CN113583620B - UV curing adhesive with excellent adhesive force and preparation method thereof - Google Patents

Abstract

The invention discloses a UV curing adhesive with excellent adhesive force and a preparation method thereof, wherein the UV curing adhesive comprises (A) a resin prepolymer, (B) a monomer compound, (C) a photoinitiator, (D) tackifying resin and other auxiliaries; wherein the molecular chain end of the resin prepolymer has at least 2 functional groups curable by UV free radical light; the monomer compound is a diluted monomer compound and has single or multiple free radical photo-curing functional groups; the tackifying resin is obtained by solution free radical polymerization and functional group modification, and contains a photocuring functional group. The UV curing adhesive provided by the invention ensures that the surface of a cured product is dry and comfortable, has excellent oxidation and polymerization resistance, has excellent adhesion to various metals, plastics and other substrates, and especially has excellent adhesion and cracking resistance under severe conditions such as low temperature, high humidity and the like.

Description

UV curing adhesive with excellent adhesive force and preparation method thereof

Technical Field

The invention belongs to the field of photocuring materials, and particularly relates to a UV curing adhesive with excellent adhesive force and a preparation method thereof.

Background

In the electronic and electrical industry, adhesives are generally required to be used for shaping, positioning, bonding and the like of electronic components, and the types of commonly used adhesives include bi-component acrylic structural adhesives, anaerobic adhesives, epoxy adhesives, polyurethane adhesives, organic silicon adhesives, UV-cured acrylic adhesives and the like. The bi-component acrylic structural adhesive is generally high in bonding strength, but poor in toughness, easy to fluctuate in mixing amount and the like; the anaerobic adhesive has the problem that the exposed position of air is not cured; the epoxy adhesive has high hardness, large internal stress, insufficient high and low temperature impact resistance toughness and the like after being cured; the polyurethane adhesive generally has active isocyanate functional groups, is easy to cause allergy and has a general curing speed; free D3-D10 dimethyl siloxane micromolecule siloxane ring bodies inevitably exist in the organic silicon adhesive, and the organic silicon adhesive is not suitable for some precise electronic components. The UV curing acrylic adhesive is more and more favored in the electronic and electric appliance industry due to the advantages of high curing efficiency, no VOC (volatile organic compounds) emission and the like.

The UV-curable acrylic adhesive generally comprises an acrylic resin prepolymer (such as polyurethane acrylic resin, epoxy acrylic resin or polyester acrylic resin), a diluent monomer, an initiator and other auxiliaries. In a general UV curing acrylic adhesive, an initiator free radical reacts with oxygen to generate a peroxide free radical, and the peroxide free radical is not enough to initiate the reaction of a prepolymer and a diluent monomer, so that an oxygen inhibition phenomenon of surface stickiness occurs.

In the use process of actual transportation or production of some electronic devices, the temperature rises during operation and returns to the room temperature after the operation is stopped, and the electronic devices can also be used in a high-humidity environment, so that a fixing piece with excellent high and low temperature resistance and high temperature and high humidity resistance is needed, and a large number of fastening screws used in the filter industry belong to the working condition.

The traditional UV curing acrylic adhesive has the technical problems of low adhesive force and colloid cracking easily under high-low temperature circulation and high-temperature, high-humidity and aging conditions even if flexible polyurethane acrylic resin is used.

Therefore, the UV-cured acrylic adhesive which has excellent oxygen resistance and polymerization inhibition capacity, and has excellent adhesive force and toughness under the conditions of high-low temperature circulation, high temperature, high humidity and aging is developed, and the UV-cured acrylic adhesive has very important market value.

Disclosure of Invention

In order to solve the technical problems, the invention provides the UV curing adhesive with excellent adhesive force and the preparation method thereof, which can be used for bonding and positioning in the electronic and electric appliance industry, have high reliability of curing efficiency and low or no VOC emission, and particularly have excellent oxygen inhibition and polymerization inhibition capacity, adhesive force and toughness when being applied to high and low temperature circulation and high temperature, high humidity and aging conditions.

In the present invention, a UV curing adhesive with excellent adhesion, which solves the above technical problems, includes: (a) a resin prepolymer having at least 2 UV free-radically curable functional groups at the molecular chain ends, (B) a monomer compound having a single or multiple free-radically photocurable functional groups, (C) a photoinitiator, (D) a tackifying resin, optionally (E) other auxiliaries;

the resin prepolymer (a) is used in an amount of 0 to 90wt.%, preferably 5 to 80 wt.%, preferably 8 to 70wt.%, preferably 9 to 60 wt.%, preferably 10 to 50wt.%, preferably 15 to 40 wt.%, preferably 18 to 35 wt.%, preferably 20 to 30wt.%, for example 21 wt.%, 22 wt.%, 23 wt.%, 24 wt.%, 25 wt.%, 26 wt.%, 27 wt.%, 28 wt.%, 29 wt.%, based on the total mass of (a), (B), (C), and (D); the monomer compound (B) is used in an amount of 0 to 70wt.%, preferably 5 to 60 wt.%, preferably 20 to 50wt.%, preferably 25 to 45 wt.%, preferably 30 to 40 wt.%, for example 31 wt.%, 32 wt.%, 33 wt.%, 34 wt.%, 35 wt.%, 36 wt.%, 37 wt.%, 38 wt.%, 39 wt.%; the amount of the initiator (C) is 0.1 to 10wt.%, preferably 0.2 to 9 wt.%, preferably 0.5 to 8wt.%, preferably 0.8 to 7 wt.%, preferably 0.9 to 6 wt.%, preferably 1 to 5wt.%, preferably 2 to 4 wt.%, preferably 2.5 to 3.5 wt.%; the amount of said tackifying resin (D) is from 5 to 50wt.%, preferably from 6 to 45 wt.%, preferably from 7 to 40 wt.%, preferably from 8 to 35 wt.%, preferably from 10 to 30wt.%, preferably from 15 to 25 wt.%, for example 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.%, 20 wt.%, 21 wt.%, 22 wt.%, 23 wt.%, 24 wt.%; the other auxiliaries (E) are used in amounts of from 0 to 10 parts by weight, for example from 1 to 9 parts by weight, from 2 to 8 parts by weight, from 3 to 7 parts by weight, from 4 to 7 parts by weight, from 5 to 6 parts by weight, based on 100 parts by weight of the combination of (A), (B), (C) and (D), and the amounts of each of (A) and (B) cannot be 0% by weight at the same time.

In general, the sum of the amounts of component (A) and component (B) is from 40 to 90% by weight, preferably from 45 to 89% by weight, preferably from 50 to 88% by weight, preferably from 55 to 87% by weight, preferably from 60 to 86% by weight, preferably from 63 to 86% by weight, preferably from 65 to 86% by weight, preferably from 68 to 86% by weight, preferably from 70 to 85% by weight, preferably from 72 to 84% by weight, preferably from 73 to 83% by weight, preferably from 74 to 82% by weight, preferably from 75 to 81% by weight, for example from 76% by weight, 77% by weight, 78% by weight, 79% by weight or 80% by weight, based on the total mass of (A), (B), (C) and (D).

