KR20200001547A - Reinforcing film - Google Patents

Abstract

The present invention relates to a reinforcement film, which is easy to rework immediately after being bonded with an adherend, can be firmly adhered to the adherend, and can arbitrarily set the time until bonding force improves after being bonded with the adhered. The reinforcement film (10) comprises an adhesive layer (2) fixedly laminated on one main surface of a film base material (1), wherein the adhesive layer consists of a photo-curable composition comprising a base polymer, a photo-curing agent, a photo-radical initiator and an antioxidant. In addition, the photo-curable composition comprises: 10 to 50 parts by weight of the photo-curing agent; 0.01 to 1 parts by weight of the photo-radical initiator; and 0.01 to 2 parts by weight of the antioxidant with respect to 100 parts by weight of the base polymer.

Description

Reinforcement film {REINFORCING FILM}

TECHNICAL FIELD This invention relates to the reinforcement film stuck to the device surface.

The adhesive film may be stuck to the surface of optical devices, such as a display, and an electronic device for the purpose of surface protection, imparting impact resistance, etc. In such an adhesive film, an adhesive layer is fixedly laminated on the main surface of a film base material normally, and is bonded to a device surface through this adhesive layer.

Damage to or damage to the adherend can be suppressed by adhering the adhesive film to the surface of the device or the device component in the state before use, such as assembling, processing or transporting the device. As described above, the adhesive film to be temporarily attached for the purpose of temporary protection of the surface is required to be easily peeled from the adherend and that no glue residue on the adherend is generated.

In addition to assembling, processing, transporting, etc. of a device, patent document 1 discloses the adhesive film used in the state stuck to the device surface also at the time of use of a device. Such an adhesive film has the function of reinforcing a device by disperse | distributing an impact to a device, providing rigidity to a flexible device, etc. in addition to surface protection.

When bonding an adhesive film to a to-be-adhered body, bonding defects, such as mixing of a bubble and the shift | offset | difference of a sticking position, may arise. When the bonding failure occurs, the work (rework) for peeling the adhesive film from the adherend and bonding the other adhesive film is performed. Since the adhesive film used as a process material is designed on the premise of peeling from a to-be-adhered body, rework is easy. On the other hand, since reinforcing films on the premise of permanent adhesion are generally firmly adhered to the surface of the device without assuming that they are peeled off from the device, rework is difficult.

Patent document 2 discloses an adhesive sheet (adhesive layer) designed to have low adhesiveness immediately after bonding with an adherend and to increase adhesive strength over time. The adhesive film in which such an adhesive layer is fixedly laminated on a film substrate is easily peeled from the adherend immediately after bonding with the adherend, and firmly adheres to the adherend after a predetermined time has elapsed. It can be used as a reinforcing film having.

Japanese Laid-Open Patent Publication No. 2017-132977 WO 2015/163115 pamphlet

It is difficult to say that the reinforcing film whose adhesion with the adherend changes over time is sufficiently flexible to the lead time of the process. For example, the reinforcement film provided with the adhesive layer which an adhesive force rises with time needs to test and rework a bonded state within the predetermined time until bonding force rises after bonding with a to-be-adhered body. Moreover, after bonding a reinforcement film on the whole surface of a device or a device component, when processing, such as removing a reinforcement film in some area | region, it is necessary to process in the period until adhesive force rises.

In view of the above, in the present invention, the rework is easy immediately after bonding to the adherend, and the time from bonding to the adherend can be arbitrarily set, and the adhesion strength is improved by improving the adhesion. An object of the present invention is to provide a reinforcing film that can be firmly bonded.

The reinforcement film of this invention is equipped with the adhesive layer fixedly laminated on one main surface of a film base material. The pressure-sensitive adhesive layer consists of a photocurable composition containing a base polymer, a photocuring agent, an optical radical initiator and an antioxidant. It is preferable that the photocurable composition which comprises an adhesive layer contains 10-50 weight part of photocuring agents, 0.01-1 weight part of optical radical initiators, and 0.01-2 weight part of antioxidant with respect to 100 weight part of base polymers. As for content of antioxidant in a photocurable composition, 0.2-5 times of content of an optical radical initiator is preferable.

From the viewpoint of suppressing the generation of radicals from the optical radical initiator by light such as a fluorescent lamp, the optical radical initiator preferably has an absorption maximum in the range of 310 nm to 355 nm and does not exhibit an absorption maximum at a longer wavelength than 360 nm. do.

As a base polymer of an adhesive layer, an acryl-type polymer is used, for example. It is preferable that an acrylic polymer contains 5-50 weight% of monomer components whose glass transition temperature of a homopolymer is 40 degreeC or more.

It is preferable that the crosslinked structure is introduce | transduced into the base polymer of an adhesive layer. For example, a base polymer contains a hydroxyl group containing monomer and / or a carboxyl group containing monomer as a monomer unit, and a crosslinking structure is introduce | transduced when crosslinking agents, such as a polyfunctional isocyanate compound and a polyfunctional epoxy compound, couple | bond with these functional groups.

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

It is preferable that the reinforcement film is 0.005-5 N / 25mm of adhesive force with a polyimide film. After photocuring an adhesive layer, it is preferable that the adhesive force of a reinforcement film and a polyimide film is 6N / 25mm or more.

In the reinforcing film of the present invention, the adhesive layer is made of a photocurable composition, and the adhesive force with the adherend is increased by photocuring the adhesive layer after adhesion with the adherend. Since the adhesive force with the adherend is small before the photocuring, the rework is easy, and after the photocuring, the rework is high, which contributes to the reinforcement of the device and the improvement of the reliability. The photocurable adhesive can arbitrarily set the timing of hardening after bonding with a to-be-adhered body. Moreover, when an adhesive composition contains antioxidant in addition to a base polymer, a photocuring agent, and an optical radical initiator, the photocuring reaction resulting from light, such as a fluorescent lamp, in a storage environment is suppressed. Therefore, long term storage of a reinforcement film is possible in the state before bonding with a to-be-adhered body, after bonding with an to-be-adhered body, and before photocuring. Therefore, the reinforcement film of this invention has the advantage that it can respond flexibly to the lead time of a process.

1 is a cross-sectional view showing the laminated structure of a reinforcement film.
It is sectional drawing which shows the laminated structure of a reinforcement film.
It is sectional drawing which shows the device on which the reinforcement film was stuck.
4 is a graph showing the measurement results of the amount of radicals generated by light irradiation at cryogenic temperatures.

1 is a cross-sectional view showing an embodiment of a reinforcing film. The reinforcement film 10 is provided with the adhesive layer 2 on one main surface of the film base material 1. The adhesive layer 2 is fixedly laminated on one main surface of the base film 1. The adhesive layer 2 is a photocurable adhesive which consists of a photocurable composition, hardens | cures by irradiation of active light, such as an ultraviolet-ray, and the adhesive force with a to-be-adhered body increases.

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

The reinforcement film 10 is affixed on the surface of the device 20 by peeling and removing the separator 5 from the surface of the adhesive layer 2 and bonding the exposed surface of the adhesive layer 2 to the surface of the device 20. . In this state, the adhesive layer 2 is before photocuring, and the reinforcement film 10 (adhesive layer 2) is stuck on the device 20. By photocuring the adhesive layer 2, the adhesive force in the interface of the device 20 and the adhesive layer 2 rises, and the device 20 and the reinforcement film 10 adhere | attach.

 "Fixing" is a state in which two laminated layers are firmly adhered and peeling at the interface between them is impossible or difficult. "Adhesion" is a state in which the adhesive force between two laminated layers is small and can be easily peeled off at both interfaces.

In the reinforcement film shown in FIG. 2, the film base material 1 and the adhesive layer 2 are fixed, and the separator 5 is stuck to the 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. . An adhesive does not remain on the separator 5 after peeling.

The device in which the reinforcement film 10 shown in FIG. 3 is stuck is in the state which the device 20 and the adhesive layer 2 adhered to 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. do. Since no adhesive remains on the device 20, rework is easy. After photocuring the adhesive layer 2, since the adhesive force between the adhesive layer 2 and the device 20 increases, it is difficult to peel the film 1 from the device 20. Cohesive failure of 2) may occur.

[Film base material]

As the film base material 1, a plastic film is used. In order to fix the film base material 1 and the adhesive layer 2, it is preferable that the adhesive layer 2 laying surface of the film base material 1 does not perform the mold release process.

The thickness of a film base material is about 4-500 micrometers, for example. From the viewpoint of reinforcing the device by stiffening, impact relaxation, or the like, the thickness of the film base material 1 is preferably 20 µm or more, more preferably 30 µm or more, and even more preferably 45 µm or more. From the viewpoint of making the reinforcement film flexible and improving handling properties, the thickness of the film base material 1 is preferably 300 µm or less, and more preferably 200 µm or less. From the viewpoint of achieving both mechanical strength and flexibility, the compressive strength of the film base material 1 is preferably 100 to 3000 kg / cm 2, more preferably 200 to 2900 kg / cm 2, and even more preferably 300 to 2800 kg / cm 2. And, 400-2700 kg / cm <2> is especially preferable.

