WO2016047268A1

WO2016047268A1 - Active energy ray-curable adhesive composition and adhesive sheet

Info

Publication number: WO2016047268A1
Application number: PCT/JP2015/071676
Authority: WO
Inventors: 洋平石地
Original assignee: 富士フイルム株式会社
Priority date: 2014-09-26
Filing date: 2015-07-30
Publication date: 2016-03-31
Also published as: JPWO2016047268A1; JP6312841B2

Abstract

This active energy ray-curable adhesive composition contains: a compound represented by general formula (I); a polyfunctional urethane (meth)acrylate having two or more (meth)acryloyl groups in each molecule; and a compound other than a polyfunctional urethane (meth)acrylate, which has an ethylenically unsaturated group.

Description

Active energy ray-curable pressure-sensitive adhesive composition, pressure-sensitive adhesive sheet

The present invention relates to an active energy ray-curable pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet.

Urethane (meth) acrylate is known as an active energy ray-curable resin, and its field of use has been increasing in recent years. For example, it is also used for adhesive applications.
Specifically, in Patent Document 1, active energy ray curing containing a polyisocyanate derivative (corresponding to urethane (meth) acrylate) obtained by reacting predetermined components and an ethylenically unsaturated monomer. A mold adhesive composition is disclosed. In the above composition, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (manufactured by Ciba Specialty Chemicals Co., Ltd.) was used as a photopolymerization initiator. "Irgacure 2959") is used.

JP 2003-183615 A

The pressure-sensitive adhesive sheet formed from the active energy ray-curable pressure-sensitive adhesive composition is required to exhibit excellent adhesion to the adherend. Further, since the pressure-sensitive adhesive sheet may be used after being left for a long period of time, it is also required to exhibit excellent adhesiveness even after being left in a wet and heat environment. That is, adhesive stability over time is also required.
The present inventors have studied the characteristics of a pressure-sensitive adhesive sheet formed using an active energy ray-curable pressure-sensitive adhesive composition containing urethane (meth) acrylate and Irgacure 2959 as described in Patent Document 1. As a result, in particular, the adhesive stability over time did not meet the level required recently, and further improvements were required.
Moreover, when the usage-amount of Irgacure 2959 was increased in order to improve the reactivity of urethane (meth) acrylate, there also existed a problem that a photoinitiator did not melt | dissolve in a composition.

In view of the above circumstances, the present invention is capable of forming a pressure-sensitive adhesive sheet that exhibits excellent adhesiveness and that suppresses deterioration of adhesiveness even after being left in a moist heat environment. It aims at providing the suppressed active energy ray hardening-type adhesive composition.
Another object of the present invention is to provide a pressure-sensitive adhesive sheet formed using the active energy ray-curable pressure-sensitive adhesive composition.

As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by using a predetermined photopolymerization initiator, and have reached the present invention.
That is, the present inventors have found that the above problem can be solved by the following configuration.

(1) a compound represented by the following general formula (I);
A polyfunctional urethane (meth) acrylate having two or more (meth) acryloyl groups in one molecule;
An active energy ray-curable pressure-sensitive adhesive composition comprising a compound having an ethylenically unsaturated group other than polyfunctional urethane (meth) acrylate.

In general formula (I), V ¹ , V ² , V ³ and V ⁴ each independently represent a hydrogen atom or a substituent. n represents an integer of 1 to 5.
(2) The active energy ray-curable pressure-sensitive adhesive composition according to (1), wherein n is 1 or 2. (3) The active energy ray-curable pressure-sensitive adhesive composition according to (1) or (2), wherein n is 1.
(4) The content of the polyfunctional urethane (meth) acrylate is 5 to 40% by mass with respect to the total solid mass in the active energy ray-curable pressure-sensitive adhesive composition, (1) to (3) The active energy ray hardening-type adhesive composition in any one.
(5) The active energy ray-curable pressure-sensitive adhesive composition according to any one of (1) to (4), wherein the number of (meth) acryloyl groups is 2 to 4.
(6) The activity according to any one of (1) to (5), wherein the mass ratio A between the polyfunctional urethane (meth) acrylate and the compound represented by the general formula (I) is 3.0 to 10. Energy ray-curable pressure-sensitive adhesive composition. In addition, mass ratio A represents the mass of the compound represented by the mass of polyfunctional urethane (meth) acrylate / general formula (I).
(7) The active energy ray-curable pressure-sensitive adhesive composition according to any one of (1) to (6), wherein the number of ethylenically unsaturated groups is 1 to 2.
(8) The compound according to any one of (1) to (7), wherein the compound having an ethylenically unsaturated group includes a compound having an ethylenically unsaturated group having a glass transition temperature (Tg) of the homopolymer of 0 ° C. or lower. Active energy ray-curable pressure-sensitive adhesive composition.
(9) The active energy ray according to any one of (1) to (8), wherein the polyfunctional urethane (meth) acrylate and the compound having an ethylenically unsaturated group have a mass ratio B of 0.25 to 1.0. A curable adhesive composition. The mass ratio B represents the mass of the polyfunctional urethane (meth) acrylate / the compound having an ethylenically unsaturated group.
(10) A pressure-sensitive adhesive sheet obtained by irradiating an active energy ray-curable pressure-sensitive adhesive composition according to any one of (1) to (9) with active energy rays.

