DISPERSION ADHESIVES

Description

[0001] The invention relates to the use of aqueous dispersion adhesives based on a mixture of aqueous polyurethane or polyurethane-urea dispersions for the bonding of foam substrates by the spray coagulation process.

[0002] When bonding foam substrates to other substrates, for example, in foam-to-foam, foam-to-wood, and foam-to-plastic combinations, polychloroprene dispersion adhesives are predominantly used using the spray coagulation process. In this process, the adhesive and a coagulant are separately pumped into a spray gun, mixed in the spray jet, and coagulated. Since the mixing only occurs in the spray jet, no pot life is required. Furthermore, the coagulated adhesive remains on the substrate surface to be bonded and does not diffuse, or only slightly, into the pore structure of the foam substrates. High initial strengths, sufficiently long open times, and good heat resistance are often achieved.

[0003] Important areas of application include the manufacture of mattresses and seating furniture. Demand for chlorine-free alternatives to polychloroprene dispersion adhesives is particularly strong in Scandinavian countries, in order to meet the requirements of the Nordic Ecolabel (Type I environmental label according to ISO 14024), for example. They should also be characterized by high initial strength and a sufficiently long open time.

[0004] Adhesives based on aqueous polyurethane dispersions have established themselves worldwide in demanding industrial applications, for example in shoe manufacturing, the bonding of parts for automotive interiors, film lamination or the bonding of textile substrates.

[0005] When using such dispersions to bond substrates, the thermal activation process is often used. In this process, the dispersion is applied to the substrate, and after the water has completely evaporated, the adhesive layer is activated by heating, e.g., with an infrared radiator, and converted into an adhesive state. The temperature at which the adhesive film becomes tacky is referred to as the activation temperature.

[0006] When using polyurethane or polyurethane-polyurea dispersions, the wet bonding process can also be used, meaning the bonding is carried out immediately after the adhesive is applied. Mechanical fixation of the parts to be joined is required until the adhesive sets. This process is often used for bonding wood or textile substrates.

[0007] Both the thermal activation process and the wet bonding process are unsuitable for bonding foam substrates. In particular, the slow evaporation of water requires long waiting times between adhesive application and the bonding process, or appropriate drying equipment. Furthermore, a significant portion of the adhesive can diffuse into the pores of the foam substrates before or during drying, making it unavailable for the actual bonding process.

[0008] The adhesives based on aqueous polyurethane dispersions established on the market are generally unsuitable for spray coagulation because they either do not coagulate quickly enough, lack sufficient initial strength, or, due to the crystallinity of the polymers, form very hard bond lines, which are particularly unacceptable in mattress manufacturing. Furthermore, the open time—that is, the time between application of the adhesive and joining of the parts during which a sufficiently strong bond is still achieved—is usually only one minute. However, many bonding processes require at least twice that time.

[0009] WO 2013 / 053786 A1 describes aqueous polyurethane dispersions whose polymer has a melting temperature in the range of 30 °C to 50 °C, determined by dynamic differential thermal analysis according to DIN 65467 at a heating rate of 20 K / min. The polymer is obtainable from two differently crystallizing polyester polyols in specified proportions. These polyurethane dispersions are primarily suitable as cold contact adhesives, but can also be used by spray coagulation processes. However, the achievable initial strengths are insufficient for most foam bonding applications.

[0010] Luphen®< D DS 3548 from BASF AG (Ludwigshafen, Germany) is an epoxy resin-modified polyurethane dispersion that is said to be suitable for, among other things, the spray coagulation process. The epoxy resin used is based on bisphenol A diglycidyl ether. Since bisphenol A and its derivatives are viewed with extreme skepticism, particularly by end consumers, regarding their potential endocrine disruption and are therefore generally rejected, the market is demanding adhesives and other products that are free of bisphenol A.

[0011] WO 2014 / 182170 A1 describes the spray coagulation process using a special airless spray method. Mixtures of polychloroprene dispersions and tackifier dispersions, as well as polyurethane dispersions and tackifier dispersions, are used for this purpose. These are not further specified in this document, however. Areas of application mentioned include foam bonding in mattress and furniture manufacturing. However, this prior art does not disclose the type of polyurethane dispersions used, nor does it specify which measures can be taken to ensure high initial strength and a sufficiently long open time.

[0012] DE69604664 T2 discloses water-based adhesive formulations.

[0013] The object of the present invention was therefore to provide a chlorine- and bisphenol A-free alternative to polychloroprene dispersion adhesives for bonding foam substrates by the spray coagulation process, which does not have the disadvantages of the prior art and which is characterized by high initial strengths and a sufficiently long open time of at least 2 minutes.

