TW201800235A - Adhesive sheet display and method for producing them - Google Patents

Abstract

The present invention provides an adhesive sheet which has an adhesive agent layer having a relatively higher film strength, and has excellent filling property and blister resistance; a display element which has excellent filling property and blister resistance; and methods of producing the same. According to the present invention, an adhesive sheet (1) includes an adhesive agent layer (11) for combining one display element constituent member (21) and another display element constituent member (22), wherein the adhesive agent layer (11) has a crosslinking structure formed by (A) a (meth)acrylate ester copolymer and (B) a thermal crosslinker, and is formed by a UV-curable adhesive agent comprising (C) a UV-curable component, and (D) a photopolymerization initiator which has an absorbance of 0.3 or more at 380 nm in 0.1 mass% acetonitrile solution.

Description

Adhesive plate, display and manufacturing method of these articles

The present invention relates to an adhesive plate for bonding display constituent components, a display formed by bonding display constituent components, and a method for manufacturing the same.

In recent years, various mobile electronic devices such as mobile phones, smartphones, and tablet terminal devices have used displays including liquid crystal elements, light emitting diodes (LED elements), and organic electroluminescent (organic EL) elements. The display body (display) of the body module.

In such a display, a protective panel is usually provided on the front side of the display body module. A gap is provided between the protective panel and the display body module so that even when the protective panel is deformed by an external force, the deformed protective panel does not collide with the display body module.

However, when there is such a gap, that is, the air layer, the reflection loss of light caused by the difference in refractive index between the protective panel and the air layer and the difference in refractive index between the air layer and the display module is large, and there is a display. The problem of poor picture quality.

Therefore, there are proposals to improve the image quality of the display by using an adhesive layer to fill the gap between the protective panel and the display module. However, on the display module side of the protective panel, the frame-shaped printed layer is a squared step. Formula exists. When the adhesive layer does not follow the step, the adhesive layer floats near the step and a reflection loss of light is caused. Therefore, the above-mentioned adhesive layer system is required to have step-following followability.

In order to solve the above-mentioned problem, Patent Document 1 discloses a UV-crosslinkable adhesive sheet made of a (meth) acrylic copolymer containing a monomer, wherein the single system contains a UV-crosslinkable site (II) (Phenyl ketone structure), and the storage elastic modulus before and after UV cross-linking is specified. Such an ultraviolet-crosslinkable adhesive sheet is adhered to an adherend, and then is irradiated with ultraviolet rays to cause a crosslinking reaction to proceed and improve cohesion. The ultraviolet-crosslinkable adhesive sheet has a low storage elastic modulus at the stage of being adhered to the adherend, that is, the stage before the ultraviolet-crosslinking, so it is easy to follow the step of the adherend.

Prior art literature Patent literature

[Patent Document 1] Japanese Patent Laid-Open No. 2011-184582

However, the (meth) acrylic copolymer used in the ultraviolet-crosslinkable adhesive sheet of Patent Document 1 has a low crosslinking density and cohesive force before the ultraviolet-crosslinking, and therefore the ultraviolet-crosslinkable adhesive sheet has (Meth) acrylic copolymer adheres to the blade, or when the ultraviolet-crosslinkable adhesive sheet is stored, etc., and the (meth) acrylic copolymer oozes from the ultraviolet-crosslinkable adhesive sheet. Situation. In this way, the strength of the film of the ultraviolet-crosslinkable adhesive sheet in the patent document is low.

On the other hand, in the ultraviolet-crosslinkable adhesive sheet as described above, When an ultraviolet curable adhesive containing a common photopolymerization initiator is used, the ultraviolet curable adhesive is not sufficiently cured depending on the type of the protective panel, and causes problems under durable conditions. For example, when high-temperature and high-humidity conditions are implemented, air bubbles are generated near the step difference, or air is generated from the plastic plate that protects the panel, and air bubbles, floating, peeling, etc. are generated.

The present invention has been made in view of such a practical situation, and an object thereof is to provide an adhesive sheet having a high adhesive film strength and excellent step-following and blister resistance. Excellent displays from both parties, and methods of making these items

In order to achieve the above object, the first series of the present invention provides an adhesive sheet, which is an adhesive sheet provided with an adhesive layer for bonding a display component to another display component, and is characterized in that: The agent layer has a cross-linked structure composed of a (meth) acrylate copolymer (A) and a thermal cross-linking agent (B), and contains a UV-curable component (C) and a concentration of 0.1% by mass. The acetonitrile solution is composed of an ultraviolet curable adhesive with a photopolymerization initiator (D) having an absorbance of 0.3 or more at a wavelength of 380 nm (Invention 1).

In the adhesive sheet of the above-mentioned invention (Invention 1), since the adhesive system constituting the adhesive layer is thermally crosslinked, the strength of the film of the adhesive layer is high. In addition, since the adhesive layer contains a specific photopolymerization initiator (D), even when one display constituent member and / or other display constituent members contain ultraviolet absorbers, the adhesive layer can pass ultraviolet rays. It is sufficiently hardened by irradiation and has excellent step-followability and foam resistance.

In the above invention (Invention 1), the gel fraction of the adhesive is It is preferably 30% or more and 70% or less (Invention 2).

In the above-mentioned inventions (Inventions 1, 2), it is preferable that at least one of the aforementioned one display constituent member and the other display constituent member contains an ultraviolet absorber (Invention 3).

In the above-mentioned inventions (Inventions 1 to 3), it is preferable that the aforementioned one display body constituent member has a step at least on a surface to be bonded (Invention 4).

In the above invention (Inventions 1 to 4), the adhesive sheet is provided with two release sheets, and the adhesive layer is preferably held by the release sheet so as to be in contact with the release surface of the two release sheets (Invention 5) ).

The second aspect of the present invention provides a method for manufacturing an adhesive sheet, which is a method for manufacturing an adhesive sheet including an adhesive layer for bonding a display component to another display component, and is characterized by: By photopolymerization containing a (meth) acrylate copolymer (A), a thermal crosslinking agent (B), an ultraviolet curable component (C), and an acetonitrile solution having a concentration of 0.1% by mass at a wavelength of 380 nm and an absorbance of 0.3 or more The adhesive composition of the initiator (D) is applied and thermally cross-linked to form a UV-curable adhesive layer (Invention 6).

A third aspect of the present invention provides a display body including a display body constituent member, other display body constituent members, and a cured adhesive layer that adheres the aforementioned one display body constituent member and the other display body constituent member to each other. The display is characterized in that the cured adhesive layer has a crosslinked structure composed of a (meth) acrylate copolymer (A) and a thermal crosslinking agent (B), and contains a UV-curable component (C) and an adhesive of a photopolymerization initiator (D) having an absorbance of 0.3 or more at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass (Invention 7).

A fourth aspect of the present invention provides a display body including a display body constituent member, other display body constituent members, and a cured adhesive layer that adheres the aforementioned one display body constituent member and the other display body constituent member to each other. The display is characterized in that the cured adhesive layer has a crosslinked structure composed of a (meth) acrylate copolymer (A) and a thermal crosslinking agent (B), and contains a UV-curable component (C) It consists of the adhesive agent whose gel fraction of the said adhesive layer after hardening is 40%-95% (invention 8).

The fifth aspect of the present invention provides a method for manufacturing a display, characterized in that a display component is bonded to other display components by manufacturing the adhesive layer of the aforementioned adhesive sheet (Inventions 1 to 5). The laminated body is irradiated with ultraviolet rays to the adhesive layer of the laminated body to make the adhesive layer into a cured adhesive layer (Invention 9).

The film strength of the adhesive layer of the adhesive sheet of the present invention is high, and both the step-following property and the foam resistance are excellent. In addition, both the step-following property and the foam resistance of the display body of the present invention are excellent. Moreover, according to the method of the present invention, it is possible to manufacture the adhesive plates and display bodies.

1‧‧‧ Adhesive sheet

11‧‧‧ Adhesive layer

12a, 12b ‧‧‧ peeling sheet

2‧‧‧ Display

11’‧‧‧ Adhesive layer after hardening

21‧‧‧The first display component

22‧‧‧Second display component

3‧‧‧print layer

FIG. 1 is a cross-sectional view of an adhesive plate according to an embodiment of the present invention.

Fig. 2 is a sectional view of a laminated body according to an embodiment of the present invention.

Forms used to implement the invention

Hereinafter, embodiments of the present invention will be described.

(Adhesive plate)

The adhesive sheet of this embodiment is an adhesive sheet provided with an adhesive layer for bonding a display component to another display component. The display body and display body constituent members will be described later.

As shown in FIG. 1, as an example, the adhesive sheet 1 of this embodiment is composed of: two peeling sheets 12a, 12b; and a contact with the peeling surfaces of the two peeling sheets 12a, 12b. The adhesive layer 11 is held by the two release sheets 12a and 12b. In addition, the peeling surface of a release sheet in this specification means the surface which has peelability in a peeling sheet, including the surface which performed the peeling process, and the surface which also showed peelability without the peeling process.

Adhesive layer

The adhesive layer 11 has a cross-linked structure composed of a (meth) acrylate copolymer (A) and a thermal cross-linking agent (B), and contains a UV-curable component (C) and a concentration of The 0.1% by mass acetonitrile solution has a wavelength of 380 nm and an ultraviolet curable adhesive having a photopolymerization initiator (D) having an absorbance of 0.3 or more. In other words, the above-mentioned adhesive layer 11 is composed of a wavelength containing a (meth) acrylate copolymer (A), a thermal crosslinking agent (B), an ultraviolet curable component (C), and an acetonitrile solution at a concentration of 0.1% by mass. An ultraviolet curable adhesive made by thermally crosslinking an adhesive composition of a photopolymerization initiator (D) having an absorbance of 380 nm or more of 0.3 (hereinafter referred to as "adhesive composition P"). In addition, in this specification, (meth) acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms.

