JP2022188511A - Polyester-based resin composition, pressure-sensitive adhesive composition, pressure-sensitive adhesive, pressure-sensitive adhesive sheet and double-sided pressure-sensitive adhesive sheet - Google Patents

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

The present invention is a polyester-based resin composition containing structural units derived from a polycarboxylic acid having a furan skeleton, and when used as an adhesive, the polyester-based resin has excellent adhesive physical properties such as adhesive strength and holding power. The present invention relates to a composition, a pressure-sensitive adhesive composition containing the same, a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet and a double-sided pressure-sensitive adhesive sheet.

In recent years, from the viewpoint of miniaturization and weight reduction of products, adhesives have come to be used for joining parts. Adhesives using polyester-based resins, which are excellent in strength, are also being studied.

On the other hand, in recent years, as part of measures against the depletion of fossil resources and global warming, the use of plant-derived raw materials, which are renewable resources, has been recommended. There is a demand for adhesives with a high degree of hardness. Among them, as an aromatic plant-derived compound, an adhesive using a polyvalent carboxylic acid having a furan skeleton has attracted attention.

As a polyester-based resin using a polyvalent carboxylic acid having such a furan skeleton, for example, in Patent Document 1, a linear chain having 5 to 12 carbon atoms and containing 10 mol% or more of a furandicarboxylic acid component as a dicarboxylic acid component is disclosed. Copolyester resins containing 25 mol % or more of one or more selected from the group consisting of aliphatic dicarboxylic acids and linear aliphatic glycols having 5 to 12 carbon atoms have been proposed. Further, in the same document, a linear aliphatic dicarboxylic acid having 5 to 12 carbon atoms containing 80 mol% or more of a furandicarboxylic acid component and 30 mol% or more of an aliphatic glycol having 4 to 9 carbon atoms and having a side chain is described. Copolyester resins containing 25 mol % or less of one or more selected from the group consisting of acids and linear aliphatic glycols having 5 to 12 carbon atoms have also been proposed.
These copolyester resins are useful as copolyester resins exhibiting excellent solvent solubility and adhesiveness, and as adhesives using the same.
Further, in Patent Document 2, 25 to 100 mol% of 2,5-furandicarboxylic acid, 0 mol% to 75 mol% of aliphatic dicarboxylic acid having 4 to 36 carbon atoms, and 1 mol% to 10 mol% of a sulfonate group-containing compound. Aqueous polyester dispersions containing copolymerized polyester have been proposed.

WO2015/108026 Japanese Patent Publication No. 2020-502355

However, in the technique disclosed in Patent Document 1, in order to improve the adhesiveness as an adhesive, a certain amount or more of furandicarboxylic acid is contained, and the glass transition temperature is set to around room temperature to enhance the adhesiveness. When used as an adhesive, there was a problem that adhesive physical properties were insufficient.
In addition, the technique disclosed in Patent Document 2 above also contains a certain amount or more of furandicarboxylic acid and contains a sulfonate group-containing compound to improve water dispersibility, and the composition was not suitable as an adhesive. .

Therefore, in the present invention, under such a background, even when polycarboxylic acids having a furan skeleton are used, the adhesive physical properties to various adherends are good, and the adhesive physical properties such as adhesive strength and holding power are improved. An object of the present invention is to provide an excellent polyester-based resin composition, a pressure-sensitive adhesive composition, a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet and a double-sided pressure-sensitive adhesive sheet containing the same.

However, in the polyester resin composition, the present inventors have found that aliphatic and/or alicyclic polycarboxylic acids having 10 or more carbon atoms and polyvalent carboxylic acids having 10 or more carbon atoms and At least one compound of aliphatic and / or alicyclic polyols of 10 or more, and polyvalent carboxylic acids having a furan skeleton, aliphatic and / or alicyclic polyols having 10 or more carbon atoms in the polyester resin The amount of at least one compound of polyvalent carboxylic acids and aliphatic and/or alicyclic polyols having 10 or more carbon atoms is adjusted to the amount of polyvalent carboxylic acids having a furan skeleton at a molar concentration ratio of 0 The inventors have found that a pressure-sensitive adhesive having a viscosity of 0.6 or higher is environmentally friendly, has good adhesive physical properties to various adherends, and has excellent adhesive strength and holding power, and completed the present invention.

That is, the present invention has the following aspects [1] to [14].
[1] A polyester resin composition containing a polyester resin (A),
The polyester-based resin (A) is 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. (a1)-derived structural unit, further containing a structural unit derived from a polycarboxylic acid (a2) having a furan skeleton, the structure derived from the polycarboxylic acid (a2) in the polyester-based resin (A) A polyester resin composition wherein 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 unit is 0.6 or more.
[2] The polyester-based 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 a dimer acid and/or a dimer diol.
[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 polyester resin (A) has a number average molecular weight of 3000 or more.
[6] The polyester resin composition according to any one of [1] to [5], wherein the polyester resin (A) has a weight average molecular weight of 10,000 or more.
[7] The polyester resin composition according to any one of [1] to [6], wherein the polyester resin (A) has a glass transition temperature of -10°C or lower.
[8] The polyester resin composition according to any one of [1] to [7], wherein the polyester resin (A) has a biomass degree of 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 comprising a hydrolysis inhibitor (C).
[11] A pressure-sensitive adhesive composition containing the polyester resin composition according to any one of [1] to [10].
[12] A pressure-sensitive adhesive obtained by cross-linking the pressure-sensitive adhesive composition according to [11].
[13] A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive according to [12].
[14] A double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive according to [12].

The polyester-based resin composition of the present invention has a high degree of biomass and is a polyester-based resin composition that is friendly to the global environment. be.
Therefore, it can be effectively used as a single-sided or double-sided pressure-sensitive adhesive sheet for bonding optical members, a single-sided or double-sided pressure-sensitive adhesive sheet for fixing members of portable electronic devices, or for fixing electronic members.

The configuration of the present invention will be described in detail below, but these are examples of preferred embodiments.
In the present invention, the term "carboxylic acids" includes not only carboxylic acids but also carboxylic acid derivatives such as carboxylic acid salts, carboxylic acid anhydrides, carboxylic acid halides and carboxylic acid esters.
Further, in the present invention, "α and/or β (α and β are arbitrary constituents or components)" means three combinations of α only, β only, and α and β.

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

<Polyester resin (A)>
Polyester-based resins have, as their resin structures, structural units derived from polycarboxylic acids and structural units derived from polyols, and are usually obtained by polymerizing polymerization components containing polycarboxylic acids and polyols. .

The polyester resin (A) used in the present polyester resin composition contains a structural unit derived from the compound (a1) and a structural unit derived from polyvalent carboxylic acids (a2) having a furan skeleton. Such a polyester-based resin (A) is obtained by polymerizing a polymerizable component containing a compound (a1) and a polyvalent carboxylic acid (a2) having a furan skeleton.

