JP2014221893A - Adhesive for display panel, display panel using the same and method for producing display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive for a display panel which does not flow out from a member adhered by an adhesive for a display panel, and to provide a display panel using the adhesive for a display panel and a method for producing a display panel using the adhesive for a display panel.SOLUTION: There is provided an adhesive for a display panel which comprises: (A) a polymer containing 1.5 or more polymerizable carbon-carbon double bonds on average in the molecule and having a number average molecular weight (Mn) of 5000 or more; (B) a polymer containing one or less polymerizable carbon-carbon double bond on average in the molecule and having a number average molecular weight (Mn) of 5000 or more; (C) a photopolymerization initiator; and (D) hydrophilic silica having a specific surface area of 200 m/g or more, wherein the amount of (D) component is 4 pts.wt. or more and 20 pts.wt. or less based on the total 100 pts.wt. of (A) component and (B) component and the maximum coarse particle diameter is 30 μm or less.

Description

(A) Polymer having an average of 1.5 or more polymerizable carbon-carbon double bonds in the molecule and a number average molecular weight (Mn) of 5,000 or more, (B) Polymerizable in the molecule A polymer having an average of 1 or less carbon-carbon double bonds and having a number average molecular weight (Mn) of 5,000 or more, (C) a photopolymerization initiator, and (D) a specific surface area of 200 m ² / g or more. (D) component is 4 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight as a total of the components (A) and (B). The present invention relates to a display panel adhesive having a maximum coarse particle of 30 μm or less, a display panel, and a method for manufacturing a display panel.

  In recent years, a plurality of optical members have been used for display panels of image display devices such as mobile phones, tablet PCs, and personal computers. For example, when the touch panel is a member different from the liquid crystal display module, the touch panel is disposed on a display module such as a liquid crystal display module or an organic EL module, and a transparent cover material is further provided on the touch panel. Has been placed. When the touch panel function is incorporated in the liquid crystal display module, a transparent cover material is disposed on the liquid crystal module.

  In order to reduce reflected light between these display modules and the touch panel, between the touch panel and the transparent cover material, and between the liquid crystal module and the transparent cover material, it has a photopolymerizable functional group having a refractive index close to that of the optical member. Adhesives for display panels that are curable with energy rays (UV) using urethane acrylate and / or epoxy acrylate as a binder polymer are increasingly used.

  As a method of using the display panel adhesive, the distance between the coated body to which the display panel adhesive is applied and the bonded body is narrowed, and the display panel adhesive is spread between the coated body and the bonded body. After that, a method of curing the display panel adhesive with energy rays (UV) and fixing the coated body and the bonded body is exemplified. However, when the adhesive for display panel is spread between the object to be bonded and the object to be bonded, the adhesive for display panel is not applied until the adhesive for display panel is cured by irradiating energy rays (UV). Or it protruded from the to-be-bonded body, and the periphery might be contaminated.

  On the other hand, a liquid stopper (dam) may be formed outside the application region before the display panel adhesive is applied in order to prevent the display panel adhesive from sticking out of the object to be applied or the object to be bonded. It has been proposed (Patent Documents 1 and 2). However, in order to prevent air from entering the display part, it is necessary for the display panel adhesive to get over the liquid stop part. It sometimes protrudes from the paste and contaminates the surrounding area.

  As a method of curing the display panel adhesive that is about to protrude from the coated body or the bonded body, the display panel adhesive is cured by irradiating energy rays (UV) from the side surface of the coated body and the bonded body. Have been proposed (Patent Documents 3 and 4). However, it is difficult to uniformly irradiate the side surface of the coated body and the bonded body with energy rays (UV), and since the fluidity of the adhesive for display panels is high, display is performed by irradiating energy rays (UV). Before the panel adhesive is cured, the display panel adhesive sometimes protrudes from the coated body or the bonded body.

  On the other hand, an adhesive for display panels containing a polymer having a polymerizable carbon-carbon double bond in the molecule and a photopolymerization initiator has been proposed (Patent Document 5). In order to spread the adhesive for display panel between the object to be bonded and the object to be bonded by narrowing the distance to the object to be bonded, the viscosity of the adhesive for display panel is set low, and the adhesive for display panel It is necessary to make it spread easily when the distance to the object to be bonded is narrowed. However, on the contrary, since the fluidity of the adhesive for display panel is high, the adhesive for display panel may flow out from the end of the bonded body of the coated body and the bonded body, and may contaminate the surrounding area. There was a need for improvement.

  On the other hand, an adhesive for a display panel containing a polymer having a polymerizable carbon-carbon double bond and a photopolymerization initiator has been proposed (Patent Document 5). However, there is no description about adding specific hydrophilic silica.

JP 2009-8851 A JP 2010-66711 A JP 2009-186955 A JP 2009-86656 A JP 2012-41499 A

  An object of the present invention is to provide an adhesive for a display panel in which the adhesive does not protrude from a member to be bonded with an adhesive, a display panel using the adhesive, and a method for manufacturing a display panel using the adhesive. In particular, after narrowing the distance between the coated body to which the adhesive is applied and the bonded body, spreading the adhesive between the coated body and the bonded body, the adhesive is cured with energy rays, and the coated body. In the manufacturing method of the display panel that fixes the object to be bonded, the adhesive for the display panel in which the adhesive does not protrude from the object to be bonded and the object to be bonded, before the adhesive is cured with energy rays, is used. An object of the present invention is to provide a display panel and a method for manufacturing a display panel using an adhesive in the previous period.

As a result of intensive studies by the present inventors in view of the above-described present situation, the specific surface area is 200 m ² / g or more, and 4 parts by weight or more with respect to 100 parts by weight in total of the components (A) and (B), 20 The present inventors have found that the above-mentioned problems can be solved by using an adhesive for display panels containing hydrophilic silica in an amount of not more than parts by weight and having a maximum coarse particle of not more than 30 μm, thereby completing the present invention.
That is,
(A) a polymer containing 1.5 or more polymerizable carbon-carbon double bonds on average in the molecule and having a number average molecular weight (Mn) of 5,000 or more,
(B) a polymer containing an average of 1 or more polymerizable carbon-carbon double bonds in the molecule and having a number average molecular weight (Mn) of 5,000 or more,
(C) a photopolymerization initiator, and (D) hydrophilic silica having a specific surface area of 200 m ² / g or more,
It is an adhesive for display panels including
The component (D) is 4 parts by weight or more and 20 parts by weight or less with respect to a total of 100 parts by weight of the component (A) and the component (B),
The present invention relates to an adhesive for a display panel having a maximum coarse particle of 30 μm or less.

  The component (A) and / or the component (B) is preferably a (meth) acrylic polymer.

  The amount of component (C) is preferably 0.001 to 10 parts by weight, with the total weight of component (A) and component (B) being 100 parts by weight.

  The present invention relates to a display panel using the display panel adhesive.

  A method of manufacturing a display panel in which an object to be applied to which the adhesive for display panel is applied and an object to be bonded to which the object is bonded are bonded to each other with an adhesive for display panel, and the object to which the adhesive for display panel is applied And the display panel adhesive is spread between the coated body and the bonded body, the display panel adhesive is cured with energy rays, and the coated body and the bonded body The present invention relates to a method for manufacturing a display panel for fixing a display panel.

  According to the present invention, an adhesive for a display panel in which an adhesive does not protrude from a member to be bonded with an adhesive, a display panel using the adhesive, and a method for manufacturing a display panel using the adhesive are provided. Can do. In particular, after narrowing the distance between the coated body to which the adhesive is applied and the bonded body, spreading the adhesive between the coated body and the bonded body, the adhesive is cured with energy rays, and the coated body. In the manufacturing method of the display panel that fixes the object to be bonded, the adhesive for the display panel in which the adhesive does not protrude from the object to be bonded and the object to be bonded, before the adhesive is cured with energy rays, is used. Display panel and a method for manufacturing a display panel using an adhesive in the previous period can be provided.

