JP7235863B2 - Adhesive composition and adhesive processed product - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive composition and an adhesive processed product.

Adhesives (also referred to as pressure-sensitive adhesives) are easy to use and have adhesiveness to various objects such as plastics, papers, metals, and glass. It is used as an adhesive layer in adhesive processed products. As the composition (adhesive composition) used as the adhesive, a composition having an acrylic resin or a styrene resin (such as a styrene block copolymer) as a base polymer is generally used.

In particular, a pressure-sensitive adhesive composition containing an acrylic resin as a base polymer is known to have excellent transparency and adhesion to polar adherends such as papers, metals and glass.

On the other hand, along with the thinning of electronic devices and the like, there is a growing demand for thinner double-sided tapes that bond internal members together. Therefore, the pressure-sensitive adhesive composition is desired to have more sufficient pressure-sensitive adhesiveness and adhesion even when the pressure-sensitive adhesive layer is made thinner.

In response to the above requirements, a method of adding a tackifying resin such as a rosin-based resin, a terpene-based resin, and a petroleum-based resin to an acrylic pressure-sensitive adhesive composition to further increase the adhesiveness of the pressure-sensitive adhesive composition has been proposed. . For example, in Patent Document 1, by adding a tackifying resin having low compatibility with a (meth)acrylic polymer, such as a rosin-based resin, to an acrylic pressure-sensitive adhesive composition, the adhesive strength at both room temperature and high temperature is improved. It is stated that it can be performed. Patent Document 1 describes that the tackifying resin is added so that the haze value of the pressure-sensitive adhesive composition formed into a film is 15 to 95%.

JP-A-64-16882

Patent Literature 1 describes that the addition of a tackifying resin such as the rosin-based resin can further enhance the adhesiveness of the adhesive composition. However, as described in Patent Document 1, the addition of the tackifying resin lowers the transparency of the pressure-sensitive adhesive composition.

The present invention has been made in view of the above circumstances, and provides an adhesive composition capable of obtaining a thin adhesive layer having sufficient adhesiveness and high transparency, and the adhesive composition. An object thereof is to provide an adhesive processed product obtained by processing.

As a result of intensive studies, the inventors of the present invention have found that the above problems can be solved by the following configuration. That is, the present invention relates to the following [1] to [6].
[1] 47 parts by mass or more and 99 parts by mass or less (meth)acrylic resin (A), 0.5 parts by mass or more and 50 parts by mass or less of (meth)acrylic resin (A) different (co)polymer (B ), and 0.5 parts by mass or more and 3 parts by mass or less of the cross-linking agent (C) (however, the (meth) acrylic resin (A), the (co) polymer (B) and the cross-linking agent (C) The total content is 100 parts by mass.),
The (meth)acrylic resin (A) satisfies the following (A-1) and (A-2), and
The (co)polymer (B) satisfies all of the following (B-1) to (B-5),
Adhesive composition.
(A-1) It contains a structural unit derived from a (meth)acrylate having an alkyl group having 1 to 12 carbon atoms and a structural unit derived from a (meth)acrylate containing a hydroxyl group.
(A-2) The glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) is in the range of -80°C or higher and 0°C or lower.
(B-1) Containing structural units derived from isopropenyltoluene in an amount of 20 mol % or more based on the total amount of the structural units.
(B-2) The softening point measured according to JIS K2207 is in the range of 90°C or higher and 130°C or lower.
(B-3) The glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) is in the range of 40°C or higher and 80°C or lower.
(B-4) The content of compounds having a molecular weight of 400 or less in terms of polystyrene measured by gel permeation chromatography (GPC) is 10% by mass or less.
(B-5) The polystyrene-equivalent number-average molecular weight (Mn) measured by gel permeation chromatography (GPC) is in the range of 750 or more and 1000 or less, and the z-average molecular weight (Mz) is in the range of 1200 or more and 2000 or less. and the dispersity (Mw/Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is 1.5 or less.
[2] The adhesive composition according to [1], wherein the (co)polymer (B) satisfies the following (B-6).
(B-6) Consisting of styrene, α-methylstyrene, indene, vinyltoluene, and an unsaturated aliphatic hydrocarbon compound having 4 or 5 carbon atoms in an amount of 1 mol% or more and 80 mol% or less of the total amount of the structural units It contains structural units derived from monomers selected from the group.
[3] A processed adhesive product obtained by processing the adhesive composition according to [1] or [2], which is a tape, label, sheet or double-sided tape.
[4] The adhesive processed product according to [3], which has an adhesive layer with a thickness of 5 μm or more and 50 μm or less.
[5] The adhesive processed product according to [3] or [4], which has a total light transmittance of 87% or more as measured according to JIS K7361.
[6] The adhesive processed product according to any one of [3] to [5], which has an adhesive strength of 9 N/25 mm or more as measured by a 180° peel test using SUS as an adherend.

According to the present invention, there are provided an adhesive composition capable of obtaining a thin adhesive layer having sufficient adhesiveness and high transparency, and an adhesive processed product obtained by processing the adhesive composition. provided.

FIG. 1 is a graph showing the relationship between the total light transmittance and the adhesive force when the thickness of the adhesive layer is 10 μm in Example 1 and Comparative Examples 1 to 3. FIG.

One embodiment of the present invention relates to an adhesive composition containing (meth)acrylic resin (A), (co)polymer (B), and crosslinker (C). In the present specification, (meth)acryl means “acrylic or methacrylic”, (meth)acrylate means “acrylate or methacrylate”, and (co)polymer means “homopolymer or copolymer”. polymer".

[(Meth) acrylic resin (A)]
The (meth)acrylic resin (A) is a (co)polymer of acrylic monomers or methacrylic monomers.

The (meth)acrylic resin (A) satisfies the following requirements (A-1) and (A-2).

(A-1) It contains a structural unit derived from a (meth)acrylate having an alkyl group having 1 to 12 carbon atoms and a structural unit derived from a (meth)acrylate containing a hydroxyl group.
(A-2) The glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) is in the range of -80°C or higher and 0°C or lower.

