WO2003000818A2

WO2003000818A2 - Multi-component adhesive

Info

Publication number: WO2003000818A2
Application number: PCT/EP2002/006421
Authority: WO
Inventors: Bernhard Grünewälder; Klaus Friedrich; Gerard Jakubowski; Christoph Lohr; Werner Haller; Roberto Antonio Pavez Aranguiz
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 2001-06-21
Filing date: 2002-06-12
Publication date: 2003-01-03
Also published as: BR0210939B1; BR0210939A; HK1065557A1; WO2003000818A3; EP1397457A2; CN1518584A; DE10225444A1; CN1247726C

Abstract

The invention relates to a multi-component adhesive that contains at least two components A and B, wherein a) component A contains at least one polymer dispersion, comprising water, at least one polymer producible by emulsion polymerization, at least one protective colloid, at least one water-soluble, acidic metal salt, and b) component B contains at least one cross-linking resin. The invention further relates to an adhesive kit that contains at least two of the above-mentioned components, and to the use of components A and B in multi-component adhesives.

Description

Multi-component adhesive

The present invention relates to a multicomponent adhesive with at least 2 components A and B, where a) component A comprises at least one polymer dispersion comprising water, at least one polymer which can be prepared by emulsion polymerization, at least one protective colloid, at least one water-soluble, acidic metal salt and b) component B at least one Contains crosslinking resin.

The use of adhesives in the manufacture of industrial goods is increasingly replacing mechanical fasteners. This happens particularly where the connection of two workpieces is only exposed to moderate mechanical loads. The advantages of using adhesives to bring about mechanical connections lie in particular in the simple application of the adhesives, the possibility of continuously and, if desired, operating the connection of materials over the entire surface and the high resilience of modern adhesives, such as those used in the furniture industry.

Dispersion adhesives are often used in this area, as can be obtained, for example, by emulsion polymerization of ethylenically unsaturated monomers in the aqueous phase. However, the disadvantage of such adhesives is the fact that, owing to the presence of emulsifiers and protective colloids in the aqueous dispersion, they often have only a low resistance to moisture or water. For example, GB-A 1,440,337 describes an adhesive which is said to have a long shelf life and to be resistant to moisture. The adhesive described contains a vinyl ester polymer, polyvinyl alcohol as a protective colloid, a water-soluble urea-formaldehyde resin with a lower degree of condensation and a water-soluble, acidic metal salt. From the examples disclosed in the document, however, it follows that the corresponding adhesive is not up to the requirements that arise in modern adhesive applications with regard to water resistance. In addition, no multi-component adhesives are described which have at least two separate components.

EP-B 0 686 682 relates to a dispersion adhesive based on polyvinyl ester, the films of which have increased water resistance. For this purpose, an aqueous polyvinyl ester dispersion is used which, in addition to polymeric protective colloids, contains water-soluble compounds and derivatives of polyaldehydes which can be complexed with the polymeric protective colloids and from which aldehyde groups can be released in a controlled manner in acidic media. However, multi-component adhesives are not described.

A disadvantage of the above-mentioned prior art is the fact that the adhesives described either do not meet the requirements with regard to water resistance or require low molecular weight polyaldehydes, either in free form or, for example, as a bisulfite adduct as crosslinking agents. The problem here is that the polyaldehydes mentioned or their adducts generally have a strong intrinsic odor, which may be perceived as disturbing or even harmful to health.

Polymer dispersions used in practice, which are used in the area of bonding wood and wood-based materials in industry and trade, but also in the do-it-yourself area (do-it-yourself area), are usually ready-made, one-component adhesives, which can essentially be found in their Differentiate water resistance. Such one-component adhesives ready for use by processors are stable in storage for different lengths of time, depending on their water resistance after setting. In principle, such adhesives decrease with increasing water resistance the storage stability. In practice, PVAc dispersions are usually used, which are classified in the water resistance class D2, measured according to DEN EN 204. Although these dispersions have good storage stability, they cannot be used in areas with frequent exposure to moisture. They are only suitable for indoor use with occasional brief exposure to cold water.

In addition, one-component dispersion adhesives are known from the prior art which meet the stress group D3 according to DIN EN 204. Although these dispersion adhesives have a higher water resistance, they only have a storage stability of only about 6 to 12 months at room temperature.

While such storage stability is often sufficient due to a regular and usually predictable throughput of adhesives in the industrial area, this does not apply to DIY products in the do-it-yourself area. In this case, only a small amount of adhesive is often initially required for bonding, the remaining adhesive residue should be storable and accessible for later use.

Another disadvantage of such adhesive systems is that they often discolor the wood to be bonded, triggered by their hardener content. Fashion woods such as American maple, birch, beech or cherry are particularly affected. The wood constituents react with the hardener system of the adhesive to form irreversible color complexes. Such discolouration will not be tolerated by the user.

In addition, there are also one-component dispersion adhesives that have high water resistance, but only have a storage stability of approx. 3 to 6 months at room temperature due to a very reactive hardener system. Such dispersions also frequently lead to discoloration of the aforementioned woods. Multicomponent polyisocyanate-based adhesives are also known from the prior art. Adhesives of this type generally have good water resistance, but are not free from disadvantages. Such adhesives often tend to foam when water enters the isocyanate component. In addition, the pot life and open time for such adhesives are often very short. In addition, the adhesives are generally expensive, since the moisture-sensitive isocyanate hardener requires complex packaging and often has to be filled under protective gas. Due to the isocyanate content, such adhesives are subject to labeling in many countries, which reduces consumer acceptance.

It was therefore an object to provide a dispersion adhesive which does not have the disadvantages of the adhesives known from the prior art. In particular, it was an object of the present invention to provide a multicomponent adhesive whose water resistance is increased by mixing at least one resin component and at least one hardener component compared to the water resistance of an adhesive bond carried out only with the resin component.

The task is solved by a multi-component adhesive comprising at least two components, as described in the context of the text below.

