Polyester resin composition, pressure-sensitive adhesive composition, pressure-sensitive adhesive, pressure-sensitive adhesive sheet, and double-sided pressure-sensitive adhesive sheet

Abstract

To provide a polyester-based resin composition which uses a raw material derived from an environmentally friendly plant, has good pressure-sensitive adhesive physical properties to various adherends, and is excellent in pressure-sensitive adhesive physical properties such as a pressure-sensitive adhesive force and a holding force.SOLUTION: A polyester-based resin composition is provided, containing a polyester-based resin (A), wherein the polyester-based resin (A) contains a structural unit derived from at least one compound (a1) of aliphatic and / or alicyclic polyvalent carboxylic acids having 10 or more carbon atoms, and aliphatic and / or alicyclic polyol having 10 or more carbon atoms, and further contains a structural unit derived from polyvalent carboxylic acids (a2) having a furan skeleton, and a ratio (X1 / X2) of mol concentration (X1) of the structural unit derived from the compound (a1) to mol concentration (X2) of the structural unit derived from the polyvalent carboxylic acids (a2) in the polyester-based resin (A) is 0.6 or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyester resin composition containing a structural unit derived from a polyvalent carboxylic acid having a furan skeleton, and when used as an adhesive, a polyester resin composition excellent in adhesive physical properties such as adhesive force and holding force, an adhesive composition containing the same, an adhesive, an adhesive sheet, and a double-sided adhesive sheet.

Background Art

[0002] In recent years, from the viewpoints of miniaturization and weight reduction of products, adhesives have been used for joining parts and the like. As such an adhesive, instead of acrylic resins that are generally used, adhesives using polyester resins excellent in adhesive force have been studied.

[0003] On the other hand, recently, as part of measures to address the depletion of fossil resources and global warming, the use of plant-derived raw materials, which are renewable resources, has been recommended, and adhesives with a high biomass content using plant-derived raw materials that are friendly to the global environment are in demand. Among them, adhesives using polyvalent carboxylic acids having a furan skeleton as aromatic plant-derived compounds have attracted attention.

[0004] As a polyester resin using such a polyvalent carboxylic acid having a furan skeleton, for example, in Patent Document 1, a copolymerized polyester resin containing 10 mol% or more of a furandicarboxylic acid component as a dicarboxylic acid component and containing 25 mol% or more of one or more selected from the group consisting of linear aliphatic dicarboxylic acids having 5 to 12 carbon atoms and linear aliphatic glycols having 5 to 12 carbon atoms has been proposed. Further, in the same document, a copolymerized polyester resin containing 80 mol% or more of a furandicarboxylic acid component, 30 mol% or more of an aliphatic glycol having 4 to 9 carbon atoms having a side chain, and containing 25 mol% or less of one or more selected from the group consisting of linear aliphatic dicarboxylic acids having 5 to 12 carbon atoms and linear aliphatic glycols having 5 to 12 carbon atoms has also been proposed. These copolyester resins are useful as copolyester resins that exhibit excellent solvent solubility and adhesiveness, and as adhesives using the same. In Patent Document 2, an aqueous polyester dispersion containing a polyester obtained by copolymerizing 25 to 100 mol% of 2,5-furandicarboxylic acid, 0 mol% to 75 mol% of an aliphatic dicarboxylic acid having 4 to 36 carbon atoms, and 1 mol% to 10 mol% of a sulfonate group-containing compound has been proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the disclosed technology of Patent Document 1 increases the adhesiveness as an adhesive by containing furandicarboxylic acid above a certain level and setting the glass transition temperature near room temperature, but there is a problem that the tacky physical properties are insufficient when used as an adhesive. Also, the disclosed technology of Patent Document 2 above also increases the water dispersibility by containing furandicarboxylic acid above a certain level and containing a sulfonate group-containing compound, and is not a suitable composition as an adhesive.

[0007] Therefore, in the present invention, under such circumstances, even when using polyvalent carboxylic acids having a furan skeleton, a polyester-based resin composition having good tacky physical properties with respect to various adherends and excellent tacky physical properties such as adhesive strength and holding power, an adhesive composition containing the same, an adhesive, a pressure-sensitive adhesive sheet, and a double-sided pressure-sensitive adhesive sheet are provided.

Means for Solving the Problems

[0008] However, the present inventor has found that in a polyester resin composition, as polycarboxylic acids and polyols constituting the polyester resin, at least one compound selected from aliphatic and / or alicyclic polycarboxylic acids having 10 or more carbon atoms, and aliphatic and / or alicyclic polyols having 10 or more carbon atoms, and polycarboxylic acids having a furan skeleton are included, and by setting the amount of the aliphatic and / or alicyclic polycarboxylic acids having 10 or more carbon atoms and at least one compound selected from aliphatic and / or alicyclic polyols having 10 or more carbon atoms in the polyester resin to 0.6 or more in terms of molar concentration ratio with respect to the amount of the polycarboxylic acids having a furan skeleton, an adhesive that is environmentally friendly, has good adhesive physical properties to various adherends, and is excellent in adhesive strength and holding power can be obtained, and the present invention has been completed.

[0009] That is, the present invention has the following aspects [1] to

[14] . [1] A polyester resin composition containing a polyester resin (A), wherein the polyester resin (A) contains structural units derived from at least one compound (a1) selected from aliphatic and / or alicyclic polycarboxylic acids having 10 or more carbon atoms, and aliphatic and / or alicyclic polyols having 10 or more carbon atoms, and further contains structural units derived from polycarboxylic acids (a2) having a furan skeleton, and in the polyester resin (A), a polyester resin composition in which the ratio (X1 / X2) of the molar concentration (X1) of the structural units derived from the compound (a1) to the molar concentration (X2) of the structural units derived from the polycarboxylic acids (a2) is 0.6 or more. [2] The polyester resin composition according to [1], wherein the compound (a1) is a plant-derived raw material. [3] The polyester resin composition according to [1] or [2], wherein the compound (a1) is dimer acids and / or dimer diols. [4] The polyester resin composition according to any one of [1] to [3], wherein the polycarboxylic acids (a2) are 2,5-furandicarboxylic acids. [5] The polyester resin composition according to any one of [1] to [4], wherein the number average molecular weight of the above polyester resin (A) is 3000 or more. [6] The polyester resin composition according to any one of [1] to [5], wherein the weight average molecular weight of the above polyester resin (A) is 10000 or more. [7] The polyester resin composition according to any one of [1] to [6], wherein the glass transition temperature of the above polyester resin (A) is -10°C or lower. [8] The polyester resin composition according to any one of [1] to [7], wherein the biomass degree of the above polyester resin (A) is 50% or more. [9] The polyester resin composition according to any one of [1] to [8], further containing a polyvalent isocyanate compound (B).

[10] The polyester resin composition according to any one of [1] to [9], further containing a hydrolysis inhibitor (C).

[11] An adhesive composition containing the polyester resin composition according to any one of [1] to

[10] .

[12] An adhesive obtained by crosslinking the adhesive composition described in

[11] .

[13] An adhesive sheet having an adhesive layer containing the adhesive described in

[12] .

[14] A double-sided adhesive sheet having an adhesive layer containing the adhesive described in

[12] .

Advantages of the Invention

[0010] The polyester resin composition of the present invention is a polyester resin composition with a high biomass degree and friendly to the global environment, and has excellent effects on adhesive strength and holding power when used as an adhesive. Therefore, it can be effectively used for single-sided or double-sided adhesive sheets used for bonding optical members, single-sided or double-sided adhesive sheets for fixing members of portable electronic devices, and fixing electronic components.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the configuration of the present invention will be described in detail, which shows an example of a desirable embodiment. In the present invention, the term "carboxylic acids" includes carboxylic acid derivatives such as carboxylates, carboxylic anhydrides, carboxylic acid halides, and carboxylic acid esters in addition to carboxylic acids. In the present invention, "α and / or β (α and β are arbitrary configurations or components)" means three combinations: only α, only β, and α and β.

[0012] A polyester resin composition which is an embodiment of the present invention (hereinafter referred to as "this polyester resin composition") contains structural units derived from at least one compound (a1) of aliphatic and / or alicyclic polycarboxylic acids having 10 or more carbon atoms and aliphatic and / or alicyclic polyols having 10 or more carbon atoms (hereinafter referred to as "compound (a1)"), and structural units derived from polycarboxylic acids (a2) having a furan skeleton, and the ratio (X1 / X2) of the molar concentration (X1) of the structural units derived from the compound (a1) to the molar concentration (X2) of the structural units derived from the polycarboxylic acids (a2) in the above polyester resin (A) is 0.6 or more. The polyester resin (A) will be described in detail below.

[0013] <Polyester resin (A)> A polyester resin has, as its resin structure, structural units derived from polycarboxylic acids and structural units derived from polyols, and is usually obtained by polymerizing polymerization components including polycarboxylic acids and polyols.

