KR-20260067193-A - manufacturing method of plastic molded products having polyurethan double-layer formed on surface

Abstract

The present invention relates to a method for manufacturing a plastic molded article, and more specifically, to a method for manufacturing a plastic molded article having a polyurethane double molded layer formed on its surface. The present invention comprises a first injection step of forming a main body by injecting a base resin into a first cavity while the main body is supported by the main body in the first injection step, a second injection step of forming a first molding layer on the surface of the main body by injecting a polyurethane resin into a second cavity while the main body is supported by the main body in the main body in the main body in the second injection step, and a third injection step of forming a second molding layer on the surface of the first molding layer by injecting a polyurethane resin into a third cavity while the main body is supported by the main body in the main body in the second injection step.

Inventors

• 허원근
• 서창호
• 이준호

Assignees

• (주) 우성정공

Dates

Publication Date

20260512

Application Date

20241105

Claims (4)

1. A first injection step of forming a main body by joining a first movable mold to a fixed mold and injecting a base resin into a first cavity; A second injection step in which, after the first injection step, while the main body is supported by the fixed mold, a second movable mold is joined to the fixed mold and polyurethane resin is injected into the second cavity to form a first molding layer on the surface of the main body; A method for manufacturing a plastic molded article having a polyurethane double molded layer on its surface, characterized by including: a third injection step in which, after the second injection step, while the main body is supported by the fixed mold, a third movable mold is joined to the fixed mold and a polyurethane resin is injected into the third cavity to form a second molded layer on the surface of the first molded layer.
2. A method for manufacturing a plastic molded article having a polyurethane double molded layer on a surface, characterized by further including an interface forming step for forming an interface layer between the first molded layer and the second molded layer in claim 1.
3. A method for manufacturing a plastic molded article having a polyurethane double molded layer on a surface, wherein, in claim 2, the interface forming step is formed by applying a paint to the surface of the first molded layer.
4. A method for manufacturing a plastic molded article having a polyurethane double molding layer on a surface, characterized in that, in claim 1, an intaglio or relief pattern is formed on the surface of the first molding layer or the second molding layer.

Description

Manufacturing method of plastic molded products having polyurethane double-layer formed on surface The present invention relates to a method for manufacturing a plastic molded article, and more specifically, to a method for manufacturing a plastic molded article having a polyurethane double molded layer formed on its surface. Various types of plastic parts used in automobiles, home appliances, and the like, especially those exposed to the outside, are surface-treated for functionality or an aesthetic appearance. The surfaces of various automotive interior components, such as consoles, door trims, or armrests, are treated in various ways after injection molding to provide a luxurious image to the vehicle's interior and to offer a more comfortable atmosphere to passengers by imparting a soft touch to areas where physical contact with passengers is expected. As the most representative method of surface treatment, metal plating or paint application is used to treat the surface. However, this surface treatment method has the problem of reduced production efficiency because separate plating and painting facilities must be installed. In addition, there are problems such as the inability to form a thick surface layer and the difficulty in realizing various types of patterns. To address these issues, a technology for manufacturing automotive interior materials by bonding polyurethane foam to the surface of injection-molded parts is known. However, such materials have disadvantages, including increased costs due to the increased number of processes for attaching the polyurethane foam with adhesive, and environmentally harmful substances such as volatile organic compounds resulting from the use of adhesives. Therefore, there is a growing need for technological development regarding materials that can simplify the manufacturing process to lower product unit costs, enable application to standard vehicle models, and express the feel of premium materials. Accordingly, Korean registered patent No. 10-2327305 discloses a method for manufacturing a skin foam integrated armrest. The manufacturing method disclosed above forms polyurethane foam on the surface of a substrate by a double injection molding method. However, since this manufacturing method forms only a single layer on the surface of the substrate, there are limitations in achieving high quality and producing various patterns. FIG. 1 is a block diagram showing the process flow of a method for manufacturing a plastic molded article according to an example of the present invention, and FIG. 2 is a schematic diagram showing the manufacturing method of FIG. 1 in sequence, and Figure 3 is a schematic plan view of a fixed mold applied to the manufacturing method of Figure 1. Hereinafter, a method for manufacturing a plastic molded article having a polyurethane double molding layer on its surface according to a preferred embodiment of the present invention will be described in detail. Referring to FIGS. 1 to 3, a method for manufacturing a plastic molded article of the present invention is provided as an example and comprises: a first injection step in which a first movable mold (15) is formed by joining a fixed mold and injecting a base resin into a first cavity to form a main body (1); a second injection step in which, after the first injection step, while the main body (1) is supported by the fixed mold, a second movable mold (25) is joined by the fixed mold and injecting a polyurethane resin into a second cavity to form a first molding layer (3) on the surface of the main body (1); and a third injection step in which, after the second injection step, while the main body (1) is supported by the fixed mold, a third movable mold (35) is joined by the fixed mold and injecting a polyurethane resin into a third cavity to form a second molding layer (5) on the surface of the first molding layer (3). The above-described first, second, and third injections are performed in an injection device. An injection device for implementing the manufacturing method of the present invention includes a fixed mold and a movable mold that can be mated with the fixed mold. The movable mold may be positioned on the upper part of the fixed mold. Since the present invention involves injection in three stages, it consists of three fixed molds and three movable molds. The three fixed molds can be classified into a first fixed mold (10), a second fixed mold (20), and a third fixed mold (30). The three movable molds can also be classified into a first movable mold (15), a second movable mold (25), and a third movable mold (35). Three fixed molds (10)(20)(30) are installed on a 360° rotatable table (50) as shown in FIG. 3. The three fixed molds (10)(20)(30) can be arranged at 120° intervals. A core is provided on the upper part of each fixed mold (10)(20)(30). For convenience of explanation, the core provided in the first fixed mold (10) is referred to as the first core (11), the core provided in the s