The invention therefore relates to a multicomponent adhesive with at least 2 components A and B, where a) component A at least one polymer dispersion comprising water, at least one polymer which can be prepared by emulsion polymerization, at least one protective colloid, at least one water-soluble, acidic metal salt and b) component B at least a crosslinking resin based on phenol-formaldehyde condensates, hydroxymethyl-substituted melamines, hydroxymethyl-substituted imidazolidinones or thioimidazolidinones, hydroxymethyl-substituted pyrimidinones or hydroxymethyl-substituted triazinones or their self-condensation products or mixed condensates of two or more of the compounds mentioned, or a mixture of two or more of the compounds mentioned.

In the context of the present invention, a multi-component adhesive is understood to mean an adhesive which comprises at least two components which are present separately from one another. The individual components of a multi-component adhesive are generally reactive with one another. To use a multi-component adhesive, the individual components are mixed with one another, resulting in the actual adhesive that develops the adhesive force.

A multi-component adhesive according to the present invention comprises at least 2 components A and B. However, it is also provided according to the invention that a multi-component adhesive according to the invention has more than 2 components, for example 3, 4 or more components. In the context of a preferred embodiment of the present invention, however, a multi-component adhesive according to the invention has two or three components, in particular two components.

A multicomponent adhesive according to the invention contains at least one component A, such a component A containing at least one polymer dispersion, at least one protective colloid, at least one water-soluble, acidic metal salt.

In the context of the present invention, a “polymer dispersion” is understood to mean a dispersion of particulate polymer particles in the aqueous phase. The size of the polymer particles is in a range that is usually observed when carrying out polymerizations by means of emulsion polymerization. Exemplary sizes within the scope of the present invention are in a range from about 0.001 to about 100 μm or about 0.05 to about 20 μm, preferably from about 0.01 to 5 μm, and in particular from about 0.01 to 2 μm.

The polymer dispersions which can be used according to the invention can contain water which comes from any source. For example, the water used in the polymer dispersions according to the invention is tap water, as it is is usually available from appropriate supply sources. However, it is equally possible to use groundwater, process water, process water or any other form of server recovered from a cycle in the polymer dispersions according to the invention, provided that the pH and the salt content allow stable polymer dispersions to be maintained.

For the preparation of the polymer dispersions according to the invention, olefinically unsaturated monomers are suitable which are accessible to emulsion polymerization. Suitable polymers for the preparation of the dispersions according to the invention are, for example, vinyl ester polymers, the monomeric basic unit of which is a vinyl ester of a linear or branched carboxylic acid having about 2 to about 44, for example about 3 to about 15, carbon atoms. The monomers for these homo- or copolymeric polyvinyl esters are vinyl formate, vinyl acetate, vinyl propionate, vinyl isobutyrate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl esters of saturated branched monocarboxylic acids with 9 to about 15 carbon atoms in the acid residue, vinyl esters of longer-chain saturated or unsaturated fatty acids Vinyl laurate, vinyl stearate or vinyl ester of benzoic acid and substituted derivatives of benzoic acid such as vinyl p-tert-butylbenzoate in question. The vinyl esters mentioned can each be present individually or as a mixture of two or more of the vinyl esters mentioned in the polyvinyl ester. In the context of a preferred embodiment of the invention, the proportion of such vinyl esters in the entire polymer is at least about 50% by weight, for example at least about 75% by weight.

In a further preferred embodiment of the present invention, polymers can also be present in the polymer dispersion which, in addition to one of the above-mentioned vinyl esters or a mixture of two or more of the above-mentioned vinyl esters, also have further comonomers. Further ethylenically unsaturated monomers which can be copolymerized with the abovementioned vinyl esters are, for example, acrylic acid, methacrylic acid and their esters with primary and secondary saturated monohydric alcohols having 1 to about 28 carbon atoms, such as methanol, ethanol, propanol, butanol, 2-ethylhexyl alcohol, cycloaliphatic Alcohols such as cyclohexanol, hydroxymethylcyclohexane or hydroxyethylcyclohexane. The esters of the above-mentioned, ethylenically unsaturated acids with longer-chain fatty alcohols are also suitable. Also suitable as comonomers are ethylenically unsaturated Dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid or citraconic acid and their mono- or diesters with saturated monohydric aliphatic alcohols with 1 to about 28 carbon atoms. The proportion of such comonomers in the polymers present in the polymer dispersion which can be used according to the invention can be up to about 25% by weight, for example about 0.1 to about 15% by weight.

Also suitable as comonomers are simple ethylenically unsaturated hydrocarbons such as ethylene or o-olefins having about 3 to about 28 carbon atoms, for example propylene, butylene, styrene, vinyltoluene, vinylxylene and halogenated unsaturated aliphatic hydrocarbons such as vinyl chloride, vinyl fluoride, vinylidene chloride, vinylidene fluoride and the like , Such comonomers can have a proportion of the polymer which can be used in the dispersions according to the invention of up to about 50% by weight or less, for example about 0.5 to about 25% by weight.

Multi-ethylenically unsaturated monomers, for example, can also be used as comonomers in the context of the present invention. Examples of such monomers are diallyl phthalates dimethacrylate 4-diallyl maleate, triallyl cyanurate, tetraallyloxyethane, divinylbenzene, butane-l, triethylene glycol dimethacrylate, divinyl adipate, allyl acrylate, allyl methacrylate, vinyl crotonate, methylenebisacrylamide, hexanediol diacrylate, pentaerythritol diacrylate or trimethylolpropane triacrylate or mixtures of two or more thereof. The proportion of such comonomers in the polymers prepared by emulsion polymerization in the polymer dispersions which can be used according to the invention is up to about 10% by weight, for example about 0.01 to about 5% by weight.

Also suitable as comonomers are ethylenically unsaturated compounds with N-functional groups. These include for example acrylamide, methacrylamide, allyl carbamate, acrylonitrile, N-methylolacrylamide, N-methylolmethacrylamide, N-methylolallyl carbamate and the N-methylol esters, alkyl ethers or Mannich bases of N-methylolacrylamide or N-methylolmethacrylamide or N-Methylolallylcarbamats, acrylamidoglycolic acid, Acrylamidomethoxyssigsäuremethylester, N - (2,2-dimethoxy-1 - hydroxyethyl) acrylamide, N-dimethylainopropyl acrylamide, N-

Dimethylaminopropyl methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-butyl acrylamide, N-butyl methacrylamide, N-cyclohexyl acrylamide, N-

Cyclohexyl methacrylamide, N-dodecyl acrylamide, N-dodecyl methacrylamide,

Ethylimidazolidone methacrylate, N-vinylformamide, N-vinylpyrrolidone and the like.

