MXPA00002967A - 142b/124 blowing agent blends - Google Patents

Abstract

Nonflammable foam blowing agent blends of 142b or 124 are provided, as are polyol premixes and polyurethane foam compositions containing such blends.

Description

MIXTURES OF BLOWING AGENT 142W124 IR 3573 BACKGROUND OF THE INVENTION This invention relates to foam blowing agent mixtures of 1-chloro-1,1-difluoroethane ("142b") and 2-chloro-1,1,1-tetrafluoroethane (" 124"), more particularly to nonflammable mixtures containing up to about 70% by weight of 142b and at least about 30% by weight of 124 and to nonflammable mixtures and polyurethane foam compositions containing said mixtures. Heretofore, 142b has been frequently listed in the patents as a potential polyurethane foam blowing agent, but its use has usually decreased due to its known flammability. However, with the anticipated progressive reduction of the main commercial blowing agent, 1, 1-dichloro-1-fluoroethane ("141 b"), the market has a need for other foam blowing agent alternatives.

BRIEF SUMMARY OF THE INVENTION. Non-flammable foam blowing agent compositions are provided, which comprise up to about 70% by weight of 142b and at least about 30% by weight (preferably at least about 40%, more preferably at least about 50%) of 124, as well as non-flammable foam premix compositions containing such foam blowing agent compositions. The constitution of the premix composition depends on the percentage of 124 in the blowing agent mixture. Where at least about 50% of 124 is present, the foam blowing agent may be present as part of an A-side premix with an isocyanate (preferably a polymeric methylene diisocyanate) or, preferably, as part of the premix of side B with any conventional polyol. Where at least about 40%, but less than about 50% of 124 is present in the mixture, the foam blowing agent can be present as part of an A-side premix together with a polymeric methylene diisocyanate or as part of the side B with a polyol selected from the group consisting of polyester polyols and polyether polyols based on aromatic amine. Where at least about 30%, but less than about 40% of 124 is present, the blowing agent mixture is preferably part of an A-side premix together with a polymeric methylene diisocyanate. The invention is also directed to polyurethane foams compositions containing such foam blowing agent compositions and foam premix compositions.

DETAILED DESCRIPTION It has now been found that mixtures of 142b / 124 containing at least about 28-30% by weight of 124 provide flammable mixtures useful as a blowing agent for polyurethane foam. Due to the closed boiling points of 142b (-9 ° C) and 124 (-12 ° C), these mixtures do not tend to fractionate, unlike a mixture such as 142 b plus chlorodifluoromethane ("22"). In addition, the addition of 124 to 142b has other benefits, such as the decrease in ozone depletion potential and global warming potential of the mixture, as the solubility of the mixture in polyols increases. Mixtures containing less than 28% of 124, when mixed with most polyols and isocyanates, can result in flammable mixtures in the headspace above the premixes. At the 124 levels between about 28 and 40%, the best results (flammability) are obtained when the mixture is premixed with a polymeric methylene diisocyanate such as Mondur 489, a diphenyl diisocyanate of polymeric methane available from Bayer Corporation. At the 124 levels between about 40 and 50%, a non-flammable premix alternative is a mixture of the blowing agent with a polyester polyol or a polyether polyol based on an aromatic amine. Examples of polyester polyols are Terate 2541 and Terate 254, available by Hoechst Celanese, and PS 2502a, available from the Stepan Company. PL824 and V391 are examples of polyether polyols based on aromatic amine, available from BASF Corporation and Dow Chemical Company, respectively. At levels of above about 50%, the blowing agent mixture can be premixed with any conventional isocyanate (to form an A-side premix) or, preferably, with any conventional polyol (to form a B-side premix) Examples of other conventional polyols are polyether polyols based on glycerin (such as V270, available from Dow Chemical Company) and polyether polyols based on aliphatic amine (such as V800, available from the Dow Chemical Company). dividing the blowing agent mixture between side A and side B. In the premix compositions, the total amount of blowing agent is typically present in a concentration range of about 2-60% by weight (preferably 10- 40% by weight and more preferably approximately 20-30% by weight), based on the weight of the polyol or isocyanate In the polyurethane foam compositions, the effective concentrations of the polyurethane ezclas are typically about 0.1-25% by weight (preferably 0.5-15%) based on the weight of the total polyurethane foam formulation. The other components of the premix and foam formulations may be those that are conventionally used, whose components and their proportions are well known to those skilled in the art. For example, catalysts and surfactants are typical components of the B side. Some examples of typical components and mg procedures are set forth, for example, in Research Description 40137 (9/97). Also, water is frequently used as a co-blowing agent in the manufacture of polyurethane foam.

