CN110835511A

CN110835511A - Adhesive and application thereof

Info

Publication number: CN110835511A
Application number: CN201810932991.5A
Authority: CN
Inventors: 金晨; 朱英丹; 魏松丽; 宋庆林; 张晨曦; 安锦年
Original assignee: Covestro Deutschland AG
Current assignee: Covestro Deutschland AG
Priority date: 2018-08-15
Filing date: 2018-08-15
Publication date: 2020-02-25

Abstract

The invention relates to an adhesive, application thereof and a product bonded by using the adhesive. The adhesive comprises: a. at least one aqueous polyurethane dispersion; b. at least one surface-deactivated polyisocyanate; c. at least one polycarbodiimide having a weight average molecular weight of 500-100000; optionally a carbodiimide having a carbodiimide functionality of 1. The coating formed by the adhesive provided by the invention has good hydrolysis resistance.

Description

Adhesive and application thereof

Technical Field

The invention relates to an adhesive, application thereof and a product bonded by using the adhesive.

Background

The aqueous polyurethane dispersion can be widely applied to the fields of coatings and adhesives. In the field of adhesives, it is common to apply an aqueous polyurethane dispersion to a substrate surface, heat and evaporate the water in the dispersion, subsequently heat-activate (e.g., infrared heating) the dispersion, and finally contact and bond the substrate surface to which the dispersion is applied to other substrate surfaces to obtain a product.

If the hydrolysis resistance of the bonding part of the product is poor, the bonding part of the product is easy to come unstuck when the product is in a high-temperature and high-humidity environment. Therefore, the storage, transportation and use environment of the product can be directly influenced by the hydrolysis resistance.

The industry has improved the hydrolysis resistance of coatings formed by adhesives by increasing their crosslinkability.

US 4870129A discloses an adhesive comprising a crosslinking agent containing isocyanate functional groups and an aqueous polyurethane dispersion containing hydroxyl groups, the crosslinking agent increasing the crosslinkability of the adhesive and improving the resistance to hydrolysis of the coating formed therefrom. The disadvantage is that the adhesive has a short working time, usually only a few hours, which is not suitable for industrial use.

US 6348548 discloses the use of an aqueous dispersion comprising at least one solid surface-deactivated polyisocyanate and at least one isocyanate-reactive polymer for the manufacture of a storage-stable, latent-reactive layer or powder. The disadvantage of this application is that the above-mentioned components require high operating temperatures during the drying and activation of the substrate surface, and are therefore unsuitable for the bonding of substrates which are not resistant to high temperatures.

US2011/0244228 and CN106916273 both disclose an aqueous polyurethane dispersion comprising terminal and pendant carboxyl groups. The aqueous polyurethane dispersion can be crosslinked with carbodiimide, thereby improving the heat resistance of a coating formed from the aqueous polyurethane dispersion.

Therefore, it is desirable to develop an adhesive that forms a coating with good hydrolysis resistance.

Disclosure of Invention

The invention aims to provide an adhesive, application thereof and a product bonded by using the adhesive.

The adhesive according to the present invention comprises:

a. at least one aqueous polyurethane dispersion;

b. at least one surface-deactivated polyisocyanate;

c. at least one polycarbodiimide having a weight average molecular weight of 500-100000; and

d. optionally a carbodiimide having a carbodiimide functionality of 1.

According to one aspect of the invention, there is provided the use of the adhesive provided according to the invention for the preparation of a bonded product.

According to another aspect of the present invention, there is provided a method of manufacturing a bonded product, comprising the steps of:

i. applying an adhesive provided according to the present invention to at least one surface of a substrate;

ii heating and drying the substrate surface to which the adhesive is applied; and

contacting the surface of the substrate treated in step ii with the surface of the substrate itself or of a further substrate to obtain the bonded product.

According to a further aspect of the invention, there is provided a bonded product made according to the method provided by the invention.

The coating formed by the adhesive has good hydrolysis resistance.

Detailed Description

The present invention provides an adhesive comprising: a. at least one aqueous polyurethane dispersion; b. at least one surface-deactivated polyisocyanate; c. at least one polycarbodiimide having a weight average molecular weight of 500-100000; optionally a carbodiimide having a carbodiimide functionality of 1. The invention also provides application of the adhesive and a product bonded by using the adhesive.

Adhesive agent

The term aqueous polyurethane dispersion is also used as a synonym for aqueous polyurethaneurea dispersions and/or aqueous polyurethane polyurea dispersions and/or aqueous polyurea dispersions.

The term sticker refers to a composition capable of bonding an object to itself or to another object, also used as a synonym for adhesive and/or sealant and/or adhesive.

The solids content of the binder is preferably 10% to 90% by weight, based on 100% by weight of the binder.

Aqueous polyurethane dispersions

The aqueous polyurethane dispersion can be added in the form of a dispersion, or can be obtained by adding and mixing the solid polyurethane polymer and water, and most preferably directly adding in the form of a dispersion.

The amount of the solid component of the aqueous polyurethane dispersion is preferably 70 wt% to 99.98 wt%, based on 100 wt% of the solid component of the adhesive.

The acid number of the aqueous polyurethane dispersion is preferably from 0.5mg KOH/g to 10mg KOH/g, most preferably from 0.5mg KOH/g to 5mg KOH/g.

The solid components of the aqueous polyurethane dispersion preferably have a melting enthalpy at 20 to 100 ℃ of more than 3J/g, most preferably 20J/g to 100J/g, obtained by measuring the first temperature rise curve by DSC with a heating rate of 20K/min according to DIN 65467.

The residual content of organic solvent in the aqueous polyurethane dispersion is less than 1.0% by weight, based on 100% by weight of the aqueous polyurethane dispersion.

The solid content of the aqueous polyurethane dispersion is preferably 10% by weight to 70% by weight, more preferably 50% by weight to 65% by weight, and most preferably 50% by weight to 60% by weight, based on 100% by weight of the aqueous polyurethane dispersion.

The aqueous polyurethane dispersion is preferably an anionic and/or nonionic aqueous polyurethane dispersion, most preferably an anionic aqueous polyurethane dispersion.

The anionic aqueous polyurethane dispersion contains a small amount of hydrophilic anionic groups. The amount of hydrophilic anionic groups is preferably from 0.1 meq/100 g solid polyurethane to 15 meq/100 g solid polyurethane, most preferably from 1.6 meq/100 g solid polyurethane to 14 meq/100 g solid polyurethane.

