JP2010158798A - Decorative sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative sheet which prevents the peeling strength from being lowered even after performing heat resistance test or the like and further prevents whitening of a processing part from occurring even when bending processing or pulling processing is applied. <P>SOLUTION: A transparent resin layer 5 coming into contact with an anchor coat layer 3 comprises a mixture of 40 to 90 parts weight of a polypropylene resin, 10 to 40 parts weight of an ethylene/α-olefin copolymer resin and 1 to 50 parts weight of a soft resin which is a copolymer resin obtained by copolymerizing propylene as a main raw material and at least one kind of ethylene and α-olefin, wherein a modulus of tensile elasticity prescribed by JIS-Z1702 satisfies 1 to 800 MPa. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a decorative sheet that is used as a decorative sheet by being bonded to the surface of, for example, wooden boards, inorganic boards, and metal plates with an adhesive.

  Conventionally, a vinyl chloride resin sheet has been most common as a decorative sheet used for the decorative board. In recent years, however, vinyl chloride resin has become a cause of the generation of hydrogen chloride gas and dioxin, which is a highly toxic substance, which causes acid rain during incineration, and also the problem of bleeding out of plasticizers added to vinyl chloride resin sheets From the viewpoint of environmental protection, various considerations are required for handling them. Under such circumstances, in recent years, a decorative sheet using a material other than vinyl chloride resin such as polypropylene, polyethylene, and acrylic has been demanded.

  Under these circumstances, decorative sheets using resins such as polyethylene, polypropylene, polyethylene terephthalate, ethylene vinyl alcohol, acrylic, and their copolymer resins as resins that replace vinyl chloride resins and their copolymer resins have been proposed and marketed. ing.

  Among them, makeup using polypropylene that is provided with reasonable flexibility, abrasion resistance, scratch resistance, heat resistance, chemical resistance, post-processability, transparency, etc. required for decorative sheets, and at low cost A large number of sheets have been proposed, and some of them have a single layer, but a laminate structure of two or more layers occupies most from the viewpoint of design.

  Up to now, the use of an ethylene-based resin in which an adhesive component is added to at least one of the two or more layers described above, suppresses stress concentration and improves the peel strength. Has been used (Patent Document 1). However, this decorative sheet has a problem that the peel strength after heat history is greatly reduced. In order to solve this problem, a specification using a polypropylene resin instead of an ethylene soft resin has been proposed and put into practical use (Patent Document 2).

However, if the resin is simply changed to a polypropylene-based resin, the stress relaxation ability is lost due to the high rigidity and the progress of crystallization of polypropylene during heating, so that sufficient peel strength may not be exhibited. In order to avoid these problems, measures such as the addition of an ethylene-based elastomer that is incompatible with polypropylene are taken as appropriate. However, even in this formulation, the decrease in peel strength after heat history is completely suppressed. I couldn't. In addition, because it is a mixture of a polypropylene resin and an incompatible resin, a minute void (dissociation) occurs at the interface between the incompatible resins when bending or pulling is performed. There were also problems such as the occurrence of whitening of the processed part depending on the conditions.
Japanese Patent No. 3185590 JP 2001-353828, etc.

  The present invention has been made in order to solve the above-mentioned problems, and the problem is that, after performing a heat resistance test or the like, the decrease in peel strength is eliminated, and further, bending processing and tensile processing are performed. It is an object of the present invention to provide a decorative sheet that does not cause whitening of a processed part even if it is applied.

  The present invention has been made in order to solve this problem. That is, the invention according to claim 1 includes two or more layers comprising a material composition mainly composed of an anchor coat layer and polypropylene on a base sheet. Transparent resin layer is a decorative sheet laminated at least in this order, and the transparent resin layer in contact with the anchor coat layer of the transparent resin layer is (a) 40 to 90 parts by weight of a polypropylene resin, (B) 10 to 40 parts by weight of an ethylene / α-olefin copolymer resin, (c) a copolymer resin obtained by copolymerizing at least one of ethylene and α-olefin using propylene as a main raw material. JIS Z 1702 1 to 50 parts by weight of a resin satisfying a tensile modulus of 1 to 800 MPa (provided that the total of (a) and (b) is 100 parts by weight). A decorative sheet according to claim.

  The invention described in claim 2 is characterized in that (a) is a random copolymer resin of propylene and at least one of ethylene or α-olefin excluding propylene. It is a decorative sheet of description.

  The invention according to claim 3 is defined as a crystal melting peak value when the temperature is raised from 0 ° C. to 300 ° C. at 10 ° C./min in the differential scanning calorimetry (DSC) of the random copolymer resin. The decorative sheet according to claim 2, wherein the crystal melting temperature is 100 ° C. or higher.

  The invention according to claim 4 is the decorative sheet according to any one of claims 1 to 3, wherein (c) is copolymerized using a metallocene catalyst. It is.

  Further, in the invention according to claim 5, (a) and (b) above are carried out by using an extrusion plastometer defined in JIS K6760 according to a measuring method defined in JIS K7210, at a melting temperature of 230 ° C. When the melt flow rate is measured under a load of 21.2 N, the melt viscosity ratio ((a) melt flow rate / (b) melt flow rate) is 3 to 40 times. It is a decorative sheet as described in any one of Claims 1-4.

