TWI834806B - Hardening compositions, hardened materials, products with hardened materials - Google Patents

Abstract

The present invention provides a curable composition capable of forming a flexible laminate excellent in bending durability and shape recovery. The curable composition of the present invention includes a (meth)acrylate polymer and a first monomer; the number average molecular weight of the aforementioned polymer is 40,000 to 750,000; and the aforementioned first monomer has a molecular weight of less than 35,000. It has more than one polyoxyalkylene chain and one (meth)acrylyl group in one molecule; and the content of the first monomer is 10 to 50 parts by mass relative to 100 parts by mass of the aforementioned polymer.

Description

Hardening compositions, hardened materials, products with hardened materials

The present invention relates to a curable composition, a cured product of the curable composition, and a product provided with the cured product.

In recent years, in addition to rigid display panels, a flexible display panel having bendability or flexibility has been developed. The flexible display panel includes, for example, a flexible laminate system in which a flexible display panel body such as an organic EL (Electronic Luminescent) display panel is laminated with an optical film or a protective film through an adhesive layer. sexual components. Patent Documents 1 and 2 describe a composition including a (meth)acrylate copolymer having a specific monomer composition and a cross-linking agent as an adhesive suitable for forming a flexible laminate.

Prior technical literature patent documents Patent Document 1: Japanese Patent Application Publication No. 2017-95654 Patent Document 2: International Publication No. 2018/173896

The problem to be solved by the invention As peripheral technologies develop, the required characteristics of flexible laminates constituting flexible display panels continue to escalate. For example, it is desired to have excellent bending durability, that is, it is not easy to cause defects such as whitening, peeling, embossing, and cracks due to bending, and it is desired to have excellent shape recovery properties, that is, it is not easy to deform even if it is bent or subjected to tensile stress. However, these characteristics are not sufficient for the flexible laminate formed using the adhesives described in Patent Documents 1 and 2. An object of the present invention is to provide a curable composition capable of forming a flexible laminate excellent in bending durability and shape recovery, a cured product of the curable composition, and a product provided with the cured product.

means to solve problems The present invention has the following aspects. [1] A curable composition including a (meth)acrylate polymer and a first monomer; The number average molecular weight of the aforementioned polymer is 40,000 to 750,000; The aforementioned first monomer has a molecular weight of less than 35,000 and has more than one polyoxyalkylene chain and one (meth)acrylyl group in one molecule; and The content of the first monomer is 10 to 50 parts by mass relative to 100 parts by mass of the aforementioned polymer. [2] The curable composition according to [1], wherein the molecular weight of the first monomer is a number average molecular weight. [3] The curable composition according to [1] or [2], wherein the glass transition temperature of the first monomer is -55°C or lower. [4] The curable composition according to any one of [1] to [3], wherein the molecular weight distribution of the first monomer is 1.03 to 1.2. [5] The curable composition according to any one of [1] to [4], wherein the first monomer contains 0.3 to 1.9 mass % of urethane bonds relative to the total amount of monomers. [6] The curable composition according to any one of [1] to [5], wherein the glass transition temperature of the polymer is -75 to -40°C as determined by differential scanning calorimeter analysis. [7] The curable composition according to any one of [1] to [6], further containing a cross-linking agent. [8] The curable composition according to any one of [1] to [7], which further contains a photopolymerization initiator. [9] The curable composition according to any one of [1] to [8], wherein the total content of the polymer and the first monomer is 80 mass % or more relative to the total amount of the curable composition. . [10] A cured product of the curable composition described in any one of [1] to [9]. [11] The hardened material described in [10] has a tan δ peak temperature of dynamic viscoelasticity, that is, a glass transition temperature of -35°C or less. [12] An adhesive sheet including an adhesive layer composed of the hardened material described in [10] or [11]. [13] The adhesive sheet as described in [12], wherein the thickness of the adhesive layer is 10 to 150 μm. [14] A laminated body having an adhesive layer composed of the hardened material according to [10] or [11], and a flexible member laminated through the adhesive layer. [15] The laminate according to [14], wherein the thickness of the adhesive layer is 10 to 150 μm. [16] The laminate according to [14] or [15], wherein the flexible member is at least one member selected from the group consisting of a surface protection panel, an optical film, a touch panel, and a display panel body. [17] A flexible display including the laminate described in any one of [14] to [16].

Invention effect According to the present invention, it is possible to obtain a curable composition capable of forming a flexible laminate excellent in bending durability and shape recovery, a cured product of the curable composition, and a product provided with the cured product.

In this specification, the compound represented by formula (1) is denoted as compound 1. Compounds represented by other formulas are also represented in the same manner. The terms used in this manual are defined as follows. "Unit" means a group of atoms formed directly by the polymerization of monomers. "(Meth)acrylate" means either or both acrylate and methacrylate. "Number of functional groups" means the number of (meth)acryloxy groups in one molecule unless otherwise specified. Unless otherwise specified, the "average number of functional groups" means the average number of (meth)acryloxy groups per molecule expressed by the formula weight obtained from the chemical formula or the number average molecular weight is 1 unit. The "index" is a value obtained by dividing the mole number of the isocyanate group of the isocyanate compound by the mole number of the hydroxyl group of the oxyalkylene polymer and multiplying it by 100 times. Also called "NCO/OH ratio". "Sheet" conceptually includes sheets, films, and strips. "Flexible" means a flexible or bendable property, including a property that can be folded to a bending radius of less than 3 mm and still return to its shape (Foldable), such as a property that can be bent or curled to a bending radius of more than 3 mm. The ability to recover its shape (Rollable: rollable), and the ability to remain undamaged when fixed in a bent state (Bendable: bendable).

The hydroxyl value of the polyol is obtained by measurement based on JIS K1557 (2007 edition). The hydroxyl-converted molecular weight is calculated by applying the hydroxyl value to the calculation formula "{56100/(hydroxyl value)}×(number of hydroxyl groups of the initiator)". The number average molecular weight and the mass average molecular weight are polystyrene-converted molecular weights measured by gel permeation chromatography (GPC) using a calibration curve made with a standard polystyrene sample of known molecular weight. Molecular weight distribution refers to the value obtained by dividing the mass average molecular weight (hereinafter referred to as Mw) by the number average molecular weight (hereinafter referred to as Mn) (Mw/Mn). When a peak of an unreacted low molecular weight component (monomer, etc.) appears in GPC measurement, the number average molecular weight and mass average molecular weight are calculated after excluding the peak. Even if Mn is specified, if there is no molecular weight distribution, the molecular weight expressed by the formula weight obtained from the chemical formula will be used instead.

In the present invention, the glass transition temperature of the hardened material is the tan δ peak temperature obtained in the dynamic viscoelasticity measurement. In the present invention, the glass transition temperature of the polymer is the glass transition temperature analyzed by a differential scanning calorimeter (DSC). In the present invention, the glass transition temperature of a monomer is the tan δ peak temperature obtained by measuring dynamic viscoelasticity after adding a photopolymerization initiator only to the target monomer and hardening it.

The curable composition of this embodiment includes a polymer (hereinafter also referred to as polymer A) and a first monomer (hereinafter also referred to as monomer B).

＜Polymer A＞ Polymer A is a homopolymer or copolymer having (meth)acrylate as the main unit and a number average molecular weight of 40,000 to 750,000. The polymer A in the curable composition may be one type or two or more types. Examples of monomers used to produce polymer A include: (meth)acrylic acid alkyl esters, carboxyl group-containing monomers, hydroxyl group-containing monomers, and Amine-containing monomers, epoxy-containing monomers, amide-containing monomers, vinyl monomers, and macromonomers. One type may be used alone, or two or more types may be combined.

Particularly preferred monomers include the following monomers a1, a2, and a3. Monomer a1: alkyl (meth)acrylate having an alkyl group having 4 to 18 carbon atoms bonded to a (meth)acryloxy group. Monomer a2: a monomer that has a carboxyl group and can be copolymerized with monomer a1. Monomer a3: a monomer that has organic functional groups and can be copolymerized with monomer a1.

The alkyl group having 4 to 18 carbon atoms bonded to the (meth)acryloxy group of monomer a1 is preferably a straight chain or a branched chain. Examples of monomer a1 include: (n-butylmeth)acrylate, isobutyl(meth)acrylate, second-butyl(meth)acrylate, third-butyl(meth)acrylate, (meth)acrylic acid Pentyl ester, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, (meth)acrylate 2-Ethylhexyl acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate. If monomer a1 in which a linear or branched alkyl group having 4 to 12 carbon atoms is bonded to the (meth)acryloxy group is used, the cured product of the curable composition of this embodiment will tend to become soft. Monomer a1 bonded with a linear or branched alkyl group having 4 to 12 carbon atoms is preferred, such as butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate or lauryl (meth)acrylate. Ester is better.

