EP2038478A2

EP2038478A2 - Method for finishing paper and paper products

Info

Publication number: EP2038478A2
Application number: EP07730254A
Authority: EP
Inventors: Simon Champ; Roland Ettl
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2006-06-27
Filing date: 2007-06-20
Publication date: 2009-03-25
Anticipated expiration: 2027-06-20
Also published as: JP5409356B2; US20090272505A1; PL2038478T3; ES2381999T3; ATE553252T1; CN101479428A; WO2008000665A3; EP2038478B1; JP2009541609A; WO2008000665A2; CN101479428B

Abstract

Process for finishing paper and paper products by treating the surface of paper or paper products with at least one finishing agent, at least one finishing agent being applied in the form of a pattern on the top and/or bottom of paper or paper products, and the papers and paper products obtainable by the process.

Description

Method of finishing paper and paper products

description

The invention relates to a process for finishing paper and paper products by treating the surface of paper and paper products with at least one finishing agent and the finished papers and paper products obtainable by the process.

To improve the properties of paper and paper products, for example, the surface of paper or paper products is treated with finishing agents such as hardeners, water repellents, hydrophilicizing agents and / or paper coating slips. The finishing agents are always applied over the entire surface of the top and / or bottom of the paper or paper products.

From the earlier DE application 10 2005 050 658.5 a method for reducing the absorption of water and water vapor and increasing the dimensional stability of paper and paper products is known. This first compresses cellulose fibers or a paper product obtained therefrom by dewatering on a sieve, then brings the compressed paper product with an aqueous solution and / or dispersion of the reactive material in contact, then lifts with further action of the aqueous solution and / or dispersion compression, the paper product dries and heats it to a temperature at which the reactive material reacts with itself and / or with the cellulose fibers to crosslink. As reactive materials, for example, thermally curable binders such as urea

Formaldehyde adducts, one- or two-component systems based on epoxy resins, polyacrylates and polymethacrylates into consideration. Also in this process, the entire top or bottom of the paper is treated with at least one reactive material.

The object of the invention is to improve the properties of paper and paper products, in particular their stiffness, printability, laminatability and biocidal action against microorganisms in such a way that a sufficient effect is already achieved with a smaller amount of finishing agent in comparison with known methods ,

The object is achieved according to the invention by a method for finishing paper and paper products by treating the surface of paper or paper products with at least one finishing agent, if at least one finishing agent in the form of a pattern is applied to the top and / or bottom of paper or paper products. The finishing agent is preferably applied to the top and / or bottom of paper or paper by means of a printing process. Applied products. Such printing processes belong to the state of the art. They are commonly used to print on sized or coated papers or textiles with printing pastes other than paper finishing equipment. The finishing agent can z. B. after the screen printing, ink-jet printing, flexographic printing or offset printing process on the top and / or bottom of paper or paper products to be printed.

Preferably, the finishing agent is printed on the top of paper or paper products by the ink-jet printing process. For example, the paper may be unsized or a bulk sized paper or paper product. Examples of suitable weight-reducing agents are alkyldiketenes, alkenylsuccinic anhydrides or rosin size.

The invention also relates to papers and paper products which are each obtainable by the process according to the invention. These are essentially writing and printing papers, packaging papers, corrugated cardboard, wallpaper, cardboard, filters and laminates, for example, of a composite of cardboard or paper and at least one film of a thermoplastic material, for example polyethylene, polypropylene, polyamide, polyester or polycarbonate ,

The finishing agent according to the invention, for example, in the form of a grid, a rhombus, spiral, circular, sheet-like, strip-shaped or punctiform printed on the top and / or bottom of paper or paper products, the arrangement of the pattern in an orderly or random (stochastic) can. The finishing materials are always applied according to the pattern. In contrast to known application methods of finishing compositions for paper in which the finishing agent is applied to the entire top or underside of paper, in the method according to the invention the finishing agent is applied to the surface of paper that does not coat the entire surface with it is. For example, the proportion of the total surface area printed with a finishing agent is 0.1 to 90, preferably 1 to 70%, and most is in the range of 10 to 50%. The other part of the surface of the paper not treated with a finishing agent remains untreated. After printing, the printed paper or paper product is dried and optionally heated to a temperature at which the finishing agents crosslink, e.g. to temperatures in the range of 35 to 200 ° C.

The effect achieved with the aid of the method according to the invention, for example the rigidity of a paper, depends on a number of factors, in particular on the composition and amount of finishing agent, on the structure of the finishing agent printed on the paper and on the orientation of the paper, ie the stiffness of the paper depends on the orientation of the cellulose fibers from. It is different for a paper sheet in the machine direction than transverse to it. The finishing agent is in the form of a pattern and may, for example, in the form of a grid, a rhombus, a polygon (eg hexagon, octagon), spiral, circular, area, strip or dot printed on the top and / or bottom of paper or paper products become. The individual strips of a grid or rhombus can have different dimensions, for example a thickness of 0.1 to 100 mm, preferably 1 to 10 mm and a length of 0.1 to 100 mm, preferably 1 to 10 mm. The distance between the individual strips of a grid, ie the unprinted areas, may for example have a spacing of 0.1 to 100 mm, preferably 1 to 10 mm. The grid can be square, rectangular or rhombic. If you print the paper strip-shaped, so the strips can extend over the entire length or width of the paper.

The paper can also be punctiform printed with a variety of points or area, which is to be understood by sheet-like that a larger area is provided with a finishing agent, for. B. an area with the dimensions 2 x 2 to 10 cm or 4 x 1 to 10 cm. For example, circular areas printed on a paper may have a diameter of 1 mm to 10 cm.

