CN113993960A - Adhesive sheet, intermediate laminate, method for producing intermediate laminate, and method for producing product laminate - Google Patents

Adhesive sheet, intermediate laminate, method for producing intermediate laminate, and method for producing product laminate Download PDF

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Publication number
CN113993960A
CN113993960A CN202080044219.5A CN202080044219A CN113993960A CN 113993960 A CN113993960 A CN 113993960A CN 202080044219 A CN202080044219 A CN 202080044219A CN 113993960 A CN113993960 A CN 113993960A
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China
Prior art keywords
adhesive
adhesive composition
adhesive layer
state
low
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CN202080044219.5A
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Chinese (zh)
Inventor
仲野武史
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Nitto Denko Corp
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Nitto Denko Corp
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/16—Layered products comprising a layer of synthetic resin specially treated, e.g. irradiated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/12—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by using adhesives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/0008—Electrical discharge treatment, e.g. corona, plasma treatment; wave energy or particle radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/10—Removing layers, or parts of layers, mechanically or chemically
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/022—Mechanical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/06—Interconnection of layers permitting easy separation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J201/00—Adhesives based on unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/40—Adhesives in the form of films or foils characterised by release liners
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/12—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by using adhesives
    • B32B2037/1253—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by using adhesives curable adhesive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/318—Applications of adhesives in processes or use of adhesives in the form of films or foils for the production of liquid crystal displays
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/326—Applications of adhesives in processes or use of adhesives in the form of films or foils for bonding electronic components such as wafers, chips or semiconductors
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
    • C09J2301/12—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers
    • C09J2301/122—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present only on one side of the carrier, e.g. single-sided adhesive tape
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/302—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Thermal Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Adhesive Tapes (AREA)
  • Laminated Bodies (AREA)

Abstract

The adhesive sheet 1 includes a substrate 2 and an adhesive layer 3 disposed on one surface of the substrate 2. The adhesive layer 3 is formed of an adhesive composition which can be lowered in visible light transmittance at a wavelength of 550nm by external stimulus and which can be irreversibly changed in state between a state of high adhesive force and a state of low adhesive force by external stimulus.

Description

Adhesive sheet, intermediate laminate, method for producing intermediate laminate, and method for producing product laminate
Technical Field
The present invention relates to an adhesive sheet, an intermediate laminate, a method for producing an intermediate laminate, and a method for producing a product laminate, and more particularly, to an adhesive sheet, an intermediate laminate obtained using the adhesive sheet, a method for producing the intermediate laminate, and a method for producing a product laminate obtained using the intermediate laminate.
Background
Conventionally, it has been known to attach a reinforcing film to the surface of an electronic device from the viewpoint of surface protection and impact resistance.
As such a reinforcing film, a reinforcing film is known which includes a pressure-sensitive adhesive layer made of a photocurable composition, and increases the adhesion to an adherend by photocuring the pressure-sensitive adhesive layer after bonding to the adherend (for example, see patent document 1).
When such a reinforcing film is attached to an adherend, reworking is easy because the adhesive strength of the pressure-sensitive adhesive layer before photocuring is small, and the adhesive strength of the pressure-sensitive adhesive layer after photocuring is high, so that the adherend can be reinforced.
Documents of the prior art
Patent document
Patent document 1: japanese patent No. 6467551
Disclosure of Invention
Problems to be solved by the invention
On the other hand, the following requirements are: the entire reinforcing film is not left and a part of the reinforcing film is peeled off.
In such a case, the portion to be left (hereinafter referred to as a left portion) is irradiated with light, and the portion to be peeled (hereinafter referred to as a peeled portion) is not irradiated with light. In this case, the remaining portion can remain as it is because of its strong adhesive force, and the peeled portion can be peeled because of its low adhesive force.
On the other hand, when peeling off a peeled portion, first, the boundary between the remaining portion and the peeled portion is cut off, and the peeled portion is peeled off with the end point of the peeled portion as a starting point.
The invention provides a pressure-sensitive adhesive sheet which can leave or remove only an arbitrary portion by applying an external stimulus to the arbitrary portion after being attached to an adherend, an intermediate laminate obtained using the pressure-sensitive adhesive sheet, a method for producing the intermediate laminate, and a method for producing a product laminate obtained using the intermediate laminate.
Means for solving the problems
The present invention [1] is an adhesive sheet comprising a substrate and an adhesive layer disposed on one surface of the substrate, wherein the adhesive layer is formed from an adhesive composition, the visible light transmittance at a wavelength of 550nm of the adhesive composition can be reduced by an external stimulus, and the adhesive composition can irreversibly change state between a state of high adhesive force and a state of low adhesive force by the external stimulus.
The invention [2] comprises the adhesive sheet according to [1], wherein the external stimulus is irradiation with active energy rays.
The present invention [3] includes the pressure-sensitive adhesive sheet according to the above [1] or [2], wherein the pressure-sensitive adhesive layer is formed of a 1 st pressure-sensitive adhesive composition, the visible light transmittance at a wavelength of 550nm of the 1 st pressure-sensitive adhesive composition can be lowered by irradiation with active energy rays, and the 1 st pressure-sensitive adhesive composition can be irreversibly changed from a state of high adhesive force to a state of low adhesive force by irradiation with active energy rays, and the 1 st pressure-sensitive adhesive composition includes: a polymer, a 1 st photo-curing agent, a photo-polymerization initiator, a compound that develops color by reaction with an acid, and a photo-acid generator.
Invention [4 ]]Comprising the above [3]The adhesive sheet, wherein the adhesive layer before state change has a shear storage modulus G' of 6X 10 at 25 ℃4Pa or more and 9X 104Pa or less, and a shear storage modulus G' of the adhesive layer 3 after the state change at 25 ℃ of 2.00X 106Pa or more and 5.00X 106Pa or less.
The present invention [5] includes the pressure-sensitive adhesive sheet according to [1] or [2], wherein the pressure-sensitive adhesive layer is formed of a2 nd pressure-sensitive adhesive composition, the visible light transmittance at a wavelength of 550nm of the 2 nd pressure-sensitive adhesive composition can be lowered by irradiation with active energy rays, and the 2 nd pressure-sensitive adhesive composition can be irreversibly changed from a state of low adhesive force to a state of high adhesive force by irradiation with active energy rays, and the 2 nd pressure-sensitive adhesive composition includes: a polymer, a2 nd photo-curing agent, a photo-polymerization initiator, a compound that develops color by reaction with an acid, and a photo-acid generator.
Invention [6 ]]Comprising the above [5]]The adhesive sheet, wherein the adhesive layer before the state change has a shear storage modulus G' of 1X 10 at 25 ℃4Pa or more and 1.2X 105Pa or less, and a shear storage modulus G' at 25 ℃ of the adhesive layer after the state change of 1.5X 105Pa or more and 2.0X 106Pa or less.
The invention [7] is an intermediate laminate comprising a pressure-sensitive adhesive sheet and an adherend disposed on one surface of the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet comprising a substrate and a pressure-sensitive adhesive layer disposed on one surface of the substrate, the pressure-sensitive adhesive layer being formed from an adhesive composition, the visible light transmittance of the adhesive composition at a wavelength of 550nm being reducible by an external stimulus, and the adhesive composition being irreversibly changeable in state between a state of high adhesive force and a state of low adhesive force by the external stimulus, the pressure-sensitive adhesive layer comprising a high adhesive region formed from the adhesive composition in the state of high adhesive force and a low adhesive region formed from the adhesive composition in the state of low adhesive force, and either one of the high adhesive region and the low adhesive region having a lower visible light transmittance at a wavelength of 550nm than the other.
The present invention [8] includes the intermediate laminate according to [7], wherein the adhesive layer is formed of a 1 st adhesive composition, the visible light transmittance at a wavelength of 550nm of the 1 st adhesive composition can be decreased by irradiation with active energy rays, the 1 st adhesive composition can be irreversibly changed from a state of high adhesive force to a state of low adhesive force by irradiation with active energy rays, the high adhesive region is formed of the 1 st adhesive composition before the state change, the low adhesive region is formed of the 1 st adhesive composition after the state change, and the visible light transmittance at a wavelength of 550nm of the low adhesive region is smaller than the visible light transmittance at a wavelength of 550nm of the high adhesive region.
The present invention [9] comprises the intermediate laminate according to [7], wherein the adhesive layer is formed of a2 nd adhesive composition, the visible light transmittance at a wavelength of 550nm of the 2 nd adhesive composition can be decreased by irradiation with active energy rays, the 2 nd adhesive composition can be irreversibly changed from a state of low adhesive force by irradiation with active energy rays to a state of high adhesive force, the low adhesive region is formed of the 2 nd adhesive composition before the state change, the high adhesive region is formed of the 2 nd adhesive composition after the state change, and the visible light transmittance at a wavelength of 550nm of the high adhesive region is smaller than the visible light transmittance at a wavelength of 550nm of the low adhesive region.
The present invention [10] is a method for producing an intermediate laminate, including: a step of preparing an adhesive sheet including a substrate and an adhesive layer disposed on one surface of the substrate and formed of an adhesive composition, the adhesive composition having a visible light transmittance at a wavelength of 550nm that can be reduced by an external stimulus, and the adhesive composition being capable of undergoing an irreversible state change between a state of high adhesive force and a state of low adhesive force by the external stimulus; disposing an adherend on one surface of the pressure-sensitive adhesive sheet; and a step of applying the external stimulus to a part of the adhesive layer to form a stimulated part to which the external stimulus is applied and a non-stimulated part to which the external stimulus is not applied in the adhesive layer, whereby either the stimulated part or the non-stimulated part is in a high-adhesion region having a high adhesive force state and the other is in a low-adhesion region having a low adhesive force state, and the visible light transmittance at a wavelength of 550nm of the stimulated part is made smaller than the visible light transmittance at a wavelength of 550nm of the non-stimulated part.
The present invention [11] includes the method for producing an intermediate laminate according to [10], wherein the adhesive layer is formed of a 1 st adhesive composition, the visible light transmittance at a wavelength of 550nm of the 1 st adhesive composition can be reduced by an external stimulus, the 1 st adhesive composition can be irreversibly changed from a state of high adhesive force by the external stimulus to a state of low adhesive force, the stimulated portion is the low adhesive region, and the non-stimulated portion is the high adhesive region.
The present invention [12] includes the method for producing an intermediate laminate according to [10], wherein the adhesive layer is formed of a2 nd adhesive composition, the visible light transmittance at a wavelength of 550nm of the 2 nd adhesive composition can be reduced by an external stimulus, the 2 nd adhesive composition can be irreversibly changed from a state of low adhesive force by the external stimulus to a state of high adhesive force, the stimulated portion is the high adhesive region, and the non-stimulated portion is the low adhesive region.
The present invention [13] includes a method for producing a product laminate, comprising: a step of preparing an intermediate laminate produced by the method for producing an intermediate laminate according to any one of [10] to [12 ]; and removing the low adhesion region in the adhesive layer.
ADVANTAGEOUS EFFECTS OF INVENTION
The adhesive sheet of the present invention includes an adhesive layer formed of an adhesive composition, the visible light transmittance of which at a wavelength of 550nm can be lowered by external stimulus, and the adhesive composition can irreversibly change its state between a state of high adhesive force and a state of low adhesive force by the external stimulus.
When an external stimulus is applied to a part of the pressure-sensitive adhesive sheet, the visible light transmittance at a wavelength of 550nm of the part to which the external stimulus is applied decreases, and the adhesive force changes (the adhesive force increases or decreases).
That is, the portion to which the external stimulus is applied and the portion to which the external stimulus is not applied have different adhesive forces from each other, and visible light transmittance at a wavelength of 550nm is different.
Since the visible light transmittance at a wavelength of 550nm is different between the portion to which the external stimulus is applied and the portion to which the external stimulus is not applied, the boundary between the portion to which the external stimulus is applied and the portion to which the external stimulus is not applied can be visually distinguished easily, and as a result, the portion having relatively low adhesive force can be easily removed from the portion to which the external stimulus is applied and the portion to which the external stimulus is not applied.
In the intermediate laminate of the present invention, the adhesive layer includes a high adhesive region having a high adhesive strength and a low adhesive region having a low adhesive strength, and one of the high adhesive region and the low adhesive region has a lower visible light transmittance at a wavelength of 550nm than the other.
This makes it possible to easily visually distinguish the boundary between the high-adhesion region and the low-adhesion region, and as a result, the low-adhesion region can be easily removed.
