WO2025040620A1

WO2025040620A1 - Waterborne adhesive composition

Info

Publication number: WO2025040620A1
Application number: PCT/EP2024/073203
Authority: WO
Inventors: Christoph Thiebes; Fred Buckmann; Ronald Tennebroek; Roel SWAANS; Lex DONDERS; Zhirong FAN; Jan Weikard; Peter Kueker; Wolfgang Arndt
Original assignee: Covestro Deutschland Ag
Priority date: 2023-08-21
Filing date: 2024-08-19
Publication date: 2025-02-27
Also published as: TW202515965A

Abstract

The present invention is directed to a waterborne dispersion for use in an adhesive composition, wherein the dispersion comprises dispersed polymer particles comprising both (i) a polyurethane and (ii) a vinyl polymer, wherein said dispersed particles comprising the polyurethane and the vinyl polymer in a weight ratio of the polyurethane to the vinyl polymer higher than 1, and the polyurethane-vinyl polymer comprises a crystalline phase having a melting temperature in the range from 30 to 80 °C and an enthalpy of fusion of at least 15 J/g, whereby the melting temperature and the enthalpy of fusion are determined by differential scanning calorimetry according to DIN EN ISO 11357-1:2017 (2017-02) at a heating rate of 20 K/min.

Description

WATERBORNE ADHESIVE COMPOSITION

The present invention relates to a waterborne dispersion comprising dispersed polymer particles comprising both (i) a polyurethane and (ii) a vinyl polymer; and to the use of such a dispersion in an adhesive composition.

Adhesives based on aqueous polyurethane dispersions have become established worldwide in demanding industrial applications, for example in shoe manufacturing, the bonding of parts for motor vehicle interiors, the bonding of furniture parts or the adhesive bonding of textile substrates.

In the case of the use of such dispersions for bonding substrates, this is usually carried out after the heat-activation process. In this case, the dispersion is applied to the substrate, and usually after at least partly evaporation of the water, the adhesive layer is activated by heating, for example using an infrared radiator, and is converted into an adhesive state. The temperature at which the adhesive film becomes sticky is referred to as the activation temperature. The heat-activation process is customary for laminating adhesives, as for example for interior automotive components or for laminating hard PVC foil to furniture parts. Soft PVC is frequently used for interior automotive components, therefore the bond strength and the heat resistance of the adhesive when bonding soft PVC are important adhesive performance parameters. Since soft PVC contains high amounts of plasticizer, adhesion of soft PVC is cumbersome, and improving the performance of adhesive for bonding soft PVC is desired. Wood or wood composite coated with a hard PVC foil is often used for furniture components, therefore the bond strength and the heat resistance of the adhesive when bonding wood or wood composite to hard PVC are also important parameters for the adhesive performance.

EP1167454 B1 describes aqueous dispersion adhesives containing multiphase particles of polyurethane and a copolymer and/or terpolymer produced by emulsion polymerisation of vinyl- and/or acrylic and/or methacrylic monomeric material(s) in a weight ratio between 50:50 and 10:90 (polyurethane to emulsion polymer) for lamination a PVC foil to Medium Density Fibre (MDF) board after heat activation. Two-component (2K) adhesive systems are applied consisting of a first component comprising the aqueous dispersion and a second component comprising a polyisocyanate crosslinker; the crosslinker is added shortly before use of the adhesive composition. It has been found that the bond strength of the 2K adhesive for bonding beech wood to hard PVC foil is low, and also the softening point of the 2K adhesive when applied on plasticized PVC is low. In addition, the described adhesives explicitly require the use of a monomer containing a nitrile group, preferably acrylonitrile as part of the (meth)acrylic phase, which is under scrutiny due to the hazards that exist from handling the monomer during manufacturing and from residual monomers in the dispersion adhesive.

The object of the present invention was to provide multiphase particles comprising polyurethane and vinyl polymer comprising binders for adhesives, in particular 2K adhesives, with increased bond strength and/or heat resistance.

It has surprisingly been found that using waterborne dispersions according to the invention comprising multiphase particles comprising polyurethane and vinyl polymer in a weight ratio of polyurethane to vinyl polymer higher than 1 in adhesive compositions results in an increased bond strength and/or heat resistance, particularly when bonding wood or wood composite to hard PVC foil or when bonding plasticized PVC, compared to using waterborne dispersions comprising a blend of polyurethane and vinyl polymer in the same weight ratio or compared to using waterborne dispersions comprising multiphase particles comprising polyurethane and vinyl polymer in a weight ratio of polyurethane to vinyl polymer lower than 1.

The present invention provides a waterborne dispersion for use in an adhesive composition, wherein the dispersion comprises dispersed polymer particles comprising both (i) a polyurethane and (ii) a vinyl polymer, wherein said dispersed particles comprising the polyurethane and the vinyl polymer in a weight ratio of the polyurethane to the vinyl polymer higher than 1 , and the polyurethane-vinyl polymer comprises a crystalline phase having a melting temperature in the range from 30 to 80 °C and an enthalpy of fusion of at least 15 J/g, whereby the melting temperature and the enthalpy of fusion are determined by differential scanning calorimetry according to DIN EN ISO 11357-1:2017 (2017-02), at a heating rate of 20 K/min.

It has surprisingly been found that the waterborne dispersions as defined in the present invention are outstandingly suitable for bonding substrates using the heat-activation process.

In the context of the present invention, a polyurethane is a polymer obtained by polymerization of one or more polyols and one or more polyisocyanates, but it also includes those in which also monoamines and/or diamines are used as formation components, possibly as chain extenders. The polyurethanes that can be used in the present invention include polyurethanes as well as polyurethane-ureas. Preferably the polyurethane present in the waterborne adhesive composition of the present invention is polyurethane-urea.

Methods for preparing polyurethanes are known in the art and are described in for example the Polyurethane Handbook 2nd Edition, a Carl Hanser publication, 1994, by G. Oertel. A polymer is referred to as semicrystalline or crystalline when it exhibits a melting peak in DSC measurement in accordance with DIN EN ISO 11357-1:2017 (2017-02) with a heating rate of 20 K/min. The melting peak is caused by the melting of regular substructures in the polymer. The melting temperature and enthalpy of fusion are determined during the first heating up starting from a starting temperature of -100°C in the DSC measurement according to DIN EN ISO 11357-1 :2017 (2017-02) with a heating rate of 20 K/min. When applying the DIN EN ISO 11357-1:2017 (2017-02) to determine the melting temperature and the enthalpy of fusion, the standard part DIN EN ISO 11357-3:2018-07 is used. The melting temperature of the polyurethane-vinyl polymers present in the waterborne dispersion according to the invention is preferably in the range from 30 °C to 80 °C, more preferably in the range from 35 °C to 80 °C, more preferably in the range from 40 °C to 70 °C, particularly preferably in the range from 40 °C to 55 °C, more particularly preferably in the range from 42 °C to 55 °C, very particularly preferably in the range from 45 °C to 55 °C. The enthalpy of fusion of the polyurethane-vinyl polymers present in the waterborne adhesive composition according to the invention or of the polymer layers obtained from the formulations according to the invention is at least 15 J/g, more preferably at least 17 J/g, more preferably at least 18 J/g, more preferably at least 19 J/g, particularly preferably at least 20 J/g. The polyurethane- vinyl polymer preferably has an enthalpy of fusion of at most 100 J/g, more preferably of at most 90 J/g, even more preferably of at most 80 J/g, even more preferably of at most 70 J/g. The first heating is evaluated in order to also detect polymers which crystallize slowly.

For all upper and/or lower boundaries of any range given herein, the boundary value is included in the range given, unless specifically indicated otherwise. Thus, when saying from x to y, means including x and y and also all intermediate values.

The waterborne dispersion according to the present invention comprises dispersed polymer particles comprising at least one polyurethane, usually polyurethane-urea, and at least one vinyl polymer. The polyurethane and the vinyl polymer are present in the dispersed particles in a weight ratio of the polyurethane to the vinyl polymer higher than 1 , preferably in a weight ratio of at least 1.1 , more preferably of at least 1.2. The polyurethane and the vinyl polymer are preferably present in the dispersed particles in a weight ratio of the polyurethane to the vinyl polymer of at most 9, more preferably of at most 8, even more preferably of at most 5, even more preferably of at most 4, even more preferably of at most 3, even more preferably of at most 2.5.

The dispersed particles comprising the polyurethane and the vinyl polymer are advantageously obtained by free radical polymerization of at least one vinyl monomer in the presence of at least one water-dispersed polyurethane thereby obtaining a hybrid of polyurethane and vinyl polymer (polyurethane-vinyl polymer)). Accordingly, the vinyl polymer is advantageously formed in-situ by polymerizing the one or more vinyl monomers in the presence of a preformed aqueous polyurethane dispersion.

By a polyurethane-vinyl polymer hybrid (also referred herein as polyurethane-vinyl polymer) is meant that a vinyl polymer is prepared by the free-radical polymerization of vinyl monomer(s) in the presence of the polyurethane by forming an aqueous dispersion of said polyurethane resin and polymerising one or more vinyl monomers to form a vinyl polymer such that said vinyl polymer becomes incorporated in-situ into said aqueous dispersion by virtue of polymerising vinyl monomer(s) used to form the vinyl polymer in the presence of the polyurethane resin. Vinyl monomer is added before, during and/or after preparation of the polyurethane and the vinyl monomer is polymerized by adding a free radical yielding initiator to polymerize the vinyl monomer in the presence of the polyurethane. Suitable free radical yielding initiators are well known in the art and include mixtures partitioning between the aqueous and organic phases. Suitable free-radical-yielding initiators include inorganic peroxides such as ammonium persulphate, hydrogen peroxide, organic peroxides, such as benzoyl peroxide, alkyl hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; dialkyl peroxides such as di-t-butyl peroxide; peroxy esters such as t-butyl perbenzoate and the like; mixtures may also be used. The peroxy compounds are in some cases advantageously used in combination with suitable reducing agents (redox systems) such as iso-ascorbic acid. Azo compounds such as azobisisobutyronitrile may also be used. Metal compounds such as Fe.EDTA (EDTA is ethylene diamine tetracetic acid) may also be usefully employed as part of the redox initiator system. The amount of initiator or initiator system to use is conventional, e.g. within the range of 0.05 to 6 wt.% based on the weight of vinyl monomer used.