As described above, the adhesive layer 11 on the adhesive sheet 1 is composed of an adhesive obtained by thermally cross-linking the adhesive composition P. The adhesive is composed of A cross-linked structure composed of a (meth) acrylate copolymer (A) and a thermal cross-linking agent (B). On the other hand, the ultraviolet-curable component (C) is not hardened and is present in an adhesive in a state where it is formulated in the adhesive composition P. This ultraviolet curable component (C) is polymerized and cured when the adhesive layer 11 is irradiated with ultraviolet rays during use of the adhesive sheet 1 (after the adherend is adhered).

In the adhesive sheet 1 of this embodiment, the adhesive system constituting the adhesive layer 11 is thermally cross-linked. Since it has a certain degree of crosslinking density and a predetermined cohesive force, the adhesive layer 11 has a high film strength. Therefore, for example, when cutting an adhesive sheet, etc., the problem that an adhesive adheres to a blade etc. can be suppressed. In addition, it is possible to suppress bleeding of the adhesive from the adhesive layer 11 during storage of the adhesive sheet 1 or the like.

In addition, since the adhesive layer 11 of the adhesive sheet 1 of the present embodiment is softer in the stage before being hardened by ultraviolet radiation, when the adhesive sheet 1 is attached to a display constituent member having a step, The adhesive layer 11 can easily follow the step difference, and can suppress generation of a gap, floating, and the like near the step difference.

On the other hand, when the adhesive sheet 1 of this embodiment is used, after a display constituent member is bonded to other display constituent members through the adhesive layer 11 of the adhesive sheet 1, the display constituent member or The other display body constitutes a member and irradiates the adhesive layer 11 with ultraviolet rays and hardens the adhesive layer 11 to become a cured adhesive layer (in the second figure described later, the cured adhesive layer 11 '). Thereby, even when the obtained laminated body (display body) is left for 72 hours under high temperature and high humidity conditions, for example, 85 ° C. and 85% RH conditions, it is possible to suppress generation of bubbles, floating, peeling, and the like near the step. In addition, it is possible to suppress generation of bubbles, floating, peeling, and the like at the interface between the display component and the cured adhesive layer. Foaming. That is, the adhesive sheet 1 of this embodiment is excellent in the initial stage following property, and the stage following property and foam resistance under high temperature and high humidity conditions.

Here, when one of the above display constituent members and / or other display constituent members contains an ultraviolet absorber, a conventional photopolymerization initiator, such as 1-hydroxycyclohexylphenyl ketone, is used for the adhesive to transmit light. When one of the display body constituent members or other display body constituent members irradiates the adhesive layer with ultraviolet rays, ultraviolet rays of a wavelength used to crack the photopolymerization initiator are absorbed in the display body constituent members by the ultraviolet absorber, resulting in light. Cracking of the polymerization initiator is hindered. As a result, the curing reaction of the ultraviolet curable component does not proceed well, and the curing of the adhesive layer becomes insufficient. Therefore, the adhesive layer system is inferior in step-followability and foam resistance under high temperature and high humidity conditions. On the other hand, the adhesive layer 11 of the adhesive sheet 1 of this embodiment contains a photopolymerization initiator (D) having an absorbance of 0.3 or more at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass. At this time, even if the adhesive layer 11 is irradiated with ultraviolet rays through the display body constituting member containing the ultraviolet absorber, ultraviolet rays of a wavelength (long wavelength) for cracking the photopolymerization initiator (D) are not formed by the display body. Since the ultraviolet absorber is absorbed in the member, the photopolymerization initiator (D) is cracked without any problem. As a result, the curing reaction of the ultraviolet curable component (C) progresses well, and the adhesive layer 11 is sufficiently cured. Thereby, the obtained laminated body (display body) becomes the one which has the excellent step-following property and foam resistance under high temperature and high humidity conditions. That is, when the adhesive sheet 1 of this embodiment is used, even when one display body constituent member and / or other display body constituent members contain an ultraviolet absorber, they have excellent step-followability and resistance to high temperature and humidity. Bubble.

(1) (meth) acrylate copolymer (A)

The (meth) acrylate copolymer (A) is a monomer unit constituting the polymer, and a reactive group-containing monomer containing a reactive group that reacts with the thermal crosslinking agent (B) in the molecule is good. The reactive group derived from the reactive group-containing monomer is capable of reacting with the thermal cross-linking agent (B) to form a cross-linked structure (three-dimensional network structure) to form an adhesive layer 11 having a high film strength.

Examples of the reactive group-containing monomer include a monomer having a hydroxyl group in the molecule (a hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (a carboxyl group-containing monomer), and an amine in the molecule. A monomer (such as an amine group-containing monomer) is preferred. Among these, a hydroxyl-containing monomer which is excellent in reactivity with the thermal crosslinking agent (B) and has less adverse effects on an adherend is particularly preferred. Further, from the viewpoint that the required cohesive force can be exhibited even if the weight average molecular weight of the (meth) acrylate copolymer (A) is low, a carboxyl group-containing monomer is preferred.

Examples of the hydroxyl-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and (meth) acrylic acid 2 -Hydroxybutyl (meth) acrylate, etc., such as hydroxybutyl, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like. Particularly, in terms of the reactivity with the thermal crosslinking agent (B) of the hydroxyl group of the obtained (meth) acrylate copolymer (A), and the copolymerizability with other monomers, it is (meth) 2-hydroxyethyl acrylate and 4-hydroxybutyl (meth) acrylate are preferred, and 2-hydroxyethyl (meth) acrylate is particularly preferred. These may be used alone or in combination of two or more.

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Especially in terms of reactivity with the thermal cross-linking agent (B) at the carboxyl group of the obtained (meth) acrylate copolymer (A), and copolymerizability with other monomers, Acrylic is preferred. These may be used alone or in combination of two or more.

Examples of the amine-group-containing monomer include aminoethyl (meth) acrylate and n-butylamino (meth) acrylate. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A) has a lower limit as a monomer unit constituting the polymer and a hydroxyl-containing monomer, and preferably contains 3% by mass or more, and particularly contains 10% by mass or more. It is more preferable to contain 15 mass% or more. The (meth) acrylic acid ester copolymer (A) preferably has an upper limit of 35% by mass or less of a hydroxyl-containing monomer as the monomer unit of the polymer, and more preferably 30% by mass or less of the monomer unit. Particularly preferred is a content of 25% by mass or less. When the (meth) acrylic acid ester copolymer (A) contains a hydroxyl-containing monomer as the monomer unit in the above amount, the obtained adhesive can form a good crosslinked structure and obtain an adhesive with high film strength. At the same time as the layer 11, a predetermined amount of a hydroxyl group remains in the adhesive. The hydroxyl group is a hydrophilic group. When such a hydrophilic group is present in the adhesive in a predetermined amount, even if the adhesive is placed under high temperature and high humidity conditions, the compatibility with the moisture invading the adhesive is good under the high temperature and high humidity conditions. As a result, when it is returned to normal temperature and humidity, it is possible to suppress whitening of the adhesive (having excellent resistance to moist heat and whitening).

When the (meth) acrylate copolymer (A) contains a carboxyl group-containing monomer as a monomer unit constituting the polymer, the (meth) acrylate copolymer (A) has a lower limit value of 5 The mass of the carboxyl group-containing monomer is preferably at least 7% by mass, and more preferably at least 10% by mass. The (meth) acrylate copolymer (A) preferably has a carboxyl group-containing monomer containing 30% by mass or less as a monomer unit constituting the polymer. The content is preferably 20% by mass or less, and more preferably 15% by mass or less. When the (meth) acrylic acid ester copolymer (A) contains the carboxyl group-containing monomer as the monomer unit in the above-mentioned amount, the obtained adhesive can form a good cross-linked structure and obtain an adhesive layer with high film strength 11 .

The (meth) acrylate copolymer (A) preferably does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer. Because the carboxyl group is an acid component, by not containing a carboxyl group-containing monomer, it is possible to suppress defects caused by an acid on an object to be adhered to the adhesive, such as a transparent conductive film such as indium tin oxide (ITO) or a metal film. In this case, such defects (corrosion, resistance change, etc.) due to acid can be suppressed. However, as long as such a defect does not occur, a predetermined amount of a carboxyl group-containing monomer can be allowed. Specifically, in the (meth) acrylate copolymer (A), in terms of monomer units, less than 5 mass% of a carboxyl group-containing monomer is allowed, preferably 2 mass% or less, and particularly preferably 0.1. Amount below mass%.

The (meth) acrylic acid ester copolymer (A) exhibits better adhesion by using an alkyl (meth) acrylic acid having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer. Examples of the alkyl (meth) acrylate having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) ) N-butyl acrylate, n-amyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n- (meth) acrylate Cumester, n-dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl stearate (meth) acrylate, and the like. In particular, from the viewpoint of improving adhesion, (meth) acrylates having 1 to 8 carbon atoms in the alkyl group are preferred, and n-butyl (meth) acrylate or (meth) acrylic acid 2- Ethylhexyl is particularly preferred. Also, these can be used alone or in groups Use 2 or more types together.

