JP5764040B2 - Optical UV-curable resin composition, cured product, and display device - Google Patents

Description

  The present invention attaches each member such as a display panel, a protective plate, and a sheet-like functional member such as a touch panel in an image display device such as a mobile phone, a liquid crystal television, a plasma television, an electronic book, and a liquid crystal display built-in touch panel device. The present invention relates to an optical ultraviolet curable resin composition to be used, a cured product thereof, and a display device using the cured product.

  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 (meth) acrylic pressure-sensitive adhesive having a gel fraction of 50 to 90% by weight and a storage elastic modulus of a predetermined value or less (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 acid 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 handling of large sheets having a predetermined adhesiveness and viscoelasticity for absorbing shock is not easy. 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.

  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.

  Furthermore, if wrinkles occur on the attached transparent sheet or air is caught between the adherend and the adherend, it is necessary to reattach the transparent sheet. Moreover, the performance (removability or repairability) that can be reattached is also strongly required.

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 circumstances as described above, and the object of the present invention is to deal with display devices of various sizes and display devices having irregularities on the adherend surface. It is a liquid resin composition excellent in heat resistance, heat resistance, light resistance, moisture resistance, that is, the performance of stably maintaining optically superior quality over a long period of time, and adhesion, removability, resistance An object of the present invention is to provide an ultraviolet curable resin composition excellent in shock absorption, a cured product obtained by curing the resin composition, and a display device using the cured product.

In other words, the optical ultraviolet curable resin composition of the present invention is used to attach at least any two selected from the group consisting of a display panel, a protective plate, and a sheet-like functional member used in a display device. An ultraviolet curable resin composition used for the above purpose, wherein the ultraviolet curable resin composition comprises (A) a polyether polyol (a-1) and an α, β unsaturated carbonyl having a functional group that reacts with a hydroxyl group. A polymer having an acryloyl group or a methacryloyl group and a molecular weight distribution (Mw / Mn) of 1.2 or less , obtained by reaction with the compound (a-2); and (B) a photopolymerization initiator. And

  The functional group is preferably an isocyanate group or a carboxyl group, and the unsaturated carbonyl group constituting the α, β unsaturated carbonyl compound (a-2) is preferably an acryloyl group or a methacryloyl group, Specifically, 2-acryloyloxyethyl isocyanate or 2-methacryloyloxyethyl isocyanate; or acrylic acid or methacrylic acid.

The polyether polyol (a-1) preferably has a number average molecular weight of 3000 or more, and preferably contains polypropylene glycol. Moreover, it is preferable that molecular weight distribution (Mw / Mn) of the said polyether polyol (a-1) is 1.1 or less.

  The optical ultraviolet curable resin composition of the present invention may contain (C) a plasticizer. As the (C) plasticizer, a rosin ester resin or a polyether polyol is preferably used.

  The optical ultraviolet curable resin composition of the present invention preferably further contains (D) a polymerizable component having a molecular weight of 1000 or less, and the polymerizable component is a (meth) acrylate compound, particularly a homopolymer. A monofunctional (meth) acrylate compound having a glass transition temperature of −50 ° C. or higher is preferable.

  When the optical ultraviolet curable resin composition of the present invention contains (C) a plasticizer and (D) a polymerizable component having a molecular weight of 1000 or less, the total content of (C) the plasticizer and (D) the polymerizable component. Is preferably 75% by mass or less of the total content of the component (A), the component (C), and the component (D).

  The optical ultraviolet curable resin composition of the present invention preferably has a viscosity at 25 ° C. of 300 to 15000 mPa · s.

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

  The display device of the present invention is a display device comprising a display panel and a protective plate and / or a sheet-like functional member, a combination of the display panel and a protective plate or a sheet-like functional member, or the protective plate and a sheet-like member. At least one of the combinations with the functional member is pasted with the cured product of the present invention. The display device may include a plurality of sheet-like functional members. In this case, at least the first sheet-like functional member and the second sheet-like functional member are attached with the cured product of the present invention. It is preferable.

  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 0.3 mL. Using a Tosoh column TSK-gel SuperHM-H and one TSK-gel SuperH2000, the gel permeation chromatography (GPC) apparatus manufactured by Tosoh HLC-8220GPC is used. It is a converted value.

  The optical ultraviolet curable resin composition of the present invention is a liquid with low viscosity and excellent workability, and the cured product obtained by ultraviolet irradiation is excellent in heat resistance, light resistance and moisture resistance, that is, optically. Excellent performance for maintaining quality over a long period of time, adhesion, removability, and shock absorption. Therefore, it is suitable as a transparent polymer material used for adhering each member of a display panel, a protective plate, and a sheet-like functional member which are constituent members of 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. FIG. 3 is a schematic cross-sectional view showing another embodiment of a display device using the cured product of the present invention. FIG. 4 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 simply referred to as “resin composition”) is selected from the group consisting of a display panel, a protective plate, and a sheet-like functional member used in a display device. It is used for adhering at least two of them, and as a main component, (A) a polyether polyol (a-1) and an α, β unsaturated carbonyl compound having a functional group that reacts with a hydroxyl group (a- 2) a polymer obtained by reaction with (2), and (B) a photopolymerization initiator, preferably (C) a plasticizer, and / or (D) a polymerizable component having a molecular weight of 1000 or less, and / or (E) Contains an additive.

[(A) Polymer obtained by reaction of polyether polyol (a-1) and unsaturated carbonyl compound (a-2)]
(1) Polyether polyol (a-1)

  The polyether polyol (a-1) is not particularly limited as long as it is a polyether having an oxyalkylene group (—R—O—) as a repeating unit and having two or more hydroxyl groups.

The oxyalkylene group (—R—O—) constituting the main skeleton of the polyether polyol (a-1) is an oxyalkylene in which R is a linear and / or branched alkylene group having 1 to 14 carbon atoms. is preferably a group _{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 -Etc. are mentioned. The polyether polyol (a-1) may have two or more oxyalkylene groups, and in addition to the oxyalkylene group as a repeating unit, a polyol used as an initiator for polyether synthesis. The reaction residue of the compound, for example, bisphenol A residue, ethylenediamine residue, lactone residue and the like may be contained.

  A commercially available product may be used as the polyether polyol (a-1). Examples of commercially available products include Adeka's trade name “Adeka Polyether”, a PEG series corresponding to polyethylene glycol, a P series corresponding to polypropylene glycol, and a BPX series corresponding to a polypropylene glycol adduct of bisphenol A. G series corresponding to polypropylene glycol adduct of glycerin, T series corresponding to polypropylene glycol adduct of trimethylolpropane, EDP series tetraol corresponding to polypropylene glycol adduct of ethylenediamine, polypropylene glycol adduct of sorbitol Corresponding SP series, R series corresponding to polypropylene glycol adduct of sucrose, S corresponding to polypropylene glycol adduct to sucrose and glycerin Series, PR series corresponding to random copolymer of ethylene oxide and propylene oxide (PO-EO random copolymer), GR series corresponding to PO-EO random copolymer adduct of glycerin, EM corresponding to PO-EO copolymer adduct of bisphenol A Series, CM series in which propylene oxide-ethylene oxide block copolymer is added to propylene glycol can be used. Further, polycaprolactone diol, polycaprolactone triol, polycarbonate diol and the like mentioned under the trade name “Placcel” manufactured by Daicel Chemical Industries, Ltd. can also be used.

As the oxyalkylene group serving as a repeating unit constituting the main skeleton of the polyether polyol (a-1), —CH ₂ CH ₂ O— and —CH ₂ CH (CH ₃ ) O— are preferable, and —CH ₂ CH (CH ₃ ) O— is particularly preferred. Accordingly, preferred polyether polyol (a-1) includes polyethylene glycol and polypropylene glycol, and more preferred is polypropylene glycol.

  Further, the content ratio of the repeating unit (polyether part) in the polyether polyol (a-1) is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more. is there. When the content ratio of the polyether part is less than 80% by mass, the content of the polyether part in the polymer (A), which is a reaction product with the hydroxyl-reactive unsaturated carbonyl compound (a-2), is low. It tends to be high, and the workability of the finally prepared resin composition tends to be poor.

  Further, the molecular weight of the polyether polyol (a-1) is preferably a number average molecular weight Mn of 3000 to 30000, more preferably 5000 to 20000, particularly preferably 8000 to 18000, and most preferably 10,000 to 18000. When the number average molecular weight Mn is less than 3000, the cured product of the finally obtained resin composition is hard (hardness is high) or has a low elongation rate, so that a tendency to be inferior in impact resistance is seen. On the other hand, when the number average molecular weight Mn exceeds 30000, the viscosity of the polymer (A) as a reaction product increases, and consequently the viscosity of the resin composition increases, so that the workability is inferior.

  The molecular weight distribution (Mw / Mn) of the polyether polyol (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 viscosity of the polymer (A) as a reaction product increases, and as a result, the viscosity of the resin composition is high and the workability tends to be inferior.

  In the polyether polyol (a-1), the repeating unit of the oxyalkylene group constitutes the main skeleton (polyether part) of the polymer (A) molecular chain, and the OH group contained in the polyether polyol molecule is hydroxyl-reactive. It reacts with the functional group in the unsaturated carbonyl compound (a-2) to produce a polymer having an unsaturated carbonyl group at the molecular end.