Examples of monomer a2 include: (meth)acrylic acid, 2-(meth)acryloxyethylhexahydrophthalic acid, 2-(meth)acryloxypropylhexahydrophthalic acid, 2-(Meth)acryloxyethylphthalic acid, 2-(meth)acryloxypropylphthalic acid, 2-(meth)acryloxyethylmaleic acid, 2-(meth)acryloxyethylmaleic acid (Meth)acryloxypropylmaleic acid, 2-(meth)acryloxyethylsuccinic acid, 2-(meth)acryloxypropylsuccinic acid, crotonic acid, fumaric acid, horse Leic acid, Iconic acid. If monomer a2 is used, under high temperature and high humidity conditions, the hardened product will not be easily cloudy (moisture and heat resistance), and the adhesion will be easily improved. In particular, (meth)acrylic acid is preferred.

The organic functional group of monomer a3 is preferably hydroxyl or amide group, with hydroxyl being preferred. Examples of the monomer a3 include: (meth)hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. Ester, 4-hydroxybutyl (meth)acrylate, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N- Hydroxymethyl(meth)acrylamide, N-hydroxymethylpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(methyl) Acrylamide, diacetone (meth)acrylamide, maleamide, maleimide. If monomer a3 is used, the moisture and heat resistance can be easily improved. In particular, hydroxyalkyl (meth)acrylate is preferred, and 4-hydroxybutyl (meth)acrylate is preferred.

For example, the following aspect is suitable: relative to the total units of polymer A, the units mainly composed of monomer a1 are 50 to 99.9 mass %, and the units mainly composed of monomer a2 are 0.1 to 5.0 mass %, and the The total is 50.1~100% by mass. Or it is preferable that the following aspect is used: relative to the total units of polymer A, the units mainly composed of monomer a1 are 50 to 99.0 mass %, and the units mainly composed of monomer a3 are 1.0 to 20.0 mass %, and these The total is 51.0~100% by mass.

The Mw of polymer A is preferably 300,000 to 1.5 million, preferably 400,000 to 1.4 million, more preferably 450,000 to 1.3 million, and especially 500,000 to 1.2 million. If it is above the lower limit of the above range, the creep recovery rate and curl residual rate will become better; if it is below the upper limit, good coating properties will be easily obtained due to low viscosity. The Mn of polymer A is 40,000 to 750,000, preferably 70,000 to 700,000, more preferably 100,000 to 500,000, and more preferably 140,000 to 300,000. If it is above the lower limit of the above range, the creep recovery rate and curl residual rate are likely to be improved; if it is below the upper limit, good coating properties are likely to be obtained due to low viscosity. When two or more types of polymer A are included in the curable composition, each Mn is preferably within the above range. The molecular weight distribution of polymer A is preferably 2.0~8.0, preferably 2.1~7.5, and more preferably 2.2~7.0. If it is above the lower limit of the above range, the adhesion is likely to be better; if it is below the upper limit, the creep recovery rate will be even better. When two or more types of polymer A are included in the curable composition, the molecular weight distributions of each should be within the above range.

The glass transition temperature of polymer A is preferably -75~-40℃, preferably -70~-45℃, and more preferably -68~-50℃. If it is within the above range, peeling will not easily occur during the bending test at low temperature. When two or more types of polymer A are included in the curable composition, each glass transition temperature is preferably within the above range.

＜Monomer B＞ The molecular weight of monomer B is 35,000 or less, and there is at least one polyoxyalkylene chain in one molecule for ring-opening addition polymerization of alkylene oxide, and there is one (meth)acryloxy in one molecule. base. The monomer B in the curable composition may be one type or two or more types. Monomer B contributes to reducing the shrinkage of the curable composition of this embodiment during curing and reduces the elastic modulus of the cured product. By using the cured product of the curable composition of this embodiment as the adhesive layer of the laminate, the bending durability and shape recovery properties of the laminate can be improved. In addition, monomer B has one (meth)acryloxy group, so it has good stability in the cured product and is less likely to overflow. From the viewpoint of hardening speed, monomer B preferably has an acryloxy group.

Monomer B is preferably an oligomer with polyoxyalkylene chains and urethane bonds. The number of urethane bonds per molecule of the oligomer having a urethane bond is preferably one or more. From the viewpoint of easily reducing shrinkage during hardening and easily lowering the elastic modulus after hardening, one is preferred. Relative to the total amount of monomer B, the content of urethane bonds is preferably 0.3~1.9% by mass, preferably 0.32~1.6% by mass, and more preferably 0.35~1.3% by mass. If it is within the above range, good adhesion can be easily obtained. Relative to the total amount of monomer B, the content of urethane bonds is based on the assumption that all isocyanate groups present in the isocyanate compound used in the production of monomer B have formed urethane bonds (molecular weight 59), and by It is calculated from the following calculation formula. Content of urethane bond (unit: mass %)={Mi×59/Wb}×100 Wb: total mass of monomer B Mi: The total number of moles of isocyanate groups present in the isocyanate compound used to make monomer B of mass Wb

In the production step of monomer B, by-products other than monomer B may be produced in the product (hereinafter also referred to as "product B"). In order to fully exert its function as monomer B, the content of monomer B in product B relative to the total amount of product B is preferably 80 mass% or more, preferably 85 to 100 mass%. When product B contains monomer B in the above content, the function of monomer B can be fully exerted, so product B can be regarded as monomer B.

When product B can be regarded as monomer B, the average number of functional groups of product B calculated from the Mn and the number of functional groups of product B can be regarded as the average number of functional groups of monomer B. At this time, the average number of functional groups of product B is preferably 0.8~1.3, and 0.9~1.2 is preferred. If the average number of functional groups of product B is within the above range, it is easy to fully exert the functions of monomer B. The average number of functional groups of product B can be adjusted by the amount of impurities contained in the raw materials for producing monomer B and the index mentioned below. In addition, in this specification, the average number of (meth)acryloxy groups can be calculated using the average functional group number and index of the raw materials mentioned later.

The molecular weight of monomer B is less than 35,000, preferably 3,000~30,000, preferably 4,000~28,000, and even more preferably 5,000~26,000. The molecular weight of monomer B can be Mn. In this case, Mn is less than 35,000, preferably 3,000~30,000, preferably 4,000~28,000, and more preferably 5,000~26,000. If the molecular weight of monomer B or Mn is within the above range, the viscosity of the curable composition will be easily adjusted; if it is above the lower limit, the cured product will become softer. When two or more types of monomer B are included in the curable composition, each Mn is preferably within the above range. The molecular weight distribution of monomer B is preferably 1.03~1.2, preferably 1.05~1.15. When two or more types of monomer B are included in the curable composition, the molecular weight distribution of each should be within the above range. The glass transition temperature of monomer B is preferably -55°C or lower, preferably -58°C or lower, and more preferably -60°C or lower. If it is below the upper limit of the above range, the bending durability at low temperatures will be even better. From the perspective of easily improving the creep recovery rate, the lower limit value is preferably -85°C or above, and preferably -80°C or above. For example, the glass transition temperature of monomer B is preferably -85°C to -55°C, preferably -85°C to -58°C, -80°C to -58°C is more preferred, and -80°C to -60°C is particularly preferred. When two or more types of monomer B are included in the curable composition, each glass transition temperature is preferably within the above range.

In the curable composition of this embodiment, the content of monomer B is 10 to 50 parts by mass, preferably 11 to 45 parts by mass, preferably 12 to 40 parts by mass, based on 100 parts by mass of polymer A. ~30 parts by mass is better. If it is more than the lower limit of the above range, the bending durability of the hardened material at low temperatures can be easily obtained and becomes softer easily; if it is less than the upper limit, the heat resistance will be even more excellent.

Specific examples of monomer B include monomer B-1, monomer B-2, and monomer B-3 shown below. These may be used individually by 1 type, and may be used in combination of 2 or more types.

