JPH0454580B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a decorative sheet having excellent solvent resistance, heat resistance, adhesiveness, etc.

Conventionally, decorative sheets are known in which a pattern layer, a white coating layer (hidden layer), and an adhesive layer are sequentially formed on one side of a plastic film. This decorative sheet is applied by pressure bonding or thermocompression bonding to the base material to which it is to be bonded. Alternatively, as a decorative sheet, you can use it without an adhesive layer.
When laminating a decorative sheet to a base material, a method is also known in which an adhesive is applied to the base material or the decorative sheet and the adhesive is pressure-bonded. The adhesive used here is an adhesive using a thermoplastic resin or a curable resin, and with an adhesive mainly composed of a thermoplastic resin, the decorative sheet is bonded by thermocompression bonding. Examples of the thermoplastic resin include vinyl resin, acrylic resin, polyamide resin, and rubber resin. Decorative sheets laminated using adhesives mainly composed of thermoplastic resins generally have poor heat resistance and solvent resistance, and furthermore, adhesive properties are not necessarily sufficient. Therefore, the reality is that their use in substrates that require these physical properties, such as metal surfaces, is limited.

Furthermore, adhesives using curable resins do not have sufficient shelf life as decorative sheets, and the decorative sheet provided with the adhesive must be laminated to a base material before the adhesive hardens. Therefore, the reality is that they generally do not have a long shelf life. As this curable resin, urethane resin or the like is used.

Note that a transfer painting method disclosed in Japanese Patent Application Laid-Open No. 57-49591 is also known. Although this method has the advantage of excellent workability, it involves the work of peeling off the base sheet (plastic film), and the plastic film that is the base sheet is generally difficult to reuse, so it ends up being discarded. However, the cost of the plastic film and its specific gravity in the decorative sheet are relatively high, and as a result, this transfer method poses a cost problem.

The present invention utilizes the plastic film as a protective layer by laminating the transparent plastic film to the base material and using it as it is without peeling it off, and furthermore, it has excellent storage stability as a decorative sheet.
The present invention also relates to a decorative sheet from which a decorative material having excellent heat resistance, solvent resistance, and adhesiveness can be obtained.

That is, in the present invention, a transparent plastic film (A) is sequentially coated with an adhesive layer (B), a pattern layer (C), and a concealing layer (D).
and a decorative sheet provided with a radiation-curable adhesive layer (E). Further, the adhesive layer (B) is a urethane-based curable adhesive, the concealing layer (D) is a radiation-curable white coating layer, and the radiation-curable adhesive layer (E) is an ethylenically unsaturated double layer. It is a decorative sheet containing 10 to 90% by weight of monomers and/or prepolymers having bonds, and 10 to 90% by weight of resins having no ethylenically unsaturated double bonds.

The decorative sheet of the present invention has the basic composition of (A)/(B)/(C)/(D)/(E), and has two or more pattern layers of (C), (D ) may be constructed as a decorative sheet having two concealing layers.

The transparent plastic film (A) preferably has excellent solvent resistance and heat resistance, and may be transparent enough to allow the pattern layer (C) to be seen through. For example, various plastic films such as polyester film, nylon film, cellophane film, polyethylene film, polypropylene film, and polyvinyl butyral film can be used. Preferred is polyethylene terephthalate film. By using a plastic film with excellent solvent resistance and heat resistance, the obtained decorative material has excellent solvent resistance and heat resistance. Incidentally, pigments and the like may be added to the plastic film within a range that does not impede transparency.

As the adhesive layer (B), a urethane-based curable resin or a radiation-curable resin is used.

A urethane-based curable resin or a radiation-curable resin as the adhesive layer (B) is coated on the transparent plastic film (A) as a coating composition together with a solvent and various additives. Note that when a thermosetting resin is used, it is thermoset during or after the production of the decorative sheet or before or after radiation irradiation after pasting the decorative sheet.

Furthermore, the adhesive layer (B) may be a radiation-curable adhesive described later.

