JP6756993B2 - Active energy ray-curable pressure-sensitive adhesive composition, cured product and pressure-sensitive adhesive sheet - Google Patents

Description

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

In recent years, display devices such as touch panels have been used in digital information devices such as mobile phones, portable game machines, and car navigation systems. Further, in such a display device, many optical members such as a liquid crystal element, a light emitting diode element, and an organic electroluminescence element are used.

At the time of manufacturing the display device, a transparent double-sided adhesive sheet is used for the purpose of bonding the display device and the optical member or the optical members to each other. Such a double-sided adhesive sheet is required to have performance such as transparency, weather resistance, and metal corrosion prevention.

In addition, some touch panels have a decorative print on the frame portion in order to improve the design. In cosmetic printing, a step is generated between the printed portion and the non-printed portion, so that the adhesive layer of the double-sided adhesive sheet has a followability for filling the printing step (hereinafter, also referred to as "step followability"). Desired. If the step followability is insufficient, the adhesive layer may float in the vicinity of the step, which may cause light reflection loss.

On the other hand, there is a cutting step when processing the adhesive sheet, and it is necessary that the adhesive layer of the cut portion after cutting does not adhere to the blade. Further, it is also necessary that the cross section of the adhesive layer of the cut portion is not roughened. If the elastic modulus of the adhesive layer at room temperature is low, the adhesive layer of the cut portion may adhere to the punching blade after the punching process, and the cross section of the cut portion of the adhesive layer may be roughened, resulting in poor workability.

As a pressure-sensitive adhesive layer having improved step followability and flexibility, a thermosetting ultraviolet-curable pressure-sensitive adhesive composition containing a base polymer containing a methacrylic acid ester monomer and a plasticizer has been proposed (Patent Documents). 1). Further, as the pressure-sensitive adhesive sheet having improved step followability and punching workability, as the pressure-sensitive adhesive layer, a polymerizable urethane polymer (A) having ethylenically unsaturated groups at both ends of the molecule, and one at one end of the molecule. A UV-curable pressure-sensitive adhesive composition containing a polymerizable urethane polymer (B) having a hydroxyl group and one ethylenically unsaturated group at the other end and a monofunctional acrylate has been proposed (Patent Document 2). reference).

Japanese Unexamined Patent Publication No. 2015-105329 Japanese Unexamined Patent Publication No. 2012-251030

In Patent Document 1, since a plasticizer having a low softening point is used, there is a concern that the holding power may be lowered at high temperatures. Further, since a plasticizer having a low softening point is used, the elastic modulus at room temperature becomes low, the cut portion adheres to the punching blade after the punching process, and the cross section of the cut portion of the adhesive layer may be roughened. Further, since the ultraviolet curable pressure-sensitive adhesive composition contains a large amount of solvent, a step of removing the solvent is required when producing the pressure-sensitive adhesive sheet.

The combination of the polyfunctional urethane acrylate and the monofunctional urethane acrylate of Patent Document 2 is insufficient in the adhesive force to the base material and the step followability. Further, although Patent Document 2 does not carry out a durability test (heat resistance, moisture resistance heat resistance, etc.), even if the durability test is performed, peeling or a decrease in step followability may occur after the test.

In the present invention, an active energy ray-curable pressure-sensitive adhesive composition, a cured product, and a pressure-sensitive adhesive sheet, which can be used without a solvent, have both high step followability and processability even with a single layer, and have excellent adhesive strength. The challenge is to provide.

The present inventors have diligently studied to solve the above-mentioned problems, and found that the above-mentioned problems can be solved by using a predetermined active energy ray-curable pressure-sensitive adhesive composition, a cured product thereof, and an adhesive sheet having the cured product thereof. The headline has completed the present invention.

That is, the present invention relates to the following items 1 to 8.
(Item 1)
Polyurethane, which is a reaction product of (A) (a1) polyol, (a2) aliphatic polyisocyanate, (a3) hydroxyl group-containing mono (meth) acrylate, and (a4) hydroxyl group-containing photopolymerization initiator,
(B) (b1) An alkyl mono (meth) acrylate having a linear alkyl group having no alicyclic structure and having 4 or more and 18 or less carbon atoms, and a branched alkyl group having no alicyclic structure having 4 to 18 carbon atoms. One or more alkyl mono (meth) acrylates selected from the following alkyl mono (meth) acrylates and (b2) alkyl mono (meth) acrylates having an alicyclic structure and having 6 or more and 15 or less carbon atoms. When,
(C) Containing mono (meth) acrylate containing a primary hydroxyl group,
The component (A3) is introduced in an amount of 10 mol% or more and 90 mol% or less with respect to the isocyanate group at the end of the urethane prepolymer composed of the component (a1) and the component (a2), and (a4). Ingredients are introduced in an amount of 10 mol% or more and 90 mol% or less.
Active energy ray-curable pressure-sensitive adhesive composition.
(Item 2)
When the total of the component (A), the component (B), and the component (C) is 100% by mass, the component (A) is 20% by mass or more and 70% by mass or less, and the component (B) is 25% by mass. The active energy ray-curable pressure-sensitive adhesive composition according to item 1, wherein the content is 75% by mass or more and the component (C) is 5% by mass or more and 55% by mass or less.
(Item 3)
(A1) The active energy ray-curable pressure-sensitive adhesive composition according to item 1 or 2, wherein the number average molecular weight of the components is 700 or more and 10,000 or less.
(Item 4)
The active energy ray-curable pressure-sensitive adhesive composition according to any one of items 1 to 3, wherein the component (a3) is a hydroxyl group-containing mono (meth) acrylate having 5 or more and 10 or less carbon atoms.
(Item 5)
The active energy ray-curable pressure-sensitive adhesive composition according to any one of Items 1 to 4, wherein the weight average molecular weight of the component (A) is 10,000 or more and 90,000 or less.
(Item 6)
A cured product of the active energy ray-curable pressure-sensitive adhesive composition according to any one of items 1 to 5.
(Item 7)
The cured product according to item 6, wherein the storage elastic modulus G'at 25 ° C. and 1 Hz is 8 × 10 ⁴ Pa or more, and the loss coefficient Tan δ at 50 ° C. and 1 Hz is 0.4 or more.
(Item 8)
An adhesive sheet having the cured product according to item 6 or 7 on at least one surface of the substrate surface.

Since the active energy ray-curable pressure-sensitive adhesive composition of the present invention can be used without a solvent, the solvent removal step can be omitted when producing the pressure-sensitive adhesive sheet. Further, even if the adhesive layer (hereinafter, also referred to as "cured product") of the active energy ray-curable pressure-sensitive adhesive composition of the present invention is a single layer, it has high step followability (that is, flexibility during heating) and processing. It has both properties (that is, toughness at room temperature) and exhibits excellent adhesive strength. In addition, the adhesive layer is colorless and transparent, and has excellent durability in a high temperature and high humidity environment.

The present invention
(A) (a1) polyol (hereinafter, also referred to as "(a1) component"), (a2) aliphatic polyisocyanate (hereinafter, also referred to as "(a2) component"), (a3) hydroxyl group-containing mono (meth). ) Acrylate (hereinafter, also referred to as "(a3) component") and (a4) hydroxyl group-containing photopolymerization initiator (hereinafter, also referred to as "(a4) component"), polyurethane (hereinafter, "(A) component"). ) Ingredients.)
(B) (b1) An alkyl mono (meth) acrylate having a linear alkyl group having no alicyclic structure and having 4 or more and 18 or less carbon atoms, and a branched alkyl group having no alicyclic structure having 4 to 18 carbon atoms. The following alkyl mono (meth) acrylates (hereinafter, also referred to as “(b1) component”) and (b2) alkyl mono (meth) acrylates containing an alicyclic structure and having 6 or more and 15 or less carbon atoms ( Hereinafter, one or more alkyl mono (meth) acrylates (hereinafter, also referred to as “(B) component”) selected from “(b2) component”) and
(C) Contains a primary hydroxyl group-containing mono (meth) acrylate (hereinafter, also referred to as “component (C)”).
The component (A3) is introduced in an amount of 10 mol% or more and 90 mol% or less with respect to the isocyanate group at the end of the urethane prepolymer composed of the component (a1) and the component (a2), and (a4). Ingredients are introduced in an amount of 10 mol% or more and 90 mol% or less.
The present invention relates to an active energy ray-curable pressure-sensitive adhesive composition (hereinafter, also referred to as “pressure-sensitive adhesive composition”). Each component will be described in detail below. In addition, in this specification, (meth) acrylate means acrylate and / or methacrylate.

