JP2012126839A - Ultraviolet curing resin composition for optics, cured material, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a liquid ultraviolet curing resin composition which cures by ultraviolet irradiation, has the performance to stably hold heat resistance, light resistance and moisture resistance, that is, optical qualities over a long period, and is excellent in repealability, impact resistance and workability; a cured material thereof; and a display device having the cured material obtained by curing the ultraviolet curing resin composition.SOLUTION: The ultraviolet curing resin composition for optics includes: (A) a compound obtained by the reaction of a polyether monool (a-1) with a (meth)acrylate (a-2) having an isocyanate group; and (B) a photopolymerization initiator.

Description

  The present invention provides a space between a display panel of an image display device used in a mobile phone, a liquid crystal television, a plasma television, an electronic book, a touch panel, and the like and a protective plate installed on the display panel with a predetermined interval. It is related with the ultraviolet curable resin composition for optics with which it fills.

  In flat panel displays such as liquid crystal display panels, when a shock is applied, a transparent protection consisting of a display panel and an acrylic plate or glass plate that protects the display panel so that the shock is not transmitted to the display panel A certain gap is provided between the plates.

  When this gap is an air layer, the loss of light due to the difference in refractive index between the material constituting the display panel and the protective plate and the air layer is large, and good visibility cannot be obtained. In recent years, a transparent substance is interposed in the gap. Transparent polymer materials such as transparent resin sheets, adhesive transparent gels, and curable adhesive resin compositions have been proposed as transparent substances.

  As the transparent resin sheet, for example, a pressure-sensitive adhesive sheet having a gel fraction of 50 to 90% by weight and a storage elastic modulus of a predetermined value or less with a (meth) acrylic pressure-sensitive adhesive (JP 2009-263502 A (Patent Document 1) )), An acrylic acid alkyl ester, a copolymer of a polar monomer having a Tg of 50 ° C. or higher, and a hydrophilic monomer having an oxyalkylene group, and having a tan δ and a storage elastic modulus of a predetermined value or less 2010-163591 (Patent Document 2)) and the like have been proposed. In the pressure-sensitive adhesive sheet of Patent Document 2, the presence of a photopolymerization initiator for the above various monomers (acrylic acid alkyl ester, polar monomer having a homopolymer Tg of 50 ° C. or higher, and (meth) acrylic ester having an oxyalkylene group) By adding a cross-linking agent (1,6-hexanediol diacrylate) and an additional polymerization initiator to a viscous liquid obtained by partial polymerization by irradiating with ultraviolet light, and further curing by irradiation with light. (Example of paragraph number 0067).

  The transparent resin sheet has an advantage that it is easier for the user who assembles the display device than the gel or the like. Furthermore, in the case of a transparent sheet using a (meth) acrylic monomer as the main structural unit of the polymer, there is an advantage that it is excellent in adhesiveness as compared with silicone gel and other resins.

  On the other hand, as the screen size increases, the transparent sheets used for these must also be enlarged, but it is not easy to handle large sheets having viscoelasticity for ensuring predetermined adhesiveness and shock absorption. Since it is necessary to attach the interface between the display panel and the protective plate so as not to generate bubbles and wrinkles, a high-level transparent resin sheet requires a high level of technology for the affixing operation. In particular, due to the demand for thin display devices, there is a strict demand for thinning the transparent resin sheet used therefor, and skilled techniques are required for its handling. Furthermore, when bubbles and wrinkles are generated, a performance (removability or repairability) that can easily re-stretch the transparent sheet is also strongly required.

  In addition, anti-glare treatment is applied to the display panel and the protective plate, and a black printed layer is applied to the outer peripheral edge of the back surface of the protective plate (the surface on the side in contact with the sheet) to make the liquid crystal screen easier to see. There is. In these cases, since unevenness is formed on the adhesive surfaces of the display panel and the protective plate that are adherends, it is necessary to use a soft adhesive sheet that can absorb the level difference caused by the printing unit. This demands higher handling technology from users.

  In this respect, since the curable resin composition is provided in a liquid state, it can be applied to various sizes of display screens and is excellent in versatility. In addition, since the work of curing after filling the space between the display panel and the protective plate does not depend on the size of the display screen, there is no problem of sophistication of work technology due to the enlargement of the screen. In addition, since the distance between the display panel and the protective plate varies depending on the type of user and product, in the case of a resin sheet, resin sheets with various thicknesses corresponding to the gap size are required. In the case of a thing, it can respond with one type of resin composition irrespective of the space | interval size with which it fills. Furthermore, there is an advantage that even a display device having an uneven surface can be filled without a gap.

  On the other hand, in the case of a curable resin composition, shrinkage due to curing or filling work may be a problem.

  Examples of the curable resin composition used in the display device include, for example, JP 2009-186963 A (Patent Document 3), polymers such as polyisoprene acrylate, terpene hydrogenated resin, butadiene, and ultraviolet curable monomers. An ultraviolet curable resin composition containing the above has been proposed.

  In Patent Document 3, a cured product with less distortion is obtained by using a resin composition having a high elongation rate of the cured product. However, from the viewpoint of improving the clarity of display, further reduction of the shrinkage rate is required. It is done. Furthermore, rubber polymers such as polyisoprene-based and butadiene-based polymers contain many double bonds in the molecular chain, and these do not participate in the ultraviolet curing reaction, so that double bonds remain in the cured product. There is a risk. Residual double bonds cause a decrease in light resistance and heat resistance. Degradation and yellowing of rubber-based polymers under severe conditions under high temperature and high humidity not only deteriorate optical properties but also decrease elongation and viscoelastic properties. As a result, display panels and protective plates Bubbles and peeling may occur at the interface with each other, which may cause a reduction in display performance of the display device.

  In addition, when a highly viscous material such as polyisoprene acrylate is used, the resulting resin composition has a high viscosity, which requires excessive time for filling, resulting in poor productivity and high manufacturing cost. There is a risk.

JP 2009-263502 A JP 2010-163591 A JP 2009-186963 A

  The present invention has been made in view of the above circumstances, and the object of the present invention is a liquid that can be applied to display devices of various sizes and display devices having irregularities on the adherend surface. This resin composition has excellent heat resistance, light resistance, moisture resistance, that is, the ability to stably maintain optically superior quality over a long period of time, and excellent removability, impact resistance, and workability. Another object of the present invention is to provide a display device having an ultraviolet curable resin composition, a cured product thereof, and a cured product obtained by curing such a resin composition.

  That is, the optical ultraviolet curable resin composition of the present invention is an ultraviolet curable resin composition used for laminating and integrating a display panel and a protective plate of a display device, and the ultraviolet curable resin composition Comprising (A) a compound obtained by the reaction of a polyether monool (a-1) and a (meth) acrylate (a-2) having an isocyanate group, and (B) a photopolymerization initiator. And

  The polyether monool (a-1) preferably has a number average molecular weight of 1000 or more. Moreover, it is preferable that the said polyether monool (a-1) contains polyoxypropylene monool.

