JP7439561B2 - Polyester adhesive composition, polyester adhesive and adhesive sheet - Google Patents

Description

The present invention relates to a polyester pressure-sensitive adhesive composition, a polyester pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet, and more specifically, a polyester that has excellent chemical resistance and also has excellent adhesiveness to various adherends such as metals and polyolefin members. The present invention relates to a pressure-sensitive adhesive composition, a polyester pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet.

Traditionally, polyester resins have excellent heat resistance, chemical resistance, durability, and mechanical strength, so they have been used in a wide range of applications such as films, PET bottles, fibers, toners, electrical parts, and adhesives and adhesives. It is used.

In addition, in recent years, display devices such as liquid crystal displays (LCDs) and input devices used in combination with the above display devices, such as touch panels, have become widely used. Adhesive sheets are used for bonding optical members such as films and substrates.

As such an adhesive sheet, for example, a film with an adhesive using a polyester adhesive composition having a hydrogenated polybutadiene skeleton is used, and an adhesive that achieves both tackiness and cohesiveness when attached to a metal plate is used. A sheet has been proposed (for example, see Patent Document 1).
In addition, for the purpose of improving adhesive strength and heat resistance, adhesives containing a copolymerized polyester segment with a high glass transition temperature, a block polyester resin containing an aliphatic segment, and a curing agent have been proposed (for example, patented (See Reference 2).

Japanese Patent Application Publication No. 3-167284 JP 2019-23277 Publication

However, although Patent Document 1 provides adhesion to metal plates, it does not take into account adhesion to polyolefin substrates, which generally have poor adhesion, and also has poor chemical resistance. It wasn't satisfying.
Furthermore, in recent years, applications in which polyolefin base materials are used as adherends, such as automobile interior/exterior materials and building materials, have been increasing, and the demand for adhesiveness to polyolefin base materials has become extremely high.
Further, although the above-mentioned Patent Document 2 has good heat resistance, the polyester resin has a low glass transition temperature, so it is not satisfactory in terms of chemical resistance.

In view of this background, the present invention provides a polyester adhesive composition, a polyester adhesive, and an adhesive that has excellent chemical resistance and also has excellent adhesion to various adherends such as metals and polyolefin members. The purpose is to provide sheets.

However, as a result of extensive research in view of the above circumstances, the present inventor has found that a polyester block structural unit derived from a polyester oligomer with a high glass transition temperature and a polymer block structure derived from a polymer with a low glass transition temperature are incorporated into the polyester resin. The present invention was completed by discovering that by using a polyester resin containing repeating units, it is possible to cause phase separation, resulting in a polyester pressure-sensitive adhesive composition with excellent chemical resistance and adhesive properties. did.

That is, the present invention provides a polyester block (X) derived from a polyester oligomer (x) containing a structural unit derived from a polyhydric carboxylic acid (a1) and a structural unit derived from a polyol (a2), and Contains repeatedly the structural unit of the following formula (1) consisting of a polymer block (Y),
X-Y...(1)
The glass transition temperature (Tgβ) of the polymer (y) is -80 to -15°C,
The first aspect is a polyester adhesive composition containing a polyester resin (A) in which the glass transition temperature (Tgα) of the polyester oligomer (x) is higher than the glass transition temperature (Tgβ) of the polymer (y). It is something to do.

The second aspect of the present invention is a polyester adhesive obtained by crosslinking the polyester adhesive composition, and the third aspect of the present invention is a pressure-sensitive adhesive sheet having an adhesive layer containing such a polyester adhesive. shall be.

Generally, in order to improve the chemical resistance of a polyester pressure-sensitive adhesive composition, it is considered to increase the glass transition temperature of the polyester resin. In that case, the resin becomes hard and difficult to use as an adhesive.
In the present invention, an unexpected combination of repeatedly containing a polyester block with a high glass transition temperature and a polymer block with a low glass transition temperature, and more preferably a surprising combination of selecting and containing a polymer block with poor compatibility with the polyester block, is employed. However, in the present invention, by purposely causing phase separation within the molecule, it is possible to avoid contradictory physical properties. They discovered that it is possible to achieve both chemical resistance and adhesion.

In addition, in the above-mentioned Patent Document 2, the resin does not have a phase-separated structure and has a uniform polymer structure, which makes it difficult to achieve both chemical resistance and adhesiveness, which are the objectives of the present invention. It is presumed that this cannot be achieved.

The polyester pressure-sensitive adhesive composition of the present invention repeatedly contains a polyester block structural unit derived from a polyester oligomer having a high glass transition temperature and a polymer block structural unit derived from a polymer having a low glass transition temperature in a polyester resin. Therefore, it has excellent chemical resistance and also has excellent adhesion to various adherends such as metals and polyolefin members.

FIG. 2 shows a chart when the polyester resin (A-1) used in Example 1 was measured with a differential scanning calorimeter. A chart diagram showing the measurement of the polyester resin (A-2) used in Example 2 with a differential scanning calorimeter is shown. A chart diagram is shown when the polyester resin (A-3) used in Example 3 was measured with a differential scanning calorimeter.

Hereinafter, the structure of the present invention will be explained in detail, but these are examples of desirable 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 esters.

<<Polyester resin (A)>>
The polyester resin (A) used in the present invention has a structural unit consisting of a polyester block (X) derived from a polyester oligomer (x) and a polymer block (Y) derived from a polymer (y) as shown in the following formula (1). and the polymer (y) has a low glass transition temperature (Tgβ) within a specific range, and the glass transition temperature (Tgα) of the polyester oligomer (x) is lower than that of the polymer (y). It is characterized by being higher than the glass transition temperature (Tgβ).
X-Y...(1)
Hereinafter, the polyester oligomer (x) constituting the polyester block (X) and the polymer (y) constituting the polymer block (Y) will be described in detail.

<Polyester oligomer (x)>
The polyester oligomer (x) is obtained by esterifying polycarboxylic acids (a1) and polyol (a2). ) and a structural unit derived from polyol (a2).

[Polyhydric carboxylic acids (a1)]
Examples of the polyvalent carboxylic acids (a1) used as a constituent raw material of the polyester oligomer (x) include divalent carboxylic acids and trivalent or higher polyvalent carboxylic acids, which stabilize the polyester resin (A). Dihydric carboxylic acids are preferably used because they are easily obtained.

Examples of the divalent carboxylic acids include malonic acids, dimethylmalonic acids, succinic acids, glutaric acids, adipic acids, trimethyladipic acids, pimelic acids, 2,2-dimethylglutaric acids, azelaic acids, sebacic acids, fumaric acids, Aliphatic dicarboxylic acids such as maleic acids, itaconic acids, thiodipropionic acids, diglycolic acids, 1,9-nonanedicarboxylic acids, dimer acids derived from oleic acid, erucic acid, etc.;
Phthalic acids, terephthalic acids, isophthalic acids, benzylmalonic acids, diphenic acids, 4,4'-oxydibenzoic acids, 1,8-naphthalenedicarboxylic acids, 2,3-naphthalenedicarboxylic acids, 2,7-naphthalenedicarboxylic acids, etc. Aromatic dicarboxylic acids such as naphthalene dicarboxylic acids (a1-1);
Alicyclic acids such as 1,3-cyclopentanedicarboxylic acids, 1,2-cyclohexanedicarboxylic acids, 1,3-cyclopentanedicarboxylic acids, 1,4-cyclohexanedicarboxylic acids, 2,5-norbornanedicarboxylic acids, adamantanedicarboxylic acids, etc. Dicarboxylic acids;
etc.

Examples of the trivalent or higher carboxylic acids include trimellitic acids, pyromellitic acids, adamantanetricarboxylic acids, trimesic acids, and the like.

