JP7408913B2 - Method for manufacturing decorative sheets and molded products - Google Patents

Description

The present invention relates to a method for manufacturing a decorative sheet and a molded article.

Conventionally, for example, a decorative sheet having a base material layer and a thermoplastic resin layer provided on the surface side of the base material layer has been proposed (see, for example, Patent Document 1). When using the decorative sheet described in Patent Document 1, the decorative sheet is preformed in a mold, the preformed decorative sheet is inserted into an injection mold, and the resin in a fluid state is poured into the injection mold. A molded product is produced by filling the resin into a container and solidifying the resin, and then integrating the solidified resin with a pre-molded decorative sheet.

Patent No. 5055707

However, in the decorative sheet described in Patent Document 1, when forming an uneven pattern on the surface of a molded product, it is necessary to use the side of the injection mold that includes the uneven pattern to be formed. Therefore, even if the molded shapes other than the uneven pattern are the same, if the uneven patterns are different, a plurality of molds are required.
The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a decorative sheet and a method for manufacturing a molded product that can easily form a molded product having an uneven shape.

In order to solve the above problems, one embodiment of the present invention includes (a) a base material layer, (b) a picture pattern layer provided on one side of the base material layer, and (c) a picture pattern layer. (d) a thermoplastic resin layer provided on the surface opposite to the base material layer, and (d) a textured pattern is provided on the surface of the thermoplastic resin layer opposite to the pattern layer A decorative sheet, in which (e) the base layer contains an amorphous thermoplastic resin, and (f) the thermoplastic resin layer contains a crystalline thermoplastic resin having a crystal melting temperature of 150° C. or higher. The gist is that
Further, another aspect of the present invention is to (a) preform a decorative sheet in a preliminary mold, insert the preformed decorative sheet into an injection mold, and pour resin in a fluid state into the injection mold. A method for manufacturing a molded product in which the resin is filled and solidified to integrate the resin and a decorative sheet, the method comprising: (b) a method for manufacturing a molded product in which the temperature of the injection mold is 50°C or higher and lower than 100°C; The gist is that

According to the present invention, the temperature of the decorative sheet can be maintained at the melting point or lower on the surface of the injection mold, and the molding process can be performed while maintaining the uneven shape of the surface of the decorative sheet. Therefore, it is possible to provide a decorative sheet and a method for manufacturing a molded product that can easily form a molded product having an uneven shape.

FIG. 1 is a sectional view showing a decorative sheet according to an embodiment of the present invention.

Hereinafter, a decorative sheet according to an embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and modifications such as changes in design can be made based on the knowledge of those skilled in the art, and forms with such modifications can also be applied to the present invention. included in the range. Further, each drawing is appropriately exaggerated to facilitate understanding.

(composition)
As shown in FIG. 1, the decorative sheet 10 according to the embodiment of the present invention includes a base material layer 1, a picture pattern layer 2 provided on one surface 1a side of the base material layer 1, and a picture pattern layer 2. It has a base material layer 1 and a thermoplastic resin layer 3 provided on the opposite surface 2a side. Further, the outermost surface of the decorative sheet 10, that is, the surface 3a of the thermoplastic resin layer 3 opposite to the picture pattern layer 2 side (hereinafter also referred to as "surface 3a"), has an uneven pattern formed by embossing. 4 is formed. As the uneven pattern 4, for example, a pattern that is synchronized with the pattern of the pattern layer 2, or a pattern that is not synchronized with the pattern can be adopted.
Further, the total thickness of the decorative sheet 10 according to the embodiment of the present invention is not particularly limited, but is preferably 400 μm or more and 550 μm or less. Further, as a method for laminating the base material layer 1, pattern layer 2, thermoplastic resin layer 3, etc., for example, any one of a thermal lamination method, a dry lamination method, a hot melt lamination method, and an extrusion lamination method can be used. .