  The invention described in claim 6 is characterized in that the two or more transparent resin layers are laminated by a heat-melt coextrusion laminating method using a T-die. It is a decorative sheet as described in one.

  According to the seventh aspect of the present invention, the transparent resin layer on the side in contact with the anchor coat layer is grafted with 2 parts by weight or less of unsaturated carboxylic acid or its anhydride relative to 100 parts by weight of the resin before modification. The decorative sheet according to any one of claims 1 to 6, wherein the decorative sheet is polymerized.

  The invention according to claim 8 is the decorative sheet according to claim 7, wherein the unsaturated carboxylic acid is maleic anhydride.

  According to the first aspect of the present invention, it is possible to suppress a decrease in peel strength due to thermal history. Since (a) and (b) are generally incompatible, they are in a continuous sea-island state immediately after being melt-kneaded with an extruder and then cooled and solidified, and the polypropylene resin due to the subsequent heat history Due to the progress of crystallization, dissociation (craze) occurs at the sea-island structure interface between (a) and (b), which causes a decrease in cohesive force and a decrease in peel strength. If (c) is added here, the effect of this resin will have the effect of suppressing the progress of crystallization in (a), thereby suppressing the occurrence of dissociation (crazing) due to thermal history. As a result, a decrease in peel strength after the thermal history is given is suppressed. In addition, the same mechanism can suppress whitening of the processed portion even when bending or pulling is performed.

  Each component ratio is (a) 40 to 90 parts by weight, (b) 10 to 40 parts by weight, (c) 1 to 50 parts by weight [(a) (b) is 100 parts by weight in total) and It is best to do. As for (c), when the amount of addition exceeds 30 parts by weight, the increase in the effect is not so large compared to the amount added. Therefore, a more preferable addition amount is 1 to 30 weights. When (a) exceeds 90 parts by weight and (b) is less than 10 parts by weight, the stress relaxation ability of the layer is not sufficiently exhibited. Moreover, when (b) exceeds 40 weight part, cohesion force will fall regardless of the presence or absence of (c). Further, (c) does not exhibit a sufficient effect at 1 part by weight or less.

  Examples of the α-olefin of (c) include monomers having about 3 to 20 carbon atoms, specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 4-methyl-1-pentene, and the like. In view of versatility and economy, propylene, 1-butene, 1-pentene and the like are preferable, and propylene and 1-butene are more preferable.

  In (c), it is also possible to use a homopolymer of propylene (so-called homopolypropylene) in which propylene is selected as the α-olefin, but in this case, in ordinary homopolypropylene, the tensile elastic modulus is 1 to 800 MPa. Since it is difficult to make it within the range, it is necessary to devise a method such as replacing part or all of the homopolypropylene with polypropylene having low regularity such as atactic polypropylene or syndiotactic polypropylene.

  Further, the invention according to claim 2 is effective in suppressing crystallization of polypropylene resin. In particular, when the blending amount of (c) is the same as that of (a), the crystallinity degree is better when (a) selects the random copolymer resin according to claim 2 than when selecting the propylene homopolymer resin. Tend to be lower.

  In order to obtain the same crystallinity, the amount of (c) blended can be reduced within the blending range of the present invention by selecting a random copolymer resin. This is particularly effective when (c) is very expensive or when the additive component or low molecular weight component of (c) adversely affects the performance of the decorative sheet. is there.

  In addition, according to the invention described in claim 3, it is possible to suppress a decrease in the delamination strength at the laminate interface particularly under a heat load, that is, in a high temperature environment. When the crystal melting temperature is 100 ° C. or lower, the cohesive strength of the resin under a high temperature environment is lowered, so that the interlayer strength when a constant load is applied under a high temperature environment is lowered. The interlaminar strength when a constant load is applied in a high temperature environment tends to be stronger and withstand higher temperatures as the melting point is higher. When considered, the crystal melting temperature of the required random copolymer resin should just be 100 degreeC or more. The upper limit of the crystal melting temperature is not particularly specified in terms of physical properties, but if it exceeds 300 ° C, the resin melting temperature at the time of molding must be set to exceed 300 ° C. However, care must be taken because the resin and additives may be decomposed.

  According to the invention described in claim 4, the resin (c) can be obtained relatively inexpensively as a resin having a narrow molecular weight distribution and high uniformity. This is because the metallocene catalyst is highly active as compared to the Ziegler-Natta catalyst generally used for conventional polypropylene polymerization. Because of this effect, the proportion of low molecular weight components in the copolymer resin can be kept low, which suppresses the stickiness of the surface layer and the decrease in adhesion of the surface protective layer, which is commonly used for olefin-based decorative sheets. I can do it. Further, by reducing the low molecular weight component, the effect of suppressing the decrease in transparency with time can be obtained.

  Further, according to the invention described in claim 5, the sea-island structure of the adhesive resin layer in contact with the anchor coat layer can be controlled within a certain range. When the difference in melt flow rate is 3 times or less, since the difference in melt viscosity is small, (b) is too finely dispersed in (a) and the stress relaxation ability is lowered. Further, when the difference in melt flow rate is 40 times or more, the islands of the sea-island structure are not sufficiently dispersed, which also leads to a decrease in stress relaxation ability.

  According to the invention described in claim 6, the transparent resin layers can be laminated at the same time without using an adhesive or the like, and the strength of the laminated interface becomes very strong. Furthermore, since lamination with the base sheet side can be performed at the same time, an efficient decorative sheet can be produced.

  Moreover, according to the invention of Claim 7 and Claim 8, a polar group can be introduce | transduced into a transparent resin layer, and it becomes possible to improve the adhesive strength of a base material sheet side and a transparent resin layer more. In addition, since polypropylene is a nonpolar resin, in order to develop strength by extrusion lamination, the extrusion temperature is increased to nearly 300 ° C and oxidation is performed using oxygen in the air, or ozone treatment is performed. However, since the functional group is previously introduced by carboxylic acid, a decorative sheet can be produced without limitation of the above conditions. In addition, the method of introducing polar groups by oxidation using oxygen in the air or ozone spraying depends on the speed of the laminate. Absent.

  The amount of graft polymerization of the unsaturated carboxylic acid or anhydride thereof is preferably 2 parts by weight or less with respect to 100 parts by weight of the resin before modification. The lower limit of the modification amount is not particularly defined, but when the modification amount is low, particularly when it is 0.1 parts by weight or less, there may be a case where sufficient laminate strength is not exhibited as it is. In such cases, polar groups can be introduced by taking measures such as ozone treatment, raising the extrusion temperature, and increasing the air gap (distance from the die to the position where the molten resin contacts the cooling roll). It is also possible to supplement the amount.

  In this case, however, if the conditions are excessive, care must be taken because the resin may be decomposed or yellowed, or the film-forming stability may be impaired. On the other hand, if it exceeds 2.0 parts by weight, the adhesion strength will not be so high even if the introduction amount is increased, conversely, the resin will be decomposed, which may cause a decrease in strength due to the embrittlement of the resin. In addition, problems such as yellowing may occur. In consideration of these problems, a more preferable introduction amount of the polar group is 1 part by weight or less, more preferably 0.4 part by weight or less.

  Examples of the unsaturated carboxylic acid include maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, acrylic acid, methacrylic acid, phthalic acid, and anhydrides thereof.

  Examples of the derivative of unsaturated carboxylic acid include acid halide compounds, amide compounds, imide compounds, acid anhydrides and ester compounds of unsaturated carboxylic acids as described above. Specific examples include maleyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, glycidyl maleate, and the like. Among these, unsaturated dicarboxylic acids or acid anhydrides thereof are preferable, and maleic acid or acid anhydrides thereof are particularly preferable in order to increase the laminate strength.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a schematic cross-sectional structure of a decorative sheet according to an embodiment of the present invention. In this decorative sheet, a pattern layer 2 and an anchor coat layer 3 are provided on a base sheet 1 made of a non-vinyl chloride resin material, and further an anchor coat made of a constituent material mainly composed of polypropylene. The transparent resin layer 4 and the transparent resin layer 5 in contact with the layers are laminated.
FIG. 2 shows a schematic cross-sectional structure of a decorative sheet according to another embodiment of the present invention.
Furthermore, in order to impart various performances such as design properties, scratch resistance, and weather resistance, a concave pattern 6, a filling ink 7 for the concave pattern portion, a surface protective layer 8, a primer coat layer 9, and the like are suitably provided.

  The transparent resin layer 5 is provided mainly to protect the pattern layer of the decorative sheet and to improve the design, and to exhibit scratch resistance, wear resistance, chemical resistance, etc. It consists of the constituent material. When importance is attached to scratch resistance, abrasion resistance, and resistance to thermal history, homopolypropylene obtained by polymerizing propylene alone is preferably used. Homopolypropylene has higher crystallinity and higher numerical values such as elastic modulus than random polypropylene and block polypropylene, and therefore performance such as scratch resistance and wear resistance is relatively good. Homopolypropylene has a particularly high melting point and softening point among polypropylenes, and particularly a homopolypropylene polymerized with a Ziegler-Natta catalyst has a melting point of 160 ° C. or higher, so that it has high resistance to thermal history and is preferably used.

  On the other hand, when emphasizing processability such as bending after bonding to the woody base material or steel plate of the decorative sheet of the present invention, and transparency, the constituent material of the transparent resin layer 5 is propylene. From 90 to 99 parts by weight, ethylene or an α-olefin having 4 to 20 carbon atoms (specifically, ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1 1 or more of nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 4-methyl-1-pentene, etc. 1 to 10 parts by weight of a random copolymer (however, the ratio when the total part by weight of both is 100), atactic polypropylene, or Shinji A method using a deliberately many homopolypropylene resin obtained by introducing a isotactic polypropylene component is suitably used. In general, homopolypropylene in which a large amount of random polypropylene, atactic polypropylene component, and syndiotactic polypropylene component is intentionally introduced can reduce the crystallinity of the molded product, thereby increasing flexibility and transparency. improves.