[0014] The polyester resin (A) used in this polyester resin composition contains structural units derived from the compound (a1) and structural units derived from polycarboxylic acids (a2) having a furan skeleton. Such a polyester resin (A) is obtained by polymerizing a polymerization component including the compound (a1) and polycarboxylic acids (a2) having a furan skeleton.

[0015] [Compound (a1)] As described above, compound (a1) is an aliphatic and / or alicyclic polycarboxylic acid having 10 or more carbon atoms and / or an aliphatic and / or alicyclic polyol having 10 or more carbon atoms. Hereinafter, compound (a1) will be specifically described.

[0016] [Aliphatic and / or alicyclic polycarboxylic acids having 10 or more carbon atoms] Examples of the aliphatic and / or alicyclic polycarboxylic acids having 10 or more carbon atoms include sebacic acids, undecanedioic acids, dodecanedioic acids, brassilic acids, dimer acids, and the like. Among them, sebacic acids or dimer acids are preferable in terms of being plant-derived raw materials and easy availability and adhesive physical properties, and dimer acids are more preferable.

[0017] The above dimer acids are mainly composed of dimers of unsaturated fatty acids having an average carbon number of 10 to 26, preferably dimers of unsaturated fatty acids having an average carbon number of 12 to 24, and more preferably dimers of unsaturated fatty acids having an average carbon number of 14 to 22. Specifically, for example, they are dicarboxylic acids derived from unsaturated fatty acids such as oleic acids, linoleic acids, linolenic acids, and erucic acids. These may be used alone or in combination of two or more. Here, the "main component" refers to a component whose content is 90% by weight or more, preferably 95% by weight or more, and more preferably 98% by weight or more of the whole.

[0018] Examples of the above dimer acids include dimer acids (main carbon numbers 36 and 44) derived from the above unsaturated fatty acids, hydrogenated products of the above dimer acids, and the like. Among them, hydrogenated products of dimer acids are preferable in terms of being easy to prevent crystallization.

[0019] As raw materials for the above dimer acids, plants, beef tallow, etc. are usually used. In the present invention, dimer acids derived from any raw material can be used, but it is preferable to use raw materials derived from plants that are friendly to the global environment. By using raw materials derived from plants, the biomass content of the polyester resin (A) described later can be increased.

[0020] When using the aliphatic and / or alicyclic polycarboxylic acids having 10 or more carbon atoms as a copolymer component of the polyester resin (A), the content is preferably 10 to 100 mol% based on the total amount of polycarboxylic acids, particularly preferably 20 to 99 mol%, more preferably 35 to 90 mol%, and especially preferably 51 to 80 mol%. If such a content is too small, the polyester resin (A) tends to become too hard and the adhesive strength decreases. In addition, if such a content is too large, it tends to become too soft and the adhesive properties slightly decrease.

[0021] [Aliphatic and / or alicyclic polyol having 10 or more carbon atoms] Examples of the aliphatic and / or alicyclic polyol having 10 or more carbon atoms include 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, dimer diol, etc. These may be used alone or in combination of two or more. Among them, it is preferably 1,10-decanediol or dimer diol which is a raw material derived from plants and is easily available, and more preferably dimer diol.

[0022] The above dimer diol is generally a diol derived from the above dimer acids. In the present invention, the above dimer diol is preferably a raw material derived from plants, like the dimer acids.

[0023] When using the aliphatic and / or alicyclic polyol having 10 or more carbon atoms as a copolymer component of the polyester resin (A), the content is preferably 10 to 100 mol%, particularly preferably 20 to 99 mol%, more preferably 35 to 90 mol%, and especially preferably 51 to 80 mol% based on the total polyol. If such content is too small, the adhesion properties tend to deteriorate. In addition, if such content is too large, it becomes too soft and the adhesion properties tend to deteriorate slightly.

[0024] [Polycarboxylic acids (a2) having a furan skeleton] As the polycarboxylic acids (a2) having a furan skeleton, any polycarboxylic acid in which the furan skeleton is contained in the structure of the compound may be used. For example, 2,5-furandicarboxylic acids and the like can be mentioned. These may be used alone or in combination of two or more.

[0025] In addition to the above compound (a1) and polycarboxylic acids (a2) having a furan skeleton, the polyester resin (A) used in the present invention may use an aliphatic compound (a3) or an aromatic compound (a4) having 9 or less carbon atoms as a copolymer component.

[0026] [Aliphatic compound (a3) having 9 or less carbon atoms] Examples of the aliphatic compound (a3) having 9 or less carbon atoms include aliphatic polycarboxylic acids having 9 or less carbon atoms and aliphatic polyols having 9 or less carbon atoms.

[0027] (Aliphatic polycarboxylic acids having 9 or less carbon atoms) Examples of the aliphatic polycarboxylic acids having 9 or less carbon atoms include divalent aliphatic dicarboxylic acids and polycarboxylic acids having trivalent or more. Examples of the aliphatic dicarboxylic acids include linear alkyl dicarboxylic acids such as malonic acids, dimethylmalonic acids, succinic acids, glutaric acids, adipic acids, trimethyladipic acids, pimelic acids, 2,2-dimethylglutaric acids, azelaic acids, etc., and acyclic aliphatic dicarboxylic acids such as fumaric acids, maleic acids, itaconic acids, thiodipropionic acids, diglycolic acids; Examples of alicyclic dicarboxylic acids include alicyclic dicarboxylic acids such as 1,3 - cyclopentanedicarboxylic acids, 1,2 - cyclohexanedicarboxylic acids, 1,3 - cyclohexanedicarboxylic acids, and 1,4 - cyclohexanedicarboxylic acids. These aliphatic polycarboxylic acids having 9 or fewer carbon atoms may be used alone or in combination of two or more.

[0028] In addition, in order to increase the biomass content, it is preferable to use plant - derived aliphatic polycarboxylic acids as the aliphatic polycarboxylic acids having 9 or fewer carbon atoms. Examples of the plant - derived aliphatic polycarboxylic acids include succinic acids derived from corn.

[0029] (Aliphatic polyol having 9 or fewer carbon atoms) Examples of the aliphatic polyol having 9 or fewer carbon atoms include divalent aliphatic diols and trivalent or higher aliphatic polyalcohols. Examples of the divalent aliphatic diol include acyclic aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3 - propanediol, 2 - methyl - 1,3 - propanediol, 2,2 - dimethyl - 1,3 - propanediol (neopentyl glycol), 2 - ethyl - 2 - butyl - 1,3 - propanediol, 2 - ethyl - 2 - isobutyl - 1,3 - propanediol, 1,3 - butanediol, 1,4 - butanediol, 1,5 - pentanediol, 1,6 - hexanediol, 3 - methyl - 1,5 - pentanediol, 2,2,4 - trimethyl - 1,6 - hexanediol; alicyclic diols such as 1,2 - cyclohexanedimethanol, 1,3 - cyclohexanedimethanol, 1,4 - cyclohexanedimethanol, isosorbide, 2,2,4,4 - tetramethyl - 1,3 - cyclobutanediol. Examples of the above trivalent or higher aliphatic polyhydric alcohols include pentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,2,4 - butanetriol, 1,2,5 - pentanetriol, 1,3,6 - hexanetriol, and the like. These aliphatic polyols having 9 or fewer carbon atoms may be used alone or in combination of two or more.

[0030] Among these, from the viewpoint of lowering the glass transition temperature (Tg) of the polyester resin (A) and improving the initial adhesive strength, it is preferable to include an acyclic aliphatic diol having 9 or fewer carbon atoms in the polyol. More preferably, it is an acyclic aliphatic diol having 2 to 9 carbon atoms, and particularly preferably, it is ethylene glycol, diethylene glycol, 1,3 - propanediol, 1,4 - butanediol, 1,5 - pentanediol, 1,6 - hexanediol. Among them, ethylene glycol is particularly preferable in that it can lower the glass transition temperature (Tg) of the polyester resin (A) and the adhesiveness becomes more excellent.

[0031] The content of the acyclic aliphatic diol having 9 or fewer carbon atoms is preferably 10 to 100 mol% with respect to the total polyol, more preferably 20 to 99 mol%, still more preferably 30 to 95 mol%, and particularly preferably 40 to 90 mol%. If such content is too small, it tends to be difficult to obtain stable resin formation.

[0032] In order to increase the biomass content, it is preferable to use a plant - derived polyol as the above aliphatic polyol having 9 or fewer carbon atoms. Examples of the above plant - derived polyols include isosorbide, fatty acid ester - based diols derived from castor oil, bio - ethylene glycol, bio - 1,3 - propanediol, bio - butylene glycol, and the like. Among them, bio - ethylene glycol is preferable.