(Regarding requirement (A-1))
Requirement (A-1) is a requirement for increasing the adhesiveness of the adhesive composition according to the present embodiment.

Specifically, when the (meth)acrylic resin (A) contains a structural unit derived from a (meth)acrylate having an alkyl group having 1 to 12 carbon atoms, the glass of the (meth)acrylic resin (A) The transition temperature (Tg) increases and the adhesive composition becomes more adhesive.

From the above viewpoint, the (meth)acrylate having an alkyl group having 1 to 12 carbon atoms is preferably a (meth)acrylate having an alkyl group having 1 to 10 carbon atoms, and the number of carbon atoms is 2. A (meth)acrylate having at least 8 alkyl groups is more preferable. In addition, the alkyl group may be linear or branched.

Examples of (meth)acrylates having an alkyl group having 1 to 12 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and (meth)acrylic acid. Isopropyl, n-butyl (meth)acrylate, isobutyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, (meth)acrylic Examples include isooctyl acid, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, and lauryl (meth)acrylate.

In the (meth)acrylic resin (A), the content of the structural unit derived from the (meth)acrylate having an alkyl group having 1 or more and 12 or less carbon atoms is 50 mol% or more and 99 mol with respect to the total amount of the structural units. % or less, more preferably 55 mol % or more and 95 mol % or less, and even more preferably 60 mol % or more and 90 mol % or less.

Further, when the (meth)acrylic resin (A) contains a structural unit derived from a (meth)acrylate containing a hydroxyl group, the number of crosslink points by the crosslinker (C) increases, so that the crosslink density of the adhesive composition increases. It becomes easier to increase the molecular weight. Such an adhesive composition does not easily follow the surface of an adherend even when pressed, and is less likely to cause a decrease in adhesiveness during pressure bonding.

Examples of (meth)acrylates containing hydroxyl groups include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate and N-methylol(meth)acrylamide. Among these, from the above viewpoint, the (meth)acrylate containing a hydroxyl group is preferably hydroxyethyl (meth)acrylate.

In the (meth)acrylic resin (A), the content of structural units derived from the (meth)acrylate containing a hydroxyl group is 0.1 mol% or more and 5 mol% or less with respect to the total amount of the structural units. It is preferably 0.2 mol % or more and 3 mol % or less, and even more preferably 0.3 mol % or more and 2 mol % or less.

The (meth)acrylic resin (A) contains a functional group capable of forming a crosslink, which is different from the (meth)acrylate having an alkyl group having 1 to 12 carbon atoms or the (meth)acrylate containing a hydroxyl group. It may be a copolymer having a structural unit derived from a monomer (or oligomer) having. Examples of monomers having functional groups capable of forming crosslinks include (meth)acrylic acid and (meth)acrylamide.

In addition, the (meth)acrylic resin (A) may be a copolymer having a structural unit derived from a vinyl-based monomer other than the above, if necessary. Examples of such vinyl monomers include styrene, vinyl acetate, and the like.

(Regarding requirement (A-2))
Requirement (A-2) is a requirement for suitably exhibiting the adhesiveness of the adhesive composition of the present embodiment over a wider temperature range.

Specifically, the (meth)acrylic resin (A) is a copolymer having a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) in the range of −80° C. or higher and 0° C. or lower. , the adhesive composition formed into a thin adhesive layer can develop adhesiveness in a wide temperature range. From the above viewpoint, the (meth)acrylic resin (A) preferably has a glass transition temperature (Tg) in the range of -70°C or higher and -5°C or lower, and in the range of -60°C or higher and -10°C or lower. is more preferable.

The glass transition temperature (Tg) of the (meth)acrylic resin (A) can be adjusted within the above range by changing the monomers to be polymerized and the ratio thereof.

In the present invention, the glass transition temperature (Tg) of the (meth)acrylic resin (A) can be calculated from a theoretically calculated value determined by the following FOX formula.
1/Tg=W1/Tg1+W2/Tg2+...+Wn/Tgn
(Wherein, Tg is the glass transition temperature (K) of the acrylic resin (A), W1, W2, ..., Wn are the weight fractions of each monomer, Tg1, Tg2, ... , Tgn is the glass transition temperature of the homopolymer of each monomer)
As the glass transition temperature of the homopolymer used for the above calculation, the value described in the literature can be used.

(Synthesis method)
The (meth)acrylic resin (A) can be synthesized by a known polymerization method using monomers (or oligomers) as materials for the structural units described above. The polymerization method is not particularly limited as long as it is a radical polymerization method including a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and the like. Among these, the glass transition temperature (Tg) and other properties of the (meth)acrylic resin (A) are easy to control, and the (meth)acrylic resin (A) having desired properties is easy to synthesize. Legal is preferred.

A polymerization initiator may be used during the polymerization. Examples of the polymerization initiators include dicumyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis(t-butylperoxy)cyclohexane, α,α'- azobisisobutyronitrile, acetyl peroxide, t-butyl peroxypivalate, t-butyl hydroperoxide, cumene hydroperoxide, t-hexyl peroxypivalate, 2,2'-azobis-(2,4 -dimethylvaleronitrile), lauryloyl peroxide, t-butyl peroxyneohexanoate, di-t-butyl peroxide, azodicyclohexylcarbonitrile, dimethyl α,α-azodiisobutyrate, succinic acid peroxide, dicumene Peroxides, dichlorobenzoyl peroxide, and the like.

Examples of solvents used in the solution polymerization include ethyl acetate, butyl acetate, benzene, toluene, xylene, cyclohexane, methyl ethyl ketone and the like.

[(Co)polymer (B)]
The (co)polymer (B) is a (co)polymer that is different from the (meth)acrylic resin (A) and that satisfies all of the following (B-1) to (B-5): It is a coalescence.

