JP2015224320A - Tackifying adhesive sheet, article, and method for manufacturing article and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tackifying adhesive sheet in which bubbles do not remain on a boundary surface between a step part of an adherend and a tackifier layer, and a tackifier component does not ooze out from a roll end part when winding the sheet into a roll.SOLUTION: A tackifying adhesive sheet includes an adhesive layer (A), and a tackifier layer (B) laminated together where the elastic modulus (G') of the adhesive layer (A) measured at a temperature of 40°C by a frequency of 1.0 Hz is not less than 1.0×10Pa, the elastic modulus (G') of the adhesive layer (A) measured at a temperature of 70°C by a frequency of 1 Hz is less than 1.0×10Pa, the elastic modulus (G') of the tackifier layer (B) measured at a temperature of 40°C by a frequency of 1.0 Hz is not less than 1.0×10Pa, and the elastic modulus (G') of the tackifier layer (B) measured at a temperature of 70°C by a frequency of 1 Hz is not less than 1.0×10Pa.

Description

  The present invention relates to an adhesive sheet that can be used in various applications including optical applications.

  As an image display device provided in a small electronic terminal such as an electronic notebook or a mobile phone, a transparent image display panel is generally laminated on the upper or lower portion of the image display module for the purpose of protecting the image display module. Is known.

  In many cases, the image display panel is usually provided with a decorative layer for the purpose of providing design properties or light shielding properties.

  However, since a slight step is formed with respect to the surface of the image display panel at the place where the decorative layer is provided, the image display panel is fixed to the image display module using an adhesive sheet or the like. In some cases, the adhesive sheet cannot follow the stepped portion, and bubbles may be included in the interface between the adhesive sheet and the stepped portion.

  As an adhesive sheet that can follow the stepped portion and does not easily contain bubbles at the interface, for example, an acid obtained by copolymerizing a monomer containing a specific amount of an alkoxy (meth) acrylate and a monomer having a crosslinkable functional group A main acrylic polymer having a specific weight average molecular weight substantially free of a group, a low molecular weight (meth) acrylic polymer having a hydrogen bonding functional group and substantially no acidic group, and an isocyanate crosslinking agent There is known a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer having a thickness of 10 to 1000 μm formed using a pressure-sensitive adhesive containing a specific ratio of (see, for example, Patent Document 1).

  However, with the diversification of the design of the small electronic terminals and the like, the decorative layer tends to become thicker, and in the adhesive sheet, the step portion formed by the thick decorative layer In some cases, it was not possible to sufficiently follow, and air bubbles were included in the interface between the stepped portion and the adhesive sheet.

  In general, it is considered preferable to use a sheet having a relatively flexible adhesive layer as an adhesive sheet having excellent step following ability.

  However, in the adhesive sheet simply excellent in flexibility, very fine bubbles may still remain in the interface and the adhesive layer.

  In addition, when the flexible adhesive sheet is stored in a state where it is wound around a roll or the like via a release paper or the like, a part of the pressure-sensitive adhesive layer is pushed out from the end of the roll, etc. There were cases where handling when unwinding was not easy. In addition, the adhesive sheet in which a part of the pressure-sensitive adhesive layer is extruded from the end of a roll or the like is not sufficient in the followability to the stepped portion, and bubbles remain in the interface or the pressure-sensitive adhesive layer. There was a case.

JP 2013-001769 A

  Even if the problem to be solved by the present invention is affixed to the surface of an adherend having a stepped portion, the interface between the stepped portion and the pressure-sensitive adhesive layer, and minute bubbles in the pressure-sensitive adhesive layer Is to provide an adhesive sheet capable of preventing the pressure-sensitive adhesive component from being pushed out from the end of the roll even when it is wound around a roll or the like.

  The present inventors have found that the above problem can be solved by using an adhesive sheet in which the adhesive layer (A) having the specific storage elastic modulus and the adhesive layer (B) are laminated. .

That is, the present invention is an adhesive sheet in which an adhesive layer (A) and an adhesive layer (B) are laminated, and the adhesive layer (A) was measured at a temperature of 40 ° C. and a frequency of 1.0 Hz. A storage elastic modulus (G ′ _a40 ) of 1.0 × 10 ⁴ Pa or more and a storage elastic modulus (G ′ _a70 ) measured at a temperature of 70 ° C. and a frequency of 1 Hz of the adhesive layer (A) is 1. A storage elastic modulus (G ′ _b40 ) measured at a temperature of 40 ° C. and a frequency of 1.0 Hz of the pressure-sensitive adhesive layer (B) is 1.0 × 10 ⁴ Pa or more, and less than 0 × 10 ⁴ Pa; The pressure-sensitive adhesive layer (B) has a storage elastic modulus (G ′ _b70 ) measured at a temperature of 70 ° C. and a frequency of 1 Hz of 1.0 × 10 ⁴ Pa or more.

  Even when the adhesive sheet of the present invention is affixed to the surface of an adherend having a stepped portion, the interface between the stepped portion and the pressure-sensitive adhesive layer, and minute bubbles are present in the pressure-sensitive adhesive layer. Since it is possible to prevent the pressure-sensitive adhesive component from being pushed out from the end of the roll without remaining, even when wound on a roll or the like, for example, a liquid crystal display device, a touch panel module, an organic EL display device It can be used for the manufacture of etc.

It is a conceptual diagram which shows an example of the embodiment of the adhesive sheet | seat of this invention.

The adhesive sheet of the present invention is an adhesive sheet in which an adhesive layer (A) and an adhesive layer (B) are laminated, and the adhesive layer (A) has a temperature of 40 ° C. and a frequency of 1.0 Hz. in the measured storage modulus (G _'a40) is not less 1.0 × ¹⁰ 4 Pa or more and a storage modulus measured at a temperature 70 ° C. and a frequency 1Hz of the adhesive layer (a) (G' _a70) Is less than 1.0 × 10 ⁴ Pa, and the storage elastic modulus (G ′ _b40 ) of the pressure-sensitive adhesive layer (B) measured at a temperature of 40 ° C. and a frequency of 1.0 Hz is 1.0 × 10 ⁴ Pa or more. And the storage elastic modulus ( _G'b70 ) measured at the temperature of 70 _degreeC and the frequency of 1 Hz of the said adhesive layer (B) is 1.0 * 10 < ⁴ > Pa or more, It is characterized by the above-mentioned.

  If it is the said adhesive sheet, even if it is a case where it winds up to a roll etc., it can prevent that an adhesive bond layer (A) and an adhesive layer (B) are extruded from the edge part of a roll, and It becomes possible to follow the stepped portion on the surface of the transparent substrate due to the thickness of the decorative layer.

Examples of the adhesive sheet of the present invention include those in which the adhesive layer (A) and the pressure-sensitive adhesive layer (B) are sequentially laminated. Each of the adhesive layer (A) and the pressure-sensitive adhesive layer (B) may be a single layer, or may be a laminate of two or more layers that are the same or different.
Moreover, as an adhesive sheet | seat of this invention, what was laminated | stacked in order of the said adhesive layer (B) / adhesive layer (A) / adhesive layer (B), for example can also be used. The adhesive sheet having such a configuration prevents the minute bubbles from remaining in the interface between the stepped portion and the pressure-sensitive adhesive layer (B) and the pressure-sensitive adhesive layer (B), and rolls, etc. Since it is possible to further prevent some of the adhesive layer (A) and the pressure-sensitive adhesive layer (B) from being rolled up, it is preferable.

  Moreover, as the adhesive sheet | seat of this invention, the to-be-adhered body (C) which has the level | step-difference part mentioned later on the surface of the said adhesive layer (B) may be affixed previously.

  First, the adhesive layer (A) constituting the adhesive sheet of the present invention will be described.

As the adhesive layer (A), when the adhesive sheet is attached to the surface of the adherend (C) having a stepped portion, the interface between the stepped portion and the pressure-sensitive adhesive layer (B), and Even when the microbubbles do not remain in the pressure-sensitive adhesive layer (B) and the film is wound on a roll or the like, a part of the adhesive layer (A) or the pressure-sensitive adhesive layer (B) is the end of the roll. Storage modulus (G ′ _a40 ) measured at a temperature of 40 ° C. and a frequency of 1.0 Hz is 1.0 × 10 ⁴ Pa or more in order to obtain an adhesive sheet that can be prevented from being extruded from the part, and A storage elastic modulus (G ′ _a70 ) measured at a temperature of 70 ° C. and a frequency of 1 Hz is less than 1.0 × 10 ⁴ Pa.

The adhesive layer (A) has a storage elastic modulus (G ′ _a40 ) in the range of 1.0 × 10 ⁴ Pa to 1.0 × 10 ⁶ and a storage elastic modulus (G ′ _a70 ). It is preferable to use a material having a range of 1.0 × 10 ¹ Pa to less than 1.0 × 10 ⁴ Pa, and the storage elastic modulus (G ′ _a40 ) is 1.0 × 10 ⁴ Pa to 1.0 ×. It is in the range of 10 ⁶ and the storage elastic modulus (G ′ _a70 ) is in the range of 1.0 × 10 ¹ Pa to less than 1.0 × 10 ² Pa. Since it can suppress that a micro bubble remains in an interface with an agent layer (B) and the said adhesive layer (B), it is more preferable.

The storage elastic modulus (G ′ _a40 ) at 40 ° C. and the storage elastic modulus (G ′ _a70 ) at 70 ° C. were _{measured using} a viscoelasticity tester (trade name: Ares 2KSTD, manufactured by Rheometrics). It can be obtained by sandwiching a test piece between parallel disks, which are the measurement parts, and measuring the storage elastic modulus and loss elastic modulus at a temperature of 40 ° C. or 70 ° C. and a frequency of 1 Hz. In addition, as a test piece used by the said measurement, what cut | judged the said adhesive bond layer (A) in the circular shape which consists of a 1 mm thickness and a diameter of 8 mm is used.

The storage elastic modulus (G ′ _a40 ) and the storage elastic modulus (G ′ _a70 ) are predetermined by using, for example, a component containing polyurethane (a1) as a component constituting the adhesive layer (A). It can adjust suitably in the range. Specifically, the storage elastic modulus can be easily adjusted to a predetermined range by appropriately selecting, for example, the composition and number average molecular weight of the polyol (a1-1) constituting the polyurethane (a1).

The adhesive layer (A) is irradiated with an active energy ray or the like, so that the storage elastic modulus (G ′ _a′40 ) measured at a temperature of 40 ° C. and a frequency of 1.0 Hz is 1.0 × 10 ^4. An adhesive layer (A ′) having a storage elastic modulus (G ′ _a′70 ) of 1.0 × 10 ⁴ Pa or more measured at a temperature of 70 ° C. and a frequency of 1 Hz is formed. The adhesive layer (A ′) is formed on the adhesive sheet and the adherend (C) without impairing the hardness of the surface of the adhesive sheet attached to the surface of the adherend (C) described later. It is preferable for imparting adhesiveness at a level that does not cause peeling with time.

