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 resin composition that comprises eco-friendly plant-derived raw material and has excellent adhesive properties to various adherends, the adhesive properties including adhesive power and holding power.SOLUTION: A polyester resin composition contains a polyester resin. The polyester resin is a polyester resin (A1) that contains, as a constitutional unit derived from at least one of a polycarboxylic acid (a) and a polyol (b), a constitutional unit derived from at least one compound (α1) of a C44 dimer acid and a C44 dimer diol, the content of the compound (α1)-derived constitutional units being 25 mol% or more relative to the total of the constitutional units of the polycarboxylic acid (a) and / or the polyol (b), and with a number average molecular weight of 3000 or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyester resin composition, an adhesive composition, an adhesive, an adhesive sheet, and a double-sided adhesive sheet. More specifically, the present invention relates to a polyester resin composition using a plant-derived raw material that is friendly to the global environment, and when used as an adhesive, a polyester resin composition, an adhesive composition, an adhesive, an adhesive sheet, and a double-sided adhesive sheet that are excellent in adhesive physical properties such as adhesive strength and holding power.

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 the generally used acrylic resin, an adhesive using a polyester resin having excellent adhesive strength has also 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 there is a demand for adhesives with a high biomass content that use plant-derived raw materials friendly to the global environment.

[0004] As such a polyester-based adhesive using a plant-derived raw material, in Patent Document 1, a polyester obtained by polymerizing using dimer acid as a dicarboxylic acid component and dimer diol as a diol component, and an adhesive containing a polyester in which the hydroxyl group contained in the diol component is 1.04 to 2.10 moles with respect to 1 mole of the carboxyl group contained in the dicarboxylic acid component and a tackifier has been proposed to have a small amount of organic solvent used, be capable of thick coating, and be excellent in adhesiveness, holding property, and anti-rebound property.

[0005] Furthermore, in Patent Document 2, a polyester-based adhesive has been proposed that is a polyester obtained by polymerizing using dimer acid as a dicarboxylic acid component and dimer diol as a diol component, and the polyol component is composed of glycols having an even number of carbon atoms.

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the disclosed technologies of Patent Documents 1 and 2, although dimer acids are used, only examples using dimer acids having 36 carbon atoms obtained by dimerization of unsaturated fatty acids having 18 carbon atoms such as oleic acid and linoleic acid are described, and there is no description regarding dimer acids having 44 carbon atoms obtained by dimerization of unsaturated fatty acids having 22 carbon atoms such as erucic acid.

[0008] Generally, when a polyester resin is used as an adhesive, crosslinking agents such as isocyanate compounds, epoxy compounds, and metal chelate compounds, and additives such as tackifiers are often used. However, when a polyester resin composition is prepared using plant-derived raw materials that are friendly to the global environment, such as dimer acids and dimer diols having a long alkyl chain, the adhesiveness may decrease when additives are added.

[0009] Therefore, in the present invention, under such circumstances, among plant-derived raw materials that are friendly to the global environment, when at least one of dimer acids having 44 carbon atoms and dimer diols having 44 carbon atoms obtained by dimerization of unsaturated fatty acids having 22 carbon atoms such as erucic acid is used, a polyester resin composition, an adhesive composition, an adhesive, an adhesive sheet, and a double-sided adhesive sheet having good adhesive physical properties with respect to various adherends and excellent adhesive physical properties such as adhesive strength and holding power are provided.

Means for Solving the Problems

[0010] However, the present inventors have discovered that the above problems can be solved by, in a polyester resin composition containing a polyester resin, the polyester resin contains, as the polycarboxylic acids and polyols constituting the polyester resin, structural units derived from at least one compound selected from dimer acids having 44 carbon atoms and dimer diols having 44 carbon atoms in an amount of 25 mol % or more relative to the total of structural units derived from the polycarboxylic acids and polyols, and by setting the number average molecular weight to 3,000 or more, thereby completing the present invention.

[0011] The present inventors also discovered that the above problems can be solved by including, in a pressure-sensitive adhesive composition containing a polyester-based resin, a structural unit derived from at least one compound selected from the group consisting of a dimer acid having 44 carbon atoms and a dimer diol having 44 carbon atoms as the polycarboxylic acids and polyols that constitute the polyester-based resin, and thus completed the present invention.

[0012] That is, the present invention has the following aspects [1] to

[10] . [1] A polyester-based resin composition containing a polyester-based resin, The polyester-based resin composition is a polyester-based resin (A1) having a number average molecular weight of 3,000 or more, the polyester-based resin containing structural units derived from polycarboxylic acids (a) and polyols (b), and the structural units derived from at least one of the polycarboxylic acids (a) and polyols (b) include structural units derived from at least one compound (α1) of dimer acids having 44 carbon atoms and dimer diols having 44 carbon atoms, the content of the structural units derived from at least one compound (α1) of dimer acids having 44 carbon atoms being 25 mol % or more relative to the total of the structural units derived from the polycarboxylic acids (a) and polyols (b). [2] The polyester-based resin composition according to [1], wherein the polyester-based resin (A1) has a weight-average molecular weight of 10,000 or more. [3] The polyester resin composition according to [1] or [2], wherein the biomass content of the polyester resin composition is 50% or more. [4] The polyester resin composition according to any one of [1] to [3], further containing a polyisocyanate compound (B). [5] The polyester resin composition according to any one of [1] to [4], further containing a hydrolysis inhibitor (C). [6] An adhesive composition containing a polyester resin, wherein the polyester resin contains structural units derived from polycarboxylic acids (a) and polyols (b), and as the structural units derived from at least one of the polycarboxylic acids (a) and polyols (b), it contains structural units derived from at least one compound (α1) of dimer acids having 44 carbon atoms and dimer diols having 44 carbon atoms, and is an adhesive composition comprising a polyester resin (A). [7] The adhesive composition according to [6], wherein the adhesive strength under the following conditions is 7 N / 25 mm or more. Adhesive strength: When an adhesive sheet formed of an adhesive composition is formed on a substrate, after being attached to an adherend of a polypropylene plate and allowed to stand for 30 minutes in an environment of 23°C and 50% RH, the 180-degree peel strength (N / 25 mm) at a peel rate of 300 mm / min with respect to the adherend. [8] An adhesive obtained by crosslinking the adhesive composition according to [6] or [7]. [9] An adhesive sheet having an adhesive layer containing the adhesive according to [8].

[10] A double-sided adhesive sheet having an adhesive layer containing the adhesive according to [8].

Advantages of the Invention

[0013] The polyester resin composition of the present invention is a polyester resin composition with a high biomass content and friendly to the global environment. When used as an adhesive, it has good adhesive physical properties to various adherends and excellent holding power. Therefore, the polyester resin composition of the present invention is effectively 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 members of electronic members, and the like.

