Adhesive formulation for producing pressed material bodies

Abstract

The present invention relates to a chemically curable aqueous adhesive formulation for producing press material bodies, particularly press material plates. The adhesive formulation has an aqueous phase of 35 to 85% by weight of a hydroxy-functionalized reactive resin or a mixture of hydroxy-functionalized reactive resins. The adhesive formulation also has an aqueous phase of 12 to 25% by weight of a urea resin crosslinker, which is a reaction product of urea and a polyfunctional aldehyde. The adhesive formulation also contains 0.1 to 4% by weight of an acid catalyst. The present invention also relates to a method for producing press material bodies, particularly press material plates, using such an adhesive formulation.

Description

[Technical field]

[0001] The present invention relates to a chemically curable, aqueous adhesive formulation for producing pressing material bodies, in particular pressing material plates, and to a method for producing pressing material bodies, in particular pressing material plates, by continuous or discontinuous compression of a mixture of the adhesive formulation and chip or fiber material or by compressing a layer of the adhesive formulation and chip or fiber material. [Background technology]

[0002] The term "pressed material molding" generally refers to a molding that is formed into a pressed material molding by bonding a material with chip material or fiber material while curing a mixed adhesive compound, applying a pressing pressure, and possibly heating. The most common application of such moldings is in the form of a plate. Thus, the term "pressed material molding" includes, for example, chipboard, especially coarse chipboard (also called oriented strand board; OSB), medium density (wood) fiberboard (so called MDF board), high density (wood) fiberboard (so called HDF board), and also laminated or layered board structures, such as, for example, plywood.

[0003] Chip or fibrous materials therefore include very common materials, such as waste paper, other recycled materials such as sawdust, fibers such as wood or cellulose fibers, including fibers from recycled building materials, other naturally occurring fibers such as straw, bamboo, etc., and also synthetic fibers, such as polyester fibers. Of course, mixtures of fibers of different natures are also included in chip or fibrous materials. The chip or fibrous materials can be of completely different shapes and have completely different degrees of crushing. That is to say, the chip or fibrous materials can be present as a fiber composite that is already formed, such as, for example, in the above-mentioned veneer board. However, the chip or fibrous materials can also be provided in a more or less disintegrated form with different degrees of crushing, either with a relatively small degree of crushing, such as the so-called chips, for example in the above-mentioned chipboards or OSB, or also with a relatively high degree of crushing, such as, for example, the melted so-called wood flour, for example in the above-mentioned MDF and HDF boards.

[0004] Regardless of the type of chip material or fiber material, what is common to the (various) methods for producing pressed material bodies is that the fiber material with the adhesive compound is pressed in a mold under pressure and possibly heat.

[0005] The adhesive formulations for these applications mentioned above are generally known, and these known adhesive formulations must of course be adapted depending on the type of molding or plate to be produced and therefore depending on the process to be applied. In some cases, chemically very different adhesive formulations are used for the various processes. For example, when producing so-called fiberboards, mainly urea-formaldehyde resins, so-called UF resins, and also to a lesser extent isocyanate-based resins, are used, while for bonding or gluing veneer layers, mainly phenolic resins are used. This need to adapt the adhesive formulation to a given process and / or product can have economical disadvantages.

[0006] Moreover, in the process for producing press moldings, the adhesive formulations that are mainly used today have in common that harmful substances are released, especially during the curing process. Examples of such pollutants include, in particular, volatile components and decomposition products of formulations based on formaldehyde and isocyanates. In particular, attempts have already been made to at least reduce the amount of pollutants that can be released in the adhesive formulations that are mainly used, but other problems, in particular process engineering problems, often arise in the formulation of such low-polluting substances.

[0007] For example, in the case of producing pressed material pieces, the working times must be sufficiently short in order for the process to be economically viable. Therefore, in the processes mainly used today, the pressing of chip or fiber material with adhesive is carried out at high temperatures. The production of chipboards or fiberboards is generally carried out at temperatures of 200° C. to 250° C. This high temperature is therefore necessary, in particular, in order to obtain sufficient, as far as possible complete curing in the core of the press mix, since, for example, the heating of the press cake consisting of chip or fiber material and adhesive takes place from the side and the heat must be transferred into the inner core. Of course, this high temperature, in the adhesive formulations currently used, including the variants that reduce harmful substances, can often lead to damage to the moldings, for example, tearing of the moldings, and thus to a high defect rate. Patent Document 1 discloses an adhesive composition for plywood, which contains an emulsion-acrylic or methacrylic resin and an amine or phenolic resin. The amine resin can be formed, for example, by urea-formaldehyde resin or urea-melamine resin. Patent Document 1 lists (meth)acrylates having carboxyl or hydroxyl groups as the acrylic or methacrylic resin. US Patent No. 5,399, 667 discloses a synthetic resin dispersion-based water-based dispersion adhesive for bonding wood and other porous or semi-porous substrates. The synthetic resin dispersion comprises at least one emulsion polymer having a crosslinkable N-methylol group, at least one protective colloid and at least one crosslinking agent. The crosslinking agent may be selected from the group consisting of chemically modified urea derivatives, such as glyoxal diurea or malondialdehyde diurea. The solids content of the synthetic resin dispersion of US Patent No. 5,399, 667 may be about 50%. [Prior art document] [Patent documents] [Patent Document 1] Japanese Patent Application Publication No. 10-8014 [Patent Document 2] European Patent No. 1505085 Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to overcome the disadvantages of the prior art and to provide an adhesive formulation which allows the most reliable production of moldings possible, reduces the amount of contaminants in the process while avoiding a large number of rejects, and at the same time can be used as universally as possible in various production methods for pressed material moldings.It is also an object of the present invention to provide a method for producing pressed material moldings using such an adhesive formulation. [Means for solving the problem]

[0009] This problem is solved on the one hand by a chemically curable aqueous adhesive formulation for producing press material bodies, in particular press material plates, by continuous or discontinuous compression of a mixture of the adhesive formulation and chip material or fiber material, or by compression of a laminate of the adhesive formulation and fiber material plates.

