WO2019151509A1

WO2019151509A1 - Active energy ray-curable composition, and use thereof

Info

Publication number: WO2019151509A1
Application number: PCT/JP2019/003757
Authority: WO
Inventors: 明男荒野; 望月　克信
Original assignee: 東亞合成株式会社
Priority date: 2018-02-02
Filing date: 2019-02-01
Publication date: 2019-08-08
Also published as: JPWO2019151509A1

Abstract

[Problem] To provide an active energy ray-curable composition which exhibits excellent curability and also exhibits excellent adhesion between a cured product and a base material and excellent light transmission properties. [Solution] An active energy ray-curable composition which contains a vinyl polymer, a (meth)acryloyl group-containing compound, and a photopolymerization initiator, and which exhibits at least a certain curing speed even under relatively weak irradiation conditions of 5 mW/cm². The vinyl polymer may have 0.01-0.5 meq/g of double bonds in the molecule.

Description

Active energy ray-curable composition and use thereof

The present invention relates to an active energy ray-curable composition and a method for using a cured product formed from the composition.

A touch panel is widely used in a display device provided in a mobile communication device such as a mobile phone or a smart phone, and needs are diversified as the application expands. In the display device, in order to improve visibility and display characteristics, an active energy ray-curable resin composition is provided between an image display member such as a liquid crystal display panel or an organic EL panel and a light-transmitting optical member such as a touch panel or a protection panel. After applying an object, the optical adhesive layer is formed by irradiating and curing the active energy ray.
An active energy ray-curable composition containing a (meth) acrylate oligomer component, a (meth) acrylate monomer component, a photopolymerization initiator and a plasticizer is disclosed as an active energy ray-curable composition usable for such applications. (For example, Patent Document 1).

In recent years, display devices have been made thinner and larger screens, and in particular, in terms of in-vehicle applications, such as improved visibility, heat resistance due to a rise in vehicle temperature in summer, and irregular adhesion to curved display bodies Therefore, there is a demand for an optical adhesive layer having high light transmittance and excellent adhesion. In addition, there is a problem that the touch panel is deformed by curing shrinkage at the time of bonding. As a means to solve these problems, there is a method of increasing the plasticizer content in the composition. However, when a general plasticizer is used, the adhesive surface with the support is peeled off or moisture is removed in the heat and humidity resistance test. As a result, there is a problem in that the plasticizer hydrolyzes and precipitates decomposition products in the optical adhesive layer and the light transmittance is lowered.

On the other hand, as a means for improving the adhesion to the support, a composition containing an acrylic polymer has also been proposed. Patent Document 2 discloses an actinic radiation curable composition containing a polyfunctional (meth) acrylate, a polymerization initiator, and an acrylic polymer as a plasticizer. The acrylic polymer has a molecular weight of a so-called oligomer region. It is described that some hundreds to thousands are preferably used.

Generally, it is necessary to use a chain transfer agent when producing an acrylic polymer having a molecular weight of several hundred to several thousand. Patent Document 3 discloses a method using β-tert-butyl monoperoxyitaconate or the like as a chain transfer agent as a means for producing a low molecular weight acrylic polymer. However, when a low molecular weight plasticizer containing such a chain transfer agent is added to the active energy ray-curable composition, the chain transfer agent causes a curing delay during photocuring, or the compound derived from the chain transfer agent is photocured. There was a problem of bleeding out on the surface of the conductive resin composition. Patent Document 4 discloses a method for polymerizing a (meth) acryloyl group-containing monomer at a temperature of 180 ° C. to 350 ° C. as a method for efficiently producing a low molecular weight acrylic polymer without using a chain transfer agent. It is disclosed. However, since the acrylic polymer synthesized by such a method has a double bond at the molecular end, when blended in an active energy ray-curable composition as a plasticizer, the curability of the composition There is concern about this point.

As a means for solving the above-mentioned curable problem, the applicant has determined that the active energy ray-curable resin contains a polymer obtained by polymerizing a vinyl monomer at 150 to 350 ° C. and then adding hydrogen. A composition has been proposed (Patent Document 5).

JP-A-2016-199656 JP 2006-28405 A Japanese National Patent Publication No. 8-503988 International Publication No. 01/83619 International Publication No. 2014/167999

According to the method described in Patent Document 5, the amount of double bonds at the molecular terminals can be sufficiently reduced, and the curability of the composition during irradiation with active energy rays can be improved. There is a possibility that the metal catalyst used in the process is mixed into the acrylic polymer (plasticizer). When a plasticizer containing a metal catalyst is used for the production of a touch panel or the like, there is a concern that the metal catalyst leaks from the optical adhesive layer and can cause malfunction of the touch panel.

This invention is made | formed in view of the said situation, and it aims at providing the active energy ray curable composition which is excellent in sclerosis | hardenability, and is excellent also in adhesiveness with hardened | cured material and a base material, and light transmittance. And Another object of the present invention is to provide an optical adhesive layer formed from the above active energy ray-curable composition.

As a result of intensive studies, the inventors of the present invention are active energy ray-curable compositions containing a vinyl polymer, a (meth) acryloyl group-containing compound and a photopolymerization initiator, and exhibiting a specific curing rate. The knowledge which can solve the said subject was acquired. This invention is completed based on the said knowledge. According to the present specification, the following means are provided.

[1] An active energy ray-curable composition comprising a vinyl polymer (A), a (meth) acryloyl group-containing compound (B) and a photopolymerization initiator (C),
When the curable composition was applied to a film thickness of 15 μm and irradiated with light using a mercury xenon lamp as a light source under the condition of illuminance of 5 mW / cm ² with a UV-A wavelength, the following formula (1) An active energy ray-curable composition having a cure rate represented by 0.3% / second or more.
[Curing rate] (% / second) = (reaction rate of (meth) acryloyl group 20 seconds after light irradiation−reaction rate of (meth) acryloyl group 10 seconds after light irradiation) / light irradiation time (10 seconds) (1)
[2] The active energy ray-curable composition according to [1], wherein the curing rate is 0.3% to 10% / second.
[3] The active energy ray-curable composition according to [1] or [2], wherein the vinyl polymer (A) has a double bond in the molecule of 0.01 meq / g or more and 0.50 meq / g or less. .
[4] The vinyl polymer (A) includes (meth) acrylic acid ester having an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms in a structural monomer unit. [3] The active energy ray-curable composition according to any one of [3].
[5] The active energy ray-curable composition according to any one of [1] to [4], wherein the vinyl polymer (A) is obtained by a high-temperature continuous polymerization method under a polymerization temperature condition of 100 to 350 ° C. .
[6] The active energy ray-curable composition according to any one of [1] to [5], wherein the vinyl polymer (A) has a weight average molecular weight of 500 or more and 100,000 or less.
[7] The proportion of the vinyl polymer (A) and the (meth) acryloyl group-containing compound (B) used is (A) / (B) = 10 to 95/5 to 90 (mass ratio). [1] The active energy ray-curable composition according to any one of [6].
[8] The photopolymerization initiator (C) is contained in an amount of 0.5 to 5 parts by mass with respect to 100 parts by mass of the total amount of the vinyl polymer (A) and the (meth) acryloyl group-containing compound (B). [7] The active energy ray-curable composition according to any one of [7].
[9] An optical adhesive layer obtained by curing the active energy ray-curable composition according to any one of [1] to [8].