[0033] In addition, as the acyclic aliphatic diol having 9 or less carbon atoms, polyethylene terephthalate may be used. The polyethylene terephthalate is a polyester resin obtained by polymerizing terephthalic acids and ethylene glycol. Therefore, by using polyethylene terephthalate, the polyester resin (A) has a structural unit derived from ethylene glycol of polyethylene terephthalate as a structural unit derived from an acyclic aliphatic diol having 9 or less carbon atoms. Further, the polyethylene terephthalate may be a virgin product or a recycled product, but it is preferable to use a recycled product from the viewpoint of the global environment.

[0034] Furthermore, from the viewpoint of forming a reaction point with the polyvalent isocyanate compound (B) described later in the polyester resin (A) and increasing the cohesive force, it is preferable to use an aliphatic polyol having 9 or less carbon atoms and having three or more hydroxyl groups, for example, trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,2,6-hexanetriol can be used. Among these, it is particularly preferable to use trimethylolpropane because gels are less likely to occur.

[0035] The content of such an aliphatic polyol having three or more hydroxyl groups is preferably 20 mol% or less, more preferably 0.1 to 10 mol%, and particularly preferably 0.5 to 5 mol% with respect to the total polyol. If the content of such an aliphatic polyol having three or more hydroxyl groups is too high, the production of the polyester resin (A) tends to be difficult.

[0036] In addition, it is preferable to use an aliphatic polyol having 9 or less carbon atoms that is derived from plants. However, when the biomass degree of polycarboxylic acids is high, an aliphatic polyol not derived from plants may be used from the viewpoint of ease of polycondensation. However, even in such a case, in order to increase the biomass degree, it is preferable to use an acyclic aliphatic diol having a linear structure and 4 or less carbon atoms, and particularly preferably an acyclic aliphatic diol having a linear structure and 2 to 3 carbon atoms. Examples of the acyclic aliphatic diol having a linear structure and 4 or less carbon atoms include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and the like. That is, when an aliphatic polyol having 9 or less carbon atoms and a small number of 4 or less carbon atoms is used, the weight ratio of carboxylic acids having a high biomass degree as the polyester resin (A) increases, and the biomass degree can be increased.

[0037] [Aromatic compound (a4)] Examples of the aromatic compound (a4) include aromatic polycarboxylic acids and aromatic polyols. These may be used alone or in combination of two or more. Among them, from the viewpoint of excellent adhesive strength and holding power, it is preferable to use aromatic polycarboxylic acids as the aromatic compound (a4).

[0038] (Aromatic polycarboxylic acids) Examples of the aromatic polycarboxylic acids include divalent aromatic dicarboxylic acids and trivalent or higher aromatic polycarboxylic acids, and aromatic dicarboxylic acids are preferably used from the viewpoint of stably obtaining a polyester resin.

[0039] Examples of the aromatic dicarboxylic acids include benzene-based aromatic dicarboxylic acids such as phthalic acids, terephthalic acids, isophthalic acids, benzylmalonic acids, diphenic acids, 4,4'-oxydibenzoic acids, naphthalenedicarboxylic acids such as 1,8-naphthalenedicarboxylic acids, 2,3-naphthalenedicarboxylic acids, 2,7-naphthalenedicarboxylic acids; and heterocyclic dicarboxylic acids such as thiophenedicarboxylic acids (pyrrole, pyrazole, imidazole, pyridine, pyridazine, pyrimidine, pyrazine, etc.). These may be used alone or in combination of two or more. Among them, terephthalic acids and isophthalic acids are preferred because of their easy availability.

[0040] Examples of the aromatic polycarboxylic acids having a valency of three or more include trimellitic acids, pyromellitic acids, trimesic acids, etc. These may be used alone or in combination of two or more.

[0041] It is also preferable to use polyethylene terephthalate as the aromatic polycarboxylic acid. As described above, polyethylene terephthalate is a polyester resin obtained by polymerizing terephthalic acids and ethylene glycol. By using the polyethylene terephthalate, the polyester resin (A) will have a structural unit derived from terephthalic acids of polyethylene terephthalate as a structural unit derived from aromatic polycarboxylic acids. The polyethylene terephthalate may, if necessary, be modified with substances such as isophthalic acids, phthalic anhydrides, adipic acids, cyclohexanedicarboxylic acids, sebacic acids, 1,3-butanediol, 1,4-butanediol, cyclohexanedimethanol. Also, the polyethylene terephthalate may be a virgin product or a recycled product, but it is preferable to use a recycled product from the viewpoint of the global environment.

[0042] (Aromatic polyol) Examples of the aromatic polyol include divalent aromatic diols. Examples of the above-mentioned divalent aromatic diols include bisphenol A, 4,4'-thiodiphenol, 4,4'-methylenediphenol, 4,4'-dihydroxybiphenyl, o-, m-, and p-dihydroxybenzene, 2,5-naphthalenediol, p-xylenediol, and their ethylene oxide adducts, propylene oxide adducts, etc. These may be used alone or in combination of two or more.

[0043] [Production of Polyester Resin (A)] In the present invention, the polyester resin (A) can be produced by subjecting polycarboxylic acids and polyols to a polycondensation reaction in the presence of a catalyst by a known method. In the polycondensation reaction, first, an esterification reaction or a transesterification reaction is carried out, and then the polycondensation reaction is carried out. When it is not necessary to obtain a high molecular weight, it may be produced only by an esterification reaction or a transesterification reaction.

[0044] In such an esterification reaction or transesterification reaction, a catalyst is used. Specifically, for example, titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate, antimony-based catalysts such as antimony trioxide, germanium-based catalysts such as germanium dioxide, and catalysts such as zinc acetate, manganese acetate, and dibutyltin oxide can be mentioned. One or more of these are used. Among these, antimony trioxide, tetrabutyl titanate, germanium dioxide, and zinc acetate are preferable in view of the balance between high catalytic activity and the hue of the resulting reaction product.

[0045] The compounding amount of the above-mentioned catalyst is preferably 1 to 10,000 ppm based on the total copolymerization components (by weight), particularly preferably 10 to 5,000 ppm, and more preferably 20 to 3,000 ppm. If the compounding amount is too small, the polymerization reaction tends not to proceed sufficiently. If it is too large, there is no advantage such as shortening of the reaction time, and side reactions tend to occur easily.

[0046] Regarding the reaction temperature during the esterification reaction, 200 to 300 °C is preferred, particularly preferably 210 to 280 °C, and even more preferably 220 to 260 °C. If such a reaction temperature is too low, the reaction tends not to proceed sufficiently, and if it is too high, side reactions such as decomposition tend to occur easily. Also, the pressure during the reaction is usually normal pressure.

[0047] As the reaction conditions for the polycondensation reaction carried out after the above esterification reaction or transesterification reaction, the same catalyst as used in the above esterification reaction or transesterification reaction is further blended in approximately the same amount, and the reaction temperature is preferably 200 to 280 °C, particularly preferably 210 to 270 °C, and it is preferable to gradually reduce the pressure of the reaction system and finally react at 5 hPa or less. If such a reaction temperature is too low, the reaction tends not to proceed sufficiently, and if it is too high, side reactions such as decomposition tend to occur easily.

[0048] Thus, a polyester resin (A) containing a structural unit derived from the compound (a1) and a structural unit derived from the polyvalent carboxylic acid (a2) having a furan skeleton is obtained.

[0049] In the above polyester resin (A), from the viewpoint of excellent adhesive strength and holding power, the ratio (X1 / X2) of the molar concentration (X1) of the structural unit derived from the compound (a1) to the molar concentration (X2) of the structural unit derived from the polyvalent carboxylic acids (a2) having a furan skeleton in the above polyester resin (A) needs to be 0.6 or more. Preferably it is 1.0 or more, more preferably 1.5 or more, even more preferably 2.0 or more, particularly preferably 2.5 or more. If (X1 / X2) is less than the above numerical value, the adhesive strength and holding power decrease. Also, the upper limit value of (X1 / X2) is usually 20, preferably 10, more preferably 6.0, even more preferably 5.0, particularly preferably 4.0, and especially preferably 3.5.

[0050] The number average molecular weight of the above polyester resin (A) is preferably 3,000 or more, more preferably 3,500 to 50,000, still more preferably 4,000 to 40,000, particularly preferably 5,000 to 30,000, especially preferably 6,000 to 20,000, and most preferably 7,000 to 15,000. If the number average molecular weight is too large, the handleability decreases, so a large amount of solvent is required, and the environmental load tends to increase. If the number average molecular weight is too small, the adhesive physical properties tend to decrease.

[0051] The weight average molecular weight of the above polyester resin (A) is preferably 10,000 or more, more preferably 10,000 to 500,000, still more preferably 20,000 to 300,000, particularly preferably 30,000 to 250,000, especially preferably 40,000 to 200,000, and most preferably 50,000 to 150,000. If the weight average molecular weight is too small, the adhesive physical properties tend to decrease. If the weight average molecular weight is too large, the handleability decreases, so a large amount of solvent is required, and the environmental load tends to increase.

