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Cheap polymer with high glass transition temperature

Cheap polymer with high glass transition temperature

(OP)
Hi All,

I am designing an enclosure for some electronics that will get fairly hot. I had originally used ABS for this and find it deforming. I see that polycarbonate is much better. Does anyone have a recommendation comparable in price to polycarbonate and abs that might be a better choice?

Thanks

RE: Cheap polymer with high glass transition temperature

Thermoset resins are used at high temperatures. Some enclosures are made from phenolic molding compounds. All the common thermoplastics soften at pretty low temperatures. Nylon or PET (polyester) are some of the higher temp thermoplastics.

RE: Cheap polymer with high glass transition temperature

What is "fairly hot"?

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: Cheap polymer with high glass transition temperature

(OP)
I have seen internal wall temps of 100 C, but I think we will be closer to 80 C

I should have added that these are injection molded parts. Cheap thermoplastics preferred.

Thanks

RE: Cheap polymer with high glass transition temperature

To echo Compositepro's suggestion, we routinely use nylon for heat cured paint fixtures at 120 C for 2 hour cyclical durations with no problems.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

RE: Cheap polymer with high glass transition temperature

Yes ABS is not a good choice for higher temps at all..

I've been using Lexan 940 polycarbonate with good results for electrical enclosures...
UL RTI of 120-130deg C (<-- this is what UL will use during thermal testing to determine suitability.. don't exceed that and good to go)
Vicat softening 140+ deg C
V-0 flammability down to 1mm thickness

RE: Cheap polymer with high glass transition temperature

There is high heat ABS e.g. Terluran HH which is more resistant but I agree with mcgvr that polycarbonate is better because it has way higher HDT and is flame retardant. The only caveat is that polycarbonate is not resistant to oils and cleaning detergents and will break if exposed to such liquids.

Chris DeArmitt PhD FRSC
President

Plastic materials consultant to the Fortune 100
www.phantomplastics.com

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