JPH11158437A - Bonding process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bond a base sheet to an adherend in spots or partially at good positional accuracy by jetting a pressure-sensitive material having a cationically polymerizable compound and a cationic photopolymerization initiator from the head of an ink jet printer to apply it to specified regions of a base sheet and polymerizing it by irradiation with light before or after sticking the sheet to an adherend. SOLUTION: A pressure-sensitive material is used which has desirably an adjusted viscosity of 100-1,000 cP and is prepared by mixing a pressure-sensitive adhesive polymer (e.g. n-butyl acrylate/ethyl acrylate copolymer) with a cationically polymerizable compound, desirably being an epoxy-containing compound (e.g. bisphenol A epoxy resin) and a cationic photopolymerization initiator (e.g. aromatic sulfonium antimonate initiator). This can solve the problem that plugging occurs when the pressure-sensitive adhesive material is dried at the exit of the head of an ink jet printer and can permit the easy and efficient production of a pressure-sensitive adhesive sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of bonding a substrate sheet and an adherend in a dot-like or partial manner.

[0002]

2. Description of the Related Art A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed only in a predetermined area is used for various purposes. For example, I
When attaching the C card module to the PVC sheet,
An adhesive layer is provided only on a predetermined area of the PVC sheet, and an IC card module is attached to the adhesive layer. Also,
Also in a flexible printed circuit board (FPC), an adhesive sheet having such an adhesive layer in part may be used.

Conventionally, a pressure-sensitive adhesive sheet having such a pressure-sensitive adhesive layer has been produced by punching a double-sided tape into a predetermined shape and bonding it to a base material of the pressure-sensitive adhesive sheet. In such a manufacturing method, processes such as punching of the double-sided tape and bonding of the punched double-sided tape are required, and there is a problem that the manufacturing process is complicated.

As a method of solving such a problem, a method of applying a pressure-sensitive adhesive only in a predetermined area in advance using a mesh screen such as a gravure plate or polyester is conceivable. However, the application of the pressure-sensitive adhesive by such printing requires the preparation of a pressure-sensitive adhesive having characteristics suitable for printing, and further has a problem that the pressure-sensitive adhesive is dried and a film is easily peeled off. Therefore, it was necessary to produce a large amount of pressure-sensitive adhesive sheets at one time. Further, as a method of printing the adhesive, a method of ejecting the adhesive from a head of an ink jet printer and applying the adhesive to a predetermined area is conceivable.

[0005]

However, such a method has a problem that the adhesive dries at the outlet of the head of the ink jet printer and the head is clogged.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional problem and to easily and efficiently form a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in a predetermined region without causing clogging of a head of an ink jet printer. An object of the present invention is to provide a manufacturing method that can be manufactured.

[0007]

The process for producing a pressure-sensitive adhesive sheet according to the present invention is a method for adhering a substrate sheet and an adherend in a dot-like or partial manner, comprising a cationically polymerizable compound and a cationic photopolymerization initiator. The adhesive material containing is sprayed from the head of the inkjet printer, applied to a predetermined area on the base sheet, and before or after laminating the adherend, the adhesive material is irradiated with light. This is a bonding method characterized in that polymerization is performed.

In the present invention, the adhesive material jetted from the head of the ink jet printer comprises a cationic polymerizable compound and a photo cationic polymerization initiator,
It is also prepared by blending other additives as necessary.

As the adhesive polymer, those generally used as a main component of the adhesive can be used, and examples thereof include rubber-based, acrylic-based, and silicone-based adhesives.

The rubber-based pressure-sensitive adhesive is prepared by blending a polymer of natural rubber or synthetic rubber with a tackifier, a plasticizer and the like. Synthetic rubbers include polyisobutylene, acrylic rubber, acrylonitrile / butadiene rubber (NBR), random styrene / butadiene rubber, butyl rubber, isoprene rubber (IR), butadiene rubber (BR), ethylene / propylene rubber (EPM), ethylene / Propylene / diene rubber (EPDM), urethane rubber, styrene /
Isoprene / styrene block rubber (SIS), styrene / ethylene / butylene / styrene block rubber (SE
BS), styrene / butadiene block rubber, and the like.

The acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive mainly containing a (co) polymer mainly containing an alkyl (meth) acrylate. Examples of the alkyl group include methyl, ethyl,
Examples include n-butyl, i-butyl, hexyl, octyl, i-octyl, 2-ethylhexyl, nonyl and the like.
In the case of a copolymer, acid components such as (meth) acrylic acid and maleic acid, acrylonitrile, urethane acrylate, styrene, vinyl acetate, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate,
Copolymers obtained by copolymerizing ε- (poly) caprolactone acrylate, tetrahydrofuranyl acrylate, and the like can be given.

The silicone adhesive is generally a mixture of a silicone rubber such as polydimethylsiloxane or polydiphenylsiloxane and a silicone resin such as polysiloxane having a trimethylsilyl group or a triphenylsilyl group.

These adhesives have a glass transition temperature (T
g) is preferably 20 ° C. or lower. If the Tg is high, the pressure sensitivity is reduced and the room temperature tackiness is reduced, and poor adhesion such as peeling may occur at low temperatures.

In the present invention, the cationically polymerizable compound contained in the adhesive material includes a photocationically polymerizable functional group such as a hydroxyl group, a vinyl ether group, an episulfide group, an ethyleneimine group and / or an epoxy group in the molecule. Various monomers, oligomers or polymers having the same can be used. Further, the polymer having these functional groups is not limited, and various polymers such as acrylic, urethane, polyester, polyolefin, polyether, natural rubber, block copolymer rubber, and silicone can be used. it can. Further, the composition of the pressure-sensitive adhesive may have these cationically polymerizable functional groups. For example, in the case of a rubber-based pressure-sensitive adhesive, an epoxidized SBS, and in the case of an acrylic-based pressure-sensitive adhesive, a glycidyl methacrylate copolymer or the like can be mentioned as a pressure-sensitive adhesive having a cationically polymerizable functional group. When a cationically polymerizable functional group is introduced into the pressure-sensitive adhesive, it is preferable that the pressure-sensitive adhesive property be in a range not to impair the pressure-sensitive adhesive properties.

As the photocationically polymerizable compound, a compound having an epoxy group is preferably used. Since ring-opening polymerization of an epoxy group has high reactivity and a short curing time, it does not require a long time to polymerize and form an adhesive.

As the compound having an epoxy group,
Epoxy resins are preferably used. Examples of the epoxy resin include bisphenol A type, bisphenol F type, phenol novolak type, cresol novolak type, glycidyl ether type, and glycidylamine type epoxy resins.

Further, epoxy group-containing oligomers can also be suitably used. For example, bisphenol A type epoxy oligomers (for example, trade names "Epicoat 1001" and "Epicoat 1002" manufactured by Yuka Shell Epoxy Co., Ltd.)
Etc.).

Further, an addition polymer of the above-mentioned epoxy group-containing monomer or oligomer may be used. For example, glycidylated polyester, glycidylated polyurethane, glycidylated acryl and the like can be mentioned.

The cationic photopolymerizable compound may be modified with a different resin or a functional group as required. Further, those having a reactive functional group such as those having a radical polymerizable unsaturated bond introduced therein may be used.

The cationically polymerizable functional group equivalent contained in the adhesive material of the present invention is preferably 5000 g-r
esin / mol or less. If this equivalent is large, the functional group concentration in the composition may be reduced, resulting in insufficient cationic polymerization and reduced adhesiveness. Therefore, it is preferable that the composition is determined such that the equivalent of the cationically polymerizable functional group falls within such a range.

