JP2012201803A - Method for producing adhesive composition, adhesive composition, and adhesive tape using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an adhesive composition for an adhesive tape to be adhered to an ITO surface of a transparent conductive laminate having a transparent conductive film, capable of suppressing change in resistance value of the transparent conductive film and preventing a white turbidity from being produced after an environmental test at high temperature and high humidity, an adhesive composition, and an adhesive tape using the same.SOLUTION: The method for producing an adhesive composition for an adhesive tape to be adhered to the ITO surface of the transparent conductive film including ITO includes at least following steps (1) and (2) to obtain the adhesive composition. (1) the step of adjusting an adhesive raw material mixture obtained by mixing, to a pressure-sensitive adhesive composition including an acrylic resin, at least one monomer of a hydroxyl-containing (meth)acrylate and a photopolymerization initiator. (2) The step of performing polymerization reaction by light irradiation using the adhesive composition raw material mixture to produce the adhesive composition.

Description

  The present invention provides an ITO surface of a transparent conductive laminate in which a transparent conductive film (hereinafter sometimes referred to as ITO) made of ITO (abbreviation of indium tin oxide) is formed on the surface of a transparent substrate. The present invention relates to an adhesive tape to be bonded. More specifically, a method for producing an adhesive composition for an adhesive tape that suppresses a change in the resistance value of the transparent conductive film and does not cause white turbidity in the adhesive layer after an environmental test at high temperature and high humidity, and an adhesive composition The present invention relates to providing an article and an adhesive tape using the article.

In recent years, transparent conductive laminates in which an ITO thin film is formed as a transparent conductive film on one surface of a transparent substrate made of a transparent resin film or a glass plate have been widely used in various applications.
As a use of a transparent conductive laminated body, the transparent electrode etc. which are used for a touch panel, a liquid crystal display, an organic EL display, a solar cell etc. are mentioned, for example.
Since the present invention relates to a transparent conductive laminate, a technical background up to the completion of the present invention will be described below using a touch panel in which the transparent conductive laminate is used as an example.

In the touch panel in which the transparent conductive laminate is incorporated as a member, various improvements have been conventionally made for improving the operability and durability of the touch panel. For example, a surface protective film that is used by being attached to the surface of a touch panel for preventing damage or deterioration of the surface of the touch panel has been proposed. (For example, see Patent Documents 1 and 2.)
Conventionally, as a transparent conductive laminate used for general touch panels, a hard coat film in which a hard coat layer is formed on one side of a substrate made of a transparent resin film, and a transparent conductive film is formed on one side of a transparent substrate. The surface of the hard coat film on which the hard coat layer is not formed and the surface of the transparent conductive laminate on which the transparent conductive film is not formed are opposed to each other through the adhesive. A transparent conductive laminate (a so-called bonded transparent conductive laminate) that has been bonded together is known.

  However, in recent years, with the expansion of the use of transparent conductive laminates, cost reduction has been demanded. In addition to the conductive performance and ease of use of transparent conductive laminates, There is a need to reduce the thickness of the entire transparent conductive laminate by reduction or the like. As one of the methods for solving these problems, one transparent base material and pressure-sensitive adhesive layer are omitted from the member configuration of the bonded transparent conductive laminate. As a result, by forming a transparent conductive laminate in which a conductive thin film is formed on one side of a transparent substrate and a hard coat layer is formed on the other side, the entire transparent conductive laminate can be reduced in thickness and cost can be reduced. It has been.

About a transparent conductive laminated body, the protective film bonded together on a transparent conductive film layer and utilized for protection of a transparent conductive film is also shown. (For example, see Patent Document 3)
In recent years, touch panels, which are optical devices using a transparent conductive laminate, have been required to further improve the finished appearance and dimensional accuracy when manufactured. Further, in the process of manufacturing an optical element or an optical device incorporating the transparent conductive laminate, the pressure-sensitive adhesive layer of the adhesive tape bonded onto the transparent conductive film is the surface resistance of the transparent conductive film of the transparent conductive laminate. It is required that the rate change is suppressed, and that the cloudiness does not occur in the pressure-sensitive adhesive layer even after an environmental test at high temperature and high humidity.
For this reason, the pressure-sensitive adhesive sheet, pressure-sensitive adhesive tape, and pressure-sensitive adhesive composition used for bonding optical components should not be turbid even in an environmental test at high temperatures and high humidity. Efforts are being made. (For example, see Patent Documents 4 to 7.)

JP-A-8-329767 JP-A-2-068099 Japanese Patent Laid-Open No. 7-068691 JP 2007-246882 A JP 2007-161908 A JP 2008-248221 A JP 2008-001739 A

  By the way, in the process of manufacturing an optical element or an optical device incorporating a transparent conductive laminate, it is possible to use a protective film for a transparent conductive layer as disclosed in Patent Document 3 to obtain a transparent conductive laminate. It is effective because it can be processed by a roll-to-roll manufacturing process without causing damage due to heat in a heating process at 120 ° C. or higher, and without causing damage to the transparent conductive film. There is.

  However, the protective film for the transparent conductive film layer disclosed in Patent Document 3 is used in terms of preventing the transparent conductive film from being damaged in a heating step of 120 ° C. or more by using a heat resistant resin film. However, it is not useful as a solution to the problem that the surface resistivity of the transparent conductive film changes in the process of processing into an optical element or optical device using the transparent conductive laminate.

Further, Patent Document 4 discloses that the amount of gas that causes malfunction of the electronic member is small, the precision electronic member is not corroded and the appearance is not deteriorated, and adhesive physical properties, particularly adhesion to metal and tackiness. A resin composition having excellent strength, in particular, a resin composition for pressure-sensitive adhesive, a pressure-sensitive adhesive composition using the same, and a pressure-sensitive adhesive sheet are disclosed. The pressure-sensitive adhesive sheet shown in Patent Document 4 uses an acrylic pressure-sensitive adhesive composition that does not use acrylic acid. The pressure-sensitive adhesive sheet is bonded to a copper plate for corrosion test, and has a temperature of 60 ° C. and a humidity of 90% RH. It is said that no corrosion is observed even if the corrosion condition is determined by the presence or absence of discoloration of the copper plate after being left for 7 days under environmental conditions.
However, Patent Document 4 does not describe that no white turbidity occurs in the pressure-sensitive adhesive layer after an environmental test at high temperature and high humidity, and is not useful as a solution to the problem that white turbidity occurs in the pressure-sensitive adhesive layer. It is.

  Further, in Patent Document 5, it can be easily peeled off even when used as an adhesive composition for a full surface filter to be bonded to the entire surface of a PDP (plasma display), and it is cloudy even in a high temperature and high humidity environment. A photopolymerizable pressure-sensitive adhesive composition that is less likely to cause oxidization and a pressure-sensitive adhesive sheet using the same are disclosed. However, in Patent Document 5, there is no description that the change in the surface resistivity of the transparent conductive film is not adversely affected when bonded to the ITO surface. Moreover, although the Example of patent document 5 contains 4 weight% of acrylic acid in the acrylic adhesive composition effective for white turbidity prevention, the said adhesive composition affects the corrosion of the ITO surface, There is concern about increasing the surface resistivity of the ITO film.

  Patent Document 6 discloses an optical resin composition that is transparent and has an appropriate adhesive strength and shock absorption necessary for protection of an image display device and the like, and does not invade constituent materials such as a panel for an image display device. And an optical resin composition using the same are disclosed. Specifically, it is an optical resin composition containing an acrylic acid derivative, an acrylic acid derivative polymer, and a high molecular weight crosslinking agent. However, Patent Document 6 does not describe that no white turbidity occurs in the pressure-sensitive adhesive layer after an environmental test at high temperature and high humidity, and is not useful as a solution to the problem that white turbidity occurs in the pressure-sensitive adhesive layer. It is.

  Patent Document 7 discloses a pressure-sensitive adhesive composition containing a copolymer and / or a mixture of a (meth) acrylic acid alkyl ester monomer and a carboxyl group-containing monomer under an environment at high temperature and high humidity. However, a pressure-sensitive adhesive layer for electronic displays that does not cause white turbidity is disclosed. However, in Patent Document 7, there is no description that when bonded to the ITO surface, the change in surface resistivity of the transparent conductive film is not adversely affected, and the adhesive composition is bonded to the ITO surface. Whether it can be used is unknown.

  As described above, in the prior art, in the adhesive tape for the transparent conductive film layer used for the transparent conductive laminate, the change in the surface resistance value of the transparent conductive film is prevented, and after the environmental test at high temperature and high humidity, An adhesive tape that does not cause white turbidity has not been known.

  That is, an object of the present invention is to suppress a change in the resistance value of the transparent conductive film in the adhesive tape bonded to the ITO surface of the transparent conductive laminate in which the transparent conductive film is formed, and at high temperature and high humidity. It is providing the manufacturing method of the adhesive composition of the adhesive tape which does not produce white turbidity after an environmental test, an adhesive composition, and an adhesive tape using the same.