The practice of the invention is illustrated in the following non-limiting example, using the B-side premix containing polyol, surfactant, catalyst and blowing agents. The total formulation used (which has an Iso index of 1 15) is set forth in Table I, all the listed materials being commercially available. In Table I, L-6900 is a silicone surfactant available from Witco Corporation and PC-8 is dimethylcyclohexyl amine, a catalyst available from Air Products.

Table I Component Parts by Weight Polyol PL-824 100 Surfactant Agent L-6900 1.5 Catalyst Amine PC-8 2 Water 1 .5 124 14.8 142b 14.1 Monduro 489 133 A foam was made from this formulation by mixing sides A and B in an impact mixing head, after which the mixture was poured into a mold. The ASTM C518 procedure was then followed up to the initial measurement (3864.5 joules.cm / m2.hr. < íF) and the K factors matured (4383.6 joules.cm / m2.hr. F after two months) to 24 ° C of the resulting foam, which had a density of 33.7 kilograms per cubic meter.

Claims (6)

1. CLAIMS 1. A foam blowing agent composition, characterized in that it comprises up to about 70% by weight of 1-chloro-1,1-difluoroethane and at least about 30% by weight of 2-5 chloro-1, 1, 2- tetrafluoroethane.
2. 2. A foam blowing agent composition, characterized in that it comprises up to about 60% by weight of 1-chloro-1,1-difluoroethane and at least about 40% by weight of 2-chloro-1, 1, 2 -tetrafluoroethane.
3. 3. A foam blowing agent composition, characterized in that it comprises up to about 50% by weight of 1-chloro-1,1-difluoroethane and at least about 50% by weight of 2-chloro-1, 1, 1, 2-tetrafluoroethane.
4. 4. A foam premix composition, characterized in that it comprises polymeric methylene diisocyanate and the foam blowing agent according to claim 1. 5. A foam premix composition, characterized in that it comprises the foam blowing agent composition according to claim 2 and a polyol selected from the group that 20 consists of polyester polyols and polyether polyols based on aromatic amine. 6. A foam premix composition, characterized in that it comprises a polyol and the foam blowing agent composition according to claim 3. 7. A composition "of polyurethane foam, «-jt-a? Aia-8-? characterized in that it comprises an A side containing the foam premix composition according to claim 4 and a B side containing a polyol. 8. A polyurethane foam composition, characterized in that it comprises an A side containing polymeric methylene diisocyanate, a B side containing a polyol selected from the group consisting of polyester polyols and polyether polyols based on aromatic amine and the composition of foam blowing agent according to claim 2, said blowing agent composition being present on either side A or side B. 9. A polyurethane foam composition, characterized in that it comprises an A side containing methylene diisocyanate polymer, one side B containing a polyol and the foam blowing agent composition according to claim 3, said blowing agent composition being present either on the A side or on the B side. 10. A polyurethane foam composition , characterized in that it comprises a side A containing an isocyanate and a side B containing the foam premix composition according to the claim
5. 5. 1 1. A polyurethane foam composition, characterized in that it comprises an A side containing an isocyanate and a B side containing the foam premix composition according to claim
6. 6.