Adhesive layer and adhesive sheet

Abstract

To provide an adhesive layer which has good adhesive force to various adherends even in the case of a thin film and little change in adhesive force with time.SOLUTION: There is provided an adhesive layer obtained by crosslinking an adhesive composition comprising a polyester-based resin (i) having structural moieties derived from polycarboxylic acids (a) and a structural moiety derived from a polyol component (b), wherein the adhesive layer has a thickness of 18 μm or less and contains 60 mol% or more of structural moieties derived from aliphatic dicarboxylic acids (a1) having 8 or less carbon atoms of the structural moieties derived from the polycarboxylic acids (a).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an adhesive layer, particularly suitable for joining housings and parts of portable electronic devices. The present invention relates to a thin adhesive layer and an adhesive sheet used in the above. [Background technology]

[0002] Adhesive tapes and adhesive sheets bond substrates and components together without the need for heat or other energy. It is easy to work with and can be used as a highly reliable joining method for office equipment and home appliances. It is used for fixing parts in various industrial fields such as electrical appliances. As the functionality of electronic devices has increased, efforts have been made to make them smaller and thinner, and they are now used in computers and digital video cameras. In addition, electronic organizers, mobile phones, PHS, smartphones, game devices, e-books, etc. There is a particularly strong demand for smaller and thinner portable electronic terminals. In this case, the main components have been made thinner, and the adhesive tape used to fasten them has also been improved. However, there is a demand for thinner devices.

[0003] For fixing components of mobile electronic terminals such as the above-mentioned mobile phones, thin film displays, etc., or for fixing components of optical discs. Transparent film with excellent adhesive strength and high temperature retention, suitable for laminating plates and fixing polarizing plates. As an example of a thin double-sided adhesive tape, Patent Document 1 discloses a tape in which butyl acrylate is attached to both sides of a core material. Acrylate ester copolymer containing 90% or more by mass of acrylic units and having a weight average molecular weight of 700,000 or more The adhesive layer is formed from an adhesive composition containing a specific amount of a tackifier. A double-sided film with a thickness of 30 μm or less and a thickness of the adhesive layer on each side of 2 to 10 μm. Adhesive tape has been suggested.

[0004] For example, Patent Document 2 discloses a method for producing a glycosaminoglycan comprising an aromatic dicarboxylic acid and a glycosaminoglycan having a hydrocarbon in the side chain. The essential ingredients are alcohol and polyhydric alcohols (3 or more) and / or polycarboxylic acids (3 or more). and a polyester obtained by polycondensation of a specific amount of polyhydric alcohol and / or polycarboxylic acid. By using a cellulose-based resin, an adhesive with excellent adhesive properties and heat resistance can be obtained, and it can be applied with finger pressure. It exerts sufficient adhesive strength at pressures of 10 ... Pressure-sensitive adhesives containing polyester resins that can be used in a wide range of applications have been proposed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-169327 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-99879 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the techniques disclosed in Patent Documents 1 and 2 mentioned above do not provide a thin film that adheres to various adherends. The adhesive strength is insufficient, and further improvement is required. The acrylic adhesives used in this technique generally have low elastic modulus and low cohesive strength, so they form a thin adhesive layer. However, when peeled off, adhesive residue was easily left behind, and there was room for further improvement.

[0007] In addition, this adhesive has a high elastic modulus and cohesive strength (it is difficult for the adhesive to crack and leave residue when peeled off). Polyester-based adhesives have also been considered as adhesives, but the polyester adhesives disclosed in the above Patent Document 2 The use of steric adhesives in thin films has not been disclosed. When the adhesive strength is increased, it is not fully developed, and further improvement is required. there were.

[0008] Traditionally, acrylic adhesives have been widely used, but in recent years, polyester adhesives have become more popular. Polyester adhesives are more widely used than acrylic adhesives. It has high heat resistance and is therefore excellent for use in electronic components, etc., and is also polyethylene terephthalate It is also compatible with ester films, such as PET, so it is not suitable for acrylic adhesives. In many cases, polyester adhesives can be used in places where it is difficult to use adhesives. There is a growing demand for measures to reduce environmental impact, but when it comes to disposal, polyester adhesives are decomposed into By combining them, it is possible to return them to oligomers or monomers. It can be said to be more environmentally friendly than using kryl-based adhesives.

[0009] Therefore, in this invention, under such circumstances, even if it is a thin film, it is possible to apply it to various adherends. A pressure-sensitive adhesive layer and a pressure-sensitive adhesive sheet that have good adhesive strength and little change in adhesive strength over time. In some cases, when the thin adhesive layer is used for adhesion, even if the initial adhesive strength is low, To provide a thin adhesive sheet whose adhesive strength increases over time. [Means for solving the problem]

[0010] The present inventors have found that the adhesive strength of polyester adhesives is less dependent on the thickness of the adhesive layer. Focusing on this, a polyester resin was used as the resin constituting the adhesive composition, and It was discovered that by using a polyethylene-based adhesive, it is possible to make the adhesive layer thinner while maintaining adhesive strength. did. The reason why the adhesive strength is less dependent on the thickness of the adhesive layer is not clear, but Since adhesives have a high elastic modulus and are difficult to deform, the energy required to deform the adhesive bulk is The adhesion between the interfaces contributes less to the adhesive strength. This is thought to be due to the fact that In addition, when using polyester adhesives to achieve strong adhesive strength with a thin film, the adhesion of the interface is important as mentioned above. In order to improve adhesion, it is important to increase polarity. Increasing the steric bond concentration is thought to be effective. On the other hand, it is necessary to have a thin film that is compatible with the material. Therefore, the softness of the adhesive must also be taken into consideration, and the adhesive's glass transition temperature (Tg) must be low. It is preferable to design the compound by taking these factors into consideration and to select an aliphatic dicarboxylic acid having a relatively short carbon difference. It has been found that the above problems can be more effectively solved by introducing a certain amount.

[0011] That is, the present invention has the following aspects [1] to

[14] . [1] A structural portion derived from polycarboxylic acids (a) and a structural portion derived from a polyol component (b) a pressure-sensitive adhesive layer in which a pressure-sensitive adhesive composition containing a polyester resin (i) having a crosslinking moiety is crosslinked; There was, The thickness of the pressure-sensitive adhesive layer is 18 μm or less, Among the structural moieties derived from the polycarboxylic acids (a), aliphatic dicarboxylic acids having 8 or less carbon atoms A pressure-sensitive adhesive layer containing 60 mol % or more of structural moieties derived from class (a1). [2] The structural moiety derived from the polyol component (b) is ethylene glycol, 2-methyl a small amount selected from the group consisting of 1,3-propanediol and neopentyl glycol The pressure-sensitive adhesive layer according to [1], which contains a structural moiety derived from at least one species. [3] The structural moiety derived from the aliphatic dicarboxylic acid (a1) having 8 or less carbon atoms is adipine. The adhesive layer according to [1] or [2], wherein the structural moiety is derived from an acid. [4] The ester bond concentration of the polyester resin (i) is 9 to 12.5 mmol / The pressure-sensitive adhesive layer according to any one of [1] to [3], wherein the value is g. [5] The glass transition temperature of the polyester resin (i) is -50 to -10°C. The pressure-sensitive adhesive layer according to any one of [1] to [4]. [6] The structural portion derived from the polycarboxylic acid (a) and the structural portion derived from the polyol component (b) A polyester resin (i) having a structural moiety is crosslinked by a crosslinking agent (ii) [1] to [ 5]. The pressure-sensitive adhesive layer according to any one of [1] to [5]. [7] The adhesive according to [6], wherein the crosslinking agent (ii) is an isocyanate-based crosslinking agent (ii-1). agent layer. [8] A pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer according to any one of [1] to [7] and a substrate. The base material is laminated on one side of the pressure-sensitive adhesive layer, and the other side is a release-treated sheet. Adhesive sheet. [9] The pressure-sensitive adhesive sheet according to [8], wherein the substrate is a polyester resin sheet.

[10] A pressure-sensitive adhesive layer according to any one of [1] to [7] and a release-treated sheet. A pressure-sensitive adhesive sheet in which the release-treated sheets are laminated on both sides of the pressure-sensitive adhesive layer. Route.

[11] The pressure-sensitive adhesive sheet according to [8] or [9], wherein the adherend is a polyimide.

[12] The adhesive sheet according to [8] or [9], which is used to fix electronic components.

[13] The adhesive strength (N / 25mm) measured under the following conditions is expressed as X, the thickness of the adhesive layer (μm ) is defined as Y, X / Y≧0.5. to. [Adhesive strength (N / 25mm) measurement conditions] The adhesive sheet was cut into 25mm x 200mm pieces under an environment of 23°C and 50% RH, and then released. The film was peeled off, and the adhesive layer side was placed on a SUS-BA plate as the adherend, and a 2 kg load was applied. Then, after leaving it in the same atmosphere for 30 minutes, A rough (Shimadzu Corporation, Autograph AGS-H 500N) was used at a peeling speed of 300 The 180-degree peel strength (N / 25 mm) measured in mm / min was used as the adhesive strength.

[14] A structural portion derived from polycarboxylic acids (a) and a structural portion derived from a polyol component (b) A pressure-sensitive adhesive composition containing a polyester resin (i') having a structural moiety is crosslinked. A pressure-sensitive adhesive sheet having a layer, The thickness of the pressure-sensitive adhesive layer is 18 μm or less, An adhesive sheet whose adhesive strength over time measured under the following conditions is 5N / 25mm or more. [Measurement conditions for adhesive strength over time (N / 25mm)] The adhesive sheet was cut into 25mm x 200mm pieces under an environment of 23°C and 50% RH, and then the adhesive was The adhesive layer is placed against a SUS-BA plate as the adherend, and a 2 kg roller is moved back and forth to apply pressure. After leaving it to stand for 24 hours under the same atmosphere, the sample was analyzed by an autograph (Shimadzu Corporation, The peel rate was measured at 300 mm / min using a graph AGS-H 500N. The 80 degree peel strength (N / 25 mm) is taken as the adhesive strength over time. [Effects of the Invention]

[0012] The pressure-sensitive adhesive layer of the present invention has excellent adhesive strength to various adherends even when it is a thin film. The pressure-sensitive adhesive layer of the present invention has little change in adhesive strength between the initial stage and the time course. exhibits sufficient adhesive strength from the beginning. Therefore, the pressure-sensitive adhesive layer of the present invention can be used as a single-sided or double-sided pressure-sensitive adhesive sheet for polyimide, a pressure-sensitive adhesive sheet for optical components, or the like. Single-sided or double-sided adhesive sheets used for bonding components of mobile electronic devices, electronic components It is suitable for use as a single-sided or double-sided adhesive sheet for fixing. DETAILED DESCRIPTION OF THE INVENTION

[0013] The configuration of the present invention will be described in detail below, but these are examples of preferred embodiments. It is something. In the present invention, the term "carboxylic acid" refers to acids such as carboxylic acids as well as carbo Salts of carboxylic acids, etc., anhydrides of carboxylic acids, etc., halides of carboxylic acids, etc., esters of carboxylic acids, etc. It also includes derivatives of carboxylic acids such as esters.

