Low-gloss powder coating formulation design ideas

At present, the application range of low-gloss powder coatings expanded, production, variety increased, in the design of low-gloss powder coating formulation, first according to customer requirements to determine the film system, and then consider the following four aspects:
1, the addition of filler
with the effect of de-lighting.
gloss ranges from 50-70 degrees. For example, the addition of anti-light sulphate, ultra-fine kaolin, ultra-fine silicon micro-powder, ultra-fine mica powder and other

. This method of lighting has certain limitations, fillers add more coating appearance is not good, plus less lighting effect is poor. This method is suitable for all varieties of powder coatings.
, add additives with anti-light effect.commonly used anti-lighting agents are wax and resin. Wax-type added powder coating dry powder flow is not good, coating surface easy to form waxy fog shadow; Although the resin-type anti-lighting agent does not have the same disadvantages as wax-type anti-lighting agent, but added more film impact strength and other physical and mechanical properties are not good, but also have certain limitations. Powder coatings of various resin types have corresponding types of detergents. Hubei Reiss company's 641/651 series corresponds to the ring polyester, pure polyester system. 641 recommended addition of 1 to 4%, gloss in 5 to 30% adjustment, characterized by good flatness, coating surface is not easy to stick handprint. 651 plus 1 to 4%, gloss can be reduced to 20 to 45%, characterized by baking is not yellowing, weather resistance is good. In addition, there is a light-reducing powder 621 that can be used to make a light coating to simplify the re-production process, with a recommended addition of no more than 1%.
, add anti-light curing agent to the formula.This anti-light method in the epoxy and epoxy-polyester system of the wide range of light, adjustment of coating film gloss is relatively easy, coating appearance of the flatness is better, from the paint cost considerations, with fillers and detergents can not achieve the desired gloss, the formula design can consider the use of anti-light curing agent. Hubei Reiss anti-light agent 631, is a end epoxy-based acrylic resin, used for low acid polyester de-curing, anti-light curing agent will participate in the curing reaction between the system, so you can change the amount of 631 and TGIC To adjust the gloss, 631 usually with the resin ratio of 1:3, the addition between 9 to 12%, the gloss between 1 to 20% regulation, coating film flat, good scratch resistance, high gloss stability.
mixture of two powder coatings with different reaction activity.this method is low cost, but the resulting coating appearance fineness is not as good as the conventional process, coating film resistance is not good, and coating film gloss range is relatively narrow. Therefore, in the design of dry mixed anti-light system, the main attention to the following points:
(1) as far as possible to ensure that the two components of the charged performance of the same
(2) two components in extrusion with their own extruded polyester fully clearing machine, to avoid some residual groups Sub-advance reaction, gloss instability
(3) extruder temperature control should not be too high, high temperature prone to the phenomenon of luster is not soft, the phenomenon of poor leveling
(4) to ensure the consistency of the two groups of crush particle size, but also conducive to the stability of gloss.
according to the above ideas of the formula, in the production process should also pay attention to process control. Mixing different materials, the effect will be different. As well as in different seasons of storage stability, powder spraying construction of the powder rate and powder yield, such as a series of convenience and economy. Therefore, the final formulation and specific production process, need to be at the same time small test and pilot testing, as well as the actual testing of the coating will be feedback to large-scale production, until the actual spray application of the approval.
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