TWI907350B - Laminated body and reinforcing membrane - Google Patents

Abstract

The laminate 1 of the present invention includes a reinforcing film 4 and a flexible adherend 5 disposed on one side of the reinforcing film 4. The reinforcing film 4 includes a substrate 2 and an adhesive layer 3 disposed on one side of the substrate 2, comprising a high-adhesion component and a low-adhesion component. The reinforcing film 4 has a first reinforcing film portion 6 and a second reinforcing film portion 7 disposed at intervals from each other in the surface direction of the flexible adherend 5. In each of the adhesive layers 3 of the first reinforcing film portion 6 and the second reinforcing film portion 7, in the thickness direction, the high-adhesion component is concentrated at the interface between the flexible adherend 5 and the adhesive layer 3.

Description

Laminated structures and reinforcing membranes

This invention relates to a laminate and a reinforcing membrane.

It is known that by temporarily attaching an adhesive film to the surface of a device before assembling, processing, or transporting various devices such as electronic devices, the aim is to protect the surface or impart impact resistance.

As such an adhesive film, there is a known type of curable adhesive sheet that has weaker adhesion before heating or irradiation with ultraviolet light, and whose adhesion is enhanced by heating or irradiation with ultraviolet light (see, for example, Patent 1).

By leaving this adhesive film in a bonded state, a laminate with excellent reinforcing properties can be obtained.

[Previous Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Publication No. 2011-127054

[The problem that the invention aims to solve]

On the other hand, there is a situation where, in order to increase the freedom of component configuration, this adhesive film is attached to a soft substrate to create a laminate.

Furthermore, there exists a situation where, in order to bend this laminate, the adhesive membrane in the central part is removed (in other words, only two adhesive membranes remain at both ends in the direction of the soft adhered body).

Furthermore, there is a drawback: if the laminate is bent as described above, the two adhesive films are easily peeled off.

This invention provides a laminate formed by firmly bonding a reinforcing film and a soft adherend, and the reinforcing film used in the laminate. [Technical Means for Solving the Problem]

The present invention [1] is a laminate having a reinforcing film and a soft adherend disposed on one side of the reinforcing film. The reinforcing film has a substrate and an adhesive layer disposed on one side of the substrate, comprising a high adhesive component and a low adhesive component. The reinforcing film has a first reinforcing film portion and a second reinforcing film portion disposed apart from each other in the direction of the surface of the soft adherend. In each of the adhesive layers of the first reinforcing film portion and the second reinforcing film portion, in the thickness direction, the high adhesive component is concentrated at the interface between the soft adherend and the adhesive layer.

The present invention [2] includes the laminate described in [1] above, wherein in each of the adhesive layer of the first reinforcing film portion and the adhesive layer of the second reinforcing film portion, the high-adhesion component and the low-adhesion component are mixed and present on the side of the adhesive layer that is further from the interface in the thickness direction than the interface.

The present invention [3] includes the laminate described in [1] or [2] above, wherein the high-adhesion component is a cured polyfunctional (meth)acrylate and the low-adhesion component is an acrylic polymer.

The present invention [4] includes the laminate described in [1] or [2] above, wherein the high-adhesion component is an acrylic polymer and the low-adhesion component is a component containing organosiloxane.

The present invention [5] is a laminate having a reinforcing film and a soft adherend disposed on one side of the reinforcing film, wherein the reinforcing film has a substrate and an adhesive layer disposed on one side of the substrate and comprising a high adhesive component and a low adhesive component, the reinforcing film having a first reinforcing film portion and a second reinforcing film portion disposed apart from each other in the direction of the surface of the soft adherend, the adhesive layer having an adhesive force of 5 N/25 mm or more, and the adhesive layer having a thickness of 5 μm or more.

The present invention [6] is a reinforcing film used in a laminate, the laminate having a reinforcing film and a soft adherend disposed on one side of the reinforcing film, wherein the reinforcing film has a substrate and an adhesive layer disposed on one side of the substrate and comprising a high-adhesion component and a low-adhesion component, and the reinforcing film having a first reinforcing film portion and a second reinforcing film portion disposed at intervals from each other in the direction of the surface of the soft adherend. [Effects of the Invention]

The laminate system has a first reinforcing film portion and a second reinforcing film portion disposed on the surface of the soft adherend in a manner that leaves space between each other.

Therefore, the laminate can be bent between the first reinforcing membrane portion and the second reinforcing membrane portion.

Furthermore, in both the adhesive layer of the first reinforcing film and the adhesive layer of the second reinforcing film, in the thickness direction, the highly adhesive component is concentrated at the interface between the soft adherend and the adhesive layer.

Therefore, in the laminate, the adhesive layer and the soft adherend are firmly bonded, and even when the laminate is bent as described above, the separation of the first reinforcing film and the second reinforcing film can be suppressed.

The embodiment of the laminate of the present invention will be described with reference to Figure 1.

1. Laminate As shown in Figure 1, the laminate 1 has: a reinforcing film 4 having a substrate 2 and an adhesive layer 3 disposed on one side of the substrate 2; and a soft adherend 5 disposed on one side of the reinforcing film 4.

Details will be described below, but the laminate 1 is obtained by attaching the reinforcing film 4 to the soft adherend 5.

The following is a detailed description of each layer.

2. Reinforcing film The reinforcing film 4 consists of a first reinforcing film portion 6 and a second reinforcing film portion 7 arranged with a gap between each other in the direction of the surface of the soft adherend 5.

The first reinforcing membrane portion 6 and the second reinforcing membrane portion 7 have a membrane shape (including a sheet shape) with a specific thickness, extend in a direction orthogonal to the thickness direction (surface direction), and have a flat upper surface and a flat lower surface.

Furthermore, the first reinforcing film portion 6 and the second reinforcing film portion 7 each have a substrate 2 and an adhesive layer 3 disposed on one side of the substrate 2.

That is, the reinforcing film 4 has a substrate 2 and an adhesive layer 3 disposed on one side of the substrate 2.

2-1. Substrate Substrate 2 is a support layer (support material) that ensures the mechanical strength of the reinforcing film 4. Furthermore, substrate 2 is a reinforcing material in the laminate 1 used to reinforce the soft adherend 5. Also, substrate 2 has a film shape extending in the surface direction, and has a flat plane and a flat lower surface.

Substrate 2 contains a flexible plastic 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 polymers (COP); polycarbonate resins; polyether resins; polyarylate resins; melamine resins; polyamide resins; polyimide resins; cellulose resins; polystyrene resins; and synthetic resins such as terpene resins.

Details will be described later, but when the adhesive layer 3 is hardened by light shining from the side of the substrate 2, it is preferable that the substrate 2 is transparent to light.

From the perspective of combining transparency to light and mechanical strength, polyester resin and polyethylene terephthalate (PET) are better examples of plastic materials.

The thickness of the substrate 2 is, for example, 4 μm or more. From the viewpoint of reinforcing the soft adhesive 5 (described later), it is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 45 μm or more. Alternatively, it may be 500 μm or less. From the viewpoint of flexibility and handleability, it is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less.

2-2. Adhesive layer 3 is disposed on the entire surface of one side of the substrate 2.