[0014] The pressure-sensitive adhesive layer according to one embodiment of the present invention comprises a structural moiety derived from polycarboxylic acids (a) and Adhesive containing polyester resin (i) having a structural portion derived from polyol component (b) a pressure-sensitive adhesive layer in which the adhesive composition is crosslinked, The thickness of the pressure-sensitive adhesive layer is 18 μm or less, Among the structural moieties derived from the polycarboxylic acids (a), aliphatic dicarboxylic acids having 8 or less carbon atoms It is characterized by containing 60 mol % or more of structural moieties derived from class (a1). The pressure-sensitive adhesive sheet according to one embodiment of the present invention further comprises a structural part derived from polycarboxylic acids (a). and a polyester resin (i') having a structural moiety derived from the polyol component (b). A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which a pressure-sensitive adhesive composition having The thickness of the pressure-sensitive adhesive layer is 18 μm or less, It is characterized by an adhesive strength over time of 5N / 25mm or more measured under specific measurement conditions. Each component contained in the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer of the present invention will be described below in order. do.

[0015] <Polyester Resins (i) and (i')> The polyester resin (i) used in the present invention has a structure derived from a polycarboxylic acid (a). a structural portion derived from the polyol component (b), and Among the structural moieties derived from the aliphatic dicarboxylic acids (a1) having 8 or less carbon atoms, The content is 60 mol % or more, preferably 70 mol % or more, and particularly preferably 75 mol % or more. That is why. The upper limit is usually 100 mol %, and preferably 98 mol %. The agent layer contains a specific amount of a structural moiety derived from an aliphatic dicarboxylic acid (a1) having 8 or less carbon atoms. Because it contains polyester resin (i), it has excellent adhesive strength to various adherends even when it is thin. The adhesive strength is excellent and the change in adhesive strength between the initial stage and over time is small. The polyester resin (i') used in the present invention is derived from polycarboxylic acids (a). The polyol component (b) has a structural moiety derived from the polyol component (b) and a structural moiety derived from the polyol component (b).

[0016] [Structural moiety derived from polycarboxylic acids (a)] In the polyester resin (i), the structural part derived from the polycarboxylic acid (a) aliphatic dicarboxylic acids (a1) having 8 or less carbon atoms (including the carbon atom of the carboxyl group) The polycarboxylic acid (a) is characterized in that the structural moiety derived from the polycarboxylic acid (a) is 60 mol % or more of the total polycarboxylic acid (a). do.

[0017] (Structural moiety derived from aliphatic dicarboxylic acids (a1) having 8 or less carbon atoms) Examples of the structural moiety derived from the aliphatic dicarboxylic acids (a1) having 8 or less carbon atoms include: Malonic acids, dimethylmalonic acids, succinic acids, glutaric acids, adipic acids, pimeline Acids, suberic acids, diglycolic acids with carbon numbers of 8 or less, and other straight-chain aliphatic dicarboxylic acids The conventional structural moieties, methylsuccinic acids, 2,2-dimethylglutaric acids, 1,3-dimethylglutaric acids, aliphatic dicarboxylic acids with alkyl groups on the side chain, such as butyl phthalic acid and dimethyl adipic acid structural moieties derived from sulfur-containing dicarboxylic acids such as thiodipropionic acids, Structures derived from unsaturated group-containing aliphatic dicarboxylic acids such as carboxylic acids, maleic acids, and itaconic acids Among these, structural moieties derived from linear aliphatic dicarboxylic acids are preferred. These may be contained alone or in combination of two or more kinds. The structural moiety derived from adipic acid has excellent adhesion and little change in adhesive strength over time. preferable. In addition, the structural moiety derived from the aliphatic dicarboxylic acid (a1) having 8 or less carbon atoms is adipine. The acid-derived structural moiety provides excellent adhesion to various substrates even in thin films, and This is preferable in that there is little change in adhesive strength between the initial stage and over time.

[0018] The content of the structural moiety derived from the aliphatic dicarboxylic acid (a1) having 8 or less carbon atoms is Usually 60 mol % or more, preferably 70 mol % based on the structural portion derived from the carboxylic acids (a). It is particularly preferably 75 mol % or more. The upper limit of the content of the structural moiety derived from the class (a1) is usually 100 mol %, preferably 98 mol %. The content of the structural portion derived from the aliphatic dicarboxylic acid (a1) having 8 or less carbon atoms is If the value is above this, the adhesive strength to various substrates is excellent and there is little change in adhesive strength between the initial stage and over time. There is a tendency to disappear.

[0019] (Structural moieties derived from other polycarboxylic acids) As a structural portion derived from polyvalent carboxylic acids (a) contained in the polyester resin (i), In addition to the structural portion derived from the aliphatic dicarboxylic acids (a1) having 8 or less carbon atoms, Dicarboxylic acids with 9 or more carboxylic acids, aromatic dicarboxylic acids, polycarboxylic acids with 3 or more carboxylic acids, etc. The compound may contain structural moieties derived from other polycarboxylic acids. These may be used alone or in combination of two or more. The above may also be contained in combination.

[0020] Examples of the structural moiety derived from dicarboxylic acids having 9 or more carbon atoms include trimethylazinonitrile, Pyric acids, pimelic acids, azelaic acids, thiodipropionic acids, diglycerides with 9 or more carbon atoms Structural moieties derived from aliphatic dicarboxylic acids such as licoric acids and 1,9-nonanedicarboxylic acids 1,3-Cyclopentanedicarboxylic acids, 1,2-Cyclohexanedicarboxylic acids, 1 ,3-cyclopentanedicarboxylic acids, 1,4-cyclohexanedicarboxylic acids, 2,5 Alicyclic dicarboxylic acids such as norbornanedicarboxylic acids and adamantanedicarboxylic acids Examples of structural parts derived from the nucleotide sequence include:

[0021] Examples of the structural units derived from aromatic dicarboxylic acids include phthalic acids, terephthalic acids, and the like. Acids, isophthalic acids, benzylmalonic acids, diphenic acids, 4,4'-oxydibenzoic acid acids, and further 1,8-naphthalenedicarboxylic acids, 2,3-naphthalenedicarboxylic acids, Aromatic dicarboxylic acids such as naphthalenedicarboxylic acids such as 2,7-naphthalenedicarboxylic acids Examples include structural moieties derived from acids.

[0022] Examples of the structural moiety derived from the trivalent or higher polyvalent carboxylic acids include trimellitic acids Structural moieties derived from pyromellitic acids, adamantanetricarboxylic acids, trimesic acids, etc. Examples include:

[0023] Among the structural moieties derived from the other polyvalent carboxylic acids, polyester resin (i) In order to reduce the crystallinity of the It is preferred that the dicarboxylic acid derivative contains a structural moiety derived from a dicarboxylic acid.

[0024] Examples of the structural moiety derived from the asymmetric aromatic dicarboxylic acids include phthalic acids, iodo- Sophthalic acids, 1,8-naphthalenedicarboxylic acids, 2,3-naphthalenedicarboxylic acids Among them, the structural moiety derived from isophthalic acid is particularly prominent in terms of reactivity. Preferred.

[0025] The structural moiety derived from the aromatic dicarboxylic acids, particularly the structural moiety derived from asymmetric aromatic dicarboxylic acids The content of the structural moiety is usually 1 to 40 with respect to the structural moiety derived from the polycarboxylic acid (a). % by mole, preferably 2 to 30 mol %, particularly preferably 3 to 25 mol %. If the content of structural moieties derived from carboxylic acids is too high, the initial adhesive strength and tackiness tend to decrease. be.

[0026] In addition, the structural unit derived from the polycarboxylic acid (a) contained in the polyester resin (i') The moiety is not particularly limited, but may be a polycarboxylic acid ( It is preferable that the structural unit is derived from a).

[0027] [Structural moiety derived from polyol component (b)] The structural portion derived from the polyol component (b) contained in the polyester resins (i) and (i') The structural moiety is derived from a dihydric alcohol (b1), and the structural moiety is derived from a trihydric or higher polyol (b2). These may be contained alone or in combination of two or more kinds. In particular, in the present invention, the polyester resins (i) and (i') are those obtained by dissolving a dihydric alcohol ( b1) and a structural moiety derived from a trivalent or higher polyol (b2). It is preferable.

[0028] (Structural moiety derived from dihydric alcohol (b1)) Examples of the structural moiety derived from the dihydric alcohol (b1) include ethylene glycol, Diethylene glycol, triethylene glycol, propylene glycol, dipropylene Glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1, 3-diol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol Propanediol (neopentyl glycol), 2-ethyl-2-butyl-1,3-propanediol 2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butane Diol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol Aliphatic dimers such as benzoyl alcohol, dimer diol derived from oleic acid, erucic acid, etc. oar-derived structural sites; 1,2-Cyclohexanedimethanol, 1,3-Cyclohexanedimethanol, 1,4- Cyclohexanedimethanol, spiroglycol, tricyclodecane dimethanol, ada Mantanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, etc. Structural moieties derived from alicyclic diols; 4,4'-thiodiphenol, 4,4'-methylenediphenol, 4,4'-dihydroxy Biphenyl, o-, m-, and p-dihydroxybenzene, 2,5-naphthalenediol p-Xylenediol, and their ethylene oxide adducts and propylene oxide Examples of structural moieties include those derived from aromatic diols such as side adducts. Furthermore, fatty acid esters derived from castor oil and glycerol monostearate, etc. Among these, a structural moiety derived from an aliphatic diol is preferred.

[0029] The structural portion derived from the aliphatic diol is a structural portion derived from an aliphatic diol having a straight chain structure. It can also be distinguished as a structural moiety derived from an aliphatic diol having a hydrocarbon group in the side chain. do.

