KR20210148930A - Pressure Sensitive Adhesive Sheet, Adherend with Pressure Sensitive Adhesive Sheet, and Method for Using Pressure Sensitive Adhesive Sheet - Google Patents

Abstract

Provided is an adhesive sheet having good wettability to an adherend and adhered to the adherend with an adhesive force not easily peeled off before emission of active energy rays, and easily peeled off from the adherend after emission of active energy rays. According to the present invention, the adhesive sheet comprises an adhesive layer. The adhesive layer is a coated material of an adhesive comprising: at least one non-radically polymerizable active hydrogen group-containing compound (HC) having a plurality of active hydrogen groups and not having a (meth)acryloyl group; at least one radical polymerizable monomer (M) including at least one radical polymerizable active hydrogen group-containing monomer (MH) having at least one active hydrogen group and at least two (meth)acryloyl groups; a polyfunctional isocyanate compound (I); and a gas generation agent (G) generating gas by emission of active energy rays. The adhesive strength of the adhesive layer is 0.1 to 26 gf/25 mm.

Description

Pressure Sensitive Adhesive Sheet, Adherend with Pressure Sensitive Adhesive Sheet, and Method for Using Pressure Sensitive Adhesive Sheet}

This application claims priority on the basis of Japanese Patent Application No. 2020-095352 for which it applied on June 1, 2020, and takes in all the indications here.

The present invention relates to a pressure-sensitive adhesive sheet, an adherend to which the pressure-sensitive adhesive sheet is attached, and a method of using the pressure-sensitive adhesive sheet.

DESCRIPTION OF RELATED ART Conventionally, the adhesive sheet in which the adhesive layer was formed on the base material sheet is widely used as a surface protection sheet of various members. Examples of the pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, and a urethane pressure-sensitive adhesive. Although the acrylic pressure-sensitive adhesive is excellent in adhesive strength, the re-peelability after being adhered to the adherend is not good because of its high adhesive strength. Silicone pressure-sensitive adhesives tend to cause contamination on adherends, and silicone resins having a relatively low molecular weight may volatilize and adsorb to the surface of devices such as electronic devices, which may cause problems. On the other hand, the urethane-based pressure-sensitive adhesive has good adhesion to the adherend, and is also relatively excellent in re-peelability and is difficult to volatilize.

In this specification, unless otherwise specified, "adhesive" is a pressure-sensitive adhesive having re-peelability (re-peelable pressure-sensitive adhesive), and "adhesive sheet" is a pressure-sensitive adhesive sheet having re-peelability (re-peelable pressure-sensitive adhesive sheet).

As a method for producing a urethane-based pressure-sensitive adhesive, a method using a hydroxyl-terminated urethane prepolymer and a polyfunctional isocyanate compound, which are reaction products of an active hydrogen group-containing compound such as polyol and polyisocyanate, and a polyol and polyol without using a hydroxyl-terminated urethane prepolymer There is a method (one-shot method) in which the functional isocyanate compound is reacted at once.

A general method for producing a pressure-sensitive adhesive sheet includes a coating step of coating the pressure-sensitive adhesive on a base sheet, a heating step of heating and drying the formed coating layer to form an adhesive layer, and winding the obtained pressure-sensitive adhesive sheet around a roll core to form a pressure-sensitive adhesive sheet roll. A winding process to do, and a curing process for curing the pressure-sensitive adhesive sheet roll are included.

Japanese Patent Laid-Open No. 2015-124301 Japanese Patent Laid-Open No. 2016-28020

Panel displays such as liquid crystal displays (LCDs) and organic electroluminescence displays (OELDs), and touch panel displays combining a panel display and a touch panel are televisions (TVs), personal computers (PCs), mobile phones, and portable information. It is widely used in electronic devices such as terminals.

The urethane pressure-sensitive adhesive sheet is a panel display and touch panel display such as LCD, and a substrate manufactured or used in these manufacturing processes (a glass substrate and an ITO/glass substrate in which an ITO (indium tin oxide) film is formed on the glass substrate, etc.) and optical It is suitably used as a surface protection sheet|seat, such as a member.

In manufacturing processes, such as panel displays, such as LCD, and a touch panel display, it is preferable for the to-be-adhered body with an adhesive sheet to be able to convey at high speed to the processing part which performs a required process for productivity improvement. For example, the automatic high-speed conveyance which adsorb|sucks the to-be-adhered body with an adhesive sheet from the adhesive sheet side using a vacuum suction member, lifts it, and conveys to a desired position is examined.

In the said automatic high-speed conveyance, it is preferable that the to-be-adhered body with an adhesive sheet has sufficient adhesive force so that an adhesive sheet will not peel from a to-be-adhered body while being adsorb|sucked by the vacuum suction member. On the other hand, in the to-be-adhered body to which the adhesive sheet has completed the required process, it is preferable that the adhesive sheet has comparatively low adhesive force so that the adhesive sheet can be peeled at high speed. It is preferable that the pressure-sensitive adhesive sheet can be easily peeled off from the adherend to which the pressure-sensitive adhesive sheet has been adhered after the necessary steps, and it is more preferable that the pressure-sensitive adhesive sheet is naturally peeled off.

Patent documents 1 and 2 are mentioned as a related art of this invention.

Patent Document 1 relates to an acrylic adhesive tape (claim 1).

The adhesive tape of patent document 1 WHEREIN: The adhesive layer can contain a radically polymerizable polyfunctional oligomer or a monomer (paragraph 0044). In the adhesive layer containing a radically polymerizable polyfunctional oligomer or monomer, an oligomer or a monomer may superpose|polymerize by irradiation of active energy rays, such as an ultraviolet-ray, and adhesive force may fall.

The adhesive tape of patent document 1 WHEREIN: The adhesive layer can contain gas generating agents, such as an azo compound, an azide compound, a tetrazole compound and its salt, and a bistetrazole compound (paragraph 0037). When the pressure-sensitive adhesive layer contains a gas generating agent, gas can be generated from the gas generating agent by irradiation with active energy rays such as ultraviolet rays.

In the adhesive tape described in Patent Document 1, while reducing the adhesive strength of the adhesive layer by polymerization of oligomers or monomers by irradiation with active energy rays such as ultraviolet rays, and simultaneously generating gas from the gas generator by irradiation with active energy rays such as ultraviolet rays The adhesive tape can be easily peeled off from a to-be-adhered body.

Patent Document 2 discloses an adhesive composition containing an adhesive component and a tetrazole compound-basic azo compound complex formed by reacting a tetrazole compound with a basic azo compound (Claim 1).

Patent Document 2 discloses an adhesive tape having an adhesive layer made of the above adhesive composition on one or both surfaces of a substrate (claim 7).

In the item of [Example], only the acrylic adhesive composition and adhesive tape were manufactured.

When the adhesive component contains a curable adhesive, the curable adhesive may contain a radical polymerizable polyfunctional oligomer or monomer (Paragraph 0031). In the adhesive layer containing the radically polymerizable polyfunctional oligomer or monomer, the oligomer or the monomer may be superposed|polymerized by irradiation of active energy rays, such as an ultraviolet-ray, and adhesive force may fall.

When the adhesive component contains a curable adhesive, the tetrazole compound-basic azo compound complex generates gas by irradiation with active energy rays such as ultraviolet rays, so that the adhesive tape can be easily peeled off from the adherend (Paragraph 0022) .

Patent Document 1 relates to an acrylic adhesive tape, not to a urethane adhesive sheet.

In the item of [Example] of patent document 2, only the acrylic adhesive composition and adhesive tape are manufactured, and patent document 2 does not disclose specific manufacture of a urethane type adhesive sheet.

In general, since a urethane-based pressure-sensitive adhesive has high wettability to an adherend as compared with an acrylic pressure-sensitive adhesive, it is more difficult to peel from the adherend.

The present invention has been made in view of the above circumstances, and has good wettability to the adherend before irradiation with active energy rays, has re-peelability that can be re-sticked to the adherend, and is not easily peeled off from the adherend. An object of the present invention is to provide a urethane-based pressure-sensitive adhesive sheet that can be pasted by adhesive force and can be easily peeled off from an adherend after irradiation with an active energy ray.

The pressure-sensitive adhesive sheet of the present invention,

A pressure-sensitive adhesive sheet comprising: a base sheet; and an adhesive layer formed on the base sheet and having active energy ray curability;

The adhesive layer is

At least one non-radical polymerizable active hydrogen group-containing compound (HC) having a plurality of active hydrogen groups and not having a (meth)acryloyl group;

At least one radical polymerizable monomer (M) comprising at least one radical polymerizable active hydrogen group-containing monomer (MH) having at least one active hydrogen group and at least two (meth)acryloyl groups;

A polyfunctional isocyanate compound (I), and

It is a coating dried product of an adhesive containing a gas generator (G) that generates gas by irradiation with active energy rays,

The said adhesive layer is an adhesive sheet whose adhesive force is 0.1-26gf/25mm measured on the conditions of a peeling speed of 0.3 m/min and a peeling angle of 180 degrees using a tensile tester based on JIS Z0237.

The to-be-adhered body to which the adhesive sheet of this invention was affixed is the thing by which the said adhesive sheet of this invention was stuck on the to-be-adhered body.

The use method of the 1st adhesive sheet of this invention is,

A step of adhering the pressure-sensitive adhesive sheet of the present invention to the surface of an adherend;

and irradiating an active energy ray to the pressure-sensitive adhesive sheet pasted on the surface of the adherend to reduce the adhesive strength of the pressure-sensitive adhesive sheet.

The use method of the 2nd adhesive sheet of this invention is,

A step of adhering the pressure-sensitive adhesive sheet of the present invention to the surface of an adherend;

By irradiating an active energy ray to the pressure-sensitive adhesive sheet adhered to the surface of the adherend to lower the adhesive strength of the pressure-sensitive adhesive sheet, the self-weight of the pressure-sensitive adhesive layer relative to the acrylic resin plate after irradiation with active energy rays, measured by the following method (Heavy) The step of peeling the adhesive sheet in which the adhesive force was lowered from the adherend by setting the adhesion time to 30 seconds or longer is included.

Both ends of the pressure-sensitive adhesive sheet having a width of 100 mm and a length of 200 mm are held with both hands in the longitudinal direction, and the pressure-sensitive adhesive sheet is curved so that the pressure-sensitive adhesive layer faces outward to match the both ends of the pressure-sensitive adhesive sheet. In this state, the pressure-sensitive adhesive layer at the center of the pressure-sensitive adhesive sheet is brought into contact with the acrylic resin plate. In this state, release both hands holding the both ends. After releasing both hands, the time until the entire adhesive layer adheres to the acrylic resin plate is measured as the self-weight attachment time.

According to the present invention, before irradiation with active energy rays, it has good wettability to the adherend, has re-peelability to the adherend, and can be adhered to the adherend with an adhesive force that is not easily peeled off, After irradiation with an active energy ray, it is possible to provide a urethane-based pressure-sensitive adhesive sheet that can be easily peeled off from an adherend.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the adhesive sheet of 1st Embodiment which concerns on this invention,
2 : is a schematic sectional drawing of the adhesive sheet of 2nd Embodiment which concerns on this invention.

The present invention relates to a urethane-based pressure-sensitive adhesive sheet having a base sheet and an adhesive layer formed on at least one surface of the base sheet.

In the present invention, the pressure-sensitive adhesive layer is composed of a dried product of the urethane pressure-sensitive adhesive, and contains a reaction product of at least one active hydrogen group-containing compound and at least one polyfunctional isocyanate compound.

In this invention, an adhesive layer has active energy ray sclerosis|hardenability.

The pressure-sensitive adhesive sheet of the present invention is manufactured or used in panel displays such as liquid crystal displays (LCDs) and organic electroluminescence displays (OELDs), and touch panel displays in which the panel displays and touch panels are combined, and their manufacturing processes It is suitable as a surface protection sheet for substrates to be used (a glass substrate and an ITO/glass substrate in which an ITO (indium tin oxide) film is formed on the glass substrate, etc.) and optical members.

In the present specification, the term "adhesive with an adhesive sheet" refers to a glass substrate, an ITO/glass substrate on which an ITO (indium tin oxide) film is formed on the glass substrate, and an adhesive sheet on the surface of an adherend such as an optical member. It is a laminated body.

[adhesive]

The adhesive, which is a material of the adhesive layer, is

At least one non-radically polymerizable active hydrogen group-containing compound (HC) having a plurality of active hydrogen groups and not having a (meth)acryloyl group;

At least one radical polymerizable monomer (M) comprising at least one radical polymerizable active hydrogen group-containing monomer (MH) having at least one active hydrogen group and at least two (meth)acryloyl groups;

A polyfunctional isocyanate compound (I), and

The gas generating agent (G) which generate|occur|produces gas by irradiation of an active energy ray is included.

The active hydrogen group-containing compound (HC) is a non-radically polymerizable compound that has a plurality of active hydrogen groups and does not have a (meth)acryloyl group.

Examples of the active hydrogen group include a hydroxyl group (hydroxy group), a mercapto group, and an amino group (unless otherwise specified in this specification, an amino group includes an imino group). Examples of the active hydrogen group-containing compound (HC) include a polyol having a plurality of hydroxyl groups, a polyamine having a plurality of amino groups, an amino alcohol having an amino group and a hydroxyl group, and a polythiol having a plurality of mercapto groups. A non-polymer may be sufficient as these active hydrogen group containing compounds (HC), and a polymer may be sufficient as them. These can be used 1 type or 2 or more types.

In particular, polyols are preferred. Since polyamines and polythiols have high reactivity and short pot life, when using them, it is preferable to use them together with polyols. In addition, when the active hydrogen group of the polyol is a secondary hydroxyl group, since the initial curability of the urethane-based pressure-sensitive adhesive is not improved, from the viewpoint of pot life and initial curability, the polyol preferably contains a primary hydroxyl group having moderate reactivity.

(Hydroxy-terminated urethane prepolymer (UPH))

The active hydrogen group-containing compound (HC) is preferably a hydroxyl group-terminated urethane prepolymer (UPH), which is a reaction product obtained by copolymerizing at least one active hydrogen group-containing compound (HX) and at least one polyisocyanate (N). The copolymerization reaction may be carried out in the presence of one or more catalysts, if necessary. One or more types of solvents can be used for a copolymerization reaction as needed. The hydroxyl-terminated urethane prepolymer (UPH) does not contain a (meth)acryloyl group.

