Brief Introduction Of Vulcanization Process In Rubber Roller Production

Rubber roller vulcanization process refers to the semi-finished rubber rollers made of rubber (mixed rubber) with a certain plasticity and viscosity after a molding process (such as calendering, extrusion, molding, etc.) under certain external conditions through chemical factors ( Such as the role of vulcanization system), re-transformed into soft elastic rubber products or hard tough rubber products, so as to obtain the performance of the process.

During the vulcanization process, the external conditions cause the compound rubber in the rubber compound to react chemically with the vulcanizing agent. The linear rubber macromolecules are cross-linked to form a macromolecule with a network structure, which greatly improves the rubber. The performance enables the rubber rubber roller to obtain the physical, mechanical and other properties such as hardness, heat resistance, aging resistance, acid and alkali resistance, high temperature resistance and elasticity that can meet the needs of the product. The essence of vulcanization is cross-linking, that is, the process of converting linear rubber molecules into a spatial network structure.

At present, the vulcanization method of large and medium-sized rubber roller production enterprises still uses vulcanization tank vulcanization. The heat source of vulcanization includes three heating methods: steam, hot air and hot water. The mainstream is still steam. For rubber rollers with hollow cores, since the metal core cannot contact with water vapor, indirect steam vulcanization should be used, and the time needs to be extended by 1 to 2 times. For special rubber rollers that cannot be vulcanized by vulcanization tanks, hot water vulcanization is sometimes adopted.

In order to prevent the difference between the thermal conductivity of the metal core and the rubber, the general vulcanization method is to slowly increase the temperature and increase the pressure. The vulcanization time is much longer than the vulcanization time required by the rubber itself, to avoid the decoupling between the rubber roller and the rubber core due to the different shrinkage. Floor. In order to achieve uniform internal and external vulcanization and the thermal conductivity of the metal core and the rubber are large, the residence time in the vulcanization tank is often as long as 24 to 48 hours, which is about 30 to 50 times the normal rubber vulcanization time.

Most of the small rubber rollers have been changed to flat vulcanizing machines for molding and vulcanization, completely changing the traditional vulcanization method of rubber rollers. In recent years, injection molding machine installation, vacuum vulcanization have also been implemented, and the mold can be automatically opened and closed, the degree of mechanization and automation has been greatly improved, and the vulcanization time is short, the product quality is good, and the production efficiency is high. Especially when the rubber injection molding vulcanizing machine is used, the two processes of molding and vulcanization are combined into one, and the time can be shortened to 2 to 4 minutes, which has become an important direction for the development of rubber roller production.

At present, the liquid rubber represented by polyurethane elastomer (PUR) has a broad prospect in the production of rubber rollers. It adopts the pouring form of polyurethane casting machine, abandoning the complex molding operations and bulky vulcanization equipment, which greatly simplifies the production process of rubber rollers. . However, the biggest disadvantage of the pouring type is that molds must be used. For large rubber rollers, especially single products, the development of molds will lead to a significant increase in production costs and restrict the promotion of popularization.

In order to solve this problem, in recent years, a new process of polyurethane rubber rollers without mold manufacturing has begun to appear. It uses polyoxypropylene ether polyol (TDIOL), polytetrahydrofuran ether polyol (PIMG) and diphenylmethane diisocyanate (MDl) as raw materials. After mixing and stirring, it reacts quickly and is poured quantitatively onto the metal core of the slowly rotating rubber roller , Curing step by step while pouring, and finally forming a rubber roller. This process not only has short process, high degree of mechanization and automation, but also saves the cumbersome mold, and can produce rubber rollers of various specifications and sizes according to requirements, which greatly reduces the cost, and has become the main development direction of PUR rubber rollers.