JP5757809B2 - Laminated body and touch panel having the laminated body - Google Patents

Description

  The present invention relates to a laminate for a touch panel forming member having a specific pressure-sensitive adhesive layer, and a touch panel having the laminate.

  The touch panels currently used in the mainstream are roughly classified into a resistive touch panel and a capacitive touch panel, both of which are laminates of various materials, and are mainly made of acrylic adhesive for bonding. Is used.

  Since the touch panel is placed in a high-temperature and high-humidity environment in a durability test or an acceleration test, high transparency is required, and further, characteristics such as high heat resistance and wet heat resistance are required. In addition, the touch panel is a laminate of various materials as described above, and is disposed on the outermost surface of the touch panel device, so that whitening may occur due to penetration of moisture from the outside into each layer. When each layer constituting the body is stuck, foaming by entraining air, foaming by outgas generated from the material to be laminated, and the like become problems.

  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 (IMF).

  However, as a characteristic on materials such as PC, there is a characteristic that outgas derived from the material is generated under high temperature conditions, and in wet heat conditions, moisture flows from a film such as PC and adheres due to precipitation as fine water droplets. There is also a problem that it is difficult to suppress the whitening phenomenon of the agent layer. Furthermore, since the IMF has a step on the order of submicron, there is also a problem that the adhesive cannot follow the step and bubbles are involved.

  Conventionally, the above problems have been solved by blending an acid component such as acrylic acid as a constituent monomer of the polymer into the polymer constituting the pressure-sensitive adhesive and increasing the molecular weight. 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 whitening of the pressure-sensitive adhesive layer was prevented, and the acid component formed hydrogen bonds, and the high cohesive force caused by increasing the polymer molecular weight suppressed the generation of bubbles at high temperatures.

  By the way, recently, with the enhancement of functions such as multi-touch, capacitive touch panels are becoming mainstream in place of resistive touch panels. In this capacitive touch panel, the characteristics required for the resistive touch panel are naturally necessary, but in addition, because the adhesive directly contacts the conductive layer forming the circuit, The property that the adhesive does not affect 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), antimony tin oxide (ATO), or silver. Corrosion occurs due to contact with acid, and its resistance value increases. Therefore, it is not possible to use a means for securing characteristics such as heat resistance and heat-and-moisture resistance using a conventionally used acid component.

  Regarding the corrosion of the transparent electrode made of a metal or metal oxide such as ITO or silver, Patent Document 1 (Japanese Patent Laid-Open No. 2010-77287) discloses a pressure-sensitive adhesive containing a polymer mainly composed of an alkoxyalkyl acrylate. An agent layer is disclosed, and in 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 an alkoxyalkyl acrylate polymer having a weight average molecular weight of 400,000 to 1.6 million without using a carboxyl group-containing monomer, the corrosion of transparent electrodes made of metals such as ITO or metal oxides is improved. However, sufficient effects have not been obtained with respect to performance such as heat-and-moisture whitening resistance and heat-resistant foaming resistance. In addition, after manufacturing the laminated body constituting the touch panel, they are cut into a desired size and shape. However, in the touch panel using the polymer, workability in this cutting (adhesive is cut). It ’s not enough if you do n’t stick to it.

  Further, Patent Document 1 includes a member having a step such as a printing step (a step in a certain layer in a laminated body constituting the touch panel, which is formed by printing as a frame of a screen) in a touch panel or the like. It is mentioned that a touch panel or the like having a member provided with a frame-like printed portion is used in a mobile phone or the like. Patent Document 1 describes that the pressure-sensitive adhesive in the invention described in the document has a high performance (step difference followability) for filling the printing step, and is excellent in adhesive strength and durability at high temperatures. There is.

  However, the weight average molecular weight of the polymer disclosed in Patent Document 1 is 400,000 to 1.6 million (the weight average molecular weight of the polymers actually synthesized in the examples is 1 million, and the minimum is 600,000. When the amount of the solid content is increased when the coating solution is prepared by dissolving this in a solvent, the viscosity of the polymer solution becomes too high. In touch panel applications, particularly capacitive touch panels, it is necessary to form a thick adhesive layer to bond the surface support and a conductive film such as ITO, but the weight average molecular weight is 400,000 to Since 1.6 million alkoxyalkyl acrylate polymers cannot be used to prepare a coating solution with a high solid content, it is necessary to prepare a coating solution with a low solid content and apply it repeatedly. It is difficult to form a pressure-sensitive adhesive layer having a thickness required for the work (thick film coatability is insufficient). Further, such a high viscosity and high molecular weight polymer has insufficient step following ability.

  Patent Document 2 (Japanese Patent Laid-Open No. 2009-79203) also discloses an alkoxyalkyl acrylate polymer having a weight average molecular weight of 400,000 to 1,600,000 (in the examples, more than 1,000,000 and the lowest is 600,000). In the same manner as in Patent Document 1, it can not be said that such properties as moisture heat whitening resistance, heat resistant foaming resistance, cutting workability and step following ability are sufficient.

JP 2010-77287 A JP 2009-79203 A

  The present invention relates to a laminate for a touch panel having a conductive film made of a metal or a metal oxide, and the pressure-sensitive adhesive layer constituting the laminate has heat resistance (foaming resistance), moist heat resistance (moisture heat whitening resistance). For the purpose of providing a laminated body excellent in thick film coating property, cutting workability and step following property, and a touch panel using the same. Yes.

The laminate of the present invention is a laminate in which a substrate, an adhesive layer, and a conductive layer are laminated in this order, and the adhesive layer is
(A) It is obtained by copolymerizing a monomer containing 0.1 to 10% by weight of a (meth) acrylic monomer having a crosslinkable functional group and 0.1 to 30% by weight of a macromer (with all monomers being 100% by weight). A (meth) acrylic polymer having a weight average molecular weight of substantially 50,000 to less than 400,000
(B) a crosslinking agent,
The macromer has a polymerizable unsaturated group, a glass transition temperature of 50 to 180 ° C., a weight average molecular weight of Ri 500 to 100,000 der, the crosslinkable functional group is a hydroxyl group, the crosslinking agent is an isocyanate It is characterized by being a crosslinking agent .

  The monomer constituting the macromer is preferably a methacrylic monomer or a styrene monomer, and the pressure-sensitive adhesive layer is a (meth) acrylic low polymer formed by polymerizing a monomer containing a nitrogen-containing (meth) acrylic monomer. It preferably contains a molecular weight body.

