Small-cell foam? 7

[patprimmer]

Or you might find out the hard way that I am full of BS. ;-)

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

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

for site rules

 

[btrueblood]

BS, BS...That's Boron Sulfide? Taking that for a yeast infection or something? Hmm...maybe too much info. already.

 

[MacGyverS2000]

But Pat's is a sourdough yeast infection...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[suselinux]

Theophilus

you may want to talk to someone who does RIM process

they could at the very least advise you on materials if not supply your parts.

 

[Theophilus]

Thanks, I'll consider that, suselinux. Just getting in from the weekend and starting on the whole sourcing side of things.



Jeff Mowry

http://www.industrialdesignhaus.com

A people governed by fear cannot value freedom.

 

[Demon3]

Thought I'd write a couple of lines about the EVA topic. As Pat mentioned, EVA is a copolymer mainly comprised of polyethylene with a few % vinyl acetate comonomer added to improve flexibility, lower Tg and improve elongation to break. It is commonly added to PE cable formulations to improve the elongation to break. The EVA is also added to PE and foamed to make those synthetic wine corks. Other polymers can be added to PE to do a similar flexibilizing job. One example is polyethylene-co-butylacrylate (available from Borealis) another is SBS, e.g. Styroflex 3G66 from BASF.

You can also make a microcellular foam by adding CO2 during injection molding using patented processes such as mucell (

http://www.trexel.com/)

or a similar process patented by the IKV in Germany.

When foaming it's a very good idea to add 1 weight % of fine (2 micron) calcium carbonate as that gives the foam cells somewhere to nucleate and start growing to give a more even, finer foam. Good grades to try would be Carbital 110 from Imerys or Omyacarb 2AV from Omya.

Chris DeArmitt

http://www.phantomplastics.com

Consulting to the plastics industry

 

[patprimmer]

Chris

As always, a wealth of knowledge.



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]

Thanks Pat. I enjoy helping people. My wife is having contractions right now so I expect a small new plastics expertess to be born today or tomorrow.

Chris DeArmitt

http://www.phantomplastics.com

Consulting to the plastics industry

 

[Theophilus]

Wow, thanks, Chris!

And--congratulations!



Jeff Mowry

http://www.industrialdesignhaus.com

A people governed by fear cannot value freedom.