[0030] In such a case, the content of the structural portion derived from the linear aliphatic diol is 1 to 100 mol %, preferably 10 to 80 mol %, based on the structural moiety derived from the amine component (b). %, more preferably 20 to 75 mol %, and particularly preferably 40 to 70 mol %. If the content is too low, the reactivity of the polyester resins (i) and (i') during production will decrease. If the content ratio is too high, the polyester resin (i), (i ') crystallizes, and the initial adhesive strength of the adhesive tends to decrease.

[0031] The structural moiety derived from the linear aliphatic diol is a linear aliphatic diol having 2 to 18 carbon atoms. A structural moiety derived from an aliphatic diol is preferred, and the polarity can be increased by increasing the concentration of ester bonds. In terms of the fact that it is easy to increase the thin film adhesive strength, an aliphatic diol having 4 or less carbon atoms is particularly preferred. The following structural moieties are preferred. Specifically, ethylene glycol, 1,3-propanediol, A structural moiety derived from 1,4-butanediol, particularly preferably a structural moiety derived from ethylene glycol This is the original structural part.

[0032] In addition, the content of the structural portion derived from the aliphatic diol having a hydrocarbon group in the side chain is 5 to 100 mol %, preferably 20 to 90 mol % based on the structural moiety derived from component (b). The content is more preferably 25 to 80 mol %, and particularly preferably 28 to 60 mol %. If the proportion is too low, the polyester resins (i) and (i') will crystallize, resulting in the initial adhesion of the adhesive. If the content is too high, the adhesive strength of the polyester resin tends to decrease. (i) tends to be less reactive during production.

[0033] Examples of the structural moiety derived from an aliphatic diol having a hydrocarbon group in the side chain include dipropyl Dimethylhexane-1,3-diol, 2-methyl-2-ethylhexane-1,3-diol 2,2-dimethyl-1,3-propanediol (Neopentyl-1,3-propanediol) 2-Methyl-2-ethyl-1,3-propanediol, 2-ethyl -2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol Panediol, 1,3-butanediol, 3-methyl-1,5-pentanediol, 2, Structural moieties derived from 2,4-trimethyl-1,6-hexanediol, dimer diol, etc. Among them, 2,2-dimethyl-1,3-propanediol (neopentylglycerol) chol), and structural moieties derived from 2-methyl-1,3-propanediol are preferred.

[0034] (Structural moiety derived from trivalent or higher polyol (b2)) In the present invention, the crosslinking agent (ii) is used to form a reactive site with the crosslinking agent (ii) described later and to enhance the cohesive force. As a structural portion derived from the polyol component (b), a structural portion derived from a trivalent or higher polyol (b2) It is preferred that the aryl group contains a aryl group.

[0035] The content of the structural moiety derived from the trihydric or higher polyol (b2) is It is preferably 20 mol % or less, and more preferably 0. The content is preferably 1 to 10 mol %, and particularly preferably 0.5 to 5 mol %. If the content of the polyol (b2) is too high, the polyester resins (i) and (i') may be deteriorated. They tend to be difficult to manufacture.

[0036] Examples of the structural moiety derived from the trivalent or higher polyol (b2) include 2-ethyl-2-hydroxybenzoates. Hydroxymethyl-1,3-propanediol (trimethylolpropane), trimethylol Luetane, Glycerin, Pentaerythritol, 1,2,4-Butanetriol, 1,2 ,5-pentanetriol, and 1,2,6-hexanetriol-derived structural moieties. Among these, trimethylolpropane-derived structures are preferred because they are less likely to form gels. It is particularly preferred that the aryl group contains a aryl group moiety.

[0037] In the present invention, the adhesive strength to various adherends and the change in adhesive strength between the initial stage and over time are measured. In view of the fact that the structural moiety derived from the polyol component (b) is small, ethylene glycol, 2- Selected from the group consisting of methyl-1,3-propanediol, and neopentyl glycol It is preferable that the polyol component (b) contains a structural moiety derived from at least one of the polyols The structural moiety is derived from ethylene glycol and / or neopentyl glycol It is particularly preferable that the compound has the structural moiety: The mole ratio of ethylene glycol / neopentyl glycol is 10 / 90 to 10 / 90, especially 20 / 75 to 25 / 80 is preferable, and 40 / 60 to 70 / 30 is even more preferable.

[0038] The above ethylene glycol, 2-methyl-1,3-propanediol, and neopentyl The content of the structural moiety derived from at least one selected from the group consisting of poly(ethylene glycol) and poly(ethylene glycol) is Usually 70 mol % or more, preferably 80 mol % of the structural units derived from the all component (b). More preferably, it is 90 mol % or more, with the upper limit being 100 mol %.

[0039] In the present invention, the structural moieties derived from each component of the polyester resins (i) and (i') The ratio (composition ratio) can be determined by a known method using NMR, for example, 1 H-NMR measurement (proton nuclear magnetic resonance spectroscopy), 13 C-NMR measurement (carbon type nuclear magnetism) This can be determined by methods such as gas resonance spectroscopy.

[0040] The polyester resins (i) and (i') used in the present invention are derived from polycarboxylic acids (a). In addition to the structural portion derived from the polyol component (b), there are carboxylic acid and hydroxyl groups in the molecule. The structural moiety derived from a compound (for example, lactic acid) having both of the above-mentioned features is added to the extent that the effect of the present invention is not impaired. However, since the structural portion derived from lactic acid is easily hydrolyzed, It is preferable not to do so.

[0041] [Production of Polyester Resins (i) and (i')] The polyester resins (i) and (i') of the present invention are obtained by mixing the above-mentioned polycarboxylic acid (a) and The polyol component (b) is used as a raw material and is subjected to a polycondensation reaction in the presence of a catalyst by a known method. That is, the polyester resin (i) and the polyester resin (i) can be produced by ') is obtained by polycondensation reaction of polycarboxylic acid (a) and polyol component (b), Therefore, the structural portion derived from the polycarboxylic acid (a) and the structural portion derived from the polyol component (b) This will result in the following: In the polycondensation reaction, an esterification reaction or an ester exchange reaction was first carried out. If it is not necessary to obtain a high molecular weight, the esterification reaction is carried out. Alternatively, it may be produced solely by transesterification.

[0042] The blending ratio of the polycarboxylic acid (a) and the polyol component (b) is as follows: It is preferable that the amount of the polyol component (b) is 1 to 2 equivalents per equivalent of the carboxylic acid (a), The particularly preferred range is 1.1 to 1.7 equivalents. If the acid value is too high, it tends to be difficult to increase the molecular weight, and if it is too high, the yield tends to decrease. There is.

[0043] [Esterification reaction or transesterification reaction] In the esterification reaction or transesterification reaction, a catalyst is usually used. Examples of suitable titanium catalysts include tetraisopropyl titanate and tetrabutyl titanate. catalysts, antimony-based catalysts such as antimony trioxide, germanium-based catalysts such as germanium dioxide Examples of catalysts include catalysts such as zinc acetate, manganese acetate, and dibutyltin oxide. One or more of these can be used. Among these, those with high catalytic activity are preferred. From the balance between the color of the reaction product and the color of the resulting product, antimony trioxide, tetrabutyl titanate , germanium dioxide, and zinc acetate are preferred.

[0044] The amount of the catalyst to be blended is 1 to 10,000 ppm based on the total copolymerization components (by weight). It is particularly preferable that the concentration is 10 to 5000 ppm, and further preferably 20 to 300 If the blending amount is too small, the polymerization reaction tends to proceed insufficiently. If the amount is too large, there is no advantage such as shortening the reaction time, and side reactions tend to occur.

[0045] The reaction temperature during esterification or transesterification is 200 to 300°C. The temperature is preferably 210 to 280°C, particularly 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, decomposition and the like may occur. The reaction is usually carried out under atmospheric pressure.

[0046] The polycondensation reaction carried out after the esterification reaction or transesterification reaction is The reaction conditions are the same as those used in the above esterification reaction or transesterification reaction. The catalyst is further added in an amount of about the same, and the reaction temperature is preferably 220 to 280°C, particularly preferably The reaction temperature is kept at 230-270°C, and the pressure in the reaction system is gradually reduced until the reaction is completed at 5 hPa or less. If the reaction temperature is too low, the reaction tends to proceed slowly. If the temperature is too high, side reactions such as decomposition tend to occur.

[0047] The ester bond concentration of the polyester resins (i) and (i') obtained above is 9 to 12 0.5 mmol / g, and more preferably 9.2 to 11.5 mmol / g The ester group concentration is preferably 9.5 to 11.0 mmol / g, and more preferably 9.5 to 11.0 mmol / g. If the adhesive strength is too high, the polarity of the polyester resins (i) and (i') will decrease, resulting in poor initial adhesion and thinness. The film adhesion tends to be poor.

[0048] The ester bond concentration (mmol / g) is the concentration of the polyester resins (i) and (i') The number of moles of ester bonds in g is calculated from the amount of This calculation method is based on the number of moles of polycarboxylic acid (a) and polyol component (b) charged. This is the value obtained by dividing the smaller number of moles by the total weight of the finished product, and an example calculation formula is shown below. In addition, when the charged amounts of the polycarboxylic acid (a) and the polyol component (b) are equal in moles, Either of the following formulas may be used: In addition, monomers with both carboxylic acid and hydroxyl groups are used, and caprolactone is also used. When producing polyester from tons, the calculation method will need to be changed appropriately.

[0049] <When the amount of polycarboxylic acids (a) is small> Ester bond concentration (mmol / g) = [(A1 / α1 × m1 + A2 / α2 × m2 + A3 / α3×m3···) / Z×1000 A: Amount of polycarboxylic acid (a) (g) α: Molecular weight of polycarboxylic acid (a) m: number of carboxyl groups per molecule of polycarboxylic acid (a) Z: Finished weight (g) <When the amount of polyol component (b) is small> Ester group concentration (mmol / g) = [(B1 / β1 × n1 + B2 / β2 × n2 + B3 / β3×n3···) / Z×1000 B: Amount of polyol component (b) charged (g) β: Molecular weight of polyol component (b) n: number of hydroxyl groups per molecule of polyol component (b) Z: Finished weight (g)

[0050] The ester bond concentrations of the polyester resins (i) and (i') can be determined by using NMR or the like. A known method, for example, a resonance frequency of 400 MHz 1 H-NMR measurement (proton type nuclear magnetic resonance) resonance spectroscopy), 13 Also determined by C-NMR measurement (carbon-type nuclear magnetic resonance spectroscopy) It is possible.

