JP2007009116A - Optical resin composition, optical resin sheet produced by using the same, optical filter for plasma display and plasma display obtained by using the composition, etc. - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin material having transparency, moderate adhesiveness, excellent moisture-resistant reliability and sufficient shock-absorbing property contributing to the protection of a display such as a plasma display. <P>SOLUTION: The optical resin composition comprises 15-60 pts.wt. of a copolymer of a 4-18C alkyl acrylate and a hydroxyalkyl acrylate, 39-84 pts.wt. of a monomer mixture having a composition similar to that of the copolymer, 0.5-10 pts.wt. of a monomer having ≥2 acryloyl groups, and 0.3-3 pts.wt. of a photopolymerization initiator. The invention further provides a resin sheet for optical use composed of the resin composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical resin composition useful for prevention of cracking of a display device such as a liquid crystal display panel and a plasma display panel (PDP), relaxation of stress and impact, an optical resin sheet using the same, and a plasma using the same. The present invention relates to an optical filter for display and a plasma display panel.

Glass cathode ray tubes (CRTs) are determined to be anti-scattering and not penetrated by an impact resistance test by dropping a steel ball in accordance with UL standards or radio wave control methods for televisions and displays.
Therefore, in order to satisfy this standard, it is necessary to design the CRT glass to be thick, and the weight of the CRT is increased. Then, the method of laminating | stacking the synthetic resin protective film which has a self-restoration property on glass as a means to give scattering prevention property without making glass thick is proposed (refer patent document 1 and patent document 2). However, although this proposal is characterized by anti-scattering properties, it does not have a function of preventing glass from breaking.
On the other hand, in order to prevent cracking of the PDP, a flat panel display (FPD) is provided with a space of about 1 to 5 mm from the PDP, and a front plate made of glass or the like having a thickness of about 3 mm on the front (viewing). On the surface side). For this reason, as the PDP is increased in size, the area of the front plate is also increased, which increases the weight of the PDP.

  Therefore, in order to prevent cracking of the display, it has been proposed to laminate a specific resin on the display surface or to laminate an optical filter on which the specific resin is laminated (Patent Documents 3, 4, and 5). reference)

Japanese Patent Laid-Open No. 06-333515 Japanese Patent Laid-Open No. 06-333517 JP 2004-58376 A JP 2005-107199 A JP 2004-263084 A

In Patent Documents 3 and 4, there is no particular consideration regarding the composition of the resin material to be used, and the means for expressing adhesiveness and transparency is unclear. In particular, in Patent Document 3, there is no consideration regarding the moisture resistance reliability of the resin, and the resin material having the composition specifically shown in the examples becomes cloudy in a short time moisture resistance test after being applied to a display. Also in Patent Document 4, acrylic acid is used as a part of the resin specifically shown in the examples, and the resin becomes cloudy in a long-time moisture resistance test, and is in contact with the metal during the moisture resistance test. This causes the problem of corroding. Further, in Patent Documents 3 and 4, it is considered that the examination is insufficient from the viewpoint of obtaining better shock absorption. In Patent Document 4, the thickness of the impact-resistant layer using a resin is set to 0.2 to 1 mm, but there is no disclosure from the viewpoint of increasing the thickness to further improve the shock absorption. Patent Document 5 discusses heat and humidity resistance, but the resin material composition described in this patent document cannot be expected to significantly improve impact resistance. Moreover, the thickness of the resin layer in an Example is 1 mm, and it is thought that examination is inadequate from a viewpoint of obtaining the more outstanding impact absorbability. In addition, as described in the example of Patent Document 5, if a soft resin after curing is used thickly, the surface hardness of the front filter is lowered, which may cause a problem in scratch resistance. Conceivable.
Therefore, the present invention is an optical resin composition that is transparent, has excellent moderate adhesive strength and moisture resistance reliability, has an impact absorption property that contributes to protection of a display, an optical resin sheet using the same, and these. An object is to provide an optical filter for plasma display. Another object of the present invention is to provide an optical resin composition having particularly excellent impact resistance, an optical resin sheet using the same, an optical filter for plasma display using the same, and a plasma display. To do.

