Concave molded product and method for manufacturing the same

Abstract

To provide a concave molded product with a gradation part where the appearance steplessly changes depending on a color tone, a pattern, or the like on artificial marble, and a method for molding the same.SOLUTION: A bathtub 10 forming a concave molded product is formed by providing a resin compound layer 20 forming an artificial marble base material with an opening at the upper part, a light-transmitting surface protective layer 22 on the inner surface of the base material, and a back protective layer 25 on the outer surface of the base material. A gradation part 23 is provided between the compound layer 20 and the surface protective layer 22 along a vertical direction. A state where an appearance pattern and the like of artificial marble gradually fade from top to bottom appears.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a concave molded product and a manufacturing method thereof, and more particularly to a concave molded product of artificial marble having a gradation portion and a manufacturing method thereof. [Background technology]

[0002] It has been proposed to provide a design for concave molded products such as bathtubs by applying a colored gel coat to the upper edge surface or its vicinity using masking tape to create different surface features (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-49188 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the bathtub described in Patent Document 1, a boundary is created with masking tape and then a colored gel coat is applied, thereby characterizing the taped area and the gel coat applied area as two different surfaces, creating a two-tone appearance across the boundary. Therefore, a linear boundary line will appear on the bathtub, which may look unnatural depending on the design of the bathtub, and it cannot be said that the design is suitable for general use. Furthermore, the task of applying masking tape to the upper edge of the bathtub or in its vicinity becomes unavoidable, which not only increases the number of work steps but also creates the constraint of requiring a certain level of skill. Furthermore, when the masking tape is peeled off, the adhesive becomes pulled into threads, causing it to adhere to the surface of the molded product.

[0005] Incidentally, concave molded products such as bathtubs and wash basins made of artificial marble are made using a resin compound as the molding material, and various additives such as colorants, resin particles, and pattern materials are added to this, so that the color tone, brightness, saturation, pattern materials, etc. are evenly displayed throughout the molded product, and the high quality texture has led to their widespread adoption and popularity. However, there is still no known concave molded product with a design in which, for example, the appearance of the color tone or pattern material changes gradually and steplessly or continuously in a predetermined direction within the surface of the artificial marble. This is because the molded product is formed by the flow of the resin, which is the molding material of the artificial marble, and additives such as the pattern material added to it, inside the molding die, and therefore it is not possible to control the appearance of a part of the molded product to change.

[0006] [Objective of the Invention] The object of the present invention is to provide a concave molded product based on a molded product made of artificial marble and having a gradation portion in which the color tone, brightness, saturation, pattern, design, etc., appearing in its appearance change steplessly, and a molding method for the same. Another object of the present invention is to provide a concave molded product that can be molded without the need for masking tape, and a method for producing the same. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention employs the configurations described in the claims. Specifically, A concave molded article of artificial marble comprising a resin compound layer having an opening at the top and a light-transmitting surface protective layer provided on the inner surface of the resin compound layer, A gradation portion is provided along a predetermined direction between the resin compound layer and the surface protection layer.

[0008] In the present invention, the gradation portion is formed by spraying a colored paint in the form of dots, the colored paint being obtained by adding a colored toner to a clear paint, and the colored paint contains a colored toner of a similar color to the colored particles contained in the resin compound layer, thereby forming the gradation portion.

[0009] Further, the dot density is configured to increase gradually from the top to the bottom when the opening side is the top.

[0010] The present invention also provides a method for producing a concave molded product made of artificial marble having a resin compound layer with an opening at the top and a light-transmitting surface protective layer located on the surface of the resin compound layer, using a mold including a convex mold and a concave mold, comprising: applying a gel coat resin mixture to the convex mold to form a surface protective layer; spraying a material for forming a gradation portion onto the surface protective layer; and after injecting the resin compound into the concave mold, clamping the mold to allow the resin compound to flow into the molding mold and form a concave shape. The gradation portion is formed by gradually increasing or decreasing the dot density by spraying colored paint in a predetermined direction.