<Active hydrogen group-containing compound (HX)>

The active hydrogen group-containing compound (HX), which is a raw material of the hydroxyl-terminated urethane prepolymer (UPH), is a compound having a plurality of active hydrogen groups and not having a (meth)acryloyl group.

Examples of the active hydrogen group include a hydroxyl group (hydroxy group), a mercapto group, and an amino group (unless otherwise specified in this specification, an amino group includes an imino group). Examples of the active hydrogen group-containing compound (HX) include a polyol having a plurality of hydroxyl groups, a polyamine having a plurality of amino groups, an amino alcohol having an amino group and a hydroxyl group, and a polythiol having a plurality of mercapto groups. Such an active hydrogen group-containing compound (HX) may be a non-polymer or a polymer. These can be used 1 type or 2 or more types.

In particular, polyols are preferred. Since polyamines and polythiols have high reactivity with polyisocyanates, attention must be paid to controlling the reaction when using them. In addition, the reaction product of polyamine and polyisocyanate has a greater cohesive force than the reaction product of polyol and polyisocyanate and tends to increase in viscosity. It is preferable to do

Examples of the polyol that can be used as the active hydrogen group-containing compound (HX) include polyester polyol, polyether polyol, polyacrylic polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol. Among them, polyester polyols, polyether polyols, and combinations thereof are preferred. The at least one active hydrogen group-containing compound (HX) preferably contains a polyether polyol.

As the polyester polyol that can be used as the active hydrogen group-containing compound (HX), a known one can be used. As a polyester polyol, the compound (esterified product) obtained by the esterification reaction of 1 or more types of polyol components and 1 or more types of acid components is mentioned, for example.

As the polyol component of the raw material, ethylene glycol (EG), propylene glycol (PG), diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2 -Butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3- hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, and pentaerythritol can be heard

As the acid component of the raw material, succinic acid, methylsuccinic acid, adipic acid, pimeric acid, azelaic acid, sebacic acid, 1,12-dodecanoic acid, 1,14-tetradecanoic acid, dimer acid, 2-methyl-1,4- Cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and acid anhydrides thereof can be heard

As the polyether polyol that can be used as the active hydrogen group-containing compound (HX), a publicly known one can be used. Examples of the polyether polyol include compounds (addition polymers) obtained by addition polymerization of one or more oxirane compounds using an active hydrogen group-containing compound having a plurality of active hydrogen groups as an initiator.

As an initiator, a hydroxyl-containing compound, amines, etc. are mentioned. Specific examples thereof include bifunctional initiators such as ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, butylethylpentanediol, N-aminoethylethanolamine, isophoronediamine, and xylenediamine; trifunctional initiators such as glycerin, trimethylolpropane, and triethanolamine; A tetrafunctional initiator, such as pentaerythritol, ethylenediamine, and aromatic diamine, etc. are mentioned.

Examples of the oxirane compound include alkylene oxides (AO) such as ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO); Tetrahydrofuran (THF), etc. are mentioned.

As the polyether polyol, an alkylene oxide adduct (also referred to as polyoxyalkylene polyol) of an active hydrogen-containing compound is preferable. Among them, bifunctional polyether polyols such as polyalkylene glycols such as polyethylene glycol (PEG), polypropylene glycol (PPG), PPG (PPG-EO) to which ethylene oxide (EO) is added to the terminal, and polytetramethylene glycol; Trifunctional polyether polyols, such as an alkylene oxide adduct of glycerol, etc. are preferable.

Examples of the polyamine usable as the active hydrogen group-containing compound (HX) include ethylene diamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, and 1,6- Hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16 - Hexadecanediamine, hexamethylene diamine, trimethylhexamethylenediamine, iminobispropylamine, methyliminobispropylamine, 1,5-diamino-2-methylpentane, isophoronediamine, 1,3-bisaminomethylcyclohexane , 1-cyclohexylamino-3-aminopropane, 3-aminomethyl-3,3,5-trimethyl-cyclohexylamine, norbornane skeleton dimethyleneamine, metaxylenediamine (MXDA), hexamethylenediamine carbamate aliphatic polyamines such as , diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine; 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 3,3'-diamino Diphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,4-diaminophenol, 2,5-diaminophenol , o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,3-tolylenediamine, 2,4-tolylenediamine, 2,5-tolylenediamine, 2,6-tolylenediamine , 3,4-tolylenediamine, and aromatic polyamines such as diethyltoluenediamine; etc.

Examples of the amino alcohol that can be used as the active hydrogen group-containing compound (HX) include monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, tri(hydroxymethyl)aminomethane, and 2-amino- monoamines having a hydroxyl group such as 2-ethyl-1,3-propanediol; diamines having a hydroxyl group such as N-(2-hydroxypropyl)ethanolamine; and the like.

Examples of the polythiol that can be used as the active hydrogen group-containing compound (HX) include methanedithiol, 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, and 1,2-benzenedithiol. ol, 1,3-benzenedithiol, 1,4-benzenedithiol, 1,10-decanedithiol, 1,2-ethanedithiol, 1,6-hexanedithiol, 1,9-nonanedithiol, 1,8-octane dithiol 1,5-pentanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, toluene-3,4-dithiol, 3,6-dichloro-1,2- Benzene dithiol, 1,5-naphthalenedithiol, 1,2-benzene dimanethiol, 1,3-benzene dimanethiol, 1,4-benzene dimanethiol, 4,4'-thiobisbenzenethiol, 2 ,5-dimercapto-1,3,4-thiadiazole, 1,8-dimercapto-3,6-dioxaoctane, 1,5-dimercapto-3-thiapentane, 2-di- n-butylamino-4,6-dimercapto-s-triazine, and thiol group-terminated polymers (such as polysulfide polymers) are mentioned.

The at least one active hydrogen group-containing compound (HX) may include a bifunctional active hydrogen group-containing compound and/or a trifunctional or more active hydrogen group-containing compound. In general, the bifunctional active hydrogen group-containing compound has two-dimensional crosslinkability and can impart appropriate flexibility to the pressure-sensitive adhesive layer. The trifunctional or more active hydrogen group-containing compound has three-dimensional crosslinking and can impart appropriate hardness to the adhesive layer. By selecting the number of functional groups (the number of active hydrogen groups) of each active hydrogen group-containing compound (HX), characteristics such as adhesive force, cohesive force, and re-peelability of the urethane-based pressure-sensitive adhesive can be adjusted. Depending on the use and the like, the number of functional groups in each material can be selected so that properties such as adhesive force, cohesive force, and re-peelability are within a preferable range.

Since it is easy to make adhesive force and re-peelability compatible, it is preferable that 1 or more types of active hydrogen group containing compound (HX) contains a bifunctional active hydrogen group containing compound and a trifunctional or more functional active hydrogen group containing compound.

The number average molecular weight (Mn) of the active hydrogen group-containing compound (HX) is not particularly limited. Since the adhesive force and wet diffusivity of an adhesion layer become suitable, Mn of an active hydrogen group containing compound (HX) becomes like this. Preferably it is 50-20000, More preferably, it is 100-7000, Especially preferably, it is 400-5000.

<Polyisocyanate (N)>

A well-known thing can be used as polyisocyanate (N) which is a raw material of a hydroxyl-terminated urethane prepolymer (UPH), An aromatic polyisocyanate, an aliphatic polyisocyanate, an alicyclic polyisocyanate, etc. are mentioned.

The polyisocyanate (N) can be used 1 type or 2 or more types. The number in particular of the functional group of polyisocyanate (N) is not restrict|limited, It is preferable that it is bifunctional. That is, it is preferable that 1 or more types of polyisocyanate (N) mainly contains a bifunctional polyisocyanate, It is more preferable that 1 or more types of polyisocyanate (N) is a bifunctional polyisocyanate.

Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4′,4″-triphenylmethanetriisocyanate, ω,ω′-diisocyanate-1,3-dimethylbenzene, ω,ω′-diisocyanate-1,4-dimethylbenzene, ω, omega'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylene diisocyanate, 1,3-tetramethylxylene diisocyanate, etc. are mentioned.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, and 1,3-butylene diisocyanate. isocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate, etc. are mentioned.

Examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, and methyl-2,4-cyclohexanedi. isocyanate, methyl-2,6-cyclohexanediisocyanate, 4,4'-methylenebis(cyclohexylisocyanate), 1,4-bis(isocyanatemethyl)cyclohexane, etc. are mentioned.

In addition, as polyisocyanate, the trimethylol propane adduct body, a biuret body, an allophanate body, and a trimer (this trimer contains an isocyanurate ring) etc. of the said polyisocyanate are mentioned.

The preferred raw material mixing ratio of the hydroxyl-terminated urethane prepolymer (UPH) is as follows.

The ratio (NCO/H ratio) of the number of moles of isocyanate groups (NCO) of the polyisocyanate (N) to the total number of moles of active hydrogen groups (H) of the various active hydrogen group-containing compounds (HX) is 0.20 to 0.95 , It is preferable to determine the raw material mixing ratio so that it is more preferably 0.40 to 0.80. The closer the NCO/H ratio is to 1, the easier it tends to gel when synthesizing a hydroxyl-terminated urethane prepolymer (UPH). When the NCO/H ratio is 0.95 or less, gelation at the time of synthesizing a hydroxyl-terminated urethane prepolymer (UPH) can be effectively suppressed.

<Catalyst>

For polymerization of hydroxyl-terminated urethane prepolymer (UPH), one or more catalysts can be used as needed. A well-known thing can be used as a catalyst, A tertiary amine type compound, an organometallic compound, etc. are mentioned.

Examples of the tertiary amine compound include triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU).

Examples of the organometallic compound include a tin-based compound and a non-tin-based compound.

Examples of the tin compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, and dioctyltin dilaurate. , dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.

Examples of the non-tin-based compound include titanium-based compounds such as dibutyl titanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride; lead systems such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron systems such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt type, such as cobalt benzoate and cobalt 2-ethylhexanoate; Zinc types, such as zinc naphthenate and zinc 2-ethylhexanoate; Zirconium systems, such as zirconium naphthenate, are mentioned.

The kind and addition amount of the catalyst can be appropriately designed within the range in which the reaction proceeds favorably.

When several types of active hydrogen group-containing compounds (HX) having different reactivity are used in combination, there is a fear that, due to the difference in reactivity, poor polymerization stability or cloudiness of the reaction solution is likely to occur in a single catalyst system. In this case, by using two or more types of catalysts, it becomes easy to control reaction (for example, reaction rate, etc.), and the said problem can be solved. In a system in which several types of active hydrogen group-containing compounds (HX) having different reactivity are used in combination, it is preferable to use two or more types of catalysts. A combination of two or more catalysts is not particularly limited, and examples thereof include tertiary amine/organometallic, tin/non-tin, and tin/tin. Preferred are tin-based/tin-based, more preferably dioctyltin dilaurate and tin 2-ethylhexanoate.

The mass ratio of tin 2-ethylhexanoate to dioctyltin dilaurate (tin 2-ethylhexanoate/dioctyltin dilaurate) is not particularly limited, preferably greater than 0 and less than 1, more preferably 0.2 ~0.8. When the mass ratio is less than 1, the catalyst activity is well balanced, gelation and cloudiness of the reaction solution are effectively suppressed, and polymerization stability is further improved.

The amount of one or more catalysts used is not particularly limited, and is preferably 0.01 to 1.0 mass % with respect to the total amount of one or more active hydrogen group-containing compounds (HX) and one or more polyisocyanates (N).

<solvent>

For polymerization of hydroxyl-terminated urethane prepolymer (UPH), one or more solvents can be used as needed. A well-known thing can be used as a solvent, Methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, etc. are mentioned. Ethyl acetate, toluene, etc. are especially preferable from points, such as the solubility of a hydroxyl-terminated urethane prepolymer (UPH), and the boiling point of a solvent.

<Polymerization method of hydroxyl-terminated urethane prepolymer (UPH)>

The polymerization method in particular of a hydroxyl-terminated urethane prepolymer (UPH) is not restrict|limited, Well-known polymerization methods, such as a block polymerization method and a solution polymerization method, are applicable.

As the polymerization sequence of the hydroxyl-terminated urethane prepolymer (UPH),

Step 1) at least one active hydrogen group-containing compound (HX), at least one polyisocyanate (N), if necessary, at least one catalyst, and, if necessary, at least one solvent, in a batch to prepare a flask;

Step 2) At least one active hydrogen group-containing compound (HX), optionally at least one catalyst, and optionally at least one solvent are prepared in a flask, and at least one polyisocyanate (N) is added dropwise thereto (滴下) the order of addition, and the like.

When several types of active hydrogen group-containing compounds (HX) and/or polyisocyanates (N) are used, the reaction can be carried out in several steps.

The reaction temperature in the case of using a catalyst is preferably less than 100°C, more preferably 50 to 95°C, and particularly preferably 60 to 85°C. If the reaction temperature is 100 DEG C or higher, control of the reaction rate and polymerization stability becomes difficult, and there is a fear that it becomes difficult to produce a hydroxyl-terminated urethane prepolymer (UPH) having a desired molecular weight. The reaction temperature when no catalyst is used is preferably 100°C or higher, more preferably 110°C or higher.

(Polyfunctional isocyanate compound (I))

As the polyfunctional isocyanate compound (I), a known compound can be used, and the compound exemplified as the polyisocyanate (N), which is a raw material of a hydroxyl-terminated urethane prepolymer (UPH) (specifically, an aromatic polyisocyanate, an aliphatic polyisocyanate, an aromatic polyisocyanate) isocyanates, cycloaliphatic polyisocyanates, and their trimethylol propane adduct/biuret/allophanate/trimer) can be used.

The polyfunctional isocyanate compound (I) can be used 1 type or 2 or more types. The number in particular of the functional group of polyfunctional isocyanate compound (I) is not restrict|limited, It is preferable that it is trifunctional or more. That is, the at least one polyfunctional isocyanate compound (I) preferably mainly contains a trifunctional or higher polyisocyanate, and more preferably the at least one polyfunctional isocyanate compound (I) is a trifunctional or higher polyisocyanate.

