Process for producing improved phenolic foams from phenolic resole resins
AssigneeBP Chemicals Limited
InventorsMichael A. Barcroft, Kathryn S. Gould, David R. Johnstone, David C. Wilson
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Abstract
This invention relates to novel blowing agents comprising a blend of (A) perfluoro- or partially fluorinated-(cyclo)alkanes and (B) one or more of hydrogenated chlorofluorocarbons, hydrogenated fluorocarbons and a low boiling (cyclo)alkane. These blowing agents perform as well as the conventionally used CFC's but are user friendly and do not have the adverse effect of depletion of the ozone layer. These blowing agents are particularly suited for use in producing foams from synthetic polymers and resins, especially phenolic foams of very low and stable thermal conductivity.
Claims9
A process for producing a phenolic foam in the presence of a blowing agent composition, said blowing agent composition comprising a blend of:
- (A) at least one flurocarbon component having the general formula:
- C.sub.n H.sub.x F.sub.y (I)
- wherein x=0, or a whole number from 2 to n/2, such that:
- (a) for a cyclic fluorocarbon:
- when x=0, n=3 to 10 and y=2n, and
- when x=a whole number from 2 to n/2,
- n=4 or higher, and
- y=2n-x,
- whereby x+y=2n;
- and
- (b) for an open chain fluorcarbon:
- when x=0, n=2 to 10 and y=2n+2,
- when x=a whole number from 2 to n/2,
- n=4 or higher,
- y=(2n+2)-x;
- and
- (B) at least one other component selected from:
- (a) a hydrogenated chlorofluorocarbon (hereafter ("HCFC"),
- (b) a hydrogenated fluorocarbon hereafter (HFC") having the general formula:
- C.sub.r H.sub.p F.sub.q (II)
- wherein:
- r=1 to 3,
- p=1 to 4, and
- q=(2r+2)-p for an open-chain HFC, and
- q=2r-p for a cyclic HFC,
- such that:
- p+q=2r+2 for an open chain HFC, and
- p+q=2r for a cyclic HFC;
- and
- (c) an alkane or cycloalkane having a boiling point below 120.degree. C.
The process as claimed in any one of the preceding claims wherein said at least one other component is a HCFC selected from the group consisting of:
- HCFC 123 which can be represented by CF.sub.3 --CHCl.sub.2,
- HCFC 141b which can be represented by CCl.sub.2 F--CH.sub.3,
- HCFC 124 which can be represented by CHClF.sub.2,
- HCFC 142b which can be represented by CH.sub.3 CClF.sub.2,
- HFC 225ca which can be represented by CHCl.sub.2 --CF.sub.2 --CF.sub.3, and
- HCFC 225cb which can be represented by CClF.sub.2 --CF.sub.2 --CFClF.
Dependencies are inferred from the claim text.