PP, TPE and silicone cannot be ranked with one “heat-safe and food-safe” score. PP may be efficient for rigid containers and hinges, TPE for flexible seals and overmolds, and silicone for flexible parts exposed to higher temperatures—but the exact grade, food type, time/temperature and cleaning cycle determine suitability.
Compare the three materials under the same specification
| Factor | PP | TPE | Silicone elastomer |
|---|---|---|---|
| Typical role | Rigid/semi-rigid body, lid, living hinge | Flexible seal, valve, grip or overmold | Flexible seal, membrane, utensil or high-temperature component |
| Process | Thermoplastic injection molding | Thermoplastic molding; grade-specific overmolding | Liquid-injection or compression molding with curing |
| Heat screening | Grade and load dependent; creep matters | Wide variation among families and compounds | Many grades tolerate higher service temperatures |
| Sealing behavior | Limited elastic recovery compared with elastomers | Broad hardness range; compression set is grade dependent | Often good elastic recovery; exact grade and cure matter |
| Bond/assembly | Can be the rigid substrate | Must be matched to substrate or mechanically retained | May require primer, bonding system or mechanical retention |
| Reprocessing | Clean molding scrap can often be reprocessed under controlled limits | Clean scrap may be reprocessable; effect on properties must be controlled | Cured silicone does not remelt like a thermoplastic |
These are selection tendencies, not universal property limits. Use the supplier’s data for the exact grade, color and molding condition.
“Heat resistant” needs a load and a time
A material can retain shape briefly in hot water yet creep under a continuous sealing load. Distinguish:
- short hot-fill or cleaning exposure;
- continuous service temperature;
- dishwasher, boiling or steam cycles;
- mechanical load during heating;
- thermal aging over the target lifetime; and
- dimensional and sealing criteria after cooling.
For PP, evaluate creep and hinge fatigue. For TPE and silicone seals, measure compression set or seal force after conditioning. A material’s melting point or a generic maximum-use temperature is not enough to predict the finished part.
Food-contact compliance is use-specific
The FDA states that food-contact substances must have an appropriate regulatory basis for their intended conditions of use. An effective Food Contact Notification can be specific to the named manufacturer or supplier. In the EU, Commission Regulation (EU) No 10/2011 applies to plastic materials and articles within its scope; silicone elastomers may require a different national or market-specific compliance route. Do not assume that documentation for PP or TPE automatically covers silicone, or vice versa.
Use this selection sequence
- Define food types, contact time, maximum temperature and repeated-use cycles.
- Define the mechanical function: rigid structure, living hinge, seal, valve or soft-touch area.
- Compare exact supplier grades and their market-specific documentation.
- Review wall thickness, sealing geometry, bond strategy and cleanability.
- Mold representative parts in the final color and material stack.
- Test migration/compliance as required and verify dimensional, seal and appearance performance after repeated conditioning.
- Freeze approved materials and change-control requirements.
Common specification mistakes
- Writing only “food-grade PP/TPE/silicone” without a manufacturer and grade
- Using one heat limit for all loads, times and geometries
- Ignoring colorants, overmold substrate and adhesives
- Assuming a supplier declaration eliminates finished-article validation
- Choosing the softest elastomer without testing compression set or tear
- Comparing material cost while ignoring cycle, cure, tooling and assembly
For a molded food-contact component, send the CAD model, material candidates, food/contact conditions, cleaning cycle, annual quantity and acceptance tests. CKMOLD can review plastic material and molding requirements, hard-soft interfaces and DFM risks. Use the RFQ page for tooling feedback; final compliance remains with the product owner and qualified regulatory specialists.