Before SL (meth) acrylic polymer (A) preferably contains a nitrogen-containing monomer as its constituent monomers, wherein said macromer (meth) of the acrylic low molecular weight substances, at least one common constituent monomer It is preferable to have.

The conductive layer is a transparent conductive film usually made of metal or metal oxide, and the thickness of the pressure-sensitive adhesive layer is usually 10 to 1000 μm.
The touch panel of the present invention comprises 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 body is a laminate of the present invention. The touch panel is preferably a capacitive touch panel.

In the laminate, frame printing is usually performed on the edge of the surface of the surface support that faces the pressure-sensitive adhesive layer, and the thickness of the frame printing is usually in the range of 10 to 50 μm.
Furthermore, 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, and the thickness of the circuit pattern is usually within a range of 10 to 100 nm. In addition, the thickness of the surface support is usually in the range of 25 to 2000 μm.

  Since the pressure-sensitive adhesive layer in the laminate of the present invention does not substantially contain an acid component, it is possible to effectively suppress deterioration due to corrosion of a wiring made of a metal or metal oxide such as ITO, ATO, or silver.

  Furthermore, since the (meth) acrylic polymer (A) constituting the pressure-sensitive adhesive layer has a weight average molecular weight (Mw) of 50,000 or more and less than 40, the solid content can be kept at a high concentration in the solvent. When forming the pressure-sensitive adhesive layer, a sufficient thickness can be applied in a single coating process, and the pressure-sensitive adhesive layer is excellent in step followability and cutting workability.

And since a crosslinked structure is formed with a crosslinking agent, the adhesive layer in the laminated body of this invention is excellent also in heat resistance and wet heat-resistant stability.
Therefore, the pressure-sensitive adhesive layer in the laminate of the present invention hardly corrodes a transparent conductive film made of a metal such as ITO or ATO or a metal oxide, and also hardly whitens or foams.

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 frame printing at the end of the capacitive touch panel. FIG. 4 is a cross-sectional view schematically showing the adhesive state of the adhesive layer 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.

Next, the laminate and the touch panel of the present invention will be specifically described.
[Laminate]
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, triacetyl cellulose, cycloolefin polymer, 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)
As described above, the pressure-sensitive adhesive layer in the laminate of the present invention contains a specific (meth) acrylic polymer (A) and a crosslinking agent (B). Hereinafter, each component will be described.

<(A) (Meth) acrylic polymer>
The (meth) acrylic polymer (A) is a copolymer obtained by copolymerizing a (meth) acrylic monomer having a crosslinkable functional group, a macromer, and optionally other monomers. Hereinafter, each constituent monomer will be described.

((Meth) acrylic monomer having a crosslinkable functional group)
The crosslinkable functional group in the (meth) acrylic monomer is a functional group capable of causing a crosslinking reaction with the crosslinking agent (B), which is a group other than an acidic group, and has a cohesive force after crosslinking. From the viewpoint of improvement, a hydroxyl group is particularly preferable.

  Examples of (meth) acrylic monomers containing a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxyethylpropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 4-hydro Mention may be made of hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate and 8-hydroxyoctyl (meth) acrylate.

Among these, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl acrylate are preferable from the viewpoint of easy polymerization and crosslinkability.
The (meth) acrylic monomer having a crosslinkable functional group described above can be used alone or in combination of two or more.

  The (meth) acrylic monomer having such a crosslinkable functional group is copolymerized in an amount of 0.1 to 10% by weight with respect to all monomers used for the polymerization of the (meth) acrylic polymer (A). Preferably, it is copolymerized in an amount of 0.8 to 9% by weight, more preferably 1.2 to 6% by weight from the viewpoint of reactivity with the crosslinking agent and easy adjustment of the cohesive force of the pressure-sensitive adhesive layer. More preferably. This copolymerization ratio is achieved by adjusting the monomer charge ratio to this ratio in the production of the (meth) acrylic polymer (A).

(Macromer)
The macromer is a polymer having a polymerizable unsaturated group and having a weight average molecular weight of 500 to 100,000.

Examples of the polymerizable unsaturated group include an ethylenically unsaturated double bond.
The polymerizable unsaturated group of the macromer causes a radical polymerization reaction with the monomer constituting the (meth) acrylic polymer (A) and is taken into the (meth) acrylic polymer (A). And when it sees as a (meth) acrylic-type polymer (A), the side chain based on a macromer will be formed.

  By this side chain, the molecules of the (meth) acrylic polymer (A) are prevented from being densely packed together, whereby the pressure-sensitive adhesive layer in the laminate of the present invention has a flexible structure. Are better.

  And this macromer itself contains the (meth) acrylic polymer (A) in which the glass transition temperature calculated | required by the formula of Fox exists in the high temperature of 50-180 degreeC, Preferably it is 80-150 degreeC, and this was taken in. The pressure-sensitive adhesive layer is also excellent in heat-resistant foaming property.

  The weight average molecular weight of the macromer is 500 to 100,000, preferably 1000 to 50,000, from the viewpoint of step following ability. In the present specification, the weight average molecular weight is a weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography (GPC), and the same applies hereinafter.

  Examples of monomers in the polymer chain (main chain) part constituting the macromer include methacrylic monomers such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate and t-butyl methacrylate, styrene and α-methyl. Examples thereof include styrene monomers such as styrene, acrylonitrile, and the like. From the viewpoint of the cohesive strength of the pressure-sensitive adhesive layer in the laminate of the present invention, and the compatibility between the low molecular weight substance and the (meth) acrylic polymer (A) when an acrylic low molecular weight substance described later is added. Among them, methyl methacrylate, t-butyl methacrylate and styrene are preferable.

The production of the macromer described above can be carried out according to various known methods.
For example, (1) A method in which a polymer chain (living polymer anion) constituting a macromer is produced by living anion polymerization and methacrylic acid chloride or the like is allowed to act on the polymer chain;
(2) A method in which a radical polymerizable monomer such as methyl methacrylate is polymerized in the presence of a chain transfer agent such as mercaptoacetic acid to obtain an oligomer having a carboxyl group at the terminal, and then this is reacted with glycidyl methacrylate or the like. ;
(3) A method of polymerizing a radical polymerizable monomer such as methyl methacrylate in the presence of an azo polymerization initiator containing a carboxyl group to obtain an oligomer having a carboxyl group at the terminal, and then macromerizing with glycidyl methacrylate, etc. The method is mentioned.

