JPH0280222A - Synthetic resin molding - Google Patents

Abstract

PURPOSE:To give a special appearance by employing resin having an appearance different from the resin constituting other part in the part facing to at least one surface as moldings of a laminate construction in harmonica-shaped hollow moldings in its molding cross-section. CONSTITUTION:A first extruder 21 extrudes polypropylene resin 15 being transparent for example in MFR. Whereas, a second extruder 22 extrudes polypropylene resin 16 of the MFR added with colored MB of 5wt.%. And, the discharging rate by the two extruders 21, 22 is 9 to 1 in its rate by weight. The colored resin 16 extruded from the second extruder 22 comes to be positioned on the upper side of a main conduit 26 by the resin conduit 25 of an adapter 24, and mixed to the upper side of the resin supplied from the extruder 21 in a mixing mold 23. Accordingly, as the resin is extruded through a mold 27, a panel is made to be a laminate construction, and thus, a colored resin layer 16 is formed on the upper part thereof.

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD 1 The present invention relates to a synthetic resin molded article, and more particularly to a hollow molded article having a harmonica-shaped cross section that is molded by extrusion through a mold having a special core.

[Summary of the invention M A hollow molded body with a harmonica-shaped cross section that is molded by extruding molten resin through a mold having a core with a slit-like groove formed at the tip, and the molded body is formed into a layered structure. , the resin in the portion facing at least one of the outer surfaces is made of colored resin, or the resin in the portion facing one or both surfaces is made of foamed resin, whereby the molded product is colored or given a special appearance. It was designed to give K. Conventional technology]

