Active energy ray-curable resin composition, adhesive composition and adhesive

Abstract

To provide an active energy ray-curable resin composition which uses an urethane (meth)acrylate-based compound using a plant-derived raw material, and has good adhesion to various members, especially, good adhesive force when being formed into an adhesive.SOLUTION: An active energy ray-curable resin composition contains an urethane (meth)acrylate-based compound (A), wherein the urethane (meth)acrylate-based compound (A) is a reaction product of polyester polyol (a1) containing a dimer acid-derived structural site, polyvalent isocyanate (a2) and hydroxyl group-containing (meth)acrylate (a3), and has a number average molecular weight of 7,000 to 25,000.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an active energy ray curable resin composition, and more particularly to an active energy ray curable resin composition containing a urethane (meth) acrylate compound made from plant-derived raw materials, having good adhesion to various members, especially having good adhesive strength when used as an adhesive.

Background Art

[0002] Conventionally, urethane (meth) acrylate compounds obtained by reacting diol compounds such as polyester diol and polyether diol, diisocyanate compounds such as isophorone diisocyanate and diphenylmethane diisocyanate, and hydroxyl group-containing (meth) acrylate compounds such as hydroxyethyl acrylate are known as active energy ray curable resin compositions and are used in applications such as paints, coating agents, and adhesives.

[0003] However, many urethane (meth) acrylate compounds are composed of petroleum-derived raw materials, and the current situation is that they do not take into account environmental problems such as global warming. Also, while research on urethane (meth) acrylate compounds using plant-derived raw materials is actively underway, urethane (meth) acrylate compounds using polyester polyol made from dimer acid, which is a plant-derived raw material, have been proposed (for example, see Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the active energy ray-curable resin compositions containing urethane (meth)acrylate compounds in Patent Documents 1 to 3 above, the adhesiveness of the resulting adhesives is poor, and further improvement is required from the viewpoint of achieving both environmental compatibility and adhesive physical properties.

[0006] Therefore, under such circumstances, the present invention uses a urethane (meth)acrylate compound made from plant-derived raw materials, and provides an active energy ray-curable resin composition having good adhesiveness to various members, particularly good adhesiveness when used as an adhesive, and further provides an adhesive composition using the same and an adhesive.

Means for Solving the Problems

[0007] However, as a result of intensive studies to solve the above problems, the present inventors have found that in an active energy ray-curable resin composition containing a urethane (meth)acrylate compound, a polyester polyol (a1) containing a structural site derived from dimer acid, a polyvalent isocyanate (a2), and a hydroxyl group-containing (meth)acrylate (a3) are used. By using a urethane (meth)acrylate compound having a large number average molecular weight as the reaction product, it is suitable for environmental compatibility and has good adhesiveness to various members, particularly good adhesiveness when used as an adhesive, and thus completed the present invention.

[0008] That is, the gist of the present invention is an active energy ray-curable resin composition containing a urethane (meth)acrylate compound (A), wherein the urethane (meth)acrylate compound (A) is a reaction product of a polyester polyol (a1) containing a structural site derived from dimer acid, a polyvalent isocyanate (a2), and a hydroxyl group-containing (meth)acrylate (a3), and relates to an active energy ray-curable resin composition having a number average molecular weight of 7,000 to 25,000.

[0009] Furthermore, the present invention relates to an adhesive composition comprising the active energy ray-curable resin composition, and an adhesive obtained by curing such an adhesive composition.

[0010] In the present invention, a urethane (meth) acrylate compound (A) having a large molecular weight is prepared as the active energy ray-curable resin composition. However, in a urethane (meth) acrylate compound using commonly used plant-derived raw materials such as dimer acid and dimer diol, since it is plant-derived, it may contain impurities. When trying to obtain a urethane (meth) acrylate compound with a large molecular weight, there are concerns that it may gel or the adhesive physical properties may be adversely affected by impurities, and it is usually difficult to select. Surprisingly, it has been found that while maintaining environmental compatibility, the molecular weight can be improved and an improvement in adhesive strength can also be obtained.

Advantages of the Invention

[0011] The active energy ray-curable resin composition of the present invention is a reaction product of a polyester polyol (a1) containing a structural site derived from dimer acid, a polyvalent isocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3), using a plant-derived dimer acid, and is an active energy ray-curable resin composition containing a urethane (meth) acrylate compound having a number average molecular weight in a predetermined range. Therefore, while being suitable for environmental response, it has good adhesion to various members, especially good adhesive strength when used as an adhesive, and is an active energy ray-curable resin composition applicable to various uses such as coating agents, paints, inks, adhesives, etc. In particular, the active energy ray-curable resin composition of the present invention is useful as an adhesive because it has good adhesive strength.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments for carrying out the present invention will be specifically described, but the present invention is not limited thereto.

[0013] In the present invention, "(meth)acrylic" means acrylic or methacrylic, and "(meth)acrylate" means acrylate or methacrylate, respectively.

