JP2016210929A - Substrate having pressure-sensitive adhesive layer and light-transmitting conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate having a pressure-sensitive adhesive layer, which is used for a light-transmitting conductive film and with which electric conductivity of the light-transmitting conductive film is scarcely reduced.SOLUTION: A substrate having a pressure-sensitive adhesive layer includes a substrate and a pressure-sensitive adhesive layer which is laminated on one surface of the substrate and which has light transmitting property. In the substrate and the pressure-sensitive adhesive layer, when a test piece, formed by lamination of a substrate for test piece and a pressure-sensitive adhesive layer for test piece and having dimensions of 1 cm length, 1 cm width and 100 μm total thickness is formed such that the substrate for test piece has dimensions of 1 cm length, 1 cm width and 50 μm thickness and the pressure-sensitive adhesive layer for test piece has dimensions of 1 cm length, 1 cm width and 50 μm thickness, and a measurement of the test piece with a thermogravimetry-mass simultaneous analyzer is conducted, a moisture content obtained by a peak area of water of mass 18 is 1.5 g/cmor less.SELECTED DRAWING: None

Description

  The present invention relates to a base material with a pressure-sensitive adhesive layer in which a light-sensitive adhesive layer is laminated on a base material. Moreover, this invention relates to a light transmissive conductive film provided with the said base material with an adhesive layer.

  In recent years, touch panel liquid crystal display devices have been widely used in electronic devices such as smartphones, mobile phones, notebook computers, tablet PCs, copiers, and car navigation systems. In such a liquid crystal display device, a light transmissive conductive film in which a transparent conductive layer is laminated on a substrate is used.

Patent Document 1 below describes a method for producing a light-transmitting conductive film in which a transparent conductive layer of In / Sn composite oxide is formed by sputtering. Patent Document 1 describes that the partial pressure of water in the film forming step is preferably 2.0 × 10 ⁻⁴ Pa or less.

Japanese Patent No. 5543907

  In the liquid crystal display device, the light-transmitting conductive film as in Patent Document 1 is bonded to another component member using an adhesive or the like.

  However, as a result of the study by the present inventors, the surface resistance value of the conductive layer is increased by the trace amount of water contained in the adhesive used for joining with other components, and the conductivity of the light-transmitting conductive film is increased. It has been found that there is a problem of degradation.

  An object of the present invention is to provide a base material with an adhesive layer that is used for a light-transmitting conductive film and hardly lower the conductivity of the light-transmitting conductive film, and light provided with the base material with an adhesive layer. The object is to provide a transparent conductive film.

The base material with the pressure-sensitive adhesive layer according to the present invention is a base material with a pressure-sensitive adhesive layer provided with a base material and a pressure-sensitive adhesive layer that is laminated on one surface of the base material. The base material with the pressure-sensitive adhesive layer has a light-transmitting conductive layer disposed on the surface side opposite to the pressure-sensitive adhesive layer side of the base material, and the conductive layer, the base material, and the pressure-sensitive adhesive layer. The base material and the pressure-sensitive adhesive layer have a size of 1 cm in length, 1 cm in width, and 50 μm in thickness. 1 cm in length, 1 cm in width and the total thickness in which the base material for test piece and the pressure-sensitive adhesive layer for test piece are laminated so that the pressure-sensitive adhesive layer for piece has a size of 1 cm in length, 1 cm in width and 50 μm in thickness. A test piece having a size of 100 μm is prepared, and the thermal weight and mass of the test piece are simultaneously When subjected to measurement by analysis device, which is a base material and the pressure-sensitive adhesive layer moisture content obtained from the peak area of the water exhibits a value that is 1.5 / cm ² or less of the mass 18.

  On the specific situation with the base material with an adhesive layer which concerns on this invention, the said base material has a light transmittance.

  On the specific situation with the base material with an adhesive layer which concerns on this invention, the said adhesive layer contains a (meth) acrylic acid ester copolymer.

  On the specific situation with the base material with an adhesive layer concerning this invention, the thickness of the said base material is 5 micrometers or more and 300 micrometers or less, and the thickness of the said adhesive layer is 2 micrometers or more and 300 micrometers or less.

