JP3169843B2 - Resin material supply device of molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding a synthetic resin, in which air is mixed into a resin being plasticized by a screw-type plasticizing apparatus, and the resin is oxidized (resin burns), and discoloration or carbide is generated. The present invention relates to a resin material supply device for preventing the occurrence of a problem.

[0002]

2. Description of the Related Art Conventionally, air is mixed during plasticization of a resin such as polyethylene or polypropylene with a screw-type plasticizing apparatus to cause burning of the resin, or a defective product containing carbides called black spots appears in a molded product. It is known to inject nitrogen gas into the plasticizer when supplying the granular resin material to the plasticizer in order to prevent this. 9 to 12 show a known type in which nitrogen gas is injected into a plasticizer.

FIG. 9 shows a type in which a gas injection pipe 7 is inserted from below a hopper 12 and its tip is placed near a resin material inlet 6 of a heating cylinder 2 to inject nitrogen gas. Reference numeral 10 denotes a type in which the tip of the gas injection pipe 7 is installed near the base of the heating cylinder 2 and nitrogen gas is injected. However, since both types have the hopper 12 open, the nitrogen gas flows out to the hopper side, the efficiency of replacement with air is low, and a large amount of nitrogen gas is required.

Therefore, as shown in FIG. 11, there is a device in which a lid 12 'is put on the hopper 12, but this makes it difficult to continuously supply the resin material. Therefore, there is a device capable of continuously supplying the material and shutting off the outside air. Was desired.

In order to satisfy the above demand, a type in which a shutter 23 is provided below the hopper 12 to drop the resin material and shut off the air from the atmosphere as shown in FIG. There is a drawback that a resin material is sandwiched and malfunctions easily occur.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional apparatus and enables continuous supply of resin material.
Moreover, it is an object of the present invention to provide a device capable of reliably preventing air from entering the heating cylinder, thereby preventing the occurrence of defective molded products due to the incorporation of air into the molten resin and improving the transparency of the transparent molded products. Things.

[0007]

SUMMARY OF THE INVENTION In a molding machine for preventing air from entering a heating cylinder so that air does not enter the resin during plasticization of the resin, a resin material is supplied to a hopper 12 and a heating cylinder 2. A rotary valve-type resin material supply device 13 that can supply the resin material P from the hopper 12 to the storage cylinder 10 without connecting the hopper 12 and the storage cylinder 10 is provided between the storage cylinder 10 and the storage cylinder 10 that supplies P. Then, the inert gas injection pipe 7 is inserted into the storage cylinder 10, and the inert gas injection pipe 7 is positioned below the rotary valve type resin material supply device 13 and above the gas injection port of the inert gas injection pipe 7. An exhaust pipe 8 for discharging the inert gas from the storage tube 10 is provided, and the air that enters the storage cylinder 10 together with the resin material P is replaced with the inert gas.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of a main part of the present invention. In a plasticizing apparatus 1, a heater 3 is provided on an outer circumference of a heating cylinder 2, and a screw 4 is rotatably installed in the heating cylinder 2 by a driving device 5. It has the same structure as that of. A storage cylinder 10 of the resin material P is connected to the resin material inlet 6 of the heating cylinder 2 in an airtight manner, and a gas injection pipe 7 is inserted below the storage cylinder 10. And an inert gas such as nitrogen gas is injected from a gas cylinder (not shown) or a gas generator into the lower portion of the storage cylinder and the vicinity of the resin material inlet of the heating cylinder 2 while being controlled at a predetermined pressure.

A cylinder 9 having a gas exhaust pipe 8 is provided above the storage cylinder 10. Nitrogen gas injected below the storage cylinder 10 rises inside the storage cylinder 10 and is provided in the cylinder 9. The gas is discharged from the exhaust pipe 8 to the outside. 1
Reference numeral 1 denotes a level sensor that detects the amount of resin stored in the storage tube 10.

[0010] Between the cylindrical body 9 and the hopper 12, FIG.
As shown in FIG. 3 (reference diagram), there is provided a rotary valve type resin material supply device 13 which can supply the resin material P from the hopper 12 to the storage cylinder 10 in a sealed state without connecting the two via the cylinder 9. is set up. The rotary valve type resin material supply device 1
3 is a rotary valve element 1 in a housing 16 having an inlet 14 communicating with the hopper 12 and an outlet 15 communicating with the storage cylinder 10.
7 is rotatably provided inside by a rotation driving device 18, and the rotary valve body 17 is provided with a pocket 20 in which a predetermined amount of resin material can be stored.

When the rotary valve element 17 rotates and the opening 19 of the pocket 20 reaches the position of the inlet 14 of the housing, the resin material P in the hopper 12 flows into the pocket 20 of the rotary valve element 17 and The inside is filled with a resin material P. The valve element 17 rotates to open the opening 19 of the pocket 20.
Is located at the outlet 15 of the housing 16, the resin material P in the pocket is discharged to the storage tube 10.

FIG. 4 (reference diagram) shows that the molding operation is performed, and when the resin material in the storage cylinder 10 is reduced to a predetermined level or less, the level sensor 11 is operated by a control mechanism (not shown) to operate the rotation driving device 18. It is about to rotate the rotary valve body 17 counterclockwise. 5 (Reference figure) shows the place where the rotary valve member 17 has been rotated 90 degrees from the position of FIG. In this state, the hopper 12 and the storage cylinder 10 are kept sealed by the valve element 17.