[0051] As a method for adjusting the ester bond concentration to a predetermined range, for example, b) is a polyol having 4 or less carbon atoms, or Increase the content of straight-chain carboxylic acids with 8 or less carbon atoms, or dicarboxylic acids with even fewer carbon atoms. Examples of methods include increasing the amount of carboxylic acid, or combining both.

[0052] The glass transition temperature (Tg) of the polyester resins (i) and (i') is preferably - The temperature is preferably 70 to -10°C, more preferably -50 to -15°C, and even more preferably -4 5 to -20°C. If the glass transition temperature (Tg) is too high, the adhesive strength of the thin film will decrease. If the temperature is too low, the heat resistance and cohesive strength tend to decrease. In order to adjust the glass transition temperature, for example, an aromatic skeleton may be introduced or a polyvalent carboxylic acid may be introduced. Examples of such methods include changing the alkyl chain length of the acid (a) or the polyol component (b).

[0053] The glass transition temperature (Tg) was measured using a differential scanning calorimeter (DSC) manufactured by TA Instruments. It is measured using Q20. The measurement temperature range is -90 to 100°C. The temperature rise rate is 10°C / min.

[0054] The weight average molecular weight of the polyester resins (i) and (i') is preferably 2000 to 500,000, more preferably 5,000 to 200,000, particularly preferably 50,000 to If the weight average molecular weight is too large, the handling property will decrease. A large amount of solvent is required, which tends to increase the environmental load, and the weight average molecular weight is too small. If the adhesive is too thick, the adhesive properties tend to decrease.

[0055] The weight average molecular weight is calculated based on the molecular weight of standard polystyrene. A high-performance liquid chromatograph (Tosoh Corporation, "HLC-8320GPC") was used, and the column was TS. Kgel SuperMultipore HZ-M (exclusion limit molecular weight: 2×10 6 ,theory Number of stages: 16,000 stages / unit, Filler material: styrene-divinylbenzene copolymer, filler granules The measurement is performed using two 4 μm diameter probes connected in series.

[0056] The acid value of the polyester resins (i) and (i') is 10 mgKOH / g or less. is preferable in terms of preventing hydrolysis and increasing durability, and more preferably 5 mgKOH / g Preferably not more than 2 mgKOH / g, more preferably not more than 1 mgKOH / g, most preferably not more than 1 mgKOH / g. The acid value is preferably 0.5 mgKOH / g or less. If the acid value is too high, durability will decrease. There is a tendency to In order to adjust the acid value, for example, the poly(ethylene glycol) copolymer may be used during the esterification reaction or the transesterification reaction. Examples of such methods include increasing the ratio of the all component (b) and adjusting the reaction conditions. The lower limit of the acid value is usually 0 mg KOH / g.

[0057] The acid values ​​of the polyester resins (i) and (i') are determined based on the neutralization standard of JIS K0070. It is determined by titration. The acid value in the present invention is the carboxyl value of the polyester resins (i) and (i'). The carboxyl group refers to the content of carboxyl groups. Neutralized carboxylate ion forms are also included.

[0058] The results of the polyester resins (i) and (i') measured by a differential scanning calorimeter (DSC) are as follows: The heat of fusion of the crystal is preferably 10 J / g or less, more preferably 5 J / g or less, and even more preferably Preferably, the heat of fusion is 2 J / g or less, and particularly preferably, no heat of fusion occurs. If the heat is too great, crystallization will occur, which will result in poor storage stability of the resin solution and may cause problems with the adhesive sheet. However, the stability at low temperatures and adhesive strength at thin films tend to be poor.

[0059] As a method for adjusting the heat of fusion of crystals to a predetermined range, for example, Use polycarboxylic acids (a) and polyol components (b) with alkyl groups on the side chains as appropriate. and a method using three or more copolymerizable monomer components, preferably four or more copolymerizable monomer components. can be done.

[0060] The heat of fusion of crystals is the energy consumed when heating and melting a crystallized substance. , can be measured by differential scanning calorimetry (DSC).

[0061] The pressure-sensitive adhesive composition used in the present invention contains, in addition to the polyester resin (i) or (i'), , crosslinking agent (ii), hydrolysis inhibitor (iii), urethanization catalyst (iv) and antioxidant (v ) is preferably contained.

[0062] [Crosslinking agent (ii)] The pressure-sensitive adhesive composition used in the present invention preferably contains a crosslinking agent (ii). By incorporating the crosslinking agent (ii), the polyester resins (i) and (i') are crosslinked with the crosslinking agent (ii). This results in excellent cohesive strength, and the performance as an adhesive can be improved.

[0063] Examples of such crosslinking agents (ii) include isocyanate-based crosslinking agents (ii-1), polyepoxide-based crosslinking agents (ii-2), and the like. The hydroxyl and carboxyl groups contained in the polyester resins (i) and (i') are removed by the hydroxyl crosslinking agent. A crosslinking agent having a functional group that reacts with at least one of the hydroxyl groups is also included. Polyfunctional acrylic monomers or the like that increase the cohesive strength without reacting with the acrylic resin (i) are also used. Urethane acrylate oligomers can also be used. Isocyanate crosslinking agents are particularly popular because they offer a good balance of performance, mechanical strength, and heat resistance. It is preferable to use (ii-1).

[0064] Examples of such isocyanate-based crosslinking agents (ii-1) include tetramethylene diisocyanate. Anate, hexamethylene diisocyanate, isophorone diisocyanate, tolylene Isocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate Anate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethyl Xylylene diisocyanate, 1,5-naphthalene diisocyanate, triphenyl methane triisocyanate, and the like. Adducts of an anate and a polyol compound such as trimethylolpropane, and Examples include biuret and isocyanurate forms of reisocyanate compounds. The polyisocyanate compounds are phenols, lactams, etc., in which the isocyanate moiety is Blocked isocyanate crosslinking agents can also be used. 1) may be used alone or in combination of two or more.

[0065] In the isocyanate-based crosslinking agent (ii-1), an aromatic polyisocyanate-based compound Furthermore, the use of a trifunctional aromatic isocyanate compound is preferable. This is preferred because it has good compatibility with the ester resins (i) and (i').

[0066] The content of the crosslinking agent (ii) depends on the molecular weight of the polyester resins (i) and (i') and the intended use. Although it can be appropriately selected depending on the purpose, it is usually contained in the polyester resins (i) and (i'). per equivalent of at least one of the hydroxyl group and the carboxyl group contained in the crosslinking agent (ii), It is preferable that the crosslinking agent (ii) is contained in an amount of 0.2 to 10 equivalents of the reactive group, and particularly Preferably, the amount is 0.5 to 5 equivalents, more preferably 0.8 to 4 equivalents, and particularly preferably 1.1 to 3 equivalents. If the number of equivalents of the reactive groups contained in the crosslinking agent (ii) is too small, the cohesive strength will decrease. If it is too large, flexibility tends to decrease.

[0067] The content of the crosslinking agent (ii) is 100 times that of the polyester resins (i) and (i'). The amount is preferably 0.01 to 10 parts by weight, particularly preferably 0.1 to 8 parts by weight, Further, it is preferably 0.5 to 6 parts by weight, and particularly preferably 1 to 4 parts by weight. If the content of the agent is too low, the cohesive strength tends to decrease, and if the content is too high, the flexibility decreases. As a result, the required adhesive strength tends to be lost.

[0068] In addition, in the reaction between the polyester resins (i) and (i') and the crosslinking agent (ii), Organic solvents that do not have functional groups that react with these components, such as ethyl acetate, butyl acetate, etc. esters, ketones such as methyl ethyl ketone and methyl isobutyl ketone, toluene, These may be used alone or in combination of two or more. They can be used in combination.

[0069] <Hydrolysis inhibitor (iii)> The hydrolysis inhibitor (iii) is not particularly limited, and may be any of the conventionally known ones. For example, the carboxylic acid of the polyester resin (i) or (i') can be used. Examples include compounds that react with terminal groups to bond, such as carbodiimide groups and epoxy groups. Among these, compounds having functional groups such as a carboxyl group and an oxazoline group are particularly preferred. The carboxyl group-containing compound eliminates the catalytic activity of the protons derived from the carboxyl end group. This is preferable in that it has a high effect.

[0070] The carbodiimide group-containing compound used in the present invention is usually a compound having a carbodiimide group ( Any known carbodiimide having one or more -N=C=N- groups in the molecule can be used. However, in order to improve durability under high temperature and humidity conditions, it is preferable to use a polymer containing two or more carbodiimide groups in the molecule. It is preferable to use a compound having a polyvalent carbodiimide structure, that is, a polyvalent carbodiimide compound, and particularly a carbodiimide compound. It is a compound containing 3 or more, preferably 5 or more, and especially 7 or more imide groups in the molecule. It is preferable. The number of carbodiimide groups in a molecule is usually 50 or less. If there are too many groups, the molecular structure becomes too large, which tends to reduce compatibility.

[0071] The carbodiimide group-containing compound used in the present invention is preferably a compound having a weight average molecular weight of 100 or more and a molecular weight of 100 or more, from the viewpoint of hydrolysis resistance. It is preferable to use a compound having a high weight average molecular weight. The amount is preferably 1000 or more, more preferably 2000 or more, and The upper limit of the weight average molecular weight is usually 50,000. is.

[0072] Furthermore, it is preferable that the carbodiimide group-containing compound has low volatility. It is preferable to use one having a high number average molecular weight, usually 300 to 10,000, preferably It is between 1000 and 5000.

[0073] If the molecular weight of the carbodiimide group-containing compound is too small, the hydrolysis resistance tends to decrease. If the molecular weight is too large, the compatibility with the polyester resins (i) and (i') becomes poor. There is a tendency for it to decrease.

[0074] The carbodiimide equivalent of the carbodiimide group-containing compound is preferably 50 to 1000 0, particularly preferably 100 to 1000, and further preferably 150 to 500. The carbodiimide equivalent weight refers to the chemical formula weight per carbodiimide group.

