Polymerization of Oriental Lacquer (Urushi) with Epoxidized Linseed Oil as a New Reactive Diluent

Table 2

Polymerization of lacquer paints with epoxidized linseed oil ELO-6.

	Paint^a			Polymerization time^b		Polymerization film after 7 days^c
Number	ELO-6		Viscosity	TF	HD	Pencil	Color scale			Gloss		Weight loss at 20%	Residue at 600°C
			mPa·s	h		hardness				60°	°C	°C	%
1	KL	—	4598	4.4	8.6	HB	3.41	13.00	4.41	88.5	90.1	406	0.8
2	KL	◯	2382	2.3	3.8	F	1.39	5.42	1.78	84.3	95.5	377	17.7
3	HBL	—	25476	1.2	2.0	F	0.95	0.61	0.56	76.2	101.8	419	29.6
4	HBL	◯	12841	1.1	2.0	F	0.59	0.38	9.47	86.9	131.8	380	28.7

The KL (kurome lacquer) and HBL (hybrid lacquer) paints with ELO-6 (6.4 mol% epoxidation) were prepared in the weight proportions as follows.
KL: EOL-6 = 10 : 1 for number 2, KL: hydrolyzed AATES = 10 : 1 for number 3, and KL : hydrolyzed AATES : ELO-6 = 10 : 1 : 0.25 for number 4, respectively.
Viscosity was measured by the DV-II+ viscometer at room temperature.
^bPolymerization time was measured by touch-free (TF) polymerization state and hard (HD) polymerization state under 20–25°C at 55–60% humidity.
^cPencil hardness was recorded by the JIS-K 5400 drying recorder. Color scale was measured by the BYK-Gardner according to the spectro-guide 45/0.
means brightness, means +red/−green, and means +yellow/−blue, respectively. The gloss (60°) of polymerized film was obtained by the PG-1M glossmeter.
The glass transition temperature () measurement was carried out with the RPT-3000W rigid-body pendulum-testing (RPT) machine.
Temperature of weight loss at 20 wt% and residue at 600°C were recorded by the DTG-60 thermoanalyser at the heating rate of 10°C under N₂ atmosphere.