TW201627443A - Manufacturing method of heat-resistant adhesive sheet and functional film - Google Patents

Abstract

The present invention provides a manufacturing method of a heat-resistant adhesive sheet and a functional film which reduces manufacturing costs of the functional film by simplifying manufacturing steps. The heat-resistant adhesive sheet (1) of this invention is provided with: a peeling film (10) comprising a peeling substrate (11) made of a polyester film, a resin layer (12) arranged on one main surface of the peeling substrate (11), and a peeling agent layer (13) arranged on the other main surface of the peeling substrate (11); an adhesive layer (14) arranged on the peeling agent layer (13); and a substrate film (21) arranged on the adhesive layer (14), wherein the peeling film (10) has a delta haze value, i.e. the absolute difference between the initial haze value and the haze value measured after heating for two hours at 150 DCG C, less than 0.15%.

Description

Heat-resistant adhesive sheet and method for producing functional film

The present invention relates to a method for producing a heat-resistant adhesive sheet having a functional layer and a functional film, and more particularly to a method for producing a heat-resistant adhesive sheet and a functional film using a polyester film as a release substrate.

Conventionally, in the manufacturing process of a touch panel, a transparent conductive film having a transparent electrode layer such as an ITO (Indium Tin Oxide) film is used. The transparent conductive film is provided with a transparent coating layer on one of the main surfaces of the support body, a transparent electrode layer on one hard coating layer, and a peelable layer on the other hard coating layer. The surface protection film is made by adhering a sheet. As an adhesive sheet for the production of a transparent conductive film, an adhesive layer is provided on a base film made of a polyester film having heat resistance (for example, refer to Patent Document 1).

Further, in the manufacturing process of the touch panel, the transparent conductive film is bonded to a glass substrate or the like through an optical adhesive film (Optical Clear Adhesive, hereinafter sometimes referred to as "OCA"). A release film made of a polyester film is usually laminated on both sides of the OCA.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-205567

However, the transparent conductive film is produced by attaching a release substrate having an adhesive layer to the other surface of a transparent conductive film (or a raw material film of a transparent conductive film) having a transparent conductive layer on its surface. Adhesive sheet of protective film of transparent conductive layer. Further, after the adhesive film is attached, the transparent conductive film is subjected to an annealing treatment by heating, and then the release substrate of the adhesive sheet is removed, and a transparent conductive film is attached to the glass substrate or the like through the adhesive layer. For products such as touch panels. As described above, in the manufacturing process of the conventional transparent conductive film, the adhesive sheet which is heat-treated together with the transparent conductive layer must have heat resistance, and it is necessary to adhere the adhesive sheet to the back side of the transparent conductive film on the back side of the transparent conductive film. In the case, there are cases where the manufacturing steps are complicated.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a heat-resistant adhesive sheet and a method for producing a functional film which are excellent in heat resistance and which can reduce the manufacturing cost of the functional film by shortening the manufacturing steps.

The heat-resistant adhesive sheet of the present invention is characterized by comprising a release film comprising a release substrate made of a polyester film, a resin layer provided on one main surface of the release substrate, and a release substrate provided on the release substrate. a release agent layer on the other main surface; an adhesive layer provided on the release agent layer; and a base film provided on the adhesive layer, the initial haze value of the release film is heated at 150 ° C. The Δ haze value of the absolute value of the difference in haze value after heating after an hour is 0.15% or less.

According to this configuration, since the rate of change in the haze value of the release film before and after heating is small, a heat-resistant adhesive sheet excellent in heat resistance can be obtained. Further, since the back surface side of the functional layer on the base film is protected by the release film including the release substrate, the resin layer, and the release agent layer, the back side of the adhesion protection function layer can be omitted in the production of the functional film. The step of protecting the sheet. Therefore, it is possible to realize a heat-resistant adhesive sheet which can reduce the manufacturing cost of the functional film by shortening the manufacturing steps.

In the heat-resistant adhesive sheet of the present invention, the release agent layer is preferably formed by curing an addition reaction type polyfluorene.

In the heat-resistant adhesive sheet of the present invention, the resin layer is cured by a composition for forming a resin layer containing (A) a bisphenol A type epoxy compound, (B) a polyester compound, and (C) a polyfunctional amine group compound. Made. With this configuration, the resin layer layer is provided on one surface of the release substrate by curing the resin layer-forming composition containing the bisphenol A-type epoxy resin compound, the polyester compound, and the polyfunctional amine-based compound. The crosslink density becomes a moderate range. Thereby, the heat-resistant adhesive sheet can prevent the oligomer from being precipitated from the polyester film toward the surface side of the heat-resistant adhesive sheet, and is sticky even to heat resistance. When a sheet is pressed or impacted, cracking of the resin layer can be prevented, and the oligomer can be prevented from leaking out of the crack.

In the heat-resistant adhesive sheet of the present invention, the content of the bisphenol A-type epoxy compound in the resin layer-forming composition is preferably 50% by mass or more and 80% by mass or less, and the content of the polyester compound is 5% by mass or more. 30% by mass or less, and the content of the polyfunctional amine-based compound is 10% by mass or more and 40% by mass or less.

In the heat-resistant adhesive sheet of the present invention, the weight average molecular weight of the bisphenol A type epoxy compound is preferably 10,000 or more and 50,000 or less.

In the heat-resistant adhesive sheet of the present invention, the glass transition temperature (Tg) of the polyester compound is preferably from 0 ° C to 50 ° C.

In the heat-resistant adhesive sheet of the present invention, it is preferred that the resin layer is formed by applying a solution of the resin layer-forming composition onto the base film and heating the coating layer to form a cured film.

In the heat-resistant adhesive sheet of the present invention, the film thickness of the resin layer is preferably 50 nm or more and 500 nm or less.

The method for producing a functional film of the present invention comprises the steps of: including a release substrate made of a polyester film, a resin layer provided on one main surface of the release substrate, and the peeling layer; Forming the adhesive layer and the base film on the release agent layer of the release film of the release agent layer on the other main surface of the substrate, and obtaining the initial haze value of the release film at 150 ° C Heat-resistant adhesive sheet having an absolute value of the difference in haze value after heating for 2 hours after heating, having a haze value of 0.15% or less a laminating step of forming a conductive material as a functional layer on the base film of the heat-resistant adhesive sheet; and heat-treating the heat-resistant adhesive sheet having the functional layer formed thereon step.

According to this method, since the back side of the functional layer provided on the base film is protected by the release film including the release substrate, the resin layer and the release agent layer, the adhesion protection function layer can be omitted in the production of the functional film. The step of protecting the sheet on the back side. Therefore, it is possible to realize a heat-resistant adhesive sheet which can reduce the manufacturing cost of the functional film by shortening the manufacturing steps.

In the method for producing a functional film of the present invention, it is preferred that the functional layer be a transparent conductive layer.

According to the present invention, it is possible to provide a heat-resistant adhesive sheet and a method for producing a functional film which are excellent in heat resistance and which can reduce the manufacturing cost of the functional film by shortening the production steps.

1, 2‧‧‧ heat-resistant adhesive sheets

3‧‧‧Layer

10‧‧‧Release film

11‧‧‧ peeling substrate

12‧‧‧ resin layer

13‧‧‧ Stripper layer

14‧‧‧Adhesive layer

141‧‧‧ core material

142‧‧‧First adhesive layer

143‧‧‧Second Adhesive Layer

21‧‧‧Substrate film

22‧‧‧ functional layer

Fig. 1 is a schematic cross-sectional view showing a heat-resistant adhesive sheet according to an embodiment of the present invention.

Figure 2 is a schematic cross-sectional view showing a laminate according to an embodiment of the present invention.

Figure 3 is a view showing a heat-resistant adhesive sheet according to an embodiment of the present invention. A schematic cross-sectional view of another example.

Fig. 4A is an explanatory view showing a method of producing a functional film according to an embodiment of the present invention.

Fig. 4B is an explanatory view showing a method of producing a functional film according to an embodiment of the present invention.

Fig. 4C is an explanatory view showing a method of producing a functional film according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to additional drawings. Further, the present invention is not limited to the following embodiments, and can be implemented as appropriate. In the following embodiments, the same components are denoted by the same reference numerals, and the description thereof will not be repeated.

Fig. 1 is a schematic cross-sectional view showing a heat-resistant adhesive sheet 1 according to an embodiment of the present invention. As shown in Fig. 1, the heat-resistant adhesive sheet 1 of the present embodiment includes a release film 10 having a release substrate 11 made of a polyester film and a resin layer provided on one main surface of the release substrate 11. A resin layer 12 obtained by curing the composition and a release agent layer 13 which is formed on the other main surface of the release substrate 11 and which is obtained by curing the composition for forming a release layer are formed. The base film 21 is laminated on the release agent layer 13 of the release film 10 through the adhesive layer 14. That is, in the heat-resistant adhesive sheet 1, the resin layer 12, the release substrate 11, the release agent layer 13, the adhesive layer 14, and the base film 21 are laminated in this order.