The method for producing an intermediate laminate according to the present invention comprises the steps of: by applying an external stimulus to a part of the adhesive layer and forming a stimulated part to which the external stimulus is applied and a non-stimulated part to which the external stimulus is not applied in the adhesive layer, either the stimulated part or the non-stimulated part is a high-adhesion region in a state of high adhesive force and the other is a low-adhesion region in a state of low adhesive force, and the visible light transmittance at a wavelength of 550nm in the stimulated part is made smaller than the visible light transmittance at a wavelength of 550nm in the non-stimulated part.
This makes it possible to produce an intermediate laminate provided with an adhesive layer that includes high-adhesive regions and low-adhesive regions having different adhesive forces from each other and different visible light transmittances at a wavelength of 550 nm.
The method for producing a product laminate of the present invention includes a step of removing a low-adhesion region of the adhesive layer in the intermediate laminate produced by the method for producing an intermediate laminate of the present invention.
Since the low adhesion region has low adhesion, the low adhesion region can be easily removed from the intermediate laminate together with the corresponding substrate. On the other hand, the highly adhesive region remains in the intermediate laminate, and can be used together with the corresponding base material for reinforcing the adherend.
Drawings
Fig. 1 shows a schematic view of an embodiment of the pressure-sensitive adhesive sheet of the present invention.
Fig. 2 is a schematic view showing an embodiment of a method for producing a pressure-sensitive adhesive sheet, in which fig. 2 a shows a 1 st step of preparing a substrate, fig. 2B shows a2 nd step of laminating an adhesive layer on one surface of the substrate, and fig. 2C shows a step of laminating a release film on one surface of the adhesive layer.
Fig. 3 shows a schematic view of an embodiment of an intermediate laminate according to the present invention.
Fig. 4 is a schematic view showing an embodiment of the method for producing an intermediate laminate of the present invention in the case where a pressure-sensitive adhesive layer is formed from the 1 st pressure-sensitive adhesive composition, wherein a in fig. 4 shows the 3 rd step of preparing a pressure-sensitive adhesive sheet, B in fig. 4 shows the 4 th step of disposing an adherend on one surface of the pressure-sensitive adhesive sheet, and C in fig. 4 shows the 5 th step of irradiating a part of the pressure-sensitive adhesive layer with an active energy ray to form a high-adhesion region and a low-adhesion region.
Fig. 5 is a schematic view showing an embodiment of the method for producing an intermediate laminate of the present invention in the case where a pressure-sensitive adhesive layer is formed from the 2 nd pressure-sensitive adhesive composition, wherein a in fig. 5 shows the 3 rd step of preparing a pressure-sensitive adhesive sheet, B in fig. 5 shows the 4 th step of disposing an adherend on one surface of the pressure-sensitive adhesive sheet, and C in fig. 5 shows the 5 th step of irradiating a part of the pressure-sensitive adhesive layer with an active energy ray to form a high-adhesion region and a low-adhesion region.
Fig. 6 is a schematic view showing an embodiment of the method for producing a product laminate of the present invention when an intermediate laminate is prepared by the method for producing an intermediate laminate in which an adhesive layer is formed from the 1 st adhesive composition, wherein a in fig. 6 shows the 6 th step of preparing an intermediate laminate, and B in fig. 6 shows the 7 th step of removing a low-adhesive region in an adhesive layer.
Fig. 7 is a schematic view showing an embodiment of the method for producing a product laminate of the present invention when an intermediate laminate is prepared by the method for producing an intermediate laminate in which an adhesive layer is formed from the 2 nd adhesive composition, wherein a in fig. 7 shows the 6 th step of preparing an intermediate laminate, and B in fig. 7 shows the 7 th step of removing a low-adhesive region in an adhesive layer.
Detailed Description
An embodiment of the pressure-sensitive adhesive sheet of the present invention will be described with reference to fig. 1.
1. Adhesive sheet
As shown in fig. 1, the adhesive sheet 1 has a film shape (including a sheet shape) having a predetermined thickness, and has a flat upper surface and a flat lower surface extending in a direction (surface direction) orthogonal to the thickness direction.
Specifically, the adhesive sheet 1 includes a substrate 2 and an adhesive layer 3 disposed on one surface of the substrate 2.
The layers constituting the pressure-sensitive adhesive sheet 1 will be described below.
1-1. base material
The substrate 2 is a lower layer of the adhesive sheet 1. The substrate 2 is a support layer (support material) that ensures the mechanical strength of the adhesive sheet 1. The base material 2 is a reinforcing material for reinforcing an adherend 6 (described later) in the intermediate laminate 5 (described later). The substrate 2 has a thin film shape extending in the planar direction, and has a flat surface and a flat lower surface.
The substrate 2 is formed from a flexible plastics material.
Examples of such plastic materials include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, (meth) acrylic resins such as polymethacrylate (acrylic resins and/or methacrylic resins), polyolefin resins such as polyethylene, polypropylene, and cycloolefin polymer (COP), polycarbonate resins such as polyether sulfone resins, polyarylate resins such as polyarylate resins, melamine resins such as melamine resins, polyamide resins such as polyamide resins, polyimide resins such as cellulose resins, polystyrene resins such as polystyrene resins, and synthetic resins such as norbornene resins.
As will be described in detail later, when the adhesive layer 3 is cured by irradiation of active energy rays (specifically, ultraviolet rays) from the substrate 2 side, the substrate 2 preferably has transparency to the active energy rays (specifically, ultraviolet rays).
Specifically, the transparency means that the total light transmittance (JIS K7375-2008) is, for example, 85% or more, preferably 90% or more.
From the viewpoint of satisfying both transparency to active energy rays (specifically, ultraviolet rays) and mechanical strength, the plastic material preferably includes a polyester resin, and more preferably includes polyethylene terephthalate (PET).
The thickness of the base material 2 is, for example, 4 μm or more, and is preferably 20 μm or more, more preferably 30 μm or more, and further preferably 45 μm or more, and is, for example, 500 μm or less, from the viewpoint of reinforcing an adherend 6 (described later), and is preferably 300 μm or less, more preferably 200 μm or less, and further preferably 100 μm or less, from the viewpoint of flexibility and handling property.
1-2. adhesive layer
The adhesive layer 3 is disposed on the entire surface of one surface of the substrate 2, and the adhesive layer 3 is an upper layer of the adhesive sheet 1.
The pressure-sensitive adhesive layer 3 is a pressure-sensitive adhesive layer for adhering the pressure-sensitive adhesive sheet 1 to an adherend 6. The adhesive layer 3 has a film shape extending in the planar direction, and has a flat surface and a flat lower surface.
The adhesive layer 3 is formed of an adhesive composition which can be lowered in visible light transmittance at a wavelength of 550nm by external stimulus and which can be irreversibly changed in state between a state of high adhesive force and a state of low adhesive force by external stimulus.
That is, the visible light transmittance at a wavelength of 550nm of the adhesive composition can be lowered by the same external stimulus, and the state change can occur irreversibly between a state of high adhesive force and a state of low adhesive force.
Examples of the external stimulus include irradiation with active energy rays such as electron beam irradiation and ultraviolet irradiation, and heating, for example, and preferably include irradiation with active energy rays, and more preferably ultraviolet irradiation.
When the external stimulation is irradiation with active energy rays, an arbitrary portion can be locally irradiated with active energy rays in the step 5 described later.
When the external stimulus is irradiation with active energy rays, examples of the adhesive composition include: a first adhesive composition which can be reduced in visible light transmittance at a wavelength of 550nm by irradiation with active energy rays and can be irreversibly changed from a state of high adhesive force to a state of low adhesive force by irradiation with active energy rays; and a2 nd adhesive composition which can be reduced in visible light transmittance at a wavelength of 550nm by irradiation with an active energy ray and can be changed in state irreversibly from a state of low adhesive force by irradiation with an active energy ray to a state of high adhesive force.
The 1 st adhesive composition comprises: a polymer, a 1 st photo-curing agent, a photo-polymerization initiator, a compound that develops color by reaction with an acid, and a photo-acid generator.
Specifically, the 1 st adhesive composition contains a polymer as a matrix, contains a 1 st photo-curing agent and a photo-polymerization initiator so as to be irreversibly changed from a state of high adhesive force to a state of low adhesive force by irradiation with active energy rays, and contains a photo-acid generator and a compound that develops color by reaction with an acid so as to decrease visible light transmittance at a wavelength of 550nm by irradiation with active energy rays.
Examples of the polymer include acrylic polymers, silicone polymers, urethane polymers, and rubber polymers, and from the viewpoint of controlling optical transparency, adhesiveness, and storage modulus, acrylic polymers are cited.
The acrylic polymer is obtained by polymerizing a monomer component containing an alkyl (meth) acrylate as a main component.
The alkyl (meth) acrylate is an acrylate and/or a methacrylate, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, and mixtures thereof, Examples of the (meth) acrylic acid include linear or branched C1-20 alkyl (meth) acrylates such as dodecyl (meth) acrylate, isotridecyl (meth) acrylate, tetradecyl (meth) acrylate, isotetradecyl (meth) acrylate, pentadecyl (meth) acrylate, cetyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, and eicosyl (meth) acrylate, and examples thereof include preferably methyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate, and more preferably methyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate.
The alkyl (meth) acrylate may be used singly or in combination of 2 or more.
The alkyl (meth) acrylate is preferably used in combination with methyl methacrylate and C4-12 alkyl (meth) acrylate, or butyl (meth) acrylate alone, and more preferably used in combination with methyl methacrylate and 2-ethylhexyl acrylate, or butyl acrylate alone, from the viewpoint of adjusting the glass transition temperature and the shear storage modulus G'.
When methyl methacrylate and a C4-12 alkyl (meth) acrylate are used in combination as the alkyl (meth) acrylate, the blending ratio of methyl methacrylate is, for example, 5 parts by mass or more and 20 parts by mass or less, and the blending ratio of the C4-12 alkyl (meth) acrylate is, for example, 80 parts by mass or more and 95 parts by mass or less, based on 100 parts by mass of the total amount of methyl methacrylate and the C4-12 alkyl (meth) acrylate.
The blending ratio of the alkyl (meth) acrylate is, for example, 50 mass% or more, preferably 60 mass% or more, and is, for example, 97 mass% or less, preferably 80 mass% or less with respect to the monomer components.
In addition, the monomer component preferably contains a functional group-containing vinyl monomer copolymerizable with the alkyl (meth) acrylate.
Examples of the functional group-containing vinyl monomer include a hydroxyl group-containing vinyl monomer, a carboxyl group-containing vinyl monomer, a nitrogen-containing vinyl monomer, a cyano group-containing vinyl monomer, a glycidyl group-containing vinyl monomer, a sulfo group-containing vinyl monomer, a phosphoric acid group-containing vinyl monomer, an aromatic vinyl monomer, a vinyl ester monomer, and a vinyl ether monomer.
Examples of the hydroxyl group-containing vinyl monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and 4- (hydroxymethyl) cyclohexylmethyl (meth) acrylate, and preferably include 2-hydroxyethyl (meth) acrylate, and more preferably include 2-hydroxyethyl acrylate.
Examples of the carboxyl group-containing vinyl monomer include (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc., preferably (meth) acrylic acid, and more preferably acrylic acid.
Examples of the carboxyl group-containing vinyl monomer include acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride.
Examples of the nitrogen-containing vinyl monomer include N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-acryloylmorpholine, N-vinylcarboxylic acid amides, N-vinylcaprolactam, and the like, and preferable examples thereof include N-vinylpyrrolidone.
Examples of the cyano group-containing vinyl monomer include (meth) acrylonitrile and the like.
Examples of the glycidyl group-containing vinyl monomer include glycidyl (meth) acrylate and the like.
Examples of the sulfo group-containing vinyl monomer include styrene sulfonic acid and allyl sulfonic acid.
Examples of the phosphoric acid group-containing vinyl monomer include 2-hydroxyethyl acryloyl phosphate and the like.
Examples of the aromatic vinyl monomer include styrene, p-methylstyrene, o-methylstyrene, and α -methylstyrene.
Examples of the vinyl ester monomer include vinyl acetate and vinyl propionate.
Examples of the vinyl ether monomer include methyl vinyl ether and the like.
The functional group-containing vinyl monomers may be used singly or in combination of 2 or more. When a crosslinking agent (described later) is blended, from the viewpoint of introducing a crosslinked structure into a polymer, a hydroxyl group-containing vinyl monomer and a carboxyl group-containing vinyl monomer are preferably used, and from the viewpoint of improving the cohesive force, a nitrogen-containing vinyl monomer is preferably used, and a hydroxyl group-containing vinyl monomer and/or a carboxyl group-containing vinyl monomer is more preferably used in combination with a nitrogen-containing vinyl monomer, or a carboxyl group-containing vinyl monomer is used alone.