According to the present invention, an adhesive sheet exhibiting excellent adhesiveness and capable of forming a pressure-sensitive adhesive sheet in which deterioration of adhesiveness is suppressed even after being left in a moist and heat environment, the activity in which precipitation of insoluble matter is suppressed is suppressed. An energy ray-curable pressure-sensitive adhesive composition can be provided.
Moreover, according to this invention, the adhesive sheet formed using an active energy ray hardening-type adhesive composition can also be provided.

It is sectional drawing of the evaluation sample used by level | step difference followable | trackability evaluation.

Below, an active energy ray hardening-type adhesive composition etc. are demonstrated.
In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Moreover, in this specification, when a component contains 2 or more types of compounds, content of the said component refers to total content.
One feature of the active energy ray-curable pressure-sensitive adhesive composition of the present invention is that a compound represented by the general formula (I) is used. As will be described later, the compound represented by the general formula (I) functions as a photopolymerization initiator. Irgacure 2959 used in Patent Document 1 does not necessarily have sufficient solubility in polyfunctional urethane (meth) acrylate or the like, and as a result, does not dissolve when added at a high concentration, and precipitates as an insoluble matter. Crystallized and precipitated. On the other hand, since the compound represented by the general formula (I) used in the present invention exhibits excellent compatibility with the polyfunctional urethane (meth) acrylate, it can be used at a high addition amount, and insoluble matter is precipitated. Is suppressed. Therefore, the reactivity of polyfunctional urethane (meth) acrylate improves, components, such as a monomer residue, reduce, As a result, the outstanding adhesiveness is implement | achieved. Further, after the compound represented by the general formula (I) is exposed to light and decomposed, the residue contains components derived from an ethyleneoxy structure. These components are contained in the polyfunctional urethane (meth) acrylate. It is thought that it can react with an isocyanate residue. It is considered that the residue generated after exposure of the conventionally used Irgacure 2959 bleeds out to the surface of the pressure-sensitive adhesive sheet in a moist heat environment, and these components are considered to have reduced adhesiveness. On the other hand, as described above, the residue generated from the compound represented by the general formula (I) reacts with the isocyanate residue in the polyfunctional urethane (meth) acrylate, and is fixed in the adhesive sheet. It is considered that the bleed out as described above is suppressed, and as a result, the decrease in adhesiveness is suppressed even after the pressure-sensitive adhesive sheet is left in a wet and heat environment.

The active energy ray-curable pressure-sensitive adhesive composition of the present invention (hereinafter also simply referred to as “composition”) includes a compound represented by the following general formula (I), a polyfunctional urethane (meth) acrylate, and ethylene. And a compound having a polymerizable unsaturated group.
Hereinafter, first, components contained in the composition will be described in detail.

<(A): Compound represented by general formula (I)>
The composition includes a compound represented by the general formula (I). This compound functions as a so-called photopolymerization initiator.

In general formula (I), V ¹ , V ² , V ³ , and V ⁴ each independently represent a hydrogen atom or a substituent. The type of the substituent is not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkoxy group, a hydroxy group, an alkylthio group, a mercapto group, an acyl group, and an amino group.
As the halogen atom, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom are preferable, a chlorine atom and a bromine atom are more preferable, and a chlorine atom is particularly preferable.
The number of carbon atoms contained in the alkyl group is not particularly limited, but is preferably 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. The alkyl group may be a straight chain alkyl group or a branched chain alkyl group. Moreover, the alkyl group may have an alicyclic structure. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, and cyclohexyl group. And a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are preferable.
The number of carbon atoms contained in the alkoxy group is not particularly limited, but is preferably 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. The alkoxy group may be a linear alkoxy group or a branched alkoxy group. Moreover, the alkoxy group may have an alicyclic structure. Specific examples of the alkoxy group include methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, n-butoxy group, s-butoxy group, t-butoxy group, n-pentyloxy group, and n-hexyloxy group. And a cyclohexyloxy group, and a methoxy group, an ethoxy group, an n-propyloxy group, and an isopropyloxy group are preferable.
The number of carbon atoms contained in the alkylthio group is not particularly limited, but is preferably 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms. The alkylthio group may be a linear alkylthio group or a branched alkylthio group. Moreover, the alkylthio group may have an alicyclic structure. Specific examples of the alkylthio group include methylthio group, ethylthio group, n-propylthio group, isopropylthio group, n-butylthio group, s-butylthio group, t-butylthio group, n-pentylthio group, n-hexylthio group, cyclohexylthio group. And a methylthio group, an ethylthio group, an n-propylthio group, and an isopropylthio group are preferable.
The number of carbon atoms contained in the acyl group is not particularly limited, but is preferably 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. The acyl group may be a straight chain acyl group or a branched chain acyl group. Specific examples of the acyl group include a formyl group, an acetyl group, an ethylacyl group, an n-propylacyl group, and an isopropylacyl group, and a formyl group, an acetyl group, and an ethylacyl group are preferable.

Among them, the point that the pressure-sensitive adhesive sheet is more excellent in adhesiveness and / or the point that the decrease in the pressure-sensitive adhesive sheet in a wet heat environment is further suppressed (hereinafter simply referred to as “the point where the effect of the present invention is more excellent”). V ¹ to V ⁴ are each independently preferably a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or an alkylthio group, more preferably a hydrogen atom, an alkoxy group or an alkylthio group, and even more preferably a hydrogen atom. .
Further, as a preferable form of the compound represented by the general formula (I), a form in which two or more (preferably three or more, more preferably four) of V ¹ to V ⁴ are hydrogen atoms can be mentioned. .

In general formula (I), n represents an integer of 1 to 5. Among these, 1 to 3 is preferable, 1 to 2 is more preferable, and 1 is more preferable in that the effect of the present invention is more excellent.

