JP2008303343A - Active energy radiation-curable composition, and display filter and display using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active energy radiation-curable composition excellent in visibility, adhesion and releasability, and a display filter and a display panel using the same. <P>SOLUTION: The active energy radiation-curable composition comprises at least a urethane acrylate prepolymer (A), an acrylate monomer (B) having carboxylic group and aromatic ring and/or aliphatic ring, and an acrylate monomer (C) having aromatic ring and/or aliphatic ring but no carboxy group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an active energy ray-curable composition excellent in visibility, adhesion, impact resistance and peelability, a display filter using the same, and a display.

  As a flat panel display, a plasma display, a liquid crystal display, an organic EL display and the like are widely used as a home display and a mobile phone display. These displays are usually equipped with a display filter for the purpose of protecting the display panel or preventing reflection. Conventionally, when these display filters are mounted on a display panel, a glass plate is interposed between the display panel and the display filter.

  The mounting method described above is superior in impact resistance because an air layer exists between the display panel and the glass plate, but is disadvantageous in terms of cost and production efficiency, and the display image is displayed because the air layer is interposed. There is a disadvantage that a phenomenon of multiple generation, a so-called double reflection phenomenon occurs. Accordingly, a method of attaching a display filter directly to a display panel via an adhesive layer has been attracting attention.

  Although the above-described display filter is directly attached to the display panel, it is excellent in cost and production efficiency, but the contrast and brightness are reduced due to the interface reflection caused by the difference in refractive index between the display panel and the adhesive layer, and the visibility is reduced. There is a problem of deterioration. In addition, this embodiment requires a pressure-sensitive adhesive layer that simultaneously satisfies the adhesion and peelability between the display panel and the display filter. Here, peelability refers to the display panel when the display filter is directly pasted to the display panel, when the pasting fails due to foreign matter biting or misalignment, or when the filter needs to be replaced. The display filter can be peeled off so as not to damage the display. That is, a pressure-sensitive adhesive layer having appropriate adhesion is required.

  It is known to use an active energy ray-curable composition as an adhesive layer for mounting a display filter on the display panel (for example, Patent Documents 1 and 2).

  On the other hand, increasing the refractive index of the pressure-sensitive adhesive layer used in the display filter reduces the refractive index difference with the glass substrate of the display panel, thereby reducing interface reflection and suppressing contrast and luminance reduction. It has been. For example, Patent Documents 3 and 4 propose increasing the refractive index of the pressure-sensitive adhesive by containing an aromatic ring-containing monomer such as styrene or phenoxyethyl acrylate.

  However, the techniques disclosed in Patent Documents 1 to 4 described above cannot simultaneously satisfy the visibility, adhesiveness, and peelability, which are the objectives of the present invention.

Further, in an embodiment in which the display filter is directly attached to the display panel, it is effective to increase the thickness of the pressure-sensitive adhesive layer as one means for improving the impact resistance. However, if the thickness of the pressure-sensitive adhesive layer is increased. For example, when the thickness is 50 μm or more, the surface of the pressure-sensitive adhesive layer tends to be wavy and uneven due to polymerization shrinkage when the active energy ray-curable composition is cured, which causes a problem that good smoothness cannot be obtained. .
JP 2000-63767 A JP 2006-171261 A JP 2003-13029 A JP 2003-342546 A

  Accordingly, an object of the present invention is to provide an active energy ray-curable composition that is excellent in impact resistance, has an appropriate adhesion and peelability to an adherend, and has a high refractive index, and the active energy ray. An object of the present invention is to provide a display filter and a display excellent in visibility, smoothness, adhesion and peelability by applying the curable composition to the pressure-sensitive adhesive layer.

The above object of the present invention has been basically achieved by the following invention.
(1) urethane acrylate prepolymer (A);
An acrylate monomer (B) having a carboxy group and an aromatic ring and / or an aliphatic ring;
An acrylate monomer (C) having an aromatic ring and / or an aliphatic ring and having no carboxy group,
An active energy ray-curable composition characterized by containing at least.
(2) The active energy ray-curable composition according to (1) above, which contains a urethane prepolymer (D) having a hydroxyl group or a carboxy group at the molecular end.
(3) The active energy ray-curable composition according to the above (1) or (2), which contains a polymerization initiator (E).
(4) A display filter comprising a pressure-sensitive adhesive layer obtained by curing a layer containing the active energy ray-curable composition according to any one of (1) to (3) above.
(5) The display filter according to (4), wherein the pressure-sensitive adhesive layer has a thickness of 50 to 2000 μm.
(6) The display filter according to the above (4) or (5), comprising a functional layer having a surface protecting function and / or an optical function.
(7) The display filter according to any one of (4) to (6), further including a conductive layer.
(8) The display which bonded this display filter to the display through the adhesive layer of the display filter as described in said (4) to (6).

  According to the present invention, there is obtained an active energy ray-curable composition having appropriate adhesion and peelability to an adherend and having a high refractive index, and this active energy ray-curable composition is used as an adhesive layer. By applying to the display filter and the display, the visibility of the display is improved, and appropriate adhesion and peelability between the display panel of the display and the display filter can be realized.

  In the present invention, the active energy ray-curable composition refers to a composition that undergoes a chemical reaction and cures when irradiated with active energy rays. Such active energy rays refer to energy rays such as ultraviolet rays, visible rays, electromagnetic waves such as infrared rays, and radiations such as electron rays, and ultraviolet rays are particularly preferable from the viewpoint of process suitability.

  The active energy ray-curable composition of the present invention comprises a urethane acrylate prepolymer (A), an acrylate monomer (B) having a carboxy group, an aromatic ring and / or an aliphatic ring, an aromatic ring and / or an aliphatic ring. It contains at least an acrylate monomer (C) having a ring and no carboxy group.

  Furthermore, the active energy ray-curable composition of the present invention contains the urethane prepolymer (D) having a hydroxyl group or a carboxy group at the molecular end in the composition containing the above (A), (B), (C). Is preferred.

  Furthermore, the active energy ray-curable composition of the present invention contains a composition containing the above (A), (B), (C), or the above (A), (B), (C), (D). It is preferable to contain a polymerization initiator (E) in the composition.

  Hereinafter, each component used for the active energy ray hardening composition of this invention is demonstrated in detail.

  The urethane acrylate prepolymer (A) according to the present invention can be obtained, for example, by acrylate-modifying the isocyanate group at the molecular end of the urethane prepolymer (f) having an isocyanate group at the molecular end.

  As the acrylate compound used for acrylate modification of the above-mentioned isocyanate group at the molecular end, an acrylate group or a methacrylate group and a functional group capable of reacting with an isocyanate group such as a hydroxyl group, a carboxyl group, an amino group, or an amide group; The compound which has is mentioned. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, butanediol mono (meth) acrylate, 2-hydroxyethyl (meth) acrylate modified with caprolactone, glycidol di (meth) acrylate, pentaerythritol Carboxyl groups such as hydroxyl group-containing (meth) acrylates such as tri (meth) acrylate, (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethyl succinic acid Containing (meth) acrylate, amino group-containing (meth) acrylate such as N, N-diethylaminoethyl (meth) acrylate, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl Meth) acrylamide, N- methylol (meth) acrylamide, N- methylol amide group-containing such as trimethylolpropane (meth) acrylamide (meth) acrylate. Among these, a hydroxyl group-containing (meth) acrylate compound is particularly preferably used.

  As the urethane prepolymer (f) having an isocyanate group at the molecular end, a commercially available product can be used, and it can be obtained by a well-established method. They can be prepared, for example, by reaction of a hydroxy-terminated polyol with a stoichiometric excess of an isocyanate compound. Examples of the polyol include polyester polyol, polyether polyol, polycaprolactone polyol, and polycarbonate polyol. Among these, polyester polyol, polyether polyol, and polycaprolactone polyol are preferable.

Hereinafter, the above polyol compound will be described in detail.
The polyester polyol is obtained by esterifying a polyvalent carboxylic acid and a polyhydric alcohol.

