JP2001011206A - Polypropylene sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene sheet satisfactorily retaining surface gloss after thermoforming by laminating a thin film layer with a gross-retaining layer based on a polypropylene resin layer in the given order and specifying a change in surface gross before and after thermoforming. SOLUTION: A 30-200 μm thick gross retaining layer made from a composition containing 100 pts.wt. polypropylene resin and 0.05-5 pts.wt. nucleator is laminated on a 30-200 μm thick thin resin film layer to obtain a polypropylene sheet which has a surface gross of 40 or above before thermoforming and undergoes a change in surface gross of 20 or below when thermoformed. The polypropylene sheet can be produced, for example, by uniting a starting film having a gross retaining layer with a thin resin film layer by a process such as casting or extrusion and laminating them by a process such as thermal lamination, extrusion lamination, or dry lamination using an adhesive. It is possible that the gross retaining layer is a colored one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene sheet, and the sheet maintains good surface gloss even after thermoforming. The resin molded product whose surface is covered with the sheet is suitably used for building materials, automobile parts, stationery and the like.

[0002]

2. Description of the Related Art Conventionally, vinyl chloride resins have been widely used for house building materials, but polyolefin resins have tended to be used in the flow of vinyl chloride in recent years. Also, plastics are used for interior and exterior parts of automobile parts and the like for design and lightness. In these fields, polypropylene-based resins are widely used, particularly in view of price and moldability.

[0003] The polypropylene resin is formed into a sheet, and the sheet is used after being thermoformed. In order to enhance the design and surface characteristics in the sheet stage, an acrylic resin, polyester, or 2. Description of the Related Art Lamination of a thin resin film layer of a base resin, a fluorine resin or the like has been performed. However, even if the polypropylene resin sheet itself has gloss on its surface, the surface becomes matte during thermoforming such as vacuum forming, and the surface of the thin film resin film layer laminated on the surface also becomes As a result, the surface becomes matte, and the surface gloss significantly changes before and after the thermoforming.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves these problems, and a polypropylene having a surface gloss before thermoforming of 40 or more and a change in surface gloss after thermoforming of 20 or less. An object of the present invention is to provide a system sheet, a sheet molded product comprising the same, and a resin molded product whose surface is covered with the sheet molded product.

[0005]

The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, by providing a gloss holding layer containing a crystal nucleating agent mainly composed of a polypropylene-based resin, The present inventors have found that a sheet molded product which maintains the surface gloss even by heating during molding can be obtained, and the present invention has been completed. That is, the present invention
(1) A polypropylene-based sheet formed by laminating a thin-film resin film layer and a gloss-maintaining layer mainly composed of a polypropylene-based resin in this order, having a surface gloss before thermoforming of 40 or more and a surface gloss after thermoforming. A polypropylene-based sheet characterized in that the change is 20 or less, (2) a thin film resin film layer, a gloss-maintaining layer mainly composed of a polypropylene-based resin, and a polypropylene-based sheet laminated in the order of a base material layer, A polypropylene sheet having a surface gloss before molding of 40 or more and a surface gloss change after thermoforming of 20 or less, and (3) printing and / or printing between the thin resin film layer and the gloss holding layer. Alternatively, the polypropylene sheet according to (1) or (2), which has a layer for adhesion, and (4) the gloss retaining layer has a thickness of 30 to 200 μm. Polypropylene sheet according to any one of 1) (3), (5) a crystal nucleating agent gloss retention layer relative to 100 parts by weight of polypropylene resin 0.0
The polypropylene sheet according to any one of (1) to (4), which is contained in an amount of not less than 5 parts by weight and not more than 6 parts by weight, and (6) the gloss retaining layer is colored. Any one of (2) to (6), wherein the polypropylene sheet according to any one of (1) to (5), (7) the gloss retention layer and / or the base material layer are colored. Item (8): Polypropylene sheet according to item (8)
(9) a raw material sheet which becomes a polypropylene-based sheet according to any one of (1) to (7) by laminating the thin film resin film layer without having the thin film resin film layer;
(1) A sheet molded product comprising the polypropylene sheet according to any one of (7), (10) and a sheet molded product according to (9), wherein the resin molded product is covered with the thin film resin film layer as a surface side. ,.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The polypropylene sheet of the present invention is obtained by laminating a thin film resin film layer and a gloss holding layer mainly composed of a polypropylene resin. In addition, a thin film resin film layer / a gloss holding layer / a thin film resin layer having a polypropylene resin base layer containing a polypropylene resin as a main component below the gloss holding layer.
A three-layer structure of a polypropylene-based resin base material layer is also a preferable structure in the present application. In addition to the resins, additives generally used in each layer, for example, ultraviolet absorbers, heat stabilizers, lubricants, antistatic agents such as various surfactants, antifogging agents, and stabilizers such as antioxidants can be added. . In addition, a thermoplastic resin other than the polypropylene resin, for example, polyethylene, can be added to the gloss retaining layer and the polypropylene resin substrate layer as long as the amount is up to 40% by weight.

