DE2444331A1 - PROCESS FOR MANUFACTURING SUPERELASTIC POLYURETHANE FOAMS (COLD FOAMS) - Google Patents

Description

Bayer Aktiengesellschaft 2444331

Central area of patents, trademarks and licenses

GM / Ru r ⁵ ° 9 Leverkusen, Bayerwerk

16. SEP.

Process for the production of super-elastic polyurethane foams (cold foams)

Foams with a wide variety of physical properties are made using the isocyanate polyaddition process from compounds with several active hydrogen atoms, in particular containing hydroxyl and / or carboxyl groups Compounds and polyisocyanates, optionally with the use of water, activators, emulsifiers, Foam stabilizers and other additives have long been manufactured on an industrial scale (see R. Vieweg, A. Höchtlen, Kunststoff-Handbuch, Vol. VII, Polyurethane, Carl-Hanser-Verlag Munich, 1966). This procedure can be used with a suitable choice of components to produce both elastic and rigid foams or all variants in between.

Flexible polyurethane foams have been widely used in the upholstery industry for the manufacture of seating and Back padding found. From these materials one expects a high level of seating comfort that is comparable with that of foams made from natural latex. Physically leaves The quality of the upholstery element is reflected by the compression factor, which is also known in American literature as Sag factor is designated (i.e. the quotient of the hardness number at 65 # Lger and 25 # indentation, with the entire Deformation is kept constant for one minute each) and the course of the force-deformation characteristics. Of the

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The compression factor should have a value above 2.5 in order to achieve good cushioning properties and the force deformation characteristics should not have a plateau, i.e. there should be little to very little force changes large but only a small change in the deformation occur. Attempts have already been made to reduce the compression factor of the To improve foams by adding inert fillers such as barium sulfate or calcium carbonate, however, this has Process major deficiency, since the addition of the fillers is very difficult and the other foam properties be worsened.

From a soft elastic foam, which is optimally suitable for upholstery purposes, is therefore to be required that it has a compression factor above 2.5 and that no plateau occurs in the force-deformation diagram, i.e. that when the force changes only slight changes in the deformation occur.

In the German Auslegeschriften 1 929 034 and 2 002 064 taught flexible polyurethane foams by reacting isocyanurate or allophanatized polyisocyanates, so-called "Modified polyisocyanates" to produce polyethers containing hydroxyl groups in the presence of amines as catalysts. This means that the polyisocyanate component must be modified before the actual foaming process.

Furthermore, it is proposed in the German Offenlegungsschrift 2 003 431 to convert undistilled polyurethane foams Phosgenation products of primary amines with amine numbers from 87 to 168 with a hydroxyl group Polyether in the presence of a non-polymeric polyol as a crosslinking agent, a blowing agent and a catalyst, but in the absence of a silicone stabilizer of the type of polyoxyalkylene ether-polydimethylsiloxane block copolymers, to manufacture.

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This method also has significant drawbacks in that the polyisocyanate used as the starting material is practical is a crude product that contains polyisocyanates of different functionality in different amounts and that has no standardized properties. For the production of foams from it, this means that continuously, im In extreme cases, from batch to batch of this isocyanate, recipe changes must be made to cope with the fluctuations balance in the activity of the isocyanate.

As mentioned, "modified isocyanates" are often used to produce flexible foams. Of the Foam manufacturers must, however, have additional storage tanks and other mechanical equipment for these products. for their promotion and dosage. In the case of a commercially available "modified isocyanate", the processor can do not choose the degree of crosslinking of this product yourself or determine. It has now been found that these disadvantages can be avoided if the "modified isocyanate" is used immediately is produced in a preliminary stage before foaming.

The present invention thus relates to a process for the production of cold-curing polyurethane foams by the known reaction of modified polyisocyanates with at least two reactive hydrogen atoms containing compounds with a molecular weight of 400 to 10,000 in the presence of water and / or organic blowing agents and optionally catalysts, foam stabilizers and other auxiliaries, characterized in that the modified polyisocyanate is produced in a preliminary stage immediately before foaming.

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For this purpose, ζ. B. the foaming mixing head, a further mixing head for mixing the (the) starting product (s) and upstream of the catalyst or catalyst mixture and a reaction section for carrying out the reaction.

