JP2007009076A - Adhesive composition and adhesive sheet member using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition excellent in heat resistance and light resistance, good in visible light transparency, and having sufficient absorbing function(NIR cutting function) for near-infrared rays(NIR) of 850-1,100 nm wavelengths. <P>SOLUTION: The adhesive composition comprises (A-1) 100 pts.mass of a (meth)acrylic ester copolymer having one or more functional groups selected from hydroxy, glycidyl, amido and N-substituted amido groups but containing no carboxy group and having a mass-average molecular weight of 400,000-2,500,000 and (B) 0.08-2.0 pts.mass of golden nanorods. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive composition having a selective absorption function with respect to visible light and near-infrared light, and a pressure-sensitive adhesive sheet member using the same.

  In recent years, the progress of optoelectronic components and equipment has been remarkable, and among them, the demand for displays for displaying images has been increasing for computer monitors and the like in addition to conventional television devices. In particular, the market demand for larger and thinner displays is increasing. Recently, a plasma display panel (PDP) has attracted attention as a display that can be made large and thin. In principle, the PDP emits strong near infrared rays to the outside of the device. This near infrared ray causes malfunction of a cordless telephone or an infrared remote controller.

  Therefore, a near infrared (NIR) cut film is used for the plasma display panel in order to block near infrared rays. For example, a plasma display panel using a near-infrared reflective layer in which a thin film of a metal oxide such as an oxide of indium and tin (ITO) or the like and a thin film made of an alloy of gold or silver is used as a near-infrared cut film is known. (For example, Patent Document 1). This NIR cut film is attached to the panel via an adhesive. In addition, the PDP usually requires a functional layer such as an antireflection film in addition to the NIR cut film, and these are also attached via an adhesive. Therefore, many processes are required.

  In order to simplify the above process, a plasma display panel is known in which an NIR absorbing compound such as a cyanine dye is contained in an adhesive layer and an antireflection film is pasted through the adhesive layer (for example, Patent Documents). 2). However, the coloring matter is inferior in heat resistance, light resistance and the like, and when added to an adhesive, there is a problem that the NIR cut performance is lost due to deterioration in a short time.

  Further, metal nanorods such as gold nanorods are known as substances that absorb in the near infrared region. When the metal fine particles are irradiated with light, a resonance absorption phenomenon called plasmon absorption occurs. When the shape of the metal fine particles is made into a rod shape, it has different plasmon resonance frequencies in the short axis direction and the long axis direction, in addition to absorption in the visible range due to the short axis, in the near infrared region due to the long axis. Has absorption. Plasma display panels using such a coating composition containing metal nanorods as a near-infrared cut film are known (for example, Patent Documents 3 and 4). This composition is a paint and does not have tackiness.

JP 2002-323860 A JP 2002-260539 A JP 2003-313506 A JP 2003-315531 A

  An object of the present invention is to provide a pressure-sensitive adhesive composition having excellent heat resistance and light resistance, good visible light transmittance and a sufficient absorption function (NIR cut function) for near infrared light. It is. The pressure-sensitive adhesive composition of the present invention has been achieved by combining a specific resin and a gold nanorod.

That is, the present invention
(1) (A-1) It has one or more functional groups selected from a hydroxyl group, a glycidyl group, an amide group and an N-substituted amide group, does not contain a carboxyl group, and has a mass average molecular weight of 400,000 to 250 A pressure-sensitive adhesive composition comprising 100 parts by mass of (meth) acrylic acid ester copolymer which is 10,000, and (B) 0.08 to 2.0 parts by mass of gold nanorods;
(2) (A-1) It has one or more functional groups selected from a hydroxyl group, a glycidyl group, an amide group and an N-substituted amide group, does not contain a carboxyl group, and has a mass average molecular weight of 400,000 to 250 A (meth) acrylic acid ester copolymer that is 10,000 and (A-2) a (meth) acrylic acid ester (co) polymer that has a weight average molecular weight of 1,000 to 50,000 (A-1) / (A-2) A pressure-sensitive adhesive composition containing 100 parts by mass of a mixture containing at a mass ratio of 0.5 to 20 and (B) 0.08 to 2.0 parts by mass of gold nanorods;
(3) The pressure-sensitive adhesive composition according to the above (1) or (2), wherein the glass transition temperature of the component (A-1) is 0 ° C. or lower;
(4) The pressure-sensitive adhesive composition according to the above (2) or (3), wherein the glass transition temperature of the component (A-2) is -80 to 230 ° C;
(5) The pressure-sensitive adhesive composition according to any one of (1) to (4) above, wherein the particle size of the gold nanorod is 100 nm or less;
(6) The pressure-sensitive adhesive composition according to any one of (1) to (5) above, wherein an average visible light transmittance at a wavelength of 380 to 780 nm is 30 to 90%;
(7) The pressure-sensitive adhesive composition according to any one of (1) to (6) above, wherein the minimum light transmittance in a wavelength region of 850 to 1100 nm is 10% or less;