  Macromers are also commercially available. For example, macromers having a methacryloyl group at the end and a main chain constituent monomer of methyl methacrylate (MMA) (product names: 45% AA-6 (AA-6S), AA-6 A macromer (product name: AS-6S, AS-6; manufactured by Toagosei Co., Ltd.) and a main chain is a styrene / acrylonitrile copolymer (manufactured by Toagosei Co., Ltd.). Product name: AN-6S; manufactured by Toagosei Co., Ltd.), and macromer (product name: AB-6; manufactured by Toagosei Co., Ltd.) whose main chain constituent monomer is butyl acrylate.

  The macromer described above is copolymerized in an amount of 0.1 to 30% by weight with respect to all monomers used for the polymerization of the (meth) acrylic polymer (A), and from the viewpoint of cohesion and compatibility. The copolymerization is preferably carried out in an amount of 0.1 to 25% by weight, more preferably 0.1 to 20% by weight. This copolymerization ratio is achieved by adjusting the charging ratio of the macromer to this ratio in the production of the (meth) acrylic polymer (A). Macromers may be used alone or in combination of two or more.

(Other monomers)
The (meth) acrylic polymer (A) may be copolymerized with a monomer other than the (meth) acrylic monomer having a crosslinkable functional group described above and a macromer.

Examples of other monomers 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 (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl ( Alkyl (meth) acrylates such as (meth) acrylate, undeca (meth) acrylate and dideca (meth) acrylate,
Methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, ethoxypropyl (meth) acrylate, ethoxy Examples include alkoxy (meth) acrylates and alkoxyalkylene (meth) acrylates such as butyl (meth) acrylate, methoxydiethylene glycol acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate and ethoxytriethylene glycol (meth) acrylate. be able to.

  These alkyl (meth) acrylates, alkoxy (meth) acrylates and alkoxyalkylene (meth) acrylates are preferably 60 to 99.8% by weight, preferably based on the total monomers used for the polymerization of the (meth) acrylic polymer (A). Is preferably used in a proportion of 66 to 99.0% by weight, more preferably 74 to 98.6% by weight. Furthermore, the total of alkoxy (meth) acrylate and alkoxyalkylene (meth) acrylate in the monomer is The use of 20% by weight or more is preferable in order to further suppress whitening due to moisture in the pressure-sensitive adhesive layer.

Furthermore, it is also preferable to contain a nitrogen-containing monomer as another monomer. As nitrogen-containing monomers, amino group-containing monomers such as dimethylaminoethyl (meth) acrylate, 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,
A cyano group-containing monomer such as cyano (meth) acrylate can be mentioned, and such a nitrogen-containing monomer is 5% by weight or less based on the total amount of monomers used for the polymerization of the (meth) acrylic polymer (A). Furthermore, the cohesive strength of the pressure-sensitive adhesive can be improved by copolymerization in the range of 0.1 to 4% by weight, and further, crosslinking with an isocyanate-based crosslinking agent can be promoted. This copolymerization ratio is achieved by adjusting the monomer charge ratio to this ratio in the production of the (meth) acrylic polymer (A).

  Other monomers that can be used in the present invention include vinyl acetate; (meth) acrylonitrile; cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate; styrene, α-methylstyrene, dimethylstyrene, trimethylstyrene, Styrenic monomers such as propyl styrene, butyl styrene, hexyl styrene, alkyl styrene such as heptyl styrene and octyl styrene, fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodinated styrene, nitrostyrene, acetylstyrene and methoxystyrene The body etc. are mentioned, These can be used in 0-10 weight% with respect to all the monomers used for superposition | polymerization of (meth) acrylic-type polymer (A). This copolymerization ratio is achieved by adjusting the monomer charge ratio to this ratio in the production of the (meth) acrylic polymer (A).

((A) (meth) acrylic polymer)
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, a polymerization solvent and a monomer are charged in the reaction vessel in the weight ratio 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 monomer. Moreover, you may add suitably a polymerization initiator, a chain transfer agent, a monomer, a solvent, etc. during the said polymerization reaction.

  Under the above conditions, the weight average molecular weight of the (meth) acrylic polymer (A) to be obtained is determined according to known techniques, such as the type and amount of the solvent used, the type and amount of the polymerization initiator, the reaction time, the reaction temperature, etc. It can be adjusted by adjusting the reaction conditions.

  For example, since the (meth) acrylic polymer (A) thus obtained does not use a monomer having an acidic group as a polymerization monomer, it has substantially no acidic group. Here, “having substantially no acidic group” means that the acidic group is not blended artificially, and it is usually 0.5 mgKOH / g or less in terms of acid value.

  Examples of the monomer having an acidic group include a monomer having a carboxyl group such as (meth) acrylic acid, maleic acid, and itaconic acid, a monomer having a phosphoric acid group, and a monomer having a sulfuric acid group. In the present invention, the (meth) acrylic polymer (A) is not copolymerized with the above acidic group-containing monomer. Since the acid group-containing monomer is not copolymerized in this way, the (meth) acrylic polymer (A) does not corrode even if it is in direct contact with a circuit made of metal or metal oxide. The pressure-sensitive adhesive layer in the laminate of the invention can be given a characteristic that the resistance value of the circuit is not changed over a long period of time.

Furthermore, the (meth) acrylic polymer (A) has a weight average molecular weight of 50,000 or more and less than 400,000, preferably 100,000 to 380,000.
In the conventional adhesive, a high molecular weight acrylic polymer having a weight average molecular weight of about 400,000 to 1,600,000 was used. In the present invention, as described above, the (meth) acrylic polymer has a relatively high molecular weight. By using a low one, the pressure-sensitive adhesive layer becomes soft and the step following property is good, and further, it becomes difficult to entrain bubbles in the production of a laminate having this pressure-sensitive adhesive layer.

  Even if a (meth) acrylic polymer having a weight average molecular weight of less than 50,000 is used, sufficient cohesive force described later cannot be obtained. On the other hand, (meth) acrylic polymers having a weight average molecular weight of 400,000 or more have poor step following ability and cause poor appearance. Moreover, in order to increase viscosity, it is inferior to the proper thickness coating.