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

[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, brassylic acids, and dimer acids. Among them, it is a plant-derived raw material, and from the viewpoint of availability and adhesive properties, sebacic acids or dimer acids are preferable, and dimer acids are more preferable.

The dimer acids are mainly composed of unsaturated fatty acid dimers having an average carbon number of 10 to 26, preferably unsaturated fatty acid dimers having an average carbon number of 12 to 24, more preferably average It is a dimer of unsaturated fatty acids with 14 to 22 carbon atoms. Specifically, for example, 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 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.

Examples of the dimer acids include dimer acids (mainly having 36 and 44 carbon atoms) derived from the unsaturated fatty acids, hydrogenated products of the above dimer acids, and the like. Among these, hydrogenated products of dimer acids are preferable because they tend to prevent crystallinity.

As raw materials for the dimer acids, plants, beef tallow, etc. are usually used. In the present invention, dimer acids derived from any raw materials can be used, but it is preferable to use plant-derived raw materials that are friendly to the global environment. . By using a plant-derived raw material, the biomass degree of the polyester-based resin (A), which will be described later, can be increased.

As a copolymerization component of the polyester resin (A), the content when using the above-mentioned aliphatic and / or alicyclic polycarboxylic acids having 10 or more carbon atoms is 10 to 100 with respect to the total polycarboxylic acids. It is preferably mol %, particularly preferably 20 to 99 mol %, more preferably 35 to 90 mol %, particularly preferably 51 to 80 mol %. If the content is too small, the polyester resin (A) tends to become too hard and the adhesive strength tends to decrease. If the content is too large, the adhesive tends to be too soft, resulting in a slight decrease in adhesive properties.

[Aliphatic and/or alicyclic polyol having 10 or more carbon atoms]
Examples of the aliphatic and/or alicyclic polyols having 10 or more carbon atoms include 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, dimer diall and the like. These may be used alone or in combination of two or more. Among them, 1,10-decanediol or dimer diol, which is a plant-derived raw material, is preferred in view of easy availability, and dimer diol is more preferred.

The above dimer diol is generally a diol derived from the above dimer acids. In the present invention, the dimer diol is preferably a plant-derived raw material, like the dimer acids.

When the aliphatic and/or alicyclic polyol having 10 or more carbon atoms is used as the copolymerization component of the polyester resin (A), the content thereof is 10 to 100 mol% based on the total polyol. It is preferably 20 to 99 mol %, more preferably 35 to 90 mol %, particularly preferably 51 to 80 mol %. If the content is too small, the adhesive properties tend to deteriorate. If the content is too large, the adhesive tends to be too soft, resulting in a slight decrease in adhesive properties.

[Polyvalent carboxylic acids having a furan skeleton (a2)]
The polyvalent carboxylic acid (a2) having a furan skeleton may be any polyvalent carboxylic acid having a furan skeleton in the structure of the compound, and examples thereof include 2,5-furandicarboxylic acids. These may be used alone or in combination of two or more.

The polyester-based resin (A) used in the present invention includes, in addition to the compound (a1) and polyvalent carboxylic acids (a2) having a furan skeleton, an aliphatic compound (a3) having 9 or less carbon atoms and an aromatic Compound (a4) may also be used.

[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.

(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 trivalent or higher polyvalent carboxylic acids.
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, and azelaic acids. Acyclic aliphatic dicarboxylic acids such as acids, fumaric acids, maleic acids, itaconic acids, thiodipropionic acids, diglycolic acids;
Alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acids, 1,2-cyclohexanedicarboxylic acids, 1,3-cyclohexanedicarboxylic acids, and 1,4-cyclohexanedicarboxylic acids are included.
These aliphatic polycarboxylic acids having 9 or less carbon atoms may be used alone or in combination of two or more.

In addition, as the aliphatic polycarboxylic acids having 9 or less carbon atoms, plant-derived aliphatic polycarboxylic acids are preferably used in order to increase the degree of biomass.
Examples of the plant-derived aliphatic polycarboxylic acids include corn-derived succinic acids.

(Aliphatic polyol having 9 or less carbon atoms)
Examples of the aliphatic polyols having 9 or less carbon atoms include divalent aliphatic diols and trihydric or higher aliphatic polyhydric alcohols.
Examples of the divalent aliphatic diol include 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, etc. Cycloaliphatic diols;
Alicyclic diols such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, isosorbide, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, etc. is mentioned.
Examples of the trihydric or higher aliphatic polyhydric alcohol include pentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,3, and 6-hexanetriol.
These aliphatic polyols having 9 or less carbon atoms may be used alone or in combination of two or more.

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 less carbon atoms in the polyol. More preferred are acyclic aliphatic diols having 2 to 9 carbon atoms, and particularly preferred are 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-based resin (A) and provide more excellent adhesiveness.

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

For the aliphatic polyol having 9 or less carbon atoms, it is preferable to use a plant-derived polyol in order to increase the degree of biomass.
Examples of the plant-derived polyols include isosorbide, fatty acid ester-based diols derived from castor oil, bioethylene glycol, bio-1,3-propane glycol, and biobutylene glycol. Among them, bioethylene glycol is preferred.

Moreover, polyethylene terephthalate may be used as the acyclic aliphatic diol having 9 or less carbon atoms. The polyethylene terephthalate is a polyester resin obtained by polymerizing terephthalic acid and ethylene glycol. Therefore, by using polyethylene terephthalate, the polyester-based resin (A) has an ethylene glycol-derived structural unit derived from polyethylene terephthalate as a structural unit derived from an acyclic aliphatic diol having 9 or less carbon atoms. Moreover, 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.

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, as an aliphatic polyol having 9 or less carbon atoms, a trivalent or higher aliphatic Group polyhydric alcohols are preferably used, such as trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,2,6-hexane Triols can be used. Among these, it is particularly preferable to use trimethylolpropane because gels are relatively unlikely to occur.

The content of such a trihydric or higher aliphatic polyhydric alcohol is preferably 20 mol% or less, more preferably 0.1 to 10 mol%, particularly 0, based on the total polyol. 0.5 to 5 mol % is preferred. 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).

In addition, it is preferable to use a plant-derived aliphatic polyol having 9 or less carbon atoms. Polyols may also be used. However, even in that case, in order to increase the degree of biomass, it is preferable to use a linear acyclic aliphatic diol having 4 or less carbon atoms, particularly a linear acyclic aliphatic diol having 2 to 3 carbon atoms. Preference is given to using diols. Examples of straight-chain acyclic aliphatic diols having 4 or less carbon atoms include ethylene glycol, 1,3-propanediol, and 1,4-butanediol. That is, when an aliphatic polyol having 9 or less carbon atoms and having a small carbon number of 4 or less is used, the weight ratio of carboxylic acids with a high biomass degree as the polyester resin (A) increases, and the biomass degree is increased. This is because

[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, aromatic polycarboxylic acids are preferably used as the aromatic compound (a4) because of their excellent adhesive strength and holding power.

