JPS61101582A - Manufacture or electrical part - Google Patents

Abstract

PURPOSE:To firmly bond a transparent film for a diaphragm etc. to the body of an electrical part such as a speaker without forming any crease, by setting a specified photo-setting, sheet-like self-adhesive by light irradiation after the film is attached to the body across the adhesive. CONSTITUTION:An acrylic polymer emulsion particle of double layer structure is prepd. by two-stage emulsion polymn. using an unsaturated monomer such as ethyl acrylate. Then a monomer such as N-methylolacrylamide having a photo-setting unsaturated group is added to the outer layer of the particle via a covalent linkage to prepare an acrylic photo-crosslinkable polymer emulsion having film-forming ability. Then the polymer emulsion is compounded with a photosensitizer such as benzoin and molded in the form of a tape or sheet. A transparent film for a diaphragm etc., is attached to the body of an electrical part such as a speaker across the obtd. self-adhesive and bonded to the body by curing the adhesive by irradiation with light.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing an electrical component using a light-transmitting film as an assembly component, such as a speaker using a polyester film as a diaphragm.

[Conventional technology]

2. Description of the Related Art Thin plastic films such as polyester films with a thickness of about 10 to 100 μm are often used as diaphragms for speakers, which are one of the electrical components in audio equipment. In order for this plastic film to fully demonstrate its performance as a diaphragm, it is necessary to ensure that there are no wrinkles or other deformations at the bonded part of the plastic film to the speaker body, and that the speaker assembly be properly bonded to the speaker body so that the plastic film does not peel off due to vibration. It is necessary to firmly adhere to the main body.

Conventionally, liquid adhesives such as solvent-containing adhesives, emulsion adhesives, and moisture-curing seven-point adhesives such as cyanoacrylate have been used to bond the above-mentioned plastic film and the speaker body. However, because the film is thin, the bonded parts of the film tend to wrinkle or deform due to the volatilization of solvents and monomers, and the volatilization poses health and safety problems.Also, because it is liquid, workability is poor. There was a problem.

On the other hand, sheet-like adhesives, thermosetting types, moisture-curing types, hot-melt adhesives, etc., are available as adhesives that do not volatilize solvents or monomers and have good workability. It is now used for adhesion to the main body.

However, the sheet-like adhesive described above does not provide sufficient adhesive strength, and the plastic film may peel off due to vibration. On the other hand, all of the above sheet adhesives are capable of strong adhesion, but in the case of thermosetting or hot melt sheet adhesives, the thin plastic film shrinks due to heating at high temperatures. There is a problem that thermal deformation easily occurs. In addition, in the case of moisture-curable sheet adhesives, the curing speed is slow, so there is a problem that it takes time to obtain sufficient adhesive strength, resulting in poor production efficiency.

Generally, when manufacturing electrical components using thin plastic films as assembly parts, there are problems similar to those described above when adhering this film, such as wrinkles and other deformations in the bonded part of the film, and the adhesion of this film If it is insufficient, electrical characteristics, acoustic characteristics, etc. will be adversely affected.

[Problem that the invention seeks to solve]

This invention solves the problem of adhesion between a plastic film and an electrical component in the production of electrical components as described above, and uses a photocurable sheet-like adhesive different from the conventional one to bond the adhesive part of the film. The object of the present invention is to provide a method for manufacturing electrical components that can be quickly and firmly bonded without causing deformation such as wrinkles.

[Means for solving problems]

As a result of intensive studies to achieve the above object, the inventors found that by using a specific photocurable sheet-like adhesive to bond electrical components and plastic films, the adhesive area of the film could be easily wrinkled. The present inventors have discovered that it is possible to bond quickly and firmly without causing any deformation, leading to the creation of this invention.

That is, in bonding a light-transmissive film to an electrical component main body, the present invention first attaches the above film to the above main body via a photocurable sheet-like adhesive, and then irradiates it with light to bond the above adhesive. In the method for producing an electrical component to be cured, the photocurable sheet-like adhesive has a photopolymerizable unsaturated group covalently introduced into the outer layer of emulsion particles having a two-layer structure obtained by a two-step emulsion polymerization method. A photocurable sheet formed by molding a water-dispersible photocurable adhesive composition into a tape or sheet shape, which is made by incorporating a photosensitizer into an acrylic photocrosslinkable polymer emulsion capable of forming a film. The present invention relates to a method for manufacturing an electrical component, characterized in that the adhesive is a shaped adhesive.

