JP6357012B2 - Pattern electrode sheet - Google Patents

Description

The present invention relates to a patterned electrode sheet that can suppress deterioration of a transparent metal thin film formed from a silver nanomaterial or the like.

Display panels are used in various fields, and particularly in mobile phones, personal digital assistants, etc., they are used not only for image display devices but also for input devices. In such an input device, for example, a touch panel and a cover panel on the surface are bonded together via a highly transparent adhesive such as an acrylic adhesive or a transparent adhesive tape. Conventionally, a glass plate has been used as a cover panel for a touch panel, but recently, in addition to a glass plate, a safe and lightweight polycarbonate plate, an acrylic plate, or the like is increasingly used.

However, it is known that the polycarbonate plate and the acrylic plate easily absorb moisture, and the moisture is vaporized under high temperature conditions to generate outgas. Therefore, under high temperature conditions, the pressure-sensitive adhesive layer in contact with the polycarbonate plate or the acrylic plate may contain moisture due to outgas.

Moreover, the pressure-sensitive adhesive or transparent pressure-sensitive adhesive tape used for bonding a touch panel in which a transparent metal layer is formed of silver nanomaterials has a pressure-sensitive adhesive layer on the metal thin film surface of the film with a transparent metal thin film made of silver nanomaterials. You will be in direct contact. Therefore, for example, in the pressure-sensitive adhesive or transparent pressure-sensitive adhesive tape used for such applications, it is required to suppress the occurrence of a decrease in conductivity due to deterioration of the metal thin film. In addition, a transparent metal film using a silver nanomaterial is likely to have an increased surface resistance under an outdoor use environment. Therefore, it is required that the increase in surface resistance can be suppressed even under outdoor use environment.

Patent Documents 1 to 5 disclose a method in which a transparent metal thin film made of a silver nanomaterial contains an ultraviolet absorber.

However, a method for suppressing the occurrence of a decrease in conductivity due to deterioration of the metal thin film is not shown for the pressure-sensitive adhesive or transparent pressure-sensitive adhesive tape in contact with the transparent metal thin film made of the silver nanomaterial.

WO2012 / 008346 JP 2013-200953 A JP 2012-133486 A JP2013-513220A JP2012-160181A

An object of this invention is to provide the pattern electrode sheet which can suppress deterioration of the transparent metal thin film which consists of silver nanomaterials.

The present invention is a transparent pressure-sensitive adhesive tape for a transparent conductive film with a transparent metal thin film made of a silver nanomaterial, and comprising a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition containing a (meth) acrylate copolymer as a main component. It is a transparent adhesive tape which has an adhesive layer, and the adhesive layer contains a ultraviolet absorber.
The present invention is described in detail below.

The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer of the transparent pressure-sensitive adhesive tape of the present invention contains a (meth) acrylic acid ester copolymer as a main component.
In the present specification, “main component” means that the pressure-sensitive adhesive is usually 50% by weight or more, preferably 60% by weight, based on the total amount of the pressure-sensitive adhesive. As mentioned above, it means containing 70 weight% or more more preferably.
In the present specification, (meth) acryl means acryl or methacryl.

The pressure-sensitive adhesive layer of the transparent pressure-sensitive adhesive tape of the present invention preferably has a gel fraction of 50% by weight or more. A preferable lower limit of the gel fraction of the pressure-sensitive adhesive layer is 65% by weight, and a more preferable lower limit is 70% by weight. In addition, the upper limit of the gel fraction of the said adhesive layer is not specifically limited, 100 weight% may be sufficient.

The gel fraction can be measured, for example, by the following method.
First, the transparent adhesive tape of this invention is cut | disconnected to a fixed magnitude | size, and a test piece is produced. After immersing the obtained test piece in ethyl acetate at 23 ° C. for 24 hours, the test piece is taken out from ethyl acetate through a 200-mesh stainless steel mesh and dried at 110 ° C. for 1 hour. And the weight of the test piece after drying is measured, and a gel fraction is computed using a following formula.

Gel fraction (% by weight) = 100 × (W ₂ −W ₀ ) / (W ₁ −W ₀ )
In the formula, W ₀ represents the weight of the substrate, W ₁ represents the weight of the test piece before dipping, and W ₂ represents the weight of the test piece after dipping and drying. When the transparent adhesive tape does not have a substrate, W ₀ = 0.

The (meth) acrylic acid ester-based copolymer is represented by a structural unit derived from a (meth) acrylic acid ester monomer having a structure represented by the following general formula (1) and the following general formula (2). It is preferable to have a structural unit derived from a (meth) acrylic acid ester monomer having a structure. The (meth) acrylic acid ester copolymer has a structural unit derived from these (meth) acrylic acid ester monomers, so that the obtained adhesive layer has a shear storage elastic modulus and a gel fraction at 200 ° C. Can fall within range.

In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 4 to 14 carbon atoms. The hydrogen atom of the alkyl group represented by R ² may be substituted with a cycloalkyl group. The cycloalkyl group is not particularly limited, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

In General Formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 3 carbon atoms.

Although the (meth) acrylic acid ester monomer which has a structure represented by the said General formula (1) is not specifically limited, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethyloctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) ) Acrylate, lauryl (meth) acrylate, isotetradecyl (meth) acrylate, and the like. Among them, at least one (meth) acrylic acid ester monomer selected from the group consisting of 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate and n-butyl (meth) acrylate is N-Butyl (meth) acrylate is more preferred.

When the (meth) acrylic acid ester-based copolymer contains a structural unit derived from a (meth) acrylic acid ester monomer having a structure represented by the general formula (1), the general formula (1) Although the ratio of the structural unit derived from the (meth) acrylic acid ester monomer which has a structure represented is not specifically limited, A preferable minimum is 20 weight% and a preferable upper limit is 95 weight%. The more preferable lower limit of the proportion of the structural unit derived from the (meth) acrylic acid ester monomer having the structure represented by the general formula (1) is 30% by weight, the more preferable upper limit is 90% by weight, and the more preferable lower limit is 35 wt%, and a more preferred upper limit is 85 wt%.

