JP7241538B2 - Adhesive composition, cured product and surface protection film - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive composition, a cured product and a surface protection film.

Various displays such as word processors, computers, mobile phones, and televisions, various optical components such as polarizing plates or similar laminates, and various substrates such as electronic substrates are usually coated with an adhesive layer for the purpose of surface protection. A surface protective film having a surface is laminated.

The pressure-sensitive adhesive layer is required to have good adhesiveness in a bonded state. Adhesiveness refers to the property of having sufficient adhesive strength to an adherend and not causing problems such as peeling and lifting. In addition, the surface protection film is peeled off from the adherend during the manufacturing process or during use. Adhesive residue may occur on the body. Therefore, the pressure-sensitive adhesive layer is required to have good reworkability (removability) at the time of peeling. Reworkability refers to the property of being able to be easily peeled off without destroying the adherend or leaving adhesive residue on the adherend.

From the viewpoint of compatibility between such adhesiveness and reworkability, urethane-based adhesive compositions are being studied as adhesive compositions.

In Patent Documents 1 and 2, a pressure-sensitive adhesive layer formed from an adhesive composition containing a hydroxyl group-containing polyurethane, an ionic compound, and a trifunctional isocyanate compound improves the adhesive strength and reworkability of the pressure-sensitive adhesive film. It is disclosed that both of

Patent Document 3 discloses that reworkability can be improved by a pressure-sensitive adhesive layer formed from an adhesive composition containing a urethane urea resin having a terminal hydroxyl group, an ionic compound, and a polyfunctional isocyanate. It is

JP 2007-169377 A JP 2005-154492 A JP 2007-238766 A

The pressure-sensitive adhesive layers formed from the urethane-based adhesive compositions (pressure-sensitive adhesive compositions) disclosed in Patent Documents 1 to 3 attempt to achieve both adhesion and reworkability by adjusting the adhesive force. However, in this method, both adhesiveness and reworkability are dependent on the adhesive strength of the adhesive layer, resulting in a trade-off relationship. That is, the problem is that if sufficient reworkability is to be obtained, the adhesiveness will be insufficient, and if sufficient adhesiveness is to be obtained, the reworkability will be insufficient. In addition, the urethane-based adhesive composition may have problems such as insufficient punching workability, insufficient substrate contamination resistance, and increased peeling electrification voltage. Depending on the type of urethane compound contained in the urethane adhesive composition, the wettability of the pressure-sensitive adhesive layer to the adherend may be insufficient. At this time, there arises a problem that air enters during lamination with the adherend, resulting in lamination failure.

Accordingly, an object of the present invention is to provide a means that enables the formation of a pressure-sensitive adhesive layer that achieves both high levels of adhesiveness and reworkability by reducing the adhesive strength at the time of peeling below the adhesive strength in the adhesive state. and Further, in addition to achieving both adhesiveness and reworkability, the present invention improves the punching workability of the adhesive layer and the substrate contamination resistance, reduces the peeling electrification voltage of the adhesive layer, and improves the adhesion of the adhesive layer. An object of the present invention is to provide a means capable of realizing high wettability and high transparency to an adherend.

The above problems of the present invention are solved by the following means.

(A) component: a urethane prepolymer having two or more hydroxyl groups,
(B) component: polyfunctional (meth)acrylate,
(C) component: a cross-linking agent,
(D) component: crosslinked particles,
(E) component: photoradical initiator, and (F) component: antistatic agent,
contains
The pressure-sensitive adhesive composition, wherein the content of component (D) with respect to 100 parts by mass of component (A) is 0.01 parts by mass or more and 10 parts by mass or less.

According to the present invention, a means is provided that enables the formation of a pressure-sensitive adhesive layer that achieves both a high level of pressure-sensitive adhesiveness and reworkability by reducing the pressure-sensitive adhesive strength at the time of peeling below the pressure-sensitive adhesive strength in the adhesive state. Further, according to the present invention, in addition to achieving both adhesiveness and reworkability, the punching workability of the adhesive layer and the substrate contamination resistance are improved, the peeling electrostatic voltage of the adhesive layer is reduced, and the adhesive layer provides a means capable of realizing high wettability and high transparency to adherends.

FIG. 3 is an explanatory diagram illustrating a method for measuring the wettability of the pressure-sensitive adhesive layer to an adherend in Examples.

Preferred embodiments of the present invention are described below. Unless otherwise specified, the operation, physical properties, etc. are measured under the conditions of room temperature (20° C. or higher and 25° C. or lower)/relative humidity of 40% RH or higher and 50% RH or lower.

In this specification, "(meth)acrylate" is a generic term for acrylate and methacrylate. Similarly, compounds containing (meth) such as (meth)acrylic acid are collective names for compounds having "meta" in their names and compounds not having "meta" in their names.

Further, in the present specification, "(co)polymer" is a generic term for homopolymers and copolymers.

<Adhesive composition>
One aspect of the present invention is
(A) component: a urethane prepolymer having two or more hydroxyl groups,
(B) component: polyfunctional (meth)acrylate,
(C) component: a cross-linking agent,
(D) component: reactive surface modifier,
(E) component: photoradical initiator, and (F) component: antistatic agent,
contains
The content of the component (D) with respect to 100 parts by mass of the component (A) is 0.01 parts by mass or more and 10 parts by mass or less.

The present inventors presume the mechanism by which the above configuration solves the problem as follows.

A urethane-based pressure-sensitive adhesive composition generally forms a pressure-sensitive adhesive layer by curing a urethane-based compound contained in the composition and a cross-linking agent such as an isocyanate compound through polymerization and a cross-linking reaction. In conventional urethane-based pressure-sensitive adhesive compositions such as those disclosed in Patent Documents 1 to 3, adhesiveness and reworkability are improved by adjusting the type of urethane-based compound or cross-linking agent, their content ratio, or reaction conditions. trying to control. However, since both adhesiveness and reworkability depend on the adhesive strength of the adhesive layer, there is a trade-off relationship, and there is a problem that it is difficult to achieve both high levels of adhesiveness and reworkability. rice field.

On the other hand, the pressure-sensitive adhesive composition according to one embodiment of the present invention contains component (A): a urethane prepolymer having two or more hydroxyl groups and component (C): a cross-linking agent. And the adhesive composition which concerns on one form of this invention further contains (B) component: polyfunctional (meth)acrylate and (E) component: photoradical initiator in addition to these. Therefore, by irradiating with light during rework, the photopolymerization and crosslinking reaction of the component (B): polyfunctional (meth)acrylate and the (meth)acrylic (co)polymer derived from this proceed. , the adhesive strength of the adhesive is greatly reduced. As a result, the pressure-sensitive adhesive layer composed of the cured product of the pressure-sensitive adhesive composition according to one embodiment of the present invention has good adhesive strength before light irradiation and also has extremely good reworkability. Become. Thus, the pressure-sensitive adhesive composition according to one embodiment of the present invention overcomes the technical problem of the trade-off relationship between the adhesiveness and reworkability of conventional urethane-based pressure-sensitive adhesive compositions. It is. That is, the pressure-sensitive adhesive composition according to one embodiment of the present invention is based on a completely different design concept from conventional urethane-based pressure-sensitive adhesive compositions. It makes it possible.

Moreover, the adhesive composition which concerns on one form of this invention contains (D) component: crosslinked particle. Here, the component (D) forms irregularities on the surface of the pressure-sensitive adhesive layer. Then, the adhesive strength is lowered due to the unevenness formed in the adhesive layer. As a result, the adhesive strength of the adhesive layer before light irradiation is within an appropriate range, and the adhesiveness is improved. In addition, the adhesive strength of the adhesive layer during rework is lowered, and the reworkability of the adhesive layer and the adhesive film having the same is improved.

Furthermore, the pressure-sensitive adhesive composition according to one aspect of the present invention has a content of the component (D) within a predetermined range. That is, the content of component (D) is sufficient to obtain the above effects, and is not excessive. Therefore, it is possible to achieve both adhesiveness and reworkability while suppressing deterioration in the wettability and transparency of the adhesive layer to the adherend caused by the component (D). Also, since the amount of component (D) added is not excessive, component (D) is less likely to come off, and good punching workability can be obtained. In addition, a low peeling withstand voltage is achieved without exacerbating the bleed-out of the component (F), and good substrate contamination resistance is maintained.

It should be noted that the above mechanism is based on speculation, and its correctness or wrongness does not affect the technical scope of the present invention.

The pressure-sensitive adhesive composition according to one aspect of the present invention is preferably heat-cured to form a pressure-sensitive adhesive layer. That is, the pressure-sensitive adhesive composition according to one aspect of the present invention is preferably a thermosetting pressure-sensitive adhesive composition. The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to one aspect of the present invention is composed of a cured product, preferably a thermoset product, of the pressure-sensitive adhesive composition according to one aspect of the present invention. In addition, in this specification, a thermoset is a hardened|cured material formed by the cross-linking reaction progressing by heat. A thermoset does not necessarily require heating, and includes a cured product cured at room temperature (20° C. or higher and 25° C. or lower).

Moreover, one preferable aspect of the present invention relates to a pressure-sensitive adhesive composition in which the adhesive strength of the pressure-sensitive adhesive composition is reduced by light irradiation. Here, "light irradiation lowers the adhesive strength of the pressure-sensitive adhesive composition" means that light irradiation lowers the adhesive strength of the pressure-sensitive adhesive composition itself and its cured product. Therefore, the pressure-sensitive adhesive composition exhibits extremely good adhesiveness in an adhesive state, and exhibits remarkably excellent reworkability by performing light irradiation treatment during rework. Here, the ratio of the adhesive strength after light irradiation to the adhesive strength before light irradiation treatment of the cured product of the adhesive composition, and the adhesive strength before and after light irradiation are the same as those for the adhesive layer and adhesive film described later. is preferably in the range of

Each component constituting the pressure-sensitive adhesive composition according to one embodiment of the present invention will be described in detail below.

[(A) component: urethane prepolymer having two or more hydroxyl groups]
A pressure-sensitive adhesive composition according to one aspect of the present invention contains component (A): a urethane prepolymer having two or more hydroxyl groups. The component (A) has a function of imparting adhesiveness to the adhesive layer composed of the cured adhesive composition. Such component (A) can contribute to the formation of the pressure-sensitive adhesive layer by progressing polymerization (preferably thermal polymerization) and cross-linking.

More specifically, the position of the hydroxyl group in the molecule of component (A) is not particularly limited, but it is preferred that component (A) has hydroxyl groups at least at both ends. Component (A) is not particularly limited as long as it is a urethane prepolymer that satisfies these requirements, and known ones can be used.

It is widely known that a urethane prepolymer can be obtained by reacting a component having two or more hydroxyl groups (for example, a polyol component) with a polyfunctional isocyanate component. Here, the (A) component includes, for example, those obtained by reacting the (a1) component: polyol and the (a2) component: polyfunctional isocyanate.

Component (a1) is not particularly limited, and known polyols can be used. For example, known polyether polyols, known polyether polyols, known polyester polyols, known polycarbonate polyols, known polybutadiene polyols, known polyisoprene polyols, and the like can be used. These may be used alone or in combination of two or more. When two or more types are used, two or more of the same system may be combined, or one or more of different systems may be combined. The number of hydroxyl groups in these polyols is not particularly limited, but is preferably in the range of 2 or more and 4 or less per molecule.

Examples of polyether polyols include polyether polyols having repeating structures such as methylene oxide chains, ethylene oxide chains, propylene oxide chains, and alkylene oxide chains such as butylene oxide chains. Alkylene oxide chains may be used alone or in combination of two or more. Among these, those having a hydroxyl group bonded to a primary carbon atom are preferred from the viewpoint of excellent reactivity with isocyanate groups. Specific examples include, but are not limited to, polyethylene glycol, polypropylene glycol, terminal polyethylene glycol capped polypropylene glycol, polytetramethylene glycol, and the like.

Examples of polyester polyols include those composed of a known acid component and a known alcohol component. Examples of acid components include adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, terephthalic acid, and trimellitic acid. Examples of alcohol components include ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, Neopentyl glycol, butylethylpropanediol, glycerin, trimethylolpropane, pentaerythritol and the like. Each of the acid component and the alkali component may be used alone or in combination of two or more. Other examples of polyester polyols include those obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valerolactone) and polyvalerolactone.

Examples of polycarbonate polyols include those obtained by reacting a known carbonate ester or phosgene with a known compound having two or more hydroxyl groups. Carbonic esters include, for example, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate and the like. Examples of compounds having two or more hydroxyl groups include aliphatic polyols, alicyclic polyols, and aromatic polyols. Examples of aliphatic polyols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1 ,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3-propane diol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8 - octanediol and the like. Alicyclic polyols include, for example, 1,2-cyclobutanediol, 1,3-cyclopentanediol, 1,4-cyclohexanedimethanol, cycloheptanediol, cyclooctanediol, and hydroxypropylcyclohexanol. Examples of aromatic polyols include bisphenol A, bisphenol F, 4,4'-biphenol and the like. Carbonic acid esters and compounds having two or more hydroxyl groups may be used alone or in combination of two or more.

Although the number average molecular weight of component (a1) is not particularly limited, it is preferably 700 or more and 5,000 or less. Further, the number average molecular weight of component (a1) is more preferably 1,000 or more and 4,000 or less. Within the above range, reaction control during synthesis becomes easier. The number average molecular weight of the component (a1) can be obtained as a polystyrene-equivalent value by gel permeation chromatography (GPC).

Also, if necessary, part of the component (a1) may be replaced with low-molecular-weight polyols or polyvalent amines. Examples of low-molecular-weight polyols include ethylene glycol, 1,4-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, butylethylpropanediol, Glycerin, trimethylolpropane, pentaerythritol, dimer diol, castor oil polyol and the like. Examples of polyvalent amines include ethylenediamine, N-aminoethylethanolamine, isophoronediamine, and xylylenediamine.