(B-1) Containing structural units derived from isopropenyltoluene in an amount of 20 mol % or more based on the total amount of the structural units.
(B-2) The softening point measured according to JIS K2207 is in the range of 90°C or higher and 130°C or lower.
(B-3) The glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) is in the range of 40°C or higher and 80°C or lower.
(B-4) The content of compounds having a molecular weight of 400 or less in terms of polystyrene measured by gel permeation chromatography (GPC) is 10% by mass or less.
(B-5) The polystyrene-equivalent number-average molecular weight (Mn) measured by gel permeation chromatography (GPC) is in the range of 750 or more and 1000 or less, and the z-average molecular weight (Mz) is in the range of 1200 or more and 2000 or less. and the dispersity (Mw/Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is 1.5 or less.

(Regarding requirement (B-1))
Requirement (B-1) is a requirement for increasing the adhesiveness without reducing the transparency of the adhesive composition according to the present embodiment.

Although the reason for this is not clear, the (co)polymer (B) contains 20 mol% or more of isopropenyltoluene (o-isopropenyltoluene, m-isopropenyltoluene, p-isopropenyltoluene) relative to the total amount of its structural units. containing a propenyl toluene isotope), the (meth)acrylic resin (A) and the (co)polymer (B) become more compatible, and the (co)polymer (B) is likely to be finely dispersed in the (meth)acrylic resin (A). The (co)polymer (B) containing structural units derived from isopropenyltoluene has a solubility parameter (SP value) of 8.7 to 8.9, and the SP value of the (meth)acrylic resin (8.6 to 9 .1), the difference in SP value becomes smaller, so it is presumed to be easily compatible with the (meth)acrylic resin (A).

In the (co)polymer (B), the content of structural units derived from isopropenyltoluene is preferably 50 mol% or more, more preferably 70 mol% or more, relative to the total amount of the structural units. , more preferably 85 mol % or more. Although the upper limit of the content of the structural unit derived from isopropenyltoluene is not particularly limited, it can be 100 mol% or less, preferably 98 mol% or less, and more preferably 96 mol% or less. , more preferably less than 95 mol %.

(Regarding requirement (B-2))
Requirement (B-2) is a requirement for adjusting the viscosity of the pressure-sensitive adhesive composition according to the present embodiment to such an extent that the coating properties on the substrate are excellent.

Specifically, when the softening point of the (co)polymer (B) measured by a differential scanning calorimeter (DSC) is in the range of 90° C. or higher and 130° C. or lower, the adhesive composition containing a solvent is particularly Since it has an appropriate viscosity, the adhesive composition can be more easily applied to the substrate. From the above viewpoint, the (co)polymer (B) preferably has a softening point in the range of 95° C. or higher and 125° C. or lower, more preferably 100° C. or higher and 120° C. or lower, and 105° C. or higher. It is more preferably in the range of 115° C. or less.

The softening point of the (co)polymer (B) can be adjusted within the above range by adjusting the type of monomers to be copolymerized, the molecular weight, and the molecular weight distribution.

(Regarding requirement (B-3))
Requirement (B-3) is a requirement for adjusting both transparency and adhesiveness to suitable ranges while increasing the heat resistance of the adhesive composition of the present embodiment.

Specifically, when the glass transition temperature (Tg) of the (co)polymer (B) measured according to JIS K2207 is 40°C or higher, the heat resistance of the adhesive composition is further enhanced. Moreover, when the (co)polymer (B) has a glass transition temperature (Tg) of 80° C. or less, both the transparency and the adhesiveness of the adhesive composition tend to fall within suitable ranges. From the above viewpoint, the (co)polymer (B) preferably has a glass transition temperature (Tg) in the range of 45° C. or higher and 78° C. or lower, more preferably in the range of 50° C. or higher and 75° C. or lower. , 55° C. or higher and 70° C. or lower.

The glass transition temperature (Tg) of the (co)polymer (B) can be adjusted within the above range by adjusting the type of monomer to be copolymerized, the molecular weight, and the molecular weight distribution.

In the present invention, the glass transition temperature (Tg) of the (co)polymer (B) can be calculated from a theoretically calculated value determined by the FOX formula described above.

(Regarding requirement (B-4))
Requirement (B-4) is a requirement for further enhancing the adhesiveness and heat resistance of the adhesive composition according to the present embodiment.

Specifically, the content of compounds having a molecular weight of 400 or less in terms of polystyrene measured by gel permeation chromatography (GPC) of the (co)polymer (B) is 10% by mass or less, and an extremely low molecular weight component Since the content of is low, the heat resistance can be further improved while maintaining the adhesiveness of the adhesive composition. From the above viewpoint, the content of the compound having a molecular weight of 400 or less in the (co)polymer (B) is preferably 8% by mass or less, more preferably 6% by mass or less. Although the lower limit of the content of the compound having a molecular weight of 400 or less is not particularly limited, it can be 0% by mass (measurement limit) or more.

The content of compounds with a molecular weight of 400 or less is the integral molecular weight distribution curve measured in terms of polystyrene by the GPC method (gel permeation chromatography method) using tetrahydrofuran as a solvent, and is between the curve with a molecular weight of 400 or less and the baseline. It can be measured by calculating the area of the region by integration.

The content of compounds having a molecular weight of 400 or less in the (co)polymer (B) can be adjusted to the above range by subjecting the (co)polymer (B) to vacuum distillation at a heating temperature of 250° C. or less.

(Regarding requirement (B-5))
Requirement (B-5) is a requirement for increasing the adhesiveness without reducing the transparency of the adhesive composition according to the present embodiment.

Specifically, the (co)polymer (B) has a polystyrene-equivalent number-average molecular weight (Mn) of 750 or more and 1000 or less, measured by gel permeation chromatography (GPC), and has a z-average molecular weight of (Mz) is in the range of 1200 or more and 2000 or less, and the dispersity (Mw/Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is 1.5 or less. The (co)polymer (B) that satisfies the requirement (B-5) has a relatively small molecular weight, and thus enhances the wettability of the pressure-sensitive adhesive composition to the substrate and increases the adhesiveness of the pressure-sensitive adhesive composition. It is estimated to be. In addition, the (co)polymer (B) that satisfies the requirement (B-5) has a small variation in molecular weight, so it is easily compatible with the (meth)acrylic resin (A), and the adhesive composition has higher transparency. is estimated to be able to obtain

From the above viewpoint, the (co)polymer (B) preferably has a number average molecular weight (Mn) of 770 or more and 980 or less, more preferably 790 or more and 950 or less, and 800 or more and 900 or less. is more preferred.

