TW201800528A - Two-sided adhesive sheet and layered body - Google Patents

Abstract

The present invention addresses the problem of providing a two-sided adhesive sheet provided with both contour conforming properties and outgas resistance. The present invention is the two-sided adhesive sheet comprising: a base material layer whereof the light transmittance at a wavelength of 370 nm is 50% or greater; a first adhesive layer provided on one surface side of the base material layer, which is curable after having been adhered thereto; and a second adhesive layer provided on the other surface side of the base material layer, which has a thickness of 5 [mu]m to 75 [mu]m inclusive.

Description

Double-sided adhesive sheet and laminated body

The present invention relates to a double-sided adhesive sheet and a laminated body.

In recent years, a display device such as a liquid crystal display (LCD) and an input device combined with a display device such as a touch panel are widely used in various fields. In the manufacture of such display devices and input devices, a transparent double-sided adhesive sheet is used for the purpose of bonding optical members. For example, a conductive member provided with a transparent electrode film such as ITO (Indium Tin Oxide) and a cover glass, a touch panel, and a display device are laminated on a transparent support, and double-sided adhesive sheets are widely used. .

For example, mobile phone terminal devices such as smartphones etc. are frame printed to hide the electrical circuits inside the device. In this case, a decoration layer is often provided on the peripheral edge portion of the back surface of the cover panel, and the adhesive layer attached on the back surface side of the cover is required to have a property capable of tracking the difference of the decoration layer. In the case where the cover plate is made of resin, the adhesive layer to be bonded on the back surface side of the cover plate must have an adhesive force or a cohesive force against the pressure of the outgas generated from the resin panel. Based on this, there may be a case where both the step-tracking property and the outgassing resistance are required for the adhesive layer. As a means to achieve these problems, a post-curing adhesive layer using ultraviolet irradiation has been proposed (for example, Patent Document 1) .

Furthermore, Patent Document 2 discloses a double-sided adhesive sheet in which a transparent water vapor barrier layer is provided between a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer. Here, by setting the storage elastic modulus of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer within a predetermined range, it is reviewed to provide an adhesive sheet suitable for glass plate bonding.

[Prior technical literature] [Patent Literature]

[Patent Document 1] International Publication No. 2012/032995

[Patent Document 2] Japanese Patent No. 3878386

When the ultraviolet post-curing type adhesive layer described in Patent Document 1 is used, the bonding application is limited to the adherence of the adherend which penetrates ultraviolet rays. For example, when an ultraviolet post-curing type adhesive layer described in Patent Document 1 is used, both the adherends provided on both sides of the adhesive sheet must penetrate ultraviolet rays, which limits the application of bonding.

In addition, the adhesive sheet described in Patent Document 2 was found from the review by the present inventors that the step tracking property is insufficient and the outgassing resistance may be insufficient.

In order to solve the problem of such a conventional technology, the inventors here aim to provide a double-sided adhesive sheet that can also be applied to an adherend adhered by ultraviolet rays, and has both step tracking and resistance to escape. A double-sided adhesive sheet of both sides of gas nature was reviewed.

As a result of intensive research in order to solve the above problems, the present inventors have found that a double-sided adhesive sheet in which a first adhesive layer, a base material layer, and a second adhesive layer are sequentially laminated, and the base material layer is improved. The first adhesive layer and the second adhesive layer with a predetermined UV-ray transmittance and predetermined physical properties are laminated through the substrate layer to obtain a double-sided surface having both step tracking and outgassing resistance. Adhesive sheet. The present inventors discovered that such a double-sided adhesive sheet can also be applied to the adherence of an adherend which does not penetrate ultraviolet rays, and thus completed the present invention.

Specifically, the present invention has the following configuration.

[1] A double-sided adhesive sheet comprising: a base material layer having a light transmittance of 50% or more at a wavelength of 370 nm; a first adhesive layer provided on one side of the base material layer and capable of being cured after bonding; and The second adhesive layer is provided on the other side of the base material layer and has a thickness of 5 μm or more and 75 μm or less.

[2] The double-sided adhesive sheet according to [1], wherein the first adhesive layer is an adhesive layer having an active energy ray-curing ability.

[3] The double-sided adhesive sheet according to any one of [1] or [2], wherein the thickness of the first adhesive layer is 50 μm or more and 250 μm or less.

[4] The double-sided adhesive sheet according to any one of [1] to [3], wherein the first adhesive layer is a decorative base material layer on which a decorative layer is partially provided on one surface.

[5] The double-sided adhesive sheet according to any one of [1] to [4], wherein the second adhesive layer is bonded to the display device.

[6] A laminated body comprising the double-sided adhesive sheet according to any one of [1] to [5], a decorative base material layer laminated on the first adhesive layer, and a second adhesive A display device laminated on top of each other; wherein the decorative substrate layer is provided with a decorative layer on a part of a surface, One surface of the decorative layer is attached to the first adhesive layer.

[7] The laminated body according to [6], further comprising a third adhesive layer and a surface covering layer, a third adhesive layer on the decorative base material layer, and a third adhesive layer There is a surface covering layer.

[8] A method for manufacturing a laminated body, including: The first adhesive layer of the double-sided adhesive sheet according to any one of [1] to [5] is brought into contact with a surface of a decorative base material layer having a decorative layer on a part of the surface adjacent to the decorative layer side, A step of irradiating active energy rays from the second adhesive layer side in this state to completely harden the first adhesive layer; and A step of attaching a display device to the second adhesive layer.

According to the present invention, a double-sided adhesive sheet having both the properties of step tracking and outgassing resistance can be obtained. The double-sided adhesive sheet of the present invention can also be effectively used for bonding of adherends that will not be penetrated by ultraviolet rays.

10‧‧‧ substrate layer

12‧‧‧ the first adhesive layer

14‧‧‧Second adhesive layer

20‧‧‧Decorative substrate layer

25‧‧‧Decorative layer

30‧‧‧ Adhesive

40‧‧‧3rd adhesive layer

50‧‧‧ surface cover

100‧‧‧ double-sided adhesive sheet

200‧‧‧Laminated body

FIG. 1 is a schematic cross-sectional view illustrating an aspect of the double-sided adhesive sheet of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating the construction of a laminated body formed by bonding adherends using the double-sided adhesive sheet of the present invention.

FIG. 3 is a schematic cross-sectional view illustrating the structure of a laminated body formed by bonding adherends using the double-sided adhesive sheet of the present invention.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below is based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

(Double-sided adhesive sheet)

The invention relates to a base material layer provided with a light transmittance of 50% or more at a wavelength of 370 nm, a first adhesive layer provided on one side of the base material layer and hardenable after bonding, and provided on the base material layer. A double-sided adhesive sheet with a second adhesive layer on one surface side and a thickness of 5 μm or more and 75 μm or less.

Since the double-sided adhesive sheet of the present invention has the above-mentioned structure, it has properties of both step tracking and outgassing resistance. In the double-sided adhesive sheet of the present invention, the first adhesive layer is an adhesive layer that can be hardened after being adhered to an adherend, and is in a soft semi-hardened state before being adhered. In this state, since the first adhesive layer side is bonded to the adherend side having the uneven structure, the step of the uneven portion can be easily tracked. Then, after the active energy ray is irradiated from the second adhesive layer side, post-curing (formal hardening) is performed to make the first adhesive layer completely hardened, and it can be firmly adhered to the adherend, and can Shows excellent outgassing resistance. Furthermore, in the present invention, the first adhesive layer and the second adhesive layer are laminated with the base layer interposed therebetween. With this configuration, even if the first adhesive layer is completely hardened, the soft second The adhesive layer exhibits good wettability (adhesion) to the adherend.