The method according to the invention can be integrated into the papermaking process. Thus, for example, it is possible to print the still wet paper with a finishing agent and then dry the paper thus treated and optionally heat it to a higher temperature (170 to 200 ° C) to crosslink the printed finishing agent. However, it is also possible to print on the paper during the drying process or afterwards with a finishing agent, to dry the printed material and, if necessary, to crosslink it. The paper products may be similarly printed during or after manufacture with at least one finishing agent.

As papers which are equipped according to the invention, preferably all types of paper, in particular base papers into consideration. By paper products are meant, for example, packaging papers, corrugated board, wallpaper, cardboard and laminates, for example, from a composite of cardboard or paper and at least one film of a thermoplastic material. For example, cellulose fibers of all kinds, both natural and recovered, in particular recycled paper fibers, which are mostly used in admixture with virgin fibers, can be used to make the papers and paper products. Fresh fibers or fresh fibers are to be understood as meaning cellulose fibers which have hitherto not yet been processed into a paper product or which have not yet been dried. Suitable pulps for the production of the pulps are all qualities customary for this purpose, for example wood pulp, bleached and unbleached pulp and pulps from all annual plants. Wood pulp includes, for example, groundwood, thermomechanical pulp (TMP), chemo-thermo-mechanical pulp (CTMP), pressure groundwood, semi-pulp, high yield pulp, and refiner mechanical pulp (RMP). As pulp, for example, sulphate, sulphite and soda pulps come into consideration. It is preferred to use unbleached pulp, also referred to as unbleached kraft pulp. Suitable annual plants for the production of paper materials are, for example, rice, wheat, sugar cane and kenaf.

The paper or paper products according to the invention are printed according to the pattern with a finishing agent. As the finishing agent, there are used, for example, a solidifier, a hydrophobing agent, a hydrophilizing agent, a paper coating slip or an indicator system for biomaterials (e.g., bacteria or viruses). It is particularly preferable for the equipment to use at least one agent which increases the rigidity of paper. These agents mostly also increase the dry and / or wet strength of paper and paper products at the same time. Other finishing agents are conventional dry strength agents and / or wet strength agents for paper.

In order to increase the rigidity of paper and paper products, a thermally curable binder from the group of urea-formaldehyde adducts, urea-glyoxal adducts, melamine-formaldehyde, is preferably used according to the invention.

Adducts, phenol-formaldehyde adducts, one- and two-component systems based on epoxy resins, polyurethanes or isocyanates, polyacrylates, polymethacrylates, styrene- (meth) acrylate copolymer dispersions and / or styrene-butadiene- (meth) acrylic acid copolymer dispersions , In some cases, the use of mixtures of at least two reactive materials of interest e.g. Mixtures of melamine / urea-formaldehyde condensates. The reactive materials may be present as an aqueous solution or as an aqueous dispersion. In this case, transitions between solution and dispersion are possible. If dispersions are used, the average particle diameter of the polymer particles dispersed in water is, for example, below 1 μm, preferably below 500 nm and most in the range from 10 to 100 nm.

The aqueous solution and / or dispersion thus contains, for example, a group of a reactive, crosslinkable material which consists of

(i) at least one reactive substance which forms a polymer,

(ii) optionally at least one Ci-5-alcohol, at least one polyol or mixtures thereof and

(iii) at least one catalyst

can exist. Examples of (i) a reactive substance which forms a polymer are urea-glyoxal adducts and their derivatives, eg, 1,3-bis (hydroxymethyl) -4,5-dihydroxyimidazolidinone-2 (hereinafter called "DMDHEU"). When printing on paper or paper products, it can be used either alone or together with (ii) at least one C 1-5 -alcohol, a polyol or mixtures thereof. If you 1, 3

Bis (hydroxymethyl) -4,5-dihydroxyimidazolidinone-2 is used together with an alcohol and / or a polyol as finishing agent, correspondingly modified 1, 3-bis (hydroxymethyl) -4,5-dihydroxyimidazolidinone-2 (hereinafter "mDMDHEU" called ). Such compounds are known, for example, from US Pat. No. 4,396,391 and WO 98/29393. These are reaction products of 1, 3-bis (hydroxymethyl) -4,5-dihydroxyimidazolidinon-2 with at least one Ci-5-alcohol, at least one polyol or mixtures thereof.

The compounds of group (ii) include C 1-5 -alcohols, for example methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol and n-pentanol, preferably methanol, and also polyols, such as ethylene glycol , Diethylene glycol, 1, 2 and 1, 3-propylene glycol, 1, 2, 1, 3, and 1, 4-butylene glycol, glycerol, trimethylolpropane and polyalkylene glycols such as polyethylene glycol, polypropylene glycol, block copolymers of ethylene glycol and propylene glycol. Preference is given to polyethylene glycols of the formula HO (CH ₂ CH ₂ O) _n H where n is from 3 to 20 and diethylene glycol.

To prepare modified 1,3-bis (hydroxymethyl) -4,5-dihydroxyimidazolidinone-2 (DMDHEU), DMDHEU and the monohydric alcohol and / or the polyol are mixed, the monohydric alcohol and / or the polyol being in an amount of each 0.1 to 2.0 molar equivalents, based on DMDHEU, are used. The mixture of DMDHEU, monohydric alcohol and / or polyol is reacted, for example, at temperatures of 20 to 70 ° C and a pH of 1 to 2.5, wherein the pH after the reaction is adjusted to 4 to 8.

