Protective and Marine Coatings
Please can you recommend a suitable rheology additive for a xylene based alkyd paint?
You have different possibilities. If you want to use a liquid rheology additive, you can use BYK-7411 ES (Poly urea) or BYK-430 and BYK-431 (Polyamide). Both products can be post added. If you want to use a clay based additive, TIXOGEL-MP is one choice, also suitable is one of our mixed mineral thixotropes, GARAMITE-1958. The MMT technology provides high sag resistance and low viscosities due to strong shear thinning effect.
Can you recommend a dispersant for Zinc dust in solvent borne system which will keep zinc from agglomerating but not insulate the particles from making good electrical contact.
Try BYK-9076 with 0.5% in total formulation. It has been confirmed by cross-section that by using this recommended additive, you can get much more homogeneous zinc dust distribution in your paint film, and, salt spray test demonstrate that with those additives your paint can get better anti-corrosion performance.
Which dispersant agent is your recommendation for fluorocarbon resins? I am interest in all kind of pigments.
For most types of OH-functional fluorocarbon resins, dissolved in aromatic solvents/ esters, we suggest our DISPERBYK-2025 or DISPERBYK-140 to disperse both inorganic and organic pigments in this binder. The additive dosage is as follows: Titanium dioxide: 2% additive solid on pigment, Inorganic pigment: 10% additive solid on pigment, Organic pigment: 30% additive solid on pigment, Carbon black: 50% additive solid on pigment. DISPERBYK-2025 and DISPERBYK-140 are very good for almost all kinds of organic pigments and carbon black dispersing, in case you want to disperse DPP type organic red pigment, please use DISPERBYK-166 as dispersion agent. It will get good results.
I am studying a system with high content of SiO2 powder as filler in epoxy system, so sedimentation is a big problem. Can you give me advice how to handle the problem?
To avoid sedimentation the first step is to use the right type and the right amount of wetting and dispersing additive. Try with 6-10% of DISPERBYK-103 calculated on SiO2. Next step is to select a proper rheology additive to counter the settling of SiO2. If you want to use a liquid rheology additive, you can use BYK-430(Polyamide).This product can be post added. If you want to use a clay based additive, TIXOGEL-MP 250 is one choice, also suitable is one of our mixed mineral thixotropes, GARAMITE-1958. The MMT technology provides high sag resistance and low viscosities due to strong shear thinning effect.
I am working on a TiO2 pigmented solvent free epoxy. I have found severe loss of hiding during curing. I find TiO2 disperes fairly well in the epoxy, and even better in the amine curing agent without dispersant, but it leads to loss of hiding cure. What can I do?
The problem mainly occurs due to flocculation of titanium dioxide. To avoid this kind of phenomena, right additive and right additive dosage are both important. Even when it looks fairly well in the mill base. Try DISPERBYK-2152 or DISPERBYK-111 in the epoxy part during the grinding of the pigment. The dosage is 2% of solid additive of titanium dioxide.
We are developing 2 pack polyurethane coatings. Sometimes, the cured coating shows flooding and floating. The problem is worse, when the coating colours are dark: blue, grey, green. Can you give us any suggestion?
Organic pigments like phthalocyanine blue, phthalocyanine green and carbon black are the most difficult pigments to be wetted, dispersed and stabilized. One vital factor is the stabilization by using a right wetting and dispersing additive. If you produce co-grinds, one additive should be able to stabilize all of the pigment and fillers. DISPERBYK-2013, DISPERBYK-2055 and DISPERBYK-2155 are such additives. The next part is the dosage: As a general guide for TiO2 2% sop (solid additive calculated on pigment), for organic blues and greens 30-40% sop and for carbon black 40-100% sop. Often a pigment synergist is needed for phtalo blue and green. For blue you can use 3-5% sop BYK-SYNERGIST 2100 and for green 3-5% BYK-SYNERGIST 2100or 2102. The synergist should be added in the grind, before adding the W&D additives.
I am working on an epoxy system, which is highly filled and I run into the following issue: It it very high viscous, but however the pigments and fillers settle. What can I do?
To improve the flow, you should use a viscosity reducing wetting and dispersing additive, like DISPERBYK-110, DISPERBYK-142 or BYK-9076. Dosage depends on amount and type of used solids. As a generel guide, 2% sop (solid additive calculated on pigment) is good for TiO2, 5% sop for inorganic pigments and 0.5% sop on fillers. Regarding settling, you have two options, one is GARAMITE-1958 and the other one is BYK-430. 1% delivery form calculated on component A should be enough. These rheology additives provide excellent shear thinning effect.
