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M.R. Mold

Liquid Silicone Rubber (LSR) Injection Molds

What Is Liquid Silicone Rubber?

4-cavity duckbill with in-mold slitting4-cavity duckbill with in-mold slitting

Liquid Silicone Rubber is a crosslinked (rubber) silicon-based elastomer, reinforced with unique filler systems, that provides outstanding properties. It offers a unique combination of chemical and mechanical properties thermoplastic elastomers (TPRs and TPEs) cannot match.

Silicone can last for years at temperatures that would melt most plastics (+250°C), and it retains flexibility at temperatures as low as -65°C.

Because of this, silicone provides the following benefits:

  • Long service life
  • Good electrical insulating quality
  • Excellent sealing properties

It's also low in toxicity, has no detectable odor, and can be molded in transparent form.

LSR's crosslinking ability stabilizes it in most any environment, and it holds shape even under load, providing low compression and tensile sets. It does not shrink once molded, as there is nothing that leaches or extracts out of the material. LSR is accepted by the FDA as a long-term implantable in the human body due to its biocompatible nature. In addition, the wide range of hardness and colors have made silicone elastomers the material of choice for an ever-increasing number of applications.

We're the LSR Mold Pioneers

Pacifier moldPacifier moldM.R. Mold is proud to be a pioneer in manufacturing LSR molds since 1985.  A prominent factor in our success has been a commitment to continual improvement in all phases of mold manufacturing.

With LSR presenting many challenges in the molding process, a high degree of precision is expected and required for every mold we build. Our molds deliver a high level of efficiency and productivity, while providing excellent value throughout the life of the tool. And we're one of the few companies in the United States offering waste-free LSR molds utilizing our own proprietary cold runner system.

Our highly skilled staff excels in translating complex 3D part geometry into state-of-the-art injection molds. Our customers are comfortable knowing they're working with a high level mold builder whose expertise goes far beyond simple flat parting line tools. Although we specialize in liquid silicone molds for medical applications, M.R. Mold serves many other industries, including dental, aerospace, automotive, and consumer products.

Respiratory products for premature infantsRespiratory products for premature infants

Infant care productsInfant care products