JP5961201B2 - Adhesive composition, adhesive sheet, laminate for touch panel, and capacitive touch panel - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet (particularly a pressure-sensitive adhesive sheet for a touch panel), a laminate for a touch panel, and a capacitive touch panel.

In recent years, the rate of mounting touch panels on mobile phones, portable game devices, and the like has increased, and for example, capacitive touch panels capable of detecting multiple points (hereinafter simply referred to as touch panels) are attracting attention.
Usually, when manufacturing a touch panel, a pressure-sensitive adhesive composition or an adhesive composition is used in order to bring the members such as a display device and a touch panel sensor into close contact with each other. These compositions are often used after being formed into a sheet.

  For example, Patent Document 1 discloses an adhesive composition for a touch panel containing a (meth) acrylate monomer and Lucirin TPO (monoacylphosphine oxide) (Examples).

JP2013-144749A

  On the other hand, the pressure-sensitive adhesive sheet obtained from the pressure-sensitive adhesive composition is required to have various characteristics when used for a touch panel. For example, excellent adhesion is required from the viewpoint of durability of the touch panel. In addition, from the viewpoint of environmental adaptability of the touch panel, it is required that malfunction does not easily occur in various use environments such as a cold region and a warm region. That is, a low malfunction occurrence rate is required.

  Under these circumstances, when the present inventors formed a pressure-sensitive adhesive sheet using a pressure-sensitive adhesive composition containing a radical polymerizable monomer and a monoacylphosphine oxide with reference to Patent Document 1, the adhesiveness is recently required. It became clear that it did not meet the level. Moreover, when the said adhesive sheet was used for the touch panel, it became clear that the malfunction occurrence rate does not necessarily satisfy the level required recently.

  Therefore, in view of the above circumstances, the present invention is excellent in adhesiveness when used as an adhesive sheet, and when used in a capacitive touch panel as an adhesive sheet, under a wide temperature environment from low temperature to high temperature. It aims at providing the adhesive composition which can suppress generation | occurrence | production of a malfunctioning.

As a result of intensive studies on the above problems, the present inventors have used bisacylphosphine oxide in combination with monoacylphosphine oxide, and used a specific monomer as a radical polymerizable monomer, and are included in the pressure-sensitive adhesive composition. The inventors have found that the above problem can be solved by specifying the ratio between the number of moles of oxygen atoms and the number of moles of carbon atoms, and have reached the present invention.
That is, the present inventors have found that the above problem can be solved by the following configuration.

(1) A pressure-sensitive adhesive containing monoacylphosphine oxide (A1), bisacylphosphine oxide (A2), and a radical polymerizable monomer (B) having a solubility parameter (SP value) of 8.0 to 10.0 A composition comprising:
The radical polymerizable monomer (B) is at least one selected from the group consisting of a branched alkyl group and an alicyclic hydrocarbon group (excluding an alicyclic hydrocarbon group having an unsaturated hydrocarbon group). Having the group
The content of the monoacylphosphine oxide (A1) with respect to the total amount of the pressure-sensitive adhesive composition is 1.5% by mass or more,
Mass ratio (b / a) of the content (b) of the radical polymerizable monomer (B) and the total content (a) of the monoacylphosphine oxide (A1) and the bisacylphosphine oxide (A2) Is 3.0 to 30.0,
The pressure-sensitive adhesive composition, wherein the ratio of the number of moles of oxygen atoms and the number of moles of carbon atoms (number of moles of oxygen atoms / number of moles of carbon atoms) contained in the pressure-sensitive adhesive composition is 0.1 or less.
(2) The pressure-sensitive adhesive composition according to (1), further comprising at least one photopolymerization initiator selected from the group consisting of an aminoketone photopolymerization initiator and a hydroxyketone photopolymerization initiator.
(3) Furthermore, the adhesive composition as described in said (1) or (2) containing the sensitizing dye represented by general formula (I) mentioned later.
(4) The pressure-sensitive adhesive composition according to any one of (1) to (3), further comprising at least one polymerization inhibition inhibitor selected from the group consisting of phosphites, amines, and thiols. .
(5) The adhesive sheet obtained from the adhesive composition in any one of said (1)-(4).
(6) The pressure-sensitive adhesive sheet according to (5), wherein the thickness is 50 μm or more.
(7) The pressure-sensitive adhesive sheet according to the above (5) or (6), which is a pressure-sensitive adhesive sheet for a touch panel.
(8) A laminate for a touch panel comprising the pressure-sensitive adhesive sheet according to (7) and a capacitive touch panel sensor.
(9) Further, a protective substrate is provided,
The laminated body for touchscreens as described in said (8) provided with the said protective substrate, the said adhesive sheet, and the said capacitive touch panel sensor in this order.
(10) A capacitive touch panel comprising the capacitive touch panel sensor, the adhesive sheet according to (7), and a display device in this order.

  As shown below, according to the present invention, when used as a pressure-sensitive adhesive sheet, it has excellent adhesion, and when used as a pressure-sensitive adhesive sheet in a capacitive touch panel, under a wide temperature environment from low temperature to high temperature. A pressure-sensitive adhesive composition that can suppress the occurrence of malfunction can be provided.

It is sectional drawing of the one aspect | mode of the laminated body for touchscreens of this invention. It is sectional drawing of another aspect of the laminated body for touchscreens of this invention. It is sectional drawing of the electrostatic capacitance type touch panel of this invention. It is a top view of one embodiment of a capacitive touch panel sensor. It is sectional drawing cut | disconnected along the cutting line AA shown in FIG. It is an enlarged plan view of a 1st detection electrode. It is a partial cross section of other embodiment of an electrostatic capacitance type touch panel sensor. It is a partial cross section of other embodiment of an electrostatic capacitance type touch panel sensor. It is a partial top view of one Embodiment of other embodiment of an electrostatic capacitance type touch panel sensor. It is sectional drawing cut | disconnected along the cutting line AA shown in FIG.

Below, the adhesive composition of this invention, the adhesive sheet using the adhesive composition of this invention, the laminated body for touch panels, and a capacitive touch panel are demonstrated.
In this specification, (meth) acrylate represents acrylate or methacrylate, and (meth) acryloyl group represents acryloyl group or methacryloyl group.
Furthermore, the numerical range expressed using “to” in the present specification means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Adhesive composition]
The pressure-sensitive adhesive composition of the present invention (hereinafter also referred to as the composition of the present invention) has a monoacylphosphine oxide (A1), a bisacylphosphine oxide (A2), and a solubility parameter (SP value) of 8.0-10. 0.0. A pressure-sensitive adhesive composition containing a radically polymerizable monomer (B) which is 0.0.
Here, the radical polymerizable monomer (B) is selected from the group consisting of a branched alkyl group and an alicyclic hydrocarbon group (excluding an alicyclic hydrocarbon group having an unsaturated hydrocarbon group). Have at least one group. Moreover, content of the said monoacyl phosphine oxide (A1) with respect to the whole quantity of the said adhesive composition is 1.5 mass% or more. Further, the mass ratio (b / b) of the content (b) of the radical polymerizable monomer (B) and the total content (a) of the monoacylphosphine oxide (A1) and the bisacylphosphine oxide (A2). a) is 3.0-30.0. The ratio of the number of moles of oxygen atoms and the number of moles of carbon atoms (number of moles of oxygen atoms / number of moles of carbon atoms) contained in the pressure-sensitive adhesive composition is 0.1 or less.
Since the composition of this invention takes such a structure, it is thought that a desired effect is acquired.

The reason is not clear, but it is presumed that it is as follows.
The monoacylphosphine oxide (A1) and bisacylphosphine oxide (A2) contained in the composition of the present invention function as a photopolymerization initiator. Therefore, when the composition of the present invention is irradiated with light, the radical polymerizable monomer (B) contained in the composition of the present invention is polymerized to form an adhesive sheet. Here, the composition of the present invention uses, in addition to the monoacylphosphine oxide (A1) as described above, the bisacylphosphine oxide (A2) excellent in light deep permeability. Therefore, when the composition of the present invention is irradiated with light, it is considered that the polymerization reaction proceeds uniformly over the entire system and the adhesion is improved.
Here, the monoacylphosphine oxide (A1) contained in the composition of the present invention functions as a photopolymerization initiator and assists the solubility of the bisacylphosphine oxide (A2). Moreover, since the radically polymerizable monomer (B) contained in the composition of the present invention has a specific SP value and a specific group, the compatibility with the bisacylphosphine oxide (A2) is extremely high. As a result, it is considered that the above effect by the bisacylphosphine oxide (A2) is secured.
As for these things, as the comparative example mentioned later shows, when only (i) monoacylphosphine oxide (A1) is used (comparative examples 1-5 and 7), adhesiveness becomes inadequate. ii) When only bisacylphosphine oxide (A2) is used (Comparative Example 8), a homogeneous composition capable of forming an adhesive sheet cannot be obtained, and (iii) a specific radical polymerizable monomer When (B) is not used (Comparative Examples 11 to 13 and 15), it is speculated that the adhesion becomes insufficient.
In the composition of the present invention, the ratio of the number of moles of oxygen atoms and the number of moles of carbon atoms (number of moles of oxygen atoms / number of moles of carbon atoms) contained in the composition is not more than a specific value. The resulting adhesive sheet has a small change in relative permittivity depending on the usage environment, and when used in a capacitive touch panel, it is thought that it can suppress the occurrence of malfunctions in a wide range of temperature environments from low to high temperatures. It is done.

  Hereinafter, each component contained in the composition of this invention is explained in full detail.

<Monoacylphosphine oxide (A1)>
The monoacylphosphine oxide (A1) contained in the composition of the present invention is not particularly limited, and a known monoacylphosphine oxide can be used. The composition of the present invention may contain two or more monoacylphosphine oxides.
As a suitable aspect of monoacylphosphine oxide (A1), the monoacylphosphine oxide represented by a following formula (A1) is mentioned, for example.