Component (a2) is not particularly limited, and known polyfunctional isocyanates can be used. Examples thereof include aromatic diisocyanates such as xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate and naphthalene diisocyanate. Further examples include aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, diisocyanatomethylcyclohexane, and tetramethylxylylene diisocyanate. . Furthermore, adducts, burettes, isocyanurates and the like of these diisocyanates are included. A polyfunctional isocyanate compound may be used individually and may be used in combination of 2 or more type. Among these, aliphatic or alicyclic diisocyanates are preferable from the viewpoint of suppressing discoloration, and aliphatic diisocyanates are more preferable from the viewpoint of easier reaction control during synthesis.

Component (A) preferably contains a urethane prepolymer having a polyether skeleton and two or more hydroxyl groups. Due to its molecular structure, the polyether skeleton has the function of imparting high wettability to various adherends such as glass. Therefore, when the urethane polymer is used, the wettability of the pressure-sensitive adhesive layer to the adherend is further improved compared to when other urethane prepolymers are used.

More specifically, the urethane prepolymer having a polyether skeleton and two or more hydroxyl groups is a urethane oligomer or polyurethane containing two or more hydroxyl groups in one molecule and having a polyether structure as part of the main chain. be. A polyether structure represents, for example, a repeating structure of alkylene oxide chains such as a methylene oxide chain, an ethylene oxide chain, a propylene oxide chain, and a butylene oxide chain.

Among urethane prepolymers having a polyether skeleton and two or more hydroxyl groups, urethane prepolymers having a polyether skeleton and two or more hydroxyl groups and (meth)acryloyloxy groups are more preferred. According to the urethane prepolymer, the reworkability of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer is further improved. It is presumed that this is because the photopolymerization and cross-linking reaction of component (A) or component (A) with component (B) or its (co)polymer described below proceeds due to component (E) described later. ing. The position of the (meth)acryloyloxy group in the urethane prepolymer molecule is not particularly limited, but it is preferable to have the (meth)acryloyloxy group as a side chain. According to the urethane prepolymer, the effect of improving the reworkability of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer is enhanced.

Urethane prepolymers having a polyether skeleton and two or more hydroxyl groups are not particularly limited, and known ones can be used. Examples thereof include those obtained by reacting a polyether polyol, which is one of the component (a1), with the component (a2).

Moreover, the urethane prepolymer having a polyether skeleton and two or more hydroxyl groups and (meth)acryloyloxy groups is not particularly limited, and known ones can be used. For example, one obtained by reacting component (a1), component (a2), and component (a3): a (meth)acrylate compound having a hydroxyl group or an isocyanate group (a compound having a (meth)acryloyloxy group) mentioned. Here, component (a3) is used for the purpose of introducing a (meth)acryloyloxy group into component (A).

Component (a3) is not particularly limited, and known (meth)acrylate compounds having a hydroxyl group or an isocyanate group can be used. Among these, a (meth)acrylate compound having a hydroxyl group is preferable from the viewpoint of availability of raw materials, curability and adhesive properties.

(Meth)acrylate compounds having a hydroxyl group include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4 - hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, hydroxyethylacrylamide, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, polyethylene glycol mono Acrylate, polypropylene glycol monoacrylate, and the like.

(Meth)acrylate compounds having an isocyanate group include, for example, 2-(meth)acryloyloxyethyl isocyanate, 2-(2-(meth)acryloyloxyethyloxy)ethyl isocyanate, 1,1-bis((meth)acryloyl oxymethyl)ethyl isocyanate and the like.

As the urethane prepolymer having a polyether skeleton and two or more hydroxyl groups and (meth)acryloyloxy groups, the following may also be used. For example, those obtained by reacting the component (a1) with a compound having two or more isocyanate groups, which is a reaction product of a trifunctional or higher polyfunctional isocyanate and a (meth)acrylate compound having a hydroxyl group. is mentioned. Here, the polyfunctional isocyanate having a functionality of 3 or more is not particularly limited, and for example, the same compounds as those shown in the section of component (C) described later can be used. Moreover, the (meth)acrylate compound having a hydroxyl group is not particularly limited, and for example, the same compound as the above component (a3) can also be used. Alternatively, for example, it can be obtained by reacting the above component (a2) with a compound having two or more hydroxyl groups, which is a reaction product of a trifunctional or higher polyol and a (meth)acrylate compound having an isocyanate group. things are mentioned. Here, the tri- or more functional polyol is not particularly limited, and for example, the same compounds as those shown in the section of component (a1) above can be used. Also, the (meth)acrylate compound having an isocyanate group is not particularly limited, and for example, the same compound as the above component (a3) can be used.

Although the number average molecular weight of component (A) is not particularly limited, it is preferably 1,000 or more. The number average molecular weight of component (A) is more preferably 20,000 or more and 500,000 or less, even more preferably 50,000 or more and 200,000 or less. Within the above range, the viscosity of the pressure-sensitive adhesive composition will be in a more appropriate range, and the workability will be further improved.

(A) The number average molecular weight of the component can be calculated, for example, by the following method. 10 mg of the component (A) and 10 ml of THF are added to the sample bottle, allowed to stand overnight for dissolution, and filtered through a PTFE cartridge filter (0.5 μm) to obtain a sample. RI detector RI8020 (manufactured by Tosoh Corporation) is used as a detector, and TSKgelGMR-HHRL (manufactured by Tosoh Corporation) x 2 in series and HLC-8020GPC (manufactured by Tosoh Corporation) are used as measurement columns. The measurement conditions are a column temperature of 40° C., a flow rate of 1.0 ml/min, and a solvent of THF, and the number average molecular weight is analyzed as a cubic curve calibration curve using standard polystyrene manufactured by Tosoh Corporation.

Although the hydroxyl value of component (A) is not particularly limited, it is preferably 1 mg·KOH/g or more and 230 mg·KOH/g or less. The hydroxyl value of component (A) is more preferably 3 mg·KOH/g or more and 150 mg·KOH/g or less, and more preferably 4 mg·KOH/g or more and 100 mg·KOH/g or less. Within the above range, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer have a more appropriate adhesive force, and the effect of reducing the occurrence of detachment of the pressure-sensitive adhesive layer is further improved. It is presumed that this is because the progress of the polymerization and cross-linking reaction between the component (A) and the component (C), which will be described later, becomes more appropriate. Incidentally, the hydroxyl value can be determined by measurement according to JIS K0070:1992. Here, the hydroxyl value of the component (A) can be an index of the content of hydroxyl groups.

The double bond equivalent (polymer mass (g) per 1 mol of double bond) of component (A) is not particularly limited, but is preferably 30,000 g/mol or less. Further, the double bond equivalent of component (A) is more preferably 20,000 g/mol or less, more preferably 10,000 g/mol or less. Although the double bond equivalent of component (A) is not particularly limited, it is preferably 1,000 g/mol or more. Within the above range, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer have a more appropriate adhesive strength, and the pressure-sensitive adhesive layer is less likely to come off. It is presumed that this is because the photopolymerization and crosslinking reaction of component (A), or between component (A) and component (B) or their (co)polymers, by component (E) described later, proceeds more appropriately. are doing. Here, when the component (A) has a (meth)acryloyloxy group, the double bond equivalent of the component (A) can be an indicator of the content of the (meth)acryloyloxy group.

The component (A) may be a synthetic product or a commercial product.

The method for producing the component (A) is not particularly limited, and known methods for synthesizing urethane compounds can be used. Among these, it is preferable to use a known urethanization reaction and apply conditions in which hydroxyl groups are excessive. As the component (A) and its production method, known compounds and known production methods described in JP-A-2005-169377 and JP-A-2007-168377 may be used. Moreover, when manufacturing the component (A), a known polymerization inhibitor, a known urethanization catalyst, and the like may be used as necessary.

As commercial products, for example, Toyo Ink Co., Ltd. SIAVINE (registered trademark) SH101, Neagari Kogyo Co., Ltd. Artresin (registered trademark) UN5500, UN5500P, etc. can be used.

The urethane prepolymers constituting component (A) may be used alone or in combination of two or more.

[(B) component: polyfunctional (meth)acrylate]
The pressure-sensitive adhesive composition according to one aspect of the present invention contains component (B): polyfunctional (meth)acrylate (B). The component (B) is photopolymerized by light irradiation and has a function of performing a cross-linking reaction, and thus can contribute to improvement of reworkability due to reduction in adhesive strength after light irradiation. When the component (B) is not contained, the adhesive strength is not lowered by light irradiation, resulting in insufficient reworkability.

Component (B) is not particularly limited as long as it is a compound containing two or more (meth)acryloyloxy groups in one molecule. Among these, bifunctional or more and 10 or less functional (meth)acrylates are preferable examples. The component (B) may also be a (meth)acrylate having 11 or more functionalities, such as polypentaerythritol poly(meth)acrylate having 11 or more functionalities.

Examples of bifunctional (meth)acrylates include dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate. ) acrylate, neopentyl glycol di(meth)acrylate, propylene oxide-modified neopentyl glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, dicyclopentanyl Di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, polyethylene glycol di(meth)acrylate, modified bisphenol A di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, ethylene oxide-modified phosphoric acid Di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, pentaerythritol di(meth)acrylate, dipentaerythritol di(meth)acrylate, tripentaerythritol di(meth)acrylate, tetra pentaerythritol di(meth)acrylate and the like.

Trifunctional (meth)acrylates include, for example, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, tripentaerythritol tri(meth)acrylate, tetrapentaerythritol tri(meth)acrylate, propionic acid-modified di Pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxy tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate , polyether tri(meth)acrylate, glycerin propoxy tri(meth)acrylate, tris(acryloxyethyl) isocyanurate, and the like.

Examples of tetrafunctional (meth)acrylates include pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, tripentaerythritol tetra(meth)acrylate, tetrapentaerythritol tetra(meth)acrylate, pentaerythritol ethoxytetra (Meth)acrylate, ditrimethylolpropane tetra(meth)acrylate and the like.

Pentafunctional (meth)acrylates include, for example, dipentaerythritol penta(meth)acrylate, tripentaerythritol penta(meth)acrylate, tetrapentaerythritol penta(meth)acrylate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol monohydroxy penta(meth)acrylate and the like.

Examples of hexafunctional (meth)acrylates include dipentaerythritol hexa(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tetrapentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and the like. mentioned.

Examples of heptafunctional (meth)acrylates include tripentaerythritol hepta(meth)acrylate and tetrapentaerythritol hepta(meth)acrylate.

Examples of octafunctional (meth)acrylates include tripentaerythritol octa(meth)acrylate and tetrapentaerythritol octa(meth)acrylate.

Examples of 9-functional (meth)acrylates include tetrapentaerythritol nona(meth)acrylate.

Examples of the 10-functional (meth)acrylate include tetrapentaerythritol deca(meth)acrylate.

Among these, trifunctional (meth)acrylates are preferred, trimethylolpropane tri(meth)acrylate is more preferred, and trimethylolpropane triacrylate is even more preferred.

As the compound containing two or more (meth)acryloyloxy groups in one molecule, urethane (meth)acrylate, polyester (meth)acrylate, and the like may be used.

Urethane (meth)acrylate is not particularly limited. Examples thereof include monomers and oligomers obtained by reacting a diisocyanate, a polyol, and a (meth)acrylate compound having a hydroxyl group. Urethane (meth)acrylates include, for example, urethane (meth)acrylates described in JP-A-2002-265650, JP-A-2002-355936, JP-A-2002-067238, and the like.

Diisocyanates include, for example, TDI, MDI, HDI, IPDI, HMDI and the like.

Examples of polyols include poly(propylene oxide) diol, poly(tetramethylene oxide) diol, ethoxylated bisphenol A, ethoxylated bisphenol S spiroglycol, caprolactone-modified diol, carbonate diol and the like.

(Meth)acrylate compounds having a hydroxyl group include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, glycidol di(meth)acrylate, pentaerythritol triacrylate and the like.

A specific urethane (meth)acrylate is not particularly limited. For example, an adduct of TDI with hydroxyethyl acrylate, an adduct of IPDI with hydroxyethyl acrylate, an adduct of HDI with pentaerythritol triacrylate (PETA), an adduct of TDI with PETA, and the remaining isocyanate and dodecyloxyhydroxypropyl acrylate, an adduct of 6,6 nylon and TDI, an adduct of pentaerythritol, TDI and hydroxyethyl acrylate.

Polyester (meth)acrylate is an acrylate obtained by condensing (meth)acrylic acid with a hydroxyl group remaining in a polyester skeleton synthesized from a polyol and a dibasic acid.

A specific polyester acrylate is not particularly limited. Examples thereof include a reaction product of phthalic anhydride/propion oxide/acrylic acid, a reaction product of adipic acid/1,6-hexanediol/acrylic acid, and a reaction product of trimellitic acid/diethylene glycol/acrylic acid.

Moreover, it is preferable that the (B) component further contains a hydroxyl group. By having this structure, the occurrence of detachment of the pressure-sensitive adhesive layer is further reduced. During the polymerization and crosslinking reaction of the component (A) and the component (C), the polymerization and crosslinking reaction of the component (A), the component (B) or its (co)polymer, and the component (C) I'm assuming it's going on.

Although the hydroxyl value of component (B) is not particularly limited, it is preferably 100 mg·KOH/g or less. Further, the hydroxyl value of component (B) is more preferably 50 mg·KOH/g or less, more preferably 30 mg·KOH/g or less. (Lower limit 0 mg·KOH/g) Within the above range, the adhesive strength of the adhesive layer and the adhesive film having the adhesive layer is in a more appropriate range, and the occurrence of detachment of the adhesive layer is further reduced. The progress of polymerization and crosslinking reaction between component (B) or its (co)polymer and component (C) is in a moderate range, and the polymerization and crosslinking reaction between component (A) and component (C) are more favorable. It is speculated that this is because it progresses to Incidentally, the hydroxyl value can be determined by measurement according to JIS K0070:1992.

