JPH0623794A - Two-color molding method and injection molding device for plastic article - Google Patents

Abstract

PURPOSE:To obtain a two-color plastic article molding method in which two color resins ideally flow and a two-color molding mode can be easily changed over to a single-color molding mode. CONSTITUTION:Heating cylinders 15a, 15b separately melting two color thermoplastic resins are disposed approximately in parallel to each other. A manifold member 60 is detachably mounted on the heating cylinders 15a, 15b. Resin receiving ports 80a, 80b are disposed correspondingly to injection ports 50a, 50b of the heating cylinders 15a, 15b. A two-color plastic article is molded using an injection molding device, in which the resin injection ports 50a, 50b are disposed correspondingly to the resin receiving ports 80a, 80b provided on runners 11a, 11b of a mold 100, and resin paths connecting the resin receiving ports 80a, 80b to the resin injection ports 50a, 50b are provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a two-color forming method and injection molding apparatus for plastic products.

[0002]

BACKGROUND OF THE INVENTION Plastic containers, which are widely used as containers for storing or transporting products such as foods, are color-coded in the left and right directions, so that the direction of the container can be visually recognized. There are some that can be identified.

By the way, when such a two-color container is integrally molded by injection molding, in order to supply the two-color resins into the cavity of the mold, two injections of the resins of different colors are performed. Equipment is required.

Generally, in performing such two-color molding, when the cylinders of these injection devices are arranged in parallel,
Since the injection device is large, conventionally, in order to introduce the two-color resin injected from the nozzle of the injection device arranged in this way into the cavity, sprue is provided on each of the left and right side surfaces of the mold, The sprue end was in contact with the nozzle end of the injection device.

When the sprues are projected on the left and right side surfaces of the mold in this manner, when the two injection devices for two-color molding are switched to the one for single-color molding and used, the mold is disassembled once. However, the sprue and the like must be replaced with monochromatic ones and the mold must be installed again, which causes a problem of poor workability.

In view of such a point, Japanese Patent Laid-Open No. 60-195
As in the conventional example of FIG. 4 described in Japanese Patent Publication No. 15, the cylinders of the two injection devices are arranged obliquely with respect to the moving direction of the mold so that they intersect each other on the extension line, and the vicinity of this intersection In some cases, one runner block 18 in which resin passages for guiding two color resins into the mold are collectively formed is provided. According to the molding method using such an injection device, the installation space near the mold can be reduced,
Moreover, the length of the runner can be shortened.

However, such a method has the following problems. That is, the injection devices 15a, 1
Although the cylinders of 5b are arranged in such a manner that they intersect each other on the extension line, the end surface of the runner block 18 arranged in the fixed base 17 is formed at a right angle to the moving direction of the mold. There is a problem that the nozzles 13a and 13b and the resin passages 12a and 12b formed in the runner block 18 are poorly in contact with each other, which causes turbulence in the resin flow and, in some cases, resin leakage. .

Two injection devices 15 for two-color molding
When switching a and 15b to the one for mono-color molding, once disassemble the mold, replace the runner block etc. provided in the recess of the mold with the one for mono-color and re-mold. Since it had to be installed, workability was poor, and further improvements were desired.

[0009]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a two-color molding method for plastic products, in which the flow of two-color resin is good and the two-color molding can be easily switched from single-color molding to single-color molding. It is an object of the present invention to provide a molding device used therefor.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, a two-color molding method for a plastic product according to the present invention is equipped with two heating cylinders for respectively melting thermoplastic resins colored differently from each other. A plastic product in which different color resins injected from the heating cylinder are guided to the mold runner, these resins are supplied to the cavity, and these resins are merged in the cavity for integral molding. In the two-color molding method, the heating cylinders are arranged so as to be substantially parallel to each other, and a manifold member is detachably arranged in the heating cylinder, and the manifold member is attached to the manifold member. The resin receiving port is provided at a position corresponding to the injection port, and the resin injection port is provided at a position corresponding to the resin receiving port provided on the runner of the mold. In addition, the present invention is characterized by using an injection molding device provided with a resin passage that connects the resin receiving port and the resin injection port.