  The light-transmitting conductive film according to the present invention is disposed on the surface of the base material opposite to the pressure-sensitive adhesive layer side of the base material with the pressure-sensitive adhesive layer configured according to the present invention, and is light-transmitting. And a conductive layer.

  The light-transmitting conductive film according to the present invention can be suitably used for a liquid crystal display device.

  The base material with an adhesive layer which concerns on this invention is a base material with an adhesive layer provided with the base material and the adhesive layer which is laminated | stacked on one surface of the said base material, and has a light transmittance. .

Further, the base material and the pressure-sensitive adhesive layer have a size of a test piece base material of 1 cm in length, 1 cm in width and 50 μm in thickness, and a pressure-sensitive adhesive layer for test piece in 1 cm in length, 1 cm in width and 50 μm in thickness. A test piece having a size of 1 cm in length, 1 cm in width, and a total thickness of 100 μm in which the base material for the test piece and the pressure-sensitive adhesive layer for the test piece are laminated so as to have a size of It is a base material and a pressure-sensitive adhesive layer that show a value in which the amount of water obtained from the peak area of water with a mass of 18 is 1.5 g / cm ² or less when measured with a piece of thermogravimetric / mass simultaneous analyzer. .

  Therefore, the base material with an adhesive layer of this invention can be used for a light transmissive conductive film, and it is hard to reduce the electroconductivity of this light transmissive conductive film.

  Hereinafter, the present invention will be described in detail.

(Base material with adhesive layer)
The base material with an adhesive layer which concerns on this invention is equipped with a base material and an adhesive layer. The pressure-sensitive adhesive layer is laminated on one surface (first surface) of the substrate. The pressure-sensitive adhesive layer has light transmittance.

  The base material and the pressure-sensitive adhesive layer have a moisture content when measured by the following predetermined thermogravimetric / mass simultaneous analyzer (TG-MS) as described below. It is.

  When measuring with the thermogravimetric / mass simultaneous analyzer, first, a test piece having a size of 1 cm in length, 1 cm in width, and a total thickness of 100 μm, in which a base material for a test piece and an adhesive layer for a test piece are laminated. Make it. The test piece substrate is prepared to have a size of 1 cm in length, 1 cm in width, and a thickness of 50 μm. The pressure-sensitive adhesive layer for the test piece is prepared so as to have a size of 1 cm in length, 1 cm in width, and a thickness of 50 μm. The test piece can be produced by cutting out a part of the substrate with the pressure-sensitive adhesive layer of the present invention. In addition, you may produce the said test piece as an object for a test separately from the base material with an adhesive layer of this invention.

  Next, the above-mentioned test piece is measured by a thermogravimetric / mass simultaneous analyzer. The water content of the test piece can be determined from the peak area of water having a mass of 18 as measured by the thermogravimetric / mass simultaneous analyzer.

The said base material which comprises the base material with an adhesive layer of this invention, and the said adhesive layer show the value whose moisture content of the test piece calculated | required as mentioned above is 1.5 g / cm < ² > or less. And an adhesive layer. Therefore, when the base material with an adhesive layer of this invention is used for a light transmissive conductive film, it is hard to reduce the electroconductivity of a light transmissive conductive film.

From the viewpoint of further increasing the conductivity of the light transmissive conductive film, it is preferable that the moisture content of the test piece is small. The moisture content of the test piece is preferably 1.0 g / cm ² or less, more preferably 0.8 g / cm ² or less, further preferably 0.6 g / cm ² or less, 0 It is particularly preferable that it is ⁴ g / cm ² or less.

(Light transmissive conductive film)
The light-transmitting conductive film of the present invention includes a base material with an adhesive layer configured according to the present invention and a conductive layer. The said conductive layer is arrange | positioned at the surface (2nd surface) side opposite to the said adhesive layer side of the said base material which comprises the said base material with an adhesive layer. The said conductive layer is laminated | stacked on the surface on the opposite side to the said adhesive layer side of the said base material. The conductive layer may be provided directly or indirectly on the surface of the substrate opposite to the pressure-sensitive adhesive layer. The conductive layer is light transmissive.

