CN114051521A

CN114051521A - Adhesive sheet and use thereof

Info

Publication number: CN114051521A
Application number: CN202080047095.6A
Authority: CN
Inventors: 西丸步; 形见普史; 野中崇弘
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2019-06-28
Filing date: 2020-06-23
Publication date: 2022-02-15
Also published as: WO2020262340A1; KR20220024977A

Abstract

Provided is an adhesive sheet having an adhesive layer. The adhesive sheetHas the following characteristics (a) and (b). (a) An elastic modulus measured by a tensile test is 3.0MPa or more. (b) The impact resistance measured by the shear impact test was 2.0J/(10mm)²The above.

Description

Adhesive sheet and use thereof

Technical Field

The invention relates to an adhesive sheet, a film member with the adhesive sheet and a method for manufacturing a laminated body.

The present application claims priority based on japanese patent application No. 2019-122284, filed on 28.6.2019, and japanese patent application No. 2020-107125, filed on 22.6.2020, the entire contents of which are incorporated herein by reference.

Background

Generally, adhesives (also referred to as pressure sensitive adhesives the same applies hereinafter) have the following properties: the adhesive exhibits a soft solid (viscoelastic body) state in a temperature range around room temperature, and easily adheres to an adherend under pressure. Such properties are sufficiently exhibited, and adhesives are typically used in various fields in the form of pressure-sensitive adhesive sheets including an adhesive layer. Patent document 1 is an example of a technical document relating to an adhesive sheet.

Documents of the prior art

Patent document

Patent document 1: japanese patent application laid-open No. 2016-017113

Disclosure of Invention

Problems to be solved by the invention

Various properties are required for the adhesive depending on the use. Of these properties, it is sometimes difficult to achieve a high level of balance, for example, when one property is improved, another property tends to be lowered. Examples of the characteristics that are in such a relationship that they are difficult to satisfy include a property of being hardly deformed against stress (hereinafter, also referred to as "deformation resistance") and a property of withstanding impact and maintaining the bond with the adherend (hereinafter, also referred to as "impact resistance").

Accordingly, an object of the present invention is to provide a pressure-sensitive adhesive sheet capable of forming a joint having high deformation resistance and high impact resistance. Another object of the present invention is to provide a film member with an adhesive sheet, which comprises the adhesive sheet. Another object of the present invention is to provide a method for producing a laminate using the adhesive sheet.

According to the specification, there is provided an adhesive sheet comprising an adhesive layer and having the following characteristics (a) and (b).

(a) The elastic modulus measured by the following tensile test is 3.0MPa or more.

(b) The impact resistance measured by the following shear impact test was 2.0J/(10mm)²The above.

[ tensile test ]

Under the illumination of 300mW/cm²And a cumulative light amount of 3000mJ/cm²The pressure-sensitive adhesive layer was irradiated with ultraviolet rays under the conditions of (1) and cured at 50 ℃ for 48 hours, and then the pressure-sensitive adhesive layer was cut into a size of 10mm in width and 150mm in length to prepare a test piece. The tensile test of the test piece was carried out under an environment of 23 ℃ and 50% RH at a chuck pitch of 120mm and a tensile speed of 50 mm/min using a tensile tester to obtain a stress-displacement curve (hereinafter, also referred to as "S-S curve"), and the elastic modulus [ MPa ] was calculated from the initial slope thereof](hereinafter also referred to as tensile modulus).

[ shear impact test ]

The shear impact test was carried out using a pendulum type bonding shear impact tester according to JIS K6855. As the measurement samples, the following samples were used: after a first surface of the adhesive layer of 10mm square was bonded to the center of a chemically strengthened glass plate of 25mm square and 1.7mm thickness, a second surface of the adhesive layer was bonded to the center of a stainless steel plate of 40mm square (SUS304BA plate) and pressure-bonded under a load of 5N for 10 seconds, and then autoclave treatment (50 ℃, 0.5MPa, 15 minutes) was carried out at an illuminance of 300mW/cm²And a cumulative light amount of 3000mJ/cm²Under the condition of irradiating from the side of the glass plateAfter the UV irradiation, the sample was aged at 50 ℃ for 48 hours.

The measurement sample was fixed so that the lower side of the stainless steel plate was positioned, and the absorption energy [ J ] when the outer peripheral side surface of the glass plate was subjected to hammering under conditions of hammering energy of 2.75J and hammering speed (impact speed) of 3.5 m/sec was measured in an environment of 23 ℃ and 50% RH]Thus, the impact resistance [ J/(10mm)²]。

By satisfying the above property (a), the pressure-sensitive adhesive layer can exhibit high deformation resistance in a use state of the pressure-sensitive adhesive sheet, for example. The pressure-sensitive adhesive sheet satisfying the above characteristics (a) and (b) can be suitably used for the purpose of, for example, joining or fixing members because it can form a joint having high deformation resistance and high impact resistance.

Further, according to the specification, there is provided an adhesive sheet comprising an adhesive layer containing a polymer (a) and a photoreactive monomer (B). In some embodiments of the above adhesive sheet, the photoreactive monomer (B) includes a compound B1 having a cyclic structure and 2 or more ethylenically unsaturated groups in a molecule. The average molecular weight of the compound B1 per the ethylenically unsaturated group is preferably 100g/mol or more. According to the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer, a joint having high deformation resistance and high impact resistance can be suitably formed.

The adhesive sheet of any embodiment disclosed herein may satisfy the following characteristic (c). The adhesive sheet satisfying the property (c) can be suitably used for the purpose of, for example, joining, fixing, etc. of members.

(c) The peel strength measured by the following peel test is 1.0N/10mm or more.

[ peeling test ]

The first surface of the pressure-sensitive adhesive layer was pressure-bonded to a glass plate by reciprocating a 2kg rubber roller once, and after autoclave treatment (50 ℃, 0.5MPa, 15 minutes), the illuminance was 300mW/cm²And a cumulative light amount of 3000mJ/cm²Under the conditions (3) described above, ultraviolet rays were irradiated from the glass plate side. Aging at 50 deg.C for 48 hr, and placing at 23 deg.C and 50% RH, using tensile tester at peel angle of 180 deg.C and tensile speed of 60 mm/minThe peel strength of the test piece when peeled from the glass plate was measured under the conditions of (1).

According to the specification, there is provided a film member with an adhesive sheet, comprising: any of the pressure-sensitive adhesive sheets disclosed herein, and a film member bonded to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet. According to the film member with an adhesive sheet, a joint having high deformation resistance and high impact resistance can be suitably formed.

According to this specification, there is provided a laminate manufacturing method comprising, in order: the pressure-sensitive adhesive sheet disclosed herein is bonded to an adherend, and the pressure-sensitive adhesive layer is photocured by irradiating the pressure-sensitive adhesive sheet with ultraviolet light. According to the above method, a laminate having both impact resistance and high deformation resistance can be produced.

It should be noted that an embodiment obtained by appropriately combining the above-described elements may be included in the scope of the invention for which patent protection is sought by the present patent application.

Drawings

Fig. 1 is a sectional view schematically showing the structure of an adhesive sheet according to an embodiment.

Fig. 2 is a sectional view schematically showing the configuration of an adhesive sheet of another embodiment.

Fig. 3 is a cross-sectional view schematically showing a film member with an adhesive sheet in which the adhesive sheet of one embodiment is attached to the film member.

Detailed Description

Preferred embodiments of the present invention will be described below. It is to be noted that matters necessary for carrying out the present invention other than the ones specifically mentioned in the present specification can be understood by those skilled in the art based on the teaching about the implementation of the invention described in the present specification and the technical common sense at the time of application. The present invention can be implemented based on the contents disclosed in the present specification and the common technical knowledge in the field. In the following drawings, members and portions that exhibit the same functions are sometimes described with the same reference numerals, and redundant description may be omitted or simplified. In addition, the embodiments described in the drawings are illustrated for clarity of explanation of the present invention, and do not necessarily accurately represent the size or scale of a product actually provided.

In the present specification, "acrylic polymer" refers to a polymer derived from a monomer component containing an acrylic monomer in an amount of more than 50% by weight, and also refers to an acrylic polymer. The acrylic monomer is a monomer having at least 1 (meth) acryloyl group in 1 molecule. In the present specification, "(meth) acryloyl group" refers to acryloyl and methacryloyl groups in a general manner. Similarly, "(meth) acrylate" refers generically to acrylate and methacrylate, and "(meth) acrylic acid" refers generically to acrylic acid and methacrylic acid, respectively.

In this specification, "mass" and "weight" have the same meaning.

In this specification, "photoreactive monomer" is a compound having at least 1 functional group capable of undergoing a reaction thereof by irradiation with light (photoreactive functional group) in a molecule, and typically a compound having at least 1 ethylenically unsaturated group as the photoreactive functional group in a molecule. The photoreactive monomer referred to herein may be any monomer as long as it can react as a monomer, and may be a polymer such as an oligomer or a polymer (for example, a polymer having at least 1 ethylenically unsaturated group in the molecule).

< example of adhesive sheet construction >

Fig. 1 shows an example of the structure of the pressure-sensitive adhesive sheet disclosed herein. The adhesive sheet 1 is configured as a single-sided adhesive sheet (support-attached single-sided adhesive sheet) including: one surface 10A is a pressure-sensitive adhesive layer 10 which is a bonding surface (pressure-sensitive adhesive surface) on an adherend, and a support 20 which is laminated on the other surface 10B of the pressure-sensitive adhesive layer 10. The adhesive layer 10 is joined to one surface 20A of the support 20. As the support 20, a resin film such as a polyester film can be used, for example. The support 20 may be an optical film such as a polarizing plate. In the example shown in fig. 1, the adhesive layer 10 has a single-layer structure. The psa sheet 1 before use (before being adhered to an adherend) may be, for example, in the form of a release-liner-equipped psa sheet 50 having a psa surface 10A protected by a release liner 30 having a releasable surface (release surface) on at least the psa layer side as shown in fig. 1. Alternatively, the following embodiments are possible: the second surface 20B (the surface opposite to the first surface 20A, also referred to as the back surface) of the support 20 is a release surface, and the adhesive surface 10A is protected by winding or laminating the adhesive surface 10A so as to be in contact with the second surface 20B of the support 20.

The release liner is not particularly limited, and for example, the following can be used: release liners in which the surface of a liner base material such as a resin film or paper is subjected to a release treatment; and release liners made of low-adhesion materials such as fluorine-based polymers (e.g., polytetrafluoroethylene) and polyolefin-based resins (e.g., polyethylene and polypropylene). In the above-mentioned peeling treatment, for example, a silicone-based peeling treatment agent, a long chain alkyl-based peeling treatment agent, or the like can be used. In some modes, it may be preferable to use a resin film subjected to a release treatment as a release liner.

The adhesive sheet disclosed herein may be a support-less double-sided adhesive sheet comprising an adhesive layer. As shown in fig. 2, the unsupported double-sided pressure-sensitive adhesive sheet 2 may be in a form in which the

respective surfaces

10A and 10B of the pressure-sensitive adhesive layer 10 are protected by

release liners

31 and 32 having a releasable surface (release surface) on at least the pressure-sensitive adhesive layer side before use. Alternatively, the following embodiments are possible: the back surface (surface on the opposite side to the pressure-sensitive adhesive side) of the release liner 31 is a release surface, and the pressure-

sensitive adhesive surfaces

10A and 10B are protected by winding or laminating the release liner 31 so that the pressure-sensitive adhesive surface 10B comes into contact with the back surface. Such a double-sided adhesive sheet without a support can be used, for example, by bonding a support to either surface of an adhesive layer.

The pressure-sensitive adhesive sheet disclosed herein may be in the form of a double-sided pressure-sensitive adhesive sheet with a support, in which pressure-sensitive adhesive layers are laminated on one surface and the other surface of a sheet-like support. The support in the pressure-sensitive adhesive sheet of the above embodiment may be, for example, a resin film such as a polyester film, or an optical film such as a polarizing plate.

The adhesive sheet disclosed herein may be a component of a film member with an adhesive sheet in which a film member is joined to one surface of an adhesive layer. For example, as shown in fig. 3, the adhesive sheet 1 shown in fig. 1 may be a component of a film member with an adhesive sheet 100 in which a film member 70 is joined to one surface 10A of an adhesive layer 10. The film member may be, for example, an electromagnetic wave transmitting metallic luster member, a polarizing plate, or another optical film as described in Japanese patent application laid-open No. 2018-69462.

< characteristics of pressure-sensitive adhesive sheet >

(tensile modulus)

In the psa sheet disclosed herein, the tensile modulus of the psa layer (which may be formed using any of the psa compositions disclosed herein) is preferably 3.0MPa or greater. The tensile modulus can be measured by the tensile test described above, and more specifically, can be measured by the method described in the examples described below. Adhesive layers with higher tensile modulus tend to exhibit better resistance to deformation. The pressure-sensitive adhesive sheet having a high tensile modulus can be suitably used for the purpose of, for example, joining or fixing members. For example, in a laminate in which a member and an adherend are joined together via a pressure-sensitive adhesive layer, when the pressure-sensitive adhesive layer has high deformation resistance, it is possible to contribute to maintaining the relative position of the member with respect to the adherend with high accuracy. In addition, for example, in a laminate in which a film member and an adherend are joined together via a pressure-sensitive adhesive layer, when the pressure-sensitive adhesive layer has high deformation resistance, it is possible to contribute to suppressing a phenomenon in which the laminate is locally pressed from the film member side and the appearance of the laminate is changed. In the case where the adherend is a laminate of a rigid member having transparency (e.g., a glass member), it is particularly significant to suppress a change in appearance when viewed from the adherend side.

In the psa sheet according to some preferred embodiments, the tensile modulus may be, for example, 5.0MPa or more, 7.0MPa or more, 10.0MPa or more, 15.0MPa or more, and 20.0MPa or more. By increasing the tensile modulus, the deformation resistance tends to be improved. The upper limit of the tensile modulus is not particularly limited. From the viewpoint of easily obtaining balance with other characteristics (for example, one or two or more characteristics selected from the group consisting of impact resistance, peel strength, haze value, and the like), the tensile modulus is usually favorably 150MPa or less, preferably 120MPa or less, may be 100MPa or less, may be 80MPa or less, and may be 60MPa or less. The tensile modulus can be adjusted by selecting the composition of the adhesive layer, and the like.

In the tensile test, the treatment of irradiating the pressure-sensitive adhesive layer with ultraviolet rays is preferably performed in a state where the pressure-sensitive adhesive layer is sandwiched between transparent release liners. As the release liner, a polyester resin film (for example, a polyethylene terephthalate resin (PET) film) having at least one side thereof subjected to a release treatment can be preferably used from the viewpoint of transparency. The thickness of the release liner is not particularly limited, but may be, for example, about 10 μm to 125 μm, 10 μm to 75 μm, or 20 μm to 50 μm.

The thickness of the test piece used in the tensile test may be the same as or different from the thickness of the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet disclosed herein. For example, when the thickness of the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet is relatively small, the tensile modulus of the pressure-sensitive adhesive layer can be determined as a result of the tensile test using a test piece prepared to have a thickness of 5 μm or more (for example, about 5 μm to 200 μm) for the purpose of improving workability or the like. The thickness of the test piece can be adjusted by, for example, appropriately overlapping the adhesive layer before ultraviolet irradiation. As the tensile modulus of the pressure-sensitive adhesive layer, a test piece having a thickness that facilitates a tensile test can be prepared by using the same pressure-sensitive adhesive composition as that used for forming the pressure-sensitive adhesive layer to be measured, and the test piece can be subjected to the tensile test. The tensile test can be performed using, for example, a test piece having a thickness of about 10 to 50 μm (preferably about 15 to 25 μm).

