JP2019042958A - Decorative sheet and decorative plate - Google Patents

Abstract

To provide an olefin-based decorative sheet and decorative plate having noncombustibility which cause no deterioration in design by film-thinning without using a halogen-based flame retardant and do not reduce mechanical properties or productivity even if the addition amount of an inorganic material is increased.SOLUTION: There is provided a decorative sheet 10 which has at least an inorganic substance-containing resin layer 1, a pattern layer 2, a polyolefin-based transparent resin layer 3 and a surface protective layer 4, wherein the inorganic substance-containing resin layer 1 has a thickness within the range of 30 to 110 μm, is a mixture obtained by blending 60 to 85 mass% of an inorganic substance, 1 to 39 mass% of a hydrocarbon-based resin and 0.01 to 1 mass% of a dispersant and is stretched by 1.1 to 5.0 times in the film forming direction. Further, there is provided a decorative sheet in which the inorganic substance-containing resin layer 1 is stretched by 1.1 to 1.5 times in the direction vertical to the film forming direction. There is provided a method in which the inorganic substance contains calcium carbonate as a main raw material and contains one more selected from a pigment, titanium dioxide talc, mica, talc and silica as an auxiliary raw material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a decorative sheet that is used as a decorative plate by being bonded to the surface of various decorative substrates such as wooden boards, inorganic boards, and metal plates with an adhesive, and particularly relates to a decorative sheet mainly using a polyolefin resin. .

  Conventionally, decorative sheets are pasted together to impart design properties to various base materials, and at first, those made of paper or polyvinyl chloride resin were mainly produced and used. However, with the recent increase in interest in environmental problems, decorative sheets made of polyvinyl chloride resin have been avoided, and in place of them, those based on polyolefin resins have been used favorably.

  Various problems have been pointed out at the time of switching from a polyvinyl chloride resin to a polyolefin resin for a decorative sheet, but many of them have been solved by the maturity of technology. However, it has been difficult to impart the same performance as that of a polyvinyl chloride resin decorative sheet with a polyolefin resin decorative sheet in the part related to the non-combustible performance. Therefore, methods such as adding a flame retardant to a polyolefin-based resin, reducing the amount of resin used, such as thinning or adding inorganic components, have been studied (for example, Reference 1).

However, the addition of a flame retardant is a highly effective bromine-based halogen substance, and there is a concern that it may conflict with the EU (European Union) RoHS directive and REACH regulations.
Moreover, there is a problem that the thinning leads to deterioration of the mechanical properties and design properties of the sheet. If the amount of the inorganic component added is increased, the mechanical properties deteriorate or the production becomes unstable. If the former, the blending amount is suppressed, if the latter, the blending amount is suppressed, or the production rate is slowed. It was necessary to do or to combine both. However, if such a method is adopted, the productivity will be significantly reduced.

Japanese Patent No. 5699703

  In view of the above problems, the object of the present invention is to eliminate the limitations that occur in conventional olefin-based decorative sheets, that is, without using halogen-based flame retardants, without causing design deterioration due to thinning, and inorganic An object of the present invention is to provide an olefinic decorative sheet and decorative plate having non-flammability, which do not deteriorate mechanical properties and productivity even when the amount of material added is increased.

The present invention solves this problem, that is, the invention according to claim 1 is
In a decorative sheet having at least an inorganic substance-containing resin layer, a pattern layer, a polyolefin-based transparent resin layer, and a surface protective layer, the inorganic substance-containing resin layer is in the range of 30 to 110 μm in thickness, and the inorganic substance is 60 to 85% by mass. , 1 to 39% by weight of a hydrocarbon-based resin and 0.01 to 1% by weight of a dispersant, and is characterized by being stretched 1.1 to 5.0 times in the film forming direction. It is a decorative sheet.

The invention according to claim 2 is that the inorganic substance-containing resin layer according to claim 1 is further stretched 1.1 to 1.5 times by stretching in a direction perpendicular to the film forming direction. The decorative sheet according to claim 1, characterized in that it is a decorative sheet.

  The invention according to claim 3 is the decorative sheet according to claim 1 or 2, wherein the inorganic substance is mainly made of calcium carbonate.

  The invention according to claim 4 is that the inorganic substance contains calcium carbonate as a main raw material, and contains at least one selected from the group consisting of pigment, titanium dioxide, talc, mica, and silica as an auxiliary raw material. The decorative sheet according to any one of claims 1 to 3, characterized in that it is a decorative sheet.