On the substrate film 21, it is provided as a functional layer 22 Conductive layers, etc. (refer to Figure 2). The heat-resistant adhesive sheet 1 of the present embodiment is formed by forming a transparent conductive material-providing functional layer 22 on the base film 21 to form a laminate 3, and then forming a transparent conductive layer by annealing by heating in the state of the laminate 3. Further, as the functional layer 22, for example, a transparent conductive layer is exemplified, but it is not limited thereto.

The heat-resistant adhesive sheet 1 of the present embodiment can be wound up in a roll shape on a core material and stored. The adhesive sheet 1 is wound up in a roll-like state and subjected to a specific heat treatment, for example, and then the release film 10 is removed, and the exposed surface of the adhesive layer 14 is attached to the adherend to be used for manufacture of various products. . As the adherend, for example, a glass substrate is exemplified. As the specific heat treatment, various heat treatments can be carried out within the range in which the effects of the present invention are exerted, and for example, an annealing treatment for crystallizing the transparent conductive material is exemplified.

The heat-resistant adhesive sheet 1 of the present embodiment can be used for producing a transparent conductive film for a touch panel or the like by, for example, forming a transparent conductive material as the functional layer 22 and then performing annealing treatment by heating. In the heat-resistant adhesive sheet 1, the absolute haze value of the difference between the initial haze value of the release film 10 and the post-heating haze value after heating at 150 ° C for 2 hours is 0.15% or less. Therefore, even if the transparent conductive layer as the functional layer 22 is provided on the heat-resistant adhesive sheet 1 and the annealing treatment is performed by heating, since the change in the haze value of the release film before and after the annealing treatment is sufficiently small, the transparent setting can be made transparent. The heat-resistant adhesive sheet 1 of the conductive layer is subjected to an annealing treatment in a state in which the adhesive layer 14 is provided. Further, the back side of the functional layer 22 (one side of the heat-resistant adhesive sheet 1) is peeled off through the adhesive layer 14. Since the film 10 is used, the release film 10 can also function as a protective sheet attached to the back surface of the transparent conductive film of the prior art, so that the manufacturing process of the transparent conductive film can be shortened to reduce the cost. Further, since the resin layer 12 is provided on the back side of the functional layer 22 with a composition of a specific resin layer, it is possible to prevent the oligomer from being deposited on one side of the heat-resistant adhesive sheet 4 even if a film forming function layer is formed. In the state of 22, when the core material is wound into a roll shape, although the polyester film is used as the release substrate 11, the surface contamination and damage of the functional layer 22 can be prevented.

Fig. 3 is a schematic cross-sectional view showing another configuration example of the heat-resistant adhesive sheet 1 according to the embodiment of the present invention. The adhesive layer 14 of the heat-resistant adhesive sheet 2 of the heat-resistant adhesive sheet 2 includes a core material 141, a first adhesive layer 142 provided on one surface of the core material 141, and another one of the core materials 141. The second adhesive layer 143 on the surface. As the core material 141, for example, various films such as a polyester film similar to the release base material 11, paper, nonwoven fabric, and the like can be used. The first adhesive layer 142 and the second adhesive layer 143 are made of the same material as the adhesive layer 14. According to this configuration, the same effects as those of the heat-resistant adhesive sheet 1 shown in Fig. 1 described above can be obtained. Hereinafter, various constituent elements constituting the heat-resistant adhesive sheets 1 and 2 of the present embodiment will be described.

(release substrate 11)

As the release substrate 11, various polyester films can be used. The polyester film is excellent in heat resistance, and does not cause defects such as shrinkage and melting even when the transparent electrode layer such as a transparent conductive film is annealed at a high temperature. Polyester thin The film is preferably a polyester film such as polyethylene terephthalate, polybutylene terephthalate or polyethylene naphthalate. Further, the polyester film is more preferably a biaxially stretched polyethylene terephthalate film.

The thickness of the release substrate 11 can be appropriately changed depending on the application. The thickness of the release substrate 11 is preferably 10 μm or more, more preferably 20 μm or more, from the viewpoint of maintaining the strength of the heat-resistant adhesive sheet and the flexibility when the transparent conductive film is produced by a roll-to-roll. It is 30 μm or more, and preferably 250 μm or less, more preferably 225 μm or less, and still more preferably 200 μm or less. In consideration of the above, the thickness of the release substrate 11 is preferably from 10 μm to 250 μm, more preferably from 20 μm to 225 μm, still more preferably from 30 μm to 200 μm.

(resin layer 12)

The resin layer 12 preferably contains (A) a bisphenol A type epoxy compound (hereinafter also referred to simply as "(A) component") and (B) polyester, from the viewpoint of preventing precipitation of the oligomer from the release substrate 11 . A hardened film obtained by curing a compound (hereinafter referred to as "(B) component)" and (C) a polyfunctional amine-based compound (hereinafter also referred to as "(C) component"). Hereinafter, each component constituting the composition for forming a resin layer will be described in detail.

<(A) Bisphenol A type epoxy compound>

The (A) bisphenol A type epoxy compound can be exemplified by a bisphenol A type epoxy resin such as a copolymer of bisphenol A and epichlorohydrin.

(A) is based on a hardened skin that achieves a moderate crosslink density From the viewpoint of the film, the weight average molecular weight (Mw) is preferably from 10,000 to 50,000. When the weight average molecular weight (Mw) of the component (A) is 10,000 or more, it is possible to obtain a sufficient crosslinking density as a cured film to sufficiently prevent the oligomer from being precipitated. In addition, when the weight average molecular weight (Mw) of the component (A) is 50,000 or less, appropriate flexibility can be imparted to the cured film, and cracking of the resin layer 12 when the heat-resistant adhesive sheet 1 is deformed can be prevented.

The amount of the component (A) in the resin layer-forming composition is preferably 50% by mass or more, more preferably 60% by mass or more, and preferably 80% by mass or less based on the total mass of the resin layer-forming composition. More preferably, it is 70% by mass or less.

<(B) Polyester Compound>

As the (B) polyester compound, various conventional polyester compounds can be used within the range in which the effects of the present invention are exerted. The polyester compound is exemplified by a resin obtained by, for example, a condensation reaction of a polyhydric alcohol and a polybasic acid. Such a resin is exemplified by a condensate of a dibasic acid and a glycol or a non-converting polyester compound in which a condensate is modified with a non-drying oil fatty acid, and a conversion property of a condensate of a dibasic acid and a trihydric or higher alcohol. Polyester compounds, etc. The polyester compound may be used alone or in combination of two or more.

Examples of the polyhydric alcohol include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethyl glycol, tetramethyl glycol, and neopentyl glycol, glycerin, and trimethylolethane. And a tetrahydric or higher polyhydric alcohol such as triol, triglycerin, triglycerin, pentaerythritol, dipentaerythritol, mannitol or sorbitol such as trimethylolpropane. These polyols can be used alone One type can also be used in combination of two or more types.

Examples of the polybasic acid include aromatic polybasic acids such as phthalic anhydride, terephthalic acid, isophthalic acid, and trimellitic anhydride, and aliphatic saturated polybasic acids such as succinic acid, adipic acid, and sebacic acid. Aliphatic unsaturated polybasic acids such as acid, maleic anhydride, fumaric acid, isaconic acid and citraconic acid, dicyclopentadiene-maleic anhydride adducts, terpine-maleic anhydride adducts, And a polybasic acid obtained by a Diels-Alder reaction, such as a rosin-maleic anhydride adduct. These polybasic acids may be used alone or in combination of two or more.

The (B) polyester compound is preferably an active hydrogen having a hydroxyl group, a carboxyl group or an amine group which is a reaction point of the crosslinking reaction, and more preferably has a hydroxyl group. The hydroxyl value of the (B) polyester compound is preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more, and is preferably 500 mgKOH/g or less, more preferably 300 mgKOH/g or less.

(B) The polyester compound has a number average molecular weight (Mn) of preferably 500 or more, more preferably 1,000 or more, and more preferably 10,000 or less, more preferably 5,000 or less, from the viewpoint of imparting moderate flexibility to the resin layer 12. (B) The polyester compound has a glass transition temperature Tg of preferably 0 ° C or more, more preferably 10 ° C or more, and more preferably 50 ° C or less, more preferably 40 ° C, from the viewpoint of imparting moderate flexibility to the resin layer 12 . the following. By using such a (B) polyester compound, moderate softness can be imparted to the hardened film of the resin layer 12, and even if the heat-resistant adhesive sheet 1 is subjected to pressure or impact, the resin layer 12 can be prevented from being cracked, and the oligomer can be prevented from being caused. Cracked and leaked out.

The amount of the component (B) in the composition for forming a resin layer is relatively The amount of the component (A) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 50 parts by mass or less, more preferably 45 parts by mass or less.

The amount of the component (B) in the resin layer-forming composition is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 30% by mass or less, based on the total mass of the resin layer-forming composition. More preferably, it is 20% by mass or less.