[0075] Furthermore, the carbodiimide group-containing compound is a diisopropyl ether in the presence of a carbodiimide catalyst. Polycarbodiimide compounds produced by decarboxylation condensation of cyanates It is also preferable to use

[0076] [Polycarbodiimide Compounds] Polycarbodiimide compounds are produced by condensing organic diisocyanate compounds. You can get more. Examples of the organic diisocyanate compound include 1,5-naphthylene diisocyanate. 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethanate Diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate cyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, Mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, Aromatic diisocyanates such as silylene diisocyanate and tetramethylxylylene diisocyanate cyanate compounds; Acyclic aliphatic diisocyanates such as hexamethylene diisocyanate, cyclohexane -1,4-Diisocyanate, isophorone diisocyanate, dicyclohexylmethane- 4,4'-Diisocyanate, Methylcyclohexanediisocyanate, 2,5(2,6 )-bis(isocyanatomethyl)bicyclo[2.2.1]heptane and other alicyclic diisocyanates These may be used alone or in combination. The above may be used in combination. Among these, aromatic diisocyanates are preferred because they can provide pressure-sensitive adhesive compositions with excellent resistance to moist heat. Preferred are tetramethyl xylene diisocyanate compounds, and more preferred is tetramethyl xylene diisocyanate.

[0077] The organic diisocyanate compound is decarboximed in a conventional manner using a known carbodiimide catalyst. By carrying out an acid condensation reaction, a polycarbodiimide compound can be obtained.

[0078] The polycarbodiimide compound has little change in haze even under high temperature and high humidity conditions, and is moisture resistant. It is preferable that the compound be an aromatic polycarbodiimide compound because it can be used as an adhesive with excellent thermal properties. It is preferable that:

[0079] Furthermore, the polycarbodiimide compound used in the present invention is At least one of the terminal isocyanate groups is substituted with a substituent derived from a hydrophilic organic compound. It is preferable that:

[0080] [At least one of the terminal isocyanate groups of the polycarbodiimide compound is a hydrophilic organic compound. substituted with a substituent derived from a compound Next, at least one of the terminal isocyanate groups of the polycarbodiimide compound is hydrophilic. The following describes those substituted with substituents derived from organic compounds. First, the hydrophilic organic compound will be described.

[0081] [Hydrophilic organic compound] The hydrophilic organic compound is a compound having an isocyanate group at the end of the polycarbodiimide compound. The compound has a substituent having an active hydrogen that is reactive with the group, and in addition to the above substituent, further contains a hetero atom in the molecule. A compound that has one or more heteroatoms.

[0082] Examples of the substituent having an active hydrogen reactive with the isocyanate group include: Acid group, primary amino group, secondary amino group, imino group, isocyanate group, carboxy group, etc. Among these, a hydroxyl group, a primary amino group, a secondary amino group, and an imino group are preferred. These substituents may be contained alone or in combination of two or more in the hydrophilic organic compound. .

[0083] The number of substituents having active hydrogen reactive with the isocyanate group is determined by the hydrophilic organic compound. The number of the substituents in the compound is usually 2 or less, and preferably 1. It is preferably located at the end of the compound.

[0084] The compound has a substituent having an active hydrogen that is reactive with the isocyanate group, and Other compounds having one or more heteroatoms in the molecule include, for example, oxyalkylenes. Compounds containing ethylene structure, compounds containing hydroxypolyester structure, hydroxyalkyl sulfur compounds containing carboxylic acid structure, compounds containing dialkylamino alcohol structure, hydroxycarbo Compounds containing alkyl phosphate ester structure, compounds containing dialkylaminoalkylamine structure Among these, compounds containing an oxyalkylene structure are preferred.

[0085] The ends of the hydrophilic organic compounds are blocked with alkoxy groups or phenoxy groups. It is preferable.

[0086] Among these, hydrophilic organic compounds are those having an alkoxy group or a phenoxy group at the end. The compound containing an end-blocked oxyalkylene structure maintains its hygroscopicity even under high temperature and high humidity conditions. This is preferable in that the change in width is small.

[0087] The compound containing an oxyalkylene structure end-blocked with an alkoxy group or a phenoxy group Examples of the substance include a compound represented by the following formula (1). R1-O-(CH2-CHR2-O)mH (1) In the above formula (1), R1 represents an alkyl group having 1 to 4 carbon atoms or a phenyl group, and R2 represents a hydrogen atom. It represents an atom or a methyl group, and m is an integer of 4 to 100.

[0088] Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, Examples include an isopropyl group, an n-butyl group, an s-butyl group, an isobutyl group, and a t-butyl group. can be.

[0089] Specific examples of the compound represented by the above formula (1) include polyethylene glycol monomethyl Ether, polyethylene glycol monoethyl ether, polypropylene glycol mono Methyl ether, polypropylene glycol monoethyl ether, polypropylene glycol Among them, polyethylene glycol monomethyl ether and the like are particularly preferred. Diethers are preferred.

[0090] The weight average molecular weight of the hydrophilic organic compound is preferably 200 or more, and more preferably 40 0 or more is more preferable. The upper limit of the weight average molecular weight is usually 5000 or less, Preferably 4000 or less, more preferably 2000 or less, and even more preferably 1000 or less If the weight average molecular weight is too small, the compatibility with the polyester resin decreases, and Furthermore, the change in haze tends to be greater under high temperature and high humidity conditions. If it is too thick, the adhesive strength tends to decrease.

[0091] At least one of the terminal isocyanate groups of the polycarbodiimide compound is a hydrophilic The polycarbodiimide-based compound and the parent compound are substituted with substituents derived from organic compounds. It can be obtained by reacting with an aqueous organic compound.

[0092] The reaction between the polycarbodiimide compound and the hydrophilic organic compound is a polycarbodiimide The compound is heated to a temperature of usually 50 to 200°C, preferably 100 to 180°C, and then the above hydrophilic An organic compound is added, and the reaction is continued at 80 to 200°C for 0.5 to 5 hours.

[0093] In this way, at least one of the terminal isocyanate groups of the polycarbodiimide compound is One of the compounds is substituted with a substituent derived from a hydrophilic organic compound.

[0094] Commercially available polycarbodiimide compounds include, for example, Carbodiimide manufactured by Nisshinbo Chemical Co., Ltd. Zylight (registered trademark) V-09GB, V-02B, V-04K, V-04PF, V-07 BASF's Elastostab H01, and among them, Carbodilite V -09GB is preferred.

[0095] Examples of the epoxy group-containing compound include glycidyl ester compounds and glycidyl Ether compounds and the like are preferred.

[0096] Examples of the glycidyl ester compound include benzoic acid glycidyl ester, t- Bu-benzoic acid glycidyl ester, p-toluic acid glycidyl ester, cyclohexa Glycidyl ester of carboxylic acid, glycidyl ester of pelargonic acid, glycidyl ester of stearate Glycidyl ester, lauric acid glycidyl ester, palmitic acid glycidyl ester, behen Glycidyl ester of carboxylic acid, glycidyl ester of versatic acid, glycidyl ester of oleic acid ester, linoleic acid glycidyl ester, linolenic acid glycidyl ester, behenol Acid glycidyl ester, stearolic acid glycidyl ester, diglycidyl terephthalate Ester, isophthalic acid diglycidyl ester, phthalic acid diglycidyl ester, naphtha Diglycidyl ester of diphenyl ether, diglycidyl ester of methyl terephthalic acid, Hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester , cyclohexanedicarboxylic acid diglycidyl ester, adipic acid diglycidyl ester , succinic acid diglycidyl ester, sebacic acid diglycidyl ester, dodecanedioic acid Diglycidyl ester, Octadecanedicarboxylic acid diglycidyl ester, Trimelli acid triglycidyl ester, pyromellitic acid tetraglycidyl ester, etc. These can be used alone or in combination of two or more.

[0097] Examples of the glycidyl ether compound include phenyl glycidyl ether, o- Phenyl glycidyl ether, 1,4-bis(β,γ-epoxypropoxy)butane, 1 ,6-bis(β,γ-epoxypropoxy)hexane, 1,4-bis(β,γ-epoxy 1-(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-hydroxy Bisphenyls such as 2,2-bis-(4-hydroxyphenyl)propane and 2,2-bis-(4-hydroxyphenyl)methane Examples include bisglycidyl polyether obtained by the reaction of glycerol with epichlorohydrin. These may be used alone or in combination of two or more.

[0098] The oxazoline group-containing compound is preferably a bisoxazoline 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-phenylene 2,2'-p-phenylenebis(4,4-diphenyl ether) methyl-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'-octamethylene 2,2'-decamethylenebis(2-oxazoline), 2, 2'-ethylenebis(4-methyl-2-oxazoline), 2,2'-tetramethylenebis( 4,4-dimethyl-2-oxazoline), 2,2'-9,9'-diphenoxyethane bis( 2-oxazoline), 2,2'-cyclohexylenebis(2-oxazoline), 2,2'- Examples include diphenylenebis(2-oxazoline), and among these, 2, 2'-bis(2-oxazoline) is most preferred in terms of reactivity with polyester. Furthermore, the above-mentioned bisoxazoline compounds may be used alone as long as they achieve the object of the present invention. They can be used alone or in combination of two or more.

[0099] The hydrolysis inhibitor (iii) is preferably low in volatility, and therefore, the molecular weight It is preferable to use a higher amount.

[0100] The amount of the hydrolysis inhibitor (iii) to be added is determined based on the ratio of the polyester resins (i) and (i') to 1. It is preferably 0.01 to 10 parts by weight, and particularly preferably 0. The amount is preferably 1 to 5 parts by weight, more preferably 0.2 to 3 parts by weight. Poor compatibility with polyester resins (i) and (i') tends to cause turbidity. If the amount is too small, it tends to be difficult to obtain sufficient durability.

[0101] The amount of the hydrolysis inhibitor (iii) to be added is determined by the ratio of the polyester resin (i), (i It is preferable to optimize the blending amount depending on the acid value of polyester in the pressure-sensitive adhesive composition. The sum (α) of the acid values ​​of the ether resins (i) and the function of the hydrolysis inhibitor (iii) in the pressure-sensitive adhesive composition The molar ratio ((β) / (α)) of the total amount of functional groups (β) is 0.5≦(β) / (α). It is particularly preferable that 1≦(β) / (α)≦1000, and further preferably 1.5≦ (β) / (α)≦100. If the content ratio of (β) to (α) is too high, the polyester resins (i) and (i') The compatibility of (α) tends to decrease, and adhesive strength, cohesive strength, and durability tend to decrease. When the content of (β) is low, the moisture and heat resistance tends to decrease.