The component (B) may be a synthetic product or a commercial product. Commercially available products include A-TMPT, A-TMM-3, A-TMM-3L, A-TMM-3LM-N, ATM-35E, A-TMMT, and A-9550 manufactured by Shin-Nakamura Chemical Co., Ltd. , A-DPH, Aronix (registered trademark) M-305, M-402, M-405 manufactured by Toagosei Co., Ltd., Viscoat (registered trademark) #295 manufactured by Osaka Organic Chemical Industry Co., Ltd., TMPTA, #802, TriPEA etc.

Polyfunctional (meth)acrylates may be used alone or in combination of two or more.

The content of component (B) in the pressure-sensitive adhesive composition (the total amount when two or more are included) is not particularly limited, but is 1 part by mass or more and 500 parts by mass or less per 100 parts by mass of component (A). Preferably. Further, the content of component (B) is more preferably 5 parts by mass or more and 250 parts by mass or less with respect to 100 parts by mass of component (A). Further, the content of component (B) is more preferably 10 parts by mass or more and 150 parts by mass or less per 100 parts by mass of component (A). Within the above range, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer are in a more appropriate range. It is presumed that this is because the content ratio of the component (A) and the component (B) is in an appropriate range, so that the adhesive strength is in a more favorable range. Further, within the above range, the reworkability of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer is further improved. It is presumed that this is because the photopolymerization and cross-linking reaction of the component (B) proceed further due to light irradiation during reworking. Furthermore, within the above range, when the component (B) further has a hydroxyl group, the occurrence of detachment of the pressure-sensitive adhesive layer is further reduced. During the polymerization and crosslinking reaction of the component (A) and the component (C), the polymerization and crosslinking reaction of the component (A), the component (B) or its (co)polymer, and the component (C) I'm assuming it's going on.

Therefore, as a preferred example of component (B), the content of component (B) with respect to 100 parts by mass of component (A) is 10 parts by mass or more and 150 parts by mass or less, and the hydroxyl value of component (B) is 100 mg·KOH/g or less.

[(C) component: cross-linking agent]
The pressure-sensitive adhesive composition according to one aspect of the present invention contains component (C): a cross-linking agent. Component (C) has the function of promoting polymerization (preferably thermal polymerization) and cross-linking with component (A). For this reason, the adhesive strength of the adhesive composition and the adhesive strength after light irradiation are set in appropriate ranges, which can contribute to compatibility between adhesiveness and reworkability. If the component (C) is not contained, the adhesive strength becomes excessive and the reworkability becomes insufficient.

Component (C) is not particularly limited as long as it can promote polymerization and cross-linking reaction with component (A). Examples thereof include isocyanate-based cross-linking agents, carbodiimide-based cross-linking agents, oxazoline-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, and peroxides. Here, the peroxide means a compound having a peroxide structure "--O--O--" in its molecular structure. These may be used alone or in combination of two or more. When two or more types are used, two or more of the same system may be combined, or one or more of different systems may be combined.

The isocyanate-based cross-linking agent is not particularly limited, and known compounds having an isocyanate group (isocyanate compounds) can be used. Compounds having an isocyanate group include monofunctional isocyanates and polyfunctional isocyanates. Among these, polyfunctional isocyanates are preferred. Examples of polyfunctional isocyanates include bifunctional isocyanates (compounds having two isocyanate groups) and trifunctional or higher isocyanates (compounds having three or more isocyanate groups).

Examples of bifunctional isocyanates include aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, carbodiimide-modified diisocyanates of these diisocyanates, or these diisocyanates at the main chain end, side chain, or side chain end. and polymer compounds having

Aliphatic diisocyanates include 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, and norbornane diisocyanatomethyl (NBDI).

Examples of alicyclic diisocyanates include transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI), H12-MDI (hydrogenated MDI) and the like.

Examples of aromatic diisocyanates include dimer acid diisocyanate, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), and 4,4'-diphenylmethane diisocyanate. (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethylxylidene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1,5-naphthalenediisocyanate (NDI) and the like.

Examples of tri- or higher functional isocyanates include isocyanurate compounds obtained by polycondensation of the above bifunctional isocyanates to isocyanurate modification, adduct products obtained by adduct modification of the above bifunctional isocyanates, and the above bifunctional isocyanates with glycerin, trimethylolpropane, and the like. A biuret compound obtained by biuret-modifying a trihydric alcohol, the above bifunctional isocyanate, or an adduct thereof, a biuret compound, or an isocyanurate compound at the main chain end, side chain, or side chain end.

The carbodiimide-based cross-linking agent is not particularly limited, and known carbodiimide compounds can be used. Carbodiimide compounds include, for example, high-molecular-weight polycarbodiimide produced by decarboxylation condensation reaction of diisocyanate in the presence of a carbodiimidation catalyst. Diisocyanates to be subjected to the decarboxylation condensation reaction include, for example, 4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, and 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-tolylene diisocyanate, 1-methoxyphenyl-2,4- diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate and the like. Carbodiimidation catalysts used in the decarboxylation condensation reaction include, for example, 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2 -phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, phosphorene oxides such as these 3-phospholene isomers, and the like.

The oxazoline-based cross-linking agent is not particularly limited, and known oxazoline compounds can be used. Examples of oxazoline compounds include oxazoline group-containing polymers. Specific examples of oxazoline compounds include oxazoline group-containing acrylic polymers and oxazoline group-containing acrylic/styrene polymers. The oxazoline group-containing acrylic polymer includes, for example, an oxazoline group-containing acrylic polymer containing a main chain composed of an acrylic skeleton and having an oxazoline group in a side chain of the main chain. Further, the oxazoline group-containing acrylic/styrene polymer includes, for example, an oxazoline group-containing acrylic/styrene polymer containing a main chain composed of an acrylic skeleton or a styrene skeleton and having an oxazoline group in the side chain of the main chain. is mentioned. Examples of the oxazoline group include 2-oxazoline group, 3-oxazoline group, 4-oxazoline group and the like.

The epoxy-based cross-linking agent is not particularly limited, and known epoxy compounds can be used. Examples of epoxy compounds include liquid epoxy compounds. A liquid epoxy compound is preferable because it facilitates mixing operation when producing the pressure-sensitive adhesive composition.

The aziridine-based cross-linking agent is not particularly limited, and known aziridine compounds can be used. Examples of aziridine compounds include polyfunctional aziridine compounds having multiple aziridine rings. As polyfunctional aziridine compounds, for example, US Pat. No. 3,225,013, US Pat. Compounds disclosed in JP-A No. 104970 and the like can be mentioned. As the polyfunctional aziridine compound, a trifunctional aziridine compound (compound having three aziridine rings) can be preferably used. Trifunctional aziridine compounds include, for example, trimethylolpropane tris[3-aziridinylpropionate], trimethylolpropane tris[3-(2-methyl-aziridinyl)-propionate], trimethylolpropane tris[2-aziridinyl lysinyl butyrate], pentaerythritol tris-3-(1-aziridinylpropionate), and pentaerythritol tetrakis-3-(1-aziridinylpropionate).

Peroxides are not particularly limited, and known ones can be used. Peroxides include, for example, diisopropyl peroxydicarbonate, bis(2-ethylhexyl) peroxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate (also known as bis(4-t-butyl peroxydicarbonate) cyclohexyl), bis-sec-butyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, bis-n-octanoyl Peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, bis(4-methylbenzoyl)peroxide, dibenzoyl peroxide (benzoyl peroxide), t-butyl peroxybutyrate etc.

Among these, an isocyanate-based cross-linking agent or a peroxide is preferred, and an isocyanate-based cross-linking agent is more preferred. Further, it is more preferable to use an isocyanate-based cross-linking agent alone, or to use an isocyanate-based cross-linking agent and a peroxide in combination.

Examples of isocyanate-based cross-linking agents include hexamethylene diisocyanate (HDI) or pentamethylene diisocyanate (PDI), adducts, biurets or isocyanurates thereof, or high molecular weight compounds having these at the main chain end, side chain, or side chain end. Molecular compounds are preferred. As the isocyanate-based cross-linking agent, an adduct of hexamethylene diisocyanate (HDI) or pentamethylene diisocyanate (PDI) is more preferable. Alternatively, a polymer compound obtained by a condensation reaction between hexamethylene diisocyanate (HDI) or pentamethylene diisocyanate (PDI) and a diol is more preferable. Preferred examples of hexamethylene diisocyanate (HDI) include 1,6-hexamethylene diisocyanate. Preferred examples of pentamethylene diisocyanate (PDI) include 1,5-pentamethylene diisocyanate. These isocyanate cross-linking agents allow the progress of the polymerization and cross-linking reactions with the component (A) to proceed more efficiently.

A preferred peroxide is bis(4-t-butylcyclohexyl)peroxydicarbonate. According to the peroxide, the progress of polymerization and cross-linking reaction with the component (A) can be carried out more efficiently.

Component (C) may be a synthetic product or a commercial product. Commercially available isocyanate-based cross-linking agents include, for example, Tosoh Corp.'s Coronate (registered trademark) L (e.g., L-45E, etc.), HL, HX, 2030, 2031, and Mitsui Chemicals, Inc.'s Takenate (registered Trademark) D-102, D-110N, D-200, D-202, Duranate (registered trademark) 24A-100, TPA-100, TKA-100, P301-75E, E402-80B, E402 manufactured by Asahi Kasei Chemicals Co., Ltd. -90T, E405-80T, TSE-100, D-101, D-201, Sumidule (registered trademark) N-75, N-3200, N-3300 of Sumika Bayer Urethane Co., Ltd., Mitsui Chemicals Co., Ltd. Stabio (registered trademark) D-370N, D-376N, NISSO-PB (registered trademark) TP1001 manufactured by Nippon Soda Co., Ltd., and the like. Examples of carbodiimide-based cross-linking agents include Carbodilite (registered trademark) V-01, V-03, V-05, V-07 and V-09 manufactured by Nisshinbo Chemical Co., Ltd. Examples of oxazoline-based cross-linking agents include Epocross (registered trademark) WS-300, WS-500, WS-700, K-1000 series and K-2000 series manufactured by Nippon Shokubai Co., Ltd. Examples of epoxy-based cross-linking agents include TETRAD-C and TETRAD-X manufactured by Mitsubishi Gas Chemical Company, Inc., Adeka Resin EPU series and EPR series manufactured by ADEKA Corporation, and Celoxide series manufactured by Daicel Corporation. Examples of aziridine-based cross-linking agents include Chemitite (registered trademark) PZ-33 and DZ-22E manufactured by Nippon Shokubai Co., Ltd. For peroxides, for example, NOF Corporation Permil (registered trademark) ND, Perloyl (registered trademark) IB, NPP, IPP, SBP, TCP, OPP, 355, L, SA, Perocta (registered trademark) ND, O, Perhexyl (registered trademark) ND, PV, O, I, Perbutyl (registered trademark) ND, NHP, PV, O, L, I, A, Perhexa (registered trademark) 25O, MC, TMH, HC, C, 25Z , 22, Nyper (registered trademark) PMB, BMT, BW, BMT-K40, BMT-M, Pertetra (registered trademark) A and the like.

The amount of component (C) added to the pressure-sensitive adhesive composition is not particularly limited as long as it is an amount that allows the polymerization and crosslinking reaction with component (A) to proceed.

When the component (C) contains an isocyanate cross-linking agent (compound having an isocyanate group), the equivalent ratio of the total amount of isocyanate groups of the compound having an isocyanate group to the total amount of hydroxyl groups of the component (A) in the pressure-sensitive adhesive composition (NCO ( total) (mol)/OH (mol)) is preferably 0.2 or more and 10 or less. Further, the equivalent ratio is more preferably 0.4 or more and 10 or less, and further preferably 0.5 or more and 6 or less. Further, it is particularly preferable that the equivalent ratio is 1 or more and 4.5 or less. Within the above range, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer have a more appropriate adhesive strength, and the pressure-sensitive adhesive layer is less likely to come off. It is presumed that this is because the progress of the polymerization and cross-linking reaction with the component (A) becomes more appropriate.

Component (C) preferably contains a bifunctional isocyanate or a trifunctional or higher isocyanate.

(C) When the component contains an isocyanate cross-linking agent (compound having an isocyanate group), the equivalent ratio of the isocyanate group amount of the bifunctional isocyanate to the total amount of isocyanate groups of the compound having an isocyanate group in the pressure-sensitive adhesive composition (NCO ( (bifunctional) (mol)/NCO (total) (mol)) is preferably 0 or more and 1 or less. Moreover, since it is preferable that the compound in which the component (C) has an isocyanate group contains a bifunctional isocyanate, the equivalent ratio is more preferably more than 0 and 1 or less. Further, the equivalent ratio is more preferably greater than 0 and less than 1, and more preferably 0.25 or more and less than 1. Moreover, the equivalent ratio is particularly preferably 0.5 or more and 0.95 or less, and more particularly preferably 0.7 or more and 0.9 or less. Within the above range, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer are in a more appropriate range. In particular, when it is at least the above lower limit, the occurrence of detachment of the pressure-sensitive adhesive layer is further reduced. It is presumed that this is because the progress of the polymerization and cross-linking reaction with the component (A) becomes more appropriate. Moreover, when it is equal to or less than the above upper limit, it is possible to more reliably suppress bleeding out of additive components such as component (F) described later from the pressure-sensitive adhesive layer. It is presumed that this is because the crosslink density becomes higher and diffusion of these components in the pressure-sensitive adhesive layer becomes more difficult.

Component (C) preferably contains a trifunctional or higher isocyanate. According to the isocyanate, it is possible to more reliably suppress the bleed-out of additive components such as the component (F) to be described later from the pressure-sensitive adhesive layer, thereby further improving the substrate contamination resistance. It is presumed that this is because the crosslink density between the components (A) in the pressure-sensitive adhesive layer becomes higher, making it more difficult for these components to diffuse within the pressure-sensitive adhesive layer.