[0052] The above number average molecular weight and weight average molecular weight are the number average molecular weight and weight average molecular weight in terms of standard polystyrene molecular weight, and are measured by using two columns of TSKgel SuperMultipore HZ-M (exclusion limit molecular weight: 2×10 6 , theoretical plate number: 16,000 plates / book, filler material: styrene-divinylbenzene copolymer, filler particle size: 4 μm) in series on a high performance liquid chromatograph (manufactured by Tosoh Corporation, "HLC-8320GPC").

[0053] In addition, the biomass content of the above polyester resin (A) is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, especially preferably 85% or more, and most preferably 90% or more. The upper limit is 100%. If such a biomass content is low, the reduction of the environmental load tends to be insufficient.

[0054] Here, the biomass content of the above polyester resin (A) refers to the weight ratio of the part of the plant-derived raw material used in the production of the polyester resin (A) incorporated into the resin with respect to the total weight of the polyester resin (A), and the calculation method is as follows. Regarding the biomass content of polycarboxylic acids and polyols, it shall be determined from the weighted average of their respective biomass contents. Also, among the following calculation methods, it is sufficient if the value obtained by any of the methods is within the above range.

[0055] (Calculation method) <When accompanied by a polycondensation reaction> Biomass content (%) = [(number of moles of carbon of plant-derived monomers calculated from the molar ratio of polycarboxylic acids and polyols in the polyester resin (A)) / (number of moles of carbon of all constituent monomers in the polyester resin (A))] × 100

[0056] <When not accompanied by a polycondensation reaction> Biomass content (%) = [(number of moles of carbon of plant-derived monomers in the polyester resin (A)) / (number of moles of carbon of all constituent monomers in the polyester resin (A))] × 100

[0057] Also, the above biomass content can also be determined by analyzing the composition ratio by NMR and calculating the number of carbon atoms of the plant-derived monomers / the total number of carbon atoms.

[0058] Furthermore, the above biomass content can also be measured by the method described in "Discrimination Technology of the Origin of Biofuels Using Natural Radioactive Carbon C-14", Research Report No. 4, 2009, Tokyo Metropolitan Institute of Industrial Technology.

[0059] As a method for adjusting the above biomass content to a predetermined range, using plant-derived polycarboxylic acids or plant-derived polyols as the main component can be mentioned, but in terms of being able to efficiently increase the biomass content, it is particularly preferable that the polycarboxylic acids are plant-derived.

[0060] The glass transition temperature (Tg) of the above polyester resin (A) is preferably -10 °C or lower, more preferably -90 to -10 °C, particularly preferably -60 to -20 °C, still more preferably -50 to -30 °C, and especially preferably -45 to -35 °C. If the glass transition temperature (Tg) is too high, the adhesion when used as an adhesive tends to decrease, and if it is too low, the heat resistance and cohesive force tend to decrease.

[0061] The above glass transition temperature (Tg) is measured using a differential scanning calorimeter DSC Q20 manufactured by TA Instruments. The measurement temperature range is -90 to 100 °C, and the temperature increase rate is 10 °C / min.

[0062] The ester group concentration of the polyester resin (A) is usually 2 mmol / g or more, preferably 3 to 10 mmol / g, still more preferably 3.6 to 6 mmol / g, and particularly preferably 4.2 to 5 mmol / g. If such an ester group concentration is too small, the polyester resin (A) becomes soft, and if it is too soft, the adhesive properties tend to decrease.

[0063] The above ester group concentration (mmol / g) refers to the number of moles of ester bonds in 1 g of the polyester resin (A), and is obtained, for example, as a calculated value from the charged amounts. Such a calculation method is the value obtained by dividing the smaller number of moles of the charged amounts of carboxylic acids and polyols by the total weight, and an example of the calculation formula is shown below. In the case where the charged amounts of polycarboxylic acids and polyols are the same in molar amount, either of the following calculation formulas may be used. Also, when using a monomer having both a carboxy group and a hydroxyl group, or when producing a polyester from caprolactone, etc., the calculation method will be changed appropriately.

[0064] <When polycarboxylic acids are in a small amount> Ester group concentration (mmol / g) = [((X1 / x1 × m1 + X2 / x2 × m2 + X3 / x3 × m3 ···) / Z) × 1000] X1, X2, X3 ···: Charging amount (g) of polycarboxylic acids x1, x2, x3 ···: Molecular weight of polycarboxylic acids m1, m2, m3 ···: Number of carboxy groups per molecule of polycarboxylic acids Z: Final weight (g) <When there is little polyol> Ester group concentration (mmol / g) = [((Y1 / y1 × n1 + Y2 / y2 × n2 + Y3 / y3 × n3 ···) / Z)] × 1000 Y1, Y2, Y3 ···: Charging amount (g) of polyols y1, y2, y3 ···: Molecular weight of polyols n1, n2, n3 ···: Number of hydroxyl groups per molecule of polyols Z: Final weight (g)

[0065] Also, the above ester group concentration can also be measured by a known method using NMR or the like. For example, the ester group concentration of the polyester resin (A) is measured by 1 1H-NMR measurement (proton nuclear magnetic resonance spectroscopy) with a resonance frequency of 400 MHz, 13 13C-NMR measurement (carbon nuclear magnetic resonance spectroscopy).

[0066] Examples of the method for adjusting the above ester group concentration include, for example, a method of selecting a polyol having 4 or less carbon atoms as the polyol, a method of increasing the content of linear carboxylic acids as the polycarboxylic acids, and a method of combining both of them.

[0067] The heat of crystal melting measured by a differential scanning calorimeter of the polyester resin (A) is usually 10 J / g or less, preferably 5 J / g or less, more preferably 2 J / g or less, and particularly preferably no heat of crystal melting. If such heat of crystal melting is too large, crystallinity will appear, and the storage stability of the resin solution will tend to decrease, or the stability and adhesive properties at low temperatures when made into an adhesive sheet will tend to decrease. The above-mentioned heat of crystal melting refers to the energy consumed when a crystallized substance is heated and melted, and can be measured by a differential scanning calorimeter (DSC).

[0068] As a method for adjusting the above-mentioned heat of crystal melting, for example, a method of appropriately using polyvalent carboxylic acids having an alkyl group in the side chain or polyols having an alkyl group in the side chain, a method of using three or more copolymer monomer components, preferably four or more components, etc. can be mentioned.

[0069] The acid value of the above-mentioned polyester resin (A) is preferably 10 mgKOH / g or less, more preferably 5 mgKOH / g or less, and particularly preferably 2 mgKOH / g or less in terms of preventing hydrolysis and improving durability. If such an acid value is too large, the durability tends to decrease. To adjust the above-mentioned acid value, for example, the ratio of polyol is increased or the reaction conditions are adjusted during the esterification reaction or transesterification reaction. The lower limit value of the acid value is usually 0 mgKOH / g.

[0070] The acid value of the above-mentioned polyester resin (A) is determined by neutralization titration based on JIS K0070. In addition, the acid value in the present invention means the content of carboxy groups in the polyester resin (A). The above-mentioned carboxy groups include those in the carboxylate ion state in which the carboxy group is neutralized by a basic compound.

[0071] In the present polyester resin composition, the content of the polyester resin (A) is usually 70% by weight or more, preferably 80% by weight or more, and particularly preferably 90% by weight or more from the viewpoint of adhesive physical properties.

[0072] In the present polyester resin composition, together with the above-mentioned polyester resin (A), it is preferable to contain a polyvalent isocyanate compound (B), a hydrolysis inhibitor (C), and, if necessary, a tackifier (D), a urethanization catalyst (E), an antioxidant (F), etc.

[0073] <Polyvalent isocyanate compound (B)> It is preferable that this polyester resin composition further contains a polyvalent isocyanate compound (B) as a crosslinking agent. By containing the polyvalent isocyanate compound (B), the polyester resin (A) is crosslinked with the polyvalent isocyanate compound (B) to have excellent cohesive strength, and the performance as an adhesive can be improved.

[0074] Examples of such polyvalent isocyanate compounds (B) include aromatic isocyanate crosslinking agents such as tolylene diisocyanate crosslinking agents such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, xylylene diisocyanate crosslinking agents such as 1,3-xylylene diisocyanate, diphenylmethane crosslinking agents such as diphenylmethane-4,4-diisocyanate, and naphthalene diisocyanate crosslinking agents such as 1,5-naphthalene diisocyanate; alicyclic isocyanate crosslinking agents such as isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, 1,3-diisocyanatomethylcyclohexane, and norbornane diisocyanate; aliphatic isocyanate crosslinking agents such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; and adducts of the above isocyanate compounds and polyol compounds such as trimethylolpropane, burette bodies of these isocyanate compounds, isocyanurate bodies, etc. In addition, the above polyvalent isocyanate compound (B) can also be used when the isocyanate moiety is blocked with phenol, lactam, etc. These polyvalent isocyanate compounds (B) may be used alone or in combination of two or more.