The present invention relates to the following.
1. 15 to 60 parts by weight of copolymer 39 to 84 parts by weight of monomer having one acryloyl group 0.5 to 10 parts by weight of monomer having two or more acryloyl groups and 0.3 to 3 parts by weight of a photopolymerization initiator,
The above copolymer is an alkyl acrylate having 4 to 18 carbon atoms in an alkyl group (hereinafter referred to as AA monomer) of 50 to 87% by weight and the following general formula (I)

（ただし、式中、ｍは２、３又は４、ｎは１〜１０の整数をしめす。）
で表されるヒドロキシル基含有アクリレート（以下、ＨＡモノマーという。）１３〜５０重量％を重合させて得られるものであり、
上記のアクリロイル基を１個有するモノマーとして、ＡＡモノマーを５０〜８７重量％及びＨＡモノマーを１３〜５０重量％の割合になるように使用し、
上記コポリマー中のＨＡモノマーの割合（Ｐ重量％）と、アクリロイル基を１個有するモノマーにおけるＨＡモノマーの割合（Ｍ重量％）との間に、

(In the formula, m represents 2, 3 or 4, and n represents an integer of 1 to 10.)
It is obtained by polymerizing 13 to 50% by weight of a hydroxyl group-containing acrylate represented by the following (hereinafter referred to as HA monomer),
As a monomer having one acryloyl group as described above, an AA monomer is used in a proportion of 50 to 87% by weight and an HA monomer in a proportion of 13 to 50% by weight,
Between the proportion of HA monomer in the copolymer (P wt%) and the proportion of HA monomer in the monomer having one acryloyl group (M wt%),

の関係があるように配合されてなる光学用樹脂組成物。
２． 重合開始剤がα−ヒドロキシアルキルフェノン系化合物あるいはアシルフォスフィンオキサイド系化合物あるいはオリゴ（２−ヒドロキシ−２−メチル−１−（４−（１−メチルビニル）フェニル）プロパノン）である項１記載の光学用樹脂組成物。
３． ＡＡモノマーが２−エチルヘキシルアクリレートまたはイソオクチルアクリレートまたはｎ−オクチルアクリレートであり、ＨＡモノマーが２−ヒドロキシエチルアクリレートまたは１−ヒドロキシエチルアクリレートまたは２−ヒドロキシプロピルアクリレートまたは３−ヒドロキシプロピルアクリレートまたは１−ヒドロキシプロピルアクリレートまたは４−ヒドロキシブチルアクリレートまたは３−ヒドロキシブチルアクリレートまたは２−ヒドロキシブチルアクリレートまたは１−ヒドロキシブチルアクリレートである項１又は２記載の 樹脂組成物。
４． コポリマーの重量平均分子量が２００，０００〜３５０，０００である項１〜３のいずれかに記載の光学用樹脂組成物。
５． コポリマ ４０〜６０重量部、
アクリロイル基を１個有するモノマー ３９〜５９ 重量部、
アクリロイル基を２個以上有するモノマー １〜５重量部、
及び
光重合開始剤 ０．５〜２．０重量部
を含有する請求項１〜４のいずれかに記載の光学用樹脂組成物。
６． 項１〜５のいずれかに記載の樹脂組成物からなる光学用樹脂シート。
７． 項１〜５のいずれかに記載の樹脂組成物又は請求項６記載の光学用樹脂シートを使用して得られるプラズマディスプレイパネル用衝撃吸収層を備えたプラズマディスプレイ用光学フィルタ。
８． 項１〜５のいずれかに記載の樹脂組成物又は請求項６記載の光学用樹脂シートを使用して得られるプラズマディスプレイ。

An optical resin composition formulated so as to have the following relationship.
2. Item 2. The polymerization initiator according to Item 1, wherein the polymerization initiator is an α-hydroxyalkylphenone compound, an acyl phosphine oxide compound, or oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone). Optical resin composition.
3. AA monomer is 2-ethylhexyl acrylate or isooctyl acrylate or n-octyl acrylate, and HA monomer is 2-hydroxyethyl acrylate or 1-hydroxyethyl acrylate or 2-hydroxypropyl acrylate or 3-hydroxypropyl acrylate or 1-hydroxypropyl Item 3. The resin composition according to Item 1 or 2, which is acrylate, 4-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, 2-hydroxybutyl acrylate, or 1-hydroxybutyl acrylate.
4). Item 4. The optical resin composition according to any one of Items 1 to 3, wherein the copolymer has a weight average molecular weight of 200,000 to 350,000.
5. 40-60 parts by weight of copolymer,
39 to 59 parts by weight of a monomer having one acryloyl group,
1 to 5 parts by weight of a monomer having two or more acryloyl groups,
And the optical polymerization composition in any one of Claims 1-4 containing 0.5-2.0 weight part of photoinitiators.
6). The optical resin sheet which consists of a resin composition in any one of claim | item 1 -5.
7). The optical filter for plasma displays provided with the impact absorption layer for plasma display panels obtained using the resin composition in any one of claim | item 1 -5, or the optical resin sheet of Claim 6.
8). The plasma display obtained using the resin composition in any one of Claims 1-5, or the optical resin sheet of Claim 6.