  The polyvalent carboxylic acid used here is not particularly limited, but adipic acid, sebacic acid, succinic acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, Examples include fumaric acid, maleic acid, maleic anhydride, itaconic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, lactic acid, dimer acid, among others, adipic acid, sebacic acid, pyromethic acid, Dimer acid is preferred.

  Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, polyethylene glycol, polybutylene glycol, polypropylene glycol, 1,4-butanediol, 1,6 -Hexanediol, 3-methyl 1,5-pentanediol, ethylene oxide or propylene oxide adduct of bisphenol A, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, etc. can be used. Bifunctional alcohols such as 4-butanediol are preferred.

  The polyether polyol is obtained by an etherification reaction of a polyhydric alcohol. As a polyhydric alcohol used here, the thing similar to the polyhydric alcohol used for manufacture of the said polyester polyol can be used.

  Polycaprolactone polyol is ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, ethylene oxide of bisphenol A, or propylene Examples thereof include oxide adducts, glycerin, trimethylolpropane, trimethylolethane, and ε-caprolactone adducts of commonly used polyhydric alcohols such as pentaerythritol.

  Polycarbonate polyol can be obtained by dehydrochlorination reaction of polyhydric alcohol and phosgene used for the synthesis of polyester polyol, or transesterification reaction of polyhydric alcohol with diethylene carbonate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, etc. Can be mentioned.

  The isocyanate compound used for the synthesis of the urethane prepolymer (f) having an isocyanate group at the molecular end includes tolylene diisocyanate, hydrogenated tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, lysine diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate. And diisocyanate compounds such as isophorone diisocyanate, xylene diisocyanate, and hydrogenated xylylene diisocyanate.

  The weight average molecular weight of the urethane acrylate prepolymer (A) used in the active energy ray-curable composition of the present invention is preferably in the range of 10,000 to 50,000, particularly preferably in the range of 20,000 to 50,000. By using the urethane acrylate prepolymer (A) having a weight average molecular weight within the above range, a cured product having good impact resistance can be obtained. If the weight average molecular weight of the urethane acrylate prepolymer (A) exceeds 50,000, the active energy ray-curable composition of the present invention tends to have a high viscosity, and workability and applicability may be inferior. In addition, when the weight average molecular weight of the prepolymer is lower than 10,000, the impact resistance and adhesion of the pressure-sensitive adhesive layer obtained by curing the layer containing the active energy ray-curable composition of the present invention may decrease. It is not preferable because there is.

  The content ratio of the urethane acrylate prepolymer (A) in 100% by mass of the active energy ray-curable composition of the present invention is preferably in the range of 20 to 95% by mass, and more preferably in the range of 30 to 90% by mass.

  In the active energy ray-curable composition of the present invention, the urethane acrylate prepolymer (A) has an elastic modulus of a cured product (a pressure-sensitive adhesive layer obtained by curing a layer containing the active energy ray-curable composition of the present invention). It can be increased to give good impact resistance.

  The active energy ray-curable composition of the present invention is preferably used as a pressure-sensitive adhesive layer for a display filter. From the viewpoint of impact resistance, it is preferable to appropriately adjust the elastic modulus according to the thickness of the pressure-sensitive adhesive layer. It is preferable to use a urethane prepolymer (D) having a hydroxyl group or a carboxy group at the molecular end in combination with the prepolymer (A). When the urethane acrylate prepolymer (A) is used alone, it may be higher than the desired elastic modulus, which may be disadvantageous for impact resistance. However, the urethane prepolymer (D) is an elastic modulus of the cured product. There is an effect of adjusting to suppress the increase of the. Further, the urethane prepolymer (D) has an effect of improving the adhesion to the adherend.

  A urethane prepolymer (D) can be contained in 10-300 mass% with respect to 100 mass% of urethane acrylate prepolymers (A). Preferably it is the range of 20-200 mass% with respect to 100 mass% of urethane acrylate prepolymers (A).

  In the urethane prepolymer (D), for example, the isocyanate group at the molecular end of the urethane prepolymer (f) having an isocyanate group at the molecular end described above is blocked with a polyvalent carboxylic acid, an oxycarboxylic acid, or a polyhydric alcohol. It is obtained by introducing a carboxy group or a hydroxyl group at the molecular end. The above polycarboxylic acid, oxycarboxylic acid, and polyhydric alcohol will be described below.

  The polyvalent carboxylic acid is not particularly limited, but adipic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, fumaric acid , Maleic acid, maleic anhydride, itaconic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, dimer acid, ethane-1,1,2-tricarboxylic acid, hexane-2,3,5 -Known and commonly used organic acids such as tricarboxylic acids are preferably used, but dicarboxylic acids are preferred from the standpoint of compatibility with other components.

  As the oxycarboxylic acid, known and commonly used organic acids such as lactic acid, glycolic acid, trioxybutyric acid, trioxyvaleric acid, trioxyhexanoic acid and gluconic acid are preferably used. These acids may be used by dissolving in a solvent or a plasticizer.

  Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, polyethylene glycol, polybutylene glycol, polypropylene glycol, 1,3-butanediol, 1,4 Polyhydric alcohols such as butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, ethylene oxide or propylene oxide adduct of bisphenol A, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, etc. It can be preferably used. Among them, diols such as 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, and 3-methyl-1,5-pentanediol are preferable from the viewpoint of compatibility with other components and water absorption stability. Particularly preferred.

  The weight average molecular weight of the urethane prepolymer (D) is preferably in the range of 10,000 to 50,000, particularly preferably in the range of 20,000 to 50,000, for the same reason as the urethane acrylate prepolymer (A) described above.

  In synthesizing the urethane acrylate prepolymer (A), the isocyanate group of the urethane prepolymer (f) can be used without modifying all the isocyanate groups at the molecular terminals of the urethane prepolymer (f) having an isocyanate group at the molecular terminals with acrylate. By modifying a part of the group with a carboxy group or a hydroxyl group, a urethane acrylate prepolymer (A) containing a urethane prepolymer (D) having a hydroxyl group or a carboxy group at the molecular end can be obtained. The urethane acrylate prepolymer (A) containing this urethane prepolymer (D) can also be preferably used as the urethane acrylate prepolymer (A) of the present invention.

  The urethane acrylate prepolymer (A) containing the urethane prepolymer (D) is composed of a urethane prepolymer (f) having an isocyanate group at the molecular terminal, an acrylate compound, a polycarboxylic acid, an oxycarboxylic acid and a polyhydric alcohol. It is obtained by reacting with at least one selected from Here, the same thing as the above-mentioned can be used for an acrylate compound, polyhydric carboxylic acid, oxycarboxylic acid, and a polyhydric alcohol.

  In the urethane acrylate prepolymer (A) containing the urethane prepolymer (D), the molecular terminal acrylate ratio is 50 to 90% of the total terminals of all the molecules of the urethane prepolymer (D) and the urethane acrylate prepolymer (A). Preferably by adjusting the charging ratio of the acrylate compound and at least one compound selected from polyvalent carboxylic acid, oxycarboxylic acid and polyhydric alcohol, or by adjusting the charging sequence and charging time. The molecular terminal acrylate ratio of all the molecules of the urethane prepolymer (D) and the urethane acrylate prepolymer (A) can be adjusted. The molecular terminal acrylate ratio is calculated from the acid value or hydroxyl value and molecular weight of the urethane acrylate prepolymer (A) containing the urethane prepolymer (D) obtained by titration or the like. Can do.

  The active energy ray-curable composition of the present invention comprises an acrylate monomer (B) (hereinafter referred to as a monomer (B)) having a carboxy group and an aromatic ring and / or an aliphatic ring, an aromatic ring and / or An acrylate monomer (C) having an aliphatic ring and not having a carboxy group (hereinafter referred to as monomer (C)) is contained. These monomers (B) and (C) can be used as reactive diluents.

