CA2303709C - C3 to c5 polyfluoroalkanes propellants - Google Patents

Abstract

Polyfluoroalkanes of 3 to 5 carbon atoms are used as propellants in sprayable compositions or in the preparation of plastic foams and in the electrical industry as cleansing and degreasing agents.

Description

' CA 02303709 2000-04-11 y This application is a division of co-pending application 2,009,169 filed on February 2, 1990.
The present invention relates to the use of C3 to C3 polyfluoroalkanes comprising at least two fluorine atoms as propellants, especially for aerosols and in the production of plastic foams.
The use of fluorochlorohydrocarbons, for example trichlorofluoromethane, dichlorodifiuoromethane and trichlorofluoroethane, as propellants for the above purposes, is known. According to more recent studies, the chlorine content of cenventicnal propellants damages the ozone layer of the earth's atmosphere (see J.F.D. Mills, Cell. Polym. ~, 343 (I987) and F.S. Rowland et al., Nature ~, 8 (19?4)); for this reason limits have been - specified for the amounts of fluorochlorohydrocarbons pro-duced. The need has therefore arisen for chlorine-free propellants.
We have now found that those poiyfluoraalkanes of the formula CZ3_CYz_R ( I ) wherein 2d the radicals 8 located on the same carbon atom stand for hydrogen and/or fluorine, the radicals Y located on the same carbon atom stand for hydrogen, fluorine and/or CFA, and R stands for CHZF, CHF=, C8" CFs, CFs-CH" CFzCHzF, 2 5 C$a-C$3 s ~-~z-~~ ~_ -~ ( ~3 ~ ~3 and Wherein the polyfluoroalkanes of the formula (I) con-~e A 25 654 - 1 -tain at least two fluorine atoms, can be used advantageously as propellants.
Those. polyfluoroalkanes of the formula (I) are preferred which contain 3 to 7, particularly 4 to 6 fluorine atoms. , Furthermore, those polyfluoroalkanes of the formula (I) are preferred in which the C83 group repre-sents a CF3, CHFz or CHI group and the CYz group represents a CHZ, CFC?', CFi or C ( CFA ) H group .
For the use according to the invention, those individual compounds conforming to formula (I) in which X3, YZ and R are present in one of the combinations listed in Table l, are particularly preferred.
Le A 26 ,~54 _ Table 1 ~

