JP2014193528A - Adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive sheet excellent in oligomer sealability.SOLUTION: There is provided an adhesive sheet manufactured by laminating an adhesive agent layer, a polyester film and a resin layer in the order, the resin layer is a cured coating layer manufactured by curing a composition for forming the resin layer containing (A) 50 mass% to 80 mass% of a bisphenol A-type epoxy compound, (B) 5 mass% to 30 mass% of a polyester compound, (C) 10 mass% to 40 mass% of a polyfunctional amino compound and (D) 0.5 mass% to 4 mass% of terminal reactive polydimethylsiloxane, and a ΔHAZE (haze) value which is an absolute value of difference between an initial HAZE value of the adhesive sheet and a post-heating HAZE (haze) value after heating the adhesive sheet at 150°C for 2 hours is 0.15% or less.

Description

  The present invention relates to an adhesive sheet. In particular, the present invention relates to a pressure-sensitive adhesive sheet in which a resin layer provided on the back surface of the base material opposite to the pressure-sensitive adhesive layer also functions as a release layer.

  For example, in the manufacturing process of a capacitive touch panel, when annealing a transparent electrode layer such as ITO (Indium Tin Oxide) deposited on the hard coat layer, a protective sheet is bonded to the hard coat layer side. .

  As such a protective sheet, when a conventional pressure-sensitive adhesive sheet using a heat-resistant polyester film as a base material is used as a protective sheet, oligomers in the polyester film precipitate during the annealing treatment. When the hard coat layer with the protective sheet attached and the transparent electrode layer on the surface of the hard coat layer are rolled in the manufacturing process, the oligomer adheres to the transparent electrode layer or the transparent electrode layer is damaged. There are problems such as.

  For example, in Patent Document 1, a movable electrode film having a hard coat layer formed on the upper surface and a movable electrode formed on the lower surface, and a fixed electrode support having a fixed electrode formed on the upper surface, the movable electrode and the fixed electrode are formed. Disclosed is a transparent touch panel in which a transparent shrinkable resin layer is formed between a movable electrode film and a movable electrode (ITO) in a resistive film type transparent touch panel arranged so that the opposite surfaces face each other via a spacer Has been. With this configuration, oligomer precipitation from the movable electrode film is suppressed.

Japanese Patent Laid-Open No. 7-13695

  However, in the proposal of Patent Document 1, the oligomer precipitation suppressing effect, that is, the oligomer sealing property is not sufficient. Therefore, a pressure-sensitive adhesive sheet that further enhances the oligomer sealing property is desired.

  This invention makes it a subject to provide the adhesive sheet excellent in oligomer sealing property in view of the said problem.

Such an object is achieved by the present inventions (1) to (8) below.
(1) An adhesive sheet in which an adhesive layer, a polyester film, and a resin layer are laminated in order,
The resin layer is
(A) 50 mass% or more and 80 mass% or less of bisphenol A type epoxy compound,
(B) 5% by mass or more and 30% by mass or less of a polyester compound;
(C) 10% by mass or more and 40% by mass or less of a polyfunctional amino compound;
(D) 0.5 mass% or more and 4 mass% or less of terminal reactive polydimethylsiloxane;
Is a cured film obtained by curing a resin layer forming composition containing
The ΔHAZE (haze) value, which is the absolute value of the difference between the initial HAZE value of the pressure-sensitive adhesive sheet and the post-heating HAZE value after heating the pressure-sensitive adhesive sheet at 150 ° C. for 2 hours, is 0.15%. A pressure-sensitive adhesive sheet characterized by:
(2) The pressure-sensitive adhesive sheet according to (1), wherein the bisphenol A type epoxy compound has a mass average molecular weight of 1 × 10 ⁴ or more and 5 × 10 ⁴ or less.
(3) The pressure-sensitive adhesive sheet according to the above (1) or (2), wherein the glass transition temperature (Tg) of the polyester compound is 0 ° C. or higher and 50 ° C. or lower.
(4) The above (1) to (3), wherein the resin layer is a cured film obtained by heating a coating layer formed by coating an organic solvent solution of the resin layer forming composition on the polyester film. The adhesive sheet as described in any one.
(5) The pressure-sensitive adhesive sheet according to any one of (1) to (4), wherein the resin layer has a thickness of 50 nm to 500 nm.
(6) The pressure-sensitive adhesive sheet according to any one of (1) to (5), wherein the terminal-reactive polydimethylsiloxane is a terminal carbinol-modified hydroxyl group-containing polydimethylsiloxane.
(7) The pressure-sensitive adhesive sheet according to any one of (1) to (6), which is used in a touch panel manufacturing process.
(8) The pressure-sensitive adhesive sheet according to (7), wherein the touch panel is a capacitive type.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive sheet excellent in the oligomer sealing property can be provided.