(Aromatic Polycarboxylic Acids)
Examples of the aromatic polycarboxylic acids include divalent aromatic dicarboxylic acids and trivalent or higher aromatic polyvalent carboxylic acids, and aromatic dicarboxylic acids are preferably used from the viewpoint of stably obtaining polyester resins. be done.

Examples of the aromatic dicarboxylic acids include phthalic acids, terephthalic acids, isophthalic acids, benzylmalonic acids, diphenic acids, 4,4′-oxydibenzoic acids, 1,8-naphthalenedicarboxylic acids, and 2,3-naphthalenedicarboxylic acids. , Benzene aromatic dicarboxylic acids such as naphthalenedicarboxylic acids such as 2,7-naphthalenedicarboxylic acids; mentioned. These may be used alone or in combination of two or more. Among them, terephthalic acids and isophthalic acids are preferable because of their easy availability.

Examples of the trivalent or higher aromatic polyvalent carboxylic acids include trimellitic acids, pyromellitic acids, and trimesic acids. These may be used alone or in combination of two or more.

It is also preferable to use polyethylene terephthalate as the aromatic polycarboxylic acid. As described above, polyethylene terephthalate is a polyester resin in which terephthalic acids and ethylene glycol are polymerized. By using the polyethylene terephthalate, the polyester-based resin (A) will have a structural unit derived from the terephthalic acid derived from the polyethylene terephthalate as the structural unit derived from the aromatic polycarboxylic acid.
The polyethylene terephthalate is optionally modified with substances such as isophthalic acids, phthalic anhydrides, adipic acids, cyclohexanedicarboxylic acids, sebacic acids, 1,3-butanediol, 1,4-butanediol, and cyclohexanedimethanol. It may also be a Moreover, 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.

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

[Production of polyester resin (A)]
In the present invention, the polyester-based 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. , or after the transesterification reaction is carried out, the polycondensation reaction is carried out. In addition, when it is not necessary to increase the molecular weight, it may be produced only by esterification reaction or transesterification reaction.

In such an esterification reaction or transesterification reaction, a catalyst is used. Specifically, examples include titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate, antimony-based catalysts such as antimony trioxide, and germanium dioxide. Catalysts such as germanium-based catalysts and catalysts such as zinc acetate, manganese acetate, and dibutyltin oxide can be used, and one or more of these can be used. Among these, antimony trioxide, tetrabutyl titanate, germanium dioxide, and zinc acetate are preferable from the viewpoint of the balance between the high catalytic activity and the hue of the reaction product obtained.

The blending amount of the above catalyst is preferably 1 to 10000 ppm, particularly preferably 10 to 5000 ppm, more preferably 20 to 3000 ppm based on the total copolymerization components (weight basis). If the compounding amount is too small, the polymerization reaction tends to be difficult to proceed sufficiently, and if it is too large, there is no advantage in shortening the reaction time, etc., and side reactions tend to occur easily.

The reaction temperature during the esterification reaction is preferably 200 to 300°C, particularly preferably 210 to 280°C, further preferably 220 to 260°C. If the 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. Moreover, the pressure during the reaction is usually normal pressure.

As the reaction conditions for the polycondensation reaction to be performed after the esterification reaction or the transesterification reaction, the same catalyst as used in the esterification reaction or the transesterification reaction is blended in the same amount. Preferably, the reaction temperature is set to 200 to 280° C., particularly preferably 210 to 270° C., and the reaction system is gradually decompressed to finally carry out the reaction at 5 hPa or less. If the 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.

Thus, a polyester-based resin (A) containing structural units derived from the compound (a1) and structural units derived from the polycarboxylic acid (a2) having a furan skeleton is obtained.

In the polyester resin (A), from the viewpoint of excellent adhesive strength and holding power, the molar concentration (X2) of the structural unit derived from polyvalent carboxylic acids (a2) having a furan skeleton in the polyester resin (A) , the ratio (X1/X2) of the molar concentration (X1) of the structural unit derived from the compound (a1) must be 0.6 or more. It is preferably 1.0 or more, more preferably 1.5 or more, still more preferably 2.0 or more, and particularly preferably 2.5 or more. When (X1/X2) is less than the above numerical value, adhesive strength and holding power are lowered. Also, the upper limit of (X1/X2) is usually 20, preferably 10, more preferably 6.0, still more preferably 5.0, particularly preferably 4.0, particularly preferably 3.5.

The number average molecular weight of the 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, particularly preferably 6,000 to 20,000, Most preferably 7000-15000. If the number-average molecular weight is too large, the handling properties will deteriorate, so a large amount of solvent will be required, and the environmental load will tend to increase.

The weight average molecular weight of the 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, particularly preferably 40,000 to 200,000, and most preferably 40,000 to 200,000. It is preferably 50,000 to 150,000. If the weight average molecular weight is too small, adhesive physical properties tend to deteriorate. If the weight-average molecular weight is too large, the handling property is deteriorated, so a large amount of solvent is required, which tends to increase the environmental load.

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. (exclusion limit molecular weight: 2×10 ⁶ , number of theoretical plates: 16,000 plates/line, filler material: styrene-divinylbenzene copolymer, filler particle size: 4 μm) are used in series. is.

Further, the biomass degree of the polyester resin (A) is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, particularly preferably 85%. above, and most preferably above 90%. Note that the upper limit is 100%. If the degree of biomass is low, the environmental load tends to be insufficiently reduced.

Here, the biomass degree of the polyester resin (A) means that the plant-derived raw materials used for producing the polyester resin (A) are incorporated into the resin with respect to the total weight of the polyester resin (A). It is the weight ratio of the part that has been removed, and the calculation method is as follows.
The biomass degree of polyvalent carboxylic acids and polyols is obtained from the weighted average of the respective biomass degrees.
Moreover, the value obtained by any one of the following calculation methods may be within the above range.

(Method of calculation)
<Case involving polycondensation reaction>
Biomass degree (%) = [(number of moles of carbon in plant-derived monomers calculated from the molar ratio of polycarboxylic acids and polyols in polyester resin (A)) / (total constituent monomers in polyester resin (A) number of moles of carbon)] × 100

<Case without polycondensation reaction>
Biomass degree (%) = [(number of moles of carbon in plant-derived monomer in polyester resin (A)) / (number of moles of carbon in all constituent monomers in polyester resin (A))] × 100

The biomass content can also be obtained by analyzing the composition ratio by NMR and calculating the carbon number of the plant-derived monomer/the total carbon number.

Furthermore, the above biomass degree can also be measured by the method described in Tokyo Metropolitan Industrial Technology Research Center Research Report, No. 4, 2009, "Technology for determining the origin of biofuel using natural radioactive carbon C-14". .

