TPE vs. Silicone: Which is Better?

Thermoplastic Elastomer, or TPE, is made up of styrene, olefins, and polyurethane. TPEs are ideal for medical grade devices and food compliance because of their proven safety, low toxicity, and flexibility. Meanwhile, silicone is a synthetic rubber produced by extracting silicon, passing it through hydrocarbons, and combining it with other compounds. Silicone’s higher melting point makes it an ideal material for producing parts for rail, aircraft, and HVAC systems.

Thermoplastic elastomerTPE vs Silicone
Thermoplastic elastomer (TPE) vs Silicone
[Image source: https://omnexus.specialchem.com/ and https://en.wikipedia.org/wiki/Silicone]

TPE, or thermoplastic elastomer, and silicone are two rubber compounds that have a number of advantages. Both are commonly used in injection molding. Silicone behaves uniquely at high temperatures and lacks a melting point, remaining solid until combustion occurs. Silicone rubber will gradually lose mechanical qualities and become brittle when exposed to high temperatures (200-450C).

There’s a lot to know about the difference between TPE vs Silicone.

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What s Thermoplastic Elastomer (TPE)?

Thermoplastic elastomers (TPEs) are polymers that have properties of both thermoplastics and elastomers. These materials are thermoplastic, which means they can be melted and reformed repeatedly without undergoing chemical deterioration. At the same time, they have elastomeric qualities, which allow them to stretch and return to their former shape after deformation, much like rubber.

Thermoplastic elastomer (TPE) is a polymer mix or mixture that, when heated above its melting point, may be molded into a variety of shapes, similar to a standard thermoplastic material. Within its desired temperature range, it exhibits elastic characteristics without requiring any cross-linking during shaping. Thermoplastic elastomers are processed using a variety of plastic production techniques such as injection molding, extrusion, and blow molding. Overmolding and two-shot molding are two advanced processing techniques that can be used on TPE materials. It may also be subjected to secondary procedures such as welding and bonding with other materials.

Characteristics of Thermoplastic elastomer (TPE)

  • Thermoplastic elastomers (TPEs) have rubber-like flexibility and elasticity, allowing for stretching and returning to their original shape.
  • Injection molding, extrusion, and blow molding are examples of standard plastic manufacturing techniques that can be applied to them. Their ability to harden when cold and soften when heated is the explanation for this.
  • TPEs are recyclable and reprocessable, unlike standard thermoset rubbers, which cannot be remelted once cured.
  • They can be utilized in a wide range of applications due to their high resistance to chemicals, oils, and solvents.
  • TPEs have high abrasion resistance and resilience, which contributes to their extended life in a variety of applications.
  • Unlike many polymers, which break rapidly at low temperatures, they maintain pliability and functionality at these temperatures.
  • Some TPEs are biocompatible, making them suitable for usage in healthcare and medical environments.
  • TPEs are easily colored, providing aesthetic freedom in product design.
  • Many TPEs are suitable for outdoor applications due to their high resistance to UV radiation and weathering.
  • TPEs are often lighter than standard rubbers, which might be useful in applications where weight is an important consideration.
  • he flexibility to use regular plastic processing procedures, as well as TPEs’ recyclability, can result in cost reductions in manufacture.

Application of Thermoplastic elastomer

  • Automotive industry: Thermoplastic elastomers are commonly utilized in automotive sealing systems, such as door, window, and trunk seals. Their elasticity and endurance ensure excellent sealing capabilities, reducing noise and limiting water infiltration.
    TPEs are used for airbag covers, door knobs, dashboards, and other interior components. They are soft to the touch and easily sculpted into complex shapes.
  • Medical device: Medical devices containing TPEs include tubing, catheters, and syringe plungers. Their biocompatibility and sterilizability make them ideal for these important applications.
  • TPEs are used to make grips for tennis rackets, golf clubs, and bicycle handles. They are perfect for these applications because they offer a comfortable grip and are sweat-resistant.
  • TPEs are acceptable to use in toys because they are non-toxic and meet safety regulations. They are used to create a variety of toys, like as flexible figurines and soft play things.
  • TPEs are used in construction as sealants and gaskets. Their elasticity and weather resilience make them ideal for creating long-lasting seals in windows, doors, and other structural elements.
  • Roofing membranes provide strong, weather-resistant solutions that can withstand high temperatures and UV radiation. They are also used in roof membranes.