Further, as the polycarboxylic acids (a1), compounds containing a hydrogenated polybutadiene structure may be used, such as 1,2-polybutadiene dicarboxylic acids, 1,4-polybutadiene dicarboxylic acids, 1,4-isoprene dicarboxylic acids, etc. Examples include polybutadiene-based polycarboxylic acids, and saturated hydrocarbon-based polycarboxylic acids in which the double bonds of these polybutadiene-based carboxylic acids are saturated with hydrogen, halogen, or the like. Further, polycarboxylic acids obtained by copolymerizing polybutadiene-based polycarboxylic acids with olefin compounds such as styrene, ethylene, vinyl acetate, and acrylic esters, and hydrogenated polycarboxylic acids thereof can also be used. Among these, highly saturated hydrocarbon-based polybutadiene polycarboxylic acids are particularly preferred, with a number average molecular weight of 300 to 30,000, more preferably 500 to 10,000, and even more preferably 800 to 5,000. , the average functional number of the carboxy group is 1.5 to 3.

Regarding the hydrogenated polybutadiene structure-containing compound, the higher the proportion of 1,2 bonding sites among the 1,2 bonding sites and 1,4 bonding sites in the hydrogenated polybutadiene structure, the better the adhesiveness to the polyolefin substrate. This is preferable in this respect. Further, the proportion of 1,2 bond sites in the hydrogenated polybutadiene structure is preferably 25 to 100%, particularly preferably 50 to 100%, particularly preferably 75 to 100%.

These polyhydric carboxylic acids (a1) can be used alone or in combination of two or more.
Among the above polycarboxylic acids (a1), aromatic dicarboxylic acids (a1-1) are preferred because of their excellent chemical resistance.

Furthermore, among the aromatic dicarboxylic acids (a1-1), it is preferable to include asymmetric aromatic dicarboxylic acids (a1-1-1) from the viewpoint of lowering the crystallinity of the polyester resin (A). Examples of the asymmetric aromatic dicarboxylic acids (a1-1-1) include phthalic acids, isophthalic acids, 1,8-naphthalenedicarboxylic acids, 2,3-naphthalenedicarboxylic acids, 2,7-naphthalenedicarboxylic acids, etc. Among these, isophthalic acids are particularly preferred from the viewpoint of reactivity.

The content of such asymmetric aromatic dicarboxylic acids (a1-1-1) is preferably 5 to 100 mol%, particularly preferably 20 to 98 mol%, based on the entire polyhydric carboxylic acids (a1). %, more preferably 40 to 95 mol%, particularly preferably 50 to 93 mol%, and even more preferably 60 to 90 mol%. If the content is too low, the resin tends to crystallize and sufficient adhesion performance cannot be obtained; if the content is too high, compatibility and initial adhesion (tack) tend to decrease.

Furthermore, it is also preferable to include aliphatic dicarboxylic acids as the polyhydric carboxylic acids (a1) from the viewpoint of adhesive properties, and sebacic acids and adipic acids are particularly preferable.

The content of such aliphatic dicarboxylic acids is preferably 80 mol% or less, more preferably 2 to 60 mol%, particularly preferably 5 to 50 mol%, based on the entire polycarboxylic acid (a1). , more preferably 7 to 45 mol%, particularly preferably 10 to 40 mol%. If this content is too small, initial adhesion (tack) tends to decrease, and if it is too large, chemical resistance tends to decrease.

In addition, in order to increase the number of branch points in the polyester resin (A), polycarboxylic acids having a valence of 3 or more can also be used, and among them, trimellitic acids are used because they are relatively less likely to cause gelation. is preferred.

The content of the trivalent or higher polyvalent carboxylic acids is preferably 10 mol % or less, particularly preferably 10 mol% or less, based on the entire polyvalent carboxylic acids (a1), since it can increase the cohesive force of the adhesive. The content is 0.1 to 5 mol%, and if the content is too large, gelation tends to occur during the production of the polyester resin (A).

[Polyol (a2)]
As the polyol (a2) used as a constituent raw material of the polyester oligomer (x), there are dihydric alcohols and trihydric or higher hydric polyols. Polyol (a2) can be used alone or in combination of two or more.

Examples of the dihydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, -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, aliphatic diols such as dimer diols derived from oleic acid, erucic acid, etc.;
1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, spiroglycol, tricyclodecanedimethanol, adamantanediol, 2,2,4,4-tetramethyl-1,3 -Alicyclic diols such as cyclobutanediol;
4,4'-thiodiphenol, 4,4'-methylene diphenol, 4,4'-dihydroxybiphenyl, o-, m- and p-dihydroxybenzene, 2,5-naphthalenediol, p-xylene diol, and Examples thereof include aromatic diols such as ethylene oxide adducts and propylene oxide adducts.
Further examples include fatty acid esters derived from castor oil and glycerol monostearate.
Further, examples of the trivalent or higher polyols include pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol, adamantanetriol, and the like.

Further, among the above polyols (a2), it is preferable to contain a branched structure-containing polyol (a2-1) from the viewpoint of increasing branching points and disrupting crystallinity. Examples of the branched structure-containing polyol (a2-1) include neopentyl glycol, 2-methyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, and 2,2-diethyl- 1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2- Examples include methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3,5-trimethyl-1,3-pentanediol, 2-methyl-1,6-hexanediol, etc. It will be done. Among them, neopentyl glycol is particularly preferred.

The content of the branched structure-containing polyol (a2-1) is 5 to 95 mol% based on the entire polyol (a2) [including the polymer (y) when the polymer (y) described below is a polyol]. The amount is preferably from 10 to 90 mol%, more preferably from 15 to 80 mol%. If this content is too small, the polyester resin (A) tends to crystallize and it is difficult to obtain sufficient adhesive performance, and if it is too large, the reaction time tends to be longer in the production of the polyester resin (A). .

On the other hand, among the polyols (a2), it is preferable to contain a linear polyol (a2-2) from the viewpoint of reactivity, and linear polyols having 2 to 40 carbon atoms are more preferable. Examples of such linear polyols (a2-2) include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and dipropylene glycol. , 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol and other aliphatic glycols. Among these, ethylene glycol, 1,4-butanediol, and 1,6-hexanediol are particularly preferred.

The content of the linear polyol (a2-2) is 5 to 95 mol% based on the entire polyol (a2) [including the polymer (y) when the polymer (y) described below is a polyol]. It is preferably 10 to 90 mol%, particularly preferably 15 to 80 mol%. If this content is too small, stable resin formation tends to be difficult to obtain.

Further, trivalent or higher valent polyols can also be used for the purpose of increasing branch points in the polyester resin (A), and examples of the trivalent or higher polyols include pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, Examples include trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol, adamantanetriol, and the like.

The content of such trivalent or higher polyol should be 20 mol% or less based on the entire polyol (a2) [including the polymer (y) when the polymer (y) described below is a polyol]. The content is preferably from 0.1 to 10 mol%, particularly preferably from 0.5 to 5 mol%; if this content is too large, it tends to be difficult to produce the polyester resin (A). be.

The polyester oligomer (x) used in the present invention can be obtained by arbitrarily selecting the above-mentioned polycarboxylic acids (a1) and polyol (a2) and subjecting them to an esterification reaction by a known method in the presence of a catalyst. .

The blending ratio of polyhydric carboxylic acid (a1) and polyol (a2) is preferably 1 to 3 equivalents of polyol (a2) per 1 equivalent of polycarboxylic acid (a1), particularly preferably 1.1. ~2.0 equivalents. If the blending ratio of polyol (a2) is too small, the acid value will tend to be high and it will be difficult to increase the molecular weight, and if it is too large, the yield will tend to decrease.

In such an esterification reaction, a catalyst is used, and specifically, for example, a titanium-based catalyst such as tetraisopropyl titanate or tetrabutyl titanate, an antimony-based catalyst such as antimony trioxide, a germanium-based catalyst such as germanium dioxide, etc. Examples include catalysts such as phosphoric acid, zinc acetate, manganese acetate, and dibutyltin oxide. These catalysts may be used alone or in combination of two or more. Among them, antimony trioxide, tetrabutyl titanate, germanium dioxide, and zinc acetate are preferred, and zinc acetate is particularly preferred, from the viewpoint of high catalytic activity and hue balance.

