primer followed by S B basecoat & SB Clear coat?

The increase of surface energy helps especially, when the next layer is water-based. But the increase of the surface energy can help also in solvent-borne systems to improve the wetting of critical layers when these are applied with lower film thickness. The increase of surface energy sometimes has also an positive impact on the interlayer adhesion. Here it makes also sense to include the BYK-3560 in the test series.

BYK's Contribution to environmentally friendly Coatings

Why do you use ASTM D6866 and not DIN16640?

Up to now mainly ASTM D6866 was requested by our customers. If certification according to DIN EN 16640 is needed, please send us a request via .

What are the diameters of the agglomerates (of CERAFLOUR 1000, CERAFLOUR 1001 and CERAFLOUR 1002)?

CERAFLOUR 1001 as finest version has a D 50 value of 3 μm and a D 90 value of 7 μm. CERAFLOUR 1000 as medium sized product has a D50 value of 5 μm and 11 μm. CERAFLOUR 1002 has the biggest particles with D 50 value of 6 μm and a D 90 value of 31 μm. For details please take a look at the Technical Data Sheets which can be found on product detail pages on .

When do you know if CERAFLOUR 1001 and CERAFLOUR 1002 will be DSL listed?

For details about regulatory affairs or updates about listings please contact us:

With respect to renewable raw materials in general: How about costs? From your perception, is the market already willing to pay more for this? Especially considering the comparably low impact on the final system in case of additives that typically are used in low concentration?

Requests from our customers for biobased additives are increasing. We start with renewable raw materials, which are already available with comparable prices. More renewable raw materials will follow in future when volumes increase. Transformation of our products to complete renewable raw materials will be stepwise.

Bio based carbon means more deforestation? Rainforest is replaced with corn fields or palm treen plantations????

We work closely together with our raw material suppliers and also include other sustainability aspects in our decision for a new raw material. We also consider raw materials from waste streams or directly from CO2.

How do you make sure that the vegetable oils have exactly the same composition from one batch to another considering inherent and unavoidable variability of natural materials?

We work closely together with our raw material suppliers to guarantee a constant quality. In most cases biobased raw materials show a consistent quality.