The storage elastic modulus (G ′ _a′40 ) of the adhesive layer (A ′) was 1.0 × 10 ⁴ Pa to 1.0 × 10 ⁷ Pa, measured at a temperature of 70 ° C. and a frequency of 1 Hz. It is preferable that the storage elastic modulus (G ′ _a′70 ) is 1.0 × 10 ⁴ Pa to 1.0 × 10 ⁷ Pa.

  The adhesive layer (A) can be formed, for example, by applying an adhesive composition to the surface of a release liner or the like and drying.

  As said adhesive composition, what can form the adhesive bond layer which has the said predetermined storage elastic modulus can be used. Specifically, as the adhesive composition, an adhesive composition containing polyurethane (a1) having a polymerizable unsaturated double bond can be used.

  As the polyurethane (a1), a cured product (adhesive layer (A ′)) can be formed by, for example, irradiation with active energy rays to promote radical polymerization due to the polymerizable unsaturated double bond. Is preferably used.

  Examples of the polyurethane (a1) include a polyurethane (a ′) having an isocyanate group or a hydroxyl group obtained by reacting a polyol (a1-1) and a polyisocyanate (a1-2), and the hydroxyl group or isocyanate group. What can be obtained by making it react with the (meth) acryl monomer which has a functional group which can react with can be used.

  As the polyol (a1-1) that can be used for the production of the polyurethane (a1), polycarbonate polyol, polyester polyol, polyether polyol, and the like can be used. Especially, as said polyol (a1-1), it is preferable to use a polycarbonate polyol and a polyester polyol individually or in combination of 2 or more types, and it is a level which can be used for an optical use that a polycarbonate polyol and a polyester polyol are used in combination. The transparency of the adherend (C), the interface between the stepped portion and the pressure-sensitive adhesive layer (B) by having a better followability to the surface having the stepped portion of the adherend (C), and Prevents minute bubbles from remaining in the pressure-sensitive adhesive layer (B), and further protrudes part of the adhesive layer (A) and pressure-sensitive adhesive layer (B) when wound on a roll or the like. Since it can prevent, it is preferable.

  As said polycarbonate polyol, what is obtained by making carbonate ester and / or phosgene react with the low molecular polyol mentioned later, for example can be used.

  As the carbonate ester, for example, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate and the like can be used.

  Examples of the low molecular polyol that can react with the carbonate ester or phosgene include, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene, and the like. Propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexane Diol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol 2-methyl-1,3-propanediol Neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octane Diol, 1,4-cyclohexanedimethanol, hydroquinone, resorcin, bisphenol A, bisphenol F, 4,4′-biphenol, and the like can be used.

  As the polycarbonate polyol, an aliphatic polycarbonate polyol or an alicyclic polycarbonate polyol is preferably used.

  Examples of the aliphatic polycarbonate polyol include dialkyl carbonate, 1,2-propanediol, 1,4-butanediol, 1 to provide the adhesive sheet with a level of transparency that can be used for optical applications, for example. , 5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol are preferably used by reacting with one or more polyols selected from the group consisting of 1,6-hexanediol.

  As the alicyclic polycarbonate polyol, for example, dialkyl carbonate and cyclohexane dimethanol are used to give the adhesive sheet a level of transparency that can be used, for example, in optical applications, and excellent initial cohesion. And those obtained by reacting with a polyol containing one or more selected from the group consisting of derivatives thereof.

  As the polycarbonate polyol, an adhesive sheet having a storage elastic modulus within the predetermined range is formed. As a result, a level of transparency usable for optical applications can be maintained, and the adherend (C) Microbubbles remain in the interface between the stepped portion and the pressure-sensitive adhesive layer (B) and in the pressure-sensitive adhesive layer (B) by providing more excellent followability to the surface having the stepped portion. In order to obtain an adhesive sheet that can further prevent some of the adhesive layer (A) and the pressure-sensitive adhesive layer (B) from protruding when wound on a roll or the like, Those having a number average molecular weight are preferably used, more preferably those having a number average molecular weight in the range of 1000 to 5000, and more preferably those having a number average molecular weight in the range of 1000 to 3000. The Preferred.

  The polycarbonate polyol is preferably used in the range of 40% by mass to 90% by mass with respect to the total amount of the polyol (a1-1), and is preferably used in the range of 60% by mass to 80% by mass. The level of transparency that can be used for the surface of the adherend (C) can be maintained, and the surface having the stepped portion of the adherend (C) has more excellent followability so that the stepped portion and the adhesive layer (B) Prevents minute bubbles from remaining in the interface and the pressure-sensitive adhesive layer (B), and partially protrudes the adhesive layer (A) and the pressure-sensitive adhesive layer (B) when wound on a roll or the like. Can be further prevented.

  Examples of the polyester polyol that can be used for the polyol (a1-1) include those obtained by esterifying low molecular weight polyols and polycarboxylic acids, and ring-opening polymerization reactions of cyclic ester compounds such as ε-caprolactone. Polyesters obtained by the above, copolymerized polyesters thereof, and the like can be used.

  Examples of the low molecular weight polyol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, and 1,3- Aliphatic alkylene glycols such as butanediol, cyclohexanedimethanol and the like can be used.

  Examples of the polycarboxylic acid that can be used in the production of the polyester polyol include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, and naphthalene dicarboxylic acid. Aromatic dicarboxylic acids such as acids, and anhydrides or esterified products thereof can be used.

  As said polyester polyol, the adhesive sheet | seat provided with the storage elastic modulus in the said predetermined range is obtained, As a result, the much more followable | trackability with respect to the surface which has the level | step-difference part of the said to-be-adhered body (C). By providing, the interface between the stepped portion and the pressure-sensitive adhesive layer (B) and the microbubbles are prevented from remaining in the pressure-sensitive adhesive layer (B), and the adhesive layer when wound on a roll or the like It is preferable to use an aliphatic polyester polyol, and a linear aliphatic polyester polyol is used in order to obtain a pressure-sensitive adhesive sheet that can further prevent some protrusion of (A) and the pressure-sensitive adhesive layer (B). It is more preferable. The said linear aliphatic polyester polyol refers to the polyester polyol which does not have an alkyl group in a side chain.

  Examples of the polyester polyol include those obtained by reacting the aliphatic alkylene glycol with an aliphatic dicarboxylic acid. For example, an aliphatic polyester polyol obtained by an esterification reaction of polypropylene glycol and adipic acid is used. It is preferable.

  As the polyester polyol, an adhesive sheet having a storage elastic modulus within the predetermined range can be formed, and as a result, the surface of the adherend (C) having a stepped portion is more excellent. When it is wound up on a roll or the like, it prevents the formation of minute bubbles in the interface between the stepped portion and the pressure-sensitive adhesive layer (B) and the pressure-sensitive adhesive layer (B). In order to obtain an adhesive sheet that can further prevent some of the adhesive layer (A) and the pressure-sensitive adhesive layer (B) from protruding, use one having a number average molecular weight in the range of 1000 to 5000 Is preferred.

  The polyester polyol is preferably used in the range of 10% by mass to 50% by mass with respect to the total amount of the polyol (a1-1), and is preferably used in the range of 20% by mass to 40% by mass. The level of transparency that can be used for the surface of the adherend (C) can be maintained, and the surface having the stepped portion of the adherend (C) has more excellent followability so that the stepped portion and the adhesive layer (B) Prevents minute bubbles from remaining in the interface and the pressure-sensitive adhesive layer (B), and partially protrudes the adhesive layer (A) and the pressure-sensitive adhesive layer (B) when wound on a roll or the like. Can be further prevented.

In particular, when the polyester polyol obtained by reacting an adipic acid with an aliphatic diol such as 1,2-ethanediol or 1,4-butanediol is used as the polyester polyol, for example, 1100 to 2900. It is preferable to use those having a number average molecular weight in the range of 1, and in the case of using a polyester polyol obtained by reacting 1,6-hexanediol and adipic acid, the number average molecular weight in the range of 1100 to 5000 Even if it has a good transparency and is attached to the surface of the adherend having a stepped portion, the interface between the stepped portion and the pressure-sensitive adhesive layer, and Even if the microbubbles do not remain in the pressure-sensitive adhesive layer and are wound around a roll or the like, the pressure-sensitive adhesive component is the end of the roll. Particularly preferable for obtaining the adhesive sheet capable of preventing the extruded.
Moreover, when using the polyester polyol obtained by reacting 1,6-hexanediol and sebacic acid as the polyester polyol, it is possible to use one having a number average molecular weight in the range of 1000 to 5000. The interface between the stepped portion and the pressure-sensitive adhesive layer, and the microbubbles do not remain in the pressure-sensitive adhesive layer, and even when the pressure-sensitive adhesive component is wound on a roll or the like, the pressure-sensitive adhesive component is removed from the end of the roll. It is preferable for obtaining an adhesive sheet that can be further prevented from being extruded.

  As the polyol (a1-1), it is preferable to use a combination of the polycarbonate polyol and the polyester polyol.

  As for the said polycarbonate polyol and the said polyester polyol, it is preferable to use what contains a total of 20 mass parts or more with respect to 100 mass parts of the said polyol (a1-1), and uses what contains 50 mass parts or more. Is capable of maintaining a level of transparency that can be used for optical applications, and has better followability with respect to the surface of the adherend (C) having a stepped portion, whereby the stepped portion and the pressure-sensitive adhesive layer The adhesive layer (A) and the pressure-sensitive adhesive layer (B) at the time of winding on a roll or the like, preventing the minute bubbles from remaining in the interface with (B) and the pressure-sensitive adhesive layer (B). This is preferable because it is possible to further prevent the protrusion of a part of.

  When the polycarbonate polyol and the polyester polyol are used in combination, the [polycarbonate polyol / polyester polyol] (mass ratio) is in the range of 1.5 to 7.0. Can be formed as a result, maintain a level of transparency that can be used for optical applications, and better follow the surface of the adherend (C) having a stepped portion. It is possible to prevent minute bubbles from remaining in the interface between the stepped portion and the pressure-sensitive adhesive layer (B) and the pressure-sensitive adhesive layer (B), and to adhere when wound on a roll or the like. This is preferable because part of the adhesive layer (A) and the pressure-sensitive adhesive layer (B) can be further prevented.

  Moreover, polyether polyol can also be used as said polyol (a1-1). As the polyether polyol, for example, one obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator can be used.

  Examples of the initiator include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, bisphenol A, glycerin, and triglyceride. Methylolethane, trimethylolpropane and the like can be used.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran.

