EP3755540B1 - Method and devices for producing a product having elements adhered together - Google Patents

Description

The present invention relates to methods and devices for producing a product having at least two elements glued to one another, in particular a cellulose product, and products produced therewith.

Processes for adhesive binding of products, in particular cellulose products, have been known for a long time. Such adhesive binding methods are binding methods for books or other printed products, for example, wherein adhesives are applied to the spine of cut book blocks, which ensure the cohesion of the sheets.

Processes for gluing elements can be divided into cold and hot glue depending on the working temperatures used.

Thermoplastic adhesives which are solid at room temperature and liquid when heated, in particular ethylene-vinyl acetate copolymers or polyurethane hot-melt adhesives, are used in hot-melting. Disadvantages of hot gluing are high energy consumption, high viscosity of the hot-melt adhesive and possible damage to temperature-sensitive elements to be bonded. In addition, the bond obtained does not have sufficient flexibility. In particular when binding books, journals or magazines, this leads to an inflexible opening behavior; in particular, opening at an angle of 180° is not possible and opened books, journals or magazines close again by themselves. For the industrial gluing of paper edges, for example book spines, hot melts have hitherto been predominantly used in view of the need to carry out such industrial gluing processes with a high throughput.

In the field of cold gluing, which is much more gentle, the adhesive (usually polymer dispersions with natural or artificial polymers or synthetic or natural resin dispersions in water, for example aqueous formulations based on acrylate) must be liquid at room temperature and the Paper structure, especially depending on the Viscosity, can wet well. With conventional cold glues, however, the adhesion or durability of the bonded fiber-containing elements with the glue is often too low. As a result, mechanical loads, such as repeated leafing through a book, periodical or magazine, cause individual leaves to loosen from the bond after a short time. It is therefore practically impossible to implement this procedure without so-called molecular primers, which change the adhesive interface in such a way that more intensive wetting is possible and stable glueing occurs. Especially without wetting the cellulose, a durable bond is not possible with aqueous systems. For example, hydrophobic proteins are used as molecular aids ( EP 2 358 837 B1 ). So far, however, these have not simply been available on an industrial scale and, moreover, their processing is not without health concerns. In addition, they have to be laboriously formulated with certain additives and therefore do not offer the ideal conditions for rapid further development of such adhesive systems.

WO2010057946 discloses compositions containing at least one hydrophobin (H) and an adhesive (K) and a corresponding method for gluing paper products, in particular for adhesive binding printed products.

WO2010142507 discloses adhesive compositions and their use, particularly in the medical and surgical field. In particular refers WO2010142507 to an adhesive, detachable and repositionable composition containing a chitin-containing material and/or a chitosan-containing material and to various uses thereof.

Functionalization and pretreatment for the bonding of surfaces that is easy to carry out, inexpensive, sustainable and harmless to health still represents a major challenge for research and development, especially in bonding processes. Pretreatments of surfaces that lead to a changed interface are particularly interesting lead, so that a bond, in particular a stable bond, is made possible.

The present invention is based on the technical problem of overcoming the above disadvantages, in particular of providing methods which lead to a particularly stable bonding of elements to be bonded, in particular when adhesive formulations or cold glues are to be used for bonding.

The present invention is also based on the technical problem of providing bonded products which are characterized by particularly stable bonding of the elements that make them up.

The present invention is also based on the technical problem of providing devices that are suitable, in particular set up, for carrying out the method according to the invention.

The present invention solves the technical problems underlying it by providing the subject matter of the independent claims.

1. a) Bereitstellen mindestens eines ersten mindestens eine Faser-haltige Oberfläche aufweisenden Elements, mindestens eines zweiten Elements, mindestens einer Chitosan-haltigen Lösung und mindestens einer flüssigen Klebstoffformulierung,
2. b) Aufbringen der mindestens einen Chitosan-haltigen Lösung auf mindestens eine zu verklebende Fläche auf der mindestens einen Faser-haltigen Oberfläche des ersten Elements zum Erhalt einer vorbehandelten, die Chitosan-haltige Lösung aufweisenden Klebezone auf dem ersten Element,
3. c) Aufbringen der mindestens einen flüssigen Klebstoffformulierung auf die gemäß Verfahrensschritt b) erhaltene, die vorbehandelte Chitosan-haltige Lösung aufweisende Klebezone und
4. d) Inkontaktbringen des mindestens einen zweiten Elementes mit der Klebezone des ersten Elementes zum Erhalt des verklebten Erzeugnisses.

In particular, the present invention solves the problem on which it is based by providing a method for producing a product having at least two elements bonded together, comprising that

1. a) providing at least one first element having at least one fiber-containing surface, at least one second element, at least one chitosan-containing solution and at least one liquid adhesive formulation,
2. b) applying the at least one chitosan-containing solution to at least one surface to be bonded on the at least one fiber-containing surface of the first element to obtain a pretreated adhesive zone containing the chitosan-containing solution on the first element,
3. c) applying the at least one liquid adhesive formulation to the adhesive zone obtained according to process step b) and having the pretreated chitosan-containing solution and
4. d) bringing the at least one second element into contact with the bonding zone of the first element to obtain the bonded product.