  The invention according to claim 5 is the decorative sheet according to any one of claims 1 to 4, wherein a receiving layer is further provided between the inorganic substance-containing resin layer and the pattern layer. is there.

  The invention according to claim 6 is a decorative board obtained by bonding the decorative sheet according to any one of claims 1 to 5 to a non-combustible board.

  According to the first aspect of the present invention, a decorative sheet excellent in mechanical properties and productivity can be obtained while containing a large amount of inorganic components. By performing the stretching process on the inorganic-containing resin layer, for example, the speed immediately after film formation is slow, and even if the film is thick, the sheet is stretched by subsequent stretching. The speed is increased by the draw ratio, and the thickness is also reduced by the draw ratio. Further, by stretching, mechanical properties are improved because crystallization of the resin is promoted. Furthermore, since minute cracks (craze) generated at the interface between the resin and the inorganic material during stretching cause irregular reflection of light, concealment can be imparted by becoming opaque.

  Here, the stretching ratio is a value in which the length of the sheet before the stretching process is represented by 1, and the length of the sheet after the stretching process is expressed by a magnification. The draw ratio is preferably in the range of 1.1 to 5.0 times, more preferably in the range of 1.5 to 3.0 times, and still more preferably in the range of 1.8 to 2.5 times. Is within. By stretching the film by 1.1 times or more, the above-mentioned effect is effectively exhibited, and by making it 5.0 times or less, a sheet that does not cause film breakage or rough surface during stretching can be obtained.

  The thickness after stretching is preferably in the range of 30 to 110 μm. By setting the thickness to 30 μm or more, practically sufficient mechanical properties can be maintained, and necessary concealing properties can be obtained. By setting the thickness to 110 μm or less, the resin content can be reduced to a sufficient amount as a sheet for a noncombustible decorative board. On the other hand, when the thickness is 110 μm or more, the amount of resin used is not different from the amount of resin in the conventional coloring sheet for decorative sheet, and the cost increases and the industrial value decreases.

  According to the second aspect of the present invention, the tearability can be improved. A so-called uniaxially stretched sheet stretched only at the peripheral speed ratio of the roll has a strong mechanical strength against tension and tearing in the stretching direction, but against tensile and tearing loads in a direction perpendicular to the stretching direction. It has the property of being easy to tear. In order to compensate for this, stretching in the transverse direction is preferred. Stretching in the transverse direction is mainly aimed at imparting a minimum mechanical strength, so it is not necessary to increase the draw ratio so much, and a range of 1.1 to 1.5 times is preferable. When the draw ratio exceeds 1.1 times, an effect of improving mechanical properties is seen, and when the draw ratio is 1.5 times or less, thermal shrinkage in the subsequent process can be suppressed.

  Specific examples of the heat shrinkage in the post-process include a drying process after printing, a lamination process of the polyolefin-based transparent resin layer, and a curing process after completion of the lamination. In particular, when the lamination of the polyolefin-based transparent resin layer is to be carried out by an extrusion lamination method, heat shrinkage tends to occur remarkably, but if the draw ratio is in the range of 1.1 to 1.5 times, The problem can be prevented.

According to the third aspect of the present invention, it is possible to obtain an inorganic-containing resin layer that is economically inexpensive and has a high proportion of inorganic components without greatly affecting resin molding. The reason is that by using calcium carbonate as the main raw material, the degree of freedom of shape can be increased in the pulverization step, and the particle size, surface smoothness, and spherical shape of the particles can be improved.
The average particle size is preferably 50% average (D50) of the particle size distribution in the range of 0.5 to 10 μm, more preferably in the range of 1.0 to 5 μm, more preferably 2.0 to 5 μm. It is more desirable to be within the range. If it is 0.5 μm or more, it is difficult to cause agglomeration at a level that affects the quality, and if it is 10 μm or less, the calcium carbonate with a large particle size that is generated stochastically clogs the mesh or damages the inside of the extruder. The risk of doing it can be avoided. The higher the surface smoothness and the higher the sphericity of the grains (close to the sphere), the higher the content.

  According to the invention of the fourth aspect, the present invention can give further added value. By adding a pigment, the design of a decorative sheet can be improved, and by adding titanium dioxide, the concealability can be further improved and the effect of improving whiteness can be exhibited at the same time. By adding talc, mica (mica), etc., the mechanical strength of the sheet can be further improved.

