JP5811564B2 - Adhesive film or sheet for air gap filler of display device and display device - Google Patents

Description

The present invention is an adhesive film or the air gap filler adhesive of the display device obtained an electron beam-curable composition used for the sheet formed by applying and irradiating an electron beam to a substrate film or sheet and through which The present invention relates to a display device in which a protection panel and an image display device are integrated, and a touch panel type display device in which a touch panel module and an image display device are integrated, and belongs to these technical fields.
In the following, for the sake of convenience, unless otherwise specified, “ an adhesive film or sheet for an air gap filler of a display device ” is referred to as an “adhesive sheet”. Further, acrylate or methacrylate is represented as (meth) acrylate.

In recent years, portable electronic devices such as mobile phones, smartphones, navigation systems, and netbooks have been widely used. Typical examples of the image display device provided with these electronic devices include a liquid crystal display device, an organic EL display device, and a touch panel display device.
The visibility in these image display devices has been improved year by year due to technological advances, and further, protection from external impacts such as collision and pressing of the liquid crystal display panel has been demanded. Conventionally, in a liquid crystal display device, an air layer (air gap) having a constant thickness is formed between a liquid crystal cell and a transparent protective panel for protecting the liquid crystal cell.

  This air gap is provided for the purpose of providing a buffering characteristic so that the impact is not directly transmitted to the liquid crystal cell when the liquid crystal display device or the touch panel type display device is subjected to an impact at the time of dropping or the like. Especially in the outdoors where sunlight is lit, the light confusion caused by the difference in refractive index from the acrylic plate or glass plate, which is the material of the protective panel, becomes significant, and the brightness and contrast decrease. It is very difficult to see and the visibility is reduced.

  Conventionally, in order to improve the visibility of liquid crystals, it is a common measure to reduce the light confusion by filling the air gap with a transparent optical elastic resin having a refractive index comparable to that of glass or acrylic resin. Proposed.

  Patent Document 1 discloses a transparent optical adhesive (hereinafter, optical clear adhesive: OCA) as a transparent optical elastic resin. However, when a black print is made on the periphery of the cover board, the thickness of the printed part is generally several tens of μm, and there is a step difference from the unprinted part. In the bonding with the silicone-based transparent adhesive sheet, this step could not be sufficiently absorbed. In addition, there is a problem that sheet reattachment (hereinafter referred to as “reworkability”) cannot be performed, and there is a problem in terms of productivity and yield.

On the other hand, Patent Document 2 discloses an ultraviolet (hereinafter referred to as UV) curable composition as a material for forming a transparent optical elastic resin, and is a liquid before curing. The level difference of the part where the black printing is applied on the back of the image (black print part) is efficiently absorbed, and no shadow is produced in the frame part of the image display device, and the design freedom of the design of the image display device is also possible improves.
However, UV does not reach under the black print portion, and the resin curing of the portion becomes insufficient, and there are problems such as product reliability.

  Patent Document 3 discloses a method of adding heat polymerization initiator to UV curable resin to heat after UV irradiation and complement the curing under the black print part. There was a problem of great damage.

  In recent years, UV / moisture curable contact resins have been developed in which the UV light transmitting portion is cured by UV and the UV light non-transmitting portion is cured by moisture in the air. This eliminates the need for curing by heating after UV irradiation, but there is a problem that rework cannot be performed because the film is liquid before curing.

JP 2006-290960 A JP 2008-282000 A JP 2009-186957 A

  As described above, the conventional optical transparent adhesive has a poor step following ability, and the liquid UV curable resin cannot be reworked.

  The present invention has an excellent balance between the transparency of a cured product and the degree of yellowing after a light resistance test, an electron beam curable composition for forming an adhesive sheet that is excellent in reworkability and step followability, and an adhesive obtained from the composition It is an object of the present invention to provide a display device in which a protective panel and an image display device are integrated through a sheet and a cured product of the composition, and a touch panel type display device in which the touch panel module and the image display device are integrated.

As a result of intensive studies to solve the above problems, the present inventors have made urethane (meth) acrylate and one (meth) produced from diol, non-yellowing organic diisocyanate and hydroxyl group-containing (meth) acrylate. The present inventors have found that an electron beam curable composition containing a compound having an acryloyl group can solve the above problems, and have completed the present invention.
Hereinafter, the present invention will be described in detail.

According to the composition of this invention, it is excellent in the balance of the transparency of a hardened | cured material, and the yellowing degree after a light resistance test, and is excellent in rework property and level | step difference followability.
Therefore, the composition and pressure-sensitive adhesive sheet of the present invention can be suitably used as an air gap filler for display devices such as liquid crystal display devices, organic EL display devices and touch panel display devices.

In the present invention, a film or sheet-like substrate (hereinafter collectively referred to as “sheet-like substrate”), an electron beam irradiation cured product of the following composition, and a sheet-like substrate are formed in this order,
The thickness of the electron beam irradiation cured product is 50 to 200 μm.
The present invention relates to an adhesive film or sheet for an air gap filler of a display device .