(8) A pressure-sensitive adhesive sheet member having a base material layer and coated with the pressure-sensitive adhesive composition according to any one of the above (1) to (7) on at least one surface thereof;
(9) The pressure-sensitive adhesive sheet member according to (8), which is used for optical applications; and (10) The pressure-sensitive adhesive sheet according to (9), which is used for a plasma display panel. Providing a member.

  The pressure-sensitive adhesive composition of the present invention is excellent in heat resistance and light resistance, has good visible light transmittance at a wavelength of 380 to 780 nm, and has a sufficient absorption function (NIR) for near infrared light at a wavelength of 850 to 1100 nm. Cutting function). Therefore, an adhesive sheet member having NIR cut performance can be obtained by applying this composition to the base material layer. When applied to optical applications, particularly plasma display panels, this pressure-sensitive adhesive sheet member can be provided with a NIR cut function without an extra pressure-sensitive adhesive process, and also has other functional layers such as an antireflection film. It can apply without the adhesion process of.

The pressure-sensitive adhesive composition of the present invention has (A-1) one or more functional groups selected from a hydroxyl group, a glycidyl group, an amide group and an N-substituted amide group, does not contain a carboxyl group, and has a mass average. It contains 100 parts by mass of a (meth) acrylic acid ester copolymer having a molecular weight of 400,000 to 2.5 million, and (B) 0.08 to 2.0 parts by mass of gold nanorods.

Another pressure-sensitive adhesive composition of the present invention has (A-1) one or more functional groups selected from a hydroxyl group, a glycidyl group, an amide group and an N-substituted amide group, does not contain a carboxyl group, and (Meth) acrylic acid ester copolymer having a mass average molecular weight of 400,000 to 2.5 million and (A-2) (meth) acrylic acid ester (co) polymer having a mass average molecular weight of 1,000 to 50,000 And (A-1) / (A-2) = 100 to 20 parts by mass of a mixture, and (B) 0.08 to 2.0 parts by mass of gold nanorods. To do. When component (A-2) is added in addition to component (A-1), the tackiness can be appropriately adjusted while maintaining durability.

Next, each component of the present invention will be described. In the present specification, “(meth) acrylic acid ester” is a term indicating an acrylic acid ester, a methacrylic acid ester, and a mixture of both.

The (meth) acrylic acid ester copolymer of component (A-1) has one or more functional groups selected from a hydroxyl group, a glycidyl group, an amide group, and an N-substituted amide group. A preferred functional group is a hydroxyl group. If there is no functional group, sufficient tackiness cannot be obtained. Moreover, a component (A-1) does not contain a carboxyl group. When the component (A-1) contains a carboxyl group, the gold nanorods of the component (B) are aggregated without being dispersed, and the NIR cut function cannot be obtained.

Component (A-1) may be a copolymer of a (meth) acrylic acid ester having 1 to 20 carbon atoms in the alkyl moiety of the ester moiety and a (meth) acrylic acid monomer having the above functional group. May contain (meth) acrylic acid monomers having other functional groups and other monomers.

Examples of the (meth) acrylic acid ester having 1 to 20 carbon atoms in the alkyl group of the ester moiety include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid. Butyl, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, (meth) acryl Examples include dodecyl acid, myristyl (meth) acrylate, palmityl (meth) acrylate, and stearyl (meth) acrylate. These may be used alone or in combination of two or more.

