The causes of porosity and bubble formation in rubber product
The vulcanization process of rubber products can have problems for various reasons. Some problems, such as shrinkage, mold flash, flow marks, porosity, and bubbles, etc. There are solutions to any of these problems and the optimization of the vulcanized product. Porosity and bubble formation wants one of the possible problems in producing rubber products, which usually in the rubber compound with a higher hardness, the porosity problem is less. Many factors can cause bubble and porosity. Including low pressure during vulcanization and incomplete vulcanization process, Warming up and air trapped, the presence of air and moisture in the elastomeric mixture.
The low pressures of the press machine during the vulcanization is one of the factors causing porosity and bubble formation, which can be solved by setting pressure of press machines. On the other hand, when the rubber compound is under vulcanization, If the time of vulcanization ends up before the middle product reaches a stable state of vulcanization, When opening the mold, porosity and bubble occurs. In order to solve this problem, the vulcanization properties of the rubber compound including the optimal curing time for the product must be obtained and prevented the formation of porosity and bubbles in it.
The warming up and trapping the air creates bubbles and porosity. The air expands and shows after curing. Removing the porosity problem caused by the air trapping in the mixture is difficult. If in products that combine metal and rubber with adhesive, When applying adhesive is not fully discharged gas, then the rubber does not have a good adhesion to the smooth surface, as a result, the air gets trapped and expanded.
Most of the air is trapped during the process of compounding processing and the bubble is intercepted between the layers. In order to remove it, the rubber sheets should be turned into thin sheets using a roll mill and Using cutting and scratching to the exit to be bubbles. Can be used with a small amount of factic in mixture Facilitated exit of air during the mixing process, or, with other additives, improve the adhesion of the mixture and prevented the formation of porosity and bubbles.
The creation of porosity in the product of vulcanized by the presence of air and moisture in the elastomeric mixture is evident, which largely depends on the type and amount of filler and other components used in the mixture as well as on the technology used in the mixing process. In fact, the main cause of porosity in the cured product is the presence of moisture in the mixture, that with using a moisture absorbing the material in a compound formula such as calcium oxide, porosity problems can be significantly reduced.
Vulcan sanat sepahan Co., in order to improve the quality of products and enjoy economical, Based on knowledge and using these processing aid additives, it has been able to optimize the process conditions and improve the properties of rubber compounds.