◆ Hurethane (meth) acrylate (A) (hereinafter simply referred to as “component (A)”), which is a reaction product of hydrogenated polybutadienediol, non-yellowing organic diisocyanate, and hydroxyl group-containing (meth) acrylate, and one ( A compound having a (meth) acryloyl group (B) [hereinafter simply referred to as “component (B)”],
An electron beam curable composition for forming an adhesive film or sheet that does not contain a photopolymerization initiator.
Hereinafter, the present invention will be described in detail. In the present specification, a crosslinked product and a cured product obtained by irradiating the composition with an electron beam are collectively referred to as a “cured product”.

1. Component (A) The component (A) is urethane (meth) acrylate which is a reaction product of hydrogenated polybutadiene diol, non-yellowing organic diisocyanate and hydroxyl group-containing (meth) acrylate.
The said (A) component becomes a thing with a small yellowing degree after a light resistance test by using a non-yellowing type | mold as organic diisocyanate compared with other urethane (meth) acrylates.

As the component (A), a diol and a non-yellowing organic diisocyanate are reacted to produce an isocyanate group-containing compound, and a compound obtained by reacting this with a hydroxyl group-containing (meth) acrylate (hereinafter referred to as “compound A1”), And a compound obtained by simultaneously reacting a diol, a non-yellowing organic diisocyanate and a hydroxyl group-containing (meth) acrylate (hereinafter referred to as “compound A2”), and the compound A1 is preferable because the molecular weight is easily controlled.
As the component (A), both oligomers and polymers can be used, and those having a weight average molecular weight of 1,000 to 50,000 are preferable, and more preferably 3,000 to 30,000.
In the present invention, the weight average molecular weight is a value obtained by converting the molecular weight measured by gel permeation chromatography into polystyrene.

Examples of the diol include hydrogenated polydiene diol, polycarbonate diol, polyester diol, and polyether diol.
In the present invention, the hydrogenated polydiene diol Among these, use because of excellent flexibility of the cured product.

Examples of the hydrogenated polydiene-based diol include a compound having a diol at the terminal of a monomer polymer such as isoprene, 1,3-butadiene, and 1,3-pentadiene, and a diol at the terminal of the copolymer of these monomers. compounds having the like, using a hydrogenated polybutadiene diol. As the hydrogenated polydiene-based diol, a compound having a number average molecular weight of 1,000 to 10,000 is preferable.
Hydrogenated polydiene-based diols are preferred in that they are superior in heat resistance and light resistance compared to non-hydrogenated polydiene diols.

Examples of the polycarbonate diol include a reaction product of a low molecular weight diol, a polyether diol or / and a bisphenol such as bisphenol A and a carbonic acid dialkyl ester such as ethylene carbonate and carbonic acid dibutyl ester.
Here, examples of the low molecular weight diol include ethylene glycol, propylene glycol, cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 1,5-pentanediol, 1,6-hexanediol, and the like.
Examples of polyether diols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and block or random polymer diols such as polyethylene polypropoxy block polymer diols.

  Examples of the polyester diol include the low molecular weight diol or / and the polyether diol, dibasic acids such as adipic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid and terephthalic acid, or anhydrides thereof. An esterification reaction product with an acid component of

  Polyether diols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; block or random polymer diols such as polyethylene polypropoxy block polymer diol; and bisphenol A ethylene oxide adduct diol and bisphenol A propylene And diols of bisphenol A alkylene oxide adducts such as oxide adducts.

  These diols may be used alone or in combination of two or more.

  Non-yellowing organic diisocyanates include hexamethylene diisocyanate, lysine methyl ester diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate and other aliphatic diisocyanates, isophorone diisocyanate (hereinafter referred to as “IPDI”), 4, 4'-methylenebis (cyclohexyl isocyanate) (hereinafter referred to as “H12MDI”) and alicyclic diisocyanates such as ω, ω′-diisocyanate dimethylcyclohexane and the like.

  These organic diisocyanate compounds may be used alone or in combination of two or more.

  Among the above-mentioned compounds, when light resistance (weather resistance) is required for the cured product, IPDI and H12MDI are preferable.

As the hydroxyl group-containing (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxy Examples include octyl (meth) acrylate, pentaerythritol tri, di or mono (meth) acrylate, and hydroxyalkyl (meth) acrylate such as trimethylolpropane di or mono (meth) acrylate.
Among the above-mentioned compounds, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate are preferable in that the flexibility of the pressure-sensitive adhesive sheet is excellent.

