JP6744850B2 - STRUCTURE AND ITS MANUFACTURING METHOD, DISPLAY, AND OPTICAL ADHESIVE SHEET - Google Patents

Description

The present invention relates to a display body (display), a structure used for the display body, a manufacturing method thereof, and an optical pressure-sensitive adhesive sheet used for manufacturing them.

In recent years, car navigation systems are often mounted on automobiles. In the display body (display) of the car navigation system, a protective panel is provided on the front surface side of the display body module. Usually, the protective panel is adhered to the display module or the like via the adhesive layer.

As a protection panel for a car navigation system, a plastic plate is often used instead of a glass plate mainly from the viewpoint of safety. However, unlike a glass plate, a plastic plate generates outgas and transmits water vapor under high temperature and high humidity (wet heat) conditions. Thereby, blisters such as air bubbles, floating, and peeling may occur between the plastic plate and the adhesive layer.

In order to suppress the occurrence of such blister, it is considered to increase the cohesive force of the pressure-sensitive adhesive. Patent Document 1 includes a (meth)acrylic copolymer of a monomer containing a (meth)acrylic acid ester having an ultraviolet-crosslinkable site (benzophenone structure), and ultraviolet-crosslinking in which the storage elastic modulus before and after ultraviolet-ray crosslinking is defined. Dispersible pressure sensitive adhesive sheet is disclosed. Such an ultraviolet-crosslinkable pressure-sensitive adhesive sheet is for adhering an adherend and then irradiating it with ultraviolet rays to promote a crosslinking reaction to increase cohesive force.

JP, 2011-184582, A

However, in the above-mentioned UV-crosslinkable pressure-sensitive adhesive sheet, the UV-crosslinkable pressure-sensitive adhesive may not be sufficiently cured depending on the type of the protection panel, and blisters may occur under high temperature and high humidity conditions.

In addition, in the display body as described above, the member to which the plastic plate as the protective panel is attached is usually a glass plate or a member having a linear expansion coefficient equivalent to that of the glass plate. In such a display body, warpage may occur when placed under high temperature conditions due to the difference in linear expansion coefficient between the two members that are bonded together.

The present invention has been made in view of the above-mentioned actual circumstances, a display body having excellent blistering resistance and suppressing the occurrence of warp, a structure used for the display body and a method for manufacturing the same, and those. It is an object to provide an optical pressure-sensitive adhesive sheet that can be manufactured.

In order to achieve the above-mentioned object, firstly, according to the present invention, one display member constituting member, another display member constituting member, the one display member constituting member and the other display member constituting member are attached to each other. And a pressure-sensitive adhesive layer to be combined, wherein at least one of the one display member constituting member and the other display member constituting member is an ultraviolet shielding member having an ultraviolet shielding property, The display body constituent member and the other display body constituent member are made of materials having different linear expansion coefficients from each other, and are 10% by torsion shear according to JIS K7244-1 for the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer. The relaxation elastic modulus measured 10 minutes after the strain application is 0.1 kPa or more and 15 kPa or less, and the gel fraction of the pressure-sensitive adhesive is 60% or more and 90% or less. (Invention 1).

By satisfying the above physical properties, the structure according to the above invention (Invention 1) is suppressed in warpage and is also excellent in blister resistance.

In the said invention (invention 1), it is preferable that the said pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer after hardening formed by irradiation with active energy rays (invention 2).

In the above inventions (Inventions 1 and 2), the ultraviolet ray shielding member has a light transmittance of 20% or less at a wavelength of 360 nm, a light transmittance of 10% or more at a wavelength of 390 nm, and a light transmittance of 390 nm. Is preferably higher than the light transmittance at a wavelength of 360 nm (Invention 3).

In the above inventions (Inventions 1 to 3), one of the one display member forming member and the other display member forming member is a plastic plate, and the one display member forming member and the other display member forming member. The other is preferably a glass plate or a member having a linear expansion coefficient equivalent to that of the glass plate (Invention 4).

Secondly, the present invention provides a display body characterized by including the above-mentioned structure (Inventions 1 to 4) (Invention 5).

Thirdly, the present invention is an optical pressure-sensitive adhesive sheet having an active energy ray-curable pressure-sensitive adhesive layer made of an active energy ray-curable pressure-sensitive adhesive, wherein the active energy ray-curable pressure-sensitive adhesive constitutes a polymer. As the monomer, a (meth)acrylic acid ester polymer (A) containing 1% by mass or more and 25% by mass or less of a monomer having a hydroxyl group in the molecule, a crosslinking agent (B), and an active energy ray-curable component (C). And a photopolymerization initiator (D) having an absorbance of 0.3 or more at a wavelength of 390 nm in an acetonitrile solution having a concentration of 0.1% by mass, the (meth)acrylic ester. It contains a crosslinked structure in which the polymer (A) is crosslinked with each other through the crosslinking agent (B), the unreacted active energy ray-curable component (C) and the photopolymerization initiator (D). The invention provides an optical pressure-sensitive adhesive sheet, characterized in that the gel fraction of the active energy ray-curable pressure-sensitive adhesive increases with curing by irradiation with active energy rays by 5 points or more (Invention 6).

By using the optical pressure-sensitive adhesive sheet according to the above invention (Invention 6), it is possible to manufacture a structural body that suppresses warpage and is also excellent in blister resistance, and thus a display body.

In the above invention (Invention 6), the content of the active energy ray-curable component (C) in the adhesive composition is 100 parts by mass of the (meth)acrylic acid ester polymer (A). It is preferably 2 parts by mass or more and 20 parts by mass or less (Invention 7).

In the above inventions (Inventions 6 and 7), the gel fraction of the active energy ray-curable pressure-sensitive adhesive is preferably 30% or more and 70% or less (Invention 8).

In the above inventions (Inventions 6 to 8), two release sheets and the active energy ray-curable pressure-sensitive adhesive layer sandwiched between the release sheets so as to contact the release surfaces of the two release sheets. It is preferable to provide (Invention 9).

Fourthly, the present invention relates to one display member constituting member, at least one of which is the ultraviolet shielding member, via the active energy ray-curable pressure-sensitive adhesive layer of the optical pressure-sensitive adhesive sheet (Invention 6 to 9), and the like. Of the display body constituting member is produced, and the adhesive layer of the laminate is irradiated with an active energy ray through the ultraviolet shielding member to cure the adhesive layer. There is provided a method for producing a structure, which is characterized in that it is used as a pressure-sensitive adhesive layer after curing (Invention 10).

The display body and the structural body according to the present invention have excellent blister resistance and suppress the occurrence of warpage. Further, according to the optical pressure-sensitive adhesive sheet of the present invention, the blister resistance is excellent and the occurrence of warpage can be suppressed.

It is sectional drawing of the adhesive sheet for optics which concerns on one Embodiment of this invention. It is sectional drawing of the display body which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
[Optical pressure-sensitive adhesive sheet]
An optical pressure-sensitive adhesive sheet according to an embodiment of the present invention is an optical pressure-sensitive adhesive sheet having an active energy ray-curable pressure-sensitive adhesive layer made of an active energy ray-curable pressure-sensitive adhesive. The optical pressure-sensitive adhesive sheet according to the present embodiment preferably comprises a release sheet laminated on one side or both sides of the active energy ray-curable pressure-sensitive adhesive layer.

The optical pressure-sensitive adhesive sheet according to the present embodiment is preferably used for laminating one display member constituting member and another display member constituting member, and particularly, one display member constituting member and the other display member. It is preferably used when at least one of the constituent members is an ultraviolet-shielding member having an ultraviolet-shielding property, and further, one display body constituent member and another display body constituent member are made of materials having different linear expansion coefficients from each other. It is preferably used in some cases. However, the optical pressure-sensitive adhesive sheet according to the present embodiment is not limited to these applications, and can be used for bonding various optical members.

Here, the ultraviolet ray blocking member according to the present embodiment has a light transmittance of 20% or less at a wavelength of 360 nm, a light transmittance of 10% or more at a wavelength of 390 nm, and a light transmittance of 390 nm is 360 nm. Is larger than the light transmittance of. The display and the display member will be described later.

Further, the active energy ray in the present embodiment preferably emits light with substantial intensity in a wavelength region exceeding a wavelength of 365 nm. The wavelength range is preferably 380 to 450 nm, more preferably 390 to 410 nm. Further, when the maximum emission intensity at 365 nm or less (usually, the maximum peak intensity near 365 nm) is 100%, the intensity is 20% or more in at least a part of the above wavelength region. It is preferable.

A specific configuration as an example of the optical pressure-sensitive adhesive sheet according to the present embodiment is shown in FIG.
As shown in FIG. 1, an optical pressure-sensitive adhesive sheet 1 according to an embodiment includes two release sheets 12a and 12b and two release sheets 12a and 12b that are in contact with release surfaces of the two release sheets 12a and 12b. The active energy ray-curable pressure-sensitive adhesive layer 11 is sandwiched between the sheets 12a and 12b. In addition, the release surface of the release sheet in the present specification refers to a surface having releasability in the release sheet, and includes both a surface subjected to a release treatment and a surface exhibiting releasability without performing the release treatment. ..

1. Each member 1-1. Energy ray-curable pressure-sensitive adhesive layer The active energy ray-curable pressure-sensitive adhesive constituting the active energy ray-curable pressure-sensitive adhesive layer 11 is a monomer having a hydroxyl group in the molecule (a hydroxyl group-containing monomer) as a monomer constituting the polymer. (Meth)acrylic acid ester polymer (A) containing 1% by mass or more and 25% by mass or less, a crosslinking agent (B), an active energy ray-curable component (C), and a concentration of 0.1% by mass. Obtained from an adhesive composition containing a photopolymerization initiator (D) having an absorbance at a wavelength of 390 nm of 0.3 or more in an acetonitrile solution (hereinafter sometimes referred to as “adhesive composition P”), ( A crosslinked structure in which the (meth)acrylic acid ester polymer (A) is crosslinked with each other via a crosslinking agent (B), an unreacted active energy ray-curable component (C) and a photopolymerization initiator (D). It is contained, and the increase in the gel fraction of the above-mentioned active energy ray-curable pressure-sensitive adhesive due to curing by irradiation with active energy ray is 5 points or more. That is, the active energy ray-curable pressure-sensitive adhesive is obtained by crosslinking (thermally crosslinking) the pressure-sensitive adhesive composition P, and contains the unreacted active energy ray-curable component (C) and the photopolymerization initiator (D). ), it has active energy ray curability. In addition, in this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, the concept of “copolymer” is also included in “polymer”.

