JP6953909B2 - Decorative sheet and decorative board - Google Patents

Description

The present invention relates to a decorative sheet used as a decorative plate by adhering it to the surface of various decorative substrates such as wood-based boards, inorganic boards, and metal plates with an adhesive, and particularly to a decorative sheet mainly using a polyolefin resin. ..

Conventionally, decorative sheets are laminated to give design to various base materials, and initially, those made of paper or polyvinyl chloride resin were mainly manufactured and used. However, due to the growing interest in environmental issues in recent years, decorative sheets made of polyvinyl chloride resin have been shunned, and polyolefin-based resin-based sheets have been preferably used in place of them.

Various problems have been pointed out from the beginning when switching from polyvinyl chloride resin to polyolefin resin for decorative sheets, but many of them have been solved by the maturity of technology. However, in the part related to non-combustible performance, it has been difficult to impart the same performance as the decorative sheet made of polyvinyl chloride resin with the decorative sheet made of polyolefin resin. Therefore, methods such as reducing the amount of the resin used by adding a flame retardant, thinning the film, or adding an inorganic component have been studied (see, for example, Patent Document 1).

However, there is a concern that the addition of a flame retardant may conflict with the EU (European Union) RoHS Directive and REACH Regulation, etc., because the highly effective bromine-based halogen substance is a halogen substance. There is a problem that thinning the sheet leads to deterioration of the mechanical properties and design of the sheet. If the amount of the inorganic component added is increased, the mechanical properties deteriorate and the production becomes unstable. Therefore, in the former case, the compounding amount is suppressed, in the latter case, the compounding amount is suppressed, or the production rate is slowed down. , Or a combination of both. However, if such a method is adopted, the productivity will be significantly reduced.

Japanese Patent No. 5699703

In view of the above problems, an object of the present invention is to eliminate the limitation that occurs in the conventional olefin-based decorative sheet, that is, it does not use a halogen-based flame retardant, does not cause a design deterioration due to thinning, and is inorganic. It is an object of the present invention to provide an olefin-based decorative sheet and a decorative board having non-combustible performance, which does not reduce the mechanical properties and productivity even if the amount of the material added is increased.
Further, it is an object of the present invention to provide a decorative sheet and a decorative board which enhance the adhesive force at the laminated interface of the olefin resin sheet and are less likely to cause peeling against an external load.

The present invention solves this problem, that is, the invention according to claim 1 is 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 containing the inorganic substance. The resin layer is a mixture in which the total thickness is in the range of 30 to 110 μm, 60 to 85% by mass of the inorganic substance, 1 to 39% by mass of the hydrocarbon resin, and 0.01 to 1% by mass of the dispersant. The outermost layer of the inorganic substance-containing resin layer is stretched 1.1 to 5.0 times in the direction, and the outermost layer is 60 to 85% by mass of the inorganic substance, 1 to 39% by mass of the hydrocarbon resin, and 0.01 to 1 of the dispersant. It is a decorative sheet characterized by being a mixture of a mass% composition and having a component having a melting point of 100 ° C. or lower added to the outermost layer.

The invention according to claim 2 is
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 invention according to claim 3 is
The decorative sheet according to claim 1 or 2, wherein the inorganic substance contains calcium carbonate as a main raw material.

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

The invention according to claim 5 is
A decorative board obtained by attaching the decorative sheet according to any one of claims 1 to 4 to a non-combustible board.

According to the invention according to claim 1, the present invention can obtain a decorative sheet having excellent mechanical properties and productivity while containing a large amount of inorganic components. By performing the stretching treatment on the inorganic substance-containing resin layer, for example, the speed immediately after the film formation is slow, and even if the film is thickened, the sheet is stretched by the subsequent stretching, so that the final production rate is the same. The speed is increased by the stretching ratio, and the thickness is also reduced by the stretching ratio. Further, by stretching, the crystallization of the resin is promoted, so that the mechanical properties are improved. Furthermore, since minute cracks (claws) generated at the interface between the resin and the inorganic substance during stretching diffusely reflect light, it becomes opaque and concealing property can be imparted.