[0014] In addition, the pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition with a high biomass content and friendly to the global environment. When used as a pressure-sensitive adhesive, it has good adhesive physical properties to various adherends and excellent holding power. Therefore, the pressure-sensitive adhesive composition of the present invention is effectively 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 members of electronic members, and the like.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the configuration of a polyester resin composition (hereinafter referred to as "the present polyester resin composition"), which is an embodiment of the present invention, and a pressure-sensitive adhesive composition (hereinafter referred to as "the present pressure-sensitive adhesive composition"), which is an embodiment of the present invention, will be described in detail. However, these show examples of desirable embodiments. 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.

[0016] The present polyester resin composition contains a polyester resin, and the polyester resin contains a structural unit derived from at least one compound (α1) of dimer acids having 44 carbon atoms and dimer diols having 44 carbon atoms in an amount of 25 mol% or more based on the total of the structural units derived from polycarboxylic acids (a) and polyols (b), and is a polyester resin (A1) having a number average molecular weight of 3000 or more. In addition, this adhesive composition contains a polyester resin, and the above polyester resin contains, as a structural unit derived from at least one of polycarboxylic acids (a) and polyols (b), a structural unit derived from at least one compound (α1) of dimer acids having 44 carbon atoms and dimer diols having 44 carbon atoms, and is a polyester resin (A). Hereinafter, the above polyester resin (A) will be described in detail.

[0017] <Polyester resin (A)> The polyester resin has, as its resin structure, a structural unit derived from polycarboxylic acids and a structural unit derived from polyols, and is usually obtained by polymerizing a polymerization component containing polycarboxylic acids and polyols.

[0018] The polyester resin (A1) used in this polyester resin composition contains a structural unit derived from at least one compound (α1) of dimer acids having 44 carbon atoms which are polycarboxylic acids (a) and dimer diols having 44 carbon atoms which are polyols (b) (hereinafter sometimes referred to as "compound (α1)"), the content of the structural unit derived from the above compound (α1) is 25 mol% or more based on the total of the structural units derived from polycarboxylic acids (a) and polyols (b), and the number average molecular weight is 3000 or more.

[0019] In addition, the polyester resin (A) used in this adhesive composition contains a structural unit derived from compound (α1) as a structural unit derived from at least one of polycarboxylic acids (a) and polyols (b).

[0020] [Compound (α1)] The at least one compound (α1) of the above dimer acids having 44 carbon atoms and dimer diols having 44 carbon atoms is, as described above, at least one of dimer acids having 44 carbon atoms which are polycarboxylic acids and dimer diols having 44 carbon atoms which are polyols.

[0021] [Dimer acids having 44 carbon atoms] The dimer acids having 44 carbon atoms are dicarboxylic acids having 44 carbon atoms as the main component, which are dimers of unsaturated fatty acids having an average carbon number of 22. Examples of the dimers having 22 carbon atoms as the main component include unsaturated fatty acids such as erucic acids. Here, the term "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 total.

[0022] Examples of the dimer acids having 44 carbon atoms include dimer acids derived from unsaturated fatty acids such as erucic acid, and hydrogenated products of the dimer acids. These may be used alone or in combination of two or more. Among these, hydrogenated products are preferred because they are more likely to prevent crystallization.

[0023] As the raw material for the dimer acid having 44 carbon atoms, plants, beef tallow, etc. are usually used, and in the present invention, dimer acids having 44 carbon atoms derived from any raw material can be used, but it is preferable to use a plant-derived raw material that is environmentally friendly. By using a plant-derived raw material, the biomass content of the polyester resin (A) described below can be increased.

[0024] When the above-mentioned dimer acids having 44 carbon atoms are used as copolymerization components of the polyester resin (A), the content of the dimer acids is preferably 25 to 100 mol % relative to the total polycarboxylic acids (a), particularly preferably 30 to 99 mol %, further preferably 40 to 90 mol %, and particularly preferably 50 to 80 mol %. If the content is too low, the resin tends to be too hard and the adhesive strength tends to decrease. On the other hand, if the content is too high, the resin tends to be too soft and the adhesive properties tend to decrease slightly.

[0025] [Dimer diol with 44 carbon atoms] The dimer diol having 44 carbon atoms used in the polyester resin (A) is generally a diol derived from the dimer acids having 44 carbon atoms. As with the dimer acids having 44 carbon atoms, the dimer diol having 44 carbon atoms is preferably a plant-derived raw material.

[0026] When the above-mentioned dimer diol having 44 carbon atoms is used as a copolymerization component of the polyester resin (A), the content of the dimer diol is preferably 25 to 100 mol % relative to the total polyol (b), particularly preferably 30 to 99 mol %, further preferably 40 to 80 mol %, and particularly preferably 50 to 80 mol %. If the content is too low, the adhesive properties tend to deteriorate. On the other hand, if the content is too high, the adhesive properties tend to deteriorate slightly due to excessive softening.

[0027] [Aromatic compounds] The polyester resin (A) may contain an aromatic compound as a copolymerization component. Examples of the aromatic compound include aromatic polycarboxylic acids and aromatic polyols. Among these, aromatic polycarboxylic acids are preferred as the aromatic compound because of their excellent adhesive strength and holding power.

[0028] (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 since they allow the polyester resin (A) to be stably obtained.

[0029] Examples of the above 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 furandicarboxylic acids, 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, isophthalic acids, and furandicarboxylic acids are preferred in view of easy availability.

[0030] Examples of the above trivalent or higher aromatic polycarboxylic acids include trimellitic acids, pyromellitic acids, trimesic acids, etc. These may be used alone or in combination of two or more.

[0031] Also, it is preferable to use polyethylene terephthalate as the above aromatic polycarboxylic acid. The above polyethylene terephthalate is a polyester resin obtained by polymerizing terephthalic acids and ethylene glycol. By using the above polyethylene terephthalate, the polyester resin (A) will have a structural unit derived from terephthalic acids of polyethylene terephthalate as a structural unit derived from an aromatic compound. The above 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, etc. The above 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.

[0032] When using the above aromatic polycarboxylic acids as a copolymer component of the polyester resin (A), the content is preferably 1 mol% or more and less than 50 mol%, more preferably 5 to 47 mol%, still more preferably 10 to 43 mol%, particularly preferably 15 to 40 mol%, and even more preferably 20 to 36 mol% based on the total amount of the polycarboxylic acids (a). If the content is too low, the cohesive force decreases, resulting in a decrease in adhesive force and a tendency that sufficient adhesive performance cannot be obtained. If the content is too high, the initial adhesive force (tack) tends to decrease.

[0033] (Aromatic polyol) Examples of the above aromatic polyol include divalent aromatic diols. Examples of the above divalent aromatic diol include, for example, 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.

[0034] When using the above aromatic polyol as a copolymer component of the polyester resin (A), the content is preferably 1 to 50 mol%, more preferably 5 to 40 mol%, still more preferably 10 to 30 mol% based on the total amount of the polyol (b). If the content is too low, the cohesive force decreases and the adhesive force tends to decrease. If the content is too high, the initial adhesive force tends to decrease.

[0035] In addition to the above compound (α1) and aromatic compounds, the polyester resin (A) used in the present polyester resin composition may use an aliphatic compound as a copolymer component.

[0036] [Aliphatic compound] Examples of the above aliphatic compound include aliphatic polycarboxylic acids and aliphatic polyols.