From the above viewpoint, the (co)polymer (B) preferably has a z-average molecular weight (Mz) of 1,300 or more and 1,900 or less, more preferably 1,400 or more and 1,800 or less.

From the above viewpoint, the (co)polymer (B) has a dispersity (Mw/Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), of 1.45 or less. is preferred, and 1.4 or less is more preferred. Although the lower limit of Mw/Mn is not particularly limited, it can be 1 or more.

The number average molecular weight (Mn), the z average molecular weight (Mz), and the dispersity (Mw/Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), of the (co)polymer (B) can be adjusted to the above range by the type of monomers to be copolymerized or distillation under reduced pressure.

(About other requirements)
The (co)polymer (B) is preferably a (co)polymer that further satisfies (B-6) below.

(B-6) 1 mol% or more and 80 mol% or less of monomers selected from the group consisting of styrene, α-methylstyrene, indene, vinyltoluene and unsaturated aliphatic hydrocarbon compounds having 4 or 5 carbon atoms Contains structural units.

Structural units derived from these monomers maintain the transparency of the adhesive composition by increasing the compatibility of the (co)polymer (B) with the (meth)acrylic resin (A), The molecular weight distribution (Mw/Mn) of coalescence (B) can be easily adjusted within the above range.

Examples of the unsaturated aliphatic hydrocarbon compound having 4 or 5 carbon atoms include, as a main component, an unsaturated aliphatic hydrocarbon compound having 4 or 5 carbon atoms, which is produced as a by-product during petroleum refining and cracking, _C4 distillation fractions and _C5 fractions.

The above _C4 fraction and _C5 fraction are fractions having a boiling point range of usually -15 to +45°C under normal pressure. The _C4 and _C5 fractions are 1-butene, isobutene, 2-butene, 1,3-butadiene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2- Including polymerizable monomers such as pentene, isoprene, 1,3-pentadiene, and cyclopentadiene.

The above _C4 fraction and _C5 fraction are light oil fractions including gas fractions by-produced during atmospheric distillation (topping) of crude oil in oil refineries, etc., by-products in the cracking or reforming process of petroleum. Petroleum fractions, including similar light oil fractions and light oil fractions containing gas obtained in petroleum naphtha cracking in petrochemical plants, etc., may be used as is, or may be subjected to distillation, extraction or other treatment. In addition, it may be used as a desired fraction.

From the above viewpoint, the (co)polymer (B) is derived from styrene, α-methylstyrene, indene, vinyltoluene or an unsaturated aliphatic hydrocarbon compound having 4 or 5 carbon atoms relative to the total amount of its structural units. The content of structural units is preferably 2 mol % or more and 60 mol % or less, more preferably 4 mol % or more and 40 mol % or less, and even more preferably 5 mol % or more and 20 mol % or less. .

(About other monomers)
The (co)polymer (B) may be a copolymer having structural units derived from monomers other than isopropenyltoluene and the like, if necessary. The softening point and glass transition temperature (Tg) of the (co)polymer (B) can be easily adjusted by using a copolymer containing structural units derived from the other monomers.

Examples of the other monomers include vinyl aromatic compounds and unsaturated aliphatic hydrocarbon compounds other than 4 or 5 carbon atoms.

Examples of the vinyl aromatic compound include styrenic monomers including substituted styrene having a substituent on the aromatic ring and substituted α-methylstyrene having a substituent on the aromatic ring. Examples of substituents on the aromatic ring include alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, and halogen atoms. The vinyl aromatic compound may have one substituent on the aromatic ring, or two or more substituents on the aromatic ring.

Specific examples of the substituted styrene include methylstyrene (except α-methylstyrene), ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene. , pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene. including styrene.

(Synthesis method)
The (co)polymer (B) can be synthesized by a known polymerization method using isopropenyltoluene and other optionally copolymerized monomers. The polymerization is preferably cationic polymerization, more preferably in the presence of a Friedel-Crafts catalyst.

The above Friedel-Crafts catalysts include aluminum chloride, aluminum bromide, dichloromonoethylaluminum, titanium tetrachloride, tin tetrachloride, boron trifluoride, and various complexes such as boron trifluoride ether complexes or phenol complexes. is not particularly limited as long as it is a known Friedel-Crafts catalyst including Among these, a phenol complex of boron trifluoride is preferred. The amount of the Friedel-Crafts catalyst used can be 0.05 parts by mass or more and 5 parts by mass or less with respect to a total of 100 parts by mass of the raw material monomers, and is 0.1 parts by mass or more and 2 parts by mass or less. is preferred.

The polymerization reaction is preferably carried out using a solvent so that the concentration of the raw material monomer is about 10 to 60% by mass, from the viewpoints of removing reaction heat generated during the polymerization reaction, suppressing the viscosity of the reaction liquid, adjusting the molecular weight, and the like. . Examples of such solvents include aliphatic hydrocarbons such as pentane, hexane, heptane, and octane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclohexane; and toluene, xylene, ethylbenzene, and mesitylene. Aromatic hydrocarbons including, etc. are included. One of these solvents may be used alone, or two or more of them may be used in combination.

The polymerization can be carried out by polymerizing raw material monomers in the solvent in the presence of the catalyst in a reactor. The above polymerization can be carried out in one stage, but is preferably carried out in multiple stages. The polymerization temperature at this time varies depending on the raw material composition, the target molecular weight range, etc., but is preferably -50 to +50°C. Further, the reaction time at this time is preferably 10 minutes to 10 hours. After the polymerization is completed, the catalyst is decomposed using a basic aqueous solution or a basic compound containing an alcohol such as methanol, washed with water, and unreacted raw materials and solvents are stripped or distilled. Except for this, the desired (co)polymer (B) can be obtained.

