EP0000776A1 - Adhesive composition capable of absorbing and permeable to water vapour, process for its preparation and its use - Google Patents

Abstract

The invention relates to an adhesive which is improved in water vapor absorption capacity and permeability and is based on at least one organic, water-insoluble binder and optionally an organic solvent and / or water. These adhesives contain an additive made from at least one small-sized, hydrophilic, swellable, modified polymer. These swellable, modified polymers are in particular at least about 50% by weight water-insoluble; They preferably include swellable, modified carbohydrate derivatives, such as starch or cellulose ethers crosslinked using thermal energy, radiation or an additional chemical compound. In a process for the production of such adhesives, the particles of at least one swellable, modified polymer are added to the adhesive matrix before they are processed and distributed evenly therein, and the mixture is then spread or otherwise deformed. The adhesives according to the invention are particularly suitable for bonding flat materials in the production and processing of coated textiles and natural and synthetic leathers.

Description

Water vapor absorbent and water vapor permeable adhesive, a process for its production and its use

The invention relates to an adhesive with an additive made of a hydrophilic polymer which is improved in water vapor absorption capacity and permeability, a process for its production and its use

When an adhesive is applied to a substrate and then bonded to a second substrate of the same or a different type, a water vapor-impermeable barrier, caused by the adhesive film, occurs in most cases between the two substrates. In particular when manufacturing and processing coated textiles (e.g. for all-weather clothing or tarpaulins) and natural and synthetic leathers (e.g. for shoe upper material, shoe lining, cushion cover and outer clothing), one of the decisive requirements for the material is that it is capable of absorbing water vapor and is permeable, for example in order to produce a good wearing comfort and a good wearing climate on the body. The necessary use of adhesives in the manufacture and processing of these materials inevitably leads to certain disadvantages with regard to the properties mentioned. There has been no shortage of attempts to overcome this disadvantage.

• 1. Perforierung der Klebstoffschicht durch Einbringen winziger Löcher in die Schicht. Die Durchlässigkeit der Klebstoffschicht fUr Wasserdampf ist dann jedoch zuf die perforierten Teile der Schicht beschränkt und die übrigen Teile der Schicht bleiben undurchlässig, außerdem beeinflußt dieses.Verfahren die Aufnahmefähigkeit der Schicht für Wasserdampf nicht oder nur in geringem Maß.
• 2. Aufbringen des Klebstoffes auf ein Substrat in der Art, daß dieser das Substrat nur unvollständig, z. B. in einzelnen Flecken, Strichen oder Punkten, bedeckt. Dieses Verfahren beeinflußt aber die Klebefestigkeit zwischen zwei Substraten in großem Maße, so daß der Einsatz dieses Verfahrens auf wenige Spezialgebiete beschränkt bleibt. Außerdem verbleiben die weiter oben geschilderten Nachteile an den mit Klebstoff bedeckten Stellen.
• 3, Bei der Anwendung lösemittelhaltiger Klebstoffe kann das Lösemittel so aus der Klebstoffschicht entfernt werden, daß diese mit einer gewissen Porosität zurückbleibt. Dieses Verfahren liefert zwar in gewissem Umfang wasserdampfdurchlässige Klebeschichten, es verläuft jedoch nur bei exakter VerfahrensfUhrung in befriedigender Weise und ergibt oftmals unregelmäßig aufgebaute Schichten, so daß die Klebefestigkeit zwischen zwei Substraten ungleichförmig sein kann. Außerdem ist die Wasserdampfaufnahmefähigkeit auch diesen Schichten sehr beschränkt.
• 4. Dem Klebstoff wird ein hydrophiles Polymeres beigemischt, das die geforderten Eigenschaften im Klebstoff bewirken soll. Dieses Verfahren ist aber auf bestimmte Klebstofftypen beschränkt und liefert zwar brauchbare Werte in der Wasserdampfdurchlässigkeit, nicht jedoch in der Wasserdampfaufnahmefähigkeit.

Basically four methods have become known with the help of which it is possible to achieve the required properties:

• 1. Perforation of the adhesive layer by making tiny holes in the layer. However, the permeability of the adhesive layer to water vapor is then restricted to the perforated parts of the layer and the remaining parts of the layer remain impermeable, moreover this influences the process of the layer's ability to absorb water vapor, or only to a small extent.
• 2. Applying the adhesive to a substrate in such a way that the substrate is incomplete, e.g. B. covered in individual spots, lines or dots. However, this process influences the adhesive strength between two substrates to a large extent, so that the use of this process remains limited to a few special fields. In addition, the disadvantages described above remain in the areas covered with adhesive.
• 3, When using solvent-based adhesives, the solvent can be removed from the adhesive layer so that it remains with a certain porosity. Although this method provides to a certain extent water-vapor-permeable adhesive layers, it only runs satisfactorily if the method is carried out exactly and often results in irregularly structured layers, so that the adhesive strength between two substrates can be non-uniform. In addition, the water vapor absorption capacity of these layers is very limited.
• 4. A hydrophilic polymer is added to the adhesive, which is said to bring about the required properties in the adhesive. However, this method is limited to certain types of adhesive and provides useful values in water vapor permeability, but not in water vapor absorption capacity.