In the above formula (A1), R ^A11 represents a hydrocarbon group which may have a substituent. Although it does not restrict | limit especially as a hydrocarbon group, As an example, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, etc. are mentioned, Especially, it is preferable that it is an aromatic hydrocarbon group.
The aliphatic hydrocarbon group may be linear, branched or cyclic. Specific examples of the aliphatic hydrocarbon group include a linear or branched alkyl group (particularly having 1 to 20 carbon atoms), a linear or branched alkenyl group (particularly having 2 to 20 carbon atoms), Examples thereof include a linear or branched alkynyl group (particularly, having 2 to 20 carbon atoms). The aliphatic hydrocarbon group is preferably a linear or branched alkyl group.
Examples of the aromatic hydrocarbon group include an aryl group and a naphthyl group. As said aryl group, C6-C18 aryl groups, such as a phenyl group, a tolyl group, a xylyl group, etc. are mentioned, for example.
The substituent that the hydrocarbon group may have is not particularly limited, but specific examples include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.) and the like. Can be mentioned. Specific examples and preferred embodiments of the aliphatic hydrocarbon group and the aromatic hydrocarbon group are as described above. The substituent is preferably an aliphatic hydrocarbon group.

In the formula (A1), R ^A12 and R ^A13 each independently represent a hydrocarbon group or a hydrocarbon oxy group (—OR: where R represents a hydrocarbon group) which may have a substituent. . Specific examples of the hydrocarbon group of the hydrocarbon group which may have a substituent and the hydrocarbon group (R) of the hydrocarbon oxy group are the same as the hydrocarbon group described above. Moreover, the specific example and suitable aspect of a substituent which a hydrocarbon group or a hydrocarbon oxy group may have are the same as the substituent mentioned above.
One of R ^A12 and R ^A13 is preferably an aromatic hydrocarbon group which may have a substituent. When one of R ^A12 and R ^{A13 is} an aromatic hydrocarbon group which may have a substituent, the other may have a phenyl group (particularly having 6 to 18 carbon atoms) or an alkoxy group (which may have a substituent) Particularly preferred are those having 1 to 5 carbon atoms, and more preferred are phenyl groups (particularly 6 to 18 carbon atoms) which may have a substituent.

  Specific examples of the monoacylphosphine oxide (A1) include benzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyl-diphenylphosphine oxide, 3, Examples include 4-dimethylbenzoyl-diphenylphosphine oxide and 2,4,6-trimethylbenzoyl-phenylethoxyphosphine oxide.

  The absorbance at 400 nm of a 0.1% by mass acetonitrile solution of monoacylphosphine oxide (A1) is preferably 1.5 or less, and more preferably 1.3 or less. The lower limit of the absorbance of the monoacylphosphine oxide (A1) is not particularly limited, but is preferably 0.2 or more, and more preferably 0.3 or more.

Content of the monoacylphosphine oxide (A1) with respect to the whole quantity of the composition of this invention is 1.5 mass% or more. Especially, it is preferable that it is 1.5-3.9 mass%. In the present specification, when the composition of the present invention contains a solvent, the total amount of the composition of the present invention refers to the total amount of components other than the solvent.
When the content of the monoacylphosphine oxide (A1) with respect to the total amount of the composition of the present invention is less than 1.5% by mass, the curability by light is lowered and the adhesiveness of the obtained pressure-sensitive adhesive sheet becomes insufficient.

<Bisacylphosphine oxide (A2)>
The bisacylphosphine oxide (A2) contained in the composition of the present invention is not particularly limited, and a known bisacylphosphine oxide can be used. The composition of the present invention may contain two or more bisacylphosphine oxides.
As a suitable aspect of bisacylphosphine oxide (A2), the bisacylphosphine oxide represented by a following formula (A2) is mentioned, for example.

In the formula (A2), R ^{A21 to} R ^A23 each independently represent a hydrocarbon group that may have a substituent. Specific examples and preferred embodiments of the hydrocarbon group and the substituent are the same as those of R ^A11 described above.

  Specific examples of bisacylphosphine oxide (A2) include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide. Bis (2,6-dimethylbenzoyl) -ethylphosphine oxide and the like.

  The absorbance at 430 nm of a 0.1% by mass acetonitrile solution of bisacylphosphine oxide (A2) is preferably 0.1 or more, and more preferably 0.2 or more. The upper limit of the absorbance of the bisacylphosphine oxide (A2) is not particularly limited, but is preferably 0.8 or less, and more preferably 0.4 or less.

  Although content in particular of bisacylphosphine oxide (A2) with respect to the whole quantity of the composition of this invention is not restrict | limited, It is preferable that it is 0.1-2.5 mass%.

  The mass ratio (a2 / a1) between the content (a2) of the bisacylphosphine oxide (A2) and the content (a1) of the monoacylphosphine oxide (A1) is not particularly limited, but the adhesion of the resulting pressure-sensitive adhesive sheet In addition, from the reason that the step following ability is more excellent, it is preferably 0.30 or more, and more preferably 0.40 or more.

<Radically polymerizable monomer (B)>
The composition of the present invention has an “aliphatic group having a solubility parameter (SP value) of 8.0 to 10.0 and a branched alkyl group and an alicyclic hydrocarbon group (provided that the unsaturated hydrocarbon group has an alicyclic ring). A radically polymerizable monomer (B) having at least one group selected from the group consisting of: (excluding the formula hydrocarbon group). The composition of the present invention may contain two or more radically polymerizable monomers (B).

  The radical polymerizable monomer (B) has a radical polymerizable group. Although it does not restrict | limit especially as a radically polymerizable group, For example, (meth) acryloyl group, itaconic ester group, crotonic ester group, isocrotonic ester group, maleic ester group, styryl group, vinyl group, acrylamide group, methacrylamide Group and the like. Of these, a (meth) acryloyl group, a vinyl group, a styryl group, an acrylamide group, and a methacrylamide group are preferable, and a (meth) acryloyl group and a styryl group are more preferable.

Further, as described above, the radical polymerizable monomer (B) is selected from the group consisting of a branched alkyl group and an alicyclic hydrocarbon group (excluding an alicyclic hydrocarbon group having an unsaturated hydrocarbon group). Having at least one group.
Although it does not restrict | limit especially as a branched alkyl group, A C3-C30 thing is preferable and a thing of 5-20 is more preferable. Specific examples of the branched alkyl group include an iso-propyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, and a 2-ethylhexylalkyl group.
Although it does not restrict | limit especially as an alicyclic hydrocarbon group, A C3-C30 thing is preferable and a thing of 5-20 is more preferable. The alicyclic hydrocarbon group may be monocyclic or polycyclic. Specific examples of the monocyclic type include a cyclopentyl group and a cyclohexyl group. Specific examples of the polycyclic type include an isobornyl group and an adamantyl group. The alicyclic hydrocarbon group does not have an unsaturated hydrocarbon group. When the alicyclic hydrocarbon group has an unsaturated hydrocarbon group, the compatibility with the above-described bisacylphosphine oxide (A2) is lowered, and preparation becomes difficult. Examples of the alicyclic hydrocarbon group having an unsaturated hydrocarbon group include a dicyclopentenyl group.

As described above, the SP value of the radical polymerizable monomer (B) is 8.0 to 10.0. Here, the SP value is Michael M.M. Collman, John F. Graf, Paul C.M. Painter (Pensylvania State Univ.), "Specific Interactions and the Miscibility of Polymer Blends" (1991), Technological Publishing Co. Inc. It is a value obtained by the calculation described in. However, since -COOH group and -OH group are not described, R.I. F. Values described in Polymer Engineering and Science by Fedors, 14 (2), 147 (1974) are used. When the SP value is out of the range of 8.0 to 10.0, the compatibility with the above-described bisacylphosphine oxide (A2) is lowered, and the preparation becomes difficult. In this specification, the unit of SP value is (J / cm ³ ) ^1/2 .

  As a suitable aspect of a radically polymerizable monomer (B), a solubility parameter (SP value) is 8.0-10.0 and the compound represented by a following formula (B1) is mentioned, for example.

In the above formula (B1), R ^B11 represents a hydrogen atom or an alkyl group (preferably a methyl group).

In the above formula (B1), L ^B1 represents a single bond or a divalent organic group. Although it does not restrict | limit especially as a bivalent organic group, For example, a bivalent aliphatic hydrocarbon group (for example, alkylene group, Preferably it is C1-C8), A bivalent aromatic hydrocarbon group (for example, arylene group) Preferably having 6 to 12 carbon atoms), —O—, —S—, —SO ₂ —, —N (R) — (R: alkyl group), —CO—, —NH—, —COO—, —CONH. -Or a combination thereof (for example, an alkyleneoxy group, an alkyleneoxycarbonyl group, an alkylenecarbonyloxy group, and the like). Among these, an alkylene group, —O—, or a combination thereof is preferable.

In the above formula (B1), R ^B12 represents a branched alkyl group or an alicyclic hydrocarbon group (excluding an alicyclic hydrocarbon group having an unsaturated hydrocarbon group). Specific examples and preferred embodiments of the branched alkyl group and the alicyclic hydrocarbon group (excluding the alicyclic hydrocarbon group having an unsaturated hydrocarbon group) are as described above.

  Specific examples of the radical polymerizable monomer (B) include 2-ethylhexyl methacrylate (SP value: 8.1), cyclohexyl acrylate (SP value: 8.3), isobornyl acrylate (SP value: 8.33), And isobornyl methacrylate (SP value: 8.3).

  Although content in particular of the radically polymerizable monomer (B) with respect to whole quantity of the composition of this invention is not restrict | limited, It is preferable that it is 1-50 mass%, and it is more preferable that it is 5-30 mass%.

The mass ratio (b / a) between the content (b) of the radical polymerizable monomer (B) and the total content (a) of the monoacylphosphine oxide (A1) and the bisacylphosphine oxide (A2) is 3.0 to 30.0. The mass ratio (b / a) is preferably 4.0 or more, and more preferably 6.0 or more, from the reason that the adhesiveness and the step following ability of the obtained pressure-sensitive adhesive sheet are more excellent.
If the mass ratio (b / a) is out of the range of 3.0 to 30.0, a homogeneous composition capable of forming a pressure-sensitive adhesive sheet cannot be obtained, or a homogeneous composition can be obtained. Adhesion is insufficient.