The expression "immediately before foaming" is intended to mean that the modified isocyanate is taken directly after it has been produced is continuously fed to the foaming mixing head, so there is no storage. With intermittent foaming, ζ. B. in molded part production, but must be a Possibility of short-term interim storage to compensate for the continuous production of the modified Isocyanates and its intermittent foaming are provided. It is understandable that the aim is to make the residence time or response time as short as possible, which z. B. through the choice of reaction partners and / or use of particularly active catalysts / catalyst mixtures, increasing the amounts added of the same, and last but not least can be achieved by using elevated reaction temperatures. If necessary, a can after the reaction section Tempering zone can be connected downstream in order to bring the modified product to the optimum temperature for foaming bring. Usually the time between production of the modified polyisocyanate in the first mixing unit and foaming in a second mixing unit is 0.1 second to 20 minutes, preferably 1 second to 10 minutes.

Modified polyisocyanates are those polyisocyanates which contain carbodiimide, biuret, allophanate, Have urethane or isocyanurate groups. The production of these modified polyisocyanates is known per se. Thus, the production of allophanate groups can be used

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Polyisocyanates ζ, Β. according to the Belgian patent specification 763 529 take place, while the production of biuret groups containing polyisocyanates z. B. after the Teaching of British patent specification 889 050 or according to the German Patent 1 101 394 can be carried out. Polyisocyanates containing isocyanurate groups and processes for their production are z. B. in German patents 951 168, 1 022 789 and in British patents 821 158, 827 120, 856 372, 927 173, 920 O8O, 952 931, in American patents 3,154,522, 2 801 244, in French patent 1 510 342 as well as in the Belgian patent 718 994 mentioned. Also the production of polyisocyanates containing urethane groups is known per se and can, for. B. by reacting polyols with an excess of polyisocyanates take place. Suitable polyols are, for. B. those with a molecular weight of 62 to 5,000 in question, z. B. ethylene glycol, Diethylene glycol, polyethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, glycerine, trimethylolpropane and also alkylene oxide derivatives of these low molecular weight polyols mentioned for example, which result in higher molecular weight polyethers to lead. Polyesters containing hydroxyl groups and in the specified molecular weight range also come according to the invention in question.

As to be used for the production of the modified polyisocyanates Starting components are aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic Polyisocyanates into consideration, as z. B. von W. Siefken in Justus Iiiebigs Annalen der Chemie, 562, pages 75 to I36 are described, for example ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate,

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1,12-dodecane diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and 1,4-diisocyanate 3 and any mixtures of these isomers, 1-isocyanato-3 _and 3,5-trimethyl-5-isocyanatomethyl-cyclohexane (DAS 1 202 785), 2,4- and 2,6-hexahydrotoluylene diisocyanate and any mixtures of these isomers, hexahydro-1,3- and / or 1,4-phenylene diisocyanate, perhydro-2, ¹ I'- and / or - ^, ^ '- diphenylmethane diisocyanate, 1,3- and 1,4-phenylene diisocyanate, 2, ¹ I and 2,6-tolylene diisocyanate and mixtures of these isomers, diphenylmethane-2,4'- and / or -4,4'-diisocyanate, naphthylene-ljS-diisocyanate, triphenylmethane-4,4 ', 4 "-triisocyanate, polyphenyl-polymethylene polyisocyanates, as obtained by aniline-formaldehyde condensation and subsequent phosgenation and, for example, in the British Patent specifications 874 430 and 848 671 are described, perchlorinated aryl polyisocyanates, as described, for example, in German Auslegeschrift 1,157,601.

It is also possible to use the technical isocyanate production accumulating isocyanate groups containing distillation residues, optionally dissolved in one or more of the aforementioned polyisocyanates to be used. It is also possible to use any desired mixtures of the aforementioned polyisocyanates to use.

To prepare the modified polyisocyanates, metal catalysts, e.g. B. bismuth or tin compounds, used. Amines can be used both as cocatalysts or in place of the metal compounds alone Find. For catalyzing the trimerization reaction to produce this type of modified polyisocyanate are z. B. amines and compounds of the Mannich base type are well suited. The following is an example the preparation of the modified to be used according to the invention Isocyanates described:

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Test execution:

A crosslinker mixture, consisting of one or more catalysts that accelerate the crosslinking reaction and one or more short-chain, low molecular weight _{organic compounds containing several hydroxyl groups and / or amino groups O NH, -NH 2} ), is dosed into an HK mixing head by means of a Bosch pump , in which toluylene diisocyanate is injected at the same time via a second Bosch pump. After intensive mixing, the reaction mixture flows with a residence time of 20 to 60 seconds through a temperature-controlled pipe coil and then into an agitator mixer head. In this the now modified isocyanate is mixed with the other components, eg. B. the recipe given in Example 1, combined and foams in the usual way after exiting the mixing head.