The (meth) acrylic acid ester monomer having the structure represented by the general formula (2) is not particularly limited, but methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) At least one (meth) acrylic acid ester monomer selected from the group consisting of acrylates is preferred, and ethyl (meth) acrylate is more preferred.

When the (meth) acrylic acid ester copolymer contains a structural unit derived from a (meth) acrylic acid ester monomer having a structure represented by the general formula (2), it is represented by the general formula (2). The proportion of the structural unit derived from the (meth) acrylic acid ester monomer having the structure is not particularly limited, but the preferred lower limit is 1% by weight and the preferred upper limit is 60% by weight. The more preferable lower limit of the proportion of the structural unit derived from the (meth) acrylic acid ester monomer having the structure represented by the general formula (2) is 2% by weight, the more preferable upper limit is 50% by weight, and the more preferable lower limit is 5% by weight, more preferably the upper limit is 40% by weight, the particularly preferred lower limit is 10% by weight, and the particularly preferred upper limit is 35% by weight.

It is preferable that the (meth) acrylic acid ester-based copolymer further contains a component derived from a monomer having a bicyclo ring structure and one olefinic double bond.

The bicyclo ring structure is not particularly limited, and examples of the functional group having the bicyclo ring structure include a bicyclo [1.1.0] butyl group, a bicyclo [1.1.1] pentyl group, and a bicyclo [2.1. 0] pentyl group, bicyclo [3.1.0] hexyl group, bicyclo [2.1.1] hexyl group, bicyclo [2.2.0] hexyl group, bicyclo [2.2.1] heptyl group, bicyclo [3.1.1] heptyl group, bicyclo [3.2.0] heptyl group, bicyclo [4.1.0] heptyl group, bicyclo [2.2.2] octyl group, bicyclo [3.2.1] ] Octyl group, bicyclo [3.3.0] octyl group, bicyclo [4.1.1] octyl group, bicyclo [4.2.0] octyl group, bicyclo [5.1.0] octyl group, bicyclo [ 3.2.2] Nonyl group, bicyclo 3.3.1] Nonyl group, bicyclo [4.2.1] nonyl group, bicyclo [4.3.0] nonyl group, bicyclo [5.1.1] nonyl group, bicyclo [5.2.0] Nonyl group, bicyclo [6.1.0] nonyl group, bicyclo [4.3.1] decyl group, and a functional group having a structure in which a part of these hydrogen atoms is substituted with a chain alkyl group or a cyclic alkyl group Groups and the like. In addition, the said substitution may be one place and may be multiple places. Among these, the bicyclo ring structure is preferably a norbornyl ring or an isobornyl ring, and particularly preferably an isobornyl ring.

The olefinic double bond is not particularly limited, and examples of the functional group having the olefinic double bond include a (meth) acryloyl group, a vinyl group, and an allyl group. Especially, it is preferable that an olefinic double bond is a double bond of a (meth) acryloyl group, and it is especially preferable that it is a double bond of an acryloyl group.

As the monomer having the bicyclo ring structure and one olefinic double bond, specifically, for example, isobornyl (meth) acrylate having an isobornyl group and a (meth) acryloyl group is preferable, and the isobornyl group and the acryloyl group are preferable. Isobornyl acrylate having is particularly preferred.

When the (meth) acrylic acid ester copolymer contains a structural unit derived from a monomer having the bicyclo ring structure and one olefinic double bond, the bicyclo ring structure and one olefinic double bond Although the ratio of the structural unit derived from the monomer which has these is not specifically limited, A preferable minimum is 10 weight% and a preferable upper limit is 60 weight%. The more preferable lower limit of the proportion of the structural unit derived from the monomer having the bicyclo ring structure and one olefinic double bond is 12% by weight, the more preferable upper limit is 50% by weight, and the still more preferable lower limit is 14% by weight, A more preferred upper limit is 45% by weight, a particularly preferred lower limit is 15% by weight, and a particularly preferred upper limit is 40% by weight.

It is preferable that the (meth) acrylic acid ester-based copolymer further contains a component derived from a monomer having a polyethylene oxide chain having 8 to 45 ethylene oxide repeats and one olefinic double bond. .

Although the monomer having a polyethylene oxide chain having an ethylene oxide repeat number of 8 to 45 and one olefinic double bond is not particularly limited, whitening occurring under high temperature and high humidity can be more effectively suppressed. A monomer having a structure represented by the following general formula (3) is preferable.

In General Formula (3), R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents an alkyl group having 1 to 30 carbon atoms, and n represents an integer of 8 to 45.

In addition, a monomer having a polyethylene oxide chain having 8 to 45 ethylene oxide repeats and one olefinic double bond has a high effect of suppressing whitening that occurs particularly under high temperature and high humidity. In the general formula (3), R ⁵ is a hydrogen atom or a methyl group, R ⁶ is an alkyl group having 18 carbon atoms, and n is 30. In general formula (3), R ⁵ is a hydrogen atom or a methyl group. R ⁶ is an alkyl group having 1 carbon atom, and n is particularly preferably 23.