<Optional component>
The composition of the present invention may contain components (arbitrary components) other than the above-described components as long as the effects and the purpose are not impaired.
Examples of the optional component include radical polymerizable monomers other than the above-described radical polymerizable monomer (B), photopolymerization initiators other than the above-described monoacylphosphine oxide (A1) and the above-mentioned bisacylphosphine oxide (A2), and sensitization. Examples thereof include a dye, a polymerization inhibition inhibitor, a resin component, and a solvent.

(Radical polymerizable monomer (M) other than radical polymerizable monomer (B))
The radical polymerizable monomer (M) is not particularly limited as long as it is a radical polymerizable monomer other than the radical polymerizable monomer (B). For example, among compounds having a radical polymerizable group, the SP value is 8.0 to 10. Among compounds having a radical polymerizable group that are out of the range of 0, having a branched alkyl group and an alicyclic hydrocarbon group (excluding an alicyclic hydrocarbon group having an unsaturated hydrocarbon group) There are no such things. Specific examples of the radical polymerizable group are the same as those of the above-described radical polymerizable monomer (B).

  Specific examples of the radical polymerizable monomer (M) include methyl (meth) acrylate, 2-hydroxylethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and 2-ethylhexyl acrylate (SP value: 7.8). Etc.

  The content of the radically polymerizable monomer (M) with respect to the total amount of the composition of the present invention is not particularly limited, but is preferably 1 to 20% by mass.

(Photopolymerization initiator (P) other than monoacylphosphine oxide (A1) and bisacylphosphine oxide (A2))
The photopolymerization initiator (P) is not particularly limited as long as it is a photopolymerization initiator other than monoacylphosphine oxide (A1) and bisacylphosphine oxide (A2).
Examples of such a photopolymerization initiator include aminoketone photopolymerization initiators such as 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (Irgacure 369, manufactured by BASF); Hydroxy ketone photopolymerization initiators such as cyclohexyl phenyl ketone (Irgacure 184) and hydroxy-2-methyl-1-phenyl-propan-1-one (Darocur 1173); benzophenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone Benzophenone photopolymerization initiators such as; benzyl methyl ketal (Esacure KB1, manufactured by Nippon Sebel Hegner); 2-hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer (Esacu eKIP150, manufactured by Nippon Siebel Heguna Co., Ltd.) and the like.
The composition of the present invention preferably contains at least one photopolymerization initiator selected from the group consisting of aminoketone photopolymerization initiators and hydroxyketone photopolymerization initiators.

  Although content of the photoinitiator (P) with respect to the whole quantity of the composition of this invention is not restrict | limited, It is preferable that it is 0.1-5 mass%.

(Sensitizing dye)
The sensitizing dye is not particularly limited, and examples thereof include thioxanthones, thiochromanones, carbazoles, and xanthones. The composition of the present invention may contain two or more sensitizing dyes.

  As a suitable aspect of a sensitizing dye, the sensitizing dye represented by the following general formula (I) is mentioned, for example.

In the general formula (I), R _{11 to} R ₁₈ are each independently a hydrogen atom, alkyl group, halogen atom, hydroxy group, cyano group, nitro group, amino group, alkylthio group, alkylamino group, alkoxy group, Represents an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxyl group or a sulfo group; R ₁₅ or R ₁₆ and R ₁₇ or R ₁₈ may be condensed with each other to form a 5- to 6-membered aliphatic ring, aromatic ring, or heterocyclic ring.
R _{11 to} R ₁₄ are preferably each independently a hydrogen atom or a halogen atom. R _{15 to} R ₁₈ are preferably each independently a hydrogen atom or an alkyl group.

  The composition of the present invention preferably contains a sensitizing dye represented by the above general formula (I).

  The content of the sensitizing dye with respect to the total amount of the composition of the present invention is not particularly limited, but is preferably 0.1 to 2% by mass.

(Polymerization inhibitor)
The polymerization inhibition inhibitor has a function of suppressing polymerization inhibition by oxygen. Polymerization inhibition suppression is not particularly limited, and examples thereof include phosphites (eg, triphenyl phosphite), amines (eg, aniline, hindered amines, DBU (diazabicycloundecene)), thiols (eg, dodecane). Thiol, pentaerythritol tetra (3-mercaptopropionate) and the like. The composition of the present invention may contain two or more polymerization inhibition inhibitors.
The composition of the present invention preferably contains at least one polymerization inhibition inhibitor selected from the group consisting of phosphites, amines and thiols.

  The content of the polymerization inhibition inhibitor relative to the total amount of the composition of the present invention is not particularly limited, but is preferably 0.1 to 1.0% by mass.

(Resin component)
The composition of the present invention preferably contains a resin component. The resin component is not particularly limited, but diene rubber (for example, liquid rubber such as liquid polybutadiene), petroleum resin (for example, aromatic petroleum resin, aliphatic petroleum resin, resin by C9 fraction, etc.), terpene Resin (for example, hydrogenated terpene resin, aromatic modified terpene resin), rosin resin (for example, partially hydrogenated gum rosin resin, erythritol modified wood rosin resin, tall oil rosin resin, wood rosin resin), coumarone indene resin (for example, And a tackifier such as polystyrene, a copolymer of styrene and α-methylstyrene, and the like. Of these, liquid rubber and terpene resin are preferable.
When the composition of the present invention contains a terpene resin, the content of the terpene resin relative to the total amount of the composition of the present invention is not particularly limited, but is preferably 10 to 50% by mass.
When the composition of the present invention contains a liquid rubber, the content of the liquid rubber with respect to the total amount of the composition of the present invention is not particularly limited, but is preferably 10 to 50% by mass.

(solvent)
The composition of the present invention may contain a solvent, if necessary. Examples of the solvent used include water, organic solvents (for example, alcohols such as methanol, ketones such as acetone, amides such as formamide, sulfoxides such as dimethyl sulfoxide, esters such as ethyl acetate, ethers, and the like. Etc.), or a mixed solvent thereof.

  In addition to the above, the composition of the present invention is filled with a surface lubricant, leveling agent, antioxidant, corrosion inhibitor, light stabilizer, ultraviolet absorber, polymerization inhibitor, silane coupling agent, inorganic or organic filling. Depending on the use for which various conventionally known additives such as powders such as agents, metal powders and pigments, particles and foils are used, they can be added as appropriate.

<Ratio of the number of moles of oxygen atoms and the number of moles of carbon atoms contained in the pressure-sensitive adhesive composition>
The ratio of the number of moles of oxygen atoms to the number of moles of carbon atoms in the composition of the present invention (number of moles of oxygen atoms / number of moles of carbon atoms) (hereinafter also referred to as “O / C ratio”) is 0.1. It is as follows. Especially, it is preferable that it is 0.005-0.05.
When the O / C ratio exceeds 0.1, a malfunction is likely to occur when the adhesive sheet is used for a capacitive touch panel.
In addition, when the composition of this invention contains a solvent, O / C ratio points out O / C ratio in all the components other than a solvent.

The O / C ratio can be determined by calculating the number of moles of oxygen atoms and the number of moles of carbon atoms for each component in the pressure-sensitive adhesive composition.
For example, when the pressure-sensitive adhesive composition contains monoacylphosphine oxide (A1), bisacylphosphine oxide (A2), radical polymerizable monomer (B), terpene resin, and liquid rubber, the O / C ratio is [ Number of moles of oxygen atom of monoacylphosphine oxide (A1) + number of moles of oxygen atom of bisacylphosphine oxide (A2) + number of moles of oxygen atom of radical polymerizable monomer (B) + number of moles of oxygen atom of terpene resin + Number of moles of oxygen atom of liquid rubber] / [number of moles of carbon atom of monoacylphosphine oxide (A1) + number of moles of carbon atom of bisacylphosphine oxide (A2) + carbon atom of radical polymerizable monomer (B) The number of moles of carbon atoms in the liquid rubber of the terpene resin].

<Method for preparing pressure-sensitive adhesive composition>
The preparation method in particular of the composition of this invention is not restrict | limited, A well-known method is employable. For example, after mixing each said component, it can prepare by stirring by a well-known means.

[Adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet obtained from the above-described composition of the present invention.
Although the thickness in particular of an adhesive sheet is not restrict | limited, It is preferable that it is 5-2500 micrometers, It is more preferable that it is 50-500 micrometers, It is further more preferable that it is 100-250 micrometers.
The pressure-sensitive adhesive sheet is preferably optically transparent. That is, it is preferably a transparent adhesive sheet. Optically transparent means that the total light transmittance is 85% or more, preferably 90% or more, and more preferably 95% or more.

<Method for producing adhesive sheet>
The manufacturing method in particular of an adhesive sheet is not restrict | limited, It can manufacture from a well-known method. For example, there is a method in which the composition of the present invention described above is applied on a predetermined substrate (for example, a release sheet such as release PET) and cured by irradiation with light (ultraviolet rays, visible rays, X-rays, etc.). Can be mentioned.
Examples of the method for applying the composition include a gravure coater, a comma coater, a bar coater, a knife coater, a die coater, and a roll coater.
Examples of the light irradiation method include a method using a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, a Deep-UV light, a xenon lamp, a chemical lamp, and a carbon arc lamp. The energy of light irradiation is not particularly limited, but is preferably ¹ to 10 J / cm ² .
After forming the pressure-sensitive adhesive sheet, if necessary, a release sheet such as release PET may be laminated on the exposed surface of the formed pressure-sensitive adhesive sheet.

  In addition, even if the adhesive sheet is a type that does not have a base material (base material-less adhesive sheet), it has a base material in which an adhesive layer is disposed on at least one main surface of the base material (adhesive sheet with a base material) For example, a double-sided pressure-sensitive adhesive sheet with a base material having a pressure-sensitive adhesive layer on both sides of the base material, or a single-sided pressure-sensitive adhesive sheet with a base material having a pressure-sensitive adhesive layer only on one side of the base material may be used.

[Laminate for touch panel, capacitive touch panel]
The laminated body for touchscreens of this invention is equipped with the adhesive sheet of this invention mentioned above, and a capacitive touch panel sensor.
One embodiment of the laminate for a touch panel of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing one embodiment of the laminate for a touch panel of the present invention. In FIG. 1, the laminated body 100 for a touch panel includes an adhesive sheet 12 and a capacitive touch panel sensor 18.
Moreover, FIG. 2 is sectional drawing which represents typically another aspect of the laminated body for touchscreens of this invention. In FIG. 2, the laminate for touch panel 200 includes a protective substrate 20, an adhesive sheet 12, and a capacitive touch panel sensor 18.