In order to prevent water molecules from agglomerating due to sudden changes in the external environment and prevent the adhesive layer from becoming cloudy, the present invention suppresses changes in the resistance value of the transparent conductive film even when bonded to the ITO surface. A pressure-sensitive adhesive composition consisting of an acrylic polymer having an acid value of 0 to 33, which can be used as it is as a pressure-sensitive adhesive, is cross-linked with a monomer having a hydroxyl group to disperse water molecules invisible. The technical idea is to obtain a pressure-sensitive adhesive composition having an enhanced function by adding a new function of existing in a state of being added.
That is, in the present invention, at least one kind of a hydroxyl group-containing (meth) acrylate monomer is crosslinked and introduced into a pressure-sensitive adhesive composition comprising an acrylic polymer having an acid value of 0 to 33. To prevent water molecules from aggregating. By doing so, even when bonded to the adherend ITO, the change in resistance value of the transparent conductive film is suppressed, and the adhesive layer does not become cloudy after an environmental test at high temperature and high humidity An adhesive composition for a tape and an adhesive tape using the same can be provided.

Then, in order to solve the said problem, in this invention, it is a manufacturing method of the adhesive composition of the adhesive tape bonded on this ITO surface of the transparent conductive film which consists of ITO, Comprising: At least following (1 ) To (2), a pressure-sensitive adhesive composition (polymer C) having physical properties (K) is obtained.
(1) A pressure-sensitive adhesive composition (polymer A) made of an acrylic resin having an acid value of 0 to 33, at least one monomer (monomer B) of a hydroxyl group-containing (meth) acrylate, and photopolymerization A step of preparing a raw material mixture for an adhesive obtained by mixing an initiator.
(2) The process of obtaining the adhesive composition (polymer C) which has a physical property (K) by making the polymerization reaction by light irradiation using the said raw material mixture for adhesives.
Physical Properties (K): After applying a pressure-sensitive adhesive composition (Polymer C) on the ITO surface to form a thin film having a thickness of 200 μm after drying, 500 hours of execution was performed in an environment of temperature 85 ° C. × humidity 85% RH. After taking out from the oven for high-temperature and high-humidity environmental testing, the resistance value change magnification of the ITO film is 1.7 times or less compared to the initial value, and the pressure-sensitive adhesive composition (polymer C) layer immediately after taking out from the oven There is no cloudiness.

Moreover, in this invention, it is a manufacturing method of the adhesive composition of the adhesive tape bonded by this ITO surface of the transparent conductive film which consists of ITO, Comprising: It passes through the process of following (1)-(3) at least. By this, the manufacturing method of the adhesive composition characterized by obtaining the adhesive composition (polymer C) which has a physical property (K) is provided.
(1) A pressure-sensitive adhesive composition (polymer A) made of an acrylic resin having an acid value of 0 to 33, at least one monomer (monomer B) of a hydroxyl group-containing (meth) acrylate, and photopolymerization A step of preparing a raw material mixture for an adhesive obtained by mixing an initiator.
(2) The process of apply | coating the said raw material mixture for adhesives to the base film consisting of a long thermoplastic resin so that it may become thickness 20-500 micrometers after drying, and obtaining a long coating film.
(3) A step of obtaining a pressure-sensitive adhesive composition (polymer C) having physical properties (K) on the base film by performing a polymerization reaction by light irradiation using the long coating film.
Physical Properties (K): After applying a pressure-sensitive adhesive composition (Polymer C) on the ITO surface to form a thin film having a thickness of 200 μm after drying, 500 hours of execution was performed in an environment of temperature 85 ° C. × humidity 85% RH. After taking out from the oven for high-temperature and high-humidity environmental testing, the resistance value change magnification of the ITO film is 1.7 times or less compared to the initial value, and the pressure-sensitive adhesive composition (polymer C) layer immediately after taking out from the oven There is no cloudiness.

Pressure-sensitive adhesive composition (polymer A) comprising an acrylic resin having an acid value of 0 to 33: 100 parts by weight of a solid content;
At least one monomer (monomer B) of hydroxyl group-containing (meth) acrylate: 5 to 15 parts by weight;
Photopolymerization initiator: 0.01 to 0.5 parts by weight;
A pressure-sensitive adhesive composition (Polymer C) characterized by having a physical property (K).
Physical Properties (K): After applying a pressure-sensitive adhesive composition (Polymer C) on the ITO surface to form a thin film having a thickness of 200 μm after drying, 500 hours of execution was performed in an environment of temperature 85 ° C. × humidity 85% RH. After taking out from the oven for high-temperature and high-humidity environmental testing, the resistance value change magnification of the ITO film is 1.7 times or less compared to the initial value, and the pressure-sensitive adhesive composition (polymer C) layer immediately after taking out from the oven There is no cloudiness.

  Moreover, the adhesive tape (polymer C) manufactured by said method provides the adhesive tape laminated | stacked on a base film.

  The pressure-sensitive adhesive composition (polymer C) provides a pressure-sensitive adhesive tape that is laminated on a base film.

  Moreover, this invention is suitable for the adhesive tape of the use which bonds a member to a display.

According to the present invention, the pressure-sensitive adhesive composition having an existing acid value of 0 to 33 is modified to provide a pressure-sensitive adhesive composition in which hydroxyl groups that adsorb water molecules are dispersed. Can adsorb moisture under high temperature and high humidity environmental conditions to the hydroxyl group-containing polymer, and prevent the occurrence of white turbidity due to aggregation of absorbed water molecules even if the adhesive layer is thickened to increase buffering properties The new function of being able to do so can be demonstrated.
Moreover, it is possible to thicken the coating thickness to a base material by adjusting the fluidity | liquidity of an adhesive coating liquid appropriately, and can form a thick adhesive tape and can improve buffering property.

Fig.1 (a) is sectional drawing which shows typically an example of the single-sided adhesive tape which has an adhesive layer formed using the adhesive composition of this invention, FIG.1 (b) is the adhesive of this invention. It is sectional drawing which shows typically an example of the transfer tape which has an adhesive layer formed using the composition. It is explanatory drawing which shows typically an example of the manufacturing method of the adhesive film of this invention. FIG. 3A is a graph showing a change in haze value immediately after taking out from the oven for environmental testing at high temperature and high humidity for Example 1 and Comparative Example 2, and the effect of the present invention is high temperature and high humidity. It is shown for reference that white turbidity does not occur after an environmental test at. FIG. 3B is a graph obtained by enlarging FIG. 3A in a time range of 0 to 40 minutes.

Hereinafter, preferred embodiments of the present invention will be described.
The pressure-sensitive adhesive composition (polymer C) of the present invention is a pressure-sensitive pressure-sensitive adhesive composition (polymer A) made of an acrylic resin, and at least one hydroxyl group-containing (meth) acrylate monomer (monomer B), After preparing a pressure-sensitive adhesive mixture obtained by mixing a photopolymerization initiator, a pressure-sensitive adhesive composition (K) having physical properties (K) is prepared by subjecting the pressure-sensitive adhesive mixture to a polymerization reaction by light irradiation. It can be produced by obtaining a polymer C).
Physical Properties (K): After applying a pressure-sensitive adhesive composition (Polymer C) on the ITO surface to form a thin film having a thickness of 200 μm after drying, 500 hours of execution was performed in an environment of temperature 85 ° C. × humidity 85% RH. After taking out from the oven for high-temperature and high-humidity environmental testing, the resistance value change magnification of the ITO film is 1.7 times or less compared to the initial value, and the pressure-sensitive adhesive composition (polymer C) layer immediately after taking out from the oven There is no cloudiness.

In order to produce the pressure-sensitive adhesive composition of the present invention, first, at least one hydroxyl group-containing monomer (monomer B), a polymerization initiator for polymerizing the monomer B, and a pressure-sensitive pressure-sensitive adhesive comprising an acrylic resin It mixes with an agent composition (polymer A), and prepares the raw material mixture for adhesives. This raw material mixture for pressure-sensitive adhesives contains at least one hydroxyl group-containing (meth) acrylate (monomer B) as a photopolymerizable compound that is polymerized by energy rays. Monomer B of (meth) acrylate is a polymerizable compound having a (meth) acryl group which is a vinyl group capable of radical polymerization with a photopolymerization initiator, and is cured, for example, with respect to ultraviolet rays within a range of 300 nm to 400 nm. It is an ultraviolet curable resin material having properties.
In this specification, (meth) acrylate is a general term for acrylate and methacrylate.

The polymer A is not particularly limited as long as it is a main component of the pressure-sensitive adhesive composition of the present invention, has an acid value of 0 to 33, and easily disperses an acrylic monomer (monomer B) containing a hydroxyl group.
In order to easily disperse the monomer B, an acrylic polymer is preferable, and a hydrophilic monomer is preferably copolymerized. This is because the monomer B is acrylic and contains a hydroxyl group. In addition, since the pressure-sensitive adhesive composition of the present invention is used for optical applications, it is necessary to have transparency, and it is easy to control the strength of adhesive force. Based polymers are preferred.

The acid value is derived from the carboxyl group of the (meth) acrylate copolymer and other acidic groups (such as sulfonic acid group and phosphoric acid group). The acid value means the number of mg of potassium hydroxide required to neutralize free fatty acid and resin acid contained in 1 g of a sample, and the acid value is measured by potentiometric titration.
Specifically, based on JIS-K-2501: 2003, the adhesive is dissolved in a titration solvent in which toluene and methanol (1 + 1) (volume ratio) are mixed, and titrated with a 0.1 mol / L potassium hydroxide / methanol solution. The inflection point of the titration curve is the end point. The acid value is calculated from the titration amount until the end point of the potassium hydroxide / methanol solution.