(impact resistance)

The impact resistance of the adhesive sheet disclosed herein is preferably 2.0J/(10mm)²The above. The impact resistance is measured by the shear impact test described above, and more specifically, can be measured by the following testMeasured by the method described in the examples. The pressure-sensitive adhesive sheet having high impact resistance can form a highly reliable bond. This may be an advantageous feature of an adhesive sheet, for example, for joining, fixing, etc. of members. The pressure-sensitive adhesive sheet can withstand an impact caused by, for example, dropping, impact, or the like, and can satisfactorily maintain the bonding of a member to an adherend.

In some preferred embodiments of the pressure-sensitive adhesive sheet, the impact resistance may be, for example, 2.1J/(10mm)²Above, it can be 2.3J/(10mm)²Above, it can be 2.5J/(10mm)²Above, it can be 2.7J/(10mm)²Above, it can be 3.0J/(10mm)²The above. The pressure-sensitive adhesive sheet disclosed herein preferably has an impact resistance of 3.3J/(10mm)²Above or 3.5J/(10mm)²The above is implemented. The upper limit of the impact resistance is not particularly limited. From the viewpoint of easily obtaining balance with other characteristics, the impact resistance may be, for example, 20J/(10mm)²Hereinafter, it may be 15J/(10mm)²Hereinafter, it may be 10J/(10mm)²Hereinafter, it may be 8.0J/(10mm)²And can be 6.0J/(10mm)²The following. The impact resistance can be adjusted by selecting the composition, thickness, etc. of the adhesive layer.

The pressure-sensitive adhesive sheet disclosed in the present specification includes a form without limitation to the tensile modulus, and in such a form, the pressure-sensitive adhesive sheet is not limited to one satisfying the tensile modulus. Similarly, the pressure-sensitive adhesive sheet disclosed in the present specification includes a form in which the impact resistance is not limited, and in such a form, the pressure-sensitive adhesive sheet is not limited to one satisfying the above impact resistance.

(Peel Strength)

The peel strength of the pressure-sensitive adhesive sheet disclosed herein is not particularly limited, and may be set according to the purpose. The peel strength can be measured by the above peel test, and more specifically, can be measured by the method described in the examples described later. In some embodiments, the peel strength may be, for example, 0.5N/10mm or more, and from the viewpoint of bonding reliability, is preferably 1.0N/10mm or more, more preferably 1.5N/10mm or more, may be 2.0N/10mm or more, may be 2.2N/10mm or more, and may be 2.3N/10mm or more. In addition, from the viewpoint of easily obtaining balance with other characteristics, the peel strength may be, for example, 10N/10mm or less, 8.0N/10mm or less, 6.0N/10mm or less, 5.0N/10mm or less, and 4.0N/10mm or less. The peel strength can be adjusted by selecting the composition, thickness, etc. of the adhesive layer.

(haze value)

In the adhesive sheet disclosed herein, the haze value of the adhesive layer is not particularly limited. When transparency is required for the pressure-sensitive adhesive layer, the haze value of the pressure-sensitive adhesive layer may be, for example, 10% or less, 5.0% or less, 3.0% or less, or 1.0% or less. As a non-limiting example of the use mode in which transparency is required for the pressure-sensitive adhesive layer, there can be mentioned a use mode in which a member is joined to an adherend having transparency through the pressure-sensitive adhesive layer, and the member is recognized from the adherend side through the pressure-sensitive adhesive layer; and a use mode in which a pressure-sensitive adhesive sheet having a support is joined to an adherend having transparency, and the support is recognized from the adherend side through the pressure-sensitive adhesive layer. In some embodiments, the haze value of the adhesive layer may be less than 1.0%, may be less than 0.7%, and may be 0.5% or less (e.g., 0 to 0.5%).

The "haze value" herein refers to a ratio of diffuse transmitted light to total transmitted light when the measurement object is irradiated with visible light. Also known as haze. The haze value may be represented by the following formula.

Th[％]＝Td/Tt×100

In the above formula, Th is a haze value [% ], Td is a scattered light transmittance, and Tt is a total light transmittance.

The haze value can be determined by: under the illumination of 300mW/cm²And a cumulative light amount of 3000mJ/cm²The pressure-sensitive adhesive layer was cured at 50 ℃ for 48 hours under irradiation with ultraviolet rays, and the measurement was carried out using a haze meter (for example, "MR-100" manufactured by Cumura color technology research). The haze value can be adjusted, for example, by selecting the composition, thickness, etc. of the adhesive layer. The adhesive layer is irradiated with lightThe ultraviolet ray treatment is preferably performed in a state where the pressure-sensitive adhesive layer is sandwiched between transparent release liners (for example, release-treated PET films) as in the tensile test in the tensile modulus measurement.

< adhesive layer >

The adhesive sheet in the technology disclosed herein (including the adhesive sheet, the adhesive sheet-attached film member, and the laminate manufacturing method, the same applies hereinafter) includes an adhesive layer. The composition of the pressure-sensitive adhesive layer can be selected so that a joint having high deformation resistance and high impact resistance can be formed.

(Polymer (A))

In some embodiments, the adhesive layer contains a polymer (a). Examples of the material that can be used as the polymer (a) include polymers that exhibit rubber elasticity in a room temperature region, such as acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluorine polymers, which are known in the field of adhesives. These may be used alone in 1 kind or in combination of 2 or more kinds.

The weight ratio of the polymer (a) to the entire weight of the pressure-sensitive adhesive layer is usually preferably 40% by weight or more, preferably 50% by weight or more, may be 60% by weight or more, and may be 70% by weight or more, from the viewpoint of impact resistance and the like. The weight ratio of the polymer (a) to the entire weight of the pressure-sensitive adhesive layer is typically less than 100% by weight, and is usually 95% by weight or less, preferably 92% by weight or less, may be 90% by weight or less, and may be 87% by weight or less, which is advantageous from the viewpoint of easy balance of the adjustment properties.

As a preferred example of the polymer (a), an acrylic polymer is mentioned. The adhesive layer in the technology disclosed herein may be an acrylic adhesive layer containing an acrylic polymer as a base polymer (a main component in the polymer component, that is, a component occupying more than 50% by weight). The acrylic polymer (hereinafter sometimes referred to as "acrylic polymer (a)") as the polymer (a) is preferably 40-fold in weightAn acrylic polymer comprising a monomer component containing an alkyl (meth) acrylate having a linear or branched alkyl group having 1 to 20 carbon atoms at the ester end in a proportion of at least% by weight. Hereinafter, an alkyl (meth) acrylate having an alkyl group having not less than X and not more than Y carbon atoms at the ester end may be referred to as "C (meth) acrylate_X-YAlkyl ester ".

In some embodiments, (meth) acrylic acid C in the entirety of the monomer component of the acrylic polymer (A)_1-20The proportion of the alkyl ester is preferably more than 40% by weight from the viewpoint of the balance of easily obtainable characteristics, and may be, for example, 45% by weight or more, 50% by weight or more, 55% by weight or more, and 60% by weight or more. (meth) acrylic acid C in monomer component_1-20The proportion of the alkyl ester may be 100% by weight, but is usually preferably 98% by weight or less, for example, 95% by weight or less, and may be 90% by weight or less, from the viewpoint of balance of easily obtainable characteristics. In some embodiments, the amount of (meth) acrylic acid C in the entire monomer component of the acrylic polymer (A) is_1-20The proportion of the alkyl ester may be, for example, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, and 60% by weight or less, from the viewpoint of improving the aggregation property of the pressure-sensitive adhesive layer.

As (meth) acrylic acid C_1-20Non-limiting specific examples of the alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylateDodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, and the like.

Among them, it is preferable to use at least (meth) acrylic acid C_4-20Alkyl esters, more preferably at least (meth) acrylic acid C_4-18An alkyl ester. (meth) acrylic acid C is particularly preferred_4-18As the alkyl ester, n-Butyl Acrylate (BA) and 2-ethylhexyl acrylate (2EHA) are listed. (meth) acrylic acid C which can be preferably used_4-20Other specific examples of the alkyl ester include isononyl acrylate, n-Butyl Methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA), isostearyl acrylate (iSTA) and the like. These (meth) acrylic acids C_4-20The alkyl ester may be used alone in 1 kind or in combination of 2 or more kinds.

The monomer component preferably contains, for example, either or both of n-Butyl Acrylate (BA) and 2-ethylhexyl acrylate (2 EHA). In some embodiments, the monomer component preferably contains at least BA. Here, examples of the monomer component containing at least BA include: a monomeric component comprising BA but not comprising 2 EHA; comprises BA and 2EHA, the 2EHA content being less than the BA content (for example, the 2EHA content is less than 0.5 times or less than 0.3 times the BA content).

In some embodiments, the monomer component constituting the acrylic polymer (a) may contain (meth) acrylic acid C in a proportion of 40% by weight or more_4-18An alkyl ester. (meth) acrylic acid C in the monomer component_4-18The proportion of the alkyl ester may be, for example, 50% by weight or more, 60% by weight or more, and 65% by weight or more.

Further, from the viewpoint of improving the aggregation property of the pressure-sensitive adhesive layer, (meth) acrylic acid C_4-18The proportion of the alkyl ester in the monomer component is usually preferably 99.5% by weight or less, and may be 95% by weight or less, and may beThe content is 85% by weight or less, and may be 75% by weight or less.

The monomer component constituting the acrylic polymer (a) may contain an alkyl (meth) acrylate and, if necessary, another monomer (copolymerizable monomer) copolymerizable with the alkyl (meth) acrylate. As the copolymerizable monomer, a monomer having a polar group (e.g., a carboxyl group, a hydroxyl group, a nitrogen atom-containing ring, etc.) or a monomer having a high glass transition temperature of a homopolymer (e.g., 10 ℃ or higher) can be preferably used. The monomer having a polar group may contribute to introduction of a crosslinking point in the acrylic polymer (a) or increase the cohesive force of the adhesive. The copolymerizable monomer may be used alone in 1 kind or in combination of 2 or more kinds.

Specific non-limiting examples of the copolymerizable monomer include the following monomers.

Carboxyl group-containing monomer: for example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like.

Acid anhydride group-containing monomer: for example maleic anhydride, itaconic anhydride.

Hydroxyl group-containing monomer: for example, hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate.

Sulfonic acid group-or phosphoric acid group-containing monomer: for example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2- (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid, 2-hydroxyethylacryloyl phosphate, and the like.

Epoxy group-containing monomer: examples of the epoxy group-containing acrylate include glycidyl (meth) acrylate, 2-ethyl glycidyl (meth) acrylate, allyl glycidyl ether, and glycidyl (meth) acrylate.

A cyano group-containing monomer: for example, acrylonitrile, methacrylonitrile, and the like.

Isocyanate group-containing monomer: for example, 2-isocyanatoethyl (meth) acrylate and the like.

Amide group-containing monomer: for example, (meth) acrylamide; n, N-dialkyl (meth) acrylamides such as N, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-dipropyl (meth) acrylamide, N-diisopropyl (meth) acrylamide, N-di (N-butyl) (meth) acrylamide, and N, N-di (tert-butyl) (meth) acrylamide; n-alkyl (meth) acrylamides such as N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, and N-N-butyl (meth) acrylamide; n-vinylcarboxylic acid amides such as N-vinylacetamide; monomers having a hydroxyl group and an amide group, for example, N-hydroxyalkyl (meth) acrylamides such as N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, N- (1-hydroxypropyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, N- (2-hydroxybutyl) (meth) acrylamide, N- (3-hydroxybutyl) (meth) acrylamide, and N- (4-hydroxybutyl) (meth) acrylamide; monomers having an alkoxy group and an amide group, for example, N-alkoxyalkyl (meth) acrylamides such as N-methoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, and N-butoxymethyl (meth) acrylamide; and N, N-dimethylaminopropyl (meth) acrylamide, N- (meth) acryloylmorpholine, and the like.

Amino group-containing monomers: for example, aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, tert-butylaminoethyl (meth) acrylate.

Monomer having epoxy group: for example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether.

Monomer having nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N- (meth) acryloyl-2-pyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N- (meth) acryloylmorpholine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1, 3-oxazin-2-one, N-vinyl-2-pyrrolidone, N-vinyl-pyrrolidone, N-vinyl-2-pyrrolidone, N-vinyl-2-vinyl-pyrrolidone, N-vinyl-pyrrolidone, N-vinyl-imidazole, N-vinyl-oxazole, N-2-pyrrolidone, N-vinyl-pyrrolidone, N-vinyl-2-pyrrolidone, N-vinyl-2-vinyl-pyrrolidone, N-vinyl-pyrrolidone, N-vinyl-2-pyrrolidone, N-vinyl-2-vinyl-pyrrolidone, N-vinyl-pyrrolidone, N-vinyl-2-vinyl-pyrrolidone, N-vinyl-pyrrolidone, and N-pyrrolidone, N-2-vinyl-pyrrolidone, and N-vinyl-N-vinyl-pyrrolidone, and N-vinyl-N-vinyl-N-pyrrolidone, N-vinyl-N-vinyl-2-N-vinyl-N-vinyl-N-vinyl-2-vinyl-N-vinyl-pyrrolidone, N-, N-vinyl-3, 5-morpholine-dione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N-vinylpyridazine and the like (for example, lactams such as N-vinyl-2-caprolactam).

Monomer having succinimide skeleton: for example, N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyhexamethylene succinimide, and the like.

Maleimide group: for example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and the like.

Itaconimides: for example, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-lauryl itaconimide, etc.

Aminoalkyl (meth) acrylates: for example, aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, N-diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate.

Alkoxy group-containing monomers: alkoxyalkyl (meth) acrylates (alkoxyalkyl (meth) acrylates) such as 2-methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, and ethoxypropyl (meth) acrylate; alkoxyalkylene glycol (meth) acrylates (for example, alkoxypolyalkylene glycol (meth) acrylates) such as methoxy ethylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, and methoxy polypropylene glycol (meth) acrylate.

Alkoxysilyl group-containing monomer: examples thereof include alkoxysilyl group-containing (meth) acrylates such as 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane and 3- (meth) acryloyloxypropylmethyldiethoxysilane, and alkoxysilyl group-containing vinyl compounds such as vinyltrimethoxysilane and vinyltriethoxysilane.

Vinyl esters: for example, vinyl acetate, vinyl propionate, and the like.

Vinyl ethers: for example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

Aromatic vinyl compound: for example, styrene, alpha-toluylene, vinyl toluene, and the like.

Olefins: for example, ethylene, butadiene, isoprene, isobutylene, and the like.

(meth) acrylate having alicyclic hydrocarbon group: examples of the (meth) acrylic acid ester include alicyclic hydrocarbon group-containing (meth) acrylic acid esters such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and adamantyl (meth) acrylate.

(meth) acrylate having an aromatic hydrocarbon group: for example, aromatic hydrocarbon group-containing (meth) acrylates such as phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, and benzyl (meth) acrylate.

And heterocyclic ring-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate, halogen atom-containing (meth) acrylates such as vinyl chloride-and fluorine atom-containing (meth) acrylates, silicon atom-containing (meth) acrylates such as silicone (meth) acrylates, and (meth) acrylates obtained from terpene compound derivative alcohols.

When such a copolymerizable monomer is used, the amount thereof is not particularly limited, and is usually preferably 0.01% by weight or more of the entire monomer components. The amount of the copolymerizable monomer may be 0.1% by weight or more, or 0.5% by weight or more, based on the whole monomer components, from the viewpoint of more effectively utilizing the effect of the use of the copolymerizable monomer. From the viewpoint of easily obtaining the balance of adhesive properties, the amount of the copolymerizable monomer used is usually preferably 50% by weight or less, and preferably 40% by weight or less, of the entire monomer components.