[0014] The active energy ray-curable resin composition of the present invention contains a urethane (meth)acrylate compound (A), and preferably further contains an ethylenically unsaturated monomer (B). Hereinafter, each component will be described.

[0015] <Urethane (meth)acrylate compound (A)> The urethane (meth)acrylate compound (A) in the present invention is a reaction product of a polyester polyol (a1) containing a structural site derived from dimer acid, a polyvalent isocyanate (a2), and a hydroxyl group-containing (meth)acrylate (a3).

[0016] Examples of the polyester polyol (a1) containing a structural site derived from dimer acid include those obtained by (1) a polycondensation reaction of dimer acid and a polyhydric alcohol, and those obtained by (2) a polycondensation reaction of a dimer diol obtained by reducing dimer acid and a polyvalent carboxylic acid. Among them, (1) is mentioned in terms of easy availability.

[0017] Examples of the dimer acid include thermally dimerized products of unsaturated fatty acids and hydrogenated dimer acids obtained by hydrogenating them. Specifically, it is a dimer mainly composed of unsaturated fatty acids having 10 to 24 carbon atoms, preferably around 18 carbon atoms, and is a dicarboxylic acid derived from unsaturated fatty acids such as oleic acids, linoleic acids, linolenic acids, and erucic acids. Main dimer acids include those having 36 and 44 carbon atoms.

[0018] As the polyhydric alcohol that undergoes a polycondensation reaction with dimer acid, for example, aliphatic or alicyclic polyhydric alcohols having 2 to 40 carbon atoms, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-eicosanediol and other linear polyhydric alcohols having 2 to 20 carbon atoms; 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 2-ethyl-1,6-hexanediol, 2,4-diethyl-1,5-pentanediol, neopentyl glycol, 2-ethyl-2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, dimer diol and other polyhydric alcohols having a branched chain of 4 to 40 carbon atoms; 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and other polyhydric alcohols having a cyclic structure in the molecule of 4 to 20 carbon atoms; diethylene glycol, triethylene glycol, polytetramethylene ether glycol, dimer diol and the like can be mentioned. These polyhydric alcohols may be used alone or in combination of two or more. Among them, in terms of availability and adhesive strength when used as an adhesive, linear polyhydric alcohols having 2 to 10 carbon atoms, particularly 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and polyhydric alcohols having a branched chain of 4 to 10 carbon atoms, particularly neopentyl glycol, are preferably used.

[0019] That is, the polyester polyol (a1) containing a structural site derived from the dimer acid is particularly preferably a polycondensate of the dimer acid and at least one glycol selected from 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol.

[0020] In addition, examples of the polycarboxylic acid that undergoes a polycondensation reaction with dimer diol include aliphatic dicarboxylic acids such as malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; alicyclic dicarboxylic acids such as 1,4 - cyclohexanedicarboxylic acid; and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6 - naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid, trimellitic acid, and furandicarboxylic acid. Among them, succinic acid, adipic acid, and sebacic acid are preferably used in terms of ease of availability and adhesive strength when used as an adhesive.

[0021] In the present invention, the term "carboxylic acid" includes derivatives of carboxylic acids such as carboxylates, carboxylic anhydrides, carboxylic halides, and carboxylic esters in addition to carboxylic acids.

[0022] In the present invention, the number average molecular weight of the polyester polyol (a1) containing a structural site derived from dimer acid is preferably 800 to 5000, particularly preferably 1000 to 4000, and even more preferably 2000 to 3000, in terms of handleability and adhesive strength when used as an adhesive. If such a number average molecular weight is too small, the adhesive strength tends to be low when used as an adhesive, and if it is too large, the viscosity of the polyester polyol (a1) becomes high, and the handleability and reactivity tend to decrease.

[0023] The above number average molecular weight can be determined from the hydroxyl value. The hydroxyl value can be measured by a method using an acetylation reagent or a phthalation reagent in accordance with JIS K1557 - 1(2007).

[0024] Examples of the polyvalent isocyanate (a2) used in the present invention include aliphatic polyvalent isocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, and lysine triisocyanate; alicyclic polyvalent isocyanates such as hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, and norbornene diisocyanate; aromatic polyvalent isocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate; and polyvalent isocyanates such as trimer compounds and multimer compounds of the above polyvalent isocyanates. Further, allophanate-type polyisocyanates, burette-type polyisocyanates, etc. are also included. These can be used alone or in combination of two or more.

[0025] Among these, aliphatic polyvalent isocyanates and alicyclic polyvalent isocyanates are preferred in terms of the adhesive physical properties when used as an adhesive. Further, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and hexamethylene diisocyanate are preferred, and isophorone diisocyanate is particularly preferred.

