Brief Introduction Of Vulcanization Process In Rubber Roller Production

The rubber roller vulcanization process refers to a rubber roller semi-finished product made of a certain plasticity and viscosity (mixed rubber) after the molding process (such as calendering, extrusion, molding, etc.) passes chemical factors under certain external conditions ( For example, the function of the vulcanization system is reconverted into a soft elastic rubber product or a hard tough rubber product to obtain a process of use performance.

   In the vulcanization process, the external conditions cause the rubber compound in the rubber component to chemically react with the vulcanizing agent, and the linear rubber macromolecules crosslink to form a macromolecular structure, thereby greatly improving the rubber. The performance makes the rubber rubber roller obtain the physical and mechanical properties and other properties that can meet the hardness, heat resistance, aging resistance, acid and alkali resistance, high temperature resistance and elasticity of the product. The essence of vulcanization is cross-linking, that is, the conversion of linear rubber molecules into a spatial network structure.

At present, the vulcanization method of large and medium-sized rubber roller manufacturers still uses vulcanization tank vulcanization. The heat source for vulcanization is steam, hot air and hot water. The main stream is still steam. For the rubber core of the hollow iron core, since the metal core cannot contact the water vapor, indirect steam vulcanization should be adopted, and the time needs to be extended by 1 to 2 times. For special rubber rollers that cannot be vulcanized with a vulcanization tank, hot water vulcanization is sometimes used.

In order to prevent the difference of heat conduction between the metal core and the rubber, the vulcanization time is generally adopted by a slow heating and pressure increasing method. The vulcanization time is much longer than the vulcanization time required by the rubber itself, so as to avoid the occurrence of the separation between the rubber roller and the rubber core due to the difference in shrinkage. Floor. The large rubber roller achieves uniform vulcanization inside and outside and makes the metal core and rubber have similar thermal conductivity. The residence time in the vulcanization tank is often as long as 24 to 48 hours, which is about 30 to 50 times of the normal vulcanization time of the rubber.

The small rubber roller has been mostly changed to the vulcanization of the flat vulcanizing machine, which has completely changed the traditional vulcanization mode of the rubber roller. In recent years, the injection molding machine has been used to mold and vacuum vulcanize, and the mold can be automatically opened and closed. The degree of mechanization and automation is 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 vulcanizer 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, liquid rubber represented by polyurethane elastomer (PUR) has a promising future in rubber roller production. It adopts a polyurethane casting machine casting form, which abandons complicated molding operations and cumbersome vulcanization equipment, which greatly simplifies the production process of rubber rollers. . However, the biggest disadvantage of casting is that the mold must be used. For large rubber rollers, especially for individual products, the development of molds will lead to a significant increase in production costs, which limits the popularity of promotion.

In order to solve this problem, in recent years, there has been a new process of polyurethane rubber roller without mold manufacturing. It uses polyoxypropylene ether polyol (TDIOL), polytetrahydrofuran ether polyol (PIMG) and diphenylmethane diisocyanate (MDl) as raw materials, reacts rapidly after mixing and is quantitatively poured onto the metal core of slowly rotating rubber roller. Step by step to achieve side-casting and solidification, and finally form a rubber roller. This process not only has a short process, high mechanization and high degree of automation, but also eliminates the cumbersome molds. It can produce rubber rollers of various specifications and sizes according to requirements, which greatly reduces the cost. It has become the main development direction of PUR rubber rollers. .