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

Abstract

The present invention provides an active energy ray-curable composition having excellent adhesive force, retention force, and thermal stability as an active energy ray-curable composition. An active energy ray-curable composition containing a polyester (A) having a structural unit derived from a polycarboxylic acid (alpha) and a structural unit derived from a polyol (beta), the polyester (A) being a polyester (A1) further having a structural unit derived from a compound (B) having a photoreactive group.

Description

Technical Field

[0001] This invention relates to an active energy ray curable composition, an adhesive for curing the active energy ray curable composition, and an adhesive sheet. More specifically, it relates to an active energy ray curable composition, an adhesive, and an adhesive sheet that are made from an active energy ray curable composition, which has excellent curability based on active energy rays without having unsaturated groups, and which has excellent heat resistance, adhesion, and holding power. Background Technology

[0002] Previously, polyester was widely used in films, plastic bottles, fibers, toners, motor parts, adhesives, and bonding agents due to its excellent heat resistance, chemical resistance, durability, and mechanical strength. Furthermore, polyester's high polarity due to its polymer structure gives it excellent adhesion to polar polymers such as polyester, polyvinyl chloride, polyimide, and epoxy resins, as well as to metals such as copper and aluminum.

[0003] Adhesives used in adhesive sheets such as adhesive labels and tapes have traditionally been solvent-based adhesives, made by dissolving adhesive polymers in solvents. In recent years, to reduce environmental impact and regulate VOCs (Volatile Organic Compounds) emissions, solvent-free adhesives that do not use organic solvents have gained attention. Solvent-free adhesives include water-based adhesives that are dispersed / dissolved in water, and UV-cured adhesives that are cured using active energy rays such as ultraviolet light. Water-based adhesives require more energy to evaporate water than solvent-based adhesives, and due to the emulsifiers in the main component, they have performance issues such as poorer water resistance compared to solvent-based adhesives. Furthermore, UV-cured adhesives require the embedding of unsaturated groups that react with active energy rays to become crosslinking points in the structure to improve the adhesive's cohesiveness, or the inclusion of compounds with unsaturated groups in the adhesive. However, during hot-melt coating, heating can cause reactions of the unsaturated groups, leading to increased viscosity or gelation, resulting in thermal stability problems. Therefore, solvent-free adhesives used in hot melt coating are required to have high thermal stability and adhesive properties equal to or better than those of solvent-based adhesives.

[0004] Patent Document 1 discloses a photocrosslinking polyester adhesive composition formed from a polyester having unsaturated groups, a photoinitiator, and a crosslinking agent.

[0005] In addition, Patent Document 2 discloses an adhesive for photocrosslinking optical components formed from polyester, a compound containing unsaturated groups, a polymerization initiator, and a crosslinking agent.

[0006] Furthermore, Patent Document 3 discloses a radiation-cured and re-peelable adhesive sheet formed from polyester, a radiation-cured resin having unsaturated groups, a radiation reaction initiator, and a crosslinking agent.

[0007] Furthermore, Patent Document 4 discloses a UV-curable composition formed from an epoxidized grease having UV-active sites and a polycarboxylic acid.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2009-102476

[0011] Patent Document 2: Japanese Patent Application Publication No. 2009-209279

[0012] Patent Document 3: Japanese Patent Application Publication No. 2010-59336

[0013] Patent Document 4: Japanese Patent Publication No. 2022-535379 Summary of the Invention

[0014] The problem the invention aims to solve

[0015] In recent years, in order to reduce environmental impact, there has been a search for environmentally friendly adhesives such as biomass adhesives using plant-derived raw materials and solvent-free adhesives that do not use organic solvents. Traditionally used thermosetting adhesives are made from petroleum-based raw materials and are diluted with organic solvents before use, thus generating VOCs that can cause environmental pollution, and releasing CO2 during combustion, leading to environmental impact.

[0016] Furthermore, for the active energy radiation-curing adhesives that have been used in the past, it is necessary to introduce unsaturated groups into the adhesive as active energy radiation curing components, or to formulate compounds containing unsaturated groups, and further, to include thermosetting crosslinking agents. Unsaturated groups and crosslinking agents react with heat, so in the application of solvent-free adhesives that involve high-temperature heating processes such as hot melt, there are problems with thermal stability such as viscosity increase, gelation, and thermal decomposition during the manufacturing process, making them difficult to use.

[0017] For example, Patent Document 1 discloses a technology for a polyester-based photocrosslinking adhesive composition, in which the polyester resin has unsaturated groups derived from (meth)acrylate as photocrosslinking components, thus presenting a problem with thermal stability.

[0018] In addition, Patent Document 2 discloses a technology for adhesives for optical and / or thermally crosslinked optical components. The adhesive composition uses compounds containing unsaturated groups and thermosetting crosslinking agents, which crosslink due to heat. This results in problems with thermal stability and room for improvement in terms of suitability for hot melt coating.

[0019] Patent document 3 discloses a technology for radiation-cured re-peelable adhesive sheets, which contain a large amount of radiation-cured resin with unsaturated groups, thus having problems with thermal stability and adhesion.

[0020] Patent document 4 discloses a technology for a UV-curable composition formed from an epoxidized grease with UV-active sites and a polycarboxylic acid. Although it does not contain unsaturated groups as an active energy ray curing component, it contains epoxy groups, which may react with carboxyl groups or undergo ring-opening polymerization of epoxy groups due to heat. Therefore, its thermal stability at high temperatures is problematic.

[0021] Against this background, the present invention provides active energy ray curable compositions, adhesives and adhesive sheets with excellent adhesion, holding power and thermal stability.

[0022] Solution for solving the problem

[0023] In view of the above situation, the inventors conducted in-depth research and found that an active energy ray curable composition containing polyester having structural units derived from polycarboxylic acids, structural units derived from polyols, and structural units derived from compounds having photoreactive groups, can obtain a composition with excellent active energy ray curability, and thus excellent thermal stability, adhesion, and holding power, without containing unsaturated groups that would cause a decrease in thermal stability.

[0024] Furthermore, the inventors conducted in-depth research in view of the aforementioned situation and discovered that an active energy ray-curable adhesive composition comprising a polyester having structural units derived from polycarboxylic acids and structural units derived from polyols, and a compound having photoreactive groups, can obtain an active energy ray-curable adhesive composition with excellent active energy ray curability, and thus excellent thermal stability, adhesion, and holding power, by not containing unsaturated groups that would cause a decrease in thermal stability.

[0025] That is, the present invention is based on the following [1] to

[16] .

[0026] [1] An active energy ray curable composition comprising a polyester (A) having structural units derived from polycarboxylic acids (α) and structural units derived from polyols (β),

[0027] The aforementioned polyester (A) further comprises polyester (A1) having structural units derived from a compound (B) having photoreactive groups.

[0028] [2] An active energy ray curable composition comprising a polyester (A) having structural units derived from polycarboxylic acids (α) and structural units derived from polyols (β), and a compound (B) having photoreactive groups.

[0029] The content of the compound (C) containing polymerizable unsaturated groups in the aforementioned active energy ray curable composition is less than 15 parts by mass relative to 100 parts by mass of polyester (A).

[0030] [3] The active energy ray curable composition according to [1] further comprises a polyester (A2) having structural units derived from polycarboxylic acids (α) and polyols (β) but not having structural units derived from compounds (B) having photoreactive groups.

[0031] [4] According to the active energy ray curable composition described in [1] or [3], wherein the aforementioned compound (B) having a photoreactive group is a compound (b1) having a hydrogen-abstracting photoreactive group and / or a compound (b2) having a cleavage-type photoreactive group.

[0032] [5] The active energy ray curable composition according to any one of [1], [3], [4], wherein the aforementioned structural unit derived from the compound (B) having a photoreactive group is formed by embedding an ester bond into the main chain of a polyester (A1).

[0033] [6] The active energy ray curable composition according to any one of [1], [3] to [5], wherein the aforementioned compound (B) having a photoreactive group is a polycarboxylic acid (α).

[0034] [7] According to the active energy ray curable composition described in [2], wherein the aforementioned compound (B) having a photoreactive group is a hydrogen-abstracting photopolymerization initiator.

[0035] [8] The active energy ray curable composition according to [2] or [7], wherein the aforementioned compound (B) having a photoreactive group does not have a carboxyl group or a hydroxyl group as a functional group.

[0036] [9] The active energy ray curable composition according to any one of [1] to [8], wherein the glass transition temperature of the aforementioned polyester (A) is -80 to 30°C.

[0037]

[10] The active energy ray curable composition according to any one of [1] to [9], wherein the weight average molecular weight of the aforementioned polyester (A) is 5,000 to 500,000.

[0038]

[11] The active energy ray curable composition according to any one of [1] to

[10] , wherein the concentration of unsaturated groups of the aforementioned polyester (A) is less than 1 mmol / g.

[0039]

[12] The active energy ray curable composition according to any one of [1] to

[11] has a melt viscosity change rate of 20 to 500% before and after heating at 200°C for 3 hours.

[0040]

[13] The active energy ray curable composition according to any one of [1] to

[12] , wherein the content of the organic solvent in the aforementioned active energy ray curable composition is less than 10% by mass.

[0041]

[14] An adhesive, which is the cured product of the active energy ray curable composition described in any one of [1] to

[13] .

[0042]

[15] The adhesive according to

[14] , wherein the gel fraction of the adhesive is 1 to 100%.

[0043]

[16] An adhesive sheet comprising the adhesive described in

[14] or

[15] .

[0044] The effects of the invention

[0045] The active energy ray curable composition of the present invention can form an adhesive with excellent active energy ray curability, adhesion, holding power and thermal stability, and is particularly effective as a solvent-free adhesive for use in adhesive tapes and adhesive labels.

[0046] Generally speaking, in order to improve the curability, adhesion, and holding power of active energy ray curing compositions, the compositions need to contain compounds with unsaturated groups as curing components based on active energy rays.

[0047] However, the presence of unsaturated groups can cause polymerization due to heat. Therefore, in the hot melt process of solvent-free adhesives that require melting the resin at high temperatures, the viscosity increases, gelation occurs, and there are problems with thermal stability, making them unusable.

[0048] In this invention, by using a polyester with photoreactive groups, without containing unsaturated groups that become crosslinking points due to active energy rays, the active energy ray curing property is excellent, and the thermal stability, adhesion and holding power are also excellent.

[0049] Furthermore, the present invention provides an active energy ray curable composition containing polyester and a compound with photoreactive groups. This composition exhibits excellent curability to active energy rays without the presence of unsaturated groups or crosslinking agents that are previously necessary as crosslinking points due to active energy rays. Consequently, it also demonstrates excellent thermal stability, adhesion, and holding power. Detailed Implementation

[0050] The following describes the structure of the present invention in detail, but these are examples illustrating preferred embodiments.

[0051] Furthermore, in this invention, the term "class" appended to the compound name is a concept that includes not only the compound itself but also its derivatives. For example, the term "carboxylic acid class" includes not only carboxylic acids but also carboxylic acid salts, carboxylic anhydrides, carboxyl halides, carboxylic acid esters, and other carboxylic acid derivatives.

[0052] In this invention, "structural unit derived from..." refers not only to the structural unit of the compound, but also to the structural unit chemically derived from the compound in a form other than the structural unit of the compound.

[0053] In addition, "X and / or Y (X and Y are arbitrary constructs)" refers to at least one of X and Y, and has three meanings: only X, only Y, and both X and Y.

[0054] An active energy ray curable composition (hereinafter referred to as "the Composition 1") according to one embodiment of the present invention comprises a polyester (A) having structural units derived from a polycarboxylic acid (α) and structural units derived from a polyol (β), wherein the polyester (A) is a polyester (A1) that also has structural units derived from a compound (B) having a photoreactive group.

[0055] In addition, another embodiment of the present invention provides an active energy ray curable composition (hereinafter referred to as "the Composition 2") comprising a polyester (A) having structural units derived from polycarboxylic acids (α) and structural units derived from polyols (β), and a compound (B) having photoreactive groups, wherein the content of the compound (C) containing polymerizable unsaturated groups contained in the aforementioned Composition 2 is less than 15 parts by mass relative to 100 parts by mass of polyester (A).

[0056] Hereinafter, Composition 1 and Composition 2 are sometimes collectively referred to as "the Composition".

[0057] First, let's explain regarding polyester (A).

[0058] <Polyester (A)>

[0059] As mentioned earlier, polyester (A) contains structural units derived from polycarboxylic acids (α) and polyols (β) in its molecule. Such polyester (A) is usually obtained by ester bonding of polycarboxylic acids (α) and polyols (β).

[0060] In addition, as the aforementioned polyester (A), examples include polyester (A1) having structural units derived from polycarboxylic acids (α), structural units derived from polyols (β), and structural units derived from compounds (B) having photoreactive groups, and polyester (A2) having structural units derived from polycarboxylic acids (α) and structural units derived from polyols (β) but not having structural units derived from compounds (B) having photoreactive groups.

[0061] This composition 1 contains the aforementioned polyester (A1). By containing polyester (A1), it exhibits excellent curability, adhesion, holding power, adhesiveness, and thermal stability under active energy rays.

[0062] In addition, from the viewpoints of adhesiveness, holding power and thermal stability, this composition 1 preferably also contains a polyester resin (A2).

[0063] Composition 2 contains polyester (A), and the polyester (A) contained in composition 2 is preferably a polyester (A2) that does not contain photoreactive groups.

[0064] The aforementioned polyester (A) content is 50% or more by mass of the total composition, more preferably 60 to 99.5% by mass, even more preferably 70 to 99% by mass, particularly preferably 80 to 98.5% by mass, and especially preferably 85 to 98% by mass.

[0065] The aforementioned polyester (A1) content is typically 50% by mass or more of polyester (A), more preferably 60% by mass or more, even more preferably 70% by mass, particularly preferably 80% by mass or more, and may also be 100% by mass.

[0066] Furthermore, when this composition contains polyester (A1) and polyester (A2), the mass ratio [(A1) / (A2)] is typically 99 / 1 to 1 / 99, preferably 90 / 10 to 5 / 95, more preferably 80 / 20 to 10 / 90, even more preferably 70 / 30 to 15 / 85, and particularly preferably 60 / 40 to 20 / 80. When these mass ratios are within the aforementioned ranges, there is a tendency for excellent curability with active energy rays, adhesion, holding power, and thermal stability.

[0067] [Polycarboxylic acid(α)]

[0068] Examples of the aforementioned polycarboxylic acids (α) include aliphatic polycarboxylic acids (α1), aromatic polycarboxylic acids (α2), and alicyclic polycarboxylic acids (α3). One or more of the aforementioned polycarboxylic acids (α) may be used. Among them, aliphatic polycarboxylic acids (α1) are preferred because they have excellent active energy curing properties and adhesion, which can reduce the melt viscosity when the molecular weight is increased, and they have excellent coating suitability.

[0069] Examples of the aforementioned aliphatic polycarboxylic acids (α1) include malonic acid, succinic acid, glutaric acid, adipic acid, trimethyl adipic acid, pimelic acid, 3-methylglutaric acid, 2,2-dimethylglutaric acid, azelaic acid, sebacic acid, thiodipropionic acid, diethylene glycol acid, 1,9-nonanedicarboxylic acid, hydrogenated dimer acids derived from the dimerization of unsaturated monocarboxylic acids such as oleic acid, linoleic acid, linolenic acid, and erucic acid, as well as saturated aliphatic dicarboxylic acids (α1-1), fumaric acid, maleic acid, itaconic acid, and dimer acids derived from the dimerization of unsaturated monocarboxylic acids such as oleic acid, linoleic acid, linolenic acid, and erucic acid, as well as unsaturated aliphatic dicarboxylic acids (α1-2). From the viewpoint of excellent thermal stability, it is preferable to contain saturated aliphatic dicarboxylic acids (α1-1). From the viewpoint of excellent curing properties, adhesion and coating suitability of active energy rays, it is even more preferable to contain succinic acid, adipic acid, azelaic acid, sebacic acid and hydrogenated dimer acid.

