JP2012116047A - Injection molding method, and injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding method for molding a resin molding with a two-layer structure, having almost no resin mixing at the time of the next shot, by using a preplasticating injection molding machine.SOLUTION: A preplasticating injection molding machine IMD is configured to individually provide plasticizing devices 3, 4 for plasticizing and melting resin materials 30b, 40b and an injection device IU for injecting molten resins 3b, 4b into a mold 6. A first resin flow path 3a of the first plasticizing device 3 is connected to a confluent resin flow path 1a of an injection cylinder 1. A second resin flow path 4a of the second plasticizing device 4 is connected closer to the side of an injection nozzle 5 than the first plasticizing device 3. A specified amount of the second molten resin 4b is fed out to the confluent resin flow path 1a of the injection cylinder 1 and filled thereinto, and then, the first molten resin 3b is fed out to the confluent resin flow path 1a of the injection cylinder 1 and filled thereinto. The first molten resin 3b and the second molten resin 4b in the injection cylinder 1 are injected into the mold 6 at a time by an injection plunger 2.

Description

  The present invention is a two-layered resin molding using a pre-plastic injection molding device that plasticizes with a plasticizing device separately provided with a resin raw material, feeds it to an injection plunger, and then advances and injects the injection plunger. The present invention relates to an injection molding method and an injection molding apparatus for molding a product.

  2. Description of the Related Art Conventionally, a method of molding a resin molded product having a multilayer structure using an injection molding apparatus having an inline screw type first injection unit and a second injection unit is known (for example, Patent Document 1).

  In addition, in a pre-plastic injection molding apparatus having an injection plunger, by adding a new injection unit (plunger type or in-line screw type), a resin having a multilayer structure can be obtained in the same manner as the in-line screw type injection molding apparatus. A molded product can be formed.

  However, as in Patent Document 1, an injection molding apparatus that combines an inline screw type first injection unit and an inline screw type second injection unit, or an inline screw type injection unit and a plunger type injection plunger. However, the injection molding apparatus has a problem that the injection timing and the control of the injection pressure become complicated and the machine becomes large. Further, the in-line screw type injection molding apparatus has a problem that it is disadvantageous for precision molding due to the structural factor of the backflow prevention apparatus having a check valve function attached to the tip of the screw.

  On the other hand, there is also a method of molding a resin molded product having a multilayer structure with a pre-plastic injection molding device in which a plasticizing device without an injection device is connected to an injection device having an injection plunger (for example, Patent Document 2).

JP 2003-276051 A Japanese Patent Laid-Open No. 08-281736

  However, since the pre-plastic injection molding apparatus as in Patent Document 2 is connected to a plasticizing device that does not have an injection device on the injection plunger, nozzle cleaning cannot be performed and the plasticizer is sent out from the plasticizing device at the next shot. There is a problem that the molten resin to be mixed with the molten resin remaining in the resin flow path of the injection apparatus.

  The present invention has been made in view of the above problems, and a problem to be solved is a pre-plastic injection having a simple and compact structure in which a plasticizing device having no injection device is connected to an injection device having an injection plunger. An object of the present invention is to provide an injection molding method and an injection molding apparatus in which there is almost no resin mixing at the time of the next shot despite using the molding apparatus.

  In order to achieve the above object, an injection molding method according to the present invention comprises a plasticizing device for plasticizing and melting a resin raw material, a molten resin plasticized by the device being filled in an injection cylinder, and a mold by an injection plunger. The first plastic flow path of the first plasticizing device for plasticizing and melting the first resin raw material is the joining resin of the injection cylinder The second resin flow path of the second plasticizing device for plasticizing and melting the second resin raw material is connected to the injection nozzle side from the first plasticizing device, and connected to the flow path, After a specified amount of the second molten resin plasticized and melted by the second plasticizer is sent to the merged resin flow path of the injection cylinder, the first molten resin is sent to the merged resin flow path of the injection cylinder. Filled in the injection cylinder A first molten resin and the second molten resin, and is characterized in that injected into the mold at a time by the injection plunger.

  Next, an injection molding apparatus according to the present invention includes a plasticizing apparatus for plasticizing and melting a resin raw material, and an injection cylinder filled with a molten resin plasticized by the apparatus and injected into a mold by an injection plunger. The first plastic flow path of the first plasticizing device that plasticizes and melts the first resin raw material is the merged resin flow path of the injection cylinder. The second resin flow path of the second plasticizing device for plasticizing and melting the second resin raw material is connected to the injection nozzle side of the first plasticizing device. To do.

