Isophorone diisocyanate, polycarbonate diol, dimethylol propionic acid를 출발물질로 하여 제조된 폴리우레탄 prepolymer의 미반응 NCO 기를 실란커플링제인 aminopropyl trietoxysilane (APS)로 capping시켜 수분산 폴리우레탄(waterborne polyurethane dispersion, PUD)을 합성하였다. 그 후 이 PUD에 아크릴 단량체인 2-hydroxyethyl methacrylate와 methyl methacrylate의 혼합물을 첨가하고 중합시켜 silylated acrylic polyurethane dispersion을 제조하였다. 동적 빛 산란법에 의해 측정된 silylated acrylic polyurethane dispersion의 평균 직경은 APS 첨가량이 증가됨에 따라 39.0 nm에서 399.8 nm로 크게 증가하였다. 또한 코팅 도막의 연필경도는 APS의 첨가량이 증가되면서 B에서 F로 향상되었다.
Waterborne polyurethane dispersion (PUD) was synthesized by capping the NCO groups of polyurethane prepolymers, prepared from isophorone diisocyanate, polycarbonate diol and dimethylol propionic acid, with aminopropyl triethoxysilane (APS). Subsequently, silylated acrylic polyurethane dispersion was synthesized by reacting the PUD with the mixture of acrylate monomers, 2-hydroxyethyl methacrylate and methyl methacrylate. The average particle size of silylated acrylic polyurethane dispersion, measured by the dynamic light scattering method, was increased from 39.0 nm to 399.8 nm by increasing the addition amounts of APS. Also, the pencil hardness of coating films of silylated acrylic polyurethane dispersion was enhanced from B grade to F grade with increasing APS content.