(Radically polymerizable monomer (M))

The adhesive which is a material of an adhesive layer contains 1 or more types of radically polymerizable monomer (M).

A radically polymerizable monomer (M) is a material which polymerization-hardens by irradiation of active energy rays, such as an ultraviolet-ray and an electron beam, in presence of a radical polymerization initiator (RI) as needed. It is preferable that a radically polymerizable monomer (M) is ultraviolet curable hardening by ultraviolet irradiation.

In the present specification, unless otherwise specified, ultraviolet (hereinafter, it can be simply abbreviated as "UV") is "irradiated from a high-pressure mercury lamp that generates ultraviolet rays with a peak wavelength in the range of 250 to 440 nm. ) is the light that becomes '.

When an adherend to which the adhesive sheet is attached is irradiated with active energy rays, one or more radical polymerizable monomers (M) contained in the adhesive layer are polymerized and cured to lower the adhesive strength and wet diffusion properties of the adhesive layer, It becomes easy to peel an adhesive sheet.

When the active hydrogen group-containing compound of the main component has a (meth)acryloyl group like the radically polymerizable monomer (M), the reactivity of the adhesive layer becomes too high, and a small amount of light contained in ambient light such as fluorescent light and sunlight The reaction starts and proceeds easily by irradiation with ultraviolet rays, and there is a fear that the adhesive force of the adhesive layer is lowered. It is not preferable that the adhesive strength of the adhesive layer is lowered by irradiation of a small amount of ultraviolet light contained in ambient light during vacuum adsorption transport of the adherend or the like.

In the present invention, a non-radically polymerizable active hydrogen group-containing compound (HC) having no (meth)acryloyl group (preferably hydroxyl-terminated urethane prepolymer (UPH)) is used as the active hydrogen group-containing compound as the main component, The crosslinking reaction due to irradiation of a small amount of ultraviolet light contained in ambient light can be suppressed, and the adherend can be suppressed from peeling off from the pressure-sensitive adhesive sheet during vacuum adsorption transport of the adherend.

In the present invention, the at least one radical polymerizable monomer (M) includes at least one radical polymerizable active hydrogen group-containing monomer (MH) having at least one active hydrogen group and at least two (meth)acryloyl groups. and one or more other radically polymerizable monomers (MO), if necessary.

Examples of the active hydrogen group contained in the active hydrogen group-containing compound (MH) include a hydroxyl group (hydroxy group), a mercapto group, and an amino group (in this specification, unless otherwise specified, the amino group includes an imino group). and a hydroxyl group and amino are preferred, and a hydroxyl group is particularly preferred.

In this specification, "(meth)acryloyl group" means an acryloyl group and a methacryloyl group.

At least one non-radically polymerizable active hydrogen group-containing compound (HC) and at least one radical polymerizable active hydrogen group-containing monomer (MH) can react with the polyfunctional isocyanate compound (I). The adhesive layer may contain these reaction products.

One or more radically polymerizable, active hydrogen group-containing monomers (MH) can bond to a urethane resin through a polyfunctional isocyanate compound (I) during polymerization, and curing of the adhesive layer, and consequent decrease in adhesive strength and wet diffusion It can cause the deterioration of sex more effectively.

The at least one active hydrogen group-containing monomer (MH) preferably contains at least one trifunctional or more active hydrogen group-containing monomer (MHT) having three or more (meth)acryloyl groups. In this case, a crosslinking reaction proceeds during radical polymerization, which can effectively cause hardening of the adhesive layer, consequently lowering of adhesive force and lowering of wettability.

Since the above-mentioned effect becomes more effective, the number of (meth)acryloyl groups in the active hydrogen group-containing monomer (MH) is more preferably 4 or more, particularly preferably 5 or more.

That is, it is more preferable that at least one active hydrogen group-containing monomer (MH) contains at least one tetrafunctional or higher active hydrogen group-containing monomer (MHQ) having four or more (meth)acryloyl groups. It is particularly preferred that the at least one active hydrogen group-containing monomer (MH) contains at least one pentafunctional or higher active hydrogen group-containing monomer (MHF) having at least 5 (meth)acryloyl groups.

As the active hydrogen group-containing monomer (MH) having at least one active hydrogen group and two (meth)acryloyl groups, for example, glycerin diacrylate, glycerin dimethacrylate, and 2-hydroxy-3-acryl group Royloxypropyl methacrylate etc. are mentioned. These can be used 1 type or 2 or more types.

As the active hydrogen group-containing monomer (MH) having at least one active hydrogen group and at least three (meth)acryloyl groups, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritoltri( and meth)acrylate, dipentaerythritol tetra(meth)acrylate, and dipentaerythritol penta(meth)acrylate. These can be used 1 type or 2 or more types.

The one or more radically polymerizable monomers (M) may contain one or more other radically polymerizable monomers (MO) other than the active hydrogen group-containing monomer (MH) as needed. As a radically polymerizable monomer (MO), it has a 2 or more (meth)acryloyl group, and the compound which does not have an active hydrogen group is mentioned.

It is preferable that 1 or more types of other radically polymerizable monomer (MO) contains 1 or more types of trifunctional or more than radically polymerizable monomer (MOT) which has 3 or more (meth)acrylo groups. In this case, a crosslinking reaction proceeds during radical polymerization, which can effectively cause hardening of the adhesive layer, and thus a decrease in adhesive strength and a decrease in wet diffusivity.

Since the said effect becomes more effective, the number of (meth)acryloyl groups in a radically polymerizable monomer (MO) becomes like this. More preferably, it is 4 or more, Especially preferably, it is 5 or more.

That is, it is more preferable that 1 or more types of radically polymerizable monomer (MO) contains 1 or more types of tetrafunctional or more than radically polymerizable monomers (MOQ) which have 4 or more (meth)acryloyl groups. It is especially preferable that 1 or more types of radically polymerizable monomer (MO) contains 1 or more types of pentafunctional or more than radically polymerizable monomer (MOF) which has 5 or more (meth)acryloyl groups.

As the radically polymerizable monomer (MO) having two (meth)acryloyl groups and not having an active hydrogen group, for example, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylic Rate, ethoxylated bisphenol A dimethacrylate, tricyclodecanedimethanol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate acrylate, and neopentyl glycol dimethacrylate. These can be used 1 type or 2 or more types.

As a radically polymerizable monomer (MO) which has three or more (meth)acryloyl groups and does not have an active hydrogen group, for example, trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, ethylene oxide Modified trimethylolpropane tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, caprolactone modified tris(acryloxyethyl)isocyanurate, trimethyl Olethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, and 1,2,3-cyclohexane Ester compounds of polyhydric alcohols and (meth)acrylic acid, such as tetra (meth)acrylate; Polyurethane poly(meth)acrylate, polyester poly(meth)acrylate, polyether poly(meth)acrylate, polyacrylic poly(meth)acrylate, polyalkyd poly(meth)acrylate, polyepoxy poly(meth) ) acrylate, polyspiroacetal poly (meth) acrylate, polybutadiene poly (meth) acrylate, polythiol polyene poly (meth) acrylate, polyfunctional poly (meth) acrylate, such as poly (meth) acrylate ) an acrylate compound, and the like. These can be used 1 type or 2 or more types.

The total amount of one or more pentafunctional or more radically polymerizable monomers relative to the total amount of one or more radically polymerizable monomers (M) because it is possible to more effectively cause curing of the adhesive layer, and consequent decrease in adhesive strength and wet diffusivity Silver, Preferably it is 20-100 mass %, More preferably, 40-100 mass %, More preferably, it is 60-100 mass %, Especially preferably, 70 mass - 100 mass %, Most preferably, 80 mass - 100 mass % mass %.

The "one or more pentafunctional or more radically polymerizable monomers" as used herein includes one or more pentafunctional or more active hydrogen group-containing monomers (MHF) and/or one or more pentafunctional or more radically polymerizable monomers (MOF).

Since it can more effectively cause curing of the pressure-sensitive adhesive layer, and consequent lowering of adhesive strength and lowering of wet diffusivity, one or more pentafunctional or more active hydrogen group-containing monomers with respect to the total amount of one or more radically polymerizable monomers (M) ( MHF) is preferably 20 to 100% by mass, more preferably 40 to 100% by mass, still more preferably 60 to 100% by mass, particularly preferably 70 to 100% by mass, most preferably 80 It is mass - 100 mass %.

(gas generating agent (G))

A gas generating agent (G) is a compound which generate|occur|produces gas by irradiation of active energy rays, such as an ultraviolet-ray and an electron beam.

When an adherend to which the pressure-sensitive adhesive sheet is attached is irradiated with an active energy ray, gas is generated from the gas generating agent (G) included in the pressure-sensitive adhesive layer, and the generated gas can be collected between the adherend and the pressure-sensitive adhesive layer. A sufficient amount of gas collected between the adherend and the adhesive layer can act so that the adhesive layer is naturally peeled from the adherend.

In the adhesive sheet of this invention, a radically polymerizable monomer (M) superposes|polymerizes by irradiation of an active energy ray, and while the adhesive force and wet diffusivity of an adhesive layer fall, gas is generate|occur|produced in an adhesive layer. These actions match each other, so that the pressure-sensitive adhesive sheet can be easily peeled off from the adherend after irradiation with active energy rays. For example, the pressure-sensitive adhesive sheet can be easily peeled from the adherend by air blow or the like, and it is also possible to naturally peel the pressure-sensitive adhesive sheet from the adherend.

As gas generating agent (G), the nitrogen element containing compound which contains an N=N bond and produces|generates nitrogen gas by irradiation of an active energy ray is preferable. As the gas generating agent (G), at least one selected from the group consisting of an azo compound, an azide compound, a tetrazole compound, a tetrazole compound salt, and a bistetrazole compound is preferable. Among them, an azo compound is particularly preferable from the viewpoint of chemical stability of the compound and easiness of gas generation control.

_{The volume of N 2} generated per 1 g theoretically calculated from the chemical structural formula of the gas generating agent (G) is preferably 30 to 400 mL/g, more preferably 40 to 200 mL/g, particularly preferably 50 to 120 mL/g to be.

When the N ₂ generation volume per 1 g is 30 mL/g or more, when the active energy ray is irradiated to the adhesive layer, a sufficient amount of gas can be stably generated. If the _{volume of N 2} generated per 1 g is 400 mL/g or less, it is possible to stably suppress the start and progress of the reaction easily by irradiation of a small amount of ultraviolet light contained in the light of a fluorescent lamp and environmental light such as sunlight.

_{The N 2} generation volume per 1 g can be calculated|required from the following formula.

_{[N 2} generation volume per 1 g] (mL/g) = 22.4 × 1000 × [the number of N = N groups contained in one molecule] / [molecular weight]

Examples of the gas generating agent (G), shows the N = N group of theory N ₂ generated volume number / 1g each of which is contained in each compound having a molecular weight / the molecule are shown in Table 1.

In the table, gas generating agents (G11) to (G19) are examples of azo compounds.

In the table, gas generating agents (G21) to (G22) are examples of tetrazole compounds.

[Table 1]

The nitrogen element-containing compounds exemplified in Table 1 include compounds known as so-called radical polymerization initiators that generate radicals by heat and become a starting point of polymerization. The usage-amount in the case of adding as a radical polymerization initiator is less than 1 mass part normally with respect to a total of 100 mass parts of 1 or more types of monomers which are polymerization objects. Content of the gas generator (G) in an adhesion layer is more than the addition amount of a radical polymerization initiator, Preferably it is 2 mass % or more, More preferably, it is 3-30 mass %, Especially preferably, it is 5-20 mass %.

When the content of the gas generating agent (G) in the pressure-sensitive adhesive layer is 2% by mass or more, the amount of gas generated by irradiation with active energy rays becomes a sufficient amount, and the pressure-sensitive adhesive sheet can be easily peeled off from the adherend after irradiation with active energy rays. have.

When the content of the gas generating agent (G) is 30% by mass or less, it has sufficient transparency as a surface protection sheet for a panel display such as an LCD and a touch panel display, and a substrate and an optical member manufactured or used in the manufacturing process thereof, and It is easy to obtain the adhesive sheet which has a favorable UV transmittance|permeability. Preferred UV transmittance will be described later.

In addition, when a compound known as a radical polymerization initiator is used as the gas generating agent (G), a part thereof acts as a radical polymerization initiator while also acting as the gas generating agent (G).

(Radical polymerization initiator (RI))

The pressure-sensitive adhesive may contain a radical polymerization initiator (RI) that initiates polymerization of the radically polymerizable monomer (M) when irradiated with active energy rays, if necessary. When the radically polymerizable monomer (M) is ultraviolet curable, the pressure-sensitive adhesive preferably contains a radical polymerization initiator (RI) (the radical polymerization initiator (RI) in this case is also referred to as a photopolymerization initiator).

It does not restrict|limit especially as a radical polymerization initiator (RI), A well-known thing can be used. For example, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one , 1-Hydroxycyclohexylphenylketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and 2-methyl-1-[4-(methylthio)phenyl Acetophenone-type polymerization initiators, such as ]-2-morpholino propan-1-one; benzoin polymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzyl dimethyl ketal; Benzophenone-based polymerization initiators such as benzophenone, benzoylbenzoic acid, methylbenzoylbenzoate, 4-methylbenzophenone, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, and 4-benzoyl-4'-methyldiphenylsulfide ; Thioxanthone, 2-scroll thioxanthone, 2-methyl thioxanthone, isopropyl thioxanthone, and 2,4-diisopropyl thioxanthone tea tongye polymerization initiator such as thioxanthone; 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis( Trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, 2-piperonyl-4,6-bis(trichloromethyl) -s-triazine, 2,4-bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphtho-1-yl)-4,6-bis(trichloromethyl)-s -triazine, 2-(4-methoxy-naphtho-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl-(piperonyl)- triazine-based polymerization initiators such as 6-triazine and 2,4-trichloromethyl(4'-methoxystyryl)-6-triazine; acylphosphine oxide-based polymerization initiator; borate-based polymerization initiator; a carbazole-based polymerization initiator; An imidazole-type polymerization initiator etc. are mentioned. These can be used 1 type or 2 or more types.

Some of the exemplified radical polymerization initiators (RI) may also act as gas generators (G).

The compounding quantity in particular of the radical polymerization initiator (RI) in an adhesion layer is not restrict|limited, For example, it is about 0.5-1.5 mass %.

(sensitizer (RS))

The pressure-sensitive adhesive may also include one or more sensitizers (RS) as needed. The sensitizer (RS) absorbs active energy rays, such as ultraviolet rays and electron beams, and can accelerate the polymerization reaction by donating the energy obtained through this to another material.

As a sensitizer (RS), a well-known thing can be used, For example, Dye type compounds, such as a xanthene pigment, a coumarin pigment, a 3-ketocoumarin type compound, and a pyrometene pigment|dye; dialkyl aminobenzene compounds such as 4-dimethylamino ethyl benzoate and 4-dimethylamino benzoate 2-ethylhexyl; Mercaptan-type hydrogen donors, such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, and 2-mercaptobenzoimidazole, etc. are mentioned. These can be used 1 type or 2 or more types.

When the adhesive layer includes a sensitizer (RS), it is possible to effectively reduce the UV transmittance of the adhesive layer by increasing the reactivity of radical polymerization by irradiation with active energy rays. However, if the amount added is excessive, the reactivity of the adhesive layer is too high, and the reaction is easily initiated and proceeded by irradiation with a small amount of ultraviolet light included in ambient light such as fluorescent light and sunlight, and there is a risk of lowering the adhesive strength of the adhesive layer. have. When using a sensitizer (RS), it is preferable to use it in a small amount in the range in which radical polymerization does not advance before active energy ray irradiation.

(Plasticizer (P))

From the viewpoint of lowering the adhesive force of the pressure-sensitive adhesive layer and improving the wettability, the pressure-sensitive adhesive may also contain one or more plasticizers (P) as needed. The "plasticizer" here is a well-known plasticizer generally added in order to improve the wet diffusivity in an adhesive, and is a material which does not have active energy ray sclerosis|hardenability. It does not restrict|limit especially as a plasticizer (P), From a viewpoint of compatibility with other components, etc., organic acid ester is preferable.

Examples of esters of monobasic acid or polybasic acid with alcohol include isostearyl laurate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isostearyl palmitate, and stearic acid. Isocetyl, octyldodecyl oleate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, diisodecyl adipate, diisostearyl adipate, dibutyl sebacate, diisoce tyl, tributyl acetyl citrate, tributyl trimellitate, trioctyl trimellitate, trihexyl trimellitate, trioleyl trimellitate, and triisocetyl trimellitate etc. are mentioned.

As esters of other acids and alcohols, for example, unsaturated fatty acids or branched acids such as myristoleic acid, oleic acid, linoleic acid, linolenic acid, isopalmitic acid, and isostearic acid, ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol , and esters with alcohols such as sorbitan.

Examples of the ester of monobasic acid or polybasic acid and polyalkylene glycol include polyethylene glycol dihexylate, polyethylene glycol di-2-ethylhexylate, polyethylene glycol dilauryl acid, polyethylene glycol dioleate, and dipolyethylene adipate. Glycol methyl ether etc. are mentioned.

The molecular weight (formula or Mn) of organic acid ester from a viewpoint of wet diffusibility improvement etc. becomes like this. Preferably it is 250-1,000, More preferably, it is 400-900, Especially preferably, it is 500-850. When molecular weight is 250 or more, the heat resistance of an adhesion layer becomes favorable, and when molecular weight is 1,000 or less, wet-diffusion property of an adhesive becomes favorable.

The pressure-sensitive adhesive may not include a plasticizer (P). In this invention, even if it does not add a plasticizer (P) to an adhesive, 1 or more types of radically polymerizable monomer (M) may act as a plasticizer.

(solvent)

The pressure-sensitive adhesive may contain one or more solvents as needed. A well-known thing can be used as a solvent, Methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, etc. are mentioned. Ethyl acetate, toluene, etc. are particularly preferable from the viewpoints of the solubility of the hydroxyl-terminated urethane prepolymer (UPH) and the boiling point of the solvent.

(discoloration inhibitor)

The pressure-sensitive adhesive may include one or more types of deterioration preventing agents, if necessary. Thereby, the fall of the various characteristics by long-term use of an adhesive layer can be suppressed. Examples of the quality inhibitor include a hydrolysis-resistant agent, an antioxidant, an ultraviolet absorber, and a light stabilizer.

<Hydrolysis resistant agent>

When a carboxyl group is generated due to a hydrolysis reaction occurring in the adhesive layer under a (wet) thermal environment or the like, a hydrolysis resistant agent can be used to block the carboxyl group. Examples of the hydrolysis-resistant agent include carbodiimide-based, oxazoline-based, and epoxy-based agents. In particular, the carbodiimide type is preferable from the viewpoint of the hydrolysis inhibitory effect.

A carbodiimide-type hydrolysis inhibitor is a compound which has one or more carbodiimide groups.

Examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, diphenylcarbodiimide, and Naphthyl carbodiimide etc. are mentioned.

The polycarbodiimide compound can be produced by subjecting diisocyanate to a decarboxylation condensation reaction in the presence of a carbodiimidization catalyst. At this time, as diisocyanate, for example, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-diphenyl methane diisocyanate, 3,3'-dimethyl-4,4 '-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolyl Rendiisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tetramethylxylene diisocyanate, etc. are mentioned. Examples of the carbodiimidization catalyst include 1-phenyl-2-phosphorine-1-oxide, 3-methyl-2-phosphorine-1-oxide, 1-ethyl-3-methyl-2-phosphorine-1-oxide; Phosphorine oxides, such as 1-ethyl-2-phosphorine-1-oxide and these 3-phosphorine isomers, etc. are mentioned.

Examples of the oxazoline-based hydrolysis inhibitor include 2,2'-o-phenylenebis(2-oxazoline), 2,2'-m-phenylenebis(2-oxazoline), 2,2' -p-phenylenebis(2-oxazoline), 2,2'-p-phenylenebis(4-methyl-2-oxazoline), 2,2'-m-phenylenebis(4-methyl-2 -oxazoline), 2,2'-p-phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (4,4'-dimethyl-2-oxa) zoline), 2,2'-p-ethylenebis(2-oxazoline), 2,2'-tetramethylenebis(2-oxazoline), 2,2'-hexamethylenebis(2-oxazoline), 2 , 2'-octamethylenebis(2-oxazoline), 2,2'-ethylenebis(4-methyl-2-oxazoline), and 2,2'-diphenylenebis(2-oxazoline), etc. can be heard

As an epoxy-type hydrolyzing agent, For example, diglycidyl ether of aliphatic diols, such as 1, 6- hexanediol, neopentyl glycol, and polyalkylene glycol; polyglycidyl ethers of aliphatic polyols such as sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, and trimethylolpropane; polyglycidyl ethers of alicyclic polyols such as cyclohexanedimethanol; diglycidyl esters or polyglycidyl esters of aliphatic or aromatic polyhydric carboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, and sebacic acid; resorcinol, bis-(p-hydroxyphenyl)methane, 2,2-bis-(p-hydroxyphenyl)propane, tris-(p-hydroxyphenyl)methane, and 1,1,2,2- diglycidyl ether or polyglycidyl ether of polyhydric phenols such as tetrakis(p-hydroxyphenyl)ethane; N of amines such as N,N-diglycidylaniline, N,N-diglycidyltoluidine, and N,N,N',N'-tetraglycidyl-bis-(p-aminophenyl)methane -glycidyl derivatives; triglycidyl derivatives of aminophenols; triglycidyltris(2-hydroxyethyl)isocyanurate, and triglycidylisocyanurate; Epoxy resins, such as an orthocresol-type epoxy resin and a phenol novolak-type epoxy resin, etc. are mentioned.

The amount of the hydrolysis resistant agent added is not particularly limited, and is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the active hydrogen group-containing compound (HC) (preferably hydroxyl-terminated urethane prepolymer (UPH)). 0.2-4.5 mass parts, Especially preferably, it is 0.5-3 mass parts.

<Antioxidant>

As antioxidant, a radical scavenger, a peroxide decomposing agent, etc. are mentioned. As a radical scavenger, a phenol-type compound, an amine-type compound, etc. are mentioned. As a peroxide decomposing agent, a sulfur type compound, a phosphorus type compound, etc. are mentioned.

Examples of the phenolic compound include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearin-β-( 3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4 -Ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butyl) phenol), 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10- Tetraoxaspiro [5,5] undecane, benzenepropanoic acid, 3,5-bis (1,1-dimethylethyl) -4-hydroxy-, C7-C9 branched alkyl ester, 1,1,3-tris ( 2-Methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl) Benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydro Roxy-3'-t-butylphenyl)butyric acid]glycol ester, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2, 4,6-(1H,3H,5H)trione, and tocopherol; and the like.

Examples of the sulfur-based antioxidant include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearyl 3,3'-thiodipropionate. can

Examples of the phosphorus compound include triphenylphosphite, diphenylisodecylphosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenylditridecyl)phosphite, cyclic Neopentanetetraylbis(octadecylphosphite), tris(nonylphenyl)phosphite, tris(monononylphenyl)phosphite, tris(dinonylphenyl)phosphite, diisodecylpentaerythritol diphosphite, 9,10- Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-tert-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10 -phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, tris(2,4-di-tert-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,4-di-tert-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,6-di-tert-butyl-4-methylphenyl)phosphite, and 2, 2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite etc. are mentioned.

By using an antioxidant, thermal deterioration of a hydroxyl-terminated urethane prepolymer (UPH) can be prevented.

The amount of the antioxidant added is not particularly limited, and is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 100 parts by mass of the active hydrogen group-containing compound (HC) (preferably hydroxyl-terminated urethane prepolymer (UPH)). It is -3 mass parts, Especially preferably, it is 0.2-2 mass parts.

As the antioxidant, from the viewpoint of stability and antioxidant effect, it is preferable to use at least one phenolic compound as a radical scavenger, and at least one phenolic compound as a radical scavenger and at least one phosphorus compound as a peroxide decomposing agent. more preferably. Moreover, as antioxidant, it is especially preferable to use together the phenolic compound which is a radical scavenger, and the phosphorus compound which is a peroxide decomposing agent, and to use together these antioxidant and the hydrolysis-resistant agent mentioned above.

<Ultraviolet absorbent>

Examples of the ultraviolet absorber include a benzophenone-based compound, a benzotriazole-based compound, a salicylic acid-based compound, an oxalic acid anilide-based compound, a cyanoacrylate-based compound, and a triazine-based compound.

The addition amount of the ultraviolet absorber does not inhibit the initiation and progress of polymerization of the radically polymerizable monomer (M) by irradiation with active energy rays, and the radically polymerizable monomer (M) is easily exposed to ambient light such as fluorescent light and sunlight. ) can be appropriately designed within the range in which the reaction is not initiated. When the radically polymerizable monomer (M) is ultraviolet curable, the amount of the ultraviolet absorber to be added is designed according to the kind of the ultraviolet absorber, the wavelength range of ultraviolet rays irradiated to the adhesive layer, and the amount of accumulated light. The amount of the ultraviolet absorber added is preferably 0.01 to 3 parts by mass, more preferably 0.1 to 2.5 parts by mass relative to 100 parts by mass of the active hydrogen group-containing compound (HC) (preferably hydroxyl-terminated urethane prepolymer (UPH)). , Especially preferably, it is 0.2-2 mass parts.

<Light Stabilizer>

Examples of the light stabilizer include hindered amine compounds and hindered piperidine compounds. The amount of the light stabilizer to be added is not particularly limited, and is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 2 parts by mass, based on 100 parts by mass of the active hydrogen group-containing compound (HC) (preferably hydroxyl-terminated urethane prepolymer (UPH)). It is 0.1-1.5 mass part, Especially preferably, it is 0.2-1 mass part.

(Antistatic Agent (AS))

The pressure-sensitive adhesive may include one or more antistatic agents (AS) as needed. Examples of the antistatic agent (AS) include inorganic salts, ionic liquids, ionic solids, and surfactants, and particularly preferred are ionic liquids and ionic solids. In addition, "ionic liquid" is also called room temperature molten salt, and fluidity|liquidity is a salt at 25 degreeC.

Examples of the inorganic salt include sodium chloride, potassium chloride, lithium chloride, lithium perchlorate, ammonium chloride, potassium chlorate, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ammonium sulfate, potassium nitrate, sodium nitrate, sodium carbonate, and thiocy. Sodium phosphate etc. are mentioned.

Examples of the ionic liquid containing imidazolium ions include 1-ethyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide, 1,3-dimethylimidazoliumbis(trifluoro methylsulfonyl)imide, and 1-butyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide.

Examples of the ionic liquid containing pyridinium ions include 1-methylpyridiniumbis(trifluoromethylsulfonyl)imide, 1-butylpyridiniumbis(trifluoromethylsulfonyl)imide, 1- Hexylpyridiniumbis(trifluoromethylsulfonyl)imide, 1-octylpyridiniumbis(trifluoromethylsulfonyl)imide, 1-hexyl-4-methylpyridiniumbis(trifluoromethylsulfonyl) ) imide, 1-hexyl-4-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-octyl-4-methylpyridinium bis ( Fluorosulfonyl)imide, 1-methylpyridiniumbis(perfluoroethylsulfonyl)imide, and 1-methylpyridiniumbis(perfluorobutylsulfonyl)imide, etc. are mentioned.

Examples of the ionic liquid containing ammonium ions include 1-butyl-3-methylpyridiniumbis(trifluoromethanesulfonyl)imide, trimethylheptylammoniumbis(trifluoromethanesulfonyl)imide, N ,N-diethyl-N-methyl-N-propylammoniumbis(trifluoromethanesulfonyl)imide, N,N-diethyl-N-methyl-N-pentylammoniumbis(trifluoromethanesulfonyl) imide, N,N-diethyl-N-methyl-N-heptylammoniumbis(trifluoromethanesulfonyl)imide, and tri-n-butylmethylammoniumbistrifluoromethanesulfonimide; and the like. have.