[0007] The polypropylene resin used in the present invention is a propylene homopolymer obtained by homopolymerizing propylene, or an unsaturated organic acid such as a comonomer, acrylic acid ester, or maleic acid of 20% by weight or less, and the same. Copolymers obtained by copolymerizing monomer units such as anhydrides and α-olefins having 4 to 12 carbon atoms with propylene are exemplified. Further, there may be mentioned those obtained by introducing a long-chain polypropylene as a branched chain into a polypropylene-based resin main chain by a method such as irradiation with radiation. Alternatively, modified products such as oxidation and chlorination of these polymers may be used. In the practice of the present invention, these polypropylene resins may be used alone or in combination of two or more.

In the polypropylene sheet of the present invention, a gloss retaining layer is laminated next to the thin resin film layer. Here, the gloss retaining layer is a layer mainly composed of a polypropylene-based resin to which a crystal nucleating agent is added.

As the crystal nucleating agent of the present invention, various organic and inorganic materials known as crystal nucleating agents for polypropylene resin can be used. For example, inorganic materials: talc (magnesium silicate), organic Materials: (1) metal carboxylate / sodium benzoate, aluminum benzoate, potassium benzoate, lithium benzoate,
Sodium β-naphthalate sodium cyclohexanecarboxylate, aluminum hydroxydiparat-butylbenzoate, (2) benzylidene sorbitol and its derivative type / dibenzylidene sorbitol, dimethyl benzylidene sorbitol, sorbitol acetal, (3) polymer type / poly- 3-methylbutene-1, polyvinylcycloalkane, polyalkenylsilane, EPR (ethylene propylene rubber), Kevlar fiber, (4) other / 2,2-methylenebis (4, phosphate)
6-di-t-butylphenyl) sodium and various pigments. Among them, aluminum hydroxydipara-t-butylbendate can be suitably used. Also,
When various pigments are used, it is possible to simultaneously impart coloring and surface gloss.

The amount of the nucleating agent added is adjusted so that the surface gloss of the polypropylene sheet after thermoforming is 40 or more. The specific amount varies depending on the type of the nucleating agent. It is in the range of 0.05 to 6 parts by weight based on parts by weight. In particular, the addition amount is preferably 0.05 to 5 parts by weight for an organic material-based crystal nucleating agent and 0.5 to 6 parts by weight for an inorganic material-based nucleating agent. If the addition amount is small, even if the surface gloss of the gloss retaining layer is increased to 40 or more and the surface gloss is increased to 40 or more, the decrease in the surface gloss after thermoforming becomes 20 or more. Also, if the amount is too large, the decrease in surface gloss after thermoforming tends to increase. If the surface gloss of the polypropylene-based sheet before thermoforming is less than 40, the unevenness of the surface of the gloss retaining layer becomes remarkable, and even if the thin film resin film layer is laminated, it is affected by the unevenness of the surface of the gloss retaining layer after thermoforming. 20 decrease in surface gloss
That's all.

