JP3099748B2 - Decorative sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin decorative sheet for decorative materials such as plastic decorative plywood or plastic-coated steel sheet used for furniture and building interior materials.

[0002]

2. Description of the Related Art In general, decorative materials such as plastic decorative plywood are obtained by attaching a printed or colored single-layer or laminated resin sheet (decorative sheet) to a base material such as wood such as plywood or a steel plate. Is widely used, and a vinyl chloride resin is widely used as a material of the decorative sheet.

[0003] Such a decorative sheet made of a vinyl chloride resin is widely used as a decorative sheet because it is easily colored and printed, has excellent design properties, and has good adhesion to a base material. I have. However, vinyl chloride resin generates hydrogen chloride gas during incineration disposal after use,
It has been pointed out that such treatment requires time and expense, or that special furnace materials must be used to prevent damage to the incinerator furnace materials. Various uses of resins have been proposed.

However, in the case of polyethylene resins, which are the most general-purpose polyolefin resins, high-density polyethylene has insufficient transparency, while low-density / medium-density polyethylene has good transparency but too low rigidity. Has disadvantages. Further, in the case of the polypropylene-based resin, the rigidity was high, but the bending whitening property was inferior, and it was still insufficient as a decorative sheet.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a decorative sheet comprising a polyolefin resin sheet which has good transparency, high rigidity, and hardly causes whitening due to bending, which has solved the above-mentioned problems. It is.

[0006]

The gist of the present invention is that a melt flow rate is 0.1 to 30 (g / 10 minutes), a heat of crystal fusion is 50 to 100 J / g, and a tensile modulus is 7000 k.
g / cm ² or more and 20000 kg / cm ² or less, a sheet (A) made of a polypropylene resin having a melt flow rate of 0.1 to 30 (g / 10
Min), crystal heat of fusion 30~100J / g, and a tensile modulus of 5000 kg / cm ² or more, a thickness 0.03~2mm formed by laminating a sheet (B) consisting of 7000 kg / cm ² less than the polypropylene resin Tensile modulus is 1000-8
The present invention relates to a decorative sheet using a base sheet of 000 kg / cm ² , and in this decorative sheet, a decorative sheet using a base sheet in which a sheet (B) is laminated on one surface of a sheet (A). There is also a decorative sheet using a sheet and a base sheet in which the sheet (B) is laminated on both sides of the sheet (A).

[0007] Another aspect of the present invention is that the ratio of the thickness of the sheet (A) to the thickness of the base sheet is 5 to 50%.
Wherein the polypropylene resin used for the decorative sheet and sheet (B) is propylene, and one or more olefinic monomers selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms. The decorative sheet described above is a random copolymer with a monomer and the decorative sheet wherein the sheet (B) is made of a polypropylene resin and a saturated styrene block copolymer.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The decorative sheet of the present invention has a base material of a sheet obtained by laminating two types of sheets each made of a specific polypropylene resin (hereinafter referred to as “base sheet for decorative material”).

As such a decorative sheet, for example, 1) a printed layer is formed on a side of the base material sheet for decorative material (B) which is not in contact with the sheet (A), and a transparent layer is formed thereon. A surface layer laminated, 2) a printed layer on the side of the base material sheet for decorative material which is in contact with the base material, and a transparent surface layer formed on the other side, 3) a surface in the above 2) 4) those in which the base material sheet for decorative material is colored with a pigment or the like instead of or in addition to the print layer in the above 1) to 3). .

Generally, a surface layer of a decorative sheet is often provided with a surface layer to improve weather resistance, abrasion resistance, scratch resistance, etc. of the decorative material.
It can be formed by laminating or coating a polyester resin, an acrylic resin, a urethane resin, or the like. This surface layer (in the case of the above (3)) may be embossed on the surface of the base material sheet for decorative material without the printed layer.

