JP5719317B2 - Adhesive composition for conductive film, laminate, and touch panel having the laminate - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition for a conductive film having a specific composition, a laminate for a touch panel forming member using the pressure-sensitive adhesive composition for a conductive film as a pressure-sensitive adhesive, and a touch panel having the laminate.

  At present, the touch panel units mainly used are roughly classified into a resistance film type touch panel and a capacitance type touch panel, both of which are laminates of various materials. System adhesive is used. Since the touch panel unit is placed on the outermost surface of the screen, the acrylic adhesive used must have high transparency, and it can be placed in a high-temperature and high-humidity environment in durability tests and accelerated tests. Characteristics such as high heat resistance and moist heat resistance are required.

  Specifically, the touch panel unit, which is a laminate of various materials, is disposed on the outermost surface of the touch panel device, and may cause whitening due to the ingress of moisture from the outside. When sticking together with a pressure-sensitive adhesive, there is a problem that poor appearance is caused by foaming by entraining air and foaming by outgas generated from the material to be laminated.

  Moreover, in the resistive film type touch panel which has been the mainstream of touch panels so far, various adhesives have been used for attaching polycarbonate (PC) or in-mold film (IMD).

  However, as a characteristic of the PC material, outgas is generated under high temperature conditions, and since PC easily passes moisture, foaming occurs under heat resistant conditions, and the whitening phenomenon of the adhesive layer due to moisture inflow under wet heat conditions is suppressed. There is also the problem that it is difficult. Furthermore, since the IMD has a step of the order of sub-micron, there is a problem that the adhesive cannot follow the step and bubbles are involved.

  Conventionally, the above problems have been solved by adding an acid component to the pressure-sensitive adhesive. In other words, the acid component has the function of dispersing the mixed water and preventing it from being deposited, and the water that has entered the pressure-sensitive adhesive layer is dispersed and not precipitated in the pressure-sensitive adhesive layer by the dispersion force of the acid component. The pressure-sensitive adhesive layer was prevented from being whitened and also formed with hydrogen bonds, so the generation of bubbles in heat-resistant foaming was suppressed by the high cohesive force due to the hydrogen bonds.

  Recently, with the enhancement of functions such as multi-touch, capacitive touch panels are becoming the mainstream instead of resistive touch panels. In this capacitive touch panel, the characteristics required for the resistive touch panel are of course necessary, but in addition, because the adhesive is in direct contact with the conductive layer forming the wiring, The property that the adhesive does not change the properties of the conductive layer is required. The conductive layer is made of a metal or metal oxide, such as indium tin oxide (ITO), which causes corrosion due to contact with acid and increases its resistance value. It is not possible to use means for securing characteristics such as heat resistance and heat-and-moisture resistance using

  Regarding the corrosion of such transparent electrodes made of metals such as ITO or metal oxides, Patent Document 1 (Japanese Patent Laid-Open No. 2010-77287) discloses a polymer mainly composed of alkoxyalkyl acrylate. In this Patent Document 1, it is disclosed to use an alkoxyalkyl acrylate polymer having a weight average molecular weight of 400,000 to 1.6 million and not using a carboxyl group-containing monomer.

  Thus, by using 400,000 to 1.6 million alkoxyalkyl acrylate polymers without using carboxyl group-containing monomers, the corrosion of transparent electrodes made of metals such as ITO or metal oxides is improved to some extent. However, sufficient effects have not been obtained with respect to performance such as heat-and-moisture whitening resistance and heat-resistant foaming resistance. Furthermore, it cannot be said that the workability when the adhesive is applied to a transparent electrode or the like is sufficient.

  Furthermore, since the weight average molecular weight of the polymer disclosed in Patent Document 1 is as large as 400,000 to 1.6 million, the viscosity of the polymer solution increases when the solid content increases when this is dissolved in a solvent to prepare a coating solution. Is too high. In touch panel applications, especially capacitive touch panel applications, a thick adhesive layer is used to bond the surface support to a conductive film such as ITO and to increase the sensitivity to detect changes in capacitance. Need to form. However, since an application liquid having a high solid content cannot be prepared by using an alkoxyalkyl acrylate polymer having a weight average molecular weight of 400,000 to 1.6 million, a preparation liquid having a low solid content is prepared. There is a problem that it is necessary to repeatedly apply, and it is difficult to form a pressure-sensitive adhesive layer having a thickness required for one coating.

  Patent Document 2 (Patent No. 4531099) discloses a weight average molecular weight of 400,000 to 1.6 million obtained by copolymerizing an alkoxyalkyl acrylate and an acrylic monomer having a hydroxyl group as essential monomer components. Disclosed is a pressure-sensitive adhesive composition for transparent plastics, which contains an acrylic polymer and an isocyanate crosslinking agent whose distribution is not 10 to 50, and is substantially free of a carboxyl group-containing monomer in the monomer component constituting the acrylic polymer. . Further, in the examination process of the patent, it is explained by the applicant of the patent that the molecular weight distribution of the acrylic polymer is about 4-9.

JP 2010-77287 A Patent No. 4531099

  The present invention relates to a laminate for a touch panel having a conductive film made of metal or metal oxide, for a conductive film that has excellent heat-resistant foaming resistance, moist heat resistance (whitening resistance), and does not corrode metal or metal oxide. It aims at providing the adhesive composition, the laminated body using this, and the touchscreen using this laminated body.

Furthermore, this invention aims at providing the adhesive composition for electrically conductive films which can form the coating film of sufficient thickness by one application | coating process.
In recent years, a display frame has been printed on a surface support constituting the surface of a touch panel. A pressure-sensitive adhesive is also used to bond the surface support on which the frame is printed and a transparent electrode or the like, but the polymers disclosed in Patent Documents 1 and 2 have a large weight average molecular weight, and particularly Since the polymer disclosed in Patent Document 2 has a narrow molecular weight distribution, the pressure-sensitive adhesive does not sufficiently follow the step of the printed portion, and a void is formed, which causes foaming.

  Then, this invention also aims at providing the laminated body for touchscreens using the adhesive which fully follows a printing level | step difference.

The pressure-sensitive adhesive composition for a conductive film of the present invention comprises (A) a (meth) acrylic polymer having a weight average molecular weight of 50,000 to 150,000 having a functional group other than an acidic group,
(B) including an isocyanate-based crosslinking agent,
In 100 parts by weight of the (meth) acrylic polymer (A),
(a-1) an alkoxyalkyl (meth) acrylate is copolymerized in an amount in the range of 50 to 99.8 parts by weight;
(a-2) a monomer having a hydroxyl group is copolymerized in an amount in the range of 0.1 to 10 parts by weight;
(a-3) the nitrogen-containing monomer is copolymerized in an amount in the range of 0.1 to 5 parts by weight;
(a-4) an alkyl (meth) acrylate is copolymerized in an amount in the range of 0 to 49.8 parts by weight;
The (A) (meth) acrylic monomer is characterized in that a crosslinked structure of (B) an isocyanate compound is densely formed.

  The pressure-sensitive adhesive composition for a conductive film of the present invention forms a coating solution in which (A) (meth) acrylic polymer and (B) isocyanate-based crosslinking agent are dispersed or dissolved in an organic solvent. The solid content in the coating solution is preferably in the range of 50 to 80% by weight.

The gel fraction of this adhesive composition for electrically conductive films of this invention exists in the range of 60 to 70 weight% normally.
It is preferable that this adhesive composition for electrically conductive films of this invention is an adhesive composition for electrically conductive films for sticking an ITO electrode layer etc. on the surface of a glass substrate.

  The dry thickness of the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition for a conductive film when sticking an ITO electrode to the surface of the glass substrate of the pressure-sensitive adhesive composition for a conductive film of the present invention is usually 10 to 1000 μm. Is in range.

