AT501049B1 - METHOD FOR ACYLATING AN IN PARTICULAR CELLULOSE AND / OR HEMICELLULOSE AND / OR LIGNIN EFFECTIVE MATERIAL AND MATERIAL THEREFORE AVAILABLE - Google Patents

Description

2 AT 501 049 B1

The invention relates to a process for the acylation of a particular cellulose and / or He-micellulose and / or lignin-containing material.

Furthermore, the invention relates to an acylated material.

Finally, the subject of the invention is a composite material which contains a cellulose and / or hemicelulose and / or lignin-containing material and a thermoplastic.

Cellulosic, hemicellulose and / or lignin-containing materials, for example wood, are important renewable raw materials and can not only be used as such but also serve as important raw materials for the production of composites, for example wood-polymer composites or particleboard materials. Such composites are cost effective alternatives to plastics and can replace them in many applications.

In comparison with pure plastics, however, composites based on cellulose and / or hemicellulose and / or lignin-containing materials and polymers as base components are generally less dimensionally stable, especially at high humidity, and less weather- and fungus-resistant and less hydrophobic, due to the proportions attributable to cellulose, hemicellulose and / or lignin in the composite material.

In order to improve the properties of cellulose, hemicellulose and / or lignin-containing materials in this regard, numerous processes have already been proposed for the acetylation or acylation of cellulose, hemicellulose and / or lignin-containing materials. In such processes, free hydroxyl groups of a material are esterified, whereby a desired modification of the properties of the material is to be achieved.

In an acetylation is esterified only with acetate-containing reactants, while in an acylation any groups can serve to esterify. In the context of the present invention, the broad term acylation includes the specific term acetylation.

It is known in the art to react cellulosic materials such as wood with acetic anhydride at temperatures of at least about 120 ° C to obtain acetylated materials (e.g., US 5,525,721 A or US 5,431,868 A).

According to WO 2004/048417 A1, it has been proposed to react wood with isopropenyl acetate at temperatures of 50 to 125 ° C. and reaction times of 0.2 to 6 hours in the presence of an acid catalyst in order to obtain acetylated wood.

In addition to the methods of acetylation known from the aforementioned documents, methods for the acylation of cellulosic materials with acid anhydrides or acid chlorides have become known.

The above-mentioned especially with acetic anhydride or acid anhydrides or acid chlorides working methods for the acylation of cellulose and / or hemicellulose and / or lignin-containing materials have the disadvantages that high degrees of acylation only under relatively drastic reaction conditions, such as high temperatures and / or high pressures achieved become.

Another disadvantage of the known methods is that such acylated materials can be insufficiently water-repellent and may absorb water under certain circumstances. If such materials are processed with polymers into composite materials, this disadvantage also occurs in these: Corresponding composite bodies can then be insufficiently dimensionally stable or deform, in particular, at high air humidity without the action of a load.

Based on this, the object of the invention is to provide a generic process with which under mild reaction conditions acylation of free hydroxyl groups can be carried out to a high degree and water-repellent materials are obtainable, which can be processed with a thermoplastic material to form a dimensionally stable composite material. It is a further object of the invention to specify an acylated material which is hydrophobic and can be processed with a thermoplastic to form a dimensionally stable composite material.

Further, it is an object of the invention to provide a composite material which contains a cellulose 15 and / or hemicellulose and / or lignin-containing material and a thermoplastic and which is highly water-repellent and dimensionally stable and has a good fungal resistance.

The procedural object solves a method according to claim 1. Advantageous variants 20 of a method according to the invention are set forth in claims 2 to 20.

The advantages achieved by the invention can be seen in particular in the fact that in an acylation with a mixture of isopropenyl acetate and a carboxylic acid / a carboxylic acid anhydride same degree of acylation under milder reaction conditions, 25 so lower temperature and / or lower pressure and / or in shorter reaction times can be achieved than before. Thus, for example, a reaction according to the invention with a mixture of isopropenyl acetate and acetic acid leads to the same degree of esterification in comparison with a reaction with isopropenyl acetate under milder reaction conditions. It is also advantageous that acylated materials which have a higher hydrophobicity than materials treated with isopropenyl acetate can be obtained owing to a carboxylic acid (s) or one or more carboxylic anhydrides (s) intended for a reaction. As a result, according to the invention acylated materials can be processed with a thermoplastic material to form a composite material which is dimensionally stable. 35

Since isopropenyl acetate is a complicated to prepare compound, in comparison with a conventional based on Isopropenylacetat process another advantage is the fact that now a part of this complex compound is replaced while simultaneously improving the reaction conditions by simply produced carboxylic acids or carboxylic acid 40 de.