The aqueous polyurethane dispersion is preferably obtained by:

step I) reaction comprising the following components to prepare an isocyanate functional prepolymer:

ia) at least one polyisocyanate,

ib) at least one polymer polyol having a number average molecular weight of preferably from 400g/mol to 8000g/mol, more preferably from 400g/mol to 6000g/mol, most preferably from 600g/mol to 3000g/mol, a hydroxyl functionality of preferably from 1.5 to 6, more preferably from 1.8 to 3, most preferably from 1.9 to 2.1,

ic) optionally a hydroxy-functional compound having a molecular weight of from 32g/mol to 400g/mol, and

id) optionally an isocyanate-reactive anionic hydrophilizing agent or potentially anionic hydrophilizing agent,

step II) reacting all or part of the free isocyanate groups (NCO) of the isocyanate functional prepolymer with:

IIa) at least one amino-functional compound having a molecular weight of from 32g/mol to 400g/mol, and/or

IIb) at least one isocyanate-reactive, preferably amino-functional, anionic hydrophilicizing agent or potentially anionic hydrophilicizing agent;

wherein the resulting isocyanate-functional prepolymer is dispersed in water before, during or after step II), any potential anionic groups present therein being converted into ionic form by partial or complete reaction with a neutralizing agent, preferably after step II).

The solvent still present in the aqueous polyurethane dispersion after dispersion can be removed by distillation. The solvent may also be removed during the dispersion process.

In a preferred embodiment of the preparation of the aqueous polyurethane dispersions, components Ia) to Id) and IIa) to IIb) are used in the following amounts, the individual amounts adding up to 100% by weight:

from 5% to 40% by weight of component Ia),

55% to 90% by weight of Ib),

from 0.5% to 20% by weight of components Ic) and IIa),

0.1 to 25% by weight of components Id) and IIb), wherein 0.1 to 5% by weight of anionic hydrophilicizing agents or potentially anionic hydrophilicizing agents from Id) and/or IIb) are used, based on 100% by weight of components Ia) to Id) and IIa) to IIb).

In another preferred embodiment of the preparation of the aqueous polyurethane dispersions, components Ia) to Id) and IIa) to IIb) are used in the following amounts, where the respective amounts add up to 100% by weight:

from 5% to 35% by weight of component Ia),

60% to 90% by weight of Ib),

from 0.5% to 15% by weight of components Ic) and IIa),

0.1 to 15 wt.% of components Id) and IIb), wherein 0.2 to 4 wt.% of anionic hydrophilicizing agents or potentially anionic hydrophilicizing agents from Id) and/or IIb) are used, based on 100 wt.% of components Ia) to Id) and IIa) to IIb).

In a further preferred embodiment of the preparation of the aqueous polyurethane dispersions, components Ia) to Id) and IIa) to IIb) are used in the following amounts, where the respective amounts add up to 100% by weight:

10% to 30% by weight of component Ia),

65% to 85% by weight of Ib),

from 0.5% to 14% by weight of components Ic) and IIa),

0.1 to 13.5% by weight of components Id) and IIb), wherein 0.5 to 3.0% by weight of anionic hydrophilicizing agents or potentially anionic hydrophilicizing agents from Id) and/or IIb) are used, based on 100% by weight of components Ia) to Id) and IIa) to IIb).

The ratio of isocyanate groups of the polyisocyanates of step I) of component Ia) to isocyanate-reactive groups such as amino, hydroxyl or thiol groups in components Ib) to Id) is from 1.05 to 3.5, preferably from 1.2 to 3.0, most preferably from 1.3 to 2.5.

The polyisocyanates described in step I) component Ia) are preferably one or more of the following: polyisocyanates having an isocyanate functionality of 2 and polyisocyanates containing more than 2 NCO groups per molecule.

The polyisocyanate having an isocyanate functionality of 2 is preferably one or more of the following: 1, 4-butylene diisocyanate, 1, 6-Hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), 2, 4-trimethyl-hexamethylene diisocyanate, 2, 4, 4-trimethyl-hexamethylene diisocyanate, the isomeric bis (4, 4 ' -isocyanatocyclohexyl) methanes, mixtures of isomeric bis (4, 4 ' -isocyanatocyclohexyl) methanes, optionally isomer-containing amounts of 1, 4-cyclohexylene diisocyanate, 1, 4-phenylene diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 1, 5-naphthylene diisocyanate, diphenylmethane-2, 2 ' -diisocyanate, diphenylmethane-2, 4 '-diisocyanate, diphenylmethane-4, 4' -diisocyanate, 1, 3-bis (2-isocyanatoprop-2-yl) -benzene, 1, 4-bis (2-isocyanatoprop-2-yl) -benzene (TMXDI), 1, 3-bis (isocyanatomethyl) benzene (XDI) and alkyl 2, 6-diisocyanato hexanoates containing C1-C8 alkyl groups (lysine diisocyanate), most preferably one or more of the following: 1, 6-Hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), isomeric bis (4, 4 '-isocyanatocyclohexyl) methanes and isomeric bis (4, 4' -isocyanatocyclohexyl) methanes.

The polyisocyanate having an isocyanate functionality of 2 may also be a derivative of the above polyisocyanate having a uretdione, isocyanurate, urethane, allophanate, biuret, imino-oxadiazinedione and/or oxadiazinetrione structure. The derivatives are those having two or more free isocyanate groups.

The polyisocyanate containing more than 2 NCO groups per molecule is preferably one or more of the following: 4-isocyanatomethyloctane 1, 8-diisocyanate (nonane triisocyanate) and triphenylmethane 4, 4', 4 "-triisocyanate.

The polymer polyols described in step I) component Ib) may be those conventionally used in the preparation of aqueous polyurethane dispersions, preferably one or more of the following: polyester polyols, polyacrylate polyols, polyurethane polyols, polycarbonate polyols, polyether polyols, polyester polyacrylate polyols, polyurethane polyester polyols, polyurethane polyether polyols, polyurethane polycarbonate polyols and polyester polycarbonate polyols.