[0014] From EP 2 090 603 A2 aqueous dispersions are known containing a mixture of A) an aqueous polyurethane or polyurethane-urea dispersion containing I. a polymer A) composed of I(i). at least one difunctional aliphatic polyester polyol having a molecular weight of 400 to 5000 g / mol, I(ii). at least one mixture of hexamethylene diisocyanate (HDI) and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) and I(iii). at least one mixture of two or more amine chain extenders, where at least one compound carries an ionic group, and the polymer A) is semi-crystalline after drying or crystalline with a glass transition temperature Tg between -65 °C and -40 °C, B) containing an aqueous polyurethane or polyurethane-urea dispersion different from A), II. a polymer B) composed of II(i). at least one difunctional aromatic polyester polyol having a molecular weight of 400 to 5000 g / mol, II(ii).at least one difunctional polyol component having a molecular weight of 62 to 399, II(iii) at least one aliphatic diisocyanate, and II(iv) at least one amine chain extender having an ionic group, wherein the polymer B) is amorphous after drying, with a glass transition temperature Tg between -15°C and +10°C.

[0015] According to EP 2 090 603 A2, the described mixtures of aqueous polyurethane or polyurethane-polyurea dispersions are suitable as adhesives both by the thermal activation process and by the wet bonding process and show bond strengths that are better than those of the individual components.

[0016] Surprisingly, it has now been found that the mixtures of aqueous polyurethane or polyurethane-polyurea dispersions described in EP 2 090 603 A2 are also outstandingly suitable for bonding foam substrates by the spray coagulation process, provided that defined proportions are maintained: The present invention thus relates to the use of aqueous dispersions containing a mixture of A) an aqueous polyurethane or polyurethane-urea dispersion containing I. a polymer A) composed of I(i). at least one difunctional aliphatic polyester polyol having a molecular weight of 400 to 5000 g / mol, I(ii). at least one mixture of hexamethylene diisocyanate (HDI) and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) and I(iii). at least one mixture of two or more amine chain extenders, where at least one compound carries an ionic group, and the polymer A) is semicrystalline after drying or crystalline with a glass transition temperature Tg between -65 °C and -40 °C and B) containing an aqueous polyurethane or polyurethane-urea dispersion different from A), II. a polymer B) composed of II(i). at least one difunctional aromatic polyester polyol having a molecular weight of 400 to 5000 g / mol, II(ii).at least one difunctional polyol component having a molecular weight of 62 to 399, II(iii). at least one aliphatic diisocyanate, and II(iv). at least one amine chain extender having an ionic group, wherein the polymer B) is amorphous after drying, with a glass transition temperature Tg between -15 °C and +10 °C; . and wherein the mixture contains 34.8 to 90.2 wt.% of polymer A) and 9.8 to 65.2 wt.% of polymer B), for the bonding of foam substrates by the spray coagulation process, wherein the glass transition temperature Tg is determined by DSC as defined in the description.

[0017] The dispersions referred to as polyurethane dispersions in the context of the present invention contain polymers as the disperse phase. These polymers may be polyurethanes in the narrower sense, i.e., polymers obtained by polymerizing polyols and polyisocyanates, but they may also be polymers in which mono- and / or diamines are used as structural components, optionally as chain extenders. Thus, the dispersions usable according to the invention are referred to as aqueous polyurethane or polyurethane-urea dispersions.

[0018] In the spray coagulation process, the aqueous adhesive dispersions and a coagulant are separately pumped into a 2-component spray gun and mixed in the spray jet. Typically, atomizing air is used for spraying at a pressure of 0.1 - 5 bar; however, at least one of the two components can also be delivered airless, as described, for example, in WO 2015 / 137808. The dispersion coagulates in the spray jet on its way to the surface of the first substrate; in the process, some of the water contained in the adhesive dispersion evaporates. Upon impact, the adhesive polymer forms a film on the surface of the first substrate which, while still wet, is immediately tacky. Since the mixing of adhesive dispersion and coagulant only takes place in the spray jet, no pot life needs to be observed.Due to the tackiness of the polymer film when wet, the second surface can be joined immediately, ideally, for example, by applying pressure to the substrates against the bonding surface. Applying pressure by pressing the two substrate surfaces together is advantageous because it increases the strength of the bond. It is also advantageous if at least one of the two substrates is porous or permeable to water to allow water to be removed from the solidifying adhesive joint.

[0019] Suitable coagulants are aqueous solutions of salts, preferably of metals from the first, second, and third main groups of the Periodic Table, especially if they exhibit good water solubility. Salts based on divalent or trivalent cations are preferred. Particular preference is given to using calcium chloride, zinc sulfate, or aluminum sulfate. Calcium chloride is most preferred. Mixtures of various salts as described above can also be used as aqueous solutions.