  According to the invention of the fifth aspect, the present invention can improve the adhesion of the pattern layer. The stretched sheet may deteriorate the adhesion of the pattern layer provided by printing or the like due to the orientation, but it can play a role of complementing the adhesion of the pattern layer by providing a receiving layer. I can do things. The material of the receiving layer is not particularly limited, but for example, polyolefin resins such as polyethylene and polypropylene are used. Further, for the purpose of improving the adhesion of the printing ink and suppressing the bleeding of the ink after printing, it is also preferable to add calcium carbonate or silica to these resins.

  According to the present invention, a polyolefin-based decorative board comprising a decorative sheet containing a large amount of an inorganic substance can be obtained. If a non-combustible plate is used for the base material, even if a non-combustible performance is not obtained when a conventional decorative sheet having the same thickness is applied, the inorganic content is not applied to the decorative sheet. Since the organic content can be reduced as much as is contained, nonflammability performance is exhibited.

It is explanatory drawing which shows the structure of the cross section of the 1st Example of the decorative sheet of this invention. It is explanatory drawing which shows the structure of the cross section of the 2nd Example of the decorative sheet of this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows a cross-sectional structure of the first embodiment of the decorative sheet of the present invention. The decorative sheet 10 of the present invention is composed of a laminate in which a pattern layer 2, a polyolefin-based transparent resin layer 3, and a surface protective layer 4 are laminated in this order on an inorganic substance-containing resin layer 1.

  Moreover, FIG. 2 shows the structure of the cross section of the 2nd Example of the decorative sheet of this invention. The decorative board 20 of the present invention is obtained by laminating an inorganic substance-containing resin layer 1 on a non-combustible board 12 as a base material, and further forming a receiving layer 13, a pattern layer 2, a polyolefin-based transparent resin layer 3, and a surface protective layer 4 in this order. It consists of the laminated body laminated | stacked.

The polyolefin-based resin used for the polyolefin-based transparent resin layer 3 is not particularly limited. Specifically, in addition to polypropylene, polyethylene, polybutene and the like, α-olefin (for example, propylene, 1-butene, 1- Pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1- Octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-mes 1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.), homopolymerized or copolymerized with two or more kinds, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol Copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, ethylene / butyl methacrylate copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer A copolymer obtained by copolymerizing ethylene or α-olefin and other monomers, such as a coalescence, can be used.

  Although it does not specifically limit as an inorganic substance used for the inorganic substance containing resin layer 1, For example, a calcium carbonate, a titanium oxide, a talc, a mica (mica), a silica, various pigments etc. can be used conveniently.

  The pattern layer 2 is provided to give the decorative sheet a design such as a wood grain pattern, a stone pattern, a sand pattern, or an abstract pattern, or to conceal the base material sheet by solid coloring. As a method for forming the pattern layer 2, known printing such as gravure printing, offset printing, intaglio printing, screen printing, flexographic printing, silk printing, electrostatic printing, and ink jet printing is performed on the front surface or the back surface of the base material sheet or both. The technique is generally used, but is not necessarily limited thereto.

  Further, the ink used for the pattern layer 2 is also a known ink, that is, a coloring agent such as a dye or a pigment, an extender is added to the vehicle, and further, a plasticizer, a radical scavenger, a wax, a grease, a desiccant, a curing agent, A thickener, a dispersant, a filler and the like may be arbitrarily added, and the mixture may be sufficiently diluted and stirred with a solvent, a diluent or the like.

  As the surface protective layer 4, a method of providing a resin layer such as an ultraviolet curable type, an isocyanate curable type, or an electron beam curable type is generally used. Otherwise, a method of laminating a thermoplastic resin, or a surface protective layer in the first place. There is also a method of not providing the. There is a method in which one type is selected from these, or in some cases, two or more types are used in a hybrid manner.

  The material of the surface protective layer 4 is preferably an acrylic material, and in view of weather resistance, a methacrylate type is desirable. Among them, a resin based on methyl methacrylate is particularly desirable. The thickness of the surface protective layer is not particularly specified, but is preferably about 3 to 20 μm. If it is 3 μm or less, it is difficult to impart sufficient scratch resistance and weather resistance, and if it is 20 μm or more, the effect of improving scratch resistance by increasing the thickness is hardly seen, but it is not preferable in terms of handling and economy.

  In addition, a primer layer (not shown) may be provided between the decorative sheet and the incombustible plate, if necessary, in order to improve the adhesion strength between the decorative sheet and the incombustible plate in the decorative plate.

Next, examples of the decorative sheet and decorative plate of the present invention will be shown.
Hereinafter, effects will be described on the basis of preliminary experimental examples, examples and comparative examples.

