JPH04219265A - Manufacture of decorative sheet - Google Patents

Abstract

PURPOSE:To provide a method for the manufacturing the above decorative sheet having a good appearance and a uniformly hardened layer. CONSTITUTION:At least either of a base sheet or release film is coated with a hardening ink in a larger amount than required in their lamination, an excessive ink is extruded therefrom when they are pressed together between the opposing forces of a pair of rolls to form the ink banks, thereby preventing the entry thereinto of air bubbles or the like, the resulting laminate is further pressed and hardened, and then the release film is peeled off to give a shape thereto, whereby a decorative sheet having a good appearance and a uniformly hardened layer can be manufactured efficiently.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a decorative sheet, and more particularly to a method for producing a decorative sheet having a good appearance and a homogeneous cured layer.

0002

BACKGROUND OF THE INVENTION Decorative sheets generally consist of a base sheet laminated with a pattern layer, a hardened layer (protective layer), and the like.

[0003] As the above-mentioned cured layer, there are those using so-called solvent-volatile film-forming resins such as acrylic resins, rubbers, and vinyl resins, and resins that can be cured by ionizing radiation such as ultraviolet rays or electron beams. A desired surface pattern is applied to this cured layer in advance by a molding technique.

[0004] As a method for manufacturing such a decorative sheet, a curable ink in an amount necessary for lamination is applied to at least one of a laminated base sheet and a releasable film having a desired surface pattern, and then a nip roll or the like is applied. A common method is to press the film in the gap between the rolls, cure the ink, and then peel off the releasable film and perform molding.

However, this method has a problem in that air bubbles are likely to be mixed into the ink layer when the applied ink is uneven on the surface or when the ink is laminated into a thick film.

[0006] If air is mixed into the ink layer, not only will it be impossible to obtain a decorative sheet having a cured layer with a uniform and good appearance, but also the air will act as a reaction inhibitor when curing the ink after lamination, causing the ink to harden. Problems may arise, such as insufficient capacity.

[0007] Accordingly, an object of the present invention is to provide a method for producing a decorative sheet that is free from air bubbles, has a good appearance, and has a homogeneous cured layer.

[0008]

[Means for Solving the Problems] As a result of intensive research in view of the above object, the present inventors applied a larger amount of curable ink than necessary for lamination to at least one of the base sheet and the release film. Then, when pressing with a pair of rolls, the pressing force pushes out excess ink,
By forming a pool of ink, you can prevent air bubbles from entering.
Furthermore, the inventors discovered that a decorative sheet having a good appearance and a homogeneous cured layer could be obtained by molding the sheet by peeling off the release film after pressing and curing, and the present invention was conceived based on this finding.

That is, the method for producing a decorative sheet of the present invention includes applying a curable ink to at least one of a base sheet and a release film, pressing and laminating them with a pair of rolls, and curing the curable ink. After that, the amount of the curable ink is adjusted to be larger than the amount required for lamination using a release film, and the curable ink is removed by the pressing force of the pressure bonding at the entrance of the gap part of the roll. It is characterized by preventing air from getting mixed in by pushing out the excess amount and forming a pool of ink.

The present invention will be explained in detail below. In the present invention, the base sheet may be any material used as a base material for ordinary decorative materials, such as polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate/isophthalate copolymer, polyethylene, polypropylene, etc. , polyolefin resins such as polymethylpentene, polyvinyl fluoride, polyvinylidene fluoride, polyfluoroethylene resins such as polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, nylon-6, nylon 6,6, etc. Polyamide, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, ethylene/vinyl acetate copolymer, ethylene/vinyl alcohol copolymer, polyvinyl alcohol, vinyl copolymer such as vinylon, cellulose such as cellulose triacetate, cellophane, etc. based resin, methyl poly(meth)acrylate, ethyl poly(meth)acrylate, ethyl polyacrylate,
A single layer of a film or sheet of an acrylic resin such as polybutyl acrylate, a film or sheet of various synthetic resins such as polystyrene, polycarbonate, polyarylate, polyimide, etc. or a composite of each of the above base materials can be used.

[0011] The thickness of the base sheet is generally 5 to 200 μm.
m, more preferably 10 to 100 μm. If the base sheet exceeds 200 μm, the decorative sheet will become too thick.