[0020] The concentration of the salts in the aqueous salt solutions suitable as coagulants is 1 to 20% by weight, preferably 2 to 10% by weight, and particularly preferably 3 to 4% by weight. The proportion of the aqueous solution of the coagulant, based on the total of adhesive solution plus coagulant solution, is between 0.1 and 50% by weight, preferably between 1 and 30% by weight, particularly preferably between 8 and 20% by weight, and most preferably between 12 and 18% by weight.

[0021] Alternatively, aqueous solutions of inorganic or organic acids, preferably citric acid, phosphoric acid or carbonic acid, as well as mixtures of one or more of the above-mentioned salts with one or more of these acids can be used as coagulants.

[0022] The dispersions used according to the invention each generally contain 30 to 55% by weight of solids, preferably 38 to 52% by weight. Based on the polymers A) and B) present as the disperse phase in the dispersions, the mixtures according to the invention contain 34.8 to 90.2% by weight of polymer A) and 9.8 to 65.2% by weight of polymer B), preferably 44.4 to 87.8% by weight of polymer A) and 12.2 to 55.6% by weight of polymer B), particularly preferably 54.5 to 81.9% by weight of polymer A) and 18.1 to 45.5% by weight of polymer B), and very particularly preferably 65.1 to 81.9% by weight of polymer A) and 18.1 to 34.9% by weight of polymer B), based on the total weight of the polymeric solids A) and B).

[0023] Suitable difunctional aliphatic polyester polyols A) I(i). Particularly suitable are linear polyesterdiols, such as those prepared in a known manner from aliphatic or cycloaliphatic dicarboxylic acids, such as succinic, methylsuccinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, nonanedicarbonic, decanedicarbonic, tetrahydrophthalic, hexahydrophthalic, cyclohexanedicarbonic, maleic, fumaric, malonic or mixtures thereof with polyhydric alcohols, such as ethanediol, di-, tri-, tetraethylene glycol, 1,2-propanediol, di-, tri-, tetrapropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-dihydroxycyclohexane, 1,4-dimethylolcyclohexane, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol or mixtures thereof.Instead of the free polycarboxylic acid, the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof can also be used to produce the polyesters.

[0024] Preferred are difunctional aliphatic polyester polyols A) I(i) based on succinic acid, methylsuccinic acid, glutaric acid, adipic acid or maleic acid and 1,3-propanediol, 1,4-butanediol or 1,6-hexanediol.

[0025] Particularly preferred are difunctional aliphatic polyester polyols A) I(i) based on adipic acid and 1,4-butanediol or 1,6-hexanediol.

[0026] Particularly preferred are difunctional aliphatic polyester polyols A) I(i) based on adipic acid and 1,4-butanediol.

[0027] The molecular weight of the difunctional aliphatic polyester polyol A) I(i) is between 400 and 5000 g / mol, preferably between 1500 and 3000 g / mol, particularly preferably between 1900 and 2500 g / mol, most particularly preferably between 2100 and 2300 g / mol.

[0028] A mixture of hexamethylene diisocyanate (HDI) and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI) is used as isocyanate component A) I(ii). The HDI:IPDI molar ratio is preferably between 9:1 and 1:9, more preferably between 3:1 and 1:3, and most preferably 2:1.

[0029] Component A) I(iii) consists of a mixture of two or more amine chain extenders, at least one of which carries an ionic group. Chain extenders, as used herein, also include monoamines that lead to chain termination.

[0030] Examples of monoamines are aliphatic and / or alicyclic primary and / or secondary monoamines such as ethylamine, diethylamine, the isomeric propyl- and butylamines, higher linear aliphatic monoamines, and cycloaliphatic monoamines such as cyclohexylamine. Further examples are amino alcohols, i.e., compounds containing amino and hydroxyl groups in one molecule, such as ethanolamine, N-methylethanolamine, diethanolamine, or 2-propanolamine. Further examples are monoamino compounds that additionally contain sulfonic acid and / or carboxyl groups, such as taurine, glycine, or alanine.

[0031] Examples of diamino compounds include 1,2-ethanediamine, 1,6-hexamethylenediamine, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (isophoronediamine), piperazine, 1,4-diaminocyclohexane, and bis(4-aminocyclohexyl)methane. Other suitable compounds include adipic acid dihydrazide, hydrazine, and hydrazine hydrate. Polyamines such as diethylenetriamine can also be used as building blocks instead of diamino compounds.

[0032] Further examples are amino alcohols, i.e. compounds containing amino and hydroxyl groups in one molecule, such as 1,3-diamino-2-propanol, N-(2-hydroxyethyl)ethylenediamine or N,N-bis(2-hydroxyethyl)ethylenediamine.

[0033] Examples of diamino compounds with an ionic group, i.e., which also carry sulfonate and / or carboxylate groups, include the sodium or potassium salts of N-(2-aminoethyl)-2-aminoethanesulfonic acid / carboxylic acid, N-(3-aminopropyl)-2-aminoethanesulfonic acid / carboxylic acid, N-(3-aminopropyl)-3-aminopropanesulfonic acid / carboxylic acid, or N-(2-aminoethyl)-3-aminopropanesulfonic acid / carboxylic acid. The sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid is preferred.