The adhesive layer 3 is a pressure-sensitive bonding layer used to attach the reinforcing film 4 to the soft adherend 5. Furthermore, the adhesive layer 3 has a film shape extending in the surface direction and has a flat plane and a flat lower surface.

The adhesive layer 3 is formed of an adhesive composition.

Adhesive compositions are compositions that can irreversibly change state from a state with lower adhesive strength to a state with higher adhesive strength.

Examples of such adhesive compositions include: a first adhesive composition that can irreversibly change state from a state of low self-adhesion to a state of high self-adhesion by means of light irradiation; and a second adhesive composition that can irreversibly change state from a state of low self-adhesion to a state of high self-adhesion by means of heating.

The first adhesive composition comprises a base polymer, a photocuring agent, and a photopolymerization initiator.

Examples of basic polymers include: acrylic polymers, natural rubber, styrene-isoprene-styrene block copolymers (SIS block copolymers), styrene-butadiene-styrene block copolymers (SBS block copolymers), styrene-ethylene-butene-styrene block copolymers (SEBS block copolymers), styrene-butadiene rubber, polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber, silicone rubber, etc. From the perspective of controlling adhesion, acrylic polymers are preferred.

Acrylic polymers are obtained by polymerizing a first monomer component containing alkyl (meth)acrylate as the main component.

Alkyl methacrylates are acrylates and/or methacrylates, such as: methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, dibutyl methacrylate, terbutyl methacrylate, amyl methacrylate, isoamyl methacrylate, neopentyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isooctyl methacrylate, propylene methacrylate Nonyl acrylate, isononyl acrylate, decyl acrylate, isodecanyl acrylate, undecyl acrylate, dodecyl acrylate, tri(dodecyl) acrylate, tetradecyl acrylate, isotetradecyl acrylate, pentadecyl acrylate, succinate acrylate, heptadecanyl acrylate, octadecyl acrylate, isooctadecyl acrylate, nonadecanyl acrylate, eicosyl acrylate, etc., in straight-chain or branched form, of C1-20 alkyl acrylates.

Alkyl methacrylates can be used alone or in combination of two or more.

As an alkyl methacrylate, from the viewpoint of adjusting the glass transition temperature and shear storage modulus G', the combined use of methyl methacrylate and C4-12 alkyl acrylate is preferable.

When methyl methacrylate and C4-12 alkyl acrylate are used together as (meth)acrylate alkyl esters, the blending ratio of methyl methacrylate is, for example, 5 parts by mass or more, or, for example, 20 parts by mass or less, relative to 100 parts by mass of the total amount of methyl methacrylate and C4-12 alkyl acrylate, and the blending ratio of C4-12 alkyl acrylate is, for example, 80 parts by mass or more, or, for example, 95 parts by mass or less.

The blending ratio of (meth)acrylate alkyl ester relative to the first monomer component is, for example, 50% by mass or more, preferably 60% by mass or more, or, for example, 80% by mass or less.

Furthermore, the first monomer component is preferably a vinyl monomer containing a functional group that can copolymerize with alkyl (meth)acrylates.

Examples of vinyl monomers containing functional groups include: vinyl monomers containing hydroxyl groups, vinyl monomers containing carboxyl groups, vinyl monomers containing nitrogen, vinyl monomers containing cyano groups, vinyl monomers containing glycidyl groups, vinyl monomers containing sulfonyl groups, vinyl monomers containing phosphate groups, aromatic vinyl monomers, vinyl ester monomers, vinyl ether monomers, etc.

Examples of vinyl monomers containing hydroxyl groups include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl methacrylate, 10-hydroxydecyl methacrylate, 12-hydroxylauryl methacrylate, and 4-(hydroxymethyl)cyclohexyl methacrylate. 2-hydroxyethyl methacrylate is a preferred example, and 2-hydroxyethyl acrylate is even more preferred.

Examples of vinyl monomers containing carboxyl groups include: (meth)acrylic acid, 2-carboxyethyl (meth)acrylic acid, carboxypentyl (meth)acrylic acid carboxypentyl ester, itaconic acid, maleic acid, fumaric acid, butenoic acid, etc.

Furthermore, examples of vinyl monomers containing carboxyl groups include maleic anhydride and isocarboxylic anhydride.

Examples of nitrogen-containing vinyl monomers include: N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperidine, vinylpyridine, vinylpyrrole, vinylimidazolium, vinylpyrazole, vinylpyridine, N-acrylamide, N-vinylcarboxylate, N-vinylcaprolactam, etc.

Examples of vinyl monomers containing cyano groups include (meth)acrylonitrile.

Examples of vinyl monomers containing glycidyl groups include glycidyl (meth)acrylate.

Examples of vinyl monomers containing sulfonyl groups include styrene sulfonic acid and allyl sulfonic acid.

Examples of vinyl monomers containing phosphate groups include 2-hydroxyethyl acrylate.

Examples of aromatic vinyl monomers include styrene, p-methylstyrene, ortho-methylstyrene, α-methylstyrene, etc.

Examples of vinyl ester monomers include vinyl acetate and vinyl propionate.

Examples of vinyl ether monomers include methyl vinyl ether.

As functionalized vinyl monomers, two or more can be used alone or in combination. In the case of formulating crosslinking agents (described below), from the viewpoint of introducing crosslinking structures into acrylic polymers, vinyl monomers containing hydroxyl groups and vinyl monomers containing carboxyl groups are preferred examples. Furthermore, from the viewpoint of improving cohesiveness, vinyl monomers containing nitrogen are preferred examples. More preferably, vinyl monomers containing hydroxyl groups and/or vinyl monomers containing carboxyl groups, and vinyl monomers containing nitrogen are used in combination.

When hydroxyl-containing vinyl monomers and/or carboxyl-containing vinyl monomers are used together with nitrogen-containing vinyl monomers, the blending ratio of hydroxyl-containing vinyl monomers and/or carboxyl-containing vinyl monomers to 100 parts by mass of the total amount of nitrogen-containing vinyl monomers and/or nitrogen-containing vinyl monomers is, for example, 40 parts by mass or more, or, for example, 60 parts by mass or less, and the blending ratio of nitrogen-containing vinyl monomers is, for example, 40 parts by mass or more, or, for example, 60 parts by mass or less.

The proportion of the functionalized vinyl monomer relative to the first monomer component is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, or, for example, 30% by mass or less, preferably 20% by mass or less.

Furthermore, the acrylic polymer is a polymer formed by polymerizing the first monomer component mentioned above.

When polymerizing the first monomer component, for example, by formulating alkyl methacrylates and, as needed, vinyl monomers containing functional groups to prepare the first monomer component, the first monomer component is prepared by known polymerization methods such as solution polymerization, block polymerization, emulsion polymerization, etc.

Solution polymerization is a preferred example of a polymerization method.

In solution polymerization, for example, a monomer solution is prepared by adding a first monomer component and a polymerization initiator to a solvent, and then the monomer solution is heated.

As a solvent, examples include organic solvents.

Examples of organic solvents 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. Ester solvents are preferred, and ethyl acetate is even more preferred.

Solvents can be used alone or in combination of two or more.