When the valve element 17 rotates further, FIG. 6 (reference drawing)
7, the opening 19 of the pocket 20 starts to communicate with the outlet 15 of the housing 16, and the resin material in the pocket 20 starts flowing out to the storage tube 10, and when it reaches the position shown in FIG. All the resin material in the pocket is discharged into the storage cylinder 10. During this time, the rotary valve body 17 always maintains a sealed state without communication between the hopper 12 and the storage cylinder 10. When the rotation of the rotary valve body 17 causes the resin material P to reach a predetermined level of the storage cylinder 10, the rotation driving device 18
Stops and the rotation of the rotary valve element 17 stops.

When the resin material P flows from the hopper 12 into the pocket 20, a small amount of air enters between the particles of the resin material P, and the air flows into the storage cylinder 10 together with the resin material P. However, from the gas injection pipe 7 to the storage cylinder 10
Nitrogen gas injected downward is accompanied by the air and the storage cylinder 1
The inside of the storage cylinder 10 is replaced with nitrogen gas, so that air can be reliably prevented from entering the heating cylinder 2.

FIG. 8 shows another embodiment, in which the installation location of the gas injection pipe 7 in FIG. 1 is provided on the cylindrical body 9 and the tip of the gas injection pipe is installed above the storage cylinder 10. It is.

[0016]

According to the present invention, the resin material is supplied into the storage cylinder 10 without causing the hopper 12 and the storage cylinder 10 to communicate with each other by the rotary valve type resin material supply device 13, and adheres to the resin material. The small amount of air that has entered the storage cylinder 10 is replaced by an inert gas such as nitrogen gas and is reliably discharged from the exhaust pipe 8 to the outside, so that continuous molding can be performed while maintaining prevention of air from entering the heating cylinder. In addition to being able to mix air into the molten resin, the transparency of the transparent molded article can be improved.

Furthermore, resins such as polyethylene and polypropylene, which are liable to burn due to oxidation during the melt plasticization process, have extremely low oxygen concentrations around the resin exposed to high temperatures, so that burning of the resin can be eliminated and the burnt resin pieces can be eliminated. Defects in molded products due to mixing are eliminated. In addition, the work of periodically disassembling and cleaning the burnt resin adhered to the screw is reduced, and the effect of contributing to the improvement of the operation rate of the molding machine is also achieved. It goes without saying that the present invention is applicable not only to injection molding machines but also to extruders and blow molding machines.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of a main part of a device of the present invention.

FIG. 2 is a longitudinal sectional front view of an apparatus provided with a rotary valve type resin material supply device (reference drawing).

FIG. 3 is a sectional view taken along line AA in FIG. 2 (reference drawing).

FIG. 4 is an operation explanatory view (reference drawing) of the rotary valve type resin material supply device.

FIG. 5 is an operation explanatory diagram (reference diagram) of the above.

FIG. 6 is an explanatory diagram (reference diagram) of the above operation.

FIG. 7 is an operation explanatory diagram (reference diagram) of the above.

FIG. 8 is a longitudinal sectional front view of a main part of another embodiment of the apparatus of the present invention.

FIG. 9 is an explanatory diagram of a known device.

FIG. 10 is an explanatory view of another known device.

FIG. 11 is an explanatory view of another known device.

FIG. 12 is an explanatory view of another known device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 plasticizing device 2 heating cylinder 3 heater 4 screw 5 driving device 6 resin material inlet 7 gas injection pipe 8 exhaust pipe 9 cylindrical body 10 storage cylinder 11 level sensor 12 hopper 13 rotary valve type resin material supply device 14 housing inlet passage 15 housing Outlet passage 16 Housing 17 Rotary valve element 18 Rotary drive 19 Pocket opening 20 Pocket 21 Screw shaft 22 Hopper chamber 23 Partition plate P Resin material L Molten resin

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-164527 (JP, A) JP-A-8-207048 (JP, A) JP-A 63-125520 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) B29C 31/00-31/10 B29C 45/18 B29C 47/10

Claims (4)

(57) [Claims] 1. A molding machine for preventing air from entering into a heating cylinder so that air does not enter the resin during plasticization of the resin, wherein a resin material is supplied to a hopper (12) and a heating cylinder (2). (P) between the storage tank (10) and the hopper (1).
A rotary valve type resin material supply device (13) capable of supplying the resin material (P) from 2) to the storage tube (10) without connecting the hopper (12) and the storage tube (10) is installed and stored. An inert gas injection pipe (7) is inserted into the cylinder (10), and an exhaust pipe (8) for discharging the inert gas from the inert gas injection pipe (7) is provided above the storage cylinder (10). A resin material supply device for a molding machine, wherein the inert gas is substituted for air that enters the storage tube (10) together with the resin material (P). 2. A rotary valve type resin material supply device according to claim 1, further comprising a housing having an inlet communicating with the hopper and an outlet communicating with the storage tube. The rotary valve body (17) rotatably provided in the housing (16) and the pocket (20) for accommodating the resin material (P) are formed in the rotary valve body (17). The resin material supply device for a molding machine according to claim 1, wherein: 3. An apparatus according to claim 1, wherein the inert gas injection pipe is opened to the storage cylinder near the resin material inlet of the heating cylinder. Material supply equipment for molding machines. 4. The molding machine according to claim 1, wherein a level sensor (11) for detecting a storage amount of the resin material (P) is provided in the storage cylinder (10). Resin material supply equipment.