The optical ultraviolet resin curable resin composition of the present invention further includes (C) a plasticizer.

The UV curable resin composition for optics of the present invention preferably has a viscosity at 25 ° C. of 200 to 10,000 mPa · s.

  The present invention also includes a cured product obtained by curing the above-described optical ultraviolet curable resin composition of the present invention by ultraviolet irradiation, and also a display device having the cured product.

  The optical ultraviolet curable resin composition of the present invention is a viscous liquid that is cured by irradiation with ultraviolet rays, and has heat resistance, light resistance, moisture resistance, that is, the ability to stably maintain optically excellent quality over a long period of time. Further, it is possible to provide a cured product excellent in removability, impact resistance absorption and workability. Therefore, it is suitable as a transparent polymer material filled in the display device.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a display device using the cured product of the present invention. FIG. 2 is a schematic cross-sectional view showing another embodiment of a display device using the cured product of the present invention.

The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and is not limited to these contents.
<Optical UV curable resin composition>
First, the optical ultraviolet curable resin composition of the present invention will be described.

The optical ultraviolet curable resin composition of the present invention (hereinafter sometimes referred to as a resin composition) is used for laminating and integrating a display panel and a protective plate of a display device. ) Compound obtained by reaction of polyether monool (a-1) with (meth) acrylate (a-2) having an isocyanate group (hereinafter sometimes referred to as compound (A)), and (B ) It contains a photopolymerization initiator.
[Polyether monool (a-1)]
The polyether monool (a-1) reacts with the (meth) acrylate (a-2) having an isocyanate group described later to form a compound (A) having (meth) acrylate in the molecule. It is.
The polyether polymonool (a-1) is not particularly limited as long as it has a repeating unit represented by the following general formula (1) in the compound and has one hydroxyl group.

Formula (1): —R—O—
R preferably has a linear and / or branched alkylene group having 1 to 14 carbon atoms, specifically, —CH ₂ O—, —CH ₂ CH ₂ O—, —CH ₂ CH (CH _{3) O -, - CH 2} CH (C 2 H 5) O-, CH 2 C (CH 3) 2 O -, - CH 2 CH 2 CH 2 CH 2 O -, - COCH 2 CH 2 CH 2 CH 2 CH ₂ O—, —CH ₂ C (CH ₃ ) ₂ CH ₂ O— and the like are mentioned, among which —CH ₂ CH ₂ O—, —CH ₂ CH (CH ₃ ) O— are preferred, CH ₂ CH (CH ₃ ) O— is particularly preferred.
The repeating unit contained in these polyether monools (a-1) may consist of only one type of repeating unit, or may consist of two or more types of repeating units. These polyether monools (a-1) may contain repeating units other than the above structure. 80 mass% or more is preferable, as for the content rate of general formula (1) in polyether monool (a-1), More preferably, it is 90 mass% or more, Most preferably, it is 95 mass% or more. When the content ratio of the general formula (1) is 80% by mass or more, a compound having a (meth) acrylate in the molecule (A) obtained by reacting with the (meth) acrylate (a-2) having an isocyanate group (A ) Is reduced, and as a result, a resin composition having excellent workability can be obtained.
As a commercially available polyether monool (a-1), for example, trade name “ADEKA CARPOL” manufactured by ADEKA Corporation is mentioned, and M series mainly composed of propylene oxide, mainly composed of propylene oxide and ethylene oxide. There is an MH series. Furthermore, the product name “New Paul” manufactured by Sanyo Kasei Co., Ltd. is used, and there are LB series mainly composed of propylene oxide, 50HB series mainly composed of propylene oxide and ethylene oxide, and the like.
The molecular weight of the polyether monool (a-1) is preferably a number average molecular weight Mn of 1000 to 20000, more preferably 1000 to 15000, particularly preferably 2000 to 15000, and most preferably 3000 to 15000. If the number average molecular weight Mn is less than 1000, the cured product of the resulting resin composition is hard (high hardness), or the elongation rate is small, and a tendency to be inferior in impact resistance is seen. When the molecular weight Mn exceeds 20000, the viscosity of the resulting resin composition becomes too high, and the workability tends to be inferior.
The molecular weight distribution (Mw / Mn) of the polyether monool (a-1) is preferably 1.5 or less, more preferably 1.4 or less, particularly preferably 1.2 or less, and most preferably 1.1 or less. When the molecular weight distribution (Mw / Mn) is large, the resulting resin composition tends to have high viscosity and poor workability.
The number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) in this specification are all tetrahydrofuran (THF) as a mobile phase, temperature 40 ° C., flow rate 0 Using a Tosoh column TSK-gel SuperHM-H and a TSK-gel SuperH2000, under a condition of 3 mL / min, a gel permeation chromatography (GPC) apparatus manufactured by Tosoh HLC-8220GPC It is a value in terms of standard polystyrene.
[(Meth) acrylate (a-2) having an isocyanate group]
(Meth) acrylate (a-2) having an isocyanate group reacts with the above-described polyether monool (a-1) to form a compound (A) having (meth) acrylate in the molecule. It is.
The (meth) acrylate (a-2) having an isocyanate group is not particularly limited as long as it has an isocyanate group and a (meth) acrylate group, but 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 1,1-bis (acryloyloxymethyl) ethyl isocyanate and the like are preferable, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate are more preferable, 2-acryloyloxyethyl isocyanate Nartes are particularly preferred.