I need to disperse fumed-silica into liquid epoxy resin to thicken the binder and a rheology agent to stabilize the viscosity, improving flow features when processing. Which BYK additives can I use to meet the requirements?
We are developing 2 pack waterborne epoxy anti-corrosion coatings. Now in my lab experience, pinhole is always observed in the coating film. Do you have any ideas? What kind of surface additives do I have to use?
For waterbased epoxy pigmented coatings, BYK-DYNWET 800 N and BYK-349 should be tested for substrate wetting. Main reason for pinholes are air bubbles. So you have to add a suitable defoamer. We can recommend BYK-024 as a starting point. If BYK-024 is not strong enough, try BYK-017. To avoid pin-hole, you also can use BYKETOL-WS. It is a levelling additive with defoaming property which can also be used to keep film surface open longer after application. This is helpful to avoid pin-hole problem.
We are looking for an additive which prevents our heavy duty epoxy coating from sagging when applied horizontally.
Due to our new rheology additive product portfolio, you have multiplie oppurtunities. You can use a standard clay, CLAYTONE-40, a self-dispersing clay like TIXOGEL-ML 250 or a third generation clay like GARAMITE-1958. If there is no problem to reach temperatures over 45°C, RHEOTIX-240 (ADVITROL-100 for NAFTA) is a good choice. We can give you antoher oppurtunity: BYK-430 provides excellent sag control due to pseudoplastic flow behavior and fast viscosity recovery after application. It is a liquid product and very easy to handle.
At the moment, we are developing a new epoxy coating. This coating has contact to drinking water, thus it has to be tested according to KTW guidiance. Do you have additives recommendations for zthis kind of coatings?
In the KTW guideline coatings are listed, which have approval for contact with drinking water. The entire coating has the approval. The seperate raw materials, do not have an approval. That is a difference to FDA 175.300 for example. But there is a positive list, where you can list raw materials. If we produce additives with these "allowed" raw materials, you will have the chance to formulate with these a coating, which will get KTW approval. This list is under permanental actualization. That is why, we cannot give a fixed recommendation here. But we have products, which you can use. If you need information, feel free to contact email@example.com
Our target is to formulate a Polayaspartics top coat, which has a smooth, dull surface. How can we achieve this?
It is a little bit difficult to matt a Polyaspartics coating. Due to the low VOC content, the shrinkage of the coating is very limited. This shrinkage is very important for the matting. That means, you have to use a lot of more matting agent, silica, in your system. By using our DISPERBYK-103, you will have the chance to add very high amounts (>10%) of silica in your system. Additive level is approx. 5-10% solid additive calculated on silica.
We are working on different epoxy top coats for water ballast tanks and coatings. Do you have additives to improve the clenability, or to decrease the dirt pickup?
I can recommend BYK-SILCLEAN 3701. It is an epoxy functional silicon macromer. Due to the epoxy functionality, it will be integrated in the paint matrix and this will lead to permanent effect. Both cleanability and dirt pickup will be influenced positively.
What HAPS (hazardous air pollutants) free dispersing agent(s) would you recommend for an 80-90 NVV system? Pigments are dispersed in the 100 epoxy resins with MAK as solvent. The dispersing agents also need to be able to lower viscosity of grinding paste.
I am looking for a rheology additive for waterbrone anti corrosive primer / direct to metal coating. Could you advise some of your products, which provide sag resistance and do not increase water sensitivity?
For DTM coatings, often an acrylic dispersion is used. All of our OPTIFLO Types are possible to use, not one of them increases water sensitiviy. Here we especially recommend OPTIFLO-T 1000, OPTIFLO-M 2600 VF and OPTIFLO-H 7500 VF. If you use an epoxy system, you can use the same products, but depending on the type of emulsion/dispersion you may have to use greater amounts (up to 5%). Additionally, BYK-425 is a recommendation.
Which is the best additive for waterborne anti-corrosive coatings? Most of the additive I tested had a negative influence on water absorbtion and corrosion protection.
It is true, almost all wetting and dispersing additives have a negative influence on corrosion protection. This is why we developed a completely new one. This is the first wetting and dispersing additive which has no negative influence. Depending on formulation, it may increase the adhesion and thus anti-corrosion properties. It is recommended for all water borne systems: 2 pack PU, alkyd, epoxy and acrylates. At the very moment, this additive is not yet commercial available. If you want to have a sample, or need some more information, feel free to contact Info.BYK@altana.com