In addition, commercially available ionic liquids, such as a pyrrolidinium salt, a phosphonium salt, and a sulfonium salt, can be used suitably.

An ionic solid is a salt of a cation and an anion like an ionic liquid, but is a substance which shows the property of a solid in 25 degreeC under normal pressure. As a cation, an alkali metal ion, a phosphonium ion, a pyridinium ion, an ammonium ion, etc. are preferable, for example.

Examples of the ionic solid containing alkali metal ions include lithium bis fluoro sulfonyl imide, lithium bis trifluoromethyl sulfonyl imide, lithium bis pentafluoroethyl sulfonyl imide, lithium bis heptafluoropropyl Sulfonylimide, lithium bis nonanefluorobutyl sulfonyl imide, sodium bis fluorosulfonyl imide, sodium bis trifluoromethyl sulfonyl imide, sodium bis pentafluoroethyl sulfonyl imide, sodium bis hepta Fluoropropylsulfonylimide, sodiumbisnonanefluorobutylsulfonylimide, potassiumbisfluorosulfonylimide, potassiumbistrifluoromethylsulfonylimide, potassiumbispentafluoroethylsulfonylimide, Potassium bis heptafluoropropyl sulfonyl imide, potassium bis nonanefluoro butyl sulfonyl imide, etc. are mentioned.

Examples of the ionic solid containing phosphonium ions include tetrabutyl phosphonium bis fluorosulfonyl imide, tetrabutyl phosphonium bis trifluoromethyl sulfonyl imide, tetrabutyl phosphonium bis pentafluoroethyl sulfonyl. Ponylimide, tetrabutyl phosphonium bis heptafluoropropyl sulfonyl imide, tetrabutyl phosphonium bis nonanefluoro butyl sulfonyl imide, tributyl hexadecyl phosphonium bis fluorosulfonyl imide, tributyl hexadecyl Phosphoniumbistrifluoromethylsulfonylimide, tributylhexadecylphosphoniumbispentafluoroethylsulfonylimide, tributylhexadecylphosphoniumbisheptafluoropropylsulfonylimide, tributylhexadecylphosphonium Bis nonanefluorobutyl sulfonyl imide, tetraoctyl phosphonium bis fluorosulfonyl imide, tetraoctyl phosphonium bis trifluoromethyl sulfonyl imide, tetraoctyl phosphonium bis pentafluoroethyl sulfonyl imide; Tetraoctyl phosphonium bis heptafluoropropyl sulfonyl imide, tetraoctyl phosphonium bis nonanefluoro butyl sulfonyl imide, etc. are mentioned.

Examples of the ionic solid containing pyridinium ions include 1-hexadecyl-4-methylpyridiniumbisfluorosulfonylimide and 1-hexadecyl-4-methylpyridiniumbistrifluoromethylsulfonyl. mide, 1-hexadecyl-4-methylpyridiniumbis pentafluoroethylsulfonylimide, 1-hexadecyl-4-methylpyridiniumbis heptafluoropropylsulfonylimide, and 1-hexadecyl-4- Methylpyridiniumbisnonanefluorobutylsulfonylimide etc. are mentioned.

Examples of the ionic solid containing ammonium ions include lauryl trimethylammonium chloride, tributylmethylbistrifluoromethylsulfonylimide, tributylmethylbispentafluoroethylsulfonylimide, and tributylmethylbishepta. Fluoropropylsulfonylimide, tributylmethylbis nonanefluorobutylsulfonylimide, octyltributylbistrifluoromethylsulfonylimide, octyltributylbispentafluoroethylsulfonylimide, jade Tyltributylbisheptafluoropropylsulfonylimide, octyltributylbisnonanefluorobutylsulfonylimide, tetrabutylbisfluorosulfonylimide, tetrabutylbistrifluoromethylsulfonylimide, tetra Butylbispentafluoroethylsulfonylimide, tetrabutylbisheptafluoropropylsulfonylimide, tetrabutylbisnonanefluorobutylsulfonylimide, etc. are mentioned.

In addition, a well-known ionic solid whose cation is a pyrrolidinium ion, an imidazolium ion, a sulfonium salt, etc. can be used suitably.

Examples of the surfactant include nonionic surfactants and anionic surfactants, and both types are classified into low-molecular surfactants and high-molecular surfactants.

Examples of the nonionic low molecular weight surfactant include glycerin fatty acid ester, polyoxyalkylenealkylether, polyoxyethylenealkylphenylether, polyoxyethylenealkylamine, polyoxyethylenealkylamine fatty acid ester, and fatty acid diethanolamide. .

Examples of the anionic low-molecular surfactant include alkyl sulfonates, alkylbenzene sulfonates, and alkyl phosphates.

Examples of the amphoteric low molecular surfactant include alkylbetaine and alkylimidazoliumbetaine.

Examples of the nonionic polymer surfactant include a polyether ester amide type, an ethylene oxide-epichlorohydrin type, and a polyether ester type.

Polystyrene sulfonic acid type|mold etc. are mentioned as anionic polymer surfactant.

Examples of the amphoteric polymeric surfactant include amino acid-type amphoteric surfactants such as higher alkylaminopropionate, betaine-type amphoteric surfactants such as higher alkyldimethylbetaine and higher alkyldihydroxyethylbetaine.

To [ the addition amount of antistatic agent (AS) / 100 mass parts of active hydrogen group containing compound (HC)), Preferably it is 0.01-10 mass parts, More preferably, it is 0.03-5 mass parts.

(leveling agent)

The pressure-sensitive adhesive may include a leveling agent as needed. By adding a leveling agent, the leveling property of an adhesive layer can be improved. As a leveling agent, an acryl-type leveling agent etc. are preferable from a viewpoint of suppressing the to-be-adhered body stain|pollution|contamination after peeling back adhesive sheet, which includes an acryl-type leveling agent, a fluorine-type leveling agent, and a silicone-type leveling agent.

The amount of the leveling agent added is not particularly limited, and from the viewpoint of suppressing contamination of the adherend after peeling the adhesive sheet and improving the leveling property of the adhesive layer, an active hydrogen group-containing compound (HC) (preferably a hydroxyl group-terminated urethane prepolymer (UPH)) With respect to 100 mass parts, Preferably it is 0.001-2 mass parts, More preferably, it is 0.01-1.5 mass parts, Especially preferably, it is 0.1-1 mass part.

(Other optional ingredients)

An adhesive can contain other arbitrary components as needed in the range which does not impair the effect of this invention. Examples of other optional components include catalysts, resins other than urethane-based resins, fillers (talc, calcium carbonate, titanium oxide, etc.), metal powder, colorants (pigments, etc.), thin materials, softeners, conductive agents, A silane coupling agent, a lubricant, a corrosion inhibitor, a heat-resistant stabilizer, a weather-resistant stabilizer, a polymerization inhibitor, an antifoaming agent, etc. are mentioned.

When the pressure-sensitive adhesive contains a catalyst, it is preferable to add a known catalytic action inhibitor such as acetylacetone for the purpose of improving the pot life of the pressure-sensitive adhesive.

(mixture ratio)

The adhesive is

At least one non-radically polymerizable active hydrogen group-containing compound (HC) having a plurality of active hydrogen groups and not having a (meth)acryloyl group;

At least one radical polymerizable monomer (M) comprising at least one radical polymerizable active hydrogen group-containing monomer (MH) having at least one active hydrogen group and at least two (meth)acryloyl groups;

A polyfunctional isocyanate compound (I), and

A gas generating agent (G) is included.

Although these mixing ratios in particular are not restrict|limited, Preferable mixing ratios are as follows.

The amount of the at least one polyfunctional isocyanate compound (I) with respect to 100 parts by mass of the at least one active hydrogen group-containing compound (HC) (preferably at least one hydroxyl-terminated urethane prepolymer (UPH)) is preferably 1 to 40 It is a mass part, More preferably, it is 3-40 mass parts, Especially preferably, it is 5-35 mass parts. As for the quantity of 1 or more types of polyfunctional isocyanate compound (I), if it is 1 mass part or more, the cohesive force of an adhesion layer will become favorable, and if it is 40 mass parts or less, a pot life will become favorable.

The amount of at least one radically polymerizable active hydrogen group-containing monomer (MH) with respect to 100 parts by mass of at least one active hydrogen group-containing compound (HC) (preferably at least one hydroxyl group-terminated urethane prepolymer (UPH)) is the active energy From a viewpoint of the adhesive force before irradiation with a line|wire, Preferably it is 2-150 mass parts, More preferably, it is 2-95 mass parts, Especially preferably, it is 2-50 mass parts, Most preferably, it is 2-35 mass parts.

The amount of at least one radically polymerizable active hydrogen group-containing monomer (MH) with respect to 100 parts by mass of at least one active hydrogen group-containing compound (HC) (preferably at least one hydroxyl group-terminated urethane prepolymer (UPH)) is the active energy From the viewpoint of the effect of reducing the wet diffusivity by radiation, preferably 2-150 parts by mass, more preferably 10-140 parts by mass, particularly preferably 30-130 parts by mass, and most preferably 50-120 parts by mass. is wealth

In view of the balance of the above two required performances, at least one radical polymerizable activity with respect to 100 parts by mass of at least one active hydrogen group-containing compound (HC) (preferably at least one hydroxyl group-terminated urethane prepolymer (UPH)) The amount of the hydrogen group-containing monomer (MH) is preferably 2 to 150 parts by mass, more preferably 10 to 95 parts by mass, and particularly preferably 30 to 50 parts by mass. However, when one of the above two required performance is more important, the amount of one or more radically polymerizable active hydrogen group-containing monomers (MH) may be designed according to the important performance.

As described above, the at least one radical polymerizable monomer (M) may include at least one other radical polymerizable monomer (MO) other than the active hydrogen group-containing monomer (MH) as needed. The amount of the at least one radically polymerizable monomer (M) with respect to 100 parts by mass of the at least one active hydrogen group-containing compound (HC) (preferably at least one hydroxyl-terminated urethane prepolymer (UPH)) is preferably 10 to 150 It is a mass part, More preferably, it is 30-100 mass parts.

From a viewpoint of the peelability improvement effect by active energy ray irradiation, content of the gas generating agent (G) in an adhesion layer becomes like this. Preferably it is 2 mass % or more, More preferably, it is 3-30 mass %, Especially preferably, 5 -20 mass %.

(Manufacturing method of adhesive)

The manufacturing method in particular of an adhesive is not restrict|limited.

Prepare at least one active hydrogen group-containing compound (HC), preferably at least one hydroxyl-terminated urethane prepolymer (UPH) synthesized by the above method. The hydroxyl-terminated urethane prepolymer (UPH) may be in the form of a solution containing a solvent.

With respect to the at least one active hydrogen group-containing compound (HC) (preferably at least one hydroxyl-terminated urethane prepolymer (UPH)), at least one radical having at least one active hydrogen group and at least two (meth)acryl groups At least one radically polymerizable monomer (M) including a polymerizable active hydrogen group-containing monomer (MH), a polyfunctional isocyanate compound (I), a gas generator (G), and optionally one or more other optional components An adhesive can be manufactured by adding and mixing.

[Adhesive sheet]

The adhesive sheet of this invention contains a base material sheet and the adhesive layer formed on the at least one surface of this base material sheet. The pressure-sensitive adhesive layer is made of a coated product of the pressure-sensitive adhesive, and has active energy ray curability. If necessary, the exposed surface of the pressure-sensitive adhesive layer may be covered with a release sheet. In addition, the release sheet is peeled off before sticking the pressure-sensitive adhesive sheet to the adherend.

1, the schematic sectional drawing of the adhesive sheet of 1st Embodiment which concerns on this invention is shown. In Fig. 1, reference numeral 10 denotes an adhesive sheet, reference numeral 11 denotes a base sheet, reference numeral 12 denotes an adhesive layer, and reference numeral 13 denotes a release sheet. The pressure-sensitive adhesive sheet 10 is a single-sided pressure-sensitive adhesive sheet in which an adhesive layer is formed on one surface of the base sheet.

2, the schematic cross section of the adhesive sheet of 2nd Embodiment which concerns on this invention is shown. In Fig. 2, reference numeral 20 denotes an adhesive sheet, reference numeral 21 denotes a base sheet, reference numerals 22A and 22B denote an adhesive layer, and reference numeral 23A and 23B denote a release sheet. The adhesive sheet 20 is a double-sided adhesive sheet in which adhesive layers were formed on both surfaces of a base material sheet.

It does not restrict|limit especially as a base material sheet, A resin sheet, paper, metal foil, etc. are mentioned. The base sheet may be a laminated sheet in which any one or more layers are laminated on at least one surface of the base sheet. A simple adhesion treatment such as corona discharge treatment and application of an anchor coating agent may be applied to the surface of the base sheet on which the pressure-sensitive adhesive layer is formed if necessary.

It does not restrict|limit especially as structural resin of a resin sheet, Ester-type resin, such as polyethylene terephthalate (PET); olefin resins such as polyethylene (PE) and polypropylene (PP); vinyl-based resins such as polyvinyl chloride; amide resins such as nylon 66; urethane-based resins (including foams); combinations thereof, and the like.

The thickness in particular of the resin sheet except a polyurethane sheet is not restrict|limited, Preferably it is 15-300 micrometers. The thickness of the polyurethane sheet (including foam) is not particularly limited, and is preferably 20 to 50,000 µm.

It does not restrict|limit especially as paper, Plain paper, coated paper, art paper, etc. are mentioned.

It does not restrict|limit especially as a structural metal of metal foil, Aluminum, copper, these combinations, etc. are mentioned.

It does not restrict|limit especially as a release sheet, A well-known release sheet in which the well-known peeling process, such as a release agent application|coating, was given to the surface of base material sheets, such as a resin sheet or paper, can be used.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and can be appropriately designed according to the use and the like. Uses, such as a surface protection sheet, Preferably it is 0.1-200 micrometers, More preferably, it is 30-200 micrometers, Especially preferably, it is 50-200 micrometers, Most preferably, it is 75-150 micrometers.