[Structure and operation of the invention]

The acrylic photocrosslinkable polymer emulsion having a film-forming ability in which a photopolymerizable unsaturated group is covalently introduced into the outer layer of the two-layered emulsion particles used in this invention is the following acrylic copolymer. Examples include those obtained by adding functional unsaturated monomer (II) to union (1).

The above-mentioned acrylic copolymer (1) includes one or more unsaturated monomers as component a below, and internal crosslinking of a functional group-containing monomer as component below or component C as necessary. A two-stage emulsion in which a first stage emulsion polymerization is carried out using a polyfunctional monomer as an agent in the presence of an emulsifier and a polymerization initiator, followed by a second stage emulsion polymerization to be described later. It is obtained by a polymerization method.

The unsaturated monomers of component a used in the first stage emulsion polymerization include (meth)acrylic acid alkyl esters in which the alkyl group has 1 to 12 carbon atoms, benzyl (meth)acrylic acid, and cyclohexyl , esters such as tetrahydrofurfuryl, vinyl acetate, vinyl propionate, (meth)acrylonitrile, diacetone acrylamide, styrene, and the like.

In addition, as the functional group-containing monomer of component b used in the first stage emulsion polymerization as necessary, carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, fumaric acid, and itaconic acid are used. body, or hydroxyethyl (
meth)acrylate, hydroxypropyl(meth)acrylate, allyl alcohol, monoester of polyethylene glycol and (meth)acrylic acid, pentaerythritol tri(meth)acrylate, trimethyloldi(meth)acrylate, ethylene glycol or polyethylene glycol monoester Examples include hydroxyl group-containing monomers such as vinyl ether, propylene glycol, or monovinyl ether of polypropylene glycol.

Furthermore, the polyfunctional monomer as an internal crosslinking agent of component C is
A polyfunctional monomer having two or more acryloyl or methacryloyl groups as polymerizable carbon-carbon double bonds in the molecule, such as 1,4-butylene glycol di(meth)acrylate, 1,6- Hexane glycol di(meth)acrylate, neobentyl glycol di(meth)acrylate, polyprolene glycol di(meth)acrylate,
Examples include meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethanetetra(meth)acrylate.

In addition, as the emulsifier, any of the various emulsifiers used in normal emulsion polymerization can be used, and specific examples thereof include fatty acid salts, higher alcohol sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, and dialkyl sulfosuccinates. Examples include anionic surfactants such as acid salts, alkyl phosphate salts, and polyoxyethylene sulfate salts, and nonionic surfactants such as fatty acid esters of polyethylene oxide and long-chain alkyl monoethers.

Polymerization initiators include persulfates such as ammonium persulfate and potassium persulfate, peroxides such as hydrogen peroxide and benzoyl peroxide, or reducing agents such as persulfates and alkali metal sulfites and bisulfites. and azo compounds such as azobisvaleric acid and azobis(2-amidinopropane) hydrochloride.

In the second stage emulsion polymerization, a relatively soft unsaturated monomer having one acryloyl group or methacryloyl group in one molecule of the component a (a) is added to the first stage emulsion polymerization product. For example, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,
>50 to 95% by weight of vinyl acetate, etc., functional group-containing monomers of the above-mentioned components, d) epoxy group-containing monomers, such as glycidyl (meth)acrylate, and e) N-methylol (meth)acrylamide, N- One or more functional group-containing monomers selected from N-methylol group-containing monomers such as n-butoxy(meth)acrylamide 50-5
A mixture of an unsaturated monomer consisting of Add it in the same state. As a result, the emulsion particles generated in the first stage of emulsion polymerization are used as cores, and a second layer is formed outside the emulsion particles.
An acrylic copolymer (I) consisting of emulsion particles having an inner and outer two-layer structure in which a polymerization product layer is formed by emulsion polymerization in the second stage is obtained.

In addition, the amount ratio (weight ratio) of the unsaturated monomer used in the above-mentioned two-step emulsion polymerization method as component a
The ratio of the first stage to the second stage is preferably in the range of 97:3 to 20:80, preferably 90:10 to 40:60.