The active energy ray-curable composition of the present invention is excellent in curability. The obtained cured product is suitably used as an optical adhesive layer because it has excellent adhesion to a substrate and light transmittance.

Hereinafter, the present invention will be described in detail. In the present specification, “(meth) acryl” means acryl and / or methacryl, and “(meth) acrylate” means acrylate and / or methacrylate. The “(meth) acryloyl group” means an acryloyl group and / or a methacryloyl group.

The curable composition of the present invention comprises a vinyl polymer as component (A), a (meth) acryloyl group-containing compound as component (B), and a photopolymerization initiator as component (C). Below, the detail of each component is included and the curable composition and optical adhesive layer of this invention are demonstrated.

<(A) component: vinyl polymer>
A vinyl polymer is a polymer having a structural unit derived from a vinyl monomer, and can be obtained, for example, by polymerizing a monomer mixture containing a vinyl monomer. Examples of vinyl monomers are not particularly limited, and include (meth) acrylate and (meth) acrylic acid, aromatic monomers such as styrene and α-methylstyrene, and amide groups such as (meth) acrylamide. Examples include vinyl monomers, vinyl esters such as vinyl acetate, acrylonitrile, etc., but light transmittance, mechanical properties of cured products, flexibility, weather resistance, heat resistance, workability, adhesion, water resistance, etc. (Meth) acrylate is preferable because of its various performances.

Examples of (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t -Butyl (meth) acrylate, neopentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, nonyl (meth) acrylate, isononyl ( Linear such as (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate Or a (meth) acrylic acid alkyl ester having a branched aliphatic alkyl group or an alicyclic alkyl group; 2-methoxymethyl (meth) acrylate, 2-ethoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate 2-ethoxyethyl (meth) acrylate, 2-methoxybutyl (meth) acrylate, 2-ethoxybutyl (meth) acrylate, 2-butoxybutyl (meth) acrylate, 2-methoxyhexyl (meth) acrylate, 2-butoxyhexyl (Meth) acrylate, 2-methoxydecyl (meth) acrylate, 2-butoxydecyl (meth) acrylate, 2-methoxylauryl (meth) acrylate, 2-butoxylauryl (meth) acrylate, 2-methoxystearyl (meth) acrylate, -(Meth) acrylic acid alkoxyalkyl esters such as butoxycystearyl (meth) acrylate; heteroatom-containing (meth) acrylic esters such as dimethylaminoethyl (meth) acrylate and trifluoroethyl (meth) acrylate; 2-hydroxyethyl ( (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxy group-containing (meth) acrylic acid ester such as ε-caprolactone adduct of 2-hydroxyethyl (meth) acrylate; glycidyl ( Epoxy group-containing (meth) acrylic acid esters such as (meth) acrylate; 3-trimethoxysilylpropyl (meth) acrylate, 3-triethoxysilylpropyl (meth) acrylate, 3-triisopropoxysilyl Lopyl (meth) acrylate, 3-methyldimethoxysilylpropyl (meth) acrylate, 3-methyldiethoxysilylpropyl (meth) acrylate, 3-methyldiisopropoxysilylpropyl (meth) acrylate, 3-dimethylmethoxysilylpropyl (meth) ) Acrylate, 3-dimethylethoxysilylpropyl (meth) acrylate, 3-dimethylisopropoxysilylpropyl (meth) acrylate, alkoxysilyl group-containing (meth) acrylic acid ester such as 8-trimethoxysilyloctyl (meth) acrylate; benzyl (Meth) acrylate is mentioned.

Among these, (meth) acrylic acid esters having an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms are preferable from the viewpoint of flexibility. The alkyl group may have 1 to 12 carbon atoms or 4 to 12 carbon atoms. Further, the alkoxyalkyl group may have 2 to 12 carbon atoms or 4 to 12 carbon atoms.
The proportion of (meth) acrylic acid ester having an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms is 30% by mass or more based on the total monomers used for producing the vinyl polymer. It is preferably 50% by mass or more. The proportion of the (meth) acrylic acid ester having an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms may be 70% by mass or more, or 90% by mass or more, It may be 95% by mass or more, or 100% by mass.

The weight average molecular weight (Mw) of the vinyl polymer is a molecular weight in terms of polystyrene by gel permeation chromatography (hereinafter also referred to as “GPC”), preferably 500 or more, from the viewpoint of suppressing bleeding in the cured product. Preferably it is 1,000 or more, More preferably, it is 1,500 or more. The lower limit of Mw may be 3,000 or more, 5,000 or more, or 10,000 or more. On the other hand, from the viewpoint of coatability, the upper limit value of Mw is preferably 100,000 or less, more preferably 50,000 or less, and further preferably 40,000 or less. The upper limit value of Mw may be 30,000 or less, 20,000 or less, or 15,000 or less. The range of Mw can be set by combining the above upper limit value and lower limit value, and is, for example, 500 or more and 100,000 or less, and may be 1,000 or more and 50,000 or less. It may be 20,000 or less.

The molecular weight distribution of the vinyl polymer is calculated as a value (Mw / Mn) obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn). Mw / Mn is preferably 5.0 or less from the viewpoint of mechanical strength of the cured product, more preferably 4.0 or less, still more preferably 3.0 or less, and even more preferably 2.5 or less. And more preferably 2.0 or less. The lower limit value of Mw / Mn is usually 1.0.

The viscosity of the vinyl polymer is preferably 1,000 mPa · s or more at 25 ° C., more preferably 2,000 mPa · s or more. The viscosity may be 3,000 mPa · s or more, 5,000 mPa · s or more, or 10,000 mPa · s or more. The upper limit of the viscosity is preferably 100,000 mPa · s or less, more preferably 80,000 mPa · s or less, and still more preferably 60,000 mPa · s or less. The upper limit of the viscosity may be 40,000 mPa · s or less, 30,000 mPa · s or less, or 20,000 mPa · s or less. If the viscosity is 1,000 mPa · s or more, the fluidity of the curable composition is suppressed, and this is preferable because it is easy to be cured in a desired form and shape. The workability of the composition is improved. The viscosity range can be set by combining the above upper limit value and lower limit value. For example, the viscosity range is 1,000 mPa · s or more and 100,000 mPa · s or less, and 2,000 mPa · s or more and 80,000 mPa · s. Or 3,000 mPa · s or more and 60,000 mPa · s or less.

In the present invention, the vinyl polymer may have a double bond in the molecule. When the vinyl polymer has an appropriate amount of double bonds, the vinyl polymer is copolymerized with a matrix formed by polymerizing a (meth) acryloyl group-containing compound which is a component (B) described later, It is taken in moderately. For this reason, the compatibility of a vinyl polymer and the said matrix improves, and the hardened layer excellent in light transmittance can be obtained. In addition, the said mechanism is inference and does not limit the scope of the present invention.

The amount of double bonds contained in the vinyl polymer is preferably 0.01 meq / g or more from the viewpoint of obtaining a cured product having good light transmittance. The amount of double bonds may be 0.03 meq / g or more, 0.05 meq / g or more, 0.10 meq / g or more, or 0.20 meq / g or more. May be. On the other hand, from the viewpoint of curability, the upper limit of the double bond amount is preferably 1.0 meq / g or less, and more preferably 0.50 meq / g or less. The upper limit of the double bond amount may be 0.40 meq / g or less, or 0.30 meq / g or less. The range of the amount of double bonds can be set by combining the above upper limit value and lower limit value. For example, it is 0.01 meq / g or more and 1.0 meq / g or less, and 0.01 meq / g or more and 0 or less. .50 meq / g or less, or 0.05 meq / g or more and 0.50 meq / g or less. In the present invention, the double bond amount means a value calculated from ¹ H-NMR of the polymer.

