KR20210126633A - Device including reinforcing film, manufacturing method thereof, and reinforcing method - Google Patents

Abstract

The reinforcing film 5 is provided with the photocurable adhesive layer 2 fixedly laminated|stacked on one main surface of the film base material 11. As shown in FIG. An antistatic layer 12 containing a conductive polymer and a binder is provided on the back surface of the film substrate. After the pressure-sensitive adhesive layer of the reinforcing film is temporarily attached to the surface of the adherend 9, the pressure-sensitive adhesive layer is photocured by irradiating actinic light to the pressure-sensitive adhesive layer from the antistatic layer formation surface side of the film substrate. When photocuring an adhesive layer, deterioration of an antistatic layer can be suppressed by not irradiating the ultraviolet-ray with a wavelength of 200-280 nm to an antistatic layer.

Description

Device including reinforcing film, manufacturing method thereof, and reinforcing method

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

An adhesive film may be adhere|attached on the surface of optical devices, such as a display, or an electronic device for the purpose of surface protection, impact resistance provision, etc. Usually, the adhesive layer is fixedly laminated|stacked on the main surface of a film base material, and such an adhesive film is bonded to the device surface through this adhesive layer.

In the state before use, such as assembly, processing, transportation, etc. of a device, by temporarily adhering an adhesive film to the surface of a device or a device component, the generation|occurrence|production or damage of a to-be-adhered body can be suppressed. As described above, it is required that the adhesive film temporarily attached for the purpose of protecting the surface can be easily peeled off from the adherend and that no adhesive residue is generated on the adherend.

Patent Document 1 discloses a pressure-sensitive adhesive film that is used in a state of being adhered to the device surface even when the device is used in addition to assembly, processing, transportation, and the like of the device. In addition to surface protection, such an adhesive film has the function of reinforcing a device by dispersion|distribution of the impact to a device, rigidity provision to a flexible device, etc.

When bonding an adhesive film to a to-be-adhered body, bonding defects, such as mixing of a bubble and a shift|offset|difference of an attachment position, may arise. When bonding defect arises, an operation|work (rework) which peels an adhesive film from a to-be-adhered body, and bonds another 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 the reinforcing film premised on permanent adhesion is not generally assumed to be peeled from a device and is firmly adhere|attached to the surface of a device, rework is difficult.

Patent Document 2 discloses an adhesive film in which a photocurable pressure-sensitive adhesive layer is provided on the surface of the hard coat film. The photocurable pressure-sensitive adhesive has a small adhesive force with the adherend before photocuring, so it is easy to peel from the adherend.

Japanese Patent Laid-Open No. 2017-132977 Japanese Patent Laid-Open No. 2015-217530

In a reinforcing film in which a photocurable pressure-sensitive adhesive layer is adhered and laminated on a film substrate, by providing an antistatic layer on the film substrate, it is possible to suppress adhesion of dust and decrease in workability due to charging (static electricity). Moreover, by bonding the reinforcement film provided with the antistatic layer to the surface of an optical device or an electronic device, the problem resulting from static electricity, such as adhesion of dust to a device, can be reduced.

However, after bonding the reinforcing film to the surface of the adherend, when the pressure-sensitive adhesive layer of the reinforcing film is irradiated with ultraviolet rays to photocur the pressure-sensitive adhesive, the antistatic properties may be deteriorated. In view of such a subject, an object of the present invention is to provide a device having high antistatic properties even after photocuring the pressure-sensitive adhesive layer, and in which a reinforcing film is firmly fixed to the surface of an adherend.

As a result of the present inventors examining in view of the said subject, when an ultraviolet-ray was irradiated to an adhesive layer over the film base material provided with an antistatic layer, it discovered that there existed a tendency for an antistatic layer to deteriorate by the ultraviolet-ray of a short wavelength. Based on these findings, in the method of the present invention, the pressure-sensitive adhesive layer is photocured without irradiating the antistatic layer with ultraviolet light of a short wavelength.

One embodiment of the present invention relates to a reinforcement method for bonding a reinforcement film to the surface of an adherend. A reinforcing film is provided with the photocurable adhesive layer fixedly laminated|stacked on one main surface of a film base material. An antistatic layer containing a conductive polymer and a binder is provided on the back surface of the film substrate. The pressure-sensitive adhesive layer includes a base polymer having a crosslinked structure introduced therein, a photocuring agent having two or more polymerizable functional groups, and a photopolymerization initiator.

After the pressure-sensitive adhesive layer of the reinforcing film is temporarily attached to the surface of the adherend, the pressure-sensitive adhesive layer is photocured by irradiating actinic light to the pressure-sensitive adhesive layer from the second main surface side (antistatic layer formation surface side) of the film substrate. By the photocuring of an adhesive, the adhesive force of a reinforcing film and a to-be-adhered body rises.

When photocuring an adhesive layer, deterioration of an antistatic layer can be suppressed by not irradiating the ultraviolet-ray with a wavelength of 200-280 nm to an antistatic layer. For example, as a light source for photocuring the pressure-sensitive adhesive layer, a light source having substantially no ultraviolet (UVC) light having a wavelength of 200 to 280 nm, such as an LED, a black light, or a chemical lamp, may be used.

The adhesive force between the reinforcing film and the adherend before photocuring the pressure-sensitive adhesive layer is preferably 1N/25mm or less, and the adhesive force between the reinforcing film and the adherend after photocuring the pressure-sensitive adhesive layer is preferably 2N/25mm or more. As for the surface resistance of the 2nd main surface of the film base material after photocuring an adhesive layer, 10 times or less of the surface resistance before photocuring an adhesive layer (before irradiating an actinic light) is preferable.

ADVANTAGE OF THE INVENTION According to this invention, since deterioration of the antistatic layer at the time of photocuring an adhesive layer is suppressed, it has high antistatic property, and the device in which the reinforcing film was firmly fixed to the surface of a to-be-adhered body is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the lamination|stacking structure of a reinforcement film.
Fig. 2 is a cross-sectional view showing a laminated structure of a reinforcing film.
Fig. 3 is a cross-sectional view showing a device having a reinforcing film attached thereto.
4 is a cross-sectional view showing a state in which a reinforcing film having a UVC shielding layer is bonded to the surface of an adherend.
5 is a partial logarithmic graph showing the relationship between light irradiation amount and surface resistance.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the structural example of a reinforcement film. The reinforcement film 5 is equipped with the adhesive layer 2 on one main surface of the film base material 11. As shown in FIG. The pressure-sensitive adhesive layer 2 is adhered to and laminated on the film substrate 11 . The adhesive layer 2 is a photocurable adhesive containing a photocurable composition, it hardens|cures by irradiation of actinic rays, such as an ultraviolet-ray, and adhesive strength with a to-be-adhered body rises. An antistatic layer 12 is provided on the back surface (surface on which the pressure-sensitive adhesive layer 2 is not provided) of the film substrate 11 .

FIG. 2 is a cross-sectional view of a reinforcing film in which a separator 7 is temporarily attached on the main surface of the pressure-sensitive adhesive layer 2 . 3 is a cross-sectional view showing a state in which the reinforcing film 5 is attached to the surface of the device 9 as an adherend.