When component (C) contains a cross-linking agent other than an isocyanate-based cross-linking agent, the content of the cross-linking agent (the total amount if two or more are included) is 0.01 per 100 parts by mass of component (A). It is preferably at least 20 parts by mass. Moreover, the content of the cross-linking agent is more preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of component (A). Further, the content of the cross-linking agent is more preferably 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of component (A). Within the above range, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer have a more appropriate adhesive strength, and the pressure-sensitive adhesive layer is less likely to come off. It is presumed that this is because the progress of the polymerization and cross-linking reaction between the component (A) or the component (B) or its (co)polymer becomes more appropriate.

[(D) component: crosslinked particles]
The pressure-sensitive adhesive composition according to one aspect of the present invention contains component (D): crosslinked particles. As used herein, crosslinked particles refer to particles having a crosslinked structure as at least part of the structure constituting the particles. The component (D) has a function of forming unevenness on the surface of the pressure-sensitive adhesive layer. Here, the pressure-sensitive adhesive layer is formed with irregularities, thereby lowering the adhesive force. Therefore, the component (D) can contribute to making the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer in an appropriate range and further improving the pressure-sensitive adhesiveness. In addition, the component (D) can further reduce the adhesive force during rework and contribute to the improvement of reworkability. If the component (D) is not contained, the adhesive strength before light irradiation becomes excessive, resulting in poor adhesiveness. In addition, the adhesive strength after light irradiation becomes excessive and the reworkability becomes insufficient. Component (D) is not particularly limited, and known crosslinked particles can be used. Examples thereof include styrene crosslinked particles, (meth)acrylic crosslinked particles, fluorine-modified (meth)acrylic crosslinked particles, styrene-(meth)acrylic crosslinked particles, urethane crosslinked particles, and silicone crosslinked particles.

The styrenic crosslinked particles are crosslinked particles in which at least 50% by mass or more of the particles are composed of constitutional units composed of styrene monomers.

(Meth)acrylic crosslinked particles are crosslinked particles having at least 50% by mass or more of structural units derived from monomers ((meth)acrylate monomers) having (meth)acryloyloxy groups. Here, examples of (meth)acrylate monomers include combinations of known monofunctional (meth)acrylates and known polyfunctional (meth)acrylates. Preferred specific examples of the (meth)acrylic crosslinked particles include crosslinked particles mainly containing polymethyl methacrylate (PMMA).

The styrene-(meth)acrylic crosslinked particles are crosslinked particles having at least 50% by mass of structural units derived from styrene monomers or (meth)acrylate monomers.

The urethane-based crosslinked particles are crosslinked particles in which at least 50 mass % or more of the particles are composed of a polymer compound having urethane bonds or urea bonds. Here, examples of the polymer compound having a urethane bond or a urea bond include reaction products of known polyfunctional isocyanates and polyols, reaction products of known polyisocyanates and water, and the like.

The silicone-based crosslinked particles include, for example, those generally called silicone rubbers and those generally called silicone resins, which are mainly composed of crosslinked particles that are solid at room temperature. Preferred specific examples include silicone resin powders (polyorganosilsesquioxane cured products in which siloxane bonds have a three-dimensional network-like crosslinked structure) that are solid at room temperature.

In addition, examples of the crosslinked particles include crosslinked rubber particles other than those listed above.

Among these, (meth)acrylic crosslinked particles or silicone crosslinked particles are preferred, and silicone crosslinked particles are more preferred, from the viewpoints of both adhesiveness and reworkability, punching workability, wettability and transparency.

The component (D) may be core-shell particles having a crosslinked structure constituting the above crosslinked particles as a core portion or a shell portion. Moreover, the (D) component may be hollow particles.

The component (D) may be a coated particle obtained by further coating the surface of the particle containing the crosslinked structure constituting the crosslinked particle with a coating material. The coating material is not particularly limited, and known coating materials used for coating particles can be used. Examples include natural resins, synthetic resins, silicone resins, metals, and inorganic compounds.

The shape of component (D) is not particularly limited. For example, spherical, elliptical, amorphous, needle-like, plate-like, hollow, columnar, conical and the like can be mentioned. Among these, from the viewpoint of reducing adhesive strength, the shape is preferably spherical or elliptical, and more preferably spherical.

Although the average particle size of component (D) is not particularly limited, it is preferably 0.5 μm or more and 30 μm or less. In addition, the average particle size of component (D) is more preferably 0.5 μm or more and 25 μm or less, and further preferably 0.5 μm or more and 20 μm or less. When it is at least the above lower limit, the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer have better adhesiveness, and reworkability is further improved. It is presumed that this is because the size of the unevenness formed on the surface of the pressure-sensitive adhesive layer becomes larger, the adhesive strength is in a more appropriate range, and the adhesive strength after light irradiation is further reduced. Moreover, the wettability with respect to the base material of an adhesion layer improves more as it is below the said upper limit. It is presumed that this is because the unevenness of the surface of the pressure-sensitive adhesive layer becomes smaller, making it more difficult for air to enter the adhesive surface.

Although the color of component (D) is not particularly limited, it is preferably transparent from the viewpoint of ensuring the transparency of the pressure-sensitive adhesive film.

Component (D) may be a synthetic product or a commercial product. Commercially available products include, for example, Artpearl (registered trademark) GR series, SE series (e.g., SE-010T, SE-020T, etc.), G series, GS series, J series, MF series, MF series manufactured by Neagari Kogyo Co., Ltd. , BR series (cross-linked acrylic beads, transparent type), C series, P series, JB series, U series, CE series, AK series, HI series, MM series, FF series, TK series, C-TH series, RT , RW, RX, RY, RZ series, RU series, RV series, BP series (above, crosslinked urethane beads, transparent type), Shin-Etsu Chemical Co., Ltd. KMP-600, KMP-601, KMP-602, KMP-605 , X-52-7030 (or more, silicone composite powder), KMP-597, KMP-598, KMP-594, X-52-875 (or more, silicone rubber powder), KMP-590, KMP-701, X-52 -854, X-52-1621 (these are silicone resin powders), and the like.

A method for producing these crosslinked particles is not particularly limited, and a known method can be adopted. For example, there is a method of synthesizing a crosslinked polymer by a polymerization method such as suspension polymerization, sheet polymerization or emulsion polymerization, followed by washing, drying, classification, and the like. Another example is a method of preparing a polymer compound having a reactive functional group and crosslinking the polymer compound.

The crosslinked particles may be used alone or in combination of two or more.

The content of component (D) in the pressure-sensitive adhesive composition (the total amount when two or more are included) is 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of component (A). If it is less than the above lower limit, the adhesive strength becomes excessive, resulting in poor adhesiveness. Moreover, the adhesive strength of the adhesive layer becomes excessive during rework, and the reworkability of the adhesive layer and the adhesive film having the same becomes insufficient. On the other hand, when the above upper limit is exceeded, the adhesive strength becomes too small, resulting in poor adhesiveness. In addition, since the amount of the component (D) added becomes excessive, the component (D) tends to fall off, and the punching workability is deteriorated. Furthermore, the unevenness of the surface of the pressure-sensitive adhesive layer becomes excessive, the wettability of the pressure-sensitive adhesive layer to the adherend is reduced, light diffusion is likely to occur, and the transparency is also reduced. From this, from the viewpoint of adhesiveness, reworkability, punching workability, wettability and transparency, the content of component (D) is 0.05 parts by mass or more and 5 parts by mass per 100 parts by mass of component (A). Part or less is more preferable. The content of component (D) is more preferably 0.1 parts by mass or more and 1 part by mass or less per 100 parts by mass of component (A).

[(E) component: photoradical initiator]
The pressure-sensitive adhesive composition according to one aspect of the present invention contains component (E): a photoradical initiator. The component (E) has the function of generating radicals upon irradiation with light, and by promoting the photopolymerization and cross-linking of the component (B), it can contribute to the improvement of reworkability due to the reduction in adhesive force after light irradiation. . When the component (E) is not contained, the adhesive strength is not lowered by light irradiation, resulting in insufficient reworkability.

Component (E) is not particularly limited, and known components can be used. Examples thereof include acetophenone compounds, benzoin compounds, benzophenone compounds, thioxanthone compounds, anthraquinone compounds and acylphosphine oxide compounds. Other examples include 3,3',4,4'-tetra(t-butyloperoxycarbonyl)benzophenone and acrylated benzophenone.

Acetophenone compounds include, for example, 4-phenoxydichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methyl Propan-1-one, 1-hydroxycyclohexylphenyl ketone, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino -1-propanone, 2,2-dimethoxy-2-phenylacetophenone and the like.

Examples of benzoin compounds include benzoin compounds such as benzoin, benzoin methyl ether, benzoin isoethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

Examples of benzophenone compounds include benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3,3'-dimethyl-4-methoxybenzophenone, and the like. mentioned.

Thioxanthone compounds include, for example, thioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, and 2,4-diisopropylthioxanthone. are mentioned.

Examples of anthraquinone compounds include 4,4′-dimethylaminothioxanthone (also known as Minerazketone), 4,4′-diethylaminobenzophenone, α-acyloxime ester, benzyl, methylbenzoylformate, and 2-ethylanthraquinone. etc.

Examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

Acrylated benzophenones include, for example, 3,3',4,4'-tetra(t-butyloperoxycarbonyl)benzophenone, acrylated benzophenone, and the like.

Among these, acylphosphine oxide compounds are preferable, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide is more preferable, from the viewpoint that the reworkability of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the same can be further improved.

The component (E) may be a synthetic product or a commercial product. Commercially available products include, for example, Omnirad (registered trademark) 184, 369, 651, 819, 907, 1173 manufactured by IGM RESINS, TPO H, Ezacure (registered trademark) KIP150 manufactured by DKSH Japan Co., Ltd., TZT, and Nippon Kayaku. KAYACURE (registered trademark) BMS, DMBI, etc. manufactured by K.K.

A photoradical initiator may be used individually and may be used in combination of 2 or more type.

The content of component (E) in the pressure-sensitive adhesive composition (the total amount when two or more are included) is not particularly limited, but is 0.01 part by mass or more and 20 parts by mass per 100 parts by mass of component (A). The following are preferred. The content of component (E) is more preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 5 parts by mass or less per 100 parts by mass of component (A). It is even more preferable to have The content of component (E) is particularly preferably 1 part by mass or more and 2 parts by mass or less per 100 parts by mass of component (A). Within the above range, the reworkability of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer is further improved. It is presumed that this is because the photopolymerization and cross-linking reaction of the component (B) proceed further due to light irradiation during reworking.

[(F) component: antistatic agent]
The pressure-sensitive adhesive composition according to one aspect of the present invention preferably contains component (F): an antistatic agent. The component (F) has a function of improving electrical conductivity and can contribute to lowering the surface resistance of the pressure-sensitive adhesive layer. Therefore, it is possible to effectively suppress the generation of static electricity particularly when it is necessary to peel off (rework) due to a mistake in adhesion after lamination to an adherend such as a liquid crystal cell. As a result, it is possible to stably prevent dust from easily adhering to the surface of the polarizing plate, etc., from easily disturbing the alignment of the liquid crystal, and from easily causing electrostatic breakdown of peripheral circuit elements. can. From this, if the component (F) is not contained, the peeling electrification voltage becomes excessive.

Component (F) is not particularly limited, and any known component can be used. Examples thereof include ion conductive agents such as ionic liquids and bis(fluorosulfonyl)imide salts, and surfactants.

Examples of ionic liquids include phosphonium ions, pyridinium ions, pyrrolidinium ions, imidazolium ions, guanidinium ions, ammonium ions, isouronium ions, thiouronium ions, piperidinium ions, pyrazolium ions, sulfonium ions, fourth Cationic components such as class ammonium and quaternary phosphonium, and halogen ions, nitrate ions, sulfate ions, phosphate ions, perchlorate ions, thiocyanate ions, thiosulfate ions, sulfite ions, tetrafluoroborate ions, and hexafluorophosphate. and anionic components such as ions, formate ions, oxalate ions, acetate ions, trifluoroacetate ions, and alkylsulfonate ions.

Specific examples of ionic liquids include 1-allyl-3-methylimidazolium chloride, 1,3-dimethylimidazolium chloride, 1,3-dimethylimidazolium dimethylphosphate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium iodide, 1-ethyl-3-methanesulfonate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3 -methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium-p-toluenesulfonate, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-methyl- 1-propyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-methylpyrrolidinium bromide, 1-butyl-1-methylpiperidinium bromide, 1-ethylpyridinium chloride, 1-ethylpyridinium bromide , 1-butylpyridinium chloride, 1-butylpyridinium bromide, 1-butyl-3-methylpyridinium chloride, 1-ethyl-3-methylpyridinium ethylsulfate, 1-butyl-4-methylpyridinium chloride, 1-butyl-4- Methylpyridinium hexafluorophosphate, trimethylpropylammonium bis(trifluoromethanesulfonyl)imide, tributylmethylammonium bis(trifluoromethanesulfonyl)imide (also known as tri-n-butylmethylammonium bistrifluoromethanesulfonimide), tetrabutylammonium chloride , tetrabutylammonium bromide, cyclohexyltrimethylammonium bis(trifluoromethanesulfonyl)imide, tetrabutylphosphonium bromide and the like.

Surfactants include nonionic surfactants, ionic surfactants, and the like.

Examples of nonionic surfactants include polyethylene glycol alkyl ethers and polyoxyalkylene alkyl ethers.

Examples of ionic surfactants include cationic surfactants such as alkyltrimethylammonium halides having 8 to 22 carbon atoms and anionic surfactants such as alkyl sulfates.

Among these, ionic liquids are preferable, and tributylmethylammonium bis(trifluoromethanesulfonyl)imide is more preferable.