The base material and the pressure-sensitive adhesive layer constituting the light-transmitting conductive film of the present invention have a value in which the moisture content of the test piece obtained by the above-mentioned thermogravimetric and mass simultaneous measurement is 1.5 g / cm ² or less. It is the base material and adhesive layer which are shown. Therefore, it is difficult for the surface resistance value of the conductive layer to be increased by moisture contained in the pressure-sensitive adhesive layer, and the light-transmitting conductive film of the present invention is excellent in conductivity. Therefore, the light transmissive conductive film of the present invention is excellent in reliability.

  Since the light-transmitting conductive film of the present invention is excellent in conductivity, it can be suitably used for a liquid crystal display device. In particular, since higher conductivity is required for touch panel applications, the light-transmitting conductive film of the present invention can be particularly suitably used for touch panel applications.

  Hereinafter, other details of the light-transmitting conductive film according to the present invention will be described.

(Base material)
The substrate preferably has high light transmittance. Accordingly, the material of the base material is not particularly limited. For example, polyolefin, polyethersulfone, polysulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate. , Triacetyl cellulose, cellulose nanofiber, and the like. The substrate is preferably formed of a resin. These may be used alone or in combination.

  Although the thickness of a base material is not specifically limited, It is preferable that it is 5 micrometers or more, It is more preferable that it is 10 micrometers or more, It is preferable that it is 300 micrometers or less, It is more preferable that it is 200 micrometers or less. When the thickness of the base material is not less than the above lower limit and not more than the above upper limit, the light transmittance can be further increased and the thickness can be further reduced.

  Further, the light transmittance of the substrate is preferably 85% or more, more preferably 88% or more, in the visible light region having a wavelength of 380 to 780 nm.

  In addition, the substrate may contain various stabilizers, ultraviolet absorbers, plasticizers, lubricants, or colorants.

(Adhesive layer)
The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive. Although the said adhesive is not specifically limited, It is preferable that the (meth) acrylic acid ester copolymer is included. The content of the (meth) acrylic acid ester copolymer in the pressure-sensitive adhesive layer is preferably 50% by weight or more, more preferably 60% by weight or more, and further preferably 70% by weight or more. preferable. When content of the said (meth) acrylic acid ester copolymer is more than the said minimum, the light transmittance of an adhesive layer can be improved further.

  Examples of the (meth) acrylic acid ester copolymer include a structural unit derived from 2-ethylhexyl (meth) acrylate, a structural unit derived from n-butyl (meth) acrylate, a structural unit derived from isobornyl (meth) acrylate, and ethylene oxide. A copolymer having a structural unit derived from a monomer (PEO chain-containing monomer) having a polyethylene oxide (PEO) chain having a repeating number of 8 to 45 and one olefinic double bond can be used. The proportion of the structural unit derived from the 2-ethylhexyl (meth) acrylate in the (meth) acrylic acid ester copolymer is preferably 5% by weight or more.

  The proportion of the structural unit derived from isobornyl (meth) acrylate is not particularly limited, but is preferably 15% by weight or more, more preferably 18% by weight or more, and preferably 40% by weight or less, 35 More preferably, it is less than or equal to weight percent. When the proportion of the structural unit is equal to or more than the above lower limit, when an adherend that generates outgas is used, it is even more difficult for floating to occur at the adhesive interface with the adherend. When the proportion of the structural unit is less than or equal to the above upper limit, the adhesiveness of the pressure-sensitive adhesive layer to the adherend is unlikely to decrease, and it becomes easy to eliminate entrained bubbles such as bubbles.

  By using a (meth) acrylic acid ester copolymer having a structural unit derived from the PEO chain-containing monomer, the pressure-sensitive adhesive layer is bonded to an adherend and exposed to high temperature and high humidity, and even when returned to room temperature, Water can be finely dispersed, and as a result, whitening of the pressure-sensitive adhesive layer can be further suppressed.

  In the PEO chain-containing monomer, the number of ethylene oxide repeats is preferably 8 or more and 45 or less. By making the repeating number of ethylene oxide more than the above lower limit and below the above upper limit, whitening of the pressure-sensitive adhesive layer can be further suppressed, and the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer to the adherend can be further increased. it can.

  The PEO chain-containing monomer is not particularly limited, but is preferably a monomer represented by the following formula (1) because whitening can be more effectively suppressed.

(In Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 30 carbon atoms, and n represents an integer of 8 to 45.)

