WO2015111583A1

WO2015111583A1 - Curable resin composition, and layered body and image display device using curable resin composition

Info

Publication number: WO2015111583A1
Application number: PCT/JP2015/051412
Authority: WO
Inventors: 仁下間; 牧人中村; 明暢中原; 薫小黒
Original assignee: 旭硝子株式会社
Priority date: 2014-01-22
Filing date: 2015-01-20
Publication date: 2015-07-30
Also published as: JP2017048257A; TW201534650A

Abstract

　To provide: a curable resin composition having a high rate of curing, whereby a cured material can be formed with high productivity, and whereby a flexible cured material provided with suitable elastic modulus can be formed; and a layered body and an image display device which use the curable resin composition. A curable resin composition containing: a curable oligomer component containing a curable oligomer (A) having a polybutadiene chain and/or a polyisoprene chain and a urethane bond; a non-curable oligomer (E) having a polybutadiene chain and/or a polyisoprene chain; and a curable monomer (D). A layered body and an image display device which use the curable resin composition.

Description

Curable resin composition, and laminate and image display device using curable resin composition

The present invention relates to a curable resin composition, and a laminate and an image display device using the curable resin composition.

As an image display device, an image display device in which a protective plate is laminated on a display device via a transparent resin layer is known. Also known are transparent panels, laminated glass, and the like in which a transparent resin layer is sandwiched between a pair of transparent substrates.
The transparent resin layer is formed, for example, by a method of curing a curable resin composition containing a curable polymer having a polyisoprene unit as a skeleton, a curable monomer, and a photopolymerization initiator (see Patent Document 1). ). When a curable resin composition containing a curable polymer having a polyisoprene unit as a skeleton is used, the refractive index of the formed transparent resin layer is increased.
A method using a curable resin composition containing a diene oligomer is also known for forming a transparent resin layer (see Patent Document 2).
Patent Document 3 describes a curable resin composition containing a (meth) acrylate oligomer having polyisoprene, polybutadiene, or polyurethane as a skeleton, and a softening component.

JP 2008-282000 A International Publication No. 2012/005169 International Publication No. 2010/027041

However, the curable resin compositions described in Patent Documents 1 to 3 do not necessarily have a high curing rate. Therefore, productivity at the time of forming a transparent resin layer is low.

The present invention provides a curable resin composition capable of forming a cured product having a high curing rate, a cured product with high productivity, and a flexible product having an appropriate elastic modulus to form a laminate. It aims at providing the laminated body and image display apparatus which use curable resin composition.

The present invention provides a curable resin composition having the following configurations [1] to [13], and a laminate and an image display device using the curable resin composition.

[1] A curable oligomer component containing a curable oligomer (A) having at least one of a polybutadiene chain and a polyisoprene chain and a urethane bond;
A non-curable oligomer (E) having at least one of a polybutadiene chain and a polyisoprene chain;
A curable resin composition containing a curable monomer (D).

[2] The curable resin composition according to [1], further including a curable oligomer (B) having at least one of a polybutadiene chain and a polyisoprene chain and having no urethane bond.
[3] The curable oligomer (A), the curable oligomer (B) and the curable monomer (D) each have one or more (meth) acryloyl groups as a curable group in one molecule, [1] or [2] The curable resin composition.
[4] The curable resin composition according to any one of [1] to [3], further comprising a photopolymerization initiator.

[5] The curable resin composition according to any one of [1] to [4], wherein the concentration of urethane bonds in the curable oligomer (A) in the curable resin composition is more than 0 and 3% by mass or less.
[6] The curable resin composition according to any one of [1] to [5], wherein the urethane bond concentration of the curable oligomer (A) is 0.1 to 10% by mass.
[7] The curable resin composition according to any one of [1] to [6], wherein the content of the curable oligomer (A) in 100 parts by mass of the curable oligomer component is 25 to 100 parts by mass.
[8] The curable resin composition according to [2], wherein the total content of the curable oligomer (A) and the curable oligomer (B) in 100 parts by mass of the curable oligomer component is 75 to 100 parts by mass. object.
[9] The curable resin composition according to any one of [1] to [8], comprising 100 to 500 parts by mass of the non-curable oligomer (E) with respect to 100 parts by mass of the curable oligomer component.
[10] The curable resin composition according to any one of [1] to [9], comprising 10 to 500 parts by mass of the monomer (D) with respect to 100 parts by mass of the curable oligomer (A).

[11] The curable oligomer (A) is
A hydroxyl group is added to an isocyanate group-terminated prepolymer obtained by reacting a compound (a1) having at least one of a polybutadiene chain and a polyisoprene chain and a hydroxyl group with a polyisocyanate (a2) at a ratio of an index exceeding 100. An oligomer obtained by reacting a curable monomer having (a3); or
It is an oligomer obtained by reacting a curable monomer having an isocyanate group (a4) with a hydroxyl group-terminated prepolymer obtained by reacting the compound (a1) and the polyisocyanate (a2) at a ratio of 100 or less. The curable resin composition according to any one of [1] to [10].

[12] a display device;
A transparent substrate disposed opposite to the viewing surface side of the display device;
A cured resin layer sandwiched between the display device and the transparent substrate;
A laminate having
The cured resin layer is a laminate in which the curable resin composition according to any one of [1] to [11] is cured.
[13] An image display device having a cured resin layer obtained by curing the curable resin composition of any one of [1] to [11].

According to the present invention, a curable resin composition capable of forming a cured product having a high curing rate, a cured product with high productivity, and a flexible product having an appropriate elastic modulus to form a laminate, And the laminated body and image display apparatus which use this curable resin composition can be provided.

It is sectional drawing which shows 1 process in the manufacturing method of the laminated body of this invention. It is sectional drawing which shows an example of the laminated body manufactured by the method of FIG. It is the graph which plotted the storage shear elastic modulus (G ') with respect to ultraviolet light irradiation time about the curable resin composition of Example 1 and Comparative Example 1. It is the graph which plotted the storage shear elastic modulus (G ') with respect to ultraviolet light irradiation time about the curable resin composition of Example 2 and Comparative Example 2. It is the graph which plotted the degree of hardening with respect to ultraviolet light irradiation time about the curable resin composition of Example 1 and Comparative Example 1. FIG. It is the graph which plotted the degree of hardening with respect to ultraviolet light irradiation time about the curable resin composition of Example 2 and Comparative Example 2. FIG.

In this _{^{specification, CH 2 = C (R 10}} ) C (O) - group represented by ^{(wherein, R 10} represents a hydrogen atom or a methyl group.) Referred to as (meth) acryloyl groups. The (meth) acryloyl group is a general term for an acryloyl group and a methacryloyl group. Similarly, a group represented by CH ₂ ═C (R ¹⁰ ) C (O) O— is referred to as a (meth) acryloyloxy group.
A compound represented by CH ₂ ═C (R ¹⁰ ) C (O) OH is referred to as (meth) acrylic acid. Similarly, an ester of (meth) acrylic acid is referred to as (meth) acrylate.
In addition, the unit represented by the formula (I) is referred to as a unit (I), and the same applies to units represented by other formulas.
The “curability” in the oligomer or monomer in the present invention means a compound having a (meth) acryloyl group unless otherwise specified.
The index when the polyol and the polyisocyanate are reacted is a value obtained by multiplying the ratio obtained by dividing the number of equivalents of the isocyanate group of the polyisocyanate by the number of equivalents of the hydroxyl group of the polyol by 100.
The “urethane bond” is a divalent group (molecular weight: 59) represented by —NHC (═O) O—, and is usually formed by a reaction between an isocyanate group and a hydroxyl group.
In the present invention, “transparent” means a state in which the other surface side can be visually recognized from one surface side in the whole or a part of the substrate or the laminate. Even if the visible light transmittance is low due to absorption, reflection, or optical phase change of a part of the light incident on the substrate or laminate, the state where the other surface side can be seen from one surface side is “transparent” include.

<Curable resin composition>
The curable resin composition of the present invention contains a curable oligomer (A) having at least one of a polybutadiene chain and a polyisoprene chain and a urethane bond (hereinafter also referred to as “oligomer (A)”). A component, a non-curable oligomer (E) having at least one of a polybutadiene chain and a polyisoprene chain (hereinafter also referred to as “oligomer (E)”), a curable monomer (D) (hereinafter referred to as “monomer (D)”) ")").
The oligomer (A) and the monomer (D) each have one or more (meth) acryloyl groups in one molecule as a curable group, and have curability based thereon.
The oligomer (E) does not have a (meth) acryloyl group and therefore does not have curability.

The polybutadiene chain in the oligomer (A) and the oligomer (E) has a unit derived from butadiene (hereinafter also referred to as “butadiene unit”), and the polyisoprene chain is a unit derived from isoprene (hereinafter referred to as “isoprene unit”). ").) The butadiene unit constituting the polybutadiene chain may be a hydrogenated double bond, and the isoprene unit constituting the polyisoprene chain may be a hydrogenated double bond.

The curable resin composition of the present invention can be suitably used for forming a cured resin layer in a laminate having a pair of substrates and a cured resin layer sandwiched between the pair of substrates. As will be described in detail later, for example, the laminated body is a display device and a transparent substrate made of a glass plate, a transparent resin plate, or the like disposed to face the viewing surface side of the display device. The laminated body made is mentioned. Moreover, the transparent laminated body which has a pair of transparent substrate which consists of a glass plate, a transparent resin board, etc. is mentioned.
The curable resin composition of the present invention further includes a cured resin layer in an image display device in which a transparent substrate such as a touch panel or a protective plate is laminated on a display device such as a liquid crystal display device via a cured resin layer. It can be used suitably for formation.