Next, a preferred usage example of the optical pressure-sensitive adhesive sheet 1 according to the present embodiment will be described. One display body constituent member and another display body constituent member are bonded together by the active energy ray-curable pressure sensitive adhesive layer 11 of the optical pressure-sensitive adhesive sheet 1. At least one of the one display member forming member and the other display member forming member is an ultraviolet shielding member. Then, the adhesive layer 11 is irradiated with active energy rays through the display member constituting member which is the ultraviolet ray shielding member to cure the adhesive layer 11 to cure the adhesive layer (in FIG. After curing, the pressure-sensitive adhesive layer 11′) is used. The “after curing” of the pressure-sensitive adhesive layer after curing means a state in which the increase in the gel fraction of the pressure-sensitive adhesive due to irradiation with active energy rays is less than 5 points.

The active energy ray-curable pressure-sensitive adhesive obtained by crosslinking (thermally crosslinking) the pressure-sensitive adhesive composition P is relatively soft in the stage before curing by irradiation with active energy rays. Therefore, when the optical pressure-sensitive adhesive sheet 1 is attached to a display member having a step, the pressure-sensitive adhesive layer 11 easily follows the step, and it is possible to prevent gaps, floats, and the like from occurring near the step. That is, the pressure-sensitive adhesive layer 11 has excellent initial step followability. Further, the active energy ray-curable pressure-sensitive adhesive that constitutes the pressure-sensitive adhesive layer 11 is cross-linked and has a certain degree of cross-linking density and a predetermined cohesive force, so that the pressure-sensitive adhesive layer 11 has a relatively high coating strength. Therefore, for example, it is possible to prevent the adhesive from adhering to the blade when cutting the optical pressure-sensitive adhesive sheet 1 or the like, and to prevent the adhesive from seeping out from the adhesive layer 11 during storage.

Here, when a conventional photopolymerization initiator, for example, 1-hydroxycyclohexyl phenyl ketone, is used for the pressure-sensitive adhesive and the active energy ray is irradiated to the pressure-sensitive adhesive layer through the ultraviolet shielding member, the above photopolymerization initiator Of the active energy ray having a wavelength (near 340 nm) for cleaving the photopolymerization initiator is blocked by the UV-shielding member, and the cleavage of the photopolymerization initiator is inhibited. As a result, the curing reaction of the active energy ray-curable component does not proceed well, and the curing of the pressure-sensitive adhesive layer becomes insufficient. Then, the blister resistance deteriorates, and blisters are likely to occur at the interface between the display member and the cured pressure-sensitive adhesive layer.

On the other hand, the active energy ray-curable pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 11 in the optical pressure-sensitive adhesive sheet 1 according to the present embodiment has an absorbance of 0.3 or more at a wavelength of 390 nm in an acetonitrile solution having a concentration of 0.1% by mass. The photopolymerization initiator (D) is In this case, even if the adhesive layer 11 is irradiated with an active energy ray through the ultraviolet shielding member, an active energy ray having a wavelength (near 390 nm) for cleaving the photopolymerization initiator is applied to the ultraviolet shielding member. It is not shielded and the photopolymerization initiator (D) is cleaved without any problem. As a result, the curing reaction of the active energy ray-curable pressure-sensitive adhesive (specifically, the active energy ray-curable component (C)) proceeds well, the pressure-sensitive adhesive layer 11 is sufficiently cured, and the obtained cured pressure-sensitive adhesive is obtained. The cohesive force of the agent layer is improved. Thereby, a structure provided with one display member forming member (ultraviolet ray shielding member), another display member forming member, and a cured adhesive layer for bonding them together, particularly one display member forming member (Ultraviolet shielding member) is a plastic plate that generates outgas under high temperature and high humidity conditions and permeates water vapor, and is subjected to high temperature and high humidity conditions, for example, 85° C. and 85% RH conditions for 72 hours. Even when placed, the occurrence of blisters such as bubbles, floating, and peeling at the interface between the display member and the cured pressure-sensitive adhesive layer is suppressed.

(1) Component (1-1) (meth)acrylic acid ester polymer (A)
The (meth)acrylic acid ester polymer (A) contains 1% by mass or more and 25% by mass or less of a hydroxyl group-containing monomer as a monomer constituting the polymer. Since the content of the hydroxyl group-containing monomer is relatively small as described above, the crosslinking density of the obtained pressure-sensitive adhesive can be made relatively small and the elastic modulus can be made low. As a result, one display member constituting member and another display member constituting member having different linear expansion coefficients (for example, a plastic plate and a glass plate or a member having a linear expansion coefficient equivalent to that of a glass plate) are bonded together. Even when the composition provided with the post-curing pressure-sensitive adhesive layer is left under high temperature conditions, for example, 105° C. and drying conditions for 72 hours, after the curing, the deviation due to the difference in shrinkage ratio between the two display member components is cured. It can be mitigated by the pressure-sensitive adhesive layer, and thus the warp of the structural body can be suppressed.

When the content of the hydroxyl group-containing monomer exceeds 25% by mass, the crosslink density of the obtained pressure-sensitive adhesive increases, and the relaxation elastic modulus of the cured pressure-sensitive adhesive forming the cured pressure-sensitive adhesive layer increases. This makes it difficult to obtain the above-described warp suppressing effect. On the other hand, when the content of the hydroxyl group-containing monomer is less than 1% by mass, the cohesive force of the obtained pressure-sensitive adhesive becomes too low, and the gel fraction of the pressure-sensitive adhesive after curing becomes too low. As a result, the blister resistance is deteriorated.

From the above viewpoint, the upper limit of the content of the hydroxyl group-containing monomer as a constituent monomer in the (meth)acrylic acid ester polymer (A) is preferably 20% by mass or less, and particularly 15% by mass or less. It is preferable that the content is 9% by mass or less. The lower limit of the content of the hydroxyl group-containing monomer is preferably 2% by mass or more, and particularly preferably 4% by mass or more.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and (meth ) Hydroxyalkyl esters of (meth)acrylic acid such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth)acrylate. Among them, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferable, and 2-hydroxyethyl (meth)acrylate is particularly preferable, from the viewpoint of blister resistance. These may be used alone or in combination of two or more.

In view of the above mechanism of action, the (meth)acrylic acid ester polymer (A) is a reactive functional group having a reactive functional group in the molecule, other than a hydroxyl group-containing monomer, as a monomer constituting the polymer. It is preferable not to include a contained monomer, for example, a carboxyl group-containing monomer or an amino group-containing monomer.

The (meth)acrylic acid ester polymer (A) preferably contains a (meth)acrylic acid alkyl ester as a monomer unit constituting the polymer. Thereby, good adhesiveness can be exhibited. The alkyl group may be linear or branched.

As the (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferable from the viewpoint of adhesiveness. Examples of the (meth)acrylic acid alkyl ester whose alkyl group has 1 to 20 carbon atoms include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and (meth)acrylic acid n-. Butyl, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, (meth)acrylic acid Examples thereof include n-dodecyl, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate.

Among the above, (meth)acrylic acid alkyl ester having 2 to 12 carbon atoms in the alkyl group is more preferable, and the alkyl group having 2 to 12 carbon atoms is more preferable, from the viewpoint of efficiently imparting the adhesive force and setting the relaxation elastic modulus to a desired range. Particularly preferred are alkyl acrylates having 5 to 10 carbon atoms. Specifically, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate and isooctyl (meth)acrylate are preferred, and 2-ethylhexyl acrylate and isooctyl acrylate are more preferred. These may be used alone or in combination of two or more.

From the viewpoint of imparting tackiness, the (meth)acrylic acid ester polymer (A) has 40 (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer. It is preferably contained in an amount of 50% by mass, more preferably 50% by mass or more, and particularly preferably 60% by mass. Further, from the viewpoint of ensuring the blending amount of other components, it is preferable that the (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is 94% by mass or less, and 85% by mass or less is contained. It is more preferable that the content is 80% by mass or less.

The (meth)acrylic acid ester polymer (A) preferably contains a monomer having an alicyclic structure (alicyclic structure-containing monomer) as a monomer unit constituting the polymer. By containing the alicyclic structure-containing monomer, the bulky functional group makes it possible to widen the distance between the (meth)acrylic acid ester polymers (A), and to easily reduce the relaxation elastic modulus of the resulting cured adhesive. ..

The carbon ring having an alicyclic structure may have a saturated structure or may have an unsaturated bond. Further, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as a bicyclic ring or a tricyclic ring. The alicyclic structure preferably has 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and further preferably 7 to 12 carbon atoms.

Examples of the alicyclic structure include cyclohexyl skeleton, dicyclopentadiene skeleton, adamantane skeleton, isobornyl skeleton, cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononane skeleton, cyclodecane skeleton, cycloundecane skeleton, etc.) Preferred examples include those having a cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, polycyclic skeleton (cuban skeleton, basket skeleton, hausan skeleton, etc.), and spiro skeleton. Among them, those containing an adamantane skeleton and an isobornyl skeleton are preferable from the viewpoint of further improving the blister resistance in addition to the reduction of the relaxation elastic modulus.

The alicyclic structure-containing monomer is preferably a (meth)acrylic acid ester monomer containing the above skeleton, and specifically, (meth)acrylic acid cyclohexyl, (meth)acrylic acid dicyclopentanyl, (meth) Examples thereof include adamantyl acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. Among them, adamantyl (meth)acrylate and isobornyl (meth)acrylate. Is preferred. These may be used alone or in combination of two or more.

The (meth)acrylic acid ester polymer (A) contains an alicyclic structure-containing monomer in an amount of 3% by mass or more as a monomer unit constituting the polymer, from the viewpoint of reducing the relaxation elastic modulus of the obtained pressure-sensitive adhesive after curing. It is preferably contained, more preferably 6% by mass or more, and particularly preferably 9% by mass or more.

In addition, the content of the alicyclic structure-containing monomer in the (meth)acrylic acid ester polymer (A) is preferably 30% by mass or less, and 20% by mass, from the viewpoint of ensuring the blending amount of other components. It is more preferable to set the content to the following, and it is particularly preferable to set it to 15% by mass or less.