Further organic polymers suitable for the preparation of the polymer dispersions according to the invention come from the group of styrene-butadiene rubbers (SBR). Such rubbers are produced by copolymerization of styrene and butadiene and generally contain the two monomers in a weight ratio of about 23.5 to 76.5 or about 40 to 60. The SBR are usually produced by emulsion polymerization in water.

Another suitable group of polymers are the polyvinyl acetates (PVAc). The polyvinyl acetates are thermoplastic polymers of vinyl acetate. The polymerization is generally carried out by suspension or emulsion polymerization.

Another suitable group of polymers are the polyethylene homopolymers and copolymers. A radical polymerization of ethylene is carried out, for example, as part of the high-pressure polymerization to LDPE at pressures of about 1,400 to 3,500 bar at temperatures of 150 to 350 ° C. The reaction is started by oxygen or peroxides. Linear or branched α, β-unsaturated olefins are suitable as comonomers.

Another group of suitable polymers are the polyacrylic acid esters or the methacrylic acid esters or copolymers of polyacrylic acid esters and polymethacrylic acid esters. If appropriate, the polymers mentioned can still have small proportions (up to about 10%) of free acrylic acid or methacrylic acid groups.

Another polymer suitable as part of the polymer dispersions which can be used according to the invention is polyvinylidene chloride. The polymer is preferably obtained by emulsion polymerization of 1,1-dichloroethylene. Are particularly suitable Copolymers of 1,1-dichloroethylene with acrylates, methacrylates, vinyl chloride or acrylonitrile.

Another suitable polymer is polyvinylidene fluoride. The polymer can be obtained by polymerizing vinylidene fluoride and can be adapted in terms of chemical and mechanical properties, for example by copolymerization with suitable monomers such as ethylene, acrylonitrile, acrylate testers, methacrylate testers and the like.

Also suitable are the polyvinyl chlorides such as those obtainable by emulsion polymerization (E-PVC).

In the context of the present invention, the polymers mentioned can be present in the polymer dispersion contained in component A both individually and as a mixture of two or more thereof.

In a preferred embodiment of the invention, a copolymer of vinyl acetate and ethylene (EVA copolymer) is used as the organic polymer. In a further preferred embodiment of the invention, the polymer dispersion in component A contains polyvinyl acetate or polyacrylate, in particular polybutyl acrylate or a mixture of polyvinyl acetate and polyacrylate.

The polymer dispersion which can be used in component A contains the abovementioned polymers which can be prepared by emulsion polymerization in an amount of at least about 30% by weight. In the context of a preferred embodiment of the present invention, the proportion of such polymers is at least about 35 or at least about 40% by weight. However, the content of such polymers can also be higher, for example at least about 45% by weight or at least about 50% by weight or higher, for example at least about 55 or at least about 60% by weight.

In addition to water and the organic polymers that can be prepared by emulsion polymerization, component A also contains at least one protective colloid or a mixture of two or more protective colloids. As a protective colloid etherified cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose or carboxymethyl cellulose are suitable. Also suitable are polyvinylpyrrolidone or polycarboxylic acids such as polyacrylic acid or polymethacrylic acid, if appropriate in the form of their copolymers with esters of acrylic acid or methacrylic acid optionally carrying OH groups, and copolymers of maleic acid or maleic anhydride with other ethylenically unsaturated compounds such as methyl vinyl ether or styrene. In the context of a preferred embodiment of the present invention, component A contains as protective colloid polyvinyl alcohol, for example polyvinyl alcohol with a degree of hydrolysis of about 30 to about 100% by weight, for example about 60 to about 98% by weight or about 70 to about 88% by weight. -%, or a mixture of two or more such polyvinyl alcohols.

As described above, component A suitable protective colloids can contain, for example, only one protective colloid. However, it is equally possible within the scope of the present invention that a component A which can be used according to the invention contains a mixture of two or more of the protective colloids mentioned.

In the context of a preferred embodiment of the present invention, component A contains a protective colloid carrying OH groups. In a further preferred embodiment of the present invention, the component contains polyvinyl alcohol or a mixture of two or more polyvinyl alcohols with different degrees of hydrolysis as a protective colloid.

The total proportion of the protective colloid or protective colloids in the total component A is about 0.1 to about 20, for example about 0.5 to about 15 or about I to about 10% by weight.

Component A contained in the context of a multicomponent adhesive according to the invention also contains at least one water-soluble, acidic metal salt. Suitable salts are, for example, the nitrates, chlorides, oxychlorides or sulfates of aluminum, iron, chromium, titanium, zirconium or vanadium. In the context of a preferred embodiment of the present invention, in particular the salts of aluminum, chromium or zirconium, for example aluminum chloride, AJumimurn nitrate, chromium chloride or zirconium oxychloride are used. In the context of the present invention, the acidic metal salts mentioned can each be used alone or as a mixture of two or more thereof.

The corresponding salts are present in an amount of about 0.05 to about 20% by weight, based on the total component A, for example about 0.1 to about 10% by weight or about 0.2 to about 5% by weight. %, used. A solution of the corresponding metal salts is advantageously stirred into component A.

In the context of a preferred embodiment of the invention, the corresponding metal salt or a mixture of two or more of the corresponding metal salt is added in an amount such that the pH of component A is about 1 to about 5. In the context of a further preferred embodiment of the invention, the pH of component A is about 2 to about 4.5, for example about 2.5 to about 3.8.

If the pH of component A is to remain stable over a long period of time, it has proven to be advantageous if component A is added to a buffer system. Suitable buffer systems for the dispersion are, for example:

Carbonate / bicarbonate

Sodium acetate / acetic acid,

Monopotassium citrate (KH ₂ citrate),

Monosodium phosphate / citric acid.

In a further preferred embodiment of the invention, component A can also contain at least one ionic surfactant. In a further preferred embodiment of the invention, such an ionic surfactant has a molecular weight of less than about 600.