The reinforcing film 5 on the surface of the device 9 by peeling and removing the separator 7 from the surface of the pressure-sensitive adhesive layer 2 and bonding the exposed surface of the pressure-sensitive adhesive layer 2 to the surface of the device 9 as an adherend. ) is attached and installed. In this state, the pressure-sensitive adhesive layer 2 is before photocuring, and the reinforcing film 5 (the pressure-sensitive adhesive layer 2 ) is temporarily attached on the device 9 . By photocuring the pressure-sensitive adhesive layer 2 , the adhesive force at the interface between the device 9 and the pressure-sensitive adhesive layer 2 increases, and the device 9 and the reinforcing film 5 are in a fixed state.

"Fixed" is a state in which two laminated layers are firmly adhered, and peeling at the interface between them is impossible or difficult. A "temporary adhesion" is a state in which the adhesive force between two laminated|stacked layers is small, and it can peel easily at the interface of both.

In the reinforcing film shown in FIG. 2 , the film base material 11 and the pressure-sensitive adhesive layer 2 are fixed, and the separator 7 is temporarily attached to the pressure-sensitive adhesive layer 2 . When the film base material 11 and the separator 7 are peeled off, peeling occurs at the interface between the pressure-sensitive adhesive layer 2 and the separator 7, and the pressure-sensitive adhesive layer 2 is maintained on the film base material 11. . The adhesive does not remain on the separator 7 after peeling.

As for the device in which the reinforcement film 5 shown in FIG. 3 was attached and provided, before the photocuring of the adhesive layer 2, the device 9 and the adhesive layer 2 are a temporary adhering state. When the film substrate 11 and the device 9 are peeled, peeling occurs at the interface between the pressure-sensitive adhesive layer 2 and the device 9 , and the adhesive layer 2 is maintained on the film substrate 11 . Since the adhesive does not remain on the device 9, rework is easy. Since the adhesive force of the adhesive layer 2 and the device 9 rises after photocuring the adhesive layer 2, it is difficult to peel the film base material 11 from the device 9, and when peeling both, the adhesive Cohesive failure of the layer 2 may occur.

[Composition of reinforcing film]

The reinforcing film 5 has a structure in which the pressure-sensitive adhesive layer 2 is adhered and laminated on the antistatic layer-non-formed side of the film base material 11 (the base material with an antistatic layer 1) provided with the antistatic layer 12 on the back surface. .

<Film substrate>

As the film base material 11, a plastic film is used. In order to fix the film base material 11 and the adhesive layer 2, it is preferable that the release process is not given to the adhesive layer 2 laying surface of the film base material 11.

The thickness of a film base material is about 4-500 micrometers, for example. From a viewpoint of reinforcing a device by rigidity provision, impact relief, etc., 12 micrometers or more are preferable, and, as for the thickness of the film base material 11, 30 micrometers or more are more preferable, and 45 micrometers or more are still more preferable. From a viewpoint of giving flexibility to a reinforcement film and improving handling property, 300 micrometers or less are preferable and, as for the thickness of the film base material 11, 200 micrometers or less are more preferable. From a viewpoint of making mechanical strength and flexibility compatible, 100-3000 kg/cm<2> is preferable, as for the compressive strength of the film base material 11, 200-2900 kg/cm<2> is more preferable, 300-2800 kg/cm<2> is still more preferable, 400 to 2700 kg/cm 2 are particularly preferred.

Examples of the plastic material constituting the film substrate 11 include polyester-based resins, polyolefin-based resins, cyclic polyolefin-based resins, polyamide-based resins, polyimide-based resins, polyetheretherketones, and polyethersulfones. In the reinforcement film for optical devices, such as a display, it is preferable that the film base material 11 is a transparent film. In addition, when photocuring the adhesive layer 2 by irradiating actinic light from the film base material 11 side, the film base material 11 has transparency with respect to the actinic light used for hardening of the adhesive layer 2 . It is preferable to have Polyester-type resin, such as a polyethylene terephthalate, polybutylene terephthalate, and a polyethylene naphthalate, is used suitably from the point which has mechanical strength and transparency.

When photocuring the adhesive layer 2 by irradiating actinic light from the side of the film base material 11, the film base material 11 has transparency with respect to the actinic light used for hardening of the adhesive layer 2 desirable. 60% or more is preferable, as for the transmittance|permeability of the light of wavelength 365nm of the film base material 11, 70 % or more is more preferable, 75 % or more is still more preferable, 80 % or more is especially preferable. 60 % or more is preferable, as for the transmittance|permeability of the light of wavelength 405 nm of the film base material 11, 70 % or more is more preferable, 75 % or more is still more preferable, and 80 % or more is especially preferable.

An antistatic layer 12 is provided on the back surface (opposite side of the pressure-sensitive adhesive layer laying surface) of the film base material 11 . An antistatic layer may be provided also on the adhesive layer laying surface of the film base material 11. Functional coatings, such as an easily bonding layer, a lubrication layer, a mold release layer, a hard-coat layer, and an antireflection layer, may be provided on the surface of a film base material other than an antistatic layer. The antistatic layer 12 may have these functions. As mentioned above, in order to fix the film base material 11 and the adhesive layer 2, it is preferable that the release layer is not provided in the adhesive layer 2 laying surface of the film base material 11.

<Antistatic layer>

By providing the antistatic layer 12 on the back surface of the film base material 11, adhesion of dust to the reinforcing film resulting from charging (static electricity) and the fall of workability|operativity can be suppressed. By providing the antistatic layer on the film substrate, it is possible to suppress peeling electrification that may occur when the reinforcing film is peeled from the adherend for rework or patterning. By providing an antistatic layer, in the manufacturing process of a reinforcing film, the charging which may arise by friction with a conveyance roll, another film, etc. can also be suppressed. Moreover, by providing an antistatic layer, there exists a tendency for slidability to improve, and it can contribute to the improvement of conveyance.

By providing an antistatic layer, peeling electrification at the time of peeling a reinforcement film from a to-be-adhered body for rework or patterning of a reinforcement film can be suppressed. Therefore, electrical destruction of an adherend (eg, an image display panel) caused by static electricity and adhesion of dust to an adherend can be suppressed. As will be explained in detail later, by suppressing the deterioration of the antistatic layer at the time of photocuring the pressure-sensitive adhesive layer, antistatic properties are imparted to the device provided with the reinforcing film. problem can be reduced.

The antistatic layer contains binder resin and a conductive polymer as an antistatic component. As binder resin, various types of resins, such as thermosetting resin, ultraviolet curable resin, electron beam curable resin, and two-component mixed resin, can be employ|adopted. Specific examples of the binder resin include polyester resins, polyurethane resins, acrylic resins, silicone resins, styrene resins, polyamide resins, polyolefin resins, fluorine resins, and alkyd resins. Among these, a polyester-type resin is preferable from a viewpoint, such as improving the slipperiness|lubricacy of a reinforcing film.

Polyester resins are typically polyhydric carboxylic acids having two or more carboxyl groups in one molecule (typically dicarboxylic acids) and derivatives thereof (anhydrides, esters, halides, etc. of the polyhydric carboxylic acids) Polycondensate of at least one compound (polyhydric carboxylic acid component) selected from am.

