JP2014125524A - Pressure-sensitive adhesive sheet for image display device, method for producing image display device, and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive sheet for an image display device, which is excellent in refilling a level difference formed by a decorative part or the like and also excellent in air bubble resistance between a touch panel, a method for producing the image display device using the pressure-sensitive adhesive sheet for the image display device, and the image display device.SOLUTION: A pressure-sensitive adhesive sheet 1 for an image display device comprises: a film-shaped pressure-sensitive adhesive layer 2; and a pair of substrate layers 3, 4 laminated such that the pressure-sensitive adhesive layer 2 is sandwiched in between. The pressure-sensitive adhesive layer 2 is formed by a pressure-sensitive resin composition including a structural unit derived from a 4-18C alkyl (meth)acrylate and a structural unit derived from N-(meth)acryloyloxyethyl hexahydrophthalic imide, and has a shearing storage elastic modulus at a temperature of 25°C of 30-150 kPa.

Description

  The present invention relates to an adhesive sheet for an image display device, a method for manufacturing the image display device, and an image display device.

  In recent years, a gap between a transparent protective plate or an information input device (such as a touch panel) in an image display device and a display surface of an image display unit or a gap between a transparent protective plate and an information input device is compared with air. A method has been proposed in which the refractive index is replaced with a transparent material close to the display surface of the transparent protective plate, the information input device, and the image display unit, thereby improving the transparency and suppressing the decrease in luminance and contrast of the image display device. (For example, Patent Document 1). A schematic example of a liquid crystal display device is shown in FIG. 1 as an example of an image display device. The liquid crystal display device with a built-in touch panel is composed of a transparent protective plate (glass or plastic substrate) D1, a touch panel D2, a polarizing plate D3, and a liquid crystal display cell D4. In addition, in order to improve visibility, an adhesive layer D5 may be provided between the transparent protective plate D1 and the touch panel D2, and an adhesive layer D6 may be further provided between the touch panel D2 and the polarizing plate D3.

  By the way, in the information input device and the image display unit, it is necessary to provide input / output wiring at the peripheral portion thereof, and in general, at the peripheral portion of the transparent protective plate so that these wirings cannot be seen from the transparent protective plate surface side. A frame-shaped decorative portion is provided by printing or the like (19 (frame pattern) in FIG. 1 of Patent Document 1). On the other hand, as the adhesive layer D5 or the adhesive layer D6, a film-like adhesive is known (for example, Patent Document 2).

JP 2008-83491 A International Publication No. 2008/053931 Pamphlet

  Since the frame-shaped decorative part has a step of several tens of μm, the film-like pressure-sensitive adhesive is required to have “step-embedding property” that can be embedded without gaps in the vicinity of the step. The adhesive layer is also required to have “bubble resistance” in which bubbles do not occur between the touch panel using the cycloolefin resin at high temperatures (85 ° C.). However, as a result of intensive studies by the present inventors, it has been clarified that the film-like pressure-sensitive adhesive described in Patent Document 2 is inferior in “step embedding property” and “bubble resistance”.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an adhesive sheet for an image display device that is excellent in embedding of a step formed on an adherend and excellent in resistance to bubbles between the touch panel. And Moreover, an object of this invention is to provide the manufacturing method of an image display apparatus using the adhesive sheet for image display apparatuses, and an image display apparatus.

  As a result of intensive studies to solve the above problems, the present inventors have found that a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 4 to 18 carbon atoms and N- (meth) acryloyloxyethylhexahydro It has been found that the above-mentioned problems can be solved if the pressure-sensitive adhesive sheet is formed from a pressure-sensitive adhesive resin composition containing phthalimide and has a pressure-sensitive adhesive layer having specific physical properties. The present invention has been completed based on such findings.

  That is, this invention is equipped with the adhesion layer and a pair of base material layer laminated | stacked so that the adhesion layer may be pinched | interposed, and an adhesion layer is C1-C18 alkyl (meta) whose carbon number is an alkyl group. An image display formed from an adhesive resin composition comprising a structural unit derived from acrylate and a structural unit derived from N- (meth) acryloyloxyethylhexahydrophthalimide, and having a shear storage modulus at 25 ° C. of 30 kPa to 150 kPa An adhesive sheet for an apparatus is provided.

  The present invention also comprises an adhesive layer, first and second base material layers laminated so as to sandwich the adhesive layer, and a carrier layer further laminated on the second base material layer, The pressure-sensitive adhesive layer comprises a pressure-sensitive resin composition containing a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 4 to 18 carbon atoms and a structural unit derived from N- (meth) acryloyloxyethyl hexahydrophthalimide. Provided is an adhesive sheet for an image display device which is formed and has a shear storage elastic modulus at 25 ° C. of 30 kPa to 150 kPa.

  In the present invention, the pressure-sensitive adhesive layer is formed from a pressure-sensitive resin composition containing a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 4 to 18 carbon atoms, and is further subjected to shear storage of the pressure-sensitive adhesive layer at 25 ° C. By adjusting the elastic modulus to be in the range of 30 kPa to 150 kPa, suitable step embedding property and cutting property of the adhesive layer are achieved. For this reason, it becomes possible to embed the level | step difference of a to-be-adhered body, and it becomes possible to cut | disconnect an adhesive layer suitably to a predetermined size at the time of preparation of an adhesive sheet.

  The present invention further includes a step of bonding the adherends to each other via an adhesive layer provided in the adhesive sheet to obtain a laminate, and the laminate is subjected to conditions of 40 ° C to 80 ° C and 0.3 to 0.8 MPa. There is provided a method for manufacturing an image display device, comprising: a step of performing heat and pressure treatment at a step; and a step of irradiating a laminate with ultraviolet rays from any one side of an adherend.

  By using the pressure-sensitive adhesive sheet of the present invention, for example, an image display unit such as a liquid crystal display unit and a touch panel, the image display unit and a transparent protective plate, an image display unit and other image display devices such as a touch panel and a transparent protective plate are used. It is possible to bond together the members (adhesives) that are considered necessary. The present invention can be particularly preferably used when the adherend is a transparent protective plate and a touch panel. Similarly, by using the pressure-sensitive adhesive sheet of the present invention, it is possible to bond members on the viewing side from the image display unit of the image display device. In this case, for example, even if the viewing-side transparent protective plate has a step along the outer peripheral edge, the adhesive layer reliably embeds the step, so that the visibility is not lowered.

  Moreover, this invention provides the image display apparatus manufactured by the said method. The image display device produced using the pressure-sensitive adhesive sheet of the present invention has excellent impact resistance and visibility.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in the embedding property of the level | step difference formed on a to-be-adhered body, the adhesive sheet for image display apparatuses which is excellent in the bubble tolerance between touch panels can be provided. Moreover, this invention can provide the manufacturing method and image display apparatus of an image display apparatus using such an adhesive sheet.

It is sectional drawing which shows an example of the conventional image display apparatus. It is a perspective view which shows one Embodiment of the adhesive sheet which concerns on this invention. It is sectional drawing which shows one Embodiment of the adhesive sheet which concerns on this invention. It is sectional drawing of a base material film. It is sectional drawing which shows a cutting process. It is sectional drawing which shows a removal process. It is sectional drawing which shows a removal process. It is sectional drawing which shows a sticking process. It is sectional drawing which shows one Embodiment of an image display apparatus. It is sectional drawing which shows one Embodiment of an image display apparatus. It is sectional drawing which shows the peeling process of a light peeling separator. It is sectional drawing which shows the sticking process of the adhesion surface to a to-be-adhered body. It is sectional drawing which shows the peeling process of a heavy peeling separator. It is sectional drawing which shows the sticking process of the adhesion surface to a to-be-adhered body. It is a perspective view which shows one Embodiment of the adhesive sheet which concerns on this invention. It is a side view which shows one Embodiment of the adhesive sheet which concerns on this invention. It is sectional drawing of a base material film. It is sectional drawing which shows a cutting process. It is sectional drawing which shows a removal process. It is sectional drawing which shows a removal process. It is sectional drawing which shows a removal process. It is sectional drawing which shows a sticking process. It is sectional drawing which shows the peeling process of a carrier film. It is a schematic diagram which shows the sample measuring method using a wide area dynamic viscoelasticity measuring apparatus.

  Hereinafter, preferred embodiments (first embodiment and second embodiment) of the present invention will be described, but the present invention is not limited to these embodiments. In addition, the description which overlaps with both embodiment shall be demonstrated only in 1st embodiment, and description is abbreviate | omitted suitably in description of 2nd embodiment. In the present specification, “(meth) acrylate” means “acrylate” and “methacrylate” corresponding thereto. Similarly, “(meth) acryl” means “acryl” and “methacryl” corresponding thereto, and “(meth) acryloyl” means “acryloyl” and corresponding “methacryloyl”.

[First embodiment]
<Adhesive sheet for image display device>
A first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 2 and 3, the pressure-sensitive adhesive sheet 1 for an image display device according to the present embodiment includes a pressure-sensitive adhesive layer 2 and a pair of base material layers (a heavy release separator 3 and a light release layer) laminated so as to sandwich the pressure-sensitive adhesive layer 2. The outer edge 3a, 4a of the base material layer projects outward from the outer edge 2a of the pressure-sensitive adhesive layer 2.

  That is, as shown in FIG. 2 and FIG. 3, the pressure-sensitive adhesive sheet 1 according to this embodiment includes a transparent film-like pressure-sensitive adhesive layer 2, a heavy release separator 3 (one base material) sandwiching the pressure-sensitive adhesive layer 2, and a light And a release separator 4 (the other substrate). The adhesive layer 2 is, for example, a transparent film disposed between the transparent protective plate 40 and the touch panel 30 or between the touch panel 30 and the liquid crystal display unit in an image display device such as a touch panel display for a portable terminal. It is.

The pressure-sensitive adhesive layer 2 is, for example, a pressure-sensitive resin containing an alkyl (meth) acrylate component and an N- (meth) acryloyloxyethylhexahydrophthalimide component having 4 to 18 carbon atoms on the heavy release separator 3. It is formed by coating the composition with an arbitrary thickness, irradiating it with an active energy ray and curing it, and then cutting it into a desired size. As the light source of the active energy ray, a light source having a light emission distribution at a wavelength of 400 nm or less is preferable. Can be used. Although the irradiation energy is not particularly limited, in order to 30kPa~150kPa a shear storage modulus at 25 ° C., is preferably 160~650mJ / cm ^2, more preferably 180~600mJ / cm ^2, More preferably, it is 200-500 mJ / cm < ² >.