There is no particular limitation on the method for introducing a double bond, and methods known to those skilled in the art can be employed. For example, a method of copolymerizing a monomer having a plurality of double bonds in the molecule, a compound having a functional group capable of reacting with the functional group and a compound having a double bond after producing a vinyl polymer having a functional group Examples include a method of reacting.

Also, a double bond can be introduced by producing a vinyl polymer under high temperature conditions. For example, when a monomer having an acryloyl group is polymerized at a polymerization temperature of 100 ° C. or higher, a cleavage reaction starting from a hydrogen abstraction reaction from a polymer chain occurs due to high temperature polymerization. The polymer which has an ethylenically unsaturated bond represented by this is obtained. The polymerization temperature is preferably 120 ° C. or higher, more preferably 150 ° C. or higher. As the polymerization temperature increases, the double bond concentration in the polymer also tends to increase. According to the said method, the vinyl polymer which has a double bond simply and with sufficient productivity can be obtained. Furthermore, it is possible to easily produce the molecular weight control without containing a large amount of impurities such as an initiator and a chain transfer agent. It is preferable not to use a chain transfer agent such as mercaptan because it leads to a decrease in weather resistance. On the other hand, the upper limit of the polymerization temperature is preferably 350 ° C. or less from the viewpoint that there is no possibility of coloring of the polymerization solution or molecular weight reduction due to the decomposition reaction. By polymerizing in the above temperature range, it is possible to efficiently produce a copolymer having an appropriate molecular weight, low viscosity, no coloration and little impurities. That is, according to the polymerization method, a very small amount of polymerization initiator may be used, and it is not necessary to use a chain transfer agent such as mercaptan or a polymerization solvent, and a highly pure copolymer can be obtained. .

R ¹ in the general formula (1) is an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an alkyl group which may have other substituents, a phenyl group, a benzyl group, a polyalkylene glycol group, a dialkylamino group. An alkyl group, a trialkoxysilylalkyl group, an alkyldialkoxysilylalkyl group, or a hydrogen atom.

The vinyl polymer can be produced by ordinary radical polymerization. Any of solution polymerization, bulk polymerization, and dispersion polymerization may be employed, and a living radical polymerization method may be used. The reaction process may be any of batch, semi-batch and continuous polymerization. Among these, a high temperature continuous polymerization method under a polymerization temperature condition of 100 to 350 ° C. or 150 to 350 ° C. is preferable.

As the high temperature continuous polymerization method, a known method disclosed in JP-A-57-502171, JP-A-59-6207, JP-A-60-215007, or the like may be used. For example, after filling a pressurizable reactor with a solvent and setting it to a predetermined temperature under pressure, the reactor is charged with a monomer mixture comprising each monomer and, if necessary, a polymerization solvent at a constant supply rate. And a method of extracting a polymerization solution in an amount commensurate with the supply amount of the monomer mixture. Moreover, a polymerization initiator can also be mix | blended with a monomer mixture as needed. The blending amount when blended is preferably 0.001 to 2 parts by mass with respect to 100 parts by mass of the monomer mixture. The pressure depends on the reaction temperature, the monomer mixture used and the boiling point of the solvent, and does not affect the reaction, but may be any pressure that can maintain the reaction temperature. The residence time of the monomer mixture is preferably 1 to 60 minutes. If the residence time is less than 1 minute, the monomer may not react sufficiently, and if the unreacted monomer exceeds 60 minutes, the productivity may deteriorate. The preferred residence time is 2 to 40 minutes.

As an example of the polymerization initiator used for obtaining the vinyl polymer, any initiator that generates radicals at a predetermined reaction temperature may be used. Specifically, di-t-butyl peroxide, di-t-hexyl peroxide, t-hexyl peroxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, cumene hydroper Organic peroxides such as oxide and t-butyl hydroperoxide, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2-methylbutyronitrile), azobiscyclohexacarbonitrile, Examples thereof include azo compounds such as azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-amidinopropane) dihydrochloride, 4,4′-azobis (4-cyanovaleric acid). One of these polymerization initiators may be used alone, or two or more thereof may be used in combination. When a polymerization initiator having a high hydrogen abstraction ability is used, the double bond concentration of the resulting polymer tends to increase. For example, when an organic peroxide is used rather than an azo compound, a polymer having a high double bond concentration tends to be obtained.
The amount of the polymerization initiator used can be appropriately adjusted depending on the kind of the polymerization initiator and the monomer, the desired molecular weight, the polymerization conditions, etc., but in general, with respect to 100 parts by mass of the monomer used. 0.001 to 10 parts by mass. When obtaining a polymer having the same molecular weight, the smaller the amount of polymerization initiator used, the higher the double bond concentration in the resulting polymer.

When an organic solvent is used for producing the vinyl polymer, organic hydrocarbon compounds are suitable, cyclic ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbon compounds such as benzene, toluene and xylene, ethyl acetate and butyl acetate, etc. Examples of such esters, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and alcohols such as methanol, ethanol, and isopropanol are exemplified, and one or more of these can be used. In a solvent that does not dissolve the (meth) acrylic acid ester copolymer well, scales are likely to grow on the walls of the reactor, and production problems are likely to occur in the cleaning process. In addition, when an organic solvent having a high chain transfer ability such as isopropanol is used, the double bond concentration in the resulting polymer tends to be low.
It is preferable that the usage-amount of a solvent shall be 80 mass parts or less with respect to 100 mass parts of all vinyl monomers. By setting it to 80 parts by mass or less, a high conversion rate can be obtained in a short time. More preferably, it is 1 to 50 parts by mass. A dehydrating agent such as trimethyl orthoacetate or trimethyl orthoformate can also be added.

A known chain transfer agent may be used for the production of the vinyl polymer. When a chain transfer agent is used, the double bond concentration in the resulting polymer tends to be low. In general, the double bond concentration is lowered by increasing the amount of the chain transfer agent used.

The reaction solution withdrawn from the reactor proceeds to the next step as it is, or the polymer is simply removed by distilling off volatile components such as unreacted monomers, solvents and low molecular weight oligomers by distillation or the like. Can be separated. A part of volatile components such as unreacted monomers, solvent, and low molecular weight oligomers distilled off from the reaction solution can be returned to the raw material tank or directly returned to the reactor and used again for the polymerization reaction.
Thus, the method of recycling an unreacted monomer and a solvent is a preferable method from an economical viewpoint. In the case of recycling, it is necessary to determine the mixing ratio of the newly supplied monomer mixture so as to maintain the desired monomer ratio and the desired amount of solvent in the reactor.

The amount of double bonds introduced into the polymer can be reduced by adding a radical generator and post-treating under heating conditions. As the radical generator, a known compound capable of generating radicals can be used. Specific examples of the radical generator include the polymerization initiator used to obtain the vinyl polymer described above. The addition amount of the radical generator is about 0.1 to 10 parts by mass with respect to 100 parts by mass of the polymer. The larger the addition amount, the greater the effect of reducing the double bond concentration.
The heating temperature during the heat treatment is about 50 to 130 ° C., but the lower the temperature, the greater the effect of reducing the double bond concentration. The heating temperature is preferably in the range of 50 to 110 ° C, more preferably in the range of 50 to 100 ° C.
The heat treatment time is not particularly limited, but is preferably set so that the amount of the remaining radical generator is less than 1% by mass with respect to the polymer. A person skilled in the art can calculate the remaining radical from the activation energy, frequency factor and reaction temperature of the radical generator used.