[0070] Examples of the aforementioned aromatic polycarboxylic acids (α2) include, for instance, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, furan dicarboxylic acid, and thiophene dicarboxylic acid; aromatic polycarboxylic acids such as trimellitic acid, pyromellitic acid, ethylene glycol bis(triphenylamine) esters, glyceryl tri(triphenylamine) esters, pyromellitic tetracarboxylic acid, oxydiphenylcarboxylic acid, 3,3',4,4'-benzophenone tetracarboxylic acid, 3,3',4,4'-biphenyl tetracarboxylic acid, 3,3',4,4'-biphenyl sulfone tetracarboxylic acid, 4,4'-(hexafluoroisopropylidene)diphthalic acid, and 2,2'-bis[(dicarboxyphenoxy)phenyl]propane, which are aromatic polycarboxylic acids with three or more members. From the viewpoint of excellent hydrolysis resistance and cohesiveness, aromatic dicarboxylic acids are preferred, and terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, and furan dicarboxylic acid are more preferred. From the viewpoint of reducing the crystallinity of polyester and thus improving its viscosity and adhesion, isophthalic acid, phthalic acid, and furan dicarboxylic acid are especially preferred.

[0071] In addition, aromatic polycarboxylic acids (α2) also include some of the compounds (B) with photoreactive groups described later.

[0072] Examples of alicyclic polycarboxylic acids (α3) include cyclohexanedicarboxylic acids, cyclohexanediacetic acids, tetrahydrophthalic acids, and hexahydrophthalic acids.

[0073] When the polyester (A) has structural units derived from aliphatic polycarboxylic acids (α1), the content of structural units derived from aliphatic polycarboxylic acids (α1) relative to structural units derived from polycarboxylic acids (α) is preferably 20 mol% or more, more preferably 30 to 100 mol%, further preferably 40 to 98 mol%, particularly preferably 50 to 95 mol%, especially preferably 60 to 93 mol%, and most preferably 70 to 90 mol%. If the content of structural units derived from aliphatic polycarboxylic acids (α1) is too low, the curability of active energy rays will decrease, or the melt viscosity will increase, the suitability for hot melt coating will deteriorate, or the glass transition temperature will increase, and there is a tendency for insufficient adhesion and tack. If the content is too high, the cohesion will be insufficient, and there is a tendency for insufficient holding power.

[0074] When the polyester (A) has structural units derived from saturated aliphatic dicarboxylic acids (α1-1), the content of structural units derived from saturated aliphatic dicarboxylic acids (α1-1) relative to structural units derived from polycarboxylic acids (α) is preferably 20 mol% or more, more preferably 30 to 100 mol%, further preferably 40 to 98 mol%, particularly preferably 50 to 95 mol%, especially preferably 60 to 93 mol%, and most preferably 70 to 90 mol%. If the content of structural units derived from saturated aliphatic dicarboxylic acids (α1-1) is too low, the curability of active energy rays decreases, or the melt viscosity increases, the suitability for hot melt coating deteriorates, or the glass transition temperature increases, and there is a tendency for insufficient adhesion and tack. If the content is too high, the cohesive force is insufficient, and there is a tendency for insufficient holding power.

[0075] When the polyester (A) has structural units derived from unsaturated aliphatic dicarboxylic acids (α1-2), the content of structural units derived from unsaturated aliphatic dicarboxylic acids (α1-2) relative to structural units derived from polycarboxylic acids (α) is preferably 30 mol% or less, more preferably 15 mol% or less, further preferably 10 mol% or less, particularly preferably 5 mol% or less, especially preferably 3 mol% or less, and most preferably 0 mol%. If the content of structural units derived from unsaturated aliphatic dicarboxylic acids (α1-2) is too high, there is a tendency for insufficient thermal stability.

[0076] When the polyester (A) has structural units derived from aromatic polycarboxylic acids (α2), the content of structural units derived from aromatic polycarboxylic acids (α2) relative to structural units derived from polycarboxylic acids (α) is preferably 80 mol% or less, more preferably 1 to 60 mol%, further preferably 3 to 50 mol%, particularly preferably 5 to 40 mol%, especially preferably 10 to 30 mol%. If the content of structural units derived from aromatic polycarboxylic acids (α2) is too low, there is a tendency for insufficient cohesion, holding power, heat resistance, and resistance to damp heat. If the content is too high, the curability of active energy rays decreases, or the melt viscosity increases, resulting in a deterioration in the suitability of hot melt coating, or the glass transition temperature increases, resulting in insufficient adhesion and bonding strength.

[0077] When the polyester (A) has structural units derived from alicyclic polycarboxylic acids (α3), the percentage of structural units derived from alicyclic polycarboxylic acids (α3) relative to structural units derived from polycarboxylic acids (α) is preferably 80 mol% or less, more preferably 1 to 60 mol%, further preferably 3 to 50 mol%, particularly preferably 5 to 40 mol%, especially preferably 10 to 30 mol%. If the content of structural units derived from alicyclic polycarboxylic acids (α3) is too low, the cohesive strength is insufficient, and the holding power, heat resistance, and resistance to damp heat tend to become inadequate. If the content is too high, the curability of active energy rays decreases, or the melt viscosity increases, resulting in a deterioration in the suitability for hot melt coating, or the glass transition temperature increases, resulting in a tendency for insufficient tack and adhesion.

[0078] The molar ratio of structural units derived from aliphatic polycarboxylic acids (α1) to structural units derived from aromatic polycarboxylic acids (α2) is preferably 100 / 0 to 20 / 80, more preferably 99 / 1 to 40 / 60, particularly preferably 97 / 3 to 50 / 50, further preferably 95 / 5 to 60 / 40, especially preferably 93 / 7 to 65 / 35, and most preferably 90 / 10 to 70 / 30.

[0079] Furthermore, the molar ratio (of the structural units derived from aliphatic polycarboxylic acids (α1) to those derived from alicyclic polycarboxylic acids (α3) is preferably 100 / 0 to 20 / 80, more preferably 99 / 1 to 40 / 60, particularly preferably 97 / 3 to 50 / 50, further preferably 95 / 5 to 60 / 40, especially preferably 93 / 7 to 65 / 35, and most preferably 90 / 10 to 70 / 30.

[0080] Furthermore, in the aforementioned polyester (A), as structural units derived from polycarboxylic acids (α), there may be structural units of aromatic dicarboxylic acids having sulfonic acid groups, such as those derived from sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonnaphthalene-2,7-dicarboxylic acid, 5(4-sulfophenoxy)isophthalic acid, as well as structural units of aromatic dicarboxylic acid salts having sulfonate groups, such as their metal salts and ammonium salts. From the viewpoint of the hygrothermal resistance of the polyester (A), its content relative to the structural units derived from polycarboxylic acids (α) is preferably 10 mol% or less, more preferably 5 mol% or less, particularly preferably 3 mol% or less, further preferably 1 mol% or less, and most preferably 0 mol%.

[0081] [Polyol (β)]

[0082] Examples of polyols (β) include aliphatic polyols (β1), alicyclic polyols, and aromatic polyols. One or more polyols (β) may be used. Among these, aliphatic polyols (β1) are preferred due to their excellent active energy curing properties, excellent adhesion, and ability to reduce melt viscosity when used in high molecular weight polyols, resulting in excellent coating suitability.

[0083] Examples of the aforementioned aliphatic polyols (β1) include linear aliphatic polyols (β1-1) such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol; 1,2-propanediol; 2-methyl-1,3-propanediol; neopentanediol; 3-methyl-1,5-pentanediol; and 2-ethyl-2-propanediol. - Butylpropanediol, dimerized diols derived from the dimerization of unsaturated monocarboxylic acids such as oleic acid, linoleic acid, linolenic acid, and erucic acid, 2,4-diethyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, etc., are branched aliphatic polyols (β1-2) with a hydrocarbon group on at least one of their side chains.

[0084] Among these, linear aliphatic polyols (β1-1) are preferred from the viewpoint of lower glass transition temperature and excellent adhesion and tack, ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol are more preferred, and ethylene glycol, 1,3-propanediol, and 1,4-butanediol are particularly preferred.

[0085] Furthermore, among these, from the viewpoints of excellent curing properties of active energy rays, hydrolysis resistance, and excellent adhesion due to reduced crystallinity, branched aliphatic polyols (β1-2) having a hydrocarbon group on at least one of their side chains are preferred, especially 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and dimer diol.

[0086] When polyester (A) has structural units derived from linear aliphatic polyols (β1-1), the content of structural units derived from linear aliphatic polyols (β1-1) relative to structural units derived from polyol (β) is preferably 10 to 100 mol%, more preferably 20 to 95 mol%, particularly preferably 30 to 90 mol%, further preferably 35 to 85 mol%, especially preferably 40 to 80 mol%. If the content of structural units derived from linear aliphatic polyols (β1-1) is too low, there is a tendency for insufficient adhesion, tackiness, and substrate bonding; if the content is too high, the crystallinity of the polyester increases, and there is a tendency for insufficient adhesion, tackiness, and curability under active energy rays.

[0087] When the polyester (A) has structural units derived from branched aliphatic polyols (β1-2) having hydrocarbon groups on at least one of their side chains, the structural units derived from branched aliphatic polyols (β1-2) are preferably 5 to 100 mol% relative to the structural units derived from polyol (β), more preferably 10 to 90 mol%, particularly preferably 15 to 80 mol%, further preferably 20 to 70 mol%, and especially preferably 25 to 60 mol%. If the content of structural units derived from branched aliphatic polyols (β1-2) is too low, the crystallinity of the polyester increases, and there is a tendency for insufficient adhesion, tackiness, and curability under active energy rays; if the content is too high, there is a tendency for insufficient adhesion, tackiness, and substrate adhesion.

[0088] The molar ratio of structural units derived from linear aliphatic polyols (β1-1) to structural units derived from branched aliphatic polyols (β1-2) is preferably 100 / 0 to 10 / 90, more preferably 95 / 5 to 20 / 80, particularly preferably 90 / 10 to 30 / 70, further preferably 85 / 15 to 35 / 65, and especially preferably 80 / 20 to 40 / 60.

[0089] Examples of alicyclic polyols mentioned above include 1,4-cyclohexanediol, 1,4-cyclohexanediethanol, tricyclodecanediol, tricyclodecanediethanol, and spirodiol.

[0090] Examples of the aforementioned aromatic polyols include, for example, ethylene oxide adducts of p-phenylenediol, isophenylenediol, o-phenylenediol, 1,4-phenylene glycol, bisphenol A, bisphenol B, bisphenol E, bisphenol F, bisphenol AP, bisphenol BP, bisphenol P, bisphenol PH, bisphenol S, bisphenol Z, 4,4'-dihydroxybenzophenone, bisphenol fluorene, and other bisphenols, their hydrides, as well as ethylene oxide adducts obtained by adding 1 to several moles of ethylene oxide or propylene oxide to the hydroxyl groups of bisphenols, and diols such as propylene oxide adducts.

[0091] In addition, to easily obtain polymers with the target molecular weight, the aforementioned polyols (β) can also be, for example, polyester glycol, polyether glycol, polycaprolactone glycol, polycarbonate glycol, hydrogenated polybutadiene glycol, hydrogenated polyisoprene glycol, etc.

[0092] Examples of the aforementioned polyester diols include: structural units of polyester diols obtained by dehydrating diol components such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,10-decanediol, and octadecanediol with dicarboxylic acid components such as succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanoic acid, 1,14-tetradecanoic acid, terephthalic acid, isophthalic acid, their anhydrides, or lower alkyl esters, or their derivatives, either individually or in a mixture.

[0093] Commercially available products of the aforementioned polyester glycols include, for example, polyester glycols of 3-methyl-1,5-pentanediol and adipic acid, with trade names such as "Kuraray Polyol P-510", "Kuraray Polyol P-1010", "Kuraray Polyol P-2010", "Kuraray Polyol P-3010", and "Kuraray Polyol P-5010" [all manufactured by Kuraray Co., Ltd.].

[0094] Examples of polyether glycols mentioned above include structural units derived from polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolyether glycols obtained by ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc.

[0095] Commercially available products of the aforementioned polyether glycols include, for example, polyether glycols formed by the addition of propylene glycol to propylene oxide, with trade names such as "ADEKA POLYETHER P-400", "ADEKA POLYETHER P-1000", "ADEKA POLYETHER P-2000", and "ADEKA POLYETHER P-3000" [all manufactured by ADEKA Corporation].

[0096] As for the aforementioned polycaprolactone diol, examples of structural units include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and δ-valerol.

[0097] Commercially available products of the aforementioned polycaprolactone diol include, for example, those with trade names such as "Placcel L205AL", "Placcel L212AL", "Placcel L220AL", "Placcel L220PL", and "Placcel L230AL" [all manufactured by Daicel Chemical Industries, Ltd.].

[0098] Examples of polycarbonate diols include structural units derived from polycarbonate diols such as propylene carbonate diol, hexamethylene carbonate diol, and 3-methylpentene carbonate diol, as well as polycarbonate diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and 1,9-nonanediol, obtained through alcohol removal reactions with dialkyl carbonates such as diethyl carbonate and dimethyl carbonate.

[0099] Commercially available products of the aforementioned polycarbonate diols include, for example, products under the trade names “PLACCEL CD205”, “PLACCEL LCD210”, “PLACCEL CD220”, “PLACCEL CD205PL”, “PLACCEL CD210PL”, and “PLACCEL CD220PL” [all manufactured by Daicel Chemical Industries, Ltd.].

[0100] As for the aforementioned hydrogenated polybutadiene polyols, examples include hydrogenated polybutadiene polyols and the like, which are structural units derived from the double bonds of 1,2-polybutadiene polyols, 1,4-polybutadiene polyols, etc., saturated with hydrogen or halogens.

[0101] Commercially available products of the aforementioned hydrogenated polybutadiene polyols include, for example, products under the trade names “GI-1000”, “GI-2000”, and “GI-3000” [all manufactured by Nippon Soda Co., Ltd.].

[0102] As for the aforementioned hydrogenated polyisoprene polyols, examples include hydrogenated polyisoprene polyols whose double bonds are saturated with hydrogen or halogens, etc.

[0103] Commercially available products of the aforementioned hydrogenated polyisoprene polyols include, for example, the trade name "EPOL" [the above is produced by Idemitsu Kosan Co., Ltd.].

[0104] [Polycarboxylic acids and polyols with three or more functionalities]

[0105] In the aforementioned polyester (A), to enhance the cohesiveness introduced by the branched backbone and improve the curability using active energy rays, it is preferable to have structural units derived from the aforementioned polycarboxylic acids (α) and polyols (β) that are 3 or more functionalized polycarboxylic acids and / or polyols with 3 or more functionalities. In particular, when forming a crosslinking structure using active energy rays, the polyester (A) has a branched backbone, increasing the number of crosslinking points, and thus enabling the efficient acquisition of adhesives with high cohesiveness with a low amount of active energy irradiation.

[0106] Examples of polycarboxylic acids with three or more functions include trimellitic acid, pyromellitic acid, ethylene glycol bis(triphenylene anhydride), glyceryl tri(triphenylene anhydride), trimellitic anhydride, pyromellitic dianhydride, oxydiphenyl dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic anhydride, 4,4'-(hexafluoroisopropylidene)diphenyl dianhydride, and 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride, etc.

[0107] In addition, polyols with three or more functions include, for example, glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, etc.

[0108] These polycarboxylic acids and polyols with three or more functions can each use one or two or more types.

[0109] When the aforementioned polyester (A) contains structural units derived from polycarboxylic acids and / or polyols with three or more functions as the branched backbone, the content of structural units derived from polycarboxylic acids (α) relative to structural units derived from polycarboxylic acids (α) and the content of structural units derived from polyols (β) relative to structural units derived from polyols (β) are preferably 0.1 to 5 mol%, more preferably 0.3 to 4 mol%, even more preferably 0.5 to 3 mol%, and particularly preferably 1 to 2.5 mol%. If the content of either or both is too high, the mechanical properties of the coating film formed by applying the adhesive will decrease, there is a tendency for the adhesive strength to decrease, and there is a tendency for gelation to occur during polymerization.