Furthermore, there is a concern that crystallization will proceed due to stretching and the adhesion of ink and adhesive will decrease. However, by containing a low melting point component in the outermost layer of the inorganic substance-containing resin layer, the progress of crystallization can be suppressed. , It is possible to improve the ink adhesion in the subsequent printing process.

Here, the stretching ratio is a value in which the length of the sheet before the stretching treatment is set to 1 and the length of the sheet after the stretching treatment is expressed by the 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 further preferably in the range of 1.8 to 2.5 times. Is. By stretching 1.1 times or more, the effect is effectively exhibited, and by stretching 5.0 times or less, a sheet that does not cause film breakage or surface roughness 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, it is possible to maintain sufficient mechanical properties for practical use and to obtain the necessary concealment property. By setting the thickness to 110 μm or less, the resin content can be reduced to a sufficient amount as a sheet for a non-combustible decorative board. On the contrary, when the thickness is 110 μm or more, the amount of resin used is the same as the amount of resin in the conventional colored raw fabric for decorative sheets, and the manufacturing cost increases and the industrial value decreases.

The invention according to claim 2 makes it possible to improve the tearability of the present invention. The so-called uniaxially stretched sheet stretched only by the peripheral speed ratio of the roll has strong mechanical strength against tension and tearing in the stretching direction, but withstands tension and tearing load in the direction perpendicular to the stretching direction. , It has the property of being easily torn. To compensate for this, stretching of the sheet in the width direction is preferable. Since the main purpose of stretching in the width direction is to impart the minimum mechanical strength, it is not necessary to increase the stretching ratio so much, and the range of 1.1 to 1.5 times is preferable. When the draw ratio exceeds 1.1 times, the effect of improving mechanical properties can be seen, and when it is 1.5 times or less, heat shrinkage in the subsequent process can be suppressed.

Specific examples of the heat shrinkage in the post-process include a drying step after printing, a laminating step of the polyolefin-based transparent resin layer, and a curing step after the laminating is completed. In particular, when the polyolefin-based transparent resin layer is laminated by the extrusion lamination method, heat shrinkage is likely to occur remarkably, but if the draw ratio is set within the range of 1.1 to 1.5 times, It is possible to prevent the problem.

According to the invention according to claim 3, the present invention can obtain an inorganic substance-containing resin layer which is economically inexpensive and has a high proportion of inorganic components without significantly affecting resin molding. The reason is that by using calcium carbonate as the main raw material, the degree of freedom of the shape can be increased in the pulverization process, and the particle size, the smoothness of the surface, and the spherical feeling of the grains can be improved. The average particle size preferably has a 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, and more preferably 2.0 to 5 μm. It is even more desirable if it is within range. If it is 0.5 μm or more, agglomeration at a level that affects the quality is unlikely to occur, and if it is 10 μm or less, calcium carbonate having a large particle size that is stochastically generated may clog the mesh or damage the inside of the extruder. You can avoid the risk of doing so. The higher the smoothness of the surface and the higher the spherical feeling of the grains (closer to the sphere), the higher the content is possible.

The present invention can be further added value by the invention according to claim 4. By adding a pigment, the design of a decorative sheet can be improved, and by adding titanium dioxide, the concealing property can be further improved and the effect of improving the whiteness can be exhibited at the same time. By adding talc, mica, etc., the mechanical strength of the sheet can be further improved.

According to the invention of claim 5, the present invention can obtain a polyolefin-based decorative board made of a decorative sheet containing a large amount of inorganic substances. If a non-combustible plate is used as the base material, even if non-combustible performance cannot be obtained when a conventional decorative sheet of the same thickness is attached, when the decorative sheet of the present invention is attached, the inorganic component is added to the decorative sheet. Since the organic content can be reduced by the amount of a large amount of the above, nonflammable 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 the 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 of an inorganic substance-containing resin layer 1, a pattern layer 2, a polyolefin-based transparent resin layer 3, and a surface protective layer 4.
Layers 1a and 1b containing a low melting point material having a melting point of 100 ° C. or lower are formed on the outermost surfaces of both sides of the inorganic substance-containing resin layer 1.