  Since the adhesive layer 2 is formed from an adhesive resin composition containing a structural unit derived from an alkyl (meth) acrylate having 4 to 18 carbon atoms in the alkyl group, the adhesive layer 2 has an effect that is superior in adhesive strength.

  In the adhesive layer 2, the structural unit derived from the alkyl (meth) acrylate having 4 to 18 carbon atoms in the alkyl group may be derived from a polymer component constituting the adhesive resin composition, It may originate from the monomer component. That is, the structural unit may be imparted to the adhesive resin composition by including a skeleton derived from an alkyl (meth) acrylate having 4 to 18 carbon atoms in the alkyl group in the polymer component, The structural unit may be imparted by including an alkyl (meth) acrylate having 4 to 18 carbon atoms in the alkyl group in the monomer component. However, it is preferable from the viewpoint of improving the transparency of the pressure-sensitive adhesive layer 2 that the structural unit is derived from both the polymer component and the monomer component.

  The content of the structural unit derived from the alkyl (meth) acrylate having 4 to 18 carbon atoms in the alkyl group is 30 to 90% by mass with respect to the total mass of the adhesive layer 2. From the viewpoint of improving the properties and the handling properties. From the above viewpoint, the content is more preferably 40 to 85% by mass, and further preferably 50 to 80% by mass.

  Moreover, the adhesive resin composition has an effect of improving bubble resistance by further having a structural unit derived from N- (meth) acryloyloxyethyl hexahydrophthalimide. Specifically, N- (meth) acryloyloxyethyl hexahydrophthalimide is a compound represented by the following formula (a). The content of the structural unit derived from N- (meth) acryloyloxyethyl hexahydrophthalimide is 3 to 20% by mass with respect to the total mass of the adhesive layer 2, so that the adhesiveness, transparency and bubble resistance are improved. It is preferable from the point which can improve more. From the above viewpoint, the content is more preferably 5 to 15% by mass, and further preferably 7 to 13% by mass.

式（ａ）中、Ｒは水素原子又はメチル基を示す。

In the formula (a), R represents a hydrogen atom or a methyl group.

  The adhesive layer 2 preferably has a shear storage modulus at 25 ° C. of 30 kPa to 150 kPa.

(Measurement of glass transition temperature, loss modulus and shear storage modulus)
A pressure-sensitive adhesive layer 2 having a thickness of 0.5 mm, a width of 10 mm, and a length of 10 mm was prepared, and the condition “Share Sandwich Mode, Frequency 1” was measured using a wide-range dynamic viscoelasticity measuring apparatus (manufactured by Rheometric Scientific, Solids Analyzer RSA-II). 0.0 Hz, measurement temperature range of -20 to 100 ° C., and rate of temperature increase of 5 ° C./min ”.

  When the adhesive layer 2 has a shear storage modulus at 25 ° C. of less than 30 kPa, the cutting property (punching property) is lowered. On the other hand, when the shear storage elastic modulus at 25 ° C. exceeds 150 kPa, the step embedding property decreases. From the above viewpoint, the shear storage modulus at 25 ° C. is preferably in the range of 35 kPa to 120 kPa, and more preferably in the range of 35 kPa to 110 kPa.

  The glass transition temperature of the pressure-sensitive adhesive layer 2 is preferably in the range of 10 to 50 ° C., more preferably in the range of 15 to 45 ° C., from the viewpoint of maintaining good step embedding and film forming properties. There exists a tendency which can improve adhesiveness and level | step difference embedding property that a glass transition temperature is 50 degrees C or less. Moreover, when the glass transition temperature is 10 ° C. or higher, when the light release separator 4 described later is peeled off, it tends to be favorably peeled off. The glass transition temperature in the present application is a temperature at which tan δ exhibits a peak in the above measurement temperature range. However, when two or more tan δ peaks are observed in this temperature range, the temperature at which the value of tan δ is the largest is taken as the glass transition temperature. Here, tan δ is a value obtained by dividing the loss elastic modulus by the shear storage elastic modulus, and the loss elastic modulus and the shear storage elastic modulus are values measured by a wide area dynamic viscoelasticity measuring apparatus.

  Moreover, the adhesive layer 2 tends to improve the step burying property when the tan δ at 40 to 80 ° C. is 1.2 to 2.

  The thickness of the pressure-sensitive adhesive layer 2 is not particularly limited because it is appropriately adjusted depending on the intended use and method, but is preferably about 0.02 to 3 mm, more preferably 0.1 to 1 mm, and 0.15 mm (150 μm) to 0.00. 5 mm (500 μm) is more preferable. When used in this range, the transparent adhesive sheet 1 for laminating an optical member on the display exhibits a particularly excellent effect.

  The adhesive resin composition comprises (A) (meth) acrylic acid derivative polymer, (B) (meth) acrylic acid derivative monomer having one (meth) acryloyl group in the molecule, (C) bifunctional ( It contains a crosslinking agent having a (meth) acryloyl group and (D) a photopolymerization initiator.

[(A) component: (A) (meth) acrylic acid derivative polymer]
The (A) (meth) acrylic acid derivative polymer is a polymer obtained by polymerizing one type of monomer having one (meth) acryloyl group in the molecule, or by copolymerizing two or more types in combination. In addition, if it is a range which does not impair the effect of this embodiment, (A) component is a compound which has 2 or more of (meth) acryloyl groups in a molecule | numerator, or a polymerizable compound which does not have a (meth) acryloyl group (A compound having one polymerizable unsaturated bond in the molecule such as acrylonitrile, styrene, vinyl acetate, ethylene, propylene, a compound having two or more polymerizable unsaturated bonds in the molecule such as divinylbenzene) ) Copolymerized with an acrylic acid derivative polymer.

  (A) As a monomer which has one (meth) acryloyl group in a molecule | numerator which forms a component, (meth) acrylic acid; (meth) acrylic acid amide; N- (meth) acryloyloxyethyl hexahydrophthalimide ( Compound represented by the above formula (a)); (meth) acryloylmorpholine; methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate , N-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate (N-lauryl (me ) Acrylate), alkyl (meth) acrylates having 1 to 18 carbon atoms of an alkyl group such as stearyl (meth) acrylate; (meth) acrylates having an aromatic ring such as benzyl (meth) acrylate and phenoxyethyl (meth) acrylate; cyclohexyl (Meth) acrylates having alicyclic groups such as (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate; N, N-dimethylaminoethyl (meth) Acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-hydroxyethyl (meth) a (Meth) acrylamide derivatives such as rilamide; (meth) acrylates having isocyanate groups such as 2- (2-methacryloyloxyethyloxy) ethyl isocyanate and 2- (meth) acryloyloxyethyl isocyanate; alkylene glycol chain-containing (meth) acrylates Etc.

Among the above compounds, the component (A) preferably contains an alkyl (meth) acrylate having 4 to 18 carbon atoms in the alkyl group represented by the following formula (b), and has 6 to 12 carbon atoms. (Meth) acrylate having an alkyl group is more preferred. Moreover, it is preferable that the content rate of such (meth) acrylate is 50-90 mass% with respect to the copolymerized polymer total mass, It is more preferable that it is 60-80 mass%, 65- More preferably, it is 75 mass%. When the content ratio of (meth) acrylate represented by the following formula (b) is in such a range, the workability of the formed adhesive layer 2 is improved, and the adhesive layer 2 and the transparent protective plate 40 (glass substrate, Adhesion with a plastic substrate or the like is also improved. In general, a polymer having such a copolymerization ratio can be obtained by blending each monomer in the same ratio as the above-mentioned copolymerization ratio and copolymerizing them. The polymerization rate is more preferably substantially close to 100% by mass.
CH ₂ = CXCOOR (b)
In formula (b), X represents a hydrogen atom or a methyl group, and R represents an alkyl group having 4 to 18 carbon atoms.

  Examples of the alkyl (meth) acrylate having 4 to 18 carbon atoms in the alkyl group include n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, and n-octyl (meth) acrylate. , Isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, etc., among which n-butyl (meth) acrylate, isooctyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate and n-octyl (meth) acrylate are preferable, and 2-ethylhexyl (meth) acrylate is more preferable. Further, alkyl acrylate is more preferable than alkyl methacrylate. These alkyl (meth) acrylates may be used in combination of two or more.

  Among alkyl (meth) acrylates having 4 to 18 carbon atoms in the alkyl group, it is particularly preferable that stearyl (meth) acrylate is included. The content ratio of the stearyl (meth) acrylate is preferably 50 to 98% by mass, more preferably 60 to 95% by mass, and 70 to 90% by mass with respect to the total mass of the copolymerized polymer. More preferably. When the content ratio of stearyl (meth) acrylate is in such a range, the adhesion between the adhesive layer 2 and the transparent protective plate 40 (glass substrate, plastic substrate, etc.) and surface flatness are further improved, and the dielectric constant. Can be further reduced. In general, a polymer having such a copolymerization ratio can be obtained by blending each monomer in the same ratio as the above-mentioned copolymerization ratio and copolymerizing them.

  The stearyl (meth) acrylate is more preferably isostearyl (meth) acrylate.

  Other monomers copolymerized with an alkyl (meth) acrylate having 4 to 18 carbon atoms in the alkyl group are not limited to those described above, but include a hydroxyl group, a morpholino group, an amino group, a carboxyl group, a cyano group, A monomer having a polar group such as a group derived from a carbonyl group, a nitro group or an alkylene glycol is preferred. By the (meth) acrylate having these polar groups, the adhesiveness between the adhesive layer 2 and the transparent protective plate 40 is improved.

In particular, it is preferable to use together an alkyl (meth) acrylate having 4 to 18 carbon atoms in the alkyl group and an alkylene glycol chain-containing (meth) acrylate represented by the following formula (x).
CH ₂ = CXCOO (C _p H _2p O) _q R (x)
In formula (x), X represents a hydrogen atom or a methyl group, R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, p represents an integer of 2 to 4, and q represents an integer of 1 to 10. Show.