[0110] In the aforementioned polyester (A), when the branched backbone contains structural units derived from polycarboxylic acids and / or polyols with three or more functions, the content of structural units derived from polycarboxylic acids and / or polyols with three or more functions relative to 100% by mass of all structural units in the polyester (A) is preferably 0.1 to 3% by mass, more preferably 0.2 to 4% by mass, particularly preferably 0.3 to 3% by mass, and even more preferably 0.4 to 2% by mass and 0.5 to 1.5% by mass. If the content of structural units derived from polycarboxylic acids and / or polyols with three or more functions is too high, the mechanical properties of the coating film formed by applying the adhesive will decrease, there is a tendency for the adhesive strength to decrease, and there is a tendency for gelation to occur during polymerization.

[0111] [Compound with photoreactive groups (B)]

[0112] In addition to structural units derived from polycarboxylic acids (α) and polyols (β), the polyester (A1) contained in this composition 1 also contains structural units derived from compounds (B) having photoreactive groups, in order to enable the polyester (A1) to crosslink itself using active energy rays.

[0113] Examples of the aforementioned photoreactive groups (B) include compounds (b1) with hydrogen-abstraction photoreactive groups and compounds (b2) with cleavage-type photoreactive groups. Two or more of these can be used alone or in combination. Of these, compounds (b1) with hydrogen-abstraction photoreactive groups are preferred from the viewpoint of excellent curing properties with active energy rays. However, the aforementioned photoreactive groups exclude olefinically unsaturated groups such as vinyl, allyl, and acryloyl groups.

[0114] Furthermore, the compound (B) containing photoreactive groups used in the polyester (A1) preferably has one or more carboxyl groups and / or hydroxyl groups, particularly preferably has two or more carboxyl groups and / or hydroxyl groups, and especially preferably has two or more carboxyl groups. Having two or more carboxyl groups within the molecule, and embedding the photoreactive groups into the polyester backbone via ester bonds, is preferable due to its excellent curability against active energy rays, thermal stability, and adhesive strength. That is, the aforementioned compound (B) containing photoreactive groups is preferably the aforementioned polycarboxylic acid (α).

[0115] [Compound with hydrogen-abstracting photoreactive group (b1)]

[0116] As for the aforementioned compound (b1) with a hydrogen-abstracting photoreactive group, any compound that generates a free radical by abstracting hydrogen from a hydrogen donor through irradiation with active energy rays is acceptable, without any particular limitation, and conventionally known compounds may be used.

[0117] Examples of compounds (b1) possessing hydrogen-abstracting photoreactive groups include benzophenones (b1-1), thioxanthones (b1-2), anthraquinones (b1-3), coumarinones, and camphorquinones. These compounds may possess one or more of these groups. Among these, benzophenones (b1-1) are preferred from the viewpoint of excellent curing properties with active energy rays.

[0118] When the aforementioned polyester (A1) contains structural sites derived from compounds (b1) possessing hydrogen-abstracting photoreactive groups, the polyester (A1) itself can undergo a dehydrogenation reaction via active energy rays without requiring unsaturated groups or crosslinking agents that can react with active energy rays and / or heat. Therefore, an adhesive with excellent adhesion and holding power, as well as excellent thermal stability and suitability for hot-melt coating, can be obtained. Furthermore, the hydrogen-abstracting photoreactive groups in the polyester (A1) can function as repeatable reactive species even after use in a single photocuring reaction, allowing for further photoirradiation. Therefore, this aspect is also preferable.

[0119] There are no special limitations on the aforementioned benzophenone class (b1-1), for example, compounds represented by the following general formula (1) can be listed.

[0120]

[0121] (In formula (1), X1 to X10 may be the same or different, and represent any one of the groups composed of hydrogen group, alkyl group, alkenyl group, aryl group, aryloxy group, alkoxy group, alkoxycarbonyl group, heterocyclic group, carboxyl group, hydroxyl group, cyano group, sulfone group, amide group, acryloyloxy group, methacryloyloxy group, halogen group, acyl group, alkylamino group, etc.)

[0122] In addition, the compounds represented by general formula (1) have at least one carboxyl or hydroxyl group in the molecule.

[0123] Specifically, examples include monofunctional hydroxybenzophenones with one hydroxyl group in the molecule, such as 3-hydroxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 5-bromo-2-hydroxybenzophenone, 2-hydroxy-5-methylbenzophenone, and 4-chloro-4'-hydroxybenzophenone; monofunctional carboxylated benzophenones with one carboxyl group in the molecule, such as benzophenone-2-carboxylic acid, benzophenone-4-carboxylic acid, and 3',4'-dimethylbenzophenone-2-carboxylic acid; and 2,3,4- Polyhydroxy benzophenones, including trihydroxybenzophenone, 2,2'-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, and 2,4,4'-trihydroxybenzophenone, and polycarboxylated benzophenones, including benzophenone-2,4'-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, and 3,3',4,4'-benzophenone tetracarboxylic dianhydride, are characterized by having two or more hydroxyl groups in their molecules. Polycarboxylated benzophenones, including benzophenone-2,4'-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, and 3,3',4,4'-benzophenone tetracarboxylic dianhydride, are characterized by having two or more carboxyl groups in their molecules. Among these, polyhydroxybenzophenones and polycarboxylated benzophenones are preferred, especially polycarboxylated benzophenones, and particularly 3,3',4,4'-benzophenone tetracarboxylic dianhydride, due to their excellent esterification reactivity and excellent curing properties via active energy radiation through embedding in the main chain of polyester (A).

[0124] There are no special limitations on the aforementioned thioxanthones (b1-2), for example, the compounds shown in the following general formula (2) can be listed.

[0125]

[0126] (In formula (2), Y1 to Y8 may be the same or different, representing any one of the groups composed of hydrogen group, alkyl group, alkenyl group, aryl group, aryloxy group, alkoxy group, alkoxycarbonyl group, heterocyclic group, carboxyl group, hydroxyl group, cyano group, sulfone group, amide group, acryloyloxy group, methacryloyloxy group, halogen group, acyl group, alkylamino group, etc.)

[0127] In addition, the compounds shown in general formula (2) have at least one carboxyl or hydroxyl group in the molecule.

[0128] Specifically, examples include thioxanone-2,3-dicarboxylic acid, thioxanone-2,7-dicarboxylic acid, thioxanone-2,6-dicarboxylic acid, and 2,2',3,3'-thioxanone tetracarboxylic dianhydride.

[0129] There are no special limitations on the aforementioned anthraquinones (b1-3), for example, the compounds shown in the following general formula (3) can be listed.

[0130]

[0131] (In formula (3), Z1 to Z8 may be the same or different, representing any one of the groups composed of hydrogen group, alkyl group, alkenyl group, aryl group, aryloxy group, alkoxy group, alkoxycarbonyl group, heterocyclic group, carboxyl group, hydroxyl group, cyano group, sulfone group, amide group, acryloyloxy group, methacryloyloxy group, halogen group, acyl group, alkylamino group, etc.)

[0132] In addition, the compounds shown in general formula (3) have at least one carboxyl or hydroxyl group in the molecule.

[0133] Specifically, examples include anthraquinone-2,3-dicarboxylic acid, anthraquinone-2,7-dicarboxylic acid, anthraquinone-2,6-dicarboxylic acid, and 2,2',3,3'-anthraquinone tetracarboxylic dianhydride.

[0134] [Compounds with cleavage-type photoreactive groups (b2)]

[0135] As for the aforementioned compound (b2) with a cleavage-type photoreactive group, any compound that undergoes photocleavage and generates free radicals, for example, due to irradiation by active energy rays, is acceptable and there are no particular limitations; conventionally known compounds may be used.

[0136] Examples of compounds (b2) that possess cleavage-type photoreactive groups include benzoin derivatives, benzoyl ketals, hydroxyacetophenones, aminoacetophenones, and acylphosphine oxides. They may possess one or more of these groups.

[0137] When the aforementioned polyester (A1) contains structural sites derived from compounds (b2) possessing cleavage-type photoreactive groups, the polyester (A1) itself can react via active energy rays without requiring unsaturated groups, crosslinking agents, or the like that can react with active energy rays and / or heat. Therefore, an adhesive with excellent adhesion and holding power, as well as excellent thermal stability and suitability for hot-melt coating, can be obtained. Furthermore, the cleavage-type photoreactive groups in the polyester (A1) can function as repeatable reactive species even after use in a single photocuring reaction, allowing for further photoirradiation. Therefore, this aspect is also preferable.

[0138] The aforementioned compound (B) with photoreactive groups can be inserted into the structure of polyester (A) by chemical bonding with any functional group of polyester (A). Preferably, the structural unit of the compound (B) with photoreactive groups is inserted into the main chain of polyester (A1) by ester bond.

[0139] As a method for embedding the aforementioned compound (B) with a photoreactive group into a polyester (A), conventionally known chemical reactions can be used, wherein preferably, the functional groups of the polycarboxylic acid (α) and / or polyol (β) derived from the polyester (A) are subjected to an esterification reaction (however, excluding epoxy ester bonds formed by the reaction of epoxy groups with carboxyl groups).

[0140] In addition, when the aforementioned compound (B) with photoreactive group is a polycarboxylic acid (α), the polycarboxylic acid (α) containing the compound (B) with photoreactive group can be subjected to an esterification reaction with a polyol (β).

[0141] The content of the structural unit derived from the compound (B) having a photoreactive group relative to 100 mol% of all structural units of the polyester (A1) is preferably 0.001 to 30 mol%, more preferably 0.01 to 15 mol%, particularly preferably 0.05 to 10 mol%, further preferably 0.1 to 5 mol%, especially preferably 0.2 to 3 mol%, more preferably 0.3 to 1.5 mol%, further preferably 0.4 to 1.25 mol%, and more preferably 0.5 to 1.0 mol%. If the content of the structural unit derived from the compound (B) having a photoreactive group is too low, there is a tendency for insufficient curing properties, adhesion, and holding power of the active energy rays; if it is too high, there is a tendency for the crosslinking density of the polyester (A1) to increase, resulting in insufficient adhesion and tack, or increased melt viscosity and insufficient coating suitability.

[0142] Furthermore, the content of the structural unit derived from the compound (B) having a photoreactive group relative to 100% by mass of all structural units of the polyester (A1) is preferably 0.001 to 30% by mass, more preferably 0.01 to 15% by mass, particularly preferably 0.1 to 10% by mass, further preferably 0.2 to 5% by mass, especially preferably 0.3 to 3% by mass, most preferably 0.4 to 1.5% by mass, and even more preferably 0.5 to 1.0% by mass. If the content of the structural unit derived from the compound (B) having a photoreactive group is too low, there is a tendency for insufficient curing properties, adhesion, and holding power of the active energy rays; if it is too high, there is a tendency for the crosslinking density of the polyester (A1) to increase, resulting in insufficient adhesion and tack, or increased melt viscosity and insufficient coating suitability.

[0143] [Cyclic esters]

[0144] In addition to structural units derived from polycarboxylic acids (α), polyols (β), and compounds (B) with photoreactive groups, the aforementioned polyester (A) may also contain structural units derived from cyclic esters, within a range that does not impair the effects of the present invention, in order to adjust melt viscosity, glass transition temperature, and impart biodegradability.

[0145] Examples of the aforementioned cyclic esters include lactide, β-propiolactone, β-butyrolactone, γ-butyrolactone, γ-caprolactone, γ-octyllactone, δ-valerolactone, δ-caprolactone, δ-octyllactone, ε-caprolactone, δ-dodecyllactone, α-methyl-γ-butyrolactone, β-methyl-δ-valerolactone, and aliphatic lactones such as glycolide. Among these, ε-caprolactone is preferred due to its superior adhesive properties and biodegradability. One or more of these cyclic ester compounds may be used.

[0146] The structural units derived from cyclic esters in the aforementioned polyester (A) are preferably less than 140 mol% relative to the structural units derived from polycarboxylic acids (α) per 100 mol%, more preferably less than 100 mol%, particularly preferably less than 60 mol%, further preferably less than 30 mol%, especially preferably less than 15 mol%, and most preferably 0 mol%. If the content of structural units derived from cyclic esters is too high, there is a tendency for the polyester (A) to crystallize, resulting in reduced active energy curing properties, decreased adhesion, or increased melt viscosity, thus deteriorating the suitability for hot melt coating.

[0147] In addition, in order to adjust the melt viscosity, glass transition temperature and impart biodegradability, the aforementioned polyester (A) may contain structural units derived from compounds that simultaneously have carboxylic acids and hydroxyl groups in the molecule, within a range that does not impair the effects of the present invention.

[0148] Examples of compounds that simultaneously possess both carboxylic acids and hydroxyl groups within their molecules include glycolic acid, lactic acid, hydroxybutyric acid, and hydroxyhexanoic acid. Among these, lactic acid and hydroxybutyric acid are particularly preferred from the viewpoint of increasing ester bond concentration and providing excellent adhesion and biodegradability. These compounds, which have structural units derived from compounds simultaneously possessing both carboxylic acids and hydroxyl groups within their molecules, may use one or more of these types.

[0149] In the aforementioned polyester (A), the structural units derived from compounds simultaneously possessing carboxylic acids and hydroxyl groups within the molecule are preferably 100 mol% or less, more preferably 80 mol% or less, particularly preferably 60 mol% or less, further preferably 40 mol% or less, especially preferably 20 mol% or less, and most preferably 10 mol% or less, relative to structural units derived from polycarboxylic acids (α). If the content of structural units derived from compounds simultaneously possessing carboxylic acids and hydroxyl groups within the molecule is excessive, there is a tendency for the polyester (A) to crystallize, for its active energy curing properties to decrease, for its adhesion to decrease, or for its melt viscosity to increase, leading to a deterioration in its suitability for hot melt coating.

[0150] [Manufacturing of Polyester (A)]

[0151] The aforementioned polyester (A) can be manufactured using well-known methods.

[0152] For example, in the case of polyester (A1), a prepolymer can be obtained by esterification of a polycarboxylic acid (α), a polyol (β), and a compound (B) with a photoreactive group in the presence of a catalyst as needed, followed by polycondensation to obtain a polyester, which can then be manufactured by introducing hydroxyl or acid groups as needed.

[0153] In the case of polyester (A2), a prepolymer can be obtained by esterification of polycarboxylic acid (α) and polyol (β) in the presence of a catalyst as needed, followed by polycondensation to obtain polyester, and then hydroxyl and acid groups can be introduced as needed to manufacture it.

[0154] The temperature of the aforementioned esterification reaction is usually 180–280°C, and the reaction time is usually 60 minutes to 8 hours.

[0155] The aforementioned polycondensation temperature is typically 220–280°C, and the reaction time is typically 20 minutes to 4 hours. Furthermore, polycondensation is preferably carried out under reduced pressure.

[0156] As a method for introducing acid groups into polyester, examples include introducing carboxyl groups into polyester by acid addition or depolymerization after esterification or compression polymerization.

[0157] Among these methods, when introducing carboxyl groups at the end of the polyester main chain, depolymerization is particularly preferred for the purpose of efficiently introducing carboxyl groups.

[0158] In addition, when introducing carboxyl groups into the side chains of polyester, acid addition is preferred.

[0159] When introducing carboxyl groups to the main chain end of polyester using the aforementioned depolymerization method, if it is polyester (A1), for example, polycarboxylic acid (α), polyol (β), and compound (B) with photoreactive groups can be esterified in the presence of a catalyst to obtain a prepolymer, followed by polycondensation and then depolymerization.

[0160] Alternatively, if it is a polyester (A2), for example, polycarboxylic acids (α) and polyols (β) can be esterified in the presence of a catalyst to obtain a prepolymer, followed by polycondensation and then depolymerization.

[0161] For depolymerization, polycarboxylic acids with three or more nucleotides having an anhydride number of 0 or 1 are preferred in terms of adhesive strength. Examples of polycarboxylic acids with three or more nucleotides having an anhydride number of 0 or 1 include trimellitic acid, trimellitic anhydride, hydrogenated trimellitic anhydride, and pyromellitic acid. From the viewpoint of suppressing molecular weight reduction, polycarboxylic acids with three or more nucleotides having an anhydride number of 1 are preferred, such as trimellitic anhydride and hydrogenated trimellitic anhydride, with trimellitic anhydride being particularly preferred.