Hereinafter, although the specific example (exemplary compound) of the compound represented by general formula (I) is shown, the compound represented by general formula (I) is not limited to these.

One of the preferred embodiments is that the compound represented by the general formula (I) is liquid at 23 ° C.
The compound represented by the general formula (I) can be synthesized, for example, according to the method described in paragraphs 0067 to 0071 and 0112 to 0115 of JP-A No. 2000-186242.

The content of the compound represented by the general formula (I) in the composition is not particularly limited, but is 0.3 to 10 with respect to the total solid mass in the composition in that the effect of the present invention is more excellent. 0.0 mass% is preferable, 0.5 to 7.0 mass% is more preferable, and 0.8 to 5.0 mass% is still more preferable.
In addition, solid content in a composition intends the component which comprises an adhesive sheet, and volatile components, such as a solvent, are not contained.
In addition, only 1 type may be used for the compound represented by general formula (I), and 2 or more types may be used together.

<(B): Multifunctional urethane (meth) acrylate>
The composition includes polyfunctional urethane (meth) acrylate. The polyfunctional urethane (meth) acrylate is a compound having two or more (meth) acryloyl groups in one molecule and having a urethane bond (—NHCOO—). In addition, polyfunctional urethane (meth) acrylate is the concept containing polyfunctional urethane acrylate and polyfunctional urethane methacrylate. The (meth) acryloyl group is a concept including an acryloyl group and a methacryloyl group.
The number of (meth) acryloyl groups contained in the polyfunctional urethane (meth) acrylate may be two or more, but 2 to 8 is preferable and 2 to 6 is more preferable in terms of more excellent effects of the present invention. Preferably, 2 to 4 are more preferable from the viewpoint that the step following property of the pressure-sensitive adhesive sheet is more excellent.

As an example of the polyfunctional urethane (meth) acrylate, a polyisocyanate compound and a hydroxyl group-containing (meth) acrylate compound are reacted.
The polyisocyanate compound is not particularly limited, and examples thereof include aromatic, aliphatic, and alicyclic polyisocyanates. Among them, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, polyisocyanate, and the like. Phenylmethane polyisocyanate, modified diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) ) Cyclohexane, phenylene diisocyanate, lysine diisocyanate, lysine triisocyanate And polyisocyanates such as naphthalene diisocyanate, trimer compounds or multimeric compounds of these polyisocyanates, burette type polyisocyanates, water-dispersed polyisocyanates (for example, “Aquanate 100”, “Aqua Nate 110 ”,“ Aquanate 200 ”,“ Aquanate 210 ”, etc.), or the reaction products of these polyisocyanates and polyols. These can be used alone or in combination of two or more.

Examples of the polyol that can react with the polyisocyanate include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, and 1,4-butanediol. , Polybutylene glycol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol, hydrogenated bisphenol A, polycaprolactone, trimethylolethane, trimethylolpropane, polytrimethylolpropane, pentaerythritol, polypentaerythritol, sorbitol, Mannitol, glycerin, polyglycerin, polytetramethylene glycol, polyether Le polyols, polyester polyols, caprolactone-modified polyols, polyolefin polyols, polybutadiene polyols and the like.

Examples of the hydroxyl group-containing (meth) acrylate compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2 -Hydroxyethylacryloyl phosphate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, caprolactone modified 2-hydroxyethyl (meth) acrylate , Pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone-modified dipentaerythritol penta (meth) acrylate, caprolactone-modified penta Risuri Tall tri (meth) acrylate, ethylene oxide-modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate. These can be used alone or in combination of two or more.

Examples of commercially available products of polyfunctional urethane (meth) acrylate include bifunctional urethane (meth) acrylate compounds such as U-108A, UA-112P, UA-5201, UA-512, UA-412A, UA-4200, UA-4400, UA-340P, UA-2235PE, UA-160TM, UA-122P, UA-512, UA-W2, UA-7000, UA-7100 (above, trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.); CN962, CN963, CN964, CN965, CN980, CN981, CN982, CN982, CN996, CN9001, CN9002, CN9788, CN9873, CN978, CN9782, CN9783 (above, trade name, manufactured by Sartomer Japan, Inc.); M-1100, M- 1200, M-12 0, M-1310, M-1600 (trade names, manufactured by Toagosei Chemical Industry Co., Ltd.); UN-9000PEP, UN-9200A, UN-7600, UN-
333, UN-1255, UN-6060PTM, UN-6060P, SH-500B (above, trade name, manufactured by Negami Kogyo); AH-600, AT-600 (above, trade name, manufactured by Kyoeisha Chemical Co., Ltd.); 284, Evecril 402, Evekril 8402, Evekril 8807, Evekril 9270 (above, trade name, manufactured by Daicel Cytec); and the like.
Examples of the trifunctional urethane (meth) acrylate include, for example, CN929, CN944B85, CN989, CN9008 (above, trade name, manufactured by Sartomer Japan Co., Ltd.); 294 / 25HD, Everkril 4820 (above, trade name, manufactured by Daicel-Cytec);
Examples of the tetra- or more functional urethane (meth) acrylate compound include U-6HA, U-6LPA, U-6H, U-15HA, UA-32P, U-324A, UA-7200 (above, trade name, Shin-Nakamura) CN968, CN9006, CN9010 (trade names, manufactured by Sartomer Japan, Inc.); UN-3320HA, UN-3320HB, UN-3320HC, UN-3320HS, UN-904, UN-901T, UN -905, UN-952 (above, trade name, manufactured by Negami Kogyo Co., Ltd.); Can be mentioned.