The solvent mixing ratio is 100 parts by mass relative to the first monomer component, for example, 100 parts by mass or more, preferably 200 parts by mass or more, or for example, 500 parts by mass or less, preferably 300 parts by mass or less.

Examples of polymerization initiators include peroxide-based polymerization initiators and azo-based polymerization initiators.

Examples of peroxide-based polymerization initiators include: peroxy carbonates, peroxide ketones, peroxy ketones, hydrogen peroxide, dialkyl peroxides, diacetyl peroxides, peroxy esters, and other organic peroxides.

Examples of azo compounds that can be used as initiators for azo polymerization include: 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), and dimethyl 2,2'-azobisisobutyrate.

As a polymerization initiator, azo polymerization initiators are preferred, and 2,2'-azobisisobutyronitrile is even more preferred.

Polymerization initiators can be used alone or in combination of two or more.

The mixing ratio of the polymerization initiator relative to 100 parts by mass of the first monomer component is, for example, 0.05 parts by mass or more, preferably 0.1 parts by mass or more, or, for example, 1 part by mass or less, preferably 0.5 parts by mass or less.

The heating temperature is, for example, above 50°C and below 80°C, and the heating time is, for example, above 1 hour and below 8 hours.

In this way, the first 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% by mass or more, or, for example, 80% by mass or less.

The weight average molecular weight of the acrylic polymer is, for example, 100,000 or more, preferably 300,000 or more, 500,000 or more, or, for example, less than 5,000,000, preferably less than 3,000,000, and even more preferably less than 2,000,000.

Furthermore, the aforementioned weight-average molecular weight was determined by GPC (gel permeation chromatography) and calculated using polystyrene conversion.

In the first adhesive composition, the glass transition temperature (Tg) of the base polymer is, for example, above -100°C, preferably above -80°C, more preferably above -40°C, and also, for example, below -10°C, preferably below -5°C, more preferably below 0°C.

This configuration is suitable in terms of ensuring the fluidity of the base polymer in the first adhesive composition, and therefore suitable in terms of changing the first adhesive composition to a high adhesive state by means of active energy lines (described below).

Furthermore, the glass transition temperature is a value recorded in literature or catalogues, or a value calculated based on the following formula (1) (Fox formula). The same applies to the glass transition temperatures of the other polymers described below.

1/Tg＝W ₁ /Tg ₁ +W ₂ /Tg ₂ +…+W _n /Tg _n (1)

In the above formula (1), Tg represents the glass transition temperature of polymer (A) (unit: K), Tg _i (i = 1, 2, ... n) represents the glass transition temperature of monomer i when it forms a homopolymer (unit: K), and _Wi (i = 1, 2, ... n) represents the mass fraction of monomer i in all monomer components.

In the first adhesive composition, the formulation ratio of the base polymer relative to the total amount of the base polymer, photocuring agent and photopolymerization initiator is, for example, 70% by mass or more, or, for example, 95% by mass or less.

From the perspective of light curing agents, which significantly enhance the adhesive strength of adhesive layer 3 through light irradiation, examples include multifunctional (meth)acrylates with a functional group number of 2 to 3. Specifically, examples include 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, and alkyldiol di(meth)acrylate. Difunctional (meth) acrylates include methacrylates such as tricyclodecanediethanol di(meth)acrylate, pentaerythritol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and glycerol di(meth)acrylate; and trifunctional (meth) acrylates such as ethoxyisocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and trihydroxymethylpropane tri(meth)acrylate, with difunctional (meth) acrylates being preferred.

Furthermore, examples of photocuring agents include: acrylic photoreactive oligomers, carbamate-based, polyether-based, polyester-based, polycarbonate-based, and polybutadiene-based photoreactive oligomers.

Light curing agents can be used alone or in combination of two or more.

Furthermore, the functional group equivalent of the photocuring agent is, for example, 50 g/eq or more, or, for example, 500 g/eq or less.

The viscosity of the light-curing agent at 25°C is, for example, 5 mPa·s or more, or, for example, 1000 mPa·s or less.

From the perspective of compatibility, the molecular weight of the photocuring agent is, for example, less than 200, or more than 1000.

Furthermore, the light curing agent is preferably one that is incompatible with the base polymer (preferably an acrylic polymer).

If the light-curing agent is not compatible with the base polymer (preferably an acrylic polymer), the adhesion of the adhesive layer 3 that has not been exposed to light (described below) may be reduced.

The mixing ratio of the light curing agent relative to 100 parts by mass of the base polymer is, for example, 10 parts by mass or more, or, for example, 50 parts by mass or less, preferably 30 parts by mass or less.

Furthermore, the mixing ratio of the photocuring agent relative to the total amount of the base polymer, photocuring agent, and photopolymerization initiator is, for example, 5% by mass or more, or, for example, 30% by mass or less.

Photopolymerization initiators promote the curing reaction of photocuring agents, and can be appropriately selected according to the type of photocuring agent. Examples include: photocationic initiators (photoacid generators), hydroxy ketones such as 1-hydroxycyclohexylphenyl ketone, benzohexanedimethyl acetones, amino ketones, acetophosphine oxides, benzophenones, photoradical initiators such as trichloromethyl triazine derivatives, and photocationic initiators (photoalkali generators).

Photopolymerization initiators can be used alone or in combination of two or more.

In the case of using polyfunctional (meth)acrylates as photocuring agents, photoradical initiators are preferred, and hydroxyl ketones are even more preferred.

The light absorption region of the photopolymerization initiator is, for example, above 300 nm, or below 450 nm.

The ratio of the photopolymerization initiator to the base polymer is, for example, more than 0.01 parts by mass, or, for example, less than 1 part by mass, preferably less than 0.5 parts by mass.

Furthermore, the proportion of the photopolymerization initiator relative to the total amount of the base polymer, photocuring agent, and photopolymerization initiator is, for example, 0.01% by mass or more, or, for example, 1% by mass or less, preferably 0.5% by mass or less.

Furthermore, in preparing the first adhesive composition, the base polymer (preferably an acrylic polymer (in the case of preparing an acrylic polymer by solution polymerization, an acrylic polymer solution)), the photocuring agent, and the photopolymerization initiator are formulated and mixed in the above ratio.

In the first adhesive composition, from the viewpoint of introducing a crosslinking structure into the base polymer (preferably an acrylic polymer), a formulation crosslinking agent is preferred.

Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, and metal chelate-based crosslinking agents, with isocyanate-based crosslinking agents being a preferred example.

Examples of isocyanate crosslinking agents include: aliphatic diisocyanates such as butyl diisocyanate and hexamethylene diisocyanate; alicyclic diisocyanates such as cyclopentyl diisocyanate, cyclohexyl diisocyanate, and isophorone diisocyanate; and aromatic diisocyanates such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and phenyl dimethyl diisocyanate.

Furthermore, as isocyanate-based crosslinking agents, derivatives of the aforementioned isocyanates (such as isocyanurate modifiers, polyol modifiers, etc.) can also be cited.

As an isocyanate crosslinking agent, commercially available products can also be used, such as: Coronate L (trihydroxymethylpropane adduct of toluene diisocyanate, manufactured by Tosoh), Coronate HL (trihydroxymethylpropane adduct of hexamethylene diisocyanate, manufactured by Tosoh), Coronate HX (isocyanurate form of hexamethylene diisocyanate), Takenate D110N (trihydroxymethylpropane adduct of phenyl diisocyanate, manufactured by Mitsui Chemicals), etc.

