DE19546367A1 - Easily prepared isocyanate prepolymer mixture based on oligo- or polysaccharide - Google Patents

Abstract

An isocyanate prepolymer mixture (I) containing urethane groups and reactive isocyanate (NCO) groups is claimed. It has an NCO content of 2.5-30 wt.% and is obtained by reacting (a) di- and/or polyisocyanate(s) with (b) a solution or emulsion containing (b-1) oligosaccharide(s) and/or polysaccharide(s), (b-2) non-aqueous solvent(s) reacting with (b-1) and optionally (b-3) polyhydroxyl compound(s). Also claimed is a method of producing compact or cellular polyurethane, especially polyurethane foam from (I), the polyurethane per se and mouldings of this polyurethane.

Description

The present invention relates to saccharide-containing isocyanate prepolymer mixtures. The invention also relates to methods for Preparation of such isocyanate prepolymer mixtures. Finally is The invention also relates to the use of isocyanate prepoly mer mixtures according to the invention for the preparation of polyurethanes (PU), in particular of foamed moldings based on polyurethane as well as methods for this.

Polysaccharides, especially starch, have always been known not only as Food, but also as an industrial raw material, eg. B. in the chemi industry. Representations of polysaccharides and starch included: R.L. Whistler et al., in: Kirk-Othmer, Encyclopedia of Chemi Cal Technology, 3rd ed., 1983, Vol. 21, pp. 492-507, "Starch"; P.A. Sandford et al., Polysaccharides, Academic Press, 1983, vol. 2, p. 411-490, "Industrial Utilization of Polysaccharides"; and A. Guilbot et al., in: Polysaccharides, Academic Press, 1985, Vol. 3, pp. 209-282, "Starch".

Basically, starch has been used in two different ways so far Ways of making polyurethanes used. On the one hand served the strength as a source of raw materials for the synthesis of low molecular weight  gangrene for the production of polyurethane building blocks. on the other hand native starch was also undegraded and used as a solid in polyurethanes incorporated.

Known is the use of starch as a synthesis building block by This is degraded to glucosides especially in acidic medium and the polyols produced in this way by subsequent alkoxylation or Esterification can be modified. Such a method is disclosed in US-A 3,165,508 and US-A 3,541,034, wherein the starch with a Polyol is reacted in the presence of an acid and at the same time or is then alkoxylated with an alkylene oxide. The resulting Polyoxyalkylene ether is then treated with an organic polyiso cyanate reacted to polyurethane foams. A similar procedure is Also described in US-A 3,457,178, wherein the phosphoric acid to the Hydroly se of strength is used. The thus existing phosphorus gives polyurethane foam produced non-burning properties. In US Pat. No. 3,957,702 describes polyurethane foams by reacting organi rule polyisocyanates with phosphorus-containing starch polyethers or Starch polyether hydrolyzates prepared. The phosphor gets through Reaction of the corresponding starch materials with polyphosphoric acid introduced. In this way, flame-resistant foams can be produced become.

In addition to the above reactions of polyurethanes with Polysac chariden or strengths is also the implementation of polyurethanes with esterified polysaccharides known. So are starch and cellulose esters low and high degree of substitution commercially available. Especially Acetates are on the most catalyzed by pyridine reaction with Acetic anhydride readily available, such as. In R.L. Whistler, Starch, "Starch Esters ", Academic Press, 1984, pages 332 to 342. Through the  Esterification increases the reactivity of the polysaccharides or starch, their compatibility with other non-polar components improved, and Polyurethanes with improved properties are obtained. Nachtei lig is in the methods described in the literature that the esters must be worked up to excess starting materials and Remove catalysts. So have to carry out the reaction in solvents these are removed before use in polyurethane systems become. In the article "Reactivity of modified starches with isocyanates" by EH Otey et al., Die Stärke, 1972, 24/4, pages 107-110 Starch modified by esterification or etherification and the influence this modification on the reactivity of the starch with isocyanates examined. The maximum reactivity of the modified starches was at a degree of substitution of 0.7 before, wherein in this substitution Grade hardened urethane paste, which consists of batches with 20% of starch were produced which showed maximum fracture energy. DE-PS 41 14 185 describes wet strength, thermoplastic starch materials, the from amylose-rich starches recoverable, sparingly soluble in water Starch acyl compounds and from biodegradable plasticizers exist, these starch materials are biodegradable. In WO 92/13894 is a radiation polymerizable starch ester urethane described containing an ester of a C₁-C₄ carboxylic acid and an ethyle unsaturated, bonded to the starch via a urethane bond Group contains.

As described above, the incorporation of phosphorus in polyurethane Foam to an improved fire behavior of the starchy Polyurethane foams lead. This effect can be amplified if the strength in combination with synergistic flame retardancy is used. Disadvantageous when incorporating starch in polyurethane ne are often deteriorated mechanical properties of polyurethane  shares, since the starch particles usually act only as a filler and not chemically incorporated into the polyurethane matrix. US-A 3,405,080 describes the compression of a non-foamed di-isocyanate prepolymer with high pressure starch (10,000 psi = 700 bar) and at Tempe between 70 and 100 ° C, to a reaction between the starch and the prepolymer. In GB-A 1 440 831 Polysaccharides, such as starch, incorporated in polyurethane foams by with the polyisocyanate, a catalyst for the polymerization of Isocyanate and a blowing agent are mixed. The presence of the Polysaccharide is said to be a foam with greater foam stability and lead to better fire behavior. Also in DE-OS 24 48 216 is a Carbohydrate, such as sugar, starch or cellulose as a filler in polyu Rethanschäume incorporated. The resulting foams have an increase te hardness and improved fire resistance and form at Ver burn coal, which is the dripping of burning molten Polyurethane prevented. In US-A 4,156,759 are polyurethane foams described that contain an amylose material by an antioxidant tion medium or the removal of oxidizable substances is stabilized.