The invention accordingly provides that in a first method step a) at least two elements to be bonded are provided, of which a first element is characterized in that at least one surface of the element is a fiber-containing surface, i.e. has fibers, in particular one made of Has fibers formed surface. Preferably, the first element can have, for example, a coating of fibrous material, for example fibers, for example a fibrous coating. The first element can preferably be made up of the fibers, in particular consist of them. According to the invention it can be provided that the entire surface of the first element is a fiber-containing surface. According to the invention, it can also be provided that only one surface, in particular part of one or more surfaces of the first element, is a fiber-containing surface. In a preferred embodiment, the fiber-containing surface can consist solely of fibers. In a further embodiment, the fiber-containing surface in addition to the fibers, other components such as synthetic and natural polymers, sizes, fillers, dyes, defoamers, dispersing agents, rheological agents, wetting agents or the like. In a preferred embodiment, the fibers present in the fiber-containing surface of the first element provided in process step a), preferably all fibers, can be present over their entire length, but at least over a significant fiber length, in the form of a fiber composite, i.e. in a form in which at least parts of the fibers are in direct physical contact with one another and/or with other components of the element, preferably in close physical contact, for example in pressed form.

In addition, in a first method step a), at least one second element, which is to be glued to the first element, at least one chitosan-containing solution and at least one liquid adhesive formulation are provided.

The invention further provides that in a second method step b) the at least one chitosan-containing solution is applied to a surface to be bonded, in particular to a region of the at least one fibrous surface or to the entire fibrous surface of the first element whereby an adhesive zone comprising the chitosan-containing solution is obtained on the first element, for example the entire fibre-containing surface or a portion of this surface.

In connection with the present invention, the term "adhesive zone" means the area of the fiber-containing surface of the first element to which the chitosan-containing solution was applied and to which in a subsequent process step, in particular without carrying out further steps, in particular intermediate steps , the liquid adhesive formulation is applied.

The pretreated adhesive zone of the first element obtained in method step b) and containing the chitosan-containing solution therefore still has the chitosan-containing solution in the liquid form provided in method step a).

In a third process step c), the at least one liquid adhesive formulation is then applied to the adhesive zone obtained in process step b) and containing the pretreated chitosan-containing solution, for example with a nozzle or roller application, in such a way that a "wet-on-wet" affixed. The invention sees Therefore, in particular, after method step b) and before method step c), there is no drying of the applied chitosan-containing solution, but rather it is brought into contact with the liquid adhesive formulation in its liquid state. In a particularly preferred embodiment, after method step b) and before method step c), no further method step takes place; in particular, it is preferably provided that method step c) takes place directly after method step b).

In a fourth process step d), the second element is then brought into contact with the bonding zone of the first element to obtain the bonded product, optionally with the application of pressure. In a particularly preferred embodiment, no further method step takes place after method step c) and before method step d); in particular, a preferred embodiment provides that method step d) takes place immediately after method step c).

The procedure according to the invention leads to a particularly stable bonding of the elements, which leads to a cohesive failure and not to an adhesive failure, in particular in the case of a tensile test. Unlike chitosan-based priming, in which a chitosan-containing solution is applied to surfaces, dried and then used as an adhesion promoter, the chitosan-containing solution used according to the invention acts as an agent that, in its liquid form, i.e. in the wet state, enables the adhesive formulation to be drawn off and, without being bound by theory, enables improved drawing of the adhesive into the adhesive zone, in particular into the depth of the fiber-containing surface, and thus in particular an enlarged adhesive zone is provided. The chitosan-containing solution gets into even the smallest structures in and on the surface and pulls the adhesive formulation in there, thus providing a surface-enlarged adhesive zone compared to non-pretreatment with a chitosan-containing solution. Without being bound to theory, the chitosan and/or chitosan derivative molecules present in the chitosan-containing solution cause a change in the interface on the fibers in the fiber-containing surface by changing the surface energy. The use according to the invention of the chitosan-containing solution thus allows in particular improved application of an adhesive formulation into the adhesive zone under "wet-on-wet" conditions.

In connection with the present invention, in a preferred embodiment, “wet-on-wet” conditions mean in particular that the chitosan-containing solution penetrates completely into the at least one fiber-containing surface of the at least one first element moves in, i.e. there is no longer any chitosan-containing solution on the at least one fiber-containing surface, but it is completely in the at least one fiber-containing surface, and the chitosan-containing solution still remains in the liquid state, that is, before the application of the at least one liquid adhesive formulation is still liquid.

Accordingly, the at least one chitosan-containing solution is preferably not mixed with the at least one liquid adhesive formulation before the adhesive formulation is absorbed into the adhesive zone, in particular deep into the fiber-containing surface.

In a preferred embodiment of the present invention, it is therefore provided in method step b) that the chitosan-containing solution, after being applied to the at least one surface to be bonded, is largely or, preferably, completely absorbed into the at least one fiber-containing surface of the first element. Accordingly, there is preferably hardly any chitosan-containing solution or, preferably, no more chitosan-containing solution on the at least one fiber-containing surface. Rather, this is largely or, preferably, completely present in the at least one fiber-containing surface, specifically in the liquid state. In a preferred embodiment, the area to be bonded on the fiber-containing surface has undergone a surface enlargement, in particular an exposure of fibers, before this preferred method step b) is carried out.

The application of the at least one chitosan-containing solution in method step b) and the subsequent application of the at least one liquid adhesive formulation in method step c) advantageously also enables a more flexible further development of the bonding technology, since in particular no stable adhesive formulations comprising at least one chitosan or chitosan Derivative would have to be newly developed as an ingredient, but already known adhesive formulations could be used and developed further separately, without taking into account the chemical requirements and influences of at least one chitosan or chitosan derivative.