[0075] When using such a polyvalent isocyanate compound (B), its content can be appropriately selected according to the molecular weight and application purpose of the polyester resin (A). Usually, with respect to 1 equivalent of at least one of the hydroxyl groups and carboxyl groups contained in the polyester resin (A), the polyvalent isocyanate compound (B) is preferably contained in a ratio such that the reactive groups contained in the polyvalent isocyanate compound (B) are 0.2 to 10 equivalents, particularly preferably 0.5 to 5 equivalents, and more preferably 0.5 to 3 equivalents. If the equivalent number of the reactive groups contained in such a polyvalent isocyanate compound (B) is too small, the cohesive force tends to decrease, and if it is too large, the flexibility tends to decrease.

[0076] Also, in the reaction between the polyester resin (A) and the polyvalent isocyanate compound (B), organic solvents having no functional groups that react with these polyester resin (A) and polyvalent isocyanate compound (B) components can be used, for example, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatic compounds such as toluene and xylene. These can be used alone or in combination of two or more.

[0077] <Hydrolysis inhibitor (C)> The above hydrolysis inhibitor (C) is contained as necessary to ensure the long-term durability of the polyester resin composition. As the above hydrolysis inhibitor (C), conventionally known ones can be used. For example, compounds that react and bond with the carboxyl group terminals of the polyester resin (A) can be mentioned. Specifically, for example, compounds containing functional groups such as carbodiimide groups, epoxy groups, and oxazoline groups can be mentioned. Among these, carbodiimide group-containing compounds are preferable in that they have a high effect of eliminating the catalytic activity of protons derived from carboxyl group terminals.

[0078] As the carbodiimide group-containing compound, usually, a known carbodiimide having one or more carbodiimide groups (-N=C=N-) in the molecule may be used. However, from the viewpoint of improving durability under higher temperature and humidity conditions, a compound containing two or more carbodiimide groups in the molecule, that is, a polyvalent carbodiimide compound is preferably used. In particular, a compound containing three or more, more preferably five or more, and especially seven or more carbodiimide groups in the molecule is preferably used. The number of carbodiimide groups in the molecule is usually 50 or less. If there are too many carbodiimide groups, the molecular structure becomes too large, and the compatibility tends to decrease. It is also preferable to use a high molecular weight polycarbodiimide produced by subjecting a diisocyanate to a decarboxylation condensation reaction in the presence of a carbodiimidation catalyst.

[0079] Furthermore, it is preferable in terms of storage stability that the terminal isocyanate groups of the high molecular weight polycarbodiimide are blocked by a blocking agent. Examples of the blocking agent include compounds having active hydrogen that reacts with isocyanate groups, or compounds having isocyanate groups. For example, monoalcohols, monocarboxylic acids, monoamines, and monoisocyanates having one substituent selected from carboxy groups, amino groups, and isocyanate groups can be mentioned.

[0080] Examples of such high molecular weight polycarbodiimides include those obtained by subjecting the following diisocyanates to a decarboxylation condensation reaction.

[0081] 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-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, etc. These can be used alone or in combination of two or more. Such high molecular weight polycarbodiimide may be synthesized or a commercially available product may be used.

[0082] Examples of commercially available products of the carbodiimide group-containing compound include, for example, the Carbodilite (registered trademark) series manufactured by Nisshinbo Chemical Inc. Among them, Carbodilite (registered trademark) "V-01", "V-02B", "V-03", "V-04K", "V-04PF", "V-05", "V-07", "V-09", "V-09GB" are preferable in terms of excellent compatibility with organic solvents.

[0083] Examples of the epoxy group-containing compound include, for example, glycidyl ester compounds and glycidyl ether compounds, etc.

[0084] Specific examples of the glycidyl ester compound include, for example, glycidyl benzoate, glycidyl t-butylbenzoate, glycidyl p-toluate, glycidyl cyclohexanecarboxylate, glycidyl pelargonate, glycidyl stearate, glycidyl laurate, glycidyl palmitate, glycidyl behenate, glycidyl versatate, glycidyl oleate, glycidyl linoleate, glycidyl linolenate, glycidyl behenolate, glycidyl stearolate, diglycidyl terephthalate, diglycidyl isophthalate, diglycidyl phthalate, diglycidyl naphthalenedicarboxylate, diglycidyl methyl terephthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, diglycidyl cyclohexanedicarboxylate, diglycidyl adipate, diglycidyl succinate, diglycidyl sebacate, diglycidyl dodecanedioate, diglycidyl octadecanedicarboxylate, triglycidyl trimellitate, tetraglycidyl pyromellitate, etc. These can be used alone or in combination of two or more kinds.

[0085] Specific examples of the glycidyl ether compound include, for example, phenyl glycidyl ether, o-phenyl glycidyl ether, 1,4-bis(β,γ-epoxypropoxy)butane, 1,6-bis(β,γ-epoxypropoxy)hexane, 1,4-bis(β,γ-epoxypropoxy)benzene, 1-(β,γ-epoxypropoxy)-2-ethoxyethane, 1-(β,γ-epoxypropoxy)-2-benzyloxyethane, 2,2-bis-[p-(β,γ-epoxypropoxy)phenyl]propane and bisphenols such as 2,2-bis-(4-hydroxyphenyl)propane and 2,2-bis-(4-hydroxyphenyl)methane and bisglycidyl polyethers obtained by the reaction of epichlorohydrin, etc. These can be used alone or in combination of two or more kinds.

[0086] As the oxazoline group-containing compound, bisoxazoline compounds and the like are preferable. Specifically, for example, 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(4,4-dimethyl-2-oxazoline), 2,2'-bis(4-ethyl-2-oxazoline), 2,2'-bis(4,4'-diethyl-2-oxazoline), 2,2'-bis(4-propyl-2-oxazoline), 2,2'-bis(4-butyl-2-oxazoline), 2,2'-bis(4-hexyl-2-oxazoline), 2,2'-bis(4-phenyl-2-oxazoline), 2,2'-bis(4-cyclohexyl-2-oxazoline), 2,2'-bis(4-benzyl-2-oxazoline), 2,2'-p-phenylene bis(2-oxazoline), 2,2'-m-phenylene bis(2-oxazoline), 2,2'-o-phenylene bis(2-oxazoline), 2,2'-p-phenylene bis(4-methyl-2-oxazoline), 2,2'-p-phenylene bis(4,4-dimethyl-2-oxazoline), 2,2'-m-phenylene bis(4-methyl-2-oxazoline), 2,2'-m-phenylene bis(4,4-dimethyl-2-oxazoline), 2,2'-ethylene bis(2-oxazoline), 2,2'-tetramethylene bis(2-oxazoline), 2,2'-hexamethylene bis(2-oxazoline), 2,2'-octamethylene bis(2-oxazoline), 2,2'-decamethylene bis(2-oxazoline), 2,2'-ethylene bis(4-methyl-2-oxazoline), 2,2'-tetramethylene bis(4,4-dimethyl-2-oxazoline), 2,2'-9,9'-diphenoxyethane bis(2-oxazoline), 2,2'-cyclohexylene bis(2-oxazoline), 2,2'-diphenylene bis(2-oxazoline) and the like can be exemplified. Among these, 2,2'-bis(2-oxazoline) is most preferable from the viewpoint of reactivity with the polyester resin (A). Further, these can be used alone or in combination of two or more.

[0087] As these hydrolysis inhibitors (C), those with low volatility are preferred, and for this reason, those with a high number-average molecular weight are preferably used. Usually, the number-average molecular weight is 300 to 10,000, preferably 1,000 to 5,000. Also, as the hydrolysis inhibitor (C), those with a high weight-average molecular weight are preferably used from the viewpoint of hydrolysis resistance. The weight-average molecular weight of the hydrolysis inhibitor (C) is preferably 500 or more, more preferably 1,000 or more, still more preferably 2,000 or more, and particularly preferably 3,000 or more. The upper limit of the weight-average molecular weight is usually 50,000. If the molecular weight of the hydrolysis inhibitor (C) is too small, the hydrolysis resistance tends to decrease. In addition, if the molecular weight is too large, the compatibility with the polyester resin (A) tends to decrease.

[0088] Among these hydrolysis inhibitors (C), it is preferable to use a carbodiimide group-containing compound. In this case, the carbodiimide equivalent is preferably 50 to 10,000, particularly 100 to 1,000, and more preferably 150 to 500. The carbodiimide equivalent indicates the chemical formula weight per one carbodiimide group.

[0089] When using the above hydrolysis inhibitor (C), its content is preferably 0.01 to 10 parts by weight, particularly preferably 0.1 to 5 parts by weight, and still more preferably 0.2 to 3 parts by weight with respect to 100 parts by weight of the above polyester resin (A). If such a content is too much, turbidity tends to occur due to poor compatibility with the polyester resin (A), and if it is too little, sufficient durability tends to be difficult to obtain.

