JP2020132659A - Reinforcement film, manufacturing method thereof, manufacturing method of device and reinforcement method - Google Patents

Abstract

To provide a reinforcement film excellent in reworkability with lower initial bond strength to an adherend even when an activation treatment has been applied onto a surface of the adherend.SOLUTION: A reinforcement film (10) includes a film base material and an adhesive layer (2) stuck and laminated on one principal surface of the film base material. The adhesive layer includes a photo-curable composition. The photo-curable composition composing the adhesive layer contains a base polymer having a cross-linking structure, a photo-curing agent, and a photoinitiator. The base polymer having a cross-linking structure is formed through a cross-linking reaction of a composition containing a base polymer, a cross-linking agent and a cross-linking accelerator.SELECTED DRAWING: Figure 1

Description

The present invention relates to a reinforcing film in which a film base material and a photocurable pressure-sensitive adhesive layer are fixedly laminated, and a method for producing the same. Further, the present invention relates to a method for manufacturing a device in which a reinforcing film is attached to a surface, and a reinforcing method in which a reinforcing film is fixedly laminated on the surface of an adherend.

An adhesive film may be attached to the surface of an optical device such as a display or an electronic device for the purpose of surface protection, impact resistance imparting, or the like. In such an adhesive film, an adhesive layer is usually fixed and laminated on the main surface of the film base material, and the adhesive layer is attached to the surface of the device via the adhesive layer.

By temporarily attaching the adhesive film to the surface of the device or device component in the state before use such as assembling, processing, and transporting the device, it is possible to suppress damage or breakage of the adherend. It is required that the adhesive film temporarily attached for the purpose of temporary protection of the surface can be easily peeled off from the adherend, and no adhesive residue is generated on the adherend.

Patent Document 1 discloses an adhesive film that is used in a state of being attached to the surface of the device even when the device is used, in addition to assembling, processing, and transporting the device. In addition to surface protection, such an adhesive film has a function of reinforcing the device by dispersing the impact on the device, imparting rigidity to the flexible device, and the like.

When the adhesive film is attached to the adherend, improper attachment such as mixing of air bubbles or deviation of the attachment position may occur. When a bonding failure occurs, the adhesive film is peeled off from the adherend and another adhesive film is bonded (rework). Since the adhesive film used as the process material is designed on the assumption that it is peeled off from the adherend, it is easy to rework. On the other hand, the reinforcing film that is premised on permanent adhesion is generally not expected to be peeled off from the device, and is firmly adhered to the surface of the device, so that rework is difficult.

Patent Document 2 discloses an adhesive film having an adhesive layer which is low in adhesiveness immediately after being bonded to an adherend and is designed so that the adhesive force increases with time. For the adhesive whose adhesive strength is increased by using light or heat as a trigger, the timing of the adhesive strength increase due to hardening after bonding with the adherend can be arbitrarily set. Further, since the adhesive force is small immediately after bonding (before the adhesive force increasing treatment), it can be easily peeled off from the adherend and can be used as a reinforcing film having reworkability.

JP-A-2017-132977 International Publication No. 2015/163115

Before attaching the reinforcing film to the surface of the adherend such as a device, a surface activation treatment such as plasma treatment or corona treatment may be performed for the purpose of cleaning the surface of the adherend. When the reinforcing film is attached to the surface of the adherend after the surface activation treatment, the adhesive strength is significantly increased as compared with the case where the reinforcing film is attached to the adherend which has not been subjected to the surface activation treatment. It may be difficult to peel off (rework) the reinforcing film from the body.

In view of these problems, an object of the present invention is to provide a reinforcing film having a low initial adhesive force to an adherend and excellent reworkability even when the surface of the adherend is activated by plasma or the like.

As a result of studies by the present inventors in view of the above problems, by introducing a cross-linked structure into the base polymer using a cross-linking accelerator, the difference in initial adhesive strength between the presence and absence of surface activation treatment of the adherend is small. It has been found that the adherend that has been surface-activated has excellent reworkability.

The reinforcing film of the present invention includes an adhesive layer fixed and laminated on one main surface of a film base material. The pressure-sensitive adhesive layer comprises a photocurable composition containing a base polymer having a crosslinked structure, a photocuring agent, and a photopolymerization initiator. For example, a composition containing a base polymer, a cross-linking agent, a cross-linking accelerator, a photo-curing agent, and a photopolymerization initiator is applied in layers on a film substrate, and the reaction between the base polymer and the cross-linking agent causes By introducing a crosslinked structure into the base polymer, a reinforcing film in which an adhesive layer is fixedly laminated on a film substrate can be obtained. The pressure-sensitive adhesive layer formed on another substrate may be transferred onto the film substrate.

As the base polymer of the pressure-sensitive adhesive layer, for example, an acrylic polymer is used. A cross-linking structure is introduced into the base polymer by a cross-linking reaction of a composition containing the base polymer, a cross-linking agent and a cross-linking accelerator. For example, the base polymer contains a hydroxy group-containing monomer and / or a carboxy group-containing monomer as a monomer unit, and a cross-linking agent such as a polyfunctional isocyanate compound or a polyfunctional epoxy compound binds to these functional groups to form a cross-linked structure. Is introduced. As the cross-linking accelerator, an organometallic compound is preferably used. Since the pressure-sensitive adhesive composition contains a base polymer into which a cross-linked structure has been introduced using a cross-linking accelerator, the initial adhesive force to the adherend even when the surface of the adherend is activated by plasma treatment or the like. Tends to be suppressed.

The gel fraction of the pressure-sensitive adhesive layer (photocurable composition) may be 60% or more.

The photocuring agent of the pressure-sensitive adhesive layer is, for example, a polyfunctional (meth) acrylate. The functional group equivalent of the photocuring agent is preferably about 100 to 500 g / eq.

After the reinforcing film is temporarily attached to the surface of the adherend, the adhesive layer is irradiated with active light to photo-cure the adhesive layer, so that the adhesive force between the reinforcing film and the adherend is increased and the adherend is adhered. A device is obtained in which a reinforcing film is fixed and laminated on the surface of the body. When the adherend is a polyimide film, the adhesive strength between the pressure-sensitive adhesive layer and the polyimide film is preferably 1 N / 25 mm or less before the pressure-sensitive adhesive layer is photo-cured (temporarily adhered state). Before temporarily attaching the reinforcing film to the adherend, the adherend may be subjected to a surface activation treatment such as plasma treatment.

In the reinforcing film of the present invention, the pressure-sensitive adhesive layer is made of a photocurable composition, and the pressure-sensitive adhesive layer is photo-cured after being adhered to the adherend to increase the adhesive force with the adherend. Before the photocuring of the pressure-sensitive adhesive layer, the adhesive strength is small even for the adherend activated by plasma treatment or the like, so that the rework is easy and the adhesive strength is high after the photocuring.

It is sectional drawing which shows the laminated structure of the reinforcing film. It is sectional drawing which shows the laminated structure of the reinforcing film. It is sectional drawing which shows the device which attached the reinforcing film.

FIG. 1 is a cross-sectional view showing an embodiment of a reinforcing film. The reinforcing film 10 includes an adhesive layer 2 on one main surface of the film base material 1. The pressure-sensitive adhesive layer 2 is fixedly laminated on one main surface of the base film 1. The pressure-sensitive adhesive layer 2 is a photo-curable pressure-sensitive adhesive made of a photo-curable composition, and is cured by irradiation with active light rays such as ultraviolet rays to increase the adhesive force with an adherend.

FIG. 2 is a cross-sectional view of a reinforcing film in which a separator 5 is temporarily attached on the main surface of the pressure-sensitive adhesive layer 2. FIG. 3 is a cross-sectional view showing a state in which the reinforcing film 10 is attached to the surface of the device 20.

The reinforcing film 10 is attached to the surface of the device 20 by peeling off the separator 5 from the surface of the adhesive layer 2 and attaching the exposed surface of the adhesive layer 2 to the surface of the device 20. In this state, the pressure-sensitive adhesive layer 2 is before photo-curing, and the reinforcing film 10 (adhesive layer 2) is temporarily attached to the device 20. By photocuring the pressure-sensitive adhesive layer 2, the adhesive force at the interface between the device 20 and the pressure-sensitive adhesive layer 2 is increased, and the device 20 and the reinforcing film 10 are fixed to each other.

"Fixing" is a state in which two laminated layers are firmly adhered to each other, and peeling at the interface between the two layers is impossible or difficult. "Temporary adhesion" is a state in which the adhesive force between the two laminated layers is small and can be easily peeled off at the interface between the two layers.

In the reinforcing film shown in FIG. 2, the film base material 1 and the pressure-sensitive adhesive layer 2 are fixed to each other, and the separator 5 is temporarily attached to the pressure-sensitive adhesive layer 2. When the film base material 1 and the separator 5 are peeled off, peeling occurs at the interface between the pressure-sensitive adhesive layer 2 and the separator 5, and the state in which the pressure-sensitive adhesive layer 2 is fixed on the film base material 1 is maintained. No adhesive remains on the separator 5 after peeling.

In the device to which the reinforcing film 10 shown in FIG. 3 is attached, the device 20 and the adhesive layer 2 are temporarily attached before the photocuring of the adhesive layer 2. When the film base material 1 and the device 20 are peeled off, peeling occurs at the interface between the pressure-sensitive adhesive layer 2 and the device 20, and the state in which the pressure-sensitive adhesive layer 2 is fixed on the film base material 1 is maintained. Since no adhesive remains on the device 20, rework is easy. After the pressure-sensitive adhesive layer 2 is photo-cured, the adhesive force between the pressure-sensitive adhesive layer 2 and the device 20 increases, so that it is difficult to peel the film 1 from the device 20, and when both are peeled off, the pressure-sensitive adhesive layer 2 aggregates. Destruction may occur.