Moreover, it is preferable that the (meth)acrylic acid ester polymer (A) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer. Examples of the nitrogen atom-containing monomer include a monomer having an amino group, a monomer having an amide group, a monomer having a nitrogen-containing heterocycle, and the like. Among them, a monomer having a nitrogen-containing heterocycle is preferable.

Examples of the monomer having a nitrogen-containing heterocycle include N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloyl. Pyrrolidine, N-(meth)acryloylaziridine, aziridinylethyl(meth)acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide, etc. Among them, N-(meth)acryloylmorpholine, which exhibits more excellent adhesive strength, is preferable, and N-acryloylmorpholine is particularly preferable.

As the nitrogen atom-containing monomer, for example, (meth)acrylamide, N-methyl(meth)acrylamide, N-methylol(meth)acrylamide, N-tert-butyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide. , N,N-ethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-phenyl(meth)acrylamide, dimethylaminopropyl(meth)acrylamide, N-vinyl Caprolactam, monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, monoethylaminopropyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, etc. It can also be used.
The above nitrogen atom-containing monomers may be used alone or in combination of two or more.

The (meth)acrylic acid ester polymer (A) contains 2% by mass or more of a nitrogen atom-containing monomer as a monomer unit constituting the polymer from the viewpoint of improving adhesion to an adherend such as glass. It is preferable that the content is 4% by mass, more preferably 8% by mass or more. Further, the content of the nitrogen atom-containing monomer is preferably 30% by mass or less, more preferably 20% by mass or less, and 15% by mass or less from the viewpoint of ensuring the blending amount of the other components. Is particularly preferable.

The (meth)acrylic acid ester polymer (A) is preferably a solution polymerized product obtained by a solution polymerization method. Since it is a solution polymer, a high-molecular weight polymer can be easily obtained, and a pressure-sensitive adhesive excellent in blister resistance can be obtained.

The polymerization mode of the (meth)acrylic acid ester polymer (A) may be a random copolymer or a block copolymer.

The lower limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is preferably 200,000 or more, particularly preferably 300,000 or more, and further preferably 400,000 or more. When the lower limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is at least the above, the resulting adhesive will have more excellent blister resistance.

The weight average molecular weight of the (meth)acrylic acid ester polymer (A) is preferably 2,000,000 or less as an upper limit, particularly preferably 1.5,000,000 or less, and further preferably 1,000,000 or less. preferable. When the upper limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is at most the above value, the resulting pressure-sensitive adhesive will have better step followability. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

In the pressure-sensitive adhesive composition P, the (meth)acrylic acid ester polymer (A) may be used alone or in combination of two or more.

The content of the (meth)acrylic acid ester polymer (A) in the pressure-sensitive adhesive composition P according to this embodiment is preferably 85% by mass or more, and particularly preferably 87% by mass or more, as a lower limit value. Is preferable, and more preferably 90% by mass or more. When the lower limit of the content of the (meth)acrylic acid ester polymer (A) is the above, the resulting adhesive has more excellent warp suppressing effect. The upper limit of the content of the (meth)acrylic acid ester polymer (A) is preferably 98% by mass or less, more preferably 97% by mass or less, and particularly 96% by mass or less. It is preferable that the content is 95% by mass or less. Since the upper limit of the content of the (meth)acrylic acid ester polymer (A) is as described above, other contents such as the cross-linking agent (B), the active energy ray-curable component (C) and the photopolymerization initiator (D) can be obtained. The content of the components is secured, and the blister resistance becomes more excellent.

(1-2) Crosslinking agent (B)
The cross-linking agent (B) can cross-link the (meth)acrylic acid ester polymer (A) by heating the pressure-sensitive adhesive composition P and form a good three-dimensional network structure. Thereby, an adhesive having a predetermined cohesive force can be obtained, and excellent blister resistance can be achieved.

As the crosslinking agent (B), for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, an amine crosslinking agent, a melamine crosslinking agent, an aziridine crosslinking agent, a hydrazine crosslinking agent, an aldehyde crosslinking agent, an oxazoline crosslinking agent, Examples thereof include metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, ammonium salt-based crosslinking agents, and the like. The crosslinking agent (B) may be used alone or in combination of two or more.

Here, the (meth)acrylic acid ester polymer (A) in the adhesive composition P contains a hydroxyl group-containing monomer as a monomer constituting the polymer. Therefore, as the cross-linking agent (B), it is preferable to use an isocyanate cross-linking agent having excellent reactivity with the hydroxyl group derived from the hydroxyl group-containing monomer.

The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, aromatic polyisocyanates such as xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate. And their biurets, isocyanurates, and adducts which are reaction products with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane and castor oil. Among them, trimethylolpropane-modified aromatic polyisocyanate, particularly trimethylolpropane-modified tolylene diisocyanate and trimethylolpropane-modified xylylene diisocyanate are preferable from the viewpoint of reactivity with a hydroxyl group.

The content of the cross-linking agent (B) in the adhesive composition P is preferably 0.01 part by mass or more as a lower limit value with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A). In particular, the amount is preferably 0.05 part by mass or more, and more preferably 0.1 part by mass or more. When the lower limit of the content of the cross-linking agent (B) is the above, a predetermined cross-linked structure is formed, and the resulting pressure-sensitive adhesive has more excellent blister resistance. The upper limit of the content is preferably 1.0 part by mass or less, particularly preferably 0.8 part by mass or less, and further preferably 0.5 part by mass or less. When the upper limit of the content of the cross-linking agent (B) is the above, the cross-linking density of the obtained pressure-sensitive adhesive is made relatively small, thereby more effectively suppressing the occurrence of warpage in the constituent body (display body). be able to.

(1-3) Active energy ray curable component (C)
By containing the active energy ray-curable component (C) in the adhesive composition P, the adhesive obtained by crosslinking (thermally crosslinking) the adhesive composition P becomes an active energy ray-curable adhesive. .. This active energy ray-curable pressure-sensitive adhesive is such that the active energy ray-curable component (C) is polymerized with each other by curing by irradiation with the active energy ray after application of the adherend, and the polymerized active energy ray-curable component (C). Is entangled with the crosslinked structure (three-dimensional network structure) of the (meth)acrylic acid ester polymer (A). The pressure-sensitive adhesive having such a higher-order structure has high cohesive force and high coating strength, and therefore has excellent blister resistance.

The active energy ray-curable component (C) is not particularly limited as long as it is a component that is cured by irradiation with active energy rays and can obtain the above effects, and may be any of a monomer, an oligomer and a polymer. It may be a mixture of. Above all, a polyfunctional acrylate-based monomer that is more excellent in blister resistance and can more effectively suppress the occurrence of warpage in the constituent body (display body) can be preferably mentioned.

Examples of the polyfunctional acrylate-based monomer include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate. , Neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified diphosphoric acid di(meth)acrylate 2) such as (meth)acrylate, di(acryloxyethyl)isocyanurate, allylated cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene Functional type: trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth) ) Trifunctional types such as acrylate, tris(acryloxyethyl) isocyanurate, and ε-caprolactone modified tris-(2-(meth)acryloxyethyl) isocyanurate; diglycerin tetra(meth)acrylate, pentaerythritol tetra(meth) 4-functional type such as acrylate; 5-functional type such as propionic acid-modified dipentaerythritol penta(meth)acrylate; 6-functional type such as dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate Can be mentioned. Among the above, from the viewpoint of the blister resistance and warp suppressing effect of the obtained pressure-sensitive adhesive, di(acryloxyethyl)isocyanurate, tris(acryloxyethyl)isocyanurate, ε-caprolactone-modified tris-(2-(meth)) A polyfunctional acrylate-based monomer having an isocyanurate structure in a molecule such as acryloxyethyl) isocyanurate is preferable, and a polyfunctional acrylate-based monomer having a trifunctional or more and an isocyanurate structure in a molecule is more preferable. -Caprolactone-modified tris-(2-(meth)acryloxyethyl) isocyanurate is particularly preferred. These may be used alone or in combination of two or more. From the viewpoint of compatibility with the (meth)acrylic acid ester polymer (A), the polyfunctional acrylate-based monomer preferably has a molecular weight of less than 1,000.

As the active energy ray-curable component (C), an active energy ray-curable acrylate-based oligomer can also be used. Examples of such acrylate oligomers include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, and silicone acrylate.

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

Further, as the active energy ray-curable component (C), an adduct acrylate-based polymer in which a group having a (meth)acryloyl group is introduced into a side chain can also be used. Such an adduct acrylate-based polymer uses a copolymer of (meth)acrylic acid ester and a monomer having a crosslinkable functional group in the molecule, and uses it as a part of the crosslinkable functional group of the copolymer. , A (meth)acryloyl group and a compound having a group capable of reacting with a crosslinkable functional group.

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

As the active energy ray-curable component (C), one kind may be selected from the above-mentioned polyfunctional acrylate-based monomers, acrylate-based oligomers and adduct acrylate-based polymers, or two or more kinds may be used in combination. It is also possible to use it in combination with other active energy ray-curable components.

The content of the active energy ray-curable component (C) in the pressure-sensitive adhesive composition P is (meth)acrylic acid ester weight from the viewpoint of improving the cohesive force of the obtained pressure-sensitive adhesive and making the blister resistance excellent. The lower limit is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and particularly preferably 4 parts by mass or more with respect to 100 parts by mass of the combined (A). On the other hand, the content is preferably 20 parts by mass or less as an upper limit, more preferably 10 parts by mass or less, and 8 parts by mass or less from the viewpoint of further improving the warp suppressing effect. It is particularly preferable that the amount is 6 parts by mass or less.

(1-4) Photopolymerization initiator (D)
The photopolymerization initiator (D) in this embodiment has an absorbance of 0.3 or more at a wavelength of 390 nm in an acetonitrile solution having a concentration of 0.1% by mass. Since the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 11 contains such a photopolymerization initiator (D), the pressure-sensitive adhesive layer 11 can be irradiated with active energy rays through the ultraviolet ray shielding member. (Active energy ray-curable component (C)) is cured well, and the cured pressure-sensitive adhesive layer 11′ having excellent blister resistance is formed.