Examples of the conductive polymer include polyaniline, polyanilinesulfonic acid, polypyrrole, polythiophene, polyethyleneimine, polysulfone, and allylamine polymer. Among them, a composite of poly(3,4-ethylenedioxythiophene) and polystyrenesulfonic acid (PEDOT/PSS) is particularly preferable from the viewpoint of high conductivity and excellent dispersibility in a binder.

The thickness of the antistatic layer is, for example, about 5-200 nm, preferably 10-150 nm, more preferably 15-100 nm, still more preferably 20-70 nm. The surface resistance of the antistatic layer formation surface is, for example, 1×10 ⁸ Ω or less, preferably 1.0×10 ⁷ Ω or less, and more preferably ^{1.0×10 6 Ω or less.} The surface resistance is generally 1.0×10 ³ Ω or more, or 1.0×10 ⁴ Ω or more.

In the formation of the antistatic layer 12 on the film substrate 11, a known coating method such as roll coat, gravure coat, reverse coat, roll brush, spray coat, air knife coat, dip coat and curtain coat may be applied. can After coating, it is preferable that heating is performed for the purpose of removal of a solvent, hardening of a resin component, etc. As a heating method, heating by hot air is mentioned. The heating conditions may be appropriately set according to the composition of the coating layer, the heat resistance of the substrate, and the like, and is usually about 80 to 150° C. for about 10 seconds to 10 minutes. If necessary, for the purpose of accelerating the curing reaction of the resin or the like, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination.

In the manufacturing process of a film base material, you may provide an antistatic layer. For example, a film provided with an antistatic layer on the surface of a film base material can be formed by multilayer co-extrusion. Moreover, you may form an antistatic layer using the heating in the formation process of a film base material. For example, when the film substrate is a stretched film, the composition for forming an antistatic layer is applied to the surface of the film before stretching or the film after vertical stretching, and heating at the time of horizontal stretching or simultaneous biaxial stretching by a tenter is used. , solvent drying or resin curing can be performed.

The antistatic layer contains additives such as lubricants, crosslinking agents, antioxidants, colorants (pigments, dyes, etc.), fluidity regulators (thixotropic agents, thickeners, etc.), film forming aids, surfactants (antifoamers, dispersants, etc.), preservatives, etc. may be included.

<Adhesive layer>

The pressure-sensitive adhesive layer 2 fixedly laminated on the film substrate 11 includes a photocurable composition including a base polymer, a photocuring agent, and a photopolymerization initiator. Since the adhesive layer 2 has small adhesive force with to-be-adhered bodies, such as a device and device components, before photocuring, rework is easy. Since the adhesive layer 2 improves the adhesive force with a to-be-adhered body by photocuring, also at the time of use of a device, a reinforcing film is hard to peel from the device surface, and it is excellent in adhesive reliability.

A photocurable adhesive hardly advances hardening in a general storage environment, and is hardened by irradiation of actinic light, such as an ultraviolet-ray. Therefore, the reinforcement film provided with a photocurable adhesive layer has the advantage that the timing of hardening of the adhesive layer 2 can be set arbitrarily, and it can respond flexibly to the lead time of a process, etc.

(Adhesive strength)

At the time of rework, from the viewpoint of facilitating peeling from the adherend and preventing adhesive residue on the adherend after peeling the reinforcement film, the pressure-sensitive adhesive layer 2 on the glass plate of the reinforcing film before photocuring. The adhesive force is preferably less than 1N/25mm, more preferably 0.8N/25mm or less, still more preferably 0.7N/25mm or less, and particularly preferably 0.6N/25mm or less. From the viewpoint of preventing peeling of the reinforcing sheet from the adherend during storage or handling, the adhesive force of the reinforcing film to the glass plate is preferably 0.03 N/25 mm or more, more preferably 0.05 N/25 mm or more, and 0.1 N/ 25 mm or more is more preferable, and 0.2 N/25 mm or more is especially preferable.

The reinforcing film 5 is in the state before photocuring the adhesive layer 2 WHEREIN: It is preferable that the adhesive force with respect to a polyimide film is in the said range. In a flexible display panel, a flexible printed wiring board (FPC), a device which integrated a display panel and a wiring board, etc., a flexible board|substrate material is used, and a polyimide film is generally used from a viewpoint of heat resistance and dimensional stability. The reinforcing film in which the pressure-sensitive adhesive layer 2 has the above adhesion to the polyimide film as a substrate is easily peeled off before the pressure-sensitive adhesive layer 2 is photocured, and has excellent adhesion reliability after photocuring.

(thickness)

The thickness of the adhesive layer 2 is about 1-300 micrometers, for example. It exists in the tendency for adhesiveness with a to-be-adhered body to improve, so that the thickness of the adhesive layer 2 is large. On the other hand, when the thickness of the adhesive layer 2 is too large, the fluidity|liquidity before photocuring may become 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.

(transparency)

When a reinforcing film is used for optical devices, such as a display, 80 % or more is preferable, as for the total light transmittance of the adhesive layer 2, 85 % or more is more preferable, and 90 % or more is still 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 still more preferable, and 0.5 % or less is especially preferable.

(storage modulus)

The pressure-sensitive adhesive layer 2 preferably has a shear storage modulus G' _i of 1×10 ⁴ to 1.2×10 ⁵ Pa at 25° C. before photocuring. Shear storage modulus (hereinafter simply referred to as "storage modulus") is based on the method described in JIS K7244-1 "Plastic-Dynamic Mechanical Properties Test Method", at a frequency of 1 Hz, at a frequency of -50 to 150°C. It is calculated|required by reading the value in predetermined temperature when measured at the temperature increase rate of 5 degree-C/min in a range.

In a substance exhibiting viscoelasticity such as an adhesive, the storage 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 to the adherend tends to be. When the storage elastic modulus of the pressure-sensitive adhesive layer 2 before photocuring is 1×10 ⁴ Pa or more, the pressure-sensitive adhesive has sufficient hardness and cohesive force, so that when the reinforcing film is peeled off from the adherend, an adhesive residue on the adherend is unlikely to occur. Moreover, when the storage elastic modulus of the adhesive layer 2 is large, the protrusion of the adhesive from the end surface of a reinforcement film can be suppressed. When the storage elastic modulus of the pressure-sensitive adhesive layer 2 before photocuring is 1.2×10 ⁵ Pa or less, peeling at the interface between the pressure-sensitive adhesive layer 2 and the adherend is easy, and even when rework is performed, cohesive failure of the pressure-sensitive adhesive layer or Adhesive residues on the surface of the adherend are less likely to occur. Increase Rework of the reinforcing sheet, in terms of suppressing adhesive residue on the adherend Rework City, stored in 25 ℃ prior to photocuring of the pressure-sensitive adhesive layer (2) elastic modulus G _'i is, 3 × 10 ⁴ to 1×10 ⁵ Pa is more preferable, and 4×10 ⁴ to 9.5×10 ⁴ Pa is still more preferable.

(Furtherance)

The pressure-sensitive adhesive layer 2 is a photocurable composition including a base polymer, a photocuring agent, and a photoinitiator. From a viewpoint of making the adhesiveness of the adhesive layer 2 before photocuring into an appropriate range, it is preferable that the crosslinked structure is introduce|transduced into a base polymer.

(Base Polymer)

The base polymer is the main component 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, it is excellent in optical transparency and adhesiveness, and since control of adhesiveness is easy, it is preferable that the adhesive composition contains an acrylic polymer as a base polymer, It is preferable that 50 weight% or more of the adhesive composition is an acrylic polymer. do.