<(C) Polyfunctional Amine Compound>

Examples of the (C) polyfunctional amine-based compound include a melamine compound such as hexamethoxymethyl melamine, a methylated melamine compound, and a butylated melamine compound, a methylated urea compound, and a butylated urea compound. Benzofluorene compounds such as urea compounds, methylated benzofluorene resins and butylated benzofluorene compounds, ethylenediamine, tetramethylenediamine, hexamethylenediamine, N,N'-diphenyl Examples of the diamines such as ethylenediamine and p-xylenediamine are hexamethoxymethylmelamine from the viewpoint of curability.

The amount of the component (C) in the resin layer-forming composition is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and preferably 60 parts by mass or less, more preferably 100 parts by mass or more based on 100 parts by mass of the component (A). It is 55 parts by mass or less.

The amount of the component (C) in the resin layer-forming composition is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 40% by mass or less, based on the total mass of the resin layer-forming composition. Better for 30% by mass or less.

<(D) Acid Catalyst>

In order to promote the curing reaction, a conventional acid catalyst (D) containing hydrochloric acid, p-toluenesulfonic acid or the like (hereinafter also referred to simply as "(D) component") may be used as the resin layer-forming composition. When the component (D) is blended, the content of the component (D) is preferably from 1% by mass to 5% by mass based on the total mass of the resin layer-forming composition.

The resin layer 12 is applied onto the release substrate 11 by applying a solution obtained by dissolving the above resin layer-forming composition in an organic solvent to form a coating layer, and the formed coating layer is heat-hardened at a temperature of 100° C. or higher and 170° C. or lower. Obtained in less than 5 minutes in seconds. Examples of the coating method of the resin layer-forming composition are, for example, a gravure coating method, a bar coating method, a spray coating method, a spin coating method, an air knife coating method, a roll coating method, a blade coating method, and the like. Brake roll coating method and die coating method. Among these, a gravure coating method and a bar coating method are preferred, and a bar coating method is more preferred. Further, the heating/drying method of the resin layer-forming composition is exemplified by a thermal drying method such as a hot air drying furnace or the like.

The organic solvent is not particularly limited as long as it is a composition for dissolving a resin layer. The organic solvent is exemplified by an aromatic solvent such as benzene, toluene or xylene, an aliphatic solvent such as n-hexane or n-heptane, an ester solvent such as ethyl acetate or butyl acetate, or methyl ethyl ketone. A ketone solvent such as methyl isobutyl ketone, cyclohexanone or cycloheptanone; an alcohol solvent such as isopropyl alcohol or methanol;

The film thickness of the resin layer 12 is preferably 50 nm or more, more preferably 80 nm or more, still more preferably 100 nm or more, and more preferably 500 nm or less, more preferably 300 nm or less, from the viewpoint of effectively suppressing the precipitation of the oligomer. More preferably below 250 nm. When the film thickness of the resin layer 12 is 50 nm or more, the oligomer deposition can be sufficiently suppressed, and when it is 500 nm or less, the crosslinking of the resin layer 12 when the resin layer 12 is formed on the release substrate 11 can be prevented. Curl caused by hardening shrinkage. In consideration of the above, the film thickness of the resin layer 12 is preferably 50 nm or more and 500 nm or less, more preferably 80 nm or more and 300 nm or less, and still more preferably 100 nm or more and 250 nm or less.

(release agent layer 13)

The release agent layer 13 is formed, for example, as a cured product of a release agent layer-forming composition containing a release agent. The release agent layer-forming composition is not particularly limited as long as the release agent layer 13 is provided with the adhesive layer 14 which is peeled off from the release agent layer 13 and laminated on the release agent layer 13. The release agent is exemplified by a polyoxymethylene resin, a long-chain alkyl resin, an alkyd resin, and the like.

Examples of the polyfluorene oxygen release agent include addition reaction type polyoxane, condensation reaction type polyoxane, and energy ray-curable polyfluorene. Further, in order to adjust the peeling force, a non-functional polydimethyl siloxane, a phenyl-modified polyfluorene oxide, a polyoxyn epoxide, a cerium oxide, or a cellulose-based compound may be used as an additive.

The thickness of the release agent layer 13 is preferably 30 nm or more, preferably 50 nm or more, more preferably 70 nm or more, and preferably 500 nm. Next, it is preferably 400 nm or less, and more preferably 300 nm or less. If the thickness of the release agent layer 13 is within this range, uniform release property is easily obtained between the release film 10 and the adhesive layer 14, and the release film which is contacted when the release film 10 is wound into a roll shape can be prevented. The faces of 10 are glued to each other.

The release agent layer 13 is formed by applying a composition for forming a release agent layer on one surface of the release substrate 11 by a coating method conventionally known in the art, and then heating, drying, and hardening at a specific temperature. Here, the release agent layer-forming composition may be applied to the release substrate 11 by dilution with an organic solvent. Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene, aliphatic esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and hexane and heptane. Such as aliphatic hydrocarbons and the like.

Examples of the coating method for forming the release agent layer are, for example, a gravure coating method, a bar coating method, a spray coating method, a spin coating method, an air knife coating method, a roll coating method, and a blade coating method. , brake roll coating method and die coating method. Among these, a gravure coating method and a bar coating method are preferred, and a bar coating method is more preferred. Further, the heating/drying method of the composition for forming a release agent layer is exemplified by a thermal drying method such as a hot air drying furnace or the like. The drying temperature is, for example, 50 ° C or more and 150 ° C or less. The drying time is preferably, for example, 10 seconds to 5 minutes.

(release film 10)

The release film 10 is formed by laminating the above-mentioned resin layer 12, release base material 11, and release agent layer 13 in this order. The thickness of the release film 10 is preferably, for example, 10 μm or more, preferably 15 μm or more, and more preferably 200 μm. Next, it is preferably 100 μm or less.

(adhesive layer 14)

In the heat-resistant adhesive sheet 1 of the present embodiment, the pressure-sensitive adhesive layer 14 is heat-treated while being sandwiched between the release substrate 11 and the base film 21. Since the heat treatment is exposed to a high temperature by the adhesive which initially constitutes the adhesive layer 14, if the general adhesive having low heat resistance is used, the viscosity of the adhesive layer 14 from the adhesive is lowered to cause the base film 21 and the release film 10 to be removed. The phenomenon of the phenomenon of end leakage. When the viscosity of the adhesive is lowered, the adhesive layer 14 which oozes out the end portions of the base film 21 and the release film 10 is transferred and adhered to the object contacted by the adhesive to contaminate the contacted articles (for example, the transfer roller of the annealing treatment device and Surface contamination caused by re-adhesion of heat-resistant adhesive sheets).

Therefore, in the present embodiment, as the adhesive layer 14, the storage elastic modulus (G) at 23 ° C is higher than the viewpoint of improving the heat resistance during the heat treatment of the adhesive layer 14 and the subsequent durability. It is preferably 0.3 MPa or more, more preferably 0.35 MPa, and more preferably 50 MPa or less, more preferably 15 MPa or less, and still more preferably 12 MPa or less. Further, in the present embodiment, an elastic modulus (G) is used to laminate an adhesive having a thickness of 30 μm, and 8 mm is produced. A cylindrical test piece having a thickness of 3 mm was measured by a torsional shear method under the following conditions.

Measuring device: Dynamic viscoelasticity measuring device (Model: DYNAMIC ANALYZER RDAII, manufactured by Rheometric)

Frequency: 1Hz

Temperature: 23 ° C, 80 ° C

Further, the adhesive layer 14 is preferably a gel fraction of 85% or more based on the viewpoint of heat resistance, durability, and stability of the adhesive layer 14 and prevention of contamination of the adherend by the adhesive. More preferably 90 or more and 99.9% or less.

The adhesive layer 14 is an acrylic adhesive, a natural rubber adhesive, a synthetic rubber adhesive, a polyether adhesive, a polyester adhesive, a urethane adhesive, and a urethane acrylate. It is formed by a conventional composition for forming an adhesive layer such as an ester-based adhesive. The acrylic adhesive is exemplified by, for example, a composition for forming an adhesive layer containing an acrylic polymer. The adhesive is supplied in the form of a solvent type, an emulsion type, a hot melt solventless type, and an ultraviolet curable solventless type, and the adhesive layer 14 is formed by a coating method in each form.

<Acrylic polymer>

The acrylic polymer is obtained by polymerizing a (meth) acrylate, a vinyl monomer containing a reactive group such as a hydroxyl group or a carboxyl group, and a monomer containing an aromatic monomer or the like.

The (meth) acrylate is exemplified by, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate Ester, isobutyl (meth)acrylate, second butyl (meth)acrylate, tert-butyl (meth)acrylate, n-amyl (meth)acrylate, n-hexyl (meth)acrylate, (a) Base) cyclohexyl acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, An alkyl group of an ester moiety such as decyl (meth)acrylate, dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate The alkyl (meth)acrylate having a carbon number of 1 or more and 20 or less. Here, "(meth)acrylic acid" means "acrylic acid" or "methacrylic acid". These acrylic monomers may be used alone or in combination of two or more.

