CA2242695A1 - Production of flexible polyurethane foams - Google Patents
Production of flexible polyurethane foams Download PDFInfo
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- CA2242695A1 CA2242695A1 CA002242695A CA2242695A CA2242695A1 CA 2242695 A1 CA2242695 A1 CA 2242695A1 CA 002242695 A CA002242695 A CA 002242695A CA 2242695 A CA2242695 A CA 2242695A CA 2242695 A1 CA2242695 A1 CA 2242695A1
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- compounds
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- polyether
- polyisocyanates
- polyether chains
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
- C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0008—Foam properties flexible
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0041—Foam properties having specified density
- C08G2110/005—< 50kg/m3
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0083—Foam properties prepared using water as the sole blowing agent
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2205/00—Foams characterised by their properties
- C08J2205/06—Flexible foams
Abstract
Flexible polyurethane foams are produced by reacting a) polyisocyanates with b) compounds containing at least two active hydrogen atoms in the presence of c) blowing agents d) catalysts and also e) auxiliaries and/or additives, wherein prepolymers containing isocyanate and urethane groups and derived from diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates and polyether polyols are used as polyisocyanates a), polyester polyols are used as compounds b) containing at least two active hydrogen atoms, and compounds comprising silicon atoms and polyether chains are used as auxiliaries and/or additives e).
Description
BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Production of flexible polyurethane foams 5 The present invention relates to a process for producing flexible polyurethane foams based on diphenylmethane diisocyanate and polyester polyols.
Flexible polyurethane foams have been known for a long time and 10 are widely described in the literature. They are customarily produced by reacting polyisocyanates with compounds which have two or more active hydrogen atoms in the molecule.
Tolylene diisocyanate (TDI) is usually used as polyisocyanate for 15 producing flexible polyurethane foams, but diphenylmethane diisocyanate (MDI) is frequently also used. As compounds containing at least two active hydrogen atoms for producing flexible polyurethane foams, use is usually made of bifunctional and/or trifunctional polyetherols and/or polyesterols having 20 hydroxyl numbers in the range from about 20 to 100 mg KOH/g.
In certain fields of application, for example for producing foam composites with textile materials by the flame bonding method, it is advantageous to use polyesterols as polyols. The polyurethanes 25 thus produced have increased tack when molten, leading to better adhesion between polyurethane and the textile material.
When using MDI as isocyanate component, use of polyesterols 30 frequently results in processing problems. Since MDI is difficult to process as a solid, it is usually liquified by chemical reaction. A frequently used method of liquifying MDI is the reaction with polyols to give isocyanate-terminated prepolymers.
Such a prepolymer is described in DE-A-44 11 781. This is a 35 reaction product of a mixture of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates (crude MDI) with at least one trifunctional polyoxypropylene polyol. This prepolymer is reacted with a polyol component to give flexible polyurethane foams. Although DE-A-44 11 781 mentions the use of polyester 40 polyols as polyol component, only polyether polyols are described as polyol component in the examples.
It has been found that the use of polyesterols as polyol component in the reaction with prepolymers containing isocyanate 45 groups, which have been prepared by reacting MDI and in particular crude MDI with polyetherols, leads to processing problems and lower quality foams, if foams are formed at all. The CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 foams were usually closed-celled, shrank to a great extent and complete collaPse of the reaction product immediately after foaming frequently occurred.
5 It is an object of the present invention to produce flexible polyurethane foams based on polyesterols and MDI which are open-celled and dimensionally stable, have good mechanical properties and can be coated with textile materials by flame bonding.
We have found that this object is achieved by a process for producing flexible polyurethane foams by reacting polyisocyanates with polyols, wherein prepolymers from the reaction of mixtures 15 of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates with polyetherols are used as polyisocyanates, polyester polyols are used as polyols and the reaction is carried out in the presence of a compound comprising silicon atoms and polyether chains.
The present invention accordingly provides a process for producing flexible polyurethane foams by reacting a) polyisocyanates with b) compounds containing at least two active hydrogen atoms in the presence of c) blowing agents d) catalysts and also e) auxiliaries and/or additives, wherein prepolymers containing isocyanate and urethane groups and derived from the reaction of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates with polyether polyols 35 are used as polyisocyanates a), polyester polyols are used as compounds b) containing at least two active hydrogen atoms, and compounds comprising silicon atoms and polyether chains are used as auxiliaries and/or additives e).
40 The prepolymers containing isocyanate groups and obtained from the reaction of MDI and its higher homologues with polyether polyols preferably have an NCO content of from 22 to 30 % by weight and are liquid at room temperature.
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Isocyanates used as starting materials for preparing the prepolymers containing isocyanate groups are preferably mixtures of diphenylmethane diisocyanate isomers and polyphenylpolymethylene polyisocyanates, usually known as crude 5 MDI. In particular, use is made of mixtures which comprise al) from 45 to 65 % by weight of diphenylmethane 4,4'-diisocyanate, 10 a2) from 10 to 50% by weight of diphenylmethane 2,4'-diisocyanate, a3) from 0 to 1 % by weight of diphenylmethane 2,2'-diisocyanate and a4) from 45 to 1 % by weight of at least trifunctional polyphenylpolymethylene polyisocyanates.
Such products and their preparation are described in DE-A-44 11 781.
As polyether polyols, preference lS given to using trifunctlonal polyether polyols, in particular pure polyoxypropylene polyols.
The hydroxyl number of the polyether polyols is from 20 to 60 mg KOH/g.
The polyester polyols used according to the present invention as component b) are prepared by reacting at least bifunctional alcohols with at least bifunctional carboxylic acids.
30 The polyester polyols used according to the present invention are preferably bifunctional, possibly slightly branched, and have a hydroxyl number in the range from 10 to 100 mg KOH/g.
Suitable polyester polyols can be prepared, for example, from 35 organic dicarboxylic acids having from 2 to 12 carbon atoms, preferably aliphatic dicarboxylic acids having from 4 to 6 carbon atoms, and polyhydric alcohols, preferably alkanediols, having from 2 to 12 carbon atoms, preferably from 2 to 6 carbon atoms, and/or dialkylene glycols. Examples of suitable dicarboxylic 40 acids are: succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acids can be used either individually or in admixture with one another. In place of the 45 free dicarboxylic acids, it is also possible to use the corresponding dicarboxylic acid derivatives such as dicarboxylic esters of alcohols having from 1 to 4 carbon atoms or CA 0224269~ 1998-08-14 - BASF Aktiengesellschaft 970269 O.Z. 0050/48225 dicarboxylic anhydrides. Preference is given to using dicarboxylic acid mixtures of succinic, glutaric and adipic acids in weight ratios of, for example, 20 - 35: 35 - 50: 20 - 32, and in particular adipic acid. Examples of dihydric and 5 polyhydric alcohols, in particular alkanediols, dialkylene glycols and triols are:
Ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, l,4-butanediol, 1,5-pentanediol, 10 1,6-hexanediol, l,10-decanediol, glycerol and trimethylolpropane.