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

As (meth)acrylic-acid alkylester, the (meth)acrylic-acid alkylester of C1-C20 of an alkyl group is used suitably. The alkyl group of the (meth)acrylic acid alkylester 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, (meth) acrylate pentyl, (meth) acrylate isopentyl, (meth) acrylic acid neopentyl, (meth) acrylate hexyl, (meth) acrylate heptyl, (meth) acrylic acid 2-ethylhexyl, (meth) acrylate octyl, (meth) Isooctyl acrylate, (meth) nonyl acrylate, (meth) acrylate isononyl, (meth) acrylate decyl, (meth) acrylate isodecyl, (meth) acrylate undecyl, (meth) acrylate dodecyl, (meth) acrylic acid iso Tridodecyl, (meth)acrylic acid tetradecyl, (meth)acrylic acid isotetradecyl, (meth)acrylic acid pentadecyl, (meth)acrylic acid cetyl, (meth)acrylic acid heptadecyl, (meth)acrylic acid octadecyl, (meth) Acrylic acid isooctadecyl, (meth)acrylic acid nonadecyl, (meth)acrylic acid aralkyl, etc. are mentioned.

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

It is preferable that a 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 hydroxyl group-containing monomer and a carboxyl group-containing monomer. A base polymer may have both a hydroxyl group containing monomer and a carboxy group containing monomer, and may have only either one as a monomer component. A hydroxy group or a carboxy group of the base polymer serves as a reaction point with a crosslinking agent described later. For example, when using an isocyanate type 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 carboxyl group-containing monomer as a copolymerization component of a base polymer. 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 to the adherend at the time of rework tends to decrease.

As the hydroxyl group-containing monomer, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 4-hydroxybutyl, (meth)acrylic acid 6-hydroxyhexyl, (meth)acrylic acid 8 -hydroxyoctyl, (meth)acrylic acid 10-hydroxydecyl, (meth)acrylic acid 12-hydroxylauryl, (meth)acrylic acid 4-(hydroxymethyl)cyclohexylmethyl, etc. are mentioned. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, (meth)acrylic acid 2-carboxyethyl, carboxypentyl (meth)acrylic acid carboxypentyl, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

In the base polymer, the total amount of the hydroxyl group-containing monomer and the carboxyl group-containing monomer relative to the total amount of the constituent monomer components is preferably 1 to 30% by weight, more preferably 3 to 25% by weight, more preferably 5 to 20% by weight. desirable.

The base polymer, as a constituent monomer component, is N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxa. Nitrogen-containing monomers, such as sol, vinyl morpholine, N-acryloyl morpholine, N-vinyl carboxylic acid amides, and N-vinyl caprolactam, may be contained.

The base polymer may contain monomer components other than the above. For example, the acrylic base polymer includes, as a monomer component, 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, etc. may be included.

100,000-5 million are preferable, as for the weight average molecular weight of a base polymer, 300,000-3 million are more preferable, 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 crosslinked structure introduction.

There exists a tendency for an adhesive to become hard, so that there is much content of the high Tg monomer component in the structural component of a base polymer. In addition, a high Tg monomer means a monomer with a high glass transition temperature (Tg) of a homopolymer. As a monomer whose Tg of a homopolymer is 40 degreeC or more, dicyclofentanyl methacrylate (Tg: 175 degreeC), dicyclopentanyl acrylate (Tg: 120 degreeC), isobornyl methacrylate (Tg: 173 degreeC), iso Bornyl acrylate (Tg: 97 °C), methyl methacrylate (Tg: 105 °C), 1-adamantyl methacrylate (Tg: 250 °C), 1-adamantyl acrylate (Tg: 153 °C) (meth)acrylic monomers such as; Acryloylmorpholine (Tg: 145°C), dimethylacrylamide (Tg: 119°C), diethylacrylamide (Tg: 81°C), dimethylaminopropylacrylamide (Tg: 134°C), isopropylacrylamide ( amide group-containing vinyl monomers such as Tg: 134° C.) and hydroxyethyl acrylamide (Tg: 98° C.); acid monomers such as methacrylic acid (Tg: 228°C) and acrylic acid (Tg: 106°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 of a base polymer is 1-50 weight% with respect to the total amount of structural monomer components, and, as for a base polymer, it is more preferable that it is 3-40 weight%. In order to form a pressure-sensitive adhesive layer having suitable hardness and excellent reworkability, as a monomer component of the base polymer, it is preferable to include a monomer component having a Tg of 80°C or higher of the homopolymer, and a monomer component having a Tg of 100°C or higher of the homopolymer. It is more preferable to include In the base polymer, the content of the monomer having a Tg of 100° C. or higher 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, still more preferably 1% by weight or more, 3 It is especially preferable that it is weight % or more.

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. From viewpoints of balance of characteristics, such as the adhesive force of an adhesive and holding|maintenance force, cost, etc., the solution polymerization method is preferable. As a solvent for solution polymerization, ethyl acetate, toluene, etc. are used. 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 type and a peroxide type, can be used. In order to adjust the molecular weight, a chain transfer agent may be used. The reaction temperature is usually about 50 to 80°C, and the reaction time is usually about 1 to 8 hours.

(crosslinking agent)

From the viewpoint of giving the pressure-sensitive adhesive a suitable cohesive force, it is preferable that a crosslinked structure is introduced into the base polymer. For example, a crosslinking structure is introduced by adding a crosslinking agent to the solution after polymerization of the base polymer and heating as necessary. As a crosslinking agent, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an oxazoline type crosslinking agent, an aziridine type crosslinking agent, a carbodiimide type crosslinking agent, a metal chelate type crosslinking agent, etc. are mentioned. These crosslinking agents react with functional groups, such as a hydroxy group and a carboxy group, introduced into the base polymer to form a crosslinked structure. An isocyanate-based crosslinking agent and an epoxy-based crosslinking agent are preferable from the viewpoint of high reactivity with a hydroxy group or a carboxyl group of the base polymer and easy introduction of a crosslinked structure.

As the isocyanate-based crosslinking agent, a polyisocyanate having two or more isocyanate groups in one molecule is used. As an isocyanate type crosslinking agent, For example, Lower aliphatic polyisocyanate, 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., dosing agent "Coronate L"), trimethylolpropane/hexamethylene diisocyanate trimer adduct (e.g., dosing agent "Coronate HL") , a trimethylolpropane adduct of xylylene diisocyanate (for example, "Takenate D110N" manufactured by Mitsui Chemicals), an isocyanurate body of hexamethylene diisocyanate (for example, "Coronate HX" manufactured by Tosoh), etc. of isocyanate adducts, and the like.

