Liquid silicone rubber(LSR) and thermoplastic elastomers(TPE) are advantageous substitutes for synthetic or natural rubber because they have many of the same characteristics. For many different uses, both sorts of materials are perfect.

However, there are notable distinctions between thermoplastic (thermoplastic elastomer) and thermoset properties (silicone elastomer).

What is Liquid Silicone Rubber?

Liquid silicone rubber (LSR) is a synthetic material made of polymers that are connected and structured by chemical bonds and that, when exposed to heat, permanently harden.

In the synthetic resin known as liquid silicone rubber, polymers are joined by a chemical bond. After the mixture is heated, polymer cross-linking creates a chemical connection that gives the product lasting strength and structure.

Advantages And Disadvantages of LSR

The benefits of LSR include:

  • superior to thermoplastics in high temperature resistance
  • Flexible design options, such as thick-to-thin wall structures
  • high tear resistance
  • Biocompatibility
  • increased chemical resistance
  • superior set of compression

LSR drawbacks include

  • No capacity to recycle
  • not being able to be reshaped after curing
  • scorching potential if heated after curing
  • Protracted curing time, which increases production time and cost
  • Early cure might result in production delays since the machinery needs to be removed and cleaned.
  • Handling liquid plastic may be challenging.
  • a thick or bulky look

Uses of Liquid Silicone Rubber

  • surgical implants
  • Hardware and gaskets in household gadgets like microwaves
  • Keyboards or touchpads on devices with electronic interfaces
  • O-rings
  • Electronic sealed housing,
  • Pump housing,
  • Hearing aid parts,
  • Baby nipples and pacifiers.

What Are Thermoplastic Elastomers?

Thermoplastic elastomer (TPE) is a synthetic plastic that, without altering its chemistry, melts when heated and hardens when cooled.

A thermoplastic is a type of plastic polymer that typically contains fossil fuels. There are now bio-based TPE products available that come from sources including corn, sugar cane, beets, soy beans, cellulose, vegetable oils, plants, or algae.

When temperatures approach its melting point, producers shape and create TPE. Its elasticity is comparable to that of cross-linked materials like LSR, but its elastomeric nature is not a result of the cross-linking.

For more information see our guide on the Thermoplastic Elastomer: The Ultimate Guide

Advantages And Disadvantages of TPE

  • Abrasion resistance
  • Excellent colorability
  • Good electrical properties
  • Heat-sealable
  • High elasticity
  • High fatigue resistance
  • High impact strength

Uses of Thermoplastic Elastomer

  • Seals, impact-resistant technology, soft-touch grips, and component housings
  • O-ring seals
  • Some food-contact-approved products include infant bottles, toddler cup spouts, and bottle cap and closure liners (presuming FDA regulatory compliance)
  • Baby bottles
  • Bottle caps
  • Seals

Thermoplastic Elastomer vs Liquid Silicone Rubber: What is the difference?

The main difference between the two is how they react to heat. After TPE is heated, reprocessing is possible. LSR cannot be altered once heat is applied.

Product Performance

LSR offers superior quality at a higher cost as compared to TPE. LSR also performs better than any other rubber on the market.

Moldability Process

The characteristics and heating behavior of TPE and LSR affect moldability:

TPE: Plastic pellets are heated to a liquified state before being pressure-molded into parts that, when cured, retain their strength and shape. Plastics may be used again and molding can be reversed (reground/melted) to fix flaws.
LSR: After heating viscous plastic to generate polymer cross-linking, the ensuing chemical bond gives the material irreversible strength and form. Mixing a catalyst with another component before injecting it into the mold is another typical method for starting cross-linking in LSR.

Is LSR a thermoplastic?

Because LSR is a thermosetting polymer, unlike its thermoplastic equivalent in TPE, it cannot be recycled once it has been formed. Sand or silicon dioxide is the primary raw ingredient, which is mixed with methyl chloride to produce several varieties of silicone, including liquid silicone rubber.

Is TPR better than silicone?

In high temperatures, silicone has an advantage over TPE. TPE can withstand temperatures of 130°C to 150°C theoretically, while silicone can withstand temperatures of 200°C to 300°C. Above that range, TPE will deteriorate and break.

Is silicone rubber thermoplastic or thermoset?

A common thermoset material is liquid silicone rubber (LSR), which is used in the component on the right.

Is LSR an elastomer?

A two-part platinum-cured elastomer that can be injected into a mold cavity to create a component is called liquid silicone rubber. In the elastomer sector, LSR is particularly adaptable and is used in a wide range of components, from consumer goods to medical equipment and everything in between.

What is the difference between TPE and rubber?

Rubber materials often have greater tensile strength, elongation, and notably compression set when all other factors are equal. TPEs have advantages for the environment since they may be widely utilized as "filler" or regrind in a variety of applications because their heat bonding are reversible.

Is thermoplastic elastomer safe?

Yes, they are secure enough to manufacture medical tubing and baby cups. TPEs can also be designed for fire retardant performance if that is required for the application. Both rashes and allergies are not brought on by the substance.

Is silicone compatible with TPE?

Thermoplastic Elastomers (TPE) Although "thermoset" and "thermoplastic" seem similar, they are not the same. TPE materials are thermoplastics, whereas LSRs are thermosets.

What are 5 thermoplastic elastomers?

Styrenic block copolymers (TPE-S), polyolefin blends (TPE-O), elastomeric alloys, thermoplastic polyurethanes (TPE-U), thermoplastic copolyesters (TPE-E), and thermoplastic polyamides are the six primary TPE groups that are commercially available (TPE-A).


About Frank

With a background as an injection molding engineer at Kaysun, Frank brings unique depth and insight to his role as Business Development Engineer. His ability to synthesize information and pair need with opportunity is a benefit to prospects and customers alike.

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