JP2006088349A - Decorative sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily provide a decorative sheet having flexibility more excellent than that of a conventional polypropylene decorative sheet while having abrasion resistance, scratch resistance, weatherability, chemical resistance and the like, hard to cause whitening or cracking at bending processing and excellent in design properties. <P>SOLUTION: In the decorative sheet wherein at least a base material sheet comprising a non-vinyl chloride material, a concealing pattern layer and a single or a plurality of transparent polypropylene resin layers are laminated in this order, the resin used at least one of the transparent polypropylene resin layers is homopolypropylene of which the degree of crystallization prescribed by a pentad ratio is 80% or below and the melt flow rate prescribed by JIS-K6760 of the transparent polypropylene resin layer is 2-40 g/10 min. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a decorative sheet mainly made of a polyolefin-based material, among decorative sheets mainly made of a thermoplastic resin, mainly used for surface decorations such as entrance doors and curtain rails of buildings. is there.

  Conventionally, for surface decoration of building entrance doors and steel sheet material exterior members, the decorative sheet has been applied by directly applying a decorative pattern to the steel sheet member, or printed and uneven embossed on a polyvinyl chloride sheet. Has been used to bond steel sheet members with adhesives, etc., but it is difficult to express a design with unevenness by applying decorative patterns by painting, and decorative patterns using polyvinyl chloride decorative sheets Grants also tend to be shunned in recent years due to growing environmental awareness.

  On the other hand, in the field of decorative sheets in recent years, decorative sheets mainly made of polypropylene or acrylic resin that have the same design as polyvinyl chloride decorative sheets and have a low environmental impact have attracted attention. In particular, decorative sheets made of polypropylene resin as the main material tend to be less expensive to manufacture, including raw material costs than when acrylic resin is used, and there is a high market demand for polypropylene-based decorative sheets. .

  However, especially when a decorative sheet is bonded to a metal plate, the load applied to the decorative sheet during bending is greater than when using a decorative sheet, and a resin such as polypropylene or acrylic is used. Such a decorative sheet has a drawback that it tends to be whitened or cracked during bending. In particular, on the masked pattern layer side of the patterned base sheet for the purpose of protecting the masked pattern layer and improving wear resistance, scratch resistance, weather resistance, chemical resistance, etc., and improving design properties In a layer structure in which transparent resins are laminated, whitening and cracking are likely to occur when polypropylene or acrylic resin is used as the transparent resin.

  Bending of the metal decorative plate made by bonding the decorative sheet to the metal plate is usually performed by press molding, so it is bent after applying V-groove processing like a decorative plate using a wood or inorganic plate. Compared with the case where it processes, the load concerning the bending part of a decorative sheet at the time of a bending process is large, and a decorative sheet will be largely expanded locally by a bending part. And the load applied at the time of the folding is greater on the surface layer of the decorative sheet. In particular, when a highly elastic polypropylene is used for the polypropylene resin layer, the load applied at the time of bending tends to cause whitening or cracking in the polypropylene resin layer.

  In order to suppress this whitening and cracking, use a random type polypropylene for the polypropylene resin layer, or add a rubber component such as a single or copolymerized ethylene, propylene, or styrene material to make it elastic. The rate can be reduced and a certain degree of whitening and cracking suppression effect can be expected, but this is not the case for those with a larger bending load.

  In addition, the random type polypropylene often has a melting point in the range of about 130 to 150 ° C., which is lower than the range of about 150 to 170 ° C. that is the melting point of a general homo type polypropylene. For this reason, when a high-temperature heat load is applied, for example, when a decorative sheet is bonded to the steel sheet base material, the surface irregularity pattern of the random type polypropylene tends to change in shape.

Further, in a system in which a rubber component is added, the rubber components that can be selected are limited to those having a certain degree of compatibility with polypropylene. This is because if the compatibility of the rubber component with polypropylene is not increased to some extent, crazing occurs at the interface between polypropylene and rubber during bending, and as a result, whitening of the resin tends to occur. .
JP 2001-353828 A

  The present invention has been made in view of the drawbacks of the related art, and the problem is that it has wear resistance, scratch resistance, weather resistance, chemical resistance, etc., while having a conventional polypropylene decorative sheet. An object of the present invention is to easily provide a decorative sheet that has excellent flexibility, is less likely to be whitened or cracked during bending, and has excellent design.