DT-PS 1 006 558 describes an adhesive composed of a butadiene copolymer (butadiene-methyl-isopropenyl ketone copolymer) and a cellulose derivative. Suitable cellulose derivatives are cellulose esters, such as cellulose nitrate or acetate, and cellulose ethers, such as benzyl cellulose. The amount of the above-mentioned, usually film-forming cellulose derivatives should be 25 to 75% by weight of the copolymer, the adhesives produced in this way should have a high binding power.

In the process for producing adhesives based on water-soluble, highly polymeric, hydroxyl-containing substances according to DT-AS 10 75 773, this substance is reacted in finely divided form with a crosslinking aldehyde or ketone until it becomes insoluble in water or becomes water-soluble dissolves more slowly, but is still swellable with water, and then a smaller part of the substance treated in this way is mixed with a larger part of the adhesive based on water-soluble cellulose derivatives. Cellulose derivatives, in particular cellulose ether, modified starch, vegetable gum or polyvinyl, are intended for this process be suitable for alcohol. Improvements in spreadability and gliding properties are mentioned as favorable properties in terms of application technology.

From DT-OS 18 09 124 an adhesive is known which contains a water-soluble or water-swellable hydrocolloid or a mixture of such hydrocolloids and a water-insoluble, viscous, natural or synthetic, rubber-like binder. Suitable hydrocolloids are polyvinyl alcohol, pectin, gum arabic, gelatin, alginates, carboxymethyl cellutose, polyethylene glycols, carboxypolymethylene and polyoxyethylene. The adhesive should adhere immediately to a wide variety of wet surfaces and their adhesive properties. also do not lose if dry surfaces covered with the adhesive become damp.

DT-AS 23 64 125 describes a pressure-sensitive adhesive mixture which consists of 90 to 99 parts by weight of a tacky copolymer of an alkyl acrylate whose alkyl group contains 1 to 14 carbon atoms, the average number of carbon atoms being 4 to 12 a double bond and thus copolymerizable monomers and 10 to 1 parts by weight of a hydroxyethyl cellulose. The use of this adhesive mixture as a gas- and moisture-permeable adhesive layer on a gas- and moisture-permeable substrate for the production of pressure-sensitive, breathable adhesive tapes or adhesive sheet-like materials is mentioned as an area of application.

The object of the invention is to propose an adhesive which is improved and permeable to water vapor and which is improved over the prior art and which can contain the most diverse binders in different adhesive systems.

The invention is based on a water vapor-absorbent and permeable adhesive containing at least one organic, water-insoluble binder, an addition of at least one hydrophilic polymer and optionally an organic solvent and / or water. The adhesive according to the invention is characterized in that the hydrophilic polymer is a small-sized, swellable, modified polymer. Swellable polymers are understood to mean those which swell in aqueous liquids, in particular with a water content of more than 50% by weight, or are caused by water molecules (eg water vapor) which come into contact with them in some other way. In particular, the polymer is at least about 50% by weight water-insoluble.

In a preferred embodiment, the adhesive contains about 5 to 30% by weight of these polymers, based on the total dry adhesive mass.

• Vernetztes Polyalkylenoxid nach der DT-OS 20 48 721; beim Verfahren zur Herstellung dieses Produkts werden wasserlösliche Polyalkylenoxide mit einer genügend starken ionisierenden Strahlung behandelt, um eine Vernetzung und ein Unlöslichwerden des Polymeren zu erreichen. Die

The following are suitable as small-particle, ie in particular powdery or fibrous swellable, modified polymers with a size of ≦ 250 _/ μm, preferably of ⁼ 150 μm, in the adhesive according to the invention:

• Cross-linked polyalkylene oxide according to DT-OS 20 48 721; in the process of making this product, water-soluble polyalkylene oxides are treated with sufficient ionizing radiation to achieve crosslinking and insolubility of the polymer. The

Irradiation can take place with the polyalkylene oxide in the solid state or in solution.

wobei n = 0, 1 oder 2 ist. Als α, β-ungesättigte Säure sind dabei insbesondere Acrylsäure, Methacrylsäure, Itaconsäure, α-Phenylacrylsäure oder α-Benzylacrylsäure geeignet; bei der Herstellung des Mischpolymerisats werdenzweckmäßig auf 85 % bis 99,9 % einer der ungesättigten Säuren 0,1 % bis 15 % des Acetals verwendet.The absorbent, crosslinked, carboxyl group-containing copolymer according to DT-OS 25 07 011 from an α, β-unsaturated acid and an acetal of the general formula

where n = 0, 1 or 2. Acrylic acid, methacrylic acid, itaconic acid, α-phenylacrylic acid or α-benzylacrylic acid are particularly suitable as α, β-unsaturated acid; in the preparation of the copolymer it is expedient to use 0.1% to 15% of the acetal to 85% to 99.9% of one of the unsaturated acids.