In a preferred embodiment of the present invention,
The manifold member is provided with two resin passages that connect the resin receiving port and the resin injection port,
In addition, these two resin passages are formed closer to each other on the runner side of the die than on the cylinder side.

The injection molding apparatus according to the present invention is equipped with two heating cylinders for melting the thermoplastic resins separately,
Resin injection from these heating cylinders is guided to the mold runner, these resins are supplied from the runner to the cavity, and these resins are joined together in the cavity to form a plastic product. In the apparatus, the heating cylinders are arranged so as to be substantially parallel to each other, and a manifold member is detachably arranged in the heating cylinder, and the manifold member corresponds to the injection port of the heating cylinder. Is provided with a resin receiving port, a resin injection port is provided at a position corresponding to the resin receiving port provided on the runner of the mold, and a resin passage is provided for communicating the resin receiving port with the resin injection port. It is characterized by being.

In a preferred embodiment of the present invention,
The manifold member is provided with two resin passages that connect the resin receiving port and the resin injection port,
In addition, these two resin passages are formed closer to each other on the runner side of the die than on the cylinder side.

According to the above method, since it is not necessary to project the sprue on the left and right side surfaces of the mold, the width of the mold can be reduced and the mold processing can be simplified. Further, it is excellent in workability that it is not necessary to dispose the two heating cylinders obliquely toward the resin receiving port provided in the center of the runner of the mold. Further, since the nozzle portion provided at the die end of the manifold and the runner of the die are in close contact with the cylinders arranged substantially in parallel, there is no resin leakage. Further, when performing single-color molding, this two-color molding manifold member can be easily detached from the heating cylinder and replaced with a single-color manifold member. This replacement work is excellent in workability because it can be performed on the heating cylinder side without disassembling the mold.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The two-color molding method and injection molding apparatus for plastic products according to the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a perspective view of a stacking / nesting type two-color container 1. FIG. 2 is a vertical cross-sectional view of an injection molding apparatus including a two-color molding manifold used in this embodiment. 3 (a) and 3 (b) are vertical cross-sectional views of an injection molding apparatus equipped with a monochromatic molding manifold used in another aspect of the present embodiment.

First, the shape of the two-color container molded in this embodiment will be described. In FIG. 1, the two-color container 1 includes a bottom plate portion 3, a pair of side walls 2c and 2d standing upright from a peripheral portion of the bottom plate portion 3, and a pair of end side walls 2a and 2b. The two-color container 1 includes a bottom plate portion 3 and a side wall 2.
Colors are divided into two colors by the joining line L on c and 2d.

In this embodiment, two types of two-color containers 1 as described above are used by using an injection molding apparatus equipped with an injection molding die 100 having a cavity 10 corresponding to the container shape as shown in FIG. The thermoplastic resin of, for example, two-color thermoplastic resin is injected and integrally molded.

The injection mold 100 shown in FIG. 2 is similar to the mold shown in FIG.
In 0, a movable mold (male) 8 and a fixed mold (female) 9
Thus, the cavity 10 having a shape corresponding to the container 1 as described above is formed. A runner block 11 having an auxiliary block 18 is fixed to one side of the fixed mold 9.

The auxiliary block 18 is provided at the innermost portion of the central recess 70 of the mold 100 on the heating cylinder 14a, 14b side so as to project in the heating cylinders 15a, 15b direction (the resin injection nozzle direction of the manifold member). Has been.
The resin suction port side end surface 72 of the auxiliary block 18 is formed by the mold 10.
The resin passage 12a is formed so as to be orthogonal to the moving direction of 0, and the resin injected from the manifold member 60 described later can be sucked into the spherical recess provided in the end face 72 on the suction port side. , 12b are open.