The laminate of the present invention is a laminate in which a base material, an adhesive layer, and a conductive layer are laminated in this order,
The pressure-sensitive adhesive layer is
(A) a (meth) acrylic polymer having a weight average molecular weight of 50,000 to 150,000 having a functional group other than an acidic group;
(B) including an isocyanate-based crosslinking agent,
In 100 parts by weight of the (meth) acrylic polymer (A),
(a-1) an alkoxyalkyl (meth) acrylate is copolymerized in an amount in the range of 50 to 99.8 parts by weight;
(a-2) a monomer having a hydroxyl group is copolymerized in an amount in the range of 0.1 to 10 parts by weight;
(a-3) the nitrogen-containing monomer is copolymerized in an amount in the range of 0.1 to 5 parts by weight;
(a-4) an alkyl (meth) acrylate is copolymerized in an amount in the range of 0 to 49.8 parts by weight;
The (A) (meth) acrylic monomer is characterized in that a crosslinked structure of (B) an isocyanate compound is densely formed.

The gel fraction of the adhesive composition for electrically conductive films used for the laminated body of this invention exists in the range of 60 to 70 weight% normally.
In the laminated body of this invention, a base material is a glass base material normally, the thickness of this glass base material exists in the range of 25-2000 micrometers, and a conductive layer is an ITO electrode.

In the laminate of the present invention, the thickness of the pressure-sensitive adhesive layer is usually in the range of 10 to 1000 μm.
This laminate can be suitably used as a laminate for a capacitive touch panel.

  In the present invention, the alkoxyalkyl (meth) acrylate and / or the alkoxyalkylene glycol (meth) acrylate (a-1) is preferably methoxyethyl acrylate or methoxydiethylene glycol acrylate.

The touch panel of the present invention is a touch panel comprising a touch panel unit including a laminate in which a surface support, an adhesive layer, and a conductive layer are laminated in this order, and a flat panel display laminated on the touch panel unit.
The laminate is any one of the laminates described above.

In the present invention, the touch panel is preferably a capacitive touch panel.
In the touch panel of the present invention, frame printing is usually performed on the edge of the surface of the laminate that faces the pressure-sensitive adhesive layer of the surface support, and the thickness of this frame printing is usually 10 to 50 μm. It is in the range.

In the touch panel of the present invention, the conductive layer is usually a circuit pattern using ITO as a metal oxide, and the adhesive layer is in direct contact with the circuit pattern.
In the touch panel of the present invention, the thickness of the surface support is usually in the range of 25 to 2000 μm.

  In the touch panel of the present invention, usually, the conductive layer forms a circuit pattern, and the thickness of the circuit pattern is in the range of 10 to 100 nm.

  The pressure-sensitive adhesive layer in the laminate of the present invention is formed from a (meth) acrylic polymer having a functional group other than an acidic group and having a weight average molecular weight of 50,000 to 150,000. That is, since the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer of the present invention does not substantially contain an acid component, deterioration due to corrosion of wiring made of metal such as ITO or metal oxide can be effectively suppressed.

  Furthermore, the pressure-sensitive adhesive composition that forms the pressure-sensitive adhesive layer has a weight-average molecular weight (Mw) of the polymer that is the pressure-sensitive adhesive component is 50,000 to 150,000. Therefore, the crosslink density is increased and a hard pressure-sensitive adhesive layer is formed. Thus, since the pressure-sensitive adhesive layer is hard, it is possible to prevent moisture from entering from the outside.

  Furthermore, since the weight average molecular weight is small, the solid content concentration of the coating solution can be increased. For example, even a high concentration of about 70% by weight can be applied without any problem, and the coating film coating process is simplified. It has the advantage that it can be made.

  Furthermore, since the polymer has a low molecular weight and is crosslinked with a crosslinking agent at high density, the hardness of the pressure-sensitive adhesive composition for the conductive film becomes very high, and effectively prevents moisture from entering from the outside. Therefore, whitening of the pressure-sensitive adhesive layer is effectively suppressed.

  Therefore, in the adhesive composition for conductive film of the present invention, the laminate, and the touch panel using the same, corrosion of the transparent conductive film made of metal such as ITO or metal oxide hardly occurs, and the electrical characteristics of the transparent conductive film There is little fluctuation, and whitening and foaming hardly occur.

FIG. 1 is a cross-sectional view schematically showing an example of a touch panel unit in a resistive film type touch panel incorporating the laminate of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of a touch panel unit in a capacitive touch panel incorporating the laminate of the present invention. FIG. 3 is a cross-sectional view schematically showing an example of the configuration of the end portion of the capacitive touch panel. FIG. 4 is a cross-sectional view schematically showing the adhesive state of the adhesive sheet to the frame print portion formed at the end of the touch panel. FIG. 5 is a cross-sectional view for explaining the state of foaming generated in the laminate for a touch panel. FIG. 6 is a cross-sectional view for explaining the occurrence of a whitening phenomenon that occurs in a laminated body for a touch panel.

The laminate of the present invention is a laminate in which a base material, an adhesive layer, and a conductive layer are laminated in this order. Hereinafter, each constituent layer will be described.
〔Base material〕
The substrate generally functions as a surface support that constitutes the outermost surface of the touch panel, and is particularly limited as long as it has a function as such a surface support, that is, a certain strength and transparency. Not.

Examples of the material constituting the substrate include polycarbonate, polyethylene terephthalate, polymethyl methacrylate, and glass.
The substrate in the present invention may be a layer having a single layer structure, or may be a layer having a multilayer structure in which a plurality of layers are laminated and the characteristics of each layer are summarized.

(Adhesive layer)
The pressure-sensitive adhesive layer in the laminate of the present invention contains a specific (meth) acrylic polymer (A) and an isocyanate cross-linking agent (B) as described above, and a (meth) acrylic low molecular weight material and others as necessary. May be included. Hereinafter, each component will be described.

<(A) (Meth) acrylic polymer>
The (meth) acrylic polymer (A) includes an alkoxyalkyl (meth) acrylate and / or an alkoxyalkylene glycol (meth) acrylate (a-1), a hydroxyl group-containing monomer (a-2), a nitrogen-containing monomer ( a-3)
It is a copolymer obtained by copolymerizing an alkyl (meth) acrylate (a-4). Hereinafter, each constituent monomer will be described.

((A-1) alkoxyalkyl (meth) acrylate and / or alkoxyalkylene glycol (meth) acrylate)
If the alkoxyalkyl (meth) acrylate and the alkoxyalkylene glycol (meth) acrylate (a-1) are (meth) acrylates having an alkoxyalkyl group and / or an alkoxyalkylene glycol group as the alcohol-derived portion of the ester structure, There is no particular limitation. Since the alkoxyalkyl group and the alkoxyalkylene glycol group are excellent in hydrophilicity, even if water penetrates into the pressure-sensitive adhesive layer in the laminate of the present invention, it is dispersed and the hydrophilicity Water can be retained by an action such as hydrogen bonding, and water can be effectively suppressed from being precipitated and whitened in the pressure-sensitive adhesive layer.

  As such an alkoxyalkyl (meth) acrylate (a-1), from the viewpoint of suppressing whitening, the alkoxyalkyl having 1 to 2 carbon atoms in the alkoxy moiety and 1 to 4 carbon atoms in the alkyl moiety. An alkoxyalkylene glycol (meth) acrylate in which the (meth) acrylate and the alkoxy moiety have 1 to 2 carbon atoms and the alkylene glycol is ethylene glycol and / or propylene glycol is preferable, and the alkoxy moiety has 1 carbon atom. An alkoxyalkyl (meth) acrylate having 1 to 2 carbon atoms in the alkyl moiety and an alkoxyalkylene glycol (meth) acrylate in which the alkoxy moiety has 1 carbon atom and the alkylene glycol is ethylene glycol are more preferable.

  Examples of such alkoxyalkyl (meth) acrylate (a-1) include 2-methoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl acrylate, 3-methoxypropyl (meth) Examples include acrylate, 3-ethoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, and 4-ethoxybutyl (meth) acrylate.

  Examples of such alkoxyalkylene glycol (meth) acrylates include methoxydiethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, and ethoxytriethylene glycol (meth) acrylate.