A hydrocolloid polymer according to US Pat. No. 3,670,731 (= DT-OS 16 42 072) which has been rendered water-insoluble by crosslinking and is suitable for taking up and also holding back liquids; in particular certain polyacrylamides alkali metal salts of hydrolyzed polyacrylamides and alkali metal salts of polystyrene sulfonates are mentioned.

A water-swellable, crosslinked, insoluble, physiologically harmless polymer according to US Pat. No. 3,669,103 (= DT-OS 16 17 998) from the group of poly-N-vinylpyrrolidones, polyacrylamides, polyacrylic acid and polyglycols. According to the process of DT-OS 25 41 035, at least for the most part water-insoluble, water-swellable absorbent polymers which are prepared in such a way that etherified in a homogeneous phase polyhydroxymethylene in an aqueous alkaline solution with an α-halocarboxylic acid and before, during or after etherification with a polyfunctional crosslinking agent compared to polyhydroxymethylene in an alkaline medium.

In particular, the following swellable, modified carbohydrate derivatives can be used in the context of the invention: alkali metal salts of carboxymethyl cellulose which are heat-treated and swellable in water according to US Pat. No. 2,639,239; in the process of making this product, the solubility of a water-soluble alkali metal salt of carboxymethyl cellulose, which has a D.S. (= Degree of substitution, ie number of substituted hydroxyl groups on an anhydro-D-glucose unit) from 0.5 to about 1, reduced by this dry salt in finely divided form at a temperature of about 130 ° to about 210 ° C. exposes, whereby highly swellable gel particles are obtained.

• a) Cellulosematerialien mit carboxyalkylierenden Reaktionsteilnehmern behandelt und hierdurch wasserlösliche Carboxyalkylcellulose mit einem mittleren Substitutionsgrad von mehr als 0,35 Carboxyalkylresten pro Anhydroglucoseeinheit in der Cellulose, aber mit schlechten Eigenschaften in Bezug auf Aufsaugung und Zurückhaltung von Flüssigkeiten bildet,
• b) einen solchen Teil der carboxyalkylierenden Reaktionsteilnehmer und während der Reaktion gebildeten Nebenprodukte entfernt, daß, bezogen auf das Gewicht der wasserlöslichen Carboxyalkylcellulose, wenigstens etwa 3 Gew.-% davon zurückbleiben, und
• c) die Carboxyalkylcellulose in Gegenwart der verbliebenen carboxyalkylierenden Reaktionsteilnehmer und Nebenprodukte der Reaktion einer Wärmebehandlung unterwirft und sie hierdurch wasserunlöslich macht und ihr ausgezeichnete Eigenschaften in Bezug auf Aufsaugung und Zurückhaltung von Flüssigkeiten verleiht.

Water-insoluble, liquid-absorbing and retaining, heat-treated carboxyalkyl celluloses according to US Pat. No. 3,723,413 (= DT-OS 2 314 689); in the process for the preparation of these products, the procedure is such that

• a) Treated cellulose materials with carboxyalkylating reactants and thereby forms water-soluble carboxyalkyl cellulose with an average degree of substitution of more than 0.35 carboxyalkyl residues per anhydroglucose unit in the cellulose, but with poor properties with regard to absorption and retention of liquids,
• b) removing such a part of the carboxyalkylating reactants and by-products formed during the reaction that at least about 3% by weight thereof remain, based on the weight of the water-soluble carboxyalkyl cellulose, and
• c) the carboxyalkyl cellulose is subjected to a heat treatment in the presence of the remaining carboxyalkylating reactants and by-products of the reaction and thereby renders them water-insoluble and gives them excellent properties with regard to absorption and retention of liquids.

Absorbent carboxymethyl cellulose fibers which are suitable for use in fiber materials for the absorption and retention of aqueous solutions and are essentially water-insoluble according to US Pat. No. 3,589,364 (= DT-OS 1 912 740); such fibers consist of wet crosslinked fibers of water-soluble salts of carboxymethyl cellulose with a D.S. from about 0.4 to 1.6 and have the original fiber structure. About 3 to 10% by weight epichlorohydrin is preferably used as the crosslinking agent.

die Chlor-azomethingruppe

oder die Allyloxy-azomethingruppe

sind oder das Dichloressigsäure oder Phosphoroxychlorid ist.Chemically cross-linked, swellable cellulose ether according to US Pat. No. 3,936,441 (= DT-OS 2,357,079); these cross-linked cellulose ethers, in particular from carboxymethyl cellulose, carboxymethyl-hydroxyethyl cellulose, hydroxyethyl cellulose or methyl hydroxyethyl cellulose, are prepared in such a way that the ether, which is water-soluble per se, is reacted in an alkaline reaction medium with a crosslinking agent whose functional groups are the acrylamido group

the chloro-azomething group

or the allyloxy azomething group

are or that is dichloroacetic acid or phosphorus oxychloride.

• I
  
  oder
  
  wobei in Formel I: R₁ = die Hydroxyl-, eine Acylamino-oder eine veresterte Carbaminogruppe und R₂ = Wasserstoff oder die Carboxylgruppe bedeuten.