As a method for adjusting the biomass degree to a predetermined range, plant-derived polycarboxylic acids and plant-derived polyols are mainly used. It is preferable that the polyvalent carboxylic acids are derived from plants.

The glass transition temperature (Tg) of the polyester resin (A) is preferably −10° C. or less, more preferably −90 to −10° C., particularly preferably −60 to −20° C., and further It is preferably -50 to -30°C, particularly preferably -45 to -35°C. If the glass transition temperature (Tg) is too high, the adhesion of the pressure-sensitive adhesive tends to decrease, and if it is too low, heat resistance tends to decrease and cohesive force tends to decrease.

The 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 rise rate is 10°C/min.

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, particularly preferably 4.2 to 5 mmol/g. in millimoles/g. If the ester group concentration is too low, the polyester-based resin (A) will become soft, and the adhesive properties will tend to be lowered due to the excessive softness.

The above-mentioned ester group concentration (mmol/g) means the number of moles of ester bonds in 1 g of the polyester resin (A), and is determined, for example, by a calculated value from the charged amount. This calculation method is a value obtained by dividing the number of moles of the carboxylic acid and the polyol, whichever is the smaller amount charged, by the total weight, and an example of the calculation formula is shown below.
When the amounts of the polycarboxylic acids and the polyol charged are the same molar amount, either of the following formulas may be used.
Moreover, when using a monomer having both a carboxyl group and a hydroxyl group, or when producing a polyester from caprolactone or the like, the calculation method is appropriately changed.

<When the amount of polycarboxylic acids 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 charged
x1, x2, x3...: molecular weight of polyvalent carboxylic acid m1, m2, m3...: number of carboxy groups per molecule of polyvalent carboxylic acid Z: finished weight (g)
<When polyol is less>
Ester group concentration (mmol/g) = [(Y1/y1 x n1 + Y2/y2 x n2 + Y3/y3 x n3 ...)/Z] x 1000
Y1, Y2, Y3 . . . : Charged amount of polyol (g)
y1, y2, y3...: Molecular weight of polyol n1, n2, n3...: Number of hydroxyl groups per molecule of polyol Z: Finished weight (g)

The 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) can be determined by ¹ H-NMR measurement (proton type nuclear magnetic resonance spectroscopy) and ¹³ C-NMR measurement (carbon type nuclear magnetic resonance spectroscopy) at a resonance frequency of 400 MHz. can be done.

Examples of the method for adjusting the ester group concentration include 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 polyvalent carboxylic acid, a method of combining both, and the like. mentioned.

The heat of crystal fusion of the polyester resin (A) measured with a differential scanning calorimeter is usually 10 J/g or less, preferably 5 J/g or less, more preferably 2 J/g or less, and particularly preferably the heat of crystal fusion is It is not to come out. If the heat of fusion of crystals is too large, crystallinity will appear, and the storage stability of the resin solution will tend to decrease, and the low-temperature stability and adhesive properties when made into a pressure-sensitive adhesive sheet will tend to decrease.
The heat of crystal fusion is the energy consumed when heating and melting a crystallized substance, and can be measured by a differential scanning calorimeter DSC.

As a method for adjusting the heat of fusion of crystals, for example, 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, or a method of using three or more copolymer monomer components, preferably is a method of using four or more components, and the like.

The acid value of the polyester resin (A) is preferably 10 mgKOH/g or less in terms of preventing hydrolysis and increasing durability, more preferably 5 mgKOH/g or less, and particularly preferably 2 mgKOH/g or less. . If the acid value is too high, the durability tends to decrease.
To adjust the acid value, for example, the proportion of polyol is increased during the esterification reaction or the transesterification reaction, or the reaction conditions are adjusted. Incidentally, the lower limit of the acid value is usually 0 mgKOH/g.

The acid value of the polyester resin (A) is obtained by neutralization titration based on JIS K0070.
The acid value in the present invention means the content of carboxy groups in the polyester resin (A). The above carboxyl group also includes carboxylate ions in which the carboxyl group is neutralized with a basic compound.

The content of the polyester resin (A) in the present polyester resin composition 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 properties. .

In the present polyester resin composition, along with the polyester resin (A), a polyvalent isocyanate compound (B), a hydrolysis inhibitor (C), and, if necessary, a tackifier (D), a urethanization catalyst It is preferable to contain (E), an antioxidant (F), and the like.

<Polyvalent isocyanate compound (B)>
The present polyester resin composition preferably further contains a polyvalent isocyanate compound (B) as a cross-linking agent. By containing the polyvalent isocyanate compound (B), the polyester resin (A) is It is crosslinked with the isocyanate compound (B) and has excellent cohesive strength, thus improving the performance as a pressure-sensitive adhesive.

Examples of such polyvalent isocyanate compounds (B) include tolylene diisocyanate-based cross-linking agents such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, and xylylene diisocyanates such as 1,3-xylylene diisocyanate. Aromatic isocyanate-based cross-linking agents such as diphenylmethane-based cross-linking agents such as diphenylmethane-4,4-diisocyanate and naphthalene diisocyanate-based cross-linking agents such as 1,5-naphthalenediisocyanate; isophorone diisocyanate and 1,4-cyclohexane diisocyanate , 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, 1,3-diisocyanatomethylcyclohexane, norbornane diisocyanate and other alicyclic isocyanate cross-linking agents; hexamethylene Aliphatic isocyanate-based cross-linking agents such as diisocyanate and trimethylhexamethylene diisocyanate; and adducts of the above isocyanate-based compounds and polyol compounds such as trimethylolpropane, and burettes and isocyanurates of these isocyanate-based compounds. . As the polyvalent isocyanate-based compound (B), those whose isocyanate moieties are blocked with phenol, lactam, or the like can also be used. These polyvalent isocyanate compounds (B) may be used singly or in combination of two or more.

When such a polyvalent isocyanate compound (B) is used, its content can be appropriately selected depending on the molecular weight of the polyester resin (A) and the purpose of use. Reactive groups contained in the polyvalent isocyanate compound (B) contain the polyvalent isocyanate compound (B) at a ratio of 0.2 to 10 equivalents with respect to 1 equivalent of at least one of the groups. It is preferably 0.5 to 5 equivalents, more preferably 0.5 to 3 equivalents. If the number of equivalents of the reactive groups contained in the polyvalent isocyanate compound (B) is too small, the cohesive strength tends to decrease, and if it is too large, the flexibility tends to decrease.

Further, in the reaction between the polyester resin (A) and the polyvalent isocyanate compound (B), an organic solvent that does not have a functional group that reacts with these polyester resin (A) and polyvalent isocyanate compound (B) components For example, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and organic solvents such as aromatics such as toluene and xylene can be used. These can be used alone or in combination of two or more.