The polyester polyols are preferably polycondensates of dihydric and optionally trihydric and tetrahydric alcohols with dicarboxylic acids and optionally tricarboxylic and tetracarboxylic acids or hydroxycarboxylic acids or lactones. Monocarboxylic acids, preferably benzoic and/or heptanoic acid, can also be used for polycondensation to form polyester polyols when the average functionality of the diols and optionally triols and tetraols is greater than 2.

The diol is preferably one or more of the following: ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycols such as polyethylene glycol, 1, 2-propanediol, 1, 3-butanediol, 1, 4-butanediol, 1, 6-hexanediol and isomers thereof, neopentyl glycol and neopentyl glycol hydroxypivalate, most preferably one or more of the following: 1, 6-hexanediol and its isomers, neopentyl glycol and neopentyl glycol hydroxypivalate.

The trihydric and tetrahydric alcohols are preferably one or more of the following: trimethylolpropane, glycerol, erythritol, pentaerythritol, trimethylolbenzene and trimethylol isocyanurate.

The dicarboxylic acid is preferably one or more of the following: phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, glutaric acid, tetrachlorophthalic acid, maleic acid, fumaric acid, itaconic acid, malonic acid, suberic acid, 2-methylsuccinic acid, 3-diethylglutaric acid and 2, 2-dimethylsuccinic acid. The dicarboxylic acids may also use the corresponding anhydrides as acid sources.

The lactone is preferably one or more of the following: caprolactone, caprolactone homologues, butyrolactone and butyrolactone homologues, caprolactone being most preferred.

The number average molecular weight of the polycarbonate polyols is preferably from 400g/mol to 8000g/mol, most preferably from 600g/mol to 3000 g/mol.

The polycarbonate polyol preferably has a linear structure, most preferably a polycarbonate diol.

The polycarbonate diol preferably comprises 40 wt.% to 100 wt.% hexanediol. The hexanediol is preferably 1, 6-hexanediol and/or hexanediol derivatives. The hexanediol derivatives are preferably based on hexanediol and contain, in addition to terminal hydroxyl groups, ester or ether groups, and can be obtained by reaction of hexanediol with excess caprolactone or by etherification of hexanediol with itself to give dihexylene or trihexylene glycol.

The polyether polyol is preferably one or more of the following: polytetramethylene glycol polyethers and products of the addition of styrene oxide, ethylene oxide, propylene oxide, butylene oxide and/or epichlorohydrin to di-or polyfunctional starter molecules.

The polytetramethylene glycol polyether is preferably obtained from tetrahydrofuran by cationic ring-opening polymerization.

The starter molecule is preferably one or more of the following: water, butyl diglycol, glycerol, diethylene glycol, trimethylolpropane, propylene glycol, sorbitol, ethylenediamine, ethylene glycol, triethanolamine and 1, 4-butanediol.

The Ib) polymer polyol most preferably comprises a polycarbonate polyol and a polytetramethylene glycol polyol. The amount of the polycarbonate polyol and the polytetramethylene glycol polyol is preferably at least 50% by weight, more preferably 60% by weight, and most preferably at least 70% by weight, based on 100% by weight of the polymer polyol.

The amount of the polycarbonate polyol is preferably 20 to 80% by weight, more preferably 25 to 70% by weight, and most preferably 30 to 65% by weight, based on 100% by weight of the sum of the weights of the polycarbonate polyol and the polytetramethylene glycol polyol.

The amount of the polytetramethylene glycol polyol is preferably 20 wt% to 80 wt%, more preferably 30 wt% to 75 wt%, and most preferably 35 wt% to 70 wt%, based on 100 wt% of the sum of the weights of the polycarbonate polyol and the polytetramethylene glycol polyol.

The Ic) hydroxy-functional compound is preferably one or more of the following: polyols having up to 20 carbon atoms, ester diols and monofunctional or isocyanate-reactive hydroxyl-functional compounds.

The polyol having up to 20 carbon atoms is preferably one or more of the following: ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 3-butanediol, cyclohexanediol, 1, 4-cyclohexanedimethanol, 1, 6-hexanediol, neopentyl glycol, hydroquinone dihydroxyethyl ether, bisphenol A (2, 2-bis (4-hydroxyphenyl) propane), hydrogenated bisphenol A (2, 2-bis (4-hydroxycyclohexyl) propane), trimethylolpropane, glycerol and pentaerythritol.

The ester diol is preferably one or more of a-hydroxybutyl-e-hydroxyhexanoate, ω -hydroxyhexyl- γ -hydroxybutyrate, adipic acid- β -hydroxyethyl ester and terephthalic acid- β -hydroxyethyl ester.

The monofunctional or isocyanate-reactive hydroxyl-functional compound is preferably one or more of the following: ethanol, n-butanol, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, 2-ethylhexanol, 1-octanol, 1-dodecanol, 1-hexadecanol, 1, 6-hexanediol, 1, 4-butanediol, neopentyl glycol, and trimethylolpropane, most preferably one or more of the following: 1, 6-hexanediol, 1, 4-butanediol, neopentyl glycol and trimethylolpropane.

Id) the isocyanate-reactive anionic hydrophilizing agent or potentially anionic hydrophilizing agent preferably contains at least one isocyanate-reactive group, such as a hydroxyl group, and at least one functional group, such as-COO^-M⁺、-SO^3-M⁺、-PO(O^-M⁺)₂Wherein M is⁺Preferably one or more of the following: metal cation, H⁺、NH⁴⁺And NHR³⁺R is preferably one or more of the following: c₁-C₁₂Alkyl radical, C₅-C₆Cycloalkyl and C₂-C₄A hydroxyalkyl group. As described aboveThe functional groups enter a pH-dependent dissociation equilibrium upon interaction with the aqueous medium and may thus be negatively or neutrally charged.

Id) the isocyanate reactive anionic hydrophilic agent or potentially anionic hydrophilic agent is further preferably one or more of the following: monohydroxycarboxylic acids, dihydroxycarboxylic acids, monohydroxysulfonic acids, dihydroxysulfonic acids, monohydroxyphosphonic acids, dihydroxyphosphonic acids, and salts thereof, most preferably one or more of the following: those containing carboxylate, carboxylic acid and sulfonate groups.

Said IIa) amino-functional compound is preferably one or more of the following: 1, 2-ethylenediamine, 1, 4-diaminobutane and isophoronediamine.

The IIb) isocyanate-reactive anionic hydrophilising agent or potentially anionic hydrophilising agent preferably contains at least one isocyanate-reactive group, such as a hydroxyl group, and at least one functional group, such as-COO^-M⁺、-SO^3-M⁺、-PO(O^-M⁺)₂Wherein M is⁺Preferably one or more of the following: metal cation, H⁺、NH⁴⁺And NHR³⁺R is preferably one or more of the following: c₁-C₁₂Alkyl radical, C₅-C₆Cycloalkyl and C₂-C₄A hydroxyalkyl group. The functional groups described above enter into a pH-dependent dissociation equilibrium upon interaction with aqueous media and can thus be negatively or neutrally charged.

The aqueous polyurethane dispersion may be prepared by a prepolymer mixing method, an acetone method or a melt dispersion method, and preferably, an acetone method is used.

The acetone process generally begins with the introduction of all or part of Ia) to Id) to prepare an isocyanate-functional prepolymer, and is optionally diluted with a water-miscible, but inert to isocyanate groups, and heated to 50 ℃ to 120 ℃.

The solvent may be a conventional ketone functional aliphatic solvent such as acetone, 2-butanone. The solvent may be added only at the beginning of the preparation, or may be added in part during the preparation as needed.

The solvent may also be one or more of the following: xylene, toluene, cyclohexane, butyl acetate, methoxypropyl acetate, N-methylpyrrolidone, N-ethylpyrrolidone and solvents containing ether or ester units.

Any Ia) to Id) components which were not added at the beginning of the reaction were then metered in.

In the preparation of the isocyanate functional prepolymer from components Ia) to Id), the molar ratio of isocyanate groups to isocyanate reactive groups is from 1.05 to 3.5, preferably from 1.2 to 3.0, most preferably from 1.3 to 2.5.

Components Ia) to Id) are partially or completely converted, preferably completely converted, into an isocyanate-functional prepolymer.

The isocyanate functional prepolymer obtained in step I) may be in a solid state or in a liquid state.

If the isocyanate-functional prepolymer obtained has not yet been dissolved or is only partially dissolved, the prepolymer is further dissolved by means of an aliphatic ketone, such as acetone or 2-butanone.

In step II), NH₂ ^-And/or NH^-The functional component is partially or fully reacted with the residual isocyanate groups of the isocyanate functional prepolymer. Preferably, chain extension or termination is performed prior to dispersion in water.

For chain termination, use is generally made of amino-functional compounds of IIa), preferably one or more of the following: methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, stearylamine, isononyloxypropylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, N-methylaminopropylamine, diethyl (methyl) aminopropylamine, morpholine, piperidine or suitable substituted derivatives thereof, amidoamines made from diprimary amines and monocarboxylic acids, monoketoximes of diprimary amines and primary/tertiary amines.

Component IIa) and component IIb) can optionally be used individually or in admixture in water-diluted or solvent-diluted form, the order of addition being in any order.

Polycarbodiimide

The term carbodiimide functional group corresponds to the structure-N-C-N-.

The polycarbodiimide of the present application may be in the form of a dispersion, a solution, or a solid or a liquid.

The amount of the solid component of the polycarbodiimide is preferably 0.01 wt% to 10 wt%, most preferably 0.1 wt% to 1.5 wt%, based on 100 wt% of the solid component of the binder.

The weight average molecular weight of the polycarbodiimide is preferably 500-100000, more preferably 1000-100000, and most preferably 2000-5000.

The carbodiimide functional group of the polycarbodiimide is preferably from 2 to 50, most preferably from 3 to 6.

The polycarbodiimide preferably comprises the structure of formula I:

wherein n is preferably an integer of 2 or more, more preferably 2 to 50, most preferably 3 to 6; r is preferably one or more of the following: aliphatic organic groups, alicyclic organic groups, and aromatic organic groups containing a C atom and an H atom.

The polycarbodiimide can be synthesized by a generally known method. For example, organic diisocyanates are subjected to decarboxylation condensation in the absence of a solvent or in an inert solvent at a temperature of about 70 ℃ or higher using an organic phosphorus compound or an organic metal compound as a catalyst.

The organic diisocyanate used for preparing the polycarbodiimide is preferably one or more of the following: aromatic diisocyanates, aliphatic diisocyanates and cycloaliphatic diisocyanates, most preferably one or more of the following: 1, 5-naphthalenediisocyanate, 4 '-diphenylmethane diisocyanate, 4' -diphenyldimethylmethane diisocyanate, 1, 3-phenylene diisocyanate, 1, 4-phenylene diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1, 4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4, 4 '-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 3', 5, 5 '-tetraisopropyldiphenyl-4, 4' -diisocyanate and 1, 3, 5-triisopropylbenzene-2, 4-diisocyanate.

The polycarbodiimide is most preferably Desmodur XP 2802.

Carbodiimides having carbodiimide functionality of 1

The term average carbodiimide functional group functionality is the average of the functionalities of one or more polycarbodiimides and optionally one or more carbodiimides having a carbodiimide functional group functionality of 1.

The carbodiimide having a carbodiimide functionality of 1 of the present application may be in the form of a dispersion, solution, solid or liquid.

The adhesive preferably further comprises at least one carbodiimide having a carbodiimide functionality of 1.

The carbodiimide functionality of the carbodiimide having a carbodiimide functionality of 1 preferably has a content of carbodiimide functionality of from 2mmol/g to 10 mmol/g.

The molecular weight of the carbodiimide having a carbodiimide functional group functionality of 1 is preferably 100-450.

The amount of the solid component of the carbodiimide having a carbodiimide functional group functionality of 1 is preferably from 0.1% to 0.5% by weight, based on 100% by weight of the solid component of the adhesive.

The average carbodiimide functionality of the polycarbodiimide and carbodiimide having a carbodiimide functionality of 1 is preferably from 1.1 to 50.

The carbodiimide having a carbodiimide functionality of 1 preferably corresponds to the general formula II:

R-N＝C＝N-R’

II，

wherein R and R' are each independently preferably one or more of the following: aliphatic, alicyclic and aromatic organic radicals containing a C atom and a H atom, most preferably one or more of the following: dicyclohexylcarbodiimide, diisopropylcarbodiimide, diphenylcarbodiimide, bis (methylphenyl) carbodiimide, bis (methoxyphenyl) carbodiimide, bis (nitrophenyl) carbodiimide, bis (dimethylphenyl) carbodiimide, bis (diisopropylphenyl) carbodiimide, bis (di-tert-butylphenyl) carbodiimide, N-ethyl-N' - (3-dimethylaminopropyl) carbodiimide, bis (triphenylsilyl) carbodiimide and cyclic carbodiimide.