(2) α, β unsaturated carbonyl compound having a functional group that reacts with a hydroxyl group (a-2)
The α, β unsaturated carbonyl compound (a-2) (hereinafter referred to as “hydroxyl-reactive unsaturated carbonyl compound” or “unsaturated carbonyl compound (a-2)”) having a functional group that reacts with a hydroxyl group is It is a compound represented by Formula (1).

  (1) In the formula, Q is a functional group that reacts with a hydroxyl group, or an atomic group that has a functional group that reacts with a hydroxyl group. As the functional group that reacts with the hydroxyl group, an isocyanate group or a carboxyl group is used. In addition, one or two unsaturated carbonyl groups may be included depending on the valence of the atom bonded to the carbonyl. Accordingly, the α, β unsaturated carbonyl compound (a-2) having a functional group that reacts with a hydroxyl group is specifically an unsaturated carboxylic acid represented by the following general formula (2) or the following general formula (3). Alternatively, an isocyanate group-containing unsaturated carbonyl compound represented by (3 ′) or a carboxyl group-containing unsaturated carbonyl compound represented by the following general formula (4) is applicable.

In the general formulas (1) to (4), R ¹ , R ² , and R ³ each represent hydrogen or a linear or branched alkyl group having 1 to 6 carbon atoms such as methyl, ethyl, or propyl. R ¹ and R ² may be the same or different. R ³ may be the same as or different from R ¹ and R ² .

  (3), (3 ′), (4) In the formula, X, X ′, and Y are intervening groups, and are linear or branched having 1 to 6 carbon atoms such as methylene, ethylene, propylene, trimethylene, and tetramethylene. An alkylene group, preferably methylene or ethylene. X and X 'may be the same or different, but are preferably the same.

  Accordingly, among the α, β unsaturated carbonyl compound (a-2), examples of the unsaturated carboxylic acid in which Q is a hydroxyl group include acrylic acid, methacrylic acid, crotonic acid, tiglic acid, angelic acid, and the like. Of these, acrylic acid and methacrylic acid are preferably used.

  Among the α, β unsaturated carbonyl compounds (a-2), the isocyanato group-containing unsaturated carbonyl compounds include 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 1,1-bis (acryloyl). And oxymethyl) ethyl isocyanate.

  Moreover, 2-acryloyloxyethyl succinic acid etc. can be used as a carboxyl group containing unsaturated carbonyl compound represented by General formula (4) among (alpha), (beta) unsaturated carbonyl compound (a-2).

As the unsaturated carbonyl compound having the above-described configuration, an acryloyl group or a methacryloyl group in which R ¹ is hydrogen or a methyl group and R ² is hydrogen in an α, β unsaturated carbonyl group is preferably used. Hereinafter, an acryloyl group or a methacryloyl group in which R ¹ is hydrogen or a methyl group and R ² is hydrogen (in the case where these are not particularly distinguished, they are collectively referred to as “(meth) acryloyl group”) will be described as a representative.

(3) Reaction of polyether polyol (a-1) and unsaturated carbonyl compound (a-2) The above-described polyether polyol (a-1) and hydroxyl-reactive unsaturated carbonyl compound (a-2) When reacted, the OH group in the polyether polyol (a-1) reacts with the isocyanate group or carboxyl group in the unsaturated carbonyl compound (a-2) to form a urethane bond or an ester bond. Therefore, the polymer (A) corresponds to a terminal-modified polyether in which the hydroxyl group in the polyether polyol (a-1) is esterified with an unsaturated carbonyl (that is, an unsaturated carbonyl-modified polyether), and an unsaturated carbonyl group. When is a (meth) acryloyl group, a (meth) acryloyl-modified polyether having a structure represented by the following general formula (5) is obtained.

  The polyether part in the above formula (5) is a polyether skeleton derived from the polyether polyol (a-1), that is, a part having a repeating unit of an oxyalkylene group, and the connecting part is a polyether polyol (a-1). ) And a hydroxyl group-reactive unsaturated carbonyl compound (a-2). When a polyol having 3 or more hydroxyl groups such as triol or tetraol is used as the polyether polyol (a-1), a combination of a linking part and a (meth) acryloyl group corresponding to the number of hydroxyl groups 3 or more.

Hereinafter, the polymer (A) obtained by the reaction of the polyether polyol (a-1) and the unsaturated carbonyl compound (a-2) will be referred to as a carbonyl-modified polyether, and as the unsaturated carbonyl compound (a-2), R ^The (meth) acryloyl-modified polyether (A) obtained when a (meth) acryloyl group-containing compound in which ¹ is hydrogen or a methyl group and R ² is hydrogen will be described as a representative.

  The production method of the (meth) acryloyl-modified polyether (A) is not particularly limited. Usually, in the presence of a catalyst, the polyether polyol (a-1) and the unsaturated carbonyl group is a (meth) acryloyl group. A carbonyl compound (a-2) (hereinafter referred to as “(meth) acryloyl compound (a-2)” when the (meth) acryloyl-modified polyether (A) is described as a representative) is heated to produce poly It can be obtained by urethanization or esterification of the hydroxyl group of the ether polyol.

  The mixing ratio of the polyether polyol (a-1) and the (meth) acryloyl compound (a-2) is such that the (meth) acryloyl compound (a) is equivalent to 1 equivalent of the hydroxyl group contained in the polyether polyol (a-1). -2) is preferably determined such that the functional group contained in the composition is 0.30 to 1.05 equivalents, and more preferably 0.40 to 1.05 equivalents. When the amount is less than 0.3 equivalents, the elongation of the cured product of the resulting resin composition tends to be small and the impact absorption tends to be inferior. When the amount exceeds 1.05 equivalents, the remaining (meth) acryloyl compound (a- The tendency of heat resistance and light resistance to decrease due to 2) is not preferable. Further, most of the (meth) acryloyl compound (a-2) used, specifically 90% or more, preferably 95% or more, more preferably 98% or more reacts to form a connecting part. Preferably it is.

  The amount of the polyether polyol (a-1) charged is such that the content of the oxyalkylene group as a polyether unit, preferably a repeating unit in the (meth) acryloyl-modified polyether (A) is 90% by mass or more. More preferably, it is 93% by mass or more, more 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.

  Examples of the catalyst used in the reaction 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 it is preferably 0.001 to 3% by mass with respect to the entire reaction mixture, 0.01 to 1 More preferably, it is mass%.

  The viscosity at 25 ° C. of the (meth) acryloyl-modified polyether (A) obtained as described above is usually 300 to 50000 mPa · s, preferably 300 to 30000 mPa · s, more preferably 300 to 20000 mPa · s. is there. Since a polymer having a viscosity at 25 ° C. of less than 50000 mPa · s can be used as the polymer as the main component of the composition, the workability of the resin composition can be satisfied.

  The molecular weight distribution (Mw / Mn) of the (meth) acryloyl-modified polyether (A) is preferably 1.8 or less, more preferably 1.6 or less, particularly preferably 1.4 or less, and 1.2 or less. Most preferred. If the molecular weight distribution (Mw / Mn) is large, the resulting resin composition tends to be high in viscosity and poor in workability.

  The content of the (A) (meth) acryloyl-modified polyether having the above configuration is 25 to 100% by mass with respect to the total content of the components (A), (C), and (D). The content is preferably 25 to 70% by mass, more preferably 30 to 60% by mass.

  The (meth) acryloyl-modified polyether (A) as described above is excellent in workability because of its low viscosity. Moreover, since the obtained hardened body is soft and has a large elongation, it is excellent in shock absorption and repairability. Furthermore, since the transparency is high and the properties relating to the stability of optical properties such as heat resistance, light resistance and moisture resistance are excellent, the excellent optical properties can be stably maintained.

  In this regard, when (meth) acryloyl-modified rubber is used, it is inferior to the case of using (meth) acryloyl-modified polyether (A) and has long optical properties such as light resistance and moisture resistance. Since it is inferior in durability, it is difficult to maintain excellent image quality over a long period of time. Further, since the elongation rate is insufficient, the repair property and the shock absorption property are not sufficient. In addition, a polymer (poly (meth) acryloyl-modified polyurethane) in which the molecular end of the polyurethane in which the structural unit consisting of a polyether part and a molecular block other than polyether are connected by a urethane bond is repeated with a (meth) acryloyl group In (meth) acryloyl-modified polyether (A), the viscosity is higher, so the workability is inferior, and the properties that affect the optical properties such as heat resistance, light resistance and moisture resistance are also (meth) It is inferior to acryloyl modified polyether (A). Poly (meth) acrylates having no polyether part also tend to have a high viscosity and are inferior in workability. Poly (meth) acrylate and (meth) acrylol-modified polyurethane with high viscosity can be reduced in viscosity by diluting with (meth) acrylate monomers, low-viscosity plasticizers, and solvents, but workability When a (meth) acrylate monomer in an amount necessary for securing is added, the curing shrinkage rate becomes too large, and the impact absorption and repair properties are inferior. Moreover, when a low-viscosity plasticizer is blended in a large amount, the plasticizer may leach out on the surface of the cured product.