  As described above, by using a monomer having a cyclic structure (aromatic ring or aliphatic ring) such as the monomer (B) and the monomer (C), the refractive index of the pressure-sensitive adhesive layer can be increased. It is known that visibility is improved when a display filter is directly attached (bonded) to the display via this adhesive layer. However, when the monomer (B) is used alone, the adhesion to the glass substrate of the display panel becomes too strong and the peelability is lowered, and the viscosity of the active energy ray curable composition becomes too high, and the base material The problem that the applicability to the resin deteriorates, and when the monomer (C) is used alone, the necessary and sufficient adhesion cannot be obtained, and the active energy ray-curable composition is irradiated with the active energy ray. As a result, it was found that polymerization shrinkage occurs when cured, and as a result, the smoothness of the surface of the cured product is impaired and the visibility and adhesion deteriorate.

  It has been found that the above problem can be solved by using the monomer (B) and the monomer (C) in combination. In particular, in order to increase the refractive index, the ratio of the monomers (B) and (C) having an aromatic ring and / or an aliphatic ring in 100% by mass of the active energy ray-curable composition is set to 10% by mass or more. In this case, the effects of the present invention can be further enjoyed.

  In the present invention, the total content ratio of the monomer (B) and the monomer (C) in 100% by mass of the active energy ray-curable composition reduces the interface reflection between the adherend such as a display panel and the pressure-sensitive adhesive layer, and is visually recognized. From the viewpoint of improving the property, 5% by mass or more is preferable, and 10% by mass or more is more preferable. On the other hand, the upper limit of the total content ratio of the monomer (B) and the monomer (C) in 100% by mass of the active energy ray-curable composition is preferably 70% by mass or less, and more preferably 50% by mass or less. When the total content ratio of the monomer (B) and the monomer (C) is greater than 70% by mass, the impact resistance of the pressure-sensitive adhesive layer obtained by curing the layer containing the active energy ray-curable composition of the present invention may be reduced. The problem that the polymerization shrinkage easily occurs and the problem that the compatibility with the urethane acrylate prepolymer (A) decreases and the liquid becomes cloudy are likely to occur.

  In the active energy ray-curable composition according to the present invention, the content ratio of the monomer (B) to the monomer (C) is a monomer in mass ratio from the viewpoint of solving the problems in the case of using each of the above monomers alone. (B): Monomer (C) = A range of 9: 1 to 1: 9 is preferable, and a range of 8: 2 to 2: 8 is more preferable.

  As the monomer (B) and the monomer (C) according to the present invention, a monofunctional or bifunctional acrylate compound can be used, but the degree of polymerization shrinkage is reduced and the hardness of the cured product does not become too high. From the viewpoint of adjusting to a monofunctional acrylate compound. In addition, the aromatic ring and the aliphatic ring in the monomer (B) and the monomer (C) are not particularly limited, but preferably have an aromatic ring and / or an aliphatic ring other than the heterocyclic ring.

  Specific examples of the monomer (B) and the monomer (C) according to the present invention are illustrated below, but the present invention is not limited thereto.

  Examples of the monomer (B) include 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl hexahydroisophthalic acid, 2- (meth) acryloyloxyethyl hexahydroterephthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl isophthalic acid, 2- (meth) acryloyloxyethyl terephthalic acid and the like are preferably used.

  Examples of the monomer (C) include phenyl (meth) acrylate, nonylphenol EO adduct (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and benzyl (meth). Acrylate, cyclohexyl (meth) acrylate, cyclononyl (meth) acrylate, cyclodecyl (meth) acrylate, cyclododecyl (meth) acrylate, cyclostearyl (meth) acrylate, cyclolauryl (meth) acrylate, 4-t-butylcyclohexyl (meth) Acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, isobornyl (meth) acrylate, phenoxy (meth) acrylate, pheno Siethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxy-polyethylene glycol (meth) acrylate, tricyclodecal (meth) acrylate, cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, bisphenol Examples include A-type ethylene oxide addition (meth) acrylate, hydro-bisphenol A-type ethylene oxide addition (meth) acrylate, and the like.

  Among the monomers (C), compounds having an aromatic ring are preferably used from the viewpoint of increasing the refractive index of the cured product. Moreover, it is also preferable to use the monomer which has a hydroxyl group like 2-hydroxy-3-phenoxypropyl (meth) acrylate as a monomer (C).

  Monomer (C) having a hydroxy group (hereinafter referred to as monomer (C2)) is a monomer (C) having no hydroxy group (hereinafter referred to as monomer (C1) in terms of adhesion, degree of polymerization shrinkage and viscosity. The monomer (C1) and the monomer (C2), the monomer (C1) having no hydroxy group and the monomer (C2) having a hydroxy group. It is preferable to use together. The content ratio (mass ratio) of the monomers (C1) and (C2) is preferably in the range of monomer (C1): monomer (C2) = 9: 1 to 3: 7, particularly 8: 2 to 5: 5. A range is preferred.

  Moreover, a monomer (C2) is preferably used also from the meaning of improving adhesiveness with the plastic film which comprises the filter for a display. Therefore, in the active energy ray-curable composition according to the present invention, by using the monomer (B) and the monomer (C1) in combination, the monomer (B) improves the adhesion to the glass substrate of the display panel, and the monomer (C1 ) Is preferable because it can improve the adhesion between the plastic film and the adhesive layer in the display filter. From the viewpoint of adhesion, the monomer (C1) has a function of adjusting so that the adhesion to the glass substrate of the display panel is not excessive. The urethane prepolymer (D) described above also contributes to adhesion, but its effect is smaller than that of the monomer (B) and monomer (C2), and in particular, the monomer for improving adhesion to the glass substrate of the display panel. (B) is essential.

  The active energy ray-curable composition according to the present invention includes polymerizable monomers other than the above-mentioned monomer (B) and monomer (C), for example, aliphatic acrylate monomers such as 2-ethylhexyl (meth) acrylate, and styrene. The vinyl monomer can be used, but the content ratio (mass ratio) of these other polymerizable monomers is 0% by mass or more with respect to 100% by mass of the total amount of the monomer (B) and the monomer (C). 20 mass% or less is preferable, and 0 mass% or more and 10 mass% or less are more preferable. In the active energy ray-curable composition of the present invention, when the content ratio of these other polymerizable monomers exceeds 20% by mass with respect to 100% by mass of the total amount of the monomer (B) and the monomer (C), the present invention. When the active energy ray-curable composition is used as an adhesive layer of a display filter intended by the present invention, improvement effects such as visibility, adhesion, and polymerization shrinkage are hindered.

  In other words, in the active energy ray-curable composition according to the present invention, the ratio of the total amount of the monomer (B) and the monomer (C) to the total amount of the polymerizable monomer containing the monomer (B) and the monomer (C) is 80 The mass% is preferably 100% by mass or less, and more preferably 90% by mass or more and 100% by mass or less.

  In addition to the above components, the active energy ray-curable composition of the present invention preferably contains a polymerization initiator (E). As the polymerizable initiator (E), commercially available products can be widely used, and the following photopolymerization initiators are preferably used. For example, acetophenone series such as diethoxyacetophenone and benzyldimethyl ketal, benzoin ether series such as benzoin and benzoin methyl ether, benzophenone series such as benzophenone and methyl o-benzoylbenzoate, and hydroxy such as 1-hydroxy-cyclohexyl-phenyl-ketone Examples include alkylphenones, thioxanthones such as 2-isopropylthioxanthone and 2,4-dimethylthioxanthone, and amines such as triethanolamine and ethyl 4-dimethylbenzoate. These polymerization initiators (E) can be used alone or in combination of two or more.

  The ratio of these polymerization initiators (E) in 100% by mass of the active energy ray-curable composition is preferably in the range of 0.05 to 10% by mass, and more preferably in the range of 0.05 to 3% by mass. If it is less than 0.05% by mass, the curability is not sufficient, and a large amount of unreacted monomer remains after photopolymerization, and bubbles may be generated at the adhesion interface. On the other hand, when the amount is more than 10% by mass, the polymerization initiator (E) may remain after the photopolymerization after the photopolymerization, thereby causing problems such as yellowing.