(Base material layer)
As the material for the base material layer 1, for example, an amorphous thermoplastic resin can be used. As the amorphous thermoplastic resin, for example, ABS resin can be used. ABS resins include, for example, polymer blends of styrene-achloronitrile copolymer and NBR (nitrile rubber), styrene and acrylonitrile in the coexistence of BR (polybutadiene rubber) or SBR (styrene-butadiene rubber) latex. A graft type obtained by copolymerizing with graph can be used. The content ratio of butadiene is preferably 20% by weight or more and 50% by weight or less.

(Picture pattern layer)
The pattern layer 2 is a layer for giving the decorative sheet 10 a design based on a pattern. The picture pattern layer 2 is formed using printing ink, a coating agent, or the like. There are no particular restrictions on the printing ink, and printing inks similar to those used in the pattern layer of conventional decorative sheets can be used. For example, acrylic ink can be used. As the acrylic ink, for example, a two-component curable urethane resin ink made by blending an isocyanate curing agent into an acrylic polyol vehicle can be used. Moreover, as a printing method, for example, a gravure printing method or an offset printing method can be used. Furthermore, any pattern can be used as the pattern, for example, a wood grain pattern, a stone grain pattern, a cloth grain pattern, a cork pattern, an abstract pattern, a geometric pattern, or a combination of two or more of these. can.

(Thermoplastic resin layer)
As the material of the thermoplastic resin layer 3, for example, a thermoplastic resin can be used. As the thermoplastic resin, for example, a crystalline thermoplastic resin having a crystal melting temperature (crystallization temperature) of 150° C. or higher can be used. As the crystalline thermoplastic resin, polypropylene resin is preferred. In particular, homopolypropylene is preferred because of its high melting point. In addition, the thermoplastic resin layer 3 includes low density polyethylene used to soften polypropylene resin, ethylene-α-olefin copolymer, ethylene-propylene copolymer rubber, ethylene-propylene-nonconjugated diene copolymer rubber, A modifier such as a styrene-butadiene copolymer or a hydrogenated product thereof can be added as appropriate. Further, the crystal melting temperature can be measured using, for example, a differential scanning calorimeter (DSC).

(uneven pattern)
The uneven pattern 4 is provided as necessary to give a three-dimensional design to the surface of the decorative sheet 10. As the uneven pattern 4, any uneven shape can be used, for example, wood grain conduit shape, stone grain shape, cloth grain shape, abstract pattern shape, Japanese paper shape, suede shape, leather shape, satin texture, sand grain shape, hairline shape. or a combination thereof. Further, as a method for forming the uneven pattern 4, for example, a doubling embossing method, an extrusion lamination simultaneous embossing method, etc., which are performed before, after, or simultaneously with the lamination of the thermoplastic resin layer 3, can be adopted.

(Other layers)
In addition, the decorative sheet 10 includes a surface protection layer 5, a solid layer 6, etc., as appropriate, in addition to the base layer 1, pattern layer 2, and thermoplastic resin layer 3, similar to conventional decorative sheets. You can. The surface protection layer 5 is provided on the surface 3a side of the thermoplastic resin layer 3. The solid layer 6 is provided between the base layer 1 and the pattern layer 2. In FIG. 1, a solid layer 6, a pattern layer 2, a thermoplastic resin layer 3, and a surface protection layer 5 are laminated in this order on one surface 1a of a base material layer 1.

(Surface protective layer)
The surface protective layer 5 is provided as necessary in order to improve the retention of the surface shape of the decorative sheet 10 and to improve the scratch resistance, stain resistance, and weather resistance of the surface of the molded product after molding. It is a layer. As the material for the surface protection layer 5, for example, curable resin can be used. As the curable resin, for example, an ionizing radiation curable resin or an acrylic urethane resin can be used. An ionizing radiation-curable resin is a composition whose main component is at least one of a prepolymer, an oligomer, and a monomer having a polymerizable unsaturated bond such as a (meth)acryloyl group that has the property of undergoing a crosslinking reaction when irradiated with ionizing radiation. It is. As the ionizing radiation, for example, an electron beam or ultraviolet rays can be used. As the acrylic urethane resin, for example, a reaction product containing an acrylic polyol compound as a main ingredient and an isocyanate compound as a curing agent can be employed.