The tackifying resin (D) is obtained by scheme 1 below:

step (1): polymerizing a carboxyl group-containing radical polymerizable monomer (I) with a radical comonomer (II) free of free carboxyl groups and hydroxyl groups in a solvent under the action of a radical initiator, controlling the molecular weight of the product using a chain transfer agent, and obtaining a radical copolymer P1;

step (2): reacting the radical polymer P1 in the step (1) with an epoxy group-containing unsaturated compound having radical polymerizability, preferably under the action of a catalyst, and evaporating the solvent to obtain a tackifying resin (D); wherein, carboxyl on the lateral group of the P1 molecular chain is converted into a functional group with photocuring free radical polymerization property. The tackifying resin (D) obtained in scheme 1 has a number average molecular weight in the range of 1000 to 20000, preferably 2000 to 18000, more preferably 3000 to 17000, more preferably 4000 to 16000, more preferably 5000 to 15000, 6000 to 14000, 7000 to 13000, 8000 to 12000 or 9000 to 11000, for example 10000.

Or by scheme 2 below:

step (1'): polymerizing a hydroxyl-containing radical polymerizable monomer (III) and a radical comonomer (II) free of free carboxyl and hydroxyl groups in a solvent under the action of a radical initiator, controlling the molecular weight of the product by using a chain transfer agent, and obtaining a product obtained from a radical polymer M1;

step (2'): the free-radical polymer M1 obtained in step (1') is reacted with a compound having a free-radically polymerizable isocyanate functional group, preferably in the presence of a catalyst, and the solvent is distilled off to obtain a tackifier resin (D). Wherein, hydroxyl on the molecular chain side group of M1 is converted into a functional group with photocuring free radical polymerization property. The number average molecular weight of the tackifying resin (D) obtained in embodiment 2 is in the range of 1000 to 20000, preferably 2000 to 18000, more preferably 3000 to 17000, more preferably 4000 to 16000, more preferably 5000 to 15000, 6000 to 14000, 7000 to 13000, 8000 to 12000 or 9000 to 11000, for example 10000.

Further, the carboxyl group-containing radical polymerizable monomer (I) in the step (1) is one or more selected from C3-C15 unsaturated carboxylic acids (preferably C3-C10 unsaturated carboxylic acids, more preferably C3-C6 unsaturated carboxylic acids such as unsaturated carboxylic acids like acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, preferably acrylic acid or methacrylic acid), the ratio of the carboxyl group-containing radical polymerizable monomer (I) to the total amount of the reactive monomers is 3 to 50wt%, preferably 4 to 40wt%, preferably 5 to 30wt%, preferably 8 to 25wt%, preferably 10 to 20wt%, preferably 12 to 18wt%, for example 15 to 16wt%, and the amount of the radical comonomer (II) not containing a free carboxyl group and a hydroxyl group to the total amount of the reactive monomers is 50 to 97wt%, preferably 70 to 95wt%, preferably 75 to 92wt%, preferably 80 to 90wt%, preferably 82 to 88wt%, preferably 84 to 85wt%.

The unsaturated compound containing epoxy groups with radical polymerization in the scheme 1 is one or more of glycidyl (meth) acrylate, 3,4-epoxycyclohexyl methacrylate and 4-vinylbenzyl glycidyl ether, and the ratio of the molar amount of epoxy functional groups to the molar amount of carboxyl groups in the step (1) in the step (2) is from 0.05 to 0.99.

A catalyst for promoting the reaction of the carboxyl group with the epoxy functional group may be used in the step (2), and is preferably a quaternary ammonium salt catalyst such as one or more of benzyltriethylammonium chloride, trioctylmethylammonium chloride, tetramethylammonium bromide, tetrapropylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, triethylbenzylammonium bromide, triethylhexylammonium bromide, triethyloctylammonium bromide, and more preferably tetrabutylammonium bromide.

Further, in scheme 2, in step (1'), the hydroxyl group-containing radically polymerizable monomer (III) is one or more selected from the group consisting of a (meth) acrylate having a hydroxyl group, a (meth) acrylate having a phenolic hydroxyl group, hydroxystyrene, and the like, such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and p-hydroxystyrene; the proportion of the hydroxyl group-containing polymerizable radical monomer (III) to the total amount of the reactive monomers in scheme 2 (comprising the sum of both the hydroxyl group-containing polymerizable radical monomer (III) and the comonomer (II)) is from 3 to 50% by weight, preferably from 5 to 30% by weight, preferably from 8 to 25% by weight, preferably from 10 to 20% by weight, preferably from 12 to 18% by weight, for example from 15 to 16% by weight; the amount of comonomer (II) used is in the range from 50 to 97% by weight, preferably from 70 to 95% by weight, preferably from 75 to 92% by weight, preferably from 80 to 90% by weight, preferably from 82 to 88% by weight, preferably from 84 to 85% by weight.

Further, in the embodiment 2, the isocyanate functional group-containing compound having radical polymerization property is one or more selected from 2-acryloxyethyl isocyanate (AOI), 2-methacryloxyethyl isocyanate (MOI), and 2- [2- (methacryloyloxy) ethoxy ] ethyl isocyanate (MOI-EG); step (2 ') satisfies that the ratio of the molar amount of isocyanate groups to the molar amount of hydroxyl groups in step (1') is from 0.05 to 0.99, preferably from 0.1 to 0.9.

The catalyst for promoting the reaction of hydroxyl and isocyanic acid radical in the step (2') is organic bismuth or organic tin catalyst such as stannous octoate, dioctyl tin oxide, dioctyl tin dilaurate, dibutyltin dilaurate, bismuth naphthenate and the like, preferably dibutyltin dilaurate.

Preferably, the comonomer (II) used in the above-mentioned schemes 1 and 2 is one or more selected from the group consisting of (meth) acrylic acid alkyl esters, cycloalkyl (meth) acrylates, aryl (meth) acrylates, aralkyl (meth) acrylates, vinyl aromatics, conjugated dienes, etc., such as one or more selected from the group consisting of (meth) propionic acid methyl esters, dicyclopentadiene acrylates, phenyl methacrylates, benzyl methacrylates, styrene, 1,3-butadiene. More preferably, in schemes 1 and 2, the comonomer (II) is a copolymer comprising at least one alkyl (meth) acrylate such as butyl methacrylate (28-35 wt%, preferably 30-34wt%, e.g. 31wt%,32wt% or 33wt% of the total amount of reactive monomers), at least one cycloalkyl (meth) acrylate such as dicyclopentadiene acrylate (6-15 wt%, preferably 8-12wt%, e.g. 9wt%, 10wt% or 11wt% of the total amount of reactive monomers), at least one aryl (meth) acrylate such as benzyl methacrylate (30-40 wt%, preferably 33-37wt%, e.g. 34wt%,35wt% or 36wt% of the total amount of reactive monomers).

Preferably, the solvent in the schemes 1 and 2 is one or more of a C1-C8 organic alcohol (preferably a C2-C6 organic alcohol, such as ethanol, propanol, etc.), a C2-C14 glycol ether (preferably a C4-C10 glycol ether, such as ethylene glycol alkyl ether acetate, diethylene glycol monoalkyl ether, diethylene glycol dialkyl ether, dipropylene glycol dialkyl ether, propylene glycol monoalkyl ether, propylene glycol alkyl ether acetate), a C3-C10 ketone (preferably a C3-C6 ketone, such as acetone, methyl ethyl ketone), a C2-C12 ester (preferably a C3-C8 ester, such as dimethyl acetate, diethyl acetate, etc.) solvent; the solvent content is such that the solids content of the tackifying resin (D) after reaction satisfies a concentration range of 5 to 50wt.%, preferably 10 to 48 wt.%, more preferably 15 to 45 wt.%, more preferably 20 to 43 wt.%, more preferably 25 to 40 wt.%, more preferably 28 to 38 wt.%.