The vinyl monomer having a reactive functional group is exemplified by a hydroxyl group-containing (meth)acrylic acid such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate or hydroxybutyl (meth)acrylate. Ester; 1,4-bis(methyl)propenyloxyethyl pyromellitic acid, 4-(methyl)propenyloxyethyl trimellitic acid, N-(methyl)acryloxycarbonyl- a carboxyl group containing p-aminobenzoic acid, 2-(meth)acryloxybenzoic acid, N-(methyl)propenyloxy-5-aminosalicylic acid, acrylic acid, methacrylic acid or the like ( Methyl)acrylate; aminoethyl (meth)acrylate, ethylaminoethyl (meth)acrylate, aminopropyl (meth)acrylate, ethylaminopropyl (meth)acrylate, etc. A thiol group-containing (meth) acrylate such as a 1st and 2nd amino group; a thiol group-containing (meth) acrylate such as 2-(methylthio)ethyl methacrylate; These may be used alone or in combination of two or more.

The content of the constituent unit derived from the vinyl monomer having a reactive functional group in the acrylic polymer is preferably 0.01 mol% or more, more preferably 0.1 mol% or more, and more preferably 20 mol% or less. More preferably 10% or less.

As the aromatic monomer, from the viewpoint of increasing the refractive index of the adhesive layer 14, it is preferred that the homopolymer exhibit a glass transition temperature of 50 ° C or less. High refractive index acrylic monomer.

Examples of the aromatic monomer are, for example, phenoxyethyl (meth)acrylate, 2-(1-naphthalenyloxy)-1-ethyl (meth)acrylate, and 2-(2-(2-)(meth)acrylate. Naphthyloxy)-1-ethyl ester, 6-(1-naphthalenyloxy)-1-hexyl (meth)acrylate, 6-(2-naphthyloxy)-1-hexyl (meth)acrylate , 8-(1-naphthalenyloxy)-1-octyl (meth)acrylate, 8-(2-naphthalenyloxy)-1-octyl (meth)acrylate, 2-(meth)acrylate Phenylthio-1-ethyl ester, 6-(4,6-dibromo-2-isopropylphenoxy)-1-hexyl (meth)acrylate, 6-(4, (meth)acrylic acid 6-Dibromo-2-t-butylphenoxy)-1-hexyl ester, 2,6-dibromo-4-decylphenyl (meth)acrylate and 2,6-(meth)acrylate Dibromo-4-dodecylphenyl ester and the like.

The composition for forming an adhesive layer preferably contains an acrylic triblock copolymer. The acrylic triblock copolymer is preferably represented by the following formula (1) and has a weight average molecular weight (Mw) of 50,000 or more and 300,000 or less, and a molecular weight distribution (Mw/Mn) of 1.0 to 1.5. The content is 50% by mass or more and 95% by mass or less.

A1-B-A2... Formula (1) (In the formula (1), A1 and A2 each independently represent an alkyl methacrylate polymer block having a glass transition temperature of 100 ° C or higher, and B represents a glass transition temperature of Alkyl acrylate polymer block below -20 ° C).

In the acrylic triblock copolymer represented by the above formula (1), the polymer blocks A1 and A2 are used as an adhesive in the acrylic triblock copolymer which is a microphase separation structure at a usual use temperature. The role of the phase (physical quasi-crosslinking point). Thereby, even if chemical crosslinking is not carried out, It exhibits sufficient agglutination and exhibits excellent adhesion characteristics and durability. The polymer blocks A1 and A2 in the acrylic triblock copolymer represented by the above formula (1) are based on durability, heat resistance, followability to substrate deformation, and moderate stress relaxation. The transition temperature is preferably from 100 ° C to 200 ° C, more preferably from 100 ° C to 150 ° C. Further, as A1 and A2, it may be a polymer [molecular weight, monomer composition, stereo structure (such as a syndiotactic) or the like, which are the same as the same alkyl methacrylate polymer], and may also be different polymers [molecular weight, single One or two or more kinds of alkyl methacrylate polymers different in body composition, three-dimensional structure (and syndiotactic, etc.).

The alkyl methacrylate unit as the polymer blocks A1 and A2 can be exemplified by, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, and methacrylic acid. Butyl ester, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, dodecyl methacrylate, methacrylic acid A unit made of an alkyl methacrylate such as stearyl ester or isobornyl methacrylate. The polymer blocks A1 and A2 may be formed of only one of the above-mentioned alkyl methacrylate units, or may be formed of two or more types. Among these, the polymer blocks A1 and A2 are preferably composed of a unit of methyl methacrylate, from the viewpoint of availability, durability, and weather resistance.

The polymer block B is preferably a polymer block having a glass transition temperature of -20 ° C or less, which is formed of an alkyl acrylate, from the viewpoint of adhesion and rework of the adhesive layer 14 . As a polymer embedded From the viewpoint of the stability under low temperature conditions, the segment B is more preferably a polymer block having a glass transition temperature of -30 ° C or less, and more preferably a polymer block of -80 ° C or more and -40 ° C or less.

The polymer block B can be exemplified by, for example, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate. A unit made of an alkyl acrylate such as n-octyl acrylate, lauryl acrylate, dodecyl acrylate or stearyl acrylate. The polymer block B may be formed of only one of the above alkyl acrylate units, or may be formed of two or more types. In the above, the polymer block B is based on the viewpoint that the adhesion of the glass block of the polymer block to an adhesive of -20 ° C or lower and the adhesion at low temperature are good, and the high-speed peeling can be suppressed. Further, from the viewpoint of the force increase and the zipping phenomenon, it is preferably one or more selected from the group consisting of propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and n-octyl acrylate. Further, the polymer block B is not broken due to the ease of obtaining and the phase separation of the polymer blocks A1, A2 and the polymer block B, and the pseudo-crosslinking point of the polymer block A does not collapse, and is used as an adhesive. The viewpoint of high cohesive force and excellent durability is preferably composed of n-butyl acrylate unit and/or 2-ethylhexyl acrylate unit.

The polymer blocks A1, A2 and the polymer block B in the acrylic triblock copolymer represented by the above formula (1) are small in the range in which the effects of the present invention are exerted (for example, usually relative to each polymerization) The mass of the block is 10% by mass or less, and may have other monomer units. As other monomer units, for example, methoxyethyl (meth)acrylate Ester, ethoxyethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-aminoethyl (meth)acrylate, (A) a (meth) acrylate having a functional group such as glycidyl acrylate and tetrahydrofurfuryl (meth) acrylate, (meth)acrylic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, and A vinyl monomer having a carboxyl group such as (meth)acrylamide, an aromatic vinyl monomer such as styrene, α-methylstyrene or p-methylstyrene, butadiene and isoprene The conjugated diene monomer, such as an olefin monomer such as ethylene or propylene, or a lactone monomer such as ε-caprolactone or valerolactone. These monomer units may be contained alone or in combination of two or more.

The polymerization method of the acrylic polymer is not particularly limited, and it can be polymerized by a general radical polymerization method. Examples of the radical polymerization method include solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization.

The molecular weight of the acrylic polymer is preferably from 500,000 or more, more preferably 600,000 or more, and more preferably 700,000 or more, from the viewpoint of heat resistance. The larger the weight average molecular weight of the acrylic polymer, the more the interlacing of the molecular chains, the lower the flow at high temperatures and the higher the heat resistance. Further, the weight average molecular weight of the acrylic polymer is preferably 2,000,000 or less, more preferably 1.8,000,000 or less, from the viewpoint of coatability or adhesion to an adherend. When the upper limit of the weight average molecular weight of the acrylic polymer is such an extent, it can be applied without excessively diluting the composition for forming an adhesive layer, and the fluidity is not excessively insufficient, so that the adhesive layer can follow the adherend. Surface roughness ensures adhesion. Further, the above weight average molecular weight is determined by a gel permeation chromatography (GPC) method. The value of polystyrene conversion.

<Active energy ray-curable compound>

Moreover, it is preferable that the composition for forming an adhesive layer contains an active energy ray-curable compound from the viewpoint of improving the elastic modulus and the gel fraction of the adhesive layer 14. The active energy ray-curable compound is exemplified by, for example, a polyfunctional (meth) acrylate monomer having a molecular weight of less than 1,000, an acrylate oligomer, and an addition of a group having a (meth) acrylonitrile group introduced into a side chain. An acrylate polymer or the like.

As the polyfunctional (meth)acrylate monomer having a molecular weight of less than 1,000, for example, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate , neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol (Meth) acrylate, dicyclopentyl di(meth) acrylate, caprolactone modified dicyclopentenyl di(meth) acrylate, ethylene oxide modified bis(methyl) a bifunctional type such as acrylate, bis(acryloxyethyl)isocyanurate, and allylated cyclohexyl di(meth)acrylate, trimethylolpropane tri(meth)acrylic acid Ester, dipentaerythritol tri(meth) acrylate, propionic acid modified dipentaerythritol tri(meth) acrylate, pentaerythritol tri(meth) acrylate, propylene oxide modified trimethylolpropane tris a trifunctional type such as acrylate or ginseng (propylene oxyethyl) isocyanurate, a tetrafunctional type such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate, C Acid-modified dipentaerythritol penta (meth) acrylate, etc. 5-functional, di-penta A 6-functional type such as tetraol hexa(meth) acrylate or caprolactone modified dipentaerythritol hexa(meth) acrylate. These polyfunctional (meth)acrylate monomers may be used alone or in combination of two or more.