The runner block 11 is arranged between the auxiliary block 18 and the fixed mold 9, and the resin passage 12 in the auxiliary block 18 is disposed in the runner block 11.
Two runners 11a and 1 that communicate with a and 12b, respectively
1b are extended in opposite directions so that they are substantially parallel to the bottom surface 3 of the cavity 10. Furthermore runner 1
1a and 11b are in communication with the cavity 10 by gates (passages) 16a, 16a, 16b and 16b provided at two branches.

In FIG. 2, the two injection devices 15a and 15b for supplying the resin to the mold 100 are shown in FIG.
Are arranged substantially parallel to the moving direction of. In addition, the heating cylinder 14 is provided in each of the two injection devices 15a and 15b.
a, 14b are provided, and the heating cylinders 14a,
A manifold member 60 as described below is removably disposed in each of the resin injection ports 50a and 50b of 14b.
It is designed to be in close contact with the auxiliary block 18 of the mold 100.

That is, the manifold member 60 includes
Resin receiving ports 80a and 80b are provided at positions corresponding to the injection ports 50a and 50b of the heating cylinders 14a and 14b, and at the time of injection molding, the resin injection port 50 of the heating cylinder is provided.
a, 50b and the resin receiving ports 80a, 8 of the manifold 60
0b is tightly fixed by a bolt or the like not shown. Further, in the manifold member 60, a nozzle portion 62 projects at a position corresponding to the resin receiving ports 73a and 73b provided in the auxiliary block 18 of the mold 100, and an opening 73a of the auxiliary block 18 is formed at the tip of the nozzle portion 62. , 73b are provided so that the resin injection ports 13a, 13b are provided in a protruding manner. Moreover, the manifold member 60 has the resin receiving ports 80a, 80b and the resin injection ports 13a, 13
Resin passages 82a and 82b that communicate with b are provided. Further, in FIG. 2, these two resin passages 82a, 8a
2b is formed closer to the mold runner side than to the cylinder side. In other words, the cylinder side resin suction port 80
The mutual distance between the auxiliary block 18 side resin injection ports 13a-13b is smaller than the mutual distance between a-80b.

Therefore, such a manifold member 60
Is used, the resin suction port (supply port) 73 is provided at the center of the mold.
Even if a and 73b are formed close to each other, the two-color molding of the molded body can be performed with the two heating cylinders 14a and 14b being arranged in parallel to the moving direction of the mold. That is, it is not necessary to direct the two heating cylinders 14a and 14b to the direction of the auxiliary block 18 provided at the center of the mold, and the workability is excellent. Further, by using the mold 100 in which the resin suction ports (supply ports) 73a and 73b are provided in the central portion of such a mold, the mold width can be reduced even in the case of two-color molding, It is easy to make a mold.

In the above description, an example in which the injection mold shown in FIG. 2 is used when integrally molding the two-color container 1 has been given, but the injection mold used in the present invention is not limited to this example. Not something.

For example, the number of gates communicating with the cavity 10 may be such that at least one gate communicates with each injection device, and the number is not limited even when a plurality of gates are provided. The position of such a gate is appropriately set depending on the shape of the obtained container. For example, when a substantially symmetrical container is to be obtained, the resin gates of the respective colors are connected to the joining line of the two colors. On the other hand, it is preferable that they are provided substantially symmetrically to the left and right.

The injection device may be a screw type or a plunger type as described above. In the above-mentioned manifold member 60, two resin inlets 80a and 80b and two resin supply ports 13a and 13b are shown. However, in the case of single-color molding, the manifold member 6 is used.
As shown in FIG. 3A, one resin suction port 80c into which a kind of resin injected from one heating cylinder 14a (or 14b) flows in 0a, and one resin suction port 80c It is possible to use the one in which the branch passage 82c is formed so as to divide the sucked (flowed) resin into the two resin supply ports 13a and 13b. Such a manifold member 60 and a manifold member 60a can be easily replaced by removing a fixing member (not shown) for joining and fixing the heating cylinders 14a and 14b and the manifold 60 (60a).