The is also produced analogously by trimerization modified isocyanate obtained, for carrying out the modification z. B. assumed TDI and catalytic converter .

According to the invention to be used for foam production starting components are also compounds with at least two isocyanate-reactive hydrogen atoms with a molecular weight generally from 400 to 10,000. In addition to amino groups, thiol groups or compounds containing carboxyl groups, this is preferably understood to mean polyhydroxy ! compounds, especially two to eight hydroxyl groups containing compounds, especially those with a molecular weight of 800 to 10,000, preferably 1,000 to 6,000, z. B. at least two, usually two to eight, but preferably two to four, hydroxyl-containing polyesters, Polyethers, polythioethers, polyacetals, polycarbonates, Polyester amides, as they are known per se for the production of homogeneous and cellular polyurethanes.

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The polyester containing hydroxyl groups in question are, for example, reaction products of polyvalent, preferably divalent and possibly additionally trivalent Alcohols with polybasic, preferably dibasic, carboxylic acids. Instead of the free polycarboxylic acids, the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or their Mixtures can be used to produce the polyester. The polycarboxylic acids can be aliphatic, cycloaliphatic ^ be aromatic and / or heterocyclic in nature and optionally, e.g. by halogen atoms, substituted and / or unsaturated. Examples include: succinic acid, Adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic anhydride, Tetrahydr © phthalic anhydride, hexahydrophthalic anhydride, Tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, Glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimers and trimeric fatty acids such as oleic acid, optionally mixed with monomeric fatty acids, dimethyl terephthalate, Terephthalic acid bis-glycol ester. As polyhydric alcohols come ζ.B. Ethylene glycol, propylene glycol- (1,2) and - (1,3), Butylene glycol (1,4) and - (2,3), hexanediol (1,6), octanediol (1,8), Neopentyl glycol, cyclohexanedimethanol (1,4-bis-hydroxymethylcyclohexane), 2-methyl-1,3-propanediol, Glycerine, trimethylolpropane, hexanetriol- (1,2,6), butanetriol- (1,2,4), Trimethylolethane, pentaerythritol, quinite, mannitol and sorbitol, methyl glycoside, also diethylene glycol, Triethylene glycol, tetraethylene glycol, polyethylene glycol Dipropylene glycol, polypropylene glycols, dibutylene glycol and Polybutylene glycols in question. The polyesters can be proportionate have terminal carboxyl groups. Also polyesters from lactones, e.g. E-caprolactone or hydroxycarboxylic acids, e.g. ω-Hydroxycaproic acid can be used.

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Even those preferred according to the invention, at least two Usually two to eight, preferably two to three, hydroxyl-containing polyethers are those of the an known type and are e.g. by polymerizing epoxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, Styrene oxide or epichlorohydrin with itself, e.g. in the presence of BF ,, or by increasing it Epoxides, optionally in a mixture or in succession, on starting components with reactive hydrogen atoms such as Alcohols or amines, e.g. water, ethylene glycol, propylene glycol- (1,3) or - (t, 2), trimethylolpropane, 4,4'-dihydroxydiphenylpropane. Aniline, ammonia, ethanolamine, ethylenediamine manufactured. Also sucrose polyethers, such as those described in German Auslegeschriften 1 176 358 and 1 064 938 are possible according to the invention. Often those polyethers are preferred that are predominantly (up to 90 wt .- ^, based on all existing OH groups in the polyether) have primary OH groups. Also polyethers modified by vinyl polymers, such as those produced by polymerization of styrene, acrylonitrile in the presence of polyethers (American patents 3,383,351 » 3,304,273, 3,523,093, 3,110,695, German patent specification 1,152,536) are also suitable, as are polybutadienes containing OH groups.

According to the invention, low molecular weight crosslinkers can also be used active hydrogen atoms (molecular weight 32 - 400) are also used be e.g. B. those of the type mentioned above as starting components and starting components. Also hydrazine and its Derivatives as well as alkanolamines belong to it.