<Hydrolysis inhibitor (C)>
The hydrolysis inhibitor (C) is contained as necessary in order to secure the long-term durability of the polyester-based resin composition.
As the hydrolysis inhibitor (C), conventionally known ones can be used, and examples thereof include compounds that react with and bind to the terminal carboxy group of the polyester resin (A). Specific examples include compounds containing functional groups such as carbodiimide groups, epoxy groups, oxazoline groups, and the like. Among these, carbodiimide group-containing compounds are preferred because they are highly effective in eliminating the catalytic activity of protons derived from the terminal carboxyl group.

As the carbodiimide group-containing compound, a known carbodiimide having one or more carbodiimide groups (-N=C=N-) in the molecule may be used, but the durability under high temperature and high humidity is improved. is preferably a compound containing two or more carbodiimide groups in the molecule, i.e., a polyvalent carbodiimide compound, in particular three or more carbodiimide groups in the molecule, further five or more, especially seven or more. It is preferably a compound containing The number of carbodiimide groups in the molecule is usually 50 or less, and if there are too many carbodiimide groups, the molecular structure becomes too large, which tends to reduce compatibility. It is also preferable to use a high-molecular-weight polycarbodiimide produced by a decarboxylation condensation reaction of a diisocyanate in the presence of a carbodiimidation catalyst.

Further, the high-molecular-weight polycarbodiimide whose terminal isocyanate groups are blocked with a blocking agent is preferable from the viewpoint of storage stability. Examples of blocking agents include compounds having active hydrogens that react with isocyanate groups, or compounds having isocyanate groups. Examples thereof include monoalcohols, monocarboxylic acids, monoamines, and monoisocyanates having one substituent selected from a carboxy group, an amino group, and an isocyanate group.

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

Such diisocyanates include, for example, 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 and the like can be mentioned, and 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.

Commercially available products of the carbodiimide group-containing compound include, for example, the Carbodilite (registered trademark) series manufactured by Nisshinbo Chemical Co., Ltd. Among them, Carbodilite (registered trademark) “V-01”, “V-02B”, "V-03", "V-04K", "V-04PF", "V-05", "V-07", "V-09" and "V-09GB" have excellent compatibility with organic solvents. point is preferable.

Preferred examples of the epoxy group-containing compound include glycidyl ester compounds and glycidyl ether compounds.

Specific examples of the glycidyl ester compounds include glycidyl benzoate, glycidyl t-butylbenzoate, glycidyl p-toluate, glycidyl cyclohexanecarboxylate, glycidyl pelargonate, glycyl stearate, and lauric acid. Glycidyl ester, glycidyl palmitate, glycidyl behenate, glycidyl versatate, glycidyl oleate, glycidyl linoleate, glycidyl linolenate, glycidyl behenoleate, glycidyl stearate, diglycidyl terephthalate, Diglycidyl isophthalate, diglycidyl phthalate, diglycidyl naphthalene dicarboxylate, diglycidyl methyl terephthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, diglycidyl cyclohexanedicarboxylate, adipic acid diglycidyl ester, diglycidyl succinate, diglycidyl sebacate, diglycidyl dodecanedioate, diglycidyl octadecanedicarboxylate, triglycidyl trimellitate, tetraglycidyl pyromellitic acid, and the like. They can be used alone or in combination of two or more.

Specific examples of the glycidyl ether compounds include phenylglycidyl ether, o-phenylglycidyl 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-[р-(β,γ-epoxypropoxy)phenyl]propane and 2,2-bis-(4-hydroxyphenyl)propane and 2,2-bis-(4-hydroxyphenyl ) bisglycidyl polyether obtained by reaction of bisphenol such as methane and epichlorohydrin, and the like, and these can be used alone or in combination of two or more.

A bisoxazoline compound or the like is preferable as the oxazoline group-containing compound. 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-phenylenebis(2-oxazoline), 2 , 2′-m-phenylenebis(2-oxazoline), 2,2′-o-phenylenebis(2-oxazoline), 2,2′-p-phenylenebis(4-methyl-2-oxazoline), 2, 2′-p-phenylenebis(4,4-dimethyl-2-oxazoline), 2,2′-m-phenylenebis(4-methyl-2-oxazoline), 2,2′-m-phenylenebis(4, 4-dimethyl-2-oxazoline), 2,2′-ethylenebis(2-oxazoline), 2,2′-tetramethylenebis(2-oxazoline), 2,2′-hexamethylenebis(2-oxazoline), 2,2'-octamethylenebis(2-oxazoline), 2,2'-decamethylenebis(2-oxazoline), 2,2'-ethylenebis(4-methyl-2-oxazoline), 2,2'- Tetramethylenebis(4,4-dimethyl-2-oxazoline), 2,2'-9,9'-diphenoxyethanebis(2-oxazoline), 2,2'-cyclohexylenebis(2-oxazoline), 2 , 2'-diphenylene bis(2-oxazoline) and the like can be exemplified. Most preferred from Moreover, these can be used individually or in combination of 2 or more types.

As these hydrolysis inhibitors (C), those having low volatility are preferable, and therefore those having a high number average molecular weight are preferably used, usually 300 to 10,000, preferably 1,000 to 5,000.
As the hydrolysis inhibitor (C), it is preferable to use one having a high weight-average molecular weight from the viewpoint of hydrolysis resistance. 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. In addition, 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, when the molecular weight is too large, the compatibility with the polyester resin (A) tends to decrease.

Among the hydrolysis inhibitors (C), it is preferable to use a carbodiimide group-containing compound, in which case the carbodiimide equivalent is preferably 50 to 10000, particularly 100 to 1000, and further 150 to 500. is preferred. The carbodiimide equivalent is the chemical formula weight per carbodiimide group.

When the hydrolysis inhibitor (C) is used, its content is preferably 0.01 to 10 parts by weight, particularly preferably 0.1, with respect to 100 parts by weight of the polyester resin (A). to 5 parts by weight, more preferably 0.2 to 3 parts by weight. If the content is too large, turbidity tends to occur due to poor compatibility with the polyester resin (A), and if it is too small, it tends to be difficult to obtain sufficient durability.

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

<Tackifier (D)>
In the present polyester-based resin composition, it is preferable to contain a tackifier (D) in order to improve the adhesive properties.

The tackifier (D) is not particularly limited, and conventionally known ones can be used. Examples of the tackifier (D) include hydrocarbon-based tackifier resins, terpene-based resins, phenol-based resins, rosin-based resins, xylene resins, epoxy-based resins, polyamide-based resins, ketone-based resins, elastomer-based resins, and the like. mentioned. These may be used alone or in combination of two or more. Among them, hydrocarbon-based tackifying resins and terpene-based resins are preferable. In addition, it is particularly preferable that the tackifier (D) contains at least one hydrocarbon-based tackifier resin, and the hydrocarbon-based tackifier resin accounts for 30% by weight or more of the total tackifier. It is preferably 50% by weight or more, preferably 70% by weight or more.