The double bond concentration can also be reduced by hydrogenating the vinyl polymer as a post treatment. For hydrogenation, a conventionally known method can be employed.
That is, after adding a homogeneous catalyst or a heterogeneous catalyst to the polymer reaction solution, the inside of the system is made a hydrogen atmosphere, the pressure is heated to normal pressure to 10 MPa, the temperature is heated to about 20 to 180 ° C., and about 2 to 20 hours. React. Specific examples of homogeneous catalysts include rhodium complexes such as chlorotris (triphenylphosphine) rhodium, ruthenium complexes such as dichlorotris (triphenylphosphine) ruthenium, chlorohydrocarbonyltris (triphenylphosphine) ruthenium, dichlorobis (triphenylphosphine) ) Platinum complexes such as platinum, and iridium complexes such as carbonylbis (triphenylphosphine) iridium. On the other hand, examples of the heterogeneous catalyst include solid catalysts in which transition metals such as nickel, rhodium, ruthenium, palladium, and platinum are supported on carbon, silica, alumina, fibers, organic gels, and the like. The heterogeneous catalyst is preferable in that the catalyst can be easily removed by filtration or the like, so that the quality is stable and an expensive catalyst can be reused. The amount of catalyst to be added is about 10 to 1,000 ppm with respect to the vinyl polymer in the case of a homogeneous catalyst. In the case of a heterogeneous catalyst, it is about 1,000 to 10,000 ppm.

<(B) component: (meth) acryloyl group-containing compound>
The component (B) in the present invention is a compound having a (meth) acryloyl group in the molecule.
Examples of the (meth) acryloyl group-containing compound include (meth) acrylic acid and (meth) acrylate, and among these, (meth) acrylate is preferable. As (meth) acrylate, a compound having one (meth) acryloyl group in the molecule [hereinafter referred to as “monofunctional (meth) acrylate”] and a compound having two or more (meth) acryloyl groups in the molecule [Hereinafter referred to as “polyfunctional (meth) acrylate”].

Monofunctional (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, and stearyl ( Alkyl (meth) acrylates such as meth) acrylate; cyclohexyl (meth) acrylate, tricyclodecane (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) Alicyclic (meth) acrylates such as acrylate, dicyclopentanyloxyethyl (meth) acrylate, isobornyl (meth) acrylate and adamantyl (meth) acrylate; 2-hydroxy Hydroxyl group-containing (meth) acrylates such as chill (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate; 2-methoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, Alkoxyalkyl (meth) acrylates such as 2-ethylhexyl carbitol (meth) acrylate and ethoxyethoxyethyl (meth) acrylate; phenoxyethyl (meth) acrylate, o-phenylphenoxyethyl (meth) acrylate, p-cumylphenoxyethyl ( (Meth) acrylates, nonylphenoxyethyl (meth) acrylates, benzyl (meth) acrylates, (meth) acrylates of phenol derivatives modified with alkylene oxide and 2-hydroxy Aromatic (meth) acrylates such as cis-3-phenoxypropyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate; N- (meth) acryloyloxyethyl tetrahydrophthalimide and N- (meth) acryloyloxyethyl hexahydrophthalimide Maleimide (meth) acrylate; glycidyl (meth) acrylate, polycaprolactone modified product of (meth) acrylic acid, polycaprolactone modified product of 2-hydroxyethyl (meth) acrylate, 3- (trimethoxysilyl) propyl (meth) acrylate 3- (triethoxysilyl) propyl (meth) acrylate, 3- (methyldimethoxysilyl) propyl (meth) acrylate, 3- (methyldiethoxysilyl) propyl (meth) acrylate and No doubt imidazolidinone ethyl (meth) acrylate.

Examples of the polyfunctional (meth) acrylate include 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonanediol. Di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, 3-methyl-1 , 5-pentanediol di (meth) acrylate, 2-butyl-2-ethyl-1,3-nonanediol diacrylate, 2-methyl-1,8-octanediol di (meth) acrylate, 2-hydroxy-1, 3-di (meth) acrylo Ruoxypropane, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) ) Polyacrylates such as acrylates, dipentaerythritol penta (meth) acrylates, dipentaerythritol hexa (meth) acrylates, ditrimethylolpropane tetra (meth) acrylates; alkylene oxides of these poly (meth) acrylates [Ethylene oxide, propylene oxide, etc.] Adduct poly (meth) acrylate; Capro of the raw alcohol of these poly (meth) acrylates Poly (meth) acrylates of kuton-modified products; poly (meth) acrylates of alkylene oxide-modified isocyanuric acid such as di (meth) acrylate of ethylene oxide-modified isocyanuric acid and tri (meth) acrylate of ethylene oxide-modified isocyanuric acid However, it is not limited to these.
As polyfunctional (meth) acrylate, an oligomer can also be used, and specifically, urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate and the like can be mentioned.

In addition to the above, as an example of the polyfunctional (meth) acrylate, a glycidyl group of a vinyl polymer obtained by polymerizing a vinyl monomer having a glycidyl group alone or with a copolymerizable vinyl monomer In addition, a vinyl polymer having a (meth) acrylate group in the side chain obtained by reacting a (meth) acrylate having a carboxyl group is also mentioned.
These monofunctional or polyfunctional (meth) acrylates may be used alone or in combination of two or more.

As the (meth) acryloyl group-containing compound, a polyfunctional (meth) acrylate is preferable in that an adhesive layer showing good strength can be obtained. The polyfunctional (meth) acrylate is preferably contained in an amount of 20 to 100% by mass based on the total amount of the (meth) acryloyl group-containing compound. The proportion of the polyfunctional (meth) acrylate may be 50 to 100% by mass, 80 to 100% by mass, or 100% by mass.

<(C) component: photopolymerization initiator>
This composition contains a photopolymerization initiator as the component (C) for the purpose of curing with active energy rays such as ultraviolet rays and visible light.
Photopolymerization initiators include benzyl dimethyl ketal, benzyl, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 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, oligo [2-hydroxy-2-methyl-1- [4-1- (methyl Vinyl) phenyl] propanone, 2-hydroxy-1- [4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl] -2-methylpropan-1-one, 2-methyl-1 -[4- (methylthio)] phenyl] -2-morpholinopropan-1-one, 2 Benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) -butane Aromatic ketone compounds such as 1-one, Adekaoptomer N-1414 (manufactured by ADEKA Corporation), phenylglyoxylic acid methyl ester, ethyl anthraquinone, phenanthrenequinone, and the like;
Benzophenone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone, 4- (methylphenylthio) phenylphenylmethane, methyl-2-benzophenone, 1- [4- (4-Benzoylphenylsulfanyl) phenyl] -2-methyl-2- (4-methylphenylsulfonyl) propan-1-one, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis ( Benzophenone compounds such as diethylamino) benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone, N, N′-tetraethyl-4,4′-diaminobenzophenone and 4-methoxy-4′-dimethylaminobenzophenone ;
Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl- (2,4,6-trimethylbenzoyl) phenylphosphinate and bis (2, Acylphosphine oxide compounds such as 6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide;
Thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propylthioxanthone, 3- [3,4-dimethyl-9-oxo-9H-thioxanthone-2-yl] oxy]- Thioxanthone compounds such as 2-hydroxypropyl-N, N, N-trimethylammonium chloride and fluorothioxanthone;
Acridone compounds such as acridone, 10-butyl-2-chloroacridone;
1,2-octanedione 1- [4- (phenylthio) -2- (O-benzoyloxime)] and ethanone 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] Oxime esters such as -1- (O-acetyloxime);
2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-phenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2 2,4,5-triarylimidazole such as 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer and 2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole dimer Dimer; and acridine derivatives such as 9-phenylacridine and 1,7-bis (9,9'-acridinyl) heptane.
These compounds may be used alone or in combination of two or more.