FIG. 1 is a schematic cross-sectional view illustrating an example of a layer structure of an adhesive sheet. FIG. 2 is a schematic cross-sectional view showing an example of applying an adhesive sheet as a protective material for an ITO film. FIG. 3 is a schematic cross-sectional view showing an example of the pressure-sensitive adhesive sheet wound around the core material in a roll shape.

  Hereinafter, the present invention will be described in detail. In addition, this invention is not limited by the content described in the following embodiment and an Example. In addition, constituent elements in the embodiments and examples described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the embodiments and examples described below may be appropriately combined or may be appropriately selected and used.

  FIG. 1 is a schematic cross-sectional view illustrating a configuration example of an adhesive sheet according to the present embodiment. FIG. 2 is a schematic cross-sectional view showing an example when the pressure-sensitive adhesive sheet according to this embodiment is used as a protective material for an ITO film. FIG. 3 is a schematic cross-sectional view showing an example of the pressure-sensitive adhesive sheet wound around the core material in a roll shape.

  As shown in FIG. 1, the adhesive sheet 1 which concerns on this embodiment has laminated | stacked the adhesive layer 2, the polyester film 3, and the resin layer 4 in this order. The resin layer 4 includes (A) 50% by mass to 80% by mass of a bisphenol A type epoxy compound, (B) 5% by mass to 30% by mass of a polyester compound, and (C) 10% by mass to 40% by mass. A cured film obtained by curing a resin layer forming composition containing the following polyfunctional amino compound and (D) 0.5% by mass or more and 4% by mass or less of terminal-reactive polydimethylsiloxane. The ΔHAZE value, which is the absolute value of the difference between the initial HAZE value and the post-heating HAZE value after heating the adhesive sheet 1 at 150 ° C. for 2 hours, is 0.15% or less.

  Hereinafter, each layer which comprises the adhesive sheet 1 is demonstrated in order.

[Adhesive layer]
The pressure-sensitive adhesive layer 2 is formed from a conventionally known pressure-sensitive adhesive composition such as an acrylic pressure-sensitive adhesive, a natural rubber-based pressure-sensitive adhesive, or a synthetic rubber-based pressure-sensitive adhesive. When used as a protective sheet for annealing an ITO film, the pressure-sensitive adhesive layer 2 preferably has removability.

  As an acrylic adhesive, the adhesive composition containing an acrylic polymer is mentioned, for example. The acrylic polymer is obtained by polymerizing a monomer composition containing (meth) acrylic acid ester, a vinyl monomer containing a reactive functional group, and the like.

(Meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, (meth ) Isobutyl acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth ) 2-ethylhexyl acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, etc. And (meth) acrylic acid alkyl esters having 1 to 20 carbon atoms in the alkyl group of the ester moiety. Here, “(meth) acryl” represents “acryl” or “methacryl”.
These acrylic monomers can be used alone or in combination of two or more.

  Examples of the vinyl monomer containing a reactive functional group described above include hydroxyl group-containing (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate; 1,4-di (Meth) acryloxyethyl pyromellitic acid, 4- (meth) acryloxyethyl trimellitic acid, N- (meth) acryloyl-p-aminobenzoic acid, 2- (meth) acryloyloxybenzoic acid, N- (meth) Carboxyl group-containing (meth) acrylates such as acryloyl-5-aminosalicylic acid, acrylic acid, and methacrylic acid; aminoethyl (meth) acrylate, ethylaminoethyl (meth) acrylate, aminopropyl (meth) acrylate, ethylaminopropyl (meth) Such as acrylate Primary to secondary amino group-containing (meth) acrylate; and 2- (methylthio) containing a thiol group such as ethyl methacrylate (meth) acrylate. These may be used alone or in combination of two or more.

  The content of the structural unit derived from the vinyl monomer containing a reactive functional group in the acrylic polymer is preferably 0.01 mol% to 20 mol%, and preferably 0.1 mol% to 10 mol%. Is more preferable.

  Moreover, it is preferable that the adhesive composition contains a crosslinking agent. The crosslinking agent is preferably at least one selected from the group consisting of a polyfunctional amino compound, a polyfunctional isocyanate compound, a polyfunctional epoxy compound, a polyfunctional aziridine compound, a polyfunctional oxazoline compound, and a polyfunctional metal compound. As the cross-linking agent, for example, a component that cross-links the pressure-sensitive adhesive by reacting with a reactive functional group of the acrylic polymer can be used.