Under (i) a reactive substance which forms a polymer, both urea

Formaldehyde adducts and urea-glyoxal adducts and their derivatives to understand. The following compounds may be mentioned by way of example: dimethylolurea, bis (methoxymethyl) urea, tetramethylolacetylenediurea, methylolmethylurea and 1,3-dimethyl-4,5-dihydroxyimidazolidinone-2, 1, 3-bis (hydroxymethyl) imidazolidinone-2 or mixtures thereof , These compounds of group (i) may also be used in the presence of (ii) at least one C1-5 alcohol, at least one polyol or mixtures thereof as finishing agents. Suitable alcohols and polyols have already been mentioned above. Preference is given to methanol, diethylene glycol or mixtures thereof.

The aqueous solution of the finishing agent contains the reactive compounds of group (i) and the compounds of group (ii), for example, in one concentration from 1 to 70 wt .-%, preferably 10 to 60 wt .-% and in particular 20 to 60 wt .-%. The impregnating agent preferably contains 1, 3-bis (hydroxymethyl) -4,5-dihydroxyimidazolidinone-2 (DMDHEU) as a compound of group (i).

The finishing agent always contains a catalyst (iii) apart from (i) and optionally (ii). Suitable catalysts (iii) are, for example, metal salts from the group of metal halides, metal sulfates, metal nitrates, metal tetrafluoroborates, metal phosphates or mixtures thereof. Specific examples of (iii) are magnesium chloride, magnesium sulfate, zinc chloride, lithium chloride, lithium bromide, boron trifluoride, aluminum chloride, aluminum sulfate, zinc nitrate and sodium tetrafluoroborate. The compounds mentioned can be used either alone or in admixture as a catalyst.

Further suitable catalysts (iii) are ammonium salts such as ammonium chloride, ammonium sulfate, ammonium oxalate, diammonium phosphate or mixtures thereof. In addition, as a catalyst organic and / or inorganic acids can be used. Examples of these are maleic acid, formic acid, acetic acid, propionic acid, citric acid, tartaric acid, oxalic acid, p-toluenesulfonic acid, hydrochloric acid, sulfuric acid, boric acid or mixtures thereof.

The compounds of group (iii) used are preferably magnesium chloride, zinc chloride, magnesium sulfate, aluminum sulfate or mixtures of these compounds. Particularly preferred is magnesium chloride.

The catalyst (iii) is, for example, in a concentration of 0.1 to 10 wt .-%, preferably 0.2 to 8 wt .-%, particularly preferably 0.3 to 5 wt .-%, based on the components (i ) - (iii) of the reactive material.

Of the products described above, which contain condensed formaldehyde, in particular low-formaldehyde condensation products are used. In terms of formaldehyde, it should be understood in the present context that the reactive materials do not contain significant amounts of free formaldehyde and that no substantial amounts of formaldehyde are released during drying or curing of the cellulose fibers or paper products treated therewith. In general, such reactive materials contain <100 ppm formaldehyde.

Other reactive materials which react with themselves and / or cellulose fibers with crosslinking are formaldehyde-free, thermally curable binder into consideration. Such binders are described, for example, in the following references, which are hereby incorporated by reference into the disclosure of the present invention, namely US 4 076 917, EP-A 0 445 578, EP-A 0 583 086, EP-A 0 651 088, WO 97/31036, page 4, line 12 to page 12, line 14, WO 97/31059, page 2, line 22 to page 12, line 5, WO 97/31060, page 3, line 8 to page 12, line 36, DE-A 199 49 591, page 3, line 5 to page 7, line 38, WO 01/27163, page 5, line 34 to page 22, line 2 and the radiation-curable binder known from DE-A 199 17 965.

Thermally curable binders other than the binders described in the above-mentioned references are all curable binders which are described, for example, for solidifying fibrous webs in the literature and / or which are used for this purpose in practice, such as thermosetting resins based on phenol and formaldehyde, the abovementioned melamine-formaldehyde and urea-formaldehyde resins, urea-glyoxal resins and in particular formaldehyde-free one and two-component systems based on epoxy resins or polyurethanes, polyacrylates, polymethacrylates, polyvinyl acetates, styrene acrylate Copolymer dispersions, styrene-methacrylate copolymer dispersions, styrene-butadiene (meth) acrylic acid copolymer dispersions and mixtures of said dispersions with a mixture of a polycarboxylic acid and a polyhydric alcohol as crosslinking component.

Examples of preferred finishing agents are thermally curable binders in the form of blends of

(a) a polymer obtainable by free radical polymerization and containing from 5 to 100% by weight of an ethylenically unsaturated carboxylic anhydride or an ethylenically unsaturated dicarboxylic acid whose carboxylic acid groups may form an anhydride group, and (b) at least one alkanolamine containing contains at least two hydroxyl groups in the molecule and / or at least one polyhydric alcohol.

Specific examples of such mixtures are aqueous solutions containing about 40 to 60% by weight of solids and / or dispersions of a copolymer of 80% by weight of acrylic acid and 20% by weight of maleic acid having a molecular weight M _w of 15,000 to 900,000 μm Combination with triethanolamine or aqueous solutions of a copolymer of 55% by weight of acrylic acid and 45% by weight of maleic acid in combination with triethanolamine. These binders may optionally contain an esterification catalyst and / or a bound phosphorus-containing compound such as hypophosphorous acid as a reaction accelerator. The copolymer (a) described above may, for example, also be composed of

From 50 to 99.5% by weight of at least one ethylenically unsaturated mono- or dicarboxylic acid,

0.5 to 50% by weight of at least one ethylenically unsaturated compound selected from the group consisting of esters of ethylenically unsaturated monocarboxylic acids and the monoesters and the diesters of ethylenically unsaturated dicarboxylic acids having at least one hydroxyl-containing amine; and up to 20% by weight of another monomers.

