JP2530182B2 - Method for manufacturing molding with metallic appearance - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a molding used on a side surface of a vehicle body of an automobile or the like.

(Prior Art) Conventionally, the moldings that are mainly used for the protection of the vehicle body and the decoration on the side surface of the automobile are mainly made of plastics, and among them, those processed by extrusion molding of plastics are often used. . As described above, this molding is one of its main functions to impart a decorative aesthetic appearance to the vehicle body, and therefore it is generally colored in various colors in consideration of the color of the vehicle body.

On the other hand, in recent years, car bodies have been graded even within the same car model, and as one of the means, the car body color is made metallic to give a high-class feeling. Accordingly, it is desired that the molding used on the side surface of the vehicle body also has a metallic appearance. Therefore, in some parts, a plastic extruded product with the same metallic coating as the car body is used.

(Problems to be solved by the invention) However, although it is easy to obtain a metallic appearance by coating, as is well known, the coating efficiency of the coating during coating is extremely low, and the metallic coating is expensive and dusty. Therefore, there is a problem that the cost of molding increases significantly. In addition, a drying and baking process of the coating film is indispensable for coating, and there is a problem that the process becomes long and it is necessary to control so that foreign matters and the like do not adhere during the process. Furthermore, the coating film formed is at most 20-30μ
It is extremely thin and easily peels off due to a slight accident such as a vehicle contact.

On the other hand, it is possible to mix the metallic pigment into the transparent plastic raw material and mold it, but in the above-mentioned extrusion molding, it has to be molded into a predetermined shape by passing through a molding die, so However, there is a drawback in that even if plating is applied, scratches at the die exit cannot be avoided.
Also, even though the plastic raw material is in a molten state, it is not a liquid, so the surface of the molded product is a series of minute irregularities, the appearance is dull, and the metallic color tone is inadequate. .

(Means for Solving the Problems) Therefore, the applicant of the present invention has earnestly studied, and arrived at the present invention by paying attention to the fact that the main component of the metallic pigment is metal powder or the like and has a higher melting temperature than that of plastic. It is a thing. And the gist of the present invention is that in a method for producing a molding in which a plastic raw material is melted and extruded from the predetermined molding die into a predetermined cross-sectional shape, a metallic pigment is mixed into a transparent plastic raw material. Then, when the molding base material extruded from the molding die is still hot, the surface of the base material is blown to the predetermined surface of the base material by blowing hot air at a temperature higher than the melting temperature of the base material or lower than the melting temperature of the metallic pigment. Is re-melted to be smoothed and the metallic pigment present on the surface is partially exposed.

(Function) The metallic pigment is mixed in the transparent plastic raw material and kneaded in the extruder to be uniformly dispersed in the molten plastic. Then, in that state, it is extruded from the molding die. At this time, as is usual in extrusion molding, the temperature of the molded article molding substrate immediately after the die is set to a temperature slightly lower than the complete melting temperature of the plastic raw material so that the cross-sectional shape can be maintained. Therefore, the metallic pigment is present in the substrate covered with the molten transparent plastic. Therefore, when the surface of the base material is further heated with hot air having a temperature higher than the melting temperature of the resin constituting the base material and lower than the melting temperature of the metallic pigment, the surface of the base material is completely melted and liquefied to form a smooth transparent surface. As a result, the plastic covering the metallic pigment is melted, but the aluminum powder, which is the main component of the metallic pigment, is not melted, and the metallic pigment is partially exposed and scattered on the smooth surface. By cooling in this state, the surface of the molded product maintains a very smooth liquid surface and solidifies by exposing a part of the metallic pigment, so that the surface of the molded product becomes a glossy glossy surface. At the same time, the reflected light from the metallic pigment on the surface interferes with the reflected light from below the surface, and a fresh metallic appearance is exhibited. Further, by the melting and liquefaction of the surface due to the heating, the scratches that have been conventionally imparted by the molding die are also eliminated.

(Example) The present invention will be described based on examples. Fig. 1 is a perspective view of a main part showing a manufacturing process of a molding, Fig. 2 is a schematic view showing reflection in the molding, and Fig. 3 is a cross section of the molding. Here is an example.

First, as a transparent plastic raw material, a transparent soft vinyl chloride resin mixed with a metallic pigment, a desired colored pigment, and other stabilizers for vinyl chloride is used. It is preferable that the metallic pigment has a metal powder such as aluminum, bronze, or mica titanium as a main component, and the surface thereof is subjected to an antioxidant treatment. The colored pigment is for coloring the molding base material in a desired color, and is appropriately selected.