  When the pressure-sensitive adhesive composition contains a crosslinking agent, the blending amount of the crosslinking agent is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the acrylic polymer, and 1 to 20 parts by mass. It is more preferable that Thereby, the adhesive layer excellent in adhesive performance and cohesion force can be formed.

  Further, the pressure-sensitive adhesive composition may contain a curing accelerator, a curing retarder and the like.

  Although the thickness of the adhesive layer 2 is not specifically limited, For example, they are 5 micrometers or more and 50 micrometers or less, Preferably they are 10 micrometers or more and 40 micrometers or less.

[Polyester film]
The polyester film 3 functions as a base material layer for forming the pressure-sensitive adhesive layer 2 and the resin layer 4. The polyester film 3 has heat resistance that does not shrink or melt so as to cause a defect even when annealing is performed at a high temperature. Examples of the polyester film 3 include films of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and the like. The thickness of the polyester film can be appropriately selected depending on the application. For example, when it is used as a protective material during the annealing treatment of the ITO film, it is preferably 25 μm or more and 300 μm or less, and 30 μm or more and 200 μm or less. It is more preferable. In this range, flexibility suitable for the roll-to-roll manufacturing can be obtained while maintaining the strength of the pressure-sensitive adhesive sheet 1.

[Resin layer]
The resin layer 4 includes (A) 50% by mass to 80% by mass of a bisphenol A type epoxy compound, (B) 5% by mass to 30% by mass of a polyester compound, and (C) 10% by mass to 40% by mass. It is the cured film which hardened the composition for resin layer formation containing the following polyfunctional amino compounds and the terminal reactive polydimethylsiloxane of (D) 0.5 mass% or more and 4 mass% or less. Hereinafter, each component which comprises the composition for resin layer formation is demonstrated.

<(A) Bisphenol A type epoxy compound>
Examples of the bisphenol A type epoxy compound include bisphenol A diglycidyl ether. Hereinafter, the bisphenol A type epoxy compound is appropriately referred to as component (A).

The mass average molecular weight (Mw) of the component (A) is preferably 1 × 10 ⁴ or more and 5 × 10 ⁴ or less. In this range, a film having an appropriate crosslinking density can be obtained. If the average molecular weight (Mw) is too large, the crosslinking density required for the film cannot be obtained, and oligomers are likely to precipitate. If the average molecular weight (Mw) is too small, the film becomes too hard.

<(B) Polyester compound>
(B) It does not specifically limit as a polyester compound, It can select from the well-known thing known as a polyester compound suitably, and can use it. A specific polyester compound is a resin obtained by a condensation reaction between a polyhydric alcohol and a polybasic acid, which is modified with a condensate of a dibasic acid and a dihydric alcohol or a non-drying oil fatty acid. Non-convertible polyester compounds, and convertible polyester compounds that are condensates of dibasic acids and trivalent or higher alcohols can be used, and any of these can be used in the present invention.

  Examples of the polyhydric alcohol used as a raw material for the polyester compound include dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, and neopentyl glycol, glycerin, trimethylolethane, and triethylene glycol. Examples thereof include trihydric alcohols such as methylolpropane, and polyhydric alcohols having a valence of 4 or more such as diglycerin, triglycerin, pentaerythritol, dipentaerythritol, mannitol, and sorbit. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Examples of the polybasic acid include aromatic polybasic acids such as phthalic anhydride, terephthalic acid, isophthalic acid, and trimetic anhydride, aliphatic saturated polybasic acids such as succinic acid, adipic acid, and sebacic acid, maleic acid, Diels such as aliphatic unsaturated polybasic acids such as maleic anhydride, fumaric acid, itaconic acid, citraconic anhydride, cyclopentadiene-maleic anhydride adduct, terpene-maleic anhydride adduct, rosin-maleic anhydride adduct -The polybasic acid by an alder reaction etc. can be mentioned. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Furthermore, examples of the non-drying oil fatty acid as a modifying agent include octylic acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, eleostearic acid, ricinoleic acid, dehydrated ricinoleic acid, or palm Oil, flaxseed oil, tung oil, castor oil, dehydrated castor oil, soybean oil, safflower oil, and fatty acids thereof. These may be used individually by 1 type and may be used in combination of 2 or more type. Moreover, also as a polyester compound, 1 type may be used independently and 2 or more types may be used in combination.