FIG. 2 shows the cross-sectional structure of the decorative board as a second embodiment of the decorative sheet of the present invention. The decorative board 20 of the present invention is a laminated body in which an inorganic substance-containing resin layer 1 is laminated on a non-combustible board 12 as a base material, and further, a pattern layer 2, a polyolefin-based transparent resin layer 3, and a surface protective layer 4 are laminated in this order. Consists of. Further, layers 1a and 1b containing a low melting point material having a melting point of 100 ° C. or lower are formed on the outermost layers on both sides of the inorganic substance-containing resin layer 1.
The decorative sheet and decorative board of the present invention are not limited to the above drawings and the following description, and even if they have another functional layer or material, they have the same technical features as the present invention. Is included in the present invention.

The polyolefin-based resin used for the polyolefin-based transparent resin layer 3 is not particularly limited, but specifically, in addition to polypropylene, polyethylene, polybutene, etc., α-olefins (for example, propylene, 1-butene, 1- Penten, 1-hexene, 1-heptene, 1-octene, 1-nonen, 1-decene, 1-ethylene, 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-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc. ) Is homopolymerized or copolymerized in two or more types, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, ethylene / A copolymer of ethylene or α-olefin and other monomers such as butyl methacrylate copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer, etc. Can be used.

The inorganic substance used for the inorganic substance-containing resin layer 1 is not particularly limited, but for example, calcium carbonate, titanium oxide, talc, mica (mica), silica, various pigments and the like can be preferably used.

The pattern layer 2 is provided to give the decorative sheet a design such as a wood grain pattern, a stone grain pattern, a sandy 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, concave printing, screen printing, flexo printing, silk printing, electrostatic printing, and inkjet printing is performed on the front surface and / or back surface of the base sheet. Techniques are commonly used, but not necessarily limited to this.

The ink used for the pattern layer 2 is also known, that is, a colorant such as a dye or pigment, a constitutional facial agent is added to the vehicle, and a plasticizer, a radical trapping agent, a wax, a grease, a desiccant, a curing agent, and a thickening agent are added. Agents, dispersants, fillers and the like may be arbitrarily added, diluted sufficiently with a solvent, a diluent and the like, and stirred.

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 common, and other than that, a method of laminating a thermoplastic resin or a surface protective layer in the first place. There is also a method of not providing. There is also a method of selecting one type from these, or in some cases, using two or more types of methods in a hybrid manner.

The surface protective layer 4 is preferably made of an acrylic material, and is preferably a methacrylate-based material in consideration of weather resistance. 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 the scratch resistance by increasing the thickness is hardly observed, but it may be unfavorable in terms of handling and economy.

As the low melting point component, one having controlled stereoregularity or one prepared by a method such as copolymerizing two or more kinds of olefins is preferably used. As an example of the former, tough selenium (manufactured by Sumitomo Chemical Co., Ltd.) can be used, and as an example of the latter, tough mar A, tough mar P, tough mar DF, tough mar XM (all manufactured by Mitsui Chemicals, Inc.), kernel (Japan). Polyethylene (manufactured by Tosoh Co., Ltd.), Lumitac (manufactured by Tosoh Co., Ltd.), Excelene (manufactured by Sumitomo Chemicals Co., Ltd.), etc. can be used. It is also possible to use a product such as Toughmer PN (manufactured by Mitsui Chemicals, Inc.) in which crystalline and amorphous components are mixed.

Hereinafter, the effects will be described based on preliminary experimental examples and examples / comparative examples.

(Preliminary experiment example)
In the preliminary experiment, a sheet to be used as the inorganic substance-containing resin layer 1 was prepared as follows.
High-density polyethylene resin (Hi-Zex 550BR, Meltmas Florate = 0.27 g / 10 minutes, manufactured by Prime Polymer Co., Ltd.) with 29.7 parts by mass and calcium carbonate (Softon 1000) with an average particle size (D50) of 2.2 μm. , Bihoku Powder Industry Co., Ltd.) 70 parts by mass, magnesium 12hydroxystearate (MS-6, manufactured by Nitto Kasei Kogyo Co., Ltd.) as a dispersant 0.3 parts by mass, using a Banbury mixer After kneading, pellet A was prepared by a hot-cut method using a pelletizer.