The thickness of the gloss holding layer is not less than 30 μm and 200
It is preferably not more than μm. If the thickness is too thin, the effect of the gloss holding layer is small and the change in surface gloss becomes large. Also, when the thickness of the gloss holding layer is increased, there is a problem that the thermoformability of the polypropylene sheet is added and the cost is increased.

In the present invention, the thin film resin film layer laminated on the polypropylene sheet has a thickness of 30 μm or more and 20 μm or more.
A resin film having a thickness of 0 μm or less.
Those having a size of 20 μm or less can be suitably used. As the resin to be used, a thermoplastic resin can be suitably used, for example, an acrylic resin, a polyester resin,
Fluorinated resins and the like can be used alone or in combination. Above all, a thin film resin film layer containing a vinylidene fluoride resin as a main component or a vinylidene fluoride resin and a methyl methacrylate resin as main components can be suitably used. These resins may contain additives generally used, for example, UV absorbers, heat stabilizers, lubricants, stabilizers such as antistatic agents such as various surfactants, antifogging agents, and antioxidants.

The polypropylene-based sheet of the present invention is prepared by, for example, separately casting and extruding a thin film resin film layer on a film of a raw material having a gloss holding layer, and using a heat lamination, extrusion lamination or an adhesive. It can be manufactured by laminating by a known method such as dry lamination. Alternatively, it is also possible to directly coat the surface of the gloss retaining layer and laminate a thin resin film layer, or to laminate the same at the time of forming a polypropylene sheet. Further, a single layer or multiple layers can be further laminated below the gloss holding layer or the base layer. It is also possible to provide an adhesive layer between the gloss holding layer and the thin resin film layer,
It is also possible to provide a printing layer such as gravure printing.

In the present invention, thermoforming refers to a method in which a sheet of a polypropylene-based resin is heated and softened, and an external force is applied while the sheet is soft to form the sheet. Thermoforming includes a wide variety of methods such as a method using air as an external force, a method using male and female dies, and a method combining these, but is not particularly limited. For example, straight vacuum forming,
Examples include straight pressure forming, drape vacuum forming, plug assist vacuum forming, match mold forming, and injection in mold forming which combines vacuum forming and injection molding.

[0015]

(Example 1) Two layers, a gloss-retaining layer, 2.0 parts by weight of talc (talc FVS, Shiroishi Calcium Co.) as a nucleating agent for 100 parts by weight of a polypropylene resin (JSG homopolymer of Grand Polymer Co., Ltd.) Part, and using a polypropylene resin (Grand Polymer EB-4476 homopolymer) as a base material layer,
A film was formed by a co-extrusion method using a feed block so that the gloss retaining layer had a mirror-finished finish. The thickness of the gloss holding layer was 100 μm, and the thickness of the substrate layer was 400 μm. A commercially available acrylic resin film (transparent, 50 μm thick) was laminated on the sheet as a thin resin film layer by a heat lamination method. After measuring the surface glossiness of the laminated sheet on the side of the thin resin film layer at a mirror gloss of 60 degrees according to JIS K7105, the sheet is heated to a sheet surface temperature of 180 degrees, and subjected to thermal vacuum molding to form a molded product (length 210 × width 205 × Height 25m
m). The surface gloss of the bottom surface was measured in the same manner.
Similarly, for the sheet before laminating the thin film resin film layer, the surface glossiness of the gloss retaining layer side is measured at 60 ° specular glossiness according to JIS K7105, then heated to a sheet surface temperature of 180 ° C, and subjected to thermal vacuum molding to form a molded product ( Length 210 x width 205
× height 25 mm). The surface gloss of the bottom surface was measured in the same manner.