Anionic, cationic or ampholytic surfactants, or mixtures of two or more thereof, can be present. Examples of suitable anionic surfactants are alkyl sulfates, in particular those with a chain length of about 8 to about 18 carbon atoms, alkyl and alkaryl ether sulfates with about 8 to about 18 carbon atoms in the hydrophobic radical and 1 to about 10 ethylene oxide (EO) or propylene oxide (PO) units, or their Mixture, in the hydrophilic part of the molecule, sulfonates, in particular alkyl sulfonates, with about 8 to about 18 carbon atoms, alkylarylsulfonates with about 8 to about 18 carbon atoms, taurides, esters and half esters of sulfosuccinic acid with monohydric alcohols or alkylphenols with 4 to about 15 carbon atoms, which can optionally be ethoxylated with 1 to about 20 EO units, alkali and ammonium salts of carboxylic acids, for example fatty acids or resin acids with about 8 to about 32 carbon atoms or their mixtures, phosphoric acid partial esters and their alkali and ammonium salts.

In a preferred embodiment of the invention, component A contains, as anionic surfactants, alkyl and alkaryl phosphates with about 8 to about 22 carbon atoms in the organic radical, alkyl ether or alkaryl ether phosphates with about 8 to about 22 carbon atoms in the alkyl or alkaryl radical and 1 to about 10 EO units.

Examples of cationic surfactants are salts of primary, secondary or tertiary fatty amines with about 8 to about 24 carbon atoms with acetic acid, sulfuric acid, hydrochloric acid or phosphoric acids, quaternary alkyl and alkylbenzene ammonium salts, especially those whose alkyl groups have about 6 to about 24 carbon atoms have, in particular the halides, sulfates, phosphates or acetates, or mixtures of two or more thereof, alkylpyridinium, alkylimidazolinium or alkyloxazolidinium salts, in particular those whose alkyl chain has up to about 18 carbon atoms, for example the halides, sulfates, phosphates or Acetates, or mixtures of two or more thereof.

Examples of ampholytic surfactants are long-chain substituted amino acids such as N-alkyl-di (aminoethyl) glycine or N-alkyl-2-aminopropionic acid salts, betaines such as N- (3-acylamidopropyl) -N, N-dimethylammonium salts with a C ₈ . ₁₈ -acyl radical or

Alkylimidazolinium.

In the context of a further embodiment of the present invention, component A contains one or more of the following anionic surfactants: the alkali metal salts, in particular the Na salt of the C _12/14 fatty alcohol ether sulfates, alkylphenol ether sulfates, in particular their alkali metal or NH ₄ salts, Na n-dodecyl sulfate, di-K-oleic acid sulfonate (C ₁₈ ), Na-n-alkyl- (C ₁ oC ₁ ) -benzenesulfonate, Na-2-ethylhexyl sulfate, NH4-lauryl sulfate (C _8/1 ), Na lauryl sulfate (Cι _2/1 ), Na lauryl sulfate (C ₁₂ / ι ₆ ), Na lauryl sulfate (C ₁ / ι ₈ ), Na cetylstearyl sulfate (Ci _{6 /} ιβ), Na -Oleylcetyl sulfate (C ₁₆ / ι ₈ ), sulfosuccinic acid monoester di-Na salt, fatty alcohol sulfosuccinate-di-Na salt, dialkyl sulfosuccinate Na salt or di-Na sulfosuccinamate or mixtures of two or more thereof.

If component A contains ionic surfactants, they are in a preferred embodiment of the invention in an amount of up to about 1.5% by weight or less, for example up to about 0.8% by weight or about 0, 5 wt .-%, or less, based on the total component A. If appropriate, smaller amounts of ionic surfactant can also be present, for example up to about 0.2% by weight or below, for example about 0.1% by weight, 0.05% by weight or 0.02% by weight ,

In a further preferred embodiment, component A can contain at least one nonionic surfactant with a molecular weight of less than about 600.

Examples of nonionic surfactants are alkyl polyglycol ethers, preferably those with about 8 to about 20 EO units and alkyl radicals with about 8 to about 20 C atoms, alkylaryl polyglycol ethers, preferably those with about 8 to about 40 EO units and about 8 to about 20 C. -Atoms in the alkyl or aryl residues, ethylene oxide / propylene oxide (EO / PO) block copolymers, preferably those with about 8 to about 40 EO or PO units, addition products of alkylamines with alkyl residues from about 8 to about 22 carbon atoms with ethylene oxide or propylene oxide, fatty and resin acids with about 6 to about 32 carbon atoms, alkyl polyglycosides with linear or branched, saturated or unsaturated alkyl radicals with an average of about 8 to about 24 carbon atoms and an oligoglycoside residue with about 1 to about 10 hexose - or pentose units on average or mixtures of two or more thereof, natural products and their derivatives such as lecithin, lanolin or sarcosine, linear organo (poly) siloxanes containing polar groups, ins especially those with alkoxy groups with up to about 10 C atoms and up to about 20 EO or PO groups.

Non-ionic surfactants are suitable, for example nonylphenol ethoxylates, octylphenol ethoxylates, _{C12 /} ι ₄ fatty alcohol ethoxylates, Cι _6/18 - Fatty alcohol ethoxylates, cetylstearylethoxylates, ethoxylated triglycerides,

Sorbitan monolaurate, sorbitan monooleate, sorbitan 20EO monooleate, sorbitan 20EO monostearate or a mixture of two or more thereof.

In the context of a further preferred embodiment of the present invention, component A which can be used according to the invention, for example in addition to or instead of a buffer system, also contains one or more compounds which react with a strong mineral acid, such as, for example, when using the acidic metal salts in Can be released within the scope of the present invention, reacting while neutralizing them. Amines are suitable for this purpose, for example, which can be reacted with a mineral acid under protonation. Suitable amines are, for example, primary, secondary or tertiary amines, which may also have one or more functional groups. Amines which have one or more OH functionalities, for example ethanolamine, diethanolamine or in particular triethanolamine, are particularly suitable. Also suitable are compounds with at least one epoxy group, which are also suitable for this purpose.

