BYK Additives & Instruments

Automotive Coatings

We are facing the problem of reduced gloss in the above system. Application method --> ABS COMP. --> cond. primer --> 1K acrylic solid base coat (pigment = 30.00 (organic + inorganic colored pigment)) -->2K PU pigmented clear coat (pigment 8.00 (organic + inorganic colored pigment)) --> baking. Please suggest a suitable additive for better gloss and flow of 2K PU pigmented clear coat in 3-coat 1-bake systems.

For CAB-containing base coats I would suggest DISPERBYK-2000 / DISPERBYK-2001 for organic pigments. In case of non CAB-containing systems, the usage of our new DISPERBYK-2155 is recommended for base coats and also for top coats. For further trials, DISPERBYK-161 can also be used in 2K top coat systems. For inorganic pigments it is necessary to use about 7-10 solids on pigments solids, for organic pigments the amount can be up to 40 and more (70-90 for carbon black). If you start to calculate on your system, please keep in mind to use the right amount of additive depending on the pigments you use; if co-grinding, calculate a little bit higher. On the other hand, it might be possible that you get some reaction foam bubbles in your last layer, due to the temperature which is given to cure the 3 layers. In that case reduce the accelerator and use 1-3 BYKETOL-OK on total formulation.
Technical Service Support

I have a problem with some colors with the paint circulation in metallic colors in the paint piping that sends from the paint house to the cabinet application. The color is dark in the angle of 25°.

This issue you're describing seems to be more related to the metallic pigments than anything else. Due to the fact that the paint is constantly pumped round circulation systems, high shear force arises in critical pump systems. These can damage the metallic pigments. If this is definitely your issue, you need to use special aluminum pigments, so-called non-degrading flakes (NDF) which have been developed for particularly aggressive circulation lines from the ECKART company. Sometimes it is only a matter of aluminum flake orientation, which could be solved by the addition of some wax dispersion to achieve an even formation of the aluminum flakes during the application process. Then the incorporation of e.g.CERAFAK 103 or CERAFAK 106 is quite helpful.
Technical Service Support

Please tell me any additive to improve wetting and dipersing of aluminum pigment.

Generally speaking, you could choose one of the following additives for this issue. If you're talking about a solvent-based system, which I presume you are, you can try either our DISPERBYK-162 and/or DISPERBYK-110 at a dosage between 2.0-2.5 (solid on pigment). Another important thing is the orientation of the aluminum flakes to achieve a uniform appearance (avoiding cloudiness). For this, we could propose the following additives: CERAFAK-103, CERAFAK-106, CERAFAK-110, CERATIX-8461, CERATIX-8483 or CERATIX-8466. If you're talking about water-based systems, our recommendation is our DISPERBYK-180 and/or DISPERBYK-192 and, for the orientation, our AQUATIX-8421.
Technical Service Support

Please recommend a good additive for aluminum and pearl.

Due to limited information on your part, I can only give you some general recommendations. Generally speaking, for solvent-based systems you can use our products DISPERBYK-162 or DISPERBYK-110. DISPERBYK-162 is normally the better choice for aluminum pigments. However, for some grades of aluminum,DISPERBYK-110 is the way to go. For pearlescent pigments, in most cases DISPERBYK-110 is the first choice, followed by DISPERBYK-162. Dosage should be around 2-2.5 % (solid on pigment) for aluminum, and 1.5-3 % (solid on pigment) for pearlescent ones. For water-based systems, our suggestion is DISPERBYK-190, DISPERBYK-192 or DISPERBYK-180, depending on the pigments. The amount of usage should be between 2-5 % (solid on solid pigment) for aluminum, and around 5 % (solid on solid pigment) for pearlescent pigments.
Technical Service Support

What do you suggest as sag control for ultra high solid clear coat for car repair? The system is composed of acrylic polyols resins, solvents like ButylAcetate, PMA, SS100 and Butylglicolacetate, and Isocyanate.