As the epoxy-based crosslinking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule is used. A glycidyl group may be sufficient as the epoxy group of an epoxy-type crosslinking agent. Examples of the epoxy-based crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, and 1,3-bis(N,N-diglycidylaminomethyl). ) Cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, poly Propylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane Polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol- S-diglycidyl ether etc. are mentioned. As an epoxy-type crosslinking agent, you may use commercial items, such as "Denacol" manufactured by Nagase Chemtex, and "Tetrad X" and "Tetrad C" manufactured 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 amount of the crosslinking agent used is about 0.01 to 10 parts by weight based on 100 parts by weight of the base polymer, preferably 0.1 to 7 parts by weight, more preferably 0.2 to 6 parts by weight, and still more preferably 0.3 to 5 parts by weight. . Further, the value obtained by dividing the amount of the crosslinking 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 crosslinking agent is preferably 0.00015 to 0.11, more preferably 0.001 to 0.077, and 0.003 to 0.055 More preferably, 0.0045 to 0.044 are particularly preferable. By increasing the amount of the crosslinking agent used for the purpose of permanent adhesion and giving the adhesive a suitable hardness, the adhesive residue on the adherend at the time of rework is reduced and the reworkability is improved. There is this.

In order to promote formation of a crosslinked structure, a crosslinking catalyst may be used. For example, as a crosslinking catalyst of an isocyanate-based crosslinking agent, tetra-n-butyl titanate, tetraisopropyl titanate, ferric nases, butyltin oxide, dioctyltin dilaurate, dibutyltin dilaurate, etc. A metal-type crosslinking catalyst (particularly a tin type crosslinking catalyst) etc. are mentioned. 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 pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 2 contains a photocuring agent in addition to the base polymer. When the adhesive layer 2 containing a photocurable adhesive composition photocures after bonding with a to-be-adhered body, adhesive force with a to-be-adhered body will improve.

As the photocuring agent, a photocurable monomer having two or more polymerizable functional groups in one molecule or a photocurable oligomer is used. The photocuring agent is preferably a compound having an ethylenically unsaturated bond such as a vinyl group or a (meth)acryloyl group as a polymerizable functional group. Moreover, as for a photocuring agent, the compound which shows compatibility with a base polymer is preferable. From the viewpoint of showing suitable compatibility with the base polymer, the photocuring agent is preferably a liquid at room temperature.

The compatibility of the base polymer and the photocuring agent is mainly affected 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 tends to be.

It is preferable to use a polyfunctional (meth)acrylate as a photocuring agent at a point with high compatibility with an acryl-type base polymer. Examples of the polyfunctional (meth)acrylate include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and 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 Tri (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylol propane tri (meth) acrylate, ditrimethylol propane tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, pentaerythritol 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. are mentioned.

The compatibility of the base polymer and the photocuring agent also depends on the molecular weight of the compound. The lower the molecular weight of the photocurable compound, the higher the compatibility with the base polymer tends to be. From a viewpoint of compatibility with a base polymer, 1500 or less are preferable and, as for the molecular weight of a photocuring agent, 1000 or less are more preferable.

The kind and content of the photocuring agent affect the adhesive force after photocuring. The adhesive force after photocuring tends to become large, so that the functional group equivalent is small (that is, the functional group number per unit molecular weight is large) and content of a photocuring agent is large. From a viewpoint of raising the adhesive force after photocuring, 500 or less are preferable and, as for the functional group equivalent (g/eq) of a photocuring agent, 450 or less are more preferable. On the other hand, when the photocrosslinking density is excessively increased, the viscosity of the pressure-sensitive adhesive may be lowered and the adhesive force may be lowered. Therefore, 100 or more are preferable, as for the functional group equivalent of a photocuring agent, 130 or more are more preferable, and 150 or more are still more preferable.

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, and the adhesive force (initial adhesion) of the pressure-sensitive adhesive before photocuring increases. there is An excessive increase in initial adhesive force may lead to a fall of rework property. 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 to-be-adhered body in an appropriate range.

10-50 weight part is preferable with respect to 100 weight part of base polymers, as for content of the photocuring agent in an adhesive composition, 13-45 weight part is more preferable, 15-40 weight part is still more preferable. When a photocurable compound is contained in an adhesive composition as a non-hardened monomer or oligomer, the photocurable adhesive layer 2 is obtained. In order to include the photocuring agent in an uncured state in the composition, it is preferable to add the photocuring agent to the polymer solution after polymerizing the base polymer.

(Photoinitiator)

A photoinitiator generates active species by irradiation of actinic light, and accelerates|stimulates the hardening reaction of a photocuring agent. As a photoinitiator, a photocationic initiator (photoacid generator), a photoradical initiator, a photoanion initiator (photobase generator), etc. are used according to the kind etc. of a photocuring agent. When ethylenically unsaturated compounds, such as polyfunctional acrylate, are used as a photocuring agent, it is preferable to use a photoradical initiator as a polymerization initiator.

A photoradical initiator produces|generates a radical by irradiation of actinic light, and accelerates|stimulates the radical polymerization reaction of a photocuring agent by radical transfer from a photoradical initiator to a photocuring agent. As a photoradical initiator (photoradical generator), it is preferable to generate|occur|produce a radical by irradiation of visible light or ultraviolet-ray with a wavelength shorter than 450 nm, hydroxy ketones, benzyl dimethyl ketals, amino ketones, acyl phosphine oxides, benzo phenones, trichloromethyl group-containing triazine derivatives, and the like. A photoradical initiator may be used independently and may mix and use 2 or more types.

When transparency is requested|required for the adhesive layer 2, it is preferable that the sensitivity with respect to the light (visible light) of a wavelength longer than 400 nm of a photoinitiator is small, for example, the extinction coefficient in wavelength 405 nm is 1x10 ² [mLg] ^-1 cm ^-1 ] or less of a photopolymerization initiator is preferably used.

0.01-5 weight part is preferable with respect to 100 weight part of base polymers, as for content of the photoinitiator in the adhesive layer 2, 0.02-3 weight part is more preferable, 0.03-2 weight part is still more preferable. 0.02-10 weight part is preferable with respect to 100 weight part of photocuring agents, as for content of the photoinitiator in the adhesive layer 2, 0.05-7 weight part is more preferable, 0.1-5 weight part is still more preferable.

(Other additives)

In addition to each component exemplified above, the pressure-sensitive adhesive layer 2 contains additives such as a silane coupling agent, a tackifier, a plasticizer, a softener, an anti-degradation agent, a filler, a colorant, an ultraviolet absorber, an antioxidant, a surfactant, an antistatic agent, and the like there may be

[Production of reinforcing film]

By laminating the photocurable adhesive layer 2 on the film base material 11, a reinforcement film is obtained. From a viewpoint of productivity, it is preferable to laminate|stack the adhesive layer 2 on the antistatic layer non-formation surface of the film base material 11 (substrate with an antistatic layer 1) which provided the antistatic layer 12 beforehand. The pressure-sensitive adhesive layer 2 may be directly formed on the film base material 11 , or the pressure-sensitive adhesive layer formed in a sheet shape on another base material may be transferred onto the film base material 11 .

The pressure-sensitive adhesive composition is applied onto the substrate 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. A pressure-sensitive adhesive layer is formed by applying to and removing the solvent by drying if necessary. As the drying method, an appropriately suitable method may be employed. Heat drying temperature becomes like this. Preferably it is 40 degreeC - 200 degreeC, More preferably, it is 50 degreeC - 180 degreeC, More preferably, it is 70 degreeC - 170 degreeC. 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.

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 heating time are suitably set according to the kind of crosslinking agent to be used, and bridge|crosslinking is performed by heating for about 1 minute to 7 days in the range of normally 20 degreeC - 160 degreeC. The heating for drying and removing a solvent may serve also as the heating for bridge|crosslinking.