[0090] In addition, the content of the hydrolysis inhibitor (C) is preferably optimized according to the acid value of the polyester resin (A). The molar ratio [(y) / (x)] of the total number of moles of the functional groups of the hydrolysis inhibitor (C) in the polyester resin composition to the total number of moles of the acidic functional groups of the polyester resin (A) in the polyester resin composition is preferably 0.5 ≦ (y) / (x), particularly preferably 1 ≦ (y) / (x) ≦ 1000, and more preferably 1.5 ≦ (y) / (x) ≦ 100. If the molar ratio of (y) to (x) is too low, the moisture and heat resistance performance tends to deteriorate. If the molar ratio of (y) to (x) is too high, the compatibility with the polyester resin (A) tends to decrease, and the adhesive strength, cohesive strength, and durability performance tend to decrease.

[0091] <Adhesion promoter (D)> In this polyester resin composition, it is preferable to contain an adhesion promoter (D) in terms of improving the adhesion characteristics.

[0092] The adhesion promoter (D) is not particularly limited, and conventionally known ones can be used. Examples of the adhesion promoter (D) include hydrocarbon-based adhesion-promoting resins, terpene-based resins, phenolic resins, rosin-based resins, xylene resins, epoxy resins, polyamide-based resins, ketone-based resins, elastomer-based resins, etc. These may be used alone or in combination of two or more. Among them, hydrocarbon-based adhesion-promoting resins and terpene-based resins are preferable. In addition, it is particularly preferable that the adhesion promoter (D) contains at least one hydrocarbon-based adhesion-promoting resin, and the hydrocarbon-based adhesion-promoting resin is preferably 30% by weight or more, preferably 50% by weight or more, and preferably 70% by weight or more of the total adhesion promoter.

[0093] Examples of the hydrocarbon-based tackifying resin include various hydrocarbon-based resins such as aliphatic hydrocarbon resins, aromatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aliphatic-aromatic petroleum resins (such as styrene-olefin copolymers), aliphatic-alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, and coumarone-indene resins. Examples of commercially available products include "FTR6100", "FTR6110", "FTR6125", "FTR8100", "FTR8120", "FMR0150", etc. manufactured by Mitsui Chemicals, Inc.

[0094] Examples of the terpene-based resin include terpene resins, terpene phenol resins, and aromatic-modified terpene resins. Specifically, α-pinene polymers, β-pinene polymers, dipentene polymers, and terpene-based resins obtained by phenol modification, aromatic modification, hydrogenation modification, or hydrocarbon modification of these can be used. Examples of commercially available products include "YS Polyster S145", "YS Resin PX1000", "YS Resin PX1250", "YS Polyster T160", "YS Polyster T145", "YS Polyster T130", "YS Resin TO115", "YS Polyster G150", "YS Polyster G125", "YS Polyster U130", "Clearon P125", etc. manufactured by Yasuhara Chemical Co., Ltd. Terpene-based resins are preferred in terms of good adhesion to non-polar adherends such as polypropylene.

[0095] Examples of the phenolic resin include condensates of various phenols such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcinol, etc. with formaldehyde. Further, resol obtained by adding formaldehyde to the phenols under an alkaline catalyst, novolak obtained by condensing the phenols with formaldehyde under an acid catalyst, rosin-modified phenolic resins obtained by adding phenol to unmodified or modified rosin or their derivatives such as rosin under an acid catalyst and then thermally polymerizing, etc. can be used.

[0096] Examples of the above-mentioned rosin-based resins include rosin resin, polymerized rosin resin, hydrogenated rosin resin, rosin ester resin, hydrogenated rosin ester resin, rosin phenol resin, polymerized rosin ester, etc. Specifically, unmodified rosins (raw rosins) such as gum rosin, wood rosin, and tall oil rosin, modified rosins obtained by hydrogenating, disproportionating, polymerizing, or otherwise chemically modifying these, and derivatives thereof can be used. Examples of commercially available products include "Halister TF", "Halitack 8LJA", "Halitack PH", "Halitack FK100", "Halitack PCJ", etc. manufactured by Harima Kasei Co., Ltd.

[0097] The tackifier (D) preferably has an acid value of 30 mgKOH / g or less, particularly preferably 10 mgKOH / g or less, more preferably 6 mgKOH / g or less, and especially preferably 3 mgKOH / g or less. When using a plurality of types of tackifiers (D) in combination, the average is preferably within the above range.

[0098] The softening point of the tackifier (D) (measured, for example, by the ring and ball method) is preferably 80 to 170°C, particularly preferably 90 to 160°C, more preferably 100 to 155°C, still more preferably 120 to 155°C, and especially preferably 135 to 150°C. When the softening point is within the above range, the tack characteristics (adhesive force, cohesive force) can be improved, which is preferable.

[0099] In this polyester resin composition, the tackifier (D) is preferably of plant origin in order to keep the biomass degree of the entire polyester resin composition high. Examples of plant-derived tackifiers include terpene resins, rosin-based resins, etc.

[0100] The above-mentioned tackifier (D) preferably contains an aromatic structural unit from the viewpoints of improving cohesive force and compatibility. Examples of tackifiers containing an aromatic structural unit include aromatic hydrocarbon resins, aliphatic-aromatic petroleum resins (such as styrene-olefin copolymers), coumarone resins, coumarone-indene resins, terpene phenol resins, and aromatic-modified terpene resins.

[0101] When using the tackifier (D), its content is preferably 2 to 200 parts by weight, more preferably 5 to 150 parts by weight, still more preferably 8 to 100 parts by weight, particularly preferably 10 to 80 parts by weight, and most preferably 20 to 50 parts by weight, based on 100 parts by weight of the polyester resin (A). When the content is within the above range, the tack characteristics (tack force, cohesion) tend to be improved.

[0102] <Urethanization catalyst (E)> This adhesive composition more preferably contains a urethanization catalyst (E) from the viewpoint of reaction rate.

[0103] Examples of the urethanization catalyst (E) include organometallic compounds and tertiary amine compounds. These can be used alone or in combination of two or more.

[0104] Examples of the above organometallic compounds include zirconium compounds, iron compounds, tin compounds, titanium compounds, lead compounds, cobalt compounds, zinc compounds, etc.

[0105] Examples of the above zirconium compounds include zirconium naphthenate, zirconium acetylacetonate, etc. Examples of the above iron compounds include iron acetylacetonate, iron 2-ethylhexanoate, etc. Examples of the above tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dilaurate, etc. Examples of the above titanium compounds include dibutyltitanium dichloride, tetrabutyl titanate, butoxytitanium trichloride, etc. Examples of the above lead compounds include lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate, etc. Examples of the cobalt-based compound include cobalt 2-ethylhexanoate, cobalt benzoate, and the like. Examples of the zinc-based compound include zinc naphthenate, zinc 2-ethylhexanoate, and the like.

[0106] Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo-(5,4,0)-undecene-7, and the like.

[0107] Among these urethanization catalysts (E), organometallic compounds are preferred, and zirconium-based compounds are particularly preferred, in terms of reaction rate and pot life of the adhesive layer. Further, it is preferable to use acetylacetone in combination with the urethanization catalyst (E) as a catalyst action inhibitor. By including acetylacetone, it is preferable in terms of suppressing the catalytic action at low temperatures and extending the pot life.

[0108] When using the urethanization catalyst (E), its content is preferably 0.0001 to 1 part by weight, particularly preferably 0.001 to 0.1 part by weight, and even more preferably 0.01 to 0.05 part by weight, based on 100 parts by weight of the polyester resin (A). If the content is too small, the aging time until the crosslinking reaction is completed tends to be long, and if it is too large, the adhesive physical properties tend to deteriorate.

[0109] <Antioxidant (F)> It is more preferable for this polyester resin composition to contain an antioxidant (F) from the viewpoint of improving the stability of the resin.

[0110] Examples of the antioxidant (F) include hindered phenol-based antioxidants, amine-based antioxidants, sulfur-based antioxidants, phosphate-based antioxidants, and the like. These may be used alone or in combination of two or more. Among them, it is preferably at least one selected from hindered phenol-based antioxidants, amine-based antioxidants, and phosphate-based antioxidants, and particularly preferably an antioxidant composed of a hindered phenol-based compound. Examples of the hindered phenol antioxidant include antioxidants having a hindered phenol structure in which a group with a large steric hindrance such as a tertiary butyl group is bonded to at least one of the adjacent carbon atoms of the carbon atom on the aromatic ring to which the hydroxyl group of phenol is bonded.

[0111] When using the antioxidant (F), its content is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 8 parts by weight, and still more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the polyester resin (A). If such a content is too small, there is a tendency that glue residue on the adherend is likely to occur, and if it is too large, there is a tendency that the adhesive physical properties decrease.

