JP2016191070A - Acrylic resin composition and applications using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic layer used for the production of an active energy ray-curing type solvent-based acrylic pressure-sensitive adhesive which can obtain a clean pressure-sensitive adhesive layer even by thick coating and does not require aging. A resin composition is provided. An active energy ray-reactive acrylic resin (A), an organic solvent (B) having a boiling point of 120 ° C. or lower, and a flash point of 100 ° C. or higher, and a glass transition temperature of a single polymer is −80. It contains an ethylenically unsaturated compound (C) containing one ethylenically unsaturated group at -40 ° C, and the active energy ray-reactive acrylic resin (A) is an ethylenically unsaturated group-containing acrylic resin. (A1), the active energy ray-reactive acrylic resin (A) has a weight average molecular weight of 300,000 to 5,000,000, and the content of the organic solvent (B) is the active energy ray-reactive acrylic resin (A). 80 to 1000 parts by weight with respect to 100 parts by weight, and the content of the ethylenically unsaturated compound (C) is 8 to 85% by weight with respect to the entire acrylic resin composition -Based resin composition. [Selection figure] None

Description

  The present invention relates to an acrylic resin composition, an acrylic pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, a double-sided pressure-sensitive adhesive sheet, and a method for producing a pressure-sensitive adhesive sheet, and more specifically, an active energy ray-curable solvent-based acrylic suitable for thick coating. It is related with the acrylic resin composition used for manufacture of a system adhesive.

  Conventionally, acrylic adhesives are strong adhesives that are intended to bond adherends firmly for a long period of time, or peel-off types based on the premise that they are peeled off from adherends after being attached. There are various types of pressure-sensitive adhesives such as pressure-sensitive adhesives, and pressure-sensitive adhesives having optimized adhesive properties are designed and used in various fields.

  In recent years, the properties required of adhesives include not only adhesive properties such as adhesive strength, but also transparency and impact resistance to the adhesive layer itself when used for bonding glass substrates in liquid crystal display devices and the like. Absorptivity is required.

For example, in mobile devices such as TVs, monitors for personal computers, notebook computers, mobile phones, and tablet terminals, a protective layer formed from a plastic sheet or the like is usually provided on the viewing side of the liquid crystal display, or due to external impacts. In order to prevent damage to the liquid crystal display, a space (air layer) is provided between the liquid crystal display and the protective layer.
However, there is a problem that reflection occurs at the interface between the protective layer and the air layer and at the interface between the air layer and the liquid crystal display, resulting in a decrease in visibility. Therefore, the impact-absorbing pressure-sensitive adhesive layer described above is used instead of the air layer for the purpose of improving visibility and further reducing the thickness of the plastic sheet (mobile device) while ensuring impact resistance. In order to improve the shock-absorbing performance, it has been proposed to increase the thickness of the pressure-sensitive adhesive layer.

  As a method for thickening the adhesive layer using an acrylic resin (coating a thick film), a dilution monomer ((meth) acrylic acid derivative ((meth) acrylic acid derivative (B)) is added to an acrylic resin ((meth) acrylic acid derivative polymer (B)). A)) and a solvent-free active energy ray-curable pressure-sensitive adhesive comprising a polyfunctional compound (polyfunctional (meth) acrylic acid derivative (C)) as a curing component is known (for example, patents) Reference 1).

  The active energy ray-curable pressure-sensitive adhesive generally does not contain a solvent used for viscosity adjustment with a normal acrylic pressure-sensitive adhesive, and a photopolymerizable unsaturated monomer as a dilution monomer instead of the solvent. Since it is a solvent-free pressure-sensitive adhesive used, there is no need for a drying step to remove the solvent after coating the pressure-sensitive adhesive, and it is possible to obtain a pressure-sensitive adhesive layer efficiently in a short time even when thick coating is applied. It can be done.

JP 2009-57550 A

  However, acrylic resins that can be used as solvent-free pressure-sensitive adhesives are only acrylic resins produced by a fairly limited method, such as (i) acrylic resins produced by bulk polymerization, (Ii) Once an acrylic resin was produced by solution polymerization or suspension polymerization, it was necessary to use an acrylic resin produced by drying and removing the solvent.

Here, in the case of producing by the method (i), it is difficult to produce an acrylic resin with good reproducibility due to poor polymerization stability, the reaction heat is difficult to control and the safety is low, and there are many reaction components. However, there was a problem that it was difficult to remove heat and production efficiency was poor.
Furthermore, even in the case of producing by the method (ii), large energy and time are required to remove the solvent and water from the acrylic resin containing the solvent (solvent and water) once produced, and the production efficiency is poor. there were. In particular, it is very difficult to completely remove the remaining solvent from the acrylic resin in which a certain amount of solvent has been removed and the viscosity becomes high, and the residual solvent may adversely affect the physical properties of the adhesive. In addition, acrylic resins with a low glass transition temperature, which are mainly used as pressure-sensitive adhesives, cause the polymer to agglomerate and dry up when dried up, making it difficult to handle and re-dissolving in the monomer. Was difficult and time consuming.

  Therefore, solvent-free pressure-sensitive adhesives are suitable for thick coating, but have the problem that the degree of freedom of acrylic resins that can be used is low, and acrylic pressure-sensitive adhesives having desired physical properties can be obtained. Since it was difficult, it was possible to design acrylic resin freely, and in terms of enabling more efficient production, a solvent that can use acrylic resin (solvent-containing one) produced by solution polymerization. This type of adhesive was more preferable than the solventless adhesive.

  However, when using solvent-based adhesives for thick coating applications, the adhesive layer is thick at the time of coating, so the solvent is less likely to volatilize during the drying process after coating, and foams into the adhesive layer. More specifically, the solvent on the surface of the pressure-sensitive adhesive layer is volatilized and the surface becomes hard, so that bubbles that try to evaporate from below or inside the pressure-sensitive adhesive layer remain inside the pressure-sensitive adhesive layer. There was a problem that the phenomenon that happens.

  Therefore, in the present invention, under such a background, it is possible to apply thick coating, to obtain a beautiful pressure-sensitive adhesive layer on the surface of the coating film, and further, an active energy ray curing type that does not require aging. It aims at providing the manufacturing method of the acrylic resin composition used for manufacture of a solvent-type acrylic adhesive, the acrylic adhesive using the same, an adhesive sheet, a double-sided adhesive sheet, and an adhesive sheet.

  However, as a result of intensive studies in view of such circumstances, the present inventor has obtained further general drying on a solvent-based pressure-sensitive adhesive made of an active energy ray-reactive acrylic resin produced by solvent polymerization that is generally used. By adding an ethylenically unsaturated monomer that does not easily volatilize under conditions, the adhesive layer surface is hardened when the adhesive is thickly coated and then dried, preventing the viscosity of the adhesive layer from rising too much. As a result, it is found that the solvent easily evaporates even during thick coating, and that it is excellent in drying suitability. Further, aging is achieved by using a photoreactive acrylic resin as the acrylic resin. Thus, the present invention has been completed by finding that it is a very useful pressure-sensitive adhesive.

That is, the gist of the present invention is an active energy ray-reactive acrylic resin (A), an organic solvent (B) having a boiling point of 120 ° C. or lower, and a flash point of 100 ° C. or higher, and a glass transition of a single polymer. Contains an ethylenically unsaturated compound (C) containing one ethylenically unsaturated group having a temperature of −80 to 40 ° C. (hereinafter sometimes referred to as “monofunctional unsaturated compound (C)”). The active energy ray-reactive acrylic resin (A) is an ethylenically unsaturated group-containing acrylic resin (A1), and the active energy ray-reactive acrylic resin (A) has a weight average molecular weight of 300,000 to 5 million, the content of the organic solvent (B) is 80 to 1000 parts by weight with respect to 100 parts by weight of the active energy ray-reactive acrylic resin (A), and the content ratio of the ethylenically unsaturated compound (C) But acrylic Relates acrylic resin composition characterized by for the entire resin composition is 8-85 wt%.
Furthermore, it is related with the manufacturing method of the acrylic adhesive obtained using an acrylic resin composition, an adhesive sheet, a double-sided adhesive sheet, and an adhesive sheet.

Since the acrylic resin composition of the present invention contains an ethylenically unsaturated monomer that is difficult to volatilize under general drying conditions, a solvent-based acrylic pressure-sensitive adhesive containing an acrylic resin produced by ordinary solvent polymerization However, it is excellent in coating suitability at the time of thick coating, which has been difficult to achieve, and further, since a reactive acrylic resin that can be cured by irradiation with active energy rays is used, aging is not required.
That is, even when thick coating is performed using such an active energy ray-reactive acrylic resin composition and an acrylic pressure-sensitive adhesive is obtained, the pressure-sensitive adhesive due to dripping, coating streaks, and concentrated foaming of the solvent during coating The layer is not disturbed, and the solvent can be easily dried. Furthermore, the obtained pressure-sensitive adhesive layer has excellent durability, adhesive strength, holding power, transparency, corrosion resistance, and the like. .