When the thickness of the adhesive layer is within the above range, it has sufficient transparency as a surface protection sheet for a panel display such as an LCD and a touch panel display, and a substrate and an optical member manufactured or used in the manufacturing process, and has good UV transmittance An adhesive sheet can be easily obtained.

[Method for producing adhesive sheet]

An adhesive sheet can be manufactured by a well-known method.

First, an adhesive is coated on the surface of a base material sheet, and the coating layer which consists of an adhesive is formed. A known method can be applied as a coating method, The roll coater method, the comma coater method, the die coater method, the reverse coater method, the silkscreen method, the gravure coater method, etc. are mentioned.

Next, the coating layer is heat-dried to form an adhesion layer. Heat drying temperature in particular is not restrict|limited, About 60-150 degreeC is preferable. The thickness of the pressure-sensitive adhesive layer (thickness after drying) can be appropriately designed according to the use within the range where suitable transparency and UV transmittance are obtained.

Next, a release sheet is affixed to the exposed surface of an adhesion layer by a well-known method as needed.

A single-sided adhesive sheet can be manufactured as mentioned above.

A double-sided adhesive sheet can be manufactured by performing the said operation on both surfaces.

Contrary to the above method, an adhesive may be applied to the surface of the release sheet to form a coating layer made of the adhesive, then the coating layer may be dried by heating to form an adhesive layer, and the base sheet may be laminated on the exposed surface of the adhesive layer.

The method for producing the pressure-sensitive adhesive sheet preferably includes a coating step of coating the pressure-sensitive adhesive on the base sheet, a heating step of heating and drying the formed coating layer to form a pressure-sensitive adhesive layer, and winding the obtained pressure-sensitive adhesive sheet around a roll core to form a pressure-sensitive adhesive sheet roll A winding process to make into and a curing process for curing the pressure-sensitive adhesive sheet roll are included.

Immediately after production of the pressure-sensitive adhesive, at least one non-radically polymerizable active hydrogen group-containing compound (HC) and at least one radical polymerizable active hydrogen group-containing monomer having at least one active hydrogen group and at least two (meth)acryloyl groups The reaction between (MH) and the polyfunctional isocyanate compound (I) proceeds. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet contains these reaction products.

(UV transmittance)

When a radically polymerizable monomer (M) is ultraviolet curable, it is preferable that the adhesive sheet of this invention has moderate ultraviolet transmittance.

In this specification, the transmittance|permeability in wavelength 365nm is defined as "UV transmittance|permeability". "UV transmittance" can be measured by the method described in the item of the later [Example].

Since the adhesive layer contained in the adhesive sheet of the present invention absorbs ultraviolet rays and converts the absorbed ultraviolet rays into energy to radically polymerize and foam, it is preferable that the UV transmittance is low. From this viewpoint, the UV transmittance of the pressure-sensitive adhesive sheet of the present invention is preferably 82% or less, more preferably 81% or less, particularly preferably 79% or less, and most preferably 75% or less.

When an ultraviolet-ray is irradiated from the base material sheet side with respect to the to-be-adhered body with an adhesive sheet, it is preferable that an ultraviolet-ray reaches to the contact interface of an adhesive layer and to-be-adhered body. From this viewpoint, the UV transmittance|permeability of the adhesive sheet of this invention becomes like this. Preferably it is 1 % or more, More preferably, it is 10 % or more, Especially preferably, it is 20 % or more.

The UV transmittance changes depending on the type (chemical structure) and amount of the gas generator (G), the type (chemical structure) and amount of the sensitizer (RS), and the thickness of the adhesive layer. It is preferable to adjust these conditions so that the UV transmittance may be 82% or less.

In the present invention, the UV transmittance can be effectively reduced because the adhesive layer contains a gas generating agent (G) that absorbs ultraviolet rays and, if necessary, a sensitizer (RS) that absorbs ultraviolet rays.

(Heize)

When the pressure-sensitive adhesive sheet of the present invention is used for applications such as panel displays and touch panel displays such as LCDs, and surface protection sheets for substrates and optical members produced or used in these manufacturing processes, it is preferable that transparency is high. A "haze value" is mentioned as a parameter|index of transparency.

The haze value in particular of the adhesive sheet of this invention is not restrict|limited, Preferably it is 3 or less, More preferably, it is 2 or less.

A haze value can be measured based on JIS-K7136, for example.

[How to use the adhesive sheet]

The use method of the 1st adhesive sheet of this invention is,

A step of sticking the pressure-sensitive adhesive sheet of the present invention to the surface of the adherend;

The process of irradiating active energy rays, such as an ultraviolet-ray and an electron beam, with respect to the adhesive sheet affixed on the surface of a to-be-adhered body, and reducing the adhesive force of an adhesive sheet is included.

The use method of the 2nd adhesive sheet of this invention is,

A step of adhering the pressure-sensitive adhesive sheet to the surface of the adherend;

With respect to the adhesive sheet of this invention stuck on the surface of a to-be-adhered body, an active energy ray is irradiated, the adhesive force of an adhesive sheet is reduced, and the self-weight of the adhesive layer with respect to the acrylic resin board measured by the later method after active energy ray irradiation. ) The adhesion time shall be 30 second or more, and the process of peeling the adhesive sheet in which adhesive force fell from a to-be-adhered body is included.

In the manufacturing process of panel displays such as liquid crystal displays (LCD) and organic electroluminescence displays (OELD), and touch panel displays, etc., in order to improve productivity, an adherend with an adhesive sheet is transported at high speed to a processing unit that performs a necessary process. it is preferable For example, the automatic high-speed conveyance which adsorb|sucks and lifts the to-be-adhered body with an adhesive sheet from the side of an adhesive sheet using a vacuum suction member, and conveys it to a desired position is examined. In this automatic high-speed conveyance, it is preferable that the to-be-adhered body with an adhesive sheet has sufficient adhesive force so that an adhesive sheet will not peel from a to-be-adhered body while being adsorb|sucked by the vacuum suction member. On the other hand, in the to-be-adhered body to which the adhesive sheet has completed the required process, it is preferable that the adhesive sheet has comparatively low adhesive force so that the adhesive sheet can be peeled at high speed. It is preferable that the adhesive sheet can be easily peeled from the to-be-adhered body with an adhesive sheet which completed the required process.

The adhesive layer contained in the adhesive sheet of this invention contains the radically polymerizable monomer (M) and the gas generator (G) which generate|occur|produces gas by irradiation of an active energy ray. In the adhesive sheet of this invention, a radically polymerizable monomer (M) superposes|polymerizes by irradiation of an active energy ray, and while the adhesive force and wet diffusivity of an adhesive layer fall, gas is generate|occur|produced in an adhesive layer. These actions are compatible with each other, so that the pressure-sensitive adhesive sheet can be easily peeled off from the adherend after irradiation with active energy rays. For example, the pressure-sensitive adhesive sheet can be easily peeled from the adherend by air blow or the like, and it is also possible to naturally peel the pressure-sensitive adhesive sheet from the adherend.

The adhesive force and wet diffusivity before and after irradiation of the active energy ray of an adhesion layer can be designed suitably according to a use and use conditions. It is preferable to design as follows in the use of high-speed conveyance of the to-be-adhered body with an adhesive sheet using the vacuum adsorption|suction member as described above.

The adhesive layer, before irradiation with active energy rays, using a tensile tester according to JIS Z0237, the adhesive force measured under the conditions of a peeling rate of 0.3 m/min and a peeling angle of 180° is 0.1 gf/25 mm or more, preferably 0.5 gf/25 mm or more, particularly preferably 1.0 gf/25 mm or more.

The adhesive layer, before irradiation with active energy rays, using a tensile tester in accordance with JIS Z0237, the adhesive force measured under the conditions of a peeling rate of 0.3 m/min and a peeling angle of 180° is 26 gf/25 mm or less, preferably 20 gf/ 25 mm or less, particularly preferably 10 gf/25 mm or less.

When the adhesive force of the adhesive layer is equal to or greater than the lower limit, the adherend to which the adhesive sheet is attached may have sufficient adhesive strength to prevent the adhesive sheet from peeling off the adherend while being adsorbed to the vacuum adsorption member.

When the adhesive force of the adhesive layer is equal to or greater than the lower limit, the adherend to which the adhesive sheet is attached may have sufficient adhesive strength to prevent the adhesive sheet from being easily peeled off the adherend by air blow.

Before active energy ray irradiation as the said adhesive force of an adhesion layer is below the said upper limit, it has favorable re-peelability and can stick again.

The reduction rate in particular of the adhesive force after irradiation with respect to the irradiation of the active energy ray of an adhesion layer before irradiation of an active energy ray is not restrict|limited, Preferably it is 2/3 or less, More preferably, it is 1/2 or less, Especially preferably, it is 1/3 or less.

"Wet diffusivity" can be evaluated according to the self-weight adhesion time with respect to an acrylic resin board, for example. In this specification, "self-weight adhesion time with respect to an acrylic resin board" shall be measured by the following method.

Hold both ends in the longitudinal direction of a 100 mm wide and 200 mm long adhesive sheet with both hands, and bend the adhesive sheet so that the adhesive layer faces outward, so that both ends of the adhesive sheet are aligned. In this state, the pressure-sensitive adhesive layer at the center of the pressure-sensitive adhesive sheet is brought into contact with the acrylic resin plate. In this state, release the hands holding both ends. After releasing both hands, the time until the entire adhesive layer adheres to the acrylic resin plate is measured as the self-weight attachment time. As an acrylic resin board, "Acrylite L" by a Mitsubishi Rayon company can be used, for example.

Before active energy ray irradiation, the shorter the self-weight adhesion time of the adhesive layer to the acrylic resin plate, the better the wet diffusivity (affinity to the adherend), which is preferable.

Before active energy ray irradiation, the self-weight adhesion time to the acrylic resin board of an adhesion layer becomes like this. Preferably it is 15 second or less, More preferably, it is 10 second or less, Especially preferably, it is 8 second or less.

If the self-weight adhesion time of the adhesive layer to the acrylic resin plate is 15 seconds or less, before active energy ray irradiation, the adhesive layer has sufficient wettability to the adherend, and the adhesive sheet without air bubbles is applied to the adherend. It can be attached cleanly.

In general, the acrylic adhesive layer has poor wet diffusion properties, and the self-weight adhesion time to the acrylic resin plate is more than 15 seconds.

Generally, since a urethane-type adhesive layer is excellent in wet diffusion property, before active energy ray irradiation, the self-weight adhesion time with respect to an acrylic resin board is 15 second or less. To improve the wettability of the urethane-based pressure-sensitive adhesive layer. If necessary, a radically polymerizable monomer (M) having an alkyleneoxy group such as a plasticizer (P), an ethyleneoxy (EO) group and a propyleneoxy (PO) group, or a radically polymerizable monomer (M) having an alkyl chain, etc. Available.

In this invention, the wet-diffusion property of an adhesion layer can be effectively reduced by irradiation of an active energy ray. After active energy ray irradiation, it is preferable that the self-weight adhesion time with respect to the acrylic resin board of an adhesion layer is 30 second or more. If the self-weight adhesion time to the acrylic resin plate of the adhesive layer is 30 seconds or more, reattachment of the part naturally peeled by gas generation can be effectively suppressed.

As described above, according to the present invention, before irradiation with active energy rays, it has good wettability to the adherend, has re-peelability that can be re-attached to the adherend, and has an adhesive force that is not easily peeled off to the adherend. It is possible to provide a urethane-based pressure-sensitive adhesive sheet that can be pasted and can be easily peeled off from an adherend after irradiation with an active energy ray.

After irradiation with an active energy ray, the pressure-sensitive adhesive sheet can be easily peeled off from the adherend by, for example, air blow or the like, and the pressure-sensitive adhesive sheet can be naturally peeled from the adherend.

[Usage]

The adhesive sheet of this invention can be used with forms, such as a tape, a label, a seal|sticker, and a double-sided tape. The pressure-sensitive adhesive sheet of the present invention is suitably used as a surface protection sheet, a cosmetic sheet, an anti-slip sheet, and the like.

In addition, unless otherwise specified in this specification, "sheet" shall include "film" and "tape".

Panel displays such as liquid crystal displays (LCDs) and organic electroluminescence displays (OELDs), and touch panel displays in which such panel displays and touch panels are combined, include TVs, personal computers (PCs), mobile phones, portable information terminals, and the like. It is widely used in electronic devices of

The pressure-sensitive adhesive sheet of the present invention is a panel display and touch panel display such as LCD, and a substrate (a glass substrate, and an ITO (indium tin oxide) film formed on the glass substrate, etc. ) and as a surface protection sheet for optical members and the like.

[Example]

Hereinafter, synthesis examples, examples according to the present invention, and comparative examples will be described. In addition, in the following description, unless otherwise specified, "part" means a mass part, "%" means mass %, and "RH" shall mean a relative humidity. Unless otherwise specified, the unit of the compounding quantity in a table|surface is "mass part". Unless otherwise specified, the compounding quantity of components other than a solvent is a non-volatile matter conversion value.

[Measurement of molecular weight]

The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by the gel permeation chromatography (GPC) method. The measurement conditions are as follows. In addition, both Mw and Mn are polystyrene conversion values.

Device: SHIMADZU Prominence (manufactured by Shimadzu Corporation),

Column: 3 SHODEX LF-804 (manufactured by Showa Denko Co., Ltd.) connected in series,

Detector: differential refractive index detector,

Solvent: tetrahydrofuran (THF);

flow rate: 1 mL/min;

solvent temperature: 40℃,

sample concentration: 0.2%;

Sample injection volume: 200 μL.

[material]

The materials used were as follows.

<Active hydrogen group-containing compound (HX)>

(HX-1): Kurare polyol P-2010, polyester polyol, number average molecular weight Mn2000, number of hydroxyl groups 2, Kuraray Corporation,

(HX-2): Sannix GP-3000, polyether polyol, number average molecular weight Mn3000, number of hydroxyl groups 3, manufactured by Sanyo Kasei Co., Ltd.,

(HX-3): Sannix GL-3000, polyether polyol, number average molecular weight Mn3000, number of hydroxyl groups 3, manufactured by Sanyo Kasei Co., Ltd.