Most preferably, the carbodiimide having a carbodiimide functionality of 1 is one or more of: n, N' -diisopropylcarbodiimide and dicyclohexylcarbodiimide.

Surface-deactivated polyisocyanates

The surface-deactivated polyisocyanates herein may be either dispersions or solids.

The amount of the solid component of the surface-deactivated polyisocyanate is preferably 0.01% to 30% by weight, most preferably 0.3% to 30% by weight, based on 100% by weight of the solid component of the adhesive.

The glass transition temperature of the surface-deactivated polyisocyanate is preferably above 30 ℃ and most preferably between 40 ℃ and 100 ℃.

The particle size d50 of the surface-deactivated polyisocyanate is preferably from 500nm to 500. mu.m, more preferably from 1 μm to 500. mu.m, most preferably from 1 μm to 50 μm.

The isocyanate functionality of the surface-deactivated polyisocyanate is preferably 2 to 100, more preferably 3 to 100, most preferably 3 to 6.

The reaction or tackifying temperature of the surface-deactivated polyisocyanate is preferably from 30 ℃ to 180 ℃, most preferably from 40 ℃ to 150 ℃.

The term reaction or adhesion-promoting temperature refers to the temperature at which the isocyanate surface passivation layer dissolves or otherwise breaks down.

The term deactivator is a surface-deactivated polyisocyanate which is capable of reacting with the solid polyisocyanate to achieve stabilization of the solid polyisocyanate.

The passivating agent is preferably one or more of the following: primary aliphatic amines, secondary aliphatic amines, di-or polyamines, hydrazine derivatives, amidines and guanidines, most preferably one or more of the following: ethylenediamine, 1, 3-propylenediamine, diethylenetriamine, triethylenetetramine, 2, 5-dimethylpiperazine, 3 ' -dimethyl-4, 4 ' -diamino-dicyclohexylmethane (-dicyclohexylmethane), methylnonanediamine, isophoronediamine, 4 ' -diaminodicyclohexylmethane, diaminopolypropylene ether, triaminopolypropylene ether, polyamidoamine, monoamine, diamine and polyamine.

The surface-deactivated polyisocyanate is preferably one or more of the following: derivatives of surface-deactivated cycloaliphatic polyisocyanates and surface-deactivated cycloaliphatic polyisocyanates having a uretdione, isocyanurate, carbamate, allophanate, biuret, imino-oxadiazinedione and/or oxadiazinetrione structure, further preferably one or more of the following: surface-deactivated isophorone diisocyanate trimer and surface-deactivated toluene diisocyanate dimer, most preferably surface-deactivated isophorone diisocyanate trimer.

Preparation method of adhesive

The preparation method of the adhesive comprises the following steps: the components of the adhesive provided according to the invention are mixed to obtain the adhesive.

Method for manufacturing bonded product

Preferably, the method further comprises a step iv between steps ii and iii.

The method for manufacturing a bonded product preferably comprises the steps of:

ii heating and drying the substrate surface to which the adhesive is applied;

irradiating the substrate surface treated in step ii with actinic radiation; and

contacting the surface of the substrate treated in step iv with the surface of the substrate itself or of an additional substrate to obtain the bonded product.

The substrate is preferably one or more of the following: wood, plastic, metal, glass, textile, alloy, fabric, artificial leather, paper, cardboard, EVA, rubber, leather, glass fiber, ethylene vinyl acetate copolymer, polyolefin, thermoplastic polyurethane, polyurethane foam, polymer fiber, and graphite fiber, most preferably one or more of the following: EVA, rubber, genuine leather, artificial leather, ethylene vinyl acetate copolymer, polyolefin, thermoplastic polyurethane, and polyurethane foam.

The application may be by applying the adhesive to the entire surface of the substrate or only to one or more portions of the surface of the substrate.

The application may be brushing, dipping, spraying, rolling, knife coating, flow coating, pouring, printing or transferring, preferably brushing, dipping or spraying.

The heating and drying of the surface of the substrate to which the adhesive is applied may mean heating and drying only the surface of the substrate, or heating and drying a part of the substrate including the surface of the substrate to which the adhesive is applied or the entire substrate.

The heating and drying may remove volatile components. The volatile component may be water.

The heating and drying is preferably one or more of: infrared thermal radiation, near infrared thermal radiation, microwaves and the use of convection ovens or spray dryers at elevated temperatures.

The higher the temperature of the heating, the better, but should not be above the temperature limit at which the substrate deforms in an uncontrolled manner or suffers other damage.

The actinic radiation irradiation is preferably carried out at a temperature of the surface of the step ii treated substrate of not less than 35 c, most preferably immediately after the step ii treatment.

The actinic radiation irradiating the substrate surface treated in step ii may refer to irradiating only the substrate surface, or may refer to irradiating a part of the substrate including the substrate surface or the entire substrate.

The actinic radiation crystallizes and cures the adhesive.

The actinic radiation is preferably UV radiation, solar radiation, radiation with inert gases or oxygen-depleted gases excluding oxygen, or radiation with a radiation-transparent medium covering the area to be irradiated, most preferably UV radiation or solar radiation.

The inert gas is preferably nitrogen or carbon dioxide. The radiation-transparent medium is preferably a synthetic film, glass or a liquid such as water.

The UV radiation or solar radiation can be modified with medium-or high-pressure mercury vapor lamps, optionally doped with other elements, such as gallium or iron, or with lasers, pulsed lamps, halogen lamps or excimer radiators.

The actinic radiation is most preferably UV radiation. The UV radiation is most preferably mercury radiation using a fixed installation.

When the substrate has a three-dimensional surface of a complicated shape, it is preferable to perform irradiation using a plurality of irradiation devices, which are arranged appropriately so that the surface receives the irradiation uniformly.

The wavelength of the actinic radiation is preferably from 200nm to 750 nm.

