JP2019164293A - Image display device, copolymer solution, and film material - Google Patents

Abstract

To provide an image display device that includes a shock absorption layer excellent in shock resistance and heat resistance, and a copolymer solution and a film material that can form such a shock absorption layer.SOLUTION: An image display device 10 comprises: an image display member 13; and a shock absorption layer 11 that is arranged on one side or both sides of the image display member 13. The shock absorption layer 11 contains copolymers containing 50 to 90 parts by mass of a monomer unit derived from alkyl (meth)acrylate having an alkyl group having 1 to 18 carbon atoms, 5 to 30 parts by mass of a monomer unit derived from (meth)acrylate having a hydroxyl group, and 5 to 30 parts by mass of a monomer unit derived from a siloxane compound having an ethylenically unsaturated group. The weight average molecular weight of the copolymers is 300,000 to 1,500,000, and the glass transition point of the copolymers is -75 to -45°C. The copolymers may be crosslinked with each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display device, a copolymer solution, and a film material.

  Image display devices such as organic electroluminescence (organic EL) and liquid crystal are used for protecting an image display member, a function improving member that improves the characteristics of light emitted from the image display member, and protecting the image display member from oxygen, moisture, and the like. It is constituted by laminating a plurality of members such as a barrier member and a fixing member for fixing these members (for example, see Patent Document 1).

JP 2017-120758 A

  In recent years, reduction in weight, thickness, or flexibility of image display devices has been studied. However, with such a study, the strength of each member tends to decrease. For example, when an impact such as external stress or pressure during assembly of the image display device is applied to the image display device, the image display member, the barrier member, or the like may be damaged. Therefore, it has been studied to introduce an impact absorbing layer that can also act as a fixing member in the image display device. From the viewpoint of adhesiveness as a fixing member, the shock absorbing layer is also required to be free from floating, peeling off, foaming and the like in a high temperature environment.

  The present invention has been made in view of such a situation, and an image display device provided with an impact absorption layer excellent in impact resistance and heat resistance, and a common weight capable of forming such an impact absorption layer. It aims at providing a united solution and a film material.

  One aspect of the present invention includes an image display member and an impact absorption layer disposed on one side or both sides of the image display member, and the impact absorption layer has an alkyl (meth) having an alkyl group having 1 to 18 carbon atoms. 50 to 90 parts by mass of monomer units derived from acrylate, 5 to 30 parts by mass of monomer units derived from (meth) acrylate having a hydroxyl group, and monomers derived from a siloxane compound having an ethylenically unsaturated group A copolymer containing 5 to 30 parts by mass of the unit is contained, the weight average molecular weight of the copolymer is 300,000 to 1,500,000, and the glass transition point of the copolymer is −75 to −45 ° C. There is provided an image display device in which the copolymers may be cross-linked with each other.

  In another aspect, the present invention provides a monomer unit derived from 50 to 90 parts by mass of a monomer unit derived from an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms and a (meth) acrylate having a hydroxyl group. A copolymer containing 5 to 30 parts by mass of a unit and 5 to 30 parts by mass of a monomer unit derived from a siloxane compound having an ethylenically unsaturated group, and an organic solvent, and a weight average of the copolymer Copolymer solution having a molecular weight of 300,000 to 1,500,000, a glass transition point of the copolymer of −75 to −45 ° C., and used for forming a shock absorbing layer of an image display device I will provide a.

  The present invention may relate to an application of the copolymer solution for producing a shock absorbing layer of an image display device and an application for producing an image display device.

  In another aspect, the present invention is a film material comprising a base material and a resin layer disposed on the base material, wherein the resin layer is used to form an impact absorbing layer of an image display device. , 50 to 90 parts by mass of a monomer unit derived from an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, 5 to 30 monomer units derived from a (meth) acrylate having a hydroxyl group Containing a copolymer containing 5 to 30 parts by mass of a monomer unit derived from a siloxane compound having an ethylenically unsaturated group, and having a weight average molecular weight of 300,000 to 1,500, And a glass transition point of the copolymer is −75 to −45 ° C., and the copolymer may be crosslinked with each other. The haze of the resin layer may be 5% or less.

  ADVANTAGE OF THE INVENTION According to this invention, the image display apparatus provided with the impact-absorbing layer excellent in impact resistance and heat resistance, and the copolymer solution and film material which can form such an impact-absorbing layer are provided.

It is sectional drawing which shows typically one Embodiment of an image display apparatus. It is sectional drawing which shows typically one Embodiment of a film material. It is the schematic which shows an example of the measuring apparatus of an acceleration decay rate typically. It is the schematic which shows an example of an impact resistance evaluation apparatus typically.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. However, the present invention is not limited to the following embodiments.

  In this specification, (meth) acrylate means an acrylate or a corresponding methacrylate. The same applies to other similar expressions such as a (meth) acryloyl group.

<Image display device>
An image display device according to an embodiment includes an image display member and a shock absorbing layer disposed on one side or both sides of the image display member. FIG. 1 is a cross-sectional view schematically showing an embodiment of an image display device. The image display device 10 illustrated in FIG. 1 includes a substrate 12, a shock absorbing layer 11, an image display member 13, a function improving member 14, and a barrier member 15 in this order. The image display device 10 may include the substrate 12, the image display member 13, the shock absorbing layer 11, the function improving member 14, and the barrier member 15 in this order. The shock absorbing layer 11 is further disposed on the opposite side of the image display member 13 of the substrate 12, between the function improving member 14 and the barrier member 15, or on the opposite side of the barrier member 15 from the function improving member 14. May be.

  The image display device 10 is not particularly limited, but may be a liquid crystal device, an organic electroluminescence (organic EL) device, or the like. The image display device 10 is preferably an organic EL device.