In the present invention, the cationic photopolymerization initiator contained in the adhesive material may be either an ionic photoacid generating type or a nonionic photoacid generating type. Examples of the ionic photoacid generating type include onium salts of aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts, and organic metal complexes such as iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes. be able to. More specifically, for example, Optomer SP-150 (made by Asahi Denka Co., Ltd.), Optomer SP-17
0 (manufactured by Asahi Denka), UVE-1014 (manufactured by General Electronics), CD-1012 (manufactured by Sartomer)
Commercially available compounds such as can be used. As the nonionic photoacid generating type, nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenolsulfonic acid ester, diazonaphthoquinone, N-hydroxyimidosulfonate and the like can be used. The cationic photopolymerization initiator may be used alone or in combination of two or more.

The content of the cationic photopolymerization initiator is 0.0001 for the cation to 1 mol of the cationically polymerizable functional group.
It is preferable to mix them so as to generate mol% or more. If the content is less than this, the cationic photopolymerization does not proceed sufficiently, and the curing rate tends to be slow.

In the present invention, the adhesive material prepared as described above is sprayed from a head of an ink jet printer and applied to a predetermined region on a base sheet. The head of the inkjet printer used in the present invention is not particularly limited, and a general inkjet printer head can be used. Normally, the head of an ink jet printer has a structure in which a liquid is ejected by pressure generated by using vibration caused by piezo. Therefore, it is preferable that the adhesive material accommodated in the solution cartridge or the tank of the ink jet printer and ejected from the head is adjusted to a viscosity of 100 to 1000 cps.

In the present invention, the adhesive material applied to a predetermined area on the base sheet is irradiated with light to be photopolymerized. As the irradiation light, microwave, infrared light, visible light, ultraviolet light, X-ray, γ-ray, etc. can be used.
Generally, ultraviolet light is preferably used because it is easy and convenient to handle and can obtain relatively high energy. More preferably, ultraviolet light having a wavelength of 200 to 400 nm is used.

In the present invention, the photocationically polymerizable compound in the adhesive material is polymerized by irradiation with light, so that a polymer suitable as an adhesive is obtained. The number-average molecular weight of the tacky material after photopolymerization is 50,000 in order to make tack, tackiness and cohesion (force corresponding to prevention of displacement from the base material sheet to be adhered) sufficient. It is preferably between 1 and 1,000,000. When an adhesive material having such a molecular weight is to be ejected from the head of an ink jet printer, clogging occurs at a discharge portion of the head, resulting in defective ejection. In the present invention,
The adhesive material before polymerization is ejected from the head of an ink jet printer, and the adhesive material after application is polymerized to give desired properties as an adhesive. Therefore, it is possible to form a pressure-sensitive adhesive layer having desired characteristics without causing such clogging in the head portion.

In the present invention, the cross-linking rate of the pressure-sensitive adhesive after polymerization is 30% as a gel fraction insoluble in a solvent (ethyl acetate).
It is preferable that the content be from 90% by weight to 90% by weight. 30% by weight
If it is less than 3, the cohesive force may be insufficient and a shift may occur. On the other hand, if it exceeds 90% by weight, tackiness may decrease and adhesiveness may decrease.

In the present invention, it is preferable to adjust the irradiation energy at the time of light irradiation so that the above gel fraction is obtained. Further, in the present invention, by heating after light irradiation, the curing speed can be improved, and polymerization can be performed in a short time. As a heating method, a general oven can be used. In addition to heating by heat conduction, non-contact heating such as infrared rays, electromagnetic waves, and induction heating can be used as appropriate. Heating can also be performed using heat generated from a light source for light irradiation. In this case, by shortening the distance from the light source or increasing the irradiation intensity,
The heat from the light source can be used effectively.

The pressure-sensitive adhesive sheet of the present invention is manufactured by spraying and applying a pressure-sensitive adhesive material to a predetermined area on a base sheet. Various sheets can be used as the base sheet according to the characteristics required for the pressure-sensitive adhesive sheet. In particular, polyester, polyolefin, nylon, plastic films such as PVC, paper, nonwoven fabric, metal foil, etc.
It can be suitably used as a base sheet.

The adhesive sheet produced in the present invention is laminated with a separator (paper or plastic film coated with silicone, long-chain alkyl release agent, etc.) to protect the adhesive surface. Or another adherend may be attached.