  As the polyether polyol, it is preferable to use an aliphatic polyether polyol or a polyether polyol having an alicyclic structure.

  As the polyether polyol, in particular, polypropylene glycol, polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran, polytetramethylene glycol derivative obtained by reacting tetrahydrofuran and alkyl-substituted tetrahydrofuran, neopentyl glycol and tetrahydrofuran A polytetramethylene glycol derivative or the like obtained by copolymerization of can be used. Above all, as the polyether polyol, good flexibility, durability (particularly hydrolysis resistance), etc. are imparted without impairing the excellent transparency at which the adhesive sheet can be used for optical applications. In doing so, it is preferable to use polypropylene glycol, polytetramethylene glycol (PTMG), or polytetramethylene glycol derivative (PTXG).

  Moreover, as said polyol (a1-1), another polyol other than what was mentioned above can be used. As said other polyol, an acrylic polyol etc. are mentioned, for example.

  As said polyol (a1-1), it is preferable to use what has the number average molecular weight of the range of 500-5000, and what has a number average molecular weight of the range of 1000-3000 is used for shape retention. It is more preferable to obtain an adhesive sheet excellent in coating workability, initial cohesive force and the like. The number average molecular weight is a value measured under the following conditions.

[Measurement method of number average molecular weight]
The measurement of the number average molecular weight described in the present invention is a value measured under the following conditions by gel permeation chromatograph (GPC) in terms of polystyrene.

Resin sample solution; 0.4% by mass tetrahydrofuran (THF) solution Measuring device model number: HLC-8220GPC (manufactured by Tosoh Corporation)
Column: TSKgel (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran (THF)

  As the polyisocyanate (a1-2) that can be used for the production of the polyurethane (a1), alicyclic polyisocyanate, aliphatic polyisocyanate, aromatic polyisocyanate and the like can be used. It is preferable to use it.

  Examples of the alicyclic polyisocyanate include isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, 2,4- and / or 2,6-methylcyclohexane diisocyanate, cyclohexyl. Silylene diisocyanate, methylcyclohexylene diisocyanate, bis (2-isocyanatoethyl) -4-cyclohexylene-1,2-dicarboxylate and 2,5- and / or 2,6-norbornane diisocyanate, dimer acid diisocyanate, bicycloheptane Triisocyanate etc. can be used individually or in combination of 2 or more types.

  As the alicyclic polyisocyanate, among the above, an adhesive sheet having good reactivity with the polyol (a1) and excellent in heat resistance, transparency (light transmittance), and the like. In obtaining, it is preferable to use 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane.

  As a method for producing the polyurethane (a1 ′) having an isocyanate group by reacting the polyol (a1-1) and the polyisocyanate (a1-2), for example, the polyol (a1-1) charged in a reaction vessel is used. In addition, after removing moisture by heating under normal pressure or reduced pressure, the polyisocyanate (a1-2) is supplied in batch or divided and reacted.

  The reaction conditions (temperature, time, etc.) between the polyol (a1-1) and the polyisocyanate (a1-2) may be appropriately set in consideration of various conditions such as safety, quality, and cost, and are not particularly limited. For example, the reaction temperature is preferably in the range of 70 to 120 ° C., and the reaction time is preferably in the range of 30 minutes to 5 hours.

  When the polyol (a1-1) and the polyisocyanate (a1-2) are reacted, for example, a tertiary amine catalyst or an organometallic catalyst can be used as a catalyst as necessary. .

  The reaction may be performed in a solvent-free environment or in the presence of an organic solvent.

  Examples of the organic solvent include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone; and ether esters such as methyl cellosolve acetate and butyl cellosolve acetate. Solvents, aromatic hydrocarbon solvents such as toluene and xylene, amide solvents such as dimethylformamide and dimethylacetamide, and the like can be used alone or in combination of two or more. The organic solvent may be removed during the production of the polyurethane (a1 ') or after the production of the polyurethane (a1') by an appropriate method such as heating under reduced pressure or drying at normal pressure.

  As the polyurethane (a1 ′) having an isocyanate group or a hydroxyl group obtained by the above method, a polyurethane having a softening temperature of 40 ° C. or higher is preferably used, and a polyurethane having a softening temperature of 50 ° C. or higher is preferably used. More preferred. In addition, the said softening temperature refers to the value measured based on JISK2207. The upper limit of the softening temperature is preferably 100 ° C. or less.

  The polyurethane (a1) used in the present invention is a polyurethane (a1 ′) having an isocyanate group or a hydroxyl group obtained by the above method, and a (meth) acrylic monomer having a functional group capable of reacting with the hydroxyl group or the isocyanate group. It can be produced by reacting the body. Specifically, the polyurethane (a1) can be produced by mixing and reacting the polyurethane (a1 ′) obtained by the above method or an organic solvent solution thereof with the (meth) acrylic monomer. .

  As the (meth) acrylic monomer, for example, a (meth) acrylic monomer having a hydroxyl group, an amino group, a carboxyl group, a mercapto group, or the like as a functional group capable of reacting with an isocyanate group can be used. It is preferable to use a (meth) acrylic monomer having an amino group.

  Specific examples of the (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth). Acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, butanediol mono (meth) acrylate, caprolactone modified product of 2-hydroxyethyl (meth) acrylate, glycidol di (meth) acrylate Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate and the like can be used alone or in combination of two or more thereof. In the present invention, “(meth) acrylate” refers to one or both of acrylate and methacrylate.

Among these, as the (meth) acrylic monomer, for example, irradiation with active energy rays such as infrared rays, visible rays, ultraviolet rays, X-rays, electron beams, α rays, β rays, γ rays, sunlight, etc. In order to further improve the mechanical strength of the adhesive sheet that is curable and finally obtained, it is preferable to use 2-hydroxyethyl acrylate.
Moreover, an isocyanate group is mentioned as a functional group which can react with the hydroxyl group which the said polyurethane (a1) may have.
Examples of the (meth) acrylic monomer having an isocyanate group include 2- (meth) acryloyloxyethyl isocyanate, 2- (2- (meth) acryloyloxyethyloxy) ethyl isocyanate, 1,1-bis (( (Meth) acryloyloxymethyl) ethyl isocyanate and the like can be used.

  The (meth) acrylic monomer is preferably used in a range of 0.5 to 20 parts by mass with respect to 100 parts by mass of the polyurethane (a1 ′), and 0.5 to 10 parts by mass. It is more preferable to use in the range of 0.5 mass part-5 mass parts.

  More specifically, the (meth) acrylic monomer is preferably more than 50 mol% and not more than 100 mol%, more preferably 60 mol, based on the number of moles of the isocyanate group of the polyurethane (a1 ′). % To 100 mol%, more preferably 80 mol% to 100 mol% of an amount capable of supplying a functional group capable of reacting with the isocyanate group can be used. As a result, moderate flexibility, fast curability, shape retention after application to substrate, mechanical strength, durability (especially hydrolysis resistance), adhesion to substrate (especially adhesion to metal) ) And the like can be obtained.

  When the polyurethane (a1 ′) and the (meth) acrylic monomer are reacted, a urethanization catalyst can be used as necessary. The urethanization catalyst can be appropriately added at any stage of the urethanization reaction. The urethanization reaction is preferably performed until the isocyanate group content (%) becomes substantially constant.

  Examples of the urethanization catalyst include nitrogen-containing compounds such as triethylamine, triethylenediamine and N-methylmorpholine, organometallic salts such as potassium acetate, zinc stearate and stannous octylate, and organometallic compounds such as dibutyltin dilaurate. Etc. can be used.

  When a (meth) acrylic monomer having a hydroxyl group is used as the (meth) acrylic monomer, the polyol (a1-1), the polyisocyanate (a1-2), and the (meth) acrylic monomer The reaction of [Equivalent ratio of the total amount of the hydroxyl group of the polyol (a1-1) and the hydroxyl group of the (meth) acryl monomer and the isocyanate group of the polyisocyanate (a1-2) [isocyanate group] / Total amount of hydroxyl groups] = from 0.75 to 1 is preferable for controlling the molecular weight of the resulting polyurethane (a1), and more preferably from 0.79 to 0.995.

  Moreover, when using the (meth) acryl monomer which has isocyanate as the said (meth) acryl monomer, the hydroxyl group which the said polyol (a1-1) has, the said polyisocyanate (a1-2), and the said (meta) ) Controlling the molecular weight of the resulting polyurethane (a1) is carried out in the range of equivalent ratio to the total amount of isocyanate groups of the acrylic monomer [total amount of isocyanate groups / hydroxyl groups] = 0.75-1 And more preferably in the range of 0.79 to 0.995.

  As the polyurethane (a1) having a polymerizable unsaturated double bond obtained by the above method, an adhesive sheet having a storage elastic modulus within the predetermined range is formed, and as a result, it can be used for optical applications. Level of transparency can be maintained, the interface between the stepped portion and the pressure-sensitive adhesive layer (B) by having a more excellent followability to the surface having the stepped portion of the adherend (C), and Prevents minute bubbles from remaining in the pressure-sensitive adhesive layer (B), and further prevents some of the adhesive layer (A) and pressure-sensitive adhesive layer (B) from protruding when wound on a roll or the like. In order to obtain the adhesive sheet which can be used, it is preferable to use what has the weight average molecular weight of the range of 5000-100000, and it is preferable to use what has the weight average molecular weight of the range of 10000-50000.

  The adhesive composition containing the polyurethane (a1) having a polymerizable unsaturated double bond obtained by the method described above is irradiated with the active energy ray so that a polymerizable unsaturated dimer such as a (meth) acryloyl group can be obtained. The radical polymerization of the heavy bond proceeds and cures. When using what has an isocyanate group as said polyurethane (a1), the said isocyanate group may carry out the moisture hardening reaction by water (humidity) separately from the said radical polymerization.

  As the adhesive composition containing the polyurethane (a1), one containing a radical polymerization initiator can be used.

  As the radical polymerization initiator, known ones can be used, and examples thereof include a photopolymerization initiator and a peroxide, and a photopolymerization initiator is preferred for maintaining good productivity.

  As the photopolymerization initiator, conventionally known ones such as alkylphenone photopolymerization initiators such as benzophenone, camphorquinone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, titanocene photopolymerization initiators can be used. .