The present teaching advantageously uses the polyamino sugar chitosan, which is available in sufficient quantity as a renewable raw material and can be obtained in large quantities. Chitosan is stable in solution, especially acidic solution, and allows a sufficient processing time. Compared to proteins, which first have to be obtained through biotechnological processes and digestion methods, chitosan is light as a refined waste material available, its structure as a linear, unbranched polymer resembles the sugar chains of cellulose, is soluble at a slightly acidic pH and is therefore easy to process in so-called "wet-on-wet" processes.

In a particularly preferred embodiment of the present invention, the fibers comprise at least one polymeric compound, also referred to below as “polymer”, in particular the fibers consist of at least one polymer.

The polymer can in particular be a naturally occurring polymer, preferably a biopolymer, for example a natural fiber, in particular a naturally occurring polymer in plants, in particular cellulose. In a particularly preferred embodiment, the fibers are vegetable fibers which preferably contain or consist of cellulose as the polymer.

In a particularly preferred embodiment, the vegetable fibers can be present in the form of paper, cardboard, in particular solid cardboard and corrugated cardboard, cardboard, mechanical pulp, cellulose, semi-chemical pulp or pasteboard, in particular in the form of paper.

In a particularly preferred embodiment of the present invention, the fibers comprise an artificially produced polymer, in particular the fibers consist of an artificially produced polymer, which is in particular a chemically synthesized polymer, in particular a chemically modified polymer based on naturally occurring polymers.

In a particularly preferred embodiment of the present invention, the first element provided in method step a) and having at least one fiber-containing surface is a cellulosic element, in particular a cellulosic product.

In a particularly preferred embodiment of the present invention, the first, the second, further or all of the elements provided in process step a) are cellulose-containing elements, in particular cellulose products.

In a particularly preferred embodiment of the present invention, the first element having at least one fiber-containing surface is selected from the group consisting of paper, cardboard, wood, natural fibers and vegetable fiber materials, with the fibers containing or consisting of cellulose in a particularly preferred embodiment consist. Paper, cardboard, wood, natural fibers or vegetable fiber material can preferably be present in the form of wooden components, wound dressings, textiles, hygiene articles or absorber/adsorber materials, with the fibers containing or consisting of cellulose in a particularly preferred embodiment.

In connection with the present invention, the term paper is understood to mean, in particular, graphic papers, packaging papers, sanitary papers and specialty papers. Graphic papers are preferably all papers for printing, writing and copying, e.g. photographic prints and digital prints. Packaging papers are preferably to be understood as meaning papers, cardboard and paperboard for packaging purposes. Hygienic papers are preferably papers with a high volume and high absorbency, which are typically used in sanitary or kitchen areas. The term special paper preferably refers to paper and cardboard for special technical purposes.

The invention preferably relates to graphic papers. The invention particularly preferably relates to graphic papers which have already been subjected to a printing process, in particular to photographic prints and digital prints. However, unprinted papers can also be used within the scope of the invention.

In a particularly preferred embodiment of the present invention, the first element having at least one fiber-containing surface is selected from the group consisting of paper, cardboard, wood, vegetable fiber materials, natural fibers and/or combinations thereof.

In a particularly preferred embodiment of the present invention, the first element having at least one fiber-containing surface is selected from the group consisting of paper, cardboard, wood, vegetable fiber materials, natural fibers and combinations thereof in combination with synthetic polymers.

In a particularly preferred embodiment of the present invention, the first element having at least one fiber-containing surface is paper, in particular made from fibers of hardwood or softwood, with the fibers containing or consisting of cellulose in a particularly preferred embodiment.

In a particularly preferred embodiment of the present invention, the first element having at least one fiber-containing surface is cardboard, with the fibers containing or consisting of cellulose in a particularly preferred embodiment.

In a particularly preferred embodiment of the present invention, the first element having at least one fiber-containing surface is wood, in particular softwood or deciduous wood, with the fibers containing or consisting of cellulose in a particularly preferred embodiment.

In a particularly preferred embodiment of the present invention, the first element having at least one fiber-containing surface is an element made of vegetable fiber materials, in particular fibers from coniferous or deciduous trees, with the fibers containing or consisting of cellulose in a particularly preferred embodiment.

In a particularly preferred embodiment of the present invention, the second element is selected from a group consisting of plastic element, paper, cardboard, wood, vegetable fibers, natural fibers or combinations thereof, with these being used in a preferred embodiment as wooden components, functional materials, wound dressings, textiles, hygiene articles or Absorber / adsorber materials may be present.

In a particularly preferred embodiment of the present invention, the elements consist of different materials.

In a particularly preferred embodiment of the present invention, the elements consist of the same materials.

In a particularly preferred embodiment of the present invention, the chitosan in the chitosan-containing solution is chitosan or a chitosan derivative. As chitosan derivatives, for example, chitosan esters, chitosanamides, chitosan monomers and other chitosan derivatives such as chitosan conjugates with polyphenols such as 3,4,5-trihydroxybenzoic acid or octyl gallate, salts of organic acids, for example citric acid or polyepoxysuccinate, chitosan-PEG-tyramine, Chitosan amylose, chitosan ester and amine derivatives, carboxy-functionalized chitosans, phosphorylated chitosans, glycosylated, etherified, crosslinked and copolymerized chitosan can be used.

In a particularly preferred embodiment of the present invention, a chitosan derivative according to the invention in the chitosan-containing solution is a chitosan derivative which can be used in a method according to the invention, in particular can be used in a method according to the invention if its use according to the invention leads to that the adhesive formulation used in process step c) moves into the at least one fiber-containing adhesive zone in a shorter time compared to a direct application, i.e. without prior application of the chitosan-containing solution in a process step b), to the at least one fiber durable surface.