Examples of the (meth) acrylic acid monomer having a functional group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and (meth) acrylic acid. Monomers containing hydroxyl groups such as 2-hydroxybutyl, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate; (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl ( Amide groups or N-substituted amides such as (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-tert-butylacrylamide, N-octylacrylamide, N-methylol (meth) acrylamide Monomers containing groups (Meth) include monomers having a glycidyl group such as glycidyl acrylate. These may be used alone or in combination of two or more.

Examples of (meth) acrylic acid monomers having other functional groups include amino group (amino) monomers such as aminomethyl (meth) acrylate, dimethylaminomethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and vinylpyridine. , Monomers containing acetoacetyl groups such as acetoacetoxyethyl (meth) acrylate, Monomers containing tertiary amino groups such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide Is mentioned. These may be used alone or in combination of two or more.

Examples of other monomers optionally used include vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; styrene, Styrene monomers such as α-methylstyrene; Diene monomers such as butadiene, isoprene and chloroprene; Nitrile monomers such as acrylonitrile and methacrylonitrile; N, N-dimethylacrylamide, N, N-dimethyl And N, N-dialkyl-substituted acrylamides such as methacrylamide. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer of component (A-1) is not particularly limited as to its copolymerization form, and may be any of random, block, and graft copolymers. Moreover, the (meth) acrylic ester copolymer of component (A-1) may be used alone or in combination of two or more.

The component (A-1) needs to have a mass average molecular weight in the range of 400,000 to 2.5 million. In the present specification, the mass average molecular weight is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method. If the mass average molecular weight is less than 400,000, the adhesiveness and durability (reliability) may be insufficient, and if it exceeds 2.5 million, the viscosity increases and causes poor coatability. The mass average molecular weight of the component (A-1) is preferably 600,000 to 1,800,000, more preferably 800,000 to 1,600,000.

The component (A-1) preferably has a glass transition temperature (Tg) of 0 ° C. or lower, and more preferably in the range of −70 ° C. to 0 ° C. When the glass transition temperature is higher than 0 ° C., tack (adhesiveness) becomes insufficient when used at a low temperature, and the viscosity is not exhibited, which is not preferable. In this specification, the glass transition temperature (Tg) indicates a calculated value or an actual measurement value obtained by a conventional method. The calculated value is the following formula:
(1 / Tg) = (W ₁ / Tg ₁ ) + (W ₂ / Tg ₂ ) +... + (W _n / Tg _n )
Can be used to calculate. In the formula, Tg represents the glass transition temperature (° C.), W ₁ , W ₂ ,..., W _n represent the mass fraction of each monomer in the monomer composition, and Tg ₁ , Tg _2, ····, Tg _n represents a glass transition temperature of the homopolymer of the corresponding monomer (° C.). In addition, what is necessary is just to employ | adopt the numerical value described in publications, such as handbook, for the glass transition temperature of a homopolymer, for example.

  The (meth) acrylic acid ester copolymer of component (A-1) can be produced by various known methods, for example, radicals such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. A polymerization method can be appropriately selected. As the radical polymerization initiator, known ones such as lauroyl peroxide (LPO), benzoyl peroxide (BPO), azobisisobutyronitrile (AIBN) and the like can be used. As the polymerization conditions, for example, in the case of solution polymerization, the reaction temperature is usually 50 to 150 ° C., and the reaction time is usually about 3 to 15 hours. As a solvent used in the polymerization, ethyl acetate, methyl ethyl ketone, toluene, hexane, acetone or the like is used. Moreover, you may use a commercially available (meth) acrylic acid ester copolymer.

  Component (A-2) is a (meth) acrylic acid ester (co) polymer having a mass average molecular weight of 1,000 to 50,000. When the mass average molecular weight is less than 1,000, bleeding out occurs, and when it exceeds 50,000, the compatibility with the component (A-1) is lowered and the coating property is lowered. The mass average molecular weight of the component (A-2) is preferably 1,000 to 40,000, and more preferably 1,000 to 20,000.