The polyfunctional (meth)acrylate monomer preferably has a cyclic structure in the skeleton structure. The ring structure may be a carbon ring structure or a heterocyclic structure, and may have a single ring structure or a multi ring structure. Such a polyfunctional (meth) acrylate type monomer is exemplified by, for example, bis(propylene oxyethyl) isocyanurate and ginseng (propylene oxyethyl) isocyanurate. Uric acid structure builder, dimethylol dicyclopentane diacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neopentyl glycol modification Trimethylolpropane diacrylate, and adamantane diacrylate.

The acrylic oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such an acrylate-based oligomer are, for example, a polyester acrylate-based oligomer, an epoxy acrylate-based oligomer, a urethane-based oligomer, a polyether acrylate-based oligomer, and a polybutylene. A diene acrylate oligomer and a polyoxy acrylate oligomer.

The polyester acrylate-based oligomer can be obtained by, for example, esterifying a hydroxyl group of a polyester oligomer having a hydroxyl group at both terminals obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth)acrylic acid. Further, the polyester acrylate-based oligomer may be obtained by (meth)acrylating a hydroxyl group at the terminal of the oligomer obtained by adding an alkylene oxide to a polyvalent carboxylic acid.

The epoxy acrylate oligomer can be obtained, for example, by making a relatively low molecular weight bisphenol type epoxy resin or a novolac type epoxy resin The alkane is reacted with (meth)acrylic acid and esterified. Further, a carboxy-modified epoxy acrylate oligomer in which the epoxy acrylate oligomer is partially modified with a dicarboxylic acid anhydride can also be used. The urethane acrylate oligomer can be esterified with (meth)acrylic acid by, for example, reacting a polyether polyol or a polyester polyol with a polyisocyanate. Thus, the polyol acrylate oligomer can be obtained by (meth)acrylating a hydroxyl group of a polyether polyol.

The weight average molecular weight of the acrylate-based oligomer is preferably 50,000 or less, more preferably 500 or more and 50,000 or less, and still more preferably 3,000 or more and 40,000 or less in terms of a standard polymethyl methacrylate measured by a GPC method. These acrylate-based oligomers may be used alone or in combination of two or more.

The addition acrylate polymer having a (meth) acrylonitrile group introduced into the side chain can be obtained by using a copolymer of the above (meth) acrylate and a monomer having a crosslinkable functional group in the molecule. A portion of the crosslinkable functional group of the copolymer is reacted with a compound having a group reactive with a (meth) acrylonitrile group and a crosslinkable functional group. The weight average molecular weight of the addition acrylate polymer is usually 500,000 or more and 2,000,000 or less in terms of polystyrene.

<Photopolymerization initiator>

When an energy ray-curable compound is used as the composition for forming an adhesive layer, a photopolymerization initiator is used from the viewpoint of improving the modulus of elasticity of the adhesive layer 14 and the gel fraction. As an example of a photopolymerization initiator Such as benzoin, benzoin methyl ether, benzoin ether, benzoin propyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylamino acetophenone, 2, 2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one , 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinepropan-1-one, 4-(2-hydroxyethoxy)benzene 2-(hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2 -methyl hydrazine, 2-ethyl hydrazine, 2-tert-butyl hydrazine, 2-amino hydrazine, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-chlorothioxanthene Ketone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylacetal, acetophenone dimethyl acetal, p-dimethylaminobenzoic acid Ester, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propane], 2,4,6-trimethylbenzimidyldiphenylphosphine oxide Wait. These may be used alone or in combination of two or more.

The amount of the photopolymerization initiator is preferably 0.2 parts by mass or more and 20 parts by mass or less based on 100 parts by mass of the energy ray-curable compound.

<crosslinker>

The adhesive layer-forming composition preferably contains a crosslinking agent (curing agent) from the viewpoint of improving the modulus of elasticity of the adhesive layer 14 and the gel fraction. The crosslinking agent is preferably selected from the group consisting of polyfunctional isocyanate compounds such as polyfunctional amine-based compounds and polyisocyanate compounds, polyfunctional epoxy compounds, polyfunctional aziridine compounds, polyfunctional oxazoline compounds, and polyfunctional metal compounds. At least one of the group consisting of. The crosslinking agent can be used, for example The adhesive is crosslinked by reacting with a reactive functional group of the acrylic polymer. Further, as the composition for forming an adhesive layer, a curing accelerator, a hardening retarder or the like may be used.

Specific examples of the polyfunctional isocyanate compound are exemplified by 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylene diisocyanate, 1,4-dimethylbenzene diisocyanate, and diphenylmethane-4. 4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isodecyl ketone diisocyanate, dicyclohexylmethane-4, 4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate and isocyanuric acid isocyanate. Further, a trimer of the polyfunctional isocyanate compound and a terminal isocyanate urethane polymer obtained by reacting the polyfunctional isocyanate compound with a polyol compound may be used.

Specific examples of the polyfunctional epoxy compound are 1,3-bis(N,N-diglycidylaminomethyl)benzene, 1,3-bis(N,N-diglycidylaminomethyl)toluene, N , N, N', N'-tetraglycidyl-4,4-diaminodiphenylmethane, and the like.

Specific examples of the polyfunctional aziridine compound are N,N'-diphenylmethane-4,4'-bis(1-aziridine carboxamide) trimethylolpropane tris-β-aziridine Propionate, tetramethylol methane tri-β-aziridine propionate, N,N'-toluene-2,4-bis(1-aziridine carboxamide) tri-ethyl melamine Wait.

Specific examples of the polyfunctional oxazoline compound are exemplified by 2-isopropenyl-2-oxazoline and the like at the carbon position at the 2-position having an unsaturated carbon-carbon bond. A copolymer of a substituent polymerizable 2-oxazoline and another unsaturated monomer.

Specific examples of the polyfunctional metal compound are exemplified by polyvalent metals such as aluminum ethyl acetoxyacetate, ethyl acetoacetate aluminum diisopropylate, and aluminum chelating agent compounds such as aluminum acetyl acetonate. Coordination compounds, etc. Among these, an aluminum chelating agent compound is preferred from the viewpoint of obtaining sufficient adhesion.

In the composition for forming an adhesive layer, a crosslinking agent may be used alone or in combination with a plurality of different crosslinking agents. In order to improve the heat resistance of the adhesive layer, it is preferred to combine a heterogeneous crosslinking agent. Specific examples of the combination of the heterologous crosslinking agent are preferably a combination of a polyfunctional isocyanate compound and a polyfunctional epoxy compound, or a combination of a polyfunctional isocyanate compound and a polyfunctional metal compound.

The amount of the crosslinking agent is preferably 0.1 part by mass or more, more preferably 1 part by mass per 100 parts by mass of the acrylic polymer, based on the viewpoint of the adhesive layer which is excellent in adhesiveness and cohesive strength. The amount is preferably 30 parts by mass or less, more preferably 20 parts by mass or less.

<decane coupling agent>

As the composition for forming an adhesive layer, a decane coupling agent may be used as needed. When the transparent conductive film is attached to a glass substrate or the like by using the decane coupling agent, the adhesion between the adhesive layer and the glass unit is good. The decane coupling agent has at least one in the molecule The organic anthracene compound of the alkoxyalkylene group is preferably one having good compatibility with the adhesive component and having light transparency.

The decane coupling agent is exemplified by a fluorene compound containing a polymerizable unsaturated group such as vinyl trimethoxy decane, vinyl triethoxy decane, methacryloxypropyltrimethoxy decane or the like, and 3-glycidyloxygen. An anthracene compound having an epoxy group structure such as propyltrimethoxydecane or 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, 3-aminopropyltrimethoxydecane, N Amino group-containing (2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane Then a compound, 3-chloropropyltrimethoxydecane or the like. These may be used alone or in combination of two or more.

The amount of the decane coupling agent to be added is preferably 0.001 part by mass or more and 10 parts by mass or less, more preferably 0.005 part by mass or more and 5 parts by mass or less based on 100 parts by mass of the solid content of the adhesive layer-forming composition.