Moreover, the capacitive touch panel of this invention is equipped with a capacitive touch panel sensor, the adhesive sheet of this invention mentioned above, and a display apparatus in this order.
One embodiment of the capacitive touch panel of the present invention will be described with reference to the drawings.
FIG. 3A is a cross-sectional view schematically illustrating one embodiment of the capacitive touch panel of the present invention. In FIG. 3A, the capacitive touch panel 300 includes a capacitive touch panel sensor 18, an adhesive sheet 12, and a display device 50.
FIG. 3B is a cross-sectional view schematically showing another aspect of the capacitive touch panel of the present invention. In FIG. 3B, the capacitive touch panel 400 includes the protective substrate 20, the adhesive sheet 12, the capacitive touch panel sensor 18, the adhesive sheet 12, and the display device 50.
Hereinafter, various members used in the laminate for a touch panel and the capacitive touch panel will be described in detail.
FIG. 3C is a cross-sectional view schematically showing still another aspect of the capacitive touch panel of the present invention. In FIG. 3C, the capacitive touch panel 500 includes a protective substrate integrated capacitive touch panel sensor 60, an adhesive sheet 12, and a display device 50. Here, the protective substrate integrated capacitive touch panel sensor 60 is a member in which a protective substrate and a capacitive touch panel sensor are integrated, as will be described later. There is no adhesive sheet in between. Therefore, the capacitive touch panel 500 including the protective substrate integrated capacitive touch panel sensor 60 is thinner than the capacitive touch panel 400 described above.

[Capacitive touch panel sensor]
The capacitive touch panel sensor 18 is arranged on the display device (operator side) and uses a change in capacitance that occurs when an external conductor such as a human finger comes into contact (approaching). This is a sensor that detects the position of an external conductor such as a finger.
The configuration of the capacitive touch panel sensor 18 is not particularly limited, but usually has a detection electrode (especially, a detection electrode extending in the X direction and a detection electrode extending in the Y direction), and the static electricity of the detection electrode in contact with or close to the finger. The coordinates of the finger are specified by detecting the change in capacitance.

The suitable aspect of the electrostatic capacitance type touch panel sensor 18 is explained in full detail using FIG.
FIG. 4 shows a plan view of the capacitive touch panel sensor 180. FIG. 5 is a cross-sectional view taken along the cutting line AA in FIG. The capacitive touch panel sensor 180 includes a substrate 22, a first detection electrode 24 disposed on one main surface (surface) of the substrate 22, a first lead-out wiring 26, and the other main surface of the substrate 22. A second detection electrode 28, a second lead-out wiring 30, and a flexible printed wiring board 32 are provided on the upper side (on the back surface). The region where the first detection electrode 24 and the second detection electrode 28 are provided constitutes an input region E _I (an input region (sensing unit) capable of detecting the contact of an object) that can be input by the user, and input. A first lead wiring 26, a second lead wiring 30 and a flexible printed wiring board 32 are arranged in the outer region E _O located outside the region E _I.
Below, the said structure is explained in full detail.

The substrate 22 plays a role of supporting the first detection electrode 24 and the second detection electrode 28 in the input region E _I and plays a role of supporting the first lead wiring 26 and the second lead wiring 30 in the outer region E _O. It is a member.
The substrate 22 preferably transmits light appropriately. Specifically, the total light transmittance of the substrate 22 is preferably 85 to 100%.
The substrate 22 preferably has an insulating property (is an insulating substrate). That is, the substrate 22 is a layer for ensuring insulation between the first detection electrode 24 and the second detection electrode 28.

The substrate 22 is preferably a transparent substrate (particularly a transparent insulating substrate). Specific examples thereof include an insulating resin substrate, a ceramic substrate, and a glass substrate. Among these, an insulating resin substrate is preferable because of its excellent toughness.
More specifically, the material constituting the insulating resin substrate is polyethylene terephthalate, polyethersulfone, polyacrylic resin, polyurethane resin, polyester, polycarbonate, polysulfone, polyamide, polyarylate, polyolefin, cellulose resin, poly Examples include vinyl chloride and cycloolefin resins. Among these, polyethylene terephthalate, cycloolefin resin, polycarbonate, and triacetyl cellulose resin are preferable because of excellent transparency.

In FIG. 4, the substrate 22 is a single layer, but may be a multilayer of two or more layers.
The thickness of the substrate 22 (when the substrate 22 is a multilayer of two or more layers is not particularly limited), it is preferably 5 to 350 μm, and more preferably 30 to 150 μm. Within the above range, desired visible light transmittance can be obtained, and handling is easy.
Moreover, in FIG. 4, the planar view shape of the board | substrate 22 is substantially rectangular shape, However, It is not restricted to this. For example, it may be circular or polygonal.

The first detection electrode 24 and the second detection electrode 28 are sensing electrodes that sense a change in capacitance, and constitute a sensing unit (sensor unit). That is, when the fingertip is brought into contact with the touch panel, the mutual capacitance between the first detection electrode 24 and the second detection electrode 28 changes, and the position of the fingertip is calculated by the IC circuit based on the change amount.
First detection electrode 24, which has a role to detect the input position in the X direction of the finger of the user in proximity to the input region E _I, has the function of generating an electrostatic capacitance between the finger ing. The first detection electrodes 24 are electrodes that extend in a first direction (X direction) and are arranged at a predetermined interval in a second direction (Y direction) orthogonal to the first direction. Includes patterns.
The second detection electrode 28 has a role of detecting the input position in the Y direction of the user's finger approaching the input area E _I and has a function of generating a capacitance between the second detection electrode 28 and the finger. ing. The second detection electrodes 28 are electrodes that extend in the second direction (Y direction) and are arranged at a predetermined interval in the first direction (X direction), and include a predetermined pattern as will be described later. In FIG. 4, five first detection electrodes 24 and five second detection electrodes 28 are provided, but the number is not particularly limited and may be plural.

  In FIG. 4, the first detection electrode 24 and the second detection electrode 28 are configured by conductive thin wires. FIG. 6 shows an enlarged plan view of a part of the first detection electrode 24. As shown in FIG. 6, the first detection electrode 24 is composed of conductive thin wires 34, and includes a plurality of gratings 36 formed of intersecting conductive thin wires 34. Note that, similarly to the first detection electrode 24, the second detection electrode 28 also includes a plurality of lattices 36 formed by intersecting conductive thin wires 34.

  Examples of the material of the conductive thin wire 34 include metals and alloys such as gold (Au), silver (Ag), copper (Cu), and aluminum (Al), ITO, tin oxide, zinc oxide, cadmium oxide, gallium oxide, Examples thereof include metal oxides such as titanium oxide. Among these, silver is preferable because the conductivity of the conductive thin wire 34 is excellent.

The conductive fine wire 34 preferably contains a binder from the viewpoint of adhesion between the conductive fine wire 34 and the substrate 22.
The binder is preferably a water-soluble polymer because the adhesion between the conductive thin wire 34 and the substrate 22 is more excellent. Examples of binders include gelatin, carrageenan, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), starch and other polysaccharides, cellulose and its derivatives, polyethylene oxide, polysaccharides, polyvinylamine, chitosan, polylysine, and polyacryl. Examples include acid, polyalginic acid, polyhyaluronic acid, carboxycellulose, gum arabic, and sodium alginate. Among these, gelatin is preferable because the adhesion between the conductive thin wire 34 and the substrate 22 is more excellent.
In addition to lime-processed gelatin, acid-processed gelatin may be used as gelatin, and gelatin hydrolyzate, gelatin enzyme decomposition product, and other gelatins modified with amino groups and carboxyl groups (phthalated gelatin, acetylated gelatin) Can be used.

As the binder, a polymer different from the above gelatin (hereinafter also simply referred to as a polymer) may be used together with gelatin.
The type of polymer used is not particularly limited as long as it is different from gelatin. For example, acrylic resin, styrene resin, vinyl resin, polyolefin resin, polyester resin, polyurethane resin, polyamide resin, polycarbonate resin , A polydiene resin, an epoxy resin, a silicone resin, a cellulose polymer, and a chitosan polymer, or at least one resin selected from the group consisting of: Examples include coalescence.

The volume ratio of metal to binder (metal volume / binder volume) in the conductive thin wire 34 is preferably 1.0 or more, and more preferably 1.5 or more. By setting the volume ratio of the metal and the binder to 1.0 or more, the conductivity of the conductive thin wire 34 can be further increased. The upper limit is not particularly limited, but is preferably 6.0 or less, more preferably 4.0 or less, and even more preferably 2.5 or less from the viewpoint of productivity.
The volume ratio of the metal and the binder can be calculated from the density of the metal and the binder contained in the conductive thin wire 34. For example, when the metal is silver, the density of silver is 10.5 g / cm ³ , and when the binder is gelatin, the density of gelatin is 1.34 g / cm ³ .

Although the line width of the conductive thin wire 34 is not particularly limited, it is preferably 30 μm or less, more preferably 15 μm or less, further preferably 10 μm or less, and particularly preferably 9 μm or less, from the viewpoint that a low-resistance electrode can be formed relatively easily. 7 μm or less is most preferable, 0.5 μm or more is preferable, and 1.0 μm or more is more preferable.
The thickness of the conductive thin wire 34 is not particularly limited, but can be selected from 0.00001 mm to 0.2 mm from the viewpoint of conductivity and visibility, but is preferably 30 μm or less, more preferably 20 μm or less, 0.01 -9 μm is more preferable, and 0.05-5 μm is most preferable.

The lattice 36 includes an opening region surrounded by the thin conductive wires 34. The length W of one side of the grating 36 is preferably 800 μm or less, more preferably 600 μm or less, and preferably 400 μm or more.
In the first detection electrode 24 and the second detection electrode 28, the aperture ratio is preferably 85% or more, more preferably 90% or more, and most preferably 95% or more in terms of visible light transmittance. preferable. The aperture ratio corresponds to the ratio of the transmissive portion excluding the conductive thin wires 34 in the first detection electrode 24 or the second detection electrode 28 in the predetermined region.