In a particularly preferred embodiment of the present invention, at least one chitosan-containing solution is provided in method step a), the chitosan-containing solution containing at least one chitosan or chitosan derivative, in particular one to three chitosans or chitosan derivatives, in particular one to two chitosans or chitosan derivatives, in particular a chitosan or chitosan derivative.

In connection with the present invention, a chitosan-containing solution means in particular a solution which contains at least one chitosan or chitosan derivative, in particular mixtures of chitosans and/or chitosan derivatives.

In connection with the present invention, chitosan is understood as meaning deacetylated chitin. The degree of deacetylation can vary. In a preferred embodiment of the present invention, the degree of deacetylation of the chitosan varies from 40 to 100%, in particular 50 to 100%, in particular 60 to 100%, in particular 95 to 100%, in particular 70 to 100%, in particular 80 to 100%, in particular 90 to 100%, in particular 40 to 90%, in particular 40 to 80%, in particular 40 to 70%, in particular 40 to 60%, in particular 40 to 50%, in particular 50 to 90%, in particular 50 to 80%, in particular 50 to 70% %, in particular 50 to 60%, in particular 60 to 90%, in particular 60 to 80%, in particular 60 to 70%, in particular 70 to 90%, in particular 70 to 80%, in particular 80 to 90%. In a preferred embodiment, the degree of deacetylation is >50%, in particular >90%.

In a particularly preferred embodiment of the present invention, the chitosan or chitosan derivative is present as a chitosan oligomer.

In a particularly preferred embodiment of the present invention, the chitosan oligomer has a molecular weight of 1 to 50 kDa, in particular 2 to 40 kDa, in particular 1 to 20 kDa, in particular 1 to 2 kDa, in particular 2 to 20 kDa or in particular 5 to 20 kDa on.

In a particularly preferred embodiment of the present invention, the chitosan or chitosan derivative is present as a chitosan polymer.

In a particularly preferred embodiment of the present invention, the chitosan polymer has a molecular weight of 51 to 400 kDa, in particular 51 to 200 kDa, in particular 60 to 100 kDa, in particular 65 to 90 kDa, in particular up to 100 to 200 kDa or in particular 200 to 400 kDa on.

In a particularly preferred embodiment of the present invention, the chitosan or chitosan derivative is in the chitosan-containing solution in a concentration of 0.001 to 10%, in particular 0.001 to 1%, in particular 0.01 to 5%, in particular 0.01 to 3%. 0.01 to 1%, in particular 0.05 to 1%, in particular 0.1 to 1%, in particular 0.5 to 1%, in particular 0.1 to 0.5%, in particular 0.01 to 0.1% , in particular 0.01 to 0.9% (in each case w/v) before.

In a particularly preferred embodiment, the chitosan can be present in an aqueous solution, in particular in a buffered aqueous solution, in particular in an acidic buffered solution, in particular in a phosphate-buffered solution. In a preferred embodiment, the chitosan can be present in an acidic aqueous solution, for example in an aqueous solution with a pH of 1 to 6.9, in particular 2 to 6, in particular 3 to 5.5.

In a particularly preferred embodiment, the chitosan-containing solution can be present as an aqueous solution, in particular as a buffered aqueous solution, in particular an acidic buffered solution, in particular a phosphate-buffered solution. In a preferred embodiment, the chitosan-containing solution can be present as an acidic aqueous solution, for example as an aqueous solution with a pH of 1 to 6.9, in particular 2 to 6, in particular 3 to 5.5.

In a particularly preferred embodiment of the present invention, the chitosan-containing solution includes other additives. The additives are preferably small, Molecules bearing carboxyl groups such as acetic acid and/or citric acid or higher molecular weight polymers bearing carboxyl groups.

In a particularly preferred embodiment of the present invention, at least two different chitosan-containing solutions, in particular at least three, in particular at least four, are provided in method step a).

In a particularly preferred embodiment of the present invention, exactly one chitosan-containing solution is provided in method step a), in particular exactly two, in particular exactly three, in particular exactly four.

In a particularly preferred embodiment of the present invention, if at least two different chitosan-containing solutions are provided, the chitosan-containing solutions are applied in method step b) simultaneously or one after the other.

In a particularly preferred embodiment of the present invention, the liquid adhesive formulation is a suspension, a dispersion, an emulsion or a solution of at least one adhesive.

In a particularly preferred embodiment, in addition to the at least one adhesive, the adhesive formulation can contain at least one other agent selected from the group consisting of synthetic or natural polymers, plasticizers, resins, preservatives, dispersants, fillers, light stabilizers, defoamers, rheology improvers, thickeners, crosslinkers, hardeners and have combinations thereof.

In a particularly preferred embodiment of the present invention, the liquid adhesive formulation is a suspension of at least one adhesive.

In a particularly preferred embodiment of the present invention, the liquid adhesive formulation is a dispersion of at least one adhesive.

In a particularly preferred embodiment of the present invention, the liquid adhesive formulation is an emulsion of at least one adhesive.

In a particularly preferred embodiment of the present invention, the liquid adhesive formulation is a solution, in particular an aqueous solution, of at least one adhesive.

In a particularly preferred embodiment of the present invention, the adhesive formulation comprises a physically-curing adhesive.

In a particularly preferred embodiment of the present invention, the adhesive formulation has a chemically curing adhesive.

