To improve the storage stability, try a lower LAPONITE RD dosage to 2% or 2.5% and add after solving the LAPONITE the same amount of polypropylene glycole to the clear solution. As lower the LAPONITE RD content, as longer the storage stability of the solution. Important is also to work with very purified water which has very low conductivity / ion content.
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.
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.
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 or BYK-3550 (silicon-modified acrylate with very good recoatability properties). They will greatly reduce surface tension.
Thank you for your request. We recommend the combination of two thixotropic agents: hydrophilic fumed silica such as Aerosil 200 in combination with a derivate of castor oil such as RHEOBYK-100 or RHEOBYK-7590. The efficiency of the Aerosil can be increased by adding approx. 20% RHEOBYK-R 605 based on Aerosil.
In amine accelerated putty’s, you can increase the filler load by approx. 10% to 15% by using our wetting and dispersing additive BYK-W 969 with 1% based on filler.
In cobalt accelerated putty’s, you can archive a filler increase of approx. 6% by using 1% BYK-W 966 on filler. If no filler increase is desired, you can only reduce the viscosity with those Additives. The result is a very smooth putty formulation without any settling or sagging problems. In general, the putty with BYK-W 966 exhibits a lower amount of separation.
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
For improved sag resistance in the system you mention, you could try the following products: RHEOBYK-415, RHEOBYK-430,RHEOBYK-431. RHEOBYK-415 is a solution of a modified urea which gives temperature independent anti sag resistance. RHEOBYK-430 (solution of a high molecular urea modified medium-polar polyamide) and RHEOBYK-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.
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-2060, 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.
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 (aromatic free), CERATIX 8561, CERATIX 8583 or CERATIX 8566 (aromatic free). If you're talking about water-based systems, our recommendation is our DISPERBYK-180 and/or DISPERBYK-192 or DISPERYK-2060 and, for the orientation, our AQUATIX-8421 in combination with Laponite-RD.
The additive type is highly depending on the type of pigment used. Our first recommendation would be DISPERBYK-2200, DISPERBYK®-2000, DISPERBYK®-2001. In base coat systems with a level of 70% additive solid on pigment. For top coats we recommend DISPERBYK-2013, DISPERBYK-2200, DISPERBYK-2014 or DISPERBYK®-161with the same level of addition. Also commercially available laboratory products (LP-products) are available, please get in contact with us in case these suggestions would be helpful.
DISPERBYK-2012 and DISPERBYK-2014 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. Both products 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.
First LAPONITE has to be added slowly into demineralized water while stiring. This avoids the formation of gel particles. Also it is importatant only to add the LAPONITE solution as long as it is liquid. Postaddition of polypropylene glycole increases the using time of the LAPONITE solution drastically.
Active silionces like BYK-378 can be used in small quantaties in primer surfacer to improve substrate wetting and anti crater properties as long the primer surfacer is sanded very well. In wet on wet (non-sandable) application the active silicone will lower the surface energy of the dried primer surfacer which cause the wiping marks. For such a application you better use BYK-3550 which lowers the surface tension quite similar to BYK-378 but will not impact the surface energy significant.
The mechanisem for metallic orientation in waterborne is quite different, becasue of the much slower evaperation speed of water. That mean the rheology of the paint is the key mechanisem for the effect pigment orientation. Therefore you need additives which provide pseudoplasticity with certain elastic parts to keep the flaces in the paint orientated. Here I like highly to recommend you to test the AQUATIX 8421. This wax provid you in the right dosage a good rheology profile for metallic orientation. But please keep in mind, that you should not adjust the applicaiton viscosity in flow cup, because this is not the right tool when psneudoplasticity is requisted. The adjustment have to be done with rotation viscosimeter. If higher flop values necessary you can combind the AQUATIX 8421 with Laponite RD.
DISPERBYK-190 is suitable to stabalize a very wide range of products in resin free slurry grind. Also for transparant iron oxides. The issue with this special type of pigments is that they contain iron iones, which cause the gelling of the waterborne resins. When you like to prevent the gelling you can add 1-5% DISPERBYK-102 into the slurry grind in combination with DISPERBYK-190 (approx. 25% additive solid on pigment). Please don't forget to adjust the pH of the slurry to the pH of your paint system before let down.