[Oligomer (A)]
(Oligomer (A))
The oligomer (A) is a curable oligomer having at least one of a polybutadiene chain and a polyisoprene chain and a urethane bond. The oligomer (A) preferably has at least one (meth) acryloyl group in one molecule and has an average value of 1 to 4. When the number of (meth) acryloyl groups possessed by the oligomer (A) is not less than the lower limit of the above range, the curable resin composition is sufficiently cured. When it is not more than the upper limit of the above range, it is easy to obtain a cured product having an appropriate elastic modulus and flexibility. If the storage shear modulus of the cured product is 1 × 10 ³ to 1 × 10 ⁵ Pa, the cured product and, for example, the substrate can be bonded with good adhesion. Further, the cured product is excellent in stress absorbability and can prevent warpage of the obtained laminate. In addition, the occurrence of color unevenness can be prevented when the laminate is used in a display device. The oligomer (A) may be a mixture of oligomers having different numbers of (meth) acryloyl groups. The oligomer (A) has one or more (meth) acryloyl groups in one molecule, and the average number of (meth) acryloyl groups in the oligomer (A) is 1.8 to 3 in one molecule. Preferably.
The cured product of the curable resin composition containing the oligomer (A) has a high refractive index due to the oligomer (A) having at least one of a hydrophobic polybutadiene chain and a polyisoprene chain.

The oligomer (A) may have a unit (u1) described later derived from a monomer (m1) other than butadiene and isoprene.

The curable resin composition containing the oligomer (A) has a high curing rate due to the oligomer (A) having a urethane bond. The reason for this is not clear, but it is thought that hydrogen bonding by urethane bonds accelerates intramolecular chain transfer and accelerates the curing rate. When the curing rate of the curable resin composition is high, the productivity when producing a cured product of the curable resin composition or an article provided with the cured product is excellent. Moreover, since the intensity | strength of the light irradiated to curable resin composition at the time of hardening can be made small, the damage by the light irradiation to the board | substrate etc. which comprise articles | goods can be reduced.
Since the oligomer (A) has at least one of a polybutadiene chain and a polyisoprene chain and a urethane bond, the curable resin composition containing the oligomer (A) can produce a cured product having a high refractive index with excellent productivity. Can be formed.

The content of the oligomer (A) in the curable oligomer component is preferably 25 to 100 parts by mass, more preferably 35 to 100 parts by mass, with respect to 100 parts by mass of the curable oligomer component, and 45 to 100 The part by mass is particularly preferred.
Examples of the components other than the oligomer (A) in the curable oligomer component include the curable oligomer (B) and the curable oligomer (C) described later. As components other than the oligomer (A) in the curable oligomer component, the curable oligomer (B) described later is particularly preferable.

The oligomer (A) is preferably contained in a range where the concentration of urethane bonds in 100% by mass of the curable resin composition is more than 0 and 3% by mass or less, more preferably 0.2 to 2.0% by mass. preferable. As the concentration of urethane bonds in the curable resin composition increases, the curing rate of the curable resin composition increases. If the concentration of the urethane bond of the oligomer (A) in the curable resin composition is within the above range, the curing rate of the curable resin composition is sufficiently high, and the elastic modulus of the resulting cured product is appropriate. . Such a cured product of the curable resin composition is preferably used for applications in which the substrates are bonded to each other, for applications in which the display device is bonded to a transparent substrate that is disposed to face the viewing surface of the display device. it can.

A component having a urethane bond other than the oligomer (A) may be contained in the curable resin composition. Examples of such components include a non-curable oligomer (E) having a urethane bond and a curable oligomer (C) having a urethane bond described below. Therefore, when a component having a urethane bond other than the oligomer (A) is contained in the curable resin composition, the urethane bond is also adjusted to the concentration of all the urethane bonds in the curable resin composition. Contribute. In that case, the density | concentration of all the urethane bonds in curable resin composition is calculated based on the compounding quantity of the component which has a urethane bond contained in curable resin composition. *

The concentration of the urethane bond of the oligomer (A) in the curable resin composition is a mass ratio of the urethane bond of the oligomer (A) when the mass of the curable resin composition is 100% by mass.
The concentration of all urethane bonds in the curable resin composition is preferably in the range of more than 0 and 4% by mass or less, more preferably 0.2 to 3.5% by mass.
The curable resin composition of the present invention preferably contains substantially no components having a urethane bond other than the oligomer (A). In this case, the urethane bond concentration of the curable resin composition of the present invention is calculated by the urethane bond content of the oligomer (A) and the content of the oligomer (A) in the curable resin composition.

The concentration of the urethane bond in the oligomer (A) is preferably 0.1 to 10% by mass, and more preferably 0.3 to 9% by mass. If the concentration of the urethane bond is not less than the lower limit of the above range, the curing rate can be increased. If it is not more than the upper limit of the above range, an appropriate elastic modulus can be obtained for the cured product of the curable resin composition. For example, in an image display device, the display device is disposed opposite to the viewing surface side of the display device. Adhesion with the transparent substrate can be improved. Moreover, it is excellent also in stress absorption.

The concentration of the urethane bond of the oligomer (A) can be adjusted by a method of controlling the ratio of each compound used when the oligomer (A) is produced. For example, a method for controlling the index of a compound (a1) having at least one of a polybutadiene chain and polyisoprene chain described later and a hydroxyl group and a polyisocyanate (a2) described later; having an isocyanate group-terminated prepolymer and a hydroxyl group described later It can adjust by the method of controlling the index with a curable monomer (a3), or the index with the hydroxyl-terminated prepolymer mentioned later and the curable monomer (a4) which has an isocyanate group.

The concentration of the urethane bond of the oligomer (A) is a mass ratio of the urethane bond to the mass of the oligomer (A), and is calculated from the amount of each component used for the production of the oligomer (A).

The number average molecular weight in terms of polystyrene by GPC of the oligomer (A) is preferably 2,000 to 500,000, more preferably 2,400 to 100,000. When the number average molecular weight of the oligomer (A) is not less than the lower limit of the above range, the cured product of the curable resin composition tends to have an appropriate elastic modulus, and when it is not more than the upper limit, the curing rate can be increased.

Among the oligomers (A), as the oligomer having a polybutadiene chain, for example, the skeleton has a unit composed of at least one of the unit represented by the following formula (I) and the unit represented by the following formula (II). In addition, an oligomer (A1) having a group represented by the following formula (III) (a monovalent group having a (meth) acryloyloxy group) at at least one terminal of the molecule is exemplified. Unit (I) is a unit with 1,4 bonds, and unit (II) is a unit with 1,2 bonds.
The other end of the molecule of the oligomer (A1) may be a group represented by the above formula (III), another monovalent group such as a hydroxyl group, or a hydrogen atom. From the viewpoint of excellent curability of the curable resin composition, the other end of the oligomer (A1) is preferably a group represented by the above formula (III).

In formula (I) and formula (II), the solid and dotted double line portions indicate single bonds or double bonds. In the case of a single bond, the single bond is a hydrogenated double bond.
In the formula (III), R ¹ to R ³ each independently has a linear or branched alkylene group having 1 to 10 carbon atoms or an alkyl group having 1 to 6 carbon atoms as a substituent. Any one of a cycloalkylene group having 3 to 8 carbon atoms and a combination of the above-described alkylene group and cycloalkylene group.
R ⁴ represents a hydrogen atom or a methyl group.

In the formula (III), R ¹ represents a group obtained by removing the hydroxyl group from the hydroxyl group end group of the polybutadiene chain end.
R ² represents a divalent group obtained by removing an isocyanate group from diisocyanate. R ² is a hexamethylene group, a methylene-1,3,3-trimethylcyclohexylene group, a methylenebis (cyclohexane-4,1-diyl) group in terms of non-yellowing of the cured product of the curable resin composition. And m-phenylene bismethylene group is preferred.
R ³ and R ⁴ are groups derived from the curable monomer (a3) described later, and among the above, R ³ is preferably an alkylene group having 1 to 6 carbon atoms from the viewpoint of imparting flexibility.

Among the oligomers (A), as the oligomer having a polyisoprene chain, for example, a unit composed of at least one of a unit represented by the following formula (IV) and a unit represented by the following formula (V) is used as a skeleton: And an oligomer (A2) having a group represented by the above formula (III) at least at one end of the molecule. The unit (IV) is a unit with 1,4 bonds, and the unit (V) is a unit with 1,2 bonds.
The other end of the molecule of the oligomer (A2) may be a group represented by the above formula (III), another monovalent group such as a hydroxyl group, or a hydrogen atom. From the viewpoint of excellent curability of the curable resin composition, the other end of the oligomer (A2) is preferably a group represented by the above formula (III).

In formula (IV) and formula (V), the double line part of a solid line and a dotted line shows a single bond or a double bond. In the case of a single bond, the single bond is a hydrogenated double bond.
The ratio of the unit (I) to the unit (II) in the skeleton of the oligomer (A1) is not limited, and the skeleton composed only of the unit (I) or the skeleton composed only of the unit (II) It may be a skeleton composed of the unit (II).
The ratio of the unit (IV) to the unit (V) in the skeleton of the oligomer (A2) is not limited, and the skeleton consisting only of the unit (IV) or the skeleton consisting only of the unit (V) It may be a skeleton consisting of the unit (V).

(Method for producing oligomer (A))
The oligomer (A) can be produced by reacting a curable monomer having a hydroxyl group (a3) or a curable monomer having an isocyanate group (a4) with an isocyanate group-terminated prepolymer or a hydroxyl group-terminated prepolymer.
Specifically, it can be produced by the following method.
(1) In the presence or absence of a catalyst, a compound (a1) having at least one of a polybutadiene chain and a polyisoprene chain and a hydroxyl group and a polyisocyanate (a2) having a plurality of isocyanate groups have an index of more than 100 To obtain an isocyanate group-terminated prepolymer by reacting at a ratio (isocyanate group is excessive with respect to the hydroxyl group), and reacting the isocyanate group-terminated prepolymer with a curable monomer (a3) having a hydroxyl group.
According to the method (1), the oligomer (A1) or (A2) having a group represented by the above formula (III) at the terminal can be produced.

(2) In the presence or absence of a catalyst, the above compound (a1) and the above polyisocyanate (a2) are reacted at a ratio that the index is 100 or less (the hydroxyl group is the same mole or excess with respect to the isocyanate group). To obtain a hydroxyl group-terminated prepolymer and react the curable monomer (a4) having an isocyanate group with the hydroxyl group-terminated prepolymer.
According to the method (2), the oligomer (A1) or (A2) having a group represented by the following formula (VI) at the terminal can be produced.