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

Examples of the terpene-based resins include terpene resins, terpene phenolic resins, and aromatic modified terpene resins. Specific examples include α-pinene polymer, β-pinene polymer, dipentene polymer, Phenol-modified, aromatic-modified, hydrogenated-modified, and hydrocarbon-modified terpene-based resins can be used. In addition, commercially available products include, for example, "YS Polyster S145", "YS Resin PX1000", "YS Resin PX1250", "YS Polyster T160", "YS Polyster T145", "YS Polyster T130", "YS Polyster T130" manufactured by Yasuhara Chemical Co., Ltd. YS Resin TO115", "YS Polyster G150", "YS Polyster G125", "YS Polyster U130", "Clearon P125", etc., and terpene in that it has good adhesion to non-polar adherends such as polypropylene. based resins are preferred.

Examples of the phenolic resin include condensates of various phenols such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol and resorcinol with formaldehyde. Furthermore, resoles obtained by addition reaction of the phenols and formaldehyde in the presence of an alkali catalyst, novolacs obtained by the condensation reaction of the phenols and formaldehyde in the presence of acid catalysts, unmodified or modified rosins, and these A rosin-modified phenol resin obtained by adding phenol to a rosin such as a derivative thereof in the presence of an acid catalyst and thermally polymerizing the resin can be used.

Examples of the rosin-based resin include rosin resin, polymerized rosin resin, hydrogenated rosin resin, rosin ester resin, hydrogenated rosin ester resin, rosin phenol resin, polymerized rosin ester, etc. Specifically, gum rosin, Unmodified rosins (fresh rosins) such as wood rosin and tall oil rosin, modified rosins obtained by hydrogenation, disproportionation, polymerization or other chemical modifications, and derivatives thereof can be used. Commercially available products include, for example, Harima Kasei Co., Ltd.'s "Harryester TF", "Haritac 8LJA", "Haritac PH", "Haritac FK100", and "Haritac PCJ".

The tackifier (D) preferably has an acid value of 30 mgKOH/g or less, more preferably 10 mgKOH/g or less, more 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 is preferably within the above range.

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

In the present polyester-based resin composition, the tackifier (D) is preferably derived from plants in order to keep the biomass degree of the entire polyester-based resin composition high. Plant-derived tackifiers include, for example, terpene-based resins and rosin-based resins.

The tackifier (D) preferably contains an aromatic structural unit from the viewpoint of cohesive strength improvement and compatibility. Examples of tackifiers containing aromatic structural units include aromatic hydrocarbon resins, aliphatic/aromatic petroleum resins (styrene-olefin copolymers, etc.), coumarone resins, coumarone-indene resins, Terpene phenol resins and aromatic modified terpene resins can be mentioned.

When the tackifier (D) is used, its content is preferably 2 to 200 parts by weight, more preferably 5 to 150 parts by weight, with respect to 100 parts by weight of the polyester resin (A). , 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. When the content is within the above range, there is a tendency that adhesive properties (adhesive strength, cohesive strength) can be improved.

<Urethane catalyst (E)>
This adhesive composition more preferably contains a urethanization catalyst (E) in terms of reaction speed.

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.

Examples of the organometallic compounds include zirconium-based compounds, iron-based compounds, tin-based compounds, titanium-based compounds, lead-based compounds, cobalt-based compounds, and zinc-based compounds.

Examples of the zirconium-based 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-based compound include dibutyltitanium dichloride, tetrabutyltitanate, butoxytitanium trichloride, and the like.
Examples of the lead-based compound include lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate.
Examples of the cobalt-based compound include cobalt 2-ethylhexanoate and cobalt benzoate.
Examples of the zinc-based compound include zinc naphthenate and zinc 2-ethylhexanoate.

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

Among these urethanization catalysts (E), organometallic compounds are preferred, and zirconium compounds are particularly preferred, in terms of reaction rate and pot life of the pressure-sensitive adhesive layer. Further, the urethanization catalyst (E) is preferably used together with acetylacetone as a catalytic action inhibitor. Containing acetylacetone is preferable in terms of suppressing the catalytic action at low temperatures and prolonging the pot life.

When the urethanization catalyst (E) is used, its content is preferably 0.0001 to 1 part by weight, particularly 0.001 to 0.1 part by weight, based on 100 parts by weight of the polyester resin (A). parts by weight, more preferably 0.01 to 0.05 parts by weight. If the content is too small, the aging time until the completion of the cross-linking reaction tends to become long, and if it is too large, the adhesive properties tend to decrease.

<Antioxidant (F)>
The present polyester resin composition more preferably contains an antioxidant (F) from the viewpoint of increasing the stability of the resin.

Examples of the antioxidant (F) include hindered phenol-based antioxidants, amine-based antioxidants, sulfur-based antioxidants, and phosphoric acid-based antioxidants. These may be used alone or in combination of two or more. Among them, at least one selected from hindered phenol antioxidants, amine antioxidants and phosphoric acid antioxidants is preferred, and antioxidants comprising hindered phenol compounds are particularly preferred.
Hindered phenolic antioxidants include, for example, hindered phenolic antioxidants in which at least one of the carbon atoms adjacent to the carbon atoms on the aromatic ring to which the hydroxyl group of phenol is bonded is bonded with a group having large steric hindrance such as a tertiary butyl group. An antioxidant having a phenol structure is mentioned.

When the antioxidant (F) is used, its content is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 8 parts by weight, relative to 100 parts by weight of the polyester resin (A). and more preferably 0.05 to 5 parts by weight.
If the content is too small, adhesive residue tends to be easily generated on the adherend, and if the content is too large, adhesive physical properties tend to deteriorate.

In the present polyester resin composition, the above polyester resin (A), polyvalent isocyanate compound (B), hydrolysis inhibitor (C), tackifier (D), urethanization catalyst (E), In addition to the antioxidant (F), additives such as softeners, ultraviolet absorbers, stabilizers, antistatic agents, etc., inorganic or organic fillers, metals, etc. Powders, powders such as pigments, and particulate additives can be blended. Further, it may contain a small amount of impurities contained in raw materials for manufacturing the constituent components of the polyester-based pressure-sensitive adhesive composition.
These can be used alone or in combination of two or more.

Such a present polyester-based resin composition is prepared, for example, by preparing the polyester-based resin (A) and optional components as necessary, and blending and dispersing them during the production of the polyester-based resin (A), or It can be obtained by blending it with a solution of the polyester resin (A) dissolved in an organic solvent and dispersing it using a mixing roller.

The present polyester-based resin composition preferably has a biomass degree of 50% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, particularly preferably 80% or more, in terms of reducing environmental load. is 85% or more, most preferably 90% or more. The biomass degree of the pressure-sensitive adhesive can be adjusted by adjusting the types and amounts of the polyester resin (A) and other compounding components.
The biomass degree of the polyester resin composition is the ratio of the weight of the plant-derived raw material used in producing the polyester resin composition to the total weight of the polyester resin composition. can ask.
Biomass degree (%) = [(biomass degree of each plant-derived raw material used when producing the polyester resin composition) × (weight of each plant-derived raw material used when producing the polyester resin composition )] / (Total weight of polyester resin composition)

The biomass content of the polyester-based resin composition can also be measured by the above-described method using NMR or the method using natural radioactive carbon C-14. Note that the value obtained by any one of the above calculation methods may be within the above range.

