1 Medium weight gain test

Samples can be taken from the finished product, soaked in one or several selected media, weighed after a certain temperature time, and the type of material can be inferred according to the rate of change of weight and hardness.

For example, after soaking in 100 degree oil for 24 hours, NBR, fluorine glue, ECO, CR quality and hardness change rate is very small, while NR, EPDM, SBR weight increase more than double and hardness change greatly, volume expansion is obvious.

2 Hot Air aging experiment

Take a sample from the finished product, put it in the aging box for one day, and observe the phenomenon after aging. Can be graded aging gradually heating up. For example, CR, NR, SBR will be brittle at 150 degrees, and NBR EPDM will be elastic. Normal NBR will brittle at 180 degrees; The HNBR will also be brittle at 230 degrees, and the fluorine glue and silica gel still have good elasticity.

3 Combustion method

Take a small sample and burn it in the air. Observe the phenomenon.

Generally speaking, fluorine glue, CR, CSM from the fire breath, even if the fire is much smaller than the general NR, EPDM. Of course, if you look closely, the burning state, color, smell will also give us a lot of information. For example, NBR/pvc and glue, when there is a fire source, the fire splashes, seems to have water, from the fire to extinguish, the smoke is thick and sour. It should be noted that sometimes the glue that is added with flame retardants but does not contain halogens will also extinguish itself from the fire, which should be further inferred by other means.

4 Specific gravity

Use an electronic scale or analytical balance, accurate to 0.01 grams, plus a glass of water, a hair can be.

Generally speaking, the proportion of fluorine glue is the largest, more than 1.8, CR ECO is also more than 1.3, the proportion is obviously too large can be considered these glue.

5 Low temperature method

Take samples from the finished product and create a suitable low temperature environment with dry ice and alcohol. Soak the sample in a low temperature environment for 2-5 minutes, and feel the degree of hardness at the selected temperature. For example, at -40 degrees, the same high temperature and oil resistance is very good compared with fluorine rubber, silicone is relatively soft.