[0034] Preferred components of the mixture A) I(iii) are diethanolamine, 1,2-ethanediamine, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (isophoronediamine), piperazine, N-(2-hydroxyethyl)ethylenediamine, and the sodium salts of N-(2-aminoethyl)-2-aminoethanesulfonic acid / carboxylic acid.

[0035] A mixture of diethanolamine and the sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid is particularly preferred.

[0036] After drying, the polymer A) is semi-crystalline or crystalline with a glass transition temperature Tg between -65 °C and -40 °C, preferably with a Tg between -60 °C and -45 °C, particularly preferably between -55 °C and -50 °C.

[0037] Polymer A) is referred to as semicrystalline or crystalline if, in the DSC measurement according to DIN 65467 at a heating rate of 20 K / min, it exhibits a melting peak corresponding to a melting enthalpy of > 5 J / g, preferably > 10 J / g, particularly preferably > 20 J / g, and most preferably > 40 J / g. The melting peak is caused by the melting of regular substructures in the polymer. The melting temperature is preferably in a range between 30 °C and 80 °C, particularly preferably between 40 °C and 70 °C, and most preferably between 42 °C and 55 °C. The first heating is evaluated to also detect slowly crystallizing polymers.

[0038] The polymer B) is referred to as amorphous if it has no melting peak on the first heating or only a melting peak with a melting enthalpy < 5 J / g, preferably < 3 J / g, particularly preferably < 1 J / g.

[0039] In a preferred embodiment of the invention, the amorphous polymer B) has no melting peak.

[0040] Suitable difunctional aromatic polyester polyols B) II(i). Particularly suitable are linear polyesterdiols, such as those which can be prepared in a known manner from aromatic dicarboxylic acids, such as terephthalic, isophthalic or o-phthalic acid and their acid anhydrides, such as o-phthalic anhydride, with polyhydric alcohols, such as ethanediol, di-, tri-, tetraethylene glycol, 1,2-propanediol, di-, tri-, tetrapropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-dihydroxycyclohexane, 1,4-dimethylolcyclohexane, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol or mixtures thereof.

[0041] Preferred are difunctional aromatic polyester polyols B) II(i) based on o-phthalic acid, o-phthalic anhydride, and 1,4-butanediol or 1,6-hexanediol.

[0042] Particularly preferred are difunctional aromatic polyester polyols B) II(i) based on o-phthalic acid or o-phthalic anhydride and 1,6-hexanediol.

[0043] The molecular weight of the difunctional aromatic polyester polyol B) II(i) is between 400 and 5000 g / mol, preferably between 1500 and 3000 g / mol, particularly preferably between 1800 and 2300 g / mol, and most preferably between 1900 and 2100 g / mol.

[0044] Suitable as component B) II(ii) are difunctional polyol components with a molecular weight of 62 to 399, for example, the products listed under A) I(i) and B) II(i), provided they have a molecular weight of 62 to 399 Daltons. Other suitable components are the polyhydric, particularly dihydric, alcohols mentioned for the production of polyester polyols, as well as low-molecular-weight polyester diols such as adipic acid bis(hydroxyethyl) ester. Short-chain difunctional polyether polyols, such as the homopolymers, copolymers, and graft polymers of ethylene oxide or propylene oxide, are also suitable.

[0045] Preferred synthesis components B) II(ii) are 1,4-butanediol and 1,6-hexanediol, particularly preferred is 1,6-hexanediol.

[0046] Any aliphatic compounds containing at least two free isocyanate groups per molecule are suitable as synthesis components B) II(iii). Preference is given to using diisocyanates Y(NCO) 2 , where Y represents a divalent aliphatic hydrocarbon radical having 4 to 12 carbon atoms or a divalent cycloaliphatic hydrocarbon radical having 6 to 15 carbon atoms. Examples of such preferred diisocyanates are tetramethylene diisocyanate, methylpentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 4,4'-diisocyanatodicyclohexylmethane or 4,4'-diisocyanatodicyclohexylpropane-(2,2) or mixtures thereof.

[0047] Particularly preferred are hexamethylene diisocyanate (HDI), 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 4,4'-diisocyanatodicyclohexylmethane, and mixtures thereof. However, the isocyanates are preferably used alone.

[0048] Hexamethylene diisocyanate (HDI) is particularly preferred.

[0049] Aminic chain extenders B) II(vi) with an ionic group are preferably diamino compounds that additionally carry sulfonate and / or carboxylate groups, such as, for example, the sodium or potassium salts of N-(2-aminoethyl)-2-aminoethanesulfonic acid, N-(3-aminopropyl)-2-aminoethanesulfonic acid, N-(3-aminopropyl)-3-aminopropanesulfonic acid, N-(2-aminoethyl)-3-aminopropanesulfonic acid, or the analogous carboxylic acids.