[0011] The resin compound layer in the present invention is formed by blending additives such as fillers, pattern materials, reinforcing materials, and curing agents with a thermosetting resin. Examples of the thermosetting resin include polyester resins, acrylic resins, and epoxy resins. Thermosetting resins of various colors can be used, but in order to obtain the texture and luxury of natural marble, a resin with a color similar to that of natural marble can be used. Various fillers can be used, but it is preferable to use inorganic filler fine powders such as alumina, aluminum hydroxide, barium sulfate, silica, glass powder, and calcium carbonate. The pattern material contained in the resin compound layer may be granules obtained by crushing plastic materials colored with inorganic or organic dyes or pigments, or granules obtained by crushing natural stones such as artificial marble and mica, and may be of various colors, shapes, and sizes. However, in order to obtain the appearance and luxury of natural marble, it is preferable to use a material of a color, shape, and size similar to that of natural marble.

[0012] The surface protective layer can be formed using a mixed solution of a light-transmitting polyester gel coat resin, a curing agent, and a styrene monomer. The surface protective layer can also be formed by mixing a small amount of one-color or multi-color toner to match the color tone of the resin compound layer. The surface protective layer can be formed, for example, by applying the mixed solution to a mold to which a release agent has been applied in advance using a spray gun. The thickness of the surface protection layer is preferably set to 0.15 mm to 0.6 mm. By setting the thickness to 0.15 mm or more, the resin compound layer can be well protected. Also, by setting the thickness of the surface protection layer to 0.6 mm or less, sagging of the vertical surface of the surface protection layer and the occurrence of cracks during curing can be prevented.

[0013] The gradation portion is made of a colored paint in which a colored toner is added to a clear paint, and it is preferable to add a colored toner of the same color as the colored particles contained in the resin compound layer. In the case of a colored toner of a different color, it can be seen that the surface protection layer is decorated, not the compound layer, but depending on the method of application, unnaturalness may appear. In the case of colored toners of similar colors, it is possible to make it look like "a gradation part is formed in the compound layer," which is difficult to achieve in terms of molding. In addition, it is possible to absorb the variation in the skill of the workers. Furthermore, by approximating the size of the dots to the colored particles contained in the resin compound layer, it is possible to further improve the affinity between the gradation part and the compound layer. Here, the clear coating contains the mixed liquid that forms the surface protection layer.

[0014] It is preferable to provide a back surface protective layer that does not have light transmittance on the back surface of the resin compound layer that becomes the outer surface of the molded product, i.e., the surface opposite to the surface on which the surface protective layer is provided. This back surface protective layer acts to prevent light from passing through the artificial marble, and can be formed, for example, by mixing and stirring a white or black gel coat resin, a hardener, and a styrene monomer to form a mixed liquid, and then spraying the mixed liquid. In addition, the material for forming the gradation portion can be sprayed in a large amount, i.e., by spraying dots at a high density, so that light cannot pass through. In this case, the process of forming the gradation portion and the process of forming the back surface protective layer can be performed consecutively without changing the material. Effect of the Invention

[0015] According to the present invention, a concave molded product made of artificial marble can be provided that exhibits a very natural appearance in which the appearance changes gradually and steplessly in a specified direction while maintaining the high quality texture of the artificial marble, thereby providing a novel type of concave molded product that has not been seen before. Furthermore, the boundaries seen in the conventional example do not appear, and the present invention can be applied universally without restrictions even when the shapes and designs of molded products are variously different. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic front view of a bathtub constituting the concave molded product of the present embodiment. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a portion of FIG. [Diagram 3] 5 is a schematic cross-sectional view for explaining a method for producing the concave molded product. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification, unless otherwise specified, terms indicating positions or directions such as "up and down," "left and right," etc. are used based on the state in which the bathtub is viewed from the front as shown in Figure 1. Please also understand that the aspect ratios, layer thickness dimensions, etc. of the drawings are changed as necessary for the convenience of making the configuration easier to understand.

[0018] As shown in Figure 1, the bathtub 10 constituting the concave molded product is made of a horizontally long artificial marble whose left-right length is longer than its top-to-bottom height. This bathtub 10 is composed of a peripheral wall 12 with a flange portion 11 connected to the outer periphery of the upper end, and a bottom wall 15 with a step 13 for half-bathing provided via a step wall 14 on one side in the left-right direction in the figure. As shown in Figures 2 and 3, the layer structure of the bathtub 10 consists of a resin compound layer 20 which forms the main part or base material of the artificial marble, a light-transmitting surface protective layer 22 provided on each surface of the inner side of the resin compound layer 20 and the upper side of the flange portion 11, a gradation portion 23 provided between the resin compound layer 20 and the surface protective layer 22, a concealing layer 24 provided from the lower end of the gradation portion 23 to the lower inner surface of the step 13, the step wall 14, the bottom wall 15 and the peripheral wall 12 to conceal the resin compound layer 20, and a back surface protective layer 25 provided on the underside of the flange portion 11 and the outer surface of the resin compound layer 20.