[0012] Usually, a pattern layer, a printed layer, a colored layer, etc. are provided on the base sheet as necessary.

The printing layer, colored layer, and pattern layer are printed with ink, and the type of ink may be selected as appropriate depending on the intended use, but conventionally known inks, such as dyes or pigments added to the ink vehicle, are used. Optionally add additives such as plasticizers, stabilizers, waxes, greases, desiccants, auxiliary desiccants, curing agents, thickeners, dispersants, fillers, etc., and add solvents or diluents. It is possible to use an ink obtained by adding the compound and sufficiently kneading it.

Vehicles used in the above ink include various oils and fats such as linseed oil, soybean oil, and synthetic drying oils, natural resins such as rosin, copal, dammar, hardened rosin, rosin ester, and polymerized rosin, or processed resins. Resins, synthetic resins such as rosin-modified phenolic resin, 100% phenolic resin, maleic acid resin, alkyd resin, petroleum resin, vinyl resin, acrylic resin, polyamide resin, epoxy resin, amino alkyd resin, nitro resin Cellulose derivatives such as cellulose, ethyl cellulose, and cellulose acetate, derivatives such as chlorinated rubber and cyclized rubber, and other materials such as glue, casein, dextrin, and zein can be used.

[0015] As a method for printing the above-mentioned ink on the base sheet, ordinary printing methods such as gravure printing, dry offset printing, letterpress printing, and silk screen printing can be used, and drawing may also be used. do not have. The thickness of the above printed layer, colored layer, and pattern layer is usually 0.5~
It is about 10 μm.

[0016] The releasable film used in the method of the present invention can basically be made of the same material as the above-mentioned base sheet, but it is preferably one that has excellent releasability from the curable ink described below. Since this release film also serves as a molding film for applying the curable ink to the coating film, which will be described later, a film with a surface that corresponds to the desired gloss or unevenness of the coating film surface is used. That is, when a mirror-smooth coating film is required, a mirror-smooth film is used, when a matte coating film is required, a matte surface film is used, and when an uneven coating film is required, a textured film or an embossed film is used.

[0017] As the shape of the aperture of the embossed film, various types of well-known unevenness and gloss can be used, such as those that imitate the uneven shape of natural materials such as wood grain, stone grain, cloth grain, sand grain, etc.; Examples include symbols, lines, various other abstract patterns, and combinations of various matte patterns and mirror gloss.

[0018] Note that a parallel line is a collection of uneven shapes that include unevenness or grooves that form a group of parallel straight lines or a group of curved lines in a closed curved area, and it is a collection of uneven shapes that include unevenness or grooves that form a group of parallel straight lines or a group of curved lines. The angles formed by adjacent groups of straight lines or curved lines all have different shapes. This shape has a design feature in that each closed area looks like a pattern with a different gloss, and the gloss of each closed area changes depending on the parallax. In particular, in order to recognize parallel straight lines or groups of curves as a pattern of changes in gloss, the depth and interval of the lines should be 0.1 to 100 μm, and the angle formed by the directions of adjacent groups of straight lines or curves should be It is desirable that the angle is 5° or more. In order for the angle formed by the directions of adjacent groups of straight lines or curved lines to be 5 degrees, four types of angles are necessary and sufficient conditions from the theorem of the four-color problem in topology.

Further, the curable ink used in the present invention is not particularly limited, and can be cured by so-called solvent-volatile film-forming resins such as acrylic resins, rubbers, and vinyl resins, and by ionizing radiation such as ultraviolet rays or electron beams. Although ultraviolet and electron beam curable resins such as resins, various organic and inorganic inks, etc. can be used, it is preferable that the viscosity thereof at the time of lamination is 50,000 centipoise or less. If the viscosity of the ink exceeds 50,000 centipoise, the ink will not be extruded well during lamination, making it easy for air to get mixed in or making it difficult to control the coating thickness.