<Active energy ray-curable composition>
The active energy ray-curable composition of the present invention contains the component (A) to the component (C). The ratio of the component (A) and the component (B) in the curable composition is preferably (A) / (B) = 10 to 95/5 to 90 in terms of mass ratio. If the ratio of (A) component and (B) component is said range, while being excellent in sclerosis | hardenability, the photocuring contact bonding layer which is excellent also in adhesiveness with a base material and light transmittance can be obtained. The above (A) / (B) is more preferably 10-80 / 20-90.

The blending ratio of the photopolymerization initiator (component (C)) in the curable composition of the present invention is 0.01 to 10 mass with respect to 100 mass parts of the total amount of the components (A) and (B). It is preferable to be in the range of parts. By setting the blending ratio of the photopolymerization initiator to 0.01 parts by mass or more, the composition can be cured with an appropriate amount of ultraviolet light or visible light, and the productivity can be improved. By doing, it can be excellent in the weather resistance and transparency of the cured product. The blending ratio of the photopolymerization initiator is more preferably in the range of 0.1 to 10 parts by mass, and still more preferably in the range of 0.5 to 5 parts by mass.

The active energy ray-curable composition of the present invention is irradiated with light under conditions of an illuminance of 5 mW / cm ^{2 at} a UV-A wavelength using a mercury xenon lamp as a light source, coating the curable composition to a film thickness of 15 μm. When performing, it is preferable that the hardening rate represented by the following formula | equation (1) is 0.3% / second or more. The curing rate is preferably 0.5% / second or more, more preferably 1.0% / second or more, from the viewpoint of light transmittance of the cured product and adhesion to the substrate. The curing rate may be 2.0% / second or more, or 3.0% / second or more. The accuracy of the film thickness is preferably 15.0 ± 1.0 μm, more preferably 15.0 ± 0.5 μm. The illuminance is based on the wavelength in the UV-A region, and can be measured using a commercially available illuminometer. More specifically, it can be measured by the method described in Examples described later.
[Curing rate] (% / second) = (reaction rate of (meth) acryloyl group 20 seconds after light irradiation−reaction rate of (meth) acryloyl group 10 seconds after light irradiation) / light irradiation time (10 seconds) (1)

The reaction rate of the (meth) acryloyl group is the absorption peak height (X) of the (meth) acryloyl group in the FT-IR measurement chart of the active energy ray-curable composition before light irradiation (before the active energy ray irradiation), and From the absorption peak height (Y) of the (meth) acryloyl group in the FT-IR measurement chart of the active energy ray-curable composition after light irradiation (after active energy ray irradiation), it is calculated by the following formula (2).
[Reaction rate of (meth) acryloyl group] (%) = {(XY) / X} × 100 (2)

As described above, the curing rate of the present invention is calculated from the reaction rate of (meth) acryloyl groups from 10 seconds to 20 seconds after light irradiation. Here, immediately after the light irradiation, curing inhibition due to the influence of dissolved oxygen contained in the active energy ray-curable composition is observed. For this reason, immediately after the light irradiation, the radical reaction of the (meth) acryloyl group may not start normally, and is not appropriate as a measurement start point for the curing rate. On the other hand, the end point of the measurement of the curing rate is preferably set before the radical reaction reaches a convergence tendency. From such a viewpoint, the curing rate is calculated using the reaction rate of the (meth) acryloyl group from 10 seconds to 20 seconds after light irradiation.
Those skilled in the art based on the disclosure of the present specification, the double bond concentration contained in the vinyl polymer (A), the type and concentration of the (meth) acryloyl group-containing compound (B), the photopolymerization initiator (C ), The curing rate of the curable composition can be adjusted to the above range.

The active energy ray-curable composition of the present invention is a composition containing the component (A) to the component (C), and has a certain curing rate even under relatively weak irradiation conditions of 5 mW / cm ^2. It is shown. A cured product (cured layer) obtained from the curable composition exhibiting such a curing rate is excellent in light transmittance and adhesiveness to the substrate.

<Other ingredients>
The active energy ray-curable composition of the present invention essentially comprises the above-described component (A), component (B) and component (C), but may contain other components as necessary. . Hereinafter, other components that can be blended will be described.
(1) Solvent (solvent)
The composition of the present invention may be a solvent-free system that does not contain a solvent, or may contain a solvent such as an organic solvent for the purpose of improving coating properties. As an organic solvent, the organic solvent which can be used for manufacture of the vinyl polymer which is (A) component can be used, for example.
The proportion of the solvent used may be set as appropriate, but is preferably 10 to 90% by mass, more preferably 30 to 80% by mass in the composition. When a composition contains a solvent, after applying the composition, the solvent may be volatilized and removed by heating or the like and then irradiated with active energy rays to obtain a cured product.

(2) Other ethylenically unsaturated monomers As long as the effects exhibited by the present invention are not impaired, other ethylenically unsaturated monomers are used as monomers other than the component (B) in the curable composition. Ingredients may be included. Other ethylenically unsaturated monomers include
Aromatic monomers such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and salts thereof;
Maleic anhydride; unsaturated dicarboxylic acids such as maleic acid and fumaric acid, and their monoalkyl and dialkyl esters;
Maleimide compounds such as maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, phenylmaleimide, cyclohexylmaleimide;
Nitrile group-containing vinyl monomers such as acrylonitrile and methacrylonitrile;
Amide group-containing vinyl monomers such as acrylamide and methacrylamide;
Vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate;
Alkenes such as ethylene and propylene;
Conjugated dienes such as butadiene and isoprene;
Examples include, but are not limited to, vinyl chloride, vinylidene chloride, allyl chloride, and allyl alcohol. Moreover, 1 type, or 2 or more types of these can be used.

(3) Other components In addition to the above, the composition of the present invention includes a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, a leveling agent, an antifoaming agent, a surface conditioner, an adhesion promoter, a rheology. Control agents, waxes, inorganic fillers, organic fillers, moisture curing catalysts, and the like can be added.

As the polymerization inhibitor, hydroquinone, hydroquinone monomethyl ether, 2,6-di-tert-butyl-4-methylphenol, and various phenolic antioxidants are preferable, but sulfur secondary antioxidants, phosphorus secondary antioxidants are preferable. A secondary antioxidant or the like can also be added.

Examples of ultraviolet absorbers include 2- (2′-hydroxy-5-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2- (2 Benzotriazole compounds such as'-hydroxy-3'-t-butyl-5'-methylphenyl)benzotriazole;
Triazine compounds such as 2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-iso-octyloxyphenyl) -s-triazine;
2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2, 4, 4 ' -Trihydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3', 4,4'-tetrahydroxybenzophenone, or 2,2 Examples include benzophenone compounds such as'-dihydroxy-4,4'-dimethoxybenzophenone.

