In the production process of silicone rubber products, sometimes it is necessary to identify silicone rubber raw materials. What are the commonly used methods for identifying silicone rubber? Let's share the five most common methods.
1, the combustion method, first take a small amount of product, after burning. Fluorine glue generally burns up in general, while CR and CSM are extinguished without fire support. NR and EPDM burn more flames. In addition, you can also carefully observe the burning state, color, and smell. For example, NBR/PVC is glued together. When there is a fire source, it will splash and ignite. After leaving the fire, it will self-extinguish. The smoke is rich and sour.
Ps: Sometimes a flame retardant but a halogen-free glue will be self-extinguishing from the fire, which is inferred from the actual situation.
2. Measure the weight, take out the sample, use the electronic scale or analytical balance, accurate to 0.01g. It is the easiest to identify the fluorine rubber. Because the weight of the fluorine rubber is the largest, 1.8 or more, CR ECO is also more than 1.3. Large ones can be considered for these glues.
3. The hot air is aged, the sample is taken out, and it is aged for one day in the aging box to observe the phenomenon after aging. Grading aging gradually warms up. At 150 degrees, CR, NR, and SBR will be brittle, and NBR EPDM will be elastic. When it is raised to 180 degrees, ordinary NBR will be brittle; at 230 degrees, HNBR will also be brittle, and fluorine rubber and silica gel still have good elasticity.
4. Under low temperature method, take out the sample and put it into a suitable low temperature environment. The sample was soaked in a low temperature environment for 2-5 minutes and felt soft and hard at the selected temperature. For example, at -40 degrees, the same high temperature and oil resistance is very good, compared with silica gel and fluorine rubber, silica gel is soft.
5. Resistance to medium weight gain, can be sampled from the finished product, immersed in one or several selected media, and weighed after a certain temperature time, and the type of material is inferred according to the rate of change of hardness. Soaking in 100 degree oil for 24 hours, NBR, fluorine rubber, ECO, CR quality and hardness change rate is small, while NR, EPDM, SBR gain more than double the hardness and change greatly, volume expansion is obvious.
To sum up:
Through the above five methods, the silicone rubber raw material can be distinguished, but the actual operation situation is judged at the time, such as the existing configuration and conditions in the silicone product factory, and the appropriate method is selected, so that it can be quickly distinguished, which can save time. And the cost, so that the production efficiency of silicone rubber products can be guaranteed.