JP2649636B2 - Adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition which can be widely used for bonding articles such as plastics, in particular, a metal foil (aluminum, copper, stainless steel, etc.) and a plastic film (polyethylene terephthalate, polynaphthalene terephthalate, etc.). The present invention relates to an adhesive composition which is suitably used for bonding.

[0002]

2. Description of the Related Art When a metal foil / polyethylene terephthalate adhesive film is used for radio wave shielding, a part of the metal foil may be cut off for connection with a lead wire or for other reasons, or conversely, a polyethylene terephthalate film may be used.
The part may be cut off. When removing the metal foil, dissolution and removal with a chemical solution, that is, etching is commonly used.However, etching requires time and labor, and there is a problem of waste liquid treatment. There is also a method of putting and stripping. However, according to the method of stripping the metal foil, the metal foil must be peeled cleanly and lightly along the cut, but in general, the adhesive strength between the metal foil and the film is too strong to be peeled off in many cases. On the other hand, when the metal foil is peeled off, there is a problem that the metal foil is easily peeled even when the metal foil has an adhesive strength that is too low to produce a product.
If an adhesive is used to bond the metal foil to the film, the adhesive strength is low before curing (mainly by heating), the metal foil can be easily stripped off, and if cured thereafter, the adhesive strength increases and the metal foil increases. Although there is no accident that peels off, the adhesive before curing is exposed on the film immediately after stripping the metal foil, so when stacking films, the films stick together and the work can not be performed smoothly. There is a problem. Furthermore, when an adhesive is used, the adhesive is likely to undergo a curing reaction even when left at room temperature, and there is a problem that it becomes difficult to peel off the metal foil over time.

On the other hand, when the polyethylene terephthalate film is peeled off from the metal foil / polyethylene terephthalate adhesive film, there are the above-mentioned problems. As an adhesive for a polyethylene terephthalate (hereinafter abbreviated as PET) film, a modified saturated polyester resin is generally used, and good results have also been obtained in bonding metal foil / PET film. However, the adhesive strength is so strong that stripping of the metal foil is difficult. If a vinyl chloride vinyl chloride resin or a butyral resin having a low adhesive strength is used, the metal foil can be easily peeled off, but when the product is used, a failure in which the metal foil is peeled easily occurs.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for temporarily bonding a plurality of films by pressing them at room temperature or low temperature, and for example, when unnecessary portions are cut off, the unnecessary portions are easily peeled off. To provide an adhesive composition having such characteristics that it is difficult for both to adhere to each other even when another film is overlaid thereon, and that the composition is cured by heating to a high temperature to obtain excellent adhesive strength. Aim. Another object of the present invention is to provide a composite sheet bonded with the adhesive composition.

[0005]

According to the present invention, when a specific polyester resin or a combination of a polyurethane resin / epoxy resin / latent epoxy resin curing agent / curing accelerator is used as a component constituting the adhesive composition. It was made based on the knowledge that problems could be solved efficiently. That is, the present invention provides that (a) a crystalline polyester resin or a polyurethane resin, (b) an epoxy resin, (c) a latent epoxy curing agent, and (d) a curing accelerator are dissolved or dispersed in an organic solvent. An adhesive composition is provided. In the present invention, the ratio of the components (a) to (d) can be arbitrarily determined, but the component (a) is 30 to 90 parts by weight, the component (b) is 5 to 60 parts by weight, and the component (c) is 1-2
It is preferable to contain 0 parts by weight and 0.01 to 5 parts by weight of the component (d). These are used by dissolving or dispersing them in an organic solvent so as to have a desired viscosity. Usually, it is preferable to use a solvent so that the solid content concentration is 10 to 50% by weight. As the crystalline polyester resin of the component (a) used in the adhesive of the present invention, a modified polybutylene terephthalate-based resin having a relatively high crystallization rate at Tg of 0 ° C. or less is preferable. Such resins are commercially available as Byron GM-900 and Byron 30P (manufactured by Toyobo Co., Ltd.). As the modified polyurethane resin of the component (a), commercially available resins such as Desmocol 510 and 500 (manufactured by Sumitomo Bayer Urethane Co., Ltd.) can be used. As the epoxy resin of the component (b), a urethane epoxy resin in which a urethane resin and a bisphenol A type epoxy are combined is preferable, and the addition of the urethane resin can lower the initial adhesive strength. Such resins are commercially available under the trade name of Adeka Resin EPU-73 and EPU-6A (manufactured by Asahi Denka Co., Ltd.). Also, bisphenol F type epoxy resin (trade name: Epicoat 807, manufactured by Yuka Shell Epoxy Co., Ltd.) or bisphenol type epoxy resin [Epicoat YX400 Yuka Shell Epoxy Co., Ltd.] can be used.