  (B) The polyester compound preferably has an active hydrogen group such as a hydroxyl group, a carboxyl group, or an amino group that serves as a base point for the crosslinking reaction, and particularly preferably has a hydroxyl group. The hydroxyl value of the (B) polyester compound is preferably 5 mgKOH / g or more and 500 mgKOH / g or less, more preferably 10 mgKOH / g or more and 300 mgKOH / g or less.

  The number average molecular weight (Mn) of the (B) polyester compound is preferably 500 or more and 10,000 or less, and more preferably 1000 or more and 5000 or less.

  Moreover, it is preferable that the glass transition temperature Tg of (B) polyester compound is 0 degreeC or more and 50 degrees C or less.

  By using a polyester compound having a molecular weight and a glass transition temperature in the above ranges, moderate flexibility can be imparted to the cured film forming the resin layer 4.

  Hereinafter, the polyester compound is appropriately referred to as component (B).

<(C) Polyfunctional amino compound>
(C) Examples of polyfunctional amino compounds include melamine compounds such as hexamethoxymethyl melamine, methylated melamine compounds, butylated melamine compounds; urea compounds such as methylated urea compounds and butylated urea compounds; methylated benzoguanamine resins; Examples thereof include benzoguanamine compounds such as butylated benzoguanamine compounds; diamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, N, N′-diphenylethylenediamine, and p-xylylenediamine. From the viewpoint of curability, hexamethoxymethylmelamine is preferable.

  Hereinafter, the polyfunctional amino compound is appropriately referred to as component (C).

<(D) Terminal reactive polydimethylsiloxane>
(D) The terminal reactive polydimethylsiloxane preferably has an active hydrogen group such as a hydroxyl group, a carboxyl group, or an amino group as a reaction base point, and particularly preferably has a hydroxyl group. Specifically, terminal carbinol-modified hydroxyl group-containing polydimethylsiloxane is preferred. The reactive group may be present at either one end or both ends.

  By blending this terminal reactive polydimethylsiloxane, release property is imparted to the resin layer 4, and a single-layer pressure-sensitive adhesive sheet 1 is obtained in which the resin layer 4 functions as a release layer without providing a separate release layer. It is done.

  Hereinafter, the terminal reactive polydimethylsiloxane is appropriately referred to as a component (D).

<(E) Acidic catalyst>
Furthermore, in order to accelerate the curing reaction, the resin layer forming composition may contain a known acidic catalyst (E) such as hydrochloric acid or p-toluenesulfonic acid, if desired.

  Hereinafter, the acidic catalyst is appropriately referred to as component (E).

<Hardened film>
The cured film which is the resin layer 4 includes the components (A) to (D) described above with (A) 50% by mass to 80% by mass, (B) 5% by mass to 30% by mass, and (C) 10 The composition for resin layer formation which is contained at a blending ratio of not less than 40% by mass and not more than 40% by mass and (D) not less than 0.5% by mass and not more than 4% by mass is cured. When the component (E) is blended, the content of the component (E) is preferably 1% by mass or more and 5% by mass or less.

  According to the blending ratio in the above range, oligomer precipitation in the resin layer 4 can be suppressed as shown in Examples described later. As a result, the pressure-sensitive adhesive sheet 1 with improved oligomer sealing can be provided.

<HAZE value>
The oligomer suppression effect in the resin layer is confirmed by measuring the ΔHAZE value, which is the absolute value of the difference between the initial HAZE value of the pressure-sensitive adhesive sheet and the post-heating HAZE value after heating the pressure-sensitive adhesive sheet at 150 ° C. for 2 hours. it can. By using the resin layer forming composition having the above composition, the ΔHAZE value can be made 0.15% or less. The initial HAZE value of the adhesive sheet corresponds to the HAZE value before heating the adhesive sheet at 150 ° C. for 2 hours. Further, the ΔHAZE value is preferably 0.1% or less, and more preferably 0.08% or less.

  Conventionally, oligomer precipitation was only visual appearance evaluation, but the present inventors newly found an index for quantitatively evaluating the degree of oligomer precipitation that adversely affects the transparent electrode layer. This quantitative evaluation can effectively prevent damage to the transparent electrode layer and contamination with foreign matter.

[Formation of cured film]
The cured film to be a resin layer is formed by applying a solution obtained by dissolving a resin layer forming composition having the above composition in an organic solvent to the polyester film to be a base layer to form a coating layer. The upper coating layer can be obtained by heat curing at a temperature of 120 to 170 ° C. for 5 seconds to 5 minutes.