When the pressure-sensitive adhesive composition of the present invention is applied to a substrate (or a separator) and dried and then polymerized by light irradiation, a pressure-sensitive adhesive tape is obtained.
In the present specification, the pressure-sensitive adhesive tape does not particularly need to be distinguished by width, and includes both pressure-sensitive adhesive tapes and pressure-sensitive adhesive sheets specified in JIS Z 0109. Specific examples thereof include a single-sided adhesive tape (or single-sided adhesive sheet) having an adhesive layer on one side of the substrate, a double-sided adhesive tape (or double-sided adhesive sheet) having an adhesive layer on both sides of the substrate, and a substrate. Transfer tape (transfer tape) in which the pressure-sensitive adhesive layer is formed in a film form without having a film. The pressure-sensitive adhesive sheet can have a large area, and may be used with its wide width, or may be cut into a tape shape and used as a pressure-sensitive adhesive tape. In particular, a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape wound in a roll shape is suitable for an application in which a member is bonded to a display.

FIG. 1A schematically shows an example of a single-sided pressure-sensitive adhesive tape 5 having a pressure-sensitive adhesive layer 2 formed using the pressure-sensitive adhesive composition of the present invention. In this single-sided adhesive tape 5, an adhesive layer 2 is formed on one side of a base material 1 that serves as a support for the adhesive layer 2, and the adhesive surface of the adhesive layer 2 is protected by a separator 3. At the time of use, the separator 3 is peeled to expose the adhesive surface, and the base material 1 is laminated on the back surface of the pressure-sensitive adhesive layer 2 and is bonded to the adherend.
The structure of the double-sided pressure-sensitive adhesive tape having a base material is not particularly shown, but a pressure-sensitive adhesive layer is formed on both surfaces of the base material, and the pressure-sensitive adhesive surface of each pressure-sensitive adhesive layer has a structure protected by a separator.

FIG. 1B schematically shows an example of the transfer tape 6 having the pressure-sensitive adhesive layer 2 formed using the pressure-sensitive adhesive composition of the present invention. In this transfer tape 6, separators 3 and 3 are provided on both sides of the pressure-sensitive adhesive layer 2. At the time of use, one separator 3 is peeled off, and one adhesive surface is exposed and bonded to the adherend. Furthermore, only the film-like pressure-sensitive adhesive layer 2 can be transferred (transferred) to the adherend by peeling off the other separator 3. After the other separator 3 is peeled off, another adherend can be bonded to the new adhesive surface.
About the improvement effect that can prevent the occurrence of white turbidity under environmental conditions at high temperature and high humidity in the present invention, the permeability of moisture such as glass (inorganic glass) or acrylic resin (acrylic glass) to be bonded in the form of transfer tape In particular, a remarkable effect can be obtained in the case of a bad one. This is due to the following reason.
When pasting a resin film with good water molecule permeability, the water molecules dispersed in the adhesive tape layer can be easily penetrated and passed through in the case of a resin film. If the water molecules are reduced, even if water molecules are aggregated, the water molecules are immediately removed through the resin film. However, when pasting a material with poor water molecule permeability, if water molecules aggregate and become cloudy, the water molecules diffuse after spreading to the peripheral edge of the adhesive tape, and thus the cloudiness continues for a long time. Because it will be.

(Pressure-sensitive adhesive composition (Polymer A))
In the present invention, it is preferable that the pressure-sensitive adhesive composition (polymer A) made of an acrylic resin is produced using at least one acrylic monomer having an ester group (—COO—). Examples of the acrylic monomer having an ester group (—COO—) include, for example, a general formula CH ₂ ═CR ¹ —COOR ² (wherein R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 1 to 14 carbon atoms). And (meth) acrylates such as hydroxyl group-containing (meth) acrylates.

Specific examples of the alkyl (meth) acrylate represented by the general formula CH ₂ = CR ¹ -COOR ² (wherein R ¹ represents hydrogen or a methyl group, and R ² represents an alkyl group having 1 to 14 carbon atoms). Are methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate , N-pentyl (meth) acrylate, isopentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate , Decyl (meth) acrylate, Sil (meth) acrylate and the like, it may be used singly or in combination of two or more. Of these, 2-ethylhexyl (meth) acrylate and n-butyl (meth) acrylate are preferably used.
In the alkyl (meth) acrylate, the alkyl group R ² has 1 to 14 carbon atoms from the viewpoint of adhesive strength. It is not preferable that the alkyl group has 15 or more carbon atoms because the adhesive strength may be reduced. The alkyl group R ² preferably has 1 to 12 carbon atoms, preferably 4 to 12 carbon atoms, and more preferably 4 to 8 carbon atoms.
Moreover, among alkyl (meth) acrylates having 1 to 14 carbon atoms in the alkyl group R ² , alkyl (meth) acrylates having 1 to 3 or 13 to 14 carbon atoms in the alkyl group R ² are used as a part of the monomer. However, it is preferable to use an alkyl (meth) acrylate having 4 to 12 carbon atoms of the alkyl group R ² as an essential component (for example, 50 to 100 mol%).
Incidentally, these alkyl groups R ² may be a straight chain or may be branched.

(Monomer B)
Examples of the (meth) acrylate containing a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and polyethylene glycol mono (meth) acrylate. , Polypropylene glycol mono (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, and the like.
Examples of the acrylic monomer containing a carboxyl group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, and 2-acryloylethyl succinic acid.

  The mixing ratio of the acrylic monomer having an ester group and the acrylic monomer having a carboxyl group is such that the pressure-sensitive adhesive is crosslinked to the extent that it can follow the deformation of the adherend to impart heat resistance, and the floating from the adherend and In order to prevent peeling, the mixing ratio of at least one kind of acrylic monomer having an ester group is 85 to 95 parts by weight, and at least one kind of acrylic monomer having a carboxyl group is a mixing ratio of 5 to 15 parts by weight. preferable.

Other monomers can also be added to the raw material monomer for producing the pressure-sensitive adhesive composition (polymer A) made of an acrylic resin. For example, a monomer having a hydrophilic group such as a carboxyl group, an alkoxysilyl group, an amino group, a hydroxyl group, or a sulfonic acid group can be selected and used.
Among the monomers constituting the polymer A, the blending ratio of the alkyl (meth) acrylate and the monomer having a hydrophilic group depends on the characteristics required for the pressure-sensitive adhesive, the type of monomer, the weight ratio of the hydrophilic group in one molecule, and the like. Although different, for example, 5 to 50% by weight is a monomer having a hydrophilic group, and 95 to 50% by weight is preferably an alkyl (meth) acrylate.

Examples of the acrylic monomer containing an alkoxysilyl group include γ-trimethoxysilylpropyl (meth) acrylate, γ-methyldimethoxysilylpropyl (meth) acrylate, and γ-triethoxysilylpropyl (meth) acrylate. Can be mentioned.
Examples of the non-acrylic monomer containing an alkoxysilyl group include vinylmethoxysilane and vinyltrimethoxysilane.
Examples of the acrylic monomer containing an amino group include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, and monomethylaminoethyl (meth) acrylate. In addition to (meth) acrylates containing amino groups, (meth) acrylic acid amide, itaconic acid amide, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylamide, N-methoxymethylacrylamide, N-ethoxymethyl ( Examples include meth) acrylamide, N-methoxymethyl (meth) acrylamide, and N-butoxymethyl (meth) acrylamide.

The polymer A is preferably composed of an acrylic monomer (an alkyl (meth) acrylate and an acrylic monomer having a hydrophilic group) for the most part (for example, 50% by weight or more, more preferably 80% by weight or more) Monomers other than acrylic monomers (non-acrylic monomers) can be used in combination so as not to impair the effects of the present invention.
Polymerization of the acrylic monomer constituting the polymer A and the optionally blended non-acrylic monomer can be carried out by a known method such as solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, etc. The easy solution polymerization is preferably used. Specific examples of the organic solvent used in the solution polymerization reaction include aromatic hydrocarbons such as toluene and xylene, aliphatic esters such as ethyl acetate and butyl acetate, and alicyclic hydrocarbons such as cyclohexane. , Aliphatic hydrocarbons such as hexane, pentane and the like, but not particularly limited as long as the polymerization reaction is not inhibited. These solvents may be used alone or in combination of two or more. What is necessary is just to determine the usage-amount of a solvent suitably.
In general, in the solution polymerization reaction, the molecular weight of the polymer produced decreases as the polymerization temperature increases. In carrying out the polymerization reaction at the reflux temperature of the solvent, the polymer A can be obtained while removing the heat of the polymerization reaction by using a solvent having a boiling point temperature suitable for the polymerization reaction.
Moreover, the pressure sensitive adhesive composition (polymer A) comprising the acrylic resin of the present invention is used as an adhesive composition for an adhesive tape to be bonded to the ITO surface of a transparent conductive laminate having a transparent conductive film formed thereon. Even if it is used, the change in the resistance value of the transparent conductive film can be suppressed, and a so-called acid-free pressure-sensitive adhesive composition is preferable.
In this case, the acid value of the polymer A is more preferably 0 to 33 as an index that can suppress the change in the resistance value of the transparent conductive film.
For the polymer A which is a pressure-sensitive pressure-sensitive adhesive composition comprising the acrylic resin of the present invention, a commercially available pressure-sensitive pressure-sensitive adhesive may be used. As such a commercially available pressure-sensitive adhesive, a so-called acid-free adhesive composition such as an acrylic adhesive having no carboxyl group and acrylic acid can be used. As a commercially available acid-free pressure-sensitive adhesive composition, for example, SK Dyne 2147 (Soken Chemical Co., Ltd.), and as a commercially available adhesive tape with little change in ITO resistance value, for example, CS9621 (Nitto Denko Corporation), MHM-F25 , MHM-F50, MHM-F125 (Nichiei Kako Co., Ltd.), ZB7032W (DIC Corporation) and the like.