  Examples of commercially available photopolymerization initiators include benzophenone, 4,4-bis (diethylamino) benzophenone, 2,4,6-trimethylbenzophenone, methyl orthobenzoyl benzoate, 4-phenylbenzophenone, t-butylanthraquinone, 2 -Thioxanthones such as ethyl anthraquinone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone; diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one (for example, Ciba Darocur 1173 manufactured by Specialty Chemicals), benzyldimethyl ketal, 1-hydroxycyclohexyl-phenylketone (for example, Irgacure 184 manufactured by Ciba Specialty Chemicals), 1- [4 (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (eg, Irgacure 2959 manufactured by Ciba Specialty Chemicals), 2-methyl-2-morpholino (4-thiomethyl) Acetophenones such as phenyl) propan-1-one (for example, Irgacure 907 manufactured by Ciba Specialty Chemicals), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone; benzoin methyl ether, benzoin ethyl Benzoin ethers such as ether, benzoin isopropyl ether and benzoin isobutyl ether; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphos Acyl phosphine oxides such as zinc oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; methylbenzoyl formate (for example, BYCURE 55 manufactured by Stower), 1,7-bisacridinyl heptane, 9 -Phenylacridine, Quantacure (made by International Bio-Synthetics), Kyacure MBP (made by Nippon Kayaku Co., Ltd.), Esacure BO (made by Fratelli Lamberti), Trigonal 14 (made by Akzo), Irgacure ( Ciba Geigy Co., Ltd.), Darocur (manufactured by the company), Speed Cure (manufactured by the company), Darocur 1173 and Fi-4 mixture (manufactured by Eastman), etc. can be used alone or in combination of two or more.

  As the photopolymerization initiator, it is preferable to use Irgacure 184, Irgacure 651, or the like that can be quickly cured by irradiating active energy rays such as ultraviolet rays.

  Examples of peroxides that can be used in the radical polymerization initiator include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, cumene hydroperoxide, and peroxy. Conventionally known peroxides such as esters can be used. These may be used alone or in combination of two or more. Among these, peroxyesters and peroxydicarbonates are preferable for curing under high temperature conditions of 80 to 120 ° C., and peroxydicarbonate is particularly preferable. Examples of the peroxydicarbonate include di (4-t-butylcyclohexyl) peroxydicarbonate, and commercially available products include peroyl TCP (manufactured by NOF Corporation). Among these, as the peroxide, it is preferable to use paroyl TCP that can be quickly cured by irradiating active energy rays such as ultraviolet rays.

  The radical polymerization initiator is preferably used in a range of 0.1 parts by mass to 5 parts by mass with respect to 100 parts by mass of the polyurethane (a1), and is preferably used in a range of 1 part by mass to 3 parts by mass. More preferred.

  Moreover, as an adhesive composition containing the said polyurethane (a1), what contains a solvent as needed can be used.

  Examples of the solvent include organic solvents such as toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, hexane, acetone, cyclohexanone, 3-pentanone, acetonitrile, propionitrile, isobutyronitrile, valeronitrile, dimethyl sulfoxide, dimethylformamide, and the like. Can be used alone or in combination of two or more.

  Moreover, as said adhesive composition, what contains a well-known polyfunctional (meth) acrylate compound can be used as needed.

  The “polyfunctional” as used in the present invention refers to having two or more polymerizable unsaturated double bonds in the molecule.

  Examples of the polyfunctional (meth) acrylate compound include polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol hydroxypivalate di (meth) acrylate, and ditrimethylolpropane tetra (meth) acrylate. , Neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, etc. ) Those having 2 to 4 polymerizable unsaturated double bonds, such as (meth) acrylate esters of sugar alcohols such as acrylate and sorbitol, alone or in combination of two or more It is possible to use.

  The amount of the polyfunctional (meth) acrylate compound is preferably in the range of 5 to 30 parts by mass, more preferably 5 to 10 parts by mass with respect to 100 parts by mass of the polyurethane (a1). Range.

  As said adhesive composition, what contains an additive as needed other than the said polyurethane (a1) can be used.

  As said additive, a silane coupling agent, a phosphoric acid type additive, an acrylate type additive, a tackifier, etc. can be used. In particular, it is preferable to use a silane coupling agent rich in reactivity with glass because an adhesive sheet excellent in adhesiveness to an adherend made of glass or the like can be obtained, which reacts with the polyurethane (a1). It is more preferable to use an active energy ray-curable silane coupling agent.

  The said adhesive composition is 0.05 mass%-5 mass% in total with respect to the whole quantity of the said polyurethane (a1), the said silane coupling agent, a phosphoric acid type additive, an acrylate type additive, a tackifier, etc. It is preferable to use a material contained within the range described above because both excellent adhesion to an adherend and excellent transparency can be achieved.

  In addition to the above, the adhesive composition contains additives such as a light stabilizer, an anti-aging agent, a release modifier, a plasticizer, a softener, a filler, a colorant, and a surfactant as necessary. You can use what you want.

  Next, the pressure-sensitive adhesive layer (B) constituting the adhesive sheet of the present invention will be described.

Even if it is a case where it sticks on the surface of the to-be-adhered body (C) which has a level | step difference part as said adhesive layer (B), the interface of the said level | step-difference part and an adhesive layer (B), and the said adhesive To prevent minute bubbles from remaining in the layer (B) and to further prevent the adhesive layer (A) or the pressure-sensitive adhesive layer (B) from partially protruding when wound on a roll or the like. , storage modulus measured at a temperature 40 ° C. and a frequency 1.0 Hz (G 'is the _b40) is 1.0 × ¹⁰ 4 Pa or more and a storage modulus measured at a temperature 70 ° C. and a frequency 1 Hz (G' _b70 ) Is 1.0 × 10 ⁴ Pa or more.

The pressure-sensitive adhesive layer (B) has a storage elastic modulus (G ′ _b40 ) in the range of 1.0 × 10 ⁴ Pa to 1.0 × 10 ⁶ and a storage elastic modulus (G ′ _b70 ) of 1. Even if it is a case where using what is the range of 0.0 * 10 < ⁴ > Pa-1.0 * 10 < ⁶ > Pa sticks on the surface of the to-be-adhered body (C) which has a level | step-difference part, The interface with the pressure-sensitive adhesive layer (B) and the microbubbles are prevented from remaining in the pressure-sensitive adhesive layer (B), and the adhesive layer (A) or pressure-sensitive adhesive layer when wound on a roll or the like (B) It is preferable when obtaining the adhesive sheet | seat which can prevent a part of protrusion further.

The storage elastic modulus (G ′ _b40 ) at 40 ° C. and the storage elastic modulus (G ′ _b70 ) at 70 ° C. were _{measured using} a viscoelasticity tester (manufactured by Rheometrics, trade name: Ares 2KSTD). It can be obtained by sandwiching a test piece between parallel disks, which are measuring parts of the machine, and measuring the storage elastic modulus and loss elastic modulus at a temperature of 40 ° C. or 70 ° C. and a frequency of 1 Hz. In addition, as a test piece used by the said measurement, what cut | judged the said adhesive layer (B) in the circular shape which consists of a 1 mm thickness and a diameter of 8 mm is used.

  As an adhesive composition which forms the said adhesive layer (B), what contains adhesive resins, such as an acrylic polymer and a urethane type resin, can be used. Among them, as the pressure-sensitive adhesive composition, it is possible to maintain excellent adhesion to the adherend (C) having a stepped portion by using an acrylic pressure-sensitive adhesive containing an acrylic polymer, and It is preferable for maintaining good transparency of the pressure-sensitive adhesive layer (B).

  As the acrylic polymer, a polymer obtained by polymerizing a (meth) acrylic monomer can be used. Examples of the (meth) acrylic monomer include (meth) acrylate, and the use of the one containing a (meth) acrylate having an alkyl group having 2 to 14 carbon atoms has an adhesive force and an adhesive force. It is preferable in securing.

  Examples of the (meth) acrylate having an alkyl group having 2 to 14 carbon atoms include ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, t-butyl acrylate, and n-hexyl. Acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, isodecyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec -Butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate Rate, n- octyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, isononyl methacrylate, isodecyl methacrylate, can be used lauryl methacrylate and the like.

  Especially, as said (meth) acrylate, it is preferable to use the alkyl (meth) acrylate which has a C4-C9 alkyl group, and the alkyl acrylate which has a C4-C9 alkyl group is used. It is more preferable.

  As the alkyl acrylate having an alkyl group having 4 to 9 carbon atoms, it is preferable to use n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, and ethyl acrylate. Is more preferable in securing the above.

  The (meth) acrylate having an alkyl group having 2 to 14 carbon atoms is preferably used in a range of 90% by mass to 99% by mass with respect to the total amount of the (meth) acrylic monomer, and is 90% by mass. It is more preferable to use in the range of -96 mass% in order to set the storage elastic modulus in the preferred range and to secure a suitable adhesive force and adhesive strength.

  As said acrylic polymer, what has polar groups, such as a hydroxyl group, a carboxyl group, an amide group, can be used, for example.

  The acrylic polymer can be produced by polymerizing a (meth) acrylic monomer containing a (meth) acrylic monomer having a polar group such as a hydroxyl group, a carboxyl group, or an amide group.

  Examples of the (meth) acrylic monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, hydroxypropyl (meth) acrylate, Caprolactone-modified (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate and the like can be used. Especially, it is preferable to use 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate as the (meth) acrylic monomer having a hydroxyl group.

  Examples of the (meth) acrylic monomer having a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, acrylic acid or methacrylic acid dimer, ethylene oxide-modified succinic acid acrylate, and the like. Can be used. Among them, it is preferable to use acrylic acid as the (meth) acrylic monomer having a carboxyl group.

  Examples of the (meth) acrylic monomer having an amide group include N-vinyl-2-pyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, N, N-dimethylacrylamide, and 2- (perhydrophthalimide-N. -Yl) ethyl acrylate and the like can be used. Of these, N-vinyl-2-pyrrolidone, N-vinylcaprolactam, and acryloylmorpholine are preferably used as the (meth) acrylic monomer having an amide group.

  Examples of the other vinyl monomers having a polar group include vinyl acetate, acrylonitrile, maleic anhydride, itaconic anhydride and the like.

  The (meth) acrylic monomer having a polar group should be used in the range of 0.1% by mass to 20% by mass with respect to the total amount of the (meth) acrylic monomer used for the production of the acrylic polymer. It is preferable to use in the range of 1% by mass to 13% by mass, and it is preferable to use in the range of 1.5% by mass to 8% by mass in terms of cohesion, holding power, adhesion amount, and adhesive strength. It is further preferable when adjusting to a range.

The acrylic polymer preferably has a weight average molecular weight of 400,000 to 1,400,000, preferably 600,000 to 1,200,000 in order to adjust the adhesive strength to a suitable range, and has a temperature of 40 ° C. The storage elastic modulus (G ′ _b40 ) measured at a frequency of 1.0 Hz is in the range of 1.0 × 10 ⁴ Pa to 1.0 × 10 ⁶ and the storage elastic modulus (G ′ _b70 ) is 1.0. It is preferable when adjusting to the range of * 10 < ⁴ > Pa-1.0 * 10 < ⁶ > Pa.