From the above viewpoint, the absorbance of the photopolymerization initiator (D) at a wavelength of 390 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 exceeds 2.5, the curing reaction of the active energy ray-curable component (C) by the photopolymerization initiator (D) proceeds due to the ambient light such as a fluorescent lamp during the formation of the pressure-sensitive adhesive sheet or the storage thereof, and thereafter. There is a case where the step followability during use is deteriorated. Here, the method for measuring the absorbance of the photopolymerization initiator (D) is as shown in the test example described later.

Further, the photopolymerization initiator (D) preferably has an absorption maximum wavelength of 350 nm or more of the absorbance at a wavelength of 200 to 500 nm in an acetonitrile solution having a concentration of 0.1% by mass, and particularly preferably 370 nm or more. Is preferably 380 nm or more. When there are a plurality of absorption maximum wavelengths of absorbance of 200 to 500 nm, at least one absorption maximum wavelength may be in the above range. Thereby, when the pressure-sensitive adhesive layer 11 is irradiated with an active energy ray through the ultraviolet shielding member, the curability of the pressure-sensitive adhesive layer 11 (active energy ray-curable component (C)) is further improved and formed. The blister resistance of the pressure-sensitive adhesive layer 11′ after curing becomes more excellent. On the other hand, the upper limit of the absorption maximum wavelength is not particularly limited, but from the viewpoint of preventing the progress of the curing reaction when the pressure-sensitive adhesive layer 11 is stored in ambient light, it is preferably 450 nm or less, and particularly 410 nm or less. It is preferable that the thickness is 405 nm or less, and further preferably 405 nm or less.

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

The content of the photopolymerization initiator (D) in the adhesive composition P is preferably 2 parts by mass or more as a lower limit value with respect to 100 parts by mass of the active energy ray-curable component (C), and particularly, It is preferably 4 parts by mass or more, and more preferably 6 parts by mass or more. The upper limit of the content of the photopolymerization initiator (D) is preferably 20 parts by mass or less, particularly preferably 18 parts by mass or less, and further preferably 15 parts by mass or less. ..

(1-5) Silane coupling agent (E)
It is preferable that the adhesive composition P further contains a silane coupling agent (E). Thereby, whether the adherend is a plastic plate or a glass member, the adhesion to the adherend is improved and the blister resistance is further improved.

The silane coupling agent (E) is an organosilicon compound having at least one alkoxysilyl group in the molecule, has good compatibility with the (meth)acrylic acid ester polymer (A), and has high light transmittance. Those having are preferable.

Examples of the silane coupling agent (E) include a polymerizable unsaturated group-containing silicon compound such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, Silicon compounds having an epoxy structure such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, mercapto groups such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane and 3-mercaptopropyldimethoxymethylsilane Containing silicon compounds, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and other amino groups Silicon compound, 3-chloropropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or at least one of these, and an alkyl group such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, or ethyltrimethoxysilane Examples thereof include a condensate with a silicon compound. These may be used alone or in combination of two or more.

The content of the silane coupling agent (E) in the adhesive composition P is preferably 0.01 parts by mass or more, and particularly preferably 100 parts by mass with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A). The amount is preferably 0.05 part by mass or more, and more preferably 0.1 part by mass or more. Further, the content is preferably 1 part by mass or less, particularly preferably 0.5 part by mass or less, and further preferably 0.3 part by mass or less.

(1-6) Various additives In the adhesive composition P, if desired, various additives usually used in acrylic pressure-sensitive adhesives such as an ultraviolet absorber, an antistatic agent, a tackifier, an antioxidant, A light stabilizer, a softening agent, a filler, a refractive index adjusting agent, a rust preventive and the like can be added. The polymerization solvent and the diluent solvent described below are not included in the additives that constitute the adhesive composition P.

However, it is preferable that the adhesive composition P does not contain an ultraviolet absorber. The ultraviolet absorber may bleed out from the adhesive (adhesive layer after curing) and may contaminate the resulting display. In the present embodiment, at least one of the one display member forming member and the other display member forming member can be an ultraviolet shielding member, and in that case, it is necessary that the adhesive layer after curing contains an ultraviolet absorbent. Is low.

(2) Production of Adhesive Composition Adhesive composition P was produced by producing (meth)acrylic acid ester polymer (A), and obtained (meth)acrylic acid ester polymer (A) and cross-linking agent ( It can be produced by mixing B), the active energy ray-curable component (C) and the photopolymerization initiator (D) and, if desired, adding a silane coupling agent (E) and an additive. ..

The (meth)acrylic acid ester polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by an ordinary radical polymerization method. The polymerization of the (meth)acrylic acid ester polymer (A) is preferably carried out by a solution polymerization method, optionally using a polymerization initiator. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, and the like, and two or more kinds may be used in combination.

Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more kinds may be used in combination. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methylbutyronitrile), 1,1′-azobis(cyclohexane1-carbonitrile), and ,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-hydroxymethylpropionitrile),2,2'-azobis[2-(2-imidazolin-2-yl) Propane] and the like.

Examples of the organic peroxide include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl)peroxy. Dicarbonate, t-butyl peroxy neodecanoate, t-butyl peroxy vivarate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like can be mentioned.

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

When the (meth)acrylic acid ester polymer (A) is obtained, the solution of the (meth)acrylic acid ester polymer (A) is added to the crosslinking agent (B), the active energy ray-curable component (C), and photopolymerization initiation. By adding the agent (D), and optionally the silane coupling agent (E) and the additive, and mixing them sufficiently, a tacky composition P (coating solution) diluted with a solvent can be obtained. In any of the above components, when a solid one is used, or when precipitation occurs when mixed with other components in an undiluted state, the component alone is previously diluted with a diluting solvent. It may be dissolved or diluted and then mixed with other components.

Examples of the diluent solvent include hexane, heptane, aliphatic hydrocarbons such as cyclohexane, toluene, aromatic hydrocarbons such as xylene, methylene chloride, halogenated hydrocarbons such as ethylene chloride, methanol, ethanol, propanol, butanol, Alcohols such as 1-methoxy-2-propanol, acetone, methyl ethyl ketone, ketones such as 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve are used.

The concentration/viscosity of the coating solution thus prepared is not particularly limited as long as it can be coated, and can be appropriately selected depending on the situation. For example, the pressure-sensitive adhesive composition P is diluted so as to have a concentration of 10 to 60% by mass. In addition, when obtaining the coating solution, addition of a diluting solvent or the like is not a necessary condition, and the diluting solvent may not be added as long as the viscosity of the adhesive composition P allows the coating. In this case, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth)acrylic acid ester polymer (A) as a diluting solvent.

(3) Formation of active energy ray-curable pressure-sensitive adhesive layer The pressure-sensitive adhesive layer 11 is composed of an active energy ray-curable pressure-sensitive adhesive obtained by crosslinking the adhesive composition P (thermal crosslinking). The crosslinking of the adhesive composition P can be performed by heat treatment. In addition, this heat treatment can also serve as a 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. Furthermore, it is particularly preferable to provide a curing period of about 1 to 2 weeks at room temperature (for example, 23° C. and 50% RH) after the heat treatment.

By the above heat treatment (and curing), the (meth)acrylic acid ester polymer (A) is satisfactorily crosslinked through the crosslinking agent (B).

(4) Thickness of pressure-sensitive adhesive layer The thickness of the pressure-sensitive adhesive layer 11 (value measured according to JIS K7130) is preferably 10 μm or more as a lower limit, more preferably 20 μm or more, and particularly 25 μm. It is preferably not less than 50 μm, more preferably not less than 50 μm. The upper limit of the thickness of the adhesive layer 11 is preferably 500 μm or less, more preferably 400 μm or less, particularly preferably 300 μm or less, and further preferably 250 μm or less. When the thickness of the pressure-sensitive adhesive layer 11 is in the relatively thick range as described above, the deviation caused by the difference in shrinkage ratio between the two display member components becomes easier to be alleviated by the pressure-sensitive adhesive layer after curing, and thus the warp suppressing effect is obtained. Will be better.

1-2. Release Sheet The release sheets 12a and 12b protect the active energy ray-curable pressure-sensitive adhesive layer 11 until the optical pressure-sensitive adhesive sheet 1 is used, and when the optical pressure-sensitive adhesive sheet 1 (pressure-sensitive adhesive layer 11) is used. Is peeled off. In the optical pressure-sensitive adhesive sheet 1 according to the present embodiment, one or both of the release sheets 12a and 12b are not always necessary.

Examples of the release sheets 12a and 12b include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene. Terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluorine A resin film or the like is used. Further, these crosslinked films are also used. Furthermore, these laminated films may be used.

It is preferable that the release surface of each of the release sheets 12a and 12b (particularly the surface in contact with the pressure-sensitive adhesive layer 11) is subjected to a release treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. It is preferable that one of the release sheets 12a and 12b 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 low release force.

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

2. Production of optical pressure-sensitive adhesive sheet As one production example of the optical pressure-sensitive adhesive sheet 1, a release surface of one release sheet 12a (or 12b) is coated with the coating solution of the pressure-sensitive adhesive composition P and heat-treated. After the pressure-sensitive adhesive composition P is thermally crosslinked to form a coating layer, the release surface of the other release sheet 12b (or 12a) is superposed on the coating layer. When the curing period is required, the curing period is set, and when the curing period is not necessary, the coating layer becomes the active energy ray-curable pressure-sensitive adhesive layer 11 as it is. Thereby, the optical pressure-sensitive adhesive sheet 1 is obtained. The heat treatment and curing conditions are as described above.

As another production example of the optical pressure-sensitive adhesive sheet 1, the release surface of one release sheet 12a is coated with the coating solution of the pressure-sensitive adhesive composition P, and heat treatment is performed to thermally crosslink the pressure-sensitive adhesive composition P. Then, the coating layer is formed to obtain the release sheet 12a with the coating layer. In addition, a coating solution of the adhesive composition P is applied to the release surface of the other release sheet 12b, heat treatment is performed to thermally crosslink the adhesive composition P, a coating layer is formed, and a coating layer is provided. To obtain a release sheet 12b. Then, the release sheet 12a with the coating layer and the release sheet 12b with the coating layer are attached to each other so that the both coating layers are in contact with each other. When the curing period is required, the curing period is set, and when the curing period is not necessary, the above-mentioned laminated coating layers become the active energy ray-curable pressure-sensitive adhesive layer 11. Thereby, the optical pressure-sensitive adhesive sheet 1 is obtained. According to this manufacturing example, even if the pressure-sensitive adhesive layer 11 is thick, it is possible to manufacture it stably.