Chemically modified, swellable cellulose ether according to US Pat. No. 3,965,091 (= DT-OS 2,358,150); these cellulose ethers, which have not been modified by crosslinking, are prepared in such a way that the per se water-soluble ethers are reacted in an alkaline reaction medium with a monofunctionally reacting compound which is described by one of the following two general formulas:

• I.
  
  or
  
  where in formula I: R ₁ = the hydroxyl, an acylamino or an esterified carbamino group and R ₂ = hydrogen or the carboxyl group.

Chemically cross-linked, swellable cellulose ether according to DT-OS 2 519 927; these crosslinked cellulose ethers are prepared in such a way that the water-soluble xers are reacted in an alkaline reaction medium with bisacrylamidoacetic acid as the crosslinking agent.

• a) mindestens ein wasserlösliches pulvriges polymeres Kohlenhydrat mit einer solchen Menge mindestens eines pulvrigen inerten Füllmittels, dessen Teilchen kleiner als die des Kohlenhydrates sind, so vermischt, daß ein wesentlicher Teil der Oberfläche des pulvrigen Kohlenhydrats bedeckt ist,
• b) unter Fortsetzen des Mischens das Gemisch unter gründlichem Rühren mit einem feinverteilten Wasserspray in einer solchen Menge in Berührung bringt, bei der das Gemisch in einer frei fließenden Teilchenform erhalten bleibt, und
• c) dann das erhaltene Gemisch bis zur Vernetzung des polymeren Kohlenhydrats einer ionisierenden Strahlung aussetzt.

Free-flowing, radiation-crosslinked, water-swellable hydrophilic carbohydrates according to DT-AS 2 264 027; these products are produced in such a way that (with the following reaction stages, similar products can also be obtained with certain other polymers, such as polyethylene oxide or polyvinyl alcohol):

• a) at least one water-soluble powdery polymeric carbohydrate is mixed with such an amount of at least one powdery inert filler, the particles of which are smaller than those of the carbohydrate, such that a substantial part of the surface of the powdery carbohydrate is covered,
• b) while continuing to mix, mix the mixture with a finely divided water spray in such an amount with thorough stirring which maintains the mixture in a free flowing particle form, and
• c) then exposing the resulting mixture to ionizing radiation until the polymeric carbohydrate has crosslinked.

die Acrylamidogroppe, wobei R₁= H oder CH₃ ist, oder

eine α-Halogen-epoxygruppe wobei Hal = Cl oder Br ist oder

die Chlor-azomethingruppe oder

die Allyloxy-azomethingruppe oder das Phosphoroxychlorid ist. Eine andere Art der Herstellung verläuft derart, daß die Modifizierung mit einer unter den genannten Bedingungen gegenüber den Hydroxylgruppen der Stärke oder des Stärkeäthers monofunktionell reaktionsfähigen Verbindung durchgeführt wird, die durch eine der folgenden allgemeinen Formeln beschrieben wird:

oder

wobei R₁ = CH₃ oder H und R₂ = H und R₃ = CH₃, CH₂-O^H, eine N-Methylen-acylamidogruppe mit 1 bis 3 C-Atomen, eine veresterte N-Methylen-carbamido- oder N-Carboxymethylen-carbamidogruppe mit 2 bis 7 C-Atomen ist, oder R₂ und R₃ = CH₃ oder CH₂-OH sind und wobei R₄ und R₅ = H oder R₄ = H und R₅ = CH₃ oder R₄ und R₅ = CH₃ sind.Chemically cross-linked or otherwise modified, swellable starch ether according to DT note. P 26 34 539.1; these special starch ethers are made so that, for. B. as a modification, a crosslinking is carried out with a crosslinking agent which bears the following functional group which is reactive toward hydroxyl groups:

the acrylamido group, where R ₁ = H or CH ₃ , or

an α-halogen epoxy group where Hal = Cl or Br or

the chloro-azomething group or

is the allyloxy azomething group or the phosphorus oxychloride. Another type of preparation is such that the modification is carried out with a compound which is monofunctionally reactive under the conditions mentioned with respect to the hydroxyl groups of the starch or the starch ether, which is described by one of the following general formulas:

or

where R ₁ = CH ₃ or H and R ₂ = H and R ₃ = CH ₃ , CH ₂ -O ^H, an N-methylene-acylamido group with 1 to 3 C atoms, is an esterified N-methylene-carbamido or N-carboxymethylene-carbamido group having 2 to 7 C atoms, or R ₂ and R ₃ = CH ₃ or CH ₂ -OH and where R ₄ and R ₅ = H or R ₄ = H and R ₅ = CH ₃ or R ₄ and R ₅ = CH ₃ .

Alkali metal salts of carboxymethyl cellulose with increased absorption and retention capacity according to US Pat. No. 3,678,031 (= DT-OS 21 51 973). Although etherification agents containing carboxyl groups are used, which would result in a normally soluble cellulose ether, the conditions of the reaction are chosen such that alkali metal salts of carboxymethyl cellulose with a DS of 0.4-1.2, a water-soluble fraction of <35%, a water retention value (WRV) of about 1,000 to 7,000 and a salt water retention value of about 400 to about 2,500.