[0050] Particularly preferred are the sodium salts of N-(2-aminoethyl)-2-aminoethanesulfonic acid and the analogous carboxylic acid, most particularly preferred is the sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid.

[0051] The amine chain extenders B) II(iv) with an ionic group can be used alone or together with other amine chain extenders, such as those described under A) I(iii). They are preferably used alone.

[0052] The polymer B) is amorphous after drying with a glass transition temperature Tg between -15°C and +10°, preferably with a Tg between -10°C and +5°C, particularly preferably between -5°C and 0°C.

[0053] The aqueous polyurethane or polyurethane-urea dispersions containing the polymers A) or B) have a solids content of 10 to 70 wt.%, preferably of 25 to 60 wt.% and particularly preferably of 35 to 55 wt.%.

[0054] The aqueous polyurethane or polyurethane-urea dispersions containing polymers A) or B) are preferably prepared by the acetone process. For this purpose, prepolymers are prepared from components A) I(i) and A) I(ii) or B) II(i) and B) II(ii) and B II(iii) respectively, dissolved in acetone, and chain-extended with components A) I(iii) and B) II(iv) respectively. After dispersion with water, the acetone is distilled off. The application and implementation of the acetone process are state of the art and known to those skilled in the art.

[0055] The aqueous polyurethane or polyurethane-urea dispersions comprising the polymers A) or B) and the mixtures according to the invention preferably contain no external emulsifiers.

[0056] The dispersions according to the invention are preferably prepared by mixing the aqueous polyurethane or polyurethane or polyurethane-urea dispersions of the polymers A) or B).

[0057] The bonds produced using the dispersions according to the invention by the spray coagulation process show sufficient immediate strengths up to immediate material tear-out with an open time of at least 3 minutes. In particular, when bonding foam to foam or foam to other substrate surfaces such as wood, metal or plastic, which have a three-dimensional structure and are therefore not flat, the bonds produced by the process according to the invention are able to absorb the restoring forces of the foam without waiting time, in particular without completely removing the water. An example of such an application is the bonding of cuboid foam blocks to form pillows by folding the narrow side surfaces and immediately pressing them together while wet after spraying the adhesive dispersion according to the invention.Thanks to the high instant wet strength, the applied pressure can be released immediately without any springback or displacement of the stretched foam.

[0058] In particular, the dispersions of the invention are used to produce adhesive compositions suitable for producing adhesive composites, wherein the adhesive composite comprises a substrate, the dispersion of the invention, and another substrate. The two substrates can consist of the same or different materials. By definition, the substrates can also be sheet-like structures. Preferably, at least one substrate is a foam substrate.

[0059] A foam substrate is a substrate made of foam, with foams generally being synthetic materials with a cellular structure and low density. A distinction can be made between open-cell, closed-cell, and mixed-cell foams. Depending on their degree of hardness, foams are classified as rigid and flexible foams. Almost all plastics are suitable for foaming.

[0060] In principle, the dispersions according to the invention are suitable for bonding all foam substrates using the spray coagulation process. Open-cell and mixed-cell foam substrates are preferably bonded.

[0061] In a preferred embodiment of the invention, the foam substrate(s) consist of polyurethane (for example polyether and polyester foams) and / or a rubber such as natural rubber (NR), styrene-butadiene rubber (SBR), ethylene-propylene-diene polymer (EPDM), butadiene-acrylonitrile rubber (NBR) or chloroprene rubber (CR).

[0062] In a particularly preferred embodiment of the invention, the foam substrate(s) consist of polyurethane.

[0063] The dispersions of the invention are also characterized by good adhesion to a wide variety of other substrates, such as wood, paper, leather, textiles, cork, and plastics (thermoplastics, elastomers, thermosets, composites) such as various grades of polyvinyl chloride, polyurethanes, polyvinyl acetate, ABS, rubbers, polyethylvinyl acetate, polycarbonate, or polyolefins, such as filled or unfilled polypropylene. In rare cases, pretreatment of the substrate surface is necessary, for example, by priming, flame-treating, or corona treatment, particularly with nonpolar substrates.

[0064] The adhesive compositions containing the dispersions according to the invention are thus suitable for bonding any substrates, preferably made of the above-mentioned materials.

[0065] The adhesives according to the invention are particularly suitable for bonding foam to foam, foam to wood, foam to various plastics, as well as textiles to various substrates.