The glass transition temperature T_g of the at least one vinyl polymer of the hybrid and the amount of the at least one vinyl polymer in the polyurethane-vinyl polymer are preferably chosen such that

T_g (°C) of the vinyl polymer x weight fraction of the vinyl polymer in the polyurethane-vinyl polymer is in the range from -30 to +50, preferably in the range from -15 to +40, more preferably in the range from -10 to +35, even more preferably in the range from -5 to +30. Thus, the glass transition temperature T_g of the at least one vinyl polymer of the hybrid and the amount of the at least one vinyl polymer in the polyurethane-vinyl polymer are preferably chosen such that the product obtained by multiplying the T_g (°C) of the vinyl polymer with the amount (weight fraction) of the vinyl polymer in the polyurethane-vinyl polymer is in the range from -30 to 50, preferably in the range from -15 to 40, more preferably in the range from -10 to 35, even more preferably in the range from -5 to 30, As used herein, the glass transition temperature is determined by calculation by means of the Fox equation. Thus, the Tg in Kelvin, of a copolymer having "n" copolymerised comonomers is given by the weight fractions W of each comonomer type and the Tg’s of the homopolymers (in Kelvin) derived from each comonomer (as listed, for example, in J. Brandrup, E.H. Immergut, Polymer handbook 4th edition p. VI 193) according to the equation:

1/T_g = E(W_n/Tg_n).

The calculated Tg in Kelvin may be readily converted to °C.

Preferably at least 80 wt.%, more preferably at least 95 wt.% and most preferably 100 wt.% of the total weight of vinyl monomers used are of a,p-mono-unsaturated vinyl monomers.

Examples of vinyl monomers include but are not limited to 1,3- butadiene; isoprene; styrene; a-methyl styrene; (meth)acrylic amides; vinyl ethers; vinyl esters such as vinyl acetate, vinyl propionate, vinyl laurate; vinyl esters of versatic acid such as VeoVa 9 and VeoVa 10 (VeoVa is a trademark of Resolution); heterocyclic vinyl compounds; alkyl esters of mono- olefinically unsaturated dicarboxylic acids such as di-n- butyl maleate and di-n-butyl fumarate; dialkylitaconates such as dimethyltaconate, diethylitaconate, dibutylitaconate and in particular, esters of acrylic acid or of methacrylic acid of formula CH2=CR⁴-COOR⁵ wherein R⁴ is H or methyl and R⁵ is optionally substituted alkyl of from 1 to 20 carbon atoms (more preferably from 1 to 8 carbon atoms) or cycloalkyl of from 3 to 20 carbon atoms (more preferably from 3 to 6 carbon atoms). Examples of such esters of acrylic acid or of methacrylic acid which are methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate (all isomers), octyl (meth) acrylate (all isomers), 2-ethylhexyl (meth)acrylate, isopropyl (meth)acrylate and n-propyl (meth)acrylate. Preferred monomers of formula CH2=CR⁴- COOR⁵ include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate (all isomers), octyl (meth)acrylate (all isomers), ethyl hexyl acrylate (all isomers) and isobornyl (meth)acrylate. In an embodiment, hydroxyl functional vinyl monomer(s) are used as part of the vinyl monomers, preferably the hydroxyl functional vinyl monomer(s) are used in an amount of from 1 to 20 wt.% or from 1 to 10 wt.% or from 2 to 8 wt.%, relative to the total amount of vinyl monomers. Suitable hydroxyl functional vinyl monomers include, for example, hydroxy(C1 -C4)alkyl (meth)acrylates, such as hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate and hydroxypropyl acrylate; preferably the hydroxy-functional vinyl monomer is hydroxyethyl methacrylate (HEMA). Preferably, at least 30 wt.%, more preferably at least 40 wt.%, more preferably at least 50 wt.%, even more preferably at least 60 wt.%, even more preferably at least 70 wt.% and even more preferably at least 80 wt.% of the total amount of vinyl monomer(s) used to prepare the vinyl polymer is selected from the group consisting of methyl methacrylate, butyl acrylate, butyl methacrylate, ethyl hexyl acrylate, octyl acrylate (preferably 2-octyl acrylate), styrene and mixtures of two or more of said monomers. Preferably, the vinyl monomer(s) used to prepare the vinyl polymer is selected from the group consisting of styrene, methyl methacrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, 2-ethyl hexyl acrylate, 2-octyl acrylate and mixtures of two or more of said monomers. More preferably at least 30 wt.%, preferably at least 50 wt.%, even more preferably at least 60 wt.% and more preferably at least 70 wt.% of the total amount of the vinyl monomer(s) used to prepare the vinyl polymer is styrene, methyl methacrylate, n-butyl acrylate, 2-ethyl hexyl acrylate, 2-octyl acrylate or any mixture of two or more of said monomers. Preferably less than 0.1 wt.% of the total amount of the vinyl monomer(s) used to prepare the vinyl polymer is acrylonitrile, more preferably the vinyl monomer(s) used to prepare the vinyl polymer does not comprise acrylonitrile.

The polyurethane is preferably obtained by the reaction of at least the following components (A1)-(A3) and optionally (A4):

(A1) At least one polyisocyanate,

(A2) At least one isocyanate-reactive compound that contains at least one salt group which is capable to render the polyurethane dispersible in water and/or at least one functional group that can be converted into a salt group which is capable to render the polyurethane dispersible in water ,

(A3) At least one isocyanate-reactive polyol other than (A2), and

(A4) Optionally at least one amino-functional isocyanate reactive compound other than (A2).

Component (A1)

At least one polyisocyanate is used as component (A1). The amount of component (A1) is preferably in the range from 5 to 20 wt.%, more preferably in the range from 6.5 to 15 wt.%, more preferably in the range from 8 to 13 wt.%, relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated. If the polyurethane is obtained by the reaction of (A1), (A2) and (A3) and optionally (A4), the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated is the sum of the weight amounts of components (A1), (A2) and (A3) and, if applied, (A4). Component (A1) comprises any suitable organic polyisocyanate including aliphatic, cycloaliphatic, araliphatic and/or aromatic polyisocyanates. Examples of suitable polyisocyanates include ethylene diisocyanate, 1,5-pentane diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 2,2,4- trimethyl-1 ,6-hexamethylene diisocyanate, isophorone diisocyanate (IPDI), cyclohexane-

1.4-diisocyanate, dicyclohexylmethane diisocyanate such as 4,4’-dicyclohexylmethane diisocyanate (4,4’-H12 MDI), p-xylylene diisocyanate, p-tetramethylxylene diisocyanate (p- TMXDI) (and its meta isomer m-TMXDI), 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4’-diphenylmethane diisocyanate (4,4’-MDI), polymethylene polyphenyl polyisocyanates, 2,4’-diphenylmethane diisocyanate, 3(4)- isocyanatomethyl-1 -methyl cyclohexyl isocyanate (IMCI) and 1,5-naphthylene diisocyanate.

Further examples are derivatives based on the afore mentioned diisocyanates having a uretdione, isocyanurate, carbodiimide, allophanate, biuret, iminooxadiazine dione and/or oxadiazine trione structure with two or more isocyanate groups. Mixtures of the polyisocyanates can be used as well. Preferably, the amount of polyisocyanates with more than two isocyanate groups is below 35 wt.%, more preferably below 20 wt.% and especially below 10 wt.% of the component (A1).

Component (A1) preferably comprises hexamethylene diisocyanate (CAS number 822-06-0) and/or toluene diisocyanate (CAS number 26471-62-5). Component (A1) preferably consists of 1 ,5-pentane diisocyanate (CAS number 4538-42-5), hexamethylene diisocyanate (CAS number 822-06-0), isophorone diisocyanate (CAS number 4098-71-9), dicyclohexylmethane- 4,4’-diisocyanate H12MDI (CAS number 5124-30-1), 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4’-diphenylmethane diisocyanate (4,4’-MDI), or 2,4’-diphenylmethane diisocyanate or of any mixture of any two or more thereof. More preferably, the at least one polyisocyanate according to (A1) comprises (i) 1,5-pentane diisocyanate and/or hexamethylene diisocyanate and (ii) isophorone diisocyanate and/or dicyclohexylmethane- 4,4’-diisocyanate H12MDI.

The polyurethane preferably comprises reacted hexamethylene diisocyanate and/or reacted

1.5-pentane diisocyanate in an amount of in the range from 3 to 19 wt.%, more preferably in the range from 4 to 15 wt.%, more preferably in the range from 4.5 to 13 wt.%, most preferably in the range from 5 to 10 wt.%, whereby the amount of reacted hexamethylene diisocyanate and/or reacted 1,5-pentane diisocyanate is the amount of hexamethylene diisocyanate and 1,5-pentane diisocyanate used to prepare the polyurethane relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated. The polyurethane preferably comprises (I) reacted hexamethylene diisocyanate and/or reacted 1,5-pentane diisocyanate and (II) reacted isophorone diisocyanate and/or reacted dicyclohexylmethane-4,4’- diisocyanate H12MDI in such an amount that the weight ratio of the summed amount of reacted hexamethylene diisocyanate and reacted 1 ,5-pentane diisocyanate to the summed amount of reacted isophorone diisocyanate and reacted dicyclohexylmethane-4,4’- diisocyanate H12MDI in the polyurethane is in the range from 0.25 to 20, more preferably in the range from 1 to 15, more preferably in the range from 1 to 10, most preferably in the range from 1.2 to 8 or in the range from 1.2 to 5 or in the range from 1.2 to 3 or in the range from 1.2 to 2, whereby the amount of reacted compound x is the amount of compound x used to prepare the polyurethane relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated.

Component (A2)

At least one isocyanate-reactive compound that contains at least one salt group, preferably a salt of an acidic group, which is capable to render the polyurethane dispersible in water and/or at least one functional group, preferably an acidic group, that can be converted, by reaction with a neutralizing agent, into a salt group which is capable to render the polyurethane dispersible in water is used as component (A2).

In general, the amount of component (A2) is in the range from 0.5 to 3.5 wt.%, preferably in the range from 0.6 to 2.5 wt.%, more preferably in the range from 0.7 to 2.0 wt.%, relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated.

In case component (A2) contains at least one functional group that can be converted by reaction with a neutralizing agent into a salt group, the neutralizing agent used to deprotonate (neutralize) the functional groups (preferably carboxylic acid groups, sulfonic acid groups and/or phosphoric acid groups, more preferably carboxylic acid groups) is preferably selected from the group consisting of ammonia, a (tertiary) amine, a metal hydroxide and any mixture thereof. Suitable tertiary amines include triethylamine and N,N- dimethylethanolamine. Suitable metal hydroxides include alkali metal hydroxides, for example lithium hydroxide, sodium hydroxide and potassium hydroxide. Preferably, at least 30 mol%, more preferably at least 50 mol% and most preferably at least 70 mol% of the total molar amount of the neutralizing agent is alkali metal hydroxide, preferably selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide and any mixture thereof. Preferably the neutralizing agent used to deprotonate (neutralize) the carboxylic acid groups, sulfonic acid groups and/or phosphoric acid groups is an alkali metal hydroxide. As used herein, the neutralizing agent (if any) is not to be considered a component from which the building blocks of the polyurethane are emanated. Thus, the amount of neutralizing agent (if any) used in the preparation of the polyurethane is not taking into account for the calculation of the weight of the polyurethane.