It is a figure of the bonding method of a display panel.

  Hereinafter, the adhesive for display panels of the present invention will be described in detail.

The present invention includes (A) a polymer having an average of 1.5 or more polymerizable carbon-carbon double bonds in the molecule and a number average molecular weight (Mn) of 5,000 or more,
(B) a polymer containing an average of 1 or more polymerizable carbon-carbon double bonds in the molecule and having a number average molecular weight (Mn) of 5,000 or more,
(C) a photopolymerization initiator,
(D) hydrophilic silica having a specific surface area of 200 m 2 / g or more,
It is an adhesive for display panels including
The (D) component is an adhesive for a display panel having 4 to 20 parts by weight with respect to a total of 100 parts by weight of the (A) and (B) components, and a maximum coarse particle of 30 μm or less. .

<< (A) component and (B) component >>
The component (A) is a polymer containing 1.5 or more polymerizable carbon-carbon double bonds on average in the molecule and having a number average molecular weight (Mn) of 5,000 or more, and the component (B) Is a polymer having an average of one or more polymerizable carbon-carbon double bonds in the molecule and a number average molecular weight (Mn) of 5,000 or more.
The skeletons of the component (A) and the component (B) may be the same or different, but are preferably the same skeleton from the viewpoint of compatibility.

  The polymer is preferably polysiloxane, polyether, or vinyl polymer.

  As the polysiloxane, alkyl polysiloxane is preferable.

  The polyether is preferably an oxyalkylene polymer, and more preferably polyoxyethylene or polyoxypropylene.

  Examples of the vinyl polymer include hydrocarbon polymers such as polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene, (meth) acrylic monomers, acrylonitrile monomers, aromatic vinyl monomers, and fluorine-containing vinyls. A polymer produced mainly by polymerizing a monomer selected from the group consisting of a system monomer and a silicon-containing vinyl monomer is preferred. Here, “mainly” means that 50 mol% or more of the monomer units constituting the vinyl polymer is the above monomer, and preferably 70 mol% or more. Furthermore, as the vinyl polymer, a (meth) acrylic polymer produced by mainly polymerizing polyisobutylene and a (meth) acrylic monomer is preferable, and a (meth) acrylic polymer is more preferable. As the (meth) acrylic polymer, an acrylic polymer is preferable, and an acrylate polymer is more preferable.

  Among the preferable polymers, a (meth) acrylic polymer produced by mainly polymerizing a (meth) acrylic monomer is most preferable.

  The molecular weight and molecular weight distribution of the polymer of component (A) and component (B) are measured by gel permeation chromatography (GPC). In the GPC measurement in the present invention, chloroform is used as the mobile phase, the measurement is performed with a polystyrene gel column, and the molecular weight can be determined in terms of polystyrene.

  The number average molecular weight of the component (A) and the component (B) is 5,000 or more, preferably 5,000 to 300,000, and more preferably 5,000 to 100,000.

  The molecular weight distribution is not particularly limited, but is preferably less than 1.8, more preferably 1.7 or less, even more preferably 1.6 or less, even more preferably 1.5 or less, and particularly preferably Is 1.4 or less, and most preferably 1.3 or less. When the molecular weight distribution is 1.8 or more, the viscosity increases and the handling tends to be difficult.

  The ratio of the component (A) to the component (B) in the present invention is preferably 5:95 to 95: 5, and more preferably 20:80 to 80:20.

  As a method for producing the polymer of the component (A) and the component (B), a known method can be used, and an example is described below.

<Polysiloxane>
Known methods for producing organopolysiloxanes by hydrolyzing organochlorosilane, Japanese Patent No. 2599517, Japanese Patent Laid-Open No. 56-151731, Japanese Patent Laid-Open No. 59-66422, Japanese Patent Laid-Open No. 59-68377 Can be obtained by a known method such as a hydrolysis method in the presence of a basic catalyst or an acid catalyst. Examples of the terminal functional group of the polymer include an alkoxysilyl group, a silanol group, and a hydroxyl group.

<Polyether>
The method for synthesizing the polyether (oxyalkylene polymer) is not particularly limited. For example, it can be obtained by ring-opening polymerization of a monoepoxide in the presence of an initiator and a catalyst.

  Specific examples of the initiator include ethylene glycol, propylene glycol, butanediol, hexamethylene glycol, methallyl alcohol, bisphenol A, hydrogenated bisphenol A, neopentyl glycol, polybutadiene diol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene Examples thereof include dihydric alcohols such as glycol, polypropylene triol, polypropylene tetraol, dipropylene glycol, glycerin, trimethylol methane, trimethylol propane, and pentaerythritol, polyhydric alcohols, and various oligomers having a hydroxyl group.

  Specific examples of the monoepoxide include ethylene oxide, propylene oxide, α-butylene oxide, β-butylene oxide, hexene oxide, cyclohexene oxide, styrene oxide, α-methylstyrene oxide, and other alkylene oxides, methyl glycidyl ether, ethyl Examples thereof include alkyl glycidyl ethers such as glycidyl ether, isopropyl glycidyl ether, and butyl glycidyl ether, allyl glycidyl ethers, and aryl glycidyl ethers.

  As the catalyst and polymerization method, for example, a polymerization method using an alkali catalyst such as KOH, for example, a transition metal compound such as a complex obtained by reacting an organoaluminum compound and porphyrin disclosed in JP-A-61-215623 Polymerization using a porphyrin complex catalyst, for example, a polymerization method using a double metal cyanide complex catalyst, a polymerization method using a cesium catalyst, a polymerization method using a phosphazene catalyst, and the like disclosed in Japanese Patent Publication Nos. 46-27250 and 59-15336. However, it is not particularly limited. Among these, a polymerization method using a double metal cyanide complex catalyst is preferable from the viewpoint of easily obtaining a polymer having a high molecular weight and little coloring.

In addition, the main chain skeleton of the oxyalkylene polymer is a hydroxyl group-terminated oxyalkylene polymer in the presence of a basic compound such as KOH, NaOH, KOCH ₃ , NaOCH ₃ or the like, and a bifunctional or higher alkyl halide such as CH can also be obtained by chain extension due ₂ Cl _{2, CH 2} Br ₂ or the like.

  Further, the main chain skeleton of the oxyalkylene polymer may contain other components such as a urethane bond component as long as the characteristics of the oxyalkylene polymer are not significantly impaired.

<Vinyl polymer>
(Hydrocarbon polymer)
The hydrocarbon polymer is a polymer that does not substantially contain a carbon-carbon unsaturated bond other than an aromatic ring. For example, 1,2-polybutadiene, 1,4-polybutadiene, polyethylene, polypropylene, polyisobutylene , Hydrogenated polybutadiene, hydrogenated polyisoprene, and the like.

  The polymer constituting the main chain skeleton of the hydrocarbon polymer used in the present invention is (1) carbon number 1 such as ethylene, propylene, 1,2-butadiene, 1,4-butadiene, 1-butene, isobutylene and the like. The olefinic compound of -6 is homopolymerized or copolymerized as a main component, or (2) a diene compound such as butadiene or isoprene is homopolymerized or copolymerized, or the olefinic compound is copolymerized. Thereafter, it can be obtained by a method such as hydrogenation.

  Among these, polyisobutylene, hydrogenated polyisoprene, and hydrogenated polybutadiene are preferable because it is easy to introduce a functional group at the terminal, easily control the molecular weight, and increase the number of terminal functional groups. Furthermore, since polyisobutylene has liquid or fluidity, it is easy to handle, and since it does not contain any carbon-carbon unsaturated bonds other than aromatic rings in the main chain, there is no need for hydrogenation and it is particularly excellent in weather resistance. preferable. In the polyisobutylene, all of the monomer units may be formed from isobutylene units, or the monomer units copolymerizable with isobutylene are preferably 50 wt% or less, more preferably 30 wt% in polyisobutylene. % Or less, particularly preferably 10% by weight or less.