(A) A component may be manufactured according to the conventional method.
In the case of producing compound A1, in the presence of a urethanization catalyst such as dibutyltin dilaurate, the diol and non-yellowing organic diisocyanate to be used are heated and stirred for addition reaction, and further, hydroxyalkyl (meth) acrylate is added, heated and stirred for addition. In the case of producing compound A2, in the presence of the same catalyst as described above, a diol, a non-yellowing organic diisocyanate and a hydroxyalkyl (meth) acrylate are simultaneously added and heated and stirred. Is mentioned.

  (A) A component may use only 1 type or may use 2 or more types together.

2. Component (B) The component (B) is a compound having one (meth) acryloyl group. In the present invention, by including the component (B), the coating property of the composition and the mechanical strength of the cured product can be balanced.

  As the component (B), isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclohexyl (meth) acrylate, trimethylcyclohexyl (meth) acrylate, 1 -Adamantyl (meth) acrylate, 2-ethylhexyl carbitol acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t- Butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, tetrahydrofurf (Meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, benzyl (meth) acrylate, allyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, phenoxyethyl (Meth) acrylate, о-phenylphenol EO modified (n = 1 to 4) (meth) acrylate, p-cumylphenol EO modified (n = 1 to 4) (meth) acrylate, phenyl (meth) acrylate, о− Phenylphenyl (meth) acrylate, p-cumylphenyl (meth) acrylate, (meth) acryloylmorpholine, N-vinylformamide, N- (meth) acryloyloxyethyl hexahydrophthalimide and N- (meth) acryloyloxye Le tetrahydrophthalimide, and the like.

  As the component (B), only one kind of the aforementioned compounds may be used, or two or more kinds may be used in combination.

  As the component (B), a hydrophobic (meth) acrylate is preferable among the above-described compounds in terms of excellent water resistance. As the hydrophobic (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate and 2-ethylhexyl carbitol acrylate are preferable.

3. In the present invention , an electron beam curable composition for forming a pressure sensitive adhesive sheet containing the component (A) and the component (B) as essential components is used .
As a manufacturing method of a composition, what is necessary is just to follow a conventional method, using (A) component and (B) component, using other components further as needed, and obtaining these by stirring and mixing. it can.
When stirring and mixing each component, it can be heated or heated as necessary.

The proportion of the component (A) and the component (B) may be appropriately set according to the purpose. However, the amount of the component (A) is 20 to 95% by weight based on the total amount of the component (A) and the component (B). The component (B) is preferably 5 to 80% by weight, more preferably (A) 30 to 90% by weight and (B) component 10 to 70% by weight.
By making the ratio of the component (A) 20% by weight or more, the cured product obtained can be excellent in flexibility, and by making it 95% by weight or less, the viscosity of the composition is lowered, It can be excellent in coatability.

As a glass transition temperature of the hardened | cured material of the composition of this invention, it is preferable that it is -20 degrees C or less, and it is more preferable that it is -30 degrees C or less. When the glass transition temperature of the copolymer exceeds −20 ° C., tack as an adhesive tends to be insufficient.
In the present invention, the glass transition temperature means a tan δmax temperature obtained by measuring dynamic viscoelasticity in a shear mode according to JIS K7244-4.

The compositions of the present invention is an electron beam-curable composition, and does not include a photoinitiator. By not containing a photopolymerization initiator, the obtained cured product can be excellent in heat resistance and light resistance.

The composition of the present invention essentially comprises the component (A) and the component (B), but various components can be blended depending on the purpose.
Specifically, a plasticizer [hereinafter referred to as component (C)], an ethylenically unsaturated compound other than components (A) and (B) [hereinafter referred to as component (D)], an organic solvent [hereinafter referred to as (E) A component, a polymerization inhibitor or / and an antioxidant, and a light resistance improver.
Hereinafter, these components will be described.

● Component (C) The component (C) is a plasticizer.
(C) component is a component mix | blended as needed for the purpose of adjusting the adhesiveness of hardened | cured material.

  Plasticizers include phthalates such as dimethyl phthalate, diethyl phthalate, and dioctyl phthalate; aliphatic dibases such as dimethyl adipate, dibutyl adipate, dioctyl adipate, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, and diethyl succinate Acid esters and aliphatic polybasic acid esters such as tributyl acetylcitrate; orthophosphate esters such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate and tricresyl phosphate; glyceryl triacetate and 2-ethylhexyl acetate Acetates; Phosphites such as triphenyl phosphite and dibutyl hydrogen phosphite; Natural resins such as rosin resins and terpene resins; Derivatives; and polyesters, acrylic polymers, polyethers and inert compounds such as petroleum resins.

  As the component (C), only one kind of the aforementioned compounds may be used, or two or more kinds may be used in combination.

  The content ratio of component (C) may be appropriately set according to the purpose, but is preferably 1 to 90% by weight, more preferably 5 to 80% by weight in the composition.

● Component (D) The component (D) is an ethylenically unsaturated compound other than the components (A) and (B).
(D) A component is a component mix | blended as needed for the purpose of reducing the viscosity of the whole composition and adjusting the other physical properties.