The optical resin composition according to the present invention has impact absorption, is excellent in moisture resistance reliability, and does not become cloudy even under humid conditions.
In addition, the optical resin composition and the optical resin sheet according to the present invention have high polymer solubility because the compositions of the polymer and the monomer are almost the same, and even if a high molecular weight polymer is used, a transparent resin composition or A cured product can be produced. Furthermore, since it is diluted with a monomer, it can be molded without a solvent, and a thick film without bubbles can be produced.
In addition, since it contains a high molecular weight polymer at a relatively high concentration, it has excellent shock absorption even at a thin film thickness. Moreover, it has hardness and can suppress a decrease in scratch resistance. Due to this hardness, it is difficult to plastically deform, and it is possible to exhibit better shock absorption with a thick film thickness. Furthermore, since it has high cohesive force and is stretchable, it is less likely to crack or streak when the film is bent or wound around a roll.
Moreover, the optical resin composition according to the present invention generally does not attack materials used for displays.
The optical resin composition according to the present invention can produce an optical resin sheet, and this resin sheet also exhibits the same effects as the optical resin composition described above.
The optical filter for plasma display and the plasma display provided with the impact absorbing layer obtained by using the above optical resin composition or optical resin sheet inherit the same functions and effects as those of the optical resin composition described above.

  Examples of the AA monomer in the present invention include n-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, stearyl acrylate, and the like. Acrylate, isooctyl acrylate, 2-ethylhexyl acrylate and n-octyl acrylate are preferred, and 2-ethylhexyl acrylate is particularly preferred. These acrylates may be used in combination of two or more.

  As the HA monomer in the present invention, 2-hydroxyethyl acrylate, 1-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 1-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, Hydroxyl-containing acrylates such as 2-hydroxybutyl acrylate and 1-hydroxybutyl acrylate, polyethylene glycol monoacrylates such as diethylene glycol and triethylene glycol, polypropylene glycol monoacrylates such as dipropylene glycol and tripropylene glycol, dibutylene glycol and tributylene glycol And polybutylene glycol monoacrylate such as 2- Droxyethyl acrylate, 1-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 1-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, 2-hydroxybutyl acrylate, 1-hydroxy Butyl acrylate is preferred, and 2-hydroxyethyl acrylate is particularly preferred. These acrylates may be used in combination of two or more.

The copolymer obtained by polymerizing AA monomer and HA monomer in the present invention has a weight average molecular weight (measured using a standard polystyrene calibration curve by gel permeation chromatography, the same shall apply hereinafter) of 100,000 to 600,000. Are preferred, 150,000 to 400,000 are more preferred, and 200,000 to 350,000 are more preferred.
As a method for synthesizing the copolymer, known polymerization methods such as solution polymerization, suspension polymerization, emulsion polymerization and bulk polymerization can be used, but solution polymerization or bulk polymerization is preferable. As the polymerization initiator, a compound capable of generating radicals by heat can be used. Specifically, benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n- Propyl peroxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate, t-butylperoxyneodecanoate, t-butylperoxybivalate, (3,5,5-trimethylhexanoyl) peroxide, di Organic peroxides such as propionyl peroxide, diacetyl peroxide, didodecyl peroxide, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1, 1'-azobis (cyclohexane-1-carbonyl). 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate) ), 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-hydroxymethylpropionitrile), 2,2′-azobis [2- (2-imidazolin-2-yl) ) Propane].