The amount of the catalyst blended 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 esterification reaction components. If the amount is too small, the esterification reaction tends to be difficult to proceed sufficiently, and if it is too large, there is no advantage such as shortening the reaction time, 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, and even more preferably 220 to 260°C. If the reaction temperature is too low, the reaction tends to be difficult to proceed sufficiently, whereas if it is too high, side reactions such as decomposition tend to occur. Further, the pressure during the reaction is usually normal pressure.

In this way, polyester oligomer (x) is obtained.

The glass transition temperature (Tgα) of the polyester oligomer (x) is preferably -15 to 80°C, more preferably -10 to 50°C, particularly preferably -8 to 40°C, and even more preferably -5 to 30°C. . If the glass transition temperature (Tgα) of the polyester oligomer (x) is too low, chemical resistance tends to decrease, and if the glass transition temperature (Tgα) is too high, adhesiveness tends to decrease.

In the present invention, the glass transition temperature is a value obtained by measuring using a differential scanning calorimeter, and the measurement conditions are a measurement temperature range of -90 to 100°C and a temperature increase rate of 10°C/min.

<Polymer (y)>
The polymer (y) has a low glass transition temperature within a specific range.
The structure of the polymer (y) is not particularly limited as long as it can be copolymerized with the polyester oligomer (x), but it is preferably a polymer polyol having two or more hydroxyl groups, and the main chain Particularly preferred is a polymer polyol having hydroxyl groups at both ends.

A specific example of the polymer (y) is preferably at least one selected from a compound containing a conjugated diene structure, a compound containing a hydrogenated conjugated diene structure, and a compound containing a polyoxyalkylene structure. These may be used alone or in combination of two or more.
The polyester oligomer (x) contains a relatively large number of structural units derived from aromatic structure-containing compounds, and the polymer (y) having the above structure has poor compatibility with such a polyester oligomer (x). By copolymerizing, phase separation occurs within the molecules of the polyester resin (A), resulting in excellent adhesiveness and chemical resistance.

Examples of the conjugated diene structure-containing compound include polybutadiene polyols such as 1,2-polybutadiene polyol, 1,4-polybutadiene polyol, and 1,4-polyisoprene polyol.
Furthermore, polyols obtained by copolymerizing polybutadiene-based polyols with olefin compounds such as styrene, ethylene, vinyl acetate, and acrylic esters can also be used.

Examples of the hydrogenated conjugated diene structure-containing compound include saturating the double bonds of polybutadiene polyols such as 1,2-polybutadiene polyol, 1,4-polybutadiene polyol, and 1,4-polyisoprene polyol with hydrogen or halogen. Examples include saturated hydrocarbon polyols. Furthermore, polyols obtained by hydrogenating polyols obtained by copolymerizing polybutadiene-based polyols with olefin compounds such as styrene, ethylene, vinyl acetate, and acrylic esters can also be used.

Regarding the above-mentioned hydrogenated conjugated diene structure-containing compound, in the 1,2 bonding sites and 1,4 bonding sites in the hydrogenated conjugated diene structure, the higher the proportion of the 1,2 bonding sites, the better the adhesion to the polyolefin substrate. It is preferable because of its excellent properties. Furthermore, the proportion of 1,2 bond sites in the hydrogenated conjugated diene structure is preferably 25 to 100%, particularly preferably 50 to 100%, particularly preferably 75 to 100%. .

Examples of the polyoxyalkylene structure-containing compound include polyoxyalkylene diols such as polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, and copolymers thereof, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. Examples include polyoxyalkylene polyols such as polyoxyalkylene triols obtained by addition polymerization of glycerin, trimethylolpropane, etc., and polyoxytetramethyl glycol obtained by ring-opening polymerization of tetrahydrofuran.

Among these, from the viewpoint of adhesive strength, compounds containing a conjugated diene structure and compounds containing a hydrogenated conjugated diene structure are preferable, compounds containing a hydrogenated conjugated diene structure are more preferable, and highly saturated hydrocarbon-based compounds are particularly preferable. A polybutadiene polyol, particularly preferably one having a number average molecular weight of 300 to 30,000, more preferably 500 to 10,000, even more preferably 800 to 5,000, and an average functional number of hydroxyl groups of 1.5 to 3. It is a highly saturated hydrocarbon polybutadiene polyol.

The glass transition temperature (Tgβ) of the polymer (y) needs to be -80 to -15°C. The temperature is preferably -75 to -20°C, more preferably -70 to -25°C, even more preferably -60 to -30°C. If the glass transition temperature (Tgβ) is too high, adhesion (tack) will decrease. In addition, the said glass transition temperature (Tg(beta)) is the value obtained by measuring by the same method as the said polyester type oligomer (x).

Further, in the present invention, from the viewpoint of adhesive strength and chemical resistance, it is necessary that the glass transition temperature (Tgα) of the polyester oligomer (x) is higher than the glass transition temperature (Tgβ) of the polymer (y). It is.
The difference (Tgα−Tgβ) between the glass transition temperature (Tgα) of the polyester oligomer (x) and the glass transition temperature (Tgβ) of the polymer (y) is usually 5°C or more, preferably 10°C or more, more preferably is 15°C or higher. If the difference between the two is too small, chemical resistance and initial adhesion (tack) tend to decrease. Note that the upper limit is usually 100°C.

The number average molecular weight of the polymer (y) is preferably 300 to 30,000, more preferably 500 to 10,000, particularly preferably 800 to 5,000. If the number average molecular weight is too small, initial adhesion tends to decrease, and if it is too large, chemical resistance tends to decrease.

In the present invention, the number average molecular weight is a number average molecular weight calculated in terms of standard polystyrene molecular weight, and a high performance liquid chromatograph (manufactured by Tosoh Corporation, "HLC-8320GPC") is equipped with a column: TSKgel SuperMultipore HZ-M (exclusion limit molecular weight: The ^weight A similar method can be used to determine the average molecular weight.

The polyester resin (A) used in the present invention is obtained by copolymerizing the polyester oligomer (x) and the polymer (y).

The reaction conditions for the above copolymerization include using a catalyst, setting the reaction temperature to preferably 220 to 280°C, particularly preferably 230 to 270°C, gradually reducing the pressure in the reaction system, and finally reducing the pressure to 5 hPa or less. It is preferable to allow the reaction to occur for up to 10 hours. If the reaction temperature is too low, the reaction tends to be difficult to proceed sufficiently, whereas if it is too high, side reactions such as decomposition tend to occur.

As the catalyst, the same catalysts as those exemplified for the esterification reaction of the polyhydric carboxylic acid (a1) and polyol (a2) can be used. Among these, tetrabutyl titanate and phosphoric acid are preferred, and it is particularly preferred to use tetrabutyl titanate and phosphoric acid in combination.

Further, the amount of the catalyst blended 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. If the amount is too small, the polymerization reaction tends to be difficult to proceed sufficiently, and if the amount is too large, there is no advantage such as shortening the reaction time, and side reactions tend to occur easily.

In this way, the polyester resin (A) used in the present invention is obtained.

Such a polyester resin (A) repeatedly contains a structural unit consisting of a polyester block (X) derived from a polyester oligomer (x) and a polymer block (Y) derived from a polymer (y) as shown in the following formula (1). It is something to do.
X-Y...(1)

The content ratio of the polymer block (Y) constituting the polyester resin is preferably 0.1 to 80% by weight based on the polyester resin (A) from the viewpoint of balance between adhesion and chemical resistance. , more preferably 2 to 70% by weight, particularly preferably 5 to 60% by weight, particularly preferably 15 to 40% by weight. If the content of the polymer block (Y) is too low, adhesion tends to decrease, and if the content is too high, chemical resistance tends to decrease.

Further, the polyester block (X) constituting the polyester resin preferably contains 20 mol% or more of structural units derived from an aromatic structure-containing compound, more preferably 40 mol% or more, particularly preferably 50 mol%. The content is more preferably 60 mol% or more. Note that the upper limit is usually 100 mol%. If there are too few structural units derived from aromatic structure-containing compounds, chemical resistance tends to decrease.