Preference is given to using ethanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or mixtures of at least two of the alkanediols mentioned, in particular mixtures of 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol. It is also 15 possible to use polyester polyols derived from lactones, eg.
~-caprolactone, or hydroxycarboxylic acids, eg. cl)-hydroxycaproic acid.
20 To prepare the polyester polyols, the organic, eg. aromatic and preferably aliphatic polycarboxylic acids and/or derivatives and polyhydric alcohols and/or dialkylene glycols can be polycondensed in the absence of catalysts or preferably in the presence of esterification catalysts, advantageously in an atmosphere of inert gases, eg. nitrogen, helium, argon, etc., in the melt at from 150 to 250OC, preferably from 180 to 220~C, under atmospheric pressure or reduced pressure to the desired acid number which is advantageously less than 10, preferably less than 2. According to a preferred embodiment, the esterification 30 mixture is polycondensed at the abovementioned temperatures to an acid number of from 80 to 30, preferably from 40 to 30, under atmospheric pressure and subsequently under a pressure of less than 500 mbar, preferably from 50 to 150 mbar. Suitable esterification catalysts are, for example, iron, cadmium, cobalt, 35 lead, zinc, antimony, magnesium, titananium and tin catalysts in the form of metals, metal oxides or metal salts. However, the polycondensation can also be carried out in the liquid phase in the presence of diluents and/or entrainers such as benzene, toluene, xylene or chlorobenzene to azeotropically distil off the 40 water of condensation. To prepare low-fogging polyester polyols, the polyester polyols obtained can be subjected to at least one additional distillation under reduced pressure, eg. in a thin-film and/or falling-stream evaporator.
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 To prepare the polyester polyols, the organic polycarboxylic acids and/or derivatives and polyhydric alcohols are advantageously polycondensed in a molar ratio of 1:1 - 1.8, preferably 1:1.05 - 1.2.
~he polyester polyols obtained have a functionality of preferably from 2 to 4, in particular from 2 to 3, and a molecular weight of from 1800 to 3600, preferably from 2200 to 3200.
As regards the other starting materlals for the process of the present invention, the following details may be provided.
As blowing agent c) for producing the flexible PU foams, use is 15 made, in particular, of water which reacts with isocyanate groups to form carbon dioxide. The amounts of water which are advantageously used are from 0.1 to 8 parts by weight, preferably from 2.5 to 6.0 parts by weight and in particular from 3.3 to 4.3 parts by weight, based on 100 parts by weight of the 20 polyhydroxyl compounds (b).
Also suitable as blowing agents are liquids which are inert toward the liquid polyisocyanate mixture (a) which has been modified with urethane groups and have boiling points below 80~C, 25 preferably below 50~C, in particular from -50~C to 30~C, at atmospheric pressure so that they vaporize under the action of the exothermic polyaddition reaction, and also mixtures of such physically acting blowing agents and water. Examples of such liquids which are preferably used are alkanes such as heptane, 30 hexane, n- and iso-pentane, preferably industrial mixtures of n-and iso-pentanes, n- and iso-butane and propane, cycloalkanes such as cyclopentane and/or cyclohexane, ethers such as furan, dimethyl ether and diethyl ether, ketones, such as acetone and methyl ethyl ketone, alkyl carboxylates such as methyl formate, 35 dimethyl oxalate and ethyl acetate and halogenated hydrocarbons such as methylene chloride, dichloromonofluoromethane, difluoromethane, trifluoromethane, difluoroethane, tetrafluoroethane, chlorodifluoroethanes, 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane 40 and heptafluoropropane. Mixtures of these low-boiling liquids with one another and/or with other substituted or unsubstituted hydrocarbons can also be used. Further suitable blowing agents are organic carboxylic acids such as formic acid, acetic acid, oxalic acid, ricinoleic acid and other carboxyl-containing 45 compounds.
CA 0224269~ 1998-08-14 BASF AktiengesellSchaft 970269 O.Z. 0050/48225 Blowing agents which are preferably used are chlorodifluoromethane, chlorodifluoroethanes, dichlorofluoroethanes, pentane mixtures, cyclopentane, cyclohexane and in particular water and also mixtures of at least 5 two of these blowing agents, eg. mixtures of water and cyclopentane and/or cyclohexane, mixtures of chlorodifluoromethane and l-chloro-2,2-difluoroethane and, if desired, water. Blowing agents which are not used are chlorofluorocarbons which damage the ozone layer.
The necessary amount of physically acting blowing agents can be determined experimentally in a simple manner as a function of the desired foam density and the amount of any water used and is from about 0 to 25 parts by weight, preferably from 0 to 15 parts by 15 weight, per 100 parts by weight of the polyhydroxyl compounds (b). It may be advantageous to mix the polyisocyanate mixtures (a) containing bound urethane groups with the inert, physically acting blowing agent and thus lower their viscosity.
Catalysts (d) used for producing the flexible foams according to the present invention are preferably compounds which strongly accelerate the reaction of the hydroxyl-containing compounds of the component (b) with the liquid MDI-based polyisocyanate 25 mixtures (a) containing bound urethane groups. Suitable catalysts are organic metal compounds, preferably organic tin compounds such as tin(II) salts of organic carboxylic acids, eg. tin(II) acetate, tin(II) octoate, tin(II) ethylhexanoate and tin(II) laurate, and dialkyltin(IV) salts of organic carboxylic acids, 30 eg. dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate and dioctyltin diacetate, and strongly basic amines, for example amidines such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tertiary amines such as triethylamine, tributylamine, dimethylbenzylamine, N-ethylmorpholine, 35 N-cyclohexylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylbutanediamine, N,N,N',N'-tetramethylhexane-1,6-diamine, bis(4-dimethylaminocyclohexyl)methane-pentamethyldiethylenetriamine, bis(dimethylaminoethyl) ether, 40 bis(dimethylaminopropyl)urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-aza-bicyclo[3.3.0]octane and preferably 1,4-diazabicyclo[2.2.2]octane and alkanolamine compounds such as triethanolamine, triisopropanolamine, N-methyldiethanolamine and N-ethyldiethanolamine and dimethylethanolamine.