The removal of the unreacted raw materials and solvents can be carried out, for example, by atmospheric distillation, reduced pressure distillation, steam distillation, etc., an operation of concentrating using the difference in vapor pressure of each substance, and an open column, a flash column, etc. It can be carried out by a method of concentrating using differences in affinity and molecular size for fillers such as silica gel. Among these, vacuum distillation is preferable from the viewpoint of thermal decomposition suppression and concentration efficiency. The range of pressure reduction is not particularly limited. On the other hand, from the viewpoint of suppressing thermal decomposition of the (co)polymer (B), the heating temperature is preferably 250° C. or lower, more preferably 230° C. or lower, and 210° C. or lower. More preferred.

[Crosslinking agent (C)]
The cross-linking agent (C) cross-links the (meth)acrylic resin (A) to further enhance the adhesiveness of the adhesive composition of the present embodiment.

Examples of crosslinkers (C) include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, and resorcin diglycidyl ether. Epoxy compounds containing ethers, tetramethylene diisocyanate, hexamethylene diisocyanate, toluenediisocyanate triadduct of trimethylolpropane, and isocyanate compounds containing polyisocyanates, trimethylolpropane-tri-β-aziridinylpropionate , tetramethylolmethane-tri-β-aziridinylpropionate, N,N′-diphenylmethane-4,4′-bis(1-aziridinecarboxamide), N,N′-hexamethylene-1,6-bis (1-aziridine carboxamide), N,N'-toluene-2,4-bis(1-aziridine carboxamide), trimethylolpropane-tri-β-(2-methylaziridine) propionate, and other aziridine compounds; and melamine-based compounds including hexamethoxymethylolmelamine and the like. The cross-linking agent (C) may be used singly or in combination of two or more.

The cross-linking agent (C) has the number of functional groups capable of bonding with the (meth)acrylic resin (A) in the cross-linking agent (C) (when the cross-linking agent (C) contains blocked isocyanate, the number of functional groups generated by dissociation of the blocking agent ) is preferably blended to the extent that the number of functional groups does not exceed the number of functional groups possessed by the (meth)acrylic resin (A), but when new functional groups are generated by the cross-linking reaction or the progress of the cross-linking reaction is slow Sometimes, a larger amount may be blended.

[Content ratio]
The adhesive composition related to the present embodiment is 47 parts by mass or more when the total content of the (meth)acrylic resin (A), the (co)polymer (B) and the cross-linking agent (C) is 100 parts by mass. 99 parts by mass or less (meth)acrylic resin (A), 0.5 parts by mass or more and 50 parts by mass or less of (co)polymer (B), and 0.5 parts by mass or more and 3 parts by mass or less of a cross-linking agent ( C).

When the content of the (meth)acrylic resin (A) is 47 parts by mass or more, a larger amount of the (meth)acrylic resin (A) is contained in the adhesive composition. Since the cross-linking density is higher and the molecular weight is higher, the pressure-sensitive adhesive composition is less prone to decrease in adhesion due to following the surface of the adherend during pressure bonding. When the content of the (meth)acrylic resin (A) is 99 parts by mass or less, a larger amount of the (co)polymer (B) and the cross-linking agent (C) will be contained in the adhesive composition. Therefore, the adhesiveness of the adhesive composition can be further enhanced. From the above viewpoint, the content of the (meth)acrylic resin (A) is preferably 57.2 parts by mass or more and 94 parts by mass or less, and is preferably 62.5 parts by mass or more and 88.5 parts by mass or less. more preferred.

When the content of the (co)polymer (B) is 0.5 parts by mass or more, the adhesiveness of the adhesive composition can be further enhanced. When the content of the (co)polymer (B) is 50 parts by mass or less, the transparency of the adhesive composition can be further enhanced. From the above viewpoint, the content of the (co)polymer (B) is preferably 5 parts by mass or more and 40 parts by mass or less, more preferably 10 parts by mass or more and 35 parts by mass or less.

When the content of the cross-linking agent (C) is 0.5 parts by mass or more, the adhesive composition tends to agglomerate, and the adhesive composition remains on the surface of the adherend after pressure bonding, resulting in so-called adhesive residue. Hateful. When the content of the cross-linking agent (C) is 3 parts by mass or less, a larger amount of the (meth)acrylic resin (A) is contained in the adhesive composition, and the cross-linking density of the adhesive composition increases. Since the adhesive composition has a higher molecular weight and a higher molecular weight, it is less likely that the pressure-sensitive adhesive composition will follow the surface of the adherend during press-bonding, thereby reducing the pressure-sensitive adhesiveness. From the above viewpoint, the content of the cross-linking agent (C) is preferably 1 part by mass or more and 2.8 parts by mass or less, and more preferably 1.5 parts by mass or more and 2.5 parts by mass or less.

In addition, it is preferable that the adhesive composition regarding this embodiment does not substantially contain a rosin resin or a terpene resin. Rosin resins or terpene resins color or discolor the adhesive composition. Hydrogenated resins obtained by hydrogenating rosin resins or terpene resins are sometimes used in the adhesive composition in order to suppress the above-mentioned coloring, but these tend to reduce adhesive holding power. Furthermore, since the rosin resin or terpene resin has an acid value, the metal may be corroded when the adhesive composition containing these resins is applied to the metal.

Here, "substantially free" means that the content of the rosin resin or terpene resin is 0.1% by mass or less with respect to the total mass of the adhesive composition.

[Production method]
The adhesive composition according to the present embodiment contains the above-described (meth)acrylic resin (A), (co)polymer (B) and cross-linking agent (C) in an amount corresponding to the above-described content, optionally It can be prepared by mixing with the solvent used.

Examples of such solvents include ethyl acetate, butyl acetate, benzene, toluene, xylene, cyclohexane, methyl ethyl ketone, and the like.

[Use]
The adhesive composition according to the present embodiment can be used for various applications requiring adhesiveness as adhesive products such as tapes, labels, sheets and double-sided tapes.

Specifically, the adhesive processed product has a substrate layer and an adhesive layer, and the adhesive layer is made of the adhesive composition according to the present embodiment.