Further, the content of the structural unit derived from the aromatic ring structure-containing compound in the polyester resin (A) is usually 1 to 70% by weight, preferably 10 to 65% by weight, particularly preferably 20 to 60% by weight, More preferably, it is 25 to 55% by weight. When the content of the structural unit derived from the aromatic ring structure-containing compound is within the above range, chemical resistance will be excellent.

Furthermore, it is believed that the structural unit derived from the aromatic ring structure-containing compound in the polyester resin (A) is contained as at least one of the structural unit derived from the polyhydric carboxylic acid (a1) and the structural unit derived from the polyol (a2). It is preferable from the viewpoint of drug properties, and more preferably contained as a structural unit derived from polyhydric carboxylic acids (a1).

Furthermore, when the structural unit derived from the aromatic dicarboxylic acids (a1-1) is included as a structural unit derived from the polyhydric carboxylic acids (a1), the structural unit derived from the aromatic dicarboxylic acids (a1-1) is It is preferable to contain 20 to 100 mol% in the structural unit derived from polyhydric carboxylic acids (a1) from the viewpoint of chemical resistance, more preferably 40 to 98 mol%, particularly preferably 50 to 95 mol%, especially Preferably it is 55 to 93 mol%, more preferably 60 to 90 mol%.

In addition, when the structural unit derived from the asymmetric aromatic dicarboxylic acid (a1-1-1) is included as a structural unit derived from the polycarboxylic acid (a1), the asymmetric aromatic dicarboxylic acid (a1-1- The structural unit derived from 1) preferably contains 5 to 100 mol% in the structural unit derived from the polycarboxylic acid (a1), particularly preferably 20 to 98 mol%, even more preferably 40 to 95 mol%, Particularly preferably 50 to 93 mol%, more preferably 60 to 90 mol%.

On the other hand, when the structural unit derived from the branched structure-containing polyol (a2-1) is included as a structural unit derived from the polyol (a2), the structural unit derived from the branched structure-containing polyol (a2-1) is ) in the structural unit derived from [polymer (y) is also included when polymer (y) is a polyol] contains 5 to 95 mol % from the viewpoint of disrupting crystallinity, particularly 10 to 90 mol %. , more preferably 15 to 80 mol%.

Furthermore, when the structural unit derived from the linear polyol (a2-2) is included as a structural unit derived from the polyol (a2), the structural unit derived from the linear polyol (a2-2) is derived from the polyol (a2). In terms of stable resin formation, it is preferable to contain 5 to 95 mol% in the structural unit [including polymer (y) when polymer (y) is a polyol], and more preferably 10 to 90 mol%. , particularly preferably 15 to 80 mol%.

Here, the structural unit ratio (composition ratio) derived from each component of the polyester resin (A) can be determined by, for example, NMR.

The polyester resin (A) has a peak glass transition temperature (Tg) when measured using a differential scanning calorimeter under the measurement conditions of -90 to 100°C and a temperature increase rate of 10°C/min. It is preferable to have at least two, preferably two, from the viewpoint of adhesive strength and chemical resistance.
The above two or more glass transition temperature peaks originate from the polyester oligomer (x) and the polymer (y). In other words, when the compatibility between the polyester oligomer and the polymer is high, there is normally one glass transition temperature peak, but the polyester resin (A) is intentionally compatible with the polyester oligomer (x). By copolymerizing the polymer (y) with a low carbon content with the polyester oligomer (x), phase separation occurs within the molecule, resulting in two or more peaks, preferably two peaks. The polyester resin (A) is composed of a polyester block (X) derived from a polyester oligomer (x) having excellent chemical resistance and a polymer block (Y) derived from a polymer (y) having excellent adhesive properties. Since the structural unit (1) is repeatedly contained, it is possible to achieve both chemical resistance and adhesiveness.

When the polyester resin (A) has two glass transition temperature peaks, the higher glass transition temperature is preferably -15°C or higher, more preferably -15 to 80°C, and even more preferably - The temperature is 10 to 50°C, particularly preferably -8 to 40°C, particularly preferably -5 to 30°C. On the other hand, the lower glass transition temperature is preferably -80 to -15°C, more preferably -75 to -20°C, still more preferably -70 to -25°C, particularly preferably -60 to -30°C. It is.

The weight average molecular weight of the polyester resin (A) is preferably 3,000 to 300,000, more preferably 5,000 to 200,000, particularly preferably 10,000 to 150,000. If the weight average molecular weight is too small, sufficient cohesive force cannot be obtained as an adhesive, and chemical resistance and mechanical strength tend to decrease. If it is too large, gel There is a tendency for resins to become difficult to obtain. In addition, the above-mentioned weight average molecular weight is a value measured by the above-mentioned method.

It is preferable that the polyester resin (A) does not crystallize from the viewpoint of storage stability, but even if it crystallizes, it is preferable that the crystallization energy of the polyester resin (A) is as low as possible, usually 35 J/g. Below, it is preferably 20 J/g or less, particularly preferably 10 J/g or less, particularly preferably 5 J/g or less.

The acid value of the polyester resin (A) is preferably 10 mgKOH/g or less, particularly preferably 3 mgKOH/g or less, and more preferably 1 mgKOH/g or less. If the acid value is too high, there is a tendency for corrosion to occur when a layer of metal or the like is laminated on one side of the adhesive layer. For example, when a metal oxide thin film layer is used, corrosion tends to occur and the conductivity of the metal oxide thin film tends to decrease. Note that the lower the acid value is, the more preferable it is, but the lower limit is usually 0.001 mgKOH/g.
Here, the acid value of the polyester resin (A) is determined by neutralization titration based on JIS K 0070.

<Hydrolysis inhibitor (B)>
The polyester adhesive composition of the present invention (hereinafter sometimes abbreviated as "adhesive composition") preferably contains a hydrolysis inhibitor (B) together with the polyester resin (A). This hydrolysis inhibitor (B) is contained in order to ensure long-term durability.

As the above-mentioned hydrolysis inhibitor (B), conventionally known ones can be used, and examples include compounds that react with and bond to the carboxyl terminal group of the above-mentioned polyester resin (A). Examples thereof include compounds containing functional groups such as carbodiimide groups, epoxy groups, and oxazoline groups. Among these, carbodiimide group-containing compounds are preferred because they are highly effective in eliminating the catalytic activity of protons derived from carboxy terminal groups.

As the above-mentioned carbodiimide group-containing compound, a known carbodiimide having one or more carbodiimide groups (-N=C=N-) in the molecule may be used, but it has the advantage of increasing durability under high temperature and high humidity conditions. It is preferably a compound containing two or more carbodiimide groups in the molecule, that is, a polyvalent carbodiimide compound, particularly a compound containing three or more, more preferably five or more, particularly seven or more. is preferred. 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 and compatibility tends to decrease. It is also preferable to use a high molecular weight polycarbodiimide produced by subjecting a diisocyanate to a decarboxylation condensation reaction in the presence of a carbodiimidation catalyst.
Furthermore, it is preferable that the terminal isocyanate group of the high molecular weight polycarbodiimide be capped with a capping agent from the viewpoint of storage stability. Examples of the sealing agent include a compound having an active hydrogen that reacts with an isocyanate group, or a compound having an isocyanate group. Examples 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.

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, Examples include 4'-dicyclohexylmethane diisocyanate and tetramethylxylylene diisocyanate, and these may 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.

Examples of commercially available carbodiimide group-containing compounds include 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 are preferable because they have excellent compatibility with organic solvents.