For example, epoxidized natural fats or fatty acids, such as those sold by the Henkel company under the name Edenol®, are particularly suitable. The products Edenol D81, Edenol D82 and Edenol D83, which are characterized in the following table, are particularly suitable:

In a further preferred embodiment of the invention, the dispersion contains up to about 30% by weight, based on the total dispersion, of additives. The additives include, for example, stabilizers, defoamers, antioxidants, photostabilizers, pigment distributors, fillers, pH regulators, plasticizers and the like.

Suitable plasticizers are, for example, esters such as abietic acid esters, adipic acid esters, azelaic acid esters, benzoic acid esters, butyric acid esters, acetic acid esters, esters of higher fatty acids with about 8 to about 44 carbon atoms, esters with OH groups or epoxidized fatty acids, fatty acid esters and fats, glycolic acid esters, phosphoric acid esters, phthalic acid esters , from 1 to 12 carbon atoms containing linear or branched alcohols, propionic acid esters, sebacic acid esters, sulfonic acid esters, thiobutyric acid esters, trimellitic acid esters, citric acid esters, and mixtures of two or more thereof. The asymmetric esters of difunctional, aliphatic or aromatic dicarboxylic acids are particularly suitable, for example the esterification product of monoctyl adipate with 2-ethylhexanol (Edenol DOA, from Henkel, Düsseldorf) or the esterification product of phthalic acid with butanol.

Also suitable as plasticizers are the pure or mixed ethers of monofunctional, linear or branched C _4.16 alcohols or mixtures of two or more different ethers of such alcohols, for example dioctyl ether (available as Cetiol OE, from Henkel, Düsseldorf). In a further preferred embodiment, end-capped polyethylene glycols are used as plasticizers. For example, polyethylene or polypropylene glycol di-C _M alkyl ether, in particular the dimethyl or diethyl ether of diethylene glycol or dipropylene glycol, and mixtures of two or more thereof.

Component A according to the invention can also contain up to about 10% by weight of conventional tackifiers. Suitable tackifiers are, for example, resins, terpene oligomers, coumarone / indene resins, aliphatic, petrochemical resins and modified phenolic resins.

Component A according to the invention can contain up to about 2% by weight, preferably about 1% by weight, of UV stabilizers. The so-called hindered amine light stabilizers (HALS) are particularly suitable as UV stabilizers.

In a further preferred embodiment of the invention, component A according to the invention has approximately

20 to 70 wt .-% of a producible by emulsion polymerization

Polymers or a mixture of two or more thereof

0.5 to 15% by weight of a protective colloid or a mixture of two or more protective colloids

0.05 to 20% by weight of a water-soluble, acidic metal salt or a mixture of two or more thereof,

29.44 to 79.44 wt% water

0 to 0.5% by weight of a nonionic surfactant,

0 to 0.1% by weight of an ionic surfactant and about

0 to 30% by weight of other additives.

In a preferred embodiment of the present invention, the polymer dispersion contained in component A is prepared by emulsion polymerization. In the context of the present invention, “emulsion polymerization” means a process for polymerization in which water is insoluble or poorly soluble soluble monomers are emulsified in water with the aid of emulsifiers and polymerized using water-soluble initiators. Suitable processes for emulsion polymerization are described, for example, in Comprehensive Polymer Chemistry, 4, 171-218, Elias (5th edition), 2, 93ff. Encyclopedia of Polymer Science and Engineering, 12, 512ff. or Encyclopedia of Polymer Science and Technology, 5, 801 ff. Further suitable references are known, for example, from the lexical reference works known to the person skilled in the art, Ullmann's encyclopedia of industrial chemistry, Houben-Weyl (E20, 218-268) or Kirk-Othmer. Reference is hereby expressly made to the cited references and the disclosure of the cited references is regarded as part of the disclosure of the present text.

Both water-soluble and oil-soluble polymerization initiators can be used as polymerization initiators in the preparation of the polymer dispersions according to the invention. Water-soluble initiators such as tert-butyl hydroperoxide, sodium peroxodisulfate, peroxodisulfuric acid, cumene hydroperoxide, azo compounds such as diazoisobutyric acid clinitrile or benzoyl peroxide are particularly suitable as polymerization initiators. Redox initiators are also suitable, i. i.e. systems consisting of oxidizing and reducing agents. In many cases, water-soluble redox initiators contain transition metals, e.g. B. Fe / HO (I), but it can also contain other base components, for. B. the systems peroxysulfates / metabisulfates, peroxysulfates / thiosulfates or peroxides / thiosulfates.

In a preferred embodiment of the invention, sodium persulfate, potassium persulfate or ammonium persulfate are used as polymerization initiators.

The amount of polymerization initiator used in the context of the present invention is generally from about 0.01 to about 0.5% by weight, based on the total dispersion. In a preferred embodiment of the invention, the total amount of polymerization initiator used is about 0.03 to about 0.2% by weight, for example about 0.05 to about 0.15% by weight. In the context of the present invention, the total amount of the polymerization initiator can already be present in the dispersion of the filler particles at the start of the polymerization. In a preferred embodiment of the invention, however, the polymerization initiator is added in at least two batches at different times in the polymerization reaction. So z. B. the addition of part of the total amount of the polymerization initiator before the monomer addition, while the addition of the remaining amount can be done in portions or continuously during the monomer addition, or after the monomer addition has ended.

The further constituents contained in the polymer dispersion, for example protective colloids, surfactants and additives, can be added before, during or after the emulsion polymerization.

The crosslinking resins can also be added before, during or after the emulsion polymerization. In the context of a preferred embodiment of the present invention, however, the crosslinking resins are added before or during the polymerization process. The addition can take place, for example, shortly before the start or at the start of the polymerization reaction. It has been shown that the addition of the crosslinking resin before or during the polymerization process leads to products whose storage stability at high temperatures, for example at about 30 to about 50 ° C., is increased compared to products in which the crosslinking resin has been added after the polymerization ,

A composition which can be used as component A according to the invention can essentially have any consistency. For example, it is possible within the scope of the present invention that a component A according to the invention has a Brookfield viscosity of a few mPas, for example at least about 50 or at least about 100 mPas. However, it is also possible according to the invention that a composition which can be used as component A has an essentially pasty or creamy consistency. Such compositions can have, for example, a Brookfield viscosity of several Pas, for example up to about 25 or up to about 50 Pas. In the context of a preferred embodiment of the present invention, however, a composition which can be used as component A has one Brookfield viscosity of about 1000 to about 20,000, especially about 2000 to about 15,000 or about 5000 to about 12,000 mPas.