In a preferred embodiment of the invention, the adhesive formulation contains at least one adhesive that is customarily used in paper and print processing, for example adhesives based on natural or semi-natural polymers, starch adhesives containing potato, corn, wheat, cassava, Tapioca and rice starch in native or degraded form, in different degrees of degradation, in cold or warm soluble form, with different degrees of gelatinization, dextrin adhesives, produced by thermal or chemical degradation of potato, corn, wheat, cassava, tapioca and Rice starch, gluten glues, starch/dextrin mixed glues, cellulose glues or cellulose derivative glues.

Adhesives based on synthetic polymers can also be used, for example hot-melt adhesives based on vinyl acetate (hot-melt adhesives), reactive polyurethane hot-melt adhesives (PUR reactive adhesives), polyvinyl alcohol adhesives, or dispersion adhesives containing homo- or copolymers of vinyl acetate , ethyl vinyl acetate, acrylates, styrene acrylate and dispersion adhesives containing polyurethane.

A dispersion adhesive formulation within the meaning of the invention can be a dispersion of an organic base, for example a polymer or copolymer of vinyl esters or acrylates, in liquid dispersants in which the organic base is insoluble. The dispersion can optionally contain plasticizers, resins or fillers.

In a preferred embodiment of the invention, the adhesive formulation is a dispersion adhesive formulation, in particular on an aqueous basis. Water-based dispersion adhesive formulations contain water as the solvent portion of the formulation. The dispersion adhesive formulation particularly preferably contains homo- or copolymers of vinyl acetate, ethyl vinyl acetate, acrylates, styrene acrylate or a polyurethane.

A very particularly preferred adhesive formulation is ^Emuldur® (BASF, Ludwigshafen, Germany), (anionic polyester-polyurethane in aqueous dispersion), ^Adhesin® A7362 (Henkel, Düsseldorf, Germany), (polyvinyl acetate) or Acronal® ^A508 (BASF, Ludwigshafen, Germany ), (acrylic acid ester copolymer dispersion) or one that consists partly or entirely of bio-based or renewable raw materials.

In a particularly preferred embodiment of the present invention, the adhesive is an adhesive selected from the group consisting of epoxy resin, phenol-formaldehyde resin. Polyurethane, methyl methacrylate, cyanoacrylate, PVC (polyvinyl chloride), polycarbonate, polysulfide, silicone, unsaturated polyester, glutin, casein, starch, methyl cellulose, polyimide, vinyl ester resin, polychloroprene, and a combination thereof.

In a particularly preferred embodiment of the present invention, the adhesive formulation is a glue, in particular a cold glue, in particular cold glue made from bio-based or renewable raw materials.

In connection with the present invention, a glue is a suspension, dispersion, emulsion or solution of an adhesive, in particular made from animal, vegetable or synthetic raw materials, in a liquid medium, in particular in water.

In connection with the present invention, a cold glue is understood as meaning a glue that can be processed cold, in particular at room temperature (19 to 21° C.), without heating.

In a particularly preferred embodiment of the present invention, at least two different adhesive formulations, in particular at least three, in particular at least four, are provided in process step a).

In a particularly preferred embodiment of the present invention, exactly one liquid adhesive formulation is provided in method step a), in particular exactly two, in particular exactly three, in particular exactly four.

In a particularly preferred embodiment of the present invention, if at least two different adhesive formulations are provided, the adhesive formulations are applied simultaneously or one after the other.

In a particularly preferred embodiment, the chitosan-containing solution in method step b) can be applied manually, for example with a brush or sponge, or in a further preferred embodiment, by machine, for example with a nozzle or roller machine. In a particularly advantageous manner, the roller of the rolling machine can be constructed from a foam which, in a preferred embodiment, is half immersed in a basin containing the chitosan-containing solution so that the pores of the foam can be filled with the chitosan-containing solution. In a preferred embodiment, the chitosan-containing solution is applied to the at least one surface to be bonded on the at least one fiber-containing surface of the first element with the other half protruding from the basin.

In a particularly preferred embodiment, the adhesive formulation in method step c) can be applied manually, for example with a brush or sponge, or in a further preferred embodiment by machine, for example with a nozzle or roller machine.

In a particularly preferred embodiment, the invention also relates to a device that is suitable, in particular set up, for carrying out a method according to the invention.

1. a) eine Einspanneinheit zum Einspannen mindestens eines ersten mindestens eine Faser-haltige Oberfläche aufweisenden Elements, insbesondere eine Buchblockzange,
2. b) eine Faserfreilegungsvorrichtung zur Oberflächenvergrößerung, insbesondere Aufrauvorrichtung zum Aufrauen, mindestens einer zu verklebenden Fläche des mindestens einen ersten mindestens eine Faser-haltige Oberfläche aufweisenden Elements,
3. c) einen ersten Applikator, insbesondere eine Düse oder Walzeinheit, zum Aufbringen einer Chitosan-haltigen Lösung aus einem ersten Vorratsbehälter auf die mindestens eine zu verklebende Fläche und
4. d) einen zweiten Applikator zum Aufbringen einer flüssigen Klebstoffformulierung aus einem zweiten Vorratsbehälter auf die mit der Chitosan-haltigen Lösung vorbehandelte Klebezone.

In a particularly preferred embodiment, the invention also relates to a device for producing a product having at least two elements glued to one another, comprising

1. a) a clamping unit for clamping at least one first element having at least one fiber-containing surface, in particular book block clamps,
2. b) a fiber exposure device for surface enlargement, in particular a roughening device for roughening at least one surface to be bonded of the at least one first element having at least one fiber-containing surface,
3. c) a first applicator, in particular a nozzle or roller unit, for applying a chitosan-containing solution from a first reservoir to the at least one surface to be bonded and
4. d) a second applicator for applying a liquid adhesive formulation from a second reservoir to the adhesive zone pretreated with the chitosan-containing solution.

