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Looking for a rubber material with these characteristics...

Looking for a rubber material with these characteristics...

Looking for a rubber material with these characteristics...

(OP)
The material needs to have the following characteristics:
  • Able to be overmolded onto a polypropylene part (needs good bonding)
  • FDA direct food contact approved
  • Oil resistant (our current material from GLS/Polyone absorbs oil and becomes gummy)
  • Abrasion resistant (think food crumbs/sugar/etc)
  • Withstand temps up to 220 degF
  • Needs to be able to be colored to white
  • Needs a decent coefficient of friction
Thanks ahead of time.

RE: Looking for a rubber material with these characteristics...

Chemlok Division of Lord Corporation has a 250 chemical adhesive (used without primer) they suggested and where that isn't satisfactory, the polypropylene inserts can be chemically etched before bonding to promote bonding. Ordinary starting places for oil resistance would be nitrile or neoprene. There are a lot of nitrile recipes which are formulated from the FDA GRAS (Generally Regarded as Safe) register. If I can get your e-mail I can send you the Chemlok data sheet or you can contact Gayle Rakosky at Chemlok (919) 468-5981 ext. 6456.

Terry Garrity
Indiana Rubber & Plastics Company, Inc.
Arcadia, Indiana
www.indianarp.com

RE: Looking for a rubber material with these characteristics...

(OP)
First off, thank you for replying. I think I need to clarify my post/needs and perhaps even post in another forum after realizing that I forgot to specify that I specifically need a material that can be run in a traditional Thermoplastic Injection Molding machine. Thermosets are, unfortunately, out of the question. Perhaps I should post in a polymer engineering forum instead? Thank you again for your input.

RE: Looking for a rubber material with these characteristics...

Exxon-Mobil Geolast would perhaps be a fit. It is a thermoplastic vulcanizate that processes in plastics injection machinery. Problem will be bonding but that is for Chemlok to advise on. Why does it need to be run as injection? Due to melt temp of the polypro? We do some plastic to rubber bonding. Can you look at some other resins to bond to besides polypropylene?

Terry Garrity
Indiana Rubber & Plastics Company, Inc.
Arcadia, Indiana
www.indianarp.com

RE: Looking for a rubber material with these characteristics...

(OP)
This new material would be utilizing existing molds and base parts. We would not be interested in changing the base resin nor utilizing anything other than the current molds as several parts are affected.

RE: Looking for a rubber material with these characteristics...

All I can say is good luck with using the same moulds and techniques. In my experience, even the slightest change to a compound will affect processes down the line. You are also exposing yourself to possible dimensional problems if you use the same tooling. Be prepared for some modifications being required.

RE: Looking for a rubber material with these characteristics...

Problems down the line and change in shrink may or may not be a problem...probably not if it's a simple part like a bumper for example; BUT, coloring Geolast may be a major challenge as I believe the natural color version is tan. Change in shrinkage of course has to be considered but only if tolerances are tight.

Terry Garrity
Indiana Rubber & Plastics Company, Inc.
Arcadia, Indiana
www.indianarp.com

RE: Looking for a rubber material with these characteristics...

(OP)
Change in shrinkage and/or dimensional tolerance isn't a concern here (the use of the part is rough). When I said keeping the same molds and techniques, I only meant that it needs to be able to run in a similar mold setup. New processing parameters would of course be created.


I will check out Geolast.

RE: Looking for a rubber material with these characteristics...

(OP)
Can anyone confirm whether or not Geolast is FDA approved for direct food contact? I can't seem to find anything on the web. Working on contacting Exxon.

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