Thermally curable, aqueous compositions containing at least one copolymer (a) and at least one alkanolamine or higher-functionality .beta.-hydroxyalkylamine and / or at least one polyhydric alcohol may optionally additionally contain at least one surfactant.

Other thermosetting binders useful as finishing agents are based on aqueous mixtures of

Polycarboxylic acids such as polyacrylic acid, polymethacrylic acid, copolymers of acrylic acid and maleic acid, copolymers of ethylene and maleic acid, styrene and maleic acid, or copolymers of acrylic acid or methacrylic acid and esters of acrylic or methacrylic acid with preferably monohydric 1 to 24 C Atoms containing alcohols, wherein the polycarboxylic acids have a K value of 50 to

100 (measured in non-neutralized form of the polycarboxylic acids according to H. Finkentscher in dimethylformamide at 25 ° C. and a polymer concentration of 0.1% by weight) and polyhydric alcohols, such as trimethylolpropane, glycerol, 2-hydroxymethylbutanediol-1, 4 or polyvinyl alcohol and / or polyhydric amines and / or alkanolamines.

Polycarboxylic acids, polyhydric alcohols, alkanolamines and polyhydric amines are preferably used in amounts such that the number of acid function of the total number of alcoholic hydroxyl and amine functions is equivalent, see.

EP-A 0 445 578. Also suitable are crosslinkable materials which consist of an aqueous solution of a polycarboxylic acid (homopolymer or copolymer) preferably having a molecular weight M _w of 10,000 or lower and a polyol such as triethanolamine and in which the ratio of the equivalents of Hydroxyl groups to equivalents of carboxyl groups in the range of 0.4: 1 to 1, 0: 1, cf. EP-A 0 990 727. In the process according to the invention reactive materials are used with particular advantage as finishing agents, which are marketed under the trademark Aerodur® by BASF Aktiengesellschaft. An example of this is an aqueous polystyrene-acrylate polymer dispersion which has been modified with a polycarboxylic acid and a polyhydric alcohol as crosslinking component. It already cross-links at a temperature of 130 ° C. However, in order to achieve high production rates, the crosslinking is preferably carried out at temperatures of 180 to 200 ° C. Another formaldehyde-free binder is commercially available, for example, as a colorless to slightly yellowish, clear, aqueous solution of a modified polycarboxylic acid with a polyhydric alcohol as crosslinking component. It cross-links eg at drying temperatures of approx. 160 to 180 ° C.

Particularly preferred are formaldehyde-free reactive materials containing at least one polycarboxylic acid and at least one polyhydric alcohol and / or alkanolamine or polyhydric amine. Compositions containing these reactive agents may optionally contain other formaldehyde-free polymers, e.g. Polyacrylates sold under the trademark Acronal® by BASF Aktiengesellschaft. The aqueous solutions and / or dispersions of a reactive material used for printing contain the reactive material, for example, in an amount of 1 to 70 wt .-%, preferably 10 to 60 wt .-% and usually 30 to 50 wt .-%.

Further finishing agents are water repellents from the group consisting of alkyldiketenes, alkenylsuccinic anhydrides, rosin size, polymer sizes based on styrene (meth) acrylate polymers and isocyanates. Suitable alkyldiketenes are preferably C ₄ - to C 22 -alkyl- or alkenyl-diketenes. They are prepared for example from the corresponding carboxylic acid chlorides by elimination of hydrogen chloride with tertiary amines. The diketenes which can be used according to the invention can carry saturated or unsaturated, branched or cyclic hydrocarbon radicals. Examples of such alkyldiketenes are tetradecyldiketen, Hexadecyldiketen, Octadecyldiketen, Dodosyldiketen, Palmityldiketen, Oleyldiketen, Stearyldiketen and Behenyl diketen. Stearyldiketen, Palmityldiketen, Oleyldiketen, Behenyldiketen, Isostearyldiketen or mixtures of Alkyldiketenen eg mixtures of Behenyldiketen and Stearyldiketen or mixtures of Stearyldiketen and Palmityldiketen are preferably used.

Alkenylsuccinic anhydrides are described in detail, for example, in US Pat. No. 3,102,064, EP-A 0 609 879 and EP-A-0 593 075. All alkenyl succinic anhydrides which have hitherto been described in the literature as engine sizing agents for paper are also suitable according to the invention as finishing agents, either alone or in combination with alkyl diketenes. Suitable alkenyl succinic anhydrides contain in the alkyl group an alkyl radical having at least 6 C Atoms, preferably a Ci ₄ - to C24 olefin radical. Particularly preferred alkenylsuccinic anhydrides contain from 16 to 22, usually 16 to 18, carbon atoms in the alkenyl group. They may contain linear, additionally unsaturated or branched alkenyl groups. Alkenylsuccinic anhydrides are accessible for example from α-olefins, which are first isomerized. In this case, a mixture of different isomers is obtained, which is then reacted with maleic anhydride in the manner of an ene reaction to succinic anhydrides. Alkenylsuccinic anhydrides are prepared according to EP-A 0 593 075 by reaction of propylene or n-butylene oligomers with maleic anhydride. Examples of this group of reactive sizing agents are decenylsuccinic anhydride, dodecenylsuccinic anhydride, octenylsuccinic anhydride and n-hexadecenylsuccinic anhydride. The individual isomeric succinic anhydrides can have different sizing effect. For example, 2- and 3-hexadecenyl succinic anhydrides are not as effective as engine sizing agents as are the isomeric 4-, 5-, 6-, 7- and 8-hexadecenyl succinic anhydrides.