Water-insoluble carboxymethyl celluloses as used in DT-PS 10 79 796 and DT-AS 11 51 474, i. H. those of a D. S. of 0.05 to 0.3 and those which are essentially water-insoluble and also have a low D. S.

Water-insoluble, more polymerized carboxymethyl or carboxyethyl cellulose with a substantial content of free carboxyl groups according to GB-PS 725 887 (= DT-PS 10 37 076) which are made water-insoluble by heating the water-soluble, acidic compounds to 80 ° C to 177 ° C .

Phosphorylated cellulose fibers according to DT-OS 24 47 282, as can be produced by reacting cellulose pulp with urea and phosphoric acid under the action of heat, followed by acidic hydrolysis and a final transfer into the salt form.

Dry, solid, water-swellable, water-insoluble absorbents according to DT-OS 26 09 144, which consist of an ionic complex of a water-insoluble anionic polyelectrolyte and a cation of at least 3-valent metal; polyacrylic acid, starch or cellulose derivatives are suitable as polyelectrolytes.

Cellulose graft polymers according to DT-OS 25 16 380, which are produced by grafting the cellulose side chains from such polymer residues that are selected from the ionic and nonionic polymer residues. The following are suitable, for example: polyacrylic acid, sodium polyacrylate, polymethacrylic acid, potassium polymethacrylate, polyvinyl alcohol sulfate, polyphosphoric acid, polyvinylamine, poly- (4-vinylpyridine), hydrolyzed polyacrylonitrile, polymethyl methacrylate, polyvinyl acetate, polystyrene or polybutadiene.

Granulated, water-insoluble alkali metal carboxylate salts of starch-acrylonitrile graft copolymers according to US Pat. No. 3,661,815, which are prepared by saponification of starch-acrylonitrile graft copolymers with a base in an aqueous alkaline medium. Modified cellulose material with improved retention for both water and physiological liquids according to DT-OS 25 28 555, which by grafting an olefinically unsaturated, polymerizable monomer with hydrolyzable functional groups or a monomer carrying carboxyl groups onto a fibrous cellulose material and hydrolyzing or otherwise treating the grafted product is made with alkali. The product is first brought into the state of maximum swelling, then acidified to a pH at which it has the state of minimal swelling, then converted into the salt form under conditions not causing swelling and finally dried.

Modified polysaccharide according to DT-OS 26 47 420, made from polysaccharide, acrylamide, another vinyl monomer and a divinyl monomer under radical reaction conditions.

• - Lösemittelklebstoffe, sie enthalten den Grundstoff gelöst in organischen Lösemitteln; sie binden physikalisch durch Verdunsten der in ihnen enthaltenen Lösemittel ab,
• - Dispersionsklebstoffe, sie enthalten den Grundstoff dispergiert in Wasser und/oder einer anderen zusammenhängenden flüssigen Phase; sie binden physikalisch durch Verdunsten des Wassers und/oder der anderen Phase ab,
• - Zweikomponentenklebstoffe, sie bestehen aus zwei Klebstoffkomponenten, die, unmittelbar vor Gebrauch gemischt, auf die Klebflächen aufgetragen werden; eine der beiden Klebstoffkomponenten kann z. B. ein Kunststoff- oder Kautschuk-Klebstoff, die andere der "Härter" oder "Vernetzer" z. B. ein Polyisocyanat sein; beide Komponenten gehen nach ihrem Mischen eine chemische Umsetzung z. B. eine Vernetzung ein,
• - Schmelzklebstoffe, sie sind nichthärtende, schmelzbare Harze und enthalten in der Regel kein Lösemittel; der Klebfilm wird durch Schmelzen und Erstarren erhalten.

The adhesive base materials themselves, processes for their production and various adhesive methods are known. The adhesives in the context of this invention include in particular:

• - Solvent adhesives, they contain the base material dissolved in organic solvents; they bind physically by evaporation of the solvents they contain,
• - Dispersion adhesives, they contain the base material dispersed in water and / or another coherent liquid phase; they bind physically by evaporation of the water and / or the other phase,
• - Two-component adhesives, they consist of two adhesive components which, when mixed immediately before use, are applied to the adhesive surfaces; one of the two adhesive components can e.g. B. a plastic or rubber adhesive, the other of the "hardener" or "crosslinker" z. B. be a polyisocyanate; after mixing, both components undergo a chemical reaction, e.g. B. a networking,
• - Hotmelt adhesives, they are non-curing, meltable resins and usually do not contain any solvents; the adhesive film is obtained by melting and solidifying.

The basic materials for the adhesives according to the invention are organic, water-insoluble binders, in particular based on natural or synthetic rubber or a semi-synthetic or synthetic polymer. Examples include: Cellulose esters such as nitrocellulose or acetyl cellulose, rubber in latex form or in solid, comminuted form, rubber components and polyisocyanate components, butadiene-styrene and acrylonitrile copolymers, polychlorobutadiene (= polychloroprene), Polyesters, polyisocyanates, polyisocyanate components and hydroxy-polyester components, polyurethanes, polyvinyl chloride, polyisobutylene, polyvinyl acetals, polyvinyl acetate, polyvinyl ethers and polyacrylic and polymethacrylic acid esters.