Among the monomers having a polyethylene oxide chain having an ethylene oxide repeat number of 8 to 45, commercially available products include, for example, BLEMMER PME-1000 (ethylene oxide repeat number = 23, terminal methyl group, manufactured by NOF Corporation), BLEMMER. PME-400 (repetition number of ethylene oxide = 9, terminal methyl group, manufactured by NOF Corporation), BLEMMER PME-2000 (repetition number of ethylene oxide = 45, terminal methyl group, manufactured by NOF Corporation), NK ester AM-130G (Repeat number of ethylene oxide = 13, terminal methyl group, manufactured by Shin-Nakamura Chemical Co., Ltd.), Light Ester 041MA (Repeat number of ethylene oxide = 30, terminal methyl group, manufactured by Kyoeisha Chemical Co., Ltd.), Blemmer PSE-1300 (ethylene oxide) Number of repetitions = 30, terminal octadec Group, manufactured by NOF Corporation), BLEMMER AE-400 (ethylene oxide repeat number = 10, terminal hydroxyl group, NOF Corporation), BLEMMER AE-1300 (ethylene oxide repeat number = 30, terminal nonylphenyl group, NOF) Etc.).

When the (meth) acrylic acid ester-based copolymer contains a structural unit derived from a monomer having a polyethylene oxide chain having 8 to 45 ethylene oxide repeats and one olefinic double bond, the ethylene oxide The proportion of the structural unit derived from a monomer having a polyethylene oxide chain having a repeating number of 8 to 45 and one olefinic double bond is not particularly limited, but a preferred lower limit is 0.5% by weight and a preferred upper limit is 10% by weight. It is. The lower limit of the proportion of the structural unit derived from a monomer having a polyethylene oxide chain having 8 to 45 ethylene oxide repeats and one olefinic double bond is preferably 0.7% by weight, and more preferably 8% by weight. A more preferred lower limit is 0.9% by weight, a more preferred upper limit is 6% by weight, a particularly preferred lower limit is 1% by weight, and a particularly preferred upper limit is 5% by weight.

The (meth) acrylic acid ester copolymer may contain a structural unit derived from a monomer having a carboxyl group and one olefinic double bond. When the (meth) acrylic acid ester-based copolymer contains a structural unit derived from a monomer having a carboxyl group and one olefinic double bond, the intermolecular interaction is increased, and the pressure-sensitive adhesive layer Cohesion is improved.

The monomer which has the said carboxyl group and one olefinic double bond is not specifically limited, For example, (meth) acrylic acid, (meth) acryloyl acetic acid, (meth) acryloyl propionic acid, (meth) acryloyl butyric acid, (meth ) Unsaturated monocarboxylic acids such as acryloylpentanoic acid and crotonic acid, and unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and itaconic acid.

When the (meth) acrylic acid ester-based copolymer contains a structural unit derived from a monomer having the carboxyl group and one olefinic double bond, the carboxyl group and one olefinic double bond are Although the ratio of the structural unit derived from the monomer to have is not specifically limited, A preferable upper limit is 3 weight%. The more preferable upper limit of the ratio of the structural unit derived from the monomer having a carboxyl group and one olefinic double bond is 1.5% by weight, and a more preferable upper limit is 0.5% by weight.

The preferred lower limit of the weight average molecular weight of the (meth) acrylic acid ester copolymer is 600,000, and the preferred upper limit is 1,500,000. When the weight average molecular weight of the (meth) acrylic acid ester copolymer is less than 600,000, the resulting adhesive layer has a low high temperature elastic modulus and a shear storage elastic modulus at 200 ° C. does not fall within a predetermined range. Reliability may be reduced. When the weight average molecular weight of the (meth) acrylic acid ester-based copolymer exceeds 1,500,000, the fluidity may be lowered and the adhesion to the adherend may be lowered. A more preferable lower limit of the weight average molecular weight of the (meth) acrylic acid ester copolymer is 700,000, a more preferable upper limit is 1.4 million, a still more preferable lower limit is 800,000, and a further preferable upper limit is 1.3 million.

In addition, the weight average molecular weight of the said (meth) acrylic acid ester-type copolymer means the value measured by polystyrene conversion by the gel permeation chromatography (GPC) method. Specifically, for example, a 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, The weight average molecular weight of the (meth) acrylic acid ester copolymer can be determined by GPC measurement using a trade name “2690 Separations Model” manufactured by Waters Co., Ltd.

The method for producing the (meth) acrylic acid ester copolymer is not particularly limited, and examples thereof include a method in which a mixed monomer containing each of the above monomers is radically polymerized in the presence of a polymerization initiator. .
The said polymerization method is not specifically limited, For example, conventionally well-known polymerization methods, such as solution polymerization, emulsion polymerization, suspension polymerization, block polymerization, are mentioned. Of these, solution polymerization is preferred.
The solvent used for the solution polymerization is not particularly limited, and examples thereof include ethyl acetate, toluene, dimethyl sulfoxide, ethanol, acetone, diethyl ether and the like.

Although the compounding quantity of the solvent used for the said solution polymerization is not specifically limited, The preferable minimum with respect to 100 weight part of said mixed monomers is 25 weight part, and a preferable upper limit is 300 weight part.

The said polymerization initiator is not specifically limited, For example, a persulfate, an organic peroxide, an azo compound etc. are mentioned. Of these, organic peroxides or azo compounds are preferred.
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-butylperoxypivalate , Lauroyl peroxide, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexa Noate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate and the like. 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, The preferable minimum with respect to 100 weight part of said mixed monomers is 0.02 weight part, and a preferable upper limit is 0.5 weight part.

The pressure-sensitive adhesive composition preferably contains a crosslinking agent. By containing the crosslinking agent, a crosslinked structure can be formed in the (meth) acrylic acid ester copolymer. Moreover, the gel fraction of the adhesive obtained can be adjusted to a predetermined range by adjusting the kind or quantity of the said crosslinking agent suitably.

The said crosslinking agent is not specifically limited, For example, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy-type crosslinking agent, a metal chelate type crosslinking agent etc. are mentioned. Among them, an isocyanate-based crosslinking agent and / or an epoxy-based crosslinking agent is preferable because performances such as heat resistance and durability are easily exhibited.