Another finishing agent in the context of the present invention is rosin glue (rosin) and derivatives derived therefrom, such as, for example, reaction products of rosin size and maleic anhydride. The derivatives may be branched or unsaturated, e.g. Abietic acid. Also suitable as finishing agents are polymer sizing agents based on styrene and (meth) acrylates, which are preferably obtainable by polymerizing the monomers in the presence of degraded starch. Such sizing agents are known, for example, from EP-A 0 276 770, EP-A 0 257 412, EP-A 0 307 812 and WO 02/14393. If according to the invention sizing agents for paper are used as the finishing agent, then glued papers are obtained which are particularly suitable as writing and printing papers.

Further finishing agents are hydrophilizing agents and water repellents such as ethylene copolymer waxes, siloxane-containing polymers and / or bound fluorine-containing polymers such as Clariant Lodyne® and paper coating slips (aqueous mixtures of at least one pigment and at least one binder based on an acid group-containing copolymer of styrene and Butadiene or from styrene and (meth) acrylate) as well as biocides. The biocide-treated papers and paper products are used, for example, in sanitary or sanitary applications, in the food sector, in particular for the packaging of foodstuffs or for industrial applications, e.g. used for filters.

Suitable biocides are, in particular, compounds from the group of polymers comprising vinylamine units, polymers comprising ethyleneimine units, combinations of at least one vinylamine units-containing polymer and at least one organic quaternary ammonium salt and combinations of at least one polymer containing ethyleneimine units and at least one organic quaternary ammonium salt. The polymers of interest and the organic quaternary ammonium salts are known. From DE-A 196 08 555 it is also known to use vinylamine units or polymers containing ethyleneimine units as biocidal active substances, for example as slimicides in the production of paper. The polymers described in DE-A 196 08 555 which contain vinylamine units or ethyleneimine units are applied by the process according to the invention as a biocide to paper or paper products in the form of a pattern, preferably printed. With regard to the details of the polymers which can be considered according to the invention, reference is therefore made to the abovementioned DE-A 196 08 555, page 1, line 43 to page 10, line 8.

Polymers comprising vinylamine units are obtainable by a two-stage process by polymerization of N-vinylcarboxamides and hydrolysis of the resulting poly (N-vinylcarboxamides) with formation of vinylamine units, cf. US 4,421,602, US 5,334,287, EP-A 0 216 387, US 5,981,689, US Pat.

WO 00/63295, US 6,121,409 and US 6,132,558. Examples of N-vinylcarboxylic acid amides are N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinyl-N-ethyl-acetamide and N-vinylpropionamide. The monomers mentioned can be polymerized either alone, in mixture with one another or together with other monomers. Preference is given to N-vinylformamide.

Suitable monoethylenically unsaturated monomers which are copolymerized with the N-vinylcarboxamides are all compounds which can be copolymerized therewith. Examples of these are vinyl esters of saturated carboxylic acids of 1 to 6 carbon atoms, such as vinyl formate, vinyl acetate, N-vinylpyrrolidone, vinyl propionate and vinyl butyrate, and vinyl ethers, such as C 1 to C 6 alkyl vinyl ethers, e.g. Methyl or ethyl vinyl ether. Further suitable comonomers are esters of alcohols having, for example, 1 to 6 carbon atoms, amides and nitriles of ethylenically unsaturated C3 to C6 carboxylic acids, for example methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate and dimethyl maleate, acrylamide and methacrylamide and also acrylonitrile and methacrylonitrile.

Further suitable compounds which can be copolymerized with N-vinylcarboxamides are carboxylic esters of glycols or polyalkylene glycols, in each case only one OH group esterified, for example hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate and acrylic monoesters of polyalkylene glycols of a molecular weight of 500 to 10,000. Further suitable comonomers are esters of ethylenically unsaturated carboxylic acids with amino alcohols such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminopropyl acrylate, dimethylamino-propyl methacrylate, diethylaminopropyl acrylate, dimethylaminobutyl acrylate and diethylaminobutylacrylate , The basic Acrylates can be used in the form of the free bases, the salts with mineral acids such as hydrochloric acid, sulfuric acid or nitric acid, the salts with organic acids such as formic acid, acetic acid, propionic acid or sulfonic acids or in quaternized form. Suitable quaternizing agents are, for example, dimethyl sulfate, diethyl sulfate, methyl chloride, ethyl chloride or benzyl chloride. Further suitable comonomers are amides of ethylenically unsaturated carboxylic acids such as acrylamide, methacrylamide and N-alkyl mono- and di-amides of monoethylenically unsaturated carboxylic acids having alkyl radicals of 1 to 6 carbon atoms, for example N-methyl acrylic amide, N ₁ N-dimethylacrylamide, N-methylmethacrylamide, N-ethylacrylamide, N-propylacrylamide and tert-butylacrylamide, and basic (meth) acrylamides, such as dimethylaminoethylacrylamide, dimethylaminoethylmethacrylamide, diethylaminoethylacrylamide, diethylaminoethylmethacrylamide, dimethylaminopropylacrylamide, diethylaminopropylacrylamide, dimethylaminopropylmethacrylamide and diethylaminopropylmethacrylamide.

Further suitable comonomers are N-vinylpyrrolidone, N-vinylcaprolactam, acrylonitrile, methacrylonitrile, N-vinylimidazole and substituted N-vinylimidazoles, such as e.g. N-vinyl-2-methylimidazole, N-vinyl-4-methylimidazole, N-vinyl-5-methylimidazole, N-vinyl-2-ethylimidazole and N-vinylimidazolines such as N-vinylimidazoline, N-vinyl-2-methylimidazo-Nn and N-vinyl-2-ethylimidazoline. N-vinylimidazoles and N-vinylimidazolines are also used, except in the form of the free bases, in neutralized or quaternized form with mineral acids or organic acids, the quaternization preferably being carried out with dimethyl sulfate, diethyl sulfate, methyl chloride or benzyl chloride. Also suitable are diallyldialkylammonium halides, e.g. Dialyldimethylammoniumchlorid.