The present invention will be described in detail below, but these show examples of desirable embodiments.
In the present invention, (meth) acryl means acryl or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate.

  The active energy ray-reactive acrylic resin (A) used in the present invention can react with a part of the acrylic resin or other curing component contained in the acrylic resin composition by irradiation with active energy rays. An acrylic resin having a structural part.

  The reactive structural site contained in the active energy ray-reactive acrylic resin (A) is required to be an ethylenically unsaturated group because it has high reactivity and does not require aging.

  Hereinafter, the ethylenically unsaturated group-containing acrylic resin (A1) will be described as the active energy ray-reactive acrylic resin (A).

The ethylenically unsaturated group-containing acrylic resin (A1) may be an acrylic resin containing an ethylenically unsaturated group in the molecule, for example, an acrylic resin (x) having a functional group in the molecule, It is obtained by reacting an ethylenically unsaturated compound (y) having a functional group that reacts with such a functional group in the molecule (hereinafter sometimes referred to as “ethylenically unsaturated compound (y)”). .
Examples of the acrylic resin (x) having a functional group in the molecule include a functional group-containing ethylenically unsaturated monomer (x1) and a (meth) acrylic acid ester monomer (x2), and further other copolymerization properties as required. It is a polymer obtained by copolymerizing the monomer (x3).

  Examples of the functional group-containing ethylenically unsaturated monomer (x1) include (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, (meth) acrylamide N-glycolic acid, cinnamon Acid, (meth) acrylic acid Michael adduct (eg (meth) acrylic acid dimer, (meth) acrylic acid trimer, (meth) acrylic acid tetramer, 2- (meth) acryloyloxyethyl dicarboxylic acid monoester (eg 2- (meth) acryloyloxyethyl succinic acid monoester, 2- (meth) acryloyloxyethyl phthalic acid monoester, 2- (meth) acryloyloxyethyl hexahydrophthalic acid monoester, etc.) Saturated monomer, 2-hydroxyethyl (meth) acrylate 2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxy3-phenoxypropyl (meth) acrylate, diethylene glycol (meth) acrylate, polyethylene Hydroxyl group-containing unsaturated monomers such as glycol (meth) acrylate and N-methylol (meth) acrylamide, glycidyl group-containing unsaturated monomers such as glycidyl (meth) acrylate and allyl glycidyl (meth) acrylate, 2- (meth) acryloyloxy Isocyanate group-containing unsaturated monomers such as ethyl isocyanate, (meth) acrylamide, N- (n-butoxyalkyl) (meth) acrylamide, (meth) acrylamide-3-methylbutane Amide group-containing unsaturated monomers such as rumethylamine, dimethylaminoalkyl (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, 2- Sulfonic acid group-containing unsaturated monomers such as (meth) acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid or salts thereof, and amino group-containing unsaturated monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate Among them, at least one selected from these is used, among them, a carboxyl group-containing unsaturated monomer, a hydroxyl group-containing unsaturated monomer, a glycidyl group-containing unsaturated monomer, an isocyanate group-containing unsaturated monomer. Nomers and amide group-containing unsaturated monomers are preferably used.

  As (meth) acrylic acid ester monomer (x2), (meth) acrylic acid alkyl ester, (meth) acrylic acid ester containing alicyclic ring, (meth) acrylic acid ester containing aromatic ring, 2-methoxyethyl (Meth) acrylate, 3-methoxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, etc. are mentioned.

  Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid alkyl esters, particularly (meth) acrylic acid alkyl esters having 1 to 12 carbon atoms, preferably 4 to 12 carbon atoms, and specific examples. N-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-propyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Examples include n-octyl (meth) acrylate and lauryl (meth) acrylate.

  (Meth) acrylic acid ester containing the above alicyclic, specifically, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, cyclopentanyl (meth) acrylate, cyclopentenyl (meth) acrylate, alkylene oxide group thereof Examples thereof include unsaturated monomers.

  Examples of the (meth) acrylic acid ester containing the aromatic ring include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyldiethylene (meth) acrylate, and biphenyloxyethyl (meth) acrylate.

  Examples of other copolymerizable monomers (x3) include (meth) acryloylmorpholine, N- (meth) acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, dimethylallyl vinyl ketone, N-vinylpyrrolidone, and vinyl propionate. , Vinyl stearate, vinyl chloride, vinylidene chloride, vinyl acetate, styrene and the like.

  The above functional group-containing ethylenically unsaturated monomer (x1), acrylate monomer (x2), and other copolymerizable monomer (x3), if necessary, have a functional group in the molecule. An acrylic resin (x) is obtained.

  In the copolymerization, in the organic solvent, the functional group-containing ethylenically unsaturated monomer (x1) and the acrylate monomer (x2), if necessary, other copolymerizable monomers (x3), polymerization start An agent (azobisisobutyronitrile, azobisisovaleronitrile, benzoyl peroxide, etc.) is mixed or dropped and polymerized at reflux or at 50 to 90 ° C. for 4 to 20 hours.

  As the content ratio of the functional group-containing ethylenically unsaturated monomer (x1), the acrylate monomer (x2), and other copolymerizable monomers (x3), the functional group-containing ethylenically unsaturated monomer (x1) is 0. 0.1 to 50% by weight (preferably 0.5 to 10% by weight), acrylic acid ester monomer (x2) is 50 to 99.9% by weight (preferably 90 to 99.5% by weight), and other copolymers The functional monomer (x3) is preferably 0 to 40% by weight (preferably 0.1 to 20% by weight).

  The ethylenically unsaturated group-containing acrylic resin (A1) is an ethylenically unsaturated compound (y) having a functional group that reacts with a functional group in the molecule on the acrylic resin (x) having a functional group in the molecule. As the ethylenically unsaturated compound (y), the above carboxyl group-containing unsaturated monomer, hydroxyl group-containing unsaturated monomer, glycidyl group-containing unsaturated monomer, isocyanate group-containing unsaturated monomer, amide group Examples thereof include an unsaturated monomer containing amino group, an unsaturated monomer containing amino group, and an unsaturated monomer containing sulfonic acid group.

  Urethane which is a reaction product of an isocyanate compound such as tolylene diisocyanate, isophorone diisocyanate or adduct or isocyanurate thereof, and the above-mentioned hydroxyl group-containing unsaturated monomer or hydroxyl group and a compound having a plurality of (meth) acryloyl groups An acrylate-type isocyanate group-containing unsaturated oligomer can also be used.

  Among these, it is preferable to use an isocyanate group-containing unsaturated compound such as an isocyanate group-containing unsaturated monomer or an isocyanate group-containing unsaturated oligomer because the acrylic resin (x) and the ethylenically unsaturated compound (y) are easily reacted. .

For example, when the functional group in the acrylic resin (x) is a carboxyl group, the glycidyl group-containing unsaturated monomer or the isocyanate group-containing unsaturated monomer is used, and when the functional group is a hydroxyl group, the isocyanate group-containing unsaturated monomer is used. When the functional group is a glycidyl group, a carboxyl group-containing unsaturated monomer or an amide group-containing unsaturated monomer is selected, and when the functional group is an amino group, a glycidyl group-containing unsaturated monomer is selected and used. In particular, when the functional group in the acrylic resin (x) is a hydroxyl group, the ethylenically unsaturated compound (y) is preferably an isocyanate group-containing unsaturated compound from the viewpoint of excellent reactivity of the functional group.
However, it is not limited to these.

In preparing the ethylenically unsaturated group-containing acrylic resin (A1), the acrylic resin (x) having a functional group in the molecule and the ethylenically unsaturated compound (y) are reacted. Such a reaction is usually performed at 20 to 80 ° C. for about 1 to 100 hours, and a catalyst may be appropriately used as necessary.
In the reaction, 0.001 to 10 parts by weight of the ethylenically unsaturated compound (y) is preferably reacted with 100 parts by weight of the acrylic resin (x), particularly preferably 0.02 to 2 parts by weight. Parts, more preferably 0.05 to 0.5 parts by weight. When the amount of the ethylenically unsaturated compound (y) is too small, the durability tends to decrease due to insufficient cohesive force, and when the amount is too large, the crosslinking density increases too much and the tackiness tends to decrease.

  In addition, as a method of containing an unsaturated group, as a material which can be efficiently made, as a functional group, an acrylic resin (x) containing a hydroxyl group and / or a carboxyl group and an isocyanate group and / or an epoxy group were contained. A method obtained by reacting with a (meth) acrylic monomer is preferable, and it is particularly preferable to react an acrylic resin (x) containing a hydroxyl group with a (meth) acrylic monomer containing an isocyanate group.

  The weight average molecular weight of the active energy ray-reactive acrylic resin (A) in the present invention is 300,000 to 5,000,000, preferably 300,000 to 1,500,000, particularly preferably 500,000 to 700,000. If the weight average molecular weight is too small, the durability performance tends to be lowered. If the weight average molecular weight is too large, a large amount of diluent solvent is required, the coating property is lowered, and thick coating tends to be difficult.

