Compared to water-based coatings, UV-curable coatings are difficult to mattify. The ability to matte depends on the nature of the formulation, the reactivity of the resin, and the curing conditions. Generally, low reactivity and slow curing conditions favor extinction, while highly reactive curing systems are difficult to extinguish. The vast majority of UV-curable coating systems for matting agent requirements should not affect the viscosity of the system, so the oil absorption of silica should be as small as possible.
The manufacturing process of this matting agent is different from the traditional sense of silica matting agent. At the same time, the oil-absorbing amount of small matting agent often pile specific gravity is larger, easy to precipitate, subject to special treatment before use.
Unsaturated polyester UV-curable coatings are relatively easy to matte, and the traditional matting agent mechanism is the same. Acrylic UV-curable coatings and the opposite of traditional coating systems, often organic treatment as well as small particle size matting agent has a better matting effect. If there are components in the coating formulation that may accelerate surface curing, it is more difficult to matte.
The adsorption form of the polymer wetting and dispersing agent. They are adsorbed on the surface of pigment particles through functional groups and polymer anchor chains. It is adsorbed by functional groups, and is adsorbed on the surface of the pigment particles by the special anchor group of the polymer wetting and dispersing agent.
(a) Random copolymer (b) Monofunctional polymer at one end (c) Polymer with double functional group
Ring, tooth, tail-shaped adsorption, single-point tail-shaped adsorption, double-point adsorption at both ends, one ring is stretched out
(d) ABA block copolymer (e) BAB block copolymer at both ends (f) graft copolymer
Anchor base is adsorbed, and the double-tailed anchor base is adsorbed, and a ring comb is adsorbed.
(g) AB type block copolymer (h) mid-terminal monofunctional polymer (i) polymer compound
One end anchored adsorption, extended single tail, single point adsorption, extended double tail flat adsorption
Straight chain horizontal adsorption (k) Straight chain vertical adsorption
Polymer wetting and dispersing agent and adsorption morphology of polymer compounds
In solvent-based coatings, the stabilizing effect of steric hindrance is mainly due to byk amide wax entropy repulsion. The secondary chain that constitutes steric hindrance must have a certain length and a certain degree of freedom of movement. According to these requirements, there must be a certain number of adsorption groups in the molecule, and as a free-moving stretch base, the chain links are preferably tail-shaped. However, (b) and (h) are both single-point adsorption, and the fastness is not strong. It is best to block copolymers of ABA type compounds and graft copolymers.
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