In particular, monomer B preferably contains one or more types selected from the group consisting of monomer B-1 and monomer B-2. Relative to the total amount of monomer B, the total content of monomer B-1 and monomer B-2 is preferably 50 mass% or more, more preferably 80 mass% or more, and 100 mass% is particularly preferred. If the total content of monomer B-1 and monomer B-2 is more than the lower limit of the above range, the curing shrinkage rate will be easily reduced, and the cured product will easily become soft. (B-1) (B-2), which represents the mass ratio of monomer B-1 and monomer B-2, is preferably 1:0~1:1.

[Single B-1] Monomer B-1 is an equimolar reactant of polyoxyalkylene monoalcohol and a compound having an isocyanate group and a (meth)acryloxy group. Polyoxyalkylene monoalcohol is obtained by ring-opening addition polymerization of alkylene oxide to an initiator with an active hydrogen group and an active hydrogen number of 1, and has an initiator residue, a polyoxyalkylene chain and A compound whose active hydrogen number corresponds to the hydroxyl group of the initiator. The alkylene oxide is preferably one having 2 to 4 carbon atoms. Specific examples include propylene oxide, ethylene oxide, 1,2-butylene oxide, and 2,3-butylene oxide. Examples of the active hydrogen-containing group of the initiator include hydroxyl group, carboxyl group, and amine group having one hydrogen atom bonded to a nitrogen atom, and hydroxyl group and carboxyl group are preferred. As the hydroxyl group, an alcoholic hydroxyl group is preferred. Examples of initiators with one active hydrogen number include monovalent alcohols, monovalent phenols, monovalent carboxylic acids, and amine compounds having one hydrogen atom bonded to a nitrogen atom. The initiator is preferably an aliphatic monohydric alcohol and an aliphatic monocarboxylic acid. Furthermore, a polyoxyalkylene monoalcohol having a lower molecular weight than the target polyoxyalkylene monoalcohol can be used as an initiator. The carbon number of the aliphatic monohydric alcohol of the initiator is preferably 1 to 20, preferably 2 to 8. The carbon number of the aliphatic monocarboxylic acid in the initiator includes the carbon atoms of the carboxyl group, and is preferably 2 to 20, preferably 2 to 8. The oxyalkylene group in the polyoxyalkylene monoalcohol is preferably composed of only an oxypropylene group or a combination of an oxypropylene group and other groups, and the oxyalkylene group other than the oxypropylene group is preferably an oxyalkylene group. Ethylene. The content of the oxypropylene group in the polyoxyalkylene monoalcohol relative to the total oxyalkylene group is preferably 50 to 100 mass%, and preferably 80 to 100 mass%. When the polyoxyalkylene monoalcohol contains an oxyalkylene group, the content of the oxyalkylene group in the polyoxyalkylene monoalcohol relative to the total oxyalkylene groups is preferably 1 mass% or more and less than 50 mass%, 5 It is more preferable that it is more than 20 mass % and less than 20 mass %. In addition, when the initiator is a polyoxyalkylene monoalcohol with a lower molecular weight than the target polyoxyalkylene monoalcohol, the oxyalkylene group in the initiator can be regarded as the oxyalkylene group in the resulting polyoxyalkylene monoalcohol. alkyl.

Low hydroxyl value (that is, high molecular weight) polyoxyalkylene monoalcohol can use alkylene oxides with more than 3 carbon atoms (especially propylene oxide) to react with the initiator in the presence of composite metal cyanide complex catalysts. Manufactured by ring-opening addition polymerization. Polyoxyalkylene monoalcohols with a low hydroxyl value having an oxyethylene group or a high hydroxyl value (preferably 50 mgKOH/g or above) having an oxyethylene group can be used as the initiator in the composite metal cyanide. It is produced by subjecting alkylene oxides with 3 or more carbon atoms (especially propylene oxide) to ring-opening addition polymerization in the presence of a compound complex catalyst. High hydroxyl value polyoxyalkylene monoalcohols can be produced by ring-opening addition polymerization of alkylene oxides with 3 or more carbon atoms as an initiator in the presence of an alkali catalyst such as KOH. The polyoxyalkylene monoalcohol used to produce monomer B-1 may also be a mixture of two or more polyoxyalkylene monoalcohols. In this case, it is preferable that each polyoxyalkylene monoalcohol is a polyoxyalkylene monoalcohol included in the above category. When producing polyoxyalkylene monoalcohol, the initiator or alkylene oxide to be put into the reaction system is usually one that has a small amount of water after removing the water through degassing under reduced pressure. Generally, when producing polyoxyalkylene monoalcohol, the moisture content of the initiator is as small as possible, preferably 500 ppm by mass or less, and even more preferably 300 ppm by mass or less. If the water content is within this range, the amount of polyoxyalkylene glycol generated from water can be suppressed, thereby suppressing the amount of by-products ultimately derived from the polyoxyalkylene glycol, and the resulting product can be easily converted into The upper limit of the average number of hydroxyl groups of the polyoxyalkylene monoalcohol is adjusted to 1.3 or less. In addition, the moisture content in the polyoxyalkylene monoalcohol used as a raw material is preferably as small as possible. It is preferably 300 mass ppm or less, preferably 250 mass ppm or less, and 50 to 200 mass ppm relative to the polyoxyalkylene monoalcohol. Excellent. If the moisture content is within the above range, less by-products, which are reaction products between moisture and isocyanate group-containing compounds, will be produced, thereby improving the stability of the reaction product. Furthermore, it is easy to suppress changes in the appearance of the curable composition containing the reaction product over time, and the elastic modulus of the cured product is easily improved.

As a compound having an isocyanate group and a (meth)acryloxy group, a (meth)acrylate having one isocyanate group is preferred, and an isocyanate alkyl (meth)acrylate is preferred. The compound having an isocyanate group and a (meth)acryloxy group is preferably a (meth)acrylate having an isocyanate group bonded to an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and the isocyanate alkyl (methyl) Acrylics are particularly good. The carbon number of the alkyl group excluding the isocyanate group of the isocyanatoalkyl group is preferably 8 or less, more preferably 4 or less. Specific examples of the compound having an isocyanate group and a (meth)acryloxy group include 2-isocyanateethyl (meth)acrylate and isocyanatemethylmethacrylate. Examples of commercially available products include Karenz-AOI and Karenz-MOI (both are product names of Showa Denko Co., Ltd.). The ideal range of Mn of monomer B-1 is the same as that of monomer B mentioned above. Monomer B-1 is preferably compound 3 described below. Monomer B-1 is preferably a monomer obtained by reacting compound 3a to be described later and compound 3b to be described later.

In Compound 3a and Compound 3b, each of the groups present in one molecule that can carry out the urethanation reaction is one, so it is easy to control the number of urethane bonds in one molecule of monomer B-1 to one. . If the number of urethane bonds in one molecule of monomer B-1 is small, the viscosity will easily decrease. Therefore, from the viewpoint that the curable composition has low viscosity and is easy to obtain a cured product excellent in flexibility, it is preferable that the monomer B contains the monomer B-1.

[Chemical formula 1]

[Chemical formula 2]

In formulas 3, 3a, and 3b, R ¹¹ is a hydrogen atom or a methyl group, and a hydrogen atom is preferred. R ¹² is an alkylene group having 2 to 4 carbon atoms, and a plurality of R ¹² present in one molecule may be the same as or different from each other. When there are two or more kinds of R ¹² in one molecule, the chain of -OR ¹² - may be block or random. R ¹² is preferably ethylidene and/or propylene. R ¹³ represents an alkyl group having 1 to 20 carbon atoms, or R ¹³ and the oxygen atom bonded to R ¹³ together represent a carboxylic acid residue having 1 to 20 carbon atoms. The carboxylic acid residue is a monovalent group obtained by removing the hydrogen atom in one carboxyl group from a monocarboxylic acid with a carbon number of 1 to 20 including the carbon atom in the carboxyl group (-COOH). From the viewpoint of easy reaction, R ¹³ is preferably an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 2 to 8 carbon atoms. b is an integer from 1 to 8, and preferably an integer from 1 to 4. c is an integer from 20 to 600, preferably an integer from 35 to 500, and preferably an integer from 65 to 250.