  In order to solve the above problems, first, in the invention of claim 1, at least a base sheet made of a non-vinyl chloride material, a concealing pattern layer, and a single-layer or multi-layer transparent polypropylene resin layer are laminated in this order. In the decorative sheet, the resin used for at least one of the transparent polypropylene resin layers is a homopolypropylene having a crystallinity defined by a pentad fraction of 80% or less.

  According to a second aspect of the present invention, there is provided the decorative sheet according to the first aspect, wherein the transparent polypropylene resin layer has a melt flow rate defined by JIS-K6760 of 2 to 40 g / 10 min.

  According to the first aspect of the present invention, when a homopolypropylene having a crystallinity defined by a pentad fraction of 80% or less is used for a transparent polypropylene resin layer, a random type polypropylene is used or a rubber component is added. Compared to the system, whitening and cracking during bending are reduced. As a result, it is possible to perform a bending process that has been impossible until now.

  In addition, since it is a homo-type polypropylene, the melting point is higher than that of a random type polypropylene, and when a concavo-convex pattern is applied to the decorative sheet surface, the shape change of the concavo-convex pattern is less likely to occur compared to a random type polypropylene. Moreover, since it consists essentially of propylene, there is no concern about whitening due to the occurrence of crazes, as in the system with a rubber component added.

  According to the second aspect of the present invention, the melt flow rate (hereinafter referred to as MFR) defined by JIS-K6760 of the transparent polypropylene resin layer is set to 2 to 40 g / 10 min so that the makeup by the co-extrusion lamination method is used. It is suitable for film forming applications.

  Furthermore, by making the MFR of each resin layer at the time of co-extrusion as close as possible to the numerical values, the composition ratio in the width direction of the resin extruded from the T-die part when co-extrusing these becomes constant, As a result, the physical properties are equal in the width direction.

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the most basic structure of the present invention is that a transparent polypropylene resin layer 5 is formed on the surface of the base sheet 1 made of a non-vinyl chloride material having the mask pattern layer 2 on the mask pattern layer side. It is a laminated body formed by laminating.

  The base material sheet 1 is used as a base material of a decorative sheet. As a material, any material other than polyvinyl chloride may be selected in consideration of the use, price, and convenience of the decorative sheet. Polyolefin resins such as polypropylene and polyethylene are widely used. . Other than the above, for example, ethylene vinyl acetate copolymer, ethylene vinyl alcohol copolymer, polystyrene, ABS, polymethyl methacrylate, polymethyl acrylate, polybutyl acrylate, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl acetal , Polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, polyamide, nylon 6, nylon 66, paper, and the like may be used. If necessary, these materials may be combined to form a multilayer.

  The concealing pattern layer 2 is provided for imparting design properties such as a grain pattern, a stone pattern, a sand pattern, and an abstract pattern to the decorative sheet, or concealing the base material sheet by solid coloring. As a method for forming the concealing pattern layer 2, known methods such as gravure printing, offset printing, intaglio printing, screen printing, flexographic printing, silk printing, electrostatic printing, and ink jet printing are applied to the front surface or the back surface of the base sheet 1 or both. However, the present invention is not necessarily limited to this. Ink used is also known, that is, a colorant such as a dye or pigment, an extender is added to the vehicle, and a plasticizer, stabilizer, wax, grease, desiccant, curing agent, thickener, dispersant. In addition, a filler or the like may be arbitrarily added and sufficiently diluted with a solvent, a diluent or the like and stirred.

  When the T-die extrusion method is used as the manufacturing method of the base sheet 1, the base sheet 1 can be directly colored and extruded to form a masking pattern layer 2 to provide a masking effect. As a coloring method, a dry color method using a fine powdery colorant in which a pigment is treated with a dispersion aid or a surfactant, and a master batch pellet in which a resin and a high-concentration pigment are melt-mixed and pre-dispersed are prepared. However, there is a masterbatch method for dry blending with an ordinary resin not colored in an extrusion hopper, and there is no particular limitation. The types of pigments may be those usually used, but inorganic pigments such as titanium oxide, ultramarine blue, cadmium pigment, iron oxide and the like are particularly desirable in consideration of weather resistance and heat resistance. Also, organic pigments such as phthalocyanine pigments and quinacridone pigments can be used. The color and blending ratio of the pigment are arbitrarily determined in view of the degree of concealment and design properties, and are not particularly limited.

  In addition, as a method of applying the concealing pattern layer 2 to the base sheet 1, master batch pellets obtained by melting and mixing a high concentration pigment in a resin having different flow characteristics from the resin of the base sheet 1, or wood powder There is a method of forming the concealed pattern layer 2 on the base sheet 1 by adding glass powder and the like, and forming the base sheet 1 by extrusion film formation with the resin of the base sheet 1.