Among them, from the viewpoint of further enhancing the whitening suppression effect, in the above formula (1), R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group having 18 carbon atoms, and n is 30; Alternatively, in the above formula (1), it is preferable that R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group having 1 carbon atom, and n is 23. Since these monomers can suppress whitening by addition of a small amount, the glass transition temperature (Tg) of the (meth) acrylic acid ester copolymer is not increased more than necessary, and the reliability of the pressure-sensitive adhesive layer is improved. be able to.

  Commercially available products of the above PEO chain-containing monomer include, for example, Blemmer PME-1000 (ethylene oxide repeat number = 23, terminal methyl group, manufactured by NOF Corporation), Blemmer PME-400 (ethylene oxide repeat number = 9, terminal) Methyl group, manufactured by NOF Corporation), BLEMMER PME-2000 (ethylene oxide repeat number = 45, terminal methyl group, NOF Corporation), NK ester AM-130G (ethylene oxide repeat number = 13, terminal methyl group, Shin Nakamura Chemical Co., Ltd.), Light Ester 041MA (ethylene oxide repeat number = 30, terminal methyl group, manufactured by Kyoeisha Chemical Co., Ltd.), Bremer PSE-1300 (ethylene oxide repeat number = 30, terminal octadecyl group, NOF Corporation) ), Blemmer AE-400 (ethylene oxide recycle) And number = 10, a terminal hydroxyl group, manufactured by NOF CORPORATION) or Blenmer ANE-1300 (number of repetitions of ethylene oxide = 30, terminal nonylphenyl group, NOF Corp.), and the like.

  The proportion of the structural unit derived from the PEO chain-containing monomer in the (meth) acrylic acid ester copolymer is not particularly limited, but is preferably 0.5% by weight or more, and 0.7% by weight or more. Is more preferably 0.9% by weight or more, preferably 10% by weight or less, more preferably 8% by weight or less, and further preferably 6% by weight or less.

  When the proportion of the structural unit derived from the PEO chain-containing monomer is not less than the above lower limit, whitening is further suppressed. When the proportion of the structural unit is not more than the above upper limit, the adhesiveness of the pressure-sensitive adhesive layer to the adherend is further increased, and the reliability of the pressure-sensitive adhesive layer is increased.

  The (meth) acrylic acid ester copolymer may contain a structural unit derived from a monomer (carboxyl group-containing monomer) having a carboxyl group and one olefinic double bond. When the said (meth) acrylic acid ester copolymer contains the structural unit derived from a carboxyl group-containing monomer, intermolecular interaction increases and the cohesive force of an adhesive layer can be improved further.

  The carboxyl group-containing monomer is not particularly limited, and examples thereof include (meth) acrylic acid, (meth) acryloyl acetic acid, (meth) acryloylpropionic acid, (meth) acryloylbutyric acid, (meth) acryloylpentanoic acid, crotonic acid and the like. And unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and itaconic acid.

  The proportion of the structural unit derived from the carboxyl group-containing monomer in the (meth) acrylic acid ester copolymer is not particularly limited, but is preferably 3% by weight or less, more preferably 2% by weight or less. More preferably, it is 5% by weight or less. An adherend becomes difficult to deteriorate that the ratio of the structural unit derived from the said carboxyl group-containing monomer is below the said upper limit.

  The weight average molecular weight of the (meth) acrylic acid ester copolymer is preferably 600,000 or more, more preferably 700,000 or more, further preferably 800,000 or more, and 900,000 or more. Is particularly preferably 2 million or less, more preferably 1.8 million or less, further preferably 1.6 million or less, and particularly preferably 1.4 million or less.

  When the weight average molecular weight of the (meth) acrylic acid ester copolymer is not less than the above lower limit, the high temperature elastic modulus of the pressure-sensitive adhesive layer is hardly excessively lowered and the reliability is improved. When the weight average molecular weight of the (meth) acrylic acid ester copolymer is not more than the above upper limit, the fluidity of the pressure-sensitive adhesive layer is hardly excessively lowered and the adhesion to an adherend is further enhanced. The weight average molecular weight of the (meth) acrylic acid ester copolymer is a value measured by gel permeation chromatography (GPC) in terms of polystyrene.