[0066] An adhesive composite comprising substrates and sheet materials bonded with the dispersions used according to the invention is also the subject of the present application, as are adhesive-bonded foam substrates obtained by the use according to the invention. Examples

[0067] The invention is explained in more detail below using examples. The following methods and test methods were used: A) Spray coagulation process:

[0068] It is applied using a standard spray gun for two-component dispersion adhesives, the PILOT III 2K from Walther Pilot. The adhesive and the coagulant CaCl2 (3 wt.% solution in water) are pumped separately into the spray gun, mixed in the spray jet, and the adhesive coagulates. Since mixing only occurs in the spray jet, no pot life is required. The ratio chosen was 86 wt.% adhesive dispersion and 14 wt.% CaCl2 solution.

[0069] The exact settings of the spray gun are generally known to the expert and can be tailored to the specific case without undue effort and determined through simple preliminary tests. The proportions and application weight can be determined by weighing the feed containers and the substrates.

[0070] The following settings were used: a.) Adhesive component: Feed pressure 1.3 bar b.) Coagulation component: Feed pressure 0.3 bar c.) Atomizing air pressure: 2.8 bar d.) Bore (nozzle) for adhesive component: 1.0 mm e.) Bore (nozzle) for coagulant component: 0.4 mm f.) Coating weights: 130 - 150 g / m 2 (wet) B) Determination of initial strength:

[0071] The test material used is (see Fig. 1) PU foam test specimen ST 5540 (1) from STN Schaumstoff-Technik-Nürnberg GmbH with the dimensions 10 x 5 x 3 cm and a density of 40 kg / m 3< were used. To assess the initial strength, the test specimens are bent in the middle (4) with a wooden rod (3) (round wood D = 7 mm or square 7 x 7 mm)) immediately after the adhesive has been applied to the upper side (2) of the foam bodies (1) using the spray coagulation process (application rate 130 - 150 g / m 2< wet) and then guided by means of the testing device (5) through two steel rollers (6) (diameter 40 mm, length 64 mm), the tangential distance (7) of which was previously set to 10 mm using a threaded spindle (8). The initial strength is sufficient if the test specimen or the adhesive seam (9) does not open despite the restoring forces present in the test specimen. C) Determination of the open time

[0072] The test material used is Recticel T 20120 polyether foam from Recticel, measuring 10 x 5 x 3 cm and with a density of 20 kg / m³. To assess the open time, the test specimens are bent in the middle and joined using light palm pressure immediately after adhesive application, every 60 seconds, or as needed at defined intervals using the spray coagulation method (application rate 130-150 g / m² wet). The end of the open time is indicated by the test specimen's insufficient strength and its opening due to the resulting restoring forces. D) Determination of the hardness of the adhesive seam:

[0073] The bonded seam of the test specimens produced under B) was assessed sensorially by touch after 24 hours of storage at room temperature in direct comparison to reference samples. The reference samples were produced using commercially available polychloroprene latices (Covestro Deutschland AG) of different Shore A hardness. The bonded seam of the test specimen made of Dispercoll®< C 84 (Shore A hardness of the pure, dried polymer = 88) was taken as the reference for a hard bonded seam, the bonded seam of the test specimen made of Dispercoll®< C 74 (Shore A hardness of the pure, dried polymer = 55) was taken as the reference for a medium-hard bonded seam, and the bonded seam of the test specimen made of Dispercoll®< C 2372 (Shore A hardness of the pure, dried polymer = 40) was taken as the reference for a soft bonded seam. E) Determination of glass transition temperatures, melting temperatures and enthalpies of fusion using DSC:

[0074] The glass transition temperatures, melting temperatures, and enthalpies of fusion were determined by differential scanning calorimetry (DSC) using a Pyris Diamond DSC calorimeter from Perkin-Elmer. A film was prepared by doctor blade coating the dispersion with a wet film thickness of 100 µm onto a glass plate, allowed to dry for 2 hours, and then dried together with the glass plate in a drying box for 3 days at room temperature and 0% relative humidity. The DSC curve was then recorded using 10 mg of sample material from this film under the following measurement conditions: rapid cooling to the starting temperature of -100 °C, followed by three heating cycles from -100 °C to +150 °C at a heating rate of 20 K / min and a cooling rate of 320 K / min under a helium atmosphere, followed by cooling with liquid nitrogen. The glass transition temperature corresponds to the temperature at half the glass transition, with the third heating cycle being evaluated.To determine the melting temperatures and enthalpies of fusion, the first heating was evaluated. F) Input materials:

[0075] Polyester I: Polyesterdiol from 1,4-butanediol and adipic acid with OH-Z = 50 Polyester II: Polyesterdiol from 1,6-hexanediol and phthalic anhydride with OH-Z = 56 Desmodur ®< H: Hexamethylene diisocyanate-1,6 (Covestro Deutschland AG, Leverkusen / D) Desmodur ®< I: Isophorone diisocyanate (Covestro Deutschland AG, Leverkusen / D) Example 1 (according to the invention):