By introducing a crosslinked structure into the base polymer, the gel fraction is increased. The higher the gel fraction, the harder the pressure-sensitive adhesive, and when the reinforcing film is peeled from the adherend by rework or the like, the adhesive residue on the adherend tends to be suppressed. The gel fraction before photocuring of the pressure-sensitive adhesive layer 2 may be 30% or more or 50% or more. The gel fraction before photocuring is preferably 60% or more, more preferably 65% or more, and still more preferably 70% or more. The gel fraction may be 75% or more. When the gel fraction before photocuring of the pressure-sensitive adhesive layer 2 is excessively large, the anchoring force to the adherend may be lowered, and the initial adhesive force may become insufficient. Therefore, 95 % or less is preferable, as for the gel fraction before photocuring of the adhesive layer 2, 90 % or less is more preferable, 85 % or less is still more preferable, and 80 % or less is especially preferable. The gel fraction can be calculated as an insoluble content in a solvent such as ethyl acetate, and specifically, the weight fraction of the insoluble component after immersing the pressure-sensitive adhesive layer in ethyl acetate at 23° C. for 7 days relative to the sample before immersion (unit: weight) %). In general, the gel fraction of a polymer is equivalent to the degree of crosslinking, and the more crosslinked parts in the polymer, the greater the gel fraction.

Even after the crosslinking structure is introduced into the polymer by the crosslinking agent, the photocuring agent maintains 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 11, it is preferable to lay the separator 7 on the adhesive layer 2 for the purpose of protection of the adhesive layer 2, etc. After laying the separator 7 on the adhesive layer 2, you may bridge|crosslink.

When forming the adhesive layer 2 on another base material, a reinforcement film is obtained by transcribe|transferring the adhesive layer 2 on the film base material 11, after drying a solvent. It is good also considering the base material used for formation of an adhesive layer as the separator 7 as it is.

[Use of reinforcing film]

<Bonding of reinforcing film to adherend>

The reinforcing film is used by bonding to a device or device component. Since moderate rigidity is provided by bonding a reinforcement film, the handling property improvement and the damage prevention effect are anticipated. In the manufacturing process of a device, when a reinforcement film is bonded to a work-in-work, you may bond a reinforcement film to the work-in-work of a wide surface before it cut|disconnects to a product size. You may bond a reinforcement film to the mother roll of the device manufactured by a roll-to-roll process by roll-to-roll.

Since the antistatic layer 12 is provided on the back surface of the film base material 11, adhesion of dust resulting from the charging at the time of roll conveyance can be suppressed. Moreover, by providing the antistatic layer 12, there exists a tendency for slidability to improve. Therefore, while the conveyance and winding property of a film improve, blocking at the time of winding up in roll shape can be suppressed.

The adherend to which the reinforcing film is bonded is not particularly limited, and examples thereof include various electronic devices, optical devices, and constituent parts thereof. The thickness of the member which comprises a device tends to become small with high integration of a device, size reduction, and thickness reduction. Due to the reduction in thickness of the structural member, the curvature or curl caused by the stress at the lamination interface or the like tends to occur. Moreover, it becomes easy to produce the curvature by dead weight by thickness reduction. Since rigidity can be provided to a to-be-adhered body by bonding a reinforcing film, curvature, curl, curvature, etc. by stress, dead weight, etc. are suppressed, and handling property improves. Therefore, by bonding a reinforcing film to a work-in-process in the device manufacturing process, defects and problems at the time of conveyance or processing by an automated apparatus can be prevented.

The reinforcing film 5 may be bonded to the entire surface of the adherend 9, or may be selectively bonded only to a portion requiring reinforcement. Moreover, after bonding a reinforcement film to the whole surface of a to-be-adhered body, you may cut|disconnect the reinforcement film at the location which does not require reinforcement, and peel and remove a reinforcement film from the surface of a to-be-adhered body. After the pressure-sensitive adhesive is cured by selectively irradiating light to a portion requiring reinforcement, the reinforcing film at a portion not irradiated with light may be peeled off and removed from the adherend. Before the photocuring of the pressure-sensitive adhesive layer 2 , the reinforcing film 5 can be easily peeled off from the surface of the adherend 9 because the reinforcing film is in a state of being temporarily attached to the surface of the adherend.

<Photocuring of the adhesive layer>

After bonding the reinforcing film 5 to the adherend 9, a light source (not shown) disposed on the antistatic layer-equipped substrate 1 side (upper side in Fig. 3) is applied to the pressure-sensitive adhesive layer 2 with ultraviolet rays or the like. By irradiating actinic light, the pressure-sensitive adhesive layer 2 is photocured. By photocuring the pressure-sensitive adhesive layer 2 , the reinforcing film 5 is firmly adhered to the adherend 9 . Even when an external force is suddenly applied due to a fall of the device, loading of a heavy object onto the device, collision of flying objects on the device, or the like, damage to the device can be prevented by bonding the reinforcing film. In addition, since the base material 1 with an antistatic layer is firmly adhered to the surface of the adherend 9 through the pressure-sensitive adhesive layer 2 containing the photocured material of the photocurable pressure-sensitive adhesive composition, the reinforcing film is It is hard to peel, and it is excellent in reliability.

When photocuring the adhesive layer 2 and irradiating actinic light to the adhesive layer 2 from the light source located at the base material 1 side with an antistatic layer, actinic light will be irradiated also to the antistatic layer 12. When ultraviolet light of a short wavelength such as UVC (wavelength 200 to 280 nm) is irradiated to the antistatic layer containing a conductive polymer, the antistatic performance tends to decrease. Therefore, it is preferable to photocurate an adhesive layer so that the ultraviolet-ray with a wavelength of 200-280 nm may not be irradiated to an antistatic layer.

The intensity (irradiance) of ultraviolet rays with a wavelength of 200 to 280 nm irradiated to the antistatic layer is preferably 20 μW/cm 2 or less, more preferably 10 μW/cm 2 or less, still more preferably 5 μW/cm 2 or less, and 1 μW/cm 2 or less. Especially preferred. The irradiance of ultraviolet rays of 200 to 280 nm to the antistatic layer is ideally zero.

For example, when a light source which does not contain the ultraviolet-ray with a wavelength of 200-280 nm substantially is used as a light source at the time of photocuring an adhesive layer, deterioration of an antistatic layer can be suppressed. As a light source whose emitted light does not contain the ultraviolet-ray with a wavelength of 200-280 nm substantially, LED, a black light, a chemical lamp, etc. are mentioned. When using LED, in order to photocure an adhesive layer efficiently, suppressing deterioration of an antistatic layer, it is preferable that the range of an emission peak wavelength is 300-450 nm. What is necessary is just to select suitably the light emission peak wavelength of LED according to the absorption wavelength etc. of the photoinitiator contained in an adhesive layer, and you may use combining several LED which has different light emission peak wavelength.

From the viewpoint of enhancing the efficiency of photocuring, the irradiance of light having a wavelength of 300 to 450 nm at the time of photocuring the pressure-sensitive adhesive layer is preferably 10mW/cm2 or more, more preferably 20mW/cm2 or more, and still more preferably 30mW/cm2 or more. do. What is necessary is just to select an integrated irradiation amount so that photocuring of an adhesive may fully advance, and is 100 mJ/cm<2> or more, for example. The cumulative irradiation amount of light having a wavelength of 300 to 450 nm may be 300 mJ/cm 2 or more, 500 mJ/cm 2 or more, 700 mJ/cm 2 or more, 1000 mJ/cm 2 or more, or 1500 mJ/cm 2 or more.