Component (F) may be a synthetic product or a commercial product. Examples of commercially available ionic liquids include 3M (trademark) ionic liquid type antistatic agent FC-4400 manufactured by 3M Japan Co., Ltd., and the like.

Antistatic agents may be used alone or in combination of two or more.

The content of component (F) in the pressure-sensitive adhesive composition (the total amount when two or more are included) is not particularly limited, but is 0.01 part by mass or more and 30 parts by mass per 100 parts by mass of component (A). The following are preferred. Further, the content of component (F) is more preferably 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of component (A), and 0.5 parts by mass or more and 15 parts by mass or less is More preferred. Further, the content of component (F) is more preferably 2 parts by mass or more and 5 parts by mass or less per 100 parts by mass of component (A). When it is at least the above lower limit, the peeling electrification voltage of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive film having the pressure-sensitive adhesive layer is further reduced. Moreover, the board|substrate contamination property of an adhesive layer and the adhesive film which has this as it is below the said upper limit improves more.

[(G) component: stabilizer]
The pressure-sensitive adhesive composition according to one aspect of the present invention may further contain component (G): a stabilizer as long as the effects of the present invention are not impaired. Component (G) stabilizes radicals generated by weak light (e.g., ultraviolet rays) such as illumination, and progresses the photocuring reaction of the adhesive composition, its cured product, and the adhesive layer before light irradiation treatment. has the function of suppressing From this, by adding the (G) component, the adhesive composition, its cured product, and the adhesive layer can be stored in an environment where weak light (e.g., ultraviolet rays) is irradiated, for example, under LED lighting. and the storability can be improved. On the other hand, since a large amount of light is irradiated at the time of light irradiation, a large amount of radicals are generated at the time of light irradiation, and the stabilizing effect of the component (G) cannot keep up. As a result, the photocuring reaction during light irradiation proceeds even in the presence of the component (G), and the adhesive strength of the adhesive layer can be reduced. In the specification of the present application, the stabilizer means either an antioxidant, a light stabilizer, a polymerization inhibitor or an ultraviolet absorber.

Component (G) is not particularly limited as long as it is an antioxidant, a light stabilizer, a polymerization inhibitor or an ultraviolet absorber, and known ones can be used. Among these, antioxidants and light stabilizers are preferred.

Examples of antioxidants include hindered phenol-based antioxidants and phosphorus-based antioxidants.

The hindered phenol-based antioxidant is not particularly limited, and examples thereof include compounds having a sterically hindered hydroxyphenyl group. Here, the sterically hindered hydroxyphenyl group is not particularly limited as long as it is a bulky substituted hydroxyphenyl group. Examples include, but are not limited to, those having substituted or unsubstituted alkyl groups at the 2- and 6-positions of the hydroxyphenyl group. Examples of hindered phenol antioxidants include triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], pentaerythritol-tetrakis[3-(3,5 -di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, thiodiethylene-bis[3-(3,5-di -t-butyl-4-hydroxyphenyl)propionate], benzenepropionic acid, 3,5-bis(1,1-dimethyl)-4-hydroxy-C7-C9 branched alkyl ester, 4,6-bis(dodecylthiomethyl )-o-cresol, 3,3′,3″,5,5′,5″-hexa-t-butyl-α,α′,α″-(mesitylene-2,4,6-triyl)tri-p - cresol, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-t-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 1,6-hexanediol-bis[3-(3, 5-di-t-butyl-4-hydroxyphenyl)propionate], ethylenebis(oxyethylene)bis[3-(5-t-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene-bis[3 -(3,5-di-t-butyl-4-hydroxyphenyl)propionate], isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 1,3,5-trimethyl- 2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methyl phenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, N,N'-hexane-1,6-diylbis[3-(3, 5-di-t-butyl-4-hydroxyphenyl)propionamide], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), N,N'- Bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine, diethyl[(3,5-bis(1,1-dimethylethyl)-4-hydrazine doloxyphenyl)methyl]phosphate, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 3,3′,3″,5,5′,5″-hexa-t -butyl-a,a',a''-(mesitylene-2,4,6-triyl)tri-p-cresol, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butyl Phenyl)butane, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethyl)isocyanuric acid, 1,3,5-tris(4-sec-butyl-3-hydroxy-2 ,6-dimethyl)isocyanuric acid, 1,3,5-tris(4-neopentyl-3-hydroxy-2,6-dimethyl)isocyanuric acid, 2,2′-methylenebis(4-methyl-6-t-butylphenol) , 4,4′-butylidenebis(4-methyl-6-t-butylphenol), tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, tris-(3,5-di- t-butyl-4-hydroxybenzyl)-isocyanurate, polycondensate of p-chloromethylstyrene and p-cresol, polycondensate of p-chloromethylstyrene and divinylbenzene, polycondensate of p-cresol and divinylbenzene Examples include isobutylene reactants.

Examples of phosphorus antioxidants include triphenylphosphite, tris(2,4-di-t-butylphenyl)phosphite, diphenyloctylphosphite, diphenylisodecylphosphite, phenyldiisodecylphosphite, tetrakis(2 ,4-di-t-butylphenyl)-4,4'-biphenylene phosphite, trisnonylphenyl phosphite, bis(2,4-di-t-butylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite Phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,4 -dicumylphenyl)pentaerythritol-diphosphite, tetrakis(2,4-di-t-butylphenyl)(1,1-biphenyl)-4,4'-diylbisphosphonite, di-t-butyl-m-cresyl - phosphonite, distearyl pentaerythritol diphosphite, di(2,4-di-t-butylphenyl)-pentaerythryl diphosphite, di(2,6-di-t-butyl-4-methylphenyl)- Pentaerythryl diphosphite, 4,4′-butylidene-bis(3-methyl-6-t-butylphenyl-ditridecyl)phosphite, cyclic neopentanetetrayl (octadecylphosphite), diisodecylpentaerythritol diphosphite , 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite, bis(tridecyl)pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, hydrogenated bisphenol A pentaerythritol phosphite phytopolymer, hydrogenated bisphenol A phosphite polymer, tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite, tetra(tridecyl)-4,4'-isopropylidene diphenyl diphosphite, tetraphenyldipropylene glycol diphosphite, etc. mentioned.

Light stabilizers include, for example, hindered amine light stabilizers (HALS).

Hindered amine light stabilizers (HALS) are not particularly limited, but include, for example, compounds having a sterically hindered piperidyl group. Here, the sterically hindered piperidyl group is not particularly limited as long as it is a bulky substituted piperidyl group. For example, a piperidyl group having 1 or more and 2 or less alkyl groups at each of the 2- and 6-positions may be mentioned, but it is not limited thereto. Examples of hindered amine light stabilizers (HALS) include bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, methyl (1,2,2,6,6-pentamethyl-4-piperidinyl) ) sebacate, 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1 , 3,5-triazine, decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) ester, bis(1,2,2,6,6-pentamethyl-4 -piperidinyl)-2-butyl-2-(4-hydroxy-3,5-di-t-butylbenzyl)propanedioate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 4 -(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2 , 2,6,6-pentamethylpiperidine, 4-(meth)acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4-(meth)acryloylamino-2,2,6 ,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl- 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine , 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine and the like.

Examples of polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, benzoquinone, pt-butylcatechol, and 2,6-dibutyl-4-methylphenol.

Examples of UV absorbers include benzophenone-based UV absorbers such as 2,4-dihydroxy-benzophenone and 2-hydroxy-4-methoxy-benzophenone. In addition, for example, 2-(2'-hydroxy-5-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole-based UV-absorbing benzotriazole agents. Also, for example, 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-ethoxyphenyl)- Examples thereof include triazine-based ultraviolet absorbers such as 1,3,5-triazine.

Among these, antioxidants or light stabilizers are preferred, and hindered phenol antioxidants or hindered amine light stabilizers (HALS) are more preferred. And, pentaerythritol-tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, methyl ( More preferred is 1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate.

The component (G) may be a synthetic product or a commercial product. Commercially available hindered phenolic antioxidants include, for example, BASF Japan Ltd. Irganox (registered trademark) 1010, 1010FF, 1035, 1035FF (W&C), 1076, 1076FD, 1098, 1135, 1330, 1530L, 1726, 245, 245FF, 259, 3114, 565 and the like. Hindered amine light stabilizers (HALS) include, for example, BASF Japan Ltd. Tinuvin (registered trademark) 111 FDL, 123, 144, 292, 5100, 123-DW, 622 SF, PA 144, 765, 770DE, XT 55 FB, 783 FDL, 791 FB, Chimassorb (registered trademark) 2020 FDL, 944 FDL, 944 LD and the like.

Antioxidants, light stabilizers, polymerization inhibitors or UV absorbers may be used alone or in combination of two or more. When two or more types are used, two or more of the same system may be combined, or one or more of different systems may be combined.

Commercial products related to combinations of different systems include, for example, a blend of an ultraviolet absorber and a hindered amine light stabilizer (HALS), for example, Tinuvin (registered trademark) 5050, 5060, 5151, 5333 manufactured by BASF Japan Ltd. - DW and the like.

The content of component (G) in the pressure-sensitive adhesive composition (the total amount when two or more are included) is not particularly limited. However, in order to obtain the effect of the above component (G) better, the content of component (G) should not exceed 5 parts by mass with respect to 100 parts by mass of component (A), that is, (G ) is preferably 5 parts by mass or less. This is because when the content of component (G) exceeds 5 parts by mass, the amount of radicals stabilized by component (G) increases, and the progress of the photocuring reaction during light irradiation may be suppressed. . The content of component (G) is more preferably 3 parts by mass or less, more preferably 0.5 parts by mass or less per 100 parts by mass of component (A). When it is within the above range, it does not affect the effect of reducing the adhesive force after the light irradiation treatment of the adhesive layer. In addition, the pressure-sensitive adhesive composition contains component (G), that is, the content of component (G) in the pressure-sensitive adhesive composition (the total amount when two or more are included) is 100 parts by mass of component (A) It is preferably in excess of 0 parts by mass. This is because radicals generated in an environment where the pressure-sensitive adhesive layer is irradiated with weak light (for example, ultraviolet rays), for example, under LED lighting can be stabilized. The content of component (G) is more preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more per 100 parts by mass of component (A). Within the above range, the storability of the pressure-sensitive adhesive layer is further improved under an environment where weak light (for example, ultraviolet rays) is irradiated, for example, under LED lighting. From this, when the pressure-sensitive adhesive composition contains the component (G), an example of a preferable range of its content is more than 0 parts by mass and 5 parts by mass or less with respect to 100 parts by mass of the component (A). .

[Other ingredients]
The pressure-sensitive adhesive composition according to one aspect of the present invention may further contain known additives as long as the effects of the present invention are not impaired. Additives are not particularly limited. For example, curing accelerators, lithium salts, fillers, softeners, anti-aging agents, tackifying resins, leveling agents, defoaming agents, plasticizers, dyes, pigments, treating agents, fluorescent brighteners, dispersants, lubricants, etc. is mentioned.

[Method for preparing adhesive composition]
The preparation method (manufacturing method) of the pressure-sensitive adhesive composition according to one aspect of the present invention is not particularly limited, and known methods can be used. A pressure-sensitive adhesive composition according to one aspect of the present invention can usually be obtained by mixing the components described above. The mixing method is also not particularly limited. Examples of the mixing method include a method of mixing the components together, a method of sequentially adding and mixing each component, and a method of mixing a plurality of arbitrary components and then mixing the remaining components. After mixing, it is preferable to stir so as to form a uniform mixture. Stirring may be performed with a stirrer or the like in a place shielded from light of a specific wavelength, if necessary, until the mixture becomes uniform. In addition, if necessary, the mixture may be heated and stirred with a stirrer or the like until uniform. Here, the stirring time is not particularly limited, but may be, for example, 10 minutes or more and 5 hours or less. Moreover, when heating, the temperature after heating is not particularly limited, but for example, 30° C. or higher and 40° C. or lower can be mentioned.

Another aspect of the present invention relates to an adhesive composition solution containing the above-described adhesive composition and a solvent. In this specification, a solution or dispersion containing the above adhesive composition and a solvent is referred to as "adhesive composition solution". Here, the pressure-sensitive adhesive composition solution may be used for improving uniformity of the pressure-sensitive adhesive composition by mixing, or may be used as a coating liquid for forming the pressure-sensitive adhesive layer described later.

It is preferable to use a solvent (solvent, dispersion medium) when preparing the pressure-sensitive adhesive composition or when preparing the coating liquid. Although the solvent is not particularly limited, it is preferably an organic solvent. There are no particular restrictions on the organic solvent. Examples include toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, hexane, acetone, cyclohexanone, 3-pentanone, acetonitrile, propionitrile, isobutyronitrile, valeronitrile, dimethylsulfoxide and dimethylformamide. Among these, methyl ethyl ketone and ethyl acetate are preferred. An organic solvent may be used individually and may be used in combination of 2 or more type.

Although the concentration of the adhesive composition in the adhesive composition solution is not particularly limited, it is preferably 20% by mass or more and 99% by mass or less with respect to the total mass of the adhesive composition solution. Moreover, the concentration of the adhesive composition is more preferably 30% by mass or more and 95% by mass or less with respect to the total mass of the adhesive composition solution. Within the above range, the drying property of the pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition is further improved, and the coatability when used as a coating liquid is further improved.

In addition, it is preferable to perform preparation of an adhesive composition and an adhesive composition solution, and these storage in a light-shielding environment. For example, when the adhesive strength of the pressure-sensitive adhesive composition decreases due to ultraviolet irradiation, it is preferable to prepare and store the composition in an ultraviolet-shielding environment, for example, in a yellow room. This is because the progress of the photocuring reaction of the pressure-sensitive adhesive composition can be further suppressed, and the effect of reducing the adhesive strength of the pressure-sensitive adhesive layer after light irradiation can be further improved.