Examples of the light stabilizer include N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) -N, N′-diformylhexamethylenediamine, bis (1,2,6,6). -) Pentamethyl-4-piperidyl) -2- (3,5-ditertiarybutyl-4-hydroxybenzyl) -2-n-butylmalonate, bis (1,2,2,6,6-pentamethyl-4- Low molecular weight hindered amine compounds such as piperidinyl) sebacate; N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) -N, N′-diformylhexamethylenediamine, bis (1,2 Hindered amine light stabilizers such as high molecular weight hindered amine compounds such as 2,6,6-pentamethyl-4-piperidinyl) sebacate.

The composition of the present invention can be obtained by mixing the above-mentioned raw materials at room temperature or under heating by a conventionally known method. The viscosity of the composition is not particularly limited, but it is preferably 200 to 20,000 mPas at 25 ° C. When the viscosity is within this range, smooth coating is possible.

<Use of active energy ray-curable composition>
The cured product (cured layer) obtained from the active energy ray-curable composition of the present invention exhibits excellent light transmittance and excellent adhesion to the substrate. For this reason, the application to the bonding use of an optical member is possible, for example. As a base material which comprises an optical member, transparent plastics, such as a polycarbonate, a polymethylmethacrylate, a cycloolefin polymer (COP), glass, etc. are mentioned, for example, Among these, 1 type (s) or 2 or more types are used.
The said hardened | cured material (hardened layer) can be used as an adhesive layer for optics in various displays, such as bonding of the member which comprises a touchscreen, and a liquid crystal display, EL display, and a plasma display.

After applying the active energy ray-curable composition to the substrate, the optical adhesive layer is bonded to another substrate, and the active energy ray is irradiated from the transparent substrate side to apply the curable composition. It can be obtained by curing.

What is necessary is just to follow a conventional method as a coating method of a curable composition.
Specific examples include bar coating, roll coating, spin coating, dip coating, gravure coating, flow coating, and spray coating. As needed, you may pass through the drying process or preheating process for evaporating a solvent after application | coating and before irradiating an active energy ray.
The drying temperature or preheating temperature is not particularly limited as long as the applied substrate is at a temperature that does not cause problems such as deformation.

Examples of the active energy rays for curing the curable composition after coating include electron beams, ultraviolet rays, visible rays, and X-rays, but ultraviolet rays are preferable because inexpensive devices can be used.
Examples of the ultraviolet irradiation device include a high-pressure mercury lamp, a mercury xenon lamp, a metal halide lamp, a UV electrodeless lamp, and an LED.
The irradiation energy should be appropriately set according to the type and composition of the active energy ray. As an example, when using a high-pressure mercury lamp, the irradiation energy in the UV-A region is 100 to 5,000 mJ / cm ² is preferable, and 200 to 5,000 mJ / cm ² is more preferable.

The film thickness of the optical adhesive layer may be appropriately set according to the purpose, but is about 5 to 400 μm.

Hereinafter, the present invention will be specifically described based on examples. In addition, this invention is not limited by these Examples. In the following, “parts” and “%” mean mass parts and mass% unless otherwise specified.
It describes below about the analysis method of the polymer obtained by the manufacture example, the Example, and the comparative example, and the evaluation method of the hardened | cured material obtained from the curable composition.

<Quantification method of double bond amount>
It can be quantified as follows by measurement of ¹ H-NMR.
Double bond amount (meq / g) = (value obtained by integrating ¹ H-NMR integrated value of hydrogen atom derived from polymer observed at 5.2 to 5.7 ppm) × ((each vinyl monomer The total number of protons of each vinyl monomer observed at 3.0 to 4.5 ppm) / ((100 × ( ¹ H-NMR integral observed at 3.0 to 4.5 ppm)) Value) × 1000, where the total number of each vinyl monomer is 100 parts, the number of moles of each vinyl monomer = the number of parts of each vinyl monomer / the molecular weight of each vinyl monomer.

<Molecular weight measurement>
Using a gel permeation chromatograph (model name “HLC-8320”, manufactured by Tosoh Corporation), a number average molecular weight (Mn) and a weight average molecular weight (Mw) in terms of polystyrene were obtained from the following conditions. Moreover, molecular weight distribution (Mw / Mn) was computed from the obtained value.
○ Measurement condition column: Tosoh TSKgel SuperMultipore HZ-M × 4 Column temperature: 40 ° C.
Eluent: Tetrahydrofuran Detector: RI

<Viscosity of vinyl polymer>
Using a TVE-20H viscometer (salt water / flat plate method, manufactured by Toki Sangyo Co., Ltd.), the E type viscosity was measured under the following conditions.
○ Measurement conditions Cone shape: angle 1 ° 34 ', radius 24mm (less than 10000mPa · s)
Angle 3 °, radius 7.7mm (10000mPa · s or more)
Temperature: 25 ° C ± 0.5 ° C

<Curing rate of curable composition>
(1) Measurement of curing rate A solution of an active energy ray-curable composition was dropped on a ZEONOR (100 μm-thick cycloolefin polymer) film made by Nippon Zeon on which a copper foil separator having a thickness of 15 μm was placed. Covered with a ZEONOR film (100 μm thick) to obtain a laminate having a 15 μm thick layer of the curable composition. An FT-IR measurement device (manufactured by Nicolet Corp., model) while irradiating UV light with an illuminance of 5 mW / cm ^{2 at} a UV-A wavelength using a UV irradiation device (LIGHTNINGCURE LC5) manufactured by Hamamatsu Photonics using a mercury xenon lamp as a light source. The cure rate was measured by measuring in real time the unsaturated double bond of the (meth) acryloyl group with iS50FT-IR). The peak at 1640 to 1610 cm-1 as the unsaturated double bond peak of the (meth) acryloyl group, or the peak at 820 to 800 cm-1 when the absorption peak of the adjacent carbonyl group is strong and the change in absorbance is difficult to observe Was used for analysis.
The reaction rate of the (meth) acryloyl group is the absorption peak height (X) of the (meth) acryloyl group in the FT-IR measurement chart of the curable composition before ultraviolet irradiation, and the photocurable composition after ultraviolet irradiation. It was calculated by the following formula (4) from the absorption peak height (Y) of the (meth) acryloyl group in the FT-IR measurement chart.
[Reaction rate of (meth) acryloyl group] (%) = {(XY) / X} × 100 (4)
Moreover, the cure rate was calculated | required by the following formula | equation (5) from the reaction rate of the said (meth) acryloyl group.
[Curing rate] (% / second) = (reaction rate of (meth) acryloyl group 20 seconds after light irradiation−reaction rate of (meth) acryloyl group 10 seconds after light irradiation) / light irradiation time (10 seconds) (5)