  Examples of the alkylene glycol chain-containing (meth) acrylate represented by the formula (x) include 2-hydroxyethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3-hydroxypropyl. (Meth) acrylate, 1-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 1-hydroxybutyl (meth) acrylate, etc. Hydroxyl group-containing (meth) acrylates; diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, hexaethylene glycol mono ( Polyethylene glycol mono (meth) acrylates such as acrylate); Polypropylene glycol mono (meth) acrylates such as dipropylene glycol mono (meth) acrylate, tripropylene glycol mono (meth) acrylate, octapropylene glycol mono (meth) acrylate; Polybutylene glycol mono (meth) acrylates such as butylene glycol mono (meth) acrylate and tributylene glycol mono (meth) acrylate; methoxytriethylene glycol (meth) acrylate, methoxytetraethylene glycol (meth) acrylate, methoxyhexaethylene glycol ( (Meth) acrylate, methoxyoctaethylene glycol (meth) acrylate, methoxynonaethylene glycol (meth) Alkoxypolyalkylene glycols such as acrylate, methoxypolyethylene glycol (meth) acrylate, methoxyheptapropylene glycol (meth) acrylate, ethoxytetraethylene glycol (meth) acrylate, butoxyethylene glycol (meth) acrylate, butoxydiethylene glycol (meth) acrylate ) Acrylate and the like. Among these, 2-hydroxyethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 1-hydroxypropyl (meth) acrylate, 4 -Hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 1-hydroxybutyl (meth) acrylate are preferred, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate is more preferable, and 2-hydroxyethyl (meth) acrylate is more preferable. These alkylene glycol chain-containing (meth) acrylates may be used in combination of two or more.

  The weight average molecular weight of the component (A) is preferably 80,000 to 700,000, as converted by gel permeation chromatography (GPC) using a standard polystyrene calibration curve. When the weight average molecular weight is 80,000 or more, it is possible to obtain the adhesive layer 2 having an adhesive force that does not peel off from the transparent protective plate 40 or the like, and when it is 700,000 or less, the adhesive resin. The viscosity of the composition does not become too high, and the processability when forming the sheet-like adhesive layer 2 is improved. From the above viewpoint, the weight average molecular weight of the component (A) is more preferably 100,000 to 500,000, and more preferably 100,000 to 300,000.

  As the polymerization method for component (A), known polymerization methods such as solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization and the like can be used.

  As the polymerization initiator for polymerizing the component (A), a compound that generates a radical by heat can be used. Specifically, organic peroxides such as benzoyl peroxide and lauroyl peroxide; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), etc. Azo compounds.

  The content of the component (A) is preferably 15 to 80% by mass, more preferably 30 to 70% by mass, and more preferably 35 to 65% by mass with respect to the total mass of the adhesive resin composition. Further preferred. When the content of the component (A) is 10 to 80% by mass, the viscosity of the pressure-sensitive adhesive resin composition falls within an appropriate viscosity range when the pressure-sensitive adhesive layer 2 is produced, and the workability is improved. Further, the obtained adhesive layer 2 has good adhesiveness to the transparent protective plate 40 such as glass or plastic.

[(B) component: (B) (meth) acrylic acid derivative monomer having one (meth) acryloyl group in the molecule]
(B) The (meth) acrylic acid derivative monomer having one (meth) acryloyl group in the molecule is exemplified as a monomer having one (meth) acryloyl group forming the component (A) in the molecule. The thing similar to a compound is mentioned.

  In the present embodiment, from the viewpoint of securing adhesiveness and transparency, the component (B) preferably contains an alkyl (meth) acrylate having an alkyl group with 4 to 18 carbon atoms, It is more preferable to contain an alkyl (meth) acrylate having 6 to 18 carbon atoms, and it is more preferable to contain isostearyl (meth) acrylate. Moreover, it is preferable that (B) component contains N- (meth) acryloyloxyethyl hexahydrophthalimide represented by the said Formula (a) from a viewpoint of adhesiveness, transparency, and handleability.

  (B) As for content of a component, 15-80 mass% is preferable with respect to the total mass of an adhesive resin composition. When the content of the component (B) is in the range of 15 to 80% by mass, the viscosity of the pressure-sensitive adhesive resin composition falls within an appropriate viscosity range for producing the pressure-sensitive adhesive layer 2, and the workability is improved. Moreover, it will be excellent also in the adhesiveness and transparency of the obtained adhesive sheet 1. FIG. And the obtained adhesion layer 2 is excellent also in level | step difference embedding property. From the above viewpoint, the content of the component (B) is more preferably 25 to 65% by mass, and further preferably 30 to 60% by mass.

[Component (C): (C) Crosslinking agent having a bifunctional (meth) acryloyl group]
(C) As a specific example of a component, the compound represented by following formula (c)-(h) is illustrated suitably. However, in formulas (c), (d) and (e), s represents an integer of 1 to 20, and in formulas (f) and (g), m and n each independently represents an integer of 1 to 10. Show.

  Urethane di (meth) acrylate having a urethane bond can also be used as the component (C).

  The urethane di (meth) acrylate having a urethane bond preferably has a polyalkylene glycol chain from the viewpoint of good compatibility with other components. Moreover, it is preferable to have an alicyclic structure from a viewpoint of ensuring transparency. When the compatibility between the component (C), the component (A) and the component (B) is low, the cured product may become cloudy.

  A side chain (meth) acryl-modified (meth) acrylate polymer can also be used as the component (C).

  The side chain (meth) acryl-modified (meth) acrylate polymer may be a (meth) acrylate polymer having a side chain modified with a (meth) acryloyl group. From the viewpoint of step embedding and surface flatness, the following general formula It is preferable to have a structural unit represented by (1) and a structural unit represented by the following general formula (2). From the viewpoint of haze value, step embedding property and surface flatness, R1 is preferably an alkyl group having 9 to 18 carbon atoms. From such a viewpoint, the side chain (meth) acryl-modified (meth) acrylate polymer is more preferably the component (A). The (A) component side chain is (meth) acryl modified to make the (C) component so that the compatibility between the (A) component and the (C) component is better, so the haze value is small and the surface flatness is also improved. A more excellent adhesive film can be obtained.

  As a method of modifying the side chain by (meth) acryl, for example, a structural unit having a hydroxyl group or a structural unit having a carboxyl group represented by the following general formula (3) in the component (A) is incorporated in the main chain of the polymer. There is a method of adding (meth) acrylate having an isocyanate group such as 2-isocyanatoethyl (meth) acrylate represented by the following general formula (4). Further, as another method, for example, there is a method in which a structural unit having a glycidyl group as represented by the following general formula (5) is provided in the main chain of the polymer and (meth) acrylic acid is added thereto. Can be mentioned. Furthermore, although the method of forming a (meth) acryl side chain by graft polymerization is also mentioned, it has isocyanate groups, such as 2-isocyanatoethyl (meth) acrylate, in the hydroxyl group as shown by following General formula (3) ( A method of adding (meth) acrylate or a method of adding (meth) acrylic acid to a glycidyl group as shown by the following general formula (5) is more preferable.

  When a (meth) acrylate having an isocyanate group is added to a hydroxyl group represented by the following general formula (3), the (meth) acrylate having an isocyanate group is added in an amount of 0.01 to 0. It is preferable to add such that the ratio is 9 equivalents. Similarly, when (meth) acrylic acid is added to a glycidyl group as represented by the following general formula (5), a ratio of 0.01 to 0.9 equivalent of (meth) acrylic acid to 1 equivalent of glycidyl group It is preferable to add such that

  According to these methods, a structure in which the side chain (meth) acryloyl group is bonded to the main chain via a urethane bond or an ester bond is obtained. It is preferable to have these structures from the viewpoint of step embedding.

（式中、Ｒは水素あるいはメチル基を表し、Ｒ^１は炭素数４〜１８のアルキル基あるいは脂環式アルキル基を表し、Ｘは、−ＣＨ_２ＣＨ_２−、−（ＣＨ_２ＣＨ_２Ｏ）_ｐＣＨ_２ＣＨ_２−｛ｐは１〜５００までの整数｝、−Ｒ^２−ＯＣＯＮＨ−Ｒ^３−あるいは−Ｒ^４−ＣＨ（ＯＨ）ＣＨ_２−を表し、Ｒ^２、Ｒ^３及びＲ^４はそれぞれ独立に炭素数１〜１０のアルキレン基あるいは脂環式アルキレン基を表す。）

(In the formula, R represents hydrogen or a methyl group, R ¹ represents an alkyl group having 4 to 18 carbon atoms or an alicyclic alkyl group, and X represents —CH ₂ CH ₂ —, — (CH ₂ CH ₂ O). _P CH ₂ CH ₂ — {p is an integer from ^{1 to} 500}, —R ² —OCONH—R ³ — or —R ⁴ —CH (OH) CH ₂ —, R ² , R ³ and R ⁴ Each independently represents an alkylene group having 1 to 10 carbon atoms or an alicyclic alkylene group.)

R ¹ is preferably an alkyl group having 9 to 18 carbon atoms, and more preferably an alkyl group having 12 to 18 carbon atoms, from the viewpoint of further reducing the surface flatness and haze value.

（式中、Ｒは水素あるいはメチル基を表し、Ｒ^２は炭素数１〜１０のアルキレン基あるいは脂環式アルキレン基を表す。）

(In the formula, R represents hydrogen or a methyl group, and R ² represents an alkylene group having 1 to 10 carbon atoms or an alicyclic alkylene group.)

（式中、Ｒは水素あるいはメチル基を表し、Ｒ^３は炭素数１〜１０のアルキレン基あるいは脂環式アルキレン基を表す。）

(In the formula, R represents hydrogen or a methyl group, and R ³ represents an alkylene group having 1 to 10 carbon atoms or an alicyclic alkylene group.)

（式中、Ｒは水素あるいはメチル基を表し、Ｒ^４は炭素数１〜１０のアルキレン基あるいは脂環式アルキレン基を表す。）

(In the formula, R represents hydrogen or a methyl group, and R ⁴ represents an alkylene group having 1 to 10 carbon atoms or an alicyclic alkylene group.)

  Next, the optimal content when using a side chain (meth) acryl-modified (meth) acrylate polymer as the component (C) varies depending on the modification rate of the side chain, but if the content is too large, the adhesive strength decreases. However, problems such as peeling and easy entry of bubbles tend to occur. On the other hand, if the amount is too small, the holding power is lowered and the reliability tends to be lowered.

  The component (C) has a weight average molecular weight of preferably 100,000 or less, more preferably 300 to 100,000, from the viewpoint of further suppressing generation of bubbles and peeling under high temperature or high temperature and high humidity. More preferably, it is 500-80,000.

  It is preferable that content of (C) component is 15 mass% or less with respect to the total mass of an adhesive resin composition. When the content is 15% by mass or less, since the crosslinking density does not become too high, it is possible to obtain the pressure-sensitive adhesive layer 2 having sufficient adhesiveness, high elasticity, and no brittleness. Further, from the viewpoint of further improving the step embedding property, the content of the component (C) is more preferably 10% by mass or less, and further preferably 7% by mass or less.

  Although there is no restriction | limiting in particular about the minimum of content of (C) component, from a viewpoint which makes film-forming property favorable, it is preferable that it is 0.1 mass% or more, and it is more preferable that it is 2 mass% or more, More preferably, it is 3 mass% or more.