Among the polythioethers are in particular the condensation products of thiodiglycol with themselves and / or with others Glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acids or Amino alcohols listed. Depending on the co-components acts the products are polythio mixed ethers, polythio ether esters, Polythioether ester amides.

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As polyacetals come, for example, those from glycols, such as diethylene glycol, triethylene glycol, 4,4 ^! -Dioxäthoxy-diphenyldimethylmethan, hexanediol and formaldehyde preparable compounds in question. Polyacetals suitable according to the invention can also be prepared by polymerizing cyclic acetals.

Polycarbonates containing hydroxyl groups are those of the type known per se, which are produced, for example, by reacting Diols such as propanediol (1,3), butanediol (1,4) and / or hexanediol (1,6), Diethylene glycol, triethylene glycol, tetraethylene glycol with diaryl carbonates, e.g. diphenyl carbonate or Phosgene, can be produced.

The polyester amides and polyamides include, for example, those made of polyvalent saturated and unsaturated carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, Predominantly linear condensates obtained from diamines, polyamines and their mixtures.

Also poly which already contain urethane or urea groups hydroxyl compounds and optionally modified natural poly oils such as castor oil, carbohydrates, starch usable. Addition products of alkylene oxides with phenol-formaldehyde resins or also with urea-formaldehyde resins can be used according to the invention.

Representatives of these compounds to be used according to the invention are, for example, in High Polymers, Vol. XVI, "Polyurethanes, Chemistry and Technology ¹¹ , written by Saunders-Frisch, Interscience Publishers, New York, London, Volume I, 1962, pages 32-42 and pages 44 - 54 and Volume II, 1964, pages 5-6 and 198-199, and in the Kunststoff-Handbuch, Volume VII, Vieweg-Höohtlen, Carl-Hanser-Verlag, Munich, 1966, for example on pages 45 to 71, are described.

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2U4331 M.

According to the invention, water and / or volatile organic substances are also used as blowing agents. as organic blowing agents are e.g. acetone, ethyl acetate, halogen-substituted alkanes such as methylene chloride, chloroform, ethylidene chloride, vinylidene chloride, Monofluorotrichloromethane, chlorodifluoromethane, dichlorodifluoromethane, also butane, hexane, heptane or diethyl ether are possible. A driving effect can also be achieved by adding at Temperatures above room temperature with the elimination of gases, e.g. nitrogen, decomposing compounds, e.g., azo compounds such as azolesobutyronitrile. Further examples of propellants and details on the use of propellants are in the Kunststoff-Handbuch, Volume VII, edited by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, e.g. on pages 108 and 109, 453 to 455 and 507 to 510.

According to the invention, catalysts are also often used for foam production. Catalysts to be used are those of the type known per se, eg. B. tertiary amines, such as triethylamine, tributylamine, N-methylmorpholine, N-ethyl-morpholine, N-cocomorpholine, N, N, N ', N'-tetramethylethylenediamine, 1,4-diaza-bicyolo- (2.2 , 2) -octane, N-methyl-N'-dimethylaminoethyl-piperazine, N, N-dimethylbenzylamine, bis- (N, N-diethylaminoethyl) adipate, N, N-diethylbenzylamine, pentamethyl-diethylenetriamine, N, N-dimethylcyclohexylamine , N, N, N ¹ , N ¹ -tetramethyl-1,3-butanediamine, N, N-dimethyl-β-phenylethylamine, 1,2-dimethylimidazole, 2-methylimidazole. Mannich bases composed of secondary amines, such as dimethylamine, and formaldehyde, and ketones or phenols, such as acetone, methyl ethyl ketone, cyclohexanone, phenol, nonylphenol, bisphenol, are also suitable as catalysts.

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Hydrogen atoms active towards isocyanate groups tertiary amines are e.g. triethanolamine, trlisopropanolamine, N-methyl-diethanolamine, N-ethyl-diethanolamine, N, N-dimethyl-ethanolamine, and their reaction products with alkylene oxides, such as propylene oxide and / or ethylene oxide.

Silaamines with carbon-silicon bonds are also used as catalysts, as described, for example, in German patent specification 1 229 290, in question, e.g. 2,2,4-trimethyl-2-silamorpholine, 1,3-ethylaminomethyl-tetramethyl-disiloxane.