The molecular weight distribution of the polymer A is preferably 70,000 or more in terms of number average molecular weight (Mn) and 1,000,000 or more in terms of weight average molecular weight (Mw). Furthermore, the weight average molecular weight (Mw) is more preferably 12 million or more. Thus, when the molecular weight of the polymer A is large, the heat resistance and the weather resistance are more excellent.
If the molecular weight is too large, the viscosity is too high and the processability is deteriorated. It is considered that this upper limit can be further widened by devising the coating method such as raising the temperature of the paint. However, when coating is performed at room temperature, for example, a material having an Mw of less than 5 million is considered preferable.

The pressure-sensitive adhesive composition of the present invention contains at least one monomer of a hydroxyl group-containing (meth) acrylate (monomer B).
In one preferable embodiment of the raw material composition for pressure-sensitive adhesives of the present invention, an acrylic polymer obtained by polymerizing a monomer of alkyl (meth) acrylate and acrylic acid not containing a hydroxyl group, and a hydroxyl group-containing ( The monomer of (meth) acrylate exists in the state of being mixed separately without being copolymerized. In another preferred embodiment, the polymer A obtained by polymerizing a monomer containing a hydrophilic monomer and a hydroxyl group-containing (meth) acrylate monomer are contained in the pressure-sensitive adhesive raw material composition. .

The content of monomer B (the total amount when monomer B is two or more) is preferably 5 to 20 parts by weight with respect to 100 parts by weight of the main polymer (polymer A), and the temperature is 85 ° C. X 5-15 parts by weight is more preferable when high durability is required such as in a test under a humidity of 85% RH.
The pressure-sensitive adhesive composition comprising a known hydroxyl group-containing acrylic polymer may contain some (meth) acrylate monomers containing hydroxyl groups as unreacted monomers. Compared to the content of hydroxyl group-containing (meth) acrylate in the raw material composition for pressure-sensitive adhesives of the invention, the content is only extremely low.

The pressure-sensitive adhesive composition (polymer C) of the present invention is a pressure-sensitive pressure-sensitive adhesive composition (polymer A) made of an acrylic resin, and at least one hydroxyl group-containing (meth) acrylate monomer (monomer B), After preparing a pressure-sensitive adhesive raw material mixture obtained by mixing a photopolymerization initiator, the pressure-sensitive adhesive raw material mixture can be used to carry out a polymerization reaction by light irradiation.
A state of acrylic syrup containing a pressure-sensitive adhesive composition (polymer A) comprising an acrylic resin, a hydroxyl group-containing (meth) acrylate monomer (monomer B), and a photopolymerization initiator, or coating and hydroxyl In order to uniformly disperse the group-containing monomer (monomer B), the acrylic syrup is prepared as a resin solution dissolved in an organic solvent.

In the step of dissolving the hydroxyl group-containing (meth) acrylate monomer (monomer B) in the pressure-sensitive adhesive composition (polymer A) comprising the acrylic resin to obtain an acrylic syrup, the monomer B is converted to the polymer A Before being dissolved, it is preferably washed with an organic solvent or the like as necessary. Thereby, the unreacted acrylic monomer can be removed from the polymer A. Moreover, the weight of the polymer A can be quantified more accurately, and an acrylic syrup in which the contents of the monomer B and the photopolymerization initiator used in the next step are more appropriately adjusted can be produced. When preparing an acrylic syrup, after the monomer B is dissolved in the polymer A, washing may be performed with the above organic solvent or the like.
In addition, after adding a photopolymerization initiator to an acrylic syrup, the polymerization reaction may proceed if ultraviolet light contained in room light or sunlight acts on the acrylic syrup, making it difficult to manage. Is preferably added immediately before the coating step, which is a subsequent step. This is the same for resin solutions in which acrylic syrup is dissolved in an organic solvent. Care should be taken to prevent the photoinitiator from starting the reaction before coating and film formation due to some external factor. It is.

  The pressure-sensitive adhesive composition (polymer C) of the present invention is preferably a pressure-sensitive adhesive coating liquid containing an appropriate amount of an organic solvent in order to impart fluidity suitable for application to a substrate. Specific examples of the organic solvent used in the adhesive coating solution include aromatic hydrocarbons such as toluene and xylene, aliphatic esters such as ethyl acetate and butyl acetate, and alicyclic carbonization such as cyclohexane. Examples thereof include aliphatic hydrocarbons such as hydrogen, hexane, and pentane, but are not particularly limited as long as the purpose of coating and dispersion can be achieved.

  When preparing the pressure-sensitive adhesive coating solution, it is only necessary to obtain an organic solvent solution in which the polymer A, the monomer B, and the photopolymerization initiator are dissolved in an organic solvent at an appropriate blending ratio, and the order of dissolution is particularly limited. Not. For example, the monomer B and the photopolymerization initiator may be directly added to the acrylic syrup in which the polymer A is dissolved, or the liquid obtained by dissolving the monomer B and the photopolymerization initiator in an appropriate amount of an organic solvent may be added to the polymer A. good.

In the present invention, the hydroxyl group-containing (meth) acrylate monomer used as the monomer B is 2-hydroxylethyl (meth) acrylate, 2-hydroxylpropyl (meth) acrylate, 3-hydroxylpropyl (meth) acrylate, 4 -Hydroxylbutyl (meth) acrylate, 5-hydroxylpentyl (meth) acrylate, 6-hydroxylhexyl (meth) acrylate, 7-hydroxylheptyl (meth) acrylate, 8-hydroxyloctyl (meth) acrylate, 7-methyl-8- Hydroxyl octyl (meth) acrylate, 2-methyl-8-hydroxyl octyl (meth) acrylate, 9-hydroxyl nonyl (meth) acrylate, 10-hydroxyl decyl (meth) acrylate, 2-hydroxyethyl lauryl (meth) acrylate and the like, it may be may be used alone in combination of two or more. In particular, 2-hydroxylethyl (meth) acrylate, hydroxylpropyl (meth) acrylate, and 4-hydroxylbutyl (meth) acrylate are preferably used.
The hydroxyl group-containing (meth) acrylate is obtained by esterifying one hydroxyl group of two hydroxyl groups of a dihydric alcohol (diol compound) with acrylic acid or methacrylic acid. A hydroxyalkyl (meth) acrylate having one vinyl group at a time is preferably used.

  The type of monomer B used in the present invention varies depending on the pressure-sensitive adhesive strength and storage elastic modulus of the pressure-sensitive adhesive tape, but when a pressure-sensitive adhesive tape having rework properties is used, a hard pressure-sensitive adhesive composition having a high storage elastic modulus ( Polymer C) may be used, so that an approximate guide for monomer B is preferably one having a Tg of room temperature or higher. When strong adhesive force is required or when it is desired to lower the storage elastic modulus, conversely, a monomer B having a Tg lower than room temperature, preferably a Tg minus temperature is required.

(Photopolymerization initiator)
The photopolymerization initiator (polymerization catalyst) used in the present invention is not particularly limited. For example, acetophenone photopolymerization initiator, benzoin photopolymerization initiator, benzophenone photopolymerization initiator, thioxanthone photopolymerization start Agents, thioxanthone photopolymerization initiators, and the like.
As the acetophenone photopolymerization initiator, acetophenone, p- (tert-butyl) 1 ′, 1 ′, 1′-trichloroacetophenone, chloroacetophenone, 2 ′, 2′-diethoxyacetophenone, hydroxylacetophenone, 2,2- Examples include dimethoxy-2′-phenylacetophenone, 2-aminoacetophenone, dialkylaminoacetophenone and the like.
Benzoin photopolymerization initiators include benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 1-hydroxyl cyclohexyl phenyl ketone, 2-hydroxyl 2-methyl-1-phenyl-2-methyl Propan-1-one, 1- (4-isopropylphenyl) -2-hydroxyl 2-methylpropan-1-one, benzyldimethyl ketal and the like can be mentioned.
Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, methyl-o-benzoylbenzoate, 4-phenylbenzophenone, hydroxylbenzophenone, hydroxylpropylbenzophenone, acrylic benzophenone, 4,4′-bis (dimethyl). Amino) benzophenone and the like.
Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, diethylthioxanthone, and dimethylthioxanthone.
Other photopolymerization initiators include α-acyl oxime ester, benzyl- (o-ethoxycarbonyl) -α-monooxime, acyl phosphine oxide, glyoxy ester, 3-ketocoumarin, 2-ethylanthraquinone, camphorquinone, tetra Examples include methyl thiuram sulfide, azobisisobutyronitrile, benzoyl peroxide, dialkyl peroxide, tert-butyl peroxypivalate and the like.

These photopolymerization initiators may be used alone or in combination of two or more. Content of a photoinitiator is 0.005-5 mass% in the weight percentage which makes 100 mass% the whole quantity of polymeric compound (In the case of this invention, (meth) acrylate containing a hydroxyl group). Is preferable, and it is especially preferable that it is 0.01-2 mass%. If the content of the photopolymerization initiator is 0.005% by mass or more, the polymerizable compound can be polymerized in a short time, and if it is 5% by mass or less, the residue of the photopolymerization initiator hardly remains in the cured product. .
Further, as described above, the hydroxyl group-containing (meth) acrylate monomer B (total amount when two or more types are used) is preferably 3 to 20 parts by weight with respect to 100 parts by weight of the polymer A. For example, when high durability at high temperature and high humidity is required, for example, when a test is performed in an environment of temperature 85 ° C. × humidity 85% RH, it is more preferably 5 to 15 parts by weight. The content of the photopolymerization initiator based on parts by weight is preferably 0.01 to 0.5 parts by weight.