• Alkohole wie Methanol oder Äthanol; Ketone wie Aceton, Methyl-äthylketon, Cyclohexanon oder Methyl-cyclohexanon; Ester wie Essigsäure-methylester, -äthylester, -cyclohexylester oder -methylglykolester; Kohlenwasserstoffe wie Benzine, Benzol oder Toluol; Chlorkohlenwasserstoffe wie Methylenchlorid, Tetrachlorkohlenstoff, Di- oder Trichloräthan; Tetrahydrofuran oder Schwefelkohlenstoff einzeln oder im Gemisch von zwei oder mehreren von ihnen.

The following are used as organic solvents, for example:

• Alcohols such as methanol or ethanol; Ketones such as acetone, methyl ethyl ketone, cyclohexanone or methyl cyclohexanone; Esters such as methyl acetate, ethyl ester, cyclohexyl ester or methyl glycol ester; Hydrocarbons such as gasoline, benzene or toluene; Chlorinated hydrocarbons such as methylene chloride, carbon tetrachloride, di- or trichloroethane; Tetrahydrofuran or carbon disulphide individually or as a mixture of two or more of them.

The adhesives can u. a. also contain plasticizers, agents for increasing the adhesiveness, reaction accelerator or slower reaction, liquefier, fillers, extenders or dyes.

• - Naßkleben, dabei werden die Substrate mit dem in nassem Zustand befindlichen Klebstoff zusammengefügt, d. h. eine oder beide Klebstoffschichten enthalten noch wesentliche Anteile an Löse- oder Dispergiermittel,
• - Kontakt-Kleben, dabei wird der Klebstoff auf die beiden zu verklebenden Flächen von zwei Substraten aufgetragen; nach einer gewissen Zeitspanne ("Trockenzeit") bilden die aufgetragenen Klebstoffschichten, beim Berühren scheinbar trocken, innerhalb einer u. a. von Temperatur und Luftfeuchte abhängigen Zeitspanne ("offene Zeit" oder "Kontaktklebezeit") beim Zusammenlegen unter geringem Druck Klebungen sofort meßbarer Festigkeit,
• - Wärmeaktivier-Kleben, dabei bildet der auf ein Substrat aufgetragene Klebstoff nach dem Trocknen klebfreie ("nichtblockende") Klebschichten, die bei ausreichendem Erwärmen klebfähig werden und sich unter Druck mit einem anderen Klebstoffgemisch oder einem zweiten Subtrat verbinden und nach dem Abkühlen eine feste, dauerhafte Klebung bilden,
• - Lösungsmittelaktivier-Kleben, dabei bildet der auf ein Substrat aufgetragene Klebstoff nach dem Trocknen klebfreie ("nichtklebende") Klebstoffschichten, die durch Befeuchten mit Lösemitteln wieder klebfähig gemacht werden und sich unter Druck mit einem anderen Klebstoffaufstrich oder einem zweiten Substrat verbinden und nach dem Verdunsten des Lösemittels eine feste, dauerhafte Klebunq bilden.

The following are the most common adhesive methods:

• Wet gluing, in this case the substrates are joined with the glue which is in the wet state, ie one or both layers of glue still contain substantial amounts of solvent or dispersant,
• - contact bonding, the adhesive is applied to the two surfaces to be bonded by two substrates; after a certain period of time ("drying time"), the applied adhesive layers, apparently dry when touched, form bonds of immediately measurable strength within a period of time which is dependent on temperature and humidity ("open time" or "contact adhesive time") when folded under low pressure,
• - Heat activation bonding, whereby the adhesive applied to a substrate forms non-tacky ("non-blocking") adhesive layers after drying, which become adhesive when heated sufficiently and combine under pressure with another adhesive mixture or a second substrate and, after cooling, form a firm, form permanent bond,
• - Solvent-activating-glue, whereby the glue applied to a substrate forms after drying non-sticky ("non-sticky") layers of glue, which are made sticky again by wetting with solvents and bond under pressure with another glue spread or a second substrate and after evaporation form a strong, permanent adhesive.

For a detailed description of the technology of adhesives and gluing, e.g. B. on Ullmann's Encyclopedia of Chemical Engineering, Verlag Urban & Schwarzenberg - Munich, 1957, Volume 9, 3rd edition, keyword "Adhesives", pages 578 ff.

In some adhesive processes, for example the application of an adhesive layer to a flat structure made of nonwoven fabric, in addition to achieving a adhesive film, the nonwoven particles are also intended to be bonded to one another. The adhesive according to the invention also delivers good results in these applications.

When carrying out the examples, the following adhesives were used in particular (parts are parts by weight, percentages are given in% by weight):

In order to produce the adhesives according to the invention, the particles of at least one swellable, modified polymer, preferably in a proportion of 5 to 30% by weight, based on the total dry adhesive, are added to the basic adhesive compositions to be processed and uniformly therein distributed; the mixture is then spread or otherwise deformed. The term "evenly distributed" is understood to mean a statistical distribution.