Compound 3a is a polyoxyalkylene monoalcohol, which can be obtained by the following method: using an alcohol or a compound obtained by ring-opening addition polymerization of alkylene oxide to an alcohol as an initiator, a known method for ring-opening addition polymerization of alkylene oxide is used. method; or a known method of ring-opening addition polymerization of alkylene oxide to the carboxyl group of a monocarboxylic acid. The hydroxyl value of compound 3a is preferably 1.6~56.1mgKOH/g, preferably 3.7~14mgKOH/g. The molecular weight converted to hydroxyl group is preferably 1,000 to 35,000, preferably 4,000 to 15,000. If the molecular weight of compound 3a in terms of hydroxyl group is within the above range, it is easy to adjust the Mn of monomer B-1 to the range of 1,000 to 35,000. If the hydroxyl-equivalent molecular weight of compound 3a is within the above range, it will be easy to adjust the average number of functional groups of the produced monomer B-1 to 0.8 to 1.3. The smaller the molecular weight in terms of hydroxyl groups is, the easier it is to adjust the upper limit of the average number of functional groups to 1.3 or less.

In the production of compound 3a, there is no need to specifically remove moisture by degassing under reduced pressure, and the amount of moisture generally contained in the raw materials to be put into the reaction system can be allowed. For example, generally, the smaller the moisture content of the initiator, the better, preferably 500 ppm or less, and even more preferably 300 ppm or less. If the water content is within the above range, the production amount of glycol generated from water can be suppressed, so ultimately the production amount of by-products having (meth)acryloxy groups added to the glycol can be suppressed, making it easier to The upper limit of the average number of functional groups of the product including by-products and monomer B (hereinafter referred to as "product B-1") is adjusted to 1.3 or less.

Compound 3b can be commercially available, and examples include: Karenz-AOI (R ¹¹ =H, b = 1 in Formula 3b), Karenz-MOI (R ¹¹ =CH ₃ , b = 1 in Formula 3b) (both Showa Electrical company product name). The reaction between compound 3a and compound 3b is a urethane esterification reaction, and can be carried out using known techniques. When carrying out these reactions, the blending ratio of compound 3b to compound 3a is preferably 80 to 100 in terms of index, more preferably 90 to 100, and 100 is the most optimal. If the index is within the above range, it will be easy to adjust the average number of functional groups of product B-1 within the range of 0.8~1.3.

In order to fully exert its function as monomer B, the content of monomer B-1 in product B-1 is preferably 80 mass% or more, preferably 85 to 100 mass%. When product B-1 contains monomer B-1 in the above content, the function of monomer B can be fully exerted, so product B-1 can be regarded as monomer B-1.

When product B-1 can be regarded as monomer B-1, the average number of functional groups calculated from the Mn and the number of functional groups of product B-1 can be regarded as the average number of functional groups of monomer B-1. At this time, the average number of functional groups of product B-1 is preferably 0.8 to 1.3, and preferably 0.9 to 1.2. If it is within the above range, Product B-1 will easily reduce the shrinkage during curing and the elastic modulus of the cured product.

Monomer B-1 is preferably compound 3 and includes monomer B-1-PO. Monomer B-1-PO exists in 1 molecule and has a propylene group content of 50 to 100 relative to the total amount of R ¹² Mol%.

In the monomer B-1-PO, relative to the total amount of R ¹² , the propylene group content is preferably 80 to 100 mol%, especially 100 mol%. When there is an alkylene group other than propylene group in R ¹² present in one molecule, the alkylene group other than propylene group is preferably an ethylene group. When R ¹² of monomer B-1-PO contains an ethylidene group as an alkylene group, the ethylene group content relative to the total amount of R ¹² is preferably 1 mol% or more and less than 30 mol%. 1 mole More than 1 mol % and less than 25 mol % is preferred.

And when using monomer B-1-PO, the content of monomer B-1-PO relative to monomer B is preferably 50 to 100 mass%, and preferably 80 to 100 mass%. If the content of monomer B-1-PO is above the lower limit of the above range, the curable composition will have low viscosity and the cured product will have good flexibility.

[Single B-2] Monomer B-2 is an equimolar reaction product of polyoxyalkylene monoalcohol, diisocyanate and compounds having groups reactive with isocyanate groups and (meth)acryloxy groups. The polyoxyalkylene monoalcohol in monomer B-2 is the same as the aforementioned polyoxyalkylene monoalcohol. Among the compounds having a group reactive with an isocyanate group and a (meth)acryloxy group, the group reactive with the isocyanate group includes, for example, a hydroxyl group and an amine group having a nitrogen atom bonded to a hydrogen atom. The number of hydroxyl groups in the group that can react with the isocyanate group or the number of hydrogen atoms bonded to the nitrogen atom is preferably one. The group that can react with the isocyanate group is preferably a hydroxyl group bonded to an aliphatic hydrocarbon group or an alicyclic hydrocarbon group. The compound having a group that can react with an isocyanate group and a (meth)acryloxy group is preferably hydroxyalkyl (meth)acrylate and hydroxycycloalkyl (meth)acrylate, and the number of carbon atoms in the hydroxyalkyl group Hydroxyalkyl (meth)acrylate with a value of 8 or less is particularly preferred. Specific examples of the compound having a group reactive with an isocyanate group and a (meth)acryloxy group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and (meth)acrylate. ) 2-hydroxybutyl acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate. Commercially available products include: Lightester HO-250(N), Lightester HOP(N), Lightester HOA(N), Lightester HOP-A(N), Lightester HOB(N) (all product names of Gyoei Chemical Co., Ltd.), 4-HBA (Osaka Organic Chemical Industry Co., Ltd. product name). The ideal range of Mn of monomer B-2 is the same as that of monomer B mentioned above. Monomer B-2 is preferably compound 4 described below. The monomer B-2 is preferably a compound obtained by reacting the later-described compound 4a with the later-described compound 4b to obtain a prepolymer having an isocyanate group at the end (isocyanate group-terminated urethane prepolymer). A compound obtained by reacting the isocyanate groups of prepolymers.

[Chemical formula 3]

[Chemical formula 4]

In formulas 4, 4a, 4b, and 4c, R ²¹ is a hydrogen atom or a methyl group, and a hydrogen atom is preferred. R ²² is an alkylene group having 2 to 4 carbon atoms, and a plurality of R ²² present in one molecule may be the same as or different from each other. When there are two or more kinds of R ²² in one molecule, the chain of -OR ²² - may be block or random. R ²² is preferably ethylidene and/or propylene. R ²³ represents an alkyl group having 1 to 20 carbon atoms, or R ²³ and the oxygen atom bonded to R ²³ together represent a carboxylic acid residue having 1 to 20 carbon atoms. The carboxylic acid residue is a monovalent group obtained by removing a hydrogen atom in one carboxyl group from a monocarboxylic acid with a carbon number of 1 to 20 including the carbon atom in the carboxyl group. From the viewpoint of easy reaction, R ²³ is preferably an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 2 to 8 carbon atoms.

R ²⁴ is a divalent group in which the isocyanate group has been removed from compound 4b. Examples of compound 4b include compounds having two isocyanate groups, preferably isophorone diisocyanate or hexamethylene diisocyanate. d is an integer from 1 to 8, and an integer from 1 to 4 is suitable. e is an integer from 20 to 600, preferably an integer from 35 to 500, and an integer from 65 to 250.

Compound 4a is a polyoxyalkylene monoalcohol, which can be obtained by the following method: using an alcohol or a compound obtained by ring-opening addition polymerization of alkylene oxide to an alcohol as an initiator, a known method of ring-opening addition polymerization of alkylene oxide is used. method; or a known method of ring-opening addition polymerization of alkylene oxide to the carboxyl group of a monocarboxylic acid. The hydroxyl value of compound 4a is preferably 1.6~56.1mgKOH/g, preferably 3.7~14mgKOH/g. The molecular weight converted to hydroxyl group is preferably 1,000 to 35,000, preferably 4,000 to 15,000. If the molecular weight in terms of hydroxyl group of compound 4a is within the above range, the Mn of monomer B-2 can be adjusted within the range of 1,000 to 35,000.

The water content and molecular weight when producing compound 4a are the same as those of compound 3a. Even when Compound 4a is produced, as in the case of Compound 3a, there is a by-product in which a (meth)acryloxy group is added to a diol generated from water contained in the raw material. The situation of the product of monomer B-2 (hereinafter also referred to as "product B-2").

The reaction in which Compound 4a and Compound 4b are reacted to obtain a prepolymer having an isocyanate group at the end (isocyanate group-terminated urethane prepolymer) is a urethanation reaction and can be performed using a known technique. When carrying out these reactions, the blending ratio of compound 4b to compound 4a is preferably 100 to 200 in terms of index, preferably 180 to 200, and 200 is the most optimal. If the index is within the above range, it will be easy to adjust the average functional group number of product B-2 within the range of 0.8~1.3.