  The dispersity (weight average molecular weight / number average molecular weight) of the active energy ray-reactive acrylic resin (A) is preferably 20 or less, particularly preferably 15 or less, more preferably 10 or less, Is preferably 7 or less. When the degree of dispersion is too high, the durability performance of the pressure-sensitive adhesive layer is lowered, and foaming or the like tends to occur. The lower limit of the degree of dispersion is usually 1.1 from the viewpoint of production limit.

  Furthermore, the glass transition temperature of the active energy ray-reactive acrylic resin (A) is preferably −80 to 10 ° C., particularly −60 to −10 ° C., more preferably −40 to −20 ° C. If the temperature is too high, tack tends to be insufficient, and if it is too low, the heat resistance tends to decrease.

Ｔg：共重合体のガラス転移温度（Ｋ）
Ｔga：モノマーＡのホモポリマーのガラス転移温度（Ｋ） Ｗa：モノマーＡの重量分率
Ｔgb：モノマーＢのホモポリマーのガラス転移温度（Ｋ） Ｗb：モノマーＢの重量分率
Ｔgn：モノマーＮのホモポリマーのガラス転移温度（Ｋ） Ｗn：モノマーＮの重量分率
（Ｗa＋Ｗb＋・・・＋Ｗn＝１） In addition, said weight average molecular weight is a weight average molecular weight by standard polystyrene molecular weight conversion, and it is a column in high performance liquid chromatography (The Japan Waters company "Waters 2695 (main body)" and "Waters 2414 (detector)"). : Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / piece, filler material: styrene-divinylbenzene copolymer, filler The particle diameter is measured by using three series of 10 μm), and the same method can be used for the number average molecular weight. The degree of dispersion is determined from the weight average molecular weight and the number average molecular weight. The glass transition temperature is calculated from the following Fox equation.

Tg: Glass transition temperature of copolymer (K)
Tga: Glass transition temperature of monomer A homopolymer (K) Wa: Weight fraction of monomer A Tgb: Glass transition temperature of homopolymer of monomer B (K) Wb: Weight fraction of monomer B Tgn: Homogeneity of monomer N Glass transition temperature of polymer (K) Wn: weight fraction of monomer N (Wa + Wb +... + Wn = 1)

  When the pressure-sensitive adhesive obtained from the acrylic resin composition of the present invention is used as a base material or an adherend, such as an easily corroded metal or metal oxide such as ITO or copper, the above active energy ray reaction It is preferable that the functional acrylic resin (A) contains substantially no acid component.

  In addition, specifically, it means that the acid value is not more than 10 mgKOH / g, particularly preferably not more than 1 mgKOH / g, more preferably not more than 0.1 mgKOH / g.

  The organic solvent (B) used in the present invention may be an organic solvent used when the active energy ray-reactive acrylic resin (A) is produced by solution polymerization, or the produced active energy ray reactivity. It may be an organic solvent used for diluting the acrylic resin (A), and is blended when the active energy ray reactive acrylic resin (A) and the ethylenically unsaturated compound (C) described later are mixed. Although it may be an organic solvent, it is substantially an organic solvent used when producing an active energy ray-reactive acrylic resin (A) by solution polymerization because it is economically superior. Is preferred.

The boiling point of the organic solvent (B) is required to be 120 ° C. or less, particularly preferably 100 ° C. or less, and more preferably 85 ° C. or less, because it easily evaporates during coating drying and has excellent drying properties. . If the boiling point is too high, the solvent tends to remain when an adhesive sheet is produced. Moreover, it is preferable that a lower limit is 40 degreeC or more normally at the point of safety | security.
In addition, the said boiling point shall be a boiling point when measured by a normal pressure (1 atmosphere), and the measurement should just be performed according to JISK5601-2-3.

  Specifically, as the organic solvent (B), ester solvents such as ethyl acetate (boiling point 77 ° C.), methyl acetate (boiling point 54 ° C.), butyl acetate (boiling point 126 ° C.); acetone (boiling point 56 ° C.), methyl ethyl ketone ( Ketone solvents such as methyl isobutyl ketone (boiling point 114-117 ° C); heptane (boiling point 98 ° C), hexane (boiling point 67 ° C), cyclohexane (boiling point 81 ° C), methylcyclohexane (boiling point 101 ° C) Aliphatic hydrocarbon solvents such as toluene (boiling point 111 ° C.), xylene (boiling point 144 ° C.), etc .; methanol (boiling point 65 ° C.), ethanol (boiling point 78 ° C.), isopropyl alcohol (boiling point) 83 ° C), alcohol solvents such as isobutanol (108 ° C), sec-butanol (100 ° C), etc. The value of a point is the value of the described in the "coating raw materials Handbook 7th edition, Nippon Paint Manufacturers Association".).

  Among these, in terms of versatility, coating suitability, and polymerization suitability, ester solvents, ketone solvents, and aromatic hydrocarbon solvents are preferable, and ester solvents and ketone solvents are particularly preferable. More preferably, ethyl acetate, acetone, and methyl ethyl ketone are preferable because they have an optimum boiling point and can be obtained in large quantities at a low cost.

The content of the organic solvent (B) needs to be 80 to 1000 parts by weight, particularly preferably 80 to 500 parts by weight with respect to 100 parts by weight of the active energy ray-reactive acrylic resin (A). More preferably, it is 80 to 250 parts by weight, particularly preferably 120 to 180 parts by weight.
If the content of the organic solvent (B) is too large, the coating viscosity tends to decrease too much, so that thick coating tends to be difficult. If it is too small, the active energy ray-reactive acrylic resin (A) is obtained by solution polymerization. When manufacturing, the safety and flexibility of manufacturing tend to decrease.

The ethylenically unsaturated compound (C) containing one ethylenically unsaturated group having a flash point of 100 ° C. or higher used in the present invention has a flash point of 100 ° C. or higher and one ethylenically unsaturated group. Any compound may be used.
In addition, let this flash point be the value of the flash point when measured by the Cleveland open method (JISK2265-4).

In order to improve the drying property of the organic solvent (B), the monofunctional unsaturated compound (C) used in the present invention is coated and dried (especially when thick film is coated). It does not volatilize and tends to stay in the adhesive layer.
For example, butyl acrylate (flash point: 47 ° C.) and 2-ethylhexyl acrylate (flash point: 88 ° C.), which are general monofunctional ethylenically unsaturated compounds, are usually applied due to their high volatility. The monofunctional unsaturated compound (C) used in the present invention usually has a flash point of 100 ° C. or higher, whereas it is volatilized together with the organic solvent under the drying conditions in the process drying step. Under these drying conditions, it is difficult to volatilize with the organic solvent and can remain in the pressure-sensitive adhesive layer.

  In general, the volatility of a compound is generally determined from the boiling point or evaporation rate. However, unsaturated monomers (ethylenically unsaturated compounds) are polymerized when subjected to temperature at normal pressure and the boiling point is reduced. Since it may not be measured accurately, the flash point correlated with the volatility of the unsaturated monomer is used as an indicator of volatility in the present invention.

  The flash point needs to be 100 ° C. or higher, particularly preferably 120 ° C. or higher, and more preferably 140 ° C. or higher. If the flash point is too low, it tends to volatilize in the drying process. The upper limit of the normal flash point is 350 ° C.

  Monofunctional unsaturated compounds (C) include (meth) acrylic acid ester compounds (C1) having one ethylenically unsaturated group (excluding (C2) described later) and ethylenic compounds containing nitrogen atoms. It is preferable to use an unsaturated compound (C2).

  Examples of the (meth) acrylic acid ester compound (C1) having one ethylenically unsaturated group include a long-chain aliphatic (meth) acrylate (C1-1) and an alicyclic (meth) acrylate (C1-2). , Aromatic (meth) acrylate (C1-3), and oxyalkylene structure-modified compounds (C1-4) of these (meth) acrylates.

  Examples of the long chain aliphatic (meth) acrylate (C1-1) include decane (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl acrylate, tridecyl methacrylate, and isomyristyl acrylate (flash point). 129 ° C), isomyristyl methacrylate, n-stearyl acrylate (flash point: 181 ° C), n-stearyl methacrylate, isostearyl acrylate (flash point: 154 ° C), isostearyl methacrylate, and the like.

  Examples of the alicyclic (meth) acrylate (C1-2) include isobornyl acrylate (113 ° C.), isobornyl methacrylate, dicyclopentanyl acrylate (132 ° C.), dicyclopentanyl methacrylate, and dicyclopentenyl. Examples include acrylate (131 ° C.) and dicyclopentenyl methacrylate.

  Examples of the aromatic (meth) acrylate (C1-3) include biphenyl (meth) acrylate, naphthalene (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and 3-chloro-2-hydroxypropyl ( And (meth) acrylate.