  You may make it improve the softness | flexibility and transparency of a transparent resin layer comprised by adding various rubber components in the constituent material of the above-mentioned transparent resin layer 5. FIG. Types of rubber components include isoprene rubber, butadiene rubber, butyl rubber, α-olefin copolymer rubber, chloroprene rubber, epichlorohydrin rubber, acrylic rubber, urethane rubber, silicone rubber, fluorine rubber, styrene butadiene rubber, chlorosulfonated polyethylene rubber, nitrile rubber Polysulfide rubber and the like can be mentioned, but depending on the type of material, it may be a factor that hinders transparency, so care must be taken. As for the rubber component, it is desirable to use a rubber component having as high a thermal stability as possible and a high glass transition point, melting point, Vicat softening point, and the like. In addition, it is necessary to use materials in consideration of the effects on scratch resistance, transparency, and the effects of precipitation (bleed out) of various additives described below.

  In order to improve the functionality of the decorative sheet, the transparent resin layer 5 includes a thermal stabilizer, a flame retardant, an ultraviolet absorber, a light stabilizer, a nucleating agent, an antiblocking agent, a catalyst supplement, and the like as necessary. It may be added as appropriate. Further, the thickness of the transparent resin layer 5 in the decorative sheet is preferably about 30 to 200 μm in view of various physical properties, production efficiency, economy, and the like, but is not necessarily limited to this range.

  The main role of the transparent resin layer 4 in contact with one anchor coat layer is to improve the adhesion between the transparent resin layer 5 and the base sheet 1 side. Therefore, the transparent resin layer 4 in contact with the anchor coat layer needs to have a performance to disperse / absorb the peeling stress when a stress acting on the base sheet 1 is peeled off. It is.

  In particular, when the transparent resin layer 5 and the transparent resin layer 4 in contact with the anchor coat layer are laminated by coextrusion, if the transparent resin layer 4 in contact with the anchor coat layer is also made of a polypropylene resin, the co-extrusion of the same kind of materials can be achieved. Since it becomes extrusion lamination, since those lamination strengths become strong, it is desirable.

  Even if the transparent resin layer 4 in contact with the anchor coat layer is made of a resin mainly composed of a material other than polypropylene resin, the crystallinity may be extremely lowered or an adhesive component such as a tackifier may be added. In some cases, the lamination strength of the coextrusion interface can be obtained by coextrusion with propylene resin. However, in many cases, heat resistance is difficult, and if there is a thermal history, it often leads to a significant decrease in strength after that. .

  Therefore, although the polypropylene resin is suitable for the transparent resin layer 4 in contact with the anchor coat layer, the polypropylene resin is in contact with the anchor coat layer by alloying an α-olefin copolymer elastomer resin that is incompatible with polypropylene. The stress relaxation ability of the transparent resin layer 4 increases.

  However, even in the above example, for example, a decrease in peel strength after a thermal history occurs. This is because the crystallization of the polypropylene resin proceeds due to the thermal history, but the α-olefin copolymer elastomer resin has little amorphous component, so that the crystallization hardly proceeds. Due to the effect of the difference, the sea-island interface is distorted and progresses to a crazing. Dissociation (craze) reduces the cohesive strength of the layer, resulting in a decrease in peel strength of the decorative sheet.

  Therefore, by using the resin composition as in the present invention, it becomes possible to suppress the distortion and detachment (crazing) at the sea-island interface after the heat history, and the peel strength of the decorative sheet after the heat history is improved. Moreover, since the occurrence of dissociation (crazing) at the sea-island interface also has the effect of facilitating whitening during the bending process, an effect of suppressing bending whitening can also be obtained.

  The thickness of the transparent resin layer 4 in contact with the anchor coat layer is preferably 4 to 30 μm. If it is 4 μm or less, the thickness is too thin to relieve stress. Moreover, even if the thickness is increased to 30 μm or more, no change is observed in the peel strength or whitening during bending.

  Examples of the method for laminating the transparent resin layer 4 and the transparent resin layer 5 in contact with the anchor coat layer and the method for laminating these laminates on the upper part of the base material sheet include a dry laminating method and a sand laminating method. Although a known method may be used, various advantages can be obtained by using a heat-melt coextrusion laminating method using a T die. For example, it is not necessary to provide an adhesive layer between the transparent resin layer 4 and the transparent resin layer 5 in contact with the anchor coat layer, and the transparent resin layer 4 and the transparent resin layer 5 in contact with the anchor coat layer are laminated. The product and the substrate sheet can be laminated at the same time, and efficient production becomes possible. Furthermore, when coextrusion laminating is performed, a pattern in which the unevenness is reversed from the design shape desired to be applied to the decorative sheet is provided in advance on the cooling roll, thereby simultaneously providing the concave pattern 6 on the decorative sheet surface. You will be able to do it.

  As a constituent material of the anchor coat layer 3, if a non-vinyl chloride resin material is used, the material is not limited, but a two-component curable urethane resin that forms a urethane bond by a reaction between a polyol and an isocyanate. Is preferably used. As the polyol component, polyester polyol or polyester polyurethane polyol is preferably used. Furthermore, as the isocyanate component, one containing at least one of hexamethylene diisocyanate or isophorone diisocyanate is preferably used. Further, as a method for forming the anchor coat layer 3, a gravure method (a gravure printing method or a gravure coating method) is preferably used, but is not necessarily limited thereto.

  In the decorative sheet of the present invention, the base sheet 1 includes polypropylene, polyethylene, ethylene vinyl acetate copolymer resin, ethylene vinyl alcohol copolymer resin, polystyrene, ABS, polymethyl methacrylate, polymethyl acrylate, polyacrylic acid. Sheets made of non-vinyl chloride resin materials such as butyl, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl acetal, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, polyamide, nylon 6, nylon 66, etc. It can be given as a specific example. Among these, considering recyclability, a base sheet made of a polyolefin material such as polypropylene or polyethylene is desirable. Furthermore, if the base sheet is made of a polypropylene material, most of the components of the decorative sheet are made of a polypropylene material. Therefore, although it is still desirable, it is not necessarily limited to this.

  Moreover, in the said resin which comprises the base material sheet 1, it is possible to add 1 type, or 2 or more types of additives, such as an inorganic pigment, antioxidant, a light stabilizer, and an antiblocking agent, in an appropriate quantity. It is.

  In the decorative sheet of the present invention, the base sheet 1 can be concealed. The reason for concealing is to prevent a base material such as a wooden board, an inorganic board, or a metal plate to be bonded from being visible from the surface of the decorative sheet. However, this is not the case when it is desired to make use of the texture of the base material.

  Application of concealability (concealment layer) and pattern layer 2 to the substrate sheet 1 is performed on the surface or the back surface of the substrate sheet 1 or both, gravure printing, intaglio printing, flexographic printing, silk printing, electrostatic printing, inkjet A known printing method such as printing is generally used, but is not necessarily limited thereto. In addition, the ink used at this time is also known, that is, a colorant such as a dye or pigment or an extender pigment is added to the vehicle, and further, a plasticizer, a stabilizer, a wax, a grease, a desiccant, a curing agent, a thickener. Ink formed by arbitrarily adding a dispersant, a filler and the like and kneading sufficiently with a solvent, a diluent and the like may be used.

  Further, a concealing layer and / or a pattern layer is formed on an arbitrary transfer base material sheet different from the base material sheet 1 for the decorative sheet by the above forming method, and the above-described thermal laminating method. Then, after laminating the substrate sheet 1 by the dry laminating method, the wet laminating method, the extrusion laminating method or the like, the transfer substrate sheet is peeled off, and the concealing layer and / or the pattern layer is used as a basis. A method of transferring onto the material sheet 1 can also be used.

  Further, when the T-die extrusion method is used as a method for producing the base sheet 1, a synthetic resin material for forming the film is directly colored with a concealing colorant such as a dye or a pigment and heated and melted. The substrate sheet 1 obtained by extrusion from the T die may be colored to impart concealability.

  In this case, the coloring method of the base sheet 1 in the T-die extrusion method includes a dry color method and a master batch method, but is not particularly limited. In the dry color method, a fine powdery colorant obtained by treating a pigment with a dispersion aid or a surfactant is directly mixed into an ordinary uncolored synthetic resin material for forming the base sheet 1. This is a method of coloring. On the other hand, in the master batch method, a master batch pellet in which a normal synthetic resin material that is not colored for forming the base sheet 1 and a high concentration pigment is melt-kneaded and pre-dispersed is prepared in advance. In the extrusion hopper, this master batch pellet is dry blended with a normal uncolored synthetic resin material for forming the base sheet 1 into a film.

  The types of pigments used for coloring may be those usually used, but inorganic pigments such as titanium oxide, ultramarine, cadmium pigment, iron oxide and the like are particularly desirable in consideration of heat resistance and weather resistance. Also, organic pigments such as phthalocyanine pigments and quinacridone pigments can be used. The pigment-to-resin ratio and hue are appropriately determined in view of the degree of concealment and design properties, and are not particularly limited.

  Moreover, as a method of applying the pattern layer 2 to the base sheet 1, there are a method of applying to the surface of the base sheet 1 and a method of applying to the base sheet 1 itself (in the layer of the base sheet 1). As a method for applying to the surface, the above printing method or transfer method can be used. As a method of applying to the base sheet 1 itself, master batch pellets, wood powder, glass powder, etc., in which a high-concentration pigment is melt-kneaded into a resin having different flow characteristics from the resin constituting the base sheet 1 and pre-dispersed A method of adding the above-mentioned synthetic resin material imparted with a concealing property for forming the base sheet 1, heating and melting, extruding, and forming a film may be mentioned. Thereby, it becomes possible to give the pattern by a masterbatch pellet, wood powder, glass powder etc. to the base material sheet 1 itself with concealment property. Of course, these methods of imparting color hiding properties and patterns to the substrate sheet 1 itself can be used in combination with the printing method and transfer method described above.

  Further, when the calendar method is used as a method for producing the concealable base sheet 1, the same method, that is, while the base sheet 1 is produced by the calender method, the base sheet 1 itself is simultaneously colored and concealed. The concealability and the pattern can be imparted to the base sheet 1 by a method of imparting a pattern, or a method using these methods in combination with the above-described printing method, transfer method and the like.

  In the decorative sheet of the present invention, in some cases, in order to obtain a touch feeling on the surface of the decorative sheet and a further design feeling, a concave pattern 6 is applied to the transparent resin layer 5 as shown in FIG. Accordingly, the filling ink 7 may be embedded in the recessed portion. As a measure for further enhancing the design feeling and various physical properties of the decorative sheet, the lamination of the surface protective layer 8 on the outermost layer of the decorative sheet is suitably used. Furthermore, in order to increase the adhesion of the decorative sheet to the woody / inorganic / metal-based substrate, lamination of the primer coat layer 9 on the back of the decorative sheet is also preferably used.

  The method for laminating the surface protective layer 8 may be any known technique and is not limited at all. Generally, the surface protective layer 8 is laminated with a thickness of about 3 to 20 μm using a gravure coating method. As the material system, an acrylic system, an ester system, a urethane system, or the like is preferably used. As the curing mode, an isocyanate curing type, an ultraviolet curing type, an electron beam curing type, or the like is generally used alone or in a hybrid manner. is there.

  A method for laminating the primer coat layer 9 may be a known method and is not limited at all. Generally, the primer coat layer 9 is laminated with a thickness of about 1 μm using a gravure coating method. As the material system, an isocyanate curable polyester material is preferably used. In addition, in order to prevent blocking when the decorative sheet is rolled (a phenomenon in which the stacked decorative sheets are too close to each other and difficult to peel off), the primer coat layer has a particle size of several μm such as silica. Addition of inorganic particulate materials is preferred.

  As base material sheet 1, 6 parts by weight of inorganic pigment, 10 parts by weight of inorganic filler, and 0.2% by weight of phenolic antioxidant with respect to 100 parts by weight of propylene / ethylene random copolymer resin with 4% ethylene content Part, 0.3 parts by weight of a hindered amine light stabilizer and 0.2 parts by weight of an antiblocking agent were used, and a sheet obtained by melt-extruding a resin was subjected to corona treatment on the surface, followed by gravure The pattern layer 2 was formed by applying a wood grain pattern using a pattern ink (“Lamister” manufactured by Toyo Ink Manufacturing Co., Ltd.) by a printing method. Furthermore, a two-component curable polyester urethane anchor coating agent (an anchor coating agent consisting of “Takelac” (main agent) and “Takenate” (curing agent) manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) is applied to the pattern layer 2 by a gravure printing method. Was applied at a thickness of about 1 μm and dried for 30 seconds in an environment of 40 ° C. to form an anchor coat layer 3.

  Next, on the upper surface of the anchor coat layer, 100 parts by weight of a soft polypropylene resin ("Prime TPO J5910" MFR = 8 manufactured by Prime Polymer Co., Ltd.) and 0.5 parts by weight of a hindered amine light stabilizer (Ciba Japan Co., Ltd.) "Kimasorb 2020") and 0.5 parts by weight of a benzotriazole UV absorber ("Tinubin 326" manufactured by Ciba Japan Co., Ltd.) and the composition shown in Table 1 The thickness ratio of the melt-kneaded material (becomes the transparent resin layer 4 on the side in contact with the anchor coat layer) is 65 μm for the thickness of the transparent resin layer 5 and 15 μm on the side of the transparent resin layer 4 in contact with the anchor coat layer. Thus, a transparent resin layer was laminated at a processing speed of 15 m / min so that a two-layer structure was formed by a T-die coextrusion laminating method at an extrusion temperature of 270 ° C. The decorative sheet of the present invention according to Examples 1 to 15 was obtained by the above method.

  As base material sheet 1, 6 parts by weight of inorganic pigment, 10 parts by weight of inorganic filler, 0.2 part by weight of phenolic antioxidant, hindered amine based on 100 parts by weight of random polypropylene resin with 4% ethylene content Using a sheet obtained by melt-extruding a resin obtained by adding 0.3 parts by weight of a light stabilizer and 0.2 parts by weight of an antiblocking agent, and applying corona treatment to the surface, the pattern is then printed by gravure printing. A wood grain pattern was applied using an ink for printing (“Lamister” manufactured by Toyo Ink Manufacturing Co., Ltd.) to form a pattern layer 2. Furthermore, an anchor coat agent composed of a two-component curable polyester urethane adhesive (“Takelac” (main agent) and “Takenate” (hardener) manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.)) is applied to the pattern layer 2 by a gravure printing method. The coating was applied at a thickness of about 4 μm and dried for 2 minutes in a 40 ° C. environment to form an adhesive layer.

