The following precautions on the use of PU color paste can reduce the negative impact of color paste on polyurethane foaming.
1. Convert the color paste to the amount of polyether, but it cannot be completely regarded as polyether, because the two OHs are not necessarily the same. It may be that the ratio of NCO to OH is wrong. First of all, we must solve this ratio. The carrier of the color paste also contains OH, which means that the more the color paste is added, the ratio of OH/NCO will be wrong, and the bubbles will be It is soft, the density is not right, it may collapse, the color paste is added high, and the amount of NCO needs to be increased accordingly. This can be calculated according to the formula.
2. Control the amount of color paste, generally it will be better if it is below 2%, or use 3 parts of color paste.
3. Contact the color paste manufacturer, ask the color paste supplier’s color paste material safety data sheet, check the exact main chemical composition of the color paste, judge whether it is a reactive or filling type color paste, or the proportion of each item, and Estimate the effect of color paste on the overall reaction system and physical properties. When providing special color paste, the content of color essence (color masterbatch) is higher, and it does not matter if the price is a little higher, as long as it is easy to operate.
4. The last point is very simple but easily overlooked: the type of color paste, and the selection of color paste for different products is different. The above can be regarded as some tips on the use of color paste, and it can also be regarded as a rescue method for the negative effects of color paste.