The reaction between the obtained isocyanate group-terminated urethane prepolymer and compound 4c is a urethanation reaction, and can be carried out using known techniques.

When making these reactions, the blending ratio of the prepolymer and the compound 4c is preferably 1:1.0~1.1, with the molar ratio of the isocyanate group in the prepolymer:the hydroxyl group in the compound 4c being 1:1.0~1.05. Better. If it is within the above range, it is easy to adjust the average number of functional groups of product B-2 to the range of 0.8~1.3. In order to fully exert its function as monomer B, the content of monomer B-2 in product B-2 is preferably 80 mass% or more, preferably 85 to 100 mass%. When product B-2 contains monomer B-2 in the above content, the function of monomer B can be fully exerted, so product B-2 can be regarded as monomer B-2.

When product B-2 can be regarded as monomer B-2, the average number of functional groups calculated from the Mn and the number of functional groups of product B-2 can be regarded as the average number of functional groups of monomer B-2. At this time, the average number of functional groups of product B-2 is preferably 0.8 to 1.3, and preferably 0.9 to 1.2. If it is within the above range, Product B-2 will easily reduce the shrinkage during hardening and reduce the elastic modulus of the hardened product.

Monomer B-2 is preferably compound 4 and includes monomer B-2-PO. The monomer B-2-PO exists in 1 molecule, and the propylene group content is 50 to 100 relative to the total amount of R ²² Mol%.

In the monomer B-2-PO, relative to the total amount of R ²² , the propylene group content is preferably 80 to 100 mol%, especially 100 mol%. When there is an alkylene group other than propylene group in R ²² present in one molecule, the alkylene group other than propylene group is preferably an ethylene group. When R ²² of monomer B-2-PO contains an ethylene group as an alkylene group, the ethylene group content is preferably 1 mol% or more and less than 30 mol% relative to the total amount of R ^22. 1 mole More than 1 mol % and less than 25 mol % is preferred.

And when using monomer B-2-PO, the content of monomer B-2-PO relative to monomer B is preferably 50 to 100 mass%, and preferably 80 to 100 mass%. If the content of monomer B-2-PO is above the lower limit of the above range, the curable composition will have low viscosity and the cured product will have good flexibility.

[Monomer B-3] Monomer B-3 is an oligomer with a functional group of 1 obtained by reacting the later-described compound 5a with the aforementioned compound 3b. The ideal range of Mn of monomer B-3 is the same as that of monomer B mentioned above.

[Chemical formula 5]

In Formula 5a, R ³² is an alkylene group having 2 to 4 carbon atoms, and a plurality of R ³² present in one molecule may be the same as or different from each other. When there are two or more kinds of R ³² in one molecule, the chain of -OR ³² - may be block or random. R ³² is preferably ethylidene and/or propylene. Relative to the total amount of R ³² , the propylene group content is preferably 50 to 100 mol%, preferably 80 to 100 mol%. When there is an alkylene group other than propylene group in R ³² present in one molecule, the alkylene group other than propylene group is preferably an ethylene group.

f in Formula 5a is an integer between 20 and 600, and an integer between 35 and 500 is preferred, and an integer between 65 and 250 is preferred. If f is within the above range, it will be easy to adjust the Mn of monomer B-3 to the range of 1,000~35,000.

The reaction between compound 5a and compound 3b is a urethane esterification reaction, and can be carried out using known techniques. In this reaction, the hydroxyl groups at both ends of compound 5a can react with compound 3b, so in addition to the oligomer with a functional group of 1, a product containing an oligomer with a functional group of 2 is sometimes obtained as a by-product ( Hereinafter also referred to as "Product B-3)). The average number of functional groups of product B-3 is preferably 0.8~1.3, and preferably 0.9~1.2.

In this reaction, the blending ratio of compound 3b to compound 5a is preferably 30 to 50 in terms of index, preferably 40 to 50, and 50 is the most optimal. If the index is within the above range, it is easy to obtain a compound in which one molecule of compound 3b reacts with one molecule of compound 5a, and it is easy to adjust the average number of functional groups of product B-3 within the range of 0.8 to 1.3.

In order to fully exert its function as monomer B, the content of monomer B-3 in product B-3 is preferably 80 mass% or more, preferably 85 to 100 mass%. When product B-3 contains monomer B-3 in the above content, the function of monomer B can be fully exerted, so product B-3 can be regarded as monomer B-3.

When product B-3 can be regarded as monomer B-3, the average number of functional groups calculated from the Mn and the number of functional groups of product B-3 can be regarded as the average number of functional groups of monomer B-3. At this time, the average number of functional groups of product B-3 is preferably 0.8 to 1.3, and preferably 0.9 to 1.2. If it is within the above range, product B-3 will easily reduce the shrinkage during curing and the elastic modulus of the cured product.

<Crosslinking agent> The curable composition of this embodiment preferably contains a crosslinking agent. The cross-linking agent is a compound having two or more cross-linking functional groups that can be polymerized with monomer B. If a cross-linking agent is blended, the heat resistance and creep recovery rate can be easily improved. The cross-linking functional group is preferably selected from (meth)acrylyl group, epoxy group, isocyanate group, carboxyl group, hydroxyl group, carbodiimide group, Zozolinyl, acridine At least one of group, vinyl group, amine group, imine group and amide group. The number of cross-linking functional groups in 1 molecule is preferably 2 to 4, with 2 or 3 being preferred, and 2 being more preferred. The cross-linking functional group can also be protected by a deprotectable protecting group.

The cross-linking agent is preferably a polyfunctional (meth)acrylate. Examples include polyfunctional (meth)acrylates described in International Publication No. 2018/173896 [0136]. From the perspective of easily improving the creep recovery rate, the following are suitable: 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol. Alcohol di(meth)acrylate, trimethylolpropane triacrylate, neopentylerythritol triacrylate, ethoxylated isocyanurate triacrylate. One type of cross-linking agent may be used, or two or more types may be used in combination.

The usage amount of the cross-linking agent is preferably 1 to 20 mol relative to 1 mol of the monomer B. The cross-linking functional group of the cross-linking agent is preferably 1 to 20 mol, preferably 2 to 15 mol, and 2.5 to 13 mol. Ears are better. If it is above the lower limit of the above range, the heat resistance of the cured product will be more excellent; if it is below the upper limit, the creep recovery rate will be easily increased.

＜Photopolymerization initiator＞ The curable composition of this embodiment may be photocurable or thermosetting. From the viewpoint of being able to harden at low temperatures and having a fast hardening speed, photocurable ones are preferred. When the curable composition is photocurable, it is preferable to contain a photopolymerization initiator. If the curable composition is photocurable, for example, when it is used to manufacture a display device, high temperatures are not required, so there is less concern that the display device will be damaged due to high temperatures.

The photopolymerization initiator functions as a reaction initiation aid in the cross-linking reaction of the cross-linking agent. From the viewpoint of easily controlling the cross-linking reaction, a photopolymerization initiator that reacts to ultraviolet rays with a wavelength of 380 nm or less is preferred. Examples of the photopolymerization initiator include those described in International Publication No. 2018/173896, [0147] to [0151]. The photopolymerization initiator is preferably a hydrogen-abstraction type photopolymerization initiator, which is an initiator that is excited by light and forms an excited complex with a hydrogen donor in the system to transfer hydrogen from the hydrogen donor. Specific examples of the hydrogen abstraction type photopolymerization initiator include benzophenone, 4-methyl-diphenylketone, 2,4,6-trimethyldiphenylketone, and 4-phenyldiphenylketone. , 3,3'-dimethyl-4-methoxydiphenylketone, 4-(meth)acryloxydiphenylketone, 4-[2-((meth)acryloxy) Ethoxy] diphenyl ketone, 4-(meth)acryloyloxy-4'-methoxydiphenyl ketone, 2-benzoyl benzoic acid methyl ester, benzoyl benzoic acid methyl ester. The number of photopolymerization initiators may be one type, or two or more types may be used in combination.

Relative to 100 parts by mass of polymer A, the usage amount of the photopolymerization initiator is preferably 0.1 to 10 parts by mass, and preferably 0.3 to 5 parts by mass. When the usage amount of the photopolymerization initiator is within the above range, it is easy to obtain appropriate reaction sensitivity to active energy rays.

