How To Identify The Specific Material Of Rubber Products

1. Resistance to medium weight gain experiment

Samples can be taken from the purchased O-rings. After the temperature is determined, they are immersed in the selected medium or media, and weighed after a certain period of time. The type of material is inferred based on the rate of change of weight and the rate of change in hardness. For example, immersing in 100 degree oil for 24 hours, Dingqing, fluorine rubber, chloroprene quality and hardness change rate is very small, while natural rubber, EPDM gain more than doubled and hardness changes greatly, volume expansion is obvious.

2, combustion method

Samples were taken and burned in air. Observe the phenomenon. In general, fluorine rubber, natural rubber will be destroyed after the fire, even if the flame is burning, it is much smaller than the EPDM. Of course, if you look closely, the burning state, color, and smell will provide us with a lot of information. For example, NBR/PVC is glued together. When there is a fire source, there is a splash of fire. It seems to have water. It is self-extinguishing from the fire, and the smoke is rich and sour. It should be noted that sometimes the flame retardant but halogen-free glue will also be self-extinguishing from the fire, which is further inferred by other means.

3, hot air aging experiment

Samples were taken and aged in an aging chamber for one day to observe the phenomenon after aging. In order to be able to grade aging, it can be gradually warmed up. For example, 150 degrees under the chloroprene, natural rubber, SBR will be brittle, Ding Qing, EPDM and elasticity. When it rises to 180 degrees, ordinary Dingqing will be brittle; at 230 degrees, hydrogenated nitrile will also be brittle, and fluorine rubber and silica gel still have good elasticity.

4, low temperature method

Samples are taken and a suitable low temperature environment is made with dry ice and alcohol. The sample was soaked in a low temperature environment for 2-5 minutes, and the softness and hardness of the O-ring was felt at the selected temperature. For example, at -40 ° C, the same high temperature and oil resistance is very good compared to silica gel and fluorine rubber, silica gel will be softer.

5. Measuring specific gravity

Use a precision electronic scale, add a glass of water, a hair can be. In general, the specific gravity of fluorine rubber is 1.8 or more, and the CR and ECO are also more than 1.3. These rubbers can be considered as the specific gravity is too large.