From EP-A 0 003 160 are semi-flexible, starch-containing polyurethane foams with open cell structure known to be at a 20-25% lower Density than conventional polyurethane foams good mechanical properties show. In DE-OS 31 06 246 are filled with starch polyurethane Anhartschäume disclosed in which to improve application technology shear properties at least in part by so-called "Quellstärke" is replaced, the natural grain structure by heat wet strength has been destroyed. GB-A-2 094 315 highly elastic polyurethane foams made using starch as charring element and an intumescent catalyst (eg. Ammonium polyphosphate). In case of fire, char these  Foams. The flame retardants described in US-A 4,458,034, not dripping soft foams contain in addition to the usual ingredients Flame retardant and a polyol with respect to the isocyanate component non-reactive hydroxyl groups, in case of fire the flame retardant medium and the (unreacted) polyol react with each other Formation of a non-dripping, carbon-rich layer. In DE-OS 38 44 048 are flame-retardant, flexible polyurethane flexible foams made using flame retardants, the melamine and If necessary, contain starch and an additional flame retardant. WHERE 91/16403 discloses fire retardants which are a carbohydrate or a Starch as a binder and a dehydrating agent, eg. B. phosphate salts, contain. These fire retardants are either by admixture to the desired substance itself, z. B. by admixing as a filler in Polyurethanes, or by subsequent treatment of a raw material applied by impregnation.

To the reaction between the numerous existing, however largely to promote inert hydroxyl groups of the starch and the isocyanates is previously proposed to dissolve the starch in water and this Implement solution with isocyanates. However, contain aqueous starch solutions even at high starch concentrations and thus accordingly high viscosities high water surplus, so that in this Case the desired starch-isocyanate reaction from the predominant Water isocyanate reaction is covered. US-A 4,291,129 describes the Preparation of flame retardant polyurethane foam using from u. a. an aqueous carbohydrate solution, wherein the water as a carrier serves for the carbohydrates and other inorganic salts present. The foams produced maintain their structural integrity in case of fire at. WO 83/02120 describes polyurethane foams which Flame retardant can be made by adding a flame retardant  by means of, and are prepared by reacting a carbohydrate, Polyisocyanate and water in the presence of a surfactant and a catalyst. A method for dissolving starch in ver various solvents that contribute to the formation of Wasserstoffbrückenbin tions are capable, is described in DE-OS 41 43 132. this will achieved by removal of the chemically and physically bound Oxygen from the system and shearing, resulting in solutions with up to 10% strength can be produced. However, this procedure appears very cumbersome and technically difficult to realize.

The object of the present invention was novel isocyanate prepolymer mixtures provide. Another task of the inventor The idea was to specify such isocyanate prepolymer mixtures, to oligosaccharide and / or polysaccharide-containing polyurethanes can be further processed, the reactivity of the oligo- and Polysaccharides should be increased so that they are easily absorbed into the polyurethane Anmatrix would be involved. This should costly Ver to be avoided.

This object is achieved by isocyanate prepolymer mixtures, such as they are defined in the claims. The inventive method for the preparation of such isocyanate prepolymer mixtures and their Use for the production of polyurethanes and polyurethane products and methods thereof are also defined in the claims. before Preferred embodiments of the invention will become apparent from the following Description and the dependent claims.

Advantageously, according to the invention, a natural substance, namely a renewable polyhydroxyl compound used.  

Surprisingly, it has been found that the reactivity of Saccharomyces which is increased when oligosaccharides or polysaccharides reduced Molecular weight in the form of a solution or emulsion in non-aqueous, However, compared to a di- or polyisocyanate component reactive Lö be used in the polymerization. This will be the in connection with the processing of solid polysaccharides in the Literature described difficulties such as lack of reactivity, Solid handling or the presence of oversized, the reaction domi the amount of water used, especially when using Polysaccharides of very high molecular weight occur avoided.

The isocyanate prepolymer mixtures according to the invention, which contain urethane groups and reactive isocyanate groups, are formed from the reaction
b₂₁) with at least one di- and / or polyisocyanate
b₂₂) of a solution or emulsion containing
b _22i ) at least one oligosaccharide and / or polysaccharide and
b _22ii ) at least one non-aqueous, compared to the di- and / or polyisocyanate b₂₁) reactive solvent and optionally
b _22iii ) at least one polyhydroxyl compound.

The isocyanate prepolymer mixture according to the invention is characterized by the fact that it has a -N = C = O content of 2.5 to 30 wt .-%, Bezo gene on the total weight of the isocyanate prepolymer mixture has. Before geous enough, the solution or emulsion contains b₂₂)
b _22i ) from 99 to 50% by weight of at least one oligosaccharide and / or polysaccharide,
b _22ii ) 1 to 50 wt .-% of at least one non-aqueous, compared to the isocyanate _component b _22i ) reactive solvent and
b _22iii ) 0 to 49 wt .-% of at least one polyhydroxyl compound, based on the total weight of the solution or emulsion b₂₂).

The ratio of the three components b _22i ), b _22ii ) and b _22iii ) is _preferably such that 90 to 60% by weight, in particular 80 to 65% by weight, of component b _22i ), 10 to 40% by weight. %, in particular 20 to 35 wt .-%, of component b _22ii ) and 0 to 30 wt .-%, in particular 0 to 15 wt .-%, of component b _22iii ) together 100 wt .-% of the solution or emulsion b₂₂ ) form. Preferably, the isocyanate prepolymer mixture is obtainable from the reaction of 20 to 90 wt .-%, preferably 25 to 80 wt .-%, in particular 30 to 70 wt .-%, of the di- and / or Polyisocya nats b₂₁) with 10 to 80 wt .-%, preferably 20 to 75 wt .-%, in particular 30 to 70 wt .-%, of the solution or emulsion b₂₂), based on the total weight of the isocyanate prepolymer mixture.

