JP2561779B2 - Hollow molded article manufacturing method and hollow 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 for producing a blow molded product and a blow molding machine, and more particularly to all resins from an inlet of an adapter connected to an extruder to a die / core portion which is an outlet of a crosshead. The present invention relates to a new improvement for making a flow path resistant to high heat and wear.

[0002]

2. Description of the Related Art As a conventional method for producing a hollow molded article of this type, there can be mentioned, for example, the method for producing a blow-molded container disclosed in JP-A-61-10432. That is, the method disclosed in the above-mentioned publication is a method for manufacturing a blow-molded container for extruding and blow-molding polyolefin to manufacture a container. Then, polyolefin is extruded through the resin passage to form a parison, and the parison is blow-molded.

[0003]

Since the conventional method for producing a hollow molded article is configured as described above, the following problems have been encountered. That is, the fluororesin (trade name: Teflon) coated on the resin flow path has low heat resistance, and the engineering resin having a resin temperature of 270 ° C. or higher cannot be used because the fluororesin coating is also dissolved. In addition, the coating material (coding portion) of the fluororesin is often damaged by the additive material and foreign matter (dust) added to the resin, which makes it unusable. Further, since the coating film of this fluororesin is relatively soft, it may be accidentally damaged when cleaning the adapter or the crosshead, and it may become unusable. In addition, the smoothness with the resin in the flow path due to thermal spraying of metal plating ceramics such as Cr plating and titanium carbide and the outer surface condition of the parison ejected from the crosshead are the same as those of fluorine resin. The dryness was bad and a high quality hollow molded product could not be molded.

The present invention has been made to solve the above problems, and particularly, all resin flow from the inlet of the adapter connected to the extruder to the die / core portion which is the outlet of the crosshead. It is an object of the present invention to provide a method for producing a hollow molded article having a high heat resistance and wear resistance in a passage and a hollow molding machine.

[0005]

According to the method for producing a hollow molded article according to the present invention, a resin extruded from an extruder is supplied to a mold as a parison through an adapter and a crosshead to mold the hollow molded article. In the method for manufacturing a hollow molded article, the parison is formed through the tungsten carbide coating film formed on the resin flow paths of the adapter and the crosshead.

More specifically, the tungsten carbide coating film is formed by thermal spraying and then the surface thereof is polished.

The blow molding machine according to the present invention is a blow molding machine in which resin extruded from an extruder is supplied as a parison to a mold through an adapter and a crosshead to form a blow molded product. A first tungsten carbide coating formed on the first resin flow path of the adapter;
And a second tungsten carbide coating film formed on the second resin flow path of the crosshead.

[0008]

In the method for producing a hollow molded article and the hollow molding machine according to the present invention, since the tungsten carbide coating film is formed on all the resin flow paths of the adapter and the crosshead, the resin extruded from the extruder is It is supplied to the die / core portion of the crosshead through the tungsten carbide coating, and is supplied from the die / core portion to the die as a cylindrical parison for hollow molding. In addition, when the tungsten carbide coating is coated between the adapter and the die / core portion, less stagnant resin is generated due to changes in the direction and area of the resin flow path. In addition, even if only the die / core part is coated with a tungsten carbide coating,
The parison injected from the core part can obtain a product with a high surface condition. In the above case, since this tungsten carbide coating is formed by thermal spraying,
It is possible to use all types of olefin resin (maximum operating temperature of about 240 ° C) to engineering plastics (maximum operating temperature of about 290 ° C), and it is possible to obtain high durability and high quality hollow molded products.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for producing a hollow molded article and a hollow molding machine according to the present invention will be described in detail below with reference to the drawings. 1 and 2 show a blow molding machine according to the present invention. FIG. 1 is a sectional view showing the entire structure, and FIG. 2 is an enlarged sectional view showing a main part of FIG.

In FIG. 1, reference numeral 1 denotes a cylinder in which a screw 2 is rotatably incorporated, and a plurality of heater blocks 3 for raising the temperature of the cylinder 1 itself are provided on the outer periphery of the cylinder 1. Has been.

A hopper 5 for supplying the material 4 into the cylinder 1 is connected to a supply port 1b provided at the rear end 1a of the cylinder 1, and a tip 1c of the cylinder 1 is connected to the hopper 5. A crosshead 7 is connected via an adapter 6, and the cylinder 10, the screw 2, the hopper 5, and the like described above constitute an extruder 10.

