Economical choice of high heat temp resistant material

[amirsarmad]

Hello

I am in the process of designing a tray that can be used repeatedly in the oven for warming up food. The tray material would have to be thermoplastic and injection mold-able.

The tray would not be disposable so it would have to be put into a dishwasher for cleaning.

It would also have to be white and not turn yellow when exposed to heat.

the average operating temp would be between 180 Celsius to 200 Celsius (356 f to 393 f). It would also need to not emit any potentially hazardous gases at these temps.


I have considered a variety of polymers and would like your opinion on what is the most economic route to go with or whether there is an alternative that I have not gone over.

1) PA6 GF 30%-45%
2) PA 66 GF 30%-45%
3) PPS
4) PBT (suspect to material degradation in dishwasher)
5) PEEK, PEK, Family
7) PEI
8) PPE
9) PPE/PA blend

I think PA6 is perhaps the most economical and viable router but am open to suggestions or confirmations.

Thank you in advance

 

[Pud]

Any good:

http://uk.news.dupont.com/contenu/zip/55080.doc

?

H

http://www.tynevalleyplastics.co.uk

 

[IRstuff]

Perhaps you should simply head down to the local supermarket and peruse the various existing products that have the features you're looking for. Costco's roasted chicken containers appears to tolerate high temperatures quite well and are machine washable.

TTFN

FAQ731-376

 

[Demon3]

Nice one IRstuff. It amazes me too that people don't think to see what is already used successfully in the marketplace for the exact same application.

When I worked at Electrolux they were searching for a plastic that can take machine washing. I said, well the clothes do for one thing (polyamides, polyesters etc.) and so do those balls that you dose the liquid detergent in.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[patprimmer]

All plastic cookware I have seen has been for microwave and maximum temperature tends to be about 130 deg C. Some better quality ones are rated to 160 deg C

The lower temperature Microwave dishes are almost exclusively mineral filled PP. The better ones are polysulphone.

In my opinion

re nylon 6 won't work for several reasons.

1) Glass filled nylon 6 will not get a food contact rating due to the coatings on the glass and free caprolactum that can leach from the moulding.

2) It will yellow at 200 deg C.

3) It will be marginal re HDT

Re nylon 6.6

1) As it has a higher HDT itmay get the temperature rating with a food contact reinforcement. Maybe special glass, maybe wollastonite, maybe mica. Maybe not.

2) It will still yellow with age, even slightly faster than type 6.

Re PPS

I don't think it has food contact approval. If it does it should be suitable. There are two types. One is a lot better for light colours.

Re PBT

PBT is doubtful at over 180 deg C

Re PEEK family and PEI

They should be suitable if you can wear the cost.

Re PPE/PPO and blends

May be OK, but are susceptible to solvent stress cracking in fats and oils often present in cooking. They will be marginal re HDT

Have you considered nylon 4.6

Have you considered aromatic nylons like Grivory or Zytel HTN or Reny or Trogamid.



Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[amirsarmad]

Patprimmer:

Thanks for the info. Ive checked all your reccomendations and this puts nylon out of the question.
I will look into aromatic nylons.

IRSTUFF:

Ive already checked my local department stores, They mainly used CPET which is diposable (Degrades in humdidty) and Aluminum Trays. Any help would be useful.

DEMON 3:

Polyesters dont work well in dishwasher environments and prone to Hyrdrolysis

PUD:

Thank for the help, this seems Ideal I will check into it

 

[Demon3]

Sorry, I was confusing this with a washing machine. Ironically I worked on plastics for dishwasher use when I was at Electrolux. You're right about hydrolysis.

I suggest you check out syndiotactic polystyrene sPS. It is inert like polystyrene but because it's crystalline it has an HDT of 240-260C and good chemical resistance (note normal PS has lousy chemical resistance but again the crystallinity helps dramatically). It has very low water uptake.

It used to be made by Dow but is now available from Idemitsu under the name Xarec. In the US ask for Tom Fiola, very helpful guy. If you want his direct telephone number and e-mail I can provide it if you e-mail me (can't post it here).

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[patprimmer]

I am pretty sure Trogamid/Grilamid and Ultem are all used on oven light lenses and inside dishwashers.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[Demon3]

Here's a link to information about Xarex sPS.

http://www.idemitsu.com/products/petrochemicals/engineering/polystyrene.html

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[unclesyd]

Demon3,

I don't see any information on food grade material on the referenced site. It looks like a 150°C is the upper limit on any resistance information.

amirsarmad

Getting a plastic to withstand your temperature isn't going to be cheap. I believe you are going to have to go with a coated paper or a ready made container, which in itself is expensive. The plastic containers in the first link are good to 400°F with the appropriated precautions. This is
about the upper limit of the all plastic heat and serve containers.

http://www.plasticcontainercity.com/ovenable-containers.htm

http://www.policartausa.com/uploads/bakeinbag.pdf

http://www.mqplastics.com/polyester-shrink-film-cooking-bags.php