[0026] Examples of the hydroxyl group-containing (meth)acrylate (a3) used in the present invention include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate; 2-hydroxyethyl acryloyl phosphate; 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate; caprolactone-modified 2-hydroxyethyl (meth)acrylate; dipropylene glycol (meth)acrylate; fatty acid-modified glycidyl (meth)acrylate; polyethylene glycol mono (meth)acrylate; polypropylene glycol mono (meth)acrylate; and hydroxyl group-containing (meth)acrylates containing one ethylenically unsaturated group such as 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate; hydroxyl group-containing (meth)acrylates containing two ethylenically unsaturated groups such as glycerin di (meth)acrylate and 2-hydroxy-3-acryloyl-oxypropyl methacrylate; and hydroxyl group-containing (meth)acrylates containing three or more ethylenically unsaturated groups such as pentaerythritol tri (meth)acrylate, caprolactone-modified pentaerythritol tri (meth)acrylate, ethylene oxide-modified pentaerythritol tri (meth)acrylate, dipentaerythritol penta (meth)acrylate, caprolactone-modified dipentaerythritol penta (meth)acrylate, and ethylene oxide-modified dipentaerythritol penta (meth)acrylate. These can be used alone or in combination of two or more.

[0027] Among these, hydroxyl group-containing (meth)acrylates containing one ethylenically unsaturated group are particularly preferred in terms of the adhesive physical properties when used as an adhesive. Further, hydroxyalkyl (meth)acrylates are preferably used, and in particular, hydroxyalkyl (meth)acrylates having 1 to 4 carbon atoms in the alkyl group, especially 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate, are preferred.

[0028] The urethane (meth)acrylate compound (A) in the present invention is obtained by reacting the above components (a1) to (a3). The production method may be carried out according to a known method. Specifically, it can be produced as follows.

[0029] For example, (i) a method of charging the above polyester polyol (a1), polyvalent isocyanate (a2), and hydroxyl group-containing (meth)acrylate (a3) into a reactor all at once or separately and reacting them, (ii) a method of reacting a terminal isocyanate group-containing reaction product obtained by previously reacting polyester polyol (a1) and polyvalent isocyanate (a2) with hydroxyl group-containing (meth)acrylate (a3), (iii) a method of reacting polyester polyol (a1) with a reaction product obtained by previously reacting polyvalent isocyanate (a2) and hydroxyl group-containing (meth)acrylate (a3), etc. can be mentioned. From the viewpoints of reaction stability and reduction of by-products, etc., the method (ii) is preferable.

[0030] Regarding the method (ii) above, the reaction between polyester polyol (a1) and polyvalent isocyanate (a2) can be carried out using known reaction means. At that time, for example, by making the molar ratio of the isocyanate group in the polyvalent isocyanate compound (a2) to the hydroxyl group in the polyester polyol (a1) usually about 2n:(2n - 2) (n is an integer of 2 or more), isocyanate groups are left to enable an addition reaction with the hydroxyl group-containing (meth)acrylate (a3).

[0031] In the above molar ratio, n is 4 or more and 10 or less. The lower limit is preferably 5, more preferably 6. The upper limit is preferably 9, more preferably 8, and even more preferably 7. If the above molar ratio is too small, the adhesive strength tends to be low when used as an adhesive. If it is too large, the viscosity of the active energy ray-curable resin composition tends to be high and the handleability deteriorates.

[0032] The reaction molar ratio of the terminal isocyanate group-containing reaction product and the hydroxyl group-containing (meth)acrylate (a3) is, for example, when the isocyanate group of the terminal isocyanate group-containing reaction product has 2 and the hydroxyl group of the hydroxyl group-containing (meth)acrylate (a3) has 1, usually, the terminal isocyanate group-containing reaction product: the hydroxyl group-containing (meth)acrylate compound (a3) is about 1:2, and when the isocyanate group of the terminal isocyanate group-containing reaction product has 3 and the hydroxyl group of the hydroxyl group-containing (meth)acrylate (a3) has 1, usually, the terminal isocyanate group-containing reaction product: the hydroxyl group-containing (meth)acrylate compound (a3) is about 1:3.

[0033] In this addition reaction of the terminal isocyanate group-containing reaction product and the hydroxyl group-containing (meth)acrylate (a3), the urethane (meth)acrylate compound (A) of the present invention can be obtained by terminating the reaction when the residual isocyanate group content rate of the reaction system usually becomes 0.3% by weight or less.

[0034] In the present invention, in the reaction of the polyester polyol (a1) and the polyvalent isocyanate (a2), and further in the reaction of the terminal isocyanate group-containing reaction product and the hydroxyl group-containing (meth)acrylate (a3), it is also preferable to use a catalyst for the purpose of accelerating the reaction.