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

Specific examples of the glycidyl ester compounds include benzoic acid glycidyl ester, t-Bu-benzoic acid glycidyl ester, p-toluic acid glycidyl ester, cyclohexanecarboxylic acid glycidyl ester, pelargonic acid glycidyl ester, stearic acid glycidyl ester, and laurin. Acid glycidyl ester, palmitic acid glycidyl ester, behenic acid glycidyl ester, versatile acid glycidyl ester, oleic acid glycidyl ester, linoleic acid glycidyl ester, linolenic acid glycidyl ester, behenolic acid glycidyl ester, stearic acid glycidyl ester, terephthalic acid diglycidyl ester , isophthalic acid diglycidyl ester, phthalic acid diglycidyl ester, naphthalene dicarboxylic acid diglycidyl ester, methyl terephthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, cyclohexanedicarboxylic acid diglycidyl ester, adipine These include acid diglycidyl ester, succinic acid diglycidyl ester, sebacate diglycidyl ester, dodecanedioic acid diglycidyl ester, octadecanedicarboxylic acid diglycidyl ester, trimellitic acid triglycidyl ester, pyromellitic acid tetraglycidyl ester, etc. These 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 the reaction of bisphenol such as methane and epichlorohydrin, and the like can be mentioned, and these can be used alone or in combination of two or more kinds.

As the oxazoline group-containing compound, bisoxazoline compounds and the like are preferred. 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'-diphenylenebis(2-oxazoline), etc. Among these, 2,2'-bis(2-oxazoline) is the most preferable from the viewpoint of reactivity with the polyester resin. . Moreover, these can be used alone or in combination of two or more.

As these hydrolysis inhibitors (B), it is preferable that the volatility is low, and therefore it is preferable to use one with a high number average molecular weight, usually 300 to 10,000, preferably 1,000 to 5,000. It is.
Further, as the hydrolysis inhibitor (B), 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 (B) is preferably 500 or more, more preferably 1,000 or more, even more preferably 2,000 or more, and 3,000 or more. is particularly preferred. Note that the upper limit of the weight average molecular weight is usually 50,000.
If the molecular weight of the hydrolysis inhibitor (B) is too small, hydrolysis resistance tends to decrease. Note that if the molecular weight is too large, the compatibility with the polyester resin (A) tends to decrease.

Among the hydrolysis inhibitors (B), it is preferable to use a compound containing a carbodiimide group, in which case the carbodiimide equivalent is preferably 50 to 10,000, particularly 100 to 1,000, and even 150. It is preferably 500 to 500. Note that the carbodiimide equivalent indicates the chemical formula weight per carbodiimide group.

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

Further, the content of the hydrolysis inhibitor (B) is preferably optimized depending on the acid value of the polyester resin (A). ) The molar ratio [(b)/(a)] of the total number of moles (b) of the functional groups of the hydrolysis inhibitor (B) in the adhesive composition to the total number of moles (a) of the acidic functional groups of , 0.5≦(b)/(a), particularly preferably 1≦(b)/(a)≦1,000, even more preferably 1.5≦(b)/(a)≦ It is 100.
If the molar ratio of (b) to (a) is too low, the moisture and heat resistance performance tends to decrease. Note that if the molar ratio of (b) to (a) is too high, the compatibility with the polyester resin (A) tends to decrease, and the adhesive strength, cohesive force, and durability tend to decrease.

<Crosslinking agent (C)>
It is preferable that the adhesive composition of the present invention further contains a crosslinking agent (C), and by containing the crosslinking agent (C), the polyester resin (A) is crosslinked with the crosslinking agent (C) and coagulated. It has excellent strength and can improve its performance as an adhesive.

Examples of the crosslinking agent (C) include compounds having a functional group that reacts with at least one of the hydroxyl group and the carboxy group contained in the polyester resin (A), such as polyisocyanate compounds and polyepoxy compounds. Among these, it is particularly preferable to use polyisocyanate compounds because they can achieve a good balance of initial adhesion, mechanical strength, and heat resistance.

Examples of such polyisocyanate compounds include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, 1 , 5-naphthalene diisocyanate, triphenylmethane triisocyanate, etc., as well as adducts of the above polyisocyanates and polyol compounds such as trimethylolpropane, burettes and isocyanates of these polyisocyanate compounds. Nurate form, etc. can be mentioned. In addition, the above polyisocyanate-based compounds can also be used even if the isocyanate moiety is blocked with phenol, lactam, or the like. These crosslinking agents (C) may be used alone or in combination of two or more.

The content of the crosslinking agent (C) can be appropriately selected depending on the molecular weight of the polyester resin (A) and the purpose of use, but it is usually 1 equivalent of at least one of the hydroxyl group and the carboxyl group contained in the polyester resin (A). It is preferable that the crosslinking agent (C) is contained in a proportion such that the reactive groups contained in the crosslinking agent (C) are 0.2 to 10 equivalents, particularly preferably 0.5 to 5 equivalents, and more preferably 0.5 to 5 equivalents, and more preferably Preferably it is 0.5 to 3 equivalents.
If the equivalent number of reactive groups contained in the crosslinking agent (C) is too small, the cohesive force tends to decrease, and if it is too large, the flexibility tends to decrease.

In addition, in the reaction between the polyester resin (A) and the crosslinking agent (C), an organic solvent that does not have a functional group that reacts with these components (A) and (C), such as an ester such as ethyl acetate or butyl acetate, may be used. Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatics such as toluene and xylene can be used. These can be used alone or in combination of two or more.

<Urethanization catalyst (D)>
It is more preferable that the pressure-sensitive adhesive composition of the present invention contains a urethanization catalyst (D) from the viewpoint of reaction rate.

Examples of the urethanization catalyst (D) include organometallic compounds, tertiary amine compounds, and the like. These can be used alone or in combination of two or more.

Examples of the organometallic compounds include zirconium compounds, iron compounds, tin compounds, titanium compounds, lead compounds, cobalt compounds, and zinc compounds.
Examples of the zirconium compounds include zirconium naphthenate and zirconium acetylacetonate.
Examples of iron-based compounds include iron acetylacetonate and iron 2-ethylhexanoate.
Examples of the tin-based compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dilaurate, and the like.
Examples of the titanium-based compound include dibutyltitanium dichloride, tetrabutyltitanate, butoxytitanium trichloride, and the like.
Examples of lead-based compounds include lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate.
Examples of cobalt-based compounds 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 (D), organometallic compounds are preferred, and zirconium compounds are particularly preferred, in terms of reaction rate and pot life of the adhesive layer. Further, it is preferable to use acetylacetone as a catalytic action inhibitor in combination with the urethanization catalyst (D). Containing acetylacetone is preferable because it suppresses catalytic action at low temperatures and lengthens the pot life.

In addition to the above-mentioned polyester resin (A), hydrolysis inhibitor (B), crosslinking agent (C), and urethanization catalyst (D), the adhesive composition of the present invention also has the effects of the present invention. Additives such as antioxidants such as hindered phenols, softeners, ultraviolet absorbers, stabilizers, antistatic agents, tackifiers, and other inorganic or organic fillers, metal powders, to the extent that they do not impair the Powdered or particulate additives such as pigments can be blended. These can be used alone or in combination of two or more.

Moreover, the polyester adhesive (hereinafter sometimes abbreviated as "adhesive") according to the present invention is obtained by crosslinking the above-mentioned adhesive composition.

The pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer containing the above-mentioned pressure-sensitive adhesive on one or both sides of a supporting base material.
In the present invention, the term "sheet" includes "film" and "tape."

<Adhesive sheet>
The adhesive sheet can be produced, for example, as follows.
Such a pressure-sensitive adhesive sheet can be produced according to a known general method for producing pressure-sensitive adhesive sheets. For example, the above-mentioned pressure-sensitive adhesive composition is coated on a base material, dried, and the pressure-sensitive adhesive composition on the opposite side is coated. By laminating a release sheet on the material layer surface and curing if necessary, the pressure-sensitive adhesive sheet of the present invention having a pressure-sensitive adhesive layer containing a pressure-sensitive adhesive on the base material can be obtained.

Alternatively, the pressure-sensitive adhesive sheet of the present invention can be obtained by coating the above-mentioned pressure-sensitive adhesive composition on a release sheet, drying it, laminating a base material on the opposite side of the pressure-sensitive adhesive composition layer, and curing if necessary. It will be done.