[0162] The depolymerization temperature is usually 200–260°C, and the reaction time is usually 10 minutes to 3 hours.

[0163] When polyester (A) is manufactured using the depolymerization method, if the content of structural units of polycarboxylic acids of 3 or more with an anhydride number of 0 or 1 exceeds 20 mol% relative to the content of structural units of polycarboxylic acids (α) at ​​100 mol%, the molecular weight of the resin tends to decrease significantly.

[0164] Therefore, the content of structural units derived from polycarboxylic acids (α) with an anhydride number of 0 or 1 is preferably 20 mol% or less, more preferably 1 to 15 mol%, particularly preferably 2 to 10 mol%, and even more preferably 3 to 8 mol%, relative to 100 mol% of structural units derived from polycarboxylic acids (α).

[0165] When introducing carboxyl groups into the side chains of polyester using the aforementioned acid addition method, for example, polycarboxylic acids (α) other than polycarboxylic anhydrides, polyols (β), and compounds (B) with photoreactive groups can be esterified to obtain a prepolymer. The obtained hydroxyl-containing prepolymer is then reacted with a polycarboxylic anhydride to undergo acid addition. Furthermore, in the acid addition method, if monocarboxylic acids, dicarboxylic acids, or polyfunctional carboxylic acid compounds are used, the molecular weight may decrease due to transesterification; therefore, compounds having at least one carboxylic anhydride are preferred.

[0166] In addition, as methods for depolymerization and acid addition, examples include direct addition in the bulk state and addition by solidifying the polyester.

[0167] The aforementioned block reaction is fast, but if a large amount is added, gelation may occur, and the reaction may occur at high temperatures. Therefore, it is necessary to block oxygen and prevent oxidation.

[0168] On the other hand, addition reactions in solution are slow but can stably introduce large amounts of carboxyl groups.

[0169] Examples of the aforementioned polycarboxylic anhydrides include succinic anhydride, maleic anhydride, phthalic anhydride, 2,5-norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic dianhydride, oxydiphthalic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyl sulfone tetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride, and 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride, etc.

[0170] When manufacturing polyester (A) by acid addition, gelation may occur if more than 15 mol% of acid addition is performed relative to 100 mol% of structural units derived from polycarboxylic acids (α). Therefore, it is preferable to perform acid addition at less than 15 mol%.

[0171] [Composition ratio of polyester (A)]

[0172] The proportions (composition ratios) of the aforementioned polyester (A) derived from the structural sites of its various components can be determined using known NMR methods, such as NMR at a resonance frequency of 400 MHz. 1 H-NMR measurement (proton-type nuclear magnetic resonance spectrometry) 13 It is determined by C-NMR determination (carbon-type nuclear magnetic resonance spectrometry) and other methods.

[0173] [Glass transition temperature of polyester (A)]

[0174] The glass transition temperature of the aforementioned polyester (A) is preferably -80 to 30°C, more preferably -75 to 10°C, further preferably -70 to -10°C, especially preferably -65 to -20°C, further preferably -60 to -30°C, particularly preferably -55 to -35°C, and most preferably -50 to -40°C. If the glass transition temperature is too high, the viscosity and adhesion will become insufficient, or the melt viscosity will increase, and the suitability for hot melt coating will tend to deteriorate. If the glass transition temperature is too low, the holding power and heat resistance will tend to become insufficient.

[0175] The method for determining the glass transition temperature is as follows.

[0176] The glass transition temperature can be determined using a differential scanning calorimeter. The measurement conditions are: a temperature range of -90 to 100°C and a temperature rise rate of 10°C / minute.

[0177] [Acid value of polyester (A)]

[0178] The acid value of the aforementioned polyester (A) is preferably 30 mg KOH / g or less, more preferably 10 mg KOH / g or less, particularly preferably 5 mg KOH / g or less, further preferably 3 mg KOH / g or less, especially preferably 1 mg KOH / g or less, and most preferably 0.5 mg KOH / g or less. If this acid value is too high, the resistance to damp heat becomes insufficient, or the heat resistance decreases, and it tends to undergo thermal decomposition easily.

[0179] The definition and determination method of acid value are as follows.

[0180] The acid value (mgKOH / g) can be determined by neutralizing and titrating 1g of polyester (A) in 30g of a toluene / methanol mixture (e.g., toluene / methanol = 7 / 3 by volume) according to JIS K 0070.

[0181] In addition, in this invention, the acid value of polyester (A) is due to the content of carboxyl groups in the resin.

[0182] [Hydroxy value of polyester (A)]

[0183] The hydroxyl value of the aforementioned polyester (A) is preferably below 50 mg KOH / g, particularly preferably 1 to 30 mg KOH / g, more preferably 2 to 20 mg KOH / g, further preferably 3 to 15 mg KOH / g, especially preferably 4 to 10 mg KOH / g, and most preferably 5 to 8 mg KOH / g. If this hydroxyl value is too high, the curing properties of the active energy rays will decrease, or the cohesiveness and holding power will become insufficient. If it is too low, the adhesiveness and adhesion will become insufficient, or the compatibility with the adhesive resin will be poor.

[0184] The hydroxyl value of the aforementioned polyester (A) was determined by neutralization titration according to JIS K 0070.

[0185] [Isocyanate concentration of polyester (A)]

[0186] The isocyanate concentration of the aforementioned polyester (A) is preferably 5% or less, more preferably 3% or less, further preferably 1% or less, particularly preferably 0.5% or less, especially preferably 0.3% or less, and most preferably 0.1% or less. Furthermore, the lower limit is 0%, and it is preferable to have no isocyanate groups. If this isocyanate concentration is too high, the reaction may occur due to the heat load during the manufacturing of the polyester (A) and during hot-melt coating, tending to result in poor pot life, poor coating appearance, or reduced adhesion.

[0187] [Ethylene oxide oxygen concentration in polyester (A)]

[0188] The ethylene oxide oxygen concentration of the aforementioned polyester (A) is preferably 5% or less, more preferably 3% or less, further preferably 1% or less, particularly preferably 0.5% or less, especially preferably 0.3% or less, and most preferably 0.1% or less. Furthermore, the lower limit is 0%, and it is preferable to have no ethylene oxide oxygen (epoxy group). If this ethylene oxide oxygen concentration is too high, the reaction may occur due to the heat load during the manufacturing of the polyester (A) and during hot melt coating, resulting in poor pot life, poor coating appearance, or reduced adhesion.

[0189] The ethylene oxide oxygen concentration of the aforementioned polyester (A) can be determined by titration with an acetic acid solution of hydrogen bromide according to ASTM-1652.

[0190] [Ester bond concentration of polyester (A)]

[0191] The ester bond concentration of the aforementioned polyester (A) is preferably 2–14 mmol / g, more preferably 3–13 mmol / g, further preferably 4–12 mmol / g, particularly preferably 5–11 mmol / g, especially preferably 5.5–10 mmol / g, and most preferably 6–9 mmol / g. If the ester bond concentration is too high, the melt viscosity tends to increase, and the coating suitability becomes insufficient. If the ester bond concentration is too low, the heat resistance, substrate adhesion, and bonding strength tend to become insufficient.

[0192] The definition and determination method of ester bond concentration are as follows.

[0193] The ester bond concentration (mmol / g) is the number of moles of ester bonds in 1g of polyester (A), which can be calculated, for example, from the feed amount. This calculation method is to divide the smaller mole of either the polycarboxylic acid (α) or the polyol (β) by the total mass of the polyester (A), as shown in the example below.

[0194] In addition, when the feed amounts of polycarboxylic acids (α) and polyols (β) are the same molar amount, any of the following calculation formulas can be used.

[0195] In addition, when using monomers that simultaneously possess carboxyl and hydroxyl groups, or when polyesters are made from caprolactone, the calculation method should be appropriately modified.

[0196] (The case where there is less polycarboxylic acid (α) than polyol (β))

[0197] Ester concentration (mmol / g) = [(P1 / p1×m1 + P2 / p2×m2 + P3 / p3×m3···) / Z]×1000

[0198] P: Feed rate (g) of polycarboxylic acid (α)

[0199] p: Molecular weight of polycarboxylic acid (α)

[0200] m: Number of carboxyl groups per molecule of a polycarboxylic acid (α)

[0201] Z: Finished product weight (g)

[0202] (When there is less polyol (β) than polycarboxylic acid (α))

[0203] Ester concentration (mmol / g) = [(Q1 / q1×n1 + Q2 / q2×n2 + Q3 / q3×n3···) / Z]×1000

[0204] Q: Feed rate (g) of polyol (β)

[0205] q: Molecular weight of the polyol (β)

[0206] n: The number of hydroxyl groups per molecule of a polyol (β).

[0207] Z: Finished product weight (g)

[0208] The aforementioned ester bond concentration can also be determined using known methods such as NMR, for example, using a resonant frequency of 400 MHz. 1 H-NMR measurement (proton-type nuclear magnetic resonance spectrometry) 13 The determination is performed using C-NMR (carbon-type nuclear magnetic resonance spectrometry).

[0209] [Concentration of unsaturated groups in polyester (A)]

[0210] The concentration of unsaturated groups in the aforementioned polyester (A) is preferably less than 1.5 mmol / g relative to 1g of polyester (A), more preferably less than 1.0 mmol / g, particularly preferably less than 0.5 mmol / g, further preferably less than 0.3 mmol / g, especially preferably less than 0.1 mmol / g, and most preferably less than 0.01 mmol / g. Furthermore, the lower limit is 0 mmol / g. If the concentration of unsaturated groups in the polyester (A) is too high, the unsaturated groups may react due to the heat load during the manufacturing of the polyester (A) and during hot melt coating, resulting in poor pot life, poor coating appearance, or reduced adhesion. The concentration of unsaturated groups contained in the aforementioned polyester (A) can be determined from the utilization... 1 H-NMR measurement, 13 The spectrum obtained from C-NMR measurements was used to determine the spectral composition.

[0211] [Epoxy group concentration of polyester (A)]

[0212] The epoxy group concentration of the aforementioned polyester (A) is preferably 5 mmol / g or less relative to 1g of polyester (A), more preferably 3 mmol / g or less, particularly preferably 2 mmol / g or less, further preferably 1 mmol / g or less, especially preferably 0.5 mmol / g or less, and most preferably 0.1 mmol / g or less. Furthermore, the lower limit is 0 mmol / g. If the epoxy group concentration of the polyester (A) is too high, the epoxy group may react due to the heat load during the manufacturing of the polyester (A) and during hot melt coating, resulting in poor pot life, poor coating appearance, or reduced adhesion.

[0213] In addition, the epoxy group concentration can be obtained by taking the reciprocal of the epoxy equivalent calculated according to JIS K 7236.

[0214] [Peak molecular weight (Mp), number-average molecular weight (Mn), and weight-average molecular weight (Mw) of polyester (A)]

[0215] The peak molecular weight (Mp) of the aforementioned polyester (A) is preferably 5,000 to 150,000, more preferably 10,000 to 120,000, particularly preferably 20,000 to 100,000, further preferably 30,000 to 90,000, and especially preferably 40,000 to 80,000.

[0216] If the peak molecular weight (Mp) is too low, the curability of the active energy rays will decrease, or the cohesiveness will be insufficient, and the heat resistance and damp heat durability will become inadequate. Conversely, if the peak molecular weight (Mp) is too high, the adhesion and bonding strength will become insufficient, or the melt viscosity will increase, resulting in inadequate coating suitability.

[0217] The number average molecular weight (Mn) of the aforementioned polyester (A) is preferably 1,000 to 150,000, more preferably 2,500 to 120,000, particularly preferably 5,000 to 100,000, even more preferably 10,000 to 80,000, and especially preferably 20,000 to 60,000.

[0218] If the number-average molecular weight (Mn) is too low, the curing properties of active energy rays will decrease, or the cohesiveness will be insufficient, and the heat resistance and damp heat durability will become inadequate. On the other hand, if the number-average molecular weight (Mn) is too high, the adhesion and bonding strength will become insufficient, the melt viscosity will increase, and the coating suitability will become inadequate.

[0219] The weight-average molecular weight (Mw) of the aforementioned polyester (A) is preferably 5,000 to 500,000, more preferably 10,000 to 300,000, particularly preferably 20,000 to 200,000, further preferably 30,000 to 150,000, especially preferably 50,000 to 130,000, and most preferably 70,000 to 110,000.

[0220] If the weight-average molecular weight (Mw) is too low, the curing properties of active energy rays will decrease, or the cohesiveness will be insufficient, and the heat resistance and damp heat durability will become inadequate. On the other hand, if the weight-average molecular weight (Mw) is too high, the substrate adhesion and bonding strength will become insufficient, or the melt viscosity will increase, resulting in inadequate coating suitability.

[0221] The methods for determining peak molecular weight (Mp), number-average molecular weight (Mn), and weight-average molecular weight (Mw) are described below.

[0222] Peak molecular weight (Mp), number-average molecular weight (Mn), and weight-average molecular weight (Mw) can be determined by high-performance liquid chromatography (HLC-8320GPC, manufactured by Tosoh Corporation) using a TSKgel SuperMultipore HZ-M column (size exclusion limit molecular weight: 2 × 10⁻⁶). 6Theoretical plate number: 16,000 / plate; packing material: styrene-divinylbenzene copolymer; packing particle size: 4μm) ) 2 plates were connected in series for measurement, and the molecular weight was calculated using standard polystyrene.

[0223] The polydispersity of the aforementioned polyester (A) is preferably 0.5 or higher, more preferably 1 to 30, particularly preferably 1.5 to 20, further preferably 2 to 15, especially preferably 2.5 to 10, and most preferably 3 to 8. If the dispersity is too low, there is a tendency for reduced curability to active energy rays, or insufficient cohesiveness, resulting in inadequate heat resistance and damp heat durability. If the dispersity is too high, there is a tendency for insufficient adhesion and bonding strength, or increased melt viscosity, resulting in inadequate coating suitability. The polydispersity is calculated using the following formula.

[0224] Polydispersity = Weight-average molecular weight (Mw) / Number-average molecular weight (Mn)

[0225] The melt viscosity (at 130°C) of the aforementioned polyester (A) is preferably 500 Pa·s or less, more preferably 1 to 400 Pa·s, further preferably 3 to 300 Pa·s, particularly preferably 5 to 200 Pa·s, especially preferably 10 to 150 Pa·s, and most preferably 15 to 100 Pa·s. If the melt viscosity is too low, the heat resistance, holding power, adhesion, and damp heat durability tend to become insufficient; if it is too high, the coating appearance tends to show streaks, and the coating suitability tends to become insufficient.

[0226] Furthermore, when the aforementioned polyester (A) is a polyester (A1) containing photoreactive groups, its melt viscosity (at 160°C) is preferably 200 Pa·s or less, more preferably 1 to 150 Pa·s, even more preferably 2 to 100 Pa·s, particularly preferably 3 to 80 Pa·s, especially preferably 4 to 60 Pa·s, and most preferably 5 to 40 Pa·s. If the melt viscosity is too low, the heat resistance, holding power, adhesion, and damp heat durability tend to become insufficient; if it is too high, the coating appearance tends to show streaks, and the coating suitability tends to become insufficient.

[0227] The method for determining melt viscosity is as follows.

[0228] The melt viscosity of polyester extruded from the nozzle was determined using a flow tester “CFT-500EX” (manufactured by Shimadzu Corporation) under the following conditions: constant temperature method at test temperature of 130°C or 160°C, residence time of 3 minutes, test force of 30 (load of 3 kg), die diameter of 1.0 mm, die length of 10 mm, and stroke of 20 mm.

[0229] From the viewpoint of thermal stability and coating suitability, the aforementioned polyester (A) preferably exhibits a small rate of change in melt viscosity before and after a thermal process (200°C × 3 hours, under air conditions). The rate of change in melt viscosity is preferably 20–500%, more preferably 30–400%, further preferably 40–300%, particularly preferably 50–250%, especially preferably 60–200%, and most preferably 70–150%. If the rate of change in melt viscosity before and after the thermal process is outside the aforementioned range, there is a tendency for the adhesive to gel or decompose, resulting in insufficient coating suitability, or insufficient adhesion and bonding strength.