The printing layer is formed not only by a printing method such as gravure printing, offset printing, offset gravure printing, or silk screen printing using ink in which a pigment or the like is dispersed, but also by a transfer method. be able to. In order to improve the adhesion between the printed layer and the base material sheet for decorative material, it is desirable to perform a corona treatment on the surface of the base material sheet for decorative material to be printed. Further, it is preferable to provide a primer layer between the base sheet and the printing layer, since the adhesion between them is further improved. Examples of the primer layer include a solution containing a chlorinated polyolefin resin, a polyester resin, an ethylene-vinyl alcohol copolymer, or the like as a main component, and a filler added as necessary.

The base material sheet for the decorative material used in the decorative sheet of the present invention is obtained by laminating a sheet (A) made of a specific polypropylene resin and a sheet (B) made of another specific polypropylene resin on at least one surface. is there. By thus forming a laminate of two or more layers, it has become possible to achieve a good balance between bending whitening resistance and rigidity, which has been conventionally difficult.

In the present invention, the term "polypropylene resin" means a homopolymer of propylene, a block copolymer or a random copolymer mainly composed of propylene, or a mixture of two or more thereof. The melt flow rate of the polypropylene resin used for the sheet (A) needs to be 0.1 to 30 (unit: g / 10 minutes). If the melt flow rate is less than 0.1, molding is difficult and a smooth sheet is difficult to obtain. On the other hand, if it is larger than 30, the melt viscosity becomes too low, and it tends to be difficult to form a sheet.

The heat of fusion of the crystal is 50 to 150 J /
g, preferably 80～140J / g, a tensile modulus of 7000 kg / cm ² or more, 20000 kg / cm ² or less, preferably should be in the range of 10000~15000kg / cm ^2. Heat of crystal fusion is 50 J / g
A sheet having a tensile modulus of less than 7000 kg / cm ² is too soft to be used as the sheet (A) of the base material sheet for a cosmetic material of the present invention. On the other hand, the heat of crystal fusion is 150 J / g, or the tensile modulus is 2000
If it exceeds 0 kg / cm ² , the transparency of the sheet tends to decrease, and the whitening at the time of folding, particularly the bending whitening at low temperature (0 ° C.) tends to be poor.

The heat of crystal fusion referred to in the present invention is defined as DS when the resin is once melted at a temperature equal to or higher than its melting point using a differential scanning calorimeter (DSC) and then cooled at a rate of 10 ° C./min.
It is a value calculated from the crystal peak area on the C chart. The melt flow rate of the polypropylene resin used for the sheet (B) is the same as in the case of the sheet (A).
It needs to be 0.1 to 30 (g / 10 minutes).
If the melt flow rate is less than 0.1, molding is difficult and a smooth sheet is difficult to obtain. On the other hand, if it is larger than 30, the melt viscosity becomes too low, and it tends to be difficult to form a sheet.

The heat of fusion of the crystal is 30-100 J /
g, preferably 50 to 100 J / g, and a tensile modulus of 500 kg / cm ² or more and less than 7000 kg / cm ² ,
Preferably, it must be in the range of 1000 to 6000 kg / cm ² . A sheet having a heat of crystal fusion of less than 30 J / g or a tensile modulus of less than 500 kg / cm ² is too flexible for use as the sheet (B) of the base material sheet for a cosmetic material of the present invention. On the other hand, heat of crystal fusion is 10
When 0 J / g or the tensile modulus exceeds 7000 kg / cm ² , depending on the material of the sheet (A),
The transparency of the base sheet for decorative material is reduced, and whitening at the time of bending, particularly, bending whitening at a low temperature (0 ° C.) is likely to be deteriorated.

The polypropylene resin used for the sheet (B) may be one or more olefin monomers selected from the group consisting of propylene, ethylene and an α-olefin having 4 to 12 carbon atoms. A random copolymer with a polymer is preferred. Such a random copolymer,
The irregular arrangement of the olefinic monomers in the polypropylene disturbs the stereoregularity of the polymer and lowers the crystallinity, resulting in good transparency and high flexibility.

As the olefin monomer, it is preferable to use one or more olefin monomers selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms. Examples of such an α-olefin include butene-1, pentene-1, hexene-1, octene-1, decene-1, and dodecene-1. α
-When the number of carbon atoms of the olefin is 13 or more, random copolymerization tends to be difficult, and thus transparency tends to decrease. The content of the olefin monomer in the copolymer is 1 to 10% by weight, preferably 2 to 6% by weight.