In some embodiments, the monomer component constituting the acrylic polymer (a) may contain a monomer having a nitrogen atom. By using a monomer having a nitrogen atom, the cohesive force of the adhesive can be increased, and the peel strength after photocuring can be suitably improved. As a preferable example of the monomer having a nitrogen atom, a monomer having a ring containing a nitrogen atom is mentioned. As the monomer having a nitrogen atom-containing ring, the above-exemplified monomers and the like can be used, and for example, general formula (1):

the N-vinyl cyclic amides shown. Here, in the general formula (1), R¹An organic group having a valence of 2, and specific examples thereof include- (CH)₂)_n-. Where n is an integer of 2 to 7 (preferably 2,3 or 4). Among them, N-vinyl-2-pyrrolidone can be preferably used. Other preferable examples of the monomer having a nitrogen atom include amide group-containing monomers such as (meth) acrylamide.

The amount of the monomer having a nitrogen atom (preferably, the monomer having a ring containing a nitrogen atom) to be used is not particularly limited, and may be, for example, 1% by weight or more, 3% by weight or more, and further 5% by weight or more, or 7% by weight or more of the entire monomer components. In one embodiment, the amount of the monomer having a nitrogen atom may be 10% by weight or more, 15% by weight or more, and 20% by weight or more of the entire monomer components. The amount of the monomer having a nitrogen atom to be used is, for example, preferably 40% by weight or less, and may be 35% by weight or less, 30% by weight or less, or 25% by weight or less, based on the whole monomer components. In another embodiment, the amount of the monomer having a nitrogen atom to be used may be, for example, 20% by weight or less, or 15% by weight or less of the entire monomer components.

In some embodiments, the monomer component constituting the acrylic polymer (a) may contain a hydroxyl group-containing monomer. By using the hydroxyl group-containing monomer, the cohesive force of the adhesive, the degree of crosslinking (for example, crosslinking based on an isocyanate crosslinking agent) can be appropriately adjusted. The amount of the hydroxyl group-containing monomer used is not particularly limited, and may be, for example, 0.01% by weight or more, 0.1% by weight or more, 0.5% by weight or more, 1% by weight or more, 5% by weight or more, or 10% by weight or more of the whole monomer component. In some embodiments, the amount of the hydroxyl group-containing monomer used is, for example, preferably 40% by weight or less, and may be 30% by weight or less, 25% by weight or less, and may be 20% by weight or less, based on the total monomer components, from the viewpoint of suppressing the water absorption of the pressure-sensitive adhesive layer. In another embodiment, the amount of the hydroxyl group-containing monomer used may be, for example, 15% by weight or less, 10% by weight or less, or 5% by weight or less of the entire monomer components.

In some embodiments, the proportion of the carboxyl group-containing monomer in the monomer component of the acrylic polymer (a) may be, for example, 2 wt% or less, 1 wt% or less, or 0.5 wt% or less (for example, less than 0.1 wt%). The monomer component of the acrylic polymer (a) may be substantially free of a carboxyl group-containing monomer. Here, the substantial absence of the carboxyl group-containing monomer means that at least the carboxyl group-containing monomer is not intentionally used. The pressure-sensitive adhesive layer containing the acrylic polymer (a) in which the amount of the carboxyl group-containing monomer is limited as described above is preferable from the viewpoint of preventing metal corrosion. The pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer is preferably used, for example, in such a manner that the pressure-sensitive adhesive layer is in contact with an adherend and/or a support having a metal material (which may be a support film containing a metal foil or a metal material).

In some embodiments, the monomer component constituting the acrylic polymer (a) may include a (meth) acrylate containing an alicyclic hydrocarbon group. This improves the cohesive strength of the adhesive and improves the peel strength after photocuring. As the alicyclic hydrocarbon group-containing (meth) acrylate, those exemplified above can be used, and for example, cyclohexyl acrylate and isobornyl acrylate can be preferably used. The amount of the alicyclic hydrocarbon group-containing (meth) acrylate to be used is not particularly limited, and may be, for example, 1% by weight or more, 3% by weight or more, or 5% by weight or more of the whole monomer components. In one embodiment, the amount of the alicyclic hydrocarbon group-containing (meth) acrylate used may be 10% by weight or more and 15% by weight or more of the entire monomer components. The upper limit of the amount of the (meth) acrylate containing an alicyclic hydrocarbon group is preferably about 40% by weight or less, and may be, for example, 30% by weight or less, and may be 25% by weight or less (for example, 15% by weight or less, further 10% by weight or less).

The polymerization method for forming (synthesizing) the polymer (a) from the monomer components is not particularly limited, and various conventionally known polymerization methods can be suitably used. For example, thermal polymerization such as solution polymerization, emulsion polymerization, and bulk polymerization (typically, in the presence of a thermal polymerization initiator); photopolymerization by irradiation with light such as ultraviolet rays (typically, in the presence of a photopolymerization initiator); radiation polymerization by irradiation with radiation such as β -rays and γ -rays; and the like. It is also possible to carry out 2 or more polymerization methods in combination (for example, in stages).

As the solvent (polymerization solvent) for the solution polymerization, for example, aromatic compounds (typically aromatic hydrocarbons) selected from toluene and the like; esters such as ethyl acetate and butyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; halogenated alkanes such as 1, 2-dichloroethane; lower alcohols such as isopropyl alcohol (e.g., monohydric alcohols having 1 to 4 carbon atoms); ethers such as t-butyl methyl ether; ketones such as methyl ethyl ketone; etc. or a mixed solvent of 2 or more kinds.

In the polymerization, a known or conventional thermal polymerization initiator or photopolymerization initiator can be used depending on the polymerization method, polymerization system, and the like. Such a polymerization initiator may be used singly or in a suitable combination of two or more.

The thermal polymerization initiator is not particularly limited, and for example, an azo polymerization initiator, a peroxide initiator, a redox initiator based on a combination of a peroxide and a reducing agent, a substituted ethane initiator, and the like can be used. More specifically, examples of the azo initiator include 2,2 ' -Azobisisobutyronitrile (AIBN), 2 ' -azobis (2-methylpropionamidine) disulfate, 2 ' -azobis (2-amidinopropane) dihydrochloride, 2 ' -azobis [2- (5-methyl-2-imidazolin-2-yl) propane ] dihydrochloride, 2 ' -azobis (N, N ' -dimethyleneisobutyramidine), and 2,2 ' -azobis [ N- (2-carboxyethyl) -2-methylpropionamidine ] hydrate; persulfates such as potassium persulfate and ammonium persulfate; peroxide initiators such as benzoyl peroxide, t-butyl hydroperoxide and hydrogen peroxide; substituted ethane-based initiators such as phenyl-substituted ethane; redox initiators such as combinations of persulfate and sodium bisulfite and combinations of peroxide and sodium ascorbate; and the like, but are not limited thereto. The thermal polymerization can be suitably carried out at a temperature of, for example, about 20 to 100 ℃ (typically about 40 to 80 ℃), but is not limited thereto.

The photopolymerization initiator is not particularly limited, and for example, ketal photopolymerization initiator, acetophenone photopolymerization initiator, benzoin ether photopolymerization initiator, acylphosphine oxide photopolymerization initiator, α -ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, photoactive oxime photopolymerization initiator, benzoin photopolymerization initiator, benzil photopolymerization initiator, benzophenone photopolymerization initiator, thioxanthone photopolymerization initiator and the like can be used.

The amount of the polymerization initiator to be used may be any amount generally used in accordance with the polymerization method, polymerization system, etc., and is not particularly limited. For example, the polymerization initiator may be used in an amount of about 0.001 to 5 parts by weight (typically about 0.01 to 2 parts by weight, for example about 0.01 to 1 part by weight) based on 100 parts by weight of the monomer to be polymerized.

In the above polymerization, various conventionally known chain transfer agents (which may be understood as a molecular weight regulator or a polymerization degree regulator) may be used as necessary. As the chain transfer agent, mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, thioglycolic acid and α -thioglycerol can be used. Alternatively, a chain transfer agent containing no sulfur atom (non-sulfur chain transfer agent) may be used. Specific examples of the non-sulfur chain transfer agent include: anilines such as N, N-dimethylaniline and N, N-diethylaniline; terpenes such as α -pinene and terpinolene; styrenes such as α -methylstyrene and α -methylstyrene dimer; compounds having benzylidene group such as dibenzylidene acetone, cinnamyl alcohol and cinnamyl aldehyde; hydroquinones such as hydroquinone and dihydroxynaphthalene; quinones such as benzoquinone and naphthoquinone; olefins such as 2, 3-dimethyl-2-butene and 1, 5-cyclooctadiene; alcohols such as phenol, benzyl alcohol and allyl alcohol; benzyl hydrides such as diphenylbenzene and triphenylbenzene; and the like. The chain transfer agent may be used alone in 1 kind or in combination of 2 or more kinds. The techniques disclosed herein may be suitably carried out without using a chain transfer agent.

The amount of the chain transfer agent used may be, for example, about 0.005 to 1 part by weight based on 100 parts by weight of the monomer component. In some embodiments, the amount of the chain transfer agent used may be, for example, 0.01 part by weight or more, 0.03 part by weight or more, 0.05 part by weight or more, and 0.07 part by weight or more, relative to 100 parts by weight of the monomer component, from the viewpoint of impact resistance. In some embodiments, the amount of the chain transfer agent used may be, for example, 0.5 parts by weight or less, 0.2 parts by weight or less, 0.1 parts by weight or less, or less than 0.1 parts by weight (for example, 0.09 parts by weight or less) relative to 100 parts by weight of the monomer component, from the viewpoint of deformation resistance.

In the technique disclosed herein, the glass transition temperature (Tg) of the polymer (A) is not particularly limited, and usually less than 0 ℃ is suitable, preferably less than-10 ℃ and preferably less than-20 ℃. The Tg of the polymer (a) is lowered, and the impact resistance tends to be improved. In some embodiments, the Tg of polymer (A) may be less than-25 deg.C, and may be less than-30 deg.C. The Tg of the polymer (A) is typically-80 ℃ or higher, and may be, for example, -70 ℃ or higher, may be-60 ℃ or higher, and may be-55 ℃ or higher. From the viewpoint of improving the tensile modulus, the Tg of the polymer (A) may be preferably-50 ℃ or higher, more preferably-45 ℃ or higher, may be-40 ℃ or higher, may be-38 ℃ or higher, and may be-35 ℃ or higher in some embodiments.

Herein, in the present specification, the Tg of the polymer means: tg determined by Fox's equation based on the composition of the monomer components used in the preparation of the polymer. The above formula Fox is a relational expression between Tg of the copolymer and glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of monomers constituting the copolymer, as shown below.

1/Tg＝Σ(Wi/Tgi)

In the Fox formula, Tg represents the glass transition temperature (unit: K) of the copolymer, Wi represents the weight fraction (copolymerization ratio on a weight basis) of the monomer i in the copolymer, and Tgi represents the glass transition temperature (unit: K) of the homopolymer of the monomer i. When the polymer of a particular target of Tg is a homopolymer, the Tg of the homopolymer is consistent with the Tg of the target polymer.

As the glass transition temperature of the homopolymer used for calculation of Tg, the value described in the known data was used. For example, the following monomers are used as the glass transition temperature of the homopolymer of the monomer.

As for the glass transition temperature of the homopolymer of the monomer other than those exemplified in the above, the value described in "polymer handbook" (third edition, john wiley & Sons, inc., 1989) was used. In this document, it is described that when a plurality of values are used, the highest value is used.

The weight average molecular weight (Mw) of the polymer (a) is not particularly limited. From the viewpoint of achieving both the deformation resistance and the impact resistance in a well-balanced manner, the Mw of the polymer (a) may be, for example, about 10 × 10 in some embodiments⁴The above is suitable, preferably more than 20X 10⁴May exceed 30X 10⁴May exceed 40X 10⁴May exceed 50X 10⁴. Further, the upper limit of Mw of the polymer (A) may be usually about 500X 10⁴The following. From the sealing to the adherendIn some embodiments, the Mw of the polymer (a) may be, for example, 150 × 10 from the viewpoint of compatibility and peel strength⁴Hereinafter, it may be 100 × 10⁴Hereinafter, it may be 90 × 10⁴Hereinafter, it may be 75 × 10⁴The following. Here, Mw is a value in terms of standard polystyrene obtained by Gel Permeation Chromatography (GPC). As the GPC apparatus, for example, the model name "HLC-8320 GPC" (column: TSKgel GMH-H (S), manufactured by Tosoh corporation) can be used. The same applies to the later-described embodiments. The above-mentioned Mw examples can be used for the Mw of the polymer (a) in the adhesive layer of the adhesive sheet disclosed herein, and also for the Mw of the polymer (a) in the adhesive composition used for forming the adhesive layer.

(photoreactive monomer (B))

The adhesive layer in the technology disclosed herein may contain a photoreactive monomer (B) in addition to the polymer (a) (e.g., acrylic polymer (a)) as described above. As the photoreactive monomer (B), a compound having 2 or more ethylenically unsaturated groups contained in a molecule (hereinafter also referred to as "functional group number") can be used. The upper limit of the number of functional groups of the compound used as the photoreactive monomer (B) is not particularly limited. The number of the functional group may be, for example, 50 or less, 40 or less, 30 or less, 20 or less, and 15 or less. In some embodiments, a compound having an ethylenically unsaturated group with a functional group number of, for example, 2 to 10, preferably 2 to 8, and more preferably 2 to 6, may be used. The photoreactive monomer (B) may be used alone in 1 kind or in combination of 2 or more kinds.

The photoreactive monomer (B) contained in the pressure-sensitive adhesive layer is adhered to an adherend and then irradiated with light (e.g., ultraviolet light) to react the ethylenically unsaturated group, whereby a crosslinked structure can be formed. The pressure-sensitive adhesive sheet containing the photoreactive monomer (B) in the pressure-sensitive adhesive layer is adhered to an adherend, and then the pressure-sensitive adhesive layer is cured by ultraviolet irradiation or the like, whereby the deformation resistance of the pressure-sensitive adhesive layer can be improved. This makes it possible to suitably achieve both good conformability to the surface shape of an adherend when the adhesive is adhered to the adherend and high deformation resistance after adhesion.

Examples of the above ethylenically unsaturated group include, but are not limited to, acryloyl, methacryloyl, vinyl and allyl groups. The photoreactive monomer (B) may have 2 or more ethylenically unsaturated groups in the molecule, which are the same as each other, or may have 2 or more different groups. From the viewpoint of photoreactivity, preferable ethylenically unsaturated groups include acryloyl and methacryloyl. Among them, acryloyl is preferable.

The functional group equivalent of the compound used as the photoreactive monomer (B) is not particularly limited. The functional group equivalent may be, for example, about 50 to 10000g/mol, about 50 to 8000g/mol, about 50 to 5000g/mol, about 50 to 3000g/mol, or about 50 to 2000 g/mol. In some embodiments, the photoreactive monomer (B) may preferably be a compound having a functional group equivalent of about 60 to 800g/mol (more preferably about 80 to 600 g/mol) from the viewpoint of photocurability.

The functional group equivalent of the photoreactive monomer (B) can be calculated by dividing the molecular weight [ g/mol ] of the photoreactive monomer (B) by the number of ethylenically unsaturated functional groups of the photoreactive monomer (B). The molecular weight of the photoreactive monomer (B) can be obtained as a weight average molecular weight in terms of standard polystyrene by a Gel Permeation Chromatography (GPC) method, for example. Further, as the molecular weight [ g/mol ] of the photoreactive monomer (B), a manufacturer's nominal value or a molecular weight calculated from a molecular structure may be used.

