In recent years, the injection molding of liquid rubber (LSR), the injection molding of liquid silicone rubber, has been widely popularized and popularized. Recently, the method has become a common concern for people in the industry because of its advantages of short time automatic molding and plastic composite molding. The following are the latest trends in the injection molding of liquid silicone rubber and the material suitable for this molding.
Because the crosslinking reaction is in the form of addition curing, it can be formed at a relatively low temperature. Two times vulcanization is not necessary in principle because of the formation of the by-products such as no peroxide decomposition residue in the crosslinking reaction. Therefore, it can be integrated with the resin, and can be molded by coating the base coat material, making the seal part and the skeleton part become a whole two yuan molding.
Silicone rubber has excellent properties (heat, Naisai, weather resistance, electrical insulation, flame retardant etc.). Because of these properties, it is possible to make the whole automatic forming of environmental forming, and the whole molding of metal and organic resin. The material itself is colored transparent, so its application involves many areas (such as computer, mobile phone etc.) button, the bottle, (copiers, printers and the like) roller, pipe joint sealing, auto spare parts, the TV picture tube anode cap, diving equipment etc.
In the injection molding of liquid silica gel, a method called "no rubber edge" and "no flow" molding has been popularized. This is a molding method that does not produce useless solidified products and does not need two processing. That is a molding method without producing materials and channels, even without curing. In order to implement this process, model structure and type surface finish, measurement, precision injection machine discharge must meet the requirements, even in the material must also be difficult to generate waste rubber edge materials into the mold cavity of the rubber in the mold cavity is filled with rubber, because too many factors, or because of thermal expansion silicone rubber, rubber material into the parting surface, after curing becomes waste rubber. If the parting surface is designed narrowly, the waste rubber edge will be hard to generate, but at the same time, the air is not easy to drain away, so it will become the reason why the finished product contains bubbles.
It is the curing characteristic of the forming material with no waste rubber edge. Compared with the material used previously, the curing curve of the material is in a rapid turning state (from the beginning of curing to the short end of the curing time). By choosing the appropriate injection conditions of this type of materials, before the mold cavity is filled with the material, curing has not started, the material flow is very good, but when the material is filled with cavity after curing immediately end, even if there is residual pressure, the material will not flow to the parting surface, preventing the waste rubber edge form.