Rubber production process commonly used to promote the match agent
There are thousands of compounding agents for the production of rubber, and their role in rubber is also very complex, not only determines the physical and mechanical properties of vulcanized rubber a
There are thousands of compounding agents for the production of rubber, and their role in rubber is also very complex, not only determines the physical and mechanical properties of vulcanized rubber and product performance and life, but also affect the process of processing materials And the quality of semi-finished products processing, with a different agent in the role of different raw rubber is not the same, different agents in the same raw rubber from the role of different, even the same agent in the same rubber in the role played by more than One. Therefore, we can only according to the main role of the compound in the rubber they are divided into curing agent, vulcanization accelerator, curing agent active agent, antioxidant, anti-scorching agent, reinforcing filler softening plasticizer, other special cooperation Agent and so on.
Vulcanizing agent: Anything that can be vulcanized with rubber or cross-linked substances collectively referred to as vulcanizing agent, also known as cross-linking agent.
There are many types of vulcanizing agents, and they are still increasing. The vulcanizing agents which have been used are sulfur, selenium, tellurium, sulfur compounds, metal oxides, peroxides, resins, quinones and amines.
Since the invention of rubber vulcanization so far, sulfur has been a natural rubber and most of the diene general synthetic rubber vulcanizing agent, although the emergence of many new vulcanizing agent to improve the performance of rubber products played a significant full use, But the price is generally more expensive, it is still the main sulfur. Metal oxides are chlorinated rubber special curing agent, in addition to selenium, tellurium, the other non-sulfur compounds vulcanizing agent is mainly used for saturated rubber and special synthetic rubber vulcanization, the most important is the peroxide.
Where the material can speed up the curing reaction speed, shorten the curing time, reduce the curing temperature, reduce the amount of vulcanizing agent, and can improve or improve the physical properties of vulcanized rubber substances collectively referred to as vulcanization accelerator, referred to as accelerator.
The accelerator can also improve the vulcanization productivity and the vulcanization quality, so that the degree of vulcanization of the thick product is uniform and the product cost is reduced. Many types of accelerators used in the rubber industry, according to their chemical composition and nature can be divided into two categories, inorganic accelerator and organic accelerator. At present, in addition to individual circumstances, are generally used are organic accelerator. Because of its large effect of promoting, vulcanization characteristics, vulcanized rubber physical and mechanical properties of excellent, rapid development, a wide range.
According to the chemical structure of the accelerator is usually divided into eight categories: thiazoles, thiuram class, sulfenamides, guanidines, dithiocarbamates, aldehydes, xanthates and sulfur Urea.
With the accelerator M as the standard can be divided into super-speed, over-speed, quasi-over-speed, medium speed and slow speed several types. Internationally used to promote the agent M (mercaptobenzothiazole) as the standard, where the vulcanization speed is faster than M belonging to the speed or ultra-speed level, the vulcanization rate is lower than M are medium or slow speed, curing speed is equal to or close to M Belong to quasi-speeding level. Natural rubber and most synthetic rubber used in the accelerator are used in the classification.
The accelerator can be classified according to the acidity and alkalinity, where the acid or hydrogen sulfide reaction to produce acidic products are acid accelerators, such as thiazoles, thiuram, dithiocarbamates and xanthates Class; itself is alkaline or hydrogen sulfide after the reaction of alkaline products are alkaline promoters, such as guanidine, aldehydes and amines; both conditions were neutral neutral promoter, Such as sulfonamides and thioureas. This classification is used in the case of production or accelerator.
In the system of accelerators, there should be a scavenger which is the main promoter, also known as the main accelerator, also known as the first accelerator, while the other one or two are auxiliary, called the auxiliary accelerator, also known as the first Two, three accelerators.
Activated agent, activator, promoter. It is involved in the vulcanization of rubber, improve the activity of accelerator and give full play to its effectiveness, reduce the amount of accelerator, both to improve the rate of curing, but also improve the degree of cross-linking, cross-linked structure to improve the physical properties of vulcanized rubber. There are many types of vulcanizing agents for rubber. Divided into inorganic and organic two categories. The most commonly used is zinc oxide and stearic acid and use. The amount of 35 and 1.5-2.0 copies. Zinc oxide also has some reinforcing effect on natural rubber. Stearic acid on the rubber and softening plasticizing effect, to help the mixed dispersion of carbon black.
Protection system with agent
Rubber and its products in the storage and use of the process, due to the role of various external factors, such as heat, oxygen, ozone, variable metal ions, mechanical force, light, high-energy radiation, chemical substances and mold role, Physical and mechanical properties and performance will gradually decline, the gradual loss of flexibility and the use of value, this phenomenon is called aging. In order to extend the service life of the product, certain substances must be added to the rubber to inhibit or delay the aging process of the rubber, which is collectively referred to as rubber antioxidant.
A variety of antioxidants, according to the principle of protection is divided into physical antioxidant, chemical antioxidant and reactive antioxidant; according to the protective effect is divided into antioxidants, anti-ozone agent, flexion crack inhibitor, harmful metal inhibitors, Agent and so on.