  Of course, it is possible to use a plurality of methods for forming the masking pattern layer 2 together. Moreover, as a manufacturing method of the base material sheet 1, the calendar method is generally used, but also in that case, the masking pattern layer 2 can be formed by using substantially the same method.

  The transparent polypropylene resin layer 5 is provided to improve the design properties of the decorative sheet, protect the masking pattern layer 2, and provide surface abrasion resistance, chemical resistance, scratch resistance, weather resistance, and the like. In the present invention, homopolypropylene having a crystallinity defined by a pentad fraction of 80% or less is used for at least one of the transparent polypropylene resin layers 5. This reduces the whitening and cracking at the time of bending compared to the case where random type polypropylene is used or a system with a rubber component added, and the melting point is higher than that of random type polypropylene. When applied, the shape change of the concavo-convex pattern is less likely to occur compared to the random type polypropylene. Moreover, since it consists essentially of propylene, there is an effect that there is no concern about whitening due to the occurrence of craze, as in the system to which a rubber component is added.

  As a method of laminating the transparent polypropylene resin layer 5 on the side where the concealing pattern layer 2 of the base sheet 1 is provided, a heat lamination method in which heat and pressure are applied, a dry lamination method in which an adhesive is used, and a wet lamination method are used. In addition to the extrusion lamination method in which a polypropylene resin is melt-extruded from a T-die onto a substrate sheet, there are methods such as a knee lamination method and a sand lamination method. Among these, the extrusion lamination method has the highest productivity, and therefore, extrusion lamination is preferable.

  Since it is used for the extrusion lamination, the MFR of the transparent polypropylene resin layer 5 is preferably in the range of 2 to 40 g / 10 min. If it is lower than 2 g / 10 min, the resin pressure at the time of extrusion tends to be high, so it has to be produced at a low take-off speed, and if it is higher than 40 g / 10 min, there will be uneven resin take-up when used for film forming. It tends to occur, and thickness unevenness in the flow direction of the decorative sheet tends to occur. If a resin with a close MFR cannot be selected for the convenience of material selection, adjustment is made by changing the resin temperature or changing the shape of the feed block part where the resin extruded from the screw joins.

In addition, since general polypropylene resins have poor adhesion to the same or different types of resins, in order to obtain a sufficient laminate strength by the extrusion lamination method, the structure as shown in FIG. The anchor coat layer 3 is applied on the base material sheet 1 and the transparent polypropylene layer 5 is coextruded through the acid-modified resin layer 4, and the ozone concentration of the acid-modified resin 4 is 10 to 50 g / m ³ and the ozone flow rate. A method of spraying ozone gas at a throughput of about 1 to 20 m ³ / hour is known. As the material used for the acid-modified resin layer 4, maleic acid-modified polyethylene resin, ethylene- (meth) acrylic acid copolymer resin, etc. are generally used, but when these resins are used, heat resistance, particularly 90 ° C. or more. Therefore, the laminate strength is significantly reduced. In particular, when a decorative sheet is bonded to a steel sheet substrate, heat of 120 to 250 ° C. may be applied to the adhesive to activate the adhesive, and temporarily, about 120 to 200 ° C. Heat may be applied to the decorative sheet. In such a case, it is preferable to employ a maleic acid-modified polypropylene resin having a high heat resistance to the acid-modified resin in order to maintain a sufficient laminate strength even when the decorative sheet is subjected to a high temperature.

  In addition to further improving the design properties of the decorative sheet, protecting the concealed pattern layer, exhibiting abrasion resistance, chemical resistance, scratch resistance, etc., and appropriately giving transparent gloss to the decorative sheet, transparent polypropylene A plurality of resin layers may be provided.

  In order to impart weather resistance to the decorative sheet, addition of an ultraviolet absorber, a light stabilizer and the like to the transparent polypropylene resin layer 5 is suitably performed. As the ultraviolet absorber, as long as it has a desired ultraviolet absorption effect and does not significantly affect the properties other than the weather resistance of the decorative sheet, there are no particular restrictions on its components and addition amount, for example, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5 Benzotriazole ultraviolet rays such as chlorobenzotriazole, 2- (3,5-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-5-t-octylphenyl) -benzotriazole Absorbents, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone and other benzophenone purple External line absorbers, triazine ultraviolet absorbers such as 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, cerium oxide, titanium oxide, etc. It is possible to add one or more of these inorganic ultraviolet absorbers in any combination.