<Ingredient (A)>
The component (A) is a polyurethane which is a reaction product of the component (a1), the component (a2), the component (a3) and the component (a4).

<(A1) component>
The component (a1) is a polyol. By using a polyol as the component (a1), the adhesive layer of the present invention is excellent in transparency and flexibility. In the present specification, the polyol refers to a substance having two or more hydroxyl groups. The component (a1) is not particularly limited, and various known components may be used. The component (a1) may be used alone or in combination of two or more. The component (a1) may be a crystalline polyol or a non-crystalline polyol.

As used herein, the crystalline polyol refers to a substance in which the polyol has a crystal structure, preferably at 20 ° C. or higher and 60 ° C. or lower, more preferably 20 ° C. or higher and 40 ° C. or lower, and most preferably 25 ° C.

Examples of the component (a1) include polyether polyols, polyester polyols, polymer polyols, poly (meth) acrylic polyols, polycarbonate polyols, castor oil-based polyols, and polyolefin polyols. In addition, in this specification, (meth) acrylic refers to acrylic and / or methacrylic.

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polytetramethylene glycol and the like.

The polyether polyol may be a commercially available product. The products include polyether diols (product name "Adeca polyether P series", manufactured by ADEKA Co., Ltd.), polyether triol (product name "Adeca polyether G series", manufactured by ADEKA Co., Ltd.), and polyether tetraol. (Product name "Adecapolyether EDP series", manufactured by ADEKA Co., Ltd.), Polyether polyol (Product name "Adecapolyether P1000" "Adecapolyether P2000", manufactured by ADEKA Co., Ltd.), Polyethylene glycol (Product name "Product name" Polyethylene glycol # 1,540 ”, manufactured by Nakarai Tesk Co., Ltd., dipropylene glycol (product name“ dipropylene glycol ”, manufactured by Genuine Chemical Co., Ltd.), polypropylene glycol (product name“ Polyethylene glycol 400 ”, genuine chemical ( Co., Ltd.), polytetramethylene ether glycol (product names "PTMG650", "PTMG1000", "PTMG2000", "PTMG3000", manufactured by Mitsubishi Chemical Co., Ltd.) and the like are exemplified.

The polyester polyol may be a commercially available product. The products include high refractive index grade polyester polyol (product name "Polylite RX-4800", manufactured by DIC Co., Ltd.) and high crystalline grade polyester polyol (product name "Polylite OD-X-2523" "Polylite OD-". X-2547 ", manufactured by DIC Co., Ltd., transparent grade polyester polyol (product name" Polylite OD-X-2420 "," Polylite OD-X-2692 ", manufactured by DIC Co., Ltd.), high adhesive grade polyester Polyester (product name "Polylite OD-X-2108", manufactured by DIC Co., Ltd.), polyester polyol (product name "ETERNACOLL3000 series", manufactured by Ube Kosan Co., Ltd.), polycaprolactone polyol (product name "Polylite OD-X-" 2155 ”, manufactured by DIC Co., Ltd., polycaprolactone diol (product name“ Plaxel 200 ”, manufactured by Daicel Co., Ltd.), polycaprolactone triol (product name“ Praxel 300 ”, manufactured by Daicel Co., Ltd.), polycaprolactone tetraol (Product name "Caprolactone 400", manufactured by Daicel Co., Ltd.) and the like are exemplified.

The polymer polyol may be a commercially available product. Examples of such products include polymer polyols (product names "Ultiflow series" and "Sharp Flow series", manufactured by Sanyo Chemical Industries, Ltd.), polymer polyols (product names "Exenol series", manufactured by AGC Inc.), and the like. To.

The poly (meth) acrylic polyol may be a commercially available product. The products include acrylic polyol (product name "acrylic polyol # 6000", manufactured by Taisei Fine Chemicals Co., Ltd.), acrylic polyol (product name "ETERAC7315-XS-60", manufactured by Changxing Materials Industry Co., Ltd.), acrylic polyol ( Examples thereof include the product name "acrylic polyol PC # 5984" and manufactured by Toei Kasei Co., Ltd.

The polycarbonate polyol may be a commercially available product. The products include polycarbonate diol (product name "Beneviol", manufactured by Mitsubishi Chemical Corporation), polycarbonate diol (product name "Nipporan series", manufactured by Tosoh Co., Ltd.), polycarbonate diol (product name "Duranol series"), Asahi Kasei Co., Ltd.) and the like are exemplified.

The castor oil-based polyol may be a commercially available product. The products include castor oil-based polyol (product name "URIC H series", manufactured by Ito Oil Co., Ltd.), castor oil-based polyol (product name "castor oil-based polyol HS CM-025P", "castor oil-based polyol HS CM-". 075P ”, manufactured by Toyokuni Oil Co., Ltd.) and the like are exemplified.

Examples of the polyolefin polyol include hydroxyl group-containing polybutadiene, hydrogenated hydroxyl group-containing polybutadiene, hydroxyl group-containing polyisoprene, hydrogenated hydroxyl group-containing polyisoprene, hydroxyl group-containing chlorinated polypropylene, and hydroxyl group-containing chlorinated polyethylene.

The polyolefin polyol may be a commercially available product. As the product concerned, polybutadiene diol (product name "Poly bd R-45HT" "Poly bd R-15HT", manufactured by Idemitsu Kosan Co., Ltd.) (product name "NISSO-PB B-1000" "NISSO-PB B-2000" "NISSO-PB G-1000" "NISSO-PB G-2000", manufactured by Nippon Soda Co., Ltd., hydrogenated polybutadiene diol (product name "NISSO-PB GI-1000" "NISSO-PB GI-2000", Japan (Manufactured by Nippon Soda Co., Ltd.) and the like are exemplified.

The component (a1) is preferably a polyol having crystallinity at 20 ° C. or higher and 60 ° C. or lower, and more preferably a crystalline polyether polyol, because the adhesive layer is excellent in toughness and adhesive strength at room temperature. The component (a1) is preferably one or more selected from the group consisting of a polyether polyol, a polycaprolactone polyol, and a polyolefin polyol from the viewpoint of being relatively excellent in moisture and heat resistance, and more preferably a polyether polyol and a polyolefin polyol. One or more selected from the group consisting of.

The number average molecular weight of the component (a1) is preferably 700 or more and 10,000 or less because the adhesive layer is excellent in adhesive strength and step followability. When the number average molecular weight of the component (a1) is less than the above lower limit, the adhesive layer tends to be hard, and when it exceeds the above upper limit, the adhesive layer tends to be soft. Therefore, the adhesive layer tends to be softer than the above preferable range. The force and step followability tend to be weak. In the present specification, the number average molecular weight can be determined by the method described in JIS K7252-1: 2016.

The number of hydroxyl groups of the component (a1) is preferably 1.5 or more and 3 or less, and more preferably 1.8 or more and 2.5 or less, because the adhesive layer is excellent in step followability and processability. In the present specification, the number of hydroxyl groups can be determined by the method described in JIS K1557-1: 2007. Specifically, in the present invention, the number of hydroxyl groups can be determined by an acetylation method.

<(A2) component>
The component (a2) is an aliphatic polyisocyanate. The component (a2) is not particularly limited, and various known components may be used. The component (a2) may be used alone or in combination of two or more.

Examples of the component (a2) include aliphatic diisocyanates, aliphatic triisocyanates, and aliphatic tetraisocyanates.

Examples of the component (a2) include linear aliphatic polyisocyanates, branched aliphatic polyisocyanates, and alicyclic aliphatic polyisocyanates.

Examples of the linear aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, and decamethylene diisocyanate.

Examples of the branched aliphatic diisocyanate include methyl 2,6-diisocyanatohexanoate and trimethylhexamethylene diisocyanate.

As the alicyclic aliphatic diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, cyclohexane-1,4-diylbis (methylene) diisocyanate, 1-methylcyclohexane Examples thereof include −2,4-diyl diisocyanate, 1,4-cyclohexane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated tolylene diisocyanate, and norbornene diisocyanate.

Examples of the linear aliphatic triisocyanate include lysine triisocyanate.

The component (a2) is preferably an aliphatic diisocyanate, more preferably a linear aliphatic diisocyanate and / or an alicyclic type, because the adhesive layer has excellent durability after a moist heat resistance test and excellent step followability. It is an aliphatic diisocyanate.