[(A) Compound obtained by reaction of polyether monool (a-1) and (meth) acrylate (a-2) having an isocyanate group]
Although it does not specifically limit as a manufacturing method of a compound (A), For example, heating polyether monool (a-1) and (meth) acrylate (a-2) which has an isocyanate group in presence of a catalyst. And can be obtained by advancing the urethanization reaction. In addition, the compound (A) may contain components other than the polyether monool (a-1) and the (meth) acrylate (a-2) having an isocyanate group as necessary.
Examples of the catalyst that can be used include amines such as triethylamine and benzylmethylamine, dilaurate compounds such as dibutyltin dilaurate and dioctyltin dilaurate, copper naphthenate, cobalt naphthenate, and zinc naphthenate. The amount of the catalyst added is preferably about 0.001 to 1% by mass, particularly preferably about 0.01 to 0.5% by mass, based on the entire reaction mixture.
The reaction temperature is usually 10 to 100 ° C, particularly preferably 30 to 80 ° C. In order to prevent gelation due to radical polymerization during the reaction, it is preferable to add a known polymerization inhibitor. As the polymerization inhibitor, for example, hydroquinone, methoquinone, p-methoxyphenol, p-benzoquinone and the like can be preferably used, and preferably 0.001 to 3% by mass with respect to the entire reaction mixture, 0.01 to 1 More preferably, it is mass%.
The ratio of use of the polyether monool (a-1) and the (meth) acrylate (a-2) having an isocyanate group in the compound (A) is 1 equivalent of a hydroxyl group contained in the polyether monool (a-1). In contrast, it is preferable that the isocyanate group contained in the (meth) acrylate (a-2) having an isocyanate group be 0.40 to 1.05 equivalents, 0.60 to 1.05. The equivalent is more preferable. When the amount is less than 0.40 equivalent, the elongation rate of the cured product of the resulting resin composition is reduced and the impact resistance is inferior. When the amount exceeds 1.05 equivalent, the remaining (meth) acrylate (a- The tendency of heat resistance and light resistance to decrease due to 2) is not preferable.
The proportion of the polyether monool (a-1) in the compound (A) is preferably 90% by mass or more, more preferably 93% by mass or more, particularly preferably 95% by mass or more, and most preferably 97% by mass or more. . When the amount is less than 90% by mass, the heat resistance, light resistance, and moisture resistance tend to be inferior, and the resulting resin composition has a high viscosity and poor workability.
The viscosity at 25 ° C. of the compound (A) is preferably 50 to 10,000 mPa · s, more preferably 100 to 6000 mPa · s, and particularly preferably 100 to 4000 mPa · s. When the viscosity at 25 ° C. exceeds 10,000 mPa · s, the resulting resin composition tends to have high viscosity and poor workability.
The molecular weight distribution (Mw / Mn) of the compound (A) is preferably 1.8 or less, more preferably 1.6 or less, particularly preferably 1.4 or less, and most preferably 1.2 or less. If the molecular weight distribution (Mw / Mn) is large, the resulting resin composition tends to be high in viscosity and poor in workability.
The compound (A) having the structure (characteristics) as described above is extremely different from conventionally used polyisoprene acrylate, urethane acrylate obtained from polyol, polyisocyanate, and hydroxyl group-containing (meth) acrylate. It has low viscosity, excellent workability, and has the ability to stably maintain optically excellent quality such as heat resistance, light resistance and moisture resistance over a long period of time.
[(B) Photopolymerization initiator]
Although the resin composition of this invention contains (B) photoinitiator as an essential component, there exists an effect that it can be hardened rapidly by light irradiation by containing a photoinitiator.

(B) Examples of the photopolymerization initiator include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2- Hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- ( 4-morpholinophenyl) butanone, oligo {2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone}, 2-hydroxy-1- {4- [4- (2-hydroxy- Acetophenones such as 2-methylpionyl) benzyl] phenyl} -2-methylpropan-1-one; Benzoins such as in, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3, 3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyl) Benzophenones such as (oxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthate Thioxanthones such as 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy) -3,4-dimethyl-9H-thioxanthone-9-one mesochloride, Oxy-phenyl-acetic acid 2- [2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester, oxy-phenyl-acetic acid 2- [2-hydroxy-ethoxy] ethyl ester, bis (2,4,4 6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and the like. Among them, acetophenones, oxy-phenyl-acetic acid 2- [2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester, and oxy-phenyl-acetic acid 2- [2-hydroxy-ethoxy] ethyl ester are preferable. It is.
As content of (B) photoinitiator in a resin composition, it is suitable that it is 0.1-10 mass% with respect to 100 mass% of resin compositions. When the content is 0.1% by mass or more, the resin composition can be sufficiently cured, and when the content is 10% by mass or less, generation of odor and coloring of the cured product can be sufficiently suppressed. More preferably, it is 0.3-5 mass%, More preferably, it is 1-5 mass%. Further, from the viewpoint of protecting the display device, for example, when the protective plate is provided with an ultraviolet cut layer, it is necessary to perform curing at a wavelength of 380 nm or more. In this case, the resin composition is 100% by mass. Acetophenones and / or oxy-phenyl-acetic acid 2- [2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester and / or oxy-phenyl-acetic acid 2- [2-hydroxy- 1.0 to 5% by mass of ethoxy] ethyl ester and 0 of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and / or 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. It is preferable to use 0.01 to 0.5% by mass in combination.

[(C) Plasticizer]
The optical ultraviolet resin curable resin composition of the present invention further includes (C) a plasticizer.
(C) A plasticizer refers to a compound having no radical polymerizability, specifically a compound having no (meth) acrylate group, such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate. , Diisononyl phthalate, di-2-ethylhexyl phthalate, dibenzyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, etc .; di-n-butyl adipate, diisobutyl adipate, dibutoxyethyl adipate, di-n -Adipates such as octyl adipate, diisooctyl adipate, diisononyl adipate, bis-2-ethylhexyl adipate, diisodecyl adipate; dibutyl sebacate, geo Sebacic acid esters such as tilsebacate and di-2-ethylhexyl sebacate; azelaic acid esters such as dihexyl azelate and dioctyl azelate; citric acids such as triethyl citrate, acetyl triethyl citrate and tri-n-butyl citrate Esters; glycolic acid esters such as methylphthalyl ethyl glycolate and ethyl phthalyl ethyl glycolate; trioctyl trimellitate, tri-n-octyl-n-decyl trimellitate, trialkyl trimellitic acid (C4- Trimellitic acid esters such as C11); ricinoleic acid esters such as methyl acetyl ricinoleate, butyl acetyl ricinolate and glycerin monoricinoleate; maleic acid esters such as di-n-butyl malate; monobutyl itacone Itaconic esters such as butyl oleate; oleic acid esters such as butyl oleate; esters such as tricresyl phosphate, trioctyl phosphate, triphenyl phosphate, phosphate esters such as trixylenyl phosphate, polyethylene glycol, Polyether polyols such as polypropylene glycol, ethylene oxide and propylene oxide copolymers; the above-mentioned polyether monool (a-1); polyolefin resins such as polyethylene, polypropylene, polystyrene; polymethyl methacrylate, polyacrylic acid, etc. (Meth) acrylic polymer having no polymerizable functional group or double bond in the side chain; polyester resin such as polyethylene terephthalate; polyamide resin such as nylon 6 or 6, polyisoprene, polybene Rubber-based polymers such as tadiene and polybutene; thermoplastic elastomers, terpene resins, terpene phenol resins, modified terpene resins, hydrogenated terpene resins, rosin ester resins, and the like can be used.

  The (C) plasticizer is appropriately selected according to the compatibility with the compound (A), the viscosity of the composition, and the like. Among these, the polyether polyol and the polyether monool (a-1) Is preferred. When these compounds are used as plasticizers, they can be used preferably because they can prevent fogging due to moisture absorption and have a humidity control action, so that the optical properties of the cured product and the durability of transparency can be improved. .