<Adhesive Resin>

As the composition for forming the adhesive layer, it is also possible to impart an adhesive to the resin by adjusting the adhesion, adhesion, and holding force. Examples of the adhesion-imparting resin include a rosin-based adhesion-imparting resin, a bismuth-based adhesion-imparting resin, a petroleum-based adhesion-imparting resin, and a guacin-based resin, a phenol resin, a xylene resin, and a styrene-based resin. Resin and other adhesion-imparting resins. As the rosin-based adhesive-imparting resin, for example, rosin resin, tall oil rosin, wood rosin, hydrogenated rosin, sulphur pine Aromatic, polymeric rosin, modified rosin glyceride and modified rosin pentaerythritol ester. The resin-based adhesion-imparting resin is exemplified by α-pinene, β-pinene, dipentene resin, aromatic modified resin, and phenol resin. Examples of petroleum-based adhesion-imparting resins include C5 petroleum resin, C9 petroleum resin, C5/C9 copolymerized petroleum resin, hydrogenated C5 petroleum resin, hydrogenated C9 petroleum resin, and hydrogenated C5/C9 copolymer petroleum resin. , dicyclopentadiene petroleum resin and styrene petroleum resin. These adhesion-imparting resins may be used singly or in combination of two or more. Among these, based on the high compatibility with the acrylic triblock copolymer and the ability to exhibit a stable adhesion, it is preferred to use a resin such as a hydrogenated terpene resin or a terpene phenol, a hydrogenated rosin ester, or a hydrazine ester. A rosin-based resin such as a rosin ester or a polymerized rosin, a petroleum resin such as a C5/C9 petroleum resin or an aromatic petroleum resin, an α-methylstyrene polymer, and a styrene/α-methylstyrene copolymer. Adhesion to a resin such as a styrene resin. These may be used singly or in combination of two or more. The adhesion imparts a softening point to the resin, and in order to exhibit a high adhesion, it is preferably 50 ° C or more and 150 ° C or less.

The amount of the adhesion-imparting resin in the composition for forming an adhesive layer is preferably 0.5 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of the acrylic polymer, from the viewpoint of improving the adhesion of the pressure-sensitive adhesive layer 14 . More preferably, it is 1 part by mass or more and 50 parts by mass or less.

<UV absorber>

The composition for forming an adhesive layer is preferably one containing an ultraviolet absorber. The color of the heat-resistant adhesive sheet 1 can be protected by the ultraviolet absorber Adjust the pigment used in adjustment, etc., from UV light.

Examples of the ultraviolet absorber include, for example, a benzophenone-based compound, a benzotriazole-based compound, and a triazine-based compound. These ultraviolet absorbers may be used alone or in combination of two or more.

<rust inhibitor>

As a composition for forming an adhesive layer, it is preferable to contain a rust preventive agent. When the obtained adhesive layer 14 is brought into contact with a metal electrode or the like by containing a rust preventive agent, the change in transmittance due to the interaction between the metal and the additive and the interaction between the metal and the adhesive can be reduced.

The rust inhibitor is, for example, an azole compound having a hydroxyl group, a triazole compound, a benzotriazole compound, a thiazole compound, a benzothiazole compound, an imidazole compound, a benzimidazole compound, a phosphorus compound, or an amine. The compound, the nitrite-based compound, the surfactant, the decane coupling agent, and the like are preferable, and the benzotriazole-based rust inhibitor is preferred from the viewpoint of corrosion prevention performance. Further, the rust inhibitor may be used singly or in combination of two or more.

Examples of the benzotriazole-based rust inhibitor are, for example, 1H benzotriazole, nitrobenzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole And 1-[N,N-bis(2-ethylhexyl)aminomethyl]methylbenzotriazole and the like.

The blending amount of the rust preventive agent in the composition for forming an adhesive layer is based on the viewpoint of obtaining the effect of the rust preventive agent and the viewpoint of adhesion, and the total mass of the solid component of the composition for forming an adhesive layer is It is preferably 0.1% by mass or more and 5% by mass or less, more preferably 0.3% by mass or more and 2% by mass or less.

The thickness of the adhesive layer 14 is not particularly limited as long as it exhibits the effects of the present invention, and is, for example, preferably 3 μm or more, more preferably 10 μm or more, still more preferably 20 μm or more, and more preferably 500 μm or less, more preferably It is 400 μm or less, and more preferably 300 μm or less.

When the adhesive layer 14 is composed of the first adhesive layer 142, the second adhesive layer 143, and the core material 141, the thickness of the core material 141 is preferably 2 μm or more, more preferably 5 μm or more, and preferably 50 μm or less. More preferably 45 μm or less. The thickness of the first adhesive layer 142 and the second adhesive layer 143 is preferably 1 μm or more, and preferably 50 μm or less.

(Substrate film 21)

As the base film 21, those having heat resistance can be appropriately selected from the plastic film. As such a plastic film, a polyester film such as polyethylene terephthalate (PET), polybutylene terephthalate or polyethylene naphthalate (PEN), a polyethylene film, or the like can be used. Polypropylene film, cerium, diethyl phthalocyanine film, triethylene fluorene cellulose film, acetonitrile cellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, Ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polyfluorene film, polyetheretherketone film, polyether fluorene film, polyether quinone film, polyfluorene A plastic film such as an imine film, a fluororesin film, a polyamide film, an acrylic resin film, a film of a flavonoid resin film, and a cycloolefin resin film. In these, From the viewpoint of being excellent as a substrate for optics and excellent in transparency, a polyester film, a polycarbonate film, a polyimide film, a norbornene resin film, and a cycloolefin resin film are preferable. Better for polyester film.

The substrate film 21 may be provided with a layer that adds various functions to the surface of the plastic film. The base film 21 may have an easy-adhesive layer for reinforcing the layers, for example, on the side in contact with the functional layer 22 or the adhesive layer 14, or on the side in contact with the functional layer 22. There is a hard coating.

The thickness of the base film 21 is preferably 25 μm or more, preferably 30 μm or more, more preferably 35 μm or more, and is preferably 250 μm or less, more preferably 225 μm or less, and still more preferably 200 μm or less. In consideration of the above, the thickness of the base film 21 is preferably 25 μm or more and 250 μm or less, more preferably 30 μm or more and 225 μm or less, and still more preferably 35 μm or more and 200 μm or less.

Further, in FIG. 1, the base film 21 is shown as a single layer, but the base film 21 is not limited to being composed of a single layer. The base film 21 may be, for example, a two-layer film obtained by laminating a base film and a release agent layer, or may be configured as a three-layer film similarly to the release film 10.

<Oligomer Sealability>

The inventors of the present invention have focused on the evaluation of the haze of the heat-resistant adhesive sheet in the evaluation of the oligomer precipitation which is only visually evaluated for the appearance of the prior art. The degree of oligomer precipitation can be quantitatively evaluated. Therefore, the present inventors quantitatively evaluated the precipitation of the oligomer by measuring the haze value of the heat-resistant adhesive sheet, and found that the damage of the transparent electrode layer or the incorporation of foreign matter can be effectively prevented.

In the heat-resistant adhesive sheet 1 of the present embodiment, the oligomer of the release film 10 is atomized to atomize the release substrate 11 (polyester film) to change the haze value of the release film 10. Therefore, in the present embodiment, the resin can be confirmed by measuring the Δ haze value of the absolute value of the difference between the initial haze value of the release film 10 and the post-heating haze value of the release film 10 after heating at 150 ° C for 2 hours. The oligomer of layer 12 is hermetically sealed. However, in order to eliminate the influence of the base film 21 removed during heating (at the time of annealing treatment), the initial haze value and the haze value after heating are measured by removing the base film 21 and the release film 10 and the adhesive layer 14 Determined in the state of the laminate.

In the present embodiment, since the resin layer 12 is formed by using the above-described composition for forming a resin layer, the composition of the components (A) to (C) is set to a suitable range for preventing the oligomer from being deposited from the release substrate 10. The haze value is 0.15% or less. In addition, the initial haze value of the heat-resistant adhesive sheet 1 is a haze value before the heat-resistant adhesive sheet 1 is heated at 150 ° C for 2 hours. The haze value is preferably 0.1% or less, more preferably 0.08% or less, still more preferably 0.04% or less.

Further, in the present embodiment, the Δ haze value can be calculated as follows. First, the initial haze value (%) of the heat-resistant adhesive sheet 1 (the average value of N = 5) was measured in accordance with JIS K7105 using a haze meter (trade name: NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.). Secondly, the heat-resistant adhesive sheet 1 After hanging in a dryer at 150 ° C and heating for 2 hours, the haze value (%) after heating (the average value of N = 5) was measured in accordance with JIS K7105. Then, the absolute value of the value obtained by subtracting the initial haze value from the haze value after heating is taken as the Δ haze value.

<Use>

The heat-resistant adhesive sheet 1 of the above-described embodiment can be preferably used as a raw material film for bonding a transparent conductive film and a glass substrate, for example, in a capacitive touch panel manufacturing step. The heat-resistant adhesive film 1 is used for forming an indium oxide, zinc oxide, tin oxide, indium-tin composite oxide, tin-bismuth composite oxide, zinc-aluminum on the adhesive layer 14 during the production of a transparent conductive film. A transparent conductive material such as a composite oxide or an indium-zinc composite oxide is provided as a transparent conductive layer of the functional layer 22. The thickness of the transparent conductive layer is preferably 4 nm or more, preferably 5 nm or more, more preferably 10 nm or more, and preferably 800 nm or less, from the viewpoint of continuous film formation and stable conductivity, and from the viewpoint of obtaining sufficient transparency. More preferably, it is 500 nm or less, and more preferably 100 nm or less.

