JPS6282024A - Manufacture of molding - Google Patents

Abstract

PURPOSE:To provide long-sized molding which is superior in identify feeling, by a method wherein the inside of a split mold is fitted with an end of the molding whose other end is made into a desired form and a material for a terminal, to which high-frequency heating is applied and both are fused together. CONSTITUTION:A split mold 20 is so constituted that the same possesses a cavity 21 for a predetermined terminal molding and a cavity 22 for fitting of a molding terminal, both the cavities 21, 22 are communicated with each other and they are unified with a molding end part 12. The split mold 20 is constituted of a material whose dielectric loss is low, for example, silicon resin. On the other hand, an electrode plate 30 is arranged so that the cavity 21 for a terminal molded article is situated between both the electrode plates 30 and the cavity 22 for the molding end part is also arranged so that a part of the same is placed between the electrode plates 30. Then the electrode plate 30 is connected with a high-frequency generator 31. A material 13 for a terminal is fused to the molding terminal 12 along with molding of the material 13 through high frequency heating by fitting the cavity 21 for the terminal molded article with the material 13 for the terminal by fitting the cavity 22 for the molding end part with the other end part 12 of the molding.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a plastic molding that is fixed to the side surface of an automobile body and used for protection and decoration of the automobile body.

(Prior art) In recent years, most of the moldings used on the sides of automobile bodies for protection and decoration are made of plastic, and among them, plastic extrusion molded products made mainly of soft vinyl chloride resin are often used. . This is because the extrusion molded product is a long product with a constant cross-section, and it is easy to form a design line in a substantially straight line from the front to the rear of the vehicle body.

However, since the side of the vehicle body has openings such as doors, the extrusion molded product must be cut to a predetermined length such as the width of the door, and the cut end may pose a danger to the human body or prevent the door from opening or closing. It is necessary to finish the ends with a streamlined shape or a predetermined stepped shape so as not to cause any obstruction to the surface.

Therefore, conventionally, the end of the extrusion molded product cut to a predetermined length is placed in a split mold having a cavity of the desired end shape, and the end molded product is attached to the end of the extrusion molded product at the same time as the cap is formed by injection molding. things are being done.

However, this method has the drawback that the capping process described above must be performed on both cut ends of the molding body made of an extrusion molded product, which lengthens the process, and that the molding body is an extrusion molded product. Therefore,
It often has striations or the like on its surface in the longitudinal direction, and its appearance is different from that of the cap to which it is attached, which tends to create a sense of discomfort.

Therefore, in recent years, attempts have been made to manufacture the molding itself by injection molding. This is because the injection molding method is a method in which molten plastic is injected into a predetermined mold and molded, so the end portion can also be shaped at the same time as the molding.

(Problems to be Solved by the Invention) However, even in this injection molding method, since the molding is generally long, molding distortion tends to accumulate in the longitudinal direction. This molding strain is gradually released by subsequent thermal history, such as temperature and temperature, and the molding generally contracts. This shrinkage causes the mounting position to shift after the molding is mounted on a vehicle body, etc., and is a factor that may lead to damage to the mounting in some cases. Therefore, it is possible to forcibly release the molding strain by annealing the molding after injection molding, but the molding strain is not necessarily uniform, and the molding length after annealing varies, resulting in a product with a predetermined length being always obtained. However, there are some drawbacks. Therefore, the applicant of the present invention first molded a molding 10a having a predetermined shape at least at one end by injection molding, and after annealing, the other end of the molding 10a was further injection molded to form a predetermined terminal as shown in FIG. We proposed a molding production method in which the molded product is applied at the same time as molding. However, even with this method, the end molded product to be molded is smaller than the molding body to which it is attached. Therefore, it is impossible to melt the end portion of the molding body with the heat of the molten resin, which has the disadvantage that it is not uniform and a clear connection line appears between the end portion of the molding and the end molded product to be adhered. ing.

(Means for Solving the Problems) Therefore, the present invention aims to provide a novel method for manufacturing a molding having a predetermined terminal shape, which eliminates such drawbacks, and the gist thereof is as follows. The other end of the molding, at least one end of which has been shaped into a desired shape, and the terminal material are placed in a split mold having a cavity with a predetermined terminal shape, and the end and the terminal material are subjected to high-frequency heating. , a method of manufacturing a molding characterized by fusing the two together and shaping the molding into a predetermined cavity shape.

(Function) The molding end and the end material placed in a split mold having a cavity of a predetermined end shape are melted together by high frequency heating and are fused and integrated. At the same time, the integral body is shaped into a cavity shape in a fluid manner, resulting in a molding having a predetermined end shape. That is, a molding with a predetermined end shape can be produced without creating a connecting line. Embodiments of the present invention will be described below with reference to the drawings.

(Example) Fig. 1 is a cross-sectional view of the main part of the present invention in which the molding end and the terminal material are installed in a split mold, and Fig. 2 is a perspective view of the end after implementing the present invention. It is a diagram.

First, the molding body 10 is molded from a plastic raw material such as soft vinyl chloride resin into a long molded product having a predetermined end shape at one end 11. As this molding method, a normal injection molding method is suitable. This is because it is possible to give a desired end shape to at least one end 11 using an injection mold.