The molecular weight of the photoreactive monomer (B) is not particularly limited, and may be selected so as to exhibit a desired effect as appropriate. For example, as the photoreactive monomer (B), a monomer having a molecular weight of about 20000 or less can be used. From the viewpoint of ease of preparation of the adhesive composition, coatability, and the like, the molecular weight of the photoreactive monomer (B) may be, for example, 16000 or less, may be 10000 or less, may be 4000 or less, may be 1500 or less, and may be 1000 or less in some embodiments. The molecular weight of the photoreactive monomer (B) is, for example, 100 or more, typically 120 or more. From the viewpoint of processability, handleability, and the like of the adhesive sheet, the molecular weight of the photoreactive monomer (B) may be, for example, 150 or more, 200 or more, 280 or more, 350 or more, 420 or more, 480 or more, and 550 or more in some embodiments.

In the adhesive sheet disclosed herein, the amount of the photoreactive monomer (B) contained in the adhesive layer is not particularly limited, and may be appropriately set according to the target performance (for example, tensile modulus of the adhesive layer after photocuring). In some embodiments in which the adhesive layer contains the polymer (a) and the photoreactive monomer (B), the amount of the photoreactive monomer (B) may be, for example, 1 part by weight or more, and usually 3 parts by weight or more is suitable, relative to 100 parts by weight of the polymer (a) contained in the adhesive layer. From the viewpoint of easily improving the tensile modulus of the pressure-sensitive adhesive layer after photocuring, the amount of the photoreactive monomer (B) may be 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, and 20 parts by weight or more, relative to 100 parts by weight of the polymer (a). From the viewpoints of the aggregation of the pressure-sensitive adhesive layer before photocuring and the handling (e.g., processability) of the pressure-sensitive adhesive sheet, the amount of the photoreactive monomer (B) is usually preferably 80 parts by weight or less, more preferably 60 parts by weight or less, and may be 50 parts by weight or less, 40 parts by weight or less, and may be 35 parts by weight or less, based on 100 parts by weight of the polymer (a).

In some embodiments, the adhesive layer preferably contains at least a compound B1 having a ring structure and 2 or more ethylenically unsaturated groups in a molecule as the photoreactive monomer (B). According to the adhesive layer containing the compound B1 having such a structure, the deformation resistance of the adhesive layer can be effectively improved by light irradiation. The ring in the above ring structure may be an aliphatic ring or an aromatic ring. The ring may be a carbocyclic ring or a heterocyclic ring. The number of rings contained in one molecule of compound B1 may be 1, and may be 2 or more. The upper limit of the number of rings contained in the compound B1 is not particularly limited, and may be, for example, 100 or less, 70 or less, 50 or less, 30 or less, 15 or less, 8 or less, 6 or less, 5 or less, and 4 or less. When compound B1 contains more than 2 rings, these rings optionally form a fused ring formed from 1 or more than 2 rings (typically, a bicyclic or tricyclic fused ring). The above-mentioned ring is preferably contained in the main chain of compound B1. Namely, it is preferable that: one ethylenically unsaturated group of the compound B1 is linked to at least one other ethylenically unsaturated group via the above-mentioned ring structure. The compound B1 may be used alone in 1 kind or in combination of 2 or more kinds.

As the compound B1, a compound having a cyclic structure and 2 or more ethylenically unsaturated groups in the molecule and having a functional group equivalent of 100g/mol or more can be preferably used. According to the pressure-sensitive adhesive sheet containing the compound B1 satisfying the functional group equivalent in the pressure-sensitive adhesive layer, a joint having high deformation resistance and high impact resistance can be suitably formed. The reason why such an effect can be obtained is not particularly limited, but it is considered that: according to compound B1, the tensile modulus of the pressure-sensitive adhesive layer after light irradiation can be effectively increased due to the rigidity of the ring structure to impart deformation resistance, while the distance between the crosslinking points can be maintained by setting the equivalent weight of the functional group of compound B1 to a predetermined value or more, thereby forming a crosslinked structure having high impact resistance. In some embodiments, the functional group equivalent weight of compound B1 can be, for example, 120g/mol or more, 150g/mol or more, 180g/mol or more, 230g/mol or more, 280g/mol or more, 320g/mol or more, and 350g/mol or more. As the functional group equivalent of compound B1 increases, the impact resistance tends to improve. The functional group equivalent of the compound B1 may be, for example, 10000g/mol or less, 8000g/mol or less, 5000g/mol or less, 3000g/mol or less, and 2000g/mol or less. In some embodiments, the functional group equivalent weight of the compound B1 is preferably 800g/mol or less, more preferably 600g/mol or less, from the viewpoint of photocurability and the like. In some embodiments, the functional group equivalent weight of compound B1 can be 500g/mol or less, can be 400g/mol or less, and can be 300g/mol or less.

In some embodiments, the number of functional groups (i.e., the number of ethylenically unsaturated groups contained in the molecule) of the compound B1 may be, for example, 2 to 50, 2 to 40, 2 to 30, 2 to 10, preferably 2 to 6, 2 to 4, and 2 to 3. In some embodiments, it may be preferable to use compound B1 having a functional group number of 2.

Compound B1 may have functional groups other than ethylenically unsaturated groups. Examples of the functional group other than the ethylenically unsaturated group include a hydroxyl group, a carboxyl group, and an amino group. Preferred examples of the functional group other than the ethylenically unsaturated group include a hydroxyl group and an amino group.

Examples of the compound B1 include bisphenol a glycidyl ether (meth) acrylic acid adducts, bisphenol a glycidyl amine (meth) acrylic acid adducts, bisphenol a glycidyl ester (meth) acrylic acid adducts, and bisphenol a epoxy (meth) acrylates; alkylene oxide-modified bisphenol a (meth) acrylates such as Ethylene Oxide (EO) -modified bisphenol a di (meth) acrylate and Propylene Oxide (PO) -modified bisphenol a di (meth) acrylate; bisphenol F epoxy (meth) acrylates such as bisphenol F glycidyl ether (meth) acrylic acid adducts, bisphenol F glycidyl amine (meth) acrylic acid adducts, bisphenol F glycidyl ester (meth) acrylic acid adducts, and the like; alkylene oxide-modified bisphenol F (meth) acrylates such as EO-modified bisphenol F di (meth) acrylate and PO-modified bisphenol F di (meth) acrylate; bisphenol E type epoxy (meth) acrylates such as bisphenol E glycidyl ether (meth) acrylic acid adducts, bisphenol E glycidyl amine (meth) acrylic acid adducts, bisphenol E glycidyl ester (meth) acrylic acid adducts, and the like; alkylene oxide-modified bisphenol E (meth) acrylates such as EO-modified bisphenol E di (meth) acrylate and PO-modified bisphenol E di (meth) acrylate; (meth) acrylates having a fluorene skeleton such as 9, 9-bis (4-hydroxyphenyl) fluorene di (meth) acrylate and 9, 9-bis [4- (2-hydroxyethoxy) phenyl ] fluorene di (meth) acrylate; (meth) acrylates having an aliphatic ring (which may be an alicyclic fused ring.) such as tricyclodecane dimethanol di (meth) acrylate, hydrogenated bisphenol a type epoxy (meth) acrylate, hydrogenated bisphenol F type epoxy (meth) acrylate, hydrogenated bisphenol E type epoxy (meth) acrylate, hydrogenated phthalic acid type epoxy (meth) acrylate, hydrogenated terpene phenol (meth) acrylate, 1, 4-cyclohexanedimethanol diglycidyl ether (meth) acrylate, and the like; (meth) acrylic acid adducts of novolak-type epoxy resins; (meth) acrylic acid adducts of thioether type epoxy resins; (meth) acrylic acid adducts of naphthalene type epoxy resins; (meth) acrylic acid adducts of dicyclopentadiene type epoxy resins; (meth) acrylic acid adducts of alkyldiphenol type epoxy resins; (meth) acrylic acid adducts of biphenyl type epoxy resins; (meth) acrylic acid adducts of terpene phenol resins; isocyanurate type (meth) acrylates such as tris (2-hydroxyethyl) isocyanurate di (meth) acrylate and tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate; divinylbenzene; hydroquinone di (meth) acrylate; resorcinol di (meth) acrylate; modified products of any of the above materials (e.g., amine-modified products, acid-modified products, and halogen-modified products); and the like, but are not limited thereto. In some modes, it may be preferable to use the compound B1 having an aromatic carbocyclic ring. Preferred examples of the compound B1 include compounds having a bisphenol a structure such as bisphenol a-type epoxy (meth) acrylate, alkylene oxide-modified bisphenol a (meth) acrylate, and modified products thereof (e.g., amine-modified products).

Commercially available products usable as compound B1 include, but are not limited to, trade names "A-DCP", "A-BPE-4" manufactured by Ningzhou chemical industry, "Viscoa # 540", "Viscoa #700 HV" manufactured by Osaka organic chemical industry, "R-114F" manufactured by Nippon Kagaku Co., Ltd, "Epoxy Ester 3000A", "Epoxy Ester 80 MFA", Daicel Ornex Co., Ltd, "EBECRYL 3700", "EBECRYL 3703", and "EBECRYL 3603".

The amount of the compound B1 is not particularly limited, and may be, for example, 0.5 part by weight or more, based on 100 parts by weight of the polymer (a) contained in the pressure-sensitive adhesive layer. From the viewpoint of easily obtaining a pressure-sensitive adhesive layer having both deformation resistance and impact resistance in a well-balanced manner, the amount of the compound B1 may be, for example, 1 part by weight or more, 3 parts by weight or more, 5 parts by weight or more, 7 parts by weight or more, 10 parts by weight or more, and 15 parts by weight or more, relative to 100 parts by weight of the polymer (a) in some embodiments. From the viewpoint of the aggregation property of the pressure-sensitive adhesive layer before photocuring and the handling property of the pressure-sensitive adhesive sheet, the amount of the compound B1 is usually preferably 80 parts by weight or less, preferably 60 parts by weight or less, and may be 50 parts by weight or less, 40 parts by weight or less, and may be 35 parts by weight or less, based on 100 parts by weight of the polymer (a).

In some embodiments, the adhesive layer may include, as the photoreactive monomer (B), a compound B2 having a functional group number of 2 or more and no ring structure in a molecule. Compound B2 is preferably used in combination with compound B1. This makes it possible to adjust the crosslinked structure of the pressure-sensitive adhesive layer and to form a joint that more suitably achieves both deformation resistance and impact resistance. The compound B2 may be used alone in 1 kind or in combination of 2 or more kinds.

The number of functional groups of the compound B2 may be, for example, 50 or less, 40 or less, 30 or less, 20 or less, and 15 or less. The number of functional groups of the compound B2 used in some embodiments may be, for example, 2 to 10, preferably 3 to 10, 3 to 8, and 4 to 6. For example, in the case of using a compound having a functional group number of 2 as compound B1, it may be advantageous to use compound B2 having a functional group number of 3 or more (preferably 4 or more, more preferably 5 or more, and still more preferably 6 or more).

The functional group equivalent of the compound B2 is not particularly limited, and may be, for example, 5000g/mol or less, 2000g/mol or less, or 1000g/mol or less. In some embodiments, the functional group equivalent of the compound B2 may be, for example, 600g/mol or less, and may be 400g/mol or less, 300g/mol or less, 200g/mol or less, 150g/mol or less, and 100g/mol or less from the viewpoint of improving photocurability, hardness of a cured product, and the like. The functional group equivalent of the compound B2 is typically 50g/mol or more, preferably 60g/mol or more, and may be 70g/mol or more, 80g/mol or more, and may be 90g/mol or more.

Examples of compounds that can be used as compound B2 include: pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, trimethylolethane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, neopentyl glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, EO-modified products, PO-modified products of any of the above materials, and the like, but are not limited thereto.

In the embodiment using the compound B2, the amount of the compound B2 is not particularly limited, and may be, for example, 0.1 part by weight or more based on 100 parts by weight of the polymer (a) contained in the pressure-sensitive adhesive layer. From the viewpoint of easily obtaining a pressure-sensitive adhesive layer having both deformation resistance and impact resistance in a well-balanced manner, the amount of compound B2 may be, for example, 1 part by weight or more, 2 parts by weight or more, 4 parts by weight or more, 6 parts by weight or more, 10 parts by weight or more, and 12 parts by weight or more, relative to 100 parts by weight of polymer (a) in some embodiments. In some embodiments, the amount of the compound B2 is, for example, 25 parts by weight or less, preferably 17 parts by weight or less, and may be 15 parts by weight or less, 13 parts by weight or less, and may be 9 parts by weight or less, based on 100 parts by weight of the polymer (a), from the viewpoint of suppressing a decrease in adhesion to an adherend due to excessive crosslinking.

In the mode of using the compound B1 and the compound B2 in combination, as the compound B2, a compound having a functional group equivalent smaller than that of the compound B1 in which the number of functional groups is 3 or more and which is used in combination therewith can be preferably used. In some embodiments, the functional group equivalent FE relative to compound B1₁Functional group equivalent FE of Compound B2₂Ratio of (FE)₂/FE₁) For example, it may be 0.9 or less, may be 0.7 or less,may be 0.5 or less, and may be 0.4 or less. According to the above-mentioned aspect, the tensile modulus improving effect by the photoreactive monomer (B) can be effectively exhibited. The above ratio (FE)₂/FE₁) The lower limit of (b) is not particularly limited, and may be, for example, 0.01 or more, 0.1 or more, and 0.2 or more.

In the case of using the compound B1 and the compound B2 in combination, the amount W of the compound B2 used is₂Amount W used relative to Compound B1₁Weight ratio of (W)₂/W₁) There is no particular limitation. In some forms, the weight ratio (W) is₂/W₁) For example, the concentration of the surfactant may be 0.05 to 10, 0.1 to 5, 0.2 to 3, and 0.3 to 2. By making the weight ratio (W)₂/W₁) In any of the above ranges, the effects of the combined use of compound B1 and compound B2 tend to be exhibited as appropriate.

In some embodiments of the adhesive sheet disclosed herein, the photoreactive monomer (B) may be contained in a free form in the adhesive layer. The above adhesive layer can be suitably formed by using an adhesive composition containing the photoreactive monomer (B) in a free form. By "free form" is meant herein: the photoreactive monomer (B) is not chemically bonded to the adhesive layer or other components (e.g., the polymer (a)) included in the adhesive composition. From the viewpoint of ease of preparation and suppression of gelation, a binder composition containing the photoreactive monomer (B) in a free form may be advantageous.

In some other embodiments of the pressure-sensitive adhesive sheet disclosed herein, at least a part of the photoreactive monomer (B) may be contained in the pressure-sensitive adhesive layer so as to be chemically bonded to the pressure-sensitive adhesive layer or other components contained in the pressure-sensitive adhesive composition (for example, the polymer (a), a crosslinking agent described later, and the like), from the viewpoint of improving processability of the pressure-sensitive adhesive sheet and the like. The chemical bond may be formed, for example, by a reaction between a functional group F1 other than an ethylenically unsaturated group in the molecule of the photoreactive monomer (B) and a functional group F2 which is a functional group in the molecule of the other component and is capable of reacting with the functional group F1. The other component may be a crosslinking agent, and the photoreactive monomer (B) may be bonded to the polymer (a) through the crosslinking agent.

(acrylic acid oligomer)

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet disclosed herein may contain an acrylic oligomer from the viewpoints of improving the cohesive strength, improving the adhesiveness to the surface adjacent to the pressure-sensitive adhesive layer (for example, the surface of a support in the pressure-sensitive adhesive sheet, the surface of an adherend to which the pressure-sensitive adhesive sheet is attached, and the like). The adhesive layer containing an acrylic oligomer can be suitably formed using an adhesive composition containing the acrylic oligomer. As the acrylic oligomer, those having a Tg higher than that of the polymer (A) can be preferably used.