  In the injection molding apparatus of the present invention, it is preferable that the connection location of the second resin flow path of the second plasticizing apparatus is close to the injection nozzle.

  Since the injection molding method of the present invention uses a simple and compact pre-plastic injection molding device in which the plasticizing device and the injection device are independent, a precise two-layered resin molded product is molded regardless of the installation location of the device. can do. The pre-plastic injection molding device used in this injection molding method is such that the second resin flow path of the second plasticizing device for plasticizing and melting the second resin raw material is connected to the injection nozzle side than the first plasticizing device. Therefore, when the second molten resin plasticized and melted by the second plasticizer is sent to the merged resin flow path of the injection cylinder, the first molten resin remaining in the merged resin flow path is The second molten resin is pushed back to the injection plunger side by the fed second molten resin, and the second molten resin is filled in the tip portion (injection nozzle side) in the injection cylinder, and the first The molten resin is filled on the injection plunger side in the injection cylinder. Therefore, the boundary between the second molten resin and the first molten resin becomes clear, and the first molten resin remaining in the merged resin flow path and the second molten resin sent out from the second plasticizing device After that, even if the first molten resin is filled in the merging resin flow path and injected into the mold, the two layers of molten resin are hardly mixed. A resin molded product can be obtained. When the resin molded product is molded in this manner, the second molten resin forms the surface layer of the resin molded product, and the first molten resin forms the core layer of the resin molded product.

  Next, the injection molding apparatus of the present invention connects the second resin flow path of the second plasticizing device to the injection nozzle side of the first plasticizing device, so that the pre-plastic injection of a simple and compact structure Regardless of the molding apparatus, it is possible to mold a resin molded product having a two-layer structure with almost no resin mixing during the next shot. Further, since the first plasticizing device and the second plasticizing device that do not have an injection device are used, injection is only required once, and complicated control such as injection timing and injection pressure becomes unnecessary. Furthermore, when there is an existing pre-plastic injection molding apparatus, the resin as described above can be simply improved by connecting the second resin flow path of the second plasticizing apparatus to the merging resin flow path of the apparatus. It is possible to obtain an injection molding apparatus that can form a resin molded product having a two-layer structure with little mixing.

  In particular, the injection molding apparatus in which the connection point of the second resin flow path of the second plasticizing apparatus is in the immediate vicinity of the injection nozzle remains in the merged resin flow path when the second molten resin is sent out. Since almost all of the first molten resin is pushed back to the injection plunger side by the second molten resin, the two types of molten resin are hardly mixed. Thereby, the first molten resin is hardly mixed with the surface layer of the two-layered resin molded product formed of the second molten resin, and a high-quality two-layered resin molded product can be obtained. .

It is sectional drawing which shows the injection molding apparatus used for the injection molding method which concerns on one Embodiment of this invention. It is explanatory drawing which shows the injection molding method which concerns on one Embodiment of this invention. It is explanatory drawing which shows the injection molding method. It is explanatory drawing which shows the injection molding method. It is explanatory drawing which shows the injection molding method. It is explanatory drawing which shows the injection molding method. It is explanatory drawing which shows the injection molding method. It is explanatory drawing which shows the process in which the resin molded product of a two-layer structure is shape | molded by the same injection molding method.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

The injection molding method of the present invention is to mold a two-layered resin molded article using an injection molding apparatus IMD (Injection Molding Device) shown in FIG. This injection molding apparatus IMD includes a plasticizing device 3 that plasticizes and melts the first resin raw material 30b into the first molten resin 3b, and a second molten resin that plasticizes and melts the second resin raw material 40b. 4b, and an injection unit IU (Injection Unit) for filling the injection cylinder 1 with the molten resin 3b, 4b plasticized by the devices 3 and 4 and injecting it into the mold 6 by the injection plunger 2 And the first plastic flow path 3a of the first plasticizing apparatus 3 is connected to the merged resin flow path 1a of the injection cylinder 1. At the same time, the second resin flow path 4 a of the second plasticizing device 4 is connected to the merged resin flow path 1 a closer to the injection nozzle 5 than the first plasticizing device 3.
The “first resin raw material 30b” and the “second resin raw material 40b” referred to herein are powdery or granular solids having a diameter of about several millimeters to several centimeters. In the embodiment, polypropylene) is used.
In addition, the “first molten resin 3b” and the “second molten resin 4b” mean that the “first resin raw material 30b” and the “second resin raw material 40b” have a glass transition temperature or higher or a melting point or higher. It refers to a fluidized state by holding.
Further, the “resin molded product” refers to an article molded into a predetermined shape by cooling and solidifying the “first molten resin 3b” and “second molten resin 4b” in the mold 6. Say.