[0102] [Urethanization catalyst (iv)] The pressure-sensitive adhesive composition used in the present invention contains a urethane catalyst (iv) from the viewpoint of reaction rate. It is more preferable that

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

[0104] Examples of the organometallic compounds include zirconium compounds, iron compounds, tin compounds, and the like. Examples of compounds include titanium compounds, lead compounds, cobalt compounds, and zinc compounds. can.

[0105] Examples of the zirconium compounds include zirconium naphthenate, zirconium Acetylacetonate and the like. Examples of the iron-based compound include iron acetylacetonate and iron 2-ethylhexanoate. etc. Examples of the tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin nitrite ... butyltin dilaurate and the like. Examples of the titanium compounds include dibutyltitanium dichloride, tetrabutyltitanium dichloride, Examples of suitable amines include butoxytitanium trichloride, butoxytitanium trichloride, and the like. Examples of the lead-based compounds include lead oleate, lead 2-ethylhexanoate, and lead benzoate. Examples include lead and lead naphthenate. Examples of the cobalt-based compounds include cobalt 2-ethylhexanoate and cobalt benzoate. Barth et al. Examples of the zinc compounds include zinc naphthenate and zinc 2-ethylhexanoate. Examples include:

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

[0107] Among these urethane catalysts (iv), the following are preferred in terms of reaction rate and pot life of the adhesive layer: Organometallic compounds are preferred, and zirconium compounds are particularly preferred. Catalyst (iv) is preferably used in combination with acetylacetone as a catalytic inhibitor. The inclusion of diacetone inhibits catalytic activity at low temperatures and extends the pot life. preferable.

[0108] The content of the urethane catalyst (iv) is 100 times that of the polyester resins (i) and (i'). The amount is preferably 0.0001 to 1 part by weight, particularly preferably 0.001 to 0.1 It is preferable that the content is 0.01 to 0.05 parts by weight. If it is too much, the aging time until the crosslinking reaction is completed tends to be long, and if it is too much, the adhesive properties will be deteriorated. tends to decrease.

[0109] [Antioxidants (v)] The pressure-sensitive adhesive composition used in the present invention contains an antioxidant (v) in order to improve the stability of the resin. It is more preferable to have

[0110] Examples of the antioxidant (v) include hindered phenol-based antioxidants, amines, and the like. Antioxidants based on hydroxyl groups, sulfur-based antioxidants, and phosphoric acid-based antioxidants are examples of such antioxidants. The antioxidant is selected from the group consisting of a phenolic antioxidant, an amine antioxidant, and a phosphoric acid antioxidant. It is preferable that the compound is at least one of the above, and in particular, a compound consisting of a hindered phenol compound. Antioxidants containing hydroxybenzoates are preferred.

[0111] Examples of hindered phenol antioxidants include those in which a phenolic hydroxyl group is bonded. At least one of the carbon atoms adjacent to the carbon atom on the aromatic ring has a tertiary butyl group or the like. Antioxidants that have a hindered phenol structure with a large, hindered group attached include .

[0112] The content of the antioxidant (v) is 100 parts by weight of the polyester resins (i) and (i'). The amount is preferably 0.01 to 10 parts by weight, and more preferably 0.03 to 8 parts by weight. If the content is too small, the adhesive may be irritated to the adherend. If the amount is too large, adhesive properties tend to decrease.

[0113] In the pressure-sensitive adhesive composition used in the present invention, the polyester resin (i) or (i '), crosslinking agent (ii), hydrolysis inhibitor (iii), urethanization catalyst (iv), antioxidant (v ), but also in a range that does not impair the effects of the present invention (for example, 10% by weight or less of the pressure-sensitive adhesive composition). In the process, additives such as tackifier resins, softeners, UV absorbers, stabilizers, antistatic agents, etc. In addition, inorganic or organic fillers, metal powders, pigments, and other powders and particulate additives can be added. These can be used alone or in combination of two or more. It may contain small amounts of impurities contained in the raw materials for producing the constituent components of the composition. .

[0114] The pressure-sensitive adhesive composition may comprise, for example, the polyester resin (i) or (i'), and Necessary optional ingredients are prepared and mixed and dispersed during the production of polyester resin (i). or by mixing with polyester resin (i) or (i') At this time, it can be obtained by dispersing it in a solvent. It may be dispersed in water or without solvent. The main component is preferably 50% by weight or more, more preferably 70% by weight or more, and even more preferably 10% by weight or more. The content is preferably 80% by weight or more, and particularly preferably 90% by weight or more. If the fat content is low, the heat resistance tends to be poor.

[0115] <Adhesive layer> The pressure-sensitive adhesive layer of the present invention is obtained by crosslinking (curing) the pressure-sensitive adhesive composition. The adhesive layer can be obtained by coating and drying a pressure-sensitive adhesive composition. This will be described in detail in the sheet manufacturing method.

[0116] The pressure-sensitive adhesive layer of the present invention has a thickness of 18 μm or less, preferably 15 μm or less, more preferably It is preferably 12 μm or less, more preferably 8 μm or less, and particularly preferably 3 μm or less. The limit is usually 0.1 μm. Generally, the thicker the adhesive layer, the stronger the adhesive strength. However, the pressure-sensitive adhesive layer of the present invention has good adhesion to various adherends despite its thin thickness. It has excellent adhesive strength.

[0117] The thickness of the adhesive layer was measured using a Digimatic Indicator (Mitutoyo Corporation, ID-C1 12B). In the case of adhesive sheets, which will be described later, The thickness of the adhesive sheet as a whole is measured by subtracting the thickness of the components other than the adhesive layer. It can be calculated by:

[0118] The gel fraction of the pressure-sensitive adhesive layer is preferably 10% by weight or more from the viewpoint of durability and adhesive strength. It is particularly preferable that the content is 15 to 80% by weight, and further preferably 20 to 70% by weight. In particular, it is 30 to 55% by weight, and most preferably 35 to 45% by weight. The cohesive force decreases, which tends to decrease durability. There is a concern that the increased cohesive force will result in a decrease in adhesive strength.

[0119] The gel fraction is a measure of the degree of crosslinking and is calculated, for example, by the following method. That is, the adhesive layer was wrapped in a 200-mesh SUS wire netting and immersed in toluene at 23°C for 24 hours. The weight of the undissolved adhesive remaining in the wire mesh after immersion was calculated based on the weight of the adhesive component before immersion. The weight percentage of the agent component is taken as the gel fraction.

[0120] <Adhesive sheet> The pressure-sensitive adhesive sheet of the present invention has the pressure-sensitive adhesive layer. A first aspect of the pressure-sensitive adhesive sheet of the present invention comprises the pressure-sensitive adhesive layer and a substrate, The above-mentioned substrate is laminated on one side, and a release-treated sheet is on the other side. A second aspect of the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer and a release-treated sheet. The release-treated sheets are laminated on both sides of the pressure-sensitive adhesive layer. That is, the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on one or both sides of a supporting substrate. It may be a double-sided adhesive sheet with no substrate, or a substrate-less type double-sided adhesive sheet with no substrate. It's okay to have it. In the present invention, the term "sheet" includes "film" and "tape." do.

[0121] The method for producing the pressure-sensitive adhesive sheet of the first embodiment can be the same as a known general method for producing a pressure-sensitive adhesive sheet. Therefore, the pressure-sensitive adhesive sheet can be produced by, for example, applying the pressure-sensitive adhesive composition to one surface of a substrate and drying the composition. A pressure-sensitive adhesive layer is formed by applying a release-treated sheet to the surface (the surface opposite to the surface that contacts the substrate). The laminate is then laminated together and cured as necessary to obtain the desired product.

[0122] Alternatively, the pressure-sensitive adhesive composition is applied to the release-treated sheet, followed by drying to form a pressure-sensitive adhesive layer. A layer is formed, and a substrate is attached to the surface (the surface opposite to the surface that comes into contact with the release-treated sheet), and if necessary This can be obtained by curing the material.

[0123] Examples of the substrate include polyethylene naphthate, polyethylene terephthalate, Polybutylene terephthalate, polyethylene terephthalate / isophthalate copolymer, etc. Polyester resins such as polyethylene, polypropylene, polymethylpentene, etc. olefin resins; polyvinyl fluoride, polyvinylidene fluoride, polyethylene fluoride, etc. Fluorinated ethylene resin; nylon 6, nylon 6,6 and other polyamides; polyvinyl chloride, Polyvinyl chloride / vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl vinyl alcohol copolymers, polyvinyl alcohol, vinylon and other vinyl polymers; triacetic acid cellulose Cellulose resins such as cellulose and cellophane; polymethyl methacrylate, polymethacrylic acid Acrylic resins such as polyethyl acrylate, polyethyl acrylate, polybutyl acrylate, etc.; Polycarbonate; Polyarylate; Polyimide; Cycloolefin polymer, etc. Synthetic resin sheets; metal foils such as aluminum, copper, iron, etc.; paper such as fine paper and glassine paper; Examples include woven fabrics and nonwoven fabrics made of lath fiber, natural fiber, synthetic fiber, etc. An ester-based resin sheet is preferred, and polyethylene terephthalate is more preferred.

[0124] As the release-treated sheet, for example, the above-mentioned substrate may be subjected to release treatment. Among these, it is preferable to use a silicone-based release sheet.

[0125] The pressure-sensitive adhesive composition can be applied by, for example, a gravure roll coater or a reverse roll coater. Roll coater, kiss roll coater, dip roll coater, bar coater, knife coater A coater, spray coater, comma coater, or the like may be used.

[0126] The drying conditions after coating the pressure-sensitive adhesive composition are as follows: drying temperature: 60 to 140°C The drying temperature is preferably 80 to 120°C, and the drying time is preferably 0.5 to 30 minutes. is preferable, and 1 to 5 minutes is particularly preferable.

[0127] The conditions for the above curing treatment are usually room temperature (23°C) to 70°C, and the time is usually 1 to 2 hours. Specifically, for example, at 23°C for 1 to 20 days, preferably at 23°C for 3 to 1 The incubation may be carried out under conditions such as 4 days at 40°C for 1 to 10 days.