  If necessary, a plasticizer can be added to the active energy ray-curable composition of the present invention. Such plasticizers include benzyl benzoate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, diisodecyl phthalate, dibutyl benzyl phthalate, dioctyl phthalate Phthalic acid compounds such as butyl phthalyl butyl glycolate, diisobutyl adipate, diisononyl adipate, diisodecyl adipate, dibutoxyethyl adipate, dibutyl sebacate, di-2-ethylhexyl sebacate, etc. Sebacic acid compounds such as triethylene phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresylphenyl phosphate, dioctyl sebacate, methylacetylricinolate Any fatty acid compound, epoxy compound such as diisodecyl-4,5-epoxytetrahydrophthalate, trimellit such as tributyl trimellitic acid, tri-2-ethylhexyl trimellitic acid, tri-n-octyl trimellitic acid, triisodecyl trimellitic acid Examples include acid compounds, butyl oleate, chlorinated paraffin, polyoxypropylene glycol, polyoxytetramethylene glycol, polybutene, and polyisobutylene. However, these plasticizers need to be selected in consideration of compatibility with the urethane prepolymer.

  The content ratio of the plasticizer in 100% by mass of the active energy ray-curable composition is preferably in the range of 1 to 60% by mass.

  Furthermore, various polymerization inhibitors can be added to the active energy ray-curable composition of the present invention as necessary. As such a polymerization inhibitor, for example, hydroquinone, hydroquinone monomethyl ether, benzoquinone, pt-butylcatechol, 2,6-dibutyl-4-methylphenol and the like can be used. Moreover, various additives other than the above, for example, antioxidants, antifoaming agents, leveling agents, light stabilizers, ultraviolet absorbers, anti-coloring agents, pigments, dyes and the like can also be used as necessary.

  In the active energy ray-curable composition of the present invention, a solvent such as an organic solvent may be used for adjusting the viscosity and dispersing / dissolving a solid substance such as a polymerization initiator, but particularly an organic solvent (organic solvent). From the viewpoint of hazard to workers, fire hazard, environmental pollution, drying speed and waste of solvent, it is preferable that the addition amount is small, for example, 5 mass with respect to 100 mass% of the active energy ray curable composition. % Or less is preferable. In the present invention, the absence of solvent is particularly preferred.

  Conventionally, it is known to use an acrylic prepolymer as an active energy ray-curable composition. An acrylic prepolymer having a high molecular weight (for example, a molecular weight of 100,000 or more) is required to appropriately increase the elastic modulus of a cured product (adhesive) obtained by curing such an active energy ray-curable composition to obtain good impact resistance. Must be used. However, a high molecular weight acrylic prepolymer has a high viscosity, and an active energy ray-curable composition using the acrylic prepolymer has a high viscosity. Needs to be diluted with a relatively large amount of solvent to lower the viscosity. In order to cure by irradiating active energy rays after applying a composition containing such a solvent to a substrate, the solvent of the coating must be evaporated in advance, and a drying step for that is required, As a result, the manufacturing equipment is enlarged and the production efficiency is reduced.

  On the other hand, the urethane-based prepolymer of the present invention has a feature that a moderately highly elastic cured product can be obtained even if it has a relatively low molecular weight (10,000 to 50,000 as described above). Therefore, the viscosity of the active energy ray curable composition of the present invention using such a urethane prepolymer is higher than that of the active energy ray curable composition using the above-described high molecular weight acrylic prepolymer. Since the coating suitability can be obtained without being diluted with a solvent, the solvent drying step is substantially unnecessary. In addition, depending on the type of coating method, coating speed, coating film thickness, etc., it is expected that viscosity adjustment may be required, but even if viscosity adjustment is required, the urethane of the present invention The active energy ray-curing composition using an acrylic prepolymer can be adjusted in viscosity with a small amount of solvent compared to the conventionally known active energy ray-curing composition using an acrylic prepolymer. This is advantageous.

  The active energy ray-curable composition of the present invention described above is extremely useful as a pressure-sensitive adhesive, and has excellent visibility, impact resistance and adhesion to an adherend, and without leaving a residue of the pressure-sensitive adhesive on the adherend side. It has the property that it can be peeled off. The pressure-sensitive adhesive having these characteristics is extremely useful as a pressure-sensitive adhesive layer for directly attaching a display filter to a display panel such as a plasma display or a liquid crystal display.

  The pressure-sensitive adhesive layer obtained by curing the active energy ray-curable composition of the present invention with active energy rays may be laminated in advance as a part of a display filter, or the pressure-sensitive adhesive layer may be provided on the display panel side of the display. A layer may be bonded in advance, and a display filter may be bonded onto the pressure-sensitive adhesive layer.

  Hereinafter, a display filter having a pressure-sensitive adhesive layer (hereinafter simply referred to as a pressure-sensitive adhesive layer) obtained by curing a layer containing the active energy ray-curable composition of the present invention will be described in detail.

  Examples of the display filter of the present invention include a filter having a pressure-sensitive adhesive layer on one surface of a plastic film and a functional layer having a surface protection function and / or an optical function on the other surface. it can. The pressure-sensitive adhesive layer is preferably the outermost layer in order to attach the display filter directly to the display panel of the display. Here, the cover film and the release film for protecting the adhesive layer are not included in the configuration of the display filter because they are peeled off before or after mounting the display filter on the display panel. .

As a method of laminating or forming a pressure-sensitive adhesive layer obtained by curing a layer containing the active energy ray-curable composition of the present invention on a plastic film,
A) A method of forming a pressure-sensitive adhesive layer by irradiating and curing an active energy ray on a coating film obtained by applying an active energy ray-curable composition on a plastic film,
B) After the coating film obtained by applying the active energy ray-curable composition to another base material (for example, release PET film) is transferred to a plastic film, the active energy ray is irradiated and cured to form an adhesive layer. Method of forming,
C) A coating film obtained by applying the active energy ray-curable composition to another substrate (for example, a release PET film) is irradiated with an active energy ray and cured to form an adhesive layer, and then applied to a plastic film. A method of transferring and laminating the adhesive layer;
Can be used.

  In the present invention, among the above production methods, the methods a) and c) are preferably used.

  In the above production method, as a coating method for forming the coating film by applying the active energy curable composition of the present invention on a plastic film or another substrate, a slit die coater, a blade coater, a gravure coater, a roll coater, etc. Among them, a slit die coater that can obtain a coating film with good thickness uniformity is suitable.

  The coating film (layer containing the active energy ray-curable composition of the present invention) formed by applying the above method is cured by irradiation with active energy rays, but is photopolymerized using ultraviolet rays as active energy rays. In the case of curing by using an inert gas such as nitrogen gas, the curing is preferably carried out in an oxygen-free atmosphere, or in a state where it is shielded from air by coating with an ultraviolet transparent film. In the case of curing by irradiation with an electron beam, a known electron beam irradiation apparatus can be used.

  When ultraviolet rays or electron beams are used as the active energy rays, the amount of irradiation is preferably 100 to 3000 mJ, more preferably 100 to 1000 mJ in terms of integrated light quantity. When the irradiation amount is less than 100 mJ, curing may be insufficient, and when it is more than 3000 mJ, workability may be inferior, and the substrate may be deformed or damaged by heat during irradiation.

  The pressure-sensitive adhesive layer obtained as described above preferably has an elastic modulus in the range of 0.03 to 1.0 MPa and a durometer hardness in the range of E1 / 15 to E30 / 15 from the viewpoint of impact resistance. .

  From the viewpoint of obtaining good impact resistance, the thickness of the pressure-sensitive adhesive layer is preferably 50 μm or more, more preferably 75 μm or more, and particularly preferably 100 μm or more. The upper limit of the thickness is preferably 2000 μm or less, more preferably 1000 μm or less, and particularly preferably 500 μm or less in consideration of productivity such as application suitability of the active energy ray-curable composition and curing rate. Moreover, since visibility will fall when the thickness of an adhesive layer becomes large, it is preferable not to make it larger than the thickness of 2000 micrometers which is said upper limit.

