HTV silicone rubber belongs to a kind of silicone rubber raw materials, widely used in aviation, aerospace, electronic and electrical, light industry, machinery, construction, chemical industry, medicine, daily necessities, etc. The following shares three molding processes of HTV silicone rubber.
At present, HTV silicone rubber on the market is divided into HCR silicone rubber and liquid silicone rubber according to the physical state. The solid silicone molding process is mostly compression molding and extrusion molding, liquid silicone is mostly injection molding.
1. Compression Molding
Compression molding is also called hot press molding, first hcr silicone rubber raw material is mixed well, and then put in the high-temperature mold to add (double 25 or double 24) silicone vulcanizing agent, through the flat vulcanizing machine to apply pressure, high-temperature vulcanization molding.
The hardness of silicone raw materials for compression molding is usually 30-70 shore A. In the process of producing compounding rubber, the silicone manufacturer first puts the methyl vinyl silicone rubber into a two-roller refiner or a closed kneader, and then gradually adds white carbon black, silicone oil, etc. and other additives to refine it repeatedly. According to the different fillers and additives added, the performance of the produced silicone also varies.
This molding process is relatively low cost, high yield, and more commonly used. It is mostly used in the production of single-color silicone products, and can also be applied to multi-color and multi-hardness products, but the structure of the products is inflexible and restricted. In addition, it can also be applied to wrap plastic and wrap metal, again inflexible in structure, and there are temperature requirements for the wrapped objects, generally requiring the wrapped objects to be resistant to 356℉ without deformation.
The shape of this craft mold determines the shape of the produced silicone products, which are mainly used in silicone industrial accessories, silicone buttons, silicone gifts, silicone bracelets, silicone watches, silicone cell phone covers, silicone kitchenware, silicone mats, ice grids, cake molds, etc.
2. Extrusion Molding
Extrusion molding is a continuous molding process like toothpaste extrusion. It is suitable for the production and processing of HCR silicone with dichlorobenzoyl peroxide or liquid silicone with a platinum vulcanizing agent. The silicone rubber material is continuously extruded into various semi-finished products of different shapes under the interaction of the extruder barrel and the rotating screw and transported out of the machine. The products formed by this process are generally strip-shaped products, which are mostly used for the production of silicone products such as silicone tubes, silicone wire and cable insulation sleeves.
3. Injection Molding
The injection molding process uses an injection machine, and the raw material used is the addition liquid silicone. Its principle is to feed the part A and part B of the two-component silicone rubber into the screw cavity of the injection machine in a ratio of 1:1, and then mix and stir the silicone uniformly through a mixer, at a high temperature (266°F) for 100-150 seconds The cured elastomer was obtained after a period of time. This molding process is widely used in the fields of medical care, silicone pacifiers, baby products, diving products and other silicone products.