The lattice 36 has a substantially rhombus shape. However, other polygonal shapes (for example, a triangle, a quadrangle, and a hexagon) may be used. Further, the shape of one side may be a curved shape or a circular arc shape in addition to a linear shape. In the case of the arc shape, for example, the two opposing sides may have an outwardly convex arc shape, and the other two opposing sides may have an inwardly convex arc shape. The shape of each side may be a wavy shape in which an outwardly convex arc and an inwardly convex arc are continuous. Of course, the shape of each side may be a sine curve.
In FIG. 6, the conductive thin wire 34 is formed as a mesh pattern, but is not limited to this mode, and may be a stripe pattern.

The first lead wiring 26 and the second lead wiring 30 are members that play a role in applying a voltage to the first detection electrode 24 and the second detection electrode 28, respectively.
The first lead wiring 26 is disposed on the substrate 22 in the outer region E _O , one end of which is electrically connected to the corresponding first detection electrode 24, and the other end is electrically connected to the flexible printed wiring board 32. The
The second lead wiring 30 is disposed on the substrate 22 in the outer region E _O , one end of which is electrically connected to the corresponding second detection electrode 28, and the other end is electrically connected to the flexible printed wiring board 32. The
In FIG. 4, five first extraction wirings 26 and five second extraction wirings 30 are illustrated, but the number is not particularly limited, and a plurality of the first extraction wirings are usually arranged according to the number of detection electrodes. The

Examples of the material constituting the first lead wiring 26 and the second lead wiring 30 include metals such as gold (Au), silver (Ag), and copper (Cu), tin oxide, zinc oxide, cadmium oxide, and gallium oxide. And metal oxides such as titanium oxide. Among these, silver is preferable because of its excellent conductivity. Moreover, you may be comprised with metal pastes, such as a silver paste and a copper paste, metals, such as aluminum (Al) and molybdenum (Mo), and an alloy thin film. In the case of a metal paste, a screen printing or ink jet printing method is used, and in the case of a metal or alloy thin film, a patterning method such as a photolithography method is suitably used for the sputtered film.
In addition, it is preferable that the binder is contained in the 1st extraction wiring 26 and the 2nd extraction wiring 30 from the point which adhesiveness with the board | substrate 22 is more excellent. The kind of binder is as above-mentioned.

  The flexible printed wiring board 32 is a board in which a plurality of wirings and terminals are provided on a substrate, and is connected to each other end of the first lead wiring 26 and each other end of the second lead wiring 30 to electrostatically It plays a role of connecting the capacitive touch panel sensor 180 and an external device (for example, a display device).

[Manufacturing method of capacitive touch panel sensor]
The manufacturing method of the capacitive touch panel sensor 180 is not particularly limited, and a known method can be adopted. For example, there is a method in which a photoresist film on the metal foil formed on both main surfaces of the substrate 22 is exposed and developed to form a resist pattern, and the metal foil exposed from the resist pattern is etched. Further, there is a method in which a paste containing metal fine particles or metal nanowires is printed on both main surfaces of the substrate 22 and metal plating is performed on the paste. Moreover, the method of printing and forming on the board | substrate 22 with a screen printing plate or a gravure printing plate, or the method of forming by an inkjet is also mentioned.

Furthermore, in addition to the above method, a method using silver halide can be mentioned. More specifically, the step (1) of forming a silver halide emulsion layer (hereinafter also referred to simply as a photosensitive layer) containing silver halide and a binder on both surfaces of the substrate 22, respectively, exposing the photosensitive layer. Then, the method which has the process (2) which carries out image development processing is mentioned.
Below, each process is demonstrated.

<Step (1): Photosensitive layer forming step>
Step (1) is a step of forming a photosensitive layer containing silver halide and a binder on both surfaces of the substrate 22.
The method for forming the photosensitive layer is not particularly limited, but from the viewpoint of productivity, the photosensitive layer forming composition containing silver halide and a binder is brought into contact with the substrate 22, and the photosensitive layer is formed on both surfaces of the substrate 22. The method of forming is preferred.
Below, after explaining in full detail the aspect of the composition for photosensitive layer formation used with the said method, the procedure of a process is explained in full detail.

The photosensitive layer forming composition contains a silver halide and a binder.
The halogen element contained in the silver halide may be any of chlorine, bromine, iodine and fluorine, or a combination thereof. As the silver halide, for example, silver halides mainly composed of silver chloride, silver bromide and silver iodide are preferably used, and silver halides mainly composed of silver bromide and silver chloride are preferably used.
The kind of binder used is as above-mentioned. Moreover, the binder may be contained in the composition for photosensitive layer formation in the form of latex.
The volume ratio of the silver halide and the binder contained in the composition for forming the photosensitive layer is not particularly limited, and is appropriately adjusted so as to be within a preferable volume ratio range of the metal and the binder in the conductive thin wire 34 described above. Is done.

The composition for forming a photosensitive layer contains a solvent, if necessary.
Examples of the solvent used include water, organic solvents (for example, alcohols such as methanol, ketones such as acetone, amides such as formamide, sulfoxides such as dimethyl sulfoxide, esters such as ethyl acetate, ethers, and the like. Etc.), ionic liquids, or mixed solvents thereof.
The content of the solvent used is not particularly limited, but is preferably in the range of 30 to 90% by mass and more preferably in the range of 50 to 80% by mass with respect to the total mass of the silver halide and the binder.

(Process procedure)
The method for bringing the composition for forming a photosensitive layer and the substrate 22 into contact with each other is not particularly limited, and a known method can be adopted. For example, the method of apply | coating the composition for photosensitive layer formation to the board | substrate 22, the method of immersing the board | substrate 22 in the composition for photosensitive layer formation, etc. are mentioned.
The content of the binder in the formed photosensitive layer is not particularly limited but is preferably ^{0.3~5.0g / m 2, 0.5~2.0g / m} 2 is more preferable.
Further, the content of the silver halide in the photosensitive layer is not particularly limited, but is preferably 1.0 to 20.0 g / m ^{2 in} terms of silver in that the conductive characteristics of the conductive fine wire 34 are more excellent. 0-15.0 g / m < ² > is more preferable.

  In addition, you may further provide the protective layer which consists of a binder on a photosensitive layer as needed. By providing the protective layer, scratches can be prevented and mechanical properties can be improved.

<Process (2): Exposure development process>
In the step (2), the photosensitive layer obtained in the above step (1) is subjected to pattern exposure and then developed to thereby perform the first detection electrode 24 and the first lead wiring 26, and the second detection electrode 28 and the second detection electrode 28. This is a step of forming two lead-out wirings 30.
First, the pattern exposure process will be described in detail below, and then the development process will be described in detail.

(Pattern exposure)
By subjecting the photosensitive layer to pattern exposure, the silver halide in the photosensitive layer in the exposed region forms a latent image. In the area where the latent image is formed, conductive thin lines are formed by a development process described later. On the other hand, in an unexposed area that has not been exposed, the silver halide dissolves and flows out of the photosensitive layer during the fixing process described later, and a transparent film is obtained.
The light source used in the exposure is not particularly limited, and examples thereof include light such as visible light and ultraviolet light, and radiation such as X-rays.
The method for performing pattern exposure is not particularly limited. For example, surface exposure using a photomask may be performed, or scanning exposure using a laser beam may be performed. The shape of the pattern is not particularly limited, and is appropriately adjusted according to the pattern of the conductive fine wire to be formed.

(Development processing)
The development processing method is not particularly limited, and a known method can be employed. For example, a usual development processing technique used for silver salt photographic film, photographic paper, film for printing plate making, emulsion mask for photomask, and the like can be used.
The type of the developer used in the development process is not particularly limited. For example, PQ developer, MQ developer, MAA developer and the like can be used. Commercially available products include, for example, CN-16, CR-56, CP45X, FD-3, Papitol, C-41, E-6, RA-4, D-19, D-72 prescribed by KODAK. Or a developer contained in a kit thereof can be used. A lith developer can also be used.
The development process can include a fixing process performed for the purpose of removing and stabilizing the silver salt in the unexposed part. For the fixing process, a technique of fixing process used for silver salt photographic film, photographic paper, film for printing plate making, emulsion mask for photomask, and the like can be used.
The fixing temperature in the fixing step is preferably about 20 ° C. to about 50 ° C., and more preferably 25 to 45 ° C. The fixing time is preferably 5 seconds to 1 minute, and more preferably 7 seconds to 50 seconds.
The mass of the metallic silver contained in the exposed area (conductive thin wire) after the development treatment is preferably a content of 50% by mass or more based on the mass of silver contained in the exposed area before the exposure, More preferably, it is at least mass%. If the mass of silver contained in the exposed portion is 50% by mass or more based on the mass of silver contained in the exposed portion before exposure, it is preferable because high conductivity can be obtained.

In addition to the above steps, the following undercoat layer forming step, antihalation layer forming step, or heat treatment may be performed as necessary.
(Undercoat layer forming process)
For the reason of excellent adhesion between the substrate 22 and the silver halide emulsion layer, it is preferable to perform a step of forming an undercoat layer containing the binder on both sides of the substrate 22 before the step (1).
The binder used is as described above. The thickness of the undercoat layer is not particularly limited, but is preferably from 0.01 to 0.5 μm, more preferably from 0.01 to 0.1 μm, in that the adhesiveness and the change rate of mutual capacitance are further suppressed.
(Anti-halation layer formation process)
From the viewpoint of thinning the conductive thin wire 34, it is preferable to carry out a step of forming antihalation layers on both surfaces of the substrate 22 before the step (1).