The content of the polyfunctional urethane (meth) acrylate in the composition is not particularly limited, but is 2.5 to 50% by mass with respect to the total solid content in the composition in that the effect of the present invention is more excellent. Preferably, it is 5 to 40% by mass, more preferably 15 to 35% by mass.
In addition, only 1 type may be used for polyfunctional urethane (meth) acrylate, and 2 or more types may be used together.
Mass ratio A (mass of polyfunctional urethane (meth) acrylate / mass of compound represented by general formula (I)) between the polyfunctional urethane (meth) acrylate and the compound represented by general formula (I) is particularly limited. However, 0.5 or more is preferable, 3.0 or more is more preferable, 12 or less is preferable, 10 or less is more preferable, and 8 or less is more preferable in that the effect of the present invention is more excellent.

<(C): Compound having an ethylenically unsaturated group>
The composition contains a compound having an ethylenically unsaturated group other than the polyfunctional urethane (meth) acrylate. That is, the composition includes a compound having an ethylenically unsaturated group, which is different from the polyfunctional urethane (meth) acrylate.
Examples of the ethylenically unsaturated group contained in this compound include a vinyl group, a (meth) acryloyl group, and a (meth) acrylamide group. The (meth) acrylamide group is a concept including an acrylamide group and a methacrylamide group.
The number of ethylenically unsaturated groups contained in this compound is not particularly limited, but is usually 1 or more, preferably 1 to 4 and more preferably 1 to 2 in terms of more excellent effects of the present invention. .

Examples of the compound having an ethylenically unsaturated group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, isobutyl acrylate, t-butyl acrylate, isooctyl acrylate, 2-methoxyethyl acrylate, methoxy Triethylene glycol acrylate, 2-ethoxyethyl acrylate, 3-methoxybutyl acrylate, ethoxyethoxyethyl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydipropylene glycol acrylate, dipropylene glycol acrylate, β-carboxyl ethyl acrylate, ethyl diglycol Acrylate, trimethylolpropane formal monoacrylate DOO, imide acrylate, isoamyl acrylate, ethoxylated succinic acid acrylate, trifluoroethyl acrylate, .omega.-carboxypolycaprolactone monoacrylate, compounds of monofunctional, such as N- vinylformamide;
Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethoxylated 1,6-hexanediol diacrylate, neopentyl glycol di (Meth) acrylate, polypropylene glycol diacrylate, 1,4-butanediol di (meth) acrylate, 1,9-nonanediol diacrylate, tetraethylene glycol diacrylate, 2-n-butyl-2-ethyl-1,3 -Propanediol diacrylate, hydroxypivalate neopentyl glycol diacrylate, 1,3-butylene glycol di (meth) acrylate, ethoxylated tripropylene glycol diacrylate, Opentyl glycol modified trimethylolpropane diacrylate, stearic acid modified pentaerythritol diacrylate, neopentyl glycol oligoacrylate, 1,4-butanediol oligoacrylate, 1,6-hexanediol oligoacrylate, ethoxylated neopentyl glycol di (meta ) Acrylate, propoxylated neopentyl glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, bisphenol A diacrylate, dimethylol-tricyclodecane diacrylate, propoxylated bisphenol A di (meth) acrylate, ethoxylated bisphenol A di (meth) acrylate, bisphenol F diacrylate, ethoxylated bisphenol F diacrylate, propo Deer bisphenol F diacrylate, cyclohexanedimethanol di (meth) acrylate, dimethylol dicyclopentane diacrylate, isocyanuric acid diacrylate, difunctional compounds such as propoxylated isocyanuric acid diacrylate.

As a preferred embodiment of the compound having an ethylenically unsaturated group, the glass transition temperature (Tg) of the homopolymer (glass transition temperature when forming the homopolymer) is 0 ° C. or less (preferably −70 to − 30 ° C) having an ethylenically unsaturated group. When such a compound is used, it is easy to adjust the hardness of the pressure-sensitive adhesive sheet and to easily control the adhesiveness. The glass transition temperature of the homopolymer is described in J. Brandrup, E .; H. Immergut, Polymer Handbook, 2nd Ed. , J .; Wiley, New York 1975, photocuring technology data book (Technonet Books, Inc.), POLYMER HANDBOOK (Polymer Handbook) 3rd edition, Chapter 6, page 209, and the like.
In addition, only 1 type may be used for the compound which has an ethylenically unsaturated group, and 2 or more types may be used together.
In the case of using two types of compounds having an ethylenically unsaturated group, the compound A having an ethylenically unsaturated group having a glass transition temperature (Tg) of the homopolymer of A ° C. and the glass transition temperature (Tg) of the homopolymer In the relationship with the compound B having an ethylenically unsaturated group in which B is B ° C, it is preferable that A ° C and B ° C are different from each other by 40 ° C or more in that the adhesiveness of the pressure-sensitive adhesive sheet is easily controlled. More preferably, the difference is more preferably 75 ° C. or more. The upper limit of the difference between A ° C and B ° C is not particularly limited, but is preferably within 180 ° C.
When a compound having two or more types of ethylenically unsaturated groups is used, a compound having one ethylenically unsaturated group (monofunctional compound) and a compound having two or more ethylenically unsaturated groups (multiple compounds) A functional compound) may be used in combination.