[0020] As such a curable ink, an ionizing radiation curable resin is preferable. Such resins include prepolymers or oligomers having ethylenically unsaturated bonds in their molecules, such as unsaturated polyesters, various acrylates such as polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polyol acrylates, and melamine acrylates. , polyester methacrylate, polyether methacrylate, polyol methacrylate, various methacrylates such as melamine methacrylate, and optionally a monomer having an ethylenically unsaturated bond in the molecule, such as styrene, α-methylstyrene. Styrenic monomers such as methyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, butoxyethyl acrylate, butyl acrylate, methoxybutyl acrylate, acrylic esters such as phenyl acrylate, methyl methacrylate , ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate, ethoxymethyl methacrylate, phenyl methacrylate, methacrylic acid esters such as lauryl methacrylate, unsaturated carboxylic acid amides such as acrylamide and methacrylamide, acrylic acid-2- (N,
N-diethylamino)ethyl, methacrylic acid-2-(N
, N-dimethylamino)ethyl, acrylic acid-2-(N
, N-dibenzylamino)ethyl, methacrylic acid (N,
N-dimethylamino)methyl, acrylic acid-2-(N,
Substituted amino alcohol esters of unsaturated acids such as N-diethylamino)propyl, ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexane diol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate Polyfunctional compounds such as acrylate, dipropylene glycol diacrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate, and/or polythiol compounds having two or more thiol groups in the molecule, such as trimethylol A mixture of propane trithioglycolate, trimethylolpropane trithiopropylate, pentaerythritol tetrathioglycolate, etc. is used. The above-mentioned compounds can be arbitrarily mixed to form a coating composition, but in order to have appropriate coating suitability, the prepolymer or oligomer may be mixed with 5%.
It is preferable that the amount of the monomer and/or polythiol compound be 95% by weight or less.

[0021] In order to prevent the above-mentioned compound from curing before irradiation with ultraviolet rays or electron beams, a polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, or benzoquinone may be added as a stabilizer to the coating composition. . In addition, when the coating composition is an ultraviolet curable type, acetophenones, benzophenones, Michler benzoyl benzoate, α
- Amyloxy ester, tetramethylthiuram monosulfide, thioxanthone, and a photosensitizer such as n-butylamine, triethylamine, tri-n-butylphosphine, etc. are used in combination.

Furthermore, if high flexibility or shrinkage resistance is required after curing, an appropriate amount of a thermoplastic resin such as a non-reactive acrylic resin or various waxes may be added to the curable composition. These demands can be met by adding . In order to maintain the surface hardness of the protective layer, the amount of thermoplastic resin added is 30% by weight or less.

The decorative sheet of the present invention using such a base sheet, a release film, and a curable ink will be explained.

FIG. 1 is a schematic diagram showing a method for manufacturing a decorative sheet according to an embodiment of the present invention. The apparatus shown in FIG. 1 includes a pair of nip rolls 1 and 2, a coating roll 3, and a paint roller 5 containing a curable ink 4.

In such an apparatus, after printing a desired pattern etc. on one of the films, for example, the base sheet 6, the film is passed between the nip roll 1 and the coating roll 3, and then the film is passed through the gap between the nip rolls 1 and 2. Department. At this time, since the surface of the coating roll 3 is coated with the curable ink 4 in the paint grain 5, the base sheet 6 reaches the entrance of the gap between the nip rolls 1 and 2 after the ink 4 is applied. It turns out.

Here, the coating roll 3 is adjusted so that the amount of ink 4 applied to the base sheet 6 by the coating roll 3 is greater than the amount of ink required for lamination.
Adjust the gap between and nip roll 1. Further, the rotation direction of the coating roll may be the same direction or the opposite direction to the flow direction of the base sheet.

On the other hand, the other film, for example, the releasable film 7 having a desired surface roughness or gloss, is fed from the nip roll 2 side to the entrance of the gap portion.

The base sheet 6 and the release film 7 fed to the entrance of the gap are pressed by the nip rolls 1 and 2 and laminated together. At this time, since an amount of ink greater than the amount required for lamination is applied, the excess ink is pushed out to the entrance of the gap portion by the pressing force, and an ink reservoir 8 is formed there.

By forming the ink reservoir 8 in this manner, the contact surface between the base sheet 6 and the release film 7 is completely covered with ink during lamination. Therefore, both films can be laminated without coming into contact with air, and air can be prevented from entering the ink layer.