  The substrate 12 may be a glass substrate, a metal substrate, a resin substrate, or the like. The substrate 12 may be a flexible substrate or a thin glass substrate.

  In one embodiment, the image display member 13 may be an organic EL light emitting element including a pixel electrode, an intermediate layer including an organic light emitting layer, and a counter electrode in this order. The pixel electrode may be a reflective electrode. The counter electrode may be a transparent electrode. The intermediate layer includes an organic light emitting layer. In addition to the organic light emitting layer, the intermediate layer includes a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), an electron injection layer (EIL), and the like. Also good.

  The function improving member 14 is a layer having a function of improving the characteristics of the light emitted from the image display member 13, and those generally used in the organic EL field can be used.

  The barrier member 15 is a sealing layer for protecting from oxygen, moisture, and the like, and those generally used in the organic EL field can be used.

  The shock absorbing layer 11 contains a specific copolymer described later. When the shock absorbing layer 11 contains a specific copolymer, flexibility and toughness can be imparted, and high impact resistance can be achieved. The copolymers may be cross-linked with each other. That is, in the copolymer, the copolymer and the copolymer may be crosslinked directly or via a crosslinking agent. In the present specification, “copolymers are cross-linked to each other” means that two or more copolymers are cross-linked directly or via a cross-linking agent. The shock absorbing layer 11 can be formed from a copolymer solution or a film material described later.

<Copolymer solution>
The copolymer solution according to one embodiment contains a specific copolymer and an organic solvent, and is used for forming a shock absorbing layer of an image display device.

  The copolymer is 50 to 90 parts by mass of monomer units derived from an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms (hereinafter sometimes referred to as “monomer (A)”). 5-30 parts by mass of a monomer unit derived from a (meth) acrylate having a hydroxyl group (hereinafter sometimes referred to as “monomer (B)”), and a siloxane compound having an ethylenically unsaturated group (hereinafter, referred to as “monomer (B)”). 5 to 30 parts by mass of a monomer unit derived from “sometimes referred to as“ monomer (C) ”). Such a copolymer can be obtained by copolymerizing a monomer mixture having the same content ratio as each monomer unit. It is more preferable that the polymerization rate is substantially close to 100% by mass.

  The monomer (A) is a compound having a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms and one (meth) acryloyl group. Examples of the monomer (A) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, and n-pentyl (meta ) Acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate Cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and the like. A monomer (A) may be used individually by 1 type or in combination of 2 or more types. The monomer (A) preferably contains an alkyl (meth) acrylate having a linear or branched alkyl group having 1 to 18 carbon atoms, n-butyl (meth) acrylate, isooctyl (meth) acrylate, More preferably, 2-ethylhexyl (meth) acrylate or n-octyl (meth) acrylate is included, and more preferably n-butyl (meth) acrylate or 2-ethylhexyl (meth) acrylate is included. The monomer (A) is preferably an alkyl acrylate rather than an alkyl methacrylate.

  The content of the monomer unit derived from the monomer (A) is 50 to 90 parts by mass, preferably 60 to 90 parts by mass with respect to 100 parts by mass of all monomer units of the copolymer. More preferably, it is 65-85 mass parts. When the content of the monomer unit derived from the monomer (A) is in such a range, when the resin layer is formed, the adhesion between the resin layer and the substrate tends to be further improved. It is in.

  The monomer (B) is a compound having a hydroxyl group and one (meth) acryloyl group. Examples of the monomer (B) include 2-hydroxyethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 1-hydroxy. Hydroxyalkyl (meth) acrylates such as propyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 1-hydroxybutyl (meth) acrylate, etc. Is mentioned. A monomer (B) may be used individually by 1 type or in combination of 2 or more types. The monomer (B) preferably contains hydroxyalkyl (meth) acrylate, and more preferably contains 2-hydroxyethyl (meth) acrylate.

  The content of the monomer unit derived from the monomer (B) is 5 to 30 parts by mass, preferably 10 to 25 parts by mass with respect to 100 parts by mass of all monomer units of the copolymer. is there. When the content of the monomer unit derived from the monomer (B) is in such a range, whitening due to wet heat tends to be further suppressed, and the cohesiveness tends to be further improved.

  A monomer (C) is a compound which has ethylenically unsaturated groups, such as a (meth) acryloyl group, a styryl group, a cinnamic acid ester group, a vinyl group, an allyl group, and has a siloxane structure, for example. Examples of the monomer (C) include compounds represented by the following general formula (a) or (b). A monomer (C) may be used individually by 1 type or in combination of 2 or more types.

In formula (a), R ¹ represents a hydrogen atom or a methyl group, R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom or a methyl group, and R ⁸ represents 1 Represents a divalent hydrocarbon group, L ¹ represents a divalent hydrocarbon group or a single bond in which an oxygen atom may be interposed, and m represents an integer of 1 or more.

In formula (b), R ¹ represents a hydrogen atom or a methyl group, R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom or a methyl group, and L ¹ and L ² independently represents a divalent hydrocarbon group or a single bond in which an oxygen atom may intervene, and n represents an integer of 1 or more.

  Examples of the monovalent hydrocarbon group include an alkyl group having 1 to 6 carbon atoms or a phenyl group. As a bivalent hydrocarbon group, a C1-C20 alkylene group is mentioned, for example.

  The content of the monomer unit derived from the monomer (C) is 5 to 30 parts by mass, preferably 5 to 20 parts by mass with respect to 100 parts by mass of the total monomer units of the copolymer. More preferably, it is 5-15 mass parts. When the content of the monomer unit derived from the monomer (C) is in such a range, the flexibility and toughness of the resulting resin layer can be improved, and higher impact resistance can be obtained. There is a tendency to be able to.