Although the said isocyanate type crosslinking agent is not specifically limited, An aliphatic isocyanate type crosslinking agent is preferable. Among the aliphatic isocyanate-based crosslinking agents, examples of commercially available products include Coronate HX (manufactured by Nippon Polyurethane Co., Ltd.), Mytec NY260A (manufactured by Mitsubishi Chemical Corporation), and the like.
Although the said epoxy-type crosslinking agent is not specifically limited, An aliphatic epoxy-type crosslinking agent is preferable. Among the above aliphatic epoxy crosslinking agents, commercially available products include, for example, Denacol EX212, Denacol EX214 (all manufactured by Nagase ChemteX), E-5C (manufactured by Soken Chemical Co., Ltd.), and other epoxy-based crosslinkings. Examples of the agent include E-AX (manufactured by Soken Chemical Co., Ltd.).

Although the compounding quantity of the said crosslinking agent is not specifically limited, The preferable minimum with respect to 100 weight part of said (meth) acrylic acid ester type copolymers is 0.01 weight part, and a preferable upper limit is 10 weight part. The more preferable lower limit of the blending amount of the crosslinking agent is 0.1 parts by weight, and the more preferable upper limit is 3.0 parts by weight.

The pressure-sensitive adhesive composition contains an ultraviolet absorber. Silver nanomaterials have a strong absorption band (surface plasmon absorption) from ultraviolet to visible light, and it is said that a strong absorption band brings about a change in resistance. UV absorbers have an absorption band between the wavelength range of 330 nm to 450 nm. Therefore, when the transparent adhesive tape of the present invention containing an ultraviolet absorber is used for bonding a touch panel, the adhesive layer absorbs ultraviolet rays and the deterioration of the transparent metal thin film with respect to the silver nanomaterial can be prevented.

The said ultraviolet absorber is not specifically limited, For example, a benzotriazole type ultraviolet absorber, a triazine type ultraviolet absorber, a hydroxyphenyl triazine type ultraviolet absorber, a benzophenone type ultraviolet absorber, a benzoate type ultraviolet absorber, etc. are mentioned. Specific examples include benzotriazole ultraviolet absorbers such as TINUVIN477 and TINUVIN328 (both manufactured by BASF Japan).

Although the compounding quantity of the said ultraviolet absorber is not specifically limited, The preferable minimum with respect to 100 weight part of said (meth) acrylic acid ester type copolymers is 0.01 weight part, and a preferable upper limit is 10 weight part. A more preferable lower limit of the blending amount of the absorbent is 0.1 parts by weight, and a more preferable upper limit is 3.0 parts by weight. Two or more of these ultraviolet absorbers may be used in combination. By using an absorber having a different wavelength together, ultraviolet rays can be absorbed over a wider wavelength region, and the deterioration of the transparent metal thin film can be more reliably prevented with respect to the silver nanomaterial.

The pressure-sensitive adhesive composition may contain a light stabilizer. By containing the light stabilizer, the pressure-sensitive adhesive layer can absorb ultraviolet rays and prevent deterioration of the transparent metal thin film with respect to the silver nanomaterial.

The light stabilizer is not particularly limited, and examples thereof include hindered amine-based polymer types, low-molecular types, and blend-based light stabilizers. Specific examples include hindered amine polymer type light stabilizers such as HALS123 (manufactured by ADEKA).

Although the compounding quantity of the said light stabilizer is not specifically limited, The preferable minimum with respect to 100 weight part of the said (meth) acrylic acid ester-type copolymer is 0.01 weight part, and a preferable upper limit is 5 weight part. The more preferable lower limit of the blending amount of the stabilizer is 0.1 parts by weight, and the more preferable upper limit is 3.0 parts by weight. Two or more of these light stabilizers may be used in combination.

The said adhesive composition may contain a rust preventive agent. Even when the transparent adhesive tape of the present invention is used for laminating a touch panel by containing a rust preventive agent, the adhesive layer is in direct contact with the silver nanomaterial of the film with the transparent metal thin film made of the silver nanomaterial. Deterioration of the transparent metal thin film can be prevented.

The rust preventive is not particularly limited, for example, sulfur-containing compounds such as thiourea, ethylenethiourea, diethylthiourea, dibutylthiourea thiourea derivatives, dicyclohexylammonium nitrite, diisopropylammonium nitrite, amine salts, lower fatty acids, and these Conventionally known rust preventives such as salts, ethylandiaminetetraacetic acid, gluconic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid and sodium citrate can be used. Among them, two or more kinds may be mixed. In addition to these, mercaptobenzothiazole, (2-benzothiazolylthio) acetic acid, 3- (2-benzothiazolylthio) propionic acid, and lithium, sodium, potassium, ammonia, amine, etc. When salt is used in combination, the rust prevention effect is further enhanced. Examples of the sulfur-containing compound include toluene dithiol, dimercaptopropanol, thioglycolic acid, potassium ethylxanthate, sodium diethyldithiocarbamate, dithizone, and diethyldithiophosphoric acid. Further, tetraphenylporphyrin, crown ether, ethylenediamine N, N-bismethylenephosphonic acid, ethylenediaminetetrakismethylenephosphonic acid, nitrilotrismethylenephosphonic acid, hydroxyethylidene diphosphonic acid and the like may be used in combination.

Although the compounding quantity of the said rust preventive agent is not specifically limited, The preferable minimum with respect to 100 weight part of the said (meth) acrylic acid ester-type copolymer is 0.01 weight part, and a preferable upper limit is 10 weight part. When the blending amount of the rust inhibitor is less than 0.01 parts by weight, the rust preventive curing with respect to the silver nanometal becomes insufficient, and when the blending amount of the rust inhibitor exceeds 10 parts by weight, the pressure-sensitive adhesive layer is obtained. In some cases, the adhesive force to the adherend is lowered, and the reliability is lowered. A more preferred lower limit of the rust inhibitor is 0.05 parts by weight, and a more preferred upper limit is 5.0 parts by weight.