<Light transmission>
Using an applicator, the active energy ray-curable composition is applied to a lightly peeled PET film (film binder 75E-0010HTA, manufactured by Fujimori Kogyo Co., Ltd.) having a width of 300 mm, a length of 400 mm, and a thickness of 50 μm. Was applied to a thickness of 250 μm. Subsequently, a heavy release PET film (Fujimori Kogyo Co., Ltd., film binder KF-50) having a width of 300 mm, a length of 400 mm, and a thickness of 50 μm was bonded.
Using an ultraviolet ray irradiation device (US-5X0602) manufactured by Eye Graphics Co., Ltd., which uses a high-pressure mercury lamp (80 W / cm, ozone-less) as a light source, UV-A wavelength illuminance of 120 mW / cm ² is applied and the integrated light intensity is 3000 mJ / cm ^2. After irradiating through a PET film so that it becomes, the sample sheet of 25 mm x 70 mm was cut out. After peeling off the lightly peeled PET film from the sample sheet and pasting it onto a white slide glass (S-1112 manufactured by Matsunami Glass Industry Co., Ltd.), the heavy peeled PET film (film binder 75E-0010HTA) is peeled off and pasted onto the white slide glass. In addition, a cured product for light transmittance measurement was produced. Using a haze meter (NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.), the initial total light transmittance and the total light transmittance after a 1000 hour wet heat test in an 85 ° C., 85% RH environment were measured. The light transmittance was judged according to the criteria of
Initial ○: Total light transmittance is 99% or more ×: Total light transmittance is less than 99%
After wet heat test ○: Total light transmittance is 87% or more ×: Total light transmittance is less than 87%

<Adhesion>
A cured product for measurement was prepared in the same manner as the cured product for light transmission measurement, and left for 1000 hours in an environment of 85 ° C. and 85% RH, and peeling was confirmed visually.
○: Area ratio of peeling in the deposition area is less than 1% Δ: Area ratio of peeling in the deposition area is 1% or more and less than 10% ×: Area ratio of peeling in the deposition area is 10% or more

<Compatibility after irradiation with active energy rays>
Two white slide glasses having a thickness of 1 mm were bonded so that the film thickness obtained from the curable composition was 100 μm. Ultraviolet rays having an illuminance of 92 mW / cm ^{2 with} a UV-A wavelength are applied to the curable composition sandwiched between white slide glasses by an ultraviolet ray irradiation apparatus (UBX01.51-3L1) manufactured by Igraphics using a high-pressure mercury lamp as a light source. Was irradiated and cured through glass so that the integrated light amount was 3000 mJ / cm ^2, and the compatibility state of the formed adhesive layer was visually confirmed.
○: Haze value is less than 0.1% Δ: Haze value is 0.1% or more and less than 0.2% ×: Haze value is 0.2% or more

<< (A) component: Production of vinyl polymer >>
Production Example 1 (Production of vinyl polymer A-1)
Polymerization process The jacket temperature of a pressurized stirring tank reactor having a capacity of 1,000 mL equipped with an oil jacket was kept at 248 ° C. Next, while maintaining the reactor pressure constant, 100 parts of 2-ethylhexyl acrylate (hereinafter referred to as “HA”) as a monomer, 20 parts of isopropyl alcohol and 20 parts of methyl ethyl ketone as polymerization solvents were polymerized. As an initiator, a monomer mixture consisting of 2.0 parts of di-tert-butyl peroxide (manufactured by NOF Corporation, trade name “Perbutyl D”, hereinafter referred to as “DTBP”) is supplied at a constant feed rate (48 g / Minutes and residence time: 12 minutes), continuous supply from the raw material tank to the reactor was started, and a reaction liquid corresponding to the supply amount of the monomer mixture was continuously withdrawn from the outlet. Immediately after the start of the reaction, once the reaction temperature decreased, a temperature increase due to the heat of polymerization was observed. However, the internal temperature of the reactor was maintained at 241 to 243 ° C. by controlling the oil jacket temperature. The time point after 36 minutes from the stabilization of the reactor internal temperature was taken as the reaction liquid collection start point, and the reaction was continued for 25 minutes thereafter. In this production, as a result, 1.2 kg of the monomer mixture was supplied and 1.2 kg of the reaction liquid was recovered. Thereafter, the reaction solution was introduced into a thin film evaporator, and volatile components such as unreacted monomers were separated and removed to obtain a polymer. As a result of GPC measurement of the polymer, the number average molecular weight (hereinafter referred to as “Mn”) is 1,200, the weight average molecular weight (hereinafter referred to as “Mw”) is 1,600, and the viscosity is 430 mPa · s. Met. The double bond concentration determined from ¹ H-NMR measurement was 0.22 meq / g.

○ Post-treatment step 1000 g of the polymer was charged into a 2000 mL stirred tank reactor equipped with an oil jacket, and the atmosphere in the reactor was purged with nitrogen while flowing 100 mL / min of nitrogen. Thereafter, the internal temperature was raised to 90 ° C., and 36 g of t-hexylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name “Perhexyl O”) was added and stirred in this state for 16 hours. A radical addition reaction was performed to obtain vinyl polymer A-1. As a result of GPC measurement of the vinyl polymer A-1, Mn was 1,400, Mw was 2,300, and the viscosity was 650 mPa · s. The double bond concentration determined by ¹ H-NMR measurement was 0.02 meq / g.

Production Example 2 (Production of vinyl polymer A-2)
A polymer was obtained by performing the same operation as in the polymerization step of Synthesis Example 1 except that the raw materials used and the reactor internal / external temperature were changed as shown in Table 1. As a result of GPC measurement of the polymer, Mn was 2,700, Mw was 4,700, and the viscosity was 2,900 mPa · s. The double bond concentration determined by ¹ H-NMR measurement was 0.22 meq / g.
Thereafter, the same operation as in the post-treatment step of Synthesis Example 1 was performed on the above polymer to obtain a vinyl polymer A-2. The properties of the vinyl polymer A-2 are shown in Table 1.

Production Example 3 (Production of vinyl polymer A-3)
A polymer was obtained by performing the same operation as in the polymerization step of Synthesis Example 1 except that the raw materials used and the reactor internal / external temperature were changed as shown in Table 1. As a result of GPC measurement of the polymer, Mn was 2,200, Mw was 3,600, and the viscosity was 1,570 mPa · s. The double bond concentration determined by ¹ H-NMR measurement was 0.30 meq / g.
Thereafter, the same operation as in the post-treatment step of Synthesis Example 1 was performed on the above polymer to obtain a vinyl polymer A-3. The properties of vinyl polymer A-3 are shown in Table 1.

Production Example 4 (Production of vinyl polymer A-4)
A polymer was obtained by performing the same operation as in the polymerization step of Synthesis Example 1 except that the raw materials used and the reactor internal / external temperature were changed as shown in Table 1. As a result of GPC measurement of the polymer, Mn was 1,900, Mw was 2,900, and the viscosity was 1,030 mPa · s. The double bond concentration determined by ¹ H-NMR measurement was 0.30 meq / g.
Thereafter, the same operation as in the post-treatment step of Synthesis Example 1 was performed on the above polymer to obtain a vinyl polymer A-4. The properties of the vinyl polymer A-4 are shown in Table 1.

Production Example 5 (Production of vinyl polymer A-5)
A polymer was obtained by performing the same operation as in the polymerization step of Synthesis Example 1 except that the raw materials used and the reactor internal / external temperature were changed as shown in Table 1. As a result of GPC measurement of the polymer, Mn was 1,000, Mw was 1,500, and the viscosity was 700 mPa · s. The double bond concentration determined by ¹ H-NMR measurement was 0.22 meq / g.
Thereafter, the polymer was subjected to the same operation as in the post-treatment step of Synthesis Example 1 to obtain a vinyl polymer A-5. Properties of the vinyl polymer A-5 are shown in Table 1.