  The (meth) acrylic polymer (A) described above may be used alone or in combination of two or more. The glass transition temperature (Tg) determined by the Fox formula of the polymer is usually -70 ° C. ˜0 ° C., preferably in the range of −70 ° C. to −30 ° C. 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.

<(B) Crosslinking agent>
The adhesive layer which comprises the laminated body of this invention contains the crosslinking agent (B).
This crosslinking agent (B) is crosslinked with the crosslinkable functional group of the (meth) acrylic polymer (A) to form a polymer, thereby giving a high cohesive force to the pressure-sensitive adhesive layer of the present invention. Sex is achieved. Specifically, the gel fraction of the pressure-sensitive adhesive layer in the laminate of the present invention is usually 50 to 80%, preferably 60 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.

前記架橋剤（Ｂ）としては、（メタ）アクリル系ポリマー（Ａ）における架橋性官能基と架橋することができる限り特に制限されないが、イソシアネート架橋剤が好ましい。

The crosslinking agent (B) is not particularly limited as long as it can be crosslinked with the crosslinkable functional group in the (meth) acrylic polymer (A), but an isocyanate crosslinking agent is preferable.

  Examples of the isocyanate crosslinking agent include compounds having two or more isocyanate groups in the molecule such as tolylene diisocyanate, xylylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate: Addition reaction with polyhydric alcohols such as trimethylolpropane and pentaerythritol, isocyanurate compounds, burette compounds, and addition with known polyether polyols, polyester polyols, acrylic polyols, polybutadiene polyols, polyisoprenes, etc. It has two or more isocyanate groups in the urethane prepolymer type molecule obtained by the reaction. Mention may be made of the compound.

  Among these, the adherence to the adherend of the pressure-sensitive adhesive layer, that is, the compatibility with the base material and the conductive layer such as glass, polycarbonate, polymethyl methacrylate and the like, and the entrainment of bubbles at the time of bonding can be reduced. Xylylene diisocyanate and its trimethylolpropane adduct are preferable in that the outgassing at the surface can be suppressed, and hexamethylene diisocyanate and the heat resistant foaming property can be improved by improving the step following property of the attachment surface. The trimethylolpropane adduct and isocyanurate compounds are preferred.

  Such a crosslinking agent (B) may be used alone or in combination of two or more, and is usually 0.1 to 5 parts by weight, preferably 100 parts by weight of (meth) acrylic polymer (A), preferably 0.1 to 2 parts by weight are included.

<(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). ) It is preferable to contain a (meth) acrylic low molecular weight substance substantially free from an acidic group, which is obtained by polymerizing a monomer containing an acrylic monomer.

  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 can be improved, and further, crosslinking with an isocyanate-based crosslinking agent can be promoted. From the viewpoint, dimethylaminoethyl (meth) acrylate and acrylamide are preferred.

  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, dideca (meth) ) Acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxy ester Tylpropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate and 8-hydroxyoctyl (meth) acrylate, styrenic and α-methylstyrene may be mentioned. Among these, from the viewpoint of polymerizability and compatibility with the (meth) acrylic polymer (A), the alkyl (meth) acrylate is in a proportion of 80 to 99% by weight with respect to the (meth) acrylic low molecular weight product. It is preferable to use it.

  Further, from the viewpoint of compatibility with the (meth) acrylic polymer (A), it is more preferable that the (meth) acrylic low molecular weight substance and the macromer have at least one common constituent monomer.

  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 a (meth) acrylic low molecular weight substance may be used alone or in combination of two or more, and is usually 0.1 to 15 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer (A). , Preferably 1 to 10 parts by weight.

<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 plate or the like is further stacked 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 plate.

  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 plate 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. (2) Method of forming a pressure-sensitive adhesive layer by applying a pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer on the conductive layer, and further laminating a substrate on the pressure-sensitive adhesive layer (3) Peeling in advance A pressure-sensitive adhesive layer is formed on the liner, this (pressure-sensitive adhesive layer) is transferred onto the substrate, the release liner is peeled off, and the transferred pressure-sensitive adhesive layer is contacted with the conductive layer. (4) A pressure-sensitive adhesive layer is previously formed on a release liner, this (pressure-sensitive adhesive layer) is transferred onto the conductive layer, and the release liner is peeled off. Furthermore, the transferred adhesive layer is placed together with the conductive layer so that the adhesive layer is in contact with the substrate. How to sticking, and the like.

  Here, 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), the pressure-sensitive adhesive layer-forming component is added. As with the known pressure-sensitive adhesive, it is 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 the (meth) acrylic low molecular weight substance used as necessary in the present invention in the solvent is (meth) acrylic. Since the weight average molecular weight (Mw) of the polymer (A) is low, the concentration of the nonvolatile component 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 10 to 70%, preferably 30 to 60%. The 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 characteristics, the pressure-sensitive adhesive layer in the laminate of the present invention has a thickness within the range of 10 to 1000 μm, preferably within the range of 25 to 500 μm after drying the coating solution. It is obtained by coating so as to have a thickness.

  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 usually cured at a temperature of 0 to 50 ° C. for 1 to 10 days, and crosslinking with a crosslinking agent (B) is performed.

Thereby, the gel fraction of the formed pressure-sensitive adhesive layer is usually in the range of 50 to 80%, preferably 60 to 70%.
[Touch panel]
The touch panel of the present invention is a touch panel including 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 display. It is a laminate. 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. This 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 is usually made of polyethylene terephthalate (PET) as shown in FIG. Or the 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 material having transparency, and as shown in FIG. 1, usually a lower electrode support 25- made of polyethylene terephthalate (PET) or glass. 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 display. The deep surface support 21-2 is made of a transparent material such as glass or polycarbonate. It is formed from a high member.

  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 arranged to face the 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 pressure-sensitive adhesive based on a pressure-sensitive adhesive component that is a polymer having a weight average molecular weight of 400,000 to 1.6 million as in the past, the shape of the pressure-sensitive adhesive layer cannot be changed due to such a very fine change in shape. A gap 64 is formed.

  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 transparent conductive film (which may have a support) are laminated has a specific composition as described above. Since the (meth) acrylic polymer (A) having a weight average molecular weight (Mw) of 50,000 or more and less than 400,000 is used, and preferably a (meth) acrylic low molecular weight material having a specific composition is used. Even in a state where a high cohesive force is imparted by cross-linking with a cross-linking agent (B), it has a very excellent form following ability, and a void 64 may be formed around the frame printing portion 62. Absent.

