The molding characteristics of several common rubber
1: natural rubber:
Natural rubber are more likely to win the plasticity. Constant viscosity and low viscosity standard horizontal injection molding machineshuo laiz Malay west pressure rubber with low initial viscosity, generally do not need the molding. If other models of standard rubber Mooney viscosity greater than 60, still need the molding.
Natural rubber mixing mill plasticate, roller temperature of 30 ℃ and 40 ℃, time of about 15-20 min. When using a mixer plasticate, when the temperature is above 120 ℃, for about 3-5 min. When adding plasticizer or plastic solution agent, can significantly shorten the molding time, improve the effect of plastication.
2: styrene-butadiene rubber:
Generally speaking, the Mooney viscosity of styrene-butadiene rubber between 35 to 60. So the styrene-butadiene rubber can also need not plastication. But actually after plasticate, can improve the dispersivity of the chelating agent, help to improve the quality of the product. Especially the sponge rubber, styrene-butadiene rubber after plasticate, easy to foam and bubble hole size uniform.
3: butadiene rubber:
Butadiene rubber has the cold flow property, it is not easy to improve the effect of plastication. Butadiene rubber Mooney viscosity of the currently used in the polymerization has the control in the appropriate range (5 ° to 45 ° +), therefore, generally do not need to plasticate directly mixing.
Plasticate neoprene generally don't have to, but toughness is bigger, because the gel mixing with mixing mill BoTong before 3-5 times, help to operate, BoTong temperature of 30 ℃ and 40 ℃, high sticking easily.
5: ethylene propylene rubber:
Ethylene propylene rubber as the main chain of the molecule is saturated structure, the molding difficult to cause the molecule's cracking. Therefore, should be through the synthesis has the appropriate Mooney viscosity without plastication.
6: butyl rubber:
Butyl rubber because of its stable chemical structure and soft, and smaller molecular weight, liquidity is big, so the mechanical plasticizing effect is not big. Low Mooney viscosity of butyl rubber is generally not required to pass through the molding can directly mixing, high Mooney viscosity of butyl rubber high temperature chemical plasticate method can be applied.
7: nitrile rubber:
Small nitrile rubber plasticity, toughness, and plastication hot big, therefore, usually in the mixing machine adopts low temperature (temperature below 40 ℃), small roller distance (about 1 mm), low volume (70% of the natural rubber) and the piecewise plasticate, which can receive good effect. Nitrile rubber unfavorable use mixer plastication. Soft NBR because itself has certain plasticity (usually less than 60 °), so it can not plasticate, directly mixing.