  As the plastic film constituting the display filter of the present invention, a film made of a resin as shown below can be used. Examples of such resins include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose resins such as triacetyl cellulose, polyolefin resins such as polyethylene, polypropylene, and polybutylene, acrylic resins, polycarbonate resins, arton resins, epoxy resins, polyimide resins, poly Examples include ether imide resins, polyamide resins, polysulfone resins, polyphenylene sulfide resins, and polyether sulfone resins. Among these, a polyester resin, a polyolefin resin, and a cellulose resin are preferable, and a polyester resin is particularly preferably used.

  The thickness of the plastic film is suitably in the range of 50 to 300 μm, but is particularly preferably in the range of 80 to 250 μm from the viewpoint of cost and ensuring the rigidity of the display filter.

  The plastic film used in the present invention is preferably provided with an undercoat layer (primer layer) for enhancing the adhesiveness (adhesive strength) with the pressure-sensitive adhesive layer or the functional layer described later.

  The display filter of the present invention is preferably provided with a functional layer having a surface protection function and / or an optical function on the surface opposite to the surface on which the pressure-sensitive adhesive layer is formed with respect to the plastic film. Examples of the functional layer having such a surface protecting function include a hard coat layer and an antifouling layer, and examples of the functional layer having an optical function include an antireflection layer and an antiglare layer. The functional layer may be composed of a single layer or a plurality of layers. When the functional layer is composed of a single layer, the plurality of functions described above may be imparted to one layer. Alternatively, a plurality of different functional layers can be stacked. Each functional layer will be described in detail below.

  The hard coat layer which is one of the functional layers having a surface protection function is a layer provided for preventing scratches. The hard coat layer preferably has high hardness, and the surface hardness of the hard coat layer can be expressed by pencil hardness defined by JIS K5600-5-4 (1999), and the surface on the side where the hard coat layer is provided. The pencil hardness can be evaluated by scratching the surface of another functional layer (if another functional layer is provided on the hard coat layer) directly with a pencil. In the present invention, the pencil hardness of the surface on which the hard coat layer is provided is preferably 1H to 9H, and more preferably 2H to 9H.

  For the hard coat layer, acrylic resin, urethane resin, melamine resin, epoxy resin, organic silicate compound, silicone resin, or the like can be used. In particular, silicone resins and acrylic resins are preferable in terms of hardness and durability. Further, in terms of curability, flexibility, and productivity, those made of an active energy ray-curable acrylic resin or a thermosetting acrylic resin are preferable.

  As for the thickness of a hard-coat layer, 0.1-20 micrometers is preferable, More preferably, it is 1-10 micrometers. When the thickness of the hard coat layer is less than 0.1 μm, even if it is sufficiently cured, it is too thin, so that the surface hardness is not sufficient and it tends to be easily scratched. On the other hand, when the thickness of the hard coat layer exceeds 20 μm, the cured film tends to be cracked due to stress such as bending.

  The hard coat layer can be given a function as a high refractive index layer constituting an antireflection layer described later. The refractive index of the hard coat layer can be increased by adding ultrafine particles of a metal or metal oxide having a high refractive index.

  The antifouling layer, which is one of the functional layers that have a surface protection function, prevents or adheres to the adhesion of greasy substances and dirt and dust from the environment when people touch the surface of the display filter. Is a layer for facilitating removal. As the antifouling layer, for example, a fluorine coating agent, a silicon coating agent, a silicon / fluorine coating agent, or the like is used. The thickness of the antifouling layer is preferably in the range of 1 to 10 nm.

  The antireflection layer, which is one of the functional layers having an optical function, prevents reflection or reflection of external light such as a fluorescent lamp that affects the image display of the display. The antireflection layer preferably has a surface luminous reflectance of 5% or less, more preferably 4% or less, and particularly preferably 3% or less. The luminous reflectance has no particular lower limit, and is most preferably 0%, but the luminous reflectance is about 0.05%. Here, the luminous reflectance is a luminous reflectance (Y) calculated according to the CIE1931 system by measuring the reflectance in the visible region wavelength (380 to 780 nm) using a spectrophotometer or the like.

As such an antireflection layer, it is preferable to use a layer in which two or more layers of a high refractive index layer and a low refractive index layer are laminated so that the low refractive index layer is on the viewing side. The refractive index of the high refractive index layer is preferably in the range of 1.5 to 1.7, particularly preferably in the range of 1.55 to 1.69. The refractive index of the low refractive index layer is preferably in the range of 1.25 to 1.49, particularly preferably in the range of 1.3 to 1.45.
Materials for forming the high refractive index layer include those obtained by polymerizing and curing urethane (meth) acrylate, polyester (meth) acrylate, etc., or those obtained by crosslinking and curing a silicone-based, melamine-based, or epoxy-based crosslinkable resin material. And organic materials such as those containing indium oxide as a main component and containing a small amount of titanium dioxide or the like, or inorganic materials such as Al ₂ O ₃ , MgO, and TiO ₂ . Among these, organic materials are preferably used.
The thickness of the high refractive index layer is preferably in the range of 0.01 to 20 μm, and more preferably in the range of 0.05 to 10 μm.

The low refractive index layer constituting the antireflection layer is composed of a fluorine-containing polymer, a (meth) acrylic acid partial or fully fluorinated alkyl ester, an organic material such as fluorine-containing silicone, and an inorganic material such as MgF ₂ , CaF ₂ , and SiO _2. It can be composed of a system material. The thickness of the low refractive index layer is preferably in the range of 0.01 to 1 μm, and more preferably in the range of 0.02 to 0.5 μm.

  The antiglare layer, which is one of the functional layers having an optical function, prevents glare in an image, and a film having minute irregularities on the surface is preferably used. As the antiglare layer, for example, particles are dispersed in a thermosetting resin or a photocurable resin and applied and cured on a support, or a thermosetting resin or a photocurable resin is applied to the surface. For example, a mold having a desired surface state and pressed to form an unevenness and then cured can be used. The antiglare layer preferably has a haze value (JIS K 7136: 2000) of 0.5 to 20%. The thickness of the antiglare layer is preferably from 0.01 to 20 μm.

  The antireflection function and the antiglare function described above may be provided as independent layers, or may be provided as a layer having both functions.

As described above, the functional layer may be a single layer or a plurality of layers. In the case of a single layer, it is preferable to have a plurality of functions. The following is an example of a single layer having a plurality of functions.
a) Anti-reflective hard coat layer b) Anti-glare hard coat layer c) Anti-glare anti-reflective layer It is also preferable that the functional layer is composed of a plurality of layers. In the following plural configurations, the layers described on the right side are arranged on the viewing side (the layers described on the left side are arranged on the display panel side).
d) hard coat layer / high refractive index layer / low refractive index layer e) high refractive index hard coat layer / low refractive index layer f) hard coat layer / antiglare layer g) hard coat layer / antiglare antireflection layer h ) Hard coat layer / antifouling layer i) Hard coat layer / high refractive index layer / low refractive index layer / antifouling layer j) Antiglare hard coat layer / antifouling layer k) Antireflection hard coat layer / antifouling Layer The display filter of the present invention can be provided with a conductive layer (electromagnetic wave shielding layer), a near-infrared shielding layer, a color tone adjusting layer, and the like in addition to the functional layer described above. These layers are preferably provided between the pressure-sensitive adhesive layer of the present invention and the functional layer described above. Moreover, the near-infrared shielding layer and the color tone adjusting layer can be omitted by providing the pressure-sensitive adhesive layer or the functional layer with a near-infrared shielding function and a color tone adjusting function.

  In addition, when providing a conductive layer (electromagnetic wave shielding layer), a near-infrared shielding layer, a color tone adjustment layer, etc., a film in which these layers are provided in another plastic film and a plastic film in which the above-described functional layer is provided are different from each other. Adhesive layer (As another adhesive layer, there is no problem even if an adhesive layer obtained by curing the active energy ray-curable composition of the present invention is used, or any other adhesive layer is used. It is also possible to use a so-called two-sheet display filter that is bonded via a via. Even in the case of such a two-sheet configuration, the pressure-sensitive adhesive layer obtained by curing the active energy ray-curable composition of the present invention is arranged to be one outermost layer of the display filter, and the functional layer is the other outermost layer. It is arranged to become. A typical configuration of the above two-panel display filter is shown below.