  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 uses a (meth) acrylic polymer (A) having a specific composition and having a weight average molecular weight (Mw) of 50,000 or more and less than 400,000, and is used as a crosslinking agent (B ) Has a very high cohesive force, and the foaming due to outgas and the growth of entrained bubbles as described above can be suppressed by the high cohesive force. 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%), 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 (FIG. 6). The pressure-sensitive adhesive layer forming the touch panel of the present invention not only has a high cohesive force as described above, but also has a high fluidity due to the low molecular weight of the (meth) acrylic polymer (A), and water is easily dispersed. Since moisture is easily dispersed by the influence of the space of the side chain formed by the bulkiness of the macromer that is a constituent monomer of the (meth) acrylic polymer (A), haze deterioration due to the whitening phenomenon is extremely unlikely to occur.

  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 about 10% at the maximum, and this change amount is an amount that does not cause any problem in driving the touch panel.

  As described above, the touch panel of the present invention is preferably a (meth) acrylic polymer (A) having a specific composition as an adhesive layer and having a weight average molecular weight of 50,000 or more and less than 400,000 and a crosslinking agent (B). A support (base material) and a conductive layer (eg, transparent conductive film) are adhered using a pressure-sensitive adhesive layer having a (meth) acrylic low molecular weight material of the composition, and the pressure-sensitive adhesive layer is excellent. In addition, there is no gap formed in the frame printed part formed at the edge, and it is possible to suppress both foaming due to entrainment and foaming due to outgassing. The pressure-sensitive adhesive layer is hardly whitened and haze is hardly deteriorated due to the bulkiness of the chain.

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.
As shown below, a (meth) acrylic polymer (A) (in a state dissolved in a polymerization solvent as shown in the following production examples), a (meth) acrylic low molecular weight product is produced, and these are crosslinked. The pressure-sensitive adhesive composition was prepared by mixing the agent (B), and the following various characteristics were evaluated.

〔Measuring method〕
<Weight average molecular weight>
The weight average molecular weight (Mw) in terms of standard polystyrene was determined by gel permeation chromatography (GPC) under the following conditions.

(GPC measurement conditions)
Measuring device: HLC-8120GPC (manufactured by Tosoh Corporation)
GPC column configuration: The following five columns (all manufactured by Tosoh Corporation)
(1) TSK-GEL HXL-H (guard column)
(2) TSK-GEL G7000HXL
(3) TSK-GEL GMHXL
(4) TSK-GEL GMHXL
(5) TSK-GEL G2500HXL
Diluted with tetrahydrofuran so that the sample concentration is 1.0 mg / cm ³ Mobile phase solvent: Tetrahydrofuran Flow rate: 1.0 cm ³ / min
Column temperature: 40 ° C.

<Gel fraction>
About 0.1 g of the pressure-sensitive adhesive composition 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 was dried at 100 ° C. for 2 hours, the dry weight was measured, and determined by the following formula.

＜ヘイズ（耐白化性）＞
粘着剤組成物を剥離シート（（シリコーンで剥離処理されたポリエチレンテレフタレート（ＰＥＴ）フィルム）上に塗布し、８０℃条件で５分乾燥して粘着剤層（厚み５０μｍ）を形成し、当該層の剥離シートと接していない面に剥離シートを積層した。

<Haze (whitening resistance)>
The pressure-sensitive adhesive composition was applied on a release sheet ((polyethylene terephthalate (PET) film peel-treated with silicone)) and dried at 80 ° C. for 5 minutes to form a pressure-sensitive adhesive layer (thickness 50 μm). The release sheet was laminated on the surface not in contact with the release sheet.

  The release sheet on one side of the pressure-sensitive adhesive sheet thus obtained was peeled off, and a 25 μm-thick polyethylene terephthalate film was bonded to the exposed pressure-sensitive adhesive layer surface, and cut into a size of 50 mm × 50 mm. Next, the other release sheet was peeled off, and the exposed pressure-sensitive adhesive layer surface was bonded to a 2 mm thick polycarbonate (PC) plate to prepare a test piece. Subsequently, after processing for 20 minutes by an autoclave of 50 degreeC and 5 atm, it left still for 1 hour and created the test piece.

  After measuring the haze before the durability test of the prepared test piece, it was left to stand in an environment of 60 ° C. and humidity of 90%. After 500 hours, the test piece was taken out and allowed to stand at room temperature for 1 hour, and then the haze was measured to determine the difference (degree of whitening) from the haze value before the durability test. In addition, MH-150 (Murakami Color Research Laboratory Co., Ltd. product) was used for the measurement of haze.

<Foaming resistance>
Peel off the release sheet on one side of the pressure-sensitive adhesive sheet obtained in the same manner as described in the section of <Haze>, and paste the ITO-deposited 25 μm thick polyethylene terephthalate film so that the ITO is in contact with the pressure-sensitive adhesive layer. And cut to a size of 50 mm × 50 mm. Next, the other release sheet was peeled off, and the exposed pressure-sensitive adhesive layer surface was bonded to a 2 mm thick PC plate to prepare a test piece. Subsequently, after processing for 20 minutes by an autoclave of 50 degreeC and 5 atm, it left still for 1 hour and created the test piece.

After leaving still in an 80 degreeC environment, the test piece was taken out after 500 hours, and after leaving still at room temperature for 1 hour, the external appearance was observed visually.
(Evaluation) (Content)
A: No bubbles can be visually confirmed in the pressure-sensitive adhesive layer. B: A few bubbles can be visually confirmed. Δ: Although it is practically usable, bubbles can be clearly confirmed visually. X: Large bubbles can be confirmed. Further, the pressure-sensitive adhesive layer floats from the base material or the adherend.

<ITO corrosiveness>
An adhesive sheet obtained by the same method as described in the section of <Haze> is pasted on an ITO-deposited PET film cut to 10 mm × 100 mm, pasted to 10 mm × 60 mm, and autoclaved at 50 ° C. × 5 atm for 20 minutes. Processed. Next, after standing at room temperature for 1 hour, placing it in an environment of 60 ° C. and 90% RH for 500 hours, standing at 23 ° C. and 65% RH for 1 hour, then measuring the resistance value of the ITO deposited film and measuring it in advance Compared with the resistance value before the test, the change rate of the resistance value (resistance value R after the test / resistance value R ₀ × 100 (%) before the test) was obtained. The resistance value was measured using a tester (manufactured by Sanwa Denki Keiki Co., Ltd .; Digital Multimeter PC510).