In addition, the "semi-hardened state" in this specification refers to a state in which a part of the hardened part is cured by heat or active energy rays before the adhesive layer is attached to the adherend, and is soft before post-hardened (formally hardened). status. The "semi-hardened state" refers to a state where the dynamic viscoelasticity is 1.5 times or more after post-hardening (formal hardening). The dynamic viscoelasticity is preferably 1.5 times to 1000 times, more preferably 2 times to 100 times. In the semi-hardened state of the present invention, the dynamic viscoelasticity of the adhesive layer is preferably 1.0 × 10 ⁶ Pa or less, more preferably 8.0 × 10 ⁵ Pa or less, and particularly preferably 5.0 × 10 ⁵ Pa or less. The "fully hardened (formally hardened) state" refers to a state in which the adhesive layer is irradiated with active energy rays to harden the adhesive layer further.

FIG. 1 is a schematic cross-sectional view illustrating an aspect of the double-sided adhesive sheet of the present invention. As shown in FIG. 1, the double-sided adhesive sheet 100 is provided with a base material layer 10. Then, the double-sided adhesive sheet 100 is provided with a first adhesive layer 12 on one side of the base material layer 10 and a second adhesive layer 14 on the other side of the base material layer 10. The first adhesive layer 12 has a property of being hardened after being adhered to an adherend, and the thickness of the second adhesive layer 14 is 5 μm or more and 75 μm or less.

The thickness of the entire double-sided adhesive sheet of the present invention is preferably 50 μm or more, more preferably 100 μm or more, and particularly preferably 150 μm or more. The thickness of the entire double-sided adhesive sheet is preferably 1 mm or less, and more preferably 0.5 mm or less.

The double-sided adhesive sheet of the present invention is preferably used for laminating adherends with steps. In this case, the first adhesive layer is adhered to the side of the adherend having a step. The adherend system having a step may be, for example, a decorative base material layer having a decorative layer on a part of the surface, and the first adhesive layer is bonded to the side of the decorative base material layer provided with the decorative layer. on. Since the first adhesive layer has excellent step-trackability, the double-sided adhesive sheet of the present invention is preferably used for such an adherend having a step.

The decorative base material layer having a decorative layer may be a resin base material layer. Because the present invention is double-sided The pressure-sensitive adhesive sheet is excellent in outgassing resistance, so even if the base material layer is a resin layer, the occurrence of bubbles after bonding can be suppressed.

In the double-sided adhesive sheet of the present invention, the second adhesive layer is preferably adhered to the optical member. The optical component may be, for example, a display device, and the display device is preferably, for example, a liquid crystal display device (liquid crystal display panel), a plasma display device (plasma display panel), an organic electroluminescent display device (organic EL panel), or the like.

(Base material layer)

The double-sided adhesive sheet of the present invention contains a base material layer. The base material layer is provided between the first adhesive layer and the second adhesive layer, and has a function of preventing monomer components and the like of the adhesive from moving from the first adhesive layer to the second adhesive layer. By setting the substrate layer in this way, it is possible to improve the step tracking property and the outgas resistance of the double-sided adhesive sheet.

The base material layer contains a resin. Examples of the resin contained in the base material layer include polyolefin resins such as polyethylene resin and polypropylene resin; polyethylene terephthalate resin, polyethylene naphthalate resin, and polybutylene terephthalate. Polyester resins such as ester resins; various synthetic resins such as polyvinyl chloride resins, polystyrene resins, polyurethane resins, polycarbonate resins, polyamide resins, polyimide resins, fluorine resins, and cycloolefin polymer resins. Among them, it is preferable to use at least one selected from polyethylene terephthalate resin (PET resin) and cycloolefin polymer resin (COP resin), and it is more preferable to use polyethylene terephthalate resin. (PET resin).

The light transmittance of the substrate layer at a wavelength of 370 nm may be 50% or more, preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more. By changing the wavelength of the substrate layer to 370nm The light transmittance is set within the above range. Post-curing of the first adhesive layer can be performed by irradiating active energy rays from the second adhesive layer side, and ultraviolet rays cannot be laminated on the first adhesive layer side. Sticky.

The light transmittance at a wavelength of 370 nm of the base material layer is a value measured using an ultraviolet-visible spectrometer (type: Solid-Spec 3700, manufactured by Shimadzu Corporation).

The thickness of the substrate layer is preferably 20 μm or more, more preferably 40 μm or more, and particularly preferably 50 μm or more. The thickness of the substrate layer is preferably 500 μm or less, more preferably 400 μm or less, and particularly preferably 300 μm or less.

(1st adhesive layer)

The first adhesive layer is an adhesive layer provided on one side of the base material layer. The first adhesive layer has a property of being hardened after being adhered to an adherend. That is, the first adhesive layer is preferably an adhesive layer having an active energy ray-curing ability.

The first adhesive layer is preferably an adhesive layer having an active energy ray-hardening ability. In this specification, an adhesive layer having an active energy ray-curing ability may also be referred to as a "dual-curing adhesive layer". Here, the adhesive layer having an active energy ray-curing ability is an adhesive layer that is cured in multiple stages, for example, an adhesive layer formed of an adhesive composition having both thermosetting properties and active energy ray-curing properties. In the present invention, it is preferable that the first adhesive layer is thermally cured at the first stage, and can be cured at the second stage using active energy. In the double-sided adhesive sheet of the present invention, the first adhesive layer is preferably laminated according to a semi-hardened state subjected to thermal hardening, and preferably the first adhesive layer is used after being adhered to the adherend to use active energy. To harden. That is, in the double-sided adhesive sheet of the present invention, the first adhesive layer preferably has an active energy ray hardening ability. In addition, the hardening step after the first adhesive layer is adhered to the adherend may be a multi-stage hardening step.

The thickness of the first adhesive layer is preferably 50 μm or more, more preferably 75 μm or more, and particularly preferably 90 μm or more. The thickness of the first adhesive layer is preferably 250 μm or less, more preferably 200 μm or less, and particularly preferably 150 μm or less. By setting the thickness of the first adhesive layer within the above range, it is possible to more effectively improve the step traceability. In addition, the outgas resistance of the double-sided adhesive sheet can be improved.

The first adhesive layer may be an adhesive layer having a post-curing ability. Such an adhesive layer system can be formed, for example, from (a) a double hardening-type adhesive composition, or (b) an adhesive composition containing a dehydrogenating crosslinking agent. In the present invention, in addition to the double-hardening type adhesive composition, even when an adhesive composition containing a dehydrogenating type crosslinking agent is used, an adhesive layer having a post-hardening ability can be obtained. In this case, the post-hardening step can also be performed by irradiation with active energy rays.

((a) Double hardening type adhesive composition)

The first adhesive layer is preferably formed of a double-hardening adhesive composition. The double-hardening adhesive composition preferably contains a matrix polymer (A) containing a non-crosslinkable (meth) acrylate unit (a1) and an acrylic monomer unit (a2) having a crosslinkable functional group. , Monomer (B), cross-linking agent (C) that reacts with matrix polymer (A) by heat, polymerization initiator that starts polymerization reaction of monomer (B) by irradiation with active energy rays (D), and solvent (E).

In addition, in this specification, "(meth) acrylate" means covering both "acrylate" and "methacrylate", and "(meth) acrylic" means covering "acrylic" And "methacrylic acid".

<Matrix polymer (A)>

The matrix polymer (A) contains a non-crosslinkable (meth) acrylate unit (a1) and an acrylic monomer unit (a2) having a crosslinkable functional group. The matrix polymer preferably has transparency to such an extent that the visibility of the display device is not reduced. In addition, in this specification, a "unit" is a repeating unit (monomer unit) which comprises a polymer.

The non-crosslinkable (meth) acrylate unit (a1) is a repeating unit derived from an alkyl (meth) acrylate. Examples of the alkyl (meth) acrylate system include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) N-butyl acrylate, isobutyl (meth) acrylate, third butyl (meth) acrylate, n-amyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethyl (meth) acrylate Hexyl ester, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, ( Isodecyl (meth) acrylate, n-undecyl (meth) acrylate, n-decyl (meth) acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, ( Ethoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, and the like. These systems can be used alone or in combination of two or more.