Although the thickness of the adhesive layer is not particularly limited, it is 5 μm or more and 50 μm or less from the viewpoint of imparting the desired adhesiveness to the adhesive processed product and reducing the impact on the productivity of the adhesive processed product. more preferably 5 μm or more and 40 μm or less, and even more preferably 10 μm or more and 30 μm or less.

The substrate is not particularly limited, but a transparent resin film is preferable when the adhesive processed product is used in applications requiring transparency.

Since the adhesive processed product has an adhesive layer made of the adhesive composition, it can have high transparency. For example, when the substrate is a transparent PET film, the adhesive processed product may have a total light transmittance of 87% or more as measured according to JIS K7361.

Since the adhesive processed product has an adhesive layer made of the adhesive composition, it can have high adhesiveness. For example, the adhesive processed product can be an adhesive processed product having an adhesive strength of 9 N/25 mm or more as measured by a 180° peel test using SUS as a J adherend.

The adhesive processed product can be produced by applying the adhesive composition to the surface of a substrate and drying the applied adhesive composition to crosslink each component.

The coating method is not particularly limited, and coating may be performed by a known method such as a roll coater method, a reverse roll coater method, a gravure roll method, a bar coater method, a comma coater method, and a die coater method. The drying conditions are also not particularly limited, and drying at 80 to 200° C. for 10 seconds to 10 minutes is preferable, and drying at 80 to 170° C. for 15 seconds to 5 minutes is more preferable.

EXAMPLES The present invention will be described below using examples and comparative examples, but the present invention is not limited to the following examples.

[Measurement of physical properties]
<Structural unit content>
The structural unit content (mol %) of (co)polymers (B1) to (co)polymers (B3) was determined by analysis of ¹³ C-NMR spectra measured under the following conditions.
Apparatus: Bruker Biospin AVANCE III cryo-500 type nuclear magnetic resonance apparatus Measurement nucleus: ¹³ C (125 MHz)
Measurement mode: Single pulse proton broadband decoupling Pulse width: 45° (5.00 μs)
Points: 64k
Measurement range: 250 ppm (-55 to 195 ppm)
Repeat time: 5.5 seconds Accumulation times: 128 times Measurement solvent: ortho-dichlorobenzene/benzene-d ₆ (4/1 (volume ratio))
Sample concentration: 60mg/0.6mL
Measurement temperature: 120°C
Window function: exponential (BF: 1.0 Hz)
Chemical shift standard: δδ signal 29.73 ppm

<Softening point>
The softening points of the (co)polymers (B1) to (co)polymers (B3) were measured by the ring and ball method according to JIS K2207.

<Glass transition temperature (Tg)>
The glass transition temperatures (Tg) of the (meth)acrylic resin (A) and the (co)polymers (B1) to (co)polymers (B3) were measured by enclosing these resins in a simple closed pan, under a stream of nitrogen, The DSC curve when the temperature was raised from −100° C. to 200° C. at a rate of 10° C./min was analyzed according to JIS K7121.

<Number average molecular weight (Mn), z average molecular weight (Mz), weight average molecular weight (Mw/Mn), and content of compounds having a molecular weight of 400 or less>
Number average molecular weight (Mn), weight average molecular weight (Mw), z average molecular weight (Mz) and molecular weight distribution of (meth)acrylic resin (A) and (co)polymer (B1) to (co)polymer (B3) (Mw/Mn) was obtained from GPC measurement. Measurement was performed under the following conditions. Then, the number average molecular weight (Mn), weight average molecular weight (Mw), and z average molecular weight (Mz) were obtained from a calibration curve using commercially available monodisperse standard polystyrene, and Mw/Mn was calculated. The content of compounds having a molecular weight of 400 or less was calculated by integrating the obtained molecular weight distribution.
Apparatus: GPC HLC-8320 (manufactured by Tosoh Corporation)
Solvent: Tetrahydrofuran Column: TSKgel G7000×1, TSKgel G4000×2, TSKgel G2000×1 (both manufactured by Tosoh Corporation)
Flow rate: 1.0 ml/min Sample: 20 mg/mL tetrahydrofuran solution Temperature: 40°C

[Synthesis of (meth)acrylic resin (A)]
A (meth)acrylic resin (A) was synthesized using the following monomers.

2-ethylhexyl acrylate (2EHA)
Ethyl acrylate (EA)
vinyl acetate (VA)
Acrylic acid (AA)
Hydroxyethyl acrylate (HEA)

(Synthesis of (meth)acrylic resin (A1))
A temperature-controllable reactor equipped with a stirrer was charged with 350 parts by mass of ethyl acetate as a polymerization solvent and 40 parts by mass of toluene, and the mixture was purged with nitrogen and heated. After heating to 75 ° C., 316 parts by weight of 2EHA, 43 parts by weight of EA, 50 parts by weight of VA, 9 parts by weight of AA, 2 parts by weight of HEA, and 2 parts by weight as a polymerization initiator were added to the reactor. A mixed solution of 1 part of benzoyl peroxide was continuously added and allowed to react for 5 hours. After 5 hours, the mixture was diluted with 120 parts by mass of toluene to obtain an ethyl acetate/toluene solution containing (meth)acrylic resin (A1) with a solid content of 45%.

The glass transition temperature (Tg) of the (meth)acrylic resin (A1) obtained by evaporating the solvent from the obtained solution was measured and found to be -60°C.

[Synthesis of (co)polymer (B)]
(Synthesis of (co)polymer (B1), (co)polymer (B4) and (co)polymer (B6))
A mixture of isopropenyl toluene, a _C5 fraction obtained by pyrolysis of petroleum naphtha and dehydrated toluene (sum of monomers/toluene = 1/1 ( (volume ratio)) and a boron trifluoride phenolate complex (1.7 equivalents of phenol) diluted 10 times with dehydrated toluene were continuously supplied to carry out a polymerization reaction at 5°C. The mass ratio of isopropenyltoluene to the _C5 fraction (isopropenyltoluene/ _C5 fraction) was 90/10, the feed rate of the mixture of monomer and toluene was 1.0 l/h, the feed rate of diluted catalyst was 105 ml/hour.

