TPE, or thermoplastic elastomer, and silicone are two similar rubber materials that both offer several advantages. Both are commonly used in the injection molding process. Silicones exhibit unique behavior at high temperatures and have no melting point, remaining solid until combustion occurs. At high temperatures (200-450C), silicone rubber will slowly lose its mechanical properties over time and become brittle. The melting point of TPE is 260-320C.
This article is about TPE VS. Silicone and explains the difference between TPE and silicone. We will learn what TPE and silicone are, how to choose the right material, safety precautions, and how silicone and TPE should be used.
1. What is thermoplastic elastomer (TPE)?
Thermoplastic elastomers or TPEs are sometimes called thermoplastic rubbers. TPE is a class of copolymers or physical blends of polymers consisting of materials with thermoplastic and elastomeric properties. While most elastomers are thermoset, thermoplastics are relatively easy to work with in manufacturing. Thermoplastic elastomers have the typical advantages of rubber and plastic materials.
An advantage of using thermoplastic elastomers is the ability to stretch to a moderate elongation and return to their original shape, creating a longer life and better physical range than other materials.
2. What is silicone?
Silicones, also known as polysiloxanes, are known for their flexibility and temperature resistance. Silicone is also flame retardant, breathable, hypoallergenic, chemically inert, and nonstick. As an elastomer, silicone rubber has an inorganic silicon-oxygen backbone linked to organic molecules.
Steam, hydrocarbon fuels, alkalis, acids, trichloroethylene, and aromatics are not resistant to silicone. Electronics, industrial, aerospace, construction, automotive, medical, consumer, and HVAC applications commonly use this material.
3. What are thermoplastic elastomers made of?
Thermoplastic elastomeric materials belong to a class of copolymers or physical mixtures of polymers, usually, plastics and rubbers, made from materials that have both thermoplastic and elastomeric properties. Thus, thermoplastic elastomers are a mixture of plastic and rubber.
4. What material is silicone made of?
Is it silicone rubber or plastic? Scientifically speaking, silicone is in a gray area but is generally considered rubber. It is a man-made elastomer that combines the properties of plastic and rubber. As elastomers are often referred to as rubber, silicones can be used to form liquids, solids, and rubber-like products. Silicone is also easily confused with silicon, although they are different materials. The element silicon is a polymer (a large molecule with repeating units).
5. How about the product performance of TPE and silicone?
TPE and silica gel are high-quality products, so the pillows made from them are also high-quality products. Silicone products exhibit excellent properties, such as thermal conductivity, fire resistance, good chemical stability, flame retardancy, excellent heat and cold resistance, etc. performance, and material stability.
6. What is the melting point of thermoplastic elastomers (TPE)?
The melting point of thermoplastic elastomer is 260-320°C, and the temperature resistance range of TPE is theoretically 130-150°C. If it exceeds this range, TPE will age and crack.
7. What is the melting point of silica gel?
Silicone has no melting point. It remains solid until combustion occurs. Over time, silicone rubber will lose its mechanical properties and become brittle at high temperatures (200-450 degrees Celsius) The temperature range of silicone is considered to be 200 to 300 degrees Celsius.
8. What is the process flow of TPE and silicone injection molding?
The process of silicone injection molding begins with a molding tool created using CNC machining. The tool must be a high-temperature tool capable of withstanding the silicone molding process. The tool can then be polished to allow for different polishing options.
Next, the finished tool is loaded into a special silicone injection molding machine that is finely tuned to precisely control shot volume. Materials used include standard silicones and specific grades for different part applications. Once the parts are ready, they are removed from the mold and used as prototype or production parts.
During the TPE injection molding process, TPE pellets are fed into the machine through a hopper and then into a heated barrel. As the material is heated in the barrel, it becomes a liquid resin, which is injected under high pressure into a closed mold. Once the molten polymer has cooled, the finished part is removed from the mold.
The advanced properties of TPE compounds reduce cycle times, allowing parts to be produced quickly.
9. When should thermoplastic elastomers (TPE) and silicone be used?
Heat is the main difference between TPE and silicone. After TPE is heated, it can be reprocessed. If you are choosing between thermoplastic elastomers and silicone for a product, and it needs to be reworked, you should choose TPE. After heating, silicone cannot be reprocessed or altered.
Say you’re choosing between thermoplastic elastomers and silicone for a product that needs to withstand extremely high temperatures. In this case, silicone is a better choice because its temperature range is much higher than TPE.
10. How to choose a suitable TPE material?
To choose the right TPE material, you should first consider what it is replacing, what material is currently being used, what needs to be improved, or whether there is a price target. Next, be sure to note any functional or performance requirements.
You should then consider how the parts will be manufactured and assembled by injection molding, extrusion or blow molding. Formulations for TPE depend on how the material is processed. For example, suppose a TPE will be over-molded or coextruded onto another material. As a TPE that bonds well to one material may not necessarily adhere to another, over-molding or coextrusion must be considered.
Cost and environmental conditions should also be considered, such as whether the TPE product will be used indoors or outdoors and any temperature requirements.
11. How to choose the right silicone material?
To choose the right silicone, you should consider the properties required for the intended use of the product. In fact, there is no single type of silicone that works for all situations. Instead, many different types have varying degrees of flexibility, durability, and resistance.
When making your selection, consider the desired chemical, mechanical and physical properties of the material.
12. Is thermoplastic elastomer (TPE) safe to use?
Yes, it is safe to use thermoplastic elastomers. Latex is more likely to cause allergic reactions than TPE. There are, however, some people who are concerned about the safety of TPE because it contains chemicals called phthalates. In order to make TPE more flexible, phthalates are added, but they can also pose a health risk.
Studies have linked phthalates to hormone disorders, reproductive problems, and cancer. However, TPE products are generally low in phthalates and pose little health risk to humans. Therefore, TPE can be used legally and is generally considered safe.
13. Is it safe to use silicone?
Yes, silicone is safe to use. Silicones are used in medical, electrical, and other applications. Because silicone is chemically stable, experts say it’s safe and probably non-toxic. In addition, food-grade silicone cookware will not cause harmful chemical contamination of food, according to FDA regulations.
14. Conclusion
This article summarizes TPE vs. silicone and highlights the differences between the two materials as well as their uses and toxicity.