In the heat-resistant adhesive sheet 1 of the present embodiment, the Δ haze value of the absolute value of the difference between the initial haze value of the release film 10 and the post-heating haze value after heating at 150 ° C for 2 hours is 0.15% or less. Even when the transparent conductive layer is provided and the annealing treatment is performed, the change in the haze value of the release film before and after the annealing treatment can be reduced, and the heat-resistant adhesive sheet 1 provided with the transparent conductive layer can be annealed in the state in which the adhesive layer 14 is provided. deal with. Furthermore, in the annealing treatment step of the transparent conductive film, the heat resistant adhesive Since the release film 10 of the sheet 1 functions as a protective sheet, it can be preferably used even if annealing treatment is performed at a temperature of about 150 ° C at which the oligomer deposition is a problem. Further, in the heat-resistant adhesive sheet 1 of the present embodiment, in the annealing treatment or other heat treatment, it is possible to suppress the bleed out of the oligomer contained in the polyester film, and to suppress the crystal derived from the oligomer toward the resin. Since the surface of the layer 12 is deposited, it is possible to suppress the incorporation of fine foreign matter derived from the oligomer or the damage of the transparent electrode layer, which is a defect of the touch panel. Further, the heat-resistant adhesive sheet 1 of the present embodiment can also be applied to applications requiring heat treatment other than the step of manufacturing a touch panel using a transparent conductive film.

As described above, according to the above embodiment, since the initial haze value of the peeling film 10 and the absolute value of the difference in the haze value after heating at 150 ° C for 2 hours are 0.15% or less, the amount can be reduced. The haze value of the release film 10 before and after the heat treatment is changed, and the heat-resistant adhesive sheet 1 provided with the transparent conductive layer can be annealed in a state in which the adhesive layer 14 is provided. By the release film 10 including the release substrate 11, the resin layer 12, and the release agent layer 13, the back side of the functional layer (for example, the transparent conductive layer 22) provided on the base film 21 can be protected, so that the manufacturing can be omitted. In the case of the functional film, the step of removing the protective sheet on the back side of the functional layer is removed. Therefore, the heat-resistant adhesive sheet in which the manufacturing cost of the functional film is reduced can be achieved because the manufacturing process is shortened.

(Manufacturing method of functional film)

Next, a method of manufacturing the functional film of the present embodiment will be described with reference to Figs. 4A to 4C. Here, as an example of a functional film Although a transparent conductive film is produced, the present invention is applicable to the production of various functional films other than the transparent conductive film.

As shown in FIGS. 4A to 4C, the method for producing a functional film according to the present embodiment includes the steps of: the resin layer 12, the release substrate 11, the release agent layer 13, the adhesive layer 14, and the base film 21; The lamination step of the laminate 3 is carried out in sequence, and a conductive material is formed on the base film 32 to obtain a film-forming step of the heat-resistant adhesive sheet 1 on which the functional layer (for example, the transparent conductive layer 22) is provided, and the heat-resistant adhesive is adhered. The heat treatment step of heat treatment of the sheet.

As shown in FIG. 4A, the resin layer 12 is provided on the main surface of one of the release substrates 11 by applying a composition for forming a resin layer by a meyer bar coating method or the like, while the resin layer 12 is provided. The sub-bar coating method is equivalent to the application of the release agent layer-forming composition on the other main surface of the release substrate 11, and the release film 10 provided with the release agent layer 13 is obtained. Next, as shown in FIG. 4B, after the adhesive layer 14 is applied to the release agent layer 13 by applying the adhesive layer-forming composition, the base film 21 is placed on the adhesive layer 14 to form the laminate 3.

Next, as shown in FIG. 4C, a heat-resistant adhesive sheet 1 is obtained by providing a transparent conductive layer 22 (ITO: indium tin oxide film) on the base film 21 by sputtering, CVD, or PVD. Next, in the heat treatment step, ITO is crystallized by annealing the heat-resistant adhesive sheet 1, and the low-resistance transparent electrode layer 22 is formed. The release film 10 is provided on the back side of the outer surface of the transparent conductive layer 22, so that the back side of the transparent conductive layer 22 can be protected without sticking to another protective sheet or the like. Fire treatment can reduce manufacturing costs due to shortened manufacturing steps.

[Examples]

Hereinafter, the present invention will be described in more detail based on examples made to clarify the effects of the present invention. Further, the present invention is not limited by the following examples and comparative examples.

<△ Calculation of haze value>

The heat-resistant adhesive sheets produced in the examples and the comparative examples were cut into 5 cm sides to prepare test pieces. The peeling film was peeled off from the test piece, and the haze of the peeling film (the average value of N=5) was measured by the haze meter (product name: NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7105, and the initial haze was determined. value(%). Further, the corners of the test pieces were fixed by a jig, and after being hung in a dryer at 150 ° C for 2 hours, the release film was peeled off from the test piece, and the haze of the release film was measured in accordance with JIS K7105 (average of N = 5). Value), set to the haze value (%) after heating.

The absolute value of the value obtained by subtracting the initial haze value from the haze value after heating was used as the Δ haze value, and was evaluated by the following criteria. In addition, when the Δ haze value is 0.15% or less, the amount of oligomer eluted from the polyester film used as the release substrate is relatively small, and the influence on the subsequent steps can be reduced.

○ (good): 0.15% or less

× (bad): 0.15% or more

(Example 1) (Modulation step of composition for forming a resin layer)

(A) bisphenol A type epoxy compound (trade name: EPICLON H-360, manufactured by DIC Corporation: solid content concentration: 40% by mass, weight average molecular weight: 25,000) 100 parts by mass, (B) polyester compound (trade name: BYRON GK680, manufactured by Toyobo Co., Ltd.: a toluene solution having a number average molecular weight of 6000 and a glass transition temperature of 10 ° C (solid content: 30% by mass) of 19.0 parts by mass, and (C) hexamethoxymethylmelamine (trade name: CYMEL 303, The solid content concentration was 100% by mass, manufactured by CYTEC INDUSTRIES, Japan, and 11.4 parts by mass. The mixed solution was diluted with a mixed solvent of toluene/methyl ethyl ketone (hereinafter also referred to as "MEK") = 50% by mass/50% by mass to a solid content of 3% by mass and stirred. Subsequently, (D) 2.9 parts by mass of a methanol solution (solid content concentration: 50% by mass) of p-toluenesulfonic acid was added to obtain a resin layer-forming composition.

(Step of manufacturing resin film forming film)

The obtained resin layer-forming composition was uniformly applied to a biaxially-oriented polyethylene terephthalate film (trade name: E5001, manufactured by Toyobo Co., Ltd.: thickness: 75 μm) as a base film by a horse bar coating method. On the surface. Subsequently, the substrate film coated with the resin-forming composition was passed through an oven at 150 ° C for 20 seconds to form a resin layer having a thickness of 150 nm, thereby obtaining a polyester film having a resin layer formed thereon.

(Preparation step of composition for forming a release agent layer)

Next, an addition reaction type polyoxynoxy resin (trade name: KS-774, 100 parts by mass of a mixed solvent of toluene/MEK=50% by mass/50% by mass was diluted to a solid content of 1.5% by mass and stirred. Subsequently, 1 part by mass of a platinum catalyst (trade name: PL-50T, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to obtain a composition for forming a release agent layer.

(Step of manufacturing the release film)

Next, a composition for forming a release agent layer was uniformly applied to the surface of the base film opposite to the resin layer by a horse bar coating method. Subsequently, the substrate film on which the composition for forming a release agent layer was applied was passed through an oven at 150 ° C for 20 seconds to form a release agent layer having a thickness of 150 nm to obtain a release film.

(adhesive modulation step)

The coating composition was prepared by dissolving the adhesive composition prepared by the following formulation ratio (solid content ratio) of the adhesive formulation 1 in toluene.

<Adhesive Formulation 1>

. Acrylic copolymer (copolymer of 95 parts by mass of butyl acrylate and copolymer of 2-hydroxyethyl acrylate, 5 parts by mass, weight average molecular weight (Mw) 800,000), 100 parts by mass

. Polyfunctional acrylate compound (paraben (propylene oxyethyl) isocyanurate; manufactured by Toagosei Co., Ltd., trade name "ARONIX M-315") 15 parts by mass

. Photopolymerization initiator (mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1:1; CIBA SPECIALITY CHEMICALS Company system, trade name "IGRACURE 500") 1.5 parts by mass

. Crosslinking agent (toluene diisocyanate modified by trimethylolpropane; manufactured by Japan POLYURETHANE Co., Ltd., trade name "CORONATE L") 3 parts by mass

.矽 偶 coupling agent (3-glycidoxypropyltrimethoxy decane; manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") 0.2 parts by mass

(Step of manufacturing heat-resistant adhesive sheet)

The prepared coating liquid was applied onto the release layer of the release film prepared in the above step by a knife coater, followed by drying treatment at 90 ° C for 1 minute. Next, the annealed polyester film (trade name: MELINEX SA, thickness: 125 μm, manufactured by Teijin DuPont) was bonded to the base film. The thickness of the adhesive layer after drying was adjusted to 25 μm. Then, 30 minutes after the base film was bonded to the release film, ultraviolet rays (UV) were irradiated from the peeling film side at an illuminance of 600 mW/cm ² and a light amount of 150 mJ/cm ² (using an electrodeless lamp H bulb manufactured by FUSION Co., Ltd.). A heat-resistant adhesive sheet is produced. The resulting adhesive layer had a storage elastic modulus at 23 ° C of 0.86 MPa and a gel fraction of 93%.