The radical initiator in the schemes 1 and 2 is a thermal initiation radical initiator, such as 2,2' -Azobisisobutyronitrile (AIBN), 2,2' -azobis (2,4-dimethylvaleronitrile), 2,2' -azobis (4-methoxy-2,4-dimethylvaleronitrile), and other azo compounds; one or more peroxide initiators such as benzoyl peroxide and lauroyl peroxide, preferably azo compounds, more preferably AIBN as an initiator; the content of the radical initiator is 0.1 to 10wt.%, more preferably 0.1 to 5wt.%, and still more preferably 0.5 to 4 wt.% based on the content of the synthetic monomers. The initiator may be present in particular embodiments in an amount of 0.1, 1,2, 3,4, 5, 6, 8 or 10 weight percent based on the total amount of monomers synthesized.

Preferably, in the embodiments 1 and 2, the chain transfer agent is a mercaptan such as n-hexylmercaptan, n-octylmercaptan, n-dodecylmercaptan, thioglycolic acid, or the like; diisopropyl xanthogen disulfide; alpha-methylstyrene dimer; one or more of tetraethyl thiuram disulfide and the like, and the amount of the chain transfer agent is 0.1 to 10 percent by weight, preferably 0.4 to 8 percent by weight, based on the total amount of the synthesized monomers. In particular embodiments the chain transfer agent may be present in an amount of 0.1, 0.3, 0.4, 1,2, 3,4, 6, 8 or 10wt% based on the total amount of monomers synthesized.

In a further optimized scheme, in the scheme 1 and the scheme 2, the content of the catalyst in the step (2) or (2') accounts for 0.01 to 5wt%, further 0.05 to 1.0wt%, for example 0.1 to 0.5wt% of the weight of the reactants; the catalytic reaction temperature is 60-120 ℃, and the reaction time is 8-12 h. The catalyst content may be 0.01, 0.1, 1,2, 3 or 5wt% of the weight of the reactants in specific embodiments; the catalytic reaction temperature is 60, 70, 80, 100, 110 or 120 ℃, and the reaction time is 8, 9, 10, 11 or 12h.

The molecular chain end of the resin prepolymer has at least 2 UV free-radical curable functional groups. The resin prepolymer is obtained by solution free radical polymerization and functional group modification, and contains a photocuring functional group.

Scheme 1 of the invention is to introduce carboxyl into the main chain of tackifying resin, and utilize the combination reaction of carboxyl and epoxy-containing (methyl) acrylate functional group in the second step, so as to introduce the photo-curable reaction functional group on the main chain, scheme 2 is to introduce hydroxyl into the main chain of tackifying resin, and then utilize the reaction of hydroxyl and compound containing isocyanate and (methyl) acrylate monomer, so as to introduce the photo-curable functional group on tackifying resin, the modification principle of both is different, but the photo-curable functional group is introduced on the main chain of radical polymer.

Further, the monomer compound of component (B), which is a diluting reactive monomer compound, is selected from monomer compounds containing one or more acrylic acid or acrylic acid-derived functional groups, vinyl ether functional groups.

The component (A) with at least 2 functional groups capable of curing by UV free radicals at the molecular chain end is selected as the main component of the UV adhesive, if the content of the functional groups is too low, the capability of participating in the reaction is low, and the curing is insufficient, or the oxygen inhibition is serious after the curing, the strength is insufficient, and the like. The monomer compound of component (B) functions to control viscosity, control glass transition temperature Tg of the cured product, hardness, control ingredients from the viewpoint of cost, and improve adhesion. Other additives have the functions of controlling leveling property, defoaming property, fluorescence indication or preventing mould and the like. The initiator generates free radicals in illumination, and changes in adhesion and surface properties and adhesive properties can be achieved after the component (D) is introduced.

The invention introduces the photo-curable functional group by different modification means, improves the state after bonding and curing and has good effect. The traditional UV curing adhesive contains prepolymer which is generally polyurethane acrylate prepolymer, diluent monomer B and photoinitiator, the invention introduces the prepolymer containing photocuring functional group to free radical polymerization tackifying prepolymer, and the traditional acrylic resin does not contain the functional group.

In a preferred embodiment, the resin prepolymer (a) has at least 2 UV free-radical curable acrylic functional groups at the molecular chain end, specifically one or more of a polyurethane acrylic prepolymer, an epoxy acrylic prepolymer, and a polyester acrylic prepolymer, preferably a polyurethane acrylic prepolymer. The urethane acrylic resin may be CN996, CN8003, CN8888, CN9014, CN9021, etc. produced by sartomer, EB4883, EB8402, EB8210, EB8702, etc. produced by Allnex; as the epoxy acrylic resin, CN115, CN118 and the like available from Sartomer, EB3700, EB3703, EB3708 and the like available from Allnex; the polyester acrylic resin may be CN704, CN790, CN2283, CN2281, etc. produced by Sartomar, EB411, EB571, EB853, etc. produced by Allnex. These prepolymers are well defined in radiation curable materials and their use, chemical industry publishers, 10 months 2003) and can also be prepared according to methods known in the art, for example, polyurethane acrylic prepolymers using a polyol reacted with a polyisocyanate, an isocyanate excess, and then reacted with a hydroxyl-containing acrylic end-capping monomer such as hydroxyethyl acrylate to introduce acrylic functionality.

The polyurethane acrylic prepolymer preferably has a functionality of 2 to 3.

In a further preferred embodiment, the monomer compound (B) is a monomer compound containing one or more acrylic or acrylic-derived functional groups, vinyl ether functional groups, i.e. a monomer compound (B) containing a single functional group, containing a bifunctional group or containing a multifunctional group, which may also be referred to as (B1), (B2) and (B3), respectively.

The monomer compound (B) having a single functional group, i.e., (B1), is, for example, one or more of methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2- (2-ethoxyethoxy) ethyl acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, isodecyl (meth) acrylate, isooctyl (meth) acrylate, tetrahydrofuran (meth) acrylate, 2-methyl-2-acrylic acid-3,3,5-trimethylcyclohexyl ester, cyclic Trimethylolpropane Formal Acrylate (CTFA), dicyclopentenylmethacrylate, N-dimethylacrylamide, N-vinylcaprolactam, 4-acryloylmorpholine, vinyl ether, N-propyl vinyl ether, and the like; preferably one or more of isobornyl acrylate, dicyclopentenyl methacrylate and N, N-dimethylacrylamide.

The bifunctional monomer compound (B), i.e., (B2), is one or more selected from the group consisting of hexanediol diacrylate, ethylene glycol dimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, ethylene glycol ethoxylated bisphenol A dimethacrylate, propoxylated neopentyl glycol diacrylate, cyclohexanedimethanol diacrylate, tricyclodecane dimethanol diacrylate, diethylene glycol divinyl ether, and the like.