The Tg of the acrylic oligomer is not particularly limited, and may be, for example, about 20 ℃ or higher and about 300 ℃ or lower. The Tg may be, for example, about 30 ℃ or higher, about 40 ℃ or higher, about 60 ℃ or higher, about 80 ℃ or higher or about 100 ℃ or higher. When the Tg of the acrylic oligomer is high, the effect of improving the cohesive force tends to be substantially increased. From the viewpoint of anchorage to the support, impact absorption, and the like, the Tg of the acrylic oligomer may be, for example, about 250 ℃ or less, about 200 ℃ or less, about 180 ℃ or less, or about 150 ℃ or less. The Tg of the acrylic oligomer is the same as the Tg of the polymer (a), and is a value calculated based on the Fox equation.

The Mw of the acrylic oligomer is not particularly limited, and may be, for example, about 1000 or more, usually about 1500 or more, suitably about 2000 or more, and may be about 3000 or more. In addition, the Mw of the acrylic oligomer may be, for example, less than about 30000, typically less than about 10000 is suitable, may be less than about 7000, and may be less than about 5000. When Mw is within the above range, the effect of improving the aggregation property of the pressure-sensitive adhesive layer and the adhesiveness to the adjacent surface can be easily and suitably exhibited. The Mw of the acrylic oligomer can be measured by Gel Permeation Chromatography (GPC) and determined as a value in terms of standard polystyrene. Specifically, for example, HPLC8020 available from Tosoh corporation can be measured using TSKgel GMH-H (20). times.2 columns and tetrahydrofuran solvent at a flow rate of about 0.5 mL/min.

Examples of the monomer component constituting the acrylic oligomer include the following (meth) acrylate monomers: the above-mentioned (meth) acrylic acids C_1-20An alkyl ester; the various alicyclic hydrocarbon group-containing (meth) acrylates described above; the above-mentioned various aromatic hydrocarbon group-containing (meth) acrylates; (meth) acrylic acid esters obtained from alcohols which are terpene compound derivatives, and the like. These may be used alone in 1 kind or in combination of 2 or more kinds.

From the viewpoint of improving adhesiveness, the acrylic oligomer preferably contains an alkyl (meth) acrylate having a branched structure with an alkyl group such as isobutyl (meth) acrylate or tert-butyl (meth) acrylate; an acrylic monomer having a relatively large volume structure represented by an alicyclic hydrocarbon group-containing (meth) acrylate, an aromatic hydrocarbon group-containing (meth) acrylate, or the like is used as a monomer unit. In addition, in the case of using ultraviolet rays when synthesizing an acrylic oligomer or when producing an adhesive layer, a monomer having a saturated hydrocarbon group at the ester end is preferable from the viewpoint of being less likely to cause inhibition of polymerization, and for example, an alkyl (meth) acrylate having an alkyl group with a branched structure or a (meth) acrylate containing a saturated alicyclic hydrocarbon group is preferably used.

The proportion of the (meth) acrylate ester monomer in the total monomer components constituting the acrylic oligomer is typically more than 50% by weight, preferably 60% by weight or more, and more preferably 70% by weight or more (for example, 80% by weight or more, and further 90% by weight or more). In a preferred embodiment, the acrylic oligomer has a monomer composition substantially consisting of only 1 or 2 or more (meth) acrylate monomers. For example, the monomer components constituting the acrylic oligomer comprise a (meth) acrylate containing an alicyclic hydrocarbon group and a (meth) acrylic acid C_1-20In the case of the alkyl ester, the weight ratio thereof is not particularly limited. In some embodiments, the (meth) acrylate containing an alicyclic hydrocarbon group/(meth) acrylic acid C_1-20The weight ratio of the alkyl ester may be, for example, 10/90 or more, 20/80 or more, or 30/70 or more, or 90/10 or less, 80/20 or less, or 70/30 or less.

As the constituent monomer component of the acrylic oligomer, a functional group-containing monomer may be used as needed in addition to the above-mentioned (meth) acrylate monomer. Examples of the functional group-containing monomer include monomers having a nitrogen atom-containing heterocycle, such as N-vinyl-2-pyrrolidone and N-acryloylmorpholine; amino group-containing monomers such as N, N-dimethylaminoethyl (meth) acrylate; amide group-containing monomers such as N, N-diethyl (meth) acrylamide; carboxyl group-containing monomers such as Acrylic Acid (AA) and methacrylic acid (MAA); hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate. These functional group-containing monomers may be used alone or in combination of two or more. When the functional group-containing monomer is used, the proportion of the functional group-containing monomer in the total monomer components constituting the acrylic oligomer may be, for example, 1% by weight or more, 2% by weight or more, or 3% by weight or more, or, for example, 15% by weight or less, 10% by weight or less, or 7% by weight or less. The acrylic oligomer may be one which does not use a monomer having a functional group.

Examples of preferable acrylic oligomers include dicyclopentyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBXMA), isobornyl acrylate (IBXA), dicyclopentyl acrylate (DCPA), 1-adamantyl methacrylate (ADMA), and homopolymers of 1-adamantyl acrylate (ADA), as well as copolymers of DCPMA and MMA, copolymers of DCPMA and IBXMA, copolymers of ADA and Methyl Methacrylate (MMA), copolymers of CHMA and isobutyl methacrylate (IBMA), copolymers of CHMA and IBXMA, copolymers of CHMA and Acryloylmorpholine (ACMO), copolymers of CHMA and Diethylacrylamide (DEAA), and copolymers of CHMA and AA.

The acrylic oligomer can be formed by polymerizing its constituent monomer components. The polymerization method and polymerization method are not particularly limited, and various conventionally known polymerization methods (for example, solution polymerization, emulsion polymerization, bulk polymerization, photopolymerization, and radiation polymerization) can be used as appropriate. The amount of the polymerization initiator and the amount of the chain transfer agent (e.g., thiol) optionally used may be appropriately set according to the kind of the polymerization initiator (e.g., azo polymerization initiator) to be used as needed, as exemplified with respect to the synthesis of the acrylic polymer (a), based on the technical common knowledge so that the desired molecular weight is obtained, and thus detailed description thereof is omitted.

When the acrylic oligomer is contained in the pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition, the content thereof may be, for example, 0.01 parts by weight or more based on 100 parts by weight of the polymer (a), and from the viewpoint of obtaining higher effects, may be 0.05 parts by weight or more, and may be 0.1 parts by weight or more, or 0.2 parts by weight or more. From the viewpoint of compatibility with the polymer (a), the content of the acrylic oligomer is preferably usually less than 50 parts by weight, more preferably less than 30 parts by weight, even more preferably less than 25 parts by weight, for example, 10 parts by weight or less, and may be 5 parts by weight or less or 1 part by weight or less, based on 100 parts by weight of the polymer (a). Or an adhesive layer or an adhesive composition containing no acrylic oligomer.

The pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition of the pressure-sensitive adhesive sheet disclosed herein may contain, as other optional components, various additives that are generally used in the field of a tackifier resin (e.g., rosin-based, petroleum-based, terpene-based, phenol-based, ketone-based, etc.) a viscosity modifier (e.g., thickener), a leveling agent, a plasticizer, a filler, a colorant such as a pigment, a dye, a stabilizer, an antiseptic, an anti-aging agent, etc., and the like. Conventionally known additives can be used for such various additives by a conventional method, and a detailed description thereof will be omitted since the present invention is not particularly characterized.

The technology disclosed herein can exhibit good adhesion without using the above tackifier resin. Therefore, in some embodiments, the content of the tackifier resin in the adhesive layer or the adhesive composition may be, for example, less than 10 parts by weight, and further less than 5 parts by weight, based on 100 parts by weight of the polymer (a). The content of the tackifier resin may be less than 1 part by weight (for example, less than 0.5 part by weight) and may be less than 0.1 part by weight (0 part by weight or more and less than 0.1 part by weight). The adhesive layer or the adhesive composition may not contain a tackifying resin.

When the adhesive sheet disclosed herein is used in optical applications, the adhesive layer of the adhesive sheet may have predetermined optical properties (e.g., transparency). From the viewpoint of such optical characteristics, it is preferable that the amounts of the polymer (a) and the components other than the above-mentioned photoreactive monomer (B) used as needed in the pressure-sensitive adhesive layer (even the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer) are limited. In the technique disclosed herein, the amount of the components other than the polymer (a) and the photoreactive monomer (B) in the adhesive layer is generally about 30% by weight or less, about 15% by weight or less is suitable, and about 12% by weight or less (e.g., about 10% by weight or less) is preferred. In the psa sheet according to one embodiment, the amount of components other than the polymer (a) and the photoreactive monomer (B) in the psa layer may be about 5 wt% or less, about 3 wt% or less, and about 1.5 wt% or less (e.g., about 1 wt% or less).

(crosslinking agent)

A crosslinking agent may be used in the adhesive layer as needed. In the pressure-sensitive adhesive sheet disclosed herein, the crosslinking agent is typically contained in the pressure-sensitive adhesive layer in a form after a crosslinking reaction. By using the crosslinking agent, the cohesive force of the adhesive layer and the like can be appropriately adjusted. In addition, in the pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer contains the photoreactive monomer (B), by using the crosslinking agent and the photoreactive monomer (B) in combination, both flexibility of the pressure-sensitive adhesive layer before photocuring of the photoreactive monomer and deformation resistance of the pressure-sensitive adhesive layer after photocuring can be suitably satisfied.

The type of the crosslinking agent is not particularly limited, and may be selected from among conventionally known crosslinking agents, for example, in such a manner that the crosslinking agent exerts an appropriate crosslinking function in the pressure-sensitive adhesive layer depending on the composition of the pressure-sensitive adhesive composition. Examples of the crosslinking agent that can be used include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a carbodiimide-based crosslinking agent, a melamine-based crosslinking agent, a urea-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelate-based crosslinking agent, a metal salt-based crosslinking agent, a hydrazine-based crosslinking agent, and an amine-based crosslinking agent. These may be used alone or in combination of two or more.

As the isocyanate-based crosslinking agent, a polyfunctional isocyanate compound having two or more functional groups can be used. Examples thereof include aromatic isocyanates such as toluene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris (p-isocyanatophenyl) thiophosphate, and diphenylmethane diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate; and the like. Examples of commercially available products include trimethylolpropane/tolylene diisocyanate trimer adduct (product name "Coronate L" manufactured by tokyo corporation), trimethylolpropane/1 hexamethylene diisocyanate trimer adduct (product name "Coronate HL" manufactured by tokyo corporation), 1 hexamethylene diisocyanate isocyanurate (product name "Coronate HX" manufactured by tokyo corporation), trimethylolpropane/xylylene diisocyanate adduct (product name "TAKENATE D-110N" manufactured by mitsui chemical co., ltd.).

The epoxy crosslinking agent is not particularly limited and may be one having 2 or more epoxy groups in 1 molecule. Preferably an epoxy crosslinking agent having 3 to 5 epoxy groups in 1 molecule. Specific examples of the epoxy-based crosslinking agent include N, N' -tetraglycidyl m-xylylenediamine, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1, 6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, and polyglycerol polyglycidyl ether. Commercially available epoxy crosslinking agents include trade names "TETRAD-X" and "TETRAD-C" manufactured by Mitsubishi gas chemical corporation, trade name "EPICLON CR-5L" manufactured by DIC corporation, trade name "Denacol EX-512" manufactured by Nagase Chemtex corporation, and trade name "TEPIC-G" manufactured by Nissan chemical industry corporation.

As the oxazoline-based crosslinking agent, a crosslinking agent having 1 or more oxazoline groups in 1 molecule can be used without particular limitation.

Examples of the aziridine-based crosslinking agent include trimethylolpropane tris [3- (1-aziridinyl) propionate ], trimethylolpropane tris [3- (1- (2-methyl) aziridinyl propionate ], and the like.

As the carbodiimide-based crosslinking agent, a low molecular weight compound or a high molecular weight compound having 2 or more carbodiimide groups can be used.

In some embodiments, peroxides may be used as crosslinking agents. Examples of the peroxide include di (2-ethylhexyl) peroxydicarbonate, di (4-tert-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,3, 3-tetramethylbutyl peroxyisobutyrate, and dibenzoyl peroxide. Of these, examples of the peroxide having particularly excellent crosslinking reaction efficiency include bis (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and dibenzoyl peroxide. When a peroxide is used as the polymerization initiator, the peroxide remaining unused in the polymerization reaction may be used in the crosslinking reaction. In this case, the residual amount of the peroxide is determined, and when the proportion of the peroxide does not satisfy a predetermined amount, the peroxide may be added to the reaction mixture in a predetermined amount as needed. The peroxide can be quantified by the method described in Japanese patent No. 4971517. The peroxide can be quantitatively determined by the method described in Japanese patent No. 4971517.

The amount of the crosslinking agent used (the total amount of 2 or more crosslinking agents used) is not particularly limited. From the viewpoint of achieving a pressure-sensitive adhesive that exhibits good balance of adhesive properties such as adhesive strength and cohesive strength, the amount of the crosslinking agent to be used is preferably about 5 parts by weight or less, and may be 3 parts by weight or less, 2 parts by weight or less, 1 part by weight or less, and may be less than 1 part by weight, based on 100 parts by weight of the polymer (a). In the case of using the crosslinking agent and the photoreactive monomer (B) in combination, the amount of the crosslinking agent to be used may be, for example, 0.80 parts by weight or less, 0.60 parts by weight or less, 0.30 parts by weight or less, or 0.10 parts by weight or less, based on 100 parts by weight of the polymer (a), from the viewpoint of easily and suitably exerting the effects of the above-described combined use. The lower limit of the amount of the crosslinking agent is not particularly limited, and may be used in an amount of more than 0 part by weight relative to 100 parts by weight of the polymer (a). In some embodiments, the crosslinking agent may be used in an amount of, for example, 0.001 parts by weight or more, 0.01 parts by weight or more, and 0.03 parts by weight or more, based on 100 parts by weight of the polymer (a).

The technique disclosed herein can be preferably implemented in a manner of using at least an isocyanate-based crosslinking agent as a crosslinking agent. Combinations of isocyanate-based crosslinking agents and other crosslinking agents may also be used. In the embodiment using the isocyanate-based crosslinking agent, the amount of the isocyanate-based crosslinking agent may be, for example, 0.005 parts by weight or more, 0.01 parts by weight or more, and 0.03 parts by weight or more, based on 100 parts by weight of the polymer (a). The amount of the isocyanate-based crosslinking agent used may be, for example, 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1 part by weight or less, 0.80 parts by weight or less, 0.60 parts by weight or less, 0.30 parts by weight or less, 0.10 parts by weight or less, or 0.08 parts by weight or less, based on 100 parts by weight of the polymer (a).

In order to allow the crosslinking reaction to proceed more efficiently, a crosslinking catalyst may be used. Examples of the crosslinking catalyst include metal-based crosslinking catalysts such as tetra-n-butyl titanate, tetra-isopropyl titanate, iron acetylacetonate (Japanese text: ナーセム: ニ iron), butyltin oxide, and dioctyltin dilaurate. Among them, tin-based crosslinking catalysts such as dioctyltin dilaurate are preferable. The amount of the crosslinking catalyst used is not particularly limited. The crosslinking catalyst may be used in an amount of, for example, about 0.0001 part by weight or more, about 0.001 part by weight or more, about 0.005 part by weight or more, or about 1 part by weight or less, about 0.1 part by weight or less, or about 0.05 part by weight or less, based on 100 parts by weight of the polymer (A).

The adhesive composition for forming the adhesive layer may contain a compound that causes keto-enol tautomerism as a crosslinking retarder as desired. For example, in an adhesive composition containing an isocyanate-based crosslinking agent or an adhesive composition which can be used by blending an isocyanate-based crosslinking agent, a compound which causes keto-enol tautomerism can be preferably used. This can exert an effect of extending the pot life of the adhesive composition.