[(D) component: (D) photopolymerization initiator]
(D) A component accelerates | stimulates hardening reaction by irradiation of an active energy ray. Here, active energy rays refer to ultraviolet rays, electron beams, α rays, β rays, γ rays and the like.

  The component (D) is not particularly limited, and known materials such as benzophenone, anthraquinone, benzoyl, sulfonium salt, diazonium salt, onium salt and the like can be used.

  Specifically, benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy-4,4 ″- Dimethylaminobenzophenone, α-hydroxyisobutylphenone, 2-ethylanthraquinone, t-butylanthraquinone, 1,4-dimethylanthraquinone, 1-chloroanthraquinone, 2,3-dichloroanthraquinone, 3-chloro-2-methylanthraquinone, 1, 2-benzoanthraquinone, 2-phenylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenyl Ethane Aromatic ketone compounds such as 1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one and 2,2-diethoxyacetophenone; Benzoin compounds such as benzoin, methylbenzoin and ethylbenzoin; Benzoin methyl ether Benzoin ether compounds such as benzoin ethyl ether, benzoin isobutyl ether and benzoin phenyl ether; benzyl compounds such as benzyl and benzyldimethyl ketal; ester compounds such as β- (acridin-9-yl) (meth) acrylic acid; 9-phenyl Acridine compounds such as acridine, 9-pyridylacridine, 1,7-diacridinoheptane; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5- Di (m-metoki Ciphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p- Methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) 5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole Dimer, 2,4,5-triarylimidazole dimer such as 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer; 2-benzyl-2-dimethylamino-1- ( 4-Morpholinophenyl) -1-butanone; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propane; bis (2, , 6-trimethyl benzoyl) - phenyl phosphine oxide; oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone), and the like. These compounds may be used in combination.

  Particularly, as the component (D) that does not color the adhesive resin composition, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- ( Α-hydroxyalkylphenone compounds such as 2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one; bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide Acylphosphine oxide compounds such as bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; Hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propyl Pannon), and the like, is preferable, particularly combinations thereof.

  In order to produce a particularly thick sheet (adhesion layer 2), the component (D) is bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl)- It preferably contains an acyl phosphine oxide compound such as 2,4,4-trimethyl-pentylphosphine oxide or 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

  The content of the component (D) in this embodiment is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass with respect to the total mass of the adhesive resin composition, and 0 More preferably, it is 1 to 0.5% by mass. By setting the content of the component (D) to 5% by mass or less, it is possible to obtain the pressure-sensitive adhesive layer 2 that has high transmittance, does not have a yellowish hue, and is excellent in step embedding property.

[Other additives]
In addition to the components (A), (B), (C), and (D), the adhesive resin composition may contain various additives as necessary. Examples of the various additives that can be contained include, for example, a polymerization inhibitor such as paramethoxyphenol added for the purpose of enhancing the storage stability of the adhesive resin composition, and an adhesive layer 2 obtained by photocuring the adhesive resin composition. Antioxidants such as triphenyl phosphite added for the purpose of increasing the heat resistance of light, and light stabilizers such as HALS (Hindered Amine Light Stabilizer) added for the purpose of increasing the resistance of the adhesive resin composition to light such as ultraviolet rays And a silane coupling agent to be added to increase the adhesion of the adhesive resin composition to glass or the like.

  When obtaining the pressure-sensitive adhesive sheet 1 for an image display device, the pressure-sensitive adhesive layer 2 is sandwiched between a polymer film substrate (heavy release separator 3) such as a polyethylene terephthalate film and a cover film (light release separator 4) made of the same material. It becomes composition. At this time, in order to control the peelability between the pressure-sensitive adhesive layer 2 and the base material such as the polyethylene terephthalate film and the cover film, the pressure-sensitive resin composition includes a surfactant such as polydimethylsiloxane or fluorine. Can be contained.

  These additives may be used alone or in combination with a plurality of additives. The content of these other additives is usually a small amount compared to the total content of the above (A), (B), (C) and (D), and generally the total content of the adhesive resin composition. It is about 0.01-5 mass% with respect to mass.

  As the heavy release separator 3, for example, a polymer film such as polyethylene terephthalate, polypropylene, polyethylene, or polyester is preferable, and among them, a polyethylene terephthalate film (hereinafter sometimes referred to as “PET film”) is more preferable. From the viewpoint of workability, the thickness of the heavy release separator 3 is preferably from 50 μm to 200 μm, more preferably from 60 μm to 150 μm, and even more preferably from 70 μm to 130 μm. The planar shape of the heavy release separator 3 is larger than the planar shape of the pressure-sensitive adhesive layer 2, and the outer edge 3 a of the heavy release separator 3 preferably projects outward from the outer edge 2 a of the pressure-sensitive adhesive layer 2. The amount by which the outer edge 3a of the heavy release separator 3 protrudes from the outer edge 2a of the adhesive layer 2 is preferably 2 mm or more and 20 mm or less from the viewpoint of ease of handling, ease of peeling, and adhesion of dust and the like. More preferably, it is 4 mm or more and 10 mm or less. When the planar shape of the pressure-sensitive adhesive layer 2 and the heavy release separator 3 is a rectangular shape such as a rectangle, the amount of the outer edge 3a of the heavy release separator 3 protruding from the outer edge 2a of the pressure-sensitive adhesive layer 2 is 2 mm at least on one side. It is preferably 20 mm or less, more preferably 4 mm or more and 10 mm or less on at least one side, more preferably 2 mm or more and 20 mm or less on all sides, and 4 mm or more and 10 mm or less on all sides. It is particularly preferred.

  As the light release separator 4, for example, a polymer film such as polyethylene terephthalate, polypropylene, polyethylene, and polyester is preferable, and among them, a polyethylene terephthalate film is more preferable. From the viewpoint of workability, the thickness of the light release separator 4 is preferably 25 μm or more and 150 μm or less, more preferably 30 μm or more and 100 μm or less, and further preferably 40 μm or more and 75 μm or less. The planar shape of the light release separator 4 is larger than the planar shape of the pressure-sensitive adhesive layer 2, and the outer edge 4 a of the light release separator 4 preferably projects outward from the outer edge 2 a of the pressure-sensitive adhesive layer 2. The amount by which the outer edge 4a of the light release separator 4 protrudes from the outer edge 2a of the adhesive layer 2 is preferably 2 mm or more and 20 mm or less from the viewpoint of ease of handling, ease of peeling, and adhesion of dust and the like. More preferably, it is 4 mm or more and 10 mm or less. When the planar shape of the pressure-sensitive adhesive layer 2 and the light release separator 4 is a rectangular shape such as a rectangle, the amount of the outer edge 4a of the light release separator 4 protruding from the outer edge 2a of the pressure-sensitive adhesive layer 2 is 2 mm at least on one side. It is preferably 20 mm or less, more preferably 4 mm or more and 10 mm or less on at least one side, more preferably 2 mm or more and 20 mm or less on all sides, and 4 mm or more and 10 mm or less on all sides. It is particularly preferred.

  The peel strength between the light release separator 4 and the adhesive layer 2 is preferably lower than the peel strength between the heavy release separator 3 and the adhesive layer 2. Thereby, the heavy release separator 3 is less likely to peel from the adhesive layer 2 than the light release separator 4. Further, as will be described later, since the blade B is passed through the adhesive layer 2 toward the heavy release separator 3, the outer edge portion of the adhesive layer 2 is pressed against the heavy release separator 3. Thereby, the heavy release separator 3 becomes more difficult to peel from the adhesive layer 2 than the light release separator 4, and the light release separator 4 can be released before the heavy release separator 3 is peeled off. Therefore, the separators 3 and 4 can be peeled one by one, and the work of peeling the separators 3 and 4 and sticking the adhesive layer 2 to separate adherends can be reliably performed one by one. The peel strength between the heavy release separator 3 and the pressure-sensitive adhesive layer 2 and between the light release separator 4 and the pressure-sensitive adhesive layer 2 can be adjusted, for example, by subjecting the heavy release separator 3 and the light release separator 4 to surface treatment. . Examples of the surface treatment method include a mold release treatment with a silicone compound or a fluorine compound.

<Method for producing pressure-sensitive adhesive sheet for image display device>
The adhesive sheet 1 demonstrated above is manufactured as follows. First, as shown in FIG. 4, a base material film 10 in which the adhesive layer 2 is formed on the heavy release separator 3 and the temporary separator 6 is formed on the adhesive layer 2 is prepared. The temporary separator 6 is, for example, a layer made of the same material as the light release separator 4.

  Subsequently, as shown in FIG. 5, the temporary separator 6 and the adhesive layer 2 are cut into desired shapes by a punching device (not shown) provided with a blade B. The punching device may be a crank punching device, a reciprocating punching device, or a rotary punching device. From the viewpoint of peelability of each substrate, a rotary punching device is preferable. In this step, it is preferable that the blade B is passed through the temporary separator 6 and the adhesive layer 2 at a depth reaching the heavy release separator 3 to cut the temporary separator 6 and the adhesive layer 2. Thereby, the notch part 3c is formed in the heavy peeling separator 3, and peeling of the heavy peeling separator 3 from the adhesion layer 2 becomes easy.

  Subsequently, the outer portions of the temporary separator 6 and the adhesive layer 2 are removed as shown in FIG. 6, the temporary separator 6 is peeled off from the adhesive layer 2 as shown in FIG. 7, and the adhesive as shown in FIG. A light release separator 4 is affixed to layer 2. The adhesive sheet 1 is completed through the above steps.

<Image display device>
Next, an image display device manufactured using the adhesive sheet 1 will be described. The pressure-sensitive adhesive layer 2 included in the pressure-sensitive adhesive sheet 1 can be applied to various image display devices. Examples of the image display device include a plasma display (PDP), a liquid crystal display (LCD), a cathode ray tube (CRT), a field emission display (FED), an organic EL display (OELD), a 3D display, and electronic paper (EP). . The adhesive layer 2 of the present embodiment is used for combining and bonding functional layers having functionality such as an antireflection layer, an antifouling layer, a dye layer, and a hard coat layer of the image display device, and the transparent protective plate 40. You can also.

  The antireflection layer may be a layer having an antireflection property with a visible light reflectance of 5% or less, and is a layer treated by a known antireflection method on a transparent substrate such as a transparent plastic film. Can be used.

  The antifouling layer is for preventing the surface from getting dirty, and a known layer composed of a fluorine-based resin or a silicone-based resin can be used to reduce the surface tension.

  The dye layer is used to increase color purity, and is used to reduce unnecessary light when the color purity of light emitted from the image display unit 7 such as a liquid crystal display unit is low. The pigment | dye which absorbs the light of an unnecessary part can be melt | dissolved in resin, and it can obtain by forming or laminating | stacking on base films, such as a polyethylene film and a polyester film.