[Structure of reinforcing film]
<Film base material>
A plastic film is used as the film base material 1. In order to fix the film base material 1 and the pressure-sensitive adhesive layer 2, it is preferable that the surface of the film base material 1 attached to the pressure-sensitive adhesive layer 2 is not subjected to a mold release treatment.

The thickness of the film base material is, for example, about 4 to 500 μm. From the viewpoint of reinforcing the device by imparting rigidity, cushioning the impact, etc., the thickness of the film substrate 1 is preferably 12 μm or more, more preferably 30 μm or more, still more preferably 45 μm or more. From the viewpoint of giving flexibility to the reinforcing film and improving handleability, the thickness of the film base material 1 is preferably 300 μm or less, more preferably 200 μm or less. From the viewpoint of achieving both flexibility and mechanical strength, compressive strength of the film substrate 1 is preferably 100~3000kg / cm ^2, more preferably ^{200~2900kg / cm 2, 300~2800kg / cm} 2 and more Preferably, 400 to 2700 kg / cm ² is particularly preferable.

Examples of the plastic material constituting the film base material 1 include polyester-based resin, polyolefin-based resin, cyclic polyolefin-based resin, polyamide-based resin, and polyimide-based resin. In a reinforcing film for an optical device such as a display, the film base material 1 is preferably a transparent film. Further, when the pressure-sensitive adhesive layer 2 is photo-cured by irradiating the film base material 1 with active light rays, the film base material 1 preferably has transparency to the active light rays used for curing the pressure-sensitive adhesive layer. Polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate are preferably used because they have both mechanical strength and transparency. When the pressure-sensitive adhesive layer is cured by irradiating the adhesive layer from the adherend side, it is sufficient that the adherend has transparency to the active light rays, and the film base material 1 is not transparent to the active rays. May be good.

The surface of the film base material 1 may be provided with a functional coating such as an easy-adhesion layer, an easy-slip layer, a release layer, an antistatic layer, a hard coat layer, and an antireflection layer. As described above, in order to fix the film base material 1 and the pressure-sensitive adhesive layer 2, it is preferable that the release layer is not provided on the surface of the film base material 1 attached to the pressure-sensitive adhesive layer 2.

<Adhesive layer>
The pressure-sensitive adhesive layer 2 fixed and laminated on the film substrate 11 is composed of a photocurable composition containing a base polymer, a photocuring agent and a photopolymerization initiator. Before photo-curing, the pressure-sensitive adhesive layer 2 has a small adhesive force with an adherend such as a device or a device component, so that rework is easy. Since the adhesive layer 2 is photocured to improve the adhesive force with the adherend, the reinforcing film is difficult to peel off from the device surface even when the device is used, and the adhesive reliability is excellent.

When the reinforcing film is used for an optical device such as a display, the total light transmittance of the pressure-sensitive adhesive layer 2 is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more. The haze of the pressure-sensitive adhesive layer 2 is preferably 2% or less, more preferably 1% or less, further preferably 0.7% or less, and particularly preferably 0.5% or less.

(Base polymer)
The base polymer is the main constituent of the pressure-sensitive adhesive composition. The type of the base polymer is not particularly limited, and an acrylic polymer, a silicone polymer, a urethane polymer, a rubber polymer, or the like may be appropriately selected. In particular, since the pressure-sensitive adhesive composition is excellent in optical transparency and adhesiveness, and the adhesiveness can be easily controlled, the pressure-sensitive adhesive composition preferably contains an acrylic polymer as a base polymer, and the weight of the pressure-sensitive adhesive composition is 50. % Or more is preferably an acrylic polymer.

As the acrylic polymer, those containing a (meth) acrylic acid alkyl ester as a main monomer component are preferably used. In addition, in this specification, "(meth) acrylic" means acrylic and / or methacrylic.

As the (meth) acrylic acid alkyl ester, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferably used. The alkyl group of the (meth) acrylic acid alkyl ester may be linear or may have branches. Examples of (meth) acrylic acid alkyl esters include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, butyl (meth) acrylic acid, isobutyl (meth) acrylic acid, s-butyl (meth) acrylic acid, ( T-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-2-. Ethylhexyl, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate , (Meta) dodecyl acrylate, (meth) isotridodecyl acrylate, (meth) tetradecyl acrylate, (meth) isotetradecyl acrylate, (meth) pentadecyl acrylate, (meth) cetyl acrylate, (meth) Examples thereof include heptadecyl acrylate, octadecyl (meth) acrylate, isooctadecil (meth) acrylate, nonadecil (meth) acrylate, and aralkyl (meth) acrylate.

The content of the (meth) acrylic acid alkyl ester is preferably 40% by weight or more, more preferably 50% by weight or more, still more preferably 55% by weight or more, based on the total amount of the monomer components constituting the base polymer.

The acrylic base polymer contains a monomer component having a crosslinkable functional group as a copolymerization component. By introducing the crosslinked structure into the base polymer, the cohesive force is improved, the adhesive force of the pressure-sensitive adhesive layer 2 is improved, and the adhesive residue on the adherend during rework tends to be reduced.

Examples of the monomer having a crosslinkable functional group include a hydroxy group-containing monomer and a carboxy group-containing monomer. The herodoxy group and carboxy group of the base polymer serve as reaction points with the cross-linking agent described later. For example, when an isocyanate-based cross-linking agent is used, it is preferable to contain a hydroxy group-containing monomer as a copolymerization component of the base polymer. When an epoxy-based cross-linking agent is used, it is preferable to contain a carboxy group-containing monomer as a copolymerization component of the base polymer.

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and (meth). Examples thereof include 8-hydroxyoctyl acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and 4- (hydroxymethyl) cyclohexyl) methyl (meth) acrylate. Examples of the carboxy group-containing monomer include (meth) acrylic acid, 2-carboxyethyl (meth) acrylic acid, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

In the acrylic base polymer, the total amount of the hydroxy group-containing monomer and the carboxy group-containing monomer is preferably 1 to 30% by weight, more preferably 2 to 25% by weight, based on the total amount of the constituent monomer components. It is more preferably 20% by weight.

The acrylic-based base polymer contains N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazin, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholin, and N-acryloylmorpholin as constituent monomer components. , N-vinylcarboxylic acid amides, N-vinylcaprolactam and other nitrogen-containing monomers may be contained.

The acrylic base polymer may contain a monomer component other than the above. The acrylic-based base polymer contains, for example, vinyl ester monomer, aromatic vinyl monomer, epoxy group-containing monomer, vinyl ether monomer, sulfo group-containing monomer, phosphoric acid group-containing monomer, acid anhydride group-containing monomer and the like as monomer components. You may.

The base polymer before the introduction of the crosslinked structure may be substantially free of nitrogen atoms. The proportion of nitrogen in the constituent elements of the base polymer is 0.1 mol% or less, 0.05 mol% or less, 0.01 mol% or less, 0.005 mol% or less, 0.001 mol% or less, or 0. There may be. By using a base polymer that substantially does not contain nitrogen atoms, an increase in the adhesive strength (initial adhesive strength) of the pressure-sensitive adhesive layer before photo-curing is suppressed when the adherend is subjected to surface activation treatment. Tend.

By not using a nitrogen atom-containing monomer such as a cyano group-containing monomer, a lactam structure-containing monomer, an amide group-containing monomer, or a morpholin ring-containing monomer as a constituent monomer component of the base polymer, a base polymer substantially free of nitrogen atoms can be obtained. can get. When the base polymer is substantially free of nitrogen atoms, the base polymer preferably contains a carboxy group-containing monomer as a monomer component from the viewpoint of enhancing the cohesiveness of the pressure-sensitive adhesive.

The adhesive properties of the pressure-sensitive adhesive before photo-curing are susceptible to the constituents and molecular weight of the base polymer. The higher the molecular weight of the base polymer, the harder the adhesive tends to be. The weight average molecular weight of the acrylic base polymer is preferably 100,000 to 5 million, more preferably 300,000 to 3 million, and even more preferably 500,000 to 2 million. When a crosslinked structure is introduced into the base polymer, the molecular weight of the base polymer refers to the molecular weight before the introduction of the crosslinked structure.

When the base polymer contains a high Tg monomer as a constituent monomer component, the cohesive force of the pressure-sensitive adhesive is improved, the reworkability is excellent before photo-curing, and the adhesive phosphorus property tends to be high after photo-curing. The high Tg monomer means a monomer having a high glass transition temperature (Tg) of the homopolymer. Examples of the monomer having a Tg of 40 ° C. or higher in the homopolymer include dicyclopentanyl methacrylate (Tg: 175 ° C.), dicyclopentanyl acrylate (Tg: 120 ° C.), isobornyl methacrylate (Tg: 173 ° C.), and isobol. (Meta) acrylic acid esters such as nyl acrylate (Tg: 97 ° C.), methyl methacrylate (Tg: 105 ° C.), 1-adamantyl methacrylate (Tg: 250 ° C.), 1-adamantyl acrylate (Tg: 153 ° C.); acryloylmorpholin (Tg: 145 ° C), dimethylacrylamide (Tg: 119 ° C), diethylacrylamide (Tg: 81 ° C), dimethylaminopropylacrylamide (Tg: 134 ° C), isopropylacrylamide (Tg: 134 ° C), hydroxyethylacrylamide (Tg) : 98 ° C.) and other amide group-containing vinyl monomers; acrylate compounds (Tg: 228 ° C.), acrylic acids (Tg: 106 ° C.) and other acid monomers; N-vinylpyrrolidone (Tg: 54 ° C.) and the like.