For improved sag resistance in the system you mention, you could try the following products: BYK-415, BYK-430, BYK-431. BYK-415 is a solution of a modified urea which gives temperature independent anti sag resistance. BYK-430 (solution of a high molecular urea modified medium-polar polyamide) and BYK-431 (solution of a high molecular urea modified non-polar polyamide) give you pseudoplastic flow behavior, fast viscosity recovery after application, and outstanding anti-sagging properties. Especially at temperature up to 50°C. However, the thickening effect always depends on the polarity of the solvents, therefore I recommend doing trials with all of the proposed additives and keeping the balance between sag resistance and leveling.
Technical Service Support

Which dispersing agent would you recommend for dispersing Novoperm yellow HR70 in a polyester resin with low acid value? We currently use Disp 163 but are having a lot of problems with tension due to poor pigment wetting.

Normally, the DISPERBYK-163 is a useful additive for this pigment. In the case that you talk about a CAB-containing system, you may be better to try using DISPERBYK-2000 or DISPERBYK-2001. To achieve lower mill base viscosity, it is better to add 3-5 % n-Butanol into the mill base. The recommended additive dosage is 15 % additive solid on pigment.
Technical Service Support

What is the best additive for increasing the low shear viscosity of auto polyester putty to prevent settling and sagging without affecting application viscosity?

Thank you for your request. We recommend the combination of two thix agents: fumed silica (such as Aerosil 200) and a derivate of castor oil (such as Luvitix R-RF). The efficiency of the Aerosil can be increased by adding BYK-405. By using our wetting and dispersing additive BYK-W 969 (1 based on filler), you can increase the filler load (depending on your system, 10 to 15%) and the result is a very smooth putty formulation without any settling or sagging problems.
Technical Service Support

One of our customers is not happy with the dispersability of one of our organic phtalocyanine pigment during grinding to make a waterborne paste. I am looking for an additive to improve the pigment dispersability.

Try DISPERBYK-2012 and DISPERBYK-190 first. I recommend using 20-30% of active substance of the wetting and dispersing additive calculated on phthalocyanine pigment. 
Technical Service Support

We develop acrylic polyurethane 2K for the automotive and plastics industry. Our biggest problem is scratch resistance. We already tried 4% of 1291 CERAFLOUR 996, and it was good but not as good as we wish. First, there are still scratches, and secondly, it impairs the metallic effect and the gloss level. Any suggestion?

To improve scratch resistance, try our NANOBYK-3650, NANOBYK-3652 and NANOBYK-3610 with a dosage of 4% delivery form. Please test these additives first without any other surface active addditives. Addition of surface active additive according further tests.

The latest VOC-compliant technology dictates that clear coats are sprayed using a grip coat followed by a full coat of clear. We want to improve the wetting out and flow of the grip coat as this appears to give an orange peel finish to the full coat. Any suggestions as to how we can improve this issue? We currently use BYK-306.

To improve wetting, we recommend that you use "active" silicones which greatly reduce surface tension, such as BYK-306. But if the surface tension is too low, a negative influence on flow (short wave, orange peel) and foam is visible. That means we have to figure out if the poor appearance of the entire system is caused by insufficient substrate wetting or an over-dose of active silicone. I guess you already have tried different dosages of BYK-306? However, if BYK-306 is not strong enough to give a good substrate wetting, try BYK-378 orBYK-3550 (silicon-modified acrylate with very good recoatability properties). They will greatly reduce surface tension.
Technical Service Support

We are using solspere 26000 for grinding of irgazine red and cinquasia violet with Tio2 and we observe viscosity pick-up more than double within 10 days of storage @ 30°C. Please advise a suitable additive to avoid pick-up in viscosity. For this resin, the system is polyester amino.

Please try DISPERBYK-2001 for Irgazine red and Cinquasia violet (calculation: 25% solid additive on pigment). Depending upon the TiO2 that you use, either DISPERBYK-110 (for basic treated TiO2) or DISPERBYK-180 (for acidic treated TiO2) is the best choice (1.5% solid additive on TiO2). If this is a co-grind (grinding all pigments together), calculate for each individual pigment and add the amount of wetting and dispersing additive accordingly.
Technical Service Support

We recently made a 0.05% adjustment of BYK-320 to one of our automotive clear coats. It is a 1K polyurethane-melamine type coating. We had made this adjustment 5 times previous to this with no defects. This time it resulted in severe craters / fisheyes. The only difference was the temperature of the BYK-320. It normally is the same temperature of the clear (30 deg C) - this time it was 5-10°C. Do you have any documentation on this effect?