z yz R

F3 Hz CH2F

F3 ~ ~ CHZF

xF2 FZ cHZF

F3 ~ ~

H3 Fz CH3 F3 Fz CFZ-CH3 F3 HCF3 ~3 F3 Hz CHZ-CHZ-CH3 F3 H2 -CH ( CIi3 ) -CH3 The methods for preparing the polyfluoroalkanes for use according to the invention are known (see, for example, Zh. Org. Rhim. 1980, 1401-1408 and 1982, 946 and 1168; Zh. Org. Rhim. 1988, 1558; J. Chem. Soc. Perk. 1, 1980, 2258; J. Chew. Soc. Perk. Traps. 2, 1983, 1713; J.
Chem. Soc. C 1969, 1739; Chem. Soe. 1949, 2860; Zh. Anal.
Khim. 1981 36 (6), 1125; J. Fluorine Chew. 1979, 325;
Izv. Akad. Nauk. SSSR, Ser. Rhim. ~Q, 2117 (in Russian); Rosz. Chew. 1974 (48), 1697 and J.A.C.S. ~7, 1195_(1945), ~, 3577 (1950) and J,~, 2343 (1954)).
The propellants for uae according to the ~.~~'~4 _ 3 invention.are particularly suitable for aerosols and production of plastic foams; the individual compounds of the formula (I), mixtures of compounds of the formula (I) and mixtures of compounds of the formula (I) with conven-tional propellants may be used for this purpose.
Individual compounds of the formula (I) or mixtures of compounds of the formula (I) are preferred.
Suitable aerosols are those employed for cosmetic and medicinal purposes, for example deodorant aerosols, anti-asthma sprays and liquid plaster sprays. Aerosols which employ the propellants for use according to the invention, are distinguished by the fact that the propel-lant is inert and the ozone layer of the earth's atmosphere is no longer negatively affected by the corresponding amount of propellants according to the invention, since they are chlorine-free.
The methods of producing plastic foams using propellants is generally known. In the production of closed-cell foams the propellants may also act as heat-insulating cellular gases. This is also true for the propellants for use according to the invention.
The propellants for use according to the inven-tion may be employed, for example, in the production of foams based on isocyanates, polystyrenes, polyvinyl chlorides and phenol-formaldehyde condensates. They are preferably used in the production of foams based on isocyanates, in particular in the production of poly urethane and/or polyisocyanurate foams; they are especially preferred in the production of rigid foams based on isocyanates.
he A 26 654 -The production of foams based on isocyanates is known per se and is described, for example, in German Offenlegungsschriften 1,694,142, 1,694,215 and l,?20,?68, as well as in Bunststoff-Handbuch [Plastics Handbook], volume VII, Polyurethane, edited by Vieweg and HtSchtlen, Carl Hanser Verlag, Munich 1966, and in the new edition of this tome, edited by G. Oertel, Carl Hanser Verlag, Munich, Vienna, 1983.
These foams are mainly those comprising urethane and/or isocyanurate and/or allophanate and/or uretdione and/or urea and/or carbodiimide groups.
The following can be employed for the production of foams based on isocyanates, using propellants accord-ing to the inventions a) As starting components aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyiso-cyanates, such as those described, for example, lay W. Siefken in Justus Liebigs Annalen der Che>zEi~e, 562, pp. ?5-136, for example those of the formula Q(NCO)n in which n denotes 2-4, preferably 2-3, and Q denotes an aliphatic hydrocarbon radical of 2-18, preferably 6-10 carbon atoms, a cycloaliphatic hydrocarbon radical of 4-15, preferably 5-10 carbon atoms, an aromatic hydrocarbon radical of 6-15, preferably 6-13 carbon atoms or an araliphatic _hydrocarbon radical of 8-15, preferably 8-13 carbon atoms, for example such polyisocyanates as described Le A 26 654 - 5 -in DE-OS 2,832,253, pp. 10-11. Particularly prefer-red are usually those polyisocyanates which are technically readily accessible, for example the 2,4-and 2,6-toluylene diisocyanate as well as any mixture of~these isomers ("TDI"); polyphenylpoly-methylenepolyisocyanates, such as those obtained by an aniline-formaldehyde condensation and subsequent treatment with phosgene ("crude 1~I"), and poly-isocyanates comprising carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups ("modified polyiso cyanates"), especially those modified polyiso cyanates which are derived from 2,4- and/or 2,6 toluylene diisocyanate and from 4,4'- and/or 2,4' diphenylmethane diisocyanate.