＜Other ingredients＞ The curable composition of this embodiment may contain known components as needed, in addition to the polymer A, the monomer B, the crosslinking agent, and the photopolymerization initiator. Examples of other ingredients include: silane coupling agent, adhesion-promoting resin, antioxidant, light stabilizer, metal deactivator, anti-rust agent, anti-aging agent, hygroscopic agent, anti-hydrolysis agent, anti-static agent, defoaming agent , inorganic particles, etc. Reaction catalysts (tertiary amine compounds, quaternary ammonium compounds or tin laurate compounds, etc.) may also be included as required. Solvents may also be included if required. Multifunctional isocyanate compounds may also be included upon request. Specific examples of the polyfunctional isocyanate compound include the components described in Japanese Patent No. 6375467 [0062].

＜Cureable composition＞ The curable composition of this embodiment contains polymer A, monomer B, a crosslinking agent if necessary, a photopolymerization initiator, and other components. By hardening the mixture, the target hardened product can be obtained. The mixing order of the ingredients is not limited. The heat treatment can also be performed after mixing the ingredients. The components constituting the curable composition may be mixed in advance or may be mixed just before curing. For example, the photopolymerization initiator may be added to a premix in which components other than the photopolymerization initiator are mixed in advance, just before curing. The curable composition of this embodiment can be used even if it does not contain a solvent. Solvents may also be included upon request. Solvents should be removed during or after hardening.

The total content of polymer A and monomer B is preferably 80 mass% or more relative to the total amount of the curable composition, preferably 85 mass% or more, and more preferably 90 mass% or more.

<Cured material> The cured material of this embodiment can be obtained by hardening the curable composition of this embodiment. For example, the curable composition is molded into a desired shape and irradiated with ultraviolet rays to cure it. Examples of methods for molding the curable composition include coating on a base material, extrusion molding, and injection into a mold. The amount of ultraviolet irradiation should be 0.1~5J/cm ² , 0.3~4J/cm ² is better, and 0.5~3J/cm ² is better. If it is above the lower limit of the above range, the heat resistance and creep recovery rate will become better; if it is below the upper limit, coloring will be less likely.

The upper limit of the tan δ peak temperature of the dynamic viscoelasticity of the hardened material of this embodiment, that is, the glass transition temperature, is preferably -35°C, preferably -37°C, and more preferably -38°C. If it is below the above upper limit, the bending durability at low temperatures will be even better. From the viewpoint of easily improving the curl residual rate, the lower limit of the glass transition temperature is preferably -80°C, preferably -70°C, and more preferably -60°C. The tan δ peak temperature of the dynamic viscoelasticity of the hardened material of this embodiment, that is, the glass transition temperature, is preferably -80°C to -35°C, preferably -70°C to -37°C, and more preferably -60°C to -38°C. If the glass transition temperature of the hardened material is within the above range, the bending durability at low temperatures will be even better. The storage elastic modulus of the hardened material of this embodiment at -20°C is preferably 150 to 1500, preferably 200 to 1000, and more preferably 250 to 600. If it is within the above range, the cured product of the present invention can easily maintain flexibility at low temperatures, and when used as an adhesive sheet for a laminated body, the bending durability and shape recovery properties of the laminated body can be further improved. The storage elastic modulus of the hardened material of this embodiment at 25°C is preferably 80 to 700, preferably 100 to 500, and more preferably 100 to 250. If it is within the above range, the cured product of the present invention can easily maintain flexibility even near room temperature, and when used as an adhesive sheet for a laminated body, the bending durability and shape recovery properties of the laminated body can be further improved. The storage elastic modulus of the hardened material of this embodiment at 80°C is preferably 20 to 300, preferably 30 to 250, and more preferably 45 to 200. If it is within the above range, the cured product of the present invention can easily maintain flexibility even at high temperatures. When used as an adhesive sheet for a laminated body, the bending durability and shape recovery properties of the laminated body can be further improved. "E'(-20℃)/E'(80℃)" of the hardened material of this embodiment is preferably 1.0~9.0, more preferably 1.0~8.0, more preferably 1.0~7.0, and the "E'(-20℃) /E'(80℃)" represents the ratio of the storage elastic modulus E'(-20℃) (kPa) at -20℃ to the storage elastic modulus E'(80℃) (kPa) at 80℃. If it is within the above range, the elastic modulus of the cured product of the present invention will change less due to temperature, and the flexibility can be easily maintained. When used as an adhesive sheet for a laminated body, the bending durability of the laminated body can be further improved. and shape recovery.

＜Adhesive sheet＞ The hardened material of this embodiment can be used as an adhesive layer. The adhesive sheet of this embodiment has a sheet-shaped adhesive layer composed of the cured product of this embodiment. The release film should be placed in contact with both sides of the adhesive layer. As the release film, a known release film can be used. The adhesive sheet can be produced, for example, by applying a curable composition to the first release film and then curing it, and then laminating the second release film thereon; or by coating the first release film with a curable composition. A method in which a curable composition is clothed, a second release film is laminated thereon, and then cured.

In the adhesive sheet of this embodiment, the thickness of the adhesive layer is preferably 10 to 150 μm, preferably 20 to 120 μm, and more preferably 25 to 100 μm. If it is above the lower limit of the above range, the adhesive layer will become smoother easily; if it is below the upper limit, the repeated bending durability will be better.

＜Laminated body＞ The laminated body of this embodiment includes an adhesive layer composed of the hardened material of this embodiment and a flexible member laminated through the adhesive layer. The flexible member may be a member constituting a flexible display panel. Examples of flexible components include surface protection panels, optical films, touch panels, and display panel bodies. Examples of surface protection panels include thin plate-like cover glass and cover films. Optical films are components with optical functions. Examples of optical films include polarizing films, phase difference films, optical filters, anti-reflection films, near-infrared cutoff films, and electromagnetic wave shielding films. A touch panel has a touch sensor mounted on a thin plate glass base material or a plastic base material, for example. The display panel body may be an organic EL display panel.

The laminated body of this embodiment is flexible and should have a shape that will not break even if it is fixed into a curved shape in a resting state (Bendable), and can be bent or curled to a bending radius of 3 mm or more. One or more of the properties of returning to shape (Rollable: rollable), or the property of returning to shape when folded to a bending radius less than 3mm (Foldable: foldable).

In the laminate of this embodiment, the thickness of the adhesive layer is preferably 10 to 150 μm, preferably 20 to 120 μm, and more preferably 25 to 100 μm. If it is above the lower limit of the above range, the adhesive layer will become smoother easily; if it is below the upper limit, the repeated bending durability will be better.

＜Flexible display＞ The flexible display of this embodiment includes the laminated body of this embodiment. By containing the polymer A and the monomer B, the curable composition of this embodiment can lower the glass transition temperature of the cured product and lower the elastic modulus as shown in the examples described below. Therefore, for example, even when used as an adhesive layer between components constituting a flexible display, it can still have both bending durability and shape recovery properties. The flexible display is preferably a foldable display with a structure of a foldable display screen. Example

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited by these examples.

＜Measurement method and evaluation method＞ [Measurement of molecular weight] The mass average molecular weight (Mw) and the number average molecular weight (Mn) can be measured by gel permeation chromatography (GPC) under the following conditions, and the molecular weight distribution (Mw/Mn) can be calculated from the measured values of Mw and Mn. ・Analysis device: HLC-8120GPC Tosoh Corporation product name ・Column: G7000HXL (Tosoh Corporation's product name), GMHXL (Tosoh Corporation's product name), and GMHXL (Tosoh Corporation's product name) are connected in sequence. ・Pipe string size: 7.8mmφ×30cm each, 90cm in total ・Pipe string temperature: 40℃ ・Flow rate: 0.8mL/min ・Injection volume: 100μL ・Eluate: Tetrahydrofuran ・Detector: Differential Refractometer (RI) ・Standard sample: polystyrene

[Measurement of glass transition temperature of polymer A] For the polymer A obtained in each example, a differential scanning calorimeter (EXSTAR 6000 DSC 6200, product name of Seiko Instruments Inc.) was used. The sample amount was about 10 mg, the temperature rising rate was 10°C/min, and the temperature range was between -80 and 25°C. Measure the glass transition temperature under these conditions.