[(B) Photopolymerization initiator]
The resin composition of the present invention contains (B) a photopolymerization initiator as an essential component. By containing a photopolymerization initiator, it can be quickly cured by light irradiation.

  (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-methylpropionyl) 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-diethylthioxa Thioxanthones such as 2-ton, 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 , 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 0.1-10 mass parts with respect to 100 mass parts of total content of (A), (C), and (D) component. Preferably it is. If it is 0.1 mass part or more, a resin composition can be hardened more fully, and odor generation and coloring of hardened | cured material can fully be suppressed by setting it as 10 mass parts or less. More preferably, it is 0.3-2 mass parts, More preferably, it is 0.3-1.5 mass parts. In addition, an ultraviolet cut layer may be provided on the protective plate from the viewpoint of protecting the display device. In this case, for example, it is necessary to perform curing at a wavelength of 380 nm or more. In such a case, acetophenones and / or oxy-phenyl-acetic acid 2- [2-oxo-2-ylate are contained with respect to 100 parts by mass of the total amount of components (A), (C), and (D). 1.0-5 parts by mass of phenyl-acetoxy-ethoxy] ethyl ester and / or oxy-phenyl-acetic acid 2- [2-hydroxy-ethoxy] ethyl ester and bis (2,4,6-trimethylbenzoyl) It is preferable to use 0.01 to 0.5 parts by mass of -phenylphosphine oxide and / or 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

[(C) Plasticizer]
The optical ultraviolet resin curable resin composition of the present invention may further contain (C) a plasticizer.
(C) As the plasticizer, conventionally known plasticizers such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, diisononyl phthalate, di-2-ethylhexyl phthalate, dibenzyl phthalate, diisodecyl phthalate, ditri phthalate Phthalates such as decyl phthalate and diundecyl phthalate; di-n-butyl adipate, diisobutyl adipate, dibutoxyethyl adipate, di-n-octyl adipate, diisooctyl adipate, diisononyl adipate, bis-2-ethylhexyl adipate, Adipic acid esters such as diisodecyl adipate; sebacic acid esters such as dibutyl sebacate, dioctyl sebacate, di-2-ethylhexyl sebacate Azelaic acid esters such as dihexyl azelate and dioctyl azelate; citric acid esters such as triethyl citrate, acetyl triethyl citrate and tri-n-butyl citrate; methyl phthalyl ethyl glycolate, ethyl phthalyl ethyl glyco Glycolic acid esters such as rate; Trioctyl trimellitate, Tri-n-octyl-n-decyl trimellitate, trimellitic acid esters such as trialkyl trimellitic acid (C4 to C11); Methylacetylricinoleate, Ricinoleic acid esters such as butylacetylricinoleate and glycerin monoricinoleate; maleic acid esters such as di-n-butylmalate; itaconic acid esters such as monobutyl itaconate; oleic acid esters such as butyl oleate; It can be used benzoic acid esters and the like; registration le phosphate, trioctyl phosphate, triphenyl phosphate, phosphoric acid esters such as trixylenyl phosphate.

  Further, not only the low-molecular plasticizer as described above, but also a polymer (or resin) having no (meth) acrylate group can be used as the plasticizer. Examples of the polymer plasticizer include polyether polyols listed as raw materials for acrylate-containing polyether polymers such as polyethylene glycol, polypropylene glycol, and ethylene oxide / propylene oxide copolymers; trade name “ADEKA” manufactured by ADEKA Carpol ”, polyether monools listed under the trade name“ New Pole ”manufactured by Sanyo Kasei Co., Ltd .; 50HB series mainly composed of propylene oxide and ethylene oxide; polyolefin resin such as polyethylene, polypropylene, polystyrene; (Meth) acrylic polymers that do not have polymerizable functional groups or double bonds in the side chains such as methyl methacrylate and polyacrylic acid; polyester resins such as polyethylene terephthalate; polyamides such as nylon 6,6 Fats; Rubber polymers such as polyisoprene, polybutadiene, polybutene; Thermoplastic elastomers; Petroleum resins such as C5 petroleum resins, C9 petroleum resins, C9 petroleum resins, C5 / C9 petroleum resins; Alicyclic saturated hydrocarbons Resins: Terpene resins such as terpene resins, terpene phenol resins, modified terpene resins, hydrogenated terpene resins; rosin resins such as rosin phenol; disproportionated rosin ester resins, polymerized rosin ester resins, hydrogenated (hydrogenated) ) Rosin ester resins such as rosin ester resins can be used. These can be used alone or in combination of two or more.

The (C) plasticizer is based on (A) (meth) acryloyl-modified polyether, (D) a molecular component having a molecular weight of 1000 or less, and the affinity, the viscosity of the composition, etc. Of these, polyether polyols and rhoene ester resins are preferable, and rosin ester resins are more preferably used.
By containing a rosin ester resin together with a (meth) acrylate compound having a molecular weight of 1000 or less, which will be described later, it tends to be able to absorb rapid chemical and physical changes such as excellent adhesion and heat shock resistance. .

The plasticizer preferably has a color tone (Hazen) of 200 or less, more preferably 150 or less, still more preferably 100 or less, most preferably so as not to affect the optical properties (particularly light transmittance) of the cured product. Preferably, 50 or less is selected.
The acid value (KOHmg / g) is preferably 30 or less, more preferably 20 or less, and still more preferably 10 or less.

  (C) The plasticizer is preferably blended in a proportion of 0 to 75 mass%, more preferably 10 to 75 mass%, based on the total content of the components (A), (C), and (D). More preferably, it is 20-60 mass%, Most preferably, it is 20-40 mass%. By increasing the blending ratio of the (C) plasticizer in the resin composition, the viscosity of the composition can be reduced, thereby improving the workability, as well as the flexibility, elongation, and impact absorption of the cured product. Can be increased. On the other hand, when the blending amount of (C) the plasticizer exceeds 75% by mass, the plasticizer tends to exude on the surface of the cured product, and adhesion to adherends such as display panels and protective plates. It causes a decrease and is not preferable.

  The (C) plasticizer is preferably used with (D) a polymerizable component having a molecular weight of 1000 or less, and particularly preferably used in combination with a (meth) acrylate compound having a molecular weight of 1000 or less. When used in combination with a (meth) acrylate compound, it is preferably blended in a proportion of 0 to 50% by weight, more preferably 10%, based on the total content of the components (A), (C), and (D). It is -40 mass%, More preferably, it is 15-35 mass%. In the presence of the component (D), if the content of the plasticizer (C) becomes too large, the content of the component (A) is relatively decreased, and as a result, heat resistance, light resistance, Various physical properties such as optical properties such as image forming properties, repair properties, and shock absorption tend to be lowered.

[(D) Polymerizable component having a molecular weight of 1000 or less]
In addition to the essential components (A) and (B) and the optional component (C) described above, the resin composition of the present invention can be used as a polymerizable component that can be co-cured with the essential component (A) as necessary. The following (meth) acrylate compound (D1) and one or more compounds (D2) containing a vinyl group other than the (meth) acryloyl group may be contained. From the viewpoint of adhesion, it is preferable to contain a (meth) acrylate compound, more preferably a monofunctional (meth) acrylate compound.