The copolymers contain, for example

95 to 5 mol%, preferably 90 to 10 mol% of at least one N-vinylcarboxamide, preferably N-vinylformamide, and - 5 to 95 mol%, preferably 10 to 90 mol% of monoethylenically unsaturated

monomers

in copolymerized form. The comonomers are preferably free of acid groups.

The polymerization of the monomers is usually carried out in the presence of radical-forming polymerization initiators. The homopolymers and copolymers can be obtained by all known processes, for example by solution polymerization in water, alcohols, ethers or dimethylformamide or in mixtures of various solvents, by precipitation polymerization, reverse suspension polymerization (polymerizing an emulsion of a monomer-containing aqueous phase) an oil phase) and polymerizing a water-in-water An emulsion, for example, in which one dissolves or emulsifies an aqueous monomer solution in an aqueous phase and polymerized to form an aqueous dispersion of a water-soluble polymer, as described for example in WO 00/27893. Subsequent to the polymerization, the homopolymers and copolymers which contain copolymerized N-vinylcarboxamide units are partially or completely hydrolyzed as described below.

In order to prepare polymers containing vinylamine units, preference is given to homopolymers of N-vinylformamide or of copolymers obtained by copolymerizing

N-vinylformamide with

Vinyl formate, vinyl acetate, vinyl propionate, acrylonitrile, methyl acrylate, ethyl acrylate and / or methyl methacrylate

and subsequent hydrolysis of the homo- or copolymers to form vinylamine units from the copolymerized N-vinylformamide units, the degree of hydrolysis being e.g. 1 to 100 mol%, preferably 25 to 100 mol%, particularly preferably 50 to 100 mol% and particularly preferably 70 to 100 mol%. The degree of hydrolysis corresponds to the content of the polymers of vinylamine groups in .mu.m%. The hydrolysis of the above-described polymers is carried out by known methods by the action of acids (eg mineral acids such as sulfuric acid, hydrochloric acid or phosphoric acid, carboxylic acids such as formic acid or acetic acid, or sulfonic acids or Phsophonsäuren), bases or enzymes, such as in DE-A 31 28 478 and US 6,132,558. When acids are used as hydrolyzing agents, the vinylamine units of the polymers are present as the ammonium salt, while hydrolysis with bases gives rise to the free amino groups.

In most cases, the degree of hydrolysis of the homo- and copolymers used is 85 to 95 mol%. The degree of hydrolysis of the homopolymers is synonymous with the content of the polymers of vinylamine units. For copolymers containing vinyl esters in copolymerized form, in addition to the hydrolysis of the N-vinylformamide units, hydrolysis of the ester groups to form vinyl alcohol units may occur. This is especially the case when carrying out the hydrolysis of the copolymers in the presence of sodium hydroxide solution. Polymerized acrylonitrile is also chemically altered upon hydrolysis. This produces, for example, amide groups or carboxyl groups. The homopolymers and copolymers containing vinylamine units may optionally contain up to 20 .mu.m% of amidine units, which is formed, for example, by reaction of formic acid with two adjacent amino groups or by intramolecular reaction of an amino group with an adjacent amide group, for example of copolymerized N-vinylformamide. The average molecular weights M _{w of} the polymers containing vinylamine units are, for example, 500 to 10 million, preferably 750 to 5 million and particularly preferably 1 000 to 2 million g / mol (determined by light scattering). This molar mass range corresponds, for example, to K values of 30 to 250, preferably 60 to 100 (determined according to H. Fikentscher in 5% strength aqueous saline solution at 25 ° C., a pH of 7 and a polymer concentration of 0.5% by weight. ). Particular preference is given to using polymers containing vinylamine units as the biocide, which have K values of from 85 to 95.

The polymers containing vinylamine units have for example a charge density (determined at pH 7) of 0 to 18 meq / g, preferably of 5 to 18 meq / g and especially of 10 to 16 meq / g.

The polymers containing vinylamine units are preferably used in salt-free form. Salt-free aqueous solutions of polymers containing vinylamine units can be prepared, for example, from the above-described salt-containing polymer solutions by means of ultrafiltration on suitable membranes at separation limits of, for example, 1,000 to 500,000 daltons, preferably 10,000 to 300,000 daltons.

Derivatives of polymers containing vinylamine units can also be used. It is thus possible, for example, to prepare a large number of suitable derivatives from the vinylamine units by amidation, alkylation, sulfonamide formation, urea formation, thiourea formation, carbamate formation, acylation, carboxymethylation, phosphonylation or Michael addition of the amino groups of the polymer. Of particular interest in this context are uncrosslinked polyvinylguanidines which are obtained by reaction of polymers containing vinylamine units, preferably polyvinylamines, with cyanamide (R ¹ R ² N-CN, where R ¹ , R ² = H, C ¹ to C ₄ alkyl, C ₃ to Cβ-cycloalkyl, phenyl, benzyl, alkyl-substituted phenyl or naphthyl), cf. US 6,087,448, column 3, line 64 to column 5, line 14.