  Examples of such monomer components for hydrocarbon polymerization include olefins having 4 to 12 carbon atoms, vinyl ethers, aromatic vinyl compounds, vinyl silanes, and allyl silanes. For example, 1-butene, 2-butene, 2-methyl-1-butene, 3-methyl-1-butene, pentene, 4-methyl-1-pentene, hexene, vinylcyclohexene, methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, styrene , Α-methylstyrene, dimethylstyrene, monochlorostyrene, dichlorostyrene, β-pinene, indene, vinyltrichlorosilane, vinylmethyldichlorosilane, vinyldimethylchlorosilane, vinyldimethylmethoxysilane, vinyltrimethylsilane, divinyldichlorosilane, divinyldimethoxysilane , Divinyldimethylsilane, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, trivinylmethylsilane, tetravinylsilane, allyltrichlorosilane, allyl Examples include methyldichlorosilane, allyldimethylchlorosilane, allyldimethylmethoxysilane, allyltrimethylsilane, diallyldichlorosilane, diallyldimethoxysilane, diallyldimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropylmethyldimethoxysilane. .

  In the hydrogenated polyisoprene, hydrogenated polybutadiene, and other hydrocarbon polymers, as in the case of the above polyisobutylene, other monomer units may be contained in addition to the main monomer unit. Good.

(Vinyl polymers other than hydrocarbon polymers)
The vinyl polymer other than the hydrocarbon polymer in the present invention is not particularly limited as the vinyl monomer constituting the main chain, and various types can be used. Specifically, (meth) acrylic acid monomers, aromatic vinyl monomers, fluorine-containing vinyl monomers, silicon-containing vinyl monomers, maleimides such as various monomers described in paragraph [0018] of JP-A-2005-232419 Examples thereof include vinyl monomers, nitrile group-containing vinyl monomers, amide group-containing vinyl monomers, vinyl esters, alkenes, conjugated dienes, vinyl chloride, vinylidene chloride, allyl chloride, and allyl alcohol. These may be used alone or a plurality of these may be copolymerized. Here, (meth) acrylic acid represents acrylic acid and / or methacrylic acid.

  The main chain of the vinyl polymer other than the hydrocarbon polymer used in the curable composition of the present invention is a (meth) acrylic monomer, an acrylonitrile monomer, an aromatic vinyl monomer, a fluorine-containing vinyl monomer, and It is preferable that it is produced mainly by polymerizing at least one monomer selected from the group consisting of silicon-containing vinyl monomers. Here, “mainly” means that 50 mol% or more of the monomer units constituting the vinyl polymer (b) is the above monomer, and preferably 70 mol% or more.

  Of these, aromatic vinyl monomers and / or (meth) acrylic acid monomers are preferred, acrylic acid ester monomers and / or methacrylic acid ester monomers are more preferred, and acrylic acid ester monomers are even more preferred from the physical properties of the product. . Particularly preferred acrylic ester monomers include alkyl acrylate monomers, specifically ethyl acrylate, 2-methoxyethyl acrylate, stearyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic acid. 2-methoxybutyl.

  In the present invention, these preferred monomers may be copolymerized with other monomers, and further block copolymerized, and in this case, these preferred monomers may be contained in a weight ratio of 40% by weight or more. preferable.

  The vinyl polymer used in the present invention can be obtained by various polymerization methods, and is not particularly limited, but is preferably a radical polymerization method from the viewpoint of versatility of the monomer, ease of control, etc. Radical polymerization is more preferred. This controlled radical polymerization method can be classified into a “chain transfer agent method” and a “living radical polymerization method” which is a kind of living polymerization. Living radical polymerization, in which the molecular weight and molecular weight distribution of the resulting vinyl polymer can be easily controlled, is further preferred, and atom transfer radical polymerization is particularly preferred from the viewpoint of availability of raw materials and ease of introduction of a functional group at the polymer terminal. The above radical polymerization, controlled radical polymerization, chain transfer agent method, living radical polymerization method, and atom transfer radical polymerization are known polymerization methods. For example, JP-A-2005-232419 and Reference can be made to the description in Japanese Unexamined Patent Publication No. 2006-291073.

  Atom transfer radical polymerization, which is one of the preferred methods for synthesizing vinyl polymers other than hydrocarbon polymers in the present invention, will be briefly described below.

  In atom transfer radical polymerization, an organic halide, particularly an organic halide having a highly reactive carbon-halogen bond (for example, a carbonyl compound having a halogen at the α-position or a compound having a halogen at the benzyl-position), or a sulfonyl halide. A compound or the like is preferably used as an initiator. Specific examples include compounds described in paragraphs [0040] to [0064] of JP-A-2005-232419.

  There is no restriction | limiting in particular as a vinyl-type monomer used in atom transfer radical polymerization, All the vinyl-type monomers mentioned above can be used conveniently.

  Although it does not specifically limit as a transition metal complex used as a polymerization catalyst, Preferably it is a metal complex which uses a periodic table group 7, 8, 9, 10, or 11 element as a central metal, More preferably, it is 0. A transition metal complex having valent copper, monovalent copper, divalent ruthenium, divalent iron, or divalent nickel as a central metal, particularly preferably a copper complex. Specific examples of the monovalent copper compound used to form the copper complex include cuprous chloride, cuprous bromide, cuprous iodide, cuprous cyanide, and oxidized oxide. Cuprous, cuprous perchlorate, and the like. In the case of using a copper compound, 2,2′-bipyridyl or a derivative thereof, 1,10-phenanthroline or a derivative thereof, tetramethylethylenediamine, pentamethyldiethylenetriamine, hexamethyltris (2-aminoethyl) amine, etc. in order to increase the catalytic activity These polyamines are added as ligands.

The polymerization reaction can be carried out without solvent, but can also be carried out in various solvents. It does not specifically limit as a kind of solvent, The solvent of Unexamined-Japanese-Patent No. 2005-232419 Paragraph [0067] is mentioned. These may be used alone or in combination of two or more. Polymerization can also be performed in an emulsion system or a system using supercritical fluid CO ₂ as a medium.
Although superposition | polymerization temperature is not limited, It can carry out in the range of 0-200 degreeC, Preferably, it is the range of room temperature-150 degreeC.

<Polymerizable carbon-carbon double bond introduction method (component (A) and component (B))>
Although the polymerizable carbon-carbon double bond of (A) component and (B) component is not specifically limited, General formula (1)
—OC (O) C (R ^a ) ═CH ₂ (1)
(Wherein R ^a represents a hydrogen atom or an organic group having 1 to 20 carbon atoms)
The (meth) acryloyl group represented by these is preferable.

  The component (A) contains 1.5 or more polymerizable carbon-carbon double bonds on average in the molecule, and the component (B) contains 1 on average polymerizable carbon-carbon double bonds in the molecule. Contains no more. The polymerizable carbon-carbon double bond of the component (A) and the component (B) is preferably at the end of the molecular chain.

(Introduction method to polysiloxane)
Although there is no particular limitation, for example, a hydrolyzable silyl group-containing vinyl compound, a hydrolyzable silyl group-containing (meth) acryloyl compound can be prepared by using an organometal or the like as a terminal silanol-terminated polysiloxane described in Japanese Patent No. 3193866. Examples include a method of hydrolytic condensation reaction.

(Introduction method to polyether)
The method for introducing a polymerizable carbon-carbon double bond into the oxyalkylene polymer is not particularly limited, but <1> a polyoxyalkylene having a hydroxyl terminal is reacted with an acid chloride compound of the general formula (1). <2> a method of reacting a compound of the general formula (1) containing an isocyanate group with a polyoxyalkylene having a hydroxyl terminal, <3> a polyfunctional isocyanate with a polyoxyalkylene having a hydroxyl terminal, and A method of reacting a vinyl monomer containing a hydroxyl group, <4> a polysilyl group having a hydrosilylation capable double bond terminal (for example, allyl group terminal) polyoxyalkylene, and a polyfunctional type hydrosilyl compound, and further reacting with allyl (meth) acrylate, etc. There is a method of reacting a compound capable of hydrosilylation. The methods <2>, <3>, and <4> are preferable from the viewpoint of the simplicity of the reaction, and the methods <2> and <3> are more preferable from the viewpoint of the stability of the reaction.