If the auxiliary block has a single resin inlet (supply port) (not shown), a manifold member 60b as shown in FIG. 3B can be used. , Two resin suction ports 80a, 80b into which the resin injected from the two heating cylinders 14a, 14b for injecting the same type of resin flows, and one resin suctioned (flowed in) from the resin suction ports 80a, 80b A resin passage is formed so that the resin passage can be joined to the resin supply port 13c.

In order to integrally mold the two-color container 1 using the above-mentioned injection molding apparatus, first, the two-color containers 1 are melted separately,
The heating cylinders 14a and 14b are operated by operating the screws (not shown) in the injection devices 15a and 15b, respectively, which are used to resin different from each other and colored in different colors.
The respective nozzles 13a and 13b provided at substantially the center of the manifold member 60 disposed at the resin injection port of the above injections into the in-mold passages 12a and 12b. The resin injected into the mold flows into the runners 11a and 11b from the passages 12a and 12b provided in the substantially central portion of the auxiliary block 18, and is press-fitted into the cavity 10 through the gates 16a, 16a, 16b and 16b. To be done. In this way, the two-color resin press-fitted into the cavity 10 joins together at the center of the bottom plate portion 3 in the left-right direction inside the cavity 10 to form a joining line L, and the resin supply (filling) is completed. The desired two-color container 1 is molded.

The merging line L may be formed on the left side or the right side of the container 1 which is color-coded to the left and right when the container 1 is viewed from the rear surface direction of the bottom plate. The two-color container 1 obtained by completing such injection molding is taken out by moving the movable mold 8 after an appropriate cooling time.

The two-color thermoplastic resins colored in mutually different colors, which are used when integrally molding such a two-color container 1, usually include a thermoplastic resin and a pigment (dye). There is.

As the thermoplastic resin, a resin that is widely used when injection-molding plastic is generally used without particular limitation. Examples thereof include polypropylene (PP), polyethylene (PE), ABS resin, polystyrene (PS), polycarbonate (PC), polyvinyl acetate (EVA resin), polyamide (PA), polyacetal (POM) and the like.

The thermoplastic resins charged in the injection devices 15a and 15b are different in color, that is, only different in pigment (dye) or composition ratio thereof, and it is preferable to use the same resin.

As the pigment to be blended with the resin, pigments or dyes generally used for coloring plastics are used without particular limitation. Furthermore, in the thermoplastic resin, depending on the intended use of the resulting container,
Additives such as heat resistance stabilizers and weather resistance stabilizers, glass fibers, fillers such as fillers, etc. are appropriately mixed.

Such a thermoplastic resin is generally injection-molded under the conditions such as the melting temperature and the pressure when the plastic is injection-molded, but in the present invention, as described above, they are injected from different directions. It is carried out while adjusting the injection pressure and the like so that the melted resin thus obtained merges at a desired position, usually in the approximate center of the cavity 10.

According to this embodiment, since the injection molding apparatus having the manifold 60 as described above is used, the mold 100 is larger than the heating cylinders 14a and 14b.
In the case of a small size, it is possible to integrally form the two-color container by arranging the two cylinders substantially in parallel without arranging the two cylinders so as to intersect each other on their extension lines as shown in FIG.

Further, in the case where after performing the two-color molding of the container in this manner and performing the single-color molding using the same mold, the manifold member 60 is connected to the heating cylinder 14a,
Loosen the bolts (not shown) attached to 14b and remove the manifold member 60.
Instead of 0, the monochrome manifold member 60a shown in FIG.
Can be attached. Further, by removing the manifold 60, the two heating cylinders 14a and 14b are obliquely arranged and ejected using the mold shown in FIG. 2 or 3 with respect to the movable direction of the mold as in the conventional case. It can also be molded.