The content of the compound having an ethylenically unsaturated group in the composition is not particularly limited, but is 2.5 to 95% with respect to the total solid content in the composition in that the effect of the present invention is more excellent. It is preferably 10 to 70% by mass, more preferably 20 to 65% by mass.
The mass ratio B (mass of polyfunctional urethane (meth) acrylate / mass of compound having ethylenically unsaturated groups) between the polyfunctional urethane (meth) acrylate and the compound having an ethylenically unsaturated group is not particularly limited. 0.05 or more are preferable, 0.25 or more are more preferable, 1.5 or less are preferable, and 1.0 or less are more preferable at the point which the effect of invention is more excellent.

<Other ingredients>
The composition may contain components other than the components described above (compound represented by the general formula (I), polyfunctional urethane (meth) acrylate, compound having an ethylenically unsaturated group).
For example, the composition may contain a binder. As the binder, for example, a so-called polymer binder is used. The type of binder is not particularly limited. For example, acrylic resin, styrene resin, vinyl resin, polyolefin resin, polyester resin, polyurethane resin, polyamide resin, polycarbonate resin, polydiene resin, epoxy resin , Silicone resins, cellulose polymers, and chitosan polymers.
When a binder is contained in the composition, the content of the binder is not particularly limited, but is preferably 10 to 70% with respect to the total solid content in the composition in terms of more excellent effects of the present invention. It is more preferably from 60 to 60% by mass, and further preferably from 30 to 60% by mass.
In addition, only 1 type may be used for a binder and it may be used in combination of 2 or more types.

In addition to the above, the composition includes a surface lubricant, a leveling agent, an antioxidant, a corrosion inhibitor, a light stabilizer, an ultraviolet absorber, a polymerization inhibitor, and a silane coupling as long as the effects of the present invention are not impaired. It can be added as appropriate according to the use for which various conventionally known additives such as an agent, an inorganic or organic filler, a powder such as a metal powder and a pigment, a particle, and a foil are used.

The method for preparing the composition is not particularly limited, and a known method can be adopted. For example, after mixing each said component, it can prepare by stirring by a well-known means.

<Method for producing adhesive sheet>
An adhesive sheet can be manufactured by irradiating the said composition with an active energy ray.
The method for producing the pressure-sensitive adhesive sheet is not particularly limited, and a known method can be adopted.For example, the composition is applied on a substrate to form a coating film, and the coating film is irradiated with active energy rays and cured. And a method for producing an adhesive sheet.
Hereinafter, the above method will be described in detail.

Although the kind in particular of base material to be used is not restrict | limited, So-called release film (release sheet, release film) is mentioned preferably from the point which bonds an adhesive sheet to another member. Examples of the release film include a film whose surface is treated with a silicone-based release agent and other release agents, and a film that itself has release properties. Moreover, as a material which comprises a release film, polyolefin, such as a polypropylene and polyethylene, polyester, nylon, polyvinyl chloride, etc. are mentioned, for example.
As a method for applying the composition onto the substrate, a known method can be employed, and examples thereof include a coating method using a gravure coater, comma coater, bar coater, knife coater, die coater, roll coater and the like.
The average thickness of the coating film formed by the above application is not particularly limited and is adjusted according to the average thickness of the pressure-sensitive adhesive sheet to be produced, but is usually 5 to 2500 μm (preferably 10 to 500 μm) in many cases. The average thickness is a value obtained by measuring the thicknesses of 10 arbitrary points of the coating film and arithmetically averaging them.

In addition, after forming the said coating film, you may implement a drying process as needed. By carrying out the drying treatment, volatile components (such as a solvent) contained in the coating film can be removed. The method for the drying treatment is not particularly limited, but a method for performing a heat treatment at a temperature (for example, 60 to 100 ° C.) at which polymerization of the polyfunctional urethane (meth) acrylate etc. does not proceed, a method for carrying out an air drying treatment, etc. Is mentioned.

Next, an active energy ray is irradiated with respect to the obtained coating film.
The active energy ray may be appropriately set according to the purpose, and includes rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, electromagnetic waves such as X-rays and γ rays, electron beams, proton rays, neutron rays, and the like. Ultraviolet rays are preferable from the viewpoints of curing speed, availability of an irradiation device, price, and the like.
For the ultraviolet irradiation, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, an electrodeless discharge lamp, an ultraviolet LED, or the like that emits light in a wavelength range of 150 to 450 nm can be used.
Although the illuminance of the light irradiation is performed on the coating film is not particularly limited, in terms of properties and productivity of the balance of pressure-sensitive adhesive sheet obtained is preferably ^{10 ~ 2000mW / cm 2, 100} ~ 1000mW / cm 2 Gayori preferable.
Exposure amount in the irradiation is not particularly limited, in terms of properties and productivity of the balance of pressure-sensitive adhesive sheet obtained is preferably 2000 mJ / cm ² or less, more preferably 1750mJ / cm ² or less, 1500 mJ / cm ² or less Is more preferable. Although a minimum in particular is not restrict | limited, 500 mJ / cm < ² > or more is preferable from the point of the characteristic of an adhesive sheet.
The atmosphere at the time of light irradiation is not particularly limited, and may be in the air or in an inert gas atmosphere.
In addition, when irradiating an active energy ray, you may implement in the state which pinched | interposed the coating film with the release film.