As a plastic material which comprises the film base material 1, polyester resin, polyolefin resin, cyclic polyolefin resin, polyamide resin, polyimide resin, etc. are mentioned. In reinforcement films for optical devices, such as a display, it is preferable that the film base material 1 is a transparent film. In addition, when photocuring the adhesive layer 2 by irradiating actinic light from the film base material 1 side, it is preferable that the film base material 1 has transparency with respect to the actinic light used for hardening of an adhesive layer. . In view of having mechanical strength and transparency, polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate are preferably used. When irradiating actinic light from the to-be-adhered body side, the to-be-adhered body should just have transparency with respect to actinic light, and the film base material 1 does not need to be transparent with respect to actinic light.

On the surface of the film base material 1, functional coatings, such as an easily bonding layer, an easily slid layer, a mold release layer, an antistatic layer, a hard-coat layer, and an antireflection layer, may be formed. In addition, as mentioned above, in order to fix the film base material 1 and the adhesive layer 2, it is preferable that the release layer is not formed in the adhesive layer 2 laying surface of the film base material 1.

[Adhesive Layer]

The adhesive layer 2 fixedly laminated on the film base material 1 is a photocurable composition containing a base polymer, a photocuring agent, and an optical radical initiator. When a reinforcement film is used for optical devices, such as a display, 80% or more of the total light transmittance of the adhesive layer 2 is preferable, 85% or more is more preferable, 90% or more is more preferable. 2% or less is preferable, as for the haze of the adhesive layer 2, 1% or less is more preferable, 0.7% or less is more preferable, 0.5% or less is especially preferable.

Since the adhesive layer 2 has small adhesive force with a to-be-adhered body before photocuring, rework is easy. When the pressure-sensitive adhesive layer 2 is irradiated with active light such as ultraviolet rays, radicals are generated from the photoradical initiator, and the adhesion to the adherend is improved by the radical polymerization reaction (photocuring) of the photocuring agent. Therefore, when using the device, the reinforcing film is less likely to peel off from the surface of the device, and the adhesion reliability is excellent.

The photocurable adhesive advances hardening by irradiation, such as an ultraviolet-ray. Therefore, the adhesive layer 2 which consists of a photocurable adhesive composition has the advantage that the timing of hardening can be set arbitrarily and can respond flexibly to the lead time of a process, etc. On the other hand, in the state before use of a reinforcement film, or after bonding a reinforcement film with a to-be-adhered body, and before photocuring, radical may generate | occur | produce from an optical radical initiator by the light from fluorescent lamp etc. in a storage environment.

Since the amount of radicals generated by light such as a fluorescent lamp is sufficiently small compared to the amount of radicals generated by ultraviolet irradiation at the time of photocuring, the photocuring reaction hardly proceeds even when left under a fluorescent lamp for a short time. However, when the reinforcing film is stored under a fluorescent lamp for a long time, the cumulative amount of radicals generated from the photoradical initiator may increase due to the light of the fluorescent lamp and the influence may not be neglected. Specifically, polymerization of a photocuring agent advances with the radical produced | generated from an optical radical initiator, and the adhesive force of an adhesive rises, and peeling of a reinforcement film from an adherend may become difficult. Moreover, photocuring may not progress and adhesive force may not rise even if it irradiates with ultraviolet-ray, due to deactivation of the radical photoinitiator by long term storage.

The reinforcing film of this invention contains the antioxidant which the photocurable composition which comprises the adhesive layer 2 is added to a base polymer, a photocuring agent, and a photoradical initiator. By using an optical radical initiator and an antioxidant together, even if the reinforcement film is stored for a long time under fluorescent lamps, the change in the adhesive force is small, and it is possible to appropriately increase the adhesive force during light irradiation.

<Composition of adhesive>

Hereinafter, preferred forms of each of the base polymer, the photocuring agent, the photoradical initiator and the antioxidant constituting the photocurable composition will be described in order.

(Base polymer)

The base polymer is the main component of the pressure-sensitive adhesive composition. The kind of base polymer is not specifically limited, What is necessary is just to select an acryl-type polymer, a silicone type polymer, a urethane type polymer, a rubber type polymer suitably. In particular, the adhesive composition preferably contains an acrylic polymer as the base polymer from the viewpoint of excellent optical transparency and adhesiveness and easy control of adhesiveness, and preferably 50% by weight or more of the adhesive composition is an acrylic polymer.

As an acryl-type polymer, what contains a (meth) acrylic-acid alkylester as a main monomer component is used preferably. In addition, in this specification, "(meth) acryl" means acrylic and / or methacryl.

As the (meth) acrylic acid alkyl ester, a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of an alkyl group is preferably used. The alkyl group of the (meth) acrylic acid alkyl ester may be linear or may have a branch. Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, ( Pentyl methacrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic acid Isooctyl, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, isodetride (meth) acrylate Thread, Tetradecyl (meth) acrylate, Isotetradecyl (meth) acrylate, Pentadecyl (meth) acrylate, Cetyl (meth) acrylate, Heptadecyl (meth) acrylate, Octadecyl (meth) acrylate, Isoocta (meth) acrylate Decyl, (met) And the like can be mentioned acrylic acid nonadecyl (meth) acrylate, aralkyl.

40 weight% or more is preferable with respect to the monomer component whole quantity which comprises a base polymer, as for content of the (meth) acrylic-acid alkylester, 50 weight% or more is more preferable, 55 weight% or more is more preferable.

It is preferable that an acryl-type base polymer contains the monomer component which has a crosslinkable functional group as a copolymerization component. Examples of the monomer having a crosslinkable functional group include a hydroxy group-containing monomer and a carboxyl group-containing monomer. The hydroxyl group and carboxy group of a base polymer become a reaction point with the crosslinking agent mentioned later. For example, when using an isocyanate crosslinking agent, it is preferable to contain a hydroxyl group containing monomer as a copolymerization component of a base polymer. When using an epoxy type crosslinking agent, it is preferable to contain a carboxy group containing monomer as a copolymerization component of a base polymer. By introducing a crosslinked structure into the base polymer, the cohesion 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.

As the hydroxyl group-containing monomer, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 8- (meth) acrylic acid Hydroxyoctyl, (meth) acrylic acid 10-hydroxydecyl, (meth) acrylic acid 12-hydroxylauryl, (meth) acrylic acid 4- (hydroxymethyl) cyclohexyl) methyl, and the like. As a carboxyl group-containing monomer, (meth) acrylic acid, 2-carboxyethyl (meth) acrylic acid, carboxypentyl (meth) acrylic acid carboxypentyl, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. are mentioned.

It is preferable that the total amount of the hydroxy group-containing monomer and the carboxyl group-containing monomer with respect to the total amount of the constituent monomer components of the acrylic base polymer is 1 to 30% by weight, more preferably 3 to 25% by weight, still more preferably 5 to 20% by weight. Do. In particular, it is preferable that content of the (meth) acrylic acid ester containing a hydroxyl group is the said range.

The acrylic base polymer is a constituent monomer component such as N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxa It is preferable to contain nitrogen containing monomers, such as a sol, vinyl morpholine, N-acryloyl morpholine, N-vinylcarboxylic acid amides, and N-vinyl caprolactam. Acrylic base polymers containing nitrogen-containing monomer components contribute to the prevention of localized whitening, local swelling, and peeling of the pressure-sensitive adhesive layer because they exhibit moderate water absorption in a moist heat environment and local absorption of the pressure-sensitive adhesive is suppressed. .

It is preferable that content of a nitrogen-containing monomer with respect to constituent monomer component whole quantity is 1-30 weight%, it is more preferable that it is 3-25 weight%, and, as for an acrylic base polymer, it is still more preferable that it is 5-20 weight%. The acrylic base polymer preferably contains N-vinylpyrrolidone as the nitrogen-containing monomer in the above range.

When the acrylic base polymer contains both a hydroxy group-containing monomer and a nitrogen-containing monomer as monomer components, the cohesion force and transparency of the pressure-sensitive adhesive tend to be increased. It is preferable that the total amount of the hydroxy group-containing monomer and the nitrogen-containing monomer with respect to the total amount of the constituent monomer components of the acrylic base polymer is 5 to 50% by weight, more preferably 10 to 40% by weight, still more preferably 15 to 35% by weight. Do.

The acrylic base polymer may contain the monomer component of that excepting the above. The acrylic base polymer may contain, for example, a cyano group-containing monomer, a vinyl ester monomer, an aromatic vinyl monomer, an epoxy group-containing monomer, a vinyl ether monomer, a sulfo group-containing monomer, a phosphoric acid group-containing monomer, an acid anhydride group-containing monomer, and the like. .