The (C) plasticizer is preferably blended in a proportion of 0 to 80% by mass of the entire resin composition excluding the photopolymerization initiator, more preferably 0 to 60% by mass, and even more preferably 10 to 50% by mass. %, Most preferably 20-50% by weight. By increasing the blending ratio of the (C) plasticizer in the resin composition, it is possible to reduce the curing shrinkage rate of the resulting resin composition, and it is possible to suppress a decrease in image forming performance of the display device. Moreover, the softness | flexibility of hardened | cured material can also be improved and shock-absorbing property also improves. On the other hand, when the blending amount of the plasticizer (C) exceeds 80% by mass, the plasticizer tends to be exuded on the surface of the cured product, and adheres to adherends such as display panels and protective plates. This is not preferable because it causes a decrease in performance.

[Other polymerizable components]
In the present invention, in addition to the above-described essential components (A) and (B) and the optional component (C), if necessary, a component that can be co-cured with the essential component (A) (other polymerizable components) ) May contain one or more of the following (meth) acrylate compounds and unsaturated compounds.
Although it does not specifically limit as a (meth) acrylate type compound, Methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t- Butyl (meth) acrylate, pentyl (meth) acrylate, neopentyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, unde (Meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, isomyristyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl Alkyl (meth) acrylates such as (meth) acrylate, nonadecyl (meth) acrylate, eicodecyl (meth) acrylate, n-lauryl (meth) acrylate, (meth) acryloylmorpholine, cyclohexyl (meth) acrylate, dicyclopentenyl ( (Meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, phenyl (meth) acrylate, benzyl ( Acrylate), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 1,4-butane Diol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, Hydroxyl group-containing (meth) acrylic acid ester compounds added with cyclic ester compounds such as ε-caprolactone, alkyl glycidyl ethers, allyl glycidyl ethers, glycidyl (meth) acrylates, etc. (Meth) acrylic acid is added to a compound obtained by addition reaction of a zyl group-containing compound and (meth) acrylic acid, tricyclodecane dimethanol di (meth) acrylate, 1,6 hexanediol di (meth) acrylate, and bisphenol A Bifunctional (meth) acrylates such as those reacted; trimethylolpropane tri (meth) acrylate, glycerin tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa ( Trifunctional or higher functional (meth) acrylates such as (meth) acrylate, and various (meth) acrylates modified by adding ethylene oxide and / or propylene oxide to the above (meth) acrylate, methoxy-polyethylene One end of alkyl glycol (meth) acrylate, ethoxy-polyethylene glycol (meth) acrylate, butoxy-polyethylene glycol (meth) acrylate, phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) acrylate, etc. is alkylated (Meth) acrylate with ethylene glycol or its polymer, methoxy-polypropylene glycol (meth) acrylate, ethoxy-polypropylene glycol (meth) acrylate, butoxy-polypropylene glycol (meth) acrylate, phenoxy-dipropylene glycol (meth) acrylate , Propylene glycol with one end alkylated, such as phenoxy-tripropylene glycol (meth) acrylate (Meth) acrylate, dimethylaminoethyl (meth) acrylate, amino group-containing (meth) acrylate such as diethylaminoethyl (meth) acrylate, (meth) acrylic acid, 2-acryloyloxyethyl succinic acid Carboxyl group-containing (meth) acrylates such as, a compound obtained by reaction of polyether polyol such as polypropylene glycol and (meth) acrylate (a-2) having an isocyanate group, urethane (meth) acrylate resin, polyester ( The reactive oligomer which has (meth) acrylates, such as a meth) acrylate type resin and an epoxy (meth) acrylate type resin, is mentioned.

The unsaturated compound is not particularly limited, but styrenes such as styrene, α-methylstyrene, vinyltoluene, and chlorostyrene; vinyl esters such as vinyl acetate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, and butyl vinyl ether. Allyl compounds such as allyl alcohol, allyl glycidyl ether, ethylene glycol monoallyl ether and propylene glycol monoallyl ether; N-substituted maleimides such as N-phenylmaleimide, N-cyclohexylmaleimide and N-isopropylmaleimide; N- N-vinyl compounds such as vinylpyrrolidone, N-vinylcaprolactam, N-vinyl-N-methylformamide, N-vinylimidazole, N-vinylacetamide, 2- (vinyl) (meth) acrylate Siethyl, 3-vinyloxyethyl (meth) acrylate, 2-vinyloxypropyl (meth) acrylate, 1-methyl-2-vinyloxyethyl (meth) acrylate, 4-vinyloxybutyl (meth) acrylate, (meth) acrylic acid 6 -Vinyloxyhexyl, (meth) acrylic acid 4-vinyloxycyclohexyl, (meth) acrylic acid 4-vinyloxymethylcyclohexylmethyl, (meth) acrylic acid 2- (2-vinyloxyethoxy) ethyl, (meth) acrylic acid 2- (2-vinyloxyisopropoxy) propyl, 2- (2- (2-vinyloxyethoxy) ethoxy) ethyl (meth) acrylate, diallyl isophthaldiphenate, diallyl phthalate diallyl, triallyl cyanurate, triallyl isocyanurate Allyl ester monomers such as tri Vinyl ether monomers such as tylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, hydroxybutyl vinyl ether, dodecyl vinyl ether; trimethylolpropane diallyl ether, pentaerythritol triallyl ether, allyl glycidyl ether, allyl ether of methylol melamine, adipine of glycerin diallyl ether Allyl ether monomers such as allyl ethers of acid esters, allyl acetals, methylol glyoxalureins; Maleate ester monomers such as diethyl maleate and dibutyl maleate; Fumarate monomers such as dibutyl fumarate and dioctyl fumarate Is mentioned.
Among these, as other polymerizable components, compounds obtained by reaction of polyether polyols such as polypropylene glycol and (meth) acrylate (a-2) having an isocyanate group are preferable. By using these compounds, the elongation percentage of the resulting cured product is improved and the impact resistance is increased.

The content of other polymerizable components is preferably blended at a rate of 0 to 50% by mass of the entire resin composition, more preferably 10 to 50% by mass, still more preferably 20 to 50% by mass, and most preferably 30-50% by mass. By using a (meth) acrylate compound and / or a vinyl compound, the viscosity and workability of the resulting resin composition can be adjusted. Furthermore, physical properties such as heat resistance, light resistance, and transparency can be adjusted. On the other hand, a usage ratio exceeding 50% by mass is not preferable because the curing shrinkage rate increases and the image forming performance of the display device decreases.

[Other ingredients]
Furthermore, the ultraviolet curable resin composition of the present invention includes a thermosetting catalyst, an ultraviolet absorber, a polymerization inhibitor, a leveling agent, a thickener, a thickener, and a thixotropy imparting agent as long as the effects of the present invention are not impaired. Further, a defoaming agent or the like may be included.

