Predictability of dosage and processing temperature of scorch retarder CTP

Predictability of CTP dosage and processing temperature

As long as the scorch retarder CTP is used, different processing temperatures can be designed according to the needs of the rubber product. This is called the predictability of CTP dosage and processing temperature. When used in combination with three different sulfenamide accelerators (NOBS, NS, CZ), the amount is linear with the Mooney coke. Therefore, using this linear function relationship, if you want to improve from the established processing safety to another security, you only need to determine the exact amount of CTP required for the application. In addition, the optimum processing temperature and safety can be foreseen. Figure 4-5 shows the effect of processing temperature and CTP in the formulation. Because CTP is not like other scorch inhibitors, it does not decompose during normal processing and vulcanization temperature. By using the invariance of molecular structure and its linear relationship in its anti-coke effect, it can be used to process temperature and Prediction of security compliance. The solid line in Figure 4-5 represents that CTP is not added to the styrene-butadiene rubber, and the dotted line represents 0.25 parts of CTP. From the solid line A (the abscissa 135 ° C, the ordinate 10 mim), its processing safety value (T2) is about 20 mim. Therefore, the safety of CTP in the formulation is doubled at the same temperature. Similarly, if you want to maintain a certain processing safety value (T2 = 10mim) to increase production, you can draw a parallel line from the A point and the dotted line to point C, which is equivalent to 145 ° C, that is, the processing temperature can be from 135 The same safety is achieved when °C is raised to 145 °C, but the yield can be increased.

In general, the safety of rubber processing is linear with the amount of CTP. The slope of the line depends on the ingredients in the formulation, such as the type of elastomer, accelerator, vulcanizing agent, type and amount of filler. CTP can be applied to all available sulfur vulcanized rubbers and almost all accelerators. However, it is ineffective for vulcanization systems with peroxides, resins or metal oxides and is generally not used in latex formulations. CTP has the best effect on the sulfenamide/sulfur vulcanization system scorch retarder. The order of effect is as follows: natural rubber > nitrile rubber > ethylene propylene rubber > butyl rubber > neoprene. The scorch retarder CTP is less effective in a vulcanization system containing a thiuram or thiocarbamic acid accelerator. The anti-coke effect of CTP is closely related to the use of sulfur, and is usually optimal when it is used in an amount of 1.5 to 3.0 parts. The dosage of CTP is usually in the range of 0.1-0.45 parts, and has no effect on the modulus, elasticity, creep, permanent deformation, heat storage, abrasion, oil swell resistance of the vulcanized rubber, and no adhesion to rubber or chemical fiber fabric or steel wire. Bad effects. If the amount exceeds 0.45 parts, it is necessary to pay attention to the modulus after vulcanization, which may be slightly decreased, and also has a certain influence on compression deformation, heat generation, elasticity and creep. The remedy after this problem is to increase the amount of sulfur (increased by 40% of CTP) or increase the amount of accelerator (increased by 20% of CTP), which can adjust the modulus. This product makes the color products slightly discolored, not suitable for color or light color products. It is low in toxicity and avoids products used in contact with food.