[0035] Examples of such catalysts include organometallic compounds such as dibutyltin dilaurate, trimethyltin hydroxide, tetra-n-butyltin; metal salts such as zinc octylate, tin octylate, cobalt naphthenate, stannous chloride, stannic chloride; amine-based catalysts such as triethylamine, benzyldiethylamine, 1,4-diazabicyclo[2,2,2]octane, 1,8-diazabicyclo[5,4,0]undecene, N,N,N’,N’-tetramethyl-1,3-butanediamine, N-ethylmorpholine; bismuth-based catalysts such as bismuth nitrate, bismuth bromide, bismuth iodide, bismuth sulfide, dibutylbismuth dilaurate, dioctylbismuth dilaurate and other organobismuth compounds, bismuth 2-ethylhexanoate salt, bismuth naphthenate salt, bismuth isodecanoate salt, bismuth neodecanoate salt, bismuth laurate salt, bismuth maleate salt, bismuth stearate salt, bismuth oleate salt, bismuth linoleate salt, bismuth acetate salt, bismuth trisneodecanoate, bismuth disalicylate salt and other organic acid bismuth salts. Among these, dibutyltin dilaurate and 1,8-diazabicyclo[5,4,0]undecene are preferred.

[0036] In addition, in the reaction of polyester polyol (a1) and polyvalent isocyanate (a2), and further in the reaction of the resulting terminal isocyanate group-containing reaction product with a hydroxyl group-containing (meth)acrylate (a3), an organic solvent having no functional group reactive with the isocyanate group, for example, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatics such as toluene and xylene can be used.

[0037] The reaction temperature is generally 30 to 90°C, preferably 40 to 80°C, and the reaction time is generally 2 to 12 hours, preferably 3 to 10 hours.

[0038] Thus, the urethane (meth)acrylate-based compound (A) is obtained.

[0039] In the present invention, it is important that the number average molecular weight of the urethane (meth) acrylate compound (A) obtained above is from 7,000 to 25,000, particularly preferably from 10,000 to 23,000, more preferably from 12,000 to 22,000, and especially preferably from 15,000 to 20,000. If such a number average molecular weight is too small, the adhesive strength when used as an adhesive will be low. If it is too large, the viscosity of the resin composition will be high, resulting in poor handleability, or there will be problems such as gelation due to impurities contained in the dimer acid derived from plants.

[0040] The weight average molecular weight of the urethane (meth) acrylate compound (A) is preferably from 15,000 to 100,000, particularly preferably from 20,000 to 90,000, and more preferably from 30,000 to 80,000. If such a weight average molecular weight is too small, the adhesive strength when used as an adhesive tends to be low. If it is too large, the viscosity of the resin composition will be high, resulting in a decrease in handleability, or there will be a tendency for problems such as gelation due to impurities contained in the dimer acid derived from plants to occur.

[0041] The above-mentioned number average molecular weight and weight average molecular weight are the number average molecular weight and weight average molecular weight in terms of standard polystyrene molecular weight, and are measured by using four columns in series: ACQUITY APC XT 450×1, ACQUITY APC XT 200×1, and ACQUITY APC XT 45×2 on a high performance liquid chromatograph (manufactured by Waters, "ACQUITY APC system"). In that case, when the ethylenically unsaturated monomer (B) described below is contained in the measurement object, the number average molecular weight and weight average molecular weight are determined after removing the ethylenically unsaturated monomer (B).

[0042] <Ethylenically unsaturated monomer (B)> The ethylenically unsaturated monomer (B) used in the present invention may be an ethylenically unsaturated monomer having one or more ethylenically unsaturated groups in one molecule, and examples thereof include monofunctional monomers, bifunctional monomers, and monomers having three or more functional groups.

[0043] The monofunctional monomer may be any monomer containing one ethylenically unsaturated group. For example, styrene, vinyltoluene, chlorostyrene, α-methylstyrene, methyl (meth)acrylate, ethyl (meth)acrylate, acrylonitrile, vinyl acetate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-phenoxy-2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, glycerin mono(meth)acrylate, glycidyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, n-stearyl (meth)acrylate, benzyl (meth)acrylate, phenol ethylene oxide modified (meth)acrylate, nonylphenol propylene oxide modified (meth)acrylate, half ester (meth)acrylate of phthalic acid derivatives such as 2-(meth)acryloyloxy-2-hydroxypropyl phthalate, tetrahydrofurfuryl (meth)acrylate, carbitol (meth)acrylate, benzyl (meth)acrylate, caprolactone modified 2-hydroxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, allyl (meth)acrylate, acryloylmorpholine, 2-hydroxyethyl acrylamide, N-methylol (meth)acrylamide, N-vinylpyrrolidone, 2-vinylpyridine, 2-(meth)acryloyloxyethyl acid phosphate monoester, etc. can be mentioned.