When the hydroxyl group-containing vinyl monomer and/or the carboxyl group-containing vinyl monomer is used in combination with the nitrogen-containing vinyl monomer, the compounding ratio of the hydroxyl group-containing vinyl monomer and/or the carboxyl group-containing vinyl monomer is, for example, 40 parts by mass or more and, for example, 60 parts by mass or less, and the compounding ratio of the nitrogen-containing vinyl monomer is, for example, 40 parts by mass or more and, for example, 60 parts by mass or less, with respect to 100 parts by mass of the total amount of the hydroxyl group-containing vinyl monomer and/or the carboxyl group-containing vinyl monomer and the nitrogen-containing vinyl monomer.
The blending ratio of the functional group-containing vinyl monomer is, for example, 5 mass% or more, preferably 10 mass% or more, more preferably 15 mass% or more, and, for example, 30 mass% or less with respect to the monomer components.
The acrylic polymer is a polymer obtained by polymerizing the monomer component.
In the polymerization of the monomer component, for example, the monomer component is prepared by mixing an alkyl (meth) acrylate and a functional group-containing vinyl monomer used as needed, and is prepared by a known polymerization method such as solution polymerization, bulk polymerization, or emulsion polymerization.
The polymerization method is preferably a solution polymerization.
In the solution polymerization, for example, a monomer solution is prepared by compounding a monomer component and a polymerization initiator in a solvent, and thereafter the monomer solution is heated.
Examples of the solvent include organic solvents.
Examples of the organic solvent include aromatic hydrocarbon solvents such as toluene, benzene, and xylene, ether solvents such as diethyl ether, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate, and amide solvents such as N, N-dimethylformamide, and ester solvents are preferred, and ethyl acetate is more preferred.
The solvent may be used alone or in combination of 2 or more.
The blending ratio of the solvent is, for example, 100 parts by mass or more, preferably 200 parts by mass or more, and is, for example, 500 parts by mass or less, preferably 300 parts by mass or less, relative to 100 parts by mass of the monomer component.
Examples of the polymerization initiator include peroxide-based polymerization initiators and azo-based polymerization initiators.
Examples of the peroxide-based polymerization initiator include organic peroxides such as peroxy carbonate, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, and peroxyester.
Examples of the azo polymerization initiator include azo compounds such as 2,2 '-azobisisobutyronitrile, 2' -azobis (2-methylbutyronitrile), 2 '-azobis (2, 4-dimethylvaleronitrile), and dimethyl 2, 2' -azobisisobutyrate.
The polymerization initiator is preferably an azo polymerization initiator, and more preferably 2, 2' -azobisisobutyronitrile.
The polymerization initiator may be used singly or in combination of 2 or more.
The blending ratio of the polymerization initiator is, for example, 0.05 parts by mass or more, preferably 0.1 parts by mass or more, and is, for example, 1 part by mass or less, preferably 0.5 parts by mass or less, relative to 100 parts by mass of the monomer component.
The heating temperature is, for example, 50 ℃ to 80 ℃ inclusive, and the heating time is, for example, 1 hour to 8 hours inclusive.
Thereby, the monomer component is polymerized to obtain an acrylic polymer solution containing an acrylic polymer.
The solid content concentration of the acrylic polymer solution is, for example, 20 mass% or more, and is, for example, 80 mass% or less.
The weight average molecular weight of the acrylic polymer is, for example, 100000 or more, preferably 300000 or more, more preferably 500000 or more, and, for example, 5000000 or less, preferably 3000000 or less, more preferably 2000000 or less.
The weight average molecular weight is a value calculated by measuring by GPC (gel permeation chromatography) and converting to polystyrene.
The glass transition temperature (Tg) of the acrylic polymer is, for example, at least-100 ℃, preferably at least-80 ℃, more preferably at least-40 ℃, and, for example, at most-10 ℃, preferably at most-5 ℃, more preferably at most-0 ℃.
The glass transition temperature is a value described in documents, catalogs, and the like, or a value calculated based on the following formula (1) (Fox formula).
1/Tg＝W1/Tg1+W2/Tg2+···+Wn/Tgn (1)
In the above formula (1), Tg represents the glass transition temperature (unit: K) of the polymer (A), and Tgi(i ═ 1,2,. cndot. cndot.) represents the glass transition temperature (unit: K) when monomer i forms a homopolymer, and W represents the glass transition temperature (unit: K) when monomer i forms a homopolymeri(i ═ 1,2,. cndot. cndot.) represents the mass fraction of the monomer i in the total monomer components.
In the 1 st adhesive composition, the blending ratio of the polymer to the total amount of the polymer, the 1 st photocurable agent, the photopolymerization initiator, the compound that develops color by reaction with an acid, and the photoacid generator is, for example, 70% by mass or more, and is, for example, 95% by mass or less, and preferably 85% by mass or less.
The 1 st photocurable agent includes, from the viewpoint of sufficiently reducing the adhesive strength of the adhesive layer 3 by irradiation with active energy rays, polyfunctional (meth) acrylates having a functional group number of 4 or more, preferably 5 or more, and further 6 or less, specifically 4-functional (meth) acrylates such as ditrimethylolpropane tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, and the like, 6-functional (meth) acrylates such as dipentaerythritol poly (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like, preferably 6-functional (meth) acrylates, and more preferably dipentaerythritol hexa (meth) acrylate.
The 1 st photocurable agent may be used singly or in combination of 2 or more.
The 1 st photo-curing agent has a functional group equivalent of, for example, 50g/eq or more, and, for example, 500g/eq or less.
The viscosity of the 1 st photocurable agent at 25 ℃ is, for example, 100 mPas or more, preferably 400 mPas or more, more preferably 1000 mPas or more, further preferably 3000 mPas or more, particularly preferably 4000 mPas or more, most preferably 5000 mPas or more, further preferably 6000 mPas or more, and usually 8000 mPas or less.
The viscosity can be measured by a B-type VISCOMETER, specifically, by using a VISCOMETER (BH type) of the eastern industry, under the conditions of a measurement temperature of 25 ℃, a spindle No. 3, a rotation speed of 10rpm, and a measurement time of 5 minutes.
From the viewpoint of compatibility, the molecular weight of the 1 st photocurable agent is, for example, 1500 or less, preferably 1000 or less, and, for example, 100 or more.
In addition, the 1 st photo-curing agent is preferably selected to be a photo-curing agent compatible with the polymer.
The 1 st photo-curing agent is compatible with the polymer, and can improve the adhesive force of the adhesive layer 3 to be not irradiated with active energy rays (described later).
Specifically, when the difference between the Hansen Solubility Parameter (HSP) of the polymer and the Hansen Solubility Parameter (HSP) of the 1 st photocurable agent is, for example, 4 or less, preferably 3.5 or less, the 1 st photocurable agent is compatible with the polymer, and as a result, the adhesive force of the adhesive layer 3 to which active energy rays are not irradiated (described later) can be improved.
The Hansen Solubility Parameter (HSP) of the polymer is calculated based on the Hansen Solubility Parameter (HSP) of the monomer constituting the polymer.
The compounding ratio of the 1 st photocurable agent is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, and is, for example, 50 parts by mass or less, preferably 40 parts by mass or less, relative to 100 parts by mass of the polymer.
The compounding ratio of the 1 st photo-curing agent is, for example, 5 mass% or more, preferably 10 mass% or more, more preferably 20 mass% or more, and further, for example, 30 mass% or less with respect to the total amount of the polymer, the 1 st photo-curing agent, the photo-polymerization initiator, the compound that develops color by reaction with an acid, and the photo-acid generator.
The photopolymerization initiator accelerates the curing reaction of the 1 st photocurable agent, and is suitably selected depending on the kind of the 1 st photocurable agent, and examples thereof include hydroxy ketones such as 1-hydroxycyclohexyl phenyl ketone, benzoin ethers such as 2, 2-dimethoxy-1, 2-diphenylethane-1-one, benzil dimethyl ketal, amino ketones, acylphosphine oxides, benzophenones, trichloromethyl group-containing triazine derivatives, and other photo radical initiators.
The photopolymerization initiator may be used alone or in combination of 2 or more.
Among such photopolymerization initiators, when a polyfunctional (meth) acrylate is used as the 1 st photocurable agent, a photoradical initiator is preferably used, and a hydroxyketone is more preferably used.
The photopolymerization initiator has a light absorption region of, for example, 300nm or more and, for example, 450nm or less.
The blending ratio of the photopolymerization initiator is, for example, 0.01 part by mass or more, and is, for example, 1 part by mass or less, and preferably 0.5 part by mass or less, relative to 100 parts by mass of the polymer.
The proportion of the photopolymerization initiator to be blended is, for example, 0.01% by mass or more, for example, 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.1% by mass or less, relative to the total amount of the polymer, the 1 st photocurable agent, the photopolymerization initiator, the compound which develops color by reaction with an acid, and the photoacid generator.
The compound which develops color by reaction with an acid is a compound which changes from colorless (transparent) to colored by the acid, and examples thereof include a leuco dye, for example, a triarylmethane dye such as p, p', p ″ -tris (dimethylamino) triphenylmethane, a diphenylmethane dye such as 4, 4-bis-dimethylaminophenyldibenzyl ether, a fluorane dye such as 3-diethylamino-6-methyl-7-chlorofluorane, a spiropyran dye such as 3-methylspirodinaphthopyran, and a rhodamine dye such as rhodamine-B-anilinolactam.
The compound which develops color by reaction with an acid may be used singly or in combination of 2 or more.
The compounding ratio of the compound that develops color by reaction with an acid is, for example, 0.5 parts by mass or more with respect to 100 parts by mass of the polymer, and is preferably 1.5 parts by mass or more from the viewpoint of further lowering the visible light transmittance at a wavelength of 550nm by external stimulus, and is, for example, 5 parts by mass or less, and preferably 2 parts by mass or less.
The compounding ratio of the compound which develops color by reaction with an acid is, for example, 0.1% by mass or more, and is, for example, 5% by mass or less, preferably 1% by mass or less, relative to the total amount of the polymer, the 1 st photocurable agent, the photopolymerization initiator, the compound which develops color by reaction with an acid, and the photoacid generator.
The photoacid generator is a compound that generates an acid upon irradiation with active energy rays, and examples thereof include onium compounds.
Examples of the onium compound include onium cations such as iodonium and sulfonium, and Cl-、Br-、I-、ZnCl3 -、HSO3 -、BF4 -、PF6 -、AsF6 -、SbF6 -、CH3SO3 -、CF3SO3 -、(C6F5)4B-、(C4H9)4B-Salts formed by anions, and the like.
Preferred examples of such onium compounds include sulfonium (onium cation) and (C)6F5)4B-(anionic) salts.
Further, as the photoacid generator, commercially available products can be used, and for example, CPI-310B (made of sulfonium and (C)6F5)4B-Salt formed, made by San-Apro ltd.), and the like.
The photoacid generator may be used alone or in combination of 2 or more.
The mixing ratio of the photoacid generator is, for example, 1 part by mass or more, and is, for example, 20 parts by mass or less, preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, relative to 100 parts by mass of the polymer.
The compounding ratio of the photoacid generator to the total amount of the polymer, the 1 st photocurable agent, the photopolymerization initiator, the compound that develops color by reaction with an acid, and the photoacid generator is, for example, 0.2 mass% or more, and is, for example, 10 mass% or less, and preferably 2 mass% or less.
In addition, in the preparation of the 1 st adhesive composition, a polymer (a polymer solution in the case of preparing a polymer by solution polymerization), the 1 st photocurable agent, a photopolymerization initiator, a compound which develops color by a reaction with an acid, and a photoacid generator are blended and mixed in the above-described proportions.
The 1 st adhesive composition is preferably blended with a crosslinking agent from the viewpoint of introducing a crosslinked structure into a polymer.
Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a carbodiimide crosslinking agent, and a metal chelate crosslinking agent, and preferably include an isocyanate crosslinking agent and an epoxy crosslinking agent.
Examples of the isocyanate crosslinking agent include aliphatic diisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic diisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, and aromatic diisocyanates such as 2, 4-tolylene diisocyanate, 4' -diphenylmethane diisocyanate and xylylene diisocyanate.
Further, as the isocyanate-based crosslinking agent, there may be mentioned a derivative of the above-mentioned isocyanate (for example, isocyanurate-modified product, polyol-modified product, etc.).