According to the present invention, the acidic group is preferably selected from a carboxylic acid group, a sulfonic acid group and/or a phosphoric acid group. Preferably, component (A2) is selected from the group consisting of compounds having two hydroxy groups next to the acidic group(s), compounds having two amino groups next to the acidic group(s), compounds having a hydroxy group and an amino group next to the acidic group(s) and any mixture thereof.

Preferred components (A2) are dihydroxy alkanoic acids, diamine carboxylates and diamine sulfonate salts. Preferred dihydroxy alkanoic acids are a,a-dimethylolpropionic acid and/or a,a-dimethylolbutanoic acid. Preferred diamine carboxylate salts are the addition product of ethylenediamine to acrylic acid, mainly Sodium N-(2-aminoethyl)-[3-alaninate (commercially available as sodium salt under the trade name Disponil® PUD from BASF SE) and lysine. More preferably, the dihydroxy alkanoic acid(s) is a,a-dimethylolpropionic acid. Most preferably the acidic group is a sulfonic acid group. Preferably, component (A2) contains at least one salt group of a sulfonic acid group and an alkali metal ion, which salt group is capable to render the polyurethane dispersible in water. Examples include the adduct of sodium bisulfite onto but-2-ene-1 ,4-diol, so called polyethersulfonate, which is the propoxylated adduct of unsaturated diols like but-2-ene-1,4-diol and an alkali bisulfite component, described, for example, in US 4, 108, 814 formula (I, II and III, with II being preferred, especially preferred as sodium salt) and 2-(2-aminoethylamino)ethanesulfonic acid, also preferably in the form of its sodium salt.

In an embodiment of the invention, component (A2) comprises or essentially consists of or consists of at least one diamine sulfonate salt. In this embodiment, usually an isocyanate- terminated polyurethane pre-polymer is first formed by the reaction of components (A1) and (A3) which is then further reacted with the diamine sulfonate salt (A2) and optionally component (A4). A preferred diamine sulfonate salt is the sodium salt of 2-[(2- aminoethyl)amino]ethanesulfonic acid (CAS: 34730-59-1).

Component (A3)

At least one isocyanate-reactive polyol other than (A2) is used as component (A3). The amount of (A3) is preferably in the range from 74.5 to 94.5 wt.%, more preferably in the range from 81.5 to 92.8 wt.%, more preferably in the range from 84 to 91.2 wt.%, relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated.

Component (A3) preferably comprises at least 50 wt.%, more preferably at least 60 wt.%, even more preferably at least 70 wt.%, even more preferably at least 80 wt.%, most preferably at least 90 wt.% of an aliphatic polyester polyol with a hydroxy value of at most 112 mg KOH/g, preferably of at most 75 mg KOH/g, more preferably of at most 64 mg KOH/g, most preferably of at most 56 mg KOH/g, wherein the aliphatic polyester polyol is preferably obtained from (i) one or more diacids selected from the group consisting of succinic acid, methylsuccinic acid, glutaric acid, adipic acid and maleic acid, and (ii) one or more diols selected from the group consisting of propane-1 , 3-diol, butane-1,4-diol, hexane- 1 ,6-diol, epsilon-caprolactone and neopentyl glycol, more preferably the aliphatic polyester polyol is obtained from (i) one or more diacids selected from the group consisting of succinic acid, methylsuccinic acid, glutaric acid, adipic acid and maleic acid and (ii) one or more diols selected from the group consisting of propane-1, 3-diol, butane-1,4-diol and hexane-1,6-diol, even more preferably the aliphatic polyester polyol is obtained from (i) adipic acid and (ii) butane-1,4-diol and/or hexane-1,6-diol, even more preferably the aliphatic polyester polyol is obtained from adipic acid and butane-1 ,4-diol. The aliphatic polyester polyol is preferably an aliphatic polyester diol.

If the crystalline or semi-crystalline polyester polyols with a hydroxy value of at most 112 mg KOH/g and a melting temperature of at least 35 °C have an enthalpy of fusion of at least 50 J/g, the polyurethane-vinyl polymer prepared using the same shall normally have an enthalpy of fusion of equal or higher than 15 J/g. If desired, an adjustment of the enthalpy of fusion of the polyurethane-vinyl polymer can be achieved by a slight change in the content of polyester polyol in the composition or by a slight variation in the enthalpy of fusion of the polyester polyol. These measures require only exploratory experiments and are entirely within the practical experience of the average person skilled in the field. The production of polyester polyols is known from the prior art. The melting temperature of crystalline or semicrystalline polyester polyols is usually at least 35 °C, preferably in the range from 40 to 80 °C, especially preferably in the range from 42 to 60 °C.

Component (A3) may further comprise one or more polyols with a hydroxy value higher than 112 mg KOH/g, such as for example neopentyl glycol, butane diol and cyclohexanedimethanol.

The amount of component (A3) is preferably in the range from 74.5 to 94.5 wt.%, more preferably in the range from 81.5 to 92.8 wt.%, even more preferably in the range from 84 to 91.2 wt.%, relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated.

As used herein, the hydroxy value is determined with the method described further herein.

Component (A4)

Component (A4) is preferably used for preparing the polyurethane. At least one aminofunctional isocyanate reactive compound other than (A2) is used as component (A4). Examples are monoamines, diamines and polyamines.

Examples of monoamines are aliphatic and/or alicyclic primary and/or secondary monoamines such as ethylamine, diethylamine, the isomeric propyl- and butylamines, higher linear aliphatic monoamines and cycloaliphatic monoamines such as cyclohexylamine.

Further examples are aminoalcohols, i.e. compounds containing amino and hydroxyl groups in one molecule, such as for example ethanolamine, N-methylethanolamine, diethanolamine or 2-propanolamine.

Examples of diamines are ethane-1,2-diamine, hexamethylene-1,6-diamine, 1-amino-3,3,5- trimethyl-5-aminomethylcyclohexane (isophoronediamine), piperazine, hydrazine, 1,4- diaminocyclohexane and bis(4-aminocyclohexyl)methane. Further examples are aminoalcohols, i.e. compounds containing amino and hydroxyl groups in one molecule, such as for example 1,3-diamino-2-propanol, N-(2-hydroxyethyl)ethylenediamine or N,N-bis(2- hydroxyethyl)ethylenediamine

Examples of polyamines are diethylenetriamine and triethylenetetramine.

In a preferred form of the invention, the polymer according to the invention contains, for adjusting the molar mass, at least one monoamine and/or at least one diamine as aminofunctional isocyanate reactive compound (A4).

The amount of component (A4) is in the range from 0 to 2 wt.%, preferably in the range from 0.1 to 1 wt.%, relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated.

The polyurethane is preferably obtained by the reaction of components (A1), (A2), (A3) and optionally (A4). In a preferred form of the invention, the polyurethane is the reaction product of from 5 to 20 wt.% of component (A1), from 0.5 to 3.5 wt.% of component (A2), from 74.5 to 94.5 wt.% of component (A3), and from 0 to 2 wt.% of component (A4), wherein the amounts of (A1), (A2), (A3) and (A4) add up to 100 wt.%. In a more preferred form of the invention, the polyurethane is the reaction product of from 6.5 to 15 wt.% of component (A1), from 0.6 to 2.5 wt.% of component (A2), from 81.5 to 92.8 wt.% of component (A3), and from 0.1 to 1 wt.% of component (A4), wherein the amounts of (A1), (A2), (A3) and (A4) add up to 100 wt.%. In a particularly preferred form of the invention, the polyurethane is the reaction product of from 8 to 13 wt.% of component (A1), from 0.7 to 2.0 wt.% of component (A2), from 84 to 91.2 wt.% of component (A3), and from 0.1 to 1 wt.% of component (A4), wherein the amounts of (A1), (A2), (A3) and (A4) add up to 100 wt.%.

The polyurethane-vinyl polymer preferably comprises reacted hexamethylene diisocyanate and/or reacted 1,5-pentamethylene diisocyanate in an amount in the range from 1 to 15 wt.%, preferably in the range from 1 to 12 wt.%, more preferably in the range from 1.5 to 10 wt.%, most preferably in the range from 2 to 8 wt.%, relative to the polyurethane-vinyl polymer.

The polyurethane-vinyl polymer preferably has an acid value in the range from 0.6 to 20 mg KOH/g, more preferably in the range from 0.6 to 10 mg KOH/g, even more preferably in the range from 0.7 to 7 mg KOH/g, even more preferably in the range from 0.7 to 4 mg KOH/g, most preferably in the range from 0.8 to 3 mg KOH/g, especially preferred in the range from 0.8 to 2.7 mg KOH/g. As used herein, the acid value is calculated.

The polyurethane-vinyl polymer preferably has a hydroxy value in the range from 1 to 50 mg KOH/g, more preferably in the range from 1 to 40 mg KOH/g, even more preferably in the range from 1.5 to 35 mg KOH/g, even more preferably in the range from 2 to 30 mg KOH/g. As used herein, the hydroxy value of a component is measured by titration a known mass of component according to ASTM D4274 and is expressed as mg KOH/g.

The weight average molecular weight Mw of the polyurethane-vinyl polymer is preferably at least 10 kDalton, more preferably at least 20 kDalton, most preferably at least 40 kDalton, preferably at most 800 kDalton, more preferably at most 650 kDalton, most preferably at most 500 kDalton. As used herein, the weight average molecular weight is determined with the method as described further herein.

The z-average particle size of the dispersed particles present in the waterborne adhesive composition according to the invention is preferably in the range from 30 to 600 nm, more preferably in the range from 50 to 400 nm, even more preferably in the range from 70 to 350 nm, most preferably in the range from 110 to 275 nm, wherein the z-average particle size is determined with the method as described further herein.

The polydispersity (Mw/Mn) of the dispersed particles present in the waterborne adhesive composition according to the invention is preferably in the range from 9 to 50, more preferably in the range from 10 to 40, even more preferably in the range from 10 to 35, wherein the polydispersity is determined with the method as described further herein. The polyurethane and the vinyl polymer are preferably present in the dispersion in a total amount in the range from 40 to 70 wt.%, more preferably in the range from 40 to 60 wt.%, more preferably in the range from 40 to 55 wt.%, relative to the total weight of the dispersion.