The isocyanate prepolymer mixture preferably has an -N = C = O content from 10 to 25 wt%, with the most preferred isocya nat-prepolymer mixture a -N = C = O content of 10 to 20 wt .-% Has.

As suitable di- and / or polyisocyanates b₂₁) following Isocya nate be used:

Alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene radical, such as z. B. 1,12-dodecane diisocyanate, 2-ethyl-tetramethylene-diisocyanate-1,4, 2-methyl-pentamethylene-diisocyanate-1,5, 2-ethyl-2-butyl-pentamethylene-di isocyanate-1,5, tetramethylene-diisocyanate-1,4 and preferably hexamethyl len-1,6-diisocyanate; cycloaliphatic diisocyanates, such as. B. cyclohexane-1,3- and -1,4-diisocyanate and any mixtures of these isomers, 1-iso cyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (Isophorone diisocya  nat), 2,4- and 2,6-hexahydrotoluylene diisocyanate and the corresponding Isomer mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane diisocyanate and the corresponding isomer mixtures, and preferably aromati sche di- and polyisocyanates, such as. B. 2,4- and 2,6-toluene diisocyanate and the corresponding isomeric mixtures, 4,4'-, 2,4'- and 2,2'-diphenyl methane diisocyanate and the corresponding isomer mixtures, mixtures from 4,4'- and 2,4'-diphenylmethane diisocyanates, polyphenyl polymethylene polyisocyanates, mixtures of 4,4'-, 2,4'- and 2,2'-diphenylmethane dii socyanates and polyphenyl polymethylene polyisocyanates (crude MDI) and Mixtures of crude MDI and toluene diisocyanates. The organic ones Diisocyanates and polyisocyanates may be used individually or in the form of their mixtures be used.

As organic polyisocyanates have proven mixtures of diphe nylmethane diisocyanates and polyphenyl polymethylene polyisocyanates, preferably those having a diphenylmethane diisocyanate content of at least 35% by weight, e.g. B. from 45 to 95 wt .-% and in particular of 48 to 60 wt .-%, so that such crude MDI compositions particularly preferred application. Most preferred 4,4'-methylenedi (phenyl isocyanate) (MDI).

As component b _22i ) suitable oligosaccharides and / or polysaccharides are saccharides of reduced molecular weight, in particular partially degraded natural polysaccharides, eg. B. from native starches. Partially degraded starches are commercially available inexpensively and are easily recovered via acidic or enzymatic degradation from native starches. The degree of degradation is generally described by the dextrose equivalent value (DE value), with starch completely degraded to dextrose having a DE of 100. The DE value is the percentage of reducing sugars calculated as D-glucose in the dry matter. While native starches in the molecular weight range 10⁵ to 10⁸, a DE value of 20 corresponds to a molecular weight range of 10² to 10⁵. Preference is given to oligosaccharides obtained from native starches with dextrose equivalent values of from 5 to 50, in particular from 10 to 30.

Suitable solvents b _22ii ) are all nonaqueous solvents which are capable of dissolving oligosaccharides and polysaccharides and are reactive towards the isocyanate component b₂₁). Preferably, these solvents are non-reactive with the saccharides. Moreover, it is preferred if the solvents can form an emulsion with the other, typically nonpolar, components of the polyol component. Preferred solvents are polar higher polyols, in particular glycols, or nitrogen-containing compounds, in particular C₂- to C₅-alkanolamines, z. As triethanolamine, or C₁ to C₅-alkyl-C₂- to C₅-alkanolamines, such as methyldiethanolamine. Most preferred is glycerin.

In a preferred embodiment of the invention, the oligosaccharide-containing and polysaccharide-containing solutions of components b _22i ) and b _22ii ) are _emulsified with a polyhydroxyl compound b _22iii ) as defined below.

The solutions or emulsions obtained in this way are for Preparation of the polyurethane parts of the invention are particularly suitable. The processing of the saccharide-containing solutions or emulsions is easily possible. Even when using saccharide-containing Emul ions, the polyurethane reaction is not impaired, since at the beginning this reaction, the polyol and isocyanate component are immiscible and first form an emulsion.  

Suitable polyhydroxyl compounds b _22iii ) have a functionality of 2 to 8 and a hydroxyl number of 25 to 500 and preferably consist of polyhydroxyl compounds, which are in particular selected from the group of polythioether polyols, polyester amides, hydroxyl-containing polyacetals, hydroxyl-containing aliphatic polycarbonates, polyester polyols, polymer-modified polyether polyols, preferably polyether polyols and mixtures of at least two of said polyhydroxyl compounds.

Suitable higher molecular weight polyhydroxyl compounds, as used in b _22iii ), have, as already stated, expediently a functionality of 2 to 8 and a hydroxyl number of 25 to 500, wherein for the production of flexible PU foams preferably polyhydroxyl compounds having a functionality of preferably 2 to 3 and a hydroxyl number of preferably 30 to 80 and for the produc- tion of hard PU foams preferably polyhydroxyl compounds having a functionality of preferably 3 to 8 and especially 3 to 6 and a hydroxyl number of preferably 100 to 500 zweckmäßigerwei se application. The polyhydroxyl compounds used are preferably linear and / or branched polyester polyols and in particular linear and / or branched polyoxyalkylene polyols, with polyhydroxy compounds being particularly preferred from renewable natural products and / or chemically modified renewable natural products. Suitable polyhydroxyl compounds b _22iii ) are also polymer-modified polyoxyalkylene polyols, polyoxyalkylene polyol dispersions and other hydroxyl-containing polymers and polycondensates having the above-mentioned functionalities and hydroxyl numbers, for example, polyamide ramide, polyacetals and / or polycarbonates, especially those consisting of diphenyl carbonate and hexanediol -1.6 are prepared by transesterification, or mixtures of at least two of said higher molecular weight polyhydroxyl compounds b _22iii ).