1. a) eine Einspanneinheit zum Einspannen eines Papierstapels, insbesondere eine Buchblockzange,
2. b) eine Faserfreilegungsvorrichtung zur Oberflächenvergrößerung, insbesondere Aufrauvorrichtung zum Aufrauen, mindestens einer zu verklebenden Fläche des Papierstapels,
3. c) einen ersten Applikator, insbesondere eine Düse oder Walzeinheit, zum Aufbringen einer Chitosan-haltigen Lösung aus einem ersten Vorratsbehälter auf die mindestens eine zu verklebende Fläche und
4. d) einen zweiten Applikator zum Aufbringen einer flüssigen Klebstoffformulierung aus einem zweiten Vorratsbehälter auf die mit der Chitosan-haltigen Lösung vorbehandelte Klebezone.

In a particularly preferred embodiment, the invention also relates to a device for adhesive binding of paper products, comprising

1. a) a clamping unit for clamping a stack of paper, in particular a book block clamp,
2. b) a fiber exposure device for surface enlargement, in particular a roughening device for roughening at least one surface of the paper stack to be glued,
3. c) a first applicator, in particular a nozzle or roller unit, for applying a chitosan-containing solution from a first reservoir to the at least one surface to be bonded and
4. d) a second applicator for applying a liquid adhesive formulation from a second reservoir to the adhesive zone pretreated with the chitosan-containing solution.

In a particularly preferred embodiment, the device for producing a product having at least two elements glued to one another, in particular for adhesive binding of paper products, has a further device for bringing the at least one second element into contact with the adhesive zone of the at least one first element.

In a particularly preferred embodiment, the at least one second element is manually brought into contact with the adhesive zone of the at least one first element.

In a particularly preferred embodiment of the present invention, the area to be bonded on the fiber-containing surface is subjected to a surface enlargement, in particular an exposure of fibers, in a method step al) before carrying out method step b). This is particularly advantageous if, according to a preferred embodiment, the fibers of the fiber-containing surface are present in a fiber composite, i.e. in particular the fibers are either arranged directly physically adjacent to one another, preferably over their entire length, for example are pressed, and/or or are embedded in optionally present further components of the element, in particular its surface, for example in a matrix.

In a preferred embodiment, method step a1) represents a roughening of the surface, in particular an exposure of fibers, in particular an exposure of fibers is carried out if paper or cardboard represents the fiber-containing surface.

Process step al) preferably takes place after process step a) and before process step b).

According to the invention, it is preferably provided that the surface area of the at least one fiber-containing surface of the first element, in particular the area to be bonded, is enlarged. In a preferred embodiment, this occurs in that the fibers present in the fiber-containing surface, preferably in a fiber composite, of the first element provided in method step a) are completely or partially exposed by the surface enlargement, ie fiber exposure takes place.

The surface of a fiber-containing surface of an element is formed by the areas of the surface, i.e. surfaces of the fibers and optionally other areas of the surface, for example other components of the surface, which are not connected, in particular in physical contact with one another, i.e to fibers or components of the element, and these areas of the surface are thus available for contacting, in particular wetting, with the chitosan-containing solution. The surfaces of the fibers available for contacting with the chitosan-containing solution can, in the case of exposed fibers, be almost the entire surface of the exposed fibers or, in the case of fibers that are, at least partially, in the fiber composite, those parts of the fiber surface that not in contact with other fibers or components of the element.

The area of the fiber-containing surface is enlarged by exposing fibers from a fiber composite of a fiber-containing surface.

In a particularly preferred embodiment of the present invention, almost all, in particular all, fibers of the fiber-containing surface of the first element provided in method step a) are present in a fiber composite.

The fibers of the fiber-containing surface are exposed from the fiber composite and thus increase the surface area available for contact with the chitosan-containing solution.

In a particularly preferred embodiment, more than 50%, more than 60%, more than 70%, more than 80% or more than 90%, in particular more than 95%, of the fibers are exposed within the area to be bonded.

In connection with the present invention, an increase in surface area means that the area to be bonded is increased by at least 100%, in particular by at least 150%, in particular by at least 200%, in particular by at least 300%, in particular 100 to 450%, in particular by 150 to 450%, in particular by 200 to 450%.

The extent of the surface enlargement of the area to be bonded can be determined by means of microscopy, in particular light microscopy or electron microscopy. For this purpose, before and after the surface enlargement, the number of exposed fibers or fiber parts per unit area, as well as their dimensions, in particular the length and the diameter, are recorded and the respective size of the surface is calculated with the help of these dimensions.

In a particularly preferred embodiment, the increase in surface area is measured using a light microscope. Here, the length and the diameter of the exposed fibers, any partially exposed areas of fibers and any other areas present on a fiber-containing surface are measured. Assuming that a fiber resembles a cylinder, the surface area of a cylinder representing the fiber is calculated for each fiber based on the determined length and calculated from the diameter of the fiber. The average diameter of a representative sample of fibers can be used for the calculation as the diameter for the calculation.

The sum of the surface areas of the individual cylinders, i.e. the exposed fibers, exposed areas of fibers and any other areas of the surface that may be present, gives the size of the roughened surface and is compared with the sum of the surface area of any exposed fibers, of exposed areas of fibers as well as any other areas of the surface that may be present, ie preferably only the flat, two-dimensionally appropriate surface of the fiber composite, compared to an untreated surface.

