JPH0411270B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing plastic moldings.

(Prior Art) Plastic decorative moldings are used for the surfaces of side panels of automobiles, the edges of window frames and other parts, and the edges of furniture.

In recent years, there has been a demand for protective moldings with very thin walls due to the diversification of needs in, for example, the above-mentioned moldings for automobiles.

Normally, extrusion molded products are often used for this type of decorative molding from the viewpoint of efficiency and economy, but in the case of extrusion molding, the molded product is molded in a molten state immediately after being extruded from a die. There is a limit to how thin the wall can be made due to the handling of products, and for products with a width of 2 to 3 cm, the limit for wall thickness is approximately 4 to 5 mm. Obtaining molding was extremely difficult.

It has also been proposed to reduce the thickness by rolling or other means after extrusion, but this may result in uneven molding width, or the presence of scratches from rolling rolls on the surface, etc., resulting in poor appearance. Due to decorative issues, it cannot be implemented.

In addition to the above-mentioned extrusion molding, this type of molding can also be obtained by injection molding, etc., but there is always a demand for products that are more beautiful and have new concepts.

(Problem to be solved by the invention) This invention was proposed in view of the current situation, and its purpose is to create a decoration with a glossy glass-like clear surface on the top surface. It is an object of the present invention to provide a new method for obtaining beautiful plastic moldings with excellent properties, especially plastic moldings with a new concept having an extremely thin wall thickness that is difficult to produce using conventional extrusion molding.

Another object of the present invention is to provide a method that can easily, reliably, and efficiently obtain the above-mentioned novel molding with excellent decorative properties.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a plurality of thermosetting liquid plastics applied to the top surface of a plastic sheet substrate in which the edge of the liquid plastic casting part is formed into a sharp edge. The liquid plastic flows down from the nozzle onto the top surface of the substrate, and the plural strips of liquid plastic are cast in the direction of the surface and merged to form a single liquid plastic surface, which is then heated and hardened to form rounded corners on the top surface of the substrate. The idea is to integrally form a plastic decorative surface with an edge.

(Example) The present invention will be described below with reference to the accompanying drawings.

Figure 1 of the accompanying drawings is a partially omitted perspective view of a plastic molding obtained by the present invention, particularly a protective/decorative molding that is attached to the side panel of an automobile, and Figure 2 is a terminal view of the plastic molding. FIG. 3 is a cross-sectional view showing the side end portion of the base, FIG. 4 is a cross-sectional view showing the liquid plastic flowing down onto the upper surface of the base, and FIG. Each figure is a cross-sectional view showing a state in which multiple strips of liquid plastic are cast in the plane direction and merged to form a single liquid plastic surface, and FIG. 6 is a cross-sectional view showing a state in which the liquid plastic surface is heated and hardened. FIG. 7 is a sectional view showing a state in which liquid plastic is cast when it is flowed down from a single nozzle.

As shown in FIGS. 1 to 3, the plastic molding 10 obtained by the method of the present invention includes a base made of a plastic sheet strip 11, etc., and a thermosetting liquid plastic formed on the surface of the base. It consists of a decorative surface 20 consisting of a hardened portion of.

The plastic decorative surface 20 is a glossy, smooth, beautiful surface with a lens-like effect, and each of its edges 25, 26, 27 are formed with rounded corners.

In the figure, reference numeral 30 is an adhesive tape for attaching this decorative molding to the vehicle body, 31 is an adhesive,
32 is the protective paper.

The illustrated molding 10 is a 0.5 mm plastic sheet strip 11 with a 1.0 mm plastic decorative surface 20 formed thereon, resulting in a 0.4 mm thin molding.

In addition to the plastic sheet 11 made of vinyl chloride resin or the like in the embodiment, the base may be an extrusion molded or injection molded product of a suitable plastic, and may be colored to enhance its decorative effect, or its surface may be Printed decorations such as letters and patterns may be formed on the surface.

It goes without saying that the shape of the substrate can be arbitrary, but the edge of the substrate surface 15 on which the liquid plastic is cast may be, for example, the right-angled edge 1 shown in the figure.
It is composed of sharp edges like 9.

Next, the method of the present invention will be specifically explained with reference to FIG. 4 and the following figures.

FIG. 4 shows the plastic sheet substrate 1.
thermosetting liquid plastic 21 on the surface 15 of 1;
22 is shown flowing down from a plurality of nozzles 41 and 42.

The liquid plastics 21, 22 are allowed to flow down onto the upper surface 15 of the horizontally held substrate 11 at intervals and amounts most convenient for the casting and merging described below.

When the base body 11 is a long and thin piece, as shown in the figure,
It flows down in parallel along its longitudinal direction.

Liquid plastic 2 flowing down onto the upper surface 15 of the base
1 and 22 are then cast and merged as shown in the order of a, b, c, . . . in each figure of FIG.