(solid layer)
The solid layer 6 is a layer provided as necessary to improve the design of the pattern layer 2. As the material for the solid layer 6, a colored thermoplastic resin can be used.

(Method for manufacturing molded products)
The decorative sheet 10 according to the embodiment of the present invention can be laminated onto an adherend made of resin or the like to produce a molded product in which the adherend is decorated. As a method for manufacturing the molded product, for example, an injection molding simultaneous lamination method can be used. In the injection molding simultaneous lamination method, the decorative sheet 10 is preformed in a preliminary mold, the preformed decorative sheet 10 is inserted into the injection mold, and the resin in a fluid state is filled into the injection mold. In this method, the resin and the decorative sheet are integrated by solidifying the resin. At that time, the temperature of the preliminary mold is 120°C or more and less than 130°C. The mold cooling temperature in injection molding is desirably 50°C or higher, because if it is less than 50°C, the spread of the injected resin will be poor, and if it exceeds 100°C, surface shape retention will be poor, so it is preferably less than 100°C.

As explained above, the decorative sheet 10 according to the embodiment of the present invention includes the base material layer 1, the picture pattern layer 2 provided on one surface 1a side of the base material layer 1, and the picture pattern layer 2. The thermoplastic resin layer 3 is provided on the side of the surface 2a opposite to the base material layer 1. Moreover, a concavo-convex pattern 4 is provided on a surface 3a of the thermoplastic resin layer 3 on the side opposite to the pattern layer 2 side. The base material layer 1 contains an amorphous thermoplastic resin, and the thermoplastic resin layer 3 contains a crystalline thermoplastic resin having a crystal melting temperature of 150° C. or higher. Therefore, the temperature of the decorative sheet 10 can be maintained below the melting point on the surface of the injection mold, and the molding process can be performed while maintaining the uneven shape of the surface of the decorative sheet 10. Therefore, it is possible to provide a decorative sheet 10 that can easily form a molded product having an uneven shape.

Moreover, when the molding shape other than the uneven pattern is the same, the same injection mold can be used. Therefore, the number of injection molds can be reduced, and the manufacturing cost of the injection molds can be reduced.
Further, crystalline thermoplastic resins generally have poor thermoformability and have the property of being rapidly deformed. Therefore, by bonding the base material layer 1 containing an amorphous thermoplastic resin to the thermoplastic resin layer 3 containing a crystalline thermoplastic resin as a support layer during molding, moldability can be imparted.
Moreover, in the decorative sheet 10 according to the embodiment of the present invention, the crystalline thermoplastic resin is a polypropylene resin. Therefore, it is relatively easy to obtain and can reduce manufacturing costs.

Further, the decorative sheet 10 according to the embodiment of the present invention further includes a surface protection layer 5 provided on the surface 3a side of the thermoplastic resin layer 3 opposite to the picture pattern layer 2 side. Therefore, the retention of the surface shape of the decorative sheet 10 can be improved, and the scratch resistance, stain resistance, and weather resistance of the surface of the molded product after molding can be improved.
In addition, the decorative sheet 10 according to the embodiment of the present invention is produced by pre-molding the decorative sheet 10 in a preliminary mold, inserting the pre-formed decorative sheet 10 into an injection mold, and injecting fluidized resin. This is a method for manufacturing a molded product in which the resin is filled into a mold and solidified to integrate the resin and the decorative sheet 10. Then, the temperature of the preliminary mold was set to 50°C or more and less than 100°C. Therefore, it is possible to provide a method for manufacturing a molded article that can easily form a molded article having an uneven shape.

Examples and comparative examples of the decorative sheet 10 according to embodiments of the present invention will be described below. Note that the present invention is not limited to the following examples.

(Example 1)
First, as the solid layer 6, a film of random polypropylene resin to which a colored pigment was added was prepared. The thickness of the film was 70 μm. Subsequently, a picture pattern layer 2 was formed using acrylic ink on one side of the solid layer 6 by gravure printing. Subsequently, the thermoplastic resin layer 3 was formed by forming the melted crystalline resin into a film using a T-die. As the crystal melting temperature, for example, homopolypropylene having a crystal melting temperature of 180° C. can be used. The crystal melting temperature was measured with a differential scanning calorimeter (manufactured by PerkinElmer, DSC8500). Then, the thermoplastic resin layer 3 was transferred onto the surface of the solid layer 6 on the picture pattern layer 2 side while transferring the unevenness and cooling and solidifying the thermoplastic resin layer 3 using a cooling roll having an embossed shape.

