JPH0323918A - Molding method - Google Patents

Abstract

PURPOSE:To form a pattern together with at the time of molding without a complicated device or mold by having a second resin raw material contained in a first resin raw material, injecting the raw material into a cavity in the mold, having the size of difference in spaces of the cavity in the direction almost crossing the flowing direction of resin and guiding the second resin to larger spaces selectively. CONSTITUTION:A first resin passes through a small aperture 26 on the outer peripheral side of a torpedo 13 and also passes through a resin path 15 to be injected into a mold 16. A second colored resin is pressurized by a plunger 22, fed into a central aperture 25 of the torpedo 13, and the first resin and the second resin are mixed in the layer at an outlet section. Large and small space sections are formed in a cavity 20 alternatly in a manner of crossing the flowing direction of resin. The second resin 33 fed later is flowed concentratively particularly in a rib section 31 because of the difference of flows to form a stripe pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a molding method using a resin, and particularly to a molding method in which a molten resin raw material is forced out into a cavity in a mold and shaped.

K Outline of the Invention'' In addition to creating a difference in the gap between the cavities in the direction substantially perpendicular to the flow direction of the resin in the cavity in the mold, two types of resin raw materials are disposed in the mold to control the resin flow. This difference is used to selectively guide the second resin raw material into the gap between the cavities, thereby forming, for example, a striped pattern on the molded product. be.

KPrior Art 1 For example, when forming an opaque pattern of a predetermined color on a transparent synthetic resin molding, a two-color or pattern method has conventionally been used. That is, using a two-color molding machine, first, the first transparent resin is poured out, and then the mold is turned over and a certain resin is cut out from the colored raw material into the cavity formed, thereby forming the rib portion. It was designed to form a striped pattern.

2. Another method for forming a striped pattern on a transparent resin is to print the pattern in stripes on the surface of a transparent synthetic resin molded body. In this case, a striped pattern is formed in the height direction by a curved surface printing method on the body of a cup-shaped container that is indexed or shaped from transparent resin, for example.

However, depending on the shape of the molded product, printing may not be possible.

The present invention has been made in view of these problems, and it does not make the molding equipment or mold complicated, and also allows the pattern to be added to the shape at the same time without having to form the pattern in a separate process after molding. The purpose of this is to provide a method of precepts that can be formed.

Problems to be solved by the invention K: Forming a pattern using the first two-color molding method requires the use of a two-color molding machine, which makes the molding machine not only large but also expensive. . Furthermore, since a complicated mold is required, the cost of the mold also increases. Furthermore, since the cycle time of the preform becomes long, there is a drawback that the molding cost of the product also increases.

On the other hand, in the method of forming the striped pattern by printing on the cup, the cup is shaped in the first step and then printed in the second step. Therefore, there is a drawback that the number of steps increases. In addition, the present invention provides a means for solving the K problem by using the method of printing a pattern or a method of printing a curved surface. The cavity in the mold is indexed, and the gap between the cavities is made to have a difference in a direction substantially orthogonal to the flow direction of the resin in the cavity in the mold, and the second The resin is selectively guided to a portion with a large gap in the cavity.

(K effect) Therefore, if the shape of the cavity is set so that ribs are formed on the outer surface of the molded body along the flow direction of the resin, there will be a difference in the gap between the cavities in the direction almost perpendicular to the flow direction of the resin. It becomes possible to have

This difference in gap makes it possible to selectively guide the second resin to the rib portion of the precept-shaped body using the flow of the resin, and this second resin causes the precept-shaped body to follow the ribs. This allows a striped pattern to be formed.

K Embodiment 1 FIG. 4 does not show an apparatus used in a method of ceremonial injection according to an embodiment of the present invention, and this apparatus is equipped with a main injection device 10 for injecting a first resin. .

The main sword mount device 10 is composed of a cylinder, into which a screw 11 is rotatably fitted. The leading end side of the main injection device 10 is provided with a connecting tool 12, and a tortoe bead 13 is held within this connecting tool 12. A cap 14 is attached to the connector 12 so as to be connected to the tip of the toe bead 13, and a resin passage 15 is formed in the center of the cap 14. Resin passage 15
is connected to the gate 17 of the mold 16.

A small plunger device 20 is attached to the upper part of the connector 12 of the main indexing device 10, and this small plunger device 20 is equipped with screws 1 to 21. A plunger 22 is fixed to the piston 21.

Further, this small plunger device 20 is equipped with a hopper 23, and this hopper 23 supplies the second resin to the resin passage 2.
I try to supply it through 4.

In the above configuration, the main injection device 10 pressurizes and extrudes the first resin. This resin passes through the small hole 26 on the outer peripheral side of the toe bead 13 of the connector 12, passes through the resin passage 15 of the base 14, and is indexed to the gate 17 of the mold 16. On the other hand, the colored second resin is supplied from the hopper 23 of the small plunger device 20 through the resin passage 24 and is pressurized by the plunger 22 which is pressed by the piston 21. 25. The first and second resins are then mixed together in a layered manner at the exit portion of the tortobead 13.

5 and 6 show the first resin 32 and the second resin 33.
As shown in FIGS. 5 and 6, in the resin passage 15 and the gate 17, the first resin 32 is first supplied, and a little later, the first resin 32 is supplied from the center hole 25 of the toe bead 13. A second resin 33 is extracted,
It is encapsulated in the center of the first resin 32.

These two types of resins 32 and 33 are then poured into the cavity 29 of the mold 16 to form a cup-shaped body 30 as shown in FIGS. 3A to 3C. In this case, the two types of resin enter the cavity 29 from the center side of the bottom of the cup 30. And as shown in Figure 3A,
The leading transparent first resin 32 spreads into the cavity at the bottom of the cup 30 and extends into the barrel. Then, a little later, the second resin 33
will be ejected into the cavity 29.