Note that the other end 12 of the molding body 10 is the same as the one end 1.
Although it may be shaped into a predetermined terminal shape as in 1, it is not necessary. The plastic raw materials to be used are preferably plastics that are easily heated by high-frequency dielectrics, which will be described later, and are appropriately selected from those with polar groups and large dielectric loss, such as soft vinyl chloride resin, and are used in combination. .

Next, the molding body 10 is heated to release molding distortion (internal distortion). Due to the release of this molding strain, the molding body 10 typically contracts to reduce its length in its longitudinal direction. This heat treatment is commonly called annealing, and the heating temperature and time are selected depending on the plastic raw material used and the shape of the molded product. Further, as the heating means, known means such as a heating furnace and infrared rays can be used. However, this heat treatment is not necessarily necessary; the same effect can be obtained by leaving the molded material for a certain period of time after molding.

Then, the length of the molding body 10 whose molding strain has been released is marked or cut to have a constant length from one end 11 having a predetermined end shape. After that, the other end 12 of this molding body lO is
The device is placed in a split mold 20 shown in the figure. As shown in the figure, this division 20 has a cavity 21 for predetermined end molding and a cavity 22 for a molding end device on its division surface, and a high frequency electrode plate 30 is mounted on the outer surface. The cavity 21 for the terminal molded product and the cavity 22 for the molding end are in communication as shown in the figure, and are made to be integrated with the molding end 12 when the terminal is molded. The split mold 20 is made of a material with low dielectric loss, such as plastic such as silicone resin or epoxy resin, ceramic, or glass. On the other hand, the electrode plate 30 is arranged such that the cavity 21 for the end molded product is located between both electrode plates 30, and the molding end cavity 22 is also arranged so as to sandwich a part thereof. Further, this electrode plate 30 is connected to a high frequency generator 31. 23 in the diagram
2 is a molding end positioning protrusion, and 24 is a flow path for a coolant or the like.

Then, the other end 12 of the molding is placed in the molding end cavity 22, and the terminal material 13 is placed in the terminal molded product cavity 21. Since this terminal material 13 is molded by high-frequency heating and fused to the molding end 12, which will be described later, it is made of plastic with a large dielectric loss, like the molding body 10, and is made of a plate or the like in advance into a predetermined shape. It is stamped or preformed from. It is usually made of the same or similar material as the molding body 10, for example, soft vinyl chloride resin. Note that a chemical foaming agent such as an azo compound such as azocabonamide or a nitroso compound such as dinitrosopentamethylenetetramine may be cross-dispersed in the terminal material 13 in advance in a non-foaming state or a very low foaming state. Then, with the split mold 20 closed as shown in FIG. 1, a high frequency voltage is applied between the electrode plates 30. Then, since the split mold 20 is made of a material with low dielectric loss, the high frequency current passes through the split mold 20. On the other hand, since the terminal material 13 and the molding end 12 that are included inside are made of materials with large dielectric loss as described above, it is difficult for them to be heated intensively as they absorb high frequency current. Become. At this time, since the storage cavity 21 of the terminal material 13 is entirely located between the electrode plates 30 as described above, the terminal material 13 is completely melted and the molding body 10 is completely melted.
The ends thereof, especially the ends 12 located between the electrode plates, are heated and melted toward the ends. and,
The terminal material 13 and the molding end 12 are fused in a molten state, and the melting causes a part of the terminal material 13 and the molding end 12 to flow into the terminal molded product cavity 21. It will be shaped. Therefore, the molding 14 after cooling has a predetermined end shape without a connecting line. In addition,
When the terminal material 13 contains a chemical foaming agent as described above, the foaming agent decomposes as the material 13 melts, and the volumetric expansion of the material 13 fills the terminal molded cavity 21. In this case, if the molding body 10 is also made of foam, a lighter molding can be obtained.

(Effects) As described above, the present invention is arranged such that the other end of the molding main body whose at least one end is shaped into a desired shape and the terminal material are placed in a split mold having a predetermined cavity. Since the molding material is welded and shaped by high-frequency heating, there is no need for connecting lines as in the conventional method, and a long molding with an excellent sense of unity can be provided. Furthermore, since the terminal molded product made of the terminal material is melt-fused together with the molding end, there is no risk that the terminal molded product will fall off.

Furthermore, even if the molding body is molded by injection molding or the like and has built-in molding distortion, by implementing the present invention after removing the distortion, a molding of a constant length with little dimensional change can be manufactured. , it is possible to provide a molding suitable for protecting and decorating the body of an automobile.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the main part of an embodiment of the present invention, Fig. 2 is a perspective view of the end of the molding obtained by the present invention, and Fig. 3 is a case in which the end molded product is applied at the same time as molding by conventional injection molding. It is a sectional view of the main part. Explanation of symbols 10: Molding body 12: Molding end

Claims (1)

[Claims] The other end of the molding main body, with at least one end shaped into a desired shape, and the terminal material are placed in a split mold having a predetermined cavity, and the end and the terminal material are subjected to high frequency heating to heat both ends. A method for manufacturing a molding, which comprises fusing and shaping into a predetermined cavity shape.