(Preliminary experiment example)
As a preliminary experiment, a sheet used for the inorganic substance-containing resin layer 1 was produced as follows.
In this example, calcium carbonate is used as the main component of the inorganic substance.
29.7 parts by mass of high-density polyethylene resin (Hi-Zex 550BR, melt mass flow rate = 0.27 g / 10 min, manufactured by Prime Polymer Co., Ltd.) and calcium carbonate (Softon 1000) having an average particle diameter (D50) of 2.2 μm 70 parts by mass, manufactured by Bihoku Flour Industry Co., Ltd.), 0.3 parts by mass of 12 hydroxy magnesium stearate (MS-6, manufactured by Nitto Kasei Kogyo Co., Ltd.) as a dispersant was used, and a Banbury mixer was used. After kneading, pellets were prepared by a hot cut method using a pelletizer.

  The prepared pellets were formed into a sheet using a T-die type single screw extruder. The conditions were a set temperature of 200 ° C., cooling was a roll nip method, a lip gap of 1.0 mm, an air gap of 110 mm, a line speed of 10 m / min, and a film forming thickness of 70 μm. However, the film was cut after the molten resin T-die was discharged, and stable film formation was not possible.

  When the thickness of the film was raised to 100 μm again, the film was not cut after the T-die was discharged, and the film thickness was increased to 200 μm, so that the film could be formed with a thickness accuracy within 10 μm.

(Examples 1-8)
The sheet used for the inorganic substance-containing resin layer 1 prepared in the preliminary experiment example was stretched using the peripheral speed ratio of the roll while being heated at 90 ° C., and the thickness was reduced to 70 μm (stretching ratio: 2.9 times). An axially stretched sheet A-1 was prepared. Furthermore, the biaxially stretched sheet B-1 was created by chucking the sheet edge and stretching the film in the transverse direction at 95 ° C. to reduce the thickness to 60 μm (stretch ratio 1.2 times). .
On both surfaces of the prepared sheet A-1 and sheet B-1, a solution in which 30% of silica is dispersed in an isocyanate-curable polyester urethane primer is applied in an amount of 2 g / m ² to form a receiving layer 13. A uniaxially stretched sheet A-2 and a biaxially stretched sheet B-2 were prepared.

  Preliminary experiment, except that 5 parts by weight of 70 parts by weight of calcium carbonate (Softon 1000, manufactured by Bihoku Flour Industry Co., Ltd.) was replaced with titanium dioxide (Taipeku CR-63, manufactured by Ishihara Sangyo Co., Ltd.) And using the same method as the biaxial stretching of the examples, the biaxially stretched sheet C-1 containing titanium oxide, and the biaxially stretched sheet C-2 in which the receiving layer 13 was formed by applying the primer solution on both sides thereof It was created.

  Calcium carbonate (Softon 1000, manufactured by Bihoku Flour & Chemical Co., Ltd.) was replaced by talc (P-8, manufactured by Nippon Talc Co., Ltd.) in 5 parts by weight of 70 parts by mass. Using the same method as the biaxial stretching of the example, a biaxially stretched sheet D-1 containing talc and a biaxially stretched sheet D-2 in which the above primer solution was applied to both sides to form a receiving layer 13 were prepared. .

Addition of an isocyanate curing agent to gravure ink (XS-756; manufactured by DIC Graphics Co., Ltd.), prepare a coating liquid whose viscosity is adjusted with a methyl ethyl ketone solvent, and prepare inorganic substance-containing resin sheets A1 to D1 as described above. And the pattern layer 2 was printed on the single side | surface of A2-D2 using the gravure printing method.
On the opposite side of the inorganic material-containing resin sheet, a gravure ink with a pigment component removed is prepared, and an appropriate amount of silica is added using a gravure coater, and the coating amount is 1 g / m ² (dry). I painted it with my aim. This is to improve the adhesion with the adhesive when a non-combustible plate described later is bonded.

After curing, an isocyanate curing agent is added as an anchor coating agent (Takelac_A3210: manufactured by Mitsui Chemicals) to the side on which the pattern layer 2 is provided on the inorganic substance-containing resin sheet, and the solid content is 25% with an ethyl acetate solvent. After coating with a bar coater with the aim of coating amount of 1 g / m ² (dry), resin 1 and T die 2 type 2 layer coextrusion laminator were used in advance as shown in Table 1 below. Resin 2 was blended and kneaded polypropylene resin was coextruded and laminated. Here, the resin 1 uses a modified polypropylene resin, and the resin 2 contains a transparent polypropylene resin as a main component and a mixture of a small amount of a benzotriazole ultraviolet absorber and a hindered amine radical accelerator.