Among the above-mentioned (meth) acrylic acid alkyl esters, from the viewpoint of improving adhesion, it is preferably selected from methyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethyl (meth) acrylate. At least one kind of hexyl ester is selected.

The acrylic monomer unit (a2) having a crosslinkable functional group is particularly preferably a hydroxyl-containing monomer unit, an amine-containing monomer unit, an epoxypropyl group-containing monomer unit, and a carboxyl-containing monomer unit. Wait. These monomer units may be one type or two or more types.

The hydroxyl-containing monomer unit is a repeating unit derived from a hydroxyl-containing monomer. Examples of the hydroxyl-containing single system include: (methyl) -2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, etc. Hydroxyalkyl acrylate; (meth) acrylic acid mono (diethylene glycol), etc. (meth) acrylic acid [(mono, di, or poly) alkylene glycol]; monocaprolactone (meth) acrylate And other (meth) acrylates.

Examples of the amine group-containing monomer unit include repeating units derived from an amine group-containing monomer such as (meth) acrylamidoamine and allylamine.

The glycidyl group-containing monomer unit may be a repeating unit derived from a glycidyl group-containing monomer such as glycidyl (meth) acrylate.

Examples of the carboxyl group-containing monomer unit include acrylic acid and methacrylic acid.

The content of the crosslinkable acrylic monomer unit (a2) in the matrix polymer (A) is preferably 0.01% by mass or more and 40% by mass or less. When the content of the crosslinkable acrylic monomer unit (a2) is at least the lower limit of the above range, it has sufficient crosslinkability to maintain the semi-hardened state, and if it is below the upper limit of the above range, then It can maintain necessary adhesive properties.

The matrix polymer (A) may contain other monomer units other than the non-crosslinkable (meth) acrylate unit (a1) and the acrylic monomer unit (a2) having a crosslinkable functional group, if necessary. Other single systems can be copolymerized with non-crosslinkable (meth) acrylates and acrylic monomers with crosslinkable functional groups. Examples include (meth) acrylonitrile, vinyl acetate, and benzene. Ethylene, vinyl chloride, vinyl pyrrolidone, vinyl pyridine and the like. The content of an arbitrary monomer unit of the matrix polymer (A) is preferably 20% by mass or less.

The weight average molecular weight of the matrix polymer (A) is preferably from 100,000 to 2 million. By setting the weight average molecular weight within the above range, the semi-hardened state of the first adhesive layer can be maintained, and sufficient step traceability can be ensured. The weight average molecular weight of the matrix polymer (A) is a value before cross-linking using a cross-linking agent. The weight-average molecular weight is a value determined by a size exclusion chromatography (SEC) method and determined based on a polystyrene standard. The matrix polymer (A) may be a commercially available product or may be synthesized by a known method.

The weight average molecular weight of the matrix polymer (A) can also be measured by a gel permeation chromatography (GPC). In this case, the measurement conditions of the gel permeation chromatography (GPC) are as follows.

Solvent: Tetrahydrofuran (THF)

Columns: Shodex KF801, KF803L, KF800L, KF800D (used by Showa Denko Co., Ltd. for 4 branches)

Column temperature: 40 ℃

Sample concentration: 0.5% by mass

Detector: RI-2031plus (manufactured by JASCO)

Pump: RI-2080plus (manufactured by JASCO)

Flow (flow rate): 0.8ml / min

Injection volume: 10 μl

Calibration curve: A calibration curve was prepared using 10 samples of standard polystyrene Shodex standard polystyrene (manufactured by Showa Denko Corporation) Mw = 1320-2,500,000.

<Monomer (B)>

The monomer (B) is preferably a monofunctional monomer having at least one polymerizable unsaturated group. (B1) or at least one of the polyfunctional monomer (B2) having at least two polymerizable unsaturated groups. The monomer (B) preferably contains one of a monofunctional monomer (B1) or a polyfunctional monomer (B2), and may also be a monofunctional monomer (B1) and a polyfunctional monomer (B2). ) Both sides contain.

By containing the monomer (B), when the adhesive composition is thermally hardened, the adhesive layer of the thermally hardened material is in a semi-hardened state and can have an active energy ray hardening ability.

The polymerizable unsaturated group is preferably a group containing an ethylenic double bond, and examples thereof include a (meth) acrylfluorenyl group and a vinyl group. Among these, (meth) acrylfluorenyl is more preferable.

酯、(甲基)丙烯酸-2-乙基己酯等之中選擇至少1種。 The monofunctional monomer (B1) is preferably selected from amyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, n-octyl (meth) acrylate, and (meth) acrylic acid Isooctyl, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate Esters, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, isopropyl (meth) acrylate

At least one kind is selected from esters, 2-ethylhexyl (meth) acrylate, and the like.

酯、(甲基)丙烯酸-2-乙基己酯之中選擇至少1種。 Among these, more preferred are pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, n-octyl (meth) acrylate, and (meth) ) Isooctyl acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate Alkyl ester, lauryl (meth) acrylate, isostearyl (meth) acrylate, isomethacrylate (meth) acrylate

At least one selected from the group consisting of an ester and 2-ethylhexyl (meth) acrylate.

Examples of the polyfunctional monomer (B2) include ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and 1,3-butanediol di (meth) acrylate. Di (meth) acrylic acid Butanediol ester, 1,9-nonanediol di (meth) acrylate, 1,6-hexanediol diacrylate, polybutylene glycol di (meth) acrylate, bis (meth) acrylate Neopentyl glycol acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate (Meth) acrylates of polyhydric alcohols such as esters, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate; vinyl methacrylate and the like.

The monomer (B) preferably has no functional group that is reactive with the functional group of the acrylic monomer unit (a2). For example, the monomer (B) preferably has the same functional group (for example, a hydroxyl group) as the acrylic monomer unit (a2), or does not have a functional group.

The monomer (B) is any one of the monofunctional monomer (B1) or the polyfunctional monomer (B2) alone, or two or more kinds of the monofunctional monomer (B1) and / or may be used in combination. Polyfunctional monomer (B2).

In the adhesive composition, the content of the monomer (B) is appropriately selected according to the composition, molecular weight, and crosslinking density of the matrix polymer (A), and is not particularly limited. Compared with the matrix polymer (A), 100 parts by mass, preferably 5 parts by mass or more and 150 parts by mass or less. By setting the content of the monomer (B) within the above range, it is possible to improve the performance of preventing the step tracking from being deformed or distorted, and the processability can be improved.

<Crosslinking agent (C)>

唑啉化合物、氮丙啶化合物、金屬螯合化合物、丁基化三聚氰胺化合物等公知交聯劑中選擇。該等之中，就從具有交聯性官能基的丙烯酸 單體單元(a2)可輕易交聯觀點，較佳係異氰酸酯化合物、環氧化合物。例如交聯性官能基係含有羥基的情況，就從羥基反應性的觀點，更佳係使用異氰酸酯化合物。 The cross-linking agent (C) can be appropriately selected in consideration of the reactivity with the cross-linkable functional group of the matrix polymer (A). For example, isocyanate compounds, epoxy compounds,

The oxazoline compound, the aziridine compound, the metal chelate compound, and the butylated melamine compound are selected from known crosslinking agents. Among these, from the viewpoint that the acrylic monomer unit (a2) having a crosslinkable functional group can be easily crosslinked, it is preferably an isocyanate compound or an epoxy compound. For example, when the crosslinkable functional group contains a hydroxyl group, an isocyanate compound is more preferably used from the viewpoint of hydroxyl reactivity.