In a preferred embodiment of the invention, the polyurethane-vinyl polymer comprises from 1 to 15 wt.% of reacted hexamethylene diisocyanate and/or reacted1,5-pentanediisocyanate, whereby the amount of reacted hexamethylene diisocyanate and/or reacted 1 ,5- pentanediisocyanate is given relative to the total amount of components used to prepare the polyurethane-vinyl polymer from which the building blocks from the polyurethane-vinyl polymer are emanated; component A3 comprises at least 50 wt.% of an aliphatic polyester polyol with a hydroxy value of at most 112 mg KOH/g that is preferably obtained from (i) succinic acid, methylsuccinic acid, glutaric acid, adipic acid and/or maleic acid, and (ii) propane-1, 3-diol, butane-1,4-diol, hexane-1 ,6-diol, epsilon-caprolactone and/or neopentyl glycol; the acid value of the polyurethane-vinyl polymer is in the range from 0.6 to 20 mg KOH/g; and the polyurethane-vinyl polymer particles have a z-average particle size in the range from 30 to 600 nm.

In another preferred embodiment of the invention, the polyurethane-vinyl polymer comprises from 1 to 15 wt.% of reacted hexamethylene diisocyanate and/or reacted 1,5- pentanediisocyanate, whereby the amount of reacted hexamethylene diisocyanate and/or reacted 1,5-pentanediisocyanate is given relative to the total amount of components used to prepare the polyurethane-vinyl polymer from which the building blocks from the polyurethane-vinyl polymer are emanated; component A3 comprises at least 50 wt.% of an aliphatic polyester polyol with a hydroxy value of at most 112 mg KOH/g that is preferably obtained from (i) succinic acid, methylsuccinic acid, glutaric acid, adipic acid and/or maleic acid, and (ii) propane-1, 3-diol, butane-1 ,4-diol, hexane-1,6-diol, epsilon-caprolactone and/or neopentyl glycol; the acid value of the polyurethane-vinyl polymer is in the range from 0.6 to 20 mg KOH/g; the hydroxy value of the polyurethane-vinyl polymer is in the range of 0.5 to 20 mg KOH/g and the polyurethane-vinyl polymer particles have a z-average particle size in the range from 30 to 600 nm.

The present invention further relates to a process for preparing the waterborne dispersion according to the present invention. The process preferably comprises preparing an aqueous dispersion of the polyurethane; vinyl monomer is added before, during or after preparation of the polyurethane; and a free radical initiator is added to polymerize the vinyl monomer in the presence of the polyurethane. In the preferred embodiment of the invention in which component (A2) comprises or essentially consists of or consists of at least one diamine sulfonate salt, the process for preparing the aqueous adhesive composition according to the invention preferably comprises at least the following steps:

1) Preparing a polyurethane pre-polymer by reacting (A1) and (A3).

2) Preparing a polyurethane by reacting the polyurethane pre-polymer with (A2) and (A4),

3) Preparing an aqueous dispersion of the polyurethane by adding water to the polyurethane obtained in step 2) and/or adding the polyurethane obtained in step 2) to water,

4) Adding one or more vinyl monomers during and/or after step 3), and

5) Preparing a vinyl polymer by polymerizing the one or more vinyl monomers in the presence of the polyurethane, thereby obtaining the polyurethane-vinyl polymer hybrid.

Step 1) and/or step 2) is preferably carried out in the presence of a water-miscible organic solvent, preferably acetone and/or methyl ethyl ketone, more preferably acetone. The water- miscible organic solvent is preferably at least partly removed after or during step 3). The vinyl monomer(s) are preferably added after step 3).

The amount of water-miscible organic solvent added in the process is preferably at least 30 wt.%, preferably at least 40 wt.%, more preferably at least 50 wt.%, relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated.

The waterborne dispersion according to the present invention preferably has a solids content of at least 15 wt.%, more preferably of at least 20 wt.%, more preferably of at least 25 wt.%, more preferably of at least 30 wt.%, more preferably of at least 35 wt.%, more preferably of at least 40 wt.%, most preferably of at least 45 wt.% and preferably of at most 70 wt.%, more preferably of at most 65 wt.%, even more preferably of at most 60 wt.% or of at most 55 wt.%.

In particular, the dispersions of the invention are suitable as adhesives or as binders for adhesives, particular preference being given to laminating adhesives. A distinction should be made between the 1K (one-component) and 2K (two-component) systems. The aqueous adhesive compositions are suitable both as 1K or 2K systems. 1K systems may comprise a crosslinker and are stable on storage. In the case of 2K systems, the crosslinker is not added until shortly before use. The adhesive dispersions may also be free from compounds which undergo crosslinking reaction with the polyurethane. In that case the polyurethane dispersions of the invention may be used preferably as one-component (1K) adhesives, more particularly 1K laminating adhesives. Preferred crosslinkers are polyisocyanates, carbodiimides, and aziridines. Particularly preferred are polyisocyanates having a least two isocyanate groups per molecule. The polyisocyanate compounds are usually used in an amount of from 0.1 to 20 wt.%, preferably from 0.5 to 10 wt.%, particularly preferably from 1.5 to 6 wt.%, based on the aqueous adhesive composition.

The present invention also provides adhesive systems comprising, consisting essentially of, or consisting of an aqueous dispersion according to the invention. The aqueous dispersions according to the invention can be employed by themselves, or with binders, auxiliary substances and additives known in coatings and adhesives technology can be used. The aqueous adhesive composition therefore optionally include a variety of other additives including, e.g., other polymers, catalysts (e.g. amine based), preservatives, pH modifiers (e.g. aqueous ammonia), adhesion promoters (e.g., silane containing compounds), tackifiers (e.g., ground tackifiers), pigments, surfactants, antifoaming agents, defoaming agents, fungicides, bactericides, thickening agents, blocking agents and stabilizers (e.g. amines), fillers (e.g. carbonates, talc, starch), materials that help the adhesive film to form a barrier (e.g. nano materials (e.g. mineral fillers, glass microbubbles)), rheology modifiers, salts, and ground powders, electrically conductive materials (e.g. silver), and any combination thereof.

Accordingly, the present invention further relates to a waterborne adhesive composition comprising, consisting essentially of, or consisting of the dispersion as described herein above. The polyurethane and the vinyl polymer are preferably present in the waterborne adhesive composition in a total amount of at least 65 wt.%, more preferably of at least 70 wt.%, more preferably of at least 75 wt.%, more preferably of at least 80 wt.%, more preferably of at least 85 wt.%, more preferably of at least 90 wt.%, more preferably of at least 95 wt.%, more preferably of at least 99 wt.% or in a total amount of 100 wt.%, relative to the solids content of the waterborne adhesive composition.

The adhesive compositions comprising the dispersions according to the invention are suitable for bonding any desired substrates, such as, for example, paper, cardboard, wood, textiles, metal, plastic, wood composite e.g. MDF boards and panel boards, cork, leather or mineral materials as well as any of the aforementioned substrates which are coated or otherwise surface treated. The adhesive compositions of the invention are also suitable as laminating adhesive for the surface enhancement of a solid support with a foil, generally speaking polymer foils or paper, particularly decorative paper coated or impregnated with a polymer, or leather, are bonded to articles made of wood or to metal or plastic. For example, furniture parts are laminated with paper or polymer foils, or interior automotive components are laminated with polymer foils made from PVC. The adhesive compositions according to the invention are also in particular suitable for the bonding of rubber materials, such as, for example, natural and synthetic rubbers, various plastics materials such as polyurethanes, polyvinyl acetate, polyvinyl chloride, in particular plasticized polyvinyl chloride. They are particularly preferably used for bonding soles made of these materials, preferably based on polyvinyl chloride, particularly preferably plasticized polyvinyl chloride, or based on polyethylvinyl acetate or polyurethane elastomeric foam, to shoe shafts of leather or synthetic leather as well as textile laminates with PVC, polyurethanes or polyolefines. The adhesive compositions according to the invention are also particularly suitable for bonding films based on (plasticized) polyvinyl chloride or for bonding a film based on (plasticized) polyvinyl chloride to for example ABS or treated fibre filled PP or for bonding (plasticized) polyvinyl chloride to wood, for example beech wood, or wood composite.

The present invention further relates to a two-component adhesive composition (2K-system) for the adhesive bonding of one or more substrates, wherein the two-component adhesive composition consists of a first component and a second component, wherein the first component comprises, consists essentially of, or consists of the waterborne adhesive composition as described herein above; and the second component comprises a crosslinker.

The present invention further relates to an adhesive film obtained from the adhesive composition as described herein above.

The present invention further relates to the use of the adhesive composition as described herein above for adhesive bonding of one or more substrates by the heat-activation method. In the heat activation method, the waterborne adhesive composition is applied on at least a part of at least one of the surfaces of the substrate or of the substrates to be adhesively bonded; after completion of evaporation or during evaporation of the water, the adhesive layer thus obtained is activated by heating to at least the activation temperature of the adhesive layer, preferably to above the melting temperature of the crystalline phase present in the polyurethane-vinyl polymer, more preferably to above the melting temperature of the polyurethane-vinyl polymer; and joining the one or more substrates. The adhesive layer can be applied in or more layers with or without intermediate drying step. In a preferred embodiment the adhesive composition is applied by spray, brush, curtain, dipping, knife coating, slot dye, printing processes like digital printing, screen printing, roller coating and I or gravure printing process, with brushing and spraying being most preferred. The present invention further relates to a process for adhesively bonding of one or more substrates, wherein the process comprises the following steps:

(1) Applying the adhesive composition as described herein above on at least a part of at least one of the surfaces of the substrate or of the substrates to be adhesively bonded to obtain a liquid coating (1a),

(2) Optionally evaporating at least part of the water present in the liquid coating (1a) to obtain an at least partially dried coating (2a), and

(3) Activating the liquid coating (1a) (in case step (2) is not applied) or the at least partially dried coating (2a) respectively (in case step (2) is applied) by heating to at least the activation temperature of the liquid coating (1a) or of the at least partially dried coating (2a) respectively to convert the liquid coating (1a) or the at least partially dried coating (2a) into an adhesive state, preferably to a temperature above the melting temperature of the polyurethane-vinyl polymer, and

(4) Joining the one or more substrates.

Step (1) can be accomplished by known methods in coating and adhesives technology e.g. by spray, brush, curtain, dipping, knife coating, slot dye, printing processes like digital printing, screen printing, roller coating and I or gravure printing process, with brushing and spraying being most preferred.

Step (2 and 3) can be accomplished by known methods in coating and adhesives technology e.g. by using ovens with heat, IR light, microwave radiation, convecting air/gas flow.

Preferably, the process comprises the following steps:

(2) Evaporating of the water present in the liquid coating (1a) to obtain a dry coating (2a), and

(3) Activating the dry coating (2a) by heating to at least the activation temperature of the dry coating (2a) into an adhesive state, preferably to a temperature above the melting temperature of the polyurethane-vinyl polymer, and

(4) Joining the one or more substrates.