b) The starting components may further be compounds of a molecular weight usually of 400 to 10,000, con-taining at least two hydrogen atoms reactive toward isocyanates. These comprise, besides compounds containing amino, thio or carboxyl groups, preferab-ly compounds containing hydroxyl groups, in particular compounds containing 2 to 8 hydroxyl groups, especially those of a molecular weight of 1,000 to 6,000, preferably 2,000 to 6,000, for example polyethers and polyesters as well as poly-carbonates and polyester amides containing at least 2, usually 2 to 8, pr~ferably 2 to 6 hydroxyl groups; these compounds are known per se for the _preparation of homogeneous and cellular polyure-thanes and are disclosed, for example, in DE-OS
Le A 26 654 2,832,253, pp. 11-18.
c) When appropriate, compounds comprising at least two hydrogen atoms reactive toward isocyanates and of a molecular weight of 32 to 399 may be used as further starting components. Also in this case compounds containing hydroxyl groups and/or amino groups and/or thiol groups and/or carboxyl groups, pre-ferably compounds containing hydroxyl groups and/or amino groups, are understood to be those which are used as chain lengtheners or crosslinking agents.
These compounds usually have 2 to 8, preferably 2 to 4 hydrogen atoms reactive toward isocyanates.
Appropriate examples are disclosed in DE-OS
2,832,253, pp. 19-20.
d) One polyfluoroalkane or several polyfluoroalkanes of the formula (I) as propellant and insulating gas, if appropriate in admixture with conventional propel-lants and insulating gases.
- e) When appropriate, other auxiliary agents and addi tives may be used at the same time, such as - water and/or other highly volatile organic substances as propellants, - additional catalysts of the type known per se in amounts up to 10% by weight, based on the com ponent b), - surface-active additives, such as emulsifiers and foam stabilizers, - reaction retardants, for esample acidic substan - ces such as hydrochloric acid or organic acid halides, also cell regulators of the type known L~ A 26 654 -per se such as paraffins or fatty alcohols or dimethylpolysiloxanes as well as pigments or dyes and other flame retardants of the type known per se, for example tricresyl phosphate, also stabi-lizers against the effects of ageing and weathering, plasticizers and fungistats and bacteriostats as well as fillers such as barium sulphate, kieselguhr, carbon black or whiting.
Other examples of surface active additives, foam stabilizers, cell regulators, reaction retardants, stabilizers, flame retardants, plasticizers, dyes, fillers, fungistats, bacteriostats to be used at the same time if appropriate, as well as details concerning the use and action of these additives are described in Kunststoff-Handbuch [Plastics Handbook , volume VII, edited by Vieweg and Htichtlen, Carl Hanser Verlag, Munich 1966, for example on pages 103-113.
The isocyanate-based foams can be prepared in a manner known per se.
The preparation of polyurethane plastics may be prepared, for example, as followss the reactants are caused to react by the single-stage process known per se, the prepolymer process or the semiprepolymer process, frequent use being made of plant machinery, for example that disclosed in US 2,764,565. Details concerning the processing plant which are likewise relevant according to the invention, are described in lCunatatoff-Handbuch, volume VII, edited by Vieweg and HtSchtlen, Carl Hanser Verlag, Munich 1966, for example on pages 121 to 205.
.
Le A 26 654 _ g According to the invention it is also possible to produce cold-curing foams (cf. GB-PS 1,162,517, DE-OS
2, 153, 086) .
Foams may of course also be produced by block foaming or by the double conveyor belt process known per se.
The products obtainable according to the invention may be used, for example, as insulation panels for roof insulation.
In foam production, the propellants for use according to the invention may be employed, for example, in amounts of 1 to 30o by weight, preferably 2 to loo by weight, in each case based on the foam.
Compared with conventional foams of similar or virtually identical cell structure, foams produced by propellants for use according to the invention are distinguished by the fact that in their production, application and disposal they no longer negatively affect the ozone layer of the earth's atmosphere by the corresponding amount of the propellants according to the invention.
Polyfluoroalkanes of the formula (I) may be further employed as degreasing and cleansing agents, for example in the electrical industry. The same polyfluoroalkanes are preferred for this purpose as those referred to above as being preferred.
Here, too, the individual compounds of the formula (I), mixtures of compounds of the formula (I) and mixtures of compounds of the formula (I) with conventional degreasing and cleansing agents may be employed.