  The hard coat layer is used to increase the surface hardness. As a hard-coat layer, what formed or laminated | stacked acrylic resin, such as urethane acrylate and an epoxy acrylate; base films, such as a polyethylene film, can be used, for example. Similarly, in order to increase the surface hardness, it is also possible to use a hard coat layer formed or laminated on a transparent protective plate 40 such as glass, acrylic resin or polycarbonate.

  The adhesive layer 2 can be used by being laminated on the polarizing plates 20 and 22. In this case, it can be laminated on the viewing side of the polarizing plates 20 and 22, or can be laminated on the opposite side.

  When used on the viewing side of the polarizing plates 20 and 22, an antireflection layer, an antifouling layer and a hard coat layer can be laminated on the further viewing side of the adhesive layer 2, and the polarizing plates 20 and 22 and the liquid crystal cell When used in between, a functional layer can be laminated on the viewing side of the polarizing plates 20 and 22.

  When setting it as such a laminated body, the adhesion layer 2 can be laminated | stacked using a roll lamination, a vacuum bonding machine, or a single wafer bonding machine.

  It is preferable that the adhesive layer 2 is disposed between the image display unit 7 of the image display device and the transparent protective plate 40 on the front side of the viewing side and at an appropriate position on the viewing side. Specifically, it is preferably applied between the image display unit 7 and the transparent protective plate 40.

  In the image display device in which the touch panel 30 is combined with the image display unit 7, it is preferable that the touch panel 30 is applied between the touch panel 30 and the image display unit 7 and / or between the touch panel 30 and the transparent protective plate 40. As long as the adhesive layer 2 of the present embodiment is applicable to the configuration of the image display device, the position is not limited to the above-described position.

  Hereinafter, a liquid crystal display device which is one of image display devices will be described in detail with reference to FIGS. 9 and 10 as an example.

  FIG. 9 is a side sectional view schematically showing one embodiment of the liquid crystal display device of the present invention. The liquid crystal display device shown in FIG. 9 includes an image display unit 7 in which a backlight system 50, a polarizing plate 22, a liquid crystal display cell 12, and a polarizing plate 20 are laminated in this order, and a polarizing plate on the viewing side of the liquid crystal display device. The transparent resin layer 32 provided on the upper surface 20 and a transparent protective plate (protective panel) 40 provided on the surface thereof. A step 60 provided on the surface of the transparent protective plate 40 is embedded with a transparent resin layer 32. The transparent resin layer 32 basically corresponds to the adhesive layer 2 of the present embodiment. Although the thickness of the step 60 varies depending on the size of the liquid crystal display device and the like, it is particularly useful to use the adhesive layer 2 of the present embodiment when the thickness is 40 μm to 100 μm.

  FIG. 10 is a side cross-sectional view schematically showing a liquid crystal display device equipped with a touch panel 30, which is an embodiment of the liquid crystal display device of the present invention. 10 includes an image display unit 7 in which a backlight system 50, a polarizing plate 22, a liquid crystal display cell 12, and a polarizing plate 20 are laminated in this order, and a polarizing plate on the viewing side of the liquid crystal display device. 20, a transparent resin layer 32 provided on the top surface, a touch panel 30 provided on the top surface of the transparent resin layer 32, a transparent resin layer 31 provided on the top surface of the touch panel 30, and a transparent protective plate provided on the surface thereof 40. The step 60 provided on the surface of the transparent protective plate 40 is embedded with the transparent resin layer 31. The transparent resin layer 31 and the transparent resin layer 32 basically correspond to the adhesive layer 2 of the present embodiment.

  In the liquid crystal display device of FIG. 10, transparent resin layers 31 and 32 are interposed between the image display unit 7 and the touch panel 30 and between the touch panel 30 and the transparent protective plate 40 having a step 60. However, the transparent resin layers 31 and 32 only need to be interposed in at least one of these, and particularly when the adhesive layer 2 of the present embodiment is used, the transparent resin layers 31 and 32 are interposed between the touch panel 30 and the transparent protective plate 40 having the step 60. It is preferable to do. When the touch panel 30 is turned on, the touch panel 30 and the liquid crystal display cell 12 are integrated. As a specific example, the liquid crystal display cell 12 of the liquid crystal display device of FIG. 9 may be replaced with an on-cell.

  According to the liquid crystal display device shown in FIG. 9 and FIG. 10, since the adhesive layer 2 of this embodiment is provided as the transparent resin layer 31 or 32, it has impact resistance, has no double image, and has a clear and high contrast image. Is obtained.

  The liquid crystal display cell 12 can be made of a liquid crystal material well known in the art. Further, according to the control method of the liquid crystal material, it is classified into a TN (Twisted Nematic) method, a STN (Super-twisted nematic) method, a VA (Virtual Alignment) method, an IPS (In-Place-Switching) method, etc. Then, the liquid crystal display cell 12 using any control method may be used.

  As the polarizing plates 20 and 22, a polarizing plate common in this technical field can be used. The surfaces of the polarizing plates 20 and 22 may be subjected to treatments such as antireflection, antifouling, and hard coat. Such surface treatment may be performed on one side of the polarizing plates 20 and 22 or on both sides thereof.

  As the touch panel 30, what is generally used in this technical field can be used.

  The transparent resin layer 31 or 32 can be formed with a thickness of 0.02 mm to 3 mm, for example. In particular, in the curable resin composition of the present embodiment, it is possible to exert a more excellent effect by forming a thick film, which is preferably used when the transparent resin layer 31 or 32 having a thickness of 0.1 mm or more is formed. be able to.

  As the transparent protective plate 40, a general optical transparent substrate can be used. Specific examples thereof include inorganic plates such as glass substrates and quartz plates; plastic substrates such as acrylic resin substrates and polycarbonate plates; resin sheets such as thick polyester sheets. When high surface hardness is required, a glass substrate and an acrylic resin substrate are preferable, and a glass substrate is more preferable. The surface of these transparent protective plates 40 may be subjected to treatments such as antireflection, antifouling, and hard coat. Such surface treatment may be performed on one side of the transparent protective plate 40 or on both sides. The transparent protective plate 40 can also be used in combination of a plurality thereof.

  The backlight system 50 typically includes a reflecting unit such as a reflecting plate and an illuminating unit such as a lamp.

<Method for Manufacturing Image Display Device>
The pressure-sensitive adhesive sheet 1 is used as follows in assembling an image display device or the like. First, as shown in FIG. 11, the light release separator 4 is peeled from the pressure-sensitive adhesive sheet 1 to expose the pressure-sensitive adhesive surface 2 b of the pressure-sensitive adhesive layer 2. Subsequently, as shown in FIG. 12, the adhesive surface 2b of the adhesive layer 2 is attached to the adherend A1 and pressed by a roller R or the like. At this time, the step 60 provided on the surface of the adherend A <b> 1 is embedded by the adhesive layer 2. The adherend A1 is, for example, the image display unit 7, the transparent protective plate 40, or the touch panel 30. Subsequently, as shown in FIG. 13, the heavy release separator 3 is peeled from the adhesive layer 2 to expose the adhesive surface 2 c of the adhesive layer 2. Subsequently, as shown in FIG. 14, the adhesive surface 2 c of the adhesive layer 2 is attached to the adherend A <b> 2 and subjected to a heating and pressurizing process (autoclave process). The adherend A2 is, for example, the image display unit 7, the transparent protective plate 40, or the touch panel 30. In this way, the adherends can be bonded together via the adhesive layer 2. In addition, as for the heating and pressurizing treatment conditions at this time, the temperature is 40 ° C. to 80 ° C. and the pressure is 0.3 to 0.8 MPa, but when the step 60 on the adherend surface is 40 to 100 μm, From the viewpoint of removing more bubbles near the step, it is preferable that the temperature is 50 ° C. to 70 ° C. and the pressure is 0.4 to 0.7 MPa. The treatment time is preferably 5 to 60 minutes, and more preferably 10 to 50 minutes.

  Moreover, the said manufacturing method includes the process of irradiating an ultraviolet-ray with respect to the adhesion layer 2 from either one side of both adherends (for example, the transparent protective board 40, the touchscreen 30) before or after an autoclave process. Thereby, the reliability (reduction of bubbles and suppression of peeling) and adhesive strength under high temperature and high humidity can be further improved. From the viewpoint of further improving the reliability under high temperature and high humidity, it is preferable to irradiate ultraviolet rays from the side of the adherend (for example, the touch panel 30) that does not have the step 60.

Although there is no restriction | limiting in particular in the irradiation amount of an ultraviolet-ray, It is preferable that it is about 500-5,000mJ / cm < ² >. In addition, it is preferable to perform the process of irradiating an ultraviolet-ray after an autoclave process from a viewpoint of improving the reliability in high temperature, high humidity. In the structure thus obtained, when a glass substrate (soda lime glass) or an acrylic resin substrate is employed as an adherend, the peel strength between the adhesive layer 2 and these substrates is 5 to 30 N / 10 mm. It is preferable that it is 8-30N / 10mm, and it is further more preferable that it is 10-30N / 10mm. The peel strength can be measured as a 180 degree peel (3 seconds at a peel rate of 300 mm / min, a measurement temperature of 25 ° C.) using a tensile tester (“RTC-1210” manufactured by Orientec Co., Ltd.).

  Through the above steps, the adhesive layer 2 is disposed between the adherend A1 and the adherend A2. In particular, the adhesive layer 2 is preferably used by being disposed between the transparent protective plate 40 and the touch panel 30 or between the touch panel 30 and the image display unit 7.

  The above-described liquid crystal display device of FIG. 9 can be manufactured by obtaining a laminate by interposing the adhesive layer 2 of the present embodiment between the image display unit 7 and the transparent protective plate 40. That is, in the image display device illustrated in FIG. 9, the adhesive layer 2 of the present embodiment can be laminated on the upper surface of the polarizing plate 20 by a laminating method.

  The liquid crystal display device of FIG. 10 described above is a laminate in which the adhesive layer 2 of the present embodiment is interposed between the image display unit 7 and the touch panel 30 and / or between the touch panel 30 and the transparent protective plate 40. Can be manufactured more.

[Second Embodiment]
<Adhesive sheet for image display device>
A second embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 15 and 16, the pressure-sensitive adhesive sheet 1 for an image display device according to the present embodiment includes a film-like pressure-sensitive adhesive layer 2 and a first base material layer (light release) laminated so as to sandwich the pressure-sensitive adhesive layer 2. A separator 4) and a second substrate layer (heavy release separator 3), and a carrier layer (carrier film 5) further laminated on the second substrate layer, the first substrate layer and The outer edges 4 a and 5 a of the carrier layer protrude outward from the outer edge 2 a of the adhesive layer 2.