On the other hand, the same method as above except that an ultra-low density polyethylene resin (Toughmer DF810, manufactured by Mitsui Chemicals, Inc., melting point 66 ° C., melt mass flow rate = 1.2 g / 10 minutes) was used instead of the high density polyethylene resin. Was used to prepare pellet B.

The prepared pellets were sheet-formed using a T-die type 2-type 3-layer single-screw coextruder. The conditions were a set temperature of 200 ° C., a roll nip method for cooling, a lip gap of 1.0 mm, an air gap of 110 mm, a line speed of 10 m / min, and a total film thickness of 70 μm. The rotation speed was adjusted so that the layer ratio was 1/4/1 of the discharge amount. Pellet A was used alone for the intermediate layer, and pellet A and pellet B were dry-blended at a ratio of 70/30 for the outermost layer. However, the film was cut after the T-die of the molten resin was discharged, and stable film formation could not be performed.

When the film-forming thickness was increased to 100 μm, the film was not broken after the T-die was discharged, and by further increasing the film thickness to 200 μm, the film-forming accuracy became possible within a tolerance of 10 μm.

(Examples 1 to 4)
The sheet used for the inorganic substance-containing resin layer 1 produced in Preliminary Experiment Example 1 was stretched using the peripheral speed ratio of the roll while heating at 90 ° C. to reduce the thickness to 70 μm (stretching ratio 2.9 times). A uniaxially stretched sheet A was produced. Further, the biaxially stretched sheet B was produced by chucking the edge of the sheet and stretching it laterally at 95 ° C. to reduce the thickness to 60 μm (stretching ratio 1.2 times).

Preliminary experiments except that 5 parts by weight of calcium carbonate (Softon 1000, manufactured by Bihoku Powder Industry Co., Ltd.) was replaced with titanium dioxide (Typake CR-63, manufactured by Ishihara Sangyo Co., Ltd.). And the same method as the biaxial stretching of Examples was used to prepare a biaxially stretched sheet C containing titanium oxide.

Preliminary experiments and implementations other than replacing 5 parts by weight of calcium carbonate (Softon 1000, manufactured by Bihoku Powder Industry Co., Ltd.) with talc (P-8, manufactured by Nippon Talc Co., Ltd.) out of 70 parts by mass. A biaxially stretched sheet D containing talc was prepared using the same method as in the biaxial stretching of the example.

An isocyanate curing agent was added to gravure ink (XS-756; manufactured by DIC Graphics Corporation), and a coating liquid whose viscosity was adjusted with a methyl ethyl ketone solvent was prepared. The pattern layer 2 was printed using the gravure printing method. On the opposite surface, a gravure ink from which the pigment component had been removed was prepared, and an appropriate amount of silica was added to the gravure ink, which was coated with a gravure coater ^{aiming at a coating amount of 1 g / m 2} (dry). ..

An isocyanate curing agent is added as an anchor coating agent (Takelac_A3210: manufactured by Mitsui Kagaku Co., Ltd.) on the side of the inorganic substance-containing resin 1 after curing where the pattern layer 2 is provided, and the solid content becomes 25% with an ethyl acetate solvent. After diluting as described above and applying with a bar coater ^{aiming at a coating amount of 1 g / m 2} (dry), resin 1 and resin are previously used as shown in Table 1 below using a T-die 2 type 2-layer coextruded laminator. 2 was blended and the kneaded polypropylene resin was coextruded and laminated to form a polyolefin-based transparent resin layer 3.

After that, corona treatment is performed, and as a surface protective layer 4, a hexamethylene diisocyanate-based curing agent and methyl ethyl ketone as a diluting solvent are appropriately added to an acrylate-based coating agent (UC Clear_W480E: manufactured by DIC Graphics Co., Ltd.) to add a bar coater. The coating was applied so that the coating amount was within the range of ^{6 ± 1 g / m 2 (dry).} Then, it was cured in an oven at 40 ° C. for 3 days. In this way, as shown in Table 2, the polyolefin-based decorative sheets of Examples 1 to 4 were prepared.