[Measurement of the storage elastic modulus and glass transition temperature of the hardened material] Pour the curable composition prepared in each example into a polysiloxane mold with a width of 5 mm × a length of 15 mm × a thickness of 2 mm, and use a conveyor belt type UV in a nitrogen environment Irradiation machine (manufactured by ORC Co., Ltd.) was used to harden the film under the conditions of HgXe lamp, illumination intensity of 100 mW/cm ² and accumulated light amount of 1 J/cm ² . The obtained hardened product was used as a test sample. For the test sample, a dynamic viscoelasticity measuring device (EXSTAR 6000 DMS 6100, product name of Seiko Instruments Inc.) was used in the tensile mode and in the temperature range of -80°C to 130°C at a heating rate of 3°C/min. The storage elastic modulus E' (kPa) is measured under the conditions of frequency 1Hz and strain 1%. Furthermore, the temperature at which the measured tan δ shows a maximum value (tan δ peak temperature) was used as the glass transition temperature. The measurement results are listed in the table: storage elastic modulus E', Tg, and storage elastic modulus ratio (E'(-20℃)/E'(80℃)) at -20℃, 25℃ and 80℃ , the storage elastic modulus ratio (E'(-20°C)/E'(80°C)) represents the ratio of E' at -20°C to E' at 80°C.

[Evaluation method of bending durability and shape recovery of laminates] Use the following films. ・Polysilicone-treated PET: 75 μm-thick polyethylene terephthalate film (SP-PET-01-75BU, product name of Mitsui Chemicals Tohcello.Inc.) that has been subjected to silicone treatment (peeling treatment). ・Kapton film: 200EN, product name of DU PONT-TORAY CO., LTD., thickness 50μm. ・Corona-treated PET: Polyethylene terephthalate film (Lumirror S10, product name of TORAY Industries, Inc.) with a thickness of 50 μm has been subjected to corona treatment.

(Repeated bending test) Using an automatic coater equipped with a scraper (PI1210 automatic coater, product name of TESTER SANGYO CO,. LTD.), the curable compositions of each example were applied so that the thickness of the adhesive layer after curing became 25 μm. method, coated on the silicone-treated surface of silicone-treated PET. Next, a conveyor belt type UV irradiation machine (manufactured by ORC Corporation) was used in a nitrogen environment to harden under the conditions of HgXe lamp, illumination intensity of 100 mW/cm ² and accumulated light amount of 1 J/cm ² to form an adhesive layer. Attach the adhesive side to the Kapton film. Next, after peeling off the silicone-treated PET, the corona-treated surface of the corona-treated PET was bonded to the exposed adhesive layer to produce a laminate for testing. The laminated body for the test was 50 mm wide, 100 mm long, and 0.125 mm thick. Using a U-shaped planar bending tester (DLDM111LH, product name of Yuasa System Co., Ltd.), the obtained test laminate was bent approximately halfway in the length direction, and this operation was repeated. Specifically, the bending radius is 1.5mm and the Kapton film side is on the inside, and the bending force is released. This operation (released to 180°) is one operation. Repeatedly performs 100,000 operations at a speed of 60 times per minute. The appearance of the test laminate after the test was visually observed and evaluated based on the following criteria. A: There is no whitening, peeling, embossing or cracking, and there is no change in appearance. B: Although one or more of whitening, peeling, embossing or cracking occurs, the degree is slight and there is no practical problem. C: One or more of whitening, peeling, embossing or cracking is obviously produced, which is a practical problem.

(static bending test) The test laminate prepared in the same manner as the repeated bending test was used as a static bending test specimen. The laminated body for the test was 50 mm wide, 100 mm long, and 0.125 mm thick. Along the outer shape of a 3 mm thick plate whose end surface is processed into a curved surface (bending radius 1.5 mm), the static bending test specimen is closely adhered with the Kapton film side on the inside and fixed with tape. After leaving it to stand for 20 days at -20°C or room temperature (25°C), the appearance of the test laminate after the test was visually observed and evaluated based on the same criteria as the repeated bending test.

(Crim test, curl residual rate) The test laminate prepared in the same manner as the repeated bending test was cut into a width of 10 mm and a length of 50 mm to prepare a sample for the curl test. Along the shape of a 4 mm thick plate with an end surface processed into a curved surface (bending radius 2 mm), bend the center of the length direction of the curl test specimen and fix it with tape, then leave it at room temperature for 1 day. Next, remove the curl test sample from the plate, place it on a horizontal surface with the bent surface facing upward and forming an inverted U shape, and measure the height h (mm) from the horizontal surface to the bent surface. Calculate the curl remaining rate (unit: %) by the following formula. The lower the curl residual rate, the better the shape recovery. In addition, those that peeled off during the test are marked as F. Curl residual rate (%)={h/25}×100

(Creep recovery rate) Follow the same procedure as the repeated bending test to prepare the specimen for the creep test shown in Figure 1A. The symbol 1 in the figure is Kapton film, 2 is the adhesive layer, and 3 is corona-treated PET. In the shearing direction (X direction), the lengths of the Kapton film 1 and the corona-treated PET 3 are each set to 60 mm, and are the lengths from the end 1 a of the Kapton film 1 to the end 3 a of the corona-treated PET 3 (hereinafter referred to as The initial value of the total length in the X direction is set to 110mm. The thickness of the adhesive layer 2 was set to 25 μm. In the directions perpendicular to both the X direction and the thickness direction, the widths of the Kapton film 1 and the corona-treated PET 3 are respectively set to 10 mm. Fix the end 1a of the Kapton film 1 and the end 3a of the corona-treated PET 3 to a tensile testing machine respectively, and extend them in the X direction until the total length in the X direction is 300 μm longer than the initial value. For 1 time, repeat the operation 10 times and then let it sit for 1 minute. Figure 1B is an example of a creep test specimen after standing. The amount of residual strain after standing was observed with an optical microscope (Microscope VHX-1000, product name of KEYENCE), and the deflection amplitude from the initial position was measured (symbol 4 in Figure 1B). Calculate the creep recovery rate (unit: %) by the following formula. The higher the creep recovery rate, the better the shape recovery. Creep recovery rate (%) = {(300μm-deviation amplitude from the initial position (μm))/300μm}×100

[Manufacturing Example 1-1] Add 0.2g of zinc hexacyanocobaltate-tert-butyl alcohol complex (hereinafter referred to as "DMC-TBA") and 30g of n-butanol into a pressure-resistant reactor equipped with a mixer and a nitrogen inlet pipe, and set it to 130 3970g of propylene oxide (hereinafter referred to as PO) was added at a constant speed for 7 hours in a nitrogen atmosphere at ℃. Next, after confirming that the internal pressure of the pressure-resistant reactor stopped falling, the product was taken out to obtain 4000 g of polyoxyalkylene monoalcohol (monol 1) with a hydroxyl value of 5.6 mgKOH/g (hydroxyl-converted molecular weight: 10,000).

[Manufacturing Example 1-2] In the same manner as in Production Example 1-1, except that n-butanol was 59 g and PO was 3941 g, a polyoxyalkylene monoalcohol (monol 2) with a hydroxyl value of 11.5 mgKOH/g (hydroxyl-converted molecular weight: 4,880) was obtained. 4000g.

[Manufacturing Example 1-3] In the same manner as in Production Example 1-1, except that n-butanol was 21 g and PO was 3979 g, a polyoxyalkylene monoalcohol (monol 3) with a hydroxyl value of 4.1 mgKOH/g (hydroxyl-converted molecular weight: 13,680) was obtained. 4000g.

[Manufacturing Example 1-4] Add 0.5g of DMC-TBA and 74g of n-butanol into a pressure reactor equipped with a mixer and a nitrogen inlet pipe. In a nitrogen environment set to 130°C, add 7941g of PO and ethylene oxide at a constant speed for 15 hours. (hereinafter referred to as EO) 1985g of mixed solution. Next, after confirming that the internal pressure of the pressure-resistant reactor stopped falling, the product was taken out to obtain 10,000 g of polyoxyalkylene monoalcohol (monol 4) with a hydroxyl value of 5.2 mgKOH/g (hydroxyl-converted molecular weight: 10,790). In monoalcohol 4, the content of PO relative to the total of PO and EO is approximately 75 mol%.

[Manufacturing Example 1-5] Except that DMC-TBA was 0.25g, PO was 3743g, and EO was 1182g, a polyoxyalkylene monoalcohol with a hydroxyl value of 11.8 mgKOH/g (hydroxyl-converted molecular weight: 4,750) was obtained in the same manner as in Production Example 1-4. Unit alcohol 5) 5000g. In monoalcohol 5, the content of PO relative to the total of PO and EO is approximately 71 mol%.