  As the organic solvent, ordinary ones can be used. Specifically, aromatic solvents such as benzene, toluene and xylene, aliphatic solvents such as normal hexane and normal heptane, ethyl acetate and butyl acetate. And ester solvents such as methyl ethyl ketone, methyl isobutyl ketone, ketone solvents such as cyclohexanone and cyclopentanone, and alcohol solvents such as ispropyl alcohol and methanol.

<Thickness of resin layer>
The cured film obtained by the above method preferably has a thickness of 50 nm to 500 nm, more preferably 80 nm to 300 nm. Oligomer precipitation can be effectively suppressed in this range of film thickness. If the thickness of the cured film is too thin, the effect of suppressing oligomer precipitation cannot be sufficiently obtained, and if it is too thick, after forming a resin layer on the base material layer, it is rolled into a core material such as paper, plastic or metal. It becomes difficult to take up when taking up.

<Application>
Although the adhesive sheet 1 which concerns on this embodiment is used suitably as a protection sheet at the time of annealing an ITO film in the capacitive touch panel manufacturing process, for example, it is not limited to this.

  In the manufacturing process of the capacitive touch panel, the ITO film is annealed at a temperature of about 150 ° C. At this time, the adhesive sheet 1 according to this embodiment is used as a protective sheet for protecting the ITO film. Can do.

  As shown in FIG. 2, the ITO film 5 has a hard coat layer 7 on both sides of a support 6, and an ITO film (indium tin oxide film) 8 is sputtered, CVD, PVD on the surface of one hard coat layer 7. Or the like. The pressure-sensitive adhesive layer 2 of the pressure-sensitive adhesive sheet 1 illustrated in FIG. 1 is bonded to the surface of the hard coat layer 7 opposite to the surface on which the ITO film 8 is deposited.

  As shown in FIG. 2, when the ITO film 5 is annealed with the pressure-sensitive adhesive sheet 1 adhered to the hard coat layer 7, crystallization of the ITO proceeds to produce a low-resistance transparent electrode layer. it can.

  Furthermore, according to the pressure-sensitive adhesive sheet of the present embodiment, it is preferable that the oligomer contained in the polyester film 3 is bleed or crystals derived from the oligomer are deposited on the surface of the resin layer also in the annealing treatment and the subsequent heat treatment. Can be suppressed. Therefore, it is possible to suppress the entry of minute foreign substances derived from oligomers that are inconvenient as a touch panel and damage to the transparent electrode layer. The oligomer contained in the polyester film 3 is derived from a polyester-forming monomer, dimer, trimer, or the like.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these.

<Preparation of adhesive>
Mixing 100 parts by mass of an acrylic pressure-sensitive adhesive (Toyochem “BPS5227-1” (trade name)) with 3 parts by mass of a curing agent (“BXX5134” (trade name) made by Toyochem) and 30 parts by mass of ethyl acetate as a diluent solvent Then, the pressure-sensitive adhesive was adjusted.

[Example 1]
(A) Bisphenol A type epoxy compound (“EPICLON H-360” (trade name) manufactured by DIC, solid content concentration: 40%, mass average molecular weight: 25000) in 100 parts by mass, (B) polyester compound (Toyobo Co., Ltd.) 19.05 parts by weight of a diluted toluene solution (solid content concentration 30%) of “Byron GK680” (trade name), number average molecular weight: 6000, glass transition temperature: 10 ° C., (C) hexamethoxymethylmelamine (Nippon Cytec) 10.86 parts by mass of “Cymel 303” (trade name) manufactured by Industries, Inc., (D) Carbinol-modified polydimethylsiloxane (Shin-Etsu Chemical Co., Ltd. “KF-6002” (trade name), number average molecular weight: 3000, (Hydroxyl value: 35 mg KOH / g) 0.57 parts by mass was added, and solidified with a mixed solvent of toluene / MEK = 50/50 wt%. After diluting and stirring so that the form content is 3 wt%, 2.86 parts by mass of (E) methanol solution of p-toluenesulfonic acid (solid content concentration 50%) is added to obtain a resin layer forming composition. Obtained.

  A biaxially stretched polyethylene terephthalate film (“Lumirror T60” (trade name) thickness 50 μm, manufactured by Toray Industries, Inc.) as a base material is obtained by using a roll-to-roll method. After coating uniformly on one side by the Meyer bar coating method so that the thickness after drying becomes 150 nm, it is processed so that it passes through an oven in which hot air at 150 ° C. blows at a wind speed of 8 m / min in 20 seconds. The base material for adhesive sheets which adjusted the speed | rate and formed the thermosetting resin layer of width 1050mm and length 4000m wound up by the core material made from ABS was obtained.