  The injection device IU is a device for injecting plasticized molten resins 3b and 4b, and includes an injection cylinder 1, an injection plunger 2, and a cylinder piston 7, as shown in FIG.

  The injection cylinder 1 is a substantially cylindrical member, and as shown in FIG. 1, a merged resin flow path 1a into which the molten resins 3b and 4b plasticized by the plasticizing devices 3 and 4 are fed is formed. Has been. Further, an injection nozzle 5 that is an injection port for injecting the molten resins 3b and 4b fed into the injection cylinder 1 is formed at the tip thereof.

  As shown in FIG. 1, the injection plunger 2 is a substantially columnar member that is inserted into the internal space 1 b of the injection cylinder 1 from the base end portion of the injection cylinder 1. This is for extruding the plasticized molten resins 3b, 4b fed into the internal space 1b and injecting them from the injection nozzle 5.

  The cylinder piston 7 is a power source of the injection device IU, and when the cylinder piston 7 moves in the front-rear direction, the injection plunger 2 is slid in the front-rear direction along the injection cylinder 1 so that the molten resins 3b, 4b are discharged. It is injected into the mold 6.

  As shown in FIG. 1, the first plasticizing device 3 connected to the merged resin flow path 1a of the injection cylinder 1 plasticizes the powdery or granular first resin raw material 30b into a molten resin 3b. This is a device for sending out to the merging resin flow path 1a of the injection cylinder 1, and comprises a screw 3c and a hopper 3d. A first resin flow path 3a for supplying the first molten resin 3b plasticized by the first plasticizing device 3 to the merged resin flow path 1a is formed inside the first resin resin. The flow path 3 a is connected to the proximal end portion (near the injection plunger 2) of the merged resin flow path 1 a of the injection cylinder 1.

  As shown in FIG. 1, the screw 3 c is a member that is inserted into the inner space from the base end portion of the first plasticizing device 3, and the outer peripheral surface has an inner portion of the first plasticizing device 3. Spiral blades that are substantially in contact with the inner peripheral surface of the space are formed.

  Moreover, as shown in FIG. 1, the hopper 3d is a funnel-shaped member for supplying the powdery or granular first resin raw material 30b to the internal space of the first plasticizing device 3, and its upper surface. Is formed with an opening, and the lower end of the hopper 3 d is connected to the internal space of the first plasticizing device 3. When the powdery or granular first resin raw material 30b is introduced from the opening on the upper surface of the hopper 3d, the first resin raw material 30b moves to the internal space of the first plasticizing device 3. The internal space of the first plasticizing device 3 is set to a temperature at which the first resin raw material 30b is plasticized and melted, and is further rotated into the internal space of the first plasticizing device 3 by rotating the screw 3c. Thermal energy and mechanical energy (friction force, shearing force) are applied to the moved first resin raw material 30b, and the temperature of the first resin raw material 30b is increased and melted (plasticized). The first molten resin 3b is obtained while being kneaded to become a material.

  As shown in FIG. 1, the second plasticizing device 4 is also a device for plasticizing the powdery or granular second resin raw material 40 b into a molten resin 4 b and sending it to the joining resin flow path 1 a of the injection cylinder 1. However, it has the same screw 4c and hopper 4d as the first plasticizing device 3 described above. And the 2nd resin flow path 4a for supplying the 2nd molten resin 4b plasticized with the 2nd plasticizing apparatus 4 to the confluence | merging resin flow path 1a of the injection cylinder 1 is formed in the inside. The second resin flow path 4a is connected to the front end of the merging resin flow path 1a (near the injection nozzle 5).

The injection molding method of the present invention is to mold a two-layered resin molded product using the injection molding apparatus IMD having the above-described configuration. That is, first, the second resin raw material 40b is introduced into the hopper 4d connected to the second plasticizing device 4 and the first hopper 3d connected to the first plasticizing device 3 is also connected to the first plasticizing device 3. By introducing the resin raw material 30b and rotating the screws 3c and 4c, the resin raw materials 30b and 40b are plasticized to form molten resins 3b and 4b.
Although not shown here, a mold 6 is fitted to the injection nozzle 5 formed at the tip of the injection cylinder 1.