<Polyisocyanate (N)>

(N-1): desmodul H, hexamethylene diisocyanate (HDI), manufactured by Sumika Covestro Urethane,

(N-2): Desmodule T-80, tolylene diisocyanate (TDI), manufactured by Sumika Covestro Urethane.

<Polyfunctional isocyanate compound (I)>

(I-1): Sumijul N3300, a nurate form of hexamethylene diisocyanate, 100% nonvolatile matter, manufactured by Sumika Covestro Urethane,

(I-2): Takenate D-110N, a trimethylolpropane a duct body of xylene diisocyanate, nonvolatile matter 75%, Mitsui Chemicals Co., Ltd. product.

<Radically polymerizable monomer (M) containing active hydrogen group (radically polymerizable active hydrogen group-containing monomer (MH))>

(MH-1): MIRAMER M500, dipentaerythritol pentaacrylate, 5 acryloyl groups, 1 hydroxyl group, manufactured by MIWON,

(MH-2): MIRAMER M340, pentaerythritol triacrylate, 3 acryloyl groups, 1 hydroxyl group, manufactured by MIWON.

<Radically polymerizable monomer (M) not containing an active hydrogen group>

(MO-3): MIRAMER M600, dipentaerythritol hexaacrylate, 6 acryloyl groups, 0 hydroxyl groups, manufactured by MIWON,

(MO-4): MIRAMER M220, tripropylene glycol diacrylate, 2 acryloyl groups, 0 hydroxyl groups, manufactured by MIWON,

(MO-5): MIRAMER M202, 1,6-hexanediolethoxylate diacrylate, 2 acryloyl groups, 0 hydroxyl groups, manufactured by MIWON.

<Photoinitiator (RI)>

(RI-1): Irgacure TPO, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, manufactured by BASF,

(RI-2): SB-PI 712, 4-methylbenzophenone, manufactured by Sanyo Bo Eki Corporation.

<Gas generating agent (G)>

As the gas generating agent (G), (G-18) and (G-14) described in Table 1 were prepared.

<sensitizer (RS)>

(RS-1): UVS-1331, a compound represented by the following structural formula, manufactured by Kawasaki Chemical Co., Ltd.

[Formula 1]

<Plasticizer (P)>

(P-1): Acetyl tributyl citrate (ATBC), manufactured by Mitsubishi Chemical.

<Antioxidant (O)>

(O-1): Irganox 1010, a hindered phenolic antioxidant, manufactured by BASF.

<Antistatic agent (AS)>

(AS-1): IL-P14, ionic liquid, manufactured by Koei Chemical Co., Ltd.

[Synthesis example of a solution of hydroxyl-terminated urethane prepolymer (UPH)]

(Synthesis Example 1)

400 parts of active hydrogen group-containing compound (HX-1), 600 parts of active hydrogen group-containing compound (HX-2) in a four-necked flask equipped with a stirrer, reflux cooling tube, nitrogen introduction tube, thermometer, and dropping funnel , and 57 parts of polyisocyanate (N-1). 705 parts of toluene, 0.1 part of dibutyltin dilaurate as a catalyst, and 0.04 2-ethyl tin hexanoate were added and mixed here. The temperature of the internal solution was gradually raised to 90°C, and reaction was performed at 90°C for 2 hours.

After frequent sampling was performed and the disappearance of the remaining isocyanate groups was confirmed by an infrared absorption (IR) spectrum, the reaction solution was cooled to 30° C. to complete the reaction.

As described above, a solution (non-volatile content: 60%) of a hydroxyl group-terminated urethane prepolymer (UPH1) having a hydroxyl group of 17.1 mgKOH/g was obtained. The obtained hydroxyl-terminated urethane prepolymer (UPH1) had a weight average molecular weight Mw of 83,000. Table 2 shows the compounding composition and Mw and hydroxyl value of the obtained hydroxyl-terminated urethane prepolymer.

(Synthesis Examples 2 to 5)

In Synthesis Examples 2 to 5, a colorless and transparent hydroxyl-terminated urethane prepolymer ( Solutions of UPH-2) to (UPH-5) were obtained. In each synthesis example, the compounding composition and Mw and hydroxyl value of the obtained hydroxyl-terminated urethane prepolymer are shown in Table 2.

[Table 2]

[Synthesis example of acrylic resin (AR)]

(Synthesis Example 21)

990 parts of n-butyl acrylate, 10 parts of 4-hydroxybutyl acrylate, and 1000 parts of ethyl acetate were prepared and mixed in a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel. The internal solution was heated up gradually to 90 degreeC, and after confirming solvent reflux, 2 parts of azobisisobutyronitrile was added and mixed. After 8 hours, the reaction solution was cooled to complete the reaction. As mentioned above, the solution (non-volatile matter: 50%) of an acrylic resin (AR-1) was obtained. The weight average molecular weight Mw of the obtained acrylic resin was 890,000.

[Preparation of adhesive and adhesive sheet]

(Example 1)

To the solution containing 100 parts of hydroxyl-terminated urethane prepolymer (UPH1) obtained in Synthesis Example 1, 5 parts of a polyfunctional isocyanate compound (I-1) and 25 parts of a radically polymerizable monomer (MH-1) containing an active hydrogen group parts, 10 parts of a radically polymerizable monomer (MO-4) not containing an active hydrogen group, 1 part of a photoinitiator (RL-1), 1 part of a photoinitiator (RL-2), 1 part of a gas generator (G-1) ) 20 parts, antioxidant (O-1) 0.1 part, antistatic agent (AS-1) 0.1 part mix|blended, and 80 part ethyl acetate was mix|blended as a solvent, and a urethane adhesive was obtained by stirring with a disper. In addition, the compounding quantity of each material other than a solvent is represented by the quantity of a non-volatile matter (it is the same also in another Example and a comparative example).

As the base sheet, a 75 µm thick polyethylene terephthalate sheet (double-sided simple adhesive PET sheet, Cosmoshine A-4300, manufactured by Toyobo Corporation) was prepared. The obtained adhesive was coated on one side of this base material sheet, and it heat-dried at 100 degreeC for 5 minutes, and the 75-micrometer-thick adhesive layer was formed. On this adhesive layer, a 38-micrometer-thick peeling sheet (Supertech SP-PET38, Lintec company make) was pasted, and the adhesive sheet was obtained. After curing for 1 week in an atmosphere of 23°C-50%RH, various evaluations were received.

The compounding composition of the adhesive, the thickness of the adhesive layer, and the evaluation results are shown in Tables 3 and 7. In addition, in each example of Table 3 - Table 6, conditions not described in a table|surface were made into common conditions.

(Examples 2 to 27, Comparative Examples 1 to 6)

In Examples 2 to 27 and Comparative Examples 1 to 6, in the same manner as in Example 1, except that the compounding composition of the pressure-sensitive adhesive and the thickness of the pressure-sensitive adhesive layer were changed as shown in Tables 3 to 6, urethane-based or An acrylic pressure-sensitive adhesive sheet was prepared. The evaluation results are shown in Tables 7 to 10.

(Example 28)

A urethane-based adhesive sheet was prepared in the same manner as in Example 1, except that the following materials were mixed and stirred with a disper to obtain a urethane-based adhesive by a one-shot method.

Active hydrogen group-containing compound (HX-1): 40 parts;

Active hydrogen group-containing compound (HX-2): 60 parts;

polyfunctional isocyanate compound (I-1): 15 parts;

dibutyltin dilaurate (catalyst): 0.1 part;

2- Tin ethylhexanoate (catalyst): 0.04 parts,

radically polymerizable monomer (MH-1): 25 parts;

radically polymerizable monomer (MO-4): 10 parts;

Photoinitiator (RI-1): 1 part;

Photoinitiator (RI-2): 1 part;

Gas generating agent (G-18): 20 parts;

Antioxidant (O-1): 0.1 part;

Antistatic agent (AS-1): 0.1 part;

Ethyl acetate (solvent): 80 parts.

The compounding composition of the adhesive, the thickness of the adhesive layer, and the evaluation results are shown in Tables 5 and 9.

[Evaluation items and evaluation method]

The evaluation item and evaluation method of an adhesive sheet are as follows.

(Adhesiveness and re-peelability before ultraviolet (UV) irradiation)

A test piece having a size of 25 mm in width and 100 mm in length was cut out from the obtained adhesive sheet and left to stand for 30 minutes in an atmosphere of 23°C -50%RH. Next, the release sheet was peeled off from the test piece under the same atmosphere, the exposed adhesive layer side of the test piece was attached to a stainless (SUS) plate, pressed using a 2 kg roll, and left to stand for 24 hours. Adhesive force (adhesive force before UV irradiation) with a peeling speed of 0.3 m/min and a peeling angle of 180° using a tensile tester (Tensiron: manufactured by Orientec Co., Ltd.) in accordance with JIS Z0237 for the obtained adherend with an adhesive sheet. was measured. The one with low adhesive force has high re-peelability and is easy to reattach. The evaluation criteria are as follows.

(double-circle): 10gf/25mm or less, excellent.

○: Exceeding 10 gf/25 mm and less than or equal to 20 gf/25 mm, good.

△: more than 20 gf/25 mm and less than or equal to 26 gf/25 mm, possible.

×: Exceeding 26 gf/25 mm, impractical.

(Difficult to peel off due to air blow before ultraviolet (UV) irradiation)

A test piece having a size of 100 mm in width and 100 mm in length was cut out from the obtained adhesive sheet and left to stand for 30 minutes in an atmosphere of 23°C -50%RH. Next, peel the release sheet from the test piece under the same atmosphere, attach the exposed adhesive layer side of the test piece to an acrylic resin plate larger than the test piece ("Acrylite L" manufactured by Mitsubishi Rayon, 110 mm wide, 110 mm long) and left for 24 hours did It was attached so that the center of the test piece and the center of the acrylic resin plate were almost coincident.

With respect to the obtained adherend to which the adhesive sheet is attached, at a position 10 mm from one end of the adhesive sheet in the horizontal direction, using an air gun with a nozzle diameter of 2.0 mmφ, air is blown under the condition of a compressor pump pressure of 0.3 MPa for 10 seconds. It was sprayed and it was confirmed whether an adhesive sheet peeled.

The said test was done about 20 test pieces, and the number (peel number) of the test pieces which peeled was investigated. When the pressure-sensitive adhesive sheet failed to peel (that is, the number of peels is 0) for all the test pieces, the pressure-sensitive adhesive sheet is difficult to peel from the adherend to which the pressure-sensitive adhesive sheet is attached during manufacturing processes such as LCD and touch panel displays, which is good.

(double-circle): The number of peeling is 0, excellent.

x: The number of peelings is 1-20, impractical.

(Self-weight adhesion before ultraviolet (UV) irradiation (easy to spread wetness))

A test piece having a size of 100 mm in width and 200 mm in length was cut out from the obtained adhesive sheet and left to stand for 30 minutes in an atmosphere of 23°C -50%RH. Then, in the same atmosphere, the release sheet was peeled from the test piece, and self-weight adhesiveness was evaluated as follows.

Both ends of the adhesive sheet in the longitudinal direction were held with both hands, the adhesive sheet was curved so that the adhesive layer faced outward, and the both ends of the adhesive sheet were aligned. In this state, the pressure-sensitive adhesive layer at the center of the pressure-sensitive adhesive sheet was brought into contact with an acrylic resin plate ("Acrylite L" manufactured by Mitsubishi Rayon Co., Ltd.). In this state, the hands holding both ends were released. The time until the whole adhesion layer closely_contact|adhered to an acrylic resin board by its own weight after removing a hand was measured as self-weight adhesion time, and the wet-diffusion property of an adhesive was evaluated.

The shorter the self-weight adhesion time, the better the wet diffusibility (affinity to the adherend). The evaluation criteria are as follows.

(double-circle): Self-weight attachment time 8 second or less, excellent.

(circle): Self-weight attachment time exceeds 8 second and 10 second or less, good.

(triangle|delta): Self-weight attachment time is more than 10 seconds and 15 seconds or less, possible.

x: Self-weight attachment time exceeds 15 seconds, and is not practical.

(ultraviolet (UV) transmittance)

A test piece having a size of 20 mm in width and 40 mm in length was cut out from the obtained adhesive sheet and left to stand for 30 minutes in an atmosphere of 23°C-50%RH. Next, under the same atmosphere, the release sheet was peeled off from the test piece, and the transmission spectrum was measured using a spectrophotometer ("V-750" manufactured by Nippon Spectroscopy). The transmittance (UV transmittance) of the pressure-sensitive adhesive sheet at a wavelength of 365 nm was measured. The evaluation criteria are as follows.

◎: UV transmittance of 81% or less, excellent.

(circle): UV transmittance exceeds 81% and 82% or less, good.

x: UV transmittance exceeds 82%, and is not practical.

(Effervescence by ultraviolet (UV) irradiation)

A test piece having a size of 25 mm in width and 100 mm in length was cut out from the obtained adhesive sheet and left to stand for 30 minutes in an atmosphere of 23°C -50%RH. Then, the release sheet was peeled off from the test piece under the same atmosphere, the exposed adhesive layer side of the test piece was attached to an acrylic resin plate ("Acrylate L" manufactured by Mitsubishi Rayon Co., Ltd.), compressed using a 2 kg roll, and left to stand for 24 hours.

Then, using a high-pressure mercury lamp (peak wavelengths: 254 nm, 365 nm, 405 nm, and 435 nm, output: 120 W), ultraviolet (UV) irradiation was performed from the PET sheet side, which is the base sheet, under the condition that the accumulated light amount for the test piece is 1000 mJ. was done. After air-cooling in an atmosphere of 23°C-50%RH for 1 hour, the area of the portion in close contact with the pressure-sensitive adhesive sheet acrylic resin plate was measured, and the adhesion area ratio was obtained according to the following equation. The evaluation criteria are as follows.

[Area ratio of adhesion (%) = [Area of the part in contact (cm2)]/25(cm2)

◎: The adhesion area ratio is 5% or less, excellent.

○: Adhesion area ratio is more than 5% and less than 20%, good.

△: Adhesion area ratio greater than 20% and less than or equal to 70%, possible.

×: The adhesion area ratio exceeds 70%, not practical.