A pressure-sensitive adhesive composition (hereinafter referred to as "the present pressure-sensitive adhesive composition") which is one embodiment of the present invention contains the present polyester-based resin composition, and preferably consists of the present polyester-based resin composition. It is.
Moreover, the pressure-sensitive adhesive (hereinafter referred to as "the present pressure-sensitive adhesive") that is one embodiment of the present invention is obtained by cross-linking the above-mentioned present pressure-sensitive adhesive composition.

A pressure-sensitive adhesive sheet (hereinafter referred to as "the present pressure-sensitive adhesive sheet") that is one embodiment of the present invention has a pressure-sensitive adhesive layer containing the present pressure-sensitive adhesive, and the pressure-sensitive adhesive layer is a support substrate. It is preferably formed on one side or both sides.
In the present invention, the term "sheet" includes "film" and "tape".

<Adhesive sheet>
The pressure-sensitive adhesive sheet can be produced, for example, as follows.
As a method for producing such a pressure-sensitive adhesive sheet, it can be produced according to a known general pressure-sensitive adhesive sheet production method. A release sheet is attached to the base material, and if necessary, curing is performed to obtain the present pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive on the base material.

Alternatively, the present pressure-sensitive adhesive sheet can be obtained by coating the present pressure-sensitive adhesive composition on a release sheet, drying it, bonding a substrate to the opposite side of the pressure-sensitive adhesive layer, and curing if necessary.

Also, a substrate-less double-sided PSA sheet can be produced by forming a PSA layer on a release sheet and laminating the release sheet on the opposite side of the PSA layer.

When using the obtained pressure-sensitive adhesive sheet or substrate-less double-sided pressure-sensitive adhesive sheet, the release sheet is peeled off from the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer and the adherend are bonded together.

Examples of the base material include polyester resins such as polyethylene naphtate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate/isophthalate copolymer; polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; polyvinyl fluoride; Polyethylene fluoride resins such as polyvinylidene fluoride and polyethylene fluoride; polyamides such as nylon 6 and nylon 6,6; polyvinyl chloride, polyvinyl chloride/vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl Vinyl polymers such as alcohol copolymers, polyvinyl alcohol and vinylon; Cellulose resins such as cellulose triacetate and cellophane; Acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate and polybutyl acrylate. polystyrene; polycarbonate; polyarylate; polyimide; sheet made of at least one kind of synthetic resin selected from the group consisting of cycloolefin polymers; metal foils of aluminum, copper and iron; Textiles and non-woven fabrics made of fibers, natural fibers, synthetic fibers and the like can be mentioned. These substrates can be used as a single-layer body or as a multi-layer body in which two or more types are laminated.

Among these, substrates made of polyethylene terephthalate and polyimide are particularly preferred, and polyethylene terephthalate is particularly preferred because of its excellent adhesiveness to pressure-sensitive adhesives.

Further, as the base material, a foam base material, for example, a foam sheet made of synthetic resin foam such as polyurethane foam, polyethylene foam, polyacrylate foam, or the like can be used. Among these, polyethylene foams and polyacrylate foams are preferred from the viewpoint of excellent balance between conformability to adherends and adhesive strength.

The thickness of the substrate is, for example, preferably 1 to 1000 μm, particularly preferably 2 to 500 μm, further preferably 3 to 300 μm.

As the release sheet, for example, a release-treated sheet, paper, cloth, non-woven fabric, or the like made of the various synthetic resins exemplified in the base material can be used. As the release sheet, it is preferable to use a silicon-based release sheet.

As the coating method of the pressure-sensitive adhesive composition, for example, a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, comma coater and the like may be used.

The conditions for the curing treatment are usually room temperature (23° C.) to 70° C., and the time is usually 1 to 30 days. It may be carried out under conditions such as up to 14 days and 1 to 10 days at 40°C.

As 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.

The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet and the substrate-less double-sided pressure-sensitive adhesive sheet is preferably 2 to 500 μm, particularly preferably 5 to 200 μm, further preferably 10 to 100 μm. If the thickness of the pressure-sensitive adhesive layer is too thin, the adhesive strength tends to decrease. be. In addition, it is preferable to make it 50 micrometers or more when considering impact absorption.

The thickness of the pressure-sensitive adhesive layer is obtained by subtracting the thickness of the constituent members other than the pressure-sensitive adhesive layer from the measured thickness of the entire pressure-sensitive adhesive sheet using "ID-C112B" manufactured by Mitutoyo. .

The gel fraction of the adhesive layer of the adhesive sheet is preferably 10% by weight or more, particularly preferably 20 to 80% by weight, more preferably 30 to 70% by weight, from the viewpoint of durability and adhesive strength. be. If the gel fraction is too low, there is a tendency for the holding power to decrease due to a decrease in the cohesive force. In addition, when the gel fraction is too high, there is a tendency that the cohesion increases and the adhesive strength decreases.

The gel fraction is a measure of the degree of cross-linking, and is calculated, for example, by the following method. That is, an adhesive sheet (without a release sheet) in which an adhesive layer is formed on a polymer sheet (for example, PET film, etc.) serving as a base material is wrapped in a 200-mesh SUS wire mesh, and then placed in toluene. It is immersed at 23° C. for 24 hours, and the weight percentage of the undissolved adhesive component remaining in the wire mesh after immersion with respect to the weight of the adhesive component before immersion is defined as the gel fraction. However, the weight of the base material is subtracted.

Furthermore, this pressure-sensitive adhesive sheet may be protected by providing a release sheet outside the pressure-sensitive adhesive layer, if necessary. Further, in a pressure-sensitive adhesive sheet in which an adhesive layer is formed on one side of a base material, the surface of the base material opposite to the pressure-sensitive adhesive layer is subjected to a release treatment so that the pressure-sensitive adhesive layer can be removed using the release-treated surface. can also be protected.

The present pressure-sensitive adhesive can be used for bonding various members, and in particular, a single-sided or double-sided pressure-sensitive adhesive sheet used for bonding optical members, a single-sided or double-sided adhesive sheet for fixing members of portable electronic devices, and for fixing electronic members Used for adhesive sheets, etc.

EXAMPLES 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 addition, "parts" and "%" in the examples mean weight standards.

Further, the biomass degree of the polyester resin, the recycled carbon usage rate, the weight average molecular weight, the glass transition temperature, the gel fraction of the adhesive layer, the biomass degree of the polyester resin composition, and the recycled carbon usage rate in the following examples Regarding the measurement, it was measured according to the method described above.