The (meth) acrylate copolymer (A) is preferably an alkyl (meth) acrylate having 1 to 20 carbon atoms having an alkyl group of 40% by mass or more as a monomer unit constituting the polymer. 50% by mass or more is particularly preferable, and 60% by mass or more is more preferable. When the (meth) acrylic acid alkyl ester is contained in an amount of 40% by mass or more, suitable adhesion can be imparted to the (meth) acrylic acid ester copolymer (A). Moreover, it is preferable to contain the alkyl (meth) acrylate whose alkyl carbon number is 1-20 from 90 mass% or less, it is particularly preferable to contain 80 mass% or less, and it is more preferable to contain 70 mass%. By setting the content of the (meth) acrylic acid alkyl ester to 90% by mass or less, a required amount of other monomer components can be introduced into the (meth) acrylic acid ester copolymer (A).

The (meth) acrylic acid ester copolymer (A) preferably contains a monomer (alicyclic structure-containing monomer) having an alicyclic structure in the molecule as a monomer unit constituting the copolymer. Since the alicyclic structure-containing unit has a relatively high volume, it is presumed that the presence of the polymer in the polymer can increase the interval between the polymers, and can make the obtained adhesive have excellent flexibility. Therefore, the (meth) acrylate polymer (A) is an adhesive obtained by cross-linking the adhesive composition P by using an alicyclic structure-containing monomer as a constituent monomer unit, and has a more excellent initial stage. Segment followers.

The carbocyclic ring of the alicyclic structure in the alicyclic structure-containing monomer may be a saturated structure or a portion having an unsaturated bond. The alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as a bicyclic ring or a tricyclic ring. From the viewpoint of increasing the distance between the obtained (meth) acrylate copolymers (A) and effectively exhibiting the flexibility of the adhesive, the alicyclic structure is a polycyclic alicyclic structure. The structure (polycyclic structure) is preferred. And, considering (A The compatibility of the acrylate) acrylate copolymer (A) with other components. The above-mentioned polycyclic structure is particularly preferably bicyclic to tetracyclic. In addition, as described above, from the viewpoint of effectively exerting the softening effect of the adhesive, the number of carbons in the alicyclic structure (refers to the total number of carbons in the portion forming the ring, and when plural rings exist independently, (Referring to the total carbon number) is usually 5 or more, particularly preferably 7 or more. On the other hand, the upper limit of the number of carbons of the alicyclic structure is not particularly limited, and like the above, from the viewpoint of compatibility, it is preferably 15 or less, and particularly preferably 10 or less.

Examples of the alicyclic structure include a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton, an isofluorenyl skeleton, a cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononane skeleton, Cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.), cycloolefin skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornane diene skeleton, cubic alkanes ( A cubane skeleton, a basketane skeleton, a housane skeleton, a helical skeleton, etc., especially a dicyclopentadiene skeleton (carbon number of an alicyclic structure) containing a more excellent durability; 10 ), An adamantane skeleton (carbon number of the alicyclic structure: 10) or an isofluorenyl skeleton (carbon number of the alicyclic structure: 7) is preferable, and an isofluorenyl skeleton is particularly preferable.

The alicyclic structure-containing monomer is preferably a (meth) acrylic acid ester monomer containing the above-mentioned skeleton, and specific examples include cyclohexyl (meth) acrylate and dimethacrylate Cyclopentyl, Adamantane (meth) acrylate, Isoamyl (meth) acrylate, Dicyclopentenyl (meth) acrylate, Dicyclopentenyloxy (meth) acrylate, etc., especially Dicyclopentyl (meth) acrylate, adamantane (meth) acrylate, or isoamyl (meth) acrylate is more preferable, and isoamyl (meth) acrylate is more preferable. . These may be used individually by 1 type, and may be used in combination of 2 or more type.

When the (meth) acrylate copolymer (A) contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer, the (meth) acrylate copolymer (A) contains 5% by mass The above-mentioned alicyclic structure-containing unit is preferable, and it is particularly preferable that the unit contains 8% by mass or more, and it is more preferable that the unit contains 10% by mass or more. The (meth) acrylate copolymer (A) preferably contains a monomer having an alicyclic structure of 40% by mass or less as a monomer unit constituting the polymer, and particularly preferably contains 30% by mass or less of the monomer unit. Preferably, the content is more preferably 20% by mass or less. When the content of the alicyclic structure-containing unit is in the above-mentioned range, the initial stage difference followability of the obtained adhesive becomes more excellent.

The (meth) acrylic acid ester copolymer (A) preferably contains a monomer (a nitrogen atom-containing monomer) having a nitrogen atom in the molecule as a monomer unit constituting the copolymer. In addition, an amine group-containing monomer as a reactive group-containing monomer has been exemplified as being removed from the nitrogen atom-containing monomer. By using a nitrogen atom-containing monomer as a structural unit in the polymer, it is possible to promote the reaction between the acrylate copolymer (A) and the thermal crosslinking agent (B), or to impart polarity to the adhesive and increase the cohesive force of the adhesive itself. .

Examples of the nitrogen atom-containing monomer include a monomer having a tertiary amine group, a monomer having a sulfonium group, a monomer having a nitrogen-containing heterocyclic ring, and the like, and particularly a monomer having a nitrogen-containing heterocyclic ring. The body is better.

Examples of the monomer having a nitrogen-containing heterocyclic ring include N- (meth) acrylfluorenylmorpholin, N-vinyl-2-pyrrolidone, and N- (meth) acrylfluorinylpyrrolidone , N- (meth) acrylfluorenylpiperidine, N- (meth) acrylfluorenyl pyrrolidine, N- (meth) acrylfluorenyl acrylpropane, acrylpropanyl (meth) acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide, etc., especially N- (meth) acrylfluorenyl morpholin, which exhibits more excellent adhesion, and N-acrylfluorenyl morphin Lin Weijia and so on.

Further, as the monomer having a nitrogen atom other than the monomer having a nitrogen-containing heterocyclic ring, for example, (meth) acrylamide, N-methyl (meth) acrylamide, or N-hydroxymethyl (Meth) acrylamide, N-third butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-ethyl (meth) acrylamine Amine, N, N-dimethylaminopropyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-phenyl (meth) acrylamide, dimethylaminopropyl (Meth) acrylamide, N-vinylcaprolactam, dimethylaminoethyl (meth) acrylate, and the like.

These nitrogen atom-containing monomers may be used alone or in combination of two or more.

When the (meth) acrylate copolymer (A) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer, the (meth) acrylate copolymer (A) contains 1 mass% or more of The nitrogen atom is preferably a monomer, particularly preferably containing 2% by mass or more, and further preferably containing 5% by mass or more. The (meth) acrylic acid ester copolymer (A) preferably uses a monomer containing a nitrogen atom of 40% by mass or less as a monomer unit constituting the polymer, and particularly preferably contains 25% by mass or less. The content is more preferably 15% by mass or less. When the content of the nitrogen atom-containing monomer is within the above range, the cohesive force of the obtained adhesive is effectively increased.

The (meth) acrylic acid ester copolymer (A) may contain other monomer as a monomer unit which comprises this polymer as needed. The other monomer is preferably a monomer containing a non-reactive functional group. Examples of such other monomers include methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate (Meth) acrylic acid alkoxyalkyl esters, vinyl acetate, styrene, and the like. These may be used alone or in combination of two or more.

The polymerization state of the (meth) acrylate copolymer (A) may be a random copolymer or a block copolymer.

The weight average molecular weight of the (meth) acrylate polymer (A) is preferably 100,000 or more, particularly preferably 200,000 or more, and more preferably 300,000 or more. When the lower limit of the weight average molecular weight of the (meth) acrylate polymer (A) is the above or higher, the film strength of the obtained adhesive becomes higher. The weight average molecular weight of the (meth) acrylate polymer (A) is preferably 900,000 or less, particularly 800,000 or less, particularly preferably 700,000 or less as the upper limit. When the upper limit of the weight average molecular weight of the (meth) acrylate polymer (A) is the above or below, the step-followability of the obtained adhesive becomes more excellent. In addition, the weight average molecular weight in this specification is a standard polystyrene conversion value measured by the gel permeation chromatography (GPC) method.

Moreover, in the adhesive composition P, (meth) acrylate copolymer (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

(2) Thermal crosslinking agent (B)

When the adhesive composition P containing the thermal cross-linking agent (B) is heated, the thermal cross-linking agent (B) cross-links the (meth) acrylate copolymer (A) to form a three-dimensional network structure. Thereby, the adhesive layer 11 with high film strength can be obtained.

唑啉系交聯劑、 金屬烷氧化物系交聯劑、金屬鉗合物系交聯劑、金屬鹽系交聯劑、銨系交聯等。上述之中，(甲基)丙烯酸酯共聚物(A)所具有之反應性基為羥基時，係以使用與羥基具有優異的反應性之異氰酸酯系交聯劑為佳，(甲基)丙烯酸酯共聚物(A)所具有之反應性基為羧基時，係以使用與羧基具有優異的反應性之環氧系交聯劑為佳。又，熱交聯劑(B)能夠單獨1種、或組合2種以上而使用。 The thermal crosslinking agent (B) may be one that reacts with a reactive group of the (meth) acrylate copolymer (A), and examples thereof include an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent. , Amine-based cross-linking agent, melamine-based cross-linking agent, acridine-based cross-linking agent, hydrazine-based cross-linking agent, aldehyde-based cross-linking agent,

An oxazoline-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal clamp complex-based crosslinking agent, a metal salt-based crosslinking agent, an ammonium-based crosslinking agent, and the like. Among the above, when the reactive group of the (meth) acrylate copolymer (A) is a hydroxyl group, it is preferable to use an isocyanate-based crosslinking agent having excellent reactivity with the hydroxyl group, and the (meth) acrylate When the reactive group of the copolymer (A) is a carboxyl group, it is preferable to use an epoxy-based crosslinking agent having excellent reactivity with the carboxyl group. Moreover, a thermal crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more types.