[0128] The manufacturing method of the pressure-sensitive adhesive sheet of the second embodiment can also be performed according to a known general manufacturing method of a pressure-sensitive adhesive sheet. For example, the pressure-sensitive adhesive composition can be applied to a release-treated sheet and then dried. Then, a pressure-sensitive adhesive layer is formed, and the release agent is applied to the surface (the surface opposite to the surface that contacts the release-treated sheet). The adhesive sheet of the second embodiment is obtained by laminating a release-treated sheet other than the molded sheet. The release-treated sheet used in the second embodiment is the same as that used in the first embodiment. The coating method, drying conditions, and curing conditions can also be specified. This can be done in accordance with the first embodiment.

[0129] When using the obtained pressure-sensitive adhesive sheet or substrate-less double-sided pressure-sensitive adhesive sheet, the sheet is subjected to the above-mentioned release treatment. The adhesive is peeled off from the adhesive layer, and the adhesive layer is then stuck to the adherend.

[0130] The adhesive sheet of the present invention has an adhesive strength of 5 N / 25 mm or more when measured under the following measurement conditions: It is preferable that the tension is 6N / 25mm or more, and more preferable that the tension is 7N / 25mm or more. The upper limit is not particularly limited, but is usually 100 N / 25 mm. [Adhesive strength (N / 25mm) measurement conditions] The adhesive sheet was cut into 25mm x 200mm pieces under an environment of 23°C and 50% RH, and then released. The film was peeled off, and the adhesive layer side was placed on a SUS-BA plate as the adherend, and a 2 kg load was applied. Then, after leaving it in the same atmosphere for 30 minutes, A rough (Shimadzu Corporation, Autograph AGS-H 500N) was used at a peeling speed of 300 The 180-degree peel strength (N / 25 mm) measured in mm / min was used as the adhesive strength. The above SUS-BA plate is made by cold rolling SUS304 and then bright annealing (non-oxidizing annealing). This refers to steel that has undergone skin pass rolling to enhance gloss.

[0131] The pressure-sensitive adhesive sheet of the present invention has an adhesive strength (N / 25 mm) measured under the above measurement conditions. When X is the thickness (μm) of the adhesive layer and Y is the thickness (μm) of the adhesive layer, it is preferable that X / Y≧0.5, and It is more preferably 1.0, and especially preferably ≧1.5.

[0132] The pressure-sensitive adhesive sheet of the present invention has an adhesive strength over time of 5 N / 25 mm or more measured under the following measurement conditions. It is preferable that the load is 6N / 25mm or more, more preferable that the load is 7N / 25mm or more. The upper limit is not particularly limited, but is usually 100N / 25mm. do. [Measurement conditions for adhesive strength over time (N / 25mm)] The adhesive sheet was cut into 25mm x 200mm pieces under an environment of 23°C and 50% RH, and then the adhesive was The adhesive layer is placed against a SUS-BA plate as the adherend, and a 2 kg roller is moved back and forth to apply pressure. After leaving it to stand for 24 hours under the same atmosphere, the sample was analyzed by an autograph (Shimadzu Corporation, The peel rate was measured at 300 mm / min using a graph AGS-H 500N. The adhesive strength is the 80 degree peel strength (N / 25mm). The above SUS-BA plate is made by cold rolling SUS304 and then bright annealing (non-oxidizing annealing). This refers to steel that has undergone skin pass rolling to enhance gloss.

[0133] The pressure-sensitive adhesive sheet of the present invention has an adhesive strength over time (N / 25 mm) measured under the above measurement conditions. ) is Z and the thickness (μm) of the adhesive layer is Y, it is preferable that Z / Y≧1.0. , more preferably Z / Y≧2.0, and particularly preferably Z / Y≧3.0. .

[0134] The pressure-sensitive adhesive sheet of the present invention can be used to bond various members, and in particular, Single-sided or double-sided adhesive sheets for imide, single-sided or double-sided adhesive sheets for bonding optical components adhesive sheets, single-sided or double-sided adhesive sheets for fixing components in portable electronic devices, and electronic components It is preferably used for: [Example]

[0135] The present invention will be explained in more detail below with reference to examples, but the present invention will not go beyond the gist of the invention. The present invention is not limited to the following examples unless otherwise specified. It means by weight.

[0136] In the following examples, the ester bond concentration and glass transition temperature of the polyester resin are Regarding the measurement of the weight average molecular weight, acid value, heat of fusion of crystals, and gel fraction of the adhesive layer, the above-mentioned method is used. The measurements were carried out according to the method.

[0137] A polyester resin was produced by the following method.

[0138] [Production Example 1: Production of Polyester Resin (i-1)] A reactor equipped with a thermometer, a stirrer, a rectification column, a nitrogen inlet tube, and a vacuum device was charged with polyvalent carboxylic acid. As the acid (a), 46.2 parts of adipic acid, 13.1 parts of isophthalic acid, polyol component ( b) 13.1 parts ethylene glycol and 26.8 parts neopentyl glycol, 0.8 parts of trimethylolpropane, 0.01 parts of tetrabutyl titanate as a catalyst. The internal temperature was gradually increased to 250°C, and the esterification reaction was carried out over 4 hours. After that, the internal temperature was raised to 260°C, and 0.01 parts of tetrabutyl titanate was added as a catalyst. The pressure was reduced to 1.33 hPa, and the polymerization reaction was carried out for 3 hours to obtain a polyester resin (i-1 ) was manufactured. The composition (molar ratio) of the obtained polyester resin (i-1) was adipic acid / isophthalic acid. Acid / ethylene glycol / neopentyl glycol / trimethylolpropane = 80 / 2 The ester bond concentration was 10.0 mmol / g. The heat of fusion is 0 J / g, the weight average molecular weight is 78,000, and the glass transition temperature (Tg) is -30°C. The acid value was 0.1 mg KOH / g.

[0139] Production Examples 2 to 5 and Comparative Production Examples 1 and 2 were the same as Production Example 1 except that the resin compositions were as shown in Table 1 below. It was prepared in the same manner. The resin compositions and physical properties of the prepared polyester resins (i-1) to (i-7) are shown in Table 1 below. Shown below.

[0140] [Table 1]

[0141] Comparative Production Example 3: Production of acrylic resin (b-1) A four-necked round-bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer 5 parts acrylic acid, 65 parts butyl acrylate, 30 parts methyl acrylate and acetic acid 150 parts of ethyl acetate and 45 parts of acetone were charged, and after heating and refluxing, azobis(2,4-dimethylamino)propanol was added as a polymerization initiator. Add 0.03 parts of isobutyronitrile (AIBN) and let react for 3 hours at the reflux temperature of ethyl acetate. After the reaction, the mixture was diluted with ethyl acetate to give an acrylic resin (b-1) solution (weight average Molecular weight (Mw) 1.2 million, calculated using Fox's formula, glass transition temperature -35°C, solid content 25% The viscosity was 5,000 mPa·s (25°C).

[0142] Next, the following components were prepared. [Crosslinking agent (ii)] Isocyanate crosslinking agent (ii-1A): "Coronate L55E" (manufactured by Tosoh Corporation) Isocyanate crosslinking agent (ii-2A): "Coronate HX" (manufactured by Tosoh Corporation) [Hydrolysis inhibitor (iii)] Carbodiimide compounds (iii-1): Substituted at the end with aromatic monoisocyanates Aromatic polycarbodiimide compound substituted with a group, "Carbodilite V-09GB" ( Nisshinbo Chemical Co., Ltd.), weight average molecular weight: 6000 [Urethanization catalyst (iv)] Zirconium compounds (iv-1): "Orgatics ZC-150" (Matsumoto P. (manufactured by Benzene Chemical Co., Ltd.) diluted with acetylacetone to a solids concentration of 1% [Antioxidants (v)] Hindered phenolic antioxidant (v-1): "IRGANOX1010" (BAS (Made by F Company)

[0143] Next, the polyester resins (i-1) to (i-3) obtained above were used as follows: Pressure-sensitive adhesive compositions were prepared, and pressure-sensitive adhesive sheets of Examples and Comparative Examples were produced.

[0144] [Example 1] The polyester resin (i-1) obtained above was diluted with ethyl acetate to a solids concentration of 50%. 1.5 parts (solids) of an isocyanate-based crosslinking agent (ii-1A) was added to 100 parts of the solids. 0.5 parts (solids) of a carbodiimide compound (iii-1), and a zirconium compound (iv-1) 0.02 parts (solids), hindered phenolic antioxidant (v-1) 0.1 The components were blended, stirred and mixed to obtain a pressure-sensitive adhesive composition. The obtained adhesive composition was applied to polyethylene terephthalate (PET) sheets so that the thickness after drying was about 5 μm. After applying it to a polyethylene terephthalate (PET) film (thickness 38 μm), it was dried at 100°C for 1 minute. A pressure-sensitive adhesive layer was formed. After that, a release-treated PET sheet (release sheet) was attached to the pressure-sensitive adhesive layer. The surface was protected by a protective film, and the adhesive sheet was left to cure for 10 days in an atmosphere at 40°C. I got the point.

[0145] [Examples 2 to 8, Comparative Examples 1 to 4] A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the ingredients were blended as shown in Table 2 below. A pressure-sensitive adhesive sheet was obtained.

[0146] [Table 2]

[0147] [Examples 9 and 10, Comparative Example 5] In Example 1, the ingredients are blended as shown in Table 3 below, and the thickness of the adhesive layer after drying is 10 μm. A pressure-sensitive adhesive composition was prepared and a pressure-sensitive adhesive sheet was obtained in the same manner except for the above.

[0148] [Table 3]

[0149] [Examples 11 and 12, Comparative Examples 6 and 7] In Example 1, the composition was as shown in Table 4 below, and the thickness of the adhesive layer after drying was 2 μm. A pressure-sensitive adhesive composition was prepared and a pressure-sensitive adhesive sheet was obtained in the same manner as above, except for the above.

[0150] [Table 4]

[0151] The resulting pressure-sensitive adhesive sheets of the Examples and Comparative Examples were evaluated as follows. Since adhesive strength varies depending on the thickness of the layer, evaluation criteria are established according to the thickness of the adhesive layer. The results of Examples 1 to 8 and Comparative Examples 1 to 4, in which the thickness of the adhesive layer was 5 μm, are shown below. The results of Examples 9 and 10 and Comparative Example 5, in which the thickness of the adhesive layer was 10 μm, are shown in Table 5, and will be described later. Table 6 also shows the results of Examples 11 and 12 and Comparative Examples 6 and 7, in which the thickness of the adhesive layer is 2 μm. is shown in Table 7.

