Abstract ▼ AI-Helper

UV-curable polyurethane acrylates for the PVC floor coating have been prepared using non-yellowing polyisocyanates. The effects of the kinds and compositions of prepolymers and diluent monomers have been invesigated on the properties of the UV-curable polyurethance acrylates. Four different types of...

UV-curable polyurethane acrylates for the PVC floor coating have been prepared using non-yellowing polyisocyanates. The effects of the kinds and compositions of prepolymers and diluent monomers have been invesigated on the properties of the UV-curable polyurethance acrylates. Four different types of isocyanates were used to obtain the urethane acrylate prepolymers; isophorone diisocyanate(IPDI) adduct by reacting IPDI and trimethylol propane(TMP), hexamethylene diisocyanate(HDI) adduct by reacting HDI and TMP, HDI biuret, and HDI isocyanurate. Several types of hydroxy acrylates and diluent monomers were used; For hydroxy acrylate, hydroxy propyl acrylate(HPA), polycaprolacton modified hydroxy ethyl acrylate(PCMHEA) were used and for diluent monomers, 2-ethyl hexyl acrylate(2-EHA), hexane diol diacrylate(HDDA), and polyethylene glycol #400 diacrylate(PEG #400 DA) were used. Properties measured include hardness, tensile properties, adhesion properties, viscosity, gel contents, and dynamic mechanical properties. The best coating properties such as low viscosity, high hardness, high tensile strength and modulus, good adhesion to substrate, good thermal resistance and accelerated weather resistance were observed when the HDI isocyanurate type was used as a polyisocyanate for the urethane acrylate prepoymer. The urethane acrylate prepolyrner prepared with the equimolar mixture of HPA and PCMHEA showed best balance coating properties, especially good adhesion, even though the HPA containing urethane acrylate prepolymer showed relatively good general properties such as hardness, tensile strength as well as viscosity behavior except the adhesion property. The urethane acrylate Containing HDDA as a diluent monomer showed good general properties for coating but its elongation property is very poor. The urethane acrylate containing 2-EHA showed bad compatibility. It was concluded that the urethane acrylate containing the PEG #400 DA as a diluent monomer showed fairly good tensile modulus, adhesion, and stainnig resistance. In this case, the adhesion was best with appropriate viscosity(below 150 poise at 25℃) as the PVC floor coating when 35% of the diluent monomer was used. The dynamic mechanical studies showed that the polyurethane acrylates prepared from IPDI showed highest glass transition temperature(Tg), whereas those from HDI showed lowest Tg. The properties of those Polyurethane acrylates with various hydroxy acrylates and diluent monomers were well correlated with their Tg behaviors. In the case of diluent monomers, the polyurethane acrylates prepared from HDDA showed generally good properties but bad flexibility(elongation), whereas those prepared from 2EHA, the bad compatibility of the diluent was shown to be a serious drawback to be applicable for practical use. It was concluded that the pslyurethance acrylates from PEG #400 DA showed most balanced properties for practical uses. The optimum properties in terms of adhesion, and stainning resistance, and viscosity behavior was given when 35% of PEG #400 DA was used as a diluent monomer for the UV-curable polyurethane acrylates.

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