The present invention is now illustrated by reference to the following examples. Unless otherwise specified, all parts, percentages and ratios are on a weight basis. Components and abbreviations used:

Polyester I: polyester diol formed from butane-1 ,4-diol and adipic acid having an OH number=50 mg KOH/g

Desmodur® H: hexamethylene 1 ,6-diisocyanate (Covestro Deutschland AG, Leverkusen/Germany)

Desmodur® I: isophorone diisocyanate (Covestro Deutschland AG, Leverkusen/Germany)

Lankropol® KO2: sodium di-octyl sulphosuccinate in ethanol/water (Nouryon)

MMA: methylmethacrylate

BA: n-butylacrylate

HEMA: hydroxy-ethyl methacrylate

The following methods and test methods were used here:

Determination of glass transition temperatures, melting temperatures and melting enthalpies by means of Differential Scanning Calorimetry (DSC):

The glass transition temperatures, melting temperatures and melting enthalpies were determined using Differential Scanning Calorimetry (DSC) with a DSC Q2000 calorimeter from TA Instruments.

The determination was carried out in accordance with DIN EN ISO 11357-1 :2017 (2017-02) - Plastics - Dynamic differential thermal analysis (DSC) - Part 1: General principles (ISO 11357-1 :2016); German version EN ISO 11357-1:2016 and the standard parts

DIN EN ISO 11357-2:2020-08 - Plastics - Differential scanning calorimetry (DSC) - Part 2: Determination of glass transition temperature and glass transition step height (ISO 11357- 2:2020); German version EN ISO 11357-2:2020

DIN EN ISO 11357-3:2018-07 - Plastics — Differential dynamic thermal analysis (DSC) — Part 3: Determination of melting and crystallization temperature and enthalpy of melting and crystallization (ISO 11357-3:2018).

Sample preparation for aqueous dispersions

A film was prepared by applying the dispersion with 100 pm wet film thickness on a glass plate using a doctor blade, pre-dried for 2 hours at 23°C and 50% relative humidity, the coated glass plate was then transferred to a drying box and stored there for 3 days at 23°C and 0% relative humidity. The coated glass plate was removed from the drying box, coating was scraped from the glass plate and approx. 5 mg of this sample material is used for the DSC measurement. The following measurement program was carried out:

Rapid cooling to the starting temperature -100 °C, then start of three heats from -100 °C to +150 °C with a heating rate of 20 K/min and the maximum cooling rate under nitrogen atmosphere and cooling with liquid nitrogen.

Determination of glass transition temperatures

The glass transition temperatures (Tg) were determined in accordance with DIN EN ISO 11357-2:2020-08

The glass temperature corresponds to the temperature at half the height of the glass transition, whereby the third heating was evaluated. If no glass transition temperature can be determined, the measuring program was changed as follows. Rapid cooling to the starting temperature -140 °C, then start of three heats from -140 °C to +150 °C with a heating rate of 20 K/min and the maximum cooling rate of under nitrogen atmosphere and cooling with liquid nitrogen.

Determination of melting temperatures

The first heating was used to determine the melting temperatures, the specified melting temperatures correspond to the peak crystallization temperatures.

Determination of the enthalpies of melting

To determine the enthalpies of melting, the first heating was used. In the case of multiple melt peaks, the melt enthalpies of all melt peaks were added with a peak melting temperature Tp,m in the range of 15 to 80 °C. Peaks with melt fractions of < 0.9 J/g were not considered.

Hydroxy value

The hydroxy value of a component was measured by titration a known mass of component according to ASTM D4274 and is expressed as mg KOH/g.

Acid value of the hybrid

The acid value of the polyurethane-vinyl polymer hybrid (mg KOH/g hybrid) refers to the amount of acid groups present in the polyurethane-vinyl polymer hybrid and was calculated as follows:

Molar amount of acid groups present in 1 g solid polyurethane-vinyl polymer x 56100, i.e. the product obtained by multiplying the molar amount of acid groups present in 1 g solid polyurethane-vinyl polymer by 56100. Average particle size PS:

The intensity average particle size, z-average, has been determined by photon correlation spectroscopy using a Malvern Zetasizer Nano ZS. Samples were diluted in demineralized water to a concentration of approximately 0.1 g dispersion/liter. Measurement temperature 25°C. Angle of laser light incidence 173°. Laser wavelength 633 nm.

£H

The pH was measured using a Metrohm pH meter.

Solids

The solid content of the dispersion was measured on a HB43-S halogen moisture analyzer from Mettler Toledo at a temperature of 75°C.

Viscosity

The viscosity was determined with a Brookfield DV-I viscometer (spindle S61 , 60 rpm, 23°C).

Size exclusion chromatography in NMP

The number average molecular weight M_n, weight average molecular weight M_w and molecular weight distribution was determined with Size exclusion chromatography (SEC), using three PLgel 10 pm Mixed-B columns at 70°C on a Waters Alliance e2695 LC system with a Waters 2414 DRI detector. N-Methylpyrrolidone (NMP) and 10 mM lithiumbromide (LiBr) was used as eluent with a flow of 1 mL/min. The samples were dissolved in the eluent using a concentration of 5 mg polymer per mL solvent. The solubility was assessed with a laser pen after 24 hours stabilization at room temperature; if any scattering was visible the samples were filtered first and 100 pl sample solution was injected. The MMD (molecular mass distribution) results were calculated with 12 narrow polystyrene standards from 370 to 1.071.000 Da.

In general, a series of average molecular weights can be defined by the eguation: M= SN_iMⁿ⁺¹/SN_iM_i ⁿ, whereby: n=0 gives M= M_n; n = 1 gives M = M_w, n = 2 gives M = M_z .The higher averages are increasingly more sensitive to high molecular weight polymers. Nj is the number of molecules with molecular weight Mj.

2k Softening Point on plasticized PVC

The 2K adhesive was applied by brush on two test specimens (20 mm x 50 mm) made from plasticized PVC (30% plasticizer by weight) supplied by Rocholl. The bonding area was 20 mm x 10 mm and the adhesive was dried 60 minutes at 23°C/50% rel. humidity. After this time the adhesive was heat activated for 10 sec. by the using IR lamps (Funck Schockaktiviergerat 2000) to a surface temperature of 86°C. Immediately afterwards the two test specimen were joined together (overlapping bonding area: 20 mm x 10 mm) and pressed 1 minute at 4 bar pressure. After storing 3 days at 23°C/50% rel. humidity the bonded test specimen were loaded with 4kg weight (lap-shear-Test) and then heated in a heating chamber for 30 minutes at 40°C afterwards the temperature was continuously increased by a heating rate of 0.5K/min. until the bonded specimens were fully separated. The temperature at time of the separation (failure of bond) was noted (unit of measurement °C) as the so called “Softening Point”. Results are given in table 3.

2k Heat Resistance on beech wood/hard PVC

The 2K adhesive was applied two times by brush on beech wood specimens (50 mm x 140 mm x 4 mm). The bonding area was 50 mm x 110 mm and the adhesive was dried for 30 minutes (after first adhesive coating) and then 60 minutes (after second adhesive coating) at 23°C/50% rel. humidity. Immediately after drying a hard-PVC furniture lamination foil (0.35 mm 150 mm x 280 mm) was joined on top of the beech wood specimen and heat laminated with a heated press (103°C) for 10 sec. at 4 bar pressure with 90°C bondline temperature. After storing for 3 days at 23°C/50% rel. humidity the bonded test specimen were loaded with 0.5kg weight (180° peel-test) and then heated in a heating chamber for 1 hour at 50°C, afterwards the temperature was increased by 10°C each hour until 120°C was reached or the bonded specimens were fully separated, whatever came first. The temperature at time of the separation was noted as the so called “Heat Resistance” (unit of measurement °C). Results are given in table 3.

1 k/2k adhesion bond strength on plasticized PVC (soft-PVC)

The adhesive was applied by brush on two strips of plasticized PVC (30% plasticizer by weight), supplied by Rocholl (30 mm x 200 mm). The bonding area was 30 mm x 150 mm and the adhesive was dried 60 minutes at 23°C/50% rel. humidity. After drying the adhesive was heat activated 10 sec. by the using of IR lamps (Funck Schockaktiviergerat 2000) to a surface temperature of 86°C. Immediately afterwards the two test specimen were joined together and pressed for 1 minute at 4 bar pressure. The bond strength (unit of measurement: N/mm) for separating the two PVC strips was determined in a T-Peel-Test (90 degree at start) with a tensile tester (100 mm/min tensile speed) after storing for 3 days at 23°C/50% rel. humidity. Results are given in table 3. 1k bond strength soft PVC to soft PVC when 1k adhesives are used, 2k bond strength soft PVC to soft PVC when 2k adhesives were used.

2k adhesion bond strength on beech wood/hard PVC

The 2K adhesive was applied two times by brush on beech wood specimens (30 mm x 120 mm x 4 mm). The bonding area was 30 mm x 90 mm and the adhesive was dried 30 minutes (first adhesive coating) and then 60 minutes (second adhesive coating) at 23°C/50% rel. humidity. Immediately after drying a hard-PVC furniture lamination foil (0.35 mm/50 mm x 280 mm) was joined on top of the beech wood specimen and heat laminated with a heated press (103°C) 10 sec. at 4 bar pressure with 90°C bondline temperature. The bond strength (unit of measurement: N/mm) for separating the PVC foil was determined in an 180° angle with a tensile tester (100 mm/min tensile speed) after storing for 3 days at 23°C/50% rel. humidity. Results are given in table 3. 1k bond strength hard-PVC when 1k adhesives are used, 2k bond strength when 2k adhesives were used.

Preparation of aqueous polyurethane dispersion PUD A

450 g of polyester I was kept for 1 hour at 110 degrees centigrade and 15 mbar. At 80 degrees centigrade, 30.11 g of Desmodur® H and then 20.14 g of Desmodur® I were added. The mixture was stirred at 80 to 90 degrees centigrade until a constant isocyanate content of 1.15 percent has been reached. The reaction mixture was dissolved in 750 g of acetone and cooled to 48 degrees centigrade Into the homogeneous solution was added a solution of 5.95 g of the sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid and 2.57 g of diethanolamine in 65 g of water with vigorous stirring. After 30 minutes, the mixture was dispersed by addition of 700 g of water. Distillative removal of the acetone afforded an aqueous polyurethane-polyurea dispersion having a solids content of 40.0 percent by weight.

The polymer present was semicrystalline after drying with a glass transition at a glass transition temperature Tg of -54 degrees centigrade, a melting temperature of 48 degrees centigrade and an enthalpy of fusion of 50.4 J/g.