(D1) (meth) acrylate compound having a molecular weight of 1000 or less The (meth) acrylate compound having a molecular weight of 1000 or less is not particularly limited as long as it is a compound having a (meth) acryloyl group in the molecule. The following compounds are mentioned.
For example, as monofunctional (meth) acrylate, 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, undecyl (meth) acrylate Rate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, isomyristyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate Alkyl (meth) acrylates such as nonadecyl (meth) acrylate, eicodecyl (meth) acrylate, n-lauryl (meth) acrylate, stearyl (meth) acrylate;
Such as cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, 1-adamantyl (meth) acrylate, etc. Alicyclic (meth) acrylates;
Aromatic (meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate;
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, neopentyl glycol mono (meta ) Hydroxyl group-containing (meth) acrylates such as acrylates, and those obtained by adding cyclic ester compounds such as ε-caprolactone to these hydroxyl group-containing (meth) acrylic acid ester compounds;
Compounds obtained by addition reaction of glycidyl group-containing compounds such as alkyl glycidyl ether, allyl glycidyl ether, glycidyl (meth) acrylate and (meth) acrylic acid;
(2-Ethyl-2-methyl-1,3-dioxolan-4-yl) methyl (meth) acrylate, (2-isobutyl-2-methyl-1,3dioxolan-4-yl) methyl (meth) acrylate, cyclohexane Dioxolane-based (meth) acrylates such as spiro-2- (1,3-dioxolan-4-yl) (meth) acrylate;
Polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, (meth) acryloylmorpholine and the like;
Examples of the bifunctional (meth) acrylate include tricyclodecane dimethanol di (meth) acrylate, 1,6 hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, bisphenol A and (meth) acrylic acid. Etc. reacted with
Examples of the tri- or more functional (meth) acrylate include trimethylolpropane tri (meth) acrylate, glycerin tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa ( (Meth) acrylate, etc .;
Furthermore, various (meth) acrylates modified by adding ethylene oxide and / or propylene oxide to (meth) acrylate as described above; methoxy-polyethylene glycol (meth) acrylate, ethoxy-polyethylene glycol (meth) acrylate , Butoxy-polyethylene glycol (meth) acrylate, phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) acrylate, etc., and (meth) acrylate with ethylene glycol having one end alkoxylated or a polymer thereof; methoxy -Polypropylene glycol (meth) acrylate, ethoxy-polypropylene glycol (meth) acrylate, butoxy-polypropylene glycol (meth) acrylate , Phenoxy-dipropylene glycol (meth) acrylate, phenoxy-tripropylene glycol (meth) acrylate, etc., one end alkoxylated propylene glycol or a polymer thereof (meth) acrylate; dimethylaminoethyl (meth) acrylate, Amino group-containing (meth) acrylate such as diethylaminoethyl (meth) acrylate; (meth) acrylic acid, carboxyl group-containing (meth) acrylate such as 2- (meth) acryloyloxyethyl succinic acid; (meth) acrylic acid 2- Vinyloxyethyl, 3-vinyloxyethyl (meth) acrylate, 2-vinyloxypropyl (meth) acrylate, 1-methyl-2-vinyloxyethyl (meth) acrylate, 4-vinyloxybutyl (meth) acrylate, (meth) actyl 6-vinyloxyhexyl phosphate, 4-vinyloxycyclohexyl (meth) acrylate, 4-vinyloxymethylcyclohexylmethyl (meth) acrylate, 2- (2-vinyloxyethoxy) ethyl (meth) acrylate, (meth And vinyl group-containing (meth) acrylates such as 2- (2-vinyloxyisopropoxy) propyl acrylate and 2- {2- (2-vinyloxyethoxy) ethoxy} ethyl (meth) acrylate.
The above (meth) acrylate compounds can be used as one kind or a mixture of two or more kinds. Among them, a monofunctional (meth) acrylate having a Tg (glass transition temperature) of a homopolymer of −50 ° C. or higher is preferable, a monofunctional (meth) acrylate having a Tg of −30 ° C. or higher is more preferable, and a temperature of −20 ° C. or higher is preferable. Monofunctional (meth) acrylate is more preferable. By using a monofunctional (meth) acrylate having a glass transition temperature as described above, workability, curability and substrate adhesion can be improved by reducing the viscosity of the resin composition without reducing image unevenness. It becomes.

(D2) Vinyl group-containing compound other than (meth) acryloyl group having a molecular weight of 1000 or less
A vinyl group-containing compound other than a (meth) acryloyl group (hereinafter simply referred to as “vinyl group-containing compound”) (this means a vinyl group-containing compound other than a (meth) acryloyl group) is not particularly limited, Styrenes such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene; vinyl esters such as vinyl acetate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether; allyl alcohol, allyl glycidyl ether, ethylene glycol monoallyl ether Allyl compounds such as propylene glycol monoallyl ether; N-substituted maleimides such as N-phenylmaleimide, N-cyclohexylmaleimide and N-isopropylmaleimide; N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyl compounds such as N-vinyl-N-methylformamide, N-vinylimidazole, N-vinylacetamide; diallyl diphenate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl cyanurate, triallyl isocyanurate, etc. Allyl ester monomers; vinyl ether monomers such as triethylene glycol divinyl ether, cyclohexane dimethanol divinyl ether, hydroxybutyl vinyl ether, dodecyl vinyl ether; trimethylolpropane diallyl ether, pentaerythritol triallyl ether, allyl glycidyl ether, allyl ether of methylol melamine , Adipic acid ester of glyceryl diallyl ether, allyl acetal, methylol glyoxal urea And allyl ether monomers such as diethyl allate; maleate esters such as diethyl maleate and dibutyl maleate; and fumarate monomers such as dibutyl fumarate and dioctyl fumarate. It can be used as a mixture of two or more kinds, or may be used by mixing with a (meth) acrylate compound.

  The polymerizable component (D) having a molecular weight of 1000 or less (D1 component and / or D2 component) as described above is 0 to 40% by mass with respect to the total content of components (A), (C), and (D). It is preferable to mix | blend in the ratio, More preferably, it is 5-35 mass%, More preferably, it is 10-35 mass%. By using a (meth) acrylate compound and / or a vinyl group-containing compound, the viscosity and workability of the resulting resin composition can be adjusted, and excellent adhesion to the substrate can be imparted. Moreover, when it contains with (C) component, the content rate ((C + D) / of the total amount of component (C), (D) with respect to the total content of component (A), (C), and (D) (A + C + D)) is preferably 10 to 75% by mass, more preferably 20 to 60% by mass.

  Incidentally, (D) the addition of a polymerizable component having a molecular weight of 1000 or less tends to increase the curing shrinkage, but if the content of the component (D) is 40% by mass or less (preferably 30% by mass or less). The curing shrinkage rate can be suppressed to 3% or less. With this degree of curing shrinkage rate, the image forming performance and impact absorption of the display device are not affected.

[(E) Other components (additives)]
Furthermore, the optical ultraviolet curable resin composition of the present invention includes a thermosetting catalyst, an ultraviolet absorber, a light stabilizer, a chain transfer agent, a polymerization inhibitor, a leveling agent, an increase agent, as long as the effects of the present invention are not impaired. It may contain a viscosity agent, a viscosity reducer, a thixotropy imparting agent, a defoaming agent and the like.

The thermosetting catalyst is preferably added when it is necessary to cure a portion that is not exposed to light, and the combined use with a photopolymerization initiator is effective.
Specific examples of the thermosetting catalyst include benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, t-butyl peroxy-2-ethyl hexanoate, t-butyl peroxy octoate, and t-butyl peroxide. Organic peroxides such as oxybenzoate, cumene hydroperoxide, cyclohexanone peroxide, dicumyl peroxide, bis (4-t-butylcyclohexyl) peroxydicarbonate; azobisisobutyronitrile, 2-phenylazo-2, Examples include azo compounds such as 4-dimethyl-4-methoxyvaleronitrile, and these thermosetting catalysts may be used alone or in combination of two or more.

The thermosetting catalyst is preferably an organic peroxide, particularly preferably an organic peroxide having a 10-hour half-life temperature of 30 to 110 ° C, more preferably 40 to 100 ° C, still more preferably 50 to 90 ° C, Most preferred is an organic peroxide at 60 to 90 ° C.
It is preferable that the usage-amount of a thermosetting catalyst shall be 0.1-5 mass parts with respect to 100 mass parts of total content of (A), (C), and (D) component, More preferably, it is 0.3. -3 parts by mass, more preferably 0.5-2 parts by mass.

The chain transfer stabilizer is preferably used for adjusting the hardness of the cured product, improving adhesion to the substrate, and improving heat shock resistance. Specific examples of the chain transfer agent include β-mercaptopropionic acid, methyl-3-mercaptopropionate, 2-ethylhexyl-3-mercaptopropionate, n-octyl-3-mercaptopropionate, and methoxybutyl. -3-mercaptopropionate, stearyl-3-mercaptopropionate, 3,3'-thiodipropionic acid, dimethyl 3,3'-thiodipropionate, dithiodipropionic acid, laurylthiopropionic acid, thioglycol Monothiols such as acid, ammonium thioglycolate, monoethanolamine thioglycolate; trimethylolpropane tris (3-mercaptopropionate), tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, penta Erythritol tetrakis ( 3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), tetraethylene glycol bis (3-mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate), dipentaerythritol hexakis Polyfunctional thiols such as (3-mercaptopropionate) and diammonium dithioglycolate are exemplified, and polyfunctional thiols are preferred. These can be used alone or in combination.
The chain transfer stabilizer is preferably used in an amount of 0.1 to 5 parts by mass, more preferably 0.1 parts by mass with respect to 100 parts by mass of the total content of the components (A), (C), and (D). It is 3-3 mass parts, More preferably, it is 0.5-3 mass parts.

The light stabilizer is effective not only for improving light resistance but also for improving heat resistance. As the light stabilizer, a hindered amine light stabilizer is preferably used. Specific examples include TINUVIN 123, 144, 152, 292, 5100, 765 manufactured by BASF, and SANOL LS-770, 765, 292, 2626 manufactured by Sankyo Co., Ltd.
The amount of the light stabilizer used is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 100 parts by mass of the total content of the components (A), (C), and (D). -3 parts by mass, more preferably 0.5-5 parts by mass.

A commercially available ultraviolet absorber may be used. For example, salicylic acid esters such as benzotriazoles, benzoates, cyanoacrylates, benzophenones, hydroxyphenyltriazines, phenyl salicylate, pt-butylphenyl salicylate, p-octylphenyl salicylate; TINUVIN PS99-2,109,384-2,400,405,460,477DW, 470,900,928,1130,5236 (above, product name of BASF), Adekastab LA-52,57,62 (above, Asahi Denka ( Product name) etc. can be used.
It is preferable that the usage-amount of a ultraviolet absorber shall be 0.05-3 mass parts with respect to 100 mass parts of total content of (A), (C), and (D) component, More preferably, it is 0.1. ˜2 parts by mass, more preferably 0.1 to 1 part by mass.