As the isocyanate crosslinking agent, commercially available products can be used, and examples thereof include CORONATE L (trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corp.), CORONATE HL (trimethylolpropane adduct of hexamethylene diisocyanate, manufactured by Tosoh Corp.), CORONATE HX (isocyanurate of hexamethylene diisocyanate), TAKENATE D110N (trimethylolpropane adduct of xylylene diisocyanate, manufactured by Mitsui chemical Co., Ltd.), and the like.
Examples of the epoxy-based crosslinking agent include N, N, N ', N' -tetraglycidyl-m-phenylenediamine, diglycidylaniline, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1, 6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol anhydride polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, Resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and the like, and preferable examples thereof include N, N' -tetraglycidyl-m-phenylenediamine.
As the epoxy crosslinking agent, commercially available products can be used, and examples thereof include TETRAD C (N, N, N ', N' -tetraglycidyl-m-phenylenediamine, manufactured by Mitsubishi gas chemical Co., Ltd.).
The crosslinking agent may be used singly or in combination of 2 or more.
When the crosslinking agent is added to the 1 st adhesive composition, a functional group such as a hydroxyl group or a carboxyl group in the polymer reacts with the crosslinking agent to introduce a crosslinked structure into the polymer.
The equivalent weight of the functional group of the crosslinking agent is, for example, 50g/eq or more and, for example, 500g/eq or less.
The blending ratio of the crosslinking agent is, for example, 0.1 part by mass or more, preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, and further preferably 2.0 parts by mass or more, and is, for example, 10 parts by mass or less, preferably 5 parts by mass or less, and more preferably 4 parts by mass or less, relative to 100 parts by mass of the polymer in the case where the crosslinking agent is an isocyanate-based crosslinking agent.
When the crosslinking agent is an epoxy crosslinking agent, the amount is, for example, 0.1 part by mass or more, for example, 2 parts by mass or less, preferably 1 part by mass or less, and more preferably 0.3 part by mass or less from the viewpoint of improving the adhesive strength, relative to 100 parts by mass of the polymer.
When the 1 st adhesive composition contains a crosslinking agent, a crosslinking catalyst may be added to accelerate the crosslinking reaction.
Examples of the crosslinking catalyst include tetra-n-butyl titanate, tetra-isopropyl titanate,
Figure BDA0003414434590000191
And metal-based crosslinking catalysts such as Iron, butyltin oxide, and dioctyltin dilaurate.
The crosslinking catalyst may be used singly or in combination of 2 or more.
The blending ratio of the crosslinking catalyst is, for example, 0.001 parts by mass or more, preferably 0.01 parts by mass or more, and for example, 0.05 parts by mass or less, relative to 100 parts by mass of the polymer.
The adhesive composition 1 may contain, if necessary, various additives such as a silane coupling agent, an adhesion imparting agent, a plasticizer, a softening agent, a deterioration preventing agent, a filler, a colorant, an ultraviolet absorber from the viewpoint of stabilization under fluorescent light or natural light, an antioxidant from the viewpoint of stabilization under fluorescent light or natural light, a surfactant, and an antistatic agent, in a range not to impair the effects of the present invention.
Thus, the 1 st adhesive composition was obtained.
The blending ratio of the polymer is, for example, 50% by mass or more, preferably 70% by mass or more, and is, for example, 90% by mass or less, preferably 80% by mass or less, with respect to the 1 st adhesive composition.
The compounding ratio of the 1 st photocurable agent is, for example, 10% by mass or more, preferably 20% by mass or more, and is, for example, 40% by mass or less, preferably 30% by mass or less, with respect to the 1 st adhesive composition.
The blending ratio of the photopolymerization initiator is, for example, 0.01% by mass or more, and is, for example, 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.1% by mass or less, relative to the 1 st adhesive composition.
The compounding ratio of the compound that develops color by reaction with an acid is, for example, 0.1% by mass or more, and is, for example, 5% by mass or less, preferably 1% by mass or less, relative to the 1 st adhesive composition.
The mixing ratio of the photoacid generator to the 1 st adhesive composition is, for example, 0.2% by mass or more, and is, for example, 10% by mass or less, and preferably 2% by mass or less.
The 2 nd adhesive composition comprises: the above-mentioned polymer, the 2 nd photo-curing agent, the above-mentioned photopolymerization initiator, the above-mentioned compound which develops color by reaction with an acid, and the above-mentioned photo-acid generator.
Specifically, the 2 nd adhesive composition contains a polymer as a matrix, contains a2 nd photo-curing agent and a photo-polymerization initiator so as to be irreversibly changed from a state of low adhesive force to a state of high adhesive force by irradiation with active energy rays, and contains a photo-acid generator and a compound that develops color by reaction with an acid so as to decrease the visible light transmittance at a wavelength of 550nm by irradiation with active energy rays.
The polymer may be the same as the polymer blended in the first adhesive composition 1, and preferably an acrylic polymer.
The polymers may be used singly or in combination of 2 or more.
The compounding ratio of the polymer is the same as that of the polymer compounded in the adhesive composition 1 described above.
The 2 nd photocurable agent includes, from the viewpoint of sufficiently improving the adhesive strength of the adhesive layer 3 by irradiation with active energy rays, polyfunctional (meth) acrylates having a functional group of 2 to 3 inclusive, and specifically, includes 2-functional (meth) acrylates such as polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, bisphenol a ethylene oxide-modified di (meth) acrylate, bisphenol a propylene oxide-modified di (meth) acrylate, alkylene glycol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, pentaerythritol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerol di (meth) acrylate, and the like, ethoxylated isocyanuric acid tri (meth) acrylate, ethylene glycol di (meth) acrylate, and the like, Examples of the 3-functional (meth) acrylate include pentaerythritol tri (meth) acrylate and trimethylolpropane tri (meth) acrylate, and 2-functional (meth) acrylates are preferable, and polyethylene glycol diacrylate and polypropylene glycol diacrylate are more preferable.
The 2 nd photocurable agent may be used singly or in combination of 2 or more. In addition, by using polyethylene glycol diacrylates having different polymerization degrees in combination (for example, a combination of a polyethylene glycol diacrylate having a polymerization degree of 2 or more and 6 or less and a polyethylene glycol diacrylate having a polymerization degree of 10 or more and 16 or less) as the 2 nd photocurable agent, the adhesive force can be reduced.
The equivalent weight of the functional group of the 2 nd photo-curing agent is, for example, 50g/eq or more, and is, for example, 500g/eq or less.
The 2 nd photocurable agent has a viscosity at 25 ℃ of, for example, 5 mPas or more and, for example, 1000 mPas or less.
From the viewpoint of compatibility, the molecular weight of the 2 nd photocurable agent is, for example, 200 or less, and, for example, 1000 or more.
In addition, the 2 nd photo-curing agent is preferably selected to be a photo-curing agent incompatible with the polymer.
The 2 nd photocurable agent is incompatible with the polymer, and can reduce the adhesive force of the adhesive layer 3 to be described later, which is not irradiated with active energy rays.
Specifically, when the difference between the Hansen Solubility Parameter (HSP) of the polymer and the Hansen Solubility Parameter (HSP) of the 2 nd photo-curing agent is, for example, 3 or more, preferably 4 or more, the 2 nd photo-curing agent is incompatible with the polymer, and as a result, the adhesive force of the adhesive layer 3 to which active energy rays are not irradiated (described later) can be reduced.
The compounding ratio of the 2 nd photo-curing agent is the same as the compounding ratio of the 1 st photo-curing agent compounded in the 1 st adhesive composition described above.
Examples of the photopolymerization initiator include the same photopolymerization initiators as those to be blended in the adhesive composition 1, and when a polyfunctional (meth) acrylate is used as the 2 nd photo-curing agent, a photo radical initiator is preferably used, and hydroxy ketones and benzoin ethers are more preferably used.
The photopolymerization initiator may be used alone or in combination of 2 or more.
The compounding ratio of the photopolymerization initiator is the same as that of the photopolymerization initiator compounded in the first adhesive composition 1 described above.
Examples of the compound which develops color by reaction with an acid include the same compounds as those compounded in the 1 st adhesive composition described above and which develop color by reaction with an acid, and preferably include a leuco dye.
The compound which develops color by reaction with an acid may be used singly or in combination of 2 or more.
The compounding ratio of the compound which develops color by reaction with an acid is the same as the compounding ratio of the compound which develops color by reaction with an acid which is compounded in the 1 st adhesive composition described above.
The photoacid generator may be the same as the photoacid generator to be blended in the first adhesive composition 1, and preferably, the photoacid generator may be a mixture of sulfonium (onium cation) and (C)6F5)4B-(anionic) salts.
The photoacid generator may be used alone or in combination of 2 or more.
The mixing ratio of the photoacid generator was the same as that of the photoacid generator mixed in the first adhesive composition described above.
In the preparation of the 2 nd adhesive composition, a polymer (a polymer solution in the case of preparing a polymer by solution polymerization), a2 nd photo-curing agent, a photo-polymerization initiator, a compound which develops color by a reaction with an acid, and a photo-acid generator are blended and mixed in the above-described proportions.
The 2 nd adhesive composition is preferably blended with a crosslinking agent from the viewpoint of introducing a crosslinked structure into a polymer.
The crosslinking agent may be the same crosslinking agent as the crosslinking agent blended in the first adhesive composition 1, and preferably an isocyanate-based crosslinking agent.
The crosslinking agent may be used singly or in combination of 2 or more.
The compounding ratio of the crosslinking agent is the same as that of the crosslinking agent compounded in the first adhesive composition 1 described above.
When the 2 nd adhesive composition contains a crosslinking agent, a crosslinking catalyst may be added to accelerate the crosslinking reaction.
Examples of the crosslinking catalyst include the same crosslinking catalysts as those added to the first adhesive composition 1.
The crosslinking catalyst may be used singly or in combination of 2 or more.
The compounding ratio of the crosslinking catalyst is the same as that of the crosslinking catalyst compounded in the adhesive composition 1 described above.
The 2 nd adhesive composition may contain, if necessary, various additives blended in the 1 st adhesive composition described above within a range not to impair the effects of the present invention.
Thus, the 2 nd adhesive composition was obtained.
The blending ratio of the polymer, the blending ratio of the 2 nd photocurable agent, the blending ratio of the photopolymerization initiator, the blending ratio of the compound which develops color by reaction with an acid, and the blending ratio of the photoacid generator with respect to the 2 nd adhesive composition are the same as those of the 1 st adhesive composition described above.
That is, the adhesive composition (1 st adhesive composition or 2 nd adhesive composition) is common in that it contains a polymer, a photopolymerization initiator, a blending ratio of a compound that develops color by a reaction with an acid, a photoacid generator, a crosslinking agent blended as necessary, a crosslinking catalyst, and various additives, and differs in that: the 1 st adhesive composition contains a 1 st photo-curing agent of a polyfunctional (meth) acrylate having a functional group number of 4 or more, and the 2 nd adhesive composition contains a2 nd photo-curing agent of a polyfunctional (meth) acrylate having a functional group number of 3 or less.
That is, the 1 st adhesive composition or the 2 nd adhesive composition can be selectively prepared by blending any of the 1 st photo-curing agent and the 2 nd photo-curing agent.
Then, the adhesive layer 3 is formed from the 1 st adhesive composition or the 2 nd adhesive composition by a method described later.
The thickness of the pressure-sensitive adhesive layer 3 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more from the viewpoint of adhesiveness, and is, for example, 300 μm or less, preferably 100 μm or less, more preferably 50 μm or less, further preferably 40 μm or less, and particularly preferably 30 μm or less from the viewpoint of handling property.
2. Method for producing adhesive sheet
Next, a method for producing the adhesive sheet 1 will be described with reference to fig. 2.
The method for producing the adhesive sheet 1 comprises: the method includes a 1 st step of preparing a substrate 2 and a2 nd step of disposing an adhesive layer 3 on one surface of the substrate 2.
In the 1 st step, as shown in a of fig. 2, a substrate 2 is prepared.
In the 2 nd step, as shown in fig. 2B, the adhesive layer 3 is disposed on one surface of the substrate 2.
The adhesive layer 3 is disposed on one surface of the substrate 2, and for example, the 1 st adhesive composition or the 2 nd adhesive composition described above is applied on one surface of the substrate 2 and the solvent is dried and removed as necessary.
Examples of the method for applying the 1 st or 2 nd adhesive composition include roll coating, roll lick coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and die coating.