A polyester resin was produced by the following method (see Table 1).

[Examples 1 to 5, Comparative Examples 1 to 3]
[Production of polyester resin (A) [A-1 to A-5] and (A') [A'-1 to A'-3]]
A reaction vessel equipped with a thermometer, a stirrer, a rectifying column, a nitrogen inlet tube and a vacuum device was blended with polyvalent carboxylic acids and polyols as shown in Table 1 below, and tetrabutyl titanate was added as a catalyst. 0.2 mmol/mol was charged with respect to carboxylic acids, and the internal temperature was gradually raised to 240 to 250° C., and the esterification reaction was carried out over 4 hours. Then, the internal temperature is raised to 260° C., tetrabutyl titanate is charged as a catalyst at 0.2 mmol/mol with respect to polyvalent carboxylic acids, the pressure is reduced to 1.33 to 2.66 hPa, and the polymerization reaction is carried out over 2 to 3 hours. to produce a polyester resin (A) or (A').
The composition ratio, physical properties, etc. of the obtained polyester resin (A) or (A') were as shown in Table 2 below.
In the above production, plant-derived raw materials were hydrogenated distillation dimer acid, 2,5-furandicarboxylic acid, and sebacic acid.

Next, prior to preparing the polyester-based resin composition (adhesive composition), each component was prepared as follows.

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

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

[Examples 1-1 to 5-1, Comparative Examples 1-1 to 3-1]
Using the above polyester resin, cross-linking agent, and hydrolysis inhibitor, a polyester resin composition (adhesive composition) was prepared as follows with the formulation shown in Table 3 below, and a pressure-sensitive adhesive sheet was produced. .

The polyester resin [(A) or (A')] obtained above was diluted with ethyl acetate to a solid content concentration of 50%, and the polyvalent isocyanate-based A zirconium-based compound ("Orgatics ZC-150" manufactured by Matsumoto Fine Chemical Co., Ltd.) obtained by blending a compound (B-1) and a carbodiimide-based compound (C-1), and further diluted with acetylacetone as a urethanization catalyst to a solid content concentration of 1%. 0.02 part (solid content) was added, stirred and mixed to obtain a polyester resin composition (adhesive composition).
The resulting adhesive composition was applied to a polyethylene terephthalate (PET) film (38 μm thick) 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 pressure-sensitive adhesive layer to protect its surface, and the layer was cured in an atmosphere at a temperature of 40° C. for 10 days to obtain a pressure-sensitive adhesive sheet.

The obtained pressure-sensitive adhesive sheets of Examples and Comparative Examples were evaluated as follows. Evaluation results are shown in Table 3 below.

<Initial adhesive strength (peel strength) (vs. SUS-BA)>
A SUS-BA plate was prepared as an adherend. After cutting the adhesive sheet obtained above to 25 mm × 200 mm in an environment of 23 ° C. and 50% RH, the release film is peeled off, the adhesive layer side is brought into contact with the SUS-BA plate, and a 2 kg roller is reciprocated. It was applied under pressure. Then, after standing 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 (manufactured by Shimadzu Corporation, Autograph AGS-H 500N). , the peeling state was visually observed.

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

<Initial adhesive strength (peel strength) (vs. PP)>
A PP plate was prepared as an adherend. After cutting the adhesive sheet obtained above to 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. Pressed on. Then, after standing 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 (manufactured by Shimadzu Corporation, Autograph AGS-H 500N). , the peeling state was visually observed.

<Holding power (cohesive force)>
According to JIS Z-0237, the pressure-sensitive adhesive sheet obtained above was attached with SUS304 as an adherend with an attachment area of 25 mm × 25 mm, and then left at rest for 20 minutes at 80 ° C. A load of 1 kg was applied, The shift after 24 hours was measured.

From the results in Table 3 above, the adhesive sheets of Examples 1-1 to 5-1 prepared using the polyester resin compositions (adhesive compositions) of Examples 1 to 5 were attached to metal adherends. It has excellent adhesiveness at the initial stage and after aging, and has the desired adhesiveness even to difficult-to-adhere adherends such as polyolefin resins, and has an excellent balance between adhesive strength and holding power. .
Further, the polyester-based resin composition (adhesive composition The pressure-sensitive adhesive sheets of Comparative Examples 1-1 and 2-1, which were prepared using the material), exhibited particularly low adhesive strength over time. Furthermore, although the structural unit derived from the polyvalent carboxylic acid (a2) having a furan skeleton is contained, the content of the structural unit derived from the polyvalent carboxylic acid (a2) having a furan skeleton, the compound (a1) derived In the pressure-sensitive adhesive sheet of Comparative Example 3-1 prepared using the polyester-based resin composition (pressure-sensitive adhesive composition) of Comparative Example 3, which has too few structural units, either initially or after time to the adherend of the metal On the other hand, the adhesive physical properties were inferior, and all the effects of the present invention could not be satisfied.

The polyester-based resin composition of the present invention, the pressure-sensitive adhesive composition containing it, and the pressure-sensitive adhesive have excellent adhesion properties to various adherends such as metals, even when a polyester-based resin with a high degree of biomass is used. It has excellent effects, 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 mobile electronic devices, electronic members, and the like.

Claims (14)

A polyester resin composition containing a polyester resin (A),
The polyester-based resin (A) is 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. containing a structural unit derived from (a1) and further containing a structural unit derived from polyvalent carboxylic acids (a2) having a furan skeleton,
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 acid (a2) in the polyester resin (A) is A polyester-based resin composition characterized in that it is 0.6 or more. 2. The polyester resin composition according to claim 1, wherein the compound (a1) is a plant-derived raw material. 3. The polyester resin composition according to claim 1, wherein the compound (a1) is a dimer acid and/or a dimer diol. 4. The polyester resin composition according to any one of claims 1 to 3, wherein the polycarboxylic acids (a2) are 2,5-furandicarboxylic acids. 5. The polyester resin composition according to any one of claims 1 to 4, wherein the polyester resin (A) has a number average molecular weight of 3000 or more. The polyester resin composition according to any one of claims 1 to 5, wherein the polyester resin (A) has a weight average molecular weight of 10,000 or more. The polyester resin composition according to any one of claims 1 to 6, wherein the polyester resin (A) has a glass transition temperature of -10°C or lower. The polyester resin composition according to any one of claims 1 to 7, wherein the polyester resin (A) has a biomass degree of 50% or more. The polyester resin composition according to any one of claims 1 to 8, further comprising a polyvalent isocyanate compound (B). The polyester resin composition according to any one of claims 1 to 9, further comprising a hydrolysis inhibitor (C). A pressure-sensitive adhesive composition containing the polyester-based resin composition according to any one of claims 1 to 10. A pressure-sensitive adhesive, characterized in that the pressure-sensitive adhesive composition according to claim 11 is crosslinked. A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive according to claim 12. A double-sided pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive according to claim 12.