  The additives (E) as described above may be used as a mixture, but the total content of additives is 100 parts by mass of the total content of components (A), (C), and (D). 0 to 30 parts by mass, more preferably 1 to 20 parts by mass, and particularly preferably 1 to 10 parts by mass.

[Preparation of UV-curable resin composition for optics]
The optical ultraviolet curable 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 300 to 15000 mPa · s, preferably 500 to 10000 mPa · s, more preferably 500 to 7000 mPa · s, particularly preferably 500 to 5000 mPa · s, and most preferably 500 to 3000 mPa · s. The resin composition of the present invention is a relatively low-viscosity composition as described above even if it is not blended as a main component of the polymer (A), that is, as a diluting compound such as a plasticizer or a polymerizable monomer. Can be obtained. Therefore, excellent workability such as easy filling and the shrinkage of the cured product by blending the low molecular weight compound for dilution can be kept low.

In addition, as described above, by blending a plasticizer or a polymerizable component having a molecular weight of 1000 or less as exemplified as the component (C) and the component (D), the viscosity can be reduced while suppressing the curing shrinkage rate. You can also plan.
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 optical ultraviolet curable resin composition of the present invention is preferably solvent-free. This is because the solvent for dilution needs to be volatilized after injection, and the residual solvent can cause a decrease in the photopolymerization speed, and can also 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 optical ultraviolet curable resin composition of the present invention having the above composition can be cured by ultraviolet irradiation. The curing reaction proceeds by vinyl polymerization of the (meth) acryloyl group in the (meth) acryloyl-modified polyether that is the component A by ultraviolet irradiation. When the component D (polymerizable component having a molecular weight of 1000 or less) is included, the compound of the component D is also involved and vinyl polymerization proceeds. In addition, hardening here means making it a state without fluidity | liquidity.

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 ratio of less than 3%, preferably 2.5% or less, more preferably 2% or less, still more preferably 1.5% or less, even more preferably 1.0% or less, most Preferably it can be 0.6% or less. By setting the curing shrinkage rate to less than 3%, it is possible to make the display device have no problem with image formation, and by setting it to 2.5% or less, it is possible to prevent a decrease in image formation. 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 70 or less, more preferably 50 or less, further preferably 30% or less, and most preferably 25 or less. When the C hardness is 70 or less, the impact absorbability 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 to 50% or more, the impact absorbability 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. Is preferred. 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 ultraviolet curable resin composition for optical use of the present invention from which the cured product as described above can be obtained is an electronic terminal such as a mobile phone, an electronic book, a touch panel device incorporating a liquid crystal display, a liquid crystal television, a plasma television, and no special glasses. In a display device such as a 3D liquid crystal television capable of stereoscopic display with a display panel and a protective plate, or between a display panel and a sheet-like functional member such as a touch panel, a switch liquid crystal, an electromagnetic wave shielding sheet, a polarizing plate It can be used as a filler and sticking agent for the space between the sheet-like functional members between the plate and the sheet-like functional members or in the case of a display device provided with a plurality of sheet-like functional members. That is, in the display device of the present invention, at least one of a display panel, a protective plate, and a sheet-like functional member, which is a constituent member, is bonded with a cured product of the optical ultraviolet curable resin composition of the present invention. It is. The display device of the present invention only has to include a display panel and a protective plate and / or a sheet-like functional member as constituent members. For example, the display panel and the protective plate are combined with the ultraviolet curable resin for optical use of the present invention. One or two or more layers of sheet-like functional members such as a touch panel, an electromagnetic wave shielding plate, and a polarizing plate are provided between the display panel and the protective plate, which are adhered with a cured product of the composition. A member bonded with a cured product of the optical ultraviolet curable resin composition of the present invention, and a sheet-like functional member such as a display panel and a switch liquid crystal are cured products of the optical ultraviolet curable resin composition of the present invention. Examples include pasted ones.

  Hereinafter, a representative example of a display device according to the present invention will be described with reference to the drawings. In addition, in the following figure, what has the same function uses the same code | symbol, and abbreviate | omits description.

  FIG. 1 is a schematic cross-sectional view of a liquid crystal display device in which a cured product 4 of the optical ultraviolet curable resin composition of the present invention is filled between a display panel 1 and a protective plate 2 (space 3). In the liquid crystal display device, the display panel 1 and the protective plate 2 are adhered (adhered) via the cured product 4 of the optical ultraviolet curable resin composition of the present invention, and are laminated and integrated. The protective plate 2 is made of a glass plate having the same size as the display panel 1, a plastic plate such as (meth) acrylic resin (for example, PMMA), polycarbonate resin (PC), or triacetyl cellulose (TAC), a sheet, or a film. Used. 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 polarizing plate (polarizing filter) has at least a laminated structure laminated in this order. Here, the polarizing plate (polarizing filter) is usually formed by sandwiching polyvinyl alcohol (PVA) dyed with iodine between two pieces of triacetyl cellulose (TAC), and the TAC surface is untreated and hard-coated. Processing, antireflection treatment, antistatic treatment, etc. are performed. The cured product 4 of the optical ultraviolet curable resin composition of the present invention has excellent adhesion to a glass plate, a plastic plate, and a polarizing plate (polarizing filter) in the outermost layer of the display panel 1. Have

  The display panel 1 only needs to have an image display function. In the case of a liquid crystal display device, the display panel 1 is a liquid crystal display panel, in the case of a plasma display device, it is a plasma panel, and in the case of an organic EL display device. Is an organic EL panel. These display panels 1 may be obtained by further attaching a polarizing film or an electromagnetic wave film to a display-side surface (protective plate-side surface) as desired. Further, the display side surface (the surface on the protective plate side) may have a touch panel function in which indium tin oxide or the like is deposited.

  The protective plate 2 may have black printing or the like on the outer peripheral portion of the back surface (the surface on the display panel side) such as the glass plate or plastic plate, and the surface has an antireflection layer, a hard coat layer, or the like. You may have. Further, the protective plate 2 may have a touch panel function in which a polarizing film or an electromagnetic wave film is attached to the surface on the display panel side as desired, or indium tin oxide or the like is vapor-deposited. There may be.

  FIG. 2 is a schematic cross-sectional view of a liquid crystal display device mounted with a touch panel using a cured product of the optical ultraviolet curable resin composition of the present invention. In the liquid crystal display device, a touch panel 5 is disposed on the display surface of the display panel 1 with a predetermined interval 6, a protective plate 2 is disposed with a predetermined interval, and a space between the display panel 1 and the touch panel 5. The display panel 1, the touch panel 5, and the protective plate 2 are stuck to each other by the cured products 4 and 4 ′ of the resin composition of the present invention filled in the space 6b between the touch panel 5 and the protective plate 2, and laminated. It is integrated. The touch panel 5 has a transparent conductive layer (indium tin oxide (ITO) vapor deposition layer) printed on one or both sides of a transparent plate such as a glass plate or a polyethylene terephthalate plate, and is pressed by an operator's finger or pen. When the transparent conductive layers come into contact with each other, the conductive state is established. Usually, in the case of single-sided printing, a transparent conductive layer having a two-layer structure of an X-axis ITO layer and a Y-axis ITO layer is printed. In the case of double-sided printing, the X-axis ITO layer and the Y-axis ITO layer are one side by one. It has a printed structure.

  In the embodiment of FIG. 2, a black print layer 8 is printed on the outer peripheral edge of the protective plate 2. As in 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, and a polarizing film or an electromagnetic wave film is attached. There may be. Similarly to the case of FIG. 1, the display panel 1 may be a display-side surface (protective plate-side surface) further bonded with a polarizing film or an electromagnetic wave film as desired.

  FIG. 3 is a schematic cross-sectional view of a display device in which two touch panels 5 and 5 ′ corresponding to the first and second sheet-like functional members are mounted and an electromagnetic wave shielding film 9 is provided on the display panel 1. It is. In this case, a space 6 a between the electromagnetic wave shielding film 9 and the first touch panel 5, a space 6 b between the first touch panel 5 and the second touch panel 5 ′, and a space between the second touch panel 5 ′ and the protective plate 2. 6c is filled with the ultraviolet curable resin composition for optics of the present invention, and the display panel 1, the touch panels 5, 5 ′, and the protective plate 2 are formed by the ultraviolet curable products 4, 4 ′, 4 ″ of the composition. They are attached to each other and integrated into a stack.

  Here, the first touch panel 5 and the second touch panel 5 ′ are usually ones with a transparent conductive layer (ITO layer) printed on one side, and the two touch panels 5 and 5 ′ are used as a set, and an X-axis ITO layer. And a Y-axis ITO layer. However, if desired, at least one of the first touch panel 5 and the second touch panel 5 ′ may have an ITO layer laminated on both sides.

  In the display device shown in FIG. 3, the electromagnetic wave shielding film 9 corresponds to a third sheet-like functional member, and may be attached to the display panel 1 via an adhesive sheet (not shown) or the like. You may affix using the hardened | cured material (not shown) of the resin composition of this invention. Moreover, in the display device provided with a plurality of touch panels, the electromagnetic wave shielding film 9 may not be provided.