  Next, the opening / closing valve 4e provided at the connection point between the joining resin flow path 1a of the injection cylinder 1 and the second resin flow path 4a of the second plasticizing device 4 is opened, and as shown in FIG. The second molten resin 4b is sent to the merging resin flow path 1a of the injection cylinder 1. At this time, the injection plunger 2 is fed while applying back pressure (loading a predetermined pressure toward the injection nozzle 5), so that the density of the molten resin 4b filled in the injection cylinder 1 becomes uniform. Thus, a resin molded product with stable quality can be obtained. Thus, when the filling operation of the prescribed amount of the second molten resin 4b is completed, the on-off valve 4e is closed, and the communication flow path between the second resin flow path 4a and the merged resin flow path 1a is shut off.

  As described above, when the prescribed amount of the second molten resin 4b is filled, the on-off valve provided at the connection point between the joining resin flow path 1a of the injection cylinder 1 and the first resin flow path 3a of the first plasticizing device 3 3e is opened, and the first molten resin 3b is sent out to the merging resin flow path 1a of the injection cylinder 1 as shown in FIG. At this time, similarly to the above, the molten resin 3b is sent out while applying a back pressure (loading a predetermined pressure toward the injection nozzle 5) with the injection plunger 2. Since the merged resin flow path 1a is already filled with the prescribed amount of the second molten resin 4b, the first molten resin 3b is filled closer to the injection nozzle 5 than the end of the second molten resin 4b. Instead, the flow of the first molten resin 3b changes to the base end side of the injection cylinder 1 with the end of the second molten resin 4b as a boundary, and fills the internal space 1b of the injection cylinder 1.

  As described above, when the first molten resin 3b and the second molten resin 4b are filled in the merged resin flow path 1a and the internal space 1b of the injection cylinder 1, the on-off valve 5e provided in the injection nozzle 5 is opened. At the same time, the molten resin 3b, 4b plasticized by pushing the injection plunger 2 toward the tip of the injection cylinder 1 is injected into the mold 6 and filled into the internal space of the mold 6. At this time, as shown in FIG. 8A, first, the mold 6 is filled with the second molten resin 3 b filled on the tip side of the injection cylinder 1. Next, as shown in FIG. 8 (b), the first molten resin 3b filled in the base end portion (injection plunger 2 side) of the injection cylinder 1 is injected into the mold 6, and the mold is first moved. The center of the mold 6 is filled while the second molten resin 4b filled in the mold 6 is expanded toward the inner peripheral surface of the mold 6. When injection is completed in this way, the on-off valve 5e is closed and the mold 6 is removed from the injection cylinder 1. When the molten resins 3b and 4b are solidified, the second molten resin 4b forms a surface layer and the first molten resin 3b forms a core layer. Is formed.

  As described above, when the first injection (first shot) is completed, as shown in FIG. 4, the first molten resin 3 b is formed in the merged resin flow path 1 a of the injection cylinder 1 and the internal space 1 b of the injection cylinder 1. Remains. Here, in the injection molding apparatus IMD used for the injection molding method of the present invention, the second resin flow path 4a of the second plasticizing apparatus 4 has a combined resin flow on the injection nozzle 5 side with respect to the first plasticizing apparatus 3. Since the first molten resin 3b remains in the merged resin flow path 1a and the internal space 1b of the injection cylinder 1 shown in FIG. When fed out, as shown in FIG. 5, the first molten resin 3b remaining in the merged resin flow path 1a and the internal space 1b of the injection cylinder 1 is replaced with the second molten resin 4b on the injection plunger 2 side (injection cylinder 1). (Inside the internal space 1b side), it is filled while being pushed back (the injection plunger 2 moves backward by the volume of the second molten resin 4b fed out). However, since the injection molding apparatus IMD used for the injection molding method of the present invention is a simple and compact pre-plastic injection molding apparatus, the first molten resin 3b and the second molten resin 4b are independently injected. I can't. For this reason, even if nozzle cleaning cannot be performed and the second molten resin 4b is sent out from the state in which the first molten resin 3b remains in the merged resin flow path 1a, the merged resin flow path 1a and the second resin The first molten resin 3b remains in the merged resin flow path 1a between the connection portion with the flow path 4a and the injection nozzle 5. Thus, if the 1st molten resin 3b is left in the confluence | merging resin flow path 1a, it will mix with the 2nd molten resin 4b which forms a surface layer in the metal mold 6 in the next shot. Thus, a two-layered resin molded product having a surface layer in which the first and second molten resins 3b and 4b are mixed will be obtained. In order to minimize the mixing of the two types of resins 3b and 4b, the injection molding apparatus IMD of the present invention has a connecting portion between the merged resin flow path 1a and the second resin flow path 4a as shown in FIG. In the vicinity of the injection nozzle 5.