As described above, the polypropylene resin used in the present invention is preferably a random copolymer. However, a homopolymer of propylene, an ethylene / propylene block copolymer, or the like may be used, or the polypropylene resin may be used. Even if a mixture of two or more kinds is used, it can be used without any problem as long as the melt flow rate, the heat of crystal fusion, and the tensile modulus of the resin as a whole fall within the above specific ranges.

Further, it is preferable that the sheet (B) contains the above-mentioned polypropylene resin and a saturated styrene block copolymer, since transparency and flexibility are further improved.
Saturated styrene block copolymer refers to a block copolymer of styrene or a derivative thereof and a conjugated diene-based monomer such as butadiene that is hydrogenated to be a saturated type, for example, hydrogenated styrene-butadiene. AB type or AB
A-type block copolymer, hydrogenated styrene-isoprene AB
A type block copolymer, etc. can be exemplified, and industrially,
It is sold under trade names such as "Clayton G" (Shell Chemical), "Toughtec" (Asahi Kasei Kogyo), "Dynalon" (Nippon Synthetic Rubber) and the like.

The polypropylene resin used for the sheet (A) and the sheet (B) may contain, if necessary, an antioxidant, a weathering aid (a hindered amine light stabilizer, an ultraviolet absorber, etc.), a slip agent, and a coloring agent. , A filler, a nucleating agent and the like can be added within a range that does not impair the purpose and performance thereof.
As a method of forming the polypropylene-based resin into the base material sheet for decorative material, a general sheet forming method may be used, and there is no particular limitation. For example, a T-die extrusion method, an inflation molding method, a calender molding method and the like can be mentioned.

As a method for laminating the sheet (A) and the sheet (B), individual sheets are formed beforehand.
A lamination method using a laminator or the like, a method of pressing and fusing at the same time as forming a sheet, and a method of fusing can be used. However, a two-layer (or multilayer) T-die extrusion method creates a laminated sheet at the same time as forming. It is preferable to reduce the number of steps.

In the present invention, the laminated base sheet needs to have a tensile modulus of 1000 to 8000 kg / cm ² . If the tensile modulus is out of this range, the rigidity is insufficient or excessive, and the bending whitening property is deteriorated, making it difficult to use as a base sheet for a decorative sheet. The ratio of the thickness of the sheet (A) to the thickness of such a laminated base sheet is preferably 5 to 50%. The thickness of the sheet (A) in the entire base sheet is less than 5%,
If it exceeds 0%, the balance between rigidity and bending whitening property, which is the object of the present invention, is lost, and the sheet becomes too flexible or too hard, which is not suitable for a decorative sheet.

The thickness of the base sheet for a decorative material varies depending on the layer structure of the decorative sheet and its use.
About 2 mm is preferable. Using such a base sheet, a decorative sheet manufactured by the above-described method can be laminated with a base material such as plywood or a steel plate using an adhesive or an adhesive to produce a decorative material.

[0025]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited by the following Examples unless it exceeds the gist of the invention. <Examples 1 to 4, Comparative Examples 1 and 2> Using a polypropylene resin shown in the table, a 40 mmφ + 30 mmφ T-die extruder (two-layer extruder, T-die: 400 mm width) and a condition of a die temperature of 220 ° C. Then, the sheet (A) and the sheet (B) were laminated at the same time as the molding to form a base sheet for decorative material having a thickness of 100 μm. In Example 4, the total amount of the resin in the polypropylene resin for the sheet (B) was 2%.
A saturated styrene block copolymer in an amount corresponding to 0% by weight was mixed and used.

The following evaluation was performed on the obtained sheet. The results are shown in the table. <Evaluation method> 1. Melt flow rate: Measured according to JIS K 6758 (and JIS K 7210). 2. Moldability: The appearance of the T-die molded sheet was visually judged according to the following criteria.

○: good △: some flow mark ×: poor fluidity, uneven flow Tensile test: Measured at a tensile speed of 50 mm / min using a dumbbell No. 1 test piece in accordance with JIS Z 1707. 4. Bending whitening property: The degree of whitening of a bent portion when bent at 180 ° in an atmosphere of 0 ° C. was visually determined according to the following criteria.