As the pattern layer (C), a printed layer formed by various types of printing such as gravure printing, offset printing, flexo printing, and letterpress printing, or a pattern layer formed by partial metal vapor deposition can be used. In the case of the printing layer, various conventionally used inks can be used as they are, and radiation-curable inks may also be used.

The pattern layer can be formed on the adhesive layer (B) by various printing methods such as gravure printing, offset printing, and screen printing. Further, the pattern layer can be provided by a conventionally known mold vapor deposition method, and may be partially vapor deposited or a combination of printing and vapor deposition.

The hiding layer (D) is a colored coating layer.
The colored coating layer is generally white (white coating layer). The type of resin for the coating layer is preferably a curable resin, and preferably a radiation curable resin. The coating layer is formed by transparent plastic film (A) / adhesive layer (B) / pattern layer (C).
To print or paint with ink or paint on. If it contains a solvent, pre-dry it.

Furthermore, when the hiding layer is a radiation-curable resin composition, (E) can be omitted.

As the radiation-curable adhesive layer (E), electron beam,
It is an adhesive layer that can be cured by radiation, α-rays, etc., and curing hardly progresses unless it is irradiated with radiation, so it does not have the disadvantages in workability that thermosetting types do. Furthermore, although radiation is irradiated after adhesion to a base material, sufficient curing can be achieved even if there is a concealing layer, for example.

As the adhesive layer (E), a prepolymer and/or monomer having one or more ethylenically unsaturated bonds is used. Examples of prepolymers include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polyol acrylate, melamine acrylate, polyester methacrylate, epoxy methacrylate, urethane methacrylate, polyether methacrylate, polyol methacrylate, melamine methacrylate, unsaturated polyester resin, etc. It is. Examples of monomers include ethylene glycol diacrylate, propylene glycol diacrylate, 1,6-hexane diol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, ethylene glycol dimethacrylate, and propylene glycol diacrylate. These include methacrylate, diethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, and the like.

In addition to the prepolymer and/or monomer, an organic solvent, a polymerization inhibitor, a pigment, etc. can be added to the radiation-curable resin composition as needed to make a coating composition suitable for various coating methods. In the present invention, in order to maintain good adhesion to objects to be adhered, such as metal surfaces, it is preferable to use a radiation-curable resin composition mainly consisting of a prepolymer and using no or a small amount of monomer. or prepolymers and or monomers 10-90
Compositions consisting of 10 to 90% by weight of polymers having no ethylenically unsaturated bonds are also effective.
Examples of polymers without ethylenically unsaturated bonds include acrylic resin, polyamide resin, polyester resin, urethane resin, cellulose resin, epoxy resin, vinyl acetate resin, vinyl chloride resin, petitral resin, poval resin, synthetic rubber, and ethylene resin.
Vinyl acetate resin, etc. After coating this adhesive layer (E), it can be pre-dried to remove the solvent if necessary.

Next, an example of a method for manufacturing a decorative board using the decorative sheet of the present invention will be described.

Press the adhesive layer (E) of the decorative sheet so that it is in contact with the base material that is the transfer target. As an example of the pressure bonding method, the transparent plastic film of the decorative sheet is pressure bonded to the adherend from the A side using a heated press plate or roll if necessary.

After crimping, at least radiation is irradiated.
The radiation may be an electron beam, an X-ray, or a γ-ray, and preferably an electron beam. Scan type and curtain type devices are known as electron beam accelerators, but low accelerating voltage types may also be used. For example, energy
The Electro Curtain type manufactured by Science Corporation is preferably used, and the temperature radiation dose is usually about 0.5 to 20 Mrad. Moreover, irradiation can also be performed in an inert gas atmosphere. The objects to be adhered to include various metal plates such as iron plates, stain-free steel plates, zinc plates, copper plates, and aluminum plates, metal containers such as cans, various plastic molded products such as plastic sheets and plastic containers, paper, various types of wood, and base plates. etc.