  The light stabilizer is not particularly limited as long as it has a desired ultraviolet absorption effect and does not significantly affect the properties other than the weather resistance of the decorative sheet. For example, dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, poly [{6- (1,1,3,3-tetramethylbutyl) amino- 1,3,5-triazine-2,4diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) ) Imino}], N, N′-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4piperidyl) amino] — 6-chloro-1,3,5-triazine, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di-t-butyl-4-hydroxybenzyl)- 2-n-Butylmalonate Bis Hindered amines such as 1,2,2,6,6-pentamethyl-4-piperidyl) and tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate Light stabilizers, benzoate light stabilizers such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, bis- (2,2,6,6-tetra It is possible to use one or a combination of one or more of amino ether type light stabilizers such as methyl-1- (octyloxy) -4-piperidinyl) ester.

  In addition, a heat stabilizer, a flame retardant, an antiblocking agent, etc. are added as needed. The heat stabilizer is pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl)]-propionate, 2,4-bis- (n-octylthio) -6- (4- Hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl -2,4,6-tris (3,5-t-butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanur Hindered phenol antioxidants such as acids, 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol) Can be used in combination with one or more types of phenolic antioxidants such as tri) (phosphorus antioxidants typified by tris (2,4-di-t-butylphenyl) phosphite). It is.

  Examples of the flame retardant include inorganic compounds such as aluminum hydroxide, magnesium hydroxide, calcium carbonate, and magnesium carbonate, and phosphate ester flame retardants, but there are no particular limitations on the components. However, if it is a non-vinyl chloride sheet in consideration of the environment, it is necessary to consider the use of a halogen-based flame retardant.

  As the anti-blocking agent, an inorganic anti-blocking agent such as aluminum silicate, silicon oxide, hydrotalcite and calcium carbonate, an organic anti-blocking agent such as fatty acid amide, and the like are optionally added.

  In order to adjust the three-dimensional effect and the gloss of the surface, a concave pattern 5a may be provided as appropriate. As a method for applying the concave pattern 5a, a normal hot-pressure embossing method may be used, and the method is not limited at all. Further, when the T-die extrusion method (two-layer coextrusion film forming method of the acid-modified resin layer 4 and the polypropylene resin layer 5) is used as a method for forming the polypropylene resin layer 5, a chill roll for cooling and solidifying the molten resin is used. A concave pattern to be applied to the decorative sheet is provided on the surface with a pattern in which the irregularities are opposite to each other, and the extruded resin is embossed between a chill roll and a press roll to form a concave pattern 5a on the surface of the polypropylene resin layer 5. The method of applying is general.

  In addition, the surface protective layer 6 may be appropriately laminated. The material of the surface protective layer 6 is not particularly defined as long as it has sufficient adhesion to the transparent polypropylene layer in addition to the above physical properties, but a material using a urethane resin is more preferably used. It is done. Moreover, the said ultraviolet absorber, a light stabilizer, a heat stabilizer, a flame retardant, an antiblocking agent, etc. are added suitably as an additive.

  In addition, in order to improve the adhesion strength between the decorative sheet of the present invention and the wooden boards, inorganic boards, metal plates, etc., a primer layer 7 is provided on the back surface of the base sheet 1 as necessary. Also good. With respect to this primer layer, sufficient adhesion strength with the base material has been obtained, and the floating of the sheet between the base material sheet at the time of lamination and the wooden board, inorganic board, metal plate, etc. If it does not occur, it is not particularly specified, but it is preferable to use a polyurethane-based material.

  The decorative plate obtained by adhering the decorative sheet made in this way onto the metal plate is bent compared to the conventional one while maintaining the same level of chemical resistance and weather resistance as the conventional one. It is a decorative board with little whitening and cracking and excellent design.

A polypropylene sheet having a thickness of 70 μm was used as a base sheet, and a wood pattern was applied as a concealing pattern layer by gravure printing.
As a resin used for at least one of the transparent polypropylene resin layers, homopolypropylene (Idemitsu Kosan Co., Ltd .: Idemitsu TPO, MFR 4.5 g / 10 min) having a crystallinity defined by a pentad fraction of 70% is used. Used was prepared by adding 0.5 parts by weight of a hindered amine-based light stabilizer and 0.5 parts by weight of a benzotriazole-based UV absorber to the weathering formulation.
As the resin used for the acid-modified resin layer, a resin prepared by adding 30 parts by weight of ethylene propylene rubber to 70 parts by weight of maleic acid-modified random polypropylene resin obtained by modifying random polypropylene with an unsaturated carboxylic acid or an anhydride thereof was prepared.