FIG. 4 is a schematic cross-sectional view showing an example of a 3D liquid crystal display device adopting a parallax barrier method using a switch liquid crystal as a sheet-like functional member. The space 13 between the liquid crystal display panel 11 and the switch liquid crystal 12 is filled with the resin composition of the present invention, and the display liquid crystal panel 11 and the switch liquid crystal 12 are adhered by the cured product 4. In FIG. 4, 14 is a wiring board.
As in the case of the liquid crystal display panel 1, a polarizing film or an electromagnetic wave shielding film may be attached to the display liquid crystal panel 11 as desired.

  As described above, a display device in which a display panel, a protective plate, and a sheet-like functional member are bonded to each other using the cured product of the optical ultraviolet curable resin composition of the present invention, and laminated and integrated, is the present invention. Based on the characteristics of the resin composition, for example, the gap between the step and the unevenness due to the printed part and the wiring board is filled and cured, so that the display unevenness due to the gap, the unevenness and the step is extremely small. 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. Further, the optical ultraviolet curable resin composition of the present invention is excellent in adhesion to a display panel, a protective plate, and a sheet-like functional member, which are adherends, and also has excellent removability. It is useful at the manufacturing site of a display device that performs an operation of stacking and integrating a protective plate or a sheet-like functional member.

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.

<Synthesis of component A ((meth) acryloyl-modified polyether)>
Synthesis of A1:
The number average molecular weight Mn is 6000 (molecular weight distribution (Mw / Mn) = 1.06) as the polyether polyol (a-1) in a reactor equipped with a thermometer, a cooler, a gas introduction tube, and a stirrer. 300 g of polypropylene glycol (manufactured by Asahi Glass Co., Ltd., product number preminol 4006), 0.15 g of methoquinone, and 0.15 g of dibutyltin dilaurate were charged, and the mixture was heated to 70 ° C. while stirring. Then, 15.5 g of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko KK, product number Karenz MOI) as an isocyanate group-containing unsaturated carbonyl (a-2) (1.0 equivalent to the hydroxyl group in the polyether polyol) ) 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 methacryloyl-modified polyether having a urethane bond as the connecting portion was obtained. The isocyanate reaction rate determined by infrared spectroscopy was 98%. Moreover, the viscosity in 25 degreeC was 1050 mPa * s. Furthermore, the number average molecular weight (Mn) by GPC measurement was 6300, and molecular weight distribution (Mw / Mn) was 1.09.

Synthesis of A2-A9:
The polyether polyol (a-1) was changed to a polyether polyol having a number average molecular weight (Mn) and a molecular weight distribution as shown in Table 1, and as an isocyanate group-containing unsaturated carbonyl (a-2), 2- Except for changing the amount of methacryloyloxyethyl isocyanate (made by Showa Denko Co., product number Karenz MOI) or 2-acryloyloxyethyl isocyanate (made by Showa Denko Co., product number Karenz AOI) to the amounts shown in Table 1, it was the same as the synthesis of A1. Thus, (meth) acryloyl-modified polyether A2-A9 in which the connecting portion is a urethane bond was obtained. The isocyanate group reaction rate, number average molecular weight, and molecular weight distribution of the isocyanate group-containing unsaturated carbonyl compound are as shown in Table 1.

Synthesis of A10:
In a reactor equipped with a thermometer, a cooler, a gas introduction pipe, and a stirrer, the number average molecular weight Mn is 15000 (molecular weight distribution (Mw / Mn) = 1.09) as the polyether polyol (a-1). 300 g of polypropylene glycol (manufactured by Asahi Glass Co., Ltd., product number Preminol 4015), 0.15 g of methoquinone and 1.5 g of p-toluenesulfonic acid were charged, and the mixture was heated to 140 ° C. while stirring. Next, as the unsaturated carbonyl compound (a-2), 3.5 g of methacrylic acid (manufactured by Nippon Shokubai Co., Ltd.), which is one of unsaturated carboxylic acids whose reactive group with the hydroxyl group is a carboxyl group (in the polyether polyol) 1.0 equivalent to the hydroxyl group) was added dropwise over 2 hours. After completion of the dropping, the temperature was maintained at 150 ° C. for 3 hours to complete the reaction, and a methacryloyl-modified polyether having an ester bond at the connecting portion was obtained. The progress of the reaction was followed by the acid value of the reaction solution, and the final methacrylic acid reaction rate was 98%. Moreover, the viscosity in 25 degreeC was 9200 mPa * s. Further, by GPC measurement, the number average molecular weight (Mn) was 15500, and the molecular weight distribution (Mw / Mn) was 1.09.

Synthesis of A11:
Except for changing the unsaturated carboxylic acid to 2.9 g of acrylic acid (manufactured by Nippon Shokubai Co., Ltd.), an acryloyl-modified polyether A11 in which the connecting portion is an ester bond was obtained in the same manner as the synthesis of A10. The number average molecular weight, molecular weight distribution, and acrylic acid reaction rate of the acryloyl-modified polyether A11 are as shown in Table 1.

<Manufacture and evaluation of UV curable resin composition for optics>
The evaluation methods employed in this example are as follows.
〔Evaluation method〕
(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 (7-1) Heat resistance a
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 △: Slight discoloration ×: Large discoloration

(7-2) Heat resistance b
Measurement and evaluation were performed in the same manner as heat resistance a, except that the heating time in an oven at 100 ° C. was set to 1000 hours.

(8) Light resistance (8-1) Light resistance a
A test piece (width 50 mm × length 70 mm × thickness 1 mm) sandwiched between glass plates obtained by curing the obtained resin composition was measured with a metering weather meter (type “M6T”, manufactured by Suga Test Instruments Co., Ltd.). And irradiation intensity of 500 MJ / m ² using an irradiation intensity of 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 △: Slight discoloration ×: Large discoloration

(8-2) Light resistance b
Measurement and evaluation were performed in the same manner as light resistance a except that the light energy to be irradiated was changed to 700 MJ / m ² .

(9) Moisture resistance A sheet-like test piece (width 50 mm × length 70 mm × thickness 1 mm) obtained by curing the obtained resin composition is placed in a constant temperature and humidity machine (temperature 80 ° C., humidity 90% RH). ) For 100 hours, the turbidity of the sheet was visually confirmed and evaluated in the following three stages.
○: No turbidity △: Slightly turbid ×: Turbid

(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 ○: 60 seconds or more and less than 180 seconds △: 180 seconds or more and less than 500 seconds ×: 500 seconds or more

(11) Removability (repairability)
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 (SH-09B manufactured by Sharp) 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.
○: No image unevenness Δ: Very little image unevenness ×: Many image unevenness

(13) Shock Absorbability Prepare a test piece (width 50 mm × length 70 mm × thickness 0.3 mm) in a state sandwiched between glass plates obtained by curing the obtained resin composition, and 200 g steel on the test piece. The height at which the glass plate on the top surface was damaged when the sphere was dropped was determined and evaluated according to the following four levels. A glass plate having a thickness of 3 mm was used.
◎: 500 mm or more ○: 300 mm or more and less than 500 mm △: 200 mm or more and less than 300 mm ×: less than 200 mm

(14) Heat shock resistance The mobile phone obtained by measuring the image forming property is subjected to a heat shock test at three levels of 100 cycles, 300 cycles and 500 cycles, with -40 ° C for 30 minutes and 60 ° C for 30 minutes as one cycle. Then, the presence or absence of peeling or foaming at the interface between the liquid crystal module and the cured resin layer or the interface between the cured resin layer and the glass plate was confirmed and evaluated according to the following criteria.
A: No peeling or foaming after 500 cycles.
○: No peeling or foaming at 300 cycles. There is peeling or foaming in 500 cycles.
Δ: No peeling or foaming after 100 cycles. There is peeling or foaming in 300 cycles.
X: There is peeling or foaming in 100 cycles.

(15) Adhesion to substrate (N / cm)
Resin composition on a glass plate (width 25 mm × length 200 mm × thickness 1 mm) and triacetyl cellulose (TAC) plate (width 25 mm × length 200 mm × thickness 40 μm) having a silicone spacer having a thickness of 0.3 mm on four sides The resin composition was cured by filling the product, covering it with an easy-adhesion-treated PET film of the same size, and irradiating light from the PET film side with a high-pressure mercury lamp at 5 J / cm ² . After curing, the PET film is removed, left in an environment of 25 ° C. and 65% humidity for 24 hours, and the cured product is peeled off from the glass plate or TAC plate according to JIS K6848-2. The adhesion (N / cm) to (glass plate or TAC plate) was measured.

[Resin Composition No. Preparation of 1-9, production of cured product thereof, and evaluation: comparison of (meth) acryloyl-modified polyether with other polymers]
Resin composition No. 1-4:
100 parts of the (meth) acryloyl-modified polyether A1, A6, A10 or A11 synthesized above, photopolymerization initiator (manufactured by Ciba Specialty Chemicals, product number Irgacure 184D (corresponds to 1-hydroxy-cyclohexyl-phenyl-ketone)) 2 parts to prepare an optical ultraviolet curable resin composition (hereinafter referred to as “composition”) used for laminating and integrating the display panel and protective plate of the display device. Viscosity, workability (fillability), and image moldability were evaluated.
Next, the obtained composition was dropped onto 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. Thus, a sheet-like test piece was prepared. Based on the above-mentioned evaluation measurement method, the prepared test piece is cured shrinkage rate, hardness value, elongation rate, light transmittance, turbidity, heat resistance a, light resistance a, moisture resistance, removability (repair property), impact Absorbability was evaluated. The evaluation results are shown in Table 2.