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

3. Physical Properties (1) Gel Fraction The gel fraction of the active energy ray-curable pressure-sensitive adhesive (before irradiation with active energy rays) that constitutes the pressure-sensitive adhesive layer 11 is preferably 30% or more as a lower limit, and 40% or more. It is more preferable that it is present, and it is particularly preferable that it is 45% or more. When the lower limit value of the gel fraction of the active energy ray-curable pressure-sensitive adhesive is the above, the pressure-sensitive adhesive has a predetermined cohesive force, and when the optical pressure-sensitive adhesive sheet 1 is cut, the pressure-sensitive adhesive is applied to the blade. Adhesion and exudation of the pressure-sensitive adhesive from the pressure-sensitive adhesive layer 11 during storage or the like are effectively suppressed. The gel fraction of the active energy ray-curable pressure-sensitive adhesive is preferably 70% or less as an upper limit value, particularly preferably 65% or less, and further preferably 60% or less. When the upper limit of the gel fraction of the active energy ray-curable pressure-sensitive adhesive is the above, the pressure-sensitive adhesive after curing with active energy rays does not become too hard, and the warp suppressing effect of the pressure-sensitive adhesive layer after curing becomes more excellent. .. The method for measuring the gel fraction of this active energy ray-curable pressure-sensitive adhesive is as shown in the test example described later.

Further, the increase in gel fraction accompanying the curing of the active energy ray-curable pressure-sensitive adhesive by irradiation with active energy rays is 5 points or more, preferably 10 points or more, and particularly preferably 15 points or more. By increasing the gel fraction in this way, the obtained cured pressure-sensitive adhesive layer becomes more excellent in blister resistance. The upper limit of the increase of the gel fraction is not particularly limited, but the increase of the gel fraction is preferably 40 points or less from the viewpoint of preventing the pressure-sensitive adhesive layer from becoming too hard after curing. , 30 points or less is more preferable, and 25 points or less is particularly preferable.

(2) Adhesive Strength Soda-lime glass of the optical pressure-sensitive adhesive sheet 1 when the pressure-sensitive adhesive layer 11 of the optical pressure-sensitive adhesive sheet 1 according to the present embodiment is cured by irradiation with active energy rays to be a pressure-sensitive adhesive layer after curing. The lower limit of the adhesive force to 5N/25 mm is preferably 5 N/25 mm or more, more preferably 10 N/25 mm or more, and further preferably 20 N/25 mm or more. When the lower limit of the adhesive strength of the optical pressure-sensitive adhesive sheet 1 is the above, the blister resistance becomes more excellent. On the other hand, the upper limit of the adhesive strength is not particularly limited, but is usually preferably 100 N/25 mm or less, more preferably 90 N/25 mm or less, and particularly preferably 80 N/25 mm or less. The above-mentioned adhesive force basically means an adhesive force measured by a 180-degree peeling method according to JIS Z0237:2009, and the specific test method is as shown in the test examples described later.

(Structure)
A structure according to an embodiment of the present invention is a pressure-sensitive adhesive layer that bonds one display member forming member, another display member forming member, and one display member forming member and another display member forming member to each other. And is configured. At least one of the one display member constituting member and the other display member constituting member is an ultraviolet shielding member having an ultraviolet shielding property. Further, the one display member forming member and the other display member forming member are made of materials having different linear expansion coefficients. The structural body according to the present embodiment may be one member forming the display body or the display body itself.

For the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, 10% strain due to torsional shearing is continuously applied according to JIS K7244-1, and the relaxation elastic modulus measured 10 minutes after the strain application is 0.1 kPa. As described above, it is 15 kPa or less. Further, the gel fraction of the pressure-sensitive adhesive is 60% or more and 90% or less. The constitutional body provided with the pressure-sensitive adhesive layer satisfying these physical properties suppresses the occurrence of warpage and is also excellent in blister resistance. In particular, when the relaxation elastic modulus of the pressure-sensitive adhesive is in the above range, even when the above-mentioned constituent is placed under high temperature conditions, for example, under conditions of 85° C. and 85% RH for 72 hours, the shrinkage of the two indicator constituent members occurs. The shift due to the difference in rate can be mitigated by the pressure-sensitive adhesive layer, so that the warp of the structural body can be suppressed. Moreover, in particular, when the gel fraction of the pressure-sensitive adhesive is within the above range, the pressure-sensitive adhesive has a predetermined cohesive force. Thus, the above structure, in particular, one of the display member constituting member is a plastic plate that generates outgas under the conditions of high temperature and high humidity, or permeates water vapor. Even when left under the condition of 85% RH for 72 hours, the occurrence of blisters such as bubbles, floating, and peeling at the interface between the display member and the pressure-sensitive adhesive layer is suppressed.

From the above viewpoint, the lower limit of the relaxation elastic modulus of the pressure-sensitive adhesive is preferably 1 kPa or more, and particularly preferably 3 kPa or more. On the other hand, the upper limit of the relaxation elastic modulus of the pressure-sensitive adhesive is preferably 10 kPa or less, particularly 5.5 kPa or less, and further preferably 5.0 kPa or less. From the above viewpoint, the lower limit of the gel fraction of the pressure-sensitive adhesive is preferably 64% or more, and particularly preferably 68% or more. On the other hand, the upper limit of the gel fraction of the pressure-sensitive adhesive is preferably 84% or less, and particularly preferably 78% or less. The specific methods for measuring the relaxation elastic modulus and gel fraction of the pressure-sensitive adhesive are as shown in the test examples described later.

The pressure-sensitive adhesive layer is preferably a cured pressure-sensitive adhesive layer that is cured by irradiation with active energy rays. Hereinafter, the case where the pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer after curing will be mainly described. However, the pressure-sensitive adhesive layer of the structure according to the present invention is not limited to the pressure-sensitive adhesive layer after curing.

Here, in the structure according to the present embodiment, when the pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer after curing, and only one display body component member is the ultraviolet shielding member, on the side that is not the ultraviolet shielding member. The display member is a member whose performance is deteriorated by irradiation of ultraviolet rays, or a member having a structure in which the adhesive layer cannot be irradiated with active energy rays from the side of the display member which is not the ultraviolet shielding member. Preferably. Even when a member having such a constraint is used as a display member, if the optical pressure-sensitive adhesive sheet 1 according to the above-described embodiment is used, active energy rays can be irradiated from the ultraviolet shielding member side. As a result, the pressure-sensitive adhesive layer 11 is sufficiently cured to become a pressure-sensitive adhesive layer after curing, and a structure having excellent blister resistance can be obtained.

As shown in FIG. 2, the structure 2 according to the embodiment of the present invention includes a first display member forming member 21 (one display member forming member) and a second display member forming member 22 (another display member). Body component) and a pressure-sensitive adhesive layer 11' (preferably cured by irradiation with active energy rays) which is located between them and which bonds the first display component component 21 and the second display component component 22 to each other. The pressure-sensitive adhesive layer after curing, which will be hereinafter referred to as “post-curing pressure-sensitive adhesive layer 11′”). In the structure 2 according to the present embodiment, the first display member forming member 21 has a step on the surface on the side of the pressure-sensitive adhesive layer 11 ′ after curing, and specifically, has a step due to the printing layer 3. However, the present invention is not limited to this.

The post-curing pressure-sensitive adhesive that constitutes the post-curing pressure-sensitive adhesive layer 11 ′ included in the above-mentioned structure 2 has the relaxation elastic modulus and gel fraction as described above. The pressure-sensitive adhesive layer 11 ′ after curing is preferably a layer obtained by curing the pressure-sensitive adhesive layer 11 of the optical pressure-sensitive adhesive sheet 1 described above by irradiation with active energy rays. It is generally difficult to make the relaxation elastic modulus and the gel fraction compatible with each other. However, by using the optical pressure-sensitive adhesive sheet 1, the post-curing pressure-sensitive adhesive forming the post-curing pressure-sensitive adhesive layer 11' tends to satisfy the relaxation elastic modulus and gel fraction described above. However, the present invention is not limited to the one using the optical pressure-sensitive adhesive sheet 1.

In this case, the post-curing pressure-sensitive adhesive that constitutes the post-curing pressure-sensitive adhesive layer 11′ has a cross-linked structure composed of at least the (meth)acrylic acid ester polymer (A) and the cross-linking agent (B), and has active energy. It contains a cured product (polymerized product) of the line-curable component (C), and optionally further contains a photopolymerization initiator (D) and an additive. Here, the polymerized active energy ray-curable component (C) is entangled in a crosslinked structure composed of the (meth)acrylic acid ester polymer (A) and the crosslinking agent (B) to form a higher-order structure. Presumed to be present.

The photopolymerization initiator (D) contained in the post-curing pressure-sensitive adhesive that constitutes the post-curing pressure-sensitive adhesive layer 11′ is the same as the photopolymerization initiator (D) contained in the pressure-sensitive adhesive composition P. It remained without being cleaved by the irradiation of rays. Therefore, the content thereof is not large, and is usually 0.0001% by mass or more and 0.1% by mass or less in the adhesive, preferably 0.0001% by mass or more and 0.01% by mass or less. ..

The gel fraction of the pressure-sensitive adhesive after curing constituting the pressure-sensitive adhesive layer 11' after curing is as described above, but is 5 points higher than the gel fraction of the active energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 11. It is a value increased above, preferably a value increased by 10 points or more, particularly preferably a value increased by 15 points or more.

The haze value of the pressure-sensitive adhesive layer 11′ after curing is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and further 0.5% or less. It is preferable. When the haze value of the pressure-sensitive adhesive layer 11' after curing is 5% or less, the transparency is very high, which is suitable for optical use (for display). The haze value in this specification is a value measured according to JIS K7136:2000.

The transparent hue b ^* defined by the CIE1976L ^* a ^* b ^* color system of the pressure-sensitive adhesive layer 11′ after curing is preferably −3.0 to 3.0, and particularly −2.0 to 2. It is preferably 0, more preferably -1.5 to 1.5. When b ^{* of the} cured pressure-sensitive adhesive layer 11′ is in the above range, the yellow color of the cured pressure-sensitive adhesive layer 11′ is suppressed, and the appearance and visibility of the display are improved. The method of measuring b ^* is as shown in the test example described later.