  Specific examples of the thermosetting catalyst include benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy octoate, t- Organic peroxides such as butyl peroxybenzoate, cumene hydroperoxide, cyclohexanone peroxide, dicumyl peroxide, bis (4-t-butylcyclohexyl) peroxydicarbonate; azobisisobutyronitrile, 2-phenylazo- Examples include azo compounds such as 2,4-dimethyl-4-methoxyvaleronitrile, but are not particularly limited. These thermosetting catalysts may be used alone or in combination of two or more. The addition amount of the curing catalyst with respect to the monomer component is not particularly limited.

  A commercially available ultraviolet absorber may be used. For example, salicylic acid esters such as benzotriazoles, benzoates, cyanoacrylates, benzophenones, phenyl salicylate, pt-butylphenyl salicylate, p-octylphenyl salicylate; TINUVIN 770, 123, 144 622 (above, product name of Ciba Geigy), SANOL LS-770,765,292, 2626 (above, product name of Sankyo Co., Ltd.), Adekastab LA-52,57,62 (above, product of Asahi Denka Co., Ltd.) Hindered amines such as name) can be used.

The other components as described above are preferably 0 to 30% by mass in the resin composition, more preferably 0 to 20% by mass, and particularly preferably 0 to 10% by mass.
(Preparation of resin composition)
The resin composition of the present invention can be prepared by mixing the above components and is usually in the form of a viscous liquid. Specifically, the viscosity is 200 to 10000 mPa · s, preferably 200 to 8000 mPa · s, more preferably 300 to 6000 mPa · s, particularly preferably 500 to 8000 mPa · s, and most preferably 500 to 6000 mPa · s. If the viscosity is too high, handling properties such as workability (fillability) are reduced. The viscosity of the resin composition can be calculated using a B-type viscometer (model “RB80L” manufactured by Toki Sangyo Co., Ltd.) under a temperature of 25 ° C.

  The resin composition of the present invention is preferably solventless. This is because the diluting solvent needs to be volatilized after injection, and the residual solvent can cause a decrease in the photopolymerization speed, and can cause a decrease in the optical properties and durability of the resulting cured product.

Therefore, when the resin composition is obtained in a state containing a solvent, it is preferable to remove the solvent by reduced pressure, distillation or the like.
<Hardened product>
The resin composition of the present invention having the above composition can be cured by ultraviolet irradiation. The term “curing” as used herein means that there is no fluidity.
The wavelength of the ultraviolet rays used may be in the range of 150 to 450 nm. Examples of the light source that emits such a wavelength include sunlight, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a gallium lamp, a xenon lamp, a flash type xenon lamp, and a carbon arc lamp. Irradiation integrated light quantity is preferably 0.1~10J / cm ^2, more preferably 0.2~5J / cm ^2, more preferably in the range of 0.3~3J / cm ^2.
The cured product of the present invention may be obtained by using both curing by light irradiation and curing by heating. In this case, infrared light, far infrared light, hot air, high-frequency heating, or the like may be used together with the light source described above. The heating temperature may be appropriately adjusted according to the decomposition temperature of the thermosetting catalyst, the type of base material used, and the like, and is not particularly limited, but is preferably 50 to 150 ° C, more preferably 50 to 100 ° C. More preferably, it exists in the range of 60-90 degreeC. The heating time may be appropriately adjusted according to the decomposition temperature or coating thickness of the thermosetting catalyst, and is not particularly limited, but is preferably 1 minute to 12 hours, more preferably 10 minutes to 6 hours, Preferably, it is within the range of 10 minutes to 3 hours.
The cured product of the present invention may be obtained by using both curing by light irradiation and curing by electron beam irradiation. In this case, the acceleration voltage is preferably 0 to 500 kV, more preferably 20 to 300 kV, and even more preferably 30 to 200 kV. The irradiation amount is preferably in the range of 2 to 500 kGy, more preferably 3 to 300 kGy, and still more preferably 4 to 200 kGy.

The cured product of the present invention has a cure shrinkage of 2% or less, more preferably 1.5% or less, further preferably 1.0% or less, and most preferably 0.7% or less. By setting the curing shrinkage rate to 2% or less, it is possible to prevent a decrease in image forming performance of the display device. In addition, the value obtained by the specific gravity measurement described in the below-mentioned Example is employ | adopted for hardening shrinkage.

The cured product of the present invention has a C hardness of 75 or less, more preferably 50 or less, further preferably 30 or less, and most preferably 25 or less. When the C hardness is 75 or less, the impact resistance is improved. For the C hardness, a value obtained using an ASKER durometer C-type hardness meter based on JIS K7312 in an atmosphere of 25 ° C. is adopted.

The cured product of the present invention preferably has an elongation of 50% or more, more preferably 100% or more, further preferably 150% or more, and most preferably 200% or more. By setting the elongation rate to 50% or more, the impact resistance is improved. In addition, the value obtained by the tensile test on the conditions described in the below-mentioned Example is employ | adopted for elongation rate.

The cured product of the present invention preferably has a light transmittance of 400 nm at a thickness of 0.3 mm of 88% or more, more preferably 89% or more, still more preferably 90% or more, and most preferably 91% or more. By setting the light transmittance to 88% or more, it is possible to prevent a decrease in image forming performance of the display device. The light transmittance at 400 nm is a value measured using a spectrophotometer.

The cured product of the present invention has a turbidity at a thickness of 0.3 mm of 0.8% or less, more preferably 0.6 or less, further preferably 0.5% or less, and most preferably 0.4 or less. It is. By setting the turbidity to 0.8 or less, it is possible to prevent a decrease in image forming performance of the display device. In addition, the value measured based on JISK7136 is employ | adopted for turbidity.

<Display device>
The optical ultraviolet curable resin composition of the present invention that can obtain the cured product as described above includes a display panel and a protective plate of an electronic terminal such as a mobile phone, an electronic book, and a touch panel, a display device such as a liquid crystal television and a plasma television. It can be used as a space filler. The optical ultraviolet curable resin composition of the present invention only needs to contain at least a display panel and a protective plate. For example, one or more functional layers such as a touch panel are provided between the display panel and the protective plate. It can also be used for a display device provided with two or more layers.