  As long as the copolymer does not significantly impair the effects of the present invention, other than the monomer unit derived from the monomer (A), the monomer (B), and the monomer (C) The monomer unit derived from the monomer may further be included. Examples of other monomers include compounds having one (meth) acryloyl group other than monomer (A), monomer (B), and monomer (C), and other than (meth) acryloyl groups And a compound having a polymerizable group. Examples of the compound having one (meth) acryloyl group include (meth) acrylic acid, (meth) acrylamide, (meth) acrylamide derivatives, (meth) acrylate having an alkylene glycol chain, and (meth) acrylate having an aromatic ring. , (Meth) acryloylmorpholine, tetrahydrofurfuryl (meth) acrylate, and (meth) acrylate having an isocyanate group. Examples of the compound having a polymerizable group other than the (meth) acryloyl group include acrylonitrile, styrene, vinyl acetate, ethylene, propylene, and divinylbenzene.

  Examples of (meth) acrylamide derivatives include N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, and N-isopropyl (meth). Examples include acrylamide, N, N-diethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide. Examples of the (meth) acrylate having an alkylene glycol chain include polyethylene such as diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, and hexaethylene glycol mono (meth) acrylate. Glycol mono (meth) acrylate; Polypropylene glycol mono (meth) acrylate such as dipropylene glycol mono (meth) acrylate, tripropylene glycol mono (meth) acrylate, octapropylene glycol mono (meth) acrylate; Dibutylene glycol mono (meth) Polybutylene glycol mono (meth) acrylates such as acrylate and tributylene glycol mono (meth) acrylate; methoxy Liethylene glycol (meth) acrylate, methoxytetraethylene glycol (meth) acrylate, methoxyhexaethylene glycol (meth) acrylate, methoxyoctaethylene glycol (meth) acrylate, methoxynonaethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate And alkoxy polyalkylene glycol (meth) acrylates such as methoxyheptapropylene glycol (meth) acrylate, ethoxytetraethylene glycol (meth) acrylate, butoxyethylene glycol (meth) acrylate, and butoxydiethylene glycol (meth) acrylate. Examples of the (meth) acrylate having an aromatic ring include benzyl (meth) acrylate and phenoxyethyl (meth) acrylate. Examples of the (meth) acrylate having an isocyanate group include 2- (2-methacryloyloxyethyloxy) ethyl isocyanate and 2- (meth) acryloyloxyethyl isocyanate.

  The weight average molecular weight (Mw) of the copolymer is 300,000 to 1,500,000, preferably 350,000 to 1,200,000. When the weight average molecular weight (Mw) of the copolymer is 300,000 or more, the cohesiveness is increased and heat resistance tends to be easily obtained. When the weight average molecular weight (Mw) of the copolymer is 1,500,000 or less, a resin layer (impact absorbing layer) having a uniform thickness tends to be easily obtained when forming a film material. In addition, a weight average molecular weight (Mw) can be calculated | required from the value converted using the calibration curve of a standard polystyrene using gel permeation chromatography (GPC).

  The glass transition point (Tg) of the copolymer is −75 to −45 ° C., preferably −70 to −50 ° C. When the glass transition point (Tg) of the copolymer is −75 ° C. or higher, the cohesiveness is increased and good handling properties tend to be easily obtained. When the glass transition point (Tg) of the copolymer is −45 ° C. or lower, the flexibility of the resulting resin layer tends to be improved and high impact resistance tends to be imparted.

In addition, the glass transition point (Tg) of a copolymer means what was computed by the following relational expressions (FOX formula).
1 / Tg = Σ (X _i / Tg _i )
[In the above formula, Tg represents the glass transition point (K) of the copolymer. X _i represents a mass fraction of each monomer, and X ₁ + X ₂ +... + X _i +... + X _n = 1. Tg _i indicates the glass transition temperature (K) of a homopolymer of each monomer. ]

  The content of the copolymer is preferably 10 to 80% by mass, more preferably 15 to 70% by mass, and further preferably 20 to 60% by mass based on the total mass of the copolymer solution.

  The organic solvent is not particularly limited, but is preferably an organic solvent that can be used in solution polymerization described later. By using such an organic solvent, it can be used as a copolymer solution as it is without isolation of the copolymer. Examples of such organic solvents include aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, aliphatic alcohols such as n-propyl alcohol and isopropyl alcohol, acetone, methyl ethyl ketone, and methyl. Examples thereof include ketones such as isobutyl ketone and cyclohexanone. Among these, the organic solvent is preferably ethyl acetate, methyl ethyl ketone, or toluene from the viewpoint of controlling the molecular weight of the copolymer.

  The content of the organic solvent is preferably 20 to 90% by mass, more preferably 30 to 85% by mass, and further preferably 40 to 80% by mass based on the total mass of the copolymer solution.

  The copolymer solution can be prepared, for example, by solution polymerization of each monomer in an organic solvent. Uniform copolymerization of highly hydrophilic monomer (B) and highly hydrophobic monomer (C) by solvation effect by solution polymerization of each monomer using an organic solvent Thus, high transparency (for example, haze of 5.0% or less) can be imparted to the resin layer (impact absorbing layer). In addition, the copolymer solution is obtained by, for example, obtaining a copolymer using a known polymerization method such as emulsion polymerization, suspension polymerization, bulk polymerization, and then mixing the obtained copolymer with an organic solvent. Can also be made.

  As the polymerization initiator for synthesizing the copolymer, a compound that generates a radical by heat can be used. Examples of the polymerization initiator include organic peroxides such as benzoyl peroxide and lauroyl peroxide; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), and the like. An azo compound is mentioned.