(Introduction method to vinyl polymer)
As a method for introducing a polymerizable carbon-carbon double bond into the vinyl polymer, a known method can be used. For example, the method described in paragraphs [0080] to [0091] of JP-A-2004-203932 can be mentioned, and the following method is preferable.

(Introduction method 1)
A method of replacing the terminal halogen group of the vinyl polymer of the general formula (2) with a compound having a polymerizable carbon-carbon double bond of the general formula (3).
-CR ¹ R ² X (2)
(In the formula, R ¹ and R ² are groups bonded to an ethylenically unsaturated group of a vinyl monomer. X represents chlorine, bromine, or iodine.)
M ^{+ −} OC (O) C (R) ═CH ₂ (3)
(In the formula, R represents hydrogen or an organic group having 1 to 20 carbon atoms. M ⁺ represents an alkali metal or a quaternary ammonium ion.)

  The vinyl polymer having a terminal structure represented by the general formula (2) is a method of polymerizing a vinyl monomer using the above-described organic halide or sulfonyl halide compound as an initiator and a transition metal complex as a catalyst, or Although it is produced by a method of polymerizing a vinyl monomer using a halogen compound as a chain transfer agent, the former is preferred.

Formula is not particularly restricted but includes compounds represented by (3), specific examples of R, for _{example, -H, -CH 3, -CH 2} CH 3, - (CH 2) n CH 3 (n is It represents an integer of _{2~19), - C 6 H 5} , -CH 2 OH, -CN, etc., and is preferably -H, -CH _3.

M ⁺ is a counter cation of an oxyanion, and examples of M ⁺ include alkali metal ions, specifically lithium ions, sodium ions, potassium ions, and quaternary ammonium ions. Examples of the quaternary ammonium ion include tetramethylammonium ion, tetraethylammonium ion, tetrabenzylammonium ion, trimethyldodecylammonium ion, tetrabutylammonium ion, and dimethylpiperidinium ion, preferably sodium ion and potassium ion. The usage-amount of the oxyanion of General formula (3) becomes like this. Preferably it is 1-5 equivalent with respect to the halogen group of General formula (2), More preferably, it is 1.0-1.2 equivalent. The solvent for carrying out this reaction is not particularly limited but is preferably a polar solvent because it is a nucleophilic substitution reaction. For example, tetrahydrofuran, dioxane, diethyl ether, acetone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, hexamethylphosphoric Triamide, acetonitrile, etc. are used. Although the temperature which performs reaction is not limited, Generally it is 0-150 degreeC, In order to hold | maintain a polymeric terminal group, Preferably it carries out at room temperature-100 degreeC.

(Introduction method 2)
A method of reacting a compound represented by the general formula (4) with a vinyl polymer having a hydroxyl group at the terminal.
XC (O) C (R) = CH ₂ (4)
(In the formula, R represents hydrogen or an organic group having 1 to 20 carbon atoms. X represents chlorine, bromine, or a hydroxyl group.)

(Introduction method 3)
A method in which a diisocyanate compound is reacted with a vinyl polymer having a hydroxyl group at a terminal, and a residual isocyanate group is reacted with a compound represented by the following general formula 5.
HO-R'- OC (O) C (R) = CH ₂ (5)
(In the formula, R represents hydrogen or an organic group having 1 to 20 carbon atoms. R ′ represents a divalent organic group having 2 to 20 carbon atoms.)

  Among these methods, (Introduction method 1) is most preferable because it is easy to control.

<< (C) component >>
The adhesive for display panels of this invention contains a photoinitiator as (C) component, and is hardened | cured by irradiation of an energy ray. As a photoinitiator, a photoradical initiator, a photoanion initiator, a near-infrared photoinitiator, etc. are mentioned, A photoradical initiator and a photoanion initiator are preferable, and a photoradical initiator is particularly preferable.

  Examples of the photo radical initiator include acetophenone, propiophenone, benzophenone, xanthol, fluorin, benzaldehyde, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-methylacetophenone, 3-pentylacetophenone, 2, 2-diethoxyacetophenone, 4-methoxyacetophenone, 3-bromoacetophenone, 4-allylacetophenone, p-diacetylbenzene, 3-methoxybenzophenone, 4-methylbenzophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4 -Chloro-4'-benzylbenzophenone, 3-chloroxanthone, 3,9-dichloroxanthone, 3-chloro-8-nonylxanthone, benzoin, benzoy Methyl ether, benzoin butyl ether, bis (4-dimethylaminophenyl) ketone, benzylmethoxy ketal, 2-chlorothioxanthone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl- Phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl -2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, dibenzoyl, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -Phenylphosphine oxide, bis (2,6-dimethoxybenzo Le) -2,4,4-trimethyl - pentyl phosphine oxide, 2,4,6-trimethylbenzoyl - diphenyl - phosphine OY side, and the like.

  Examples of the photoanion initiator include 1,10-diaminodecane, 4,4′-trimethylenedipiperazine, carbamates and derivatives thereof, cobalt-amine complexes, aminooxyiminos, ammonium borates and the like. .

  These photopolymerization initiators may be used alone or in combination of two or more, or may be used in combination with other compounds.

  Specific examples of combinations with other compounds include combinations with amines such as diethanolmethylamine, dimethylethanolamine, and triethanolamine, and combinations with iodonium salts such as diphenyliodonium chloride, methylene blue, and the like. Examples include those combined with a dye and an amine.

  In addition, when using the said photoinitiator, polymerization inhibitors, such as hydroquinone, hydroquinone monomethyl ether, benzoquinone, para tertiary butyl catechol, can also be added as needed.

  Although there is no restriction | limiting in particular in the addition amount of (C) component, From the point of sclerosis | hardenability and storage stability, when the total weight of (A) component and (B) component is 100 weight part, 0.001-10 weight Part is preferred.

<< (D) component >>
The adhesive for display panels of the present invention uses hydrophilic silica having a specific surface area of 200 m ² / g or more as the component (D). Hydrophilic silica is obtained by a production method such as a sedimentation method, a gel method, a combustion method, or an arc method. Hydrophilic silica is not subjected to a hydrophobic treatment, and has many hydrophilic groups such as hydroxyl groups and silanol groups on the surface. Since there are many hydrophilic groups on the surface, 50% or more of the vinyl monomers used in the (A) component and (B) component use monomers with high polarity such as (meth) acrylic acid monomers. In this case, thixotropy is greatly expressed.

(D) The specific surface area of the hydrophilic silica of a component is 200 m < ² > / g or more. When it is less than 200 m ² / g, it is difficult to disperse, and the display panel adhesive sometimes becomes cloudy.
Moreover, content of the hydrophilic silica of (D) component is 4 to 20 weight part when the sum total of (A) component and (B) component is 100 weight part. If it is less than 4 parts by weight, the thixotropy is insufficient, and the adhesive for display panel may leak after bonding. When the amount is more than 20 parts by weight, the display panel adhesive may become cloudy.

<< Compounding agent >>
In the curable composition of the present invention, various compounding agents may be added according to the intended physical properties.

<Polymerizable monomer>
A monomer can be added to the display panel adhesive of the present invention within a range not impairing the effects of the present invention. A monomer having a radical polymerizable group or a monomer having an anion polymerizable group is preferable from the viewpoint of curability.

  Examples of the radical polymerizable group include (meth) acryloyl group such as (meth) acryl group, styrene group, acrylonitrile group, vinyl ester group, N-vinylpyrrolidone group, acrylamide group, conjugated diene group, vinyl ketone group, and chloride. A vinyl group etc. are mentioned.