  In the present invention, monomers having two or more acryloyl groups include bisphenol A diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1, 3-butylene glycol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, glycerol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, polybutylene glycol diacrylate, trimethylolpropane triacrylate, penta Erythritol triacrylate, tris (acryloxyethyl) isocyanurate, pentaerythritol tetraacryl Acrylate monomers such as acrylate monomers, dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and acrylic oligomers such as epoxy acrylate, polyester acrylate, urethane acrylate, and acrylic acrylate. Diacrylates such as diol diacrylate, 1,9-nonanediol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, and polypropylene glycol diacrylate are preferred.

  In the present invention, those having sensitivity to light such as ultraviolet rays are used as the photopolymerization initiator. For example, benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler's ketone), 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1- Phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methyl Vinyl) phenyl) propanone) and the like, but those that do not color the resin composition are 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4 -(2-Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propyl Α-hydroxyalkylphenone compounds such as pan-1-one, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl- Acylphosphine oxide compounds such as pentylphosphine oxide and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) Propanone) and combinations thereof are preferred. In order to produce a particularly thick sheet, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, A photopolymerization initiator containing an acylphosphine oxide compound such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide is preferred. In order to reduce the odor of the sheet, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) is preferable. These photopolymerization initiators may be used in combination.

The optical resin composition of the present invention comprises:
Copolymer 15-60 parts by weight, preferably 30-60 parts by weight, more preferably 40-60 parts by weight Monomer having one acryloyl group 39-84 parts by weight, preferably 39-69 parts by weight, more preferably 39 to 59 parts by weight,
Monomer having 2 or more acryloyl groups 0.5 to 10 parts by weight, preferably 1 to 10 parts by weight,
And a photoinitiator 0.3-3 weight part, Preferably, it contains 0.5-2 weight part.
If the amount of the copolymer is too small, there will be a problem in mechanical properties, and the impact absorbability will be lowered when used in a shock absorbing layer for PDP. Further, curing shrinkage becomes large, and a problem is likely to occur in the flatness of the film. On the other hand, if the amount is too large, the viscosity of the composition becomes too high, making it difficult to produce a sheet.
When the amount of the monomer having one acryloyl group is too small, the viscosity of the composition becomes too high, making it difficult to produce a sheet. When the amount is too large, there is a problem in mechanical properties.
If the amount of the monomer having two or more acryloyl groups is too small, it is difficult to maintain the shape of the cured product of the resin composition. Conversely, if the amount of the monomer is too large, the cured product of the resin composition becomes brittle and causes problems in mechanical properties. .
When the amount of the photopolymerization initiator is too small, the reaction does not proceed sufficiently. On the other hand, when the amount is too large, a large amount of the photopolymerization initiator remains, resulting in problems in optical properties and mechanical properties. In addition, when hardening said resin composition for optics by irradiation of an electron beam, it is not necessary to use a photoinitiator.

The copolymer is obtained by polymerizing 50 to 87% by weight of AA monomer, preferably 60 to 70% by weight, and 13 to 50% by weight, preferably 30 to 40% by weight of HA monomer.
As the monomer having one acryloyl group, AA monomer is 50 to 87% by weight, preferably 60 to 70% by weight, and HA monomer is 13 to 50% by weight, preferably 30 to 40% by weight. is there.
In these, if there are too many AA monomers, therefore, if there are too few HA monomers, the hardened | cured material of the resin composition concerning this invention will become easy to become cloudy at the time of moisture absorption, conversely, if there are too many HA monomers, therefore, AA monomer When there is too little, the hardened | cured material of the resin composition which concerns on this invention will deform | transform easily at the time of moisture absorption.

  In the present invention, between the ratio of HA monomer in the copolymer (P wt%) and the ratio of HA monomer in the monomer having one acryloyl group (M wt%),

の関係があるようにそれぞれの配合が調整される。（Ｐ−Ｍ）が上記の式を満足しない場合、硬化時に本発明に係る樹脂組成物が白濁しやすくなる。前記コポリマー及びアクリロイル基を１個有するモノマーにおいて、ＡＡモノマー（及びＨＡモノマー）が、前記した好ましい割合にあるときは、常にこの条件を満足する。

Each formulation is adjusted so that When (P-M) does not satisfy the above formula, the resin composition according to the present invention tends to become cloudy during curing. In the copolymer and the monomer having one acryloyl group, this condition is always satisfied when the AA monomer (and the HA monomer) are in the preferred ratio as described above.