For example, as disclosed in Japanese Patent Publication No. 48-860, by extruding molten resin through a mold equipped with a core having a battledore-shaped cross section and a slit-like groove formed at the tip. , it becomes possible to obtain a hollow panel with a harmonica-shaped cross section. Such resins are used, for example, as materials for assembling boxes or as building materials. It was made by sea urchin. Problems to be solved by the K invention] Such a conventional hollow panel has a single layer structure,
Unemployed or simply colored in a single color. Therefore, such a panel may change its appearance.
I couldn't do it. The present invention has been made in view of these problems, and the object of the present invention is to provide a harmonica-shaped hollow panel-shaped molded product with a special appearance by creating a laminated structure. be. Means for Solving Problem K] The present invention provides a hollow body with a harmonica-shaped cross section that is molded by extruding molten resin through a mold having a core with a slit-like groove formed at the tip. In the formed body, the molded body has a laminated structure, and a resin that differs in appearance from the resin constituting the other part is used in the part facing at least one surface. Therefore, the synthetic resin molded body has a laminated structure, A resin different from the resin constituting the other parts will be used for at least one surface facing part, and this will color the hollow synthetic resin molded body or give it a special appearance. becomes possible. K Embodiment FIGS. 1 and 2 show a hollow synthetic resin molded body 10 according to a first embodiment of the present invention. This molded body 10 is molded from polypropylene and has a hollow interior. The hollow part 11 is defined by longitudinally extending ribs 12, thereby having a harmonica-like cross section. That is, the hollow molded body 10 is composed of a hollow panel having a harmonica-shaped cross section. The main body portion is not colored and is composed of a transparent first resin layer 15. The portion facing the outer surface of the molded body 10 is composed of a colored second resin layer 16, and has a two-layer structure. A colored layer 17 is formed by printing on the lower surface made of uncolored resin 15. That is, the upper surface of the panel 10 is given an appearance by a colored resin 16, whereas the lower surface of the panel 10 is given an appearance by a colored layer 17 formed by printing. FIG. 3 shows an apparatus for forming such a hollow panel 10, which apparatus is equipped with a pair of extruders 21, 22. The extruder 21 is for extruding the transparent first resin 15, and the extruder 21 is for extruding the transparent first resin 15.
The extruder 22 is for extruding the colored resin 16. These extruders 21 and 22 are the mixing mold 23
An adapter 24 as shown in FIG. 4 is provided between the second extruder 22 and the mold 23. The adapter 24 has a resin passage 25, and the outlet side of this passage 25 is offset from the inlet side. Note that instead of the mold 23 shown in FIG. 3 used together with the adapter 24, a multi-manifold type mold 23 as shown in FIG. 5 may be used. The second resin is supplied to the passage 35 above the mixing mold 23 through the supply port 25. A passage 36 in the center of the mold 23 is connected to the main resin passage 26, and two types of resin are mixed at the confluence with the passage 35. An extrusion mold 27 is disposed on the discharge side of the mixing mold 23 shown in FIG. A recess 28 is formed in the mold 27, and a core 29 is inserted into the recess 28 with a pair of pins 3o,
31. Furthermore, the core 29 is provided with a slit-shaped groove 32 on its front end side, and spaces 33 and 34 are formed above and below the core 29, respectively (see FIG. 6). In the above configuration, the first extruder 2
From No. 1, for example, a transparent polypropylene resin having an MFR of 1.5 is extruded. On the other hand, the second extruder 22 has an MFR of 1 with 5% by weight of color MB added.
．． 5. Extrude the polypropylene resin. That is, the second extruder 22 extrudes colored polypropylene resin. Further, the discharge amounts by the two extruders 21 and 22 are set at a weight ratio of 9:1. Second extruder 22
The colored resin 16 extruded from the resin passage 25 of the adapter 24 comes to be located above the main passage 26, and is mixed above the resin supplied from the extruder 21 in the mixing mold 23. Therefore, when such resin is extruded through the mold 27, the panel 10 forms a laminated structure as shown in FIGS. 1 and 2, and
A colored resin layer 16 will be formed on the upper part. Moreover, as the molten polypropylene is extruded while passing through the mold 27, the upper and lower gaps 33 and 34 of the core 29 and the slit-shaped groove 32 on the front end side of the core 29 are formed.
As a result, a laminate 10 consisting of harmonica-shaped hollow panels as shown in FIG. 1 is obtained. In this way, in this embodiment, a two-layer sheet 10 is formed using two types of resins 15 and 16 using multilayer molding technology.
I try to mold it. Moreover, in this case,
The surface layer is colored with colored resin 16, and transparent resin 15 is used for the middle and lower parts. Furthermore, the lower surface of the panel 10 is printed in a color different from the color of the second resin layer 16. Therefore, with such a structure, the printed colored layer 17 appears to stand out compared to the case of printing on a single-layer, single-color sheet, resulting in a brighter color finish. Furthermore, in the case of two colors, since the outer and inner surfaces of the panel 10 are different in color, the display effect is enhanced. Therefore, for example, by classifying the outer surface color into one type and the inner surface color into several types, it becomes possible to differentiate the boxes assembled with such panels 10. Furthermore, when light-shielding properties are required, it is possible to use a panel 10 whose portion facing the inside of the box is black, and to improve the image by applying another color to the outer surface. Next, a second embodiment will be explained with reference to FIGS. 7 to 10. This example uses ordinary polypropylene resin 1 in the middle.
5 is used, and foamed resin 16 is used on both sides. As shown in FIG. 8, the adapter 24 connected between the second extruder 22 and the mixing mold 23 shown in FIG. It has become a book. Also in this case, instead of the combination of the mold 23 and the adapter 24, a multi-manifold type mold 23 as shown in FIG. 9 may be used. The resin supply port 25 of this mold 23 is communicated with upper and lower passages 35. On the other hand, the resin supply port 26 through which the first resin is supplied is communicated with the central resin passage 36, so that the two types of resin are mixed at the confluence with the resin passage 35. It has become. Inside the extrusion mold 27, a core 29 is used, which has a battledore-shaped cross section similar to that of the first embodiment, and has a slit-shaped groove 32 at the tip. As shown, a hollow panel 10 is obtained which has a three-layer structure, the upper and lower surfaces are made of foamed resin 16, the middle part is made of transparent resin 15, and has a harmonica-shaped cross section. From the extruder 21 in Fig. 7, the MFR is 1.5.
The second extruder 22 extrudes a polypropylene resin having an MFR of 1.5 to which 2% by weight of foaming material has been added. Moreover, in this example, the weight ratio of the first resin 15 by the extruder 21 and the second resin 16 by the extruder 22 is 7:3. In addition, as shown in FIG. 10, a foamed resin layer 1 is provided on both sides.
6, the foamed resin layer 16 may be formed only on one side, and the first resin layer 15 may be exposed on the other side. As described above, the hollow panel 10 according to this embodiment has at least one surface formed of the foamed resin layer 16. By providing the foamed resin layer 16 on the surface, it becomes possible to obtain the panel 10 with pearl-like luster. Moreover, since the intermediate core portion is made of the conventional transparent synthetic resin 15, its strength is not impaired. Furthermore, when printing is performed on the surface of the foamed resin layer 16, the foamed resin layer 16 will play a role like a cushion, and the surface will easily become uneven.
The printing ink is applied uniformly to both the areas that touch the core 15 and the areas that do not touch the center core 15, thereby making it possible to perform good printing. (Effects of the Invention) As described above, the present invention is a molded article having a laminated structure, and a resin having a different appearance from the resin constituting the pond portion is used in the portion facing at least one surface. According to such a configuration, it is possible to color the molded product or to give it a special appearance by using the resin in the portion that does not constitute one element of the laminated structure and faces the outer surface.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a hollow molded body according to a first embodiment of the present invention;
Fig. 2 is a perspective view of the same external appearance, Fig. 3 is a side sectional view of a molding device for forming a hollow molded body, Fig. 4 is a longitudinal sectional view of the same adapter,
Fig. 5 is a longitudinal sectional view of the mixing mold, Fig. 6 is an enlarged front view of the main parts of the extrusion mold, and Fig. 7 is the main part of the apparatus for molding the molded product of the second embodiment. 8 is a longitudinal sectional view of the same adapter, FIG. 9 is a longitudinal sectional view of the mixing mold, 1st
Figure 0 is an enlarged sectional view of a hollow molded body obtained by this apparatus. The names of the main parts in the drawings are as follows. 10 Hollow formed body 11 Hollow portion 12 Rib 15 First resin layer 16 17 Second resin layer Colored layer

Claims (1)

[Claims] 1. A hollow molded body with a harmonica-shaped cross section that is molded by extruding molten resin through a mold having a core with a slit-like groove formed at the tip, and a laminated molded body; A synthetic resin molded article characterized in that a resin having a different appearance from the resin constituting the other portion is used in a portion facing at least one surface.