  Then, as shown in FIG. 6, when the prescribed amount of the second molten resin 4b is sent to the merged resin flow path 1a, the injection plunger 2 is further retracted by the volume of the sent second molten resin 4b, Thereafter, the on-off valve 4e provided at the connection point between the joined resin flow path 1a of the injection cylinder 1 and the second resin flow path 4a of the second plasticizing device 4 is closed, and the joined resin flow path 1a of the injection cylinder 1 and the second The on-off valve 3e provided at the connection point of the first resin flow path 3a of one plasticizing device 3 is opened, and the first molten resin 3b is sent to the injection cylinder 1. In this way, when the first molten resin 3b is sent to the merged resin flow path 1a, the first molten resin 3b tries to push the already filled second molten resin 4b toward the injection nozzle 5 side. Although the force works, the on-off valve 4e at the connection point between the merging resin flow path 1a and the second resin flow path 4a and the on-off valve 5e on the injection nozzle 5 side are closed, so that the second molten resin 4b flows backward. Rather, the second molten resin 4b plays a role like a wall, and the first molten resin 3b is prevented from being filled before that, as shown in FIG. Is filled in the inner space 1b of the injection cylinder 1 without being filled in the front end side of the merged resin flow path 1a of the injection cylinder 1 (the injection plunger 2 is supplied with the first molten resin 3b sent out). The injection plunger 2 is further retracted by the volume ofIn this way, after the first molten resin 3b remaining in the merged resin flow path 1a is pushed back to the injection plunger 2 side by sending out the second molten resin 4b, the first molten resin 3b is filled. As a result, the boundary between the second molten resin 4b and the first molten resin 3b becomes clear, and the molten resins 3b and 4b are always filled in the merged resin flow path 1a and the internal space 1b of the injection cylinder 1. After that, even if the first molten resin 3b and the second molten resin 4b in the injection cylinder 1 are injected into the mold 6 at a time as described above, back pressure is applied by the injection plunger 2. However, since the molten resins 3b and 4b are sent out, the resin density of the molten resins 3b and 4b can be kept constant, and a two-layered resin molded product having a stable quality with almost no resin mixing can be formed.

  In the present embodiment, the first injection (first shot) is performed by filling the injection cylinder 1 first with the second molten resin 4b in a clean state in which the molten resin 3b, 4b is not filled at all. Although the aspect which performs is described in full detail, there also exists an aspect which starts, after filling the injection cylinder 1 with the 1st molten resin 3b. That is, in a state where the mold 6 is not attached to the injection nozzle 5, the first molten resin 3b is sent and filled into the merged resin flow path 1a, and in this state, the injection plunger 2 is advanced and injected (free shot). When the free shot is completed, the state shown in FIG. 4 described above, that is, the state in which the first molten resin 3b remains in the merged resin flow path 1a, and thereafter, as described above, the second molten resin is obtained. 4b is sent out to push the first molten resin 3b remaining in the merged resin flow path 1a back to the injection cylinder 1 side (FIG. 5), and then the first molten resin 3b is sent out to fill the injection cylinder 1 (FIGS. 6 and 7), and finally, the injection plunger 2 is advanced and injected, so that a resin molded product having a two-layer structure with almost no resin mixing can be formed as in the above-described embodiment. In particular, this embodiment starts after the first molten resin 3b is filled into the merged resin flow path 1a by free shot, and the molten resins 3b and 4b are always added to the merged resin flow path 1a and the injection cylinder 1. Since the molten resin 3b, 4b can be sent out while applying back pressure by the injection plunger 2 in a state in which the internal space 1b is filled, the molten resin can be used rather than starting from an empty state in the merged resin flow path 1a. It can be said that the density of 3b and 4b can be kept constant, and it can be said that it is a preferable form which can obtain a resin molded product with good quality stably from the beginning.