The optical resin composition in the present invention is preferably formed or laminated on the display surface so that the film thickness is 0.1 mm to 3 mm. In consideration of impact absorption, a thickness of 0.2 mm or more is more preferable. In particular, when it is desired to increase shock absorption, the thickness is preferably 1.3 mm or more. After coating on the display surface or the substrate of the optical filter to form a film, the film is cured by irradiation with light such as ultraviolet rays or radiation such as an electron beam. When producing an optical filter, after forming the optical resin composition in the present invention on the base material or functional layer of the optical filter, further laminating the base material, functional layer or protective layer of the optical filter. It may be cured by irradiation with radiation.
The optical resin sheet in the present invention preferably has a film thickness of 0.1 mm to 3 mm. In consideration of impact absorption, a thickness of 0.2 mm or more is more preferable. In particular, when it is desired to increase shock absorption, the thickness is preferably 1.3 mm or more. This can be produced by casting a mixture of the monomer raw material and the polymerization initiator. Moreover, it can manufacture by apply | coating desired thickness using a general purpose coating machine, and irradiating radiation, such as light rays, such as an ultraviolet-ray, and an electron beam.
In the case where oxygen is present in the optical resin composition in the present invention due to ultraviolet rays or the like, it is preferable to cover the resin surface with a transparent film or transparent glass for blocking oxygen. As the ultraviolet irradiation device, a high-pressure mercury lamp, a metal halide lamp, or the like can be used.
Even if the optical resin composition of the present invention is thickly formed and the optical resin sheet of the present invention is thick, it contains a high molecular weight copolymer, so that the cured resin has hardness. It is hard to be plastically deformed with respect to an impact. Therefore, it is easy to improve the shock absorption by increasing the thickness.

The optical resin composition or the optical resin sheet in the present invention is formed or laminated on a functional layer such as an antireflection layer, an electromagnetic wave shielding layer, a near infrared shielding layer, or a base film such as a polyethylene film. It can be used as a multilayer product or as an optical filter comprising such a multilayer product.
As the electromagnetic wave shielding layer, a known electromagnetic wave shielding layer can be used as long as it has an electromagnetic wave shielding property with a visible light transmittance of 60% or more. A transparent conductive film, a conductive fiber mesh, a mesh made of a conductive ink, or the like can be used, but a metal mesh is most preferable from the viewpoint of high transparency and high electromagnetic shielding properties. The metal mesh is produced by applying an adhesive to one or both of a transparent base material such as a polyester film and a conductive metal foil such as copper foil and aluminum foil, and then bonding the two together, and then the metal foil is subjected to a chemical etching process. Obtained by etching. At this time, it is preferable to use a conductive metal foil having a rough surface in order to ensure adhesion. The conductive metal foil is laminated so that the rough surface faces the adhesive layer. If a metal mesh is produced by the etching described above, a resin is applied thereon, particularly preferably a resin curable by irradiation with radiation such as ultraviolet rays or electron beams, and radiation such as ultraviolet rays or electron beams. The adhesive layer to which the rough surface has been transferred is preferably made transparent by irradiating and curing. The resin composition of the present invention can be used as a resin used for transparency or as a resin that serves as both a transparency and an impact absorbing layer.
Further, the antireflection layer may be a layer having antireflection properties such that the visible light reflectance is 5% or less, and is processed by a known antireflection method on a transparent substrate such as a transparent plastic film. Layers can be used.
Furthermore, the near-infrared shielding layer is made of a resin layer in which a near-infrared absorbing material such as an imonium salt or a near-infrared shielding material is dispersed, and can be laminated on a transparent substrate such as a transparent plastic film. Near-infrared shielding ability can be imparted by dispersing a near-infrared absorbing material such as an immonium salt or a near-infrared shielding material in the optical resin composition or the optical resin sheet of the present invention.