Crosslinking agents can be used alone or in combination of two or more.

If a crosslinking agent is incorporated into the first adhesive composition, the hydroxyl and other functional groups in the base polymer (preferably an acrylic polymer) react with the crosslinking agent to introduce a crosslinked structure into the base polymer (preferably an acrylic polymer).

The functional group equivalent of the crosslinking agent is, for example, 50 g/eq or more, or, for example, 500 g/eq or less.

The mixing ratio of the crosslinking agent relative to 100 parts by weight of the base polymer is, for example, 0.1 parts by weight or more, preferably 1.0 parts by weight or more, more preferably 1.5 parts by weight or more, and even more preferably 2.0 parts by weight or more, or, for example, 10 parts by weight or less, preferably 5 parts by weight or less, and even more preferably 4 parts by weight or less.

Furthermore, when a crosslinking agent is formulated into the first adhesive composition, a crosslinking catalyst may also be formulated to promote the crosslinking reaction.

Examples of crosslinking catalysts include: tetrabutyl titanium ester, tetraisopropyl titanium ester, iron triacetone, butyltin oxide, dioctyltin dilaurate, and other metal-based crosslinking catalysts.

Cross-linked catalysts can be used alone or in combination of two or more.

The mixing ratio of the crosslinked catalyst relative to 100 parts by mass of the base polymer 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.

Furthermore, the first adhesive composition may contain, as needed and to the extent that it does not impair the effects of the invention, various additives such as silane coupling agents, adhesive enhancers, plasticizers, softeners, anti-deterioration agents, fillers, colorants, UV absorbers that stabilize under fluorescent or natural light, antioxidants that stabilize under fluorescent or natural light, surfactants, antistatic agents, etc.

In this way, the first adhesive composition is obtained.

The formulation ratio of the base polymer relative to the first adhesive component is, for example, 50% by mass or more, preferably 80% by mass or more, or, for example, 90% by mass or less.

The mixing ratio of the light curing agent relative to the first adhesive component is, for example, 10% by mass or more, or, for example, 50% by mass or less.

The proportion of the photopolymerization initiator relative to the first adhesive component is, for example, 0.01% by mass or more, or, for example, 0.5% by mass or less, preferably 0.1% by mass or less.

The second adhesive composition comprises the aforementioned base polymer and an organosiloxane-containing component.

As a basic polymer, acrylic polymers are a good example.

In the second adhesive composition, the glass transition temperature (Tg) of the base polymer is, for example, above -100°C, preferably above -80°C, more preferably above -40°C, and also, for example, below -10°C, preferably below -5°C, more preferably below 0°C.

This configuration is suitable in terms of ensuring the flowability of the base polymer in the second adhesive composition, and therefore suitable in terms of changing the second adhesive composition to a high adhesive state by heating.

The base polymer can be used alone or in combination of two or more.

The blending ratio of the base polymer relative to the total amount of the base polymer and the component containing organosilicon is, for example, 70% by mass or more, or, for example, 99% by mass or less, preferably 90% by mass or less.

As a component containing organosiloxanes, examples include acrylic polymers, urethane polymers, polyether polymers, polyester polymers, polycarbonate polymers, and polybutadiene polymers that have organosiloxane backbones. From the viewpoint of controlling adhesive strength, acrylic polymers with organosiloxane backbones are preferred.

Acrylic polymers having an organosiloxane backbone are obtained by polymerization of a second monomer component comprising a monomer having an organosiloxane backbone and the aforementioned (meth)acrylate alkyl ester.

There are no particular limitations on the monomer having an organosiloxane skeleton; any monomer containing an organosiloxane skeleton can be used.

As a monomer having an organosilicon skeleton, for example, a compound represented by the following general formula (1) or (2) can be used.

[Chemistry 1]

In the above formula (1), ^R1 represents hydrogen or methyl, and m represents an integer greater than or equal to 0.

[Chemistry 2]

In the above formula (2), ^R1 and m have the same meaning as ^R1 and m in the above formula (1), ^R2 represents a methyl group or a monovalent organic group, and n represents an integer greater than 0.

Furthermore, as a monomer with an organosilicon skeleton, commercially available products can also be used. Specifically, examples include X-22-174ASX, X-22-2426, X-22-2475, and KF-2012 (the above are single-terminal reactive silicones manufactured by Shin-Etsu Chemical Industry Co., Ltd.).

The functional group equivalent of the monomer having an organosilicon skeleton is, for example, 700 g/mol or more, preferably 800 g/mol or more, more preferably 850 g/mol or more, and even more preferably 1500 g/mol or more; and, for example, less than 20000 g/mol, preferably less than 15000 g/mol, more preferably less than 10000 g/mol, even more preferably less than 6000 g/mol, and even more preferably less than 5000 g/mol.

The proportion of the monomer having an organosiloxane backbone relative to the total amount of the monomer having an organosiloxane backbone and the (meth)acrylate alkyl ester is, for example, 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, and, for example, 60% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

Furthermore, the second monomer component may preferably also include the aforementioned vinyl monomers containing functional groups.

Furthermore, the acrylic polymer having an organosilicon backbone is a polymer formed by polymerizing the aforementioned second monomer component.

When polymerizing the second monomer component, for example, a monomer having an organosiloxane backbone is formulated with an alkyl methacrylate and a vinyl monomer containing a functional group is formulated as needed to prepare the second monomer component, which is prepared by known polymerization methods such as solution polymerization, block polymerization, emulsion polymerization, etc.

Solution polymerization is a preferred example of a polymerization method.

In solution polymerization, for example, a monomer solution is prepared by adding a second monomer component and the above-mentioned polymerization initiator to a solvent, and then the monomer solution is heated.

Furthermore, in the above polymerization, known chain transfer agents can be used to adjust the molecular weight.

In this way, an acrylic polymer with an organosiloxane backbone was obtained.

This type of acrylic polymer with an organosiloxane backbone has an organosiloxane backbone on its side chains. Therefore, due to the mobility and ease of movement of the side chains, the acrylic polymer with this organosiloxane backbone has a lower initial adhesion (adhesion before heating), and the adhesion increases with heating.

Furthermore, the second adhesive composition is obtained by mixing a base polymer and an organosiloxane-containing component.

Furthermore, the aforementioned crosslinking agent and crosslinking catalyst may also be incorporated into the second adhesive composition.

Furthermore, the second adhesive composition may contain, as needed and to the extent that it does not impair the effects of the invention, various additives such as silane coupling agents, adhesive enhancers, plasticizers, softeners, anti-deterioration agents, fillers, colorants, UV absorbers that stabilize under fluorescent or natural light, antioxidants that stabilize under fluorescent or natural light, surfactants, antistatic agents, etc.

In this way, a second adhesive composition is obtained.