2N/25mm or more is preferable, as for the adhesive force of the reinforcement film after photocuring an adhesive layer, and to-be-adhered body, 3N/25mm or more is more preferable, 5N/25mm or more is still more preferable. The adhesive force between the reinforcing film and the adherend after photocuring the pressure-sensitive adhesive layer may be 6N/25mm or more, 8N/25mm or more, 10N/25mm or more, 12N/25mm or more, or 13N/25mm or more. 5 times or more of the adhesive force of the adhesive layer and to-be-adhered body before photocuring is preferable, 8 times or more are more preferable, and, as for the adhesive force of the adhesive layer and to-be-adhered body after photocuring, 10 times or more are still more preferable. The adhesive force between the pressure-sensitive adhesive layer and the adherend after photocuring may be 20 times or more, 30 times or more, 40 times or more, or 50 times or more of the adhesive force between the pressure-sensitive adhesive layer and the adherend before photocuring.

^{1×10 8} Ω or less is preferable and, as for the surface resistance of the antistatic layer 12 formation surface of the base material 1 after photocuring an adhesive layer ^{, 1.0×10 7} Ω or less is more preferable. The surface resistance of the antistatic layer 12 formation surface of the base material 1 after photocuring the pressure-sensitive adhesive layer ^{may be 1.0×10 6} Ω or less. The surface resistance of the antistatic layer formation surface after photocuring the pressure-sensitive adhesive layer is preferably 10 times or less of the surface resistance before photocuring the pressure-sensitive adhesive layer (before irradiating actinic light to the pressure-sensitive adhesive layer over the film substrate), and 5 times The following is more preferable, 3 times or less is still more preferable, and 2 times or less is especially preferable. As mentioned above, by suppressing irradiation of short-wavelength ultraviolet rays, such as UVC, to an antistatic layer, deterioration of an antistatic layer can be suppressed and an increase in surface resistance can be suppressed.

As a method of preventing the irradiation of ultraviolet rays with a wavelength of 200 to 280 nm to the antistatic layer, in addition to the method of selecting a light source, there is a method of shielding the ultraviolet rays with a wavelength of 200 to 280 nm emitted from the light source from reaching the antistatic layer. For example, even when a light source containing UVC is used for the radiation of a low pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, etc., by placing a UVC shielding material that absorbs and/or reflects UVC between the light source and the reinforcing film , deterioration by UVC irradiation to the antistatic layer can be suppressed.

For example, as shown in FIG. 4 , on the surface of the antistatic layer 12 , in a state where a UVC shielding layer 17 that absorbs and/or reflects ultraviolet rays having a wavelength of 200 to 280 nm is disposed, actinic light is irradiated Thus, the pressure-sensitive adhesive layer 2 may be photocured. Examples of the UVC shielding layer include a resin material that absorbs UVC, glass, a band-pass filter, a cut-off filter (long-pass filter), and the like. What is necessary is just to remove the UVC shielding layer 17 after photocuring of an adhesive layer.

The UVC shielding material does not need to be disposed in contact with the antistatic layer, and may be disposed between the light source and the antistatic layer. Moreover, you may use a UVC shielding material for the constituent material of a light source. For example, in an ultraviolet source such as a high-pressure mercury lamp, quartz is generally used for a light emitting tube, but UVC may be shielded by substituting this with soda-lime glass, borosilicate glass, or the like.

Example

EXAMPLES Hereinafter, although embodiment of this invention is described in more detail with reference to an Example, this invention is not limited to the following Example.

[Production of reinforcing film]

<Preparation of a film base material with an antistatic layer>

The components of the following (A) to (D) were added to a mixed solvent of water and ethanol, and stirred and mixed for about 20 minutes to prepare an antistatic treatment solution having a solid content of about 0.3%.

(A) Aqueous solution containing 0.5% of poly(3,4-ethylenedioxythiophene) and 0.8% of polystyrenesulfonate (number average molecular weight 150,000) as conductive polymer (“Clevios P” manufactured by Heraeus): 50 parts by weight by solid content

(B) 25% aqueous dispersion of saturated copolymerized polyester resin (“Binarol MD-1480” manufactured by Toyobo): 100 parts by weight by solid content

(C) Aqueous dispersion of carnauba wax: 40 parts by weight by solid content (as lubricant)

(D) Melamine-based crosslinking agent: 10 parts by weight

On one side of a 75 µm-thick polyethylene terephthalate film (“Lumiror S10-75” manufactured by Toray Industries, Ltd.) that has not been surface-treated, the treatment solution is applied with a bar coater, dried by heating at 130° C. for 30 seconds, and the thickness An antistatic layer of 40 nm was formed.

<Formation of adhesive layer>

In a reaction vessel equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube, 95 parts by weight of butyl acrylate and 5 parts by weight of acrylic acid as a monomer, 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, And 233 weight part of ethyl acetate was thrown in as a solvent, nitrogen gas was flowed, and nitrogen substitution was performed for about 1 hour, stirring. Then, it heated to 60 degreeC, it was made to react for 7 hours, and the solution of the acrylic polymer with a weight average molecular weight of 600,000 was obtained.

In an acrylic polymer solution, 0.5 parts by weight of a tetrafunctional epoxy compound (“Tetrad C” manufactured by Mitsubishi Gas Chemical) as a crosslinking agent, “A-200” manufactured by Shin-Nakamura Chemical Co., Ltd. as a polyfunctional acrylic monomer (polyethylene glycol #200 (polyethylene glycol #200) n = 4) diacrylate, molecular weight 308, functional group equivalent 154 g/eq) 30 parts by weight, and 1 part by weight of a photopolymerization initiator (“Irgacure 651” manufactured by BASF) were added and mixed uniformly to prepare a pressure-sensitive adhesive composition .

The pressure-sensitive adhesive composition was applied to the non-static layer-non-formed surface of the film substrate using a fountain roll so that the thickness after drying was set to 25 µm. After drying at 130° C. for 1 minute to remove the solvent, the release-treated surface of a separator (a 25 µm-thick polyethylene terephthalate film having a silicone release-treated surface) was bonded to the coated surface of the pressure-sensitive adhesive. Then, the aging process for 4 days was performed in 25 degreeC atmosphere, crosslinking was advanced, the photocurable adhesive layer fixedly laminated|stacked on the film base material, and the reinforcement film by which the separator was temporarily attached was obtained.

[Joining to an adherend and photocuring of the adhesive]

A 12.5 µm-thick polyimide film (“Kapton 50EN” manufactured by Toray DuPont) was affixed to a glass plate via a double-sided adhesive tape (“No.531” manufactured by Nitto Denko) to obtain a test substrate. The separator was peeled off from the surface of the reinforcing film cut to a width of 25 mm x a length of 100 mm, and bonded to the polyimide film of the test substrate using a hand roller, and UV rays were irradiated from the reinforcing film side (antistatic layer formation surface of the film substrate). Thus, the pressure-sensitive adhesive layer was photocured.