  In the present invention, in the pressure-sensitive adhesive composition after photopolymerization, it is desirable to polymerize the monomer in the range of 40 to 80% by weight, preferably 50 to 75% by weight. That is, it is desirable to leave unreacted monomer in the range of 60 to 20% by weight, preferably 50 to 25% by weight. When the polymerization rate is less than 40% by weight, sufficient tackiness is not imparted to the obtained polymer, and when the polymerization rate exceeds 80% by weight, the cohesive force is reduced, and the pressure-sensitive adhesive When the layer is peeled and removed, an adhesive residue phenomenon may occur.

Here, the material of the base material used when the pressure sensitive adhesive raw material composition is applied to form the pressure sensitive adhesive tape has transparency and heat resistance, and inhibits the curing of the ultraviolet curable resin composition. Those having small scattering and absorption in the ultraviolet region near 350 nm to 400 nm are preferable. For example, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polysulfone, polyethersulfone, polystyrene, polyacrylate, polyetheretherketone, polycarbonate, polyolefin such as polyethylene and polypropylene, polyamide, nylon, polyimide , Fluorine such as triacetyl cellulose (cellulose triacetate), cellulose diacetate, poly (meth) acrylic acid alkyl ester, poly (meth) acrylic acid ester copolymer, polymethyl methacrylate, polytetrafluoroethylene and polytrifluoroethylene Resin, polyvinyl chloride, polyvinylidene chloride copolymer, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol, cellophane, cellulose film, etc. It can be mentioned. These materials may be used alone or in combination of two or more.
In particular, among the substrates, it is preferable to use polyethylene terephthalate from the viewpoints of heat resistance, ultraviolet light transmittance, and cost.
In addition, it is preferable that the thickness of a base material has 16 micrometers-200 micrometers, and it is still more preferable that it has 50 micrometers-188 micrometers. If the thickness of the substrate is too thin, the handling properties are poor, and if the thickness of the substrate is too thick, it is disadvantageous in terms of cost and handling properties.

(Transparent resin film)
As the base material 1 used for the pressure-sensitive adhesive tape of the present invention, a transparent resin film is preferable. Since this transparent resin film is assumed to be subjected to a high-temperature heat treatment of about 150 ° C. in the process of processing into an element or device using a transparent conductive laminate protected by sticking an adhesive tape, It is required to have heat resistance that can withstand at least 150 ° C.
As a material of such a heat resistant resin film, any one selected from a resin film group consisting of polyethylene terephthalate (PET), polyethylene terephthalate (PEN), and cyclic polyolefin (COP) which are heat resistant resins. It is preferable that These heat-resistant resins all have a heat-resistant temperature of 200 ° C. or higher, and can be used without any problems at 150 ° C., which is a normal heat treatment temperature of the transparent conductive laminate.
Moreover, since the transparent resin film used for the adhesive tape of this invention can be wound up in roll shape from the point of workability | operativity in the manufacturing process of a transparent conductive laminated body, it has flexibility. is required. For this reason, it is preferable that the thickness of a transparent resin film is 500 micrometers or less, and a more preferable thickness is 10-150 micrometers. If the thickness is 10 μm or less, the flexibility is too strong and difficult to handle, and if the thickness exceeds 500 μm, the rigidity is too strong to be wound into a roll, which is not preferable.

In addition, the thermal shrinkage rate of the transparent resin film used for the pressure-sensitive adhesive tape of the present invention at 150 ° C. for 30 minutes is any of MD direction (flow direction during film molding) and TD direction (width direction during film molding). Also in the direction, 0.5% or less is preferable.
The thermal contraction rate of the transparent resin film used in the adhesive tape of the present invention is 0.5% or less in both the MD direction and the TD direction as described above, thereby causing thermal strain generated in the heat treatment process. It may be possible to reduce the curl due to.
For this reason, the transparent resin film used for the pressure-sensitive adhesive tape of the present invention is preferably subjected to an annealing treatment for reducing the heat shrinkage rate. By performing the annealing treatment, a polyester resin having a heat shrinkage rate of 1% or less, preferably 0.5% or less can be used. The transparent resin film used in the present invention can be annealed by a conventionally known method.

As the transparent resin film used for the pressure-sensitive adhesive tape of the present invention, for example, a biaxially oriented polyethylene terephthalate (PET) film is preferable because of its excellent mechanical strength. The biaxially oriented PET film is generally obtained by subjecting an unstretched PET film to a crystal orientation by being stretched about 2 to 6 times in the longitudinal direction and the width direction, respectively, and then heat-treated. Furthermore, when a biaxially oriented PET film is used, the heat shrinkage ratio of the PET film dimension after heating the PET film at 150 ° C. for 30 minutes is less than 0.5% in both the longitudinal direction and the direction perpendicular thereto. What is adjusted by annealing treatment or the like is more preferable. Such a PET film is easy to manufacture a high-definition panel because the PET film substrate is not easily deformed in the process of heat treatment at a high temperature.
Further, the transparent resin film used for the adhesive tape of the present invention is an unstretched transparent PET film formed by a melt extrusion film forming method or a solution casting film forming method, and further subjected to an annealing treatment and heated. The shrinkage rate can be 0.5% or less.
In addition, it is preferable to manufacture by the solution casting film forming method because the force applied to the film in the MD direction and the TD direction of the film can be reduced.

  Moreover, cyclic polyolefin is also used as a transparent resin film used for the adhesive tape of this invention. The cyclic polyolefin is a polyolefin having an alicyclic structure in the main chain. Examples of the alicyclic structure of the main chain include a cycloalkane structure and a cycloalkene structure. Specific examples of the cyclic polyolefin include a norbornene polymer, a monocyclic olefin polymer, a cyclic conjugated diene polymer and a hydrogenated product thereof, a vinyl alicyclic hydrocarbon polymer and a hydrogenated product thereof, and a cyclic olefin. Preferred examples include addition monomers of ethylene monomers and ethylene. Examples of the commercially available cyclic polyolefin-based resin include trade name: ZEONOR 1060R manufactured by Nippon Zeon Co., Ltd.

(Peeling film)
In the pressure-sensitive adhesive tape of the present invention, a release film 3 subjected to a release treatment is laminated via a pressure-sensitive adhesive layer 2 on one surface (for example, the upper surface of FIG. 1) of the transparent resin film. As the substrate of the release film used in the present invention, paper such as fine paper, glassine paper, coated paper, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polyphenylene sulfide (PPS), Examples thereof include polyolefin resins such as polyethylene and polypropylene, synthetic resins such as polyvinyl chloride resins, polyurethane resins, acrylic resins, and fluorine resins. Synthetic resins are preferably used because of easy handling.
The thickness of the base material of the release film is not particularly limited, and a foamed base material can be used, and a multi-layer structure in which a plurality of sheet-like base materials are laminated can also be used. Furthermore, the sheet-like substrate may be colored, or a coat layer may be laminated for imparting functionality.
A release treatment is performed on one side of the substrate of the release film used in the present invention. As a peeling treatment method, a known method such as applying a silicone compound, a fluorine-based compound, a long-chain alkyl-based compound or the like to one side of a sheet-like substrate can be used.

(Transparent conductive laminate)
The pressure-sensitive adhesive tape of the present invention is a transparent conductive laminate in which a transparent conductive film layer is formed on one surface of a transparent substrate and a hard coat layer is preferably formed on the other surface, or transparent on both surfaces of the transparent substrate. The transparent conductive laminate in which the conductive film layer is formed is used by being attached to the transparent conductive film. The transparent substrate used for the transparent conductive laminate is selected from the group of heat resistant resins consisting of polyethylene terephthalate (PET) resin, polyethylene terephthalate (PEN) resin, and cyclic polyolefin (COP) resin. A seed or a transparent glass plate is preferred.
When the transparent substrate is a transparent resin substrate, the thickness of the transparent substrate used for the transparent conductive laminate is preferably 10 to 250 μm, and more preferably 30 to 200 μm. If the thickness of the transparent resin base material is less than 10 μm, it is not preferable because it becomes difficult to handle. If the thickness of the transparent resin substrate is larger than 250 μm, the transparency is lowered, the cost is increased, and the processability in the production process of the transparent conductive laminate is deteriorated, which is not preferable. From the above points, the thickness of the transparent resin substrate is preferably 10 to 250 μm, and more preferably 30 to 200 μm. In addition, for the purpose of improving the adhesion between the transparent resin base material and the transparent conductive film, an appropriate easily adhesive resin layer is laminated on the surface of the transparent resin base material, flame treatment, corona treatment, plasma treatment. You may give surface treatments, such as. Moreover, you may provide a base layer between a transparent resin base material and a transparent conductive film.