'_ Example 1 100 g of a polyether with a hydroxyl value of 380, which has resulted from the addition of propylene oxide to a solution of saccharose, propylene glycol and water, 2 g of a :~Filoxane polyether copolymer as foam stabilizer, 3.8 g of water and 3 g of dimethylcyclohexylamine were mixed.
100 g of this mixture were thoroughly mixed with 15 g of 1,1,1,3,3,3-hexafluoro-2-methylpropane as propellant, using a laboratory stirrer'.
This mixture was foamed with 152 g of crude 4,4 ~-diisocyanatodiphenylmethane. A rigid polyurethane foam was obtained. Foaming and physical datas Induction time (s) s 10 Setting time (s) s 42 Free density (kg/m') s 24 Cell structure s fine Example 2 100 g of a polyether with a hydroxyl value of 380 which results from the addition of propylene oxide to a solution of saccharose, propylene glycol and water, 2 g of a siloxane polyether copolymer as foam stabilizer, 3.8 g of water and 3 - g of dimethylcyclohexylamine were mixed.
Le A 26 654 - 10 -~-" , 100 g of this mixture were thoroughly mixed with 15 g of 1,1,1,3,3,3-hexafluoropropane as propellant, using a laboratory stirrer.
This mixture was foamed with 152 g of crude 4,4' diisocyanatodiphenylmethane. A rigid polyurethane foam was obtained. Foam and physical datas Induction time (s) : 10 Setting time (s) : 40 Free density (kglm3) : 22 Cell structure : fine.
I~e A 26" 654 - 11 -'. CA 02303709 2000-04-11 Example 3 100 g of a polyether with a hydroxyl value of 380 which - results~from the addition of propylene oxide to a solution of saccharose, propylene glycol and water, 2 g of a siloxane polyether copolymer as foam stabilizer, 3.8 g of water and 3 g of dimethylcyclohexylamine were mixed.
100 g of this mixture were thoroughly mixed with 15 g of 2,2,4,4-tetrafluorobutane as propellant, using a laboratory stirrer.
This mixture was foamed with 152 g of crude 4,4'~
diisocyanatodiphenylmethane. A rigid polyurethane foam was obtained. Foaming and physical dates Induction time (s) s 10 Setting time (s) : 39 Free density (kg/m~) : 21 dell structure s fine.
Example 4 60 g of a polyether with a hydroxyl value of 950 which resulted from the addition of propylene oxide to trimethylpropane, 40 g of a polyether with a hydroxyl value of 56 which Le A 26 654 - 12 -resulted from the addition of propylene oxide to trimethylpropane, 0.5 g of water and 2 g of a siloxane polyether copolymer as foam stabi-lizer were mixed.
100 g of this mixture was thoroughly mixed with g of 1,1,1,3,3,3-hezafluoro-2-methylpropane as propellant, using a laboratory stirrer.
This mixture was foamed with 164 g of crude 4,4'-10 diisocyanatodiphenylmethane. A rigid solid polyurethane plastic was obtained. Foaming and physical data:
Induction time (8) _ ~5 Setting time (s) s 120 Free density (kg/m3) s 75 Total density compacted (kg/m'j : 350 Cell structure : fine.
Example 5 - 60 g of a polyether with a hydroxyl value of 950 which resulted from the addition of propylene oxide to trimethylpropane, 40 g of a polyether with a hydroxyl value of 56, which resulted from the addition of propylene oxide to trimethylolpropane, 0.5 g of water and 2 g of a siloxane polyother copolymer as foam stabi-lizer were mixed.
100 g of this mixture were thoroughly mixed with Ire A 26 654 - 13 --. CA 02303709 2000-04-11 g of the 1,1,1,3,3,3-hexafluoropropane according to the invention as propellant, using a laboratory stirrer.
This mixture was foamed with 164 g of crude 4,4'-5 diisocyanatodiphenylmethane. A rigid solid polyurethane plastic was obtained. Foaming and physical data:
Induction time (s) s 88 Setting time (s) s 136 Free density (kg/m3) s 70 10 Total density compacted (kg/m') s 350 Cell structure s fine.
Fxample 6 60 g of a polyether with a hydroxyl value of 950 which resulted from the addition of propylene oxide to trimethylolpropane, 40 g of a polyether with a hydroxyl value of 56 which resulted from the addition of propylene oxide to trimethylolpropane, 0.5 g of water and 2 g of a siloxane polyether copolymer as foam stabi-lizer were mixed.
100 g of this mixture were thoroughly mixed with 10 g of 2,2,4,4-tetrafluorobutane as propellant, using a laboratory stirrer.
This mi~cture was foamed with 164 g of crude 4,4'-dii:ocyanatodiphenylmethane. A rigid solid polyurethane plastic was obtained. Foaming and physical data:
I~e A 26 654 - 14 -'- CA 02303709 2000-04-11 Induction time (s) . 83 Setting time (s) s 138 Free density (kg/m') s 68 Total density compacted (kg/m') s 350 Cell structure s fine.
Example 7 91 g of a polyether with a hydroxyl value of 56 which resulted from the addition of propylene oxide to trimethylolpropane, 9 g of monoethylene glycol and 0.1 g of water were mixed.