Preparation of aqueous vinyl polymer emulsion B

A 2000 cm3 flask equipped with a thermometer and overhead stirrer was charged with water (1041.5 g), Lankropol® KO2 (7.25 g) and ammonium persulphate (1.95 g) and heated to 88°C under a nitrogen atmosphere. At 88°C a mixture of MAA (39.6 g), BA (553.7 g) and MMA (197.8 g) was added over a period of 60 minutes. Together with this mixture a mixture of a mixture of water (100 g), ammonium persulphate (2.0 g) was added over a period of 70 minutes. At the end of the feed, the reaction was stirred at 90°C for 15 minutes. After 15 minutes at 90°C, the reaction mixture was cooled to room temperature and the pH was adjusted to 8, 5-9,0 with an aqueous KOH solution (12.5% in water). Proxel Ultra 10 (6 g) was added and the batch was filtered through a filter cloth to remove any coagulum formed during the reaction. Solids: 39.2%; pH: 9. Preparation of aqueous vinyl polymer emulsion C

A 2000 cm3 flask equipped with a thermometer and overhead stirrer was charged with water (1041.5 g), Lankropol® KO2 (7.25 g) and ammonium persulphate (1.95 g) and heated to 88°C under a nitrogen atmosphere. At 88°C a mixture of MAA (39.6 g), BA (435.1 g) and MMA (316.4 g) was added over a period of 60 minutes. Together with this mixture a mixture of a mixture of water (100 g), ammonium persulphate (2.0 g) was added over a period of 70 minutes. At the end of the feed, the reaction was stirred at 90°C for 15 minutes. After 15 minutes at 90°C, the reaction mixture was cooled to room temperature and the pH was adjusted to 8, 5-9,0 with an aqueous KOH solution (12.5% in water). Proxel Ultra 10 (6 g) was added and the batch was filtered through a filter cloth to remove any coagulum formed during the reaction. Solids: 38.6%; pH: 8.9.

Preparation of aqueous vinyl polymer emulsion D

A 2000 cm3 flask equipped with a thermometer and overhead stirrer was charged with water (1041.5 g), Lankropol® KO2 (7.25 g) and ammonium persulphate (1.95 g) and heated to 88°C under a nitrogen atmosphere. At 88°C a mixture of MAA (39.6 g), BA (332.2 g) and MMA (419.3 g) was added over a period of 60 minutes. Together with this mixture a mixture of a mixture of water (100 g), ammonium persulphate (2.0 g) was added over a period of 70 minutes. At the end of the feed, the reaction was stirred at 90°C for 15 minutes. After 15 minutes at 90°C, the reaction mixture was cooled to room temperature and the pH was adjusted to 8, 5-9,0 with an aqueous KOH solution (12.5% in water). Proxel Ultra 10 (6 g) was added and the batch was filtered through a filter cloth to remove any coagulum formed during the reaction. Solids: 38.1%; pH: 8.8.

Comparative Examples C2 to C4

A blend of polyurethane dispersion A with respectively aqueous vinyl polymer emulsion B (C2), aqueous vinyl polymer emulsion C (C3) and aqueous vinyl polymer emulsion C (C4) was prepared, able 1 specifies the components and its amounts applied for preparing the blends of polyurethane and vinyl polymer resin dispersions according to comparative examples C2 to C4. Unless specified otherwise, the amounts of the different components are expressed in grams.

Examples 1-5 and Comparative Experiments C1-C5

Example 1 : Preparation of polyurethane-urea-vinyl polymer hybrid dispersion (65/35 T g acrylic phase=20) In a 3 liter flask 913.2 gram of the polyurethane dispersion A was mixed under continuous stirring with 117.2 g MMA and 78 g BA and 217.8 g water under nitrogen atmosphere. After 60 minutes a mixture of tBHPO (1.39 g (70% in water)) and FeEDTA (0.98 g (1% solution in water)) and 3 gr of deionized water was added. Subsequently, a solution of iAA acid in water (1%, 58.9 g) neutralized with ammonia just above pH 8, was slowly fed to the Pll dispersion via a dropping funnel over a period of 45 minutes. The resulting polyurethane-vinyl polymer hybrid dispersion had a solid content of 40 wt% solids and a pH of 7.3 and a viscosity of 27 mPa.s. The molecular weight was determined by size exclusion chromatography as described herein above and the Mw was 198 kDalton and the polydispersity (=Mw/Mn) was 22.3.

The acid value of the polyurethane-vinyl polymer hybrid was calculated as follows:

1. Determining weight % of acid groups present in the polyurethane prepared in PUD A,

1.e., weight % of AAS present in the polyurethane prepared in PUD A: (5.95x100)/(450+30.11 +20.14+5.95+2.57)=1.17 wt% s/s.

2. Determining weight amount (gram) of solid polyurethane-urea-vinyl polymer hybrid (65/35 Tg acrylic phase=20) prepared in example 1:

2.1. Determining weight amount of solid PU prepared in PUD A:

913.2 g of the PU dispersion with 40.0 % solids content is used in example 1, i.e., = 0.4 x 913.2 = 365.3 gram of solid PU.

2.2. Determining weight amount of solid polyurethane-urea-vinyl polymer hybrid prepared in example 1 is the sum of the weight amount of solid PU prepared in PUD A and the weight amount of the vinyl monomers added in example 1 , i.e.,

[365.3 g (solid PU) + 117.2 g (MMA) + 78 g (BA)] = 560.5 g of solid polyurethane-urea-vinyl polymer hybrid.

3. Determining amount of acid groups present in the polyurethane prepared in PUD A and used in example 1 : (1.17/100) x 365.3 = 4.27 g.

Thus, the solid PU prepared in PUD A and used in example 1 contains 4.27 grams of acid groups and consequently also the resulting polyurethane-vinyl polymer hybrid prepared in example 1 contains 4.27 grams of acid groups. 4. Determining the acid value of the polyurethane-vinyl polymer hybrid prepared in example 1 :

Molar mass AAS = 190.2 g/mol,

[(4.27 /190.2)/ 560.5] x 56100 = 2.3 mg KOH/g.

Examples 2-6 and Comparative Examples C4 and C5

Example 1 was repeated but with the components and amounts as specified in Table 1.

Table 1 specifies the components and its amounts applied for preparing the polyurethane- vinyl polymer hybrid dispersions according to examples 1 to 6 and comparative examples C4 to C5. Unless specified otherwise, the amounts of the different components are expressed in grams.

Table 1: Compositions of UA Ex. 1 to 6

Table 1. Continued: Compositions of Comparative Examples C1 to C5

The specifications of the resulting polyurethane-vinyl polymer hybrids are illustrated in Table 2. Table 2: Specifications of UA Ex.1 to 6

Table 2 continued: Comparative Examples C1 to C5

Preparation of adhesive formulations

Preparation of 1k adhesives

The inventive or comparison dispersions (100g) were mixed with 1g of a mixture of Borchigel® L 75 N (non-ionic polyurethane-based medium shear rate thickener for water- based coatings systems, Borchigel® L 75 N containing 50% water by weight) prepared by mixing 40 g of Borchigel® L 75 N with 60 g of water. The mixing was done with a magnetic stirrer in a plastic beaker.

Preparation of 2k adhesives

The inventive or comparative dispersions (100 g) were mixed with 1g of a mixture of Borchigel® L 75 N (non-ionic polyurethane-based medium shear rate thickener for waterbased coatings systems, Borchigel® L 75 N containing 50% water by weight) prepared by mixing 40 g of Borchigel® L 75 N with 60 g of water. The mixing was done with a magnetic stirrer in a plastic beaker. To this mixture 3,03 g of Desmodur® DN (Covestro, Hydrophilic aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI) were added. The formulations were used immediately after preparation within a time of maximal 60 minutes.

Table 3: Test results of the polyurethane-vinyl polymer hybrid dispersions and comparative examples

The invention is further defined by the following exemplary embodiments as listed hereafter. Any one of the embodiments, aspects and preferred features or ranges as disclosed in this application may be combined in any combination, unless otherwise stated herein or if technically not feasible to a skilled person. A first aspect of a first embodiment is a waterborne dispersion for use in an adhesive composition, wherein the dispersion comprises dispersed polymer particles comprising both (i) a polyurethane and (ii) a vinyl polymer, wherein said dispersed particles comprising the polyurethane and the vinyl polymer in a weight ratio of the polyurethane to the vinyl polymer higher than 1, and the polyurethane-vinyl polymer comprises a crystalline phase having a melting temperature in the range from 30 to 80 °C and an enthalpy of fusion of at least 15 J/g, whereby the melting temperature and the enthalpy of fusion are determined by differential scanning calorimetry according to DIN EN ISO 11357-1:2017 (2017-02) at a heating rate of 20 K/min.

Another aspect of the first embodiment is the composition of the first aspect, wherein the polyurethane and the vinyl polymer are present in said dispersed particles in a weight ratio of the polyurethane to the vinyl polymer lower than or equal to 9, preferably in a weight ratio of at most 8, even more preferably of at most 5, even more preferably of at most 4, even more preferably of at most 3, even more preferably of at most 2.5.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane and the vinyl polymer are present in the dispersed particles in a weight ratio of the polyurethane to the vinyl of at least 1.1 , preferably of at least 1.2.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the vinyl polymer has a glass transition temperature Tg and wherein the amount of the vinyl polymer in the polyurethane-vinyl polymer and the glass transition temperature Tg of the vinyl polymer are chosen such that the product obtained by multiplying the T_g (°C) of the vinyl polymer with the weight fraction of the vinyl polymer in the polyurethane-vinyl polymer is in the range from -30 to 50, preferably in the range from -15 to 40, more preferably in the range from -10 to 35, even more preferably in the range from -5 to 30, wherein the glass transition temperature is calculated using the Fox equation.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein at least 30 wt.%, more preferably at least 40 wt.%, more preferably at least 50 wt.%, even more preferably at least 60 wt.%, even more preferably at least 70 wt.% and even more preferably at least 80 wt.% of the total amount of vinyl monomer(s) used to prepare the at least one vinyl polymer is selected from the group consisting of methyl methacrylate, butyl acrylate, butyl methacrylate, ethyl hexyl acrylate, octyl acrylate (preferably 2-octyl acrylate), styrene and mixtures of two or more of said monomers.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein hydroxyl functional vinyl monomer(s) are used in an amount of from 1 to 20 wt.% or from 1 to 10 wt.% or from 2 to 8 wt.%, relative to the total amount of vinyl monomers.

Another aspect of the first embodiment is the composition of the previous aspect of the first embodiment, wherein the hydroxyl functional vinyl monomer(s) are hydroxy(C1 -C4)alkyl (meth) acrylates, preferably hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate and/or hydroxypropyl acrylate; more preferably the hydroxy-functional vinyl monomer is hydroxyethyl methacrylate (HEMA). Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the at least one vinyl polymer preferably comprises less than 0.1 wt.% of acrylonitirile, more preferably the vinyl polymer does not comprise acrylonitrile.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein said dispersed particles comprising the polyurethane and the vinyl polymer are obtained by free radical polymerization of at least one vinyl monomer in the presence of at least one water-dispersed polyurethane thereby obtaining a hybrid of polyurethane and vinyl polymer (polyurethane-vinyl polymer)).