The adhesive properties of the pressure sensitive adhesive before photocuring are likely to depend on the constituents and molecular weight of the base polymer. The larger the molecular weight of the base polymer, the harder the adhesive is. 100,000-5 million are preferable, as for the weight average molecular weight of an acrylic base polymer, 300,000-3 million are more preferable, and 500,000-2 million are still more preferable. In addition, when a crosslinked structure is introduce | transduced into a base polymer, the molecular weight of a base polymer refers to the molecular weight before introduction of a crosslinked structure.

The higher the content of the high Tg monomer component in the constituent components of the base polymer, the more the adhesive tends to be hard. In addition, a high Tg monomer means the monomer with high glass transition temperature (Tg) of a homopolymer. As a monomer whose Tg of a homopolymer is 40 degreeC or more, dicyclopentanyl methacrylate (Tg: 175 degreeC), dicyclopentanyl acrylate (Tg: 120 degreeC), isobornyl methacrylate (Tg: 173 degreeC), isobornyl acryl (Tg: 97 ° C), methyl methacrylate (Tg: 105 ° C), 1-adamantyl methacrylate (Tg: 250 ° C), 1-adamantyl acrylate (Tg: 153 ° C), and the like ( Meth) acrylic monomers; Acryloyl morpholine (Tg: 145 ° C), dimethyl acrylamide (Tg: 119 ° C), diethyl acrylamide (Tg: 81 ° C), methylaminopropyl acrylamide (Tg: 134 ° C), isopropyl acrylamide ( Amide group-containing vinyl monomers such as Tg: 134 ° C) and hydroxyethylacrylamide (Tg: 98 ° C); N-vinylpyrrolidone (Tg: 54 degreeC) etc. are mentioned.

It is preferable that content of the monomer whose Tg of a homopolymer is 40 degreeC or more is 5-50 weight% with respect to the constituent monomer component whole quantity, and, as for an acryl-type base polymer, it is more preferable that it is 10-40 weight%. In order to form the adhesive layer which has moderate hardness and excellent reworkability, it is preferable to include the monomer component whose Tg of a homopolymer is 80 degreeC or more as a monomer component of a base polymer, and the monomer component whose Tg of a homopolymer is 100 degreeC or more is used. It is more preferable to include. It is preferable that content of the monomer whose Tg of a homopolymer is 100 degreeC or more with respect to whole quantity of a constituent monomer component of an acrylic base polymer is 0.1 weight% or more, It is more preferable that it is 0.5 weight% or more, It is further more preferable that it is 1 weight% or more, 3 weight It is especially preferable that it is% or more. In particular, it is preferable that content of methyl methacrylate is the said range.

The acrylic polymer as a base polymer is obtained by superposing | polymerizing the said monomer component by various well-known methods, such as solution polymerization, emulsion polymerization, and bulk polymerization. The solution polymerization method is preferable from a viewpoint of the balance of properties, such as adhesive force and holding force of an adhesive, cost, etc. Ethyl acetate, toluene, etc. are used as a solvent of solution polymerization. The solution concentration is usually about 20 to 80% by weight. As a polymerization initiator used for solution polymerization, various well-known things, such as an azo system and a peroxide type, can be used. In order to adjust molecular weight, a chain transfer agent may be used. Reaction temperature is about 50-80 degreeC normally, and reaction time is about 1 to 8 hours normally.

(Bridge)

From the standpoint of having a cohesive force suitable for the pressure-sensitive adhesive, it is preferable that a crosslinked structure be introduced into the base polymer. For example, a crosslinking structure is introduce | transduced by adding a crosslinking agent to the solution after superposition | polymerization and heating as needed. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a carbodiimide crosslinking agent, and a metal chelate crosslinking agent. These crosslinkers react with functional groups such as hydroxy groups and carboxyl groups introduced into the base polymer to form a crosslinked structure. An isocyanate type crosslinking agent and an epoxy type crosslinking agent are preferable at the point which is highly reactive with the hydroxyl group and carboxy group of a base polymer, and is easy to introduce | transduce a crosslinked structure.

As an isocyanate type crosslinking agent, the polyisocyanate which has two or more isocyanate groups in 1 molecule is used. As an isocyanate type crosslinking agent, For example, lower aliphatic polyisocyanates, such as butylene diisocyanate and hexamethylene diisocyanate; Alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; Aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; Trimethylolpropane / tolylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, 'Colonate L'), Trimethylolpropane / hexamethylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, 'Colonate HL') And isocyanates such as trimethylolpropane adducts of xylylene diisocyanate (e.g., Mitsui Chemicals, 'Takenate D110N', isocyanurates of hexamethylene diisocyanate (e.g., Tosoh Corporation, 'Colonate HX') Additives, etc. are mentioned.

As an epoxy type crosslinking agent, the polyfunctional epoxy compound which has two or more epoxy groups in 1 molecule is used. The glycidyl group may be an epoxy group of an epoxy-type crosslinking agent. Examples of the epoxy crosslinking agent include N, N, N ', N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis (N, N-diglycidylaminomethyl) cyclo Hexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol Diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropanepolyglycol Cydyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcin diglycidyl ether, bisphenol-S -Diglycidyl ether, etc. can be mentioned. . As an epoxy type crosslinking agent, you may use commercial items, such as "Denacol" by Nagase Chemtex, "Tetrad X" and "Tetrad C" by Mitsubishi Gas Chemical.

What is necessary is just to adjust the usage-amount of a crosslinking agent suitably according to the composition, molecular weight, etc. of a base polymer. The usage-amount of a crosslinking agent is about 0.1-10 weight part with respect to 100 weight part of base polymers, Preferably it is 0.3-7 weight part, More preferably, it is 0.5-5 weight part, More preferably, it is 1-4 weight part. In addition, the value obtained by dividing the amount of use of the crosslinking agent (parts by weight) with respect to 100 parts by weight of the base polymer by the functional group equivalent (g / eq) of the crosslinking agent is preferably 0.00015 to 0.11, more preferably 0.001 to 0.077, and still more preferably 0.003 to 0.055. It is preferable and 0.0045-0.044 are especially preferable. By increasing the amount of the crosslinking agent to be larger than the general acrylic optically transparent adhesive and having the hardness suitable for the adhesive, there is a tendency that the adhesive residue on the adherend during rework is reduced and the rework property is improved.

In order to promote formation of the crosslinked structure, a crosslinking catalyst may be used. For example, as a crosslinking catalyst of an isocyanate crosslinking agent, a metal crosslinking catalyst such as tetra-n-butyl titanate, tetraisopropyl titanate, ferric nasemu, butyltin oxide, dioctyltin dilaurate (particularly a tin crosslinking catalyst) ), And the like. The usage-amount of a crosslinking catalyst is generally 0.05 weight part or less with respect to 100 weight part of base polymers.

 (Photocuring agent)

The adhesive composition which comprises the adhesive layer 2 contains a photocuring agent in addition to a base polymer. When the adhesive layer 2 which consists of a photocurable adhesive composition is photocured after bonding with a to-be-adhered body, the adhesive force with a to-be-adhered body improves.

As a photocuring agent, the compound which has 2 or more ethylenically unsaturated bond in 1 molecule is preferable. Moreover, the compound in which the photocuring agent shows compatibility with a base polymer is preferable. In view of the proper compatibility with the base polymer, the photocuring agent is preferably a liquid at room temperature. The photocuring agent is compatible with the base polymer and uniformly dispersed in the composition, thereby ensuring a contact area with the adherend and providing a highly transparent adhesive layer 2. Moreover, since a base polymer and a photocuring agent show suitable compatibility, a crosslinked structure is easy to be introduce | transduced uniformly in the adhesive layer 2 after photocuring, and there exists a tendency for the adhesive force with a to-be-adhered body to raise suitably.

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, Hansen solubility parameters, and the smaller the difference between the solubility parameters of the base polymer and the photocuring agent, the higher the compatibility.

It is preferable to use polyfunctional (meth) acrylate as a photocuring agent from the point of compatibility with an acryl-type base polymer. As polyfunctional (meth) acrylate, polyethyleneglycol di (meth) acrylate, polypropylene glycoldi (meth) acrylate, polytetramethylene glycoldi (meth) acrylate, bisphenol A ethylene oxide modified di (meth) acrylate, Bisphenol A propylene oxide modified di (meth) acrylate, alkanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate, pentaerythritol tree (Meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, penta Erythritol tetra (meth) acrylate, dipentaerythritol poly (meth) acrylate, dipentaerythritol hexa (meth ) Acrylate, neopentyl glycol di (meth) acrylate, glycerin di (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, butadiene (meth) acrylate, isoprene (meth) acrylate, etc. Can be mentioned. Among these, polyethyleneglycol di (meth) acrylate or polypropylene glycoldi (meth) acrylate is preferable, and polyethyleneglycol di (meth) acrylate is preferable at the point which is excellent in compatibility with an acrylic base polymer.