When using heat to accelerate drying or to activate adhesive, a certain upper temperature limit should not be exceeded if possible. d. H. the adhesive according to the invention should not be heated to a maximum of about 150.degree. C. for longer than about 10 minutes and not about 120.degree. C. to 130.degree. If the adhesive is in the form of an aqueous or water-containing dispersion, it is advisable to increase the water content of the adhesive before or with the addition of the small-sized, swellable, modified polymers in order to obtain the adhesive in a form which is easy to process.

The adhesives according to the invention have a good ability to absorb and permeable to water vapor, which goes far beyond a pure transport effect of the incorporated parts. In addition, the adhesives also able to release the absorbed water vapor under certain conditions, such as staying in a different climate.

Since the stated properties of the adhesives according to the invention are not based solely on the significantly detectable effect due to the addition of the particles of at least one swellable, modified polymer, but rather u. a. also on the thickness of the adhesive film or coating; dependent, these are expediently produced in a thickness of approximately 0.01 to approximately 0.5 mm, in particular if, in addition to good water vapor absorption capacity, good water vapor permeability is also to be achieved.

The adhesives according to the invention with the properties mentioned are preferably used for the bonding of flat materials in the manufacture and processing of coated textiles and natural and synthetic leathers, that is to say materials which are suitable for those areas of application in which body fluids, such as, for. B. sweat, may occur; these include, for example, outer clothing (all-weather or leather clothing), shoe upper materials, shoe lining or shoe insoles.

• WRV Wasserrückhaltevermögen des quellfähigen, modifizierten Polymeren in Gew.-%, gemessen gegen 2000- fache Erdbeschleunigung, bezogen auf seinen wasserunlöslichen Anteil; das WRV wird nach Eintauchen der Probe in Wasser bestimmt,
• WUA wasserunlöslicher Anteil im quellfähigen modifizierten Polymeren,
• DS Substitutionsgrad, Anzahl der substituierten Hydroxylgruppen an den Anhydro-D-glucose-Einheiten, von 0,0 bis 3,0,
• SV Saugvermögen des quellfähigen modifizierten Polymeren für 1%ige NaCl-Lösung in Gew.-%, bezogen auf sein Gesamtgewicht; das SV wird bestimmt nach Aufsaugen von 1 %iger wäßriger NaCl-Lösung durch die Probe bis zur Sättigung,
• WDD Wasserdampfdurchlässigkeit (nach W. Fischer und-W. Schmidt, "Das Leder", E. Roether-Verlag, Darmstadt, 27, 87 ff (1976)). Innerhalb der Apparatur herrscht eine Temperatur von 32° C, über der Probe ein Normklima - wenn nichts anderes angegeben ist - von 23° C / 50 % relative Feuchte, das von einem über dem Gerät angebrachten Ventilator durch einen leichten Luftstrom immer konstant gehalten wird. Die freie Prüffläche beträgt 10 cm². Auch innerhalb der Apparatur wird mit Hilfe eines Magnetrünrers das Wasser von 32° C und die darüber Befindliche mit Wasserdampf gesättigte Atmosphäre
  
  in Bewegung gehalten. Die Bestimmung der WDD erfolgt durch die Bestimmung der Gewichtsabnahme des Prüfgefäßes mit der Probe. Die WDD wird in mg/cm² · x h (x meist 1, aber auch 8 oder 24) angegeben.
• WDA Wasserdampfaufnahme (siehe auch WDD). Die Wasserdampfaufnahme wird gleichzeitig mit der WDD-Messung durchgeführt, die Bestimmung erfolgt durch Ermittlung der Gewichtszunahme der Probe; wenn nichts anderes angegeben ist, ist die Probe zum Außenklima hin durchlässig, d. h. sie wird nicht abgedeckt.

The parameters used in the description and examples for characterizing the adhesives according to the invention and the swellable, modified polymers present in them are to be understood as follows:

• WRV water retention capacity of the swellable, modified polymer in% by weight, measured against 2000 times gravitational acceleration, based on its water-insoluble fraction; the WRV is determined after immersing the sample in water,
• WUA water-insoluble fraction in the swellable modified polymer,
• DS degree of substitution, number of substituted hydroxyl groups on the anhydro-D-glucose units, from 0.0 to 3.0,
• SV Suction rate of the swellable modified polymer for 1% NaCl solution in% by weight, based on its total weight; the SV is determined after absorbing 1% aqueous NaCl solution through the sample until saturation,
• WDD water vapor permeability (after W. Fischer and -W. Schmidt, "Das Leder", E. Roether-Verlag, Darmstadt, 27, 87 ff (1976)). Inside the apparatus there is a temperature of 32 ° C, above the sample there is a standard climate - unless stated otherwise - of 23 ° C / 50% relative humidity, which is always kept constant by a fan installed above the device by a slight air flow. The free test area is 10 cm ² . With the help of a magnetic stirrer, the water inside the apparatus is also kept at 32 ° C and the atmosphere above it saturated with water vapor
  
  kept moving. The determination of the WDD is carried out by determining the weight loss of the test vessel with the sample. The WDD is given in mg / cm ² xh (x mostly 1, but also 8 or 24).
• WDA water vapor absorption (see also WDD). The water vapor absorption is carried out simultaneously with the WDD measurement; the determination is made by determining the weight gain of the sample; unless otherwise stated, the sample is permeable to the outside climate, ie it is not covered.

