When deciding whether to employ thermoset elastomers (rubber) or LSR in a product design, producers look for ways to distinguish rubber from plastic in the context of precision, molded parts. Despite the fact that their chemical compositions and molding qualities are dramatically different, product designers make the error of thinking thermoset elastomers and plastic are interchangeable.

New product designers must overcome all potential stumbling hurdles during the creation process because there are fewer parts and more sophisticated combinations (as in any pet toy, culinary gadget, or other consumer item).

WHAT’S THE DIFFERENCE BETWEEN LIQUID SILICONE RUBBER (LSR) AND THERMOPLASTIC ELASTOMERS? (TPE)

The chemical properties of thermoplastic elastomers (TPE) and liquid silicone rubber (LSR) are identical. Both materials are good for a wide range of injection molding applications, but there are some key differences to keep in mind when determining which material to utilize for specific end products. TPE and LSR are good substitutes for synthetic and natural rubber, however they are not interchangeable.

LSR is a thermoset substance, whereas TPE is a thermoplastic. Each material has its unique properties, reacts to heat differently, and behaves differently during the molding process. LSR, for instance, hardens whereas TPE dissolves.

At room temperature, TPE and LSR have comparable physical properties, but there are distinct advantages and disadvantages to choosing TPE over LSR and knowing which is best for your application is critical.

Thermoplastic elastomers have a lot of advantages over silicone in pet toys, culinary gadgets, and other consumer goods (LSR). They utilize less energy during production, for example. When heated, thermoplastic elastomers are a polymer mixture that melts and forms into plastic.

TPE has similar elasticity to LSR, however the elastomeric behaviour changes due to cross-linking capabilities, where the polymer chains are chemically bonded together in places by covalent bonds (which LSR has).

By deleting the cross-link, you can achieve faster cycle times and lower costs. TPE material has excellent chemical resistance, but only at low and high temperatures. TPE can also be made non-sticky, which repels dirt and other contaminants.

  • Resistance to abrasion
  • Extremely adaptable
  • Excellent fatigue resistance
  • Outstanding impact resistance
  • There is a low population density.
  • Resistance to chemicals and the environment
  • At room temperature, it’s tough and flexible.
  • Injection moulding on a big scale is possible with this material.
  • Low and high temperature resistance (-30–140 degrees Celsius)

TPE may be remolded in a variety of ways because it does not change chemically. The only disadvantages of TPE are how it melts at high temperatures (which may be beneficial in some cases) and how it deforms under continuous pressure.

LSR can withstand a wide variety of temperatures (up to 400 degrees Celsius) and yet stay stable. LSR offers excellent chemical resistance to a wide range of solvents, oils, and other chemicals, making it perfect for automobile gaskets and O-rings.

Comparison of LSR and TPE

LSR’s sterilizing resistance and miniaturization properties have aided its quick adoption in medical and healthcare applications. As a result, LSR is appropriate for use in products that come into contact with people.

LSR is available in a range of hardnesses, ranging from 3 to 80 Shore A, with 50 Shore A being the most prevalent and having the maximum tensile and tear strength. The best sealing property is LSR hardness 30 Shore A. Low durometer silicone elastomer gels can reach less than 10 Shore A.

TPE materials can be reused several times if they are kept in good shape. On the other hand, integrity and performance have no negative consequences. TPE may be reprocessed and remoulded numerous times without losing its compression set property by reheating, softening, and hardening it.

As a Molding Process, LSR vs. TPE

The key difference between the two is that LSR undergoes a chemical connecting process. Injection barrels are filled with liquid A/B material composites, which are then heated in the mound. TPE pellets are melted and cooled in the injection barrel before being injected into the mound.

Throughout the molding process, both LSR and TPE materials are used in overholding and 2-shot molding. Because of its low melting point, TPE can link to a larger spectrum of plastic materials. Due to its high processing temperatures, LSR can only bind with high-performance engineering thermoplastics like polyimides, polycarbonates, and glass reinforced PBTS.

We cast both LSR and TPE materials in the same mold for improved bonding and integration in LSR 2-shot molding; both materials should melt at similar temperatures.