As the oxyalkylene structure-modified compound (C1-4) of the above (C1-1) to (C1-3), as the oxyalkylene structure-modified compound of (C1-1), for example, 2-ethylhexyl diethylene glycol acrylate (151 ° C.) 2-ethylhexyl diethylene glycol methacrylate, methoxytriethylene glycol acrylate (143 ° C), methoxytriethylene glycol methacrylate, ethoxydiethylene glycol acrylate (113 ° C), ethoxydiethylene glycol methacrylate, alkyl polyethylene glycol (meth) acrylate, methoxydipropylene glycol acrylate (102 ° C), methoxydipropylene glycol methacrylate, alkylene glycol monoalkyl ester (meth) a Relate, alkylene glycol mono (meth) acrylate, and the like. Examples of the (C1-2) oxyalkylene structure-modified compound include t-butylcyclohexyloxyethyl (meth) acrylate, cyclohexyloxyalkyl (meth) acrylate, and dicyclohexane. Examples include pentenyloxyethyl acrylate (166 ° C.), dicyclopentenyloxyethyl methacrylate, dicyclopentanyloxyethyl (meth) acrylate, and the like (C1-3) as an oxyalkylene (alkyl) structure-modified compound, for example, benzyl Acrylate (108 ° C), benzyl methacrylate, phenoxyethyl acrylate (141 ° C), phenoxyethyl methacrylate, phenyldiethylene glycol acrylate (173 ° C), Rudiethylene glycol methacrylate, phenyltriethylene glycol (meth) acrylate, phenyltetraglycol (meth) acrylate, biphenyloxyethyl acrylate, nonylphenol ethylene oxide modified (repeat 4) acrylate (223 ° C.), nonylphenol ethylene oxide modified (repeat 4) methacrylate, Nonylphenol ethylene oxide modified (repeated 8) acrylate (304 ° C.), nonylphenol ethylene oxide modified (repeated 8) methacrylate, and the like.
In addition, although the flash point was described in parentheses for the acrylate compound, the flash point is usually higher for the methacrylate compound corresponding to the acrylate compound having the flash point described.

  Among these (meth) acrylic acid ester compounds (C1) having one ethylenically unsaturated group, long chain aliphatic (meth) acrylates (C1-1), (C1-2) and (C1-3) It is preferable to use an oxyalkylene structure-modified compound (C1-4) from the viewpoint that stable adhesive strength can be obtained, and particularly preferred is isomyristyl acrylate, tridecyl acrylate, isostearyl acrylate, phenyldiethylene glycol acrylate, dicyclopentenyloxy. Ethyl acrylate.

  The ethylenically unsaturated compound (C2) containing the nitrogen atom can improve the adhesive strength of the pressure-sensitive adhesive when used. For example, acrylamide (134 ° C.), methacrylamide, butoxymethyl acrylamide (112 ° C.) , Hydroxyethyl acrylamide (189 ° C.), dimethylaminopropyl acrylamide (140 ° C.), diacetone acrylamide (110 ° C.) and other acrylamide unsaturated monomers, N-acryloyloxyethyl hexahydrophthalimide (190 ° C.), acryloyl morpholine ( 130 ° C.) and oxazolidone acrylate. Among these, the use of an acrylamide unsaturated monomer is preferable because it is difficult to volatility and has a good balance in adhesive performance, and is particularly preferably butoxymethyl acetate. Is Ruamido.

  Moreover, when using the adhesive obtained using the acrylic resin composition of this invention for a strong adhesive use, the content rate of (C2) with respect to the whole monofunctional unsaturated compound (C) is 1-90 weight. %, Particularly preferably 5 to 80% by weight, more preferably 15 to 70% by weight, particularly preferably 30 to 65% by weight. If the content ratio of (c2) is too large or too small, the adhesive strength is difficult to increase, and the required adhesive strength tends to be difficult to obtain.

The weight molecular weight of the monofunctional unsaturated compound (C) is preferably 150 to 2,000, particularly preferably 200 to 1,500, and further preferably 250 to 700.
If the weight average molecular weight is too large, the pressure-sensitive adhesive properties tend to decrease, and if it is too small, it tends to volatilize in the drying step.

In addition, the monofunctional unsaturated compound (C) is cured by active energy rays and / or heat as described later, whereby (C) a single polymer, (A) and (C) in the pressure-sensitive adhesive layer. Although it exists as a polymer, it is necessary to select the monofunctional unsaturated compound (C) so that the glass transition temperature (Tg) of the polymer (C) alone is -80 to 40 ° C. It is.
Such a glass transition temperature is particularly preferably −60 to 20 ° C., more preferably −40 to 10 ° C., and particularly preferably −15 to 5 ° C. If it is too low, the cohesive force tends to be insufficient.
The glass transition temperature is calculated from the Fox equation described above.

In the present invention, the content ratio (weight ratio) of the active energy ray-reactive acrylic resin (A) and the monofunctional unsaturated compound (C) is (A) :( C) = 10: 90 to 75:25. Preferably, (A) :( C) = 20: 80 to 70:30, more preferably (A) :( C) = 25: 75 to 68:32, particularly preferably. (A) :( C) = 30: 70 to 49:51.
If the content of the monofunctional unsaturated compound (C) with respect to the active energy ray-reactive acrylic resin (A) is too small, thick coating is difficult and the effect of the present invention tends not to be sufficiently exerted, If the amount is too large, the viscosity tends to be too low and thick coating tends to be difficult.

In addition, the total amount of the active energy ray-reactive acrylic resin (A) and the monofunctional unsaturated compound (C) is preferably 20% by weight or more with respect to the entire components (A) to (C). Particularly preferably, it is 40% by weight or more, more preferably 60% by weight or more, and the upper limit of the content is usually 98% by weight.
If the ratio of the total amount of the active energy ray-reactive acrylic resin (A) and the monofunctional unsaturated compound (C) with respect to the entire components (A) to (C) is too low, thick coating becomes difficult. It tends to be difficult to obtain a thick adhesive layer.

  The content ratio of the active energy ray-reactive acrylic resin (A) with respect to the entire acrylic resin composition is usually 5 to 40% by weight, preferably 8 to 30% by weight, and particularly preferably 10 to 20% by weight. If the content is too high, the viscosity tends to increase too much and the coating suitability tends to decrease. If the content is too small, the viscosity tends to decrease too much and the coating suitability tends to decrease.

  The content of the organic solvent (B) with respect to the entire acrylic resin composition is usually 10 to 90% by weight, preferably 15 to 50% by weight, and particularly preferably 20 to 35% by weight. If the content is too high, the coating concentration tends to be too low and the coating suitability tends to be lowered. If the content is too small, the viscosity tends to be too high and the coating suitability tends to be lowered.

  The content ratio of the monofunctional unsaturated compound (C) with respect to the entire acrylic resin composition is 8 to 85% by weight, preferably 8 to 60% by weight, and particularly preferably 20 to 40% by weight. If the content is too high, the content of (A) tends to be too low and the adhesive properties tend to decrease. If it is too low, the drying property tends to be low, and coating with a thick film tends to be difficult.

The acrylic resin composition of the present invention preferably has a viscosity of 20,000 mPa · s / 25 ° C. or less from the viewpoint of coating properties, particularly preferably 15,000 mPa · s / 25 ° C. or less, and more preferably. Is 10,000 mPa · s / 25 ° C. or lower. Usually, the lower limit of the viscosity is 10 mPa · s / 25 ° C.
If the viscosity is too high, the coating tends to be difficult due to, for example, the appearance of coating stripes.

  Thus, an acrylic resin composition comprising the active energy ray-reactive acrylic resin (A), the organic solvent (B), and the monofunctional unsaturated compound (C) of the present invention is obtained.

  In the present invention, the acrylic resin composition is cured by curing the acrylic resin composition containing the active energy ray-reactive acrylic resin (A), the organic solvent (B), and the monofunctional unsaturated compound (C). (However, when the organic solvent (B) is volatilized in the drying step after coating and then cured, the organic solvent (B) is substantially contained in the acrylic resin composition at the time of curing. Is not included in the list.)

  As such a curing method, a method of curing with active energy rays may be used, and further curing with heat may be used in combination. However, in terms of energy amount and productivity, active energy rays (active energy ray irradiation) ) Is preferred.

  Furthermore, the acrylic resin composition contains an ethylenically unsaturated compound (D) containing two or more ethylenically unsaturated groups (hereinafter sometimes abbreviated as “polyfunctional unsaturated compound (D)”). It is preferable that the cohesive force of the entire pressure-sensitive adhesive layer can be adjusted, and that the polymerization initiator (E) is contained can stabilize the reaction during irradiation with active energy rays and / or heating. preferable.

  As the polyfunctional unsaturated compound (D), for example, an ethylenically unsaturated monomer containing two or more ethylenically unsaturated groups in one molecule, for example, a bifunctional monomer, a trifunctional or higher monomer, Urethane (meth) acrylate compounds, epoxy (meth) acrylate compounds, and polyester (meth) acrylate compounds can be used. Among these, it is preferable to use an ethylenically unsaturated monomer and a urethane (meth) acrylate-based compound from the viewpoint of excellent curing rate and ultimate physical properties.