[0010] The chemically curable water-based adhesive formulation comprises at least one chemically curable reactive resin and at least one crosslinker or curing agent for the reactive resin.

[0011] The chemically curable water-based adhesive formulations are specifically hydroxylated R of reactive resins functionalized with groups, or hydroxy R 35% to 85% by weight of an aqueous phase of a mixture of reactive resins functionalized with a group having a resin content of 30% to 65% by weight, 12% to 25% by weight of an aqueous phase of a urea resin crosslinker which is a reaction product formed from urea and a polyfunctional aldehyde having a resin content of 30% to 65% by weight, Ka % to 4 wt. % of an acid catalyst having a value of 2 or less.

[0012] Preferably, the chemically curable water-based adhesive formulation is a hydroxyl R of reactive resins functionalized with groups or functional hydroxyl groups R The aqueous phase may comprise 50% to 80% by weight of the mixture of reactive resins functionalized with groups. Preferably, the resin content of the aqueous phase may be between 35% and 60% by weight.

[0013] Preferably, the adhesive formulation may have an aqueous phase of 14% to 22% by weight of urea resin crosslinker. Preferably, the resin content of the aqueous phase may be 35% to 60% by weight.

[0014] In particular, the adhesive formulation may have from 0.5% to 3.5% by weight of an acid catalyst.

[0015] By aqueous phase is meant an aqueous dispersion and / or aqueous suspension and / or aqueous emulsion and / or aqueous solution of the reactive substances used, respectively, depending on the type of reactive substance used, and thus depending on the reactive resin and crosslinker / hardener, respectively. Here, the remainder can be formed at least mainly by water, in weight percent, thus up to 100% by weight of the aqueous phase. However, the aqueous phase can also have other components, such as, for example, dispersing and / or suspending aids or their stabilizers, emulsifiers, antifoaming agents, etc.

[0016] Furthermore, the adhesive formulation may contain other components or substances such as pigments or additives in addition to the specific aqueous phase. Examples of preferred additives are described in more detail below. Insofar as the adhesive formulation further contains other components, in particular additives, the skilled person must of course adjust the weight proportions of the specified aqueous phase (reactive resin, crosslinker) and acid catalyst accordingly.

[0017] The adhesive formulation may also be referred to as an adhesive formulation, a sizing agent or, as is customary in the relevant technical field, as a glue formulation. In particular, the adhesive formulation may be intended for use in the manufacture of chipboard, fiberboard and laminated board structures such as, for example, veneered wood boards.

[0018] The adhesive formulations having the characteristics described are characterized on the one hand by the fact that they can be used without emitting harmful substances. Experiments have shown that in the adhesive formulations described, in particular when the adhesive formulations are cured in the process of producing pressed material mouldings, no formaldehyde or isocyanate emissions occur. As a result, when using mainly wood fibre-based fibre materials, for example, the formaldehyde emissions can be limited or reduced compared to conventional adhesive formulations, at least compared to the amount of formaldehyde released by the wood fibre material itself. This means in the subsequent results that the advantage in terms of the emission of harmful substances during the production of pressed material mouldings or pressed material moulding plates and the associated significant improvement in, for example, working conditions.

[0019] Surprisingly, it has also been shown that the adhesive formulation of a certain composition can be used universally in the technical field of producing pressed material moldings without the need for substantial adaptation.Thus, for example, chipboards, MDF boards, HDF boards, OSB plates, laminated plates made of chip material or fiber material can be produced using this adhesive formulation, or similar production methods can be carried out using the adhesive formulation.

[0020] It has further been demonstrated that the temperature during the pressing process can be significantly reduced when using this adhesive formulation compared to conventional adhesive formulations according to the prior art: in experiments, for example when producing MDF boards, the temperature during the pressing process can be reduced to below about 160° C. when using this adhesive formulation, compared to temperatures of over 200° C., which are usually required when using conventional adhesive formulations. This quite fundamentally also leads to a reduction in energy costs and therefore to a reduction in production costs.

[0021] In this connection, the adhesive formulation has also been found to be advantageous with regard to the production of pressed material mouldings without or at least with reduced rejects. Apparently, when using the described adhesive formulation, on the one hand, good heat conduction from the outer region of the press cake, which consists, for example, of chip material or fibre material and adhesive formulation, is achieved, so that in the process of pressing such a press cake, in its core region, a sufficiently high core temperature can be achieved and as completely cured as possible. This can be confirmed in particular by the mechanical properties that can be achieved, such as, for example, the mechanical bending strength and / or transverse tensile strength of the moulding produced as a plate, which are clearly within or even exceed the standardised requirements for the respective plate, for example MDF board or HDF board. On the other hand, it appears that the relatively low temperatures required in the course of the pressing process to cure the adhesive formulation of the invention as completely as possible do not result in damage and thus prevent rejects.

[0022] In this adhesive formulation, hydroxy R of reactive resins functionalized with groups, or hydroxy R The mixture of reactive resins functionalized with groups has an active hydrogen equivalent in the aqueous phase of from 200 g / mol to 1500 g / mol.