In the second adhesive composition, the proportion of the organosiloxane component relative to 100 parts by weight of the base polymer is, for example, 0.1 parts by weight or more, preferably 0.3 parts by weight or more, more preferably 0.4 parts by weight or more, even more preferably 0.5 parts by weight or more, particularly preferably 1 part by weight or more, most preferably 2 parts by weight or more, and, for example, 75 parts by weight or less, preferably 50 parts by weight or less, more preferably 20 parts by weight or less, even more preferably 10 parts by weight or less, particularly preferably 8 parts by weight or less, most preferably 5 parts by weight or less.

Furthermore, an adhesive layer 3 is formed by the self-adhesive composition (first adhesive composition or second adhesive composition) using the following method.

From the perspective of adhesion, the thickness of the adhesive layer 3 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. From the perspective of efficiency, it is, for example, 300 μm or less, preferably 100 μm or less, more preferably 50 μm or less, even more preferably 40 μm or less, and even more preferably 30 μm or less.

2-3. Method for manufacturing the reinforcing membrane Next, the method for manufacturing the reinforcing membrane 4 will be explained with reference to Figure 2.

The method for manufacturing the reinforcing film 4 includes: a first step of preparing a substrate 2, and a second step of applying an adhesive layer 3 to one side of the substrate 2.

In step 1, as shown in Figure 2A, substrate 2 is prepared.

In step 2, as shown in Figure 2B, an adhesive layer 3 is disposed on one side of the substrate 2.

When the adhesive layer 3 is applied to one side of the substrate 2, for example, the adhesive composition is applied to one side of the substrate 2, and the solvent is dried and removed as needed.

Examples of coating methods for adhesive compositions include: roller coating, contact roller coating, gravure coating, reverse coating, roller brush coating, spraying, dip roller coating, rod coating, scraping, air knife coating, curtain coating, mold lip coating, and mold nozzle coating.

As for drying conditions, the drying temperature is, for example, above 50°C, preferably above 70°C, more preferably above 100°C, or, for example, below 200°C, preferably below 180°C, more preferably below 150°C, and the drying time is, for example, above 5 seconds, preferably above 10 seconds, or, for example, below 20 minutes, preferably below 15 minutes, more preferably below 10 minutes.

In this way, an adhesive layer 3 is formed on one side of the substrate 2, thereby obtaining a reinforcing film 4 having the substrate 2 and the adhesive layer 3 disposed on one side of the substrate 2.

Furthermore, when the adhesive composition contains a crosslinking agent, crosslinking is preferably carried out by aging, either simultaneously with drying or after the solvent has dried (after peeling off the film 8 on one area of the adhesive layer 3 (described below)).

The aging conditions are set appropriately according to the type of crosslinking agent. For example, the aging temperature is above 20°C, or below 160°C, preferably below 100°C. The aging time is above 1 minute, preferably above 12 hours, more preferably above 1 day, or below 7 days.

Furthermore, as shown in Figure 2C, the reinforcing membrane 4 can also be peeled off as needed onto one area of the adhesive layer 3.

In this case, the reinforcing membrane 4 sequentially comprises a substrate 2, an adhesive layer 3, and a peeling membrane 8.

As a release film 8, examples of flexible plastic films include polyethylene, polypropylene, polyethylene terephthalate, and polyester film.

The thickness of the exfoliating membrane 8 is, for example, 3 μm or more, preferably 10 μm or more, and also, for example, 200 μm or less, preferably 100 μm or less, and more preferably 50 μm or less.

For the release film 8, it is preferable to use release agents such as silicone-based, fluorine-based, long-chain alkyl-based, or fatty acid amide-based release agents for release treatment, or to use silica powder for release treatment.

3. Flexible Adhesive The flexible adhesive 5 is a flexible, reinforced body reinforced by the reinforcing film 4. Examples include flexible optical devices such as flexible display panels, flexible electronic devices such as flexible printed circuit boards (FPCs), and flexible substrates that serve as components of such devices. When the flexible adhesive 5 is a flexible optical device, a pixel region containing a plurality of pixels arranged in an array, a circuit region containing various circuit elements such as driver circuits, and a wiring pattern connecting such electrical components are formed on one side of the flexible adhesive 5. When the flexible substrate 5 is a flexible electronic device, various circuit components and wiring patterns are formed on one side of the flexible substrate 5. In Figure 1, the flexible substrate 5 has a flat plate shape, but various top-view shapes can be obtained according to the design of the target device.

4. Manufacturing method of laminate 1 Referring to Figure 3, one embodiment of the manufacturing method of laminate 1 will be explained.

The manufacturing method of the laminate 1 includes: a step of preparing a reinforcing film 4 (step 3); a step of placing a soft adhesive 5 on one side of the reinforcing film 4 (step 4); a step of forming a first reinforcing film portion 6 and a second reinforcing film portion 7 by removing a portion of the reinforcing film 4 (step 5); and a step of increasing the adhesive force of the adhesive layer 3 (step 6).

As described above, the common feature of the first adhesive composition and the second adhesive composition is that they are compositions capable of irreversibly changing from a state with lower adhesive strength to a state with higher adhesive strength. However, they differ in the following aspects: the first adhesive composition changes state by light, while the second adhesive composition changes state by heat.

Furthermore, details will be described later, but in the first adhesive composition, the cured product of the photocuring agent (preferably a polyfunctional (meth)acrylate) becomes a high-adhesion component with relatively high adhesive strength, and the base polymer (preferably an acrylic polymer) becomes a low-adhesion component with relatively low adhesive strength. On the other hand, in the second adhesive composition, the base polymer (preferably an acrylic polymer) becomes a high-adhesion component with relatively high adhesive strength, and the component containing organosiloxane (preferably an acrylic polymer with an organosiloxane backbone) becomes a low-adhesion component with relatively low adhesive strength. That is, the high-adhesion component and the low-adhesion component in the adhesive layer 3 are determined according to whether the adhesive layer 3 is formed by the first adhesive composition or the second adhesive composition.

Therefore, the following explanation will be divided into the case where the adhesive layer 3 is formed by the first adhesive composition and the case where the adhesive layer 3 is formed by the second adhesive composition.

4-1. Method for manufacturing a laminate containing an adhesive layer formed by a first adhesive composition First, a method for manufacturing a laminate containing an adhesive layer 3 formed by a first adhesive composition (method 1) will be explained with reference to FIG3.

In step 3, as shown in Figure 3A, the reinforcing membrane 4 is prepared.

Next, in step 4, as shown in Figure 3B, the reinforcing film 4 is bonded to the soft substrate 5 in such a way that the adhesive layer 3 disposed on one side of the substrate 2 is in contact with the soft substrate 5.

At this time, at the interface between the adhesive layer 3 and the soft adherend 5, the photocuring agent (preferably a multifunctional (meth)acrylate) is segregated.

Furthermore, this light-curing agent hinders the adhesion between the adhesive layer 3 and the soft adherend 5.

Therefore, the adhesive force of the adhesive layer 3 to the soft adherend 5 can be reduced. Specifically, the adhesive force of the adhesive layer 3 is, for example, 4 N/25 mm or less, preferably 1 N/25 mm or less.

If the adhesive force of the adhesive layer 3 is below the upper limit mentioned above, then a portion of the reinforcing film 4 can be easily removed in step 5 below.

Furthermore, the aforementioned adhesion was determined by bonding the reinforcing film 4 to the polyimide film at 25°C and performing a 180-degree peel test at a peeling speed of 300 mm/min.