As the latent epoxy curing agent of the component (c), block polyisocyanates and microcapsule curing agents are preferred. Even those having a high curing temperature, such as acid anhydrides and dicyandiamide, are not very suitable because they show changes over time. The addition of the latent curing agent improves the adhesive strength during heating. Such a curing agent is a phenol block polyisocyanate (trade name Desmodur C)
It is commercially available as T Stable or AP Stable, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and Novacure HS3721 (Nissan Chemical Co., Ltd.). As the curing accelerator of the component (d), a metal-based curing accelerator such as organotin or metal soap such as dibutyltin dilaurate and dibutyltin dioctate is preferable, and is effective in lowering the initial adhesive strength.
Moreover, the adhesive strength after heating does not decrease. It also helps prevent blocking of the adhesive film. Such a hardening accelerator is Nikka Octin Tin (manufactured by Nippon Chemical Industry Co., Ltd.)
It is commercially available. Further, as the organic solvent, dioxane, toluene, methyl ethyl ketone, ethyl acetate, trichloroethylene and the like can be used. In addition to the above components, addition of a filler such as silica (prevention of blocking), addition of a polyemulsion (prevention of blocking), and addition of a surfactant (antistatic and prevention of blocking) are also effective in some cases.

In the present invention, various articles can be bonded using the above-mentioned adhesive composition. Among them, (a) a composite sheet obtained by overlapping a metal sheet and a plastic sheet via the above-mentioned adhesive composition, and (ii) a plastic sheet and a plastic sheet obtained by overlapping via the above-mentioned adhesive composition. And (c) a composite sheet in which a plastic sheet in a laminate of a metal sheet and a plastic sheet and another plastic sheet are overlapped with the above adhesive composition interposed therebetween. Here, examples of the metal sheet include aluminum foil, copper foil, and foils of iron and steel. The thickness can be arbitrarily set, but is preferably about 20 to 100 μm. Examples of the plastic sheet include sheets made of polyester resin, polyvinyl chloride resin, and nylon resin. or,
Laminates such as various FRPs can also be used. When such a plastic sheet having electrical insulation properties is used, the composite sheet of the above (a) and (c) can be suitably used as an electromagnetic wave shielding sheet. The thickness of the plastic sheet can be arbitrarily set.
It is good to be about mm. Further, the amount of the adhesive composition used for bonding the plurality of sheets can be arbitrarily determined, but is preferably about 5 to 50 μm as a dry thickness.