The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, and isophorone. Alicyclic polyisocyanates, such as diisocyanates, hydrogenated diphenylmethane diisocyanates, and the like, biuret bodies, trimeric isocyanates, and further ethylene glycol, propylene glycol, neopentyl alcohol, and trimethylolpropane , Castor oil and other reactants with low-molecular active hydrogen compounds. In particular, from the viewpoint of reactivity with a hydroxyl group, it is an aromatic polyisocyanate modified with trimethylolpropane, particularly toluene diisocyanate modified with trimethylolpropane, and benzenediene modified with trimethylolpropane. Methyl diisocyanate is preferred.

Examples of the epoxy-based crosslinking agent include 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, N ', N'-tetraepoxypropyl-methane Xylylenediamine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, bicyclic Oxypromine, etc. Especially from the viewpoint of reactivity with a carboxyl group, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane is preferred.

The content of the thermal crosslinking agent (B) in the adhesive composition P is preferably 0.01 parts by mass or more and 0.05 parts by mass or more with respect to 100 parts by mass of the (meth) acrylate copolymer (A). It is particularly preferred, and more preferably 0.1 parts by mass or more. The content is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and further preferably 0.4 parts by mass or less. When the content of the thermal cross-linking agent (B) is in the above range, the obtained adhesive system has sufficient flexibility, can exhibit good cohesive force, and obtains an adhesive layer 11 having a high film strength.

(3) UV-curable component (C)

When the adhesive composition P contains an ultraviolet-curable component (C), the formed adhesive layer 11 becomes an ultraviolet-curable adhesive layer. This adhesive layer 11 is adhered to an adherend, and is cured by irradiating ultraviolet rays, and it is estimated that the ultraviolet curable components (C) are polymerized with each other, and the polymerized ultraviolet curable components (C) are entangled in (formerly) Group) a crosslinked structure (three-dimensional network structure) of the acrylate copolymer (A). Adhesives with this advanced structure are those that have excellent step-followability and foam resistance under high temperature and high humidity conditions.

The ultraviolet-curable component (C) is hardened by irradiating ultraviolet rays in the presence of a photopolymerization initiator (D) to be described later, and there is no particular limitation as long as the component having the above-mentioned effects can be obtained. The component may be a monomer or an oligosaccharide. Either a polymer or a polymer may be a mixture of these. In particular, a polyfunctional acrylate-based monomer having a molecular weight of less than 1,000 and having excellent compatibility with (meth) acrylate copolymer (A) and the like can be cited.

Examples of the polyfunctional acrylate monomer having a molecular weight of less than 1,000 include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and neopentyl glycol. Di (meth) acrylate, polyethylene glycol di (meth) propylene Enoate, neopentyl glycol adipic acid di (meth) acrylate, hydroxytrimethylacetic acid neopentyl glycol di (meth) acrylate, dicyclopentenyl di (meth) acrylate, hexane Lactone modified dicyclopentene di (meth) acrylate, ethylene oxide modified phosphate di (meth) acrylate, bis (acryloxyethyl) trimeric isocyanate, allyl cyclohexyl Bifunctional types such as di (meth) acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis [4- (2-propenyloxyethoxy) phenyl] fluorene, etc .; trihydroxy Methylpropane tri (meth) acrylate, dinepentaerythritol tri (meth) acrylate, propionic acid modified dinepentaerythritol tri (meth) acrylate, neopentaerythritol tri (meth) Acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, trimeric isocyanate (propylene ethoxyethyl) ester, ε-caprolactone modified trimeric isocyanate Trifunctional type such as (2- (meth) acryloxyethyl) ester; 4-functional type such as diglycerol tetra (meth) acrylate, neopentaerythritol tetra (meth) acrylate; propionic acid 5-functional type such as modified dipentaerythritol penta (meth) acrylate; Erxin 6-functional types such as pentaerythritol hexa (meth) acrylate, caprolactone-modified dineopentaerythritol hexa (meth) acrylate, and the like. Among the above, from the viewpoints of the step-followability and foam resistance of the obtained adhesive under high-temperature and high-humidity conditions, bis (acryloxyethyl) trimeric isocyanate and ginseng (acrylic acid) (Ethylethyl) trimeric isocyanate, ε-caprolactone-modified ginseng (2- (meth) acryloxyethyl) trimeric isocyanate, and other polyfunctional acrylate monomers containing a trimeric isocyanate structure in the molecule Preferably, a trifunctional or higher polyfunctional acrylate monomer containing a trimeric isocyanate structure in the molecule is preferred, and ε-caprolactone modified trimeric isocyanate (2- (meth) acrylic acid) Ethoxy) is particularly preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

As the ultraviolet-curable component (C), an ultraviolet-curable acrylate-based oligomer can be used. This acrylate-based oligomer is weight averaged Sub-quantities below 50,000 are preferred. Examples of such an acrylate oligomer include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, and polysilicon. Oxyacrylate and the like.

The weight average molecular weight of the acrylate-based oligomer is preferably 50,000 or less, more preferably 500 to 50,000, and further preferably 3,000 to 40,000. These acrylate type oligomers may be used individually by 1 type, and may be used in combination of 2 or more type.

In addition, as the ultraviolet curable component (C), an addition acrylate-based polymer in which a group having a (meth) acrylfluorenyl group is introduced into a side chain can also be used. Such an addition acrylic polymer is a copolymer of a (meth) acrylic acid ester and a monomer having a crosslinkable functional group in the molecule by using a (meth) acrylic acid ester and having a (meth) acrylfluorene group. A compound that reacts with a crosslinkable functional group is obtained by reacting a part of the crosslinkable functional group of the copolymer.

The weight average molecular weight of the addition acrylate-based polymer is preferably about 50,000 to 900,000, and particularly preferably about 100,000 to 500,000.

The ultraviolet curable component (C) can be selected from one of the aforementioned multifunctional acrylate monomers, acrylate oligomers, and addition acrylate polymers, and can be used in combination of two or more. It can also be used in combination with ultraviolet curing components other than these.

The content of the ultraviolet-curable component (C) in the adhesive composition P is relatively from the viewpoint that the obtained adhesive has excellent step-followability and foam resistance under high temperature and high humidity conditions. Based on 100 parts by mass of the (meth) acrylate copolymer (A), preferably 1 part by mass or more, and 2 parts by mass or more More preferably, 3 parts by mass or more is particularly preferred. On the other hand, from the standpoint of preventing crosslinking from becoming too tight, resulting in low adhesion and poor durability, the content is preferably 30 parts by mass or less, more preferably 15 parts by mass or less, and 10 parts by mass The following are particularly good.

(4) Photopolymerization initiator (D)

The photopolymerization initiator (D) in this embodiment is one having an absorbance of 0.3 or more at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass. When the adhesive constituting the adhesive layer 11 contains such a photopolymerization initiator (D), even when the adhesive layer 11 is irradiated with ultraviolet rays through a display member constituting member containing an ultraviolet absorber, the adhesive layer 11 (ultraviolet rays) The hardening component (C)) hardens well and has excellent step-followability and foam resistance under high temperature and high humidity conditions.

From the viewpoint described above, the absorbance of the photopolymerization initiator (D) at a wavelength of 380 nm is preferably 0.5 or more, and particularly preferably 1.0 or more. The upper limit of the absorbance is not particularly limited, but is usually preferably 2.5 or less, and particularly preferably 2.0 or less. When the absorbance is greater than 2.5, the UV-curable component (C) undergoes a curing reaction due to the photopolymerization initiator (D) in accordance with the ambient light such as a fluorescent lamp during the formation or storage of the adhesive sheet. Low level of follow-up. Here, the method for measuring the absorbance of the photopolymerization initiator (D) is as disclosed in a test example described later.

The photopolymerization initiator (D) is an absorption maximum wavelength of an absorbance at a wavelength of 200 to 500 nm in an acetonitrile solution having a concentration of 0.1% by mass, preferably 350 nm or more, particularly 370 nm or more, and further preferably 380 nm or more. good. In addition, when there are a plurality of absorption maximum wavelengths of absorbance having a wavelength of 200 to 500 nm, at least one absorption maximum wavelength may be in the above range. With this, in When the ultraviolet light is irradiated to the pressure-sensitive adhesive layer 11 when the display body is constituted by an ultraviolet absorber, the hardenability of the pressure-sensitive adhesive layer 11 (ultraviolet-curable component (C)) is further improved, and it is more excellent in high temperature and high humidity Those who have step-following and blister resistance. On the other hand, the upper limit of the absorption maximum wavelength is not particularly limited. From the viewpoint of preventing the curing reaction from occurring when the adhesive layer 11 is stored in ambient light, it is preferably 450 nm or less, and particularly preferably 410 nm or less. Furthermore, it is more preferably 405 nm or less.

Examples of such a photopolymerization initiator (D) include 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide, and bis (2,4,6-trimethylbenzyl) Fluorenyl) -phenylphosphine oxide and the like. These may be used alone or in combination of two or more.

In addition, in the adhesive (adhesive composition P) of the present embodiment, the photopolymerization initiator (D) and a photopolymer having an absorbance of less than 0.3 at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass can be polymerized Initiator (hereinafter referred to as "photopolymerization initiator (ND)") in combination. Examples of such a photopolymerization initiator (ND) include 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, and 2,2-dimethylamine. Oxy-1,2-diphenylethane-1-one and the like. At this time, with respect to 100 parts by mass of the photopolymerization initiator (D), the proportion of the photopolymerization initiator (ND) is preferably 50 to 150 parts by mass, particularly preferably 75 to 125 parts by mass, and further 80 ~ 120 parts by mass is preferred.

The photopolymerization initiator (D) is 2 to 15 parts by mass with respect to 100 parts by mass of the ultraviolet curable component (C), and it is particularly preferable to use the amount in the range of 4 to 12 parts by mass.

(5) Silane coupling agent (E)

It is preferable that the adhesive composition P further contains a silane coupling agent (E). borrow Therefore, when the adherend has a glass member, the adhesion between the obtained adhesive and the glass member is improved. In addition, even if the adherend is a plastic plate, the adhesiveness of the obtained adhesive system and the plastic plate is improved. Thereby, the obtained adhesive becomes a person having more excellent step-followability under high temperature and high humidity conditions.

The silane coupling agent (E) is an organosilicon compound having at least one alkoxysilyl group in the molecule, and the one having good compatibility with the (meth) acrylate copolymer (A) and having light transmittance is good.

Examples of such a silane coupling agent (E) include a polymerizable unsaturated group-containing silicon such as vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, and the like. Compounds, silicon compounds with epoxy structures such as 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-hydrothiopropyl Hydrogenthio-containing silicon compounds such as trimethoxysilane, 3-hydrothiopropyltriethoxysilane, 3-hydrothiopropyldimethoxymethylsilane, and 3-aminopropyltrimethoxysilane Amine-containing silicon compounds, such as N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane , 3-chloropropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or at least one of these, with methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxy Condensates of silicon compounds containing alkyl groups such as alkylsilane, ethyltrimethoxysilane, and the like. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the silane coupling agent (E) in the adhesive composition P is preferably 0.01 parts by mass or more relative to 100 parts by mass of the (meth) acrylate copolymer (A), and more preferably 0.05 parts by mass or more Preferably, it is more preferably 0.1 parts by mass or more. The content is preferably 1 part by mass or less, and preferably 0.5 part by mass or less. Particularly preferred is 0.3 mass parts or less.

(6) Various additives

Various types of additives commonly used in acrylic adhesives can be added to the adhesive composition P, such as ultraviolet absorbers, antistatic agents, adhesion-imparting agents, antioxidants, light stabilizers, softeners, fillers, Refractive index adjuster, etc. In addition, a polymerization solvent and a diluent to be described later are added so as not to be included in the adhesive composition P.

(7) Manufacture of adhesive composition

The adhesive composition P is produced from a (meth) acrylate copolymer (A), and the obtained (meth) acrylate copolymer (A), a thermal crosslinking agent (B), and an ultraviolet curable component ( C) and the photopolymerization initiator (D) can also be produced by adding a silane coupling agent (E) and / or an additive, if necessary.

The (meth) acrylate copolymer (A) can be produced by polymerizing a mixture of monomers constituting a polymer by a general radical polymerization method. The polymerization of the (meth) acrylate copolymer (A) can be performed by a solution polymerization method or the like using a polymerization initiator as necessary. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more kinds may be used in combination.

Examples of the polymerization initiator include azo compounds, organic peroxides, and the like, and two or more kinds may be used in combination. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), and 1,1'-azobis (cyclohexyl) Alkane 1-nitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile) ), Dimethyl 2,2'-azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2 -Methylolpropionitrile), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] and the like.

Examples of the organic peroxide include benzamyl peroxide, tert-butyl peroxide benzoate, cumene hydrogen peroxide, diisopropyl peroxide dicarbonate, and di-n-propyl peroxide dicarbonate. Bis (2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-butyl peroxytrimethylacetate, (3,5,5-trimethyl peroxide) Hexamidine), dipropylammonium peroxide, diethylammonium peroxide, and the like.

In the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by blending a chain transfer agent such as 2-hydrothiothioethanol.

After the (meth) acrylate copolymer (A) is obtained, a thermal crosslinking agent (B), an ultraviolet curable component (C), and photopolymerization are added to a solution of the (meth) acrylate copolymer (A). The initiator (D), the silane coupling agent (E), and the additives as necessary are sufficiently mixed to obtain an adhesive composition P.

(8) Formation of adhesive layer

The adhesive layer 11 is obtained by thermally crosslinking the adhesive composition P. That is, the cross-linking of the adhesive composition P is performed by heat processing. The heat treatment can be performed simultaneously with the drying treatment after the application of the adhesive composition P.

The heating temperature of the heat treatment is preferably 50 to 150 ° C, and particularly preferably 70 to 120 ° C. The heating time is preferably 10 seconds to 10 minutes, and particularly preferably 50 seconds to 2 minutes. In addition, it is particularly preferable that the curing period is set at about 1 to 2 weeks at room temperature (for example, 23 ° C., 50% RH) after the heat treatment.

By the above-mentioned heat treatment (and aging), the (meth) acrylate copolymer (A) can be well-crosslinked through the thermal crosslinking agent (B).

Thickness of the adhesive layer 11 (measured in accordance with JIS K7130 The lower limit is preferably 20 μm or more, more preferably 25 μm or more, particularly preferably 30 μm or more, and even more preferably 50 μm or more. When the lower limit value of the thickness of the adhesive layer 11 is 20 μm or more, the required adhesive force is easily exhibited. In addition, when the lower limit value of the thickness of the adhesive layer 11 is 30 μm or more, it is possible to ensure sufficient step-followability with respect to the normal step of the display component.

The upper limit of the thickness of the adhesive layer 11 is preferably 500 μm or less, more preferably 400 μm or less, and particularly preferably 300 μm or less. When the upper limit value of the thickness of the adhesive layer 11 is below or below, it will become a thing with favorable processability. The adhesive layer 11 may be formed of a single layer, or may be formed by laminating a plurality of layers.

(9) Gel fraction (before UV irradiation)

The lower limit of the gel fraction of the adhesive (before ultraviolet irradiation) constituting the adhesive layer 11 is preferably 30% or more, more preferably 40% or more, and particularly preferably 50% or more. When the lower limit value of the gel fraction of the adhesive before the ultraviolet irradiation is the above or more, the cohesive force of the adhesive layer 11 is improved and the film strength is high. The upper limit of the gel fraction of the adhesive before ultraviolet irradiation is preferably 70% or less, particularly preferably 65% or less, and even more preferably 60% or less. When the upper limit of the gel fraction of the adhesive before ultraviolet irradiation is the above or below, the adhesive does not become excessively hard and the initial step-followability is more excellent. The method for measuring the gel fraction of the adhesive (before ultraviolet irradiation) is disclosed in a test example described later.

2. Release sheet

As the release sheet 12a, 12b, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, or polyparaphenylene can be used. Ethylene dicarboxylate film, polynaphthalene Ethylene diformate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionic polymer resin film, ethylene ‧ (meth) acrylic copolymer film, ethylene ‧ (meth) acrylic acid Ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. Moreover, such a crosslinked film can also be used. Moreover, such a laminated film may be used.

It is preferable to perform a peeling process on the peeling surface (especially the surface which contacts the adhesive layer 11) of the said peeling sheet 12a, 12b. Examples of the release agent used in the release treatment include alkyd-based, polysiloxane-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. Among the release sheets 12a and 12b, one of the release sheets is a heavy release-type release sheet having a large release force and the other release sheet is a light-release type release sheet having a small release force. good.

The thickness of the release sheets 12a and 12b is not particularly limited, but is usually about 20 to 150 μm.

3. Adhesive sheet manufacturing

As a manufacturing example of the adhesive sheet 1, the coating liquid of the said adhesive composition P is apply | coated to the peeling surface of one release sheet 12a (or 12b), and it heat-processes, and the adhesive composition P is heat-crossed. After forming a coating layer, the peeling surface of the other release sheet 12b (or 12a) is laminated | stacked on this coating layer. When the coating layer requires a curing period, the coating layer directly becomes the adhesive layer 11 when the curing period is left, and when the curing period is not required. Thereby, the above-mentioned adhesive sheet 1 can be obtained. The conditions for heat treatment and aging are as described above.

As another manufacturing example of the adhesive sheet 1, the coating solution of the adhesive composition P is applied to the release surface of one of the release sheets 12a, and heat treatment is performed to thermally crosslink the adhesive composition P to form a coating. Coated Cloth release sheet 12a. Then, the coating liquid of the adhesive composition P is applied to the release surface of the other release sheet 12b, and heat treatment is performed to thermally crosslink the adhesive composition P to form a coating layer to obtain a coating layer. Of release sheet 12b. Then, the peeling sheet 12a with a coating layer and the peeling sheet 12b with a coating layer are bonded together so that both coating layers may contact each other. The above-mentioned laminated coating layer becomes the adhesive layer 11 directly when the curing period is required, or when the curing period is left, and when the curing period is not required. Thereby, the above-mentioned adhesive sheet 1 can be obtained. According to this manufacturing example, even when the adhesive layer 11 is thick, it can be stably manufactured.

As a method for applying the coating liquid of the adhesive composition P, for example, a bar coating method, a blade coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like can be used. .

The adhesive sheet 1 of this embodiment is because the film strength of the adhesive layer 11 is high. Therefore, when the adhesive sheet 1 is subjected to cutting processing, etc., it is possible to prevent the adhesive from extruding on the cross section and causing the adhesive to adhere to the blade, etc. The problem. In addition, the adhesive sheet 1 can also be prevented from oozing out of the adhesive layer 11 during storage or the like.