[0230] Furthermore, the fact that the aforementioned polyester (A) is a non-crystalline polyester is preferable in terms of its curability under active energy rays, viscosity, and optical properties. Conversely, if the polyester (A) is crystalline, its curability under active energy rays, viscosity, molding stability, and optical properties tend to become insufficient.

[0231] The aforementioned non-crystallization can be confirmed using differential scanning calorimetry, for example, by the absence of an endothermic peak caused by crystallization melting when measured within a temperature range of -90 to 400°C and a temperature rise rate of 10°C / min. Furthermore, the measurement temperature range and heating rate can be appropriately adjusted based on the sample.

[0232] The aforementioned polyester (A) has a heat of fusion of 0 J / g, which is preferred in terms of curability, viscosity, and optical properties from the perspective of active energy ray curing. However, in the case of crystallization, it is 50 J / g or less, preferably 30 J / g or less, especially preferably 10 J / g or less, particularly preferably 5 J / g or less, more preferably 3 J / g or less, and most preferably 1 J / g or less.

[0233] In addition, in order to reduce the burden on the Earth's environment, the aforementioned polyester (A) is preferably composed of plant-derived raw materials and has a biomass content.

[0234] The biomass content of the aforementioned polyester (A) is preferably 10% or more, more preferably 20% or more, particularly preferably 30% or more, further preferably 40% or more, especially preferably 50% or more, and most preferably 60% or more. Furthermore, the upper limit is 100%. If this biomass content is low, there is a tendency for the reduction of the environmental impact to become insufficient.

[0235] Here, the biomass degree of the aforementioned polyester (A) refers to the mass ratio of the portion of plant-derived raw materials embedded in the resin used in the manufacture of the aforementioned polyester (A) to the total mass of the polyester (A), and its calculation method is as follows. Furthermore, the biomass degrees of the polycarboxylic acid (α) and polyol (β) are obtained from a weighted average of their respective biomass degrees. Additionally, in the following calculation methods, any value obtained by any method is acceptable as long as it falls within the aforementioned range.

[0236] (Calculation method)

[0237] Biomass content (%) = [(moles of carbon from plant-derived monomers calculated from the molar ratio of polycarboxylic acids (α) and polyols (β) in polyester (A)) / (moles of carbon from all constituent monomers in polyester (A))] × 100

[0238] Alternatively, the aforementioned biomass quality can also be determined by resolving the composition ratio using NMR and calculating the carbon number of the individual derived from the plant / the total carbon number.

[0239] In addition, the aforementioned biomass quality can also be determined using the method described in the Tokyo Metropolitan Industrial Technology Research Center Research Report No. 4, 2009, "Source Identification Technology for Biofuels Using Natural Radioactive Carbon C-14".

[0240] <Compounds with photoreactive groups (B)>

[0241] To improve the crosslinking efficiency of the polyester (A) based on active energy rays, the composition 1 may also contain the aforementioned compound (B) having photoreactive groups.

[0242] Furthermore, this composition 2 contains a compound (B) having a photoreactive group. Because this composition 2 contains a compound (B) having a photoreactive group, it exhibits excellent active energy ray curing properties even without unsaturated groups or crosslinking agents.

[0243] The compound (B) contained in this composition, which has a photoreactive group, acts as a photopolymerization initiator.

[0244] Compounds (B) that function as photopolymerization initiators and have photoreactive groups include, for example, compounds (b1) [hydrogen-abstracting photopolymerization initiators] having hydrogen-abstracting photoreactive groups and compounds (b2) [cleavage-type photopolymerization initiators] having cleavage-type photoreactive groups. They may have one or more of these groups.

[0245] Among them, from the viewpoint of excellent curing properties of active energy rays, compounds (b1) with hydrogen-abstracting photoreactive groups are preferred [hydrogen-abstracting photopolymerization initiators].

[0246] Furthermore, the compound (B) having a photoreactive group is preferably a compound (b1) having a hydrogen-abstracting photoreactive group and / or a compound (b2) having a cleavage-type photoreactive group. If at least one of the compound (b1) having a hydrogen-abstracting photoreactive group and the compound (b2) having a cleavage-type photoreactive group is present, it is more preferably in terms of excellent curing properties with active energy rays.

[0247] Furthermore, when using a compound (B) with photoreactive groups as a photopolymerization initiator, the presence of the compound (B) with photoreactive groups independently within the composition, rather than being incorporated into the structure of the polyester (A) through chemical bonding, is preferable in terms of excellent optical properties after curing with active energy rays, ease of crosslinking control, and excellent stability. Therefore, when using a compound (B) with photoreactive groups as a photopolymerization initiator, the absence of active hydrogen groups such as carboxyl or hydroxyl groups is preferable in terms of excellent curability with active energy rays.

[0248] Examples of compounds (b1) [hydrogen-abstracting photopolymerization initiators] that possess hydrogen-abstracting photoreactive groups include benzophenones (b1-1), thioxanthones (b1-2), anthraquinones (b1-3), coumarinones, and camphorquinones. These can be used alone or in combination of two or more. Among these, benzophenones (b1-1) are preferred for their excellent curing properties against active energy rays.

[0249] The benzophenones (b1-1) that can be used as photopolymerization initiators are not particularly limited, and examples include benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, methyl o-benzoylbenzoate, 3,3'-dimethyl-4-methoxybenzophenone, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 4-morpholine benzophenone, 4,4'-diphenoxybenzophenone, 4-hydroxybenzophenone, and 2-carboxybenzophenone. Among these, benzophenone and 4-methylbenzophenone are preferred in terms of excellent curing properties under active energy radiation.

[0250] Commercially available products of this type of benzophenone (b1-1) that can be used as photopolymerization initiators include, for example, products under the trade names “Omnirad BP Flakes”, “Omnirad 4MBZ Flakes”, “Omnipol PB”, “Esacure TZT”, “Esacure TZM”, “Omnirad 4PBZ”, “Omnirad 81”, “Omnirad BMF”, and “Omnirad OMBB” [all manufactured by IGMREJINS].

[0251] There are no particular limitations on the thioxanones (b1-2) that can be used as photopolymerization initiators, such as 2-chlorothioxanone, 2,4-dimethylthioxanone, 2,4-diethylthioxanone, 2,4-diisopropylthioxanone, etc.

[0252] There are no particular limitations on the anthraquinones (b1-3) that can be used as photopolymerization initiators, for example, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, etc.

[0253] In addition, examples of compounds (b2) [cracked photopolymerization initiators] with cleavage-type photoreactive groups that can be used as photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethyl-1-one, 1-hydroxycyclohexylphenyl one, 2-hydroxy-2-methyl-1-phenyl-prop-1-one, 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxy-2-methyl-1-prop-1-one, 2-hydroxy-1-[4-{4-(2-hydroxy-2-methyl-propanoyl)benzyl}phenyl]-2-methyl-prop-1-one, and oligomeric (2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone). Methyl phenylglyoxylate, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)but-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylprop-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)2,4,4-trimethylpentylphosphine oxide, or derivatives thereof.

[0254] Commercially available products containing cleavage-type photoreactive groups that can be used as photopolymerization initiators include, for example, products under the trade names “Omnirad 651”, “Omnirad 184”, “Omnirad 1173”, “Omnirad 2959”, “Omnirad 127”, “Omnirad 907”, “Omnirad 369”, and “Omnirad TPO H” [all manufactured by IGMREJINS].

[0255] When using a compound (B) with photoreactive groups as a photopolymerization initiator, its content relative to 100 parts by mass of polyester (A) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 9 parts by mass, further preferably 0.3 to 8 parts by mass, particularly preferably 0.5 to 7 parts by mass, especially preferably 1 to 6 parts by mass, and most preferably 1.5 to 5.5 parts by mass. If this content is too high, the cohesion of the adhesive layer after curing with active energy rays tends to be too high, and the adhesion tends to be low; if it is too low, the curability of active energy rays tends to be low, and the adhesion and cohesion tend to be insufficient.

[0256] Furthermore, when using a compound (b1) with a hydrogen-abstracting photoreactive group as a photopolymerization initiator, its content relative to 100 parts by mass of polyester (A) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 9 parts by mass, even more preferably 0.3 to 8 parts by mass, particularly preferably 0.5 to 7 parts by mass, especially preferably 1 to 6 parts by mass, and most preferably 1.5 to 5.5 parts by mass. If this content is too high, the cohesiveness of the adhesive cured by the active energy rays tends to be too high, and the adhesive strength tends to be low; if it is too low, the curability of the active energy rays tends to be low, and the adhesive strength and cohesiveness tend to be insufficient.

[0257] In addition, as adjuvants to enhance the reactivity of compound (B) with photoreactive groups, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (milchone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, ethyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy) ester, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanone, and 2,4-diisopropylthioxanone, etc., can also be used in combination. These adjuvants can be used alone or in combination of two or more.

[0258] <Compounds containing unsaturated groups (C)>

[0259] To enhance cohesion, this composition may also contain a compound (C) containing unsaturated groups, which is a component that is cured by active energy rays. Examples of such compounds containing unsaturated groups include urethane (meth)acrylate compounds and olefinically unsaturated monomers having olefinically unsaturated groups.

[0260] The aforementioned urethane (meth)acrylate compounds are (meth)acrylate compounds with urethane bonds in the molecule, which can be produced by reacting hydroxyl-containing (meth)acrylate compounds with polyisocyanate compounds and polyols as needed.

[0261] Examples of hydroxyl-containing (meth)acrylic acid compounds include 2-hydroxyethyl (meth)acrylic acid, 2-hydroxypropyl (meth)acrylic acid, 2-hydroxybutyl (meth)acrylic acid, 4-hydroxybutyl (meth)acrylic acid, 6-hydroxyhexyl (meth)acrylic acid, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylic acid, caprolactone-modified 2-hydroxyethyl (meth)acrylic acid, pentaerythritol tri(meth)acrylic acid, dipentaerythritol penta(meth)acrylic acid, caprolactone-modified dipentaerythritol penta(meth)acrylic acid, caprolactone-modified pentaerythritol tri(meth)acrylic acid, ethylene oxide-modified dipentaerythritol penta(meth)acrylic acid, and ethylene oxide-modified pentaerythritol tri(meth)acrylic acid. Among these, hydroxyl-containing (meth)acrylic acid compounds having three or more acryloyl groups are preferred. In addition, one or more of them can be used in combination.

[0262] There are no specific limitations on the aforementioned polyisocyanate compounds. Examples include aromatic, aliphatic, and alicyclic polyisocyanates, such as toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, hydrogenated phenylmethylene diisocyanate, phenylmethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylphenylmethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis(isocyanoxymethyl)cyclohexane, phenyl diisocyanate, lysine diisocyanate, lysine triisocyanate, naphthalene diisocyanate, etc., or trimer or polymer compounds of these polyisocyanates, biuret-type polyisocyanates, or reaction products of these polyisocyanates with polyols, etc.

[0263] There are no particular limitations on such polyols, and examples include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butanediol, polybutanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanediol, hydrogenated bisphenol A, polycaprolactone, trimethylolethane, trimethylolpropane, polytrimethylolpropane, pentaerythritol, polypentaerythritol, sorbitol, mannitol, glycerol, polyglycerol, polytetramethylene glycol, etc. Alcohols; polyether polyols having at least one structure of ethylene oxide, polypropylene oxide, or block or random copolymers of ethylene oxide / propylene oxide; polyester polyols, which are condensates of the polyol or polyether polyol with maleic anhydride, maleic acid, fumaric acid, itaconic anhydride, itaconic acid, adipic acid, isophthalic acid, etc.; caprolactone-modified polyols such as caprolactone-modified polytetramethylene polyol; polyolefin polyols; and polybutadiene polyols such as hydrogenated polybutadiene polyol.

[0264] Other examples of such polyols include: 2,2-bis(hydroxymethyl)butyric acid, tartaric acid, 2,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxyethyl)propionic acid, 2,2-bis(hydroxypropyl)propionic acid, dihydroxymethylacetic acid, bis(4-hydroxyphenyl)acetic acid, 4,4-bis(4-hydroxyphenyl)valerate, homogentisic acid, and other carboxyl-containing polyols; and 1,4-butanediol sulfonate and other polyols containing sulfonic acid groups or sulfonate groups.

[0265] There are no particular limitations on the method for producing the aforementioned urethane (meth)acrylate compounds. For example, a method can be described by mixing a hydroxyl-containing (meth)acrylate compound with a polyisocyanate compound in an inert gas atmosphere, typically reacting at 30–80°C for 2–10 hours. In this reaction, urethane esterification catalysts such as tin octenate, di-n-butyltin dilaurate, lead octanoate, potassium octanoate, potassium acetate, stannous octanoate, and triethylenediamine are preferred.

[0266] Furthermore, when using the reaction product with the polyol as a urethane (meth)acrylate compound, for example, the reaction product obtained by reacting the aforementioned polyol and the aforementioned polyisocyanate compound can be reacted with a hydroxyl-containing (meth)acrylate compound. In this reaction between the polyisocyanate compound and the polyol, in order to promote the reaction, it is also preferable to use a metal catalyst such as dibutyltin dilaurate or an amine catalyst such as 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0267] The weight-average molecular weight of the urethane (meth)acrylate compounds is preferably 300 to 10,000, more preferably 500 to 5,000, particularly preferably 750 to 4,000, especially preferably 1,000 to 3,500, and most preferably 1,250 to 3,000. Furthermore, the method for determining the weight-average molecular weight is the same as described above.

[0268] Examples of olefinically unsaturated monomers having olefinically unsaturated groups include monofunctional monomers having one olefinically unsaturated group in one molecule, difunctional monomers having two olefinically unsaturated groups in one molecule, and monomers having three or more olefinically unsaturated groups in one molecule.

[0269] Examples of the aforementioned monofunctional monomers include styrene, vinyltoluene, chlorostyrene, α-methylstyrene, methyl methacrylate, ethyl methacrylate, acrylonitrile, vinyl acetate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, phenoxyethyl methacrylate, 2-phenoxy-2-hydroxypropyl methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, glyceryl mono(meth)acrylate, glycidyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, tricyclodecyl methacrylate, dicyclopentenyl methacrylate, n-butyl methacrylate, hexyl methacrylate, and so on. Heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, isodecyl acrylate, dodecyl acrylate, stearyl acrylate, benzyl acrylate, phenol ethylene oxide modified acrylate, nonylphenol propylene oxide modified acrylate, 2-(meth)acryloyloxy-2-hydroxypropyl phthalate and other phthalic acid derivatives half esters (meth)acrylate, furan methyl (meth)acrylate, carbitol (meth)acrylate, benzyl acrylate, butoxyethyl acrylate, allyl acrylate, acryloylmorpholine, 2-hydroxyethyl acrylamide, N-hydroxymethyl (meth)acrylamide, N-vinylpyrrolidone, 2-vinylpyridine, 2-(meth)acryloyloxyethyl acid phosphate monoester, etc.

[0270] Examples of the aforementioned difunctional monomers include 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, butanediol 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, glycerol di(meth)acrylate, pentaerythritol di(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, diglycidyl phthalate diglycidyl ester di(meth)acrylate, hydroxypentanoic acid modified neopentyl glycol di(meth)acrylate, ethylene oxide modified isocyanurate diacrylate, 2-(meth)acryloyloxyethyl acid phosphate diester, etc.

[0271] Examples of monomers with three or more functions include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tri(meth)acryloyloxyethoxytrimethylolpropane, glycerol polyglycidyl ether poly(meth)acrylate, ethylene oxide-modified tri(meth)acrylate of isocyanuric acid, 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, and succinic acid-modified pentaerythritol tri(meth)acrylate.