  Component (A-2) may or may not contain a functional group, but does not contain a carboxyl group as in component (A-1). As the functional group that can be contained in the component (A-2), as in the component (A-1), a hydroxyl group, a glycidyl group, an amide group, an N-substituted amide group, an amino group, an acetoacetyl group, and a tertiary group are used. An amino group etc. are mentioned. The component (A-2) may be a homopolymer or copolymer of a (meth) acrylic acid ester having 1 to 20 carbon atoms in the alkyl group of the ester moiety, and a (meth) acrylic acid monomer having a functional group May be included. The (meth) acrylic acid ester having 1 to 20 carbon atoms in the alkyl group of the ester moiety and the (meth) acrylic acid monomer having the functional group are the same as those described for the component (A-1). Further, the component (A-2) may contain other monomers as desired in the same manner as described for the component (A-1).

Component (A-2) preferably has a glass transition temperature (Tg) in the range of −80 to 230 ° C., more preferably in the range of −50 to 150 ° C. When the glass transition temperature is lower than −80 ° C., bleeding out occurs, and when it exceeds 230 ° C., the polymerizability deteriorates.

The method for producing the (meth) acrylic acid ester (co) polymer of component (A-2) is the same as that described for component (A-1). Moreover, you may use a commercially available (meth) acrylic acid ester copolymer.

When the component (A-2) is included in the pressure-sensitive adhesive composition of the present invention, the mass ratio (A-1) / (A-2) between the component (A-1) and the component (A-2) is 0.00. It is the range of 5-20, Preferably it is 1-10, More preferably, it is 1-5. When the ratio is less than 0.5, there are too many low mass average molecular weights, which may cause bleed out. By changing the mass ratio within the above range, the adhesiveness can be adjusted as appropriate while maintaining the durability.

Component (B) is a gold nanorod. The gold nanorod can change the absorption peak position in the wavelength range (530 to 1100 nm) from visible light to near infrared light by controlling the aspect ratio (long axis / short axis ratio). The gold nanorods used in the present invention preferably have a particle diameter (major axis) of 100 nm or less, more preferably 80 nm or less, and an aspect ratio (major axis / minor axis ratio) of 1 to 10, more preferably 2-8. By using the gold nanorod having such a shape, an absorption effect of near-infrared light having a wavelength of 850 to 1100 nm due to the long axis can be obtained.

Gold nanorods can be used in the form of a dispersion or paste in an organic solvent such as toluene, methyl isobutyl ketone, or butyl acetate. Gold nanorods are, for example, electrolysis (see Y.-Y. Yu, S.-S. Chang C.-L. Lee, CRC Wang, J. Phys. Chem. B, 101, 6661 (1997)), Seed method (see CJ Murphy, NR Jana, Adv. Mater., 14, 80 (2002)), photochemical method (F. Kim, JH Song, P. Yang, J. Am. Chem. Soc., 124, 14316 (2002)). Or a commercial item can be used. Examples of the commercially available product include Au-050316 (product name) (gold nanorod toluene dispersion) manufactured by Mitsubishi Materials Corporation.

The amount of the component (B) gold nanorod is 0.08 with respect to 100 parts by mass of the component (A-1) or 100 parts by mass of the mixture of the component (A-1) and the component (A-2). -2.0 mass parts, preferably 0.2-1.2 mass parts. If the amount is less than 0.08 parts by mass, sufficient NIR cut performance cannot be obtained. When the amount is more than 2.0 parts by mass, the average visible light transmittance is lowered and the pigment is remarkably colored.

  In the pressure-sensitive adhesive composition of the present invention, in addition to the components (A-1), (A-2) and (B), if desired, conventional pressure-sensitive adhesive compositions can be used as long as the object of the present invention is not impaired. Various known additives used can be added. Examples of such additives include plasticizers, silane coupling agents, ultraviolet absorbers, crosslinking agents, radical scavengers, antioxidants, pigments, dyes, fillers such as organic or inorganic powders, and antistatic agents. And viscosity modifiers.

Examples of the crosslinking agent include isocyanate compounds, epoxy compounds, amine compounds, metal chelate compounds, and aziridine compounds.

Examples of isocyanate compounds include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, and their trimethylolpropane. Examples thereof include adducts with polyols.