Resin composition No. 5-9:
Instead of the component A, other polymers shown in Table 2, (meth) acrylic compounds, and plasticizers were blended in the amounts shown in Table 2, and resin composition No. 5-9 was prepared and evaluated based on the above evaluation method. The evaluation results are also shown in Table 2.
The other polymers shown in Table 2 are as follows.

(P1) Polyacrylate A reactor equipped with a thermometer, a condenser, a gas introduction tube, and a stirrer was charged with 100 g of butyl acrylate, 2-ethylhexyl acrylate, 100 g, 10 g of acrylic acid, and 500 parts of toluene as a solvent. The inside of the reactor was purged with nitrogen gas. Next, while stirring the above mixture, the temperature was raised to 85 ° C., and 1 part of 2,2′-azobismethylbutyronitrile as a polymerization initiator was dissolved in 300 g of toluene for 5 hours. Over the course of the 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. Subsequently, toluene was distilled off under reduced pressure to obtain a colorless transparent viscous liquid acrylic polymer. The viscosity at 25 ° C. of this acrylic polymer was 200700 mPa · s, the number average molecular weight Mn was 38000, and the molecular weight distribution (Mw / Mn) was 5.6.

(P2) Acryloyl-modified polyurethane Polypropylene having a number average molecular weight Mn of 3000 (molecular weight distribution (Mw / Mn) = 1.05) in a reactor equipped with a thermometer, a cooler, a gas introduction pipe, a dropping line and a stirrer 150 g of glycol (manufactured by Adeka, product number P-3000), 0.05 g of methoquinone and 0.05 g of dibutyltin dilaurate were added, and the temperature was raised to 70 ° C. After a fixed temperature, 17 g of hexamethylene diisocyanate was added dropwise over 1 hour, and after completion of the addition, the temperature was maintained at 70 ° C. 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 dropping, a temperature of 70 ° C. was maintained for 15 hours. The obtained polymer basically has a plurality of repeating units in which a polyether part derived from polypropylene glycol and hexamethylene derived from hexamethylene diisocyanate are linked by a urethane bond, and both ends of the polymer chain. Is an acryloyl group. The viscosity of such acryloyl-modified polyurethane at 25 ° C. was 405000 mPa · s, the number average molecular weight (Mn) was 10500, and the molecular weight distribution (Mw / Mn) was 4.6.

(P3) Mc modified rubber 1
It is a polyisoprene rubber having a methacryloyl group (trade name “Kuraprene UC203” manufactured by Kuraray Co., Ltd.).

(P4) Ac-modified rubber 2
This is a polybutadiene rubber having an acrylolyl group (trade name “BAC45” manufactured by Osaka Organic Chemical Co., Ltd.).

The D component ((meth) acrylate compound) shown in Table 2 is as follows.
HPMA: 2-hydroxypropyl methacrylate (Tg = 26 ° C.) (trade name “Light Ester HOP”, manufactured by Kyoeisha Chemical Co., Ltd.)
HDDA: 1,6-hexanediol diacrylate (Tg = 63 ° C.) (trade name “Light acrylate 1,6HD-A”, manufactured by Kyoeisha Chemical Co., Ltd.)
DPCM: dicyclopentenyloxyethyl methacrylate (Tg = 40 ° C.) (trade name “Fancryl FA-512M”, manufactured by Hitachi Chemical Co., Ltd.)
-BA: Butyl acrylate (Tg = -55 ° C)
2EHA: 2-ethylhexyl acrylate (Tg = −70 ° C.)

The C component (plasticizer) shown in Table 2 is as follows. In Table 2, the compounding amount of the plasticizer is the amount (part) shown in the numerical value in parentheses of the plasticizer name.
・ P1000: Polypropylene glycol (trade name “P-1000”, manufactured by Adeka)
DIDA: Diisodecyl adipate (Brand name “Vinizer 50”, manufactured by Kao Corporation)
-Terpene resin: Hydrogenated terpene resin (trade name “Clearon P85”, manufactured by Yasuhara Chemical Co., Ltd.)

  In Table 2, a composition No. using a (meth) acryloyl-modified polyether as the main polymer. 1-4 has a viscosity of about 1000 to 10000 mPa · s even if it is not diluted with any component D, satisfies workability, and has a low shrinkage of curing of 1.0% or less, and also satisfies image forming properties. did it. Furthermore, it has excellent optical properties such as heat resistance, light resistance, and moisture resistance, and can maintain excellent transparency over a long period of time.

  On the other hand, the composition no. No. 5 can reduce the viscosity by containing an acrylate compound having a molecular weight of 1000 or less, but the curing shrinkage rate is increased, the elongation rate is also reduced, and image forming properties, impact absorption properties, and repair properties are satisfied. I can't. Further, the transparency was slightly inferior, and the heat resistance and moisture resistance tended to be inferior.

  Composition No. using acryloyl-modified polyurethane In No. 6, even when a plasticizer was blended, the viscosity was high and workability could not be satisfied. Furthermore, the durability of optical properties such as heat resistance a, light resistance a, and moisture resistance was inferior.

  When (meth) acryloyl-modified rubber was used (Composition No. 7-9), the cure shrinkage ratio was large and the image forming property was inferior. Further, the elongation rate tends to be inferior, and the impact absorbability tends to be inferior. It is possible to improve the elongation rate by adding a plasticizer (Composition Nos. 8 and 9), but since the viscosity tends to increase due to the addition of the plasticizer, workability tends to be inferior. It was in. Also, the durability of optical properties such as light resistance and moisture resistance tended to be inferior.

[Resin Composition No. Preparation and Evaluation of 11-17: Kinds and Physical Properties of (Meth) acryloyl Modified Polyether]
Except for using the (meth) acryloyl-modified polyether shown in Table 3 as the component A, No. 1 was used. In the same manner as in No. 1, a resin composition was prepared, and further a sheet-like test piece was prepared and evaluated based on the above evaluation method. The evaluation results are also shown in Table 3. For reference, the resin composition No. The results of 1-4 are also shown.

  Table 3 shows a composition using (meth) acryloyl-modified polyether as the main polymer. Although there were differences in workability and impact absorbability, all of them were excellent in properties relating to durability of optical properties such as heat resistance, light resistance, and moisture resistance. Composition Nos. 3 and 4 and Composition No. 14 and 15 are compositions in which the former is a (meth) acryloyl-modified polyether having an ester bond as a linking part, and the latter is a (meth) acryloyl-modified polyether having a urethane bond as a linking part. Since the molecular weight and viscosity of the film were the same, the evaluation results were also the same. Therefore, it can be seen that the influence of the type of the connecting portion on the optical characteristics, impact absorbability, image formability, and repairability is small.

  Regarding workability, the smaller the molecular weight of the (meth) acryloyl-modified polyether that is the component A, the lower the viscosity, and the lower the viscosity of the prepared composition. On the contrary, with respect to impact absorption, the composition having a higher viscosity tends to be superior, and when the viscosity is low, the composition No. High impact absorption can be obtained only when the elongation percentage is increased as in FIG.

[Resin Composition No. Preparation and Evaluation of 21-27: Effect of Addition of Plasticizer]
The amount of (meth) acryloyl-modified polyether (component A) and plasticizer (component C) shown in Table 4 in the amount shown in Table 4 and the photopolymerization initiator B component (manufactured by Ciba Specialty Chemicals, product number Irgacure 184D) ) 2 parts were mixed and composition No. In the same manner as in No. 1, a resin composition was prepared, and further a sheet-like test piece was prepared and evaluated based on the above evaluation method. The results are also shown in Table 4. For reference, a resin composition No. containing neither a plasticizer nor a (meth) acrylate compound is used. The evaluation results of 2 to 4 and 12 to 14 are also shown.
In Table 4, “P400” is polypropylene glycol (trade name “P-400”, manufactured by Adeka).

  Composition No. 21-27 is a case where polypropylene glycol is blended as a plasticizer. Workability can be improved by lowering the viscosity of the composition by blending a plasticizer. Further, since the elongation rate tends to increase due to the blending of the polypropylene glycol plasticizer, the impact absorbability tends to be improved. On the other hand, the properties relating to the durability of optical properties such as heat resistance, light resistance and moisture resistance were not lowered by the blending of the plasticizer.