In formula (VI), R ⁷ represents a hydrogen atom or a methyl group, R ⁸ represents a linear or branched alkylene group having 1 to 10 carbon atoms, and an alkyl group having 1 to 6 carbon atoms as a substituent. It represents any of a cycloalkylene group having 3 to 8 carbon atoms which may have, a composite group of the above-described alkylene group and cycloalkylene group. R ⁷ and R ⁸ are groups derived from the curable monomer (a4) described later. R ⁸ is preferably an alkylene group having 2 to 4 carbon atoms.
R ⁹ is a group obtained by removing the hydroxyl group from the terminal group of the hydroxyl group-terminated prepolymer.

That is, the oligomer (A) is an oligomer reacted with a curable monomer (a3) having a hydroxyl group when the prepolymer end is an isocyanate group, and has an isocyanate group when the prepolymer end is a hydroxyl group. It is an oligomer reacted with the curable monomer (a4).
The oligomer (A) can also be produced by the following method.
(3) A method of reacting the compound (a1) after reacting the curable monomer (a3) having a hydroxyl group with the polyisocyanate (a2) in the presence or absence of a catalyst.
The method of (1) and (2) is preferable at the point which makes it easy to make the molecular weight of the oligomer (A) obtained. When the molecular weight is constant, the reactivity of the oligomer (A) can be made uniform, and the elastic modulus of the resulting cured product can be easily controlled.

The compound (a1) preferably has one or more hydroxyl groups in one molecule and has an average value of 1 to 4. If the number of hydroxyl groups is not less than the lower limit of the above range, a cured product having an appropriate elastic modulus can be obtained. If the number of hydroxyl groups is not more than the upper limit of the above range, excessive thickening and gelation during the production of the oligomer (A) can be achieved. Can be prevented. The hydroxyl value (OHV) of the compound (a1) is preferably 225 to 11 mgKOH / g, more preferably 113 to 14 mgKOH / g, from the viewpoint of reactivity. In this specification, the hydroxyl value can be measured by determining the number of mg of potassium hydroxide required to acetylate the hydroxyl group contained in 1 g of the sample. The number average molecular weight in terms of polystyrene by GPC of the compound (a1) is preferably from 500 to 10,000, more preferably from 1,000 to 8,000, from the viewpoint of reactivity.

Among the compounds (a1), the compound having a polybutadiene chain is a compound having a unit consisting of at least one of the unit (I) and the unit (II) and having a hydroxyl group at at least one terminal of the molecule ( a11). The number of hydroxyl groups in the compound (a11) is preferably 1 to 2 on average.
Among the compounds (a1), as the compound having a polyisoprene chain, a compound having a unit consisting of at least one of the unit (IV) and the unit (V) and having a hydroxyl group at at least one terminal of the molecule (A12). The number of hydroxyl groups in the compound (a12) is preferably 1 to 2 on average.

Compound (a11) can be produced, for example, by polymerizing butadiene to obtain a polymer, hydrogenating as required, and then introducing a hydroxyl group into the terminal of the polymer molecule.
As a method of polymerizing butadiene,
(Α) A method of polymerizing butadiene in a solution with a Ziegler catalyst, a lithium catalyst or a radical polymerization initiator; and (β) a method of polymerizing butadiene in a solution in the presence of a sodium catalyst.

According to the method (α), a polymer in which butadiene is mainly polymerized with 1,4-bonds can be obtained. According to the method for polymerizing butadiene in (β), butadiene is mainly composed of 1,2-bonds. A polymer polymerized with can be obtained.

Compound (a12) can be produced, for example, by polymerizing isoprene to obtain a polymer, hydrogenating as required, and then introducing a hydroxyl group into the terminal of the polymer molecule.
As a method for polymerizing isoprene, isoprene may be used in place of butadiene in the methods (α) and (β).

Examples of the method for introducing a hydroxyl group into the polymer molecule end include a method of adding an epoxy compound to a reaction solution containing a polymer obtained by polymerizing butadiene or isoprene. Examples of the epoxy compound include ethylene oxide and propylene oxide. A compound (a1) may be used individually by 1 type, or may use 2 or more types together.

The compound (a1) may have a unit (u1) derived from a monomer (m1) other than butadiene and isoprene.
Examples of the monomer (m1) include α-olefins such as ethylene, propylene, butene-1, pentene-1,2-methylpentene-1, hexene-1,3-methylhexene-1, cyclohexene; styrene, 4 -Styrene monomers such as methylstyrene and α-methylstyrene; Ethylenically unsaturated carboxylic acids such as acrylic acid and methacrylic acid; Methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, acrylic acid Ethylenically unsaturated carboxylic acid esters such as 2-ethylhexyl, dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate Acrylonitrile, me Ethylenically unsaturated carboxylic acid derivatives such as acrylonitrile, acrylamide, and methacryloamide; Unsaturated monoolefins such as ethylene, propylene, and butylene; Halogenated vinyl monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride; Vinyl acetate, Vinyl esters such as vinyl propionate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketone monomers such as vinyl methyl ketone and methyl isopropenyl ketone; containing 2-vinyl pyridine, 4-vinyl pyridine, N-vinyl pyrrolidone, etc. Examples thereof include monovinyl monomers such as nitrogen vinyl monomers.
A monomer (m1) may be used individually by 1 type, or may use 2 or more types together.

When the compound (a1) has a unit (u1), the amount of the monomer (m1) used is 100 parts by mass or less with respect to 100 parts by mass of butadiene and isoprene used in the polymerization reaction of butadiene and isoprene. Preferably, it is more preferably 50 parts by mass or less, and particularly preferably 10 parts by mass or less.

As the polyisocyanate (a2), non-yellowing polyisocyanate is preferable, and non-yellowing diisocyanate having two isocyanate groups is more preferable. The non-yellowing type polyisocyanate means a polyisocyanate compound having no isocyanate group directly bonded to the carbon atom constituting the aromatic nucleus. Examples of the non-yellowing polyisocyanate include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates that do not have an isocyanate group directly bonded to a carbon atom constituting an aromatic nucleus, and the like.
Specifically, for example, aliphatic diisocyanates such as hexamethylene diisocyanate, 1,2-cyclopropanediyl diisocyanate, 1,3-cyclobutanediyl diisocyanate, 1,4-cyclohexanediyl diisocyanate, 1,3-cyclohexanediyl diisocyanate, isophorone Examples thereof include alicyclic diisocyanates such as diisocyanate, 4-methyl-cyclohexane-1,3-diyl-diisocyanate, and dicyclohexylmethane diisocyanate, and non-yellowing aromatic diisocyanates such as xylene diisocyanate.
Moreover, the prepolymer modified body of these diisocyanates, a nurate modified body, a urea modified body, a carbodiimide modified body, etc. are mentioned.
Among these, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylene diisocyanate, norbornane diisocyanate, trimethylhexamethylene diisocyanate, and prepolymer modified products thereof, nurate modified products, urea modified products, carbodiimide modified products, and the like are preferable. Of these, isophorone diisocyanate and hexamethylene diisocyanate are particularly preferable.
Polyisocyanate (a2) may be used individually by 1 type, or may use 2 or more types together.

As the curable monomer (a3), hydroxyalkyl (meth) acrylate is preferable. As the hydroxyalkyl group, a linear or branched hydroxyalkyl group having 1 to 10 carbon atoms is preferable, and a hydroxyalkyl group having 1 to 6 carbon atoms is particularly preferable.
Examples of the curable monomer (a3) include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxy-n-propyl (meth) acrylate, and 2-hydroxy-n-propyl (meth) acrylate. 2-hydroxyisopropyl (meth) acrylate, 4-hydroxy-n-butyl acrylate, 2-hydroxy-n-butyl acrylate, 3-hydroxy-n-butyl acrylate, 5-hydroxy-n-pentyl (meth) acrylate, 2 -Hydroxy-n-pentyl (meth) acrylate, 3-hydroxy-n-pentyl (meth) acrylate, 4-hydroxy-n-pentyl (meth) acrylate, 2-hydroxycyclopropyl (meth) acrylate, 3-hydroxycyclopenty (Meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate and the like.
As the curable monomer (a3), hydroxymethyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate are preferable in terms of reactivity.
A curable monomer (a3) may be used individually by 1 type, or may use 2 or more types together.

The curable monomer (a4) is a compound having an isocyanate group and a (meth) acryloyl group in the molecule, and is preferably an isocyanate alkyl (meth) acrylate. The alkyl part of the isocyanate alkyl preferably has 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms. For example, 2-isocyanate ethyl methacrylate (“Karenz MOI (registered trademark)” manufactured by Showa Denko KK), 2-isocyanate ethyl acrylate (“Karenz AOI (registered trademark)” manufactured by Showa Denko KK), etc. Is mentioned.
A curable monomer (a4) may be used individually by 1 type, or may use 2 or more types together.

When the oligomer (A) is produced by the method (1), the index when the compound (a1) and the polyisocyanate (a2) are reacted is preferably more than 100 and 200 or less, more preferably 110 to 190. 120 to 185 is preferred, and particularly preferred. When the index is in the above range, the curable resin composition containing the obtained oligomer (A) is excellent in the curing rate.
The amount of the curable monomer (a3) used is 100 times the value obtained by dividing the equivalent number of isocyanate groups of the polyisocyanate (a2) by the total number of equivalents of hydroxyl groups of the compound (a1) and the curable monomer (a3). The amount is preferably 90-100.

When the oligomer (A) is produced by the method (2) above, the index when the compound (a1) and the polyisocyanate (a2) are reacted is preferably 50 or more and less than 100, more preferably 51 to 95. 52 to 91 are particularly preferred. When the index is in the above range, the curable resin composition containing the obtained oligomer (A) is excellent in the curing rate.
The amount of the curable monomer (a4) used is such that the isocyanate group index of the curable monomer (a4) with respect to the hydroxyl group of the prepolymer obtained by reacting the compound (a1) with the polyisocyanate (a2) is 90 to 100 is preferable.