Nitrogen-containing bases such as tetraalkylammonium hydroxides and alkali metal hydroxides such as Sodium hydroxide, alkali phenolates such as sodium phenolate or alkali metal alcoholates such as sodium methylate are suitable. Also hexahydrotriazines can be used as catalysts.

According to the invention, organic metal compounds, in particular organic tin compounds, can also be used as catalysts be used.

Tin (II) salts are preferably used as organic tin compounds of carboxylic acids such as tin (II) acetate, tin (II) octoate, Tin (II) ethyl hexoate and tin (II) laurate and the tin (IV) compounds, e.g., dibutyl tin oxide, dibutyl tin dichloride, dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tin maleate or dioctyltin diacetate into consideration. It goes without saying that all of the abovementioned catalysts can be used as mixtures will.

Further representatives of catalysts to be used according to the invention and details about the mode of operation of the catalysts are given in the Kunststoff-Handbuch, Volume VII by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, e.g. on pages 96 to 102.

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The catalysts are generally used in an amount between about 0.001 and 10% by weight, based on the amount of compounds, with at least two isocyanate-reactive hydrogen atoms and a molecular weight of
400 to 10,000 are used.

According to the invention, surface-active additives (emulsifiers and foam stabilizers) can also be used. Suitable emulsifiers are, for example, the sodium salts of castor oil sulfonates or of fatty acids or salts of fatty acids with amines such as oleic diethylamine or stearic acid diethanolamine. Also alkali or ammonium salts of
Sulfonic acids such as from dodecylbenzenesulfonic acid or
Dinaphthylmethanedisulfonic acid or fatty acids such as ricinoleic acid or polymeric fatty acids can be used as surface-active additives.

Polyether siloxanes are optionally used as foam stabilizers, especially water-soluble representatives, in question. These connections are generally constructed in such a way that a copolymer of ethylene oxide and propylene oxide with a polydimethylsiloxane radical connected is.

According to the invention, reaction retarders,
For example, acidic substances such as hydrochloric acid or organic acid halides, and also cell regulators of the type known per se such as paraffins or fatty alcohols or dimethy / polysiloxanes
as well as pigments or dyes and flame retardants of the type known per se, for example tris-chloroethyl phosphate, tricresyl phosphate or ammonium phosphate and -p'olyphosphate, also stabilizers against aging and weathering influences, plasticizers and
fungistatic and bacteriostatic substances,
Fillers such as barium sulfate, kieselguhr, carbon black or slurry. chalk can also be used.

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Further examples of surface-active additives and foam stabilizers and cell regulators, reaction retarders, stabilizers, flame-retardant substances, plasticizers, dyes and fillers and fungistatic and bacteriostatic substances and details of the use and mode of action of these additives are given in the Kunststoff-Handbuch, Volume VH published by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, for example on pages 103 to 113.

According to the invention, the reaction components are reacted by the one-step process known per se, the prepolymer process or the semiprepolymer process, often using mechanical devices, for example those described in US Pat. No. 2,764,565 . Details about processing devices that can also be considered according to the invention are described in the Kunststoff-Handbuch, Volume VH, published by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, for example on pages 121 to 205 .

According to the method according to the invention in the form of blocks or foams produced as molded parts are used, for example, as cushioning materials, mattresses, packaging materials, shock-absorbing automobile parts, foils used for lamination purposes and as insulating materials.

If the foaming is carried out in molds, this is done entered the reaction mixture in a form. Metal, e.g. B. aluminum or plastic, z. B. epoxy resin in question. The foamable reaction mixture foams up in the mold and forms the molded body.

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The foam molding can be carried out so that the molded part has a cell structure on its surface, but it can also be carried out so that the molded part has a has compact skin and a cellular core. According to the invention you can proceed in this connection in such a way that you enter so much foamable reaction mixture into the mold, that the foam formed just fills the shape. But you can also work in such a way that you get more foamable reaction mixture enters the mold than is necessary to fill the inside of the mold with foam; is. In the latter The case is thus worked under "overcharging"; such a procedure is e.g. B. from the American Patent specification 1 178 490 or from the American patent specification 3 182 104 known.

In the case of foam molding, there are many known ones Release agent also used.

Cold-curing foams in particular are according to the invention (see British patent specification 1,162,517, German laid-open specification 2,153,086).