The polyfunctional monomer compound (B) (i.e., (B3)) is one or more selected from trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the like.

Further preferably, the photoinitiator (C) is a free radical photoinitiator with high activity between 200 and 400 nm; preferably, the photoinitiator is a photoinitiator comprising Norrish type I and/or Norrish type II and may comprise one or more of benzoin and derivatives thereof, benzil ketals, phenylacetyl derivatives, benzophenone derivatives, acetophenone derivatives, diethoxyacetophenone or thioxanthone.

The photoinitiator includes Irgacure and Darocue series initiators from Ciba, such as 1-hydroxycyclohexyl phenyl ketone (Irgacure 184), 2-methyl-4' - (methylthio) -2-morpholinobenzophenone (Irgacure 907), 2,2-dimethoxy-phenyl ethanone (Irgacure 651), bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide (Irgacure 819), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone (Irgacure 369), photoinitiator Irgacure 1700, photoinitiator Irgacure 500, 2-hydroxy-2-methyl-1-phenyl-1-propanone (Darocue 1173), and the like; other initiators such as one or more of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO), ethyl phenyl (2,4,6-trimethylbenzoyl) phosphonate (TPO-L), 2,2-Diethoxyacetophenone (DEAP), derivatives of 2-hydroxy-2-methyl-1-propanone-1- (4-C10-13-alkylbenzene) (Tego Photonitiator A18, a. Winning company), and the like.

In an optimized scheme, the photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenyl-1-acetone (Darocue 1173), 2,2-Diethoxyacetophenone (DEAP), (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO), and phenyl (2,4,6-trimethylbenzoyl) ethyl phosphonate (TPO-L).

The other auxiliary agents comprise one or more of a photo-thermal stabilizer, an adhesion promoter, a fluorescent indicator, a thixotropic agent, a pigment and an anti-mildew auxiliary agent. The photo-thermal stabilizer may be, for example, one or more of hydroquinone, p-hydroxyanisole, 2,4,6-tri-t-butylphenol, etc., and the adhesion promoter may be, for example, one or more of a silane coupling agent containing acryloxy, epoxy, isocyanate, etc., such as (methacryloxy) propyltrimethoxysilane, 3- (2,3-epoxypropoxy) propyltrimethoxysilane, isocyanatopropyltrimethoxysilane, the fluorescent indicator can use one or more of 2,2- (4,4-distyryl) bisbenzoxazole (fluorescent whitening agent OB-1), 4,4 '-bis (2,2-distyryl) -1,1' -biphenyl, bistriazine aminostilbenes fluorescent whitening agent and the like, the thixotropic agent can use one or more of fumed silica, organobentonite and the like, the pigment can use one or more of titanium dioxide, phthalocyanine blue, oil soluble blue and the like, and the anti-mildew auxiliary agent can use one or more of 1,2-benzisothiazole-3-one, 2-octyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one and the like.

The invention also provides a preparation method of the UV curing adhesive, which comprises the following steps:

(1) The tackifying resin is obtained by scheme 1 or scheme 2 below:

scheme 1

Step (1): polymerizing a carboxyl group-containing radical polymerizable monomer (I) and a radical comonomer (II) free of free carboxyl groups and hydroxyl groups in a solvent under the action of a radical initiator, controlling the molecular weight of the product by using a chain transfer agent, and obtaining a product obtained from a radical polymer P1;

step (2): reacting the free radical polymer P1 in the step (1) with an epoxy group-containing unsaturated compound with free radical polymerization under the action of a catalyst, and evaporating a solvent to obtain a tackifying resin (D); wherein, carboxyl on the lateral group of the P1 molecular chain is converted into a functional group with photocuring free radical polymerization property;

scheme 2

Step (1'): polymerizing a hydroxyl-containing radical polymerizable monomer (III) with a radical comonomer (II) free of free carboxyl and hydroxyl groups in a solvent under the action of a radical initiator, controlling the molecular weight of the product using a chain transfer agent, and obtaining a product obtained from the radical polymer M1;

step (2'): reacting the free radical polymer M1 obtained in the step (1') with a compound which has free radical polymerization and contains isocyanate functional groups under the action of a catalyst, converting carboxyl on a lateral group of a P1 molecular chain into a functional group with photocuring free radical polymerization, and evaporating a solvent to obtain tackifying resin (D); wherein, hydroxyl on the lateral group of the molecular chain of M1 is converted into a functional group with photocuring free radical polymerization,

(2) Putting the components (A), (B), (C), (D) and (E) into a mixing device such as a planetary stirring kettle, and uniformly stirring and mixing (for example, the stirring speed is 30-240 r/min, and the stirring time is 0.5-4 h);

optionally, (3) removing bubbles in vacuum and packaging, wherein the vacuum degree of vacuum defoaming is less than or equal to-0.085 MPa.

Wherein, various parameters of raw materials, raw material consumption, reaction conditions and the like for preparing the tackifying resin are the same as those mentioned above.

In this application, "optional" and "optionally" mean the presence or absence of the substance or step to be followed.

Advantages and effects of the invention

In the invention, (D) is tackifying resin containing functional groups of light-curable reaction, free radical cured acrylic resin can provide tackifying resin with adhesive force, and after the light-curable functional groups are introduced to the main chain of the tackifying resin, the tackifying resin also participates in the reaction during illumination, thereby improving the surface oxygen resistance and polymerization inhibition capability, and further improving the excellent oxygen resistance and polymerization inhibition capability, adhesive force and toughness of the UV curing adhesive.

The UV curing adhesive is suitable for various base materials such as metal and plastic, the surface oxygen inhibition phenomenon of the UV curing acrylic adhesive can be well improved after the tackifying resin is introduced into the UV curing adhesive through the specific tackifying resin (D) containing the photocuring functional group obtained by solution free radical polymerization and functional group modification, the cured adhesive has excellent adhesive force and toughness under the conditions of high-low temperature circulation and high-temperature high-humidity aging, the adhesive force is stable after reliability test, and the surface cracking phenomenon does not occur; the preparation method is simple, easy to operate and low in cost.

Detailed Description

The present invention is further illustrated by the following examples. In the present application, parts are calculated as parts by weight, unless otherwise specified.

Example 1

In a 4-neck flask having a condenser, a stirrer and a nitrogen-introducing device, 3 parts of thermal initiator AIBN, 4 parts of tetraethyl thiuram disulfide (chain transfer agent, molecular weight control agent) and 300 parts of butyl acetate were charged as a solvent. Then, 23 parts of methacrylic acid (as reactive monomer I), 32 parts of butyl methacrylate (as reactive monomer II), 35 parts of benzyl methacrylate (as reactive monomer II), and 10 parts of dicyclopentadiene acrylate (as reactive monomer II) were charged in this order. After nitrogen replacement, nitrogen gas was continuously introduced, the reaction temperature was slowly raised to 80 ℃ by stirring, and the reaction was maintained at this temperature for 4 hours, and then the reaction temperature was slowly raised to 100 ℃, and 2 parts of thermal initiator AIBN was further added, and the reaction was maintained at this temperature for 1 hour, to obtain a carboxyl group-containing radical polymer solution P1.

