Rubber additives cause vulcanization derived from natural rubber. After more than eighty years of research, until the 1920s and 1930s, with the industrialization of the basic varieties of vulcanization accelerators 2-mercaptobenzothiazole and its sulfenamide derivatives, as well as p-phenylenediamine antioxidants, rubber additives The system is basically formed. Rubber additives are in a stable period, and the output of the two main organic additives, vulcanization accelerators and antioxidants, is about 4% of the raw rubber consumption. The production of rubber additives abroad is quite concentrated, with Bayer AG in the Federal Republic of Germany and Monsanto in the United States being the most important manufacturers. The production of rubber additives (referring to organic additives) in China began in 1952.
In the formula, R'is H and R is an organic group; or R'and R are both organic groups; R'and R can also form a ring by the accelerator M or its sodium salt, or by the accelerator DM, and cyclohexane Amine (product is accelerator CZ), dicyclohexylamine (product is accelerator DZ), diisopropylamine (product is accelerator DIBS), morpholine (product is accelerator NOBS), tert-butylamine (product is NS), etc. Manufactured by different processes. Their vulcanization starts slowly, but the vulcanization speed is fast. They are called slow-acting fast accelerators and are mainly used in the production of large rubber products such as tires. In conventional formulations, its dosage is only two-thirds of the accelerator M and DM (the usual amount of accelerator M and DM is 1 to 2 parts). In the so-called "semi-effective vulcanization" system (that is, low sulfur/high accelerator combination), the dosage is 3 to 5 parts (used with 0.2 to 0.4 parts of sulfur), which can obtain good processing safety and improve the vulcanized rubber Comprehensive performance.
③ Thiurams are fast accelerators, mainly used as auxiliary accelerators for thiazoles or sulfenamides.
④The dithiocarbamates are super-fast accelerators, suitable for rapid vulcanization at room temperature, and also used as auxiliary accelerators.
In addition, there are substances that can improve the activity of organic accelerators, called vulcanization activators, that is, accelerators. The most widely used is zinc oxide, with an amount of 3 to 5 parts. The substance that prevents or delays the early vulcanization ("scorch") of the rubber compound during processing and parking before vulcanization is called a vulcanization retarder, that is, a scorch inhibitor. Scorch inhibitors with better effects include N-nitrosoaniline (anti-scorch agent NDPA), N-cyclohexyl sulfurized phthalimide (anti-scorch agent PVJ or CTP), etc. The amount of the former is 0.3 to 1 part, and the latter is 0.1 ~0.5 copies. The research work of anti-scorching agents is still very active.
1. Rubber vulcanization aids, including vulcanizing agents (crosslinking agents), accelerators, activators and anti-scorching agents.
2. Rubber protective additives include antioxidants, antiozonants, anti-flex cracking agents, light stabilizers, ultraviolet light absorbers, harmful metal inhibitors, physical antioxidants, anti-termite agents, anti-rat bite agents, Biting agent, antifungal agent, etc.
3. Rubber reinforcing additives, including carbon black, white carbon black, metal oxides, inorganic salts, resins, etc.
4. Rubber adhesion additives, including m-methyl white system and cobalt salt system adhesives and adhesives
5. Process operation aids include peptizers, solubilizers, plasticizers, softeners, homogenizers, lubricants, dispersants, tackifiers, release agents, mold release agents, etc.
6. Special additives include colorants, foaming agents, defoamers, thickeners, creaming agents, wetting agents, emulsifiers, stabilizers, coagulants, heat-sensitive agents, anti-webbing agents, preservatives, preservatives , Flame retardants, antistatic agents, fragrances and anti-biting agents, etc.