[0037] (Aliphatic polycarboxylic acids) Examples of the aliphatic polycarboxylic acids include divalent aliphatic dicarboxylic acids and polycarboxylic acids having three or more valences. 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, sebacic acids, 1,9-nonanedicarboxylic acids, decanedicarboxylic acids, etc.; acyclic aliphatic dicarboxylic acids such as fumaric acids, maleic acids, itaconic acids, thiodipropionic acids, diglycolic acids, etc. Examples of the cyclic aliphatic dicarboxylic acids include 1,3-cyclopentanedicarboxylic acids, 1,2-cyclohexanedicarboxylic acids, 1,4-cyclohexanedicarboxylic acids, 2,5-norbornanedicarboxylic acids, adamantanedicarboxylic acids, etc. Examples of the polycarboxylic acids having three or more valences include adamantanetricarboxylic acids, etc. These aliphatic polycarboxylic acids may be used alone or in combination of two or more.

[0038] From the viewpoint of improving the initial adhesiveness (tack), it is preferable that the aliphatic polycarboxylic acids contain acyclic aliphatic dicarboxylic acids having 4 or more carbon atoms (including the carbon atoms of the carboxy group), and among them, it is more preferable to contain acyclic aliphatic dicarboxylic acids having 9 to 12 carbon atoms (including the carbon atoms of the carboxy group) such as azelaic acids and sebacic acids.

[0039] When using the acyclic aliphatic dicarboxylic acids having 4 or more carbon atoms as the copolymerization component of the polyester resin (A), the content is preferably 95 mol% or less, more preferably 5 to 90 mol%, and particularly preferably 10 to 70 mol% with respect to the total amount of the polycarboxylic acids (a). If such a content ratio is too high, the adhesiveness tends to decrease or the resin crystallizes and sufficient adhesive performance cannot be obtained.

[0040] In addition, in order to increase the biomass content, it is preferable to use aliphatic polycarboxylic acids derived from plants as the aliphatic polycarboxylic acids. Examples of the aliphatic polycarboxylic acids derived from plants include sebacic acids derived from castor oil, succinic acids derived from corn, and the like.

[0041] (Aliphatic polyol) Examples of the aliphatic polyol include divalent aliphatic diols and trivalent or higher aliphatic polyalcohols. Examples of the divalent aliphatic diols include acyclic aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 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; cyclic aliphatic diols such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, spiroglycol, tricyclodecanedimethanol, adamantanediol, isosorbide, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and the like. Examples of the trivalent or higher aliphatic polyalcohols include pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,3,6-hexanetriol, adamantanetriol, and the like. These aliphatic polyols may be used alone or in combination of two or more.

[0042] Among these, it is preferable to incorporate a linear acyclic aliphatic diol in the polyol from the viewpoint of lowering the glass transition temperature (Tg) of the polyester resin (A) and improving the initial adhesive strength, more preferably a linear acyclic aliphatic diol having 2 to 18 carbon atoms, and particularly preferably ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, or 1,6-hexanediol. Of these, ethylene glycol is particularly preferable from the viewpoint of lowering the glass transition temperature (Tg) of the polyester resin (A) and improving the adhesiveness.

[0043] When the above-mentioned linear acyclic aliphatic diol is used as a copolymerization component of the polyester resin (A), the content thereof is preferably 1 to 100 mol %, more preferably 20 to 90 mol %, still more preferably 40 to 80 mol %, and particularly preferably 60 to 75 mol %, based on the total polyol (b). If the content is too low, it tends to be difficult to obtain stable resin formation.

[0044] The aliphatic polyol is preferably a plant-derived polyol in order to increase the biomass content. Examples of the plant-derived polyol include isosorbide, fatty acid ester diols derived from castor oil, bioethylene glycol, bio-1,3-propane glycol, biobutylene glycol, etc. Among these, bioethylene glycol and bio-1,3-propane glycol are preferred.

[0045] Furthermore, polyethylene terephthalate may be used as the linear acyclic aliphatic diol. As described above, polyethylene terephthalate is a polyester resin obtained by polymerizing terephthalic acids and ethylene glycol. Therefore, by using polyethylene terephthalate, the polyester resin (A) contains a structural unit derived from ethylene glycol derived from polyethylene terephthalate as a structural unit derived from the linear acyclic aliphatic diol. Furthermore, 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.

[0046] Furthermore, in order to form reaction sites in the polyester resin (A) with the polyisocyanate compound (B) described below and increase cohesion, it is preferable to use a trivalent or higher aliphatic polyol as the aliphatic polyol. For example, trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, and 1,2,6-hexanetriol can be used. These may be used alone or in combination of two or more. Among these, trimethylolpropane is particularly preferable because it is relatively less likely to form gels.

[0047] The content of the trihydric or higher aliphatic polyhydric alcohol is preferably 20 mol % or less, more preferably 0.1 to 10 mol %, and particularly preferably 0.5 to 5 mol %, based on the total amount of the polyol (b). If the content of the trihydric or higher aliphatic polyhydric alcohol is too high, it tends to be difficult to produce the polyester resin (A).

[0048] Also, as described above, it is preferable to use an aliphatic polyol derived from plants. However, when the biomass degree of the polycarboxylic acids (a) is high, an aliphatic polyol not derived from plants may be used from the viewpoint of ease of polycondensation. However, even in that case, in order to increase the biomass degree, it is preferable to use an acyclic aliphatic diol having a linear structure with 4 or less carbon atoms, and particularly preferably an acyclic aliphatic diol having a linear structure with 2 to 3 carbon atoms. Examples of the acyclic aliphatic diol having a linear structure with 4 or less carbon atoms include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and the like. That is, when an aliphatic polyol having 4 or less carbon atoms, which is small, is used, the weight ratio of the carboxylic acids (a) having a high biomass degree as the polyester resin (A) increases, and thus the biomass degree can be increased.

[0049] [Production of polyester resin (A)] In the present invention, the polyester resin (A) can be produced by subjecting polycarboxylic acids (a) and a polyol (b) to a polycondensation reaction by a known method in the presence of a catalyst. In the polycondensation reaction, first, an esterification reaction or a transesterification reaction is carried out, and then a 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. Further, when using the aforementioned polyethylene terephthalate, polyethylene terephthalate may be blended together with the polycarboxylic acids (a) and the polyol (b).

[0050] 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, and 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 the high catalytic activity and the hue of the resulting reaction product.

[0051] The compounding amount of the above catalyst is preferably 1 to 10,000 ppm, particularly preferably 10 to 5,000 ppm, and even more preferably 20 to 3,000 ppm based on the total copolymerization components (by weight). 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 the reaction time, and side reactions tend to occur easily.

[0052] Regarding the reaction temperature during the esterification reaction or the transesterification reaction, 200 to 300 °C is preferable, particularly preferably 210 to 280 °C, and even more preferably 220 to 260 °C. If the reaction temperature is too low, the reaction tends not to proceed sufficiently. If it is too high, side reactions such as decomposition tend to occur easily. Also, the pressure during the reaction is usually normal pressure.