  Next, it is applied by roll-to-roll method so that the pressure-sensitive adhesive thickness after drying is 20 μm on the untreated surface of the substrate for the pressure-sensitive adhesive sheet, dried at 100 ° C. for 2 minutes, and then directly made of ABS core material. The pressure-sensitive adhesive sheet wound in a roll shape was obtained by winding the material around.

  FIG. 3 is a schematic cross-sectional view for explaining the pressure-sensitive adhesive sheet wound around the core material 9 in a roll shape. As shown in FIG. 3, the pressure-sensitive adhesive sheet wound around the core material 9 in a roll shape is in a state where the pressure-sensitive adhesive layer 2 and the resin layer 4 are in direct contact with each other. Since the resin layer 4 also serves as a release layer, even if a separate release layer is not provided, even if the adhesive layer 2 and the resin layer 4 are wound in a state of direct contact as shown in FIG. When pulling out the pressure-sensitive adhesive sheet from the roll body, the pressure-sensitive adhesive layer 2 and the resin layer 4 are peeled off at their interfaces, and the pressure-sensitive adhesive sheet can be pulled out.

[Example 2]
As the composition of the resin layer forming composition, (A) 100 parts by mass of bisphenol A type epoxy compound, (B) 22.22 parts by mass of polyester compound, (C) 19.33 parts by mass of hexamethoxymethylmelamine, D) A pressure-sensitive adhesive sheet operated in the same manner as in Example 1 except that both ends carbinol-modified polydimethylsiloxane was 0.67 parts by mass, and (E) a methanol solution of p-toluenesulfonic acid was 3.33 parts by mass. Got.

[Example 3]
As the composition of the resin layer forming composition, (A) 100 parts by mass of bisphenol A type epoxy compound, (B) 44.44 parts by mass of polyester compound, (C) 12.67 parts by mass of hexamethoxymethylmelamine, ( D) A pressure-sensitive adhesive sheet operated in the same manner as in Example 1 except that both ends carbinol-modified polydimethylsiloxane was 0.67 parts by mass, and (E) a methanol solution of p-toluenesulfonic acid was 3.33 parts by mass. Got.

[Example 4]
(A) As a bisphenol A type epoxy compound, “EPICLON EXA-123” (trade name) manufactured by DIC (solid content concentration: 30%, mass average molecular weight: 45000) in 100 parts by mass, (B) polyester compound (Toyobo Co., Ltd.) “Byron GK680” (trade name), number average molecular weight: 6000, glass transition temperature: 10 ° C.) in toluene diluted solution (solid content concentration: 30%) 14.29 parts by mass, (C) hexamethoxymethylmelamine ( “Cymel 303” (trade name) by 8.14 parts by mass of Nippon Cytec Industries, Ltd. (D) 0.43 parts by mass of carbinol-modified polydimethylsiloxane at both ends was added, and a mixed solvent of toluene / MEK = 50/50 wt% After diluting to 3 wt% and stirring, (E) methanol solution of p-toluenesulfonic acid (solid content concentration 50%) Was added in the same manner as in Example 1 except that 2.14 parts by mass was added to obtain a resin layer forming composition.

[Example 5]
(B) Except for using a toluene diluted solution (solid content concentration 30%) of “Byron GK810” (trade name) (number average molecular weight: 6000, glass transition temperature: 46 ° C.) manufactured by Toyobo Co., Ltd. as the polyester compound, A pressure-sensitive adhesive sheet was obtained by operating in the same manner as in Example 1.

[Example 6]
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the coating amount was changed so that the film after drying of the resin layer was 300 nm.

[Example 7]
The composition of the resin layer forming composition is (A) 100 parts by mass of bisphenol A type epoxy compound, (B) 19.05 parts by mass of polyester compound, (C) 9.71 parts by mass of hexamethoxymethyl melamine, (D ) A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 1.71 parts by mass of carbinol-modified polydimethylsiloxane at both ends and 2.86 parts by mass of methanol solution of (E) p-toluenesulfonic acid. It was.

[Comparative Example 1]
The composition of the resin layer forming composition is (A) 100 parts by mass of bisphenol A type epoxy compound, (C) 9.5 parts by mass of hexamethoxymethyl melamine, and (D) 0. An adhesive sheet was obtained in the same manner as in Example 1 except that 5 parts by mass and 2.5 parts by mass of the methanol solution of (E) p-toluenesulfonic acid were used.