  Among these, those having a (meth) acryloyl group similar to the vinyl polymer used in the present invention are preferable.

  Examples of the anionic polymerizable group include a (meth) acryloyl group such as a (meth) acryl group, a styrene group, an acrylonitrile group, an N-vinylpyrrolidone group, an acrylamide group, a conjugated diene group, and a vinyl ketone group. Among these, those having a (meth) acryloyl group similar to the vinyl polymer used in the present invention are preferable.

  Specific examples of the monomer include those described in paragraphs [0123] to [0131] of JP-A-2006-265488.

  Among the above, a monomer having a (meth) acryloyl group is preferable. Moreover, when using a monomer for the improvement of surface curability and the viscosity reduction for workability | operativity, it is preferable that molecular weight is 1000 or less and compatibility is favorable.

  The amount of the polymerizable monomer used is 1 when the total weight of the component (A) and the component (B) is 100 parts by weight from the viewpoint of improving surface curability, imparting toughness, and workability by reducing viscosity. -200 parts are preferable and 5-100 parts are more preferable.

<Adhesive agent>
An adhesiveness-imparting agent can be added to the curable composition of the present invention for the purpose of further improving the substrate adhesion. Examples of the adhesiveness-imparting agent include a crosslinkable silyl group-containing compound and a vinyl group having a polar group. A monomer is preferable, and further, a silane coupling agent and an acidic group-containing vinyl monomer are preferable. Specific examples thereof include the adhesion-imparting agent described in paragraph [0184] of JP-A-2005-232419.

  As silane coupling agents, other than carbon atoms and hydrogen atoms, such as epoxy groups, isocyanate groups, isocyanurate groups, carbamate groups, amino groups, mercapto groups, carboxyl groups, halogen groups, (meth) acryl groups, etc. in the molecule. A silane coupling agent having both an organic group having an atom and a crosslinkable silyl group can be used.

  Specific examples thereof include a silane coupling agent having both a crosslinkable silyl group and an organic group having atoms other than carbon atoms and hydrogen atoms described in paragraph [0185] of JP-A-2005-232419. Among these, alkoxysilanes having an epoxy group or a (meth) acryl group in the molecule are more preferable from the viewpoint of curability and adhesiveness.

  As a vinyl monomer having a polar group, as a carboxyl group-containing monomer, (meth) acrylic acid, acryloxypropionic acid, citraconic acid, fumaric acid, itaconic acid, crotonic acid, maleic acid or esters thereof, And maleic anhydride and derivatives thereof. Examples of the ester of the galboxyl group-containing monomer include 2- (meth) acryloyloxyethyl succinic acid and 2- (meth) acryloyloxyethyl hexahydrophthalic acid. Examples of the sulfonic acid group-containing monomer include vinyl sulfonic acid, (meth) acryl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, vinyl benzene sulfonic acid, 2-acrylamido-2-methylpropane sulfone, and salts thereof. Can be mentioned. Furthermore, as the phosphoric acid group-containing monomer, 2-((meth) acryloylcyethyl phosphate), 2- (meth) acryloyloxypropyl phosphate, 2- (meth) acryloyloxy-3-chloropropyl phosphate, 2 -(Meth) acryloyloxyethyl phenyl phosphate and the like. Of these, phosphate group-containing monomers are preferred. The monomer may have two or more polymerizable groups.

  Specific examples of the adhesion-imparting agent other than the silane coupling agent and the polar group-containing vinyl monomer are not particularly limited. For example, epoxy resins, phenol resins, modified phenol resins, cyclopentadiene-phenol resins, xylene resins , Coumarone resin, petroleum resin, terpene resin, terpene phenol resin, rosin ester, rosin ester resin sulfur, alkyl titanates, aromatic polyisocyanate and the like.

  The adhesiveness-imparting agent is preferably blended in an amount of 0.01 to 20 parts by weight when the total weight of the component (A) and the component (B) is 100 parts by weight. If the amount is less than 0.01 part by weight, the effect of improving the adhesiveness is small, and if it exceeds 20 parts by weight, the physical properties of the cured product tend to decrease. Preferably it is 0.1-15 weight part, More preferably, it is 0.5-10 weight part.

  The adhesiveness-imparting agent may be used alone or in combination of two or more.

<Plasticizer>
A plasticizer can be mix | blended with the curable composition of this invention as needed.
Although it does not specifically limit as a plasticizer, For example, the plasticizer of Unexamined-Japanese-Patent No. 2005-232419 Paragraph [0173] is mentioned by the objectives, such as adjustment of a physical property and adjustment of a property. Among these, polyester plasticizers and vinyl polymers are preferable because the effect of reducing the viscosity is remarkable and the volatilization rate during the heat resistance test is low. Further, by adding a polymer plasticizer which is a polymer having a number average molecular weight of 200 to 15000, the viscosity of the curable composition and the tensile strength and elongation of the cured product obtained by curing the curable composition are added. The mechanical properties such as the above can be adjusted, and the initial physical properties can be maintained over a long period of time as compared with the case where a low molecular plasticizer which is a plasticizer not containing a polymer component in the molecule is used. Although not limited, the polymer plasticizer may or may not have a functional group.

  The number average molecular weight of the polymer plasticizer is preferably 800 to 10000, more preferably 1000 to 8000. If the molecular weight is too low, the plasticizer may flow out over time when exposed to heat or in contact with a liquid, and the initial physical properties may not be maintained over a long period of time. Moreover, when molecular weight is too high, a viscosity will become high and there exists a tendency for workability | operativity to fall.

  Of these polymer plasticizers, those compatible with the vinyl polymer are preferred. Of these, vinyl polymers are preferred from the viewpoints of compatibility, weather resistance, and heat aging resistance. Among the vinyl polymers, (meth) acrylic polymers are preferable, and acrylic polymers are more preferable. Examples of the method for synthesizing the acrylic polymer include those obtained by conventional solution polymerization and solvent-free acrylic polymers. The latter acrylic plasticizer does not use a solvent or a chain transfer agent, and is a high-temperature continuous polymerization method (USP 4414370, JP 59-6207, JP-B-5-58005, JP 1-331522, USP 5010166). It is more preferable for the purpose of the present invention. Examples thereof include, but are not limited to, Toagosei UP series and the like (see the Industrial Materials October 1999 issue). Of course, the living radical polymerization method can also be mentioned as another synthesis method. According to this method, the molecular weight distribution of the polymer is narrow and the viscosity can be lowered, and the atom transfer radical polymerization method is more preferable, but it is not limited thereto.

  The molecular weight distribution of the polymer plasticizer is not particularly limited, but is preferably narrow and is preferably less than 1.8. 1.7 or less is more preferable, 1.6 or less is still more preferable, 1.5 or less is more preferable, 1.4 or less is especially preferable, and 1.3 or less is the most preferable.

The plasticizer containing the above-mentioned polymer plasticizer may be used alone or in combination of two or more, but is not necessarily required. Further, if necessary, a high molecular plasticizer may be used, and a low molecular plasticizer may be further used in a range that does not adversely affect the physical properties.
These plasticizers can also be blended at the time of polymer production.

  The amount of the plasticizer used is not limited, but when the total weight of the component (A) and the component (B) is 100 parts by weight, it is preferably 1 to 100 parts by weight, more preferably 5 to 50 parts by weight. It is. If the amount is less than 1 part by weight, the effect as a plasticizer tends to be hardly exhibited, and if it exceeds 100 parts by weight, the mechanical strength of the cured product tends to be insufficient.

<Antioxidant>
Various antioxidants may be used in the curable composition of the present invention as necessary. These antioxidants include p-phenylenediamine-based antioxidants, amine-based antioxidants, hindered phenol-based antioxidants, secondary antioxidants such as phosphorus-based antioxidants, sulfur-based antioxidants, etc. Is mentioned.