100 g of this mixture were thoroughly mixed with g of 1,1,1,3,3,3-hexafluoro-2-methylpropane as propellant, using a laboratory stirrer.
This mixture was foamed with 56 g of crude 4,4~-15 diisocyanatodiphenylmethane. A tough and resilient polyurethane foam was obtained. Foaming and physical data:
Induction time (s) s 33 Setting time (s) s 112 Free density (kg/m') s 131 Total density compacted (kg/m3) s 350 Cell structure s fine.
Example 8 91 g of a polyether with a hydroxyl value of 56, which resulted from the addition of propylene oxide to trimethylolpropane, - 9 _ g of monoethylene glycol and 0.1 g of water were mixed.
he A 26 654 - 15 -100 g of this mixture were thoroughly mixed with 15 g of, 1,1,1,3,3,3-hexafluoropropane as propellant, using a laboratory stirrer.
This mixture was foamed with 56 g of crude 4,4'-diisocyanatodiphenylmethane. A tough and resilient polyurethane foam was obtained. Foaming and physical.
data:
Induction time (s) s 36 Setting time (s) s 108 Free density (kg/m3) s 121 Cell structure s fine.
Example 9 91 g of a polyether with a hydroxyl value of 56, which resulted from the addition of propylene oxide to trimethylolpropane, 9 g of monoethylene glycol and 0.1 g of water were mixed.
100 g of this mixture were thoroughly mixed with 15 g of 2,2,4,4-tetrafluorobutane as propellant, using a laboratory stirrer.
This mixture was foamed with 56 g of crude 4,4'-diisocyanatodiphenylmethane. A tough and resilient polyurethane foam was obtained. Foaming and physical data: .
Induction time (a) s 38 Setting time (s) : 108 Free density (kg/m~) s 117 Cell structure : fine Le A 26 654 - 16 -Example 10 100 g of a polyether with a hydroxyl value of 56, which resulted from the addition of propylene oxide~to trimethylolpropane, 3 g of water, 1 g of a siloxane polyether copolymer as foam stabilizer, 0.05 g of dibutyltin dilaurate were mixed.
100 g of this mixture were thoroughly mixed with 10 g of 1,1,1,3,3,3-hexafluoro-2-methylpropane as propellant, using a laboratory stirrer.
This mixture was foamed with 41 g of toluylene diisocyanate. A flexible polyurethane foam was obtained.
Foaming and physical data:
Induction time (s) s 8 Setting time (s) z 105 Free density (kg/m3) s 28 -Cell structure z fine.
Example 11 100 g of a polyether with a hydroxyl value of 56, which resulted from the addition of propylene oxide to trimethylolpropane, 3 g of water, 1 g of a ailoxane polyether copolymer as foam stabilizer, 0.05 g of d3butyltin dilaurate werre mixed.
I~e A 26 654 - 17 -100 g of this mixture were thoroughly mixed with g of 1,1,1,3,3,3-hexafluoropropane as propellant, using a laboratory stirrer.
This mixture was foamed with 41 g of toluylene 5 diisocyanate. A flexible polyurethane foam was obtained.
Foaming and physical data:
Induction time (s) s 8 Setting time (s) s 103 Free density (kg/m') s 26 10 Cell structure s fine.
,Lxample 12 100 g of a polyether with a hydroxyl value of 56, which resulted from the addition of propylene oxide to trimethylolpropane, 3 g of water, 1 g of a siloxane polyether copolymer as foam stabilizer, 0.05 g of dibutyltin dilaurate were mixed.
100 g of this mixture were thoroughly mixed with 10 g of 2,2,4,4-tetrafluorobutane as propellant, using a laboratory stirrer.
This mixture was foamed with 41 g of toluylene diisocyanate. A flexible polyurethane foam was obtained.
Foaming and physical data:
Induction time (8) s 8 Setting time (s) s 108 Free den8ity (kg/m') s 25 Cell structure s fine.
?~e A 2b 654 ~ 18 -

Claims (2)

CLAIMS:

1. A method for cleaning a surface which comprises treating said surface with at least one polyfluoroalkane of the formula:

wherein each of the X radicals independently stand for hydrogen or fluorine, and each of the Y radicals independently stand for hydrogen, fluorine or CF3, and R stands for CH2-F, CHF2, CH3, CF3, CF2-CH3, CF2CH2F, CH2-CH3, CH2-CH2-CH3 or -CH(CH3)-CH3, wherein the polyfluoroalkanes contain at least two fluorine atoms or a mixture of at least one of said polyfluoroalkanes with conventional propellants or degreasing and cleansing agents.

2. A method for cleaning a surface useful in the electrical industry which comprises treating said surface with at least one polyfluoroalkane of the formula:

wherein each of the X radicals independently stand for hydrogen or fluorine, and each of the Y radicals independently stand for hydrogen, fluorine or CF3, and R stands for CH2-F, CHF2, CH3, CF3, CF2-CH3, CF2CH2F, CH2-CH3, CH2-CH2-CH3 or -CH(CH3)-CH3 wherein the polyfluoroalkanes contain at least two fluorine atoms or a mixture of at least one of said polyfluoroalkanes with conventional propellants or degreasing and cleansing agents.