The reaction mixture was transferred to the second autoclave and allowed to continue the polymerization reaction at 5°C. Then, when the total residence time in the first and second autoclaves reached 2 hours, the reaction mixture was continuously discharged from the autoclave, and when the residence time reached 3 times, 1 liter of The reaction mixture was sampled to terminate the polymerization reaction. After the polymerization was completed, a 1 N NaOH aqueous solution was added to the sampled reaction mixture to deash the catalyst residue. Furthermore, after washing the obtained reaction mixture five times with a large amount of water, the solvent and unreacted monomers were distilled off under reduced pressure using an evaporator to obtain a copolymer of isopropenyl toluene/ _C5 fraction (co) A polymer (B4) was obtained. The (co)polymer (B4) has a content of structural units derived from isopropenyltoluene of 93 mol%, a softening point of 100°C, a glass transition temperature (Tg) of 50°C, and a number average molecular weight (Mn) of 700. , the z-average molecular weight (Mz) is 1500, the dispersity (Mw/Mn), which is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is 1.43, and the content of compounds having a molecular weight of 400 or less was 13%.

The (co)polymer (B4) was placed in a glass vessel attached to the top of a thin film distillation apparatus (DN60 type, manufactured by Asahi Seisakusho Co., Ltd.) and then heated to 200°C. After that, the solution was passed at 2 ml/min, concentrated at a rotation speed of 180 rpm and a vacuum degree of 0.02 Pa, and a glass eggplant flask attached to the bottom was used to obtain a copolymer of isopropenyl toluene and a _C5 fraction. ) Polymer (B1) was recovered. The (co)polymer (B1) has a structural unit content derived from isopropenyltoluene of 93 mol%, a softening point of 110°C, a glass transition temperature (Tg) of 65°C, and a number average molecular weight (Mn) of 850. , the z-average molecular weight (Mz) is 1600, the dispersity (Mw/Mn), which is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is 1.35, and the content of compounds having a molecular weight of 400 or less was 3%.

In addition, the low boiling point components were condensed with a condenser installed as a post-process of the thin-film distillation apparatus, and the (co)polymer (B6), which is a copolymer of isopropenyltoluene/ _C5 fraction, was recovered. The (co)polymer (B6) has a content of structural units derived from isopropenyltoluene of 93 mol%, a softening point not measured, a glass transition temperature (Tg) of −5° C., and a number average molecular weight (Mn) of is 380, the z-average molecular weight (Mz) is 400, the dispersity (Mw/Mn), which is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is 1.03, and the compound having a molecular weight of 400 or less The content was 62%.

(Synthesis of (co)polymer (B2))
Isopropenyl toluene and isopropenyl toluene were prepared in the same manner as in the synthesis of the (co)polymer (B4), except that the polymerization temperature in the first and second stages of the autoclave was 20° C. and the feed amount of the diluted catalyst was 50 ml/hour. A (co)polymer (B2), which is a copolymer of the _C5 fraction, was obtained. The (co)polymer (B2) has a content of structural units derived from isopropenyltoluene of 97 mol%, a softening point of 102°C, a glass transition temperature (Tg) of 65°C, and a number average molecular weight (Mn) of 850. , the z-average molecular weight (Mz) is 1650, the dispersity (Mw/Mn), which is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is 1.41, and the content of compounds having a molecular weight of 400 or less was 6%.

(Synthesis of (co)polymer (B3))
Except that the _C5 fraction obtained by pyrolysis of petroleum naphtha was not fed, the polymerization temperature in the first and second stages of the autoclave was 25 ° C., and the feed rate of the diluted catalyst was 30 ml / hour (common ) A (co)polymer (B3), which is a homopolymer of isopropenyltoluene, was obtained in the same manner as in the synthesis of the polymer (B4). The (co)polymer (B3) has a content of structural units derived from isopropenyltoluene of 100 mol%, a softening point of 102°C, a glass transition temperature (Tg) of 60°C, and a number average molecular weight (Mn) of 770. , the z-average molecular weight (Mz) is 1400, the dispersity (Mw/Mn), which is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is 1.31, and the content of compounds having a molecular weight of 400 or less was 7%.

(Synthesis of (co)polymer (B5))
A (co)polymer, which is a copolymer of isopropenyltoluene and a _C5 fraction, in the same manner as in the synthesis of (co)polymer (B4), except that the amount of diluted catalyst supplied was 90 ml/hour. (B5) was obtained. The (co)polymer (B5) has a content of structural units derived from isopropenyltoluene of 93 mol%, a softening point of 110°C, a glass transition temperature (Tg) of 70°C, and a number average molecular weight (Mn) of 900. , the z-average molecular weight (Mz) is 2400, the dispersity (Mw/Mn), which is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is 1.67, and the content of compounds having a molecular weight of 400 or less was 8%.

(Synthesis of (co)polymer (B7))
Instead of isopropenyl toluene and the _C5 fraction obtained by pyrolysis of petroleum naphtha, α-methylstyrene and styrene were fed in such an amount that the mass ratio (α-methylstyrene/styrene) was 60/40 and the autoclave Isopropenyltoluene alone was synthesized in the same manner as in the synthesis of the (co)polymer (B4), except that the polymerization temperature in the first and second stages was 7 ° C. and the feed rate of the diluted catalyst was 120 ml / hour. A (co)polymer (B7) was obtained as a polymer. The (co)polymer (B7) has a structural unit content derived from α-methylstyrene of 55 mol%, a softening point of 97° C., a glass transition temperature (Tg) of 55° C., and a number average molecular weight (Mn) of 840, the z-average molecular weight (Mz) is 3000, the dispersity (Mw/Mn), which is the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is 1.98, and the compound has a molecular weight of 400 or less. rate was 14%.

Composition, softening point, glass transition temperature (Tg), number average molecular weight (Mn), z average molecular weight (Mz), weight average molecular weight (Mw) of (co)polymer (B1) to (co)polymer (B7) ) to the number average molecular weight (Mn), and the content of compounds having a molecular weight of 400 or less are shown in Table 1. In Table 1, "IPT" represents isopropenyltoluene.