(Easy to peel off by air blow after ultraviolet (UV) irradiation)

A test piece with a width of 100 mm and a length of 100 mm was cut out from the pressure-sensitive adhesive sheet obtained in the same manner as in the evaluation of “difficulty in peeling by air blow before ultraviolet (UV) irradiation” and the release sheet was peeled off, and the exposed adhesive layer side It was attached to an acrylic resin plate and left to stand for 24 hours.

Then, in the same manner as in the evaluation of "foamability by ultraviolet (UV) irradiation", the test piece was irradiated with ultraviolet (UV) light from the PET sheet side, which is the base sheet, and air cooled in an atmosphere of 23°C-50%RH for 1 hour. .

In the same manner as in the evaluation of "difficulty of peeling off by air blow before ultraviolet (UV) irradiation", air was blown to the adherend to which the adhesive sheet after UV irradiation was adhered, and it was confirmed whether the adhesive sheet was peeled off.

The said test was done about 20 test pieces, and the number (peel number) of the test pieces which peeled was investigated. Unlike before UV irradiation, after UV irradiation, the greater the number of peels, the better it can be easily peeled from the adherend, and it is most preferable that the adhesive sheet peels off (that is, the number of peels is 20) for all test pieces.

In addition, the peeling by the said air blow does not require the process of holding the edge part of an adhesive sheet with a hand or a jig|tool, and the process of peeling off an adhesive sheet, and it is considered as natural peeling or a level close to it.

(double-circle): The number of peeling is 20, excellent.

○: The number of peelings is 10 to 19, good.

(triangle|delta): The number of peelings is 1-10, possible.

x: The number of peelings is 0, impractical.

(Self-weight adhesion after ultraviolet (UV) irradiation (difficult to spread wetness))

A test piece having a size of 100 mm in width and 200 mm in length was cut out from the obtained adhesive sheet and left to stand for 30 minutes in an atmosphere of 23°C -50%RH.

Then, in the same manner as in the evaluation of "foamability by ultraviolet (UV) irradiation", the test piece was irradiated with ultraviolet (UV) light from the PET sheet side, which is the base sheet, and air cooled in an atmosphere of 23°C-50%RH for 1 hour. .

Then, in the same atmosphere, the release sheet was peeled from the test piece, and self-weight adhesiveness was evaluated as follows.

Both ends of the adhesive sheet in the longitudinal direction were held with both hands, and the adhesive sheet was curved so that the adhesive layer was facing outward, so that both ends of the adhesive sheet were aligned. In this state, the pressure-sensitive adhesive layer at the center of the pressure-sensitive adhesive sheet was brought into contact with an acrylic resin plate ("Acrylite L" manufactured by Mitsubishi Rayon Co., Ltd.). In this state, the hands holding both ends were released.

30 seconds after releasing the hand, the area of the portion where the pressure-sensitive adhesive sheet is in close contact with the acrylic resin plate was measured, and the adhesion area ratio was obtained according to the following equation. The smaller the adhesion area ratio, the more difficult it is to self-adhere to the acrylic resin plate, and the better it is. The evaluation criteria are as follows.

[Area ratio (%)] = [Area of the part that is in close contact (cm2)]/200(cm2)

◎: The adhesion area ratio after 30 seconds is 0%, excellent.

○: Adhesion area ratio after 30 seconds is greater than 0% and less than or equal to 10%, good.

△: Adhesion area ratio after 30 seconds is more than 10% and less than 100%, possible.

x: The time until the contact area ratio becomes 100% is less than 30 seconds, or the contact area ratio after 30 seconds is 100%, impractical.

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Summary of evaluation results]

All the pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets obtained in Examples 1-28 had a self-weight adhesion time of 15 seconds or less to an acrylic resin plate, and had good wettability and diffusivity to an adherend.

All of the pressure-sensitive adhesive sheets obtained in these Examples had adequate adhesive strength before UV irradiation, had re-peelability capable of being re-attached to an adherend, and had an adhesive strength that was not easily peeled off from the adherend even after air blowing.

All of the adhesive sheets obtained in these Examples had UV transmittance of 20% or more and 82% or less, and had good UV transmittance and UV absorption properties.

In all of the adhesive sheets obtained in these Examples, the formation of gas in the adhesive layer by UV irradiation was clearly observed with the naked eye, and the adhesion area ratio of the adhesive sheet to the adherend was effectively decreased.

In all of the adhesive sheets obtained in these Examples, the radical polymerizable monomer (M) is polymerized by UV irradiation to decrease the adhesive strength and wet diffusivity of the adhesive layer, and at the same time, gas is generated from the adhesive layer, so that it can be avoided only by air blow after UV irradiation. It was able to peel easily from a complex. The peelability after UV irradiation was all natural peeling or a level close to it.

The pressure-sensitive adhesive sheet of Comparative Example 1 using an acrylic pressure-sensitive adhesive containing a radically polymerizable monomer (M) and a gas generator (G) had very high adhesion and poor re-peelability before UV irradiation. Moreover, the self-weight adhesion time with respect to an acrylic resin board before UV irradiation was more than 15 second, and the wet-diffusion property with respect to a to-be-adhered body was unsatisfactory.

The pressure-sensitive adhesive sheet obtained in Comparative Example 2 using the urethane-based pressure-sensitive adhesive containing no radical polymerizable monomer (M) and gas generator (G) had adequate adhesive strength before UV irradiation and had re-peelability to the adherend. It was able to stick with the adhesive force which does not peel off easily from a to-be-adhered body even if it air blows while holding it.

The pressure-sensitive adhesive sheet obtained in this comparative example had a UV transmittance of more than 82% and had poor UV absorptivity.

In addition, since there was no decrease in the adhesive strength and wet diffusivity of the adhesive layer due to polymerization of the radical polymerizable monomer (M) and no gas generation in the adhesive layer when UV irradiated, air blow peeling and wet diffusion after UV irradiation The effect of reducing the sex was not obtained.

The pressure-sensitive adhesive sheet obtained in Comparative Example 3 using a urethane pressure-sensitive adhesive containing a small amount of a gas generator (G) without a radical polymerizable monomer (M) had a UV transmittance of more than 82% and had poor UV absorption.

In this comparative example, since there was little gas generation in the adhesive layer without lowering the adhesive strength and wet diffusivity of the adhesive layer due to polymerization of the radically polymerizable monomer (M) when irradiated with UV light, after UV irradiation, air blow peeling and the effect of reducing wet diffusivity could not be obtained. Since wet diffusivity remains high even if irradiated with UV, even if there is a part peeled by gas generation, it is easy to reattach, and it is thought that the peelability did not improve.

The pressure-sensitive adhesive sheet obtained in Comparative Example 4 using a urethane pressure-sensitive adhesive containing a large amount of a gas generator (G) without containing a radical polymerizable monomer (M) had a lot of gas generation in the pressure-sensitive adhesive layer when irradiated with UV. , since there was no decrease in the adhesive strength and wet diffusivity of the adhesive layer due to polymerization of the radical polymerizable monomer (M), the effect of air blow peeling and wet diffusivity reduction after UV irradiation was not obtained. Since wet diffusivity remains high even if irradiated with UV, even if there is a part peeled by gas generation, it is easy to reattach, and it is thought that the peelability did not improve.

The pressure-sensitive adhesive sheet obtained in Comparative Example 5 using the urethane pressure-sensitive adhesive containing the radical polymerizable monomer (M) and not containing the gas generator (G) had a UV transmittance exceeding 82%, resulting in poor UV absorption.

In this comparative example, when UV irradiation was performed, there was a decrease in the adhesive strength and wet diffusivity of the adhesive layer due to polymerization of the radical polymerizable monomer (M), but since there was no gas generation, the effect of air blow peeling after UV irradiation was obtained. couldn't

The pressure-sensitive adhesive sheet obtained in Comparative Example 6 using a urethane-based pressure-sensitive adhesive in which the amount of radical polymerizable monomer (M) was reduced with respect to Comparative Example 5 without including the gas generator (G) had a UV transmittance of more than 82%, and UV Absorption was poor. In addition, when UV irradiation was carried out, since there was almost no reduction in the adhesive strength and wet diffusivity of the adhesive layer due to polymerization of the radical polymerizable monomer (M) and gas generation in the adhesive layer, after UV irradiation, air blow peeling and wetting The effect of reducing diffusivity was not acquired.

The present invention is not limited to the above embodiments and examples, and design changes can be made as appropriate without departing from the spirit of the present invention.

10,20; adhesive sheet
11,21; material sheet
12,22A,22B; adhesive layer
13,23A,23B; release sheet

Claims (17)

A pressure-sensitive adhesive sheet having a base sheet and an adhesive layer formed on the base sheet and having active energy ray curability,
The adhesive layer is
At least one non-radical polymerizable active hydrogen group-containing compound (HC) having a plurality of active hydrogen groups and not having a (meth)acryloyl group;
At least one radical polymerizable monomer (M) comprising at least one radical polymerizable active hydrogen group-containing monomer (MH) having at least one active hydrogen group and at least two (meth)acryloyl groups;
A polyfunctional isocyanate compound (I), and
It is a coated dried product of an adhesive containing a gas generator (G) that generates gas by irradiation with active energy rays,
The pressure-sensitive adhesive layer is, in accordance with JIS Z0237, using a tensile tester, a peeling rate of 0.3 m/min and an adhesive strength measured under conditions of a peeling angle of 180° of 0.1 to 26 gf/25 mm, the pressure-sensitive adhesive sheet.
According to claim 1,
An adhesive sheet having a transmittance of 1 to 82% at a wavelength of 365 nm.
3. The method of claim 1 or 2,
The adhesive sheet in which content of the gas generating agent (G) in the said adhesive layer is 2 mass % or more.
3. The method of claim 1 or 2,
The said gas generating agent is a nitrogen-element containing compound which contains an N=N bond and produces|generates nitrogen gas by irradiation of an active energy ray, The adhesive sheet.
5. The method of claim 4,
The gas generating agent is at least one selected from the group consisting of an azo compound, an azide compound, a tetrazole compound, a tetrazole compound salt, and a bistetrazole compound.
5. The method of claim 4,
_{The gas generating agent is an adhesive sheet having a N 2} generation volume of 30 to 400 mL/g per 1 g theoretically obtained from the chemical formula.
3. The method of claim 1 or 2,
The at least one active hydrogen group-containing monomer (MH) comprises at least one active hydrogen group-containing monomer (MHF) having at least one active hydrogen group and at least 5 (meth)acryloyl groups.
3. The method of claim 1 or 2,
The at least one radical polymerizable monomer (M) comprises at least one pentafunctional or higher active hydrogen group-containing monomer (MHF) having at least one active hydrogen group and at least five (meth)acryloyl groups,
The adhesive sheet whose total amount of 1 or more types of 5 functional or more radically polymerizable monomers with respect to the total amount of 1 or more types of radically polymerizable monomers (M) is 70-100 mass %.
3. The method of claim 1 or 2,
The active hydrogen group-containing compound (HC) is a reaction product of at least one active hydrogen group-containing compound (HX) having a plurality of active hydrogen groups and at least one polyisocyanate (N), which does not have a (meth)acryloyl group A pressure-sensitive adhesive sheet that is a hydroxyl-terminated urethane prepolymer (UPH).
10. The method of claim 9,
The at least one active hydrogen group-containing compound (HX) is a pressure-sensitive adhesive sheet comprising a polyol having a trifunctional or higher function having three or more hydroxyl groups.
10. The method of claim 9,
The adhesive sheet whose quantity of the radically polymerizable monomer (M) with respect to 100 mass parts of hydroxyl-terminal urethane prepolymer (UPH) is 10-150 mass parts.
10. The method of claim 9,
The adhesive sheet whose quantity of polyfunctional isocyanate compound (I) with respect to 100 mass parts of hydroxyl-terminal urethane prepolymer (UPH) is 5-35 mass parts.
The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the self-weight adhesion time of the pressure-sensitive adhesive layer to the acrylic resin plate measured by the following method is 15 seconds or less:
How to measure self-weight attachment time:
Both ends of the pressure-sensitive adhesive sheet having a width of 100 mm and a length of 200 mm are held with both hands in the longitudinal direction and the pressure-sensitive adhesive sheet is curved so that the pressure-sensitive adhesive layer faces outward, so that both ends of the pressure-sensitive adhesive sheet are aligned. In this state, the pressure-sensitive adhesive layer at the center of the pressure-sensitive adhesive sheet is brought into contact with the acrylic resin plate. In this state, release both hands holding both ends. After releasing both hands, the time until the entire adhesive layer adheres to the acrylic resin plate is measured as the self-weight adhesion time.
3. The method of claim 1 or 2,
Adhesive sheet for surface protection sheet.
An adherend to which the pressure-sensitive adhesive sheet according to claim 1 or 2 is adhered on the adherend.
A step of adhering the pressure-sensitive adhesive sheet to the surface of the adherend;
and irradiating an active energy ray to the pressure-sensitive adhesive sheet adhered to the surface of the adherend to reduce the adhesive force of the pressure-sensitive adhesive sheet,
The use method of the adhesive sheet of Claim 1 or 2.
A step of adhering the pressure-sensitive adhesive sheet to the surface of the adherend;
Self-weight adhesion time of the adhesive layer to the acrylic resin plate measured by the following method after irradiation with active energy rays by irradiating active energy rays to the adhesive sheet adhered to the surface of the adherend to lower the adhesive force of the adhesive sheet A method of using the pressure-sensitive adhesive sheet according to claim 1 or 2, comprising a step of peeling the pressure-sensitive adhesive sheet having reduced adhesive strength from the adherend for 30 seconds or longer:
How to measure self-weight attachment time:
Both ends of the pressure-sensitive adhesive sheet having a width of 100 mm and a length of 200 mm are held with both hands in the longitudinal direction, and the pressure-sensitive adhesive sheet is curved so that the pressure-sensitive adhesive layer faces outward, so that both ends of the pressure-sensitive adhesive sheet are aligned. In this state, the pressure-sensitive adhesive layer at the center of the pressure-sensitive adhesive sheet is brought into contact with the acrylic resin plate. In this state, release both hands holding both ends. After releasing both hands, the time until the entire adhesive layer adheres to the acrylic resin plate is measured as the self-weight attachment time.

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