[0053] As the reaction conditions for the polycondensation reaction carried out after the above esterification reaction or transesterification reaction, the same catalyst as that used in the above esterification reaction or transesterification reaction is further compounded in a similar 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 the reaction temperature is too low, the reaction tends not to proceed sufficiently. If it is too high, side reactions such as decomposition tend to occur easily.

[0054] Thus, a polyester resin (A) containing a structural unit derived from the compound (α1) is obtained.

[0055] In the above polyester resin (A), the content ratio of the structural unit derived from the compound (α1) is 25 mol% or more of the entire polyester resin (A), preferably 30 mol% or more, more preferably 35 mol% or more. The upper limit is usually 60 mol%, preferably 55 mol%. If such a content is too small, it becomes too hard and the adhesive strength decreases. If such a content is too large, it becomes too soft and the adhesive properties slightly decrease.

[0056] The number average molecular weight of the polyester resin (A) used in the present polyester resin composition is 3000 or more, preferably 3500 to 50000, more preferably 4000 to 40000, particularly preferably 5000 to 30000, especially preferably 6000 to 20000, and most preferably 7000 to 15000. If the number average molecular weight is too large, the handleability will decrease, so a large amount of solvent is required, resulting in a large environmental burden. If the number average molecular weight is too small, the adhesive physical properties when used as an adhesive will decrease.

[0057] The weight average molecular weight of the above polyester resin (A) is preferably 10000 or more, more preferably 10000 to 500000, still more preferably 20000 to 300000, particularly preferably 30000 to 250000, especially preferably 40000 to 200000, and most preferably 50000 to 150000. If the weight average molecular weight is too small, the adhesive physical properties when used as an adhesive tend to decrease. If the weight average molecular weight is too large, the handleability will decrease, so a large amount of solvent is required, and the environmental burden tends to increase.

[0058] 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: 16000 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").

[0059] Also, 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, and particularly preferably 75% or more. The upper limit is 100%. If such a biomass content is low, the reduction of the environmental burden tends to be insufficient.

[0060] Here, the biomass content of the polyester resin (A) refers to the weight ratio of the plant-derived raw materials used in producing the polyester resin (A) incorporated into the resin relative to the total weight of the polyester resin (A), and is calculated as follows: The biomass degree of the polycarboxylic acid (a) and the polyol (b) is determined from the weighted average of the respective biomass degrees. In addition, the value obtained by any of the following calculation methods may be within the above range.

[0061] (Calculation method) <When polycondensation reaction occurs> Biomass ratio (%) = [(number of moles of carbon of plant-derived monomer calculated from the molar ratio of polycarboxylic acids (a) and polyol (b) in polyester resin (A)) / (number of moles of carbon of all constituent monomers in polyester resin (A))] × 100

[0062] <When no polycondensation reaction is involved> Biomass ratio (%) = [(number of moles of carbon of plant-derived monomer in polyester resin (A)) / (number of moles of carbon of all constituent monomers in polyester resin (A))] × 100

[0063] The biomass ratio can also be determined by analyzing the composition ratio by NMR and calculating the carbon number of the plant-derived monomer / total carbon number.

[0064] Furthermore, the biomass degree can also be measured by the method described in "Technology for Determining the Origin of Biofuels Using Natural Radioactive Carbon C-14," Tokyo Metropolitan Industrial Technology Research Center Research Report, No. 4, 2009.

[0065] Methods for adjusting the biomass degree within a predetermined range include using mainly plant-derived polycarboxylic acids or plant-derived polyols, but it is particularly preferable to use plant-derived polycarboxylic acids, as this allows for an efficient increase in the biomass degree.

[0066] In the present invention, it is preferable from the viewpoint of reducing environmental impact that the recycled carbon usage rate of the polyester resin (A) is 50% or more, more preferably 60% or more, still more preferably 70% or more, and particularly preferably 75% or more. The upper limit is 100%. Here, the recycled carbon usage rate of the polyester resin (A) refers to the weight ratio of the raw material containing recycled carbon used when producing the polyester resin (A) to the total weight of the polyester resin (A). Examples of the raw material containing recycled carbon include plant-derived raw materials and recycled polyethylene terephthalate (recycled PET).

[0067] The calculation method of the recycled carbon usage rate can be calculated by the same method as the calculation method of the biomass degree described above. That is, it is as follows. (Calculation method) <When accompanied by a polycondensation reaction> Recycled carbon usage rate (%) = [(number of moles of recycled carbon calculated from the molar ratio of polycarboxylic acids (a) and polyols (b) in the polyester resin (A)) / (number of moles of carbon of all constituent monomers in the polyester resin (A))] × 100

[0068] <When not accompanied by a polycondensation reaction> Recycled carbon usage rate (%) = [(number of moles of recycled carbon in the polyester resin (A)) / (number of moles of carbon of all constituent monomers in the polyester resin (A))] × 100

[0069] The glass transition temperature (Tg) of the polyester resin (A) is preferably -90 to 20 °C, particularly preferably -60 to 0 °C, and still more preferably -50 to -20 °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.

[0070] The glass transition temperature (Tg) is measured using a differential scanning calorimeter DSC Q20 manufactured by TA Instruments, Inc. The measurement temperature range is −90 to 100° C., and the temperature rise rate is 10° C. / min.

[0071] The ester group concentration of the polyester resin (A) is usually 2 mmol / g or more, preferably 3 to 10 mmol / g, more preferably 3.6 to 6 mmol / g, and particularly preferably 4.2 to 5 mmol / g. If the ester group concentration is too low, the polyester resin (A) becomes soft, and if it is too soft, the adhesive properties tend to deteriorate.

[0072] The ester group concentration (mmol / g) refers to the number of moles of ester bonds in 1 g of polyester resin (A), and can be calculated from the amounts charged, for example. The calculation method is to divide the number of moles of the polycarboxylic acid (a) or polyol (b), whichever is charged in smaller amounts, by the total weight, and an example of the calculation formula is shown below. When the polycarboxylic acid (a) and the polyol (b) are charged in equal molar amounts, either of the following calculation formulas may be used. Furthermore, when a monomer having both a carboxyl group and a hydroxyl group is used, or when polyester is produced from caprolactone or the like, the calculation method will be changed appropriately.

[0073] <When the amount of polycarboxylic acids (a) is small> Ester group concentration (mmol / g) = [(X1 / x1 × m1 + X2 / x2 × m2 + X3 / x3 × m3 ) / Z] × 1000 X1, X2, X3: Amount (g) of polycarboxylic acid (a) added x1, x2, x3: molecular weight of polycarboxylic acid (a) m1, m2, m3: Number of carboxyl groups per molecule of polycarboxylic acid (a) Z: Finished weight (g) <When the amount of polyol (b) is small> Ester group concentration (mmol / g) = [((Y1 / y1 × n1 + Y2 / y2 × n2 + Y3 / y3 × n3 ···) / Z)] × 1000 Y1, Y2, Y3 ···: Charge amount of polyol (b) (g) y1, y2, y3 ···: Molecular weight of polyol (b) n1, n2, n3 ···: Number of hydroxyl groups per molecule of polyol (b) Z: Final weight (g)

[0074] Also, the above ester group concentration can be measured by a known method using NMR or the like. For example, the ester group concentration of the polyester resin (A) can be determined 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).