The functional unsaturated monomer (■) to be added to the acrylic copolymer (1) obtained as described above has a functional group that can react with the functional group of the copolymer (I). Acrylic monomers are used, examples of which include the above-mentioned, d
, functional group-containing C component, and #mer.

This addition reaction of the functional unsaturated monomer (n) is carried out by blowing air into the cooled aqueous dispersion of the acrylic copolymer obtained by the two-step emulsion polymerization, and then adding the monomer (n). If desired, amines such as triethylamine, tributylamine, and dimethylaniline are added as a catalyst to (2), and the mixture is heated to about 70° C. and stirred for about 2 to 24 hours. Through this addition reaction, a photopolymerizable unsaturated group is effectively covalently introduced into the outer layer of the two-layered emulsion particles, and an acrylic photocrosslinkable polymer emulsion having film-forming ability is obtained.

The amount of the functional unsaturated monomer (n) added is usually 1 to 40 parts by weight, preferably 5 parts by weight, based on 100 parts by weight of the acrylic copolymer obtained by two-step emulsion polymerization.
The amount of the amine as the catalyst is preferably 0.5 to 20 parts by weight based on the functional unsaturated sit form (II).
It is preferable to use it in an amount of about 5% by weight.

The photosensitizer used in the water-dispersible photocurable pressure-sensitive adhesive composition of the present invention is not particularly limited as long as it accelerates the photopolymerization reaction of the photocrosslinkable polymer, such as dimethylbenzyl chloride. , benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, hengeins such as α-methylhenzoin, anthraquinones such as l-chloroanthraquinone and 2-chloroanthraquinone, hensifhenone,
Examples include hesiphenones such as p-chlorobenzophenone and p-dimethylaminobenzophenone, and sulfur-containing compounds such as diphenyl disulfide and tetramethylthiuram disulfide. The amount of this photosensitizer is 0.05 to 2 parts by weight per 100 parts by weight of the photocrosslinkable polymer.
It is added in an amount of 0 parts by weight, preferably 0.5 to 10 parts by weight.

The method for adding this photosensitizer is to dissolve it using a small amount of a solvent or liquid unsaturated monomer of component a and add it to the acrylic photocrosslinkable polymer emulsion. It is preferable to absorb and impregnate the emulsion particles by stirring.

The water-dispersible photocurable pressure-sensitive adhesive composition obtained as described above may contain appropriate amounts of other compounding agents, if necessary. This method of addition is similar to the method of adding the photosensitizer described above.

Examples of the above-mentioned compounding agents include 1,4-ethylene glycol di(meth)acrylate 1. which is intended to increase the photocuring speed of the sheet-like adhesive and improve the strength after photocuring. 1,6-hexane gelicoldi(meth)acrylate, neopentyl glycol di(meth)
Monomers such as acrylate, polyethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethanetetra(meth)acrylate, or epoxy acrylate, urethane-modified acrylate, oligoester Examples include photopolymerizable unsaturated compounds such as oligomers such as acrylates, and two or more of these may be used in combination as necessary.

In addition, polymerization inhibitors that prevent thermal polymerization during production and reactions during storage, such as hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, p-benzoquinone, 2.5 lert-butylhydroquinone, phenothiazine, etc., coloring or decoration, etc. For example, pigments such as zinc white, yellow lead, and hengara, dyes such as toluidine red, fucrocyanine blue, and phthalosoanine green, other metal powders, glass beads, glass powder, glass flakes, etc., and on the adherend surface. For example, adhesion-imparting resins such as xylene resin and coumaron resin are used for the purpose of improving adhesive strength, and for example, triepoxypropyl isocyanurate, butoxymethylated melamine, etc. are used for the purpose of improving the &E concentration before light irradiation. crosslinking agents, etc.

In order to obtain a photocurable sheet-like adhesive from such a water-dispersible photocurable adhesive composition, this composition is poured onto a release sheet such as resin-treated paper or plastic film that has a low adhesive function. Just spread it out and then dry it. The thickness of this photocurable sheet adhesive is usually 10 to 200 μm.
It is better to set it to m.