The polymers containing vinylamine units also include hydrolyzed graft polymers of, for example, N-vinylformamide on polyalkylene glycols, polyvinyl acetate, polyvinyl alcohol, polyvinylformamides, polysaccharides such as starch, oligosaccharides or monosaccharides. The graft polymers can be obtained by free-radically polymerizing, for example, N-vinylformamide in aqueous medium in the presence of at least one of the stated graft bases together with copolymerizable other monomers and subsequently hydrolyzing the grafted vinylformamide units in a known manner to give vinylamine units. Preferred polymers containing vinylamine units are hydrolyzed homopolymers of N-vinylformamide having a degree of hydrolysis of from 1 to 100 mol%, preferably from 25 to 100 mol%, and from 1 to 100 mol%, preferably from 25 to 100 mol% hydrolyzed copolymers of N-vinylformamide and vinyl formate, vinyl acetate, vinyl propionate, acrylonitrile, methyl acrylate, ethyl acrylate and / or methyl methacrylate having K values of from 30 to 150, in particular from 60 to 100. Particular preference is given in the process according to the invention to the abovementioned partial or fully hydrolyzed homopolymers of N-vinylformamide used.

Typical representatives of these homopolymers of N-vinylformamide are among the

Trade names Catiofast® VFH, Catiofast® VSH and Catiofast® VMP from BASF Aktiengesellschaft.

Preferably, the polyvinylamine contains 0.1 to 22 milliequivalents (meq), more preferably 5 to 18 meq cationic groups per gram of polyvinylamine. The polymers containing vinylamine units are used, for example, in the form of an aqueous dispersion or solution.

The polymers containing ethyleneimine units are preferably polyethylenimines obtainable by polymerizing ethyleneimine in the presence of acids, Lewis acids or acids releasing compounds as catalyst. Such catalysts are, for example, alkyl halides such as methyl chloride, ethyl chloride, propyl chloride, methylene chloride, trichloromethane, carbon tetrachloride or tetrabromomethane. The polyethyleneimines have, for example, molar masses M _w in the range from 120 to 10 million, preferably 500 to 500,000 and in particular from 1000 to 50,000. In addition, compounds containing ethyleneimine units are polymers obtained by grafting polyamidoamines with ethyleneimine or by grafting Polymers of open-chain N-vinylcarboxamides with ethyleneimine are available. Grafted polyamidoamides are known, for example, from US Pat. No. 4,144,123. The polymers containing ethyleneimine units have for example a charge density (measured at pH 7) of 0.1 to 22 meq (milliequivalent), preferably 4 to 10 meq. They are preferably used in aqueous solution.

The polymers containing vinylamine or ethyleneimine units described above are used either alone or in combination with an organic quaternary ammonium salt as a biocide. Such ammonium salts preferably contain at least one, preferably one to four, more preferably one to three, most preferably two to three and in particular three bonded to the N-atom hydrophobic molecule groups such as in particular C 1 to C 30 alkyl groups. Particularly effective biocides are ammonium salts, which preferably have at least one reactive group which causes or favors attachment of the ammonium salt to the substrate surface. The reactive group may be an organic moiety containing at least one functional group capable of reacting with the substrate surface, such as, in particular, epoxy groups, hydroxyl groups, acid groups and alkoxy groups. The ammonium salt preferably contains as reactive group an alkoxylated silane which is bonded to the N atom via a spacer. Such ammonium salts are known, for example, from WO 2004/087226, in particular in claim 6.

The quaternary ammonium salt is preferably a low molecular weight compound and in particular has a molecular weight of less than 2000 g / mol, particularly preferably less than 1500 g / mol, in particular between 200 and 1000 g / mol. It is used in particular in the form of an aqueous dispersion or preferably an aqueous solution. Like the polymers containing amino groups, the organic, quaternary polymer alone as a biocide can be applied to the surface of paper or paper products according to the sample. Preferably, however, it is used in combination with at least one polymer containing vinylamine units and / or at least one polymer containing ethyleneimine units. It is simplest, starting from commercially available aqueous solutions or dispersions of the polymers containing amino groups, mixing them with an aqueous solution of the quaternary amine and then printing the mixture thus obtainable on a paper. However, it is also possible to print a paper or a paper product separately with a polymer containing vinylamine units and / or a polymer containing ethyleneimine units according to pattern and then - optionally after a drying step - at least one organic, quaternary amine also in the form of a pattern imprinted and the printed Then dry the material. As a result, a mixture of the two biocides is also present in this case on the substrate surface.

Regardless of the form of use, the proportion of the polyvinylamine and / or polyethyleneimine is from 1 to 99% by weight, preferably from 10 to 90% by weight and more preferably from 30 to 70% by weight, based on the total by weight of polymer and ammonium salt (solid, no solvent). Accordingly, the proportion of the ammonium salt is likewise 1 to 99% by weight, preferably 10 to 90% by weight and particularly preferably 30 to 70% by weight.

Preferably, a mixture of polyvinylamine and ammonium salt is used, in particular, it is an aqueous solution containing both components. It preferably contains 0.01 to 5 wt. Biocide (sum of polymer and ammonium salt). The non-full-surface treatment of the paper or the paper product with the solution or dispersion, ie preferably according to the pattern printing the Biocides on the substrate can be done at room temperature or immediately after sheet formation in the papermaking process before, during or after drying. After drying, the paper or paper product is equipped accordingly.

The amount of biocide (sum of polymer and ammonium salt) is preferably from 0.001 to 1000 mg, more preferably from 0.1 to 10 mg per square meter surface area of the substrate to be equipped with the biocide.

The biocide-treated substrates may be e.g. for products for medical applications, applications in the sanitary or hygiene sector, in the food sector, in particular in food packaging or to substrates for a variety of industrial applications, in particular filters, e.g. for air conditioning, act.