Catalysts include monoamines such as triethylamine, N, N-dimethylcyclohexylamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethylpropanediamine, N, N , N ′, N′-tetramethylhexanediamine and the like, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, N, N, N ′, N ″, N ″ -pentamethyldipropylene Triamines such as triamine and tetramethylguanidine, triethylenediamine, N, N-dimethylpiperazine, N-methyl-N ′-(2-dimethylamino) -ethylpiperazine, N-methylmorpholine, N- (N ′, N ′ -Dimethylaminoethyl) morpholine, cyclic amines such as 1,2-dimethylimidazole, dimethylaminoethanol, dimethylamino Alcohol amines such as ethoxyethanol, N, N, N′-trimethylaminoethylethanolamine, N-methyl-N ′-(2-hydroxyethyl) piperazine, N- (2-hydroxyethyl) morpholine, bis (2- Ether amines such as dimethylaminoethyl) ether and ethylene glycol bis (3-dimethyl) aminopropyl ether, and the metal catalyst is an organometallic compound such as stannous diacetate, stannous octoate, stannous dilaurate, Dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin distearate, dioctyltin dilaurate, dibutyltin marker, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin Captide, dioctyltin thiocarboxylate, tetrabutoxytitanium, tetraisopropoxytitanium, bismuth tris (2-ethylhexanoate), bismuth octylate, bismuth neodecanoate, lead octoate, lead naphthenate, nickel naphthenate, naphthenic acid Examples include cobalt and carboxylic acid salts.
A catalyst may be used individually by 1 type, or may use 2 or more types together.
The amount of the catalyst used is preferably in the range of 0.01 to 3.0 parts by weight for tertiary amine catalysts and 100 parts by weight for metal catalysts based on 100 parts by weight of polydiene polyol (a1). The range of 0.001 to 0.1 parts by mass is preferable.

The reaction of compound (a1), polyisocyanate (a2) and curable monomer (a3) or (a4) is carried out without solvent or in a suitable inert solvent. Usually, it is carried out in the absence of a solvent. Examples of the inert solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; ester solvents such as methyl acetate, ethyl acetate, and n-propyl acetate; methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, Monomers such as styrene and propylene; amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone; such as diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane and 1,4-dioxane Examples thereof include ether solvents; nitrile solvents such as acetonitrile and benzonitrile; dimethyl sulfoxide; phosphoric acid amide solvents such as hexamethylphosphorotriamide (HMPT) and hexamethylphosphoroamide (HMPA).
The reaction temperature is preferably 0 ° C to 100 ° C, more preferably 40 to 80 ° C. The reaction is usually completed in several minutes to several hours.

[Oligomer (E)]
The oligomer (E) is a non-curable oligomer having at least one of a polybutadiene chain and a polyisoprene chain and having no curability. The oligomer (E) does not have a (meth) acryloyl group.
Moreover, although the oligomer (E) may have a urethane bond, it is preferable that it is a compound which does not have a urethane bond. Examples of the oligomer (E) having a urethane bond include a hydroxyl group-terminated prepolymer used for the production of the curable oligomer (A) before reacting with the curable monomer (a4).
By containing an oligomer (E), the viscosity of a curable resin composition falls and the handleability of a curable resin composition is excellent. Moreover, the hardened | cured material which has a moderate elasticity modulus and has a softness | flexibility can be formed by containing an oligomer (E). The hardened | cured material which has a softness | flexibility is suitable for the cured resin layer formed between a display device and the transparent substrate opposingly arranged by the visual recognition surface side of this display device, for example. Since the oligomer (E) has at least one of a polybutadiene chain and a polyisoprene chain, it has excellent compatibility with the oligomer (A). Since the compatibility is excellent, the above-described effects can be sufficiently obtained by blending the oligomer (E).

The number average molecular weight in terms of polystyrene by GPC of the oligomer (E) is preferably 500 to 50,000, more preferably 1,000 to 30,000. If the number average molecular weight of the oligomer (E) is not less than the lower limit of the above range, the oligomer (E) is difficult to bleed out in the cured product, and if it is not more than the upper limit, a viscosity reducing effect is easily obtained.

Among the oligomers (E), examples of the oligomer having a polybutadiene chain include an oligomer (E1) having a unit composed of at least one of the unit (I) and the unit (II). The oligomer having a polybutadiene chain can be produced by, for example, (α) and (β) of the method for polymerizing butadiene described above.
Among oligomers (E), examples of the oligomer having a polyisoprene chain include an oligomer (E2) having a unit composed of at least one of the unit (IV) and the unit (V). The oligomer having a polyisoprene chain can be produced, for example, by using isoprene instead of butadiene in (α) and (β) of the method for polymerizing butadiene.

The ratio of the unit (I) to the unit (II) in the skeleton of the oligomer (E1) is not limited, and the skeleton consisting only of the unit (I) or the skeleton consisting only of the unit (II) It may be a skeleton composed of the unit (II).
The ratio of the unit (IV) to the unit (V) in the skeleton of the oligomer (E2) is not limited, and the skeleton consisting only of the unit (IV) or the skeleton consisting only of the unit (V) It may be a skeleton consisting of the unit (V).

The oligomer (E) may have a unit (u1) derived from a monomer (m1) other than butadiene and isoprene.
When the oligomer (E) has the unit (u1), the amount of the monomer (m1) used is 400 parts by mass or less with respect to 100 parts by mass of butadiene and isoprene used in the polymerization reaction of butadiene and isoprene. preferable.

The oligomer (E) is preferably contained in the curable resin composition in an amount of 100 to 500 parts by mass with respect to a total of 100 parts by mass of the curable oligomer component composed of the oligomer (A) and the oligomer (B) described later. More preferably, it is contained in an amount of 150 to 400 parts by mass, particularly preferably 200 to 350 parts by mass. If content of an oligomer (E) is more than the lower limit of the said range, the viscosity of curable resin composition will fully fall and the handleability of curable resin composition will be excellent. Moreover, the hardened | cured material which has a moderate elasticity modulus and has a softness | flexibility can be formed by containing an oligomer (E). If it is below the upper limit of the said range, the bleed-out of the oligomer (E) in hardened | cured material can be prevented, and the elasticity modulus of hardened | cured material does not become low too much.
The curable oligomer component includes an oligomer (B) described later as needed in addition to the oligomer (A).

Examples of commercially available oligomers (E) include “Ricon 156 (trade name)” (number average molecular weight: 2500) manufactured by Clay Valley, “Polyoil 110 (trade name)” (number average molecular weight: 1600) manufactured by Nippon Zeon. Is mentioned.

[Monomer (D)]
The monomer (D) is a curable monomer. By containing a monomer (D), the viscosity of a curable resin composition falls and the handleability of a curable resin composition is excellent. Moreover, by containing the monomer (D), the number of curable functional groups can be adjusted so that the elastic modulus of the obtained cured product falls within an appropriate range. Monomer (D) has at least one (meth) acryloyl group in one molecule, and preferably has one.

The molecular weight of the monomer (D) is preferably 100 to 1000. If the molecular weight is not less than the lower limit of the above range, flexibility is easily obtained, and if it is not more than the upper limit of the above range, the viscosity is likely to be lowered.

As the monomer (D), at least one of a monomer (D1) having a hydroxyl group and a monomer (D2) having no hydroxyl group can be used. By using the monomer (D1) having a hydroxyl group, the adhesion of the cured product to the substrate or the like is improved. By using the monomer (D2) having no hydroxyl group, a cured product having a higher refractive index can be formed.
Examples of the monomer (D1) having a hydroxyl group include the monomers exemplified above as the curable monomer (a3), polyalkylene glycol mono (meth) acrylate, and the like. Of these, 2-hydroxy-n-propyl (meth) acrylate is preferable because it is an inexpensive general-purpose product.
As the monomer (D1) having a hydroxyl group, one type may be used alone, or two or more types may be used in combination.

Monomers (D2) having no hydroxyl group include acryloylmorpholine, methyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, isobutyl (meth) acrylate, and (meth) acrylic. Cyclohexyl acid, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, mono- or di (meth) acrylate of (poly) ethylene glycol, (poly) Propylene glycol mono- or di (meth) acrylate, 1,4-butanediol mono- or di- (meth) acrylate, trimethylolpropane mono-, di- or tri- (meth) acrylate, glycidyl methacrylate, diethylaminoethyl Acrylate Unsaturated carboxylic acid esters such as dicyclopentenyloxyethyl (meth) acrylate.
The monomer (D2) having no hydroxyl group may be used alone or in combination of two or more.

The monomer (D) is preferably contained in an amount of 10 to 500 parts by weight, more preferably 30 to 300 parts by weight, more preferably 50 to 150 parts by weight based on 100 parts by weight of the oligomer (A) in the curable resin composition. It is particularly preferable that a part by mass is included. If content of a monomer (D) is more than the lower limit of the said range, the viscosity of curable resin composition will fully fall and the handleability of curable resin composition will be excellent. Moreover, the hardened | cured material which has a moderate elasticity modulus and has a softness | flexibility can be formed by containing a monomer (D). If it is below the upper limit of the said range, an excessive elastic modulus raise can be prevented.

[Curable oligomer (B)]
The curable resin composition of the present invention contains a curable oligomer (B) other than the curable oligomer (A) (hereinafter also referred to as “oligomer (B)”) for the purpose of improving the compatibility of the composition. May be. The oligomer (B) preferably has at least one (meth) acryloyl group in one molecule and has an average value of 2 to 3.
The oligomer (B) is a curable oligomer having at least one of a polybutadiene chain and a polyisoprene chain and having no urethane bond. The oligomer (B) is particularly preferable as a curable oligomer component other than the oligomer (A) from the viewpoint of excellent compatibility with the oligomer (A) and the oligomer (E).
Examples of the oligomer (B) include a curable oligomer having a polybutadiene chain (hereinafter also referred to as “oligomer (Bb)”) and a curable oligomer having a polyisoprene chain (hereinafter also referred to as “(Bi)”). It is done.