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane-vinyl polymer after drying is semicrystalline or crystalline and has a melting temperature of at least 30 °C, preferably of at least 35 °C, more preferably of at least 40 °C, even more preferably of at least 42 °C and of at most 80 °C, preferably of at most 70 °C, more preferably of at most 55 °C.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane-vinyl polymer has an enthalpy of fusion of at least 15 J/g, preferably of at least 17 J/g, more preferably of at least 18 J/g, more preferably of at least 19 J/g, particularly preferably of at least 20 J/g.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane-vinyl polymer has an enthalpy of fusion of at most 100 J/g, preferably of at most 90 J/g, more preferably of at most 80 J/g, more preferably of at most 70 J/g.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane and the vinyl polymer are present in the dispersion in a total amount in the range from 40 to 70 wt.%, preferably in the range from 40 to 60 wt.%, more preferably in the range from 40 to 55 wt.%, relative to the total weight of the dispersion.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane is polyurethane-urea.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane is obtained by the reaction of at least the following components (A1)-(A3) and optionally (A4):

(A1) At least one polyisocyanate, (A2) At least one isocyanate-reactive compound that contains at least one salt group which is capable to render the polyurethane dispersible in water and/or at least one functional group that can be converted into a salt group which is capable to render the polyurethane dispersible in water,

(A3) At least one isocyanate-reactive polyol other than (A2), and

Another aspect of the first embodiment is the composition of the previous aspect of the first embodiment, wherein the polyurethane is the reaction product of: from 5 to 20 wt.%, preferably from 6.5 to 15 wt.%, more preferably from 8 to 13 wt.% of component (A1), from 0.5 to 3.5 wt.%, preferably from 0.6 to 2.5 wt.%, more preferably from 0.7 to 2.0 wt.% of component (A2), from 74.5 to 94.5 wt.%, preferably from 81.5 to 92.8 wt.%, more preferably from 84 to 91.2 wt.% of component (A3), and from 0 to 2 wt.%, preferably from 0.1 to 1 wt.% of component (A4), wherein the amounts of (A1), (A2), (A3) and (A4) add up to 100 wt.%.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein (A3) comprises at least 50 wt.%, more preferably at least 60 wt.%, even more preferably at least 70 wt.%, even more preferably at least 80 wt.%, most preferably at least 90 wt.% of an aliphatic polyester polyol with a hydroxy value of at most 112 mg KOH/g, preferably of at most 75 mg KOH/g, more preferably of at most 64 mg KOH/g, most preferably of at most 56 mg KOH/g, wherein the aliphatic polyester polyol is preferably obtained from (i) succinic acid, methylsuccinic acid, glutaric acid, adipic acid and/or maleic acid, and (ii) propane-1, 3-diol, butane-1,4-diol, hexane-1,6-diol, epsilon- caprolactone and/or neopentyl glycol, more preferably the aliphatic polyester polyol is obtained from (i) adipic acid and (ii) butane-1 ,4-diol and/or hexane-1,6-diol, even more preferably the aliphatic polyester polyol is obtained from adipic acid and butane-1,4-diol.

Another aspect of the first embodiment is the composition of the previous aspect of the first embodiment, wherein the aliphatic polyester polyol is an aliphatic polyester diol.

Another aspect of the first embodiment is the composition of any of the three previous aspects of the first embodiment, wherein the at least one polyisocyanate according to (A1) comprises 1,5-pentane diisocyanate (CAS number 4538-42-5) and/or hexamethylene diisocyanate (CAS number 822-06-0) and optionally isophorone diisocyanate (CAS number 4098-71-9) and/or dicyclohexylmethane-4,4’-diisocyanate H12MDI (CAS number 5124-30- 1).

Another aspect of the first embodiment is the composition of any of the four previous aspects of the first embodiment, wherein component (A2) comprises or essentially consists of or consists of at least one diamine sulfonate salt, preferably component (A2) comprises or essentially consists of or consists of the sodium salt of 2-[(2- aminoethyl)amino]ethanesulfonic acid (CAS: 34730-59-1).

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane comprises reacted hexamethylene diisocyanate and/or reacted 1,5-pentane diisocyanate in an amount of in the range from 3 to 19 wt.%, more preferably in the range from 4 to 15 wt.%, more preferably in the range from 4.5 to 13 wt.%, most preferably in the range from 5 to 10 wt.%, whereby the amount of reacted hexamethylene diisocyanate and/or reacted 1,5-pentane diisocyanate is the amount of hexamethylene diisocyanate and 1,5-pentane diisocyanate used to prepare the polyurethane relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane-vinyl polymer comprises reacted hexamethylene diisocyanate and/or reacted 1,5-pentane diisocyanate in an amount of from 1 to 15 wt.%, preferably from 1 to 12 wt.%, more preferably from 1.5 to 10 wt.%, more preferably from 1.8 to 8 wt.%, most preferably from 2 to 5 wt.%, relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane comprises reacted (I) hexamethylene diisocyanate and/or 1,5-pentane diisocyanate and (II) isophorone diisocyanate and/or dicyclohexylmethane-4,4’-diisocyanate H12MDI in such an amount that the weight ratio of the summed amount of reacted hexamethylene diisocyanate and reacted 1,5-pentane diisocyanate to the summed amount of reacted isophorone diisocyanate and reacted dicyclohexylmethane-4,4’-diisocyanate H12MDI in the polyurethane is in the range from 0.25 to 20, more preferably in the range from 1 to 15, more preferably in the range from 1 to 10, most preferably in the range from 1.2 to 8 or in the range from 1.2 to 5 or in the range from 1.2 to 3 or in the range from 1.2 to 2, whereby the amount of reacted compound x is the amount of compound x used to prepare the polyurethane relative to the total amounts of components used to prepare the polyurethane from which the building blocks from the polyurethane are emanated.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane-vinyl polymer has an acid value of from 0.6 to 20 mg KOH/g, more preferably from 0.6 to 10 mg KOH/g, even more preferably from 0.7 to 7 mg KOH/g, even more preferably from 0.7 to 4 mg KOH/g, most preferably from 0.8 to 3 mg KOH/g, especially preferred in the range from 0.8 to 2.7 mg KOH/g.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane-vinyl polymer has a hydroxy value in the range from 1 to 50 mg KOH/g, more preferably in the range from 1 to 40 mg KOH/g, even more preferably in the range from 1.5 to 35 mg KOH/g, even more preferably in the range from 2 to 30 mg KOH/g, wherein the hydroxy value is determined with the method as described in the description.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the dispersion has a solids content of at least 15 wt.%, more preferably of at least 20 wt.%, more preferably of at least 25 wt.%, more preferably of at least 30 wt.%, more preferably of at least 35 wt.%, more preferably of at least 40 wt.%, most preferably of at least 45 wt.%, and preferably of at most 70 wt.%, more preferably of at most 65 wt.%, even more preferably of at most 60 wt.% or of at most 55 wt.% .

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the dispersed particles have z-average particle size of from 30 to 600 nm, more preferably from 50 to 400 nm, even more preferably from 70 to 350 nm, most preferably from 110 to 275 nm, wherein the z-average particle size is determined with the method according to the description.

Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the dispersed particles have a polydispersity (Mw/Mn) from 9 to 50, preferably from 10 to 40, more preferably from 10 to 35, wherein the polydispersity is determined with the method according to the description. Another aspect of the first embodiment is the composition of any of the aspects of the first embodiment, wherein the polyurethane is obtained by the reaction of at least the following components (A1)-(A3) and optionally (A4):

(A1) At least one polyisocyanate,

(A2) At least one isocyanate-reactive compound that contains at least one salt group which is capable to render the polyurethane dispersible in water and/or at least one functional group that can be converted into a salt group which is capable to render the polyurethane dispersible in water,

(A3) At least one isocyanate-reactive polyol other than (A2), and

(A4) Optionally at least one amino-functional isocyanate reactive compound other than (A2); component A3 comprises at least 50 wt.% of an aliphatic polyester polyol with a hydroxy value of at most 112 mg KOH/g that is preferably obtained from (i) succinic acid, methylsuccinic acid, glutaric acid, adipic acid and/or maleic acid, and (ii) propane-1, 3-diol, butane-1,4-diol, hexane-1,6-diol, epsilon-caprolactone and/or neopentyl glycol; the polyurethane-vinyl polymer comprises from 1 to 15 wt.% of reacted hexamethylene diisocyanate and/or reacted 1,5-pentane diisocyanate, whereby the amount of reacted hexamethylene diisocyanate and/or reacted 1,5-pentane diisocyanate is given relative to the total amount of components used to prepare the polyurethane-vinyl polymer from which the building blocks from the polyurethane-vinyl polymer are emanated; the acid value of the polyurethane-vinyl polymer is in the range from 0.6 to 20 mg KOH/g; and the polyurethane-vinyl polymer particles have a z-average particle size in the range from 30 to 600 nm.

(A1) At least one polyisocyanate,

(A3) At least one isocyanate-reactive polyol other than (A2), and

(A4) Optionally at least one amino-functional isocyanate reactive compound other than (A2); component A3 comprises at least 50 wt.% of an aliphatic polyester polyol with a hydroxy value of at most 112 mg KOH/g that is preferably obtained from (i) succinic acid, methylsuccinic acid, glutaric acid, adipic acid and/or maleic acid, and (ii) propane-1, 3-diol, butane-1,4-diol, hexane-1,6-diol, epsilon-caprolactone and/or neopentyl glycol; the polyurethane-vinyl polymer comprises from 1 to 15 wt.% of reacted hexamethylene diisocyanate and/or reacted 1,5-pentane diisocyanate, whereby the amount of reacted hexamethylene diisocyanate and/or reacted 1,5-pentane diisocyanate is given relative to the total amount of components used to prepare the polyurethane-vinyl polymer from which the building blocks from the polyurethane-vinyl polymer are emanated; the acid value of the polyurethane-vinyl polymer is in the range from 0.6 to 20 mg KOH/g; the hydroxy value of the polyurethane-vinyl polymer is in the range from 0.5 to 20 mg KOH/g;and the polyurethane-vinyl polymer particles have a z-average particle size in the range from 30 to 600 nm.

A first aspect of a second embodiment is a waterborne adhesive composition comprising, consisting essentially of, or consisting of the dispersion according to any one of the aspects of the first embodiment.