(Comparative Example 1)
Instead of the sheets A to D prepared in Examples 1 to 4, colored sheets (OW, inorganic content 20% by mass, thickness 60 μm, manufactured by RIKEN TECHNOS CORPORATION) prepared by a T-die extruder were used for comparison. The decorative sheet of Example 1 was prepared. Since this sheet has an inorganic content of 20% by mass, the content of the inorganic substance is lower than that of the above-mentioned example.

(Comparative Example 2)
The decorative sheet of Comparative Example 2 was prepared by using the same method as in Example 1 except that the pellet B used in the low melting point component layers 1a and 1b in Example 1 was not added and was prepared only by pellet A.

<Performance evaluation>
(Fever test)
The decorative sheets of Examples 1 to 4 and Comparative Examples 1 and 2 prepared as described above are attached to a non-combustible decorative board (Dailite, manufactured by Daiken Corporation) using a cyanoacrylate-based adhesive. After the combination, a 20-minute exothermic test was conducted by a method conforming to ISO5660-1: 2002, and the total calorific value was measured. The measurement was performed with n = 3, and the median value was adopted as the numerical value. The results are shown in Table 3. In the exothermic test, the acceptance criterion is ^{8.0 MJ / m 2 or less.}

<Adhesion of surface protection layer>
The decorative sheets of Examples 1 to 4 and Comparative Examples 1 and 2 were placed in each environment of 80 ° C. for 2 hours and -20 ° C. for 2 hours for 10 cycles before the anchor coat was applied, and the cold was repeated. After carrying out the test, a cellophane tape peeling test was carried out to confirm the peeling state of the ink. The results are shown in Table 4.

From the results of Tables 3 and 4, it was determined that the decorative sheet of the present invention has low heat generation and sufficient ink adhesion. On the other hand, Comparative Example 1 using a sheet having a low inorganic content had a large calorific value, and Comparative Example 2 using a sheet containing no low melting point component had poor ink adhesion. From the above, it was found that the decorative sheet of the present invention and the decorative board using the same are excellent in nonflammability and peel strength while using a polyolefin resin.

Since the decorative sheet and the decorative board of the present invention contain a large amount of inorganic components, the amount of heat generated by combustion can be suppressed in the heat generation test. In the past, it was necessary to thin the transparent polyolefin resin layer in order to suppress heat generation, but instead, only a pattern with poor embossing design can be provided, or the desired weather resistance can be sufficiently imparted. There was a problem such as not having it. However, the decorative sheet and the decorative board of the present invention solve these problems. Furthermore, the adhesion of the ink is also improved, and it is considered that there is extremely little possibility that problems such as peeling and floating will occur even after long-term use.

1 ... Inorganic substance-containing resin layer 1a, 1b ... Low melting point component layer 2 ... Pattern layer
3 ... Transparent polyolefin resin layer
4 ... Surface protective layer
12 ... Non-combustible board 10 ... Decorative sheet 20 ... Decorative board

Claims (5)

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 has a total thickness in the range of 30 to 110 μm, and 60 to 85% by mass of the inorganic substance. It is a mixture of 1 to 39% by mass of a hydrocarbon resin and 0.01 to 1% by mass of a dispersant, which is stretched 1.1 to 5.0 times in the film forming direction, and further, the inorganic substance-containing resin layer. The outermost layer is a mixture of 60 to 85% by mass of an inorganic substance, 1 to 39% by mass of a hydrocarbon resin, and 0.01 to 1% by mass of a dispersant, and the outermost layer is a component having a melting point of 100 ° C. or less. A decorative sheet characterized by the addition of. 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 uses calcium carbonate as a main raw material. Claims 1 to 3 are characterized in that the inorganic substance contains calcium carbonate as a main raw material and at least one selected from the group consisting of pigments, titanium dioxide, talc, mica, and silica as an auxiliary raw material. The decorative sheet described in any of. A decorative board obtained by attaching the decorative sheet according to any one of claims 1 to 4 to a non-combustible board.

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