<Adhesive layer and its manufacturing method>
Another aspect of the present invention relates to a cured product of the pressure-sensitive adhesive composition. Yet another aspect of the present invention relates to a pressure-sensitive adhesive layer composed of a cured product of the above pressure-sensitive adhesive composition. Here, as described above, the adhesive composition is preferably a thermosetting adhesive composition, and the cured product is preferably a thermoset product.

In addition, as described above, the thermoset is a cured product formed by the progress of a cross-linking reaction by heat. A thermoset does not necessarily require heating, and includes a cured product cured at room temperature (20° C. or higher and 25° C. or lower).

The adhesive strength of the cured product according to one aspect of the present invention is reduced by light irradiation. Therefore, the pressure-sensitive adhesive layer according to one embodiment of the present invention exhibits extremely good adhesiveness in an adhesive state, and exhibits remarkably excellent reworkability by performing light irradiation treatment. Here, the ratio of the adhesive force after light irradiation to the adhesive force before light irradiation treatment of the adhesive film according to one embodiment of the present invention is in the same range as the ratio of the adhesive force after light irradiation treatment of the adhesive film described later. is preferably

From the viewpoint of achieving both adhesiveness and reworkability, the adhesive strength of the adhesive layer according to one embodiment of the present invention is preferably in the same range as the adhesive strength of the adhesive film described later. The adhesive strength can be measured using a tensile tester, and the details of the measuring method are described in Examples.

From the viewpoint of reworkability, the adhesive strength after light irradiation treatment of the pressure-sensitive adhesive layer according to one embodiment of the present invention is preferably in the same range as the adhesive strength after light irradiation treatment of the adhesive film described below. The adhesive strength after light irradiation treatment can be measured using a tensile tester, and the details of the measuring method will be described in Examples. The preferred irradiation light and the preferred range of irradiation energy in the light irradiation treatment of the pressure-sensitive adhesive layer are also the same as the preferred conditions for the light irradiation treatment of the pressure-sensitive adhesive film, which will be described later.

A method for forming the pressure-sensitive adhesive layer is not particularly limited, and a known method can be used. A preferred method is a method in which the pressure-sensitive adhesive composition itself or a solution of the pressure-sensitive adhesive composition is applied onto a support, and the formed coating film is subjected to heat drying treatment or heat treatment as necessary.

Moreover, the coating thickness of the adhesive composition (the thickness after drying, the thickness of the adhesive layer) is not particularly limited. The thickness may be selected according to the purpose of the adhesive layer and, when used as an adhesive film, the type of the substrate. The thickness is preferably 1 μm or more and 500 μm or less. Further, the thickness is more preferably 10 μm or more and 300 μm or less, and further preferably 20 μm or more and 200 μm or less.

A coating method is not particularly limited, and a known method can be used. For example, natural coater, knife belt coater, floating knife, knife over roll, knife on blanket, spray, dip, kiss roll, squeeze roll, reverse roll, air blade, curtain flow coater, doctor blade, wire bar, die coater, comma coater. , a method using an apparatus such as a Baker applicator and a gravure coater.

When the pressure-sensitive adhesive composition itself is used for forming the pressure-sensitive adhesive layer, the heat treatment temperature of the pressure-sensitive adhesive composition is not particularly limited. As long as it is a thermosetting pressure-sensitive adhesive composition, the temperature is not particularly limited as long as the cross-linking reaction can sufficiently proceed. The heat treatment temperature is preferably 20° C. or higher and 150° C. or lower, and more preferably 40° C. or higher and 150° C. or lower. Further, the heat treatment temperature is more preferably 50° C. or higher and 140° C. or lower, and particularly preferably 80° C. or higher and 130° C. or lower. Moreover, in this case, the heat treatment time of the pressure-sensitive adhesive composition is not particularly limited. As long as it is a thermosetting pressure-sensitive adhesive composition, there is no particular limitation as long as the time allows the cross-linking reaction to proceed sufficiently. The heat treatment time is preferably from 5 seconds to 20 minutes, more preferably from 30 seconds to 10 minutes, and even more preferably from 1 minute to 7 minutes. In the case of a thermosetting pressure-sensitive adhesive composition, by setting the heating conditions within the above range, the cross-linking reaction of the pressure-sensitive adhesive composition can proceed more appropriately, and a pressure-sensitive adhesive layer having better adhesive strength can be obtained. be able to.

Moreover, when using an adhesive composition solution for formation of an adhesive layer, the heat-drying process temperature of an adhesive composition solution is not specifically restricted. As long as it is a thermosetting pressure-sensitive adhesive composition, the temperature is not particularly limited as long as the cross-linking reaction can sufficiently proceed. The heat drying treatment temperature is preferably 40° C. or higher and 150° C. or lower, more preferably 50° C. or higher and 140° C. or lower, and even more preferably 80° C. or higher and 130° C. or lower. Moreover, in this case, the heat drying treatment time is not particularly limited. As long as it is a thermosetting pressure-sensitive adhesive composition, there is no particular limitation as long as the time allows the cross-linking reaction to proceed sufficiently. The heating and drying treatment time is preferably 5 seconds or more and 20 minutes or less, more preferably 30 seconds or more and 10 minutes or less, and even more preferably 1 minute or more and 7 minutes or less. The solvent can be sufficiently removed by setting the heating and drying conditions within the above range. Moreover, if it is a thermosetting pressure-sensitive adhesive composition, the cross-linking reaction of the pressure-sensitive adhesive composition can proceed more appropriately, and a pressure-sensitive adhesive layer having better adhesive strength can be obtained.

Moreover, when forming the pressure-sensitive adhesive layer, it is preferable to further perform an aging treatment after coating and heat treatment or heat drying treatment. By performing the aging treatment, the crosslinking reaction of the pressure-sensitive adhesive composition can proceed more appropriately, and a pressure-sensitive adhesive layer having better adhesive strength can be obtained. Aging treatment conditions are not particularly limited, and known conditions in a method for producing an adhesive layer can be employed. The aging treatment temperature is preferably 10° C. or higher and 40° C. or lower, more preferably room temperature (20° C. or higher and 25° C. or lower). The relative humidity of the aging treatment is preferably 10% RH or more and 80% RH or less, and preferably 40% RH or more and 50% RH or less. The aging treatment time is preferably 1 day or more and 7 days or less. Accordingly, one example of preferable aging treatment conditions is to perform the aging treatment for 7 days in an environment of 23° C. and 50% RH. By setting the aging treatment conditions within the above range, the cross-linking reaction of the pressure-sensitive adhesive composition can proceed more appropriately, and a pressure-sensitive adhesive layer having better adhesive strength can be obtained.

The aging treatment is preferably performed in a state in which the support, the coating film after heat drying and heating, and the release film described below are laminated in this order.

Formation and storage of the pressure-sensitive adhesive layer are preferably carried out in a light-shielding environment. For example, when the adhesive strength of the pressure-sensitive adhesive composition and its cured product is reduced by ultraviolet irradiation, it is preferable to form and store the composition under an ultraviolet-shielding environment, for example, in a yellow room. This is because the progress of the photocuring reaction of the adhesive composition and its cured product can be further suppressed, and the effect of reducing the adhesive strength of the adhesive layer after light irradiation can be further improved.

<Adhesive film>
Another aspect of the present invention relates to a pressure-sensitive adhesive film including a substrate and a pressure-sensitive adhesive layer composed of a cured product of the pressure-sensitive adhesive composition (that is, the pressure-sensitive adhesive layer described above). That is, it can be said that the form is a pressure-sensitive adhesive film including a base material and a pressure-sensitive adhesive layer composed of a cured product of the pressure-sensitive adhesive composition. Here, as described above, the adhesive composition is preferably a thermosetting adhesive composition, and the cured product is preferably a thermoset product. The details of the adhesive layer are as described above.

The adhesive film is preferably a surface protection film. A surface protective film is a film that is laminated on the surface of members such as various optical components and various substrates for the purpose of surface protection during the manufacturing process of the product or until the final product is used.

The pressure-sensitive adhesive layer is arranged on at least one surface of the substrate directly or via another member. Among these, the pressure-sensitive adhesive layer is preferably arranged only on one surface of the substrate directly or via another member.

The substrate is not particularly limited, and known substrates can be used. Among these, a resin film is preferable. This is because the resin film is excellent in properties required for use as an adhesive film, particularly as a surface protection film, such as high surface protection properties, good handleability, and high transparency. The resin constituting the resin film is not particularly limited, and known resins can be used. Here, "a film containing a resin as a main component" means that the content of the resin of interest is 50% by mass or more with respect to the total mass of the resin film. Here, the content of the resin of interest is preferably 70% by mass or more, more preferably 80% by mass or more, relative to the total mass of the resin film. Moreover, the content of the resin of interest is more preferably 90% by mass or more, and particularly preferably 95% by mass or more (upper limit of 100% by mass) relative to the total mass of the resin film.

Examples of the resin constituting the resin film include films mainly composed of resins such as polyester-based resins, cellulose-based resins, polycarbonate-based resins, acrylic-based resins, styrene-based resins, olefin-based resins, and polyamide-based resins. be done. Examples of polyester-based resins include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate. Cellulose-based resins include, for example, diacetyl cellulose and triacetyl cellulose. Examples of acrylic resins include polymethyl (meth)acrylate. Examples of styrene-based resins include polystyrene and acrylonitrile-styrene copolymers. Examples of olefinic resins include polyethylene, polypropylene, polyolefins having a cyclic structure (preferably norbornene structure), and ethylene-propylene copolymers. Examples of polyamide-based resins include nylon 6, nylon 6,6, and aromatic polyamides. Among these, a film containing a polyester resin as a main component (polyester resin film) is preferable. A film (polyethylene terephthalate film, PET film) containing polyethylene terephthalate as a main component is more preferable. The resin material constituting the resin film may be used alone or in combination of two or more.

Although the film thickness of the base material is not particularly limited, it is preferably 10 μm or more and 500 μm or less. Further, the film thickness of the substrate is more preferably 20 μm or more and 200 μm or less, and further preferably 40 μm or more and 100 μm or less.

The substrate may be surface-treated. The surface treatment is not particularly limited, and known methods can be used.

The pressure-sensitive adhesive film may further have other members in addition to the substrate and the pressure-sensitive adhesive layer. The other member is not particularly limited, and includes various known members possessed by the pressure-sensitive adhesive layer. For example, an intermediate layer provided between the base material and the pressure-sensitive adhesive layer, and a release film adhered to the surface of the pressure-sensitive adhesive layer on the side opposite to the base material can be used. Among these, a release film is preferred. The intermediate layer and release film are not particularly limited, and known ones used in the adhesive film field can be used.

Examples of the release film include a polyethylene terephthalate film whose surface is treated with a silicone release agent. Examples of commercially available release films include Diafoil (registered trademark) MRF38 manufactured by Mitsubishi Plastics, Inc., and the like.

A method for producing an adhesive film according to one aspect of the present invention is not particularly limited, and a known method can be used. The above adhesive composition itself or the above adhesive composition solution is coated on a substrate, and the formed coating film is optionally subjected to heat drying treatment or heat treatment. preferable.

Accordingly, a preferred example of the pressure-sensitive adhesive film according to one aspect of the present invention has a resin film and a pressure-sensitive adhesive layer composed of a cured product of the pressure-sensitive adhesive composition arranged on one side of the resin film. , is a surface protection film.

In addition, it is preferable to perform manufacture and storage of an adhesive film in a light-shielding environment. For example, when the adhesive strength of the pressure-sensitive adhesive composition and its cured product is reduced by ultraviolet irradiation, it is preferable to carry out production and storage under an ultraviolet-shielding environment, for example, in a yellow room. This is because the progress of the photocuring reaction of the adhesive composition and its cured product can be further suppressed, and the effect of reducing the adhesive strength of the adhesive layer after light irradiation can be further improved.

Moreover, the adhesive force of the adhesive layer of the adhesive film which concerns on one form of this invention falls by light irradiation treatment. Therefore, the adhesive film according to one embodiment of the present invention exhibits extremely good adhesiveness in an adhesive state, and exhibits remarkably excellent reworkability by performing light irradiation treatment during rework. The ratio of the adhesive strength after light irradiation treatment to the adhesive strength before light irradiation treatment of the adhesive film according to one embodiment of the present invention is not particularly limited as long as it is less than 100%. From the viewpoint of reworkability, the smaller the ratio, the better. When the adherend is glass, the proportion of the pressure-sensitive adhesive film according to one aspect of the present invention, particularly the surface protection film, is preferably 0% or more and 75% or less. Moreover, the ratio is more preferably 0% or more and 55% or less, and further preferably 0% or more and 35% or less. Moreover, it is more preferable that the ratio is 0% or more and 30% or less. Further, it is particularly preferable that the ratio is 0% or more and 20% or less.

The adhesive strength of the adhesive film according to one aspect of the present invention before light irradiation treatment is not particularly limited. When the adherend is glass, the adhesive film according to one aspect of the present invention, particularly the surface protection film, preferably has an adhesive strength of 5 g/25 mm or more and 20 g/25 mm or less. Further, the adhesive strength is more preferably 6 g/25 mm or more and 15 g/25 mm or less, and further preferably 8 g/25 mm or more and 13 g/25 mm or less. Within the above range, both the adhesiveness and reworkability of the adhesive film are achieved at a higher level. The adhesive strength can be measured using a tensile tester, and the details of the measuring method are described in Examples.