As the compound that generates keto-enol tautomerism, various β -dicarbonyl compounds can be used. Specific examples thereof include β -diketones such as acetylacetone and 2, 4-hexanedione; acetoacetic acid esters such as methyl acetoacetate and ethyl acetoacetate; propionyl acetates such as propionyl ethyl acetate; isobutyryl acetate esters such as isobutyryl ethyl acetate; malonic esters such as methyl malonate and ethyl malonate; and the like. Among these, acetylacetone and acetoacetates are suitable compounds. The compound which causes keto-enol tautomerism may be used alone in 1 kind or in combination of 2 or more kinds.

The amount of the compound which causes keto-enol tautomerism may be, for example, 0.1 part by weight or more and 20 parts by weight or less, and usually 0.5 part by weight or more and 15 parts by weight or less, is suitable, for example, 1 part by weight or more and 10 parts by weight or less, and may be 1 part by weight or more and 5 parts by weight or less, with respect to 100 parts by weight of the polymer (a).

(silane coupling agent)

The adhesive layer of the adhesive sheet disclosed herein may contain a silane coupling agent as desired. By using the silane coupling agent, the peel strength of the adhesive sheet from an adherend (e.g., a glass plate) can be improved. The adhesive layer containing a silane coupling agent may be suitably formed using an adhesive composition containing a silane coupling agent. In the pressure-sensitive adhesive composition, the silane coupling agent is preferably contained in a free form in the pressure-sensitive adhesive composition from the viewpoint of suppressing gelation and the like. In addition, in some aspects, the silane coupling agent is preferably contained in a free form in the adhesive layer of the adhesive sheet disclosed herein. The silane coupling agent contained in the adhesive layer in this manner can contribute to improvement of the peeling force with high efficiency. It should be noted that the term "free form" as used herein means: the silane coupling agent is not chemically bonded to the adhesive composition or other components contained in the adhesive layer.

Examples of the silane coupling agent include silicon compounds having an epoxy structure such as 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane and 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane; amino group-containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane and N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane; 3-chloropropyltrimethoxysilane; an acetoacetyl-containing trimethoxysilane; (meth) acryloyl group-containing silane coupling agents such as 3-acryloyloxypropyltrimethoxysilane and 3-methacryloyloxypropyltriethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane; and the like. In some cases, the above-described effect can be more preferably exerted by using a silane coupling agent having a trialkoxysilyl group. Among them, 3-glycidoxypropyltrimethoxysilane and acetoacetyl-containing trimethoxysilane are exemplified as preferable silane coupling agents.

The amount of the silane coupling agent used is not particularly limited, and may be set so as to obtain a desired effect. In some embodiments, the amount of the silane coupling agent to be used may be, for example, 0.001 parts by weight or more per 100 parts by weight of the polymer (a), and from the viewpoint of obtaining higher effects, may be 0.01 parts by weight or more, may be 0.05 parts by weight or more, and may be 0.1 parts by weight or more. From the viewpoint of suppressing gelation of the adhesive composition, the amount of the silane coupling agent to be used is usually preferably 3 parts by weight or less, and may be 1 part by weight or less, and may be 0.5 part by weight or less, based on 100 parts by weight of the polymer (a).

(photopolymerization initiator)

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet disclosed herein may contain a photopolymerization initiator as necessary for the purpose of improving or imparting photocurability or the like. As the photopolymerization initiator, as with the photopolymerization initiators exemplified as those usable for synthesizing the polymer (a), ketal-based photopolymerization initiators, acetophenone-based photopolymerization initiators, benzoin ether-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, α -keto-alcohol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzil-based photopolymerization initiators, benzophenone-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and the like can be used. The photopolymerization initiator may be used singly or in any suitable combination of two or more.

Specific examples of the ketal-based photopolymerization initiator include: 2, 2-dimethoxy-1, 2-diphenylethan-1-one, and the like.

Specific examples of the acetophenone-based photopolymerization initiator include: 1-hydroxycyclohexyl-phenyl-ketone, 4-phenoxydichloroacetophenone, 4-tert-butyl-dichloroacetophenone, 1- [4- (2-hydroxyethoxy) -phenyl ] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, methoxyacetophenone and the like.

Specific examples of the benzoin ether-based photopolymerization initiator include: benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether, and substituted benzoin ethers such as benzoin methyl ether.

Specific examples of the acylphosphine oxide-based photopolymerization initiator include: bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4, 6-trimethylbenzoyl) -2, 4-di-n-butoxyphenylphosphine oxide, 2,4, 6-trimethylbenzoyl diphenylphosphine oxide, bis (2, 6-dimethoxybenzoyl) -2,4, 4-trimethylpentylphosphine oxide, and the like.

Specific examples of the α -ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) phenyl ] -2-methylpropan-1-one. Specific examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalenesulfonyl chloride and the like. Specific examples of the optically active oxime-based photopolymerization initiator include 1-phenyl-1, 1-propanedione-2- (o-ethoxycarbonyl) -oxime and the like. Specific examples of the benzoin-based photopolymerization initiator include benzoin and the like. Specific examples of the benzil-based photopolymerization initiator include benzil and the like.

Specific examples of the benzophenone-based photopolymerization initiator include: benzophenone, benzoylbenzoic acid, 3' -dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α -hydroxycyclohexyl phenyl ketone and the like.

Specific examples of the thioxanthone-based photopolymerization initiator include: thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2, 4-dimethylthioxanthone, isopropylthioxanthone, 2, 4-dichlorothioxanthone, 2, 4-diethylthioxanthone, isopropylthioxanthone, 2, 4-diisopropylthioxanthone, dodecylthioxanthone, and the like.

The content of the photopolymerization initiator in the pressure-sensitive adhesive layer is not particularly limited, and may be set so as to exhibit a desired effect as appropriate. In some embodiments, the content of the photopolymerization initiator may be, for example, about 0.005 parts by weight or more, and usually 0.01 parts by weight or more is suitable, and preferably 0.05 parts by weight or more, and may be 0.10 parts by weight or more, may be 0.15 parts by weight or more, and may be 0.20 parts by weight or more, based on 100 parts by weight of the polymer (a) contained in the pressure-sensitive adhesive layer. By increasing the content of the photopolymerization initiator, the photocurability of the adhesive layer tends to be improved. The content of the photopolymerization initiator is usually preferably 10 parts by weight or less, more preferably 7 parts by weight or less, further preferably 5 parts by weight or less, further preferably 3 parts by weight or less, further preferably 2 parts by weight or less, further preferably 1 part by weight or less, based on 100 parts by weight of the polymer (a). If the content of the photopolymerization initiator is too large, the pressure-sensitive adhesive sheet may be advantageous from the viewpoint of improving storage stability (e.g., stability against photodegradation) of the pressure-sensitive adhesive sheet.

The adhesive layer containing a photopolymerization initiator can be typically formed by using an adhesive composition (e.g., solvent-based adhesive composition) containing the photopolymerization initiator. The adhesive composition containing a photopolymerization initiator can be prepared, for example, by mixing other components used in the composition and the photopolymerization initiator. In addition, when the adhesive composition is prepared using the (photopolymerizable) polymer (a) (for example, the acrylic polymer (a)) synthesized in the presence of the photopolymerization initiator, a residue (unreacted product) of the photopolymerization initiator used in synthesizing the polymer (a) may be used as a part or all of the photopolymerization initiator contained in the adhesive layer. The same applies to the case where an acrylic oligomer obtained by synthesis in the presence of a photopolymerization initiator is used as the acrylic oligomer used as needed. The adhesive layer disclosed herein can be preferably formed using an adhesive composition prepared by newly adding the photopolymerization initiator in the above-described amount to other components, from the viewpoint of ease of manufacturing management.

The pressure-sensitive adhesive layer in the technology disclosed herein may contain, as necessary, leveling agents, plasticizers, softening agents, colorants (dyes, pigments, and the like), fillers, antistatic agents, anti-aging agents, ultraviolet absorbers, antioxidants, light stabilizers, preservatives, and other known additives that can be used in pressure-sensitive adhesives, within a range that does not significantly impair the effects of the present invention. In the case of an adhesive sheet for use in applications where silicone is not desired (e.g., electronic device manufacturing applications), it is desirable to avoid the use of silicone-based additives (e.g., silicone-based leveling agents and defoaming agents).

< formation of adhesive layer >

The adhesive layer constituting the adhesive sheet disclosed herein may be a cured layer of an adhesive composition containing the corresponding components. That is, the pressure-sensitive adhesive layer can be formed by applying (for example, coating) the pressure-sensitive adhesive composition on an appropriate surface, and then suitably performing curing treatment such as drying (for example, heat drying), crosslinking (for example, crosslinking by the reaction of the above-mentioned crosslinking agent), cooling, and the like. When 2 or more curing treatments are carried out, they may be carried out simultaneously or in stages.

In some embodiments, the adhesive composition contains at least the polymer (a) described above. A preferred embodiment of the adhesive composition contains an acrylic polymer (a) as the polymer (a). The adhesive composition may contain the polymer (a) as a precursor thereof. The pressure-sensitive adhesive composition preferably contains the polymer (a) as described above and the photoreactive monomer (B) as described above. The above-mentioned photoreactive monomer (B) preferably contains a compound B1 having a cyclic structure and 2 or more ethylenically unsaturated groups in the molecule. The average molecular weight of the compound B1 per the ethylenically unsaturated group is preferably 100g/mol or more.

The form of the pressure-sensitive adhesive composition is not particularly limited, and for example, it may be a water dispersion type pressure-sensitive adhesive composition in which a pressure-sensitive adhesive (pressure-sensitive adhesive component) is dispersed in water; a solvent-based adhesive composition containing an adhesive in an organic solvent; hot melt adhesive compositions which form an adhesive when applied in a molten state under heating and cooled to around room temperature, and the like; various forms are known. From the viewpoint of ease of preparation of the adhesive composition, ease of formation of the adhesive layer, and the like, a solvent-based adhesive composition may be preferably used in some embodiments. The solvent-based adhesive composition can be preferably prepared by using the polymer (a) as a solution-polymerized polymer based on a monomer component.

The application of the adhesive composition can be carried out using a conventional coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, or a spray coater. In the psa sheet having the form of a support, as a method for providing a psa layer on a support, a direct method may be used in which a psa composition is directly applied to the support to form a psa layer, or a transfer method may be used in which a psa layer formed on a release surface is transferred to a support.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and may be, for example, about 3 μm to 500 μm. From the viewpoint of impact resistance, the thickness of the pressure-sensitive adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more in some embodiments. In some embodiments, the thickness of the pressure-sensitive adhesive layer may be, for example, 200 μm or less, and is preferably 120 μm or less, may be 100 μm or less, may be 70 μm or less, may be 50 μm or less, and may be 35 μm or less, from the viewpoint of suppressing deformation of the pressure-sensitive adhesive layer. According to the pressure-sensitive adhesive sheet disclosed herein, in the form of having a pressure-sensitive adhesive layer having a thickness of, for example, 70 μm or less, it is possible to form a joint having high deformation resistance and high impact resistance.

< support >

The pressure-sensitive adhesive sheet of some embodiments may be in the form of a support-attached pressure-sensitive adhesive sheet including a support joined to a pressure-sensitive adhesive layer. The material of the support is not particularly limited, and may be appropriately selected depending on the purpose of use, the mode of use, and the like of the adhesive sheet. Non-limiting examples of supports that can be used include: resin films such as polyolefin films mainly composed of polyolefins such as polypropylene and ethylene-propylene copolymers, polyester films mainly composed of polyesters such as polyethylene terephthalate and polybutylene terephthalate, and polyvinyl chloride films mainly composed of polyvinyl chloride; foam sheets formed of foams such as polyurethane foam, polyethylene foam, and polychloroprene foam; woven and nonwoven fabrics formed from various fibrous materials (natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon, and semisynthetic fibers such as acetate) alone or in a blend; paper such as japanese paper, fine paper, kraft paper, crepe paper, and the like; metal foils such as aluminum foil and copper foil; and the like. The support may be a composite support. Examples of the support having such a composite structure include a metal layer (e.g., a metal foil, a continuous or discontinuous metal sputtering layer, a metal deposition layer, a metal plating layer, etc.), a support having a structure in which a metal oxide layer and the resin film are laminated, and a resin sheet reinforced with inorganic fibers such as glass cloth. The support may be an optical member (for example, an optical film) described later, or may be a transparent member formed of a transparent material (for example, a resin material having transparency, glass, or the like).

As the support of the adhesive sheet disclosed herein, various films (hereinafter, also referred to as support films) can be preferably used. The support film may be a porous film such as a foam film or a nonwoven fabric sheet, a non-porous film, or a film having a structure in which a porous layer and a non-porous layer are laminated. In some embodiments, as the support film, a film containing a (self-supporting or independent) resin film capable of independently maintaining the shape as a base film can be preferably used. The term "resin film" as used herein refers to a non-porous structure, and typically refers to a resin film substantially free of bubbles (non-porous). Therefore, the resin film is a concept that is distinguished from a foam film and a nonwoven fabric. The resin film may have a single-layer structure or a multilayer structure (for example, a three-layer structure) of two or more layers.

As the resin material constituting the resin film, for example, resins such as polyesters, polyolefins, polycycloolefins derived from monomers having an aliphatic ring structure such as a norbornene structure, Polyamides (PA) such as nylon 6, nylon 66 and partially aromatic polyamides, Polyimides (PI), Polyamideimides (PAI), Polyetheretherketones (PEEK), Polyethersulfones (PES), polyphenylene sulfides (PPS), Polycarbonates (PC), Polyurethanes (PU), ethylene-vinyl acetate copolymers (EVA), fluororesins such as polystyrene, polyvinyl chloride, polyvinylidene chloride and Polytetrafluoroethylene (PTFE), acrylic resins such as polymethyl methacrylate, cellulosic polymers such as diacetylcellulose and triacetylcellulose, vinyl butyral polymers, acrylate polymers, polyoxymethylene polymers, and epoxy polymers can be used. The resin film may be formed using a resin material containing one kind of such resin alone, or may be formed using a resin material obtained by mixing two or more kinds of resins together. The resin film may be unstretched or stretched (for example, uniaxially stretched or biaxially stretched).

Preferred examples of the resin material constituting the resin film include a polyester resin, a PPS resin, and a polyolefin resin. The polyester resin is a resin containing a polyester in a proportion of more than 50% by weight. Similarly, the PPS resin refers to a resin containing PPS in a proportion of more than 50 wt%, and the polyolefin resin refers to a resin containing polyolefin in a proportion of more than 50 wt%.

As the polyester resin, typically, a polyester resin containing as a main component a polyester obtained by polycondensation of a dicarboxylic acid and a diol can be used. Specific examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polybutylene naphthalate.

As the polyolefin resin, one kind of polyolefin may be used alone, or two or more kinds of polyolefins may be used in combination. The polyolefin may be, for example, a homopolymer of an α -olefin, a copolymer of two or more α -olefins, a copolymer of one or two or more α -olefins with another vinyl monomer, or the like. Specific examples thereof include ethylene-propylene copolymers such as Polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene and ethylene-propylene rubber (EPR), ethylene-propylene-butene copolymers, ethylene-vinyl alcohol copolymers and ethylene-ethyl acrylate copolymers. Both Low Density (LD) polyolefins and High Density (HD) polyolefins may be used. Examples of the polyolefin resin film include an unstretched polypropylene (CPP) film, a biaxially stretched polypropylene (OPP) film, a Low Density Polyethylene (LDPE) film, a Linear Low Density Polyethylene (LLDPE) film, a Medium Density Polyethylene (MDPE) film, a High Density Polyethylene (HDPE) film, a Polyethylene (PE) film obtained by blending two or more types of Polyethylenes (PE), a PP/PE blend film obtained by blending polypropylene (PP) and Polyethylene (PE), and the like.