Adding 1.1 parts of tetrabutylammonium bromide into the prepared carboxyl-containing free radical polymer solution P1, adding 0.05 part of P-hydroxyanisole as a polymerization inhibitor in order to avoid self-polymerization of the prepolymer after introducing acrylic groups, then adding 16 parts by weight of glycidyl methacrylate to react with carboxyl in the P1, keeping the reaction for 10 hours at 90 ℃, removing the solvent under reduced pressure at 120 ℃ and the vacuum degree of less than or equal to-0.085 MPa, cooling the product and crushing to obtain the special tackifying resin D-1 containing the photocuring functional groups.

Example 2

Similarly to example 1, except for using 25 parts of methacrylic acid (as reactive monomer I), 30 parts of butyl methacrylate (as reactive monomer II), 33 parts of benzyl methacrylate (as reactive monomer II), and 12 parts of dicyclopentadiene acrylate (as reactive monomer II), tackifier resin D-2 was obtained.

Example 3

Similar to example 1, except that 18 parts by weight of 3,4-epoxycyclohexylmethacrylate were used instead of 16 parts by weight of glycidyl methacrylate, tackifying resin D-3.

Example 4

Similarly to example 1, except for using 20 parts of methacrylic acid (as reactive monomer I), 30 parts of propyl methacrylate (as reactive monomer II), 35 parts of phenyl methacrylate (as reactive monomer II) and 15 parts of dicyclopentadiene acrylate (as reactive monomer II), a tackifier resin D-4 was obtained.

Example 5

In a 4-neck flask having a condenser, a stirring device and a nitrogen gas introducing device, 3 parts of thermal initiator AIBN, 4 parts of tetraethyl thiuram disulfide (chain transfer agent, molecular weight control agent) and 300 parts of butyl acetate were charged as a solvent. Then, 23 parts of hydroxyethyl acrylate (as the reactive monomer III), 32 parts of butyl methacrylate (as the reactive monomer II), 35 parts of benzyl methacrylate (as the reactive monomer II) and 10 parts of dicyclopentadiene acrylate (as the reactive monomer II) were charged in this order. After nitrogen replacement, nitrogen gas was continuously introduced, the reaction temperature was slowly raised to 80 ℃ by stirring, and the reaction was maintained at this temperature for 4 hours, and then the reaction temperature was slowly raised to 100 ℃, and 2 parts of thermal initiator AIBN was further added, and the reaction was maintained at this temperature for 1 hour, to obtain a hydroxyl group-containing radical polymer solution M1.

Adding 0.05 part of dibutyltin dilaurate into the hydroxyl-containing free radical polymer solution M1 to avoid self-polymerization of the prepolymer after introducing acrylic groups, adding 0.05 part of p-hydroxyanisole as a polymerization inhibitor, then adding 12 parts by weight of 3-methacryloyloxyethyl isocyanate (MOI) to react with hydroxyl groups in the M1, keeping the reaction for 10 hours at 90 ℃, removing the solvent under reduced pressure at 120 ℃ and the vacuum degree of less than or equal to-0.085 MPa, cooling the product and crushing to obtain the specific tackifying resin D-5 containing the photocuring functional groups.

Example 6

A specific tackifying resin D-6 was obtained in a manner substantially similar to example 5, except that 3-hydroxypropyl methacrylate was used instead of hydroxyethyl acrylate.

Example 7

Similar to example 5, except that 2-acryloxyethyl isocyanate (AOI) was used in place of 3-methacryloxyethyl isocyanate (MOI), a specific tackifying resin D-7 was obtained.

Example 8

Similar to example 5, except that 20 parts of hydroxyethyl methacrylate (as the reactive monomer III), 28 parts of propyl methacrylate (as the reactive monomer II), 32 parts of phenyl methacrylate (as the reactive monomer II), and 20 parts of dicyclopentadiene acrylate (as the reactive monomer II) were used, specific tackifier resin D-8 was obtained.

Example 9

30 parts of commercially available polyurethane acrylic resin CN8888 (Satomer as prepolymer A), 30 parts of isobornyl methacrylate (diluent B1), 15 parts of N, N-dimethylacrylamide (diluent B2), 3 parts of photoinitiator TPO (photoinitiator C), 20 parts of tackifying resin D-1 (tackifying resin D prepared in scheme 1) and 2 parts of silicone oil treated fumed silica (Areosil R208, evonik as thixotropic agent) are sequentially added into a planetary stirring kettle, and stirred for 2 hours at the rotating speed of 120R/min under the vacuum degree of less than or equal to-0.085 MPa to obtain the uniform UV curing adhesive 1.

Example 10

35 parts of a commercially available epoxy acrylic resin Sartomer CN115 (Satomer as prepolymer A), 25 parts of isobornyl methacrylate (diluent B1), 15 parts of N, N-dimethylacrylamide (diluent B2), 3 parts of a photoinitiator TPO (photoinitiator C), 20 parts of a tackifying resin D-2 (tackifying resin D, prepared in scheme 1) and 2 parts of fumed silica treated by silicone oil (Areosil R208, evonik as a thixotropic agent) are sequentially added into a planetary stirring kettle, and stirred for 2 hours at the rotating speed of 120R/min under the vacuum degree of less than or equal to-0.085 MPa to obtain the uniform UV curing adhesive 2.

Example 11

65 parts of a commercially available polyester acrylic resin Sartomar CN704 (Satomer as prepolymer A), 3 parts of a photoinitiator TPO (photoinitiator C), 30 parts of a tackifying resin D-3 (tackifying resin D, prepared according to scheme 1) and 2 parts of fumed silica (Areosil R208, evonik as a thixotropic agent) subjected to silicone oil treatment are sequentially added into a planetary stirring kettle, and stirred at the rotating speed of 120R/min for 2 hours under the vacuum degree of less than or equal to-0.085 MPa to obtain the uniform UV curing adhesive 3.

Example 12

Sequentially adding 30 parts of trimethylolpropane triacrylate, 30 parts of isobornyl methacrylate (a diluent monomer B1), 15 parts of N, N-dimethylacrylamide (a diluent monomer B2), 3 parts of photoinitiator TPO (a photoinitiator C), 20 parts of tackifying resin D-1 (tackifying resin D, prepared in scheme 1) and 2 parts of silicone oil treated fumed silica (Areosil R208, evonik serving as a thixotropic agent) into a planetary stirring kettle, and stirring for 2 hours at the rotating speed of 120R/min under the vacuum degree of less than or equal to-0.085 MPa to obtain the uniform UV curing adhesive 4.

Example 13

30 parts of commercially available polyurethane acrylic resin CN8888 (Satomer as prepolymer A), 30 parts of isobornyl methacrylate (diluent B1), 15 parts of N, N-dimethylacrylamide (diluent B2), 3 parts of photoinitiator TPO (photoinitiator C), 20 parts of tackifying resin D-5 (tackifying resin D prepared by the second method) and 2 parts of silicone oil-treated fumed silica (Areosil R208, evonik as thixotropic agent) are sequentially added into a planetary stirring kettle, and stirred for 2 hours at the rotating speed of 20Hz and the vacuum degree of less than or equal to-0.085 MPa to obtain the uniform UV curing adhesive 5.

