Tips For Molding A Professional Liquid Silicone Rubber

Liquid silicone rubber, or LSR, is an incredibly versatile material used in various industries. It’s commonly found in medical devices and consumer products like baby bottles and kitchen appliances. But did you know that there are specific techniques for molding LSR professionally? If you want to get the most out of your silicone rubber parts, this article will provide essential tips on doing so with precision and accuracy.

What You Will Need

You will need some basic supplies to mold your Silicone Molding. First, you will need a mold. You can purchase a mold or make your own using various materials, including silicone, latex, or soap. Next, you will need to gather your silicon rubber material. There are many brands and types of liquid silicone rubber on the market, so it is important to research to find the best one for your project.

Once you have your mold and material, you are ready to begin the molding process. The first step is to mix the two materials according to the manufacturer’s instructions. Once mixed, you will need to pour the mixture into your mold and let it sit for the allotted time specified by the manufacturer.

The Process

Liquid silicone rubber (LSR) is a two-part platinum-cured silicone that can be injected into molds to create intricate parts with a high level of detail. LSR is also an excellent material for seals, gaskets, and other products that require a high degree of flexibility and durability.  To inject mold LSR, the two-part liquid must first be mixed in a specific ratio. The mixed material is then injected into a mold at high pressure using an injection molding machine. The material is then cured in the mold at room temperature or elevated temperatures, depending on the specific LSR formulation.

Curing the Rubber

Once you have your rubber mold ready, it’s time to cure the rubber. Curing is a process of vulcanization, simply the cross-linking of polymer chains to make the material stronger and more resistant to heat and chemicals. The most common way to vulcanize rubber is with sulfur, but many other chemicals can also be used.

The first step in curing rubber is mixing the vulcanizing agent with the base polymer. This can be done in several ways, but the most common is simply adding powdered sulfur to the liquid polymer. The amount of sulfur added depends on the rubber used; for example, neoprene requires about 2-3% sulfur by weight. Once the vulcanizing agent is mixed in, the mixture is heated to start the vulcanization reaction.

The actual vulcanization reaction involves three main steps: chain scission, cross-linking, and network formation. These shorter chains can then cross-link with each other via covalent bonds, forming a network structure. This network structure gives cured rubber superior strength and resistance to heat and chemicals. The final step in vulcanization is cooling the mixture back down to room temperature so that the cross-linking reaction can stop.