In the structure 2 according to the present embodiment, at least one of the first display member forming member 21 and the second display member forming member 22 is an ultraviolet light shielding member having an ultraviolet light shielding property. As described above, the ultraviolet ray blocking member has a light transmittance of 20% or less at a wavelength of 360 nm, a light transmittance of 10% or more at a wavelength of 390 nm, and a light transmittance of a wavelength of 360 nm is at a light transmittance of 390 nm. It is higher than the transmittance. The measuring method of the light transmittance in this specification is as shown in the test example described later.

When the ultraviolet ray blocking member has a light transmittance of 10% or more at a wavelength of 390 nm, the photopolymerization initiator (D) is emitted when the adhesive layer 11 is irradiated with active energy rays through the ultraviolet ray blocking member. Cleaves without problems. As a result, the curing reaction of the active energy ray-curable component (C) proceeds well, the pressure-sensitive adhesive layer 11 is sufficiently cured, and the cured pressure-sensitive adhesive layer 11' having excellent blister resistance is formed. From this point of view, the lower limit of the light transmittance of the ultraviolet ray blocking member at the wavelength of 390 nm is 20% or more, preferably 40% or more, and particularly preferably 50% or more. The upper limit of the light transmittance of the ultraviolet ray blocking member at a wavelength of 390 nm is not particularly limited, but usually it is preferably 98% or less, and particularly preferably 85% or less.

On the other hand, when the light transmittance of the ultraviolet ray shielding member at a wavelength of 360 nm is 20% or less, the active energy ray that easily yellows the pressure-sensitive adhesive layer 11′ after curing is blocked by the ultraviolet ray shielding member, and the pressure sensitive adhesive agent after curing. It is difficult to reach the layer 11'. Thereby, yellowing of the pressure-sensitive adhesive layer 11' after curing is suppressed. From this point of view, the light transmittance of the ultraviolet ray blocking member at a wavelength of 360 nm is 10% or less, preferably 5% or less, and particularly preferably 1% or less, as an upper limit value. The lower limit of the light transmittance of the ultraviolet ray blocking member at a wavelength of 360 nm is not particularly limited, but is usually preferably 0.01% or more, and particularly preferably 0.1% or more.

The ultraviolet shielding member is preferably made of a plastic plate, and particularly preferably made of a plastic plate containing an ultraviolet absorber. Here, the plastic plate usually has a low boiling point component vaporized when placed under high temperature conditions, for example, at 85° C., and at the interface between the plastic plate and the pressure-sensitive adhesive layer 11′ after curing, Blisters such as air bubbles, floating, and peeling may occur. However, even if the structure 2 according to the present embodiment includes such a plastic plate, the cured pressure-sensitive adhesive layer 11 ′ is derived from the optical pressure-sensitive adhesive sheet 1 according to the present embodiment. The occurrence of blisters can be suppressed well.

The plastic plate is not particularly limited, and examples thereof include acrylic resin plates such as polycarbonate resin (PC) plates and polymethylmethacrylate resin (PMMA) plates, and acrylic resin such as polymethylmethacrylate resin layers on polycarbonate resin plates. Examples include a plastic plate in which layers are laminated. The polycarbonate resin plate described above may contain a resin other than a polycarbonate resin as a material forming the same, and the acrylic resin plate described above may contain a resin other than an acrylic resin as a material forming the same. May be included.

The thickness of the plastic plate is not particularly limited, but is usually 0.2 to 5 mm, preferably 0.4 to 3 mm, particularly preferably 0.6 to 2.5 mm, and further preferably 1 to It is 2.1 mm.

The first display member constituting member 21 is preferably a protective panel made of the above-mentioned ultraviolet ray shielding member. Various functional layers (a transparent conductive film, a metal layer, a silica layer, a hard coat layer, an antiglare layer, etc.) may be provided on one side or both sides of the ultraviolet shielding member, or an optical member is laminated. May be. Moreover, the transparent conductive film and the metal layer may be patterned.

The first display body component 21 and the second display body component 22 are made of materials having different linear expansion coefficients. Therefore, when the first display body constituting member 21 is made of a plastic plate as described above, the second display body constituting member 22 is made of a material having a linear expansion coefficient different from that of the plastic plate. .. The second display member 22 is preferably a glass plate or a member having a linear expansion coefficient equivalent to that of the glass plate.

The linear expansion coefficient of the first display body constituting member 21 is preferably 2 times or more, particularly preferably 3 times or more, and further 5 times the linear expansion coefficient of the second display body constituting member 22. The above is preferable. The linear expansion coefficient of the first display body component 21 is preferably 1000 times or less, particularly preferably 100 times or less, the linear expansion coefficient of the second display body component 22. It is preferably 10 times or less.

The second display member constituting member 22 may be specifically a glass plate, or an optical member to be attached to the first display member constituting member 21 or a display member module (for example, liquid crystal (LCD)). Module, light emitting diode (LED) module, organic electroluminescence (organic EL) module, etc.), an optical member as a part of the display module, or a laminated body including the display module. The optical member, the display module, the laminated body, and the like may include a glass plate.

The glass plate is not particularly limited, for example, chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, barium-strontium-containing glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate Examples include glass. The thickness of the glass plate is not particularly limited, but is usually 0.1 to 10 mm, preferably 0.2 to 5 mm, more preferably 0.8 to 2 mm.

Even if various functional layers (a transparent conductive film, a metal layer, a silica layer, a hard coat layer, an antiglare layer, etc.) are provided on one surface or both surfaces of the glass plate constituting the second display member constituting member 22. The optical members may be laminated. Moreover, the transparent conductive film and the metal layer may be patterned.

Examples of the optical member include a shatterproof film, a polarizing plate (polarizing film), a polarizer, a retardation film (retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, a diffusion film. , A transflective film, a transparent conductive film, and the like. Examples of the anti-scattering film include a hard coat film in which a hard coat layer is formed on one surface of a base film. The optical member may contain an ultraviolet absorber.

Further, the second display member constituting member 22 is a member whose performance is deteriorated by ultraviolet irradiation, or the active energy ray curable pressure sensitive adhesive layer 11 from the side of the second display member constituting member 22 to the active energy ray. It is preferable that the member has a structure that cannot irradiate. Specifically, it is preferable that the second display body constituent member 22 is a display body module or a laminated body including the display body module.

When the first display member constituting member 21 is a protective panel, the printing layer 3 is generally formed in a frame shape on the cured adhesive layer 11 ′ side of the first display member constituting member 21. is there.

The material forming the print layer 3 is not particularly limited, and a known material for printing is used. The thickness of the printed layer 3, that is, the height of the step is usually about 3 to 50 μm. The post-curing pressure-sensitive adhesive layer 11 ′ can exhibit sufficient followability even with such a printing layer 3, and bubbles or the like can be prevented from being generated at the interface with the printing layer 3.

The constituent body 2 may be, for example, a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, a member constituting a part of the display body such as electronic paper, or the like. It may be the display itself. The display may be a touch panel.

In order to manufacture the above-mentioned structure 2, as an example, one release sheet 12a of the optical pressure-sensitive adhesive sheet 1 is peeled off, and the exposed pressure-sensitive adhesive layer 11 of the optical pressure-sensitive adhesive sheet 1 is fixed to the first display member constituting member. 21 is attached to the surface on the side where the printing layer 3 is present. At this time, since the pressure-sensitive adhesive layer 11 is excellent in the initial step followability, it is possible to suppress the occurrence of a gap or a float near the step due to the printing layer 3.

Next, the other release sheet 12b is peeled from the pressure-sensitive adhesive layer 11 of the optical pressure-sensitive adhesive sheet 1, and the exposed pressure-sensitive adhesive layer 11 of the optical pressure-sensitive adhesive sheet 1 and the second display member 22 are bonded together. Obtain a laminate. Further, as another example, the bonding order of the first display body constituting member 21 and the second display body constituting member 22 may be exchanged.

After obtaining the above-mentioned laminated body, the adhesive layer 11 in the laminated body is irradiated with an active energy ray through a display body constituting member which is an ultraviolet ray shielding member, preferably the first display body constituting member 21. To do. As described above, since the active energy ray having the wavelength for curing the pressure-sensitive adhesive layer 11 passes through the ultraviolet shielding member, the pressure-sensitive adhesive layer 11 is sufficiently cured by the irradiation of the active energy ray and the pressure-sensitive adhesive after curing is used. This will be layer 11'. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 11' after curing has the relaxation elastic modulus and gel fraction described above. Thereby, the structural body 2 excellent in the blister resistance and the effect of suppressing the warp can be obtained.

As described above, the active energy ray used in this embodiment emits light with a substantial intensity in the wavelength region exceeding the wavelength of 365 nm. Preferable examples of such an active energy ray irradiation light source include a high pressure mercury lamp, a metal halide lamp, and a xenon lamp. The irradiation amount of the active energy ray is preferably such that the illuminance is about 50 to 1000 mW/cm ² . Further, the light quantity is preferably 50~10000mJ / cm ^2, more preferably 80~5000mJ / cm ^2, and particularly preferably 200~2000mJ / cm ^2.

In the above-mentioned structure 2, the active energy rays in the wavelength range where the pressure sensitive adhesive is easily yellowed are shielded by the display body constituting member (first display body constituting member 21) which is an ultraviolet ray shielding member, and the pressure sensitive adhesive after curing. Difficult to reach layer 11'. Thereby, yellowing of the pressure-sensitive adhesive layer 11' after curing can be suppressed.

[Display]
A display body according to an embodiment of the present invention includes the above-described constituent body 2, and may consist of only the constituent body 2, or the constituent body 2 and another constituent body 2 or another display body structure. And a member. When the constituent body 2 and another constituent body 2 or another display body constituent member are laminated, the pressure-sensitive adhesive layer 11 of the optical pressure-sensitive adhesive sheet 1 described above may be used for lamination. In this case, the pressure-sensitive adhesive layer 11 is cured by irradiation with active energy rays to obtain a cured pressure-sensitive adhesive layer 11'.

Examples of the display body according to the present embodiment include a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, electronic paper, and the like, and may be a touch panel.

