There are thousands of compounding agents used in the production of rubber, and their role in rubber is also very complex, which not only determines the physical and mechanical properties of the vulcanizate and the performance and life of the product, but also affects the processing performance of the rubber compound. Compared with the processing quality of semi-finished products, the same compounding agent plays a different role in different raw rubbers, different compounding agents play different roles in the same raw rubber, and even the same compounding agent plays a role in the same rubber. one. Therefore, we can only divide them into vulcanizing agents, vulcanization accelerators, vulcanizing agent active agents, anti-aging agents, anti-scorch agents, reinforcing fillers, softening plasticizers, and other special compounds according to their main roles in rubber. agent, etc.

Vulcanizing agent: All substances that can react with rubber or make it cross-link are collectively called vulcanizing agent, also known as cross-linking agent.

There are many types of vulcanizing agents, and they are still increasing. The vulcanizing agents that have been used include sulfur, selenium, tellurium, sulfur-containing compounds, metal oxides, peroxides, resins, quinones and amines.

Since the invention of vulcanization of rubber, sulfur has been the main vulcanizing agent for natural rubber and most general-purpose synthetic rubbers of diene type, although the emergence of many new vulcanizing agents has played a significant role in improving the performance of rubber products. But the price is generally more expensive, so it is still dominated by sulfur. Metal oxides are special vulcanizing agents for chloroprene rubber. Except for selenium and tellurium, other non-sulfur compound vulcanizing agents are mainly used for the vulcanization of saturated rubber and special synthetic rubber. The most important thing is peroxide.

Vulcanization accelerator

All substances in the rubber compound that can speed up the vulcanization reaction, shorten the vulcanization time, reduce the vulcanization temperature, reduce the amount of the vulcanizing agent, and can improve or improve the physical and mechanical properties of the vulcanizate are collectively referred to as vulcanization accelerators, referred to as accelerators.

Accelerators can also improve vulcanization production efficiency and vulcanizate quality, make thick products evenly vulcanized, and reduce product costs. There are many kinds of accelerators used in the rubber industry, which can be divided into two categories according to their chemical composition and properties, inorganic accelerators and organic accelerators. At present, except for a few cases, organic accelerators are generally used. Due to its large promoting effect and good vulcanization characteristics, the physical and mechanical properties of vulcanizate are excellent, and it develops rapidly and has a wide variety.

According to the chemical structure of accelerators, they are usually divided into 8 categories: thiazoles, thiurams, sulfenamides, guanidines, dithiocarbamates, aldamines, xanthates and sulfur Ureas.

Taking the accelerator M as the standard, it can be divided into several types: super-super-speed, super-speed, quasi-super-speed, medium-speed and slow-speed. Internationally, it is customary to use accelerator M (mercaptobenzothiazole) as the standard. Those with a vulcanization speed faster than M belong to the super-speed or ultra-super-speed grade, and those with a vulcanization speed lower than M belong to the medium-speed or slow-speed grade, and the vulcanization speed is equal to or close to M. Those belong to the quasi-overspeed class. This classification is used for accelerators used in natural rubber and most synthetic rubbers.

Accelerators can be classified according to acidity and alkalinity. Those that are acidic or react with hydrogen sulfide to generate acidic products are acidic accelerators, such as thiazoles, thiurams, dithiocarbamates and xanthates. Alkaline accelerators, such as guanidines, aldehyde amines and amines, which are alkaline by themselves or whose products reacted with hydrogen sulfide are alkaline; neutral accelerators that are neutral under both conditions, Such as sulfenamides and thioureas. This classification is mostly used in the case of production or the use of accelerators.

In the system of accelerators, one of them should be the main accelerator, which is called the main accelerator, also called the first accelerator, and the other one or two are auxiliary, which is called the secondary accelerator, also called the first accelerator. Two and three accelerators.

Active agent

Vulcanization activator is referred to as activator, activator, and auxiliary accelerator. It participates in the vulcanization reaction of rubber, improves the activity of the accelerator and gives full play to its effectiveness, reduces the amount of the accelerator, not only increases the vulcanization speed, but also increases the degree of cross-linking, affects the cross-linking structure and improves the physical and mechanical properties of the vulcanizate. There are many types of vulcanization activators for rubber. Divided into inorganic and organic categories. The most commonly used combination is zinc oxide and stearic acid. The dosage is 35 parts and 1.5-2.0 parts respectively. Zinc oxide also has a certain reinforcing effect on natural rubber. Stearic acid also has a softening and plasticizing effect on the rubber compound, helping to mix and disperse carbon black.

Compounding agent for protective system

In the process of storage and use, rubber and its products are affected by various external factors, such as heat, oxygen, ozone, metal ions with variable valence, mechanical force, light, high-energy rays, chemical substances and molds. The physical and mechanical properties and use performance will gradually decline, and gradually lose elasticity and use value, this phenomenon is called aging. In order to prolong the service life of the product, certain substances must be added to the rubber to inhibit or delay the aging process of the rubber. These substances are collectively referred to as rubber antioxidants.

There are many kinds of antioxidants, which are divided into physical antioxidants, chemical antioxidants and reactive antioxidants according to the protection principle; antioxidants, antiozonants, flex crack inhibitors, harmful metal inhibitors, ultraviolet absorption agents according to their protective effects agent, etc.