Technological elements of rubber production
Source: internal company
There are many kinds of rubber products, but the production process is basically the same. The basic process of rubber products with general solid rubber —— raw rubber as raw material includes: plasticizing, compounding, calendering, pressing, forming, and vulcanization six basic processes.
The rubber processing process is mainly to solve the contradiction between the plastic and elastic properties of the process. Through a variety of technological means, make the elastic rubber into plastic, and then add a variety of coordination agents made of semi-finished products, and then through vulcanization make the semi-finished products with plastic and high elasticity, good physical and mechanical properties of rubber products.
This article focuses on rubber plasticizing and mixing these two processes.
1. Plasticizing of rubber
Raw rubber is elastic and lacks the necessary plasticity for processing, so it is not easy to process. In order to improve its plasticity, the raw rubber is plasticised so that the compounding agent is easily and evenly dispersed in the raw rubber during mixing, and also helps to improve the permeability of the rubber into the fibres and the mobility of the rubber during calendering and moulding.
The process of degrading the long chain molecules of the raw rubber to form plasticity is called plasticizing. There are two methods of plasticising raw rubber: mechanical plasticising and thermal plasticising.
- Mechanical refining is the degradation of long-chain rubber molecules by mechanical squeezing and friction at a moderately high temperature, resulting in a change from a highly elastic to a plastic state.
- Thermoplastic refining is the degradation and shortening of long chain molecules through the introduction of hot compressed air into the raw rubber under the action of heat and oxygen to achieve plasticity.
2. Compounding of rubber
In order to adapt to different conditions of use and to obtain different properties, as well as to improve the performance of rubber products and reduce costs, different compounding agents must be added to the raw rubber. Mixing is a process in which the raw rubber is mixed with the compounding agent and placed in the rubber-making machine to make the compounding agent completely and uniformly dispersed in the raw rubber.
The quality of the mixing is a decisive influence on the further processing of the rubber and the quality of the finished product, even if the formula is very good rubber, if the mixing is not good, there will be uneven dispersal of the compounding agent, the plastic material is too high or too low, easy to scorch, spray frost, etc., so that the calendering, pressing out, glue coating and vulcanization processes can not be carried out normally, but also lead to a decline in product performance.
The rubber material obtained after mixing is called mixed rubber. It is a semi-finished material for the manufacture of various rubber products, which are usually sold as a commodity. Buyers can use the rubber material to directly process, shape and vulcanize into the required rubber products.