TPE Or Silicone Rubber Weather Stripping is a polymer synthetic rubber, is the elastic irreversible impression material. In recent years in the field of medicine widely used, as the impression material is mainly to use its good flexibility, toughness, strength. In addition. TPE Or Silicone Rubber Weather Stripping impression also has good mobility, plasticity, the advantages of small volume shrinkage, take the impression of high accuracy, good chemical stability, and the model material does not react, easy stripping, is the current impression material The ideal class.
Repair: such as porcelain bridge crown, local denture and so on.
Orthodontics: tongue side and transparent correction model equipment, individual mold preparation.
TPE Or Silicone Rubber Weather Stripping formula is how to design, what should be considered?
TPE Or Silicone Rubber Weather Stripping and general general rubber compared to all three categories of TPE Or Silicone Rubber Weather Stripping with the components are relatively simple, hot vulcanization is the case. In addition to raw rubber, the main agent, including reinforcing agent, curing agent and some special additives, generally only 5 to 6 components can be composed of practical formula.
TPE Or Silicone Rubber Weather Stripping formulations should take into account the following points.
(1) TPE Or Silicone Rubber Weather Stripping products are generally used at high temperatures, the mix should be stable at high temperatures, for which, usually use inorganic oxides as reinforcing agent.
(2) TPE Or Silicone Rubber Weather Stripping for the high saturation of raw rubber, usually can not be sulfur vulcanization, and the use of heat curing. Thermal vulcanization is organic peroxide as a vulcanizing agent, so the compound should not contain the peroxide decomposition products with the active substances, otherwise it will affect the curing.
(3) TPE Or Silicone Rubber Weather Stripping in the trace of acid or alkali and other polar chemical reagents under the action of silicone bonds easily lead to cracking and rearrangement, resulting in reduced heat resistance of TPE Or Silicone Rubber Weather Stripping, so the choice of complex agent must take into account them Of the acidity, but also should take into account the decomposition of peroxide products, so as not to affect the performance of vulcanized rubber.
(A) the choice of raw rubber
Design recipe should be based on product performance and conditions of use, with different characteristics of the raw rubber. For the general requirements of the use of TPE Or Silicone Rubber Weather Stripping products in the temperature range of -70 ℃ ~ 250 ℃, can be used vinyl TPE Or Silicone Rubber Weather Stripping; when the use of high temperature requirements (-90 ~ 300 ℃), can be used low silicon Rubber; when the products require high and low temperature and resistance to fuel or solvent, you should use fluoroTPE Or Silicone Rubber Weather Stripping.
(2) vulcanizing agent
The vulcanizing agents used in hot vulcanized TPE Or Silicone Rubber Weather Stripping are organic peroxides, aliphatic azo compounds, inorganic compounds, high energy rays and the like, the most commonly used are organic peroxides. This is because the organic peroxide is generally stable at room temperature, but at a higher curing temperature can be quickly decomposed to produce free radicals, so that TPE Or Silicone Rubber Weather Stripping cross-linking.
Peroxides according to their activity can be divided into two categories. One is a universal type, that is, high activity, for a variety of TPE Or Silicone Rubber Weather Stripping can play a role in vulcanization; the other is a vinyl-specific, that is, low activity, only vinyl-based TPE Or Silicone Rubber Weather Stripping from the vulcanization.
In addition to the above general differences of the two types of peroxides, each peroxide has its own characteristics. Vulcanizing agent BP is the most commonly used vulcanizing agent vulcanizing agent, curing speed, high production efficiency, but not suitable for the production of thick products. Vulcanizing agent DCBP because of its product is not volatile, vulcanization will not produce pressure bubbles, especially suitable for extrusion of hot air continuous vulcanization, but its decomposition temperature is low, easy to cause scorch, compound storage time is short. Vulcanizing agents BP and DCBP are crystalline powder, explosive, for safe operation and dispersion, usually using them dispersed in silicone oil or TPE Or Silicone Rubber Weather Stripping paste, the general content of 50%. The boiling point of the vulcanizing agent is very volatile at 110 ° C. When the compound is stored at room temperature, the vulcanizing agent is volatilized and is preferably used in the form of a molecular sieve as a carrier. The vulcanizing agent DTBP does not react with air or carbon black and can be used in the manufacture of conductive rubber and molded products. The vulcanizing agent DBPMH is similar to DTBP, but it is not volatile at room temperature. Its decomposition products are very volatile and can shorten the two-stage vulcanization time. The vulcanizing agent DCP is not volatile at room temperature, has the characteristics of vinyl type, while the decomposition product is also low volatility, can be used for vulcanization of small external pressure occasions. The vulcanizing agent TBPB is used to make sponge products.