The optical resin composition in the present invention or the above-mentioned optical resin sheet, electromagnetic wave shielding layer, antireflection layer, near infrared shielding layer, and other functional layers can be used by appropriately stacking necessary ones. In this case, the functional layer may be laminated on one side of the transparent substrate, or layers having different functions may be separately provided on both sides of the transparent substrate, and layers having the same function may be laminated on both sides. good. The order of stacking the functional layers is arbitrary.
In the case of such a multilayer product, it is preferable that the optical resin composition or the optical resin sheet in the present invention is the outermost layer.
These layers can be laminated | stacked with a roll lamination or a single wafer bonding machine through the adhesion layer between each layer. Furthermore, the multilayer material laminated | stacked with the roll lamination and the sheet | seat bonding machine can be bonded to the display front surface or the display front board using a roll laminator or a sheet bonding machine. In this case, the layer made of the protective member of the present invention is preferably bonded so as to face the front surface of the display or the display front plate (in many cases, functions as an optical filter). Examples of the display include a PDP, a liquid crystal display (LCD) panel, and a cathode ray tube (CRT).

Into a reaction vessel equipped with a condenser, thermometer, stirrer, dropping funnel and nitrogen injection tube, 84.0 g of 2-ethylhexyl acrylate, 36.0 g of 2-hydroxyethyl acrylate and 150.0 g of methyl isobutyl ketone are taken as initial monomers. While substituting with nitrogen at an air volume of 100 ml / min, the mixture was heated from room temperature to 70 ° C. for 15 minutes. Thereafter, while maintaining this temperature, 21.0 g of 2-ethylhexyl acrylate and 9.0 g of 2-hydroxyethyl acrylate were used as additional monomers, and a solution in which 0.6 g of lauryl peroxide was dissolved was prepared. The solution was added dropwise over 60 minutes and allowed to react for an additional 2 hours after completion of the addition. Subsequently, methyl isobutyl ketone was distilled off to obtain a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 250,000).
Next, 44.50 g of this copolymer,
38.25 g of 2-ethylhexyl acrylate,
16.25 g of 2-hydroxyethyl acrylate,
1.00 g of 1,6-hexanediol diacrylate,
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
After stirring and mixing, the mixture was poured into a frame having a width of 100 mm, a depth of 100 mm, and a depth of 0.5 mm, and the upper part was covered with an ultraviolet transmissive glass and irradiated with 2,000 mJ of ultraviolet rays using a UV irradiation device to be transparent. A good sheet was obtained. This sheet was transparent even after the moisture absorption test. Next, this sheet was bonded onto an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. The glass was broken by an impact of 1.2 J. Moreover, the damage of the resin sheet was not seen.

19.75 g of the copolymer obtained in Example 1
2-ethylhexyl acrylate 55.50 g,
2-hydroxyethyl acrylate 23.75 g,
1.00 g of 1,6-hexanediol diacrylate,
as well as
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. This sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was bonded onto an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. The glass was broken by an impact of 1.2 J. Moreover, the damage of the resin sheet was not seen.

54.50 g of the copolymer obtained in Example 1;
31.25 g of 2-ethylhexyl acrylate,
13.25 g of 2-hydroxyethyl acrylate,
1.00 g of 1,6-hexanediol diacrylate,
as well as
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. This sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was bonded onto an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. The glass was broken by an impact of 1.2 J. Moreover, the damage of the resin sheet was not seen.

Example 1 except that 102.0 g of 2-ethylhexyl acrylate and 18.0 g of 2-hydroxyethyl acrylate were used as initial monomers and 25.5 g of 2-ethylhexyl acrylate and 4.5 g of 2-hydroxyethyl acrylate were used as additional monomers. In the same manner, a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 200,000) was obtained.
Next, 44.50 g of this copolymer,
46.25 g of 2-ethylhexyl acrylate,
8.25 g of 2-hydroxyethyl acrylate,
1.00 g of 1,6-hexanediol diacrylate,
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. This sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was laminated on an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. The glass was broken by an impact of 1.4 J. Moreover, the damage of the resin sheet was not seen.

Example 1 except that 60.0 g of 2-ethylhexyl acrylate and 60.0 g of 2-hydroxyethyl acrylate were used as initial monomers and 15.0 g of 2-ethylhexyl acrylate and 15.0 g of 2-hydroxyethyl acrylate were used as additional monomers. In the same manner as described above, a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 350,000) was obtained.
Next, 44.50 g of this copolymer,
27.25 g of 2-ethylhexyl acrylate,
2-hydroxyethyl acrylate 27.25 g,
1.00 g of 1,6-hexanediol diacrylate,
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1 except for adding. This sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was bonded onto an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. The glass was broken by an impact of 1.2 J.
Moreover, the damage of the resin sheet was not seen.