  The bifunctional monomer may be any monomer containing two ethylenically unsaturated groups. For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene Oxide modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate 1,6-hexanediol ethylene oxide modified di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di ( (Meth) acrylate, diglycidyl phthalate di (meth) acrylate, hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, isocyanuric acid ethylene oxide-modified diacrylate, 2- (meth) acryloyloxyethyl acid phosphate diester It is done.

  The tri- or higher functional monomer may be any monomer containing three or more ethylenically unsaturated groups. For example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) ) Acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, Glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ethylene oxide modified dipentaerythritol (Meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol tetra (meth) acrylate, succinic acid modified pentaerythritol tri (meth) acrylate Etc.

  The urethane (meth) acrylate compound is a (meth) acrylate compound having a urethane bond in the molecule, a (meth) acrylic compound containing a hydroxyl group and a polyvalent isocyanate compound (if necessary, a polyol What is necessary is just to use what is obtained by making it react by a well-known general method, and what is necessary is just to use the thing of 300-4,000 normally as the weight average molecular weight.

  The content of the polyfunctional unsaturated compound (D) is preferably 0.01 to 100 parts by weight, particularly preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the active energy ray-reactive acrylic resin (A). 1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight. When the content of the polyfunctional unsaturated compound (D) is too large, the cohesive force is excessively increased, so that the adhesive performance tends to be lowered. When the content is too small, the holding power tends to be lowered.

  The content of the polyfunctional unsaturated compound (D) is desirably 0.01 to 99 parts by weight, preferably 0.1 to 100 parts by weight of the monofunctional unsaturated compound (C). -10 parts by weight, more preferably 0.5-5 parts by weight. If the content of the polyfunctional unsaturated compound (D) is too large, the cohesive force of the pressure-sensitive adhesive tends to increase too much, and the adhesive performance tends to decrease. If it is too small, the cohesive force is insufficient, resulting in durability. Tends to decrease.

  As the polymerization initiator (E), for example, various polymerization initiators such as a photopolymerization initiator (e1) and a thermal polymerization initiator (e2) can be used. It is preferable to use e1) in that it can be cured by irradiation with active energy rays such as ultraviolet rays for a very short time.

  When the photopolymerization initiator (e1) is used, the acrylic resin composition is cured by irradiation with active energy rays. When the thermal polymerization initiator (e2) is used, the acrylic resin composition is cured by heating. However, it is also preferable to use both in combination as necessary.

  Examples of the photopolymerization initiator (e1) include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4- Acetophenones such as morpholinophenyl) butanone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl Ben such as ether Ins; benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium Benzophenones such as chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy -3 Thioxanthones such as 4-dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl- And acyl phosphine oxides such as pentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; In addition, these photoinitiators (e1) may be used individually by 1 type, and 2 or more types may be used together.

  These auxiliary agents include triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler ketone), 4,4′-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, 4-dimethylaminobenzoic acid. Ethyl, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone Etc. can be used in combination.

  Among these, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoyl isopropyl ether, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1- It is preferable to use phenylpropan-1-one.

  The content of the polymerization initiator (E) is about 100 parts by weight of the monofunctional unsaturated compound (C) (when the polyfunctional unsaturated compound (D) is used, (C) and (D) Is preferably from 0.01 to 50 parts by weight, particularly preferably from 0.1 to 20 parts by weight, still more preferably from 0.3 to 12 parts by weight, particularly preferably 0. It is preferable that it is 5-3 weight part. If the content of the polymerization initiator (E) is too small, the curability tends to be poor and the physical properties tend to be less stable, and if it is too much, no further effect tends to be obtained.

  In the active energy ray irradiation, far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays and other electromagnetic waves, X rays, γ rays and other electromagnetic waves, as well as electron beams, proton rays, neutron rays, etc. can be used. Curing by ultraviolet irradiation is advantageous from the standpoint of availability of the device and price. In addition, when performing electron beam irradiation, it can harden | cure even without using the said photoinitiator (e1).

As a light source for the ultraviolet irradiation, a high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, or the like is used. For the high-pressure mercury lamp, for example, 5~3000mJ / cm ^2, preferably at the conditions of 50~2000mJ / cm ^2. Moreover, in the case of the said electrodeless lamp, it is 2-2000 mJ / cm < ² >, for example, Preferably it carries out on the conditions of 10-1000 mJ / cm < ² >. The irradiation time varies depending on the type of the light source, the distance between the light source and the coating surface, the coating thickness, and other conditions, but it may be usually from several seconds to several tens of seconds, and in some cases, a fraction of a second. On the other hand, in the case of the electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 Kev is used, and the irradiation amount is preferably 2 to 50 Mrad.

  Moreover, when using a thermal-polymerization initiator (e2) as said polymerization initiator (E), a polymerization reaction is started and advanced by heating. The treatment temperature and treatment time at the time of curing by heating vary depending on the type of the thermal polymerization initiator (e2) to be used, and are usually calculated from the half-life of the initiator, but the treatment temperature is usually The temperature is preferably 70 ° C to 170 ° C, and the treatment time is usually preferably 0.2 to 20 minutes, and particularly preferably 0.5 to 10 minutes.

  Further, the acrylic resin composition of the present invention includes a silane coupling agent, an antistatic agent, other acrylic pressure-sensitive adhesives, other pressure-sensitive adhesives, urethane resins, rosins, and rosins, as long as the effects of the present invention are not impaired. Esters, hydrogenated rosin esters, phenol resins, aromatic modified terpene resins, aliphatic petroleum resins, alicyclic petroleum resins, styrene resins, xylene resins, tackifiers, colorants, fillers, anti-aging Conventionally known additives such as oxidants, ultraviolet absorbers, functional dyes, and the like, and compounds that cause coloration or discoloration upon irradiation with ultraviolet rays or radiation can be blended. The total content is preferably 30% by weight or less, particularly preferably 20% by weight or less, and low molecular components having a molecular weight lower than 10,000 as an additive are contained as much as possible. It is preferred from the viewpoint of excellent durability.

  In addition to the above additives, a small amount of impurities contained in the raw materials for producing the constituent components of the acrylic resin composition may be contained.

  When the pressure-sensitive adhesive obtained from the acrylic resin composition is used for a substrate such as ITO or copper that is easily corroded or a metal oxide, or an adherend, the acrylic resin composition is It is preferable that the acid component is not substantially contained.

  In addition, specifically, it means that the acid value is not more than 10 mgKOH / g, particularly preferably not more than 1 mgKOH / g, more preferably not more than 0.1 mgKOH / g.

  As described above, the acrylic resin composition is cured (cross-linked) to obtain an acrylic pressure-sensitive adhesive.

  The acrylic pressure-sensitive adhesive of the present invention is preferably used as a pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive layer made of an acrylic pressure-sensitive adhesive and a substrate.

  As a method for producing such an adhesive sheet, it can be produced according to a known general method for producing an adhesive sheet. For example, after an acrylic resin composition is provided on a substrate, it is dried, and then heat and / or active energy rays are used. Is obtained by irradiation.

  Examples of the substrate on which the acrylic resin composition is provided include polyester resins such as polyethylene naphthalate, polyethylene terephthalate, boribylene terephthalate, and polyethylene terephthalate / isophthalate copolymer; polyolefins such as polyethylene, polypropylene, and polymethylpentene. -Based resins: Polyfluorinated ethylene resins such as polyvinyl fluoride, polyvinylidene fluoride, and polyfluorinated ethylene; Polyamides such as nylon 6, nylon 6, 6; Polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymer, ethylene-vinyl acetate Copolymers, ethylene-vinyl alcohol copolymers, vinyl polymers such as polyvinyl alcohol and vinylon; cellulose resins such as cellulose triacetate and cellophane; polymethyl methacrylate, polymethacrylic acid Acrylic resins such as chill, polyethyl acrylate, and polybutyl acrylate; polystyrene; polycarbonate; polyarylate; synthetic resin sheets such as polyimide, aluminum, copper, and iron metal foils, high-quality paper, glassine paper, and glass, glass Examples thereof include woven fabrics and nonwoven fabrics made of fibers, natural fibers, synthetic fibers, and the like. These base materials can be used as a single layer body or a multilayer body in which two or more kinds are laminated.

  In the present invention, the acrylic pressure-sensitive adhesive is preferably used as a pressure-sensitive adhesive for optical members. By forming a pressure-sensitive adhesive layer made of the acrylic pressure-sensitive adhesive on the optical member, an optical with a pressure-sensitive adhesive layer is formed. A member can be obtained.

Such optical members include transparent electrode films such as ITO conductive films such as ITO electrode films and polythiophenes, polarizing plates, retardation plates, elliptical polarizing plates, optical compensation films, brightness enhancement films, electromagnetic wave shielding films, and near-infrared absorbing films. And AR (anti-reflection) film. Among these, when it is a transparent electrode film, the effect of this invention can be exhibited notably and it is preferable at the point from which high adhesive force is acquired, Especially preferably, it is an ITO (indium tin oxide) electrode film.
Here, when the reactive acrylic resin (A) and the monofunctional unsaturated compound (C) do not contain an acidic group, corrosion is particularly difficult to occur.