Polyester polyols suitable as component b _22iii ) may, for example, be selected from organic dicarboxylic acids having 2 to 12 carbon atoms, preferably aliphatic dicarboxylic acids having 4 to 6 carbon atoms and polyhydric alcohols, preferably alkanediols having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms, dialkylene glycols and / or alkanetriols having from 3 to 6 carbon atoms. Examples of suitable dicarboxylic acids are succinic, glutaric, adipic, suberic, azelaic, sebacic, decanedicarboxylic, maleic, fumaric, phthalic, isophthalic and terephthalic acids. The dicarboxylic acids can be used both individually and in admixture. Instead of the dicarboxylic acids and the corresponding carboxylic acid derivatives, such as. As dicarboxylic acid esters of alcohols having 1 to 4 carbon atoms or dicarboxylic anhydrides are used. Preferably used dicarboxylic acid mixtures of succinic, glutaric and adipic acid in proportions of, for example, 20 to 35: 35 to 50: 20 to 32 parts by weight, and in particular adipic acid. Examples of dihydric and polyhydric alcohols, in particular alkanediols and dialkylene glycols, are: ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol , 1,10-decanediol, glycerine and trimethylolpropane. Preferably used are ethanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerol or mixtures of at least two of said alkanepolyols, in particular z. B. mixtures of 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol. Can also be used polyester polyols from lactones, eg. B. ε-caprolactone or hydroxycarboxylic acids, eg. B. ω-hydroxycaproic acid.

For the preparation of the polyester polyols b _22iii ), the organic, z. As aromatic and preferably aliphatic dicarboxylic acids and / or derivatives thereof and the polyhydric alcohols and / or alkylene glycols catalyst-free or preferably in the presence of Veresterungskatalysa factors, advantageously in an atmosphere of inert gases, such as. As nitrogen, helium, argon and others in the melt at temperatures of 150 to 250 ° C, preferably 180 to 220 ° C, optionally under ver reduced pressure to the desired acid number, which is advantageously less than 10, preferably less than 2 , polycondensed. According to a preferred embodiment, the esterification mixture at the abovementioned temperatures to an acid number of 80 to 30, preferably 40 to 30, under normal pressure and then under a pressure of less than 500 mbar, preferably 50 to 150 mbar, polycondensed. Suitable esterification catalysts are, for example, iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium 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, for the azeotropic distillation from the condensation water.

To prepare the polyesterpolyols b _22iii ), the organic dicarboxylic acids and / or their derivatives and the polyhydric alcohols are advantageously polycondensed in a molar ratio of 1: 1 to 1.8, preferably 1: 1.05 to 1.2. The polyesterpolyols obtained preferably have a functionality of 2 to 4, in particular 2 to 3, and a hydroxyl number of 240 to 30, preferably 180 to 40.

However, especially as polyhydroxyl compounds are used Polyoxyalkylene polyols prepared by known processes,  for example, by anionic polymerization with alkali metal hydroxides, such as Sodium or potassium hydroxide, or with alkali alcoholates, such as sodium methylate, sodium or potassium ethylate or potassium isopropylate, as a catalyst and with the addition of at least one starter molecule, 2 to 8, preferably contains 2 to 3 reactive hydrogen atoms bound, for Preparation of Polyoxyalkylene Polyols for Flexible PU Foams, and preferably contains 3 to 8 reactive hydrogen atoms bound to Preparation of Polyoxyalkylene Polyols for Semi-Hard and Hard PU Foams, or by cationic polymerization with Lewis acids, such as antimony pentachloride, borofluoride etherate and. a. or bleaching earth as Catalysts of one or more alkylene oxides having 2 to 4 Carbon atoms in the alkylene radical.

Suitable alkylene oxides are, for example, tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide and preferably ethylene oxide and 1,2-propylene oxide. The alkylene oxides can be used individually, alternating be used sequentially or as mixtures. As starter molecules For example: water, organic dicarboxylic acids, such as succinic, adipic, phthalic and terephthalic acid, alipha and aromatic, optionally N-mono-, N, N- and N, N'-dialkyl substituted diamines having 1 to 4 carbon atoms in the alkyl radical, such as optionally mono- and dialkyl-substituted ethylenediamine, diethylene triamine, triethylenetetramine, 1,3-propylenediamine, 1,3- or 1,4-butylenedi amine, 1,2-, 1,3-, 1,4-, 1,5- and 1,6-hexamethylenediamine, phenylenediamines, 2,3-, 3,4-, 2,4- and 2,6-toluenediamine and 4,4'-, 2,4'- and 2,2'-diamino diphenylmethane.

As starter molecules also come into consideration: alkanolamines, such as. B. Ethanolamine, N-methyl- and N-ethyl-ethanolamine, dialkanolamines, such as z. As diethanolamine, N-methyl and N-ethyldiethanolamine and trialkanol  amine, such as. As triethanolamine, and ammonia. Preferably used are polyhydric, especially dihydric to octahydric alcohols and / or Alkylene glycols such as. Ethanediol, 1,2-propanediol and 1,3-diethy glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trim thylolpropane, pentaerythritol, sorbitol and sucrose and mixtures of at least two polyhydric alcohols.

The polyoxyalkylene polyols, preferably polyoxypropylene and Polyoxypropylene-polyoxyethylene polyols have a functionality of 2 to 8 and hydroxyl numbers from 25 to 500, taking for flexible PU foam Polyoxyalkylene polyols with a functionality of 2 to 3 and a hydroxyl number of 30 to 80 and for semi-hard and hard PU foams Polyoxyalkylene polyols having a functionality of 3 to 8 and a hydroxyl value of 100 to 500 are preferably used and suitable polyoxytetramethylene glycols have a hydroxyl number of 30 to have about 280.