[0272] In addition to the aforementioned, as olefinic unsaturated monomers, examples include Michael adducts of (meth)acrylic acid or monoesters of 2-(meth)acryloyloxyethyl dicarboxylic acid. Examples of Michael adducts of (meth)acrylic acid include (meth)acrylic acid dimers, (meth)acrylic acid trimers, and (meth)acrylic acid tetramers. Furthermore, examples of monoesters of 2-(meth)acryloyloxyethyl dicarboxylic acid having specific substituents include 2-(meth)acryloyloxyethyl succinic acid monoester, 2-(meth)acryloyloxyethyl phthalic acid monoester, and 2-(meth)acryloyloxyethyl hexahydrophthalic acid monoester. Low-polyester acrylates can also be included.

[0273] These urethane (meth)acrylate compounds, olefinic unsaturated monomers, and other compounds containing unsaturated groups (C) can be used alone or in combination of two or more.

[0274] When composition 1 contains a compound (C) containing unsaturated groups, its content relative to 100 parts by mass of polyester (A) is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, further preferably 3 parts by mass or less, particularly preferably 2 parts by mass or less, especially preferably 1 part by mass or less, and most preferably 0 parts by mass. That is, composition 1 preferably does not contain a compound (C) containing unsaturated groups. If this content is too high, the cohesiveness of the adhesive layer after curing with active energy rays becomes too high, the elongation and adhesion become insufficient, or the viscosity increases or gels due to thermal reactions of the unsaturated groups, tending to result in insufficient heat resistance.

[0275] Furthermore, when composition 2 contains a compound (C) containing unsaturated groups, its content is less than 15 parts by mass relative to 100 parts by mass of polyester (A), preferably 10 parts by mass or less, more preferably 5 parts by mass or less, further preferably 3 parts by mass or less, particularly preferably 2 parts by mass or less, especially preferably 1 part by mass or less, and most preferably 0 parts by mass. That is, composition 2 preferably does not contain a compound (C) containing unsaturated groups. If this content is too high, the cohesion of the adhesive layer after curing with active energy rays becomes too high, the elongation and adhesion become insufficient, and due to thermal unsaturated group reactions, viscosity increases, gelation occurs, and thermal stability becomes insufficient.

[0276] <Crosslinking agent (D)>

[0277] To enhance cohesion, this composition may also contain a crosslinking agent (D). The crosslinking agent (D) can be any compound having functional groups that react with hydroxyl, carboxyl, or other functional groups contained in the polyester (A). Examples include bisphenol A-epimericol type epoxy resins, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycerol polyglycidyl ether, and other epoxy compounds, tetrahydroxy... Acridine compounds such as methylmethane-tri-β-acridinylpropionate, trimethylolpropane-tri-β-acridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-acridinyl carboxylamide), and N,N'-hexamethylene-1,6-bis(1-acridinyl carboxylamide); melamine compounds such as hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxymethyl melamine, hexapentoxymethyl melamine, and hexahexyloxymethyl melamine; melamine resins; 2, 4-Toluene diisocyanate, 2,6-Toluene diisocyanate, hydrogenated toluene diisocyanate, 1,3-phenylenedimethylene diisocyanate, 1,4-phenylenedimethylene diisocyanate, hexamethylene diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanoxymethyl)cyclohexane, tetramethylphenylenedimethylene diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, and adducts of these polyisocyanate compounds with polyols such as trimethylolpropane, these... The compounds include isocyanate compounds such as biuret and isocyanurate esters; aldehyde compounds such as glyoxal, malondialdehyde, succinaldehyde, maleic anhydride, glutaraldehyde, formaldehyde, acetaldehyde, and benzaldehyde; amine compounds such as hexamethylenediamine, triethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethyltetramine, isophoronediamine, amino resins, and polyamides; and metal chelate compounds such as acetylacetone and acetoacetate coordination compounds of various metals including aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium. Among these, polyisocyanate compounds are preferred due to their reactivity with polyester (A).

[0278] These crosslinking agents (D) can be used alone or in combination of two or more. However, the crosslinking agents (D) do not include the hydrolysis inhibitors (E) described later.

[0279] There are no particular limitations on the aforementioned polyisocyanate compounds. Examples include aromatic, aliphatic, and alicyclic polyisocyanates, among which toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, hydrogenated phenylmethylene diisocyanate, phenylmethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylphenylmethylene diisocyanate, and so on. Phlorone diisocyanate, norbornene diisocyanate, 1,3-bis(isocyanoxymethyl)cyclohexane, phenyl diisocyanate, lysine diisocyanate, lysine triisocyanate, naphthalene diisocyanate, and other polyisocyanates, or trimers or polymers of these polyisocyanates, biuret-type polyisocyanates, or reaction products of these polyisocyanates with polyols, etc., wherein, from the viewpoint of excellent reactivity, toluene diisocyanate, phenyl diisocyanate, and hexamethylene diisocyanate are preferred. One of them or a combination of two or more can be used.

[0280] When using a crosslinking agent (D), its content can be appropriately selected according to the amount of functional groups contained in the polyester (A), the molecular weight of the polyester (A), and the purpose of controlling the adhesive force after irradiation by active energy rays. Generally, it is preferred to be 5 parts by mass or less relative to 100 parts by mass of polyester (A), more preferably 3 parts by mass or less, further preferably 2 parts by mass or less, especially preferably 1 part by mass or less, particularly preferably 0.5 parts by mass or less, and most preferably 0 parts by mass.

[0281] If the content of this crosslinking agent (D) is too high, the polyester (A) in the hot melt coating will react with the crosslinking agent (D), the melt viscosity will increase, and there is a tendency for the pot life to become insufficient or for the coating appearance to be damaged due to gelation.

[0282] <Hydrolysis Inhibitor (E)>

[0283] In this composition, from the viewpoint of improving the hydrolysis resistance and damp heat resistance of the polyester (A), it is preferable to contain a hydrolysis inhibitor (E). The hydrolysis inhibitor (E) is not particularly limited and can be a conventionally known compound, such as a compound that reacts with and bonds to the carboxyl terminus of the aforementioned polyester (A). Specifically, compounds having functional groups such as carbodiimide or oxazoline can be included. Among these, compounds containing a carbodiimide group are preferred from the viewpoint of excellent reactivity with the carboxyl group.

[0284] As for the aforementioned carbodiimide-containing compounds, known carbodiimides having one or more carbodiimide groups (-N=C=N-) within the molecule are generally acceptable. Examples include monomeric carbodiimide compounds (E1) having one carbodiimide group within the molecule and polymeric carbodiimide compounds (E2) containing at least two carbodiimide groups within the molecule. Among these, monomeric carbodiimide compounds having one carbodiimide group within the molecule are preferred from the viewpoint of suppressing viscosity increase at high temperatures and exhibiting excellent heat resistance, and consequently, excellent resistance to damp heat.

[0285] Examples of the aforementioned monomeric carbodiimide compounds (E1) include dicyclohexylcarbodiimide, diisopropylcarbodiimide, diphenylcarbodiimide, bis(methylphenyl)carbodiimide, bis(methoxyphenyl)carbodiimide, bis(nitrophenyl)carbodiimide, bis(dimethylphenyl)carbodiimide, bis(diisopropylphenyl)carbodiimide, bis(di-tert-butylphenyl)carbodiimide, N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide, bis(triphenylsilyl)carbodiimide, and cyclic carbodiimides. Among them, diisopropylcarbodiimide, bis(methoxyphenyl)carbodiimide, bis(diisopropylphenyl)carbodiimide, N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide, and bis(triphenylsilyl)carbodiimide are preferred. Bis(diisopropylphenyl)carbodiimide is preferred because it exhibits excellent reactivity and compatibility with the carboxyl groups of polyester (A) and excellent resistance to damp heat. These can be used alone or in combination of two or more.

[0286] Examples of the aforementioned polymeric carbodiimide compounds (E2) include those obtained by decarbonation condensation reactions of the following diisocyanates. Examples of such diisocyanates include 4,4'-diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and tetramethylphenyldimethyl diisocyanate. These can be used alone or in combination of two or more.

[0287] When using a hydrolysis inhibitor (E), its content relative to 100 parts by weight of polyester (A) is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 4 parts by weight, further preferably 0.2 to 3 parts by weight, particularly preferably 0.3 to 2 parts by weight, especially preferably 0.4 to 1.5 parts by weight, and most preferably 0.5 to 1 part by weight. If the content of this hydrolysis inhibitor is too high, there is a tendency for reduced curing properties and adhesion due to active energy rays, or for the coating appearance to become insufficient due to poor compatibility with polyester. If the content is too low, there is a tendency for reduced hydrolysis resistance and insufficient damp heat durability.

[0288] Furthermore, the content of the aforementioned hydrolysis inhibitor (E) is preferably optimized according to the acid value of the polyester (A). The molar ratio ((ii) / (i)) of the total carboxyl groups (i) obtained from the acid value of the polyester (A) to the total amount of functional groups (ii) of the hydrolysis inhibitor (E) is preferably 0.5 ≤ (ii) / (i), more preferably 1 ≤ (ii) / (i) ≤ 1000, further preferably 1.5 ≤ (ii) / (i) ≤ 500, especially preferably 2 ≤ (ii) / (i) ≤ 250, particularly preferably 2.5 ≤ (ii) / (i) ≤ 100, and most preferably 3 ≤ (ii) / (i) ≤ 50.

[0289] If the content of (ii) is too high relative to (i), there is a tendency for the coating appearance to become insufficient due to poor compatibility with polyester (A), or for the curing properties, adhesion, cohesion, and hydrolysis resistance to decrease. If the content of (ii) is lower relative to (i), there is a tendency for the hydrolysis resistance and damp heat durability to decrease.

[0290] <Antioxidant (F)>

[0291] In this composition, an antioxidant (F) is more preferably included, considering the excellent heat resistance of the polyester (A), the excellent stability of the adhesive sheet, and the ability to suppress viscosity changes under thermal process-related conditions such as hot melt coating.

[0292] Examples of the aforementioned antioxidants (F) include phenolic antioxidants, hindered phenolic antioxidants, amine antioxidants, hindered amine antioxidants, sulfur-based antioxidants, and phosphoric acid antioxidants. Preferably, at least one of hindered phenolic antioxidants, hindered amine antioxidants, and phosphoric acid antioxidants is selected, and antioxidants (F) composed of hindered phenolic compounds are particularly preferred.

[0293] As hindered phenolic antioxidants, examples include antioxidants with hindered phenolic structures having sterically hindered groups such as tert-butyl bonded to at least one of the carbon atoms adjacent to the carbon atom on the aromatic ring bonded to the hydroxyl group of phenol.

[0294] When using antioxidant (F), its content relative to 100 parts by weight of polyester (A) is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, further preferably 0.05 to 3 parts by weight, especially preferably 0.1 to 2 parts by weight, and particularly preferably 0.3 to 1.0 parts by weight.

[0295] If this content is too low, the heat resistance tends to be insufficient; if it is too high, the curing property of active energy rays tends to be insufficient.

[0296] <Adhesive-enhancing resin (G)>

[0297] From the viewpoint of improving adhesive properties such as adhesion and tack, as well as coating suitability, this composition may also contain an adhesive-improving resin (G).

[0298] There are no particular limitations on the aforementioned adhesive-imparting resin (G), and conventionally known resins may be used. Examples of the aforementioned adhesive-imparting resin (G) include hydrocarbon resins, terpene resins, phenolic resins, rosin resins, xylene resins, epoxy resins, polyamide resins, ketone resins, and elastic resins. These may be used alone or in combination of two or more. Among these, hydrocarbon resins and terpene resins are preferred due to their excellent compatibility with polyester (A) and heat resistance; hydrocarbon resins are more preferred due to their excellent curing properties under active energy rays.

[0299] Examples of hydrocarbon resins include aliphatic hydrocarbon resins, aromatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aliphatic / aromatic petroleum resins (such as styrene-olefin copolymers), aliphatic / alicyclic petroleum resins, hydrogenated aromatic hydrocarbon resins, hydrogenated aliphatic hydrocarbon resins, coumarone resins, and coumarone-indene resins. Among these, aromatic hydrocarbon resins and hydrogenated aromatic hydrocarbon resins are preferred due to their superior viscosity and heat resistance.

[0300] Examples of terpene-based resins include terpene resins, terpene phenolic resins, and aromatic modified terpene resins. Specifically, α-pinene polymers, β-pinene polymers, dipentene polymers, and terpene-based resins modified with phenol, aromatics, hydrogenation, or hydrocarbons can be used. Furthermore, terpene phenolic resins are preferred due to their excellent compatibility and adhesion with polyester (A).

[0301] As the aforementioned phenolic resins, condensates of various phenols such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol, and resorcinol with formaldehyde can be used. Additionally, methyl phenolic resins obtained by reacting the aforementioned phenols with formaldehyde under an alkaline catalyst, phenolic varnishes obtained by reacting the aforementioned phenols with formaldehyde under an acid catalyst, and rosin-modified phenolic resins obtained by reacting unmodified or modified rosin, or their derivatives, with phenol under an acid catalyst and then thermally polymerizing.

[0302] Examples of rosin-based resins include rosin resin, polymerized rosin resin, hydrogenated rosin resin, rosin ester resin, hydrogenated rosin ester resin, rosin phenolic resin, and polymerized rosin ester. Specifically, unmodified rosins (raw rosin) such as gum rosin, wood rosin, and tall oil rosin, modified rosins obtained by hydrogenation, disproportionation, polymerization, or other chemical modifications, and their derivatives can be used.

[0303] For the purpose of resisting damp heat, the adhesive-imparting resin (G) preferably has an acid value of 30 mg KOH / g or less, particularly 15 mg KOH / g or less, more preferably 10 mg KOH / g or less, especially preferably 6 mg KOH / g or less, and most preferably 3 mg KOH / g. When multiple adhesive-imparting resins are used in combination, it is preferable that their average value is within the aforementioned range.

[0304] The softening point of the adhesive resin (G) (e.g., determined by the ring and ball method) is preferably 60–170°C, more preferably 80–160°C, even more preferably 90–150°C, and particularly preferably 100–140°C. If this softening point is within the aforementioned range, the viscosity and adhesive strength are improved, which is preferable.

[0305] In this invention, from the perspective of environmental protection, the adhesive-imparting resin (G) is preferably derived from plants. Examples of plant-derived adhesive-imparting resins include terpene resins and rosin resins.

[0306] When using the adhesive-improving resin (G), its content relative to 100 parts by weight of the aforementioned polyester (A) is preferably 50 parts by weight or less, more preferably 0.1 to 30 parts by weight, even more preferably 1 to 20 parts by weight, particularly preferably 2 to 15 parts by weight, and especially preferably 3 to 10 parts by weight. If the content is within the aforementioned range, it is preferable to improve the tack and adhesive strength. If the content is too high, the glass transition temperature of the adhesive layer tends to increase, the tack and adhesive strength become insufficient, or the curability of the active energy ray decreases.

[0307] <Active Energy Ray Curing Composition>

[0308] In this composition, in addition to the aforementioned polyester (A), compound with photoreactive groups (B), compound containing unsaturated groups (C), crosslinking agent (D), hydrolysis inhibitor (E), antioxidant (F), and adhesive-improving resin (G), other additives such as catalysts, plasticizers, ultraviolet absorbers, antistatic agents, silane coupling agents, fluxes, flame retardants, dispersants, emulsifiers, defoamers, leveling agents, and ion traps, as well as other inorganic or organic fillers, metal powders, pigments, and other powders or granules, may be added as other components, without impairing the effects of the present invention. Furthermore, a small amount of impurities contained in the raw materials used to manufacture the adhesive components may also be included. These may be used alone or in combination of two or more.

[0309] When this composition contains these other components, their content is preferably 70% by mass or less of the total composition, more preferably 0.001 to 50% by mass, particularly preferably 0.005 to 30% by mass, and even more preferably 0.01 to 10% by mass.

[0310] Such a composition can be obtained, for example, by preparing the aforementioned polyester (A) and any necessary components, mixing and heating it to melt and disperse it during the manufacturing of polyester (A), or mixing it in a solution of polyester (A) dissolved in an organic solvent and dispersing it using a mixing roller or the like.