In addition to the components already mentioned, a multi-component adhesive according to the invention also has at least one component B which contains at least one crosslinking resin or a mixture of two or more crosslinking resins.

Suitable crosslinking resins in the context of the present invention are, for example, phenol-formaldehyde resins or hydroxymethyl-substituted urea ethers, hydroxymethyl-substituted melamines, hydroxymethyl-substituted benzoguanamines, hydroxymethyl-substituted pyrimidinones or hydroxymethyl-substituted triazinones, for example 1,3-dimethylol-4, 5-dihydroxyimidazolidone (4,5-dihydroxy-N, N'-dimethylolethyleneurea) or dihydroxymethylethyleneurea,

Dihydroxymethylpropylene urea or dihydroxymethyluron or their thio derivatives or self-condensation products thereof or a mixture of two or more thereof.

Suitable phenol-formaldehyde resins can be obtained by reacting phenol or phenol derivatives with formaldehyde or formaldehyde derivatives with an increase in molecular weight. The production of such phenol-formaldehyde resins follows the general rules of inorganic chemistry and is known to the person skilled in the art. Phenol-formaldehyde resins suitable in the context of the invention have, after crosslinking in a preferred embodiment of the invention, a softening point (ring and ball) of approximately 80 to approximately 130 ° C., for example approximately 90 to approximately 120 ° C.

Phenol-formaldehyde resins suitable as part of component B in the context of the present invention have OH groups on the aromatic phenol units. In a preferred embodiment of the present invention, phenol-formaldehyde resins are used which have an OH number of 100 or less, for example about 80, about 60 or about 40 or below, for example about 20 or about 10. In a further preferred embodiment of the invention, the phenol-formaldehyde resins used have less than 10% by weight of free methyl groups, for example less than 8% by weight, less than 6% by weight or less than 4% by weight or less , on. Suitable phenol-formaldehyde resins are themselves dispersible in water and stable as a dispersion over a longer period of time.

In the context of the present invention, those phenol-formaldehyde resins whose phenol units are substituted in the p-position to the OH group can also be used as a component of component B. Linear or branched, saturated or unsaturated alkyl chains with 1 to about 22 C atoms are suitable as substituents.

The phenol-formaldehyde resins suitable as a component of component B in the context of the present invention are usually sold as aqueous emulsions with a solids content of up to about 60% by weight. In a further preferred embodiment of the present invention, emulsions are used which have a viscosity of about 50 to about 100 poise with a solids content of about 45 to about 55% by weight and a pH of about 6.5 to about 7, 5 have. Suitable phenol-formaldehyde resins are available, for example, under the name Resin XR 14277 A (manufacturer: CECA / ELF-Atochem). It is an aqueous emulsion of a reactive phenolic resin with a low free formaldehyde content (less than 0.1%). It is a milky, white to slightly yellowish product with a viscosity in the range from 60 to 80 poise and a pH in the range from 7 to 7.5, which has a solids content of 49 to 52% by weight.

Also suitable are the crosslinking resins of the types HRJ and SP, for example SP-8025, which are sold by Schenectady International, in particular the resins:

HRJ-11112 (terpene / phenol base) with a Brookfield viscosity of 300-750, a particle size of about 0.5 to about 3.0 μm, a solids content of about 39 to about 47% and a pH of about 9-10 as well

HRJ-10416 (alkyl / phenol-based) with a Brookfield viscosity of 1200-2750, a particle size of about 1.0 to about 5.0 μm, a solids content of about 51 to about 57% and a pH of about 4.5 - 6.5.

Other types of crosslinking resin which are suitable as a component of component B are crosslinking resins based on hydroxymethyl-substituted imidazolidinones, such as 1,3-dimemylol-4,5-dihydroxyimidazolidinone (4,5-dihydroxy-N, N'-dimethylolethylene urea). , Hydroxymethyl-substituted pyrimidinones or Hydroxymethyl-substituted triazinones or their self-condensation products or mixed condensates of two or more of the compounds mentioned, or a mixture of two or more of the compounds mentioned. Crosslinking resins of this type are commercially available, for example, under the names Fixapret, Stabitex, Permafresh, Sarcoset, Sumitex, Prox, Knittex, Cassurit, Neuperm or Depremol.

In a further embodiment of the present invention, the compounds of the Fixapret series are used as crosslinking resins, for example Fixapret C-PX, Fixapret COC, Fixapret CP 40 IGD, Fixapret CPK IGD, Fixapret CPNS IGD, Fixapret CP IGD or Fixapret CPN IGD. The compounds mentioned are usually used as aqueous emulsions or solutions with a solids content of between about 30 and 50% by weight. In a preferred embodiment, the pH is about 7.5 to about 9.

Fixapret C-PX is a polycondensation product of glyoxal-urea-formaldehyde (dimethylglyoxal-urine) in water, with a pH of 8.0 to 8.5, a solids content of 40 to 42% by weight, a free formaldehyde content of less than 1.1% by weight, a density of 1.03 to 1.06 g / cm ³ , an apha color number of at most 50, which does not cause precipitation in the presence of MgCl.

In the context of a further preferred embodiment of the invention, the polymer dispersion contains a crosslinking resin based on 1,3-dimethylol-4,5-dihydroxyimidazolidinone (4,5-dihyciroxy-N, N'-dimethylolethyler-urea) either in the form of the pure compounds indicated Self-condensation products or a mixture thereof.

Other suitable crosslinking resins are commercially available, for example, in the product range marketed under the name Stabitex (manufacturer: BASF). Basically, all products sold under the above name can be used. In a preferred embodiment of the present invention, however, Stabitex ZF or Stabitex GFA is used as the crosslinking resin. The compounds mentioned are usually used as aqueous emulsions or solutions with a solids content of between about 30 and 50% by weight. In a preferred embodiment the pH is about 7.5 to about 9.