According to the present invention, an adhesive layer can be formed by spraying an adhesive material directly from a head of an ink jet printer onto an arbitrary predetermined area of a substrate sheet.
Therefore, the pressure-sensitive adhesive layer can be formed in an arbitrary region on the base sheet with good positional accuracy. Therefore, the manufacturing process can be significantly simplified as compared with the conventional manufacturing process of an adhesive sheet manufactured by punching a double-sided tape. In addition, it is possible to form a pressure-sensitive adhesive layer having a complicated shape by linking with a computer. Further, according to the production method of the present invention, a small lot of pressure-sensitive adhesive sheets can be produced.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION A pressure-sensitive adhesive, a cationically polymerizable compound and a photo-cationic polymerization initiator are blended in the following blending ratio,
A sticky material was obtained.

・ Adhesive n-butyl acrylate / ethyl acrylate copolymer (50/50) (molecular weight 700,000) 40 parts by weight ・ Cationically polymerizable compound Bisphenol A type epoxy resin “Epicoat # 828” (oiling shell) 20 parts by weight Glycidyl ether type epoxy resin "Epicoat # 190" (manufactured by Yuka Shell Epoxy) 40 parts by weight Photocationic polymerization initiator Aromatic sulfonium antimonate-based polymerization initiator "ADEKA OPTOMER SP170" (Asahi Denka Co., Ltd.) 1 part by weight The viscosity of the obtained adhesive material was 800 cps.

The obtained adhesive material was applied to a square donut-shaped part having a shallow counterbore of a PVC sheet (thickness: 0.7 mm) using an ink jet printer head (manufactured by Epson, PM-700C). It was applied by spraying so that the final thickness became 50 μm. The adhesive material after application was irradiated with light by an ultra-high pressure mercury lamp at 0.4 J / cm ² to initiate polymerization. On the obtained adhesive layer,
A PET separator subjected to silicone release treatment was laminated to obtain an adhesive sheet. The final curing rate of the pressure-sensitive adhesive layer in this pressure-sensitive adhesive sheet was 6% by gel fraction insoluble in ethyl acetate.
It was 0% by weight.

An IC module was attached to the pressure-sensitive adhesive layer portion of the pressure-sensitive adhesive sheet obtained as described above, and a bending test was performed. The bending test was performed 1000 times, and the lift of the IC module was within 0.2 mm.
The bending test was performed according to JIS-X-6303 Reference 2
The test was performed in accordance with the test method for bending characteristics.

In order to measure the adhesive strength of the adhesive material used in this example, a PET film (thickness: 50 μm) was used.
Then, a pressure-sensitive adhesive material was applied to the entire surface by using the head of an ink-jet printer in the same manner as in the above example, and then irradiated with light to produce a pressure-sensitive adhesive sheet. With respect to the produced pressure-sensitive adhesive sheet, a 180 ° SP peeling force was measured according to JIS-Z-1528. As a result, the peel force was 800 g / 10 m.
m, which was confirmed to have a sufficient adhesive strength.

[0036]

According to the present invention, a pressure-sensitive adhesive material can be ejected from the head of an ink jet printer to form a pressure-sensitive adhesive layer on any given area on a base sheet with good positional accuracy. . Therefore, it is possible to manufacture a pressure-sensitive adhesive sheet having a good positional accuracy of the pressure-sensitive adhesive layer in a simple manufacturing process as compared with a conventional process of manufacturing a pressure-sensitive adhesive sheet formed by punching a double-sided tape.

Further, according to the present invention, the adhesive material before polymerization is sprayed and applied from the head of the ink jet printer, and then polymerized after the application. A pressure-sensitive adhesive sheet can be manufactured efficiently and efficiently.

Claims (1)

[Claims] 1. A method for bonding a substrate sheet and an adherend in a dot-like or partial manner, wherein a sticky material containing a cationically polymerizable compound and a photo-cationic polymerization initiator is jetted from an ink jet printer head. Then, the adhesive method is applied to a predetermined area on the base sheet, and before or after laminating the adherend, the adhesive material is irradiated with light to be polymerized.