Compared with the known impregnation processes, the process according to the invention has the advantage that significantly lower amounts of finishing agent are required with approximately comparable properties of the papers and paper products, and thus less expensive manufacture of papers and paper products.

Unless otherwise indicated in the context, the percentages in examples represent percent by weight.

Examples

Determination of rigidity

An A4 sheet was printed according to the invention with a finishing agent, dried and air-conditioned for 24 hours at 25 ° C and 60% humidity. The measurements were carried out at room temperature under the prevailing air pressure. From the center of the DIN A4 sheet printed with a finishing agent according to the invention, a test piece having the dimensions 100 × 100 mm was cut. The test piece was then fixed between two blocks of wood so that 50% of the test piece protruded. The part of the test piece protruding from the blocks was then loaded with weights of 1 to 50 g by placing the weights in the middle of the test piece at a distance of 10 mm from the outer edge. As soon as the end of the test piece protruding from the block reached 25 mm or the weight fell off the paper, the required load in g was measured as a measure of the stiffness. The following equipment was used:

Finishing Agent 1: Mixture of a polycarboxylic acid and a polyvalent one

Amine in the form of a 35% aqueous solution (Aerodur® 950L)

Finishing Agent 2: Mixture of a polycarboxylic acid and a polyvalent one

Amine in the form of a 35% aqueous dispersion (Aerodur® D3515)

Finishing Agent 3: 70% aqueous solution of a thermosetting urea-formaldehyde resin (Fixapret® ECO)

Examples 1 to 36 and Comparative Examples 1 to 16

A4 size sheets were each printed with the amounts of finishing agents shown in the following table using the ink jet printing method with the patterns also shown in the table. The sheets printed with finishing agents 1 to 3 were each stored at 140 ° C for 15 minutes to crosslink the polymers. Thereafter, the stiffness of the paper was determined by the method described above. The results are given in the table.

In the table, "line (MD)" means lines printed on the A4 sheet, which are in the machine direction of the sheet in papermaking, and "line (CD)" lines which are transverse to the machine direction.

In Comparative Examples 1 to 6, water in the print patterns shown in the table was printed on the sheet and the thus-treated sheet was dried each before the determination of rigidity.

table

Claims

claims

1. A method for finishing paper and paper products by treating the surface of paper or paper products with at least one equipment, characterized in that on the top and / or

Underside of paper or paper products at least one finishing agent in the form of a pattern.

2. The method according to claim 1, characterized in that applying the equipment means by means of a printing process on the top and / or bottom of paper or paper products.

3. The method according to claim 1 or 2, characterized in that the finishing agent by the screen printing, ink-jet printing, flexographic or offset-set printing method on the top and / or bottom of paper or

Paper products prints.

4. The method according to any one of claims 1 to 3, characterized in that printing the finishing agent by the ink-jet printing process on the upper side of paper or paper products.

5. The method according to any one of claims 1 to 4, characterized in that one uses a mass-sized paper or paper product.

6. The method according to any one of claims 1 to 5, characterized in that printing the finishing means in the form of a grid, a rhombus, spiral, circular, sheet-like, strip-shaped or punctiform on the top and / or bottom of paper or paper products, wherein the Printed patterns in each case ordered or in random form.

7. The method according to any one of claims 1 to 6, characterized in that one uses as a finishing agent, a solidifier, a hydrophobing agent, a hydrophilizing agent, a paper coating slip and / or a biocide.

8. The method according to any one of claims 1 to 7, characterized in that one uses as a finishing agent at least one agent that increases the stiffness of paper.

9. The method according to any one of claims 1 to 8, characterized in that the finishing agent used as a dry strength agent and / or a wet strength agent for

Paper inserts.

10. The method according to any one of claims 1 to 7, characterized in that as a finishing agent a water repellents from the group alkyldiketenes, alkenylsuccinic anhydrides, resin size, polymer sizing agent based on styrene (meth) acrylate polymers, isocyanates, ethylene copolymer waxes, Siloxane-containing polymers and / or bound fluorine-containing polymers used.

1 1. A method according to any one of claims 1 to 9, characterized in that as finishing agent at least one thermally curable binder from the group of urea-formaldehyde adducts, urea-glyoxal adducts,

Melamine-formaldehyde adducts, phenol-formaldehyde adducts, one- and two-component systems based on epoxy resins, polyurethanes or isocyanates, polyacrylates, polymethacrylates, styrene- (meth) acrylate copolymer dispersions and / or styrene-butadiene- (meth) acrylic acid Copolymer dispersions used.

12. The method according to any one of claims 1 to 9, characterized in that as a finishing agent at least one thermally curable binder from a mixture of

(A) a polymer which is obtainable by free-radical polymerization and which contains from 5 to 100 wt .-% of an ethylenically unsaturated carboxylic acid anhydride or an ethylenically unsaturated dicarboxylic acid whose carboxylic acid groups can form an anhydride group, copolymerized and contains

(b) at least one alkanolamine which contains at least two hydroxyl groups in the molecule and / or at least one polyhydric alcohol,

starts.

13. The method according to any one of claims 1 to 9, characterized in that the finishing agent used is at least one thermally curable binder from an aqueous mixture of at least one polycarboxylic acid and at least one polyhydric alcohol and / or at least one polyhydric amine and / or an alkanolamine.

14. The method according to any one of claims 1 to 7, characterized in that as a finishing agent a biocide from the group of vinylamine containing polymers, ethyleneimine units containing polymers, combinations of at least one vinylamine units containing polymer and at least one organic quaternary ammonium salt and Kombina- tion of at least one ethyleneimine units containing polymer and at least one organic quaternary ammonium salt.

15. Paper and paper products, each obtainable by the process of claims 1 to 14.