Thereafter, corona treatment is performed, and as the surface protective layer 4, a hexamethylene diisocyanate curing agent and methyl ethyl ketone as a diluent solvent are appropriately added to an acrylate coating agent (UC Clear_W480E: manufactured by DIC Graphics Co., Ltd.). Was applied so as to be within the range of 6 ± 1 g / m ² (dry). Thereafter, curing was performed in an oven at 40 ° C. for 3 days. Thus, as shown in Table 2 below, the polyolefin-based decorative sheets of Examples 1 to 8 were produced.

(Comparative Example 1)
Instead of the sheets A2 to D2 created in Examples 5 to 8 above, using a colored sheet (OW, inorganic content 20% by mass, thickness 60 μm, manufactured by Riken Technos Co., Ltd.) produced by a T-die extruder, Otherwise, the decorative sheet of Comparative Example 1 was produced in the same manner as in the Examples.

<Performance evaluation>
(Exothermic test)
The decorative sheets of Examples 1 to 8 and Comparative Example 1 produced in this manner were bonded to a non-combustible plate (dielite, manufactured by Daiken Kogyo Co., Ltd.) using a cyanoacrylate adhesive, and then ISO 5660. -1: A heat generation test for 20 minutes was performed by a method based on 2002, and a total heat generation amount was measured. The measurement was performed at n = 3, and the median value was adopted. The results are shown in Table 3.
In the exothermic test, the acceptance criterion is 8.0 MJ / m ² or less.

  From the result of Table 3, in Examples 1-8, the calorific value was small and passed, and in Comparative Example 1, it exceeded the reference value and failed. Comparative Example 1 is considered to be inferior in incombustibility because it has an inorganic content of 20% by mass and a small inorganic content.

(Sheet adhesion evaluation)
The decorative sheets of Examples 1 to 8 and Comparative Example 1 were subjected to a repeated cold test in each environment of 10 cycles of 80 ° C. for 2 hours and −20 ° C. for 2 hours in a state before applying the anchor coat. After the implementation, a cellophane tape peeling test was conducted to check the ink peeling state. The results are shown in Table 4.

  In the results of Table 4, it was determined that the ink adhesion was sufficient. In particular, Examples 5 to 8 having a receiving layer had better ink adhesion than Examples 1 to 4 having no receiving layer.

  From the above evaluation results, it can be seen that the decorative sheet and decorative sheet of the present invention have a low exothermic property even if they are sheets using a polyolefin-based resin, and can be obtained with a design property that does not deteriorate even when thinned. It was.

Since the decorative sheet and decorative plate of the present invention contain a large amount of inorganic components, the amount of combustion heat generated can be suppressed in the exothermic test. In the past, it was necessary to reduce the thickness of the transparent polyolefin resin layer in order to suppress exothermic properties, but instead, only patterns with poor embossing design could be provided, or desired weather resistance could be sufficiently provided. There were problems such as missing. However, these problems are solved in the decorative sheet and decorative plate of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Inorganic substance-containing resin layer 2 ... Pattern layer
3 ... Transparent polyolefin resin layer
4 ... Surface protective layer
DESCRIPTION OF SYMBOLS 10 ... Decorative sheet 12 ... Noncombustible board 13 ... Receiving layer 20 ... Decorative board

Claims (6)

  In a decorative sheet having at least an inorganic substance-containing resin layer, a pattern layer, a polyolefin-based transparent resin layer, and a surface protective layer, the inorganic substance-containing resin layer is in the range of 30 to 110 μm in thickness, and the inorganic substance is 60 to 85% by mass. , 1 to 39% by weight of a hydrocarbon-based resin and 0.01 to 1% by weight of a dispersant, and is characterized by being stretched 1.1 to 5.0 times in the film forming direction. Makeup sheet.   The decorative sheet according to claim 1, wherein the inorganic substance-containing resin layer is further stretched 1.1 to 1.5 times by stretching in a direction perpendicular to the film forming direction.   The decorative sheet according to claim 1 or 2, wherein the inorganic substance contains calcium carbonate as a main raw material.   The inorganic substance contains calcium carbonate as a main raw material and contains at least one selected from the group consisting of pigment, titanium dioxide, talc, mica, and silica as a secondary raw material. A decorative sheet according to any one of the above.   The decorative sheet according to any one of claims 1 to 4, wherein a receiving layer is further provided between the inorganic substance-containing resin layer and the pattern layer.   A decorative board obtained by bonding the decorative sheet according to any one of claims 1 to 5 to an incombustible board.