[0023] Within this range, the active hydrogen equivalent is R It has been found to be particularly suitable for the curing reaction of functionalized reactive resins. R of reactive resins functionalized with groups or functional hydroxyl groups R The aqueous phase of the mixture of reactive resins functionalized with groups may have an active hydrogen equivalent weight of from 500 g / mol to 1300 g / mol.

[0024] As is known per se, the concept of functionalized resins refers quite generally to the elimination of the respective functional groups, in this case e.g. the hydroxy groups of reactive resins. R The groups can be understood as chemical substances which are present chemically bound to an oligomeric or polymeric carrier or to a hydrocarbon backbone. The nature of the carrier can, in principle, be of a diverse nature.

[0025] Preferably, hydroxy R Reactive resins or hydroxyl groups functionalized R The mixture of reactive resins functionalized with groups can be selected from the group consisting of acrylate resins, functionalized styrene acrylate resins, functionalized acrylic acid copolymers, functionalized acrylate-urethane copolymers and functionalized (meth)acrylate copolymers.

[0026] Each was used, hydroxy R Depending on the type of resin or polymer functionalized with the hydroxyl group, the corresponding aqueous phase can be prepared, for example, as an aqueous dispersion, suspension, emulsion or solution. R Examples of suitable aqueous phase functionalized reactive resins include Macrynal SC 6826 WA42 and Viacryl SC 6843WA42 from Allnex and AC31 from Alberdingk Boley.

[0027] Hydroxy R An example of a suitable aqueous phase urea resin crosslinker or hardener for functional reactive resins is the product Cymel NF3030 from Allnex.

[0028] As the acid catalyst, for example, sulfonic acids such as (modified) p-toluenesulfonic acid and its derivatives can be used, and a suitable example is Cycat 4045 from Allnex.

[0029] In a preferred embodiment variant, the adhesive formulation may contain from 0.1% to 20% by weight of one or more polyhydric alcohols.

[0030] The use of one or more polyhydric alcohols within a certain weight percentage range can effectively prevent or delay, in particular when necessary, premature or very rapid curing of the adhesive formulation. The polyhydric alcohol acts as a reaction retarder in certain reactive resins or hardeners / crosslinkers of the adhesive formulation. This means that the necessary mixing with chip or fiber materials and / or coating of boards containing chip or fiber materials can be carried out without a high risk of premature curing. This feature is particularly useful in processes in which the adhesive formulation is mixed with chip or fiber materials at elevated temperatures, such as, for example, in so-called blowlines. It has proven to be particularly effective if the adhesive formulation has 1% to 10% by weight of one or more polyhydric alcohols. As polyhydric alcohols, glycols such as, for example, butyl diglycol can be used.

[0031] In a further embodiment, the adhesive formulation may contain 0.1% to 5% by weight of an anionic or neutral wax, or a mixture of these waxes.

[0032] This in particular makes it possible to improve the adhesion of chip or fibrous materials and therefore the mixing with chip or fibre materials or the lamination of chip or fibrous boards. Preferably, the adhesive formulation contains 0.5% to 3% by weight of an anionic or neutral wax or a mixture of these waxes. As a wax or wax mixture, for example the product Hydrowax 46 from Sasol is suitable.

[0033] As an alternative to one or more waxes as components of the adhesive formulation, solid waxes can also be added in the process of adhering the chip or fiber material by adhesive mixing, as described in more detail below using the method for producing a pressed material compact.

[0034] Other embodiments of the adhesive formulation may include from 0.1% to 35% by weight of one or more fillers and / or pigments.

[0035] By means of the fillers and / or pigments it is finally possible to adjust the mechanical properties and / or the colour of the pressed material body.

[0036] Additionally, it may be effective for the adhesive formulation to have from 0.1% to 6% by weight of one or more wetting agents or surfactants.

[0037] This feature makes it possible, inter alia, to improve the handling of the aqueous phase and to improve the adhesion properties of the adhesive formulation. A suitable wetting agent is for example Disperbyk 190 from Byk.

[0038] Additionally, the adhesive formulation may include 0.1% to 8% by weight of one or more antifoaming agents.

[0039] This feature can have an advantageous effect on the pressing process, in particular in the production of pressed material bodies, for example to prevent the formation of bubbles. Suitable defoamers include, for example, Surfynol 420 or Surfynol DF 75 from Evonik.

[0040] The adhesive formulation may further comprise from 0.1% to 8% by weight of one or more thickeners.

[0041] Examples of suitable thickeners include Rheolate 310D from Elemenis and / or Acrysol RM 8W from Dow. By using thickeners of this type, the rheology and thus the processing properties, especially of two-component adhesive formulations, can be adjusted or adapted to requirements. In particular, adhesive formulations with thickeners are particularly suitable for forming coatings, for example by roller application.

[0042] Essentially, this adhesive formulation contains all the substances contained therein, thus the hydroxyl groups. R of reactive resins functionalized with groups, or hydroxy R The above-mentioned aqueous phase of the mixture of reactive resins functionalized with groups, the aqueous phase of the urea resin crosslinker, the acid catalyst, and possibly additional additives or ingredients are mixed into the formulation, which may have a limited shelf life, however.

[0043] Thus, preferably, the adhesive formulation comprises a hydroxy R of reactive resins functionalized with groups or functional hydroxyl groups R The mixture may include a first water-based component A having an aqueous phase of a reactive resin functionalized with a group, and a second component B having an aqueous phase of a urea resin crosslinker, and components A and B may be prepared to make an adhesive formulation by mixing components A and B.

