TPE Overmolding, Bonding and Substrate Considerations

Design engineers choose TPEs for improved ergonomics, enhanced grip performance, improved aesthetics, and critical impact protection. Applications that benefit from TPE overmolds range from consumer goods to medical instruments to industrial tools and can include knobs, handles, gaskets, seals and grips.

Benefits of Overmolding

With improvements in material technology of TPE, overmolded part designs have become less dependent on mechanical interlocks to hold a TPE in place. Chemical bonds between TPE and rigid materials offer improved part integrity and longevity while eliminating the need for adhesives or surface pre-treatments. System performance can be further optimized by including both chemical and mechanical bonds in the part design. The net benefit has greatly expanded design freedom.
Chemical bonds in overmolding:
a) Improve product function;
b) Increase margins;
c) Expand product differentiation;
d) Enable new design innovation

Optimal Bonding Materials

Molders using multi-shot molding in combination with TPEs need to have a thorough understanding of bonding, and how to select both TPE and rigid substrates does affect bond strength. GainShine Plastic Technology offers an expansive line of TPEs for bonding to specific engineering resins and assistance in selecting the ideal grades.

Know more: http://www.gainshine-tpe.com/news/TPE-Overmolding-Bonding-and-Substrate-Considerations.html

Thermoplastic Elastomer Film (TPE) – Offers high elasticity with good processability

Thermoplastic elastomers combine the mechanical properties of rubber-based materials (e.g. high elasticity, abrasion resistance, and friction) with the good processability and recyclability of thermoplastics. This TPE film can be stretched up to 600 percent before it breaks. It is temperature resistant from -50 °C to 100 °C (unstretched material) and has good chemical and UV resistance. It is food safe and does not contain latex (to which some people are allergic).

Used for:
TPE film is used to make flexible and waterproof diapers and for elastic straps for medical products that come in contact with the skin.

Details:
TPEs are a broad category of elastomeric materials; the sample is made from a TPE variant called SEBS (Styrene-Ethylene/Butylene-Styrene). TPEs are difficult to glue but are routinely moulded onto rigid plastics to give handles a better grip.

Learn more: http://www.gainshinetpe.com/thermoplastic-elastomer-film-tpe-offers-high-elasticity-with-good-processability.html

Do you really know the difference between TPE and TPR?

Both TPE and TPR belong to the Family of Thermoplastic Elastomers. At present there is no defined industry standard, so many people are confused about them. TPE and TPR are certainly different.

TPE is the abbreviation of "Thermoplastic Elastomers".
TPR is the abbreviation of" Thermoplastic Rubber / Resin"

TPE are modified from SEBS base material, while TPR are usually modified from SBS.

SEBS is the product of hydrogenatedSBS ("hydrogenation" means molecular hydrogen is introduced into unsaturated molecules in the special reaction conditions, making the molecular structure become saturated). SEBS is with a saturated molecular structure, and its anti-aging, yellowing resistance, heat resistance, corrosion resistance is better than SBS. Therefore the related performances of TPE are also better than those of TPR. 

The difference between TPE and TPR: the surface of TPE is matte, with light astigmatism, but the particles of TPR have reflective glossy surface, reflection is obvious particularly on transparent TPR. TPE feel smoothly and comfortable, but TPR are somwhat more viscotic, especially when temperature is around 30 to 40 deg C. TPR are usually used in products on which gluing with adhesives is required, such as shoes, handicrafts, toys and dolls, etc., because of the tight bonding TPR can achieved with adhesives, while TPE almost do not react with adhesives. TPR are also suitable for products on which coloring or glossy surface are required. 

TPE and TPR have the flexibility of plastics and rubber. The unsaturated molecular structure of TPR molecules is similar to that of rubber, therefore they feel elastic as rubber does. Combustion difference between TPR and TPE: TPE will release thin smoke from burning, while TPR will release relatively thicker and darker smoke from burning.

http://www.gainshine-tpe.com/news/Do-you-really-know-the-difference-between-TPE-and-TPR.html

Thermoplastic elastomers for Auto Industry

Thermoplastic elastomers offer many advantages to car manufacturers. It gives gear sticks and steering wheels their smooth touch. Thanks to their good compression set values and processability with 2C injection moulding, TPE is an attractive option for car window trims. The resistance to oil and grease on offer for example with GainShine makes the material even suitable for use in the engine compartment.

We provide TPEs that meet all relevant requirements, including SGS and Reach test certificates.

Properties:
Odourless
Good weather resistance
Resistant to oil and grease
Fast cost-effective processing
Vibration-damping
Excellent adhesion with all conventional hard components
Abrasion-resistant

Typical applications:
Control elements
Airbags
Anti-slip mats
Window trims
Cowl panels
Spoilers
Seals
Air duct components

Ten Tips on Overmolding

• Match compatibility of TPE and substrate.

• Minimize peeling with sharp transitions in shut-off design.

• Avoid trapping air in cavities via appropriate venting.

• Balance TPE thickness with Shore A hardness for desired “feel.”

• Maintain TPE melt temperature at the level that optimizes adhesion.

• Dry moisture-sensitive materials.

• Select color-concentrate carriers that are compatible with both the TPE and substrate.

• Be aware of liabilities of smooth surface textures.

• Keep the TPE flow-length/part- thickness ratio below 150:1.

• Design gating with good adhesion in mind.

Read more: http://www.gainshinetpe.com/ten-tips-on-overmolding.html