In this embodiment, since the ink reservoir 8 is provided below the roll gap, when the ink in the ink reservoir 8 accumulates to a certain extent, the ink reaches as indicated by the dashed arrow in FIG. , drip. Therefore, if the excess ink is collected and reused, such as by collecting it with the paint roller 5 as in this embodiment, it is also economical.

The amount of ink applied can be adjusted by adjusting the nip rolls 1 and 2 to obtain the desired ink layer thickness depending on the thickness of the base sheet 6 and the release film 7 and the ink used. This can be done by setting a gap.

After laminating the base sheet 6 and the releasable film 7 as described above, the ink is cured using a drying device or curing means (not shown) such as ultraviolet rays or electron beams, and then the releasable film 7 is laminated. A decorative sheet can be obtained by peeling off the film.

[0033]

EXAMPLES The present invention will be explained in more detail with reference to the following specific examples. Example 1 60 parts by weight of urethane acrylate (PR-202: trade name, manufactured by Mitsubishi Kasei Corporation) and urethane acrylate (
Viscoat 190: Product name, Osaka Organic Chemical Industry Co., Ltd.
40 parts by weight of the mixture was mixed with 40 parts by weight of the ink (manufactured by the Company) and heated to 50°C to adjust the viscosity to 500 centipoise to prepare a curable ink. This ink is extruded to a thickness of 200 μm using an extrusion nozzle method.
The base sheet (vinyl chloride film with a stone pattern printed on it) was coated in an amount larger than that required for lamination. Immediately thereafter, an ink reservoir was formed and a releasable film was laminated using the method shown in FIG.

[0034] The releasable film has a thickness of 25 μm.
A coated matte film (release mat type 8: trade name, manufactured by Kimoto Co., Ltd.) that had been subjected to matte treatment was used. Further, the gap between the nip rolls was set to 230 μm.

After lamination, an electron curtain type electron beam (EB) irradiation device (9 in FIG. 2: manufactured by ESI)
The electron beam was 5 Mra at an accelerating voltage of 230 kV.
d irradiation to cure the coating film. After curing, the releasable film was removed, and the thickness of the cured coating was measured and visually checked for the presence or absence of air infiltration.
The coating film had a uniform thickness of 5 μm and no air was observed in the coating. Moreover, the pattern layer was beautiful and the surface was evenly matted.

Comparative Example 1 In Example 1, a releasable film was laminated without forming an ink pool. After lamination, the ink was cured by electron beam (EB) in the same manner as in Example 1. After curing, the releasable film was removed and the cured coating film was visually checked to see if air had been mixed in. It was found that some air had been mixed in on the surface and inside of the cured coating film. The cured portions were insufficiently cured, and the desired uniform film could not be obtained.

[0037]

Effects of the Invention As detailed above, according to the method of the present invention, at least one of the base sheet and the release film is coated with a curable ink in an amount larger than that required for lamination, and a pair of rolls When crimping is performed, excess ink is pushed out by the pressing force to form a pool of ink, which prevents air bubbles from entering the ink. By molding, a decorative sheet having a good appearance and a homogeneous cured layer can be efficiently produced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a laminating method according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a laminating method according to another embodiment of the present invention.

FIG. 3 is a schematic diagram showing a laminating method according to another embodiment of the present invention.

[Explanation of symbols]

1, 2...Nip roll 3...Coating roll 4... Ink 5...Paint roughness 6...Base sheet 7...Laminating film 8... Ink pool 9...Electron beam curing device

Claims (3)

[Claims] 1. A curable ink is applied to at least one of a base sheet and a release film, and the sheets are laminated by pressure bonding with a pair of rolls. After the curable ink is cured, the release film is peeled off. In the method for manufacturing a decorative sheet, the amount of the curable ink is adjusted to be greater than the amount required for lamination, and the excess of the curable ink is removed at the entrance of the gap portion of the roll by the pressing force of the crimping. A method for producing a decorative sheet, characterized in that air is prevented from being mixed in by extruding an amount of ink to form a pool of ink. 2. The method for producing a decorative sheet according to claim 1, wherein the curable ink is an ionizing radiation curable ink. 3. The method for producing a decorative sheet according to claim 1, wherein the curable ink has a viscosity of 50,000 centipoise or less.