Example 14

30 parts of commercially available polyurethane acrylic resin Sartomer CN115 (Satomer as prepolymer A), 30 parts of isobornyl methacrylate (diluent B1), 15 parts of N, N-dimethylacrylamide (diluent B2), 3 parts of photoinitiator TPO (photoinitiator C), 20 parts of tackifying resin D-6 (tackifying resin D, prepared according to scheme 2) and 2 parts of silicone oil-treated fumed silica (Areosil R208, evonik as thixotropic agent) are sequentially added into a planetary stirring kettle, and stirred for 2 hours at the rotating speed of 20Hz and the vacuum degree of less than or equal to-0.085 MPa to obtain the uniform UV curing adhesive 6.

Example 15

75 parts of a commercially available polyurethane acrylic resin Sartomar CN704 (Satomer as prepolymer A), 3 parts of a photoinitiator TPO (photoinitiator C), 20 parts of a tackifying resin D-7 (tackifying resin D, prepared according to scheme 2) and 2 parts of silicone oil-treated fumed silica (Areosil R208, evonik as a thixotropic agent) are sequentially added into a planetary stirring kettle, and stirred at a rotation speed of 20Hz and a vacuum degree of less than or equal to-0.085 MPa for 2 hours to obtain the uniform UV curing adhesive 7.

Example 18

60 parts of isobornyl methacrylate (a diluent monomer B1), 15 parts of N, N-dimethylacrylamide (a diluent monomer B2), 3 parts of photoinitiator TPO (photoinitiator C), 20 parts of tackifying resin D-7 (tackifying resin D, prepared according to scheme 2) and 2 parts of fumed silica (Areosil R208, evonik, which is used as a thixotropic agent) are sequentially added into a planetary stirring kettle, and the mixture is stirred for 2 hours at the rotating speed of 20Hz and the vacuum degree of less than or equal to-0.085 MPa to obtain the uniform UV curing adhesive 8. Comparative example 1 (commercially available acrylic free radical Polymer as D)

30 parts of a commercially available urethane acrylic resin CN8888 (Satomer as prepolymer A), 30 parts of isobornyl methacrylate (diluent B1), 15 parts of N, N-dimethylacrylamide (diluent B2), 3 parts of a photoinitiator TPO (photoinitiator C), 20 parts of a commercially available thermoplastic acrylic resin (Mitsubishi BR-117, a tackifying resin D not according to the invention) and 2 parts of silicone oil-treated fumed silica (Areosil R208, evonik as a thixotropic agent) were sequentially added to a planetary stirring kettle, and stirred at a rotation speed of 20Hz at a vacuum degree of-0.085 MPa for 2 hours to obtain a uniform UV-curable adhesive 3.

COMPARATIVE EXAMPLE 2 (without D)

50 parts of a commercially available polyurethane acrylic resin CN8888 (Satomer as prepolymer A), 30 parts of isobornyl methacrylate (diluent B1), 15 parts of N, N-dimethylacrylamide (diluent B2), 3 parts of a photoinitiator TPO (photoinitiator C) and 2 parts of fumed silica (Areosil R208, evonik as a thixotropic agent) which is treated by silicone oil are sequentially added into a planetary stirring kettle, and stirred for 2 hours at the rotating speed of 20Hz and the vacuum degree of less than or equal to-0.085 MPa to obtain the uniform UV curing adhesive 4.

The UV curing prepared in each of examples 9 and 13 and comparative examples 1-2 was cured under a UV-LED lamp source with an irradiation intensity of 1500mJ/cm2 and a dominant wavelength of 365nm in a common air atmosphere, and the properties of the cured adhesive are shown in Table 1:

TABLE 1 comparison of the Properties of the UV-curable adhesives in the examples and comparative examples

Wherein, the surface dryness is whether the surface of the cured adhesive is sticky or not by touching with a finger. The initial shear strength is the tensile shear strength of Polycarbonate (PC) on metallic aluminum material tested according to the national standard GB/T7124.

The high temperature and high humidity aging conditions were those obtained by aging the cured adhesive sample at 85 ℃ RH (commonly referred to as "Bi 85") for 1000 hours.

The high-low temperature cyclic aging condition is that an adhesive sample is aged at the temperature of-40 ℃ to 125 ℃, the temperature rising and falling speed is 11 ℃/min, the heat preservation time is 30min at the temperature of-40 ℃ and 125 ℃, and the structure is aged for 1000h under the temperature cyclic condition.

As can be seen from the comparison of the performances of the UV curing adhesives prepared in the embodiment and the comparative example, the modified tackifying resin (D) in the UV curing adhesive in the components of the invention can effectively improve the surface oxygen inhibition phenomenon of the cured product, and the performances of the UV curing adhesive are basically kept unchanged after high-temperature high-humidity and high-low temperature cyclic aging. The common commercial thermoplastic acrylic resin can also solve the surface oxygen inhibition phenomenon of the UV curing adhesive, but the adhesive force and the toughness of the UV curing adhesive are deteriorated to different degrees after high-low temperature aging and high-temperature high-humidity aging.

While the foregoing shows and describes the fundamental principles and principal features of the invention, together with the advantages thereof, the foregoing embodiments and description are illustrative only of the principles of the invention, and various changes and modifications can be made therein without departing from the spirit and scope of the invention, which will fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (31)

1. A UV curable adhesive with excellent adhesion, comprising (a) a resin prepolymer having at least 2 UV free-radically curable functional groups at the molecular chain ends, (B) a monomer compound having a single or multiple free-radically photocurable functional groups, (C) a photoinitiator, (D) a tackifying resin, (E) optionally other auxiliaries;

the amount of the resin prepolymer (A) is 0 to 90wt.% based on the total mass of (A), (B), (C) and (D); the dosage of the monomer compound (B) is 0-70wt%; the dosage of the initiator (C) is 0.1 to 10wt%; the dosage of the tackifying resin (D) is 5 to 50wt%; the other auxiliaries (E) are used in amounts of from 0 to 10 parts by weight, based on 100 parts by weight of the composition of (A), (B), (C) and (D), and not both (A) and (B) can be 0% by weight;

the resin prepolymer (A) is one or more of polyurethane acrylic resin prepolymer, epoxy acrylic resin prepolymer and polyester acrylic resin prepolymer;

the tackifying resin (D) is obtained by the following scheme 1:

step (1): polymerizing a carboxyl group-containing radical polymerizable monomer (I) and a radical comonomer (II) free of free carboxyl groups and hydroxyl groups in a solvent under the action of a radical initiator, controlling the molecular weight of the product by using a chain transfer agent, and obtaining a product obtained from a radical polymer P1;

step (2): reacting the free radical polymer P1 in the step (1) with an unsaturated compound containing an epoxy group and having free radical polymerization, and evaporating the solvent to obtain a tackifying resin (D);

or by scheme 2 below:

step (1'): polymerizing a hydroxyl-containing radical polymerizable monomer (III) with a radical comonomer (II) free of free carboxyl and hydroxyl groups in a solvent under the action of a radical initiator, controlling the molecular weight of the product using a chain transfer agent, and obtaining a product obtained from the radical polymer M1;

step (2'): reacting the free radical polymer M1 obtained in the step (1') with a compound which has free radical polymerization and contains isocyanate functional groups, and evaporating the solvent to obtain tackifying resin (D);

wherein, the carboxyl-containing free radical polymerizable monomer (I) in the step (1) is selected from one or more of unsaturated carboxylic acid acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid;

the comonomer (II) used in the above schemes 1 and 2 is one or more selected from alkyl (meth) acrylate, cycloalkyl (meth) acrylate, aryl (meth) acrylate, aralkyl (meth) acrylate, vinyl aromatic compound, conjugated diene;

in the step (1') of scheme 2, the hydroxyl group-containing radically polymerizable monomer (III) is one or more selected from the group consisting of a (meth) acrylate having a hydroxyl group, a (meth) acrylate having a phenolic hydroxyl group, and hydroxystyrene.