The component (a2) may be a commercially available product. The products include 1,5-pentamethylene diisocyanate (product name "Stavio PDI", manufactured by Mitsui Chemicals, Inc.), hexamethylene diisocyanate (product name "HDI", manufactured by Toso Co., Ltd.), 2,6-diisocia. Methyl natohexanoate (product name "LDI", manufactured by Chuo Kasei Co., Ltd.), trimethylhexamethylene diisocyanate (product code "T1176", manufactured by Tokyo Kasei Kogyo Co., Ltd.), dicyclohexylmethane 4,4'-diisocyanate (product) Name "H12MDI", manufactured by Chuo Kasei Products Co., Ltd. (Product name "VESTANAT H12MDI", manufactured by EVONIK INDUSTRIES AG), isophorone diisocyanate (product name "IPDI", manufactured by Chuo Kasei Products Co., Ltd.), Bis (Isocyanato) Examples thereof include methyl) cyclohexane (product name "Takenate 600", manufactured by Mitsui Chemicals, Inc.), lysine triisocyanate (product name "LTI", manufactured by Chuo Kasei Seisakusho Co., Ltd.) and the like.

The ratio (NCO _(a2) / OH _(a1) ) of the number of mols of the hydroxyl groups of the component (a1) (OH _(a1) ) to the number of mols of the isocyanate groups of the component _(a2) (NCO _{(a2 )} ) is usually 1. It is about 01 to 2.

<(A3) component>
The component (a3) is a hydroxyl group-containing mono (meth) acrylate. By using the component (a3), the pressure-sensitive adhesive composition has excellent curability and the pressure-sensitive adhesive layer has excellent processability. When the pressure-sensitive adhesive composition containing the component (a3) is produced, curing failure occurs and the pressure-sensitive adhesive layer becomes too soft at room temperature. When cutting a base material or the like containing such an adhesive layer, the adhesive layer tends to adhere to the surface of the blade of the cutting device, so that the pressure-sensitive adhesive composition containing the component (a3) is not preferable. The component (a3) is not particularly limited, and various known components may be used. The component (a3) may be used alone or in combination of two or more.

As hydroxyl group-containing mono (meth) acrylates, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, glycerol mono (meth) ) Acrylate, 2-hydroxy-3-phenoxypropyl acrylate and the like are exemplified.

The component (a3) is preferably a hydroxyl group-containing mono (meth) acrylate having 5 to 10 carbon atoms, and more preferably hydroxyethyl, because the pressure-sensitive adhesive composition is excellent in curability and the pressure-sensitive adhesive layer is excellent in processability. It is a (meth) acrylate.

The component (a3) may be a commercially available product. The products include 2-hydroxyethyl acrylate (product name "HEA", manufactured by Osaka Organic Chemical Industry Co., Ltd.), 2-hydroxyethyl methacrylate (product name "2-HEMA", manufactured by Mitsubishi Gas Chemical Co., Ltd.), 2 -Hydroxypropyl methacrylate (product name "light ester HOP (N)", manufactured by Kyoeisha Chemical Co., Ltd.) (product name "2-hydroxypropyl methacrylate", manufactured by Nippon Catalyst Co., Ltd.), 4-hydroxybutyl acrylate (product name) "4-HBA", manufactured by Osaka Organic Chemical Industry Co., Ltd., 2-hydroxybutyl methacrylate (product name "light ester HOB (N)", manufactured by Kyoeisha Chemical Co., Ltd.), 2-acryloyloxyethyl-2- Hydroxyethylphthalic acid (product name "HOA-MPE (N)", manufactured by Kyoeisha Chemical Co., Ltd.), 2-hydroxy-3-phenoxypropyl acrylate (product name "epoxy ester M-600A", manufactured by Kyoeisha Chemical Co., Ltd.) ) Etc. are exemplified.

The mol% of the component (a3) introduced into the isocyanate group at the end of the urethane prepolymer composed of the component (a1) and the component (a2) is such that the pressure-sensitive adhesive composition has excellent curability and the pressure-sensitive adhesive layer has processability. When the total of the component (a3) and the component (a4) is 100 mol%, it is 10 mol% or more and 90 mol% or less, preferably 20 mol% or more and 80 mol% or less.

<(A4) component>
The component (a4) is a hydroxyl group-containing photopolymerization initiator. By using the component (a4), the adhesive layer has excellent step followability. The component (a4) is not particularly limited, and various known components may be used. The component (a4) may be used alone or in combination of two or more.

As the component (a4), a primary monovalent hydroxyl group-containing photopolymerization initiator, a secondary monovalent hydroxyl group-containing photopolymerization initiator, a tertiary monovalent hydroxyl group-containing photopolymerization initiator, and a divalent hydroxyl group-containing light. Examples thereof include a polymerization initiator.

In the present specification, the monovalent hydroxyl group means that the number of hydroxyl groups is one. In the present specification, the divalent hydroxyl group means that the number of hydroxyl groups is two. In the present specification, the primary hydroxyl group refers to a substance in which one carbon atom is bonded to the carbon atom to which the hydroxyl group is bonded. In the present specification, the secondary hydroxyl group refers to a substance in which two carbon atoms are bonded to a carbon atom to which the hydroxyl group is bonded. In the present specification, the tertiary hydroxyl group refers to a substance in which three carbon atoms are bonded to the carbon atom to which the hydroxyl group is bonded.

Examples of the secondary monovalent hydroxyl group-containing photopolymerization initiator include 2-hydroxy-2-phenylacetophenone.

Examples of the tertiary monovalent hydroxyl group-containing photopolymerization initiator include 1-hydroxycyclohexylphenyl ketone and 2-hydroxy-2-methyl-1-phenyl-propane-1-one.

As a divalent hydroxyl group-containing photopolymerization initiator, 2-hydroxy-4'-(2-hydroxyethoxy) -2-methylpropiophenone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy- 2-Methyl-1-propane-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{ Examples thereof include 4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one.

The component (a4) is preferably a tertiary monovalent hydroxyl group-containing photopolymerization initiator because the adhesive layer has excellent step-following property, and more preferably 1-hydroxycyclohexylphenylketone and / or 2-hydroxy-. It is 2-methyl-1-phenyl-propane-1-one.

The component (a4) may be a commercially available product. The products include 2-hydroxy-2-phenylacetophenone (product code "B0079", manufactured by Tokyo Kasei Kogyo Co., Ltd.), 1-hydroxy-cyclohexyl-phenyl-ketone (product name "OMNIRAD184", manufactured by IGM Resins) ( Product name "Luna200", manufactured by DKSH Japan Co., Ltd., 2-Hydroxy-2-methyl-1-phenyl-propane-1-one (product name "OMNIRAD1173", manufactured by IGM Resins) (product name "Luna100") , DKSH Japan Co., Ltd., 2-Hydroxy-4'-(2-Hydroxyethoxy) -2-methylpropiophenone (product code "H1361", manufactured by Tokyo Kasei Kogyo Co., Ltd.), 1- [4 -(2-Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (product name "OMNIRAD2959", manufactured by IGM Resins), 2-hydroxy-1- {4- [4] -(2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one (product name "OMNIRAD127", manufactured by IGM Resins) and the like are exemplified.

The mol% of the component (a4) introduced into the isocyanate group at the end of the urethane prepolymer composed of the component (a1) and the component (a2) is the component (a3) because the adhesive layer has excellent step followability. When the total of the components (a4) is 100 mol%, it is 10 mol% or more and 90 mol% or less, and more preferably 20 mol% or more and 80 mol% or less.

Mol ratio of component (a3) and component (a4) introduced into the isocyanate group at the end of the urethane prepolymer composed of component (a1) and component (a2) ([(a3) component mol] / [(a4) ) Component mol]) is preferably 1/9 to 9/1, more preferably 1/5 to 3/1, because the adhesive layer has excellent step followability and the adhesive layer has excellent processability. ..

The "mol ratio of the component (a3) and the component (a4) introduced into the isocyanate group at the end of the urethane prepolymer composed of the component (a1) and the component (a2)" is the terminal of the urethane prepolymer. It is the ratio of the component (a3) and the component (a4) reacting with the isocyanate group in. In order to obtain the component (A) in which the component (a3) and the component (a4) have a desired mol ratio, the amount of the component (a3) that reacts with all of the isocyanate groups present in the urethane prepolymer is required. The components (a4) may be mixed at a desired mol ratio and reacted.

<Additives that can be added to other (A) ingredients>
Various additives may be included in the component (A), if necessary. The additive may be of various known ones. The additive may be used alone or in combination of two or more.

Examples of the additive include a catalyst, a crystal nucleating agent, a crystallization accelerator, a chain transfer agent, and the like.