Moreover, a base material-less double-sided pressure-sensitive adhesive sheet can be manufactured by forming a pressure-sensitive adhesive layer on a release sheet and bonding the release sheet to the opposite side of the pressure-sensitive adhesive layer.

When using the resulting pressure-sensitive adhesive sheet or base material-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 is bonded to the adherend.

Examples of the base material include polyester resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate/isophthalate copolymers; polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; polyvinyl fluoride; Polyfluorinated ethylene 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; A sheet made of at least one synthetic resin selected from the group consisting of cycloolefin polymers, etc.; Metal foil of aluminum, copper, iron; Paper such as high-quality paper and glassine paper; Glass Examples include woven fabrics and nonwoven fabrics made of fibers, natural fibers, synthetic fibers, and the like. These base materials can be used as a single layer body or a multilayer body in which two or more types are laminated.

Among these, base materials made of polyethylene terephthalate and polyimide are particularly preferred, and polyethylene terephthalate is particularly preferred since it has excellent adhesiveness with adhesives.

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

The thickness of the base material is preferably, for example, 1 to 1,000 μm, particularly preferably 2 to 500 μm, and even more preferably 3 to 300 μm.

As the above-mentioned release sheet, for example, a sheet made of the various synthetic resins exemplified as the above-mentioned base material, paper, cloth, nonwoven fabric, etc., which has been subjected to a release treatment can be used. As the release sheet, it is preferable to use a silicone release sheet.

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

The conditions for the above curing treatment are usually room temperature (23°C) to 70°C and time usually 1 to 30 days. Specifically, for example, 23°C for 1 to 20 days, preferably 23°C. It may be carried out under conditions such as 3 to 14 days, 1 to 10 days at 40°C.

Further, regarding the drying conditions, the drying temperature is preferably 60 to 140°C, particularly preferably 80 to 120°C, and the drying time is preferably 0.5 to 30 minutes, particularly preferably 1 to 5 minutes.

The thickness of the adhesive layer of the above-mentioned adhesive sheet and base material-less double-sided adhesive sheet is preferably 2 to 500 μm, particularly preferably 5 to 200 μm, and even more preferably 10 to 100 μm. If the thickness of the adhesive layer is too thin, the adhesive strength tends to decrease, and if it is too thick, it becomes difficult to apply it uniformly, and problems such as bubbles in the coating film tend to occur. be. In addition, when considering shock absorption property, it is preferable to set it as 50 micrometers or more.

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 "ID-C112B" manufactured by Mitutoyo. .

The gel fraction of the adhesive layer of the above-mentioned adhesive sheet is preferably 10% by weight or more from the viewpoint of durability and adhesive strength, particularly preferably 30 to 90% by weight, and even more preferably 50 to 85% by weight. be. If the gel fraction is too low, the cohesive force decreases, which tends to decrease chemical resistance. Note that if the gel fraction is too high, the adhesive force tends to decrease due to an increase in cohesive force.

The above gel fraction serves as a measure of the degree of crosslinking, and is calculated, for example, by the following method. That is, an adhesive sheet (without a release sheet) consisting of a polymer sheet (such as PET film) as a base material and an adhesive layer formed thereon is wrapped in a 200-mesh SUS wire mesh and placed in toluene. The wire gauze is immersed at 23°C for 24 hours, and the weight percentage of the undissolved adhesive component remaining in the wire gauze after immersion is defined as the gel fraction relative to the weight of the adhesive component before immersion. However, the weight of the base material should be deducted.

Furthermore, such a pressure-sensitive adhesive sheet may be protected by providing a release sheet on the outside of the pressure-sensitive adhesive layer, if necessary. In addition, for pressure-sensitive adhesive sheets in which the pressure-sensitive adhesive layer is formed on one side of the base material, by applying a peeling treatment to the surface of the base material opposite to the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer can be layered using the peel-treated surface. It is also possible to protect

The pressure-sensitive adhesive of the present invention can be used for bonding various members, but it is particularly preferable to use it for bonding members that come into contact with chemicals such as organic solvents.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In addition, "part" and "%" in the examples mean a weight basis.
Furthermore, the glass transition temperature in the following examples was measured according to the method described above.

Prior to Examples, polyester resin (A) was prepared.

<Production of polyester resin (A)>
The mol% of the structural unit ratio derived from the finished component of polyvalent carboxylic acids (a1) described in the following production examples indicates the molar ratio when the total amount of polyvalent carboxylic acids (a1) is 100 mol%. .
In addition, the mol% of the structural unit ratio derived from finished components of polyol (a2) and polymer (y) described in the following production examples refers to the total amount of polyol (a2) and polymer (y) as 100 mol%. The molar ratio is shown below.

[Production of polyester resin (A-1)]
327.7 parts (70 mol%) of isophthalic acid (IPA) and adipine as polyhydric carboxylic acids (a1) were placed in a reaction vessel equipped with a heating device, a thermometer, a stirrer, a rectification column, a nitrogen introduction tube, and a vacuum device. Acid (AdA) 123.6 parts (30 mol%), ethylene glycol (EG) 96.2 parts (55 mol%) as polyol (a2), 1,6-hexanediol (1.6HG) 183.1 parts ( 55 mol%), 117.4 parts (40 mol%) of neopentyl glycol (NPG), and 0.05 part of zinc acetate as a catalyst, gradually raised the temperature to 250°C and esterified over 4 hours. The reaction was carried out to prepare a polyester oligomer (x) (glass transition temperature (Tgα) -4°C) [corresponding to the polyester block (X) portion of the polyester resin to be obtained later].
Thereafter, hydrogenated polybutadiene polyol (manufactured by Nippon Soda Co., Ltd., "GI-1000 '', glass transition temperature (Tgβ) -42.3°C, number average molecular weight 1,500) was added, 152.1 parts (3.6 mol%) was added, the internal temperature was raised to 260°C, and 0.05% of tetrabutyl titanate was added as a catalyst. 1 part and 0.1 part of phosphoric acid were charged, the pressure was reduced to 1.33 hPa, and a polymerization reaction was carried out over 3 hours to produce a polyester resin (A-1) [weight average molecular weight 42,000].
The glass transition temperature of the obtained polyester resin (A-1) was -4°C and -32°C, and there were two glass transition temperature peaks (see FIG. 1).
The peak at the glass transition temperature of -4°C is derived from the polyester oligomer (x), and the peak at -32°C is derived from the polymer (y). This is a measurement of the polyester resin after polymerization, and is due to the glass transition temperature of the polyester oligomer (x) and polymer (y) before polymerization.In addition, in the polyester oligomer (x), the above Although it does not completely match the glass transition temperature obtained from the measured peak, it is an approximate value.) The polyester resin (A-1) obtained from this has phase separation within the molecule, with a polyester block (X) derived from the polyester oligomer (x) and a polymer block (Y) derived from the polymer (y). It can be seen that it contains
The structural unit ratio derived from the finished components of the polyester resin (A-1) (hereinafter sometimes abbreviated as "finished component ratio") is isophthalic acid/adipic acid = 70 mol as the polyhydric carboxylic acid (a1). %/30 mol%, as polyol [(a2) + polymer (y)] ethylene glycol/1,6-hexanediol/neopentyl glycol/hydrogenated polybutadiene polyol = 33.2 mol%/38 mol%/25.2 The ratio was mol%/3.6 mol%. Further, the structural unit derived from the aromatic structure-containing compound contained in the polyester block (X) is 35.6 mol%, and the content ratio of the polymer block (Y) is 20% by mole with respect to the polyester resin (A-1). It was .0%.