What is Silicone?

Silicone is an inert synthetic chemical that comes in several forms (oil, rubber, and resin). Sealants, adhesives, lubricants, medical uses, cookware, and insulation all contain heat-resistant and rubber-like compounds. Silicone is a polymer composed of silicon, carbon, hydrogen, oxygen, and, in certain situations, additional elements.

Silicone refers to a wide range of fluids, resins, and elastomers based on polymerized siloxanes, which are compounds with chains of alternating silicon and oxygen atoms. Their chemical inertness, resistance to water and oxidation, and stability at high and low temperatures have resulted in a wide range of commercial applications, including lubricating greases, electrical wire insulation, and biological implants (such as breast implants).

Characteristics of Silicone

  • Silicones are non-chemically reactive and have a low thermal conductivity: It takes a lot of energy to break the connections between the silicon-oxygen chains that make up the polymeric skeleton of silicone molecules. Because most molecules that come into contact with silicones lack the energy to overcome the silicone molecule’s resistance to change, chemical reactions are slowed. As a result, silicone is often thought to be chemically inert. These stable silicone bonds are responsible for many of silicone’s desirable features.
  • Thermal conductivity is typically poor for silicones: This is due to silicone’s molecular structure, which impedes the passage of heat vibrations from one molecule to the next. This can be useful for some silicone applications, such as oven mitts. However, in other cases, the inability to adequately transport heat is an issue. In that instance, thermally conductive fillers can be added to the silicone formulation to facilitate heat transfer for the desired use.
  • Toxicity is also low: Silicone is generally regarded as a very safe material for human health. Food-grade and medical-grade silicone compounds have been FDA-approved for usage in contact with the food we eat every day, as well as long-term implantation in the human body. To ensure the highest levels of safety, silicone products should be used in accordance with the manufacturer’s instructions, just as with any other chemical.
  • Silicone is very resistant to oxygen, ozone, and ultraviolet light: Silicone-oxygen bonds are more stable than those formed between carbon atoms in organic polymer chains. UV radiation can supply more energy than is required to break down C-C bonds, but it is insufficient to destroy Si-O bonds. This is why silicones resist UV radiation and oxidation better than carbon-based polymers. Silicones can be utilized on components that are exposed to harsh outside conditions.
  • Silicone has excellent gas permeability and thermal stability: Silicone’s chemical chains have holes large enough to let gas molecules flow through but not water molecules. The combination of water repellency and gas permeability results in coatings that provide the luxury of water-resistant, breathable materials.
  • Silicone has a higher resistance to organic compound solvents: Silicone’s nonreactive composition and low surface energy make it immune to most chemical attacks. However, a few inorganic compounds, particularly sulfuric and hydrofluoric acids at high concentrations, can harm silicones. Toluene, mineral spirits, gasoline, and carbon tetrachloride are examples of organic chemicals that can serve as solvents and cause silicone breakdown only after continuous exposure.

Applications of Silicone

  • Used in Cosmetics: Silicones assist cosmetics, shampoos, and conditioners retain shine. They aid in cosmetic application by acting as a solvent and carrier for the products. Furthermore, silicone has a translucent, glossy feel, high biocompatibility, and evaporates quickly from the skin.
  • Photovoltaic and Solar Panel Materials: Silicone is a conductive glue used in photovoltaic and solar panels. The material is also utilized as an encapsulant for solar panels, where its environmental stability and transparency contribute to higher efficiency. Silicone’s superior mechanical and chemical qualities lower total repair costs and extend product life.
  • Electrical transmission applications: Another application for silicone is in electronics. It is utilized as a sealant, glue, or coating on a variety of circuit components, including connections, capacitors, and transistors. Silicone materials are good for electronics because they keep circuit components safe from heat, shock, and debris. Its use promotes improved energy efficiency and connectivity.
  • Manufacture adhesives and sealants: Silicone is perhaps best known for its usage in adhesives and sealants. Silicone, whose main constituent is silica, becomes an adhesive after a series of heating and chemical mixing procedures. Silicone is a great adhesive due to its chemical and weathering resistance, as well as its superior thermal properties
  • Used in the construction and renovation of commercial and residential buildings: Silicones are frequently employed in construction as coatings, adhesives, or sealants to improve building insulation and energy efficiency. Silicones are perfect for this application because of their durability, weather resistance, flexibility, ability to connect a wide range of materials, and superior thermal insulation properties.
  • Used in bakeware and cookware: Silicone items are widely used in bakeware and cookware. Baking molds, kitchenware, and oven mitts are all examples of its use. This is because silicone is flexible, antibacterial, heat-resistant, and simple to clean.
  • To Maintain External Coatings: Silicone-enhanced paints offer flexibility to external coatings on painted surfaces, allowing them to resist freezing and thawing cycles without cracking. They’re also utilized on road surfaces and maritime boats to lessen the environmental impact of oils, gasoline, salt, and acid rain.