In all of the following examples, chemically crosslinked sodium carboxymethyl celluloses with the following parameters WUA ≧ 70%, WRV = 400 to 700%, SV = 800 to 1,400%, DS = 0.8 to 1, were used as representative modified, swellable polymers with bisacrylamidoacetic acid. 1 and a particle size of = 200 microns with a proportion of 90 wt .-% of ≦ 100 microns used.

Examples 1 to 4 and comparative examples V 1 and V 2 (see table)

Adhesive films according to the invention are produced and examined for their water vapor permeability and absorption capacity and compared with similar adhesive films without additives. The adhesives are structured as follows:

In all cases, the additive according to the invention results in a significant increase in the WDD and WDA values, which increase as the amount of the additive increases.

Examples 5 to 10 and comparative examples V 3 to V 8

According to DIN 53 273 (in the draft from March 1976) the peel resistance L of adhesives with and without the additive according to the invention is determined. The peeling resistance L is the force, based on the adhesive joint of a sample, that is necessary to separate the sample in the peeling test. The respective substrate samples are made of rubber and / or leather, the surfaces are cleaned and roughened, and strips of 150 mm × 30 mm are punched out of the substrates. The adhesive is stored at 23 ° C ^t 2 ° C until it has reached this temperature and then depending on its type on the or the southeast rate applied and processed so that two substrate strips are glued to a length of 100 mm. The non-glued ends of the samples are bent on both sides and clamped to a length of 20 mm in the tensile testing machine. The two ends are pulled apart at a feed rate of 100 mm / min. The peel resistance L is the force that results as a value or mean value for several samples over the separation path, ie
L = value of the force read during separation in N sample width in mm

The adhesives are structured as follows:

According to DIN 53 273, the adhesives mentioned provide the following peeling resistances (in N / mm) when test rubber / test rubber is bonded: 9.6 (example V3), 9.5 (example 5), 8.7 (example V5) and 8.4 (Ex. 7); with a test rubber / test leather bond: 8.7 (Ex. V4), 8.9 (Ex. 6), 8.3 (Ex. V6) and 8.4 (Ex. 8); with a test leather / test leather bond: 1.5 (example V7), 1.5 (example 9), 1.3 (example V8) and 1.4 (example 10). The peeling resistances do not change, or change only to an insignificant extent, so that the adhesive strength of the adhesives is at most only slightly influenced by the additive according to the invention.

Examples 11 to 13 and Comparative Example V 9

Polyester staple fibers (polyethylene glycol terephthalate, 1.3 dtex, 38 mm long) are processed via carding machine and stacker to a fleece with a weight per unit area of approximately 150 g / m ² and slightly mechanically consolidated in a needle needle chair. The needled fleece is bound with an aqueous polyurethane-containing medium (binder content about 65 to 70 wt .-%, based on the fiber content), for. B. dip impregnated on the padder with the following components: aqueous polyurethane dispersion, anionic and nonionic emulsifier, aqueous Ca (N0 ₃ ) ₂ solution, leather dye and (in the examples, but not in the comparative example) an addition of the modified, swellable polymer . The polyurethane can represent both the binder for the fleece and an adhesive layer on the bound fleece. The impregnated fleece is dried at about 110 ° C. for about 50 minutes.

Claims (9)

1. Water vapor-absorbent and permeable adhesive containing at least one organic, water-insoluble binder, an additive of at least one hydrophilic polymer and optionally an organic solvent and / or water, characterized in that the hydrophilic polymer is a small-sized, swellable, modified polymer. 2. Adhesive according to claim 1, characterized in that the swellable, modified polymer is at least about 50 wt .-% water-insoluble. 3. Adhesive according to claim 1 or 2, characterized in that the swellable, modified polymer is a carbohydrate derivative. 4. Adhesive according to one of claims 1 to 3, characterized in that the swellable, modified polymer is a starch or cellulose ether. 5. Adhesive according to one of claims 1 to 4, characterized in that the swellable, modified polymer is a starch or cellulose ether crosslinked with the aid of thermal energy, radiation or by an additional chemical compound. 6. Adhesive according to one of claims 1 to 5; characterized in that it is about 5 to 30 wt .-%, based on contains the entire dry adhesive mass of swellable, modified polymer. 7. A method for producing a water vapor-absorbent and permeable adhesive according to claim 1, characterized in that the adhesive base, the particles of at least one swellable, modified polymer are added before their processing and evenly distributed therein and the mixture is then spread or otherwise deformed. 8. The method according to claim 7, characterized in that the particles in a proportion of 5 to 30 wt .-%, based on the total dry adhesive mass, are added. 9. Use of the adhesive according to claim 1 for the bonding of flat materials in the manufacture and processing of coated textiles and natural and synthetic leathers.