[Comparative Example 2]
The composition of the resin layer forming composition is (A) 100 parts by mass of bisphenol A type epoxy compound, (B) 222.22 parts by mass of polyester compound, (C) 25.33 parts by mass of hexamethoxymethylmelamine, (D ) A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 1.33 parts by mass of carbinol-modified polydimethylsiloxane at both ends and 6.67 parts by mass of methanol solution of (E) p-toluenesulfonic acid. It was.

[Comparative Example 3]
Example 1 except that a 40% toluene diluted solution of “jER 1010” (trade name) (mass average molecular weight 5500) manufactured by Mitsubishi Chemical Corporation was used as the (A) bisphenol A type epoxy compound in the resin layer forming composition. A pressure-sensitive adhesive sheet was obtained in the same manner as described above.

[Comparative Example 4]
As a polyester compound (B) in the resin layer forming composition, a toluene diluted solution (solid content concentration 30%) of “Byron 885” (trade name) (number average molecular weight: 8000, glass transition temperature: 79 ° C.) manufactured by Toyobo Co., Ltd. ) Was used in the same manner as in Example 1 to obtain an adhesive sheet.

[Comparative Example 5]
As a polyester compound (B) in the resin layer forming composition, a toluene diluted solution (solid content concentration of 30) of “Byron BK1001” (trade name) (number average molecular weight: 28000, glass transition temperature: −18 ° C.) manufactured by Toyobo Co., Ltd. %) Was used in the same manner as in Example 1 to obtain an adhesive sheet.

[Comparative Example 6]
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the coating amount was changed so that the thickness of the resin layer after drying was 25 nm.

[Comparative Example 7]
(A) 19.0 parts by mass of (B) polyester compound and (C) 11.4 parts by mass of hexamethoxymethylmelamine are added to 100 parts by mass of bisphenol A type epoxy compound, and a mixed solvent of toluene / MEK = 50/50 wt%. (E) p-Toluenesulfonic acid methanol solution (solid content concentration 50%) was added, and 2.9 parts by mass was added to obtain a resin layer forming composition. The same operation as in Example 1 was performed to obtain a pressure-sensitive adhesive sheet.

[Comparative Example 8]
The composition of the resin layer forming composition is (A) 100 parts by mass of bisphenol A type epoxy compound, (B) 19.05 parts by mass of polyester compound, (C) 8.57 parts by mass of hexamethoxymethyl melamine, (D ) A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 2.86 parts by mass of carbinol-modified polydimethylsiloxane at both ends and 2.86 parts by mass of methanol solution of p-toluenesulfonic acid were used. It was.

[Comparative Example 9]
(D) In the same manner as in Example 1 except that polydimethylsiloxane containing no reactive functional group ("SH200" (trade name) manufactured by Toray Dow Corning Co., Ltd.) was used instead of the carbinol-modified polydimethylsiloxane at both ends. The pressure-sensitive adhesive sheet was obtained by operating.

[Comparative Example 10]
The composition of the resin layer forming composition is (A) 100 parts by mass of bisphenol A type epoxy compound, (B) 33.33 parts by mass of polyester compound, (C) 49 parts by mass of hexamethoxymethyl melamine, (D) both A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 1 part by mass of the terminal carbinol-modified polydimethylsiloxane and 5 parts by mass of the methanol solution of (E) p-toluenesulfonic acid were used.

[Comparative Example 11]
The composition of the resin layer forming composition is (A) 100 parts by mass of bisphenol A type epoxy compound, (B) 35.56 parts by mass of polyester compound, (C) 2.13 parts by mass of hexamethoxymethyl melamine, (D ) A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 0.53 parts by mass of both ends carbinol-modified polydimethylsiloxane and (E) methanol solution of p-toluenesulfonic acid was 2.67 parts by mass. It was.

  Table 1 shows the compositions of the resin layer forming compositions used in Examples 1 to 7 and Comparative Examples 1 to 11 and the thickness of the resin layer after drying.

[Evaluation]
<Calculation of ΔHAZE value>
Samples obtained by cutting out the pressure-sensitive adhesive sheets obtained in Examples 1 to 7 and Comparative Examples 1 to 11 to 5 cm squares were used as test pieces, and a haze meter (“NDH2000” (trade name) manufactured by Nippon Denshoku Industries Co., Ltd.) was used. The initial HAZE value (%) was measured according to JIS K7105 (N = 5 average value).

  In addition, one corner of each test piece was clipped, suspended in a dryer at 150 ° C., heated for 2 hours, and then the HAZE value (%) after heating was measured according to JIS K7105 (average value of N = 5). .