<Adhesive sheet>
The pressure-sensitive adhesive sheet obtained by the above procedure exhibits excellent pressure-sensitive adhesiveness, and the deterioration of the pressure-sensitive adhesive property is suppressed even in a moist heat environment. The pressure-sensitive adhesive sheet also exhibits excellent step following ability.
The average thickness of the pressure-sensitive adhesive sheet is not particularly limited, but is usually preferably 5 to 2500 μm, more preferably 10 to 500 μm, and further preferably 50 to 250 μm. The said average thickness is the value which measured the thickness of arbitrary 10 points | pieces of an adhesive sheet, and arithmetically averaged them.
The pressure-sensitive adhesive sheet is preferably optically transparent. That is, it is preferably a transparent adhesive sheet. Optically transparent means that the total light transmittance is 85% or more, preferably 90% or more, and more preferably 95% or more.
A release film may be bonded to the surface of the obtained pressure-sensitive adhesive sheet as necessary.

Although the gel fraction of the adhesive sheet formed using the said composition is not restrict | limited in particular, 30% or more is preferable and 35% or more is more preferable at the point which the effect of this invention is more excellent.
The measuring method of the gel fraction of an adhesive sheet is as follows.
That is, the pressure-sensitive adhesive sheet (0.2 g) is immersed in a predetermined solvent (30 g) and allowed to stand for 24 hours while being kept at 40 ° C. Thereby, components other than the gel component in an adhesive sheet melt | dissolve in a solvent. And the immersed adhesive sheet is taken out, dried, and its mass is measured. And the gel fraction (%) in an adhesive sheet is computed from the following formula | equation.
“Gel fraction” = (mass of adhesive sheet after immersion) / (mass of adhesive sheet before immersion) × 100 (%)
In addition, as a predetermined | prescribed solvent, the solvent whose solubility of the used polyfunctional urethane (meth) acrylate and the compound which has an ethylenically unsaturated group is 1 mass% or more is used. Here, the solubility (mass%) is intended to mean an amount in which the above components are uniformly dissolved in the solvent. For example, when 100 g of the solvent dissolves 1 g of the polyfunctional urethane (meth) acrylate uniformly, the solubility (% By mass) is defined as 1% by mass. Examples of such a solvent include tetrahydrofuran, toluene, hexane, ethyl acetate, and the like. In the examples described later, ethyl acetate is used.

The pressure-sensitive adhesive sheet of the present invention can be applied to various applications, for example, touch panel applications, and in particular, can be suitably used for the production of touch panels (particularly, capacitive touch panels).

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

<Synthesis of photopolymerization initiator>
(Synthesis of Intermediate (2) -1)
97.2 g (0.95 mol) of acetic anhydride was added dropwise to 170.0 g of phenyldiglycol (PhDG, manufactured by Nippon Emulsifier) (0.93 mol) heated to 90 ° C., and the mixture was heated and stirred at 120 ° C. for 6 hours. Thereafter, the mixture was concentrated under reduced pressure to obtain 204.4 g of intermediate (2) -1 (yield 98%). The structure of the obtained intermediate (2) -1 was measured by using a nuclear magnetic resonance apparatus ( ¹ H-NMR) (solvent: CDCl ₃ ), and the compound of the following formula (2) -1 It was confirmed that. The measurement data of ¹ H-NMR is shown below.

¹ H-NMR (CDCl ₃ )
δ: 2.10 (3H, s), 3.78 (2H, m), 3.87 (2H, m), 4.15 (2H, m), 4.26 (2H, m), 6.90 -6.98 (3H, m), 7.25-7.32 (2H, m)

(Synthesis of Intermediate (3) -1)
To 270 mL of o-dichlorobenzene (DCB) (2.39 mol), 120.0 g of aluminum (III) chloride (0.90 mol) was added and cooled to 0 ° C. To this, 44.26 mL of 2-bromoisobutyric acid bromide (0.36 mol) was added dropwise and stirred for 15 minutes. Thereafter, 67.28 g of intermediate (2) -1 (0.30 mol) was added dropwise over 30 minutes while maintaining the temperature of the reaction solution at 0 ° C. The reaction solution after the dropping was returned to room temperature (22 ° C.) and stirred for 2 hours. Thereafter, the reaction solution was added in several portions to 300 mL of water cooled to 5 ° C. The organic phase was washed twice with 300 ml of water, further washed with 135 mL of sodium bicarbonate solution and 135 mL of saturated brine, added with 300 mL of water, and concentrated azeotropically under reduced pressure to give intermediate (3) -1 110.8 g was obtained (yield 95%). The structure of the obtained intermediate (3) -1 was confirmed to be a compound of the following formula (3) -1 by measurement using a nuclear magnetic resonance apparatus (solvent: CDCl ₃ ). It was. The measurement data of ¹ H-NMR is shown below.

¹ H-NMR (CDCl ₃ )
δ: 2.04 (6H, s), 2.08 (3H, s), 3.79 (2H, m), 3.85 (2H, m), 4.21 (2H, m), 4.26 (2H, m), 6.94 (2H, d), 8.21 (2H, d)

(Synthesis of Compound (I) -1)
100.0 g of compound (3) -1 (0.27 mol) was dissolved in 200 mL of isopropyl alcohol, and 214 g of a 25% by mass aqueous sodium hydroxide solution was added dropwise thereto and stirred for 2 hours. Thereafter, stirring was stopped, and the organic phase was washed twice with a saturated saline solution and then neutralized with hydrochloric acid. After the organic phase was concentrated under reduced pressure, 72 mL of methyl ethyl ketone was added, and the precipitated salt was filtered. The filtrate was concentrated under reduced pressure, 72 mL of water was added, and azeotropic concentration was performed under reduced pressure to obtain 56.8 g of Compound (I) -1 (yield 87%).