Since it is not necessary to disassemble the mold during such work, the manifold replacement work is extremely easy. Although one embodiment of the present invention has been described above, 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, although the two-color container has been described as an example in the above embodiments, the present invention can be applied to various two-color molded products. Further, in the above two-color container, for example, the bottom plate portion may be provided with a plurality of holes for draining water or the like.

[0040]

As described above, according to the method for integrally molding a two-color container according to the present invention, the manifold is provided at the injection ports of the cylinders arranged substantially in parallel,
Moreover, since the end surface of the runner block is arranged so as to face the nozzle at the tip of the manifold, the nozzle can be fitted well. Therefore, the flow of resin is improved. Also,
When performing single-color molding, the manifold provided with this nozzle can be detached from the cylinder and easily replaced with a single-color one. Since this replacement work can be performed on the injection machine side without disassembling the mold, the workability is extremely good.

[Brief description of drawings]

FIG. 1 is a perspective view of a two-color container obtained by the present invention.

FIG. 2 is a vertical sectional view of an injection molding apparatus provided with a manifold member used in the present invention.

FIG. 3 is a vertical cross-sectional view of a monochromatic manifold member used in another embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of an injection molding device used in a conventional example.

[Explanation of symbols]

1 ... Two-color container, 3 ... Bottom plate part, 8 ... Movable mold, 9 ... Fixed mold, 10 ... Cavity, 11 ... Runner block, 11a, 11b, 12a, 12b, 82a, 82b ... Resin passage, 13a, 13b ... Manifold nozzles, 14a, 14b ... Cylinders, 15a, 15b ... Injection devices, 16a, 16b ... Gates, 18 ... Runner block auxiliary blocks, 50a, 50b ... Heating cylinder resin injection ports, 60, 60a, 60b ... Manifolds Members, 62 ... Nozzle part, 80a, 80b ... Manifold resin suction port (inlet), 100 ... Mold.

Claims (4)

[Claims] 1. A heating cylinder equipped with two heating cylinders for respectively melting thermoplastic resins colored differently from each other, and guiding the resins of different colors injected from these heating cylinders to a runner of a die, In the two-color molding method for a plastic product, in which these resins are supplied to the cavity from the above, and these resins are joined together in the cavity to integrally mold, the heating cylinders are arranged so as to be substantially parallel to each other. A manifold member is detachably mounted on the heating cylinder, and a resin receiving port is provided on the manifold member at a position corresponding to the injection port of the heating cylinder, and is provided on the runner of the mold. A resin injection port is provided at a position corresponding to the resin reception port, and a resin passage that connects the resin reception port and the resin injection port is provided. A two-color molding method for a plastic product, characterized by using an injection molding device. 2. The manifold member is provided with two resin passages that communicate the resin receiving port and the resin injection port, and these two resin passages are provided on the mold side rather than the cylinder side. 2. The two-color molding method according to claim 1, wherein an injection molding device formed close to each other on the runner side is used. 3. Equipped with two heating cylinders for melting each thermoplastic resin separately, the resins injected from these heating cylinders are guided to a mold runner, and these resins are supplied to the cavity from the runner, In a molding device for a plastic product in which these resins are joined together in the cavity for integral molding, the heating cylinders are arranged so as to be substantially parallel to each other, and the heating cylinder is detachably attached to the manifold. A member is provided, a resin receiving port is provided in the manifold member at a position corresponding to the injection port of the heating cylinder, and a resin injection port is provided at a position corresponding to the resin receiving port provided in the runner of the mold. And a resin passage that connects the resin receiving port and the resin injection port are provided. Place 4. The manifold member is provided with two resin passages that connect the resin receiving port and the resin injection port, and these two resin passages are located on the mold side rather than the cylinder side. The injection molding apparatus according to claim 3, wherein the injection molding apparatuses are formed close to each other on the runner side.