The method for producing the component (A) is not particularly limited, but various known methods for producing polyurethane can be adopted. As the component (A), the component (a1) and the component (a2) are reacted to once produce a urethane prepolymer having one or more isocyanate groups at the end (hereinafter, the component (A')), and then (A'). ), The component (a3) and the component (a4) are reacted. The reaction temperature and reaction time are not particularly limited, but are usually 70 ° C. or higher and 85 ° C. or lower, 1 hour or longer and 5 hours or lower. When appropriately producing the polyurethane resin, the component (b1) and the component (b2) of the present invention can be used as a diluent, and the component (b1) is preferable. A polymerization inhibitor may be used in the reaction system so that the component (a3) does not polymerize.

The weight average molecular weight of the component (A) is preferably 10,000 or more and 90,000 or less, and more preferably 20,000 or more and 70,000 or less because the adhesive layer is excellent in adhesive strength and step followability. .. If the weight average molecular weight of the component (A) is less than the above lower limit, the adhesive strength of the pressure-sensitive adhesive layer tends to be weakened, and if it exceeds the above upper limit, the viscosity of the pressure-sensitive adhesive composition tends to be high, which tends to make production difficult. .. In the present specification, the weight average molecular weight is a polystyrene-equivalent value obtained by a gel permeation chromatography method.

The content of the component (A) is the total of the components (A), (B), and (C) because the pressure-sensitive adhesive composition has excellent curability and the pressure-sensitive adhesive layer has excellent adhesive strength and step-following property. In terms of solid content, it is preferably 20% by mass or more and 70% by mass or less, more preferably 20% by mass or more and 60% by mass or less, and even more preferably 25% by mass or more and 50% by mass. % Or less.

<Ingredient (B)>
The component (B) is one or more selected from the following components (b1) and (b2).

<(B1) component>
The component (b1) is an alkyl mono (meth) acrylate having 4 or more and 18 or less carbon atoms of a linear alkyl group having no alicyclic structure and a branched alkyl group having 4 or more and 18 carbon atoms having no alicyclic structure. One or more alkyl mono (meth) acrylates selected from the following alkyl mono (meth) acrylates. By using the component (b1), the adhesive layer has excellent step followability. The component (b1) may be of various known ones. The component (b1) may be used alone or in combination of two or more. When the number of carbon atoms of the alkyl group in the alkyl mono (meth) acrylate of the component (b1) is 19 or more, the compatibility is poor and it is difficult to achieve the effect of the present invention. Further, when the number of carbon atoms of the alkyl group in the alkyl mono (meth) acrylate of the component (b1) is 3 or less, the boiling point is low, so that the storage stability of the product is lacking.

As alkyl mono (meth) acrylates having 4 or more and 18 or less carbon atoms in a linear alkyl group containing no alicyclic structure, n-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, and heptyl (meth) Examples thereof include meta) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, hexadecyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate.

Isoamyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and isodecyl (meth) acrylate as alkyl mono (meth) acrylates having 4 or more and 18 or less carbon atoms in a branched alkyl group containing no alicyclic structure. , Isostearyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like are exemplified.

The component (b1) may be a commercially available product. The products include butyl acrylate (product name "butyl acrylate", manufactured by Toa Synthetic Co., Ltd.), nonyl acrylate (product name "Viscort # 197", manufactured by Osaka Organic Chemical Industry Co., Ltd.), lauryl acrylate (product name " Light Acrylate LA ", Kyoeisha Chemical Co., Ltd.), Stearyl Acrylate (Product Name" Light Acrylate SA ", Kyoeisha Chemical Co., Ltd.), Isostearyl Acrylate (Product Name" ISTA ", Osaka Organic Chemistry (Osaka Organic Chemistry) (Manufactured by Co., Ltd.), Isoamyl acrylate (Product name "Light acrylate IAA", manufactured by Kyoeisha Chemical Co., Ltd.), Isononyl acrylate (Product name "Isononyl acrylate", manufactured by Osaka Organic Chemical Industry Co., Ltd.), Isodecyl acrylate ( Examples thereof include product name "IDAA", manufactured by Osaka Organic Chemical Industry Co., Ltd., 2-ethylhexyl acrylate (product name "-2-ethylhexyl acrylate", manufactured by Mitsubishi Chemical Co., Ltd.) and the like.

The content of the component (b1) is in terms of solid content when the total of the components (A), (B), and (C) is 100% by mass because the adhesive layer has excellent step-following property. It is preferably 15% by mass or more and 65% by mass or less, more preferably 15% by mass or more and 60% by mass or less, and even more preferably 20% by mass or more and 50% by mass or less.

<(B2) component>
The component (b2) is an alkyl mono (meth) acrylate having an alicyclic structure and having an alkyl group having 6 or more and 15 or less carbon atoms. By using the component (b2), the adhesive layer is excellent in processability. The component (b2) may be of various known ones. The component (b2) may be used alone or in combination of two or more.

As the component (b2), cyclohexyl (meth) acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate , Dicyclopentenyl (meth) acrylicate and the like are exemplified.

The component (b2) is preferably cyclohexyl (meth) acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, orisobornyl (b2) because the adhesive layer is excellent in processability. One or more selected from the group consisting of a meta) acrylate and a dicyclopentanyl (meth) acrylate, more preferably an isobornyl (meth) acrylate and / or a dicyclopentanyl (meth) acrylate.

The component (b2) may be a commercially available product. The products include cyclohexyl methacrylate (product name "Light Ester CH", manufactured by Kyoeisha Chemical Co., Ltd.), cyclohexyl acrylate (product name "Viscort # 155", manufactured by Osaka Organic Chemical Industry Co., Ltd.), 4-t-butylcyclohexyl. Methacrylate (product name "4-t-butylcyclohexyl methacrylate", manufactured by MCC Unitech Co., Ltd.), 4-t-butylcyclohexyl acrylate (product name "Blemmer TBCHA" manufactured by Nichiyu Co., Ltd.), isobornyl acrylate ( Product name "IBXA", manufactured by Osaka Organic Chemical Industry Co., Ltd., dicyclopentanyl acrylate (product name "FA-513AS", manufactured by Hitachi Chemical Co., Ltd.), dicyclopentenyl acrylicate (product name "FA") -511AS ”, manufactured by Hitachi Kasei Co., Ltd., etc. are exemplified.

The number of carbon atoms of the alkyl group containing the alicyclic structure of the component (b2) is 6 or more and 15 or less, preferably 6 or more and 10 or less.

The content of the component (b2) is preferable in terms of solid content when the total of the components (A), (B) and (C) is 100% by mass because the adhesive layer is excellent in processability. Is 10% by mass or more and 60% by mass or less, more preferably 15% by mass or more and 60% by mass or less, and even more preferably 15% by mass or more and 50% by mass or less.

It is particularly preferable that the component (B) contains both the component (b1) and the component (b2) because the adhesive layer is excellent in both step-following property and processability.

The content of the component (B) is preferably 25% by mass or more and 75% by mass or less in terms of solid content when the total of the components (A), (B) and (C) is 100% by mass. Yes, more preferably 30% by mass or more and 70% by mass or less, and even more preferably 30% by mass or more and 65% by mass or less.

<Component (C)>
The component (C) is a primary hydroxyl group-containing mono (meth) acrylate. By using the component (C), the pressure-sensitive adhesive composition has excellent curability, and the pressure-sensitive adhesive layer has excellent durability after a moist heat resistance test. The component (C) is not particularly limited, and various known components may be used. The component (C) may be used alone or in combination of two or more. When a mono (meth) acrylate having no hydroxyl group is used as a substitute for the component (C), the durability after the moisture resistance test and the haze value after the moisture resistance test are inferior. Further, when a secondary hydroxyl group-containing mono (meth) acrylate is used as a substitute for the component (C), the haze value after the moist heat resistance test is inferior.

Examples of the component (C) include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate and the like.

The component (C) is preferably 2-hydroxyethyl (meth) acrylate and / or 4-hydroxybutyl (meth) because the pressure-sensitive adhesive composition has excellent curability and the pressure-sensitive adhesive layer has excellent durability after a moist heat resistance test. ) It is an acrylate.

The component (C) may be a commercially available product. The products include 2-hydroxyethyl acrylate (product name "HEA", manufactured by Osaka Organic Chemical Industry Co., Ltd.), 2-hydroxyethyl methacrylate (product name "2-HEMA", manufactured by Mitsubishi Gas Chemical Company, Inc.), 4 -Hydroxybutyl acrylate (product name "4-HBA", manufactured by Osaka Organic Chemical Industry Co., Ltd.), 1,4-cyclohexanedimethanol monoacrylate (product name "CHDMMA", manufactured by Mitsubishi Chemical Co., Ltd.), etc. are exemplified. To.