Thermoplastic Elastomer TPE Vs Silicone

Thermoplastic Elastomer (TPE)Silicone
TPE is a class of copolymers or a physical mix of polymers, typically a mix of plastic and rubber.Silicone is a synthetic rubber made from silicon processed through hydrocarbons and mixed with other chemicals.
TPE is made of styrene, olefins, and polyurethanes.Silicone is generally considered a rubber, though it has both plastic and rubber properties.
TPE is versatile, chemically resistant, cost-effective, with good thermal properties and material stability.Silicone has excellent thermal conductivity, fire resistance, chemical stability, and resistance to heat and cold.
TPE has a melting point of 260-320 degrees C and a temperature resistance range of 130 to 150 degrees C.Silicone does not have a melting point; it remains solid until combustion and has a temperature resistance range of 200 to 300 degrees C.
TPE pellets are heated in a barrel, turned into liquid resin, and injected into a mold under high pressure.Silicone molding begins with a high-temperature mold created using CNC machining, then injected into the mold.
TPE can be manufactured using injection molding, extrusion, blow molding, or thermoforming. It does not need curing agents or high temperatures to establish its shape. This reduces the complexity and cost of processing TPE.Silicone can be processed using injection molding, extrusion, compression molding, or liquid injection molding. It takes curing agents and high heat to produce its shape. This increases the complexity and cost of processing silicone.  
TPE can be reprocessed and altered after heating.Silicone cannot be reprocessed or altered after heating.
TPE can tolerate temperatures from -30°F to 250°F.Silicone can tolerate a broader temperature range from -60°F to 480°F.
TPE has a soft touch and is highly flexible, ideal for soft-touch grips and sealing rings.Silicone is less flexible than TPE but highly durable, suitable for gaskets, tubing, and custom parts.
TPE is less likely to return to its original thickness after being compressed.Silicone has a better compression set and is more likely to return to its original thickness after compression.
TPE is more cost-effective due to its simpler manufacturing process.Silicone is more expensive to manufacture because of its complex process.
TPE is more sustainable as it can be easily recycled by melting and reforming.Silicone cannot be recycled once set into a solid mold, adding cost and environmental impact.
TPE is generally safe to use, though concerns exist about phthalates, which are present in low, legal amounts.Silicone is safe and stable, widely used in medical and food applications, with no significant toxicity concerns.
Choose TPE based on replacement needs, performance improvements, cost targets, and environmental conditions.Choose silicone based on the required chemical, mechanical, and physical properties for the intended purpose.

References

  • https://www.xometry.com/resources/materials/tpe-vs-silicone/
  • https://www.timcorubber.com/blog/archive/tpe-vs-silicone-which-is-better/
  • https://europlas.com.vn/en-US/blog-1/silicone-vs-tpe-what-are-the-differences
  • https://www.kaysun.com/blog/thermoplastic-elastomer-vs-liquid-silicone-rubber
  • https://www.avient.com/idea/whats-difference-tpes-vs-silicones
  • https://hmroyal.com/blog/tpe-vs-silicone/
  • https://www.simtec-silicone.com/blogs/thermoplastic-elastomers-tpe-vs-liquid-silicone-rubber-lsr/

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Kabita Sharma

Kabita Sharma, a Central Department of Chemistry graduate, is a young enthusiast interested in exploring nature's intricate chemistry. Her focus areas include organic chemistry, drug design, chemical biology, computational chemistry, and natural products. Her goal is to improve the comprehension of chemistry among a diverse audience through writing.

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