A reaction of the material to be acylated can take place in the liquid phase or via the gas phase, reaction temperatures of between 20 and 200 ° C. being possible. Even in the case of a small-sized material, a reaction time of 2 minutes is required to reach a sufficient degree of acylation, so a minimum reaction time is appropriately sized. A reaction time of more than 48 hours brings no increase in the degree of acylation, but can lead to an impairment of the material used by permanent contact with the reaction medium, which is why a maximum reaction time is 48 hours. 50

The process can be carried out at any pressure, in practice, a pressure in the range of 1 to 20 bar has proved to be favorable.

Any carboxylic acids, including polycarboxylic acids and carboxylic acids 55 with further functional groups, can be used as carboxylic acids, as long as acylation is possible. 4 AT 501 049 B1

Preference is given to using C 2 -C 22 -carboxylic acids. With increasing molecular weight or increasing size of carboxylic acids, these are less able to penetrate into the material to be acylated during the reaction and to react with hydroxyl groups in the interior of the material. Carboxylic acids having more than 22 carbon atoms, therefore, contribute little to a high degree of acylation, and therefore C2-C22 carboxylic acids are preferably used.

In a preferred variant of the process according to the invention, the mixture contains at least one C 2 -C 5 -alkanecarboxylic acid and / or one C 3 -C 6 -alkenecarboxylic acid and furthermore comprises a C 6 -C 22 -alkanecarboxylic acid and / or C 6 -C 22 -alkenecarboxylic acid. The low molecular weight C2-C5-alkanoic acid and / or a C3-C6-alkenecarboxylic acid on the one hand can cause a swelling of the material, which is more accessible in the swollen state for the acylating, resulting in higher degrees of acylation. The longer chain C6-C22 alkanecarboxylic acid and / or C6-C22 alkenecarboxylic acid, on the other hand, provide high hydrophobicity of the acylated material. 15

In this connection, it may be particularly advantageous to first add isopropenyl acetate and the C 2 -C 5 -alkanecarboxylic acid and / or the C 3 -C 6 -alkenecarboxylic acid and react with the material, and then add and react the C 6 -C 22 -carboxylic acid. In this variant, the interior of the material is first predominantly acylated, whereupon the acylation, especially in the region of the outer surface of the material, causes acylation of the material against the subsequent addition of the C6-C22-alkanecarboxylic acid and / or C6-C22-alkenecarboxylic acid created with a particularly apolar surface.

It may be advantageous if the mixture contains a) 20 to 80% by mass of isopropenyl acetate 25 and b) 80 to 20% by mass of one or more carboxylic acid (s) and / or one or more carboxylic anhydrides, because Such mixtures, when considered together, achieve optimum levels of acylation and hydrophobicity under mild reaction conditions. An inorganic acid, in particular hydrogen chloride, phosphoric acid or boric acid, can be used as the catalyst.

Alternatively, it is possible to use an organic acid or one of its salts, such as sodium acetate or an acyl halide. 35

The catalyst may alternatively be a base of the alkali type or one of its salts and / or a quaternary ammonium compound.

It is also possible to use a zeolite or a chlorosilane as a catalyst. 40

Finally, it is also possible that the catalyst is an aromatic sulfonic acid such as p-toluenesulfonic acid or a Lewis acid such as zinc chloride.

A concentration of the catalyst is suitably in the range of 0.002 to 5 moles 45 per kg of reaction mixture.

In order to achieve as complete acylation as possible, it is advantageous to continuously remove acetone formed during the reaction. Thus, in an alternative to this, acetone formed during the reaction may be left in the reaction mixture and / or acetone may be added. Such a procedure proves to be favorable if, after the reaction, an acylated material should be as free as possible of any acid residues, because these are then easier to remove. 55 The material used can be wood in the form of solid wood such as beams, boards, square timbers, 5 AT 501 049 B1

Veneers or similar solid wood workpieces are present. Likewise, the material can be present in the form of wood particles such as wood chips, wood fibers and / or wood flour or as pulp, in which cases a high degree of acylation can be achieved with short reaction times. 5

A method according to the invention can preferably also be used when the material is present as a fiber or as a fabric, in particular as a textile. Also cellulosic man-made fibers such as viscose fibers, cuprofibers, lyocell fibers or the like can be used. Incidentally, the material may be in the form of vegetable seed fibers, fruit fibers, leaf fibers or bast fibers such as jute, cotton, kenaf, coconut, flax, hemp, ramie, sisal or the like.

In the case of textiles and solid pieces of wood, in particular, it may be favorable if, in a first step, the material is wetted or impregnated with the mixture and, in a second step, the mixture is reacted with the material. This results in an acylation primarily of the surface of the material used, which is sufficient for specific applications.

The further object of the invention to provide an acylated material, which is hydrophobic and processable with a thermoplastic material to a dimensionally stable composite material, is achieved by a material according to claim 21.

The advantages of a material according to the invention can be seen, in particular, in the fact that a strongly hydrophobic material is provided in which at least a portion of originally present hydroxyl groups are esterified by means of isopropenyl acetate and at least one carboxylic acid or one carboxylic acid anhydride. By a proportionate Verersterung by means of carboxylic acid or carboxylic anhydride not only a higher degree of acylation and high hydrophobicity due, but also causes the material may be less polar than isopropenyl acetate treated material. A lowered polarity has an advantageous effect in the production of composites with thermoplastic polymers, because mixing of a less polar material according to the invention with polymers can be easier than previously and with less compatibilizer mass or, if necessary, no compatibilizer. The further object of the invention to provide a composite material which contains a cellulose and / or hemicellulose and / or lignin-containing material and a thermoplastic material and which is highly water-repellent and dimensionally stable and has a good fungal resistance is achieved by a composite material according to claim 22 , Advantageous variants of a composite material according to the invention are the subject matter of claims 23 40 to 27.

The advantages of a composite material according to the invention can be seen, in particular, in that, compared with composite materials in which cellulose-containing and / or hemicellulose and / or lignin-containing materials are used without prior modification or acylation, a water absorption of the composite material at room temperature by 35 to 40% is reduced. Furthermore, an 80% reduction in the likelihood of fungal infestation was found. Finally, composite materials according to the invention have a stiffness increased by 20% in comparison with approximately the same strength. Polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyoxymethylene, polyamide, polycarbonate, acrylonitrile-butadiene-styrene and / or polybutylene terephthalate are preferably provided as the thermoplastic material.

It has proven to be particularly favorable if the plastic is a poly-C 2 -C 5 -alpha-olefin 55 and / or a copolymer of a C 2 -C 5 -alpha-olefin and a different α-olefin with 6A 501 049 B1 2 to 18 carbon atoms and / or a cycloolefin-ethylene copolymer and / or an ethylene-vinyl acetate copolymer and / or a polypropylene homopolymer and / or a propylene random copolymer and / or a propylene block copolymer and / or a random Propylene block copolymer and / or isotactic polybutene-1 and / or 4-methyl-pentene-1-homo-5-polymeric and / or 4-methyl-1-pentene copolymers.

If a compatibilizer is used in a composite material according to the invention, it is advantageous if it consists of one or more constituents selected from the group consisting of polyalkylene glycols, C 1 -C 8 monoalkyl esters of polyalkylene glycols, maleic anhydride grafted onto polypropylene, polyolefin wax oxidates, ethylene / vinyl acetate copolymer waxes and grafted ethylene-vinyl acetate copolymers.

If a low density composite is required to produce lightweight molded articles, it is beneficial to have the thermoplastics and optionally compatibilizer (s) in a foamed form.

Composite materials according to the invention are excellently suitable for the production of products for the construction industry, for example windows, doors, cladding elements, bridle elements, terrace floors or roof elements and for furniture. In this case, it is advantageous for achieving a good weather resistance of the composites used if the acylated material comprises wood in the form of wood chips and / or wood fibers.

Further advantages of the invention will become apparent from the context of the description and the illustrated embodiments. 25

The invention is explained in more detail below with reference to examples.

Example 1 In a heated stirred reactor with a descending condenser and a condensate receiver, 0.5 kg of wood flour consisting of spruce, pine and larch flour in proportion (in% by mass) 85%: 15%: 5% with 3.5 kg of a mixture 50% by mass of butyric acid and 50% by mass of isopropenyl acetate. Then 37% aqueous HCl was added (0.3 mol HCl per kg reaction mixture). The reaction mixture thus prepared was stirred for 4 hours at 70 ° C. After the reaction, the chips were washed twice with acetone and once with methanol, followed by washing twice with water and then with a 0.005 molar aqueous sodium carbonate solution and finally with acid free of water. The acylated product was dried at 105 ° C to constant weight, after which a weight gain compared to the starting material (so-called weight percent gain or 40 WPG value) of 24% was obtained. The acylated wood flour was extruded in the 70:30 mass ratio with polyvinyl chloride; the extrusion products were highly water-repellent and exhibited high dimensional stability when used or stored in moist air.

Example 2 45

In a heated stirred reactor with descending condenser 2.8 liters of a mixture of isopropenyl acetate and propionic acid in a (mass) ratio of 2: 1 were submitted and 350 g of spruce chips and 0.2 mol / kg mixture of p-toluenesulfonic acid added. The chips used were acylated under reflux for 2.5 hours and washed and dried after the reaction analogous to Example 1. The WPG value of the chips was 22%. The chips showed greatly increased hydrophobicity and improved fungal resistance compared to products acylated exclusively with isopropenyl acetate.

A portion of the chips were then extruded with polypropylene (40% by weight chips and 60% by weight 55 polypropylene) to a shaped article. Another part of the chips was provided with the aid of 7% by weight of a resin, based on the mass of the chips, and pressed into a plate. Both the extruded molded article and the sheet were water repellent and had improved dimensional stability over conventional molded articles. 5 Example 3

In a heated stirred reactor (volume: 1 liter) with descending cooler 400 g of a mixture of 70% by mass isopropenyl acetate and 20% acetic acid and 10% by mass palmitic acid / stearic acid with 50 g chips (90% beech shavings and 10% pine chips) In the presence of 0.2 mol / kg of p-toluenesulfonic acid reacted for 7 hours. The acylated chips were washed after filtration with methanol and water and dried. The WPG value of the chips was 140%. The acylated chips had a significantly higher hydrophobicity in comparison with the chips according to Example 1. 15 Example 4

Wood fibers (50 g) purged with acetone were mixed with 30 ml of a mixture of isopropenyl acetate / propionic anhydride / propionic acid (mass ratio = 3: 2: 1) containing 0.5 mol / l of p-toluenesulfonic acid and allowed to stand at room temperature for 12 hours allowed to stand for a long time in a nitrogen atmosphere. Thereafter, the wood fibers were heated with dry, hot air for 10 minutes at 100 ° C and then washed with acetone and water and finally dried. A WPG value of the material thus obtained was 12%. From the wood fibers was finally pressed by conventional methods with resin and ammonium salt as a hardener a fiberboard. In comparison to conventional fiberboards, in which only acylated fibers were used with isopropenyl acetate, this had a markedly reduced susceptibility to water absorption.

EXAMPLE 5 In a heatable 1 liter reactor with circulation, 10 pieces of beech veneer boards (dimension: 50 × 120 × 1 mm) with a mixture of isopropenyl acetate / propionic acid / hexanoic acid (mass ratio = 4: 2: 1) in the presence of 0.02 were used with the aid of a special insert mol / kg mixture of benzenesulfonic acid at 110 ° C and reacted at a pressure of about 3 bar with slow circulation of the reaction mixture for 1 hour. From the thus obtained acylated 35 veneer boards a veneer board was pressed with glue. This was more water repellent than conventional veneer boards made from non-acylated veneer boards and had excellent resistance to fungi.

Example 6 40

In a heatable 1 liter reactor with circulation using a special insert four solid wood beams made of spruce (dimension: 20x120x20 mm) with isopropenyl acetate / acetic acid / dodecanoic acid (mass ratio = 4: 1: 1) and p-toluenesulfonic acid (0.02 mol / l Acylated under nitrogen, first with isopropenyl acetate and acetic acid for 4 hours at 45 90 ° C are reacted, after which dodecanoic acid is added and the temperature is increased to 120 ° C and reacted for an additional hour. After the reaction, the bars are allowed to stand in acetone for 15 minutes and then washed with water, 0.001 mol / L sodium carbonate solution and water again, and dried at 60 ° C. The Festholzbalken had a WPG value of 28% and water-repellent surfaces. 50

Example 7

A cotton fabric was wetted with a mixture of isopropenyl acetate / propionic acid / oleic acid (mass ratio = 2: 1: 0.2) and in the presence of potassium carbonate (0.2 mol / l) 55 and methyltrioctylammonium chloride (0.2 mol / l), precipitated with padding , and eight minutes

Claims (27)

8 AT 501 049 B1 heated to 100 ° C while purging with nitrogen. The textile thus treated had a WPG value of 12%. Due to its water-repellent properties, the acylated textile is particularly suitable for health and sports articles. 5 Example 8 In a heated 500 ml stirred reactor with descending condenser, 20 g of hemp fiber washed with acetone were mixed with 300 ml of a mixture of isopropenyl acetate and glacial acetic acid (mass ratio = 1: 2) in the presence of p-toluenesulfonic acid (0.08 mol / l) and 15 ml Acetone at 70 ° C io for 2 hours under reflux and acylated in an argon atmosphere. After the reaction, the hemp fibers were washed and dried as described in Example 1. A WPG value of the hemp fibers was 18%. The fibers treated according to the invention could be extruded together with wood shavings and polyethylene to form a composite body without the need for a compatibilizer. EXAMPLE 9 In a heated stirred reactor (volume: 2 liters) with descending condenser, 500 g of kraft lignin with isopropenyl acetate / propionic acid (mass ratio = 1: 1) in the presence of 20 ZnCl 2 as catalyst (0.05 mol / l) were used and refluxed acylated for three hours. After cooling, the reaction mixture was carefully poured into water and the solid was filtered off, washed and dried. The acylated lignin was used as a binder in wood composites, which had high strength and water resistance due to the acylated lignin. EXAMPLE 10 A cotton fabric was maintained at 90 ° C. with isopropenyl acetate / maleic anhydride (mass ratio = 1: 2) in the presence of p-toluenesulfonic acid (0.02 mol / l) for 20 minutes. The textile thus treated had bactericidal properties. 1. A process for the acylation of a particular cellulose and / or hemicellulose and / or lignin-containing material, wherein the material with a mixture containing a) 5 to 95% by mass isopropenyl acetate and b) 95 to 5% by mass of one or more carboxylic acid (n) and / or one or more carboxylic anhydrides (s) 40 is reacted at a reaction temperature of 20 to 200 ° C and a residence time of 2 minutes to 48 hours in the presence of a catalyst. 2. The method of claim 1, wherein is reacted at a reaction pressure of 1 to 20 bar. 45 3. The method of claim 1 or 2, wherein the carboxylic acid or the carboxylic acids C2-C22 carboxylic acid (s) is or are. 4. The method according to any one of claims 1 to 3, wherein the mixture contains at least one C2-C5- 50 alkanecarboxylic acid and / or a C3-C6-alkenecarboxylic acid and further comprises a C6-C22-alkanecarboxylic acid and / or C6-C22-alkenecarboxylic acid. 5. The method of claim 4, wherein first isopropenyl acetate and the C2-C5 alkane carboxylic acid and / or the C3-C6 alkenecarboxylic acid are added and reacted with the material and then the C6-C22 carboxylic acid is added and reacted. 55 9 AT 501 049 B1 6. The method according to any one of claims 1 to 5, wherein the mixture contains a) 20 to 80% by mass of isopropenyl acetate and b) 80 to 20% by mass of one or more carboxylic acid (s) and / or one or more carboxylic anhydrides (s) , 5 7. The method according to any one of claims 1 to 6, wherein the catalyst is an inorganic acid, in particular hydrogen chloride, phosphoric acid or boric acid. 8. The method according to any one of claims 1 to 6, wherein the catalyst is an organic acid or one of its salts, such as sodium acetate or an acyl halide. 9. The method according to any one of claims 1 to 6, wherein the catalyst is a base of the alkali type or one of its salts and / or a quaternary ammonium compound. 10. The method according to any one of claims 1 to 6, wherein the catalyst is a zeolite or a chlorosilane. 11. The method according to any one of claims 1 to 6, wherein the catalyst is an aromatic sulfonic acid such as p-toluenesulfonic acid or a Lewis acid such as zinc chloride. 20 12. The method according to any one of claims 1 to 11, wherein a concentration of the catalyst is 0.002 to 5 mol per kg of reaction mixture. 13. The method according to any one of claims 1 to 12, wherein during the reaction resulting 25 acetone is removed continuously. 14. The method according to any one of claims 1 to 12, wherein acetone formed during the reaction is left in the reaction mixture and / or acetone is added. 15. The method according to any one of claims 1 to 14, wherein the material is present as wood in the form of solid wood such as beams, boards, squared timbers, veneers or the like massive wood workpieces. 16. The method according to any one of claims 1 to 14, wherein the material is in the form of wood particles 35 such as wood chips, wood fibers and / or wood flour or as pulp. 17. The method according to any one of claims 1 to 14, wherein the material is present as a fiber or as a fabric, in particular as a textile. 18. The method according to any one of claims 1 to 14, wherein the material in the form of vegetable seed fibers, fruit fibers, leaf fiber or bast fibers such as jute, cotton, kenaf, coconut, flax, hemp, ramie, sisal or the like is present. 19. The method according to any one of claims 1 to 14, wherein the material is in the form of cellulosic-looking synthetic fibers such as viscose fibers, cuprofibres, lyocell fibers or the like. 20. The method according to any one of claims 1 to 19, wherein in a first step, the material is wetted or impregnated with the mixture and in a second step, a conversion 50 tion of the mixture with the material. 21. Acylated material obtainable according to one of claims 1 to 20. 22. Composite comprising (in% by mass) a) 30 to 90% of a material obtainable according to one of claims 1 to 20, 55 1 Ο 501 049 Β1 b) 70 to 10% of a thermoplastic, c) optionally 0.3 to 20 % of a compatibilizer, d) optionally 3 to 10% of a flame retardant, e) optionally 0.1 to 2% of a pigment, 5 f) optionally 0.1 to 2% of a stabilizer. 23. The composite of claim 24, wherein the thermoplastic comprises polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyoxymethylene, polyamide, polycarbonate, acrylonitrile butadiene styrene, and / or polybutylene terephthalate. 10 24. A composite material according to claim 22 or 23, wherein the plastic is a poly-C2-C5-α-olefin and / or a copolymer of a C2-C5-α-olefin and a different α-olefin having 2 to 18 carbon atoms and / or a cycloolefin-ethylene copolymer and / or an ethylene-vinyl acetate copolymer and / or a polypropylene homopolymer and / or a βίοι 5 tistisches propylene copolymer and / or a propylene block copolymer and / or a stati cal propylene Block copolymer and / or isotactic polybutene-1 and / or 4-methyl-1-pentene homopolymer and / or 4-methylpentene-1-copolymers. 25. A composite according to any one of claims 22 to 24, wherein the compatibilizer of 20 one or more constituents selected from the group consisting of polyalkylene glycols, Ci-Ce monoalkyl esters of polyalkylene glycols, maleic anhydride grafted onto polypropylene, Polyolefinwachsoxidate, ethylene-vinyl acetate copolymer waxes and grafted ethylene-vinyl acetate copolymers. 26. A composite material according to any one of claims 22 to 25, wherein thermoplastics and, where appropriate, compatibilizer (s) are present in a foamed form. 27. A composite material according to any one of claims 22 to 26, wherein the material of component a) comprises wood in the form of wood chips and / or wood fibers. 30 No drawing 35 40 45 50