  The copolymer solution may contain various additives as required. Examples of the additive include a crosslinking agent such as a photocrosslinking agent and a thermal crosslinking agent from the viewpoint of increasing the cohesive strength of the copolymer.

  Examples of the photocrosslinking agent include alkylene diol di (meth) acrylate having an alkylene group having 1 to 20 carbon atoms; alkylene glycol di (meth) acrylate such as polyethylene glycol di (meth) acrylate and polypropylene glycol di (meth) acrylate. Bisphenol type di (meth) acrylates such as ethoxylated bisphenol A di (meth) acrylate, ethoxylated bisphenol F di (meth) acrylate and bisphenol A type epoxy (meth) acrylate; urethane di (meth) acrylate having a urethane bond, etc. Can be mentioned.

  The urethane di (meth) acrylate having a urethane bond may have a polyalkylene glycol chain from the viewpoint of good compatibility with other components, and from the viewpoint of ensuring transparency, an alicyclic structure. You may have. When the compatibility between the photocrosslinking agent and the copolymer is low, the resin layer (impact absorbing layer) formed from the copolymer solution may become cloudy.

  From the viewpoint of further suppressing the occurrence of bubbles and peeling under high temperature or high temperature and high humidity, the weight average molecular weight of the photocrosslinking agent is preferably 100,000 or less, more preferably 300 to 100,000, and even more preferably 500 to 80. , 000.

  The content in the case of using a photocrosslinking agent is preferably 15% by mass or less, more preferably 10% by mass or less, and further preferably 7% by mass or less, based on the total mass of the copolymer. Within such a range, a resin layer (shock absorbing layer) having sufficient adhesion tends to be obtained. The lower limit of the content of the photocrosslinking agent is not particularly limited, but is preferably 0.1% by mass or more, more preferably 2% by mass or more, and still more preferably 3% by mass from the viewpoint of improving film formability. That's it.

  As a thermal crosslinking agent, an isocyanate compound, a melamine compound, an epoxy compound etc. are mentioned, for example. As the thermal crosslinking agent, it is preferable to use a polyfunctional thermal crosslinking agent such as trifunctional or tetrafunctional from the viewpoint of forming a network structure that gently spreads in the resin layer (impact absorbing layer).

  The thermal crosslinking agent is preferably an isocyanate compound, more preferably a polyisocyanate compound, from the viewpoint of reactivity. Examples of the polyisocyanate compound include a polyfunctional hexamethylene diisocyanate compound which is a reaction product of hexamethylene diisocyanate trimer, triol such as trimethylolpropane, diol or monofunctional alcohol and hexamethylene diisocyanate. .

  The content in the case of using a thermal crosslinking agent is preferably 5% by mass or less, more preferably 2% by mass or less, and further preferably 1% by mass or less, based on the total mass of the copolymer. When the content of the thermal crosslinking agent is within such a range, a resin layer (shock absorbing layer) having sufficient adhesion can be obtained. The lower limit of the content of the thermal crosslinking agent is not particularly limited, but is preferably 0.01% by mass or more from the viewpoint of improving the film formability.

  When either the copolymer or the crosslinking agent is a curing system using active energy rays, a photopolymerization initiator is required. A photoinitiator accelerates | stimulates hardening reaction by irradiation of an active energy ray. Active energy rays refer to ultraviolet rays, electron beams, α rays, β rays, γ rays and the like.

  Although a photoinitiator is not specifically limited, Well-known materials, such as a benzophenone compound, an anthraquinone compound, a benzoyl compound, a sulfonium salt, a diazonium salt, an onium salt, can be used.

  Examples of the photopolymerization initiator include benzophenone, N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N, N ′, N′-tetraethyl-4,4. '-Diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, α-hydroxyisobutylphenone, 2-ethylanthraquinone, t-butylanthraquinone, 1,4-dimethylanthraquinone, 1-chloroanthraquinone, 2,3-dichloroanthraquinone , 3-chloro-2-methylanthraquinone, 1,2-benzoanthraquinone, 2-phenylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl phenyl ketone , 2, 2 Aromatic ketone compounds such as dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-diethoxyacetophenone; benzoin, methylbenzoin, ethyl Benzoin compounds such as benzoin; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether and benzoin phenyl ether; benzyl compounds such as benzyl and benzyldimethyl ketal; β- (acridin-9-yl) (meth) acryl Ester compounds such as acids; acridine compounds such as 9-phenylacridine, 9-pyridylacridine, 1,7-diacridinoheptane; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- ( o-ku Rophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5 -Diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) 5-phenylimidazole dimer, 2- (2, 2,4,5-triarylimidazole dimers such as 4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer; 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone; 2-methyl-1- [4- (methylthio) phenyl] -2 Morpholino-1-propane; bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) . These photopolymerization initiators may be used alone or in combination of two or more.

  Examples of the photopolymerization initiator that does not color the copolymer solution include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- (2-hydroxy Α-hydroxyalkylphenone compounds such as ethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one; bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2, Acylphosphine oxide compounds such as 6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; oligo (2-hydroxy-2-methyl-1- ( 4- (1-methylvinyl) phenyl) propanone) That.

  In order to form a particularly thick resin layer (shock absorbing layer), the photopolymerization initiator may be, for example, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl)- Acylphosphine oxide compounds such as 2,4,4-trimethyl-pentylphosphine oxide and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide may also be included.

  The content of the photopolymerization initiator is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass, and still more preferably 0.1 to 1.5% based on the total mass of the copolymer solution. % By mass. When the content of the photopolymerization initiator is 5% by mass or less, the transmittance is high, the hue is not yellowish, and a resin layer (impact absorbing layer) excellent in transparency tends to be obtained. It is in.