<Adhesive layer of the present invention / plastic film 1 / conductive layer / another adhesive layer / near infrared shielding layer / plastic film 2 / functional layer>
In the above configuration, the color tone adjusting function can be imparted to the near-infrared shielding layer, another pressure-sensitive adhesive layer, or the pressure-sensitive adhesive layer of the present invention. It can be omitted by imparting a near-infrared shielding function to the pressure-sensitive adhesive layer or functional layer of the invention. When a mesh-like conductive layer made of a metal foil such as a copper foil by a photolithography / etching method is used as the conductive layer, an adhesive layer may be interposed between the plastic film 1 and the conductive layer.

  As the display filter according to the present invention, a so-called mono film filter including only one plastic film is preferable in terms of material cost and production cost. A typical configuration of such a mono film filter is exemplified below.

a): Adhesive layer / near-infrared shielding layer / plastic film / conductive layer / functional layer of the present invention b): Adhesive layer / conductive layer / plastic film / functional layer of the present invention In the configuration of a) above, color tone adjustment The function can be imparted to the near-infrared shielding layer or the pressure-sensitive adhesive layer of the present invention, and the near-infrared shielding layer can be omitted by imparting a near-infrared shielding function to the pressure-sensitive adhesive layer or functional layer of the present invention. it can. Similarly, in the configuration of b), a color tone adjusting function can be imparted to the pressure-sensitive adhesive layer of the present invention, and a near-infrared shielding function can be imparted to the pressure-sensitive adhesive layer or functional layer of the present invention. In addition, as described above, when using a mesh-like conductive layer made of a metal foil such as copper foil by a photolithographic etching method, an adhesive layer is interposed between the plastic film and the conductive layer. May be.

  Below, a conductive layer, a near-infrared shielding layer, and a color tone adjustment layer are demonstrated in detail.

  The conductive layer is a layer for shielding electromagnetic waves generated from the display. The surface resistance value of the conductive layer is preferably lower, preferably 10Ω / □ or less, more preferably 5Ω / □ or less, and particularly preferably 3Ω / □ or less. The lower limit of the sheet resistance value is about 0.01Ω / □. The sheet resistance value of the conductive layer can be measured by a four-terminal method. As the conductive layer, a conductive thin film or a conductive mesh is used.

  As the conductive thin film, a metal thin film, an oxide semiconductor film, a laminate thereof, or the like can be used. As a material for the metal thin film, silver, gold, palladium, copper, indium, tin, or an alloy of silver and other metals is used. As a method for forming the metal thin film, a known method such as sputtering, ion plating, vacuum deposition, or plating can be used. As a material of the oxide semiconductor film, oxides such as zinc, titanium, indium, tin, zirconium, bismuth, antimony, tantalum, cerium, neodymium, lanthanum, thorium, magnesium, gallium, sulfides, or a mixture of these oxides Etc. are used. As a method for forming the oxide semiconductor, a known method such as sputtering, ion plating, ion beam assist, vacuum deposition, or wet coating can be used.

  As the conductive layer used in the present invention, a conductive mesh is preferable. The conductive mesh has an advantage that a low sheet resistance value can be obtained as compared with the metal thin film.

  As one method for obtaining a conductive mesh, a metal film laminated film in which a metal film such as copper foil is bonded to a plastic film via an adhesive is etched using a photolithographic method, a screen printing method, or the like. There is a method of etching a metal film after forming a pattern.

  The photolithographic method is a method in which a metal layer of a metal film laminated film is provided with a photosensitive layer that is exposed by irradiation with ultraviolet rays, etc., and this photosensitive layer is exposed imagewise using a photomask or the like and developed to form a resist image. is there.

  The screen printing method is a method of forming a resist image by pattern-printing an etching resist ink on the metal film surface of the metal film laminated film and curing it.

  Etching methods include chemical etching methods. Chemical etching is a method in which unnecessary conductors other than the conductor part protected by an etching resist are dissolved and removed with an etching solution. Examples of the etching solution include a ferric chloride aqueous solution, a cupric chloride aqueous solution, and an alkaline etching solution.

  Other methods for obtaining a conductive mesh include 1) a method of etching a metal thin film (a metal thin film formed by a method other than laminating the above metal foil), and 2) a mesh pattern formed directly by printing. 3) a method using a photosensitive silver salt, 4) a method of developing after laminating a metal film on a printed pattern, and 5) a method of laser ablating a metal thin film. Each method will be described in detail below.

  In the method 1), a metal thin film is formed on a plastic film without using an adhesive layer or an adhesive layer, and an etching resist pattern is formed on the metal thin film by using a photolithographic method or a screen printing method. In this method, the metal thin film is etched after the production. The metal thin film is formed by a known method such as sputtering, ion plating, vacuum deposition, or plating of metal (for example, silver, gold, palladium, copper, indium, tin, or an alloy of silver and other metals). Can be used.

  As the method 2), there are a method of printing a conductive paste or the like on a plastic film in a mesh pattern, and a method of printing a mesh pattern on a plastic film with a catalyst ink or the like and applying a metal plating thereto. As one of the latter methods, a mesh ink pattern is printed using a catalyst ink made of a palladium colloid-containing paste, and this is immersed in an electroless copper plating solution to perform electroless copper plating, followed by electrolytic copper plating. Furthermore, there is a method of forming a conductive mesh pattern by performing electrolytic plating of a Ni—Sn alloy.

  The above method 3) is a method in which a silver salt emulsion layer such as silver halide is coated on a plastic film, and after photomask exposure or laser exposure, development processing is performed to form a silver mesh. The formed silver mesh is preferably further plated with a metal such as copper or nickel. This method is described in International Publication No. 04/7810 pamphlet, Japanese Patent Application Laid-Open No. 2004-221564, Japanese Patent Application Laid-Open No. 2006-12935, and the like, and can be referred to.

  In the above method 4), a reversible resin is printed on the plastic film and a reverse pattern to the mesh pattern is printed. A metal thin film is formed on the printed pattern by the same method as in 1) above, and then developed. In this method, the resin and the metal film thereon are peeled to form a metal mesh pattern. As the peelable resin, a resin or resist that is soluble in water, an organic solvent, or an alkali can be used. This method is described in JP 2001-185834 A, JP 2001-332889 A, JP 2003-243881, JP 2006-140346 A, JP 2006-156642 A, and the like. You can refer to it.

  The method 5) is a method for producing a metal mesh by a laser ablation method from a metal thin film formed on a plastic film by the same method as 1). Laser ablation means that when a solid surface that absorbs laser light is irradiated with laser light with a high energy density, the bonds between the irradiated parts are broken and evaporated, causing the solid surface of the irradiated part to break. It is a phenomenon that is cut away. By utilizing this phenomenon, the solid surface can be processed. Since laser light is highly straight and condensing, it is possible to selectively process a fine area about three times the wavelength of the laser light used for ablation, and high processing accuracy is obtained by the laser ablation method. I can do it.

  The laser used for such ablation can be any laser having a wavelength that is absorbed by the metal. For example, a gas laser, a semiconductor laser, an excimer laser, or a solid laser using a semiconductor laser as an excitation light source can be used. Further, a second harmonic light source (SHG), a third harmonic light source (THG), or a fourth harmonic light source (FHG) obtained by combining these solid-state lasers and a nonlinear optical crystal can be used.

  Among such solid-state lasers, an ultraviolet laser having a wavelength of 254 nm to 533 nm is preferably used from the viewpoint of not processing a plastic film. Among them, it is preferable to use a solid laser SHG (wavelength 533 nm) such as Nd: YAG (neodymium: yttrium, aluminum, garnet), and more preferably a solid laser THG (wavelength 355 nm) ultraviolet laser such as Nd: YAG. .