The content of the component (C) is the total of the components (A), (B), and (C) because the pressure-sensitive adhesive composition has excellent curability and the pressure-sensitive adhesive layer has excellent durability after the moisture resistance test. In terms of solid content, it is preferably 5% by mass or more and 55% by mass or less, more preferably 5% by mass or more and 50% by mass or less, and even more preferably 10% by mass or more and 40% by mass. % Or less.

<Ingredient (D)>
Since the pressure-sensitive adhesive layer is excellent in curability, the pressure-sensitive adhesive composition of the present invention preferably contains a radical-based photopolymerization initiator (hereinafter, also referred to as “component (D)”). The component (D) is not particularly limited, and various known components may be used. The component (D) may be used alone or in combination of two or more.

Examples of the component (D) include an alkylphenone type photopolymerization initiator, an acylphosphine oxide type photopolymerization initiator, a hydrogen abstraction type photopolymerization initiator, and an oxime ester type photopolymerization initiator.

As an alkylphenone-type photopolymerization initiator, benzyl dimethyl ketal such as 2,2-dimethoxy-1,2-diphenylethane-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy- Α-Hydroxyalkylphenone such as 2-methyl-1-propane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 2-methyl Examples thereof include α-aminoalkylphenone such as -1- (4-methylthiophenyl) -2-morpholinopropane-1-one.

Examples of the acylphosphine oxide type photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and the like.

Examples of the hydrogen abstraction type photopolymerization initiator include phenylglycoxylic acid methyl ester and the like.

As an oxime ester type photopolymerization initiator, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], etanone, 1- [9-ethyl-6- (2-) Methylbenzoyl) -9H-carbazole-3-yl]-, 1- (O-acetyloxime) and the like are exemplified.

The component (D) is preferably an α-hydroxyalkylphenone type photopolymerization initiator and / or an acylphosphine oxide type photopolymerization initiator because the pressure-sensitive adhesive composition is excellent in curability.

The component (D) may be a commercially available product. The products include 2,2-dimethoxy-1,2-diphenylethane-1-one (product name "OMNIRAD 651", manufactured by IGM Resins), 2-hydroxy-2-methyl-1-phenyl-propane-1-. On (product code "H0991", manufactured by Tokyo Kasei Kogyo Co., Ltd.) (product name "OMNIRAD1173", manufactured by IGM Resins) (product name "Luna100", manufactured by DKSH Japan Co., Ltd.), 1-hydroxy-cyclohexyl- Phenyl-ketone (product name "OMNIRAD184", manufactured by IGM Resins) (product name "Luna200", manufactured by DKSH Japan Co., Ltd.), 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy- 2-Methyl-1-propane-1-one (product name "OMNIRAD 2959", manufactured by IGM Resins), 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one (product name) "OMNIRAD 907", manufactured by IGM Resins), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (product name "OMNIRAD TPO", manufactured by IGM Resins), bis (2,4,6-trimethylbenzoyl) -Phenylphosphine oxide (product name "OMNIRAD 819", manufactured by IGM Resins), phenylglycolic acid methyl ester (product name "OMNIRAD MBF", manufactured by IGM Resins), 1,2-octanedione, 1-[ 4- (Phenylthio)-, 2- (O-benzoyloxime)] (Product name "OMNIRAD OXE 01", manufactured by IGM Resins), Etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H -Carbazole-3-yl]-, 1- (O-acetyloxime) (product name "OMNIRAD OXE 02", manufactured by IGM Resins) and the like are exemplified.

As for the content of the component (D), the total of the components (A), (B), and (C) was set to 100% by mass because the adhesive layer is excellent in curability and durability after the moisture resistance test. In some cases, it is preferably 0.1% by mass or more and 3% by mass or less in terms of solid content, more preferably 0.2% by mass or more and 2% by mass or less, and even more preferably 0.2% by mass or more. It is 5% by mass or less.

<Other additives that can be blended>
The pressure-sensitive adhesive composition of the present invention may contain various additives, if necessary.

The additive is not particularly limited, and various known additives may be used. The additive may be used alone or in combination of two or more.

As additives, surface conditioners, surfactants, UV absorbers, antioxidants, light stabilizers, tackifiers, inorganic fillers, silane coupling agents, colloidal silica, defoamers, wetting agents, rust preventives, Examples thereof include plasticizers, chain transfer agents, and photosensitizers.

The pressure-sensitive adhesive composition of the present invention may contain a solvent. The solvent is not particularly limited, and various known solvents may be used. The solvent may be used alone or in combination of two or more.

Examples of the solvent include a ketone solvent, an aromatic solvent, an alcohol solvent, a glycol ether solvent, an ester solvent, a petroleum solvent, a haloalkane solvent, an amide solvent and the like.

Examples of the ketone solvent include methyl ethyl ketone, acetylacetone, methyl isobutyl ketone, cyclohexanone and the like.

Examples of the aromatic solvent include toluene and xylene.

Examples of the alcohol solvent include methanol, ethanol, n-propanol, isopropanol, butanol and the like.

Examples of the glycol ether solvent include ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, and propylene glycol monomethyl ether acetate.

Examples of the ester solvent include ethyl acetate, butyl acetate, methyl cellosolve acetate and cellosolve acetate.

Examples of the petroleum-based solvent include Solbesso 100 (manufactured by ExxonMobil) and Solbesso 150 (manufactured by ExxonMobil).

Chloroform and the like are exemplified as the haloalkane solvent.

Examples of the amide solvent include dimethylformamide and the like.

The pressure-sensitive adhesive composition of the present invention can be used without containing a solvent. Therefore, the pressure-sensitive adhesive composition of the present invention preferably does not contain a solvent from the viewpoint of suppressing the cost and the influence on the environment.

The viscosity (mPa · s / 25 ° C.) of the pressure-sensitive adhesive composition of the present invention is preferably 100 or more and 10,000 or less, and more preferably 300 or more and 8,000 or more, because the pressure-sensitive adhesive composition is excellent in handleability. It is less than or equal to, and even more preferably 500 or more and 7,000 or less. In the present invention, the viscosity is a value (5 minutes) measured by an E-type viscometer (product name "TVE-10", manufactured by Toki Sangyo Co., Ltd.).

The pressure-sensitive adhesive composition of the present invention can be obtained by mixing the component (A), the component (B) and the component (C), and if necessary, the component (D) and other additives that can be blended. The order of mixing is not particularly limited, but they may be mixed sequentially or all at once.

<Cured product>
A product cured by irradiating the pressure-sensitive adhesive composition with active energy rays such as ultraviolet rays is also one of the present inventions.

When the pressure-sensitive adhesive composition contains a solvent, it is conceivable to carry out a drying treatment before irradiating with ultraviolet rays.

Examples of the ultraviolet light source include an ultraviolet irradiation device having a xenon lamp, a high-pressure mercury lamp, and a metal halide lamp. In said device, the irradiation intensity and the integrated quantity of ultraviolet light, as well as conditions such as the conveying speed is not particularly limited, usually, the irradiation intensity is 80 mW / cm ² or more 160 mW / cm ² or less, 50 m / min carrying speed is 3m / min or more hereinafter, the integrated light quantity is 100 mJ / cm ² or more 3,000 mJ / cm ² or less.

The pressure-sensitive adhesive composition may be applied to various plastic film substrates to form a layer of the pressure-sensitive adhesive composition, and then the layer may be irradiated with ultraviolet rays to obtain a cured product.

Examples of the coating method of the pressure-sensitive adhesive composition include bar coater coating, Mayer bar coating, air knife coating, gravure coating, reverse gravure coating, offset printing, flexographic printing, screen printing, and the like.

The amount of coating is usually in the range where the mass after drying is 1 g / m ² or more and 1,000 g / m ² or less, preferably 3 g / m ² or more and 500 g / m ² or less.

The thickness of the cured product of the present invention is not particularly limited, but the pressure-sensitive adhesive layer preferably exhibits step-following property, and bubbles are unlikely to occur. Therefore, the coating film after drying is preferably 10 μm or more and 1,000 μm or less. , More preferably 25 μm or more and 500 μm or less.