The content of the oligomer (B) in the curable oligomer component is preferably 0 to 75 parts by mass, more preferably 0 to 65 parts by mass, and more preferably 0 to 55 parts by mass with respect to 100 parts by mass of the curable oligomer component. The part by mass is particularly preferred.
Further, the total content of the oligomer (A) and the oligomer (B) in the curable oligomer component is preferably 75 to 100 parts by mass, and 85 to 100 parts by mass with respect to 100 parts by mass of the curable oligomer component. More preferably, it is 95 to 100 parts by mass.

The number average molecular weight in terms of polystyrene by GPC of the oligomer (B) is preferably 1,000 to 50,000, more preferably 2,000 to 40,000, and most preferably 2,000 to 30,000. When the number average molecular weight of the oligomer (B) is not less than the lower limit of the above range, flexibility is easily obtained, and when it is not more than the upper limit, an increase in viscosity is easily suppressed.

Among oligomers (B), as oligomer (Bb), for example, carboxylic anhydride such as maleic anhydride is added to polybutadiene having a unit consisting of at least one of unit (I) and unit (II). Examples of the method include obtaining an adduct, esterifying the adduct with the curable monomer (a3) exemplified above, and introducing a (meth) acryloyloxy group. Polybutadiene is obtained by the methods (α) and (β) for polymerizing butadiene in the method for producing the oligomer (a11) described above.
Among the oligomers (B), as the oligomer (Bi), for example, a carboxylic anhydride such as maleic anhydride is added to polyisoprene having a unit consisting of at least one of the unit (IV) and the unit (V). Thus, an adduct is obtained, and the adduct is reacted with the curable monomer (a3) exemplified above to introduce a (meth) acryloyloxy group. Polyisoprene may be used in place of butadiene in the methods (α) and (β) for polymerizing butadiene in the method for producing oligomer (a11) described above.

The ratio of the unit (I) to the unit (II) in the skeleton of the oligomer (Bb) is not limited, and the skeleton composed only of the unit (I) or the skeleton composed only of the unit (II) It may be a skeleton composed of the unit (II).
The ratio of the unit (IV) to the unit (V) in the skeleton of the oligomer (Bi) is not limited, and the skeleton composed only of the unit (IV) or the skeleton composed only of the unit (V) It may be a skeleton consisting of the unit (V).

The oligomer (B) may have a unit (u1) derived from a monomer (m1) other than butadiene and isoprene.
When the oligomer (B) has a unit (u1), the amount of the monomer (m1) used is 100 parts by mass or less with respect to 100 parts by mass of butadiene and isoprene used in the polymerization reaction of butadiene and isoprene. Preferably, it is more preferably 50 parts by mass or less, and particularly preferably 10 parts by mass or less.

A commercially available oligomer (B) is a curable oligomer having a polybutadiene chain, “Kuraprene (registered trademark) UC203” manufactured by Kuraray (number average molecular weight: 35,000, number of (meth) acryloyl groups: 3). “BAC45 (trade name)” (number average molecular weight: 3,000, number of (meth) acryloyl groups: 2) manufactured by Osaka Organic Chemical Industry Co., Ltd.

[Curable oligomer (C)]
The curable oligomer (C) (hereinafter also referred to as “oligomer C”) is a curable oligomer having neither a polybutadiene chain nor a polyisoprene chain. The oligomer (C) preferably has one or more (meth) acryloyl groups in one molecule and has an average value of 2 to 3. The oligomer (C) includes those having a urethane bond and those having no urethane bond.
Examples of the oligomer (C) include a urethane oligomer having a urethane bond and having neither a polybutadiene chain nor a polyisoprene chain; a poly (meth) acrylate of a polyoxyalkylene polyol; a poly (meth) acrylate of a polyester polyol. It is done. When using the urethane oligomer which has a urethane bond and does not have a polybutadiene chain and a polyisoprene chain, it is preferable to use it so that the concentration of the urethane bond in the curable resin composition is within the above range.
As the curable urethane oligomer, for example, an isocyanate-terminated urethane prepolymer is produced from polyoxyalkylene polyol or polyester polyol and polyisocyanate, and a (meth) acrylate having a functional group capable of reacting with an isocyanate group such as a hydroxyl group is prepared. The urethane oligomer obtained by making it react is mentioned. Similarly, a urethane oligomer obtained by producing a hydroxyl group-terminated urethane prepolymer and reacting it with a (meth) acrylate having an isocyanate group can also be used.

The number average molecular weight in terms of polystyrene by GPC of the oligomer (C) is preferably 1,000 to 50,000, more preferably 2,000 to 40,000, and most preferably 2,000 to 30,000. When the number average molecular weight of the oligomer (C) is not less than the lower limit of the above range, flexibility is easily obtained, and when it is not more than the upper limit, an increase in viscosity is easily suppressed.
The oligomer (C) is preferably contained in a range of 100 parts by mass or less, more preferably in a range of 50 parts by mass or less, with respect to 100 parts by mass of the oligomer (A) as necessary.

(Photopolymerization initiator)
The curable resin composition of the present invention preferably contains a photopolymerization initiator. That is, the curable resin composition of the present invention is preferably a photocurable resin composition in which a curing reaction proceeds by light irradiation. In addition, you may mix | blend the hardening | curing agent which generate | occur | produces a radical with a heat instead of a photoinitiator in curable resin composition.
As the photopolymerization initiator, one that is excited by irradiation with visible light or ultraviolet light (wavelength 300 to 400 nm) and activated to accelerate the curing reaction is preferable. Specific examples include benzoin ether photopolymerization initiators, α-hydroxyalkylphenone photopolymerization initiators, and acylphosphine oxide photopolymerization initiators.

Specific examples of the photopolymerization initiator include benzophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, acetophenone, 3-methylacetophenone, benzoyl, benzoin isobutyl ether, benzoin isopropyl ether, Benzoin ethyl ether, anthraquinone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2 -Methyl-1-propan-1-one, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and the like. Among them, 1-hydroxycyclohexyl phenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, bis (2,4,6-trimethyl) Acylphosphine oxide photopolymerization initiators such as benzoyl) -phenylphosphine oxide are preferred. 1-hydroxycyclohexyl phenyl ketone and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide are particularly preferred from the viewpoint that the curable resin composition can be sufficiently cured with a small amount of addition.
A photoinitiator may be used individually by 1 type, or may use 2 or more types together.

The content of the photopolymerization initiator in the curable resin composition is 0.01 to 10 masses per 100 mass parts in total of the oligomer (A), oligomer (B), oligomer (C) and monomer (D). Part is preferable, and 0.1 to 2.5 parts by mass is more preferable.

[Other ingredients]
The curable resin composition of the present invention may contain various additives depending on applications. Additives include UV absorbers (benzotriazoles, hydroxyphenyltriazines, etc.), light stabilizers (hindered amines, etc.), polymerization inhibitors (hydroquinones (2,5-di-tert-butylhydroquinone (hereinafter referred to as “hindered amines”)) , Etc.), catechol (p-tert-butylcatechol, etc.), anthraquinone, phenothiazine, hydroxytoluene, etc.), antioxidant, tackifier (rosin ester, etc.). ), Pigments, dyes, metal oxide fine particles, fillers, and the like.

The curable resin composition of the present invention preferably contains no solvent. When using the curable resin composition of this invention for manufacture of the below-mentioned laminated body, it is not preferable to have volatile components, such as a solvent. However, when the curable resin composition of the present invention is applied to a substrate or the like to form a coating film of the curable resin composition, the coating property is insufficient due to the high viscosity of the curable resin composition. It may be. In that case, a coating property can be improved by adding a solvent to the curable resin composition of the present invention. In this case, the solvent is volatilized and removed from the curable resin composition before the curable resin composition is cured. The temporary use of such a solvent does not mean that the solvent is a component of the curable resin composition of the present invention.
Further, when a solvent is used in the production of the curable oligomer (A), the solvent may be accompanied by the curable oligomer (A) and mixed in a small amount in the curable resin composition. In addition, a small amount of low boiling point compounds may be mixed with the components of the curable resin composition. In such a case, it is preferable to remove the low boiling point solvent or the like before curing the curable resin composition, if necessary.
Note that a very small amount of solvent or the like may remain in the curable resin composition as long as the curing of the curable resin composition is not adversely affected.

The content of other components in 100% by mass of the curable resin composition is preferably 30% by mass or less, and more preferably 25% by mass or less.

[Curable resin composition]
When using a curable resin composition of the present invention to produce a laminate by a production method using a reduced pressure lamination method described later, the area exposed to a reduced pressure atmosphere in the curable resin composition is relatively large. It is preferable that the curable resin composition does not contain a low boiling point compound. Thereby, it is suppressed that the low boiling-point compound in curable resin composition volatilizes, and a composition changes a lot. Moreover, it becomes easy to maintain a desired reduced pressure atmosphere.
In the case of producing a laminate by a production method using a reduced pressure lamination method, the curable resin composition preferably does not contain a component (such as a monomer) having a boiling point of 150 ° C. or less under an atmospheric pressure atmosphere. More preferably, the lower boiling point does not contain a component having a temperature of 200 ° C. or lower.

The viscosity V ₄₀ at 40 ° C. of the curable resin composition of the present invention is preferably 50 Pa · s or less, and more preferably 5 Pa · s or less. If the viscosity V ₄₀ is more than the upper limit, sufficient fluidity can not be obtained, it bubbles hardly occurs in the curable resin composition.
The viscosity V ₂₅ at 25 ° C. of the curable resin composition of the present invention is preferably 0.05 Pa · s or more, and more preferably 0.20 Pa · s or more. The viscosity V ₂₅ is preferably 4.5 Pa · s or less. If the viscosity V ₂₅ is equal to or higher than the lower limit value, it is not necessary to use a large amount of low molecular weight monomer or the like in order to lower the viscosity, and thus the physical properties of the cured product are hardly lowered.
The viscosity is a value measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., RE-85U).
However, when the viscosity of the curable resin composition is 100 Pa · s or less, 1 ° 34 ′ × R24 is used as the rotor, and when the viscosity exceeds 100 Pa · s, 3 ° × R9.7 is used as the rotor. And

The curable resin composition of the present invention described above is non-curable having at least one of a polybutadiene chain and a polyisoprene chain together with a curable oligomer (A) having at least one of a polybutadiene chain and a polyisoprene chain and a urethane bond. An oligomer (E) and a curable monomer (D) are contained. Therefore, the curable resin composition of the present invention has a high curing rate, can form a cured product with high productivity, and can form a cured product having an appropriate elastic modulus and flexibility.
The curable resin composition of the present invention can be used for applications such as an adhesive and a coating agent in addition to the use for forming a cured resin layer in a laminate and an image display device described later.