2. The UV-curable adhesive according to claim 1, characterized in that:

the amount of the resin prepolymer (A) is 5-80wt% based on the total mass of (A), (B), (C) and (D); the amount of the monomer compound (B) is 5-60wt%; the dosage of the initiator (C) is 0.2 to 9 weight percent; the amount of the tackifying resin (D) is 6 to 45 weight percent; the other auxiliaries (E) are used in amounts of from 0 to 9 parts by weight, based on 100 parts by weight of the composition of (A), (B), (C) and (D).

3. The UV-curable adhesive according to claim 1, characterized in that:

the amount of the resin prepolymer (A) is 8-70wt% based on the total mass of (A), (B), (C) and (D); the dosage of the monomer compound (B) is 20 to 50wt.%; the dosage of the initiator (C) is 0.5 to 8 weight percent; the amount of the tackifying resin (D) is 7-40wt%; the other auxiliaries (E) are used in amounts of from 0 to 8 parts by weight, based on 100 parts by weight of the composition of (A), (B), (C) and (D).

4. The UV-curable adhesive according to claim 1, characterized in that:

the amount of the resin prepolymer (A) is 9-60wt% based on the total mass of (A), (B), (C) and (D); the amount of the monomer compound (B) is 25-45wt%; the dosage of the initiator (C) is 0.8 to 7 weight percent; the amount of the tackifying resin (D) is 8 to 35 weight percent; the other auxiliaries (E) are used in amounts of from 0 to 7 parts by weight, based on 100 parts by weight of the composition of (A), (B), (C) and (D).

5. The UV-curable adhesive according to claim 1, characterized in that:

the resin prepolymer (a) is used in an amount of 10 to 50wt.%, based on the total mass of (a), (B), (C) and (D); the amount of the monomer compound (B) is 30-40wt%; the amount of the initiator (C) is 1-5wt.%; the amount of said tackifying resin (D) is from 10 to 30wt.%; the other auxiliaries (E) are used in amounts of from 0 to 6 parts by weight, based on 100 parts by weight of the composition of (A), (B), (C) and (D).

6. The UV-curable adhesive according to claim 1, characterized in that: the proportion of the carboxyl-containing polymerizable free radical monomer (I) in the total amount of the reaction monomers is 3 to 50wt%; the using amount of the comonomer (II) accounts for 50-97wt% of the total amount of the reaction monomers, and the total amount of the reaction monomers comprises the sum of the carboxyl-containing polymerizable free radical monomer (I) and the comonomer (II).

7. The UV-curable adhesive according to claim 6, characterized in that: the proportion of the carboxyl-containing polymerizable free radical monomer (I) in the total amount of the reaction monomers is 5 to 30wt%; the amount of the comonomer (II) accounts for 70-95 wt% of the total amount of the reaction monomers.

8. The UV-curable adhesive according to claim 7, characterized in that: the proportion of the carboxyl-containing polymerizable free radical monomer (I) in the total amount of the reaction monomers is 8 to 25wt%; the using amount of the comonomer (II) accounts for 75 to 92wt% of the total amount of the reaction monomers.

9. The UV-curable adhesive according to claim 8, wherein: the proportion of the carboxyl-containing polymerizable free radical monomer (I) in the total amount of the reaction monomers is 10-20wt%; the usage range of the comonomer (II) in the total amount of the reaction monomers is 80-90wt%.

10. The UV-curable adhesive according to claim 6, characterized in that: the carboxyl group-containing radically polymerizable monomer (I) in step (1) is selected from acrylic acid or methacrylic acid.

11. The UV-curable adhesive according to any one of claims 1 to 10, characterized in that: in the above scheme 1, the unsaturated compound containing an epoxy group and having a radical polymerization property is one or more selected from glycidyl (meth) acrylate, 3,4-epoxycyclohexyl methacrylate, and 4-vinylbenzyl glycidyl ether, and the step (2) satisfies that the ratio of the molar amount of the epoxy functional group to the molar amount of the carboxyl group in the step (1) is 0.05 to 0.99, or the unsaturated compound containing an epoxy group and having a radical polymerization property accounts for 5 to 25wt% of the total amount of the reaction monomers, and the total amount of the reaction monomers includes the sum of the polymerizable radical monomer (I) containing a carboxyl group and the comonomer (II).

12. The UV-curable adhesive according to claim 11, characterized in that: and (2) the ratio of the molar quantity of the epoxy functional group to the molar quantity of the carboxyl group in the step (1) is 0.1 to 0.9, or the unsaturated compound containing the epoxy group and having free radical polymerization accounts for 7 to 22wt% of the total amount of the reaction monomers.

13. The UV-curable adhesive according to claim 11, wherein: and (2) the molar weight of the epoxy functional group and the molar weight of the carboxyl in the step (1) are in a ratio of 0.3 to 0.7, or an unsaturated compound containing an epoxy group and having free radical polymerization accounts for 10 to 20wt% of the total amount of the reaction monomers.

14. The UV-curable adhesive according to claim 11, characterized in that: and (2) the ratio of the molar quantity of the epoxy functional group to the molar quantity of the carboxyl group in the step (1) is 0.4 to 0.6, or the unsaturated compound containing the epoxy group and having free radical polymerization accounts for 12 to 18wt% of the total amount of the reaction monomers.

15. The UV-curable adhesive according to any one of claims 1 to 10, characterized in that: the proportion of the hydroxyl-containing polymerizable free radical monomer (III) in the total amount of the reaction monomers in the scheme 2 is 3 to 50wt%; the amount of the comonomer (II) is 50 to 97wt% of the total amount of the reactive monomers in the scheme 2, and the total amount of the monomers comprises the sum of the hydroxyl-containing polymerizable free radical monomer (III) and the comonomer (II).

16. The UV-curable adhesive according to claim 15, characterized in that: in the step (1') of scheme 2, the hydroxyl group-containing radically polymerizable monomer (III) is one or more selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and p-hydroxystyrene.

17. The UV-curable adhesive according to claim 15, wherein: the proportion of the polymerizable free radical monomer (III) containing hydroxyl to the total amount of the reaction monomers in the scheme 2 is 5 to 30wt%; the amount of the comonomer (II) accounts for 70-95 wt% of the total amount of the reaction monomers in the scheme 2.

18. The UV-curable adhesive according to claim 15, wherein: the proportion of the polymerizable free radical monomer (III) containing hydroxyl in the total amount of the reaction monomers in the scheme 2 is 8 to 25wt%; the amount of the comonomer (II) in the total amount of the reaction monomers in the scheme 2 is 75 to 92wt%.