At the bottom of the cup 30, the two types of resins 32 and 33 both expand in the radial direction.

As shown in an enlarged view in FIG. 2, the cavity 29 has a wide gap for shaping the ribs 31 of the molded body 30, so the body part of the cup-shaped molded body 30 is When the resin flows for shaping, portions with large gaps and portions with narrow gaps are alternately formed in the cavity 29 so as to be substantially perpendicular to the flow direction. A second resin 33 is supplied later than the first resin 32.
Due to the difference in flow between the first resin 32 and the first resin 32, as shown in FIGS.
The flow will be concentrated in this part.

Therefore, a striped pattern extending in the vertical direction is formed on the rib 31 portion of the cup-shaped molded body 30 by the colored second resin 33. Note that on the bottom side of the cup-shaped body 30, parts other than the ribs 31 are also colored by the surplus second resin 33.

In particular, the reason why the second resin 33 selectively flows into the portions with large gaps in the cavity is considered to be due to the following reason. As shown in FIG. 5, the second resin 33 is supplied slightly later than the first resin 32. As shown in FIG. 3A, the leading first resin 32 flows slightly ahead of the gap in the large part of the cavity 29 while also filling the narrow part of the gap. The preceding first resin 32 will gradually solidify on the contact surface of the mold. However, in the wide gap for forming the ribs 31, although the portion in contact with the mold solidifies, the inside remains in a fluid state because solidification is delayed. Therefore, the second resin 33 that is press-fitted thereafter flows intensively into the wide gap area where it is not solidified and easily flows, that is, into the rib 31 area. In this way, a pattern is formed on the rib 31 portion by the second resin 33 that is later expelled.

The first resin may be a highly transparent resin such as polybrobylene, polystyrene, polyethylene, polycarbonate, polyethylene terephthalate, or polyvinyl chloride. Further, as the second resin, pigment,
It may be a resin mixed with a dye, a fluorescent dye, or the like. The layer ratio is preferably about 85% to 15% of the main material and coloring raw material. Note that a maximum of about 50% of a coloring material can be mixed. Further, the mixing ratio of pigments, dyes, fluorescent dyes, etc. in the appetizer material may be about 3% to the main material, but it is possible to mix up to 40%. As is clear from FIG. 2, the pigments, dyes, fluorescent dyes, etc. mixed in the coloring material are covered by the transparent resin material and are not exposed to the outside. Therefore, even if drinks or foods are filled into such containers, no hygienic problems arise.

In this way, the small plunger device 20 is attached to the connector 12 of the main ejection device 10 shown in FIG. A tobead 13 is incorporated in the part to make it possible to change the layer structure of the main raw material 32 and the auxiliary raw material 33. Then, a rib 31 is placed on a cup-shaped body 30 as shown in FIG.
If this is done, a sliver-like pattern will be formed by the opaque second resin 33 containing the coloring raw material by utilizing the difference in resin flow in the chest area.

This method enables high-cycle molding due to simultaneous index molding of two types of resins 32 and 33, thereby making it possible to reduce the cost of the molded product. Furthermore, since the injection device and the mold can be made small and simple, the cost of the device or equipment can be reduced. Furthermore, since it can be formed into a certain shape in one process, production efficiency is high, and the equipment can be downsized, the installation space is extremely small.

K Application Example Blade Although the present invention has been described above with reference to the illustrated embodiment, the present invention is not limited to the above embodiment, and various modifications can be made based on the technical idea of the present invention. For example, by changing the shape of the ribs formed on the outer surface of the precept-shaped body, a molded product having a twisted pattern, letters, pictures, etc. can be obtained. In addition, if a resin that changes color depending on temperature changes, that is, a thermosensitive resin is used as the second resin 33, a cup-shaped molded body that generates a strip-like pattern by placing the contents inside the molded body can be created. It becomes possible to obtain.

K Effects of the Invention As described above, the present invention provides a gap between the cavities in a mold in a direction substantially perpendicular to the flow direction of the resin, and utilizes the difference in resin flow to create a second gap. The resin is selectively introduced into the gap between the cavities. Therefore, by simultaneous molding, it becomes possible to form various patterns such as stripes using the auxiliary raw material mixed into the main raw material, and it becomes possible to mold a molded product with a pattern shifted to the right at a low cost.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a cup-shaped molded body formed by a method according to an embodiment of the present invention, and FIG. FIG. 3 is an external perspective view of a cup-shaped body showing the state of resin flow, FIG. 4 is a vertical sectional view of the overall structure of the shaping device, and FIG.
The figure is a sectional view showing the flow state of two types of resin in the resin passage, and FIG. 6 is a sectional view taken along the line Vl to Vl in FIG. 5. The names of the main parts in the drawings are as follows. 1 0 ・ 1 2 ・ 1 3 ・ 1 5 ・ 1 6 ・ 20 ・ 2 2 ・ 29 ・ 30 ・ 31 ・ 3 2 ・ 3 2 ・ ・Main setting device, connecting tool, torbead, resin passage, mold, small size Plunger device・Plunger・Cavity・Cup・Rib・First resin・Second resin

Claims (1)

[Claims] 1. The second resin raw material is encapsulated in the first resin raw material and injected into the cavity in the mold, and the gap between the cavities in the mold is substantially perpendicular to the flow direction of the resin. A molding method characterized in that the second resin is selectively guided to a portion of the cavity with a large gap by making use of a difference in resin flow.