[0044] In other words, the curable adhesive formulation can be produced by mixing the two components A and B, or the curable adhesive formulation can be produced by mixing the two components A and B. The mixing of components A and B can preferably be carried out immediately before use, and thus immediately before bonding the chip or fiber material and / or immediately before bonding the chip or fiber material boards, as will be explained in more detail below.

[0045] The adhesive formulation may, for example, consist of 60% to 90% by weight of component A and 10% to 40% by weight of component B. In other words, the adhesive formulation can be made or formed by mixing 60% to 90% by weight of component A and 10% to 40% by weight of component B.

[0046] In this case, component A or component B may also contain an acid catalyst. Furthermore, apart from the specific aqueous phase and the acid catalyst, other components or substances or additives, such as, for example, the additives mentioned above, may possibly be mixed into component A or component B. Insofar as component A and / or component B further contain other components, in particular additives, the skilled person must naturally adjust the appropriate weight ratios of components A and B. If component A and / or component B has other additives, the ratio of the weight % of component A to component B must also be adjusted within the weight % ranges specified above.

[0047] The object of the invention is also achieved by a first method for producing a pressing material body, in particular a pressing material plate.

[0048] The method comprises the following steps: - providing a chip or fibre material or a mixture of chip or fibre materials; - providing a chemically curable adhesive formulation; - mixing a chip or fiber material or a mixture of chip or fiber materials with an adhesive formulation to form a press cake; - Continuously compressing the presscake while the adhesive formulation is curing, or producing presscake pieces and discontinuously compressing the presscake pieces in the press mould while the adhesive formulation is curing.

[0049] It is important in this method that as adhesive formulation a chemically curable water-based adhesive formulation is used, as defined in claim 10. In this case the presscake or presscake pieces have a weight percentage of chip or fibre material or a mixture of chip or fibre material of 77% to 98.5% by weight and a weight percentage of the adhesive formulation of 1% to 20% by weight.

[0050] The advantages obtained by this type of method and by such a manufacturing method using a specific adhesive formulation have already been explained in connection with the above description of the adhesive formulation. When a two-part adhesive formulation is used, the corresponding two-part adhesive formulation can be formed in the manufacturing method by combining the two components A and B. The combining or mixing of the two components A and B can be carried out before or even during the step of mixing the chip or fiber material and / or the chip or fiber material mixture with the adhesive formulation to produce a press cake.

[0051] Chip or fibrous materials and chip or fibrous material mixtures are materials which contain fibres such as wood fibres or cellulose fibres, including fibres from waste paper, other recycled materials such as sawdust or recycled construction wood, other fibres of natural origin, such as straw, bamboo etc., and also synthetic fibres, such as polyester fibres. Chip or fibrous materials or chip or fibrous material mixtures can be entirely different in form, in particular with respect to the degree of crushing. Chip or fibrous materials or chip or fibrous material mixtures can be provided, for example, with a relatively small degree of crushing, such as so-called chips, for example in the above-mentioned chipboards or OSB, or also with a relatively high degree of crushing, such as so-called fused wood flour, for example in the above-mentioned MDF and HDF boards.

[0052] In a further embodiment of the method, 0.1% to 5% by weight of a solid wax can be added during mixing of the chip or fiber material or chip or fiber material mixture with the adhesive formulation.

[0053] This can in particular improve the adhesion of the chip or fiber materials or chip or fiber material mixtures and therefore the mixing of the adhesive formulation with the chip or fiber materials or chip or fiber material mixtures.

[0054] Finally, however, the object of the present invention is also achieved by a further method for producing a pressed material body, in particular a pressed material plate, which comprises the following steps: - providing a plate having a number of chip or fiber materials; - coating at least one surface of the plate intended for bonding to another plate with an adhesive compound, - stacking the coated plates to form a plate stack, - Compress the plate stack in a press mold while the adhesive compound cures.

[0055] It is again important that in this further method, as adhesive formulation a chemically curable adhesive formulation is used as defined in claim 12, where the weight percentage of the plates of the plate stack is between 80% and 99% by weight and the weight percentage of the adhesive formulation of the plate stack is between 1% and 20% by weight.

[0056] In order to better understand the invention, the invention is explained in detail below by means of non-limiting embodiments and also by means of the figures, the method for producing a pressing material plate.

[0057] Within the scope of the present invention, examples of compositions of chemically curable adhesive formulations are as follows: Ingredient A Macrynal SC6826 WA42; Allnex; 73.6% by weight, butyl diglycol; 5% by weight, Cycat 4045; Allnex, 2% by weight; Hydrowax 46; Sasol; 1% by weight; Component B Cymel NF3030, Allnex; 18.4% by weight.

[0058] In the examples given, the adhesive formulation is produced as a two-part adhesive formulation, the weight percentages of the individual components of the two-part adhesive formulation being based on 100% by weight of the two-part adhesive formulation consisting of component A and component B. Thus, in the examples given, component A consists of 90.2% by weight of Macrinal SC6826WA42, 6.1% by weight of Butyl Diglycol, 2.5% by weight of Cycate 4045 and 1.2% by weight of Hydrowax, relative to 100% by weight of component A. In the examples given, component B consists of 100% by weight of Cymel NF3030. In this example, the adhesive formulation consists of 81.6% by weight of component A and 18.4% by weight of component B.