¹ H-NMR (CDCl ₃ )
δ: 1.64 (6H, s), 3.69 (2H, m), 3.78 (2H, m), 3.91 (2H, m), 4.22 (2H, m), 4.26 (1H, s), 6.97 (2H, d), 8.06 (2H, d)

Compound (I) -2, Compound (I) -4, and Compound (C) -1 were synthesized as compounds represented by general formula (I) with reference to the above procedure. Moreover, as shown in Table 2 described later, “Irgacure 2959” (Irg2959) (trade name, manufactured by BASF), which is a commercial product, was used as a compound used in the comparative example. In addition, Irg2959 corresponds to the compound of n = 0 in general formula (I).

<Examples 1 to 27, Comparative Examples 1 to 8>
(Preparation of active energy ray-curable pressure-sensitive adhesive composition)
The components shown in Table 2 below were mixed in the blending amounts (parts by mass) shown in Table 2 below and stirred to obtain each active energy ray-curable pressure-sensitive adhesive composition.
For example, the active energy ray-curable pressure-sensitive adhesive composition of Example 1 includes 30 parts by mass of U-6LPA (hexafunctional: Shin-Nakamura Chemical Co., Ltd.), which is a polyfunctional urethane (meth) acrylate, and tetraethylene glycol diacrylate ( A composition obtained by mixing 20 parts by mass of TEGDA), 45 parts by mass of methoxyethyl acrylate (MEA), and 5 parts by mass of the compound represented by formula (I) -1.

(Preparation of adhesive sheet)
The obtained active energy ray-curable pressure-sensitive adhesive composition was coated on the entire surface of a release PET (released polyethylene terephthalate film (trade name: Diafoil): manufactured by Mitsubishi Plastics) to form a coating film (precursor film). ), And another release PET was stuck on the coating film to form a coating film sandwiched between the release PET. Next, the formed coating film is irradiated with a fusion UV lamp (D bulb) under the conditions of illuminance (200 mW / cm ² ) and exposure dose (1000 mJ / cm ² ), and cured to release PET (polyethylene). An adhesive film containing an adhesive sheet (average thickness: 100 μm) sandwiched between terephthalates) and release PET was obtained.

The gel fraction (%) in the pressure-sensitive adhesive sheets obtained in each Example and Comparative Example was measured by the method described above. The results are summarized in Table 2.

<Evaluation of adhesive strength Fr (Evaluation of initial adhesiveness)>
Each obtained adhesive film was cut out to 2.5 cm × 5 cm, the release PET was peeled off, and a sample was prepared by sticking one side of the cut out adhesive sheet to a glass substrate and the other side to a Kapton film. Subsequently, one end of the Kapton film (2.5 cm width side of the adhesive sheet) was gripped using an autograph manufactured by Shimadzu Corporation, and a 180-degree peel test (tensile speed of 300 cm / min) was performed. The adhesive sheet and the glass substrate The average value of the test force was measured, and this value was defined as the adhesive strength Fr (N / mm). The results are shown in Table 2. Practically, the adhesive strength is preferably 0.45 N / mm or more.

<Evaluation of adhesive strength Th (evaluation after leaving in wet heat environment)>
The obtained adhesive film was exposed to high-temperature steam for 10 days at 85 ° C./85RH. Then, using the obtained adhesive film, adhesive force Th (N / mm) was measured according to the same procedure as in the above <Evaluation of adhesive force Fr (initial adhesive evaluation)>. The results are shown in Table 2.
Table 2 shows the difference between the adhesive strength Fr and the adhesive strength Th (Δ = adhesive strength Fr−adhesive strength Th). In practice, Δ is preferably 0.10 N / mm or less.

<Evaluation of step following ability>
Each obtained adhesive film was cut into 2.5 cm × 4 cm, the release PET was peeled off, and one side of the cut out adhesive sheet was attached to a glass substrate wrapped with Kapton tape (5 mm width 35 μm thickness) A sample was prepared by attaching the surface to optical PET. Subsequently, using an autoclave, a heat press treatment was performed under the conditions of an internal temperature of 40 ° C., 5 atm, and 20 minutes to prepare a sample for a step following test.
About the produced sample, the boundary surface formed between the adhesive sheet and the Kapton tape level | step difference was observed with the Nikon optical microscope, and the boundary space | gap width was measured. More specifically, as shown in FIG. 1, the configuration of the obtained sample corresponds to an aspect in which an adhesive sheet 54 and optical PET 56 are arranged on a glass substrate 50 on which a Kapton tape 52 is pasted. As shown in FIG. 1, a gap 58 is easily generated between the glass substrate 50 and the adhesive sheet 54 at the step portion of the Kapton tape 52, and the boundary gap width is not in contact with the Kapton tape 52 and the adhesive sheet 54. A distance D on the glass substrate is intended.
Of the measured boundary gap width, the largest value of less than 20 μm is designated as “A” as having excellent step followability, and those having 20 μm or more but less than 50 μm are designated as “B” having relatively excellent step followability, A material having a thickness of 50 μm or more and less than 100 μm is not preferable, but “C” is used as a practically usable product, and a product having a thickness of 100 μm or more is “D” because it is inferior in level-step following property and has no practicality. The results are shown in Table 2.