The dose of actinic radiation is preferably not less than 80mJ/cm²Further preferably 80mJ/cm²-5000mJ/cm²More preferably 200mJ/cm²-2000mJ/cm²Most preferably 1250mJ/cm²-1950mJ/cm²。

Within the above range, the higher the dose of actinic radiation, the better, but should not be above the radiation dose limit at which the substrate deforms in an uncontrolled manner or suffers other damage.

The contact is preferably carried out before the temperature of the substrate surface is lowered to a temperature lower than the temperature at which the adhesive can adhere, and more preferably before the temperature of the substrate surface is not lower than 60 ℃.

The surface of the substrate treated in step iv is preferably contacted with the substrate itself or an additional substrate within one hour, more preferably within 30 minutes, still more preferably within 10 minutes, and most preferably within 5 minutes to obtain the bonded product.

The additional substrate may be any substrate that requires adhesion.

The additional substrate and the base material may be the same or different.

The additional substrate is preferably coated, heated and treated with actinic radiation as the substrate.

The additional substrate is preferably not treated with a primer, high energy radiation or ozone prior to contacting the substrate surface.

The high-energy radiation may be ionizing radiation, in particular plasma.

After contacting the substrate surface treated in step ii or step iv with the substrate itself or the additional substrate, a further heat treatment may be carried out.

After contacting the surface of the substrate treated in step ii or iv with the substrate itself or the additional substrate, a further cooling treatment may be performed to reduce the temperature of the bonded product to room temperature.

The method of introducing heat is preferably one or more of the following: convection ovens or spray dryers, infrared thermal radiation, near infrared thermal radiation, microwaves and objects in contact with substrates coated with the adhesives of the invention are used to transfer heat at elevated temperatures.

Preferably, no heat is introduced to the substrate surface after said step ii treatment or after said step iv treatment before said substrate surface is contacted with said substrate itself or another substrate.

Adhesive product

The adhesive product is preferably a shoe.

Drawings

The invention will be described and explained in more detail below with reference to the drawings, in which:

FIG. 1 is a schematic illustration of the adhesion of a black rubber sample.

FIG. 2 is a schematic diagram of hydrolysis resistance test.

Examples

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the event that a definition of a term in this specification conflicts with a meaning commonly understood by those skilled in the art to which the invention pertains, the definition set forth herein shall govern.

Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth herein are approximations that can vary depending upon the desired properties to be obtained.

As used in this specification, the terms "a", "an" and "the" are intended to include "at least one" or "one or more" unless otherwise indicated. For example, "a component" refers to one or more components, and thus more than one component may be considered and may be employed or used in the practice of the described embodiments.

As used herein, "and/or" means one or all of the referenced elements.

As used herein, "comprising" and "comprises" encompass the presence of only the recited elements as well as the presence of other, non-recited elements in addition to the recited elements.

All percentages in the present invention are by weight unless otherwise indicated.

The analytical measurements according to the invention were carried out at 23. + -. 2 ℃ and 50. + -. 5% humidity, unless otherwise stated.

The solids content of the dispersions was determined using a HS153 moisture meter from Mettler Toledo according to DIN-EN ISO 3251.

The isocyanate group (NCO) content is determined volumetrically according to DIN-EN ISO 11909 and the data determined include the free and potentially free NCO content.

The carbodiimide functionality of a carbodiimide is the number of carbodiimide functional groups contained in a single carbodiimide molecule.

The carbodiimide functional group of the polycarbodiimide is the average number of carbodiimide functional groups contained in a single polycarbodiimide molecule.

The average carbodiimide functional group can be calculated. For example: when the adhesive contained 0.13g N, N' -diisopropylcarbodiimide (DIC, molecular weight 126, functionality 1) and 1g Desmodur XP2802 (40% by weight solids, number average molecular weight 1779, average functionality 4.5), the average carbodiimide functionality was calculated as follows:

(0.13/126*1+1*0.4/1779*4.5)/(0.13/126+1*0.4/1779)＝1.63

the acid number is measured in accordance with DIN EN ISO 211.

The viscosity was measured at 23 ℃ according to DIN 53019 using a Brookfield DV-II + Pro. rotational viscometer.

Glass transition temperature (Tg) was measured by differential scanning calorimetry using a TA Auto Q20 DSC at a ramp rate of 10 deg.C/min.

Melting point temperature (T)_m) Measured by DSC with a heating rate of 20K/min according to DIN 65467.

The particle size d50 was determined using laser spectroscopy (as measured by a ZatasizerNano ZS 3600 laser particle sizer from Malvern instruments) after dilution with deionized water.

Hydroxyl number was determined according to ASTM D4274.

The number average molecular weight and weight average molecular weight were determined by gel permeation chromatography using tetrahydrofuran as the mobile phase, against polystyrene standards at 23 ℃.

Raw materials and reagents

DCC: dicyclohexylcarbodiimide having a melting point of 37.42 ℃, a carbodiimide functionality of 4.9mmol/g, a molecular weight of 206 and a carbodiimide functionality of 1.

DIC: n, N' -diisopropylcarbodiimide, carbodiimide functionality of 7.9mmol/g, molecular weight 126, carbodiimide functionality of 1.

Desmodur XP 2802: 40% by weight solids, hydrophilically modified polycarbodiimide, the solid component having a melting point temperature of 23.16 ℃, a carbodiimide functionality of 1mmol/g, a number average molecular weight of 1779, a weight average molecular weight of 3258 and a carbodiimide functionality of 4.5, available from Corsai Kogyo Co.

2589: 100% by weight solids, a glass transition temperature of 67.75 ℃, a melting point of the solid component of more than 200 ℃, an isocyanate functionality of not less than 3, a particle size d50 of about 1.5 μm, a reaction or tackifying temperature of 70 ℃ to 120 ℃ of isophorone diisocyanate (IPDI) trimer, commercially available from CorsgingIn GmbH.

Dispercoll BL XP 2514: 40% solids by weight, melting point of the solid component greater than 155 ℃, isocyanate functionality of 2, particle size d50 of about 10 μm, Toluene Diisocyanate (TDI) dimer, reaction or tackifying temperature of 60 ℃ to 90 ℃, commercially available from Corss Corp.

Polyester I: 1, 4-butanediol polyadipate diol having a hydroxyl number of 50 was purchased from Corss Corp.