Subsequently, the surface of the thermoplastic resin layer 3 onto which the unevenness was transferred was coated with an acrylic resin-based thermosetting resin to form a surface protective layer 5. The coating of the surface protective layer 5 was 6 g/m ² in a dry state. In this way, decorative sheet 7 was produced. Subsequently, on the surface of the prepared decorative sheet 7 on the solid layer 6 side, a base material layer 1 made of an amorphous thermoplastic resin (colored ABS resin) with a thickness of 100 μm was laminated. In this way, the decorative sheet 10 of Example 1 was produced.
Subsequently, the manufactured decorative sheet 10 was heated to 130° C. using a preforming mold, and preformed along the preforming mold by air pressure forming. At that time, since the crystalline melting temperature of the crystalline resin (homopolypropylene) constituting the thermoplastic resin layer 3 was 150° C. or higher, the uneven shape transferred by the hot embossing roll withstood the heat pressure. Subsequently, the preformed sheet is inserted into an injection mold, and the ABS resin in a fluid state is filled into the injection mold to solidify the ABS resin and integrate the ABS resin and the decorative sheet 10. A molded product (molded part with decorative unevenness) was obtained.

(Comparative example 1)
In Comparative Example 1, the thermoplastic resin layer 3 was formed by forming a transparent thermoplastic resin (acrylic resin) into a 100 μm thick sheet instead of the crystalline resin. A decorative sheet 10 and a molded product of Comparative Example 1 were obtained in the same manner as in Example 1. Note that, at the time of preforming, the uneven shape transferred by the hot embossing roll had disappeared.

(Comparative example 2)
In Comparative Example 2, the thermoplastic resin layer 3 was formed in the same manner as in Example 1, except that the thermoplastic resin layer 3 was formed using HDPE resin with a crystal melting temperature of 140 ° C. instead of the crystalline resin. Thus, a decorative sheet 10 and a molded product of Comparative Example 1 were obtained. In addition, at the time of preforming, since the preforming mold heated to 100°C, the uneven shape (HDPE resin with a crystal melting temperature of 140°C) transferred by the hot embossing roll was distorted and collapsed.

Therefore, it was confirmed that the decorative sheet 10 of Example 1 could form a molded product having an uneven shape more easily than the decorative sheets 10 of Comparative Examples 1 and 2.

DESCRIPTION OF SYMBOLS 1...Base material layer, 2...Picture pattern layer, 3...Thermoplastic resin layer, 4...Irregular pattern, 5...Surface protection layer, 6...Solid layer, 7...Decorative sheet, 10...Decoration sheet

Claims (3)

a base material layer;
a picture pattern layer provided on one side of the base layer;
a thermoplastic resin layer provided on the side of the picture pattern layer opposite to the base layer;
a surface protective layer provided on a side of the thermoplastic resin layer opposite to the picture pattern layer side,
A decorative sheet in which an uneven pattern is provided on a surface of the thermoplastic resin layer opposite to the picture pattern layer,
The base layer includes ABS resin,
The thermoplastic resin layer includes a crystalline thermoplastic resin having a crystal melting temperature of 150° C. or higher,
A decorative sheet, wherein the surface protective layer contains an acrylic resin. The decorative sheet according to claim 1, wherein the crystalline thermoplastic resin is a polypropylene resin. The decorative sheet according to claim 1 or 2 is preformed in a preliminary mold, the preformed decorative sheet is inserted into an injection mold, and the resin in a fluid state is filled into the injection mold. A method for manufacturing a molded product in which the resin is solidified to integrate the resin and the decorative sheet, the method comprising:
A method for manufacturing a molded article, characterized in that the temperature of the injection mold is 50°C or more and less than 100°C.

Images