In Table 2, “UA-6LPA (6)”, “UA-160TM (2)” and “UA-122P (2)” correspond to polyfunctional urethane (meth) acrylates manufactured by Shin-Nakamura Chemical Co., Ltd., respectively. In addition, the numerical value in () intends the number of (meth) acryloyl groups.
In Table 2, “TEGDA (2)” represents tetraethylene glycol diacrylate, “MEA (1)” represents methoxyethyl acrylate, and “BA (1)” represents butyl acrylate. The numbers in parentheses are intended for the number of ethylenically unsaturated groups. The glass transition temperature (Tg) of the homopolymer of tetraethylene glycol diacrylate is 23 ° C., the glass transition temperature (Tg) of the homopolymer of methoxyethyl acrylate is −50 ° C., and the glass of homopolymer of butyl acrylate The transition temperature (Tg) was −55 ° C.
In Table 2, “PSt” represents polystyrene (weight average molecular weight 35000), and “PMMB” represents polybutyl methacrylate (weight average molecular weight 12000).
Numerical values in each component column in Table 2 represent parts by mass.
In Table 2, “A value” in the “Parameter” column represents a mass ratio A (mass of polyfunctional urethane (meth) acrylate / mass of compound represented by formula (I)). “B value” represents a mass ratio B (mass of polyfunctional urethane (meth) acrylate / mass of compound having an ethylenically unsaturated group).
In Table 2, in Comparative Examples 1 and 5 to 8, various evaluations were not performed because the photopolymerization initiator was not dissolved in the composition and there was an insoluble content.

As shown in Table 2, the pressure-sensitive adhesive sheet obtained from the composition of the present invention is excellent in pressure-sensitive adhesiveness, and a decrease in the pressure-sensitive adhesive property is suppressed even after being left in a wet and heat environment, and a desired effect can be obtained. confirmed. Moreover, insoluble matter was not confirmed in the composition used in the Example.
In particular, from the comparison of Examples 2, 5 and 18-2, it was confirmed that the step following ability was more excellent when the functional number of the polyfunctional urethane (meth) acrylate (the number of (meth) acryloyl groups) was 4 or less. It was.
Moreover, when n in general formula (I) is 1 or 2 (especially 1) from the comparison of Example 7, 26, and 27, adhesive force is more excellent, (DELTA) is smaller, and adhesion in wet heat environment It was confirmed that the force drop was smaller.
Further, from the comparison of Examples 7 to 9 (or Examples 19 to 22), when the mass ratio A is 3.0 to 10, Δ is smaller, and the decrease in the adhesive strength in a moist heat environment is smaller. confirmed.
Further, in comparison with Examples 24 and 25, when the mass ratio B is 1.0 or less, the step following ability is more excellent, and from the comparison of all Examples, the step following ability is “A”. It was confirmed that it is required to satisfy that the mass ratio B is at least 0.25.
On the other hand, as described above, in Comparative Examples 1 and 5 to 8, the photopolymerization initiator (Irg2959) was not dissolved in the composition, and various evaluations could not be performed. In Comparative Examples 2 to 4 in which the compound represented by the general formula (I) was not used, the adhesive force Fr was inferior and / or Δ was large, and the desired effect was not obtained. In addition, in Comparative Examples 2 to 3 using Irg2959 described in Patent Document 1, a desired effect was not obtained.

50 Glass substrate 52 Kapton tape 54 Adhesive sheet 56 Optical PET
58 Air gap

Claims

A compound represented by the general formula (I);
A polyfunctional urethane (meth) acrylate having two or more (meth) acryloyl groups in one molecule;
An active energy ray-curable pressure-sensitive adhesive composition comprising an ethylenically unsaturated group compound other than the polyfunctional urethane (meth) acrylate.

In general formula (I), V 1 , V 2 , V 3 and V 4 each independently represent a hydrogen atom or a substituent, and n represents an integer of 1 to 5.
The active energy ray-curable pressure-sensitive adhesive composition according to claim 1, wherein n is 1 or 2.
The active energy ray-curable pressure-sensitive adhesive composition according to claim 1 or 2, wherein n is 1.
The content of the polyfunctional urethane (meth) acrylate is 5 to 40% by mass with respect to the total solid content in the active energy ray-curable pressure-sensitive adhesive composition. The active energy ray-curable pressure-sensitive adhesive composition according to Item.
The active energy ray-curable pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the number of the (meth) acryloyl groups is 2 to 4.
The mass ratio A between the polyfunctional urethane (meth) acrylate and the compound represented by the general formula (I) is 3.0 to 10,
The active energy ray curing according to any one of claims 1 to 5, wherein the mass ratio A represents the mass of the polyfunctional urethane (meth) acrylate / the mass of the compound represented by the general formula (I). Type pressure-sensitive adhesive composition.
The active energy ray-curable pressure-sensitive adhesive composition according to any one of claims 1 to 6, wherein the number of the ethylenically unsaturated groups is 1 to 2.
The activity according to any one of claims 1 to 7, wherein the compound having an ethylenically unsaturated group includes a compound having an ethylenically unsaturated group having a glass transition temperature (Tg) of a homopolymer of 0 ° C or lower. Energy ray-curable pressure-sensitive adhesive composition.
The mass ratio B of the polyfunctional urethane (meth) acrylate and the compound having an ethylenically unsaturated group is 0.25 to 1.0,
The active energy ray-curable adhesive according to any one of claims 1 to 8, wherein the mass ratio B represents the mass of the polyfunctional urethane (meth) acrylate / the mass of the compound having an ethylenically unsaturated group. Agent composition.
10. The pressure-sensitive adhesive sheet obtained by irradiating an active energy ray-curable pressure-sensitive adhesive composition according to any one of claims 1 to 9 with active energy rays.