The surface enlargement, also referred to as roughening in connection with the present invention, can be achieved, for example, by means of roughening devices, for example milling devices, rollers or disks, in particular having knives or teeth.

In a particularly preferred embodiment, the roughening can be achieved by means of plate-like roughening devices, in particular tools, these preferably providing plate-like tool disks with small elevations, in particular teeth, which preferably roughen the surface to be roughened during parallel rotation and thus achieve a fiber exposure.

In a particularly preferred embodiment of the present invention, the product produced by the method and having at least two elements glued to one another is a book, a brochure, a writing pad, a prospectus, a catalogue, a periodical or a magazine.

In a particularly preferred embodiment of the present invention, according to which the product is a book, brochure, pad, prospectus, catalogue, journal or magazine, the first element is a paper page and the second element is a spine, for Example book spine, inserted paper spine, as well as other elements other paper pages.

In connection with the present invention, the term "product" means in particular a paper product, in particular products that are Assembling of the above paper are created, so for example products or intermediate products of bookbinding, such as books, brochures, leaflets, magazines, catalogs, writing pads, book blocks, covers and magazines.

In a particularly preferred embodiment of the present invention, the product produced using the method and having at least two elements glued to one another is a book, in particular a photo book.

The method according to the invention is preferably used in print finishing. The term print processing includes all work steps through which the intended products with their respective shapes and properties are manufactured from printed or unprinted preliminary products. In particular, this means processes and steps in bookbinding that involve gluing, for example the adhesive binding of books, brochures, catalogues, writing pads, gluing, block gluing, hanging in book blocks, gluing covers, making book covers, endpaper gluing, spine gluing, side gluing, Back-gluing, gluing in cards and product samples, lamination, gumming, self-adhesive gumming, adhesive gumming or label production.

In a particularly preferred embodiment of the present invention, the method according to the invention is carried out as part of a lay-flat method.

In connection with the present invention, a lay-flat process is understood to mean that the paper pages of a book, journal or magazine, for example, are glued together in such a way that the respective product can be opened completely and the two visible pages can be completely opened, which means in an angle of 180°, can be unfolded and form a flat surface.

In a particularly preferred embodiment, the invention also relates to a bonded product having at least one fiber-containing surface that can be produced using a method according to the invention.

Further advantageous configurations emerge from the dependent claims.

The invention is explained in more detail using the following examples and exemplary figures.

characters

figure 1

shows a first element (10) provided according to the invention and having at least one fiber-containing surface (11) designed as a paper edge (150) with fibers (12) present in a fiber composite (17).

figure 2

shows the first element (10) having at least one fiber-containing surface (11) following a surface enlargement preferred according to the invention. figure 2 shows in particular that the fibers (12) were exposed by the increase in surface area.

figure 3

shows the first element (10) having at least one fiber-containing surface (11), with exposed fibers (12), after the addition of the chitosan-containing solution (20) to the zone to be bonded. The interaction of the chitosan (20) with the exposed fibers (12) in the adhesive zone (13) is shown schematically.

figure 4

shows the liquid adhesive formulation (30) applied to the adhesive zone (13) of the element (10) before mounting.

figure 5

shows the adhesive zone (13) after application of the liquid adhesive formulation (30). The liquid adhesive formulation lies homogeneously in the interstices (31) between the exposed fibers (12) and the chitosan (20).

figure 6

shows by way of example the product (50) having two elements glued together, comprising a first element (10) having at least one fibrous surface, a second element (40) and the adhesive zone (13).

figure 7

shows schematically in time sequences the behavior of adhesive (30) applied to a paper edge (150) having exposed fibers (12) without using chitosan (20) (left) and using chitosan (right) (time 1: immediately after application of the adhesive, point in time 2: later point in time).

figure 8

schematically shows a device for adhesive binding of paper products comprising a clamping unit (book block clamp) (6), application rail/transport section (2), fiber exposure device, in particular roughening device (milling tool) (3), first applicator (activator application) (7) and second applicator (glue application) (8) and a first reservoir (4) associated with the first applicator (7) and a second reservoir (5) associated with the second applicator (8).

Reference List

1

book block (paper stack)

2

Application rail/transport route

3

Fiber exposure device (milling tool)

4

First reservoir

5

Second reservoir

6

clamping unit (book block clamp)

7

First applicator (activator order)

8th

Second applicator (glue application)

10

First element having a fibrous surface

11

fibrous surface

12

fibers

13

adhesive zone

17

fiber composite

20

chitosan

30

Liquid adhesive formulation

31

spaces between the fibers

40

second item

50

product

150

paper edge

examples Example 1: Production of adhesive bindings

A book block (DIN A4, ie with a spine length of 297 mm) was clamped in book block pliers so that the edge to be bound protrudes about 2 mm from the pliers (so-called notice). This book block was roughened by a milling device (from 1 and 2 shown schematically). This pre-treatment exposes the fibers and increases the surface area by around 300%. Then, for example, a 0.1% (m/v) chitosan-containing solution, with a chitosan with >50, in particular >90% degree of deacetylation in the solution (aqueous phosphate-buffered solution), is applied to the roughened book block spine (schematic according to figure 3 ). Immediately without drying the chitosan solution applied to the adhesive zone, an adhesive dispersion based on styrene acrylate is applied "wet on wet" via a nozzle in a book gluing machine of the Ribler Junior Binder or Ribler Express Binder type (manufacturer Ribler, Stuttgart, DE) (schematic diagram according to figures 4 and 5 ).