Examples of the isocyanate compound include toluene diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the like.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol diglycidyl ether, neopentyl Glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, tetraglycidyl xylene diamine, 1,3-bis (N, N-diglycidylaminomethyl) ring Hexane, trimethylolpropane polyglycidyl ether, diglycerin polyglycidyl ether, polyglycerin polyglycidyl ether, sorbitol polyglycidyl ether and the like.

The content of the cross-linking agent (C) in the adhesive composition is appropriately selected according to the required physical properties of the adhesive, etc. It is preferably 0.01 parts by mass or more and 5 parts by mass or less based on 100 parts by mass of the matrix polymer (A). .

<Polymerization initiator (D)>

The polymerization initiator (D) is only required to start the polymerization reaction of the monomer (B) by irradiation with active energy rays, and known materials such as a photopolymerization initiator can be used.

Here, the "active energy ray" refers to a person having an energy quantum in an electromagnetic wave or a charged particle beam, and examples thereof include ultraviolet rays, electron beams, visible rays, X-rays, and ion beams. Among these, from the viewpoint of versatility, ultraviolet rays or electron beams are preferred, and ultraviolet rays are more preferred.

系起始劑、胺系起始劑等。 Examples of the polymerization initiator (D) include acetophenone-based initiators, benzoin ether-based initiators, diphenylketone-based initiators, hydroxyalkyl phenone-based initiators, and oxygen and sulfur.

Based initiators, amine based initiators, and the like.

Specific examples of the acetophenone-based initiator include diethoxyacetophenone, benzyldimethylketal, and the like.

Specific examples of the benzoin ether initiator are benzoin, benzoin methyl ether, and the like.

Specific examples of the diphenyl ketone-based initiator include diphenyl ketone, methyl benzophenylate and the like.

Specific examples of the hydroxyalkyl phenone-based initiator include 1-hydroxy-cyclohexyl-phenyl-one and the like.

系起始劑具體係可舉例如：2-異丙基氧硫

、2,4-二甲基氧硫

等。 Oxygen sulfur

Specific examples of the initiator are: 2-isopropyloxysulfur

2,4-dimethyloxysulfur

Wait.

Specific examples of the amine-based initiator include triethanolamine and ethyl 4-dimethylbenzoate.

The content of the polymerization initiator (D) in the adhesive composition, the content of the monomer (B), and the amount of active energy ray exposure during complete curing are appropriately selected. Specifically, it is preferably 0.05% by mass or more and 10% by mass or less with respect to the total mass of the monomer (B).

<Solvent (E)>

烷、四氫呋喃等醚類；丙酮、甲乙酮、甲基異丁酮、異佛爾酮、環己酮等酮類；醋酸甲酯、醋酸乙酯、醋酸丁酯、醋酸異丁酯、醋酸戊酯、酪酸乙酯等酯類；乙二醇單甲醚、乙 二醇單乙醚、乙二醇單甲醚醋酸酯、丙二醇單甲醚、丙二醇單乙醚、丙二醇單甲醚醋酸酯等多元醇及其衍生物。 The solvent (E) is used for improving the coating suitability of the adhesive composition. Examples of the solvent (E) include hydrocarbons such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; methylene chloride, trichloroethane, and trichloromethane. Halogenated hydrocarbons such as ethylene, tetrachloroethylene, and dichloropropane; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and diacetone alcohol; diethyl ether, diisopropyl ether, and

Ethers such as alkane, tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone; methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, Polyesters such as ethyl butyrate; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, and their derivatives Thing.

The solvent (E) is preferably a solvent which does not have a polymerizable unsaturated group and has a higher vapor pressure at 25 ° C than the monofunctional monomer (b1). Examples of solvents that do not have a polymerizable unsaturated group and have a higher vapor pressure at 25 ° C than the monofunctional monomer (b1) include hexane, heptane, cyclohexane, benzene, toluene, ethanol, and isopropyl. Alcohols, diisopropyl ether, tetrahydrofuran, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and the like.

<Optional component>

The adhesive composition system may further contain a plasticizer. The plasticizer is preferably a non-functional acrylic polymer. The non-functional acrylic polymerization system is as follows: a polymer composed only of acrylic monomer units having no functional group other than the acrylate group; or an acrylic monomer unit having no functional group other than the acrylate group; A polymer composed of non-acrylic monomeric units based on radicals. Since the non-functional acrylic polymer does not crosslink with the matrix polymer (A), it is possible to improve the step traceability without affecting the properties of the adhesive.

The adhesive composition is within a range that does not impair the effect of the present invention, and may contain other components than the above. The other components are, for example, well-known components as additives for adhesives. For example: light stabilizers such as antioxidants, anti-corrosives, adhesion promoters, silane coupling agents, hindered amine compounds, etc.

((b) Adhesive composition containing dehydrogenated crosslinking agent)

The dehydrogenated crosslinking agent-containing adhesive composition is an adhesive composition containing an acrylic polymer as a main component. Here, the "main component" means a component containing 50% by mass or more with respect to the total mass of the adhesive composition.

The acrylic polymer is preferably a copolymer containing a non-crosslinkable (meth) acrylate unit (a1) as a main component and containing an acrylic monomer unit (a2) having a crosslinkable functional group therein. In this specification, "unit" is a repeating unit (monomer unit) which comprises a polymer.

Examples of the non-crosslinkable (meth) acrylate unit (a1) constituting the acrylic polymer include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. , Butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, (formyl) (Meth) acrylate (meth) acrylic acid alkyl monomers such as isononyl acrylate, lauryl (meth) acrylate, and isostearyl (meth) acrylate. These can be used in combination of two or more kinds as needed.

啉基丙烯醯胺、丙烯酸-N,N-二甲胺基乙酯、丙烯酸-N-第三丁胺基乙酯等含胺基之(甲基)丙烯酸酯；(甲基)丙烯酸環氧丙酯等環氧基等。該等視需要亦可併用2種以上。 Examples of the acrylic monomer unit (a2) having a crosslinkable functional group include (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, and fumaric acid. Dicarboxylic anhydride-containing monomers such as carboxylic acid; 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, polyethylene glycol ( (Meth) acrylate-containing monomers such as hydroxyl groups; (meth) acrylamido,

(Meth) acrylic acid-containing (meth) acrylates, such as phosphonium allylamine, acrylic acid, N-N, dimethylamino ethyl ester, acrylic acid, N-tertiary butyl amino ethyl ester; glycidyl (meth) acrylate Ester, etc. These can be used in combination of two or more kinds as needed.

The acrylic polymer may contain a non-crosslinkable (meth) acrylate unit as needed (a1) and other monomer units other than the acrylic monomer unit (a2) having a crosslinkable functional group. The other single systems may be copolymerized with a non-crosslinkable (meth) acrylate and an acrylic monomer having a crosslinkable functional group. Other single systems include, for example, (meth) acrylonitrile, vinyl acetate, styrene, vinyl chloride, vinylpyrrolidone, vinylpyridine, and the like.

The weight average molecular weight of the acrylic polymer is preferably 100,000 or more and 2 million or less, and more preferably 300,000 or more and 1.5 million or less. By setting the weight average molecular weight within the above range, sufficient durability and flexibility can be secured. The weight average molecular weight of the acrylic polymer is a value before crosslinking with a crosslinking agent. The weight-average molecular weight is a value determined by a size exclusion chromatography (SEC) method and determined based on a polystyrene standard. The weight-average molecular weight of the acrylic polymer can also be measured by a gel permeation chromatography (GPC).

When polymerizing an acrylic polymer, for example, a solution polymerization method can be applied. Examples of the solution polymerization method include an ion polymerization method and a radical polymerization method. Examples of the solvent used at this time include tetrahydrofuran, chloroform, ethyl acetate, toluene, hexane, acetone, and methyl ethyl ketone.