The temperature of clear coat and additive has a strong influence on the efficiency of incorporation, which again can cause severe surface disease. Higher temperature improves incorporation and lower temperature leads to a less homogenous distribution of the additive in the clear coat. Obviously, BYK-320 is on the borderline of compatibility in your system, so that an insufficient incorporation shows craters / fisheyes. This effect should be reversible by warming up the clear coat and stirring for a certain time. For the future it is recommended to pre-dilute BYK-320 with solvent to improve incorporation. Please contact me again, if this effect is not reversible.
Technical Service Support

Universal pastes based on Laropal A 81 + DISPERBYK 163 or DISPERBYK 161 are used in a mix system to produce final automotive metalic base coat for automotive refinish paint. The base coats consist of: 22-28% Uracron CR 226 XB50 24-29% of CAB 551-02 25% in BAc and max 20% of universal pigment pastes combinations - including Al or mica etc. Producing metallic base coats most of the shades show no problem. If there is CINQUASIA violet R NRT 201D and/or IRGAZIN blue A3RN / HOSTAPERM BLUE RL-01 in the pigment combination, we often but not always see flocculation in the stage of mixing components into the final base coat. Can you suggest a solution for such a problem? If there is no solution to stabilize these universal pastes so that they can be used in the polar system of metalic base coat, please suggest the formulation of pastes of Cinquasia violet R Nrt 201D and Indanthrons based on acrylic resin. Thank you very much for your prompt reply.

The phenomenon that you are describing is very well known in the base coat area. CAB often causes a problem, even so the pigments are well stabilized. There are two major points that you have to take care of: the pigment stabilization itself. For Irgazin Blue, I would recommend using 15% DISPERBYK-110 (solid additive on pigment), for Violet I, would recommend that you use 25% of DISPERBYK-2000 or DISPERBYK-2001. Unfortunately I cannot tell you which one will be the better choice, since this is very system-dependant. I would try DISPERBYK-2001 first. All three additives mentioned provide a better stability when CAB is added. Secondly, make sure that the CAB solution is added under higher shear forces (high-speed dissolver). A low incorporation speed (i.e. by stirrer) is often the reason for a reflocculation. A higher viscosity of the pigment concentrate before addition of CAB also helps to create higher shear forces. These suggestions should give you the results you are looking for.
Technical Service Support

We face some problem with 2-pack MDI cured acrylated polyol system while it is drying. Wavering and gloss reduction occured simultaneously. How can we prevent this? At present we are using TEGO Glide-410.Pl. Please suggest which type of additive we may use from your existing list of products.

Unfortunately it is not totally clear based upon your comments whether it is a pigmented system or a clear coat. Poor flow and leveling often leads to gloss reduction. Assuming it is a clear coat, you should check whether all the components used in your formulation are compatible with each other (a good indication is checking haze of the dried film in a tin can). If this is the case, please try 0.05% of BYK-378 in combination with 0.5% BYK-358 N. If it is a pigmented system, a wetting and dispersing additive will help: For inorganic pigments please use DISPERBYK-110, for organic pigments use DISPERBYK-161.
Technical Service Support

I have been asked to recommend a dispersion agent for a high surface area carbon black in a solvent-based automotive top coat. Have you any recommendations to pass on?

We recommend the use of DISPERBYK-2000, DISPERBYK-2001 in base coat systems with a level of 70% additive solid on pigment and for top coats DISPERBYK-161 can be used at the same level of addition. 
Technical Service Support

I have problems with my water-borne pigment concentrates especially with carbon black. For certain reasons I have to add some thickener and cosolvent.

DISPERBYK-2012 is our first choice for resin-containing pigment grinds for both waterreducibles and emulsions. Slurry grind allows presence of amine, thickener, surfactant and co-solvent. DISPERBYK-2012 provides good stabilization of a wide range of pigments, mainly transparent and opaque organic pigments. With carbon blacks high jetness can be achieved. There is no negative impact on stability of pH-sensitive systems.