Another aspect of the second embodiment is the waterborne adhesive composition of the first aspect of the second embodiment, wherein the adhesive composition comprises, consists essentially of, or consists of the dispersion according to any one of claims 1 to 18 and a crosslinker, preferably one or more polyisocyanates used in an amount of from 0.1 to 20 wt.%, preferably from 0.5 to 10 wt.%, particularly preferably from 1.5 to 6 wt.%, based on the aqueous adhesive composition.

Another aspect of the second embodiment is the waterborne adhesive composition of any of the previous aspects of the second embodiment, wherein the adhesive composition has a solids content of at least 15 wt.%, more preferably of at least 20 wt.%, more preferably of at least 25 wt.%, more preferably of at least 30 wt.%, more preferably of at least 35 wt.%, more preferably of at least 40 wt.%, most preferably of at least 45 wt.% and preferably of at most 70 wt.%, more preferably of at most 65 wt.%, even more preferably of at most 60 wt.% or of at most 55 wt.%.

Another aspect of the second embodiment is the waterborne adhesive composition of any of the previous aspects of the second embodiment, wherein the polyurethane and the vinyl polymer are present in the waterborne adhesive composition in a total amount of at least 65 wt.%, more preferably of at least 70 wt.%, more preferably of at least 75 wt.%, more preferably of at least 80 wt.%, more preferably of at least 85 wt.%, more preferably of at least 90 wt.%, more preferably of at least 95 wt.%, more preferably of at least 99 wt.% or in a total amount of 100 wt.%, relative to the solids content of the waterborne adhesive composition.

A third embodiment is a one-component adhesive composition for the adhesive bonding of one or more substrates, wherein the one-component adhesive composition comprises the waterborne adhesive composition according to any one of the aspects of the second embodiment.

A first aspect of a fourth embodiment is a two-component adhesive composition for the adhesive bonding of one or more substrates, wherein the two-component adhesive composition consists of a first component and a second component, wherein the first component comprises, consists essentially of, or consists of the waterborne adhesive composition according to any one of the aspects of the second embodiment; and the second component comprises a crosslinker.

Another aspect of the fourth embodiment is the two-component adhesive composition of the first aspect of the fourth embodiment, wherein the crosslinker is selected from the group consisting of polyisocyanates, carbodiimides, aziridines, and any combination thereof. Another aspect of the second embodiment is the waterborne adhesive composition of any of the previous aspects of the second embodiment, wherein the adhesive composition Another aspect of the fourth embodiment is the two-component adhesive composition of the first aspect of the fourth embodiment, wherein the crosslinker is one or more polyisocyanates used in an amount of from 0.1 to 20 wt.%, preferably from 0.5 to 10 wt.%, particularly preferably from 1.5 to 6 wt.%, based on the aqueous adhesive composition.

A first aspect of the fifth embodiment is an adhesive film obtained from the adhesive composition of any one of the aspects of the second, third or fourth embodiment.

A second aspect of the fifth embodiment is the adhesive film of the previous aspect of the fifth embodiment, wherein the adhesive film is obtained from the adhesive composition of any one of the aspects of the second, third or fourth embodiment by the heat-activation method.

A sixth embodiment is the use of the adhesive composition of any one of the aspects of the second, third or fourth embodiment in the heat-activation method. A first aspect of a seventh embodiment is a process for adhesively bonding of one or more substrates, wherein the process comprises the following steps:

(1) Applying the adhesive composition of any one of the aspects of the second, third or fourth embodiment on at least a part of at least one of the surfaces of the substrate or of the substrates to be adhesively bonded to obtain a liquid coating (1a),

(3) Activating the liquid coating (1a) (in case step (2) is not applied) or the at least partially dried coating (2a) respectively (in case step (2) is applied) by heating to at least the activation temperature of the liquid coating (1a) or of the at least partially dried liquid coating (2a) respectively to convert the liquid coating (1a) or the at least partially dried coating (2a) into an adhesive state, preferably to a temperature above the melting temperature of the polyurethane-vinyl polymer, and

(4) Joining the one or more substrates.

A second aspect of the seventh embodiment is the process according to the first aspect of the seventh embodiment, wherein the process comprises the following steps:

(4) Joining the one or more substrates.

Another aspect of the seventh embodiment is the process according to any of the aspects of the seventh embodiment, wherein the substrates are composed of wood, metal, plastic, wood composite e.g. MDF boards and panel boards, cork, paper, leather, or textiles; or one of the substrates is composed of wood or fiber molding and the other substrate is a foil, particularly polymer foil, paper optionally coated or impregnated with a polymer, or leather.

Claims

1. A waterborne dispersion for use in an adhesive composition, wherein the dispersion comprises dispersed polymer particles comprising both (i) a polyurethane and (ii) a vinyl polymer, wherein said dispersed particles comprising the polyurethane and the vinyl polymer in a weight ratio of the polyurethane to the vinyl polymer higher than 1 , and the polyurethane-vinyl polymer comprises a crystalline phase having a melting temperature in the range from 30 to 80 °C and an enthalpy of fusion of at least 15 J/g, whereby the melting temperature and the enthalpy of fusion are determined by differential scanning calorimetry according to DIN EN ISO 11357-1 :2017 (2017-02) at a heating rate of 20 K/min.

2. The dispersion according to claim 1 , wherein the polyurethane and the vinyl polymer are present in said dispersed particles in a weight ratio of the polyurethane to the vinyl polymer lower than or equal to 9, preferably in the range of from 1.1 to 8, preferably in the range from 1.2 to 5, more preferably in the range from 1.2 to 4, even more preferably in the range from 1.2 to 3, most preferably in the range from 1.2 to 2.5.

3. The dispersion according to claim 1 or 2, wherein the vinyl polymer has a glass transition temperature T_g and wherein the amount of the vinyl polymer in the polyurethane-vinyl polymer and the glass transition temperature T_g of the vinyl polymer are chosen such that the product obtained by multiplying the T_g (°C ) of the vinyl polymer with the amount (weight fraction) of the vinyl polymer in the polyurethane-vinyl polymer is in the range from -30 to 50, preferably in the range from -15 to 40, more preferably in the range from - 10 to 35, even more preferably in the range from -5 to 30, wherein the glass transition temperature is calculated using the Fox equation.

4. The dispersion according to any one of the preceding claims, wherein said dispersed particles comprising the polyurethane and the vinyl polymer are obtained by free radical polymerization of at least one vinyl monomer in the presence of at least one water- dispersed polyurethane thereby obtaining a hybrid of polyurethane and vinyl polymer (polyurethane-vinyl polymer).

5. The dispersion according to any one of the preceding claims, wherein the polyurethane- vinyl polymer after drying is semicrystalline or crystalline and has a melting temperature in the range from 30 to 80 °C, more preferably in the range from 40 to 70°C, even more preferably in the range from 45 to 55 °C and/or an enthalpy of fusion of at least 15 J/g, preferably of at least 17 J/g, more preferably of at least 18 J/g, more preferably of at least 19 J/g, particularly preferably of at least 20 J/g.

6. The dispersion according to any one of the preceding claims, wherein the polyurethane is obtained by the reaction of at least the following components (A1)-(A3) and optionally (A4):

(A1) At least one polyisocyanate,

(A3) At least one isocyanate-reactive polyol other than (A2), and

7. The dispersion according to claim 6, wherein the polyurethane is the reaction product of: from 5 to 20 wt.%, preferably from 6.5 to 15 wt.%, more preferably from 8 to 13 wt.% of component (A1), from 0.5 to 3.5 wt.%, preferably from 0.6 to 2.5 wt.%, more preferably from 0.7 to 2.0 wt.% of component (A2), from 74.5 to 94.5 wt.%, preferably from 81.5 to 92.8 wt.%, more preferably from 84 to

91.2 wt.% of component (A3), and from 0 to 2 wt.%, preferably from 0.1 to 1 wt.% of component (A4), wherein the amounts of (A1), (A2), (A3) and (A4) add up to 100 wt.%.

8. The dispersion according to any one of the preceding claims, wherein the polyurethane- vinyl polymer has an acid value of from 0.6 to 20 mg KOH/g, more preferably from 0.6 to 10 mg KOH/g, even more preferably from 0.7 to 7 mg KOH/g, even more preferably from 0.7 to 4 mg KOH/g, most preferably from 0.8 to 3 mg KOH/g.

9. The dispersion according to any one of the preceding claims, wherein the polyurethane- vinyl polymer has a hydroxy value in the range from 1 to 50 mg KOH/g, more preferably in the range from 1 to 40 mg KOH/g, even more preferably in the range from 1.5 to 35 mg KOH/g, even more preferably in the range from 2 to 30 mg KOH/g, wherein the hydroxy value is determined with the method as described in the description.

10. The dispersion according to any one of the preceding claims, wherein the dispersion has a solids content of at least 15 wt.%, more preferably of at least 20 wt.%, more preferably of at least 25 wt.%, more preferably of at least 30 wt.%, more preferably of at least 35 wt.%, more preferably of at least 40 wt.%, most preferably of at least 45 wt.% and preferably of at most 70 wt.%, more preferably of at most 65 wt.%, even more preferably of at most 60 wt.% or of at most 55 wt.% .

11. The dispersion according to any one of the preceding claims, wherein the dispersed particles have z-average particle size of from 30 to 600 nm, more preferably from 50 to 400 nm, even more preferably from 70 to 350 nm, most preferably from 110 to 275 nm, wherein the z-average particle size is determined with the method according to the description.

12. A waterborne adhesive composition comprising, consisting essentially of, or consisting of the dispersion according to any one of the preceding claims.

13. The adhesive composition according to claim 12, wherein the adhesive composition comprises, consists essentially of, or consists of the dispersion according to any one of claims 1 to 11 and a crosslinker.

14. A two-component adhesive composition for the adhesive bonding of one or more substrates, wherein the two-component adhesive composition consists of a first component and a second component, wherein the first component comprises, consists essentially of, or consists of the waterborne adhesive composition according to claim 12 or 13; and the second component comprises a crosslinker.

15. Use of the adhesive composition according to any one of claims 12 to 14 for adhesive bonding of one or more substrates by the heat-activation method.

16. A process for adhesively bonding of one or more substrates, wherein the process comprises the following steps:

(1) Applying the adhesive composition of any one of claims 12 to 14 on at least a part of at least one of the surfaces of the substrate or of the substrates to be adhesively bonded to obtain a liquid coating (1a),

(4) Joining the one or more substrates.

17. The process according to claim 16, wherein the process comprises the following steps:

(1) Applying the adhesive composition of any one of claims 12 to 14 on at least a part of at least one of the surfaces of the substrate or of the substrates to be adhesively bonded to obtain a liquid coating (1a), (2) Evaporating of the water present in the liquid coating (1a) to obtain a dry coating (2a), and

(4) Joining the one or more substrates.