Choosing Double Shot Mold Materials for Heat and Chemical Exposure

Choosing a suitable material pairing for a double shot molded part exposed to elevated temperatures and chemicals requires more than identifying compatible materials. Longterm lists ABS+TPU and PP+TPE as hard-and-soft combinations for its double shot molding process, but the available product information does not provide heat limits, chemical-resistance ratings, or comparative test results. Neither pairing can be declared the better choice without testing the specific grades under the part’s actual service conditions.

What the Available Specifications Tell You

The product information confirms that ABS+TPU and PP+TPE can be used as double shot material pairs. It does not establish how either combination performs when exposed to heat, chemicals, or both. Properties can vary by material grade and by the specific substances, temperatures, and exposure durations involved, so selection should be based on the intended application rather than the pair names alone.

Longterm specifies a two-color injection structure, high-precision alignment, optional multi-cavity tooling, and mold steel grades 718H / 1.2738. The stated mold life is up to 800,000 shots. These details describe the tooling and its production capabilities, not the service limits of the finished part.

How to Validate a Material Pairing

Before approving a combination, document the operating temperature range, chemicals involved, exposure duration, and other relevant use conditions. Ask the material supplier or manufacturer to identify the exact grades and provide supporting compatibility information. Then test representative molded samples against agreed acceptance criteria before authorizing production.

The listed quality checks include a mold trial run, dimensional testing, and pre-shipment inspection. These steps address the molding process and part dimensions; the product information does not state that they include heat-aging or chemical-resistance testing. Confirm any application-specific tests separately.

Options and Project Details

Tooling Experience and Company Information

Longterm reports producing a double shot overmolding mold for a consumer-electronics shell for a client in France. The client feedback described good alignment and stable trial samples. This example reflects tooling experience, but it does not provide test evidence for heat or chemical exposure.

The company lists ISO 9001:2015 certification for the design, manufacture, and sale of precision molds and the sale of plastic products. Longterm Manufacturing Solutions Limited was founded in 2010 and serves customers in the United States, Europe, Australia, and other international markets. Its 50-person team includes seven experienced engineers and provides mold design, tooling, precision machining, mold manufacturing, and parts production.

Longterm Manufacturing Solutions Limited

Frequently Asked Questions

Which combination is more suitable for heat and chemical exposure?

The available information does not compare the heat or chemical resistance of ABS+TPU and PP+TPE. It supports both as compatible double shot pairings, but further grade-specific evidence and testing are needed to choose between them.

Are environmental tests included in the listed inspection steps?

No heat-aging or chemical-compatibility tests are specified. The stated checks are a mold trial run, dimensional testing, and pre-shipment inspection. Ask the manufacturer to confirm whether additional testing can be arranged.

What should be settled before placing an order?

Confirm the exact material grades, the expected operating and exposure conditions, and the criteria for sample approval. The stated minimum order is one mold set, and the listed lead time is 25–40 days.

Recommendation

Both ABS+TPU and PP+TPE are identified as double shot molding options, but the supplied specifications do not show which is more resistant to heat or chemicals. Request information for the exact grades under consideration and validate molded samples in conditions representative of the application. Longterm offers custom double shot overmolding molds, online technical support, and a one-set minimum order. For technical details, contact rogerluo@longterm-mold.com.