[0059] As already mentioned above, such an embodiment of a two-part adhesive formulation is preferably used for improved storage properties, but in principle is a ready-mixed formulation with all the substances contained therein, and therefore hydroxyl groups are not included. R of reactive resins functionalized with groups or functional hydroxyl groups R Also possible is the embodiment of a mixture of reactive resins functionalized with groups as a ready-mixed formulation having an aqueous phase and an aqueous phase of a urea resin crosslinker and an acid catalyst and, optionally, additional additives or components.

[0060] Macrinal SC 6826 WA42 is a hydroxy R It is an aqueous phase or dispersion of a functionalized acrylic-polyol resin with 43% non-volatile matter by weight and an active hydrogen equivalent (HEW) of 900 g / mol.

[0061] Cymel NF3030 is the aqueous phase of the reaction product of urea and polyfunctional aldehydes, having a non-volatile matter content of about 43% by weight.

[0062] Cycate 4045 is a partially amine blocked p-toluenesulfonic acid catalyst.

[0063] The particular adhesive formulation has proven to be fundamentally good and universally suitable for use in the known methods for producing pressed material bodies.

[0064] However, the adhesive formulations described should be regarded as merely examples, and adapted or other formulations or recipes can be used instead of the adhesive formulations described above, depending on the respective specific requirements of the method for producing the pressed material bodies.

[0065] Thus, for example, the product Macrinal SC6826WA is a hydroxyl group-containing compound, e.g., Viacryl SC6834W, as well as Allnex, etc. R of reactive resins functionalized with groups, or hydroxy R It can be replaced by another aqueous phase of the mixture consisting of reactive resins functionalized with groups. R Reactive resins or hydroxyl groups functionalized R The mixture of reactive resins functionalized with groups can be selected from the group consisting of acrylate resins, functionalized styrene-acrylic resins, functionalized acrylic acid copolymers, functionalized acrylate-urethane copolymers and functionalized (meth)acrylate copolymers.

[0066] The same is true for the other components of the exemplary adhesive formulation described in the Examples above: Cymel NF3030, Butyl Diglycol, Cycate 4045 and Hydrowax 46.

[0067] Those skilled in the art will generally know products similar to those mentioned in the examples. Insofar as the adhesive formulation is produced as a two-component adhesive formulation, it also applies that instead of component A, the respective additives can also be added to component B, as described for butyl diglycol and Hydrowax 46 in the above examples.

[0068] Depending on the respective requirements or process controls, it may also be advantageous for the adhesive formulation to further comprise additives other than those described in the examples above, i.e. butyl diglycol and Hydrowax 46. For example, the adhesive formulation may have, for example, 0.1% to 35% by weight of one or more fillers and / or pigments, 0.1% to 6% by weight of one or more wetting agents, 0.1% to 8% by weight of one or more defoamers and / or 0.1% to 8% by weight of one or more thickeners. Furthermore, the adhesive formulation may contain 0.1% to 20% by weight of one or more polyhydric alcohols and 0.1% to 5% by weight of anionic or neutral waxes. As already mentioned, additives of this kind can in principle be added to component A or to component B if the adhesive formulation is produced in two components.

[0069] Depending on the type and amount of the additives, respectively, or depending on the general requirements and process control of the method for producing the pressed material bodies, the weight percentages of the components of the adhesive formulation, i.e., the aqueous phase, the acid catalyst(s), the polyhydric alcohol and the various additives, may of course be adjusted. In this case, the skilled person can make a corresponding adjustment of the weight percentages of the individual components, respectively, within the above-mentioned weight percentage ranges for the individual components. If produced as a two-component adhesive formulation, the weight percentages of components A and B relative to one another can of course likewise be appropriately adjusted within the specified weight percentage ranges.

[0070] In particular, water-soluble adhesive formulations are R of reactive resins functionalized with groups, or hydroxy R The aqueous adhesive formulation further comprises 35% to 85% by weight of a mixture of reactive resins functionalized with a group, the aqueous phase having a resin content of 30% to 65% by weight. The aqueous adhesive formulation further comprises 12% to 25% by weight of a urea resin crosslinker, the reactive product formed from urea and a multifunctional aldehyde, the aqueous phase having a resin content of 30% to 65% by weight. The aqueous adhesive formulation further comprises a p of 2 or less. Ka The acid catalyst has a value of 0.1% to 4% by weight.

[0071] Hydroxy R of reactive resins functionalized with groups or functional hydroxyl groups R The active hydrogen equivalent of the aqueous phase of the mixture of reactive resins functionalized with groups can be from 200 g / mol to 1500 g / mol.

[0072] In the following, an embodiment of the method for producing a pressing material plate is explained further with the aid of the figures, which are each highly schematic representations: [Brief description of the drawings]

[0073] [Figure 1] FIG. 1 illustrates an embodiment of a continuous pressing process of a press cake to form a press material plate. [Diagram 2] FIG. 2 shows an embodiment of a discontinuous pressing process for laminating layers of plates with chip or fiber material and adhesive compound. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0074] The method for producing a press material part, in particular a press material plate, essentially comprises the following steps: - Providing a chip material or fiber material or a chip material or fiber material mixture, - preparing a chemically curable adhesive formulation; - mixing the chip material or fiber material or the chip material or fiber material mixture with an adhesive formulation to form a press cake, - Pressing the presscake continuously while the adhesive formulation is curing, or producing pieces of presscake and discontinuously pressing the pieces of presscake in a press mould while the adhesive formulation is curing.

[0075] In this case, the adhesive formulation used may be a chemically curable, water-based adhesive formulation as described above and as defined in the corresponding claims.