[0044] In addition to the above-mentioned monofunctional monomers, Michael adducts of acrylic acid or mono-esters of 2-acryloyloxyethyl dicarboxylic acid are also included. Examples of the Michael adducts of acrylic acid include acrylic acid dimer, methacrylic acid dimer, acrylic acid trimer, methacrylic acid trimer, acrylic acid tetramer, methacrylic acid tetramer, and the like. Examples of the mono-ester of 2-acryloyloxyethyl dicarboxylic acid, which is a carboxylic acid having a specific substituent, include 2-acryloyloxyethyl succinic acid mono-ester, 2-methacryloyloxyethyl succinic acid mono-ester, 2-acryloyloxyethyl phthalic acid mono-ester, 2-methacryloyloxyethyl phthalic acid mono-ester, 2-acryloyloxyethyl hexahydrophthalic acid mono-ester, 2-methacryloyloxyethyl hexahydrophthalic acid mono-ester, and the like. Furthermore, oligoester acrylate is also included.

[0045] The bifunctional monomer may be any monomer containing two ethylenically unsaturated groups. For example, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide-modified bisphenol A type di(meth)acrylate, propylene oxide-modified bisphenol A type di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,6-hexanediol ethylene oxide-modified di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, phthalic acid diglycidyl ester di(meth)acrylate, hydroxypivalic acid-modified neopentyl glycol di(meth)acrylate, ethylene oxide-modified isocyanuric acid diacrylate, 2-(meth)acryloyloxyethyl acid phosphate diester, etc. can be mentioned.

[0046] Examples of monomers having three or more functional groups include monomers containing three or more ethylenically unsaturated groups, such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tri(meth)acryloyloxyethoxytrimethylolpropane, glycerin polyglycidyl ether poly(meth)acrylate, ethylene oxide-modified isocyanuric acid triacrylate, ethylene oxide-modified dipentaerythritol penta(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified pentaerythritol tri(meth)acrylate, ethylene oxide-modified pentaerythritol tetra(meth)acrylate, caprolactone-modified dipentaerythritol penta(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, caprolactone-modified pentaerythritol tri(meth)acrylate, caprolactone-modified pentaerythritol tetra(meth)acrylate, succinic acid-modified pentaerythritol tri(meth)acrylate, and the like.

[0047] Alternatively, as the ethylenically unsaturated monomer (B), a urethane (meth)acrylate compound obtained by reacting a polyisocyanate compound and a (meth)acrylate compound containing one hydroxyl group, or a urethane (meth)acrylate compound obtained by reacting a polyisocyanate compound, a (meth)acrylate compound containing one hydroxyl group, and a polyol compound (excluding the urethane (meth)acrylate compound (A)) may be used.

[0048] These ethylenically unsaturated monomers (B) may be used alone or in combination of two or more. Further, the ethylenically unsaturated monomer (B) may be separately blended with the urethane (meth) acrylate compound (A), or may be present in part or in whole in the system during the production as a production raw material of the urethane (meth) acrylate compound (A). Furthermore, it may be contained as a reaction solvent in the reactions (a1) to (a3).

[0049] In the present invention, the content of the ethylenically unsaturated monomer (B) is preferably 20 to 150 parts by weight, particularly preferably 30 to 100 parts by weight, and still more preferably 40 to 80 parts by weight, based on 100 parts by weight of the urethane (meth) acrylate compound (A), in terms of the adhesive strength when used as an adhesive. If the content of the ethylenically unsaturated monomer (B) is too small or too large, it tends to be difficult to obtain sufficient adhesive strength when used as an adhesive.

[0050] <Photoinitiator (C)> In the present invention, it is preferable to further contain a photoinitiator (C) in order to more efficiently perform curing by active energy rays.

[0051] As the photopolymerization initiator (C), for example, acetophenones such as diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal, 4-(2-hydroxyethoxy)-phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenylketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, phenylglyoxylic acid methyl ester; benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; benzophenones such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzenemethanaminium bromide, (4-benzoylbenzyl)trimethylammonium chloride; thioxanthones such as 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one mesochloride;Acylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; etc. may be mentioned. In addition, only one kind of these photoinitiators (C) may be used alone, or two or more kinds may be used in combination.;

[0052] Also, as these auxiliaries, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Michler's ketone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethyl benzoate, ethyl 4-dimethylaminobenzoate, (n-butoxy)ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, etc. can also be used in combination.

[0053] Among these, it is preferable to use benzyldimethylketal, 1-hydroxycyclohexyl phenyl ketone, benzoin isopropyl ether, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one.

[0054] The content of the photoinitiator (C) is preferably 0.1 to 40 parts by weight, more preferably 0.5 to 20 parts by weight, and still more preferably 1 to 10 parts by weight with respect to 100 parts by weight in total of the urethane (meth)acrylate-based compound (A) and the ethylenically unsaturated monomer (B). If the content of the photoinitiator (C) is too small, there is a tendency for poor curing, and if it is too large, the solution stability tends to decrease, such as precipitation when coated, or problems such as embrittlement and coloring tend to occur easily.

[0055] In the production of the active energy ray-curable composition obtained in the present invention, the method of mixing the urethane (meth) acrylate-based compound (A), ethylenically unsaturated monomer (B), and photopolymerization initiator (C) is not particularly limited, and they can be mixed by various methods. For example, they can be appropriately selected such as mixing all the components at once, or mixing any components first and then mixing the remaining components.

