The vulcanization process refers to the semi-finished products made of a rubber material (mixed rubber) with a certain plasticity and viscosity after molding process (such as calendering, extrusion, molding, etc.) through a chemical factor (such as vulcanization) under certain external conditions. The function of the system is to be converted into a soft elastic rubber product or a hard tough rubber product so as to obtain the process performance. In the vulcanization process, the external conditions cause chemical reactions between the rubber compound and the vulcanizing agent in the rubber compound, and the linear rubber macromolecule cross-links to form the macromolecular network structure, thereby greatly improving the rubber Performance, so that the rubber roller to meet the needs of the product to use the hardness, heat resistance, anti-aging, acid and alkali resistance, high temperature, elastic and other physical and mechanical properties and other properties. 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 methods of large and medium-sized rubber roll manufacturers still use vulcanizing cans. The heat sources for vulcanization include steam, hot air and hot water. The main stream is still steam. For hollow core rubber rollers, since the metal core cannot contact water vapor, indirect steam vulcanization is recommended. The time needs to be extended by 1 to 2 times. For special rubber rollers that cannot be vulcanized with a vulcanizing tank, hot water vulcanization is sometimes used.
In order to prevent the difference in heat conduction between the metal core and the rubber, the vulcanization is generally performed in a manner of slowly increasing the temperature and increasing the pressure, and the vulcanization time is much longer than that required for the rubber itself, so that the occurrence of a drop between the rubber roller and the rubber core due to different shrinkages is avoided. Floor. Large rubber roller to achieve uniform internal and external vulcanization and the thermal conductivity of the metal core and rubber, stay in the vulcanization tank is often up to 24 ~ 48h, about 30 to 50 times the normal rubber curing time.
The small rubber roller has been mostly changed to the vulcanizing press of the vulcanizing machine, which completely changed the traditional vulcanizing method of the rubber roller. In recent years, the injection molding machine has also been used for die casting, vacuum sulfiding, and the mold can be opened and closed automatically, the degree of mechanization and automation is greatly improved, and the curing 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 forming 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 production and development of rubber rollers.
At present, the liquid rubber represented by polyurethane elastomer (PUR) has broad prospects in the production of rubber rollers. It adopts the casting form of polyurethane casting machine, discards the complicated molding operation and bulky vulcanization equipment, and greatly simplifies the production process of rubber rollers. . However, the biggest drawback of the pouring type is that the mold must be used. For a large rubber roll, especially a single product, the development of the mold will lead to a substantial increase in production costs, which restricts the popularization of promotion.
In order to solve this problem, in recent years there has been a new process of polyurethane rubber roller manufacturing without mold. It uses polyoxypropylene ether polyol (TDIOL), polytetrahydrofuran ether polyol (PIMG) and diphenylmethane diisocyanate (MDl) as raw materials, rapidly reacts after mixing and stirring, and quantitatively casts it onto a slowly rotating rubber roller metal core. , step by step to achieve the edge of the cast edge curing, the final formation of rubber roller. This process not only has a short flow, a high degree of mechanization and automation, but also saves bulky molds, can freely produce rubber rollers of various sizes according to requirements, and greatly reduces the cost. Now it has become the main development direction of PUR rubber rollers. .
At present, the vulcanization methods of large and medium-sized rubber roll manufacturers still use vulcanizing cans. The heat sources for vulcanization include steam, hot air and hot water. The main stream is still steam. For hollow core rubber rollers, since the metal core cannot contact water vapor, indirect steam vulcanization is recommended. The time needs to be extended by 1 to 2 times. For special rubber rollers that cannot be vulcanized with a vulcanizing tank, hot water vulcanization is sometimes used.
In order to prevent the difference in heat conduction between the metal core and the rubber, the vulcanization is generally performed in a manner of slowly increasing the temperature and increasing the pressure, and the vulcanization time is much longer than that required for the rubber itself, so that the occurrence of a drop between the rubber roller and the rubber core due to different shrinkages is avoided. Floor. Large rubber roller to achieve uniform internal and external vulcanization and the thermal conductivity of the metal core and rubber, stay in the vulcanization tank is often up to 24 ~ 48h, about 30 to 50 times the normal rubber curing time.
The small rubber roller has been mostly changed to the vulcanizing press of the vulcanizing machine, which completely changed the traditional vulcanizing method of the rubber roller. In recent years, the injection molding machine has also been used for die casting, vacuum sulfiding, and the mold can be opened and closed automatically, the degree of mechanization and automation is greatly improved, and the curing 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 forming 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 production and development of rubber rollers.
At present, the liquid rubber represented by polyurethane elastomer (PUR) has broad prospects in the production of rubber rollers. It adopts the casting form of polyurethane casting machine, discards the complicated molding operation and bulky vulcanization equipment, and greatly simplifies the production process of rubber rollers. . However, the biggest drawback of the pouring type is that the mold must be used. For a large rubber roll, especially a single product, the development of the mold will lead to a substantial increase in production costs, which restricts the popularization of promotion.
In order to solve this problem, in recent years there has been a new process of polyurethane rubber roller manufacturing without mold. It uses polyoxypropylene ether polyol (TDIOL), polytetrahydrofuran ether polyol (PIMG) and diphenylmethane diisocyanate (MDl) as raw materials, rapidly reacts after mixing and stirring, and quantitatively casts it onto a slowly rotating rubber roller metal core. , step by step to achieve the edge of the cast edge curing, the final formation of rubber roller. This process not only has a short flow, a high degree of mechanization and automation, but also saves bulky molds, can freely produce rubber rollers of various sizes according to requirements, and greatly reduces the cost. Now it has become the main development direction of PUR rubber rollers. .