Component B contains the crosslinking resins in an amount of about 10 to about 70% by weight, for example in an amount of 30 to about 50% by weight or about 35 to about 45% by weight.

In a preferred embodiment of the present invention, component B contains 1,3-dimethylol-4,5-dihydroxyimidazolidinone (4,5-dihydroxy-N, N'-dimethylolethylene urea) or dihydroxymethylethylene urea, dihydroxymethylpropylene urea or dihydroxymethyluron or their thio derivatives as crosslinking resins, either in the form the particular compounds indicated, their self-condensation products or mixed condensates of two or more of the compounds mentioned or mixtures of two or more of the compounds or condensates mentioned.

The multicomponent adhesives according to the invention are suitable for bonding the same or different substrates, it being possible to coat or bond both substrates with a smooth surface and substrates with rough or porous surfaces. In the context of a preferred embodiment of the present invention, the multi-component adhesives according to the invention are used for coating or bonding substrates based on natural raw materials, for example for bonding wood, wood-based materials, paper or cardboard.

The multi-component adhesives according to the invention are made available to the consumer to the extent that the individual components of the more component adhesive are contained in separate containers. The different components can be sold separately, for example, so that the consumer can essentially put together the required amounts of resin and hardener. However, it is also provided according to the invention that the individual components A and B are dispensed in separate containers, but in coherent packaging. The latter method has the advantage, especially in the DIY sector, that the amount of resin and hardener within a package can be coordinated with one another in such a way that complete mixing of the individual components creates an optimally effective adhesive.

It is also provided in the context of the present invention that the delivery of the individual components takes place in the context of an adhesive kit. Such an adhesive kit comprises an essentially closed packaging which contains all components of the multicomponent adhesive, for example component A and component B, in a spatially separated arrangement, for example in separate containers or in a cartridge with several separate spaces.

The present invention therefore also relates to an adhesive kit, at least comprising a component A according to the invention and a component B according to the invention in separate containers.

In order to facilitate the mixing of the components present separately from one another to form an adhesive, it may be advantageous to add a mixing device to an adhesive kit according to the invention. Suitable mixing devices are, for example, spatulas or spoons which, in the simplest case, allow the individual components to be mixed in a vessel provided by the user. However, it is also possible to dispense the individual components of the adhesive in mixing devices, for example in a cartridge, it being possible for a corresponding cartridge to have a static mixer, for example in the discharge area.

The more component adhesive according to the invention are suitable for the production of adhesives. For this purpose, the individual adhesive components are mixed in a suitable mixing ratio.

The mixing of the individual components is preferably carried out so that the proportion of crosslinking agent in the total adhesive is about 0.1 to about 15% by weight, in particular about 0.5 to about 10 or about 1 to about 6% by weight.

The crosslinking resins used according to the invention as component B are suitable for producing the multicomponent adhesives according to the invention. The present invention therefore also relates to the use of a crosslinking resin based on phenol-formaldehyde condensates, hydroxymethyl-substituted imidazolidinones or thioimidazolidinones, hydroxymethyl-substituted pyrimidinones or hydroxymethyl-substituted triazinones or the like

Self-condensation products or mixed condensates from two or more of the compounds mentioned, or a mixture of two or more of the compounds mentioned as a component of multicomponent adhesives.

The present invention furthermore relates to the use of a composition comprising at least water, at least one polymer which can be prepared by emulsion polymerization, at least one protective colloid and at least one water-soluble, acidic metal salt as a constituent of multicomponent adhesives.

The invention is explained in more detail below by examples.

Examples

To check the effectiveness of the multicomponent adhesives according to the invention, the formulation examples listed in Table 1 were prepared.

Table 1

DLR = Mowilith DLR (manufacturer: Fa Clariant)

* = A1C1 ₃ was used as a 30% by weight solution in water

Stabitex GFA: manufacturer BASF

Formulation examples 1 to 3 represent examples according to the invention, example 4 was inserted for comparison with non-additive systems.

For comparison, a commercially available dispersion adhesive which meets the EN 204 D3 standard was used as formulation example 5 (Vinnapas LL8525, manufacturer: Wacker, Burghausen).

Formulation examples 1 to 5 were checked in accordance with EN 204 Dl to D3. The results obtained are summarized in Table 2.

Table 2

* = Test specimens have fallen apart

Target values of EN 204 as well as the positioning sequence according to which the following was checked: EN 204 D1 should> 10 N / mm ² dry binding strength, positioning sequence 1 EN 204 D2 target> = 8 N / mm ² wet binding strength, positioning sequence 2 EN 204 D3 target> = 2 N / mm ² wet binding strength, positioning sequence 3

The formulation examples were also examined for the parameters listed below. The results are summarized in Table 3.

Table 3

Pot life check of formulation examples No>. 1 to 4

In each case a composition according to formulation examples 1 to 4 was stored at 23 ° C. for 21 days and then examined for the parameters listed below. The properties of the bonds are summarized in Table 4. Table 4: Measurements after 21 days storage at 23 ° C

The test methods mentioned in the examples are described as follows:

Determination of the open time

The measurement is carried out on conditioned, undamped solid beech (Fagus sylvatica) with a wood moisture of 8-10% and an adhesive application of 200μ.

For measurement, the adhesive to be tested, stored at 23 ° C, is applied with a spiral knife under constant climatic conditions at 23 ° C and 50% relative humidity. The adhesive film is tested for skin formation at intervals of one minute. If skin formation can be seen, one minute is deducted from the determined value. To check the determined value, the adhesive is then tested in accordance with DIN EN 204, the test specimen being produced in accordance with DIN EN 205. To produce the test specimen, the test specimen is then left open at 23 ° C. and 50% relative humidity after application of the adhesive, and is pressed immediately thereafter. If the relevant stress group of DIN EN 204 is met, the determined open time is considered secured.

Specification: time [min.]

Determination of heat resistance measured according to watt 91

Test specimens according to DEN EN 205 are produced with the adhesive to be tested. Then, in accordance with DIN EN 204 Dl, position sequence 1, they are tested in the warmth of a tensile shear test. In deviation from DIN EN 204 Dl, the test specimen is not torn apart at room temperature but in the warmth. For this purpose, the test specimens to be tested are stored for 1 h at 80 ° C in a circulating air drying cabinet. After removing the test specimen, the test specimen must be torn in a ripping machine within 10 seconds to prevent heat loss. The feed speed of the ripping machine is 50 mm / min.