[0076] Preparation of an aqueous polyurethane or polyurethane-urea dispersion containing polymer A): 450 g of polyester I are dewatered for 1 hour at 110°C and 15 mbar. At 80°C, 30.11 g of Desmodur ®< H and then 20.14 g of Desmodur ®< I are added. The mixture is stirred at 80 to 90°C until a constant isocyanate content of 1.15% is reached. The reaction mixture is dissolved in 750 g of acetone and cooled to 48°C. A solution of 5.95 g of the sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid and 2.57 g of diethanolamine in 65 g of water is added to the homogeneous solution with vigorous stirring. After 30 minutes, the mixture is dispersed by adding 700 g of water. After distillative separation of the acetone, an aqueous polyurethane-polyurea dispersion with a solids content of 40.0 wt.% is obtained.

[0077] After drying, the polymer contained is semi-crystalline with a glass transition temperature Tg of -54°C, a melting temperature of 48°C and a melting enthalpy of 50.4 J / g. Example 2 (according to the invention):

[0078] Preparation of an aqueous polyurethane or polyurethane-urea dispersion containing polymer B): 1215 g of polyester II are dewatered for 1 hour at 110°C and 15 mbar. At 80°C, 4.6 g of 1,6-hexanediol and 179.0 g of Desmodur ®< H are added, and the mixture is stirred at 90°C until a constant isocyanate content of 2.28% is reached. The reaction mixture is dissolved in 2490 g of acetone and cooled to 48°C. A solution of 31.9 g of the sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid in 300 g of water is added to the homogeneous solution with vigorous stirring. After 30 minutes, the mixture is dispersed by adding 1150 g of water. After distillative separation of the acetone, an aqueous polyurethane-polyurea dispersion with a solids content of 50.0 wt.% is obtained.

[0079] The polymer contained is amorphous after drying (without melting peak in DSC) and with a glass transition temperature Tg of -1.5°C. Example 3 (comparison):

[0080] Using the dispersion from Example 1 (containing 100% Polymer A). As can be seen from the table, the initial strength is good, but the bond line is too hard, and the open time of one minute is insufficient. Example 4 (comparison):

[0081] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 95 parts by weight of the dispersion from Example 1 (semi-crystalline) and 5 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 93.8 wt.% polymer A and 6.2 wt.% polymer B.

[0082] As can be seen from the table, the initial strength is good, but the bonded seam is too hard and the open time of one minute is not sufficient. Example 5 (according to the invention):

[0083] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 92 parts by weight of the dispersion from Example 1 (semi-crystalline) and 8 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 90.2 wt.% polymer A and 9.8 wt.% polymer B.

[0084] As can be seen from the table, the initial strength is good, the bond line is medium hard and the open time of three minutes meets the requirements. Example 6 (according to the invention):

[0085] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 90 parts by weight of the dispersion from Example 1 (semi-crystalline) and 10 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 87.8 wt.% polymer A and 12.2 wt.% polymer B.

[0086] As can be seen from the table, the initial strength is good, the bond line is medium hard and the open time of four minutes meets the requirements. Example 7 (according to the invention):

[0087] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 85 parts by weight of the dispersion from Example 1 (semi-crystalline) and 15 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 81.9 wt.% polymer A and 18.1 wt.% polymer B.

[0088] As can be seen from the table, the initial strength is good, the bond line is medium hard and the open time of 7 minutes meets the requirements. Example 8 (according to the invention):

[0089] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 80 parts by weight of the dispersion from Example 1 (semi-crystalline) and 20 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 76.2 wt.% polymer A and 23.8 wt.% polymer B.

[0090] As can be seen from the table, the initial strength is good, the bond line is medium hard and the open time of 7 minutes meets the requirements. Examples 9 (according to the invention):

[0091] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 75 parts by weight of the dispersion from Example 1 (semi-crystalline) and 25 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 70.6 wt.% polymer A and 29.4 wt.% polymer B.

[0092] As can be seen from the table, the initial strength is good, the bond line is medium hard and the open time of 7 minutes meets the requirements. Examples 10 (according to the invention):

[0093] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 70 parts by weight of the dispersion from Example 1 (semi-crystalline) and 30 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 65.1 wt.% polymer A and 34.9 wt.% polymer B.

[0094] As can be seen from the table, the initial strength is good, the bond line is medium hard and the open time of 7 minutes meets the requirements. Example 11 (according to the invention):

[0095] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 60 parts by weight of the dispersion from Example 1 (semi-crystalline) and 40 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 54.5 wt.% polymer A and 45.5 wt.% polymer B.

[0096] As can be seen from the table, the initial strength is good, the bond line is medium hard and the open time of 7 minutes meets the requirements. Example 12 (according to the invention):

[0097] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 50 parts by weight of the dispersion from Example 1 (semi-crystalline) and 50 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 44.4 wt.% polymer A and 55.6 wt.% polymer B.