  As a photopolymerization initiator, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide is used instead of 1-hydroxy-cyclohexyl-phenyl-ketone, and has a width of 100 mm, a depth of 100 mm, and a depth of 3.0 mm. A sheet was prepared in the same manner as in Example 1 except that a frame was used and the exposure amount of ultraviolet rays was changed to 4,500 mJ. This sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was laminated on an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. Did not break. Moreover, the damage of the resin sheet was not seen.

  As a photopolymerization initiator, 2.00 g of oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) was used instead of 1-hydroxy-cyclohexyl-phenyl-ketone, A sheet was prepared in the same manner as in Example 1 except that the amount of ultraviolet light exposure was 2,500 mJ. This sheet was transparent and maintained transparency after the moisture absorption test. This sheet had a particularly low odor. Next, this sheet was bonded onto an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. The glass was broken by an impact of 1.2 J. Moreover, the damage of the resin sheet was not seen.

  A sheet was produced in the same manner as in Example 1 except that a frame having a width of 100 mm, a depth of 100 mm, and a depth of 1.5 mm was used, and the exposure amount of ultraviolet rays was set to 3,500 mJ. This sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was laminated on an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. Did not break. Moreover, the damage of the resin sheet was not seen.

  A sheet was produced in the same manner as in Example 1 except that a frame having a width of 100 mm, a depth of 100 mm, and a depth of 2.0 mm was used, and the exposure amount of ultraviolet rays was set to 4,000 mJ. This sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was laminated on an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. Did not break. Moreover, the damage of the resin sheet was not seen.

40.20 g of the copolymer obtained in Example 1
44.10 g of 2-ethylhexyl acrylate,
14.70 g of 2-hydroxyethyl acrylate,
1.00 g of 1,6-hexanediol diacrylate,
as well as
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. This sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was bonded onto an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. The glass was broken by an impact of 1.2 J. Moreover, the damage of the resin sheet was not seen.

Comparative Example 1
44.50 g of the copolymer obtained in Example 1
54.50 g of 2-ethylhexyl acrylate,
13.25 g of 2-hydroxyethyl acrylate,
1.00 g of 1,6-hexanediol diacrylate,
as well as
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. The obtained sheet was cloudy.

Comparative Example 2
44.50 g of the copolymer obtained in Example 1
54.50 g of 2-ethylhexyl acrylate,
1.00 g of 1,6-hexanediol diacrylate,
as well as
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. The obtained sheet was cloudy.

Comparative Example 3
Example 1 except that 108.0 g of 2-ethylhexyl acrylate and 12.0 g of 2-hydroxyethyl acrylate were used as initial monomers, and 27.0 g of 2-ethylhexyl acrylate and 3.0 g of 2-hydroxyethyl acrylate were used as additional monomers. Similarly, a copolymer (weight average molecular weight 220,000) was obtained.
49.50 g of the copolymer obtained above,
44.50 g of 2-ethylhexyl acrylate,
5.00 g of 2-hydroxyethyl acrylate,
1.00 g of 1,6-hexanediol diacrylate,
as well as
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. The obtained sheet was transparent, but became cloudy after the moisture absorption test.

Comparative Example 4
Example 1 except that 12.0 g of 2-ethylhexyl acrylate and 108.0 g of 2-hydroxyethyl acrylate were used as initial monomers, and 3.0 g of 2-ethylhexyl acrylate and 27.0 g of 2-hydroxyethyl acrylate were used as additional monomers. A copolymer was obtained in the same manner.
49.50 g of the copolymer obtained above,
5.00 g of 2-ethylhexyl acrylate,
44.50 g of 2-hydroxyethyl acrylate,
1.00 g of 1,6-hexanediol diacrylate,
as well as
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. The obtained sheet was transparent, but after the moisture absorption test, the outer dimensions were enlarged by 5% or more, and undulation was generated in the outer peripheral portion.

Comparative Example 5
A sheet was prepared in the same manner as in Example 1 except that 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 was used as a photopolymerization initiator. The produced sheet was colored yellow.

Comparative Example 6
84.15 g of 2-ethylhexyl acrylate,
14.85 g of 2-hydroxyethyl acrylate,
1.00 g of 1,6-hexanediol diacrylate,
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. This sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was laminated on an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. The sheet was damaged.