Examples of the epoxy compound include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycol glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, Examples include diglycidylamine, N, N, N ′, N′-tetraglycidyl-m-xylenediamine, and 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane.

Examples of the amine compound include hexamethylenediamine, triethyldiamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethyltetramine, isophoronediamine, amino resin, and methylene resin.

Examples of metal chelate compounds include compounds in which polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium are coordinated to acetylacetone or ethyl acetoacetate. It is done.

Examples of aziridine compounds include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxide), N, N′-toluene-2,4-bis (1-aziridinecarboxamide), triethylene Melamine, bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N′-hexamethylene-1,6-bis (1-aziridinecarboxide), trimethylolpropane -Tri-β-aziridinylpropionate and tetramethylolmethane-tri-β-aziridinylpropionate.

Among the above-mentioned various additives, particularly when a silane coupling agent is added to the pressure-sensitive adhesive composition, the adhesion to the adherend (particularly glass) under wet heat conditions is improved, and the substrate and the glass plate interface float or peel off. Is less likely to occur. This silane coupling agent is an organosilicon compound having at least one alkoxysilyl group in the molecule, having good compatibility with the pressure-sensitive adhesive component, and having light transparency, for example, substantially transparent Is preferred.

Examples of such a silane coupling agent include vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, 2- (3,4 -Epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane and the like, and the addition amount thereof is 100 parts by mass of the component (A-1). Or the range of 0.001-10 mass parts is preferable with respect to 100 mass parts of mixtures of the said component (A-1) and (A-2), and the range of 0.005-5 mass parts is especially more preferable.

  In the pressure-sensitive adhesive composition of the present invention, the component (A-1) or a mixture of the components (A-1) and (A-2) is blended with the component (B) at a desired mass ratio, and an additive is optionally added. In addition, it can be produced by mixing.

The pressure-sensitive adhesive composition of the present invention thus obtained has a specific absorption effect for visible light and near infrared light. Preferably, the pressure-sensitive adhesive composition of the present invention has an average visible light transmittance of 30 to 90% in the wavelength region of 380 to 780 nm and a minimum light transmittance of 10% or less in the wavelength region of 850 to 1100 nm.

The material of the adherend to which the pressure-sensitive adhesive composition of the present invention adheres is not particularly limited, but usually, glass, acrylic plate, PET film, triacetyl cellulose (TAC), which is a material constituting the screen of a display device or the like. ), Polycarbonate (PC) and the like.

Next, the adhesive sheet member of the present invention will be described.
The pressure-sensitive adhesive sheet member of the present invention has a base material layer, and the pressure-sensitive adhesive composition of the present invention is coated on at least one surface thereof.

That is, the pressure-sensitive adhesive sheet member of the present invention includes a base material layer and a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition of the present invention applied to at least one surface thereof.

Examples of the base material include paper base materials such as glassine paper, coated paper, cast coated paper, laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials, or polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate. Polyester films such as polypropylene film, polypropylene film such as polypropylene and polymethylpentene, plastic films such as polycarbonate film and cellulose acetate film, and laminated sheets containing these films, which are appropriately selected depending on the application of the adhesive sheet member.

The base material layer can be used as a member (that is, a release sheet) for transferring the adhesive layer to the adherend, and can also be used as a member for being stuck to a desired adherend. it can. When used in the former application, a release agent such as a silicone resin is usually applied to the substrate.

When using the said base material layer as a peeling sheet, although there is no restriction | limiting in particular as thickness of a base material layer, Usually, it is about 20-150 micrometers. When used as a member to be adhered to a desired adherend, the type and thickness of the base material layer are appropriately selected according to the application. In this case, a normal release sheet can be provided on the pressure-sensitive adhesive layer as desired.

The thickness of the pressure-sensitive adhesive layer is preferably about 5 to 100 μm, particularly preferably in the range of 10 to 60 μm.

The method for forming the pressure-sensitive adhesive layer is not particularly limited, and the pressure-sensitive adhesive composition (solution) of the present invention is applied to the base material layer by a commonly used coating method such as transfer printing, knife coater, roll coater, gravure coater. Examples thereof include a method of applying to one side and heating and drying with infrared rays, hot air, steam, and the like, and a method of transferring with a release sheet provided with an adhesive layer.