Then, in step 5, a portion of the reinforcing membrane 4 is removed.

Specifically, only one part of the central portion of the three parts that divide the reinforcing membrane 4 along the surface direction is removed (hereinafter referred to as the removed portion 9).

When removing a portion of the reinforcing film 4, firstly, as shown in Figure 3C, the portion to be removed 9 is cut off by laser light such as _CO2 laser or YAG laser, or by a knife such as a Thomson knife, Binok knife, rotary knife, scraper, or blade. Then, the portion to be removed 9 is peeled off only from the end of the portion to be removed 9.

Thus, as shown in Figure 3C, the first reinforcing membrane portion 6 and the second reinforcing membrane portion 7 remain.

Then, in step 6, the adhesive force of adhesive layer 3 is increased.

Specifically, the adhesive layer 3 of the first reinforcing film portion and the adhesive layer 3 of the second reinforcing film portion 7 are respectively irradiated with light. The light includes active energy lines such as ultraviolet rays and electron beams.

In this way, the photocuring agent (preferably a polyfunctional (meth)acrylate) that is segregated at the interface between the adhesive layer 3 and the soft adherend 5 is cured, and the adhesion of the cured material becomes higher.

That is, in the first adhesive composition, the adhesive strength of the cured product of the photocuring agent (preferably a polyfunctional (meth)acrylate) is improved, while the adhesive strength of the base polymer (preferably an acrylic polymer) is not improved.

Therefore, compared to the base polymer (preferably an acrylic polymer), the adhesive force of the cured product of the photocuring agent (preferably a polyfunctional (meth)acrylate) becomes relatively high. Thus, the cured product of the photocuring agent (preferably a polyfunctional (meth)acrylate) becomes a high-adhesion component, while the base polymer (preferably an acrylic polymer) becomes a low-adhesion component.

Furthermore, the cured material of the photocuring agent (preferably a multifunctional (meth)acrylate) which is a high-adhesion component exists in a segregated state at the interface between the adhesive layer 3 and the soft adherend 5.

Specifically, in the TOF-SIMS (Time of Flight Secondary Ion Mass Spectrometry) measurements described below, the ratio of high-adhesion components in the region starting from the interface between the adhesive layer 3 and the soft adherend 5 and ending at a depth equivalent to 5% of the thickness of the adhesive layer 3 from that interface toward the adhesive layer 3 is, for example, more than twice, preferably more than three times, the ratio of low-adhesion components.

In this way, the adhesive layer 3 and the soft adherend 5 can be firmly bonded together.

Specifically, the adhesive force of the adhesive layer 3 after light irradiation is, for example, 5 N/25 mm or more, preferably 8 N/25 mm or more, more preferably 10 N/25 mm or more, and even more preferably 12 N/25 mm or more.

On the other hand, a portion of the cured product of the photocuring agent (preferably a polyfunctional (meth)acrylate) is miscible with the base polymer (preferably an acrylic polymer) and diffuses from the interface between the adhesive layer 3 and the soft substrate 5 toward the adhesive layer 3. Thus, in the thickness direction, the cured product of the photocuring agent (preferably a polyfunctional (meth)acrylate) (high adhesive component) and the base polymer (preferably an acrylic polymer) (low adhesive component) are mixed and present on the adhesive layer 3 side, which is more prominent than the interface between the adhesive layer 3 and the soft substrate 5.

Specifically, in the TOF-SIMS measurement described below, the ratio of high-adhesion components in the region from the interface between the self-adhesive layer 3 and the soft adherend 5 toward the adhesive layer 3, at a depth equivalent to 30% of the thickness of the adhesive layer 3, and ending at a depth equivalent to 70% of the thickness of the adhesive layer 3, is, for example, at least 0.8 times, preferably at least 1 time, and, for example, at least 1.5 times, that of the low-adhesion components.

This improves shear creep properties.

Based on the above, layer 1 is obtained.

4-2. Method for manufacturing a laminate containing an adhesive layer formed by a second adhesive composition Second, with reference to FIG3, a method (manufacturing method 2) for manufacturing a laminate containing an adhesive layer 3 formed by a second adhesive composition will be described.

As described above, the second adhesive composition comprises a base polymer and an organosiloxane-containing component.

The following is a detailed description of the case where the base polymer is an acrylic polymer and the component containing organosiloxane is an acrylic polymer with an organosiloxane backbone.

In the second adhesive composition, the acrylic polymer exhibits relatively higher adhesive strength compared to the acrylic polymer with an organosilicon backbone. That is, in the second adhesive composition, the acrylic polymer is the high-adhesion component, while the acrylic polymer with an organosilicon backbone is the low-adhesion component.

In step 3, as shown in Figure 3A, the reinforcing membrane 4 is prepared.

Next, in step 4, as shown in Figure 3B, the reinforcing film 4 is bonded to the soft substrate 5 in such a way that the adhesive layer 3 disposed on one side of the substrate 2 is in contact with the soft substrate 5.

Here, at the interface between the adhesive layer 3 and the soft adherend 5, there is an agglomeration of acrylic polymers with an organosilicon backbone.

Furthermore, this acrylic polymer barrier layer 3 with an organosilicon backbone hinders the adhesion between the adhesive layer 3 and the soft adherend 5.

Therefore, the adhesive force of the adhesive layer 3 to the soft adherend 5 can be reduced. Specifically, the adhesive force of the adhesive layer 3 is, for example, 4 N/25 mm or less, preferably 1 N/25 mm or less.

If the adhesive force of the adhesive layer 3 is below the upper limit mentioned above, then a portion of the reinforcing film 4 can be easily removed in step 5 below.

Then, in step 5, as described above, a portion of the reinforcing membrane 4 is removed.

Thus, as shown in Figure 3C, the first reinforcing membrane portion 6 and the second reinforcing membrane portion 7 remain.

Then, in step 6, the adhesive force of adhesive layer 3 is increased.

Specifically, the adhesive layer 3 of the first reinforcing film portion and the adhesive layer 3 of the second reinforcing film portion 7 are heated respectively.

As for heating conditions, the heating temperature is, for example, above 40°C, preferably above 50°C, more preferably above 60°C, and also, for example, below 150°C, preferably below 120°C, more preferably below 100°C, and even more preferably below 80°C. The heating time is not particularly limited, for example, less than 1 hour, preferably less than 30 minutes, more preferably less than 10 minutes, and even more preferably less than 5 minutes, and also, for example, more than 1 minute. Furthermore, heating for a longer period (for example, more than 2 hours, preferably more than 5 hours) can be performed within the limit that the reinforcing film 4 or the adhered body 5 does not produce significant thermal degradation. Moreover, the above heating can be performed multiple times.

In this way, the compatibility between the acrylic polymer with an organosiloxane backbone, which is segregated at the interface between the adhesive layer 3 and the soft adherend 5, and the acrylic polymer with an organosiloxane backbone, is improved, and the acrylic polymer with an organosiloxane backbone is diffused to the adhesive layer 3 from the interface between the self-adhesive layer 3 and the soft adherend 5.