  The absolute value of the value obtained by subtracting the initial HAZE value from the HAZE value after heating was defined as the ΔHAZE value. If the ΔHAZE value is 0.15% or less, the precipitation amount of the polyester oligomer is sufficiently small, and there is no influence on the subsequent steps. Therefore, 0.15% or less is “◯” (good), 0.15% or more Was “x” (defect).

<Measurement of peel force>
The peel strength (feeding peel strength) of the obtained pressure-sensitive adhesive sheet was measured as follows.

  The force required to pull out the pressure-sensitive adhesive sheet wound in a roll shape from the roll was measured with a tensile tester under the conditions of peeling speed: 10 m / min, peeling angle: 180 degrees.

  A peeling force of less than 200 mN / 50 mm was designated as “◯” (good), and a peeling force of 200 mN / 50 mm or more was designated as “x” (defective). When the peeling force is 200 mN / 50 mm or more, there is a risk of causing a feeding failure.

<Transition amount of silicone>
The pressure-sensitive adhesive sheet obtained in a rolled state was pulled out from the roll, and the amount of silicone transferred from the resin layer to the pressure-sensitive adhesive layer was measured for the pulled-out portion.

  The atomic composition of the pressure-sensitive adhesive layer surface of the obtained pressure-sensitive adhesive sheet was measured with an X-ray photoelectron spectrometer (XPS; Quantara SXM (trade name) manufactured by ULVAC-PHI), and the migration amount was determined according to the following formula.

  Silicone transfer amount (Si AC%) = Si / (C + O + N + Si) × 100 (1)

  In the above formula, Si represents a silicon atom, C represents a carbon atom, O represents an oxygen atom, and N represents an atomic concentration (AC%) of a nitrogen atom.

  When the amount of silicone migration was less than 1 AC%, “◯” (good), and when the amount of silicone migration was 1 AC% or more, “x” (bad). When the amount of silicone transfer is 1 AC% or more, there is a possibility that the hard coat surface may be contaminated in the step of peeling after sticking the adhesive sheet to the hard coat surface.

<Result>
Table 2 shows the initial HAZE value, ΔHAZE value, oligomer sealing property, peeling force, peelability, silicone migration amount, and silicone migration property for Examples 1 to 7 and Comparative Examples 1 to 9.

  As is clear from Table 2, in the pressure-sensitive adhesive sheets according to Examples 1 to 7, excellent results were obtained for all evaluation items of oligomer sealing property, peelability, and silicone migration property. On the other hand, in Comparative Examples 1 to 11, although excellent effects could be observed for some evaluation items, an adhesive sheet satisfying all these evaluation items could not be obtained.

DESCRIPTION OF SYMBOLS 1 Adhesive sheet 2 Adhesive layer 3 Polyester film (base material layer)
4 Resin layer 5 ITO film 6 Support 7 Hard coat layer 8 ITO film 9 Core material

Claims (8)

An adhesive sheet in which an adhesive layer, a polyester film, and a resin layer are laminated in order,
The resin layer is
(A) 50 mass% or more and 80 mass% or less of bisphenol A type epoxy compound,
(B) 5% by mass or more and 30% by mass or less of a polyester compound;
(C) 10% by mass or more and 40% by mass or less of a polyfunctional amino compound;
(D) 0.5 mass% or more and 4 mass% or less of terminal reactive polydimethylsiloxane;
Is a cured film obtained by curing a resin layer forming composition containing
The ΔHAZE (haze) value, which is the absolute value of the difference between the initial HAZE value of the pressure-sensitive adhesive sheet and the post-heating HAZE value after heating the pressure-sensitive adhesive sheet at 150 ° C. for 2 hours, is 0.15%. A pressure-sensitive adhesive sheet characterized by: The pressure-sensitive adhesive sheet according to claim 1, wherein the bisphenol A-type epoxy compound has a mass average molecular weight of 1 × 10 ⁴ or more and 5 × 10 ⁴ or less.   The pressure sensitive adhesive sheet according to claim 1 or 2 whose glass transition temperature (Tg) of said polyester compound is 0 ° C or more and 50 ° C or less.   The said resin layer heats the coating layer formed by apply | coating the organic solvent solution of the said composition for resin layer formation to the said polyester film, and makes it a cured film, It is any one of Claim 1 to 3 Adhesive sheet.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the resin layer has a thickness of 50 nm to 500 nm.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the terminal-reactive polydimethylsiloxane is a terminal carbinol-modified hydroxyl group-containing polydimethylsiloxane.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, which is used in a touch panel manufacturing process.   The pressure-sensitive adhesive sheet according to claim 7, wherein the touch panel is a capacitive type.

Images