How much should be added to the PP flame - retardant board to reach the V0 level?

The so-called V0 level is a kind of grade standard for the flame retardancy of plastics, which increases gradually from HB, V-2, V-1 to V-0: 

HB: It is the lowest flame retardant grade in the UL94 standard. For samples with a thickness of 3 to 13 millimeters, the burning rate should be less than 40 millimeters per minute; for samples with a thickness of less than 3 millimeters, the burning rate should be less than 70 millimeters per minute; or the sample should extinguish before reaching the 100-millimeter mark.

V-2: After two 10-second combustion tests on the sample, the flame extinguishes within 60 seconds. There can be combustion products falling off. 

V-1: After two 10-second combustion tests on the sample, the flame extinguishes within 60 seconds. There should be no combustion products falling off. 

V-0: After two 10-second combustion tests on the sample, the flame extinguishes within 30 seconds. There should be no combustion products falling off. It is not difficult to see from this that V0 has high requirements in the flame retardant grade. 

Generally, for the flame retardant masterbatch used on PP plates, 8 to 12 parts need to be added to achieve the effect of extinguishing the flame as soon as the heat source is removed. At present, there are not many products that meet the V0 requirements.