JP3372092B2 - Laminates and adhesive films - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate which can effectively recycle and recycle an article whose constituent members are assembled with an adhesive tape or the like. More specifically, the present invention relates to a laminate, an adhesive film, or a tape that can be easily disassembled in the bonded portion of the above-mentioned article and can contribute to reduction of industrial waste by collecting and reusing members constituting the article.

[0002]

2. Description of the Related Art When a metal or plastic nameplate is adhered to a plastic molded product to form a product, a double-sided adhesive tape is often used as an adhering means. The double-sided adhesive tape is required to have a strong adhesive strength so that the double-sided adhesive tape is firmly adhered and does not come off during the use of the product. By the way, in various fields, the issue of global environment protection such as effective use of resources, reuse of dismantled parts, reuse of products, reduction of industrial waste, etc. has become a problem, and in recent circumstances, the need for it is increasing. I'm doing it. Therefore, it is desired that the above-mentioned products are also reused once they have been used. At that time, however, the work of disassembling the bonded portion is difficult due to the strong adhesive properties of the adhesive.

Although the product is firmly adhered during the period of use, an adhesive or a double-sided adhesive tape is used so that the product is easily disassembled into its components when it is no longer used and is discarded. It is considered to apply various means. For example, there is a method in which part of the adhesive layer or the constituent layer of the tape is foamed by heating to lose the adhesive function, whereby the adhesive is easily broken and the product is disassembled into pieces. Alternatively, many methods have been reported in which the adhesive function is lost by irradiating ultraviolet rays to react the adhesive components. Also, paper with weak interlayer strength,
For example, there has been proposed a structure in which newspaper is used as a part of the adhesive layer to easily break the newspaper when the product is discarded.

However, the above-mentioned means requires a heating means when, for example, foaming by heating, and in consideration of reuse, it must be a material which does not deteriorate by heating. Larger products will require larger heating devices. In addition, depending on the product, the adhesive layer is required to be a very thin layer, and there is a product such as newsprint which cannot use other than the adhesive. Further, the product itself is required to be transparent, or the constituent members such as the base material and the support and the adhesive layer are required to be transparent or light transmissive so that ultraviolet rays can be transmitted. There is also.

Therefore, it is desired that the function of the adhesive can be lost without requiring a large-scale device, without requiring energy such as ultraviolet rays or infrared rays, or without being affected by moisture in the air, water, solar heat or the like. .

[0006]

The present inventors have made it possible to easily disassemble an article composed of an adhesive tape or the like and reuse it.
As a result of various studies on adhesive layers suitable for recycling, the most effective and useful laminate was found. That is, the present invention is one in which a plastic film is laminated on both sides of an adhesive layer containing a reactive monomer that can be cured by irradiation of ultraviolet rays and electron beams and a photoreaction initiator, and the adhesive layer between the plastic film layer and the adhesive layer is It relates to a laminate having a difference in adhesive strength and cohesive strength of the adhesive layer itself.
The above-mentioned required problems can be solved only by providing a difference between the adhesive strength between the plastic film layer and the adhesive layer and the cohesive strength of the adhesive layer itself.

FIG. 1 is a cross-sectional view showing a laminate 4 which is an embodiment of the present invention, in which 1 and 1'are plastic films, 2 is an adhesive layer, and 3 is an adhesive portion. FIG. 2 is a sectional view of an adhesive tape 6 according to another embodiment of the present invention,
1, 1'is a plastic film, 2 is an adhesive layer, 3 is an adhesive portion, and 5'is an adhesive layer.

As described above, the feature of the present invention resides in that the adhesive strength between the plastic films 1 and 1'and the adhesive layer 2 is different from the cohesive strength of the adhesive layer 2 itself. When the adhesive strength between the plastic films 1 and 1'and the adhesive layer 2 is larger than the cohesive strength of the adhesive layer 2 itself, the plastic films 1 and 1'laminated on both surfaces of the adhesive layer 2 are pulled. When peeled off, the adhesive layer 2 is destroyed as shown in FIG. That is, when a destructive force is applied to the adhesive portion 3, the adhesive layer 2 is destroyed and is destroyed between the plastic films, and the article in which the constituent members are assembled by the adhesive tape is disassembled into the constituent members. To be done.