  Specific examples of the component (D) include (meth) acrylates other than the components (A) and (B) [hereinafter referred to as “other (meth) acrylates”].

  Examples of other (meth) acrylates include compounds having two or more (meth) acryloyl groups (hereinafter referred to as “polyfunctional (meth) acrylates”).

Specific examples of the polyfunctional (meth) acrylate include bisphenol A EO-modified (n = 1 to 2) di (meth) acrylate, bisphenol A di (meth) acrylate, ethylene glycol di (meth) acrylate, and diethylene glycol di (meth). Acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol (n = 5-14) di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) Acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol (n = 5-14) di (meth) acrylate, 1,3-butylene glycol Di (meth) acrylate, 1,4-butanediol di (meth) acrylate, polybutylene glycol (n = 3 to 16) di (meth) acrylate, poly (1-methylbutylene glycol) (n = 5 to 20) di (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, Maleic anhydride adduct and 2-hydroxy of dicyclopentanediol di (meth) acrylate, bifunctional (meth) acrylate of tricyclodecane dimethylol di (meth) acrylate, polyisoprene (meth) acrylate and polyisoprene polymer Ethyl (meth) acrylate And the like of the ester product is.
In the above, EO modification means ethylene oxide modification, and n means the number of repeating alkylene oxide units.

  As the component (D), only one of the aforementioned compounds may be used, or two or more may be used in combination.

  The ratio of the component (D) may be appropriately set according to the purpose, and may be an amount that does not reduce the flexibility of the resulting cured product, but the total amount of the component (A) and the component (B) is 100 weights. The amount is preferably 1 to 100% by weight, more preferably 1 to 80% by weight based on the part.

● (E) Component The composition of the present invention preferably contains an organic solvent as the component (E) for the purpose of improving the coating property to the substrate.

Specific examples of the component (E) include hydrocarbon solvents such as n-hexane, benzene, toluene, xylene, ethylbenzene, and cyclohexane;
Methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol, 2-butoxy Ethanol, 2-isopentyloxyethanol, 2-hexyloxyethanol, 2-phenoxyethanol, 2-benzyloxyethanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, 1 Alcohol-based solvents such as methoxy-2-propanol and 1-ethoxy-2-propanol;
Ether solvents such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, bis (2-methoxyethyl) ether, bis (2-ethoxyethyl) ether and bis (2-butoxyethyl) ether;
Ketone solvents such as acetone, methyl ethyl ketone, methyl-n-propyl ketone, diethyl ketone, butyl methyl ketone, methyl isobutyl ketone, methyl pentyl ketone, di-n-propyl ketone, diisobutyl ketone, phorone, isophorone, cyclohexanone and methylcyclohexanone Can be mentioned.

  As the component (E), one or more of the aforementioned compounds can be used.

  The proportion of the component (E) may be appropriately set, but is preferably 10 to 90% by weight, more preferably 40 to 80% by weight in the composition.

● Polymerization inhibitor or / and antioxidant It is preferable to add a polymerization inhibitor or / and an antioxidant to the composition of the present invention, which can improve the storage stability of the composition of the present invention. .
As the polymerization inhibitor, hydroquinone, hydroquinone monomethyl ether, 2,6-di-tert-butyl-4-methylphenol, and various phenolic antioxidants are preferable. A secondary antioxidant or the like can also be added.
The total blending ratio of these polymerization inhibitors or / and antioxidants is preferably 0.001 to 3% by weight, more preferably 100 parts by weight of the total amount of component (A) and component (B). Is 0.01 to 0.5% by weight.

-Light resistance improver You may add light resistance improvers, such as a ultraviolet absorber and a light stabilizer, to the composition of this invention.
Examples of the ultraviolet absorber include 2- (2′-hydroxy-5-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2- (2 Benzotriazole compounds such as'-hydroxy-3'-t-butyl-5'-methylphenyl)benzotriazole;
Triazine compounds such as 2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-iso-octyloxyphenyl) -s-triazine;
2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2, 4, 4 ' -Trihydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3', 4,4'-tetrahydroxybenzophenone, or 2,2 Examples include benzophenone compounds such as'-dihydroxy-4,4'-dimethoxybenzophenone.
Examples of the light stabilizer include N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) -N, N′-diformylhexamethylenediamine, bis (1,2,6,6). -) Pentamethyl-4-piperidyl) -2- (3,5-ditertiarybutyl-4-hydroxybenzyl) -2-n-butylmalonate, bis (1,2,2,6,6-pentamethyl-4- Low molecular weight hindered amine compounds such as piperidinyl) sebacate; N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) -N, N′-diformylhexamethylenediamine, bis (1,2, And hindered amine light stabilizers such as high molecular weight hindered amine compounds such as 2,6,6-pentamethyl-4-piperidinyl) sebacate.
The blending ratio of the light fastness improver is preferably 0 to 5% by weight, more preferably 0 to 1% by weight, based on 100 parts by weight of the total amount of the component (A) and the component (B).