[Display body]

As shown in FIG. 2, the display body 2 of this embodiment includes the following: a first display body structural member 21 (a display body structural member) having a step at least on the surface to be bonded; and a second display body The constituent members 22 (other display constituent members); and the hardened adhesive layer 11 ′, which are located between these and adhere the first display constituent member 21 and the second display constituent member 22 to each other. In the display body 2 of this embodiment, the first display body constituting member 21 has a step on the surface of the cured adhesive layer 11 'side, and is specifically formed by having the print layer 3. Segment difference.

The cured adhesive layer 11 'of the display body 2 is formed by curing the adhesive layer 11 of the adhesive sheet 1 by ultraviolet irradiation. This hardened adhesive layer 11 ′ is firstly composed of a (meth) acrylate copolymer (A) and a thermal cross-linking agent (B), and contains a UV-curable component (C ) And a photopolymerization initiator (D). It is estimated that the ultraviolet-curable component (C) after polymerization is entangled in a crosslinked structure composed of a (meth) acrylate copolymer (A) and a thermal crosslinking agent (B).

The photopolymerization initiator (D) contained in the adhesive constituting the hardened adhesive layer 11 'described above is a photopolymerization initiator (D) contained in the adhesive composition P, even if it is irradiated with ultraviolet rays. Crack and remain. Therefore, its content is not large, and it is usually preferably 0.00001% by mass to 0.1% by mass in the adhesive, and preferably 0.0001% by mass to 0.01% by mass.

The second hardened adhesive layer 11 ′ is a second one having a cross-linked structure composed of a (meth) acrylate copolymer (A) and a thermal cross-linking agent (B) and containing an ultraviolet curable component (C ) Is composed of an adhesive of a hardened product, and the gel fraction of the adhesive (after ultraviolet irradiation) is preferably 40% or more and 95% or less. Compared with the gel fraction of the adhesive constituting the adhesive layer 11 before the ultraviolet curing, the gel fraction of the adhesive constituting the adhesive layer 11 'after the curing is the ultraviolet curable component (C) which is cured by ultraviolet rays. And becomes higher.

When the adhesive layer 11 is irradiated with ultraviolet rays beyond a display constituent member that does not contain an ultraviolet absorber, the gel fraction of the adhesive constituting the cured adhesive layer 11 ′ is preferably 65% or more as the lower limit value. Above 70% is particularly good. In addition, the adhesive is passed over the constituent elements of the display body containing the ultraviolet absorber. When the adhesive layer 11 is irradiated with ultraviolet rays, the gel fraction of the adhesive constituting the cured adhesive layer 11 ′ is preferably 40% or more as the lower limit value, more preferably 60% or more, and 62% or more. Especially good. When the lower limit value of the gel fraction of the adhesive after ultraviolet irradiation is the above or more, the step-followability and foam resistance under the high-temperature and high-humidity conditions of the hardened adhesive layer 11 'of the display 2 are relatively high Outstanding.

On the other hand, when the adhesive layer 11 is irradiated with ultraviolet rays over a display constituent member that does not contain an ultraviolet absorber, the gel fraction of the adhesive constituting the cured adhesive layer 11 ′ is 90 as the upper limit. % Or less is preferable, 85% or less is particularly preferable, and 80% or less is more preferable. In addition, when the adhesive layer 11 is irradiated with ultraviolet rays beyond a display constituent member containing an ultraviolet absorber, the gel fraction of the adhesive constituting the cured adhesive layer 11 'is 90% or less as the upper limit. It is particularly preferable that it is 80% or less, and more preferably 75% or less. When the upper limit of the gel fraction of the adhesive after ultraviolet irradiation is the above or below, it is possible to prevent the adhesive force of the adhesive layer 11 'after curing from being lowered and the durability from being deteriorated. The measurement method of the gel fraction of this adhesive (after ultraviolet irradiation) is as disclosed in the test example mentioned later.

As the lower limit, the step-following ratio (%) shown by the following formula of the hardened adhesive layer 11 'is preferably 20% or more, particularly preferably 25% or more, and more preferably 30% or more. The upper limit value of the step-following rate is not particularly limited, but it is usually preferably 80% or less, and particularly preferably 70% or less.

Step-following rate (%) = {(After the endurance test is scheduled, there is no bubble, floating, peeling, etc., and the landfill can maintain the state of the land (μm)) / (thickness of the adhesive layer)} × 100

The test method of the step-following rate is as disclosed in a test example described later.

Since the step-following rate of the hardened adhesive layer 11 'is in the above range, the hardened adhesive layer 11' can follow the step of the display body constituent member (the first display body constituent member 21) well after a durability test and can It is possible to suppress the occurrence of bubbles, floating, peeling, etc. in the vicinity of the step, and it is possible to suppress the reflection loss of the light generated thereby.

Examples of the display body 2 include a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescent (organic EL) display, an electronic paper, and the like, and may also be a touch panel. The display body 2 may be a component constituting a part of these.

The first display body constituent member 21 is preferably a protective panel composed of a laminated body or the like in addition to a glass plate, a plastic plate, and the like. At this time, the printed layer 3 is generally formed in a frame shape on the hardened adhesive layer 11 'side of the first display body constituent member 21.

The first display body constituent member 21, particularly the first display body constituent member 21 as a protective panel, preferably contains an ultraviolet absorber. At this time, the display body 2 becomes a person having excellent light resistance. Even if the ultraviolet light is exposed to the manufactured display body 2 from the side of the first display member 21, the cured adhesive layer 11 'and its lower layer can be suppressed. The second display body constituent member 22 is deteriorated. In particular, the adhesive layer 11 'after curing can maintain excellent step-followability and foam resistance.

The glass plate is not particularly limited, and examples thereof include chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, barium and strontium glass, aluminosilicate glass, lead glass, borosilicate glass, and barium boron. Silica glass and so on. The thickness of the glass plate is not particularly limited, but is usually 0.1 to 5 mm, and preferably 0.2 to 2 mm.

The plastic plate is not particularly limited, and examples thereof include an acrylic plate and a polycarbonate plate. The thickness of the plastic plate is not particularly limited, but is usually 0.2 to 5 mm, preferably 0.4 to 3 mm.

In addition, various functional layers (transparent conductive film, metal layer, silicon oxide layer, hard coat layer, anti-glare layer, etc.) may be provided on one or both sides of the glass plate and the plastic plate, and optical members may be laminated. In addition, the transparent conductive film and the metal layer may be patterned.

The second display body constituent member 22 is an optical member to be attached to the first display body constituent member 21, and is a display body module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module , Organic electro-excitation light (organic EL) module, etc.), an optical component as a part of the display body module, or a multilayer body including the display body module is preferable. In addition, the display body module system generally does not transmit ultraviolet rays.

Examples of the optical member include an anti-scattering film, a polarizing plate (polarizing film), a polarizer, a retardation plate (a retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, Diffusion film, transflective film, transparent conductive film, etc. Examples of the anti-scattering film include a hard-coated film formed by forming a hard-coat layer on one surface of a base film. The optical member may contain an ultraviolet absorber.

The material constituting the printing layer 3 is not particularly limited, and a known material for printing can be used. The thickness of the printing layer 3, that is, the lower limit of the height of the step, is preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 7 μm or more, and most preferably 10 μm or more. When the lower limit value is equal to or more than the above, it is possible to sufficiently ensure the shielding property that the circuit or the like cannot be viewed from the viewer side. The upper limit value is preferably 50 μm or less, more preferably 35 μm or less, and particularly preferably 25 μm or less. Preferably, it is more preferably 20 μm or less. With the upper limit value being the above or below, it is possible to prevent deterioration in the followability of the stepped adhesive layer 11 'to the printed layer 3 after curing.

The best aspect of the display body 2 is that the first display body constituent member 21 is a protective panel including a plastic plate containing an ultraviolet absorber, and the second display body constituent member 22 is a touch panel of a display body module that does not transmit ultraviolet rays. panel. In addition, the patterned transparent conductive film and the metal layer may exist in any part. Such a display body 2 is excellent in all of light resistance, step followability, and foam resistance.

As an example, the display body 2 is manufactured by peeling off the release sheet 12a on the adhesive sheet 1 and bonding the exposed adhesive layer 11 of the adhesive sheet 1 to the print layer 3 of the first display member 21 There are side faces. At this time, since the adhesive layer 11 has excellent initial step-followability, it is possible to suppress generation of gaps and floating near the step caused by the printed layer 3.

Next, the other peeling sheet 12 b of the adhesive layer 11 of the adhesive sheet 1 is peeled off, and the exposed adhesive layer 11 of the adhesive sheet 1 and the second display body constituent member 22 are adhered to obtain a laminated body. As another example, the bonding order of the first display body constituent member 21 and the second display body constituent member 22 may be changed.

Subsequently, the adhesive layer 11 in the laminated body is irradiated with ultraviolet rays. Thereby, the ultraviolet-curable component (C) in the adhesive layer 11 is polymerized, and the adhesive layer 11 is cured to become a cured adhesive layer 11 '. Irradiation of the adhesive layer 11 with ultraviolet rays is generally performed over either the first display body constituent member 21 or the second display body constituent member 22, and it is preferably performed over the first display body constituent member 21 as a protective panel. Here, the display body constituent member on the ultraviolet irradiation side (preferably, the first display body constituent member 21 as a protective panel) Even if an ultraviolet absorber is contained, the photopolymerization initiator (D) contained in the adhesive constituting the adhesive layer 11 has an absorbance of 0.3 or more at a wavelength of 380 nm, so it is used to make the photopolymerization initiator (D The ultraviolet rays of the cracked wavelength are not absorbed by the ultraviolet absorber in the display component, so that the photopolymerization initiator (D) is cracked without problems. As a result, the curing reaction of the ultraviolet curable component (C) proceeds well, and the adhesive layer 11 is sufficiently cured. Thereby, the obtained display body 2 becomes a thing which has the excellent level | step difference followability and foam resistance in high temperature and high humidity conditions.