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Further suitable catalysts are:
tris(dialkylaminoalkyl)-s-hexahydrotriazines, in particular tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine, tetraalkylammonium hydroxides, such as tetramethylammonium 5 hydroxide, alkali metal hydroxides, such as sodium hydroxide and alkali metal alkoxides such as sodium methoxide and potassium isopropoxide and also alkali metal salts of long-chain fatty acids having from 10 to 20 carbon atoms and possibly lateral OH
groups and combinations of the organic metal compounds and 10 strongly basic amines. Also suitable as catalysts are derivatives of morpholine such as N-methylmorpholine or N-ethylmorpholine.
Preference is given to using from 0.001 to 5 % by weight, in particular from 0.05 to 2 % by weight, of catalyst or catalyst combination, based on the weight of the polyhydroxyl compound 15 (b).
The reaction mixture for producing the flexible PU foams further comprises additives (e). According to the present invention, the reaction mixture comprises, as indicated above, compounds 20 comprising silicon atoms and polyether chains. These are preferably used in an amount of from 0.5 to 5 % by weight, based on the component b). These compounds are silicone-polyether copolymers. The products have an average molecular weight (Mw) of about 8000, with the molecular weight distribution being 25 relatively broad. The siloxane chain has an average length of about 40 (CH3)2SiO units and has an average of 5 polyether chains linked to it. The polyether chains preferably comprise ethylene oxide and propylene oxide in a ratio of 1:1 and have a hydroxyl group at the end. The molecular weight of the polyether chains is 30 about 1500-Such products are commercially available and are sold, forexample, by Goldschmidt AG under the name Tegostab~.
Further additives e) are, for example, surface-active substances, foam stabilizers, cell regulators, fillers, dyes, pigments, flame retardants, hydrolysis inhibitors, fungistatic and bacteriostatic substances.
Suitable surface-active substances are, for example, compounds which serve to aid the homogenization of the starting materials and may also be suitable for regulating the cell structure.
Examples which may be mentioned are emulsifiers such as the 45 sodium salts of castor oil sulfates or fatty acids and also amine salts of fatty acids, eg. diethylamine oleate, diethanolamine stearate, diethanolamine ricinoleate, salts of sulfonic acids, CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 eg. alkali metal or ammonium salts of dodecylbenzene- or dinaphthylmethanedisulfonic acid and ricinoleic acidi foam stabilizers such as siloxane-oxyalkylene copolymers and other organopolysiloxanes, ethoxylated alkylphenols, ethoxylated fatty 5 alcohols, paraffin oils, castor oil or ricinoleic esters, Turkey red oil and peanut oil and cell regulators such as paraffins, fatty alcohols and dimethylpolysiloxanes. Oligomeric polyacrylates having polyoxyalkylene and fluoroalkane radicals as side groups are also suitable for improving the emulsifying 10 action, the cell structure and/or stabilizing the foam. The surface-active substances are usually employed in amounts of from 0.01 to 5 parts by weight, based on 100 parts by weight of the polyhydroxyl compound (b).
15 For the purposes of the present invention, fillers, in particular reinforcing fillers, are the customary organic and inorganic fillers, reinforcing materials and weighting agents known per se.
Specific examples are: inorganic fillers such as siliceous minerals, for example sheet silicates such as antigorite, 20 serpentine, hornblends, amphiboles, chrysotile, zeolites, talc;
metal oxides, such as kaolin, aluminum oxides, titanium oxides and iron oxides, meta salts such as chalk, barite, aluminum silicates and inorganic pigments such as cadmium sulfide, zinc sulfide and also glass particles. Examples of organic fillers 25 are: carbon black, melamine, rosin, cyclopentadienyl resins and graft polymers.
The inorganic and organic fillers can be used individually or as 30 mixtures and are advantageously incorporated into the reaction mixture in amounts of from 0.5 to 50 % by weight, preferably from 1 to 40 % by weight, based on the weight of the components (a) and (b).
35 Suitable flame retardants are, for example, tricresyl phosphate, tris(2-chloroethyl) phosphate, tris(2-chloropropyl) phosphate, tris(1,3-dichloropropyl) phosphate, tris(2,3-dibromopropyl) phosphate and tetrakis(2-chloroethyl)ethylene diphosphate.
40 Apart from the halogen-substituted phosphates mentioned above, it is also possible to use inorganic flame retardants such as red phosphorus, hydrated aluminum oxide, antimony trioxide, arsenic oxide, ammonium sulfate, ammonium polyphosphate, expandable graphite and calcium sulfate or cyanuric acid derivatives such as 45 melamine or mixtures of at least two flame retardants such as ammonium polyphosphates and melamine and/or expandable graphite and, if desired, starch for making the (molded) flexible PU foams CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 produced according to the present invention flame resistant. In general, it has been found to be advantageous to use from 5 to 50 parts by weight, preferably from 5 to 25 parts by weight, of said flame retardants or mixtures per 100 parts by weight of the 5 components (a) and (b).
Further details regarding the abovementioned other customary auxiliaries and additives may be found in the specialist literature, for example the monograph by J.H. Saunders and K.C.
10 Frisch UHigh Polymersn, Volume XVI, Polyurethanes, Parts 1 and 2, Interscience Publishers 1962 and 1964, or the Kunststoff-Handbuch, Polyurethane, Volume VII, Carl-Hanser-Verlag, Munich, Vienna, 1st, 2nd and 3rd editions, 1966, 1983 and 1993.
To produce the flexible PU foams, the liquid polyisocyanate mixtures (a) containing urethane groups in bound form and compounds (b) containing at least two active hydrogen atoms can 20 be reacted in the presence of blowing agents (c), catalysts (d) and, if desired, additives (e) at, for example, from 10 to 100~C, preferably from 18 to 80~C, in such ratios that advantageously from 0.5 to 2, preferably from 0.8 to 1.3 and in particular about one, reactive hydrogen atom(s) bound to the starting component 25 (b) is/are present per NCO group and, if water is used as blowing agent, the molar ratio of equivalents of water to equivalents of NCO groups is advantageously 0.5 - 5:1, preferably 0.7 - 0.95:1 and in particular 0.75 - 0.85:1.
30 The flexible PU foams are advantageously produced in a multicomponent foaming process, where the starting components (b), (c), (d) and (e) as separate streams are combined in the mixing head of a high-pressure or low-pressure machine and the polyisocyanate component used is the polyisocyanate mixture 35 containing bound urethane groups, if desired in admixture with (c). The reaction mixture can be foamed in open or closed molds;
it is also suitable for the production of molded foams.
To produce the flexible PU foams, the reaction mixture is 40 advantageously introduced at from 18 to 80~C, preferably from 30 to 65~C, into an advantageously metallic, heatable mold. The mold temperature is usually from 20 to 90~C, preferably from 35 to 70~C. The reaction mixture is allowed to cure in the closed mold with compaction, eg. at degrees of compaction of from 1.1 to 8, 45 preferably from 2 to 6 and in particular from 2.2 to 4.