4). Method of Use The composition of the present invention can employ various methods of use depending on the purpose of producing the pressure-sensitive adhesive sheet.
Specifically, a method of applying a composition to a substrate and irradiating it with an electron beam and curing it, and a method of irradiating and curing an electron beam after bonding to another substrate are exemplified.

  As a substrate, in addition to a release-treated sheet or film (hereinafter referred to as “release material”), a surface-treated sheet or film such as a hard coat treatment or a material intended for adhesion (hereinafter referred to as “adhesion”) Body ”).

  Examples of the release material include a silicone-treated polyethylene terephthalate film and a surface untreated OPP film (polypropylene).

Examples of the material of the adherend include metals such as polymers, glass, ceramics, steel plates and aluminum, vapor deposition films of metals and metal oxides, and silicon.
Polymers include cellophane, polyester such as polyethylene terephthalate and polyethylene naphthalate, polyamide, polyimide, polycarbonate, urea / melamine resin, epoxy resin, polyurethane, polylactic acid, polyethylene, polypropylene, cycloolefin polymer, acrylic resin, methacrylic resin, poly Examples include vinyl chloride, polystyrene, polyvinyl acetate, polyvinyl alcohol, triacetyl cellulose, hydroxypropyl cellulose, polyethersulfone, copolymers of the above polymers, liquid crystal polymers, and fluororesins. These polymers are preferably in the form of a film or a sheet.

  As a coating method, it may be appropriately set depending on the purpose, and it is applied with a conventionally known bar coater, applicator, doctor blade, knife coater, comma coater, reverse roll coater, die coater, gravure coater, micro gravure coater, etc. The method of doing is mentioned.

What is necessary is just to set suitably irradiation conditions, such as a dose in electron beam irradiation, according to the composition to be used, a base material, the objective, etc.
The absorbed dose of the electron beam is preferably 1 to 100 kGy, more preferably 10 to 80 kGy.
The acceleration voltage of the electron beam may be appropriately set in the range of 80 to 300 kV according to the film thickness of the composition, and 200 kV is preferable when the film thickness is 100 μm.
The oxygen concentration in the electron beam irradiation atmosphere is preferably 500 ppm or less, more preferably 300 ppm or less.

5. Adhesive Sheet The composition of the present invention can be preferably used for the production of an adhesive sheet.
Hereinafter, the adhesive sheet will be described.
Hereinafter, a part of the description will be given with reference to FIGS. 1 and 2.

5-1. Production method of pressure- sensitive adhesive sheet The production method of the pressure-sensitive adhesive sheet may be a conventional method. For example, the composition can be produced by applying the composition to a substrate and then irradiating it with an electron beam.

FIG. 1 shows an example of a preferable method for producing a pressure-sensitive adhesive sheet composed of a release material / cured product.
In FIG. 1, (1) means a release material.
When the composition is a solventless type (FIG. 1: F1), the composition is applied to a release material [FIG. 1: (1)]. When the composition contains an organic solvent or the like (FIG. 1: F2), the composition is applied to a release material [FIG. 1: (1)] and then dried to evaporate the organic solvent or the like (FIG. 1: 1). -1).
By irradiating an electron beam to the sheet in which the composition layer (2) is formed on the release material, a pressure-sensitive adhesive sheet composed of the release material / cured product is obtained. The electron beam is usually irradiated from the composition layer side, but can also be irradiated from the release material side.
In the above, if an adherend is used as the substrate (1), an adhesive sheet composed of the adherend / cured product can be produced.

The coating amount of the composition of the present invention may be appropriately selected depending on the application to be used, but is applied so that the film thickness after drying the organic solvent or the like is 50 to 200 μm.

When the composition contains an organic solvent or the like, it is dried after coating to evaporate the organic solvent or the like.
What is necessary is just to set drying conditions suitably according to the organic solvent etc. to be used, and the method of heating to the temperature of 40-150 degreeC etc. are mentioned.

  What is necessary is just to set suitably irradiation conditions, such as a dose in electron beam irradiation, according to the composition to be used, a base material, the objective, etc.

FIG. 2 shows an example of a preferable method for producing a pressure-sensitive adhesive sheet composed of a release material / cured product / release material.
In FIG. 2, (1), (3), and (4) mean release materials.
When the composition is a solventless type (FIG. 2: F1), the composition is applied to a release material [FIG. 2: (1)]. When the composition contains an organic solvent or the like (FIG. 2: F2), the composition is applied to a release material [FIG. 2: (1)] and then dried to evaporate the organic solvent (FIG. 2: 2). -1). In the composition layer (2), a release material (3) is laminated and then irradiated with an electron beam, or after being irradiated with an electron beam, a release material, a cured product and a release material are formed in this order. An adhesive sheet is obtained.