(Example 2)

The (D) p-toluenesulfonic acid methanol solution was set to 3.3 mass, except that the resin layer-forming composition system (B) polyester compound was 22.22 parts by mass, and (C) hexamethoxymethyl melamine was 20 parts by mass. A heat-resistant adhesive sheet was obtained in the same manner as in Example 1 except for the portion.

(Example 3)

The (D) p-toluenesulfonic acid methanol solution was set to 3.3 mass, except that the resin layer-forming composition system (B) polyester compound was set to 44.4 parts by mass, and (C) hexamethoxymethyl melamine was set to 13.3 parts by mass. A heat-resistant adhesive sheet was obtained in the same manner as in Example 1 except for the portion.

(Example 4)

In addition to the resin layer-forming composition, the (A) bisphenol A epoxy compound was changed to (product name: EPICLON EXA-123, manufactured by DIC Corporation: solid content concentration: 30%, weight average molecular weight: 45,000), 100 parts by mass, ( B) The polyester compound was 14.3 parts by mass, (C) hexamethoxymethyl melamine was 8.6 parts by mass, and the (D) p-toluenesulfonic acid methanol solution (solid content concentration: 50% by mass) was 2.1 parts by mass. A heat-resistant adhesive sheet was obtained in the same manner as in Example 1 except for the operation.

(Example 5)

Other than the toluene solution (solid content concentration: 30% by mass) of the resin layer-forming composition (B) polyester compound (product name: BYRON GK810, manufactured by Toyobo Co., Ltd.: number average molecular weight: 6000, glass transition temperature: 46 ° C) A heat-resistant adhesive sheet was obtained in the same manner as in Example 1.

(Example 6)

In addition to changing the formulation of the adhesive composition to the following adhesive formulation 2, and the drying treatment was carried out at 120 ° C for 1 minute, and a heat-resistant adhesive sheet was obtained in the same manner as in Example 1 except that ultraviolet irradiation was not performed. The storage modulus of the adhesive layer at 23 ° C was 0.61 MPa, and the gel fraction was 88%.

<Adhesive Formula 2>

. 100 parts by mass of an acrylic copolymer (80 parts by mass of butyl acrylate, 10 parts by mass of methyl methacrylate, 10 parts by mass of 2-hydroxyethyl methacrylate, and a weight average molecular weight (Mw) of 800,000)

. Crosslinking agent 1 (toluene diisocyanate (TDI) crosslinking agent; manufactured by Toyo Ink Co., Ltd., trade name "ORIBAIN BHS8515") 2.6 parts by mass

. Crosslinking agent 2 (metal chelate crosslinking agent; manufactured by Zaiken Chemical Co., Ltd., trade name "M-5A") 0.25 parts by mass

(Example 7)

An adhesive sheet was obtained in the same manner as in Example 1 except that the formulation of the adhesive composition was changed to the following adhesive formulation 3, and ultraviolet irradiation was not performed. The storage modulus of the adhesive layer at 23 ° C was 0.58 MPa, and the gel fraction was 75%.

<Adhesive Formulation 3>

. Acrylic copolymer (94.9 parts by mass of butyl acrylate, 5 parts by mass of 2-hydroxyethyl acrylate and 0.1 parts by mass of acrylic acid, weight average molecular weight (Mw) 1.8 million) 100 parts by mass

. Crosslinking agent (toluene diisocyanate modified by trimethylolpropane; manufactured by Japan POLYURETHANE Co., Ltd., trade name "CORONATE L") 3 parts by mass

(Comparative Example 1)

An adhesive sheet was obtained in the same manner as in Example 1 except that the resin layer was not provided on the release film.

(Comparative Example 2)

In addition to the (B) polyester compound, (C) hexamethoxymethyl melamine is 10 parts by mass, and the (D) p-toluenesulfonic acid methanol solution is 2.5 parts by mass, An adhesive sheet was obtained in the same manner as in Example 1.

(Comparative Example 3)

The (D) p-toluenesulfonic acid methanol solution was set to 6.7 mass, except that the resin layer-forming composition system (B) polyester compound was 222.2 parts by mass, and (C) hexamethoxymethyl melamine was set to 26.7 parts by mass. An adhesive sheet was obtained in the same manner as in Example 1 except for the portion.

[Table 1]

As is understood from Table 1, the haze change amount of the adhesive sheet of Example 1 to Example 7 was extremely small, and the oligomer component was not precipitated on the outer surface of the release film, and the oligomer sealing property was observed. good. Therefore, the adhesive sheets of Examples 1 to 7 do not precipitate oligomers even when heat-treated on the outer surface of the release film, so that even if the adhesive sheets are taken up, the functional layer is not damaged by the oligomer, and the expensive ones are not used. The protective film for the oligomer sealing can be subjected to heat treatment.

On the other hand, in Comparative Example 1 in which the resin layer was not provided, the Δ haze was extremely large, and a large amount of oligomers were precipitated, and it was found that the oligomer sealing property was remarkably inferior. In addition, in Comparative Example 3 in which Comparative Example 2 in which the polyester compound was not blended and the content of the polyester compound were not provided in the case where the resin layer was provided, the Δ haze was large and the oligomer sealing property was insufficient. Therefore, when the adhesive sheet of Comparative Example 1 to Comparative Example 3 is subjected to heat treatment such as annealing treatment and the adhesive sheet is wound up, the oligomer component which is deposited on the outside of the release film by heat treatment is transferred to the functional layer. The side surface becomes the cause of the deterioration of the electrical or optical properties of the functional layer.

1‧‧‧Heat resistant adhesive sheet

10‧‧‧Release film

11‧‧‧ peeling substrate

12‧‧‧ resin layer

13‧‧‧ Stripper layer

14‧‧‧Adhesive layer

21‧‧‧Substrate film

Claims (10)

A heat-resistant adhesive sheet comprising: a release film comprising a release substrate made of a polyester film; a resin layer provided on one main surface of the release substrate; and a release layer provided on the release substrate a release agent layer on the other main surface; an adhesive layer provided on the release agent layer; and a base film provided on the adhesive layer, the initial haze value of the release film is heated at 150 ° C for 2 hours The absolute value of the difference in haze value after heating is Δ haze value of 0.15% or less. The heat-resistant adhesive sheet according to claim 1, wherein the release agent layer is formed by hardening an addition reaction type polyfluorene. The heat-resistant adhesive sheet according to claim 1, wherein the resin layer is a composition for forming a resin layer containing (A) a bisphenol A type epoxy compound, (B) a polyester compound, and (C) a polyfunctional amine group compound. The object is hardened. The heat-resistant adhesive sheet according to claim 3, wherein the content of the bisphenol A-type epoxy compound in the resin layer-forming composition is 50% by mass or more and 80% by mass or less, and the content of the polyester compound is 5% by mass or more. 30% by mass or less, and the content of the polyfunctional amine-based compound is 10% by mass or more and 40% by mass or less. The heat-resistant adhesive sheet according to claim 3, wherein the bisphenol A type epoxy compound has a weight average molecular weight of 10,000 or more and 50,000 or less. The heat-resistant adhesive sheet according to claim 3, wherein the polyester compound has a glass transition temperature (Tg) of from 0 ° C to 50 ° C. The heat-resistant adhesive sheet of claim 1, wherein the resin layer is A coating layer formed by applying a solution of the composition for forming a resin layer onto the base film is heated to form a cured film. The heat-resistant adhesive sheet according to claim 1, wherein the resin layer has a film thickness of 50 nm or more and 500 nm or less. A method for producing a functional film, comprising the steps of: comprising a release substrate made of a polyester film, a resin layer provided on one main surface of the release substrate, and a release layer; The adhesive layer and the base film are sequentially laminated on the release agent layer of the release film of the release agent layer on the other main surface of the material, and the initial haze value of the release film is obtained and heated at 150 ° C. a laminating step of a heat-resistant adhesive sheet having an absolute value of the difference in haze value after heating after 2 hours, and a film having a haze value of 0.15% or less is formed on the base film of the heat-resistant adhesive sheet as a functional layer A film forming step of the conductive material, and a heat treatment step of heat-treating the heat-resistant adhesive sheet on which the functional layer is formed. The method of producing a functional film according to claim 9, wherein the functional layer is a transparent conductive layer.