[0075] As a method for adjusting the above ester group concentration, for example, a method of selecting a polyol having 4 or less carbon atoms as the polyol (b), a method of increasing the content of linear carboxylic acids as the polycarboxylic acids (a), a method of combining both, etc. can be mentioned.

[0076] The heat of crystal melting measured by a differential scanning calorimeter for 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 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.

[0077] Examples of methods for adjusting the heat of crystalline fusion include a method of appropriately using polycarboxylic acids having an alkyl group on the side chain or a polyol having an alkyl group on the side chain, and a method of using three or more, preferably four or more, copolymerizable monomer components.

[0078] The acid value of the polyester resin (A) is preferably 10 mgKOH / g or less in order to prevent hydrolysis and improve durability, more preferably 5 mgKOH / g or less, particularly preferably 2 mgKOH / g or less, particularly preferably 1 mgKOH / g or less, and most preferably 0.1 mgKOH / g or less. If the acid value is too high, durability tends to decrease. The acid value can be adjusted, for example, by increasing the proportion of polyol during the esterification reaction or transesterification reaction or by adjusting the reaction conditions. The lower limit of the acid value is usually 0 mgKOH / g.

[0079] The acid value of the polyester resin (A) is determined by neutralization titration in accordance with JIS K0070. The acid value in the present invention means the content of carboxy groups in the polyester resin (A). The carboxy groups include those in a carboxylate ion state in which the carboxy groups are neutralized with a basic compound.

[0080] As described above, the polyester resin composition preferably contains, in addition to the polyester resin (A1), a polyvalent isocyanate compound (B), a hydrolysis inhibitor (C), and, as necessary, a tackifier (D), a urethanization catalyst (E), an antioxidant (F), and the like. In addition to the polyester resin (A), the pressure-sensitive adhesive composition preferably contains a polyisocyanate compound (B), a hydrolysis inhibitor (C), and, if necessary, a tackifier (D), a urethanization catalyst (E), an acid value inhibitor (F), and the like.

[0081] <Polyisocyanate Compound (B)> It is preferable that the present polyester resin composition or the present pressure-sensitive adhesive composition further contains a polyvalent isocyanate compound (B) as a crosslinking agent. By incorporating 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 a pressure-sensitive adhesive can be improved.

[0082] Examples of such polyvalent isocyanate compounds (B) include aromatic isocyanate-based crosslinking agents such as tolylene diisocyanate-based crosslinking agents like 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, xylylene diisocyanate-based crosslinking agents like 1,3-xylylene diisocyanate, diphenylmethane-based crosslinking agents like diphenylmethane-4,4-diisocyanate, and naphthalene diisocyanate-based crosslinking agents like 1,5-naphthalene diisocyanate; alicyclic isocyanate-based 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-based crosslinking agents such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; and adducts, biuret bodies, isocyanurate bodies, etc. of the above isocyanate compounds. In addition, the above polyvalent isocyanate compounds (B) in which the isocyanate moiety is blocked with phenol, lactam, etc. can also be used. These polyvalent isocyanate compounds (B) may be used alone or in combination of two or more.

[0083] 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, based on 1 equivalent of at least one of the hydroxyl group and carboxyl group contained in the polyester resin (A), the polyvalent isocyanate compound (B) is preferably contained in a proportion 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.

[0084] In addition, 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.

[0085] <Hydrolysis inhibitor (C)> The above hydrolysis inhibitor (C) is contained as necessary to ensure the long-term durability of the polyester resin composition or the pressure-sensitive adhesive composition. As the above hydrolysis inhibitor (C), conventionally known ones can be used. For example, compounds that react and bond with the carboxyl group terminal 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 preferred in that they have a high effect of eliminating the catalytic activity of protons derived from the carboxyl group terminal.

[0086] 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 carbodiimidization catalyst.

[0087] Furthermore, a high molecular weight polycarbodiimide in which the terminal isocyanate groups are blocked by a blocking agent is preferable in terms of storage stability. Examples of the blocking agent include a compound having active hydrogen that reacts with an isocyanate group, or a compound having an isocyanate group. For example, monoalcohols, monocarboxylic acids, monoamines, and monoisocyanates having one substituent selected from a carboxy group, an amino group, and an isocyanate group can be mentioned.

[0088] Examples of such high molecular weight polycarbodiimides include those obtained by subjecting the following diisocyanates to a decarboxylation condensation reaction.

[0089] 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 polycarbodiimides may be synthesized or commercially available products may be used.

[0090] 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.

[0091] Examples of the epoxy group-containing compound include, for example, glycidyl ester compounds and glycidyl ether compounds, etc.

[0092] Examples of the glycidyl ester compound include glycidyl benzoate, glycidyl t-butylbenzoate, glycidyl p-toluylate, 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 methylterephthalate, 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.

[0093] Examples of the glycidyl ether compound include 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 bisglycidyl polyethers obtained by the reaction of bisphenols such as 2,2-bis-(4-hydroxyphenyl)propane and 2,2-bis-(4-hydroxyphenyl)methane with epichlorohydrin. These can be used alone or in combination of two or more.

[0094] 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.

[0095] The hydrolysis inhibitor (C) preferably has low volatility, and therefore it is preferable to use one with a high number average molecular weight, which is usually 300 to 10,000, preferably 1,000 to 5,000. Furthermore, from the viewpoint of hydrolysis resistance, it is preferable to use a hydrolysis inhibitor (C) having a high weight-average molecular weight. The weight-average molecular weight of the hydrolysis inhibitor (C) is preferably 500 or more, more preferably 1000 or more, even more preferably 2000 or more, and particularly preferably 3000 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. If the molecular weight is too large, the compatibility with the polyester resin (A) tends to decrease.

[0096] Among the hydrolysis inhibitors (C), it is preferable to use a carbodiimide group-containing compound, and in this case, the carbodiimide equivalent is preferably 50 to 10,000, particularly 100 to 1,000, and further preferably 150 to 500. The carbodiimide equivalent indicates the chemical formula weight per carbodiimide group.

[0097] When the hydrolysis inhibitor (C) is used, its content is preferably 0.01 to 10 parts by weight, particularly preferably 0.1 to 5 parts by weight, and even more preferably 0.2 to 3 parts by weight, relative to 100 parts by weight of the polyester resin (A). If the content is too high, turbidity tends to occur due to poor compatibility with the polyester resin (A), while if the content is too low, sufficient durability tends to be difficult to obtain.

[0098] The content of the hydrolysis inhibitor (C) is preferably optimized depending on the acid value of the polyester resin (A), and the molar ratio [(y) / (x)] of the total number of moles (y) of functional groups of the hydrolysis inhibitor (C) in the pressure-sensitive adhesive composition to the total number of moles (x) of acidic functional groups of the polyester resin (A) in the pressure-sensitive adhesive composition is preferably 0.5≦(y) / (x), particularly preferably 1≦(y) / (x)≦1000, and even more preferably 1.5≦(y) / (x)≦100. If the molar ratio of (y) to (x) is too low, the moisture and heat resistance tends to decrease, whereas 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 tend to decrease.