On the other hand, soft polypropylene resin ("Prime TPO J5910" MFR = 8 manufactured by Prime Polymer Co., Ltd.) 100 parts by weight and 0.5 parts by weight of hindered amine light stabilizer ("Kimasorb 2020" manufactured by Ciba Japan Co., Ltd.) And benzotriazole-based UV absorber added with 0.5 parts by weight (“Tinubin 326” manufactured by Ciba Japan Co., Ltd.) and melted at the blending ratio shown in Table 1 What was kneaded (becomes the transparent resin layer 4 on the side in contact with the anchor coat layer) is such that the thickness ratio is 65 μm for the transparent resin layer 5 and 15 μm for the transparent resin layer 4 on the side in contact with the anchor coat layer. A film was formed by a T-die casting method at an extrusion temperature of 230 ° C. to prepare a sheet of a transparent resin layer.

  Then, the base sheet 1 on which the anchor coat layer is formed and the sheet of the transparent resin layer are bonded so that the anchor coat layer side and the transparent resin layer 4 side on the side in contact with the anchor coat layer are adjacent to each other, Aging was performed for 72 hours in the environment of the above to obtain a decorative sheet of the present invention according to Example 16.

<Comparative Examples 1-6>
A comparative example using the same method as in Examples 1 to 15 above, except that the resin constituting the transparent resin layer 4 on the side in contact with the anchor coat layer was changed to a melt kneaded mixture at the blending ratio shown in Table 2. A decorative sheet according to 1 to 6 was obtained.

The following four items were evaluated for each decorative sheet of Examples 1 to 16 and Comparative Examples 1 to 6 thus obtained.
<Comparison evaluation>
[1] Peel strength at 23 ° C. atmosphere.
[2] Peel strength after heating in an oven at 90 ° C. for 72 hours.
[3] The surface protective layer 8 (made by DIC Corporation: “UC Clear”) was used, and this was gravure-coated on the surface of the transparent resin layer 5 with a thickness of 6 μm, and aged for 72 hours in a 60 ° C. environment. After that, using a weathering accelerated test [weathering tester (Daipla Intes: die plastic metal weather), illuminance 70 mW / cm ² (wavelength 300 to 400 nm), black panel temperature 53 ° C., 20 hours irradiation and 4 hours Peel strength after 96 hours after repeating the condensation (30 seconds each before and after condensation).
[4] Bending process when 1R bending is performed in an environment of 5 ° C. after bonding the decorative sheets of Examples and Comparative Examples on a 0.5 mm thick steel sheet with an adhesive of 10 μm thickness The degree of whitening of the part.

  In addition, at the time of bonding on a steel plate, in order to activate the adhesive and improve the adhesion between the adhesive and the decorative sheet, the steel plate coated with the adhesive was heated in an oven at 200 ° C. for 3 minutes. Then, before the heat of the steel plate was cooled, a laminator was used to bond the decorative sheet, and immediately after that, the plate was cooled with cold water.

  The evaluation results by the above test methods are shown in Table 3 (results of decorative sheets of examples) and Table 4 (results of decorative sheets of comparative examples).

  Hereinafter, discussion on results and effects of the decorative sheet of the present invention will be described.

  The decorative sheets of Examples 1 to 16, which correspond to the examples according to the present invention, are heated at 90 ° C. for 72 hours or 96 hours by metal weather while securing a laminate strength of 20 N / 25 mm or more at 23 ° C. atmosphere. Even after the weather resistance acceleration test is performed, the laminate strength is secured to 15 N / 25 mm or more, and the strength reduction against these loads is not large. Further, even in the bending process after being bonded to the steel plate base material, whitening is hardly observed, which is favorable. As described above, the decorative sheet of the present invention is characterized in that the decorative sheet has not only a small decrease in peel strength at the laminate interface with respect to loads such as heat and ultraviolet rays, but also a good post-processing property after the manufacture of the decorative sheet. Have both. On the other hand, the decorative sheets of Comparative Examples 1 to 6 cannot hold various physical properties at a high dimension like the decorative sheets corresponding to the examples according to the present invention.

  Subsequently, the performance comparison among the decorative sheets of Examples 1 to 16 will be described.

  When Examples 1 and 2 are compared, the decorative sheet of Example 1 has somewhat higher heat resistance, but the weather resistance is slightly reduced. This is considered to be the effect of using a propylene homopolymerized polypropylene resin having high heat resistance but poor flexibility in the cosmetic sheath of Example 1. However, regarding the heat resistance performance, the difference between the first and second embodiments is a comparison in a very high intensity value region. Therefore, when emphasizing the effect of raising the weather resistance performance, it is random as in the second embodiment. It is even better to use a copolymer resin.

  Examples 2 to 6 are the results of fine adjustment of the blending ratio of each resin within the scope of the present invention. If it is within the scope of the present invention, various physical property values are at a high level. However, if the blending amount of (b) is small, the laminate strength in a 23 ° C. environment or after 90 ° C. heating is a relative comparison. While a high value can be obtained, the laminate strength after the weather resistance test tends to be low by relative comparison. When the blending amount of (b) is large, the tendency is opposite to this.

  As in Example 7, when a resin having a low melting point is selected for (a), the laminate strength after heating at 90 ° C. tends to be lower than that in Example 2. This is considered to be due to the fact that a high-temperature heat history is applied in the state where a low melting point resin is used.