The pressure-sensitive adhesive composition 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 of two or more. Of these, a xylene resin is preferable, and an alkylphenol reaction product of the xylene resin is more preferable.
Moreover, as the tackifying resin, a hydrogenated resin is preferable, and the transparency of the obtained pressure-sensitive adhesive layer is increased by using such a hydrogenated resin.

The pressure-sensitive adhesive composition preferably further contains a silane coupling agent.

The silane coupling agent is not particularly limited. For example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane Γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-amino Propyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethylmethoxysilane, N- (2-aminoethyl) 3-aminopropyltriethoxysilane, N- (2-aminoethyl) 3-aminopropylme Dimethoxysilane, .gamma.-mercaptopropyltrimethoxysilane, .gamma.-mercaptopropyl triethoxy silane, mercaptopropyl butyl trimethoxysilane, .gamma.-mercaptopropyl methyl dimethoxy silane, and the like. Of these, epoxy group-containing silane coupling agents are preferred.

Although the compounding quantity of the said silane coupling agent is not specifically limited, The preferable minimum with respect to 100 weight part of said (meth) acrylic acid ester-type copolymers is 0.01 weight part, and a preferable upper limit is 5 weight part. The more preferable lower limit of the compounding amount of the silane coupling agent is 0.05 parts by weight, and the more preferable upper limit is 3 parts by weight.

The said adhesive composition may contain conventionally well-known additives, such as a filler, as needed within the range which does not inhibit the effect of this invention.

The method for producing the pressure-sensitive adhesive composition is not particularly limited. For example, the (meth) acrylic acid ester copolymer, and the cross-linking agent to be added as necessary, the tackifier resin, and the silane coupling are used. The method of mixing and stirring an agent, the said additive, etc. is mentioned.

Although the thickness of the said adhesive layer of the transparent adhesive tape of this invention is not specifically limited, A preferable minimum is 5 micrometers and a preferable upper limit is 1 mm. When the thickness of the pressure-sensitive adhesive layer is less than 5 μm, the pressure-sensitive adhesive layer may be less reliable due to a decrease in the adhesive force to the adherend. When the thickness of the pressure-sensitive adhesive layer exceeds 1 mm, the pressure-sensitive adhesive component oozes out and the handleability may deteriorate. A more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 10 μm, a further preferable lower limit is 20 μm, a more preferable upper limit is 500 μm, and a further preferable upper limit is 300 μm.

The non-support type which does not have a base material may be sufficient as the transparent adhesive tape of this invention, and the support type in which the adhesive layer was formed on both surfaces of the base material may be sufficient.
The base material is not particularly limited as long as it is a transparent base material. For example, the base material is made of a transparent resin such as acrylic, olefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), nylon, urethane, and polyimide. Examples thereof include a sheet, a sheet having a network structure, and a sheet having holes.

Although the thickness of the said base material is not specifically limited, A preferable minimum is 2 micrometers and a preferable upper limit is 200 micrometers. If the thickness of the substrate is less than 2 μm, the strength of the transparent adhesive tape obtained may be insufficient, and it may be torn or difficult to handle. When the thickness of the base material exceeds 200 μm, the base material is too strong, and the followability to the step of the transparent adhesive tape obtained may be deteriorated. A more preferable lower limit of the thickness of the substrate is 5 μm, and a more preferable upper limit is 100 μm.

The method for producing the transparent adhesive tape of the present invention is not particularly limited. As a method for producing a non-support type transparent pressure-sensitive adhesive tape, for example, a pressure-sensitive adhesive layer is formed by coating the pressure-sensitive adhesive composition on a release-treated surface of a release paper or a release film, and the resulting pressure-sensitive adhesive is obtained. On the layer, a newly prepared release paper or release film is laminated so that the release treatment surface is in contact with the pressure-sensitive adhesive layer to obtain a laminate, and then the obtained laminate is pressed with a rubber roller or the like. Methods and the like.

In addition, as a method for producing the transparent adhesive tape of the present invention, a mixed monomer containing each of the above monomers, which is a raw material for the (meth) acrylic acid ester copolymer, is radically polymerized by bulk polymerization, and the above (meta) ) A method of producing an acrylic ester copolymer and tapering at the same time can also be used.

The bulk polymerization is preferably photopolymerization because the heat of polymerization is easily removed and the reaction is easily controlled.
In particular, as a method for producing the transparent adhesive tape of the present invention, a monomer composition containing the above mixed monomer, photopolymerization initiator, and, if necessary, an additive and the like and containing no solvent, Is applied to the release treatment surface of a transparent synthetic resin film which has been subjected to a release treatment to form a monomer layer, and then another transparent synthetic resin film whose one surface has been release treatment on the monomer layer A method of radical polymerization of the mixed monomer is preferably used by overlaying the mold release treatment surfaces and passing the synthetic resin film through light irradiation such as ultraviolet irradiation through the monomer layer. However, when photopolymerization is performed in the presence of an ultraviolet absorber such as benzotriazole, a (meth) acrylic ester copolymer having a high molecular weight may not be obtained due to polymerization inhibition. Therefore, when the polymerization is carried out in the presence of an ultraviolet absorber, it is preferable to adopt means other than photopolymerization such as solution polymerization.
In addition, the said transparent synthetic resin film is not specifically limited, For example, a polyethylene terephthalate film etc. are mentioned.

When the transparent adhesive tape of the present invention is produced by photopolymerization, the mixed monomer contains a polyfunctional (meth) acrylate having two or more polymerizable functional groups because a crosslinked structure can be formed simultaneously with the polymerization. It is preferable to do.
The polyfunctional (meth) acrylate is not particularly limited. For example, 1,6-hexanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate, hydrogenated polybutadiene Examples include di (meth) acrylate, trimethylolpropane triacrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, polyurethane di (meth) acrylate, and polyester di (meth) acrylate. Among them, 1,6-hexanediol diacrylate, polypropylene glycol diacrylate, hydrogenated polybutadiene diacrylate, polyurethane diacrylate, and polyester diacrylate are preferred because the pressure dispersion of the resulting pressure-sensitive adhesive layer is small and excellent in adhesive performance. Is preferred.