Polyester II: polyester diol consisting of 1, 6-hexanediol, neopentyl glycol and adipic acid, having a hydroxyl number of 66, was purchased from Cornstitus, Inc.

LB 25: monofunctional polyether polyols based on ethylene oxide/propylene oxide having a number average molecular weight of 2250g/mol and a hydroxyl number of 25 were obtained from Corss Corning Ltd.

1, 6-hexamethylene diisocyanate, available from Corsin GmbH.

Isophorone diisocyanate, available from Corss Chungsu Co.

DMPA: 2, 2-dimethylolpropionic acid, available from Aldrich chemical company.

AAS: diamino sulfonic acid sodium NH₂-CH₂CH₂-NH-CH₂CH₂-SO₃Na, 45% concentration in water, was purchased from Colesi Indo Co.

L-lysine: 50% L-lysine in water, purchased from Xiamen Crane chemical.

Polyetheramines, available from hensman.

Tamol NN 4501: dispersant, available from BASF.

Emulvin WA: emulsifier, 15% by weight concentration, available from Langshen.

Borchigel ALA: thickener, 50% by weight concentration in deionized water, available from OMG.

Rubber treating agent: powder B (trichloroisocyanuric acid) was dissolved in ethyl acetate at a concentration of 2% by weight.

BorchigelL 75N: thickener, available from OMG.

Preparation of aqueous polyurethane dispersions 1 to 3

Aqueous polyurethane Dispersion 1(PUD1)

607.5g of polyester I and 57.4g of polyester II were dewatered at 110 ℃ for 1 hour at 15mbar, 3.0g of 1, 4-butanediol were added and the mixture was cooled while stirring. 51.1g were added at 60 ℃

Then 33.8g of

The mixture was stirred at 80 ℃ to 90 ℃ until an isocyanate content of 1.3% was reached. The reaction mixture was dissolved in 1050g of acetone and cooled to 50 ℃. After a solution of 7.0g of AAS, 0.9g of dihydroxyethylamine and 2.7g of L-lysine in 80g of water was added to the reaction mixture solution and vigorously stirred for 30 minutes, 675g of water was added to disperse the mixture, followed by distillation to separate out the acetone, to give an aqueous polyurethane dispersion 1 having an acid value of 0.93mgKOH/g, a melting point temperature of the solid component of the dispersion of 42.90 ℃, a melting enthalpy of 38.52J/g, a solid content of 50.6% by weight and an amount of hydrophilic anionic groups of 4.8 meq/100 g of solid polyurethane.

Aqueous polyurethane Dispersion 2(PUD2)

607.5g of polyester I and 57.4g of polyester II were dewatered 1 at 110 ℃ and 15mbarAfter a further hour, 3.0g of 1, 4-butanediol are added and the mixture is cooled while stirring. 51.1g were added at 60 ℃Then 33.8g ofThe mixture was stirred at 80 ℃ to 90 ℃ until an isocyanate content of 1.3% was reached. The reaction mixture was dissolved in 1050g of acetone and cooled to 50 ℃. After a solution of 7.0g of AAS, 0.9g of dihydroxyethylamine and 1.1g of diethanolamine in 80g of water was added to the reaction mixture solution and vigorously stirred for 30 minutes, 700g of water was added to disperse the mixture, followed by distillation to separate out the acetone, to give an aqueous polyurethane dispersion 2 having an acid value of 0.39, a melting point temperature of the solid component of the dispersion of 47.19 ℃, a melting enthalpy of 41.94J/g, a solid content of 51.9% by weight and an amount of hydrophilic anionic groups of 4.8 meq/100 g of solid polyurethane.

Aqueous polyurethane Dispersion 3(PUD3)

607.5g of polyester I, 57.4g of polyester II and 7.6g of LB25 were dewatered at 110 ℃ for 1 hour at 15mbar, 1.4g of 1, 4-butanediol and 2.5g of DMPA were added and the mixture was cooled while stirring. 51.1g were added at 60 ℃

Then 33.8g of

The mixture was stirred at 80 ℃ to 90 ℃ until an isocyanate content of 1.3% was reached. The reaction mixture was dissolved in 1050g of acetone and cooled to 50 ℃. After a solution of 7.0g of AAS, 1.2g of dihydroxyethylamine and 1.9g of 2- (2-aminoethylamino) ethanol in 85g of water was added to the reaction mixture solution and stirred vigorously for 30 minutes, 685g of water was added to disperse the mixture, followed by distillation to separate out acetone, aqueous polyurethane dispersion 3 was obtained which had an acid value of 1.05mg KOH/g, a melting point temperature of the solid component of the dispersion of 47.99 ℃, a melting enthalpy of 43.8J/g, and a solids content of 50.5% by weightAmount%, the amount of hydrophilic anionic groups was 4.8 meq/100 g solid polyurethane.

Preparation of Adhesives

110.19g of deionized water and 2.58g of deionized water were mixed

Mixing and stirring at 600rpm per minute for 3 minutes, adding 0.82g of Tamol NN 4501 and stirring for 3 minutes, adding 0.59g of Emulvin WA and stirring for 3 minutes to obtain a mixture. Will be in accordance with the amounts shown in Table 1

2589 were divided into 7 portions and stirred at 1000rpm per minute

2589 to the mixture, the stirring is continued for 20 minutes, and finally 14.07g of Borchigel ALA are added and the stirring is continued for 30 minutes to give a mixture comprising the surface-deactivated polyisocyanate;

the components shown in Table 1, a preformed polyisocyanate mixture containing surface passivation and 0.5g of Borchigel L75N were mixed and stirred at 600rpm per minute for 25 minutes to give a sticker.

Hydrolysis resistance test

Mechanically polishing black rubber (8cm by 2.54cm), adding a rubber treatment agent, baking in an oven at 50 ℃ for 3 minutes, taking out, and standing at normal temperature for 2 hours. The adhesive was applied to the pretreated black rubber using a brush, dried in an oven at 60 ℃ and activated for 3 minutes. The two pieces of black rubber were immediately attached under 4bar pressure for 10 seconds as shown in FIG. 1, and then stored at room temperature (23. + -. 2 ℃ C., 50. + -. 5% RH) for 2 days to obtain a sample for testing.

