Table 1. Formulation of the NR Compounds according to Petroleum Resin Content

	VDR-1	VDR-2	VDR-3	VDR-4
NR	100	100	100	100
Zinc oxide	5	5	5	5
Stearic acid	1	1	1	1
Carbon black	70	70	70	70
Aromatic oil	5	5	5	5
Petroleum resin	0	10	15	20
Anti oxidants	6	6	6	6
Sulfur	2	2	2	2
CBS	1	1	1	1
Total	190	200	205	210