  Examples of additives other than the crosslinking agent include a polymerization inhibitor such as paramethoxyphenol added for the purpose of enhancing the storage stability of the copolymer solution, and a resin layer obtained by photocuring the copolymer solution (impact absorption) Photostabilization such as antioxidants such as triphenyl phosphite added for the purpose of increasing the heat resistance of the layer) and HALS (Hindered Amine Light Stabilizer) added for the purpose of increasing the resistance of the copolymer solution to light such as ultraviolet rays Examples thereof include a silane coupling agent to be added in order to improve the adhesiveness of the copolymer solution to the agent and glass.

<Film material>
The film material which concerns on one Embodiment is equipped with a base material and the resin layer arrange | positioned on a base material, and a resin layer is used in order to form the impact absorption layer of an image display apparatus. The said resin layer can be formed from the copolymer solution mentioned above.

  FIG. 2 is a cross-sectional view schematically showing an embodiment of the film material. As shown in FIG. 2, the film material 20 may include a resin layer 21, and one base material 22 and the other base material 23 stacked so as to sandwich the resin layer 21.

  The base material 22 is preferably a material that is more peelable than the base material 23. Examples of the base material 22 include polymer films such as polyethylene terephthalate (PET), polypropylene, and polyethylene. Among these, it is preferable that the base material 22 is a PET film. From the viewpoint of workability, the thickness of the base material 22 is preferably 50 to 200 μm, more preferably 60 to 150 μm, and still more preferably 70 to 130 μm.

  The planar shape of the base material 22 is larger than the planar shape of the resin layer 21, and the outer edge of the base material 22 preferably projects outward from the outer edge of the resin layer 21. The width at which the outer edge of the substrate 22 protrudes from the outer edge of the resin layer 21 is preferably 2 to 20 mm, more preferably 4 to 10 mm, from the viewpoint of ease of handling, ease of peeling, and reduction of adhesion of dust and the like. is there. When the planar shape of the resin layer 21 and the base material 22 is a substantially rectangular shape such as a substantially rectangular shape, the width at which the outer edge of the base material 22 protrudes from the outer edge of the resin layer 21 is preferably 2 on at least one side. -20 mm, more preferably 4 to 10 mm on at least one side, further preferably 2 to 20 mm on all sides, particularly preferably 4 to 10 mm on all sides.

  The base material 23 is preferably a light-peeling base material than the base material 22. Examples of the base material 23 include polymer films such as polyethylene terephthalate (PET), polypropylene, and polyethylene. Among these, it is preferable that the base material 23 is a PET film. From the viewpoint of workability, the thickness of the base material 23 is preferably 25 to 150 μm, more preferably 30 to 100 μm, and still more preferably 40 to 80 μm.

  The planar shape of the base material 23 is larger than the planar shape of the resin layer 21, and it is preferable that the outer edge of the base material 23 projects outward from the outer edge of the resin layer 21. The width at which the outer edge of the base material 23 protrudes from the outer edge of the resin layer 21 is preferably 2 to 20 mm, more preferably 4 to 10 mm, from the viewpoint of ease of handling, ease of peeling, and reduction of adhesion of dust and the like. is there. In the case where the planar shape of the resin layer 21 and the base material 23 is a substantially rectangular shape such as a substantially rectangular shape, the width at which the outer edge of the base material 23 protrudes from the outer edge of the resin layer 21 is preferably 2 on at least one side. -20 mm, more preferably 4 to 10 mm on at least one side, further preferably 2 to 20 mm on all sides, particularly preferably 4 to 10 mm on all sides.

  The peel strength between the base material 23 and the resin layer 21 is preferably lower than the peel strength between the base material 22 and the resin layer 21. As a result, the base material 22 is less likely to peel from the resin layer 21 than the base material 23. The peel strength can be adjusted, for example, by applying a surface treatment to the base material 22 and the base material 23. As the surface treatment method, for example, a release treatment of the base material with a silicone compound or a fluorine compound may be mentioned.

  A known technique can be used for forming the resin layer 21. For example, the resin layer 21 having an arbitrary thickness can be formed by applying the above-described copolymer solution onto the base material 22 and removing the organic solvent by drying. At this time, in the resin layer 21, the copolymers may be cross-linked with each other. That is, in the copolymer, the copolymer and the copolymer may be crosslinked directly or via a crosslinking agent. As a coating method, for example, a known method such as a flow coating method, a roll coating method, a gravure coating method, a wire bar coating method, or a lip die coating method can be used.

  After forming the resin layer 21 on the base material 22, the base material 23 is laminated | stacked on the resin layer 21, and a film material is produced. The resin layer 21 is sandwiched between the base material 23 and the base material 22. In order to control the peelability between the resin layer 21 and the base material 23 and the base material 22, the copolymer solution is allowed to contain a surfactant such as a polydimethylsiloxane-based surfactant or a fluorine-based surfactant. Also good.

  The thickness of the resin layer 21 is not particularly limited because it is appropriately adjusted depending on the intended use and method, but may be 10 to 5000 μm, 25 to 200 μm, 25 to 180 μm, or 25 to 150 μm. When the thickness of the resin layer 21 is in such a range, the impact absorbing layer can be more resistant to an externally applied impact.

  The light transmittance of the resin layer 21 to light in the visible light region (wavelength: 380 nm to 780 nm) is preferably 80% or more, more preferably 90% or more, and still more preferably 95% or more.