On the other hand, when the adhesive strength between the plastic film 1, 1'and the adhesive layer 2 is smaller than the cohesive strength of the adhesive layer 2 itself, the plastic film 1 laminated on both sides of the adhesive layer 2 When 1'is peeled off, peeling occurs at the interface between the adhesive layer 2 and the plastic film 1 or 1 ', as shown in FIG. That is, when a destructive force is applied to the adhesive portion 3 of the adhesive tape, the adhesive layer 2 and the plastic film 1 or 1'are separated from each other. Disassembled into components

The adhesive layer of the laminate of the present invention contains ultraviolet rays,
A reactive monomer such as an acrylic monomer that causes a curing reaction or a crosslinking reaction when irradiated with an electron beam is used. Examples of the reactive monomer include an acrylic ester monomer having at least one reactive C = C bond at the molecular end, an acrylic ester derivative monomer, an epoxy acrylate monomer, and a urethane acrylate. Specifically, "Aronix" series manufactured by Toagosei Co., Ltd., special acrylate monomer series manufactured by Kyoeisha Yushi Co., Ltd., "KAYARAD" series manufactured by Nippon Kayaku Co., Ltd., manufactured by Osaka Organic Chemical Industry Co., Ltd. Commercial products such as "Viscoat" series, "New Frontier" series manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., and "Ripoxy (vinyl ester resin)" manufactured by Showa Highpolymer Co., Ltd. may be mentioned.

As the photoreaction initiator added to the adhesive layer, benzoyl alkyl ether, benzophenone / tertiary, benzyl methyl ketal, hydroxycyclohexyl phenyl ketone, 2,2-diethoxyacetophenone, α-hydroxyisobutylphenone, chloro. Thioxanthone can be used.

In the adhesive layer, in addition to the above-mentioned reactive monomer and photoreaction initiator, usual synthetic resin, polymer components such as rubber, etc. are added. As the polymer component, for example,
Various acrylic esters, acrylic acid, copolymers of vinyl acetate, natural rubber, styrene-butadiene rubber (SB
R), isoprene rubber (IR), butadiene rubber (B
R), nitrile rubber (NBR), chloroprene rubber (C
R), butyl rubber (IIR), styrene isoprene styrene block polymer (SIS) and styrene butadiene styrene block polymer (SBS).

Further, in order to adjust the adhesiveness between the plastic film and the adhesive layer, the cohesive force of the adhesive layer, etc., a tackifier (tackifier), filler such as calcium carbonate, talc, clay, etc., oil, liquid A softening agent such as a resin can also be added.

Examples of the plastic film include polyester film, polypropylene film, polyethylene film, polyvinyl chloride film, polyvinylidene chloride film, polyacrylic ester film, polyimide film, nylon film, polyvinyl alcohol film and vinylon film. Among them, polyester film, polypropylene film,
A polyethylene film, a polyvinyl chloride film, a polyvinylidene chloride film, and a polyacrylic ester film are preferable.

The above-mentioned respective components for forming the adhesive layer are
It can be formed by applying a solution such as water or an organic solvent to a plastic film by a roll coater, an extrusion die coater, or the like, or by further heating and drying. The above solution can be applied to one side of a plastic film, and another plastic film can be attached thereto to form the laminate of the present invention.

The adhesive layer thus formed contains a reactive monomer that undergoes a curing reaction and a crosslinking reaction upon irradiation with ultraviolet rays and electron beams, and a photoreaction initiator. By irradiating with an electron beam, the adhesive layer can be cured. When ultraviolet rays are used for curing, either one of the plastic films must be transparent or light-transmissive. When curing by electron beam irradiation, the amount of energy is large, so the transparency and light transparency of the film are not necessarily required.