  As is clear from the above description, the injection molding method and injection molding apparatus IMD of the present invention uses a simple and compact pre-plastic injection molding apparatus IMD in which the plasticizing apparatuses 3 and 4 and the injection apparatus IU are independent. It is easy to secure the installation location, and it is possible to mold a resin molded product with a precise two-layer structure. Further, by using the first plasticizing device 3 and the second plasticizing device 4 that do not have the injection device IU, injection is only required once, and complicated control such as injection timing and injection pressure becomes unnecessary. . In addition, in the injection molding apparatus IMD used at this time, the second resin flow path 4a of the second plasticizing apparatus 4 is connected to the injection nozzle 5 side (closest to the injection nozzle 5) than the first plasticizing apparatus 3. Therefore, when the second molten resin 4b is sent out to the merged resin flow path 1a of the injection cylinder 1, the first molten resin 3b remaining in the merged resin flow path 1a is transferred to the second molten resin flowed out. Since the first molten resin 3b and the second molten resin 4b which are pushed back to the injection plunger 2 side by the molten resin 4b and remain in the merged resin flow path 1a are hardly mixed, two types of melting are performed. It is possible to obtain a two-layered resin molded product in which the resins 3b and 4b are hardly mixed. The injection molding apparatus IMD having such an excellent effect is connected to an existing pre-plastic injection molding apparatus having one plasticizing apparatus and another plasticizing apparatus closer to the injection nozzle than the existing plasticizing apparatus. It can be obtained with a simple improvement.

  Furthermore, in the injection molding apparatus IMD of the present invention, the second resin flow path 4a of the second plasticizing apparatus 4 is connected to the injection nozzle 5 side of the first plasticizing apparatus 3 as in the above embodiment. 1 is not limited to the shape shown in FIG. 1, for example, the second resin flow path 4a is inserted into the center of the merged resin flow path 1a, and the tip opening of the second resin flow path 4a is injected into the injection nozzle. It may be an injection molding apparatus IMD extended up to 5 (closest to the on-off valve 5e). In this case, the second molten resin 4b sent out from the front end opening of the second resin flow path 4a flows backward radially around the central axis of the second resin flow path 4a, and therefore the front end opening of the second resin flow path 4a. If the trapezoidal shape is tapered, the first molten resin 3b can be smoothly pushed back into the injection cylinder 1. Alternatively, the on-off valve 5e immediately adjacent to the injection nozzle 5 can be a needle valve. In this case, the second resin flow path 4a is formed in an annular shape around the needle valve, and the tip opening thereof extends to the vicinity of the injection nozzle 5. It can cope by extending.

IMD Injection molding apparatus IU Injection apparatus 1 Injection cylinder 1a Merged resin flow path 1b Inner space of injection cylinder 2 Injection plunger 3 First plasticizing apparatus 3a First resin flow path 3b First molten resin 30b First resin raw material 3c Screw 3d Hopper 3e Open / close valve 4 Second plasticizer 4a Second resin flow path 4b Second molten resin 40b Second resin raw material 4c Screw 4d Hopper 4e Open / close valve 5 Injection nozzle 5e Open / close valve 6 Mold 7 Cylinder piston

Claims (3)

A pre-plasticizer in which a plasticizing device for plasticizing and melting resin raw materials and an injection device for filling molten plastics plasticized in the device into an injection cylinder and injecting it into a mold by an injection plunger are provided independently. In the type injection molding device,
The first resin flow path of the first plasticizing device for plasticizing and melting the first resin raw material is connected to the merged resin flow path of the injection cylinder, and the second resin raw material is plasticized and melted The second resin flow path of the plasticizing device is connected to the injection nozzle side from the first plasticizing device,
After a specified amount of the second molten resin plasticized and melted by the second plasticizer is sent to the merged resin flow path of the injection cylinder, the first molten resin is sent to the merged resin flow path of the injection cylinder. An injection molding method characterized in that the first molten resin and the second molten resin in the injection cylinder are injected into the mold at once by an injection plunger. A pre-plasticizer in which a plasticizing device for plasticizing and melting resin raw materials and an injection device for filling molten plastics plasticized in the device into an injection cylinder and injecting it into a mold by an injection plunger are provided independently. Type injection molding device,
The first resin flow path of the first plasticizing device for plasticizing and melting the first resin raw material is connected to the merged resin flow path of the injection cylinder, and the second resin raw material is plasticized and melted An injection molding apparatus, wherein the second resin flow path of the plasticizing apparatus is connected to the injection nozzle side of the first plasticizing apparatus.   The injection molding apparatus according to claim 2, wherein a connection point of the second resin flow path of the second plasticizing apparatus is close to the injection nozzle.

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