The embodiments described above are described to facilitate the understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above-described embodiment is intended to include all design changes and equivalents within the technical scope of the present invention.

For example, one of the release sheets 12a and 12b in the optical pressure-sensitive adhesive sheet 1 may be omitted. The first display member 21 may have a step other than the printing layer 3 or may not have a step. Furthermore, not only the first display body constituting member 21 but also the second display body constituting member 22 may have a step on the pressure-sensitive adhesive layer 11' side after curing.

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

[Example 1]
1. Preparation of (meth)acrylic acid ester polymer (A) 75 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of N-acryloylmorpholine, 10 parts by mass of isobornyl acrylate, and 5 parts by mass of 2-hydroxyethyl acrylate were used as solution weights. Copolymerization was carried out by a conventional method to prepare a (meth)acrylic acid ester polymer (A). When the molecular weight of this (meth)acrylic acid ester polymer (A) was measured by the method described below, the weight average molecular weight (Mw) was 500,000.

2. Preparation of Adhesive Composition 100 parts by mass of (meth)acrylic acid ester polymer (A) obtained in the above step 1 (solid content conversion value; the same applies below) and trimethylolpropane-modified triester as a crosslinking agent (B). 0.15 parts by mass of diisocyanate (manufactured by Toyochem, product name “BHS8515”) and ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate (Shin-Nakamura Chemical Co., Ltd.) as an active energy ray-curable component (C). Manufactured by the company, product name "A-9300-1CL") 5 parts by mass, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (D1) 0.5 part by mass as a photopolymerization initiator (D). , 0.25 parts by mass of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBM-403") as a silane coupling agent, mixed sufficiently, and diluted with methyl ethyl ketone. By doing so, a coating solution of the adhesive composition was obtained.

Here, Table 1 shows each compounding (solid content conversion value) of the adhesive composition when the (meth)acrylic acid ester polymer (A) was 100 parts by mass (solid content conversion value). The details of the abbreviations listed in Table 1 are as follows.
[(Meth)acrylic acid ester polymer (A)]
2EHA: 2-ethylhexyl acrylate ACMO: N-acryloylmorpholine IBXA: isobornyl acrylate HEA: 2-hydroxyethyl acrylate BA: n-butyl acrylate MA: methyl acrylate
[Crosslinking agent (B)]
TDI: trimethylolpropane modified tolylene diisocyanate (manufactured by Toyochem, product name "BHS8515")
XDI: trimethylolpropane modified xylylene diisocyanate (manufactured by Soken Chemical Industry Co., Ltd., product name "TD-75")
[Photopolymerization initiator (D)]
D1:2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide D2:1-hydroxy-cyclohexyl-phenyl-ketone

3. Production of optical pressure-sensitive adhesive sheet A heavy-release type peeling sheet (manufactured by Lintec Co., product name "SP -PET 752150") was coated with a knife coater on the release-treated surface and then heat-treated at 90°C for 1 minute to form a coating layer (thickness: 50 µm). A light release type release sheet (a product name "SP-PET381130" manufactured by Lintec Co., Ltd.) in which the surface of the obtained heavy release type release sheet with a coating layer on the application layer side and one side of a polyethylene terephthalate film are release-treated with a silicone-based release agent. )) is bonded to the release treated surface and cured at 23° C. and 50% RH for 7 days to obtain a heavy release type release sheet/active energy ray-curable pressure-sensitive adhesive layer (thickness: 50 μm)/ An optical pressure-sensitive adhesive sheet having the structure of a light release type release sheet was produced.

The thickness of the pressure-sensitive adhesive layer is a value measured using a constant pressure thickness meter (manufactured by Teclock Co., product name “PG-02”) according to JIS K7130.

4. Production of pressure-sensitive adhesive sheet with cover material The light release type release sheet is peeled off from the optical pressure-sensitive adhesive sheet obtained in the above step 3, and the exposed active energy ray-curable pressure-sensitive adhesive layer is applied to a polycarbonate resin plate as a cover material. A plastic plate laminated with an acrylic resin layer such as a polymethylmethacrylate resin layer (manufactured by Mitsubishi Gas Chemical Co., Inc., product name "Iupilon sheet MR58", thickness: 1 mm, containing an ultraviolet absorber, linear expansion coefficient: 70×10 ^{− (6} /° C.) was attached to the surface of the polycarbonate resin plate side to obtain an adhesive sheet with a cover material. The cover material corresponds to an ultraviolet shielding member.

5. Manufacture of a structure The heavy release type release sheet is peeled off from the pressure-sensitive adhesive sheet with the cover material obtained in the above step 4, and the exposed active energy ray-curable pressure-sensitive adhesive layer is soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd., thickness : 1.1 mm, linear expansion coefficient: 9×10 ⁻⁶ /° C.). Then, autoclave treatment was carried out for 20 minutes under the conditions of 50° C. and 0.5 MPa, and the mixture was left standing at 23° C. and 50% RH for 24 hours under normal pressure.

Next, the active energy ray-curable pressure-sensitive adhesive layer was irradiated with an active energy ray through the cover material under the following conditions to cure the pressure-sensitive adhesive layer to obtain a cured pressure-sensitive adhesive layer. In this way, a structure in which the cover material (one display member constituting member which is an ultraviolet ray shielding member) and the glass plate (another display member forming member) were bonded together by the adhesive layer after curing was obtained.

<Activity energy irradiation conditions>
・Using a high-pressure mercury lamp ・Illuminance 200 mW/cm ² , light intensity 1000 mJ/cm ²
・"UVPF-A1" made by iGraphics Co., Ltd. is used for UV illuminance/photometer

[Examples 2 to 7, Comparative Examples 1 to 3]
Kind and ratio of each monomer constituting the (meth)acrylic acid ester polymer (A), weight average molecular weight of the (meth)acrylic acid ester polymer (A), kind and blending amount of the cross-linking agent (B), active energy Example 1 except that the compounding amount of the linear curable component (C), the type and compounding amount of the photopolymerization initiator (D), and the compounding amount of the silane coupling agent (E) were changed as shown in Table 1. In the same manner, an optical pressure-sensitive adhesive sheet, a cover material-attached pressure-sensitive adhesive sheet, and a structural body were manufactured.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).
<Measurement conditions>
-GPC measuring device: HLC-8020 manufactured by Tosoh Corporation
-GPC column (passed in the following order): Tosoh TSK guard column HXL-H
TSK gel GMHXL (x2)
TSK gel G2000HXL
・Measurement solvent: Tetrahydrofuran ・Measurement temperature: 40°C

[Test Example 1] (Measurement of absorbance)
Acetonitrile solutions having a concentration of 0.1% by mass of the photopolymerization initiator used in Examples and Comparative Examples were prepared, and the absorbance of the solution in the wavelength range of 200 to 500 nm was measured by UV-Vis-NIR (UV-Vis-NIR). ) It measured using the spectrophotometer (Shimadzu Corporation make, product name "UV-3600"). Based on the results, the absorption maximum wavelength (nm) at the absorbance at the wavelength of 390 nm and the absorbance at the wavelength of 200 to 500 nm was derived. The results are shown in Table 1.

[Test Example 2] (Measurement of light transmittance)
Cover material used in Examples and Comparative Examples (a plastic plate obtained by laminating an acrylic resin layer such as a polymethylmethacrylate resin layer on a polycarbonate resin plate, manufactured by Mitsubishi Gas Chemical Co., Inc., product name "Iupilon sheet MR58", thickness: The light transmittance (%) of 1 mm, containing an ultraviolet absorber was measured using a simultaneous photometric spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SQ2000"). As a result, the light transmittance at a wavelength of 360 nm was less than 1%, and the light transmittance at a wavelength of 390 nm was 54%.

[Test Example 3] (Measurement of gel fraction)
The optical pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were cut into a size of 80 mm×80 mm, the active energy ray-curable pressure-sensitive adhesive layer was wrapped in a polyester mesh (mesh size 200), and its mass was measured accurately. The weight of the pressure-sensitive adhesive alone was calculated by weighing with a balance and subtracting the weight of the mesh alone. The mass at this time is M1.

Next, the pressure-sensitive adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23° C.) for 72 hours. After that, the adhesive was taken out, air-dried for 24 hours in an environment of a temperature of 23° C. and a relative humidity of 50%, and further dried in an oven of 80° C. for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the mesh alone was subtracted to calculate the mass of the adhesive alone. The mass at this time is M2. The gel fraction (%) is represented by (M2/M1)×100. Thereby, the gel fraction (before the active energy ray irradiation) of the adhesive (active energy ray-curable adhesive) was derived. The results are shown in Table 2.

On the other hand, with respect to the pressure-sensitive adhesive sheets with cover materials obtained in Examples and Comparative Examples, through the cover material, active energy rays were irradiated under the following conditions to cure and cure the active energy ray-curable pressure-sensitive adhesive layer. It was used as a post adhesive layer. The gel fraction (after irradiation with active energy rays) of the pressure-sensitive adhesive in the pressure-sensitive adhesive layer after curing (pressure-sensitive adhesive after curing) was derived in the same manner as above. The results are shown in Table 2.

<Activity energy irradiation conditions>
・Using a high-pressure mercury lamp ・Illuminance 200 mW/cm ² , light intensity 1000 mJ/cm ²
・"UVPF-A1" made by iGraphics Co., Ltd. is used for UV illuminance/photometer

[Test Example 4] (Measurement of haze value)
The haze value of the pressure-sensitive adhesive layer after curing of the structures obtained in Examples and Comparative Examples was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name “NDH-2000”) in accordance with JIS K7136:2000. (%) was measured. The results are shown in Table 2.

[Test Example 5] (Measurement of transmission hue b ^* )
CIE1976L ^* a ^* b ^* was used for the cured adhesive layers of the constituents obtained in Examples and Comparative Examples using a simultaneous photometric spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd., product name “SQ2000”) ^. The transmission hue b ^* defined by the color system was measured. The results are shown in Table 2.

[Test Example 6] (Measurement of adhesive strength)
The light release-type release sheet was peeled from the optical pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, and the exposed active energy ray-curable pressure-sensitive adhesive layer was formed into a polyethylene terephthalate (PET) film (Toyobo Co., Ltd.). It was attached to an easy-adhesion layer having a product name of "PET A4300", thickness: 100 μm) to obtain a laminate of a heavy release-type release sheet/active energy ray-curable pressure-sensitive adhesive layer/PET film. The obtained laminate was cut into a width of 25 mm and a length of 100 mm.