<Hardened product of curable resin composition>
The curable resin composition of the present invention can be formed into a cured product by, for example, irradiating a curable resin composition containing the above-described amount of the above-described photopolymerization initiator with 500 mJ or more of visible light or ultraviolet rays. it can. When a curing agent that generates radicals by heat is used, a cured product can be obtained by heating at a temperature corresponding to the half-life of the curing agent.
The storage shear modulus of the cured product is preferably 1 × 10 ³ to 1 × 10 ⁵ Pa.
An adhesive film can be obtained by sandwiching both sides of the cured product with a first protective film and a second protective film. The first protective film and the second protective film preferably have different adhesion to the cured product. Examples of the protective film include a PET (Polyethylene Terephthalate) film in which a release agent such as a silicone resin is applied to the surface in contact with the cured product, and a resin material having relatively low adhesion such as polyethylene, polypropylene, and a fluorine resin. A film is preferred.
Moreover, the said hardened | cured material is good also as a transparent surface material with hardened | cured material by laminating | stacking on a transparent substrate. The transparent surface material with a cured product preferably has a protective film on a surface different from the transparent surface material of the cured product. The transparent substrate with an adhesive layer is, for example, a protective plate with an adhesive layer that is bonded to a display panel of a display device. Examples of the transparent substrate include a glass plate, a chemically strengthened glass plate, a transparent resin plate (polycarbonate plate), and the like. The substrate may be a multilayer structure or a single layer structure.
The thickness of the protective plate is 0.5 mm to 25 mm in the case of a glass plate from the viewpoint of mechanical strength and transparency. In applications such as a television receiver and a PC display used indoors, 0.5 mm to 6 mm is preferable from the viewpoint of reducing the weight of the display device, and in public display applications installed outdoors, 3 mm to 20 mm is preferable. When a chemically strengthened glass plate is used as the protective plate, the glass thickness is preferably 0.3 mm to 1.5 mm in terms of strength. When a transparent resin plate is used as the protective plate, it is preferably 2 mm to 10 mm.

<Laminated body and image display device>
The curable resin composition of the present invention can be suitably used for forming a cured resin layer in a laminate having a pair of substrates and a cured resin layer sandwiched between the pair of substrates. As described above, as described above, for example, a laminate in which a display device and a transparent substrate opposed to the viewing surface side of the display device are regarded as a pair of substrates, and the pair of substrates are both transparent substrates. A certain transparent laminated body etc. are mentioned. Thus, as a board | substrate which comprises a laminated body, both a transparent substrate and an opaque board | substrate can be used. Examples of the transparent substrate include a glass plate and a transparent resin plate (polycarbonate plate). The substrate may be a multilayer structure or a single layer structure.
Furthermore, the curable resin composition of the present invention is an image display device in which a transparent substrate such as a touch panel or a protective plate is laminated on a display device such as a liquid crystal display device via a cured resin layer. It can be used suitably for formation.

Examples of the display device include a liquid crystal display device, an organic EL display device, a plasma display device, and an electronic ink display device. These display devices are usually multilayer structures and are opaque as a whole. Therefore, a stacked body in which a display device and a transparent substrate opposed to the viewing surface side of the display device are regarded as a pair of substrates is an opaque stacked body.
However, the display device is usually a multilayer structure, and the display layer (liquid crystal layer, organic EL layer, etc.) and the layer closer to the non-viewing surface than the display layer are opaque, but more visible than the display layer. The surface side layer is usually transparent. Therefore, the surface layer on the viewing surface side of the display device (for example, the outermost layer such as a layer made of a polarizing plate or a layer made of an optical film such as a retardation plate in a liquid crystal display device) is protected transparently through a cured resin layer. In the image display device in which the plates are laminated, when the surface layer on the viewing surface side of the display device is regarded as one substrate and the protective plate is regarded as the other substrate, the surface layer / cured resin layer / protective plate The resulting laminate can be considered a transparent laminate.

In the laminate, when at least one of the pair of substrates is a transparent substrate, a cured resin layer can be formed by irradiating the curable resin composition sandwiched between the substrates through the transparent substrate. When both of the pair of substrates are opaque substrates, the cured resin layer can be formed by heating and curing the curable resin composition.

The image display device of the present invention is an image display device having one or more cured resin layers obtained by curing the curable resin composition of the present invention. For example, in the image display device provided with the touch panel, the cured resin layer acts as an adhesive layer such as between the display device and the touch panel and an adhesive layer such as between the touch panel and a transparent substrate such as a protective plate.
As described above, in the image display device of the present invention, the cured resin layer obtained by curing the curable resin composition of the present invention can be provided between any plate-like or film-like members constituting the image display device. it can.

The cured resin layer is a layer made of a cured product of the curable resin composition of the present invention.
The thickness of the cured resin layer is preferably 0.01 to 0.5 mm, more preferably 0.05 to 0.3 mm. If the thickness of a cured resin layer is more than a lower limit, the mechanical strength of a laminated body will become favorable. If the thickness of a cured resin layer is below an upper limit, a laminated body will become lightweight.

In the laminated body demonstrated above, since the cured resin layer pinched | interposed between a pair of board | substrate consists of hardened | cured material of the curable resin composition of this invention, it is excellent in productivity. Moreover, it has a cured resin layer having an appropriate elastic modulus and flexibility.

[Method for producing laminate]
The above laminate is preferably produced by a production method using a reduced pressure lamination method. The reduced pressure lamination method is disclosed in International Publication No. 2008/081838 and International Publication No. 2009/016943.
The laminate of the present invention, that is, the laminate in which the display device and the transparent substrate opposed to the viewing surface side of the display device are regarded as a pair of substrates, for example, includes the following first step and second step. It can manufacture by the method which has these processes.
First step: In a reduced pressure atmosphere, the curable resin composition of the present invention is sandwiched between a pair of substrates, and the periphery of the curable resin composition between the pair of substrates is sealed with a sealing material. To form a hermetically sealed laminated precursor.
2nd process: The said curable resin composition of the said lamination | stacking precursor is hardened in the atmosphere whose pressure is higher than the said pressure reduction atmosphere.

(First step)
It is not necessary to perform all the operations in the first step under a reduced-pressure atmosphere as long as the curable resin composition is sealed in a reduced-pressure atmosphere to be a laminated precursor. For example, in the case where a sealing material is provided on the entire periphery of one substrate and the other substrate is stacked after the curable resin composition is supplied to the inside of the sealing material on the substrate, the other substrate is stacked. If a reduced-pressure atmosphere is previously used, the previous work may be performed under an atmospheric pressure atmosphere. Further, from the viewpoint of suppressing the generation of bubbles in the curable resin composition, it is preferable to overlap the other substrate after sufficiently exposing the curable resin composition to a reduced pressure atmosphere.
Examples of the sealing material include a double-sided adhesive tape and the curable resin composition of the present invention.

The pressure atmosphere in the first step is preferably a pressure atmosphere of 1 kPa or less, and more preferably a pressure atmosphere of 100 Pa or less. Moreover, since the low boiling point compound in the curable resin composition may volatilize if the pressure in the reduced pressure atmosphere is too low, the reduced pressure atmosphere is preferably a pressure atmosphere of 1 Pa or more, and more preferably a pressure atmosphere of 10 Pa or more. .

The adhesion strength between the pair of substrates and the sealing material is within a range in which gas does not enter from the interface between the substrate and the sealing material when the lamination precursor is placed in an atmosphere having a pressure higher than the reduced-pressure atmosphere in the second step. Good.
For example, the adhesion strength between the substrate and the sealing material can be increased by using a pressure sensitive adhesive. Moreover, the adhesive strength of a board | substrate and a sealing material can be raised by interposing a curable adhesive in the interface of a board | substrate and a sealing material, and hardening this adhesive after forming a lamination | stacking precursor. Further, the adhesion strength between the substrate and the sealing material can also be increased by forming the sealing material with a curable resin and curing the sealing material itself after forming the laminated precursor.

(Second step)
The curable resin composition in the lamination precursor is cured in an atmosphere at a pressure higher than the reduced pressure atmosphere in the first step. When the curable resin composition is thermosetting, it is cured by heating, and when the curable resin composition is photocurable, it is cured by light irradiation. Photocuring can be performed by irradiating light through a transparent substrate from a light source such as an ultraviolet lamp. The cured resin layer is formed by curing the curable resin composition, and a laminate is obtained.
In the production method, it is preferable that a photopolymerization initiator is blended in the curable resin composition and the curable resin composition is cured by light irradiation in the second step.

According to the production method, even if bubbles remain in the curable resin composition in the first step, the bubbles are likely to disappear before the curable resin composition is cured in the second step. No cured resin layer is easily formed. This is due to the following factors.
When the laminated precursor formed in the first step is placed in a pressure atmosphere higher than the reduced pressure atmosphere of the first step in the second step, the pressure outside the transparent substrate becomes larger than the pressure inside, Pressure is applied to the curable resin composition from the substrate. Further, since the inside of the bubbles in the curable resin composition is at the pressure of the reduced pressure atmosphere in the first step, the volume of the bubbles is reduced by the pressure applied to the curable resin composition in the second step, or When the gas in the bubbles dissolves in the curable resin composition, the bubbles disappear.
In order to sufficiently eliminate bubbles in the curable resin composition, in the second step, before curing the curable resin composition, the laminated precursor is held for a while under a pressure atmosphere higher than the reduced-pressure atmosphere. It is preferable to do. The holding time is preferably 5 minutes or more. Note that the holding time may be less than 5 minutes when there are no bubbles or when the bubbles are minute and disappear quickly.