The drying conditions include, for example, a drying temperature of 50 ℃ or higher, preferably 70 ℃ or higher, more preferably 100 ℃ or higher, and 200 ℃ or lower, preferably 180 ℃ or lower, more preferably 150 ℃ or lower, and a drying time of 5 seconds or longer, preferably 10 seconds or longer, and 20 minutes or shorter, preferably 15 minutes or shorter, more preferably 10 minutes or shorter.
Thereby, the adhesive layer 3 was formed on one surface of the substrate 2, and the adhesive sheet 1 including the substrate 2 and the adhesive layer 3 disposed on one surface of the substrate 2 was obtained.
When the 1 st adhesive composition or the 2 nd adhesive composition contains a crosslinking agent, it is preferable to crosslink the adhesive composition by curing simultaneously with the drying removal or after the drying of the solvent (after laminating a release film 4 (described later)) on one surface of the adhesive layer 3.
The curing conditions are appropriately set depending on the kind of the crosslinking agent, and the curing temperature is, for example, 20 ℃ or higher, and, for example, 160 ℃ or lower, and preferably 50 ℃ or lower, and the curing time is, for example, 1 minute or longer, preferably 12 hours or longer, and more preferably 1 day or longer, and, for example, 7 days or shorter.
As described above, the adhesive layer 3 in the adhesive sheet 1 is formed of either the 1 st adhesive composition or the 2 nd adhesive composition.
The 1 st adhesive composition can be reduced in visible light transmittance at a wavelength of 550nm by irradiation with active energy rays, and can be changed in state irreversibly from a state of high adhesive force by irradiation with active energy rays to a state of low adhesive force.
That is, when the adhesive layer 3 formed of the first adhesive composition 1 is irradiated with active energy rays, an acid is generated from the photoacid generator, and the compound that develops color by reaction with the acid develops color (is colored) by the acid, whereby the visible light transmittance at a wavelength of 550nm of the adhesive layer 3 after irradiation with the active energy rays (after the state change) becomes smaller than the visible light transmittance at a wavelength of 550nm of the adhesive layer 3 before irradiation with the active energy rays (before the state change), and the adhesive force of the adhesive layer 3 after irradiation with the active energy rays (after the state change) becomes smaller than the adhesive force of the adhesive layer 3 before irradiation with the active energy rays (before the state change).
Therefore, in the step 5 described later, when a part of the adhesive layer 3 is irradiated with active energy rays, the adhesive layer 3 formed of the 1 st adhesive composition, to which active energy rays are not irradiated, becomes the high adhesive region 10, and the adhesive layer 3 formed of the 1 st adhesive composition, to which active energy rays are irradiated, becomes the low adhesive region 11. In addition, the visible light transmittance at a wavelength of 550nm of the low adhesion region 11 becomes smaller than the visible light transmittance at a wavelength of 550nm of the high adhesion region 10.
Thus, the adhesive layer 3 includes the high adhesive region 10 having a high visible light transmittance at a wavelength of 550nm and the low adhesive region 11 having a low visible light transmittance at a wavelength of 550 nm.
The adhesive force of the adhesive layer 3 (adhesive force of the high adhesive region 10) before the irradiation with the active energy ray (before the state change) is, for example, 5N/25mm or more, preferably 8N/25mm or more, more preferably 10N/25mm or more, and still more preferably 12N/25mm or more.
The adhesive layer 3 before the state change includes a portion which is not irradiated with the active energy ray and has not undergone the state change (the same applies hereinafter).
The adhesive force of the adhesive layer 3 (adhesive force of the low-adhesive region 11) after irradiation with the active energy ray (after state change) is, for example, 4N/25mm or less, and preferably 3N/25mm or less.
When the adhesive force of the high adhesive region 10 is equal to or higher than the lower limit, the high adhesive region 10 remains in a state of being attached to the adherend 6, and can be used for reinforcing the adherend 6 together with the corresponding base material 2.
When the adhesive force of the low-adhesion region 11 is not more than the upper limit, the low-adhesion region 11 can be easily removed from the intermediate laminated body 5 together with the corresponding substrate 2.
The adhesive force is measured in detail by applying the adhesive sheet 1 to a polyimide film at 25 ℃ and performing a 180-degree peel test at a peel speed of 300 mm/min, as described in the examples below.
The shear storage modulus G' of the adhesive layer 3 at 25 ℃ before irradiation with active energy rays (before state change) is, for example, 6X 104Pa or more, preferably 7X 104Pa or more, and, for example, 9X 104Pa or less, preferably 8X 104Pa or less.
The shear storage modulus G' of the adhesive layer 3 (after the state change) after the irradiation with the active energy ray at 25 ℃ is, for example, 2.00X 106Pa or more, preferably 2.50X 106Pa or more, more preferably 3.0X 106Pa or more, and, for example, 5.00X 106Pa or less.
The shear storage modulus G' is measured by dynamic viscoelasticity measurement under the conditions of a frequency of 1Hz, a temperature rise rate of 5 ℃/min, and a temperature range of-50 ℃ to 150 ℃.
The visible light transmittance of the adhesive layer 3 at a wavelength of 550nm before the irradiation with the active energy ray (before the state change) is, for example, 85% or more, and, for example, 99% or less.
The visible light transmittance of the adhesive layer 3 (after the state change) after the irradiation with the active energy ray at a wavelength of 550nm is, for example, 80% or less, and is, for example, 30% or more.
The difference between the visible light transmittance at a wavelength of 550nm of the adhesive layer 3 before irradiation with the active energy ray (before state change) and the visible light transmittance at a wavelength of 550nm of the adhesive layer 3 after irradiation with the active energy ray (after state change) (visible light transmittance at a wavelength of 550nm of the adhesive layer 3 before irradiation with the active energy ray (before state change) -visible light transmittance at a wavelength of 550nm of the adhesive layer 3 after irradiation with the active energy ray (after state change)) is, for example, 5% or more, preferably 10% or more.
When the difference is equal to or greater than the lower limit, the boundary between the high adhesion region 10 and the low adhesion region 11 can be easily visually recognized, and as a result, the low adhesion region 11 can be easily removed.
The average transmittance of the adhesive layer 3 before irradiation with active energy rays (before state change) at 300nm to 700nm is, for example, 80% or more, and is, for example, 99% or less.
The average transmittance of the adhesive layer 3 (after the state change) after the irradiation with the active energy ray at 300nm to 700nm is, for example, 75% or less, and is, for example, 30% or more.
The above-described method for measuring the transmittance is described in detail in examples (the same shall apply hereinafter).
The haze value of the adhesive layer 3 before the irradiation with the active energy ray (before the state change) is, for example, 3% or less, preferably 1% or less.
The haze value of the adhesive layer 3 (after the state change) after the irradiation with the active energy ray is, for example, 5% or less, preferably 3% or less.
On the other hand, the 2 nd adhesive composition can be reduced in visible light transmittance at a wavelength of 550nm by irradiation with active energy rays, and can be irreversibly changed from a state of low adhesive force by irradiation with active energy rays to a state of high adhesive force.
That is, when the adhesive layer 3 formed of such a2 nd adhesive composition is irradiated with active energy rays, an acid is generated from the photoacid generator, and the compound that develops color by reaction with the acid develops color (is colored) by the acid, whereby the visible light transmittance at a wavelength of 550nm of the adhesive layer 3 (after state change) after the irradiation with the active energy rays becomes smaller than the visible light transmittance at a wavelength of 550nm of the adhesive layer 3 (before state change) before the irradiation with the active energy rays, and the adhesive force of the adhesive layer 3 (after state change) after the irradiation with the active energy rays becomes larger than the adhesive force of the adhesive layer 3 (before state change) before the irradiation with the active energy rays.
Therefore, in the step 5 described later, when a part of the adhesive layer 3 is irradiated with active energy rays, the adhesive layer 3 formed of the 2 nd adhesive composition which is not irradiated with active energy rays becomes the low adhesive region 11, and the adhesive layer 3 formed of the 2 nd adhesive composition which is irradiated with active energy rays becomes the high adhesive region 10. In addition, the visible light transmittance at a wavelength of 550nm of the high adhesion region 10 becomes smaller than the visible light transmittance at a wavelength of 550nm of the low adhesion region 11.
Thus, the adhesive layer 3 includes the high adhesive region 10 having a small visible light transmittance at a wavelength of 550nm and the low adhesive region 11 having a large visible light transmittance at a wavelength of 550 nm.
The adhesive force of the adhesive layer 3 (adhesive force of the low-adhesive region 11) before the irradiation with the active energy ray (before the state change) is, for example, 4N/25mm or less, and preferably 1N/25mm or less.
The adhesive force of the adhesive layer 3 (adhesive force of the high-adhesive region 10) after irradiation with the active energy ray (after the state change) is, for example, 5N/25mm or more, preferably 8N/25mm or more, more preferably 10N/25mm or more, and still more preferably 12N/25mm or more.
When the adhesive force of the low adhesive region 11 is not more than the upper limit, the low adhesive region 11 can be easily removed from the intermediate laminated body 5 together with the corresponding substrate 2.
When the adhesive force of the high adhesive region 10 is equal to or higher than the lower limit, the high adhesive region 10 remains in a state of being adhered to the adherend 6, and can be used for reinforcing the adherend 6 together with the corresponding base material 2.
The shear storage modulus G' of the adhesive layer 3 at 25 ℃ before irradiation with active energy rays (before state change) is, for example, 1X 104Pa or more, preferably 5X 104Pa or more, and, for example, 1.2X 105Pa or less, preferably 1X 105Pa or less.
The shear storage modulus G' of the adhesive layer 3 (after the state change) after the irradiation with the active energy ray at 25 ℃ is, for example, 1.00X 105Pa or morePreferably 1.5X 105Pa or more, and, for example, 2.0X 106Pa or less, preferably 1.0X 106Pa or less.
The visible light transmittance of the adhesive layer 3 at a wavelength of 550nm before the irradiation with the active energy ray (before the state change) is, for example, 85% or more, and, for example, 99% or less.
The visible light transmittance of the adhesive layer 3 (after the state change) after the irradiation with the active energy ray at a wavelength of 550nm is, for example, 80% or less, and is, for example, 30% or more.
The difference between the visible light transmittance at a wavelength of 550nm of the adhesive layer 3 before irradiation with the active energy ray (before state change) and the visible light transmittance at a wavelength of 550nm of the adhesive layer 3 after irradiation with the active energy ray (after state change) (visible light transmittance at a wavelength of 550nm of the adhesive layer 3 before irradiation with the active energy ray (before state change) -visible light transmittance at a wavelength of 550nm of the adhesive layer 3 after irradiation with the active energy ray (after state change)) is, for example, 5% or more, preferably 10% or more.
When the difference is equal to or greater than the lower limit, the boundary between the high adhesion region 10 and the low adhesion region 11 can be easily visually recognized, and as a result, the low adhesion region 11 can be easily removed.
The average transmittance of the adhesive layer 3 before irradiation with active energy rays (before state change) at 300nm to 700nm is, for example, 80% or more, and is, for example, 99% or less.
The average transmittance of the adhesive layer 3 (after the state change) after the irradiation with the active energy ray at 300nm to 700nm is, for example, 75% or less, and is, for example, 30% or more.
The haze value of the adhesive layer 3 before the irradiation with the active energy ray (before the state change) is, for example, 3% or less, preferably 1% or less.
The haze value of the adhesive layer 3 (after the state change) after the irradiation with the active energy ray is, for example, 5% or less, preferably 3% or less.
As shown in fig. 2C, the psa sheet 1 may have a release film 4 laminated on one surface of the psa layer 3 as needed.
In this case, the adhesive sheet 1 includes, in order: a substrate 2, an adhesive layer 3 and a release film 4.
Examples of the release film 4 include flexible plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films.
The thickness of the release film 4 is, for example, 3 μm or more, preferably 10 μm or more, and is, for example, 200 μm or less, preferably 100 μm or less, and more preferably 50 μm or less.
The release film 4 is preferably subjected to a release treatment with a silicone-based, fluorine-based, long-chain alkyl-based, fatty acid amide-based, or other release agent or a release treatment with silica powder.
3. Intermediate laminate
As shown in fig. 3, the intermediate laminate 5 has a film shape (including a sheet shape) having a predetermined thickness, and has a flat upper surface and a flat lower surface extending in a direction (surface direction) orthogonal to the thickness direction.
Specifically, the intermediate laminate 5 includes a pressure-sensitive adhesive sheet 1 and an adherend 6 disposed on one surface of the pressure-sensitive adhesive sheet 1, and the pressure-sensitive adhesive sheet 1 includes a substrate 2 and a pressure-sensitive adhesive layer 3 disposed on one surface of the substrate 2.