Production Example 6 (Production of vinyl polymer A-6)
A vinyl polymer A-6 was obtained in the same manner as in the polymerization step of Synthesis Example 1 except that the raw materials used and the temperature inside and outside the reactor were changed as shown in Table 1. At this time, the reaction was continued for 50 minutes from the reaction liquid collection start point, and 2.4 kg of the reaction liquid was recovered. The properties of the vinyl polymer A-6 are shown in Table 1.

Production Example 7 (Production of vinyl polymer A-7)
A stirred tank reactor having a capacity of 2000 mL equipped with an oil jacket was charged with 1000 g of vinyl polymer A-6, and the atmosphere in the reactor was purged with nitrogen while flowing 100 mL / min of nitrogen. Thereafter, the internal temperature was raised to 90 ° C., 36 g of perhexyl O was added, and in this state, the mixture was stirred for 16 hours to perform a radical addition reaction to obtain a vinyl polymer A-7. Properties of the vinyl polymer A-7 are shown in Table 1.

Production Example 8 (Production of vinyl polymer A-8)
Into a 1,000 mL pressurized stirred tank reactor equipped with an oil jacket, vinyl polymer A-6 (700 g) and dried 5% palladium carbon (3.5 g) were placed, and the atmosphere in the reactor was evacuated. I made it. Thereafter, the internal temperature was heated to 130 ° C. and pressurized to about 1.5 MPa with hydrogen. In this state, the mixture was stirred for 8 hours to perform a hydrogenation reaction. After purging the pressure, filtration was performed using diatomaceous earth “Radiolite # 100” manufactured by Showa Chemical Industry Co., Ltd. as a filter aid to obtain a vinyl polymer A-8. Properties of the vinyl polymer A-8 are shown in Table 1.

Production Example 9 (Production of vinyl polymer A-9)
A polymer was obtained by performing the same operation as in the polymerization step of Synthesis Example 1 except that the raw materials used and the reactor internal / external temperature were changed as shown in Table 1. As a result of GPC measurement of the polymer, Mn was 1,100, Mw was 1,600, and the viscosity was 800 mPa · s. The double bond concentration determined by ¹ H-NMR measurement was 0.23 meq / g.
Thereafter, the polymer was subjected to the same operation as in the post-treatment step of Synthesis Example 1 to obtain a vinyl polymer A-9. The properties of vinyl polymer A-9 are shown in Table 1.

Details of the compounds shown in Table 1 are as follows.
MA: methyl acrylate BA: butyl acrylate HA: 2-ethylhexyl acrylate MEA: 2-methoxyethyl acrylate MMA: methyl methacrylate IPA: isopropyl alcohol MEK: methyl ethyl ketone DTBP: di-t-butyl peroxide

≪Preparation and evaluation of active energy ray curable composition≫
Examples 1 to 8 and Comparative Example 1
The vinyl polymer (component A), the (meth) acryloyl group-containing compound (component B) and the photopolymerization initiator (component C) obtained in the above production examples were blended in the proportions shown in Table 2, and mixed rotor (trade name) : MIX-ROATER VMR-5, manufactured by ASONE) for 2 hours to obtain a curable composition. The curing rate of each curable composition was measured and listed in Table 2. Moreover, the light transmittance and adhesiveness were evaluated about the hardened | cured material obtained from each curable composition, and the result was shown in Table 2.

Examples 9-12
A vinyl polymer (component A), a (meth) acryloyl group-containing compound (component B) and a photopolymerization initiator (component C) are blended in the proportions shown in Table 3, and a mix rotor (trade name: MIX-ROATER VMR-5) And made by ASONE) for 2 hours to obtain a curable composition. The curing rate of each curable composition was measured and listed in Table 3. Moreover, compatibility (haze) and adhesiveness were evaluated about the hardened | cured material obtained from each curable composition, and the result was shown in Table 3.

Details of the compounds shown in Tables 2 to 3 are as follows.
HX-220: Caprolactone-modified hydroxypivalic acid neopentyl glycol diacrylate (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYARAD HX-220”)
M-270: Polypropylene glycol diacrylate (trade name “Aronix M-270” manufactured by Toagosei Co., Ltd.) (Aronix is a registered trademark)
FA-512AS: Dicyclopentenyloxyethyl acrylate (manufactured by Hitachi Chemical Co., Ltd., trade name “FANCRYL FA-512AS”)
Irgacure 184: 1-hydroxy-cyclohexyl-phenyl-ketone (BASF)

Examples 1 to 12 belong to the active energy ray-curable composition of the present invention, and are evaluated with respect to a curable composition having a degree of curing satisfying a certain curing rate even under low irradiation conditions. It is a result. The obtained cured product exhibited good transparency and was excellent in adhesion to the substrate. Further, from the results of Examples 9 to 12, the vinyl polymer as the component (A) has an amount of double bond of 0.01 to 0.50 meq / g (0.02 to 0.36 meq / g). In 9 to 11, a result that the transparency of the obtained cured product was more excellent was obtained. This was presumed to be a result of improved compatibility between the vinyl polymer and the matrix derived from the component (B).
On the other hand, Comparative Example 1 relates to a curable composition that does not have a sufficient curing rate, and the obtained cured product was inferior in adhesion to the substrate.

The active energy ray-curable composition of the present invention is excellent in curability, and the resulting cured product is excellent in adhesion to a substrate and light transmittance. Therefore, it is suitably used as an optical adhesive layer for the purpose of laminating a transparent substrate, particularly an optical member.

Claims

An active energy ray-curable composition comprising a vinyl polymer (A), a (meth) acryloyl group-containing compound (B) and a photopolymerization initiator (C),
When the curable composition was applied to a film thickness of 15 μm and irradiated with light using a mercury xenon lamp as a light source under the condition of illuminance of 5 mW / cm 2 with a UV-A wavelength, the following formula (1) An active energy ray-curable composition having a cure rate represented by 0.3% / second or more.
[Curing rate] (% / second) = (reaction rate of (meth) acryloyl group 20 seconds after light irradiation−reaction rate of (meth) acryloyl group 10 seconds after light irradiation) / light irradiation time (10 seconds) (1)
The active energy ray-curable composition according to claim 1, wherein the curing rate is 0.3% to 10% / second.
The active energy ray-curable composition according to claim 1 or 2, wherein the vinyl polymer (A) has a double bond in a molecule of 0.01 meq / g or more and 0.50 meq / g or less.
4. The vinyl polymer (A) according to any one of claims 1 to 3, wherein the structural monomer unit contains (meth) acrylic acid ester having an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms. The active energy ray-curable composition according to claim 1.
The active energy ray-curable composition according to any one of claims 1 to 4, wherein the vinyl polymer (A) is obtained by a high-temperature continuous polymerization method under a polymerization temperature condition of 100 to 350 ° C.
The active energy ray-curable composition according to any one of claims 1 to 5, wherein the vinyl polymer (A) has a weight average molecular weight of 500 or more and 100,000 or less.
The proportion of the vinyl polymer (A) and the (meth) acryloyl group-containing compound (B) used is (A) / (B) = 10 to 95/5 to 90 (mass ratio). The active energy ray-curable composition according to any one of 1 to 6.
The photopolymerization initiator (C) is contained in an amount of 0.5 to 5 parts by mass with respect to 100 parts by mass of the total amount of the vinyl polymer (A) and the (meth) acryloyl group-containing compound (B). The active energy ray-curable composition according to claim 1.
An optical adhesive layer obtained by curing the active energy ray-curable composition according to any one of claims 1 to 8.