The cured product of the present invention has a storage elastic modulus G'(hereinafter, also referred to as "G'") at 25 ° C. and 1 Hz, preferably 8 × 10 ⁴ Pa or more, and more preferably 8 × 10 ⁴ Pa or more 1 × 10 ⁷ Pa or less. Further, the loss coefficient Tanδ (hereinafter, also referred to as “Tanδ”) at 50 ° C. and 1 Hz is preferably 0.4 or more, and more preferably 0.4 or more and 2 or less. Since the cured product has such characteristics, the cured product has both workability (G'at room temperature) and step followability (Tanδ at the time of heating), and has excellent adhesive strength and excellent durability after a moist heat resistance test. Is thought to play. In terms of such effects, G'is even more preferably 1 × 10 ⁵ Pa or more and 1 × 10 ⁷ Pa or less, and Tan δ is even more preferably 0.5 or more and 1.5 or less. In the present specification, the storage elastic modulus and the loss coefficient of the cured product can be determined by the method described in JIS K7244-1: 1998.

Specifically, the storage elastic modulus and the loss coefficient are measured by a commercially available measuring machine (product name "MCR302", manufactured by Anton Pearl Co., Ltd.) under the following conditions. Then, from the measurement results, the storage elastic modulus G'at 25 ° C. and the loss coefficient at 50 ° C. are obtained.

Deformation mode: Torsion measurement frequency: 1Hz
Strain: 0.01 to 1% AUTO setting Temperature rise rate: 3 ° C / min Measurement temperature: 25 to 50 ° C
Shape: Parallel plate 8.0 mmφ

In the present specification, the storage elastic modulus (G') is a value proportional to the maximum energy accumulated through the load cycle, and represents the rigidity of the adhesive layer. The rigidity is the difficulty of deformation due to an external force such as bending or twisting. The larger the value of the storage elastic modulus at 25 ° C. and 1 Hz, the higher the rigidity of the adhesive layer at 25 ° C., and the smaller the value, the lower the rigidity of the adhesive layer at 25 ° C. Since the preferable storage elastic modulus G'at 25 ° C. and 1 Hz of the cured product of the present invention is 8 × 10 ⁴ Pa or more, the cured product of the present invention is excellent in processability at room temperature.

In the present specification, the loss coefficient (Tanδ) refers to the ratio of the loss elastic modulus to the storage elastic modulus (G'). This shows how much energy the material absorbs (turns into heat) as it deforms. The smaller the value of the loss coefficient Tanδ at 50 ° C. and 1 Hz, the less energy is absorbed at 50 ° C., and the larger the value, the more energy is absorbed at 50 ° C. (that is, it is easily deformed). Since the preferable loss factor Tan δ of the cured product of the present invention at 50 ° C. and 1 Hz is 0.4 or more, the cured product of the present invention has excellent step followability at 50 ° C.

<Molded product>
As an application example of the pressure-sensitive adhesive composition, coating between base materials of various known articles is exemplified. These articles are not particularly limited and may be of various known ones.

The articles include the main body of home appliances such as refrigerators, televisions or air conditioners, their remote controls, housings and displays of information terminals such as mobile phones, smartphones, tablets and personal computers, and plastic molded products such as automobile parts or automobile interior materials. Is exemplified.

The active energy ray-curable pressure-sensitive adhesive composition of the present invention is suitable for optical applications. For example, it can be applied to a display panel having a multi-layer structure in a digital display device. Further, as described above, the adhesive strength is excellent and the step followability is also good. Therefore, for example, when applied to a double-sided adhesive sheet for a touch panel, a decorative plate or an icon sheet may be attached on the panel, or the sheet may be static. Bubbles are less likely to be generated when a transparent substrate on which a transparent electrode is formed in a capacitive touch panel and a transparent plate made of glass, plastic, or the like are bonded together. In addition, the adhesive layer is tough at room temperature, and the problem that the cut portion adheres to the punching blade and cannot be separated during the punching process and the problem that the adhesive layer adheres to the punching blade are less likely to occur, and it is possible to process into various shapes. It is possible. Since the adhesive layer of the present invention is excellent in transparency, it is suitable to be used for a display such as a television, a smartphone or a tablet.

<Applicable base material>
The pressure-sensitive adhesive composition of the present invention can be applied to various substrates such as metals, plastics, films and glass. The various base materials may be various known ones. The various base materials may be used alone or in combination of two or more.

Examples of various base materials include various known metals, plastics, films, glass, and other resins.

Examples of the metal include iron, aluminum, aluminum-plated steel sheet, chin-free steel sheet (TFS), stainless steel sheet, zinc phosphate-treated steel sheet, and zinc-zinc alloy plated steel sheet (bonded steel sheet).

Examples of plastics include ABS, polyimide (PI), polybutene (PB), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene (PE) such as polyethylene terephthalate (PET), and polymethacrylic acid. Acrylics such as methyl (PMMA), FRP and the like are exemplified.

As films, PET film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, Examples thereof include an ionomer resin film, an ethylene / (meth) acrylic acid copolymer film, an ethylene / (meth) acrylic acid ester copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, and a fluororesin film.

Examples of other base materials include epoxy resin, melamine resin, triacetyl cellulose resin, ABS resin, AS resin, norbornene resin and the like.

Since the adhesive layer of the present invention is excellent in transparency, it is particularly preferable to use it for optical applications. That is, the adhesive layer of the present invention is particularly suitable for laminating optical substrates. The pressure-sensitive adhesive layer of the present invention is suitable for use as an optical transparent pressure-sensitive adhesive (hereinafter, also referred to as "OCA").

The optical substrate of the present invention is not particularly limited, and various known materials may be used. The optical substrate may be used alone or in combination of two or more.

As an optical substrate, polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate (PEN), polyethylene films, polypropylene films, cellophane, diacetyl cellulose films, triacetyl cellulose films, acetyl cellulose butyrate films, Polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether ether ketone film, polyether sulfone film, polyether Examples thereof include plastic films such as imide film, polyimide film, fluororesin film, polyamide film, acrylic resin film, norbornene resin film and cycloolefin resin film, glass, tin-doped indium oxide film, ITO film and transparent conductive film.

Specifically, as a combination of the adhesive layer of the present invention and an optical base material,
(1) Glass, adhesive layer of the present invention, transparent conductive film (hereinafter, also referred to as "ITO")
(2) Support film, adhesive layer of the present invention, ITO
(3) Support film, adhesive layer of the present invention, liquid crystal display (4) Glass, adhesive layer of the present invention, liquid crystal display and the like.

Hereinafter, the present invention will be described in more detail with reference to Production Examples, Comparative Production Examples, Examples, Comparative Examples, Evaluation Examples, and Comparative Evaluation Examples, but the present invention is not limited to these Examples. In the following description, parts and% are based on mass.

In this example, the weight average molecular weight (Mw) was measured by gel permeation chromatography (GPC) under the following conditions.
(GPC measurement conditions)
Model: Product name "HLC-8220GPC" (manufactured by Tosoh Corporation)
Column: Product names "TSKgel G1000H""TSKgelG2000H" (manufactured by Tosoh Corporation)
Developing solvent: Tetrahydrofuran Flow rate: 0.6 mL / min Measurement temperature: 40 ° C
Detector: Differential Refractometer (RI: Reflective Index Detector)
Standard: Monodisperse polystyrene sample: A 20 μL solution obtained by preparing a tetrahydrofuran solution having a concentration of 0.2% in terms of solid content from a resin and filtering the solution with a microfilter.

In each production example, the NCO measurement method for urethane prepolymer is as follows: Measuring device body: Potential difference automatic titrator (product name "AT-400", manufactured by Kyoto Electronics Co., Ltd.)
Measurement procedure:
1: Weigh the sample into a weighing bottle of about 0.500 g or more and 1.000 g or less.
2: Inject 10 mL of a toluene solution of 0.15 mol / L dibutylamine.
3: Place the weighing bottle containing the sample in an ultrasonic cleaner to completely dissolve the sample.
4: Confirm that the sample is completely dissolved, and leave it for 15 minutes (direct sunlight, a place not exposed to heat).
After 5:15 minutes, add 100 mL of isopropyl alcohol to the weighing bottle. Place the stirrer piece in a weighing bottle.
Titration is performed using a 6: 0.1 mol / L hydrochloric acid solution (f = 1.00) to determine the NCO value.
After inputting the sample amount to be measured into the automatic titrator, the measurement is performed. It is acceptable if the measurement difference is within 0.30. If it is 0.30 or more, measure one again and confirm that it is within 0.30.