<Reactive diluent>
In addition to the plasticizer, a reactive diluent described below may be used in the present invention. If a low-boiling compound that can be volatilized during curing is used as a reactive diluent, it will change shape before and after curing, or it may adversely affect the environment due to volatiles. An organic compound having a boiling point of 100 ° C. or higher is particularly preferable.

  Specific examples of the reactive diluent include 1-octene, 4-vinylcyclohexene, allyl acetate, 1,1-diacetoxy-2-propene, methyl 1-undecenoate, 8-acetoxy-1,6-octadiene and the like. However, it is not limited to these.

  The addition amount of the reactive diluent is preferably 0.1 to 100 parts by weight, more preferably 0.5 to 70 parts by weight, when the total weight of the component (A) and the component (B) is 100 parts by weight. More preferably, it is 1-50 weight part.

<Light stabilizer>
You may add a light stabilizer to the curable composition of this invention as needed. Various types of light stabilizers are known, and are described in, for example, “Antioxidant Handbook” issued by Taiseisha, “Degradation and Stabilization of Polymer Materials” (235-242) issued by CM Chemical Co., Ltd. Although various things are mentioned, it is not necessarily limited to these.

  Although it is not particularly limited, among the light stabilizers, an ultraviolet absorber is preferable, and specifically, Tinuvin P, Tinuvin 234, Tinuvin 320, Tinuvin 326, Tinuvin 327, Tinuvin 329, Tinuvin 213 Benzotriazole compounds such as TINUVIN 1577, benzophenone compounds such as CHIMASSORB 81, benzoate compounds such as TINUVIN 120 (manufactured by Ciba Geigy Japan), hostabin PR-25 And α, β-unsaturated carboxylic acid ester compounds such as Hostabin B-CAP (manufactured by Clariant), oxalic acid amide compounds such as Hostabin VSU, and the like.

  Further, hindered amine compounds are also preferable, and specific examples of such compounds include those described in JP-A-2006-274084, but are not limited thereto.

  Furthermore, since the combination of the ultraviolet absorber and the hindered amine compound may exhibit more effect, it is not particularly limited, but may be used in combination, and it is preferable to use in combination.

  The light stabilizer may be used in combination with the above-described antioxidant, and it is particularly preferable because the effect is further exhibited and the weather resistance may be improved. Tinuvin C353, Tinuvin B75 (all of which are manufactured by Ciba Geigy Japan, Inc.) in which a light stabilizer and an antioxidant are mixed in advance may be used.

  The amount of the light stabilizer used is preferably in the range of 0.1 to 10 parts by weight when the total weight of the component (A) and the component (B) is 100 parts by weight. If it is less than 0.1 parts by weight, the effect of improving the weather resistance is small, and if it exceeds 10 parts by weight, there is no great difference in the effect, which is economically disadvantageous.

<Solvent>
A solvent can be mix | blended with the curable composition of this invention as needed. Solvents that can be blended include, for example, aromatic hydrocarbon solvents such as toluene and xylene; ester solvents such as ethyl acetate, butyl acetate, amyl acetate, and cellosolve; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and diisobutyl ketone A solvent etc. are mentioned. These solvents may be used during production of the polymer.

<Other additives>
Various additives may be added to the curable composition of the present invention as necessary for the purpose of adjusting various physical properties of the curable composition or its cured product. Examples of such additives include, for example, flame retardants, anti-aging agents, radical inhibitors, metal deactivators, ozone degradation inhibitors, phosphorus peroxide decomposers, lubricants, pigments, foaming agents, etc. Can be given. These various additives may be used alone or in combination of two or more. Specific examples of such additives include, for example, each specification of JP-B-4-69659, JP-B-7-108928, JP-A-63-254149, JP-A-64-22904, and the like. It is described in.

<< Adhesive for display panel >>
The curable composition of the present invention can be prepared as a one-pack type in which all blending components are blended and sealed in advance, and the A liquid from which only the polymerization initiator is removed, and the initiator as a filler, a plasticizer, a solvent, and the like. It can also be prepared as a two-component type in which the mixed B liquid is mixed immediately before molding.

<Maximum coarse particles>
The maximum coarse particle of the adhesive for display panels of the present invention is 30 μm or less. When the maximum coarse particle is 30 μm or more, the desired viscosity may not be adjusted.

  The largest coarse particle is measured using a grind gauge.

<Viscosity>
The viscosity P1 at 25 ° C. at the shear rate D1 = 2.1 of the display panel adhesive is 31,000 mPa · s or more, and the viscosity P2 at 25 ° C. at the shear rate D2 = 21 is less than 30,000 mPa · s. preferable. After spreading the display panel adhesive between the two objects to be bonded together, UV curing is performed to eliminate the fluidity of the display panel adhesive, and the two objects are fixed, but P1 is 31,000 mPa · s. If it is less than that, the adhesive for the display panel flows after the adhesive for the display panel is spread and is cured by UV, and the adhesive for the display panel flows out from the ends of the two objects to contaminate the surroundings. There was a thing. When P2 is 30,000 mPa · s or more, the display panel adhesive may not spread uniformly between the two objects, and bubbles may be bitten. In particular, after narrowing the distance between the substrate to which the adhesive for display panel is applied and the object to be bonded, and spreading the adhesive for display panel between the object to be bonded and the object to be bonded, energy rays (UV) In the manufacturing method of the display panel which hardens the adhesive agent for display panels and fixes a to-be-coated body and a to-be-bonded body, an effect becomes remarkable. When the distance between the application body to which the adhesive for display panel is applied and the object to be bonded is reduced, the adhesive for display panel hangs down from the application body by its own weight. The tip of the convex part of the adhesive for the display panel is grounded to the object to be bonded, and the distance between the object to be bonded and the object to be bonded is further narrowed to spread the adhesive for the display panel between the object to be bonded and the object to be bonded. (Fig. 1). When the viscosity P1 at 25 ° C. at the shear rate D1 = 2.1 is 31,000 mPa · s or more, the display panel adhesive is sufficiently spread between the coated body and the bonded body (FIG. 1 (3) ) Since the display panel adhesive does not flow, the surroundings are not contaminated. When the viscosity P2 at 25 ° C. at the shear rate D2 = 21 is less than 30,000 mPa · s, the adhesive for display panel can be spread uniformly when spread between the coated body and the bonded body.

<< Method of applying adhesive for display panel >>
The method for applying the adhesive for the display panel can be broadly classified according to whether the two objects to be bonded are first fixed or not.

  When the two objects to be bonded are first fixed, the display panel adhesive can be pushed in between them. In addition, the display panel adhesive can be sucked in a vacuum.

  When the two objects to be bonded are not first fixed, the display panel adhesive can be applied to one of the objects and then bonded to the other object. Moreover, after apply | coating the adhesive for display panels to both target objects, a target object can be bonded together. A dam can be provided around the application region before the display panel adhesive is applied to the object.

  In particular, after narrowing the distance between the substrate to which the adhesive for display panel is applied and the object to be bonded, and widening the adhesive for display panel between the object to be bonded and the object to be bonded, use energy rays for the display panel. The manufacturing method of the display panel which hardens an adhesive agent and fixes a to-be-coated body and a to-be-bonded body is preferable at the point which can simplify an apparatus.

  Further, the application method is not particularly limited, but it is preferable that a nozzle having a circular or square tip is used, and the coating can be performed uniformly while keeping the distance between the object to be applied and the nozzle tip constant.

<< Curing method >>
(C) Since a photoinitiator is used as a component, it can be hardened by irradiating light or an electron beam with an energy ray source. Although there is no limitation in particular as an energy beam source, According to the property of the photoinitiator to be used, a high pressure mercury lamp, a low pressure mercury lamp, an electron beam irradiation apparatus, a halogen lamp, a light emitting diode, a semiconductor laser, a metal halide etc. are mentioned, for example. The integrated light amount is preferably 500 mJ / cm ² or more, but the integrated light amount can be determined from the hardness, the conversion rate of the reactive double bond, and the curing behavior.