  Specifically, FIG. 1 is a schematic cross-sectional view of a liquid crystal display device having a cured product 4 of the optical ultraviolet curable resin composition of the present invention between the display panel 1 and the protective plate 2 (gap 3). is there. In the liquid crystal display device, a cured product 4 of the optical ultraviolet curable resin composition of the present invention is interposed between the display panel 1 and the protective plate 2, and the cured product 4 is in close contact with the display panel 1 and the protective plate 2. The display panel 1 and the protective plate 2 are laminated and integrated. The protective plate 2 is a glass plate having the same size as the image display unit 1, a plastic plate such as (meth) acrylic resin (for example, PMMA), polycarbonate resin (PC), or triacetyl cellulose (TAC), a sheet, or a film The protective plate 2 may further have black printing or the like on the outer peripheral portion, or may have an antireflection layer, a hard coat layer, or the like on the surface portion. In addition, the display panel 1 in a liquid crystal display device generally has a polarizing plate (polarizing filter) / transparent plate (glass plate, plastic plate) / liquid crystal material sandwiched between transparent electrodes / transparent plate (glass plate, plastic plate). The cured product 4 of the optical ultraviolet curable resin composition of the present invention is at least the polarizing plate (polarizing filter) in the outermost layer of the display panel 1. ) Can also be adhered (adhered). That is, the polarizing plate (polarizing filter) is usually formed in a form in which polyvinyl alcohol (PVA) dyed with iodine is sandwiched between two sheets of triacetyl cellulose (TAC), and the TAC surface is untreated and hard-coated. In addition, the cured product 4 of the optical ultraviolet curable resin composition of the present invention can be adhered (adhered) to these materials. The display panel 1 is a liquid crystal display panel in the case of a liquid crystal display device, a plasma panel in the case of a plasma display device, and an organic EL panel in the case of an organic EL display device.

FIG. 2 is a schematic cross-sectional view of a liquid crystal display device mounted with a touch panel using the cured product 4 of the optical ultraviolet curable resin composition of the present invention. In the liquid crystal display device, the touch panel 5 is disposed on the display surface of the display panel 1 with a predetermined interval 6a, and the protective plate 2 is disposed with a predetermined interval 6b. The touch panel 5 is formed with the predetermined intervals 6a and 6b. The cured resin (resin layer) 7 and 7 'is formed by ultraviolet curing, and the image display unit 1, the touch panel 5, and the protective plate 2 are laminated and integrated. The touch panel 5 has a transparent conductive layer printed on the back surface (surface on the display unit 1 side) of two transparent plates made of glass or polyethylene terephthalate, for example, and is pressed by an operator's finger or pen. When they come into contact with each other, a conductive state is established. In the figure, reference numeral 8 denotes a black print layer printed on the outer peripheral edge of the protective plate 2.
Similarly to the case of FIG. 1, the protective plate 2 may have, for example, an antireflection layer, a hard coat layer, or the like on the surface portion.

As described above, the display device in which the cured product of the optical ultraviolet curable resin composition of the present invention is interposed is based on the characteristics of the resin composition of the present invention. Since it is filled and cured, there is very little display unevenness due to voids, irregularities and steps. Moreover, the cured product is soft, excellent in shock absorption, and can maintain excellent transparency against environmental changes such as high temperature, high humidity, and light. There is little reduction in definition.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to description of a following example.

In the examples, “part” means a weight basis unless otherwise specified.
〔Evaluation methods〕
(1) Composition Viscosity The obtained resin composition was measured using a B-type viscometer (model “RB80L”, manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25 ° C.
(2) Curing shrinkage (%)
The specific gravity of the resin composition and the specific gravity of the cured product obtained by curing the resin composition at 25 ° C. were measured and obtained from the following calculation.

Curing shrinkage (%) = (cured product specific gravity−resin composition specific gravity) / cured product specific gravity × 100
(3) Hardness value Based on JIS K7312, a sheet-shaped test piece (width 17 mm × length 45 mm × thickness 4 mm) obtained by curing the obtained resin composition using an ASKER durometer C-type hardness meter ) Was measured. The value after 15 seconds from the start of measurement was taken as the hardness value.
(4) Growth rate (%)
Using a sheet-like test piece (width 4 mm × length 20 mm × thickness 1 mm) obtained by curing the obtained resin composition, a tensile test at an ambient temperature of 25 ° C. and a tensile speed of 0.1 mm / s. And the elongation was calculated according to the following formula. In the formula, L is the displacement length until breakage, and L ₀ is the length of the sheet before the test.

Elongation rate (%) = L / L ₀ × 100
(5) Light transmittance (%)
Using a sheet-like test piece (width 50 mm × length 50 mm × thickness 0.3 mm) obtained by curing the obtained resin composition, the light transmittance at 400 nm was measured with a spectrophotometer (form “UV- 3100 ", manufactured by Shimadzu Corporation).
(6) Turbidity (%)
It measured based on JISK7136 using the sheet-like test piece (width 50mm x length 50mm x thickness 0.3mm) obtained by hardening the obtained resin composition.
(7) Heat resistance A test piece (width 50 mm × length 70 mm × thickness 1 mm) sandwiched between glass plates obtained by curing the obtained resin composition was heated in an oven at 100 ° C. for 500 hours. . The discoloration after heating was visually confirmed and evaluated in the following three stages. A glass plate having a thickness of 3 mm was used.

○: No discoloration was observed Δ: Slight discoloration ×: Large discoloration (8) Light resistance Test piece sandwiched between glass plates obtained by curing the obtained resin composition (width 50 mm × length 70 mm × thickness 1 mm) was irradiated with light at 500 MJ / m ² using a metering weather meter (model “M6T”, manufactured by Suga Test Instruments Co., Ltd., irradiation intensity 0.5 kW / m ² ). The discoloration after irradiation was visually confirmed and evaluated in the following three stages. A glass plate having a thickness of 3 mm was used.
○: No discoloration is observed Δ: Slight discoloration ×: Large discoloration (9) Moisture resistance Sheet-like test piece obtained by curing the obtained resin composition (width 50 mm × length 70 mm × thickness) 1 mm) was held in a thermo-hygrostat (temperature 80 ° C., humidity 90% RH) for 100 hours, and then the turbidity of the sheet was visually confirmed and evaluated in the following three stages.

○: No turbidity △: Slightly turbid ×: Turbidity (10) Workability (fillability)
200 g of the obtained resin composition was dropped in the vicinity of the center on a glass plate having a width of 300 mm, a length of 200 mm, and a thickness of 3 mm having a 1 mm thick silicone spacer on four sides in an atmosphere of 25 ° C., and the same size thereon. The glass plate was covered. Next, an average time (n = 3) until the resin composition was filled was determined and evaluated in the following four stages.

: Less than 60 seconds ○: More than 60 seconds and less than 180 seconds Δ: More than 180 seconds and less than 500 seconds ×: More than 500 seconds (11) Removability (repair property)
A test piece (width 50 mm × length 70 mm × thickness 0.3 mm) sandwiched between glass plates obtained by curing the obtained resin composition was prepared, and the sheet-like cured product was peeled from the glass plate. The state of time was evaluated in the following three stages. A glass plate having a thickness of 3 mm was used.
○: The cured sheet is not damaged and can be easily peeled. Δ: Some force is required, but the cured sheet is not damaged and can be peeled. ×: The cured sheet is damaged or cannot be peeled (12) Image forming property A resin composition obtained by disposing a silicone spacer having a thickness of 0.1 mm on a liquid crystal module from which a front protective cover of a commercially available mobile phone (Sharp SH-09B) was removed was filled. Next, a 1 mm glass plate was mounted thereon. Next, it was cured by irradiation with ² J / cm ² light with a high-pressure mercury lamp to obtain a mobile phone having a laminated structure of liquid crystal module / resin layer / front protective glass. Next, the power of the obtained mobile phone was turned on, and the evaluation of images was evaluated in the following three stages.
○: There is no image unevenness Δ: There is very little image unevenness ×: There are many image unevennesses (13) Impact resistance absorption The state of being sandwiched between glass plates obtained by curing the obtained resin composition A test piece (width 50 mm × length 70 mm × thickness 0.3 mm) was prepared, and the height at which the upper glass plate was damaged when a 200 g steel ball was dropped on the test piece was determined and evaluated in the following four stages. A glass plate having a thickness of 3 mm was used.