Thus, at the interface between the adhesive layer 3 and the soft adherend 5, the proportion of acrylic polymers that are clustered together is relatively higher (in other words, the acrylic polymers, as high adhesive components, are clustered together at the interface between the adhesive layer 3 and the soft adherend 5).

Specifically, in the TOF-SIMS measurement described below, the ratio of high-adhesion components in the region where the interface between the adhesive layer 3 and the soft adherend 5 is taken as the starting point and the depth from the interface towards the adhesive layer 3, which is equivalent to 5% of the thickness of the adhesive layer 3, is taken as the ending point, is, for example, more than twice, and preferably more than three times, the ratio of low-adhesion components.

In this way, the adhesive layer 3 and the soft adherend 5 can be firmly bonded together.

Specifically, the adhesive force of the adhesive layer 3 after heating is, for example, 5 N/25 mm or more, preferably 8 N/25 mm or more, more preferably 10 N/25 mm or more, and even more preferably 12 N/25 mm or more.

On the other hand, if the interface between the acrylic polymer self-adhesive layer 3 with an organosilicon backbone and the soft substrate 5 is diffused towards the adhesive layer 3, then in the thickness direction, the interface between the adhesive layer 3 and the soft substrate 5 is more on the adhesive layer 3 side, and the acrylic polymer (high adhesion component) and the acrylic polymer with an organosilicon backbone (low adhesion component) coexist in a mixture.

Specifically, in the TOF-SIMS measurement described below, the ratio of high-adhesion components in the region from the interface between the self-adhesive layer 3 and the soft adherend 5 toward the adhesive layer 3, at a depth equivalent to 30% of the thickness of the adhesive layer 3, and ending at a depth equivalent to 70% of the thickness of the adhesive layer 3, is, for example, at least 0.8 times, preferably at least 1 time, and, for example, at least 1.5 times, that of the low-adhesion components.

This improves shear creep properties.

Based on the above, layer 1 is obtained.

7. Effects of the laminate 1 In the laminate 1, a first reinforcing film 6 and a second reinforcing film 7 are arranged in a way that they are spaced apart from each other in the direction of the surface of the soft adhered body 5.

Therefore, as shown in Figure 4, the laminate 1 can be bent between the first reinforcing film 6 and the second reinforcing film 7 such that the first reinforcing film 6 and the second reinforcing film 7 face outwards from each other. Alternatively, the laminate 1 can be bent between the first reinforcing film 6 and the second reinforcing film 7 such that the first reinforcing film 6 and the second reinforcing film 7 face inwards from each other.

Furthermore, in both the adhesive layer 3 of the first reinforcing film portion 6 and the adhesive layer 3 of the second reinforcing film portion 7, in the thickness direction, the highly adhesive component is concentrated at the interface between the soft adherend 5 and the adhesive layer 3.

Therefore, in the laminate 1, the adhesive layer 3 and the soft adherend 5 are firmly bonded. In particular, even when the laminate 1 is bent with the first reinforcing film 6 and the second reinforcing film 7 facing outwards from each other, it can suppress peeling due to shear force from the reinforcing film 4 toward the central portion of the adhesive layer 3. Furthermore, even when the laminate 1 is bent with the first reinforcing film 6 and the second reinforcing film 7 facing inwards from each other, it can suppress peeling due to shear force from the central portion of the adhesive layer 3 toward the reinforcing film 4.

Furthermore, in the laminate 1, on the side of the adhesive layer 3 that is closer to the interface between the adhesive layer 3 and the soft adherend 5 in the thickness direction, high-adhesion components and low-adhesion components coexist in a mixture.

Therefore, even if the laminate 1 is subjected to bending stress as described above, the stress generated by bending is dispersed, and damage to the laminate 1 can be suppressed.

That is, the laminate 1 has excellent shear creep characteristics.

8. Variation Example In the above method for manufacturing a laminate in which an adhesive layer is formed from the second adhesive composition, an acrylic polymer having an organosiloxane backbone was used as a low-adhesion component, but it is not limited to this. For example, there may be a case where, by heating in step 6, the organosiloxane backbone, which serves as a side chain in the acrylic polymer having an organosiloxane backbone, moves molecularly from the interface between the adhesive layer 3 and the soft adherend 5 toward the adhesive layer 3. On the other hand, the main chain (acrylic backbone) continues to be segregated at the interface between the adhesive layer 3 and the soft adherend 5.

In this case, the side chains of acrylic polymers with organosilicon backbones become low-adhesion components, while the backbones of acrylic polymers with organosilicon backbones become high-adhesion components.

[Examples] The present invention will be further explained in detail below by showing examples and comparative examples. Furthermore, the present invention is not limited by any of the examples and comparative examples. Also, the specific numerical values such as blending ratios (including ratios), physical property values, and parameters used in the following description can be replaced by the corresponding upper limit values (defined as "below" or "not reaching") or lower limit values (defined as "above" or "exceeding") of the blending ratios (including ratios), physical property values, and parameters described in the above-mentioned "Examples".

Furthermore, unless otherwise specified, "parts" and "%" are considered quality standards.

1. Detailed List of Ingredients The ingredients used in each embodiment and comparative example are described below. Takenate D110N: 75% ethyl acetate solution of the trihydroxymethylpropane adduct of phenyl diisocyanate, Mitsui Chemicals, Ltd. APG700: Polypropylene glycol #700 (n=12) diacrylate; functional group equivalent 404 g/eq Irgacure 184: 1-Hydroxycyclohexylphenyl ketone, BASF, Ltd.

2. Preparation of Polymers Synthesis Example 1

A reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet pipe was added to a mixture of 9 parts by weight of methyl methacrylate (MMA) as monomers, 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 parts by weight of azobisisobutyronitrile (azobisisobutyronitrile) as a polymerization initiator, and 233 parts by weight of ethyl acetate as a solvent. Nitrogen gas was introduced, and the mixture was stirred while undergoing nitrogen replacement for approximately 1 hour. The mixture was then heated to 60°C and reacted for 7 hours to obtain a solution of an acrylic polymer with a weight average molecular weight (Mw) of 1,200,000.

3. Preparation of Adhesive Components Preparation Example 1 (Preparation of the First Adhesive Component)

Takenate D110N (75% ethyl acetate solution of trihydroxymethylpropane adduct of diphenyl diisocyanate, manufactured by Mitsui Chemicals) was added as a crosslinking agent to the acrylic polymer solution of Synthesis Example 1, with an amount of 2.5 parts by weight relative to 100 parts by weight of the polymer solids. APG700 (polypropylene glycol #700 (n=12) diacrylate) was added as a photocuring agent, with an amount of 20 parts by weight relative to 100 parts by weight of the polymer solids. Irgacure 184 (1-hydroxycyclohexylphenyl ketone, manufactured by BASF) was added as a photopolymerization initiator, with an amount of 0.1 parts by weight relative to 100 parts by weight of the polymer solids. The mixture was then homogeneously mixed to prepare the first adhesive composition.