In addition, this photocurable sheet-like adhesive can be used as a base material to provide functions such as reinforcing or supporting nonwoven fabrics such as rayon nonwoven fabrics and nylon nonwoven fabrics, and cloths such as cheesecloth. In order to embed such a base material, which can also be embedded, the above-mentioned composition may be applied or impregnated on both sides of the base material.

In the method of this invention, the light-transmitting film is adhered to the electrical component body using the thus obtained photocurable sheet-like adhesive. For this adhesion, the above-mentioned film is attached to the electrical component main body via the above-mentioned adhesive, and then the adhesive is photocured by irradiation with light.

The above-mentioned light transmitting film usually has a molecular weight of 200 to 1. IQQ
It is a plastic film that can pass light with a wavelength of nm, and its thickness is usually 10 to 500 μm, preferably about 10 to 100 μm. Examples of the material include polyester, polyimide, polyamide, fluororesin, polypropylene, and polyethylene.

The material of the adhesive part of the electrical component body to which this light-transparent film is bonded is usually aluminum, copper, enamel, insulating paper,
Such as polyester film.

The above light irradiation was performed using a high-pressure mercury lamp from the light-transmitting film side.
Using a light source such as an ultra-high pressure mercury lamp, metal halide lamp, carbon arc lamp, or xenon lamp, the
This is carried out by irradiating light with a wavelength of 0 nm for 0.3 seconds or more, preferably for 3 seconds or more. By this light irradiation, the above-mentioned photocurable sheet-like adhesive is photocured, and the light-transmissive film and the electrical component body are firmly adhered to each other. Further, at this time, deformation such as wrinkles does not occur in the bonded portion of the film.

Note that the above-mentioned adhesion of the light-transmissive film and the electrical component main body includes not only cases where the film is partially adhered but also cases where the entire surface is adhered.

Specific examples of electrical components manufactured by the method of the present invention include speakers using a plastic film made of polyester, polyimide, polyamide, fluorine resin, etc. as a diaphragm, or two-layer speakers using a polyester film as an insulating layer. coils and transformers,
Also included are intermediate frequency transformers and small transformers that use polyethylene film, polyester film, etc. to secure the ends of coils.

(Effect of the invention) The photocurable sheet-like adhesive used in the production method of the present invention is an acrylic adhesive in which a photopolymerizable unsaturated group is introduced into the outer layer of two-layered emulsion particles obtained by a two-step emulsion polymerization method. Because it is formed using a photocrosslinkable polymer emulsion as its main ingredient, the volumetric shrinkage of this sheet-like adhesive during photocuring is extremely small, and even when a thin plastic film is used as an assembly component, the film does not shrink during curing. It does not cause deformation such as wrinkles in the bonded part.Moreover, strong adhesion is possible, and together with the absence of the above deformation, it is possible to obtain an electrical component with good electrical properties and acoustic properties. In addition, since it is photocured, the curing speed is fast, and electrical parts can be manufactured with good production efficiency.

[Examples] Examples of the present invention will be described below. Note that in the following, parts refer to parts by TL amount.

Example 1 Ethyl methacrylate 65 parts Sodium dodecyl sulfate 1 part Ion exchange water
500mff of 100 parts of the above blended composition
After heating and stirring for 1 hour at 70° C. under an inert gas, 0.05 part of ammonium persulfate was added and the mixture was reacted at 70° C. for 3 hours to perform the first stage emulsion polymerization. Next, 22 parts of butyl acrylate, 8 parts of methacrylic acid, 1 part of sodium dodecyl sulfate, and 1 part of ion-exchanged water.
53 parts Ammonium persulfate 0.05
70% of the emulsified composition was added to the polymerization product obtained in the first stage emulsion polymerization.
It was added dropwise over 2 hours while heating and stirring at °C, and was further reacted at this temperature for 1 hour to perform the second stage of emulsion polymerization, resulting in an aqueous dispersion of an acrylic copolymer consisting of two-layered emulsion particles. I got it.

Subsequently, the above water dispersion was cooled to 25°C, air was blown into the liquid for 1 hour, and then 8 parts of glycidyl methacrylate and 0.1 part of dimethylaniline were added, and the reaction was carried out at 70°C for 3 hours. , an acrylic photocrosslinkable polymer emulsion was obtained.