、2-氯氧硫

、2-甲基氧硫

、2,4-二甲基氧硫

、異丙基氧硫

、莰醌、二苯并環庚酮、2-乙基蒽醌、3,3',4,4'-四(過氧化第三丁基羰基)二苯基酮、苄基、9,10-菲醌等。其中，較佳係二苯基酮、甲基二苯基 酮、2,4,6-三甲基二苯基酮。 The dehydrogenated crosslinking agent-containing adhesive composition system contains a dehydrogenated photopolymerization initiator. Examples of the dehydrogenation type photopolymerization initiator system include diphenyl ketone, benzamidobenzoic acid, methyl benzamidobenzoate, 4-phenyldiphenyl ketone, hydroxydiphenyl ketone, 3 , 3'-dimethyl-4-methoxydiphenyl ketone, 2,4,6-trimethyldiphenyl ketone, 4-methyldiphenyl ketone, oxysulfur

2-chlorooxysulfur

2-methyloxysulfur

2,4-dimethyloxysulfur

Isopropyloxysulfur

, Fluorenone, dibenzocycloheptanone, 2-ethylanthraquinone, 3,3 ', 4,4'-tetrakis (third butylperoxy) diphenyl ketone, benzyl, 9,10- Phenanthrenequinone and so on. Among these, diphenyl ketone, methyl diphenyl ketone, and 2,4,6-trimethyl diphenyl ketone are preferred.

唑啉化合物、氮丙啶化合物、金屬螯合化合物、丁基化三聚氰胺化合物等。 The adhesive composition containing a dehydrogenated crosslinking agent may contain a crosslinking agent in addition to the dehydrogenated photopolymerization initiator. Examples of other crosslinking agents include: isocyanate compounds, epoxy compounds,

An oxazoline compound, an aziridine compound, a metal chelate compound, a butylated melamine compound, and the like.

The content of the dehydrogenation type photopolymerization initiator in the adhesive composition containing the dehydrogenation type crosslinking agent is appropriately selected according to the desired physical properties of the adhesive, and is not particularly limited. For example, it is relative to the acrylic polymer. 100 parts by mass, preferably 0.01 parts by mass or more and 20 parts by mass or less.

The dehydrogenated crosslinking agent-containing adhesive composition may contain a solvent. Examples of the solvent system are: methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, toluene, n-hexane, n-butanol, methyl isobutyl ketone, methyl methyl ketone, ethyl methyl ketone, cyclohexanone, ethyl acetate , Butyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, N-methyl-2-pyrrolidone, and the like. These systems can be used alone or in combination of two or more.

The dehydrogenated crosslinking agent-containing adhesive composition may contain other components in addition to the above as long as the effect of the present invention is not impaired. The other components are, for example, well-known components as additives for adhesives. For example: light stabilizers such as antioxidants, anti-corrosives, adhesion promoters, silane coupling agents, hindered amine compounds, etc.

(Second adhesive layer)

The second adhesive layer is an adhesive layer provided on the other side of the base material layer. The thickness of the second adhesive layer is 5 μm or more and 75 μm or less.

The thickness of the second adhesive layer may be 5 μm or more, and is preferably 10 μm or more. The thickness of the second adhesive layer may be 75 μm or less, preferably 60 μm or less, and more preferably 50 μm or less. By setting the thickness of the second adhesive layer within the above range, the outgassing resistance can be effectively improved.

The second adhesive layer is preferably formed of a second adhesive composition containing a matrix polymer as a main component. The matrix polymer preferably contains at least one selected from an acrylic polymer, a rubber polymer, a silicon polymer, an amine ester polymer, and a polyester polymer. Among them, the matrix polymer preferably contains at least one selected from an acrylic polymer, a rubber-based polymer, and a silicon-based polymer, and more preferably contains at least one selected from an acrylic polymer and a rubber-based polymer. Of these, particularly preferred are acrylic polymers.

The other components contained in the second adhesive composition are the same as the other components contained in the first adhesive composition.

The thickness of the second adhesive layer is preferably thinner than the thickness of the first adhesive layer. When the thickness of the first adhesive layer is set to A and the thickness of the second adhesive layer is set to B, it is preferably A> B, more preferably A> 1.5B, and particularly good A> 2B. By setting the relationship between the thicknesses of the first adhesive layer and the second adhesive layer as described above, outgassing resistance and step tracking can be more effectively improved.

(Double-sided adhesive sheet with release sheet)

The present invention may also be directed to a double-sided adhesive sheet having a release sheet laminated on at least one side of the double-sided adhesive sheet. The release sheet is laminated on at least one side of the double-sided adhesive sheet, preferably both sides of the double-sided adhesive sheet are laminated.

The release sheet is a sheet having release properties on at least one side. The release sheet may be, for example, a release sheet substrate, a release laminated sheet having a release agent layer provided on one surface of the release sheet substrate, or a polyethylene film or polypropylene film which is a low-polarity substrate. Polyolefin film.

The base material for a release sheet of a release laminated sheet uses paper or a polymer film. As the release agent system constituting the release agent layer, for example, a general-purpose addition-type or condensation-type silicon-based release agent or a compound having a long-chain alkyl group can be used. Particularly preferred is the use of a highly reactive addition-type silicon-based release agent.

Specific examples of the silicon-based release agent include: BY24-4527 and SD-7220 manufactured by Toray ‧ Dow Corning Silicones; KS-3600, KS-774, and X62-2600 manufactured by Shin-Etsu Chemical Industry Co., Ltd. and the like. In addition, it is preferable that the organic silicon compound having a SiO ₂ unit and a (CH ₃ ) ₃ SiO _1/2 unit or a CH ₂ = CH (CH ₃ ) SiO _1/2 unit in a polysiloxane-based release agent may be contained. Silicone. Specific examples of the silicone resin include, for example, BY24-843, SD-7292, and SHR-1404 manufactured by Toray‧Dow Corning Silicones; KS-3800 and X92-183 manufactured by Shin-Etsu Chemical Industry Co., Ltd., and the like.

In order to facilitate the release of the release sheet, it is preferable that one of the release sheet and the other release sheet have different release properties. That is, if the releasability from one of them is different from the releasability from the other, it is possible to easily peel only the release sheet having a higher releasability first. In this case, it is only necessary to adjust the releasability of one release sheet and the other release sheet in accordance with the bonding method and bonding sequence.

When an adhesive composition is apply | coated to a peeling sheet, it can implement using a well-known coating apparatus. The coating device may be, for example, a blade coater, an air knife coater, a roll coater, a rod coater, a gravure coater, a microgravure coater, a rod blade coater, or a lip type. Coating machine, die coating machine, shower coating machine, etc. The heating system of a coating film can be implemented using well-known heating apparatuses, such as a heating furnace and an infrared lamp.

(Manufacturing method of double-sided adhesive sheet)

The manufacturing method of the double-sided adhesive sheet of the present invention includes: a step of obtaining a first adhesive layer that can be hardened after bonding; a step of obtaining a second adhesive layer having a thickness of 5 μm or more and 75 μm or less; A step of laminating a first adhesive layer on one side of a base material layer having a light transmittance of 50% or more; and a step of laminating a second adhesive layer on the other side of the base material layer.

The step of obtaining the first adhesive layer is preferably a step of applying the first adhesive composition on the first release sheet. The application of the first adhesive composition can be performed using a known application device. The coating device can be, for example, a blade coater, an air knife coater, a roll coater, a rod coater, a gravure coater, a microgravure coater, a rod leaf coater, a lip coater, or a mold. Coating machine, shower curtain coating machine, etc. After coating, it is preferable to design a heating and drying step, and the heating and drying step preferably uses a known heating device such as a heating furnace and an infrared lamp.

The step of forming the first adhesive layer is preferably to form the first adhesive having a thickness of 50 μm or more and 250 μm or less. In this case, the coating amount of the first adhesive composition can be determined appropriately in accordance with the solid content concentration and viscosity of the adhesive composition.