[0076] The mixing of the chip or fiber material or chip or fiber material mixture with the adhesive formulation, also referred to in the technical term gluing, may be carried out in various ways, as is known per se. The most common methods in this respect are mechanical gluing or mixing in a mixing device, so-called blowline gluing and, more rarely, dry gluing. These gluing or mixing methods are known to those skilled in the art, so a detailed description here is not necessary. In this case, as an alternative to the example given above for a two-component adhesive formulation with wax (Hydrowax 46), 0.1 to 5% by weight of solid wax may be mixed in during the mixing of the chip or fiber material or chip or fiber material mixture with the adhesive formulation.

[0077] Insofar as a two-component adhesive formulation is used for this process, the adhesive formulation can be produced, for example, by mixing components A and B before or even in the course of mixing with the chip or fiber material.

[0078] Alternatively, after or by mixing the chip or fiber material or the chip or fiber material mixture with the adhesive formulation, a so-called press cake is formed or obtained, which is then compressed.

[0079] In FIG. 1 an embodiment of a continuous pressing process for a press cake 1 is shown. Such a continuous pressing process of the press cake 1 can be carried out in the embodiment shown in FIG. 1 by means of a double belt press 2. The double belt press 2 shown in the embodiment of FIG. 1 has a so-called underbelt 3, on which the press cake 1 is applied and transported, and an overbelt 4 as pressing member. The press cake 1 is guided between the underbelt 3 and the overbelt 4 of the double belt press 2 as shown in FIG. 1 and is compressed or pressed with the desired pressing pressure by adjusting the underbelt 3 and the overbelt 4 relative to each other. In the course of the compression of the press cake 1, the adhesive formulation also hardens, which can be initiated or accelerated by heating, for example by heating means 5 shown in FIG. 1.

[0080] 1 shows only one possible embodiment for the continuous pressing of the press cake 1, but other continuously operating pressing systems, such as presses with press rollers or presses with a belt-roller combination or so-called calender presses, are known per se and customary in the field of producing pressed material bodies. In the case of continuous pressing, as shown in FIG. 1, a pressed material strand 6 is obtained which can then be separated by being cut into pressed material bodies, in particular pressed material plates.

[0081] For example, instead of a continuous compression, as can be seen with the embodiment shown in Fig. 1, in the process it is also possible to discontinuously press pieces of press cake previously produced in the desired manner, obtained for example by dividing a continuously discharged press cake, to form a press material body whilst the adhesive compound is hardening. Such discontinuous compression can be carried out, for example, in a press mould with a displaceable press stamp.

[0082] Whether the process is carried out by continuous or discontinuous compression of the press cake or press cake pieces, the press cake or press cake pieces have a weight percentage of chip or fiber material or a mixture of chip or fiber material of from 77% to 98.5% by weight and a weight percentage of two-part adhesive formulation of from 1% to 20% by weight.

[0083] FIG. 2 shows, simply and roughly, an embodiment of an alternative method for producing pressing material bodies, in particular pressing material plates, in which the adhesive formulation according to the invention can also be used.

[0084] This alternative method comprises the following steps: - Providing a number of plates, in particular plywood, with chip or fibrous material, - coating at least one surface of the plate intended for bonding to another plate with an adhesive compound, - stacking the coated plates to form a plate stack, - Compress the plate stack in a press mold while the adhesive compound cures.

[0085] 2 shows a corresponding plate stack 7, in which plates 8 with chip material or fiber material are laminated with a layer of adhesive compound 9, each arranged between two plates 8. The plate stack 7, roughly shown diagrammatically in FIG. 2, can be compressed, for example, by means of a press stamp 10, possibly also in a press die, not shown in FIG. 2. Before compression, the plates 8 can be coated or glued with the adhesive compound 9, so that essentially one surface 11 of the plates or at least both surfaces 11 of the plates 8 located on the inside can also be coated with the adhesive dose 9.

[0086] In the process of compressing the plate stack 7 shown in FIG. 2, the adhesive composition 9 as described above can also be used as the adhesive composition, the weight percentage of the plates in the plate stack being 80% to 99% by weight and the weight percentage of the adhesive composition in the plate stack being 1% to 20% by weight.

[0087] It should be noted at this point that the embodiments illustrate possible implementation variations, whereby the present invention is not limited to the specifically illustrated implementation variations.

[0088] The protection area is defined by the claims. However, the description and the drawings should be used to consider the claims. Individual features or combinations of features of the various embodiments shown and described may represent independent inventive solutions in themselves. The problem underlying the independent inventive solution can be read off from the description.

[0089] All references to value ranges within the specific descriptions are intended to include any and all subranges thereof, e.g., the reference 1 to 10 is intended to include all subranges beginning with a lower limit of 1 and an upper limit of 10, i.e., all subranges beginning with a lower limit of 1 or more and ending with an upper limit of 10 or less, e.g., from 1 to 1.7, or from 3.2 to 8.1, or from 5.5 to 10.