5-2. Application of pressure-sensitive adhesive sheet The pressure-sensitive adhesive sheet formed from the composition of the present invention can be used for various applications.
As a kind of adhesive sheet, it can be used for an adhesive label, an adhesive tape, a special adhesive film, and the like.
Specific examples of adhesive labels include trademark labels, quality labeling labels, content labeling labels, returnable labels, nameplates, etc. for product display, weighing labels, hand labels, price tags, price tags, price labels, instruction labels, inspections Certificate label, warranty label, tamper-proof label, distribution diagram label, scale plate label, PL law warning label, etc. for explanation and warranty, sticker (for window, vehicle, shop front, etc.), mark / decoration label, stamp , Seals, emblems, posters, multi-layer labels, etc. for promotion / promotion, form labels, computer labels, POS labels, process / inventory management labels, etc., double-sided / single-sided tag labels, mailing labels, home delivery slips For labels such as labels and addresses, seals for seals, seals for cap seals, etc., guide sign labels, traffic sign labels, facility sign labels, etc. For interior / signposting, toiletry-related labels, home appliance labels, OA equipment labels, etc., other index labels (for stationery, video cassettes, flexible disks, etc.), color sample labels, toys (seal) And for teaching materials.

  Adhesive tape includes nameplate tape, metal building material tape, automotive tape, surface protection, semiconductor manufacturing process tape, electronic component transport tape, protection / masking tape, fixing / adhesion tape, electrical insulation For general electrical masking such as coating masking tape, curing masking tape, etc., for electrical and electronic equipment such as tape for tape, binding / repair tape, conductive tape, display / sealing on EPS (expanded polystyrene beads fused product) cases General bundling and fixing applications such as sealing and packaging for cardboard packaging tape, office use, other automotive decoration tape, photoengraving tape, splicing tape, double-sided tape, cellophane tape, OPP tape, etc. Can be mentioned.

  Special adhesive films include outdoor advertising films, outdoor stripes for automobiles, marking films, etc., posters, interior films, general wall coverings such as interior materials, elevator interior films, counter decoration films, furniture decoration films, vehicle interior films , Interior decoration such as vending machine decoration film, cash corner decoration film, table decoration film, etc., for short-term decoration such as wind display film, sticker, marking film, etc., for interior lighting signage such as outdoor durable film, etc. For films, safety reflective films (for automobiles, shoes, helmets, etc.), for automobiles, etc. as window films to be applied while wet with water or soapy water, other prisms, hologram films, daylight films and luminescent films Etc. The.

  The pressure-sensitive adhesive sheet of the present invention is excellent in the balance between the transparency of a cured product and the degree of yellowing after a light resistance test, and takes advantage of the characteristics of reworkability and step following capability, thereby providing a liquid crystal display device, an organic EL display device, and a touch panel. It can be preferably used for an air gap filler of a display device such as a type image display device.

A specific configuration of a display device using the composition of the present invention as an air gap filler will be described. A display device in which the protective panel and the image display device are integrated through the cured product of the composition of the present invention, and a touch panel module and the image display device are integrated through the cured product of the composition of the present invention. Examples include a touch panel display device.
An example of using a pressure-sensitive adhesive sheet composed of the above-described release material / cured product / release material will be described as a method for manufacturing a display device. First, peel off the release material on one side of the adhesive sheet, attach the adhesive surface to the protective panel or image display device, then peel off the release material on the other side, and attach the adhesive surface to the image display device or protective panel respectively. And the like. A touch panel display device can also be manufactured according to this method.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following, “parts” means parts by weight.

○ Production Example 1 [Production of component (A)]
In a 500 mL reaction vessel equipped with a stirrer, 200 g (0.118 mol) of a polydiene diol having a number average molecular weight of 1,500 (GI Soda, Nippon Soda Co., Ltd., hydrogenated polybutadiene both-end diol) was used as a catalyst. 270 mg of dibutyltin dilaurate (1,000 ppm in the reaction solution) and 270 mg of 2,6-di-t-butyl-4-methylphenol were added as a polymerization inhibitor, and these were added under an atmosphere of nitrogen containing 5% by volume of oxygen. While stirring, the liquid temperature was increased to 70 ° C. To the reaction solution, 39.6 g (0.236 mol) of hexamethylene diisocyanate was added all at once and reacted for 2 hours.
Thereafter, 27.4 g (0.236 mol) of 2-hydroxyethyl acrylate was added and reacted for 3 hours. The spectrum was measured with an infrared absorption spectrum apparatus (FT-IR Spectrum 100 manufactured by Perkin Elmer). After confirming consumption, urethane acrylate (hereinafter referred to as “UA-1”) was obtained.
The weight average molecular weight of UA-1 in terms of polystyrene (hereinafter referred to as “Mw”) was measured by gel permeation chromatography (solvent: tetrahydrofuran, column: HSPgel HR MB-L manufactured by Waters), and was 9,000.