: 500 mm or more ○: 300 mm or more and less than 500 mm Δ: 200 mm or more and less than 300 mm ×: less than 200 mm

Production Example 1 (Synthesis of P-1)
In a reactor equipped with a thermometer, a cooler, a gas introduction tube, and a stirrer, the number average molecular weight Mn is 1200 (molecular weight distribution (Mw / Mn) = 1.06) as polyether monool (a-1). A polypropylene glycol monobutyl ether (manufactured by Sanyo Chemical Co., Ltd., product number Newpol LB285) was charged with 300 g, methoquinone 0.15 g and dibutyltin dilaurate 0.15 g, and the mixture was heated to 70 ° C. while stirring. Next, 35.8 g of 2-acryloyloxyethyl isocyanate (manufactured by Showa Denko KK, product number Karenz AOI) as the (meth) acrylate (a-2) having an isocyanate group (1 with respect to the hydroxyl group in the polyether monool) 0.0 equivalent) was added dropwise over 2 hours. After completion of the dropping, the temperature was maintained at 80 ° C. for 3 hours to complete the reaction, and a compound having an acrylate group (referred to as “P-1”) was obtained. The isocyanate reaction rate determined by infrared spectroscopy was 98%. Moreover, the viscosity in 25 degreeC was 200 mPa * s. Further, by GPC measurement, the number average molecular weight (Mn) was 1480, and the molecular weight distribution (Mw / Mn) was 1.09.

Production Example 2 (Synthesis of P-2)
300 g of polypropylene glycol monobutyl ether (manufactured by Sanyo Chemical Co., Ltd., product number Newpol LB685) having a number average molecular weight Mn of 1900 (molecular weight distribution (Mw / Mn) = 1.06) as polyether monool (a-1), isocyania As the (meth) acrylate (a-2) having a nate group, 22.6 g of 2-acryloyloxyethyl isocyanate (manufactured by Showa Denko KK, product number Karenz AOI) (1.0 equivalent to the hydroxyl group in the polyether monool) A compound having an acrylate group (referred to as “P-2”) was obtained in the same manner as in Production Example 1 except that The isocyanate reaction rate determined by infrared spectroscopy was 99%. Moreover, the viscosity in 25 degreeC was 360 mPa * s. Further, by GPC measurement, the number average molecular weight (Mn) was 2200, and the molecular weight distribution (Mw / Mn) was 1.09.

Production Example 3 (Synthesis of P-3)
300 g of polypropylene glycol monobutyl ether (manufactured by Sanyo Chemical Co., product number Newpol LB3000) having a number average molecular weight Mn of 2800 (molecular weight distribution (Mw / Mn) = 1.05) as the polyether monool (a-1), isocyania 15.3 g of 2-acryloyloxyethyl isocyanate (manufactured by Showa Denko KK, product number Karenz AOI) as a (meth) acrylate having a nate group (a-2) (1.0 equivalent to the hydroxyl group in the polyether monool) A compound having an acrylate group (referred to as “P-3”) was obtained in the same manner as in Production Example 1, except that The isocyanate reaction rate determined by infrared spectroscopy was 99%. Moreover, the viscosity in 25 degreeC was 2000 mPa * s. Further, by GPC measurement, the number average molecular weight (Mn) was 3100, and the molecular weight distribution (Mw / Mn) was 1.08.

Production Example 4 (Synthesis of P-4)
As the polyether monool (a-1), a random copolymer type polyether monool (Sanyo Kasei Co., Ltd.) having a number average molecular weight Mn of 3800 (molecular weight distribution (Mw / Mn) = 1.06) 300 g of product number Newpol 50HB5100), 11.3 g of 2-acryloyloxyethyl isocyanate (product number Karenz AOI, manufactured by Showa Denko KK) as a (meth) acrylate (a-2) having an isocyanate group (polyether monool) A compound having an acrylate group (referred to as “P-4”) was obtained in the same manner as in Production Example 1, except that 1.0 equivalent) was used relative to the hydroxyl group therein. The isocyanate reaction rate determined by infrared spectroscopy was 99%. Moreover, the viscosity in 25 degreeC was 3200 mPa * s. Further, by GPC measurement, the number average molecular weight (Mn) was 4100, and the molecular weight distribution (Mw / Mn) was 1.08.
Production Example 5 (Synthesis of PPG-A)
300 g of polypropylene glycol (manufactured by Asahi Glass Co., product number Preminol 4011) having a number average molecular weight Mn of 11000 (molecular weight distribution (Mw / Mn) = 1.08), which is a polyether polyol, (meth) acrylate having an isocyanate group (a -2) As in Production Example 1, except that 7.7 g of 2-acryloyloxyethyl isocyanate (manufactured by Showa Denko KK, product number Karenz AOI) (1.0 equivalent to the hydroxyl group in the polyether polyol) was used. Thus, a compound having an acrylate group (referred to as “PPG-A”) was obtained. The isocyanate reaction rate determined by infrared spectroscopy was 98%. Moreover, the viscosity in 25 degreeC was 4900 mPa * s. Further, by GPC measurement, the number average molecular weight (Mn) was 11300, and the molecular weight distribution (Mw / Mn) was 1.10.

Production Example 6 (A-1 synthesis)
In a reactor equipped with a thermometer, a cooler, a gas inlet tube, and a stirrer, 100 g of butyl acrylate, 2-ethylhexyl silylate, 100 g, 10 g of acrylic acid, 0.8 g of chain transfer agent n-dodecyl mercaptan, toluene as a solvent After charging 500 parts, the inside of the reactor was replaced with nitrogen gas. Next, while stirring the above mixture, the temperature was raised to 85 ° C., and as a polymerization initiator, 1 part of 2,2′-azobismethylbutyronitrile was dissolved in 300 g of toluene over 5 hours. The solution was added dropwise to carry out a polymerization reaction.

Next, the reaction temperature was maintained at 95 ° C. for 3 hours, and 0.3 g of methoquinone was added to obtain an acrylic polymer solution. Next, toluene was distilled off under reduced pressure to obtain a colorless transparent viscous liquid acrylic polymer (referred to as “A-1”). Moreover, the viscosity in 25 degreeC was 50700 mPa * s. The resulting acrylic polymer had a number average molecular weight Mn of 6000 and a molecular weight distribution (Mw / Mn) of 5.6.