The haze of the resin layer 21 is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less. Haze is a value (%) representing turbidity, and is a total transmittance T _{t of} light irradiated through a lamp and transmitted through a sample, and a transmittance of light diffused and scattered in the sample. From _Td, it is obtained as ( _Td / _Tt ) × 100. These are defined by JIS K 7136, and can be easily measured by a commercially available turbidimeter (for example, product name “NDH-5000” manufactured by Nippon Denshoku Industries Co., Ltd.).

  According to the film material which concerns on this embodiment, storage and conveyance can be made easy, without damaging the resin layer 21. FIG.

  The resin layer 21 can be used, for example, as an impact absorbing layer of an image display device by being disposed on one side or both sides of the image display member.

  Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

<Preparation of copolymer solution>
The weight average molecular weight (Mw) of the copolymer produced in the example was determined from the value converted using a standard polystyrene calibration curve using gel permeation chromatography (GPC). The GPC measurement device and measurement conditions are as follows.
RI detector: L-3350 (manufactured by Hitachi High-Tech Science Co., Ltd.)
Eluent: THF
Column: Gelpac GL-R420 + R430 + R440 (manufactured by Hitachi Chemical Co., Ltd.)
Column temperature: 40 ° C
Flow rate: 2.0 mL / min

  The glass transition point (Tg) of the copolymer produced in the example was calculated by the above-described relational expression (FOX formula).

Example 1-1
In a reaction vessel equipped with a condenser, a thermometer, a stirrer, a dropping funnel, and a nitrogen introducing tube, 70.0 g of 2-ethylhexyl acrylate, 20.0 g of 2-hydroxyethyl acrylate, one-end methacryloyl-modified polysiloxane compound (Shin-Etsu Chemical) Made by Industrial Co., Ltd., product name “X-22-2426”, ethylenically unsaturated group equivalent: 12000 g / mol) 10.0 g, and ethyl acetate 145.0 g, and nitrogen substitution with 100 mL / min air volume, It heated from normal temperature (25 degreeC) to 65 degreeC in 15 minutes. Next, while maintaining the temperature at 65 ° C., a solution in which 0.1 g of lauroyl peroxide was dissolved in 5.0 g of ethyl acetate was added and reacted for 8 hours to obtain a copolymer having a solid content concentration of 40% by mass (Mw: 800,000). Glass transition point: −68.5 ° C.) Solution A-1 was obtained.

Example 1-2
Except for adding 70.0 g of n-butyl acrylate, 20.0 g of 2-hydroxyethyl acrylate, 10.0 g of one-end methacryloyl-modified polysiloxane compound used in Example 1-1, and 145.0 g of ethyl acetate to the reaction vessel. Was operated in the same manner as in Example 1-1 to obtain a copolymer (Mw: 850,000, glass transition point: −57.4 ° C.) solution A-2 having a solid content concentration of 40 mass%.

Example 1-3
Except for adding 70.0 g of n-butyl acrylate, 25.0 g of 2-hydroxyethyl acrylate, 5.0 g of one-end methacryloyl-modified polysiloxane compound used in Example 1-1, and 145.0 g of ethyl acetate to the reaction vessel. Were operated in the same manner as in Example 1-1 to obtain a copolymer (Mw: 850,000, glass transition point: −50.7 ° C.) solution A-3 having a solid concentration of 40% by mass.

Example 1-4
In a reaction vessel, 70.0 g of n-butyl acrylate, 20.0 g of 2-hydroxyethyl acrylate, 10.0 g of one-end methacryloyl-modified polysiloxane compound used in Example 1-1, 72.5 g of ethyl acetate, and methyl ethyl ketone 72. A copolymer (Mw: 500,000, glass transition point: −57.4 ° C.) solution A-4 having a solid content concentration of 40% by mass was operated in the same manner as in Example 1-1 except that 5 g was added. Obtained.

Comparative Example 1-1
The same procedure as in Example 1-1 was performed except that 80.0 g of 2-ethylhexyl acrylate, 20.0 g of 2-hydroxyethyl acrylate, and 145.0 g of ethyl acetate were added to the reaction vessel. A copolymer A (Mw: 800,000, glass transition point: −61.0 ° C.) solution A-5 was obtained.

Comparative Example 1-2
Similar to Example 1-1, except that 90.0 g of 2-ethylhexyl acrylate, 10.0 g of one-end methacryloyl-modified polysiloxane compound used in Example 1-1, and 145.0 g of ethyl acetate were added to the reaction vessel. Operation was performed to obtain a copolymer (Mw: 750,000, glass transition point: −76.9 ° C.) solution A-6 having a solid concentration of 40% by mass.

Comparative Example 1-3
The same procedure as in Example 1-1 was performed except that 80.0 g of n-butyl acrylate, 20.0 g of 2-hydroxyethyl acrylate, and 145.0 g of ethyl acetate were added to the reaction vessel. (Mw: 850,000, glass transition point: −47.2 ° C.) Solution A-7 was obtained.

Comparative Example 1-4
Except that 70.0 g of 2-ethylhexyl acrylate, 20.0 g of 2-hydroxyethyl acrylate, 10.0 g of one-end methacryloyl-modified polysiloxane compound used in Example 1-1, and 145.0 g of methyl ethyl ketone were added to the reaction vessel. The same operation as in Example 1-1 was performed to obtain a copolymer (Mw: 200,000, glass transition point: −68.5 ° C.) solution A-8 having a solid concentration of 40% by mass.

Comparative Example 1-5
Except for adding 70.0 g of n-butyl acrylate, 28.0 g of 2-hydroxyethyl acrylate, 2.0 g of one-end methacryloyl-modified polysiloxane compound used in Example 1-1, and 145.0 g of methyl ethyl ketone to the reaction vessel. By operating in the same manner as in Example 1-1, a copolymer A-9 having a solid content concentration of 40% (Mw: 700,000, glass transition point: −46.5 ° C.) was obtained.