The transparent homopolypropylene resin layer had a thickness of 80 μm and the acid-modified resin layer had a thickness of 10 μm, and was laminated with a base sheet using a co-extrusion lamination method. In this case, in order to increase the adhesion between the acid-modified resin and the ink layer, a main agent in which 5 parts by weight of epoxy is added to 100 parts by weight of urethane-modified polyester polyol, and hexamethylene diisocyanate and isophorone as isocyanate components. An anchor coating agent obtained by mixing a curing agent mixed with diisocyanate at a ratio of 1: 1 at a ratio of 4: 1 is 1 μm in thickness, between the acid-modified resin layer and the ink layer, on the surface of the ink layer. It applied using the gravure coat method. Further, immediately before the lamination, ozone gas was sprayed between the acid-modified resin and the anchor coat layer at an ozone concentration of 20 g / m ³ and an ozone flow rate of 3.0 m ³ / hour. Finally, on the outermost surface of this sheet, as a surface protective layer, a two-component curable urethane surface protective agent (Dainippon Ink Chemical Co., Ltd. “ UC Clear ") was applied to a thickness of about 9 μm to obtain a decorative sheet. This was bonded to a steel plate substrate using an olefin / steel plate adhesive (“Hybon” manufactured by Hitachi Chemical Polymer Co., Ltd.) to obtain a decorative plate.

[Comparative Example 1]
A decorative sheet was prepared in the same manner as in Example 1 except that homopolypropylene having a crystallinity of 95 (made by Idemitsu Kosan Co., Ltd .: Idemitsu PP) was used instead of the homopolypropylene in Example 1. Got.

[Comparative Example 2]
A decorative sheet was prepared in the same procedure as in Example 1 except that random polypropylene (Idemitsu Kosan Co., Ltd .: Idemitsu PP) having an ethylene content of 4 wt% was used instead of the homopolypropylene in Example 1. Got.

[Comparative Example 3]
Instead of homopolypropylene having a crystallinity of 70% defined by the pentad fraction, 80 parts by weight of homopolypropylene of Comparative Example 1 and 20 parts by weight of ethylene / propylene copolymer rubber (Mitsui Chemicals, Inc .: Toughmer) A decorative sheet was prepared in the same procedure as in Example 1 except that a resin obtained by polymer alloying was used to obtain a decorative plate.

<Performance comparison>
The bending workability and scratch resistance of the decorative plates of Example 1 and Comparative Examples 1 to 3 obtained as described above were evaluated. The results are shown in Tables 1 and 2 below.

  As can be seen from Table 1, the decorative board produced using the decorative sheet of the present invention is whitened or cracked in the bent portion even when subjected to 1R bending and 0t adhesion bending under 5 ° C and 25 ° C environments. Although it has not occurred, the decorative sheets shown in Comparative Examples 1 to 3 may be whitened or cracked depending on conditions, and as a result, the design feeling is greatly impaired.

  Further, as can be seen from Table 2, the surface hardness of the decorative sheet of the present invention is inferior in relative comparison with the decorative sheet shown in the comparative example, but the difference is slight and practically problematic. Don't be.

  Furthermore, in the present invention, since no vinyl chloride resin is used, there is also an advantage that it is a decorative sheet that is free from environmental problems.

It is explanatory drawing which shows the structure of the cross section of one Example of the decorative sheet in this invention. It is explanatory drawing which shows the structure of the cross section of one Example of the conventional decorative sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base material sheet 2 ... Concealment pattern layer 3 ... Anchor coat layer 4 ... Acid-modified resin layer 5 ... Transparent polypropylene resin layer 5a ... Depression pattern 6 ... Surface protection layer 7 ... Primer layer

Claims (2)

  In a decorative sheet in which a base sheet made of at least a non-vinyl chloride material, a concealing pattern layer, a single layer or multiple layers of a transparent polypropylene resin layer are laminated in this order, at least one of the transparent polypropylene resin layers A decorative sheet, wherein the resin used is a homopolypropylene having a crystallinity defined by a pentad fraction of 80% or less.   The decorative sheet according to claim 1, wherein the transparent polypropylene resin layer has a melt flow rate defined by JIS-K6760 of 2 to 40 g / 10 min.

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