DE19545550A1 - Isocyanate prepolymer mixt. based on poly:ol mixt. contg. renewable lignin - Google Patents

Abstract

NCO-prepolymer mixt. (I) contg. urethane gps.and 2.5-30 wt.% reactive NCO is claimed. (I) is obtd. by reacting (a) 4,4'-, 2,4'- and 2,2'-di-phenylmethane diisocyanate, an isomer mixt. of 4,4'- and 2,4'-and opt. 2,2'-di-phenylmethane diisocyanate or a mixt. of diphenylmethane diisocyanates and poly-phenyl-polyphenylene polyisocyanates with (b) a suspension contg. (b-1) polyoxypropylene glycol(s) (IIA) and/or polyoxypropylene-polyoxyethylene glycol(s) (IIB) with a mol.wt. of 400-6000, pref. 1000-3000 and (b-ii) lignin. Also claimed are methods for producing (1) (I) by reacting the specified organic polyisocyanates and suspension; and (2) compact or cellular polyurethanes, pref. PU foam.

Description

The present invention relates to lignin-containing isocyanate prepo lymer mixtures. The invention also relates to methods for the manufacture position of such isocyanate prepolymer mixtures. After all, is counter the invention also relates to the use of the isocyanate prepolymer Mixtures according to the invention for the production of polyurethanes (PU), in particular of foamed moldings based on polyurethane, and procedures therefor

Lignin and tannin are known as starter molecules Polyoxyalkylene polyols. According to US-A-3,546,199 and US-A- 3,654,194 can be lignin or tannin in the presence or absence of Solvents with alkylene oxides, such as. B. 1,2-propylene oxide, at Tempe Raturations from 20 to 250 ° C and optionally increased pressure alkoxylated will. The polyoxyalkylene polyols produced have hydroxyl numbers in the range from 50 to 1000, preferably from 200 to 800, and are suitable itself by reaction with organic polyisocyanates for the production from flexible to hard PU foams.

EP-A-0 342 781 describes the use of lignin in the PU-Her position. Solutions of lignin in tetrahydrofuran (THF) or polyoxy Ethylene glycol (PEG) are mixed with diphenylmethane diisocyanates (MDI)  60 ° C or reacted at room temperature. The one from it films obtained have good mechanical strength, foams good elasticity according to the publication. It will no comparative examples given without lignin. The lignin forms the Hard phase, the PEG the soft phase.

Lignin can also be dissolved in and from polyoxyethylene glycols (PEG) Solution are implemented with isocyanates to polyurethane parts, as described in US-A-3,519,581. The lignin is used in a polyoxyethylene glycol (PEG) or a mixture of PEG and Polyoxypropylene glycol (PPG) dissolved and if necessary at temperatures treated above 100 ° C to esterify the carboxyl groups of the lignin. The lignin-polyoxyalkylene-glycol solutions obtained become more advantageous Allow to cool to a temperature below 100 ° C before using the polyisocyanates to form polyurethanes for reaction be brought. The reaction always takes place in the presence of an upper surface active connection instead.

US-A-3,577,358 describes the lignin for reaction either in PEG or to dissolve in dioxane. The curing takes place during several Hours at room temperature or at an elevated temperature (<80 ° C). Polyurethane insulation is done by removing the solvent. Lignin and isocyanate react when mixed at 120 ° C. The IR spectrum shows that all OH and -N = C = O groups react are.

The direct use of lignin in polyurethane systems however, in addition to the lack of reactivity of the solid but also dissolved Lignins, e.g. B. lignin dissolved in tetrahydrofuran or dioxane Another isocyanate under the conditions of polyurethane production Number of other disadvantages in the way. Influences their high salinity  the sensitive catalysis of the PU systems is very strong, especially if the lignins are used as a solution and not as a solid. Lignins are mainly used industrially as "thickeners" they also increase viscosity in higher concentrations water-containing polyetherol components. It is also often a mistake The inertness of the lignin with other PU polyol components can be observed ten, which has the consequence that the very fine lignin particles after the preparation of the polyol mixture coalesce so that it no longer is processable. Some of the lignin OH groups are phenolic in nature, so that the polyurethane bonds obtained from them are thermolabile. For the reasons listed, lignin polyurethanes could be used in their Processing and product properties do not satisfy. in the general are by incorporating the lignin itself into polyurethane foams deteriorate the mechanical properties. To at all Obtaining PU parts with good properties is often a special factor Niert lignine used or lignins, which according to a special Processes have been obtained (e.g. organosolvlignins).

Common disadvantages of lignin in PU production are missing Reactivity, lack of incorporation of the lignin in the PU matrix. Lignin solution gene are usually highly viscous and with organic polyisocyanates difficult to mix; in addition, the foams have poor mechanical properties Properties. The high molecular weight portions of the lignin are removed separates and the reaction is carried out in solution, PU parts are obtained, for which a number of advantages are reported. E.g. will be a low one rer index required, cf. CA-A-2,052,487. With Kraft lignin itself it can PU polyaddition reaction not carried out in a PEG solution will. The molecular weight of the lignin and the viscosity of the lignin solution in PEG are too high, the miscibility with the isocyanate com component is too bad. With special modified lignin, e.g. B. Such with a low molecular weight of 300 to 2000 and better  Solubility, become more homogeneous foams with good mechanical properties preserved. It can be a one-shot or a prepolymer driving style. In the latter case, lignin / polyols / Isocyanates made a prepolymer, which was then cast into films or by mixing with water / catalysts / stabilizers can also be foamed.

In order to ver with the direct processing of the lignin listed To overcome the associated difficulties, the oxyalkylation of Lignins suggested. However, this is expensive. Generally find lignins or lignin derivatives due to the (processing) difficulty listed are currently not used on an industrial scale for the production of Polyurethanes. US-A-3,546,199 and US-A-3,654,194 describe how solid, powder or in reactive or unreactive solutions medium dissolved lignin without catalyst and under KOH / aniline catalysis Lignin polyetherols can be implemented. From the OH numbers of the Polyols obtained are back calculated the OH numbers of the lignins. They are approx. 600 to 1300. Tannin can be used as well Lignin. The OH numbers of the lignin polyether polyols are 50 to 1000.

The object of the present invention is to process isocyanate To provide prepolymer blends. Another task of the Erfin is to specify such isocyanate prepolymer mixtures, those in their further processing into polyurethane products, in particular to polyurethane foams, products that provide improved physical Properties, especially what is elongation at break, tensile strength and / or Tear resistance, have. Another task of the present invention is the creation of manufacturing processes such isocyanate prepolymer mixtures and methods for Manufacture of polyurethanes with the improved mechanical properties create.  

This problem is solved by isocyanate prepolymer mixtures, such as they are defined in the claims. The method according to the invention for the production of such polyisocyanate prepolymer mixtures and Use for the production of polyurethanes and polyurethane products and methods therefor are also defined in the claims. Before Preferred embodiments of the invention result from the following Description and the subclaims.

According to the invention, a natural substance, ie one, is advantageously used renewable polyhydroxyl compound used.

According to the invention, the synthetic materials are advantageously produced th polyhydroxyl compounds wholly or at least partially by lignin substituted as a hydroxyl group-containing natural product. The use this renewable hydroxyl-containing natural product no complex technical syntheses. It is also advantageous that in other areas as waste product lignin, if necessary after minor technical treatment and / or cleaning can be used for technical recycling. By ver According to the invention, novel starting materials can use polyisocyanate polyaddition products with different mechanical properties are produced, which in turn he new uses shut down.

The isocyanate prepolymer provided according to the invention Mixtures containing urethane groups and reactive isocyanate groups contain bound, arise from the implementation

• b1) at least one organic polyisocyanate on diphenylmethane diisocyanate base with
• b2) at least one polyhydroxyl component.

According to the invention, the polyhydroxyl component consists at least partially contained from a suspension of lignin in an oxypropylene group the polyoxyalkylene glycol. The isocyanate prepolymer according to the invention Mixture is characterized in that it has an NCO content of 2.5 up to 30 wt .-%, based on the total weight of the isocyanate prepoly mer mixture, have and are obtainable by reaction of

• b1) 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate, an isomeric amount mix of 4,4'- and 2,4'- or 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates or a mixture of diphenylmethane diisocyanates and polyphenyl polymethylene polyisocyanates
• b2) a suspension that contains
  • b2i) at least one polyoxyalkylene glycol with a molecular weight of 400 to 6000, preferably 1000 to 3000, selected from the group of polyoxypropylene glycols, polyoxypropylene-polyoxyethylene glycols and mixtures thereof, and
  • b2ii) lignin.

The ratio of lignin to hydroxyl groups is more Compound preferably so that 1 to 70 wt .-% lignin and 99 to 30% by weight of polyoxypropylene and / or polyoxypropylene-polyoxyethylene glycol-containing polyhydroxyl component (b2) together 100% by weight form the suspension. The lignin suspension preferably consists of 70 up to 30% by weight, in particular 60 to 50% by weight, of the polyoxypropylene polyoxyethylene glycols and / or in particular a polyoxypropylene gly kols, while the amount of lignin 30 to 70 wt .-%, in particular 40 to 50% by weight of the suspension.

The lignin suspension is preferably reacted with the Polyisocyanate without surfactants.  

The lignins used are preferably those that are not special have undergone chemical treatment for their further processing are. Kraft lignins are particularly preferred. Such lignins have advantageously an acid number of less than 10.

The preferred suspending agents for the lignin are polyoxypropy len-glycols with a molecular weight of 1000 to 3000.

The isocyanate prepolymer mixture is preferably a fluid Ge mixed with a -N = C = O content of 5 to 25 wt .-%, based on the Isocyanate prepolymer mixture. The most preferred isocyanate prep lymer mixture has an -N = C = O content of 9 to 15 wt .-%.

In the process according to the invention for producing the isocyanate Prepolymer blends include the components listed above Formation of the isocyanate-prepolymer mixture reacted with one another. The Lignin can be at least partially superficial with the hydroxyl groups Polyoxypropylene and / or polyoxypropylene-polyoxyethylene glycols as well optionally further polyhydroxyl compounds of polyhydroxylcom component (b2) reacted with esterification and thus chemically attached to it be bound. The chemical incorporation of lignin into the isocyanate Prepolymer mixture is carried out via the hydroxyl on the lignin Groups, namely from the suspension in reaction with the Isocyanate groups of the polyisocyanate component.

By including the lignin in the isocyanate prepolymer mixture NEN any other higher molecular weight Ver for polyurethane production bonds with at least two reactive hydrogen atoms are used will.  

Because of their viscosity and their suitability for prepolymer production it is easily possible to use lignin as a solid in polyoxypropylene-poly suspending oxyethylene glycols, preferably polypropylene glycols, remove the water adhering to the lignin (approx. 5% by weight) and so obtained anhydrous lignin suspension with isocyanates to lignin-containing Implement prepolymers.

By suspending in polyoxypropylene-polyoxyethylene glycols and / or polyoxypropylene glycols, it is easily possible up to about 70% by weight of lignin in the suspension and up to about 30 % By weight of lignin is introduced into the isocyanate prepolymer mixture. The Viscosity of the isocyanate prepolymer mixtures according to the invention despite the high lignin content low and these are easy to process.

The lignin-containing isocyanate prepolymer mixtures based on Lignin suspensions are stable on storage. Even after standing for a long time Room temperature is essentially viscosity and -N = C = O content unchanged.

Using the lignin-containing isocyanate according to the invention Prepolymer blends can be polyurethane parts without processing create difficulties. The mechanical properties of the obtained Parts are good. Unmodified lignins, e.g. B. standard Kraft lignin, Standard organosolvlignins or isolated by other digestion methods Lignins can be used and are among those of the invention Conditions can be easily processed into high-quality polyurethanes.

In the inventive method for producing compact or cellular polyurethanes, preferably PU foams

• a) High molecular weight compounds with at least two reactive What Atmospheric atoms, preferably polyhydroxyl compounds, with  
• b) liquid polyisocyanate together containing urethane groups settings

implemented. This happens in the presence or absence of

• c) chain extenders and / or crosslinking agents,
• d) blowing agents,
• e) catalysts and
• f) aids.

According to the invention, there is the polyisocyanate composition (b) at least partially from an isocyanate prepolymer mixture, as they was defined above.

In the process according to the invention for the production of Polyurethanes that the higher molecular weight compounds (a) have a funk tionality from 2 to 8 and an amine or hydroxyl number from 25 to 500 own and are expediently selected from the group of Polyoxyalkylene polyamines and / or the polyhydroxyl compounds, ins in particular the polyhydroxyl compounds with a functionality of 2 to 8 and a hydroxyl number of 25 to 500, which in turn is preferred are selected from the group of polythioether polyols, polyesteramides, hydroxyl group-containing polyacetals, hydroxyl group-containing aliphatic Polycarbonates, polyester-polyols, polymer-modified polyether-polyols, preferably polyether polyols and mixtures of at least two of the mentioned polyhydroxy compounds.

Suitable higher molecular weight polyhydroxyl compounds as described in (a) are used, as has already been explained, more appropriately have a functionality of 2 to 8 and a hydroxyl number of 25 to 500, preferred for the production of flexible PU foams Polyhydroxyl compounds with a functionality of preferably 2 to 3 and a hydroxyl number of preferably 30 to 80 and for the manufacture  hard PU foams, preferably polyhydroxyl compounds with a functionality of preferably 3 to 8 and in particular 3 to 6 and a hydroxyl number of preferably 100 to 500 suitably find application. Preferred polyhydroxyl compounds are linear and / or branched polyester polyols and in particular linear and / or branched polyoxyalkylene polyols used, wherein polyhydrox yl compounds from renewable natural substances and / or chemically modified renewable natural substances are particularly preferred. Also suitable as lignin-free polyhydroxyl compounds (a) polymer modified polyoxyalkylene polyols, polyoxyalkylene polyol dispersion and other hydroxyl-containing polymers and polycondensates the aforementioned functionalities and hydroxyl numbers, for example Polyester amides, polyacetals and / or polycarbonates, especially those made from diphenyl carbonate and hexanediol-1,6 by transesterification are, or mixtures of at least two of the higher molecular weight mentioned laren polyhydroxyl compounds (a).

Suitable polyester polyols can, for example, from organic Dicarboxylic acids with 2 to 12 carbon atoms, preferably aliphati Dicarboxylic acids with 4 to 6 carbon atoms and polyvalent Alcohols, preferably alkane diols having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms, dialkylene glycols and / or Alkanetriols with 3 to 6 carbon atoms can be produced. As Dicarboxylic acids come into consideration, for example: succinic acid, Glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decandi carboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and Terephthalic acid. The dicarboxylic acids can be used both individually and can also be used in a mixture. Instead of the free dicarboxylic acids can also the corresponding carboxylic acid derivatives, such as. B. Dicar bonic acid esters of alcohols with 1 to 4 carbon atoms or Dicar bonic anhydrides can be used. Preferably used  Dicarboxylic acid mixtures of succinic, glutaric and adipic acids in Ratios of amounts of, for example, 20 to 35: 35 to 50: 20 to 32 Parts by weight, and in particular adipic acid. Examples of two and polyhydric alcohols, especially 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, glyce rin and trimethylolpropane. Ethanediol is preferably used, Diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin or Mixtures of at least two of the alkane polyols mentioned, in particular re z. B. Mixtures of 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol. Polyester polyols made from lactones, e.g. B. ε-caprolactone or hydroxycarboxylic acids, e.g. B. ω-hydroxycaproic acid.

To produce the polyester polyols, the organic, for. B. aromatic and preferably aliphatic dicarboxylic acids and / or their derivatives and the polyhydric alcohols and / or alkylene glycols catalyst-free or preferably in the presence of Esterification catalysts, advantageously in an atmosphere Inert gases, such as B. nitrogen, helium, argon and. a. in the melt at Temperatures of 150 to 250 ° C, preferably 180 to 220 ° C, against if necessary under reduced pressure up to the desired acid number, which is advantageously less than 10, preferably less than 2, be polycondensed. According to a preferred embodiment the esterification mixture at the above temperatures up to an acid number of 80 to 30, preferably 40 to 30, below normal pressure and then under a pressure of less than 500 mbar, preferably 50 to 150 mbar, polycondensed. As an esterification catalyst gates come for example iron, cadmium, cobalt, lead, zinc, Antimony, magnesium, titanium and tin catalysts in the form of metal len, metal oxides or metal salts into consideration. The polycondensation can also be used in the liquid phase in the presence of  and / or entraining agents, such as. As benzene, toluene, xylene or chlorobene zol, carried out for azeotropic distillation of the condensation water will.

Organic dicarbonates are used to produce the polyester polyols acids and / or their derivatives and the polyhydric alcohols partially in a molar ratio of 1: 1 to 1.8, preferably 1: 1.05 to 1,2, polycondensed.

The polyester polyols obtained preferably have a functionality from 2 to 4, in particular 2 to 3, and a hydroxyl number from 240 to 30, preferably 180 to 40.

However, they are used in particular as polyhydroxyl compounds Polyoxyalkylene polyols, which are 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 Kataly catalysts and with the addition of at least one starter molecule which contains 2 to 8, preferably contains 2 to 3 reactive hydrogen atoms bound, for Production of polyoxyl kylene polyols for flexible PU foams, and preferably contains 3 to 8 reactive hydrogen atoms bound, for Manufacture of polyoxyalkylene polyols for semi-hard and hard PU Foams, or by cationic polymerization with Lewis acids, such as antimony pentachloride, boron fluoride etherate and the like. a. or bleaching earth as Catalysts of one or more alkylene oxides with 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, alternately  can be used in succession or as mixtures. As starter molecules For example, water, organic dicarboxylic acids, such as succinic acid, adipic acid, phthalic acid and terephthalic acid, alipha tables and aromatic, optionally N-mono-, N, N- and N, N'-dialkyl- substituted diamines with 1 to 4 carbon atoms in the alkyl radical, such as optionally mono- and dialkyl-substituted ethylenediamine, diethylene triamine, triethylene tetramine, 1,3-propylene diamine, 1,3- or 1,4-butylene diamine 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.

Other suitable starter molecules are: alkanolamines, such as, for. B. Ethanolamine, N-methyl and N-ethylethanolamine, dialkanolamines, such as e.g. B. diethanolamine, N-methyl and N-ethyldiethanolamine and trialkanol amines such as B. triethanolamine, and ammonia. Preferably used polyvalent, in particular two to eight, alcohols and / or alkylene glycols such as. B. Ethanediol, 1,2-propanediol and 1,3, Diethy lenglycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerin, trime thylolpropane, pentaerythritol, sorbitol and sucrose and mixtures of at least 2 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, wherein, as already stated was, for flexible PU foams polyoxyalkylene polyols with a Functionality from 2 to 3 and a hydroxyl number from 30 to 80 and for semi-hard and hard PU foams polyoxyalkylene polyols with a Functionality from 3 to 8 and a hydroxyl number from 100 to 500 are preferably used and suitable polyoxytetramethylene glycols have a hydroxyl number from 30 to about 280.  

Polymer-modified polyols are also suitable as polyoxyalkylene polyols Polyoxyalkylene polyols, preferably graft polyoxyalkylene polyols, especially those based on styrene and / or acrylonitrile, which are In-situ polymerization of acrylonitrile, styrene or preferably mixtures made of styrene and acrylonitrile, e.g. B. in a weight ratio of 90:10 to 10:90, preferably 70:30 to 30:70, suitably the aforementioned Polyoxyalkylene polyols analogous to the information in the German patent specifications 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) are produced as well Polyoxyalkylene polyol dispersions, which as a disperse phase, usually in an amount of 1 to 50% by weight, preferably 2 to 25% by weight ten: z. B. polyureas, polyhydrazides, tert-amino groups 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, like the polyester polyols used individually or in the form of mixtures. Can also them with the graft polyoxyalkylene polyols or polyester polyols as well the hydroxyl-containing polyester amides, polyacetals and / or Polycarbonates are mixed.

As polyacetals containing hydroxyl groups such. B. from glycols, such as diethylene glycol, triethylene glycol, 4,4'-dihydroxyethoxy-diphenyl-di Compounds which can be prepared from methyl methane, hexanediol and formaldehyde in question. The polymerization of cyclic acetals can also be used produce your own polyacetals.

Polycarbonates containing hydroxyl groups are those of known type into consideration, for example by implementing Diols such as B. propanediol (1,3), butanediol (1,4) and / or hexane  with diol- (1,6), diethylene glycol, triethylene glycol or tetraethylene glycol Diaryl carbonates, e.g. B. diphenyl carbonate, or phosgene can.

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

The higher molecular weight polyhydroxyl compounds (a) can, depending on Purpose of the isocyanate prepolymer mixtures (b) in whole or preferably partly by low molecular chain extension and / or crosslinking agents are replaced. In the manufacture of Flexible PU foams can be used to modify the mechanical Properties of the PU foams, e.g. B. the hardness, the addition of Chain extenders, crosslinking agents or optionally also Mixtures of these prove to be advantageous. In the manufacture of Rigid PU foams can usually be limited to the use of Chain extenders and / or crosslinking agents are dispensed with. As Chain extenders can bifunctional compounds, as Vernet tri and higher functional compounds each with molecule Lar weights less than 400, preferably from 62 to about 300 be used. Exemplified as a chain extender be alkanediols, e.g. B. those with 2 to 6 carbon atoms in the alkylene rest, such as B. ethane, 1,3-propane, 1,4-butane, 1,5-pentane and 1,6-hexane diol, and dialkylene glycols, such as. B. diethylene, dipropylene and dibuty lenglycol, and as a crosslinking agent alkanolamines, e.g. B. ethanolamine, Dialkanolamine, e.g. B. diethanolamine, and trialkanolamines, e.g. B. Triethanola min and triisopropanolamine, and trihydric and / or higher alcohols, such as B. glycerol, trimethylolpropane and pentaerythritol. As chain ver  The lower molecules are also suitable as extenders or crosslinking agents Ren ethoxylation and / or propoxylation products, e.g. B. those with Molecular weights up to about 400 of the aforementioned multivalent Alcohols, alkylene glycols, alkanolamines and aliphatic and / or aromatic diamines.

Preferred chain extenders are alkanediols, in particular 1,4-butanediol and / or 1,6-hexanediol, alkylene glycols, especially ethylene glycol and propylene glycol, and as a crosslinking agent trihydric alcohols, especially glycerin and trimethylolpropane, Dialkanolamines, especially diethanolamine, and trialkanolamines, especially triethanolamine.

The chain extender and / or crosslinking agent (c), the preferred wise used for the production of flexible PU foams the, for example in amounts of 2 to 60 wt .-%, preferred example, from 10 to 40 wt .-%, based on the weight of the higher molecular weight laren compounds (a) are used.

In a mixture with the isocyanate prepolymer mixtures according to the invention (b) further polyisocyanates can be used to produce the PU be applied. Examples include: Alkylenendiisocya nate with 4 to 12 carbon atoms in the alkylene radical, such as. B. 1,12-Thu decane diisocyanate, 2-ethyl-tetramethylene diisocyanate-1,4, 2-methyl-penta methylene-diisocyanate-1,5, 2-ethyl-2-butyl-pentamethylene-diisocyanate-1,5, Tetramethylene diisocyanate 1,4 and preferably hexamethylene diisocya nat-1.6; cycloaliphatic diisocyanates, such as. B. Cyclohexane-1,3- and 1,4-diisocyanate and any mixtures of these isomers, 1-isocyanato 3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorone diisocyanate), 2,4- and 2,6-hexahydrotoluylene diisocyanate and the corresponding isomers mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane diisocyanate and the  corresponding mixtures of isomers, and preferably aromatic di- and Polyisocyanates such as B. 2,4- and 2,6-tolylene diisocyanate and the ent speaking isomer mixtures, 4,4'-, 2,4'- and 2,2'-diphenylmethane-dii socyanate and the corresponding isomer mixtures, mixtures of 4,4′- and 2,4'-diphenylmethane diisocyanates, polyphenyl polymethylene polyisocya nate, mixtures of 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates (raw MDI) and mixtures from crude MDI and tolylene diisocyanates. The organic di and Polyisocyanates can be used individually or in the form of their mixtures will.

Mixtures have proven to be excellent as organic polyisocyanates from diphenylmethane diisocyanates and polyphenyl polymethylene polyisocya naten, preferably those with a diphenylmethane diisocyanate content of at least 35% by weight, e.g. B. from 45 to 95 wt .-% and in particular from 48 to 60% by weight, so that such crude MDI compositions are particularly preferably used.

Suitable as blowing agent (d) for the production of cellular polyurethanes are water and / or present in liquid form at room temperature Gases and liquids, which are compared to the liquid Isocyanate-prepolymer mixtures are inert and boiling points below 50 ° C, in particular between -50 ° C and 30 ° C at atmospheric pressure sen, as well as mixtures of gaseous and liquid blowing agents. At games of such preferably usable gases and liquids Alkanes such as e.g. B. propane, n- and iso-butane, n- and iso-pentane, preferred as technical mixtures of n- and iso-pentane, and cycloalkanes, such as e.g. B. cyclopentane, alkyl ethers such as. B. dimethyl ether; Diethyl ether and Methyl isobutyl ether, carboxylic acid alkyl esters, such as. B. methyl formate, and halogenated hydrocarbons such as B. dichlorofluoromethane, trifluorme than, 1,1-dichloro-1-fluoroethane, monochlorotrifluoroethane, monochlorodifluoret  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 carbon atoms and mixtures thereof.

The blowing agents mentioned by way of example can be used individually or as a mixture gene can be used. Not to be used as a blowing agent Chlorofluorocarbons that damage the ozone layer.

Used in a mixture with liquids with boiling points below 50 ° C can also be (cyclo) alkanes, such as. B. hexane and cyclohexane and Carboxylic acid alkyl esters, such as. B. ethyl formate, with boiling points above 50 ° C, if the blowing agent mixture expediently has a boiling point below 38 ° C. The required amount of blowing agent or -mixing can depend on the type of blowing agent or the Blowing agent mixture and the mixing ratios in a simple manner can be determined experimentally. The blowing agents are usually in an amount of 0.1 to 30 parts by weight, preferably from 1 to 25 Parts by weight, based on 100 parts by weight of components a-c, ver turns.

Catalysts (s) that can be used in PU production, are preferably compounds that react the hydroxyl groups containing component (a) with the isocyanate according to the invention Prepolymer mixtures (b) or the mixtures of isocyanate prepoly mer mixtures (b) and other organic polyisocyanates strong accelerate. Suitable catalysts are, for. B. organic Metal compounds, preferably organic tin compounds, such as Tin (II) salts of organic carboxylic acids, e.g. B. tin (II) diacetate, Tin (II) dioctoate, tin (II) diethylhexoate and tin (II) dilaurate and the  Dialkyltin (IV) salts of organic carboxylic acids, e.g. B. Dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, dioctyltin diacetate, and Dibutyltin dimercaptide and strongly basic amines, for example amidines, such as B. 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tertiary amines such as. B. Triethylamine, tributylamine, dimethylbenzylamine, N-methyl, N-ethyl, N-cyclohexylmorpholine, dimorpholino-diethyl ether, N, N, N ′, N′-tetramethy ethylenediamine, N, N, N ', N'-tetramethylbutanediamine, N, N, N', N'-tetramethyl hexanediamine-1,6, di- (4-N, N-dimethylaminocyclohexyl) methane, pentamethyl diethylenetriamine, tetramethyldiaminoethyl ether, bis (dimethylaminopro pyl) urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-azabicy clo [3.3.0] octane, alkanolamine compounds such as triethanolamine, triisopro panolamine, N-methyl and N-ethyl-diethanolamine and dimethylethanola min, tris- (N, N-dialkylaminoalkyl) -s-hexahydrotriazine, in particular Tris- (N, N-dimethylaminopropyl) -s-hexahydrotriazine, tetraalkylammonium hydroxides such as tetramethylammonium hydroxide and preferably 1,4-diaza bicyclo [2.2.2] octane. 0.001 to 5% by weight are preferably used, in particular 0.05 to 2% by weight of catalyst or catalyst combination, based on the weight of component (a).

The reaction mixture to make the compact or cellular Polyurethanes, preferably PU foams, can optionally also aids (f) are still incorporated. For example surface-active substances, foam stabilizers, cell regulators, flame protective agents, fillers, dyes, pigments, antistatic agents, hydrolysis protection medium, fungistatic and bacteriostatic substances.

As surface-active substances such. B. connections into consideration which support the homogenization of the isocyanate prepolymer Mixtures serve and, if appropriate, are also suitable, the cell structure regulate the PU foams. For example Emulsifiers, such as the sodium salts of castor oil sulfates or of fat  acids, and salts of fatty acids with amines, e.g. B. oleic acid diethyla min, stearic acid diethanolamine, ricinoleic acid diethanolamine, salts of Sulfonic acids, e.g. B. alkali or ammonium salts of dodecylbenzene or Dinaphthylmethane disulfonic 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 stabilizers sation of the foam are also suitable with oligomeric polyacrylates Polyoxyalkylene and fluoroalkane residues 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) turns.

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 halogen-substituted phosphates mentioned, also inorganic flame retardants, such as. B. alumina hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate, expanded graphite and calcium sul fat, or cyanuric acid derivatives, such as. B. melamine, or mixtures of at least two flame retardants, such as. B. ammonium polyphosphates and melamine and / or expandable graphite, and optionally starch for Flame retardant made from isocyanate prepolymer blends PU foams are used. Generally it has turned out to be Proven to be 5 to 50 parts by weight, preferably 10 to 40 parts by weight Parts of the flame retardants or mixtures mentioned for every 100 To use parts by weight of components (a) to (c).  

As fillers, in particular reinforcing fillers, are the known, conventional organic and inorganic fillers and Understand reinforcing agents. The following are examples: inorganic fillers such as B. silicate minerals, for example Layered silicates, such as antigorite, serpentine, hornblende, amphibole, chryso til, zeolites, talc; Metal oxides such as B. kaolin, aluminum oxides, Aluminum silicate, titanium oxides and iron oxides, metal salts such as. B. chalk, Heavy spar and inorganic pigments such as cadmium sulfide, zinc sulfide, as well as glass particles. Organic fillers come in, for example Consideration: 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 0.5 to 50% by weight, preferably 1 to 10 wt .-%, based on the weight of components (a) to (c) in love.

Details of the other usual tools mentioned above (f) are the specialist literature, for example the monograph by J. H. Saunders and K.C. Fresh "High Polymers" Volume XVI, Polyurethanes, Part 1 and 2, publisher Interscience Publishers 1962 and 1964, or the Plastic manual, polyurethane, Volume VII, Carl Hanser Verlag, Munich, Vienna, 1st and 2nd edition, 1966 and 1983.

Further preferred features and embodiments of the invention result from the following examples.

example 1 Production of the lignin-containing isocyanate prepolymer according to the invention mixture

Lignin-containing prepolymers according to the invention were used produced three different unmodified lignins: Kraftlignin AT and two organosolvlignins. First, the lignin powders were made in Polyoxypro pylene glycol with molecular weight 2000 stirred in and with separation of water for 5 hours at 150 ° C and under reduced Treated pressure of 2 mbar. Then the obtained was drained serte lignin suspension slowly with stirring in the presented, to 80 ° C. heated isocyanate metered in and to complete the reaction Stirred at 80 ° C or 120 ° C for 2 hours.

This gave lignin-containing isocyanate prepolymer mixtures, the viscos strongly depends on the type of lignin but also on the structure of the used Polyisocyanate was dependent. The viscosity was below 1000 mPa · s at 25 ° C, measured with a rotary viscometer, and with lignin kept in the prepolymer of <20 wt .-%. For storage stability speaks the check of viscosity and -N = C = O content after 60 Days (Table 1, Experiment 1) and the fact that the prepolymer bil at higher temperatures not to higher viscosities or significantly changed -N = C = O contents (Table 1, Experiment 1 to 3).  

Table 1

-N = C = O prepolymers from lignin

Suspensions in polyoxypropylene glycols

Table 1 shows that the isocyanate prepolymer according to the invention Mixtures are very stable physically and chemically. This is a particular advantage of the invention.

Example 2 Manufacture of polyurethane parts

Using the lignin-containing isocyanate prepo according to the invention Lymer mixtures according to Example 1 were flexible polyurethane foams manufactured.

A polyoxypropylene started with glycerin was used as the basic polyetherol. Polyoxyethylene block polyol containing primary hydroxyl end groups greater than 80%, a hydroxyl number of 35 mg KOH / g polyol and a viscosity of 850 mPa · s at 25 ° C, measured according to DIN 51562 with an Ubbelohde viscometer.

A polyoxypropylene started with glycerin was used as the cell opener polyol. polyoxyethylene polyol with an ethylene oxide content of 70 wt .-%, bezo gene on the alkylene oxide content, a hydroxyl number of 42 mg KOH / g Polyol and a viscosity of 980 mPa · s at 25 ° C, measured after DIN 51562 with an Ubbelohde viscometer.

A polyiso containing urethane groups was used as the reference substance cyanate mixture with an -N = C = O content of 24.5% by weight from diphenylmethane diisocyanates (40.7% by weight), polyphenyl polymethylene  polyisocyanates (30.4 wt .-%), polyoxypropylene glycol with a through average molecular weight of 2000 (10 wt .-%) and the pre called cell opener polyol (10 wt .-%) used.

For the production of the flexible PU foams, the polyol and Isocyanate components with an NCO index = 80 (80 -N = C = O groups to 100 OH groups) mixed intensively and the reaction mixture in an open beaker (determining the reaction times and the free foam density) and in a heatable mold (mold temperature 50 ° C) with the dimensions 400 × 400 × 100 mm (determination of the mechanical properties of the foams) and there foaming left.

Recipe for the production of flexible polyurethane foams by weight share

Component (A): mixture consisting of:

Component (B): isocyanate mixture according to Table 2

In the experiments described in Table 2, the ver Polyisocyanatmi containing the same substance used urethane groups fully or proportionately as specified against the invention lignin-containing isocyanate-prepolymer mixture exchanged.  

Table 2

Foam tests were carried out:
Density determination DIN 53420
Elasticity measurement: rebound elasticity measured according to a BASF internal measurement method
Compression set DIN 53572
Compression hardness DIN 53577
Tear resistance DIN 53515
Tensile strength DIN 53571.

The numbers in Table 2 show that the Isocya according to the invention nat prepolymer mixtures for the production of polyurethane foam bodies that have improved properties. especially the increased elongation at break, the increased tensile strength and the increased further tensile strength is remarkable and a surprising result represents.

Claims (13)

1. isocyanate prepolymer mixture containing urethane groups and reactive isocyanate groups bound, characterized in that they have an NCO content of 2.5 to 30 wt .-%, based on the total weight of the isocyanate prepolymer mixture, and are available by implementing

• b1) 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate, an isomer mixture of 4,4'- and 2,4'- or 4,4'-, 2,4'- and 2,2'-diphenyl methane diisocyanates or a mixture of diphenyl methane diisocyanates and polyphenyl polymethylene polyisocyanates
• b2) a suspension that contains
  • b2i) at least one polyoxyalkylene glycol with a molecular weight from 400 to 6000, preferably from 1000 to 3000, selected from the group of polyoxypropylene glycols, polyoxypropylene-polyoxyethylene glycols and mixtures thereof and
  • b2ii) lignin.

2. Isocyanate-prepolymer mixture according to claim 1, characterized in that the suspension, based on the total weight of b2i) and b2ii) of the suspension, contains or preferably consists of Chen wesentli

• b2i) 99 to 30% by weight, preferably 50 to 40% by weight, at least one polyoxyalkylene glycol with a molecular weight of 400 to 6000, in particular 1000 to 3000, selected from the group of polyoxypropylene glycols, poly oxypropylene-polyoxyethylene glycols and mixtures thereof, and
• b2ii) 1 to 70% by weight, preferably 50 to 60% by weight, of lignin.

3. Isocyanate prepolymer mixture according to one of the preceding Claims, characterized by a -N = C = O content of 5 to 25% by weight, based on the total weight of the isocyanate prepoly mer mix. 4. Isocyanate prepolymer mixture according to one of the preceding Claims, characterized in that as polyoxyalkylene glycol Polyoxypropylene-polyoxyethylene glycols are used, which one Content of oxypropylene groups based on at least 60 wt .-% have on the polyoxyalkylene groups. 5. Isocyanate prepolymer mixture according to one of the preceding Claims, characterized in that a lignin is used, no special chemical treatment for this further has undergone processing. 6. Use of the isocyanate prepolymer mixture according to one of the Claims directed at isocyanate prepolymer mixtures Manufacture of polyurethane. 7. A process for producing an isocyanate prepolymer mixture which Urethane groups and reactive isocyanate groups bound  contains, by implementing the in the on isocyanate prepolymer Mi organic polyiso cyanates (b1) and suspensions (b2). 8. The method according to claim 7, characterized in that the Suspension (b2) before the reaction with the polyisocyanates a temperature of 60 to 130 ° C, preferably under a pressure of a maximum of 30 mbar over a period of 1 to 8 hours, particularly preferably in the presence of esterification catalysts, treated. 9. Process for the production of compact or cellular polyurethanes, preferably PU foams, by reacting

• a) higher molecular weight compounds with at least two reactive hydrogen atoms, preferably polyhydroxyl compounds, with
• b) liquid polyisocyanate compositions containing urethane groups in the presence or absence of
• c) chain extenders and / or crosslinking agents,
• d) blowing agents,
• e) catalysts and
• f) aids,

characterized in that Polyisocyanate compositions (b) are used, at least partly from an isocyanate prepolymer mixture according to one of the claims directed to isocyanate prepolymer mixtures. 10. The method according to claim 9, characterized in that the higher molecular compounds (a) have a functionality of 2 to 8 and have a hydroxyl number of 25 to 500 and preferably from  Polyhydroxyl compounds exist, which are particularly selected from the group of polythioether polyols, polyesteramides, hydrox yl group-containing polyacetals, hydroxyl group-containing aliphatic Polycarbonates, polyester-polyols, polymer-modified polyether polyols, preferably polyether polyols and mixtures of mind at least two of the polyhydroxyl compounds mentioned. 11. The method according to any one of claims 9 or 10, characterized records that as blowing agent (d) water, linear and cyclic Alkanes with 3 to 7 carbon atoms or mixtures thereof are used. 12. Method according to one of the production of polyurethane directed claims, characterized in that the high molecular weight laren compounds (a) and the polyisocyanate compositions (b) in the presence of a blowing agent (d) and with the formation of a Polyurethane foam body can be implemented in a mold.