○: no whitening Δ: slight whitening ×: marked whitening Haze: The haze was measured according to JIS K 7105. <Preparation of Cosmetic Sheet and Cosmetic Material> Each sheet of the above example was used as a base material sheet for a cosmetic material, a corona treatment was applied to one surface, and a primer mainly composed of a chlorinated polyolefin resin was applied. Wood-grain printing was performed on the treated sheet by gravure printing, and the same transparent sheet as the above-mentioned base sheet was laminated again, followed by embossing to produce a decorative sheet.

A corona treatment was further applied to the back surface to apply an adhesive, and a plywood was adhered as a base material to prepare a decorative material. Since this decorative material has excellent bending whitening resistance of the decorative sheet, there is no whitening phenomenon at corners,
It had a good appearance. In addition, the decorative material manufactured from the decorative sheet of the comparative example made using the decorative material base sheet whose tensile elastic modulus is out of the preferable range of the present application causes whitening at the corners of the backing material and is inferior in quality. Was something. <Summary of Results> The base sheet for decorative material of the comparative example in which the tensile elastic modulus as a base sheet after lamination is out of the range of the present invention was inferior in bending whitening property and also tended to deteriorate haze. . Also, when a decorative sheet and a decorative material were used, whitening was likely to occur at the bent portion, and only poor quality products were obtained.

[0030]

[Table 1] (Note) Resin type: FY6C: Polypropylene homopolymer (manufactured by Mitsubishi Chemical) SPX: SPX8600 (polypropylene copolymer) (same) 1320P: Tainalon 1320P (saturated styrene block copolymer) (Made by Nippon Synthetic Rubber) MFR : Melt flow rate Tensile modulus: Unit kg / cm ² Saturated ST-B polymer: Saturated styrene block copolymer

[0031]

The decorative sheet obtained by using the base material sheet for decorative material of the present invention obtained by laminating the sheets comprising the specific polypropylene resin has a low haze and good transparency, and thus has a good appearance. In addition, bending and whitening hardly occur.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tatsuya Ochiai 2 Okaike, Iwazuka-cho, Nakamura-ku, Nagoya-shi, Aichi Prefecture Mitsubishi Chemical MKV Corporation Nagoya Office (72) Inventor Takeshi Furuya 2 Oiketsu, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi Prefecture Address Mitsubishi Chemical MKV Corporation Nagoya Office (56) References JP-A-10-36590 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (6)

(57) [Claims] 1. A melt flow rate of 0.1 to 30 (g)
/ 10 min), heat of crystal fusion of 50 to 100 J / g, and tensile modulus of 7000 kg / cm ² or more, 20,000 kg
/ Cm ² or less of a sheet of polypropylene resin (A) having a melt flow rate of at least one side.
1 to 30 (g / 10 minutes), heat of crystal fusion is 30 to 100 J
/ G, and the tensile modulus is 5000 kg / cm ² or more, 7
A sheet (B) made of a polypropylene resin having a thickness of less than 000 kg / cm ² and having a thickness of 0.03 to 2 mm,
A decorative sheet using a base sheet having a tensile modulus of 1000 to 8000 kg / cm ² . 2. The decorative sheet according to claim 1, wherein a base sheet is used in which the sheet (B) is laminated on one side of the sheet (A). 3. The decorative sheet according to claim 1, wherein the base sheet is formed by laminating the sheet (B) on both sides of the sheet (A). 4. Sheet (A) with respect to thickness of substrate sheet
The decorative sheet according to any one of claims 1 to 3, wherein a thickness ratio of the decorative sheet is 5 to 50%. 5. The polypropylene resin used for the sheet (B) comprises propylene, ethylene and 4-1 carbon atoms.
The decorative sheet according to any one of claims 1 to 4, wherein the decorative sheet is a random copolymer with one or two or more olefin monomers selected from the group consisting of α-olefins. 6. The sheet (B) comprising a polypropylene resin and a saturated styrene block copolymer.
The decorative sheet according to any one of items 5 to 5.