When the said mixed monomer contains the said polyfunctional (meth) acrylate, the compounding quantity of the said polyfunctional (meth) acrylate is not specifically limited, The preferable minimum in the said mixed monomer is 0.02 weight%, A preferable upper limit is 5 % By weight. When the blending amount of the polyfunctional (meth) acrylate is less than 0.02% by weight, the (meth) acrylic acid ester copolymer is insufficiently crosslinked, and the resulting pressure-sensitive adhesive layer has reduced cohesive force. As a result, workability may be reduced. When the blending amount of the polyfunctional (meth) acrylate is more than 5% by weight, the pressure-sensitive adhesive layer obtained may have reduced adhesive strength and initial adhesiveness to the adherend, resulting in reduced reliability.
As for the compounding quantity of the said polyfunctional (meth) acrylate, the more preferable minimum in the said mixed monomer is 0.05 weight%, and a more preferable upper limit is 3 weight%.

The photopolymerization initiator is not particularly limited. For example, ketone photopolymerization such as 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone (trade name “Darocur 2959” manufactured by Merck & Co., Inc.). Initiator, α-hydroxy-α, α′-dimethyl-acetophenone (Merck, trade name “Darocur 1173”), methoxyacetophene, 2,2-dimethoxy-2-phenylacetophene (Ciba Geigy, trade name) "Irgacure 651"), 2-hydroxy-2-cyclohexylacetophenone (product name "Irgacure 184" manufactured by Ciba Geigy), etc., ketal photopolymerization initiators such as benzyldimethyl ketal, halogenated ketones , Acyl phosphinoxide, acyl phosphonate and the like.

Although the compounding quantity of the said photoinitiator is not specifically limited, The preferable minimum with respect to 100 weight part of said mixed monomers is 0.01 weight part, and a preferable upper limit is 5 weight part. When the blending amount of the photopolymerization initiator is less than 0.01 parts by weight, the polymerization of the mixed monomer becomes incomplete, and the obtained pressure-sensitive adhesive layer has the necessary physical properties due to a decrease in cohesive force. It may not be possible. If the blending amount of the photopolymerization initiator exceeds 5 parts by weight, the amount of radicals generated during light irradiation increases, the number average molecular weight of the resulting acrylic copolymer decreases, or the gel fraction of the pressure-sensitive adhesive layer decreases. As a result, whitening of the pressure-sensitive adhesive layer that occurs under high temperature and high humidity may not be sufficiently suppressed.
As for the compounding quantity of the said photoinitiator, the more preferable minimum with respect to 100 weight part of said mixed monomers is 0.03 weight part, and a more preferable upper limit is 1 weight part.

The lamp used for the light irradiation is not particularly limited, and examples thereof include a lamp having a light emission distribution at a wavelength of 400 nm or less.
Examples of the lamp having a light emission distribution at a wavelength of 400 nm or less include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp. It is done. Among these, the light in the active wavelength region of the photopolymerization initiator is efficiently emitted, and there is little light absorption of components other than the photopolymerization initiator contained in the monomer layer, so that light can enter the monomer layer. A chemical lamp is preferred because it can sufficiently reach and effectively polymerize the mixed monomer.

The light irradiation intensity in the above light irradiation is not particularly limited, and is a factor that affects the degree of polymerization of the obtained acrylic copolymer, so that it matches the degree of polymerization of the target allyl copolymer or the performance of the pressure-sensitive adhesive layer. And adjusted as appropriate.
For example, when an acetophenone photopolymerization initiator is used as the photopolymerization initiator, the light irradiation intensity in the wavelength region effective for photolysis of the acetophenone photopolymerization initiator is 0.1 to 100 mW / cm ² . It is preferable. The effective wavelength region for the photodecomposition of the acetophenone photopolymerization initiator is usually about 365 nm to 420 nm, although it varies depending on the photopolymerization initiator.

If the transparent adhesive tape of this invention is used, even when it sticks directly with respect to the transparent metal thin film surface of the film with a transparent metal thin film which consists of silver nanomaterials, deterioration of a transparent metal thin film can be suppressed.
The silver nanomaterial is a silver material contained in the conductive ink printed on the film, and is contained in the ink in addition to the binder resin, the dispersant, etc., and the silver nanowire or silver nanohaving a diameter of about 10 to 1000 nm. There are particles. The silver nanomaterial may be silver alone or an alloy of silver and another metal. Examples of the metal used in the alloy with silver include platinum, osmium, palladium, iridium, tin, bismuth, and nickel. These may be used alone or in combination of two or more. If the transparent adhesive tape of this invention is used, degradation of the silver nanomaterial which consists of an alloy of silver and silver and another metal can be suppressed especially among silver nanomaterials. The film with a transparent metal thin film can be obtained by printing the conductive ink on the film.

The transparent adhesive tape of the present invention is a laminate in which a polycarbonate plate and a transparent metal thin film surface of a film with a metal thin film are bonded together, a laminate in which an acrylic plate and a transparent metal thin film surface of a film with a metal thin film are bonded together, or The number of bubbles having a diameter of 10 μm or more generated after leaving the laminated body in which the transparent metal thin film surfaces of two films with a metal thin film are bonded together in an environment of a temperature of 85 ° C. and a relative humidity of 85% for 240 hours is zero. It is preferable that it is a piece.

The transparent adhesive tape of the present invention has a resistance value of the metal thin film after being left in an environment of 85 ° C. and 85% relative humidity for 240 hours after being bonded to the transparent metal thin film surface of the film with the metal thin film. In comparison, it is preferably within ± 10%.