As will be described in detail later, the intermediate laminate 5 is obtained by attaching the pressure-sensitive adhesive sheet 1 to an adherend 6.
The intermediate laminate 5 is an intermediate member of a product laminate 12 (described later).
Each layer will be described in detail below.
3-1. adhesive sheet
As described above, the adhesive sheet 1 includes the substrate 2 and the adhesive layer 3 disposed on one surface of the substrate 2.
The adhesive layer 3 in the adhesive sheet 1 includes a high adhesive region 10 formed of an adhesive composition having a high adhesive strength and a low adhesive region 11 formed of an adhesive composition having a low adhesive strength.
As will be described in detail later, the visible light transmittance at a wavelength of 550nm is lower in either one of the high-adhesion region 10 and the low-adhesion region 11 than in the other (in other words, the visible light transmittance at a wavelength of 550nm is different between the high-adhesion region 10 and the low-adhesion region 11).
The high adhesion region 10 and the low adhesion region 11 are obtained by applying an external stimulus (specifically, an active energy ray) to a part of the adhesive layer 3, which will be described in detail later.
3-2. adherend
The adherend 6 is a reinforced body reinforced with the pressure-sensitive adhesive sheet 1, and examples thereof include an optical device, an electronic device, and components thereof.
In fig. 3, the adherend 6 has a flat plate shape, but the shape of the adherend 6 is not particularly limited, and various shapes are selected depending on the types of optical devices, electronic devices, and their structural members.
4. Method for producing intermediate laminate
An embodiment of a method for manufacturing the intermediate laminated body 5 will be described with reference to fig. 4 and 5.
The method for manufacturing the intermediate laminate 5 includes: a step (3 rd step) of preparing the adhesive sheet 1; a step (4 th step) of disposing an adherend 6 on one surface of the pressure-sensitive adhesive sheet 1; and a step (5) of applying an external stimulus to a part of the adhesive layer 3, and forming a stimulated part 7 to which the external stimulus is applied and a non-stimulated part 8 to which the external stimulus is not applied in the adhesive layer 3, whereby either the stimulated part 7 or the non-stimulated part 8 has a high adhesive strength, and the other has a low adhesive strength, and the visible light transmittance at a wavelength of 550nm of the stimulated part 7 is made smaller than the visible light transmittance at a wavelength of 550nm of the non-stimulated part 8 (step 5).
In the 5 th step, one of the stimulation portion 7 and the non-stimulation portion 8 is a high adhesion region 10, and the other is a low adhesion region 11, and the adhesive layer 3 is formed of either the 1 st adhesive composition or the 2 nd adhesive composition to determine which of the stimulation portion 7 and the non-stimulation portion 8 is the high adhesion region 10 or the low adhesion region 11.
Therefore, the following description will be made separately for the case where the adhesive layer 3 is formed from the 1 st adhesive composition and the case where the adhesive layer 3 is formed from the 2 nd adhesive composition.
In the following description, the case where the external stimulus is irradiation with active energy rays will be described.
4-1. method for producing intermediate laminate having adhesive layer formed from the 1 st adhesive composition (production method 1)
Referring to fig. 4, a method for producing an intermediate laminate 5 having an adhesive layer 3 formed from the 1 st adhesive composition (production method 1) will be described first.
In the 3 rd step, as shown in a of fig. 4, the adhesive sheet 1 is prepared.
Next, in the 4 th step, as shown in fig. 4B, the pressure-sensitive adhesive sheet 1 is attached to the adherend 6 so that the pressure-sensitive adhesive layer 3 disposed on one surface of the substrate 2 is in contact with the adherend 6.
Next, in the 5 th step, as shown in fig. 4C, a part of the adhesive layer 3 is irradiated with active energy rays, thereby forming a high adhesion region 10 and a low adhesion region 11.
In the following description, 2 portions at both ends of the adhesive sheet 1 divided into 3 in the planar direction will be referred to as non-irritating portions 8 (in other words, only 1 portion at the central portion of the adhesive sheet 1 divided into 3 in the planar direction will be referred to as irritating portions 7).
In the 5 th step, the adhesive sheet 1 is irradiated with active energy rays to the stimulated portions 7 and not irradiated with active energy rays to the non-stimulated portions 8.
Specifically, the mask 9 is not disposed in the stimulation portion 7, and the mask 9 for blocking the active energy ray is disposed in the non-stimulation portion 8.
As described above, when the adhesive layer 3 formed of the 1 st adhesive composition is irradiated with active energy rays, the adhesive force of the adhesive layer 3 after irradiation with active energy rays becomes smaller than the adhesive force of the adhesive layer 3 before irradiation with active energy rays.
That is, the adhesive force of the adhesive layer 3 in the stimulation portion 7 is reduced, while the adhesive layer 3 in the non-stimulation portion 8 is not reduced in adhesive force and remains in a state of strong adhesive force.
In this case, since the adhesive force of the stimulation portion 7 is relatively low with respect to the non-stimulation portion 8, the stimulation portion 7 (specifically, the adhesive layer 3 formed of the 1 st adhesive composition after the state change) becomes the low adhesive region 11, and the non-stimulation portion 8 (specifically, the adhesive layer 3 formed of the 1 st adhesive composition before the state change) becomes the high adhesive region 10.
In addition, in the adhesive layer 3 in the stimulation portion 7 (low adhesion region 11), an acid is generated from the photoacid generator, and a compound that develops color by a reaction with the acid develops color (specifically, black)) by the acid. As a result, the adhesive layer 3 in the stimulation portion 7 (low adhesion region 11) changes from colorless (transparent) to colored (visible light transmittance at a wavelength of 550nm becomes low.). In this case, the visible light transmittance at a wavelength of 550nm of the stimulation portion 7 (low adhesion region 11) becomes smaller than the visible light transmittance at a wavelength of 550nm of the non-stimulation portion 8 (high adhesion region 10) (specifically, the stimulation portion 7 (low adhesion region 11) becomes darker than the non-stimulation portion 8 (high adhesion region 10)), and the boundary between the stimulation portion 7 (low adhesion region 11) and the non-stimulation portion 8 (high adhesion region 10) can be visually recognized easily.
This provides an adhesive layer 3 having high adhesive regions 10 having a high visible light transmittance at a wavelength of 550nm and low adhesive regions 11 having a low visible light transmittance at a wavelength of 550 nm. Further, an intermediate laminate 5 including the pressure-sensitive adhesive sheet 1 and the adherend 6 in this order (in other words, including the substrate 2, the pressure-sensitive adhesive layer 3, and the adherend 6 in this order) was obtained.
4-2. method for producing intermediate laminate having adhesive layer formed from 2 nd adhesive composition (production method 2)
Referring to fig. 5, a method for producing an intermediate laminate 5 in which an adhesive layer 3 is formed from the 2 nd adhesive composition (production method 2) will be described.
In the 3 rd step, as shown in a of fig. 5, the adhesive sheet 1 is prepared.
Next, in the 4 th step, as shown in fig. 5B, the pressure-sensitive adhesive sheet 1 is attached to the adherend 6 so that the pressure-sensitive adhesive layer 3 disposed on one surface of the substrate 2 is in contact with the adherend 6.
Next, in the 5 th step, as shown in C of fig. 5, a part of the adhesive layer 3 is irradiated with active energy rays, thereby forming a high adhesion region 10 and a low adhesion region 11.
In the following description, 2 portions at both ends of the adhesive sheet 1 divided into 3 in the plane direction will be referred to as the irritating portions 7 (in other words, only 1 portion at the central portion of the adhesive sheet 1 divided into 3 in the plane direction will be referred to as the non-irritating portion 8).
In the 5 th step, the adhesive sheet 1 is irradiated with active energy rays to the stimulated portions 7 and not irradiated with active energy rays to the non-stimulated portions 8.
Specifically, the mask 9 is not disposed in the stimulation portion 7, and the mask 9 for blocking the active energy ray is disposed in the non-stimulation portion 8.
As described above, when the adhesive layer 3 formed of the 2 nd adhesive composition is irradiated with the active energy ray, the adhesive force of the adhesive layer 3 after the irradiation with the active energy ray becomes larger than the adhesive force of the adhesive layer 3 before the irradiation with the active energy ray.
That is, the adhesive force of the adhesive layer 3 in the stimulation portion 7 is improved, while the adhesive force of the adhesive layer 3 in the non-stimulation portion 8 is not improved.
In this case, since the adhesive force of the stimulation portion 7 is relatively high with respect to the non-stimulation portion 8, the stimulation portion 7 (specifically, the adhesive layer 3 formed of the 2 nd adhesive composition after the state change) becomes the high adhesive region 10, and the non-stimulation portion 8 (specifically, the adhesive layer 3 formed of the 2 nd adhesive composition before the state change) becomes the low adhesive region 11.
In addition, in the adhesive layer 3 of the stimulation portion 7 (high adhesion region 10), an acid is generated from the photoacid generator, and a compound that develops color by a reaction with the acid develops color (specifically, black)) by the acid. As a result, the adhesive layer 3 of the stimulation portion 7 (high-adhesion region 10) changes from colorless (transparent) to colored (visible light transmittance at a wavelength of 550nm becomes low.). In this case, the visible light transmittance at a wavelength of 550nm of the stimulation portion 7 (high adhesion region 10) becomes smaller than the visible light transmittance at a wavelength of 550nm of the non-stimulation portion 8 (low adhesion region 11) (specifically, the stimulation portion 7 (high adhesion region 10) becomes darker than the non-stimulation portion 8 (low adhesion region 11)), and the boundary between the stimulation portion 7 (high adhesion region 10) and the non-stimulation portion 8 (low adhesion region 11) can be visually recognized easily.
This provides an adhesive layer 3 having high adhesive regions 10 having a low visible light transmittance at a wavelength of 550nm and low adhesive regions 11 having a high visible light transmittance at a wavelength of 550 nm. Further, an intermediate laminate 5 including the pressure-sensitive adhesive sheet 1 and the adherend 6 in this order (in other words, including the substrate 2, the pressure-sensitive adhesive layer 3, and the adherend 6 in this order) was obtained.
The above-mentioned production method 1 and the above-mentioned production method 2 are common in that the visible light transmittance at a wavelength of 550nm of the stimulation portion 7 is smaller than the visible light transmittance at a wavelength of 550nm of the non-stimulation portion 8 (in other words, the stimulation portion 7 is colored, and the non-stimulation portion 8 is transparent), but are different in the following points; in the method 1, the stimulation portion 7 is a low adhesion region 11, and in the method 2, the non-stimulation portion 8 is a low adhesion region 11.
In the method for producing the product laminate 12 described later, the intermediate laminate 5 is first produced, and then the product laminate 12 (described later) is produced by removing the low-adhesion region 11 from the intermediate laminate 5 and leaving the high-adhesion region 10, but the method differs in the following points: the transparent high-adhesion regions 10 remain when the intermediate laminate 5 is produced by the production method 1, and the colored high-adhesion regions 10 remain when the intermediate laminate 5 is produced by the production method 2.
That is, the colored or transparent high-adhesion region 10 can be selected to remain by selecting either one of the manufacturing methods 1 and 2.
5. Adhesive sheet, intermediate laminate, and method for producing intermediate laminate
In the adhesive sheet 1, the adhesive layer 3 is formed of an adhesive composition which can be lowered in visible light transmittance at a wavelength of 550nm by irradiation with active energy rays and which can be irreversibly changed in state between a state of high adhesive force and a state of low adhesive force by irradiation with active energy rays.
When a part of the adhesive sheet 1 is irradiated with active energy rays, the visible light transmittance at a wavelength of 550nm of the part irradiated with active energy rays is lowered, and the adhesive force is changed (the adhesive force is increased or decreased).
That is, the portion irradiated with the active energy ray and the portion not irradiated with the active energy ray are different in adhesive force from each other, and the visible light transmittance at a wavelength of 550nm is different.
Since the transmittance of visible light at 550nm is different between the wavelength of the portion irradiated with the active energy ray and the wavelength of the portion not irradiated with the active energy ray, the boundary between the portion irradiated with the active energy ray and the portion not irradiated with the active energy ray can be visually distinguished easily, and as a result, the portion having relatively low adhesion can be easily removed from the portion irradiated with the active energy ray and the portion not irradiated with the active energy ray.
In the intermediate laminate 5, the adhesive layer 3 includes a high adhesive region 10 in a state of high adhesive force and a low adhesive region 11 in a state of low adhesive force.
In addition, the visible light transmittance at a wavelength of 550nm is smaller in either one of the high-adhesion region 10 and the low-adhesion region 11 than in the other.