The step of obtaining the second adhesive layer is preferably a step of applying a second adhesive composition on the second release sheet. The coating method of the second adhesive composition is, for example, the same as the coating method described above.

The step of forming the second adhesive layer is preferably to form a second adhesive having a thickness of 5 μm or more and 75 μm or less.

In the step of bonding the first adhesive layer on one side of the base material layer having a light transmittance of 50% or more at a wavelength of 370 nm, and the step of bonding the second adhesive layer on the other side of the base material layer, The first adhesive layer and the second adhesive layer are bonded to each surface of the material layer.

(How to use double-sided adhesive sheet)

The method for using the double-sided adhesive sheet of the present invention is preferably when the first adhesive layer of the double-sided adhesive sheet is in a semi-hardened state, and then is adhered to the adherend, and then the active energy ray is irradiated to complete the first adhesive layer. Hardening method. The adherend may also have a step, and such an adherend may be, for example, a decorative substrate layer provided with a decorative layer.

When a double-sided adhesive sheet is bonded to a decorative substrate layer provided with a decorative layer, the active energy ray is irradiated from the side of the second adhesive layer. Before the active energy ray is radiated, the first adhesive layer is in a semi-hardened state, so the step difference between the decorative layer and the decorative substrate layer can be tracked. After the double-sided adhesive sheet is pasted and the step is tracked, the first adhesive layer is completely hardened by active energy rays, so that the cohesive force of the first adhesive layer is improved, and the adhesion to the decorative substrate layer is improved.

The active energy ray system may be, for example, ultraviolet rays, electron beams, visible rays, X-rays, ion beams, etc., and may be appropriately selected according to the polymerization initiator contained in the adhesive layer. Among these, from the viewpoint of versatility, ultraviolet rays or electron beams are preferred, and ultraviolet rays are more preferred.

The ultraviolet light source can be, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a carbon arc, a xenon arc, or an electrodeless ultraviolet lamp.

For the electron beam system, for example, a Cockroft-Walton type, a Van-de-Graaff type, a resonant transformer type, an insulated core transformer type, a linear type, and a Dynamitron can be used. Electron beams emitted from various electron beam accelerators such as high-frequency and high-frequency types.

It is preferable that the second adhesive layer is adhered to the adherend after the first adhesive layer is completely hardened. The second adhesive layer does not have to be an adhesive layer having a post-hardening ability, and can be adhered to an adherend even without irradiating active energy rays. That is, the second adhesive layer is an active energy ray non-curable adhesive layer.

The adherend adhered to the second adhesive layer is preferably an optical member such as a display device. The display device may be, for example, a liquid crystal display device (liquid crystal display panel), a plasma display device (plasma display panel), an organic electroluminescent display device (organic EL panel), and the like.

(Laminated body) <First aspect>

The present invention also relates to a laminated body in which other layers are further laminated on the double-sided adhesive sheet. The first aspect of such a laminate may include, for example, the above-mentioned double-sided adhesive sheet, a decorative substrate layer laminated on the first adhesive layer, and a display device laminated on the second adhesive layer; body. Wherein, the decorative base material layer is provided with a part of a surface The decorative layer, and the surface provided with the decorative layer is adhered to the first adhesive layer.

FIG. 2 is a schematic cross-sectional view illustrating a configuration in which a laminated body 200 is formed by laminating an adherend using the double-sided adhesive sheet of the present invention. As shown in FIG. 2, a decorative base material layer 20 provided with a decorative layer 25 is laminated on the first adhesive layer 12, and an adherend 30 is laminated on the second adhesive layer 14. Here, the adherend 30 is preferably a display device. The display device may be, for example, a liquid crystal display device (liquid crystal display panel), a plasma display device (plasma display panel), an organic electroluminescence display device (organic EL panel), or the like.

<Decorative base material layer>

The decorative base material layer of the present invention may have a property that ultraviolet rays do not penetrate. In the present invention, when the first adhesive layer is hardened, an active energy ray can be irradiated from the second adhesive layer side. Therefore, the adherend to which the first adhesive layer is adhered may also be one that does not penetrate ultraviolet rays, and the double-sided adhesive sheet system of the present invention can be used for attaching various adherends.

In the laminated body, the decorative base material layer may have a multilayer structure. When the decorative base material layer has a multilayer structure, the decorative base material layer preferably has, for example, a base resin layer and a functional layer.

The functional layer is, for example, at least one layer selected from a primer layer and a hard coat layer. That is, the decorative base material layer preferably contains a base resin layer and at least one layer selected from a primer layer and a hard coat layer.

<Primer layer>

The primer layer is preferably an undercoat layer of a base resin layer. By designing the primer layer, when using solvent In the case of a formulation type adhesive layer, the influence of the solvent on the base resin layer can be suppressed to a minimum. In addition, when the substrate layer is provided with a multilayer structure of a substrate resin layer and a primer layer, the thickness of the substrate resin layer is greater than the thickness of the primer layer, and the two can be distinguished by setting such a thickness.

The resin system constituting the primer layer may be, for example, an epoxy resin. Either a single-liquid curing type or a two-liquid curing type can be used arbitrarily. A water-soluble epoxy resin is preferably used. Examples of the water-soluble epoxy resin include polyamine epoxy resin. Polyamine epoxy resin is a polyamine obtained by reacting a polyalkylene polyamine such as diethylenetriamine and triethylenetetramine with a dicarboxylic acid such as adipic acid. Polyamines can be obtained by reaction with epichlorohydrin.

When a water-soluble epoxy resin is used as the resin for forming the primer layer, other water-soluble resins such as a polyvinyl alcohol-based resin may be mixed in order to further improve the coatability. In addition to partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, polyvinyl alcohol-based resins can also be, for example, carboxyl-modified polyvinyl alcohol, acetoacetic acid-modified polyvinyl alcohol, and methylol modified Polyvinyl alcohol, amine-modified polyvinyl alcohol and other modified polyvinyl alcohol resins.

The resin constituting the primer layer is preferably used in a state of being dissolved in a solvent. The solvent used in this case is preferably water, but an organic solvent may be used. Organic solvents can also be used: aromatic hydrocarbons such as benzene, toluene, xylene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; esters such as ethyl acetate, isobutyl acetate; dichloromethane, trichloro Chlorinated hydrocarbons such as ethylene and chloroform; alcohols such as ethanol, 1-propanol, 2-propanol, and 1-butanol; and other general organic solvents.

<Hard coating>

The hard coat layer is preferably a layer provided to improve the suitability for decorative printing. Furthermore, the hard coat layer can also improve the strength and durability of the laminate.

The hard coat layer preferably contains a hard component capable of imparting hardness. The hard component system may be, for example, a crosslinked polymer. Examples of the cross-linking polymerization system include a monofunctional monomer polymer and a polyfunctional monomer polymer. The polyfunctional monomer polymer is preferably a polymer of a polymerizable monomer containing a trifunctional or more polyfunctional monomer, and more preferably a polymer of a polymerizable monomer containing a polyfunctional monomer of tetrafunctional or more. . For example, a copolymer of a mixed monomer of a trifunctional or higher polyfunctional monomer and a difunctional monomer is also a preferred example. In addition, the so-called "monomer" also includes oligomers.

There are no particular restrictions on the types of monomers that can be used to obtain a crosslinked polymer, and preferred examples include acrylic monomers. Specific examples include: dipropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol (weight average molecular weight 600) ) Di (meth) acrylate, propylene oxide modified neopentyl glycol di (meth) acrylate, modified bisphenol A di (meth) acrylate, tricyclodecane dimethanol bis (methyl) Bifunctional (meth) acrylates such as acrylate, polyethylene glycol (weight average molecular weight 400) di (meth) acrylate; pentaerythritol tri (meth) acrylate, trimethylolpropane tri (methyl) Trifunctional (meth) acrylates such as acrylate, trimethylolpropane ethoxy tri (meth) acrylate, polyether tri (meth) acrylate, glycerol propoxy tri (meth) acrylate, etc. ; Pentaerythritol tetra (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, bis (trimethylolpropane) tetra (meth) acrylate, propionic acid modified dipentaerythritol penta (meth) acrylic acid Esters, dipentaerythritol monohydroxy penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and other (meth) propylenes with more than four functional groups Acid ester.