  Energy rays can be irradiated from the coated body side and / or the bonded body side of the bonded body obtained by bonding the coated body and the bonded body, and can also be irradiated from the side surface of the bonded body.

<< Usage >>
The adhesive for display panel of the present invention is a touch panel and a transparent cover material, a liquid crystal display module or an organic EL module and a transparent cover material, a liquid crystal display module or an organic material in a display panel of an image display device such as a mobile phone, a tablet PC or a personal computer. It can be used for adhesive applications with high transparency such as bonding to an EL module.

  When it is a member different from the touch panel, the touch panel is disposed on a display module such as a liquid crystal display module or an organic EL module, and a transparent cover material is disposed on the touch panel. When the touch panel function is incorporated in the liquid crystal display module, a transparent cover material is disposed on the liquid crystal module.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.

  In the following Examples, “number average molecular weight” and “molecular weight distribution (ratio of weight average molecular weight to number average molecular weight)” were calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC). However, a GPC column filled with polystyrene cross-linked gel (shodex GPC K-804 and K-802.5; Showa Denko KK) and chloroform as a GPC solvent were used.

The “number of acryloyl groups introduced per molecule of polymer” was calculated from the number average molecular weight determined by ¹ H-NMR analysis and GPC. (However, ¹ H-NMR was measured at 23 ° C. using Bruker ASX-400 (400 MHz) and deuterated chloroform as a solvent.)

<Production of (meth) acrylic polymer having (meth) acryloyloxy group at terminal>
(Production Examples 1, 2, and 3)
Table 1 shows the amount of each raw material used.
(1) Polymerization step n-butyl acrylate (premixed n-butyl acrylate) was deoxygenated. The inside of the stainless steel reaction vessel equipped with a stirrer was deoxygenated, cuprous bromide and a part of all n-butyl acrylate (described as initial charge monomer in Table 1) were charged and stirred with heating. Acetonitrile (described as “Acetonitrile for polymerization” in Table 1) and diethyl-2,5-dibromoadipate (DBAE) or ethyl 2-bromobutyrate (EBB) as an initiator are added and mixed, and the temperature of the mixture is brought to about 80 ° C. At the adjusted stage, pentamethyldiethylenetriamine (hereinafter abbreviated as triamine) was added to initiate the polymerization reaction. The remaining n-butyl acrylate (described as an additional monomer in Table 1) was sequentially added to proceed the polymerization reaction. During the polymerization, triamine was appropriately added to adjust the polymerization rate. The total amount of triamine used during the polymerization is shown in Table 1 as a triamine for polymerization. As the polymerization proceeds, the internal temperature rises due to the heat of polymerization, so the polymerization was allowed to proceed while adjusting the internal temperature to about 80 ° C to about 90 ° C.
(2) Oxygen treatment step When the monomer conversion rate (polymerization reaction rate) was about 95% or more, an oxygen-nitrogen mixed gas was introduced into the reaction vessel gas phase. While maintaining the internal temperature at about 80 ° C. to about 90 ° C., the reaction solution was heated and stirred for several hours to bring the polymerization catalyst in the reaction solution into contact with oxygen. Acetonitrile and unreacted monomer were removed by devolatilization under reduced pressure to obtain a concentrate containing a polymer. The concentrate was markedly colored.
(3) First crude purification Butyl acetate was used as a diluent solvent for the polymer. The concentrate of (2) is diluted with about 100 to 150 kg of butyl acetate with respect to 100 kg of the polymer, and a filter aid (Radiolite R900, manufactured by Showa Chemical Industry Co., Ltd.) and / or an adsorbent (KYOWARD 700SEN, Kyoward 500SH) was added. After introducing an oxygen-nitrogen mixed gas into the gas phase part of the reaction vessel, the mixture was heated and stirred at about 80 ° C. for several hours. Insoluble catalyst components were removed by filtration. The filtrate was colored and slightly turbid due to the polymerization catalyst residue.
(4) Second crude purification The filtrate was charged into a stainless steel reaction vessel equipped with a stirrer, and adsorbents (Kyoward 700SEN, Kyoward 500SH) were added. After introducing an oxygen-nitrogen mixed gas into the gas phase and heating and stirring at about 100 ° C. for several hours, insoluble components such as an adsorbent were removed by filtration. The filtrate was almost clear and clear. The filtrate was concentrated to obtain an almost colorless and transparent polymer.
(5) (Meth) acryloyl group introduction step 100 kg of polymer is dissolved in about 100 kg of N, N-dimethylacetamide (DMAC), potassium acrylate (about 2 molar equivalents relative to terminal Br group), thermal stabilizer (H -TEMPO: 4-hydroxy-2,2,6,6-tetramethylpiperidine-n-oxyl) and an adsorbent (Kyoward 700SEN) were added, and the mixture was heated and stirred at about 70 ° C for several hours. DMAC was distilled off under reduced pressure, the polymer concentrate was diluted with about 100 kg of toluene with respect to 100 kg of the polymer, a filter aid was added, the solid content was filtered off, the filtrate was concentrated, and an acryloyl group was added to the end. Polymers [P1], [P2] and [P3] having Table 1 shows the number of acryloyl groups introduced per molecule of the obtained polymer, the number average molecular weight, and the molecular weight distribution.

<Evaluation method>
(viscosity)
The viscosity was measured after putting the adhesive for a display panel into a sample bottle and leaving it to be sealed at 25 ° C. for 24 hours or more. The shear rate (1 / s) in the rotational viscometer (coaxial cylindrical type) is the radius R1 (mm) of the viscometer rotor, the inner diameter R2 (mm) of the glass bottle containing the display panel adhesive, and the rotational speed of the rotor. It calculated from the following formula using N (rpm).
Shear rate (D) = 0.2094 N / (1- (R1 / R2) ² )
In this application, using a rotor with R1 of 1.5 mm, putting an adhesive for a display panel in a glass bottle with an inner diameter of 16 mm, the viscosity when N is 10 rpm (shear rate is 2.1) and 100 rpm (shear rate is 21), It measured using the B-type viscosity meter at 25 degreeC.

(Appearance of pasted sample)
An adhesive for a display panel was hung on alkali glass having a thickness of 1 mm and a radius of 2.5 cm. The glass was turned over and brought close to the same glass prepared below, and the adhesive for the display panel was spread evenly and left for 20 seconds. Then, irradiation with UV light was started. UV light irradiation is performed by irradiating UV light with an integrated light amount of 3000 mJ / cm ² using a UV irradiation device (Light Hammer 6; manufactured by Fusion UV system Japan), and the thickness of the cured layer of the adhesive for the display panel is 200 μm. A pasted sample was obtained. The appearance of the obtained bonded sample at room temperature was visually confirmed after leaving the bonded sample prepared by the above method at 25 ° C. for 24 hours or more.

(Liquid spread)
In the pasted sample preparation, when the adhesive for a display panel was spread evenly, the one that foams were bitten was regarded as “insufficient”, and the one that was not chewed was designated as “sufficient”.

(Liquid leak)
In the pasted sample preparation, the display panel adhesive was spread evenly to the edge of the alkali glass, then left for 20 seconds, and after the UV light irradiation ended, the one that flowed to the edge of the alkali glass was regarded as “leaked” and flowed What did not exist was defined as “no leak”.