The adhesive strength of the adhesive film according to one aspect of the present invention after light irradiation treatment is not particularly limited as long as it is a value smaller than that before light irradiation treatment. From the viewpoint of reworkability, the adhesive strength is preferably as small as possible. When the adherend is glass, the adhesive strength of the adhesive film according to one aspect of the present invention, particularly the surface protection film, is particularly limited as long as it is a lower value than the adhesive strength of the adhesive film before light irradiation. Although not preferred, it is preferably less than 5 g/25 mm. Further, the adhesive strength is more preferably 3 g/25 mm or less, further preferably 2.5 g/25 mm or less (lower limit 0 g/25 mm). The adhesive strength after light irradiation treatment can be measured using a tensile tester, and the details of the measuring method will be described in Examples.

The irradiation light in the light irradiation treatment is not particularly limited as long as the photopolymerization and cross-linking of the component (B) by the component (E) can be progressed. The irradiation light can be appropriately selected depending on the types of components (E) and (B). Among these, from the viewpoint of controllability, ease of handling, and cost, ultraviolet rays are preferable, and ultraviolet rays having a wavelength of 200 nm or more and 400 nm or less are more preferable.

A light irradiation device is not particularly limited, and a known device can be used. In the case of ultraviolet irradiation treatment, light sources such as metal halide lamps, high-pressure mercury lamps, UV-LED lamps, low-pressure mercury lamps, xenon arc lamps, carbon arc lamps, excimer lamps, and UV light lasers are examples.

The light irradiation energy amount is not particularly limited. In the case of ultraviolet irradiation treatment, the amount of ultraviolet irradiation energy is preferably 50 mJ/cm ² or more and 5000 mJ/cm ² or less. In this case, the ultraviolet irradiation energy amount is more preferably 100 mJ/cm ² or more and 3000 mJ/cm ² or less, and further preferably 300 mJ/cm ² or more and 1500 mJ/cm ² or less.

In the adhesive film according to one embodiment of the present invention, the adhesive strength before UV irradiation after the LED stability test (adhesive strength after LED stability test) is It is preferable not to change from adhesive strength. Here, in the LED stability test, the adhesive film manufactured and stored in an ultraviolet shielding environment is left for 15 days (360 hours) in a test environment of 23 ° C. × 50% RH under LED lighting (500 Lux). conduct. The adhesive strength ratio is obtained by dividing the adhesive strength value after the LED stability test by the adhesive strength value before ultraviolet irradiation when manufactured and stored in an ultraviolet shielding environment. When the adherend is glass, the pressure-sensitive adhesive film according to one aspect of the present invention, particularly the surface protection film, has an adhesion ratio (glass adhesion ratio), which is not particularly limited, but is 0.8 or more and 1.2 or less. is preferred.

In the adhesive film according to one aspect of the present invention, the adhesive strength after UV irradiation after the LED stability test (adhesive strength after UV treatment after the LED stability test) is measured after manufacturing and storing in an ultraviolet shielding environment. It is preferable that the adhesive strength does not change from that after irradiation with ultraviolet rays when irradiation treatment is performed. Here, in the LED stability test, the adhesive film manufactured and stored in an ultraviolet shielding environment is left for 15 days (360 hours) in a test environment of 23 ° C. × 50% RH under LED lighting (500 Lux). conduct. The value obtained by dividing the adhesion value after UV treatment after the LED stability test by the adhesion value after UV irradiation when UV irradiation treatment is performed after manufacturing and storing in an ultraviolet shielding environment, This will be used as the adhesive force ratio later. When the adherend is glass, the adhesive strength ratio after ultraviolet irradiation (glass adhesive strength ratio after ultraviolet irradiation) of the pressure-sensitive adhesive film according to one embodiment of the present invention, particularly the surface protection film, is not particularly limited. It is preferably 2 or less (lower limit 0).

The peeling electrostatic voltage of the pressure-sensitive adhesive film according to one aspect of the present invention is not particularly limited. The absolute value of the peeling withstand voltage is preferably as small as possible from the viewpoint that the pressure-sensitive adhesive film after peeling is not charged and is excellent in workability. The absolute value of the peeling electrostatic voltage of the pressure-sensitive adhesive film according to one aspect of the present invention, particularly the surface protection film, is preferably 10 kV or less. Moreover, the absolute value is more preferably 2 kV or less, and further preferably 0.5 kV or less. Further, the absolute value is more preferably 0.3 kV or less, and particularly preferably 0.2 kV or less (lower limit 0 kV). The peeling electrification voltage can be measured using a potential measuring device, and the details of the measuring method will be described in Examples.

The pressure-sensitive adhesive film according to one aspect of the present invention preferably has high transparency. Transparency can be evaluated mainly by transmittance and HAZE.

The transmittance of the adhesive film according to one aspect of the present invention is not particularly limited. It is preferable that the transmittance is as close to 100% as possible from the viewpoint that the inspection can be performed with higher accuracy while the pressure-sensitive adhesive film is stuck. The transmittance of the pressure-sensitive adhesive film according to one aspect of the present invention, particularly the surface protection film, is preferably 85% or more, more preferably 90% or more (upper limit of 100%). The transmittance can be measured using a haze meter, and the details of the measuring method are described in Examples.

HAZE of the adhesive film according to one aspect of the present invention is not particularly limited. HAZE is preferably as small as possible from the viewpoint that inspection can be performed with higher accuracy while the pressure-sensitive adhesive film is being bonded. The HAZE of the pressure-sensitive adhesive film according to one aspect of the present invention, particularly the surface protective film, is preferably 3% or less, more preferably 2% or less (lower limit of 0%). HAZE can be measured using a haze meter, and the details of the measuring method are described in Examples.

The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

A thermosetting adhesive composition was prepared according to the following procedure. Hereinafter, the preparation and storage of the thermosetting pressure-sensitive adhesive composition, and the production and evaluation of the surface protective film were all carried out in a yellow room that shields ultraviolet rays. That is, the thermosetting pressure-sensitive adhesive composition and the surface protective film were present in an ultraviolet shielding environment from preparation to completion of the evaluation, except when they were intentionally exposed to ultraviolet rays in the following evaluation.

<Preparation of adhesive composition>
[Preparation of thermosetting adhesive composition 1]
(A) Component Negami Kogyo Co., Ltd. Product name: 35 parts by mass of TMPTA as component (B) for 100 parts by mass of Artresin (registered trademark) UN5500P, and Asahi Kasei Corporation as component (C) Product name: Duranate (registered trademark) D101 5.3 parts by mass, and Asahi Kasei Corporation trade name: Duranate (registered trademark) E402-80B 3.9 parts by mass, Negami Kogyo Co., Ltd. SE-010T 1 part by mass as component (D) , IGM Resins product name as component (E): 1 part by mass of Omnirad (registered trademark) TPO H, 3M Japan Co., Ltd. product name as component (F): 2 masses of 3M (trademark) ionic liquid antistatic agent FC4400 A thermosetting adhesive composition 1 was prepared by mixing parts. Then, ethyl acetate was added so that the concentration of the thermosetting adhesive composition (concentration of the total amount of each component) was 50% by mass to prepare an adhesive composition solution 1.

[Preparation of thermosetting adhesive compositions 2 to 23]
In the preparation of the thermosetting adhesive composition 1, each thermosetting adhesive composition was prepared by changing the type and amount of each component as shown in Tables 1 to 3 below. Then, in the same manner as in the preparation of the thermosetting adhesive composition 1, each adhesive composition solution was prepared.

Tables 1 to 3 below show the formulation of each thermosetting pressure-sensitive adhesive composition. In the table, the NCO group represents an isocyanate group. The details of each component are shown below in Tables 1 to 3 below. In addition, components not listed in Table 3 were not used in the preparation of each thermosetting pressure-sensitive adhesive composition listed in Table 3.

[(A) component: urethane prepolymer having two or more hydroxyl groups]
A1: Artresin (registered trademark) UN5500P (a urethane prepolymer having a hydroxyl group at both ends, an acryloyloxy group in a side chain, and a polyether skeleton), manufactured by Negami Kogyo Co., Ltd.;
[(B) component: polyfunctional (meth)acrylate]
B1: TMPTA (trimethylolpropane triacrylate, hydroxyl value 0 mgKOH/g).

[(C) component: cross-linking agent]
C1: Duranate (registered trademark) D101 (bifunctional isocyanate (HDI)), manufactured by Asahi Kasei Corporation;
C2: Duranate (registered trademark) E402-80B (elastic trifunctional isocyanate), manufactured by Asahi Kasei Corporation;
C3: Perloyl (registered trademark) TCP (bis(4-t-butylcyclohexyl) peroxydicarbonate) manufactured by NOF Corporation.

[(D) component: crosslinked particles]
D1: SE-010T ((meth)acrylic crosslinked particles, acrylic crosslinked beads, average particle size 10 μm), manufactured by Negami Kogyo Co., Ltd.;
D2: SE-020T ((meth)acrylic crosslinked particles, acrylic crosslinked beads, average particle size 19 μm), manufactured by Negami Kogyo Co., Ltd.;
D3: X-52-854 (silicone-based crosslinked particles, silicone resin powder, average particle size 0.7 μm), manufactured by Shin-Etsu Chemical Co., Ltd.

[(E) component: photoradical initiator]
E1: Omnirad® TPO H (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide) from IGM Resins.

[(F) component: antistatic agent]
F1: 3M (trademark) ionic liquid type antistatic agent FC4400 (tri-n-butylmethylammonium bistrifluoromethanesulfonimide), manufactured by 3M Japan Co., Ltd.

[(G) component: stabilizer]
G1: Irganox (registered trademark) 1010 (pentaerythritol-tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], hindered phenol antioxidant), manufactured by BASF Japan;
G2: Tinuvin® 292 (bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and methyl (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate Hindered amine light stabilizer (HALS)), manufactured by BASF Japan Ltd.

<Production of surface protective film (adhesive film)>
[Production of surface protection film 1]
A polyethylene terephthalate (PET) film having a thickness of 75 μm and having an AS treatment (antistatic treatment) on one side was prepared. The pressure-sensitive adhesive composition solution prepared above was applied to the surface of the PET film opposite to the AS-treated surface so that the thickness after drying was 75 μm. Then, the coating film on the PET film was dried in a hot air circulating oven at 120° C. for 5 minutes to form an adhesive layer on the PET film. Subsequently, the surface of the pressure-sensitive adhesive layer (the surface opposite to the PET film side) was coated with a release film (Diafoil (registered trademark) MRF38 (the surface of a PET film with a thickness of 38 μm was treated with a silicone release agent). product), manufactured by Mitsubishi Plastics, Inc.) were laminated. After that, the surface protective film 1 was produced by leaving the laminate in which the PET film, the adhesive layer, and the release film were laminated in this order under a test environment of 23° C.×50% RH for 7 days.

[Production of surface protective films 2 to 23]
Each surface protective film was produced in the same manner as in the production of surface protective film 1, except that adhesive composition solution 1 was changed to adhesive composition solutions 2 to 23.

<Evaluation 1 of surface protection film>
The surface protection films 1 to 18 produced above were evaluated as follows. Each evaluation result is shown in Table 1 and Table 2 below.

[Glass adhesive strength (adhesiveness)]
The surface protection film obtained above was cut into a piece having a width of 25 mm and a length of 200 mm. Next, the pressure-sensitive adhesive layer surface of the surface protective film after peeling off the release film was pressure-bonded to alkali-free glass (EAGLE XG (registered trademark), manufactured by Corning). Pressing was performed using a rubber roll having a mass of 2000 g (a roll covered with a rubber layer having a thickness of 6 mm, a width of 45 mm, a diameter (including the rubber layer) of 95 mm, and a spring hardness of the roll surface of 80 Hs). After pressing and leaving for 3 hours, the strength was measured when the surface protective film was peeled off from the non-alkali glass. Strength measurement was performed under the conditions of peeling the surface protective film from the alkali-free glass in the direction of 180° at a peeling speed of 2400 mm/min using a tensile tester under a test environment of 23°C and 50% RH. . And the value obtained by the said measurement was made into the glass adhesion force (g/25mm) of the surface protection film. In addition, it was determined that the adhesive strength to glass was good when it was 5 g/25 mm or more and 20 g/25 mm or less.

[Glass adhesion after UV irradiation (reworkability)]
The surface protection film obtained above was cut into a piece having a width of 25 mm and a length of 200 mm. Next, the pressure-sensitive adhesive layer surface of the surface protective film after peeling off the release film and alkali-free glass (EAGLE XG (registered trademark), manufactured by Corning) were pressure-bonded in the same manner as in the evaluation of the glass adhesive strength. After pressing and leaving for 3 hours, the surface protective film was irradiated with ultraviolet rays from the PET film side through the PET film to advance curing of the pressure-sensitive adhesive layer. The ultraviolet irradiation was performed under the conditions of 300 mJ/cm ² using a metal halide lamp in a test environment of 23° C.×50% RH. After that, the adhesive strength to glass was measured in the same manner as the measurement of the adhesive strength to glass. This value was defined as the glass adhesive strength (g/25 mm) of the surface protective film after UV irradiation. The glass adhesive strength after ultraviolet irradiation is not particularly limited as long as it is lower than the value of the glass adhesive strength, but it is considered to be particularly good when it is less than 5 g/25 mm.

[Punching workability (Frequency of falling off of adhesive layer)]
The release film was peeled off from the surface protective film obtained above. Then, with reference to the scratch hardness test method described in JIS K5600-5-4:1999, the presence or absence of adhesive residue was confirmed. Specifically, PEN made of SUS with a tip of 1 mm in diameter was pressed onto the surface of the adhesive layer at an angle of 45 degrees with loads of 500 g and 1000 g, and the presence or absence of adhesive scum was confirmed when the PEN was slid 2 cm. In addition, it is confirmed that the degree of generation of adhesive residue in the test corresponds to the frequency of occurrence of detachment of the adhesive layer during punching. Therefore, the test result can be used as an index of punching workability. The punchability of the surface protective film was evaluated according to the following criteria, and the following △ evaluation or higher was considered to be a good result:
(Evaluation criteria)
◎: No adhesive residue was generated under a load of 1000 g.
○: Adhesive residue was generated at a load of 1000 g, but no adhesive residue was generated at a load of 500 g.
Δ: Adhesive residue was generated in a part of the adhesive layer at a load of 500 g,
x: Adhesive scum occurred on the entire surface of the adhesive layer under a load of 500 g.