<Production Example 1: Preparation of (A) -1 component>
Polytetramethylene ether glycol (product name "PTMG2000", Mitsubishi Chemical Corporation) with a number average molecular weight of 2,000 as a component (a1) in a reaction vessel equipped with a stirrer, thermometer, dropping funnel, cooling tube and air inlet. (Manufactured by) (hereinafter, also referred to as "PTMG2000") 863 parts, (a2) Hexamethylene diisocyanate (product name "HDI", manufactured by Toso Co., Ltd.) (hereinafter, also referred to as "HDI") 97 parts, 2 -Ethylhexyl acrylate (product name "-2-ethylhexyl acrylate", manufactured by Mitsubishi Chemical Corporation) (hereinafter, also referred to as "2-EHA") 333 parts and 0.5 part of tin octylate are added at 70 ° C. 2 The reaction was carried out for a time to obtain a 2-EHA solution of an isocyanate group-terminated urethane prepolymer as an intermediate. 17 parts of 2-hydroxyethyl acrylate (product name "HEA", manufactured by Osaka Organic Chemical Industry Co., Ltd.) (hereinafter, also referred to as "HEA") as a component (a3), as a component (a4) in the obtained reaction product. 23 parts of 2-hydroxy-2-methyl-1-phenyl-propane-1-one (product name "Luna100", manufactured by DKSH Japan Co., Ltd.) (hereinafter, also referred to as "L100") are mixed and heated to 70 ° C. 2 The reaction was carried out by incubating for a long time, and the completion of the reaction was confirmed by NCO measurement to obtain a 2-EHA solution of the reaction product (hereinafter, "(A) -1 component").

<Production Examples 2 to 5 and Comparative Production Examples 1 to 4: Preparation of (A) -2 component to (A) -5 component and (A) -C1 to (A) -C4 component>
The procedure was carried out in the same manner as in Production Example 1 except that the components were changed as shown in Table 1. In Table 2, mol% of the component (a3) and mol% of the component (a4) introduced into the isocyanate group at the end of the urethane prepolymer composed of the components (a1) and (a2). Is shown.

<Production Example 6: Preparation of (A) -6 component>
Production Example 1 except that 333 parts of an isobornyl acrylate (hereinafter, also referred to as “IBXA”) solution was used instead of the 2-EHA solution, and the components (a1) to (a4) were changed to those shown in Table 1. It was carried out in the same manner as.

<Comparative Production Example 5: Preparation of (A) -C5 Component>
To the same reaction apparatus as in Production Example 1, 683 parts of PTMG2000 as a component (a1), 77 parts of HDI, 333 parts of 2-EHA and 0.5 part of tin octylate as a component (a2) are added and reacted at 70 ° C. for 2 hours. , A 2-EHA solution of an isocyanate group-terminated urethane prepolymer as an intermediate was obtained. 227 parts of PTMG2000 as a component (a1) and 13 parts of HEA as a component (a3) were mixed with the obtained reaction product, kept warm at 70 ° C. for 2 hours for reaction, and the reaction was confirmed by NCO measurement to confirm the completion of the reaction. A 2-EHA solution of the product (hereinafter, "(A) -C5 component") was obtained. The mol% of the component (a3) in the component (A) -C5 was 50 mol%, and the mol% of the component (a4) was 0 mol%.

The numbers in Table 1 indicate the mass parts of the component (a1), the component (a2), the component (a3), and the component (a4) in the component (A). The meanings of the terms in Table 1 are as follows.
PTMG2000: Polytetramethylene ether glycol (product name "PTMG2000", manufactured by Mitsubishi Chemical Corporation)
L220AL: Polycaprolactone polyol (product name "Plaxel L220AL", manufactured by Daicel Corporation)
HDI: Hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation)
IPDI: Isophorone diisocyanate (product name "VESTANAT IPDI", manufactured by Evonik Japan Co., Ltd.)
HEA: 2-Hydroxyethyl acrylate (product name "HEA", manufactured by Osaka Organic Chemical Industry Co., Ltd.)
L100: 2-Hydroxy-2-methyl-1-phenyl-propane-1-one (product name "Luna100", manufactured by DKSH Japan K.K.)
L200: 1-Hydroxycyclohexylphenyl ketone (product name "Luna200", manufactured by DKSH Japan K.K.)

<Example 1: Preparation of adhesive composition (1)>
As component (A), component (A) -1 of Production Example 1, component (b1) 2-EHA, component (b2) isobornyl acrylate (product name "IBXA", manufactured by Osaka Organic Chemical Industry Co., Ltd., Hereinafter, the pressure-sensitive adhesive composition (1) was obtained by mixing IBXA), HEA as the component (C), and L200 as the component (D) so as to have a mass% as shown in Table 3.

<Examples 2 to 12 and Comparative Examples 1 to 7: Adhesive Compositions (2) to (12) and Adhesive Compositions (C1) to (C7)>
The procedure was carried out in the same manner as in Example 1 except that the components were changed as shown in Tables 3 and 4.

<Performance evaluation (1): Viscosity (mPa · s)>
A commercially available measuring machine for measuring the viscosities of the pressure-sensitive adhesive compositions (1) to (12) and the pressure-sensitive adhesive compositions (C1) to (C7) (product name "TVE-10 type viscometer", manufactured by Toki Sangyo Co., Ltd.) Was measured at 25 ° C.

<Performance evaluation (2): Storage elastic modulus (G') and loss factor Tanδ>
Any of the pressure-sensitive adhesive compositions (1) to (12) and (C1) to (C7) can be applied to a 75 μm-thick heavy-peeling polyester film (product name “SP-PET-03-75BU”, manufactured by Panac Co., Ltd.). ), A light peeling polyester film (product name "SP-PET-01-38BU") with a thickness of 38 μm is applied to the pressure-sensitive adhesive composition coating layer so that the thickness of the pressure-sensitive adhesive layer after curing is 200 μm. (Made by Co., Ltd.) to bond the peeled surfaces. Next, the obtained coating film was applied to a high-pressure mercury lamp (other than the pressure-sensitive adhesive compositions (9) and (C4): 100 mW / cm ² , 900 mJ / cm ² , pressure-sensitive adhesive compositions (9) and (C4)) in the air. : By irradiating ultraviolet rays at 100 mW / cm ² , 3,000 mJ / cm ² ), a laminated film containing an adhesive layer (light peeling polyester film / adhesive layer / heavy peeling polyester film) was produced. Next, a 1 cm × 1 cm test piece was cut out from the laminated film. Next, the lightly peeled polyester film and the heavy peeled polyester film are peeled off from the test piece, and the sheets (adhesive sheets (1) to (12)) and (adhesive sheets (1) to (12)) consisting of only an adhesive layer (hereinafter, also referred to as "cured product") C1) to (C7)) were obtained.
The adhesive sheets (1) to (12) and (C1) to (C7) were subjected to a commercially available measuring machine (product name "MCR302", manufactured by Anton Pearl Co., Ltd.), and their dynamic viscoelasticity was measured under the following conditions. Then, from the measurement results, the storage elastic modulus G'at 25 ° C. and 1 Hz and the loss coefficient Tan δ at 50 ° C. and 1 Hz were obtained.
(Measurement condition)
Deformation mode: Torsion measurement frequency: 1Hz
Strain: 0.01 to 1% AUTO Set temperature rise rate: 3 ° C / min Measurement temperature: 25 to 50 ° C
Shape: Parallel plate 8.0 mmφ

<Performance evaluation (3): Compatibility>
Using a spectrophotometer (product name "U-3210 type self-recording spectrophotometer", manufactured by Hitachi, Ltd.), the adhesive sheet of performance evaluation (2) is irradiated with light having a wavelength of 500 nm, and its transmittance (%). ) Was measured, and compatibility was evaluated according to the following criteria.
◯: 85% or more ×: less than 85%