The hard coat layer formed on the transparent base material of the transparent conductive laminate needs only to have a hard coat property that can be used for the surface material of the touch panel, and is practical if the measured value in the pencil hardness test is usually 2H or more. No problem. The resin used for the hard coat layer is not particularly limited, and silicone-based and melamine-based thermosetting hard coat resins, silicone-based, acrylic-based ultraviolet curable hard coat resins, and the like can be used.
Moreover, 1-10 micrometers is preferable and, as for the thickness of a hard-coat layer, 2-8 micrometers is more preferable. If the thickness of the hard coat layer is less than 1 μm, the hard coat property cannot be obtained and the scratch resistance is lowered, and when an ultraviolet curable hard coat resin is used, poor curing tends to occur.
Also, if the thickness of the hard coat layer is greater than 10 μm, it is not preferable because cracks are likely to occur in the hard coat layer and the hard coat film itself is likely to curl. You may add the additive for providing various functions, such as an agent, as needed. As a method for forming the hard coat layer on the surface of the transparent substrate, a conventionally known method such as a reverse coating method, a die coating method, or a gravure coating method can be used.

Moreover, any one selected from the group of methods for forming a transparent conductive film comprising a sputtering method, a vacuum deposition method, and an ion plating method is provided on one surface of the transparent substrate of the transparent conductive laminate according to the present invention. The transparent conductive film layer is formed by one method.
Preferably, the transparent conductive film forming step or after the transparent conductive film forming step includes a step of forming a wiring pattern made of the transparent conductive film. As a method for forming the wiring pattern of the transparent electrode, a known method can be used. A typical method includes patterning by photolithography. In addition, a glass substrate having a conductive film layer formed for the time being can be used as a transparent conductive substrate.

The coating apparatus for applying the adhesive raw material composition to the substrate may be any apparatus as long as it has a means for uniformly supplying and applying the adhesive raw material composition on the base material. A device comprising a tank for storing an adhesive raw material composition, a liquid feed pump, piping, a foreign matter removal filter, and a coater head so that the adhesive raw material composition can be supplied and coated on the substrate. Preferred (not shown). The coater head is preferably a die coater, for example.
A thin film layer (coating film) of the pressure-sensitive adhesive raw material composition is formed on one side of the substrate by the coating apparatus. The pressure-sensitive adhesive raw material composition immediately after coating with a coating apparatus is uncured and liquid, and has fluidity suitable for coating.

When the raw material composition for adhesives is a syrup type, it is preferable that the thickness of a coating film is between 0.05-3 mm, More preferably, it is 0.1-2 mm. The thickness of the coating film is approximately equal to the thickness of the pressure-sensitive adhesive layer obtained by photopolymerization. Therefore, the thickness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape of the present invention is preferably between 0.05 and 3 mm, more preferably 0.1 to 2 mm.
When the raw material composition for the pressure-sensitive adhesive is a solution type, the thickness of the coating film before drying is thicker than that of the syrup type, and is a number obtained by dividing the thickness of the coating film by the concentration. The thickness of the coating film after drying is the same as that of the syrup type.
If the coating film is too thin, the thickness of the pressure-sensitive adhesive layer is also reduced, so that the impact absorbing performance is deteriorated. Moreover, when the coating film is too thick, it is disadvantageous in that the cost increases.

  In FIG. 2, an example of the manufacturing method of the adhesive tape of this invention is shown typically. In the apparatus shown in FIG. 2, the pressure-sensitive adhesive raw material composition is supplied from the die coater 21 onto the substrate 11 to form the coating film 12. Reference numeral 22 denotes a backup roll 22 that is disposed to face the die coater 21 and supports the substrate 11. The base material 11 on which the coating film 12 is formed is transported along the longitudinal direction thereof, and dried in the drying chamber 23 so as to remove the solvent in the coating film 12. On the dried coating film 12, the separator 13 is supplied from the separator supply means 24 onto the coating film 12 and bonded by a nip roll 25.

The temperature in the drying chamber 23 may be a temperature at which the solvent in the coating film 12 is sufficiently volatilized, and is desirably maintained at a temperature at which the polymerizable compound is not thermally polymerized.
The separator supply means 24 includes a roll body around which the separator 13 is wound, a shaft that holds the roll body, and the like.
The nip roll 25 is composed of a pair of rolls that sandwich the base material 11 on which the coating film 12 is formed and the separator 13, and is an apparatus that bonds the two together. It is preferable to provide a pressurizing means for pasting, and at least one of the rolls is preferably made of rubber so that a uniform pressure can be easily applied to the film.

  Examples of the separator include polycarbonate film, polyarylate film, polyethersulfone film, polysulfone film, polyester film, polyamide film, polyimide film, polystyrene film, polyolefin film, norbornene film, phenoxy ether type polymer film, and organic permeation resistance A release film having a release property with a silicone release agent or the like applied to a single-layer or multilayer plastic film such as a gas-resistant film and having a release property at least on one side; Release film that has release properties; Films that have release properties such as fluororesin films and certain polyolefin-based films; And the like. The thickness of the separator is not limited, but is usually 5 to 500 μm, preferably 10 to 100 μm in many cases. The separator is selected according to the pressure-sensitive adhesive used and the intended use (peel strength).

The ultraviolet irradiation device 26 includes a light source unit that generates ultraviolet light and a cooling device that removes heat generated by the light source. The light source part is free of lamp light sources such as high-pressure mercury lamps and metal halide lamps, and light-emitting diodes having a light emission peak in the ultraviolet region, as long as they can obtain an ultraviolet irradiation amount that sufficiently cures the polymerizable compound in the coating film 12. Can be selected.
The coating film 12 polymerizes the polymerizable compound in the coating film 12 by appropriate light irradiation, thereby increasing the cohesive force and expressing adhesiveness.

Moreover, when manufacturing the double-sided adhesive tape without a support like a transfer tape as an adhesive tape of this invention, a separator is supplied not only as the separator 13 but as the base material 11 for conveyance, and an adhesive. A layer is formed on the separator.
Moreover, when producing a double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of the support as the pressure-sensitive adhesive tape of the present invention, the coating liquid is applied and dried and the coating film is photopolymerized simultaneously or sequentially on each side. Can be done.

  After light irradiation for the photopolymerization reaction, curing for the crosslinking reaction is performed. Although the curing method is not particularly limited, for example, the adhesive tape wound up on a roll is left under a predetermined temperature and time condition. The curing temperature depends on the type of the crosslinking agent and the like, but is preferably heated (for example, 40 to 80 ° C.) as necessary.

The obtained pressure-sensitive adhesive layer has an adhesive force to glass and acrylic resin when the pressure-sensitive adhesive surface is bonded to an adherend and left in an environment of 23 ° C. and 50% RH for 1 hour and then peeled at a peeling speed of 300 mm / min. Is preferably 10 N / 25 mm or more. In order to obtain such a high adhesive strength, the storage elastic modulus (G ′) at 23 ° C. and 1 Hz of the adhesive constituting the adhesive layer is 1 × 10 ⁴ Pa or more and less than 1 × 10 ⁶ Pa. In the case where high durability is required such as in a test under an environment of 85 ° C. and 85% RH, it is more preferably 5 × 10 ⁴ Pa or more and 5 × 10 ⁵ Pa or less. When the storage elastic modulus is low, the pressure-sensitive adhesive layer is soft and easily deformed, so that it is easy to bond. When the storage elastic modulus is within the above range, the two members (for example, a hard material such as a glass plate or an acrylic plate) are pasted together, the durability after pasting, the adhesive strength, etc. It becomes.

  The pressure-sensitive adhesive tape of the present invention can be suitably used for applications in which a member is bonded to the ITO surface of a transparent conductive laminate used for a touch panel or the like.

Hereinafter, the present invention will be specifically described with reference to examples.
Using the pressure-sensitive adhesive material composition shown in Table 1 below, pressure-sensitive adhesive tapes of Examples 1 to 3 and Comparative Examples 1 to 6 were produced by the following production method.

  In Table 1, 2094 and 2147 represent SK Dyne (registered trademark) 2094 and SK Dyne (registered trademark) 2147, respectively, and “AA / 2EHA” represents a copolymer of acrylic acid and 2-ethylhexyl acrylate. , “4HBA” represents 4-hydroxylbutyl acrylate, and Irg184 and Irg651 represent Irgacure (registered trademark) 184 and Irgacure (registered trademark) 651, respectively. Here, the photopolymerization initiator of the product name: Irgacure (registered trademark) 184 contains 1-hydroxy-cyclohexyl-phenyl-ketone as an active ingredient, and the photopolymerization initiator of the product name: Irgacure (registered trademark) 651 is started. The agent contains benzyl dimethyl ketal as an active ingredient.

Example 1
As a material of the pressure-sensitive adhesive composition (Polymer A), SK Dyne 2094 (Soken Chemical Co., Ltd., acid value: 33) and E-AX (Soken Chemical Co., Ltd.) as a curing agent were each 1000 g: 2. A pressure-sensitive adhesive composition (polymer A) comprising an acrylic resin polymer was obtained using a solution prepared by blending with 7 g.
The resulting pressure-sensitive adhesive composition (Polymer A) was further added with 4-hydroxylbutyl acrylate (Osaka Organic Materials Co., Ltd .; 4HBA) as a hydroxyl group-containing (meth) acrylate monomer (Monomer B). 0.0 g and an alkylphenone-based photopolymerization initiator (manufactured by Ciba Japan Co., Ltd .; product name: Irgacure 184) were added to prepare 0.10 g of an adhesive material mixture.
Using the applicator on the upper surface of a base film made of polyethylene terephthalate (Mitsubishi Resin Co., Ltd .; product name: T100, thickness 38 μm), the thickness of the pressure-sensitive adhesive layer after drying is 200 μm. After being applied as described above, it was dried to produce a laminate in which an adhesive layer was laminated.
Next, a separator (manufactured by Mitsubishi Plastics Co., Ltd .; product name; MRF, thickness 38 μm) was bonded to the upper surface of the pressure-sensitive adhesive layer of the obtained laminate to produce a laminated film in which the pressure-sensitive adhesive was laminated.
After that, while transporting the obtained laminated film, the laminated film of the pressure-sensitive adhesive as the base material is transported by a continuous UV irradiation apparatus using a high-pressure mercury lamp so that the irradiation amount is about 200 mJ (wavelength 300 nm to 400 nm). The UV irradiation was carried out while adjusting the speed, the amount of UV irradiation, etc., the polymerization reaction was carried out using a photopolymerization initiator, and finally the pressure-sensitive adhesive composition (polymer C) was laminated. An adhesive tape was obtained.