The monomer or oligomer of the organic compound having a polymerizable unsaturated group may be thermosetting or active energy ray-curing.

The hard coat layer may contain a soft component. Examples of the soft component include: tricyclodecanehydroxymethyl di (meth) acrylate, ethylene oxide modification of bisphenol F, di (meth) acrylate modification, and ethylene oxide modification of bisphenol A. Di (meth) acrylate, ethylene oxide modified di (meth) acrylate of isotricyanic acid, polypropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, etc. Bifunctional (meth) acrylate; trimethylolpropane tri (meth) acrylate, trimethylpropane propylene oxide modified tri (meth) acrylate, trimethylpropane ethylene oxide Modified trifunctional (meth) acrylate such as tri (meth) acrylate; urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, etc. .

The hard coat layer may contain inorganic particles and / or organic particles. When inorganic particles and / or organic particles are contained, it is preferable from the viewpoint of suppressing curing shrinkage. Examples of the inorganic particle system include inorganic oxide particles such as silicon dioxide particles, titanium dioxide particles, zirconia particles, aluminum oxide particles, tin dioxide particles, antimony pentoxide particles, and antimony trioxide particles. Examples of the organic particles include resin particles such as acrylic resin, polystyrene, polysiloxane, melamine resin, benzoguanamine resin, polytetrafluoroethylene, cellulose acetate, polycarbonate, and polyamide. .

When inorganic particles are used, reactive inorganic oxide particles treated with a coupling agent may also be used. When organic particles are used, reactive organic oxide particles treated with a coupling agent may also be used. By performing the treatment with a coupling agent, the binding force with the acrylic polymer can be improved.

The coupling agent system can be, for example, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxy Propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, and the like. These systems can be used alone or in combination of two or more.

The thickness of the hard coat layer is not particularly limited, and is preferably 0.5 μm or more, more preferably 1.0 μm or more, and particularly preferably 2.0 μm or more. The thickness of the hard coat layer is preferably 100 μm or less, and more preferably 50 μm or less.

<Decorative layer>

A decorative layer is provided on one side of the decorative substrate layer. The decorative layer may be a decorative printed layer provided by printing. Examples of the printing method for forming the decorative printing layer include gravure printing and screen printing. The decorative layer may be a decorative printed layer for hiding the outer-frame-shaped electrode, or may be a printed design pattern.

The coating material for constituting the decorative printing layer is not particularly limited, and a known coating material can be used. Examples of the coating system include ultraviolet curable inks and oxidative polymerization inks.

The thickness of the decorative layer is preferably 5 μm or more, more preferably 7 μm or more, and particularly preferably 10 μm or more. The thickness of the decorative layer is preferably 50 μm or less, more preferably 30 μm or less, and particularly preferably 25 μm or less. In addition, the thickness of the decorative layer may be thicker than 50 μm if necessary. In this case, by appropriately adjusting the thickness of the first adhesive layer, the step difference between the decorative layer and the substrate layer can be tracked.

<Second Aspect>

The second aspect of the laminated body may be, for example, a laminated body having a third adhesive layer and a surface covering layer in addition to the laminated body of the first aspect. The laminated system of the second aspect further includes a third adhesive layer and a surface covering layer, a third adhesive layer on the decorative substrate layer, and a surface covering layer on the third adhesive layer.

3 is a schematic cross-sectional view illustrating the configuration of the second aspect laminated body 200 shown in FIG. 3. As shown in FIG. 3, a third adhesive layer 40 is laminated on the decorative base material layer 20, and a surface covering layer 50 is laminated on the third adhesive layer 40.

The surface covering layer 50 may be, for example, a glass plate or a resin layer. Specific examples of the glass plate include inorganic materials such as soda glass, alkali-free glass, and tempered glass. The surface covering layer is preferably a surface resin layer. In this case, a polyethylene terephthalate resin (PET resin), a polycarbonate resin (PC resin), and a polymethyl methacrylate resin (PMMA resin) are preferably used. ) And other resin layers made of transparent resin. These surface resin layers may have a property that ultraviolet rays do not penetrate.

The third adhesive layer is preferably formed of a third adhesive composition containing a matrix polymer as a main component. The matrix polymer preferably contains at least one selected from an acrylic polymer, a rubber polymer, a silicon polymer, an amine ester polymer, and a polyester polymer. Among them, the matrix polymer more preferably contains at least one kind selected from an acrylic polymer, a rubber-based polymer, and a silicon-based polymer, and particularly preferably has at least one kind selected from an acrylic polymer and a rubber-based polymer. Most preferably, it contains an acrylic polymer.

The thickness of the third adhesive layer may be 5 μm or more, and is preferably 10 μm or more. The thickness of the third adhesive layer is only required to be 75 μm or less, preferably 60 μm or less, and particularly preferably 50 μm or less.

(Manufacturing method of laminated body)

The invention also relates to a method for manufacturing a laminated body. The manufacturing method of the laminated body according to the present invention includes: making the first adhesive layer of the double-sided adhesive sheet contact one side of a decorative layer of a decorative base material layer (a part of which is provided with a decorative layer) And in this state, a step of performing active energy ray irradiation from the second adhesive layer side to completely harden the first adhesive layer; and a step of attaching a display device to the second adhesive layer. In the step in which the first adhesive layer is in contact with one side of the decorative layer of the decorative base material layer (a part of which is provided with a decorative layer), the first adhesive layer is preferably in a semi-hardened state.

Examples of the active energy ray include the above-mentioned energy ray, preferably ultraviolet rays or electron beams, and more preferably ultraviolet rays.

The irradiation output of ultraviolet rays is preferably an integrated luminous flux of 100 mJ / cm ² or more and 10,000 mJ / cm ² or less, more preferably 500 mJ / cm ² or more and 5000 mJ / cm ² or less.

In the method for manufacturing a laminated body, before the active energy ray is radiated, the first adhesive layer of the double-sided adhesive sheet is in a semi-hardened state, so even if the adherend has a stepped portion, the adhesive layer can still track the unevenness. After the adhesive sheet is adhered in this manner to track unevenness, the first adhesive layer is completely hardened by using active energy rays, so that the cohesive force of the first adhesive layer is improved, and the adhesion to the adherend is improved.

In the present invention, when the first adhesive layer is completely cured by active energy rays, the active energy rays are irradiated from the second adhesive layer side. By applying active energy ray irradiation from the side of the second adhesive layer, even when the first adhesive layer is bonded to a decorative substrate layer having a decorative layer, the first adhesive layer can be uniformly and completely hardened. As a result, there is no place where the decorative layer prevents the irradiation of active energy rays.

After the first adhesive layer is completely cured, it is preferable to adhere the adherend to the second adhesive layer. The second adhesive layer is not necessarily an adhesive layer having a post-hardening ability, and can be adhered to an adherend without being irradiated with active energy rays. The adherend to be bonded to the second adhesive layer is preferably an optical member such as a display device.

When the laminated system is provided with a third adhesive layer and a surface covering layer in addition to the laminated body of the first aspect, a third adhesive layer is adhered to the surface covering layer, and the third adhesive layer is further added. A decorative base material layer provided with a decorative layer is bonded to the layer. It is best to perform roll bonding when bonding. The decorative base material layer is bonded to the first adhesive layer side of the double-sided adhesive sheet.

