Prepolymerization of Lacquer Sap under Pure Oxygen Atmosphere and Its Effects on the Properties of Lacquer Film

Table 2

Drying time (h:min) of lacquer films and coating properties of cured films.

Sample	Prepolymerization time (h)	30°C, 78% RH		30°C, 65% RH		Pencil hardness^b	Gloss^b
		TD	HD	TD	HD
RL^a	0	3:20	5:50	23:30	30:20	3H	81
1	0.5 h	2:30	4:30	18:10	26:20	4H	119
2	1.0 h	2:30	4:00	11:20	18:40	4H	118
3	1.5 h	2:20	3:30	9:50	17:10	4H	115
4	2.0 h	1:30	2:50	8:50	15:10	4H	125
5	2.5 h	0:30	2:30	6:40	13:20	4H	109
6	3.0 h	0:40	2:20	5:40	12:30	4H	110

RL: raw lacquer; ^bthe lacquer films were tested after drying at 30°C and 80% RH for two weeks.