高固体分涂料用含羟基星形丙烯酸酯树脂的制备及性能

Preparation and properties of hydroxyl functionalized star acrylic resin for high solid coating

以占单体物质的量0.01%的低铜盐用量催化剂体系进行电子转移活化再生催化剂原子转移自由基聚合(ARGET ATRP),制备了丙烯酸丁酯、甲基丙烯酸甲酯和丙烯酸羟丙酯为单体的线形和六臂星形共聚物。采用折光指数-激光-黏度三检测联用GPC,1H NMR和DSC对聚合物的分子结构、共聚组成和玻璃化转变行为进行了研究。将聚合物配制成涂料用树脂溶液,流变行为研究表明星形聚合物溶液黏度最低。在高固含量时,星形聚合物降低黏度的优势更明显。在适合喷涂施工的黏度下,六臂星形共聚物比普通自由基聚合得到的商品化丙烯酸酯树脂的固含量可提高10%。采用异氰酸酯固化剂固化得到的漆膜性能测试表明,星形聚合物对应清漆的表干时间很短,同时力学性能达到良好水平。

The copolymers of n-butyl acrylate, methyl methacrylate and 2-hydroxypropyl acrylate were prepared by activators regenerated by electron transfer atom transfer radical polymerization（ARGET ATRP）using the hexa-functional and mono-functional initiators and 0.01% low concentration of complex catalyst. The molecular structure, copolymer composition and glass transition behavior of the polymers were characterized by refractive index-multi angle laser light scattering-viscometer triple detection gel permeation chromatography, hydrogen proton nuclear resonance（1H NMR） and differential scanning calorimetry（DSC）, respectively. The obtained polymers were formulated into solutions for coating. Rheology tests revealed that viscosity of star polymers was the lowest. The viscosity decreasing efficiency was more remarkable at high solids contents. Under suitable spray viscosity, the solid content of star copolymer increased by 10% compared with commercial acrylic resin obtained by conventional free radical polymerization. The tack-free time of varnish composed of star polymers and isocyanate curing agent was very short. The mechanical properties of coating film reached a good level.