[0019] In this embodiment, the gradation portion 23 is provided on the entire circumference of the peripheral wall 12 between a position corresponding to the lower surface of the flange portion 11 and a position corresponding to the upper surface of the step 13 of the half-bath. The gradation portion 23 is formed by spraying a colored paint, which is a clear paint with a colored toner added thereto, onto the surface protective layer 22, as described below. This spraying is performed in such a manner that the dot density of the paint is gradually higher downward than upward. Therefore, it is possible to present a stepless change in which the resin compound layer 20, i.e., the artificial marble, is clearly visible at the top through the gradation portion 23, and gradually becomes less visible toward the bottom, and the artificial marble becomes invisible at the bottom end of the gradation portion 23. Note that in FIG. 2, the gradation portion 23 is shown in a state in which the layer thickness increases toward the bottom, but this is a schematic representation of the dot density of the paint gradually increasing toward the bottom, and in reality, the thickness of the gradation portion 23 is formed approximately uniformly throughout. In addition to the dots being independent, some dots may overlap or be connected in the surface direction, and the thickness of the overlapping parts may be thicker than the other parts. Here, depending on the composition of the colored paint, it may be possible for part of the artificial marble to be slightly seen through the lower end of the gradation part 23.

[0020] Next, a method for forming a bathtub in this embodiment will be described. This molding is carried out using a molding die consisting of a convex die 30 and a concave die 31 as shown in FIG. A mixture of light-transmitting gel coat resin that forms the surface protective layer 22 is applied to the surface of the convex mold 30 with a release agent (not shown) being applied thereto. Next, a colored paint made by adding a colored toner to a clear paint is sprayed with a spray gun over the area from a position corresponding to the bottom surface of the flange to a position corresponding to the top surface of the step 13 to form the gradation section 23. This clear paint is sprayed so that the paint dot density gradually increases toward the bottom in Fig. 3, so that in the molded bathtub 10, the resin compound layer 20, i.e., the artificial marble, is not visible at the bottom end position of the gradation section 23. After applying the colored paint that forms the gradation portion 23, the surface protection layer 22, which corresponds to the lower region of the bathtub following the gradation portion 23, is sprayed with high dot density using, for example, the same colored paint as the material that forms the gradation portion 23. As a result, after the bathtub is molded, the artificial marble in the region below the gradation portion 23 is concealed by the concealing layer 24.

[0021] On the other hand, the inner surface of the concave mold 31 is coated with a release agent in the same manner as the convex mold 30, and then coated with a mixture of gel coat resins that form the back surface protective layer 25 that does not have optical transparency. After each layer applied to the convex mold 30 and the concave mold 31 has hardened, a predetermined amount of material M of the resin compound layer 20 is injected into the concave mold 31, and then the convex mold 30 is fitted into the concave mold 31, the molding die is clamped, and the material M is caused to flow within the internal space.

[0022] The mold is then turned upside down in order to allow air bubbles to gather on the back side of the product and prevent them from appearing on the surface of the product. The mold is then placed in a drying furnace and dried for a specified period of time, after which it is demolded and any necessary finishing work is carried out, thereby completing the bathtub 20, in which the appearance of artificial marble gradually fades from top to bottom in the upper inner surface area of ​​the peripheral wall 23.

[0023] Next, a specific embodiment of the bathtub of the present invention will be described.

