DE102007015802A1 - Shaped body of cellulose-containing materials - Google Patents

Abstract

Shaped body of cellulose-containing material and crosslinked 2-component polyurethane binders, consisting of 99 to 85 wt .-% cellulose-containing material together with 1 to 15 wt .-% of a 2-K PU binder, wherein the 2-component PU binder contains - 25 to 90 wt .-% of oleochemical polyols having a functionality between 2.5 to 5 - 1 to 50 wt .-% of 2 to 4-functional polyether polyols having a molecular weight between 250 to 20,000 g / mol, - 0.1 to 5 wt .-% aliphatic or aromatic di- or triamines having primary and / or secondary amino groups, - 1 to 30 wt .-% of a mixture of water and a C <SUB> 2 </ SUB> - to C <SUB> 100 </ SUB> carboxylic acid, - 1 to 25% of drying and / or semi-drying oils, and - optionally further additives, wherein the ingredients supplement to 100%, and at least one aromatic polyisocyanate having an NCO / OH ratio of 1 : 1 to 3.5: 1.

Description

The The invention relates to shaped bodies made of cellulose-containing materials and 2K polyurethane compositions having a low density. Furthermore, 2K PU binders are used to produce such shaped bodies described.

moldings from wood materials are known. This will be wood powder, fibers or shavings with different binders with each other bonded. These shaped bodies can be plates or Be blocks or have other forms. Such shaped bodies are known for example as chipboard or MDF boards. It is it is customary, the cellulosic materials to be joined with phenolic, urea or melamine resin binders together to stick together. It is also known such moldings also to bond with polyurethane systems.

It It is expedient that such moldings a stable Have surface. Furthermore, the mechanical Properties of such shaped bodies, such as transverse tensile and flexural strength, Dimensional stability or freedom from migrates or vapors, be guaranteed. There is a general interest in that such moldings have a low density. In order to should be made of such moldings used body, for example Furniture parts to be light and manageable. A deterioration However, a mechanical property should not be given.

The is known DE 195 26 032 A in which polymer wood moldings are described which consist of wood particles or cellulose particles and 2-component polyurethane binders. These moldings contain more than 10 parts by weight of PU binder per 100 parts of wood components. The preparation is carried out under the autogenous pressure of the reaction mixture. This consists of polyether polyols, low molecular weight polyols such as glycerol, as well as catalysts and MDI as crosslinking component. The pressure required in the production process is generated by CO ₂ formation with the moisture of the wood particles and with the added water.

Furthermore, there are the EP 1037733 , in which likewise shaped bodies of wood particles and PU binder are described. The PU compositions described therein consist of low molecular weight polyethers, low molecular weight polyols, such as glycerol or dipropylene glycol, and of carboxylic acids. These carboxylic acids should react with isocyanates and thereby form CO ₂ , which lead to foaming of the binder. Furthermore, water from residual moisture of the wood particles is used in the reaction, this being between 5 and 20% by weight of the wood particles.

Furthermore, the EP 1131386 known. In this application stone composite panels are described. These consist of a mineral shaped body, are molded on the polyurethane foams. In this polyurethane foams up to 80% fillers, such as stone dust, sand, chalk, wood chips, wood flour or foam glass can be added. Due to the high density heavy moldings are obtained with a high density. These are not comparable with conventional polymer wood moldings. As binders, isocyanates are described with polyols, as foaming agents fatty acids or small amounts of water.

Furthermore, the WO 02/45960 known. In this application also composite body of mineral moldings and polyurethane foams are described. In the corresponding manufacturing process, heavy moldings are obtained. These are produced by foaming the PU binder with introduced carboxylic acids or water and filling the appropriate shape by the autogenous pressure. It is described that up to 80% of stone powder, chalk or wood flour can be added to this PU binder if necessary. An application of such compositions to low-density wood articles is not described.

outgoing From the known prior art, the task arises that Shaped body based on cellulose-containing materials produced together with 2K polyurethane compositions, which have a low density. Regardless of the low Density, these moldings are an improved swelling behavior to show moisture and adequate mechanical stability have and have a stable surface.

The Invention is solved by a molding after Claim 1. Another object of the invention are the appropriate Polyurethane compositions which give such shaped bodies.

As cellulosic material are in the moldings vegetable fibers, such as tree wool, jute, flax, hemp, bast, sisal, ramie, cosco fibers, yucca fibers or manila, paper and pulp yarns. As woodponds can span or powdered wood particles are used. These can be made of hard or softwood. Furthermore, flax and hemp shives, straw particles, bamboo shavings, nut shells, cork schnitzel or bagasse may be included. It may also be crushed wood-containing waste from the chipboard or furniture industry.

In lie the moldings of the invention the particles in the form of wood shavings, wood flour or others cellulose-containing materials in particle sizes of not more than 5 mm thick, 50 mm wide and 100 mm long, in particular as chips or fibers of different sizes.

The Moisture of the cellulose-containing materials for the preparation of the invention Shaped body can be up to 20 wt .-% amount. This may optionally increased by moistening or by drying at elevated Temperature be lowered. By the reaction with the isocyanates the water content of the finished shaped body is reduced.

The Moldings according to the invention can additionally z. As wires, cables, wire nets, rods or the like as inserts or reinforcing agents contain.

The Contain molded body according to the invention for binding the cellulosic components a foamed, crosslinked polyurethane composition. This composition arises by crosslinking a 2K PU composition. A necessary component is a polyisocyanate component. Polyisocyanates suitable for these components are suitable are the known polyfunctional Isocyanates with an average of 2 to 6, preferably to 4 and in particular 2 or 3 isocyanate groups per molecule. The usable polyisocyanates may be aromatic, cycloaliphatic or aliphatic Be isocyanates.

Examples of suitable aromatic polyisocyanates are the isomers of toluene diisocyanate (TDI) isomerically pure or as a mixture, naphthalene-1,5-diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), diphenylmethane-2,4'-diisocyanate, mixtures, xylylene diisocyanate (XDI), 4,4'-diphenyl-dimethylmethane diisocyanate, di- and tetra-alkyl-diphenylmethane diisocyanates, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate. Examples of suitable cycloaliphatic polyisocyanates are the hydrogenation products of the aforementioned aromatic diisocyanates such. 4,4'-dicyclohexylmethane diisocyanate (H ₁₂ MDI), 1-isocyanatomethyl-3-isocyanato-1,5,5-trimethylcyclohexane (isophorone diisocyanate, IPDI), cyclohexane-1,4-diisocyanate, hydrogenated xylylene diisocyanate (H ₆ XDI), 1-methyl-2,4-diisocyanato-cyclohexane, tetramethylxylene diisocyanate (m-TMXDI, p-TMXDI) and dimer fatty acid diisocyanate. Examples of aliphatic polyisocyanates are tetramethoxybutane-1,4-diisocyanate, butane-1,4-diisocyanate, hexane-1,6-diisocyanate (HDI), 1,6-diisocyanato-2,2,4-trimethylhexane, 1,6- Diisocyanato-2,4,4-trimethylhexane, butane-1,4-diisocyanate and 1,12-dodecane diisocyanate (C ₁₂ DI). In addition to the abovementioned aliphatic and cycloaliphatic isocyanates, their isocyanurates or biurets, in particular those of HDI or IPDI, are also to be used.

in the In general, aromatic isocyanates are preferred, preferably diphenylmethane diisocyanate, either in the form of pure isomers, as isomer mixtures and the so-called crude MDI. Furthermore you can low molecular weight NCO-containing reaction products of MDI or the TDI with low molecular weight diols, such as. For example, ethylene glycol, diethylene glycol, Propylene glycol, dipropylene glycol or triethylene glycol used become.

One further constituent of the 2-component PU composition according to the invention is a polyol component, which is a mixture of various Polyols and other additives and additives.

It is essential to the invention that the PU binder oleochemical Contains polyols. Among oleochemical polyols to polyols understood based on natural oils and fats be, for. As the reaction products of epoxidized fatty substances with mono-, di- or polyfunctional alcohols or glycerol esters long-chain fatty acids that are at least partially hydroxylated are substituted.

An example of such compounds are the ring-opening products of epoxidized triglycerides, ie epoxidized fatty acid glycerol esters in which the ring opening has been carried out to obtain the ester bonds. For the preparation of the ring-opening products one can assume a variety of epoxidized triglycerides of plant or animal origin. Thus, for example, epoxidized triglycerides are suitable which have 2 to 10 percent by weight of epoxide oxygen. Such products can be prepared by epoxidation of the double bonds of a series of fats and oils, eg. B. beef tallow, palm oil, peanut oil, rapeseed oil, cotton seed oil, soybean oil and sunflower oil. Particularly preferred epoxidized triglycerides are epoxidized soybean oil and epoxidized linseed oil.

When Alcohols for the ring opening of the epoxidized Triglycerides can be methanol, ethanol, propanol, isopropanol, Butanol, hexanol, 2-ethylhexanol, fatty alcohols having 6 to 22 C atoms, Cyclohexanol, benzyl alcohol, 1,2-ethanol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol. 1,6-hexanediol, neopentyl glycol, trimethylolpropane, glycerol, Trimethylolethane, pentaerythritol, sorbitol and ethergruppenhaltige Hydroxy compounds such as alkyl glycols or oligomeric glycols and oligomeric glycerols are used.

The ring-opening reaction of epoxidized fatty acid esters or triglycerides with an alcohol may optionally be followed by transesterification with itself or other post-added triglycerides. Such oleochemical polyols are, for. B. in the German patent application DE-A 41 28 649 described.

A Another group of oleochemical polyols are ring-opening and transesterification products of epoxidized fatty acid esters lower alcohols, ie of epoxidized fatty acid methyl, ethyl, propyl or butyl esters. Preference is given here to the ring-opening or transesterification products with alcohols of functionality 2 to 4, in particular the reaction products with ethylene glycol, Propylene glycol, oligomeric ethylene glycols, oligomeric propylene glycols, Glycerol, trimethylolpropane or pentaerythritol. The production Such products can be prepared by known epoxidation or ring opening methods carried out, wherein the transesterification during or after the ring opening step by removing the lower alcohol from the reaction equilibrium can be carried out.

The oleochemical polyols also include the reaction products of epoxidized fatty alcohols with C ₂ -C ₈ -alcohols of functionality 1 to 10, in particular 2 to 4.

In the context of the invention, the use of oleochemical polyols is possible, which via transesterification of di- or polyfunctional alcohols with triglycerides, such as. As palm oil, peanut oil, rapeseed oil or sunflower oil, are accessible. Likewise, polyols can be used, according to the doctrine of DE-A 41 24 665 obtainable by the transesterification of polymerized glycerol with the abovementioned triglycerides. Resin-modified oleochemical polyols can also be used.

The According to the invention suitable oleochemical polyols Hydroxyl numbers from 50 to 400, preferably 100 to 250 mg KOH / g solids. These polyols have generally a mean functionality between 2.5 until 5.

Especially preferred is the use of castor oil or dimerdiols as oleochemical polyols and those polyester polyols, which by complete ring opening of epoxidized triglycerides an at least partially olefinically unsaturated fatty acid-containing Fat mixture with one or more alcohols having 1 to 12 carbon atoms and subsequent partial transesterification of the triglyceride derivatives to alkyl ester polyols having 1 to 12 carbon atoms in the alkyl radical become.

In the PU composition according to the invention can additionally contain other polyols, in particular the known polyhydroxy polyethers of the molecular weight range from 250 to 20,000 g / mol, in particular below 15,000 g / mol, preferably 400 to 10,000 g / mol, with 2 to 10 OH groups per molecule, in particular with 2 to 4 OH groups. Such polyhydroxypolyethers be in a conventional manner by alkoxylation of suitable Get starter molecules, z. As of water, propylene glycol, glycerol, Trimethylolpropane, sorbitol or cane sugar. Suitable alkoxylating agents are in particular propylene oxide and possibly also ethylene oxide. Preferably The liquid polyether compounds are suitable with two or three hydroxyl groups per molecule, such as. B. di- and / or trifunctional polypropylene glycols in the molecular weight range from 250 to 10,000 g / mol, preferably in the range of 400 to 6,000 g / mol. It may be random and / or block copolymers of the ethylene oxide and propylene oxide are used.

A Another group of preferably usable polyethers are the Polytetramethylene glycols, the z. B. by the acidic polymerization be prepared from tetrahydrofuran, this is the molecular weight range the polytetramethylene glycols between 250 and 6000 g / mol, preferably in the range of 400 to 4000 g / mol.

The inventively suitable polyol mixture should contain 25 to 90 wt .-% of oleochemical polyols, in particular 35 to 70 wt .-%. Furthermore, the amount of polyether polyols should be between 1 and 50 Wt .-%, in particular between 5 to 35 wt .-%, each based on the polyol component. A particular embodiment works with a mixture of polyether polyols, in particular a difunctional and a trifunctional polyether polyol.

Possibly. is it possible that in some cases even up to 20% by weight preferably up to 15 wt .-% of low molecular weight polyhydroxyl compounds are included. The molecular weight should be between 60 to 250 g / mol. These can be polyols with 2 to 6 OH groups such as glycol, butanediol, hexanediol, octanediol, Glycerol, pentaerythritol, trimethyloipropane or sugar alcohols. These ingredients increase the urethane group concentration of the polymer and affect the hardness of the crosslinked Adhesive.

In the composition of the invention must continue to contain carboxylic acids. These react with the isocyanates in the presence of catalysts with elimination of carbon dioxide. Among carboxylic acids are acids understood that one or more, preferably a carboxyl groups and preferably contain 6 to 100 carbon atoms. The carboxyl groups are with saturated or unsaturated alkyl radicals connected, which has a linear, branched or cyclic structure own or with aromatic residues. These can be more Heteroatoms such as ether, ester, halogen and hydroxy groups. In addition, carboxyl-terminated polyesters and Polyether and dimer and trimer fatty acids can be used. Likewise, partial esters of acids are more suitable as a carboxyl group. Further inventive Compounds are esters and partial esters of di- and triols, tetrols, Containing pentoles, sugars and carbohydrates with carboxylic acids more than one carboxyl group. Also have ring opening products from epoxides and these polycarboxylic proved to be suitable.

The mentioned compounds can be used in mixtures be, with liquid products or liquid Mixtures are preferred, as well as compounds that easily with the remaining ingredients to liquid mixtures process.

Around the segregation of the constituents of the polyol component To avoid, it is appropriate that the inventive Composition in the polyol component still solubilizing May contain amino compounds. These compounds cause a Solving mediation between the components without Foaming is adversely affected. As amines are suitable aliphatic or aromatic di- or triamines with primary and / or secondary amino groups, especially heterocyclic Amines. The amines must be at least 3, but preferably Contain 6 carbon atoms. The amines can also be one Possess hydroxy function. The amount should be between 0.1 to 5 wt .-% be.

When Amines are suitable for. Ethylenediamine, 1,2- and 1,3-propylenediamine, Hexamethylenediamine, 1,4- and 1,6-toluenediamine, 4,4'-diphenylmethanediamine and diethylenetriamine. It can also be hydroxy functional Polyamines such. B. N- (2-aminoethyl) ethanolamine can be used. In particular, piperazine and aminoalkyl- or hydroxyalkyl-substituted are also suitable Piperazines, especially aminoethylpiperazine. The mixing ratio the aforementioned amines to the carboxylic acids should thereby 1: 0.3 to 1: 100.

According to the invention, it is necessary that the reaction mixture still contains water. The water reacts under CO ₂ formation with the isocyanate groups. The water can be added separately or it is included in the polyol component. The amount of water is important to achieve a sufficient hardness and strength of the molding. The water content of the polyol component can be between 0 and 10 wt .-%, preferably it is between 0.3 and 5 wt .-%.

The equivalent ratio between carboxylic acid and water should be between 1: 0.5 and 200. In particular, the ratio should be 1: 0.9 to 1:20. Both components cause CO ₂ cleavage from the isocyanates. If the amount of water chosen too high, the swelling behavior of the finished, crosslinked moldings is poor, ie the stability to moisture of cellulose-based moldings is reduced. If the content of carboxylic acids is too high, the stability to moisture is also reduced. Overall, the content of the mixture of carboxylic acid and water should be between 1 and 30% by weight, preferably between 2 and 20% by weight, based on the polyol component

It is essential that the compositions according to the invention contain from 1 to 25% by weight of drying and / or semi-drying oils, in particular from 2.5 to 20% by weight. Drying or semi-drying oils are, for example, esters of glycerol with unsaturated fatty acids, for example more than 20% linoleic acid or linolenic acid. Examples of such drying or semi-drying oils are cottonseed oil, thistle oil, wood oil, hemp oil, linseed oil, poppy oil, oiticica oil, perilla oil, rapeseed oil, soybean oil, safflower oil, Son orange flower oil or walnut oil. Furthermore, liquid tall oils or turpentine oils are suitable. These are generally natural products, but they can be modified by chemical reactions. The iodine value of the drying or semi-drying oils should be between 100 to 250. Preference is given to using drying oils, such as linseed oil, wood oil, oiticica oil, poppy seed oil or perilla oil, if appropriate also as mixtures.

By The added oils generally increase the flexibility of the cross-linked adhesive. Another Advantage of the drying oils is in an influence the water absorption of the adhesive or the bonded substrate determine. Furthermore, the viscosity by addition of low-viscosity drying and / or semi-drying oils to be influenced. If such oils are included, it is appropriate optionally add drying catalysts, in particular the known Metal-containing catalysts. It can be metal catalysts, so-called siccatives, such as Mn, Zr, Fe or co-octoate. Such products are known to the person skilled in the art.

The Compositions according to the invention usually react at room temperature. For an accelerated However, a reaction can also take place. It However, it is preferred that the mixture contains catalysts. This can be, for example, organometallic compounds or tert. Be amines. Examples of organometallic compounds are tin (II) salts of carboxylic acids, strong bases such as alkali hydroxides, -Alcoholates and phenolates, e.g. Di-n-octyl-tin-mercaptide, dibutyltin, dilaurate, stannous diethylhexoate; Tin oxides and sulphides and thiolates, such as bis (tributyltin) oxide, dioctyltin dodecylthiolate, tributyltin (thioglycolic acid 2-ethylhexoate), or dibutyl and dioctyltin bis (thioethylene glycol 2-ethylhexoate).

additionally suitable as a catalyst are also aliphatic tertiary Amines, in particular with cyclic structure. Among the tertiary Amines are also suitable, which additionally still opposite the isocyanate-reactive groups, in particular hydroxyl and / or amino groups. Examples are dimethyl or Diethyl-monoethanolamine, triethanolamine, tripropanolamine, trihexanolamine, Tricyclohexanolamine, diaza-bicyclo-octane, triethylamine, dimethylbenzylamine, Bis-dimethylaminoethyl ether, tetramethylguanidine, bis-dimethylaminomethyl-phenol, 2,2'-dimorpholinodiethyl ether, 2- (2-dimethylaminoethoxy) ethanol, 2-dimethylaminoethyl-3-dimethylaminopropyl ether, bis (2-dimethylaminoethyl) ether, or N, N, N, N-tetramethylbutane-1,3-diamine. The catalysts can also in oligomerized or polymerized form, for. B. as N-methylated polyethyleneimine.

If the CO ₂ elimination from the isocyanate-carboxylic acid reaction is to take place intensified, it is expedient to use amino-substituted pyridines and / or N-substituted imidazoles as additional catalysts. Particularly suitable are 1-methylimidiazole, 2-methyl-1-vinylimidazole, 1-allylimidazole, 1-phenylimidazole, 1,2,4,5-tetramethylimidazole, 1 (3-aminopropyl) imidazole, N-dodecyl-2-methyl-imidazole , Pyrimidazole, 4-dimethylamino-pyridine, 4-pyrrolidinopyridine, 4-morpholino-pyridine and 4-methylpyridine. The amount of catalysts should be from 0.1 to 2 wt .-%.

Out the polyols and optionally the additives and auxiliaries is by known method prepared the polyol component. From the polyol component and the isocyanate component becomes the invention 2K PU composition made by mixing. This should be immediate mixed after preparation with the cellulosic solids become. Another procedure works so that the solid particles be mixed with the polyol component. After that, this mixture becomes the isocyanate component is added and mixed. By the share on drying oils is the viscosity of the composition reduced so that a good miscibility is ensured. method and machines for the production of moldings are those skilled in the art known. The amount of polyisocyanates is chosen that an NCO: OH ratio of 1: 1 to 3.5: 1 is obtained. In general, it is preferable if there is an excess Isocyanate groups is present, d. H. the relationship should over 1.2: 1 amount.

The amount of cellulosic materials should be between 99 to 85 wt .-%, the amount of 2-component polyurethane composition 1 to 15 wt .-%. The shaped bodies according to the invention are produced in a manner known per se. The cellulose-containing materials, in particular wood chips or fibers, are homogeneously mixed with a mixture of the 2-component PU binder. The resulting mixture is processed in single or twin belt presses into plates or in special shapes to form bodies. Under pressure and at elevated temperature, for example at 80 to 230 ° C, the mixtures are crosslinked and transferred to the cured molding. These shaped bodies have a density of less than 1 g / cm ² , for example between 0.25 to 0.70 g / cm ³ .

The shaped bodies according to the invention are mechanically stable. They can be good in different forms be prepared or cut into various shapes. They have a low density, but can be provided with fasteners such as screws, etc., without any breakage of the moldings is observed. Despite the low density, they have a high screw pullout strength.

Especially show these moldings only a low swellability Water, that is, the increase in thickness is less than 1%. Known hydrophobization process by coating the Wood chips with paraffin are not necessary. This can a simplification of the manufacturing process can be achieved.

One Advantage of the 2-component polyurethane binder according to the invention is that the OH components are easy to manufacture. The known incompatibilities of polyols, organic Carboxylic acids and water are avoided. These OH components are storage stable. Due to the homogeneous composition are homogeneous Shaped body produces a uniform Have distribution of binder and cellulosic materials.

By the selected mixing ratio of carboxylic acid and water to polyol will ensure that ratio of crosslinking of the 2-component PU binder for foaming so adjusted is that connecting and homogeneously connecting the individual cellulose particles is possible. An additional hydrophobing the cellulosic particle is not necessary.

The invention will be explained in more detail by embodiments. Example 1 (comparison): a) polyol component mass fractions dipropylene 18.7 glycerin 4.5 Polypropylene glycol, Mn 400 g / mol 41.0 Polypropylene triol, Mn 250 g / mol 31.8 water 2.5 Tegostab 8404 (Goldschmidt) 1.1 DABCO 0.4 b) isocyanate component: MDI (crude product) 205 Example 2 (comparison): a) polyol component mass fractions dipropylene 4.0 glycerin 5.0 castor oil 52.5 Polypropylene glycol, Mn 400 14.0 PPG triol, Mn 250 15.6 castor oil 4.0 water 2.2 rapeseed fatty acid 3.5 DABCO 0.5 Tegostab B 8404 1.2 aminoethylpiperazine 1.5 b) isocyanate component Crude MDI 145.0 Example 3 (comparison): a) polyol component mass fractions dipropylene 4.0 glycerin 5.0 castor oil 51.0 Polypropylene glycol, Mn 400 10.0 PPG Triol, Mn 250 12.2 rapeseed fatty acid 12.5 water 2.2 Tegostab B 8404 1.2 DABCO 0.4 aminoethylpiperazine 1.5 b) isocyanate component Crude MDI 140 Example 4, according to the invention: a) polyol component mass fractions dipropylene 4.0 glycerin 6.0 castor oil 48.1 Polypropylene glycol, Mn 400 g / mol 8.0 PPG triol, Mn 250 g / mol 11.7 rapeseed fatty acid 12.0 water 2.2 Tegostab B 8404 1.2 DABCO 0.4 N-methylimidazole 0.4 aminoethylpiperazine 1.5 linseed oil 5.5 b) isocyanate component Crude MDI 140 Panel construction: 16 mm three-layer board, 25% top layer, 75% middle layer Wood: jaw Adhesive share: 8% in top layer, 6% in middle layer (based on dry wood) waterproofing: 1% hydrophobing wax Sasol 730 (paraffin wax)

Production of the plates:

First are to be mixed polyol component and optionally the hydrophobing wax.

The chips are then mixed with the polyol and then with the isocyanate component in a free-fall cascade drum. Thereafter, the mixture is transferred to a mold and pressed at 180 ° C press temperature for 3 minutes. example Example 2 Example 3 Example 4 Density: 475 480 465 480 480 475 470 480 Kg / m ³ Hydrophobing in%: 0 1 0 1 0 1 1 0 Swelling after 2 h in%: 10.5 6.7 6.1 2.0% 5.0 1.5 0.9 0.9

The Transverse tensile strengths of the plates produced are 0.3 MPa. The mean values of flexural strength and modulus of elasticity at 6.2 MPa and 1250 MPa.

The comparative experiments show that a mixture of short-chain di- and trifunctional polyols with a chain extender or a polyol mixture with castor oil or a high proportion of the foaming agent cause a still to be improved water swelling. The swelling can be reduced by adding a hydrophobing wax.

in the Inventive Example 4 leads the Addition of the drying oil to a reduction of swelling. It is no longer necessary to add hydrophobing wax.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19526032 A [0004]
• - EP 1037733 [0005]
• - EP 1131386 [0006]
• WO 02/45960 [0007]
• - DE 4128649 A [0021]
• - DE 4124665 A [0024]

Claims (14)

Shaped body of cellulose-containing material and crosslinked 2-component polyurethane binders, consisting of 99 to 85 wt .-% cellulosic material together with 1 to 15 wt .-% of a 2-K PU binder, wherein the 2-component PU binder contains - 25 to 90 wt .-% of oleochemical polyols having a functionality between 2.5 to 5 - 1 to 50 wt .-% of 2 to 4-functional polyether polyols having a molecular weight between 250 to 20,000 g / mol, - 0.1 to 5 wt .-% aliphatic or aromatic di- or triamines having primary and / or secondary amino groups, - 1 to 30 wt .-% of a mixture of water and a C ₂ to C ₁₀₀ carboxylic acid, - 1 to 25% drying and or semidrying oils, and - optionally further additives, wherein the ingredients supplement to 100%, and at least one aromatic polyisocyanate having an NCO / OH ratio of 1: 1 to 3.5: 1. Shaped body according to claim 1, characterized in that it has a density between 250 and 700 kg / m ³ , in particular 350 to 600 kg / m ³ . Shaped body according to claim 1 or 2, characterized characterized in that the drying oil is selected is made of cotton oil, linseed oil, poppy seed oil, Hemp oil, wood oil, oiticica oil, perilla oil, Rapeseed oil, soybean oil, safflower oil, sunflower oil, walnut oil, Tall oil and / or turpentine oil. Shaped body according to claim 1 to 3, characterized characterized in that the 2K PU binder additionally 1 to 20 wt .-% of at least one low molecular weight polyol having a molecular weight are contained below 250 g / mol. Shaped body according to one of the claims 1 to 4, characterized in that the 2K PU binder in addition 0.1 to 2% of catalysts from the group of amino-substituted Pyridines, N-substituted imidazoles, organometallic compounds, aliphatic tertiary amines and alkali alcoholates are. Shaped body according to one of the claims 1 to 5, characterized in that as oleochemical polyol Castor oil is used. Shaped body according to one of the claims 1 to 6, characterized in that the equivalent ratio between Carboxylic acid and water 1: 0.5 to 1: 200. Shaped body according to claim 7, characterized that the equivalent ratio of amine: carboxylic acid 1: 0.3 to 1:20. is. Shaped body according to one of the claims 1 to 8, characterized in that as aliphatic or aromatic Di- or triamine a heterocyclic amine is used. Shaped body according to one of claims 1 to 9, characterized in that the PU binder in the OH component consists of - 35 to 70 wt .-% of oleochemical polyols having a functionality of from 2.5 to 5, - 3 to 35 wt .-% 2- to 4-functional polyether polyols having a molecular weight between 250 to 15000 g / mol, - 0.1 to 5 wt .-% of an aliphatic or aromatic di- or triamine, - 2 to 20 wt .-% of a mixture from water and a C ₂ to C ₁₀₀ monocarboxylic acid, from 2.5 to 20% by weight of drying and / or semi-dry oils, from 0.1 to 2% by weight of catalysts and, if appropriate, additives. 2-component polyurethane binder consisting of a polyol component and an isocyanate component, wherein the polyol component contains - 25 to 90 wt .-% oleochemical polyols having a functionality between 2.5 to 5, 1 to 50 wt .-% 2 to 4 functional polyether polyols with a molecular weight between 250 to 15,000 g / mol, - 0.1 to 5 wt .-% aliphatic or aromatic di- or triamines, From 1 to 30% by weight of a mixture of water and a C ₂ to C ₁₀₀ monocarboxylic acid, from 1 to 25% by weight of drying and / or semidrying oils, from 0.1 to 2% by weight of catalysts and, if appropriate, Additives. 2-component PU binder according to claim 11, characterized in that that as a drying oil linseed oil or wood oil is included. 2-component PU binder according to claim 11 or 12, characterized in that at least one metal salt of an organic C ₁ to C ₁₂ carboxylic acid is present as catalyst. Use of 2-component PU binders according to one of Claims 11 to 13 for the production of moldings from cellulosic materials with low density.