  As a laser oscillation method, any type of laser can be used. From the viewpoint of processing accuracy, a pulse laser is preferably used, and a Q-switch type pulse laser having a pulse width of ns or less is more preferable.

  In the case of this method, it is preferable that a metal oxide layer of 0.01 to 0.1 μm is further formed on the metal thin film (viewing side), and then the metal thin film and the metal oxide layer are laser ablated. As the metal oxide, metal oxides such as copper, aluminum, nickel, iron, gold, silver, stainless steel, chromium, titanium, and tin can be used. However, copper oxide is used from the viewpoint of price and film stability. preferable. As a method for forming the metal oxide, a vacuum deposition method, a sputtering method, an ion plate method, a chemical vapor deposition method, an electroless method, an electrolytic plating method, or the like can be used.

  Examples of the mesh pattern of the conductive mesh that can be used in the present invention include a lattice pattern, a pentagonal or more polygonal pattern, a circular pattern, or a composite pattern thereof, and a random pattern is also preferably used. The line width and line interval (pitch) of the mesh are preferably designed so that the aperture ratio is 70% or more and 98% or less, the line width is preferably 5 to 40 μm, and the line interval (pitch) is 100 to 500 μm. The range of is preferable. The thickness of the conductive layer is suitably in the range of 0.1 to 20 μm.

  In the present invention, the conductive mesh is preferably blackened. The blackening treatment can be performed by oxidation treatment or black printing. For example, methods described in JP-A-10-41682, JP-A-2000-9484, JP-A-2005-317703, etc. can be used. The blackening treatment is preferably performed on at least the surface and both side surfaces of the conductive mesh. Further, it is preferable to perform blackening treatment on both sides and both side surfaces of the conductive mesh.

  In order to efficiently produce a laminate including an adhesive layer, a plastic film, a functional layer, and a conductive layer used for a display filter on a continuous production line, the conductive layer is preferably a continuous mesh. A continuous mesh is a mesh pattern that is formed without interruption. For example, when a laminate having at least a conductive layer is produced in the form of a long roll, the mesh is continuously formed in the winding direction of the roll. It is that. By using such a continuous mesh, when the laminate roll is cut to manufacture a sheet-like display filter, the yield and productivity are improved. In addition, continuous mesh can be easily applied to various sizes of displays, and if defects occur in the manufacturing process of display filters, only a limited amount of waste can be discarded. There are advantages.

  The near-infrared shielding layer is a layer that shields near-infrared rays generated from the display. The near-infrared shielding layer is preferably adjusted so that the maximum value of light transmittance in the wavelength range of 800 to 1100 nm is 30% or less, more preferably 15% or less. When providing the near-infrared shielding layer as an independent layer, it can be formed by applying and drying a paint in which a near-infrared absorber is dispersed or dissolved in a resin binder. Moreover, a near-infrared shielding function can be provided to these layers by containing a near-infrared absorber in an adhesive layer or a functional layer. As a near-infrared absorber, known organic absorbers such as phthalocyanine compounds, anthraquinone compounds, dithiol compounds, diimonium compounds, or tungsten oxide fine particles or composite tungsten oxides described in JP-A No. 2006-154516 Known inorganic absorbents such as fine particles can be used.

  The color tone adjustment layer is a layer for absorbing light of a specific wavelength emitted from the display to improve color purity and whiteness. In particular, it is preferable to shield orange light that reduces the color purity of red light emission, and it is preferable to include a dye having an absorption maximum in a wavelength range of 580 to 620 nm. Furthermore, it is preferable to contain a dye having an absorption maximum at a wavelength of 480 to 500 nm in order to improve whiteness. The color tone adjusting function may be provided by newly providing a layer containing a dye that absorbs light of the above-described wavelength, or may be imparted by adding a dye to the above-described near infrared shielding layer or pressure-sensitive adhesive layer.

  Examples will be specifically described below, but the present invention is not limited to these examples.

  The molecular weight and the acrylate terminal ratio of the urethane acrylate prepolymer and urethane prepolymer synthesized below were measured as follows.

<Measurement of molecular weight>
The weight average molecular weight and number average molecular weight were measured by GPC. For measurement, WALTERS GPC-150CPplus (manufactured by Japan WALTERS) was used under the following conditions.

Detector: WALTERS 2410
Solvent: Tetrahydrofuran Column: 2 HR4, 1 HR4E (7.5 mm x 300 mm)
Temperature: 40 ° C
Concentration: 0.2%
Injection volume: 100 μl
Flow velocity: 1.0m / m
n number: 3
<Measurement of acrylate end ratio>
Based on JISK-1557, the hydroxyl value was calculated by dissolving the resin in chloroform, adding acetic anhydride and titrating with KOH. The acrylate terminal ratio was calculated from the hydroxyl value and the weight average molecular weight.

<Synthesis of urethane prepolymer (f) having an isocyanate group at the molecular end>)
In a flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube, “EXENOL 3020” [polypropylene glycol (number average molecular weight 3200) manufactured by Asahi Glass Urethane Co., Ltd.] 97.98 parts by mass, dilauric acid 0.11 part by mass of dibutyltin was charged.

  Next, the temperature inside the system was raised to 70 ° C. while blowing nitrogen gas, and after uniformly dissolving, 8.65 parts by mass of isophorone diisocyanate was added, and the temperature was kept stirring for 3 hours. As a result of GPC measurement every 30 minutes, The ratio Mw / Mn between the weight average molecular weight (Mw) and the number average molecular weight (Mn) was confirmed to be constant at 1.5, and the reaction was terminated to obtain a urethane prepolymer (f) having an isocyanate group at the molecular end. It was.

<Synthesis of urethane acrylate prepolymer (A1)>
200 parts by mass of the above urethane prepolymer (f) was charged into a flask equipped with a stirrer, thermometer, reflux condenser and nitrogen introduction tube, and then the temperature in the system was raised to 80 ° C. to give 2-hydroxyethyl acrylate 3 .69 parts by mass and 0.22 parts by mass of hydroquinone monomethyl ether were added, and the mixture was kept warm (80 ° C.) with stirring, and the reaction was terminated after confirming that the isocyanate group had completely disappeared by IR measurement. (A1) (weight average molecular weight 24000) was obtained.

<Synthesis of urethane acrylate prepolymer (A2)>
200 parts by mass of the urethane prepolymer (f) above was charged into a flask equipped with a stirrer, thermometer, reflux condenser and nitrogen introduction tube, and then the system was heated to 80 ° C., and nitrogen gas and oxygen gas were added. While blowing, 2.56 parts by mass of 2-hydroxyethyl acrylate and 0.84 parts by mass of 1,3-butanediol were added, and the mixture was kept warm (80 ° C.) with stirring, and the isocyanate group completely disappeared by IR measurement. After confirming and terminating the reaction, urethane acrylate prepolymer A2 (weight average molecular weight 24000) was obtained. The urethane acrylate prepolymer (A2) thus obtained is a prepolymer containing a urethane prepolymer having a hydroxyl group at the molecular end and a urethane acrylate prepolymer. The acrylate terminal ratio of this prepolymer was 70%.

<Synthesis of urethane prepolymer (D)>
200 parts by mass of the above urethane prepolymer (f) was charged into a flask equipped with a stirrer, thermometer, reflux condenser and nitrogen introduction tube, and then the system was heated to 70 ° C., and nitrogen gas was blown into the flask. Then, 2.6 parts by mass of 3-butanediol was added, and the mixture was kept warm (70 ° C.) with stirring, and the reaction was terminated after confirming that the isocyanate group had completely disappeared by IR measurement. The urethane prepolymer (D) (Weight average molecular weight 24000) was obtained.
Example 1
<Preparation of active energy ray-curable composition>
75 parts by mass of urethane acrylate prepolymer (A1), 10 parts by mass of 2-acryloyloxyethyl hexahydrophthalic acid as monomer (B), 10 parts by mass of phenoxyethyl acrylate as monomer (C1), phosphoric acid as plasticizer Activated by adding 5 parts by mass of tricresyl (hereinafter referred to as TCP) and 1 part by mass of a hydroxyalkylphenone photopolymerization initiator (Ciba Geigy, Irgacure 184, hereinafter referred to as IC184) as a polymerization initiator and mixing them uniformly. An energy ray curable composition was prepared.

