Differences Between Extruded and Molded HTV Silicone Rubber

There are two processes for the formation of high-temperature silicone rubber: molding and extrusion. Correspondingly, we also divide the silicone rubber compound into molding silicone rubber  and extrusion silicone rubber. Each molding process has its own advantages and disadvantages. In order to help everyone choose the HTV high-temperature silicone rubber compound that is suitable for their own molding process, the following summary compares the differences between solid-state silicone molding and extrusion molding processes.

1, Forming machine

Molded silicone rubber is molded through a vacuum vulcanization machine, while extruded silicone rubber is extruded through an extruder.

2, Vulcanizing agent

Molded silicone rubber can be formed by adding odorless vulcanizing agent or double 25 vulcanizing agent, cutting the strips, and then placing the strip/sheet silicone raw material on the machine for high-temperature vulcanization; The extrusion of silicone rubber is achieved by adding a bis (2,4) sulfurizer or platinum sulfurizer, and directly throwing the entire piece of silicone rubber base into a rubber bucket for extrusion vulcanization molding. Both molded silicone and extruded silicone rubber can reach food grade. Moulded silicone rubber must add odorless vulcanizing agent to reach food grade, while extruded silicone rubber must add platinum vulcanizing agent to reach food grade.

3, Forming speed

The molding time of molded silicone rubber takes 60s to 180s, while the extrusion molding time of silicone only takes a few seconds.

4, Application

Molded silicone rubber is mainly suitable for producing silicone rubber products with certain size, shape, and length limitations. Molded silicone rubber can be designed into products with certain regular sizes through mold opening. For example, products such as silicone phone cases, silicone sealing rings, baby nipples, etc. that are often used in our daily lives are all produced using molded silicone.

Extruded silicone rubber is mainly suitable for producing silicone products in the form of tubes/strips without length restrictions. Extruded silicone can be pre formed by the extruder head and then vulcanized in an oven to produce silicone products with no length restrictions. For example, products such as silicone water pipes and silicone sealing strips commonly used in our daily lives are all produced using extruded silicone.

5, Storage

Molded silicone rubber base can be stored for about a month after adding vulcanizing agents, while extruded silicone rubber base can only be stored for about 3 days after adding vulcanizing agents. If both are not added with vulcanizing agents, they can be effectively stored for up to a year.