Since the pressure-sensitive adhesive sheet member thus obtained has a pressure-sensitive adhesive layer having a specific absorption effect with respect to visible light and near-infrared light, it has sufficient NIR cut performance. Therefore, when this is applied to an optical application, particularly a plasma display panel, it can be provided with a NIR cut function without an extra adhesion step, and other functional layers such as an antireflection film can be provided with an extra adhesion step. It can be applied without accompanying.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not restrict | limited at all by the following Example.

The materials and test methods used in the following examples and comparative examples are as follows.
material
Adhesive:
(1) (A-1): Ethyl acetate solution of acrylic acid ester copolymer (hydroxyl group) (solid content 25% by mass); polymer composition = acrylic acid-nbutyl (90% by mass) + methyl acrylate (9% by mass) + 2-hydroxyethyl acrylate (1% by mass), mass average molecular weight = 1,200,000, Tg = −45 ° C.
(2) Comparison (A-1): Ethyl acetate solution of acrylic acid ester copolymer (acrylic acid type) (solid content 25% by mass); composition of polymer = acrylic acid-nbutyl (98% by mass) + acrylic Acid (2% by mass), mass average molecular weight = 1,200,000, Tg = −50 ° C.
(3) Comparison (A-1) ′: Ethyl acetate solution of acrylic acid ester copolymer (acrylic acid type) (solid content: 25 mass%); Polymer composition = acrylic acid-n-butyl (97.5 mass%) ) + Acrylic acid (2% by mass) + 2-hydroxyethyl acrylate (0.5% by mass), mass average molecular weight = 1,200,000, Tg = −50 ° C.
(4) Comparison (A-1) ": acrylic resin toluene solution for coating (solid content 40 mass%), two-component curing type, mass average molecular weight = 20,000, Tg = 25 ° C
(5) (A-2): Ethyl acetate solution of acrylic ester (co) polymer (solid content 40% by mass), polymer composition = acrylic acid-n-butyl (100%), mass average molecular weight = 5 000, Tg = −55 ° C.

NIR cutting agent:
(1) (B) Gold nanorods: Au-050316 (product name), manufactured by Mitsubishi Materials, gold nanorod toluene dispersion (solid content 5 mass%); absorption wavelengths: 962 nm (absorbance 0.64) and 510 nm (absorbance 0. 0). 15); long axis average length of gold nanorods 50 nm, short axis average length 8 nm, aspect ratio 6.25
(2) Dye (phthalocyanine-based) (for comparison): TX-EX-906B (trade name) (manufactured by Nippon Shokubai)
(3) Dye (Diimonium) (for comparison): IRG-022 (trade name) (manufactured by Nippon Kayaku)

Cross-linking agent:
(1) Polyisocyanate A: xylylene diisocyanate (XDI)
(2) Polyisocyanate B: Triresiocyanate (TDI)
(3) Polyisocyanate C: Hexamethylene diisocyanate (HMDI)

Test method (1) Dispersibility:
Obtained in Examples and Comparative Examples on a silicone resin coated surface of a release film made of a biaxially stretched polyethylene terephthalate film (Mitsubishi Chemical Polyester Film Co., Ltd., trade name: MRF75) having a thickness of 75 μm and coated with a silicone resin on one side. The pressure-sensitive adhesive composition was applied and bonded to a 100 μm thick biaxially stretched polyethylene terephthalate film (trade name: Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.). A pressure-sensitive adhesive sheet member having a pressure-sensitive adhesive layer having a thickness of 25 μm was obtained by drying at 100 ° C. for 1 minute. A small piece having a length of 100 mm and a width of 100 mm was cut out from the pressure-sensitive adhesive sheet member, and the release film of the small piece was peeled off and stuck on a commercially available soda lime glass (thickness: 1.1 mm) to obtain a test sample. Using this test sample, the wavelength of the near red part (850 to 1100 nm) is measured by measuring the transmittance with an ultraviolet visible infrared spectrophotometer (SolidSpec-3700 manufactured by Shimadzu Corporation) according to JIS-K-7361. The minimum light transmittance of the region was determined, and the dispersibility was determined according to the following criteria.
○: The minimum light transmittance is 10% or less.
X: The minimum light transmittance exceeds 10%.
In addition, since the comparative example 8 is a coating composition and does not have adhesiveness, since a test sample cannot be produced by the same method as described above, a test sample was produced by the following method. That is, the composition obtained in Comparative Example 8 was applied to a biaxially stretched polyethylene terephthalate film having a thickness of 100 μm (product name: Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.), and dried at 100 ° C. for 1 minute. A sheet member having a coating layer having a thickness of 5 μm was obtained. A small sample having a length of 100 mm and a width of 100 mm was cut out from the sheet member to obtain a test sample.