<Process (3): Heating process>
Step (3) is a step of performing heat treatment after the development processing. By performing this step, fusion occurs between the binders, and the hardness of the conductive thin wires 34 is further increased. In particular, when polymer particles are dispersed as a binder in the composition for forming a photosensitive layer (when the binder is polymer particles in latex), by performing this step, fusion occurs between the polymer particles, Conductive thin wires 34 having a desired hardness are formed.
The conditions for the heat treatment are appropriately selected depending on the binder used, but it is preferably 40 ° C. or higher from the viewpoint of the film forming temperature of the polymer particles, more preferably 50 ° C. or higher, and further 60 ° C. or higher. preferable. Further, from the viewpoint of suppressing curling of the substrate and the like, 150 ° C. or lower is preferable, and 100 ° C. or lower is more preferable.
The heating time is not particularly limited, but is preferably 1 to 5 minutes and more preferably 1 to 3 minutes from the viewpoint of suppressing curling of the substrate and the productivity.
In addition, since this heat treatment can be combined with a drying step usually performed after exposure and development processing, it is not necessary to increase a new step for film formation of polymer particles, and productivity, cost, etc. Excellent from a viewpoint.

In addition, by performing the said process, the light transmissive part containing a binder is formed between the electroconductive thin wires 34. FIG. The transmittance in the light transmissive part is preferably 90% or more, more preferably 95% or more, still more preferably 97% or more, and more preferably 98% or more. Is particularly preferable, and 99% or more is most preferable.
The light transmissive portion may contain materials other than the binder, and examples thereof include a silver difficult solvent.

The aspect of the capacitive touch panel sensor is not limited to the aspect of FIG. 4 described above, and may be another aspect.
For example, as shown in FIG. 7, the capacitive touch panel sensor 280 is electrically connected to the first substrate 38, the second detection electrode 28 disposed on the first substrate 38, and one end of the second detection electrode 28. And electrically connected to one end of the second lead-out wiring (not shown) disposed on the first substrate 38, the adhesive sheet 40, the first detection electrode 24, and the first detection electrode 24. A first lead wire (not shown), a second substrate 42 adjacent to the first detection electrode 24 and the first lead wire, and a flexible printed wiring board (not shown).
As shown in FIG. 7, the capacitive touch panel sensor 280 has the same configuration as the capacitive touch panel sensor 180 except for the first substrate 38, the second substrate 42, and the adhesive sheet 40. Therefore, the same components are denoted by the same reference numerals, and the description thereof is omitted.
The definitions of the first substrate 38 and the second substrate 42 are the same as the definition of the substrate 22 described above.
The pressure-sensitive adhesive sheet 40 is a layer for bringing the first detection electrode 24 and the second detection electrode 28 into close contact with each other, and is preferably optically transparent (preferably a transparent pressure-sensitive adhesive sheet). A known material may be used as the material constituting the pressure-sensitive adhesive sheet 40, and the pressure-sensitive adhesive sheet 12 may be used as the pressure-sensitive adhesive sheet 40.
A plurality of the first detection electrodes 24 and the second detection electrodes 28 in FIG. 7 are used as shown in FIG. 4, and both are arranged so as to be orthogonal to each other as shown in FIG.
In addition, the capacitive touch panel sensor 280 shown in FIG. 7 is prepared by preparing two substrates with electrodes having a substrate and detection electrodes and lead wires arranged on the substrate surface, so that the electrodes face each other. Corresponds to the capacitive touch panel sensor obtained by bonding through the.

As another aspect of the capacitive touch panel sensor, an aspect shown in FIG.
The capacitive touch panel sensor 380 is electrically connected to the first substrate 38, the second detection electrode 28 disposed on the first substrate 38, and one end of the second detection electrode 28. A second lead-out wiring (not shown), an adhesive sheet 40, a second substrate 42, a first detection electrode 24 disposed on the second substrate 42, and one end of the first detection electrode 24; A first lead-out wiring (not shown) and a flexible printed wiring board (not shown) which are electrically connected and are arranged on the second substrate 42 are provided.
The capacitive touch panel sensor 380 shown in FIG. 8 has the same layers as the capacitive touch panel sensor 280 shown in FIG. 7 except that the order of the layers is different. Are denoted by the same reference numerals, and the description thereof is omitted.
Further, a plurality of the first detection electrodes 24 and the second detection electrodes 28 in FIG. 8 are used as shown in FIG. 4, and both are arranged so as to be orthogonal to each other as shown in FIG. .
In addition, the capacitive touch panel sensor 380 shown in FIG. 8 prepares two substrates with electrodes having a substrate and detection electrodes and lead wires arranged on the substrate surface, and the substrate in the substrate with one electrode It corresponds to the electrostatic capacitance type touch panel sensor obtained by bonding through an adhesive sheet so that the electrode of the other board | substrate with an electrode may face.

As another aspect of the capacitive touch panel sensor, for example, in FIG. 4, the conductive thin wires 34 of the first detection electrode 24 and the second detection electrode 28 are made of metal oxide particles, metal such as silver paste or copper paste. You may be comprised with the paste. Among these, a conductive film made of a thin silver wire and a silver nanowire conductive film are preferable in terms of excellent conductivity and transparency.
In addition, the first detection electrode 24 and the second detection electrode 28 are configured by the mesh structure of the conductive thin wires 34. However, the present invention is not limited to this mode. Oxide thin film), and a transparent conductive film in which a network is formed of metal nanowires such as silver nanowires and copper nanowires.
More specifically, as shown in FIG. 9, a capacitive touch panel sensor 180a having a first detection electrode 24a and a second detection electrode 28a made of a transparent metal oxide may be used. FIG. 9 is a partial plan view of the input area of the capacitive touch panel sensor 180a. 10 is a cross-sectional view taken along the cutting line AA in FIG. The capacitive touch panel sensor 180a is electrically connected to the first substrate 38, the second detection electrode 28a disposed on the first substrate 38, and one end of the second detection electrode 28a. A second lead-out wiring (not shown), an adhesive sheet 40, a second substrate 42, a first detection electrode 24a disposed on the second substrate 42, and one end of the first detection electrode 24a. A first lead-out wiring (not shown) and a flexible printed wiring board (not shown) which are electrically connected and are arranged on the second substrate 42 are provided.
The capacitive touch panel sensor 180a shown in FIGS. 9 and 10 has the same layer as the capacitive touch panel sensor 380 shown in FIG. 8 except for the points other than the first detection electrode 24a and the second detection electrode 28a. Therefore, the same components are denoted by the same reference numerals, and the description thereof is omitted.
The capacitive touch panel sensor 180a shown in FIG. 9 and FIG. 10 prepares two substrates with electrodes having a substrate and detection electrodes and lead wires arranged on the substrate surface, and the substrate in the substrate with one electrode This corresponds to a capacitive touch panel sensor obtained by bonding through an adhesive layer so that the electrode on the other electrode-attached substrate faces the electrode.

As described above, the first detection electrode 24a and the second detection electrode 28a are electrodes extending in the X-axis direction and the Y-axis direction, respectively, and are made of a transparent metal oxide, for example, indium tin oxide (ITO). The 9 and 10, in order to make use of the transparent electrode ITO as a sensor, the resistance of the indium tin oxide (ITO) itself is increased, the total wiring resistance is reduced by increasing the electrode area, and the thickness is further increased. It is designed to ensure the light transmittance by making it thinner and taking advantage of the characteristics of the transparent electrode.
In addition to ITO, examples of materials that can be used in the above embodiment include zinc oxide (ZnO), indium zinc oxide (IZO), gallium zinc oxide (GZO), and aluminum zinc oxide (AZO). It is done.
The patterning of the electrode parts (the first detection electrode 24a and the second detection electrode 28a) can be selected according to the material of the electrode part, and a photolithography method, a resist mask screen printing-etching method, an ink jet method, a printing method, etc. It may be used.

[Protection board]
The protective substrate 20 is a substrate disposed on the adhesive sheet, and serves to protect a capacitive touch panel sensor 18 (to be described later) from the external environment, and its main surface constitutes a touch surface.
The protective substrate 20 is preferably a transparent substrate, and a plastic film, a plastic plate, a glass plate, or the like is used. It is desirable that the thickness of the substrate is appropriately selected according to each application.
Examples of the raw material for the plastic film and the plastic plate include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyolefins such as polyethylene (PE), polypropylene (PP), polystyrene, and EVA; Resin; In addition, polycarbonate (PC), polyamide, polyimide, acrylic resin, triacetyl cellulose (TAC), cycloolefin resin (COP), and the like can be used.
Further, as the protective substrate 20, a polarizing plate, a circular polarizing plate, or the like may be used.

[Protective substrate integrated type capacitive touch panel sensor]
The protective substrate integrated capacitive touch panel sensor 60 is a member in which a protective substrate and a capacitive touch panel sensor are integrated.
The method for manufacturing the protective substrate integrated capacitive touch panel sensor 60 is not particularly limited, and examples thereof include a method of directly forming a detection electrode on the protective substrate.

[Display device]
The display device 50 is a device having a display surface for displaying an image, and each member is arranged on the display screen side.
The type of the display device 50 is not particularly limited, and a known display device can be used. For example, cathode ray tube (CRT) display, liquid crystal display (LCD), organic light emitting diode (OLED) display, vacuum fluorescent display (VFD), plasma display panel (PDP), surface field display (SED) or field emission display (FED) or electronic paper (E-Paper).

The above-mentioned pressure-sensitive adhesive sheet of the present invention can be suitably used for the production of a capacitive touch panel. For example, between the display device and the capacitive touch panel sensor, between the capacitive touch panel sensor and a protective substrate, or on the substrate and the substrate in the capacitive touch sensor. It is used to provide an adhesive sheet that is disposed between conductive films provided with detection electrodes.
In particular, the pressure-sensitive adhesive sheet of the present invention is preferably used for providing a pressure-sensitive adhesive layer adjacent to the detection electrode in the capacitive touch panel. When used in such an aspect, it is preferable because touch malfunctions due to the influence of the above-described variation factors can be remarkably reduced.
In addition, as a case where the adhesive sheet is adjacent to the detection electrode, for example, when the capacitive touch panel sensor has a configuration in which the detection electrode is arranged on the back surface of the substrate, the detection electrode is in contact with both detection electrodes. The case where an adhesive sheet is arrange | positioned is mentioned. In another case, the capacitive touch panel sensor has two conductive films each having a substrate and a detection electrode disposed on one side of the substrate, and the two conductive films are detected when bonded. The case where an adhesive sheet is arrange | positioned so that an electrode may be touched is mentioned. More specifically, the case where it uses as an aspect of the adhesive sheet 40 of FIG. 7 and FIG. 8 is mentioned.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

<Examples 1 to 25 and Comparative Examples 1 to 15>
(Preparation of adhesive composition)
Each pressure-sensitive adhesive composition was obtained by mixing the components shown in Table 1 below in the blending amounts (parts by mass) shown in Table 1 below and stirring them. Here, for monomer 1 and monomer 2, the left side of the slash (/) represents the component (the numerical value in parentheses is the SP value of the component), and the right side of the slash (/) represents the compounding amount of the component.
For example, the pressure-sensitive adhesive composition of Example 1 includes EHMA (20 parts by mass), FA-512M (5 parts by mass), TPO (2.4 parts by mass), IRG819 (0.6 parts by mass), In the pressure-sensitive adhesive composition obtained by mixing and stirring UC-203 (21.78 parts by mass), P-135 (38.8 parts by mass), and Polyoil 110 (11.42 parts by mass). is there. Details of each component are as described below.
In the examples and comparative examples other than comparative examples 8 and 14, a homogeneous composition was obtained. On the other hand, in Comparative Examples 8 and 14, IRG819 (Irgacure 819) was not compatible with other components, and a homogeneous composition capable of forming an adhesive sheet was not obtained.