4. Manufacturing of Reinforcing Membrane Manufacturing Example 1

A 75 μm thick polyethylene terephthalate film (Toray's "Lumirror S10") without surface treatment was used as a substrate. The photocurable composition of Preparation Example 1 was coated onto this substrate to a dry thickness of 25 μm using a roller. The solvent was removed by drying at 130°C for 1 minute. This formed an adhesive layer on one side of the substrate. Then, the release film (a 25 μm thick polyethylene terephthalate film with a silicone release treatment) was laminated onto the release surface of the adhesive layer. Finally, an aging treatment was performed at 25°C for 4 days to allow the crosslinking reaction between the polymer and the crosslinking agent to proceed. This produced a reinforcing film.

5. Manufacturing of Laminated Materials Example 1

After the release membrane is peeled off from the reinforcing membrane of Manufacturing Example 1, the reinforcing membrane is attached to a 12.5 μm thick polyimide membrane ("Kapton 50EN" manufactured by Toray DuPont).

Next, laser light is used to divide the reinforcing film into three parts along the surface direction, and one part of the central part is peeled off.

In this way, two parts (i.e., the first reinforcing membrane part and the second reinforcing membrane part) of the two ends of the three parts that are divided along the surface direction of the reinforcing membrane are retained.

Then, light is irradiated onto the adhesive layer in the first reinforcing film and the adhesive layer in the second reinforcing film to increase the adhesive force of the adhesive layer.

This is used to create laminates.

6. Evaluation (Distribution of high-adhesion and low-adhesion components in the adhesive layer) (TOF-SIMS determination)

For the laminate of Example 1, the distribution of high-adhesion and low-adhesion components in the adhesive layer was determined using TOF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry, TRIFT V nano TOF) with an Ar-GCIB (Ar Gas Cluster Ion Beam) gun manufactured by ULVAC-PHI. _Bi³⁺ ⁽ 30 kV) was used as the primary ion source. A 25 eV electron gun was used during charge neutralization. Ar-GCIB (Ar2500 ⁺ , 20 kV) was used for depth-direction resolution.

The results are shown in Table 1.

7. Discussion As shown in Table 1, at a penetration depth of 0 nm from the adhesive layer, the peak intensity (a.u.) of the cured material of the photocuring agent is 0.13. This indicates that the cured material (high-adhesion component) of the photocuring agent is segregated at the interface between the polyimide film and the adhesive layer.

Furthermore, at a penetration depth of 500 nm from the adhesive layer, the peak strength (a.u.) of both the cured material of the photocuring agent and the acrylic polymer is 0.025.

Therefore, it can be seen that at the interface between the polyimide film and the adhesive layer, on the adhesive layer side, the cured product of the light-curing agent (high adhesive component) and the acrylic polymer (low adhesive component) are mixed together.

[Table 1] Implementation Example No. Hardened material of light hardener acrylic polymers Penetration depth (nm) Peak intensity (au) Penetration depth (nm) Peak intensity (au) Implementation Example 1 0 0.13 0 0.02 500 0.025 500 0.025 1200 0.034 1200 0.023

Furthermore, the above-described invention is provided as an illustrative embodiment of the present invention, but it is merely an example and should not be interpreted restrictively. Variations of the present invention known to those skilled in the art are included within the scope of the following invention claim. [Industrial Applicability]

The laminate and reinforcing film of this invention are suitable for use in optical devices, electronic devices and their constituent parts.

1: Laminate 2: Substrate 3: Adhesive layer 4: Reinforcing film 5: Flexible adherend 6: First reinforcing film portion 7: Second reinforcing film portion 9: Removed portion

Figure 1 is a schematic diagram of one embodiment of the laminate of the present invention. Figure 2 is a schematic diagram of one embodiment of the manufacturing method of the reinforcing film, where Figure 2A shows the first step of preparing the substrate, Figure 2B shows the second step of applying an adhesive layer to an area of the substrate, and Figure 2C shows the step of peeling the film off an area of the adhesive layer. Figure 3 is a schematic diagram illustrating one embodiment of the manufacturing method of the laminate. Figure 3A shows the third step of preparing the reinforcing film, Figure 3B shows the fourth step of placing the soft adherend on one side of the reinforcing film, Figure 3C shows the fifth step of forming the first and second reinforcing film portions by removing a portion of the reinforcing film, and Figure 3D shows the sixth step of improving the adhesive force of the adhesive layer. Figure 4 shows a laminate formed by bending the first and second reinforcing film portions between them, with the first and second reinforcing film portions facing outwards from each other.

1: Laminated body

2: Substrate

3: Adhesive layer

5: Soft adherents

6: The first reinforced membrane part

7: The second reinforcing membrane part

Claims (5)

A laminate characterized in that it comprises a reinforcing film and a soft adherend disposed on one side of the reinforcing film, wherein the reinforcing film comprises a substrate and an adhesive layer disposed on one side of the substrate and comprising a high-adhesion component and a low-adhesion component; the reinforcing film has a first reinforcing film portion and a second reinforcing film portion disposed spaced apart from each other in the direction of the surface of the soft adherend; the first reinforcing film portion and the second reinforcing film portion are disposed spaced apart from each other on the surface of the reinforcing film in a direction orthogonal to the extension direction of the reinforcing film; and the first reinforcing film portion is disposed spaced apart from each other in the direction of the first reinforcing film portion. In both the adhesive layer and the adhesive layer of the second reinforcing film, in the thickness direction, the high-adhesion component is concentrated at the interface between the soft substrate and the adhesive layer, which can cause the laminate to bend between the first and second reinforcing films. In the TOF-SIMS measurement, the ratio of the high-adhesion component in the region starting from the interface between the adhesive layer and the soft substrate and ending at a depth equivalent to 5% of the thickness of the adhesive layer from that interface toward the adhesive layer is more than twice that of the low-adhesion component. As in claim 1, in each of the adhesive layers of the first reinforcing film and the second reinforcing film, on the adhesive layer side further from the interface than the interface, the high-adhesion component and the low-adhesion component are mixed. In TOF-SIMS measurement, from the interface between the adhesive layer and the soft adherend towards the adhesive layer side, with a depth equivalent to 30% of the thickness of the adhesive layer as the starting point and a depth equivalent to 70% of the thickness of the adhesive layer as the ending point, the ratio of the high-adhesion component in the region is 0.8 times to 1.5 times that of the low-adhesion component. For example, in the laminate of claim 1 or 2, the high-adhesion component is a cured polyfunctional (meth)acrylate, and the low-adhesion component is an acrylic polymer. For example, in the laminate of claim 1 or 2, the high-adhesion component is an acrylic polymer and the low-adhesion component is a component containing organosiloxanes. A laminate characterized in that it comprises a reinforcing film and a soft adherend disposed on one side of the reinforcing film, wherein the reinforcing film comprises a substrate and an adhesive layer disposed on one side of the substrate and comprising a high-adhesion component and a low-adhesion component; the reinforcing film has a first reinforcing film portion and a second reinforcing film portion disposed spaced apart from each other in the direction of the surface of the soft adherend; the first reinforcing film portion and the second reinforcing film portion are disposed spaced apart from each other on the surface of the reinforcing film in a direction orthogonal to the extension direction of the reinforcing film; the adhesive force of the adhesive layer is 5 N/25 mm or more; and the thickness of the adhesive layer is 5 mm. For thicknesses of μm or greater, the laminate can be bent between the first reinforcing film portion and the second reinforcing film portion.