  That is, as shown in FIG. 15 and FIG. 16, the pressure-sensitive adhesive sheet 1 according to this embodiment includes a transparent film-like pressure-sensitive adhesive layer 2 and a light release separator 4 (first film) that is laminated so as to sandwich the pressure-sensitive adhesive layer 2. ) And a heavy release separator 3 (second base material layer), and a carrier film 5 (carrier layer) further laminated on the heavy release separator 3.

  The outer edge 5 a of the carrier film 5 projects outward from the outer edge 2 a of the adhesive layer 2. Thereby, the carrier film 5 can be easily peeled from the second base material layer by pinching the outer edge portion of the carrier film 5 protruding outward. Moreover, it is preferable that the outer edge 5 a of the carrier film 5 projects outward from the outer edge 4 a of the light release separator 4. Thereby, since the outer edge part of the carrier film 5 becomes easier to pinch, the carrier film 5 can be peeled off more easily. The amount that the outer edge 5a of the carrier film 5 protrudes from the outer edge 4a of the light release separator 4 is 0.5 mm or more and 10 mm or less from the viewpoint of ease of handling, ease of peeling, and adhesion of dust and the like. Preferably, it is 1 mm or more and 5 mm or less. When the planar shape of the carrier film 5, the adhesive layer 2, the heavy release separator 3, and the light release separator 4 is a rectangular shape such as a rectangle, the outer edge 5 a of the carrier film 5 protrudes beyond the outer edge 4 a of the light release separator 4. The amount is preferably 0.5 mm or more and 10 mm or less on at least one side, more preferably 1 mm or more and 5 mm or less on at least one side, and 0.5 mm or more and 10 mm or less on all sides. More preferably, it is particularly preferably 1 mm or more and 5 mm or less on all sides.

  Since the heavy release separator 3 is protected by the carrier film 5 until immediately before the process, the surface of the heavy release separator 3 is less damaged. Thereby, the damage | wound of the adhesion layer 2 can be visually recognized easily, and can be easily excluded before sticking the adhesion layer 2 which the damage | wound has produced on the to-be-adhered thing.

  The carrier film 5 is, for example, a polymer film such as polyethylene terephthalate, polypropylene, polyethylene, or polyester, and among them, a polyethylene terephthalate film is preferable. From the viewpoint of workability, the thickness of the carrier film 5 is preferably 15 μm or more and 100 μm or less, more preferably 20 μm or more and 80 μm or less, and further preferably 20 μm or more and 50 μm or less.

  The peel strength between the light release separator 4 and the adhesive layer 2 is lower than the peel strength between the heavy release separator 3 and the adhesive layer 2. The peel strength between the carrier film 5 and the heavy release separator 3 is lower than the peel strength between the heavy release separator 3 and the adhesive layer 2. Here, the peel strength between the carrier film 5 and the heavy release separator 3 is more preferably lower than the peel strength between the light release separator 4 and the pressure-sensitive adhesive layer 2, but even if high, the effect of the present application is impaired. There is no.

  The peel strength between the carrier film 5 and the heavy release separator 3 is adjusted by, for example, the type of adhesive layer formed between the carrier film 5 and the heavy release separator 3 and the thickness of the adhesive. Examples of the type of adhesive formed between the carrier film 5 and the heavy release separator 3 include adhesives such as acrylic adhesives. 0.1-10 micrometers is preferable and, as for the thickness of the adhesive bond layer formed between the carrier film 5 and the heavy peeling separator 3, 1-5 micrometers is more preferable.

  As described above, according to the pressure-sensitive adhesive sheet 1 of the present embodiment, the separators 3 and 4 and the carrier film 5 can be reliably peeled in a predetermined order without any defective peeling while protecting the pressure-sensitive adhesive layer 2.

<Method for producing pressure-sensitive adhesive sheet for image display device>
The adhesive sheet 1 is manufactured as follows. First, as shown in FIG. 17, a base material film 10 in which a heavy release separator 3, an adhesive layer 2, and a temporary separator 6 are sequentially laminated on a carrier film 5 is prepared. The temporary separator 6 is, for example, a layer made of the same material as the light release separator 4.

  Subsequently, the temporary separator 6, the adhesive layer 2, and the heavy release separator 3 are cut into a desired shape by a punching device (not shown) provided with the blade B. In this step, as shown in FIG. 18, it is preferable to pass the blade B through the temporary separator 6, the adhesive layer 2, and the heavy release separator 3 at a depth reaching the carrier film 5. Thereby, the notch part 5c is formed in the surface 5b by the side of the adhesion layer 2 of the carrier film 5. FIG. Thus, the adhesive layer 2 and the heavy release separator 3 can be completely cut by allowing the blade B to reach the carrier film 5 from the temporary separator 6.

  Subsequently, as shown in FIG. 19, the outer portions of the temporary separator 6, the adhesive layer 2 and the heavy release separator 3 are removed. At this time, the outer edge 3 a of the heavy release separator 3 is substantially the same as the outer edge 5 a of the carrier film 5 as shown in FIG. 20 so that the outer edge 5 a of the carrier film 5 does not protrude outward from the outer edge 3 a of the heavy release separator 3. It is preferable that they are flush. That is, only the outer part of the temporary separator 6 and the adhesive layer 2 is removed, and the outer part of the heavy release separator 3 is left on the carrier film 5 without being removed. The heavy release separator 3 after cutting is attached to the carrier film 5 as it is. It is preferable that the Thereby, the problem that the surface-exposed carrier film 5 adheres to other portions can be effectively prevented.

  After removing the outer portions of the temporary separator 6, the adhesive layer 2 and the heavy release separator 3 as shown in FIG. 19, the temporary separator 6 is subsequently released from the adhesive layer 2 as shown in FIG. A light release separator 4 is affixed to the adhesive layer 2 as shown. The pressure-sensitive adhesive sheet 1 of this embodiment is completed through the above steps. Thus, if the film is cut so that the outer edge 3a of the heavy release separator 3 is substantially flush with the outer edge 2a of the pressure-sensitive adhesive layer 2, the light release separator 4 and the heavy release separator 3 are easily peeled off. Thus, the light release separator 4 can be more easily peeled before the heavy release separator 3 is released. Further, since the outer edge 3a of the heavy release separator 3 and the outer edge 2a of the pressure-sensitive adhesive layer 2 are aligned, the position of the outer edge 2a of the pressure-sensitive adhesive layer 2 becomes clear, so that the alignment between the pressure-sensitive adhesive layer 2 and the adherend becomes easy. .

<Method for Manufacturing Image Display Device>
The pressure-sensitive adhesive sheet 1 of the present embodiment is the same as the pressure-sensitive adhesive sheet 1 of the first embodiment except that the carrier film 5 is first peeled off from the heavy release separator 3 as shown in FIG. Can be used.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not necessarily limited to the said embodiment, A various change is possible in the range which does not deviate from the summary.

  Hereinafter, the present invention will be described by way of examples. In this example, the pressure-sensitive adhesive sheet 1 according to the first embodiment and the second embodiment is produced, but the present invention is not limited to these examples.

Synthesis Example 1 (Synthesis of acrylic acid derivative polymer (A-1))
96.0 g of isostearyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name “ISTA”) and 2-hydroxy as an initial monomer in a reaction vessel equipped with a cooling tube, a thermometer, a stirring device, a dropping funnel and a nitrogen introducing tube Weigh 24.0 g of ethyl acrylate (trade name “HEA” manufactured by Osaka Organic Chemical Industry Co., Ltd.) and 150.0 g of methyl ethyl ketone, and replace the nitrogen with an air volume of 100 ml / min. Heated to ° C. Thereafter, while maintaining the temperature at 80 ° C., 24.0 g of isostearyl acrylate and 6.0 g of 2-hydroxyethyl acrylate were used as additional monomers, and t-butylperoxy-2-ethylhexanoate was added thereto. A solution in which 0 g was dissolved was prepared, and this solution was added dropwise over 120 minutes. After completion of dropping, the reaction was further continued for 2 hours.
Subsequently, methyl ethyl ketone was distilled off to obtain a copolymer resin of isostearyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 30,000).

Synthesis Example 2 (Synthesis of acrylic acid derivative polymer (A-2))
Into a reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping funnel and nitrogen introducing tube, 108.0 g of isostearyl acrylate, 12.0 g of 2-hydroxyethyl acrylate, and 150.0 g of methyl ethyl ketone were weighed as initial monomers, and 100 ml. Heating was performed from room temperature (25 ° C.) to 80 ° C. in 15 minutes while substituting nitrogen with an air volume of / min. Thereafter, while maintaining the temperature at 80 ° C., 27.0 g of isostearyl acrylate and 3.0 g of 2-hydroxyethyl acrylate were used as additional monomers, and t-butylperoxy-2-ethylhexanoate was added thereto. A solution in which 0 g was dissolved was prepared, and this solution was added dropwise over 120 minutes. After completion of dropping, the reaction was further continued for 2 hours.
Subsequently, methyl ethyl ketone was distilled off to obtain a copolymer resin of isostearyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 30,000).

Synthesis Example 3 (Synthesis of acrylic acid derivative polymer (A-3))
Weighed 96.0 g of 2-ethylhexyl acrylate, 24.0 g of 2-hydroxyethyl acrylate, and 150.0 g of methyl ethyl ketone as initial monomers in a reaction vessel equipped with a cooling pipe, thermometer, stirring device, dropping funnel and nitrogen introducing pipe, Heating was performed from room temperature (25 ° C.) to 80 ° C. in 15 minutes while purging nitrogen with an air volume of 100 ml / min. Thereafter, while maintaining the temperature at 80 ° C., 24.0 g of 2-ethylhexyl acrylate and 6.0 g of 2-hydroxyethyl acrylate were used as additional monomers, and t-butylperoxy-2-ethylhexanoate 5 A solution in which 0.0 g was dissolved was prepared, and this solution was added dropwise over 120 minutes. After completion of dropping, the reaction was further continued for 2 hours.
Subsequently, methyl ethyl ketone was distilled off to obtain a copolymer resin of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 30,000).

Synthesis Example 4 (Synthesis of side chain methacryl-modified acrylate polymer (C-1))
100.0 g of the acrylate polymer of Preparation Example 1 and 2.0 g of 2-isocyanatoethyl methacrylate in a reaction vessel equipped with a cooling tube, a thermometer, a stirrer, a dropping funnel and an oxygen introducing tube, p-methoxyphenol 0 as a polymerization inhibitor .05 g and 0.03 g of dibutyltin dilaurate as a catalyst were taken and heated from room temperature (25 ° C.) to 75 ° C. in 15 minutes while flowing air at an air volume of 100 ml / min. Then, after continuing reaction for 2 hours, maintaining temperature at 75 degreeC, as a result of performing IR measurement, the loss | disappearance of the isocyanate group was confirmed. At this point, the reaction was terminated, and a side-chain methacryl-modified acrylate polymer having a polymerizable unsaturated bond (weight average molecular weight 30,000) was obtained.
The IR measurement was performed using a Fourier transform infrared spectrophotometer (FT-710) manufactured by Horiba, Ltd.

Synthesis Example 5 (Synthesis of side chain methacryl-modified acrylate polymer (C-2))
100.0 g of the acrylate polymer of Preparation Example 2 and 2.0 g of 2-isocyanatoethyl methacrylate in a reaction vessel equipped with a cooling tube, a thermometer, a stirrer, a dropping funnel and an air introduction tube, p-methoxyphenol 0 as a polymerization inhibitor .05 g and 0.03 g of dibutyltin dilaurate as a catalyst were taken and heated from room temperature (25 ° C.) to 75 ° C. in 15 minutes while flowing air at an air volume of 100 ml / min. Then, after continuing reaction for 2 hours, maintaining temperature at 75 degreeC, as a result of performing IR measurement, the loss | disappearance of the isocyanate group was confirmed. At this point, the reaction was terminated, and a side-chain methacryl-modified acrylate polymer having a polymerizable unsaturated bond (weight average molecular weight 30,000) was obtained.

Synthesis Example 6 (Synthesis of polyurethane diacrylate (C-3))
285.3 g of polypropylene glycol (number average molecular weight 2,000), unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (manufactured by Daicel Corporation) in a reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping funnel and air inlet tube , 24.5 g of trade name “Placcel FA2D” and “Placcel” are registered trademarks), 0.13 g of p-methoxyphenol as a polymerization inhibitor and 0.5 g of dibutyltin dilaurate as a catalyst, and air at an air volume of 100 ml / min. The mixture was heated from room temperature (25 ° C.) to 75 ° C. in 15 minutes. Thereafter, while maintaining the temperature at 75 ° C., 39.6 g of isophorone diisocyanate was uniformly added dropwise over 2 hours to carry out the reaction.
After completion of the dropwise addition, the reaction was allowed to proceed for 6 hours. As a result of IR measurement, it was confirmed that the isocyanate group had disappeared, and the reaction was terminated. Polyurethane acrylate having polypropylene glycol and isophorone diisocyanate as repeating units and having (meth) acryloyl groups at both ends (weight average molecular weight 30, 000).

  The weight average molecular weight is measured using gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, and converted using a standard polystyrene calibration curve using the following equipment and measurement conditions. It is the value decided by doing. In preparing the calibration curve, a 5-sample set (PStQuick MP-H, PStQuick B [manufactured by Tosoh Corporation, trade name, “PStQuick” is a registered trademark]) was used as standard polystyrene.

Apparatus: High-speed GPC apparatus HLC-8320GPC (detector: differential refractometer, manufactured by Tosoh Corporation, trade name, “HLC” is a registered trademark)
Solvent: Tetrahydrofuran (THF)
Column: Column TSKgel SuperMultipore HZ-H (manufactured by Tosoh Corporation, trade name, “TSKgel SuperMultipore” is a registered trademark)
Column size: Column length is 150mm, column inner diameter is 4.6mm
Measurement temperature: 40 ° C
Flow rate: 0.35 ml / min Sample concentration: 10 mg / THF 5 ml
Injection volume: 20 μl

The following each component used as the raw material of an adhesive resin composition was prepared.
Component A: Acrylic acid derivative polymer (A-1) to (A-3)
B component: Isostearyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name “ISTA”)
: N-acryloyloxyethyl hexahydrophthalimide (manufactured by Toagosei Co., Ltd., trade name “M-140”)
: 2-ethylhexyl acrylate (2EHA) (manufactured by Toagosei Co., Ltd.)
: 4-hydroxybutyl acrylate (4HBA) (manufactured by Nippon Kasei Co., Ltd.)
Component C: Side chain methacryl-modified acrylate polymers (C-1) to (C-2)
: Polyurethane diacrylate (C-3)
: 1,9-nonanediol diacrylate (C-4, manufactured by Kyoeisha Chemical Co., Ltd.)
D component: 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF Japan Ltd., trade names “Irgacure-184” and “IRGACURE” are registered trademarks, hereinafter I-184)

<Example 1>
[Preparation of adhesive sheet A (three-layer product)]
Using polyethylene terephthalate having a thickness of 75 μm (made by Fujimori Kogyo Co., Ltd.) as the heavy release separator 3 and polyethylene terephthalate having a thickness of 50 μm (made by Fujimori Kogyo Co., Ltd.) as the light release separator 4 and the temporary separator 6, the following (I) to A pressure-sensitive adhesive sheet A1 was produced by the procedure (VI).

(I) Acrylic acid derivative polymer (A-1) 60 g, isostearyl acrylate (ISTA) 30.9 g, N-acryloyloxyethyl hexahydrophthalimide (M-140) 3.0 g, 4-hydroxybutyl acrylate (4HBA) 5.0 g, 4.0 g of side chain methacryl-modified acrylate polymer (C-1) and 0.1 g of 1-hydroxycyclohexyl phenyl ketone (I-184) are weighed and mixed together by stirring to obtain a liquid adhesive at room temperature. A functional resin composition was obtained.

(II) After coating this adhesive resin composition on the heavy release separator 3 to form a coating film, a temporary separator 6 is laminated on the adhesive layer 2, and an ultraviolet irradiation device (manufactured by Eye Graphics Co., Ltd.). Was used to irradiate ultraviolet rays (400 mJ / cm ² ) to obtain an adhesive sheet A1 in which the adhesive layer 2 was sandwiched between the heavy release separator 3 and the temporary separator 6. The adhesive layer 2 was coated by adjusting the thickness to 150 μm.

(III) The heavy release separator 3, the adhesive layer 2, and the temporary separator 6 were cut with a rotary blade having a diameter of 72 mm so as to be 220 mm × 180 mm.

(IV) The adhesive layer 2 and the temporary separator 6 were cut with a rotary blade having a diameter of 72 mm so as to be 205 mm × 160 mm. At this time, both sides on the long side of the heavy release separator 3 protrude 7.5 mm from both sides on the long side of the adhesive layer 2, and both sides on the short side of the heavy release separator 3 are adhesive layer 2. It cut | disconnected so that 5 mm might protrude from both sides of the short side. The cutting of (III) and (IV) was performed using a rotary punching device.

(V) The temporary separator 6 was peeled off, and a 215 mm × 170 mm light release separator 4 was laminated on the adhesive layer 2. In this way, an adhesive sheet A1 was obtained. At this time, both sides on the long side of the light release separator 4 protrude 5 mm from both sides on the long side of the adhesive layer 2, and both sides on the short side of the light release separator 4 are short sides of the adhesive layer 2. Lamination was carried out so as to protrude 5 mm from both sides.

<Examples 2 to 8 and Comparative Example 1>
A pressure-sensitive adhesive sheet A1 was obtained in the same manner as in Example 1 except that the blending conditions and exposure amount were blended as shown in Table 1.

[Various evaluations]
The following (1)-(6) was evaluated about adhesive sheet A1 obtained by each Example and the comparative example.

(1) Measurement of glass transition temperature (Tg), shear storage elastic modulus, loss elastic modulus and tan δ Three adhesive layers 2 having a thickness of 150 μm obtained in the above procedure (II) were stacked to a thickness of about 450 μm, A sample was prepared by cutting to a width of 10 mm and a length of 10 mm. Two samples were prepared, and as shown in FIG. 24, the sample S was sandwiched between the plate P1 at both ends and the center plate P2 using a jig 100 to obtain a measurement sample. And the glass transition temperature (Tg), the shear storage elastic modulus, the loss elastic modulus, and tanδ of the sample were measured using a wide-range dynamic viscoelasticity measuring device (Solids Analyzer RSA-II manufactured by Rheometric Scientific). The measurement conditions were “shear sandwich mode, frequency 1.0 Hz, measurement temperature range −20 to 100 ° C., temperature increase rate 5 ° C./min”.

(2) Level difference embedding The produced pressure-sensitive adhesive sheet A1 was cut into dimensions of 50 mm in width and 80 mm in length, and a cycloolefin polymer film of 56 mm × 86 mm × 0.1 mm (thickness) (trade name “Zeonor” manufactured by Nippon Zeon Co., Ltd.). Film ZF16 "and" Zeonor "are registered trademarks)) (25 ° C., load: 500 gf (4.9 N)) using a hand roller. Next, 56 mm (width) x 86 mm (length) provided with a printing layer (step 60) having a width of 9 mm and a thickness of 0.08 mm on the other adhesive material side to which the cycloolefin polymer film is not bonded. A glass substrate having a size of 0.7 mm (thickness) is placed at 60 ° C., 0.5 MPa, and a degree of vacuum using a vacuum bonding apparatus (manufactured by Takatori Co., Ltd., trade name “TPL-0512MH”) so as to sandwich the adhesive material. Bonding was performed for 60 seconds under the condition of 50 Pa. Thereafter, autoclaving (45 ° C., 0.5 MPa) was performed for 10 minutes, and then ultraviolet rays were irradiated at 2,000 mJ / cm ² using an ultraviolet irradiation device (manufactured by Eye Graphics Co., Ltd.) to obtain an evaluation sample.
Using the evaluation sample, appearance evaluation (bubbles, peeling) around the printed layer (step 60) was performed with an optical microscope, and step embedding was determined according to the following evaluation criteria.
(Evaluation criteria)
A: No bubbles and no peeling.
B: There are bubbles or peeling only on one side.
C: There are bubbles or peeling on two or more sides.

(3) Bubble resistance An evaluation sample was prepared in the same manner as in (2). After confirming the bubbles visually, the prepared evaluation sample was put into an 85 ° C. oven and left for 12 hours. After leaving, bubbles newly generated on the substrate were visually confirmed.
(Evaluation criteria)
A: No bubbles are generated.
B: 1-5 occurrences.
C: 5 or more occurred.