  As in Example 8, when polymerization was performed using a Ziegler-Natta catalyst as (c), the laminate strength value after the weather resistance test was different from that in Example 2 polymerized with a metallocene catalyst. Appears. This is because, when polymerized with a Ziegler-Natta catalyst that is less active compared to the metallocene catalyst, the low molecular weight component is present in a high proportion, and this low molecular weight component is collected in the vicinity of the laminate interface by the weather resistance test. It can be thought that it was because of lowering.

  As in Examples 9 to 10 and Example 2, the physical property values also change by changing the melt flow rate ratio between (a) and (b) within the scope of the present invention. When the melt flow rate ratio is reduced, the cohesive strength of the resin B layer is reduced, causing cohesive failure from the 23 ° C. environment, and the measured laminate strength tends to be relatively low. When the melt flow rate ratio is increased, the cohesive force of the resin B layer is increased, and the laminate strength measurement value in a 23 ° C. environment is also increased. However, when the melt follow rate ratio is excessively increased, the anchor coat layer and Since the ability to absorb the peeling stress of the transparent resin layer 4 on the contact side is lowered, the laminate strength value after the weather resistance test tends to be lowered. When the melt flow rate ratio is set as described in claim 5, a decorative sheet having the most balanced physical properties can be obtained.

  From the results of Examples 11 to 15 and Example 2, when maleic acid graft modification was not performed, it was necessary to further devise for introducing a polar group such as extrusion temperature increase, and excessively. It can be seen that maleic acid modification leads to a decrease in laminate strength.

  Finally, the comparison between Example 16 and Example 2 shows that there is no significant difference in physical properties between the dry lamination method and the extrusion lamination method. However, as described in the examples, the production of a decorative sheet by the dry laminating method requires film forming and laminating in separate steps, whereas in the extrusion laminating method, film forming and laminating are performed. Since one process can be omitted, there is an advantage that productivity is increased.

Since the decorative sheet of the present invention does not use any vinyl chloride resin, there is no concern about environmental problems, and since the main material is a polypropylene resin with a large amount of distribution in the market, it is inexpensive and stable in supply. Although it is high, it has sufficient values for heat-resistant adhesion and weather-resistant adhesion. Moreover, even if bending is performed, design changes such as whitening of the processed portion hardly occur. Therefore, it is possible to provide a highly practical decorative sheet that is also excellent in design.

It is explanatory drawing which shows the general | schematic cross-section which concerns on one Embodiment of the decorative sheet of this invention. It is explanatory drawing which shows the schematic cross-section which concerns on other embodiment of the decorative sheet of this invention.

DESCRIPTION OF SYMBOLS 1 ... Base material sheet 2 ... Pattern layer 3 ... Anchor coat layer 4 ... Transparent resin layer in contact with anchor coat layer 5 ... Transparent resin layer 6 ... Recessed pattern 7 ... Filling ink 8 ... Surface protective layer 9 ... Primer coat layer

Claims (8)

A decorative sheet in which an anchor coat layer and two or more transparent resin layers composed mainly of polypropylene are laminated in this order on a base material sheet, A transparent resin layer in contact with the anchor coat layer of
(A) 40 to 90 parts by weight of polypropylene resin,
(B) 10 to 40 parts by weight of ethylene / α-olefin copolymer resin,
(C) A resin 1 which is a copolymer resin obtained by copolymerizing propylene as a main raw material and at least one of ethylene and α-olefin, and satisfying a tensile elastic modulus defined by JIS Z 1702 of 1 to 800 MPa. -50 parts by weight (however, the total of (a) and (b) is 100 parts by weight)
A decorative sheet characterized by comprising a mixture of these.   The decorative sheet according to claim 1, wherein (a) is a random copolymer resin of propylene and at least one of ethylene or an α-olefin excluding propylene.   In the differential scanning calorimetry (DSC) of the random copolymer resin, the crystal melting temperature defined as the crystal melting peak value when the temperature is raised from 0 ° C. to 300 ° C. at 10 ° C. per minute is 100 ° C. or higher. The decorative sheet according to claim 2, wherein:   The decorative sheet according to any one of claims 1 to 3, wherein (c) is copolymerized using a metallocene catalyst.   The above (a) and (b) are melt flowed under conditions of a melting temperature of 230 ° C. and a load of 21.2 N in accordance with a measurement method defined in JIS K7210 using an extrusion plastometer defined in JIS K6760. The melt viscosity ratio ((a) melt flow rate / (b) melt flow rate) is 3 times or more and 40 times or less when the rate is measured. The decorative sheet according to one.   The decorative sheet according to any one of claims 1 to 5, wherein the two or more transparent resin layers are laminated by a hot melt coextrusion laminating method using a T die.   The transparent resin layer in contact with the anchor coat layer is graft-polymerized with 2 parts by weight or less of an unsaturated carboxylic acid or its anhydride with respect to 100 parts by weight of the resin before modification. Item 7. The decorative sheet according to any one of Items 1 to 6. The decorative sheet according to claim 7, wherein the unsaturated carboxylic acid is maleic anhydride.

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