Specifically, in the above-described method for producing the intermediate laminate 5, when the adhesive layer is formed from the 1 st adhesive composition, the visible light transmittance at a wavelength of 550nm in the low adhesive region 11 is lower than the visible light transmittance at a wavelength of 550nm in the high adhesive region 10, and when the adhesive layer is formed from the 2 nd adhesive composition, the visible light transmittance at a wavelength of 550nm in the high adhesive region 10 is lower than the visible light transmittance at a wavelength of 550nm in the low adhesive region 11.
This makes it possible to visually distinguish the boundary between the high adhesion region 10 and the low adhesion region 11. As a result, the low adhesion region 11 can be removed from the adherend 6 together with the corresponding base material 2, and the high adhesion region 10 remains in a state of being attached to the adherend 6, and can be used for reinforcing the adherend 6 together with the corresponding base material 2.
As a result, a product laminate 12 (described later) in which the adherend 6 is reinforced can be obtained.
In addition, according to the intermediate laminate 5, the high-adhesion region 10 and the low-adhesion region 11 having different adhesive forces from each other by the same external stimulus (specifically, irradiation with an active energy ray) and having different visible light transmittances at a wavelength of 550nm are formed to have both of them.
In addition, according to the intermediate laminate 5, the high adhesion region 10 and the low adhesion region 11 are not simultaneously formed by forming the high adhesion region 10 with the adhesive composition having high adhesion and forming the low adhesion region 11 with the adhesive composition having low adhesion, but the high adhesion region 10 and the low adhesion region 11 can be simultaneously formed by forming the adhesive composition having the same composition.
The method for producing the intermediate laminate 5 includes the steps of: a part of the adhesive layer 3 is irradiated with an active energy ray, a stimulation part 7 irradiated with the active energy ray and a non-stimulation part 8 not irradiated with the active energy ray are formed in the adhesive layer 3, a high adhesion region 10 where one of the stimulation part 7 and the non-stimulation part 8 has a high adhesive force and a low adhesion region 11 where the other one has a low adhesive force are formed, and the visible light transmittance at a wavelength of 550nm of the stimulation part 7 is made smaller than the visible light transmittance at a wavelength of 550nm of the non-stimulation part 8.
This makes it possible to produce an intermediate laminate 5 provided with an adhesive layer 3, the adhesive layer 3 having a high adhesive region 10 and a low adhesive region 11 that have different adhesive forces from each other and have different visible light transmittances at a wavelength of 550 nm.
6. Product laminate and method for manufacturing product laminate
The product stack 12 is a device in its final form or a component of the device.
Next, an embodiment of a method for manufacturing the product laminate 12 will be described with reference to fig. 6 and 7.
The product laminate 12 is manufactured by removing the low adhesion region 11 from the intermediate laminate 5 described above.
Specifically, the product laminate 12 is produced by a production method for a product laminate, the production method including: the method includes a6 th step of preparing the intermediate laminate 5 manufactured by the method for manufacturing the intermediate laminate 5, and a 7 th step of removing the low-adhesion region 11 in the adhesive layer 3.
In the 6 th step, the intermediate laminate 5 produced by the above-described method for producing the intermediate laminate 5 is prepared, but as described above, whether the remaining high-adhesion region 10 is colored or transparent is determined by selecting either one of the production methods 1 and 2.
Therefore, the following description will be divided into a case of preparing the intermediate laminate 5 manufactured by the manufacturing method 1 and a case of preparing the intermediate laminate 5 manufactured by the manufacturing method 2.
6-1. preparation of intermediate laminate 5 produced by Process 1
Description is made of a method for producing a product laminate 12 in the case of preparing an intermediate laminate 5 produced by the production method 1, with reference to fig. 6.
In the 6 th step, as shown in a of fig. 6, the intermediate laminate 5 is produced by the method for producing the intermediate laminate 5 in which the adhesive layer 3 is formed from the 1 st adhesive composition (production method 1), and the intermediate laminate 5 is prepared.
In the 7 th step, as shown in B of fig. 6, the low adhesion region 11 is removed from the intermediate laminated body 5.
In particular, by means of, for example, CO2The laser or the like cuts the boundary including the high adhesion region 10 and the remaining portion 13 of the substrate 2 corresponding thereto and the boundary including the low adhesion region 11 and the removed portion 14 of the substrate 2 corresponding thereto, and then peels off only the removed portion 14 starting from the end of the removed portion 14.
At this time, since the high-adhesion region 10 (remaining portion 13) and the low-adhesion region 11 (removed portion 14) have different visible light transmittances at a wavelength of 550nm (specifically, the high-adhesion region 10 (remaining portion 13) is transparent and the low-adhesion region 11 (removed portion 14) is colored), the above-described boundary can be easily visually recognized.
Moreover, the adhesive force of the low-adhesion area 11 in the removed portion 14 is reduced, and therefore the removed portion 14 can be easily peeled off from the intermediate laminate 5.
On the other hand, the high adhesive force of the high adhesive region 10 in the remaining portion 13 is not reduced, but has the above-described high adhesive force, and therefore the remaining portion 13 remains in the intermediate laminated body 5.
Further, since the highly adhesive region 10 has the above-described high adhesive force, even if the removed portion 14 is peeled off, the end of the remaining portion 13 in contact with the removed portion 14 can be suppressed from floating.
Further, the remaining portion 13 can be directly used for reinforcement of the adherend 6.
Thereby, a product laminated body 12 was obtained.
Since the remaining portion 13 of the product laminate 12 is transparent, it can be suitably used for an optical device and its constituent members which require transparency.
6-2 cases where intermediate laminate 5 produced by Process 2 was prepared
Referring to fig. 7, a method for manufacturing the product laminate 12 in the case of preparing the intermediate laminate 5 manufactured by the manufacturing method 2 will be described.
In the 6 th step, as shown in a of fig. 7, the intermediate laminate 5 is produced by the method for producing the intermediate laminate 5 in which the adhesive layer 3 is formed from the 2 nd adhesive composition (production method 2), and the intermediate laminate 5 is prepared.
In the 7 th step, as shown in fig. 7B, the low-adhesion region 11 is removed from the intermediate laminated body 5.
In particular, by means of, for example, CO2The laser or the like cuts the boundary including the high adhesion region 10 and the remaining portion 13 of the substrate 2 corresponding thereto and the boundary including the low adhesion region 11 and the removed portion 14 of the substrate 2 corresponding thereto, and then peels off only the removed portion 14 starting from the end point of the removed portion 14.
At this time, since the high-adhesion region 10 (remaining portion 13) and the low-adhesion region 11 (removed portion 14) have different visible light transmittances at a wavelength of 550nm (specifically, the high-adhesion region 10 (remaining portion 13) is colored, and the low-adhesion region 11 (removed portion 14) is transparent), the above-described boundary can be easily visually recognized.
Moreover, the adhesive force of the low-adhesion area 11 in the removed portion 14 is reduced, and therefore the removed portion 14 can be easily peeled off from the intermediate laminate 5.
On the other hand, the high adhesive force of the high adhesive region 10 in the remaining portion 13 is not reduced, but has the above-described high adhesive force, and therefore the remaining portion 13 remains in the intermediate laminated body 5.
Further, since the highly adhesive region 10 has the above-described high adhesive force, even if the removed portion 14 is peeled off, the end of the remaining portion 13 in contact with the removed portion 14 can be suppressed from floating.
Further, the remaining portion 13 can be directly used for reinforcement of the adherend 6.
Thereby, a product laminated body 12 was obtained.
In the product laminate 12, the remaining portion 13 is colored, and therefore can be used as an antireflection layer.
7. Effects of the method for producing a product laminate
The method for producing the product laminate 12 includes a 7 th step of removing the low-adhesion region 11 of the adhesive layer 3 in the intermediate laminate 5 produced by the above-described method for producing an intermediate laminate (the method for producing the intermediate laminate 5 in which the adhesive layer 3 is formed from the 1 st adhesive composition (production method 1) or the method for producing the intermediate laminate 5 in which the adhesive layer 3 is formed from the 2 nd adhesive composition (production method 2)).
The adhesive force in the low-adhesion region 11 is low, and therefore the removal portion 14 can be easily removed from the intermediate laminate 5.
Further, since the high adhesion region 10 (remaining portion 13) and the low adhesion region 11 (removed portion 14) have different visible light transmittances at a wavelength of 550nm, the boundary between the remaining portion 13 and the removed portion 14 can be easily visually recognized. As a result, the removed portion 14 can be reliably removed from the adherend 6.
On the other hand, the remaining portion 13 remains in the intermediate laminate 5, and can reinforce the adherend 6.
Further, since appropriate rigidity is imparted by the remaining portion 13, the handleability is improved.
In particular, in the case where the adherend 6 is an electronic device, the electronic device tends to be as follows: with the high integration, the reduction in size and weight, and the thinning of the constituent members, the thickness of the constituent members of the electronic device becomes smaller. This thinning makes it easier to cause bending and curling due to stress at the lamination interface of the component members. Further, the reduction in thickness makes it easy to cause deflection due to its own weight.
Even in such a case, if the adhesive sheet 1 is used, since rigidity can be imparted to the electronic component by the remaining portion 13, bending, curling, bending, or the like due to stress, self weight, or the like can be suppressed, and handling properties can be improved.
In addition, in the case where the electronic component is conveyed and processed by an automated apparatus in the manufacturing process of the electronic component, the components of the electronic component may come into contact with members such as a conveying arm and a pin, and the components may be damaged.
In particular, in a highly integrated, small, lightweight, and thin device, when a contact or cutting process is performed on a conveyor or the like, damage or dimensional change due to local stress concentration may occur.
Even in such a case, if the adhesive sheet 1 is used, appropriate rigidity can be imparted by the remaining portion 13, and stress can be relaxed and dispersed, so that cracks, peeling, dimensional changes, and the like can be suppressed.
8. Modification example
In the above description, the case where the external stimulus is irradiation with active energy rays has been described, but the external stimulus may be heating.
When the external stimulus is heat, the adhesive layer 3 is formed of an adhesive composition whose visible light transmittance at a wavelength of 550nm can be lowered by the heat, and which can irreversibly change its state between a state of high adhesive force and a state of low adhesive force by the heat.
The adhesive composition includes a 3 rd adhesive composition which can be heated to lower the visible light transmittance at a wavelength of 550nm and can be irreversibly changed from a state of low adhesive force by heating to a state of high adhesive force.
The 3 rd adhesive composition comprises: the polymer, the organosiloxane-containing component, the compound that develops color by reaction with an acid, and the thermal acid generator.
Examples of the organosiloxane-containing component include acrylic polymers having an organosiloxane skeleton, urethane polymers, polyether polymers, polyester polymers, polycarbonate polymers, and polybutadiene polymers, and acrylic polymers having an organosiloxane skeleton are preferred from the viewpoint of controlling adhesion.
The thermal acid generator is a compound that generates an acid by heating, and examples thereof include an aryl sulfonium salt and an aryl iodonium salt.
Examples
The present invention will be described more specifically below with reference to examples and comparative examples. The present invention is not limited to any examples and comparative examples. Specific numerical values such as the blending ratio (content ratio), the physical property value, and the parameter used in the following description may be replaced with upper limit values (numerical values defined as "lower" or "lower") or lower limit values (numerical values defined as "upper" or "lower" or "upper" or "lower") described in the above-described "embodiment" in accordance with the blending ratio (content ratio), the physical property value, and the parameter described in the above-described "embodiment".
Unless otherwise specified, "part(s)" and "%" are based on mass.
1. Details of the ingredients
The components used in the examples and comparative examples are described below.
TAKENATE D110N: preparation of Tri-well chemical from 75% ethyl acetate solution of trimethylolpropane adduct of xylylenediisocyanate
TETRAD C: n, N, N ', N' -tetraglycidyl m-phenylenediamine (4-functional epoxy Compound, manufactured by Mitsubishi gas Chemicals)
A-DPH: dipentaerythritol hexaacrylate; functional group equivalent 96g/eq
APG 700: polypropylene glycol #700 (n-12) diacrylate; functional group equivalent 404g/eq
A200: polyethylene glycol #200(n ═ 4) diacrylate; functional group equivalent of 154g/eq
A600: polyethylene glycol #600(n ═ 14) diacrylate; functional group equivalent 354g/eq
IRGACURE 184: 1-Hydroxycyclohexylphenylketone, preparation of BASF
IRGACURE 651: 2, 2-dimethoxy-1, 2-diphenylethan-1-one
BLACK ND 1: leuco dye, Shantian chemical industry preparation
CPI-310B: comprising sulfonium and (C)6F5)4B-Salt, photoacid generator, San-Apro Ltd
2. Preparation of polymers
Synthesis example 1
In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube, 9 parts by weight of Methyl Methacrylate (MMA), 63 parts by weight of 2-ethylhexyl acrylate (2EHA), 13 parts by weight of hydroxyethyl acrylate (HEA), 15 parts by weight of N-vinylpyrrolidone (NVP), 0.2 part by weight of azobisisobutyronitrile as a polymerization initiator and 233 parts by weight of ethyl acetate as a solvent were charged as monomers, and nitrogen gas was circulated and replaced with nitrogen gas for about 1 hour while stirring. Thereafter, the mixture was heated to 60 ℃ and reacted for 7 hours to obtain a solution of an acrylic polymer having a weight average molecular weight (Mw) of 1200000.