[Production of polyester resin (A-2)]
311.8 parts (70 mol%) of isophthalic acid (IPA) and adipine as polyhydric carboxylic acids (a1) were placed in a reaction vessel equipped with a heating device, thermometer, stirrer, rectification column, nitrogen introduction tube, and vacuum device. Acid (AdA) 117.6 parts (30 mol%), ethylene glycol (EG) 91.5 parts (55 mol%) as polyol (a2), 1,6-hexanediol (1.6HG) 174.3 parts ( 55 mol%), 111.67 parts (40 mol%) of neopentyl glycol (NPG), and 0.05 part of zinc acetate as a catalyst, gradually raised the temperature to 250°C and esterified over 4 hours. The reaction was carried out to prepare a polyester oligomer (x) (glass transition temperature (Tgα) -4°C) [corresponding to the polyester block (X) of the polyester resin to be obtained later].
Thereafter, hydrogenated polybutadiene polyol (manufactured by Nippon Soda Co., Ltd., "GI-1000", glass transition Temperature (Tgβ) -42.3°C, number average molecular weight 1,500) was added (193.1 parts (4.8 mol%)), the internal temperature was raised to 260°C, and 0.05 part of tetrabutyl titanate and phosphoric acid were added as catalysts. 0.1 part was charged, the pressure was reduced to 1.33 hPa, and a polymerization reaction was carried out over 3 hours to produce polyester resin (A-2) [weight average molecular weight 47,000].
The glass transition temperature of the obtained polyester resin (A-2) was -4°C and -33°C, and there were two glass transition temperature peaks (see Figure 2).
The finished component ratio of the polyester resin (A-2) is: isophthalic acid/adipic acid = 70 mol%/30 mol% as polycarboxylic acids (a1), ethylene as polyol [(a2) + polymer (y)] Glycol/1,6-hexanediol/neopentyl glycol/hydrogenated polybutadiene polyol=32.7 mol%/37.6 mol%/24.9 mol%/4.8 mol%. Further, the structural unit derived from the aromatic structure-containing compound contained in the polyester block (X) is 35.9 mol %, and the content ratio of the polymer block (Y) is 25.9 mol % with respect to the polyester resin (A-2). It was 1%.

[Manufacture of polyester resin (A-3)]
295.2 parts (70 mol%) of isophthalic acid (IPA) and adipine as polyhydric carboxylic acids (a1) were placed in a reaction vessel equipped with a heating device, thermometer, stirrer, rectification column, nitrogen introduction tube, and vacuum device. Acid (AdA) 111.3 parts (30 mol%), ethylene glycol (EG) 86.7 parts (55 mol%) as polyol (a2), 1,6-hexanediol (1.6HG) 165 parts (55 mol%) %), 105.8 parts (40 mol%) of neopentyl glycol (NPG), and 0.05 part of zinc acetate as a catalyst, the temperature was gradually raised to an internal temperature of 250°C, and the esterification reaction was carried out over 4 hours. A polyester oligomer (x) (glass transition temperature (Tgα) -5°C) [corresponding to the polyester block (X) of the polyester resin to be obtained later] was prepared.
Thereafter, hydrogenated polybutadiene polyol (manufactured by Nippon Soda Co., Ltd., "GI-1000", glass transition Temperature (Tgβ) -42.3°C, number average molecular weight 1,500), 236.1 parts (6.2 mol%) were charged, the internal temperature was raised to 260°C, and 0.05 part of tetrabutyl titanate and phosphoric acid were added as catalysts. 0.1 part was charged, the pressure was reduced to 1.33 hPa, and a polymerization reaction was carried out over 3 hours to produce polyester resin (A-3) [weight average molecular weight 51,000].
The glass transition temperature of the obtained polyester resin (A-3) was -5°C and -33°C, and there were two glass transition temperature peaks (see FIG. 3).
The finished component ratio of the polyester resin (A-3) is: isophthalic acid/adipic acid = 70 mol%/30 mol% as polycarboxylic acids (a1), ethylene as polyol [(a2) + polymer (y)] Glycol/1,6-hexanediol/neopentyl glycol/hydrogenated polybutadiene polyol=32.1 mol%/37.2 mol%/24.5 mol%/6.2 mol%. The structural unit derived from the aromatic structure-containing compound contained in the polyester block (X) is 36.1 mol%, and the content ratio of the polymer block (Y) is 30.3% with respect to the polyester resin (A-3). Met.

[Production of polyester resin (A'-1)]
96.1 parts (20 mol%) of isophthalic acid (IPA) and sebacine as polyhydric carboxylic acids (a1) were placed in a reaction vessel equipped with a heating device, thermometer, stirrer, rectification column, nitrogen inlet tube, and vacuum device. 467.8 parts (80 mol%) of acid (SebA), 29.7 parts (8.7 mol%) of 1,6-hexanediol (1.6HG) as polyol (a2), 271 parts of neopentyl glycol (NPG). (90 mol%), 130.3 parts (50 mol%) of 1,4-butanediol (1.4BG), and 5 parts (1.3 mol%) of trimethylolpropane (TMP), 0.3 parts of zinc acetate as a catalyst. 05 parts were charged, the temperature was gradually raised to an internal temperature of 250°C, and the esterification reaction was carried out over 4 hours.
Thereafter, the internal temperature was raised to 260°C, 0.05 part of tetrabutyl titanate and 0.1 part of phosphoric acid were added as catalysts, the pressure was reduced to 1.33 hPa, a polymerization reaction was carried out over 3 hours, and polyester resin (A' -1) was produced.
The glass transition temperature of the obtained polyester resin (A'-1) was -50°C, and the finished component ratio was as follows: isophthalic acid/sebacic acid = 20 mol%/80 mol% as polycarboxylic acids (a1), polyol ( As a2), 1,6-hexanediol/neopentyl glycol/1,4-butanediol/trimethylolpropane=6.2 mol%/58.5 mol%/34 mol%/1.3 mol%.

[Production of polyester resin (A'-2)]
386.5 parts (70 mol%) of isophthalic acid (IPA) and adipine as polyhydric carboxylic acids (a1) were placed in a reaction vessel equipped with a heating device, thermometer, stirrer, rectification column, nitrogen introduction tube, and vacuum device. 145.7 parts (30 mol%) of acid (AdA), 113.4 parts (55 mol%) of ethylene glycol (EG) as polyol (a2), 216 parts (55 mol%) of 1,6-hexanediol (1.6HG). %), 138.4 parts (40 mol%) of neopentyl glycol (NPG), and 0.05 part of zinc acetate as a catalyst, the temperature was gradually raised to an internal temperature of 250°C, and the esterification reaction was carried out over 4 hours. went.
Thereafter, the internal temperature was raised to 260°C, 0.05 part of tetrabutyl titanate was charged as a catalyst, the pressure was reduced to 1.33 hPa, and a polymerization reaction was carried out over 3 hours to produce polyester resin (A'-2).
The glass transition temperature of the obtained polyester resin (A'-2) was -5°C, and the finished component ratio was as follows: isophthalic acid/adipic acid = 70 mol%/30 mol% as polycarboxylic acids (a1), polyol ( As a2), ethylene glycol/1,6-hexanediol/neopentyl glycol=34.6 mol%/39.2 mol%/26.2 mol%.

The results of the resin composition (finished component ratio) and glass transition temperature (Tg) of the obtained polyester resin (A) or (A') are also shown in Table 1 below.

<Manufacture of polyester adhesive composition>
Polyester pressure-sensitive adhesive compositions of the following Examples and Comparative Examples were manufactured using each of the polyester resins obtained above.

(Example 1)
The polyester resin (A-1) obtained above was diluted with toluene to a solid concentration of 50%, and 200 parts of this polyester resin (A-1) solution (100 parts as solid content) was added to inhibit hydrolysis. 1 part (solid content) of a trimethylolpropane/tolylene diisocyanate adduct (manufactured by Tosoh Corporation, "Coronate L55E") as a crosslinking agent (manufactured by Nisshinbo Chemical Co., Ltd.) (solid content) , by blending 0.02 part (solid content) of a zirconium compound (manufactured by Matsumoto Fine Chemical Co., Ltd., "Orgatics ZC-150") diluted with acetylacetone to a solid concentration of 1% as a urethanization catalyst, and stirring and mixing. A polyester adhesive composition was obtained.