(1) Example (Production of composition)
The components shown in Table 1 below were charged in a stainless steel container at the ratio shown in Table 1, and stirred with a magnetic stirrer while heating to obtain a composition.

The abbreviations in Table 1 mean the following.
M120: 2-ethylhexyl carbitol acrylate, Aronix M-120 manufactured by Toagosei Co., Ltd.
-IBXA: Isobornyl acrylate, IBXA manufactured by Osaka Organic Chemical Industry Co., Ltd.
ATBC: tributyl acetyl citrate TEAI1000: polybutadiene yellowing urethane acrylate (organic diisocyanate: tolylene-2,6-diisocyanate), TEAI-1000 manufactured by Nippon Soda Co., Ltd.
Dc1173: 2-hydroxy-2-methyl-1-phenylpropan-1-one, DAROCUR-1173 manufactured by BASF Japan

(2) Examples 4 to 6 and Comparative Examples 5 to 6 (Manufacture of pressure-sensitive adhesive sheets by electron beam curing)
It was obtained in Examples 1 to 3 and Comparative Examples 1 and 2 to a release film “Therapyl BX8” (silicone-treated polyethylene terephthalate film, thickness 38 μm) manufactured by Toray Film Processing Co., Ltd. having a width of 300 mm and a length of 300 mm. The composition was heated and coated with an applicator so that the film thickness was 100 μm.
Then, after laminating “Therapy BKE” (silicone-treated polyethylene terephthalate film, thickness 38 μm) having a width of 300 mm and a length of 300 mm on the composition layer, an acceleration voltage of 200 kV was applied by an electron beam irradiation apparatus manufactured by NHV Corporation. The pressure sensitive adhesive sheet was obtained by performing electron beam irradiation under the conditions of a dose of 50 kGy (adjusted by the beam current and conveying speed) and an oxygen concentration of 300 ppm or less.
After curing, it was used for evaluation of total light transmittance, haze, light resistance test, rework property and step following property described later.
The total light transmittance, haze, and light resistance test were evaluated without peeling the silicone-treated polyethylene terephthalate film, and the rework property and the step following ability were evaluated by peeling the silicone-treated polyethylene terephthalate film.

(3) Comparative Examples 7 to 8 (Manufacture of pressure-sensitive adhesive sheets by ultraviolet curing)
The UV-curable composition obtained in Comparative Examples 3 and 4 was heated on a 300 mm wide x 300 mm long therapy BX8 and coated with an applicator so that the film thickness was 100 μm.
Then, after laminating 300 mm width x 300 mm length therapy BKE on the composition layer, a conveyor type ultraviolet irradiation device (high pressure mercury lamp, lamp height 12 cm, 365 nm irradiation intensity 400 mW / cm, manufactured by Eye Graphics Co., Ltd.) ² (measured value of UV POWER PUCK manufactured by Fusion UV Systems Japan Co., Ltd.) was adjusted to carry out ultraviolet irradiation with an integrated light amount of 1,000 mJ / cm ² to obtain an ultraviolet curable adhesive sheet.
After curing, it was used in the evaluation described later in the same manner as the electron beam cured pressure-sensitive adhesive sheet.

[Total light transmittance and haze]
About the adhesive sheet obtained by the Example and the comparative example, the total light transmittance and haze were measured using the haze meter [Nippon Denshoku Industries Co., Ltd. NDH2000]. The results are shown in Table 2.
In addition, the measured value is a value including two sheets of therapy BX8 and therapy BKE, and two sheets of therapy BX8 and therapy BKE were measured as blanks.

(Light resistance test)
Initial YI (Yellowing Index) of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples and YI change after being left in an ultraviolet fade meter (UV Long Life Fade Meter FAL-5H type manufactured by Suga Test Instruments Co., Ltd.) for 500 hours The light resistance of the adhesive sheet was evaluated by measuring (ΔYI). The results are shown in Table 2.
In addition, the YI value was measured using a high-speed integrating sphere type spectral transmittance measuring device [SPECTROTOPOMETER DOT-3C manufactured by Murakami Color Research Laboratory Co., Ltd.].
In addition, the measured value is a value including two sheets of therapy BX8 and therapy BKE, and two sheets of therapy BX8 and therapy BKE were measured as blanks.

[Reworkability]
After sticking the adhesive sheets obtained in Examples and Comparative Examples to the space between the 3-inch liquid crystal cell and the protective panel made of polymethylmethacrylate or the capacitive touch panel module, the adhesive sheet was peeled off, The state was confirmed visually. The adhesive sheet that did not break down and could be peeled off was rated as ◯, and the one that even part of the material was broken was marked as x.