Production Example 7 (UA-1 synthesis)
In a reactor equipped with a thermometer, a cooler, a gas introduction pipe, a dropping line and a stirrer, polypropylene glycol (manufactured by Adeka Co., Ltd.) having a number average molecular weight Mn of 3000 (molecular weight distribution (Mw / Mn) = 1.05) (Product number P-3000) 150 g, methoquinone 0.05 g, dibutyltin dilaurate 0.05 g were added, and the temperature was raised to 80 ° C. After a fixed temperature, 17 g of hexamethylene diisocyanate was added dropwise over 1 hour, and after completion of the addition, a temperature of 80 ° C. was maintained for 5 hours. Next, a mixture of 34 g Plaxel FA2D (manufactured by Daicel Chemical Industries, ε-caprolactone 2-mol adduct of 2-hydroxyethyl acrylate) and 0.01 g of methoquinone was added dropwise over 2 hours. After completion of the dropwise addition, a temperature of 80 ° C. was maintained for 15 hours to obtain urethane acrylate (referred to as “UA-1”) having an average of two acrylates. The viscosity of the obtained UA-1 at 25 ° C. was 315000 mPa · s. Further, by GPC measurement, the number average molecular weight (Mn) was 3500, and the molecular weight distribution (Mw / Mn) was 6.6.

Example 1
[Preparation of UV-curable resin composition for optics and preparation of cured product]
Mixing with 100 parts of the compound (P-1) having an acrylate synthesized in Production Example 1 and 2 parts of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, product number Irgacure 184D), a display panel and a protective plate of the display device are mixed. An optical ultraviolet curable resin composition (hereinafter referred to as a composition) used for stacking and integration was prepared. Next, the viscosity, workability (fillability), and image moldability of the composition were evaluated by the above methods.

Next, the obtained composition was dropped on a glass plate having a predetermined size in which silicone spacers having a predetermined thickness were arranged on four sides, and the glass plate was filled. Next, a glass plate of the same size was put on the top. Next, it is cured by irradiation with ² J / cm ² light with a high-pressure mercury lamp, and the cured product layer of the composition is peeled from the test piece having a laminated structure of glass plate / cured product layer / glass plate or a glass plate. A test piece was prepared. The prepared test pieces were evaluated for curing shrinkage, hardness value, elongation, light transmittance, turbidity, heat resistance, light resistance, moisture resistance, and removability (repairability) based on the above evaluation measurement method.
The evaluation results are shown in Table 1.

Examples 2 to 15 and Comparative Examples 1 to 5
In the same manner as in Example 1, the components were mixed and stirred at the ratios shown in Table 1 to obtain compositions (2) to (15) and comparative compositions (1) to (5). Then, it replaced with the composition (1) in Example 1, and obtained the test piece like Example 1 except having used each of these compositions. The obtained composition and test piece were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Abbreviations in Table 1 are as follows.
HPMA: 2-hydroxypropyl methacrylate (trade name “Light Ester HOP”, manufactured by Kyoeisha Chemical Co., Ltd.)
HDDA: 1,6-hexanediol diacrylate (trade name “Light acrylate 1,6HD-A”, manufactured by Kyoeisha Chemical Co., Ltd.)
UC203: Polyisoprene rubber having methacrylate (trade name “Kuraprene UC203”, manufactured by Kuraray Co., Ltd.)
BAC45: Polybutadiene rubber with acrylate (trade name “BAC45”, manufactured by Osaka Organic Chemical Co., Ltd.)
BA: butyl acrylate 2EHA: 2-ethylhexyl acrylate P-1: compound P-2 having an acrylate group obtained in Production Example 1: compound P-3 having an acrylate group obtained in Production Example 2: obtained in Production Example 3 Compound P-4 having an acrylate group: Compound PPG-A having an acrylate group obtained in Production Example 4: Compound A-1 having an acrylate group obtained in Production Example 5: Acrylic polymer UA- obtained in Production Example 6 1: Urethane acrylate terpene resin A obtained in Production Example 7: Hydrogenated terpene resin (trade name “Clearon P85”, manufactured by Yasuhara Chemical Co., Ltd.)
DIDA: Diisodecyl adipate (Brand name “Vinizer 50”, manufactured by Kao Corporation)
P1000: Polypropylene glycol (trade name “P-1000”, manufactured by Adeka)
Liquid rubber A: Polybutene (trade name “VL-100”, manufactured by JX Nippon Oil & Energy Corporation)
Irg184: 1-hydroxy-cyclohexyl-phenyl-ketone (trade name “Irgacure 184”, manufactured by Ciba Specialty Chemicals)

From the results of Examples and Comparative Examples described above, the ultraviolet curable resin composition for optical use of the present invention is (A) a polyether monool (a-1) and a (meth) acrylate having an isocyanate group (a- 2) A compound obtained by reaction with (2), and (B) a photopolymerization initiator, whereby a cured product and a display device obtained by curing the optical ultraviolet curable resin composition are transparent, It has been confirmed that it has an advantageous effect in that various properties such as heat resistance, light resistance, moisture resistance, workability, removability, impact resistance absorption, etc. can be exhibited at the same time in a balanced manner. It was.

  Since the optical ultraviolet curable resin composition of the present invention is in a liquid state, it can be applied to display devices of various sizes, has excellent versatility, and has optical characteristics against environmental changes such as light, heat, and moisture. UV light used between the display panel and the protective plate of various display devices because it can maintain the workability, re-peelability, shock absorption, workability, etc. at the same time in a balanced manner. It is suitable as a curable resin composition.

Claims (7)

An ultraviolet curable resin composition used for laminating and integrating a display panel and a protective plate of a display device, the ultraviolet curable resin composition,
(A) Compound obtained by reaction of polyether monool (a-1) and (meth) acrylate (a-2) having an isocyanate group,
(B) An optical ultraviolet curable resin composition comprising a photopolymerization initiator. 2. The optical ultraviolet curable resin composition according to claim 1, wherein the polyether monool (a-1) has a number average molecular weight of 1000 or more. The said ultraviolet-curable resin composition for optics of Claim 1 or 2 with which the said polyether monool (a-1) contains polyoxypropylene monoether. Furthermore, (C) Plasticizer is included, The ultraviolet curable resin composition for optics in any one of Claims 1-3 characterized by the above-mentioned. The optical ultraviolet curable resin composition according to any one of claims 1 to 4, wherein the viscosity at 25 ° C is 200 to 10,000 mPa · s. Hardened | cured material obtained by hardening | curing the ultraviolet curable resin composition for optics in any one of Claims 1-5 by ultraviolet irradiation. A display device comprising a cured product of the ultraviolet curable resin composition for optics according to claim 1.

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