(Example 2)
A polyester pressure-sensitive adhesive composition was obtained in the same manner as in Example 1, except that the polyester resin (A-1) in Example 1 was changed to polyester resin (A-2).

(Example 3)
A polyester adhesive composition was obtained in the same manner as in Example 1, except that the polyester resin (A-1) was changed to polyester resin (A-3) and the crosslinking agent was changed to 5 parts. Ta.

(Comparative example 1)
A polyester adhesive composition was prepared in the same manner as in Example 1, except that the polyester resin (A-1) was changed to polyester resin (A'-1) and the crosslinking agent was changed to 1.25 parts. I got something.

(Comparative example 2)
A polyester adhesive composition was prepared in the same manner as in Example 1, except that the polyester resin (A-1) was changed to polyester resin (A'-2) and the crosslinking agent was changed to 3 parts. Obtained.

The obtained polyester pressure-sensitive adhesive composition was evaluated as follows. The results are shown in Table 2 below.

<Production of adhesive sheet with one-sided release film>
The polyester adhesive compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were applied onto a 38 μm thick PET film (“Lumirror T60” manufactured by Toray Industries, Inc.) using an applicator, and heated at 100°C. The mixture was dried for 3 minutes to obtain a PET film-attached pressure-sensitive adhesive sheet with a pressure-sensitive adhesive composition layer having a thickness of 25 μm.
Next, the surface of the adhesive composition layer of the obtained pressure-sensitive adhesive sheet with a PET film was covered with a PET release film having a thickness of 38 μm, and an aging treatment was performed at 40° C. for 4 days to obtain a pressure-sensitive adhesive sheet with a single-sided release film.

<Adhesive sheet evaluation>
[Adhesive force]
The adhesive sheet with a single-sided release film obtained above was cut into 25 mm x 200 mm in an environment of 23°C and 50% RH, the release film was peeled off, and the adhesive layer side was cut into 25 mm x 200 mm pieces. - BA board) and polypropylene (PP) board by moving a 2 kg roller back and forth to apply pressure, and after standing for 30 minutes in the same atmosphere, apply Autograph (manufactured by Shimadzu Corporation, "Autograph AG-X"). The degree of 180 degree peeling (N/25 mm) was measured at a peeling speed of 300 mm/min.

[chemical resistance]
The adhesive sheet with a single-sided release film obtained above was wrapped in a 200 mesh SUS wire mesh, and immersed in toluene at 23°C for 30 minutes. The weight percentage of the undissolved adhesive component remaining therein was determined, and this was taken as the gel fraction (G1) after immersion for 30 minutes. However, the weight of the PET film should be deducted.
Similarly, an adhesive sheet with a release film on one side was wrapped in a 200-mesh SUS wire mesh, and immersed in toluene at 23°C for 24 hours. The weight percentage of the undissolved adhesive component remaining therein was determined, and this was taken as the gel fraction (G2) after 24-hour immersion. However, the weight of the PET film should be deducted.

Using the above gel fractions (G1) and (G2), the retention rate (%) was calculated according to the formula below, and the chemical resistance was evaluated according to the evaluation criteria below.
Maintenance rate (%) = 100 - ([100-30 minute immersion gel fraction (G1)] / [100-24 hour immersion gel fraction (G2)]) x 100
(Evaluation criteria)
◎...Retention rate is 60% or more ○...Retention rate is 40% or more and less than 60% △...Retention rate is 30% or more and less than 40% ×...Retention rate is less than 30%

From the results in Table 2 above, the polyester adhesive compositions of Examples 1 to 3 have excellent adhesiveness not only to SUS-BA boards but also to polyolefin substrates such as PP boards, Furthermore, it had excellent chemical resistance.
On the other hand, although Comparative Example 1 has a polyester resin with a low glass transition temperature and excellent adhesive properties, it does not contain a polymer block with a low glass transition temperature and has a low glass transition temperature, so it has poor chemical resistance. Met. Comparative Example 2 has good chemical resistance because the glass transition temperature of the polyester resin is high, but since it does not contain a polymer block with a low glass transition temperature, the adhesion is low and it does not peel off against the SUS-BA base material. Zipping occurred and the adhesion to the polyolefin substrate was poor.
Therefore, it can be seen that the examples are excellent polyester pressure-sensitive adhesive compositions that have both adhesion to metal and polyolefin substrates and chemical resistance.

The polyester adhesive composition of the present invention has excellent adhesion to adherends such as metals and polyolefin substrates, and also has excellent chemical resistance, so adhesives and adhesive sheets using it are suitable for displays and other applications. It can be suitably used for bonding optical members such as optical films and base materials that constitute the optical members.

Claims (14)

From a polyester block (X) derived from a polyester oligomer (x) containing a structural unit derived from a polyvalent carboxylic acid (a1) and a structural unit derived from a polyol (a2), and a polymer block (Y) derived from a polymer (y) It repeatedly contains the structural unit of the following formula (1),
X-Y...(1)
The glass transition temperature (Tgα) of the polyester oligomer (x) is -15 to 30°C,
The glass transition temperature (Tgβ) of the polymer (y) is -80 to -15°C, the number average molecular weight of the polymer (y) is 300 to 30,000,
A polyester pressure-sensitive adhesive composition comprising a polyester resin (A) in which the glass transition temperature (Tgα) of the polyester oligomer (x) is higher than the glass transition temperature (Tgβ) of the polymer (y). From a polyester block (X) derived from a polyester oligomer (x) containing a structural unit derived from a polyvalent carboxylic acid (a1) and a structural unit derived from a polyol (a2), and a polymer block (Y) derived from a polymer (y) It repeatedly contains the structural unit of the following formula (1),
X-Y...(1)
The glass transition temperature (Tgβ) of the polymer (y) is -80 to -15°C, and the polymer (y) is at least one compound selected from a conjugated diene structure-containing compound and a hydrogenated conjugated diene structure-containing compound. is a seed,
A polyester pressure-sensitive adhesive composition comprising a polyester resin (A) in which the glass transition temperature (Tgα) of the polyester oligomer (x) is higher than the glass transition temperature (Tgβ) of the polymer (y). The polyester pressure-sensitive adhesive composition according to claim 2, wherein the number average amount of the polymer (y) is 300 to 30,000. The polyester according to any one of claims 1 to 3, wherein the polyester resin (A) is a polyester resin in which the polyester oligomer (x) and the polymer (y) are copolymerized. adhesive composition. The polyester resin (A) has a peak glass transition temperature (Tg) when measured using a differential scanning calorimeter under the measurement conditions of a temperature range of -90 to 100°C and a temperature rise rate of 10°C/min. The polyester pressure-sensitive adhesive composition according to any one of claims 1 to 4, characterized in that it has at least two or more. The polyester adhesive composition according to any one of claims 2 to 5, wherein the polyester oligomer (x) has a glass transition temperature (Tgα) of -15 to 80°C. The polyester pressure-sensitive adhesive composition according to any one of claims 1 to 6, wherein the polyester block (X) contains 20 mol% or more of structural units derived from an aromatic structure-containing compound. The polyester adhesive composition according to any one of claims 1 to 7, wherein the polyester resin (A) has a weight average molecular weight of 3,000 to 300,000. The polyester adhesive according to any one of claims 1 to 8, wherein the content ratio of the polymer block (Y) is 0.1 to 80% by weight based on the polyester resin (A). agent composition. The polyester pressure-sensitive adhesive composition according to any one of claims 1 to 9, further comprising a hydrolysis inhibitor (B). The polyester adhesive composition according to any one of claims 1 to 10, further comprising a crosslinking agent (C). The polyester pressure-sensitive adhesive composition according to any one of claims 1 to 11, further comprising a urethanization catalyst (D). A polyester pressure-sensitive adhesive characterized in that the polyester pressure-sensitive adhesive composition according to any one of claims 1 to 12 is crosslinked. An adhesive sheet comprising an adhesive layer containing the polyester adhesive according to claim 13.

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