[0099] <Tackifier (D)> The present polyester resin composition or the present pressure-sensitive adhesive composition preferably contains a tackifier (D) in order to improve the adhesive properties.

[0100] The tackifier (D) is not particularly limited, and conventionally known tackifiers can be used. Examples of the tackifier (D) include hydrocarbon tackifier resins, terpene resins, phenolic resins, rosin resins, xylene resins, epoxy resins, polyamide resins, ketone resins, and elastomer resins. These may be used alone or in combination of two or more. Of these, hydrocarbon tackifier resins and terpene resins are preferred. It is particularly preferred that the tackifier (D) contains at least one hydrocarbon tackifier resin, and the hydrocarbon tackifier resin preferably accounts for 30% by weight or more, preferably 50% by weight or more, and more preferably 70% by weight or more of the total tackifier.

[0101] 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.

[0102] 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, and terpene phenol resins are particularly preferred.

[0103] Examples of the phenolic resin include condensates of various phenols such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcinol, etc. and formaldehyde. Further, resol obtained by subjecting the phenols and formaldehyde to an addition reaction under an alkali catalyst, novolak obtained by subjecting the phenols and formaldehyde to a condensation reaction under an acid catalyst, rosin-modified phenolic resins obtained by adding phenol to unmodified or modified rosin or derivatives thereof under an acid catalyst and subjecting them to thermal polymerization, etc. can be used.

[0104] Examples of the rosin resin include rosin resin, polymerized rosin resin, hydrogenated rosin resin, rosin ester resin, hydrogenated rosin ester resin, rosin phenolic resin, polymerized rosin ester, etc. Specific examples include 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 of these. Commercially available products include "Harie Star TF," "Harlitack 8LJA," "Harlitack PH," "Harlitack FK100," and "Harlitack PCJ," manufactured by Harima Chemicals Co., Ltd.

[0105] The tackifier (D) preferably has an acid value of 30 mgKOH / g or less, particularly preferably 10 mgKOH / g or less, further preferably 6 mgKOH / g or less, and particularly preferably 3 mgKOH / g or less. When multiple types of tackifiers (D) are used in combination, the average of their acid values is preferably within the above range.

[0106] 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 165° C., more preferably 100 to 160° C., still more preferably 120 to 155° C., and particularly preferably 135 to 150° C. If the softening point is within the above range, adhesive properties (adhesive strength, cohesive strength) tend to be improved.

[0107] The tackifier (D) is preferably plant-derived in order to maintain a high biomass content in the polyester resin composition or the entire pressure-sensitive adhesive composition. Examples of plant-derived tackifiers include terpene resins and rosin resins.

[0108] The tackifier (D) preferably contains an aromatic structural unit from the viewpoints of improving cohesive strength 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.

[0109] When a tackifier (D) is used, its content is preferably 2 to 200 parts by weight, more preferably 5 to 150 parts by weight, even more preferably 8 to 100 parts by weight, and particularly preferably 10 to 80 parts by weight, or 20 to 50 parts by weight, relative to 100 parts by weight of the polyester resin (A). When the content is within the above range, adhesive properties (adhesive strength, cohesive strength) tend to be improved.

[0110] <Urethanization catalyst (E)> The present polyester resin composition or the present pressure-sensitive adhesive composition more preferably contains a urethanization catalyst (E) in terms of reaction rate.

[0111] Examples of the urethanization catalyst (E) include organometallic compounds, tertiary amine compounds, etc. These can be used alone or in combination of two or more.

[0112] Examples of the organometallic compounds include zirconium compounds, iron compounds, tin compounds, titanium compounds, lead compounds, cobalt compounds, and zinc compounds.

[0113] Examples of the zirconium compound include zirconium naphthenate and zirconium acetylacetonate. Examples of the iron-based compound include iron acetylacetonate and iron 2-ethylhexanoate. Examples of the tin compounds include dibutyltin dichloride, dibutyltin oxide, and dibutyltin dilaurate. Examples of the titanium compound include dibutyltitanium dichloride, tetrabutyl titanate, butoxytitanium trichloride, and the like. Examples of the lead compound include lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate, and the like. Examples of the cobalt compound include cobalt 2-ethylhexanoate, cobalt benzoate, and the like. Examples of the zinc compound include zinc naphthenate, zinc 2-ethylhexanoate, and the like.

[0114] Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo-(5,⁢4,⁢0)-undecene-7, and the like.

[0115] Among these urethanization catalysts (E), organometallic compounds are preferred in terms of reaction rate and pot life of the adhesive layer, and zirconium compounds are particularly preferred. Further, it is preferable to use acetylacetone in combination with the urethanization catalyst (E) as a catalyst action inhibitor. By containing acetylacetone, it is preferable in that it suppresses the catalytic action at low temperatures and lengthens the pot life.

[0116] 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 with respect to 100 parts by weight of the polyester resin (A). If such 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.

[0117] <Antioxidant (F)> This polyester resin composition or this adhesive composition more preferably contains an antioxidant (F) from the viewpoint of improving the stability of the resin.

[0118] Examples of the antioxidant (F) include hindered phenol antioxidants, amine antioxidants, sulfur antioxidants, phosphoric acid antioxidants, and the like. Among them, it is preferably at least one selected from hindered phenol antioxidants, amine antioxidants, and phosphoric acid antioxidants, and particularly preferably an antioxidant composed of a hindered phenol 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.

[0119] 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 for glue residue on the adherend to easily occur, and if it is too large, there is a tendency for the adhesive physical properties to decrease.

[0120] In this polyester resin composition or this adhesive composition, in addition to the above polyester resin (A), polyvalent isocyanate compound (B), hydrolysis inhibitor (C), tackifier (D), urethanization catalyst (E), antioxidant (F), additives such as softeners, ultraviolet absorbers, stabilizers, antistatic agents, etc. and other inorganic or organic fillers, powders such as metal powders and pigments, particulate additives, etc. can be blended within a range that does not impair the effects of the present invention. Also, it may contain a small amount of impurities contained in the production raw materials, etc. of the constituent components of this polyester resin composition or this adhesive composition. These can be used alone or in combination of two or more.

[0121] Such a polyester resin composition or pressure-sensitive adhesive composition can be obtained, for example, by preparing the 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.

[0122] It is preferable from the viewpoint of reducing environmental load that the biomass content of such a polyester resin composition or pressure-sensitive adhesive composition is 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 biomass content of the above polyester resin composition or pressure-sensitive adhesive composition 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 polyester resin composition or pressure-sensitive adhesive composition refers to the ratio of the weight of plant-derived raw materials used in producing the polyester resin composition or pressure-sensitive adhesive composition to the total weight of the polyester resin composition or pressure-sensitive adhesive 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 or pressure-sensitive adhesive composition) × (weight of each plant-derived raw material used in producing the polyester resin composition or pressure-sensitive adhesive composition))] / (total weight of the polyester resin composition or pressure-sensitive adhesive composition) × 100

[0123] Also, the biomass content of the above polyester resin composition or pressure-sensitive adhesive composition can also be measured by the method using NMR or the method using natural radioactive carbon C-14 described above. Among the above calculation methods, it is sufficient that the value obtained by any method is within the above range.