[Example]

The following examples and comparative examples are used to describe the features of the present invention in more detail. The materials, usage amounts, proportions, processing contents, processing order, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

(Example 1)

On one side of the separator A (100RL-07V (10.5) manufactured by Oji F-TEX Co., Ltd.), a first adhesive (New Tac Kasei Co., DC124) was applied by a trickle, and the temperature was maintained at 100 ° C for 2 minutes. The first adhesive layer was dried to form a thickness of 100 μm. Next, a first adhesive layer was laminated on one side of a PET film (LUMIRROR® U483, manufactured by Toray Industries, thickness: 75 μm).

A second adhesive composition (manufactured by New Tac Kasei, SA151) was applied on one side of a separator B (manufactured by Oji F-TEX, 75RL-07V (6.5)) with a dripper at 100 ° C. After drying for 2 minutes, a second adhesive layer having a thickness of 25 μm was formed. Next, the PET film was bonded to the back surface on the side of the first adhesive layer, and the second adhesive layer was bonded. Thus, the double-sided adhesive sheet of Example 1 was obtained. The light transmittance of the substrate film (PET film) at a wavelength of 370 nm is shown in Table 1.

(Example 2)

A double-sided adhesive sheet was produced in the same manner as in Example 1 except that SA151, the second adhesive composition, was changed to NA021 manufactured by New Tac Kasei.

(Comparative example 1)

A double-sided adhesive sheet was obtained in the same manner as in Example 1 except that the PET film of the base film was changed to an SRF film. The light transmittance of the substrate film at a wavelength of 370 nm is shown in Table 1.

(Comparative example 2)

In addition to changing the first adhesive composition to DC126 manufactured by New Tac Kasei, the thickness was changed as shown in Table 1. When the first adhesive layer and the second adhesive layer are bonded together without the base film interposed therebetween, the rest are obtained in the same manner as in Example 1. Face adhesive sheet.

(Comparative example 3)

As the first adhesive composition, a single-layer double-sided adhesive sheet was obtained using DC126 manufactured by New Tac Kasei.

(Comparative Example 4)

The first adhesive composition was changed to DC126 made by New Tac Kasei, and the thickness was changed as shown in Table 1. The second adhesive composition was changed to DC121 made by New Tac Kasei, and the rest were followed and implemented. Example 1 A double-sided adhesive sheet was obtained in the same manner.

(Comparative example 5)

A single-layered double-sided adhesive sheet was obtained in the same manner as in Comparative Example 3 except that the first adhesive composition was SA037 manufactured by New Tac Kasei, and the thickness was changed as shown in Table 1.

(Comparative Example 6)

A single-layered double-sided adhesive sheet was obtained in the same manner as in Comparative Example 3 except that the first adhesive composition was NA017 manufactured by New Tac Kasei and the thickness was changed as shown in Table 1.

(Comparative Example 7)

A double-sided adhesive sheet was obtained in the same manner as in Comparative Example 4 except that the first adhesive composition was SA034 manufactured by New Tac Kasei and the thickness was changed as shown in Table 1.

(Evaluation) (UV transmittance)

The ultraviolet transmittance of the base material layer was measured using an ultraviolet-visible spectrometer (type: Solidspec 3700, manufactured by Shimadzu Corporation). Specifically, the specific transmittance at a wavelength of 370 nm was measured.

(Foaming resistance (outgassing resistance))

For the co-extruded film (trade name: MR58) of PC (polycarbonate resin) and PMMA (polymethyl methacrylate resin) manufactured by Mitsubishi Gas Chemical Company, screen printing was performed on the PC side to form a decorative printing layer. The thickness of the decorative printed layer is 20 μm.

Next, the double-sided adhesive sheets obtained in the examples and comparative examples were cut to a size of 55 mm × 80 mm, and the separator A was torn to form a decorative printing layer capable of bonding the first adhesive layer to the co-extruded film (MR58). Side state.

Then, the separator B was torn apart, the second adhesive layer was bonded to the glass plate, and an autoclave defoaming treatment was performed at 40 ° C, 0.5 MPa, and 30 minutes. The laminated body thus obtained was allowed to stand for 24 hours at 85 ° C and a relative humidity of 0 to 3%. After this endurance test, the laminated body was observed from the PC / PMMA co-extruded film surface side, and was implemented according to the following evaluation criteria Evaluation of the presence or absence of air bubbles.

○: There is no air bubble in the center of the laminated body (area 10 mm or more from the edge of the decorative layer).

Δ: Although there are bubbles in the center of the laminated body, the bubbles are less than 200 μm in diameter.

×: Large bubbles with a diameter of 200 μm or more were found in the center of the laminate.

(Step tracking)

The laminated body was produced according to the same method as the foaming resistance evaluation method, and after performing the defoaming treatment and durability test according to the same method as described above, the laminated body was observed from the PC / PMMA co-extruded film surface side, and the frame The presence or absence of air bubbles in the periphery of the print (including the decorative layer and the area less than 10 mm from the edge of the decorative layer) (step traceability) was evaluated in accordance with the following evaluation criteria.

○: There are no air bubbles around the frame printing.

(Triangle | delta): Although the bubble generate | occur | produced in the corner part printed on the outer frame, it did not generate | occur | produce in the periphery of a long side and a short side.

×: Bubbles appeared in the corners and the periphery of the two sides printed on the frame.

It is learned that the double-sided adhesive sheet system obtained in the example has excellent outgassing resistance and step tracking. On the other hand, the double-sided pressure-sensitive adhesive sheet obtained in the comparative example was unable to balance off-gassing resistance and step tracking.

Using the double-sided adhesive sheet obtained in the embodiment, a laminated body can also be produced. Tear off the release sheet on the first adhesive layer side of the double-sided adhesive sheet and attach it to the decorative base material layer with the decorative layer. Then, tear off the release sheet on the second adhesive layer side, and then apply the roll to the Display device.

10‧‧‧ substrate layer

12‧‧‧ the first adhesive layer

14‧‧‧Second adhesive layer

100‧‧‧ double-sided adhesive sheet

Claims (8)

A double-sided adhesive sheet is provided with a base material layer having a light transmittance of more than 50% at a wavelength of 370 nm, and a first adhesive layer provided on one side of the base material layer. Hardened; and a second adhesive layer, which is provided on the other side of the substrate layer and has a thickness of 5 μm or more and 75 μm or less. The double-sided adhesive sheet according to claim 1, wherein the first adhesive layer has an active energy ray hardening ability. The double-sided adhesive sheet according to claim 1 or 2, wherein the thickness of the first adhesive layer is 50 μm or more and 250 μm or less. For example, the double-sided adhesive sheet of claim 1 or 2, wherein the first adhesive layer is a decorative base material layer on which a part of the surface is provided with a decorative layer. For example, the double-sided adhesive sheet according to claim 1 or 2, wherein the second adhesive layer is bonded to a display device. A laminated body comprising a double-sided adhesive sheet according to any one of claims 1 to 5, a decorative base material layer laminated on the first adhesive layer, and a display laminated on the second adhesive layer. Device; wherein the decorative substrate layer is provided with a decorative layer on a part of the surface, and one surface provided with the decorative layer is bonded to the first adhesive layer. For example, the laminated body of claim 6 is further provided with a third adhesive layer and a surface covering layer; the third adhesive layer is provided on the decorative substrate layer, and the third adhesive layer is provided on the decorative substrate layer. The above surface covering layer. A method for manufacturing a laminated body, comprising: bringing the above-mentioned first adhesive layer of the double-sided adhesive sheet according to any one of claims 1 to 5 into contact with a surface of the decorative base material layer facing the decorative layer side, and the The decorative substrate layer is a step in which a decorative layer is provided on a part of a surface, and in this state, active energy rays are irradiated from the second adhesive layer side to completely harden the first adhesive layer; and A step of bonding the display device to the second adhesive layer.