19. The UV-curable adhesive according to claim 15, wherein: the proportion of the hydroxyl group-containing polymerizable radical monomer (III) to the total amount of the reactive monomers in scheme 2 is 10 to 20wt%; the amount of the comonomer (II) in the total amount of the reaction monomers in the scheme 2 is 80 to 90wt%.

20. The UV-curable adhesive according to claim 15, characterized in that: in the scheme 2, the compound containing isocyanate functional group and having free radical polymerization property is one or more of 2-acryloyloxyethyl isocyanate (AOI), 2-methacryloyloxyethyl isocyanate (MOI), and 2- [2- (methacryloyloxy) ethoxy ] ethyl isocyanate (MOI-EG); in the step (2 '), the ratio of the molar quantity of the isocyanate to the molar quantity of the hydroxyl in the step (1') is 0.05 to 0.99, or the unsaturated compound with free radical polymerization and containing an epoxy group accounts for 5 to 25wt% of the total amount of the reaction monomers, and the total amount of the reaction monomers comprises the sum of the polymerizable free radical monomer (I) containing a carboxyl group and the comonomer (II).

21. The UV-curable adhesive according to claim 20, characterized in that: in the step (2 '), the ratio of the molar quantity of the isocyanate group to the molar quantity of the hydroxyl group in the step (1') is 0.1 to 0.9, or the unsaturated compound containing an epoxy group and having free radical polymerization accounts for 7 to 22wt% of the total amount of the reaction monomers.

22. The UV-curable adhesive according to claim 21, characterized in that: in the step (2 '), the ratio of the molar quantity of the isocyanate to the molar quantity of the hydroxyl in the step (1') is 0.2 to 0.8, or 8 to 20wt% of unsaturated compound containing epoxy group and having free radical polymerization in the total amount of the reaction monomer is satisfied.

23. The UV-curable adhesive according to claim 22, characterized in that: in the step (2 '), the ratio of the molar quantity of the isocyanate group to the molar quantity of the hydroxyl group in the step (1') is 0.3 to 0.7, or 10 to 18wt% of the unsaturated compound containing an epoxy group having radical polymerization based on the total amount of the reaction monomers.

24. The UV-curable adhesive according to any one of claims 1 to 10, characterized in that: the comonomer (II) used in the schemes 1 and 2 is one or more selected from the group consisting of methyl (meth) propionate, dicyclopentadiene acrylate, phenyl methacrylate, benzyl methacrylate, styrene and 1,3-butadiene.

25. The UV-curable adhesive according to any one of claims 1 to 10, characterized in that: the solvent in the scheme 1 and the scheme 2 is one or more of C1-C8 organic alcohols, C2-C14 glycol ethers, C3-C10 ketones and C2-C12 ester solvents; the solvent content is such that the solid content of the tackifying resin (D) after the reaction satisfies the concentration range of 5 to 50wt.%; and/or

The free radical initiator in scheme 1 and scheme 2 is a thermally initiated free radical initiator; or one or more peroxide initiators selected from benzoyl peroxide and lauroyl peroxide; the amount of the initiator accounts for 0.1 to 10wt% of the total amount of the synthetic monomer; and/or

In the schemes 1 and 2, the chain transfer agent is n-hexylmercaptan, n-octylmercaptan, n-dodecylmercaptan, thioglycolic acid, and diisopropyl xanthogen disulfide; alpha-methylstyrene dimer; one or more of tetraethyl thiuram disulfide and the content of the chain transfer agent accounts for 0.1 to 10wt% of the total amount of the synthesized monomer.

26. The UV-curable adhesive according to any one of claims 1 to 10, characterized in that: in the schemes 1 and 2, the content of the catalyst in the step (2) or (2') accounts for 0.01 to 5wt% of the weight of the reactants; the catalytic reaction temperature is 60 to 120 ℃, and the reaction time is 8 to 12h.

27. The UV-curable adhesive according to any one of claims 1 to 10, wherein: the resin prepolymer (a) has at least 2 UV free radical curable acrylic functional groups at the molecular chain ends; and/or

The monomer compound (B) is a compound containing one or more acrylic acid or acrylic acid-derived functional groups, vinyl ether functional groups.

28. The UV-curable adhesive according to claim 1, characterized in that: the monomer compound (B) having a single functional group, i.e., (B1), is one or more of methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2- (2-ethoxyethoxy) ethyl acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, isodecyl (meth) acrylate, isooctyl (meth) acrylate, tetrahydrofuryl (meth) acrylate, 2-methyl-2-acrylic acid-3,3,5-trimethylcyclohexyl ester, cyclic Trimethylolpropane Formal Acrylate (CTFA), dicyclopentenylmethacrylate, N-dimethylacrylamide, N-vinylcaprolactam, 4-acryloylmorpholine, vinyl ether and N-propyl vinyl ether;

the bifunctional-containing monomer compound (B), i.e., (B2), is one or more of hexanediol diacrylate, ethylene glycol dimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, ethylene glycol ethoxylated bisphenol A dimethacrylate, propoxylated neopentyl glycol diacrylate, cyclohexane dimethanol diacrylate, tricyclodecane dimethanol diacrylate and diethylene glycol divinyl ether;

the polyfunctional monomer compound (B), i.e., (B3), is one or more selected from trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

29. The UV-curable adhesive according to any one of claims 1 to 10, characterized in that: the photoinitiator (C) is a free radical photoinitiator with high activity at 200-400 nm; and/or

The auxiliary agent is one or more of a photo-thermal stabilizer, an adhesion promoter, a fluorescent indicator, a thixotropic agent, a pigment and an anti-mildew auxiliary agent.

30. The UV-curable adhesive according to claim 29, characterized in that: the photoinitiator (C) is one or more of benzoin and derivatives thereof, benzil ketal, phenylacetyl derivatives, benzophenone derivatives, acetophenone derivatives, diethoxyacetophenone or thioxanthone.

31. A method of making the UV curable adhesive of any one of claims 1-30 comprising the steps of:

(1) The tackifying resin is obtained by scheme 1 or scheme 2 below:

scheme 1

Step (1): polymerizing a carboxyl group-containing radical polymerizable monomer (I) and a comonomer (II) in a solvent under the action of a radical initiator, and controlling the molecular weight of the product by using a chain transfer agent, wherein the product is obtained from a radical polymer P1;

step (2): reacting the free radical polymer P1 in the step (1) with an unsaturated compound containing an epoxy group and having free radical polymerization, and evaporating the solvent to obtain a tackifying resin (D);

scheme 2

Step (1'): polymerizing a hydroxyl group-containing radical polymerizable monomer (III) and a comonomer (II) in a solvent under the action of a radical initiator, and controlling the molecular weight of the product by using a chain transfer agent, wherein the molecular weight is obtained from a radical polymer M1;

step (2'): reacting the free radical polymer M1 obtained in the step (1') with a compound which has free radical polymerization and contains isocyanate functional groups, converting carboxyl on a lateral group of a P1 molecular chain into a functional group with photocuring free radical polymerization, and evaporating a solvent to obtain tackifying resin (D);

(2) Putting the components (A), (B), (C), (D) and (E) into a mixing device such as a planetary stirring kettle, and stirring and mixing uniformly; and

optionally, (3) removing bubbles in vacuum and packaging, wherein the vacuum degree of vacuum defoaming is less than or equal to-0.085 MPa.