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 The flexible PU foams usually have free-foamed densities of, for example, from 20 to 60 g/l, preferably from 40 to 55 g/l and in particular from 45 to 52 g/l. The flexible PU foam moldings produced from such foam formulations can have an overall density 5 of from 36 to 55 g/l, preferably from 45 to 50 g/l, depending on the degree of compaction employed.
The flexible PU foams produced by the process of the present invention are suitable, for example, as seat cushions for 10 upholstered furniture, the molded flexible PU foams are suitable as upholstery elements, armrests, headrests, sun visors and safety coverings in vehicle interiors, preferably in motor vehicles and aircraft.
The flexible foams can be firmly bonded to textile materlals by the flame bonding process.
The invention is illustrated by the following examples:
Examples 1 to 7 The components indicated in Table 1 were combined to form a polyol component and were foamed together with a prepolymer from 25 the reaction of 37.4 parts by weight of diphenylmethane 4,4l-diisocyanate, 37.4 parts by weight of diphenylmethane 2,41-diisocyanate, 12.4 parts by weight of a mixture of diphenylmethane isomers and polyphenylpolymethylene polyisocyanates (crude MDI) and 12.9 parts by weight of a 30 polyoxypropylene polyol having a hydroxyl number of 42 mg KOH/g and an NCO content of 28.5 % by weight with adherence to the indices indicated in Table 1 by means of a Cannon-Vikinq low-pressure foaming machine.
The foams obtained had the properties shown in Table 2.
It can be seen that the elongation and tensile strength of the foams increase with an increasing amount of stabilizer without 40 the other properties being impaired.
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BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Examples 8 to 12 The procedure of Examples 1 to 7 was repeatedi the precise ratios of the starting materials are indicated ln Table 4 and the 5 properties of the foams are shown in Table 5.
Table 4 10 Example 8 9 10 11 12 Polyol 1 100.00100.00 100.00 100.00 100.00 Lupragen~ N 2010.620.62 0.62 0.62 0.62 Lupragen~ N 2060.180.18 0.18 0.18 0.18 15 Stabilizer 11.50 1.50 2.00 2.00 2.00 Water 4.50 4.50 4.50 4.50 4.50 Index 100 100 100 90 80 Polyol:Isocyanatel)87.4 87.5 87.0 78.3 69.6 ) Mixing ratio = 100 parts by weight of polyol: x parts by weight of isocyanate as indicated in the table.
Table 5 Example 8 9 10 11 12 Density [kg/m3]31.130.5 30.3 31.4 34.1 30 Compressive 2.4 2.7 2.5 2.1 2.0 strength 40%
[kPa] DIN 53 577 Compressive set13.713.9 10.8 13.7 11.5 [%] *
35 Tensile strength 98 110 101 103 105 [kPa]
Elongation [%]141 152 156 181 200 40 Indentation hard- 111 128 119 99 91 ness B [N] 40 %
Elasticity [%]15 17 15 13 15 * 50 % compression for 22 hours at 70~C
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Examples 13 to 17 The procedure of Examples 1 to 7 was repeated; the precise ratios of the starting materials are indicated in Table 6 and the 5 properties of the foams are shown in Table 7.
Table 6 Example 13 14 15 16 17 10 Polyol 1 100.00 100.00 100.00100.00100.00 Lupragen~ N 201 0.74 0.740.74 0.74 0.74 Lupragen~ N 206 0.06 0.060.06 0.06 0.06 Stabilizer 1.50 1.50 2.002.00 2.00 15 Water 5.00 5-00 5-Index 100 100 90 80 110 Polyol:Isocyanatl~95.4 94.4 85 75.6 104 20 1) Mixing ratio = 100 parts by weight of polyol: x parts by weight of isocyanate as indicated in the table.
Table 7:
Example 13 14 15 16 17 Density [kg/m3] 27.9 26.2 27.4 26.5 32.2 Compressive 3.0 2.9 2.8 2.1 3.5 30 strength 40%
[kPa] DIN 53 577 Compressive set 18.6 31.2 26.4 38.4 11.2 [%] *
Tensile strength 108 102 120 102 103 35 [kPa]
Elongation [%]131 151 191 242 104 Indentation hard- 141 119 130 97 170 40 ness B [N] 40 %
Elasticity [%]19 22 19 19 22 45 * 50 % compression for 22 hours at 70~C
CA 0224269~ 1998-08-14 -BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Description of the products used Lupragen~ N 201: 33 % strength solution of diazabicyclooctane in dipropylene glycol Tegostab~ N 8701: Stabilizer from Goldschmidt, Essen Lupragen~ N 206: Bis(N,N-dimethylaminoethyl) ether, 70 %
solution in dipropylene glycol Polyol 1 Polyesterol based on adipic acid, diethylene glycol and trimethylolpropane having an OH
number of 61 mg KOH/g;
Stabilizer 1 Silicone-polyether copolymer, mean molecular weight Mw 8000, molecular weight of the polyether chain about 2500, ratio of ethylene to propylene in the polymer chain about 1:1 CA 0224269~ 1998-08-14
Flexible polyurethane foams have been known for a long time and 10 are widely described in the literature. They are customarily produced by reacting polyisocyanates with compounds which have two or more active hydrogen atoms in the molecule.
Tolylene diisocyanate (TDI) is usually used as polyisocyanate for 15 producing flexible polyurethane foams, but diphenylmethane diisocyanate (MDI) is frequently also used. As compounds containing at least two active hydrogen atoms for producing flexible polyurethane foams, use is usually made of bifunctional and/or trifunctional polyetherols and/or polyesterols having 20 hydroxyl numbers in the range from about 20 to 100 mg KOH/g.
In certain fields of application, for example for producing foam composites with textile materials by the flame bonding method, it is advantageous to use polyesterols as polyols. The polyurethanes 25 thus produced have increased tack when molten, leading to better adhesion between polyurethane and the textile material.
When using MDI as isocyanate component, use of polyesterols 30 frequently results in processing problems. Since MDI is difficult to process as a solid, it is usually liquified by chemical reaction. A frequently used method of liquifying MDI is the reaction with polyols to give isocyanate-terminated prepolymers.
Such a prepolymer is described in DE-A-44 11 781. This is a 35 reaction product of a mixture of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates (crude MDI) with at least one trifunctional polyoxypropylene polyol. This prepolymer is reacted with a polyol component to give flexible polyurethane foams. Although DE-A-44 11 781 mentions the use of polyester 40 polyols as polyol component, only polyether polyols are described as polyol component in the examples.
It has been found that the use of polyesterols as polyol component in the reaction with prepolymers containing isocyanate 45 groups, which have been prepared by reacting MDI and in particular crude MDI with polyetherols, leads to processing problems and lower quality foams, if foams are formed at all. The CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 foams were usually closed-celled, shrank to a great extent and complete collaPse of the reaction product immediately after foaming frequently occurred.
5 It is an object of the present invention to produce flexible polyurethane foams based on polyesterols and MDI which are open-celled and dimensionally stable, have good mechanical properties and can be coated with textile materials by flame bonding.
We have found that this object is achieved by a process for producing flexible polyurethane foams by reacting polyisocyanates with polyols, wherein prepolymers from the reaction of mixtures 15 of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates with polyetherols are used as polyisocyanates, polyester polyols are used as polyols and the reaction is carried out in the presence of a compound comprising silicon atoms and polyether chains.
The present invention accordingly provides a process for producing flexible polyurethane foams by reacting a) polyisocyanates with b) compounds containing at least two active hydrogen atoms in the presence of c) blowing agents d) catalysts and also e) auxiliaries and/or additives, wherein prepolymers containing isocyanate and urethane groups and derived from the reaction of diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates with polyether polyols 35 are used as polyisocyanates a), polyester polyols are used as compounds b) containing at least two active hydrogen atoms, and compounds comprising silicon atoms and polyether chains are used as auxiliaries and/or additives e).
40 The prepolymers containing isocyanate groups and obtained from the reaction of MDI and its higher homologues with polyether polyols preferably have an NCO content of from 22 to 30 % by weight and are liquid at room temperature.
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Isocyanates used as starting materials for preparing the prepolymers containing isocyanate groups are preferably mixtures of diphenylmethane diisocyanate isomers and polyphenylpolymethylene polyisocyanates, usually known as crude 5 MDI. In particular, use is made of mixtures which comprise al) from 45 to 65 % by weight of diphenylmethane 4,4'-diisocyanate, 10 a2) from 10 to 50% by weight of diphenylmethane 2,4'-diisocyanate, a3) from 0 to 1 % by weight of diphenylmethane 2,2'-diisocyanate and a4) from 45 to 1 % by weight of at least trifunctional polyphenylpolymethylene polyisocyanates.
Such products and their preparation are described in DE-A-44 11 781.
As polyether polyols, preference lS given to using trifunctlonal polyether polyols, in particular pure polyoxypropylene polyols.
The hydroxyl number of the polyether polyols is from 20 to 60 mg KOH/g.
The polyester polyols used according to the present invention as component b) are prepared by reacting at least bifunctional alcohols with at least bifunctional carboxylic acids.
30 The polyester polyols used according to the present invention are preferably bifunctional, possibly slightly branched, and have a hydroxyl number in the range from 10 to 100 mg KOH/g.
Suitable polyester polyols can be prepared, for example, from 35 organic dicarboxylic acids having from 2 to 12 carbon atoms, preferably aliphatic dicarboxylic acids having from 4 to 6 carbon atoms, and polyhydric alcohols, preferably alkanediols, having from 2 to 12 carbon atoms, preferably from 2 to 6 carbon atoms, and/or dialkylene glycols. Examples of suitable dicarboxylic 40 acids are: succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acids can be used either individually or in admixture with one another. In place of the 45 free dicarboxylic acids, it is also possible to use the corresponding dicarboxylic acid derivatives such as dicarboxylic esters of alcohols having from 1 to 4 carbon atoms or CA 0224269~ 1998-08-14 - BASF Aktiengesellschaft 970269 O.Z. 0050/48225 dicarboxylic anhydrides. Preference is given to using dicarboxylic acid mixtures of succinic, glutaric and adipic acids in weight ratios of, for example, 20 - 35: 35 - 50: 20 - 32, and in particular adipic acid. Examples of dihydric and 5 polyhydric alcohols, in particular alkanediols, dialkylene glycols and triols are:
Ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, l,4-butanediol, 1,5-pentanediol, 10 1,6-hexanediol, l,10-decanediol, glycerol and trimethylolpropane.
Preference is given to using ethanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or mixtures of at least two of the alkanediols mentioned, in particular mixtures of 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol. It is also 15 possible to use polyester polyols derived from lactones, eg.
~-caprolactone, or hydroxycarboxylic acids, eg. cl)-hydroxycaproic acid.
20 To prepare the polyester polyols, the organic, eg. aromatic and preferably aliphatic polycarboxylic acids and/or derivatives and polyhydric alcohols and/or dialkylene glycols can be polycondensed in the absence of catalysts or preferably in the presence of esterification catalysts, advantageously in an atmosphere of inert gases, eg. nitrogen, helium, argon, etc., in the melt at from 150 to 250OC, preferably from 180 to 220~C, under atmospheric pressure or reduced pressure to the desired acid number which is advantageously less than 10, preferably less than 2. According to a preferred embodiment, the esterification 30 mixture is polycondensed at the abovementioned temperatures to an acid number of from 80 to 30, preferably from 40 to 30, under atmospheric pressure and subsequently under a pressure of less than 500 mbar, preferably from 50 to 150 mbar. Suitable esterification catalysts are, for example, iron, cadmium, cobalt, 35 lead, zinc, antimony, magnesium, titananium and tin catalysts in the form of metals, metal oxides or metal salts. However, the polycondensation can also be carried out in the liquid phase in the presence of diluents and/or entrainers such as benzene, toluene, xylene or chlorobenzene to azeotropically distil off the 40 water of condensation. To prepare low-fogging polyester polyols, the polyester polyols obtained can be subjected to at least one additional distillation under reduced pressure, eg. in a thin-film and/or falling-stream evaporator.
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 To prepare the polyester polyols, the organic polycarboxylic acids and/or derivatives and polyhydric alcohols are advantageously polycondensed in a molar ratio of 1:1 - 1.8, preferably 1:1.05 - 1.2.
~he polyester polyols obtained have a functionality of preferably from 2 to 4, in particular from 2 to 3, and a molecular weight of from 1800 to 3600, preferably from 2200 to 3200.
As regards the other starting materlals for the process of the present invention, the following details may be provided.
As blowing agent c) for producing the flexible PU foams, use is 15 made, in particular, of water which reacts with isocyanate groups to form carbon dioxide. The amounts of water which are advantageously used are from 0.1 to 8 parts by weight, preferably from 2.5 to 6.0 parts by weight and in particular from 3.3 to 4.3 parts by weight, based on 100 parts by weight of the 20 polyhydroxyl compounds (b).
Also suitable as blowing agents are liquids which are inert toward the liquid polyisocyanate mixture (a) which has been modified with urethane groups and have boiling points below 80~C, 25 preferably below 50~C, in particular from -50~C to 30~C, at atmospheric pressure so that they vaporize under the action of the exothermic polyaddition reaction, and also mixtures of such physically acting blowing agents and water. Examples of such liquids which are preferably used are alkanes such as heptane, 30 hexane, n- and iso-pentane, preferably industrial mixtures of n-and iso-pentanes, n- and iso-butane and propane, cycloalkanes such as cyclopentane and/or cyclohexane, ethers such as furan, dimethyl ether and diethyl ether, ketones, such as acetone and methyl ethyl ketone, alkyl carboxylates such as methyl formate, 35 dimethyl oxalate and ethyl acetate and halogenated hydrocarbons such as methylene chloride, dichloromonofluoromethane, difluoromethane, trifluoromethane, difluoroethane, tetrafluoroethane, chlorodifluoroethanes, 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane 40 and heptafluoropropane. Mixtures of these low-boiling liquids with one another and/or with other substituted or unsubstituted hydrocarbons can also be used. Further suitable blowing agents are organic carboxylic acids such as formic acid, acetic acid, oxalic acid, ricinoleic acid and other carboxyl-containing 45 compounds.
CA 0224269~ 1998-08-14 BASF AktiengesellSchaft 970269 O.Z. 0050/48225 Blowing agents which are preferably used are chlorodifluoromethane, chlorodifluoroethanes, dichlorofluoroethanes, pentane mixtures, cyclopentane, cyclohexane and in particular water and also mixtures of at least 5 two of these blowing agents, eg. mixtures of water and cyclopentane and/or cyclohexane, mixtures of chlorodifluoromethane and l-chloro-2,2-difluoroethane and, if desired, water. Blowing agents which are not used are chlorofluorocarbons which damage the ozone layer.
The necessary amount of physically acting blowing agents can be determined experimentally in a simple manner as a function of the desired foam density and the amount of any water used and is from about 0 to 25 parts by weight, preferably from 0 to 15 parts by 15 weight, per 100 parts by weight of the polyhydroxyl compounds (b). It may be advantageous to mix the polyisocyanate mixtures (a) containing bound urethane groups with the inert, physically acting blowing agent and thus lower their viscosity.
Catalysts (d) used for producing the flexible foams according to the present invention are preferably compounds which strongly accelerate the reaction of the hydroxyl-containing compounds of the component (b) with the liquid MDI-based polyisocyanate 25 mixtures (a) containing bound urethane groups. Suitable catalysts are organic metal compounds, preferably organic tin compounds such as tin(II) salts of organic carboxylic acids, eg. tin(II) acetate, tin(II) octoate, tin(II) ethylhexanoate and tin(II) laurate, and dialkyltin(IV) salts of organic carboxylic acids, 30 eg. dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate and dioctyltin diacetate, and strongly basic amines, for example amidines such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tertiary amines such as triethylamine, tributylamine, dimethylbenzylamine, N-ethylmorpholine, 35 N-cyclohexylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylbutanediamine, N,N,N',N'-tetramethylhexane-1,6-diamine, bis(4-dimethylaminocyclohexyl)methane-pentamethyldiethylenetriamine, bis(dimethylaminoethyl) ether, 40 bis(dimethylaminopropyl)urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-aza-bicyclo[3.3.0]octane and preferably 1,4-diazabicyclo[2.2.2]octane and alkanolamine compounds such as triethanolamine, triisopropanolamine, N-methyldiethanolamine and N-ethyldiethanolamine and dimethylethanolamine.
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Further suitable catalysts are:
tris(dialkylaminoalkyl)-s-hexahydrotriazines, in particular tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine, tetraalkylammonium hydroxides, such as tetramethylammonium 5 hydroxide, alkali metal hydroxides, such as sodium hydroxide and alkali metal alkoxides such as sodium methoxide and potassium isopropoxide and also alkali metal salts of long-chain fatty acids having from 10 to 20 carbon atoms and possibly lateral OH
groups and combinations of the organic metal compounds and 10 strongly basic amines. Also suitable as catalysts are derivatives of morpholine such as N-methylmorpholine or N-ethylmorpholine.
Preference is given to using from 0.001 to 5 % by weight, in particular from 0.05 to 2 % by weight, of catalyst or catalyst combination, based on the weight of the polyhydroxyl compound 15 (b).
The reaction mixture for producing the flexible PU foams further comprises additives (e). According to the present invention, the reaction mixture comprises, as indicated above, compounds 20 comprising silicon atoms and polyether chains. These are preferably used in an amount of from 0.5 to 5 % by weight, based on the component b). These compounds are silicone-polyether copolymers. The products have an average molecular weight (Mw) of about 8000, with the molecular weight distribution being 25 relatively broad. The siloxane chain has an average length of about 40 (CH3)2SiO units and has an average of 5 polyether chains linked to it. The polyether chains preferably comprise ethylene oxide and propylene oxide in a ratio of 1:1 and have a hydroxyl group at the end. The molecular weight of the polyether chains is 30 about 1500-Such products are commercially available and are sold, forexample, by Goldschmidt AG under the name Tegostab~.
Further additives e) are, for example, surface-active substances, foam stabilizers, cell regulators, fillers, dyes, pigments, flame retardants, hydrolysis inhibitors, fungistatic and bacteriostatic substances.
Suitable surface-active substances are, for example, compounds which serve to aid the homogenization of the starting materials and may also be suitable for regulating the cell structure.
Examples which may be mentioned are emulsifiers such as the 45 sodium salts of castor oil sulfates or fatty acids and also amine salts of fatty acids, eg. diethylamine oleate, diethanolamine stearate, diethanolamine ricinoleate, salts of sulfonic acids, CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 eg. alkali metal or ammonium salts of dodecylbenzene- or dinaphthylmethanedisulfonic acid and ricinoleic acidi foam stabilizers such as siloxane-oxyalkylene copolymers and other organopolysiloxanes, ethoxylated alkylphenols, ethoxylated fatty 5 alcohols, paraffin oils, castor oil or ricinoleic esters, Turkey red oil and peanut oil and cell regulators such as paraffins, fatty alcohols and dimethylpolysiloxanes. Oligomeric polyacrylates having polyoxyalkylene and fluoroalkane radicals as side groups are also suitable for improving the emulsifying 10 action, the cell structure and/or stabilizing the foam. The surface-active substances are usually employed in amounts of from 0.01 to 5 parts by weight, based on 100 parts by weight of the polyhydroxyl compound (b).
15 For the purposes of the present invention, fillers, in particular reinforcing fillers, are the customary organic and inorganic fillers, reinforcing materials and weighting agents known per se.
Specific examples are: inorganic fillers such as siliceous minerals, for example sheet silicates such as antigorite, 20 serpentine, hornblends, amphiboles, chrysotile, zeolites, talc;
metal oxides, such as kaolin, aluminum oxides, titanium oxides and iron oxides, meta salts such as chalk, barite, aluminum silicates and inorganic pigments such as cadmium sulfide, zinc sulfide and also glass particles. Examples of organic fillers 25 are: carbon black, melamine, rosin, cyclopentadienyl resins and graft polymers.
The inorganic and organic fillers can be used individually or as 30 mixtures and are advantageously incorporated into the reaction mixture in amounts of from 0.5 to 50 % by weight, preferably from 1 to 40 % by weight, based on the weight of the components (a) and (b).
35 Suitable flame retardants are, for example, tricresyl phosphate, tris(2-chloroethyl) phosphate, tris(2-chloropropyl) phosphate, tris(1,3-dichloropropyl) phosphate, tris(2,3-dibromopropyl) phosphate and tetrakis(2-chloroethyl)ethylene diphosphate.
40 Apart from the halogen-substituted phosphates mentioned above, it is also possible to use inorganic flame retardants such as red phosphorus, hydrated aluminum oxide, antimony trioxide, arsenic oxide, ammonium sulfate, ammonium polyphosphate, expandable graphite and calcium sulfate or cyanuric acid derivatives such as 45 melamine or mixtures of at least two flame retardants such as ammonium polyphosphates and melamine and/or expandable graphite and, if desired, starch for making the (molded) flexible PU foams CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 produced according to the present invention flame resistant. In general, it has been found to be advantageous to use from 5 to 50 parts by weight, preferably from 5 to 25 parts by weight, of said flame retardants or mixtures per 100 parts by weight of the 5 components (a) and (b).
Further details regarding the abovementioned other customary auxiliaries and additives may be found in the specialist literature, for example the monograph by J.H. Saunders and K.C.
10 Frisch UHigh Polymersn, Volume XVI, Polyurethanes, Parts 1 and 2, Interscience Publishers 1962 and 1964, or the Kunststoff-Handbuch, Polyurethane, Volume VII, Carl-Hanser-Verlag, Munich, Vienna, 1st, 2nd and 3rd editions, 1966, 1983 and 1993.
To produce the flexible PU foams, the liquid polyisocyanate mixtures (a) containing urethane groups in bound form and compounds (b) containing at least two active hydrogen atoms can 20 be reacted in the presence of blowing agents (c), catalysts (d) and, if desired, additives (e) at, for example, from 10 to 100~C, preferably from 18 to 80~C, in such ratios that advantageously from 0.5 to 2, preferably from 0.8 to 1.3 and in particular about one, reactive hydrogen atom(s) bound to the starting component 25 (b) is/are present per NCO group and, if water is used as blowing agent, the molar ratio of equivalents of water to equivalents of NCO groups is advantageously 0.5 - 5:1, preferably 0.7 - 0.95:1 and in particular 0.75 - 0.85:1.
30 The flexible PU foams are advantageously produced in a multicomponent foaming process, where the starting components (b), (c), (d) and (e) as separate streams are combined in the mixing head of a high-pressure or low-pressure machine and the polyisocyanate component used is the polyisocyanate mixture 35 containing bound urethane groups, if desired in admixture with (c). The reaction mixture can be foamed in open or closed molds;
it is also suitable for the production of molded foams.
To produce the flexible PU foams, the reaction mixture is 40 advantageously introduced at from 18 to 80~C, preferably from 30 to 65~C, into an advantageously metallic, heatable mold. The mold temperature is usually from 20 to 90~C, preferably from 35 to 70~C. The reaction mixture is allowed to cure in the closed mold with compaction, eg. at degrees of compaction of from 1.1 to 8, 45 preferably from 2 to 6 and in particular from 2.2 to 4.
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 The flexible PU foams usually have free-foamed densities of, for example, from 20 to 60 g/l, preferably from 40 to 55 g/l and in particular from 45 to 52 g/l. The flexible PU foam moldings produced from such foam formulations can have an overall density 5 of from 36 to 55 g/l, preferably from 45 to 50 g/l, depending on the degree of compaction employed.
The flexible PU foams produced by the process of the present invention are suitable, for example, as seat cushions for 10 upholstered furniture, the molded flexible PU foams are suitable as upholstery elements, armrests, headrests, sun visors and safety coverings in vehicle interiors, preferably in motor vehicles and aircraft.
The flexible foams can be firmly bonded to textile materlals by the flame bonding process.
The invention is illustrated by the following examples:
Examples 1 to 7 The components indicated in Table 1 were combined to form a polyol component and were foamed together with a prepolymer from 25 the reaction of 37.4 parts by weight of diphenylmethane 4,4l-diisocyanate, 37.4 parts by weight of diphenylmethane 2,41-diisocyanate, 12.4 parts by weight of a mixture of diphenylmethane isomers and polyphenylpolymethylene polyisocyanates (crude MDI) and 12.9 parts by weight of a 30 polyoxypropylene polyol having a hydroxyl number of 42 mg KOH/g and an NCO content of 28.5 % by weight with adherence to the indices indicated in Table 1 by means of a Cannon-Vikinq low-pressure foaming machine.
The foams obtained had the properties shown in Table 2.
It can be seen that the elongation and tensile strength of the foams increase with an increasing amount of stabilizer without 40 the other properties being impaired.
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BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Examples 8 to 12 The procedure of Examples 1 to 7 was repeatedi the precise ratios of the starting materials are indicated ln Table 4 and the 5 properties of the foams are shown in Table 5.
Table 4 10 Example 8 9 10 11 12 Polyol 1 100.00100.00 100.00 100.00 100.00 Lupragen~ N 2010.620.62 0.62 0.62 0.62 Lupragen~ N 2060.180.18 0.18 0.18 0.18 15 Stabilizer 11.50 1.50 2.00 2.00 2.00 Water 4.50 4.50 4.50 4.50 4.50 Index 100 100 100 90 80 Polyol:Isocyanatel)87.4 87.5 87.0 78.3 69.6 ) Mixing ratio = 100 parts by weight of polyol: x parts by weight of isocyanate as indicated in the table.
Table 5 Example 8 9 10 11 12 Density [kg/m3]31.130.5 30.3 31.4 34.1 30 Compressive 2.4 2.7 2.5 2.1 2.0 strength 40%
[kPa] DIN 53 577 Compressive set13.713.9 10.8 13.7 11.5 [%] *
35 Tensile strength 98 110 101 103 105 [kPa]
Elongation [%]141 152 156 181 200 40 Indentation hard- 111 128 119 99 91 ness B [N] 40 %
Elasticity [%]15 17 15 13 15 * 50 % compression for 22 hours at 70~C
CA 0224269~ 1998-08-14 BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Examples 13 to 17 The procedure of Examples 1 to 7 was repeated; the precise ratios of the starting materials are indicated in Table 6 and the 5 properties of the foams are shown in Table 7.