Among these, 2-methoxyethyl acrylate and methoxydiethylene glycol acrylate are preferable from the viewpoint of suppressing whitening.
In the present invention, the alkoxyalkyl (meth) acrylate and the alkoxyalkylene glycol (meth) acrylate (a-1) may be used singly or in combination of two or more.

  Such a monomer forms 50 to 99.8% by weight, preferably 55 to 99.1% by weight in 100% by weight of the (meth) acrylic polymer (A) forming the pressure-sensitive adhesive layer in the laminate of the present invention. Copolymerized. If the copolymerization amount is less than 50% by weight, precipitation of moisture may not be suppressed at the time of wet heat, the pressure-sensitive adhesive layer may be whitened, and the appearance may be abnormal. On the other hand, when the copolymerization amount exceeds 99.8% by weight, the amount of the monomer having a functional group is inevitably reduced, and a sufficient crosslinked structure may not be formed.

((A-2) Monomer having a hydroxyl group)
The (meth) acrylic polymer (A) used in the pressure-sensitive adhesive layer constituting the laminate of the present invention is copolymerized with a hydroxyl group-containing monomer (a-2).

  When at least a part of the monomer (a-2) is crosslinked by the isocyanate-based crosslinking agent (B) described later, high cohesive force is achieved in the pressure-sensitive adhesive layer, and foaming is efficiently suppressed.

  As the monomer having a hydroxyl group, a monomer (a-2) is preferably a (meth) acrylic acid ester having a hydroxyl group. Examples of such compounds include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, Mention may be made of 6-hydroxyhexyl (meth) acrylate and 8-hydroxyoctyl (meth) acrylate.

  Examples of the (meth) acrylic acid ester having a hydroxyl group as described above include 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate from the viewpoint of reactivity with the isocyanate-based crosslinking agent (B). preferable.

The monomer (a-2) having a hydroxyl group described above may be used alone or in combination of two or more.
In 100% by weight of the (meth) acrylic polymer (A) used in the present invention, the monomer (a-2) is 0.1 to 10% by weight, preferably 0.8 to 9% by weight, more preferably 1. Copolymerized in an amount in the range of 2-6% by weight.

When the amount of the monomer (a-2) is less than the above range, the number of hydroxyl groups involved in crosslinking decreases, and a crosslinked structure by the isocyanate-based crosslinking agent (B) described later may not be sufficiently formed. On the other hand, when the copolymerization amount is more than 10% by weight, a crosslinked structure is excessively formed, and other characteristics such as step following ability may be insufficient.
((A-3) Nitrogen-containing monomer)
In the pressure-sensitive adhesive constituting the pressure-sensitive adhesive composition for a conductive film of the present invention, a nitrogen-containing monomer is copolymerized in the acrylic polymer (A).

Examples of nitrogen-containing monomers include amino group-containing monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate,
Amide group-containing monomers such as (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-hexyl (meth) acrylamide,
Nitrogen-containing heterocycle-containing monomers such as vinylpyrrolidone, acryloylmorpholine, vinylcaprolactam,
Cyano group-containing monomers such as cyano (meth) acrylate,
Examples include maleimide group-containing monomers such as maleimide monomers such as maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide and the like.

Such a nitrogen-containing monomer is copolymerized in an amount in the range of 0.1 to 5% by weight, preferably 0.1 to 4% by weight in 100% by weight of the (meth) acrylic polymer (A).
This nitrogen-containing monomer promotes the formation of a crosslinked structure between the polyisocyanate compound (B) as a crosslinking agent and the monomer (a-2) having a hydroxyl group, and further, the hydroxyl group in the (meth) acrylic polymer (A) It is a component that forms a pseudo-crosslinked structure by hydrogen bonding. If this nitrogen-containing monomer is less than the range specified above, the formation of a crosslinked structure becomes insufficient, and a hard pressure-sensitive adhesive layer cannot be formed. The water resistance of the agent layer is lowered, and whitening or the like easily occurs. Further, if a nitrogen-containing monomer is used in a large amount outside the above range, the pressure-sensitive adhesive becomes too hard, and the form followability at the frame printing portion may be lowered and durability may be insufficient.

((A-4) alkyl (meth) acrylate)
The pressure-sensitive adhesive constituting the conductive film pressure-sensitive adhesive composition of the present invention further comprises (a-4) alkyl (meth) acrylate in an amount within the range of 0 to 49.8 parts by weight, preferably 0 to 44.1. It may be copolymerized in an amount within the range of parts by weight. That is, the pressure-sensitive adhesive composition such as the conductive film of the present invention may or may not be copolymerized with a (meth) acrylic acid ester as described below. However, if the amount of these monomers to be copolymerized exceeds the above upper limit, the properties of the component (A) of the present invention are impaired, and the effects achieved by the present invention are not exhibited.

  Examples of (a-4) (meth) acrylic acid esters used here are methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n- Butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl ( Alkyl (meth) acrylates such as (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undeca (meth) acrylate, lauryl (meth) acrylate, oleyl (meth) acrylate, stearyl (meth) acrylate and dideca (meth) acrylate ) Acrylate, (meth) acrylonitrile; Rohekishiru (meth) acrylate, benzyl (meth) acrylate and phenyl (meth) acrylate.

(Other monomers)
Furthermore, other polymerizable compounds may be copolymerized in the (meth) acrylic polymer (A) used in the present invention within a range not impairing the properties of the pressure-sensitive adhesive of the present invention. Examples of such other polymerizable compounds include: vinyl acetate; alkyl styrene such as styrene, methyl styrene, dimethyl styrene, trimethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene and octyl styrene, fluorostyrene, Styrenic monomers such as chlorostyrene, bromostyrene, dibromostyrene, iodinated styrene, nitrostyrene, acetylstyrene, and methoxystyrene; glycidyl (meth) acrylate and the like may be used within a range that does not impair the effects of the present invention. it can. The other monomers described above can be used alone or in combination of two or more, but the allowable copolymerization amount is very small.

((A) (meth) acrylic polymer)
The (meth) acrylic polymer (A) used in the present invention can be obtained by copolymerizing the above-described monomers at the above ratio, but since no monomer having an acidic group is used, The coalescence is substantially free of acidic groups. Here, having substantially no acidic group means that a monomer having an acidic group is not added intentionally at the time of copolymerization, and it is usually 0.5 mgKOH / g in terms of the acid value of the resulting polymer. It is as follows.

  Examples of the monomer having an acidic group include (meth) acrylic acid, maleic acid, itaconic acid, a monomer having a phosphoric acid group, a monomer having a sulfuric acid group, and the like. These monomers are the pressure-sensitive adhesive of the present invention. It is not contained in the copolymer that forms.

  In the present invention, the (meth) acrylic polymer (A) is not copolymerized with the acidic group-containing monomer as described above. Since the acidic group-containing monomer is not copolymerized in this way, the (meth) acrylic polymer (A) used in the present invention corrodes even if it is in direct contact with the wiring made of metal or metal oxide. In other words, the pressure-sensitive adhesive layer in the laminate of the present invention can be provided with a characteristic that the resistance value of the wiring is not changed over a long period of time.

  Furthermore, the (meth) acrylic polymer (A) used in the present invention has a weight average molecular weight in the range of 50,000 to 150,000, preferably 80,000 to 150,000. In addition, in this specification, a weight average molecular weight is a weight average molecular weight of standard polystyrene conversion measured by GPC (gel permeation chromatography).

  Conventionally used pressure-sensitive adhesives have used a high molecular weight acrylic polymer having a weight average molecular weight of about 400,000 to 1.6 million, but in the present invention, as described above, 50,000 to 15 as a (meth) acrylic polymer. By using a polymer (A) having a remarkably low molecular weight compared to the conventionally used pressure-sensitive adhesive (400,000 to 1.6 million), the crosslink density is increased, and as a result, the cured pressure-sensitive adhesive is very hard. Become. However, until the pressure-sensitive adhesive is completely cured, the acrylic polymer has a low weight average molecular weight, so it exhibits good fluidity and very good form following, but after the crosslinked structure has completely progressed The pressure-sensitive adhesive layer becomes very hard, and moisture that penetrates from the end of the structure is not taken into the pressure-sensitive adhesive layer. Therefore, the pressure-sensitive adhesive layer of the present invention does not whiten and has very excellent water resistance.