<Cutability>
The adhesive sheet obtained by the same method as described in the section of <Haze> was punched 30 times with a cutter blade, and adhesion of the adhesive to the cutter blade and the cut surface were visually observed.

(Evaluation) (Content)
○: There is no adhesion of the adhesive to the cutter blade, and the cut surface is not rough.
Δ: Adhesive does not adhere to the cutter blade at all, but the cut surface is rough.
X: Adhesive adherence to the cutter blade was confirmed, and the cut surface was rough.

<Step adhesive strength>
Remove the release sheet on one side of the pressure-sensitive adhesive sheet (the thickness of the pressure-sensitive adhesive layer is 50 μm) obtained in the same manner as described in the section of <Haze>, and bond a PET film with a thickness of 25 μm to the exposed pressure-sensitive adhesive layer surface The test piece was prepared by cutting to a width of 10 mm.

  Next, the other release sheet of the test piece is peeled off, and the adhesive layer exposed at the step portion (step height 30 μm) of the two 25 μm-thick PET films that are adhered to each other with a gap is placed with a width of 25 mm. The test piece was bonded together.

The test piece was peeled off in the 180 ° direction at 300 mm / min from the PET film that had been stuck together, and the adhesive strength (force required for peeling) of the pressure-sensitive adhesive layer was measured.
<Step following capability>
<Peeling the peeled PET film on one side of the pressure-sensitive adhesive sheet obtained by the same method as described in the section of <Haze>, bonding a 25 μm thick PET film, cutting to 50 mm × 50 mm, and removing the test piece Created.

  Next, a 25 μm PET film cut to 25 mm × 25 mm is placed on a glass plate, the peeled PET film on the other side 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. And then left at 80 ° C. for 500 hours, then left at room temperature for 1 hour, and visually observed the stepped portion between the glass plate and the PET film placed on the glass and covered with the test piece. Observed.

(Evaluation) (Content)
A: Bubbles cannot be visually confirmed at the stepped portion.
○: A slight amount of air bubbles can be confirmed at the stepped portion by visual attachment.
X: Large bubbles can be confirmed at the stepped portion. Further, the pressure-sensitive adhesive layer floats from the base material or the adherend.

[Production Examples and Comparative Production Examples] Production of (meth) acrylic polymer (A) and (meth) acrylic low molecular weight <Production Example 1> Production of (meth) acrylic polymer 1 Stirrer, reflux condenser, temperature In a reactor equipped with a meter and a nitrogen introduction tube, 10 parts by weight of a macromer (Tg 105 ° C.) (MMA macromer (weight average molecular weight 10,000)) having methyl methacrylate (MMA) as the main chain, n-butyl acrylate (BA) 16 parts by weight, 70 parts by weight of methoxyethyl acrylate (MEA), 4 parts by weight of 2-hydroxyethyl acrylate (2-HEA), 100 parts by weight of ethyl acetate (EtAc), 20 parts by weight of methyl ethyl ketone (MEK) are charged, and nitrogen gas is added. The temperature was raised to 70 ° C. while introducing.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc), adjusted to a solid content concentration of 30%, and (meth) acrylic polymer 1 having a weight average molecular weight of 300,000 was obtained.

<Production Example 2> Production of (meth) acrylic polymer 2 In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube, a macromer (Tg 105 ° C) with MMA as the main chain (MMA macromer ( Weight average molecular weight 500)) 10 parts by weight, n-butyl acrylate (BA) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and ethyl acetate (EtAc) 100 parts by weight and 20 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 2 having a weight average molecular weight of 300,000.

<Production Example 3> Production of (meth) acrylic polymer 3 In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube, a macromer (Tg 105 ° C.) having MMA as the main chain (MMA macromer ( (Weight average molecular weight 100,000)) 10 parts by weight, n-butyl acrylate (BA) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and ethyl acetate (EtAc) ) 100 parts by weight and 20 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc), adjusted to a solid content concentration of 30%, and (meth) acrylic polymer 3 having a weight average molecular weight of 300,000 was obtained.

<Production Example 4> Production of (meth) acrylic polymer 4 A macromer (Tg 100 ° C.) having styrene (St) as the main chain in a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube ( 10 parts by weight of St macromer (weight average molecular weight 10,000), 16 parts by weight of n-butyl acrylate (BA), 70 parts by weight of methoxyethyl acrylate (MEA), 4 parts by weight of 2-hydroxyethyl acrylate (2-HEA) and acetic acid 100 parts by weight of ethyl (EtAc) and 20 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 4 having a weight average molecular weight of 300,000.

<Production Example 5> Production of (meth) acrylic polymer 5 A macromer having t-BMA (t-butyl methacrylate) as the main chain in a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube ( Tg 110 ° C) (t-BMA macromer (weight average molecular weight 10,000)) 10 parts by weight, n-butyl acrylate (BA) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2- HEA), 4 parts by weight, 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 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 5 having a weight average molecular weight of 300,000.

<Production Example 6> Production of (meth) acrylic polymer 6 In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube, a macromer (Tg 105 ° C.) having MMA as the main chain (MMA macromer ( (Weight average molecular weight 10,000)) 0.1 parts by weight, n-butyl acrylate (BA) 25.9 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and ethyl acetate (EtAc) ) 100 parts by weight and 20 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 6 having a weight average molecular weight of 300,000.

<Production Example 7> Production of (meth) acrylic polymer 7 To a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube, a macromer (Tg 105 ° C.) having MMA as the main chain (MMA macromer ( (Weight average molecular weight 10,000))) 30 parts by weight, n-butyl acrylate (BA) 6 parts by weight, methoxyethyl acrylate (MEA) 60 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and ethyl acetate (EtAc) ) 100 parts by weight and 20 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc), adjusted to a solid content concentration of 30%, and (meth) acrylic polymer 7 having a weight average molecular weight of 300,000 was obtained.

<Production Example 8> Production of (meth) acrylic polymer 8 In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube, a macromer (Tg 105 ° C.) having MMA as the main chain (MMA macromer ( (Weight average molecular weight 10,000))) 10 parts by weight, n-butyl acrylate (BA) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and ethyl acetate (EtAc) ) 100 parts by weight and 20 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 8 having a weight average molecular weight of 300,000.

