TW201439267A - Active-energy-ray-curable adhesive, adhesive sheet, and laminate - Google Patents

Abstract

This invention provides an active-energy-ray-curable adhesive with an excellent unevenness followability for printing layers and an excellent durability, an adhesive sheet, and a laminate. To address the above-mentioned subject, provided is an active-energy-ray-curable adhesive. When the active-energy-ray-curable adhesive is processed to form an adhesive layer with a thickness of 600 micron, the press stress on the adhesive layer surface in a 5mm*5mm area at a rate of 6mm/min pressing to a depth of 500 micron for 10 seconds is 4.0-7.0N before irradiating active energy ray onto the adhesive layer and 7.0-15.0N after irradiating active energy ray onto the adhesive layer, wherein the ratio of the press stress after irradiating active energy ray onto the adhesive layer to the press stress before irradiating active energy ray onto the adhesive layer is 1.30-2.50.

Description

Active energy ray-curable adhesive, adhesive sheet and laminate

The present invention relates to an active energy ray-curable adhesive, an adhesive sheet having an active energy ray-curable adhesive layer, and a laminate obtained by using the active energy ray-curable adhesive.

In recent years, various mobile electronic devices such as mobile phones and tablet terminals have displays using display modules such as liquid crystal devices, light emitting diodes (LED devices), and organic plating cold light (organic EL) devices.

In such a display, generally, a protective panel is provided on the surface side of the display module. When the protection panel and the display module are deformed, a gap is formed when the protection panel is deformed due to an external force, so that the deformed protection panel does not touch the display module.

However, the void as described above, that is, the air layer, if present, has a difference in refractive index between the protective panel and the air layer, and a reflection loss of light caused by a difference in refractive index between the air layer and the display module is large, and the image quality of the display is lowered. problem.

Therefore, research has proposed to improve the image quality of the display by filling the gap between the protective panel and the display module with the adhesive layer. However, the display module side of the protective panel may have a frame-shaped printed layer as the unevenness. If the adhesive layer does not follow the unevenness, the adhesive layer floats from the vicinity of the unevenness, whereby light reflection loss occurs. Therefore, the adhesive layer is required to have irregularity follow-up.

In order to solve the above problem, Patent Document 1 describes that the shear storage modulus (G') at 25 ° C and 1 Hz is 1.0 × 10 ⁵ Pa or less as an adhesive layer filling the gap between the protective panel and the display module. And, the gel fraction is 40% or more of the adhesive layer.

Further, Patent Document 2 describes a transparent double-sided adhesive sheet for ultraviolet bridging which is composed of an ultraviolet bridge and retains the hardness (C2 ASKER hardness) (A) in the range of 10 ≦ (a) < 50 while retaining the ultraviolet ray reactivity. Further, the indentation hardness (C2 ASKER hardness) (B) after the second curing by ultraviolet irradiation is in the range of 33 ≦ (B) ≦ 80.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-97070

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2012-184423

In Patent Document 1, it is intended to improve the storage performance of the adhesive layer at a normal temperature to improve the unevenness. However, if the storage modulus at normal temperature is lowered as described above, the storage modulus at a high temperature is excessively lowered, and problems occur under endurance conditions. For example, after the high-temperature and high-humidity conditions are carried out, when returning to normal temperature and normal humidity, there is a problem that bubbles are generated in the vicinity of the unevenness.

Further, in Patent Document 2, the ratio of the press-fitting stress of the adhesive layer to the adhesive stress of the adhesive layer after curing is not sufficiently large, and the unevenness and durability are not sufficient. coexist. In addition, Patent Document 2 The bump followability and the foaming reliability (durability) were also evaluated. However, the tracking followability in Patent Document 2 is such that the followability of a ball called a glass bead is easier to follow than the unevenness of the corner such as a printed layer, and the durability evaluation is also correct. Durability test conducted in a very short time.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an active energy ray-curable adhesive, an adhesive sheet, and a laminate which are excellent in followability of irregularities such as a printed layer and excellent in durability. body.

In order to achieve the above object, the present invention provides an active energy ray-curable adhesive characterized in that it is an active energy ray-curable adhesive which is cured by irradiation of an active energy ray, and the active energy ray is used. When the curable adhesive is formed into an adhesive layer having a thickness of 600 μm, the surface of the adhesive layer is pressed at a speed of 6 mm/min to a depth of 500 μm for 10 seconds on an area of 5 mm × 5 mm. The press-in stress is 4.0 N to 7.0 N before the application of the active energy ray to the adhesive layer, and 7.0 N to 15.0 N after the active energy ray is applied to the adhesive layer. The ratio of the indentation stress after the active energy ray is applied to the adhesive layer to the indentation stress before the application of the active energy ray to the adhesive layer is 1.30 to 2.50 (Invention 1).

In the active energy ray-curable adhesive according to the invention of the first aspect of the invention, the indentation stress before the active energy ray irradiation and the indentation stress after the irradiation of the active energy ray and the ratio thereof are defined as described above. In the case where the active energy ray is irradiated, the unevenness is excellent in follow-up property, and even after being exposed to high-temperature and high-humidity conditions after the irradiation of the active energy ray, the irregularity can be maintained, air bubbles are not generated, and the durability is excellent.

In the above invention (Invention 1), the storage modulus of the active energy ray-curable adhesive at 23 ° C is preferably 0.01 MPa to 0.2 MPa before the active energy ray-curable adhesive is irradiated with the active energy ray. Preferably, the active energy ray-curable adhesive is irradiated with an active energy ray of 0.02 MPa to 0.5 MPa (Invention 2).

In the above invention (Invention 2), the storage modulus at 23 ° C after the active energy ray is applied to the adhesive layer, and the storage mode at 23 ° C before the application of the active energy ray to the adhesive layer The ratio of the amounts is preferably from 1.1 to 2.5 (Invention 3).

In the above invention (Invention 1 to Invention 3), the storage modulus of the active energy ray-curable adhesive at 85 ° C is preferably 0.01 MPa before the active energy ray-curable adhesive is irradiated with the active energy ray. ~0.1 MPa is preferably 0.02 MPa to 0.2 MPa after the active energy ray-curable adhesive is applied to the active energy ray (Invention 4).

In the above invention (Invention 4), the storage modulus at 85 ° C after the active energy ray is applied to the adhesive layer, and the storage mode at 85 ° C before the application of the active energy ray to the adhesive layer The ratio of the amounts is preferably from 1.1 to 3.5 (Invention 5).

Secondly, the present invention provides a bonding sheet comprising two release sheets and an adhesive layer for holding the release sheet in contact with the release faces of the two release sheets, the adhesive The layer is composed of the above active energy ray-curable adhesive (Invention 1 to Invention 5) (Invention 6).

Thirdly, the present invention provides a laminated body comprising: two rigid plates and an adhesive layer for bonding the two rigid plates to each other, The adhesive layer is cured by irradiating the active energy ray-curable adhesive (Inventions 1 to 5) with an active energy ray (Invention 7).

In the above invention (Invention 7), at least one of the hard plates preferably has irregularities on the surface on the side of the adhesive layer (Invention 8).

In the above invention (Invention 8), it is preferable that the unevenness is due to the unevenness of the printed layer (Invention 9).

In the above invention (Invention 7 to Invention 9), at least one of the hard plates may include a polarizing plate (Invention 10).

Further, in the above invention (Invention 7 to Invention 9), one of the two rigid plates is a display module or a part thereof, and the other of the two rigid plates is on the surface on the side of the adhesive layer. A protective plate having a frame-like unevenness is also possible (Invention 11).

In the above invention (Invention 7 to Invention 11), the total light transmittance of the adhesive layer is preferably 80% or more (Invention 12).

The active energy ray-curable adhesive of the present invention and the adhesive layer of the adhesive sheet according to the present invention are excellent in the follow-up property before the active energy ray irradiation, and are excellent in durability after the irradiation with the active energy ray. In the laminate obtained by using such an active energy ray-curable adhesive, even if the adhesive layer has irregularities on the side of the adhesive layer, the adhesive layer follows the unevenness, so that floating or bubbles do not occur near the unevenness. Wait. In addition, even if the adhesive layer of the laminated body is placed under high temperature and high humidity conditions, the adhesion tracking property can be maintained, air bubbles are not generated, and the durability is excellent.

1‧‧‧bonding piece

11‧‧‧Adhesive layer

12a, 12b‧‧‧ peeling film

2‧‧‧Laminated body

21‧‧‧1st hard board

22‧‧‧2nd hard board

3‧‧‧Printing layer

Fig. 1 is a cross-sectional view showing an adhesive sheet according to an embodiment of the present invention.

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

Hereinafter, embodiments of the present invention will be described.

[Active Energy Line Curing Adhesive]

Physical property

The active energy ray-curable adhesive according to the embodiment has the following physical properties. In other words, when the active energy ray-curable adhesive according to the present embodiment is an adhesive layer having a thickness of 600 μm, the surface of the adhesive layer is 6 mm/min in an area of 5 mm × 5 mm. The speed is up to 500μm and the indentation stress after pressing for 10 seconds is 4.0N~7.0N before the active energy line is applied to the adhesive layer. After the active energy ray is applied to the adhesive layer, it is 7.0N~15.0N.

Further, in the present specification, the press-in stress is measured by setting the size of the adhesive layer to 50 mm in the longitudinal direction, 50 mm in the lateral direction, and 600 μm in the thickness, and the indented member is made of the tantalum wafer over 5 mm in the longitudinal direction, 5 mm in the lateral direction, and 500 μm in the thickness. The size was measured at a temperature of 23 ° C and a relative humidity of 50% RH using a universal tensile compression tester (Instron Model "Instron Model 5 Model" was used in the test example).

When the indentation stress before the irradiation of the active energy ray is 4.0 N to 7.0 N, the active energy ray-curable adhesive is excellent in unevenness at the time of attachment before the irradiation of the active energy ray. Therefore, even if the adherend has irregularities, the active energy ray-curable adhesive adheres to the irregularities, so that there is no floating or bubbles or the like in the vicinity of the unevenness. If the indentation stress before the active energy ray irradiation is less than 4.0N, the cutting is performed, etc. The workability is lowered, or the durability after the active energy ray irradiation is insufficient, and if the press-in stress before the active energy ray irradiation exceeds 7.0 N, the unevenness followability at the time of attachment is lowered. The indentation stress before the irradiation of the active energy ray is preferably 4.4 N to 6.7 N, and particularly preferably 4.6 N to 6.5 N.

On the other hand, the active energy ray-curable adhesive after the irradiation of the active energy ray is 7.0 N to 15.0 N, and the active energy ray-curable adhesive is placed in a high-temperature and high-humidity condition (for example, 85 ° C after the active energy ray irradiation). In the case of 85% RH and 240 hours), the tracking followability can be maintained, bubbles are not generated, and the durability is excellent. When the indentation stress after the active energy ray irradiation is less than 7.0 N, the durability is lowered, and if the indentation stress after the active energy ray irradiation exceeds 15.0 N, the unevenness followability cannot be maintained under high temperature and high humidity conditions. The indentation stress after the irradiation of the active energy ray is preferably 7.2 N to 11.0 N, and particularly preferably 7.4 N to 9.5 N.

Further, the ratio of the indentation stress after the irradiation of the active energy ray to the indentation stress before the irradiation of the active energy ray (the indentation stress after the active energy ray irradiation/the indentation stress before the irradiation of the active energy ray) is 1.30. ~ 2.50, preferably 1.35 to 2.20, particularly preferably 1.37 to 1.90. When the ratio of the press-in stress is in the above range, the unevenness followability before the irradiation of the active energy ray and the durability after the irradiation of the active energy ray can be maintained in a good balance.

The active energy ray-curable adhesive according to the present embodiment further preferably has the following physical properties. That is, the storage modulus of the active energy ray-curable adhesive at 23 ° C before the active energy ray irradiation is preferably 0.01 MPa to 0.2 MPa, particularly preferably 0.04 MPa to 0.15 MPa, and more preferably 0.07 MPa to 0.1 MPa. Further, the storage modulus of the active energy ray-curable adhesive at 85 ° C before the active energy ray irradiation is preferably 0.01 MPa to 0.1 MPa, and particularly preferably 0.01 MPa to 0.06 MPa, and more preferably 0.02 MPa to 0.04 MPa. In addition, the storage modulus in this specification is a value measured by the torsion shear method based on JIS K7244-6 at the measurement frequency of 1 Hz. The active energy ray-curable adhesive agent before the active energy ray irradiation has the storage modulus as described above, and the unevenness followability is further improved.

On the other hand, the storage modulus of the active energy ray-curable adhesive at 23 ° C after the active energy ray irradiation is preferably 0.02 MPa to 0.5 MPa, particularly preferably 0.05 MPa to 0.3 MPa, and further preferably 0.09 MPa to 0.2. MPa. Further, the storage modulus of the active energy ray-curable adhesive at 85 ° C after the active energy ray irradiation is preferably 0.02 MPa to 0.2 MPa, particularly preferably 0.02 MPa to 0.1 MPa, and more preferably 0.03 MPa to 0.05 MPa. The active energy ray-curable adhesive after the irradiation of the active energy ray has a storage modulus as described above, and the durability is further improved.

In addition, the storage modulus at 23 ° C after active energy ray irradiation is compared with the storage modulus at 23 ° C before the active energy ray irradiation (storage modulus / active energy ray after active energy ray irradiation) The storage modulus before irradiation is preferably from 1.1 to 2.5, particularly preferably from 1.2 to 2.0, still more preferably from 1.3 to 1.7.

As described above, after the active energy ray-curable adhesive (after curing), the storage modulus of the active energy ray-curable adhesive at 23 ° C increases, and the cured active energy ray-curable adhesive has excellent durability.

In addition, the storage modulus at 85 ° C after active energy ray irradiation is compared with the storage modulus at 85 ° C before the active energy ray irradiation (storage modulus / active energy ray after active energy ray irradiation) The storage modulus before irradiation is preferably from 1.1 to 3.5, particularly preferably from 1.3 to 2.5, still more preferably from 1.4 to 2.0.

As described above, after the active energy ray irradiation (after curing), the storage modulus of the active energy ray-curable adhesive at 85 ° C rises, and the cured active energy ray-curable adhesive, especially at high temperatures Excellent durability.

If the ratio of the above storage modulus at 23 ° C or 85 ° C is less than 1.1, the effect of improving the durability as described above may not be obtained. On the other hand, if the ratio of the storage modulus at 23 ° C exceeds 2.5, or the ratio of the storage modulus at 85 ° C exceeds 3.5, the adhesion of the cured active energy ray-curable adhesive decreases. It may not be possible to obtain sufficient durability. In addition, if the ratio of the storage modulus at 23 ° C exceeds 2.5, or the ratio of the storage modulus at 85 ° C exceeds 3.5, the three-dimensional network structure formed by the active energy ray solidification becomes too dense, presumably The moisture leakage in the adhesive is deteriorated, and the wet heat whitening resistance is lowered.

2. Materials

The active energy ray-curable adhesive according to the present embodiment (hereinafter referred to simply as "adhesive") has any of the above physical properties and has desired adhesive properties and adhesion. Although the material composition may be sufficient, it is preferable to contain a (meth) acrylate copolymer having a weight average molecular weight of 200,000 to 900,000 as a monomer unit constituting the polymer and containing 5% by mass to 20% by mass of (meth)acrylic acid. The adhesive composition of the active material (A), the active energy ray-curable component (B), and the bridging agent (C) (hereinafter referred to as "adhesive composition P") is thermally bridged. The active energy ray-curable adhesive agent obtained by thermally bridging the adhesive composition P is likely to have sufficient physical properties as described above, and exhibits excellent adhesion and adhesion to a hard board or the like. In the present specification, the above (meth)acrylic acid means both of acrylic acid and methacrylic acid. The same is true for other similar terms.

The active energy ray-curable adhesive composed of the adhesive composition P is thermally bridged, and specifically, the (meth) acrylate copolymer (A) is bridged by the bridging agent (C). On the other hand, the active energy ray-curable component (B) is not cured, and is present in the active energy ray-curable adhesive in a state of being bonded to the adhesive composition P. The active energy ray-curable component (B) is polymerized and cured when the active energy ray-curable adhesive is irradiated with an active energy ray at the time of use (when the adherend is bonded).

(1) (meth) acrylate copolymer (A)

The (meth) acrylate copolymer (A) preferably contains 5% by mass to 20% by mass of (meth)acrylic acid as the monomer unit constituting the polymer, and particularly preferably contains 7% by mass to 15% by mass, further It is preferably contained in an amount of 8 mass% to 12 mass%. When the content of (meth)acrylic acid is in the above range, the bridging structure formed by the (meth) acrylate copolymer (A) and the bridging agent (C) is good, and the adhesive has excellent durability. Further, the content of (meth)acrylic acid is in the above range, and it is presumed that the cohesive force in the appearance of the adhesive can be improved, and the weight average molecular weight and bridging density of the (meth) acrylate copolymer (A) are suppressed. At the same time, since the stress relaxation property is improved, the adhesive has excellent unevenness in tracking. Further, the adhesive composition P containing the (meth)acrylic acid ester copolymer (A) having a content of (meth)acrylic acid in the above range, the obtained adhesive is cured after the adhesive is cured. After high-temperature and high-humidity conditions (for example, leaving at 85 ° C and 85% RH for 240 hours), whitening at the time of returning to normal temperature and normal humidity is suppressed, that is, it is excellent in wet heat and whitening resistance. When the (meth) acrylate copolymer (A) contains the above amount of (meth)acrylic acid as a monomer unit, a certain amount of carboxyl groups remain in the obtained (thermally bridged) adhesive. The carboxyl group is a hydrophilic functional group, and this hydrophilic functional group If it is present in the binder in a quantitative amount, it is presumed that even after the adhesive is irradiated with the active energy ray and placed under high temperature and high humidity conditions, the moisture immersed in the adhesive under high temperature and high humidity conditions is restored to normal temperature and humidity. At the time, it is also easy to be detached from the adhesive, and as a result, whitening of the adhesive is suppressed.

In the (meth) acrylate copolymer (A), when the content of the (meth)acrylic acid as the monomer unit is less than 5% by mass, the active energy ray-curable adhesive, particularly the wet heat-resistant whitening property Reduced situation. On the other hand, when the content of (meth)acrylic acid exceeds 20% by mass, the coating property of the adhesive composition P may be deteriorated.

The (meth) acrylate copolymer (A) is preferably a (meth)acrylic acid alkyl ester having an alkyl group and having 1 to 20 carbon atoms as a monomer unit constituting the polymer, and particularly preferably as a main component. Contained as a component. Thereby, the obtained adhesive can exhibit excellent adhesion.

Examples of the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylic acid. Base ester, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylate Octyl ester, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, (methyl) ) Acrylic stearyl group and the like. Among them, from the viewpoint of further improving the adhesion, a (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferable, and methyl (meth)acrylate and n-butyl (meth)acrylate are particularly preferable. 2-ethylhexyl (meth)acrylate. Further, these may be used alone or in combination of two or more.

The (meth) acrylate copolymer (A), as a monomer unit constituting the polymer, preferably contains 40% by mass to 95% by mass of an alkyl group having 1 to 20 carbon atoms of (meth)acrylic acid alkyl group. The ester is particularly preferably contained in an amount of from 80% by mass to 93% by mass, and more preferably from 88% by mass to 92% by mass.

The (meth) acrylate copolymer (A) may contain other monomers as a monomer unit constituting the polymer, as needed. As another monomer, it is preferable not to contain a monomer having a reactive functional group, even if it does not interfere with the reaction of (meth)acrylic acid. Examples of such other monomers include (meth)acrylic acid alkoxyalkyl esters such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, and (methyl). a non-branching acrylamide such as an aliphatic ring-containing (meth) acrylate such as cyclohexyl group, acrylamide or methacrylamide, or N,N-dimethylamino (meth)acrylate A (meth) acrylate having a non-branching tertiary amino group such as an ethyl group or an N,N-dimethylaminopropyl group (meth)acrylate, vinyl acetate, styrene or the like. These may be used alone or in combination of two or more.

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

The weight average molecular weight of the (meth) acrylate copolymer (A) is preferably 200,000 to 900,000, particularly preferably 250,000 to 700,000, and more preferably 300,000 to 500,000. The weight average molecular weight in the present specification is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

The weight average molecular weight of the main component (meth) acrylate copolymer (A) of the adhesive composition P is small as described above, and the adhesive obtained by thermally bridging the adhesive composition P is chaotic Excellent in sex. (meth) acrylate copolymer When the weight average molecular weight of (A) exceeds 900,000, the unevenness followability may be lowered. On the other hand, when the weight average molecular weight of the (meth) acrylate copolymer (A) is less than 200,000, the durability of the adhesive after the active energy ray irradiation may be lowered.

Further, in the adhesive composition P, the (meth) acrylate copolymer (A) may be used alone or in combination of two or more.

(2) Active energy ray curable component (B)

The adhesive composition P is an active energy ray-curable adhesive which is formed by the active energy ray-curable component (B), and is excellent in unevenness and durability.

The active energy ray-curable component (B) is not particularly limited as long as it does not inhibit the effects of the present invention and is cured by irradiation with an active energy ray, and may be any of a monomer oligomer or a polymer. It can also be a mixture of them. Among them, a polyfunctional acrylate monomer having a molecular weight of less than 1,000 which is excellent in compatibility with the (meth) acrylate copolymer (A) or the like can be preferably used.

Examples of the polyfunctional acrylate monomer having a molecular weight of less than 1,000 include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopenta-2. Alcohol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(methyl) Acrylate, dicyclopentyl di(meth) acrylate, caprolactone modified dicyclopentenyl di(meth) acrylate, ethylene oxide modified di(meth) acrylate, di Bifunctional type such as acryloxyethyl)isocyanate or allylated cyclohexyl di(meth)acrylate; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate Propionic acid modified dipentaerythritol Alcohol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tris(propyleneoxyethyl)isocyanate, ε-hexyl a trifunctional type such as a lactone-modified tris(2-(meth)acryloxyethyl)isocyanate; a tetrafunctional type such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; A 5-functional type such as a propionic acid-modified dipentaerythritol penta(meth)acrylate; a penta-functional type such as dipentaerythritol hexa(meth)acrylate or caprolactone-modified dipentaerythritol hexa(meth)acrylate; These may be used alone or in combination of two or more.

As the active energy ray-curable component (B), an active energy ray-curable acrylate-based oligomer can also be used. The acrylate oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such an acrylate-based oligomer include polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polybutadiene acrylates, anthrone acrylates, and the like.

Here, as the polyester acrylate oligomer, for example, a hydroxyl group or a polyester of a polyester oligomer having a hydroxyl group at both terminals obtained by polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol can be used by using (meth)acrylic acid. Alternatively, it may be obtained by esterifying a hydroxyl group at the terminal of the oligomer obtained by adding an alkylene oxide to a polyvalent carboxylic acid with (meth)acrylic acid. The epoxy acrylate oligomer can be, for example, reacted and esterified on a bisphenol type epoxy resin having a relatively low molecular weight and an oxirane ring of a novolac type epoxy resin. And get it. Further, a carboxy-modified epoxy acrylate oligomer obtained by partially modifying the epoxy acrylate oligomer with a dibasic carboxylic acid anhydride can also be used. a urethane acrylate oligomer, for example, by using (meth) propylene The acid is obtained by esterifying a polyurethane polyol and a urethane oligomer obtained by a reaction of a polyester polyol and a polyisocyanate. The polyol acrylate oligomer can be obtained by esterifying a hydroxyl group of a polyether polyol with (meth)acrylic acid.

The weight average molecular weight of the acrylate oligomer is preferably 50,000 or less, particularly preferably 500 to 50,000, and still more preferably 3,000 to 40,000. These acrylate oligomers may be used alone or in combination of two or more.

Further, as the active energy ray-curable component (B), an additive acrylate-based polymer obtained by introducing a group having a (meth) acrylonitrile group into a side chain can also be used. Such an additive acrylate-based polymer can have a (meth) acrylonitrile group and a bridging functional group by using a copolymer of a (meth) acrylate and a monomer having a bridging functional group in the molecule. The compound of the reactive group is obtained by reacting a part of the bridging functional group of the copolymer.

The (meth) acrylate is preferably an alkyl (meth) acrylate having an alkyl group and having 1 to 20 carbon atoms, and examples thereof include methyl (meth)acrylate and ethyl (meth)acrylate. Base ester, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (methyl) ) 2-ethylhexyl acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, ( Cetylmethyl methacrylate, stearyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

The monomer having a bridging functional group in the molecule preferably contains at least one selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a guanamine group as a functional group. Examples of the monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth)acrylic acid 2. Hydroxyalkyl (meth)acrylate such as -hydroxybutyl ester, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate; N-methylol acrylamide Acrylamides; monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, (meth)acrylic acid Monoalkylaminoalkyl (meth)acrylate such as monoethylaminopropyl ester; ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid or citraconic acid Wait. These monomers may be used singly or in combination of two or more.

As the compound having a group reactive with a (meth)acryl fluorenyl group and a bridging functional group, for example, 2-methylpropenyloxyethyl isocyanate or 2-(0-[1] methacrylate can be preferably used. '-Methylpropylenepropaneamino]carboxyamino)ethyl, 2-[(3,5-dimethylpyridyl)carbonylamino]ethyl methacrylate, 1,1-(bispropenyloxymethyl) Ethyl isocyanate, 2-propenyloxyethyl isocyanate, 2-propenyloxyethyl succinate, 2-propenyl oxiranyl hexahydrophthalate, ω-carboxy-polycaprolactone Acrylate, monohydroxyethyl phthalate, 2-hydroxy-3-phenoxypropyl acrylate, and the like. These compounds may be used singly or in combination of two or more.

The weight average molecular weight of the above-mentioned additive acrylate polymer is preferably from 50,000 to 900,000, particularly preferably from about 100,000 to 500,000.

The active energy ray-curable component (B) may be selected from the above-mentioned polyfunctional acrylate monomer, acrylate oligomer, and additive acrylate polymer, or two or more types may be used. Use together, It can also be used in combination with active energy ray-curable components other than these.

The content of the active energy ray-curable component (B) in the adhesive composition P is preferably from 1 part by mass to 10 parts by mass per 100 parts by mass of the (meth) acrylate copolymer (A), and particularly preferably It is 2 parts by mass to 8 parts by mass, and more preferably 3 parts by mass to 7 parts by mass. When the content of the active energy ray-curable component (B) is less than 1 part by mass, the durability of the adhesive after the active energy ray irradiation may be lowered. When the content of the active energy ray-curable component (B) exceeds 10 parts by mass, the wet heat whitening resistance of the adhesive after the active energy ray irradiation may be deteriorated.

(3) bridging agent (C)

The adhesive composition P is bridged with a bridging agent (C) to form a three-dimensional network structure, thereby improving the cohesive force of the obtained adhesive. In addition, the adhesive may be imparted with durability after irradiation with the active energy ray.

The bridging agent (C) is a reactive bridging agent which is reactive with respect to the reactive functional group (carboxyl group of (meth)acrylic acid of a monomer unit) which the (meth)acrylate copolymer (A) has. Examples thereof include an isocyanate bridging agent, an epoxy bridging agent, an amine bridging agent, a melamine bridging agent, an aziridine bridging agent, an anthraquinone bridging agent, an aldehyde bridging agent, an oxalate-type bridging agent, Metal alkoxide bridging agents, metal chelate bridging agents, metal salt bridging agents, ammonium salt bridging agents, and the like. The bridging agent (C) may be used alone or in combination of two or more.

Among them, at least one selected from the group consisting of an epoxy type bridging agent and an isocyanate bridging agent having excellent reactivity with a carboxyl group is used as a bridging agent (C). Preferably, it is particularly preferred to use an epoxy type bridging agent. An adhesive using an epoxy-based bridging agent is excellent in heat resistance and is not easily yellowed, and is suitable for optical use.

Examples of the epoxy-based bridging agent include 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane and N,N,N',N'-tetraglycidyl group. Toluene diamine, ethylene glycol diglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, diglycidylamine, and the like.

The isocyanate bridging agent is a bridging agent containing at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as methylphenyl diisocyanate, diphenylmethane diisocyanate and xylene diisocyanate, and aliphatic polyisocyanates such as hexamethylene diisocyanate and isophor. Examples of the alicyclic polyisocyanate such as keto diisocyanate and hydrogenated diphenylmethane diisocyanate, and the biuret or isocyanate of these, and further examples thereof include ethylene glycol, propylene glycol, neopentyl glycol, and trimethylolpropane. An additive such as castor oil or the like which is a reactant containing a low molecular weight active hydrogen compound.

The content of the bridging agent (C) in the adhesive composition P is preferably 0.001 parts by mass to 2 parts by mass, particularly preferably 0.01 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer (A). 1 part by mass, more preferably 0.02 part by mass to 0.3 part by mass. When the content of the bridging agent (C) is 0.001 part by mass or more, the adhesive after the active energy ray irradiation can provide an effect of improving durability. When the content of the bridging agent (C) exceeds 2 parts by mass, the degree of bridging is excessive, and the unevenness of the obtained adhesive may be lowered. Further, the carboxyl group of the (meth) acrylate copolymer (A) is largely reacted with the bridging agent (C), and the amount of the carboxyl group remaining in the binder is small, and the above-mentioned moist heat whitening property may be lowered.

(4) Photopolymerization initiator (D)

When the ultraviolet ray is used as the active energy ray to which the active energy ray-curable adhesive is applied, the adhesive composition P further preferably contains a photopolymerization initiator (D). By containing the photopolymerization initiator (D) as described above, the active energy ray-curable component (B) can be effectively cured, and the polymerization curing time and the irradiation amount of the active energy ray can be reduced.

Examples of such a photopolymerization initiator (D) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin n-butyl ether. Benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylbenzene Ethyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl] -2-Merlin-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone 4,4'-Diethylaminobenzophenone, dichlorobenzophenone, 2-methyloxime, 2-ethylhydrazine, 2-tert-butylhydrazine, 2-aminopurine, 2 -methyl ketoxime, 2-ethyl ketoxime, 2-chloroseptone, 2,4-dimethyl ketoxime, 2,4-diethyl ketoxime, benzyl dimethyl condensate Ketone, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2 , 4,6-trimethylbenzimidyl-diphenyl-phosphine oxide, and the like. These may be used alone or in combination of two or more.

The photopolymerization initiator (D) is preferably used in an amount of from 2 parts by mass to 15 parts by mass, particularly preferably from 4 parts by mass to 12 parts by mass, per 100 parts by mass of the active energy ray-curable component (B).

(5) Various additives

The adhesive composition P may be added with various additives commonly used in acrylic adhesives, such as a decane coupling agent, a charge preventing agent, an adhesion-imparting agent, an oxidation preventing agent, an ultraviolet absorber, and light stabilization, as needed. Agent, softener, filler, refractive index modifier, and the like.

The oxime coupling agent is preferably an organic ruthenium compound having at least one alkoxymethyl decane in the molecule, and is preferably compatible with the (meth) acrylate copolymer (A). Further, when the adhesive is used for optical use, it is preferably a light-transmitting decane coupling agent.

The decane coupling agent may, for example, be a polymerizable unsaturated group-containing oxime compound such as vinyl trimethoxy decane, vinyl triethoxy decane or methacryl methoxypropyl trimethoxy decane, or - an oxime compound having an epoxy structure such as glycidoxytrimethoxydecane or 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, 3-mercaptopropyltrimethoxydecane, 3 a mercapto group-containing hydrazine compound such as mercaptopropyltriethoxydecane or 3-mercaptopropylmethyldimethoxydecane, 3-aminopropyltrimethoxydecane, N-(2-aminoethyl)- An amino group-containing hydrazine compound such as 3-aminopropyltrimethoxydecane or N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, 3-chloropropyltrimethoxydecane, 3-isocyanate propyl triethoxy decane, or a mixture of at least one of these and methyl triethoxy decane, ethyl triethoxy decane, methyl trimethoxy decane, ethyl trimethoxy decane, etc. A condensate of an alkyl ruthenium compound or the like. These may be used alone or in combination of two or more.

The amount of the decane coupling agent to be added is preferably 0.01 parts by mass to 1.0 part by mass, and particularly preferably 0.05 parts by mass to 0.5 parts by mass, per 100 parts by mass of the (meth) acrylate copolymer (A).

(6) Manufacture of adhesive composition

The adhesive composition P can be obtained by producing the (meth) acrylate copolymer (A), the obtained (meth) acrylate copolymer (A), the active energy ray-curable component (B), and a bridging agent ( C) mixing is carried out, and at the same time, a photopolymerization initiator (D) and/or an additive is added as needed to manufacture.

The (meth) acrylate copolymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by a usual radical polymerization method. The polymerization of the (meth) acrylate copolymer (A) can be carried out by a solution polymerization method or the like using a polymerization initiator as needed. 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 thereof may be used in combination.

Examples of the polymerization initiator include an azo compound and an organic peroxide, and two or more kinds thereof can be used at the same time. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis(cyclohexane-1). - nitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), Dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanoshikimate), 2,2'-azobis(2-hydroxyl) Methylpropionitrile), 2,2'-azobis[2-(2-misoline-2-yl)propane], and the like.

Examples of the organic peroxide include benzamidine peroxide, t-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, and di-n-propyl peroxygen. Dicarbonate, bis(2-ethoxyethyl)peroxydicarbonate, tert-butyl peroxy neopentate, tert-butyl peroxypivalate, (3,5,5-trimethyl醯 )) peroxide, dipropylene peroxide, diethyl hydrazine peroxide Compounds, etc.

Further, in the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by mixing a chain shifting agent such as 2-mercaptoethanol.

After obtaining the (meth) acrylate copolymer (A), the active energy ray-curable component (B), the bridging agent (C), and, if necessary, are added to the solution of the (meth) acrylate copolymer (A). The polymerization initiator (D) and the additive are thoroughly mixed to obtain a tackifying composition P.

(7) Manufacture of active energy ray-curable adhesive

The active energy ray-curable adhesive according to the present embodiment is obtained by coating the above-mentioned adhesive composition P and then thermally bridging. The heat bridge of the adhesive composition P can be carried out by heat treatment. 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 from 50 ° C to 150 ° C, particularly preferably from 70 ° C to 120 ° C. Further, the heating time is preferably from 10 seconds to 10 minutes, particularly preferably from 50 seconds to 2 minutes. In particular, it is preferable to retain the ripening period of about 1 to 2 weeks at room temperature (for example, 23 ° C, 50% RH) after the heat treatment.

The bridging agent (C) is interposed by the above heat treatment (and aging), and the (meth) acrylate copolymer (A) is well bridged to obtain an active energy ray-curable adhesive. Further, in the active energy ray-curable adhesive, the active energy ray-curable component (B) exists in a state of being blended in the adhesive composition P.

The active energy ray-curable adhesive of the present embodiment described above is excellent in unevenness followability before irradiation with an active energy ray, and is excellent in durability after irradiation with an active energy ray. In particular, the adhesive composition P is thermally bridged. The obtained active energy ray-curable adhesive is also excellent in moist heat whitening resistance after irradiation with an active energy ray.

[bonding sheet]

As shown in Fig. 1, in the bonding sheet 1 of the present embodiment, the two release sheets 12a and 12b are sandwiched between the two release sheets 12a and 12b and the release surfaces of the two release sheets 12a and 12b. The adhesive layer 11 of 12b is composed. In addition, the peeling surface of the peeling sheet in this specification is the surface which has the peeling property in the peeling sheet, and the surface which carried out the peeling process, and the surface which shows the peeling-

Adhesive layer

The adhesive layer 11 in the adhesive sheet 1 is composed of the active energy ray-curable adhesive, exhibits adhesiveness before irradiation with an active energy ray, and cures after irradiation with an active energy ray to exhibit adhesiveness. The adhesive layer 11 is preferably formed by thermally bridging the adhesive composition P. At this time, the active energy ray-curable component (B) in the adhesive composition P is polymerized and cured by irradiation with an active energy ray.

The thickness of the adhesive layer 11 (value measured based on JIS K7130) is preferably 50 μm to 400 μm , particularly preferably 70 μm to 300 μm , and still more preferably 90 μm to 250 μm . Further, the adhesive layer 11 may be formed of a single layer or may be formed by laminating a plurality of layers.

When the thickness of the adhesive layer 11 is less than 50 μm , sufficient roughness follow-up may not be obtained, and if the thickness of the adhesive layer 11 exceeds 400 μm , the workability may be lowered.

2. Stripping sheet

As the release sheets 12a and 12b, for example, a polyethylene film can be used. Polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polynaphthalene dioxide Ethylene glycol ester film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene-(meth)acrylic copolymer film, ethylene-(meth)acrylic acid An ester copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film, or the like. In addition, bridging films of these can also be used. Further, these may be a laminated film.

It is preferable that the peeling surface of the peeling sheets 12a and 12b (particularly the surface which contact|connects the adhesive bond layer 11) is the peeling process. Examples of the release agent used for the release treatment include a release agent of an alkyd, an anthrone, a fluorine, an unsaturated polyester, a polyolefin, and a wax. In the release sheets 12a and 12b, it is preferable that one of the release sheets is a heavy release type release sheet having a large peeling force, and the other release sheet is a light release type release sheet having a small peeling force.

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

3. Manufacture of adhesive sheets

As an example, a method of manufacturing the adhesive sheet 1 using the adhesive composition P will be described.

As an example of the production of the adhesive sheet 1, the coating liquid of the adhesive composition P is applied and heat-treated on the peeling surface of one of the release sheets 12a (or 12b), and the adhesive composition P is thermally bridged. After the coating layer is formed, the peeling surface of the other release sheet 12b (or 12a) is polymerized on the coating layer. When the period of ripening is required, by retaining the ripening period; in the case where the ripening period is not required At this time, the coating layer directly becomes the adhesive layer 11. Thereby, the above-mentioned adhesive sheet 1 is obtained.

As another example of the production of the adhesive sheet 1, the coating liquid of the adhesive composition P is applied and heat-treated on the peeling surface of the one release sheet 12a, and the adhesive composition P is thermally bridged to form a coating layer. A release sheet 12a to which the coating layer adhered was obtained. In addition, the coating liquid of the adhesive composition P is applied and heat-treated on the peeling surface of the other release sheet 12b, and the adhesive composition P is thermally bridged to form a coating layer, thereby obtaining peeling of the coating layer. Sheet 12b. Thereafter, the release sheet 12a to which the coating layer is adhered is bonded to the release sheet 12b to which the coating layer is attached, and the coating layers on both sides are brought into contact with each other. When the ripening period is required, the ripening period is retained; when the ripening period is not required, the laminated coating layer directly becomes the adhesive layer 11. Thereby, the above-mentioned adhesive sheet 1 is obtained.

As a method of applying the coating liquid of the above-mentioned adhesive composition P, for example, a bar coating method, a knife coating method, a roll coating method, a plate coating method, a die coating method, a gravure coating method, or the like can be used. The conditions for heat-treating the applied adhesive composition P are as described above.

In the above-mentioned adhesive sheet 1, since the adhesive layer 11 before the active energy ray irradiation is excellent in the unevenness of the adhesion, even when the adherend has irregularities, it is difficult to form a gap between the unevenness and the adhesive layer 11. Or bubbles may occur, and the adhesive layer 11 may fill the unevenness. Further, the adhesive layer 11 is cured by irradiation with an active energy ray, and the durability is excellent. In particular, the adhesive layer 11 obtained by thermally bridging the adhesive composition P is excellent in moisture heat whitening resistance after irradiation with an active energy ray.

The adhesive layer 11 of the adhesive sheet 1 of the present embodiment is as follows Preferably, it is used to bond two sheets of hard plates to each other.

[layered body]

As shown in Fig. 2, the laminated body 2 according to the present embodiment includes a first hard plate 21 and a second hard plate 22. And an adhesive layer 11 which is located between them and which bonds the 1st hard board 21 and the 2nd hard board 22 mutually. Further, in the laminated body 2 of the present embodiment, the first hard plate 21 has irregularities on the surface on the side of the adhesive layer 11, and specifically has irregularities due to the printed layer 3.

The first hard plate 21 and the second hard plate 22 are not particularly limited as long as the adhesive layer 11 can be bonded. Further, the first hard plate 21 and the second hard plate 22 may be the same material or different materials.

Examples of the first hard plate 21 and the second hard plate 22 include, for example, a glass plate, a plastic plate, a metal plate, a semiconductor plate, and the like, and a laminated body such as a display module or a solar cell module. Hard products, etc.

The glass plate is not particularly limited, and examples thereof include chemically tempered glass, flawless glass, quartz glass, soda lime glass, barium glass, aluminosilicate glass, lead glass, borosilicate glass, and bismuth. Boron silicate glass and the like. The thickness of the glass plate is not particularly limited, but is usually 0.1 mm to 5 mm, preferably 0.2 mm to 2 mm.

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

In addition, one or both sides of the glass plate and the plastic plate can form various functional layers (transparent conductive film, metal layer, cerium oxide layer, hard coating) The layer, the anti-glare layer, and the like may be laminated with optical members.

Examples of the optical member include a polarizing plate (polarizing film), a polarizer, a retardation film (retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast film, a liquid crystal polymer film, a diffusion film, and a hard coating. Layer film, semi-transmissive reflective film, and the like.

Further, examples of the display module include a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroplating luminescent (organic EL) module, and electronic paper. Further, in these display modules, a glass plate, a plastic plate (film), an optical member, or the like is usually laminated. For example, the LCD module has a laminate of polarizing plates that form one side surface of the LCD module.

In the laminated body 2 of the present embodiment, at least one of the first hard plate 21 and the second hard plate 22 preferably includes a polarizing plate. In addition, the second hard plate 22 in the laminated body 2 of the present embodiment is preferably a display module or a part thereof (for example, an optical member such as a polarizing plate), and the first hard plate 21 is preferably protected by a glass plate or the like. board. In this case, the printed layer 3 is generally formed in a frame shape on the side of the adhesive layer 11 of the first hard board 21.

The material constituting the printed 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 unevenness is preferably 3 μm to 45 μm , particularly preferably 5 μm to 35 μm , further preferably 7 μm to 25 μm , and particularly preferably 7 μm ~ 15 μ m.

Further, the thickness (height of the unevenness) of the printed layer 3 is preferably from 3% to 30%, particularly preferably from 3.2% to 20%, and more preferably from 3.5% to 15%, of the thickness of the adhesive layer 11. Thereby, the adhesive layer 11 can surely follow the unevenness of the printed layer 3, and floating, bubbles, and the like do not occur near the unevenness.

The adhesive layer 11 of the laminated body 2 of the present embodiment is an adhesive layer composed of the active energy ray-curable adhesive, and it is preferable that the adhesive layer 11 of the adhesive sheet 1 is irradiated. The active energy line is cured. Here, the active energy ray means that the electromagnetic wave or the charged particle beam has an energy quantum, and specific examples thereof include ultraviolet rays and electron beams. Ultraviolet rays which are easy to handle are also particularly preferable among the active energy rays.

The irradiation of ultraviolet rays can be carried out by a high pressure mercury lamp, a Fusion H lamp, a xenon lamp or the like, and the irradiation amount of the ultraviolet rays is preferably about 50 mW/cm ² to 1000 mW/cm ² . Further, the light amount is preferably ^{50mJ / cm 2 ~ 10000mJ / cm} 2, particularly preferably ^{80mJ / cm 2 ~ 5000mJ / cm} 2, more preferably ^{200mJ / cm 2 ~ 2000mJ / cm} 2. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 KRaD to 1000 KRaD.

When the active energy ray is irradiated to the adhesive layer 11 obtained by thermally bridging the adhesive composition P, the active energy ray-curable component (B) is polymerized and cured. The cured adhesive layer 11 is excellent in durability by irradiation with an active energy ray, and is also excellent in moist heat whitening resistance.

As an example, the laminated body 2 is produced by first peeling off one of the release sheets 12a (or 12b) of the adhesive sheet 1, and exposing the adhesive layer 11 and the first hard board 21 (or the second hard type) in which the adhesive sheet 1 is exposed. Plate 22) is fitted. Next, the other release sheet 12b (or 12a) is peeled off from the adhesive layer 11 of the adhesive sheet 1, and the adhesive layer 11 and the second hard board 22 exposed by the adhesive sheet 1 (or the first hard material) Plate 21) is fitted.

When the adhesive layer 11 and the first hard plate 21 are bonded in the above-described steps, the adhesive layer 11 is excellent in unevenness, and the gap between the unevenness of the printed layer 3 and the adhesive layer 11 is hard to occur. The adhesive layer 11 can fill the unevenness.

Then, the adhesive layer 11 is irradiated with an active energy ray from either of the first hard plate 21 or the second hard plate 22 to cure the adhesive layer 11. At this time, the hard plate irradiated on the side of the active energy ray needs to have active energy ray permeability.

In the laminated body 2, the adhesive layer 11 before the irradiation of the active energy ray is excellent in the unevenness of the adhesion, and it is difficult to generate voids or bubbles between the unevenness of the printed layer 3 and the adhesive layer 11. Further, the adhesive layer 11 which is cured by the irradiation of the active energy ray can maintain the unevenness tracking even when subjected to high-temperature and high-humidity conditions (for example, at 85 ° C and 85% RH for 240 hours). It is excellent in durability by preventing air bubbles from occurring in the vicinity of the unevenness. In addition, the adhesive layer 11 obtained by thermally bridging the adhesive composition P is cured by irradiation with an active energy ray, and it is possible to suppress whitening at the time of returning to normal temperature after performing high-temperature and high-humidity conditions, and it is excellent in moisture-heat-whitening resistance.

The excellent moist heat whitening resistance of the adhesive layer 11 which is cured by irradiation of the active energy ray can be evaluated as follows. For example, the both surfaces of the adhesive layer 11 are sandwiched between two sheets of non-twisted glass having a thickness of 1.1 mm, and the illuminating energy and the amount of active energy of the light are irradiated on at least one side of the untwisted glass to obtain a laminated body. The laminate was stored under the conditions of 85 ° C and 85% RH (humid heat conditions) for 240 hours, and then taken out at 23 ° C and 50% RH under normal temperature and normal humidity. At this time, it was confirmed that the degree of whitening of the above-mentioned adhesive layer 11 was small.

The degree of whitening described above can be quantitatively evaluated by the haze value. Specifically, the value (%) of the haze value (%) before the moist heat condition can be subtracted from the haze value (%) (the value measured based on JIS K7136:2000, the same applies hereinafter) from the above-mentioned laminated body. The subsequent haze value is increased) and evaluated. The haze value after the moist heat condition is increased, preferably less than 5.0 points, and particularly preferably less than 1.0 point. Further, in the above evaluation, it is preferable to use a haze value of almost 0% as the above-mentioned flawless glass. . Moreover, the haze value of the adhesive layer after the above-mentioned moist heat condition is preferably 1.0% or less, particularly preferably 0.9% or less, and further preferably 0.8% or less.

In addition, the total light transmittance (value measured based on JIS K7361-1:1997) of the above-mentioned adhesive layer 11 is preferably 80% or more, particularly preferably 90% or more, and further preferably 99% or more. When the total light transmittance is 80% or more, the transparency is high, and it is suitable for optical use. Such a total light transmittance is easily achieved by using an epoxy-based bridging agent which is difficult to yellow the adhesive layer 11 as a bridging agent (C). Further, the total light transmittance of the adhesive layer 11 hardly changes before and after the irradiation of the active energy ray.

The embodiments described above are described in order to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each of the elements disclosed in the above embodiments includes all design changes and equivalents belonging to the technical scope of the present invention.

For example, either one of the release sheets 12a and 12b of the adhesive sheet 1 can be omitted. Further, the first hard plate 21 may have irregularities other than the printed layer 3 or may have no irregularities. Further, not only the first hard plate 21 but also the side of the adhesive layer 11 of the second hard plate 22 may have irregularities.

[Examples]

The present invention will be specifically described by the following examples, but the scope of the present invention is not limited by the examples and the like.

[Example 1]

1. Modulation of (meth) acrylate copolymer

90 parts by mass of propylene acrylate and propylene were charged into a reaction vessel including a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube. 10 parts by mass of the acid, 200 parts by mass of ethyl acetate, and 0.18 parts by mass of 2,2'-azobisisobutyronitrile were used to replace the air in the reaction vessel with nitrogen. The reaction solution was heated to 60 ° C while stirring in a nitrogen atmosphere, and the reaction was allowed to proceed for 16 hours, and then cooled to room temperature. Here, the molecular weight of a part of the obtained solution was measured by the method described later, and it was confirmed that the (meth)acrylate copolymer (A) having a weight average molecular weight of 400,000 was formed.

2. Modulation of adhesive composition

100 parts by mass of the (meth) acrylate copolymer (A) obtained in the above step (1) (solid content conversion value; the same applies hereinafter); as the active energy ray-curable component (B), polyethylene glycol Diacrylate (trade name "NK ester A-400", manufactured by Shin-Nakamura Chemical Co., Ltd., solid content concentration: 100% by mass) 5 parts by mass; as epoxy type bridging agent (C), 1,3-double (N) , N-diglycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD-C", solid content concentration: 100% by mass), 0.06 parts by mass; as a decane coupling agent, 3- 0.2 parts by mass of glycidoxytrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403"); as a photopolymerization start to dilute the solid content concentration to 50% by mass in methyl ethyl ketone To the agent (D), 0.25 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Corporation, trade name "IRGACURE 184") was mixed, sufficiently stirred, and diluted with methyl ethyl ketone to obtain a solid concentration. It is a coating solution of 39% by mass of the adhesive composition.

Here, the matching of the adhesive composition is shown in Table 1. The details of the abbreviations and the like described in Table 1 are as follows.

[(Meth)acrylate copolymer]

BA: n-butyl acrylate

AA: Acrylic

[Bridge agent]

Epoxy: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD-C")

Isocyanate: Trimethylolpropane modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "CORONATEL")

3. Manufacture of adhesive sheets

The coating solution of the obtained adhesive composition was subjected to a peeling-off peeling sheet which was subjected to a release treatment on one surface of a polyethylene terephthalate film with an anthrone-based release agent (Lindeaceae) The peeling-treated surface of the company's product name "SP-PET752150" was applied by a knife coater to a thickness of 100 μm after drying, and then a coating layer formed by heat treatment at 100 ° C for 4 minutes. Similarly, the coating solution of the same adhesive composition was peeled off on one side of a polyethylene terephthalate film by an oxime-based release agent (Lindeke). The peeling-treated surface of the product type "SP-PET382120" was coated with a knife coater to have a thickness of 100 μm after drying, and then a coating layer formed by heat treatment at 100 ° C for 4 minutes.

Then, the heavy-peelable release sheet to which the coating layer obtained as described above and the light release-type release sheet to which the coating layer obtained is adhered are bonded, and the coating layers on both sides are brought into contact with each other, and are aged at 23 ° C and 50% RH. For 7 days, an adhesive sheet formed of a structure of a heavy release type release sheet/adhesive layer (thickness: 200 μm )/light release type release sheet was produced. In addition, the thickness of the adhesive layer is a value measured based on JIS K7130 using a static pressure thickness gauge (product "PG-02" manufactured by Teclock Co., Ltd.).

[Examples 2 to 8, Comparative Examples 1 to 3]

The ratio of each monomer constituting the (meth) acrylate copolymer (A), the weight average molecular weight of the (meth) acrylate copolymer (A), the type of the active energy ray-curable component (B), and the like The amount, the type of bridging agent (C), the amount of collocation, the amount of photopolymerization initiator (D), the amount of decane coupling agent, and the thickness of the adhesive layer are changed as shown in Table 1, and Example 1 was operated in the same manner to produce a bonding sheet. Further, in Example 2, in the heavy release type release sheet to which the coating layer adhered and the light release type release sheet to which the coating layer adhered, the thickness of each coating layer was 75 μm , and the thickness of the adhesive layer was 150 μm. Make adhesive sheets. Further, in Example 7, as the active energy ray-curable component (B), ε-caprolactone-modified tris(2-propenyloxyethyl) isocyanate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK" In the case of the active energy ray-curable component (B), pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK" was used as the active energy ray-curable component (B). Ester A-TMM-3L", triester: 55 mass%, solid content concentration: 100% by mass).

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: manufactured by Tosoh, HLC-8020

‧GPC column (the following sequence is passed): Tosoh company

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

‧ Determination of solvent: tetrahydrofuran

‧Measurement temperature: 40 ° C

[Test Example 1] (Measurement of press-in stress)

In the adhesive sheet obtained in the example or the comparative example, the light release type release sheet and the heavy release type release sheet were peeled off, and the thickness of the adhesive layer was 600 μm, and a plurality of layers were laminated. The layered body of the obtained adhesive layer was cut in a longitudinal direction of 50 mm × a lateral direction of 50 mm, and this was used as a sample (sample before ultraviolet irradiation).

On the other hand, a tantalum wafer of 5 mm in length × 5 mm in width × 600 μm in thickness obtained by cutting from a tantalum wafer was prepared. The tantalum wafer was placed in the almost central portion of the surface of the sample at a temperature of 23 ° C and a relative humidity of 50% RH, and a universal tensile compression tester (manufactured by Instron Co., Ltd., trade name "Instron 5581") was used. The tantalum wafer was pressed to a depth of 500 μm at a speed of 6 mm/min. with respect to the above sample, and was stopped in this state, and the indentation stress (N) after 10 seconds of press-fitting was measured.

In addition, the same sample as described above was irradiated with ultraviolet rays under the following conditions by using an ultraviolet irradiation device (trade name "EYEGRANDAGEECS-401GX type" manufactured by Eyegraphics Co., Ltd.), and the adhesive layer was cured to obtain a sample after ultraviolet irradiation. The sample after the obtained ultraviolet ray irradiation was subjected to the same operation as the sample before the ultraviolet ray irradiation, and the press-in stress (N) was measured.

[UV irradiation conditions]

‧Light source: high pressure mercury lamp

‧Light quantity: 1000mJ/cm ²

‧ Illuminance: 200mW/cm ²

In the above measurement results, the ratio of the indentation stress after the ultraviolet irradiation to the indentation stress before the ultraviolet irradiation (the indentation stress after the ultraviolet irradiation/the indentation stress before the ultraviolet irradiation) was calculated. These measurement results and calculation results are shown in Table 2.

[Test Example 2] (Measurement of storage modulus)

The light release type release sheet and the heavy release type release sheet were peeled off from the adhesive sheet obtained in the examples or the comparative examples, and the thickness of the adhesive layer was 0.6 mm, and a plurality of layers were laminated. A cylindrical body (having a height of 0.6 mm) having a diameter of 8 mm was punched out from the laminated body of the obtained adhesive layer, and this was used as a sample (a sample before ultraviolet irradiation).

For the above sample, a storage elastic modulus (MPa) was measured under the following conditions by a torsion shear method using a viscoelasticity measuring device (manufactured by Physica Co., Ltd., trade name "MCR300") based on JIS K7244-6.

Measurement frequency: 1 Hz

Measurement temperature: 23 ° C, 85 ° C

In addition, the same sample as described above was irradiated with ultraviolet rays under the following conditions using an ultraviolet irradiation device (manufactured by Eyegraphics Co., Ltd., trade name "EYEGRANDAGEECS-401GX"), and the adhesive layer was cured to obtain a sample after ultraviolet irradiation. The obtained sample after ultraviolet irradiation was subjected to the same operation as the sample before ultraviolet irradiation, and the storage modulus (MPa) was measured.

[UV irradiation conditions]

‧Light source: high pressure mercury lamp

‧Light quantity: 1000mJ/cm ²

‧ Illuminance: 200mW/cm ²

In the above measurement results, the storage modulus after ultraviolet irradiation was calculated, and the ratio of the storage modulus before ultraviolet irradiation at 23 ° C and 85 ° C (storage modulus after ultraviolet irradiation / ultraviolet irradiation) Pre-storage modulus) These measurement results and calculation results are shown in Table 2.

[Test Example 3] (Evaluation of moisture and heat resistance)

The adhesive layer of the adhesive sheet obtained in the examples or the comparative examples was sandwiched between two sheets of non-twisted glass having a thickness of 1.1 mm, and irradiated with ultraviolet rays under the ultraviolet irradiation conditions of Test Example 1 through the glass on one side. , get a layered body. The haze value (%) was measured based on JIS K7136:2000 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., trade name "NDH2000").

Then, the laminate was stored under humid heat conditions of 85 ° C and 85% RH for 240 hours. Then, the temperature was normalized to normal temperature and humidity of 23 ° C and 50% RH, and the haze value was measured based on JIS K7136:2000 using a haze meter (product name "NDH2000" manufactured by Nippon Denshoku Industries Co., Ltd.). %). In addition, the haze value was measured within 30 minutes after returning the laminated body to normal temperature and normal humidity.

According to the above results, the haze value (%) before the moist heat condition was subtracted from the haze value (%) after the moist heat condition, and the haze value after the moist heat condition was calculated to rise. When the haze value after the wet heat condition is increased by less than 1.0 point, the wet heat resistance is good (○), and the haze value after the wet heat condition is increased by more than 1.0 point and less than 5.0 points, the wet heat whitening property is within an appropriate value (Δ), and the damp heat condition The post-haze value was increased by more than 5.0 points and evaluated by poor wet heat whitening (x). The results are shown in Table 2.

[Test Example 4] (concavity and follow-up, durability test)

(a) Production of samples for evaluation

UV-curable ink (manufactured by Imperial Ink Co., Ltd., trade name "POS-911 ink" on the surface of a glass plate (manufactured by NSG PRECISION Co., Ltd., trade name "Corning Glass, Eagle XG", vertical 90 mm × lateral 50 mm × thickness 0.5 mm) ” Screen printing was performed on a frame shape (shape: longitudinal 90 mm × lateral 50 mm, thickness 5 mm) so that the coating thickness was 8 μm and 15 μm . Next, ultraviolet rays (80 W/cm ² , metal halide lamp 2 盏, lamp height 15 cm, belt speed 10 m/min to 15 m/min) were irradiated, and the printed ultraviolet curable ink was cured to have printed unevenness (height of unevenness). : 8 μm and 15 μm ) bump-attached glass sheets.

The adhesive sheet obtained in the examples or the comparative examples was cut into a shape of 90 mm in the longitudinal direction and 50 mm in the transverse direction, and the light release type release sheet was removed to expose the adhesive layer. Then, using a laminator (manufactured by Fuji Co., Ltd., trade name "LPD3214"), the adhesive layer was completely covered by the frame-like printing, and the adhesive sheet was molded on the uneven-attached glass plate.

Thereafter, the following samples for evaluation (1) and (2) were prepared.

(1) After the above-mentioned plastic sealing, the heavy release type release sheet was peeled off, and a glass plate (manufactured by NSG PRECISION Co., Ltd., trade name "Corning Glass, Eagle XG", longitudinal direction 90 mm × lateral direction 50 mm × was peeled off on the exposed adhesive layer. The thickness of 0.5 mm) was molded by the above-mentioned laminator to prepare a sample for evaluation.

(2) A glass plate (manufactured by NSG PRECISION Co., Ltd., trade name "Corning Glass, Eagle XG", longitudinal direction 90 mm × lateral direction 50 mm × thickness 0.5 mm) was inserted into the adhesive, and a hard plate in which polarizing plates were laminated was prepared. Thereafter, in the uneven adhesion glass plate obtained in the above step, the heavy release type release sheet of the molded adhesive sheet is peeled off, and the exposed adhesive layer layer and the polarizing plate surface of the hard plate are joined. On the other hand, the both sides were plastically sealed by the above-mentioned laminator to prepare a sample for evaluation.

(b) Evaluation of bump followability (initial)

The obtained evaluation samples (1) and (2) were pressurized at 0.5 MPa and 50 ° C for 30 minutes in a pressure cooker manufactured by Kurihara Seisakusho Co., Ltd. Then, it was visually confirmed whether or not there was a bubble on the adhesive layer (especially due to the unevenness of the printed layer). The initial irregularities following the absence of air bubbles were good (○), and the initial irregularities following the bubbles (×) were evaluated. The results are shown in Table 2.

(c) Evaluation of durability (concave tracking after durability)

Next, the samples (1) and (2) for evaluation described above were stored under humid heat conditions of 85 ° C and 85% RH for 240 hours. Thereafter, it was confirmed with the naked eye whether or not there was a bubble on the adhesive layer (especially due to the unevenness of the printed layer). The durability (the obscuration-resistance after durability) of the air bubbles was not good (○), and the durability (the unevenness after the endurance) of the air bubbles was evaluated (×). The results are shown in Table 2.

[Test Example 5] (total light transmittance measurement)

The adhesive layer of the adhesive sheet obtained in the example or the comparative example was bonded to the glass, and this was used as a sample for measurement. After the background measurement was performed on the glass, the total light transmittance (%) was measured for the sample for measurement based on JIS K7361-1:1997 using a haze meter (NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.). . The results are shown in Table 2.

【Table 1】

【Table 2】

As can be seen from Table 2, the adhesive layer obtained in the examples, purple It is excellent in the unevenness after the external line irradiation, and is excellent in durability and wet heat whitening resistance after ultraviolet irradiation.

[Industrial Availability]

The adhesive sheet of the present invention is suitably used, for example, for bonding to a display module or a protective sheet having irregularities.

1‧‧‧bonding piece

11‧‧‧Adhesive layer

12a, 12b‧‧‧ peeling film

Claims (12)

An active energy ray-curable adhesive which is an active energy ray-curable adhesive which is cured by irradiation with an active energy ray, and is characterized in that the active energy ray-curable adhesive is made to have a thickness of 600 μm. In the case of the adhesive layer, the surface of the above-mentioned adhesive layer is pressed at a speed of 6 mm/min to a depth of 500 μm for 10 seconds on the surface of 5 mm × 5 mm, and the pressure is applied to the above adhesive. The layer is 4.0N~7.0N before the active energy ray, and 7.0N~15.0N after the active energy ray is applied to the adhesive layer, and the above-mentioned indentation stress after irradiating the adhesive layer with the active energy ray is relative to The ratio of the indentation stress before the active energy ray is applied to the adhesive layer is 1.30 to 2.50. The active energy ray-curable adhesive according to claim 1, wherein the active energy ray-curable adhesive has a storage modulus at 23 ° C, and is curable adhesively bonded to the active energy ray. The agent is 0.01 MPa to 0.2 MPa before the irradiation of the active energy ray, and is 0.02 MPa to 0.5 MPa after the active energy ray-curable adhesive is irradiated with the active energy ray. The active energy ray-curable adhesive according to claim 2, wherein a storage modulus at 23 ° C after the active energy ray is applied to the adhesive layer is irradiated to the adhesive layer The ratio of storage modulus at 23 ° C before the active energy ray is 1.1 to 2.5. The active energy ray-curable adhesive according to claim 1, wherein the active energy ray-curable adhesive has a storage modulus at 85 ° C, and is curable adhesively bonded to the active energy ray. Before the agent illuminates the active energy line It is 0.01 MPa to 0.1 MPa, and is 0.02 MPa to 0.2 MPa after the active energy ray-curable adhesive is irradiated with the active energy ray. The active energy ray-curable adhesive according to claim 4, wherein a storage modulus at 85 ° C after the active energy ray is applied to the adhesive layer is irradiated to the adhesive layer The ratio of storage modulus at 85 ° C before the active energy ray is 1.1 to 3.5. An adhesive sheet comprising two release sheets and an adhesive layer sandwiched by the release sheets in contact with the release faces of the two release sheets, wherein the adhesive layer is patented The active energy ray-curable adhesive according to any one of the items 1 to 5 above. A laminated body comprising two rigid plates and an adhesive layer for bonding the two rigid plates to each other, wherein the adhesive layer is provided by any one of claims 1 to 5 The active energy ray-curable adhesive is cured by irradiation with an active energy ray. The laminated body according to claim 7, wherein at least one of the hard plates has irregularities on a surface on the side of the adhesive layer. The laminated body according to claim 8, wherein the unevenness is due to irregularities of the printed layer. The laminated body according to claim 7, wherein at least one of the hard plates comprises a polarizing plate. The laminated body according to claim 7, wherein one of the two rigid plates is a display module or a part thereof, and the two hard plates are further One piece is a protective plate having frame-like irregularities on the surface on the side of the above-mentioned adhesive layer. The laminated body according to claim 7, wherein the adhesive layer has a total light transmittance of 80% or more.