[0152] <Adhesion strength (peel strength) (to SUS)> A SUS-BA plate was prepared as the adherend. The pressure-sensitive adhesive sheet obtained above was heated at 23°C, 50% After cutting into 25mm x 200mm pieces under a RH environment, the release film was peeled off and the adhesive layer side The sheet was placed in contact with a SUS-BA plate and a 2 kg roller was moved back and forth to pressurize and adhere the sheet. After leaving it to stand for 30 minutes under atmospheric pressure, the sample was analyzed by an autograph (Shimadzu Corporation, Autograph AGS- H 500N) at a peel speed of 300 mm / min and a 180-degree peel strength (N / 25m m) was measured and evaluated according to the following criteria. SUS-BA plate is made by cold rolling SUS304 and then bright annealing (non-oxidizing annealing). This refers to steel that has been subjected to skin pass rolling to enhance gloss. (Evaluation criteria for adhesive layer thickness of 5 μm) 〇...7N / 25mm or more. △···5N / 25mm or more, less than 10N / 25mm. ×Less than 5N / 25mm. (Evaluation criteria: adhesive layer thickness 10 μm) 〇...12N / 25mm or more. ×Less than 12N / 25mm. (Evaluation criteria for adhesive layer thickness of 2 μm) 〇...5N / 25mm or more. ×Less than 5N / 25mm.

[0153] <Adhesive strength (peel strength) (against PI)> The substrate was polyimide (PI) (Toray DuPont, "Kapton", thickness 100 μm). The film was attached to a SUS-BA plate with double-sided tape to prepare a PI adherend. The adhesive sheet obtained in step 2 was cut into a size of 25 mm x 200 mm under an environment of 23°C and 50% RH. After that, peel off the release film, place the adhesive layer on the PI adherend, and roll a 2 kg roller back and forth. After leaving it in the same atmosphere for 30 minutes, it was then scanned using an autograph (Shimadzu A peeling speed of 300 mm / min was used with an Autograph AGS-H 500N manufactured by Seisakusho Co., Ltd. The 180-degree peel strength (N / 25 mm) was measured and evaluated according to the following criteria. (Evaluation criteria for adhesive layer thickness of 5 μm) 〇...13N / 25mm or more. △···10N / 25mm or more, less than 13N / 25mm. ×Less than 10N / 25mm. (Evaluation criteria: adhesive layer thickness 10 μm) 〇...15N / 25mm or more. ×Less than 15N / 25mm. (Evaluation criteria for adhesive layer thickness of 2 μm) 〇...5N / 25mm or more. ×Less than 5N / 25mm.

[0154] <Adhesive strength (peel strength) (against PP)> The substrate was a polypropylene plate (PP) (manufactured by Nippon Test Panel Co., Ltd., PP 2.0 x 70 The pressure-sensitive adhesive sheet obtained above was placed in an environment of 23°C and 50% RH. After cutting to 25mm x 200mm, peel off the release film and place the adhesive layer on the polypropylene sheet. The film was placed against a polypropylene (PP) plate and pressed with a 2 kg roller. After leaving the sample in an airtight container for 30 minutes, the sample was analyzed by an autograph (Shimadzu Corporation, Autograph AGS-H 500N) at a peel speed of 300mm / min and a 180-degree peel strength (N / 25mm ) was measured and evaluated according to the following criteria. (Evaluation criteria for adhesive layer thickness of 5 μm) 〇...5N / 25mm or more. △···1N / 25mm or more, less than 5N / 25mm. ×...Less than 1N / 25mm. (Evaluation criteria: adhesive layer thickness 10 μm) 〇...5N / 25mm or more. ×Less than 5N / 25mm.

[0155] <Adhesive strength over time (peel strength after 24 hours)> A SUS304-BA plate was prepared as the adherend. The pressure-sensitive adhesive sheet obtained above was heated at 23°C, After cutting into 25mm x 200mm pieces under a 50% RH environment, the release film was removed and the adhesive was applied. The adhesive layer side was placed in contact with a SUS-BA plate, and a 2 kg roller was moved back and forth to pressurize and adhere the adhesive. After leaving the sample in the same atmosphere for 24 hours, the sample was analyzed by an autograph (Shimadzu Corporation, Autograph A GS-H 500N) at a peel speed of 300 mm / min and 180-degree peel strength (N / 25mm) was measured. Moreover, Examples 11 and 12 and Comparative Examples 6 and 7 were evaluated according to the following criteria. (Evaluation criteria) 〇...5N / 25mm or more. ×Less than 5N / 25mm.

[0156] <Initial rate> The value of "adhesive strength (peel strength) (against SUS)" measured above is A, and "adhesive strength over time (24 hours)" is A. The initial ratio is higher than the initial value, and the value of "peel strength after application" is set to B. The adhesive strength is apparent from the beginning, and the performance is being realized in a meaningful way. (Evaluation criteria) 〇···More than 70%. ×Less than 70%.

[0157] <Holding force (cohesive force)> The pressure-sensitive adhesive sheets of Examples 1 to 8 and Comparative Examples 1 to 4 obtained above were subjected to a pressure-sensitive adhesive test in accordance with JIS Z-0237. The adhesive was applied to SUS304 with an area of ​​25mm x 25mm, and then heated to 80°C. After leaving it for 20 minutes, a 1 kg load is applied and the time until it falls is measured, or after leaving it for 24 hours For those that did not fall off after being placed on the floor, the condition was visually inspected after 24 hours and evaluated according to the following criteria: Ta. (Evaluation criteria) ○...It did not fall off even after being left standing for 24 hours. ×: It fell off after being left standing for 24 hours.

[0158] [Table 5]

[0159] [Table 6]

[0160] [Table 7]

[0161] From the above results, the structural moiety derived from polycarboxylic acids (a) is fatty acids having 8 or less carbon atoms. Pressure-sensitive adhesives of Examples 1 to 10 containing a specific amount or more of a structural moiety derived from aromatic dicarboxylic acids (a1) The adhesive layer (adhesive sheet) has excellent adhesive strength to various adherends even though it is thin, and it adheres well from the beginning. It was a powerful display of power. On the other hand, the comparative example does not contain a structural portion derived from the aliphatic dicarboxylic acids (a1) having 8 or less carbon atoms. The adhesive layers (adhesive sheets) of 1 to 5 have higher adhesive strength to various adherends than the adhesive layers of the examples. Furthermore, the initial rate is low and the adhesive strength is not fully exerted from the beginning. there were. The adhesive layers (adhesive sheets) of Examples 11 and 12 were very thin, at 2 μm. It also had excellent adhesive strength to various substrates, and the adhesive strength was fully demonstrated from the beginning. The adhesive of Comparative Example 6, which does not contain a structural portion derived from aliphatic dicarboxylic acids (a1) having 8 or less carbon atoms The adhesive layer (adhesive sheet) has a lower initial rate than the adhesive layer of the example, and has sufficient adhesive strength from the beginning. However, by using a polyester-based adhesive layer, Compared to Comparative Example 7, which used an acrylic adhesive layer, it was confirmed that the adhesive strength over time was superior. The Z / Y value using this adhesive strength over time is sufficiently high compared to acrylic resins. That was the case. In the above examples, specific embodiments of the present invention have been shown. The above is merely an example and is not intended to be limiting. are contemplated to be within the scope of the present invention. [Industrial Applicability]

[0162] The pressure-sensitive adhesive of the present invention has excellent effects even when it is thin, and is suitable for use as a polyimide sheet. Single-sided or double-sided adhesive sheets, single-sided or double-sided adhesive sheets used for bonding optical components, Used as single-sided or double-sided adhesive sheets for fixing components in portable electronic devices and electronic components. .

Claims

1. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer crosslinked with a pressure-sensitive adhesive composition containing a polyester resin (i') having a structural moiety derived from a polyvalent carboxylic acid (a) and a structural moiety derived from a polyol component (b), The thickness of the pressure-sensitive adhesive layer is 18 μm or less, A pressure-sensitive adhesive sheet characterized in that the adhesive strength over time measured under the following measurement conditions is 5 N / 25 mm or more. [Measurement conditions for adhesive strength over time (N / 25 mm)] The pressure-sensitive adhesive sheet was cut to 25 mm x 200 mm in an environment of 23°C and 50% RH, and the pressure-sensitive adhesive layer was then placed on a SUS-BA plate as an adherend, and a 2 kg roller was used to press and adhere it. After leaving the sheet to stand for 24 hours in the same atmosphere, the 180-degree peel strength (N / 25 mm) was measured at a peel speed of 300 mm / min using an autograph (Shimadzu Corporation, Autograph AGS-H 500N), and this was taken as the adhesive strength over time.

2. An adhesive sheet as described in claim 1, characterized in that the structural moiety derived from the polyol component (b) contains at least one of a structural moiety derived from a dihydric alcohol (b1) and a structural moiety derived from a trihydric or higher polyol (b2).

3. The adhesive sheet according to claim 1, characterized in that the structural portion derived from the polyol component (b) contains a structural portion derived from at least one selected from the group consisting of ethylene glycol, 2-methyl-1,3-propanediol, and neopentyl glycol.

4. The adhesive sheet according to claim 1, wherein the polyester resin (i') has an ester bond concentration of 9.0 to 12.5 mmol / g.

5. The adhesive sheet according to claim 1, wherein the glass transition temperature of the polyester resin (i') is -50 to -10°C.

6. An adhesive sheet described in any one of claims 1 to 5, characterized in that a polyester resin (i') having structural moieties derived from the polyvalent carboxylic acids (a) and structural moieties derived from the polyol component (b) is crosslinked by a crosslinking agent (ii).

7. The adhesive sheet described in claim 6, characterized in that the crosslinking agent (ii) is an isocyanate-based crosslinking agent (ii-1).

8. An adhesive sheet described in any one of claims 1 to 7, characterized in that a substrate is laminated on one side of the adhesive layer and a release-treated sheet is laminated on the other side.

9. An adhesive sheet as described in claim 8, characterized in that the substrate is a polyester resin sheet.

10. An adhesive sheet described in any one of claims 1 to 7, characterized in that release-treated sheets are laminated on both sides of the adhesive layer.

11. An adhesive sheet according to claim 8 or 9, characterized in that the adherend is a polyimide.

12. An adhesive sheet as described in claim 8 or 9, characterized in that it is used for fixing electronic components.