  In the optical member with the pressure-sensitive adhesive layer, it is preferable to further provide a release sheet on the surface opposite to the optical member surface of the pressure-sensitive adhesive layer. An adhesive layer and an adherend will be bonded. As such a release sheet, a silicon-based release sheet is preferably used.

  In preparing the optical member with the pressure-sensitive adhesive layer to which the release sheet is bonded, for the method of curing the acrylic resin composition, [1] on the optical member, after applying and drying the resin composition, A method of pasting a release sheet and performing treatment by at least one of active energy ray irradiation and heating. [2] After applying and drying a resin composition on the release sheet, an optical member is pasted and activated. A method of performing treatment by at least one of energy ray irradiation and heating; [3] a resin composition is coated on an optical member, dried, and further subjected to treatment by at least one of active energy ray irradiation and heating; [4] A resin composition is applied onto a release sheet, dried, and further subjected to treatment with at least one of active energy ray irradiation and heating, followed by optical treatment. How to bonding the wood can be produced by,. Among these, the case of performing only the active energy ray irradiation by the method [2] is preferable from the viewpoint of not damaging the substrate, workability and stable production.

  About the drying conditions in the said drying process, drying temperature is 50 to 250 degreeC normally, Preferably it is 60 to 150 degreeC, More preferably, it is 65 to 120 degreeC, Most preferably, it is 70 to 95 degreeC. The time is usually 10 seconds to 10 minutes, but drying at a low temperature for a long time can volatilize and remove the organic solvent (B), and the pressure-sensitive adhesive without volatilizing the monofunctional unsaturated compound (C). This is preferable in that it can remain in the layer. In consideration of economy and production efficiency, it is preferable that the drying time is short.

  The acrylic resin composition is applied by a conventional method such as roll coating, die coating, gravure coating, comma coating, or screen printing.

  Up to here, after manufacturing the optical member with the pressure-sensitive adhesive layer once the release sheet is bonded, the pressure-sensitive adhesive that bonds the pressure-sensitive adhesive layer and the adherend (other optical members) after peeling off the release sheet. In the present invention, it is also preferable to produce a double-sided pressure-sensitive adhesive sheet using the acrylic pressure-sensitive adhesive, and a method of bonding optical members using the double-sided pressure-sensitive adhesive sheet. Also good.

  As such a double-sided pressure-sensitive adhesive sheet, a double-sided pressure-sensitive adhesive sheet having a known general configuration may be applied using the above acrylic pressure-sensitive adhesive, but in particular, it is excellent in transparency and has a high adhesive force with respect to the thickness to constitute. A double-sided pressure-sensitive adhesive sheet is preferred. Such a substrate-less double-sided pressure-sensitive adhesive sheet is formed by forming a pressure-sensitive adhesive layer made of the above acrylic pressure-sensitive adhesive on a release sheet, and then sticking another release sheet to the side of the pressure-sensitive adhesive layer that does not have a release sheet. It can be obtained by combining. As for the method of use, after peeling off one release sheet and bonding it to the adherend, the other release sheet may be peeled off and bonded to the adherend.

  About the gel fraction of the said adhesive sheet, the adhesive layer of an optical member with an adhesive layer, and the adhesive layer of a double-sided adhesive sheet, it is preferable that it is 30 to 98% from the point of durable performance and adhesive force, Especially. It is preferably 50 to 90%, particularly preferably 60 to 80%. If the gel fraction is too low, durability tends to be insufficient due to insufficient cohesive force. On the other hand, if the gel fraction is too high, the adhesive force tends to decrease due to an increase in cohesive force.

  In adjusting the gel fraction of the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive for optical members, and the double-sided pressure-sensitive adhesive sheet to the above range, for example, the type of ethylenically unsaturated compound (D) containing two or more ethylenically unsaturated groups And by adjusting the amount.

  The gel fraction is a measure of the degree of crosslinking (curing degree), and is calculated, for example, by the following method. That is, a pressure-sensitive adhesive sheet (not provided with a separator) in which a pressure-sensitive adhesive layer is formed on a polymer sheet (for example, polyethylene terephthalate film or the like) as a base material is wrapped with a 200-mesh SUS wire mesh, and 23 in toluene. The weight percentage of the insoluble pressure-sensitive adhesive component immersed in the wire mesh at 24 ° C. for 24 hours is defined as the gel fraction. However, the weight of the substrate is subtracted.

The thickness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet, the optical member with the pressure-sensitive adhesive layer, and the double-sided pressure-sensitive adhesive sheet is usually preferably 5 to 3000 μm, particularly preferably 50 to 1000 μm, and more preferably 100 to 500 μm. Preferably there is.
If the thickness of the pressure-sensitive adhesive layer is too thin, the impact absorbability tends to be insufficient, and if it is too thick, the thickness of the entire optical member tends to increase too much.

  In addition, in the acrylic resin composition of the present invention, as described above, since it contains an ethylenically unsaturated monomer that is difficult to volatilize under general drying conditions, it is excellent in drying suitability during thick coating, This makes it possible to obtain a thick adhesive layer that could not be obtained by coating and drying with a conventional solvent-based acrylic adhesive composition.

When obtaining the above thick adhesive layer, it is preferably applied with a film thickness of 100 μm or more, particularly preferably 200 μm or more, more preferably 300 μm or more, and the film thickness of the adhesive layer obtained after drying. The thickness is preferably 50 μm or more, particularly preferably 100 μm or more, and further preferably 200 μm or more.
As the upper limit of the film thickness, the film thickness at the time of coating is usually 3000 μm, and the film thickness after drying is usually 2000 μm.
In particular, when used for applications such as shock absorption and air gap filling, the thickness of the pressure-sensitive adhesive layer after drying is preferably 100 μm or more, particularly preferably 200 μm or more. Is usually 2000 μm.

  The adhesive strength of the pressure-sensitive adhesive layer of the present invention is appropriately determined according to the material of the adherend, and is adhered to, for example, a PET sheet on which a glass substrate, a polycarbonate plate, a polymethyl methacrylate plate, or an ITO layer is deposited. In some cases, the adhesive strength is preferably 5 N / 25 mm to 500 N / 25 mm, and more preferably 10 N / 25 mm to 100 N / 25 mm.

  The adhesive strength is calculated as follows. A 100 μm-thick polyethylene terephthalate (PET) sheet with a 100 μm thick adhesive layer-formed PET is cut to a width of 25 mm, the release sheet is peeled off, and the adhesive layer side is covered with the above-mentioned coated layer. The above adhesive sheet of 25 mm × 100 mm was applied to the body by pressurizing and reciprocating 2 kg rubber rollers in an atmosphere of 23 ° C. and 50% relative humidity, and left in the same atmosphere for 30 minutes, and then peeled at a room temperature of 300 mm / min. 180 degree peel strength (N / 25mm) was measured.

  The total transmittance of the pressure-sensitive adhesive layer of the present invention is preferably 90% or more, particularly preferably 92% or more. If the total line transmittance is too low, the transmittance is low, so that it tends to be difficult to use in display applications. The upper limit of the total light transmittance is usually 95%.

  The haze value of the pressure-sensitive adhesive layer of the present invention is preferably 10% or less, particularly preferably 2% or less, and further preferably 1% or less. If the haze is too high, the image tends to become unclear when used for display. The lower limit of the haze value is usually 0.00%.

  Here, the above-mentioned total line transmittance and haze value are values measured using a haze meter based on JIS K7361-1.

The color difference b value of the pressure-sensitive adhesive layer of the present invention is preferably 1 or less, particularly preferably 0.5 or less. If the color difference b value is too high, the original color tends to be difficult to be obtained when used for display. The lower limit of the color difference b value is normally -1.
Here, the color difference b value was measured in accordance with JIS K7105, and the measurement was performed under transmission conditions using a color difference meter (Σ90: manufactured by Nippon Denshoku Industries Co., Ltd.).

  In the present invention, the haze, total light transmittance, and color difference b value are measured using alkali-free glass (total light transmittance = 93, haze = 0.06, b value = 0.16) for the pressure-sensitive adhesive layer alone. It is the value measured by sticking to.

  In addition, when the acrylic resin composition of the present invention is cured, an active energy ray reactive acrylic resin (A), an organic solvent (B), an ethylenically unsaturated group having a flash point of 100 ° C. or higher. Polymer containing one ethylenically unsaturated compound (C) containing one ethylenically unsaturated compound (C) containing one ethylenically unsaturated group having a flash point of 100 ° C. or higher It is preferable that the pressure-sensitive adhesive sheet is characterized by having a pressure-sensitive adhesive layer containing.

  In this case, the content of the organic solvent (B) with respect to the entire pressure-sensitive adhesive layer is preferably 0.0001 to 1% by weight, and one ethylenically unsaturated group having a flash point of 100 ° C. or higher with respect to the entire pressure-sensitive adhesive layer. The content of the ethylenically unsaturated compound (C) contained is preferably 0.01 to 3% by weight.