[0311] The melt viscosity (at 160°C) of this composition 1 is preferably 200 Pa·s or less, more preferably 1 to 150 Pa·s, further preferably 2 to 100 Pa·s, particularly preferably 3 to 80 Pa·s, especially preferably 4 to 60 Pa·s, and most preferably 5 to 40 Pa·s. If the melt viscosity is too low, the coating appearance may show orange peel texture, resulting in poor coating suitability, or insufficient heat resistance, holding power, adhesion, and damp heat durability. If the melt viscosity is too high, the coating appearance may show streaks, resulting in insufficient coating suitability.

[0312] Furthermore, the melt viscosity (at 130°C) of this composition 2 is preferably 500 Pa·s or less, more preferably 1 to 400 Pa·s, even more preferably 3 to 300 Pa·s, particularly preferably 5 to 200 Pa·s, especially preferably 10 to 150 Pa·s, and most preferably 15 to 100 Pa·s. If the melt viscosity is too low, the coating appearance will show an orange peel texture, resulting in poor coating suitability, or insufficient heat resistance, holding power, adhesion, and damp heat durability. If the melt viscosity is too high, the coating appearance will show streaks, resulting in insufficient coating suitability.

[0313] Furthermore, from the viewpoint of thermal stability and coating suitability, this composition preferably exhibits a small change in melt viscosity before and after a heat resistance test (temperature 200°C, 3 hours, under air conditions). The change in melt viscosity is preferably 20–500%, more preferably 30–400%, further preferably 40–300%, particularly preferably 50–250%, especially preferably 60–200%, and most preferably 70–150%. If the change in melt viscosity before and after the thermal process is outside the aforementioned range, there is a tendency for the adhesive to gel or decompose, resulting in insufficient coating suitability, or insufficient adhesion and bonding strength.

[0314] In addition, the aforementioned melt viscosity change rate (%) is calculated by the following formula.

[0315] Melt viscosity change rate (%) = [(melt viscosity after heat resistance test) / (melt viscosity before heat resistance test)] × 100

[0316] This composition exhibits active energy radiation curing properties even without unsaturated groups, thus demonstrating excellent heat resistance. Furthermore, when used as an adhesive composition, it forms an adhesive with excellent adhesion and holding power. In particular, this composition is useful as a solvent-free active energy radiation curing adhesive composition for use in adhesive tapes for electronic components, adhesive tapes for labels, and the like.

[0317] [solvent]

[0318] This composition is preferably used as a solvent-free active energy ray curable adhesive composition; however, solvents may also be mixed in order to appropriately adjust the viscosity of the composition and facilitate the operation when forming a coating film.

[0319] Examples of solvents include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate; ethers such as ethylene glycol monomethyl ether; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; alcohols such as methanol and ethanol; alkanes such as hexane and cyclohexane; and aromatics such as toluene and xylene. Among these, ketone solvents and ester solvents are preferred from the perspective of controlling VOC emissions, especially methyl ethyl ketone, cyclohexanone, and ethyl acetate. Methyl ethyl ketone and ethyl acetate are preferred due to their low boiling points and excellent drying efficiency.

[0320] The solvents listed above may be used in single-use or in combination or ratio of two or more.

[0321] The content of the aforementioned solvent is preferably less than 10% by mass relative to the composition (including the solvent), more preferably 5% by mass or less, even more preferably 3% by mass or less, and particularly preferably 1% by mass or less. Furthermore, the lower limit is 0% by mass, and solvent-free is preferred. If the solvent content is too high, the amount of energy required for solvent evaporation in the coating process increases, and the effect of reducing environmental impact tends to become insufficient.

[0322] <Active Energy Ray Curing Composition>

[0323] An embodiment of the present invention provides an active energy ray curable composition comprising a polyester (A) having structural units derived from a polycarboxylic acid (α) and structural units derived from a polyol (β), wherein the polyester (A) further comprises a polyester (A1) having photoreactive groups derived from structural units of a compound (B) having photoreactive groups.

[0324] As the aforementioned polyester (A1), the same substance described in the aforementioned polyester (A) may be used.

[0325] In addition, the active energy ray curable composition of one embodiment of the present invention comprises a polyester (A) having structural units derived from polycarboxylic acids (α) and structural units derived from polyols (β), and comprises a compound (B) having photoreactive groups, wherein the content of the compound (C) containing unsaturated groups is less than 15 parts by mass relative to 100 parts by mass of polyester (A).

[0326] The aforementioned polyester (A) may be the same as that described in the aforementioned polyester (A), and a polyester (A2) that does not contain photoreactive groups is particularly preferred.

[0327] In addition, the aforementioned active energy ray curable composition may also contain compounds (B) with photoreactive groups, compounds (C) containing unsaturated groups, crosslinking agents (D), hydrolysis inhibitors (E), antioxidants (F), adhesive resins (G), additives, etc., as described in this composition, with preferred physical properties and contents.

[0328] <Adhesive>

[0329] An adhesive according to one embodiment of the present invention can be obtained by curing (crosslinking) the present composition or the aforementioned active energy ray curable composition, and an adhesive that exhibits excellent heat resistance, adhesion and holding power can be obtained.

[0330] In this invention, "crosslinking" refers to intentionally crosslinking the composition using heat and / or light, more preferably using photocrosslinking, and especially preferably using active energy rays such as ultraviolet light or electron beams. The degree of crosslinking can be controlled according to the desired physical properties and intended use.

[0331] The degree of crosslinking can be determined by the gel fraction of the adhesive. Preferably, the gel fraction is 1-100%, more preferably 3-90%, further preferably 5-80%, especially preferably 10-70%, particularly preferably 15-60%, most preferably 20-50%, and particularly preferably 25-45%. If the gel fraction is too low, the heat resistance, holding power, adhesion, and damp heat durability tend to be insufficient; if it is too high, the tack and adhesion tend to be insufficient.

[0332] Furthermore, the aforementioned gel fraction is a benchmark for the degree of crosslinking, calculated, for example, using the following method: An adhesive sheet (without a release liner) formed by forming an adhesive layer on a polymer sheet (e.g., PET film) serving as the substrate is wrapped with a 200-mesh SUS metal mesh and immersed in toluene or ethyl acetate at 23°C for 24 hours. The mass percentage of the undissolved adhesive component remaining in the metal mesh after immersion, relative to the mass of the adhesive component before immersion, is calculated and defined as the gel fraction. The mass of the substrate is deducted beforehand.

[0333] Alternatively, an adhesive sheet can be obtained by forming the aforementioned adhesive into a sheet-like adhesive layer.

[0334] This adhesive layer is preferably formed on one or both sides of the supporting substrate.

[0335] In addition, in this invention, the term "sheet" is used to include the meanings of "film" and "belt".

[0336] <Adhesive Sheet>

[0337] Adhesive sheets can be made, for example, as follows.

[0338] As a method for manufacturing the aforementioned adhesive sheet, it can be manufactured according to a known conventional method for manufacturing adhesive sheets, such as: coating the composition onto a substrate and drying it, attaching a release sheet to the composition layer on the opposite side, and curing it as needed, thereby obtaining an adhesive sheet having an adhesive layer on the substrate.

[0339] Alternatively, an adhesive sheet can be obtained by coating the composition onto a release sheet and drying it, then bonding the substrate to the composition layer on the opposite side and curing it as needed.

[0340] In addition, by forming an adhesive layer on the release sheet and attaching the release sheet to the adhesive layer on the opposite side, a substrate-free double-sided adhesive sheet can be manufactured.

[0341] For the obtained adhesive sheet and substrate-free two-sided adhesive sheet, when using it, the aforementioned release sheet is peeled off from the adhesive layer and the adhesive layer is bonded to the substrate.

[0342] Examples of substrates selected from the aforementioned materials include polyester resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, polybutylene succinate, polylactic acid, polyethylene glycol terephthalate / isophthalate copolymer, polybutylene adipate / terephthalate copolymer, hydroxybutyrate / hydroxyhexanoate copolymer, and polycaprolactone; polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; polyfluorinated vinylidene resins such as polyvinylidene fluoride, polyvinylidene fluoride, and polyfluorinated vinylidene fluoride; polyamides such as nylon 6 and nylon 6,6; polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymer, and ethylene-vinyl acetate copolymer. Vinyl polymers such as ethylene-vinyl alcohol copolymers, polyvinyl alcohol, and vinylon; cellulose resins such as cellulose triacetate and celluloid; acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, and polybutyl acrylate; fluorinated resins; polystyrene; polycarbonate; acrylonitrile-butadiene-styrene copolymers; acrylonitrile-styrene-acrylate copolymers; polyarylates; polyimides; cyclic olefin polymers; urethane acrylate resins; sheets made of at least one synthetic resin from the group consisting of polyester; aluminum, copper, and iron foils; high-quality paper, cellophane, and other papers; fabrics and nonwovens made of glass fiber, natural fiber, and synthetic fiber. These substrates can be used in single-layer or multilayer forms consisting of two or more layers.

[0343] Among these, substrates made of polyester, nonwoven fabric, or polyolefin resins are particularly preferred.

[0344] Alternatively, foam substrates can be used as the aforementioned substrate, such as foam sheets formed from foams of synthetic resins such as polyurethane foam, polyethylene foam, and polyacrylate foam. Among these, polyurethane foam and polyethylene foam are preferred from the viewpoints of excellent heat resistance, conformability to the adherend, and uniformity of adhesive strength.

[0345] The thickness of the aforementioned substrate is preferably 1 to 1000 μm, particularly preferably 3 to 500 μm, even more preferably 5 to 250 μm, and especially preferably 10 to 100 μm.

[0346] As the aforementioned release sheet, for example, a release treatment can be used for sheets, paper, cloth, non-woven fabrics, etc., made of various synthetic resins exemplified by the aforementioned substrate. Silicone-based release sheets are preferred.

[0347] As a coating method for the aforementioned composition, for example, a gravure roller coater, a reverse roller coater, a roller coating machine, an dip-coating roller coater, a bar coater, a doctor blade coater, a spray coater, or a comma coater can be used.

[0348] As for drying conditions, the drying temperature is preferably 60–140°C, more preferably 80–120°C, and the drying time is preferably 0.5–30 minutes, more preferably 1–5 minutes.

[0349] The thickness of the adhesive layer in the aforementioned adhesive sheet and substrate-free double-sided adhesive sheet is preferably 1 to 500 μm, particularly preferably 3 to 200 μm, further preferably 5 to 100 μm, and especially preferably 10 to 50 μm. If the thickness of this adhesive layer is too thin, there is a tendency for the adhesive strength to decrease; if it is too thick, there is a tendency for the uniformity of the coating to decrease, the appearance to become poor, air bubbles to be mixed into the coating, and the optical properties to become insufficient.

[0350] In addition, the thickness of the aforementioned adhesive layer can be determined by subtracting the measured thickness of the constituent components other than the adhesive layer from the measured thickness of the overall adhesive sheet using the MITSUTOYO "ID-C112B".

[0351] Additionally, a release tab can be provided on the outside of the adhesive layer for protection, as needed. Furthermore, in adhesive sheets where the adhesive layer is formed on one side of the substrate, the adhesive layer can be protected by applying a peeling treatment to the side opposite to the adhesive layer on the substrate.

[0352] Example

[0353] The following examples illustrate the invention in more detail; however, the invention is not limited to these examples as long as it does not depart from its spirit. Additionally, in the examples, "parts" and "%" refer to mass.

[0354] Glass transition temperature (°C), acid value (mgKOH / g), hydroxyl value (mgKOH / g), epoxy group concentration (mmol / g), ester bond concentration (mmol / g), unsaturated group concentration (mmol / g), heat of fusion (J / g), number average molecular weight (Mn), weight average molecular weight (Mw), peak molecular weight (Mp), polydispersity, melt viscosity (Pa·s), and biomass fraction were determined according to the description in this specification.

[0355] <Manufacturing of Polyester (A)>

[0356] The composition shown in Table 1 below is the final composition ratio (resin composition ratio), which is the relative ratio (molar ratio) of the constituent monomers of the obtained polyester and their mass.

[0357] [Manufacturing of Polyester (A1-1)]

[0358] In a reaction vessel equipped with a thermometer, stirrer, distillation column, and nitrogen inlet pipe, 51.9 parts of isophthalic acid (IPA), 592.1 parts of sebacic acid (SebA), 4.2 parts of 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) as polycarboxylic acids (α), 80.8 parts of ethylene glycol (EG), 67.0 parts of neopentyl glycol (NPG) as polyols (β), and 0.1 parts of tetrabutyl titanate as a catalyst were added. The temperature was increased over 2.5 hours until the internal temperature reached 260°C, and the esterification reaction was carried out at 260°C for 1.5 hours.

[0359] Then, 0.1 parts of tetrabutyl titanate as a catalyst were added, the system was depressurized to 2.5 hPa, and the polymerization reaction was carried out for 2 hours to obtain polyester (A1-1).

[0360] [Manufacturing of Polyester (A1-2, A1-3, A2-1)]

[0361] The resin composition was changed as shown in Table 1 below, and otherwise the same process as A1-1 was carried out to obtain polyesters (A1-2, A1-3, A2-1).

[0362] [Manufacturing of Polyester (A2-2)]

[0363] In a reaction vessel equipped with a thermometer, stirrer, distillation column, and nitrogen inlet pipe, 96.1 parts of isophthalic acid (IPA) and 467.8 parts of sebacic acid (SebA) were added as polycarboxylic acids (α), 130.3 parts of 1,4-butanediol (1,4BG) and 271 parts of neopentyl glycol (NPG) and 29.7 parts of 1,6-hexanediol (1,6HG) and 5 parts of trimethylolpropane (TMP) were added as polyols (β), and 0.1 parts of tetrabutyl titanate was added as a catalyst. The temperature was increased over 2.5 hours until the internal temperature reached 260°C, and the esterification reaction was carried out at 260°C for 1.5 hours.

[0364] Then, 0.1 parts of tetrabutyl titanate as a catalyst were added, the system was depressurized to 2.5 hPa, and the polymerization reaction was carried out for 2 hours to obtain polyester (A2-2).

[0365] [Manufacturing of Polyester (A2-3, A2-4)]

[0366] The resin composition was changed as described in Table 2 below, and otherwise the same as in A2-2 was performed to obtain polyesters (A2-3, A2-4).

[0367] The resin composition (derived from the structural units of the components) of the obtained polyester (A) is shown in Tables 1 and 3, and the physical properties are shown in Tables 2 and 4. Additionally, the abbreviations in Tables 1 and 3 are as follows.

[0368] [Polycarboxylic acid(α)]

[0369] [Aliphatic polycarboxylic acids (α1)]

[0370] • SebA: Sebacic acid (biomass source)

[0371] •AdA: Adipic acid

[0372] •SuA: Succinic acid (biomass source)

[0373] [Aromatic polycarboxylic acids (α2)]

[0374] •IPA: Isophthalic acid

[0375] ·BTDA: 3,3',4,4'-benzophenone tetracarboxylic dianhydride

[0376] In addition, the aforementioned BTDA is also a compound with a hydrogen-abstracting photoreactive group (b1).

[0377] [Polyol (β)]

[0378] [Linear aliphatic polyols (β1-1)]

[0379] •EG: Ethylene glycol (biomass source)

[0380] • 1,3PG: 1,3-Propanediol (biomass source)

[0381] ·1,4BG: 1,4-Butanediol (biomass source)

[0382] ·1,6HG: 1,6-Hexanediol

[0383] [Branched fatty acid polyols (β1-2) in which at least one side chain has a hydrocarbon group]

[0384] • NPG: Neopentyl glycol

[0385] TMP: Trimethylolpropane

[0386] [Table 1]

[0387]

[0388] [Table 2]

[0389]

[0390] [Table 3]

[0391]

[0392] [Table 4]

[0393]

[0394] <Compounds with photoreactive groups (B)>

[0395] Prepare the following as a compound (B) [photopolymerization initiator] with photoreactive groups.

[0396] ·b1-1(1): Benzophenone (manufactured by IGM Rejins, benzophenone is a hydrogen abstraction type photopolymerization initiator "Omnirad BP Flake")

[0397] ·b1-1(2): 4-Methylbenzophenone (manufactured by IGM Rejins, benzophenone is a hydrogen-extraction photopolymerization initiator "Omnirad 4MBZ Flakes")

[0398] <Hydrolysis Inhibitor (E)>

[0399] Prepare the following as hydrolysis inhibitors.