(2) Heat resistance:
The test sample obtained in the above (1) was treated under constant temperature conditions of 80 ° C. and Dry for 500 hours, and the heat resistance (deterioration resistance of NIR cut performance) was evaluated. By using the test sample after the above treatment and measuring the transmittance with an ultraviolet-visible infrared spectrophotometer (SolidSpec-3700 manufactured by Shimadzu Corporation) according to JIS-K-7361, the near red part (850 to 1100 nm). ) Was determined and the heat resistance was determined according to the following criteria.
○: The minimum light transmittance is 10% or less.
X: The minimum light transmittance exceeds 10%.

(3) Visible light average transmittance:
Using the test sample obtained in (1) above, the transmittance was measured with an ultraviolet-visible infrared spectrophotometer (SolidSpec-3700 manufactured by Shimadzu Corporation) according to JIS-K-7361, and a wavelength of 380 to 780 nm. The visible light average transmittance of the area was determined.

(4) Minimum light transmittance in the near red part:
In the transmittance measured in (3) above, the bottom transmittance of the near red portion (850 to 1100 nm) was defined as the minimum light transmittance.

(5) Tackiness:
The adhesive sheet member obtained in (1) above is cut into a tape having a width of 25 mm, the release film is peeled off, and the surface of the exposed adhesive composition is reciprocated once by a rubber roller weighing 2 kg. A test piece was obtained by sticking to lime glass (thickness: 1.1 mm). After pasting, in accordance with JIS-Z-0237, the sample was left for 25 minutes in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50%, and then one end of the test piece was pulled in the 180 ° direction at a speed of 300 mm / min. Peeled from the plate. The force (strength) required to peel the test piece was measured, and this value was defined as the adhesive strength (N / 25 mm).

Examples 1-3 and Comparative Examples 1-8
A pressure-sensitive adhesive, a NIR cut agent, and a crosslinking agent were mixed in the blending amounts shown in Table 1 (expressed in terms of mass ratio of solid content), and a pressure-sensitive adhesive composition was prepared using methyl ethyl ketone as a diluent solvent. The above tests (1) to (5) were performed using the obtained composition. The results are shown in Table 1.

  As is clear from Table 1, the pressure-sensitive adhesive compositions of Examples 1 to 3 are excellent in dispersibility, heat resistance, and adhesiveness, and have a suitable visible light average transmittance and minimum light transmittance in the near red part. It is useful as a pressure-sensitive adhesive having a NIR cut performance.

On the other hand, the composition of Comparative Examples 1 to 3 using an acrylic ester copolymer having a carboxyl group as the component (A-1) causes aggregation without gold nanorods being dispersed during preparation of the composition, As a result, NIR cut performance was not obtained. In Comparative Examples 1 to 3, since the NIR cut performance was not already obtained at the stage of preparing the composition, the heat resistance test was not performed.
The composition of Comparative Example 4 in which the amount of the component (B) is less than the range of the present invention has a high minimum light transmittance in the near red part, and thus NIR cut performance is insufficient. The compositions of Comparative Examples 5 to 7 using dyes as the component (B) had poor heat resistance, and the minimum light transmittance in the near red part had already reached 70% or more after 24 hours at 80 ° C.