[0124] This polyester resin composition or this adhesive composition preferably has a recycled carbon usage rate of 50% or more from the viewpoint of reducing environmental impact, more preferably 60% or more, still more preferably 70% or more, and particularly preferably 75% or more. The upper limit is 100%. Here, the recycled carbon usage rate of the above polyester resin composition or this adhesive composition refers to the ratio of the weight of the raw materials containing recycled carbon used in manufacturing the polyester resin composition or this adhesive composition to the total weight of the polyester resin composition or this adhesive composition. Examples of the raw materials containing recycled carbon include plant-derived raw materials, recycled polyethylene terephthalate (recycled PET), etc. The recycled carbon usage rate of the above polyester resin composition or this adhesive composition can be adjusted according to the types and blending amounts of the polyester resin (A) and other blending components. Also, the recycled carbon usage rate of the polyester resin composition or this adhesive composition can be determined, for example, by the following formula. Recycled carbon usage rate (%) = [(Sum of (Recycled carbon usage rate of each plant-derived raw material used in manufacturing the polyester resin composition or this adhesive composition) × (Weight of each raw material using recycled carbon used in manufacturing the polyester resin composition or this adhesive composition))] / (Total weight of the polyester resin composition or this adhesive composition) × 100

[0125] The polyester resin composition can be suitably used as an adhesive composition. Hereinafter, the adhesive composition composed of the polyester resin composition and this adhesive composition are collectively referred to simply as "adhesive composition". Also, an adhesive (hereinafter referred to as "this adhesive") according to an embodiment of the present invention is obtained by crosslinking the above adhesive composition.

[0126] And an adhesive sheet (hereinafter referred to as "this adhesive sheet") according to an embodiment of the present invention has an adhesive layer containing the above adhesive, and such an adhesive layer is preferably formed on one or both sides of a support substrate. In the present invention, the term "sheet" is defined to include "film" and "tape".

[0127] <Adhesive sheet> This adhesive sheet can be produced, for example, in the following manner. 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 above adhesive composition is coated 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.

[0128] Alternatively, the adhesive composition is coated and dried on a release sheet, a substrate is laminated on the adhesive layer surface on the opposite side, and if necessary, cured to obtain the adhesive sheet.

[0129] Furthermore, 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.

[0130] 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 bonded to the adherend.

[0131] Examples of the base material include 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. Examples also include a sheet made of at least one synthetic resin selected from the group consisting of these; metal foils of aluminum, copper, and iron; papers such as fine 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 a single layer or as a multi-layer body in which two or more types are laminated.

[0132] Among these, base materials made of polyethylene terephthalate and polyimide are particularly preferred, and polyethylene terephthalate is particularly preferred in terms of excellent adhesiveness to the adhesive.

[0133] 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, or 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.

[0134] The thickness of the base material is preferably, for example, 1 to 1000 μm, particularly preferably 2 to 500 μm, and even more preferably 3 to 300 μm.

[0135] As the release sheet, for example, a sheet made of any of the various synthetic resins exemplified above as the substrate, paper, cloth, nonwoven fabric, etc. that has been subjected to a release treatment can be used. As the release sheet, it is preferable to use a silicone-based release sheet.

[0136] The pressure-sensitive adhesive composition may be applied using, for example, a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, comma coater, or the like.

[0137] The conditions for the aging treatment are generally room temperature (23°C) to 70°C, and the time is generally 1 to 30 days. Specifically, the treatment may be carried out under conditions such as 1 to 20 days at 23°C, preferably 3 to 14 days at 23°C, or 1 to 10 days at 40°C.

[0138] As for 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.

[0139] The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet and substrate-less double-sided pressure-sensitive 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 the pressure-sensitive adhesive layer is too thin, the adhesive strength tends to decrease, while if it is too thick, it becomes difficult to apply uniformly and problems such as air bubbles entering the coating film tend to occur. When considering impact absorption properties, a thickness of 50 μm or more is preferable.

[0140] The thickness of the adhesive layer is determined by subtracting the measured thickness of the constituent members other than the adhesive layer from the measured thickness of the entire adhesive sheet using a Mitutoyo ID-C112B.

[0141] 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, particularly preferably 20 to 80% by weight, and even more preferably 30 to 70% by weight from the viewpoints of durability performance and adhesive strength. 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.

[0142] 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 should be subtracted.

[0143] It is preferable that the adhesive strength of this pressure-sensitive adhesive sheet under the following conditions is 7 N / 25 mm or more, more preferably 10 N / 25 mm or more, and particularly preferably 12 N / 25 mm or more. Also, the upper limit of the adhesive strength is usually 100 N / 25 mm, preferably 50 N / 25 mm. [Conditions] Attach the pressure-sensitive adhesive sheet to an adherend of a polypropylene plate, let it stand still for 30 minutes in an environment of 23°C and 50% RH, and then measure the 180-degree peel strength (N / 25 mm) at a peel rate of 300 mm / min with respect to the adherend.

[0144] Furthermore, such a pressure-sensitive adhesive sheet of the present invention may be provided with a release sheet on the outside of the pressure-sensitive adhesive layer for protection as needed. Also, in the case of a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is formed on one side of the base material, it is also possible to protect the pressure-sensitive adhesive layer by performing a peeling treatment on the surface of the base material opposite to the pressure-sensitive adhesive layer and using the peeled surface.

[0145] This adhesive can be used for bonding various members, and in particular, it is used for single-sided or double-sided adhesive sheets for bonding optical members, single-sided or double-sided adhesive sheets for fixing members of portable electronic devices, fixing electronic members, etc.

Examples

[0146] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, "parts" and "%" mean weight basis.

[0147] In addition, regarding the measurement of the number average molecular weight, weight average molecular weight, biomass degree, recycled carbon usage rate, glass transition temperature, gel fraction of the adhesive layer, biomass degree, and recycled carbon usage rate of the polyester resin composition (adhesive composition) in the following examples, the measurement was carried out according to the aforementioned method.

[0148] The polyester resin was produced by the following method (see Table 1).

[0149] [Examples 1 - 2, Comparative Examples 1 - 2] [Production of Polyester Resins (A) [A - 1, A - 2], (A') [A' - 1 - A' - 2]] Polycarboxylic acids and polyols as shown in Table 1 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 with respect to the polycarboxylic acids. The temperature was gradually raised to 240°C, and an esterification reaction was carried out over 4 hours. Then, the internal temperature was raised to 260°C, tetrabutyl titanate was charged at 0.2 mmol / mol with respect to the polycarboxylic acids as a catalyst, the pressure was reduced to 1.33 - 2.66 hPa, and a polymerization reaction was carried out over 2 - 3 hours to produce the polyester resin (A). The composition ratio, various physical properties, etc. of the obtained polyester resin (A) were as shown in Table 2 below. In the above production, the plant-derived raw materials were hydrodistilled dimer acid with 44 carbon atoms (hydrodistilled C44 dimer acid) and hydrodistilled dimer acid with 36 carbon atoms (hydrodistilled C36 dimer acid). In addition, part of the terephthalic acid and ethylene glycol were derived from polyethylene terephthalate (PET).

