JPH0446734B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for forming a multi-material blow-molded product having a drawn portion for use in floor console boxes of automobiles and other arbitrary applications.

``Prior Art'' Blow molding has long been a method of molding resin parts, and it has become possible to mold simple containers with multiple layers of walls. However, in order to coordinate interior and exterior parts, when molding a single resin part from two or more types of materials with different colors or hardnesses, molded products with drawn parts are particularly important. In order to mold, in the conventional blow molding method, the boundary line of the mating part does not pass uniformly, so
There were problems with the appearance of the molded product, which was difficult to deal with using conventional blow molding methods.

"Problems to be Solved by the Invention" The present invention was made to solve the above-mentioned problems, and provides a method for blow-molding a multi-material molded product having a drawn part and forming a double wall with a good appearance. The purpose is to provide a method.

"Means for Solving the Problem" For the above purpose, according to the present invention, a U-shaped groove is provided in the middle of the side surface facing inward all around the circumference, and different materials are formed using the groove as a boundary. A first step of molding the divided hollow box body by blow molding, and further blow molding so that a large part of one side having a drawn portion with the U-shaped groove as a boundary is fitted into the other side. and a second step of molding a double-walled container.

"Operation" According to the above configuration, since the boundaries of different materials are located in the U-shaped groove, even if the boundary line of the mating part is distorted so as to be drawn to one side with the drawn part during blow molding, The boundary line falls within the U-shaped groove.

"Embodiment" According to the first embodiment of the present invention, the U-shaped groove is partially heated and pressurized from both sides of the molded product, so that both side walls of the U-shaped groove are heated. A method of forming a crimped multi-material blow molded article is provided. According to this aspect, since the inside of the U-shaped groove is hidden from the outside and no disturbance of the boundary line is seen, there is an advantage that the appearance of the molded product is further improved.

According to a second aspect of the invention, the pressure bonding is performed using an adhesive. According to this aspect, there is an advantage that the strength of the portion where the U-shaped groove is crimped is increased.

``Example'' Next, the present invention will be described with reference to an example of a floor console box with respect to a specific structure shown in the drawings.

As shown in FIG. 1, the final molded product, the floor console box 1, consists of a first hollow box 2 and a second hollow box 3 made of materials of different colors. The hollow box body 2 has a deep drawn part 21 and a shallow drawn part 22. A U-shaped groove 4 is provided between the first hollow box body 2 and the second hollow box body 3.

FIG. 2 is a sectional view taken along the - line in FIG. 1, and two types of materials having different colors for the hollow box body 2 and the hollow box body 3 are mixed in the U-shaped groove 4. Second
The two-dot chain line in the figure indicates the shape during blow molding, and is cut after blow molding. The U-shaped groove 4 may be left in the same shape as it was during blow molding, but in order to further improve the appearance, it is preferable to perform a concealing treatment. Figure 3 a, b
3A and 3B show two examples of methods for concealing the part where materials are mixed in the U-shaped groove 4 to improve its appearance.
A method may be used to narrow the entrance of the groove 4 by applying pressure to the hollow boxes 2 and 3 from both upper and lower sides while the entrance of the groove 4 is partially heated. A method of compressing both side walls of the U-shaped groove 4 by applying pressure to the console box 1 from both upper and lower sides of the hollow boxes 2 and 3 while the inside of the U-shaped groove 4 is partially heated so that the inside of the U-shaped groove 4 is partially heated. may be taken.
According to the method shown in FIG. 3b, the inside of the U-shaped groove 4 is completely hidden from the outside, so that the appearance is further improved. In addition, when performing the processing method shown in FIG. 3b, if the adhesive 5 is interposed between both side walls of the U-shaped groove 4, the both side walls are firmly joined, and the strength of the crimped portion is improved.

FIG. 4 shows the blow molding process for forming the hollow boxes 2, 3. For blow molding, a thermoplastic resin with good flow is heated and melted, and split molds 6, 7,
8, air is blown into the thermoplastic resin by an air blow nozzle (not shown) inside the molds 6, 7, and 8 to expand the resin.
Shape it in close contact with 7 and 8. During the blow molding, in the cross section where the deep drawn portion 21 exists,
Although the boundary line 41 is inevitably drawn toward the deep drawn portion 21 side and is distorted to the left in FIG. 4 compared to the boundary line 41 in the cross section where the shallow drawn portion 22 (not shown in FIG. 4) exists, By appropriately setting the width of the groove 4, the boundary line 41 can be accommodated within the U-shaped groove 4. As shown in FIG. 4, when the hollow boxes 2 and 3 have been completely molded by blow molding in the previous step, the vertical width of the hollow box 3 on the right side of the figure is the same as that of the hollow box body 3 on the left side. is larger than the top and bottom width. Further, the U-shaped groove 4 is formed between the split molds 7 and 8.

Next, in the final step, as shown in FIG. 5, a split mold 9 having a protrusion 91 is used, and after heating the hollow box 2 to give it fluidity, the movable mold 9 is used. Pressure is applied from the left side of the figure, and the air blow nozzle 10 is inserted between the hollow boxes 2 and 3.
Blow molding is performed by sucking air into the final double-walled shape. After the final product is molded as a two-color air blow molded product in this manner, the console box 1 is manufactured as described above by cutting the bottom of the wide hollow box body 3 as shown in FIG.

"Other Examples" In the above examples, the floor console box was manufactured as a two-color blow molded product, but
A double-walled container with a constricted portion can be formed in a similar manner. Further, the present invention is not limited to two-color blow-molded products, but can also be applied to multi-colored molded products made of multiple materials, and can be similarly applied to multiple materials having different hardness, strength, and other properties. It is possible.

"Effects" As described above, since the method of the present invention has the above configuration, it has the excellent effect of being able to blow mold a multi-material molded product having a drawn part and forming a double wall with a good appearance. There is.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a floor console box showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Figs. 3 a and b are two examples of methods for processing U-shaped grooves. Figure 4 is a cross-sectional view showing the state in which the hollow box body has been formed by blow molding in the previous step, and Figure 5 is the cross-sectional view showing the state in which the hollow box body has been formed into the final double wall shape by blow molding. It is a sectional view showing a state. 1...Floor console box, 2,3...
Hollow box body, 4... U-shaped groove, 5... Adhesive, 21
...Deep drawing part, 22...Shallow drawing part.

Claims (1)

[Scope of Claims] 1. A hollow box body which is provided with a U-shaped groove in the middle of the side surface facing inward all around the circumference and is divided into different materials using the groove as a boundary, is formed by blow molding. One step, and a second step of blow molding so that a large part of one side with a constricted part with the U-shaped groove as a boundary is fitted into the other side to form a double-walled container. A method for molding a multi-material blow molded product, characterized by performing the following steps. 2. The plurality of parts according to claim 1, wherein the U-shaped groove is pressurized from both sides of the molded product in a partially heated state, so that both side walls of the U-shaped groove are crimped. Method of forming material blow molded products. 3. The method for molding a multi-material blow molded product according to claim 2, wherein the pressure bonding is performed using an adhesive.