The soft vinyl chloride resin raw material mixed with the metallic pigment or the like is heated and kneaded by the extruder 10, and is pressed into the crosshead die 11 in a molten state. The crosshead die 11 is provided with a resin flow path and an outlet for extruding the molten resin into a predetermined shape at substantially right angles to the extrusion shaft. In the crosshead die shown in the figure, a through hole 12 communicating with the resin flow path is provided from the side opposite to the resin flow path outlet, and the through hole 12 has a core material.
When the core material 21 is inserted, the molten resin containing the metallic pigment is coated in a predetermined shape on the core material 21. The core material 21 is used to reinforce the molding base material 20 or to form a central portion of the molding base material, and various metal foils or plates or long products of plastic are used. When the core material 21 is made of plastic, another extruder head (not shown) is connected to the through hole of the crosshead, and the core material 21 is extruded and simultaneously coated with the molten resin containing the metallic pigment. You may do it. The core material 21 is not always necessary.

The molding base material 20 having a predetermined cross-sectional shape extruded from the die outlet is blown with hot air of 200 to 240 ° C. from the nozzle 30 provided adjacent to the die 11 when the base material 20 is still hot. The predetermined surface 22 of the base material 20 is heated and melted again. As a result, the scratches at the die outlet on the surface of the base material disappear, the surface is smoothed, and the metallic pigment 41 scattered on the surface of the base material is partially exposed as shown in FIG.
This is because the main component of the metallic pigment is a metal foil such as aluminum as a main component, the metal powder does not melt at the temperature of the hot air, and the surrounding base material constituent resin covering the metallic pigment 41 melts. . Moreover, as described above, the surface of the base material is re-melted, so that the surface of the base material becomes a liquid surface, and a glossy glossy surface is generated. In the figure, 42 is a colored pigment, and 43 is a colorless additive mixed in the substrate. Then, the base material 20 is slowly cooled and then taken off to be solidified while the surface smoothness and the like are maintained. Solidified molding base 20
As shown in the drawing, the product is taken up by a belt conveyor 50, and is cut or cut into a desired length to be used as it is or further with terminal processing and a fixing means such as a double-sided adhesive tape attached.

FIG. 3 is an example of a cross section of the molding M obtained according to the present invention. The outer surface of the plastic core material 21 is a coating layer (base material layer) of a transparent soft vinyl chloride resin containing a metallic pigment.
22 are provided. Reference numeral 23 is a decorative foil of a metal vapor deposition film attached in the longitudinal direction of the surface of the coating layer 22.

(Effect) As described above, the present invention extrudes a molding base material from a transparent plastic raw material containing a metallic pigment and melts the metallic pigment at a temperature not lower than the melting temperature of the resin constituting the base material while the base material is still hot. Since the base material surface is remelted at a temperature lower than the temperature, the base material surface is smoothed and the metallic pigment is partially exposed as shown in FIG. Therefore, in the light reflected from the molding, in addition to the reflected light from the surface and the inside of the base resin, scattered light, strong reflected light from the metallic pigment exposed on the surface is reflected in the eyes, and an extremely metallic feeling is felt.
Further, the metallic feeling is more strongly reflected because the surface of the base material is smoothed and becomes a glossy glossy surface.
On the other hand, even if a transparent plastic layer containing a metallic pigment is formed on the core material by extrusion coating, the thickness thereof is several hundred times or more the thickness of the coating film, and there is no fear of peeling or the like.
Further, due to the thickness thereof, reflected light from the inside is more reflected and a deep appearance can be obtained. On the contrary, by forming the metallic-like outer layer on the core material, the expensive metallic pigment can be used in the minimum necessary amount, and there is no fear that the coating efficiency as in coating will be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an essential part of the present invention, FIG. 2 is an enlarged cross-sectional view of the surface of the obtained molding base material, and FIG. 3 is a cross-sectional example of the molding.

Claims (2)

(57) [Claims] 1. A method for producing a molding in which a plastic raw material is melted and extruded from a predetermined molding die to obtain a predetermined cross-sectional shape. In the method, a transparent plastic raw material is mixed with a metallic pigment and extruded from the molding die. When the molding base material is still hot, the predetermined surface of the base material is heated to a temperature not lower than the melting temperature of the base material and lower than the melting temperature of the metallic pigment to remelt the surface and smooth the surface. A method for producing a molding having a metallic appearance, which comprises exposing a part of the metallic pigment present on the material surface. 2. The method for producing a molding having a metallic appearance according to claim 1, wherein a transparent plastic mixed with a metallic pigment is extrusion-coated on a core material to a predetermined thickness.