[0090] Finally, it should be pointed out, for the sake of formality, that some of the components are not drawn to scale and / or are enlarged and / or reduced in size in order to make the structure easier to understand. The following are some embodiments of the present invention. [Aspect 1] 1. A chemically curable aqueous adhesive formulation for producing press material bodies, in particular press material plates, by continuous or discontinuous compression of a mixture of the adhesive formulation and chips and / or fiber material or by compression of a laminate of the adhesive formulation and chips and / or fiber material plates, having at least one chemically curable reactive resin and at least one crosslinker for the reactive resin; In things, The water-based adhesive formulation comprises a hydroxy R of reactive resins functionalized with groups, or hydroxy R 35% to 85% by weight of a mixture of reactive resins functionalized with groups, the aqueous phase having a resin content of 30% to 65% by weight, and the aqueous adhesive formulation has an aqueous phase of 12% to 25% by weight of a urea resin crosslinker which is a reaction product made from urea and a polyfunctional aldehyde and has a resin content of 30% to 65% by weight; and the water-based adhesive formulation has a p Ka 0.1% to 4% by weight of an acid catalyst having a value of 1. A chemically curable water-based adhesive formulation comprising: [Aspect 2] The hydroxy R of a reactive resin functionalized with a hydroxyl group, R 2. The adhesive formulation according to claim 1, wherein the mixture of reactive resins functionalized with groups has an active hydrogen equivalent of the aqueous phase of 200 g / mol to 1500 g / mol. [Aspect 3] The hydroxy R A reactive resin functionalized with a hydroxyl group or R 3. The adhesive formulation according to aspect 1 or 2, characterized in that the mixture of reactive resins functionalized with groups is selected from the group consisting of acrylate resins, functionalized styrene acrylate resins, functionalized acrylic acid copolymers, functionalized acrylate-urethane copolymers and functionalized (meth)acrylate copolymers. [Aspect 4] 4. The adhesive formulation according to any one of the preceding claims, comprising 0.1% to 20% by weight of the polyhydric alcohol or polyhydric alcohols. [Aspect 5] 5. The adhesive formulation according to any one of the preceding aspects, comprising 0.1% to 5% by weight of an anionic wax or a neutral wax or a mixture of these waxes. [Aspect 6] 6. The adhesive formulation according to any one of the preceding aspects, comprising 0.1% to 35% by weight of one or more fillers and / or pigments. [Aspect 7] 6. The adhesive formulation according to any one of the preceding claims, comprising 0.1 wt.% to 6 wt.% of one or more wetting agents. [Aspect 8] 8. The adhesive formulation according to any one of the preceding aspects, comprising 0.1 wt.% to 8 wt.% of one or more antifoaming agents. [Aspect 9] 9. The adhesive formulation according to any one of the preceding aspects, comprising 0.1 wt.% to 8 wt.% of one or more thickeners. [Aspect 10] Hydroxy R of reactive resins functionalized with groups, or hydroxy R a first aqueous component A with an aqueous phase of the mixture consisting of a reactive resin functionalized with a group, and a second component B comprising an aqueous phase of a urea resin crosslinker; The components A and B are provided to form an adhesive formulation by mixing the components A and B; The adhesive formulation comprises 60% to 90% by weight of component A and 10% to 40% by weight of component B. 10. The adhesive formulation according to any one of the preceding claims, characterized in that [Aspect 11] 1. A method for producing a pressed material body, in particular a pressed material plate, comprising the steps of: - providing a chip material and / or a fibre material or a chip material and / or a fibre material mixture, - providing a chemically curable adhesive formulation; - mixing chip material and / or fiber material or a chip material and / or fiber material mixture with said adhesive formulation to produce a press cake; - compressing the press cake continuously while the adhesive formulation is curing, or compressing press cake pieces discontinuously in a press mould while producing press cake pieces and curing the adhesive formulation; 20. The method of claim 19, further comprising: As the adhesive formulation, the chemically curable water-based adhesive formulation according to any one of the first to tenth aspects is used, The presscake or the presscake pieces have a weight percentage of chip material and / or fiber material or chip material and / or fiber material mixture of 77% to 98.5% by weight and a weight percentage of an adhesive composition of 1% to 20% by weight. A method comprising: [Aspect 12] The method of claim 11, wherein in the process of mixing the chip material and / or fiber material or the chip material and / or fiber material mixture with the adhesive formulation, 0.1% by weight to 5% by weight of a solid wax is mixed. [Aspect 13] 1. A method of manufacturing a press material plate, comprising: - providing a number of plates with chip material and / or fiber material; - coating at least one side of the plate intended for bonding to another plate with an adhesive compound; - stacking the coated plates to form a plate stack; - compressing the plate stack in a press mould whilst the adhesive formulation is curing; 20. The method of claim 19, further comprising: As the adhesive formulation, a chemically curable water-based two-part adhesive formulation according to any one of the first to twelfth aspects is used, The weight percentage of the plates in the plate stack is between 80% and 99% by weight, and the weight percentage of the adhesive formulation in the plate stack is between 1% and 20% by weight. A method comprising: [Explanation of symbols]

[0091] 1. Press Cake 2. Double Belt Press 3 Underbelt 4 Overbelt 5 Heating means 6 Press material strands 7 Plate stack 8 Plate 9. Adhesive Compounds 10 Press Stamp

Claims

1. A chemically curable, aqueous adhesive formulation for producing pressed material bodies by continuous or discontinuous compression of a mixture of the adhesive formulation and chips and / or fiber material or by compression of a laminate of the adhesive formulation and chip and / or fiber material plates, the water-based adhesive formulation is a chemically curable water-based two-part adhesive formulation comprising at least one chemically curable reactive resin and at least one crosslinker for the reactive resin; the aqueous adhesive formulation has an aqueous phase of 35% to 85% by weight of a hydroxyl functionalized reactive resin or a mixture of hydroxyl functionalized reactive resins, the aqueous phase having a resin content of 30% to 65% by weight, and the water-based adhesive formulation has an aqueous phase of 12% to 25% by weight of a urea resin crosslinker having a resin content of 30% to 65% by weight. In things, The urea resin crosslinking agent is a reaction product made from urea and a polyfunctional aldehyde, and the aqueous adhesive formulation has 0.1% to 4% by weight of an acid catalyst having a pKa value of 2 or less; the active hydroxyl equivalent weight of the hydroxyl-functionalized reactive resin or of the mixture of hydroxyl-functionalized reactive resins is from 200 g / mol to 1500 g / mol; the reactive resin functionalized by hydroxyl groups or the mixture of reactive resins functionalized by hydroxyl groups is selected from the group consisting of acrylate resins, functionalized styrene acrylate resins, functionalized acrylic acid copolymers, functionalized acrylate-urethane copolymers and functionalized (meth)acrylate copolymers, 1. A chemically curable water-based adhesive formulation comprising:

2. 10. The adhesive formulation of claim 1 having from 0.1% to 20% by weight of a polyhydric alcohol or polyhydric alcohols.