Next, a method for producing a composite film (sheet) according to the present invention will be described using a composite film of a metal foil and a polyester (PET) film as an example. 1) Components (a) to (d) and other components are dissolved or dispersed in an organic solvent to prepare an adhesive solution. 2) An adhesive solution is applied to one surface of a PET film or a metal foil and dried to prepare a film or a metal foil with an adhesive. 3) A film with an adhesive or a metal foil is bonded to a metal foil or a PET film to which no adhesive is applied by 10 to 20.
Lamination is performed at a temperature of about ° C to temporarily adhere the two to each other, thus obtaining the composite film of the present invention. 4) In the present invention, further, an unnecessary portion of the PET film or the metal foil of the composite film is cut with a knife or the like and peeled off. In the present invention, since a specific adhesive composition is used, peeling can be easily performed. In this state, even if a plurality of composite films are superposed, they do not adhere to each other. 5) Next, the adhesive composition is cured by heating to, for example, 60 to 120 ° C. to completely bond the PET film and the metal foil. The composite film thus produced can be widely used for shielding radio waves and electromagnetic waves, and for printed circuit boards. Further, it is also useful for bonding metal foil to plastic moldings and bonding between plastics.

[0009]

As described above, the adhesive composition of the present invention is capable of temporarily bonding a plurality of sheets by pressing them at room temperature or low temperature, for example, when unnecessary parts are cut off, the unnecessary parts are easily peeled off.
In addition, even if another film is stacked on the peeled portion, the two are hardly adhered to each other, and are cured by heating to a high temperature to obtain excellent adhesive strength. Next, the present invention will be described with reference to examples.

[0010]

【Example】

 Example 1 Polybutylene terephthalate resin (trade name Byron)
GM-900, manufactured by Toyobo Co., Ltd.) 80 parts by weight, urethane
Epoxy resin (trade name Adeka Resin EPU-73,
Asahi Denka Co., Ltd.) 20 parts by weight, phenol block poly
Isocyanate (trade name Desmodur CT stave)
10% by weight, manufactured by Sumitomo Bayer Urethane Co., Ltd.
0.2 parts by weight of butyltin dilaurate was added to 330 parts of dioxane
A 25% solid solution was prepared by dissolving in an amount of the solid solution. This
Adhesive solution of 100μm thick polyester film
(Toray's Lumirror 100T-Future PET film
Abbreviated name), after coating and drying to a dry film thickness of about 15 μm,
30μm thick aluminum foil (Toyo Aluminum
Aluminum foil 3EC-III manufactured by Co., Ltd.) using a laminator
(Lamination conditions: room temperature x 14 kg / cm ^Two× 2m / mi
n) Compression bonding to obtain a two-layer film. This aluminum foil
/ Cutting on aluminum foil of PET adhesive film with cutter
Put your eyes and partially wrap the aluminum foil.
I was able to remove it cleanly. This film has 3
The same performance was shown after the menstruation. Example 2 The same adhesive as in Example 1 was applied to an aluminum foil (thickness 30 μm).
m) / PE of PET film (12μm) laminated film
Apply to T film side (dry film thickness about 15μm), 100
Laminate with μm PET film (Lamination conditions
Is the same as in Example 1) to form a three-layer film. This connection
Aluminum / PET laminated film side of three-layer film
Cut a part of the part with a cutter, aluminum / PET
After removing the laminated film, it can be removed neatly.
No adhesive film remains on the peeled 100μm PET side
Did not. Therefore, aluminum / PET laminated film
This three-layer film, which has been partially peeled off, can be stacked
Since there is no adhesive film left in the peeled part,
This is convenient because the problem of blocking does not occur in the part.