As polyoxyalkylene polyols are also polymer-modified Polyoxyalkylene polyols, preferably graft polyoxyalkylene polyols, in particular those based on styrene and / or acrylonitrile, which are replaced by In situ polymerization of acrylonitrile, styrene or, preferably, mixtures of styrene and acrylonitrile, e.g. In the weight ratio 90: 10 to 10: 90, preferably 70:30 to 30:70, suitably the aforementioned Polyoxyalkylenepolyols analogous to the details of the German patents 11 11 394, 12 22 669 (US 3 304 273, 3 383 351, 3523 093), 11 52 536 (GB 10 40 452) and 11 52 537 (GB 987618), as well as Polyoxyalkylen polyoldispersionen as the disperse phase, usually in an amount of 1 to 50% by weight, preferably 2 to 25% by weight, contained th: z. As polyureas, polyhydrazides, tertiary amino groups bound containing polyurethanes and / or melamine and the z. B. described  are described in EP-B 011 752 (US-A 4,304,708), US-A 4,374,209 and DE-A 32 31 497.

The polyoxyalkylene polyols can be used individually or in the form of mixtures be used. Furthermore, they can with the graft polyoxyalkylene polyols or polyester polyols and the hydroxyl-containing polyester amides, polyacetals and / or polycarbonates are mixed.

As hydroxyl-containing polyacetals come z. B. from glycols, such as diethylene glycol, triethylene glycol, 4,4'-dihydroxyethoxy-diphenyldime methylmethane, hexanediol and formaldehyde producible compounds in Question. Also by polymerization of cyclic acetals can be appropriate Produce polyacetals.

As hydroxyl-containing polycarbonates such come on known type, for example, by implementation of Diols, such as. As propanediol (1,3), butanediol (1,4) and / or hexane diol (1,6), diethylene glycol, triethylene glycol or tetraethylene glycol with Diaryl carbonates, e.g. As diphenyl carbonate, or phosgene are prepared can.

The polyester amides include, for. B. from polyvalent, saturated and / or unsaturated carboxylic acids or their anhydrides and polyhydric saturated and / or unsaturated aminoalcohols or Mixtures of polyhydric alcohols and amino alcohols and / or Polyamines obtained, predominantly linear condensates.

The isocyanate prepolymer mixtures prepared according to the invention are storage stable. When stored at room temperature and to the exclusion of Moisture, the levels of free isocyanate groups remain in the  Prepolymer mixtures unchanged. The prepared isocyanate prepoly Mer mixtures are particularly suitable for the production of poly urethane foams.

In the inventive method for producing compact or cellular, oligo- and / or polysaccharide-containing polyurethanes, become

• a) higher molecular weight compounds having at least two reactive What with hydrogen atoms
• b) bound urethane groups contained in di- and / or polyisocyanate sammensetzungen

implemented. This happens in the presence or absence of

• c) chain extenders and / or crosslinkers,
• d) propellants,
• e) catalysts and
• f) aids.

According to the invention, the di- and / or Polyisocyanatzusam compositions b) consist of
b₁) 0-99 wt .-% of at least one organic or organically modifi ed di- and / or polyisocyanate component and
b₂) 1 to 100 wt .-% of an isocyanate prepolymer mixture, as defined above, each based on the total weight of b). Preferably, the di- and / or polyisocyanate compositions contain b) 20-90 wt .-%, in particular 30 to 70 wt .-% di- and / or polyiso cyanatkomponente b₁) and 10-80 wt .-%, in particular 30 to 70th Wt .-%, isocyanate prepolymer mixture b₂), each based on the total weight of b).

As di- and / or polyisocyanate component b₁) are all Isocyana te as defined above for component b₂₁). Most 4,4'-methylenedi (phenylisocyanate) (MDI) is also preferred here.

In the process according to the invention for the preparation of polyurethanes, preference is given to the compounds a) having a functionality of from 2 to 8 and an amine or hydroxyl number of from 25 to 500 and being expediently selected from the group of the polyoxyalkylene polyamines and / or the Polyhydroxyl compounds (polyols), in particular the polyhydroxyl compounds, as defined above for the component b _22iii ) defi ned.

In the production of flexible PU foams can be used to modes fication of the mechanical properties of PU foams, z. B. the Hardness, the addition of chain extenders, crosslinking agents or optionally also mixtures thereof prove to be advantageous. at the production of rigid PU foams can usually on the Use of chain extenders and / or crosslinkers ver be canceled. As chain extenders c) difunctional Compounds, as crosslinking agent c) tri- and higher functional Verbin each having molecular weights less than 400, preferably from 62 to about 300 are used. As chain extender c) may be mentioned by way of example alkanediols, z. For example, those with 2 to 6 carbon atoms in the alkylene radical, such as. Ethane, 1,3-propane, 1,4-butane, 1,5-pentane and 1,6-hexanediol, and dialkylene glycols, such as. B. diethylene, Dipropylene and dibutylene glycol, and as crosslinking agent c) alkanola mine, z. For example, ethanolamine, dialkanolamine, z. B. diethanolamine, and Trialka nolamines, e.g. Triethanolamine and triisopropanolamine, and three and / or or higher alcohols, such as. As glycerol, trimethylolpropane and Pentaerythritol. Suitable chain extenders or crosslinkers are suitable  also the low molecular weight ethoxylation and / or propoxylation products, eg. For example, those having molecular weights up to about 400, the aforementioned polyhydric alcohols, alkylene glycols, alkanolamines and of aliphatic and / or aromatic diamines.

As chain extenders c) are preferably used Alkandio in particular butanediol-1,4 and / or 1,6-hexanediol, alkylene glycols, especially ethylene glycol and propylene glycol, and as crosslinking agents c) trihydric alcohols, in particular glycerol and trimethylolpropane, Dialkanolamines, especially diethanolamine, and trialkanolamines, especially triethanolamine.