<Production Example 9> Production of (meth) acrylic polymer 9 In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube, a macromer (Tg 105 ° C.) having MMA as the main chain (MMA macromer ( Weight average molecular weight 10,000)) 10 parts by weight, n-butyl acrylate (BA) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and methyl ethyl ketone (MEK) 150 parts by weight were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc), adjusted to a solid content concentration of 30%, and (meth) acrylic polymer 9 having a weight average molecular weight of 50,000 was obtained.

<Production Example 10> Production of (meth) acrylic polymer 10 In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube, a macromer (Tg 105 ° C) with MMA as the main chain (MMA macromer ( (Weight average molecular weight 10,000))) 10 parts by weight, n-butyl acrylate (BA) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and ethyl acetate (EtAc) ) 110 parts by weight and 10 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 10 having a weight average molecular weight of 380,000.

<Production Example 11> Production of (meth) acrylic polymer 11 In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube, a macromer (Tg 105 ° C.) having MMA as the main chain (MMA macromer ( (Weight average molecular weight 10,000)) 10 parts by weight, n-butyl acrylate (BA) 15 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight, acrylamide (AM) 1 part by weight, 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 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 11 having a weight average molecular weight of 300,000.

<Production Example 12> Production of (meth) acrylic polymer 12 In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube, a macromer (Tg 105 ° C.) having MMA as the main chain (MMA macromer ( (Weight average molecular weight 10,000)) 10 parts by weight, n-butyl acrylate (BA) 11 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight, acrylamide (AM) 5 parts by weight, 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 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 12 having a weight average molecular weight of 300,000.

<Production Example 13> Production of (meth) acrylic polymer 13 In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube, a macromer (Tg 105 ° C.) having MMA as the main chain (MMA macromer ( (Weight average molecular weight 10,000)) 10 parts by weight, n-butyl acrylate (BA) 15 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight, dimethylaminoethyl methacrylate 1 part by weight of (DM), 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 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc), adjusted to a solid content concentration of 30%, and (meth) acrylic polymer 13 having a weight average molecular weight of 300,000 was obtained.

<Comparative Production Example 1> Production of (meth) acrylic polymer 14 A reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introduction tube was charged with 26 parts by weight of n-butyl acrylate (BA), methoxyethyl acrylate ( MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight, ethyl acetate (EtAc) 100 parts by weight, methyl ethyl ketone (MEK) 20 parts by weight, heated to 70 ° C. while introducing nitrogen gas did.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 14 having a weight average molecular weight of 300,000.

<Comparative Production Example 2> Production of (meth) acrylic polymer 15 Macromer with MMA as main chain (Tg 105 ° C) (MMA macromer) in reactor equipped with stirrer, reflux condenser, thermometer and nitrogen inlet tube (Weight average molecular weight 10,000)) 35 parts by weight, n-butyl acrylate (BA) 6 parts by weight, methoxyethyl acrylate (MEA) 55 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and ethyl acetate ( EtAc) (100 parts by weight) and methyl ethyl ketone (MEK) (20 parts by weight) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 15 having a weight average molecular weight of 300,000.

<Comparative Production Example 3> Production of (meth) acrylic polymer 16 Macromer with MMA as main chain (Tg 105 ° C) (MMA macromer) in reactor equipped with stirrer, reflux condenser, thermometer and nitrogen inlet tube (Weight average molecular weight 200)) 10 parts by weight, n-butyl acrylate (BA) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and ethyl acetate (EtAc ) 100 parts by weight and 20 parts by weight of methyl ethyl ketone (MEK) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 16 having a weight average molecular weight of 300,000.

<Comparative Production Example 4> Production of (meth) acrylic polymer 17 Macromer (Tg 105 ° C) with MMA as main chain (MMA macromer) in a reactor equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube (Weight average molecular weight 130,000)) 10 parts by weight, 16 parts by weight of n-butyl acrylate (BA), 70 parts by weight of methoxyethyl acrylate (MEA), 4 parts by weight of 2-hydroxyethyl acrylate (2-HEA) and ethyl acetate ( EtAc) (110 parts by weight) and methyl ethyl ketone (MEK) (10 parts by weight) were charged, and the temperature was raised to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc), adjusted to a solid content concentration of 30%, and (meth) acrylic polymer 17 having a weight average molecular weight of 380,000 was obtained.

<Comparative Production Example 5> Production of (meth) acrylic polymer 18 A reactor equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube was charged with 10 parts by weight of methyl methacrylate (MMA), n-butyl acrylate (BA ) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight, ethyl acetate (EtAc) 100 parts by weight, methyl ethyl ketone (MEK) 20 parts by weight, nitrogen gas The temperature was raised to 70 ° C. while introducing.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 18 having a weight average molecular weight of 300,000.

<Comparative Production Example 6> Production of (meth) acrylic polymer 19 Macromer having MMA as main chain (Tg 105 ° C) (MMA macromer) in a reactor equipped with a stirrer, reflux condenser, thermometer and nitrogen introduction tube (Weight average molecular weight 10,000)) 10 parts by weight, n-butyl acrylate (BA) 15 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight, acrylic acid ( 1 part by weight of AA), 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 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 19 having a weight average molecular weight of 300,000.

<Comparative Production Example 7> Production of (meth) acrylic polymer 20 Macromer (Tg 105 ° C) with MMA as main chain (MMA macromer) in a reactor equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube (Weight average molecular weight 10,000)) 10 parts by weight, n-butyl acrylate (BA) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and methyl ethyl ketone (MEK ) 160 parts by weight were charged and heated to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc) and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer 20 having a weight average molecular weight of 30,000.

<Comparative Production Example 8> Production of (meth) acrylic polymer 21 In a reactor equipped with a stirrer, reflux condenser, thermometer and nitrogen introduction tube, a macromer (Tg 105 ° C) with MMA as the main chain (MMA macromer) (Weight average molecular weight 10,000) 10 parts by weight, n-butyl acrylate (BA) 16 parts by weight, methoxyethyl acrylate (MEA) 70 parts by weight, 2-hydroxyethyl acrylate (2-HEA) 4 parts by weight and ethyl acetate (EtAc ) 110 parts by weight were charged and heated to 70 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with ethyl acetate (EtAc), adjusted to a solid content concentration of 30%, and (meth) acrylic polymer 21 having a weight average molecular weight of 500,000 was obtained.