Example 1
(A) 20 parts by weight of the polymer [P1] obtained in Production Example 1 and 10 parts by weight of the polymer [P2] obtained in Production Example 2 were obtained in Production Example 3 as (B) components. After mixing 70 parts by weight of the polymer [P3], 6.25 parts by weight of hydrophilic silica Aerosil 300 (surface treatment: untreated specific surface area: 300 m ² / g) (Evonik) as component (D) is mixed. And the dispersion liquid which grind | pulverized hydrophobic silica with the three rolls and was disperse | distributed uniformly was acquired. In the dispersion, as component (C), DAROCUR 1173 (2-hydroxy-2-methyl-1-phenyl-1-propan-1-one (manufactured by Ciba Specialty Chemicals)) 0.8 part by weight and TPO (2 , 4,6-Trimethylbenzoyl-diphenyl-phosphine oxide (BASF) 0.1 part by weight was mixed. At that time, 7 parts by weight of HOA (2-hydroxyethyl-acrylate (manufactured by Osaka Organic Chemical Industry)), 10 parts by weight of ISTA (isostearyl acrylate (manufactured by Osaka Organic Chemical Industry)), KE-100 (Arakawa Chemical Industries, Ltd.) 10 parts by weight and 15 parts by weight of RS-107S (manufactured by Adeka) were mixed together. Thereafter, the particle diameter of the largest coarse particles by a grind gauge was 30 μm or less, and the silica dispersibility was good. Thereafter, defoaming was performed to obtain a display panel adhesive.

  The viscosity at the shear rate (D1) 2.1 of the adhesive for display panel (measurement temperature 25 ° C.) is 170,000 mPa · s, and the viscosity at the shear rate (D2) 21 of the adhesive for display panel (measurement temperature 25). ° C) was 28,600 mPa · s. The appearance (normal temperature) of the pasted sample was transparent. Moreover, the liquid spread sufficiently during the preparation of the bonded sample, and no liquid leakage occurred from the end of the sample. Table 2 summarizes the results.

(Example 2)
A method similar to that of Example 1 except that Aerosil 200 (surface treatment: untreated specific surface area: 200 m ² / g) (manufactured by Evonik) as hydrophilic silica was mixed with 4.5 parts by weight of the adhesive for display panel. The display panel adhesive was obtained. Table 2 shows the viscosity, the appearance of the bonded sample, and liquid leakage / spreading.

(Comparative Example 1)
A method similar to Example 1 except that Aerosil 300 (surface treatment: untreated specific surface area: 300 m ² / g) (manufactured by Evonik) as a hydrophilic silica was mixed with 1.5 parts by weight of an adhesive for display panel. The display panel adhesive was obtained.

  The viscosity at the shear rate (D1) 2.1 of the display panel adhesive (measurement temperature 25 ° C.) is 20,000 mPa · s, and the viscosity at the shear rate (D2) 21 of the adhesive for display panel (measurement temperature). 25 ° C.) was 9,000 mPa · s. Although the adhesive for the display panel spread sufficiently during the preparation of the bonded sample, liquid leakage from the sample edge occurred. Table 2 summarizes the results.

(Comparative Example 2)
A display panel adhesive was obtained in the same manner as in Example 1 except that the mixture was not kneaded with a three-roll. The particle size of the largest coarse particles measured with a grind gauge was 30 μm or more, and the silica dispersibility was poor.

  The viscosity at the shear rate (D1) 2.1 of the adhesive for display panel (measurement temperature 25 ° C.) is 15,000 mPa · s, and the viscosity at the shear rate (D2) 21 of the adhesive for display panel (measurement temperature 25). ° C) was 8,000 mPa · s. Although the adhesive for the display panel spread sufficiently during the preparation of the bonded sample, liquid leakage from the sample edge also occurred. Table 2 summarizes the results.

(Comparative Example 3)
Displayed in the same manner as in Example 1 except that 4.5 parts by weight of hydrophilic silica aerosil 130 (surface treatment: untreated specific surface area: 130 m ² / g) (manufactured by Evonik) was mixed with the adhesive for display panel. A panel adhesive was obtained. The obtained adhesive for display panels was cloudy. Table 2 summarizes the results.

(Comparative Example 4)
Display panel in the same manner as in Example 1 except that 10 parts by weight of hydrophobic silica Aerosil RY200S (surface treatment: dimethylpolysiloxane, specific surface area: 130 m ² / g) (Evonik) was mixed with the adhesive for display panel. An adhesive was obtained.

  The viscosity at the shear rate (D1) 2.1 of the adhesive for display panel (measurement temperature 25 ° C.) is 22,000 mPa · s, and the viscosity at the shear rate (D2) 21 of the adhesive for display panel (measurement temperature 25). ° C) was 12,000 mPa · s. Although the adhesive for the display panel spread sufficiently during the preparation of the bonded sample, liquid leakage from the sample edge also occurred. Table 2 summarizes the results.

(Comparative Example 5)
20 parts by weight of the polymer [P1] obtained in Production Example 1 as the component (A) and 10 parts by weight of the polymer [P2] obtained in Production Example 2, and the weight obtained in Production Example 3 as the component (B). Combined [P3] 70 parts by weight, and (C) component, DAROCUR1173 (2-hydroxy-2-methyl-1-phenyl-1-propan-1-one (manufactured by Ciba Specialty Chemicals)) 0.8 part by weight And 0.1 part by weight of TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (BASF)) were mixed. At that time, 7 parts by weight of HOA (2-hydroxyethyl-acrylate (manufactured by Osaka Organic Chemical Industry)), 10 parts by weight of ISTA (isostearyl acrylate (manufactured by Osaka Organic Chemical Industry)), KE-100 (Arakawa Chemical Industries, Ltd.) 10 parts by weight) and 15 parts by weight of RS-107S (manufactured by Adeka) were mixed together and finally defoamed to obtain a display panel adhesive.

  The viscosity at the shear rate (D1) 2.1 of the display panel adhesive (measurement temperature 25 ° C.) is 3,500 mPa · s, and the viscosity at the shear rate (D2) 21 of the adhesive for display panel (measurement temperature). 25 ° C.) was 3,600 mPa · s. The appearance (normal temperature) of the pasted sample was transparent. Moreover, although the liquid spread sufficiently when the bonded sample was produced, liquid leakage occurred from the end of the sample. Table 2 summarizes the results.

  According to the present invention, there are provided an adhesive for a display panel in which an adhesive does not protrude from a member to be bonded with an adhesive, a display panel using the adhesive, and a method for manufacturing a display panel using the adhesive. Can do. In particular, after narrowing the distance between the coated body to which the adhesive is applied and the bonded body, spreading the adhesive between the coated body and the bonded body, the adhesive is cured with energy rays, and the coated body. In the manufacturing method of the display panel that fixes the object to be bonded, the adhesive for the display panel in which the adhesive does not protrude from the object to be bonded and the object to be bonded, before the adhesive is cured with energy rays, is used. Display panel and a method for manufacturing a display panel using an adhesive in the previous period can be provided.

Claims (5)

(A) a polymer containing 1.5 or more polymerizable carbon-carbon double bonds on average in the molecule and having a number average molecular weight (Mn) of 5,000 or more,
(B) a polymer containing an average of 1 or more polymerizable carbon-carbon double bonds in the molecule and having a number average molecular weight (Mn) of 5,000 or more,
(C) a photopolymerization initiator, and (D) hydrophilic silica having a specific surface area of 200 m ² / g or more,
It is an adhesive for display panels including
The component (D) is 4 parts by weight or more and 20 parts by weight or less with respect to a total of 100 parts by weight of the component (A) and the component (B),
The adhesive for display panels whose maximum coarse particle is 30 micrometers or less. The adhesive for a display panel according to claim 1, wherein the component (A) and / or the component (B) is a (meth) acrylic polymer. 3. The display panel according to claim 1, wherein the amount of component (C) is 0.001 to 10 parts by weight, with the total weight of component (A) and component (B) being 100 parts by weight. Adhesive. A display panel using the display panel adhesive according to claim 1. A method for producing a display panel, wherein the adhesive for display panel according to any one of claims 1 to 3 is applied to an object to be coated, and the object to be bonded is bonded to the object.
Narrow the distance between the substrate to which the adhesive for display panel is applied and the object to be bonded, and spread the adhesive for display panel between the object to be bonded and the object to be bonded. The manufacturing method of the display panel which hardens an agent and fixes a to-be-coated body and a to-be-bonded body.