Example 3 The same adhesive as in Example 1 was applied to a PET film having a thickness of 100 μm (dry film thickness: about 20 μm), and then laminated with a 35 μm electrolytic copper foil (3ECIII, Mitsui Mining & Smelting Co., Ltd.). The lamination conditions are the same as in Example 1.) Make a cut on the PET film side of this adhesive film with a cutter
When the ET film was removed, it could be removed lightly and neatly. Example 4 The same adhesive as in Example 1 was used except that 2 parts by weight of a polyethylene wax emulsion (trade name: STR anti-wear additive, manufactured by Dainichi Seika) was added. This was applied to a PET film having a thickness of 100 μm in the same manner as in Example 1, and
The peel strength of the unheated product and the heated product after lamination with a μm aluminum foil was measured. In the unheated product, when a cut was made in the aluminum foil, the aluminum foil could be peeled lightly and neatly, and the adhesive remained on the PET film side, but did not block even when these were stacked. Example 5 80 parts by weight of a polyurethane resin (trade name: Desmocol 510, manufactured by Sumitomo Bayer Urethane Co., Ltd.), 20 parts by weight of a urethanized epoxy resin EPU73, 10 parts by weight of phenol block polyisocyanate, and 0.2 part by weight of dibutyltin dioctate Was dissolved in a mixed solvent of 160 parts by weight of toluene and 160 parts by weight of methyl ethyl ketone. This adhesive solution was applied to a 35 μm aluminum foil (dry film thickness: about 15 μm), dried, and then 100 μm PET film (Lumilar 100T) and room temperature. Was laminated. Cut a part of the aluminum foil / adhesive film with a cutter,
When the aluminum foil was peeled off, the adhesive film was lightly cleaned and no adhesive film remained on the PET surface.

Example 6 Polybutylene terephthalate resin (Vylon GM # 9)
00) 100 parts by weight, 10 parts by weight of bisphenol F type epoxy resin (trade name: Epicoat 807, manufactured by Yuka Shell Epoxy Co., Ltd.), 5 parts by weight of phenol block polyisocyanate (Desmodur CT Stable) and a fluorine-based surfactant (Product name Florard FC430
0.1 parts by weight of dioxane 40 (manufactured by Sumitomo 3M Limited)
0 part was dissolved to form an adhesive, applied to a PET film in the same manner as in Example 1, and then laminated with an aluminum foil. Comparative Example 1 An adhesive having a formulation excluding dibutyltin dilaurate from the adhesive of Example 1 was prepared, and an aluminum / PET film laminate was manufactured in the same manner as in Example 1. A part of the aluminum foil was cut and peeled off, but the peeling was heavy and the adhesive remaining on the PET film side from which the aluminum foil had been removed had a strong blocking property and could not be stacked.

Comparative Example 2 An adhesive obtained by removing the urethane epoxy resin and the blocked polyisocyanate from the adhesive of Example 5, that is, an adhesive obtained by adding only dibutyltin dioctate to Desmocol 510, was used. Unheated and heated products (1
(20 ° C. × 10 minutes), the peel strength was too low. Next, Table 1 shows the peel strength of the unheated product and the heated product of the examples and the comparative examples. The peel strength was determined by cutting a 25 mm wide sample from a room temperature laminated product and an adhesive piece heated at 120 ° C. for 10 minutes in a dryer, and measuring the 90 ° and 180 ° peel strength (g / 25 mm) with a crosshead. Speed 200nm / min
(Based on JIS C-6471). It should be noted that only the laminate of Example 2 was heated by heat lamination at 100 ° C.

[0014]

[Table 1] Table 1 Stripping angle Example 1 2 3 4 5 6 Unheated 90 ° 170 250 230 180 50 320 Unheated 180 ° 300 200 350 280 100 460 Heated 90 ° 1200 1000 1600 750 1000 900 Heated product 180 ° 1700 1100 2200 900 1300 1100

[0015]

[Table 2] Table 1 (continued) In addition, the peeling strength of the unheated product and the heated product of the laminated products of Examples 1 to 6 remained almost unchanged after 100 days of aging at room temperature, and the unheated product was significantly heated even after aging. The boring strength was improved, and good performance meeting the purpose of the present invention was shown.

Claims (2)

(57) [Claims] 1. A method in which (a) a crystalline polyester resin or polyurethane resin, (b) an epoxy resin, (c) a latent epoxy curing agent and (d) a curing accelerator are dissolved or dispersed in an organic solvent. Adhesive composition. 2. 30 to 90 parts by weight of component (a), 5 to 60 parts by weight of component (b), 1 to 20 parts by weight of component (c) and 0.01 to 5 parts by weight of component (d). Claim 1 containing
The adhesive composition as described in the above.