(Example 2) In Example 1, 1.5 parts by weight of a commercially available phthalocyanine pigment (blue) was added as a nucleating agent. The thickness of the gloss holding layer was 150 μm, and the thickness of the base material layer was 350 μm. A commercially available tetrafluoroethylene-ethylene copolymer film (black, 30 μm thick) was laminated by a dry lamination method as a thin film resin film layer. Thermoforming was performed in the same manner as in Example 1, and the surface glossiness was measured.

Example 3 In Example 1, commercially available dimethylbenzylidene sorbitol was used as a nucleating agent in an amount of 0.3%.
Parts by weight were added. The thickness of the gloss holding layer was 40 μm, and the thickness of the base material layer was 210 μm. As a thin resin film layer, a Denka DX film (transparent, 40 μm thick, vinylidene fluoride / PMMA resin film) was laminated by a dry lamination method. Thermoforming was performed in the same manner as in Example 1, and the surface glossiness was measured.

EXAMPLE 4 2.0 parts by weight of talc (talc FVS, Shiroishi Calcium Co., Ltd.) was used as a crystal nucleating agent for 100 parts by weight of a polypropylene resin (JSG homopolymer of Grand Polymer Co., Ltd.) consisting of a single layer of a gloss holding layer. A 200 μm sheet was obtained by extrusion using the added resin. Further, as a thin resin film layer, a Denka DX film (transparent, 40 μm thick, vinylidene fluoride / PMMA resin film) was laminated by a thermal laminating method. Thermoforming was performed in the same manner as in Example 1, and the surface glossiness was measured.

Comparative Example 1 A 200 μm sheet was obtained by an extrusion method using a polypropylene resin (JSG homopolymer of Grand Polymer Co., Ltd.). Further, as a thin resin film layer, a Denka DX film (transparent, 40 μm thick, vinylidene fluoride / PMMA resin film) was laminated by a thermal laminating method. Example 1
In the same manner as described above, thermoforming was performed and the surface glossiness was measured.

Comparative Example 2 In Example 3, the amount of dimethylbenzylidene sorbitol added was 0.03 parts by weight.

Comparative Example 3 In Example 1, the amount of talc added was 10 parts by weight.

[0022]

[Table 1]

[0023]

According to the present invention, a polypropylene-based sheet capable of maintaining the surface glossiness of a thin-film resin film layer even after laminating the thin-film resin film layer and further thermoforming, a sheet having a thin-film resin film layer laminated on the sheet And a molded article comprising the same.

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Claims (10)

[Claims] 1. A polypropylene-based sheet having a thin film resin film layer and a gloss-maintaining layer mainly composed of a polypropylene-based resin laminated in this order, wherein the surface gloss before thermoforming is 40.
As described above, the change in surface gloss after thermoforming is 20 or less. 2. A polypropylene sheet laminated in the order of a thin film resin film layer, a gloss-maintaining layer mainly composed of a polypropylene resin and a substrate layer, and has a surface gloss before thermoforming of 40 or more, and is thermoformed. A polypropylene-based sheet, wherein a change in surface gloss after that is 20 or less. 3. The polypropylene sheet according to claim 1, further comprising a layer for printing and / or adhesion between the thin resin film layer and the gloss holding layer. 4. The polypropylene sheet according to claim 1, wherein the gloss holding layer has a thickness of 30 to 200 μm. 5. A gloss-maintaining layer comprising a polypropylene resin 100
The polypropylene sheet according to any one of claims 1 to 4, wherein the polypropylene sheet contains 0.05 to 6 parts by weight of a nucleating agent based on parts by weight. 6. The polypropylene sheet according to claim 1, wherein the gloss retaining layer is colored. 7. The polypropylene sheet according to claim 2, wherein the gloss holding layer and / or the base material layer are colored. 8. The method according to claim 1, wherein the thin film resin film layer is laminated without the thin film resin film layer.
A raw material sheet to be the polypropylene-based sheet according to any one of the above. 9. A sheet molded article comprising the polypropylene-based sheet according to any one of claims 1 to 7. 10. A resin molded product according to claim 9, wherein the thin film resin film layer is covered on the surface side.