Comparative Example 1-6
A copolymer was prepared except that 50.0 g of 2-ethylhexyl acrylate, 5.0 g of methyl methacrylate, 20.0 g of isobornyl acrylate, 25.0 g of 2-hydroxyethyl acrylate, and 145.0 g of ethyl acetate were added to the reaction vessel. In the same manner as in Example 1, a copolymer (Mw: 850,000, glass transition point: −29.4 ° C.) solution A-10 having a solid content concentration of 40% was obtained.

<Production of film material>
Example 2-1
Polyisocyanate compound (product name “Coronate HL” manufactured by Tosoh Corporation) 0.15 as a thermal crosslinking agent with respect to 100 parts by mass of copolymer of copolymer solution A-1 obtained in Example 1-1. Mass parts were mixed to prepare a mixed solution. Next, the mixed solution was applied to a 75 μm-thick polyethylene terephthalate (PET) film (base film A) having a release treatment on the surface using a bar coater so that the thickness after drying was 100 μm. The applied mixed solution was dried by heating at 100 ° C. for 10 minutes to form a resin layer. Thereafter, a PET film (base film B) having a thickness of 75 μm that had been subjected to a release treatment was placed on the resin layer, and the film was pasted with a hand roller at 9.8 N (1.0 kgf) to produce a film material.

Examples 2-2 to 2-4 and comparative examples 2-1 to 2-6
Except having changed the compounding quantity of each component into what is shown in Table 1, it carried out similarly to Example 2-1, and used the film material of Examples 2-2 to 2-4 and Comparative Examples 2-1 to 2-6. Produced. In Table 1, the unit of the numerical value of the blending amount is part by mass, and the numerical value of the copolymer solution means the blending amount of the solid content (copolymer).

<Evaluation>
About the film material obtained by each Example and the comparative example, it evaluated by the following method. The results are shown in Table 1.

1. Measurement of Acceleration Decay Rate FIG. 3 is a schematic diagram schematically showing an example of an acceleration decay rate measurement device. The acceleration attenuation rate measuring device 30 shown in FIG. 3 mainly supports the resin layer 31 provided in the film material, a fixing plate 32 (polymethyl methacrylate plate) for attaching the resin layer 31, and the fixing plate 32. The metal plate 33, a hammer 35 having an iron ball 34, and an acceleration sensor 36 disposed at the tip of the hammer 35 opposite to the iron ball 34 are configured.

The film materials of Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-6 were cut into a size of 50 mm × 50 mm, the base film B of the cut film material was peeled off, and the surface of the resin layer 31 was peeled off. Exposed. Thereafter, the exposed surface of the resin layer 31 was attached to a fixing plate 32 (length 100 mm × width 100 mm × thickness 3.0 mm) and pressed with a roller. Next, the base film A is peeled off from the resin layer 31 attached to the fixing plate 32, the surface of the resin layer 31 is exposed, and the fixing plate 32 and the metal plate 33 (length 150 mm × width 150 mm × thickness 10 mm) are in contact with each other. A measurement sample was obtained by placing in Next, a hammer 35 (mass 280 g) to which an iron ball 34 having a diameter of 11 mm is fixed is dropped from a position 20 mm in height in the vertical direction from the resin layer 31 of the measurement sample, and the acceleration sensor 36 (product of Showa Keiki Co., Ltd., product) The peak acceleration was measured using the name “MODEL-1340B”). The peak acceleration is obtained by reading the peak value (impact acceleration) from the waveform in which the absolute value is detected when the peak hold function built in the acceleration sensor is used. The measurement was performed in an environment of 23 ° C. The acceleration decay rate was calculated based on the following formula (A). The “peak acceleration when no resin layer is provided” in the formula (A) means a peak acceleration when measured only by the fixed plate 32 without providing the resin layer 31.
Acceleration decay rate (%)
= (Peak acceleration when not provided a resin layer [m / s 2] ^- peak acceleration when the resin layer is provided [m / s ^{2]) /} a If no resin layer provided peak acceleration [m / s ² ] × 100 (A)

2. Evaluation of Impact Resistance FIG. 4 is a schematic view schematically showing an example of an impact resistance evaluation apparatus. The impact resistance evaluation apparatus 40 shown in FIG. 4 mainly includes a resin layer 41 included in a film material, a glass plate 47 (float glass) for attaching the resin layer 41, and a glass plate 47 for fixing the glass layer 47. The fixing plate 42 (polymethyl methacrylate plate), a metal plate 43 that supports the fixing plate 42, and a hammer 45 having an iron ball 44 are configured.

The film materials of Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-6 were cut into a size of 90 mm × 90 mm, the base film B of the cut film material was peeled off, and the surface of the resin layer 41 was removed. Exposed. Thereafter, the exposed surface of the resin layer 41 was attached to a glass plate 47 (float glass, manufactured by Osaka Glass Co., Ltd., length 100 mm × width 100 mm × thickness 0.55 mm) and pressed with a roller. Next, the base film A is peeled from the resin layer 41 attached to the glass plate 47, the surface of the resin layer 41 is exposed, the glass plate 47, the fixing plate 42 (length 100 mm × width 100 mm × thickness 3.0 mm), And the evaluation sample was obtained by laminating | stacking so that it might become the order of the metal plate 43 (length 150mm x width 150mm x thickness 10mm). Next, a hammer 45 (mass 280 g) to which an iron ball 44 having a diameter of 11 mm was fixed was dropped from a position having a height of 10 mm in the vertical direction from the resin layer 41 of the evaluation sample, and the presence or absence of cracks or cracks in the float glass was evaluated. When the float glass was not cracked or cracked when dropped, the drop location was shifted and the hammer 45 was repeatedly dropped. The measurement was performed in an environment of 23 ° C. The evaluation criteria for impact resistance are as follows.
A: Cracks or cracks did not occur in the float glass after 10 hammer drops.
B: The float glass cracked or cracked when the hammer dropped less than 10 times.