Comparative Example 7
When the electromagnetic wave shielding film U (TT42-01) A was directly bonded to the glass so that the electromagnetic wave shielding layer was in contact therewith and subjected to an impact resistance test, the glass was broken by an impact of 0.5 J.
Comparative Example 8
10.00 g of the copolymer obtained in Example 1
62.30 g of 2-ethylhexyl acrylate,
2-hydroxyethyl acrylate 26.70 g,
1.00 g of 1,6-hexanediol diacrylate,
as well as
1-hydroxy-cyclohexyl-phenyl-ketone 0.50 g
A sheet was prepared in the same manner as in Example 1. The obtained sheet was transparent and maintained transparency after the moisture absorption test. Next, this sheet was bonded onto an electromagnetic wave shielding layer of an electromagnetic wave shielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected to an impact resistance test. The glass was broken with an impact of 0.8 J.

Test methods in Examples and Comparative Examples are shown below. The test results are shown in Table 1 or Table 2.
(Hygroscopic test)
The moisture absorption test was performed by placing the resin sheet in a high temperature and high humidity test tank of 60 ° C. and 90% RH for 50 hours, and the evaluation method was visually observed. Moreover, the total light transmittance after a test was measured.
(Molecular weight measurement)
The molecular weight was measured using gel permeation chromatography using THF as a solvent, and the molecular weight was determined using polystyrene as a standard substance.
(Impact resistance test)
The impact resistance test was evaluated by further bonding the resin sheet to the electromagnetic wave shielding film to a soda glass having a thickness of 2.8 mm and dropping a steel ball. The impact was increased in units of 0.1 J, and the value just before the glass or resin sheet was damaged was defined as impact resistance.
(Total light transmittance)
The total light transmittance was measured using a color difference / turbidity measuring device COH-300A (manufactured by Nippon Denshoku Industries Co., Ltd.).

Claims (8)

15 to 60 parts by weight of copolymer 39 to 84 parts by weight of monomer having one acryloyl group 0.5 to 10 parts by weight of monomer having two or more acryloyl groups and 0.3 to 3 parts by weight of a photopolymerization initiator,
The above copolymer is an alkyl acrylate having 4 to 18 carbon atoms in an alkyl group (hereinafter referred to as AA monomer) of 50 to 87% by weight and the following general formula (I)

(In the formula, m represents 2, 3 or 4, and n represents an integer of 1 to 10.)
It is obtained by polymerizing 13 to 50% by weight of a hydroxyl group-containing acrylate represented by the following (hereinafter referred to as HA monomer),
As a monomer having one acryloyl group as described above, an AA monomer is used in a proportion of 50 to 87% by weight and an HA monomer in a proportion of 13 to 50% by weight,
Between the proportion of HA monomer in the copolymer (P wt%) and the proportion of HA monomer in the monomer having one acryloyl group (M wt%),

An optical resin composition formulated so as to have the following relationship.   The polymerization initiator is an α-hydroxyalkylphenone compound, an acyl phosphine oxide compound, or an oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone). An optical resin composition.   AA monomer is 2-ethylhexyl acrylate or isooctyl acrylate or n-octyl acrylate, and HA monomer is 2-hydroxyethyl acrylate or 1-hydroxyethyl acrylate or 2-hydroxypropyl acrylate or 3-hydroxypropyl acrylate or 1-hydroxypropyl The optical resin composition according to claim 1 or 2, which is acrylate, 4-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, 2-hydroxybutyl acrylate, or 1-hydroxybutyl acrylate.   The optical resin composition according to any one of claims 1 to 3, wherein the copolymer has a weight average molecular weight of 200,000 to 350,000. 40-60 parts by weight of copolymer,
39 to 59 parts by weight of a monomer having one acryloyl group,
1 to 5 parts by weight of a monomer having two or more acryloyl groups,
And the optical resin composition in any one of Claims 1-4 which contains 0.5-2.0 weight part of photoinitiators.   The optical resin sheet which consists of a resin composition in any one of Claims 1-5.   The optical filter for plasma displays provided with the impact absorption layer for plasma display panels obtained using the resin composition in any one of Claims 1-5, or the optical resin sheet of Claim 6. A plasma display panel obtained by using the resin composition according to any one of Items 1 to 5 or the optical resin sheet according to claim 6.