That is, each strip of liquid plastic 21, 22
From the bead-shaped state a immediately after flowing down, the flow edge flows along the base surface 15 in the plane direction, and when it reaches the end extensions 16 and 17, it stops there due to surface tension b.

Liquid plastic with one end stopped by surface tension 2
1 and 22 flow to the opposite center side and merge with each other c. Merged liquid plastic 2
1 and 22, the surface tension of the integrated liquid instead of the individual surface tension of each flow causes a physical action to maintain a uniform surface, resulting in A single liquid plastic surface 23 with a uniform surface is formed d.

The liquid plastic surface 23 is formed in this way.
This is done by utilizing the natural flow of liquid and its surface tension. In particular, this invention utilizes the surface tension caused by the merging of multiple liquids in addition to the surface tension caused by the casting of multiple stripes of liquid, making it possible to form extremely thin liquid plastic surfaces. It is.

For comparison with the present invention, FIG. 7 shows a state in which liquid plastic is flowed down from a single nozzle onto a substrate, but in the case of a single liquid, as shown in the figure, There are limits to the range and thickness of the casting, and it is not possible to cast as widely and thinly as in the present invention, which involves merging multiple liquids.

Furthermore, by forming the edge of the substrate surface 15 on which the liquid plastic is cast into a sharp edge such as the right-angled edge 19, the liquid plastic forms a curved surface that bulges due to surface tension at the sharp edge. A decorative surface with rounded corners and beautiful edges can be formed.

Regarding the liquid plastic used in the present invention, this plastic is thermosetting and usually transparent. For example, a liquid polyurethane composition consisting of a polyol and a diisocyanate is a preferred material. these are,
An appropriate catalyst is used to accelerate or control the curing rate, and an antioxidant is used to improve the physical properties of the molded product such as heat resistance, light resistance, and weather resistance.
Auxiliary agents such as ultraviolet absorbers and light stabilizers are used in appropriate amounts.

Other useful liquid plastics include liquid acrylic resin compositions containing methyl methacrylate as a main component and epoxy resin compositions having epoxy groups in their molecules. Note that the liquid plastic may be colored by mixing a dye or the like.

After forming the liquid plastic surface 23, the liquid plastic is heated and hardened to integrate it with the liquid 11.

Heating is done using an infrared lamp 45 as shown in Figure 6.
In addition to being irradiated with infrared rays, it may also be introduced into a heating furnace. The heating temperature depends on the material and physical properties of the liquid plastic, but is approximately 50 to 80 degrees Celsius.
It would be about that.

(Effects) As shown and explained above, according to the method for manufacturing plastic molding of the present invention, thermosetting liquid plastic is applied to the upper surface of the plastic sheet base, where the edge of the liquid plastic casting part is formed into a sharp edge. The liquid plastic flows down onto the top surface of the substrate from a plurality of nozzles, and the plural strips of liquid plastic are cast in the direction of the surface and merged to form a single liquid plastic surface, and then heated and hardened to form corners on the top surface of the substrate. Since it is specially designed to form a decorative plastic surface with rounded edges in one piece, the surface tension of the liquid creates a glossy, glass-like clear surface on the top surface of the base plastic, if necessary. It has now become possible to easily, reliably, and efficiently obtain beautiful moldings with excellent decorative properties in which a plastic layer with an extremely thin wall thickness is formed.

[Brief explanation of drawings]

Figure 1 is a partially omitted perspective view of a plastic molding obtained by the present invention, particularly a protective/decorative molding that is attached to the side panel of an automobile, and Figure 2 shows its terminal part. Figure 3 is a cross-sectional view showing the side edge of the same cut in the width direction, Figure 4 is a cross-sectional view showing the state in which liquid plastic is flowing down onto the upper surface of the base, and Figure 5 is a cross-sectional view showing the side edges of the same. A cross-sectional view showing a state in which multiple strips of liquid plastic are cast in the plane direction and merged to form a single liquid plastic surface. FIG. 6 is a cross-sectional view showing a state in which the liquid plastic surface is heated and hardened. FIG. 1 is a sectional view showing a state in which liquid plastic is flowed down from a single nozzle; FIG. 10...Protective/decorative molding for automobiles,
11... Plastic sheet base, 16, 17...
Edge portion, 19... Right angle edge, 20... Plastic decorative surface, 21, 22... Liquid plastic, 2
3... Liquid plastic surface, 30... Adhesive tape, 41, 42... Nozzle, 45... Infrared lamp.

Claims (1)

[Claims] 1. On the upper surface of a plastic sheet substrate where the edges of the liquid plastic casting part are formed into sharp edges, a thermosetting liquid plastic is poured onto the upper surface of the substrate from a plurality of nozzles, and the plurality of strips of liquid plastic are cast in the surface direction. A plastic molding characterized in that a plastic decorative surface having rounded edges is integrally formed on the upper surface of the base by merging to form a single liquid plastic surface and then heating and curing the surface. Production method.