[0400] E-1: Bis(diisopropylphenyl)carbodiimide (manufactured by Rhein Chemie, monomeric carbodiimide compound "Stabaxol IPowder")

[0401] <Antioxidant (F)>

[0402] Prepare the following as antioxidants.

[0403] • F-1: Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF Japan, hindered phenolic antioxidant "Irganox 1010")

[0404] <Adhesive-enhancing resin (G)>

[0405] Prepare the following as adhesive resins.

[0406] • G-1: Aromatic hydrocarbon resin (softening point 100℃, manufactured by Mitsui Chemicals Co., Ltd., "FTR8100")

[0407] • G-2: Terpene phenolic resin (softening point 100℃, manufactured by YASUHARA CHEMICAL, "YS POLYSTAR T100")

[0408] <Example 1>

[0409] 100 parts of the aforementioned polyester (A1-1) were mixed with 1 part of hydrolysis inhibitor (E-1) and 0.1 parts of antioxidant (F-1) and stirred at 130°C for 1 hour to obtain an active energy radiation curable composition.

[0410] <Examples 2-8, Comparative Examples 1 and 2>

[0411] The components were mixed as shown in Table 5, and the process was otherwise the same as in Example 1 to obtain an active energy ray curable composition.

[0412] [Single-sided PET substrate adhesive sheet with release film]

[0413] The active energy radiation curable compositions of Examples 1-8 and Comparative Examples 1 and 2 obtained above were coated onto polyethylene terephthalate (PET) films (manufactured by Toray Industries, Inc., Lumirror T60, thickness 38 μm) with a thickness of approximately 25 μm, and then subjected to high-pressure mercury UV irradiation at a peak irradiation of 150 mW / cm². 2 Accumulated light intensity: 500mJ or 2000mJ of ultraviolet light is applied to form an adhesive layer. Then, a PET film (release film) (manufactured by Mitsui Chemicals Tosel Co., Ltd., SP-PET-01-BU, thickness 38μm) that has undergone a release treatment is pasted onto this adhesive layer to protect its surface, thereby obtaining a PET substrate adhesive sheet with a release film on one side.

[0414] The following evaluation was performed on the obtained PET substrate adhesive sheets with a release film on one side. The evaluation results are shown in Table 5 below.

[0415] [Active Energy Ray Curing Properties (Gel Fraction)]

[0416] Cut a 4cm x 4cm piece from the PET adhesive sheet with a release film on one side obtained above, and peel off the release film. Wrap it in a 200-mesh SUS metal mesh and immerse it in toluene at 23°C for 24 hours. Measure the mass of the undissolved adhesive component remaining in the metal mesh relative to the mass of the adhesive component before immersion (after deducting the mass of the PET substrate). Calculate the mass percentage using the following formula and set it as the gel fraction (%).

[0417] Gel fraction (%)

[0418] = (Mass of undissolved adhesive component remaining in the impregnated metal mesh / Mass of adhesive component before impregnation) × 100

[0419] [Adhesion strength (peel strength) (for SUS-BA)]

[0420] Prepare a SUS-BA board as the substrate. Cut the previously obtained PET adhesive sheet with a release film on one side into 25mm × 200mm pieces at 23°C and 50% RH. Remove the release film and apply pressure to the adhesive layer side of the SUS-BA board twice using a 2kg roller. After standing for 30 minutes in the same atmosphere, measure the 180-degree peel strength (N / 25mm) using an automatic graphing instrument (Shimadzu Corporation, Autograph AG-X 50N) at a peel speed of 300mm / min.

[0421] (Evaluation Criteria)

[0422] ◎(Excellent)··· Adhesive strength of 5N / 25mm or more with no adhesive residue on the adhered surfaces

[0423] 〇 (Excellent) ... Adhesive strength of 3N / 25mm or more and less than 5N / 25mm, with no adhesive residue on the adherend.

[0424] △ (Good) ... Adhesion strength ≥ 1N / 25mm and < 3N / 25mm, with no adhesive residue on the adherend.

[0425] × (Poor) ... Adhesive strength less than 1N, or there is residual adhesive on the adherend.

[0426] [Persistence]

[0427] The aforementioned PET substrate adhesive sheet with a release film on one side was cut into 25mm × 50mm pieces at 23°C and 50% RH. The release film was then removed, and the sheet was applied to a stainless steel plate (SUS304) using a 2kg roller with double-pass pressure (applied area 25mm × 25mm). The holding force was measured using a creep testing machine (TESTER SANGYO BE-501 holding force testing machine with a constant temperature and humidity chamber) at 40°C for 24 hours under a 1kg load. The evaluation criteria are as follows.

[0428] (Evaluation Criteria)

[0429] 〇 (Excellent) ... No offset

[0430] △ (Good) ... Offset less than 1.0mm

[0431] × (Difference) ... offset greater than 1.0mm or adhesive sheet falling off

[0432] [viscosity]

[0433] The PET substrate adhesive sheet with a release film on one side obtained above was cut into 12mm×12mm pieces at 23°C and 50% RH. After removing the release film, a PROBE TACK tester (TESTER SANGYO, TE-6001) was used with a probe diameter of 5mmΦ, an insertion speed of 10mm / sec, a pull-out speed of 10mm / sec, a pressurization time of 5 seconds, and an adhesion pressure of 1000gf / cm. 2 The probe tack was measured. The evaluation criteria are as follows.

[0434] (Evaluation Criteria)

[0435] ◎(Excellent)...5N or above

[0436] 〇 (Excellent) ... 3N or more and less than 5N

[0437] ×(difference)···less than 3N

[0438] [Environmental load reduction (biomass content)]

[0439] The biomass of polyester resin (A) is calculated and evaluated using the following formula.

[0440] Biomass content (%) = [(moles of carbon from plant-derived monomers calculated based on the molar ratio of polycarboxylic acids (α) and polyols (β) in polyester (A)) / (moles of carbon from all constituent monomers in polyester (A))] × 100

[0441] (Evaluation Criteria)

[0442] ◎(Excellent) ... 70% or higher

[0443] 〇 (Good) ... 50% or more but less than 70%

[0444] △ (Good) ... 30% or more but less than 50%

[0445] × (Difference) ... less than 30%

[0446] [Thermal stability]

[0447] Heat resistance tests (temperature 200°C, 3 hours, air conditions) were conducted on the active energy ray curable compositions obtained in Examples 1-8 and Comparative Examples 1 and 2. The melt viscosity at 160°C before and after the heat resistance test was measured using a flow testing machine "CFT-500EX" (manufactured by Shimadzu Corporation). The change rate of melt viscosity was calculated using the following formula and evaluated.

[0448] Melt viscosity change rate (%) = [(melt viscosity at 160℃ after heat resistance test) / (melt viscosity at 160℃ before heat resistance test)] × 100

[0449] (Evaluation Criteria)

[0450] ◎(Excellent) ... Greater than 30% and less than 300%

[0451] 〇 (Good) ... greater than 20% and less than 30%, or greater than 300% and less than 500%

[0452] △ (Good) ... greater than 10% and less than 20%, or greater than 500% and less than 1000%.

[0453] × (Difference) ... Less than 10%, or greater than 1000%

[0454] [Table 5]

[0455]

[0456] As can be seen from the results in Table 5 above, the active energy ray curable compositions and adhesive sheets of Examples 1 to 8, despite not containing unsaturated groups, still exhibit excellent active energy ray curability, and demonstrate excellent adhesion, holding power, tackiness, environmental load reduction effect, and thermal stability.

[0457] However, the active energy ray curing properties of the active energy ray curing compositions and adhesive sheets in Comparative Examples 1 and 2 are poor and cannot meet the objectives of this invention.

[0458] <Example 9>

[0459] 100 parts of the aforementioned polyester resin (A2-2) were mixed with 5 parts of a compound (b1-1(1)) having photoreactive groups, 1 part of a hydrolysis inhibitor (E-1), and 0.1 parts of an antioxidant (F-1), and stirred at 130°C for 1 hour to obtain an active energy radiation curable composition.

[0460] (Examples 10-12, Comparative Example 3)

[0461] The components were mixed as shown in Table 6, and the process was otherwise the same as in Example 9 to obtain an active energy ray curable composition.

[0462] [Single-sided PET substrate adhesive sheet with release film]

[0463] The active energy ray curable compositions of Examples 9-12 and Comparative Example 3, obtained above, were coated onto a polyethylene terephthalate (PET) film (Toray Industries, Inc., Lumirror T60, 38 μm thick) with a thickness of approximately 25 μm. A release film (Mitsui Chemicals Tocel Co., Ltd., SP-PET-01-BU, 38 μm thick) was then adhered to this adhesive layer for surface protection. The film was then irradiated with a high-pressure mercury UV irradiation device at a peak irradiance of 150 mW / cm². 2 Cumulative light intensity: 3000mJ of ultraviolet light is used to obtain a PET substrate adhesive sheet with a release film on one side.

[0464] The following evaluation was performed on the obtained PET substrate adhesive sheets with a release film on one side. The evaluation results are shown in Table 6 below.

[0465] [Gel score]

[0466] Cut a 4cm x 4cm piece from the PET adhesive sheet with a release film on one side obtained above, and peel off the release film. Wrap it in a 200-mesh SUS metal mesh and immerse it in toluene at 23°C for 24 hours. Measure the mass of the undissolved adhesive component remaining in the metal mesh relative to the mass of the adhesive component before immersion (after deducting the mass of the PET substrate). Calculate the mass percentage using the following formula, defined as the gel fraction (%).

[0467] Gel fraction (%)

[0468] = (Mass of undissolved adhesive component remaining in the impregnated metal mesh / Mass of adhesive component before impregnation) × 100

[0469] [Adhesion strength (peel strength) (for SUS-BA)]

[0470] Prepare a SUS-BA board as the substrate. Cut the previously obtained PET adhesive sheet with a release film on one side into 25mm × 200mm pieces at 23°C and 50% RH. Remove the release film and apply pressure to the adhesive layer side of the SUS-BA board twice using a 2kg roller. After standing for 30 minutes in the same atmosphere, measure the 180-degree peel strength (N / 25mm) using an automatic graphing instrument (Shimadzu Corporation, Autograph AG-X 50N) at a peel speed of 300mm / min, and evaluate it according to the following evaluation criteria.

[0471] (Evaluation Criteria)

[0472] ◎(Excellent)··· Adhesive strength of 5N / 25mm or more with no adhesive residue on the adhered surfaces

[0473] 〇 (Fair) ... Adhesive strength of 3N / 25mm or more and less than 5N / 25mm, with no adhesive residue on the adherend.

[0474] △ (Good) ... Adhesion strength ≥ 1N / 25mm and < 3N / 25mm, with no adhesive residue on the adherend.

[0475] × (Poor) ... Adhesive strength less than 1N, or there is residual adhesive on the adherend.

[0476] [Persistence]

[0477] The aforementioned PET substrate adhesive sheet with a release film on one side was cut into 25mm × 50mm pieces at 23°C and 50% RH. The release film was then removed, and the sheet was applied to a stainless steel plate (SUS304) using a 2kg roller with double-pass pressure (applied area 25mm × 25mm). The holding force was measured using a creep testing machine (TESTER SANGYO BE-501 holding force testing machine with a constant temperature and humidity chamber) at 40°C for 24 hours under a 1kg load. The evaluation criteria are as follows.

[0478] (Evaluation Criteria)

[0479] 〇 (Excellent) ... No offset

[0480] △ (Good) ... Offset less than 1.0mm

[0481] × (Difference) ... Offset greater than 1.0mm or adhesive sheet detached

[0482] [Thermal stability]

[0483] A heat resistance test was conducted using the aforementioned PET substrate adhesive sheet with a release film on one side without UV irradiation (temperature 200°C, 3 hours, air conditions). The melt viscosity at 130°C before and after the heat resistance test was measured using a flow tester "CFT-500EX" (manufactured by Shimadzu Corporation). The change rate of melt viscosity was calculated using the following formula and evaluated.

[0484] Melt viscosity change rate (%) = [(melt viscosity at 130℃ after heat resistance test) / (melt viscosity at 130℃ before heat resistance test)] × 100

[0485] (Evaluation Criteria)

[0486] ◎(Excellent) ... Greater than 30% and less than 300%

[0487] 〇 (Good) ... greater than 20% and less than 30%, or greater than 300% and less than 500%

[0488] △ (Good) ... greater than 10% and less than 20%, or greater than 500% and less than 1000%.

[0489] × (Difference) ... Less than 10%, or greater than 1000%

[0490] [Table 6]

[0491]

[0492] As can be seen from the results in Table 6 above, the active energy ray curable compositions and adhesive sheets of Examples 9 to 12, despite not containing unsaturated groups, still exhibit excellent active energy ray curability, as well as excellent adhesion, holding power, and thermal stability.

[0493] However, the active energy ray curable composition and adhesive sheet of Comparative Example 3 have poor active energy ray curing properties, adhesion, and holding power, and do not meet the purpose of the present invention.

[0494] The foregoing embodiments illustrate specific aspects of the present invention, but are merely illustrative and not intended to be limiting. Various modifications that will be apparent to those skilled in the art are intended to be covered within the scope of the present invention.

[0495] Industrial availability

[0496] Although this composition does not contain unsaturated groups, it possesses active energy radiation curing properties, thus forming an adhesive with excellent thermal stability, adhesion, and holding power. This composition is particularly useful as a solvent-free adhesive for applications such as adhesive tapes for electronic components and labels.

Claims

1. An active energy radiation-curable composition comprising polyester A having structural units derived from polycarboxylic acid α and structural units derived from polyol β, The polyester A further comprises polyester A1, which has structural units derived from compound B having photoreactive groups.

2. A radioactive energy-curable composition comprising a polyester A having structural units derived from polycarboxylic acid α and polyol β, and a compound B having photoreactive groups. The content of compound C containing polymerizable unsaturated groups in the active energy ray curable composition is less than 15 parts by mass relative to polyester A100.

3. The active energy radiation curable composition according to claim 1, further comprising polyester A2, wherein the polyester A2 has structural units derived from polycarboxylic acid α and structural units derived from polyol β, but does not have structural units derived from compound B having photoreactive groups.

4. The active energy ray curable composition according to claim 1, wherein, The compound B having a photoreactive group is compound b1 having a hydrogen-abstracting photoreactive group and / or compound b2 having a cleavage-type photoreactive group.

5. The active energy radiation curable composition according to claim 1 or 4, wherein, The structural unit derived from compound B, which has photoreactive groups, is formed by embedding ester bonds into the main chain of polyester A1.

6. The active energy radiation curable composition according to claim 1, wherein, The compound B with the photoreactive group is a polycarboxylic acid α.

7. The active energy ray curable composition according to claim 2, wherein, Compound B, which has a photoreactive group, is a hydrogen-abstracting photopolymerization initiator.

8. The active energy radiation curable composition according to claim 2, wherein, Compound B, which has photoreactive groups, does not have carboxyl or hydroxyl groups as functional groups.

9. The active energy radiation curable composition according to claim 1 or 2, wherein, The glass transition temperature of the polyester A is -80 to 30°C.

10. The active energy ray curable composition according to claim 1 or 2, wherein, The weight-average molecular weight of the polyester A is 5,000 to 500,000.

11. The active energy ray curable composition according to claim 1 or 2, wherein, The concentration of unsaturated groups in the polyester A is below 1 mmol / g.

12. The active energy radiation curable composition according to claim 1 or 2, wherein the change rate of its melt viscosity before and after heating at 200°C for 3 hours is 20-500%.

13. The active energy radiation curable composition according to claim 1 or claim 2, wherein, The organic solvent content of the active energy ray curable composition is less than 10% by mass.

14. An adhesive, which is a cured product of the active energy ray curable composition according to claim 1 or 2.

15. The adhesive according to claim 14, wherein, The adhesive has a gel fraction of 1% to 100%.

16. An adhesive sheet comprising the adhesive of claim 14.

Images