As the ultraviolet source, an LED light source having a wavelength of 365 nm in Example 1, a black light in Example 2, and a high-pressure mercury lamp in Comparative Example 1 were used. In each example, irradiation time was adjusted so that the accumulated light amount of actinic light with a wavelength of 290-430 nm might be 2000 J/cm<2>, 4000 mJ/cm<2>, or 8000 mJ/cm<2>, and the adhesive layer was photocured.

[evaluation]

<Surface resistance>

For each of the sample immediately after bonding to the test substrate (before UV irradiation) and the sample after photocuring the pressure-sensitive adhesive layer by UV irradiation, under an environment of a temperature of 23° C. and a relative humidity of 50%, a resistivity meter (manufactured by TREK “ Model 152-1"), the probe ("Model 152P-2P" manufactured by TREK) was brought into contact with the surface (antistatic layer) of the film substrate, and the surface resistance was measured under the conditions of an applied voltage of 10 V and a voltage application time of 10 seconds. did.

<Adhesiveness>

With respect to the sample immediately after bonding to the test substrate (before UV irradiation), and the sample in which the pressure-sensitive adhesive layer was photocured by UV irradiation with an accumulated light amount of 8000 mJ/cm 2 , the end of the reinforcing film is held with a chuck, and the tensile rate is 300 mm/ A 180 degree peel test was performed in minutes, and the test force of the peel test was made into adhesive force.

<Evaluation result>

Fig. 5 shows a logarithmic graph in which the relationship between the light irradiation amount (accumulated light amount) and the surface resistance in Examples and Comparative Examples is plotted. In addition, Table 1 shows the antistatic layer surface resistance and adhesive force after irradiating 8000 mJ/cm 2 of ultraviolet rays, and the increase rate before and after irradiation. In addition, the surface resistance before irradiation with ultraviolet rays was 1.5 × 10 ⁵ Ω, and the adhesive force was 0.16 N/25 mm.

Even when any light source was used, the adhesive force after irradiating 8000 mJ/cm 2 of actinic light increased more than 80 times before UV irradiation, and the adhesive was photocured, so it can be seen that the reinforcing film is firmly adhered to the polyimide film. .

In Comparative Example 1 in which the pressure-sensitive adhesive layer was photocured using a high-pressure mercury lamp, it was found that the surface resistance increased significantly with the increase in the amount of irradiation light, and the antistatic layer was deteriorated by ultraviolet irradiation. In contrast, in Examples 1 and 2 using a light source that does not contain short-wavelength ultraviolet light, it can be seen that the change in surface resistance is small even after the pressure-sensitive adhesive is photocured, and the antistatic performance is maintained.

From the above results, using a light source that does not substantially contain ultraviolet light of a short wavelength, by performing light irradiation to the pressure-sensitive adhesive layer over the antistatic layer-equipped substrate, it is possible to photocur the pressure-sensitive adhesive while suppressing deterioration of the antistatic layer, It can be seen that a device having excellent antistatic properties and a reinforcing film firmly adhered to an adherend can be obtained.

1: Substrate with antistatic layer
11: Film substrate
12: antistatic layer
2: adhesive layer
5: Reinforcement film
7: Separator
9: adherend
17: UVC shielding layer

Claims (10)

A method for manufacturing a device in which a reinforcing film is bonded to the surface,
Preparing a reinforcing film comprising a film substrate having a first main surface and a second main surface, and a photocurable pressure-sensitive adhesive layer fixedly laminated on one main surface of the film substrate,
After the pressure-sensitive adhesive layer of the reinforcing film is attached to the surface of the adherend,
a step of raising the adhesive force between the reinforcing film and the adherend by irradiating actinic light to the pressure-sensitive adhesive layer from a light source located on the second main surface side of the film substrate to photocur the pressure-sensitive adhesive layer;
An antistatic layer comprising a conductive polymer and a binder is provided on the second main surface of the film substrate,
The pressure-sensitive adhesive layer includes a base polymer having a crosslinked structure introduced therein, a photocuring agent having two or more polymerizable functional groups, and a photopolymerization initiator,
When the pressure-sensitive adhesive layer is photocured, the antistatic layer is not irradiated with ultraviolet rays having a wavelength of 200 to 280 nm, a method of manufacturing a device. The method of claim 1 , wherein when the pressure-sensitive adhesive layer is photocured, light emitted from the light source substantially does not contain ultraviolet light having a wavelength of 200 to 280 nm. The manufacturing method of the device of Claim 1 or 2 whose surface resistance of the 2nd main surface of the said film base material after irradiating actinic light to the said adhesive layer is 10 times or less of the surface resistance before irradiating actinic light. The method for manufacturing a device according to any one of claims 1 to 3, wherein the adhesive force between the reinforcing film and the adherend before irradiating the pressure-sensitive adhesive layer with actinic light is 1 N/25 mm or less. The method for manufacturing a device according to any one of claims 1 to 4, wherein the adhesive force between the reinforcing film and the adherend after irradiating the pressure-sensitive adhesive layer with actinic light is 2N/25 mm or more. The method for manufacturing a device according to any one of claims 1 to 5, wherein the gel fraction of the pressure-sensitive adhesive layer before photocuring is 60% or more. The method for manufacturing a device according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive layer before photocuring contains 10 to 50 parts by weight of the photocuring agent with respect to 100 parts by weight of the base polymer. It is a device with a reinforcing film bonded to the surface,
The reinforcing film includes a film substrate having a first main surface and a second main surface, and an adhesive layer fixedly laminated on one main surface of the film substrate,
The pressure-sensitive adhesive layer of the reinforcing film is bonded to the surface of the device,
An antistatic layer comprising a conductive polymer and a binder is provided on the second main surface of the film substrate,
The pressure-sensitive adhesive layer is a photocuring reaction product of a composition including a base polymer having a crosslinked structure introduced therein, a photocuring agent having two or more polymerizable functional groups, and a photopolymerization initiator,
The adhesive strength between the reinforcing film and the adherend is 2N/25mm or more,
The device, wherein the surface resistance of the second main surface of the film substrate is 1.0×10 ⁷ Ω or less. It is a reinforcing method of bonding a reinforcing film to the surface of an adherend,
Preparing a reinforcing film comprising a film substrate having a first main surface and a second main surface, and a photocurable pressure-sensitive adhesive layer fixedly laminated on one main surface of the film substrate,
After the pressure-sensitive adhesive layer of the reinforcing film is attached to the surface of the adherend,
a step of raising the adhesive force between the reinforcing film and the adherend by irradiating actinic light to the pressure-sensitive adhesive layer from a light source located on the second main surface side of the film substrate to photocur the pressure-sensitive adhesive layer;
An antistatic layer comprising a conductive polymer and a binder is provided on the second main surface of the film substrate,
The pressure-sensitive adhesive layer includes a base polymer having a crosslinked structure introduced therein, a photocuring agent having two or more polymerizable functional groups, and a photopolymerization initiator,
When the pressure-sensitive adhesive layer is photocured, the antistatic layer is not irradiated with ultraviolet rays having a wavelength of 200 to 280 nm, a reinforcement method. 10. The method of claim 9, wherein when the pressure-sensitive adhesive layer is photocured, the light emitted from the light source is substantially free of ultraviolet light having a wavelength of 200 to 280 nm.

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