The process of the invention is illustrated by the following examples explained in more detail:

example

100 parts by weight of a polyether with an OH number of .470, which by Reaction of propylene oxide with ethylenediamine has been obtained, 0.5 parts by weight of bismuth octoate as a catalyst and 750 parts by weight of toluene diisocyanate (ratio of 2,4: 2,6 isomers such as 80: 20 percent by weight) are in one

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Mixing unit mixed with one another and in a subsequent ^{reaction section heated to 22 0} C with a residence time of 25 seconds. reacted and then immediately mixed in the mixing head of a conventional foaming system with the following components and foamed in a known manner; 100 parts by weight of a polyether with an OH number of 28, which has been obtained by reacting trimethylolpropane with propylene oxide and then ethylene oxide, 3 * 5 parts by weight of water, 0.2 part by weight of triethylenediamine as a catalyst, 0.3 part by weight of a commercially available foam stabilizer (stabilizer B 3207 der Th, Goldschmidt AG, Essen), 2.0 parts by weight of trichloroethyl phosphate, 4.0 parts by weight of diethanolamine.

For foaming with these components, 64.4 parts by weight of the modified obtained according to the above procedure are used Polyisocyanate with an NCO content of 35 percent by weight has, used. The key figure is 95

A highly elastic polyurethane foam with ^{a density of 28 kg / m 5} and a SAG factor of 2.8 is obtained, the force deformation characteristics of which have practically no plateau and which therefore has excellent cushioning properties. The compressive strength is 2.40 KPa at 40 % deformation.

Example 2:,

Example 2 is carried out analogously to Example 1, except that 1200 parts by weight are used instead of 750 parts by weight of tolylene diisocyanate and 3.0 parts by weight of diethanolamine are used instead of 4.0 parts by weight. The amount of modified polyisocyanate with an NCO content of 41.4 % added is 50.1 parts by weight (code 97).

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Pr

The foam obtained is super elastic, has a density of 26 kg / m ^ ⁵ with a compressive strength of 0.88 KPa at 40 % deformation and a SAG factor of 3.1

Example 3:

The procedure is as described in Example 1, but only 35.2 parts by weight of the modified isocyanate with an NCO content of 35% are used and an additional 21.2 parts by weight of toluene dxisocyanate (80:20) are added, so that an NCO content is calculated of 40 percent by weight for this mixture results in a highly elastic foam with a density of 26 kg / m ^ with a compressive strength of 1.10 KPa at 40 % deformation and a SAG factor of 2.9.

Example 4:

100 parts by weight of a polyether with an OH number of 85O, which has been obtained by reacting propylene oxide with trimethylolpropane, 15 parts by weight of ethylene glycol, 1.0 part by weight of bismuth octoate as a catalyst and 2,400 parts by weight of toluylene diisocyanate (80:20) are mixed with one another in a mixing unit and mixed in a subsequent reaction zone, which is heated to 5O ⁰ C, lake at a residence time of 25th reacted and then mixed in the mixing head of a conventional foaming system with the following components and foamed in a known manner: 100 parts by weight of a polyether with an OH number of 28, which has been obtained by reacting trimethylolpropane with propylene oxide and then ethylene oxide, 3.5 parts by weight of water, 0.15 parts by weight of triethylenediamine, 4.0 parts by weight of diisopropanolamine, 2.0 parts by weight of trichloroethyl phosphate, 1.0 part by weight of triethanolamine.

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For foaming with these components, 54.4 parts by weight (code 97) of that obtained in accordance with the above procedure modified polyisocyanate, which has an NCO content of 41.8 percent by weight, is used.

A super-elastic polyurethane foam with a density of 29 kg / nr with a compressive strength of 1.47 KPa is obtained 40 Ji deformation. The force deformation characteristics show practical no plateau.

Example 5:

100 parts by weight of a polyether with OH number 915 _} obtained by reacting propylene oxide with trimethylolpropane, 6.7 parts by weight of a 33 # solution of triethylenediamine in dipropylene glycol as a catalyst, 1,450 parts by weight of tolylene diisocyanate (80:20) are mixed together in a mixer mixed and in a subsequent reaction section, which is tempered to 25 C, with a residence time of 90 seconds. reacted and then mixed in the mixing head of a conventional foaming system with the following components and foamed in a known manner: 100 parts by weight of a polyether with an OH number of 28, which has been obtained by reacting trimethylolpropane with propylene oxide and then ethylene oxide, 3 _} 5 parts by weight of water, 0.2 part by weight of triethylenediamine, 0.2 part by weight of a commercially available foam stabilizer (stabilizer B 3207 from Th. Goldschmidt AG, Essen), 2.0 parts by weight of trichloroethyl phosphate, 30 parts by weight of diethanolamine.

For foaming with these components, 52.9 parts by weight (code 95) of that obtained in accordance with the above procedure modified polyisocyanate, which has an NCO content of 40.4 percent by weight, is used.

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The highly elastic foam has a ^{density of 31 kg / m 3} with a compressive strength of 1.67 KPa and 40 % deformation.

Example 6;

100 parts by weight of the polyether with OH number 915 from Example 5, 1.1 parts by weight of tin dioctoate, 3.3 parts by weight of a 33% strength solution of triethylenediamine in dipropylene glycol, 1,430 parts by weight of toluylene diisocyanate (80:20) are mixed with one another in a mixer and in a subsequent reaction section, which ^{is tempered to 40 0} C, with a residence time of 70 seconds. reacted and then mixed in the mixing head of a conventional foaming system with the components listed in Example 5 and foamed in a known manner, 59.2 parts by weight of the modified polyisocyanate obtained according to the above procedure with an NCO content of 36.2 percent by weight being added. The number is 95.

The highly elastic foam has a ^{density of 34 kg / m 3} with a compressive strength of 3.43 KPa and 40 % deformation.

Example 7:

Mixed 95 parts by weight of the polyether of OH number 915 from Example 5, 5.0 parts by weight ethylene glycol, 2.0 parts by weight tin dioctoate _s are 1,460 parts by weight of tolylene diisocyanate (80:20) in a mixing unit with one another and in a subsequent reaction section, which at 25 ° C is tempered, with a residence time of 23 seconds. brought to reaction and then mixed in the mixing head of a conventional foaming system with the components listed in Example 5 and

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foamed in a known manner, 52.9 parts by weight of the modified polyisocyanate obtained according to the above procedure with an NCO content of 40.3 percent by weight are added. The number is 95.

The highly elastic foam has a ^{density of 34 kg / m-5} with a compressive strength of 2.06 KPa and 40 % deformation.

Example 8:

1.500 parts by weight of tolylene diisocyanate (80:20), 1.0 part by weight of bismuth octoate, 2.0 parts by weight of a Mannich base from dimethylamine, phenol and formaldehyde as a catalyst are mixed in a mixing unit with one another and in a subsequent reaction zone, which is heated to 100 ⁰ C, reacted with a dwell time of 8 minutes, then cooled down with a dwell time of 2 minutes in a cooling section set to 20 C and then mixed with the components listed in Example 5 in the mixing head of a conventional foaming system and foamed in a known manner, with 57, 0 parts by weight of the modified polyisocyanate obtained in accordance with the above procedure and having an NCO content of 37.6 percent by weight are added. The number is 95.

The highly elastic foam has a ^{density of 4M kg / m · 5} with a compressive strength of 4.91 KPa with 40 % deformation.

Le A 15 932 - 20 -

609813/0893

Example 9?

For the preparation of the modified isocyanate is carried out as described in Example 8, but the residence time is 3 minutes in the heated to 100 ⁰ C and the reaction zone residence time in the set at 20 ⁰ C cooling section 2 minutes. The modified polyisocyanate obtained in this way with an NCO content of 45.4 percent by weight is foamed using the components specified in Example 5. According to code 95, 47.0 parts by weight of the isocyanate are used.

The highly elastic foam has a ^{density of 34 kg / m 5} with a compressive strength of 1.18 KPa with 40 % deformation.

Le A 15 932 - 21 -

609813/0893

Claims (1)

Claim: ZL Process for the production of cold-curing polyurethane foams by the known reaction of modified polyisocyanates with compounds containing at least two reactive hydrogen atoms and having a molecular weight of 100 to 10,000 in the presence of water and / or organic blowing agents and optionally catalysts, foam stabilizers, crosslinking agents containing active hydrogen atoms and having a molecular weight of 32 to 400 , and other auxiliaries, characterized in that the modified polyisocyanate is prepared in a preliminary stage immediately before foaming. Le A 15 932 - 22 - 809813/0893