[Crosslinking agent (C)]
As the cross-linking agent (C1), Takenate D-101E manufactured by Mitsui Chemicals, Inc. (an isocyanate-based compound, “Takenate” is a registered trademark of the same company) was used.

[Preparation and Evaluation of Adhesive Processed Goods]
An ethyl acetate/toluene solution containing the (meth)acrylic resin (A1), any one of the (co)polymers (B1) to (co)polymers (B7), and a cross-linking agent (C) in a solution. The ratio of the (meth)acrylic resin (A1) and (co)polymer (B1) to (co)polymer (B3) contained in the cross-linking agent (C) to the mass ratio shown in Table 2 were mixed at room temperature to obtain an ethyl acetate/toluene solution of the adhesive composition.

The resulting ethyl acetate/toluene solution of the adhesive composition was applied to a release paper so that the film thickness after drying was 10 to 50 μm, dried at 100° C. for 10 minutes, and then a 25 μm PET film was applied to the coated surface. A pressure-sensitive adhesive sheet was produced by pressure bonding. The pressure-sensitive adhesive composition was sufficiently crosslinked by allowing it to stand at 50°C for 3 days.

<Measurement of total light transmittance>
The release paper of the adhesive sheet having an adhesive layer with a thickness of 50 μm was peeled off to expose the adhesive layer, and a PET film with a thickness of 25 μm was pressed against the exposed adhesive layer to obtain a test piece. The configuration of the test piece is PET film/adhesive layer/PET film=25/50/25μ. After that, the total light transmittance of the test piece was measured according to JIS K7361.

<Measurement of adhesive strength>
The adhesive sheet having an adhesive layer with a film thickness of 15 μm or 30 μm was cut into a width of 25 mm and a length of 150 mm to obtain a test piece. The release paper of the test piece is peeled off to expose the adhesive layer, the exposed adhesive layer is brought into contact with a stainless steel plate (SUS) in an atmosphere of 23 ° C., and a 2 kg mass rubber roll is reciprocated twice to perform the test. The pieces were crimped. After being left for 20 minutes, the 180° peel strength was measured at a speed of 300 mm/min according to JIS Z0237.

Tables 2 and 3 show the formulation of the adhesive composition constituting the produced adhesive processed product, and the total light transmittance and adhesive strength of the adhesive processed product.

FIG. 1 shows the relationship between the total light transmittance and the adhesive force when the thickness of the adhesive layer is 15 μm in Examples 1 to 5 and Comparative Examples 1 to 9.

As is clear from Tables 2, 3 and FIG. 1, the adhesiveness containing the (co)polymer is higher than the adhesive composition containing no (co)polymer containing a structural unit derived from isopropenyltoluene. The composition had higher adhesion. In addition, the adhesive composition containing a (co)polymer that satisfies all of the requirements (B-1) to (B-5) does not satisfy any of the requirements (B-1) to (B-5) ( Both adhesion and transparency were higher than the adhesive composition containing the co)polymer.

This application is an application claiming priority based on Japanese Application No. 2019-117570 filed on June 25, 2019, and the contents described in the claims, specification and drawings of the application are herein incorporated in the application.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition with both high transparency and adhesiveness is provided. INDUSTRIAL APPLICABILITY The present invention can be suitably practiced in various applications that particularly require transparency of the adhesive composition.

Claims (6)

47 parts by mass or more and 99 parts by mass or less (meth)acrylic resin (A), 0.5 parts by mass or more and 50 parts by mass or less of (co)polymer (B) different from (meth)acrylic resin (A), and , containing 0.5 parts by mass or more and 3 parts by mass or less of the cross-linking agent (C) (however, the content of the (meth) acrylic resin (A), the (co) polymer (B) and the cross-linking agent (C) The total is 100 parts by mass.),
The (meth)acrylic resin (A) satisfies the following (A-1) and (A-2), and
The (co)polymer (B) satisfies all of the following (B-1) to (B-5),
Adhesive composition.
(A-1) It contains a structural unit derived from a (meth)acrylate having an alkyl group having 1 to 12 carbon atoms and a structural unit derived from a (meth)acrylate containing a hydroxyl group.
(A-2) The glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) is in the range of -80°C or higher and 0°C or lower.
(B-1) Containing structural units derived from isopropenyltoluene in an amount of 20 mol % or more based on the total amount of the structural units.
(B-2) The softening point measured according to JIS K2207 is in the range of 90°C or higher and 130°C or lower.
(B-3) The glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) is in the range of 40°C or higher and 80°C or lower.
(B-4) The content of compounds having a molecular weight of 400 or less in terms of polystyrene measured by gel permeation chromatography (GPC) is 10% by mass or less.
(B-5) The polystyrene-equivalent number-average molecular weight (Mn) measured by gel permeation chromatography (GPC) is in the range of 750 or more and 1000 or less, and the z-average molecular weight (Mz) is in the range of 1200 or more and 2000 or less. and the dispersity (Mw/Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is 1.5 or less. The adhesive composition according to claim 1, wherein the (co)polymer (B) satisfies the following (B-6).
(B-6) Consisting of styrene, α-methylstyrene, indene, vinyltoluene, and an unsaturated aliphatic hydrocarbon compound having 4 or 5 carbon atoms in an amount of 1 mol% or more and 80 mol% or less of the total amount of the structural units It contains structural units derived from monomers selected from the group. 3. An adhesive processed product obtained by processing the adhesive composition according to claim 1 or 2, which is a tape, label, sheet or double-sided tape. The adhesive processed product according to claim 3, having an adhesive layer with a thickness of 5 µm or more and 50 µm or less. 5. The adhesive processed product according to claim 3 or 4, having a total light transmittance of 87% or more as measured according to JIS K7361. The adhesive processed product according to any one of claims 3 to 5, wherein the adhesive strength measured by a 180° peel test using SUS as an adherend is 9 N/25 mm or more.

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