The atmosphere having a higher pressure than the reduced-pressure atmosphere in the second step is preferably a pressure atmosphere of 50 kPa or more, more preferably a pressure atmosphere of 100 kPa or more, and an atmospheric pressure atmosphere is particularly preferable from the viewpoint of easy control of the pressure atmosphere. preferable.
The pressure atmosphere in the first step and the second step is particularly preferably a pressure atmosphere of 100 Pa or less in the first step and an atmospheric pressure atmosphere in the second step.

Hereinafter, an example of a method for manufacturing a laminate will be described with reference to FIG.
In the first step, a sealing material 12 is provided over the entire periphery of one substrate 10 (hereinafter simply referred to as “substrate 10”), and a sealing UV curable resin 36 is applied on the sealing material 12. Then, the curable resin composition 14 is supplied to the surface of the substrate 10 surrounded by the sealing material 12. The layer of the curable resin composition 14 is placed horizontally in the decompression chamber 26 with the layer facing up.
Further, the other substrate 16 (hereinafter simply referred to as “substrate 16”) is held by the suction pad 32 on the upper surface plate 30 that can be moved up and down by the cylinder 34 in the decompression chamber 26, and in parallel above the substrate 10. Make them face each other.
The decompression chamber 26 is closed, and the vacuum pump 28 is operated to evacuate, so that the inside of the decompression chamber 26 has a predetermined decompressed atmosphere.
Thereafter, the cylinder 34 is operated to lower the substrate 16, the layer of the curable resin composition 14 is sandwiched between the substrate 10 and the substrate 16, and the curable resin composition 14 is sealed by the substrate 10, the substrate 16, and the sealing material 12. A laminated precursor is formed.

In the second step, the reduced pressure chamber 26 is returned to the atmospheric pressure atmosphere, the laminated precursor is taken out from the reduced pressure chamber 26, and the curable resin composition of the laminated precursor is heated or irradiated with light in the atmospheric pressure atmosphere. It hardens | cures and the laminated body of FIG. 2 is obtained. In FIG. 2, the code | symbol 21 is a cured resin layer, and the code | symbol 31 is a weir-like part which consists of a sealing material and the hardened | cured material of the ultraviolet curable resin for sealing.

According to the manufacturing method demonstrated above, the laminated body provided with the cured resin layer which has a moderate elasticity modulus and a softness | flexibility can be manufactured with high productivity.
In addition, you may manufacture the laminated body of this invention with well-known manufacturing methods other than an above described manufacturing method.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited by the following description.

Various measurements in the following production examples were performed as follows.
<Measurement method>
[Number average molecular weight of oligomer]
The number average molecular weight (Mn) of the oligomer was determined from a gel permeation chromatogram using HLC-8220GPC manufactured by TOSOH. The sample was a 1.0 mass% THF solution filtered through a 0.45 μm PTFE filter, and two TSKgel GMH _HR manufactured by TOSOH were used for the column.

<Oligomer>
[Production Example 1: Production of oligomer (A1-1)]
Into a four-necked flask equipped with a stirrer, a nitrogen inlet tube, a thermometer and a dropping funnel, as compound (a1), polybutadiene polyol (manufactured by Nippon Soda, “G-2000 (trade name)”, hydroxyl value (OHV) = 52 mg KOH / G, 379.7 parts by mass of the number of hydroxyl groups: 2, number average molecular weight = 1,974), and 78.2 parts by mass of isophorone diisocyanate (hereinafter referred to as “IPDI”) as polyisocyanate (a2). In addition, the reaction was carried out at 80 ° C. for 3 hours in the presence of 0.035 parts by mass of dioctyltin distearate (hereinafter referred to as “DOTDS”) as a catalyst to obtain an isocyanate group-terminated prepolymer. The index when the compound (a1) was reacted with the polyisocyanate (a2) was 183.
Introducing nitrogen and adding 40.9 parts by mass of 2-hydroxyethyl acrylate (hereinafter referred to as “HEA”) as the curable monomer (a3) to the isocyanate group-terminated prepolymer under an air atmosphere, The mixture was stirred at 80 ° C. in the presence of 0.05 part by weight of DTBHQ as a polymerization inhibitor and 0.05 part by weight of dibutyltin dilaurate (hereinafter referred to as “DBTDL”) as a catalyst, and was added to JIS K1603-1. While measuring the isocyanate group content by regular NCO titration, the reaction was continued until the isocyanate group disappeared to obtain an oligomer (A1-1) having a number average molecular weight of 3,000.
In addition, the usage-amount of a curable monomer (a3) is 100 of the value which remove | divided the equivalent number of the isocyanate group of polyisocyanate (a2) by the sum total of the equivalent number of the hydroxyl group of a compound (a1) and a curable monomer (a3). The amount was doubled to 100.
The obtained oligomer (A1-1) was colorless and transparent. Moreover, the average number of acryloyl groups per molecule is 2.0 (the same value as the number of functional groups of isocyanate groups in the isocyanate group-terminated prepolymer), the urethane bond concentration is 8.327% by mass, and the viscosity at 25 ° C. is 800,000 mPa · s.

Since the urethane bond concentration of the oligomer (A1-1) can be considered that the total amount of isocyanate groups of the IPDI (polyisocyanate (a2)) used for the production of the oligomer (A1-1) forms a urethane bond, It can be calculated from the following formula. (Mole number of isocyanate group of IPDI × urethane bond molecular weight (59) / mass of oligomer (A1-1)) × 100 (%)
As the mass of the oligomer (A1-1), the total mass of the charged amounts of polybutadiene polyol, IPDI, and HEA is employed.

[Production Example 2: Production of oligomer (A1-2)]
Into a four-necked flask equipped with a stirrer, a nitrogen introducing tube, a thermometer and a dropping funnel, as a compound (a1), polybutadiene polyol (manufactured by Clay Valley, “LBH-P3000 (trade name)”, hydroxyl value (OHV) = 35.9 mg KOH / g, number of hydroxyl groups: 1.9, number average molecular weight = 2,969) 300 parts by mass, polyisocyanate (a2) as hexamethylene diisocyanate (hereinafter referred to as “HDI”) 14. 96 parts by mass was added and reacted at 80 ° C. for 3 hours in the presence of 0.03 part by mass of DOTDS as a catalyst to obtain a hydroxyl group-terminated prepolymer. The index when polyisocyanate (a2) was reacted with compound (a1) was 88.
To this hydroxyl group-terminated prepolymer, 3.06 parts by mass of 2-isocyanatoethyl acrylate (hereinafter referred to as “Karenz AOI”) is added as a curable monomer (a4), and 0. Stir at 80 ° C. in the presence of 03 parts by mass and 0.05 part by mass of DBTDL as a catalyst, and measure the isocyanate group content by NCO titration in accordance with JIS K1603-1 until the isocyanate groups disappear. Reaction was performed to obtain an oligomer (A1-2) having a number average molecular weight of 58,000.
In addition, the usage-amount of a curable monomer (a4) is as an index of the isocyanate group which the curable monomer (a4) has with respect to the hydroxyl group of the prepolymer obtained by reacting a compound (a1) and a polyisocyanate (a2). It was 98.
The obtained oligomer (A1-2) was colorless and transparent. In addition, the average number of acryloyl groups per molecule is 1.9 (the same value as the number of hydroxyl functional groups in the hydroxyl group-terminated prepolymer), the urethane bond concentration is 3.701% by mass, and the viscosity at 25 ° C. is 500. 000 mPa · s.

The urethane bond concentration of the oligomer (A1-2) is the isocyanate group of the HDI (polyisocyanate (a2)) used in the production of the oligomer (A1-2) and the isocyanate group of the Karenz AOI (curable monomer (a4)). Since the total amount of can be regarded as forming a urethane bond, it can be calculated from the following formula. ((Number of moles of isocyanate group possessed by HDI + number of moles of Karenz AOI) × urethane bond molecular weight (59) / mass of oligomer (A1-2)) × 100 (%)
As the mass of the oligomer (A1-2), the total mass of the charged amounts of polybutadiene polyol, HDI, and Karenz AOI is employed.

[Oligomer (Bi-1)]
Claprene (registered trademark) UC203 (manufactured by Kuraray Co., Ltd.): an oligomer having an isoprene chain and a methacryloyl group and having no urethane bond.

[Oligomer (Bb-1)]
BAC45 (manufactured by Osaka Organic Chemical Industry Co., Ltd.): Terminal acrylic modified 1,4 polybutadiene having no urethane bond.

[Oligomer (E1-1)]
"Ricon 156 (trade name)" manufactured by Clay Valley (number average molecular weight 2,500)
[Oligomer (E1-2)]
“Polyoil110 (trade name)” manufactured by Zeon Corporation (number average molecular weight 1,600)

<Ingredients other than oligomer>
[Monomer having a hydroxyl group (D1)]
2-hydroxypropyl acrylate (hereinafter referred to as “D1-1”, molecular weight: 130.1, viscosity at 25 ° C .: 10 mPa · s)
[Monomer having no hydroxyl group (D2)]
Lauryl acrylate (hereinafter referred to as “D2-1”, molecular weight: 240.4, viscosity at 25 ° C .: 4 to 5 mPa · s)
Acrylylmorpholine (hereinafter referred to as “D2-2”, molecular weight: 141.2, viscosity at 25 ° C .: 12 mPa · s)
Dicyclopentenyloxyethyl methacrylate (hereinafter referred to as “D2-3”, molecular weight: 262, viscosity at 25 ° C .: 17 mPa · s)

(Photopolymerization initiator)
• Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (hereinafter referred to as “Ir819”) manufactured by BASF
1-hydroxy-cyclohexyl-phenyl ketone (hereinafter referred to as “Ir184”) manufactured by BASF
• 2,4,6-Trimethylbenzoyl-phenylphosphine oxide (hereinafter referred to as “TPO”) manufactured by BASF
(Tackifier)
・ Rosin ester (hereinafter referred to as “KE311”) manufactured by Arakawa Chemical Industries, Ltd.
(Polymerization inhibitor)
・ DTBHQ
〔Antioxidant〕
・ Ciba Specialty Chemicals, non-amine hindered phenol antioxidant (hereinafter referred to as “PUR68”)

[Examples 1 and 2, Comparative Examples 1 to 3]
Each component was mixed by the mixture ratio (mass basis) shown in Table 1, and the curable resin composition of each example was prepared.
With respect to the obtained curable resin composition, the curing rate and the storage shear modulus of the cured product were evaluated by the following methods. For Comparative Example 3, only the storage shear modulus was evaluated.
Further, the viscosity V ₂₅ at 25 ° C. of the curable resin composition was measured using an E-type viscometer (RE-85U, manufactured by Toki Sangyo Co., Ltd.).
Table 2 shows the viscosity V ₂₅ at 25 ° C. of the curable resin composition, the storage shear modulus of the cured product, and the concentration of urethane bonds.

(Evaluation method of curing speed)
The curing rate was evaluated from the ultraviolet light (UV) irradiation time required for curing the curable resin composition and achieving a curing degree of 90%. The degree of cure was determined from the measurement result of the storage shear modulus.
The storage shear modulus was measured as follows.
The curable resin composition of each example was sandwiched in a 0.4 mm gap between a soda lime glass stage and a measuring spindle (D-PP20 / AL / S07, manufactured by Anton Paar), and in a nitrogen atmosphere, At 35 ° C., light of 100 mW / cm ² was irradiated for 36 seconds with a mercury xenon lamp (US-9, SP-9) installed at the bottom of the stage. While irradiating with light, 1% dynamic shear strain was applied to cure the curable resin composition. The storage shear modulus at that time was measured with a rheometer (manufactured by Anton Paar, Physica MCR301). Note that the position of the spindle was automatically adjusted so that no stress was generated in the normal direction of the spindle when the curable resin composition was cured.
The irradiation intensity was measured on a stage on which the curable resin composition was installed using an illuminance meter (Ushio Electric Co., Ltd., UV intensity meter Unimeter UIT-101).
The storage shear modulus value after 180 seconds of ultraviolet light irradiation time is defined as the saturated storage shear modulus (G′max), and the storage shear modulus (G ′) for each ultraviolet light irradiation time is normalized based on G′max. Thus, the degree of curing of each composition for evaluation was calculated.
3 and 4 are graphs plotting the storage shear modulus (G ′) versus the ultraviolet light irradiation time for the curable resin compositions of Examples 1 and 2 and Comparative Examples 1 and 2. FIG.
5 and 6 show that the degree of cure (G ′ / G′max) with respect to the ultraviolet light irradiation time for the curable resin compositions of Examples 1 and 2 and Comparative Examples 1 and 2 is 100%. This is a graph plotted as follows.
5 and 6, the ultraviolet irradiation time when the curing degree was 90% was read and used as an index of the curing speed.

(Method for evaluating storage shear modulus)
In the same manner as the method described in “Method of evaluating curing rate” above, a 1% dynamic shear strain was applied while irradiating with light, and the storage shear modulus when the curable resin composition was cured was determined to be rheological. It measured with the meter (The Anton Paar company make, Physica MCR301).
If the storage shear modulus (curing degree 90%) is in the range of 1 × 10 ³ to 1 × 10 ⁵ Pa, the modulus of elasticity is appropriate, and the cured product of the curable resin composition is, for example, a transparent laminate or the like. When used for a cured resin layer (adhesive layer), it can be judged that the film is excellent in flexibility and adhesion, and is excellent in stress absorption.
The results are shown in Table 1.

The curable resin composition of each example had a short ultraviolet irradiation time until the degree of cure reached 90%, and the curing rate was fast (see FIGS. 5 and 6).
Moreover, the cured | curing material of the curable resin composition of each Example had the storage shear elastic modulus in the moderate range (refer Table 2).

Moreover, the laminated body was manufactured as follows using the curable resin composition of Examples 1 and 2 and Comparative Examples 1 and 2.
A liquid crystal display device was taken out from a commercially available liquid crystal display device (7-inch liquid crystal digital photo frame, manufactured by Sony Corporation, product name: DPF-0720). The liquid crystal display device has a display mode of VA (Virtual Alignment) type, a rectangular display, and a vertical (short side) length of 88 mm and a horizontal (long side) length of 156 mm. It was. Polarizers were bonded to both surfaces of the liquid crystal display device, and a printed wiring board was bonded to the end on the long side. The liquid crystal display device was designated as display device A.
A seal part having a thickness of 0.2 mm and a width of 2 mm was formed on the peripheral part of the viewing side surface of the display device A using a double-sided adhesive tape, and each region was obtained in a region surrounded by the seal part. The curable resin composition was applied with a thickness of 0.2 mm. This was placed flat on the upper surface of the lower surface plate in the decompression device in which a pair of surface plate lifting devices are installed so that the surface coated with the curable resin composition is on the upper side.
Separately, a rectangular glass plate B (long side length: 160 mm, short side length 90 mm, thickness: 0.7 mm) is lifted and lowered in the decompression device so as to face the display device A. Installed on the lower surface of the upper surface plate. Moreover, it hold | maintained so that the distance with the display device A might be set to 30 mm in the orthogonal | vertical direction.

Next, the pressure reducing device was sealed and evacuated until the pressure in the pressure reducing device reached about 10 Pa. The upper and lower surface plates are brought close to each other by the lifting device in the decompression device, and the display device A and the glass plate B are pressure-bonded at a pressure of 2 kPa through an uncured layer made of a curable resin composition and held for 1 minute. . In this way, a laminated precursor in which an uncured layer made of the curable resin composition was sandwiched between the display device A and the glass plate B, and the uncured layer was sealed at a peripheral seal portion was formed.
Thereafter, the electrostatic chuck was neutralized to separate the glass plate B from the upper surface plate, and the inside of the decompression device was returned to atmospheric pressure in about 15 seconds.

Subsequently, the laminated precursor was irradiated with ultraviolet rays (light source: Fusion D-bulb metal halide lamp, illuminance: 100 mW / cm ² ) for 36 seconds from the glass plate B side, the uncured layer was cured, and display device A A laminated body in which the glass plate B was bonded to the substrate was obtained.
In the laminates produced using the curable resin compositions of Examples 1 and 2, the curable resin composition was sufficiently cured, but produced using the curable resin compositions of Comparative Examples 1 and 2. In the laminated body, the curable resin composition had an uncured part.

The curable resin composition of the present invention has a high curing rate, can form a cured product with high productivity, and can form a cured product having an appropriate elastic modulus and flexibility.
Therefore, the curable resin composition of the present invention is formed of a cured resin layer for bonding a display device and a transparent substrate opposed to the viewing surface side of the display device, laminated glass, a cured resin layer in a transparent panel, and the like. Is preferably used.
Moreover, the curable resin composition of this invention can be used also for uses, such as an adhesive agent and a coating agent.
Further, the curable resin composition of the present invention is an image display device in which a touch panel or a protective plate is laminated on a display device such as a liquid crystal display device. It is also suitably used for forming a curable resin layer provided as an adhesive layer between materials.
It should be noted that the entire content of the specification, claims, abstract and drawings of Japanese Patent Application No. 2014-9654 filed on January 22, 2014 is cited herein as the disclosure of the specification of the present invention. Incorporated.

DESCRIPTION OF

SYMBOLS

10,16 Board | substrate 12 Sealing material 14 Curable resin composition 21 Cured resin layer 26 Depressurization chamber 28 Vacuum pump 30 Upper surface plate 31 Weir-shaped part 32 Adsorption pad 34 Cylinder 36 UV curable resin for sealing

Claims

A curable oligomer component containing a curable oligomer (A) having at least one of a polybutadiene chain and a polyisoprene chain and a urethane bond;
A non-curable oligomer (E) having at least one of a polybutadiene chain and a polyisoprene chain;
A curable resin composition containing a curable monomer (D).
The curable resin composition according to claim 1, further comprising a curable oligomer (B) having at least one of a polybutadiene chain and a polyisoprene chain and having no urethane bond.
The curable oligomer (A), the curable oligomer (B), and the curable monomer (D) each have at least one (meth) acryloyl group as a curable group in one molecule. Curable resin composition.
The curable resin composition according to any one of claims 1 to 3, further comprising a photopolymerization initiator.
The curable resin composition according to any one of claims 1 to 4, wherein the concentration of urethane bonds of the curable oligomer (A) in the curable resin composition is more than 0 and 3% by mass or less.
The curable resin composition according to any one of claims 1 to 5, wherein the concentration of urethane bonds in the curable oligomer (A) is 0.1 to 10% by mass.
The curable resin composition according to any one of claims 1 to 6, wherein the content of the curable oligomer (A) in 100 parts by mass of the curable oligomer component is 25 to 100 parts by mass.
The curable resin composition according to claim 2, wherein the total content of the curable oligomer (A) and the curable oligomer (B) in 100 parts by mass of the curable oligomer component is 75 to 100 parts by mass. .
The curable resin composition according to any one of claims 1 to 8, comprising 100 to 500 parts by mass of the non-curable oligomer (E) with respect to 100 parts by mass of the curable oligomer component.
The curable resin composition according to any one of claims 1 to 9, comprising 10 to 500 parts by mass of the monomer (D) with respect to 100 parts by mass of the curable oligomer (A).
The curable oligomer (A) is
A hydroxyl group is added to an isocyanate group-terminated prepolymer obtained by reacting a compound (a1) having at least one of a polybutadiene chain and a polyisoprene chain and a hydroxyl group with a polyisocyanate (a2) at a ratio of an index exceeding 100. An oligomer obtained by reacting a curable monomer having (a3); or
It is an oligomer obtained by reacting a curable monomer having an isocyanate group (a4) with a hydroxyl group-terminated prepolymer obtained by reacting the compound (a1) and the polyisocyanate (a2) at a ratio of 100 or less. The curable resin composition according to any one of claims 1 to 10.
A display device;
A transparent substrate disposed opposite to the viewing surface side of the display device;
A cured resin layer sandwiched between the display device and the transparent substrate;
A laminate having
The laminate is a cured resin layer obtained by curing the curable resin composition according to any one of claims 1 to 11.
An image display device having a cured resin layer formed by curing the curable resin composition according to any one of claims 1 to 11.