  Specifically, the diluted solution obtained by diluting the (meth) acrylic acid ester copolymer 100 times with tetrahydrofuran (THF) is filtered through a filter, and the obtained filtrate is subjected to column (for example, Showa Denko). The weight average molecular weight of the (meth) acrylic acid ester copolymer can be determined by GPC measurement using a SHOWDEX column LF-804, etc.

  The pressure-sensitive adhesive preferably further contains a crosslinking agent. By using the crosslinking agent, a crosslinked structure can be formed in the (meth) acrylic acid ester copolymer. Moreover, the gel fraction of an adhesive layer can be adjusted by adjusting the kind or quantity of the said crosslinking agent suitably.

  The crosslinking agent is not particularly limited, and examples thereof include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, and a metal chelate crosslinking agent. These may be used alone or in combination. Especially, it is preferable that the said crosslinking agent is an isocyanate type crosslinking agent or an epoxy-type crosslinking agent from a viewpoint of improving the heat resistance and durability of the said adhesive layer further.

  Although it does not specifically limit as said isocyanate type crosslinking agent, An aliphatic isocyanate type crosslinking agent is preferable. As a commercial item of the said aliphatic isocyanate type crosslinking agent, Coronate HX (made by Nippon Polyurethane) or Mytec NY260A (made by Mitsubishi Chemical Corporation) etc. are mentioned, for example.

  Although it does not specifically limit as said epoxy type crosslinking agent, An aliphatic epoxy type crosslinking agent is preferable. Examples of commercially available products of the aliphatic epoxy crosslinking agent include Denacol EX212 (manufactured by Nagase ChemteX), Denacol EX214 (manufactured by Nagase ChemteX), E-5C (manufactured by Soken Chemical Co., Ltd.), and the like. Examples of the other epoxy-based crosslinking agent include E-AX (manufactured by Soken Chemical Co., Ltd.).

  The blending amount of the crosslinking agent is not particularly limited, but is preferably 0.1 parts by weight or more, and 0.3 parts by weight or more with respect to 100 parts by weight of the (meth) acrylic acid ester copolymer. More preferred is 10 parts by weight or less, and more preferred is 3 parts by weight or less.

  The pressure-sensitive adhesive may further contain a tackifier resin. The tackifying resin is not particularly limited, and examples thereof include a xylene resin, a phenol resin, a rosin resin, and a terpene resin. These tackifier resins may be used alone or in combination. Especially, as said tackifier resin, it is preferable that it is a xylene resin, and it is more preferable that it is the alkylphenol reaction material of a xylene resin. The tackifying resin is preferably a hydrogenated resin. By using a hydrogenated resin, the transparency of the pressure-sensitive adhesive layer can be further enhanced.

  The pressure-sensitive adhesive preferably further contains a silane coupling agent. When the pressure-sensitive adhesive contains a silane coupling agent, even when the pressure-sensitive adhesive is bonded to the adherend and exposed to high temperature and high humidity, the resistance value is further prevented from decreasing due to deterioration of the adherend. be able to. Moreover, the adhesiveness of the adhesive layer with respect to a to-be-adhered body can be improved by using a silane coupling agent for the said adhesive.

  The silane coupling agent is not particularly limited. For example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-glycidoxypropyltri Methoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ -Aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethylmethoxysilane, N- (2-aminoethyl) 3-aminopropyltriethoxysilane, N- (2-aminoethyl) 3-aminopropyl Pills methyldimethoxysilane, .gamma.-mercaptopropyltrimethoxysilane, .gamma.-mercaptopropyl triethoxysilane, and the like-mercapto-butyl trimethoxysilane or .gamma.-mercaptopropyl methyl dimethoxy silane. Of these, an epoxy group-containing silane coupling agent is suitable as the silane coupling agent.

  The amount of the silane coupling agent is not particularly limited, but is preferably 0.01 parts by weight or more, and 0.05 parts by weight or more with respect to 100 parts by weight of the (meth) acrylic acid ester copolymer. Is more preferably 5 parts by weight or less, and more preferably 3 parts by weight or less.

  When the blending amount of the silane coupling agent is not less than the above lower limit, the adhesiveness of the pressure-sensitive adhesive layer to the adherend is hardly lowered, and the resistance value is hardly lowered due to deterioration of the metal thin film. When the blending amount of the silane coupling agent is not more than the above upper limit, the peelability of the release film with respect to the pressure-sensitive adhesive layer is reduced, and even if the release film cannot be peeled or peeled, the surface of the pressure-sensitive adhesive layer is rough. May occur. The release film includes release paper.