[0024] Example 1 After applying a release agent to the convex mold, a transparent polyester gel coat resin, a curing agent, and a styrene monomer were mixed on the surface to form a surface protection layer, and the mixture was applied to a thickness of about 0.15 to 0.6 mm using a spray gun. For the gradation part, a colored paint made of transparent polyester gel coat resin with white toner added was adjusted in viscosity with styrene, and sprayed by adjusting the amount of air from the spray gun so that the dot diameter was about 0.3mm to 2mm and the height was about 0.1mm to 0.3mm. This spraying was done while visually checking that the dot density increased from top to bottom. After applying a release agent to the concave mold, a mixture of polyester-based white gel coat resin, a curing agent, and a styrene monomer was applied to the surface as a back surface protective layer with a spray gun to a thickness of about 0.15 mm to 0.6 mm. As a resin compound, 100 parts of polyester resin were mixed with 0.1 parts of white toner (50% product), 30 parts of white resin particles, 1 part of hardener, and 0.3 parts of accelerator, then poured into a concave mold, clamped to harden, dried, and demolded to obtain a bathtub with a thickness of 9 mm ± 3 mm. Most of the white resin particles are 0.3 mm to 2 mm in size, and the dot diameter is approximated to that size. When the surface of the bathtub was visually observed, it was possible to see that the appearance of the artificial marble faded seamlessly from top to bottom in the area from the position corresponding to the underside of the flange to the position corresponding to the step.

[0025] Example 2 This example differs from Example 1 in that a colored paint in which black toner is added to transparent polyester gel coat resin is used as the gradation part, and 100 parts of polyester resin is mixed with 0.1 part of carbon black toner (5% product), 30 parts of black resin particles, 3 parts of white resin particles, 1 part of hardener, and 0.3 parts of accelerator to form the resin compound layer, and the bathtub was molded in the same manner as Example 1. Here, the size of the black resin particles is mostly 0.3 mm to 2 mm, and the dot diameter is approximated to that size. The resulting bathtub surface had the same appearance as that of Example 1, except that it was primarily black.

[0026] Although the best configurations and methods for carrying out the present invention have been disclosed in the above description, the present invention is not limited thereto. That is, although the present invention has been particularly shown and described with respect to certain embodiments, those skilled in the art may make various modifications to the above-described embodiments without departing from the scope of the technical spirit and purpose of the present invention.

[0027] For example, in the above embodiment, a bathtub is shown as a concave molded product, but the present invention may be applied to other concave molded products such as a washbowl made of artificial marble, a sink, etc. In addition, the gradation portion is not limited to the case where the dot density increases from top to bottom, but also includes the case where the dot density increases from bottom to top depending on the molded product. Furthermore, it is not prohibited to change the dot density in the circumferential direction. Furthermore, in the above embodiment, the gradation portion is from the flange lower surface position to the step position, but this is not limited thereto. For example, it is possible to provide it on the entire surface side of the resin compound layer, and it is also possible to provide it on the entire surface side of a bathtub without a step. Furthermore, the dot diameter of the gradation portion may be approximately the size of the resin particles blended in the resin compound layer, and may be 2 mm or more. In short, the present invention is sufficient as long as it can express the state in which the appearance form of the artificial marble, such as the color and pattern, gradually changes in the molded product that expresses the appearance of the artificial marble. [Explanation of symbols]

[0028] 10...bathtub (concave molded product), 20...resin compound layer, 22...surface protection layer, 23...gradation portion, 24...concealing layer, 25...back protection layer

Claims

1. A concave molded article of artificial marble comprising a resin compound layer having an opening at the top and a light-transmitting surface protective layer provided on the inner surface of the resin compound layer, A concave molded product, characterized in that a gradation portion is provided along a predetermined direction between the resin compound layer and the surface protection layer.

2. The concave molded product according to claim 1, wherein the gradation portion is formed by spraying a colored paint in the form of dots, the colored paint being a clear paint to which a colored toner has been added, and the colored paint contains a colored toner of a similar color to the colored particles contained in the resin compound layer to form the gradation portion.

3. 3. The concave molded product according to claim 2, wherein the density of the dots increases gradually from the top to the bottom when the opening side is the top.

4. A method for producing a concave molded product made of artificial marble having a resin compound layer with an opening at the top and a light-transmitting surface protection layer located on the surface of the resin compound layer, using a mold including a convex mold and a concave mold, comprising: applying a gel coat resin mixture to the convex mold to form a surface protective layer; spraying a material for forming a gradation portion onto the surface protective layer; and after injecting the resin compound into the concave mold, clamping the mold to allow the resin compound to flow into the molding mold and form a concave shape. The method for manufacturing a concave molded product is characterized in that the gradation portion is formed by gradually increasing or decreasing the dot density by spraying colored paint along a predetermined direction.

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