Re: foam

[Bill Bilkovich <bilko@vistech.net>]

Try this as a three part question, and I assume we are talking about rigid 
foam made by combining MDI (CAS 101-68-8) with a polyol in the presence 
of a blowing agent:
1.  Is there any way to avoid using methylene 
chloride to clean the mixing chamber?  Yes.  You switch from a vane pump mixing chamber to a 
self-cleaning piston system.  I worked with the supplier to a 
refrigerator manufacturer in near Cairo, Egypt so we looked at Italian 
machinery, but this must be available in the US.  You just need to get 
the name of the largest American maker of foam filling equipment.  The 
mixing chamber is swept by a close-fitting piston which complelety 
removes the mix.  Name of this client is confidential but the supplier 
contact information is: Yehia A. Lofti, Fax in Cairo is 202-360-2934.

2.  Is there a way to reduce the use of methylene chloride to clean the 
delivery tip?  You can drastically reduce use by using the piston type 
machinery because the delivery section is very short.  You may have to 
alter the way the filler addresses the mold because the delivery nozzle 
is so short compared to systems with long hoses and hand-held delivery 
nozzles.

3.  Is there an alternative to using methylene chloride for the last 
little bit of cleaning?  A short disposable tip would do it.  I never 
inquired about alternative cleaning chemistries because I did not want to 
encourage continued use of the old filling machinery and here is why.  
Remember that when you clean, you are losing MDI, polyol, blowing agent, 
and methylene chloride.  When you look at the economics of 
buying a new filler, your $ savings are distributed as follows:
	25% from avoided methylene chloride purchase (160 tons/yr in my case)
	36% from avoided MDI losses
	35% from avoided polyol losses
	 4% from avoided blowing agent losses (but this was Freon 11, 
your case will probably use a more expensive HCFC, which this client was 
also going to switch to during implementation).  From this you can see 
that new cleaning chemcials only get at 25% of the savings, would 
probably cost more, and do not get any of the productivity benefits that 
no-clean offers the company.

We should see a lot of need for this type of change with the new 25ppm 
standard for MeCl exposure.  By the way, watch it around MDI.  If you get 
sensitive to this stuff, you might as well move to a stainless steel 
house in the hill country of Texas because it is everywhere.  For example, 
in the glue used to laminate the two layers of the wrapper on the soap you 
would use to wash your arm when you breakout in a rash from MDI exposure.

Sorry to not reply very often P2Techers but I have been working a large 
project on the road and have not gotten my act together to regularly 
access my access provider back in Tallahassee.  Hope to see many of you 
in Denver.

Bill Bilkovich, EQC
3651 Cherry Bluff Ln
Tallahassee, Fl 32312-1001
Fax 904-894-2480 Voice 904-894-2780
bilko@vistech.net


On Fri, 7 Feb 1997, List Manager wrote:

> From: "Richard Yoder, P.E." <nbdc-nics@navix.net>
> To: P2Tech <p2tech@great-lakes.net>
> Subject: urethane foam & mehylene chloride
> 
> P2-techers:
> 
> I know many of you are familiar with two component urethane foam applied 
> through a mixing head gun with a metal tip.  Typical applications include 
> refrigerated boxes, which employ the insulating foam to fill wall 
> cavities, and in this case to provide adhesion in a sandwich 
> construction.  Clean-up of the tip and gun mixing chamber typically 
> utilizes methylene chloride as the solvent.
> 
> Questions: 
> 
> 1.  Since the gun we're looking at now has a commonly used pipe thread 
> which connects the tip, I suspect that there are several vendors for the 
> disposable tips other than the gun manufacturer.  Any idea of where a 
> list might be?
> 
> 2.  I recall seeing guns utilizing "mixing" tips which combine two 
> components in the tip, eliminating the clean up problem associated with 
> the mixing head.  Again, have you seen this type of tip in 2-part 
> urethane foam applications?  Sources/vendors?
> 
> 3.  Is anyone aware of an alternative material that could be utilized as 
> a foam?  Insulating value, density and adhesion are issues. 
> 
> Thanks for your help.
> 
> ry
> 
> -- 
> 
> 
> ******************************************************************
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