  The pressure-sensitive adhesive may further contain a conventionally known additive such as a filler, an antioxidant, or an ultraviolet absorber as necessary within a range not inhibiting the effects of the present invention.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 2 μm or more, more preferably 5 μm or more, further preferably 10 μm or more, particularly preferably 20 μm or more, and 1 mm. Or less, more preferably 500 μm or less, and even more preferably 300 μm or less.

  When the thickness of the pressure-sensitive adhesive layer is not more than the above upper limit, the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer with respect to the adherend is less likely to decrease, and the reliability is improved. When the thickness of the pressure-sensitive adhesive layer is not more than the above upper limit, it is difficult for the pressure-sensitive adhesive component to ooze out, and the handleability of the pressure-sensitive adhesive is enhanced.

(Conductive layer)
The conductive layer is made of a light-transmitting conductive material. As the conductive material is not particularly limited, for example, IZO (indium zinc oxide) or, In-based oxides such as ITO (indium tin _oxide), Sn, such as SnO 2, FTO (fluorine-doped tin oxide) Oxide, AZO (aluminum zinc oxide), Zn oxide such as GZO (gallium zinc oxide), sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum - lithium alloy, Al / _Al 2 _{O 3} mixture, Al / LiF mixture, a metal such as gold, CuI, Ag nanowire (AgNW), such as carbon nanotubes (CNT) or conductive transparent polymers. These may be used alone or in combination.

From the viewpoint of further increasing the conductivity and further increasing the light transmittance, the conductive material is selected from In-based oxides such as IZO (indium zinc oxide) and ITO (indium tin oxide), SnO ₂ , FTO. Sn-based oxides such as (fluorine-doped tin oxide), Zn-based oxides such as AZO (aluminum zinc oxide) and GZO (gallium zinc oxide) are preferable, and ITO (indium tin oxide) is preferable. Is more preferable.

  The thickness of the conductive layer is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, preferably 100 nm or less, and more preferably 50 nm or less.

  When the thickness of a conductive layer is more than the said minimum, the electroconductivity of a transparent conductive film can be improved further. When the thickness of the conductive layer is not more than the above upper limit, the light transmittance can be further increased, and the thickness can be further reduced.

  Further, the light transmittance of the conductive layer is preferably 85% or more, more preferably 88% or more, in the visible light region.

(Production method)
The manufacturing method of a light transmissive conductive film is not specifically limited. As a manufacturing method of a light transmissive conductive film, the following methods are mentioned, for example. The following method is an example, and the manufacturing method can be changed as appropriate.

  First, an adhesive layer is formed on one surface of the substrate. When the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive containing the (meth) acrylic acid ester copolymer, first, the 2-ethylhexyl (meth) acrylate, the n-butyl (meth) acrylate, the isobornyl (meta ) A mixed monomer containing an acrylate, the above PEO chain-containing monomer, and other monomers added as necessary is radically polymerized in the presence of a polymerization initiator to prepare a (meth) acrylic acid ester copolymer. The polymerization method of the mixed monomer is not particularly limited, and examples thereof include conventionally known polymerization methods such as solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization.

  The solvent used for the solution polymerization is not particularly limited, and examples thereof include ethyl acetate, toluene, dimethyl sulfoxide, ethanol, acetone, and diethyl ether. Although the compounding quantity of the solvent used for the said solution polymerization is not specifically limited, It is preferable that it is 25 weight part or more with respect to 100 weight part of said mixed monomers, and it is preferable that it is 300 weight part or less.

  When the blending amount of the solvent is not less than the above lower limit, the molecular weight distribution of the (meth) acrylic acid ester copolymer is appropriately narrowed. In this case, the adhesive force and cohesive force with respect to the adherend are unlikely to decrease, and the reliability of the adhesive layer is increased. When the blending amount of the solvent is not more than the above upper limit, when the pressure-sensitive adhesive is prepared using the (meth) acrylic acid ester copolymer and the pressure-sensitive adhesive layer is formed, the solvent can be easily removed.

  The polymerization initiator is not particularly limited, and examples thereof include persulfates, organic peroxides, and azo compounds. Of these, organic peroxides or azo compounds are preferred in view of the influence on the adherend.

  The persulfate is not particularly limited, and examples thereof include potassium persulfate, sodium persulfate, and ammonium persulfate.

  The organic peroxide is not particularly limited. For example, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxy Pivalate, lauroyl peroxide, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2- Examples thereof include ethyl hexanoate, t-butyl peroxyisobutyrate, t-butyl peroxy-3,5,5-trimethylhexanoate, and t-butyl peroxylaurate.

  The azo compound is not particularly limited. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 4,4′-azobis (4-cyanopentane) Acid), 2,2′-azobis (2-methylbutyronitrile), azobiscyclohexanecarbonitrile and the like. These polymerization initiators may be used alone or in combination of two or more.

  Although the compounding quantity of the said polymerization initiator is not specifically limited, It is preferable that it is 0.02 weight part or more with respect to 100 weight part of said mixed monomers (polymerization component), and it is preferable that it is 0.5 weight part or less. When the blending amount of the polymerization initiator is not less than the above lower limit, the polymerization reaction can proceed sufficiently and the polymerization reaction can be performed in a short time. When the blending amount of the polymerization initiator is not more than the above upper limit, the weight average molecular weight of the (meth) acrylic acid ester copolymer does not become too low and the molecular weight distribution does not become too wide. In this case, the adhesive force and cohesive force of the adhesive to the adherend are further increased, and the reliability is increased.

  The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is the above-described (meth) acrylic acid ester copolymer, the cross-linking agent, the tackifying resin, the silane coupling agent, and the additive as necessary. Etc. can be added, mixed and stirred.

  Next, the base material on which the pressure-sensitive adhesive layer is formed is dried.

  As a drying method, it can be dried in a drying furnace such as an IR heater or an oven. At this time, the drying may be performed under normal pressure or under reduced pressure.

  As drying temperature, 130 degreeC or more is preferable, 140 degreeC or more is more preferable, 150 degreeC or more is further more preferable, and 200 degreeC or less is preferable. When the drying temperature is not less than the above lower limit and not more than the above upper limit, the moisture content of the substrate and the pressure-sensitive adhesive layer can be further reduced, and the conductivity of the light-transmitting conductive film can be further increased.

  Moreover, it does not specifically limit as drying time, 5 minutes or more are preferable, 10 minutes or more are more preferable, 15 minutes or more are further more preferable, and 60 minutes or less are preferable. When the drying time is not less than the above lower limit and not more than the above upper limit, the moisture content of the substrate and the pressure-sensitive adhesive layer can be further reduced, and the conductivity of the light-transmitting conductive film can be further increased.

  In the present invention, only the pressure-sensitive adhesive may be dried before forming the pressure-sensitive adhesive layer on the substrate. Even in that case, when used in the light-transmitting conductive film, the conductivity of the light-transmitting conductive film can be increased.

  Next, a conductive layer is formed on the main surface on the other side of the substrate. The method for forming the conductive layer is not particularly limited. For example, a method of etching a metal film formed by vapor deposition or sputtering, various printing methods such as screen printing or inkjet printing, and a known patterning method such as a photolithography method using a resist can be used.

  In the present invention, the conductive layer may be formed on the substrate prior to the pressure-sensitive adhesive layer, and the production order of the pressure-sensitive adhesive layer and the conductive layer is not particularly limited.

  Hereinafter, the present invention will be described in more detail based on specific examples. The present invention is not limited to the following examples.

Example 1
Production of a substrate with an adhesive layer;
An adhesive (trade name “# 5405” manufactured by Sekisui Chemical Co., Ltd.) was applied onto a PET film having a thickness of 50 μm to prepare an adhesive layer having a thickness of 50 μm. Subsequently, the film on which the pressure-sensitive adhesive layer was formed was placed in an oven and dried for 10 minutes under the condition of a temperature of 130 ° C. to produce a substrate with a pressure-sensitive adhesive layer.

Measurement of moisture content;
From the produced base material with an adhesive layer, a base material with an adhesive layer having a size of 1 cm in length and 1 cm in width was cut out to prepare a test piece. The test piece is as described above so that the base material for the test piece has a size of 1 cm in length, 1 cm in width and a thickness of 50 μm, and the pressure-sensitive adhesive layer for the test piece has a size of 1 cm in length, 1 cm in width and 50 μm in thickness. The test piece base material and the above test piece pressure-sensitive adhesive layer were prepared to have a size of 1 cm in length, 1 cm in width, and a total thickness of 100 μm.

Next, the moisture content calculated | required by the thermogravimetric and mass simultaneous analyzer (TG-MS, the product number STA449F1 + QMS403 by the NETZSCH company) of the produced test piece, and the water | moisture content calculated | required from the peak area of the water of mass (m / z value) 18 The water content volatilized from the adhesive was 0.9 g / cm ² in Example 1. The amount of water volatilized from the pressure-sensitive adhesive is the amount of water obtained from the peak area of water having the mass (m / z value) of 18. In addition, when measuring the water content with the thermogravimetric / mass simultaneous analyzer, a calibration curve was prepared using calcium oxalate hydrate.

Forming a conductive layer;
An ITO layer (conductive layer) was deposited on the surface opposite to the pressure-sensitive adhesive layer side of the substrate with the pressure-sensitive adhesive layer.

  In Example 1, a light-transmitting conductive film was produced as described above.

(Examples 2 to 6 and Comparative Example 1)
The light-transmitting conductive film was set in the same manner as in Example 1 except that the drying temperature and drying time were set as shown in Table 1 below, and a substrate with an adhesive layer having the moisture content shown in Table 1 was prepared. Obtained.

<Evaluation>
The following electroconductive evaluation was performed about the light-transmissive conductive film obtained in Examples 1-6 and Comparative Example 1. The results are shown in Table 1 below.

Conductivity evaluation (measurement of surface resistance)
The obtained light-transmitting conductive film was heat-treated at 150 ° C. for 1 hour. Subsequently, an initial surface resistance value (Ω / □) was measured by a four-probe method using a resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., product number: Loresta AX MCP-T370). Next, another portion of the light transmissive conductive film was left indoors for 1000 hours under conditions of a temperature of 10 to 35 ° C. and a humidity of 20 to 80%. The light-transmitting conductive film after standing was heat-treated at 150 ° C. for 1 hour, and then the surface resistance value (Ω / □) was measured in the same manner as the initial surface resistance value.

Claims (6)

A base material and a base material with a pressure-sensitive adhesive layer which is laminated on one surface of the base material and has a light-transmitting pressure-sensitive adhesive layer,
The base material with the pressure-sensitive adhesive layer has a light-transmitting conductive layer disposed on the surface side opposite to the pressure-sensitive adhesive layer side of the base material, and the conductive layer, the base material, and the pressure-sensitive adhesive layer Used to obtain a light transmissive conductive film comprising:
The base material and the pressure-sensitive adhesive layer have a size of a test piece base material of 1 cm in length, 1 cm in width and 50 μm in thickness, and a pressure-sensitive adhesive layer for test piece in 1 cm in length, 1 cm in width and 50 μm in thickness. A test piece having a size of 1 cm in length, 1 cm in width and a total thickness of 100 μm in which the base material for the test piece and the pressure-sensitive adhesive layer for the test piece are laminated, A pressure-sensitive adhesive that is a base material and a pressure-sensitive adhesive layer having a water content of 1.5 g / cm ² or less determined from a peak area of water having a mass of 18 when measured by a thermogravimetric / mass simultaneous analyzer. Base material with agent layer.   The base material with an adhesive layer of Claim 1 in which the said base material has a light transmittance.   The base material with an adhesive layer of Claim 1 or 2 in which the said adhesive layer contains a (meth) acrylic acid ester copolymer. The substrate has a thickness of 5 μm or more and 300 μm or less,
The base material with an adhesive layer of any one of Claims 1-3 whose thickness of the said adhesive layer is 2 micrometers or more and 300 micrometers or less. The base material with an adhesive layer according to any one of claims 1 to 4,
A light-transmitting conductive film, comprising a conductive layer that is disposed on a surface side opposite to the pressure-sensitive adhesive layer side of the base material and has a light-transmitting property.   The light-transmitting conductive film according to claim 5, which is used for a liquid crystal display device.