[Step following capability]
The pressure-sensitive adhesive sheets obtained in the examples and comparative examples were pasted on the entire surface of the step formed by performing linear black printing having a length of 50 mm, a width of 5 mm, and a thickness of 20 μm on a smooth acrylic plate. At that time, the presence or absence of air pockets at the edge of the black print edge was confirmed with an optical microscope (magnification 100 times). If there was no air accumulation and bonding was possible, it was rated as ○, and otherwise it was marked as ×.

Examples 4 to 6 are pressure-sensitive adhesive sheets obtained by irradiating the compositions of Examples 1 to 3 which are the compositions of the present invention with an electron beam. The yellowing degree after the light resistance test is small, the reworkability and Excellent step following capability.
On the other hand, the comparative example 5 is an adhesive sheet obtained by irradiating the composition of the comparative example 1 which does not contain (B) component with an electron beam, and was inferior to rework property and level | step difference followability.
Comparative Example 6 was a pressure-sensitive adhesive sheet obtained by irradiating the composition of Comparative Example 2 containing urethane acrylate produced from a yellowed organic diisocyanate with an electron beam, and the degree of yellowing after the light resistance test was large.
Comparative Example 7 is a pressure-sensitive adhesive sheet obtained by irradiating the composition of Comparative Example 3 containing a photoinitiator polymer with ultraviolet rays, although it contains components (A) and (B). Comparative Example 8 is Comparative Example 2 It was the adhesive sheet obtained by irradiating the composition of the comparative example 4 which is a composition which contains a photoinitiator further in this composition with ultraviolet rays, and all had the large yellowing degree after a light resistance test.

Pressure-sensitive adhesive sheet of the present invention, a liquid crystal display device is preferably used to form the air gap filler of the organic EL display device and a touch panel-type image display apparatus.

FIG. 1 shows an example of production of a pressure-sensitive adhesive sheet using the composition of the present invention. FIG. 2 shows an example of the production of an adhesive sheet using the composition of the present invention.

Claims (12)

A film or sheet-like substrate (hereinafter collectively referred to as “sheet-like substrate”), an electron beam irradiation cured product of the following composition, and a sheet-like substrate are formed in this order,
The thickness of the electron beam irradiation cured product is 50 to 200 μm.
An adhesive film or sheet for an air gap filler of a display device .

◆ Includes urethane (meth) acrylate (A) which is a reaction product of hydrogenated polybutadienediol, non-yellowing organic diisocyanate and hydroxyl group-containing (meth) acrylate, and compound (B) having one (meth) acryloyl group ,
An electron beam curable composition for forming an adhesive film or sheet that does not contain a photopolymerization initiator. The pressure-sensitive adhesive film or sheet for an air gap filler of a display device according to claim 1, wherein the component (B) is a hydrophobic (meth) acrylate. 3. The display device according to claim 1, comprising 20 to 95% by weight of (A) component and 5 to 80% by weight of (B) component, based on the total amount of (A) component and (B) component . Adhesive film or sheet for air gap filler . The pressure-sensitive adhesive film or sheet for an air gap filler of a display device according to any one of claims 1 to 3, wherein the composition further contains a plasticizer. The pressure-sensitive adhesive film or sheet for an air gap filler of a display device according to any one of claims 1 to 4, wherein any one or both of the sheet-like base materials are release-treated base materials. The following composition is applied to a sheet-like base material with a film thickness of 50 to 200 μm, and another sheet-like base material is bonded to the coating surface of the composition, and then electrons are applied from either side of the sheet-like base material. The manufacturing method of the adhesive film or sheet | seat for air gap fillers of the display apparatus which irradiates a line.

◆ Includes urethane (meth) acrylate (A) which is a reaction product of hydrogenated polybutadienediol, non-yellowing organic diisocyanate and hydroxyl group-containing (meth) acrylate, and compound (B) having one (meth) acryloyl group ,
An electron beam curable composition for forming an adhesive film or sheet that does not contain a photopolymerization initiator. The method for producing an adhesive film or sheet for an air gap filler of a display device according to claim 6 , wherein the component (B) is a hydrophobic (meth) acrylate. The display device according to claim 6 or 7 , comprising 20 to 95% by weight of component (A) and 5 to 80% by weight of component (B) based on the total amount of component (A) and component (B) . The manufacturing method of the adhesive film or sheet | seat for air gap fillers . The method for producing an adhesive film or sheet for an air gap filler of a display device according to any one of claims 6 to 8 , wherein the composition further contains a plasticizer. Either one of the sheet-like substrate, or display the manufacture of pressure-sensitive adhesive film or sheet for an air gap filler apparatus according to any one of both is releasing treated substrate according to claim 6 to claim 9 Method. A display in which the protective panel and the image display device are integrated through an electron beam irradiation cured product of the pressure-sensitive adhesive film or sheet of the display device according to any one of claims 1 to 5. apparatus. A touch panel in which a touch panel module and an image display device are integrated via an electron beam irradiation cured product of an adhesive film or sheet for an air gap filler of a display device according to any one of claims 1 to 5. Type display device.

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