Natural rubber can be divided into two categories by form: solid natural rubber (film and granular rubber) and concentrated latex. In daily use, solid natural rubber accounts for the majority of the proportion.

Film according to the different manufacturing process and shape, can be divided into cigarette gum, air-dried film, white wrinkle, brown wrinkle, etc. Cigarette gum is a representative variety of natural rubber, has been a large amount of, widely used rubber, cigarette gum is generally classified according to the shape, divided into special JI, level -, level 2, level 3, level 4, level 5, a total of six, not up to level 5 is listed as the outer rubber.

The physical and chemical properties of the sealing ring manufacturers include impurity content, plastic initial value, plastic retention rate, nitrogen content, volatile content, ash content and color index seven items, among which the impurity content is the dominant indicator, According to the amount of impurities into 5L, 5, 10, 20 and 50 grades.

Liquid silicone futures trading market Shanghai Futures Exchange natural rubber contract delivery grade for domestic - level standard glue SCR5 and imported cigarette gum RSS3, which domestic - level standard glue SCR5 is usually known as no. 5 standard glue, the implementation of the national technical supervision bureau issued the implementation of natural rubber GB/T8081 ~ 1999 version of the quality indicators. RSS3 of imported tobacco flake rubber is implemented in accordance with the "international standard for quality and packaging of natural rubber grade" (Green Book)(1979 edition).

Domestic imports silicone tube using imported raw materials, such as the United States dow corning, Japan more letter, products have passed ROHS, FDA international environmental protection professional test, high temperature yellowing resistance, products after vulcanization transparency nearly transparent, tasteless, after an extrusion sulfide article a silicone cases without secondary plus sulfur, can completely replace platinum vulcanizing agent, and there is no spray frost. It is suitable for extrusion of transparent or color silicone tube, sheet, strip and other high-quality silicon products, which can resist aging or yellowing of light, ultraviolet, heat and water in long-term use. Special note: can be used for precipitation rubber and high tensile force phase method of silicone rubber extrusion hot air vulcanization, no bubbles.

Domestic silica gel tube is slightly worse in performance, lower in tensile resistance, and no domestic imported silica gel strip is bright. The same hardness, domestic imported silica gel tube is better in elasticity.

Appearance color -- translucent (domestic silicone tube), high transparency (domestic imported silicone tube)

Taste -- slight taste (domestic silicone tube), tasteless (domestic imported silicone tube)

Tear resistance -- milky white after stress (domestic silicone tube)

Force does not change color (domestic imported silicone tube)

Advantages of domestic silicone tube:

1. Weak acid and alkali resistance; Ozone resistance; High temperature resistant; Widely used in medical supplies and food rubber polyurethane products factory accessories;

2. Translucent, good elasticity, strong resistance to pulling force; Good extrusion resistance (but not for peristaltic pump);

3. Wide temperature range: about -30~180℃; Medium pressure capacity: 2-3 kg

Advantages of domestic imported silica gel tube:

1. Weak acid and alkali resistance; Ozone resistance; High temperature resistant; Widely used in medical supplies and food supplies accessories;

2. Close to full transparency for easy observation; Elastic wuxi rubber miscellaneous better, stronger tensile force; Better extrusion resistance (peristaltic pump will use imported pipe);

3. Wider temperature range: about -30~250℃; Medium pressure capacity: 2-3 kg