(Preparation of adhesive sheet)
Each obtained adhesive composition was apply | coated on mold release PET, respectively, and the adhesive composition layer was formed. Thereafter, the formed adhesive composition layer was irradiated with a fusion UV lamp (D bulb: illuminance 200 mW / cm ² ) under the condition of ³ J / cm ² and cured to form an adhesive sheet (thickness) formed on the release PET. : 150 μm).
When the obtained pressure-sensitive adhesive sheet was visually observed under a fluorescent lamp, no cloudiness was observed and it was transparent.
In addition, about the adhesive composition of the comparative examples 8 and 14 in which the homogeneous composition was not obtained, preparation of an adhesive sheet was not performed.

<Evaluation of adhesion>
Each obtained pressure-sensitive adhesive sheet was cut into 2.5 cm × 5 cm, and a sample was prepared by sticking one side of the cut-out pressure-sensitive adhesive sheet to a glass substrate and the other side to a Kapton film. Subsequently, one end of the Kapton film was gripped using an autograph manufactured by Shimadzu Corporation, a 180 degree peel test (tensile speed of 300 cm / min) was performed, and an average test force value of the adhesive sheet and the glass substrate was measured. The value was defined as adhesive strength (N / mm). The results are shown in Table 1. Practically, the adhesive strength is preferably 0.60 N / mm or more.

<Evaluation of step following ability>
Each obtained adhesive sheet was cut into 2.5 cm × 4 cm, one side of the cut out adhesive sheet was attached to a glass substrate wrapped with Kapton tape (5 mm width 35 μm thickness), and the other side was attached to optical PET. An attached sample was produced. Subsequently, using an autoclave, a heat press treatment was performed under the conditions of an internal temperature of 40 ° C., 5 atm, and 20 minutes to prepare a sample for a step following test.
About the produced sample, the boundary surface formed between the adhesive sheet and the Kapton tape level | step difference was observed with the Nikon optical microscope, and the boundary space | gap width was measured.
Of the measured boundary gap width, the largest value of less than 20 μm is designated as “A” as having excellent step followability, and those having 20 μm or more but less than 50 μm are designated as “B” having relatively excellent step followability, A material having a thickness of 50 μm or more and less than 100 μm is not preferable, but “C” is used as a practically usable product, and a product having a thickness of 100 μm or more is “D” because it is inferior in level-step following property and has no practicality. The results are shown in Table 1.

<Evaluation of malfunction occurrence rate>
First, the manufacturing method of the touch panel used by evaluation of malfunction occurrence rate is shown below.

(Preparation of silver halide emulsion)
To the following 1 liquid maintained at 38 ° C. and pH 4.5, an amount corresponding to 90% of each of the following 2 and 3 liquids was simultaneously added over 20 minutes while stirring to form 0.16 μm core particles. Subsequently, the following 4 and 5 solutions were added over 8 minutes, and the remaining 10% of the following 2 and 3 solutions were added over 2 minutes to grow to 0.21 μm. Further, 0.15 g of potassium iodide was added and ripened for 5 minutes to complete the grain formation.

1 liquid:
750 ml of water
9g gelatin
Sodium chloride 3g
1,3-Dimethylimidazolidine-2-thione 20mg
Sodium benzenethiosulfonate 10mg
Citric acid 0.7g
Two liquids:
300 ml of water
150 g silver nitrate
3 liquids:
300 ml of water
Sodium chloride 38g
Potassium bromide 32g
Potassium hexachloroiridium (III) (0.005% KCl 20% aqueous solution) 8 ml
Ammonium hexachlororhodate
(0.001% NaCl 20% aqueous solution) 10 ml
4 liquids:
100ml water
Silver nitrate 50g
5 liquids:
100ml water
Sodium chloride 13g
Potassium bromide 11g
Yellow blood salt 5mg

  Then, it washed with water by the flocculation method according to a conventional method. Specifically, the temperature was lowered to 35 ° C., and the pH was lowered using sulfuric acid until the silver halide precipitated (the pH was in the range of 3.6 ± 0.2). Next, about 3 liters of the supernatant was removed (first water washing). Further, 3 liters of distilled water was added, and sulfuric acid was added until the silver halide settled. Again, 3 liters of the supernatant was removed (second water wash). The same operation as the second water washing was further repeated once (third water washing) to complete the water washing / desalting step. The emulsion after washing with water and desalting was adjusted to pH 6.4 and pAg 7.5, and gelatin 3.9 g, sodium benzenethiosulfonate 10 mg, sodium benzenethiosulfinate 3 mg, sodium thiosulfate 15 mg and chloroauric acid 10 mg were added. Chemical sensitization is performed to obtain an optimum sensitivity at 0 ° C., and 100 mg of 1,3,3a, 7-tetraazaindene is added as a stabilizer and 100 mg of proxel (trade name, manufactured by ICI Co., Ltd.) is used as a preservative. It was. The finally obtained emulsion contains 0.08 mol% of silver iodide, and the ratio of silver chlorobromide is 70 mol% of silver chloride and 30 mol% of silver bromide. It was a silver iodochlorobromide cubic grain emulsion having a coefficient of 9%.

(Preparation of photosensitive layer forming composition)
1,3,3a, 7-tetraazaindene 1.2 × 10 ⁻⁴ mol / mol Ag, hydroquinone 1.2 × 10 ⁻² mol / mol Ag, citric acid 3.0 × 10 ⁻⁴ mol / Mole Ag, 2,4-dichloro-6-hydroxy-1,3,5-triazine sodium salt 0.90 g / mole Ag was added, and the coating solution pH was adjusted to 5.6 using citric acid, and the photosensitivity was obtained. A composition for forming a conductive layer was obtained.

(Photosensitive layer forming step)
After a polyethylene terephthalate (PET) film having a thickness of 100 μm is subjected to corona discharge treatment, a gelatin layer having a thickness of 0.1 μm as an undercoat layer on both sides of the PET film, and an optical density of about 1.0 on the undercoat layer. And an antihalation layer containing a dye which is decolorized by alkali in the developer. On the antihalation layer, the composition for forming a photosensitive layer was applied, a gelatin layer having a thickness of 0.15 μm was further provided, and a PET film having a photosensitive layer formed on both sides was obtained. The obtained film is referred to as film A. The formed photosensitive layer had a silver amount of 6.0 g / m ² and a gelatin amount of 1.0 g / m ² .

(Exposure development process)
As shown in FIG. 4, a high voltage is applied through a photomask in which detection electrodes (first detection electrodes and second detection electrodes) and lead wires (first lead wires and second lead wires) are arranged on both surfaces of the film A. Exposure was performed using parallel light using a mercury lamp as a light source. After exposure, the film was developed with the following developer, and further developed using a fixer (trade name: N3X-R for CN16X, manufactured by Fuji Film). Furthermore, by rinsing with pure water and drying, a capacitive touch panel sensor A provided with detection electrodes and lead wires made of Ag fine wires on both sides was obtained.
In the obtained capacitive touch panel sensor A, the detection electrodes are composed of conductive thin wires that intersect in a mesh shape. Further, as described above, the first detection electrode is an electrode extending in the X direction, and the second detection electrode is an electrode extending in the Y direction, and each is disposed on the film at a pitch of 4.5 to 5 mm.

Next, using each obtained adhesive sheet, a touch panel including a liquid crystal display device, a lower adhesive layer, a capacitive touch panel sensor, an upper adhesive layer, and a glass substrate in this order was manufactured. In addition, as a capacitive touch panel sensor, the capacitive touch panel sensor A manufactured above was used.
Specifically, the adhesive sheet (having the release PET on one side) and the capacitive touch panel sensor A, the surface of the adhesive sheet opposite to the surface having the release PET and one of the capacitive touch panel A The upper adhesive layer was formed by pasting using a 2 kg heavy roller so that the surface of the upper surface would face. Furthermore, the release PET of the pressure-sensitive adhesive sheet was peeled off, and a glass substrate of the same size was bonded onto the upper pressure-sensitive adhesive layer in the same manner using a 2 kg heavy roller. Then, it was exposed to the environment of 40 degreeC and 5 atmospheres for 20 minutes in the high-pressure thermostat, and the defoaming process was performed.
Next, following the same procedure as the formation of the upper adhesive layer, an adhesive sheet (having a release PET on one side) is bonded to the surface opposite to the surface on which the upper adhesive layer of the capacitive touch panel A is formed, A lower adhesive layer was formed. Furthermore, the release PET of the pressure-sensitive adhesive sheet was peeled off, and a liquid crystal display device was attached on the lower pressure-sensitive adhesive layer. Then, it was exposed to the environment of 40 degreeC and 5 atmospheres for 20 minutes in the high-pressure thermostat, and the defoaming process was performed. Thus, the touch panel was manufactured.