3. 3. An adhesive formulation according to claim 1 or 2, characterized in that it comprises from 0.1% to 5% by weight of anionic wax or neutral wax or a mixture of these waxes.

4. 4. The adhesive formulation according to any one of claims 1 to 3, characterized in that it comprises from 0.1% to 35% by weight of one or more fillers and / or pigments.

5. 5. An adhesive formulation according to any one of the preceding claims, characterized in that it comprises from 0.1% to 6% by weight of one or more wetting agents.

6. 6. An adhesive formulation according to any one of the preceding claims, characterized in that it comprises from 0.1% to 8% by weight of one or more defoamers.

7. 7. An adhesive formulation according to any one of the preceding claims, characterized in that it comprises from 0.1% to 8% by weight of one or more thickeners.

8. a first aqueous component A with an aqueous phase of a hydroxyl-functionalized reactive resin or of a mixture of hydroxyl-functionalized reactive resins, and a second component B comprising an aqueous phase of a urea resin crosslinker; The components A and B are provided to form an adhesive formulation by mixing the components A and B; The adhesive formulation comprises 60% to 90% by weight of component A and 10% to 40% by weight of component B.

8. The adhesive formulation according to any one of claims 1 to 7.

9. 1. A method for producing a pressed material body, comprising: - providing a chip material and / or a fibre material or a chip material and / or fibre material mixture, - providing a chemically curable adhesive formulation; - mixing chip material and / or fiber material or a chip material and / or fiber material mixture with said adhesive formulation to produce a press cake; - compressing the press cake continuously while the adhesive formulation is curing, or compressing the press cake pieces discontinuously in a press mould while producing press cake pieces and curing the adhesive formulation; 20. The method of claim 19, further comprising: The adhesive formulation is a chemically curable, water-based, two-part adhesive formulation having at least one chemically curable reactive resin and at least one crosslinker for the reactive resin; The water-based adhesive formulation has an aqueous phase of 35% to 85% by weight of a hydroxyl-functionalized reactive resin or a mixture of hydroxyl-functionalized reactive resins, the aqueous phase having a resin content of 30% to 65% by weight, The water-based adhesive formulation has an aqueous phase of 12% to 25% by weight of a urea resin crosslinker that is a reaction product formed from urea and a polyfunctional aldehyde, and has a resin content of 30% to 65% by weight; the water-based adhesive formulation has 0.1% to 4% by weight of an acid catalyst having a pKa value of 2 or less; the presscake or the presscake pieces having a weight percentage of chip material and / or fiber material or chip material and / or fiber material mixture of 77% to 98.5% by weight and a weight percentage of the adhesive formulation of 1% to 20% by weight, the reactive resin functionalized by hydroxyl groups or the mixture of reactive resins functionalized by hydroxyl groups is selected from the group consisting of acrylate resins, functionalized styrene acrylate resins, functionalized acrylic acid copolymers, functionalized acrylate-urethane copolymers and functionalized (meth)acrylate copolymers, A method comprising:

10. 10. The method according to claim 9, characterized in that in the process of mixing the chip material and / or fiber material or the chip material and / or fiber material mixture with the adhesive formulation, 0.1% by weight to 5% by weight of solid wax is mixed.

11. 1. A method for producing a press material plate, comprising: - providing a number of plates with chip material and / or fiber material; - coating at least one side of the plate intended for bonding to another plate with an adhesive compound; - stacking the coated plates to form a plate stack; - compressing the plate stack in a press whilst the adhesive formulation is curing; 20. The method of claim 19, further comprising: As the adhesive formulation, a chemically curable water-based two-part adhesive formulation is used having at least one chemically curable reactive resin and at least one crosslinker for said reactive resin, The water-based adhesive formulation has an aqueous phase of 35% to 85% by weight of a hydroxyl-functionalized reactive resin or a mixture of hydroxyl-functionalized reactive resins, the aqueous phase having a resin content of 30% to 65% by weight, The water-based adhesive formulation has an aqueous phase of 12% to 25% by weight of a urea resin crosslinker that is a reaction product formed from urea and a polyfunctional aldehyde, and has a resin content of 30% to 65% by weight; the water-based adhesive formulation has 0.1% to 4% by weight of an acid catalyst having a pKa value of 2 or less; The weight percentage of the plates in the plate stack is between 80% and 99% by weight, and the weight percentage of the adhesive formulation in the plate stack is between 1% and 20% by weight, the reactive resin functionalized by hydroxyl groups or the mixture of reactive resins functionalized by hydroxyl groups is selected from the group consisting of acrylate resins, functionalized styrene acrylate resins, functionalized acrylic acid copolymers, functionalized acrylate-urethane copolymers and functionalized (meth)acrylate copolymers, A method comprising:

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