In the laminate of the present invention, a second adhesive such as a pressure-sensitive adhesive, a so-called pressure-sensitive adhesive, a heat-sensitive adhesive, a heat-activatable adhesive, a so-called hot-melt adhesive, or a thermosetting adhesive is provided on one or both sides. By providing the agent layer, a usual single-sided adhesive tape, film, double-sided adhesive tape, or film can be obtained.

As described above, even when the adhesive layer is provided on one side or both sides of the plastic film, after the adhesive layer is provided, the adhesive layer is irradiated with ultraviolet rays or electron beams as described above. Can be cured. When a curing reaction is caused by irradiation with ultraviolet rays, the adhesive layer provided on one side or both sides of the plastic film needs to be transparent or light transmissive.

[0019]

【Example】

Example 1 100 parts by weight of "Paracron" BX-1500 (acrylic ester polymer, manufactured by Negami Kogyo Co., Ltd.) and "lipoxy" SP
-4010 [acrylic epoxy, Showa Highpolymer Co., Ltd.]
100 parts by weight and "Irgacure" as a photoreaction initiator
651 (benzyl methyl ketal, manufactured by Ciba Geigy)
4 parts by weight were mixed to obtain an adhesive. The obtained adhesive was applied on one side of a 25-micron-thick polyester film and dried to form an adhesive layer having a thickness of 30-micron. A 25-micron-thick polyester film was further bonded to this adhesive layer to form a laminate. The obtained laminate was irradiated with ultraviolet rays at 15 cm for 5 seconds using one high pressure mercury lamp (output 80 W / cm) to cure the adhesive layer. Acrylic pressure-sensitive adhesive layers were formed on both sides of this laminate so as to have a thickness of 50 μm, to prepare a double-sided adhesive tape.

Example 2 "Asaprene" T-420 [styrene-butadiene-styrene block polymer, manufactured by Asahi Chemical Industry Co., Ltd.] 100
Parts by weight and "JSR PB 805" [butadiene resin,
Made by Japan Synthetic Rubber Co., Ltd.] 50 parts by weight is dissolved in 100 parts by weight of toluene, and "New Frontier" IBA
[Isobornyl acrylate, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.]
80 parts by weight, 2 parts by weight of benzophenone, and 2 parts by weight of dimethylaminoethanol were mixed to prepare an adhesive, which was coated on one side of a polypropylene film having a thickness of 40 μm and dried to form an adhesive layer having a thickness of 20 μm. A polyester film having a thickness of 40 μm was further attached to this adhesive layer to form a laminate. The obtained laminate was irradiated with ultraviolet rays at 15 cm for 5 seconds using one high pressure mercury lamp (output 80 W / cm) to cure the adhesive layer. Further, a natural rubber-based pressure-sensitive adhesive layer was provided on both sides of this laminate to obtain a double-sided adhesive tape.

Example 3 Example 2 except that benzophenone and dimethylaminoethanol were omitted from the components of the adhesive used in Example 2.
A laminate was prepared in the same manner as above, and after providing a pressure-sensitive adhesive layer, the adhesive layer was cured by electron beam irradiation with a strength of 3 Mrad.

Example 4 To 100 parts by weight of "Paracron" NS-2500 (acrylic ester polymer, manufactured by Negami Kogyo Co., Ltd.), "lipoxy" SP was added.
-1060 [acrylic epoxy, Showa Highpolymer Co., Ltd.]
50 parts by weight and "Irgacure" as a photoreaction initiator
651 (benzyl methyl ketal, manufactured by Ciba Geigy)
4 parts by weight were mixed to obtain an adhesive. The obtained adhesive was applied to one side of a 25-micron-thick polyester film and dried to obtain a 30-micron-thick adhesive layer. A 25-micron-thick polyester film was further bonded to this adhesive layer to form a laminate. 15 cm of the obtained laminate using one high pressure mercury lamp (output 80 W / cm)
The adhesive layer was cured by irradiating with ultraviolet light for 5 seconds. Acrylic pressure-sensitive adhesive layers were formed on both sides of this laminate so that each had a thickness of 50 μm, to give a double-sided adhesive tape.