  The measurement of the said weight average molecular weight is the value measured on condition of the following by the gel permeation chromatograph (GPC) by polystyrene conversion.

Sample: 0.4 mass% tetrahydrofuran (THF) solution of acrylic polymer Measuring device model number: HLC-8220GPC (manufactured by Tosoh Corporation)
Column: TSKgel (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran (THF)

  As the pressure-sensitive adhesive composition, in order to further increase the cohesive force, in addition to the acrylic polymer, it is possible to use a pressure-sensitive adhesive having a storage elastic modulus in the predetermined range in addition to the acrylic polymer. Preferred for forming the layer.

  Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, chelate crosslinking agents, and the like.

  The crosslinking agent is preferably used in the range where the gel fraction of the pressure-sensitive adhesive layer (B) to be formed is 25% by mass to 80% by mass, and the gel fraction is in the range of 40% by mass to 75% by mass. It is more preferable to use in the range of 50% by mass to 75% by mass in order to increase the adhesiveness and to keep the storage elastic modulus within a predetermined range. The gel fraction in the present invention is expressed as a percentage of the original mass by immersing the cured pressure-sensitive adhesive layer in toluene, measuring the mass after drying of the insoluble matter remaining after standing for 24 hours, and the original mass. Is.

  As the pressure-sensitive adhesive composition, one containing a tackifying resin can be used to further increase the adhesive strength.

  The tackifying resin is preferably used in the range of 10 parts by mass to 60 parts by mass, and preferably in the range of 20 parts by mass to 50 parts by mass with respect to 100 parts by mass of the acrylic polymer. It is more preferable when giving a sufficient adhesive force.

  As said adhesive composition, what contains a well-known and usual additive other than the above can be used.

  As said additive, in order to improve the adhesiveness to a glass base material, for example, a silane coupling agent is used in the range of 0.001 to 0.005 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive composition. It is preferable to use it. Moreover, as said additive, a plasticizer, a softener, a filler, a pigment, a flame retardant etc. can also be used as needed.

  In the adhesive sheet of the present invention, for example, the adhesive composition (A) is formed by applying the adhesive composition on one surface of a release liner and drying it as necessary [1], etc. A step [2] of forming the pressure-sensitive adhesive layer (B) by applying the pressure-sensitive adhesive composition to one side of the release liner and drying, if necessary, and the adhesive layer (A); It can manufacture by passing through the process [3] etc. which laminate | stack the said adhesive layer (B).

  Examples of a method for applying the adhesive composition or the pressure-sensitive adhesive composition to the surface of the release liner include a method using a comma coater or a lip coater. The drying can be performed using, for example, a dryer set to a temperature of about 60 ° C. to 90 ° C.

  As the adhesive sheet of the present invention obtained by the above method, it is preferable to use a sheet having a thickness of 10 μm to 300 μm, more preferably a sheet having a thickness of 25 μm to 200 μm, and 25 μm to 150 μm. It is more preferable to use the one having a thickness of 5 mm. The adhesive sheet having the thickness in the above range can maintain a level of transparency that can be used for optical applications, and has even better followability to the surface of the adherend (C) having a stepped portion. By providing, the interface between the stepped portion and the pressure-sensitive adhesive layer (B) and the microbubbles are prevented from remaining in the pressure-sensitive adhesive layer (B), and the adhesive layer when wound on a roll or the like It is preferable for further preventing the protrusion of part of (A) and the pressure-sensitive adhesive layer (B).

  In addition, the adhesive sheet of the present invention can exhibit the above-described excellent effects even if it is thin as described above, and can maintain the surface hardness derived from the adherend. It can be suitably used when manufacturing the required image display device or the like.

  Moreover, as said adhesive sheet, it is preferable to use what the thickness of the said adhesive bond layer (A) which comprises it is the range of 5 micrometers-150 micrometers, and the thing which is the range of 10 micrometers-100 micrometers is used. More preferably, use of a material having a range of 10 μm to 75 μm can maintain a level of transparency that can be used for optical applications, and the surface of the adherend (C) having a stepped portion. By providing even more excellent followability, it is possible to prevent minute bubbles from remaining in the interface between the stepped portion and the pressure-sensitive adhesive layer (B) and in the pressure-sensitive adhesive layer (B), and to be wound around a roll or the like. It is further preferable to further prevent the adhesive layer (A) and the pressure-sensitive adhesive layer (B) from partially protruding when removed.

  Moreover, it is preferable to use what the thickness of the said adhesive layer (B) which comprises it as the said adhesive sheet is the range of 5 micrometers-150 micrometers, and uses the thing which is the range of 10 micrometers-100 micrometers. It is more preferable to use a material having a range of 10 μm to 75 μm, and the stepped portion can be further improved in conformity to the surface having the stepped portion of the adherend (C). The interface with the pressure-sensitive adhesive layer (B) and the microbubbles are prevented from remaining in the pressure-sensitive adhesive layer (B), and the adhesive layer (A) or pressure-sensitive adhesive layer when wound on a roll or the like In order to further prevent some of the protrusion of (B), it is further preferable.

  The adhesive sheet has a ratio [the thickness of the adhesive layer (A) / the thickness of the adhesive layer (B)] of the thickness of the adhesive layer (A) and the adhesive layer (B) of 8 / It is preferable to use the one in the range of 2 to 2/8, and use at a thickness of 5.5 / 4.5 to 4.5 / 5.5 is preferable to the step portion of the adhesive sheet. This is particularly preferable because distortion such as wrinkles that can be caused by insufficient followability, appearance defects of the image display apparatus caused by the distortion, distortion of images displayed on the image display apparatus, and the like can be more effectively prevented.

  As the adhesive sheet of the present invention, a sheet having a light transmittance of 85% or more and a haze of 2.0 or less is used when used for manufacturing the image display device or the like. In order to maintain the transparency of the image display unit, it is preferable to use a light transmittance of 90% or more and a haze of 1.5 or less.

  The adhesive sheet of the present invention has a wavelength of 380 nm to 780 nm after being left in an environment of a temperature of 60 ° C. and a relative humidity of 90% RH for 500 hours when used for manufacturing the image display device or the like. It is preferable to use one having a light transmittance of 85% or more and a haze of 2.0 or less, and having a light transmittance of 90% or more and a haze of 1.5 or less at a wavelength of 380 nm to 780 nm. It is preferable to use it for maintaining good transparency of an image display unit such as a display.

  Next, the adherend (C) to which the adhesive sheet of the present invention can be attached will be described.

  The pressure-sensitive adhesive sheet of the present invention can be affixed to the surface of various adherends, and in particular, can be suitably affixed and used for an adherend (C) having a stepped portion on the surface thereof.

  As said adherend (C), the adherend which has a level | step-difference part resulting from a decoration layer etc. in part of surfaces, such as a transparent member, is mentioned, for example.

As the transparent member constituting the adherend (C), for example, a substrate obtained using glass, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, cellophane, diacetylcellulose, triacetylcellulose, Acetylcellulose butyrate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polystyrene, polycarbonate, polymethylpentene, polysulfone, polyetheretherketone, polyethersulfone, polyetherimide, polyimide, fluorine A member obtained by using resin, nylon, acrylic resin, silicon dioxide or the like can be used. Especially, it is preferable to use a glass substrate as the transparent member in order to achieve both high transparency and surface hardness.
Is preferable.

  As the adherend (C), for the purpose of further improving the adhesion to the pressure-sensitive adhesive layer (B), surface unevenness treatment by a sandblasting method or a solvent treatment method, or a corona discharge treatment method. Further, those subjected to surface oxidation treatment by chromic acid treatment method, flame treatment method, hot air treatment method, ozone treatment method, ultraviolet irradiation treatment method and the like can be used.

  Examples of the adherend (C) in which a decorative layer is provided on a part of the transparent member include an image display panel provided with a decorative layer for the purpose of imparting design properties, light shielding properties, and the like. It is done.

  As the transparent member, a member having a thickness of 38 μm to 1000 μm is preferably used, a member having a thickness of 50 μm to 700 μm is more preferably used, and a member having a thickness of 100 μm to 500 μm is used. Further, it is more preferable in reducing the thickness of articles including image display devices.

  As the transparent member, it is preferable to use a so-called hard coat film having a hard coat layer on one side or both sides for the purpose of preventing appearance defects such as scratches and dents on the surface.

  As the hard coat film, those having a pencil hardness of H or higher, preferably 2H or higher, on the surface of the hard coat layer constituting the hard coat film can be used. In addition, the pencil hardness of the said hard-coat layer points out the value which measured the surface of the said hard-coat film based on JISK5600-5-4 (1999).

  Moreover, a transparent conductive film is mentioned as said transparent member. As a transparent conductive film, what has a conductive layer in the surface layer of at least one side of a film or a sheet | seat can be used, The thing by which the electrically conductive substance was provided in the surface layer of the said film or sheet | seat by vapor deposition or coating is mentioned. Among these, as the transparent conductive film, it is preferable to use a transparent conductive film having a conductive layer in which a conductive material is formed by vapor deposition.

  As the conductive material, for example, indium tin oxide, indium oxide, tin oxide, zinc oxide, cadmium oxide, gallium oxide, titanium oxide and the like can be used, and indium tin oxide having excellent transparency and conductivity is used. Is preferred.

  Examples of the decorative layer provided on a part of the transparent member include a layer provided by printing by a general printing method. Examples of the printing method include a silk printing method, a screen printing method, a thermal transfer printing method, and a gravure printing method.

  The decorative layer is not particularly limited as long as it imparts various design properties to the transparent substrate. For example, characters and figures that are visually recognized around the image display unit when used as an image display panel, or And a black border-like decorative layer provided in a frame shape on the image display unit.

  The thickness of the decorative layer is preferably in the range of 2 μm to 50 μm, more preferably in the range of 2 μm to 30 μm, and in the range of 2 μm to 20 μm, color loss or printing of the decorative layer Defects can be suppressed, suitable design properties can be easily imparted, and the thickness of articles such as the image display device can be reduced.

  An image display panel such as a hard coat film which is a base material in which a decorative layer is provided on a part of the transparent member, or a touch panel member on which a transparent conductive film is formed is provided on the surface of various image display modules. It can be affixed using an adhesive sheet.

  As the image display module, a liquid crystal display module, an organic EL module, or the like can be used.

  The adherend (C) in which a decorative layer is provided on a part of the transparent member can be fixed to an arbitrary member using the adhesive sheet. In addition, the said adherend (C) and the said adhesive sheet are not the adhesive layer (A) which comprises the said adhesive sheet in the level | step-difference part which comprises an adherend (C), but the said adhesion. The step portion and the pressure-sensitive adhesive layer (B) can be adhered so that the agent layer (B) is in contact with the surface of the adherend (C) having a step portion, which is more excellent. ) And the adhesive layer (A) or the adhesive layer (B) when the microbubbles are prevented from remaining in the adhesive layer (B) and wound on a roll or the like. This is preferable because it is possible to further prevent the protrusion of a part of.

  Examples of the adhesion method include a method of laminating the adherend (C) and other members via the adhesive sheet and irradiating active energy rays. At that time, when a part of the adherend (C) is transparent, active energy rays can be irradiated from the surface of the adherend (C) or the like.

  The active energy ray is used to form an adhesive layer (A ′) by curing the adhesive layer (A) constituting the adhesive sheet.

  It is preferable to use ultraviolet rays as the active energy rays. The ultraviolet rays may be irradiated in an inert gas atmosphere such as nitrogen gas or an air atmosphere in order to efficiently perform the curing reaction by the ultraviolet rays. In addition, if necessary, heat may be used as an energy source, and the active energy ray may be irradiated and then heated.

  When ultraviolet rays are used as the active energy ray, low pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, metal halide lamp, electrodeless lamp (fusion lamp), chemical lamp, black light lamp, mercury-xenon lamp, short arc lamp , Helium / cadmium laser, argon laser, sunlight, LED and the like. In addition, a xenon-flash lamp capable of flashing active energy rays is preferable because the influence of heat on the substrate can be minimized.

  As the active energy ray irradiation apparatus, in addition to those described above, a germicidal lamp, a carbon arc, a xenon lamp, a metal halide lamp, a scanning type, a curtain type electron beam accelerator, and the like can be used.

  The pressure-sensitive adhesive sheet of the present invention can be suitably used exclusively for producing articles such as image display devices.

The article, for example, the pressure-sensitive adhesive layer (B) constituting the adhesive sheet is pressure-bonded to the surface of an adherend (C) having a stepped portion, and then the adhesive layer (A) is A storage elastic modulus (G) measured at a temperature of 40 ° C. and a frequency of 1.0 Hz is obtained by pressure-bonding to the surface of another adherend and then irradiating the adhesive layer (A) with active energy rays. 'in _A'40) is 1.0 × ¹⁰ 4 Pa or more and a storage modulus measured at a temperature 70 ° C. and a frequency _1Hz (G'a'70) is 1.0 × ¹⁰ 4 Pa or more in which the adhesive It can be produced by forming the layer (A ′).

  The image display device, for example, pressure-bonds the pressure-sensitive adhesive layer (B) constituting the adhesive sheet to the surface of the adherend (C) having a stepped portion, and then the adhesive layer ( A) is affixed to the surface of the image display module, autoclaved, and then produced by forming an adhesive layer (A ′) by irradiating active energy rays and curing the adhesive layer (A). be able to.

  The surface hardness of the image display device measured according to JIS K 5600-5-4 (1999) is preferably F to 9H. When the surface hardness is in the above range, appearance defects such as scratches and dents on the image display device can be easily prevented.

<Adhesive composition a>
Polycarbonate polyol obtained by reacting 46.4 parts by mass of polypropylene glycol (number average molecular weight; 2,000), 1,4-dimethanolcyclohexane, 1,6-hexanediol and dimethyl carbonate in a reaction vessel. Number average molecular weight 900) is 38.1 parts by mass, 2-hydroxyethyl acrylate 0.8 parts by mass, 2,6-di-tert-butyl-cresol 0.3 parts by mass, p-methoxyphenol 0.05 part by mass Was added.

  After adjusting the temperature in the reaction vessel to 40 ° C., 14.7 parts by mass of isophorone diisocyanate was added to the reaction vessel.

  Next, 0.1 part by mass of dioctyltin dineodecanate was added to the reaction vessel, and the temperature was raised to 80 ° C. over 1 hour, then held at 80 ° C. for 12 hours, and all isocyanate groups disappeared. After confirming that the product was cooled, polyurethane (A-1) having a polymerizable unsaturated double bond having a weight average molecular weight of 40000 was obtained.

  Next, in a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer and adjusted to 80 ° C., 100 parts by mass of polyurethane (A-1) having the polymerizable unsaturated double bond, and 67 parts by mass of ethyl acetate And mixed. Next, Irgacure 184 (manufactured by Ciba Specialty Co., Ltd.) 0.3 parts by mass was supplied to the mixture and stirred to obtain an adhesive composition a.

<Adhesive composition b>
In a reaction vessel, 80 parts by mass of an aliphatic polycarbonate polyol having a number average molecular weight of 2000 obtained by reacting 1,5-pentanediol, 1,6-hexanediol and dialkyl carbonate, 1,4-butanediol and adipic acid The mixture was mixed with 26 parts by mass of a polyester polyol having a number average molecular weight of 2000 obtained by reacting and heating to 100 ° C. under reduced pressure conditions to dehydrate until the water content became 0.05% by mass.

  Next, after the mixture of the aliphatic polycarbonate polyol and the polyester polyol cooled to 70 ° C. and 26 parts by mass of dicyclohexylmethane-4,4′-diisocyanate were heated to 100 ° C. By reacting for 3 hours until the content becomes constant, a urethane prepolymer having an isocyanate group was obtained.

  A mixture of 100 parts by mass of the urethane prepolymer heated and melted at 100 ° C., 11.4 parts by mass of 2-hydroxyethyl acrylate, and 0.01 parts by mass of stannous octylate are mixed. By making it react until it becomes constant, the polyurethane (A-2) which has a polymerizable unsaturated double bond with a weight average molecular weight of 15000 was obtained. In addition, the said 2-hydroxyethyl acrylate used the quantity in which the total number of the isocyanate group which the said urethane prepolymer has all reacts with the hydroxyl group of the said 2-hydroxyethyl acrylate theoretically. The amount of isocyanate groups (NCO%) of the polyurethane (A-2) having a polymerizable unsaturated double bond was 0% by mass.

  Next, 100 parts by mass of the polyurethane (A-2) having a polymerizable unsaturated double bond and 2 parts by mass of Irgacure 184 (manufactured by Ciba Specialty Co., Ltd.) are mixed and stirred, and ethyl acetate is supplied to reduce the nonvolatile content. The adhesive composition b was obtained by adjusting to 57 mass%.

<Adhesive composition c>
In a reaction vessel, 80 parts by mass of an aliphatic polycarbonate polyol having a number average molecular weight of 2000 obtained by reacting 1,5-pentanediol, 1,6-hexanediol and dialkyl carbonate, 1,6-hexanediol and adipic acid Was mixed with 26 parts by mass of a polyester polyol having a number average molecular weight of 4500 obtained by reacting with the above, and dehydrated by heating to 100 ° C. under reduced pressure conditions until the water content became 0.05% by mass.

  Next, after the mixture of the aliphatic polycarbonate polyol and the polyester polyol cooled to 70 ° C. and 26 parts by mass of dicyclohexylmethane-4,4′-diisocyanate were heated to 100 ° C. By reacting for 3 hours until the content becomes constant, a urethane prepolymer having an isocyanate group was obtained.

  A mixture of 100 parts by mass of the urethane prepolymer heated and melted at 100 ° C., 11.4 parts by mass of 2-hydroxyethyl acrylate, and 0.01 parts by mass of stannous octylate are mixed. By making it react until it becomes constant, the polyurethane (A-3) which has a polymerizable unsaturated double bond with a weight average molecular weight of 17000 was obtained. In addition, the said 2-hydroxyethyl acrylate used the quantity in which the total number of the isocyanate group which the said urethane prepolymer has all reacts with the hydroxyl group of the said 2-hydroxyethyl acrylate theoretically. The amount of isocyanate groups (NCO%) of the polyurethane (A-3) having a polymerizable unsaturated double bond was 0% by mass.

  Next, 100 parts by mass of the polyurethane (A-3) having a polymerizable unsaturated double bond and 2 parts by mass of Irgacure 184 (manufactured by Ciba Specialty Co., Ltd.) are mixed and stirred, and ethyl acetate is supplied to reduce the nonvolatile content. The adhesive composition c was obtained by adjusting to 57 mass%.

<Adhesive composition d>
In a reaction vessel, 80 parts by mass of an aliphatic polycarbonate polyol having a number average molecular weight of 2000 obtained by reacting 1,5-pentanediol, 1,6-hexanediol and dialkyl carbonate, 1,6-hexanediol and sebacic acid Was mixed with 26 parts by mass of a polyester polyol having a number average molecular weight of 3500 obtained by reacting and heating to 100 ° C. under reduced pressure conditions to dehydrate until the water content became 0.05% by mass.

  Next, after the mixture of the aliphatic polycarbonate polyol and the polyester polyol cooled to 70 ° C. and 26 parts by mass of dicyclohexylmethane-4,4′-diisocyanate were heated to 100 ° C. By reacting for 3 hours until the content becomes constant, a urethane prepolymer having an isocyanate group was obtained.

  A mixture of 100 parts by mass of the urethane prepolymer heated and melted at 100 ° C., 11.4 parts by mass of 2-hydroxyethyl acrylate, and 0.01 parts by mass of stannous octylate are mixed. By making it react until it becomes constant, the polyurethane (A-4) which has a polymerizable unsaturated double bond of the weight average molecular weight 20000 was obtained. In addition, the said 2-hydroxyethyl acrylate used the quantity in which the total number of the isocyanate group which the said urethane prepolymer has all reacts with the hydroxyl group of the said 2-hydroxyethyl acrylate theoretically. The amount of isocyanate groups (NCO%) of the polyurethane (A-4) having a polymerizable unsaturated double bond was 0% by mass.

  Next, 100 parts by mass of the polyurethane (A-4) having a polymerizable unsaturated double bond and 2 parts by mass of Irgacure 184 (manufactured by Ciba Specialty Co., Ltd.) are mixed and stirred, and ethyl acetate is supplied to reduce the nonvolatile content. By adjusting to 57% by mass, an adhesive composition d was obtained.

<Adhesive composition e>
In a reaction vessel, 80 parts by weight of an aliphatic polycarbonate polyol having a number average molecular weight of 2000 obtained by reacting 1,5-pentanediol, 1,6-hexanediol and dialkyl carbonate, 1,2-ethanediol and adipic acid The mixture was mixed with 26 parts by mass of a polyester polyol having a number average molecular weight of 2000 obtained by reacting and heating to 100 ° C. under reduced pressure conditions to dehydrate until the water content became 0.05% by mass.

  Next, after the mixture of the aliphatic polycarbonate polyol and the polyester polyol cooled to 70 ° C. and 26 parts by mass of dicyclohexylmethane-4,4′-diisocyanate were heated to 100 ° C. By reacting for 3 hours until the content becomes constant, a urethane prepolymer having an isocyanate group was obtained.