<Production Example 14> (Meth) acrylic low molecular weight substance A reaction apparatus equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube was mixed with 95 parts by weight of methyl methacrylate (MMA) and dimethylaminoethyl methacrylate (DM) 5 Part by weight and 100 parts by weight of toluene were charged, and the temperature was raised to 85 ° C. while introducing nitrogen gas.

  Next, 0.2 part by weight of azobisisobutyronitrile (AIBN) was added to the reaction solution, and a polymerization reaction was performed at 70 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the reaction solution was diluted with toluene and adjusted to a solid content concentration of 30% to obtain a (meth) acrylic polymer ((meth) acrylic low molecular weight product) having a weight average molecular weight of 10,000.

The amount of monomer used in each of the production examples described above, the weight average molecular weight of the obtained polymer, etc. are summarized in Table 1 below.
[Examples 1 to 13 and Comparative Examples 1 to 8]
Furthermore, in the ratio shown in Table 1, a crosslinking agent was blended with the (meth) acrylic polymer obtained in each production example, and in Example 8, the (meth) acrylic low molecular weight product obtained in Production Example 14 was blended. Thus, a pressure-sensitive adhesive composition was obtained, and the above various characteristics were evaluated.

表１中の略号は以下の通りである。
ＭＭＡ・・・メチルメタクリレート
ＢＡ・・・ブチルアクリレート
ＭＥＡ・・・メトキシエチルアクリレート
２−ＨＥＡ・・・２−ヒドロキシエチルアクリレート
ＡＡ・・・アクリル酸
ＤＭ・・・ジメチルアミノエチルメタクリレート
ＡＭ・・・アクリルアミド
ＭＭＡマクロマー・・・MMAを主鎖とするマクロマー（Tg 105℃）
Ｓｔマクロマー・・・Stを主鎖とするマクロマー（Tg 100℃）
ｔ−ＢＭＡ・・・ｔ−ＢＭＡを主鎖とするマクロマー（Tg 110℃）
ＴＤ−７５・・・キシリレンジイソシアネートのトリメチロールプロパン付加体（綜研化学社製）
なおマクロマーは、その主鎖を構成するモノマーに加えて、カルボキシル基を有する連鎖移動剤チオグリコール酸を用いて重合して得られる、末端にカルボキシル基を有する重合体とグリシジルメタクリレートとを反応させて得られた、末端に不飽和結合を有する重合体である。

Abbreviations in Table 1 are as follows.
MMA ... Methyl methacrylate BA ... Butyl acrylate MEA ... Methoxyethyl acrylate 2-HEA ... 2-Hydroxyethyl acrylate AA ... Acrylic acid DM ... Dimethylaminoethyl methacrylate AM ... Acrylamide MMA Macromer: Macromer with MMA as main chain (Tg 105 ° C)
St macromer: Macromer with St as main chain (Tg 100 ℃)
t-BMA ... Macromer with t-BMA as the main chain (Tg 110 ° C)
TD-75: Trimethylolpropane adduct of xylylene diisocyanate (manufactured by Soken Chemical Co., Ltd.)
In addition to the monomer constituting the main chain, the macromer is obtained by reacting a polymer having a carboxyl group at the terminal with a glycidyl methacrylate obtained by polymerization using a chain transfer agent thioglycolic acid having a carboxyl group. This is a polymer having an unsaturated bond at the terminal.

  Moreover, the unit of Mw is 10,000, and the unit of the step adhesive force is (N / 25 mm). The total monomer used for the polymerization is 100 parts by weight.

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 (14)

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) It is obtained by copolymerizing a monomer containing 0.1 to 10% by weight of a (meth) acrylic monomer having a crosslinkable functional group and 0.1 to 30% by weight of a macromer (with all monomers being 100% by weight). A (meth) acrylic polymer having a weight average molecular weight of substantially 50,000 to less than 400,000
(B) a crosslinking agent,
The macromer has a polymerizable unsaturated group, a glass transition temperature of 50 to 180 ° C., a weight average molecular weight of Ri 500 to 100,000 der, the crosslinkable functional group is a hydroxyl group, the crosslinking agent is an isocyanate A laminate characterized by being a crosslinking agent .   The laminate according to claim 1, wherein the monomer constituting the macromer is a methacrylic monomer or a styrene monomer.   The laminate according to claim 1 or 2, wherein the pressure-sensitive adhesive layer further comprises a (meth) acrylic low molecular weight polymer obtained by polymerizing a monomer containing a nitrogen-containing (meth) acrylic monomer. body. The laminate according to any one of claims 1 to 3, wherein the (meth) acrylic polymer (A) contains a nitrogen-containing monomer as a constituent monomer.   The laminate according to claim 3, wherein the macromer and the (meth) acrylic low molecular weight substance have at least one common constituent monomer. The laminate according to any one of claims 1 to 5 , wherein the conductive layer is a transparent conductive film made of a metal or a metal oxide. The thickness of the said adhesive layer is 10-1000 micrometers, The laminated body in any one of Claims 1-6 characterized by the above-mentioned. In a touch panel comprising a surface support, a pressure-sensitive adhesive layer, and a touch panel unit including a laminate in which a conductive layer is laminated in this order, and a display laminated on the touch panel unit,
Touch panel the laminate, characterized in that a laminate according to any one of claims paragraph 1 - paragraph 7. The touch panel according to claim 8 , wherein the touch panel is a capacitive touch panel. Wherein the laminated body, according to claim 8, wherein a touch panel, or the first 9, wherein the frame print is being made on the edge of the surface facing the pressure-sensitive adhesive layer of the surface support. The thickness of the frame printing, the touch panel according to claim 10 wherein wherein a is in the range of 10 to 50 [mu] m. The conducting layer is a circuit pattern using the tin oxide, ITO or ATO, claim paragraph 8 to 11, wherein, wherein the pressure-sensitive adhesive layer to the circuit pattern in direct contact Touch panel as described in 1. The touch panel according to claim 8, wherein to 12 wherein the thickness of the surface support is characterized in that in the range of 25～2000Myuemu. The touch panel according to claim 12, wherein the thickness of the circuit pattern which is the conductive layer is in a range of 10 to 100 nm.

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