[Resin Composition No. Preparation and Evaluation of 31-38: (D) Effect of Addition of Polymerizable Component with Molecular Weight of 1000 or Less]
50 parts of (meth) acryloyl-modified polymer A7 as component (A), photopolymerization initiator as component (B) (Ciba Specialty Chemicals, product number Irgacure 184D (corresponds to 1-hydroxy-cyclohexyl-phenyl-ketone)) 2 Parts, (C) 20 parts of rosin ester (“KE-311” of Arakawa Chemical Industries, Hazen value 40, acid value 6.5, softening point (ring and ball method) 95 ° C.) as a plasticizer, and (D) As a polymerizable component having a molecular weight of 1000 or less, the (meth) acrylate compound shown in Table 5 and (E) other additives are mixed in the amounts shown in Table 5, and the same as in No. 1, the resin composition The composition was evaluated for viscosity, workability (fillability), image moldability, and adhesion to the substrate.
Next, no. A sheet-like test piece was prepared in the same manner as in No. 1, and based on the above-described evaluation measurement method, curing shrinkage rate, hardness value, elongation rate, light transmittance, turbidity, heat resistance b, light resistance b, moisture resistance, re-peeling (Repairability), shock absorption, and heat shock resistance were evaluated. The evaluation results are shown in Table 5. For reference, a composition No. consisting of 100 parts of (meth) acryloyl-modified polymer A7 and 2 parts of a photopolymerization initiator (Irgacure 184D) was used. 15 results are also shown.

In addition, (D) component and (E) component which are shown in Table 5 are as follows.
IB-A: Isobornyl acrylate (Tg = 94 ° C.) (manufactured by Nippon Shokubai)
DPA: dicyclopentanyl acrylate (Tg = 120 ° C.) (Hitachi Chemical Industries FA-513A)
EC-A: ethoxydiethylene glycol acrylate (Tg = −70 ° C.) (Kyoeisha Chemical)
DPCA: dicyclopentenyloxyethyl acrylate (Tg = 10-15 ° C.) (Hankuri FA-512-A from Hitachi Chemical)
MEDOL-10: (2-Methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate (Tg = -7 ° C.) (Osaka Organic Chemical Industry)
4-HBA: 4-hydroxybutyl acrylate (Tg: -32 ° C) (Osaka Organic Chemical Industry)

TINUVIN765: hindered amine light stabilizer PEMP: pentaerythritol tetrakis (3-mercaptopropionate)
PE-1: Pentaerythritol tetrakis (3-mercaptobutyrate) (manufactured by Showa Denko)

As can be seen from Table 5, the addition of (C) a plasticizer and (D) a (meth) acrylate compound having a molecular weight of 1000 or less can reduce the viscosity of the composition and improve workability.
No. 31-38 and No. From the comparison with 15, even if the hardness is comparable, the elongation can be improved by adding the components (C), (D) and (E), and the adhesion and heat shock resistance are also improved. I understand that.

  No. 31 and no. Comparison with 36-38 shows that the hardness, elongation, and adhesion of the cured product are affected by the type of additive. When the polyfunctional thiol is not included at all (No. 37), the cured product becomes stiffer and the adhesion and elongation are lower than when the polyfunctional thiol is contained (No. 31, 36, 38). There was a tendency to decrease. No. 36 and 38 tended to be inferior in high heat resistance b and light resistance b. Furthermore, no. Comparison of 35, 37, and 38 shows that the combined use of a specific polyfunctional thiol and a light stabilizer is effective for ensuring high heat resistance b, light resistance b, high elongation, and low hardness.

  The cure shrinkage ratio was increased by the addition of rosin ester plasticizer, (meth) acrylate compound, and additives (light stabilizer, chain transfer agent), but all were less than 3%, preferably It can be seen that it was 2.5% or less, and it did not cause a decrease in image formability.

[Resin Composition No. Preparation and Evaluation of 41-46: (D) Effect of Addition of Plasticizer in the Presence of Component (D)]
As shown in Table 6, (A) component, (C) component, (D) component, and (E) component are mix | blended, Furthermore, photopolymerization initiator (Ciba Specialty Chemicals company make, Irgacure 184D) 2 parts And No. In the same manner as in No. 1, a resin composition was prepared, and the viscosity, workability (fillability), image moldability, and adhesion to the substrate of the composition were evaluated. Furthermore, a sheet-like test piece was prepared, and based on the above evaluation measurement method, the curing shrinkage rate, hardness value, elongation rate, light transmittance, turbidity, heat resistance b, light resistance b, moisture resistance, removability ( Repairability), shock absorption, and heat shock resistance were evaluated. The evaluation results are shown in Table 6. For reference, the composition No. The results of 31 are also shown.

  “Liquid rubber” in Table 6 is polybutene (trade name “VL-100”, manufactured by JX Nippon Oil & Energy Corporation).

  No. Nos. 31, 42, 43 and 46 are cases where rosin ester is used as a plasticizer. 41, 44, and 45 are the cases where other plasticizers are used. From these comparisons, it is understood that in the presence of the (meth) acrylate compound as the component (D), the use of rosin ester as the plasticizer is superior in adhesion. Moreover, if addition of (C) component and (D) component is 75 weight% or less with respect to the total content of (A), (C), and (D) component, a cure shrinkage rate will be less than 3% It can be seen that the elongation and adhesion can be improved while suppressing to (preferably 2.5% or less).

  Since the optical ultraviolet curable resin composition of the present invention is a low-viscosity liquid, it can be applied to display devices of various sizes and has excellent versatility and excellent workability. Furthermore, the cured product can maintain excellent optical characteristics against environmental changes such as light, heat, and moisture, and has a good balance of properties such as removability, impact absorption, and adhesion. Since it can exhibit simultaneously, it is suitable as an ultraviolet curable resin composition used for sticking between a display panel, a protective plate, and a sheet-like functional member, which are constituent members of various display devices.

DESCRIPTION OF SYMBOLS 1,11 Display panel 2 Protection board 4,4 ', 4 "Hardened | cured material of the ultraviolet curable resin composition for optics 5,5' Touch panel 9 Electromagnetic wave shielding film 12 Switch liquid crystal

Claims (18)

An ultraviolet curable resin composition used for adhering at least two selected from the group consisting of a display panel, a protective plate, and a sheet-like functional member used in a display device, UV curable resin composition
(A) It has an acryloyl group or a methacryloyl group and has a molecular weight obtained by a reaction between a polyether polyol (a-1) and an α, β unsaturated carbonyl compound (a-2) having a functional group that reacts with a hydroxyl group. An optical ultraviolet curable resin composition comprising a polymer having a distribution (Mw / Mn) of 1.2 or less and (B) a photopolymerization initiator. The ultraviolet curable resin composition for optics according to claim 1, wherein the functional group is an isocyanate group or a carboxyl group. The optical ultraviolet curable resin composition according to claim 1 or 2, wherein a molecular weight distribution (Mw / Mn) of the polyether polyol (a-1) is 1.1 or less . The optical ultraviolet curable resin composition according to any one of claims 1 to 3, wherein the α, β unsaturated carbonyl compound (a-2) is 2-acryloyloxyethyl isocyanate or 2-methacryloyloxyethyl isocyanate. object. The optical ultraviolet curable resin composition according to claim 1, wherein the α, β unsaturated carbonyl compound (a-2) is acrylic acid or methacrylic acid. The optical polyol curable resin composition according to claim 1, wherein the polyether polyol (a-1) has a number average molecular weight of 3000 or more. The said ultraviolet-curable resin composition for optics in any one of Claims 1-6 in which the said polyether polyol (a-1) contains polypropylene glycol. Furthermore, (C) The plasticizer is included, The ultraviolet curable resin composition for optics in any one of Claims 1-7 characterized by the above-mentioned. The optical ultraviolet curable resin composition according to claim 8, wherein the (C) plasticizer is a rosin ester resin. The optical ultraviolet curable resin composition according to claim 8, wherein the (C) plasticizer is a polyether polyol. Furthermore, (D) The ultraviolet curable resin composition for optics in any one of Claims 1-10 containing the polymeric component of 1000 or less molecular weight. The optical ultraviolet curable resin composition according to claim 11, wherein the polymerizable component (D) having a molecular weight of 1000 or less is a (meth) acrylate compound. The optical ultraviolet curable resin composition according to claim 12, wherein the polymerizable component (D) having a molecular weight of 1000 or less is a monofunctional (meth) acrylate compound having a glass transition temperature of -50 ° C or higher. (C) A plasticizer and (D) a polymerizable component having a molecular weight of 1000 or less are contained, and the total content of (C) the plasticizer and (D) the polymerizable component is the component (A), the component (C), and (D) It is 75 mass% or less of content total amount of a component, The ultraviolet curable resin composition for optics in any one of Claims 1-13. The ultraviolet curable resin composition for optics according to any one of claims 1 to 14, wherein the viscosity at 25 ° C is 300 to 15000 mPa · s. Hardened | cured material obtained by hardening | curing the ultraviolet curable resin composition for optics in any one of Claims 1-15 by ultraviolet irradiation. In a display device comprising a display panel and a protective plate and / or a sheet-like functional member, at least a combination of the display panel and a protective plate or a sheet-like functional member, or a combination of the protective plate and a sheet-like functional member Any one set is stuck with the hardened | cured material of Claim 16, The display apparatus characterized by the above-mentioned. The display device includes a plurality of sheet-like functional members, and at least the first sheet-like functional member and the second sheet-like functional member are attached with the cured product according to claim 16. Item 18. A display device according to Item 17.

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