(Example 2)
As a material of the pressure-sensitive adhesive composition (Polymer A), SK Dyne 2147 (Soken Chemical Co., Ltd., acid value: 0), TD-75 (Soken Chemical Co., Ltd.) as a curing agent, and A-50 (Additive as an additive) A pressure-sensitive adhesive composition (Polymer A) made of an acrylic resin polymer was obtained using solutions prepared by mixing 1000 g: 0.4 g: 0.6 g respectively. The obtained pressure-sensitive adhesive composition (Polymer A) was further mixed with 50 hydroxyl group-containing (meth) acrylate monomer (Monomer B) as 4-hydroxylbutyl acrylate (Osaka Organic Materials Co., Ltd .; 4HBA). 0.0 g and an alkylphenone-based photopolymerization initiator (manufactured by Ciba Japan Co., Ltd .; product name: Irgacure 184) were added to prepare 0.10 g of the pressure-sensitive adhesive mixture, and the same as in Example 1. Thus, an adhesive tape of Example 2 was obtained.

(Example 3)
As a material of the pressure-sensitive adhesive composition (Polymer A), SK Dyne 2147 (Soken Chemical Co., Ltd., acid value: 0), TD-75 (Soken Chemical Co., Ltd.) as a curing agent, and A-50 (Additive as an additive) A pressure-sensitive adhesive composition (Polymer A) made of an acrylic resin polymer was obtained using solutions prepared by mixing 1000 g: 0.4 g: 0.6 g respectively. The resulting pressure-sensitive adhesive composition (Polymer A) was further added with 4-hydroxylbutyl acrylate (Osaka Organic Materials Co., Ltd .; 4HBA) as a hydroxyl group-containing (meth) acrylate monomer (Monomer B). 0.0 g and an alkylphenone-based photopolymerization initiator (manufactured by Ciba Japan Co., Ltd .; product name: Irgacure 184) were added to prepare 0.10 g of the pressure-sensitive adhesive mixture, and the same as in Example 1. Thus, an adhesive tape of Example 3 was obtained.

(Comparative Example 1)
As a reference (blank) for comparison with the change in surface resistivity of the ITO surface when the adhesive tape of the present invention is bonded to the ITO surface, an ITO film (Nakai Kogyo Co., Ltd .: Metaforce 125R2 × A, surface resistance) The ITO film as it was was put into an oven without bonding the adhesive tape of the present invention to a value of 250Ω / m ² ).

(Comparative Example 2)
SK Dyne 2094 (Soken Chemical Co., Ltd., acid value: 33) as a material for the pressure-sensitive adhesive composition (Polymer C) and E-AX (Soken Chemical Co., Ltd.) as a curing agent are blended at 1000 g: 2.7 g, respectively. Then, a pressure-sensitive adhesive tape of Comparative Example 2 was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition (Polymer C) was prepared.

(Comparative Example 3)
As a material for the pressure-sensitive adhesive composition (Polymer C), SK Dyne 2147 (Soken Chemical Co., Ltd., acid value: 0), TD-75 (Soken Chemical Co., Ltd.) as a curing agent, and A-50 (Soken) as an additive. Chemical Co., Ltd.) was mixed at 1000 g: 0.4 g: 0.6 g, respectively, and a pressure-sensitive adhesive tape of Comparative Example 3 was obtained in the same manner as in Example 1 except that a pressure-sensitive adhesive composition (Polymer C) was prepared. It was.

(Comparative Example 4)
As a material of the pressure-sensitive adhesive composition (Polymer A), SK Dyne 2147 (Soken Chemical Co., Ltd., acid value: 0), TD-75 (Soken Chemical Co., Ltd.) as a curing agent, and A-50 (Additive as an additive) A pressure-sensitive adhesive composition (Polymer A) made of an acrylic resin polymer was obtained using solutions prepared by mixing 1000 g: 0.4 g: 0.6 g respectively. The obtained pressure-sensitive adhesive composition (Polymer A) was further subjected to 150 4-hydroxylbutyl acrylate (Osaka Organic Materials Co., Ltd .; 4HBA) as a hydroxyl group-containing (meth) acrylate monomer (Monomer B). 0.0 g and an alkylphenone-based photopolymerization initiator (manufactured by Ciba Japan Co., Ltd .; product name: Irgacure 184) were added to the mixture to prepare a pressure-sensitive adhesive mixture (polymer C). In the same manner as in Example 1, the adhesive tape of Comparative Example 4 was obtained.

(Comparative Example 5)
As a material of the pressure-sensitive adhesive composition (Polymer A), a polymer obtained by making acrylic acid / 2-ethylhexyl acrylate = 87: 13 (acid value: 101.25) with ethyl acetate to 40% concentration, and EX as a curing agent -830 (Nagase ChemteX Corporation) was used to prepare a pressure-sensitive adhesive composition (Polymer A) made of an acrylic resin polymer, using a solution prepared by blending each with 1000 g: 8.0 g. The obtained pressure-sensitive adhesive composition (Polymer A) was further added with 60-hydroxylbutyl acrylate (Osaka Organic Materials Co., Ltd .; 4HBA) as a hydroxyl group-containing (meth) acrylate monomer (Monomer B). 0.04 g and alkylphenone photopolymerization initiator (Ciba Japan Co., Ltd .; product name: Irgacure 651) was added to 0.40 g, and this was carried out except that a raw material mixture for pressure-sensitive adhesive (Polymer C) was prepared. In the same manner as in Example 1, a pressure-sensitive adhesive tape of Comparative Example 5 was obtained.

(Comparative Example 6)
As a material of the pressure-sensitive adhesive composition (Polymer A), a polymer obtained by making acrylic acid / 2-ethylhexyl acrylate = 95: 5 (acid value: 38.2) into ethyl acetate at a concentration of 34%, and a curing agent EX -830 (Nagase ChemteX Corporation) was used to prepare a pressure-sensitive adhesive composition (polymer A) composed of an acrylic resin polymer, using a solution prepared by blending each 1000 g: 6.0 g. The obtained pressure-sensitive adhesive composition (Polymer A) was further subjected to 40-hydroxylbutyl acrylate (Osaka Organic Materials Co., Ltd .; 4HBA) as a hydroxyl group-containing (meth) acrylate monomer (Monomer B). 0.06 g and 0.66 g of an alkylphenone photopolymerization initiator (manufactured by Ciba Japan Co., Ltd .; product name: Irgacure 651) were added to prepare a pressure-sensitive adhesive mixture (polymer C). In the same manner as in Example 1, the adhesive tape of Comparative Example 6 was obtained.

<Testing method for adhesive tape>
Using the adhesive tapes of Examples 1 to 3 and Comparative Examples 2, 3, 5, and 6 above, a test sample piece in which an adhesive tape was bonded to an ITO film was prepared, and the resistance value change magnification of the ITO film was measured. And a cloudiness confirmation test was conducted. Moreover, as a blank, in Comparative Example 1, the ITO film as it was without attaching an adhesive tape to the ITO film was put into an oven, and the resistance value change magnification of the ITO film was measured.

(Measurement method of resistance value change magnification of transparent conductive film)
An ITO film (manufactured by Nakai Kogyo Co., Ltd., product name: Metaforce 125R2 × A, surface resistance value 250 Ω / m ² ) was prepared, and was cut into strips having a size of 25 mm wide × 120 mm long. Adhesive tape with a width of 25mm x length of 100mm from the center position is bonded to the ITO surface of the cut strip-shaped ITO film piece via the adhesive layer, and the adhesive tape is attached to the ITO film. Laminated test sample pieces were prepared. In order to improve the adhesive strength of the pressure-sensitive adhesive tape bonded to the ITO surface of the test sample piece, the test sample piece was put into an autoclave and subjected to a heating operation at a pressure of 0.5 MPa × temperature of 40 ° C. for 15 minutes.
Silver paste (manufactured by Fujikura Kasei Co., Ltd., product name: Dotite, model number: FA-301CA) is applied to the part of the test sample piece where the adhesive tape on both ends of the ITO film is not bonded to form a measurement terminal. Then, after carrying out thermal baking at a temperature of 80 ° C. for 1 hour, the resistance value between both ends of the ITO film was measured by applying a tester to the measurement terminals at both ends of the test sample piece to obtain the initial resistance value of the transparent conductive film.
Thereafter, the test sample piece is put into an oven having a temperature of 85 ° C. and a humidity of 85% RH, taken out after 500 hours, and again a resistance value between both ends of the ITO film by applying testers to the measurement terminals at both ends of the ITO film. Was measured as a resistance value after an environmental test at high temperature and high humidity.
The resistance value change magnification of the ITO film of the test sample piece was calculated by the following formula.
(Resistance change ratio of transparent conductive film) = (resistance value after environmental test at high temperature and high humidity) / (initial resistance value)

(White turbidity confirmation test)
A test sample piece prepared by measuring the resistance value change magnification of the transparent conductive film was put in an environment of high temperature and high humidity of temperature 85 ° C. × humidity 85% RH, and taken out after 12 hours. Thereafter, the sample was left in an environment of temperature 23 ° C. × humidity 50% RH, and the appearance change of the test sample piece was visually confirmed. A cloudy product was evaluated as (x), and a sample in which cloudiness was not confirmed was evaluated as (◯).