A solution of 1 part of hengeine ethyl ether in 5 parts of trimethylolpropane triacrylate was gradually added dropwise to this emulsion while rapidly stirring the emulsion, and mixed uniformly to form a water-dispersible photocurable adhesive composition. Obtained. This composition was dried on silicone-treated paper to a thickness of 5.
It was coated to a thickness of 0 μm and dried at 100° C. for 5 minutes to obtain a photocurable sheet-like adhesive.

Using this photocurable sheet-like adhesive, a diaphragm made of a polyester film having a thickness of 16 μm was adhered to a speaker body in the following manner to manufacture a speaker.

That is, after pasting the above-mentioned diaphragm onto the speaker body via the above-mentioned adhesive, the diaphragm side was irradiated with light for about 3 seconds from a distance of 10cm using a high-pressure mercury lamp (80W/am/lamp). The above adhesive was cured.

Finally, in order to securely fix the diaphragm mentioned above,
As shown in FIGS. 1 to 3, a ring 4 made of polyester with a thickness of 150 μm is attached to the adhesive part of the diaphragm 3 that is adhered to the speaker body 1 via a photocurable sheet adhesive 2. Paste via the photocurable sheet-like adhesive 5 described below,
The adhesive 5 was then cured by irradiation with light in the same manner as above.

FIG. 2 is a plan view of the ring 4 used at this time, and FIG. 3 is an enlarged view of the part (■) in FIG. 1.

In the speaker obtained in this way, no deformation such as wrinkles occurred at the bonded portion of the diaphragm, and as is clear from the test examples below, the diaphragm was firmly bonded. As a result, this speaker had good acoustic characteristics.

Example 2 2-Ethylhexyl acrylate 40 parts Sodium dodecylbenzenesulfonate 3 parts Ion-exchanged water 154.5 parts The above blended composition was placed in a 50 Qmff flask and heated under inert gas for 70 minutes.
After heating and stirring at .degree. C. for 1 hour, 0.05 part of ammonium persulfate was added and the mixture was reacted at 70.degree. C. for 3 hours to perform the first stage of emulsion polymerization. Subsequently, 0.05 part of ammonium persulfate was added to this polymerization product, and a mixture consisting of 15 parts of vinyl acetate and 6 parts of glycidyl methacrylate was heated and stirred into the polymerization product at 70°C. The mixture was added dropwise over a period of 2 hours, and the mixture was further reacted at this temperature for 1 hour to perform a second stage of emulsion polymerization, thereby obtaining an aqueous dispersion of an acrylic copolymer consisting of two-layered emulsion particles.

Subsequently, the above aqueous dispersion was cooled to 25°C, air was blown into the liquid for 1 hour, and then 3 parts of acrylic acid and 0.1 part of dimethylaniline were added, and the reaction was carried out at 70°C for 3 hours. A photocrosslinkable polymer emulsion was obtained.

To this emulsion was added 1 part of benzophenone dissolved in 5 parts of pentaerythritol, and
The mixture was stirred for a period of time and mixed uniformly to obtain a water-dispersible photocurable pressure-sensitive adhesive composition. This composition was placed on a rayon nonwoven fabric with a thickness of 50 μm on silicone-treated paper, and the thickness after drying was 1.
It was coated and impregnated to a thickness of 30 μm, and dried at 100° C. for 5 minutes to obtain a photocurable sheet-like adhesive.

A speaker was manufactured in the same manner as in Example 1 using this photocurable sheet-like adhesive. In this speaker, there are no wrinkles or other deformations in the bonded part of the diaphragm to the speaker body, and as is clear from the test examples below, the diaphragm is strongly bonded, so this speaker has excellent acoustic performance. The characteristics were good.

Example 3 40 parts of methyl methacrylate 160 parts of ion-exchanged water 50 parts of the above blended composition
Pour into a 0m6 flask and heat at 70°C under inert gas.
After heating and stirring for an hour, 0.05 part of ammonium persulfate was added and the mixture was reacted at 70°C for 3 hours to carry out the first stage of emulsion polymerization. Next, an emulsified composition consisting of 40 parts of butylene acrylate and 0.05 parts of ammonium persulfate was heated at 70°C into the polymerization product obtained in the first stage emulsion polymerization. The mixture was added dropwise over 2 hours with stirring, and the mixture was further reacted at this temperature for 1 hour to perform a second stage of emulsion polymerization, thereby obtaining an aqueous dispersion of an acrylic copolymer consisting of two-layered emulsion particles.