In the acrylic base polymer, the content of the monomer having a Tg of 40 ° C. or higher in the homopolymer is preferably 1 to 50% by weight, more preferably 3 to 40% by weight, based on the total amount of the constituent monomer components. .. In order to form a pressure-sensitive adhesive layer having appropriate hardness and excellent reworkability, it is preferable that the monomer component of the base polymer contains a monomer component having a homopolymer Tg of 80 ° C. or higher, and the homopolymer Tg is It is more preferable to contain a monomer component of 100 ° C. or higher. In the acrylic base polymer, the content of the monomer having a Tg of 100 ° C. or higher of the homopolymer with respect to the total amount of the constituent monomer components is preferably 0.1% by weight or more, more preferably 0.5% by weight or more. It is more preferably 1% by weight or more, and particularly preferably 3% by weight or more.

An acrylic polymer as a base polymer can be obtained by polymerizing the above-mentioned monomer components by various known methods such as solution polymerization, emulsion polymerization and bulk polymerization. The solution polymerization method is preferable from the viewpoint of the balance of properties such as adhesive strength and holding power of the pressure-sensitive adhesive and the cost. Ethyl acetate, toluene and the like are used as the solvent for solution polymerization. The solution concentration is usually about 20 to 80% by weight. As the polymerization initiator used for solution polymerization, various known ones such as azo type and peroxide type can be used. Chain transfer agents may be used to adjust the molecular weight. The reaction temperature is usually about 50 to 80 ° C., and the reaction time is usually about 1 to 8 hours.

(Oligomer)
The pressure-sensitive adhesive composition may contain an oligomer in addition to the base polymer. For example, the pressure-sensitive adhesive composition may contain an acrylic oligomer in addition to the acrylic base polymer. As the oligomer, one having a weight average molecular weight of about 1000 to 30,000 is used. Acrylic oligomers contain (meth) acrylic acid alkyl esters as the main constituent monomer components. From the viewpoint of enhancing the adhesive strength of the pressure-sensitive adhesive layer 2 after photo-curing, the glass transition temperature of the acrylic oligomer is preferably 40 ° C. or higher, more preferably 50 ° C. or higher. The oligomer may contain crosslinkable functional groups as well as the base polymer.

The content of the oligomer in the pressure-sensitive adhesive composition is not particularly limited. When the pressure-sensitive adhesive composition contains an acrylic oligomer in addition to the acrylic base polymer, the amount of the oligomer per 100 parts by weight of the base polymer is 0.1 to 20 parts by weight from the viewpoint of adjusting the adhesive strength within an appropriate range. Preferably, 0.3 to 10 parts by weight is more preferable, and 0.5 to 5 parts by weight is further preferable.

(Crosslinking agent)
By introducing a crosslinked structure into the base polymer, the pressure-sensitive adhesive can have an appropriate cohesive force. For example, a cross-linked structure is introduced by adding a cross-linking agent to the solution obtained by polymerizing the base polymer and heating as necessary. The cross-linking agent has two or more cross-linking functional groups in one molecule. The cross-linking agent may have three or more cross-linking functional groups in one molecule.

Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, carbodiimide-based cross-linking agents, and metal chelate-based cross-linking agents. These cross-linking agents react with functional groups such as hydroxy groups and carboxy groups introduced into the base polymer to form a cross-linked structure. Isocyanate-based cross-linking agents and epoxy-based cross-linking agents are preferable because they have high reactivity with the hydroxy group and carboxy group of the base polymer and can easily introduce a cross-linked structure.

As the isocyanate-based cross-linking agent, polyisocyanate having two or more isocyanate groups in one molecule is used. The isocyanate-based cross-linking agent may have three or more isocyanate groups in one molecule. Examples of the isocyanate-based cross-linking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; 2,4-tolylene diisocyanate. Aromatic isocyanates such as isocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate; trimethylolpropane / trimylene diisocyanate trimer adduct (eg, "Coronate L" manufactured by Toso), trimethylolpropane / hexamethylene Diisocyanate trimeric adduct (eg, "Coronate HL" manufactured by Toso), trimethylolpropane adduct of xylylene diisocyanate (eg, "Takenate D110N" manufactured by Mitsui Chemicals), isocyanurate of hexamethylene diisocyanate (eg, manufactured by Toso). Examples thereof include isocyanate additives such as "Coronate HX").

As the epoxy-based cross-linking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule is used. The epoxy-based cross-linking agent may have three or more or four or more epoxy groups in one molecule. The epoxy group of the epoxy-based cross-linking agent may be a glycidyl group. Examples of the epoxy-based cross-linking agent include N, N, N', N'-tetraglycidyl-m-xylene diamine, diglycidyl aniline, 1,3-bis (N, N-diglycidyl aminomethyl) 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, penta Ellisritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipate diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, Examples thereof include resorcin diglycidyl ether and bisphenol-S-diglycidyl ether. As the epoxy-based cross-linking agent, commercially available products such as "Denacol" manufactured by Nagase ChemteX and "Tetrad X" and "Tetrad C" manufactured by Mitsubishi Gas Chemical Company may be used.

The cross-linking agent may contain nitrogen atoms even if the base polymer is substantially free of nitrogen atoms. For example, a crosslinked structure may be introduced into a base polymer substantially free of nitrogen atoms by using an isocyanate crosslinker. When the base polymer does not contain nitrogen atoms substantially, by using a cross-linking agent that does not contain nitrogen atoms such as an epoxy-based cross-linking agent, the difference in initial adhesive strength depending on the presence or absence of surface activation treatment such as plasma treatment becomes larger. It tends to be smaller.

The amount of the cross-linking agent used may be appropriately adjusted according to the composition and molecular weight of the base polymer. The amount of the cross-linking agent used is about 0.01 to 10 parts by weight, preferably 0.1 to 7 parts by weight, more preferably 0.2 to 6 parts by weight, still more preferably, with respect to 100 parts by weight of the base polymer. Is 0.3 to 5 parts by weight. The value obtained by dividing the amount of the cross-linking agent used (parts by weight) with respect to 100 parts by weight of the base polymer by the functional group equivalent (g / eq) of the cross-linking agent is preferably 0.00015 to 0.11 and 0.001 to 0. .077 is more preferred, 0.003 to 0.055 is even more preferred, and 0.0045 to 0.044 is particularly preferred. By using a larger amount of cross-linking agent than a general acrylic transparent adhesive for optics for permanent adhesion and giving the adhesive an appropriate hardness, glue to the adherend during rework The rest tends to decrease and the reworkability tends to improve.

(Crosslink accelerator)
The pressure-sensitive adhesive composition contains a cross-linking accelerator in addition to the cross-linking agent. By using the cross-linking accelerator, the cross-linking reaction (introduction of the cross-linking structure into the base polymer) can be efficiently promoted. In addition, by introducing a cross-linked structure into the base polymer using a cross-linking accelerator, the pressure-sensitive adhesive layer of the reinforcing film tends to show low initial adhesive strength even to an adherend whose surface has been activated. is there.

Examples of the cross-linking accelerator include organometallic complexes (chelates), organometallic compounds such as compounds of metals and alkoxy groups, and compounds of metals and acyloxy groups; and tertiary amines. In particular, an organometallic compound is preferable from the viewpoint of suppressing the progress of the crosslinking reaction in a solution state at room temperature and ensuring the pot life of the pressure-sensitive adhesive composition. Further, since it is easy to introduce a uniform cross-linked structure over the entire thickness direction of the pressure-sensitive adhesive layer, an organometallic compound that is liquid at room temperature is preferable as the cross-linking accelerator.

Examples of the metal of the organometallic compound include iron, tin, aluminum, zirconium, zinc, titanium, lead, cobalt and zinc.

Examples of iron-based cross-linking accelerators include tris (acetylacetonate) iron, tris (hexane-2,4-geonate) iron, tris (heptane-2,4-geonate) iron, and tris (heptane-3,5-geonate). Iron, Tris (5-methylhexane-2,4-geonate) iron, Tris (octane-2,4-geonate) iron, Tris (6-methylheptane-2,4-geonate) iron, Tris (2,6-dinate) Dimethylheptane-3,5-geonate) iron, tris (nonan-2,4-geonate) iron, tris (nonan-4,6-geonate) iron, tris (2,2,6,6-tetramethylheptane-3) , 5-Gionate) Iron, Tris (Tridecane-6,8-Gionate) Iron, Tris (1-phenylbutane-1,3-Zionate) Iron, Tris (Hexafluoroacetylacetonate) Iron, Tris (Ethyl Acetate) Iron, Tris (acetoacetate-n-propyl) iron, Tris (isopropylacetate isopropyl) iron, Tris (acetoacetate-n-butyl) iron, Tris (acetoacetate-sec-butyl) iron, Tris (acetoacetate-tert- Butyl) iron, tris (methyl propionyl acetate) iron, tris (ethyl propionyl acetate) iron, tris (propionyl acetate-n-propyl) iron, tris (isopropyl propionyl acetate) iron, tris (propionyl acetate-n-butyl) iron, Tris (propionyl acetate-sec-butyl) iron, tris (propionyl acetate-tert-butyl) iron, tris (acetoacetate benzyl) iron, tris (dimethyl malonate) iron, tris (diethyl malonate) iron, trimethoxy iron, triethoxy Examples include iron and triisopropoxy iron.

Examples of the tin-based cross-linking accelerator include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin maleate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, tributyltin methoxyde, tributyltin acetate, and triethyltinethoxydo. Examples thereof include tributyltin ethoxydo, dioctyltin oxide, dioctyltin dilaurate, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate and the like.

As aluminum-based cross-linking accelerators, aluminum diisopropyrate monosec-butyrate, aluminum sec-butyrate, aluminum isopropylate, aluminum ethylate, aluminum ethylacetate acetate diisopropyrate, aluminum trisethylacetate, aluminum alkylacetate diisopropi Examples include rate, aluminum monoacetylacetonatebis (ethylacetacetate), aluminum trisacetylacetonate and the like.

Examples of the zirconium-based cross-linking accelerator include zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium tributoxymonoacetonate, zirconium naphthenate, zirconium propoxide, zirconium butoxide and the like.

Examples of the zinc-based cross-linking accelerator include zinc naphthenate and zinc 2-ethylhexanoate.

Examples of titanium-based cross-linking accelerators include dibutyl titanium dichloride, tetrabutyl titanate, tetraisopropyl titanate, tetraoctyl titanate, butoxytitanium trichloride, titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetate acetate, and titanium lactate ammonium salt. Examples thereof include titanium triethanol aminate, titanium diisopropoxybisacetylacetonate, titanium isostearate, titanium diethanol aminate, and titanium aminoethylaminoethanolate.

Examples of the lead-based cross-linking accelerator include lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate and the like.

Examples of the cobalt-based cross-linking accelerator include cobalt 2-ethylhexanoate and cobalt benzoate.

The amount of the cross-linking accelerator used may be appropriately adjusted according to the type and amount of the cross-linking agent and the type of the cross-linking accelerator. The amount of the cross-linking accelerator used is generally about 0.001 to 2 parts by weight with respect to 100 parts by weight of the base polymer.

When a cross-linking accelerator is used for the epoxy-based cross-linking agent, the amount of the cross-linking accelerator used is preferably 0.01 to 2.0 parts by weight with respect to 100 parts by weight of the base polymer. As the epoxy-based cross-linking agent, it is preferable to use a non-tin-based organic metal as the cross-linking accelerator. When a cross-linking accelerator is used with respect to the isocyanate-based cross-linking agent, the amount of the cross-linking accelerator used is preferably 0.001 to 0.1 parts by weight.

The pressure-sensitive adhesive composition may contain a cross-linking retarder in addition to the cross-linking accelerator. By adding the cross-linking retarder, it is possible to suppress the progress of the cross-linking reaction in a solution state at room temperature and prolong the pot life of the pressure-sensitive adhesive composition. Examples of the cross-linking retarder include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate and stearyl acetoacetate; β-ketoesters such as acetylacetone, 2,4-hexanedione and benzoylacetone. Diketone; alcohols such as tert-butyl alcohol can be mentioned. Of these, β-diketone is preferable, and acetylacetone is particularly preferable. The amount of the cross-linking retarder used is about 0.1 to 30 parts by weight, preferably 25 parts by weight or less, and more preferably 20 parts by weight or less with respect to 100 parts by weight of the total amount of the pressure-sensitive adhesive composition.

(Photo-curing agent)
The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 2 contains a photocuring agent in addition to the base polymer. When the pressure-sensitive adhesive layer 2 made of the photocurable pressure-sensitive adhesive composition is photo-cured after being bonded to the adherend, the adhesive strength with the adherend is improved.

The photocuring agent has two or more polymerizable functional groups in one molecule. The polymerizable functional group is preferably one having polymerizability by a photoradical reaction, and the photocuring agent is preferably a compound having two or more ethylenically unsaturated bonds in one molecule. Further, the photocuring agent is preferably a compound showing compatibility with the base polymer. The photocuring agent is preferably a liquid at room temperature because it exhibits appropriate compatibility with the base polymer. When the photo-curing agent is compatible with the base polymer and uniformly dispersed in the composition, it is possible to secure a contact area with the adherend and to form a highly transparent pressure-sensitive adhesive layer 2. Further, since the base polymer and the photocuring agent show appropriate compatibility, the crosslinked structure by the photocuring agent can be easily introduced uniformly into the pressure-sensitive adhesive layer 2 after the photocuring, and the adhesive force with the adherend can be improved. Tends to rise properly.

The compatibility of the base polymer with the photocuring agent is mainly influenced by the structure of the compound. The structure and compatibility of the compound can be evaluated by, for example, the Hansen solubility parameter, and the smaller the difference between the solubility parameters of the base polymer and the photocuring agent, the higher the compatibility tends to be.

It is preferable to use a polyfunctional (meth) acrylate as a photocuring agent because it has high compatibility with an acrylic base polymer. Examples of the polyfunctional (meth) acrylate include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, bisphenol A ethylene oxide-modified di (meth) acrylate, and bisphenol A propylene oxide. Modified di (meth) acrylate, alcandiol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate, pentaeristol tri (meth) acrylate, pentaeristol di ( Meta) Acrylate, Trimethylol Propanetri (Meta) Acrylate, Ditrimethylol Propanetetra (Meta) Acrylate, Pentaeristol Tetra (Meta) Acrylate, Penta Eristol Tetra (Meta) Acrylate, Dipenta Eristol Poly (Meta) Acrylate, dipentaeryristolhexa (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerindi (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, butadiene (meth) acrylate, isoprene (meth) Examples include acrylate. Among these, polyethylene glycol di (meth) acrylate or polypropylene glycol di (meth) acrylate is preferable, and polyethylene glycol di (meth) acrylate is particularly preferable, because it is excellent in compatibility with an acrylic base polymer.

The compatibility of the base polymer with the photocuring agent also depends on the molecular weight of the compound. The smaller the molecular weight of the photocurable compound, the higher the compatibility with the base polymer tends to be. From the viewpoint of compatibility with the base polymer, the molecular weight of the photocuring agent is preferably 1500 or less, more preferably 1000 or less, further preferably 500 or less, and particularly preferably 400 or less.

From the viewpoint of high compatibility with the base polymer and improvement of the adhesive force after photocuring, the functional group equivalent (g / eq) of the photocuring agent is preferably 500 or less, more preferably 400 or less, and further 300 or less. It is preferable, and 200 or less is particularly preferable. On the other hand, if the functional group equivalent of the photo-curing agent is excessively small, the cross-linking point density of the pressure-sensitive adhesive layer after photo-curing becomes high, and the adhesiveness may decrease. Therefore, the functional group equivalent of the photocuring agent is preferably 80 or more, more preferably 100 or more, and even more preferably 130 or more.

In the combination of the acrylic base polymer and the polyfunctional acrylate photocuring agent, when the functional group equivalent of the photocuring agent is small, the interaction between the base polymer and the photocuring agent is strong, the initial adhesive force is increased, and the reworkability is increased. May lead to a decrease in From the viewpoint of maintaining the adhesive force between the pressure-sensitive adhesive layer 2 and the adherend before photo-curing in an appropriate range, the functional group equivalent of the photo-curing agent is preferably within the above range.

The content of the photocuring agent in the pressure-sensitive adhesive composition is preferably 10 to 50 parts by weight with respect to 100 parts by weight of the base polymer. By setting the blending amount of the photo-curing agent within the above range, the adhesiveness between the pressure-sensitive adhesive layer and the adherend after photo-curing can be adjusted within an appropriate range. The content of the photocuring agent is more preferably 15 to 45 parts by weight, still more preferably 20 to 40 parts by weight, based on 100 parts by weight of the base polymer.

(Photopolymerization initiator)
The photopolymerization initiator generates active species by irradiation with active light rays and promotes the curing reaction of the photocuring agent. As the photopolymerization initiator, a photocation initiator (photoacid generator), a photoradical initiator, a photoanion initiator (photobase generator) and the like are used depending on the type of photocuring agent and the like. When an ethylenically unsaturated compound such as a polyfunctional acrylate is used as the photocuring agent, it is preferable to use a photoradical initiator as the polymerization initiator.

The photoradical initiator generates radicals by irradiation with active light, and promotes the radical polymerization reaction of the photocurable agent by the radical transfer from the photoradical initiator to the photocuring agent. As the photoradical initiator (photoradical generator), those that generate radicals by irradiation with visible light or ultraviolet rays having a wavelength shorter than 450 nm are preferable, and hydroxyketones, benzyldimethylketals, aminoketones, and acylphosphine are preferable. Examples thereof include oxides, benzophenones, and trichloromethyl group-containing triazine derivatives. The photoradical initiator may be used alone or in combination of two or more.

When transparency is required for the pressure-sensitive adhesive layer 2, the photopolymerization initiator preferably has a lower sensitivity to light having a wavelength longer than 400 nm (visible light), and for example, has an extinction coefficient at a wavelength of 405 nm of 1 × 10 ² [. A photopolymerization initiator having a capacity of mL g ^-1 cm ^-1 ] or less is preferably used.

The content of the photopolymerization initiator in the pressure-sensitive adhesive layer 2 is preferably 0.01 to 5 parts by weight, more preferably 0.02 to 3 parts by weight, and 0.03 to 2 parts by weight with respect to 100 parts by weight of the base polymer. The part is more preferable. The content of the photopolymerization initiator in the pressure-sensitive adhesive layer 2 is preferably 0.02 to 10 parts by weight, more preferably 0.05 to 7 parts by weight, and 0.1 to 5 parts by weight with respect to 100 parts by weight of the photocuring agent. Parts by weight are more preferred.

(Other additives)
In addition to the above-exemplified components, the pressure-sensitive adhesive layer includes a silane coupling agent, a tackifier, a plasticizer, a softening agent, an antioxidant, an antioxidant, a filler, a colorant, and an ultraviolet absorber surfactant. Additives such as antistatic agents may be contained within a range that does not impair the characteristics of the present invention.

[Making a reinforcing film]
A reinforcing film can be obtained by laminating the photocurable pressure-sensitive adhesive layer 2 on the film base material 1. The pressure-sensitive adhesive layer 2 may be formed directly on the film base material 1, or the pressure-sensitive adhesive layer formed in a sheet shape on another base material may be transferred onto the film base material 1.

The above adhesive composition can be applied by roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coat, etc. The pressure-sensitive adhesive layer is formed by applying the coating on the substrate and, if necessary, drying and removing the solvent. As a drying method, an appropriate method can be appropriately adopted. The heating and drying temperature is preferably 40 ° C. to 200 ° C., more preferably 50 ° C. to 180 ° C., and even more preferably 70 ° C. to 170 ° C. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, still more preferably 10 seconds to 10 minutes.

The thickness of the pressure-sensitive adhesive layer 2 is, for example, about 1 to 300 μm. The thicker the pressure-sensitive adhesive layer 2, the better the adhesiveness with the adherend tends to be. On the other hand, if the thickness of the pressure-sensitive adhesive layer 2 is excessively large, the fluidity before photo-curing is high, and handling may be difficult. Therefore, the thickness of the pressure-sensitive adhesive layer 2 is preferably 5 to 100 μm, more preferably 8 to 50 μm, further preferably 10 to 40 μm, and particularly preferably 13 to 30 μm.

It is preferable to proceed the cross-linking by heating or aging at the same time as the solvent is dried or after the solvent is dried. The heating temperature and heating time are appropriately set depending on the type of the cross-linking agent and the cross-linking accelerator used, and usually, cross-linking is performed by heating in the range of 20 ° C. to 160 ° C. for about 1 minute to 7 days. The heating for drying and removing the solvent may also serve as the heating for crosslinking.

The introduction of a crosslinked structure into the base polymer increases the gel fraction. The higher the gel fraction, the harder the adhesive, and when the reinforcing film is peeled off from the adherend by rework or the like, the adhesive residue on the adherend tends to be suppressed. The gel fraction of the pressure-sensitive adhesive layer 2 before photo-curing is preferably 30% or more, more preferably 50% or more, further preferably 60% or more, and particularly preferably 65% or more. The gel fraction of the pressure-sensitive adhesive layer 2 before photo-curing may be 70% or more or 75% or more.

Since the pressure-sensitive adhesive contains an unreacted photo-curing agent, the gel fraction of the pressure-sensitive adhesive layer 2 before photo-curing is generally 90% or less. If the gel fraction of the pressure-sensitive adhesive layer 2 before photo-curing is excessively large, the anchoring force on the adherend may decrease, and the initial adhesive force may be insufficient. Therefore, the gel fraction of the pressure-sensitive adhesive layer 2 before photo-curing is preferably 85% or less, more preferably 80% or less.

The gel fraction can be determined as an insoluble component in a solvent such as ethyl acetate. Specifically, the insoluble component after immersing the pressure-sensitive adhesive layer in ethyl acetate at 23 ° C. for 7 days with respect to the sample before immersion. It is calculated as a weight fraction (unit: weight%). In general, the gel fraction of a polymer is equal to the degree of cross-linking, and the more cross-linked portions in the polymer, the higher the gel fraction. Therefore, the larger the amount of the cross-linking agent used (the content of the cross-linking functional group), the larger the gel fraction tends to be. Further, by using the cross-linking accelerator, the amount of unreacted functional groups of the cross-linking agent is reduced, so that the gel fraction tends to be large. In the pressure-sensitive adhesive layer 2 before photo-curing, the photo-curing agent is in an unreacted state, so that the larger the amount of the photo-curing agent, the smaller the gel fraction.

Even after the cross-linked structure is introduced into the polymer by the cross-linking agent, the photo-curing agent remains unreacted. Therefore, a photocurable pressure-sensitive adhesive layer 2 containing a base polymer and a photocurable agent is formed. When the pressure-sensitive adhesive layer 2 is formed on the film base material 1, it is preferable to attach the separator 5 on the pressure-sensitive adhesive layer 2 for the purpose of protecting the pressure-sensitive adhesive layer 2. Crosslinking may be performed after attaching the separator 5 on the pressure-sensitive adhesive layer 2.

When the pressure-sensitive adhesive layer 2 is formed on another base material, the reinforcing film is obtained by transferring the pressure-sensitive adhesive layer 2 onto the film base material 1 after drying the solvent. The base material used for forming the pressure-sensitive adhesive layer may be used as it is as the separator 5.

As the separator 5, a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, or polyester film is preferably used. The thickness of the separator is usually about 3 to 200 μm, preferably about 10 to 100 μm. The contact surface of the separator 5 with the pressure-sensitive adhesive layer 2 is subjected to a mold release treatment such as a silicone-based, fluorine-based, long-chain alkyl-based, or fatty acid amide-based mold release agent, or silica powder. Is preferable. Since the surface of the separator 5 is mold-released, when the film base material 1 and the separator 5 are peeled off, peeling occurs at the interface between the pressure-sensitive adhesive layer 2 and the separator 5, and the pressure-sensitive adhesive is applied onto the film base material 1. The state in which the layer 2 is fixed is maintained.

[Use of reinforcing film]
The reinforcing film of the present invention is used by being bonded to a device or a device component. The adherend to which the reinforcing film is attached is not particularly limited, and examples thereof include various electronic devices, optical devices, and components thereof. The reinforcing film may be attached to the entire surface of the adherend, or may be selectively attached only to the portion requiring reinforcement. Further, after the reinforcing film is attached to the entire surface of the adherend, the reinforcing film at a portion that does not require reinforcement may be cut and the reinforcing film may be peeled off and removed. Before the pressure-sensitive adhesive is photo-cured, the reinforcing film is temporarily attached to the surface of the adherend, so that the reinforcing film can be easily peeled off and removed from the surface of the adherend.

By laminating the reinforcing film, appropriate rigidity is imparted, which is expected to improve handleability and prevent damage. When the reinforcing film is attached to the work-in-process in the manufacturing process of the device, the reinforcing film may be attached to the large-sized work-in-process before being cut to the product size. A reinforcing film may be attached roll-to-roll to the mother roll of the device manufactured by the roll-to-roll process.

<Characteristics of adhesive layer before photo-curing>
In the reinforcing film 10, the pressure-sensitive adhesive layer 2 is fixed to the film base material 1, and the adhesive force to the adherend is small after bonding with the adherend and before photocuring. Therefore, the reinforcing film can be easily peeled off from the adherend before photo-curing, and the reworkability is excellent. Further, before photo-curing, the reinforcing film can be easily cut to remove the reinforcing film in a part of the surface of the adherend.

(Adhesive strength)
From the viewpoint of facilitating peeling from the adherend and preventing adhesive residue on the adherend after peeling the reinforcing film, the adhesive strength between the adhesive layer 2 before photocuring and the adherend is 1.5 N / It is preferably 25 mm or less, more preferably 1 N / 25 mm or less, further preferably 0.7 N / 25 mm or less, and particularly preferably 0.5 N / 25 mm or less. The adhesive strength between the pressure-sensitive adhesive layer 2 and the adherend before photo-curing may be 0.4 N / 25 mm or less, 0.3 N / 25 mm or less, or 0.2 N / 25 mm or less. From the viewpoint of preventing the reinforcing film from peeling off during storage and handling, the adhesive strength between the pressure-sensitive adhesive layer 2 and the adherend before photocuring is preferably 0.005 N / 25 mm or more, preferably 0.01 N / 25 mm or more. More preferably, 0.02 N / 25 mm or more is further preferable, and 0.03 N / 25 mm or more is particularly preferable.

The reinforcing film preferably has an adhesive force to the polyimide film within the above range when the pressure-sensitive adhesive layer is in a state before photo-curing. Flexible substrate materials are used in flexible display panels, flexible printed wiring boards (FPCs), devices that integrate display panels and wiring boards, etc., and are generally used from the viewpoint of heat resistance and dimensional stability. , Polyimide film is used. The reinforcing film in which the pressure-sensitive adhesive layer has the above-mentioned adhesive strength with respect to the polyimide film as a substrate can be easily peeled off before the photo-curing of the pressure-sensitive adhesive, and has excellent adhesive reliability after photo-curing.

Before the reinforcing film is attached, the adherend such as the polyimide film on the surface of the device may be activated for the purpose of cleaning or the like. Examples of the surface activation treatment include plasma treatment, corona treatment, glow discharge treatment and the like. In particular, atmospheric pressure plasma treatment is preferable because the treatment can be performed at atmospheric pressure and the activation effect is high.

When the surface activation treatment is applied to the adherend, the adhesive force between the pressure-sensitive adhesive layer 2 and the adherend before photo-curing tends to be higher than that when the surface activation treatment is not performed. If the adhesive force between the pressure-sensitive adhesive layer and the adherend before photo-curing becomes excessively large, rework may become difficult. Therefore, the adhesive strength between the surface-activated adherend and the pressure-sensitive adhesive layer before photo-curing is preferably 2N / 25 mm or less, more preferably 1.5N / 25mm or less, and even more preferably 1N / 25mm or less. The adhesive strength between the surface-activated adherend and the pressure-sensitive adhesive layer before photo-curing may be 0.7 N / 25 mm or less or 0.5 N / 25 mm or less. The adhesive strength between the surface-activated adherend and the adhesive layer before photo-curing is less than four times the adhesive strength between the non-surface-activated adherend and the adhesive layer before photo-curing. It is preferable, and more preferably 3 times or less. The adhesive strength between the surface-activated adherend and the adhesive layer before photo-curing is less than twice the adhesive strength between the non-surface-activated adherend and the adhesive layer before photo-curing. It may be 1.7 times or less or 1.5 times or less.

The adherend whose surface has been activated contains many active groups such as a hydroxy group, a carbonyl group, and a carboxyl group, and the adhesive force tends to increase due to the intermolecular interaction with the polar functional group of the base polymer. .. In particular, when the base polymer contains a nitrogen atom, it is considered that the adhesive strength tends to increase because the interaction between the unpaired electron of the nitrogen atom and the active group of the activated adherend is strong. .. In particular, when the adherend is polyimide, the activation treatment activates amic acid, terminal amino groups, carboxy groups (or carboxylic acid anhydride groups), etc., and mutually with the polar functional groups of the base polymer. It is considered that the strong action is also involved in the increase in the initial adhesive strength.

By using a cross-linking accelerator such as an organic metal, the increase in the initial adhesive force due to the surface activation treatment of the adherend tends to be suppressed, and in particular, the cross-linking functional group contained in one molecule of the cross-linking agent tends to be suppressed. The tendency is large when the number is large and the functional group density is high. When a cross-linking accelerator is used, the cross-linking functional group is activated to increase the reactivity. Therefore, the number of unreacted functional groups is reduced, the number of polymer chains crosslinked by one cross-linking agent is large, and a high-density cross-linked structure is likely to be formed, which is related to the suppression of the increase in the initial adhesive force. Conceivable.

For example, when the crosslink density is low, a photocuring agent (polyfunctional monomer) is likely to be present in the gaps between the polymer chains in the bulk portion of the pressure-sensitive adhesive layer, whereas when the crosslink density is high, the gaps between the polymer chains are likely to be present. It is considered that the photo-curing agent is unlikely to be present in the bulk portion because the amount is small (small), and the photo-curing agent is likely to be unevenly distributed in the vicinity of the interface in the pressure-sensitive adhesive layer before photo-curing. Therefore, even when the adherend is subjected to the surface activation treatment, it is considered that the increase in the initial adhesive force is suppressed because the interaction between the adherend and the base polymer at the adhesive interface is small.

Further, by using a cross-linking accelerator, the degree of cross-linking (gel fraction) is increased, so that unreacted (uncross-linked) hydroxy groups and carboxy groups are reduced. It is considered that the crosslinked structure portion is easily embedded inside the polymer, and the exposure of the oxygen atoms of the hydroxy group and the carboxy group reacted with the crosslinking agent to the surface is small, which also contributes to the suppression of the increase in the initial adhesive force. .. In particular, when the number of polymer chains crosslinked by one crosslinking agent is large, the interaction between the polar group of the base polymer and the active group of the adherend is small because the exposure of the crosslinked structure portion to the surface is small. It is considered that the increase in the initial adhesive force is suppressed.

(Storage modulus)
Pressure-sensitive adhesive layer 2 is preferably a shear storage modulus G _'i at 25 ° C. before photocuring is ^{1 × 10 4 ~1.2 × 10 5} Pa. The shear storage elastic modulus (hereinafter, simply referred to as “storage elastic modulus”) is based on the method described in JIS K7244-1 “Plastic-Dynamic Mechanical Properties Test Method” under the condition of a frequency of 1 Hz. It is obtained by reading the value at a predetermined temperature when measured at a heating rate of 5 ° C./min in the range of 50 to 150 ° C.

In a substance exhibiting viscoelasticity such as a pressure-sensitive adhesive, the storage elastic modulus G'is used as an index indicating the degree of hardness. The storage elastic modulus of the pressure-sensitive adhesive layer has a high correlation with the cohesive force, and the higher the cohesive force of the pressure-sensitive adhesive, the greater the anchoring force on the adherend tends to be. When the storage elastic modulus of the pressure-sensitive adhesive layer 2 before photo-curing is 1 × 10 ⁴ Pa or more, the pressure-sensitive adhesive has sufficient hardness and cohesive force, so that the adherend when the reinforcing film is peeled off from the adherend. It is difficult for adhesive residue to occur on the surface. Further, when the storage elastic modulus of the pressure-sensitive adhesive layer 2 is large, it is possible to prevent the pressure-sensitive adhesive from squeezing out from the end face of the reinforcing film. If photocuring adhesive layer before the second storage modulus 1.2 × 10 5 ^Pa or less, and a pressure-sensitive adhesive layer 2 is easily peeled off at the interface between the adherend, even when a rework , Cohesive breakage of the adhesive layer and adhesive residue on the surface of the adherend are unlikely to occur.

Enhance the rework of the reinforcing film, from the viewpoint of suppressing adhesive residue on the adherend at the time of reworking, the storage modulus G _'i at 25 ° C. before photocuring of the pressure-sensitive adhesive layer 2, 3 × 10 ⁴ to 1 × 10 ⁵ Pa is more preferable, and 4 × 10 ^{4 to} 9.5 × 10 ⁴ Pa is even more preferable.

<Photo-curing of adhesive layer>
After the reinforcing film is attached to the adherend, the pressure-sensitive adhesive layer 2 is photo-cured by irradiating the pressure-sensitive adhesive layer 2 with active light rays. Examples of the active light beam include ultraviolet rays, visible light, infrared rays, X-rays, α-rays, β-rays, and γ-rays. Ultraviolet rays are preferable as the active light rays because the curing of the pressure-sensitive adhesive layer in the stored state can be suppressed and the curing is easy. The irradiation intensity and irradiation time of the active light beam may be appropriately set according to the composition and thickness of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer 2 may be irradiated with the active light rays from either the film substrate 1 side or the adherend side, or the active light rays may be irradiated from both surfaces.

<Characteristics of adhesive layer after photo-curing>
(Adhesive strength)
From the viewpoint of adhesive reliability in practical use of the device, the adhesive strength between the pressure-sensitive adhesive layer 2 and the adherend after photocuring is preferably 2N / 25 mm or more, more preferably 3N / 25 mm or more, and 5N / 25 mm or more. More preferred. The adhesive strength between the reinforcing film and the adherend after the pressure-sensitive adhesive layer is photo-cured may be 6N / 25mm or more, 8N / 25mm or more, 10N / 25mm or more, 12N / 25mm or more, or 13N / 25mm or more. .. As for the reinforcing film, it is preferable that the adhesive layer after photocuring has an adhesive force in the above range with respect to the polyimide film. The adhesive strength between the pressure-sensitive adhesive layer 2 and the adherend after photo-curing is preferably 5 times or more, more preferably 8 times or more, and 10 times or more the adhesive strength between the pressure-sensitive adhesive layer 2 and the adherend before photo-curing. The above is more preferable. The adhesive strength between the adhesive layer and the adherend after photo-curing is 20 times or more, 30 times or more, 40 times or more, or 50 times or more the adhesive strength between the adhesive layer and the adherend before photo-curing. There may be.

As described above, the pressure-sensitive adhesive containing the base polymer in which the cross-linking structure is introduced by using the cross-linking agent and the cross-linking accelerator tends to suppress the increase in the initial adhesive force due to the surface activation treatment of the adherend. On the other hand, when the adherend is subjected to the surface activation treatment, the adhesive force between the pressure-sensitive adhesive layer 2 and the adherend after photocuring becomes larger than that when the surface activation treatment of the adherend is not performed. Tend. That is, when a reinforcing film having an adhesive layer having a predetermined composition is used, the adherend is subjected to a surface activation treatment such as plasma treatment to suppress an increase in initial adhesive force and ensure reworkability. At the same time, a device that achieves high adhesive strength after photo-curing and has excellent adhesive reliability of the reinforcing film can be obtained. In particular, when an organometallic cross-linking accelerator is used, the increase in the initial adhesive force when the adherend is surface-activated and the increase in the adhesive force after photocuring tend to be more remarkable.

(Storage modulus)
Pressure-sensitive adhesive layer 2 is preferably the storage modulus G _'f at 25 ° C. after photocuring is 1.0 × ¹⁰ 5 Pa or more. If the storage elastic modulus of the adhesive layer 2 after photocuring 1.0 × 10 5 ^Pa or more, improved adhesion to the adherend, high adhesion reliability is obtained with increasing cohesion .. On the other hand, when the storage elastic modulus is excessively large, the adhesive does not easily spread and the contact area with the adherend becomes small. Further, since the stress dispersibility of the pressure-sensitive adhesive is lowered, the peeling force tends to be easily propagated to the adhesive interface, and the adhesive force with the adherend tends to be lowered. Therefore, the storage modulus G _'f at 25 ° C. after light curing of the adhesive layer 2 is preferably 2 × ¹⁰ 6 Pa or less. The pressure-sensitive adhesive layer from the viewpoint of enhancing the adhesion reliability of the reinforcing film after photocuring, G _'f is more preferably ^{1.1 × 10 5 ~1.2 × 10 6} Pa, 1.2 × 10 5 ~1 × 10 ⁶ Pa is more preferable.

The ratio G _{'f /} G' _i of the storage modulus at 25 ° C. before and after light curing of the adhesive layer 2, preferably 2 or more. If G _'f is G' _i 2 times or more, a large increase in G 'by photocuring may both rework of previous photocuring and adhesion reliability after photocuring. G _'f / G' _i is more preferably 4 or more, more preferably 8 or more, particularly preferably 10 or more. The upper limit of G _{'f /} G' _i is not particularly limited, G if _{'f /} G' _i is excessively large, the pre photocurable G 'initial adhesion failure due to small, or G after photocuring' Is likely to lead to a decrease in adhesive reliability due to being excessively large. Therefore, G _'f / G' _i is preferably 100 or less, more preferably 40 or less, more preferably 30 or less, particularly preferably 25 or less.

The adherend after the reinforcing film is attached may be subjected to an autoclave treatment for the purpose of improving the affinity of the laminated interface of a plurality of laminated members, or a heat treatment such as thermocompression bonding for joining circuit members. When such a heat treatment is performed, it is preferable that the adhesive between the reinforcing film and the adherend does not flow from the end face.

From the viewpoint of suppressing the protrusion of the pressure-sensitive adhesive during high-temperature heating, the storage elastic modulus of the pressure-sensitive adhesive layer 2 at 100 ° C. after photocuring is preferably 5 × 10 ⁴ Pa or more, more preferably 8 × 10 ⁴ Pa or more. More preferably, 1 × 10 ⁵ Pa or more. From the viewpoint of preventing the adhesive from squeezing out during heating and preventing the adhesive strength from deteriorating during heating, the storage elastic modulus of the adhesive layer 2 after photocuring at 100 ° C is 60% of the storage elastic modulus at 50 ° C. The above is preferable, 65% or more is more preferable, 70% or more is further preferable, and 75% or more is particularly preferable.

By laminating the reinforcing film, appropriate rigidity is given to the work-in-process that is the adherend, and stress is relaxed and dispersed, so that various defects that may occur in the manufacturing process are suppressed and production efficiency is improved. And the yield can be improved. Further, even when the adherend is surface-activated, the reinforcing film can be easily peeled off from the adherend before the pressure-sensitive adhesive layer is photo-cured, resulting in poor lamination or bonding. In some cases, rework is easy. After the pressure-sensitive adhesive layer is photo-cured, it exhibits high adhesive strength to the adherend, the reinforcing film is difficult to peel off from the device surface, and the adhesive reliability is excellent.

The present invention will be further described with reference to Examples, but the present invention is not limited to these Examples.

[Comparative Example 1]
<Polymerization of base polymer>
95 parts by weight of butyl acrylate (BA) and 5 parts by weight of acrylic acid (AA) as monomers and azobisisobuty as a thermal polymerization initiator in a reaction vessel equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube. 0.2 parts by weight of ronitrile (AIBN) and 233 parts by weight of ethyl acetate as a solvent were added, nitrogen gas was allowed to flow, and nitrogen substitution was carried out for about 1 hour with stirring. Then, the mixture was heated to 60 ° C. and reacted for 7 hours to obtain a solution of an acrylic polymer having a weight average molecular weight of 600,000.

<Preparation of adhesive composition>
0.5 parts by weight of a tetrafunctional epoxy compound ("Tetrad C" manufactured by Mitsubishi Gas Chemicals) as a cross-linking agent in a solution of an acrylic polymer, and "NK ester A200" (polyethylene glycol #) manufactured by Shin-Nakamura Chemical Industries as a polyfunctional acrylic monomer. 200 (n = 4) diacrylate; 30 parts by weight of molecular weight 308, functional group equivalent 154 g / eq), and 0.1 part by weight of photopolymerization initiator (BASF "Irgacure 651") were added to make a pressure-sensitive adhesive composition. Was prepared.

<Application and cross-linking of adhesive composition>
The above pressure-sensitive adhesive composition was applied to a polyethylene terephthalate film having a thickness of 75 μm (“Lumirer S10” manufactured by Toray Industries, Inc.) that had not been surface-treated using a fountain roll so that the thickness after drying was 25 μm. After drying at 130 ° C. for 1 minute to remove the solvent, a release-treated surface of a separator (a polyethylene terephthalate film having a thickness of 25 μm with a silicone release-treated surface) was attached to the surface to which the adhesive was applied. Then, an aging treatment was carried out in an atmosphere of 25 ° C. for 4 days to allow cross-linking to proceed, a photocurable pressure-sensitive adhesive sheet was fixedly laminated on the film substrate, and a separator was temporarily attached thereto to obtain a reinforcing film.

[Examples 1 to 5]
In the preparation of the pressure-sensitive adhesive composition, in addition to the cross-linking agent, the polyfunctional acrylic monomer, and the photopolymerization initiator, the organometallic cross-linking accelerators of the types and amounts shown in Table 1 were added to the solution of the acrylic polymer. A reinforcing film was produced in the same manner as in Comparative Example 1 except that an organometallic cross-linking accelerator was added.

[Example 6]
In Example 6, in the preparation of the pressure-sensitive adhesive composition, in addition to a cross-linking agent, an organic metal cross-linking accelerator, a polyfunctional acrylic monomer, and a photopolymerization initiator in a solution of an acrylic polymer, a carboxy group-containing acrylic oligomer (Toa). Synthetic "ARUFON UC-3000"; weight average molecular weight: 10,000, glass transition temperature: 65 ° C., acid value: 74 mgKOH / g) 1 part by weight was added. Other than that, a reinforcing film was produced in the same manner as in Example 4.

[Measurement of adhesive strength to polyimide film]
<Adhesive strength before photo-curing>
A polyimide film having a thickness of 12.5 μm (“Kapton 50EN” manufactured by Toray DuPont) was attached to a glass plate via a double-sided adhesive tape (“No. 531” manufactured by Nitto Denko) to obtain a polyimide film substrate for measurement. The separator was peeled off from the surface of the reinforcing film cut out to a width of 25 mm and a length of 100 mm, and bonded to a polyimide film substrate for measurement using a hand roller to prepare a sample for adhesive force measurement (without plasma treatment).

While transporting the polyimide substrate for measurement at a transport speed of 3 m / min, plasma treatment was performed on the surface of the polyimide film under the condition of an electrode voltage of 160 V using a normal pressure plasma processor. A reinforcing film was attached to the polyimide film substrate for measurement after plasma treatment using a hand roller to prepare a sample for measurement of adhesive strength (with plasma treatment).

Using these test samples, the edge of the polyethylene terephthalate film of the reinforcing film was held by a chuck, and a 180 ° peel test of the reinforcing film was performed at a tensile speed of 300 mm / min to measure the peel strength. From the obtained results, the ratio of the adhesive force with the plasma treatment to the adhesive force without the plasma treatment (the rate of increase in the adhesive force with the plasma treatment) was calculated.

<Adhesive strength after photo-curing>
After the reinforcing film is attached to the polyimide film substrate (with and without plasma treatment), ultraviolet rays with an integrated light amount of 4000 mJ / cm ² are irradiated from the reinforcing film side (PET film side) using an LED light source having a wavelength of 365 nm. The pressure-sensitive adhesive layer was photocured. Using this test sample, the adhesive strength was measured by a 180 ° peel test in the same manner as described above.

Composition of adhesive for reinforcing films of Comparative Examples 1 and 1 to 6 (types of oligomer, polyfunctional monomer, photopolymerization initiator, cross-linking agent and cross-linking accelerator, and amount added to 100 parts by weight of base polymer), polyimide Table 1 shows the rate of increase in the adhesive force to the film and the adhesive force due to the plasma treatment (the ratio of the adhesive force to the "without plasma treatment" to the adhesive force with "plasma treatment") and the adhesive force after photocuring.

In Tables 1 and 2, "UC3000" is "ARUFON UC-3000" manufactured by Toagosei, "A200" is "NK ester A200" manufactured by Shin Nakamura Chemical Industry, and "APG700" is Shin Nakamura Chemical Industry. "NK Ester APG700" manufactured by BASF, "Irg651" is "Irgacure 651" manufactured by BASF, and "Irg184" is "Irgacure 184" manufactured by BASF. Details of the cross-linking accelerators in Tables 1 and 2 are as follows.
Fe: Tris (acetylacetone) iron (Nihon Kagaku Sangyo "Nasem Ferric")
Zr: Zirconium tetraacetylacetonate (manufactured by Tokyo Chemical Industry)
Ti: Titanium diisopropoxybis acetylacetonate (manufactured by Tokyo Chemical Industry)
Al: Aluminum Tris Acetylacetone (manufactured by Tokyo Chemical Industry)
Sn: Dioctyl tin dilaurate ("Envirizer OL-1" manufactured by Tokyo Fine Chemicals)

In both Comparative Example 1 and Examples 1 to 6, the initial adhesive force to the polyimide film substrate not subjected to plasma treatment was 0.2 N / 25 mm or less, and the polyimide film could be easily peeled off. Further, when the pressure-sensitive adhesive was photocured, the adhesive strength increased and the adhesive was firmly adhered to the polyimide film substrate.

In Comparative Example 1 in which the cross-linking accelerator was not added, the initial adhesive force to the polyimide film substrate after the plasma treatment exceeded 0.2 N / 25 mm, and the initial adhesive force to the polyimide film substrate not subjected to the plasma treatment was high. It had risen 1.4 times.

In Examples 1 to 5 to which the cross-linking accelerator was added, the initial adhesive force to the polyimide film substrate after the plasma treatment was lower than that in Comparative Example 1, and the increase in the initial adhesive force due to the plasma treatment was suppressed. In Example 6 in which the acrylic oligomer was added in addition to the acrylic base polymer, the increase in the initial adhesive force due to the plasma treatment was suppressed as in Example 4 in which the same iron-based cross-linking accelerator was used.

Focusing on the adhesive strength of the adhesive after photo-curing, in each of the examples, by adhering a reinforcing film to the polyimide substrate after plasma treatment and performing photo-curing, compared with the case where plasma treatment is not performed. The adhesive strength was increased, and the adhesive strength was equal to or higher than that of Comparative Example 1.

From the above results, by introducing a cross-linked structure into the base polymer using a cross-linking agent and a cross-linking accelerator, the initial adhesive force to the adherend subjected to activation treatment such as plasma treatment is low, and the reworkability is excellent. It can be seen that after the pressure-sensitive adhesive is photo-cured, higher adhesive strength can be achieved than when no cross-linking accelerator is used, and the adhesive reliability is excellent.

[Comparative Example 2]
<Polymerization of base polymer>
In a reaction vessel equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube, 63 parts by weight of 2-ethylhexyl acrylate (2EHA), 9 parts by weight of methyl methacrylate (MMA) and 13 parts by weight of hydroxyethyl acrylate (HEA) were used as monomers. 15 parts by weight, 15 parts by weight of N-vinylpyrrolidone (NVP), 0.2 parts by weight of AIBN as a thermal polymerization initiator, and 233 parts by weight of ethyl acetate as a solvent were added, nitrogen gas was flowed, and nitrogen was stirred for about 1 hour with stirring. Substitution was performed. Then, the mixture was heated to 60 ° C. and reacted for 7 hours to obtain a solution of an acrylic polymer having a weight average molecular weight of 1.2 million.

<Preparation of adhesive composition>
A 75% ethyl acetate solution of trimethylolpropane adduct of xylylene diisocyanate (“Takenate D110N” manufactured by Mitsui Chemicals, Inc.) as a cross-linking agent in an acrylic polymer solution with a solid content of 2.5 parts by weight, Shin-Nakamura as a polyfunctional acrylic monomer 30 parts by weight of "NK ester APG700" (polypropylene glycol # 700 (n = 12) diacrylate; molecular weight 808, functional group equivalent 404 g / eq) manufactured by Kagaku Kogyo, and 1 weight of photopolymerization initiator (BASF "Irgacure 184") Parts were added to prepare a pressure-sensitive adhesive composition.

<Application and cross-linking of adhesive composition>
In the same manner as in Comparative Example 1, the pressure-sensitive adhesive composition was applied, heat-dried and crosslinked to prepare a reinforcing film in which a photocurable pressure-sensitive adhesive sheet was fixedly laminated on a film substrate and a separator was temporarily attached thereto. did.

[Example 7 and Example 8]
In the preparation of the pressure-sensitive adhesive composition, in addition to the cross-linking agent, the polyfunctional acrylic monomer, and the photopolymerization initiator, the organometallic cross-linking accelerators of the types and amounts shown in Table 2 were added to the solution of the acrylic polymer. A reinforcing film was produced in the same manner as in Comparative Example 2 except that an organometallic cross-linking accelerator was added.

[Example 9]
In the preparation of the pressure-sensitive adhesive composition, BASF's "Irgacure 651" was used instead of BASF's "Irgacure 184" as the photopolymerization initiator. A reinforcing film was produced in the same manner as in Example 7 except for the above.

[Example 10]
In the preparation of the pressure-sensitive adhesive composition, 20 parts by weight of "NK Ester A200" manufactured by Shin Nakamura Chemical Industry Co., Ltd. was added instead of 30 parts by weight of "NK Ester APG700" manufactured by Shin Nakamura Chemical Industry Co., Ltd. as a polyfunctional acrylic monomer. A reinforcing film was produced in the same manner as in Example 7 except for the above.

[Measurement of adhesive strength to polyimide film]
A reinforcing film is attached to each of the polyimide film substrate not subjected to plasma treatment and the polyimide film substrate after plasma treatment, and the adhesive strength is measured by a peel test before and after photocuring the pressure-sensitive adhesive layer. did.

Table 2 shows the composition of the pressure-sensitive adhesives of the reinforcing films of Comparative Examples 2 and 7 to 10, the rate of increase in the adhesive force to the polyimide film and the adhesive force by plasma treatment, and the adhesive force after photocuring.

In Comparative Example 2 in which the cross-linking accelerator was not added, the initial adhesive force to the polyimide film substrate after the plasma treatment exceeded 2N / 25 mm, which was four times the initial adhesive force to the polyimide film substrate not subjected to the plasma treatment. As mentioned above, it was difficult to peel off the reinforcing film from the polyimide film substrate.

In Examples 7 and 8 to which the cross-linking accelerator was added, the initial adhesive force to the polyimide film substrate after the plasma treatment was 1 N / 25 mm or less, and the increase in the initial adhesive force was suppressed as compared with Comparative Example 2. In Example 9 in which the type of the photopolymerization initiator was changed and in Example 10 in which the type of the polyfunctional monomer was changed, the initial adhesive force by plasma treatment was similar to that in Example 7 using the same iron-based cross-linking accelerator. The rise of was suppressed.

Results of Comparative Example 1 and Examples 1 to 6 shown in Table 1 (an example in which a crosslinked structure was introduced into a copolymer polymer of butyl acrylate and acrylic acid by an epoxy-based crosslinking agent), and Comparative Example 2 and Examples shown in Table 2 From the results of Examples 7 to 10 (an example in which a crosslinked structure was introduced into a copolymer polymer of 2-ethylhexyl acrylate, methyl methacrylate, hydroxyethyl acrylate, and N-vinylpyrrolidone with an isocyanate-based crosslinking agent), types of base polymer and crosslinking agent However, it can be seen that the initial adhesive force to the activated adherend can be suppressed to a low level by using the cross-linking accelerator in addition to the cross-linking agent.

1 Film base material 2 Adhesive layer 10 Reinforcing film 5 Separator 20 Adhesive

Claims (16)

A film base material and an adhesive layer fixed and laminated on one main surface of the film base material are provided.
The pressure-sensitive adhesive layer comprises a photocurable composition containing a base polymer having a crosslinked structure, a photocuring agent, and a photopolymerization initiator.
A reinforcing film in which a base polymer having a crosslinked structure is formed by a crosslinking reaction of a composition containing a base polymer, a crosslinking agent, and a crosslinking accelerator. The reinforcing film according to claim 1, wherein the cross-linking accelerator is an organometallic compound. The base polymer contains at least one selected from the group consisting of a hydroxy group-containing monomer and a carboxy group-containing monomer as a monomer unit, and a cross-linked structure is introduced by a cross-linking agent bonded to the hydroxy group or the carboxy group. , The reinforcing film according to claim 1 or 2. The reinforcing film according to any one of claims 1 to 3, wherein the cross-linking agent is an isocyanate-based cross-linking agent or an epoxy-based cross-linking agent. The reinforcing film according to any one of claims 1 to 4, wherein the photocurable composition has a gel fraction of 60% or more. The reinforcing film according to any one of claims 1 to 5, which contains an acrylic polymer as the base polymer. The reinforcing film according to any one of claims 1 to 6, wherein the photocurable composition contains 10 to 50 parts by weight of the photocuring agent with respect to 100 parts by weight of the base polymer. The reinforcing film according to any one of claims 1 to 7, wherein the photocuring agent is a polyfunctional (meth) acrylate. The reinforcing film according to any one of claims 1 to 8, wherein the photocuring agent has a functional group equivalent of 100 to 500 g / eq. The reinforcing film according to any one of claims 1 to 9, wherein the adhesive force with the polyimide film before photo-curing the pressure-sensitive adhesive layer is 1 N / 25 mm or less. The method for producing a reinforcing film according to any one of claims 1 to 10.
A composition containing a base polymer, a cross-linking agent, a cross-linking accelerator, a photo-curing agent, and a photopolymerization initiator is applied in layers on a film substrate, and the reaction between the base polymer and the cross-linking agent causes the reaction. A method for producing a reinforcing film, in which a crosslinked structure is introduced into the base polymer to form an adhesive layer. The method for producing a reinforcing film according to any one of claims 1 to 10.
A composition containing a base polymer, a cross-linking agent, a cross-linking accelerator, a photo-curing agent, and a photopolymerization initiator is applied in layers, and the reaction between the base polymer and the cross-linking agent causes cross-linking to the base polymer. Introduce the structure to form the adhesive layer,
A method for producing a reinforcing film, in which the pressure-sensitive adhesive layer is transferred onto a film substrate. It is a manufacturing method of a device in which a reinforcing film is attached to the surface.
After the pressure-sensitive adhesive layer of the reinforcing film according to any one of claims 1 to 10 is temporarily attached to the surface of the adherend,
A method for manufacturing a device, which increases the adhesive force between the reinforcing film and the adherend by irradiating the pressure-sensitive adhesive layer with active light rays and photo-curing the pressure-sensitive adhesive layer. The method for manufacturing a device according to claim 13, wherein the surface activation treatment of the adherend is performed before the reinforcing film is temporarily attached. The method for manufacturing a device according to claim 14, wherein the surface activation treatment is a plasma treatment. It is a reinforcement method in which a reinforcing film is attached to the surface of the adherend.
After the surface activation treatment of the adherend, the pressure-sensitive adhesive layer of the reinforcing film according to any one of claims 1 to 10 is temporarily adhered to the surface of the adherend after the activation treatment.
A reinforcing method for increasing the adhesive force between the reinforcing film and the adherend by irradiating the pressure-sensitive adhesive layer with active light rays and photo-curing the pressure-sensitive adhesive layer.

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