Ultraviolet irradiation can be performed using a high-pressure mercury lamp, a Fusion H lamp, a xenon lamp, and the like. The irradiance of the ultraviolet irradiation amount is preferably about 50 to 1000 mW / cm ² . The light amount is preferably 50 to 10,000 mJ / cm ² , more preferably 80 to 5000 mJ / cm ^{2, and particularly} preferably 200 to 2000 mJ / cm ² .

In the above display body 2, since the hardened adhesive layer 11 'has excellent step-followability even under high temperature and high humidity conditions, the display body 2 is placed under high temperature and high humidity conditions (e.g., 85 ° C, 85%). RH, 72 hours), can also prevent the generation of bubbles, floating, peeling, etc. near the step.

In addition, in the above-mentioned display body 2, since the hardened adhesive layer 11 'has excellent foam resistance, the display body 2 is placed under high temperature and high humidity conditions (for example, 85 ° C, 85% RH, 72 hours), Even when exhaust gas is generated from a display body constituent member made of a plastic plate or the like, it is possible to suppress bubbles, floating, peeling, and the like from occurring at the interface between the cured adhesive layer 11 'and the display body constituent members 21 and 22. .

The embodiments described above are described for easy understanding of the present invention, and are not described to limit the present invention. Therefore, in the above implementation Each element disclosed by the form also includes all design changes and equivalents belonging to the technical scope of the present invention.

For example, any one of the release sheets 12 a and 12 b on the adhesive sheet 1 may be omitted. In addition, the first display body constituent member 21 may be provided with a step other than the printed layer 3 or may not have a step. Furthermore, not only the first display body constituent member 21, but also the second display body constituent member 22 may be a one having a step on the side of the adhesive layer 11 'after curing.

[Example]

Hereinafter, the present invention will be described more specifically with examples and the like, but the scope of the present invention is not limited by these examples and the like.

[Example 1] 1. Preparation of (meth) acrylate copolymer

60 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of isofluorenyl acrylate, 10 parts by mass of N-propenyl morpholine, and 20 parts by mass of 2-hydroxyethyl acrylate were copolymerized to prepare (meth) Acrylate copolymer (A). When the molecular weight of this (meth) acrylate copolymer (A) was measured by the method mentioned later, the weight average molecular weight (Mw) was 500,000.

2. Preparation of adhesive composition

100 parts by mass of the (meth) acrylate copolymer (A) obtained in the above step 1 (solid content conversion value; the same applies hereinafter), and trimethylolpropane-modified toluene diisocyanate as a thermal crosslinking agent (B) 0.2 parts by mass, 5.0 parts by mass of ε-caprolactone-modified ginseng (2-propenyloxyethyl) trimer isocyanate as ultraviolet curing component (C), 2 as photoinitiator (D), 0.5 part by mass of 4,6-trimethylbenzylidene-diphenyl-phosphine oxide and 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent (E) , Product name "KBM-403") 0.3 The parts by mass are mixed and sufficiently stirred, and a coating solution of an adhesive composition having a solid content concentration of 50% by mass is obtained by diluting with methyl ethyl ketone.

3. Manufacture of adhesive sheet

The obtained coating solution of the adhesive composition was applied to a release-treated surface of a heavy release type release sheet (manufactured by LINTEC Corporation, product name "SP-PET752150") using a doctor blade coater, where the heavy release type was peeled The sheet is formed by peeling one side of a polyethylene terephthalate film using a polysiloxane-based release agent. Then, the coating layer was heat-treated at 90 ° C for 1 minute to form a coating layer.

Next, a light release type release sheet (LINTEC) obtained by peeling the coating layer on the obtained heavy release type release sheet and one side of a polyethylene terephthalate film using a polysiloxane-based release agent is used. The product name is "SP-PET382120", manufactured by the company), and the light-peeling type release sheet has a peeling treatment surface that is in contact with the coating layer, and is cured for 7 days at 23 ° C and 50% RH. An adhesive sheet having an adhesive layer having a thickness of 50 μm, that is, an adhesive sheet composed of a heavy release type release sheet / adhesive layer (thickness: 50 μm) / light release type release sheet was manufactured. The thickness of the adhesive layer is a value measured in accordance with JIS K7130 using a constant pressure thickness measuring device (manufactured by Teclock Corporation, product name "PG-02").

Table 1 shows each formulation (solid content conversion value) of the adhesive composition when the (meth) acrylate copolymer (A) is 100 parts by mass (solid content conversion value). The details of the abbreviations and the like described in Table 1 are as follows.

[(Meth) acrylate copolymer (A)]

2EHA: 2-ethylhexyl acrylate

IBXA: isoamyl acrylate

ACMO: N-propenylmorpholine

HEA: 2-hydroxyethyl acrylate

BA: n-butyl acrylate

AA: Acrylic

[Heat crosslinker (B)]

TDI series: Trimethylolpropane modified toluene diisocyanate

Epoxy: 1,3-bis (N, N-glycidylaminomethyl) cyclohexane

[Photopolymerization initiator (D)]

D1: 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide

D2: bis (2,4,6-trimethylbenzyl) -phenylphosphine oxide

D3: the mass ratio of 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide and 2-hydroxy-2-methyl-1-phenylpropane-1-one is 1: 1 Mixed

D4: 1-hydroxycyclohexylphenyl ketone

[Examples 2 to 5, Comparative Examples 1 to 2]

In addition to the types and proportions of the respective monomers constituting the (meth) acrylate copolymer (A), the types and blending amounts of the thermal crosslinking agent (B), the blending amount of the ultraviolet curable component (C), and photopolymerization The type and amount of the initiator (D) were changed in the same manner as in Example 1 except for the changes shown in Table 1, to produce an adhesive sheet.

Here, the aforementioned weight average molecular weight (Mw) refers to a weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement conditions>

‧GPC measuring device: manufactured by TOSOH, HLC-8020

‧GPC column (passed in the following order): made by TOSOH

TSK guard column HXL-H

TSK gel GMHXL (× 2)

TSK gel G2000HXL

‧Determination solvent: tetrahydrofuran

‧Measuring temperature: 40 ℃

[Test Example 1] (Measurement of absorbance)

An acetonitrile solution having a concentration of 0.1% by mass of the photopolymerization initiator used in the examples and comparative examples was prepared, and the absorbance of the solution in a wavelength range of 200 to 500 nm was used (manufactured by Shimadzu Corporation, product name "UV-3600") And the determination. Based on the results, the absorption maximum wavelength (nm) of the absorbance at a wavelength of 380 nm and the absorbance at a wavelength of 200 to 500 nm was derived. The results are shown in Table 1.

[Test Example 2] (Measurement of gel fraction)

The adhesive sheets obtained in the examples and comparative examples were cut into a size of 80 mm × 80 mm, the adhesive layer was wrapped in a polyester mesh (mesh size 200), and the mass was measured using a precision balance. The mass of only the adhesive is calculated by subtracting the mass of the mesh alone. Let the mass at this time be M1.

Next, the adhesive covered with the polyester mesh was immersed in ethyl acetate at room temperature (23 ° C) for 72 hours. Subsequently, the adhesive was taken out and air-dried in an environment at a temperature of 23 ° C. and a relative humidity of 50% for 24 hours, and then dried in an oven at 80 ° C. for 12 hours. After drying, weigh the mass using a precision balance, and subtract the mass of the mesh alone to calculate the mass of only the adhesive. The mass at this time is set to M2. The gel fraction (%) is expressed as (M2 / M1) × 100. Thereby, the gel fraction of the adhesive (before ultraviolet irradiation) was derived. The results are shown in Table 2.

On the other hand, the lightly peelable release sheet was peeled from the adhesive sheet obtained in Examples and Comparative Examples, and the exposed adhesive layer was directly irradiated with ultraviolet rays under the following conditions to harden the adhesive layer to become cured adhesive.剂 层。 The agent layer. The gel fraction (after ultraviolet irradiation; direct irradiation) was derived for the adhesive of the cured adhesive layer in the same manner as described above. The results are shown in Table 2.

In addition, the lightly peelable release sheet was peeled from the adhesive sheet obtained in the examples and comparative examples, and the exposed adhesive layer was bonded to a resin sheet having a polymethyl methacrylate layer and a polycarbonate layer (Mitsubishi The surface of the side of the polycarbonate layer manufactured by Gas Chemical Co., Ltd. with the product name "UPILON‧SHEET MR-58U", thickness: 0.8 mm, and containing an ultraviolet absorber). Next, the adhesive layer is irradiated with ultraviolet rays over the resin plate under the following conditions to harden the adhesive layer to become a cured adhesive layer. The gel fraction (after ultraviolet irradiation; irradiation over a resin plate) of the adhesive of the cured adhesive layer was performed in the same manner as described above. In addition, a value obtained by subtracting the gel fraction after the ultraviolet rays irradiated across the resin plate from the gel fraction after the ultraviolet rays directly irradiated was calculated. Show the results in Table 2

<UV irradiation conditions>

‧Use high pressure mercury lamp

‧Illumination 200mW / cm ² , 2000mJ / cm ²

‧UV Illumination‧Light meter uses "UVPF-A1" manufactured by EYEGRAPHICS

[Test Example 3]

(Evaluation of foam resistance)

The adhesive sheet adhesive layers obtained in the examples and comparative examples were used in one A transparent conductive film of polyethylene terephthalate film (manufactured by Oike Industry Co., Ltd., ITO film, thickness: 125 μm), and a transparent polyimide film made of indium tin oxide (ITO) A resin plate of a methyl acrylate layer and a polycarbonate layer (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name "UPILON‧SHEET MR-58U", thickness: 0.8 mm, containing ultraviolet absorber) is sandwiched between the surfaces of the polycarbonate layer side . Subsequently, the autoclave treatment was performed under the conditions of 50 ° C and 0.5 MPa for 30 minutes, and left at normal pressure, 23 ° C and 50% RH for 24 hours.

