r/Composites

We are seeking a thermoplastic elastomer for direct overmolding onto a glass-fiber-reinforced nylon substrate. Our main requirements are strong adhesion without a separate adhesive or primer, and resistance to four specified lubricating greases over an operating temperature range of −40°C to +80°C.

Our application requirements are as follows:

1. Substrate and molding process

- Substrate: PA66/6 with 30% glass fiber reinforcement (PA66/6-GF30).

- The TPE is to be injection-overmolded directly onto the nylon component within the mold.

- No separate glue, adhesive layer, or primer is to be used.

- We require strong interfacial adhesion to the nylon, rather than retention solely through mechanical interlocking.

2. Grease exposure

The overmolded component must withstand contact with each of the following greases:

- BBZ — understood to be Shell Rhodina Grease BBZ.

- 585K Plus — understood to be FUCHS GLEITMO 585 K PLUS.

- “Krupp 41-141” — understood to refer to Klüberplex BEM 41-141; the exact identity is to be confirmed.

- “Mobil 460” — possibly Mobil SHC Grease 460 WT; the exact product designation is to be confirmed.

Please let us know what product data sheets, safety data sheets, or grease samples you would need to assess compatibility accurately.

The TPE should resist excessive swelling, softening, tackiness, cracking, and degradation during grease exposure. Most importantly, the TPE-to-nylon bond must remain strong after exposure, without peeling or delamination.

3. Operating temperature and other properties

- Required operating temperature range: −40°C to +80°C.

- No specific Shore hardness is currently required.

- We have no separate requirements for bending performance, sealing performance, or abrasion resistance.

- Hardness may therefore be selected to achieve the best combination of nylon adhesion, grease resistance, and reliable molding performance.

4. Material recommendatio

Please recommend the most appropriate formulation for our application, including a customized formulation if necessary.

5. Technical information and validation

Please provide, where available:

- Recommended commercial grade names and current technical data sheets.

- Adhesion or peel-strength results on glass-filled PA66, PA6, or PA66/6, including substrate grades, specimen preparation, and molding conditions.

- Compatibility results for the four specified greases, or relevant supporting oil/grease resistance data, including exposure temperature and duration.

- Adhesion retention after grease exposure, together with swelling and hardness-change results.

- Low-temperature data supporting use at −40°C.

- Recommended drying conditions, melt temperature, mold temperature, nylon insert temperature, and other processing conditions needed for strong adhesion.

- Any restrictions concerning mold-release agents, nylon additives, moisture conditioning, or storage of nylon inserts before overmolding.

If grease-specific data are unavailable, please recommend a qualification program using our actual nylon and greases. We would particularly like to evaluate grease exposure at +80°C followed by adhesion testing and thermal cycling between −40°C and +80°C. Please advise appropriate test durations and

I'm part of a prototype car team that makes their chassis out of carbon fiber. We've run into a lot of problems when making the lower body of the car, especially with choosing the right sandwich material for our stackup.

Last year, we used Nomex (cardboard honeycomb structure, 1/8th inch thick) as our sandwich material, and did 3 layers carbon fiber as the base layer, and 3 layers on top. For the layup last year, we cured the bottom layer first, then put the nomex on top of that, and then coated the top of the structure with epoxy+filler, then re-layed up with carbon fiber. The carbon fiber had a hard time sticking to the nomex structure due to the lack of surface area, and I'm unsure if some of the resin travelled into the nomex structure.

We use dry carbon fiber, and we use room-temp curing epoxy resin, and we're not looking to using prepreg, and prepreg adhesive films lowk too expensive for us (we're on a budget).

What can we do to improve carbon fiber layup for us? Do we cure both the top and bottom parts of the sandwich panel, and then do the layup for the nomex separately (with the filler)?