  In the present invention, for the (meth) acrylic polymer (A), the glass transition temperature (Tg) determined by the Fox equation is usually in the range of -70 ° C to 0 ° C, preferably -70 ° C to -30 ° C. It is in. By using the (meth) acrylic polymer (A) having such a glass transition temperature (Tg), a pressure-sensitive adhesive layer having excellent adhesive strength at room temperature can be obtained.

(Method for producing (meth) acrylic polymer (A))
The (meth) acrylic polymer (A) can be produced by a known method, but is preferably produced by solution polymerization. In the solution polymerization, for example, ethyl acetate, methyl ethyl ketone, toluene, acetone or the like can be used as a polymerization solvent.

  Specifically, the polymerization solvent and raw material monomer are charged into the reaction vessel in the proportions described above, a polymerization initiator is added under an inert gas atmosphere such as nitrogen gas, and the reaction temperature is heated to about 50 to 90 ° C., React for 4-20 hours.

  Examples of the reaction initiator used for solution polymerization include azo initiators and peroxide initiators. These initiators are usually used in an amount in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the raw material monomer. Moreover, you may add suitably a polymerization initiator, a chain transfer agent, a raw material monomer, and a solvent suitably during the said polymerization reaction.

  Under the above-mentioned conditions, the weight average molecular weight of the (meth) acrylic polymer (A) to be obtained is determined by using a molecular weight regulator such as a normal alkyl mercaptan (eg, normal decyl mercaptan) and a solvent to be used according to a known technique. It can be adjusted by adjusting the reaction conditions such as the type and amount, the type and amount of the polymerization initiator, the reaction time, and the reaction temperature.

<(B) Isocyanate-based crosslinking agent>
The pressure-sensitive adhesive layer in the laminate of the present invention further contains an isocyanate-based crosslinking agent (B). The crosslinking agent (B) causes a crosslinking reaction with the crosslinking functional group derived from the monomer (a-2) in the (meth) acrylic polymer (A) to form a three-dimensional crosslinked structure, and an adhesive layer A high cohesive force is imparted to the surface. For example, a metal chelate-based crosslinking agent other than an isocyanate-based crosslinking agent has insufficient durability under a high-temperature environment and may not suppress foaming.

  Examples of the isocyanate-based crosslinking agent include two or more isocyanate groups in a molecule such as tolylene diisocyanate, xylylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenylmethane diisocyanate. A compound having: a compound obtained by addition reaction with a polyhydric alcohol such as trimethylolpropane or pentaerythritol, an isocyanurate compound, a burette type compound, and a known polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, poly Has two or more isocyanate groups in the urethane prepolymer type molecule that has undergone addition reaction with isoprene Mention may be made of the compound.

  Among these, xylylene diisocyanate and its trimethylolpropane adduct, and hexaxylene diisocyanate, and the hexamethylolpropane adduct can be improved in that the compatibility with the adherend can be improved, the entrainment of bubbles during bonding can be reduced, and the outgassing at high temperatures can be suppressed. An isocyanurate compound of methylene diisocyanate is preferred, and hexamethylene diisocyanate and its trimethylolpropane adduct are preferred from the viewpoint of improving the step following property of the affixed surface and improving the heat resistant foaming property.

The isocyanate-based crosslinking agent (B) described above can be used alone or in combination of two or more.
By blending the isocyanate-based cross-linking agent (B), the cohesive force of the pressure-sensitive adhesive layer in the laminate of the present invention is improved, and even when air bubbles are slightly involved at the time of pasting, the expansion of the air bubbles can be suppressed, Excellent heat-resistant foaming properties are exhibited.

<(Meth) acrylic low molecular weight product>
The pressure-sensitive adhesive layer in the laminate of the present invention has a nitrogen-containing (meta) from the viewpoint of improving the conformability to the base material and the adherend and improving the cohesive force due to the interaction with the (meth) acrylic polymer (A). ) You may contain the (meth) acrylic low molecular weight body which does not have an acidic group substantially formed by superposing | polymerizing the monomer containing an acrylic monomer. The meaning of “substantially no acidic group” is the same as in the (meth) acrylic polymer (A).

  Examples of the nitrogen-containing (meth) acrylic monomer include the nitrogen-containing monomers described above. Among these, the cohesive force of the pressure-sensitive adhesive is improved, and further, crosslinking with the isocyanate-based crosslinking agent (B) is promoted. From the viewpoint that it can be used, dimethylaminoethyl (meth) acrylate and acrylamide are preferable.

Of course, the (meth) acrylic low molecular weight substance may have a nitrogen-free (meth) acrylic monomer as a constituent monomer, and examples of such a monomer include methyl (meth) acrylate. , Ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meta ) Acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undeca (meth) acrylate and dideca (meth) ) Alkyl (meth) acrylates such as acrylate,
2-hydroxyethyl (meth) acrylate, 2-hydroxyethylpropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate And hydroxyalkyl (meth) acrylates such as 8-hydroxyoctyl (meth) acrylate.

Furthermore, a styrene monomer such as α-methylstyrene may be copolymerized.
Among these, it is preferable to use an alkyl (meth) acrylate in a proportion of 80 to 99% by weight from the viewpoint of polymerizability and compatibility with the (meth) acrylic polymer (A).

  The weight average molecular weight of the (meth) acrylic low molecular weight substance described above is 5,000 or more and less than 50,000. Such a (meth) acrylic low molecular weight product can be produced by various known methods.

Such (meth) acrylic low molecular weight substances can be used alone or in combination of two or more.
<Other ingredients>
In the pressure-sensitive adhesive layer in the laminate of the present invention, an antioxidant, a metal corrosion inhibitor, a light stabilizer, a tackifier, a plasticizer, as long as the effect of the pressure-sensitive adhesive layer in the laminate of the present invention is not impaired. An antistatic agent, a crosslinking accelerator, a reworking agent, and the like can also be blended.

Examples of the metal corrosion inhibitor include benzotriazole compounds, phenol compounds, and aromatic amine compounds.
The blending amount of these other components is appropriately adjusted within a range not impairing the effects of the present invention.

[Conductive layer]
The conductive layer in the laminate of the present invention may have a single layer structure made of metal or metal oxide, or may have a multilayer structure in which an electrode support or the like is further laminated on the layer. In the case of a multilayer structure, the pressure-sensitive adhesive layer in the laminate of the present invention is in contact with the electrode support.

  Examples of the metal or metal oxide include ITO (indium tin oxide), ATO (antimony tin oxide), and tin oxide. Since these are excellent in transparency, they are suitable as a transparent conductive film in a touch panel.

Furthermore, examples of the constituent material of the electrode support include highly transparent glass, polycarbonate, polymethyl methacrylate, and polyethylene terephthalate.
The conductive layer preferably has a single-layer structure made of metal or metal oxide, which is mainstream in capacitive touch panels.

[Method for producing laminate]
The laminate of the present invention is formed by laminating the base material, the pressure-sensitive adhesive layer, and the conductive layer described above in this order.

Although the manufacturing method of the said laminated body is not specifically limited, For example, (1) The adhesive composition which forms an adhesive layer is apply | coated on a base material, an adhesive layer is formed, and also a conductive layer on the adhesive layer. How to form,
(2) A method of forming a pressure-sensitive adhesive layer by applying a pressure-sensitive adhesive composition that forms a pressure-sensitive adhesive layer on a conductive layer, and further laminating a substrate on the pressure-sensitive adhesive layer,
(3) An adhesive layer is formed in advance on a release liner, this (adhesive layer) is transferred onto a substrate, the release liner is peeled off, and the transferred adhesive layer is transferred to an adhesive layer. A method of adhering to the conductive layer together with the base material so as to be in contact with the conductive layer,
(4) An adhesive layer is previously formed on the release liner, this (adhesive layer) is transferred onto the conductive layer, the release liner is peeled off, and the transferred adhesive layer is transferred to the adhesive layer. The method of sticking to a base material with a conductive layer so that it may touch a base material is mentioned.