The adhesive layer of the obtained laminated body was irradiated with ultraviolet rays over the resin plate under the same conditions as in Test Example 2 to harden the adhesive layer to become a cured adhesive layer. Next, it was stored for 72 hours under high temperature and high humidity conditions of 85 ° C and 85% RH. Subsequently, the state of the interface between the adhesive layer and the adherend after curing was visually confirmed, and the foam resistance was evaluated in accordance with the following criteria. The results are shown in Table 2.

○ ... No bubbles and no floating

× ... bubbles, traces of bubbles, or floating

[Experimental Example 4] (Measurement of Step Following Rate 1)

On the surface of a glass plate (manufactured by NSG PRECISION, product name "Corning glass EAGLE XG", 90 mm in length x 50 mm in width x 0.5 mm in thickness), a UV-curable ink (manufactured by Imperial Ink Corporation, product name "POS-911 Ink" ), And screen printing was performed in a frame shape so that the coating thickness became any of 25 μm, 30 μm, and 40 μm (outer shape: 90 mm in length × 50 mm in width and 5 mm in width). Next, ultraviolet light (80 W / cm ² , metal halide lamp 2 lamp, lamp height 15 cm, conveyor belt speed 10 to 15 m / min) is irradiated to harden the ultraviolet curing ink after printing to produce a step (step difference) by printing. Height: any of 25 μm, 30 μm, and 40 μm) with a stepped glass plate.

The lightly peelable release sheet was peeled from the adhesive sheet obtained in Examples and Comparative Examples, and the exposed adhesive layer was bonded to a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., Product name "PET A4300", thickness: 100 μm). Next, peel off the heavy release-type release sheet to expose the surface of the adhesive layer, and use a laminating machine (manufactured by Fujipla, product name "LPD3214") to apply the adhesive layer as a frame-shaped printing on the entire surface of the adhesive. The stepped glass plates fit. Subsequently, an autoclave treatment was performed under the conditions of 50 ° C. and 0.5 MPa for 30 minutes and left at normal pressure, 23 ° C., and 50% RH for 24 hours.

The adhesive layer of the obtained laminated body was irradiated with ultraviolet rays under the same conditions as in Test Example 2 over the polyethylene terephthalate film to harden the adhesive layer to become a cured adhesive layer. Next, it was stored for 72 hours (durability test) under high-temperature and high-humidity conditions of 85 ° C and 85% RH, and then the step followability was evaluated. The step followability is judged by whether the printed step difference is completely buried in the adhesive layer after hardening. When bubbles, floating, peeling, etc. are observed at the interface between the printed step difference and the cured adhesive layer, it can be judged that it cannot follow the printing. Segment difference. Here, the step-following property is evaluated as a step-following ratio (%) represented by the following formula. The results are shown in Table 2. In addition, a case where the step following rate of 50% cannot be satisfied is described as ×.

Step-following rate (%) = ((height of step difference (μm) capable of maintaining landfill without bubbles, floating, peeling, etc. after endurance test)) / (thickness of adhesive layer: 50 μm)} × 100

[Test Example 5]

(Measurement of step following rate 2)

In the same manner as in Test Example 4, a laminated body obtained by holding the pressure-sensitive adhesive sheet sheet obtained in the examples and comparative examples using the glass plate with the step difference and the polyethylene terephthalate film was obtained. A polymethyl methacrylate layer will be provided on the polyethylene terephthalate film of the obtained laminated body (after the autoclave treatment, and left at normal pressure, 23 ° C., and 50% RH for 24 hours). And polycarbonate resin sheet (manufactured by Mitsubishi GAS Chemical Co., Ltd., product name "UPILON‧SHEET MR-58U", thickness: 0.8 mm, containing ultraviolet absorber), the surface of the polycarbonate layer side with the above polyparaphenylene The ethylene diformate film is arranged in a surface contact manner. Then, the adhesive layer was irradiated with ultraviolet rays under the same conditions as in Test Example 2 over the resin plate and the polyethylene terephthalate film to harden the adhesive layer to become a cured adhesive layer. Subsequently, the resin plate was removed and subjected to the same durability test and evaluation as in Test Example 4. The results are shown in Table 2.

[Test Example 6] (Evaluation of light resistance)

Using the adhesive sheet obtained in the Example, it carried out similarly to the test example 3, and produced the laminated body. The adhesive layer of the obtained laminate was irradiated with ultraviolet rays under the same conditions as in Test Example 2 over the resin plate, and the adhesive layer was cured to become a cured adhesive layer. Subsequently, it was put into a light resistance tester (manufactured by SUGA Tester Co., Ltd., product name "UV Fade Meter U48", light source: carbon arc lamp), and ultraviolet rays (illumination: 50 mW / cm ² ) were irradiated from the resin plate side for 100 hours. Subsequently, when the state of the transparent conductive film of the laminated body was visually confirmed, no change was observed in the transparent conductive film.

On the other hand, except that the adhesive sheet of Comparative Example 2 was used, and the resin sheet was changed to a polycarbonate resin sheet (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name "HMRS51T") that does not contain an ultraviolet absorber, it corresponds to Test Example 3 A laminated body was produced in the same manner. The adhesive layer of the obtained laminated body was passed through the resin plate and irradiated with ultraviolet rays under the same conditions as in Test Example 2 to cure the adhesive layer to become a cured adhesive layer. Subsequently, it was put into a light resistance tester (manufactured by SUGA Tester Co., Ltd., product name "UV Fade Meter U48", light source: carbon arc lamp), and ultraviolet rays (illumination intensity: 50 mW / cm ² ) were irradiated from the resin plate side for 100 hours. Subsequently, when the state of the transparent conductive film of the laminated body was visually confirmed, discoloration was observed in the transparent conductive film.

As can be seen from Table 2, even when the adhesive layer obtained in the example is irradiated with ultraviolet rays over a resin plate containing an ultraviolet absorber, as a cured adhesive layer, it has a step-following follow-up property and resistance to high temperature and humidity. Both foaming properties are excellent.

Industrial availability

The adhesive sheet of the present invention can be suitably used in, for example, a protective panel having a step and containing an ultraviolet absorber, and bonding to a required display constituent member.

1‧‧‧ Adhesive sheet

11‧‧‧ Adhesive layer

12a, 12b ‧‧‧ peeling sheet

Claims (9)

An adhesive plate is provided with an adhesive plate which is an adhesive layer for bonding a display component to other display components, and is characterized in that the adhesive layer is made of (meth) acrylic acid. The ester copolymer (A) and the thermal cross-linking agent (B) have a cross-linked structure, and the absorbance at a wavelength of 380 nm in the acetonitrile solution containing the ultraviolet-curable component (C) and the concentration of 0.1% by mass is 0.3 or more. The photopolymerization initiator (D) is an ultraviolet curable adhesive. The adhesive sheet according to item 1 of the scope of patent application, wherein the gel fraction of the adhesive is 30% or more and 70% or less. According to the adhesive sheet described in item 1 of the scope of patent application, at least one of the one display component and the other display component includes an ultraviolet absorbent. The adhesive sheet according to item 1 of the scope of the patent application, wherein the display body constituent member has a step at least on a surface to be bonded. The adhesive sheet according to item 1 of the scope of the patent application, wherein the adhesive sheet is provided with two release sheets, and the adhesive layer is held by the release sheet in a manner of contacting the release surface of the two release sheets. . A method for manufacturing an adhesive plate is provided with a method for manufacturing an adhesive plate that is an adhesive layer for bonding a display component to other display components, and is characterized in that: (Meth) acrylate copolymer (A), thermal cross-linking agent (B), The ultraviolet curable component (C) and the adhesive composition of the photopolymerization initiator (D) having an absorbance of 0.3 or more at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass are applied and thermally crosslinked to form ultraviolet rays. Hardening adhesive layer. A display body is a display body comprising a display body constituent member, other display body constituent members, and a cured adhesive layer after bonding the display body constituent member and the other display body constituent member to each other, which is characterized in that: : This hardened adhesive layer has a crosslinked structure composed of a (meth) acrylate copolymer (A) and a thermal crosslinker (B), and is a cured product containing an ultraviolet curable component (C). And a photopolymerization initiator (D) having an absorbance of 0.3 or more in an acetonitrile solution having a concentration of 0.1% by mass and a wavelength of 380 nm, which is an adhesive. A display body is a display body comprising a display body constituent member, other display body constituent members, and a cured adhesive layer after bonding the display body constituent member and the other display body constituent member to each other, which is characterized in that: : The hardened adhesive layer has a crosslinked structure composed of a (meth) acrylate copolymer (A) and a thermal crosslinker (B), and is a cured product containing an ultraviolet curable component (C). It is composed of an adhesive, and the gel fraction of the cured adhesive layer is 40% to 95%. A method for manufacturing a display body is characterized by: A laminated body formed by laminating an adhesive layer of one of the adhesive plates according to any one of items 1 to 5 by laminating a display component and other display components, and manufacturing the laminate The adhesive layer is irradiated with ultraviolet rays to make the adhesive layer become a cured adhesive layer.