Specific examples of the resin film which can be preferably used as the support include a PET film, a PEN film, a PPS film, a PEEK film, a CPP film, and an OPP film. From the viewpoint of strength, preferable examples include a PET film, a PEN film, a PPS film, and a PEEK film. From the viewpoint of availability, dimensional stability, optical properties, and the like, a PET film is a preferred example.

The resin film may contain, as necessary, known additives such as a light stabilizer, an antioxidant, an antistatic agent, a colorant (dye, pigment, and the like), a filler, a slipping agent, and an antiblocking agent. The amount of the additive to be blended is not particularly limited, and may be appropriately set according to the use of the pressure-sensitive adhesive sheet and the like.

The method for producing the resin film is not particularly limited. For example, conventionally known common resin film forming methods such as extrusion molding, inflation molding, T-die casting molding, calender roll molding, and the like can be suitably used.

The support may be a support film substantially composed of such a resin film. The support may be a support film containing an auxiliary layer in addition to the resin film. The auxiliary layer may be disposed on the pressure-sensitive adhesive layer side of the resin film, may be disposed on the opposite side of the pressure-sensitive adhesive layer, or may be disposed on both sides of the resin film. Examples of the auxiliary layer include an optical property adjusting layer (for example, a colored layer and an antireflection layer), a decorative layer (for example, a printed layer, a laminated layer, a continuous or discontinuous metal oxide layer, or the like) for giving a desired appearance to a support or an adhesive sheet, a conductive layer, an antistatic layer, an undercoat layer, and a release layer.

The thickness of the support is not particularly limited, and may be selected according to the purpose of use, the mode of use, and the like of the adhesive sheet. The thickness of the support may be, for example, 1000 μm or less, 500 μm or less, 100 μm or less, 70 μm or less, 50 μm or less, 25 μm or less, 10 μm or less, and 5 μm or less. When the thickness of the support is reduced, the flexibility of the pressure-sensitive adhesive sheet and the following property to the surface shape of the adherend tend to be improved. The thickness of the support may be, for example, 2 μm or more, and may be more than 5 μm or more than 10 μm from the viewpoint of workability, processability, and the like. In some embodiments, the thickness of the support may be, for example, 20 μm or more, 35 μm or more, and 55 μm or more.

The surface of the support on the side to be bonded to the pressure-sensitive adhesive layer may be subjected to conventionally known surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, coating with a primer (primer), and antistatic treatment, as required. Such surface treatment may be treatment for improving adhesion between the support and the adhesive layer, in other words, anchoring property of the adhesive layer to the support. The composition of the primer is not particularly limited, and may be appropriately selected from known ones. The thickness of the undercoat layer is not particularly limited, and is usually about 0.01 μm to 1 μm, preferably about 0.1 μm to 1 μm.

In the single-sided psa sheet with a support, a surface of the support opposite to the side to be bonded to the psa layer (hereinafter also referred to as the back surface) may be subjected to conventionally known surface treatments such as a peeling treatment, a treatment for improving adhesiveness or adhesiveness, and an antistatic treatment, if necessary. For example, the back surface of the support is subjected to a surface treatment with a release treatment agent, whereby the unwinding force of the adhesive sheet wound in a roll shape can be reduced. Examples of the release treatment agent include silicone release treatment agents, long-chain alkyl release treatment agents, olefin release treatment agents, fluorine release treatment agents, fatty acid amide release treatment agents, molybdenum sulfide, and silica powder.

< method for producing laminate >

The pressure-sensitive adhesive sheet disclosed herein can be preferably used in such a manner that the pressure-sensitive adhesive sheet is attached to an adherend by a method including photocuring the pressure-sensitive adhesive layer after the pressure-sensitive adhesive sheet is attached to the adherend. By attaching the pressure-sensitive adhesive sheet to an adherend, an adherend on which the pressure-sensitive adhesive sheet is laminated can be formed. By photocuring the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, a laminate comprising the pressure-sensitive adhesive sheet with the cured pressure-sensitive adhesive layer and the adherend can be obtained. Therefore, according to this specification, there is provided a laminate manufacturing method including, in order: any of the pressure-sensitive adhesive sheets disclosed herein is adhered to an adherend, and the pressure-sensitive adhesive layer is photo-cured by irradiating the pressure-sensitive adhesive sheet with ultraviolet light.

< use >

The adhesive sheet disclosed herein can be used for fixing, joining, molding, decorating, protecting, supporting, and the like of members constituting various articles. The material constituting at least the surface of the member may be, for example, glass such as alkali glass or alkali-free glass; metal materials such as stainless steel (SUS) and aluminum; resin materials such as acrylic resins, ABS resins, polycarbonate resins, and polystyrene resins; and the like. The member may be, for example, a member constituting various Portable devices (Portable apparatuses), automobiles, home electric appliances, and the like. In the above members, the surface to which the adhesive sheet is attached may be a coated surface based on a coating material such as an acrylic, polyester, alkyd, melamine, urethane, acid epoxy crosslinking, or a composite thereof (for example, acrylic melamine or alkyd melamine), or a plated surface such as a galvanized steel sheet. The member may be any supporting film exemplified as a material that can be used for the support (for example, a resin film, a supporting film having a continuous or discontinuous inorganic layer (which may be a metal layer, a metal oxide layer, or the like) on the resin film). The pressure-sensitive adhesive sheet disclosed herein may be, for example, a component of a member with a pressure-sensitive adhesive sheet in which the member is bonded to at least one surface of a pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive layer.

As an example of preferable applications, optical applications are cited. More specifically, the pressure-sensitive adhesive sheet disclosed herein can be preferably used, for example, as a pressure-sensitive adhesive sheet for optical use used for applications of bonding optical members (for bonding optical members), and applications of manufacturing products (optical products) using the optical members.

The optical member is a member having optical characteristics (e.g., polarization, light refraction, light scattering, light reflection, light transmittance, light absorption, light diffraction, optical rotation, visibility, etc.). The optical member is not particularly limited as long as it is a member having optical characteristics, and examples thereof include a member constituting a device (optical device) such as a display device (image display device) or an input device, and a member used for the device, and examples thereof include a polarizing plate, a wavelength plate, a retardation plate, an optical compensation film, a luminance improvement film, a light guide plate, a reflection film, an antireflection film, a Hard Coat (HC) film, an impact absorption film, an antifouling film, a photochromic film, a light control film, a transparent conductive film (ITO film), a design film, a decorative film, a surface protection plate, a prism, a lens, a color filter, a transparent substrate, and a member in which these are laminated (these may be collectively referred to as a "functional film"). The "plate" and the "film" described above each include a plate-like, film-like, sheet-like form, and the like, and for example, the "polarizing film" includes a "polarizing plate" and a "polarizing plate".

Examples of the display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper. The input device may be a touch panel.

The optical member is not particularly limited, and examples thereof include members (e.g., sheet-like, film-like, and plate-like members) formed of glass, acrylic resin, polycarbonate, polyethylene terephthalate, a metal film, and the like. The term "optical member" as used herein includes a member (e.g., design film, decorative film, surface protection film) which plays a role of decoration and protection while maintaining visibility of a display device and an input device.

The method of bonding the optical members using the adhesive sheet disclosed herein is not particularly limited, and examples thereof include (1) a method of bonding the optical members to each other via the adhesive sheet disclosed herein, (2) a method of bonding the optical members to members other than the optical members via the adhesive sheet disclosed herein, and (3) a method of bonding the adhesive sheet to the optical members or members other than the optical members while including the optical members. In the embodiment (3), the pressure-sensitive adhesive sheet including the optical member may be a pressure-sensitive adhesive sheet in which the support is an optical member (e.g., an optical film), for example. The pressure-sensitive adhesive sheet including the optical member as a support in this manner can also be considered to be a pressure-sensitive adhesive optical member (e.g., a pressure-sensitive adhesive optical film). In addition, when the pressure-sensitive adhesive sheet disclosed herein is a pressure-sensitive adhesive sheet of a type having a support and the functional film is used as the support, the pressure-sensitive adhesive sheet disclosed herein may be considered to be an "adhesive functional film" having a pressure-sensitive adhesive layer disclosed herein on at least one side of the functional film.

The matters disclosed in the present specification include the following.

(1) An adhesive sheet comprising an adhesive layer,

the adhesive layer contains a polymer (A) and a photoreactive monomer (B),

the above-mentioned photoreactive monomer (B) comprises a compound B1 having 2 or more ethylenically unsaturated groups,

in the above-mentioned compound B1, the molecular weight (functional group equivalent) per the ethylenically unsaturated group is 100g/mol or more on average.

(2) The adhesive sheet according to the item (1), wherein the compound B1 contains a ring structure in a molecule.

(3) The adhesive sheet according to the item (2), wherein the compound B1 contains at least one structure selected from the group consisting of a bisphenol a structure, a bisphenol F structure and a bisphenol E structure in a molecule.

(4) The adhesive sheet according to the item (2) or (3), wherein the compound B1 contains an aliphatic ring structure as the ring structure.

(5) The adhesive sheet according to any one of the above (1) to (4), wherein the compound B1 contains at least one structure selected from the group consisting of a hydroxyl group and an amino group in a molecule.

(6) The adhesive sheet according to any one of the items (1) to (5), wherein the content of the compound B1 in the adhesive layer is 0.5 parts by weight or more and 60 parts by weight or less based on 100 parts by weight of the polymer (a).

(7) The adhesive sheet according to any one of the above (2) to (5), wherein the adhesive layer contains, as the photoreactive monomer (B), the compound B1 and a compound B2 having 2 or more functional groups and no ring structure in a molecule.

(8) The adhesive sheet according to the item (7), wherein the functional group equivalent of the compound B2 is smaller than the functional group equivalent of the compound B1.

(9) The adhesive sheet according to the above (7) or (8), wherein the compound B2 has a functional group equivalent of 400g/mol or less.

(10) The adhesive sheet according to any one of the above (7) to (9), wherein the content of the compound B2 in the adhesive layer is 25 parts by weight or less based on 100 parts by weight of the polymer (a).

(11) The adhesive sheet according to any one of the items (1) to (10), wherein the content of the photoreactive monomer (B) in the adhesive layer is 1 part by weight or more and 80 parts by weight or less with respect to 100 parts by weight of the polymer (a).

(12) The adhesive sheet according to any one of the above (1) to (11), wherein the polymer (A) is an acrylic polymer.

(13) The adhesive sheet according to the item (12), wherein the monomer component constituting the acrylic polymer contains a monomer having a nitrogen atom-containing ring.

(14) The adhesive sheet according to any one of the above (1) to (13), wherein the glass transition temperature of the polymer (A) is-45 ℃ or higher and lower than 0 ℃.

(15) The adhesive sheet according to any one of the above (1) to (14), wherein the adhesive layer is crosslinked by a crosslinking agent.

(16) The adhesive sheet according to any one of the above (1) to (15), wherein the adhesive layer contains a photopolymerization initiator.

(17) The adhesive sheet according to any one of the above (1) to (14), wherein the adhesive layer contains a silane coupling agent.

(18) The adhesive sheet according to any one of (1) to (17), wherein the tensile modulus measured by the tensile test is 3.0MPa or more.

(19) The adhesive sheet according to any one of the above (1) to (18), wherein the impact resistance measured by the shear impact test is 2.0J/(10mm)²The above.

(20) The adhesive sheet according to any one of the above (1) to (19), wherein a peel strength measured by the peel test is 1.0N/10mm or more.

(21) An adhesive composition comprising a polymer (A) and a photoreactive monomer (B),

(22) The adhesive sheet according to the item (21), wherein the compound B1 contains a ring structure in a molecule.

(23) The adhesive composition according to the item (22), wherein the compound B1 contains at least one structure selected from the group consisting of a bisphenol A structure, a bisphenol F structure and a bisphenol E structure in a molecule.

(24) The adhesive composition according to the item (2) or (23), wherein the compound B1 contains an aliphatic ring structure as the ring structure.

(25) The adhesive composition according to any one of the above (21) to (24), wherein the compound B1 contains at least one structure selected from the group consisting of a hydroxyl group and an amino group in a molecule.

(26) The adhesive composition according to any one of the items (21) to (25), wherein the content of the compound B1 in the adhesive layer is 0.5 parts by weight or more and 60 parts by weight or less based on 100 parts by weight of the polymer (a).

(27) The adhesive composition according to any one of the above (22) to (25), wherein the adhesive layer contains, as the photoreactive monomer (B), the compound B1 and a compound B2 having 2 or more functional groups and no ring structure in a molecule.

(28) The adhesive composition according to the item (27), wherein the equivalent weight of the compound B2 is smaller than the equivalent weight of the compound B1.

(29) The adhesive composition according to the item (27) or (28), wherein the compound B2 has a functional group equivalent of 400g/mol or less.

(30) The adhesive composition according to any one of the items (27) to (29), wherein the content of the compound B2 in the adhesive layer is 25 parts by weight or less based on 100 parts by weight of the polymer (A).

(31) The adhesive composition according to any one of (21) to (30), wherein the content of the photoreactive monomer (B) in the adhesive layer is 1 part by weight or more and 80 parts by weight or less with respect to 100 parts by weight of the polymer (a).

(32) The adhesive composition according to any one of the above (21) to (31), wherein the polymer (A) is an acrylic polymer.

(33) The adhesive composition according to the item (32), wherein the monomer component constituting the acrylic polymer contains a monomer having a nitrogen atom-containing ring.

(34) The adhesive composition according to any one of the above (21) to (33), wherein the glass transition temperature of the polymer (A) is-45 ℃ or higher and lower than 0 ℃.

(35) The adhesive composition according to any one of the above (21) to (34), wherein the adhesive composition contains a crosslinking agent.

(36) The adhesive composition according to any one of the above (21) to (35), wherein the adhesive composition contains a photopolymerization initiator.

(37) The adhesive composition according to any one of the above (21) to (36), wherein the adhesive composition contains a silane coupling agent.

(38) The adhesive composition according to any one of (21) to (37) above, which is used for forming the adhesive layer of the adhesive sheet according to any one of (1) to (20).

(39) A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition according to any one of (21) to (37) above.

(40) An adhesive sheet comprising an adhesive layer,

a tensile modulus of 3.0MPa or more as measured by the tensile test, and an impact resistance of 2.0J/(10mm) as measured by the shear impact test²The above.

(41) The adhesive sheet according to the item (40), wherein the peel strength measured by the peel test is 1.0N/10mm or more.

(42) The adhesive sheet according to any one of (40) to (41) above, wherein the adhesive layer is the adhesive layer according to any one of (1) to (17) above.

(43) The adhesive sheet according to any one of (40) to (42), wherein the adhesive layer is an adhesive layer formed from the adhesive composition according to any one of (21) to (37).

(44) The adhesive composition according to any one of the above (21) to (37), wherein the adhesive composition has a tensile modulus of 3.0MPa or more as measured by the tensile test with respect to an adhesive layer (for example, an adhesive layer having a thickness of 20 μm) formed from the adhesive composition and having a thickness selected from the range of 5 μm to 200 μm (preferably, the range of 15 μm to 25 μm).

(45) The adhesive composition according to the item (44), wherein the adhesive composition has an impact resistance of 2.0J/(10mm) as measured by the shear impact test on the adhesive layer having the thickness formed from the adhesive composition²The above.

(46) The pressure-sensitive adhesive composition of (44) or (45), wherein the pressure-sensitive adhesive composition has a peel strength of 1.0N/10mm or more as measured by the peel test for the pressure-sensitive adhesive layer having the thickness formed from the pressure-sensitive adhesive composition.

(47) A film member with an adhesive sheet, comprising: the adhesive sheet according to any one of (1) to (20) and (40) to (43) above, and a film member bonded to the adhesive layer.