Specification: tensile shear strength [N / mm ² ]

Determination of water resistance

DIN EN 204 dated October 1991, assessment of adhesives for non-load-bearing components for joining wood and wood-based materials

Specification: tensile shear strength [N / mm ² ], stress group, position sequence

Determination of viscosity

Measured according to Brookfield RTV-DV U ISO 2555 at 23 ° C

Specification [mPas] pH measurement according to DIN 53785

Microprocessor pH meter pH 537 WTW pH meter CG 818, Schott single-rod measuring chain type N 61. Calibration before measurement. Measurement at 23 ° C

Determination of hardwood gluing

The test is carried out on butt-glued solid, undamped beech (Fagus sylvatica) with a wood moisture content of 8-10%. For this purpose, 5 beechwoods with the dimensions 1 = 20 cm, w = 4 cm, h = 2 cm are glued together so that a total area of 20 by 20 cm is created. The wood has to be conditioned for at least 3 months under constant conditions at 23 ° C and 50% relative humidity. The wooden parts are bonded under defined climatic conditions at 23 ° C and 50% relative humidity, whereby the adhesive itself should also have a temperature of 23 ° C. The adhesive is applied on one side with a 200μ spiral knife. The parts are joined immediately after application of the adhesive. The pressure should be between 0.6 and 0.7 N / mm ² . The pressing time depends on the adhesive system. After subsequent storage for 7 days at 23 ° C. 50% atmospheric humidity, the fracture pattern is then assessed after deliberate destruction of the test body in the glue joint (gap test).

Specification: wood quarry [%]

Solids content according to DIN 53189 / ISO 1625

Evaluation:

Dry residue [g] Dry residue [%] X 100%

Weight [g]

Specification : [%]

MFT according to DIN 53787 / ISO 2115

Testing the tendency to discoloration on wood, caused by the adhesive system

The adhesive to be tested is applied in a layer thickness of 250 μ to the wood to be tested using a squeegee. Drying and storage take place at 23 ° C and 50% relative humidity. After 7 days, the adhesive film and the wood are examined for discoloration. As a comparison, the adhesive is applied under the same conditions on a neutral surface, e.g. Glass, applied.

Specification: type of wood, discoloration yes / no

Claims

claims

1. Multi-component adhesive with at least 2 components A and B, where a) component A at least one polymer dispersion containing water, at least one polymer which can be prepared by emulsion polymerization, at least one protective colloid, at least one water-soluble, acidic metal salt and b) component B at least one crosslinking resin based of phenol-formaldehyde condensates, hydroxymethyl-substituted imidazolidinones or Thioimidazolidinonen, hydroxymethyl-substituted Harnstoffethem, hydroxymethyl-substituted melamines, hydroxymethyl substituted benzoguanamines, hydroxymethyl-substituted pyrimidinones or hydroxymethyl-substituted triazinones or self-condensation products thereof or mixed condensates of two or more of said Compounds, or contains a mixture of two or more of the compounds mentioned.

2. Multi-component adhesive according to spoke 1, characterized in that the polymer dispersion has a pH of 1 to 5.

3. Multi-component adhesive according to spoke 1 or 2, characterized in that component A contains an aluminum, a chromium or a zirconium salt or a mixture of two or more of the salts mentioned as the water-soluble, acidic metal salt.

4. Multi-component adhesive according to one of claims 1 to 3, characterized in that the polymer dispersion contains a protective colloid carrying OH groups.

5. Multi-component adhesive according to one of claims 1 to 4, characterized in that the polymer dispersion contains at least 50 wt .-% of a polymer produced by emulsion polymerization.

6. Multi-component adhesive according to one of claims 1 to 5, characterized in that the polymer dispersion contains polyvinyl acetate or a copolymer produced using vinyl acetate as a polymer which can be prepared by emulsion polymerization.

7. Multi-component adhesive according to one of claims 1 to 6, characterized in that component B as crosslinking resin 1,3-dimethylol-4,5-dihydroxyimidazolidinone (4,5-dihydroxy-N, N'-dimethylolethylene urea) dihydroxymethylethylene urea, dihydroxymethylpropylene urea or dihydroxymethyluron, Monohydroxymethyl urea, dihydroxymethyl urea, hydroxymethyl-substituted urea ethers, hydroxymethyl-substituted melamines, hydroxymethyl-substituted benzoguanarnines, hydroxymethyl-substituted pyrimidinones or hydroxymethyl-substituted triazinones either in the form of the specified compounds, or as a mixture of two or more thereof, the self-condensation products of the individual crosslinking agents Contains condensation products from two or more of the crosslinking resins mentioned.

8. Adhesive kit, comprising at least two components A and B, where a) as component A at least one polymer dispersion containing water, at least one polymer which can be prepared by emulsion polymerization, at least one protective colloid, at least one water-soluble, acidic metal salt and b) at least one as component B. Crosslinking resin based on phenol-formaldehyde condensates, hydroxymethyl-substituted imidazolidinones or thioimidazolidinones, hydroxymethyl-substituted pyrimidinones or hydroxymethyl-substituted triazinones or their self-condensation products or mixed condensates of two or more of the compounds mentioned, or a mixture of two or more of the compounds mentioned , is included and the individual components are spatially separated from each other.

9. Adhesive kit according to claim 8, characterized in that it comprises a mixing device.

10. Use of a crosslinking resin based on phenol-formaldehyde condensates, hydroxymethyl-substituted imidazolidinones or thioimidazolidinones, hydroxymethyl-substituted pyrimidinones or hydroxymethyl-substituted triazinones or their self-condensation products or mixed condensates of two or more of the compounds mentioned, or a mixture of two or more of the compounds mentioned as a component of multicomponent adhesives.

11. Use of a composition containing at least water, at least one polymer which can be prepared by emulsion polymerization, at least one protective colloid and at least one water-soluble, acidic metal salt as a constituent of multicomponent adhesives.