The adhesive dispersion had a practicable index for the viscosity (measured with a Ford cup, 5 mm nozzle) of preferably >100 s.

The book block is then bound into a book block spine (schematic figure 6 ) and get a book.

figure 7 shows the effect of applying chitosan (20) to a paper edge (150). figure 7 indicates that without the use of chitosan (20) ( figure 7 , left) on a paper edge (150) to be glued, the adhesive (30) remains on the paper edge and does not penetrate into the gaps (31) between the exposed fibers (12), but dries there (point in time 2). If, on the other hand, the paper edge (150) is provided with a chitosan-containing solution (20) before the adhesive (30) is applied and an adhesive zone (13) containing a chitosan-containing solution is thus obtained, the adhesive (30) sinks "wet on wet". in the edge of the paper and is distributed homogeneously in the gaps (31) ( figure 7 , right) (time 2).

Example 2: Assessment of cohesive fracture (KOH) and adhesive fracture (ADH)

Book blocks, each 2 cm thick, made from different types of paper (No. 1 to No. 5) were glued together as described in Example 1. As a control, book blocks without chitosan pretreatment, also 2 cm thick, were roughened analogously to the methods described above and in a binding machine of the Ribler Junior Binder or Ribler Express Binder type (manufacturer Ribler, Stuttgart, DE) via a nozzle with the nozzle described above Adhesive formulation bonded.

To assess adhesion and cohesion, the adhesive bond was opened flat and viewed under a light microscope. A sheet edge was pulled to stretch the glue seam. If the adhesive separates from the paper fiber, this is an adhesive failure. If, on the other hand, the adhesive does not tear on the paper fiber but within the adhesive seam, this is a cohesive failure.

When examining the book blocks of the controls with a light microscope, it is easy to see that the adhesive detaches relatively easily from the fiber (adhesive failure). If the spine of the book block was previously treated "wet in wet" with a chitosan-containing solution, as described in example 1, a cohesive fracture can be seen under the microscope, i.e. the adhesive film separates in the middle and adhesive residues remain hanging on the fiber.

Control experiments with no chitosan in the solvent did not result in adhesive bonding comparable to properties obtained using chitosan solutions.

Claims (16)

1. Process for producing a product (50) having at least two elements bonded together comprising

   a) providing at least one first element (10) having at least one fibre-containing surface (11), at least one second element (40), at least one chitosan-containing solution (20) and at least one liquid adhesive formulation (30),

   b) applying the at least one chitosan-containing solution to at least one area to be bonded on the at least one fibre-containing surface (11) of the first element (10) to obtain a pre-treated bonding zone (13) comprising the chitosan-containing solution (20) on the first element (10),

   c) applying the at least one liquid adhesive formulation (30) to the adhesive zone (13) comprising the pre-treated chitosan-containing solution (20) obtained according to process step b), and

   d) bringing the at least one second element (40) into contact with the adhesive zone (13) of the first element (10) to obtain the bonded product (50).
2. Process of claim 1, wherein the first, second, further or all elements are cellulosic products.
3. Process according to claim 2, wherein said first element (10) having at least one fibre-containing surface (11) is selected from the group consisting of paper, cardboard, wood, plant fibre materials, natural fibres, wound dressings, textiles, hygiene articles, absorber/adsorber materials or combinations thereof.
4. Process according to any one of the preceding claims, wherein the second element (40) is selected from the group consisting of plastic element, paper, cardboard, wood, plant fibre materials, natural fibres, wound dressings, textiles, hygiene articles, absorber/adsorber materials or combinations thereof.
5. Process according to any one of the preceding claims, wherein the elements are made of different or the same materials.
6. Process according to any one of the preceding claims, wherein the chitosan is chitosan or a chitosan derivative.
7. Process according to any one of the preceding claims, wherein the chitosan is in the form of an oligomer or a polymer.
8. Process according to any one of the preceding claims, wherein the adhesive formulation (30) comprises a physically curing adhesive or a chemically curing adhesive.
9. Process according to any one of the preceding claims, wherein the adhesive formulation (30) is a cold glue.
10. Process according to any one of the preceding claims, wherein the chitosan-containing solution (20) has a chitosan concentration of from 0.001 to 10 % (m/v).
11. Process according to any one of the preceding claims, wherein in a process step a1) the surface to be bonded is subjected to surface enlargement before carrying out process step b).
12. Process according to any one of the preceding claims, wherein the first element is a paper sheet and the second element is a paper back.
13. Process according to any one of the preceding claims, wherein the product is a book.
14. Process according to any one of the preceding claims, wherein the process is carried out as part of a lay-flat process.
15. Bonded product (50) having at least one fibre-containing surface, the product being made according to any one of the processes of claims 1 to 14.
16. Apparatus for producing a product (50) having at least two elements bonded together, comprising

    a) a clamping unit (6) for clamping at least one first element (10) having at least one fibre-containing surface (11), in particular a book block gripper,

    b) a fibre exposure device (3) for increasing the surface area of at least one area to be bonded of the at least one first element (10) having at least one fibre-containing surface (11),

    c) a first applicator (7), in particular a nozzle or roller unit, for applying a chitosan-containing solution (20) from a first reservoir (4) to the at least one surface to be bonded, and

    d) a second applicator (8) for applying a liquid adhesive formulation (30) from a second reservoir (5) to the adhesive zone (13) pretreated with the chitosan-containing solution (20).

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