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. 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, still more preferably 500 or less, and particularly preferably 400 or less.

In the pressure-sensitive adhesive layer 2 before photocuring, the property of the base polymer is a major dominant factor of adhesion. Therefore, if the base polymer of an adhesive composition is the same, even if the kind of photocuring agent is different, the difference of the adhesive characteristic of the adhesive layer before photocuring is small. The kind and content of a photocuring agent mainly affect the adhesive force of the adhesive layer after photocuring. The smaller the functional group equivalent (i.e., the larger the number of functional groups per unit molecular weight), the higher the content of the photocuring agent can make the difference in adhesive force before and after photocuring.

From the standpoint of high compatibility with the base polymer and improving the adhesion after photocuring, the functional group equivalent (g / eq) of the photocuring agent is preferably 500 or less, more preferably 400 or less, still more preferably 300 or less. , 200 or less are particularly preferable. On the other hand, when the functional group equivalent of a photocuring agent is too small, the crosslinking point density of the adhesive layer after photocuring may become high, and adhesiveness may fall. Therefore, 80 or more are preferable, as for the functional group equivalent of a photocuring agent, 100 or more are more preferable, and 130 or more are more preferable.

In the combination of an acrylic base polymer and a polyfunctional acrylate photocuring agent, when the functional group equivalent of a photocuring agent is small, interaction of a base polymer and a photocuring agent is strong, and there exists a tendency for initial stage adhesive force to rise. In the use of the present invention, excessive increase in the initial adhesive force may lead to a decrease in reworkability. It is preferable that the functional group equivalent of a photocuring agent exists in the said range also from a viewpoint of maintaining the adhesive force of the adhesive layer 2 before photocuring and a to-be-adhered body in an appropriate range.

As for content of the photocuring agent in an adhesive composition, 1-50 weight part is preferable with respect to 100 weight part of base polymers. By making the compounding quantity of a photocuring agent into the said range, the adhesiveness of the adhesive layer after photocuring and a to-be-adhered body can be adjusted to an appropriate range. 15-45 weight part is more preferable with respect to 100 weight part of base polymers, and, as for content of a photocuring agent, 20-40 weight part is more preferable.

(Optical radical initiator)

The photoradical initiator generates radicals by irradiation of actinic rays, and promotes the radical polymerization reaction of the photocuring agent by radical transfer from the photoradical initiator to the photocuring agent. As an optical radical initiator (optical radical generator), it is preferable to generate radicals by irradiation of visible light or ultraviolet rays having a shorter wavelength than the wavelength of 450 nm, and hydroxyketones, benzyl dimethyl ketals, amino ketones, acylphosphine oxides, and benzophene. Non-streams, trichloromethyl group containing triazine derivative, etc. are mentioned. An optical radical initiator may be used independently and may be used in mixture of 2 or more type.

When transparency is required for the pressure-sensitive adhesive layer 2, it is preferable that the optical radical initiator has a lower sensitivity to light (visible light) having a longer wavelength than 400 nm, for example, an absorption coefficient at wavelength 405 nm of 1 × 10 ² [mLg ⁻¹ cm ^-1 ] or less radical photoinitiator is used preferably. Moreover, when the optical radical initiator with a small sensitivity of visible light is used, the storage stability of a reinforcement film can be improved because the amount of production of optical radicals resulting from external light in a storage environment is small.

From the viewpoint of improving the storage stability of the reinforcing film, it is preferable to use an optical radical initiator that does not exhibit an absorption maximum at a longer wavelength than 360 nm. The photoradical initiator, which exhibits an absorption maximum at a longer wavelength than 360 nm, absorbs ultraviolet rays (mainly 365 nm and 405 nm mercury bright lines) from fluorescent lamps and easily generates optical radicals. When the maximum wavelength of light absorption of an optical radical initiator is 360 nm or less, the amount of generation | occurrence | production of radicals resulting from light in storage environments, such as a fluorescent lamp, is small. Therefore, even when the reinforcing film is exposed for a long time under fluorescent lamps, the effective concentration of the optical radical initiator can be maintained high. In addition, since a small amount of radicals generated due to light in a storage environment such as a fluorescent lamp is trapped by an antioxidant, photopolymerization in the storage environment is suppressed.

In order that the storage stability is high and the adhesive force with a to-be-adhered body can be improved by light irradiation after long-term storage, it is preferable that the maximum radical of light absorption is 355 nm or less in the optical radical initiator contained in an adhesive layer. On the other hand, in order to improve the photocuring efficiency by ultraviolet irradiation, it is preferable that an optical radical initiator has a light absorption maximum in long wavelength rather than 310 nm. As mentioned above, in order to improve the storage stability of a reinforcement film, it is preferable that the optical radical initiator contained in the adhesive layer 2 does not have an absorption maximum in long wavelength rather than a wavelength of 360 nm, and has an absorption maximum in the range of wavelength 310-355 nm. Do. As for the absorption maximum wavelength of an optical radical initiator, 315-350 nm is more preferable, and 320-340 nm is further more preferable.

0.01-1 weight part is preferable with respect to 100 weight part of base polymers, as for content of the photoradical initiator in the adhesive layer 2, 0.02-0.7 weight part is more preferable, 0.03-0.5 weight part is more preferable. The content of the optical radical initiator in the pressure-sensitive adhesive layer 2 is preferably 0.005 to 0.5 parts by weight, more preferably 0.01 to 0.4 parts by weight, still more preferably 0.02 to 0.3 parts by weight with respect to 100 parts by weight of the photocuring agent. When content of the photoradical initiator in an adhesive layer is too small, a photocuring reaction may not fully advance even if it irradiates an ultraviolet-ray. When the content of the optical radical initiator is excessively large, even when the antioxidant is used in combination, the photocuring reaction proceeds in the storage environment, the adhesive strength with the adherend increases, and the rework of the reinforcing film may be difficult.

(Antioxidant)

Antioxidant has the effect | action which suppresses photocuring reaction in the storage environment of a reinforcement film. In a composition containing an antioxidant in addition to the photoradical initiator, even when a small amount of photoradical is generated from the photoradical initiator by light from a fluorescent lamp or the like, since the antioxidant traps radicals and generates stable radicals, Radical migration is suppressed. Therefore, photocuring (radical polymerization reaction of a photocuring agent) by the light from a fluorescent lamp etc. is suppressed.

Examples of the antioxidants include amine antioxidants, sulfur antioxidants, phosphorus antioxidants, and phenolic antioxidants.

Examples of the sulfur-based antioxidant include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, and the like. Triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite etc. are mentioned as a phosphorus antioxidant.

As an amine antioxidant, Monoalkyl diphenylamines, such as monooctyl diphenylamine and monononyl diphenylamine; 4,4'-dibutyldiphenylamine, 4,4'-dipentyldiphenylamine, 4,4'-dihexyldiphenylamine, 4,4'-diheptyldiphenylamine, 4,4'-dioctyldiphenylamine Dialkyl diphenylamines such as 4,4'-dinononyldiphenylamine; Polyalkyldiphenylamines such as tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine and tetranonyldiphenylamine; α-naphthylamine, phenyl-α-naphthylamine, butylphenyl-α-naphthylamine, pentylphenyl-α-naphthylamine, hexylphenyl-α-naphthylamine, heptylphenyl-α-naphthylamine, And naphthylamines such as octylphenyl-α-naphthylamine and nonylphenyl-α-naphthylamine.

As a phenolic antioxidant, 2, 6- di- t-butyl- l-cresol (dibutyl hydroxy toluene; BHT), butylated hydroxy anisole, 2, 6- di- t-butyl-4- ethylphenol type Monophenol antioxidants such as stearin-β- (3,5-di-tet-butyl-4-hydroxyphenyl) propionate; 2,2'-methylenebis (4-methyl-6- tet-butylphenol), 2,2'-methylenebis (4-ethyl-6- tet-butylphenol), 4,4'-thiobis (3- Methyl-6-tet-butylphenol), 4,4'-butylidenebis (3-methyl-6-tet-butylphenol), 3,9-bis [1,1-dimethyl-2- [β- ( Bisphenol antioxidants such as 3-tet-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxaspiro [5,5] undecane; 1,1,3-tris (2-methyl-4-hydroxy-5-ｔ-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-ｔ- Butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ', 5'-di-pent-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3' -Bis- (4'-hydroxy-3'-tet-butylphenyl) butyric acid] glycol ester, 1,3,5-tris (3 ', 5'-di-ｔ-butyl-4'-hydroxybenzyl And polymer type phenolic antioxidants such as) -S-triazine-2,4,6- (1H, 3H, 5H) trione and tocophenolic compounds.

From the viewpoint of suppressing photocuring by radicals generated from photoradical initiators by light such as fluorescent lamps, among antioxidants, it is preferable to act as radical chain inhibitors such as amine antioxidants and phenolic antioxidants. Especially preferred are phenolic antioxidants having a phenol structure.

An antioxidant having a hindered phenol structure is one in which a hindered group such as a tert-butyl group is bonded to at least one of the adjacent carbon atoms to an aromatic cyclic carbon atom to which the OH group of the phenol is bonded. Examples of the antioxidant having a hindered phenol structure include dibutylhydroxytoluene (BHT) and pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (BASF Corporation) Manufactured, 'Irganox' 1010 '), octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (manufactured by BASF,' Irganox '1076') , 3,3 ', 3 ", 5,5', 5" -hexa-tert-butyl-a, a ', a "-(mesitylene-2,4,6-triyl) tri-y-cresol ( Manufactured by BASF, 'Irganox® 1330'), 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4, 6 (1H, 3H, 5H) -trione (manufactured by BASF, 'Irganox 3114'), isocyanuric acid tris [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl Oxyethyl] (manufactured by BASF, 'Irganox 3125'), pentaerythritol tetrakis [3- (3,5-di-tetert-butyl-4-hydroxyphenyl) propionate] (manufactured by Adeka Corporation, 'Adecastop AO-60'), 3,9-bis {2- [3- (3-ｔert-butyl-4-hydroxy -5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane (made by Adeka Co., Ltd. ), Acrylic acid 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl (manufactured by Sumitomo Chemical Co., Ltd., 'Sumilizer-KS') , 2-tert-butyl-4-methyl-6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl (manufactured by Sumitomo Chemical Co., Ltd., 'Smallizer GM'), 2,2'-dimethyl -2,2 '-(2,4,8,10-tetraoxaspiro [5.5] undecane-3,9-diyl) dipropane-1,1'-diyl = bis [3- (3-tert -Butyl-4-hydroxy-5-methylphenyl) propanoate] ("Sumiiser GA-80" manufactured by Sumitomo Chemical Co., Ltd.), 1,3,5-tris (3-hydroxy-4-tert-butyl-2 , 6-dimethylbenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione ("Dioxox 1790" manufactured by Scitech Corporation).

As for content of the antioxidant in the adhesive layer 2, 0.01-2 weight part is preferable with respect to 100 weight part of base polymers, 0.03-1 weight part is more preferable, 0.04-0.7 weight part is more preferable, 0.05-0.5 weight part Particularly preferred. 0.2-5 times of content of an optical radical initiator is preferable, as for content of antioxidant, 0.3-3 times are more preferable, and 0.5-2 times are more preferable.

(Combination Effect of Photoradical Initiator and Antioxidant)

In a composition containing an antioxidant in addition to the photoradical initiator, even when a small amount of photoradical is generated from the photoradical initiator by light from a fluorescent lamp or the like, the antioxidant traps radicals and generates stable radicals. Therefore, radical polymerization reaction by the light from a fluorescent lamp etc. is suppressed. From a viewpoint of suppressing the polymerization reaction in the storage state of a reinforcement film, it is preferable that content of antioxidant is large. On the other hand, if the content of the antioxidant is excessively large, the antioxidant traps most of the photogenerated radicals even when irradiated with ultraviolet rays for photocuring, thereby preventing radical migration from the photoradical initiator to the photocuring agent, resulting in insufficient photocuring. It may become. Therefore, in order to suppress photopolymerization in a storage environment, to prevent an increase in adhesive force, and to advance a photocuring reaction appropriately at the time of light irradiation, and to raise adhesive force, it is preferable that content of antioxidant is the said range.

By using an optical radical initiator and antioxidant together, since an antioxidant traps the radical produced | generated by the light from fluorescent lights etc., the raise of the adhesive force by the photocuring reaction in a storage environment can be suppressed. Therefore, photocuring of the adhesive layer in a storage environment can be suppressed by an action of antioxidant irrespective of the kind of optical radical initiator.

On the other hand, when the reinforcement film provided with the adhesive layer containing an optical radical initiator and antioxidant is exposed to fluorescent lamp for a long time, the effective concentration of an optical radical initiator (concentration of the optical radical initiator which can produce | generate an optical radical) by deactivation of an optical radical initiator Decreases. Therefore, even when irradiated with ultraviolet rays for photocuring, the amount of optical radicals generated is small, and the photocuring reaction may not proceed sufficiently.

The reinforcing film is hard to generate photocuring of the pressure-sensitive adhesive by light such as fluorescent lamp even after long-term storage, and also generates sufficient amount of radicals when irradiated with light, so that the adhesive strength with the adherend is increased by radical polymerization reaction of the photocuring agent. It is desirable to rise. In order to fully advance the photocuring reaction even after long-term storage, it is preferable to use an optical radical initiator with a small amount of radical generation in a storage environment. Specifically, as described above, it is preferable to use an optical radical initiator having an absorption maximum wavelength at 360 nm or less and having a small amount of optical radicals generated by mercury bright lines (especially wavelength 365 nm) of fluorescent lamps.

The amount of radicals generated from the photoradical initiator by the light of a fluorescent lamp can be evaluated by, for example, irradiating light having a wavelength of 365 nm at cryogenic temperatures and quantifying the amount of radicals by electron spin resonance (ESR) as shown in Examples described later. have. Since radicals derived from photo-radical initiators have extremely short lifespan at room temperature, the cryogenic temperature is suitable for evaluation of the amount of radicals produced.

(Other additives)

In addition to each component of the said example, in an adhesive layer, additives, such as a silane coupling agent, a tackifier, a plasticizer, a softener, a deterioration inhibitor, a filler, a coloring agent, a ultraviolet absorber, surfactant, an antistatic agent, do not impair the characteristic of this invention. You may contain in.

[Production of reinforcement film]

A reinforcement film is obtained by laminating | stacking the photocurable 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-mentioned pressure-sensitive adhesive composition is described on a 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 and the like. Is applied, and the pressure-sensitive adhesive layer is formed by drying the solvent as necessary. As a drying method, a suitable and appropriate method can be adopted. The heat drying temperature is preferably 40 ° C to 200 ° C, more preferably 50 ° C to 180 ° C, still 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 adhesive layer 2 is about 1-300 micrometers, for example. There exists a tendency for adhesiveness with a to-be-adhered body to improve that the thickness of the adhesive layer 2 is large. On the other hand, when the thickness of the adhesive layer 2 is excessively large, the fluidity | liquidity before photocuring may be high and handling may become difficult. Therefore, 5-100 micrometers is preferable, as for the thickness of the adhesive layer 2, 8-50 micrometers is more preferable, 10-40 micrometers is still more preferable, 13-30 micrometers is especially preferable.

When an adhesive composition contains a crosslinking agent, it is preferable to advance bridge | crosslinking by heating or aging simultaneously with drying of a solvent or after drying of a solvent. Heating temperature and a heat time are suitably set according to the kind of crosslinking agent to be used, and bridge | crosslinking is normally performed by heating for about 1 minute-about 7 days in 20 degreeC-160 degreeC. Heating for drying and removing the solvent may also serve as heating for crosslinking.

The gel fraction is increased by introducing a crosslinked structure into the base polymer. The higher the gel fraction, the harder the pressure-sensitive adhesive and the tendency of the adhesive residue on the adherend to be peeled off during peeling of the reinforcing film from the adherend by rework or the like. The gel fraction of the pressure-sensitive adhesive layer 2 before photocuring is preferably 30% or more, more preferably 50% or more, still more preferably 60% or more, and particularly preferably 65% or more. The gel fraction before photocuring of the adhesive layer 2 may be 70% or more or 75% or more.

Since an adhesive contains an unreacted photocuring agent, the gel fraction of the adhesive layer 2 before photocuring is generally 90% or less. When the gel fraction of the adhesive layer 2 before photocuring is excessively large, the anchoring force with respect to a to-be-adhered body may fall, and initial stage adhesive force may become inadequate. Therefore, 85% or less is preferable and, as for the gel fraction of the adhesive layer 2 before photocuring, 80% or less is more preferable.

The gel fraction can be obtained as an insoluble content in a solvent such as ethyl acetate. Specifically, the weight fraction (unit: weight%) of the sample before immersion of the insoluble component after immersing the pressure-sensitive adhesive layer in ethyl acetate at 23 ° C. for 7 days. It can be obtained as In general, the gel fraction of the polymer is equal to the degree of crosslinking, and the more crosslinked moieties in the polymer, the larger the gel fraction. Also, the greater the amount of photocuring agent, the smaller the gel fraction.

Even after the crosslinking structure is introduced into the polymer by the crosslinking agent, the photocuring agent remains in an unreacted state. Therefore, the photocurable adhesive layer 2 containing a base polymer and a photocuring agent is formed. When forming the adhesive layer 2 on the film base material 1, it is preferable to provide the separator 5 on the adhesive layer 2 for the purpose of protection of the adhesive layer 2, etc. After the separator 5 is placed on the pressure-sensitive adhesive layer 2, crosslinking may be performed.

