Table 1. Design of 3-Layered PVC Sheet by Varying the Plasticizer, Additives, and Surface Treatment

	Plasticizer		Additives	Primer	Surface Coating
	DINP	DOA	Additives	Primer	Surface Coating
1^st-developed	50	-	-	-	Water-based urethane (2 components)
2^nd-developed	60	-	UV absorber antioxidant	acrylic	Water-based urethane (2 components)
3^rd-developed	55	-			Water-based urethane (2 components)
4^th-developed	47	3			Water-based urethane (2 components)
5^th-developed	50	5			Oil-based urethane (1 component)