<Test results>
The results of the above test are shown in Table 2.

(Measurement result of resistance value change magnification of transparent conductive film)
From the test results shown in Table 2, compared to Comparative Examples 2 and 3 using only a pressure-sensitive adhesive composition (polymer A) made of an acrylic resin having a commercially available acid value of 0 to 33, To the pressure-sensitive adhesive composition (polymer A) comprising an acrylic resin having the same commercially available acid value of 0 to 33, at least one monomer (monomer B) containing a hydroxyl group-containing (meth) acrylate, In Examples 1 to 3, which are pressure-sensitive adhesive compositions (Polymer C) produced by adding a photopolymerization initiator and performing photopolymerization, the resistance value change magnification of the ITO film is kept low.
At least one of the hydroxyl group-containing (meth) acrylate monomers (monomer B) does not increase the resistance value change rate of the ITO film, but rather has a commercially available acid value of 0 to 33. When added to a pressure-sensitive adhesive composition (polymer A) made of an acrylic resin, polymer A is diluted with monomer B and the hydroxyl groups in the resin increase, thereby increasing the resistance value change magnification of the ITO film. We think that there is effect to keep low. In Comparative Examples 5 and 6 having an acid value larger than those of Examples 1 to 3, the resistance value change magnification of the ITO film was remarkably increased even though the monomer B and the photopolymerization initiator were introduced. From this, it can be confirmed that not only the presence of the polymerized monomer B but also the acid value of the pressure-sensitive adhesive composition (polymer A) is important for the effect of suppressing the resistance value change rate of the ITO film to be lower. It was.

(Result of cloudiness confirmation test of adhesive tape)
About Examples 1-3 and Comparative Examples 5 and 6, cloudiness was not able to be confirmed. In Comparative Examples 2 and 3, cloudiness was confirmed. In Comparative Examples 2 and 3, since the monomer B and the photopolymerization initiator are not introduced, the monomer B is not polymerized even when UV irradiation is performed. In Comparative Example 2, since it was not a pressure-sensitive adhesive having an effect of improving cloudiness, it was confirmed that polymerizing monomer B was effective in improving cloudiness. Further, in Comparative Example 4, since monomer B and a photopolymerization initiator are present, the photoinitiator reacts by performing UV irradiation. However, in Comparative Example 4, the content of monomer B is compared with Example 3. Therefore, in Comparative Example 4, it became cloudy. From this, it was confirmed that not only the presence of the polymerized monomer B but also the composition ratio is important for the white turbidity prevention effect when the white turbidity is taken out under high temperature and high humidity under normal conditions.
Moreover, the graph which shows the change of the haze value after taking out from the oven for environmental tests in high temperature, high humidity of FIG. 3 does not produce cloudiness after the environmental test in high temperature, high humidity as an effect of this invention for reference. It is shown. Example 1 relating to the pressure-sensitive adhesive tape of the present invention was excellent in that the haze value did not change at all immediately after taking out from the oven for environmental testing at high temperature and high humidity and even after 60 minutes passed from the oven. It turns out that it has white turbidity prevention performance.
On the other hand, in Comparative Example 2, the haze value rose to about 11% as a maximum value within a few minutes immediately after taking out from the environmental test oven at high temperature and high humidity, and then the haze value gradually increased as the standing time passed. Although it shows a tendency to decrease, it can be seen that the cloudy state continues for 120 minutes or more.
This evaluation is a change that occurs when separators or resin films such as polyethylene terephthalate (PET) are used. However, the timing of cloudiness is the same for samples such as glasses with poor gas permeability or acrylic plates and glasses. However, it can take several days for the cloudiness to disappear. Any white turbidity generated in an environmental test at high temperature and high humidity disappeared and became transparent when left at room temperature for several hours.

  From the above results, the pressure-sensitive adhesive polymer (polymer A) comprising an acrylic resin having an acid value of 0 to 33, which is the main component of the pressure-sensitive adhesive composition of the present invention, and the hydroxyl group-containing (meth) acrylate By obtaining a pressure-sensitive adhesive composition (polymer C) by subjecting a raw material mixture for pressure-sensitive adhesive obtained by mixing at least one kind of monomer (monomer B) and a photopolymerization initiator to a polymerization reaction by light irradiation, A method for producing a pressure-sensitive adhesive composition for a pressure-sensitive adhesive tape that suppresses a change in the resistance value of a transparent conductive film even after being bonded to an ITO surface, and does not cause white turbidity in a pressure-sensitive adhesive layer after an environmental test at high temperature and high humidity, An adhesive composition and an adhesive tape using the same can be provided.

DESCRIPTION OF SYMBOLS 1 ... Base material, 2 ... Adhesive layer, 3 ... Separator, 5 ... Single-sided adhesive tape, 6 ... Transfer tape, 11 ... Substrate or separator to be conveyed, 12 ... Coating film, 13 ... Separator, 21 ... Die coater, 22 ... backup roll, 23 ... drying chamber, 24 ... separator supply means, 25 ... nip roll, 26 ... ultraviolet irradiation device.

Claims (6)

It is a manufacturing method of the adhesive composition of the adhesive tape bonded on the ITO surface of the transparent conductive film made of ITO, and the physical properties (K) through at least the following steps (1) to (2) A pressure-sensitive adhesive composition (Polymer C).
(1) A pressure-sensitive adhesive composition (polymer A) made of an acrylic resin having an acid value of 0 to 33, at least one monomer (monomer B) of a hydroxyl group-containing (meth) acrylate, and photopolymerization A step of preparing a raw material mixture for an adhesive obtained by mixing an initiator.
(2) The process of obtaining the adhesive composition (polymer C) which has a physical property (K) by making the polymerization reaction by light irradiation using the said raw material mixture for adhesives.
Physical Properties (K): After applying a pressure-sensitive adhesive composition (Polymer C) on the ITO surface to form a thin film having a thickness of 200 μm after drying, 500 hours of execution was performed in an environment of temperature 85 ° C. × humidity 85% RH. After taking out from the oven for high-temperature and high-humidity environmental testing, the resistance value change magnification of the ITO film is 1.7 times or less compared to the initial value, and the pressure-sensitive adhesive composition (polymer C) layer immediately after taking out from the oven There is no cloudiness. It is a manufacturing method of the adhesive composition of the adhesive tape bonded on the ITO surface of the transparent conductive film made of ITO, and the physical properties (K) are obtained through at least the following steps (1) to (3). A pressure-sensitive adhesive composition (Polymer C).
(1) A pressure-sensitive adhesive composition (polymer A) made of an acrylic resin having an acid value of 0 to 33, at least one monomer (monomer B) of a hydroxyl group-containing (meth) acrylate, and photopolymerization A step of preparing a raw material mixture for an adhesive obtained by mixing an initiator.
(2) The process of apply | coating the said raw material mixture for adhesives to the base film consisting of a long thermoplastic resin so that it may become thickness 20-500 micrometers after drying, and obtaining a long coating film.
(3) A step of obtaining a pressure-sensitive adhesive composition (polymer C) having physical properties (K) on the base film by performing a polymerization reaction by light irradiation using the long coating film.
Physical Properties (K): After applying a pressure-sensitive adhesive composition (Polymer C) on the ITO surface to form a thin film having a thickness of 200 μm after drying, 500 hours of execution was performed in an environment of temperature 85 ° C. × humidity 85% RH. After taking out from the oven for high-temperature and high-humidity environmental testing, the resistance value change magnification of the ITO film is 1.7 times or less compared to the initial value, and the pressure-sensitive adhesive composition (polymer C) layer immediately after taking out from the oven There is no cloudiness. Pressure-sensitive adhesive composition (polymer A) comprising an acrylic resin having an acid value of 0 to 33: 100 parts by weight of a solid content;
At least one monomer (monomer B) of hydroxyl group-containing (meth) acrylate: 5 to 15 parts by weight;
Photopolymerization initiator: 0.01 to 0.5 parts by weight;
A pressure-sensitive adhesive composition (Polymer C) characterized by having a physical property (K).
Physical Properties (K): After applying a pressure-sensitive adhesive composition (Polymer C) on the ITO surface to form a thin film having a thickness of 200 μm after drying, 500 hours of execution was performed in an environment of temperature 85 ° C. × humidity 85% RH. After taking out from the oven for high-temperature and high-humidity environmental testing, the resistance value change magnification of the ITO film is 1.7 times or less compared to the initial value, and the pressure-sensitive adhesive composition (polymer C) layer immediately after taking out from the oven There is no cloudiness.   A pressure-sensitive adhesive tape, wherein a pressure-sensitive adhesive composition (polymer C) produced by the method according to claim 1 or 2 is laminated on a base film.   A pressure-sensitive adhesive tape, wherein the pressure-sensitive adhesive composition (polymer C) according to claim 3 is laminated on a base film.   The pressure-sensitive adhesive tape according to claim 4 or 5, wherein the pressure-sensitive adhesive tape is used for bonding a member to a display.

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