Table 6 Example 13 14 15 16 17 10 Polyol 1 100.00 100.00 100.00100.00100.00 Lupragen~ N 201 0.74 0.740.74 0.74 0.74 Lupragen~ N 206 0.06 0.060.06 0.06 0.06 Stabilizer 1.50 1.50 2.002.00 2.00 15 Water 5.00 5-00 5-Index 100 100 90 80 110 Polyol:Isocyanatl~95.4 94.4 85 75.6 104 20 1) Mixing ratio = 100 parts by weight of polyol: x parts by weight of isocyanate as indicated in the table.
Table 7:
Example 13 14 15 16 17 Density [kg/m3] 27.9 26.2 27.4 26.5 32.2 Compressive 3.0 2.9 2.8 2.1 3.5 30 strength 40%
[kPa] DIN 53 577 Compressive set 18.6 31.2 26.4 38.4 11.2 [%] *
Tensile strength 108 102 120 102 103 35 [kPa]
Elongation [%]131 151 191 242 104 Indentation hard- 141 119 130 97 170 40 ness B [N] 40 %
Elasticity [%]19 22 19 19 22 45 * 50 % compression for 22 hours at 70~C
CA 0224269~ 1998-08-14 -BASF Aktiengesellschaft 970269 O.Z. 0050/48225 Description of the products used Lupragen~ N 201: 33 % strength solution of diazabicyclooctane in dipropylene glycol Tegostab~ N 8701: Stabilizer from Goldschmidt, Essen Lupragen~ N 206: Bis(N,N-dimethylaminoethyl) ether, 70 %
solution in dipropylene glycol Polyol 1 Polyesterol based on adipic acid, diethylene glycol and trimethylolpropane having an OH
number of 61 mg KOH/g;
Stabilizer 1 Silicone-polyether copolymer, mean molecular weight Mw 8000, molecular weight of the polyether chain about 2500, ratio of ethylene to propylene in the polymer chain about 1:1 CA 0224269~ 1998-08-14
Claims (8)
1. A process for producing flexible polyurethane foams by reacting a) polyisocyanates with b) compounds containing at least two active hydrogen atoms in the presence of c) blowing agents d) catalysts and also e) auxiliaries and/or additives, wherein prepolymers containing isocyanate and urethane groups and derived from diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates and polyether polyols are used as polyisocyanates a), polyester polyols are used as compounds b) containing at least two active hydrogen atoms, and compounds comprising silicon atoms and polyether chains are used as auxiliaries and/or additives e).
2. A process as claimed in claim 1, wherein the prepolymers a) containing isocyanate and urethane groups have an NCO content of from 22 to 30 % by weight.
3. A process as claimed in claim 1, wherein the polyesterols b) are 2- to 4-functional.
4. A process as claimed in claim 1, wherein the polyester polyols have molecular weights of from 1800 to 3600 g/mol.
5. A process as claimed in claim 1, wherein the compounds comprising silicon atoms and polyether chains are used in an amount of from 0.5 to 5 % by weight, based on component b).
6. A process as claimed in claim 1, wherein the compounds comprising silicon atoms and polyether chains are silicone-polyether copolymers.
7. A process as claimed in claim 1, wherein the compounds e) comprising silicon atoms and polyether chains comprise a siloxane chain with polyether chains linked thereto.
8. A process as claimed in claim 1, wherein the compounds e) comprising silicon atoms and polyether chains have an average molecular weight M w of 8000 g/mol.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19735488.2 | 1997-08-16 | ||
| DE19735488A DE19735488A1 (en) | 1997-08-16 | 1997-08-16 | Preparation of polyurethane soft foam |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2242695A1 true CA2242695A1 (en) | 1999-02-16 |
Family
ID=7839122
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002242695A Abandoned CA2242695A1 (en) | 1997-08-16 | 1998-08-14 | Production of flexible polyurethane foams |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0906926B1 (en) |
| AT (1) | ATE210159T1 (en) |
| CA (1) | CA2242695A1 (en) |
| DE (2) | DE19735488A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20210301069A1 (en) * | 2018-08-21 | 2021-09-30 | Dow Global Technologies Llc | Viscoelastic polyurethane foams |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10063496A1 (en) * | 2000-12-20 | 2002-07-04 | Bayer Ag | Polyurethane elastomers with improved hydrolysis stability |
| CN101815611A (en) | 2007-08-01 | 2010-08-25 | 陶氏环球技术公司 | Heat bonding polyurethane foams |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1478045A (en) * | 1973-12-03 | 1977-06-29 | Ici Ltd | Polyurethane foams |
| DE3406188C1 (en) * | 1984-02-21 | 1985-01-10 | Th. Goldschmidt Ag, 4300 Essen | Process for the production of flexible polyester urethane foams |
| DE3924082C1 (en) * | 1989-07-20 | 1990-09-27 | Th. Goldschmidt Ag, 4300 Essen, De | |
| DE4203918A1 (en) * | 1992-02-11 | 1993-08-12 | Basf Ag | METHOD FOR THE PRODUCTION OF FLUOROCHLORINE-HYDROGEN-FREE POLYURETHANE SOFT FOAMS USING POLYISOCYANATE MIXTURES ON DIPHENYLMETHANE DIISOCYANIZATE POLYISOCYANIZED ASYANIZED ASYANIZED ASYANIZED ASYANATE BASE |
-
1997
- 1997-08-16 DE DE19735488A patent/DE19735488A1/en not_active Withdrawn
-
1998
- 1998-08-10 DE DE59802312T patent/DE59802312D1/en not_active Expired - Lifetime
- 1998-08-10 AT AT98114990T patent/ATE210159T1/en not_active IP Right Cessation
- 1998-08-10 EP EP98114990A patent/EP0906926B1/en not_active Expired - Lifetime
- 1998-08-14 CA CA002242695A patent/CA2242695A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20210301069A1 (en) * | 2018-08-21 | 2021-09-30 | Dow Global Technologies Llc | Viscoelastic polyurethane foams |
| US11912815B2 (en) * | 2018-08-21 | 2024-02-27 | Dow Global Technologies Llc | Viscoelastic polyurethane foams |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0906926A1 (en) | 1999-04-07 |
| EP0906926B1 (en) | 2001-12-05 |
| DE19735488A1 (en) | 1999-02-18 |
| ATE210159T1 (en) | 2001-12-15 |
| DE59802312D1 (en) | 2002-01-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |