EP3339508B1 - Process for the treatment of materials containing fibers - Google Patents

Description

The invention relates to a method for processing materials containing fibers and to materials and systems obtainable with this method. The invention also relates to the use of a mixture containing a polymer for processing a material containing fibers, the use of dimethyl sulfoxide as an antioxidant in the processing of paper and the use of ionic liquids as an antimicrobial agent for the processing of paper.

Organic materials containing fibers, in particular paper, experience mechanical destabilization in that the macromolecules forming the fiber, such as cellulose macromolecules, are broken down over time. Especially in the case of paper, this can lead to the paper being so destabilized that the books made from this paper can no longer be used. The problems of destabilization, especially due to aging, do not only exist with paper and cellulose-containing materials in general, such as wood, but also generally represent a problem for materials containing fibers. To counteract this problem, appropriate processing methods are used for the material containing fibers needed. Paper, in particular printed paper in books, as a material containing fibers, places the highest demands on the processing method, which is why the further discussion should take place using the example of paper, in particular printed paper.

In the case of documents made of paper, for example old manuscripts or old books, the destabilization can lead to the paper becoming brittle. This paper must be strengthened to reduce its brittleness.

When processing paper, especially printed paper in books, it is desirable that the processing method meet several requirements. On the one hand, the processing method should not only allow single sheet processing. Rather, the process should be able to process multiple sheets at once. The pages should not stick together. In addition, if possible, the method should not damage the cover of a book and / or the binding or spine gluing of the sheets. In this way, the method can be carried out more economically, since several sheets can be processed at the same time or entire books can be processed at once and there is no need to separate the sheets from books. Furthermore, the process should not attack the paper in any other way, in particular the paper should not swell irreversibly. The process should also not wash out the ink and / or printing inks on the paper to be processed. At the same time, however, it is desirable that the processing of the paper does not only take place superficially, but ideally begins throughout the paper.

Various methods have been developed for processing paper. A good strengthening of paper can be achieved, for example, by splitting the damaged paper and gluing it back together with a thin intermediate layer and a special adhesive that contains cellulose ether and deacidifying agent. However, this processing is associated with a high level of manual effort and is therefore cost-intensive.

A process for strengthening paper is also known in which the paper is impregnated with acrylic acid derivatives which are polymerized by exposure to gamma rays. Irradiation with gamma rays, however, leads to further damage to the paper, as a result of the impregnation with acrylic acid, paints and inks on the paper at least partially bleed, and residual monomers remaining in the paper lead to an odor nuisance. In addition, this process can only be combined with other conventional means of paper restoration with difficulty.

The processing of paper by lamination is also known, a thin polymer film or a thin stabilizing paper being applied to one or both sides of the paper. With this method, which is carried out with individual sheets, the processed paper stack often no longer fits into the book cover after processing due to the increasing paper thickness. It also changes the feel and appearance of the paper. Furthermore, the contrast decreases due to the layers applied. Furthermore is this process can only be combined with other conventional means of paper restoration with difficulty.

A well-known method for processing paper is the so-called Wiener method, which is in the EP 0 273 9602 A2 is described. In this process, the material to be processed is soaked in an aqueous solution that contains methyl cellulose to strengthen the paper. The processing solution is then pumped out, residues of the processing solution are allowed to drip off the processed paper, and the paper is then shock-frozen and freeze-dried. The main disadvantage of this method is that book covers are damaged, which is why the pages of the book have to be removed before processing. In addition, a derivatized polymer must be used with methyl cellulose.

The DE 100 57 554 A1 describes a process in which the paper to be processed is processed with a silylated polymer derivative such as silylated cellulose, which is dissolved in a non-polar solvent. The silyl groups are then split off by the action of moisture or water. The disadvantage of this process is the compulsory use of derivatized polymers.

The EP 3 072 933 A1 describes alkaline nanoparticles containing at least one hydroxide or carbonate or an organic compound of an alkaline earth metal and optionally a hydrophilic cellulose derivative and a stabilizing outer layer made of hydrophobic polymers for deacidifying and strengthening cellulose-based artifacts. However, the nanoparticles must first be synthesized.

The EP 0 285 227 A1 describes a process for the preservation of paper sheets or paper webs, in which the solution of a deacidifying agent and a polymeric reinforcing agent for the paper in an organic solvent or in a mixture of organic solvents is sprayed onto one surface of the paper, and one is sprayed onto the other surface of the paper exerts strong suction to pull the solution through the paper and also to at least partially dry the treated paper.

In the U.S. 3,529,925 A describes a process for inter-fiber bonding of cellulose fiber webs, comprising contacting the cellulose fiber web with a solution of dimethyl sulfoxide which contains about 3 to 30% by weight of nitrogen dioxide for a Duration of about 10 to 300 seconds, washing the web to remove the solution, and drying the cellulosic fiber web.

The WO 2014/201544 A1 describes antimicrobial polymers which impart prolonged antimicrobial activity to a surface or in a solution, the polymers comprising as repeating monomers a polymerizable cyclic unit which forms part of the polymer backbone and an antimicrobial unit such as a quaternary ammonium unit in the side chain.

The methods known in the prior art have various disadvantages such as the necessary single sheet processing, sticking of pages, bleeding of paints and / or inks, odor nuisance, strong increase in paper thickness, use of derivatized polymers, lack of compatibility with other conventional means of paper restoration and Damage to book covers and / or spine gluing.

The object of the invention is therefore to provide a method for processing, in particular for strengthening, material containing fibers, in particular paper, which at least partially overcomes one or more disadvantages of the methods known from the prior art. In particular, it is desirable to have a method by which damaged paper can be mass processed. The paper to be processed should not be damaged any further. In particular, the paper to be processed should be strengthened. Any inks and printing inks on the paper to be processed should not bleed. Furthermore, the bindings and / or the paper backing should not be damaged by the process. In addition, it is desirable if substances that are easy to obtain, such as polymers, which in particular are not derivatized, can be used in the process.

This object is achieved according to the invention by the method according to claim 1, the material containing fibers according to claim 19, the system according to claim 20, the use according to claim 21, the use according to claim 23 and the use according to claim 24.

Advantageous refinements are specified in the subclaims and are explained in detail below.

1. a. Bereitstellen eines Gemischs enthaltend (i) mindestens ein Polymer ausgewählt aus der Gruppe bestehend aus Cellulose, alpha-Cellulose, mikrokristalline Cellulose, Zellstoff, Hemicellulose, Viskose, Chitin, Lignin, Chitosan, Alginat, Stärke, Seide, natürliche Seide, Seidenbiopolymere, Polyvinylalkohol, Polyvinylacetat, Polyurethane, Polyamide, Proteine, Polymere oder Copolymere auf Basis von Acrylsäure und/oder ihren Ester- und/oder Amid-Derivaten, Methacrylsäure und/oder ihren Ester- und/oder Amid-Derivaten, Vinylacetat, Itaconsäure, Maleinsäure, Fumarsäure, Acryloxypropionsäure, Methacryloxypropionsäure, Styrolsulfonsäure, Ethylmethacrylat-2-sulfonsäure, 2-Acrylamido-2-methylpropansulfonsäure, Phosphoethylmethacrylat, Celluloseether und Mischungen davon, und (ii) ein polar aprotisches Lösemittel,
2. b. in Kontakt bringen des zu bearbeitenden Materials mit dem in Schritt a. bereitgestellten Gemisch, um eine Mischung aus dem Material und dem in Schritt a. bereitgestellten Gemisch zu erhalten,
3. c. Behandeln der in Schritt b. erhaltenen Mischung, so dass sich mindestens ein Teil des Polymers an den Fasern des Materials anlagert, dadurch gekennzeichnet, dass die Behandlung der Mischung in Schritt c. das in Kontakt Bringen der Mischung mit einem unpolaren Lösemittel umfasst oder daraus besteht.

The method according to the invention for processing a material containing fibers, the material containing cellulose, microcrystalline cellulose, cellulose, hemicellulose, viscose, chitin, chitosan, alginate, starch, lignin, polyvinyl alcohol, proteins or mixtures thereof comprises the following steps:

1. a. Providing a mixture containing (i) at least one polymer selected from the group consisting of cellulose, alpha-cellulose, microcrystalline cellulose, cellulose, hemicellulose, viscose, chitin, lignin, chitosan, alginate, starch, silk, natural silk, silk biopolymers, polyvinyl alcohol, Polyvinyl acetate, polyurethanes, polyamides, proteins, polymers or copolymers based on acrylic acid and / or its ester and / or amide derivatives, methacrylic acid and / or its ester and / or amide derivatives, vinyl acetate, itaconic acid, maleic acid, fumaric acid, Acryloxypropionic acid, methacryloxypropionic acid, styrene sulfonic acid, ethyl methacrylate-2-sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, phosphoethyl methacrylate, cellulose ether and mixtures thereof, and (ii) a polar aprotic solvent,
2. b. bringing the material to be processed into contact with that in step a. provided mixture in order to produce a mixture of the material and the in step a. to obtain the mixture provided,
3. c. Treating the in step b. obtained mixture, so that at least a part of the polymer is deposited on the fibers of the material, characterized in that the treatment of the mixture in step c. comprises or consists of bringing the mixture into contact with a non-polar solvent.

Surprisingly, it has been found that materials containing fibers can be processed very efficiently, effectively and safely for material strengthening and / or surface smoothing, in particular with massive material application, using the method according to the invention.

A particular advantage of the method according to the invention is that, by using a polar aprotic solvent, non-derivatized polymers such as cellulose can also be used as the at least one polymer in the method according to the invention. Furthermore, by using a polar aprotic solvent, mixtures, in particular solutions, with a low viscosity can be produced which are particularly suitable for processing books or similar substrates.

Surprisingly, with the method according to the invention, sticking of the pages can be avoided despite the use of polymers. The use of the polar aprotic solvent also allows a wide range of options for treating the mixture of the material to be processed containing fibers and the mixture, so that at least part of the polymer is deposited on the fibers of the material containing fibers. Furthermore, the method according to the invention can be combined with other methods, in particular deacidification methods.

When "dissolving" is mentioned here or elsewhere, in particular that a substance dissolves in a solvent, this can in particular mean that a solution of the substance in the solvent can be produced which is at least 0.5 Weight%, in particular at least 1 weight%, 2 weight%, 3 weight%, 4 weight%, 5 weight%, 6 weight%, 7 weight%, 8 weight%, 9 weight% or at least 10% by weight, and at most 25% by weight, in particular at most 20% by weight, 15% by weight, 14% by weight, 13% by weight or at most 12% by weight, each based on the total weight of the solution, of the substance.

If here or elsewhere the term "accumulation", in particular the accumulation of a substance on another substrate, can mean in particular the precipitation, crystallization, deposition, growth and / or settling, in particular on the other substrate . The polymer can be completely or partially attached to the material containing fibers, in particular to the fibers of the material containing fibers. If the polymer only partially attaches to the fibers of the material containing fibers, a residual amount of polymer remains in the mixture. The fibers of the material containing fibers are preferably completely or partially sheathed by attachment. This can strengthen the fiber.

“Derivatized polymers” can in particular be those polymers which have been obtained by chemical modification of another polymer. The derivatization can also be reversible, so that the original polymer can be recovered. For example, derivatized polymers are made from naturally occurring polymers such as cellulose or starch. For example, the derivatized polymer methylcellulose can be obtained from nonderivatized cellulose by chemical modification. Further examples of non-derivatized polymers are starch, chitosan, chitin, lignin, viscose, cellulose, silk and alginate. Various chemical modifications can be used for the derivatization. The derivatization can for example by partial or complete alkylation, partial or complete acylation, partial or complete silylation or partial or complete sulfonylation can be achieved.

"Material containing fibers" is also referred to below as "fiber-containing material" or "fiber-containing material".

Steps a. to c. of the method according to the invention are advantageously carried out in the order given.

The most varied of fiber-containing materials can be processed with the method according to the invention. The fiber-containing material can contain a polymer with at least one polar group, in particular in a proportion of 50 wt.%, 60 wt.%, 70 wt.%, 80 wt.%, 90 wt.%, 95 wt.%, 99 wt .%, or consist of it. The at least one polar group can be contained in the polymer backbone and / or be linked to the polymer backbone as a side chain. If several polar groups are contained, these can be the same or different. Polar groups are known to the person skilled in the art. Examples of polar groups include the hydroxyl group, acid groups such as the carboxyl group and the sulfonic acid group, the amide group, the amine group, the thiol group, the ether group, in particular the C1-C4- Alkyl ether group, the ester group and the urethane group. The fiber-containing material contains cellulose, microcrystalline cellulose, pulp, hemicellulose, viscose, chitin, chitosan, alginate, starch, lignin, polyvinyl alcohol, proteins or mixtures thereof. Further components of the fiber-containing material can be further polymers, in particular further polymers with at least one polar group, but also, for example, fillers such as calcium carbonate or pigments such as titanium dioxide. In particular, the fiber-containing material can be a cellulose-containing material, in particular paper, cardboard, cardboard, textiles or wood. According to a preferred embodiment of the invention, the fiber-containing material is paper, in particular paper sheets. Examples of paper are typewriter paper, printer paper, magazine paper, newsprint, and book paper.

In the method according to the invention, a mixture containing a polymer is provided. Various polymers can be used as the polymer. The polymer can be a copolymer or a homopolymer. The polymer can in particular have a mass average molecular weight Mw of 1000 to 10000000 g / mol, in particular from 3000 to 1000000 g / mol, from 5000 to 500000 g / mol or from 10,000 to 100,000 g / mol, exhibit. The polymer can also contain at least one polar group. The at least one polar group can be contained in the polymer backbone and / or be linked to the polymer backbone as a side chain. If several polar groups are contained, these can be the same or different. Polar groups are known to the person skilled in the art. Examples of polar groups include the hydroxyl group, acid groups such as the carboxyl group and the sulfonic acid group, the amide group, the amine group, the thiol group, the ether group, in particular the C1-C4- Alkyl ether group, the ester group and the urethane group. In particular, the polymer can have at least one hydroxyl group, at least one amine group, at least one acid group, in particular a carboxyl group, at least one amide group, at least one thiol group, at least one ether group, in particular a C1- C4-alkyl ether group, at least one ester group and / or at least one urethane group, in particular at least one hydroxyl group. The polymer is selected from the group consisting of cellulose, alpha-cellulose, microcrystalline cellulose, cellulose, hemicellulose, viscose, chitin, lignin, chitosan, alginate, starch, silk, natural silk, silk biopolymers, polyvinyl alcohol, polyvinyl acetate, polyurethanes, polyamides, proteins , Polymers or copolymers based on acrylic acid and / or its ester and / or amide derivatives, methacrylic acid and / or its ester and / or amide derivatives, vinyl acetate, itaconic acid, maleic acid, fumaric acid, acryloxypropionic acid, methacryloxypropionic acid, styrene sulfonic acid, ethyl methacrylate -2-sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, phosphoethyl methacrylate, cellulose ethers and mixtures thereof. Preferably the polymer is a nonderivatized polymer such as cellulose and / or viscose. The polymer preferably contains at least one hydroxyl group.

In particular, the polymer can be selected from the group consisting of cellulose, alpha cellulose, microcrystalline cellulose, cellulose, hemicellulose, viscose, chitin, lignin, chitosan, alginate, starch, silk, silk biopolymers, polyvinyl alcohol and mixtures thereof. The polymer is preferably selected from the group consisting of cellulose, alpha-cellulose, microcrystalline cellulose, cellulose, silk, silk biopolymers, viscose and mixtures thereof. The polymer is advantageously selected from the group consisting of cellulose, alpha-cellulose, microcrystalline cellulose, cellulose, viscose and mixtures thereof. According to a preferred embodiment, the polymer is alpha-cellulose. According to a further preferred embodiment, the polymer is viscose, in particular essentially non-derivatized viscose. It has been shown that fiber-containing materials can be processed particularly well with the aforementioned polymers. In particular, processing with the above polymers made good Strengthening, especially of cellulosic materials such as paper, cardboard, cardboard and wood can be achieved.

The polymer can in particular be used in the form of fibers.

Viscose is made up of regenerated cellulose in particular. Viscose can in particular be in the form of fibers. Viscose can in particular be a regenerated cellulose fiber, as it is in FIG EP 2 546 396 (see in particular paragraphs [0026], [0028], [0029], [0030], [0031], [0032], [0033], [0034], [0035], [0036], [0037] and / or [0038]) is described. Accordingly, the viscose can be in the form of fibers which have several legs and in which at least one leg differs from the other legs in terms of its length. In particular, it can be asymmetrical cellulose fibers. The titer of the asymmetrical cellulose fibers can be from 1.3 dtex to 10 dtex, in particular 3.3 dtex. The titer indicates the fineness, with 1 dtex corresponding in particular to a weight of one gram per 10,000 meters of cellulose fibers.

Silk biopolymers can, in particular, be silk biopolymers, as described in FIG WO 2014/037453 or in the WO 2011/113446 are described. Correspondingly, the silk biopolymers can in particular consist of polypeptides which are essentially built up from one or more repeating polypeptide units and one or more non-repeating polypeptide units. The repeating polypeptide units can in particular contain oligoalanine units. The repeating polypeptide units, the modules A ^C (GPYGPGASAAAAAAGGYGPGCGQQ), A ^K (GPYGPGASAAAAAAGGYGPGKGQQ), C ^C (GSSAAAAAAAASGPGGYGPENQGPCGPGGYGPGGP), C ^K1 (GSSAAAAAAAASGPGGYGPENQGPKGPGGYGPGGP), C ^K2 (GSSAAAAAAAASGPGGYGPKNQGPSGPGGYGPGGP) or C ^KC (GSSAAAAAAAASGPGGYGPKNQGPCGPGGYGPGGP) may comprise or consist thereof, wherein the sequences given in brackets represent amino acids in one-letter code, as it is, for example, in the book " Enzymes - A Practical Introduction to Structure, Mechanism, and Data Analysis ", 2nd Edition by Robert A. Copeland, Wiley-VCH, 2000 , is described in table 3.1 on page 45. The non-repeating polypeptide units can be selected from the WO 2014/037453 , in particular on page 16, described "non-repetitive (NR)" units NR3, NR4, NR5, NR6 or in the WO 2014/037453 be selected variants thereof described.

The polymer in step a. of the method according to the invention can be the same as or different from the polymer with at least one polar group, which can be contained in the fiber-containing material. For example, a cellulose-containing material can be brought into contact as a fiber-containing material with a mixture which also contains cellulose as a polymer. Likewise, however, a cellulose-containing material can also be brought into contact as a fiber-containing material, for example with a mixture which contains polyvinyl alcohol as a polymer. If the polymer contained in the mixture contains a polar group, the polar group of the polymer with at least one polar group which can be contained in the fiber-containing material and the polar group of the at least one polymer contained in the mixture can be the same or different. For example, the fiber-containing material can be a cellulosic material and the polar polymer can be a polyurethane.

A wide variety of solvents can be used as polar aprotic solvents in the process according to the invention. In polar aprotic solvents, the molecules can have a dipole moment and / or the polar aprotic solvent can be composed of ions. Furthermore, polar aprotic solvents can be free of groups, in particular polar groups, from which protons can be split off. Examples of such groups are the OH group, acid groups such as the carboxyl group, the sulfonic acid group and hydrogen halide groups, the thiol group, and primary and secondary amines. Particularly suitable polar aprotic solvents are ketones, lactones, lactams, in particular N-alkylated lactams, nitriles, tertiary carboxamides, urea derivatives, in particular alkylated urea derivatives, sulfoxides, sulfones, carbonic acid esters, ionic liquids and / or mixtures thereof.

Examples of ketones are acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, cyclohexanone and their C1 to C4 alkylated derivatives.

Examples of lactones are propriolactone, gammabutyrolactone, deltavalerolactone, epsiloncaprolactone and their C1- to C4-alkylated derivatives.

Examples of lactams are propiolactam, gammabutyrolactam and their C1- to C4-alkylated derivatives.

Examples of alkylated lactams are N-methyl-propiolactam, N-methyl-2-pyrrolidone and their C1- to C4-alkylated derivatives.

Examples of nitriles are acetonitrile, propionitrile, butyronitrile, valeronitrile and their C1 to C4 alkylated derivatives.

Examples of tertiary carboxamides such as dimethylformamide, dimethylacetamide, dimethylpropionamide and their C1- to C4-alkylated derivatives.

Examples of urea derivatives, in particular alkylated urea derivatives, are dimethylpropylene urea, tetramethylurea and their C1 to C4 alkylated derivatives.

Examples of sulfoxides are dimethyl sulfoxide, ethyl methyl sulfoxide, diethyl sulfoxide and their C1 to C4 alkylated derivatives.

Examples of sulfones are sulfolane, ethylmethyl sulfone and their C1 to C4 alkylated derivatives.

Examples of carbonic acid esters are dimethyl carbonate, ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate and their C1 to C4 alkylated derivatives.

Examples of ionic liquids are given below.

The polar aprotic solvent is preferably selected from the group consisting of acetonitrile, dimethylformamide, dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, acetone, gammabutyrolactone, N-methyl-2-pyrrolidone, tetramethylurea, dimethylpropyleneurea, sulfolane, dimethyl carbonate ionic liquids and mixtures thereof In particular, the polar aprotic solvent is selected from the group consisting of dimethylacetamide, dimethyl sulfoxide, acetonitrile, ionic liquids and mixtures thereof. Polar aprotic solvents that are a mixture of an ionic liquid and at least one of acetonitrile, dimethylformamide, dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, acetone, gammabutyrolactone, N-methyl-2-pyrrolidone, tetramethylurea, dimethylpropyleneurea, sulfolane, dimethyl carbonate and contain ethylene ionic liquid.

The polar aprotic solvent can contain one or more ionic compounds, for example salts, inorganic salts and / or ionic liquids, or in particular consist of one or more ionic liquids.

Inorganic salts are, for example, lithium fluoride, lithium chloride, lithium bromide, lithium iodide, sodium fluoride, sodium chloride, sodium bromide, sodium iodide, potassium fluoride, potassium chloride, potassium bromide or potassium iodide, in particular lithium chloride or lithium bromide and mixtures thereof. Inorganic salts can be present in an amount of 1 to 10% by weight, 3 to 8% by weight or 4 to 6% by weight, based in each case on the total amount of polar aprotic solvent and inorganic salt or inorganic salts. Accordingly, a polar aprotic solvent can be, for example, dimethylacetamide containing 5% by weight of lithium chloride.

Particularly good results can be achieved if the polar aprotic solvent contains an ionic liquid. Suitable ionic liquids are described in detail below. The polar aprotic solvent is preferably a mixture of an ionic liquid and at least one of dimethylacetamide, dimethyl sulfoxide and acetonitrile. According to a preferred embodiment, the polar aprotic solvent is a mixture of an ionic liquid and dimethylacetamide or dimethyl sulfoxide. According to a further preferred embodiment, the polar aprotic solvent is a mixture of an ionic liquid and dimethylacetamide. According to a further preferred embodiment, the polar aprotic solvent is a mixture of an ionic liquid and dimethyl sulfoxide.

The abovementioned polar aprotic solvents can be used to produce mixtures, in particular solutions, with the most varied of polymers. In particular, many poorly soluble polymers, in particular polymers containing at least one polar group, can dissolve well in these polar aprotic solvents. If the polar aprotic solvent contains one or more ionic compounds, polymers containing at least one polar group, in particular cellulose, can be better dissolved in them. In this way, mixtures, in particular solutions, with a content of, for example, 0.5 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt. , 7% by weight, 8% by weight, 9% by weight, 10% by weight, 11% by weight, 12% by weight, 13% by weight, 14% by weight or 15% by weight, each based on the Total weight of the mixture, of polymer. This allows the concentration of the polymer to be widened Area to be adapted to the needs of the fiber-containing material to be processed, which allows effective processing of the fiber-containing material.

The polar aprotic solvent can contain or consist of one or more ionic liquids. Particularly suitable ionic liquids are organic salts, the ions of which hinder the formation of a stable crystal lattice through charge delocalization and steric effects. Ionic liquids have the particular advantage that many poorly soluble polymers such as cellulose dissolve well in them. Furthermore, ionic liquids can be modified well and thus adapted to different requirements.

If the polar aprotic solvent contains an ionic liquid, the ionic liquid contains in particular a cation selected from a 1,3-dialkylimidazolium cation, an alkylpyridinium cation, a tetraalkylammonium cation and a phosphonium cation, and an anion selected from fluoride, chloride, bromide, iodide, formate, Acetate, propionate, butyrate, hydrogen sulfate, tosylate, trifluoromethanesulfonate, bis (trifluoromethanesulfonyl) imide, hexafluorophosphate, tetrafluoroborate, benzoate, glycolate, thioglycolate, lactate and glycinate, or it consists of them. The ionic liquid preferably contains a dialkylimidazolium cation and an anion selected from chloride, bromide and acetate, or it consists of these. The alkyl groups of the dialkylimidazolium cation can in particular be identical or different. The alkyl groups of the dialkylimidazolium cation can in particular be C1 to C10, in particular C1 to C5 alkyl groups. The alkyl groups of the dialkylimidazolium cation, independently of one another, can preferably be selected from the group consisting of methyl, ethyl, propyl and butyl. According to a preferred embodiment, the ionic liquid contains 1-butyl-3-methylimidazolium chloride and / or 1-butyl-3-methylimidazolium acetate or consists thereof.

The cations and anions listed above have the particular advantage that many polymers, in particular also sparingly soluble polymers such as cellulose, are readily soluble in ionic liquids that contain or consist of these cations and anions. Furthermore, the acetate anion in particular has the advantage that the pH value of fiber-containing materials with an acidic pH value is brought into contact with a mixture in which the polar aprotic solvent contains an ionic liquid containing acetate anions can be raised. This is particularly important when processing paper, since by increasing the pH value in the paper, the degradation of the cellulose fibers can be slowed down or even prevented.

The mixture containing at least one polymer and a polar aprotic solvent is preferably a homogeneous mixture, in particular a solution. Alternatively, the polymer in the mixture can be partially dissolved or swollen by the polar aprotic solvent.

Providing a mixture containing a polar aprotic solvent has the advantage, inter alia, that mixtures, in particular solutions, with a low viscosity can be obtained. Such mixtures, in particular solutions, are particularly suitable for processing fiber-containing materials, in particular cellulose-containing materials such as paper. The mixture, in particular the solution with which the fiber-containing material to be processed is brought into contact, can in particular have a viscosity of 0.01 to 100 mPas, preferably 0.1 to 70 mPas, preferably 0.5 to 50 mPas, more preferably 1 to 30 mPas, even more preferably 1 to 15 mPas. Mixtures, in particular solutions, with such viscosities are particularly suitable for processing fiber-containing materials, especially cellulose-containing materials such as paper, since they can penetrate deep into the fiber-containing material and thus not only allow superficial deposition of the polymer. Methods for determining the viscosity of mixtures, in particular of solutions, are known to the person skilled in the art. In particular, the viscosity can be determined at 25 ° C. using a "Gemini" rotary viscometer from Bohlin.

Bringing the fiber-containing material into contact with the mixture containing at least one polymer and a polar aprotic solvent can be carried out in various ways. For example, the fiber-containing material, in particular paper, can be sprayed or coated with the mixture, or the fiber-containing material, in particular paper, can be soaked in the mixture. The fiber-containing material is advantageously soaked in the mixture. If the fiber-containing material is soaked in the mixture, this can be for a period of 0.1 to 10 minutes, in particular 0.2 to 8 minutes, 0.2 to 7 minutes, 0.4 to 6 minutes, 0.5 to 5 minutes Minutes, 0.5 to 4 minutes, 0.5 to 3 minutes, or 0.5 to 2 minutes. As a result, the at least one polymer can penetrate well into the fiber-containing material, so that it can easily attach itself to the fibers of the material. The soaked fiber-containing material can then be rinsed off with a polar aprotic solvent, in particular with dimethylacetamide and / or dimethyl sulfoxide, in particular for a period of 10 to 60 seconds, 20 to 50 seconds or 25 to 40 seconds. Rinsing can remove excess polymer.

The method according to the invention comprises the step of treating the mixture of the fiber-containing material and the mixture containing at least one polymer and a polar aprotic solvent, so that at least part of the polymer is deposited on the fibers of the material. The mixture can be treated in different ways. The treatment of the mixture in step c. is selected from bringing the mixture into contact with a non-polar solvent.

Examples of ionic compounds are salts or polymers with at least one ionic side group. Salts consist in particular of at least one cation and at least one anion, it being possible for the cation to be selected from cations which are selected from metals from the group consisting of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba , Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag , Au, Zn, Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, and wherein the anion can be selected from anions which are derived from elements of the group consisting of F, Cl, Br, I , O, S, Se, Te. Further examples of cations are ammonium ions. Further examples of anions are hydride, hydroxide, phosphates, phosphites, sulfates, sulfites, sulfides and carboxylates such as formate, acetate, propionate, salicylate and benzoate. The salt can in particular contain ammonium sulfate or potassium sulfate or a mixture thereof. Examples of polymers with ionic side groups are polymers with at least one deprotonated acid group, in particular a deprotonated carboxyl group such as deprotonated polyacrylate, deprotonated polymethacrylate, polymers with at least one quaternary ammonium compound such as quaternized polydimethylaminoethyl methacrylate. The mixture can be brought into contact with the ionic compound by adding the salt directly or in the form of a solution, in particular an aqueous solution.

Examples of non-ionic compounds are water, alcohols such as methanol, ethanol, propanol, butanol, octane, nonane, isocyanate-containing compounds, hydrocarbons with 1 to 20, in particular 5 to 18, carbon atoms, polymers such as polyethers, polyesters, polyamides, polyurethanes. This can be done directly with the in step b. obtained mixture are brought into contact, for example by adding the respective nonionic compound.

Examples of acids are hydrochloric acid, sulfuric acid, nitric acid, carboxylic acids having 1 to 20, in particular 1 to 10, carbon atoms, in particular formic acid, acetic acid, propionic acid and benzoic acid, and mixtures thereof. In particular, the acid be selected from hydrochloric acid and carboxylic acids having 1 to 10 carbon atoms. This can be done directly with the in step b. obtained mixture are brought into contact, for example by adding the respective acid, or by dipping the mixture in acid. The acid can be concentrated or diluted, for example as a dilute aqueous solution.

Examples of bases are hydroxide bases such as sodium hydroxide, potassium hydroxide, calcium hydroxide, amine bases such as primary amines, secondary amines, tertiary amines, in particular triethylamine, pyridine and dimethylaminopyridine and mixtures thereof. This can be done directly with the in step b. obtained mixture are brought into contact, for example by direct addition of the respective base. Alternatively, the respective base can also be used as a solution, in particular as an aqueous solution, with the in step b. obtained mixture are brought into contact, for example by adding a solution, or by immersing the mixture in the solution.

Examples of polar solvents are water and alcohols such as methanol, ethanol, propanol and butanol, primary and secondary amines, carboxylic acids and mixtures thereof. In particular, the polar solvent can be water, an alcohol or a mixture thereof. This can be done directly with the in step b. obtained mixture are brought into contact, for example by adding the polar solvent, or by immersing the mixture in the polar solvent.

Examples of non-polar solvents are hydrocarbons with 5 to 16 carbon atoms, benzene, toluene, pentane, hexane, heptane, cyclohexane, carbon tetrachloride, tetrachloroethene, trichloroethene, carbon disulfide, tetramethylsilane and hexamethyldisiloxane. The non-polar solvent can in particular be hexamethyldisiloxane. This can be done directly with the in step b. obtained mixture are brought into contact, for example by adding the polar solvent, or by dipping the mixture into the non-polar solvent.

Solvent mixtures include, in particular, mixtures of the aforementioned polar and non-polar solvents, in particular mixtures of hexamethyldisiloxane with other solvents such as ethanol, methanol, propanol and butanol. This can be done directly with the in step b. obtained mixture are brought into contact, for example by adding the solvent mixture, or by the mixture is immersed in the solvent mixture. In the case of freeze-drying, the mixture from step b. are first quick-frozen and then dried at temperatures equal to or less than 0 ° C by applying a vacuum.

The temperature can in particular be lowered to below the temperature at which the polymer is poorly or no longer soluble in the polar aprotic solvent. The temperature decrease can include a decrease to temperatures from -5 ° C to 15 ° C, in particular 0 ° C to 10 ° C.

During evaporation, the temperature can be increased so that the polar aprotic solvent evaporates completely and leaves the polymer on the fibers of the material. The evaporation can be carried out at temperatures from 50 ° C to 250 ° C, in particular from 70 ° C to 200 ° C.

The temperature can be increased to temperatures from 50 ° C. to 200 ° C., in particular from 70 ° C. to 150 ° C. The temperature increase can take place gradually or suddenly.

The pressure reduction can take place at pressures from 0.1 mbar to 900 mbar, in particular from 1 mbar to 800 mbar, 10 mbar to 700 mbar or 50 mbar to 500 mbar. The reduction in pressure can in particular be combined with the increase in temperature and the decrease in temperature.

The lowering of the temperature can also, in particular, involve bringing into contact with an ionic compound, bringing into contact with a non-ionic compound, bringing into contact with an acid, bringing into contact with a base, bringing into contact with a polar solvent , bringing into contact with a non-polar solvent and bringing into contact with a solvent mixture.

The treatment of the mixture in step c preferably comprises. bringing into contact with a non-polar solvent, in particular immersion in a non-polar solvent, in particular hexamethyldisiloxane, or consists of it. Optimal results have been achieved when the mixture of the fiber-containing material and the mixture containing at least one polymer and a polar aprotic solvent was brought into contact with hexamethyldisiloxane, in particular immersed in hexamethyldisiloxane.

The aforementioned treatment options allow the polymer to accumulate on the fibers of the material containing fibers. Better results were achieved if the deposition took place as slowly as possible. This can be achieved in particular by treating the mixture of the fiber-containing material and the mixture containing at least one polymer and a polar aprotic solvent for at least 15 seconds, in particular 30 seconds, 1 minute, 5 minutes, 15 minutes, 30 minutes Minutes, 45 minutes, 1 hour, 5 hours, 10 hours, 15 hours or 24 hours and at most for a period of 150 hours, in particular 144 hours, 120 hours, 100 hours, 96 hours, 90 hours or 85 hours. Optimal results have been obtained when the treatment in step c. takes place over a period of 24 to 85 hours, in particular 50 to 80 hours or 65 to 75 hours or 72 hours. This results in a slow accumulation of the polymer on the fibers of the material containing fibers.

The mixture of the fiber-containing material and the mixture containing at least one polymer and a polar aprotic solvent is advantageously treated by bringing it into contact with a non-polar solvent, in particular immersion in a non-polar solvent, in particular hexamethyldisiloxane, over a period of 65 to 75 hours , especially 72 hours.

The method according to the invention can preferably also be used after the treatment in step c. the additional step of drying the in step c. obtained fibrous material comprise.

The drying of the in step c. The fiber-containing material obtained in the process according to the invention is preferably carried out at 20 ° C to 100 ° C, in particular 30 ° C to 90 ° C, 40 ° C to 80 ° C, or 45 ° C to 65 ° C. This is done in step c. fiber-containing material obtained by the process according to the invention is preferably dried for 1 to 25 hours, in particular for 5 to 20 hours, 8 to 16 hours, 9 to 15 hours, 10 to 14 hours or 11 to 13 hours.

The method according to the invention can also be carried out prior to step a. comprise the further step that the material containing fibers, in particular paper, is predried at a temperature of 40 to 80 ° C., in particular 45 to 70 ° C. or 45 to 65 ° C. The predrying can take place for a period of 1 minute to 60 hours, in particular 1 hour to 50 hours or 12 to 48 hours.

The mixture containing at least one polymer and a polar aprotic solvent can be produced in different ways. For example, the mixture can be prepared at room temperature or at a lower or higher temperature, for example at 10 ° C to 150 ° C. The mixture can also be prepared in several steps. If the polar aprotic solvent contains an ionic liquid or the polar aprotic solvent is a mixture of an ionic liquid and at least one of acetonitrile, dimethylformamide, dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, acetone, gammabutyrolactone, N-methyl-2-pyrrolidone, tetramethylurea, dimethylpropylene urea , Sulfolane, dimethyl carbonate and ethylene carbonate, in particular at least one of dimethylacetamide, dimethyl sulfoxide and acetonitrile, the mixture containing at least one polymer and a polar aprotic solvent can be prepared in particular by first dissolving the polymer in the ionic liquid and then dissolving the resulting solution with at least one of acetonitrile, dimethylformamide, dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, acetone, gammabutyrolactone, N-methyl-2-pyrrolidone, tetramethylurea, dimethylpropyleneurea, sulfolane, dimethyl carbonate and ethylene carbonate, especially min at least one of dimethylacetamide, dimethyl sulfoxide and acetonitrile is diluted. Alternatively, the ionic liquid can first be mixed with at least one of acetonitrile, dimethylformamide, dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, acetone, gammabutyrolactone, N-methyl-2-pyrrolidone, tetramethylurea, dimethylpropyleneurea, sulfolane, dimethyl carbonate and ethylene carbonate and then mixed with the, especially dimethyl sulfoxide desired amount of the polymer can be added.

The mixture containing at least one polymer and a polar aprotic solvent can in particular 1 to 30% by weight, in particular 3 to 30% by weight, 5 to 30% by weight, 10 to 30% by weight, 12 to 25% by weight or 15% by weight Up to 20% by weight or 17 to 19% by weight of ionic liquid, based in each case on the total weight of the mixture. Mixtures with the abovementioned contents of ionic liquids can be easily produced; in particular, solutions can be obtained in this way that allow the fiber-containing material to be processed effectively.

The mixing, in particular the swelling, dissolving or dissolving, of the polymer and / or the subsequent dilution can take place at temperatures from 10 ° C. to 150 ° C., in particular from 20 ° C. to 140 ° C., 30 ° C. to 130 ° C., 40 ° C. ° C to 120 ° C, 50 ° C to 110 ° C or 60 ° C to 100 ° C be performed. In this way, a mixture, in particular a solution, with a concentration of the polymer of 5 to 20% by weight, in particular 7 to 15% by weight, 8 to 13% by weight or 9 to 11% by weight, can be obtained in each case based on the total weight of the polymer and the ionic liquid in which the ionic liquid is produced. This solution can then in particular with at least one of acetonitrile, dimethylformamide, dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, acetone, gammabutyrolactone, N-methyl-2-pyrrolidone, tetramethylurea, dimethylpropyleneurea, sulfolane, dimethyl carbonate and ethylene carbonate, in particular at least one of dimetonethylsulfamide, dimetonethyl sulfoxide, and in particular at least one of dimetonethylsulfamide , can be diluted to the desired concentration. In addition, the ionic liquid can also be mixed with at least one of acetonitrile, dimethylformamide, dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, acetone, gammabutyrolactone, N-methyl-2-pyrrolidone, tetramethylurea, dimethylpropyleneurea, sulfolane, dimethyl carbonate, especially dimethyl carbonate, with a concentration of the ionic liquid of 1 to 30% by weight, in particular 3 to 30% by weight or 5 to 30% by weight or 10 to 30% by weight or 12 to 25% by weight or 15 to 20% by weight or 17 to 19% by weight, based in each case on the total weight of the mixture, in particular the ionic liquid and dimethyl sulfoxide, are mixed. The polymer can then be added to this solution in the desired amount. In this way, the mixture containing at least one polymer and a polar aprotic solvent can be produced in a simple manner. Furthermore, the concentration of the polymer in the mixture can be adjusted well in this way.

The mixture containing at least one polymer and a polar aprotic solvent advantageously contains 0.1 to 10% by weight, in particular 0.5 to 8% by weight or 1 to 5% by weight, based in each case on the total weight of the mixture, of polymer. Solutions with these concentrations have in particular a suitable viscosity for the method according to the invention.

A material containing fibers, in particular paper, can be obtained by the process according to the invention.

A system comprising at least two materials containing fibers can be obtained by the method according to the invention, in particular a book.

The materials of the system can be the same or different. The materials containing fibers can have been processed simultaneously or at different times by the method according to the invention. The system can furthermore also comprise materials, in particular materials containing fibers, which have not been processed with the method according to the invention.

The system can in particular be a book, a booklet, a magazine or a newspaper. The material containing fibers can in particular be paper. In addition to paper, a book in particular can contain further material containing fibers, in particular cardboard, cardboard, textiles or wood.

If the system contains materials containing different fibers, these can be processed separately or together using the method according to the invention. In the case of a book, for example, the paper can be processed separately from the rest of the book, in particular separately from the cover. The book can, however, also be edited without first separating any components, especially with its cover. Whether the components are processed separately can be decided in particular on the basis of the way in which the materials containing fibers are held together in the system, in particular in the book. Examples of ways in which the fiber-containing materials in the system can be held together include thread stitching and adhesive binding.

The invention also relates to the use of a mixture containing at least one polymer and a polar aprotic solvent for processing material containing fibers, in particular paper, in the process according to the invention.

The statements made above for the polar aprotic solvent, for the material containing fibers and / or for the polymer apply analogously to the use of the mixture.

The invention also relates to the use of dimethyl sulfoxide as an antioxidant for processing paper in the process according to the invention.

The invention also relates to the use of an ionic liquid containing a quaternary ammonium cation, in particular an ionic liquid containing a dialkylimidazolium cation, in particular 1-butyl-3-methylimidazolium chloride or 1-butyl-3-methylimidazolium acetate, as an antimicrobial agent for processing paper, in the process according to the invention.

Fig. 1

zeigt eine fluoreszenzmikroskopische Aufnahme einer Schicht eines Papiers, das erfindungsgemäß bearbeitet wurde, wobei als Polymer fluoreszenzmarkierte Cellulose verwendet wurde und wobei die Behandlung durch Tauchen des mit dem Gemisch getränkten Papiers in eine Mischung aus Hexamethyldisiloxan enthaltend 1 Vol.% Ethanol erfolgte. Die Cellulosefasern des Substrats heben sich sehr kontrastreich vom dunklen Hintergrund ab.

Fig. 2

zeigt eine fluoreszenzmikroskopische Aufnahme einer Schicht eines Papiers, das erfindungsgemäß bearbeitet wurde, wobei als Polymer fluoreszenzmarkierte Cellulose verwendet wurde und wobei die Behandlung durch Tauchen des mit dem Gemisch getränkten Papiers in Hexamethyldisiloxan erfolgte. Die Cellulosefasern des Substrats heben sich sehr kontrastreich vom dunklen Hintergrund ab.

Fig. 3

zeigt als Referenz eine fluoreszenzmikroskopische Aufnahme einer Schicht eines nicht bearbeiteten Papiers. Die Cellulosefasern des Substrats sind vom Hintergrund zu unterscheiden, heben sich jedoch nicht so kontrastreich vom Hintergrund ab wie die Cellulosefasern in Fig. 1 oder Fig. 2.

Fig. 4

zeigt eine fluoreszenzmikroskopische Aufnahme einer Schicht eines Papiers, das mit einem Gemisch bearbeitet wurde, das kein Polymer enthielt. Die Cellulosefasern des Substrats sind vom Hintergrund zu unterscheiden, heben sich jedoch nicht so kontrastreich vom Hintergrund ab wie die Cellulosefasern in Fig. 1 oder Fig. 2.

The attached figures show:

Fig. 1

shows a fluorescence microscope image of a layer of paper that has been processed according to the invention using fluorescence-marked cellulose as the polymer and the treatment being carried out by dipping the paper soaked with the mixture in a mixture of hexamethyldisiloxane containing 1% by volume of ethanol. The cellulose fibers of the substrate stand out against the dark background with great contrast.

Fig. 2

shows a fluorescence microscope image of a layer of paper which has been processed according to the invention using fluorescence-marked cellulose as the polymer and the treatment being carried out by immersing the paper soaked with the mixture in hexamethyldisiloxane. The cellulose fibers of the substrate stand out against the dark background with great contrast.

Fig. 3

shows, as a reference, a fluorescence microscope image of a layer of unprocessed paper. The cellulose fibers of the substrate can be distinguished from the background, but do not stand out from the background as well as the cellulose fibers in Fig. 1 or Fig. 2 .

Fig. 4

Figure 3 shows a fluorescence micrograph of a layer of paper processed with a mixture containing no polymer. The cellulose fibers of the substrate can be distinguished from the background, but do not stand out from the background as well as the cellulose fibers in Fig. 1 or Fig. 2 .

The invention is described in more detail below on the basis of exemplary embodiments, which, however, only serve for illustration and are not restrictive.

Embodiments Chemicals

1-butyl-3-methylimidazolium chloride (BMIM-Cl), Sigma-Aldrich; 1-butyl-3-methylimidazolium acetate (BMIM-OAc), obtained by anion exchange starting from BMIM-Cl; Viscose (danufil, 3.3 dtex / 0.3 mm, hereinafter: "Danufil"), Kelheim Fibers GmbH; Dimethylacetamide (DMAc), CSC Jäklechemie GmbH & Co. KG; Dimethyl sulfoxide (DMSO), CSC Jäklechemie GmbH & Co. KG; Hexamethyldisiloxane (HMDO), Chemische Fabrik Karl Bucher GmbH; microcrystalline cellulose (MCC), Sigma-Aldrich; Pulp (ENO PINE ECF); Stora Enso Oyj; alpha-cellulose, Sigma-Aldrich.

Measurement methods

Measurements were carried out according to the table below. Table 1: Measurement methods property Measurement method Breaking strength of paper EN ISO 1924-2: 2008 D. Elongation at break of paper EN ISO 1924-2: 2008 D. PH value ISO 6588-1: 2012 viscosity Determination with a "Gemini" rotational viscometer from Bohlin at 25 ° C

All substrates or papers were heated in a preceding step at 55 ° C. for 24 hours unless otherwise stated. Since different papers were used in the different examples, the papers used in different examples may have deviations in the measured values from one another, which is why only the values within one example can be directly compared with one another.

Example 1 (processing of paper with viscose in a mixture of DMAc and BMIM-OAc)

First, a solution containing 10% by weight of Danufil in BMIM-OAc was produced, which was then diluted to a viscose content of 2% by weight, based on the total weight of the solution, by adding DMAc, the solution of BMIM-OAc and DMAc 18% by weight BMIM-OAc and 82% by weight DMAc, each based on the weight of BMIM-OAc and DMAc. The viscosity of the solution was 10 mPa · s. Subsequently the paper to be processed was soaked in the prepared solution for one minute and then rinsed with DMAc for 30 seconds. The paper obtained in this way was then immersed in HMDO (500 g) for 72 hours, as a result of which the viscose attached to the paper fibers. After treatment in HMDO, the paper was heated at 55 ° C for 12 hours. The breaking force, elongation at break and the pH value of the processed paper 1 were then determined and compared with an unprocessed paper as a reference. Table 2: Mechanical properties and pH value sample PH value Breaking force [N] Elongation at break [%] reference 4.57 23 ± 2 0.76 ± 0.20 Paper 1 6.64 28 ± 2 0.85 ± 0.07

Table 2 shows that the breaking force, the elongation at break and the pH value when using mixtures containing viscose and mixtures of BMIM-OAc and DMAc can be significantly increased by the processing according to the invention compared to unprocessed paper. The processed paper was visually and haptically equivalent to unprocessed paper. In particular, no bleeding of the ink or the printing inks was observed.

Example 2 (processing of paper with viscose in a mixture of DMAc and BMIM-Cl)

First, a solution containing 10% by weight of Danufil in BMIM-CI was prepared, which was then diluted by adding DMAc to a viscose content of 2% by weight, based on the total weight of the solution, the solution being made up of BMIM-CI and DMAc 18% by weight BMIM-CI and 82% by weight DMAc, each based on the weight of BMIM-CI and DMAc. The viscosity of the solution was 10 mPa · s. The paper to be processed was then soaked in the prepared solution for one minute and then rinsed with DMAc for 30 seconds. The paper obtained in this way was then immersed in HDMO (500 g) for 72 hours, as a result of which the viscose adhered to the paper fibers. After the treatment in HDMO, the paper was heated at 55 ° C for 12 hours. The breaking force, the elongation at break and the pH value of the processed paper 2 were then determined and compared with a non-processed paper as a reference. Table 3: Mechanical properties and pH value sample PH value Breaking force [N] Elongation at break [%] reference 4.14 29 ± 2 0.66 ± 0.10 Paper 2 4.24 36 ± 3 0.84 ± 0.10

Table 3 shows that the breaking force and elongation at break when using mixtures containing viscose and mixtures of BMIM-CI and DMAc can be significantly increased by the processing according to the invention compared to unprocessed paper. The processed paper was visually and haptically equivalent to unprocessed paper. In particular, no bleeding of the ink or the printing inks was observed. Furthermore, the pH of the processed paper increased.

Example 3 (processing of paper with MCC in 5% LiCI in DMAc)

First, a solution containing 2% by weight of microcrystalline cellulose in DMAc (containing 5% by weight of LiCl, based on the total weight of LiCl and DMAc), based on the total weight of the solution, was prepared. The viscosity of the solution was 13 mPa · s. The paper to be processed was then soaked in the prepared solution for five minutes. The paper obtained in this way was then immersed in HMDO (500 g) for 72 hours, as a result of which the viscose attached to the paper fibers. After treatment in HMDO, the paper was heated at 55 ° C for 12 hours. The breaking strength and elongation at break of the processed paper 3 were then determined and compared with a paper as a reference which was soaked in DMAc (containing 5% by weight LiCl, based on the total weight of LiCl and DMAc) for one minute, then for 72 hours was immersed in HMDO (500 g) and finally heated at 60 ° C for 12 hours. Table 4: Mechanical properties sample Breaking force [N] Elongation at break [%] reference 22 ± 4 0.67 ± 0.2 Paper 3 41 ± 3 0.76 ± 0.3

Table 4 shows that the breaking force and elongation at break when using mixtures containing MCC and DMAc (containing 5% by weight LiCl) are significantly higher due to the processing according to the invention compared to paper that has not come into contact with a polymer such as MCC . The processed paper was visually and haptically equivalent to unprocessed paper. In particular, no bleeding of the ink or the printing inks was observed.

Example 4 (attachment by different treatments (step c.))

Test papers were soaked with a solution according to Example 1, MCC being used instead of viscose. After soaking in the solution, the papers were rinsed with DMAc as in Example 1 and immersed in the solvents listed in Table 5 for the specified duration. Table 5: Treatments sample Solvent (duration of impregnation) Test paper 4 HMDO (72 h) Test paper 5 5 wt.% EtOH / 95 wt.% HMDO (24 h) Test paper 6 EtOH (<1 min)

After being immersed in the solvents listed in Table 5, the test papers 4 to 6 were heated at 55 ° C. for 12 hours. While test paper 4 had a matt appearance, was flexible and was still stable even after being folded several times, test papers 5 and 6 partly showed a gloss. This suggests that in test paper 4 the MCC accumulated on the paper fibers as above, while in test papers 5 and 6 an inhomogeneous, rather superficial accumulation of the MCC took place. The duration of the treatment and the accumulation of the polymer can thus be influenced by the choice of treatment, in particular by the choice of the solvent in which the dipping is carried out.

Example 5 (comparison of different polymers)

Solutions were prepared according to Example 2, the polymers given in Table 6 being used as the polymer. Test papers were first soaked in the solution for five minutes. The test papers obtained in each case were then immersed in HMDO (500 g) for 72 hours, as a result of which the polymers indicated in Table 6 were attached to the paper fibers. After the treatment in HMDO, the test papers were heated at 55 ° C. for 12 hours. The breaking force and elongation at break of the processed papers were then determined. Table 6: Mechanical properties reference MCC MCC + ENO PINE ENO PINE viscose PVA Breaking force [N] 17 ± 2 23 ± 6 22 ± 2 23 ± 5 28 ± 1 26 ± 2 Elongation at break [%] 1.00 ± 0.12 0.72 ± 0.27 0.81 ± 0.15 0.84 ± 0.33 1.11 ± 0.10 0.99 ± 0.12

The reference sample in Table 6 was soaked in a mixture of BMIM-CI and DMAc without the polymer for five minutes and then immersed in HMDO for 72 hours and then heated at 55 ° C. for 12 hours. It is noticeable from Table 6 that the breaking force as a result of the processing according to the invention has increased significantly compared to the reference paper, while the elongation at break has decreased somewhat. The abovementioned polymers are therefore suitable for strengthening paper in the process according to the invention.

Example 6 (can be combined with deacidification process)

Solutions were prepared according to Example 1 in which a paper that had been deacidified by the papersave method and a paper that had not been deacidified were soaked for one minute. After the impregnation, the papers were rinsed for 30 seconds with DMAc and the papers obtained in this way were each immersed in HMDO (500 g) for 72 hours, as a result of which the viscose was attached to the paper fibers. After treatment in HMDO, the papers were heated at 55 ° C for 12 hours. The breaking force and elongation at break of the processed papers ("solidified" or "deacidified / solidified" in Table 7) and a paper deacidified by the papersave method ("deacidified" in Table 7) were then determined. The breaking force and elongation at break of the starting paper were also determined (“reference” in Table 7), which was neither deacidified according to the papersave method nor processed according to the method according to the invention. Table 7: Mechanical properties reference deacidified solidified deacidified / solidified Breaking force [N] 29 ± 3 32 ± 4 28 ± 1 35 ± 4 Elongation at break [%] 0.66 ± 0.11 0.55 ± 0.01 1.11 ± 0.09 0.84 ± 0.11

In direct comparison, deacidification using the papersave process increases the breaking force while the elongation at break decreases. In the method according to the invention no significant change in the breaking force was observed in this test, while the elongation at break increased significantly. In the case of the sample, which was both deacidified and solidified, both the breaking force and the elongation at break increased significantly. Table 6 shows that the process according to the invention can be combined with deacidification processes such as the papersave process. The increase in elongation at break by the method according to the invention is particularly important here, since the brittleness of papers can be reduced in this way.

Example 7 (application of different polymers to deacidified and non-deacidified substrate)

Solutions were prepared according to Example 1, the polymers used in each case in Table 8 (papers not deacidified) and Table 9 (papers deacidified according to the papersave process) and BMIM-CI as the ionic liquid. The test papers were soaked in the respective solution for one minute and then rinsed with DMAc for 30 seconds. The papers obtained in this way were immersed in HMDO for 72 hours, as a result of which the polymers shown in Tables 8 and 9 respectively attached to the paper fibers. After treatment in HMDO, the papers were heated at 55 ° C for 24 hours. The breaking force and elongation at break of the processed papers were then determined. The reference paper was subjected to essentially the same processing as the other papers, with the difference that the solution in the first step did not contain any polymer, but only dimethylacetamide and BMIM-Cl. Table 8: Mechanical properties of the processed, non-deacidified papers reference Chitin Strength PVA Breaking force [N] 17 ± 2 16 ± 1N 25 ± 2 26 ± 2 Elongation at break [%] 1.00 ± 0.12 0.93 ± 0.19 1.24 ± 0.07 0.99 ± 0.12 reference Chitin Strength PVA Breaking force [N] 17 ± 2 26 ± 2N 32 ± 1 35 ± 3 Elongation at break [%] 1.00 ± 0.12 1.12 ± 0.12 0.74 ± 0.07 0.86 ± 1.12

Tables 8 and 9 show that processing according to the method according to the invention enables, in particular, a higher breaking force to be achieved for deacidified and non-deacidified papers. For starch, in the case of paper that has not been deacidified, an increase in elongation at break can also be observed (see Table 8). The same applies to chitin in the case of deacidified paper (see Table 9). In addition to the ability to be combined with the papersave process, Tables 8 and 9 thus show that the mechanical properties of the papers can be improved by the process according to the invention.

Example 8 (processing of wood)

A solution was prepared according to Example 2. This solution was applied to one side of a wooden board with a brush, rinsed with water and dried for 16 hours at 25 ° C. The surface of the wood shows a clear smoothing of the surface in the processed areas. Varnishes can also be easily applied to the processed areas.

Example 9 (fluorescence microscope images)

A solution containing 2% by weight of fluorescence-labeled cellulose in a mixture of DMSO and BMIM-OAc, the DMSO containing 20% by weight of BMIM-OAc, was produced. Fluorescence-marked cellulose is made of, for example W. Helbert et al. Biomacromolecules 2003, 4, 481-471 , known. The fluorescent marker used was a DTAF marker which is excited at 488 nm, the emission being measured at 515 nm. Two test papers were soaked in this solution for one minute and then rinsed off with DMSO for 30 seconds. The first of these papers (test paper 7) was then immersed for 72 hours in HMDO containing 1% by volume of ethanol (500 g in total). The second of these papers (test paper 8) was immersed in HMDO (500 g) for 72 hours. After the treatment in HDMO or in HMDO / ethanol, the papers were heated at 55 ° C. for 12 hours. A blank sample was also created by first soaking a third test paper (test paper 9) in a mixture of DMSO containing 13% by weight BMIM-OAc but without polymer, then immersing it in HMDO (500 g) for 72 hours and then at 55 ° C was heated for 12 hours. A fourth test paper (test paper 10) that was not processed was used as a reference.

From the test papers 7 to 10, several layers were removed one after the other with adhesive film at one point, with eight layers being able to be removed from the non-processed reference and ten layers being able to be removed from the remaining processed test papers. A picture was taken of the layers under a microscope (Nikon FN-C LWD with Nikon 10x / 0.25 objective) at 488 nm with the same exposure time (220 ms with Q-IMAGING RETIGA 200 RV). Representative illustrations of the layers are in the figures FIGS. 1 to 4 shown.

Fig. 1 shows a picture of layer 3 of test paper 7. It can be clearly seen that the fibers of the paper stand out against the background with a very high contrast. Fig. 2 shows a photograph of layer 3 of test paper 8. It can be clearly seen that the fibers of the paper stand out against the background with a very high contrast. Fig. 3 shows a photograph of layer 3 of the reference. The cellulose fibers can be distinguished from the background, but do not stand out from the background as well as in Fig. 1 and Fig. 2 . Fig. 4 shows a photograph of layer 3 of the blank sample. Here, too, the cellulose fibers can be distinguished from the background, but do not stand out from the background in such a high contrast as in Fig. 1 and Fig. 2 .

The figures are consistent with an accumulation of the fluorescence-labeled cellulose from the mixture on the fibers of the paper. The paper fibers were thus coated with fluorescence-marked cellulose, which strengthened the paper fibers and thus the paper.

Example 10 (editing a book)

A solution containing 1% by weight of alpha-cellulose in a mixture of DMSO and BMIM-OAc, the DMSO containing 6.5% by weight of BMIM-OAc, and a solution containing 2% by weight of alpha-cellulose in a mixture were produced from DMSO and BMIM-OAc, the DMSO containing 11.3% by weight of BMIM-OAc.

A 16-page book from 1943 with the title "Tables for Metalworking" was used as the substrate, which had been dried in a desiccator over orange gel for a period of one week, the moisture content of the book being 6.9% by weight. had decreased to 1.2 wt.%. The book was divided into three almost equal parts by two horizontal cuts.

The middle part of the book was then placed in a vessel, fanned out, after which the vessel was filled with the above-described solution containing 1% by weight of alpha-cellulose and closed. The middle part of the book would be soaked in the solution for 1 minute. Then the middle part of the book was fanned out in a second vessel and rinsed with DMSO for 30 seconds. Then the middle part of the book was fanned out and placed in a third vessel, after which the vessel was filled with HMDO and sealed. After 72 hours, the middle part of the book was removed, 6 hours at 55 ° C and dried over orange gel in a desiccator for a week.

The upper part of the book was processed like the middle part of the book with the difference that instead of the solution containing 1% by weight of alpha-cellulose, the solution containing 2% by weight of alpha-cellulose was used. The lower part of the book was not edited and served as a reference.

In analyzing the processed parts of the book, the following components of the parts of the book were examined: the cover sheet, which is the sheet that forms the first and last pages; a center sheet, which in this case is the sheet that forms the 4th page from the front and the 4th page from the back; the inner leaf, which is the arch that forms the two innermost pages. None of the constituent parts of the parts of the edited book were impaired by the editing according to the invention. The color impression was almost unchanged. The mechanical properties of the various components of the edited book as well as the reference (the lower, non-edited part of the book) are listed in Tables 10 (1% by weight alpha-cellulose) and 11 (2% by weight alpha-cellulose). Table 10: Mechanical properties of the components of the middle part of the processed book (1% by weight alpha-cellulose) as well as the unprocessed lower part of the book (reference) Breaking force reference [N] Machined breaking force [N] Elongation at break reference [%] Elongation at break machined [%] cover sheet 3.5 ± 0.64 9.3 ± 2.5 0.16 ± 0.03 0.61 ± 0.23 Middle sheet 3.5 ± 0.64 8.7 ± 2.4 0.16 ± 0.03 0.61 ± 0.28 Inner sheet 3.5 ± 0.64 10 ± 2 0.16 ± 0.03 0.74 ± 0.21 Breaking force reference [N] Machined breaking force [N] Elongation at break reference [%] Elongation at break machined [%] cover sheet 3.5 ± 0.64 9.3 ± 1.1 0.16 ± 0.03 0.52 ± 0.11 Middle sheet 3.5 ± 0.64 8.1 ± 2.2 0.16 ± 0.03 0.49 ± 0.21 Inner sheet 3.5 ± 0.64 9.4 ± 2.1 0.16 ± 0.03 0.63 ± 0.26

Tables 10 and 11 show for all components of the processed parts of the book more than a doubling of both the breaking force and the breaking elongation compared to the non-processed reference. Books can thus be processed as a whole using the method according to the invention.

Example 11 (comparison of DMSO and DMAc)

A solution containing 1% by weight of Danufil in a mixture of DMSO and BMIM-Cl, the DMSO containing 9.9% by weight of BMIM-CI (hereinafter: "DMSO solution"), and a solution containing 1% by weight were obtained. % Danufil in a mixture of DMAc and BMIM-Cl, the DMAc containing 9.9% by weight of BMIM-CI (hereinafter: “DMAc solution”).

Test paper 11 was soaked in the DMSO solution for one minute, then rinsed with DMSO for 30 seconds, immersed in HMDO (500 g) for 72 hours and then heated at 55 ° C. for 12 hours.

Test paper 12 (blind test without Danufil) was soaked for one minute in DMSO containing 9.9% by weight BMIM-CI, then rinsed with DMSO for 30 seconds, immersed in HMDO (500 g) for 72 hours and then at 55 ° C for Heated for 12 hours.

Test paper 13 was soaked in DMSO for 1.5 minutes, then immersed in HMDO (500 g) for 72 hours and then heated at 55 ° C. for 12 hours.

Test paper 14 was soaked in the DMAc solution for one minute, then rinsed with DMAc for 30 seconds, immersed in HMDO (500 g) for 72 hours and then heated at 55 ° C. for 12 hours.

Test paper 15 (blank test without Danufil) was soaked for one minute in DMAc containing 9.9% by weight of BMIM-CI, then rinsed with DMAc for 30 seconds, immersed in HMDO (500 g) for 72 hours and then at 55 ° C. for Heated for 12 hours.

Test paper 16 was soaked in DMAc for 1.5 minutes, then immersed in HMDO (500 g) for 72 hours and then heated at 55 ° C. for 12 hours.

An unprocessed test paper served as a reference.

The mechanical properties of the test papers 11 to 16 and of the reference were determined and are listed in Table 12 below. Table 12: Mechanical properties of test papers 11 to 13 and the reference Substrate Breaking force [N] Elongation at break [%] Test paper 11 8.1 ± 0.9 0.55 ± 0.10 Test paper 12 5.0 ± 1.6 0.65 ± 0.36 Test paper 13 5.9 ± 1.1 0.55 ± 0.19 Test paper 14 7.1 ± 1.2 0.52 ± 0.11 Test paper 15 5.8 ± 1.0 0.60 ± 0.12 Test paper 16 6.1 ± 1.5 0.59 ± 0.20 reference 3.5 ± 0.64 0.16 ± 0.03

Table 12 shows that the test papers 11 and 14 that were brought into contact with a solution containing Danufil had a higher breaking strength than the test papers 12, 13, 15 and 16 and the reference that was not with a solution containing Danufil in Were brought into contact. The elongation at break values of the test papers 11 to 16 differed only slightly. Furthermore, compared to the reference, the test papers 11 to 16 had both a significantly increased breaking force and a significantly increased elongation at break, the increase in breaking force in the test papers 11 and 14, in which the test paper was each brought into contact with a solution containing Danufil, turned out to be the highest. This example also shows that the mechanical properties can be improved by machining with the method according to the invention.

It can also be seen from Table 12 that the breaking strength of test paper 11 is slightly higher than that of test paper 14. DMSO appears accordingly, especially in combination with

BMIM-Cl and Danufil to be somewhat more suitable than DMAc in the method according to the invention, especially in combination with BMIM-Cl and Danufil. In terms of elongation at break, no clear difference could be seen between test papers 11 and 14.

The above exemplary embodiments show that the mechanical properties of substrates such as paper can be improved by the method according to the invention. Furthermore, the pH of paper can be increased. The method according to the invention is therefore suitable, for example, for the preservation of books. Furthermore, other substrates such as wood can also be subjected to the method according to the invention. In this way, among other things, smoothing of surface unevenness can be achieved, especially with massive material application. In addition, various polymers can be used in the process according to the invention. Furthermore, the process according to the invention can be combined with paper deacidification processes such as the papersave process. Finally, the method is also suitable for processing books as a whole.

Claims (19)

1. Process for processing a material containing fibres, said material containing cellulose, microcrystalline cellulose, pulp, hemicellulose, viscose, chitin, chitosan, alginate, starch, lignin, polyvinyl alcohol, proteins or mixtures thereof, comprising the following steps:

   a. Providing a mixture comprising

   (i) at least one polymer selected from the group consisting of cellulose, alpha-cellulose, microcrystalline cellulose, pulp, hemicellulose, viscose, chitin, lignin, chitosan, alginate, starch, silk, natural silk, silk biopolymers, polyvinyl alcohol, polyvinyl acetate, polyurethanes, polyamides, proteins, polymers or copolymers based on acrylic acid and/or its ester and/or amide derivatives, methacrylic acid and/or its ester and/or amide derivatives, vinyl acetate, itaconic acid, maleic acid, fumaric acid, acryloxypropionic acid, methacryloxypropionic acid, styrene sulfonic acid, ethyl methacrylate-2-sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, phosphoethyl methacrylate, cellulose ethers and mixtures thereof, and

   (ii) a polar aprotic solvent,

   b. contacting the material to be processed with the mixture provided in step a. to obtain a mixture of the material and the mixture provided in step a,

   c. treating the mixture obtained in step b. so that at least part of the polymer attaches itself to the fibres of the material,

   characterized in that the treatment of the mixture in step c.
   comprises or consists of bringing the mixture into contact with a non-polar solvent.
2. Process according to claim 1, characterized in that the material is a cellulose-containing material, in particular paper, cardboard, textiles or wood, in particular paper.
3. Process according to any of the preceding claims, characterized in that the polymer is selected from the group consisting of cellulose, alpha-cellulose, microcrystalline cellulose, pulp, viscose and mixtures thereof.
4. Process according to any of the preceding claims, characterized in that the polymer is viscose, in particular substantially non-derivatized viscose.
5. Process according to any of the preceding claims, characterized in that the polar aprotic solvent is selected from the group consisting of acetonitrile, dimethylformamide, dimethylacetamide, tetrahydrofuran, dimethylsulfoxide, acetone, gamma-butyrolactone, N-methyl-2-pyrrolidone, tetramethylurea, dimethylpropyleneurea, sulfolane, dimethyl carbonate, ethylene carbonate, ionic liquids and mixtures thereof.
6. Process according to any of the preceding claims, characterized in that the polar aprotic solvent is selected from the group consisting of dimethylacetamide, dimethylsulfoxide, acetonitrile, ionic liquids and mixtures thereof.
7. Process according to any of the preceding claims, characterized in that polar aprotic solvents comprise an ionic liquid.
8. Process according to any of the preceding claims, characterized in that the polar aprotic solvent is a mixture of an ionic liquid and at least one of dimethylacetamide, dimethylsulfoxide and acetonitrile.
9. Process according to any of claims 5 to 8, characterized in that the ionic liquid comprises or consists of a cation selected from a 1,3-dialkylimidazolium cation, an alkylpyridinium cation, a tetraalkylammonium cation and a phosphonium cation, and an anion selected from fluoride, chloride, bromide, iodide, formate, acetate, propionate, butyrate, hydrogen sulphate, tosylate, trifluoromethanesulphonate, bis(trifluoromethanesulphonyl)imide, hexafluorophosphate, tetrafluoroborate, benzoate, glycolate, thioglycolate, lactate and glycinate.
10. Process according to any of claims 5 to 9, characterized in that the ionic liquid contains or consists of a dialkylimidazolium cation and an anion selected from chloride, bromide and acetate.
11. Process according to any of the preceding claims, characterized in that the contacting with a non-polar solvent comprises or consists of dipping into the non-polar solvent, in particular hexamethyldisiloxane.
12. Process according to any of the preceding claims, characterized in that the process comprises, after the treatment in step c., the additional step of drying the fibrous material obtained in step c.
13. Process according to any of claims 7 to 12, characterized in that the mixture containing (i) at least one polymer and (ii) a polar aprotic solvent is prepared by first dissolving the polymer in the ionic liquid and then diluting the solution thus obtained with at least one of dimethylacetamide, dimethylsulfoxide and acetonitrile, in particular dimethylacetamide.
14. Process according to any of claims 7 to 13, characterized in that the mixture comprising (i) at least one polymer and (ii) a polar aprotic solvent contains 1 to 30 wt.-%, in particular 3 to 30 wt.-% or 5 to 30 wt.-% or 10 to 30 wt.-% or 12 to 25 wt.-% or 15 to 20 wt.-% or 17 to 19 wt.-% of ionic liquid, in each case based on the total weight of the mixture.
15. Process according to any of the preceding claims, characterized in that the mixture comprising (i) at least one polymer and (ii) a polar aprotic solvent contains 0.1 to 10 wt.-%, in particular 0.5 to 8 wt.-% or 1 to 5 wt.-%, in each case based on the total weight of the mixture, of polymer.
16. Use of a mixture containing (i) at least one polymer and (ii) a polar aprotic solvent for processing material containing fibres, in particular paper, in a process according to any of claims 1 to 15.
17. Use according to claim 16, characterized in that the polar aprotic solvent is characterized by at least one feature of claims 5 to 10 and/or the polymer is characterized by at least one feature of claims 3 to 4.
18. Use of dimethyl sulfoxide as antioxidant for processing paper in a process according to any of claims 1 to 15.
19. Use of an ionic liquid containing a quaternary ammonium cation, in particular an ionic liquid containing a dialkylimidazolium cation, in particular 1-butyl-3-methylimidazolium chloride or 1-butyl-3-methylimidazolium acetate, as an antimicrobial agent for processing paper in a process according to any of claims 1 to 15.

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