[0098] As can be seen from the table, the initial strength is good, the bond line is medium hard and the open time of 4 minutes meets the requirements. Example 13 (according to the invention):

[0099] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 40 parts by weight of the dispersion from Example 1 (semi-crystalline) and 60 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 34.8 wt.% polymer A and 65.2 wt.% polymer B.

[0100] As can be seen from the table, the initial strength is good, the bond line is soft and the open time of 3 minutes meets the requirements. Example 14 (comparison):

[0101] Preparation of an inventive mixture from the dispersions of Examples 1 and 2 and use: 30 parts by weight of the dispersion from Example 1 (semi-crystalline) and 70 parts by weight of the dispersion from Example 2 (amorphous) are mixed with stirring and homogenized. Taking the solids content into account, the inventive mixture contains 25.5 wt.% polymer A and 74.5 wt.% polymer B.

[0102] As can be seen from the table, there is no initial strength. Example 15 (comparison):

[0103] Use of the dispersion from Example 2 (containing 100% Polymer B)

[0104] As can be seen from the table below, there is no initial strength. Table: Results of the inventive tests and the comparative tests Example Polymer A / B [wt.%] Initial strength Hardness of the seam Open time [minutes] 3 (Comparison) 100 / 0 Yes hard 1 4 (Comparison) 93,8 / 6,2 Yes hard 1 5 (according to the invention) 90,2 / 9,8 Yes medium 3 6 (according to the invention) 87,8 / 12,2 Yes medium 4 7 (according to the invention) 81,9 / 18,1 Yes medium 7 8 (according to the invention) 76,2 / 23,8 Yes medium 7 9 (according to the invention) 70,6 / 29,4 Yes medium 7 10 (according to the invention) 65,1 / 34,9 Yes medium 7 11 (according to the invention) 54,5 / 45,5 Yes medium 6 12 (according to the invention) 44,4 / 55,6 Yes medium 4 13 (according to the invention) 34,8 / 65,2 Yes soft 3 14 (Comparison) 25,5 / 74,5 no not determinable 0 15 (Comparison) 0 / 100 no not determinable 0

Claims

1. Use of an aqueous dispersion containing a mixture of A) an aqueous polyurethane or polyurethane-urea dispersion containing I. a polymer A) formed from I (i). at least one difunctional aliphatic polyester polyol having a molecular weight of 400 to 5000 g / mol, I (ii). at least one mixture of hexamethylene diisocyanate (HDI) and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), and I (iii). at least one mixture of two or more aminic chain extenders, wherein at least one compound bears an ionic group, and the polymer A) after drying is semicrystalline or crystalline with a glass transition at a glass transition temperature Tg of between -65°C and -40°C, and B) an aqueous polyurethane or polyurethane-urea dispersion which differs from A) and contains II. a polymer B) formed from II (i). at least one difunctional aromatic polyester polyol having a molecular weight of 400 to 5000 g / mol, II (ii). at least one difunctional polyol component having a molecular weight of 62 to 399, II (iii). at least one aliphatic diisocyanate and II (iv). at least one aminic chain extender having an ionic group, wherein the polymer B) after drying is amorphous with a glass transition at a glass transition temperature Tg of between -15°C and +10°C; and wherein the mixture contains 34.8% to 90.2% by weight of polymer A) and 9.8% to 65.2% by weight of polymer B), based on the sum total of polymers A) and B), for the adhesive bonding of foam substrates by the spray coagulation process, wherein the glass transition temperature Tg is determined by means of DSC as defined in the description.

2. Use of an aqueous dispersion according to Claim 1, characterized in that the mixture contains 44.4% to 87.8% by weight of polymer A) and 12.2% to 55.6% by weight of polymer B).

3. Use of an aqueous dispersion according to Claim 1, characterized in that the mixture contains 54.5% to 81.9% by weight of polymer A) and 18.1% to 45.5% by weight of polymer B).

4. Use of an aqueous dispersion according to any of Claims 1 to 3, characterized in that the HDI:IPDI molar ratio is between 9:1 and 1:9.

5. Use of an aqueous dispersion according to any of Claims 1 to 3, characterized in that the HDI:IPDI molar ratio is between 3:1 and 1:3.

6. Use of an aqueous dispersion according to any of Claims 1 to 5, characterized in that component A) I(iii). is a mixture of diethanolamine and the sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid.

7. Use of an aqueous dispersion according to any of Claims 1 to 6, characterized in that component B) II(i). is a polyester polyol based on o-phthalic acid, o-phthalic anhydride and butane-1,4-diol or hexane-1,6-diol.

8. Use of the aqueous dispersions according to any of Claims 1 to 7 for the production of adhesive compositions.

9. Adhesive-bonded foam substrates obtained by the use according to Claim 1.