A 1kg weight was loaded on the sample, and the sample was placed in a Hitachi box at a temperature of 70 ℃ and a relative humidity of 95%, as shown in fig. 2. The time to full open for degumming of the two pieces of black rubber of the sample was recorded, the shorter the time to full open for degumming, the worse the hydrolysis resistance of the coating formed by the adhesive.

Table 1 lists the compositions of the adhesives of the examples and comparative examples of the invention and the sample open time for degumming.

TABLE 1 composition of adhesives and sample degumming full open time for examples and comparative examples

Remarking: the amounts of each aqueous dispersion in the table refer to the weight of water.

Comparing comparative examples 1 to 8 and examples 1 to 10, it is shown that the samples bonded with the adhesive of the present invention each had a full open time for degumming of not less than 1.3 hours, which is longer than that of the samples bonded with the adhesive of the comparative examples, and that the coating formed with the adhesive of the present invention has a better hydrolysis resistance than that of the comparative examples.

Comparing comparative example 5 with examples 1-2, the average carbodiimide functionality of the polycarbodiimide and carbodiimide having a carbodiimide functionality of 1 of examples 1-2 and of example 1-2 is not less than 1.1, and the average carbodiimide functionality of the polycarbodiimide and carbodiimide having a carbodiimide functionality of 1 of comparative example 5 is less than 1.1, the open time to failure of the samples bonded with the adhesive of comparative example 5 is significantly shorter than the open time to failure of the samples bonded with the adhesives of examples 1-2, indicating that the coatings formed with the adhesives of the invention have much better resistance to hydrolysis than the comparative examples.

Comparing examples 1-2, 8-10 and 3-7, the acid value of the aqueous polyurethane dispersion contained in the adhesive of examples 1-2, 8-10 was 0.5mg KOH/g or more, the acid value of the aqueous polyurethane dispersion contained in the adhesive of examples 3-7 was less than 0.5mg KOH/g, and the degumming full open time of the samples bonded with the adhesives of examples 1-2, 8-10 was significantly longer than that of the samples bonded with the adhesives of examples 3-7, which shows that the acid value of the aqueous polyurethane dispersion has a significant effect on the hydrolysis resistance of the coating formed with the adhesive.

Comparing examples 9 and 10, the adhesive of example 10 comprised a surface-deactivated polyisocyanate having an NCO functionality of 2, the adhesive of example 9 comprised a surface-deactivated polyisocyanate having an NCO functionality of 3, and the adhesive of example 10 bonded samples having significantly shorter open time to debond than that of example 9, indicating that the NCO functionality of the surface-deactivated polyisocyanate has a significant effect on the hydrolysis resistance of the coating formed by the adhesive.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing description, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description; and therefore any changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. An adhesive, comprising:

a. at least one aqueous polyurethane dispersion;

b. at least one surface-deactivated polyisocyanate;

d. optionally a carbodiimide having a carbodiimide functionality of 1.

2. The adhesive of claim 1, wherein the amount of the solid component of the aqueous polyurethane dispersion is 70 wt% to 99.98 wt%, based on 100 wt% of the solid component of the adhesive.

3. Adhesive according to claim 1, wherein the aqueous polyurethane dispersion has an acid number of from 0.5mg KOH/g to 10mg KOH/g, preferably from 0.5mg KOH/g to 5mg KOH/g.

4. The adhesive according to claim 1, wherein the solid components of the aqueous polyurethane dispersion have a melting enthalpy of more than 3J/g at 20 to 100 ℃ as determined by DSC with a heating rate of 20K/min according to DIN65467 by measuring the first temperature rise curve.

5. The adhesive of claim 1, wherein the solid component of the polycarbodiimide is present in an amount of 0.01 wt% to 10 wt% based on 100 wt% of the solid component of the adhesive.

6. The adhesive of claim 1, wherein the polycarbodiimide has a weight average molecular weight of 1000-100000.

7. An adhesive according to claim 1, wherein the polycarbodiimide has a carbodiimide functionality of from 2 to 50, preferably from 3 to 6.

8. The adhesive of claim 1 wherein the polycarbodiimide and carbodiimide having a carbodiimide functional functionality of 1 has an average carbodiimide functional functionality of from 1.1 to 50.

9. Adhesive according to claim 1, characterized in that the amount of the solid component of the surface-deactivated polyisocyanate is 0.01% to 30% by weight, preferably 0.3% to 30% by weight, based on 100% by weight of the solid component of the adhesive.

10. Adhesive according to claim 1, wherein the surface-deactivated polyisocyanate has a glass transition temperature of more than 30 ℃, preferably from 40 ℃ to 100 ℃.

11. Adhesive according to claim 1, wherein the surface-deactivated polyisocyanate has a particle size d50 of 500nm to 500 μm, preferably 1 μm to 500 μm.

12. Adhesive according to claim 1, wherein the surface-deactivated polyisocyanate has an isocyanate functionality of 2 to 100, preferably 3 to 100.

13. The adhesive of claim 1, wherein the surface-deactivated polyisocyanate is one or more of: surface-deactivated cycloaliphatic polyisocyanates and surface-deactivated derivatives of cycloaliphatic polyisocyanates having uretdione, isocyanurate, carbamate, allophanate, biuret, imino-oxadiazinedione and/or oxadiazinetrione structures, preferably one or more of the following: surface-deactivated isophorone diisocyanate trimer and surface-deactivated toluene diisocyanate dimer, most preferably surface-deactivated isophorone diisocyanate trimer.

14. Use of the adhesive according to any one of claims 1 to 13 for the preparation of an adhesive product.

15. A method of making a bonded product comprising the steps of:

i. applying the adhesive according to any one of claims 1-13 to at least one surface of a substrate;

heating and drying the substrate surface to which the adhesive is applied; and

16. The method of claim 15, further comprising a step iv between step ii and step iii of irradiating the surface of the substrate treated in step ii with actinic radiation.

17. The method of claim 15, wherein the substrate is one or more of: wood, plastic, metal, glass, textile, alloy, fabric, artificial leather, paper, cardboard, EVA, rubber, leather, glass fiber, ethylene vinyl acetate copolymer, polyolefin, thermoplastic polyurethane, polyurethane foam, polymer fiber, and graphite fiber.

18. A bonded product made according to the method of any one of claims 15-17.

19. A bonded product according to claim 18 wherein the bonded product is a shoe.