  A mixture of 100 parts by mass of the urethane prepolymer heated and melted at 100 ° C., 11.4 parts by mass of 2-hydroxyethyl acrylate, and 0.01 parts by mass of stannous octylate are mixed. By making it react until it becomes constant, the polyurethane (A-5) which has a polymerizable unsaturated double bond with a weight average molecular weight of 17000 was obtained. In addition, the said 2-hydroxyethyl acrylate used the quantity in which the total number of the isocyanate group which the said urethane prepolymer has all reacts with the hydroxyl group of the said 2-hydroxyethyl acrylate theoretically. The amount of isocyanate group (NCO%) of the polyurethane (A-5) having a polymerizable unsaturated double bond was 0% by mass.

  Next, 100 parts by mass of the polyurethane (A-5) having a polymerizable unsaturated double bond and 2 parts by mass of Irgacure 184 (manufactured by Ciba Specialty Co., Ltd.) are mixed and stirred, and ethyl acetate is supplied to reduce the nonvolatile content. The adhesive composition e was obtained by adjusting to 57 mass%.

<Adhesive composition f>
In a reaction vessel, 93 parts by mass of an aliphatic polycarbonate polyol having a number average molecular weight of 2000 obtained by reacting 1,5-pentanediol, 1,6-hexanediol and dialkyl carbonate, 1,6-hexanediol and adipic acid The mixture was mixed with 13 parts by mass of a polyester polyol having a number average molecular weight of 4500 obtained by reacting, and heated to 100 ° C. under reduced pressure conditions to dehydrate until the water content became 0.05% by mass.

  Next, after the mixture of the aliphatic polycarbonate polyol and the polyester polyol cooled to 70 ° C. and 26 parts by mass of dicyclohexylmethane-4,4′-diisocyanate were heated to 100 ° C. By reacting for 3 hours until the content becomes constant, a urethane prepolymer having an isocyanate group was obtained.

  A mixture of 100 parts by mass of the urethane prepolymer heated and melted at 100 ° C., 11.4 parts by mass of 2-hydroxyethyl acrylate, and 0.01 parts by mass of stannous octylate are mixed. By making it react until it becomes constant, the polyurethane (A-6) which has a polymerizable unsaturated double bond with a weight average molecular weight of 16000 was obtained. In addition, the said 2-hydroxyethyl acrylate used the quantity in which the total number of the isocyanate group which the said urethane prepolymer has all reacts with the hydroxyl group of the said 2-hydroxyethyl acrylate theoretically. The isocyanate group content (NCO%) of the polyurethane (A-6) having a polymerizable unsaturated double bond was 0% by mass.

  Next, 100 parts by mass of the polyurethane (A-6) having a polymerizable unsaturated double bond and 2 parts by mass of Irgacure 184 (manufactured by Ciba Specialty Co., Ltd.) are mixed and stirred, and ethyl acetate is supplied to reduce the nonvolatile content. The adhesive composition f was obtained by adjusting to 57 mass%.

<Adhesive composition g>
In a reaction vessel, 93 parts by mass of an aliphatic polycarbonate polyol having a number average molecular weight of 2000 obtained by reacting 1,5-pentanediol, 1,6-hexanediol and dialkyl carbonate, 1,6-hexanediol and sebacic acid The mixture was mixed with 13 parts by mass of a polyester polyol having a number average molecular weight of 3500 obtained by reacting, and heated to 100 ° C. under reduced pressure conditions to dehydrate until the water content became 0.05% by mass.

  Next, after the mixture of the aliphatic polycarbonate polyol and the polyester polyol cooled to 70 ° C. and 26 parts by mass of dicyclohexylmethane-4,4′-diisocyanate were heated to 100 ° C. By reacting for 3 hours until the content becomes constant, a urethane prepolymer having an isocyanate group was obtained.

  A mixture of 100 parts by mass of the urethane prepolymer heated and melted at 100 ° C., 11.4 parts by mass of 2-hydroxyethyl acrylate, and 0.01 parts by mass of stannous octylate are mixed. By making it react until it becomes constant, the polyurethane (A-7) which has a polymerizable unsaturated double bond with a weight average molecular weight of 16000 was obtained. In addition, the said 2-hydroxyethyl acrylate used the quantity in which the total number of the isocyanate group which the said urethane prepolymer has all reacts with the hydroxyl group of the said 2-hydroxyethyl acrylate theoretically. The isocyanate group content (NCO%) of the polyurethane (A-7) having a polymerizable unsaturated double bond was 0% by mass.

  Next, 100 parts by mass of the polyurethane having a polymerizable unsaturated double bond (A-7) and 2 parts by mass of Irgacure 184 (manufactured by Ciba Specialty Co., Ltd.) are mixed and stirred, and ethyl acetate is supplied to reduce the nonvolatile content. The adhesive composition g was obtained by adjusting to 57 mass%.

<Adhesive composition h>
Preparation of acrylic copolymer In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, 85 parts by mass of n-butyl acrylate, 15 parts by mass of methyl methacrylate, 4 parts by mass of acrylic acid, dimethyl 1 part by mass of aminoethyl acrylate was dissolved in ethyl acetate and polymerized to obtain an acrylic copolymer (1) having a mass average molecular weight (Mw) of 700,000.
0.33 parts by mass of an isocyanate-based crosslinking agent (Coronate L-45 solid content 45% by mass, manufactured by Nippon Polyurethane Industry Co., Ltd.) and an epoxy-based crosslinking agent (E, manufactured by Soken Chemical Co., Ltd.) with respect to 100 parts by mass of the acrylic copolymer. -2XM solid content 2% by mass) was added, and stirred with a stirrer for 20 minutes to obtain an adhesive composition (h).

<Adhesive composition i>
Preparation of acrylic copolymer In a reaction vessel equipped with a stirrer, cold flow cooler, thermometer, dropping funnel and nitrogen gas inlet, 75 parts by mass of methoxyethyl acrylate, 24 parts by mass of n-butyl acrylate, 1 part by mass of hydroxyethyl acrylate And 0.22 parts by mass of 2,2′-azobisisobutylnitrile as a polymerization initiator in 100 parts by mass of ethyl acetate, and after substitution with nitrogen, polymerization was carried out at 80 ° C. for 8 hours to obtain an acrylic copolymer having a weight average molecular weight of 700,000. A polymer (2) was obtained.
0.12 parts by mass of an isocyanate-based cross-linking agent (TD-75 solid content 75% by mass, manufactured by Soken Chemical Co., Ltd.) is added to 100 parts by mass of the acrylic copolymer (2), and the mixture is stirred with a stirrer for 20 minutes. An agent composition (i) was obtained.

<Comparative adhesive composition j>
In a 500 mL reaction vessel equipped with a stirrer, 138 g of polyester polyol having a number average molecular weight of 2,000 (P-2010 manufactured by Kuraray Co., Ltd., esterified product of adipic acid and 3-methyl-1,5-pentanediol), 16.2 g of 2-hydroxyethyl acrylate, 185 g of isobornyl acrylate as a diluent, 185 mg of dibutyltin dilaurate as a catalyst, and 92.7 mg of 2,6-di-tert-butyl-4-methylphenol as a polymerization inhibitor The mixture was heated to 70 ° C. with stirring under a nitrogen atmosphere containing 5% by volume of oxygen.

  31.1 g of isophorone diisocyanate was gradually added to the mixture and allowed to react for 9 hours. After confirming that all the isocyanate groups of the isophorone diisocyanate were consumed, urethane acrylate was obtained.

  100 parts by mass of the urethane acrylate and 1 part by mass of Irgacure 819 were mixed and stirred to obtain a comparative adhesive composition j.

Example 1
100 parts by weight of the adhesive composition a was applied on a 75 μm thick polyester film (hereinafter “# 75 peeled film”) having one surface peeled with a silicone compound so that the thickness after drying was 25 μm. By drying at 85 ° C. for 4 minutes, an adhesive sheet was produced on the surface of the # 75 release film.

  Next, 100 parts by mass of the pressure-sensitive adhesive composition h was applied on a 38 μm-thick polyester film (hereinafter “# 38 release film”) having one surface peel-treated with a silicone compound so that the thickness after drying was 25 μm. And then dried at 85 ° C. for 4 minutes to prepare an adhesive sheet on the surface of the # 38 release film. An adhesive sheet was prepared by bonding the adhesive sheet to the pressure-sensitive adhesive sheet.

(Example 2)
The adhesive composition a100 parts by weight is applied onto a # 75 release film so that the thickness after drying is 40 μm, and dried at 85 ° C. for 4 minutes to adhere to the surface of the # 75 release film. A sheet was produced.

  Next, 100 parts by weight of the pressure-sensitive adhesive composition h was applied on a # 38 release film so that the thickness after drying was 10 μm, and dried at 85 ° C. for 4 minutes, whereby the # 38 release film An adhesive sheet was produced on the surface. An adhesive sheet was prepared by bonding the adhesive sheet to the pressure-sensitive adhesive sheet.

(Example 3)
100 parts by weight of the adhesive composition a was applied on a # 75 release film so that the thickness after drying was 10 μm, and dried at 85 ° C. for 4 minutes to adhere to the surface of the # 75 release film A sheet was produced.

  Next, 100 parts by weight of the pressure-sensitive adhesive composition h was applied on a # 38 release film so that the thickness after drying was 40 μm, and dried at 85 ° C. for 4 minutes, whereby the # 38 release film An adhesive sheet was produced on the surface. An adhesive sheet was prepared by bonding the adhesive sheet to the pressure-sensitive adhesive sheet.

Example 4
100 parts by mass of the adhesive composition a was applied on a # 75 release film so that the thickness after drying was 25 μm, and dried at 85 ° C. for 4 minutes to adhere to the surface of the # 75 release film A sheet was produced.

  Next, 100 parts by weight of the pressure-sensitive adhesive composition i was applied onto a # 38 release film so that the thickness after drying was 25 μm, and dried at 85 ° C. for 4 minutes, whereby the # 38 release film An adhesive sheet was produced on the surface. An adhesive sheet was prepared by bonding the adhesive sheet to the pressure-sensitive adhesive sheet.

(Example 5)
An adhesive sheet was produced in the same manner as in Example 1 except that 100 parts by mass of the adhesive composition b was used instead of 100 parts by mass of the adhesive composition a.

(Example 6)
An adhesive sheet was produced in the same manner as in Example 1 except that 100 parts by mass of the adhesive composition c was used instead of 100 parts by mass of the adhesive composition a.

(Example 7)
An adhesive sheet was produced in the same manner as in Example 1 except that 100 parts by mass of the adhesive composition d was used instead of 100 parts by mass of the adhesive composition a.

(Example 8)
An adhesive sheet was produced in the same manner as in Example 1 except that 100 parts by mass of the adhesive composition e was used instead of 100 parts by mass of the adhesive composition a.

Example 9
An adhesive sheet was produced in the same manner as in Example 1 except that 100 parts by mass of the adhesive composition f was used instead of 100 parts by mass of the adhesive composition a.

(Example 10)
An adhesive sheet was prepared in the same manner as in Example 1 except that 100 parts by mass of the adhesive composition g was used instead of 100 parts by mass of the adhesive composition a.

(Comparative Example 1)
100 parts by weight of the adhesive composition a was applied on a # 75 release film so that the thickness after drying was 50 μm, and dried at 85 ° C. for 4 minutes to adhere to the surface of the # 75 release film A sheet was produced.

  Next, an adhesive sheet was prepared by laminating a # 38 release film on one side of the adhesive sheet.

(Comparative Example 2)
The above pressure-sensitive adhesive composition h100 parts by mass is coated on a # 75 release film so that the thickness after drying is 50 μm, and dried at 85 ° C. for 4 minutes, thereby sticking to the surface of the # 75 release film. A sheet was produced.

  Next, a pressure-sensitive adhesive sheet was prepared by laminating a # 38 release film on one side of the pressure-sensitive adhesive sheet.

(Comparative Example 3)
An adhesive sheet was prepared in the same manner as in Comparative Example 1 except that 100 parts by mass of the comparative adhesive composition j was used instead of 100 parts by mass of the adhesive composition a.

(Comparative Example 4)
An adhesive sheet was prepared in the same manner as in Example 1 except that 100 parts by mass of the comparative adhesive composition j was used instead of 100 parts by mass of the adhesive composition a.

[Method for evaluating crush resistance (a method for evaluating whether or not a component contained in an adhesive layer is extruded when a force is applied to an adhesive sheet)]
The adhesive sheet obtained in Examples and Comparative Examples was cut into 5 cm × 5 cm, and the # 38 release film was peeled off to give a 50 μm-thick release film (hereinafter “# 50 release film”) 7 cm × 7 cm Affixed to the center.

  Next, the # 75 release film was peeled off, and a # 50 release film 7 cm × 7 cm was further bonded thereon.

From the upper part of the bonded material, it was allowed to stand at 40 ° C. for 60 minutes under a pressure of 0.4 kg / cm ² per unit area.

Next, the ratio of the area of the adhesive sheet after being left to the area of the adhesive sheet before being left (5 cm × 5 cm = 25 cm ² ) was evaluated according to the following criteria.

  A: The ratio of the area of the adhesive sheet after being left to the area of the adhesive sheet before being left was 100% or more and less than 101%.

  (Circle): The ratio of the area of the adhesive sheet after leaving to the area of the adhesive sheet before leaving was 101% or more and less than 103%.

  Δ: The ratio of the area of the adhesive sheet after being left to the area of the adhesive sheet before being left was from 103% to less than 105%.

  X: The ratio of the area of the adhesive sheet after being left to the area of the adhesive sheet before being left was 105% or more.

(Evaluation method for step following ability)
A panel having a decorative layer (black) having a thickness of 20 μm and a width of 4 mm was prepared on a frame portion of a glass plate having a length of 4 cm and a width of 5 cm.

  The # 50 release film on the pressure-sensitive adhesive layer side constituting the pressure-sensitive adhesive sheet used in the evaluation test for crush resistance is removed, and the surface of the panel (with a decorative layer) is provided on the surface of the pressure-sensitive adhesive layer. The side surface) was affixed.

  Next, the # 50 release film on the adhesive layer side constituting the adhesive sheet was removed, and a polyethylene terephthalate film having a length of 4 cm, a width of 5 cm, and a thickness of 125 μm was stuck to the surface.

The patch was allowed to stand in an environment of 5 atm and 80 ° C. for 20 minutes, and then irradiated with ultraviolet rays of 1000 mJ / cm ² using an electrodeless lamp (fusion lamp H bulb).

  After the irradiation, the interface between the step portion resulting from the decorative layer and the pressure-sensitive adhesive layer constituting the adhesive sheet and its periphery were observed from the panel plate side using an optical microscope, and evaluated according to the following criteria. .

  In addition, evaluation of the adhesive sheet or adhesive sheet of Comparative Examples 1, 2, and 3 consisting of a single layer was performed by the following method. The panel is attached to one side of the pressure-sensitive adhesive layer or adhesive layer constituting the pressure-sensitive adhesive sheet or adhesive sheet used in the crush resistance evaluation test, and the other side of the pressure-sensitive adhesive layer or adhesive layer is polyethylene terephthalate. A film was affixed.

  Next, after irradiating with ultraviolet rays under the same conditions as described above, the interface between the stepped portion caused by the decorative layer and the adhesive layer or pressure-sensitive adhesive layer in contact with the stepped portion and its periphery are optically viewed from the panel plate side. It observed using the microscope and evaluated by the following reference | standard.

<Evaluation by the presence or absence of bubbles>
A: There were no fine bubbles at the interface between the step portion and the adhesive layer.

  ◯: There were very slightly fine bubbles at the interface between the stepped portion and the adhesive layer, but it was at a level where there was no practical problem.

  Δ: Slight bubbles were present at the interface between the step and the adhesive layer.

  X: There were bubbles in the interface between the stepped portion and the adhesive layer and in a range other than the interface.

<Evaluation by appearance>
(Double-circle): There was no unevenness | corrugation resulting from distortion in the interface of the said level | step-difference part and an adhesive layer, and it was excellent in the external appearance.

  ◯: Although the interface between the stepped portion and the adhesive layer was slightly distorted, it had a good appearance.

  (Triangle | delta): There exists an unevenness | corrugation resulting from distortion in the interface of the said level | step-difference part and an adhesive agent layer, and the fall of the some external appearance was confirmed.

  X: Concavities and convexities due to distortion were present at the interface between the stepped portion and the adhesive layer, and a decrease in appearance was confirmed.

[Method for measuring storage modulus]
The storage elastic modulus at each temperature of the adhesive layer (A) and the pressure-sensitive adhesive layer (B) constituting the adhesive sheet or the like is measured using a viscoelasticity tester (manufactured by Rheometrics, trade name: Ares 2KSTD). The test piece was sandwiched between parallel disks, which were the measurement unit of the test machine, and the storage elastic modulus (G ′) at a temperature of 40 ° C. or 70 ° C. and a frequency of 1 Hz was measured and determined. As the test piece used in the above measurement, the one obtained by cutting the adhesive sheet or the like into a circle having a thickness of 1 mm and a diameter of 8 mm was used.

  As shown in Table 2, the adhesive sheets of Examples 1 to 10 had good crush resistance and good followability to the step of the decorative layer. In particular, the pressure-sensitive adhesive sheet in which the ratio of the thickness of the adhesive layer and the pressure-sensitive adhesive layer is within the above-described preferable range can effectively prevent the occurrence of distortion such as wrinkles of the pressure-sensitive adhesive sheet. . On the other hand, bubbles were generated in the adhesive sheets of Comparative Examples 1 to 4 with respect to the level difference of the decorative layer.

DESCRIPTION OF SYMBOLS 1 Glass base material 2 Decorating layer 3 Adhesive sheet 4 Glass panel which comprises a touch sensor panel

Claims (9)

An adhesive sheet in which an adhesive layer (A) and an adhesive layer (B) are laminated, and the storage elastic modulus (G ′) measured at a temperature of 40 ° C. and a frequency of 1.0 Hz of the adhesive layer (A). _a40 ) is 1.0 × 10 ⁴ Pa or more, and the storage elastic modulus (G ′ _a70 ) of the adhesive layer (A) measured at a temperature of 70 ° C. and a frequency of 1 Hz is less than 1.0 × 10 ⁴ Pa. And
The storage elastic modulus (G ′ _b40 ) measured at a temperature of 40 ° C. and a frequency of 1.0 Hz of the pressure-sensitive adhesive layer (B) is 1.0 × 10 ⁴ Pa or more, and the temperature of the pressure-sensitive adhesive layer (B) An adhesive sheet having a storage elastic modulus (G ′ _b70 ) measured at 70 ° C. and a frequency of 1 Hz is 1.0 × 10 ⁴ Pa or more. The pressure-sensitive adhesive sheet according to claim 1, wherein the adhesive layer (A) is a layer containing a polyurethane (a1) having a polymerizable unsaturated double bond. Polyurethane (a1) having an isocyanate group or a hydroxyl group obtained by reacting a polyol (a1-1) containing a polycarbonate polyol and a polyisocyanate (a1-2), the polyurethane (a1) having a polymerizable unsaturated double bond (a1) The adhesive sheet according to claim 2, wherein the adhesive sheet is obtained by reacting ()) and a (meth) acrylic monomer having a functional group capable of reacting with the hydroxyl group or isocyanate group. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer (B) is a layer formed using a composition (b1) containing an acrylic polymer. The thickness of the said adhesive bond layer (A) is the range of 5 micrometers-150 micrometers, and the thickness of the said adhesive layer (B) is the range of 5 micrometers-150 micrometers, Any one of Claims 1-4. The adhesive sheet as described. An article in which the pressure-sensitive adhesive layer (B) constituting the adhesive sheet according to any one of claims 1 to 5 is attached to the surface of an adherend (C) having a stepped portion. The article according to claim 6, wherein the adherend (C) having the step portion is a member in which a decorative layer is provided on a part of the transparent member. The pressure-sensitive adhesive layer (B) constituting the adhesive sheet according to any one of claims 1 to 5 and the surface of the adherend (C) having a stepped portion are pressure-bonded, and then The adhesive layer (A) and the surface of another adherend are pressure-bonded, and then the adhesive layer (A) is cured by irradiating with active energy rays, whereby the temperature is 40 ° C. and the frequency is 1.0 Hz. in the measured storage modulus (G 'at _A'40) of 1.0 × ¹⁰ 4 Pa or more and a storage modulus measured at a temperature 70 ° C. and a frequency 1 Hz (G'_A'70) of 1.0 × The manufacturing method of the articles | goods characterized by forming the adhesive bond layer (A ') which is 10 < ⁴ > Pa or more. The pressure-sensitive adhesive layer (B) constituting the adhesive sheet according to any one of claims 1 to 5 and the surface of the adherend (C) having a stepped portion are pressure-bonded, and then An adhesive layer (A) and the surface of the image display module are pressure-bonded, autoclaved, and then irradiated with active energy rays to cure the adhesive layer (A). The storage elastic modulus (G ′ _a′40 ) measured at 0 Hz and the storage elastic modulus (G ′ _a′70 ) measured at a temperature of 70 ° C. and a frequency of 1 Hz is 1.0 × 10 ⁴ Pa or more. The manufacturing method of the image display apparatus characterized by forming the adhesive bond layer (A ') which is 0x10 < ⁴ > Pa or more.

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