Nowadays, in order to reduce the production cost, many natural rubber products manufacturers will add a certain proportion of reclaimed rubber in the product formula, mostly with latex reclaimed rubber and tire reclaimed rubber. When natural rubber and reclaimed rubber are used together, in order to ensure uniform mixing of the rubber compound, Basically, the natural rubber is fully plasticized and then mixed with the reclaimed rubber (recyclable rubber is good). So is it natural that the natural rubber needs to be plasticized before it can enter the mixing process?
1. Different varieties of natural rubber take different time to obtain the same plasticity
At present, the natural rubber varieties on the market mainly include tobacco sheet glue and standard glue. The tobacco sheet glue and standard glue can be divided into domestic and imported. The molecular structure and various indexes of different varieties of natural rubber are different, so the mastication The performance is different, theoretically the time to obtain the same plasticity is different, usually the order of mastication time is: imported tobacco sheet glue > process tobacco sheet glue > imported standard glue > domestic standard glue.
2. Natural rubber with low Mooney viscosity can be directly mixed without plasticification.
Mooney viscosity is an important indicator to measure the plasticity of natural rubber. The lower the general Mooney viscosity, the better the natural rubber and plastics, and even the direct mixing. Different types and different grades of natural rubber have different initial Mooney viscosity. Among them, Malaysian standard rubber, oil-filled natural rubber and other natural rubbers have low initial Mooney viscosity and are easy to operate. In the application process, the plasticizing process can be skipped and directly mixed.
3. Commonly used plasticizing methods in natural rubber mastication
The mastication process of natural rubber is carried out in an open mill or an internal mixer. When using the open mill to plasticize the natural rubber, the low temperature thin pass and the segmental mastication method are selected for mastication, and the mastication effect is better; when using the internal mixer for mastication, the mastication temperature should be controlled below 155 ° C; natural When the glue and the reclaimed rubber are used together, the mastication process is mostly carried out in an internal mixer. During the mastication process, attention is paid to the mastication time and the mastication temperature, so as to avoid the problem that the rubber material is over-refined and the physical and mechanical properties are degraded.
4. How to improve the mastication effect of natural rubber
The rubber accelerator M is the most commonly used speeding accelerator in natural rubber. It is easy to disperse and pollution-free in the rubber compound; it can not only promote the vulcanization process, but also increase the plasticity of the rubber compound and have the effect of plasticizer. Therefore, many natural rubber product manufacturers often use the rubber accelerator M as a peptizer to improve the mastication effect of natural rubber.
Mastication is one of the main processes in the production of natural rubber products, but not all natural rubbers need to undergo the process of mastication in the application process. When natural rubber/recycled rubber is used together to produce rubber products, it is necessary to decide whether or not to need mastication according to the basic performance characteristics of natural rubber, and how to set the mastication process parameters? It should be noted that when the natural rubber and the reclaimed rubber are used together, the natural rubber after the mastication is only allowed to stand for 4-8 hours to ensure that the rubber molecular chain is relaxed, the rubber compound is uniform, and then the next process is carried out.