When forming the adhesive layer 2 on another base material, a reinforcement film is obtained by transferring the adhesive layer 2 on the film base material 1 after drying a solvent. The base material used for formation of an adhesive layer may be used as the separator 5 as it is.

As the separator 5, plastic films, such as polyethylene, a polypropylene, a polyethylene terephthalate, and a polyester film, are used preferably. The thickness of the separator is usually 3 to 200 µm, preferably about 10 to 100 µm. It is preferable that the release surface of the separator 5 to the contact surface with the adhesive layer 2 is performed by mold release agents, such as a silicone type, a fluorine type, a long chain alkyl type, or a fatty acid amide type, or a silica powder. When the surface of the separator 5 is mold-release-processed, peeling occurs at the interface of the adhesive layer 2 and the separator 5 when peeling the film base material 1 and the separator 5, and the film base material 1 The state which the adhesive layer 2 adhered on is hold | maintained.

 [Use of reinforcement film]

The reinforcement film of this invention is used by bonding to a device or a device component. The reinforcement film 10 has the adhesive layer 2 fixed to the film base material 1, and the adhesive force to the to-be-adhered body is small before the photocuring after bonding with the to-be-adhered body. Therefore, before photocuring, peeling of a reinforcement film from an adherend is easy and it is excellent in rework property. Further, before photocuring, processing such as cutting the reinforcing film and removing the reinforcing film of a part of the surface of the adherend can also be easily performed.

The to-be-adhered body to which a reinforcement film is bonded is not specifically limited, Various electronic devices, an optical device, its component parts, etc. are mentioned. The reinforcement film may be bonded to the entire surface of the adherend, or may be selectively bonded only to a portion requiring reinforcement. Moreover, after bonding a reinforcement film on the whole surface of a to-be-adhered body, you may cut | disconnect and remove the reinforcement film of the part which does not need reinforcement. If it is before photocuring, since a reinforcement film is a state stuck to the surface of a to-be-adhered body, peeling removal of a reinforcement film from the surface of a to-be-adhered body can be performed easily.

<Characteristics of the pressure-sensitive adhesive layer before photocuring>

(Adhesion)

From the viewpoint of facilitating peeling from the adherend and preventing adhesive residue on the adherend after peeling the reinforcing film, the adhesive force between the pressure-sensitive adhesive layer 2 and the adherend before photocuring is preferably 5 N / 25 mm or less, 2N / 25mm or less is more preferable, and 1.3N / 25mm or less is more preferable. From the viewpoint of preventing peeling of the reinforcing sheet during storage or handling, the adhesive force between the pressure-sensitive adhesive layer 2 and the adherend before photocuring is preferably 0.005 N / 25 mm or more, more preferably 0.01 N / 25 mm or more. , 0.1 N / 25 mm or more is more preferable, and 0.3 N / 25 mm or more is particularly preferable.

It is preferable that the adhesive force with respect to a polyimide film exists in the said range in the state before a reinforcement film photocures an adhesive layer. In a flexible display panel, a flexible printed wiring board (FPC), a device in which a display panel and a wiring board are integrated, a flexible substrate material is used, and a polyimide film is generally used in view of heat resistance and dimensional stability. The reinforcement film whose adhesive layer has said adhesive force with respect to the polyimide film as a board | substrate is easy to peel before photocuring of an adhesive, and is excellent in adhesive reliability after photocuring.

(Save modulus)

Pressure-sensitive adhesive layer (2) preferably has a shear storage modulus (G _'i) in 25 ℃ before photocuring of ^{1 × 10 4 ~1.2 × 10 5} ㎩. Shear storage modulus (hereinafter, simply referred to as "storage modulus") is based on the method described in JIS K7244-1 "Test method of plastic-dynamic mechanical properties", and is -50 to 150 ° C under conditions of frequency 1 Hz. It is calculated | required by reading the value in the predetermined temperature at the time of measuring by the temperature increase rate 5 degree-C / min in the range.

In a material exhibiting viscoelasticity, such as an adhesive, the storage modulus (G ') is used as an index indicating the degree of hardness. The storage 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 tendency for the anchoring force to the adherend to increase. If the storage elastic modulus of the adhesive layer 2 before photocuring is 1 * 10 <^4> Pa or more, since an adhesive has sufficient hardness and cohesion force, the adhesive residue to a to-be-adhered body hardly arises when peeling a reinforcement film from an to-be-adhered body. Moreover, when the storage elastic modulus of the adhesive layer 2 is large, it can suppress that an adhesive pushes out from the end surface of a reinforcement film. If the storage elastic modulus of the adhesive layer 2 before photocuring is 1.2 * 10 <^5> Pa or less, peeling at the interface of the adhesive layer 2 and a to-be-adhered body will be easy, and even if it reworks, the cohesive failure of an adhesive layer and an adherend Adhesive residue on the surface is unlikely to occur.

From the viewpoint of increasing the reworkability of the reinforcing sheet and suppressing the adhesive residue on the adherend during rework, the storage modulus (G ′ _i ) at 25 ° C. before photocuring of the pressure-sensitive adhesive layer 2 is 3 × 10 ⁴ to 1 * 10 <^5> Pa is more preferable, and 4 * 10 <^4> -9.5 * 10 <^4> Pa is further more preferable.

<Photocuring of the adhesive layer>

After bonding a reinforcement film to a to-be-adhered body, an adhesive layer is photocured by irradiating actinic light to the adhesive layer 2. Examples of the active light include ultraviolet rays, visible light, infrared rays, X-rays, α rays, β rays, and γ rays. Since the hardening of the adhesive layer in a storage state can be suppressed, and hardening is easy, an ultraviolet ray is preferable as an actinic light. What is necessary is just to set irradiation intensity and irradiation time of an actinic light suitably according to the composition, thickness, etc. of an adhesive layer. Irradiation of the actinic light to the adhesive layer 2 may be performed from either the film base material 1 side, and the to-be-adhered body side, and you may irradiate an actinic light from both surfaces.

<Characteristics of the pressure-sensitive adhesive layer after photocuring>

(Adhesion)

From the viewpoint of the adhesion reliability in actual use of the device, the adhesive force between the pressure-sensitive adhesive layer 2 and the adherend after photocuring is preferably 6 N / 25 mm or more, more preferably 10 N / 25 mm or more, further 12 N / 25 mm or more It is preferable and 14N / 25mm or more is especially preferable. It is preferable that the adhesive layer after photocuring of the reinforcement film has the adhesive force of the said range with respect to a polyimide film. As for the adhesive force of the adhesive layer 2 and a to-be-adhered body after photocuring, four times or more of the adhesive force of the adhesive layer 2 and a to-be-adhered body before photocuring is preferable, eight times or more are more preferable, and ten times or more are furthermore desirable.

Pressure-sensitive adhesive layer (2) It is preferable that the storage elastic modulus (G _'f) at 25 ℃ after the photo-curing is not less than 1.5 × 10 ⁵ ㎩. If the storage elastic modulus of the adhesive layer 2 after photocuring is 1.5 * 10 <^5> Pa or more, the adhesive force with a to-be-adhered body will improve according to the increase of cohesion force, and high adhesive reliability will be obtained. On the other hand, when the storage elastic modulus is excessively large, the pressure-sensitive adhesive is difficult to wet and diffuse, and the contact area with the adherend becomes small. Moreover, since the stress dispersibility of an adhesive falls, peeling force tends to propagate to an adhesive interface, and there exists a tendency for the adhesive force with a to-be-adhered body to fall. Thus, the storage modulus (G _'f) at 25 ℃ after the photo-curing of the pressure-sensitive adhesive layer (2) is preferably not more than 2 × 10 ⁶ ㎩. In view to increase the adhesion reliability of the reinforcing sheet after the photocurable pressure-sensitive adhesive layer, G _'f is ^{1.8 × 10 5 ~1.2 × 10 6} ㎩ is more preferable, and more preferable ^{2 × 10 5 ~1 × 10 6} ㎩ .

Ratio _{(G 'f / G' i} ) of the storage elastic modulus at 25 ℃ before and after the photo-curing pressure-sensitive adhesive layer (2) is, for more than two are preferable. If G 'is G _{f' i} of at least twice, an increase in G 'by photocuring large, it is possible to achieve both adhesion reliability after photocuring before rework and photocuring. G _'f / G' _i is 4 or more is more preferable, and 8 or more is more preferred, more than 10 are particularly preferred. The upper limit of G ' _f / G' _i is not particularly limited, but when G ' _f / G' _i is excessively large, initial adhesion failure due to small G 'before photocuring or G' after photocuring is excessive It is easy to be connected to the fall of the adhesive reliability by large. Thus, G _'f / G' _i is not more than 100 is preferable, and particularly preferably less are more preferred, and 30 or less is more preferable, and not more than 25 40.

The to-be-adhered body after laying out a reinforcement film may perform heat processing, such as autoclave processing for the purpose of affinity improvement of the lamination | stacking interface of several laminated members, and thermocompression bonding for a circuit member joining. When such heat processing is performed, it is preferable that the adhesive between a reinforcement film and a to-be-adhered body does not flow from a cross section.

From a viewpoint of suppressing an adhesive sticking out at the time of high temperature heating, 5 x 10 <^4> Pa or more is preferable, and, as for the storage elastic modulus in 100 degreeC of the adhesive layer 2 after photocuring, 8 * 10 <^4> Pa or more is more preferable. , 1 × 10 ⁵ Pa or more is more preferable. In addition to preventing the pressure-sensitive adhesive from being pushed out during heating, the storage elastic modulus at 100 ° C. of the pressure-sensitive adhesive layer 2 after photocuring is 60% or more of the storage elastic modulus at 50 ° C. It is preferable, 65% or more is more preferable, 70% or more is more preferable, 75% or more is especially preferable.

[Use form of reinforcement film]

The reinforcement film of this invention is bonded together and used for the structural member (worked product) of various devices, and the device after completion. By bonding a reinforcement film, since moderate rigidity is provided, handling property improvement and damage prevention effect are anticipated. In the manufacturing process of a device, when a reinforcement film is bonded to a work in progress, you may bond a reinforcement film to the large work before cutting to product size. You may bond a reinforcement film with a roll to roll on the mother roll of the device manufactured by a roll to roll process.

The thickness of the members constituting the device tends to be small due to the high integration, small size, and thinness of the device. Due to the thinning of the constituent members, curvature and curl due to stress or the like at the laminated interface tend to occur. In addition, the thinning tends to cause warping according to its own weight. By bonding a reinforcement film, rigidity can be provided to a to-be-adhered body, curvature, curl, curvature, etc. by stress, its own weight, etc. are suppressed, and handling property improves. Therefore, by bonding the reinforcing film to the work in the manufacturing process of the device, it is possible to prevent defects or problems during conveyance and processing by the automated apparatus.

In automatic conveyance, contact with the workpiece | work in progress of a conveyance object, a conveyance arm, a pin, etc. is inevitable. In addition, cutting of a work in some cases may be performed in order to adjust a shape and to remove an unnecessary part. In high integration, small size, light weight, and thin devices, breakage due to local concentration of stress is likely to occur in contact with the conveying device or the like. In the manufacturing process of the device which laminated | stacked the some member, not only the member is laminated | stacked sequentially but a part of a member, process material, etc. may be peeled off from a work. In the case where the member is thin, stress may be locally concentrated in the peeling part and its vicinity, resulting in breakage or dimensional change. Since the reinforcing film has stress dispersibility by the pressure-sensitive adhesive layer, the reinforcing film is bonded to the conveying object and the object to be processed, thereby providing appropriate rigidity, while alleviating and dispersing stress, and problems such as cracking, cracking, peeling, and dimensional change. Can be suppressed.

Thus, by bonding the reinforcing film of the present invention, the rigidity is given to the work in the adherend, and the stress is alleviated and dispersed, thereby suppressing various problems that may occur in the manufacturing process, improving production efficiency, and improving yield. can do. In addition, since the reinforcement film is easy to peel from the adherend before photocuring the pressure-sensitive adhesive layer, rework is easy even when lamination or bonding failure occurs.

In the reinforcement film of this invention, the adhesive layer 2 is photocurable, and the timing of hardening can be set arbitrarily. Processing such as reworking or processing of reinforcing film can be performed at any timing from when the reinforcing film is placed on the adherend to the time of curing the pressure-sensitive adhesive, thereby flexibly supporting the lead time of the manufacturing process of the device. It is possible. As mentioned above, since an adhesive layer contains antioxidant in addition to a photocuring agent and a photoradical initiator, photocuring by light, such as a fluorescent lamp, is hard to advance. Therefore, even when the reinforcing film is stored on the adherend for a long time, peeling of the reinforcing film from the adherend is easy before photocuring.

In the use of the device after completion, the reinforcing film is bonded even when an unexpected external force is loaded due to the drop of the device, the loading of a heavy object onto the device, the collision of flying objects on the device, or the like. Damage to the device can be prevented. Moreover, since the reinforcement film after photocuring an adhesive is firmly adhere | attached to a device, peeling of a reinforcement film is difficult also in long-term use, and it is excellent in reliability.

(Example)

Although an Example is given to the following and is further demonstrated, this invention is not limited to these Examples.

[Production of reinforcement film]

Polymerization of Base Polymer

63 parts by weight of 2-ethylhexyl acrylate (2EHA), 15 parts by weight of N-vinylpyrrolidone (NVP), and methyl methacrylate in a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas inlet tube. (MMA) 9 parts by weight, hydroxyethyl acrylate (HEA) 13 parts by weight, 0.2 parts by weight of azobisisobutylonitrile as a thermal polymerization initiator, and 233 parts by weight of ethyl acetate as a solvent, flowing nitrogen gas and stirred Nitrogen substitution was performed for about 1 hour. Then, it heated at 60 degreeC and made it react for 7 hours, and obtained the solution of the acrylic polymer A whose weight average molecular weight (Mw) is 1.2 million.

 <Preparation of adhesive composition>

Mitsui Chemical Co., Ltd., `` Takenate D110N '' (75% ethyl acetate solution of trimethylolpropane adduct of xylylene diisocyanate) as an acrylic polymer solution, Shinnakamura Chemical Co., Ltd., 'A-200' as a polyfunctional acrylic monomer ( Polyethylene glycol # 200 (n = 4) diacrylate; molecular weight tube 308, functional group equivalent 154 g / eq), optical radical initiator and antioxidant were added and mixed uniformly to prepare an adhesive composition. The compounding quantity (solid content) of a crosslinking agent was 2.5 weight part with respect to 100 weight part of base polymers, and the compounding quantity of the polyfunctional acrylic monomer was 30 weight part with respect to 100 weight part of base polymers. As antioxidant, pentaerythritol tetrakis [3- (3,5-di-tert- butyl- 4-hydroxyphenyl) propionate] (The amount which shows "Iruganox 1010" by BASF Corporation in Table 1) As an optical radical initiator, the thing shown below was mix | blended in the quantity shown in Table 1.

(Optical radical initiator)

IRG184: 1-hydroxycyclohexylphenyl ketone (BASF Corporation make, "Iruganox 184", absorption maximum wavelength: 246nm, 280nm, 333nm)

IRG651: 2,2-dimethoxy-1,2-diphenylethan-1-one (made by BASF, "Iruganox 651", absorption maximum wavelength: 250nm, 340nm)

IRG819: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (made by BASF, "Irugacure 819", absorption maximum wavelength: 295nm, 370nm)

<Application and Crosslinking of Adhesive Solution>

On the 75-micrometer-thick polyethylene terephthalate film (Toray Co., Ltd., "Lumira S10") which was not surface-treated, the said adhesive composition was apply | coated using a fountain roll so that the thickness after drying might be 25 micrometers. After drying at 130 degreeC for 1 minute and removing a solvent, the mold release process surface of the separator (25 micrometers thickness polyethylene terephthalate film in which the surface was silicone-release-processed) was bonded to the coating surface of an adhesive. Thereafter, an aging treatment was performed for 4 days in an atmosphere at 25 ° C., crosslinking was carried out, and the photocurable pressure sensitive adhesive sheet was fixedly laminated on the film substrate, thereby obtaining a reinforcing film having a separator attached thereto.

[Measurement of Adhesive Force]

A polyimide film (Kapton 50EN manufactured by Toray DuPont) having a thickness of 12.5 μm was attached to the glass plate via a double-sided adhesive tape (No. 531, manufactured by Nitto Denko), and the polyimide film substrate for measurement was Got it. The separator was peeled off from the surface of the reinforcing film cut out to width 25mm x length 100mm, it bonded to the polyimide film board | substrate for measurement using a hand roller, and it was set as the test sample before photocuring. From the reinforcement film side (PET film side) of the test sample before photocuring, the ultraviolet-ray of the integrated light quantity 400mJ / cm <^2> was irradiated using the LED light source of wavelength 365nm, and what photocured the adhesive layer was made into the test sample after photocuring. Using these test samples and holding the end of the polyethylene terephthalate film of the reinforcing film as a chuck, 180 ° peeling of the reinforcing film was performed at a tensile speed of 300 mm / min to measure the peel strength.

<Evaluation of adhesive strength of reinforcing film after storage for a period of time>

The reinforcing sheet was left under room temperature at room temperature, and after one week and after four weeks, the reinforcing sheet was bonded to the polyimide film substrate for measurement, and 180 ° peel strength was measured as above on the test sample before and after photocuring.

TABLE 1

In any of the samples, immediately after fabrication, peeling from the adherend was easy in the range of 0.2 to 0.4 N / 25 mm of adhesive force before photocuring, and after photocuring, the adhesive force rose to 15 N / 25 mm or more to firmly adhere to the adherend. Was doing.

In the sample 10 using the adhesive containing no antioxidant, the adhesive force before photocuring increased significantly in the sample after storage for 4 weeks, and peeling from the adherend was difficult. On the other hand, in the sample 11 to which 0.1 weight part of antioxidant was added, although the adhesive force before photocuring rose slightly in the sample after storage for 4 weeks, peeling from the to-be-adhered body was fully possible. In addition, in the sample 11, the adhesive force after photocuring of the sample after storage for 4 weeks was equivalent to the sample immediately after manufacture.

In the sample 20 and the sample 30 using the adhesive which does not contain antioxidant, similarly to the sample 10, the adhesive force before photocuring showed the big increase in the sample after storage for 4 weeks. In the sample 20 and the sample 30, the adhesive force before photocuring also rose to 10 N / 25 mm or more also in the sample after 1 week storage. In the sample 21 and the sample 31 to which 0.1 weight part of antioxidant was added, even the sample after 1 week storage showed low adhesive force before photocuring, and high adhesive force after photocuring.

In contrast to the above results, reinforcement exhibiting excellent reworkability from the adherend before photocuring even when stored under a fluorescent lamp for a long time by using an optical radical initiator and an antioxidant together, and exhibiting high adhesion to the adherend by photocuring. It can be seen that a film can be obtained.

In the sample 12 to which 0.5 weight part of antioxidant was added, the increase rate of the adhesive force by photocuring fell after 1 week storage, and the adhesive force did not raise most, even if it irradiated with ultraviolet rays after 4 weeks storage. In the sample 13 to which 1 weight part of antioxidant was added, even after storage for 1 week, the raise of the adhesive force by ultraviolet irradiation was inadequate. Also in the contrast between the samples 21 to 23 and the contrast between the samples 31 to 33, there was a tendency that the adhesive force did not increase even when the ultraviolet rays were irradiated with the increase in the amount of the antioxidant added.

From these results, when the addition amount of antioxidant is large, it can be said that there exists a tendency for photocuring to become difficult to progress as the storage period from sample preparation becomes long. This is considered to be because the amount of radicals generated is small even when the radical radical is deactivated and irradiated with ultraviolet rays as the storage period under the fluorescent lamp becomes longer from the sample preparation.

When the storage period under fluorescent lamps becomes long and the effective concentration of the photoradical initiator decreases, the amount of radicals generated during ultraviolet irradiation decreases. Antioxidants have the effect of trapping radicals generated from photoradical initiators by light such as fluorescent lamps in storage environments, thereby inhibiting undesired photoradical polymerization, but trapping radicals even when irradiated with ultraviolet rays for photocuring. Has action. Therefore, when the storage period under a fluorescent lamp is long and the effective concentration of the photoradical initiator is low, the ratio of radicals trapped by the antioxidant in the photoradical generated from the photoradical initiator is high, and the ratio of radicals contributing to the photoradical polymerization is increased. Lowers. Since the larger the content of the antioxidant, the greater the polymerization inhibitory effect (polymerization inhibition), the photoradical reaction of the photocuring agent is less likely to proceed even when irradiated with ultraviolet rays, and it is considered that the adhesive force does not sufficiently increase.

From the above results, by appropriately adjusting the amount of the antioxidant used in combination with the photoradical initiator, the photocuring agent has excellent reworkability from the adherend even when the storage period under a fluorescent lamp is long, and photocuring is appropriate by ultraviolet irradiation. It can be seen that a reinforcing film capable of achieving high adhesive strength is obtained.

[Measurement and Discussion of Radical Concentration by Electron Spin Resonance]

Radical production was evaluated by ESR by irradiating light at cryogenic temperature in order to verify the radical production amount and the effect of the antioxidant of the photoradical initiator used in the above examples.

Ethyl acetate at a concentration of 0.2 mol / L for each of the photoradical initiator (IRG184, IRG651 or IRG819) alone, the antioxidant (Iruganox 1010) alone, and the combination of the photoradical initiator (Irg651 or Irg819) with antioxidant The solution was prepared (in the combined system, each concentration was 0.2 mol / L). 0.1 mL of the sample solution was loaded into an ESR sample tube (a quartz tube of about 3.5 mmφ), set in a cavity of the ESR, and subjected to light irradiation ESR measurement at a temperature of 40K. The ultra-high pressure mercury lamp (made by Ushio Electric Co., Ltd.) was cut into the lamp of light irradiation, the short wavelength light of wavelength 290nm or less was cut out with the glass filter, and the hot wire was cut out with the water filter. The illuminance (wavelength 365nm) measured from the front of the cavity was 18 mW / cm ² . Equipment and main measurement conditions are shown below.

Apparatus: ESP350E (manufactured by Brooker)

Accessory Device: HP5351B Microwave Frequency Counter (manufactured by Hewlett-Packard)

ER035M gauss meter (manufactured by Brooker)

ESR910 cryostat (manufactured by Brooker)

Cavity: TM110, Cylindrical

Measuring temperature: 40 K

Center magnetic field: 3385 G

Magnetic field sweep width: 400 G

Modulation: 100 kHz, 10 G

Microwave: 9.49 GHz, 0.16 mW

Draft time: 83.89 seconds × 2 times

Time constant: 327.68 milliseconds

Number of data points: 1024

5 minutes after the start of light irradiation, 10 minutes later, 20 minutes later, 30 minutes later, 40 minutes later, 50 minutes later, and 60 seconds later, the amount of radicals was quantified by the calibration curve method. The graph which plotted light irradiation time and radical concentration about each sample is shown in FIG.

Looking at the three kinds of photo-radical initiator, Irugacure 819 (IRG819) showed the highest radical generation amount. This is considered to be attributable to the fact that IRG819 exhibits an absorption maximum at a wavelength of 370 nm and has high sensitivity to irradiated light (wavelength of 365 nm). In Irugacure 184 (IRG184) and Irugacure 651 (IRG651), Irugacure 651 showed a large amount of radicals.

The amount of such radicals is correlated with the change of the adhesive force before photocuring at the time of storage of the sample 10, the sample 20, and the sample 30 under the fluorescent lamp. That is, since Irugacure 184 has a small amount of radicals generated by light from the fluorescent lamp, the sample 10 does not show an increase in adhesive strength before photocuring after storage for one week, whereas the Irugacure 651 sample (20) is used. ) And the sample 30 using Irugacure 819, since the amount of optical radicals generated by light from the fluorescent lamp is relatively large, it is considered that the adhesive force before photocuring is increased in the sample after storage for one week.

Antioxidant (irganox 1010) showed a radical concentration higher than three types of photoradical initiators. This is considered to be related to the high amount of radicals that accumulate in the system with increasing light irradiation time because the stability of radicals generated from the antioxidant is high and the amount of radical loss is smaller than that of the photoradical initiator.

In the combination system of an optical radical initiator (IRG651 or IRG819) and antioxidant, the radical concentration lower than the case of antioxidant alone was shown. Since the radical concentration of a combined system is smaller than the sum of the case of an optical radical initiator alone and the antioxidant alone, it is thought that the radical produced | generated from the radical radical was trapped by antioxidant.

Claims (9)

A film base material and the adhesive layer fixedly laminated on one main surface of the said film base material are provided,
The pressure-sensitive adhesive layer is made of a photocurable composition comprising a base polymer, a photocuring agent, an optical radical initiator, and an antioxidant, wherein the photocuring agent is 10 to 50 parts by weight and the optical radical initiator is 0.01 to 100 parts by weight of the base polymer. The reinforcement film containing 0.01 weight part-1 weight part and the said antioxidant. The method of claim 1,
The reinforcement film whose content of the said antioxidant is 0.2-5 times of content of the said photo radical initiator. The method according to claim 1 or 2,
The said radical photoinitiator has an absorption maximum in the range of wavelength 310 nm-355 nm, and does not show absorption maximum in longer wavelength than 360 nm. The method according to claim 1 or 2,
The reinforcement film in which the said base polymer contains 1 or more types chosen from the group which consists of a hydroxyl group containing monomer and a carboxy group containing monomer as a monomer unit, and the crosslinking structure is introduce | transduced by the crosslinking agent couple | bonded with the hydroxy group or the carboxy group. The method according to claim 1 or 2,
A reinforcing film containing an acrylic polymer as said base polymer. The method of claim 5,
The said acryl-type polymer contains 5-50 weight% of monomer components whose glass transition temperature of a homopolymer is 40 degreeC or more. The method according to claim 1 or 2,
The reinforcing film, wherein the photocuring agent is polyfunctional (meth) acrylate. The method according to claim 1 or 2,
The reinforcement film whose functional group equivalent of the said photocuring agent is 100-500 g / eq. The method according to claim 1 or 2,
The reinforcement film whose adhesive force of the said adhesive layer and polyimide film is 0.005-5 N / 25mm, and adhesive force with the polyimide film after photocuring the said adhesive bond layer is 6N / 25mm or more.

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