  In the pressure-sensitive adhesive composition, the isocyanate-based crosslinking agent (B) is usually 0.1 to 10 parts per 100 parts by weight of the (meth) acrylic polymer (A) and the (meth) acrylic polymer (A). Part by weight, preferably 0.1 to 5 parts by weight, and can be obtained by blending other components as required.

  Further, when the pressure-sensitive adhesive composition is applied on a substrate or a conductive layer, or when a pressure-sensitive adhesive layer is formed on a release liner (eg, release-treated PET), a pressure-sensitive adhesive layer forming component is As with known pressure-sensitive adhesives, they are diluted to an appropriate concentration with a solvent, coated on a substrate or a release liner, and dried. Thereby, an adhesive layer is formed.

  In addition, although there is no restriction | limiting in particular in the said coating method, For example, it can apply | coat using a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, or a spray coater.

  The coating solution containing the (meth) acrylic polymer (A), the crosslinking agent (B), and other components used as needed in the present invention is a (meth) acrylic polymer (A). Since the weight average molecular weight (Mw) is low, the concentration of non-volatile components can be easily adjusted in a solvent such as ethyl acetate, methyl ethyl ketone, acetone, and toluene. Therefore, by using such a coating solution, the thickness of the pressure-sensitive adhesive layer after coating can be easily set to a desired thickness. In particular, the coating solution can easily increase the non-volatile content. For example, the non-volatile content can be adjusted within a range of 40 to 80%, preferably 50 to 75%, so that a desired thickness can be obtained. The (dry thickness) pressure-sensitive adhesive layer can be formed with a small number of coatings.

  Further, by using a solution having a high nonvolatile content as described above, the leveling property of the coating film after coating and drying is improved, and the drying time is shortened and the workability is improved. Furthermore, since the amount of volatile solvent is small, the burden on the environment is also reduced.

  Utilizing such properties, the pressure-sensitive adhesive layer in the laminate of the present invention has a thickness within the range of 10 to 1000 μm after drying the coating solution (dry thickness), preferably 25 to 25 μm. It is obtained by coating so as to have a thickness in the range of 500 μm.

  When this adhesive application solution is applied onto a release liner, it is applied onto the liner, and after removing the solvent, the surface of the formed adhesive layer (the surface not in contact with the release liner) Another release liner is stuck, and it is usually cured at a temperature of 0 to 50 ° C. for 1 to 10 days, and crosslinked with an isocyanate-based crosslinking agent (B).

Thereby, the gel fraction of the formed pressure-sensitive adhesive layer is usually in the range of 50 to 80%, preferably 50 to 70%. In the present invention, the gel fraction is determined as follows.
About 0.1 g of the adhesive layer sample after aging at 23 ° C for 7 days was collected in a sample bottle, added with 30 cc of ethyl acetate, shaken for 4 hours, and then filtered the contents of this sample bottle through a 200 mesh stainless steel wire mesh. Then, the residue on the wire mesh is dried at 100 ° C. for 2 hours, the dry weight is measured, and the following formula is obtained.

このようにして粘着剤層を用いて粘着シートを形成して使用することもできる。

Thus, an adhesive sheet can be formed and used using an adhesive layer.

[Touch panel]
The touch panel of the present invention is a touch panel comprising a touch panel unit including a laminate in which a surface support, an adhesive layer, and a conductive layer are laminated in this order, and a flat panel display laminated on the touch panel unit. The laminate is a laminate of the present invention. That is, the base material in the laminated body of the present invention functions as a surface support in the touch panel of the present invention.

As shown in FIGS. 1 and 2, the touch panel unit includes a resistive touch panel unit (see FIG. 1) and a capacitive touch panel unit (see FIG. 2).
FIG. 1 shows an example of a resistive film type touch panel unit 10-1. As shown in FIG. 1, in the resistive touch panel unit 10-1, the upper laminate 11-1 and the lower laminate 13-1 are separated so that the gap 34 is formed by the bonding agent 30. A spacer 32 is arranged in the gap 34 in order to secure an effective space.

  In the upper laminate 11-1, a transparent conductive film 27-1 made of metal or metal oxide is disposed facing the gap 34. The transparent conductive film 27-1 is formed of a conductive material having transparency such as ITO (indium tin oxide), ATO (antimony tin oxide), tin oxide, and usually, as shown in FIG. 1, polyethylene terephthalate ( PET) or an upper electrode support 25-1 made of glass.

  A surface support 21-1 is disposed on the outermost surface of the upper laminate 11-1, and this surface support 21-1 is usually a transparent film such as highly transparent glass or polycarbonate, polyethylene terephthalate (PET). It is.

In order to bond the surface support 21-1 and the upper electrode support 25-1, an adhesive layer 23-1 is formed. The upper laminated body 11-1 described above corresponds to the laminated body of the present invention.
Similarly, a transparent conductive film 27-2 made of metal or metal oxide is formed on the lower laminate 13-1 so as to face the gap 34. This transparent conductive film 27-2 is made of ITO (indium). Tin oxide), ATO (antimony tin oxide), tin oxide and other conductive materials having transparency, and usually a lower electrode support 25- made of polyethylene terephthalate (PET) or glass as shown in FIG. 2 is formed on the surface.

  A deep surface support 21-2 is formed at the deepest portion of the lower laminate 13-1 so as to face the surface of the flat panel display (FPD). The deep surface support 21-2 is made of glass or It is formed from a highly transparent member such as polycarbonate.

  In the lower laminate 13-1, an adhesive layer 23-2 is formed in order to bond the deep surface support 21-2 and the lower electrode support 25-2. The lower laminated body 13-1 described above also corresponds to the laminated body of the present invention.

Moreover, the adhesive which comprises the adhesive layer in the laminated body of this invention as the said bonding agent 30 may be used.
The transparent conductive films 27-1 and 27-2 are formed as a circuit pattern, and the pressure 34 is applied to the gap 34 by applying pressure from above the surface support 21-1. The transparent conductive films 27-1 and 27-2 are brought into contact with each other to be energized to detect the pressurized portion.

  In the resistive touch panel unit 10-1, the thickness of the surface support 21-1 is usually 25 to 2000 μm, and the thickness of the upper transparent conductive film 27-1 is usually 10 to 100 nm. The thickness of the body 25-1 is usually 25 to 2000 μm. As described above, the thickness of the pressure-sensitive adhesive layer 23-1 for laminating them is in the range of 10 to 1000 μm.

  Similarly, in the resistive film type touch panel unit, the thickness of the deep surface support 21-2 is usually 25 to 2000 μm, and the thickness of the lower transparent electrode film 27-2 is usually 10 to 100 nm. The thickness of the support 25-2 is usually 25 to 2000 μm. As described above, the thickness of the pressure-sensitive adhesive layer 23-2 on which these are laminated is in the range of 10 to 1000 μm.

Further, in the resistive film type touch panel unit 10-1, the width of the gap 34 formed at the center is usually in the range of 100 to 300 μm.
On the other hand, as shown in FIG. 2, the capacitive touch panel unit 10-2 generally includes an upper laminated body 15-1 and a lower part sandwiching a central support 60 made of a highly transparent member such as glass or polycarbonate. In many cases, the laminated body 15-2 has a structure in which the laminated body 15-2 is disposed to face the laminated body 15-2.

  In the upper laminate 15-1 of the capacitive touch panel 10-2, a transparent conductive film 57-1 is disposed in contact with the central support 60, and a cover glass or polyethylene terephthalate (PET) is disposed on the outermost surface. A surface support 51-1 made of a light transmissive member such as) is disposed. An adhesive layer 53-1 is disposed so as to adhere the transparent conductive film 57-1 and the surface support 51-1, and the adhesive layer 53-1 is in direct contact with the transparent conductive film 57-1. doing. The upper laminate 15-1 described above corresponds to the laminate of the present invention.

  On the other hand, in the lower laminate 15-2 in the capacitive touch panel unit 10-2, a transparent conductive film 57-2 is disposed in contact with the central support 60, and in the deepest part, a cover glass or polyethylene is provided. A surface support 51-2 made of a light transmissive member such as terephthalate (PET) is disposed. An adhesive layer 53-2 is disposed so as to bond the transparent conductive film 57-2 and the deepest surface support 51-2, and the adhesive layer 53-2 is formed of the transparent conductive film 57-2. In direct contact. The lower laminated body 15-2 described above also corresponds to the laminated body of the present invention.

In the capacitive touch panel unit 10-2, the deepest surface support 51-2 is disposed so as to face the flat panel display.
In the capacitive touch panel unit 10-2, the thickness of the upper surface support 51-1 is usually 25 to 2000 μm, and the thickness of the upper transparent conductive film 57-1 is usually 10 to 100 nm. The thickness of the pressure-sensitive adhesive layer 53-1 for adhering is 10 to 1000 μm as described above. In the lower laminate 15-2, the thickness of the lower transparent conductive film 57-2 is usually 10 to 100 nm, and the thickness of the deepest surface support 51-2 is usually 25 to 2000 μm. As described above, the thickness of the pressure-sensitive adhesive layer 53-2 for adhering is 10 to 1000 μm. In addition, the thickness of the central support 60 between the upper laminate 15-1 and the lower laminate 15-2 is usually in the range of 25 to 2000 μm.

  The upper transparent conductive film 57-1 and the lower transparent conductive film 57-2 form a circuit pattern. Further, in the capacitive touch panel unit 10-2 shown in FIG. 2, the upper laminate 15-1 and the lower laminate 15-2 are provided in two series independently provided in the X-axis direction and the Y-axis direction, respectively. By using this circuit, one of the upper laminate 15-1 or the lower laminate 15-2 can be omitted.

In the capacitive touch panel, the touch panel is driven by reading the change in the capacitance of the contact portion caused by the finger touching the surface of the touch panel unit 10-2.
For the touch panel unit as described above, for example, frame printing is performed on the surface of the edge of the upper surface support 51-1 shown by A in FIG. 2 that contacts the adhesive layer 53-1 of the surface support 51-1. Is done. This frame printing portion is shown in an enlarged manner in FIG. In FIG. 3, the frame printing portion is indicated by the number 62. The thickness (t ₀ ) of the frame printing portion 62 is normally 10 to 50 μm, and its cross section is formed in a substantially rectangular shape. As described above, the pressure-sensitive adhesive layer 53-1 is formed by transferring the pressure-sensitive adhesive layer previously formed on the release liner onto the conductive layer, peeling the release liner, and exposing the substrate (surface support) to the surface of the pressure-sensitive adhesive layer. Since the adhesive layer is hard and lacks shape followability, it is the end of the frame printing portion 62 and the surface as shown in FIG. A gap 64 is formed between the support 51-1 and the pressure-sensitive adhesive layer 53-1 that is not in contact with either the surface support 51-1 or the edge of the frame printing portion 62. Originally, as shown in FIG. 4 (b), the adhesive layer 53-1 must be in close contact with the edge portions of the surface support 51-1 and the frame printing portion 62 without forming the gap 64.

  However, in the case of a pressure-sensitive adhesive based on a pressure-sensitive adhesive component having a weight average molecular weight of 400,000 to 1.6 million and having a narrow molecular weight distribution as in the past, the shape of the pressure-sensitive adhesive layer is affected by such a very fine change in shape. Therefore, the gap 64 is formed without being completely changed.

  As described above, the pressure-sensitive adhesive layer 53-1 constituting the laminate of the present invention in which the surface support, the pressure-sensitive adhesive layer, and the conductive film (which may have a support) are laminated includes a specific monomer (a-1 ) Is used, and a (meth) acrylic polymer (A) having a weight average molecular weight (Mw) of 50,000 to 150,000 is used. Even in the imparted state, it has a very excellent form following ability, and no voids 64 are formed around the frame printing portion 62, and foaming is suppressed.

  When the touch panel of the present invention uses a member that easily generates outgas such as polycarbonate (PC) as the support 51-2 as shown in FIG. Outgassing from the body may occur, generating air bubbles 66 between the support and the adhesive layer. Even if a support that does not generate outgas is used, bubbles 68 may be involved when the support and the pressure-sensitive adhesive layer are bonded to each other, and if this bubble grows due to a temperature change, it will cause foaming. The pressure-sensitive adhesive layer in the touch panel of the present invention has a specific composition, and a cross-linked structure is formed at high density using a low molecular weight polymer having a weight average molecular weight (Mw) of 50,000 to 150,000. The agent layer can sufficiently follow the printing step of the support (from the microscopic viewpoint) and the frame printing, almost no bubble entrainment occurs, and the polymer (A) Since it is cross-linked with an isocyanate-based cross-linking agent (B), the pressure-sensitive adhesive layer has a very high cohesive force, and suppresses foaming due to outgassing and entrained bubble growth as described above with high cohesive force. Can do. Therefore, the foaming as described above can be hardly observed in the touch panel of the present invention.

  In the touch panel, when the touch panel is left under the durability test conditions (60 ° C., 90% RH), moisture may enter from the support and the end as shown in FIG. Under the condition where the temperature is high, the infiltrated moisture does not precipitate, but when the temperature is lowered, the infiltrated moisture is precipitated, the touch panel is whitened, and the haze is remarkably deteriorated (upper side in FIG. 6). As described above, the pressure-sensitive adhesive layer forming the touch panel of the present invention has a small polymer molecular weight and a densely crosslinked structure, and since the cured pressure-sensitive adhesive layer is very hard, moisture hardly enters, Deterioration of haze due to the whitening phenomenon is extremely difficult to occur (lower side in FIG. 6).

  Furthermore, since the pressure-sensitive adhesive layer in the touch panel of the present invention does not substantially contain an acidic group, even if the pressure-sensitive adhesive layer is in direct contact with a transparent conductive film made of metal or metal oxide, The change of the resistance value is 10% or less at the maximum, and this change amount is not a problem at all when driving the touch panel.

  As described above, the touch panel of the present invention comprises a (meth) acrylic polymer (A) having a specific composition as an adhesive layer and having a weight average molecular weight of 50,000 to less than 400,000 and a molecular weight distribution of 10 or more, and an isocyanate crosslinking agent. (B) is used to adhere a surface support (base material) and a conductive layer (eg, transparent conductive film), and the pressure-sensitive adhesive layer has excellent form following ability. It is possible to suppress the foaming by entrainment and the outgassing without the formation of voids in the frame printed part formed at the edge, and the influence of the alkoxy part of the alkoxyalkyl (meth) acrylate. Thus, the pressure-sensitive adhesive layer is hardly whitened and the haze is hardly lowered.

EXAMPLES Next, the present invention will be described in more detail with reference to examples of the present invention, but the present invention is not limited thereto.
The weight average molecular weight, gel fraction, non-volatile content, wet heat whitening property, heat-resistant foaming property, ITO corrosion property, coating property, workability, step following property, and adhesive strength were measured by the following methods.

〔Measuring method〕
<Molecular weight>
The molecular weight was determined by gel permeation chromatography (GPC) and the weight average molecular weight in terms of standard polystyrene under the following conditions.
GPC measurement conditions <br/> Measuring device HCL-8120GPC (manufactured by Tosoh Corporation)
GPC column configuration, the following five columns (all manufactured by Tosoh Corporation) were used.
(1) TSK-DEL HXL-H [guard column]
(2) TSK-DEL G7000HXL
(3) TSK-DEL GMHXL
(4) TSK-DEL GMHXL
(5) TSK-DEL G2500HXL
Dilute with tetrahydrofuran to a sample concentration of 1.0 mg / cm ³ Mobile phase solvent: Tetrahydrofuran Flow rate: 1.0 mg / cm ³
Column temperature: 40 ° C
<Gel fraction>
After aging at 23 ° C for 7 days, about 0.1 g of adhesive was collected in a sample bottle, 30 cc of ethyl acetate was added and shaken for 4 hours, and then the contents of this sample bottle were filtered through a 200 mesh stainless steel wire mesh. The residue on the wire mesh was dried at 100 ° C. for 2 hours, the dry weight was measured, and the gel fraction was determined by the following formula.
Gel fraction (%) = (Dry weight / Adhesive sampling weight) × 100
<Whitening (Haze)>
The release sheet on one side of the obtained pressure-sensitive adhesive sheet was peeled off and bonded to a polyethylene terephthalate film having a thickness of 38 μm and cut into a size of 50 mm × 50 mm.

Next, the other release film was peeled off and bonded to a glass plate having a thickness of 1.5 mm to prepare a test piece.
After measuring the haze before the durability test of the prepared test piece, it was left to stand in a 60 ° C. and 90% RH environment, and in a 85 ° C. and 85% RH environment, respectively. The test piece was taken out for 24 hours and allowed to stand at room temperature for 1 hour, and then the haze was measured to determine the difference from the haze value before the durability test.

The haze was measured using MH-150 (Murakami Color Research Laboratory Co., Ltd.).
<Foaming>
The release sheet on one side of the obtained pressure-sensitive adhesive sheet was peeled off, and bonded to a 38 μm thick polyethylene terephthalate film on which ITO was vapor-deposited to prepare a test piece.

Next, the other release film was peeled off and bonded to a glass plate having a thickness of 1.5 mm to prepare a test piece.
After the haze before the test of the prepared test piece was measured according to the above-described method, it was left in a dry environment at 60 ° C., 90% RH and 85 ° C., and then left in an environment at 85 ° C. and 85%. After 500 hours, the test piece was taken out, allowed to stand at room temperature for 1 hour, and then visually checked for foaming.
<Step following capability>
The obtained pressure-sensitive adhesive sheet (pressure-sensitive adhesive thickness: 50 μm) was peeled off from one side of the peeled PET film, and a 25 μm-thick PET film was bonded and cut into a 50 mm × 50 mm test piece.

Next, a 10 μm PET film cut to 25 mm × 25 mm is placed on a glass plate, the other peeled PET film of the prepared test piece is peeled off, and the PET film on the glass plate is pasted so as to cover the entire surface. The sample was allowed to stand for 500 hours and then left at room temperature for 1 hour, and the appearance of the step portion was observed.
<Coating property>
The obtained pressure-sensitive adhesive composition was coated on a polyethylene terephthalate film so that the thickness after drying was 250 μm. After coating, the appearance of the coating film was visually observed.

Evaluation content ○ ・ ・ The coating film surface is smooth and there is no appearance abnormality.
× · · Appearance abnormalities such as streaks and bubbles are observed on the coating surface
[Example 1]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 36 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C. in a nitrogen atmosphere. The reaction was carried out for 5 hours while adding 0.4 parts by weight of nitrile (AIBN) in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (1) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (1) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
[Example 2]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxydiethylene glycol acrylate (ECA), 36 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C. in a nitrogen atmosphere. During the reaction, azobisisobutyronitrile ( The reaction was carried out for 5 hours while adding 0.4 parts by weight of AIBN) in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (2) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (2) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals), and then dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 3
In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introduction pipe, 55 parts by weight of methoxyethyl acrylate (MEA), 36 parts by weight of butyl acrylate (BA), 2 parts by weight of dimethylaminoethyl acrylate (DMAEA), 7 parts by weight of 2-hydroxyethyl acrylate (2-HEA) and 50 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (3) having a solid content of 65% and an average molecular weight of 90,000.
Example 4
In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 36 parts by weight of butyl acrylate (BA), 2 parts by weight of n-vinylpyrrolidone (n-VP) Part, 7 parts by weight of 2-hydroxyethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (4) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (4) was mixed with an isocyanate-based curing agent (Takenate D-110N, manufactured by Mitsui Chemicals) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 5
A reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube was charged with 55 parts by weight of methoxyethyl acrylate (MEA), 36 parts by weight of butyl acrylate (BA), 2 parts by weight of acroylmorpholine (ACMO), 2 7 parts by weight of hydroxyethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (5) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (5) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals), and then dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 6
A reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube was charged with 91 parts by weight of methoxyethyl acrylate (MEA), 2 parts by weight of acrylamide (AM), 2 parts by weight of acroylmorpholine (ACMO), 2- 7 parts by weight of hydroxyethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (6) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (6) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals), and then dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 7
In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 37.5 parts by weight of butyl acrylate (BA), 0.5 part by weight of acrylamide (AM) Then, 7 parts by weight of 2-hydroxyethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (7) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (7) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals), and then dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 8
In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 34 parts by weight of butyl acrylate (BA), 4 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (8) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (8) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 9
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube, 55 parts by weight of methoxyethyl acrylate (MEA), 43 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 4-hydroxy 7 parts by weight of butyl acrylate (4-HBA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (9) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (9) was mixed with an isocyanate-based curing agent (Takenate D-110N, manufactured by Mitsui Chemicals), and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 10
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 41 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 2 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (10) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (10) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 11
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 33 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 10 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (11) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 1, the resulting acrylic polymer (11) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 12
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 36 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 81 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (12) having a solid content of 65% and an average molecular weight of 50,000.
As shown in Table 1, the resulting acrylic polymer (12) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals Co., Ltd.) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.
Example 13
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 36 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 82 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (13) having a solid content of 65% and an average molecular weight of 140,000.
As shown in Table 1, the resulting acrylic polymer (13) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

  Table 1 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thickness coating suitability of the obtained film.

〔比較例１〕
攪拌機、環流冷却器、温度計および窒素ガス導入管を備えた反応装置に、メトキシエチルアクリレート（MEA）３１重量部、ブチルアクリレート（BA）６０重量部、アクリルアミド（AM）２重量部、2-ヒドロキシエチルアクリレート（2-HEA）７重量部およびメチルエチルケトン（MEK)４５重量部を仕込み、窒素ガスを導入しながら７０℃に昇温した。

[Comparative Example 1]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube, 31 parts by weight of methoxyethyl acrylate (MEA), 60 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (14) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 2, the resulting acrylic polymer (14) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals, Inc.) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.
[Comparative Example 2]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube, 31 parts by weight of methoxyethyl acrylate (MEA), 31 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (15) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 2, the resulting acrylic polymer (14) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals, Inc.) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.
[Comparative Example 3]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introduction tube, 91 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 7 parts by weight of 2-hydroxyethyl acrylate (2-HEA) And 45 parts by weight of methyl ethyl ketone (MEK) was charged, and the temperature was raised to 82 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (16) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 2, the resulting acrylic polymer (16) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.
[Comparative Example 4]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 91 parts by weight of 2-ethylhexyl acrylate (2-EHA), 2 parts by weight of acrylamide (AM), 2-hydroxyethyl acrylate (2-HEA) 7 parts by weight and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (17) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 2, the resulting acrylic polymer (17) was mixed with an isocyanate-based curing agent (Takenate D-110N, manufactured by Mitsui Chemicals) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.
[Comparative Example 5]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 38 parts by weight of butyl acrylate (BA), 7-hydroxyethyl acrylate (2-HEA) 7 Part by weight and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (18) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 2, the resulting acrylic polymer (18) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals), and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.
[Comparative Example 6]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 32 parts by weight of butyl acrylate (BA), 6 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (19) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 2, the resulting acrylic polymer (19) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals Co., Ltd.), and then dried on the surface of the PET film subjected to the release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.
[Comparative Example 7]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 32 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA), 100 parts by weight of ethyl acetate (EtAc) and 20 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 89 ° C. while introducing nitrogen gas.

Subsequently, 0.2 parts by weight of azobisisobutyronitrile (AIBN) was added, and the reaction was carried out at 70 ° C. for 5 hours without adding normal dodecyl mercaptan NDM).
After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (20) having a solid content of 35% and an average molecular weight of 350,000.

  As shown in Table 2, the resulting acrylic polymer (20) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals), and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.
[Comparative Example 8]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 32 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA), 1 part by weight of acrylic acid (AA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 89 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C., and azobisisobutyronitrile (AIBN) 0 was added during the reaction. The reaction was carried out for 5 hours while adding 4 parts by weight in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (21) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 2, the resulting acrylic polymer (21) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals), and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.
[Comparative Example 9]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 65 parts by weight of methoxyethyl acrylate (MEA), 36 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA), 100 parts by weight of ethyl acetate (EtAc) and 20 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 89 ° C. while introducing nitrogen gas.

Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added and the reaction was carried out for 5 hours.
After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (22) having a solid content of 65% and an average molecular weight of 90,000.

  As shown in Table 2, the resulting acrylic polymer (22) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals) and dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.
[Comparative Example 10]
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, 55 parts by weight of methoxyethyl acrylate (MEA), 36 parts by weight of butyl acrylate (BA), 2 parts by weight of acrylamide (AM), 2-hydroxy 7 parts by weight of ethyl acrylate (2-HEA) and 45 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.005 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of normal dodecyl mercaptan (NDM) were added, and the reaction was started at 70 ° C. in a nitrogen atmosphere. The reaction was carried out for 5 hours while adding 0.4 parts by weight of nitrile (AIBN) in several portions.

After completion of the reaction, ethyl acetate (EtAc) was added to obtain an acrylic polymer (23) having a solid content of 65% and an average molecular weight of 90,000.
As shown in Table 2, the resulting acrylic polymer (23) was mixed with an isocyanate curing agent (Takenate D-110N, manufactured by Mitsui Chemicals), and then dried on the surface of the PET film that had been subjected to a release treatment. It apply | coated so that it might become thickness 250 micrometers, Furthermore, another peelable PET film was arrange | positioned on this application | coating surface, and it cured for 7 days.

  Table 2 shows the gel fraction, haze change, glass foam resistance, step following ability, ITO resistance change rate, and 250 μm thick coating suitability of the obtained film.

10-1 ... resistive film type touch panel unit 10-2 ... capacitive touch panel unit 11-1 ... upper laminate 13-1 ... lower laminate 15-1 ... upper part Laminate 15-2 ... Lower laminate 21-1 ... Surface support 21-2 ... Deep surface support 23-1 ... Adhesive layer 23-2 ... Adhesive layer 25 -1 ... Upper electrode support 25-2 ... Lower electrode support 27-1 ... Transparent conductive film 27-2 ... Transparent conductive film 30 ... Bonding agent 32 ... Spacer 34 ... Gap 51-1 ... Surface support 51-2 ... Surface support 53-1 ... Adhesive layer 53-2 ... Adhesive layer 57-1 ... Transparent conductive film 57 -2 ... transparent conductive film 60 ... central support 62 ... frame printing part 64 ... gap 66 ... bubble 68 ... bubble

Claims (18)

(A) a (meth) acrylic polymer having a weight average molecular weight of 50,000 to 150,000 having a functional group other than an acidic group;
(B) including an isocyanate-based crosslinking agent,
In 100 parts by weight of the (meth) acrylic polymer (A),
(a-1) an alkoxyalkyl (meth) acrylate and / or an alkoxyalkylene glycol (meth) acrylate is copolymerized in an amount in the range of 50 to 99.8 parts by weight,
(a-2) a monomer having a hydroxyl group is copolymerized in an amount in the range of 0.1 to 10 parts by weight;
(a-3) the nitrogen-containing monomer is copolymerized in an amount in the range of 0.1 to 5 parts by weight;
(a-4) an alkyl (meth) acrylate is copolymerized in an amount in the range of 0 to 49.8 parts by weight;
When the (A) (meth) crosslinked structure by Akuru based polymer (B) an isocyanate crosslinking agent is Ru is formed, a conductive film for a pressure-sensitive adhesive composition gel fraction is characterized in that a 50-80% .   The pressure-sensitive adhesive composition for a conductive film forms a coating liquid in which (A) (meth) acrylic polymer and (B) isocyanate-based crosslinking agent are dispersed or dissolved in an organic solvent, 2. The pressure-sensitive adhesive composition for a conductive film according to claim 1, wherein the solid content is in the range of 40 to 80 wt%.   The pressure-sensitive adhesive composition for conductive film according to claim 1, wherein the pressure-sensitive adhesive composition for conductive film has a gel fraction in the range of 60 to 70% by weight.   The conductive film according to claim 1, wherein the conductive film pressure-sensitive adhesive composition is a conductive film pressure-sensitive adhesive composition for adhering an ITO electrode to the surface of a glass substrate having a thickness of 25 to 2000 µm. Film adhesive composition. It is applied so that the dry thickness of the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition for a conductive film when sticking an ITO electrode to the surface of the glass substrate is in the range of 10 to 1000 μm. The adhesive composition for electrically conductive films of Claim 4 . A laminate in which a base material, an adhesive layer, and a conductive layer are laminated in this order,
The pressure-sensitive adhesive layer is
(A) a (meth) acrylic polymer having a weight average molecular weight of 50,000 to 150,000 having a functional group other than an acidic group;
(B) including an isocyanate-based crosslinking agent,
In 100 parts by weight of the (meth) acrylic polymer (A),
(a-1) an alkoxyalkyl (meth) acrylate and / or an alkoxyalkylene glycol (meth) acrylate is copolymerized in an amount in the range of 50 to 99.8 parts by weight,
(a-2) a monomer having a hydroxyl group is copolymerized in an amount in the range of 0.1 to 10 parts by weight;
(a-3) the nitrogen-containing monomer is copolymerized in an amount in the range of 0.1 to 5 parts by weight;
(a-4) an alkyl (meth) acrylate is copolymerized in an amount in the range of 0 to 49.8 parts by weight;
The pressure-sensitive adhesive layer is a laminate in which the (A) (meth) acrylic polymer has a crosslinked structure formed by (B) an isocyanate- based crosslinking agent , and has a gel fraction of 50 to 80% . The laminate according to claim 6, wherein the pressure-sensitive adhesive layer has a gel fraction in the range of 60 to 70% by weight.   The laminate according to claim 6, wherein the substrate is a glass substrate, the thickness of the glass substrate is in the range of 25 to 2000 μm, and the conductive layer is an ITO electrode. The laminate according to claim 6, wherein the pressure-sensitive adhesive layer has a dry thickness in the range of 10 to 1000 µm.   The laminate according to claim 6, wherein the laminate is a laminate for a capacitive touch panel.   7. The alkoxyalkyl (meth) acrylate and / or the alkoxyalkylene glycol (meth) acrylate (a-1) is at least one selected from methoxyethyl acrylate and methoxydiethylene glycol acrylate. Laminated body. In a touch panel comprising a touch panel unit including a laminate in which a surface support, an adhesive layer, and a conductive layer are laminated in this order, and a flat panel display laminated on the touch panel unit,
The touch panel, wherein the laminate is a laminate according to any one of claims 6 to 11.   The touch panel according to claim 12, wherein the touch panel is a capacitive touch panel.   The touch panel according to claim 12, wherein in the laminate, frame printing is performed on an edge of a surface of the surface support that faces the pressure-sensitive adhesive layer.   The touch panel according to claim 14, wherein a thickness of the frame printing is in a range of 10 to 50 µm.   The conductive layer is a circuit pattern using ITO as a metal oxide, and the pressure-sensitive adhesive layer is in direct contact with the circuit pattern. The touch panel described.   The thickness of the said surface support body exists in the range of 25-2000 micrometers, The touchscreen in any one of the Claims 12-16 characterized by the above-mentioned.   The touch panel according to claim 12, wherein the conductive layer forms a circuit pattern, and the thickness of the circuit pattern is in a range of 10 to 100 nm.

Images