The cause of bubbles appearing when silicone rubber products are formed

In the production of silicone rubber products, if there are air bubbles and air holes will affect the quality and beauty of the products, so to improve the qualified rate of products, silicone rubber factory can start from avoiding air bubbles. 

There are generally the following reasons for bubbles:

1. The raw materials

The gas bubbles caused by raw materials include raw gum, the water content of the compound itself, the luminescent and the gas produced by chemical reaction.The most bubble-prone component of the compound is plasticizer (including softener).Because plasticizer belongs to grease more kind, contain low temperature volatile matter and moisture to be in the majority.Pine tar is more abundant.In order to remove water, silica gel products processing plants often in the mix before the pine tar, coal tar heating evaporation.Even so, volatile and low-molecular substances in the plasticizer can evaporate during mixing or vulcanization heating, resulting in pores or bubbles.

2. Processing technology

In the processing technology of silica gel products, there are more factors causing bubbles in the production process.It can be said that most of the bubbles of silicone products are caused by improper operation of the process.Water and substances that act as an isolating agent are often brought in during mixing and thermal smelting. In addition, gases are often permeated during mixing and thermal smelting, and the amount of permeated gases is exponential with the temperature.The higher the temperature, the greater the gas infiltration.

3. Other factors

The moisture and adsorption gas contained in the reinforcing filler such as carbon black and clay are also one of the reasons for the bubble formation of silicone rubber products.

Fiber materials and steel cords are also important factors that cause air bubbles. Fibers and steel wires contain air and moisture. Many products usually do not produce bubbles. The reason is that the dispersed and dissolved gas and water in the rubber material are pushed and collected in the low pressure direction through the framework material.

Sulfur is also an important reason for bubbles and pores in the production of silicone rubber products. Because the tear strength of the low-sulfur rubber is not high, the gas molecules inside the rubber are easy to diffuse and collect in the rubber.