<Preparation of adhesive layer>
The above active energy ray-curable composition was applied onto a release PET film with a slot die coater and then irradiated with 1000 mJ of accumulated light using a high pressure mercury lamp to form an adhesive layer. The thickness of the obtained pressure-sensitive adhesive layer was 200 μm.

<Preparation of display filter>
A filter having a near-infrared shielding layer, a plastic film (PET film), a conductive layer, and a functional layer in this order was prepared as follows, and the pressure-sensitive adhesive layer prepared above was laminated on the near-infrared shielding layer. 1 display filter was obtained.

<Formation of conductive layer>
A palladium colloid-containing paste was printed on a PET film having a thickness of 100 μm (Lumirror (registered trademark) U34 manufactured by Toray Industries, Inc.) using a screen having a grid-like mesh pattern with a line width of 30 μm and a line interval of 250 μm. It was immersed in a copper plating solution, subjected to electroless copper plating, subsequently subjected to electrolytic copper plating, and further subjected to electrolytic plating of a Ni—Sn alloy to form a mesh-like conductive layer having a thickness of 5 μm.

<Functional layer coating formation>
The following hard coat layer, high refractive index layer, and low refractive index layer were sequentially coated on the conductive layer of the PET film on which the conductive layer was formed.

<Hard coat layer>
A coating obtained by diluting a commercially available hard coating agent (“Desolite Z7528” manufactured by JSR) with isopropyl alcohol to a solid content concentration of 30% is applied with a micro gravure coater, dried at 80 ° C., and then irradiated with ultraviolet rays of 1.0 J / cm ² . Irradiated and cured to provide a 10 μm thick hard coat layer.

<High refractive index layer>
A mixture of 6 parts by mass of tin-containing indium oxide particles (ITO), 2 parts by mass of polyfunctional acrylate, 18 parts by mass of methanol, 54 parts by mass of polypropylene glycol monoethyl ether, and 20 parts by mass of isopropyl alcohol was stirred to give a coating film refractive index of 1. A 67 high refractive index paint was prepared.

This paint is applied onto the hard coat layer using a micro gravure coater, dried, and then irradiated with ultraviolet rays of 1.0 J / cm ² to cure the applied layer, and a high refractive index layer having a thickness of about 0.1 μm. Formed.

<Low refractive index layer>
A silica slurry comprising 144 parts by mass of hollow silica particles having an outer shell with a primary particle diameter of 50 nm (porosity 40%) and 560 parts by mass of isopropyl alcohol was prepared, 219 parts by mass of methyltrimethoxysilane, 3,3,3-tri 158 parts by mass of fluoropropyltrimethoxysilane, 704 parts by mass of the above silica slurry, and 713 parts by mass of polypropylene glycol monoethyl ether are mixed with stirring, 1 part by mass of phosphoric acid and 130 parts by mass of water are mixed, and the mixture is stirred at 30 ° C. ± 10 ° C. Then, the mixture was hydrolyzed for 60 minutes, and the temperature was raised to 80 ° C. ± 5 ° C., followed by polymerization while stirring for 60 minutes to obtain a silica particle-containing polymer.

  Next, 1200 parts by mass of this silica particle-containing polymer and 5244 parts by mass of isopropyl alcohol were stirred and mixed, then 15 parts by mass of acetoxyaluminum as a curing catalyst was added and stirred again to prepare a paint having a refractive index of 1.35. . This paint was applied onto the high refractive index layer with a small diameter gravure coater, dried and cured to form a low refractive index layer having a thickness of about 0.1 μm.

<Lamination of near-infrared shielding layer>
On the opposite side of the conductive layer of the PET film in which the conductive layer and the functional layer are laminated, a near-infrared shielding layer having an orange light shielding function (1.5 parts by mass of a phthalocyanine dye as a near-infrared absorbing dye and a diimonium series) A layer in which 2.5 parts by mass of a dye and 0.5 parts by mass of a tetraazaporphyrin-based dye as an orange light-absorbing dye are mixed with 100 parts by mass of an acrylic resin so that the dry film thickness is 12 μm. ).
(Examples 2-6 and Comparative Examples 1-3)
Each display filter was produced in the same manner as in Example 1 except that the active energy ray-curable composition prepared at the component ratio shown in Table 1 below was used.

  In addition, the monomer (C2) in Table 1 is 2-hydroxy-3-phenoxypropyl acrylate.

  About the adhesive layer of the Example obtained by making it above, and the filter for a display, visibility, adhesiveness, peelability, and the smoothness of the adhesive layer were evaluated.

<Visibility>
A display filter was attached to the display panel of the plasma display, and the contrast of the image was visually evaluated.

<Adhesion and peelability>
A filter for a display was attached to the display panel of the plasma display, and the strength of the filter was checked.

<Smoothness>
The surface of the pressure-sensitive adhesive layer obtained by applying and curing the active energy ray-curable composition was visually observed to evaluate the smoothness.

The result evaluated as mentioned above about an Example and a comparative example is shown below.
In all of the examples of the present invention, the adhesion to the display panel was good, and the display filter could be peeled off from the display panel without any problem.

  In all of the examples of the present invention, the image contrast was improved as compared with Comparative Example 3 in which the comparative monomer (2-ethylhexyl acrylate) was used alone.

  Furthermore, in all of the examples of the present invention, the polymerization shrinkage was small, and the smoothness of the pressure-sensitive adhesive layer surface was good.

  On the other hand, Comparative Example 1 using the monomer (B) alone was too strong to peel off and required a lot of labor to peel off, and even if peeled off, the adhesive remained on the display panel. .

  Further, in Comparative Example 2 in which the monomer (C1) was used alone, polymerization shrinkage occurred and undulation was generated on the surface of the pressure-sensitive adhesive layer, and a good smooth surface could not be obtained.

  In Comparative Examples 2 and 3, the adhesion to the display panel was low, and the display filter peeled off the display panel with a little force.

  Further, among the examples of the present invention, Examples 3 and 4 using the urethane acrylate prepolymer (A1) and the urethane prepolymer (D), and Examples 5 and 6 using the urethane acrylate prepolymer (A2) are as follows: Compared with Example 1 using a urethane acrylate prepolymer (A1), the impact resistance by the steel ball drop test shown below was improved.

In all of Examples 3 to 6, the drop height increased by 2 to 5 cm compared to Example 1.
<Steel ball drop test>
The filter for display of each Example was bonded on soda glass with a thickness of 1.3 mm, and the glass ball was broken by dropping a steel ball having a diameter of 38 mm and a mass of 229 g while changing the height from above vertically. The fall height at the time was calculated.

  The higher the drop height when the glass is broken, the better the impact resistance.

Claims (8)

Urethane acrylate prepolymer (A);
An acrylate monomer (B) having a carboxy group and an aromatic ring and / or an aliphatic ring;
An acrylate monomer (C) having an aromatic ring and / or an aliphatic ring and having no carboxy group,
An active energy ray-curable composition characterized by containing at least.   The active energy ray hardening composition of Claim 1 containing the urethane prepolymer (D) which has a hydroxyl group or a carboxy group at the molecular terminal.   The active energy ray hardening composition of Claim 1 or 2 containing a polymerization initiator (E).   A display filter comprising a pressure-sensitive adhesive layer obtained by curing a layer containing the active energy ray-curable composition according to claim 1.   The display filter according to claim 4, wherein the pressure-sensitive adhesive layer has a thickness of 50 to 2000 μm.   6. The display filter according to claim 4, further comprising a functional layer having a surface protection function and / or an optical function.   The display filter according to any one of claims 4 to 6, comprising a conductive layer.   The display which bonded this display filter to the display through the adhesive layer of the display filter of Claim 4-6.