  The acrylic pressure-sensitive adhesive composed of the acrylic resin composition of the present invention includes glass, ITO transparent electrode sheet, optical sheets such as polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polarizing plate, It is useful for attaching optical members such as a retardation plate, an optical compensation film, and a brightness enhancement film. Furthermore, it can be suitably used for an image display device such as a touch panel including these optical members.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the examples, “parts” and “%” mean weight basis unless otherwise specified.

  First, various active energy ray reactive acrylic resin (A) solutions (including an organic solvent (B)) were prepared as follows. In addition, about the measurement of the weight average molecular weight of acrylic resin, a number average molecular weight, and a glass transition temperature, it measured according to the above-mentioned method.

  In addition, regarding the measurement of solid content concentration, take 1 to 2 g of acrylic resin solution on aluminum foil, heat-dry with a ket (infrared dryer, 185 W, height 5 cm) for 45 minutes, measure the weight change before and after drying, Regarding the measurement of the viscosity, it was measured according to the 4.5.3 rotational viscometer method of JIS K5400 (1990).

[Preparation of Active Energy Ray Reactive Acrylic Resin (A) Solution (Including Organic Solvent (B))] (See Table 1)

[Active energy ray-reactive acrylic resin (A-1) solution]
In a four-necked round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, methyl acrylate (x2) 40 parts, n-butyl acrylate (x2), 59 parts, 2-hydroxyethyl acrylate (X1) 1 part and 120 parts of ethyl acetate were added, and after heating and refluxing were started, 0.1 part of azobisisobutyronitrile was added as a polymerization initiator, and the mixture was reacted at ethyl acetate reflux temperature for 3 hours. Add 0.1 parts of nitrile and 20 parts of ethyl acetate, react for another 4 hours, dilute with ethyl acetate, and prepare acrylic resin (x-1) solution (weight average molecular weight 550,000, dispersity 4.3, glass transition A temperature of -34 ° C, a solid content of 38%, and a viscosity of 8000 mPa · s (25 ° C)) were obtained.
To 100 parts (resin content) of the obtained acrylic resin (x-1) solution, 0.08 part of dibutylhydroxytoluene and 0.07 part of 2-methacryloyloxyethyl isocyanate (y-1) were charged, and 30 at 50 ° C. Reacted for hours. Active energy ray-reactive acrylic resin (A-1) solution in which 5 mol% of ethylenically unsaturated groups are added to the side chain with respect to hydroxyethyl acrylate (x1) (resin content 38%, viscosity 8000 mPa · s (25 ° C. )).

[Active energy ray reactive acrylic resin (A-2)]
0.08 part of dibutylhydroxytoluene and 0.14 part of 2-methacryloyloxyethyl isocyanate (y-1) are charged into 100 parts (resin content) of the acrylic resin (x-1) solution and reacted at 50 ° C. for 30 hours. I let you. Active energy ray-reactive acrylic resin (A-2) solution in which 10 mol% of ethylenically unsaturated groups are added to the side chain with respect to hydroxyethyl acrylate (x1) (resin content 38%, viscosity 8000 mPa · s (25 ° C)).

[Active energy ray reactive acrylic resin (A-3)]
0.08 part of dibutylhydroxytoluene and 0.28 part of 2-methacryloyloxyethyl isocyanate (y-1) are charged in 100 parts of the acrylic resin (x-1) solution (resin content) and reacted at 50 ° C. for 30 hours. I let you. Active energy ray-reactive acrylic resin (A-3) solution in which 20 mol% of ethylenically unsaturated groups are added to the side chain with respect to hydroxyethyl acrylate (x1) (resin content 38%, viscosity 8000 mPa · s (25 ° C)).

[Active energy ray reactive acrylic resin (A-4)]
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 48 parts of tolylene diisocyanate, 0.05 parts of di-t-butylhydroxyphenol, 20 parts of toluene, dibutyltin dilaurate 0.02 part was charged, and 32 parts of 2-hydroxyethyl acrylate was added dropwise at about 50 ° C. in about 3 hours. The reaction was continued at 50 ° C., and the reaction was completed when the residual isocyanate group reached 11.6%. Thus, an unsaturated group-containing compound (y-2) (solid content 80%, viscosity 280 mPa · s (25 ° C.)) was obtained.
To 100 parts of the acrylic resin (x-1) solution (resin part), 0.14 part of an unsaturated group-containing compound (y-2) was charged and reacted at 50 ° C. for 30 hours. Active energy ray-reactive acrylic resin (A-4) solution in which 6 mol% of ethylenically unsaturated groups are added to the side chain with respect to hydroxyethyl acrylate (x1) (resin content 38%, viscosity 8000 mPa · s (25 ° C)).

[Active energy ray reactive acrylic resin (A-5) solution]
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, n-butyl acrylate (x2), 92 parts, acrylic acid (x1) 8 parts and ethyl acetate 120 parts. Charge and start heating under reflux, add 0.1 part of azobisisobutyronitrile as a polymerization initiator, react for 3 hours at reflux temperature of ethyl acetate, then add 0.1 part of azobisisobutyronitrile and 20 parts of ethyl acetate. In addition, the mixture was further reacted for 4 hours and diluted with ethyl acetate to obtain an acrylic resin (x-2) solution (weight average molecular weight 690,000, dispersity 5.2, glass transition temperature-50 ° C., solid content 38%, viscosity 8000 mPa · s (25 ° C.)) was obtained.
To 100 parts (resin content) of the resulting acrylic resin (x-2) solution, 0.08 part of dibutylhydroxytoluene and 0.14 part of 2-methacryloyloxyethyl isocyanate (y-1) were charged, and the mixture was 30 at 50 ° C. Reacted for hours. Active energy ray-reactive acrylic resin (A-5) solution (resin content 38%, viscosity 8000 mPa · s (25 ° C.) added 5% by mole of ethylenically unsaturated group to the side chain with respect to hydroxyethyl acrylate (x1) )).

[Organic solvent (B)]
The following were prepared as the organic solvent (B).
B-1: ethyl acetate (boiling point: 77 ° C.)

[Monofunctional unsaturated compound (C)]
The following were prepared as the monofunctional unsaturated compound (C-1).
・ Isomyristyl acrylate (C1-1; manufactured by Kyoeisha Chemical Co., Ltd., “Light acrylate IM-A”)
The following were prepared as the monofunctional unsaturated compound (C-2).
Isostearyl acrylate (C1-1; manufactured by Osaka Organic Chemical Co., “ISTA”)
The following were prepared as the monofunctional unsaturated compound (C-3).
・ Butoxymethylacrylamide (C2; manufactured by Kasano Kosan Co., Ltd., “NBM-2”)
The following were prepared as the monofunctional unsaturated compound (C-4).
N-acryloyloxyethyl hexahydrophthalimide (C2; manufactured by Toagosei Co., Ltd., “M-140”)
The following were prepared as monofunctional unsaturated compounds (C-5).
Phenyl diethylene glycol acrylate (C1-4; manufactured by Kyoeisha Chemical Co., Ltd., “Light acrylate P2HA”)
The following were prepared as monofunctional unsaturated compounds (C-6). Dicyclopentenyloxyethyl acrylate (C1-4; manufactured by Hitachi Chemical Co., Ltd., “FA-512AS”)

  The flash points and molecular weights of the monofunctional unsaturated compounds (C-1) to (C-6) are shown in Table 2 below.

[Compound (D) containing two or more ethylenically unsaturated groups]
D-1: Trimethylolpropane triacrylate

[Photoinitiator (E)]
A 1: 1 mixture of E-1: 1-hydroxycyclohexyl phenyl ketone and benzophenone (Ciba Japan, “Irgacure 500”)

[Examples 1-8, Comparative Examples 1-3]
An acrylic resin composition solution was prepared by blending the blended components prepared and prepared as described above in the proportions shown in Table 3 below.

Then, the acrylic resin composition solution obtained above was applied to a polyester release sheet so that the thickness after drying was 100 μm, and dried at 100 ° C. for 5 minutes to form an adhesive layer. .
The coating suitability when forming the pressure-sensitive adhesive layer was evaluated as follows.

[Coating suitability]
The appearance of the pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer was formed under the above drying conditions was visually evaluated.
◎: A clean pressure-sensitive adhesive layer was obtained. ○: Slightly small bubbles were confirmed. △: Bubbles were clearly confirmed. ×: It was confirmed that a large amount of bubbles were bitten.

In Examples 1 to 8 and Comparative Examples 1 and 2, the obtained pressure-sensitive adhesive layer was sandwiched between polyester release sheets, and the peak illuminance was 150 mW / cm ^{2 with} a high-pressure mercury UV irradiation apparatus, and the cumulative exposure amount was 1000 mJ / Ultraviolet irradiation was carried out at cm ² (500 mJ / cm ² × 2 passes) to obtain a substrate-less double-sided pressure-sensitive adhesive sheet.
In Comparative Example 3, the obtained pressure-sensitive adhesive composition layer was sandwiched between polyester release sheets, and 23 ° C. × 65% R.D. H. A baseless double-sided PSA sheet was obtained by aging under the conditions of 10 days.