<Performance evaluation (4): Step followability>
A laminated film was prepared so that the film thickness of the pressure-sensitive adhesive composition after curing in the performance evaluation (2) was 100 μm, and the light peeling-treated polyester film was further peeled off. Instead, a 50 μm-thick polyester film (product name “Product name” "Cosmo Shine A-4300" (manufactured by Toyobo Co., Ltd.) was bonded with a 2 kg roller and allowed to stand for 2 hours. Next, a test piece of 8 cm × 8 cm was cut out from this piece, and a heavy peeling-treated polyester film was peeled off to prepare a single-sided adhesive sheet (Cosmoshine A-4300 / adhesive layer). A polyester film piece (5 cm x 5 cm x 50 μm) is placed on a glass plate (10 cm x 10 cm x 2 mm), and a single-sided adhesive sheet (adhesive layer / Cosmo Shine A-4300) (5 cm x 5 cm x 150 μm) is placed on top of it. Laminated body (Cosmo Shine A-4300 (50 μm thick) / Adhesive layer (100 μm thick) / Polyester film piece (50 μm thick) / Glass plate (2 mm thick)) (Laminated body (1) by stacking and adhering with a 2 kg roller -1) to (12-1) and (C1-1) to (C7-1)) were prepared.
The laminates (1-1) to (12-1) and (C1-1) to (C7-1) were treated in an autoclave under the conditions of 50 ° C., 0.5 MPa and 20 minutes, and then 25 ° C. and humidity 50. After allowing to stand for 24 hours under the condition of%, the evaluation was made under the conditions of 85 ° C., humidity 85% and 24 hours in a constant temperature and humidity chamber. The step followability of the adhesive layer in this state was visually evaluated according to the following criteria.
1: No floating is observed along each side of the polyester film piece and no bubbles are confirmed. 2: No floating is observed along each side of the polyester film piece, but up to 5 fine bubbles can be confirmed. 3: A slightly wide float is observed along each side of the polyester film piece, and up to 10 fine bubbles can be confirmed. 4: A wide float is observed along each side of the polyester film piece, and Not only fine bubbles but also multiple large bubbles can be confirmed.

<Performance evaluation (5): Haze value>
A laminated film was prepared so that the film thickness of the pressure-sensitive adhesive composition after curing in the performance evaluation (2) was 100 μm, and the light peeling-treated polyester film was further peeled off. Instead, a 50 μm-thick polyester film (product name “Product name” "Cosmo Shine A-4300" (manufactured by Toyobo Co., Ltd.) was bonded with a 2 kg roller and allowed to stand for 2 hours. Next, a test piece of 8 cm × 8 cm was cut out from this piece, and a heavy peeling-treated polyester film was peeled off to prepare a single-sided adhesive sheet (Cosmoshine A-4300 / adhesive layer). A single-sided adhesive sheet (adhesive layer / Cosmoshine A-4300) (5 cm x 5 cm x 150 μm) is placed on a glass plate (10 cm × 10 cm × 2 mm) and brought into close contact with a 2 kg roller to form a laminate (Cosmoshine A-). 4300 (50 μm thick) / adhesive layer (100 μm thick) / glass plate (2 mm thick)) (laminates (1-2) to (12-2) and (C1-2) to (C7-2)) were prepared. ..
The haze values of the laminates (1-2) to (12-2) and (C1-2) to (C7-2) can be measured with a commercially available measuring machine (product name "haze / transmittance meter HM-150", Co., Ltd. ) Murakami Color Technology Laboratory) was used for measurement in accordance with JIS K 7136: 2000. The obtained haze value is a value including the haze value of the base material (Cosmo Shine A-4300 and the glass plate).

<Performance evaluation (6): Haze value (after moisture resistance test)>
The haze values of the laminates (1-2) to (12-2) and (C1-2) to (C7-2) after being allowed to stand in a constant temperature and humidity chamber at a temperature of 85 ° C. and a humidity of 85% for 500 hours. , A commercially available measuring machine (product name "Haze / Transmittance Meter HM-150", manufactured by Murakami Color Technology Laboratory Co., Ltd.) was used for measurement in accordance with JIS K 7136: 2000. The obtained haze value is a value including the haze value of the base material (Cosmo Shine A-4300 and the glass plate).

<Performance evaluation (7): Adhesive strength>
The laminates (1-2) to (12-2) and (C1-2) to (C7-2) were allowed to stand for 24 hours under the conditions of 25 ° C. and 50% humidity. The adhesive strength (N / 25 mm) was measured by peeling the single-sided adhesive sheet (adhesive layer / Cosmo Shine A-4300) from the glass plate in the 180 ° direction at a speed of 300 mm / min. A commercially available machine (product name "Tensilon universal material tester", manufactured by AND Co., Ltd.) was used for the measurement.

<Performance evaluation (8): Durability (after moisture resistance test)>
The laminates (1-2) to (12-2) and (C1-2) to (C7-2) are allowed to stand in a constant temperature and humidity chamber at a temperature of 85 ° C. and a humidity of 85% for 500 hours, and then the adhesive layer is formed. The durability of the product was evaluated according to the following criteria.
◯: No peeling of the base material, misalignment of the adhesive layer position, air bubbles in the adhesive layer, or damage to the adhesive layer ×: Peeling of the base material, misalignment of the adhesive layer position, air bubbles in the adhesive layer, damage to the adhesive layer At least one defect has occurred

The meanings of the terms in Tables 3 and 4 are as follows.
* 1: The amount (% by mass) used in the table is a ratio when the total mass of the component (A), the component (B), and the component (C) is 100% by mass. Further, the mass% of the component (A) does not contain the 2-EHA solution or the IBXA solution. The 2-EHA solution and IBXA solution of the component (A) are contained in the mass% of 2-EHA and IBXA of the component (B).
* 2: The amount (% by mass) of the component (D) used is a ratio when the total mass of the component (A), the component (B), and the component (C) is 100% by mass.
2-EHA: 2-Ethylhexyl acrylate (Product name "2-ethylhexyl acrylate", manufactured by Mitsubishi Chemical Corporation)
ISTA: Isostearyl acrylate (product name "ISTA", manufactured by Osaka Organic Chemical Co., Ltd.)
BA: n-Butyl acrylate (Product name "Butyl acrylate", manufactured by Mitsubishi Chemical Corporation)
IBXA: Isobornyl acrylate (product name "IBXA", manufactured by Osaka Organic Chemical Industry Co., Ltd.)
HEA: 2-Hydroxyethyl acrylate (product name "HEA", manufactured by Osaka Organic Chemical Industry Co., Ltd.)
HPA: 2-Hydroxypropyl (meth) acrylate 4HBA: 4-Hydroxybutyl acrylate (Product name "4-HBA", manufactured by Osaka Organic Chemical Industry Co., Ltd.)
L200: 1-Hydroxycyclohexylphenyl ketone (product name "Luna200", manufactured by DKSH Japan K.K.)
TPO: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (product name "Speedcure TPO", manufactured by DKSH Japan K.K.)

Claims (8)

Polyurethane, which is a reaction product of (A) (a1) polyol, (a2) aliphatic polyisocyanate, (a3) hydroxyl group-containing mono (meth) acrylate, and (a4) hydroxyl group-containing photopolymerization initiator,
(B) (b1) An alkyl mono (meth) acrylate having a linear alkyl group having no alicyclic structure and having 4 or more and 18 or less carbon atoms, and a branched alkyl group having no alicyclic structure having 4 to 18 carbon atoms. One or more alkyl mono (meth) acrylates selected from the following alkyl mono (meth) acrylates and (b2) alkyl mono (meth) acrylates having an alicyclic structure and having 6 or more and 15 or less carbon atoms. When,
(C) Containing mono (meth) acrylate containing a primary hydroxyl group,
The component (A3) is introduced in an amount of 10 mol% or more and 90 mol% or less with respect to the isocyanate group at the end of the urethane prepolymer composed of the component (a1) and the component (a2), and (a4). Ingredients are introduced in an amount of 10 mol% or more and 90 mol% or less.
Active energy ray-curable pressure-sensitive adhesive composition. When the total of the component (A), the component (B), and the component (C) is 100% by mass, the component (A) is 20% by mass or more and 70% by mass or less, and the component (B) is 25% by mass. The active energy ray-curable pressure-sensitive adhesive composition according to claim 1, wherein the content is 75% by mass or more and the component (C) is 5% by mass or more and 55% by mass or less. (A1) The active energy ray-curable pressure-sensitive adhesive composition according to claim 1 or 2, wherein the number average molecular weight of the components is 700 or more and 10,000 or less. The active energy ray-curable pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the component (a3) is a hydroxyl group-containing mono (meth) acrylate having 5 or more and 10 or less carbon atoms. The active energy ray-curable pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the weight average molecular weight of the component (A) is 10,000 or more and 90,000 or less. A cured product of the active energy ray-curable pressure-sensitive adhesive composition according to any one of claims 1 to 5. The cured product according to claim 6, wherein the storage elastic modulus G'at 25 ° C. and 1 Hz is 8 × 10 ⁴ Pa or more, and the loss coefficient Tan δ at 50 ° C. and 1 Hz is 0.4 or more. An adhesive sheet having the cured product according to claim 6 or 7 on at least one surface of the substrate surface.