The chain extenders and / or crosslinkers c), preferably be used for the production of flexible PU foams, can be used, for example, in amounts of from 2 to 60% by weight, preferably from 10 to 40 wt .-%, based on the weight of the higher molecular weight Compounds a) are used.

Suitable as blowing agent d) for the preparation of cellular polyurethanes are water and / or in liquid form at room temperature Gases and liquids, which compared to the compounds a) and the Isocyanates b), their mixtures or inventively prepared Isocyanate prepolymer mixtures are inert and boiling points below 50 ° C, in particular between -50 ° C and 30 ° C at atmospheric pressure aufwei and mixtures of gaseous and liquid propellants. at games of such preferably usable gases and liquids Alkanes, such as. As propane, n- and iso-butane, n- and iso-pentane, preferably example technical mixtures of n- and iso-pentane, and cycloalkanes, such as z. For example, cyclopentane, alkyl ethers, such as. For example, dimethyl ether, diethyl ether and Methyl isobutyl ether, carboxylic acid alkyl esters, such as. Methyl formate, and  halogenated hydrocarbons, such as. For example, dichlorofluoromethane, trifluoromethane than, 1,1-dichloro-1-fluoroethane, monochlorotrifluoroethane, monochlorodifluoroethene han, difluoroethane, dichlorotrifluoroethane, monochlorotetrafluoroethane, Pentafluoroethane, tetrafluoroethane and dichloromonofluoroethane. To Her position of the cellular polyurethanes, preferably PU foams In particular, water, linear and cyclic alkanes with 5 to 7 C-atoms and mixtures thereof. The exemplified Treib agents can be used singly or as mixtures. As a drive Medium should not be used chlorofluorocarbons, as they are damage the ozone layer.

Used in a mixture with liquids with boiling points below 50 ° C can also (cyclo) alkanes, such as. Hexane and cyclohexane and Carboxylic acid alkyl esters, such as. Ethyl formate, with boiling points above 50 ° C, if the propellant mixture expediently a boiling point below 38 ° C. The required amount of propellant or Depending on the type of propellant or the mixture Propellant mixture and the mixing ratios in a simple manner be determined experimentally. Usually, the propellants are in in an amount of 0.1 to 30 parts by weight, preferably 1 to 25 Parts by weight, based on 100 parts by weight of components a) to c), used.

Catalysts e) that can be used in PU production, are preferably compounds which are the reaction of the higher molecular weight Compounds a) with the isocyanates b) or according to the invention strongly accelerate produced isocyanate prepolymer mixtures. When Catalysts are suitable for. B. organic metal compounds, preferably organic tin compounds, such as tin (II) salts of organi rule carboxylic acids, eg. Tin (II) diacetate, tin (II) dioctoate, tin (II) diethylhexoate  and stannous dilaurate and the dialkyltin (IV) salts of organic carboxylic acids, eg. Dibutyltin diacetate, dibutyltin dilaurate, Dibutyltin maleate, dioctyltin diacetate, and dibutyltin dimercaptide and strongly basic amines, for example amidines, such as. For example, 2,3-dime thyl-3,4,5,6-tetrahydropyrimidine, tertiary amines, such as. Triethylamine, Tributylamine, dimethylbenzylamine, N-methyl, N-ethyl, N-cyclohexylmor pholine, dimorpholino-diethyl ether, N, N, N ', N'-tetramethylethylenediamine, N, N, N ', N'-tetramethylbutanediamine, N, N, N', N'-tetramethylhexanediamine-1,6, Di (4-N, N-dimethylaminocyclohexyl) methane, pentamethyldiethylenetriamine, Tetramethyldiaminoethyl ether, bis (dimethylaminopropyl) urea, Dimethylpiperazine, 1,2-dimethylimidazole, 1-azabicyclo [3.3.0] octane, Alkanolamine compounds, such as triethanolamine, triisopropanolamine, N-methyl- and N-ethyl-diethanolamine and dimethylethanolamine, Tris- (N, N-dialkylaminoalkyl) -s-hexahydrotriazines, especially Tris- (N, N-dimethylaminophenyl) -s-hexahydrotriazine, tetraalkylammonium hydroxides such as tetramethylammonium hydroxide and preferably 1,4-dia za [2.2.2] octane. Preferably, 0.001 to 5 are used Wt .-%, in particular 0.05 to 2 wt .-% catalyst or catalyst combination, based on the weight of component a).

The reaction mixture for the preparation of the compact or cellular Polyurethanes, preferably PU foams, may optionally also still aids f) are incorporated. Examples include surfactants, foam stabilizers, cell regulators, flame protectants, fillers, dyes, pigments, antistatic agents, hydrolysis protection medium, fungistatic and bacteriostatic substances.

As surface-active substances z. B. compounds, which help to homogenize the reaction mixtures serve and if appropriate also suitable, the cell structure of the  To regulate PU foams. Examples include emulsions such as the sodium salts of castor oil sulphates or of fatty acids, and salts of fatty acids with amines, e.g. As oil diethylamine, stearic acid diethanolamine, ricinoleic diethanolamine, salts of Sulfonic acids, e.g. As alkali or ammonium salts of dodecylbenzene or Dinaphthylmethanedisulfonic acid, and ricinoleic acid; Foam stabilizers, such as siloxane-oxalkylene copolymers and other organopolysiloxanes, ethoxylated alkylphenols, ethoxylated fatty alcohols, paraffin oils, castor oil or Ricinoleic acid esters, Turkish red oil and peanut oil and cell regulators, such as fumed silica, paraffins, fatty alcohols and dimethylpolysiloxanes. To improve the emulsifying effect, the cell structure and / or Stabili tion of the foam are also suitable oligomeric polyacrylates Polyoxyalkylene and Fluoralkanresten as side groups. The surfaces Active substances are usually used in amounts of 0.01 to 5 Parts by weight, based on 100 parts by weight of component a) applied.

Suitable flame retardants are, for example, diphenyl cresyl phosphate, Tricresyl phosphate, tris (2-chloroethyl) phosphate, tris (2-chloropropyl) phosphate, Tris (1,3-dichloropropyl) phosphate, tris (2,3-dibromopropyl) phosphate and tetra kis- (2-chloroethyl) ethylene diphosphate.

In addition to the said halogen-substituted phosphates can also inorganic flame retardants, such as. For example, alumina hydrate, Antimony trioxide, arsenic oxide, ammonium polyphosphate, expandable graphite and Calcium sulfate, or cyanuric acid derivatives, such as. As melamine, or Mischun from at least two flame retardants, such as. B. ammonium poly phosphates and melamine and / or expandable graphite, and optionally Starch for flame retardancy of the isocyanate prepolymer mixtures produced PU foams are used. In general, it has proved to be useful, 5 to 50 parts by weight, preferably 10 to  40 parts by weight of said flame retardants or mixtures for each 100 parts by weight of components a) to c) to use.

As fillers, in particular reinforcing fillers, are the known, customary organic and inorganic fillers and Understand reinforcing agents. Specific examples are: inorganic fillers such. B. silicate minerals, for example Phyllosilicates, such as antigorite, serpentine, hornblende, amphibole, chryso til, zeolites, talc; Metal oxides, such as. Kaolin, aluminas, Aluminum silicate, titanium oxides and iron oxides, metal salts such. Chalk, Barite and inorganic pigments, such as cadmium sulfide, zinc sulfide, as well as glass particles. As organic fillers are for example in Consider: carbon black, melamine, rosin, cyclopentadienyl resins and Graft polymers.

The inorganic and organic fillers can be used individually or as Mixtures are used and are the reaction mixture advantageously in amounts of from 0.5 to 50% by weight, preferably 1 to 10 wt .-%, based on the weight of components a) to c), a verleibt.

More details about the other common tools mentioned above f) are the specialist literature, for example the monograph of J.H. Saun ders and K.C. Fresh "High Polymers" Volume XVI, Polyurethanes, Part 1 and 2, Verlag Interscience Publishers 1962 and 1964, or the art Stoff-Handbuch, Polyurethane, Volume VII, Carl-Hanser-Verlag, Munich, Vienna, 1st and 2nd editions, 1966 and 1983.

The compact or cellular polyurethanes produced are in particular used for the production of polyurethane foams, for example  soft polyurethane foams, as used in the manufacture of furniture, eg. B. Furniture cushions, and automobile seats or mattresses use find. In addition, the polyurethanes can also be used to manufacture ment of rigid polyurethane foams, z. B. for the production of isola tion materials, such. B. in refrigerators as insulation foams, or also for the production of compact polyurethanes, eg. B. duromers, such as For example, in computer housings, window frames or integral foaming (eg steering wheels, shoe soles) find use. The from the molded parts according to the invention show better mechanical and application properties as molded parts Saccharide-free polyurethanes, in particular a reduced shrinkage as well as improved elongation and tear resistance.

The invention is illustrated by the following examples which represent preferred embodiments of the invention.

In the examples, all viscosities were angege at the respective temperature is measured with the rotational viscometer and the OH numbers were measured according to DIN 53240 by means of the anhydride method.

example

To assess the mechanical properties of starch-containing Polyurethane (PU) were produced PU test plates and their mecha niche strength measured. As a comparison served here a starch-free System.  

For the preparation of the PU test plates, the following isocyanate and Polyol components mixed together, wherein for the starch-containing System containing the polyol component starch solution.

For the preparation of the starch solution was partially degraded starch a DE value of 18 to 19, C-PUR 1915 from Cerestar, to 33 Wt .-% dissolved in glycerol. This gives a clear, slightly brownish Liquid with a viscosity of 94,800 mPas at 25 ° C or 8800 mPas at 50 ° C.

As the isocyanate component, a polyisocyanate mixture was used with a -N = C = O content of 23 wt .-%, by reaction of Monomor MDI and polypropylene glycol having a molecular weight of 500 had been presented.

The following polyol component was used (in parts by weight):
Strength-free system:

base polyol * 76.0 glycerin 20.0 25% solution of diazabicyclooctane in butanediol 0.78 dibutyltindilaurate 0.02 Silicone-based foam stabilizer (DC 193 from Dow Chemical) 0.20 cyclopentane 3.00

Starch-containing system:

base polyol * 71.0 starch solution 25.0 25% solution of diazabicyclooctane in butanediol 2.28 dibutyltindilaurate 0.02 47% solution of potassium acetate in ethylene glycol 0.50 Silicone-based foam stabilizer (DC 193 from Dow Chemical) 0.20 cyclopentane 3.00

As the base polyol * (base polyether polyol) became a trifunctional Propylene-ethylene oxide block polyetherol containing primary Hydroxyl end groups of <80%, a hydroxyl number of 35 mg KOH-g Polyol and a viscosity of 850 mPas at 25 ° C used.

The polyol and isocyanate components were prepared according to the procedure given in Table 1 and 2 indicated index intensively mixed together, wherein

Index = (mole [-N = C = O] / mole [OH]) × 100

ie index <100 corresponds to an excess of [-N = C = O];
Index <100 corresponds to an excess of [OH];
Index = 100 corresponds to an equivalent amount of [-N = C = O] and [OH];

The reaction mixture was used to determine the reaction times and of the free-foamed density in an open cup (1000 ml) and for determining the mechanical properties of the molded parts (PU test plates)  in a heated mold (mold temperature 50 ° C) with filled the dimensions 250 × 250 × 10 mm³ and react there gelas sen.

The moldings were after a demolding time of 20 minutes from the Taken form and before determining the mechanical properties stored for 24 hours at room temperature.