[0112] In this polyester resin composition, in addition to the above polyester resin (A), polyvalent isocyanate compound (B), hydrolysis inhibitor (C), tackifier (D), urethanization catalyst (E), and antioxidant (F), within a range not impairing the effects of the present invention, additives such as plasticizers, ultraviolet absorbers, stabilizers, antistatic agents, etc., and other additives such as inorganic or organic fillers, powders such as metal powders and pigments, and particulate additives can be blended. Further, it may contain a small amount of impurities contained in the raw materials for producing the constituent components of the polyester-based adhesive composition. These can be used alone or in combination of two or more.

[0113] Such a polyester resin composition can be obtained, for example, by preparing the above polyester resin (A) and optional components as necessary, and blending and dispersing them during the production of the polyester resin (A), or by blending them into a solution of the polyester resin (A) dissolved in an organic solvent and dispersing them using a mixing roller.

[0114] This polyester resin composition preferably has a biomass content of 50% or more from the viewpoint of reducing environmental impact, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, especially preferably 85% or more, and most preferably 90% or more. The biomass content of the above-mentioned adhesive can be adjusted by adjusting the types and blending amounts of the polyester resin (A) and other blending components. The biomass content of the above-mentioned polyester resin composition refers to the ratio of the weight of the plant-derived raw materials used in producing the polyester resin composition to the total weight of the polyester resin composition, and can be determined, for example, by the following formula. Biomass content (%) = [(Sum of (biomass content of each plant-derived raw material used in producing the polyester resin composition) × (weight of each plant-derived raw material used in producing the polyester resin composition))] / (total weight of the polyester resin composition)

[0115] In addition, the biomass content of the above-mentioned polyester resin composition can also be measured by the method using the aforementioned NMR or the method using natural radioactive carbon C-14. Among the above calculation methods, it is sufficient that the value obtained by any method is within the above range.

[0116] The adhesive composition (hereinafter referred to as "this adhesive composition"), which is one embodiment of the present invention, contains this polyester resin composition and is preferably composed of this polyester resin composition. In addition, the adhesive (hereinafter referred to as "this adhesive"), which is one embodiment of the present invention, is formed by crosslinking the above-mentioned this adhesive composition.

[0117] And the adhesive sheet (hereinafter referred to as "this adhesive sheet"), which is one embodiment of the present invention, has an adhesive layer containing the above-mentioned this adhesive, and such an adhesive layer is preferably formed on one or both sides of a support substrate. In the present invention, "sheet" is described to include the meaning of "film" and "tape".

[0118] <Adhesive Sheet> This adhesive sheet can be produced, for example, as follows. As a method for manufacturing such an adhesive sheet, it can be manufactured according to a known general method for manufacturing an adhesive sheet. For example, the adhesive composition is applied and dried on a substrate, a release sheet is laminated on the adhesive layer surface on the opposite side, and if necessary, cured to obtain an adhesive sheet having an adhesive layer containing an adhesive on the substrate.

[0119] Also, the adhesive sheet can be obtained by applying and drying the adhesive composition on a release sheet, laminating a substrate on the adhesive layer surface on the opposite side, and if necessary, curing.

[0120] In addition, a substrate-free double-sided adhesive sheet can be manufactured by forming an adhesive layer on a release sheet and laminating a release sheet on the adhesive layer surface on the opposite side.

[0121] When in use, the obtained adhesive sheet or substrate-free double-sided adhesive sheet has the release sheet peeled off from the adhesive layer and the adhesive layer laminated to an adherend.

[0122] Examples of the base material include sheets made of at least one synthetic resin selected from the group consisting of polyester resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate / isophthalate copolymer; polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; polyfluoroethylene resins such as polyvinyl fluoride, polyvinylidene fluoride, and polyfluoroethylene; polyamides such as nylon 6 and nylon 6,6; vinyl polymers such as polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and vinylon; cellulose resins such as triacetate cellulose and cellophane; acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, and polybutyl acrylate; polystyrene; polycarbonate; polyarylate; polyimide; and cycloolefin polymer; metal foils of aluminum, copper, and iron; papers such as high-quality paper and glassine paper; and woven or non-woven fabrics made of glass fibers, natural fibers, synthetic fibers, etc. These base materials can be used as single-layer bodies or multi-layer bodies in which two or more types are laminated.

[0123] Among these, base materials made of polyethylene terephthalate and polyimide are particularly preferred, and polyethylene terephthalate is particularly preferred in terms of excellent adhesion to the adhesive.

[0124] In addition, as the base material, a foam base material, for example, a foam sheet made of a foam of a synthetic resin such as polyurethane foam, polyethylene foam, and polyacrylate foam can be used. Among these, polyethylene foam and polyacrylate foam are preferred in terms of excellent followability to the adherend and balance of adhesive strength.

[0125] The thickness of the above base material is preferably, for example, 1 to 1000 μm, particularly preferably 2 to 500 μm, and even more preferably 3 to 300 μm.

[0126] As the release sheet, for example, a sheet made of various synthetic resins exemplified by the above base material, paper, cloth, a non-woven fabric, etc. that have been subjected to a release treatment can be used. As the release sheet, it is preferable to use a silicone-based release sheet.

[0127] As the coating method of this adhesive composition, for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, etc. may be used.

[0128] As the conditions of the curing treatment, the temperature is usually room temperature (23°C) to 70°C, and the time is usually 1 to 30 days. Specifically, for example, it can be carried out under conditions such as 1 to 20 days at 23°C, preferably 3 to 14 days at 23°C, 1 to 10 days at 40°C, etc.

[0129] Also, as the drying conditions, the drying temperature is preferably 60 to 140°C, particularly preferably 80 to 120°C, and the drying time is preferably 0.5 to 30 minutes, particularly preferably 1 to 5 minutes.

[0130] The thickness of the adhesive layer of the above adhesive sheet and the substrate-less double-sided adhesive sheet is preferably 2 to 500 μm, particularly preferably 5 to 200 μm, and even more preferably 10 to 100 μm. If the thickness of such an adhesive layer is too thin, the adhesive strength tends to decrease. If it is too thick, it becomes difficult to coat uniformly, and defects such as air bubbles entering the coating film tend to occur easily. In addition, when considering impact absorbency, it is preferably 50 μm or more.

[0131] Incidentally, the thickness of the adhesive layer is obtained by subtracting the measured value of the thickness of the constituent members other than the adhesive layer from the measured value of the thickness of the entire adhesive sheet using "ID-C112B" manufactured by Mitutoyo Corporation.

[0132] Regarding the gel fraction of the pressure-sensitive adhesive layer of the above-mentioned pressure-sensitive adhesive sheet, it is preferably 10% by weight or more from the viewpoints of durability performance and adhesive strength, particularly preferably 20 to 80% by weight, and even more preferably 30 to 70% by weight. If the gel fraction is too low, the cohesive force decreases, and the holding force tends to decrease. In addition, if the gel fraction is too high, the adhesive strength tends to decrease due to the increase in the cohesive force.

[0133] The above gel fraction serves as a measure of the degree of crosslinking and is calculated, for example, by the following method. That is, a pressure-sensitive adhesive sheet (one without a release sheet) in which a pressure-sensitive adhesive layer is formed on a polymer sheet as a base material (for example, a PET film, etc.) is wrapped with a 200-mesh SUS wire mesh and immersed in toluene at 23°C for 24 hours. The weight percentage of the insoluble pressure-sensitive adhesive component remaining in the wire mesh after immersion with respect to the weight of the pressure-sensitive adhesive component before immersion is defined as the gel fraction. However, the weight of the base material is subtracted.

[0134] Furthermore, such a pressure-sensitive adhesive sheet may be provided with a release sheet on the outside of the pressure-sensitive adhesive layer and protected as needed. Also, in a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is formed on one side of the base material, by performing a peeling treatment on the surface of the base material opposite to the pressure-sensitive adhesive layer, it is also possible to protect the pressure-sensitive adhesive layer using the peeled surface.

[0135] This pressure-sensitive adhesive can be used for bonding various members, and in particular, it is used for single-sided or double-sided pressure-sensitive adhesive sheets for bonding optical members, single-sided or double-sided pressure-sensitive adhesive sheets for fixing members of portable electronic devices, and fixing electronic members, etc.

Examples

[0136] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples as long as it does not exceed the gist thereof. In the examples, "parts" and "%" indicate weight basis.

[0137] Also, regarding the measurement of the biomass content, recycled carbon usage rate, weight-average molecular weight, glass transition temperature of the polyester resin, and gel fraction of the adhesive layer, and the biomass content and recycled carbon usage rate of the polyester resin composition in the following examples, the measurements were carried out according to the aforementioned methods.

[0138] The polyester resin was produced by the following method (see Table 1).