Example 5 "Asaprene" T-420 [styrene-butadiene-styrene block polymer, manufactured by Asahi Chemical Industry Co., Ltd.] 100
And 1 part by weight of "JSR PB 805" [butadiene resin, manufactured by Japan Synthetic Rubber Co., Ltd.] with 1 part of toluene.
Dissolved in 50 parts by weight, and this, "New Frontier"
An adhesive was prepared by mixing 20 parts by weight of IBA [isobornyl acrylate, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.], 2 parts by weight of benzophenone, and 2 parts by weight of dimethylaminoethanol to prepare a 40-micron-thick polypropylene film on one side. Was applied and dried to form an adhesive layer having a thickness of 20 μm.
A 40-micron-thick polypropylene film was further bonded to this adhesive layer to form a laminate. The obtained laminate was used with one high pressure mercury lamp (output 80 W / cm).
Ultraviolet irradiation was performed under 15 cm for 5 seconds to cure the adhesive layer. Further, a natural rubber-based pressure-sensitive adhesive layer was provided on both sides of this laminate to obtain a double-sided adhesive tape.

Example 6 Example 5 was repeated except that benzophenone and dimethylaminoethanol were omitted from the components of the adhesive used in Example 5.
A laminate was prepared in the same manner as above, and after providing a pressure-sensitive adhesive layer, the adhesive layer was cured by electron beam irradiation with a strength of 3 Mrad.

[0025]

EFFECTS OF THE INVENTION An article in which constituent members are assembled using the laminate of the present invention can be adhered when the plastic films on both sides of the adhesive layer are peeled off at the time of disassembly, for example, when the adhesive strength is larger than the cohesive strength. If the adhesive layer is broken at the part of the adhesive layer and the adhesive strength is smaller than the cohesive strength, it is peeled off at the interface between the adhesive layer and the plastic film and can be easily disassembled into its constituent members. Therefore, it is possible to lose the function of the adhesive tape without requiring a large-scale device or energy such as ultraviolet rays and infrared rays by making an appropriate difference according to the use after the disassembly, the configuration of the article, etc. It will be very useful in terms of global environment protection such as effective use of waste, reuse of products, reduction of industrial waste.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a laminate that is an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an adhesive tape that is another embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a state when the laminate of the present invention is broken.

FIG. 4 is an explanatory view showing another state when the laminate of the present invention is broken.

[Explanation of symbols]

1,1 'plastic film 2 Adhesive layer 3 Adhesive part 4 laminate 5,5 'adhesive layer 6 Adhesive tape

Continued Front Page (72) Inventor Hideyuki Okada 1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation (72) Inventor Hiroshi Yamamoto 1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto (56) Reference JP-A-5-214302 (JP, A) JP-A-3-265679 (JP, A) JP-A-5-269906 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) B32B 1/00-35/00 C09J ^7/ 00-7/04

Claims (6)

(57) [Claims] 1. A plastic film is laminated on both sides of an adhesive layer containing a reactive monomer that can be cured by irradiation of ultraviolet rays and electron beams and a photoreaction initiator, and a plastic film is laminated between the plastic film layer and the adhesive layer. A laminate having a difference in adhesive strength and cohesive strength of the adhesive layer itself. 2. The laminate according to claim 1, wherein the reactive monomer is an acrylic monomer. 3. The laminate according to claim 1, wherein the adhesive strength between the plastic film layer and the adhesive layer is larger than the cohesive strength of the adhesive layer itself. 4. The laminate according to claim 1, wherein the adhesive strength between the plastic film layer and the adhesive layer is smaller than the cohesive strength of the adhesive layer itself. 5. The laminate according to claim 4, wherein the plastic film is a polyester film, a polypropylene film, a polyethylene film, a polyvinyl chloride film, a polyvinylidene chloride film or a polyacrylic ester film. 6. An adhesive film or an adhesive tape having a pressure-sensitive adhesive layer, a hot-melt adhesive layer or a thermosetting adhesive layer provided on one side or both sides of the laminate according to claim 1, 3 or 4.