(4) Surface flatness The prepared pressure-sensitive adhesive sheet was cut into a width of 50 mm and a length of 80 mm, and a cycloolefin polymer film of 56 mm × 86 mm × 0.1 mm (thickness) was used with a hand roller (25 ° C., load) : 500 gf (4.9 N)). Next, 56 mm (width) x 86 mm (length) provided with a printing layer (step 60) having a width of 9 mm and a thickness of 0.08 mm on the other adhesive material side to which the cycloolefin polymer film is not bonded. A glass substrate having a size of 0.7 mm (thickness) was bonded for 60 seconds under the conditions of 60 ° C., 0.5 MPa, and a degree of vacuum of 50 Pa using a vacuum bonding apparatus so as to sandwich the adhesive material. Thereafter, autoclaving (45 ° C., 0.5 MPa) was performed for 10 minutes, and then an ultraviolet ray was irradiated at 2,000 mJ / cm ² using an ultraviolet irradiation device to obtain an evaluation sample.

Using the evaluation sample, the surface shape of the periphery of the printed layer (step 60) on the cycloolefin polymer film side was measured under the following conditions using a surface roughness measuring machine (trade name “SE3500” manufactured by Kosaka Laboratory Ltd.). It was measured.
(Surface shape measurement conditions)
Tip shape of probe (diamond material): Conical tip radius: 2 μm
Vertical angle: 60 °
Measuring speed: 0.15 mm / sec Measuring force: 0.75 mN
Cut-off value: 0.8mm
Standard length: 0.8mm
Evaluation length: 10mm

The measurement was performed continuously on the printed layer surface 5 mm and the unprinted portion surface 5 mm, and the surface flatness was determined from the measured value difference (Δt) between the printed layer surface and the unprinted portion surface according to the following evaluation criteria.
(Evaluation criteria)
A: 20 μm or less B: 20-40 μm
C: 40 μm or more

(5) Exudation property The prepared adhesive sheet was cut into a size of 50 mm in width and 80 mm in length, and a hand roller was applied to a cycloolefin polymer film of 56 mm (width) × 86 mm (length) × 0.1 mm (thickness). Using (25 ° C., load: 500 gf (4.9 N)), the diagonal length of the adhesive sheet portion was measured. Next, 56 mm (width) x 86 mm (length) provided with a printing layer (step 60) having a width of 9 mm and a thickness of 0.08 mm on the other adhesive material side to which the cycloolefin polymer film is not bonded. A glass substrate having a size of × 0.7 mm (thickness) is pasted for 60 seconds under the conditions of 60 ° C., 0.5 MPa, and a degree of vacuum of 50 Pa using a vacuum laminating apparatus so as to sandwich the adhesive material, and at 25 ° C. for 30 minutes. It was set as the evaluation sample after leaving still.
The diagonal length of the adhesive sheet portion of the evaluation sample was measured, and in accordance with the following evaluation criteria, the bleeding property was determined from the amount of change (increase) in the diagonal length of the adhesive sheet portion before and after bonding to the glass substrate. .
(Evaluation criteria)
A: 1.5 mm or less B: 1.5-3 mm
C: 3 mm or more

(6) Optical characteristics The produced adhesive material sheet was cut into dimensions of 40 mm in width and 100 mm in length, and the glass substrate (soda lime glass) having dimensions of 50 mm (width) × 100 mm (length) × 3 mm (thickness) The polyethylene terephthalate film on one side of the pressure-sensitive adhesive sheet was peeled off and bonded using a hand roller (25 ° C., load: 500 gf (4.9 N)). Subsequently, the polyethylene terephthalate film on the opposite surface of the adhesive material sheet was peeled off, and the adhesive material surface was measured as the light source side.
(I) Measurement of L *, a *, and b * Measurement was performed using a spectrocolorimeter (manufactured by Nippon Denshoku Industries Co., Ltd., SQ-2000).
(Ii) Measurement of turbidity (haze) The produced pressure-sensitive adhesive sheet was cut into dimensions of 40 mm in width and 100 mm in length, the polyethylene terephthalate film on one side of the pressure-sensitive adhesive sheet was peeled off, and 50 mm (width) x 100 mm (length) A glass substrate (soda lime glass) having a size of 3 mm (thickness) was bonded using a hand roller (25 ° C., load: 500 g (4.9 N)). Next, the polyethylene terephthalate film on the opposite side of the pressure-sensitive adhesive sheet is peeled off, and the pressure-sensitive adhesive layer surface is used as a light source side, using a turbidimeter (trade name “NDH-5000”, manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K 7136. Measured.
Haze (%) = (Td / Tt) × 100
Td: diffuse transmittance Tt: total light transmittance

(7) Dielectric constant measurement After irradiating the prepared adhesive sheet with 2000 mJ / cm ^{2 of} ultraviolet rays using an ultraviolet irradiation apparatus, the adhesive sheet was cut into dimensions of 50 mm in width and 50 mm in length, and polyethylene terephthalate on one side of the adhesive sheet was Peel off the adhesive sheet so that the glossy side of the copper foil (trade name “SLP-18”, manufactured by Nippon Electrolytic Co., Ltd.) with dimensions of 100 mm (width) × 100 mm (length) × 18 μm (thickness) does not protrude. Pasted together. Next, the other polyethylene terephthalate of the pressure-sensitive adhesive sheet is peeled off, and a copper foil having a size of 20 mm (width) × 20 mm (length) × 18 μm (thickness) (trade name “SLP-18” manufactured by Nippon Electrolytic Co., Ltd.) The glossy side was laminated so that the adhesive sheet did not protrude. A terminal is brought into contact with a substantially central portion of a copper foil having a size of 100 mm (width) × 100 mm (length) and a copper foil having a size of 20 mm (width) × 20 mm (length), and a dielectric constant measuring device (Agilent Technologies) The capacitance (C) was measured under the conditions of 25 ° C. and a frequency of 100 kHz using an LCR meter E4980 (manufactured by LCR meter E4980), and the dielectric constant ε _r was determined by substituting it into the following equation. Here, ε ₀ is the dielectric constant of vacuum, and d is the thickness of the adhesive layer 2.
C = ε ₀ × ε _r × (20 mm × 20 mm) / d

  The evaluation results of each example and comparative example are shown in Table 1.

<Example 9>
[Preparation of adhesive sheet B (4-layer product)]
(I) A liquid adhesive resin composition was obtained in the same manner as in Example 1.
(II) After coating this adhesive resin composition on one side of the heavy release separator 3 to form a coating film, the temporary separator 6 is laminated on the adhesive layer 2 and irradiated with ultraviolet rays (200 mJ / cm ² ) After that, an acrylic adhesive (Hitalex K-6040 (trade name), manufactured by Hitachi Chemical Co., Ltd., “Hitalex” is a registered trademark) is laminated on the other surface of the heavy release separator 3. A carrier film 5 was laminated thereon.
(III) The heavy release separator 3, the adhesive layer 2, the temporary separator 6 and the carrier film 5 were cut so as to be 220 mm × 180 mm.
(IV) The pressure-sensitive adhesive layer 2, the heavy release separator 3 and the temporary separator 6 were cut with a rotary blade having a diameter of 72 mm so as to be 205 mm × 160 mm. A rotary punching device was used for cutting. At this time, both long sides of the carrier film 5 protrude 7.5 mm from both long sides of the adhesive layer 2, and both short sides of the carrier film 5 are short of the adhesive layer 2. It cut | disconnected so that 5 mm might protrude from both sides of a side.
(V) The temporary separator 6 was peeled off, and a 215 mm × 170 mm light release separator 4 was laminated on the adhesive layer 2. In this way, an adhesive sheet B1 was obtained. At this time, both sides on the long side of the light release separator 4 protrude 5 mm from both sides on the long side of the adhesive layer 2, and both sides on the short side of the light release separator 4 are short sides of the adhesive layer 2. Lamination was carried out so as to protrude 5 mm from both sides.

  As a result of performing the same evaluation as described above for the pressure-sensitive adhesive sheet B1, a pressure-sensitive adhesive sheet B1 having a desired shape can be produced, and the results are excellent in step embedding property, bubble resistance, and appearance as in Example 1. It became.

  According to the present invention, it is possible to manufacture an adhesive sheet 1 for an image display device including an adhesive layer 2 that is excellent in transparency, handleability, step embedding property, and bubble resistance. Moreover, the adhesion force and holding | maintenance force of adhesion layer 2 itself can be improved by accelerating | stimulating the crosslinking reaction of adhesion layer 2 after bonding a base material etc. Since a device in which such an adhesive layer 2 is incorporated exhibits high reliability, the adhesive sheet 1 of the present invention is suitable for use in an image display apparatus. In particular, it is extremely useful as a sheet material used when filling a space between an information input device such as the touch panel 30 and the transparent protective plate 40.

  DESCRIPTION OF SYMBOLS 1 ... Adhesive sheet, 2 ... Adhesive layer, 3 ... Heavy release separator, 4 ... Light release separator, 5 ... Carrier film, 6 ... Temporary separator, 2a, 3a, 4a ... Outer edge, 3b ... Adhesive layer side surface, 3c ... Cut portion, 10 ... base material film, B ... blade, 40 ... transparent protective plate (glass or plastic substrate), 7 ... image display unit, 12 ... liquid crystal display cell, 20, 22 ... polarizing plate, 30 ... touch panel, 31 32 ... Transparent resin layer, 50 ... Backlight system, 60 ... Step, 100 ... Jig.

Claims (5)

An adhesive layer, and a pair of base material layers laminated so as to sandwich the adhesive layer,
The pressure-sensitive adhesive layer includes a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 4 to 18 carbon atoms and a structural unit derived from N- (meth) acryloyloxyethyl hexahydrophthalimide. A pressure-sensitive adhesive sheet for an image display device, having a shear storage elastic modulus at 25 ° C. of 30 kPa to 150 kPa. An adhesive layer, first and second base material layers laminated so as to sandwich the adhesive layer, and a carrier layer further laminated on the second base material layer,
The pressure-sensitive adhesive layer includes a structural unit derived from an alkyl (meth) acrylate having an alkyl group having 4 to 18 carbon atoms and a structural unit derived from N- (meth) acryloyloxyethyl hexahydrophthalimide. A pressure-sensitive adhesive sheet for an image display device, having a shear storage elastic modulus at 25 ° C. of 30 kPa to 150 kPa. The process of bonding adherends together and obtaining a layered product through the pressure-sensitive adhesive layer provided in the pressure-sensitive adhesive sheet for an image display device according to claim 1 or 2, and
A step of subjecting the laminate to heat and pressure treatment under conditions of 40 ° C. to 80 ° C. and 0.3 to 0.8 MPa;
Irradiating the laminate with ultraviolet rays from any one side of the adherend, and
Manufacturing method of image display apparatus.   The method for manufacturing an image display device according to claim 3, wherein the adherend is a transparent protective plate and a touch panel.   An image display device manufactured by the method according to claim 3.

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