(48) A method of manufacturing a laminate, comprising in order:

bonding the pressure-sensitive adhesive sheet according to any one of (1) to (20) and (40) to (43) to an adherend, and

the pressure-sensitive adhesive sheet is irradiated with ultraviolet rays to photocure the pressure-sensitive adhesive layer.

The present invention will be described with reference to examples, but the present invention is not intended to be limited to the examples. In the following description, "parts" and "%" are by weight unless otherwise specified.

< Synthesis of Polymer (A) >

(Polymer P1)

In a reaction vessel equipped with a condenser tube, a nitrogen inlet tube, a thermometer and a stirring device, 60 parts of N-Butyl Acrylate (BA), 6 parts of cyclohexyl acrylate (CHA), 18 parts of N-vinyl-2-pyrrolidone (NVP), 1 part of isostearyl acrylate (iSTA) and 15 parts of 4-hydroxybutyl acrylate (4HBA), 0.085 parts of α -thioglycerol as a chain transfer agent and 122 parts of ethyl acetate as a polymerization solvent were charged as monomer components, and 0.2 parts of 2, 2' -Azobisisobutyronitrile (AIBN) as a thermal polymerization initiator was charged and solution polymerization was carried out in a nitrogen atmosphere, thereby obtaining a solution of polymer P1. The weight average molecular weight (Mw) of the polymer P1 was 30 ten thousand. The Tg of the polymer P1, calculated from the composition of the monomer components described above, was-33 ℃.

(Polymer P2)

In a reaction vessel equipped with a condenser tube, a nitrogen inlet tube, a thermometer and a stirrer, 64.5 parts of BA, 6 parts of CHA, 9.6 parts of NVP, 5 parts of iSTA and 14.9 parts of 4HBA as monomer components, 0.07 part of α -thioglycerol as a chain transfer agent and 122 parts of ethyl acetate as a polymerization solvent were charged, and 0.2 part of AIBN as a thermal polymerization initiator was charged to conduct solution polymerization in a nitrogen atmosphere, thereby obtaining a solution of polymer P2. The Mw of polymer P2 was 60 ten thousand. The Tg of the polymer P2, calculated from the composition of the monomer components described above, was-39 ℃.

< preparation of adhesive composition >

(example 1)

To the solution of the polymer P1 thus obtained, an isocyanate-based crosslinking agent X1 (trimethylolpropane/xylylene diisocyanate adduct (product name: TAKENATE D-110N, solid content concentration: 75%) was added in an amount of 0.05 parts by solid content basis, based on 100 parts of the monomer component used for the preparation of the solution), dioctyl tin dilaurate (product name: EMBLIZER OL-1, product name: Tokyo Fine Chemical Co., Ltd., product name: Ltd.) as a crosslinking accelerator, 0.01 part of acetylacetone as a crosslinking retarder, 0.3 part of 3-glycidyloxypropyltrimethoxysilane (product name: KBM-403, product name: shin-Etsu Chemical industries), 8 parts of dipentaerythritol hexaacrylate (product name: A-DPH ") as a photoreactive monomer, and tricyclodecane dimethanol (product name: KBM-403, product name: shin-Dow Chemical industries, products industries, Ltd.) as a new village Chemical industries, to 100 parts of the monomer component used for the preparation of the solution, Trade name "a-DCP") 12 parts, and 1-hydroxycyclohexyl-phenyl-ketone (product name: omnirad 184)0.72 parts, and uniformly mixed to prepare the solvent-based adhesive composition of example 1.

(examples 2 to 3,5 to 12)

Solvent-based adhesive compositions of the respective examples were prepared in the same manner as the solvent-based adhesive composition of example 1 except that the kind and amount of the photoreactive monomer, the amount of the crosslinking agent, and the amount of the photopolymerization initiator were changed as shown in tables 1 and 2.

(example 4)

A solvent-based adhesive composition of this example was prepared in the same manner as in the preparation of the solvent-based adhesive composition of example 3 except that an isocyanate-based crosslinking agent X2 (trimethylolpropane/tolylene diisocyanate trimer adduct (trade name: Coronate L, manufactured by Tosoh Corp.) was used in place of the isocyanate-based crosslinking agent X1.

(example 13)

A solvent-based adhesive composition of this example was prepared in the same manner as the solvent-based adhesive composition of example 10, except that a solution of polymer P2 was used instead of the solution of polymer P1.

< preparation of pressure-sensitive adhesive sheet >

The solvent-based adhesive compositions of the examples prepared above were applied to the release surface of a 38 μm thick release film R1 (MRF #38, manufactured by mitsubishi resin corporation) having a release surface on one side of the polyester film, and dried at 130 ℃ for 3 minutes to form a photocurable adhesive layer (unsupported double-sided adhesive sheet) having a thickness of 20 μm. The release surface of a release film R2 (MRE #38, manufactured by Mitsubishi resin corporation) having a thickness of 38 μm and having one side of a polyester film as a release surface was bonded to the surface of the pressure-sensitive adhesive layer for protection. Thus, a laminate sheet was obtained in which the release film R1, the unsupported double-sided adhesive sheet, and the release film R2 were sequentially laminated.

< measurement and evaluation >

The obtained adhesive sheet was subjected to the following measurement and evaluation.

(1) Determination of tensile modulus

Using a high-pressure mercury lamp inIlluminance 300mW/cm²And a cumulative light amount of 3000mJ/cm²The laminates (laminates each having a non-supporting pressure-sensitive adhesive layer sandwiched between 2 transparent release films) of each example were irradiated with ultraviolet rays under the conditions of (1) and cured at 50 ℃ for 48 hours, and then the laminates were cut into a size of 10mm in width and 150mm in length. The pressure-sensitive adhesive layer was exposed by peeling the release films R1 and R2 under an atmosphere of 23 ℃ and 50% RH, a tensile test of the test piece was performed using a tensile tester (manufactured by Minebea, Universal tensile compression tester, apparatus name "tensile compression tester, TCM-1 kNB") under conditions of a chuck pitch of 120mm and a tensile speed of 50 mm/min to obtain an S-S curve, and a tensile modulus [ MPa ] was calculated from an initial slope (a slope in a range where an elastic deformation region, specifically, a displacement of the S-S curve is less than about 5%)]. The measurement was performed 3 times (i.e., n is 3), and the arithmetic mean values thereof are shown in tables 1 and 2.

(2) Determination of impact resistance

The shear impact test was performed using a pendulum type bonding shear impact tester according to JIS K6855. As the measurement samples, the following samples were used: the laminated sheets of the respective examples were cut into a 10mm square, the release film R1 was peeled off to expose the first surface of the pressure-sensitive adhesive layer, the first surface was bonded to the center of a chemically tempered glass plate (manufactured by Corning) having a thickness of 1.7mm and a 25mm square, and after that, the release film R2 was peeled off to bond the second surface of the pressure-sensitive adhesive layer to the center of a stainless steel plate (SUS304BA plate) having a thickness of 40mm square and pressure-bonded under a load of 5N for 10 seconds, followed by autoclave treatment (50 ℃, 0.5MPa, 15 minutes) at 300mW/cm using a mercury lamp with a high illuminance for 300mW/cm²And a cumulative light amount of 3000mJ/cm²The glass plate was irradiated with ultraviolet rays under the conditions described above, and then aged at 50 ℃ for 48 hours, thereby obtaining a sample.

The measurement sample was fixed so that the lower side of the stainless steel plate was positioned, and the absorption energy [ J ] when the outer peripheral side surface of the glass plate was subjected to hammering under conditions of hammering energy of 2.75J and hammering speed (impact speed) of 3.5 m/sec was measured in an environment of 23 ℃ and 50% RH]Thus, the impact resistance [ J/(10mm)²]. The measurement was carried out 3 times, and tables 1 and 2 show the resultsThe arithmetic mean.

(3) Peel strength

The laminated sheets of the respective examples were cut into a size of 10mm in width and 150mm in length to prepare test pieces, the first surface of the adhesive layer in the test pieces was pressure-bonded to a glass plate (alkali glass plate manufactured by Songlanzi industries, Ltd., manufactured by float method, 1.35mm in thickness, green plate edge ground) by reciprocating a 2kg rubber roller once, and were subjected to autoclave treatment (50 ℃, 0.5MPa, 15 minutes) and then to an illuminance of 300mW/cm using a high pressure mercury lamp²And a cumulative light amount of 3000mJ/cm²Under the conditions (3) described above, ultraviolet rays were irradiated from the glass plate side. After this was aged at 50 ℃ for 48 hours, the peel strength of the test piece when the test piece was peeled from the glass plate under conditions of a peel angle of 180 degrees and a tensile rate of 60 mm/min was measured at 23 ℃ and 50% RH using a tensile tester (manufactured by Minebea, Universal tensile compression tester, apparatus name "tensile compression tester, TCM-1 kNB"). The measurement was performed 3 times, and the arithmetic mean values thereof are shown in tables 1 and 2.

The haze values of the pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets of examples 1,6, 8 and 11 were measured by the above-described method and were about 0.5% or less. The adhesive layers of the adhesive sheets of examples 6 and 8 exhibited particularly good transparency.

[ Table 1]

TABLE 1

[ Table 2]

TABLE 2

The photoreactive monomers used in examples 1 to 13 are as follows. In tables 1 and 2, the photoreactive monomers are shown in short.

DPHA: dipentaerythritol hexaacrylate (New Zhongcun chemical industry, trade name "A-DPH", functional group equivalent 96)

A-DCP: dicidol diacrylate (New Zhongcun chemical industry, trade name "A-DCP", functional group equivalent 152)

# 540: bisphenol A diglycidyl ether acrylic acid adduct (Osaka organic chemical industry, trade name "Viscoa # 540", functional group equivalent 250)

R115F: bisphenol A diglycidyl ether acrylic acid adduct (Japan chemical, trade name "KAYARAD R-115F", functional group equivalent 450)

#700 HV: diacrylate ester of bisphenol A ethylene oxide 3.8 mol adduct (trade name "Viscoa #700 HV", functional group equivalent 350, Osaka organic chemical industry)

E3703: amine-modified bisphenol A type epoxy diacrylate (Daicel Ornex Co., Ltd., trade name "EBECRYL 3703", functional group equivalent 425)

APG 400: polypropylene glycol #400 diacrylate (New Zhongcun chemical industry, trade name "APG-400", functional group equivalent 268)

The pressure-sensitive adhesive sheets of examples 1 to 9 shown in table 1 have excellent deformation resistance due to a high tensile modulus and exhibit high impact resistance. On the other hand, the pressure-sensitive adhesive sheets of examples 10, 12 and 13 shown in table 2 had low deformation resistance, and the pressure-sensitive adhesive sheet of example 11 had low peel strength.

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The techniques described in the claims include various modifications and substitutions of the specific examples described above.

Description of the reference numerals

1. 2 pressure-sensitive adhesive sheet

10 adhesive layer

10A one surface (adhesive surface)

10B another surface

20 support body

20A first side

20B second face (Back face)

30. 31, 32 release liner

50 Release liner-attached pressure-sensitive adhesive sheet

70 film component

100 Member with adhesive sheet

Claims

1. An adhesive sheet comprising an adhesive layer,

the adhesive sheet has an elastic modulus of 3.0MPa or more as measured by the tensile test described below and an impact resistance of 2.0J/(10mm) as measured by the shear impact test described below²In the above-mentioned manner,

[ tensile test ]

Under the illumination of 300mW/cm²And a cumulative light amount of 3000mJ/cm²The adhesive layer was irradiated with ultraviolet rays under the conditions of (1) and cured at 50 ℃ for 48 hours, and then the adhesive layer was cut into a size of 10mm in width and 150mm in length to prepare a test piece, and a tensile test of the test piece was carried out under an environment of 23 ℃ and 50% RH at a chuck pitch of 120mm and a tensile speed of 50 mm/min using a tensile tester to obtain a stress-displacement curve, and the elastic modulus [ MPa ] was calculated from the initial slope thereof]，

[ shear impact test ]

The shear impact test was carried out using a pendulum type bonding shear impact tester according to JIS K6855, and as a measurement sample, the following samples were used: after a first surface of the adhesive layer of 10mm square was bonded to a center portion of a chemically strengthened glass plate of 25mm square and 1.7mm thickness, a second surface of the adhesive layer was bonded to a center portion of a SUS304BA plate which is a stainless steel plate of 40mm square and was pressure-bonded under a load of 5N for 10 seconds, and then autoclave treatment was performed at 50 ℃ and 0.5MPa for 15 minutes at an illuminance of 300mW/cm²And a cumulative light amount of 3000mJ/cm²Irradiating ultraviolet rays from the side of the glass plate under the conditions of (1), and then aging at 50 ℃ for 48 hours to thereby obtain a sample,

the measurement sample was fixed so that the lower side of the stainless steel plate was positioned, and the energy absorption [ J ] when the outer peripheral side surface of the glass plate was subjected to hammering at a hammering energy of 2.75J and a hammering speed of 3.5 m/sec was measured in an environment of 23 ℃ and 50% RH]Thus, the impact resistance [ J/(10mm)²]。

2. The adhesive sheet according to claim 1, wherein the peel strength is 1.0N/10mm or more as measured by the following peel test,

[ peeling test ]

A test piece prepared by cutting the adhesive sheet into a size of 10mm in width and 150mm in length was pressure-bonded to a glass plate by reciprocating a 2kg rubber roller once, and was autoclaved at 50 ℃ under 0.5MPa for 15 minutes at an illuminance of 300mW/cm²And a cumulative light amount of 3000mJ/cm²The test piece was cured at 50 ℃ for 48 hours by irradiating ultraviolet rays from the glass plate side under the conditions of (1) and (3), and then the peel strength when the test piece was peeled from the glass plate under the conditions of a peel angle of 180 degrees and a tensile rate of 60 mm/min was measured at 23 ℃ and 50% RH using a tensile tester.

3. The adhesive sheet according to claim 1 or 2, wherein the adhesive layer contains a polymer (a) and a photoreactive monomer (B).

4. The adhesive sheet according to claim 3, wherein the photoreactive monomer (B) comprises a compound B1 having a ring structure and 2 or more ethylenically unsaturated groups in a molecule.

5. The adhesive sheet according to claim 4, wherein the compound B1 has an average molecular weight per one ethylenically unsaturated group of 100g/mol or more.

6. An adhesive sheet comprising an adhesive layer,

the adhesive layer contains a polymer (A) and a photoreactive monomer (B),

the photoreactive monomer (B) comprises a compound B1 having a ring structure and 2 or more ethylenically unsaturated groups in a molecule,

the compound B1 has an average molecular weight per the ethylenically unsaturated group of 100g/mol or more.

7. The adhesive sheet according to claim 6, wherein the elastic modulus measured by the following tensile test is 3.0MPa or more,

[ tensile test ]

Under the illumination of 300mW/cm²And a cumulative light amount of 3000mJ/cm²The pressure-sensitive adhesive layer was irradiated with ultraviolet rays under the conditions of (1) and (2) and cured at 50 ℃ for 48 hours, and then the pressure-sensitive adhesive layer was cut into a size of 10mm in width and 150mm in length to prepare a test piece, and a tensile test of the test piece was performed under an environment of 23 ℃ and 50% RH at a chuck pitch of 120mm and a tensile speed of 50 mm/min using a tensile tester to obtain a stress-displacement curve, and the elastic modulus was calculated from the initial slope.

8. The adhesive sheet according to claim 6 or 7, wherein the impact resistance measured by the following shear impact test is 2.0J/(10mm)²In the above-mentioned manner,

[ shear impact test ]

9. A film member with an adhesive sheet, comprising: the adhesive sheet according to any one of claims 1 to 8, and a film member bonded to the adhesive layer.

10. A method of manufacturing a laminate, comprising in order:

the adhesive sheet according to any one of claims 1 to 8, which is adhered to an adherend, and

the adhesive sheet is irradiated with ultraviolet rays to photocure the adhesive layer.