As reaction times, the start and the setting time were determined. In addition, the climb time was determined, this is the time from the beginning of the Stirring until the end of the foam rising process in the cup test, the Observation was made optically or by ultrasonic sensor.

The mechanical characteristics were determined as follows: Shrinkage, determined by the average reduction of the plates edge length in cm, Shore hardness according to Shore D according to DIN 53505 and Tensile tests (elongation and tear strength) according to HQP (Schuhsohlenmate rial).

The results are shown in Tables 1 and 2.  

Table 1

PU test plates - comparative test (starch-free system)

Table 2

PU test plates - starchy system

As can be seen from Tables 1 and 2, the test plates showed the starch-containing polyurethane reduced shrinkage as well increased hardness and tear resistance and thus better mechanical properties than the test plates made of the non-starch-containing polyurethane.

Claims (19)

1. isocyanate prepolymer mixture containing urethane groups and reactive isocyanate groups bonded, characterized in that it has a -N = C = O content of 2.5 to 30 wt .-%, based on the total weight of the isocyanate prepolymer Mixture, and that it is available from the implementation of

• b₂₁) with at least one di- and / or polyisocyanate
• b₂₂) of a solution or emulsion containing
  • b _22i ) at least one oligosaccharide and / or polysaccharide and
  • b _22ii ) at least one non-aqueous, compared to the di- and / or polyisocyanate b₂₁) reactive solvent and optionally
  • b _22iii ) at least one polyhydroxyl compound.

2. isocyanate prepolymer mixture according to claim 1, characterized in that the solution or emulsion contains b₂₂)

• b _22i ) from 99 to 50% by weight of at least one oligosaccharide and / or poly saccharide,
• b _22ii ) 1 to 50 wt .-% of at least one non-aqueous, compared to the isocyanate b _22i ) reactive solvent and
• b _22iii ) 0 to 50 wt .-% of at least one polyhydroxyl compound, based on the total weight of the solution or emulsion b₂₂).

3. isocyanate prepolymer mixture according to claim 1 or 2, gekenn characterized by a -N = C = O content of 5 to 25 wt .-%, based on the total weight of the isocyanate prepolymer mixture. 4. isocyanate prepolymer mixture according to one of claims 1 to 3, characterized in that it is obtainable from the reaction from 20 to 90% by weight of di- and / or polyisocyanate b₂₁) and from 10 to 80 wt .-% solution or emulsion b₂₂), based on the total Weight of the isocyanate prepolymer mixture. 5. isocyanate prepolymer mixture according to any one of the preceding claims, characterized in that the saccharide b _22i ) is a partially degraded natural polysaccharide, in particular an oligosaccharide having dextrose equivalent _values of 5 to 50. 6. isocyanate prepolymer mixture according to any one of the preceding claims, characterized in that the solvent b _22ii ) is a polar higher polyol, in particular glycerol or a glycol. 7. isocyanate prepolymer mixture according to any one of claims 1 to 5, characterized in that the solvent b _22ii ) is a C₂- to C₅-alkanolamine or C₁- to C₅-alkyl-C₂- to C₅-alkanolamine. 8. isocyanate prepolymer mixture according to any one of the preceding claims, characterized in that the Polyhydroxylverbindun gene b _22iii ) have a functionality of 2 to 8 and a hydroxyl number of 25 to 500 and preferably consist of Polyhydroxylverbindun conditions, which are in particular selected from polythioether Polyols, polyester amides, hydroxyl-containing polyacetals, hydroxyl-containing aliphatic polycarbonates, polyester polyols, polymer-modified polyether polyols, preferably polyether polyols and mixtures Mi from at least two of said Polyhydroxylverbindun conditions. 9. isocyanate prepolymer mixture according to one of the preceding Claims, characterized in that the isocyanate b₂₁) 4,4'-methylenedi (phenyl isocyanate) (MDI) is. 10. Use of the isocyanate prepolymer mixture according to one of Isocyanate prepolymer blends directed claims, in which Production of polyurethane. 11. A process for preparing an isocyanate prepolymer mixture according to one of the directed to isocyanate prepolymer blends Ansprü che, characterized by the implementation of in the isocyanate prepolymer mixtures directed claims defined di- and / or Polyisocyanate b₂₁) with the solution or emulsion b₂₂). 12. A process for the preparation of compact or cellular Polyuretha NEN, preferably polyurethane foams, by reacting

• a) higher molecular weight compounds having at least two reactive hydrogen atoms with
• b) urethane groups bonded di- and / or polyiso cyanatzusammensetzungen
  in the presence or absence of
• c) chain extenders and / or crosslinkers,
• d) propellants,
• e) catalysts and
• f) aids,

characterized in that the di- and / or polyisocyanate compositions b)
b₁) 0 to 99 wt .-% of at least one organic and / or orga nisch modified di- and / or polyisocyanate component and
b₂) 1 to 100% by weight of an isocyanate prepolymer mixture according to one of the claims directed to isocyanate prepolymer mixtures,
based on the total weight of b). 13. The method according to claim 12, characterized in that the di- and / or Polyisocyanate compositions b) 20 to 90 wt .-% di- and / or Polyisocyanate component b₁) and 10 to 80 wt .-% iso cyanate-prepolymer mixture b₂), based on the total weight of b). 14. The method according to claim 12 or 13, characterized in that the higher molecular weight compounds a) polyhydroxyl compounds and / or polyoxyalkylene polyamines having a functionality of 2 to 8 and a hydroxyl number or amine number of 25 to 500 are. 15. The method according to any one of claims 12 to 14, characterized gekenn records that as propellant d) water, linear and cyclic Alkanes having 3 to 7 carbon atoms or mixtures thereof used. 16. Polyurethane obtainable according to one of the claims 12 to 15 defined procedures.   17. Use of polyurethane according to claim 16, for the preparation of Moldings. 18. molded parts, made of polyurethane according to claim 16.