[0150] [Table 1]

[0151] [Table 2]

[0152] Next, prior to preparing a polyester resin composition (adhesive composition), the following components were prepared.

[0153] [Polyisocyanate compound (B)] Polyisocyanate compound (B-1): "Coronate L55E, solids concentration 55%" (manufactured by Tosoh Corporation)

[0154] [Hydrolysis inhibitor (C)] Carbodiimide compound (C-1): "Carbodilite V-09GB, solid content 70%" (Nisshinbo Chemical Co., Ltd.)

[0155] [Tackifier (D)] Terpene phenol resin (D-1): "YS Polyster T160, softening point 160°C" (Yasuhara Chemical Co., Ltd.) Terpene phenol resin (D-2): "YS Polyster G150, softening point 150°C" (Yasuhara Chemical Co., Ltd.) Terpene phenol resin (D-3): "YS Polyster S145, softening point 145°C" (Yasuhara Chemical Co., Ltd.)

[0156] Using the above polyester resin (A) or (A'), polyisocyanate compound (B), hydrolysis inhibitor (C), and tackifier (D), a polyester resin composition (adhesive composition) was prepared as shown below in the formulation shown in Table 3, and an adhesive sheet was produced.

[0157] [Examples 1-1 to 2-4, Comparative Examples 1-1 to 2-4] The polyester resin (A) or (A') obtained above was diluted with ethyl acetate to a solid content of 50%, and a polyisocyanate compound (B-1) and a carbodiimide compound (C-1) were added in the proportions (solid content proportions) shown in Table 3, and the mixture was stirred and mixed to obtain a polyester resin composition (adhesive composition). The obtained pressure-sensitive adhesive composition was applied to a polyethylene terephthalate (PET) film (thickness: 38 μm) so that the thickness after drying would be approximately 25 μm, and then dried for 3 minutes at 100° C. to form a pressure-sensitive adhesive layer. A release-treated PET film (release film) was then attached to the pressure-sensitive adhesive layer to protect its surface, and the layer was aged for 10 days in an atmosphere at a temperature of 40° C. to obtain a pressure-sensitive adhesive sheet.

[0158] The resulting pressure-sensitive adhesive sheets of the Examples and Comparative Examples were evaluated as follows, and the evaluation results are shown in Table 3 below.

[0159] <Initial adhesive strength (peel strength) (against SUS-BA)> A SUS-BA plate was prepared as the adherend. The pressure-sensitive adhesive sheet obtained above was cut to 25 mm x 200 mm in an environment of 23 °C and 50% RH, after which the release film was peeled off, and the pressure-sensitive adhesive layer side was placed against the SUS-BA plate, and a 2 kg roller was pressed back and forth to adhere the sheet. After leaving the sheet to stand for 30 minutes in the same atmosphere, the 180-degree peel strength (N / 25 mm) was measured at a peel rate of 300 mm / min using an autograph (Shimadzu Corporation, Autograph AGS-H 500N), and the peeling state was visually observed.

[0160] <Adhesion strength (peel strength) after 72 hours (against SUS-BA)> A SUS-BA plate was prepared as the adherend. The pressure-sensitive adhesive sheet obtained above was cut to 25 mm x 200 mm in an environment of 23 °C and 50% RH, after which the release film was peeled off, and the pressure-sensitive adhesive layer side was placed against the SUS-BA plate and pressure-bonded by reciprocating a 2 kg roller. After leaving the sheet in the same atmosphere for 72 hours, the 180° peel strength (N / 25 mm) was measured at a peel rate of 300 mm / min using an autograph (Shimadzu Corporation, Autograph AGS-H 500N), and the peeling state was visually observed.

[0161] <Initial adhesive strength (peel strength) (vs. PP)> A polypropylene (PP) plate was prepared as the adherend. The pressure-sensitive adhesive sheet obtained above was cut to 25 mm x 200 mm in an environment of 23 °C and 50% RH, after which the release film was peeled off, and the pressure-sensitive adhesive layer side was placed against the PP plate, and a 2 kg roller was pressed back and forth to adhere the sheet. After leaving the sheet to stand for 30 minutes in the same atmosphere, the 180-degree peel strength (N / 25 mm) was measured at a peel rate of 300 mm / min using an autograph (Shimadzu Corporation, Autograph AGS-H 500N), and the peeling state was visually observed.

[0162] <Holding force (cohesive force)> The adhesive sheet obtained above was attached to SUS304 as the adherend in accordance with JIS Z-0237 with an area of 25 mm x 25 mm, and then left to stand at 80°C for 20 minutes. A load of 1 kg was applied to the sheet, and the displacement after 24 hours was measured.

[0163] [Table 3]

[0164] From the results in Table 3 above, the adhesive sheets of Examples 1-1 to 2-4 had excellent adhesion to metal substrates both initially and over time, and also had the desired adhesion even to substrates that are difficult to adhere to, such as polyolefin-based resins, and had an excellent balance of adhesive strength and holding power. In addition, although the pressure-sensitive adhesive sheets of Comparative Examples 1-1 to 2-4 are excellent in the initial and aged adhesiveness to a metal adherend, they are inferior in the adhesive physical properties to a polyolefin adherend, and do not satisfy all of the effects of the invention.

Industrial Applicability

[0165] Even when using a polyester resin with a high biomass content, the present polyester resin composition or the present adhesive composition has an excellent effect on the adhesive physical properties to various adherends such as metals and plastics when used as an adhesive, and is 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. A polyester resin composition containing a polyester resin, wherein the polyester resin contains structural units derived from polycarboxylic acids (a) and polyols (b), and as the structural units derived from at least one of the polycarboxylic acids (a) and polyols (b), it contains structural units derived from at least one compound (α1) selected from dimer acids having 44 carbon atoms and dimer diols having 44 carbon atoms, and the content ratio of the structural units derived from at least one compound (α1) of the dimer acids having 44 carbon atoms and dimer diols is 25 mol% or more based on the total of the structural units derived from polycarboxylic acids (a) and polyols (b), and it is a polyester resin (A1) having a number average molecular weight of 3000 or more (however, excluding polyester resins having a hydroxyl value of 30 mgKOH / g or more).

2. The polyester resin composition according to Claim 1, wherein the weight average molecular weight of the polyester resin (A1) is 10000 or more.

3. The polyester resin composition according to Claim 1 or 2, wherein the biomass degree of the polyester resin composition is 50% or more.

4. The polyester resin composition according to any one of Claims 1 to 3, further containing a polyisocyanate compound (B).

5. The polyester resin composition according to any one of Claims 1 to 4, further containing a hydrolysis inhibitor (C).

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