The composition of Comparative Example 8 using an acrylic resin for coating as the component (A-1), that is, an acrylic resin having a small molecular weight, did not exhibit adhesiveness and could not be used as an adhesive. Therefore, in order to apply this as a NIR cut layer to a plasma display panel, it is necessary to separately apply and paste an adhesive layer, and further to apply a functional layer such as an antireflection film, The process of applying and sticking another adhesive layer is required.

Example 4
The pressure-sensitive adhesive composition of the present invention was applied to a plasma display panel, and workability when the plasma display panel was provided with an NIR cut function and an antireflection function was examined. The pressure-sensitive adhesive composition of Example 1 was used, and the anti-reflection film was RT-PAR001 (trade name) manufactured by Riken Technos (a biaxially stretched polyethylene terephthalate film having a thickness of 100 μm, a hard coat layer, a high refractive index layer, a low An antireflection film coated with a refractive index layer) was used. As described above, since the pressure-sensitive adhesive composition of the present invention has adhesiveness and NIR cut performance, the pressure-sensitive adhesive composition of the present invention is applied to a plasma display panel, and an antireflection film is applied thereon. The NIR cut function and the antireflection function could be imparted only by this. The results are shown in Table 2 together with the results of tests (3) and (4).

Comparative Example 9
In Example 4, instead of the pressure-sensitive adhesive composition of Example 1, an NIR cut film containing IRG-022 (trade name) (diimonium dye) manufactured by Nippon Kayaku as an NIR cut agent was used. Since this NIR cut film does not have adhesiveness, it is necessary to apply the pressure-sensitive adhesive layer (1) in order to provide the NIR cut film as shown in the configuration of Table 2 below, and to provide the antireflection film. In addition, it was necessary to apply another pressure-sensitive adhesive layer (2). In addition, the composition which does not contain a gold nanorod in the adhesive composition of Example 1 was used as an adhesive layer (1) and (2). The results are shown in Table 2 together with the results of tests (3) and (4).

The pressure-sensitive adhesive composition of the present invention is excellent in heat resistance and light resistance, has good visible light transmittance, and has a sufficient absorption function (NIR cut function) for near infrared light having a wavelength of 850 to 1100 nm. . Therefore, when this is applied to an optical application, particularly a plasma display panel, it can be provided with a NIR cut function without an extra adhesion step, and other functional layers such as an antireflection film can be provided with an extra adhesion step. It can be applied without accompanying.

Claims (10)

(A-1) It has one or more functional groups selected from a hydroxyl group, a glycidyl group, an amide group and an N-substituted amide group, does not contain a carboxyl group, and has a mass average molecular weight of 400,000 to 2.5 million. A pressure-sensitive adhesive composition comprising 100 parts by weight of a (meth) acrylic acid ester copolymer and 0.08 to 2.0 parts by weight of (B) gold nanorods. (A-1) It has one or more functional groups selected from a hydroxyl group, a glycidyl group, an amide group and an N-substituted amide group, does not contain a carboxyl group, and has a mass average molecular weight of 400,000 to 2.5 million. A (meth) acrylic acid ester copolymer and (A-2) a (meth) acrylic acid ester (co) polymer having a weight average molecular weight of 1,000 to 50,000 are (A-1) / (A- 2) = 100-20 parts by mass of a mixture containing at a mass ratio of 0.5-20, and (B) 0.08-2.0 parts by mass of gold nanorods. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the component (A-1) has a glass transition temperature of 0 ° C or lower. The pressure-sensitive adhesive composition according to claim 2 or 3, wherein the glass transition temperature of the component (A-2) is -80 to 230 ° C.   The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the particle size of the gold nanorod is 100 nm or less.   6. The pressure-sensitive adhesive composition according to claim 1, wherein the visible light average transmittance at a wavelength of 380 to 780 nm is 30 to 90%.   The pressure-sensitive adhesive composition according to claim 1, wherein a minimum light transmittance in a wavelength region of 850 to 1100 nm is 10% or less.   The adhesive sheet member which has a base material layer and the adhesive composition of any one of Claims 1-7 is coated on the at least single side | surface.   The pressure-sensitive adhesive sheet member according to claim 8, wherein the pressure-sensitive adhesive sheet member is used for optical applications.   The pressure-sensitive adhesive sheet member according to claim 9, which is used in a plasma display panel.