Next, the present invention will be explained by examples. In the examples, "parts" and "%" refer to parts by weight and % by weight.

Example 1 The following composition was coated on one side of a 12μ thick transparent polyethylene terephthalate film using a bar coater using 40 parts of Hytaloid 3206B, 10 parts of Coronate-L, and 50 parts of methyl ethyl ketone to a uniform film thickness of 5μ over the entire surface. After coating, it was dried and cured at 120°C for 5 minutes. A pattern was gravure printed thereon using gravure ink to form a pattern layer. next
After drying at 80°C for 10 minutes, a two-component urethane curing type with the following composition: Hytaloid 3206B (polyester resin manufactured by Hitachi Chemical Co., Ltd.) 25 parts Coronate L (polyisocyanate compound manufactured by Nippon Polyurethane Co., Ltd.) 5 parts Titanium oxide 25 parts Methyl ethyl ketone 45 Apply a white coating layer of 10μ using a bar coater.
The film was formed by coating to a film thickness of . after that,
Post-cure was carried out at 40°C for 2 days. Next, the following composition vinyl chloride-vinyl acetate copolymer (Vinylite)
VMCH (manufactured by Union Carbide, USA) 30 parts oligoester acrylate (Aronix M-
6400X (manufactured by Toagosei Kagaku Kogyo Co., Ltd.)) An electron beam curable resin composition having a composition of 10 parts methyl ethyl ketone 30 parts toluene 30 parts was applied to a film thickness of 5 μm.

Using this decorative sheet, the decorative sheet was laminated onto a stain-free steel plate using a laminator at 120°C and bonded under heat. Next, using a curtain type energy science electron beam irradiation device under a nitrogen gas atmosphere from the polyester film side,
It was cured by irradiating it with an electron beam at 160 KV and 4 mA to a dose of 5 Mrad. The decorative sheet could be attached to the stain-free steel plate using strong adhesive.

The above test results for the electron beam cured decorative sheet board are as follows: Lamination property: Good visual judgment Adhesion (after boiling water): 100/100 in cellophane tape goblin test Good boiling water resistance: 100℃, 30 minutes As a result of immersion in boiling water,
Good with no change.

Solvent resistance: Good, withstands most solvents.

Refractive property: Withstands bending of 2m/m diameter.

Pencil hardness: 4H or higher.

Retortability: Good with no change in retort test at 120℃ for 30 minutes.

As mentioned above, good results were shown.

Example 2 The urethane-based curable adhesive layer shown in Example 1 was formed to a thickness of 5 μm on a transparent polyethylene terephthalate film having a thickness of 12 μm using the same method. After forming a pattern layer thereon using the same method as in Example 1, a white coating layer made of an electron beam curable resin having the same composition as in Example 1 was formed to a thickness of 10 μm, and on top of that a pattern layer with the following composition was formed. An electron beam curable resin composition was coated using 35 parts of Vylon 200, 15 parts of Aronix M-6400X, 30 parts of methyl ethyl ketone, and 30 parts of toluene to give a film thickness of 5 μm, and dried at 120° C. for 1 minute.

A decorative sheet was laminated onto stain-free steel under the same conditions as in Example 1 and cured with electron beams.
The obtained decorative board showed good properties similar to those of Example 1.

Example 3 As a result of carrying out the same method as in Example 4 using a transparent polypropylene film instead of the transparent polyethylene terephthalate film, good results similar to those in Example 1 were obtained.

Claims (1)

[Claims] 1. A transparent plastic film (A), an adhesive layer (B) made of a urethane-based curable resin or a radiation-curable resin, a pattern layer (C), and a urethane-based curable or radiation-curable resin. A decorative sheet comprising a concealing layer (D) which is a white coating layer and a radiation-curable adhesive layer (E). 2. The radiation-curable adhesive layer (E) contains 10 to 90% by weight of monomers and/or prepolymers having ethylenically unsaturated double bonds, and 10 to 90% by weight of resins having no ethylenically unsaturated double bonds. A decorative sheet according to claim 1.