Subsequently, the aqueous dispersion was cooled to 25°C, air was blown into the liquid for 1 hour, and then 5 parts of glycidyl methacrylate and 0.1 part of dimethylaniline were added, and the reaction was carried out at 70°C for 3 hours. A photocrosslinkable polymer emulsion was obtained.

A solution of 1 part of dimethylbenzyl ketal dissolved in 5 parts of 1,6-hexane glycol diacrylate was gradually added dropwise to this emulsion while rapidly stirring the emulsion, and mixed uniformly to form a water-dispersible photocurable adhesive. I got something. A photocurable sheet-like adhesive was obtained using this composition in the same manner as in Example 2.

A speaker was manufactured in the same manner as in Example 1 using this photocurable sheet-like adhesive. In this speaker, there are no wrinkles or other deformations at the bonded part of the diaphragm to the speaker body (Also, as is clear from the test examples below, this diaphragm is strongly bonded, so this speaker had good sound characteristics.

Test Examples The adhesive properties of the photocurable sheet-like adhesives obtained in Examples 1 to 3 were investigated as follows, and the results are shown in the table below.

180 degree peeling adhesive strength> A 60 μm thick button 11 on one side of the photocurable sheet adhesive.
After attaching a vinyl chloride sheet, cut it into 20 pieces to make an adhesive tape, attach this tape to a 100 μm thick polyester film, leave it for 30 minutes, peel it off 180 degrees, and check the adhesive strength at 20°C and 65°C. %RH and a peeling speed of 300 mm/min.

In addition, after pasting the above tape on the above polyester film, a high-pressure mercury lamp (80 W/cm/1 lamp) was applied.
The above adhesive was cured by irradiating light for about 5 seconds from a distance of 0 value, and then left at 20° C. for 24 hours, and then peeled off at 180 degrees in the same manner as above to measure the adhesive strength.

<Tack> Roll a stainless steel ball onto the surface of a photocurable sheet-like adhesive from a run-up distance of IQ cm on a slope with an inclination angle of 30 degrees, and measure the ball corner ( Diameter = ball Nuxl/36 inches)
It was shown in Note that the measurement was carried out under conditions of 2 parts C and 65% RH.

<Tensile shear adhesive strength> Photocurable sheet adhesive 20 +n+ X 'I Q
Cut it into the size of the fin, paste a 100 μm thick polyester film on both sides, and heat it with a high pressure mercury lamp (80 W/cm).
/ 1' light) from a distance of 1Qcm for about 5 hours, then left at 20℃ for 24 hours, then heated to 20℃1
Tensile shear adhesive strength was measured under conditions of 65% RH and a pulling rate of 50 min/min.

[Brief Description of the Drawings] Fig. 1 is a sectional view showing an example of an electrical component obtained by the method of the present invention, Fig. 2 is a plan view of a ring used in manufacturing the above-mentioned electrical part, and Fig. 3 is a sectional view showing an example of an electrical component obtained by the method of the present invention. This is an enlarged view of the ■ part in Figure 1. l...Speaker body (electrical parts body), 2.5...
・Photocurable sheet-like adhesive, 3... Vibration plate (light-transparent film) Patent applicant Nitto Electric Industry Co., Ltd. No. 1 Figure 3,

Claims (1)

[Claims] (1) When joining a light-transmissive film to the main body of an electrical component, the above film is attached to the above main body via a photocurable sheet-like adhesive, and then the above film is irradiated with light to harden the above adhesive. In the method for producing parts, the photocurable sheet-like adhesive has a film-forming ability by covalently introducing photopolymerizable unsaturated groups into the outer layer of emulsion particles having a two-layer structure obtained by a two-step emulsion polymerization method. It is a photocurable sheet-like adhesive formed by forming a water-dispersible photocurable adhesive composition, which is an acrylic photocrosslinkable polymer emulsion containing a photosensitizer, into a tape or sheet shape. A method of manufacturing an electrical component characterized by: