JP2010234708A - Decorative sheet and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative sheet and a method for manufacturing the decorative sheet excelling in flatness even if containing a luster pigment with a large grain diameter and a high aspect ratio, hardly causing an appearance failure without impairing a design property, and not foaming in secondary processing. <P>SOLUTION: The method for manufacturing the decorative sheet comprises at least an electron beam curable coating film forming process for applying electron beam curable resin containing short fiber of photo-coloring fiber with a length of 75-3,000 μm in a thickness of 50-250 μm to the surface of a base material film layer; a coating process for coating the electron beam curable coating film with a protective film; and a curing process for irradiating the electron beam curable coating film with electron beams to obtain a cured film. The decorative sheet is obtained by the manufacturing method. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a decorative sheet and a manufacturing method thereof.

  In recent years, paints and decorative sheets have been applied to the surfaces of furniture, joinery, kitchen storage, and other building materials, such as wall paper, air conditioners, televisions, refrigerators, and other home appliances, and automotive interior parts, in particular to enhance the design. Then, a metallic luster is imparted.

  The method using a paint is excellent in that it is easy to apply even if it has a complicated shape. However, when an organic solvent is used, there is a possibility that the working environment is deteriorated and the human body is adversely affected. In the case of a water-based paint, quality control is difficult and manufacturing cost increases due to an increase in extra steps such as a drying step. Furthermore, there is a problem that it is difficult to obtain a surface having excellent flatness such as a mirror surface.

  As a decorative sheet, for example, it is conceivable that a bright pigment is added to a thermoplastic resin, and the sheet is formed into a sheet shape using an extruder, a calendering machine, or the like to obtain a decorative sheet. However, this method has a problem that the particles of the bright pigment are finely crushed during kneading and molding, and the desired designability cannot be obtained.

  There is also a method of obtaining a decorative sheet by printing on a film using an ink containing a bright pigment. However, bright pigments have a larger particle size and a higher aspect ratio than ordinary pigments, so when diverting a printing plate mold, pigment particles are unevenly biased due to plate engraving and doctor streaks are generated. There is a problem that the appearance defect such as erosion is likely to occur and the product defect rate becomes high.

  Further, in a decorative sheet composed of three layers, a decorative sheet containing a luster pigment in an adhesive such as a two-component curable type using an organic solvent constituting an intermediate layer and a method for producing the decorative sheet have been proposed (Patent Document 1). . However, when an adhesive is applied, it also tends to cause poor appearance such as doctor streaks. In addition, when reheating is performed in the secondary processing such as vacuum forming, there is a problem that the residual solvent in the adhesive is vaporized and the decorative sheet is foamed.

JP-A-8-156215

  Accordingly, an object of the present invention is to provide a decorative sheet that has a large particle diameter and does not cause poor appearance without impairing the design even if it contains a high aspect ratio bright pigment, and does not foam during secondary processing. It is to obtain the manufacturing method.

  The decorative sheet of the present invention has a base film layer and a cured coating layer of an electron beam curable resin having a thickness of 50 to 250 μm and containing short fibers of photochromic fibers having a length of 75 to 3000 μm. It is.

  The photochromic fiber is a fiber having a multilayer structure having a coloring effect by light interference in which two kinds of resins having different refractive indexes are alternately stacked, and has a minor axis of 10 to 20 μm and a major axis of 40 μm. It is preferable that it is -70 micrometers.

  Moreover, the electron beam curable coating film formation process which apply | coats the electron beam curable resin containing the short fiber of 75-3000 micrometers in length on the surface of a base film layer with a thickness of 50-250 micrometers. And a coating step of covering the electron beam curable coating film with a protective film, and a curing step of irradiating the electron beam curable coating film with an electron beam to obtain a cured film. It is a manufacturing method.

  The photochromic fiber used in the method for producing a decorative sheet is a fiber having a multilayer structure having a color developing effect due to light interference in which two types of resins having different refractive indexes are alternately stacked, and a minor axis of the fiber cross section. Is a short fiber having a major axis of 40 to 70 μm.

  The decorative sheet of the present invention uses short fibers of photochromic fibers having a length of 75 to 3000 μm as bright pigments, but uses a cured coating layer of an electron beam curable resin having a thickness of 50 to 250 μm. Therefore, a decorative sheet that does not easily cause poor appearance and does not foam during secondary processing is obtained without impairing the design.

  In addition, the photochromic fibers used in the decorative sheet of the present invention are superior in design and flexibility compared to conventional bright pigments, and therefore, the decorative sheet is laminated on various base materials by a three-dimensional molding method such as membrane molding. When processing, the processability is excellent.

  Moreover, according to the manufacturing method of the decorative sheet of this invention, the above decorative sheets can be manufactured.

  Hereinafter, the present invention will be described in detail.

  The base film layer used for the decorative sheet of the present invention is a layer to be applied when the decorative sheet of the present invention is applied to the surface of a member such as a home appliance or a building material.

  The base film layer is made of a thermoplastic resin, and may be colored or uncolored, or may be transparent, translucent, or opaque. When colored, high designability can be obtained by a synergistic effect with the metallic luster derived from the photochromic fibers contained in the cured coating layer. Further, when the cured coating layer and the base sheet are both transparent, the entire decorative sheet can be seen through, so that the design utilizing the expression and characteristics of the member to be attached can be obtained.

  Moreover, the base film layer may have a printed pattern on the surface. The printing pattern uses various inks containing urethane acrylate, vinyl chloride-vinyl acetate resin, etc. as binder components, and the surface of the base sheet layer using methods such as gravure printing, letterpress printing, ink jet printing, reverse roll coating, etc. Print on.

  Specific examples of the thermoplastic resin used for the base film layer include polyester resins such as PET, APET, and PETG, polyolefin resins, and polyvinyl chloride resins. Especially, since it is excellent in post-processability, it is preferable to use the film using PETG which is amorphous. Also, a film (GAG film) in which an amorphous polyethylene terephthalate layer (APET layer) is laminated between two layers made of PETG may be used.

  The thickness of the base film layer is 40 to 500 μm. Preferably it is 50-400 micrometers, and it is especially preferable in it being 80-300 micrometers. If the thickness of the base film layer is 40 μm or more, it has a strength that can sufficiently withstand post-processing. On the other hand, if it exceeds 500 μm, an extra heating time is required at the time of secondary processing, so that the decorative sheet itself is easily damaged and is disadvantageous in price.

  The protective film covering the surface of the decorative sheet of the present invention may be anything as long as the surface is smooth and has peelability from the cured coating layer.

  Specifically, as the protective film, a biaxially stretched polyethylene terephthalate film (hereinafter referred to as “biaxially stretched PET film”), an easily molded polyethylene terephthalate film (hereinafter referred to as “easy moldable PET film”), a polypropylene film. (Hereinafter referred to as “PP film”). Among these, it is preferable to use a biaxially stretched PET film that can make the surface state of the cured coating film layer smoother.

  Note that easy-molding polyethylene terephthalate is a kind of polyethylene terephthalate, and the dicarboxylic acid component of polyethylene terephthalate is terephthalic acid, whereas dicarboxylic acid components include isophthalic acid and / or phthalic acid in addition to terephthalic acid. It is what.

  The protective film is used to form a cured coating film of an electron beam curable resin on the smooth surface, but not only those having a smooth surface, but also fine embossed or uneven printing on the entire surface or partially fine unevenness. You may use what was formed. It is better to use a matte biaxially stretched PET film that gives a matte design with a matte surface, an embossed biaxially stretched PET film that gives an uneven embossed design, or an easily molded PET film. .

  The thickness of the protective film is preferably 12 to 200 μm, more preferably 25 to 100 μm, and particularly preferably 25 to 50 μm. If the thickness of the protective film is 12 μm or more, it is possible to give surface smoothness after peeling, and if it is 200 μm or less, it is easy to handle and is advantageous in terms of price.

  The protective film may be peeled off immediately after production of the decorative sheet, but if it is stored, transported, or secondary processed without peeling, the surface of the decorative sheet can be protected from unexpected scratches.

  The cured coating layer is a layer obtained by curing an electron beam curable composition containing an electron beam curable resin and short fibers of photochromic fibers.

  As an electron beam curable resin, there is an effect of preventing foaming derived from a residual solvent at the time of secondary processing, and since it is excellent in coating properties when forming a cured coating film layer, it does not substantially contain a solvent, It is preferable to use those containing a polymerizable oligomer and a polymerizable monomer.

  Examples of polymerizable oligomers include acrylic oligomers such as urethane acrylate oligomers, polyester acrylate oligomers, epoxy acrylate oligomers, acrylic resin acrylates; allyl ether oligomers, vinyl ether oligomers, allyl urethane oligomers, polyether acrylate oligomers, polyol acrylates. Examples include oligomers and melamine acrylate oligomers.

  Among these polymerizable oligomers, it is preferable to use a urethane acrylate oligomer because flexibility is easily imparted and handling is easy.

  Examples of polymerizable monomers include monofunctional acrylates such as hexyl acrylate, 2-ethylhexyl acrylate, isobornyl acrylate, and isooctyl acrylate; bifunctional acrylates such as 1,6-hexanediol diacrylate and neopentyl glycol diacrylate; trimethylol Polyfunctional acrylates such as propane triacrylate and dipentaerythritol hexaacrylate; and polythiol compounds.

  Among these polymerizable monomers, trimethylolpropane triacrylate is preferably used because it is inexpensive and easily available.

  The content of the electron beam curable resin in the electron beam curable composition is preferably 90 to 99.999% by mass, more preferably 95 to 99.95% by mass, and 98 to 99.9% by mass. Particularly preferred.

  The electron beam curable resin preferably has a viscosity of 5 to 20 Pa · s (25 ° C., the same applies hereinafter). If the viscosity is 5 Pa · s or more, it can be uniformly kneaded and extruded with the short fibers of the photochromic fiber, and coating unevenness is unlikely to occur. If the viscosity is 20 Pa · s or less, uniform coating with a coating thickness of about 50 to 250 μm is possible.

  The photochromic fibers have a length of 75 to 3000 μm, and it is preferable to use short fibers of 150 to 2500 μm. When the length of the short fiber is shorter than 75 μm, the design property is poor, and when the length is longer than 3000 μm, the fibers tend to be entangled with each other and easily clogged during coating.

  Further, the photochromic fiber is a fiber having a multilayer structure having a color developing effect by light interference in which two kinds of resins having different refractive indexes are alternately stacked, and the minor axis of the fiber cross section is 10 to 20 μm and the major axis is 40. The thing of -70 micrometers is preferable. Since the multilayer structure and the aspect ratio are large, the gloss changes, and high designability can be imparted.

  The content of short fibers of the photochromic fiber in the electron beam curable resin composition is preferably 0.01 to 8% by mass, more preferably 0.03 to 5% by mass, and 0.05 to 3%. A mass% is particularly preferred. If content is 0.01 mass% or more, a specific design effect can be provided to a decorative sheet. Moreover, if it is 8 mass% or less, external appearance defects, such as coating nonuniformity and a doctor stripe, are hard to produce.

  In addition, if necessary, the electron beam curable composition includes a light stabilizer (for example, a hindered amine light stabilizer), an antioxidant, an anti-aging agent, a leveling agent, an antistatic agent, and storage stability. Agent, plasticizer, lubricant, inorganic filler, organic filler, metal (composite) oxide fine particles such as titanium oxide, zinc oxide and ITO, UV pigment and UV absorber, UV absorber and near infrared absorber Etc. can also be added.

  The lower limit of the coating thickness of the electron beam curable resin is preferably 3 times, preferably 4 times, the short diameter of the short fibers. If it is too thin, streaks and irregularities are likely to occur on the coated surface. Further, the upper limit of the application thickness of the electron beam curable resin may be a thickness that can impart cosmetic properties, and the cost is increased. Therefore, 250 μm or less, preferably 200 μm or less is sufficient.

  The decorative sheet of the present invention may have a second cured coating layer made of a transparent electron beam curable resin on the cured coating layer. The second cured coating film layer is a layer formed by curing a second electron beam curable composition containing a transparent electron beam curable resin. Here, as a transparent electron beam curable resin, the electron beam curable resin similar to the said cured coating film layer can be used. Even if the second electron beam curable composition is composed only of the electron beam curable resin, short fibers of photochromic fibers having different lengths, a bright pigment, and a color pigment are included in the electron beam curable resin. And what added the other additive may be used.

  An example of the method for forming a decorative sheet of the present invention will be shown below.

  In order to form the decorative sheet of the present invention, an electron beam curable composition in which short fibers of photochromic fibers are uniformly dispersed with a stirrer in an electron beam curable resin is continuously formed on the surface of the base film layer. To form a coating film. Next, the coating film is continuously covered with a protective film, and from this protective film, an electron beam under an appropriate condition is irradiated under a nitrogen gas atmosphere, the coating film is cured to form a cured coating film layer, The decorative sheet of the present invention is used.

  Examples of the application method of the electron beam curable composition include a cast coating method, a roll knife coating method, a die coating method, a reverse roll coating method, a roll coating method, and a gravure coating method. The electron beam curable composition is preferably applied by, for example.

  The decorative sheet of the present invention uses an electron beam curable resin containing short fibers of photochromic fibers, and is applied to the base film by a cast method or the like, so that desirable decorative properties are imparted to the decorative sheet of the present invention. be able to.

  Furthermore, the electron beam curable composition used in the decorative sheet of the present invention is a solventless composition comprising an electron beam curable resin and short fibers of photochromic fibers, and has excellent processability.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
In addition, each decorative sheet obtained in each example was evaluated by the following method.

[Presence or absence of doctor lines]
The decorative sheet obtained in each example was visually observed and evaluated according to the following criteria.
○: No streak is observed.
Δ: Although streaks are recognized, there is no practical problem.
X: A streak is recognized greatly and a practical problem is large.

[Dispersibility]
The decorative sheet obtained in each example was visually observed and evaluated according to the following criteria.
○: Dispersibility of short fibers of photochromic fibers is good.
(Triangle | delta): The dispersibility of the short fiber of a photochromic fiber has some unevenness in the width direction.
X: The short fiber of the photochromic fiber has large entanglement and unevenness.
First, as a base film layer, a 300 μm thick black PETG film (CISR “GSR”) is used, and urethane ink (DIC “XS”) is applied to the substrate by a gravure printing method. A pattern was formed.
Next, 60 parts by mass of electron beam curable resin A (“Art Resin UN-3320HB” manufactured by Negami Kogyo Co., Ltd.) and 40 parts by mass of electron beam curable resin B (“NK Ester A-HD” manufactured by Shin-Nakamura Chemical Co., Ltd.) Mixed, adjusted to about 10 Pa · s (25 ° C.), 2 parts by weight of photochromic fiber short fibers (fiber short diameter 17 μm, long diameter 70 μm, length 1000 μm, Teijin Fibers Ltd. “Morphotone”) And were uniformly dispersed with a stirrer to obtain an electron beam curable composition.
On the printed pattern, the obtained electron beam curable composition was applied to a thickness of 75 μm with a die coater to form a coating film.
Next, a PET film having a thickness of 75 μm (“SA75” manufactured by Unitika) was continuously coated on the coating film as a protective film.
Furthermore, from above the protective film, an electron beam is irradiated under conditions of an acceleration voltage of 300 eKV and a dose of 70 KGy in a nitrogen gas atmosphere, the electron beam curable composition is cured to form a cured coating film layer, and a decorative sheet is formed. Each evaluation was performed about the obtained decorative sheet. The evaluations of “presence / absence of doctor streak” and “dispersibility” were both “good”.

First, as a base film layer, a black PETG film having a thickness of 300 μm (“GSR” manufactured by C.I. Kasei) was used.
Next, an electron beam curable resin (“Aronix M-7100” manufactured by Toa Gosei Co., Ltd.) and a photochromic fiber short fiber (fiber short diameter 17 μm, long diameter 70 μm, length 2000 μm, Teijin Fibers Ltd. “Morphotone”) 2 parts by mass were mixed and uniformly dispersed with a stirrer to obtain an electron beam curable composition adjusted to a viscosity of about 9 Pa · s (25 ° C.).
On the said base film layer, the obtained electron beam curable composition was apply | coated so that it might become thickness of 100 micrometers with a die-coater, and the coating film was formed.
Next, the coating film was continuously coated with a 75 μm thick biaxially stretched PET film (“SA75” manufactured by Unitika), which is a protective film.
Further, from above the protective film layer, an electron beam is irradiated under the conditions of an acceleration voltage of 250 eKv, a dose of 70 KGy, and a speed of 10 m / min in a nitrogen gas atmosphere to cure the electron beam curable composition to form a cured coating film layer. Each evaluation was performed about the decorative sheet obtained by forming the decorative sheet and peeling off the protective film. The evaluations of “presence / absence of doctor streak” and “dispersibility” were both “good”.

First, as a base film layer, a white PETG film (CISR Kasei, GSR) having a thickness of 150 μm is used, and urethane ink (DIC, XS) is applied thereto by a gravure printing method, and a printed pattern is formed. Formed.
Next, an electron beam curable resin (“Aronix M-7100” manufactured by Toa Gosei Co., Ltd.) and a photochromic fiber short fiber (fiber short diameter 17 μm, long diameter 70 μm, length 2000 μm, manufactured by Teijin Fibers Limited, “Morphotone” 2) 2 parts by mass were mixed and uniformly dispersed with a stirrer to obtain an electron beam curable composition having a viscosity of about 9 Pa · s (25 ° C.).
On the printed pattern, the obtained electron beam curable composition was applied with a die coater to a thickness of 100 μm to form a coating film.
Next, the coating film was continuously coated with a 75 μm-thick PET film (“S75” manufactured by Unitika) as a protective film.
Further, the protective film layer is irradiated with an electron beam under the conditions of an acceleration voltage of 300 eKV and a dose of 70 KGy in a nitrogen gas atmosphere, and the electron beam curable composition is cured to form a cured coating film layer to form a decorative sheet. And each evaluation was performed about the obtained decorative sheet. The evaluations of “presence / absence of doctor streak” and “dispersibility” were both “good”.

[Comparative Example 1]
A decorative sheet in the same manner as in Example 1 except that the short fiber of the photochromic fiber (fiber short diameter 17 μm, long diameter 70 μm, length 4000 μm, manufactured by Teijin Fibers Ltd., “Morphotone”) was changed. Formed. As for evaluation of the obtained decorative sheet, “presence / absence of doctor streak” was Δ, and evaluation of “dispersibility” was x.

[Comparative Example 2]
In Example 2, a decorative sheet was formed in the same manner as in Example 2 except that the electron beam curable composition was coated with a die coater so as to have a thickness of 30 μm. As for evaluation of the obtained decorative sheet, “existence of doctor streak” and evaluation of “dispersibility” were both x.

  The decorative sheet of the present invention is excellent in design, and can be used for kitchen storage doors, home appliances, and the like.

  Moreover, since the decorative sheet of the present invention contains short fibers of photochromic fibers having a specific length in the cured coating layer, it is excellent in dispersibility and design.

Claims (5)

    A decorative sheet having a base film layer and a cured coating layer of an electron beam curable resin having a thickness of 50 to 250 μm and containing short fibers of photochromic fibers having a length of 75 to 3000 μm.     The photochromic fiber is a fiber having a multilayer structure having a coloring effect by light interference in which two kinds of resins having different refractive indexes are alternately stacked, and has a minor axis of 10 to 20 μm and a major axis of 40 μm. The decorative sheet according to claim 1, which is a short fiber of ˜70 μm.     The decorative sheet according to claim 1, wherein the base film layer has a printed pattern. A coating film forming process for obtaining a coating film by applying an electron beam curable resin containing a short fiber of a photochromic fiber having a length of 75 to 3000 μm on the surface of the base film layer to a thickness of 50 to 250 μm; ,
A coating step of coating a protective film on the coating film;
A curing step of irradiating the coating film with an electron beam;
A method for producing a decorative sheet, comprising:   The photochromic fiber is a fiber having a multilayer structure having a coloring effect by light interference in which two kinds of resins having different refractive indexes are alternately stacked, and has a minor axis of 10 to 20 μm and a major axis of 40 μm. The method for producing a decorative sheet according to claim 4, which is a short fiber of ˜70 μm.