The transparent adhesive tape of the present invention is a laminate in which a polycarbonate plate and a metal thin film surface of a film with a metal thin film are bonded together, a laminate in which an acrylic plate and a metal thin film surface of a film with a metal thin film are bonded together, or two sheets The haze value 20 minutes after taking out the laminated body in which the transparent metal surfaces of the film with the metal thin film are bonded together in an environment of a temperature of 85 ° C. and a relative humidity of 85% for 240 hours is compared with that before leaving. Is preferably within ± 1%.

The use of the transparent adhesive tape of the present invention is not particularly limited, but when manufacturing an image display device such as a mobile phone or a portable information terminal, a cover panel for protecting the surface and a touch panel module are bonded, or the cover panel And a display panel module, or a touch panel module and a display panel module can be suitably used. In particular, it is suitable when the cover panel is a polycarbonate plate or an acrylic plate.
Cover panel in which the cover panel and the touch panel module are bonded via the transparent adhesive tape of the present invention-Touch panel module laminate, and cover panel in which the cover panel and the display panel module are bonded via the transparent adhesive tape of the present invention- A touch panel module-display panel module laminate in which the touch panel module and the display panel module are bonded is obtained through the display panel module laminate and the transparent adhesive tape of the present invention.

The transparent adhesive tape of the present invention can also be suitably used for bonding two films with a metal thin film.
A film laminate with a metal thin film obtained by laminating two films with a metal thin film through the transparent adhesive tape of the present invention is obtained.
An image display device having a film laminate with a silver nanowire film, a cover panel-touch panel module laminate of the present invention, a cover panel-display panel module laminate of the present invention, or a touch panel module-display panel module laminate of the present invention. can get.

ADVANTAGE OF THE INVENTION According to this invention, this invention can provide the transparent adhesive tape which can suppress deterioration of the transparent metal thin film which consists of silver nanomaterials.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
(1) Production of (meth) acrylic acid ester copolymer In a reactor equipped with a thermometer, a stirrer and a condenser, 8 parts by weight of methyl methacrylate, 84 parts by weight of n-butyl acrylate, and 8 parts of methyl acrylate 60 parts by weight of ethyl acetate was added to 100 parts by weight of the monomer mixture consisting of parts by weight, and after nitrogen substitution was performed by blowing nitrogen gas for 30 minutes, the reactor was heated to 70 ° C. After 30 minutes, 0.12 parts by weight of t-hexyl peroxypivalate as a polymerization initiator was diluted with 40 parts by weight of ethyl acetate with respect to 100 parts by weight of the monomer, and the resulting polymerization initiator solution was subjected to the above reaction. It was added dropwise to the vessel over 5 hours. Then, it was made to react at 70 degreeC for 8 hours from the start of addition of a polymerization initiator, and the (meth) acrylic acid ester type copolymer solution of 50% of solid content was obtained.

(2) Manufacture of transparent adhesive tape In the obtained (meth) acrylic acid ester copolymer solution, with respect to 100 parts by weight of solid content of (meth) acrylic acid ester copolymer, isocyanate curing as a curing agent Agent (L-45, manufactured by Soken Chemical Co., Ltd.) 0.3 parts by weight in terms of solid content, and silane coupling agent KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight in terms of solids, UV absorber TINUVIN 477 (manufactured by BASF Japan) 0.2 parts by weight, added as a rust inhibitor BTA (1H-benzotriazole, manufactured by Wako Pure Chemical Industries, Ltd.) and stirred to prepare an adhesive composition .

The obtained pressure-sensitive adhesive composition was applied to the release-treated surface of the release polyethylene terephthalate film, dried at 80 ° C. for 5 minutes, and further dried at 110 ° C. for 3 minutes to obtain a solution in the pressure-sensitive adhesive composition solution. A release polyethylene terephthalate film prepared by removing ethyl acetate to form a pressure-sensitive adhesive layer having a thickness of 50 μm and further having a release-treated surface in contact with the pressure-sensitive adhesive layer on the obtained pressure-sensitive adhesive layer. Were stacked to obtain a laminate. By pressing the obtained laminate with a rubber roller, a transparent adhesive tape having a release polyethylene terephthalate film attached to both surfaces was obtained.

(4) Measurement of gel fraction of pressure-sensitive adhesive layer The obtained transparent adhesive tape having a thickness of 100 μm was cut into a flat rectangular shape of 50 mm × 25 mm to produce a test piece, and the weight W ₁ of the produced test piece was measured. did. After immersing the test piece in ethyl acetate at 23 ° C. for 24 hours, the test piece was taken out from ethyl acetate using a 200-mesh stainless steel mesh and dried at 110 ° C. for 1 hour. The weight W ₂ after drying the test piece was measured to calculate the gel fraction by the following equation.

Gel fraction (% by weight) = 100 × (W ₂ −W ₀ ) / (W ₁ −W ₀ )
In the formula, W ₀ represents the weight of the substrate, W ₁ represents the weight of the test piece before dipping, and W ₂ represents the weight of the test piece after dipping and drying. When the transparent adhesive tape does not have a substrate, W ₀ = 0.

(Examples 2 to 6 )
The ultraviolet absorbent was obtained in the same manner as in Example 1 (meth) acrylate copolymer and a transparent adhesive tape except for changing the amount described in Table 1. Further, the gel fraction was measured in the same manner as in Example 1.

(Examples 8 to 12)
The type and amount of the ultraviolet absorber was obtained except for changing the street in the same manner as in Example 1, (meth) acrylic acid ester copolymer and a transparent pressure-sensitive adhesive tape according to Table 2. Further, the gel fraction was measured in the same manner as in Example 1. In addition to changing only the kind and compounding quantity of the ultraviolet absorber only in Example 12, the curing agent was changed from 0.3 parts by weight to 0.4 parts by weight in terms of solid content.

(Comparative Example 1)
A (meth) acrylic acid ester copolymer in the same manner as in Example 1 except that the types and blending amounts of the ultraviolet absorber , light stabilizer, additive, rust inhibitor, and curing agent are as shown in Table 1. And the transparent adhesive tape was obtained.

(Example 13)
(1) Production of (meth) acrylic acid ester copolymer In a reactor equipped with a thermometer, a stirrer and a cooling tube, 29 parts by weight of 2-ethylhexyl acrylate, 30.6 parts by weight of isobornyl acrylate, n -Add 60 parts by weight of ethyl acetate to 100 parts by weight of a monomer mixture consisting of 21 parts by weight of butyl acrylate, 19 parts by weight of 2-hydroxyethyl acrylate and 0.4 parts by weight of acrylic acid, and blow nitrogen gas for 30 minutes. After purging with nitrogen, the reactor was heated to 70 ° C. After 30 minutes, 0.12 parts by weight of t-hexyl peroxypivalate as a polymerization initiator was diluted with 40 parts by weight of ethyl acetate with respect to 100 parts by weight of the monomer, and the resulting polymerization initiator solution was subjected to the above reaction. It was added dropwise to the vessel over 5 hours. Then, it was made to react at 70 degreeC for 8 hours from the start of addition of a polymerization initiator, and the (meth) acrylic acid ester type copolymer solution of 50% of solid content was obtained.

(2) Manufacture of transparent adhesive tape In the obtained (meth) acrylic acid ester copolymer solution, 100% by weight of the solid content of the (meth) acrylic acid ester copolymer, Maitec NY260A as a curing agent (Mitsubishi Chemical Co., Ltd.) 1 part by weight in terms of solid content, KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, 1 part by weight in terms of solid content, TINUVIN 328 (manufactured by BASF Japan) ) It was added to 2 parts by weight and stirred to prepare an adhesive composition.
The obtained pressure-sensitive adhesive composition was processed in the same manner as in Example 1 to obtain a transparent pressure-sensitive adhesive tape having a release polyethylene terephthalate film attached to both sides. Further, the gel fraction was measured in the same manner as in Example 1.

(Examples 14 to 18)
A (meth) acrylic acid ester copolymer in the same manner as in Example 13 except that the types and blending amounts of the ultraviolet absorber , light stabilizer, additive, rust inhibitor, and curing agent were as shown in Table 3. And the transparent adhesive tape was obtained. Further, the gel fraction was measured in the same manner as in Example 1 .

(Comparative Example 2)
(Meth) acrylate ester copolymer in the same manner as in Example 13 except that no ultraviolet absorber was blended and the curing agent was changed from 1 part by weight to 0.4 parts by weight in terms of solid content. And the transparent adhesive tape was obtained.

(Evaluation)
The following evaluation was performed about the transparent adhesive tape and film laminated body which were obtained by the Example and the comparative example. The results are shown in Table 1, Table 2 and Table 3.

Resistivity change rate under simulated outdoor environment (xenon weather)
The obtained transparent adhesive tape having a thickness of 50 μm was cut so as to have a planar shape of 45 mm × 60 mm. One release polyethylene terephthalate film of the cut transparent adhesive tape is peeled off, and the exposed surface of the transparent adhesive tape is pasted on a touch panel module having a thickness of 0.18 mm (a film with a silver nanowire film having a thickness of 0.18 mm). Combined. Further, the other release polyethylene terephthalate film of the transparent adhesive tape is peeled off, and the exposed surface of the transparent adhesive tape is bonded to a polycarbonate plate (PC plate) having a planar shape with a thickness of 1 mm to thereby obtain a polycarbonate plate ( A module laminate in which a transparent adhesive tape and a touch panel module are laminated in this order on a (PC board) was obtained.

Then, it exposed to the light of the lamp for 500 hours at 23 degreeC using the xenon lamp of the irradiation intensity | strength of 180 W / m < ² >. For the measurement, “Xenon Weather Meter” manufactured by Suga Test Co., Ltd. was used. The initial resistance value (Ω) before being exposed to the xenon lamp and the resistance value after being exposed to the lamp light for 500 hours were measured by the four-terminal method.
The measurement of the resistance value is performed between the terminal and the terminal with respect to the exposed portion of the silver nanowire gold film surface to which the transparent adhesive tape is not applied on the silver nanowire film surface of the film with silver nanowires. The resistance value was measured by applying a terminal of a two-terminal resistance value measuring device so that the transparent adhesive tape was blocked.
The rate of increase in resistance was determined by the following method.
Resistance increase rate = (resistance value after 500 hours / initial resistance value) × 100
The case where the resistance increase rate was 150% or less was evaluated as good, and the case where the resistance increase rate was 120% or less was evaluated as better.

Claims (3)

A transparent conductive film having a metal conductive pattern containing a silver nanomaterial on a transparent film substrate, and a transparent acrylic film containing an ultraviolet absorber laminated on the surface of the transparent conductive film on the metal conductive pattern side A patterned electrode sheet formed from an adhesive. 2. The patterned electrode sheet according to claim 1, wherein the transparent acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive containing 0.01 to 10 parts by weight of an ultraviolet absorber with respect to 100 parts by weight of the acrylic polymer. A transparent conductive film having a metal conductive pattern containing a silver nanomaterial on a transparent film substrate, and a transparent acrylic film containing an ultraviolet absorber laminated on the surface of the transparent conductive film on the metal conductive pattern side A transparent acrylic pressure-sensitive adhesive used for a patterned electrode sheet formed from a pressure-sensitive adhesive, which is a pressure-sensitive adhesive containing 0.01 to 10 parts by weight of an ultraviolet absorber with respect to 100 parts by weight of an acrylic polymer. Transparent acrylic adhesive.