Synthesis example 2
In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube, 95 parts of n-Butyl Acrylate (BA) and 5 parts of Acrylic Acid (AA) as monomer components were charged, nitrogen gas was introduced and circulated, and nitrogen gas substitution was performed for 2 hours while stirring. Then, 0.2 part of 2, 2' -Azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and solution polymerization was performed at 60 ℃ for 8 hours to obtain a solution of an acrylic polymer having a weight average molecular weight (Mw) of 600000.
3. Preparation of adhesive composition
Preparation example 1 (preparation of adhesive composition 1.)
To the acrylic polymer solution of synthetic example 1, TAKENATE D110N (75% ethyl acetate solution of trimethylolpropane adduct of xylylenediisocyanate, manufactured by Mitsui Chemicals) as a crosslinking agent (2.5 parts by mass per 100 parts by weight of the solid content of the polymer), A-DPH (dipentaerythritol hexaacrylate) as a light curing agent (30 parts by mass per 100 parts by weight of the solid content of the polymer), IRGACURE 184 (1-hydroxycyclohexylphenyl ketone, manufactured by BASF) as a photopolymerization initiator (0.1 part by mass per 100 parts by weight of the solid content of the polymer), BLND ACK 1 (leuco dye) as a compound which develops color by reaction with an acid (1 part by mass per 100 parts by weight of the solid content of the polymer), and CP-310B as a photo-acid generator (2 parts by mass per 100 parts by weight of the solid content of the polymer were added, the resultant was uniformly mixed to prepare an adhesive composition (1 st adhesive composition).
Preparation example 2 (preparation of 2 nd adhesive composition)
An adhesive composition (2 nd adhesive composition) was prepared in the same manner as in preparation example 1, except that the light-curing agent was changed to APG700 (polypropylene glycol #700 (n-12) diacrylate).
Preparation examples 3 to 10
An adhesive composition was produced in the same manner as in production example 1, except that the compounding recipe was changed as described in table 1.
4. Production of adhesive sheet
Example 1
The adhesive composition of preparation example 1 was applied to the upper surface of a polyethylene terephthalate film (thickness 75 μm) as a substrate by a spray roller (Fountain roll) so that the thickness after drying became 25 μm. Subsequently, the solvent was removed by drying at 130 ℃ for 1 minute. Thereby, an adhesive layer is formed on one surface of the substrate. Further, a release-treated surface of a release film (a polyethylene terephthalate film having a thickness of 25 μm whose surface was subjected to silicone release treatment) was bonded to one surface of the adhesive layer. Thereafter, the polymer was cured at 25 ℃ for 4 days to effect a crosslinking reaction between the polymer and the crosslinking agent. Thereby, an adhesive sheet was produced.
Examples 2 to 7 and comparative examples 1 to 3
Adhesive sheets were produced in the same manner as in example 1, except that the adhesive composition was changed as described in table 1.
5. Evaluation of
(transmittance)
The adhesive sheets of examples and comparative examples were measured for their transmittance at 550nm before and after irradiation with LED (365nm, 4000mJ/□), and for their average transmittance at 300nm to 700 nm.
The results are shown in table 1.
(adhesive force)
A polyimide film having a thickness of 25 μm was attached to a glass plate with a double-sided adhesive tape (No. 531, manufactured by Rido electric Co., Ltd.) to obtain a polyimide film substrate for measurement. Next, the release film was removed from the pressure-sensitive adhesive sheets of examples and comparative examples, and the pressure-sensitive adhesive sheets were bonded to the polyimide film substrate for measurement at 25 ℃ by a hand pressure roller to prepare samples for measurement.
Then, the sample was left at 25 ℃ and 50% relative humidity for 30 minutes, and then the adhesive force (adhesive force before UV irradiation) was measured.
Further, a sample for measurement was prepared in the same manner as described above, and the sample for measurement was left to stand at 25 ℃ and 50% relative humidity for 30 minutes, then irradiated with an LED (365nm, 4000mJ/□) from the substrate side of the pressure-sensitive adhesive sheet, and further left to stand at 25 ℃ and 50% relative humidity for 30 minutes, and then measured for the adhesive force (adhesive force after UV irradiation).
For the measurement of the adhesive force, the edge of the test sample (edge of the adhesive sheet) was held by a chuck, and 180 ° peeling of the reinforcing film was performed at a stretching speed of 300 mm/min to measure the peel strength. The results are shown in table 1.
[ Table 1]
Figure BDA0003414434590000451
The present invention is provided as an exemplary embodiment of the present invention, but this is merely a simple example and is not to be construed as limiting. Variations of the present invention that are obvious to those skilled in the art are encompassed by the foregoing claims.
Industrial applicability
The adhesive sheet of the present invention is suitably used as a reinforcing adhesive sheet to be bonded to the surface of various devices such as optical devices and electronic devices.
The intermediate laminate, the method for producing the intermediate laminate, and the method for producing the product laminate according to the present invention are suitably used for various devices such as optical devices and electronic devices.
Description of the reference numerals
1 pressure-sensitive adhesive sheet
2 base material
3 adhesive layer
5 intermediate laminate
6 adherend
7 stimulation moiety
8 non-stimulating part
10 high adhesion area
11 low adhesion area
12 product laminate

Claims (13)

1. An adhesive sheet comprising a substrate and an adhesive layer disposed on one surface of the substrate,
the adhesive layer is formed of an adhesive composition that can be reduced in visible light transmittance at a wavelength of 550nm by an external stimulus, and that can be irreversibly changed in state between a state of high adhesive force and a state of low adhesive force by the external stimulus.
2. The adhesive sheet according to claim 1, wherein the external stimulus is irradiation of active energy rays.
3. The adhesive sheet according to claim 1, wherein the adhesive layer is formed from a 1 st adhesive composition, the visible light transmittance at a wavelength of 550nm of the 1 st adhesive composition is reduced by irradiation with active energy rays, and the 1 st adhesive composition is irreversibly changed from a state of high adhesive force to a state of low adhesive force by irradiation with active energy rays,
the 1 st adhesive composition comprises: a polymer, a 1 st photo-curing agent, a photo-polymerization initiator, a compound that develops color by reaction with an acid, and a photo-acid generator.
4. The adhesive sheet according to claim 3, wherein the adhesive layer before state change has a shear storage modulus G' of 6X 10 at 25 ℃4Pa or more and 9X 104The content of the compound is less than Pa,
the adhesive layer 3 after the state change had a shear storage modulus G' of 2.00X 10 at 25 deg.C6Pa or more and 5.00X 106Pa or less.
5. The adhesive sheet according to claim 1, wherein the adhesive layer is formed of a2 nd adhesive composition, the visible light transmittance at a wavelength of 550nm of the 2 nd adhesive composition is decreased by irradiation with active energy rays, and the 2 nd adhesive composition is irreversibly changed from a state of low adhesive force by irradiation with active energy rays to a state of high adhesive force,
the 2 nd adhesive composition comprises: a polymer, a2 nd photo-curing agent, a photo-polymerization initiator, a compound that develops color by reaction with an acid, and a photo-acid generator.
6. The adhesive sheet according to claim 5, wherein the adhesive layer before a state change has a shear storage modulus G' of 1X 10 at 25 ℃4Pa or more and 1.2X 105The content of the compound is less than Pa,
the adhesive layer after the state change has a shear storage modulus G' of 1.5X 10 at 25 DEG C5Pa or more and 2.0X 106Pa or less.
7. An intermediate laminate comprising a pressure-sensitive adhesive sheet and an adherend disposed on one surface of the pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive sheet comprises a substrate and a pressure-sensitive adhesive layer disposed on one surface of the substrate,
the adhesive layer is formed of an adhesive composition which can be reduced in visible light transmittance at a wavelength of 550nm by an external stimulus and which can be irreversibly changed in state between a state of high adhesive force and a state of low adhesive force by the external stimulus,
the adhesive layer comprises a high adhesive region formed by the adhesive composition with high adhesive force and a low adhesive region formed by the adhesive composition with low adhesive force,
either one of the high adhesion region and the low adhesion region has a visible light transmittance at a wavelength of 550nm smaller than that of the other.
8. The intermediate laminate according to claim 7, wherein the adhesive layer is formed from a 1 st adhesive composition, the visible light transmittance at a wavelength of 550nm of the 1 st adhesive composition can be reduced by irradiation with active energy rays, and the 1 st adhesive composition can be irreversibly changed from a state of high adhesive force to a state of low adhesive force by irradiation with the active energy rays,
the high adhesion region is formed of the 1 st adhesive composition before the state change,
the low adhesion region is formed of the 1 st adhesive composition after the state change,
the visible light transmittance at a wavelength of 550nm of the low adhesion region is smaller than the visible light transmittance at a wavelength of 550nm of the high adhesion region.
9. The intermediate laminate according to claim 7, wherein the adhesive layer is formed from a2 nd adhesive composition, the visible light transmittance at a wavelength of 550nm of the 2 nd adhesive composition can be reduced by irradiation with active energy rays, and the 2 nd adhesive composition can be irreversibly changed from a state of low adhesive force to a state of high adhesive force by irradiation with active energy rays,
the low adhesion region is formed of the 2 nd adhesive composition before the state change,
the high adhesion region is formed of the 2 nd adhesive composition after the state change,
the visible light transmittance at a wavelength of 550nm of the high adhesion region is smaller than the visible light transmittance at a wavelength of 550nm of the low adhesion region.
10. A method for manufacturing an intermediate laminate, comprising:
a step of preparing an adhesive sheet including a substrate and an adhesive layer disposed on one surface of the substrate and formed of an adhesive composition, the adhesive composition having a visible light transmittance at a wavelength of 550nm that can be reduced by an external stimulus, and the adhesive composition being capable of undergoing an irreversible state change between a state of high adhesive force and a state of low adhesive force by the external stimulus;
disposing an adherend on one surface of the pressure-sensitive adhesive sheet; and
and applying the external stimulus to a part of the adhesive layer, and forming a stimulus portion to which the external stimulus is applied and a non-stimulus portion to which the external stimulus is not applied in the adhesive layer, whereby one of the stimulus portion and the non-stimulus portion is a high-adhesion region having a high adhesive force and the other is a low-adhesion region having a low adhesive force, and the visible light transmittance at a wavelength of 550nm of the stimulus portion is made smaller than the visible light transmittance at a wavelength of 550nm of the non-stimulus portion.
11. The method for producing an intermediate laminate according to claim 10, wherein the adhesive layer is formed from a 1 st adhesive composition, the visible light transmittance at a wavelength of 550nm of the 1 st adhesive composition can be reduced by an external stimulus, and the 1 st adhesive composition can be irreversibly changed from a state of high adhesive force by the external stimulus to a state of low adhesive force,
the stimulation portion becomes the low-adhesion area,
the non-irritating portion becomes the high adhesion area.
12. The method for producing an intermediate laminate according to claim 10, wherein the adhesive layer is formed from a2 nd adhesive composition, the visible light transmittance at a wavelength of 550nm of the 2 nd adhesive composition can be reduced by an external stimulus, and the 2 nd adhesive composition can be irreversibly changed from a state of low adhesive force by the external stimulus to a state of high adhesive force,
the stimulation portion becomes the high adhesion area,
the non-irritating portion becomes the low adhesion area.
13. A method for manufacturing a product laminate, comprising: a step of preparing an intermediate laminate produced by the method for producing an intermediate laminate according to claim 10; and
and removing the low adhesion region in the adhesive layer.
CN202080044219.5A 2019-06-21 2020-06-11 Adhesive sheet, intermediate laminate, method for producing intermediate laminate, and method for producing product laminate Pending CN113993960A (en)

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Application publication date: 20220128