Using the substrate-less double-sided pressure-sensitive adhesive sheet obtained above, a PET film with a pressure-sensitive adhesive layer was prepared as follows, and the gel fraction, accelerated gel fraction, adhesive strength, and retention strength were measured according to the following methods. ·evaluated.
In addition, each measurement other than the accelerated gel fraction was measured after 23 ° C. × 18 to 30 hours after coating on the polyester-based release sheet. Since it has been aged for 10 days, it is a measured value after aging.
These results are also shown in Table 3 below.

[Preparation of PET film with adhesive layer]
The release sheet on one side was peeled off from the pressure-sensitive adhesive of the substrate-less double-sided pressure-sensitive adhesive sheet and pressed against a 100 μm PET film to obtain a PET film with a pressure-sensitive adhesive layer.

[Gel fraction]
After cutting the PET film with the pressure-sensitive adhesive layer to 40 × 40 mm, the release sheet is peeled off, the pressure-sensitive adhesive layer side is bonded to a 50 × 100 mm SUS mesh sheet (200 mesh), and then the length of the SUS mesh sheet is increased. The sample was wrapped from the center with respect to the direction, and the sample was wrapped. Then, the gel fraction (%) was measured by the change in weight when immersed in a sealed container containing 250 g of toluene.

[Accelerated gel fraction]
After the PET film with the pressure-sensitive adhesive layer was prepared, it was allowed to stand at 40 ° C. for 7 days, and then the same evaluation as the measurement of the gel fraction was performed.

[Adhesive force]
The PET film with the pressure-sensitive adhesive layer was cut into a width of 25 mm and a length of 100 mm, the release sheet was peeled off, and the pressure-sensitive adhesive layer side was placed on soda glass at 23 ° C. and a relative humidity of 50% in a 2 kg rubber roller 2 After applying pressure by reciprocating and leaving it in the same atmosphere for 30 minutes, 180 degree peel strength (N / 25 mm) was measured at a peel rate of 300 mm / min at room temperature.

[Retention force]
The PET film with the pressure-sensitive adhesive layer is cut to 25 mm × 25 mm, the release sheet is peeled off, the pressure-sensitive adhesive layer side is attached to a polished SUS plate, and a load of 1 kg is applied at 80 ° C. Then, the deviation was evaluated according to the measuring method of the holding power of JIS Z 0237. The evaluation criteria are as follows.
(Evaluation)
○ ・ ・ ・ No deviation occurs after 1440 minutes △ ・ ・ ・ Deformation occurs after 1440 minutes × ・ ・ ・ Drops by 1440 minutes

  Using the substrate-less double-sided pressure-sensitive adhesive sheet obtained above, an alkali-free glass plate with a pressure-sensitive adhesive layer was prepared as follows, and the total light transmittance, haze, and color chain b value were measured according to the following methods. evaluated. These results are also shown in Table 3 below.

[Preparation of non-alkali glass plate with adhesive layer]
The substrate-less double-sided pressure-sensitive adhesive sheet is cut out to 3 cm × 4 cm, the light release release sheet is peeled off, and the pressure-sensitive adhesive layer side is pressed against an alkali-free glass plate (Corning Corp., Eagle XG), and further peeled off. The mold sheet was peeled off to obtain an alkali-free glass plate with an adhesive layer.

[Total light transmittance] and [Haze]
The diffuse transmittance and total light transmittance of the alkali-free glass plate with the pressure-sensitive adhesive layer were measured using HAZE MATER NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). In addition, this machine is JIS
Conforms to K7361-1.
The values of the obtained diffuse transmittance and total light transmittance were substituted into the following formula to calculate haze.
Haze value (%) = (diffuse transmittance / total light transmittance) × 100

[Color difference b value]
The color difference b value of the alkali-free glass plate with the pressure-sensitive adhesive layer was measured according to JIS K7105. The measurement was performed under transmission conditions using a color difference meter (Σ90: manufactured by Nippon Denshoku Industries Co., Ltd.).

  In addition, only the glass plate WHEREIN: The value at the time of measuring the said total light transmittance, haze, and color difference b value was 93% of total light transmittance, haze 0.1%, and color difference b value 0.2.

  In Table 3 above, the numbers (A) to (E) and the crosslinking agent indicate parts by weight, and “*” indicates that the pressure-sensitive adhesive layer is foamed and cannot be measured. Further, as the crosslinking agent of Comparative Examples 1 and 3, a 55% ethyl acetate solution of trimethylolpropane tolylene diisocyanate adduct (manufactured by Nippon Polyurethane Co., Ltd., “Coronate L-55E”) was used.

The acrylic resin compositions of Examples 1 to 8 have a clean adhesive layer even when a thick adhesive layer is formed so that the thickness after drying is 100 μm. It can be seen that the film is excellent in holding power and optical characteristics.
Moreover, since it is not necessary to age by using active energy ray reactive acrylic resin (A), it can be utilized as an adhesive sheet immediately after coating.

  On the other hand, Comparative Example 1 in which acrylic resin (x-1) was crosslinked with a crosslinking agent resulted in inferior holding power immediately after coating, and the gel fraction was changed by the accelerated test, and aging In Comparative Example 2 in which the acrylic resin (x-1) is not cross-linked with a cross-linking agent, it is difficult to use as an adhesive sheet because the physical properties are not stable for a certain period after coating. It can be seen that the adhesive strength is poor.

Further, in the pressure-sensitive adhesive layer of Comparative Example 3 obtained by using the acrylic resin composition not containing the monofunctional unsaturated compound (C), entrapment of a large amount of bubbles was confirmed, and it was clean during thick film coating. The pressure-sensitive adhesive layer could not be obtained, and was inferior in drying suitability.
As a result, it can be seen that these pressure-sensitive adhesive layers are not practical for optical applications due to the bubbles generated in the pressure-sensitive adhesive layer, although they have excellent pressure-sensitive adhesive properties.

  The acrylic pressure-sensitive adhesive composed of the acrylic resin composition of the present invention can be suitably used as a pressure-sensitive adhesive sheet, in particular, a double-sided pressure-sensitive adhesive sheet, especially a double-sided pressure-sensitive adhesive sheet that does not have a base material (no base material), Glass, ITO transparent electrode sheet, polyethylene terephthalate (PET), polycarbonate (PC) in terms of high adhesive strength, excellent heat resistance reliability and impact resistance reliability, high light transmission, and less haze generation It is useful for attaching optical members such as optical sheets such as polymethylmethacrylate (PMMA), polarizing plates, retardation plates, optical compensation films, and brightness enhancement films. Furthermore, it can be suitably used for a touch panel including these optical members. Furthermore, since aging is not required, it is excellent in productivity.

Claims (8)

Active energy ray reactive acrylic resin (A),
An organic solvent (B) having a boiling point of 120 ° C. or lower, and ethylene containing one ethylenically unsaturated group having a flash point of 100 ° C. or higher and a single polymer having a glass transition temperature of −80 to 40 ° C. A unsaturated unsaturated compound (C),
The active energy ray-reactive acrylic resin (A) is an ethylenically unsaturated group-containing acrylic resin (A1),
The active energy ray-reactive acrylic resin (A) has a weight average molecular weight of 300,000 to 5,000,000,
The content of the organic solvent (B) is 80 to 1000 parts by weight with respect to 100 parts by weight of the active energy ray-reactive acrylic resin (A),
The acrylic resin composition, wherein the content of the ethylenically unsaturated compound (C) is 8 to 85% by weight with respect to the entire acrylic resin composition.   An ethylenically unsaturated compound having a functional group that reacts with a functional group in the molecule with respect to 100 parts by weight of the acrylic resin (x) having an ethylenically unsaturated group-containing acrylic resin (A1). The acrylic resin composition according to claim 1, wherein the acrylic resin composition is obtained by reacting 0.01 to 10 parts by weight of y).   The content ratio (weight ratio) of the active energy ray-reactive acrylic resin (A) and the ethylenically unsaturated compound (C) is (A) :( C) = 10: 90 to 75:25, The acrylic resin composition according to claim 1 or 2.   4. The weight molecular weight of the ethylenically unsaturated compound (C) containing one ethylenically unsaturated group having a flash point of 100 ° C. or higher is 150 to 2,000. 5. Acrylic resin composition.   An acrylic pressure-sensitive adhesive obtained from the acrylic resin composition according to claim 1.   The acrylic resin composition according to any one of claims 1 to 4, comprising an ethylenically unsaturated compound (D) containing two or more ethylenically unsaturated groups and a polymerization initiator (E), an active energy ray and An acrylic pressure-sensitive adhesive that is cured by heat.   A double-sided pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer containing the acrylic pressure-sensitive adhesive according to claim 5.   It is a manufacturing method of an adhesive sheet, Comprising: The adhesive resin layer obtained by apply | coating the acrylic resin composition in any one of Claims 1-4 to a base material or a release sheet with a film thickness of 100 micrometers or more, and making it dry. A method for producing a pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer after drying has a thickness of 50 μm or more.