In a 23° C., 50% RH environment, the heavy release type release sheet is released from the above laminate, and the exposed active energy ray-curable pressure-sensitive adhesive layer is attached to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.), It was pressurized at 0.5 MPa and 50° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho. Then, after leaving it for 24 hours under the condition of 23° C. and 50% RH, the PET film surface is turned to the upper side, and a cover material (manufactured by Mitsubishi Gas Chemical Co., Inc., product name “Iupilon sheet MR58”, thickness: 1 mm, UV absorber was included) was placed on the PET film. Then, through the cover material and the PET film, the active energy ray-curable pressure-sensitive adhesive layer is irradiated with active energy rays under the same active energy ray irradiation conditions as in Test Example 3 to cure the pressure-sensitive adhesive layer. After curing, it was used as an adhesive layer. After leaving it for 24 hours under the conditions of 23° C. and 50% RH, the cover material was removed, and the sample having the pressure-sensitive adhesive layer after curing was subjected to a tensile tester (Tensilon, manufactured by Orientec Co., Ltd.) and a peeling speed of 300 mm. The adhesive force (N/25 mm) was measured under the conditions of /min and a peeling angle of 180 degrees. Conditions other than those described here were measured according to JIS Z 0237:2009. The results are shown in Table 2. In addition, in Comparative Examples 2 and 3, cohesive failure occurred in which peeling occurred at portions other than the interface.

[Test Example 7] (Measurement of relaxation elastic modulus)
A plurality of active energy ray-curable pressure-sensitive adhesive layers of the optical pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were laminated to form a laminate having a thickness of 0.5 mm. The laminate is irradiated with active energy rays through the cover materials used in Examples and Comparative Examples under the same active energy ray irradiation conditions as in Test Example 3 to cure the laminate, and the cured laminate. And A columnar body (height: 0.5 mm) having a diameter of 8 mm was punched from the obtained cured laminate, and this was used as a sample.

Using a viscoelasticity measuring device (manufactured by Anton paar, product name “MCR302”), the sample was continuously subjected to torsional shear strain under the following conditions according to JIS K7244-1, and the strain was applied for 10 The relaxation elastic modulus (kPa) after the measurement was measured. The results are shown in Table 2.
Measurement temperature: 25°C
Strain: 10%
Measurement points: 1000 points (logarithmic plot)
In addition, in Comparative Examples 2 and 3, since it was not possible to obtain a laminate after curing that was cured to the extent that the above strain was applied and measurement was impossible, it was described as "-" in the table.

[Test Example 8] (Evaluation of blister resistance)
The constituents obtained in the examples and comparative examples were left standing for 24 hours at normal pressure, 23° C. and 50% RH, and used as samples. The obtained sample was stored for 72 hours under high temperature and high humidity conditions of 85° C. and 85% RH. Then, the state at the interface between the adhesive layer after curing and the adherend (cover material, glass plate) was visually confirmed, and the blister resistance was evaluated according to the following criteria. The results are shown in Table 2.
〇…There were no air bubbles or floating/peeling.
×...Bubbles and floating/peeling occurred.

[Test Example 9] (Measurement of warpage)
The constituents obtained in the examples and comparative examples were left standing for 24 hours at normal pressure, 23° C. and 50% RH, and used as samples. The obtained sample was stored for 72 hours under a high temperature condition of 105° C. and dry (durability test). Then, the sample was placed on a horizontal table with the cover material side facing up, and left at normal pressure, 23° C., and 50% RH for 24 hours.

After that, the amount of warp (distance between the corner and the base) of each corner (4 points) of the sample from the base was measured, and the amount of warp of each corner was totaled. Based on the result, the evaluation was performed as follows. The results are shown in Table 2.
⊚: Total warpage amount is 16 mm or less ○: Total warpage amount is more than 16 mm, 19 mm or less Δ: Total warpage amount is more than 19 mm, 24 mm or less ×: Total warpage amount is more than 24 mm In addition, according to the above durability test, Those that were lifted or peeled off at the interface between the pressure-sensitive adhesive layer and the adherend after curing were evaluated as x regardless of the amount of warpage.

As can be seen from Table 2, the cured pressure-sensitive adhesive layer formed using the optical pressure-sensitive adhesive sheets obtained in Examples can suppress the occurrence of warpage and is also excellent in blister resistance. It was

The optical pressure-sensitive adhesive sheet of the present invention can be suitably used, for example, for bonding a protective panel made of a plastic plate containing an ultraviolet absorber to a display body constituent member in a display body of a car navigation system.

DESCRIPTION OF SYMBOLS 1... Optical pressure-sensitive adhesive sheet 11... Active energy ray-curable pressure-sensitive adhesive layer 12a, 12b... Release sheet 2... Structure 11'... Pressure-sensitive adhesive layer (cured pressure-sensitive adhesive layer)
21... First display member component (ultraviolet shielding member)
22...Second display member constituting member 3...Printing layer

Claims (8)

One display member,
Other display member,
A structure comprising a pressure-sensitive adhesive layer for laminating the one display member constituting member and the other display member constituting member to each other,
At least one of the one display member constituting member and the other display member constituting member is an ultraviolet shielding member having an ultraviolet shielding property,
The one display member constituting member and the other display member constituting member are made of materials having different linear expansion coefficients,
One of the one display member forming member and the other display member forming member is a plastic plate,
The other of the one display member forming member and the other display member forming member is a member having a linear expansion coefficient equivalent to that of a glass plate or a glass plate,
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contains a crosslinked structure in which an acrylic acid ester polymer is crosslinked, and a cured product of an active energy ray-curable component,
The relative adhesive constituting the adhesive layer, continuously applied strain of 10% by thus torsional shear JIS K7244-1, the relaxation modulus which is measured from the straining after 10 minutes, 0.1 kPa or more, 5.5 kPa or less,
The composition has a gel fraction of the adhesive of 64% or more and 90% or less. The ultraviolet ray shielding member has a light transmittance of 20% or less at a wavelength of 360 nm, a light transmittance of 10% or more at a wavelength of 390 nm, and a light transmittance of 390 nm is more than a light transmittance of 360 nm. The structure of claim 1 , wherein the structure is large. Method for producing a structure comprising one display member constituting member, another display member constituting member, and a cured adhesive layer for bonding the one display member constituting member and the other display member constituting member to each other And
At least one of the one display member constituting member and the other display member constituting member is an ultraviolet shielding member having an ultraviolet shielding property,
The one display member constituting member and the other display member constituting member are made of materials having different linear expansion coefficients,
One of the one display member forming member and the other display member forming member is a plastic plate,
The other of the one display member forming member and the other display member forming member is a member having a linear expansion coefficient equivalent to that of a glass plate or a glass plate,
Through a pressure-sensitive adhesive layer made of an active energy ray-curable pressure-sensitive adhesive, a step of producing a laminate formed by bonding the one display body constituent member and the other display body constituent member,
With respect to the pressure-sensitive adhesive layer of the laminate, irradiating with active energy rays through the ultraviolet shielding member, comprising a step of curing the pressure-sensitive adhesive layer to a cured pressure-sensitive adhesive layer,
The post-curing pressure-sensitive adhesive layer constituting the post-curing pressure-sensitive adhesive layer is continuously subjected to 10% strain due to torsional shearing according to JIS K7244-1, and the relaxation elastic modulus measured 10 minutes after the straining is 0. 1 kPa or more and 5.5 kPa or less,
The gel fraction of the pressure-sensitive adhesive after curing is 64% or more and 90% or less
A method of manufacturing a structure, comprising: Display body comprising the construction according to claim 1 or 2. An optical pressure-sensitive adhesive sheet having an active energy ray-curable pressure-sensitive adhesive layer made of an active energy ray-curable pressure-sensitive adhesive for laminating one display-member constituting member and another display-member constituting member ,
One of the one display member forming member and the other display member forming member is a plastic plate,
The other of the one display member forming member and the other display member forming member is a member having a linear expansion coefficient equivalent to that of a glass plate or a glass plate,
The active energy ray-curable adhesive is
A (meth)acrylic acid ester polymer (A) containing 1% by mass or more and 15% by mass or less of a monomer having a hydroxyl group in the molecule as a monomer constituting the polymer;
A cross-linking agent (B),
An active energy ray-curable component (C),
Obtained from a pressure-sensitive adhesive composition containing a photopolymerization initiator (D) having an absorbance of 0.3 or more at a wavelength of 390 nm in an acetonitrile solution having a concentration of 0.1% by mass,
A crosslinked structure in which the (meth)acrylic acid ester polymer (A) is crosslinked with each other via the crosslinking agent (B), the unreacted active energy ray-curable component (C) and the photopolymerization initiator. (D) and contains,
With respect to the pressure-sensitive adhesive layer, through a plastic plate having a light transmittance of less than 1% at a wavelength of 360 nm and a light transmittance of 54% at a wavelength of 390 nm, an illuminance of 200 mW/cm ² and a light amount of 1000 mJ/cm were measured by a high pressure mercury lamp. The increase in the gel fraction of the active energy ray-curable pressure-sensitive adhesive accompanying the curing when irradiated with the active energy ray ² is 10 points or more,
An optical pressure-sensitive adhesive sheet, wherein the active energy ray-curable pressure-sensitive adhesive has a gel fraction of 40% or more and 60% or less. The content of the active energy ray-curable component (C) in the adhesive composition is 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A). The optical pressure-sensitive adhesive sheet according to claim 5 , wherein Two release sheets,
The optical pressure-sensitive adhesive sheet according to claim 5 or 6 , further comprising: the active energy ray-curable pressure-sensitive adhesive layer sandwiched between the release sheets so as to contact the release surfaces of the two release sheets. .. One display body constituent member, at least one of which is the ultraviolet-shielding member, and another through the active energy ray-curable pressure-sensitive adhesive layer of the optical pressure-sensitive adhesive sheet according to any one of claims 5 to 7. A laminated body is prepared by laminating the display body constituent members,
For the pressure-sensitive adhesive layer of the laminate, active energy rays are radiated through the ultraviolet shielding member to cure the pressure-sensitive adhesive layer to obtain a cured pressure-sensitive adhesive layer. Method.

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