[0056] Thus, the active energy ray-curable resin composition of the present invention is obtained. Further, if necessary, a surface conditioner, a leveling agent, a polymerization inhibitor, etc. can be further blended.

[0057] The surface conditioner is not particularly limited, and examples thereof include alkyd resins. Such an alkyd resin has an action of imparting film-forming properties during coating and an action of improving adhesiveness to the surface of a metal thin film.

[0058] As the leveling agent, any known general leveling agent can be used as long as it has an action of imparting wettability to the base material of the coating solution and an action of reducing the surface tension. For example, silicone-modified resins, fluorine-modified resins, alkyl-modified resins, etc. can be used. These can be used alone or in combination of two or more.

[0059] Examples of the polymerization inhibitor include p-benzoquinone, naphthoquinone, toluquinone, 2,5-diphenyl-p-benzoquinone, hydroquinone, 2,5-di-t-butylhydroquinone, methylhydroquinone, methoxyphenol, 2,6-di-t-butyl-p-cresol, mono-t-butylhydroquinone, p-t-butylcatechol, etc. Among them, methoxyphenol and 2,6-di-t-butyl-p-cresol are preferable. These can be used alone or in combination of two or more.

[0060] The active energy ray-curable resin composition of the present invention is cured by irradiating active energy rays after being applied and dried on various base materials.

[0061] As a coating method for the above active energy ray-curable resin composition, it is not particularly limited. For example, wet coating methods such as spray, shower, dipping, roll, spin, curtain, flow, slit, die, gravure, comma, dispenser, screen printing, inkjet printing, etc. can be mentioned.

[0062] When applying the above coating, if necessary, an organic solvent can be blended to adjust the viscosity. Examples of such organic solvents include alcohols such as methanol, ethanol, propanol, n-butanol, and i-butanol; ketones such as acetone, methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone; cellosolves such as ethyl cellosolve; aromatics such as toluene and xylene; glycol ethers such as propylene glycol monomethyl ether; acetate esters such as methyl acetate, ethyl acetate, and butyl acetate; and diacetone alcohol. These above organic solvents may be used alone or in combination of two or more.

[0063] Also, when the above active energy ray-curable resin composition is a solid or a high-viscosity liquid, a hot melt method in which the active energy ray-curable resin composition is heated to reduce the viscosity and then coated by the above method can also be mentioned.

[0064] As such active energy rays, for example, rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, electromagnetic waves such as X-rays and γ-rays, and in addition, electron beams, proton beams, neutron beams, etc. can be used. However, curing by ultraviolet irradiation is advantageous in terms of curing speed, availability of irradiation devices, price, etc. Note that when electron beam irradiation is performed, it can be cured without using the photopolymerization initiator (C).

[0065] As a method of curing by ultraviolet irradiation, using a high-pressure mercury lamp, ultra-high-pressure mercury lamp, carbon arc lamp, metal halide lamp, xenon lamp, chemical lamp, electrodeless discharge lamp, LED, etc. that emit light in the wavelength range of 150 to 450 nm, 30 to 3,000 mJ / cm2 It suffices to irradiate to such an extent. After ultraviolet irradiation, heating can be carried out as necessary to achieve complete curing.

[0066] Regarding the film thickness of the cured coating film, in view of light transmission for the photopolymerization initiator (C) to react uniformly, it is usually 1 to 300 μm, preferably 2 to 250 μm, more preferably 5 to 200 μm.

[0067] In the present invention, the glass transition temperature (Tg) of the cured product of the active energy ray curable resin composition is preferably -30°C or higher, more preferably -30 to 50°C, still more preferably -20 to 45°C, particularly preferably -10 to 40°C, and especially preferably 0 to 30°C. When such a glass transition temperature (Tg) is out of the above range, the adhesive strength tends to decrease when used as an adhesive.

[0068] The method for measuring the above glass transition temperature (Tg) is as follows. That is, the active energy ray curable resin composition is applied to an easily adhesive treated polyethylene terephthalate (PET) film (thickness 125 μm) so that the film thickness after curing becomes 100 μm using an applicator, and irradiated with ultraviolet rays under the conditions of 80 W / cm (high pressure mercury lamp) × 18 cmH × 1.9 m / min × 3 Pass (integrated irradiation dose 2,400 mJ / cm 2 ), cured, and a test piece having a length of 20 mm × a width of 3 mm is cut out from the adhesive sheet for measuring adhesive strength thus produced. Using such a test piece, measurement is carried out in the tensile mode of a dynamic viscoelasticity measuring device "DVA-225" manufactured by IT Measurement & Control Co., Ltd. at a frequency of 1 Hz, a temperature rising rate of 3°C / min, and a strain of 0.1%. The ratio (tanδ) of the imaginary part (loss elastic modulus) to the real part (storage elastic modulus) of the obtained complex elastic modulus is determined, and the maximum peak temperature of this tanδ is taken as the glass transition temperature (°C).

[0069] Regarding the gel fraction after curing of the above-mentioned active energy ray-curable resin composition, it is preferably 10% by weight or more, more preferably 20 to 95% by weight, still more preferably 30 to 90% by weight, and particularly preferably 40 to 85% by weight from the viewpoints of durability and adhesion. If the gel fraction is too low, the durability tends to decrease due to a decrease in cohesive force. In addition, if the gel fraction is too high, there is a concern that the adhesion may decrease due to an increase in cohesive force.

[0070] The above gel fraction serves as an index of the degree of crosslinking and is calculated, for example, by the following method. That is, a cured coating film sheet (one without a separator) in which a cured coating film is formed on a polymer sheet serving as a base material (for example, a PET film, etc.) is wrapped with a 200-mesh SUS wire mesh and immersed in toluene at 23 °C for 24 hours. The weight percentage of the insoluble cured coating film component remaining in the wire mesh after immersion with respect to the weight of the cured coating film component before immersion is defined as the gel fraction. However, the weight of the base material is subtracted.

[0071] The active energy ray-curable resin composition of the present invention uses a plant-derived dimer acid and is an active energy ray-curable resin composition with reduced environmental load. The biomass ratio can be represented by the ratio of the number of carbon atoms derived from plants among all the carbon atoms contained in the active energy ray-curable resin composition, and is preferably 30C% (C% represents the ratio of carbon) or more, more preferably 40C% or more, still more preferably 50C% or more, particularly preferably 60C% or more, and especially preferably 70C% or more. The biomass ratio can be calculated by calculating the ratio of the number of carbon atoms of the raw materials derived from plants from the number of carbon atoms of all the raw materials constituting the active energy ray-curable resin composition, including polyester polyol (a1) containing a structural site derived from dimer acid, polyisocyanate (a2), hydroxyl group-containing (meth)acrylate (a3), and ethylenically unsaturated monomer (B). More precisely, it can be measured by the method specified in ASTM D6866.

[0072] As the substrate to be coated with the active energy ray-curable resin composition obtained in the present invention, there may be mentioned polyolefin resins, polyester resins, polycarbonate resins, acrylonitrile-butadiene-styrene copolymers (ABS), polystyrene resins, polyamide resins, etc., and molded articles thereof (films, sheets, cups, etc.), metal substrates (metal vapor deposition layers, metal plates (copper, stainless steel (SUS304, SUSBA, etc.), aluminum, zinc, magnesium, etc.)), glass, etc., and composite substrates thereof.

[0073] In the present invention, the active energy ray-curable resin composition containing the urethane (meth) acrylate compound (A) has good adhesion to various members, especially good adhesive strength when used as an adhesive, and is an active energy ray-curable resin composition applicable to various uses such as coating agents, paints, inks, adhesives, etc. In particular, it is very useful as an adhesive because it has good adhesive strength.

Examples

[0074] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, "parts" and "%" mean weight basis. In addition, the number average molecular weight, weight average molecular weight, viscosity, and gel fraction of the urethane (meth) acrylate compound were measured according to the aforementioned methods, and the biomass ratio was calculated by the aforementioned methods.

[0075] The following were prepared as the polyester polyol (a1) containing a structural site derived from dimer acid. · "Priplast1838": manufactured by CRODA, dimer acid-based polyester polyol (hydroxyl value 60.0 mgKOH / g, number average molecular weight 1870) · "Priplast3196": manufactured by CRODA, dimer acid-based polyester polyol (hydroxyl value 37.0 mgKOH / g, number average molecular weight 3032) · "Priplast 3199": manufactured by Croda, dimer acid-based polyester polyol (hydroxyl value 56.0 mgKOH / g, number average molecular weight 2004)

[0076] <Example 1> [Preparation of urethane acrylate (A-1)] Into a flask equipped with an internal thermometer, stirrer, and condenser, 43.7 parts of isophorone diisocyanate (IPDI) as a polyvalent isocyanate, 306.6 parts of "Priplast 1838" as a polyester polyol, 90 parts of butyl acrylate (BA) as an ethylenically unsaturated monomer (B-1), 0.02 part of 2,6-di-t-butyl-p-cresol as a polymerization inhibitor, and 0.06 part of dibutyltin dilaurate as a reaction catalyst were added, and the reaction was carried out at 80°C. When the residual isocyanate groups reached 0.6% or less, the mixture was cooled to 70°C, 9.7 parts of 4-hydroxybutyl acrylate (4HBA) as a hydroxyl group-containing (meth)acrylate and 0.18 part of 4-methoxyphenol as a polymerization inhibitor were added, and the reaction was carried out at 70°C. The reaction was terminated when the residual isocyanate groups reached 0.1% or less, and a composition containing urethane acrylate (A-1) was obtained.