The extruder 1 is attached to the axial center of the adapter 6.
A first resin flow passage 11 for guiding the molten resin extruded from the cylinder 0 of 0 to the crosshead 7 is formed, and a tungsten carbide is provided on the inner surface of the first resin flow passage 11. A first tungsten carbide coating film 11a having a structure in which the surface is polished after being sprayed by thermal spraying is formed.

The cross head 7 connected to the adapter 6 is formed with a second resin flow channel 12 which is orthogonal to the first resin flow channel 11 and is connected in a cross shape. A second tungsten carbide coating film 12a formed by thermal spraying of tungsten carbide similar to that described above is formed on all of the inner wall portions.

A die 7a is provided below the crosshead 7.
And a core 7b, and a die / core portion 7c is provided, and a ring-shaped ejection port 7 formed in the die / core portion 7c.
d communicates with the second resin flow channel 12.

At a position below the crosshead 7, a cylindrical parison 13 that is discharged from the discharge port 7d and hangs down.
A mold 14 for hollow molding is provided, and the mold 14 is a first mold part 14 that is provided so as to be openable and closable with respect to each other.
a and the second mold part 14b.

The blow molding machine according to the present invention is constructed as described above, and a method for producing a blow molded product will be described below. First, the molten resin extruded from the cylinder 1 of the extruder 10 is the first resin in the first resin flow path 11 of the adapter 6.
The tungsten carbide coating 11a passes through the second tungsten carbide coating 12a of the second resin flow path 12 of the crosshead 7 and the discharge port 7d of the die / core portion 7c.
Is inserted into the mold 14 as the parison 13.

The parison 13 inserted in the mold 14.
After the mold parts 14a and 14b in the mold open state are closed,
By supplying air into the parison 13 with an air blowing nozzle (not shown), a hollow molded product is molded in the mold 14. As a result of the experiment, the tungsten carbide coatings 11a and 12a are not peeled off or damaged even if all of them are used from the olefin resin type (maximum operating temperature of about 240 ° C) to the engineer plastic type (maximum operating temperature of about 290 ° C). It was confirmed that a good quality parison 13 and a hollow molded product were obtained.

[0018]

EFFECTS OF THE INVENTION Since the method for producing a hollow molded article and the hollow molding machine according to the present invention are configured as described above, the following effects can be obtained. That is, since the tungsten carbide coating film is formed on all the resin flow paths from the adapter on the outlet side of the extruder to the die / core portion which is the outlet of the crosshead, 240 ° C. of olifin resin type and engineer plastic type etc. Even when a high-temperature resin of from 290 to 290 ° C. is supplied, a good quality parison can be obtained without contamination of dust or the like due to damage of the flow path as in the conventional case. Also, compared to conventional fluororesin coating,
Its hardness is high, and it is not damaged even during cleaning after the molding work, and high reliability can be obtained for a long time.
Further, even if damage occurs, since the thickness of the coating is large, it can be easily repaired again by polishing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a blow molding machine according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of FIG.

[Explanation of symbols]

 6 Adapter 7 Crosshead 10 Extruder 11,12 Resin Flow Path 11a, 12a Tungsten Carbide Coating 13 Parison

Claims (3)

(57) [Claims] 1. An adapter for resin extruded from an extruder (10)
(6) and a crosshead (7) through a parison (13) as a parison (13) into the mold (14), in the method for producing a hollow molded article, the method for producing a hollow molded article, the adapter (6) and the cross A method for producing a hollow molded article, characterized in that the parison (13) is formed through the tungsten carbide coating films (11a, 12a) formed in the resin flow paths (11, 12) of the head (7). 2. The tungsten carbide coating (11a, 1a)
2. The method for producing a hollow molded article according to claim 1, wherein 2a) is formed by thermal spraying and then has its surface polished. 3. An adapter for resin extruded from the extruder (10)
In the blow molding machine, which supplies the parison (13) to the mold (14) through the cross head (6) and the cross head (7) to mold the blow molded product, the first resin flow of the adapter (6) Road (11)
First tungsten carbide film (11a) formed on
And a second tungsten carbide coating (12a) formed on the second resin flow path (12) of the crosshead (7).