[Manufacturing Example 2-1] Into a reaction vessel equipped with a stirrer and a nitrogen inlet pipe, 964.9 g of monoalcohol 1 (average hydroxyl number: 1.08) and 2-acrylyloxyethyl isocyanate (Karenz-AOI, product name of Showa Denko Co., Ltd., hereinafter referred to as AOI ) 13.1g, in the presence of 0.08g of 25% toluene solution of bismuth 2-ethylhexanoate, stir at 70°C for 3 hours to obtain a product containing monomer B1. The ratio (index) of the NCO group of the AOI to the OH group of the unit alcohol 1 is 100. The monomer B1 content in the product is 84% by mass. The Mn, Mw/Mn, average number of functional groups, urethane bond content, and glass transition temperature (Tg) of the obtained monomer B1 are listed in the table (the same below).

[Manufacturing Example 2-2] In Production Example 2-1, a product containing monomer B2 was obtained in the same manner except that 928.1 g of monoalcohol 2 (average hydroxyl number: 1.04) was used instead of monoalcohol 1 and the AOI was set to 26.8g. The monomer B2 content in the product is 92 mass%.

[Manufacturing Example 2-3] In Production Example 2-1, a product containing monomer B3 was obtained in the same manner except that 928.1 g of monoalcohol 3 (average hydroxyl number: 1.11) was used instead of monoalcohol 1 and the AOI was set to 8.6g. The monomer B3 content in the product is 80% by mass.

[Manufacturing Example 2-4] In Production Example 2-1, a product containing monomer B4 was obtained in the same manner except that 500.2 g of monoalcohol 4 (average hydroxyl number: 1.11) was used instead of monoalcohol 1 and the AOI was set to 6.6g. The monomer B4 content in the product is 96 mass%.

[Manufacturing Example 2-5] In Production Example 2-1, a product containing monomer B5 was obtained in the same manner except that 501.0 g of monoalcohol 5 (average hydroxyl number: 1.11) was used instead of monoalcohol 1 and the AOI was set to 14.9g. The monomer B5 content in the product is 89% by mass.

[Manufacturing Example 3-1] Add 200 g of ethyl acetate into a reaction vessel equipped with a stirrer and a nitrogen introduction tube, and keep it at 70°C. Next, 156.8g of butyl acrylate (hereinafter referred to as BA), 4.0g of acrylic acid (hereinafter referred to as AA), 39.2g of 2-ethylhexyl acrylate (hereinafter referred to as 2-EHA) and 2,2'-azobis(2 , 4-dimethylvaleronitrile) (hereinafter referred to as V-65) 0.2g of a mixed solution was dropped at a constant speed over 2 hours into a reaction vessel maintained at 70±2°C. After the dropping is completed, the mixture is maintained at 70°C ± 2 for 2 hours, and then degassed under reduced pressure at 130°C for 2 hours to remove ethyl acetate and unreacted monomers to obtain polymer A1. The Mw, Mn, Mw/Mn, and glass transition temperature (Tg) of the obtained polymer A1 are listed in the table (the same is true below).

[Manufacturing Example 3-2] Add 100 g of ethyl acetate to a reaction vessel equipped with a stirrer and a nitrogen introduction tube, and maintain it at 70°C. Next, a mixture of 196.0 g of 2-EHA, 4.0 g of AA, and 0.2 g of V-65 was dropped at a constant speed over 2 hours into a reaction vessel maintained at 70±2°C. After the dropping is completed, the mixture is maintained at 70±2°C for 2 hours, and then degassed under reduced pressure at 130°C for 2 hours to remove ethyl acetate and unreacted monomers to obtain polymer A2.

[Manufacturing Example 3-3] Add 100 g of ethyl acetate to a reaction vessel equipped with a stirrer and a nitrogen introduction tube, and maintain it at 70°C. Next, a mixture of 184.0 g of BA, 16.0 g of 4-hydroxybutyl acrylate (hereinafter referred to as 4-HBA) and 0.1 g of V-65 was dropped at a constant speed over 2 hours into a reaction vessel maintained at 70±2°C. . After the dropping is completed, the mixture is maintained at 70±2°C for 2 hours, and then degassed under reduced pressure at 130°C for 2 hours to remove ethyl acetate and unreacted monomers to obtain polymer A3.

[Manufacturing Example 3-4] Add 100 g of ethyl acetate to a reaction vessel equipped with a stirrer and a nitrogen introduction tube, and maintain it at 70°C. Next, a mixture of BA 92.0g, 2-EHA 92.0g, 4-HBA 16.0g and V-65 0.1g was dropped at a constant speed over 2 hours into a reaction vessel maintained at 70±2°C. After the dropping is completed, the mixture is maintained at 70±2°C for 2 hours, and then degassed under reduced pressure at 130°C for 2 hours to remove ethyl acetate and unreacted monomers to obtain polymer A4.

[Table 1]

[Table 2]

[Examples 1~21] Examples 1 to 14 and 21 are examples, and Examples 15 to 20 are comparative examples. All the components were mixed using a planetary mixer (manufactured by EMC Corporation) in the blending (unit: parts by mass) shown in Tables 3 and 4 to produce a curable composition. Cross-linking agent 1 in the table is 1,9-nonanediol diacrylate, cross-linking agent 2 is trimethylolpropane triacrylate, and photopolymerization initiator 1 is 4-methylbenzophenone. Measure or evaluate the items shown in the table using the above measurement methods and evaluation methods. The results are listed in the table.

[table 3]

[Table 4]

As shown in the results in Tables 3 and 4, Examples 1 to 14 containing polymer A and monomer B have low glass transition temperature and low elastic modulus of the cured product, and the laminated body has excellent bending durability and shape recovery. Sex is good for both. The cured product of Example 21 has a low glass transition temperature, and the laminated body has both excellent bending durability and shape recovery properties.

In addition, the entire contents of the specification, patent scope, abstract, and drawings of Japanese Patent Application No. 2019-18959, which was filed on February 5, 2019, are quoted here and incorporated as the disclosure of the specification of the present invention.

1:Kapton film 1a: End of Kapton film 2:Adhesive layer 3: Corona treated PET 3a: End of corona treated PET 4: Offset amplitude from initial value X: shearing direction

Figure 1A is a schematic diagram for explaining the method of measuring creep recovery rate, and is a front view of an example of a sample before a tensile test. Figure 1B is a schematic diagram for explaining the method of measuring creep recovery rate, and is a front view of an example of a sample after a tensile test.

(without)

Claims (16)

A curable composition, including a (meth)acrylate polymer and a first monomer; the number average molecular weight of the aforementioned polymer is 40,000 to 750,000; and the number average molecular weight of the aforementioned first monomer is less than 35,000. , which has more than 1 polyoxyalkylene chain and 1 (meth)acrylyl group in 1 molecule; relative to 100 parts by mass of the aforementioned polymer, the content of the aforementioned first monomer is 10 to 50 parts by mass; Furthermore, the first monomer has one or more urethane bonds in one molecule. The curable composition of claim 1, wherein the glass transition temperature of the first monomer is -55°C or lower. The curable composition of claim 1 or 2, wherein the molecular weight distribution of the first monomer is 1.03~1.2. The curable composition of claim 1 or 2, wherein the first monomer contains 0.3 to 1.9 mass % of urethane bonds relative to the total amount of monomers. The curable composition of claim 1 or 2, wherein the glass transition temperature of the aforementioned polymer obtained by differential scanning calorimeter analysis is -75~-40°C. The curable composition of claim 1 or 2 further contains a cross-linking agent. The curable composition of claim 1 or 2 further contains a photopolymerization initiator. The curable composition of claim 1 or 2, wherein the total content of the aforementioned polymer and the aforementioned first monomer is 80% by mass or more relative to the total amount of the curable composition. A hardened product is a hardened product of the curable composition according to any one of claims 1 to 8. For example, in the hardened material of claim 9, the tan δ peak temperature of dynamic viscoelasticity, that is, the glass transition temperature, is -35°C or less. An adhesive sheet, including an adhesive layer, the adhesive layer is composed of claim 9 or 10 Made of hardened material. Such as the adhesive sheet of claim 11, wherein the thickness of the aforementioned adhesive layer is 10~150 μm. A laminated body having an adhesive layer composed of the hardened material according to claim 9 or 10 and a flexible member laminated through the adhesive layer. The laminate of claim 13, wherein the thickness of the adhesive layer is 10 to 150 μm. The laminate of claim 13 or 14, wherein the flexible member is at least one selected from the group consisting of a surface protection panel, an optical film, a touch panel and a display panel body. A flexible display including the laminate according to any one of claims 13 to 15.

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