[0139] [Examples 1 to 5, Comparative Examples 1 to 3] [Production of Polyester Resins (A) [A-1 to A-5], (A’) [A’-1 to A’-3]] Polycarboxylic acids and polyols as shown in Table 1 below were charged into a reaction vessel equipped with a thermometer, stirrer, rectification column, nitrogen inlet tube, and vacuum device. As a catalyst, tetrabutyl titanate was charged at 0.2 mmol / mol based on the polycarboxylic acids. The temperature was gradually raised to 240 to 250 °C, and an esterification reaction was carried out over 4 hours. Thereafter, the internal temperature was raised to 260 °C, tetrabutyl titanate was charged at 0.2 mmol / mol based on the polycarboxylic acids, the pressure was reduced to 1.33 to 2.66 hPa, and a polymerization reaction was carried out over 2 to 3 hours to produce the polyester resin (A) or (A’). The composition ratios, physical properties, etc. of the obtained polyester resin (A) or (A’) were as shown in Table 2 below. In the above production, the plant-derived raw materials were hydrogenated distilled dimer acid, 2,5-furandicarboxylic acid, and sebacic acid.

[0140] [Table 1]

[0141] [Table 2]

[0142] Next, prior to preparing the polyester resin composition part (adhesive composition), each component was prepared as follows.

[0143] [Polyvalent isocyanate compound (B)] · Polyvalent isocyanate compound (B-1): "Coronate L55E, solid content concentration 55%" (manufactured by Tosoh Corporation)

[0144] [Hydrolysis inhibitor (C)] · Carbodiimide compound (C-1): "Carbodilite V-09GB, solid content concentration 70%" (manufactured by Nisshinbo Chemicals, Inc.)

[0145] [Examples 1-1 to 5-1, Comparative Examples 1-1 to 3-1] Using the above polyester resin, crosslinking agent, and hydrolysis inhibitor, a polyester resin composition (adhesive composition) was prepared according to the compounding composition shown in Table 3 below, and an adhesive sheet was produced.

[0146] The polyester resin [(A) or (A')] obtained above was diluted with ethyl acetate to a solid content concentration of 50%, and polyvalent isocyanate compound (B-1) and carbodiimide compound (C-1) were blended at the compounding ratio (solid content ratio) shown in Table 3. Further, 0.02 part (solid content) of a zirconium compound (Matsumoto Fine Chemicals "Organix ZC-150") diluted with acetylacetone to a solid content concentration of 1% as a urethanization catalyst was added, and the mixture was stirred and mixed to obtain a polyester resin composition (adhesive composition). The obtained adhesive composition was applied to a polyethylene terephthalate (PET) film (thickness 38 μm) so that the thickness after drying was about 25 μm, and then dried at 100°C for 3 minutes to form an adhesive layer. Thereafter, a release-treated PET film (release film) was adhered to the adhesive layer to protect its surface, and the film was cured in an atmosphere at 40°C for 10 days to obtain an adhesive sheet.

[0147] The following evaluations were performed on the obtained adhesive sheets of the examples and comparative examples. The evaluation results are shown in Table 3 below.

[0148] [Initial adhesive strength (peel strength) (against SUS-BA)] An SUS-BA plate was prepared as the adherend. After cutting the adhesive sheet obtained above into 25 mm × 200 mm in an environment of 23°C and 50% RH, the release film was peeled off, the adhesive layer side was brought into contact with the SUS-BA plate, and a 2 kg roller was reciprocated to apply pressure for sticking. Then, after standing still for 30 minutes in the same atmosphere, using an autograph (manufactured by Shimadzu Corporation, Autograph AGS-H 500N), the 180-degree peel strength (N / 25 mm) was measured at a peel rate of 300 mm / min, and the peel state was observed visually.

[0149] <Adhesive force (peel strength) after 72 hours (against SUS)> An SUS-BA plate was prepared as the adherend. After cutting the adhesive sheet obtained above into 25 mm × 200 mm in an environment of 23°C and 50% RH, the release film was peeled off, the adhesive layer side was brought into contact with the SUS-BA plate, and a 2 kg roller was reciprocated to apply pressure for sticking. Then, after standing still for 72 hours in the same atmosphere, using an autograph (manufactured by Shimadzu Corporation, Autograph AGS-H 500N), the 180-degree peel strength (N / 25 mm) was measured at a peel rate of 300 mm / min, and the peel state was observed visually.

[0150] <Initial adhesive force (peel strength) (against PP)> A PP plate was prepared as the adherend. After cutting the adhesive sheet obtained above into 25 mm × 200 mm in an environment of 23°C and 50% RH, the release film was peeled off, the adhesive layer side was brought into contact with the PP plate, and a 2 kg roller was reciprocated to apply pressure for sticking. Then, after standing still for 30 minutes in the same atmosphere, using an autograph (manufactured by Shimadzu Corporation, Autograph AGS-H 500N), the 180-degree peel strength (N / 25 mm) was measured at a peel rate of 300 mm / min, and the peel state was observed visually.

[0151] <Retention force (cohesion force)> The adhesive sheet obtained above was pasted according to JIS Z-0237 with SUS304 as the adherend and a pasting area of 25 mm × 25 mm, and then a load of 1 kg was applied to the one that had been left standing at 80°C for 20 minutes, and the displacement after 24 hours was measured.

[0152]

Table 3

[0153] From the results in Table 3 above, the pressure-sensitive adhesive sheets of Examples 1-1 to 5-1 prepared using the polyester resin compositions (adhesive compositions) of Examples 1 to 5 were excellent in the initial and after-time adhesiveness to metal adherends, and furthermore had desired adhesiveness even to adherends difficult to adhere such as polyolefin resins, and were excellent in the balance between adhesive strength and holding power. Also, in the pressure-sensitive adhesive sheets of Comparative Examples 1-1 and 2-1 prepared using the polyester resin compositions (adhesive compositions) of Comparative Example 1 and Comparative Example 2, which do not contain structural units derived from the polyvalent carboxylic acid (a2) having a furan skeleton and have only structural units derived from the compound (a1), the adhesive strength particularly over time was low. Furthermore, in the pressure-sensitive adhesive sheet of Comparative Example 3-1 prepared using the polyester resin composition (adhesive composition) of Comparative Example 3, which contains structural units derived from the polyvalent carboxylic acid (a2) having a furan skeleton but has too few structural units derived from the compound (a1) relative to the content of structural units derived from the polyvalent carboxylic acids (a2) having a furan skeleton, the adhesive physical properties were inferior both initially and after-time to metal adherends, and did not satisfy all the effects of the present invention.

Industrial Applicability

[0154] The polyester resin composition, the adhesive composition containing the same, and the adhesive of the present invention have an excellent effect on the adhesive physical properties to various adherends such as metal even when using a polyester resin with a high biomass degree, and are used for single-sided or double-sided pressure-sensitive adhesive sheets used for bonding optical members, single-sided or double-sided pressure-sensitive adhesive sheets for fixing members of portable electronic devices, fixing electronic members, etc.

Claims

1. An adhesive composition containing a polyester resin composition containing a polyester resin (A), wherein the polyester resin (A) contains structural units derived from at least one compound (a1) selected from aliphatic and / or alicyclic polycarboxylic acids having 10 or more carbon atoms and aliphatic and / or alicyclic polyols having 10 or more carbon atoms, and further contains structural units derived from polycarboxylic acids (a2) having a furan skeleton, wherein the compound (a1) is dimer acids and / or dimer diols, and the ratio (X1 / X2) of the molar concentration (X1) of the structural units derived from the compound (a1) to the molar concentration (X2) of the structural units derived from the polycarboxylic acids (a2) in the polyester resin (A) is 0.6 or more. An adhesive composition characterized by this.

2. The adhesive composition according to claim 1, wherein the compound (a1) is a plant-derived raw material.

3. The adhesive composition according to claim 1 or 2, wherein the polycarboxylic acids (a2) are 2,5-furandicarboxylic acids.

4. The adhesive composition according to any one of claims 1 to 3, wherein the number average molecular weight of the polyester resin (A) is 3000 or more.

5. The adhesive composition according to any one of claims 1 to 4, wherein the weight average molecular weight of the polyester resin (A) is 10000 or more.

6. The adhesive composition according to any one of claims 1 to 5, wherein the glass transition temperature of the polyester resin (A) is -10°C or lower.

7. The adhesive composition according to any one of claims 1 to 6, wherein the biomass content of the polyester resin (A) is 50% or more.

8. The adhesive composition according to any one of claims 1 to 7, further containing a polyisocyanate compound (B).

9. The adhesive composition according to any one of claims 1 to 8, further containing a hydrolysis inhibitor (C).

10. An adhesive characterized in that the adhesive composition according to any one of claims 1 to 9 is crosslinked.

11. An adhesive sheet having an adhesive layer containing the adhesive according to claim 10.

12. A double-sided adhesive sheet having an adhesive layer containing the adhesive according to claim 10.

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