3. Evaluation of heat resistance The heat resistance was evaluated by the deformation rate when the resin layer was subjected to stress at high temperature. The film materials of Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-6 were cut into a size of 7.0 mm in length and 10 mm in width, and the base film B of the cut out film material was peeled off to form a resin layer The surface of was exposed. Then, the surface of the exposed resin layer was pressed by hand onto quartz glass having a diameter of 10 mm and pasted. Next, the base film A attached to the quartz glass was peeled off to obtain an evaluation sample. In the compression load method of a thermomechanical analyzer (product name “EXSTAR6000” manufactured by Seiko Instruments Inc.), a compression indenter of Φ1.0 mm is brought into contact with the resin layer surface of the evaluation sample and left to stand for 1 minute without applying a load. After that, the amount of deformation when creeping for 5 minutes with a load of 30 mN was measured, and the deformation rate was calculated based on the following formula (B). The measurement was performed at 95 ° C. In addition, it has shown that durability under high temperature is so high that a deformation rate is small, and it means that heat resistance is high.
95 ° C. deformation rate (%) = deformation amount after compression (μm) / resin layer thickness before compression (μm) × 100 (B)

4). Measurement of haze The film materials of Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-6 were cut to a size of 50 mm × 50 mm, and the base film B of the cut film material was peeled off to remove the resin layer. The surface was exposed. Thereafter, the surface of the exposed resin layer of the film material was attached to float glass (length 50 mm × width 50 mm × thickness 2.7 mm) and pressed with a roller. Next, the base film A is peeled off from the resin layer attached to the float glass, and the surface of the resin layer is float glass (length 50 mm × width 50 mm × thickness 2.7 mm) in a vacuum state using a vacuum laminator. The laminated body was produced by pasting. Then, the produced laminated body was heat-pressed (autoclave process) on the conditions hold | maintained for 30 minutes with the temperature of 50 degreeC, the pressure of 0.5 MPa, and the measurement sample was obtained. About the obtained sample, haze was measured based on the following formula (C) according to JIS K7361 using a turbidimeter (Nippon Denshoku Industries Co., Ltd., product name "NDH-5000").
Haze (%) = (Td / Tt) × 100 (C)
Td: diffuse transmittance, Tt: total light transmittance

  The resin layers of the film materials of Examples 2-1 to 2-4 produced using the copolymer solutions A-1 to A-4 of Examples 1-1 to 1-4 are Comparative Examples 1-1 to 1. Compared to the resin layers of the film materials of Comparative Examples 2-1 to 2-6 prepared using the copolymer solutions A-5 to A-10 of -6, the impact resistance and the heat resistance were excellent. From this, it was suggested that when the resin layers of the film materials of Examples 2-1 to 2-4 were applied to an image display device, they could act as an impact absorbing layer.

  DESCRIPTION OF SYMBOLS 10 ... Image display apparatus, 11 ... Shock absorption layer, 12 ... Board | substrate, 13 ... Image display member, 14 ... Function improvement member, 15 ... Barrier member, 20 ... Film material, 21 ... Resin layer, 22, 23 ... Base material DESCRIPTION OF SYMBOLS 30 ... Acceleration decay rate measuring apparatus, 40 ... Impact resistance evaluation apparatus 31, 41 ... Resin layer, 32, 42 ... Fixed plate, 33, 43 ... Metal plate, 34, 44 ... Iron ball, 35, 45 ... Hammer, 36 ... acceleration sensor, 47 ... glass plate.

Claims (4)

An image display member, and a shock absorbing layer disposed on one or both sides of the image display member,
50 to 90 parts by mass of a monomer unit derived from an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, the monomer unit 5 derived from a (meth) acrylate having a hydroxyl group. Containing 30 parts by mass and a copolymer containing 5 to 30 parts by mass of monomer units derived from a siloxane compound having an ethylenically unsaturated group;
The copolymer has a weight average molecular weight of 300,000 to 1,500,000,
The glass transition point of the copolymer is -75 to -45 ° C,
An image display device in which the copolymers may be cross-linked with each other. 50 to 90 parts by mass of monomer units derived from alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, 5 to 30 parts by mass of monomer units derived from (meth) acrylate having a hydroxyl group, and ethylene A copolymer containing 5 to 30 parts by mass of a monomer unit derived from a siloxane compound having a polymerizable unsaturated group, and an organic solvent,
The copolymer has a weight average molecular weight of 300,000 to 1,500,000,
The glass transition point of the copolymer is -75 to -45 ° C,
A copolymer solution used for forming a shock absorbing layer of an image display device. A film material, comprising: a base material; and a resin layer disposed on the base material, wherein the resin layer is used to form a shock absorbing layer of an image display device,
50 to 90 parts by mass of monomer units derived from an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, and 5 to 30 monomer units derived from a (meth) acrylate having a hydroxyl group. Containing a copolymer containing 5 to 30 parts by mass of a monomer unit derived from a siloxane compound having a mass part and an ethylenically unsaturated group;
The copolymer has a weight average molecular weight of 300,000 to 1,500,000,
The glass transition point of the copolymer is -75 to -45 ° C,
A film material in which the copolymers may be cross-linked with each other.   The film material according to claim 3, wherein the haze of the resin layer is 5% or less.

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