[Peeling electrification voltage]
A surface protective film and alkali-free glass (EAGLE XG (registered trademark), manufactured by Corning) were pressure-bonded in the same manner as in the measurement of the glass adhesive strength. After pressing and leaving for 3 hours, the surface protective film was peeled off from the non-alkali glass in the same manner as in the measurement of the glass adhesive strength. At this time, the potential of the surface protective film generated during peeling was measured. The potential was measured using a potential measuring device (STATIRON (registered trademark) DZ4, manufactured by Shishido Electrostatic Co., Ltd.) fixed at a height of 30 mm from the center of the film under a test environment of 23°C and 50% RH. rice field. The value obtained by the measurement was taken as the peeling electrostatic voltage (kV) of the surface protective film. It should be noted that the smaller the peeling electrification voltage, the better.

[Base material contamination]
Soken Chemical Co., Ltd. trade name: SK Dyne (registered trademark) 2137 as an adhesive, Soken Chemical Co., Ltd. trade name: TD-75 as a cross-linking agent, and Soken Chemical Co., Ltd. trade name as an additive: A-50 was added to ethyl acetate as a solvent at a solid content ratio of 100/0.1/0.1 (mass ratio) to prepare a solution. Next, using the obtained solution, a pressure-sensitive adhesive was applied onto a substrate, trade name: Cosmoshine (registered trademark) A4300 (polyester film, 75 μm thick) manufactured by Toyobo Co., Ltd., so that the film thickness after drying was 25 μm. formed a layer. Subsequently, a peeling PET 38E0010BG manufactured by Fujimori Industry Co., Ltd., which is a peeling film, was attached to the surface of the pressure-sensitive adhesive layer opposite to the substrate side. Thereafter, the obtained laminate of substrate/adhesive layer/release film was aged at room temperature for 1 week to prepare a pressure-sensitive adhesive sheet.

A surface protective film and alkali-free glass (EAGLE XG (registered trademark), manufactured by Corning) were pressure-bonded in the same manner as in the measurement of the glass adhesive strength. Then, after allowing to stand in an environment of 40° C. for 2 weeks, the surface protective film was peeled off from the non-alkali glass in the same manner as the measurement of the glass adhesion force.

Next, the above-prepared pressure-sensitive adhesive sheets were pressure-bonded to the surface of the new alkali-free glass and the peeled surface of the alkali-free glass from which the surface protective film had been peeled off. Pressing was performed using a rubber roll having a mass of 2000 g (a roll covered with a rubber layer having a thickness of 6 mm, a width of 45 mm, a diameter (including the rubber layer) of 95 mm, and a spring hardness of the roll surface of 80 Hs). Subsequently, the strength when the adhesive sheet was peeled off from each of these alkali-free glasses was measured. The strength measurement was performed under the condition that the pressure-sensitive adhesive sheet was peeled from the non-alkali glass in the direction of 180° at a peel speed of 300 mm/min using a tensile tester under a test environment of 23°C and 50% RH. Then, the ratio of the strength (g/25 mm) when the adhesive sheet is peeled from the alkali-free glass after peeling the surface protective film to the strength (g/25 mm) when the adhesive sheet is peeled from the new alkali-free glass ( %) was calculated. Then, the glass contamination resistance of the surface protective film was evaluated according to the following criteria, and the following △ evaluation or higher was considered to be a good result:
(Evaluation criteria)
◎: The ratio of the strength (g/25 mm) when the adhesive sheet is peeled off from the alkali-free glass after peeling off the surface protective film is 90% or more,
○: The ratio of the strength (g/25 mm) when the adhesive sheet is peeled off from the alkali-free glass after peeling off the surface protective film is 80% or more and less than 90%.
Δ: The ratio of the strength (g/25 mm) when the adhesive sheet is peeled off from the alkali-free glass after peeling off the surface protective film is 70% or more and less than 80%.
x: The ratio of the strength (g/25 mm) when the pressure-sensitive adhesive sheet was peeled off from the alkali-free glass after peeling off the surface protective film was less than 70%.

[Wettability test]
The surface protection film obtained above was cut into a piece having a width of 25 mm and a length of 200 mm. Next, the adhesive layer surface (FIG. 12) of the surface protective film (FIG. 11) after peeling off the release film, and alkali-free glass (EAGLE XG (registered trademark), manufactured by Corning) (FIG. 13) by hand while one end surface of the surface protective film is in contact with the non-alkali glass so that the angle between the longitudinal direction of the surface protective film and the surface of the non-alkali glass is 20 to 30 °. held. After that, the hand was released from the surface protective film, and the surface protective film and the non-alkali glass were laminated only by the weight of the surface protective film (arrow in FIG. 1). At this time, the time required for the surface of the pressure-sensitive adhesive layer of the surface protection film to wet and spread on the surface of the alkali-free glass was visually measured. Then, the wettability of the surface protective film was evaluated according to the following criteria, and the results were considered to be good or better than the following △ evaluation:
(Evaluation criteria)
◎: Wetting and spreading time is less than 3 seconds,
○: Wetting and spreading time is 3 seconds or more and less than 5 seconds,
△: Wetting and spreading time is 5 seconds or more and less than 10 seconds,
x: Time for wetting and spreading is 10 seconds or more.

[Transmittance (%)]
The surface protective film obtained above was cut into a piece having a width of 25 mm and a length of 50 mm, and the release film was peeled off. Next, the surface protective film was pressure-bonded to non-alkali glass (EAGLE XG (registered trademark), manufactured by Corning) so that the surface of the pressure-sensitive adhesive layer of the surface protective film was in contact with the non-alkali glass to prepare a test sample. The transmittance (%) of this test sample was measured using a haze meter (NDH500W, manufactured by Nippon Denshoku Industries Co., Ltd.).

[HAZE (%)]
The surface protective film obtained above was cut into a piece having a width of 25 mm and a length of 50 mm, and the release film was peeled off. Next, the surface protective film was pressure-bonded to non-alkali glass (EAGLE XG (registered trademark), manufactured by Corning) so that the surface of the pressure-sensitive adhesive layer of the surface protective film was in contact with the non-alkali glass to prepare a test sample. HAZE (%) of this test sample was measured using a haze meter (NDH500W, manufactured by Nippon Denshoku Industries Co., Ltd.).

As shown in Tables 1 and 2 above, surface protection films 13 to 18 have adhesive layers formed from thermosetting adhesive compositions 13 to 18 according to comparative examples outside the scope of the present invention. . These thermosetting pressure-sensitive adhesive compositions contain an excessive amount of component (D) or do not contain component (D). Surface protective films 13 to 15 and 18 were confirmed to be inferior in punching workability and wettability, and to have high haze. Moreover, it was confirmed that the surface protective films 16 and 17 have a large adhesive force to glass.

On the other hand, surface protection films 1 to 12 have adhesive layers formed from thermosetting adhesive compositions 1 to 12 according to examples within the scope of the present invention. These surface protective films 1 to 12 were confirmed to have both adhesiveness and reworkability at high levels. In addition, it was confirmed that these surface protective films are less likely to cause the pressure-sensitive adhesive layer to come off, have a small peeling electrification voltage, reduce substrate contamination, and have good wettability. Moreover, it was confirmed that these surface protection films had high transmittance and low HAZE, and had high transparency.

<Evaluation 2 of surface protection film>
The surface protective films 19 to 23 produced above were evaluated by the same method and evaluation criteria as in Evaluation 1 of the surface protective film above. Properties, wettability tests, transmittance and haze were evaluated. In addition, the surface protection films 1 and 19 to 23 produced above were evaluated as follows. Each evaluation result is shown in Table 3 below.

[Glass adhesion ratio]
The surface protection film obtained above was cut into a piece having a width of 25 mm and a length of 200 mm. Next, the pressure-sensitive adhesive layer surface of the surface protective film after peeling off the release film and alkali-free glass (EAGLE XG (registered trademark), manufactured by Corning) were pressure-bonded in the same manner as in the evaluation of the glass adhesive strength. Subsequently, the non-alkali glass to which the surface protection film was pressure-bonded was left for 15 days (360 hours) in a test environment of 23° C.×50% RH under LED illumination (500 Lux). After that, the strength when the surface protective film was peeled off from the non-alkali glass was measured in the same manner as the evaluation of the glass adhesive strength, and this value was taken as the glass adhesive strength (g / 25 mm) after the LED stability test. The value obtained by dividing the glass adhesion value after the LED stability test by the glass adhesion value evaluated above was defined as the glass adhesion ratio. Although the glass adhesive strength ratio is not particularly limited, it is considered to be particularly good when it is 0.8 or more and 1.2 or less.

[Glass adhesive force ratio after UV irradiation]
The surface protection film obtained above was cut into a piece having a width of 25 mm and a length of 200 mm. Next, the pressure-sensitive adhesive layer surface of the surface protective film after peeling off the release film and alkali-free glass (EAGLE XG (registered trademark), manufactured by Corning) were pressure-bonded in the same manner as in the evaluation of the glass adhesive strength. Subsequently, the non-alkali glass to which the surface protective film was crimped was left for 15 days (360 hours) in a test environment of 23° C.×50% RH under LED illumination (500 Lux). Then, the surface protective film after standing was irradiated with ultraviolet rays in the same manner as in the evaluation of the adhesive strength to glass after irradiation with ultraviolet rays, so that the curing of the pressure-sensitive adhesive layer progressed. After that, the adhesive strength to glass was measured in the same manner as the measurement of the adhesive strength to glass. This value was taken as the glass adhesive strength after UV irradiation (g/25 mm) after the LED stability test. The value obtained by dividing the value of the glass adhesive strength after UV irradiation after the LED stability test by the value of the glass adhesive strength after UV irradiation evaluated above was taken as the glass adhesive strength ratio after UV irradiation. Although the glass adhesive force ratio after ultraviolet irradiation is not particularly limited, it is considered to be particularly good when it is 1.2 or less.

As shown in the results in Table 3 above, surface protective films 19 to 23 have pressure-sensitive adhesive layers formed from pressure-sensitive adhesive compositions 19 to 23 according to Examples within the scope of the present invention. These adhesive compositions contain the (G) component. Surface protective films 19 to 23 were in a better range than surface protective film 1 containing no stabilizer in glass adhesion ratio and glass adhesion ratio after UV irradiation. From this, it was confirmed that surface protective films 19 to 23 contained component (G) to suppress the progress of the photo-curing reaction of the pressure-sensitive adhesive layer under LED illumination.

This result indicates that the surface protective film according to one embodiment of the present invention does not require light shielding during storage by further containing the component (G), thereby further improving storage stability.

1 Surface protection film after peeling off the release film,
2 adhesive layer surface,
3 Alkali-free glass.

Claims (14)

(A) component: a urethane prepolymer having two or more hydroxyl groups,
(B) component: polyfunctional (meth)acrylate,
(C) component: a cross-linking agent,
(D) component: crosslinked particles,
(E) component: photoradical initiator, and (F) component: antistatic agent,
contains
The content of the component (D) with respect to 100 parts by mass of the component (A) is 0.01 parts by mass or more and 10 parts by mass or less,
The pressure-sensitive adhesive composition , wherein the component (D) has an average particle size of 0.5 μm or more and 30 μm or less . 2. The pressure-sensitive adhesive composition according to claim 1, wherein the adhesive strength of the pressure-sensitive adhesive composition is reduced by light irradiation. The content of the component (B) with respect to 100 parts by mass of the component (A) is 10 parts by mass or more and 150 parts by mass or less,
3. The pressure-sensitive adhesive composition according to claim 1, wherein the hydroxyl value of component (B) is 100 mg·KOH/g or less. The component (C) contains a compound having an isocyanate group,
The equivalent ratio of the total amount of isocyanate groups of the compound having an isocyanate group to the total amount of hydroxyl groups of the component (A) (NCO (total) (mol) / OH (mol)) is 0.2 or more and 10 or less. The adhesive composition according to any one of claims 1 to 3. The component (C) contains a compound having an isocyanate group,
The compound having an isocyanate group includes a bifunctional isocyanate,
The equivalent ratio of the isocyanate group amount of the bifunctional isocyanate to the total amount of isocyanate groups of the isocyanate (NCO (bifunctional) (mol) / NCO (total) (mol)) is more than 0 and less than 1, The pressure-sensitive adhesive composition according to any one of claims 1-4. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the component (C) contains a trifunctional or higher isocyanate. The pressure-sensitive adhesive composition according to any one of claims 1 to 6, wherein the component (A) contains a urethane prepolymer having a polyether skeleton and two or more hydroxyl groups. Claim 7, wherein the urethane prepolymer having a polyether skeleton and two or more hydroxyl groups is a urethane prepolymer having a polyether skeleton and two or more hydroxyl groups and (meth)acryloyloxy groups. The pressure-sensitive adhesive composition according to . The content of component (E) with respect to 100 parts by mass of component (A) is 0.1 parts by mass or more and 10 parts by mass or less, according to any one of claims 1 to 8 . Adhesive composition. 10. The content of component (F) with respect to 100 parts by mass of component (A) is 0.5 parts by mass or more and 10 parts by mass or less, according to any one of claims 1 to 9 . Adhesive composition. Component (G): The pressure-sensitive adhesive composition according to any one of claims 1 to 10 , further comprising a stabilizer. 12. The pressure-sensitive adhesive composition according to any one of claims 1 to 11 , wherein the component (G) stabilizer does not exceed 5 parts by mass relative to 100 parts by mass of the component (A). A cured product of the adhesive composition according to any one of claims 1 to 12 . A surface protective film comprising a resin film, and an adhesive layer composed of the cured product according to claim 13 and arranged on one side of the resin film.

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