[0077] [Preparation of active energy ray curable resin composition] To a total of 100 parts of the above urethane acrylate (A-1) and ethylenically unsaturated monomer (B-1), 35 parts of isobornyl acrylate (IBOA) as an ethylenically unsaturated monomer (B-2) and 4 parts of 1-hydroxy-cyclohexyl-phenyl-ketone as a photopolymerization initiator (C) were uniformly mixed to obtain an active energy ray curable resin composition. The obtained active energy ray curable resin composition was evaluated for tackiness as follows.

[0078] [Tackiness] (Preparation of pressure-sensitive adhesive sheet for measuring adhesive strength) The obtained active energy ray-curable resin composition was applied to an easily adherable polyethylene terephthalate (PET) film (thickness 125 μm) so that the film thickness after curing would be 100 μm using an applicator, and irradiated with ultraviolet rays under the conditions of 80 W / cm (high-pressure mercury lamp) × 18 cmH × 1.9 m / min × 3 Pass (integrated irradiation dose 2,400 mJ / cm 2 ) using a desktop UV irradiation device (manufactured by Eye Graphics Co., Ltd., "Conveyor-type Desktop Irradiation Device") to cure it, thereby obtaining an adhesive sheet for measuring adhesive strength.

[0079] (Test method) After cutting the obtained adhesive sheet for measuring adhesive strength into pieces of 25 mm × 100 mm, it was pressure-bonded to a stainless steel plate (SUS304BA plate) as the adherend by reciprocating 2 times using a 2 kg rubber roller in an atmosphere of 23°C and a relative humidity of 50% to prepare a test piece. After leaving this test piece to stand in the same atmosphere for 30 minutes, a 180-degree peel test was conducted at a peel rate of 0.3 m / min to measure the adhesive strength (N / 25 mm). The measurement results are shown in Table 1.

[0080] <Examples 2 to 6, Comparative Examples 1 to 2> In Example 1, the polyester polyol (a1), polyvalent isocyanate (a2), hydroxyl group-containing (meth)acrylate (a3), ethylenically unsaturated monomer (B-1), ethylenically unsaturated monomer (B-2), and the type and charged amount of the reaction catalyst were changed as described in Tables 1 and 2, and the same procedure was carried out to obtain an active energy ray-curable resin composition. The obtained active energy ray-curable resin composition was evaluated for adhesiveness in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0081]

Table 1

[0082]

Table 2

[0083] The abbreviations in Tables 1 and 2 are as follows. IPDI: Isophorone diisocyanate 4HBA: 4-Hydroxybutyl acrylate HEA: 2-Hydroxyethyl acrylate BA: Butyl acrylate IBOA: Isobornyl acrylate IDAA: Isodecyl acrylate DBTL: Dibutyltin dilaurate

[0084] From the results of Tables 1 and 2 above, the active energy ray-curable resin compositions of Examples 1 to 6 are urethane acrylates obtained using a polyester polyol having a structural site derived from a dimer, which are suitable for environmental response and have good adhesiveness when used as an adhesive. On the other hand, in the active energy ray-curable resin compositions of Comparative Examples 1 and 2, the number average molecular weight of the urethane acrylate was too small, so the adhesiveness as an adhesive was poor.

Industrial Applicability

[0085] The active energy ray-curable resin composition of the present invention is suitable for environmental response and has good adhesiveness to various members, especially when used as an adhesive, and is an active energy ray-curable resin composition applicable to various uses such as coating agents, paints, inks, adhesives, etc. In particular, the active energy ray-curable resin composition of the present invention is useful as an adhesive because it has good adhesiveness.

Claims

1. An active energy ray-curable resin composition containing a urethane (meth) acrylate compound (A), wherein the urethane (meth) acrylate compound (A) is a reaction product of a polyester polyol (a1) containing a structural site derived from dimer acid, a polyvalent isocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3), and has a number average molecular weight of 7,000 to 25,000, The active energy ray-curable resin composition is characterized in that the gel fraction when the active energy ray-curable resin composition is cured is 40 to 85% by mass.

2. The active energy ray-curable resin composition according to claim 1, wherein the polyvalent isocyanate (a2) is at least one of an aliphatic polyvalent isocyanate and an alicyclic polyvalent isocyanate.

3. The active energy ray-curable resin composition according to claim 1 or 2, wherein the polyester polyol (a1) containing a structural site derived from dimer acid is a polycondensate of dimer acid and at least one glycol selected from 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol.

4. The active energy ray-curable resin composition according to any one of claims 1 to 3, further containing an ethylenically unsaturated monomer (B).

5. The active energy ray-curable resin composition according to any one of claims 1 to 4, further containing a photopolymerization initiator (C).

6. The active energy ray-curable resin composition according to any one of claims 1 to 5, wherein the glass transition temperature of the cured product of the active energy ray-curable resin composition is -30°C or higher.

7. An adhesive composition comprising the active energy ray-curable resin composition according to any one of claims 1 to 6.

8. An adhesive characterized in that the adhesive composition according to claim 7 is cured.

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