The obtained touch panel was heated in steps of 20 ° C. from −40 ° C. to 80 ° C., and the malfunction occurrence rate at the time of touch at each temperature was obtained. That is, in an environment of −40 ° C., −20 ° C., 0 ° C., 20 ° C., 40 ° C., 60 ° C., and 80 ° C., an arbitrary location is touched 100 times and the touch panel The occurrence rate of malfunction (%) [(number of times of not reacting normally / 100) × 100] was determined.
Among the obtained malfunction occurrence rates at each temperature, the highest value of less than 5% is regarded as “A” as the malfunction occurrence rate is very low, and the malfunction occurrence rate is relatively high when the malfunction occurrence rate is 5% or more and less than 10%. “B” as low and “C” as 10% or less and less than 15% as “C” as a relatively high malfunction occurrence rate, and “D” as 15% or more as a very high malfunction occurrence rate. did. The results are shown in Table 1.

In Table 1, “b / a” means “the solubility parameter (SP value) is 8.0 to 10.0, and a branched alkyl group and an alicyclic hydrocarbon group (however, an unsaturated hydrocarbon group). Content (b) of a radically polymerizable monomer (B) having at least one group selected from the group consisting of: an alicyclic hydrocarbon group having a monovalent phosphine oxide (A1) and bis The mass ratio (b / a) to the total content (a) of the acylphosphine oxide (A2) is represented. Of the monomers listed in Table 1, EHMA, CHMA, IBXA and IBX correspond to the above-mentioned radical polymerizable monomer (B), and HEMA, MMA, FA-512M, FA-512AS, EHA and StMA are the above-mentioned radical polymerization. It does not fall under the sex monomer (B).
In Table 1, “O / C ratio” represents the ratio between the number of moles of oxygen atoms and the number of moles of carbon atoms contained in the pressure-sensitive adhesive composition (number of moles of oxygen atoms / number of moles of carbon atoms).

The detail of each component of the said Table 1 is as follows.
EHMA: 2-ethylhexyl methacrylate (SP value: 8.1)
CHMA: cyclohexyl methacrylate (SP value: 8.3)
IBXA: isobornyl acrylate (SP value: 8.33)
-HEMA: 2-hydroxyethyl methacrylate (SP value: 9.39)
MMA: Methyl methacrylate (SP value: 8.2)
FA-512M: dicyclopentenyloxyethyl methacrylate, manufactured by Hitachi Chemical Co., Ltd. FA-512AS: dicyclopentenyloxyethyl acrylate, manufactured by Hitachi Chemical Co., Ltd. EHA: 2-ethylhexyl acrylate (SP value: 7.8)
IBX: isobornyl methacrylate (SP value: 8.3)
StMA: Stearyl methacrylate TPO: Lucirin TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide, manufactured by BASF) (absorbance at 400 nm of 0.1% by weight acetonitrile solution: 1.0)
TPO-L: Lucirin TPO-L (2,4,6-trimethylbenzoyl-phenylethoxyphosphine oxide, manufactured by BASF) (absorbance at 400 nm of 0.1 mass% acetonitrile solution: 0.4)
IRG819: Irgacure 819 (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, manufactured by BASF) (absorbance at 430 nm of 0.1% by mass acetonitrile solution: 0.25)
IRG369: Irgacure 369 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, manufactured by BASF)
IRG184: Irgacure 184 (1-hydroxy-cyclohexyl-phenyl-ketone, manufactured by BASF)
Dye-T: thiochromanone compound (the following compound)
TPP: Triphenyl phosphite DDT: 1-dodecanethiol UC-203: Liquid rubber (esterified product of maleic anhydride adduct of isoprene polymer and 2-hydroxyethyl methacrylate, number of methacryloyl groups per molecule: 3, weight average molecular weight: 35000, manufactured by Kuraray Co., Ltd.)
UC-102: Liquid rubber (esterified product of maleic anhydride adduct of isoprene polymer and 2-hydroxyethyl methacrylate, number of methacryloyl groups per molecule: 2, weight average molecular weight: 19000, manufactured by Kuraray Co., Ltd.)
-P-135: CLEARON P-135 (hydrogenated terpene resin, manufactured by Yasuhara Chemical Co., Ltd.)
Polyoil 110: Liquid polybutadiene (manufactured by Nippon Zeon)

As can be seen from Table 1, in addition to monoacylphosphine oxide (A1), bisacylphosphine oxide (A2) is used in combination, a specific radical polymerizable monomer (B) is used, and the O / C ratio is specified. The adhesive compositions of Examples 1 to 25 showed excellent adhesion when used as adhesive sheets. In addition, when used as an adhesive sheet for a capacitive touch panel, the occurrence of malfunctions was suppressed in a wide temperature environment from low to high temperatures.
From the comparison of Examples 1 to 3, the mass ratio (a2 / a1) of the content (a2) of the bisacylphosphine oxide (A2) and the content (a1) of the monoacylphosphine oxide (A1) is 0.30 or more. Examples 2 and 3, which are the above, exhibited better adhesion and step following ability. Especially, Example 3 whose mass ratio (a2 / a1) was 0.40 or more showed the further outstanding adhesiveness.
From the comparison of Examples 3 to 5, the mass of the content (b) of the radical polymerizable monomer (B) and the total content (a) of the monoacylphosphine oxide (A1) and the bisacylphosphine oxide (A2). Examples 3 and 4 having a ratio (b / a) of 4.0 or more exhibited better adhesion and step following ability. In addition, from the comparison of Examples 3 to 4 and 17 to 18, Examples 3 and 17 having a mass ratio (b / a) of 6.0 or more show further excellent step following performance and more malfunctions occur. It was suppressed.

On the other hand, Comparative Examples 1 to 5 and 7 using only the monoacylphosphine oxide (A1) without using the monoacylphosphine oxide (A1) and the bisacylphosphine oxide (A2) together have insufficient adhesion. there were. In addition, the malfunction occurrence rate may be high.
In Comparative Example 8 using only bisacylphosphine oxide (A2), a homogeneous composition capable of forming an adhesive sheet was not obtained.
Moreover, although the monoacylphosphine oxide (A1) and the bisacylphosphine oxide (A2) are used in combination, Comparative Examples 11 to 13 and 15 that do not use the specific radical polymerizable monomer (B) have insufficient adhesion, Moreover, the malfunction occurrence rate was high.
Moreover, monoacylphosphine oxide (A1) and bisacylphosphine oxide (A2) are used in combination, and a specific radical polymerizable monomer (B) is used, but the mass ratio (b / a) is less than 3.0. In Comparative Example 14, a homogeneous composition capable of forming an adhesive sheet could not be obtained.
In addition, the monoacylphosphine oxide (A1) and the bisacylphosphine oxide (A2) are used in combination, and the specific radical polymerizable monomer (B) is used. In Comparative Example 6 in which the amount was less than 1.5% by mass, the adhesion was insufficient and the malfunction occurrence rate was high.

12 Adhesive sheets 18, 180, 180 a, 280, 380 Capacitive touch panel sensor 20 Protective substrate 22 Substrate 24, 24 a First detection electrode 26, 26 a First extraction wiring 28, 28 a Second detection electrode 30 Second extraction wiring 32 Flexible printed wiring board 34 Conductive thin wire 36 Grid 38 First substrate 40 Adhesive sheet 42 Second substrate 50 Display device 60 Integrated protective substrate capacitive touch panel sensor 100, 200 Laminate 300, 400, 500 for touch panel Capacitance Touch panel

Claims (10)

A pressure-sensitive adhesive composition containing monoacylphosphine oxide A1, bisacylphosphine oxide A2, and radical polymerizable monomer B having a solubility parameter of 8.0 to 10.0,
The radical polymerizable monomer B has at least one group selected from the group consisting of a branched alkyl group and an alicyclic hydrocarbon group,
The content of the monoacylphosphine oxide A1 with respect to the total amount of the pressure-sensitive adhesive composition is 1.5% by mass or more,
The mass ratio b / a of the content b of the radical polymerizable monomer B and the total content a of the monoacylphosphine oxide A1 and the bisacylphosphine oxide A2 is 3.0 to 30.0,
The pressure-sensitive adhesive composition, wherein the ratio of the number of moles of oxygen atoms and the number of moles of carbon atoms contained in the pressure-sensitive adhesive composition is 0.1 or less.
However, the alicyclic hydrocarbon group is an alicyclic hydrocarbon group other than the alicyclic hydrocarbon group having an unsaturated hydrocarbon group. The ratio of the number of moles of oxygen atoms to the number of moles of carbon atoms is the ratio of the number of moles of oxygen atoms to the number of moles of carbon atoms.   The pressure-sensitive adhesive composition according to claim 1, further comprising at least one photopolymerization initiator selected from the group consisting of an aminoketone photopolymerization initiator and a hydroxyketone photopolymerization initiator. Furthermore, the adhesive composition of Claim 1 or 2 containing the sensitizing dye represented by the following general formula (I).
In the general formula (I), R _{11 to} R ₁₈ are each independently a hydrogen atom, alkyl group, halogen atom, hydroxy group, cyano group, nitro group, amino group, alkylthio group, alkylamino group, alkoxy group, alkoxy group. A carbonyl group, an acyloxy group, an acyl group, a carboxyl group or a sulfo group is represented. R ₁₅ or R ₁₆ and R ₁₇ or R ₁₈ may be bonded to each other to form a 5- to 6-membered aliphatic ring, aromatic ring, or heterocyclic ring.   Furthermore, the adhesive composition of any one of Claims 1-3 containing the at least 1 sort (s) of polymerization inhibition inhibitor selected from the group which consists of a phosphite, an amine, and a thiol.   The adhesive sheet obtained from the adhesive composition of any one of Claims 1-4.   The pressure sensitive adhesive sheet according to claim 5 whose thickness is 50 micrometers or more.   The pressure-sensitive adhesive sheet according to claim 5 or 6, which is a pressure-sensitive adhesive sheet for a touch panel.   A laminate for a touch panel comprising the pressure-sensitive adhesive sheet according to claim 7 and a capacitive touch panel sensor. In addition, with a protective substrate,
The laminated body for touchscreens of Claim 8 provided with the said protective substrate, the said adhesive sheet, and the said capacitive touch panel sensor in this order.   An electrostatic capacitance type touch panel provided with an electrostatic capacitance type touch panel sensor, the adhesive sheet according to claim 7, and a display device in this order.