JP2000052403A - Strand dies for extruder and method for preventing gum of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide strand dies for an extruder in which restoration is enabled at a low cost without replacing the whole die plate when the inner face of a nozzle hole of a die plate has been damaged and to provide a method for preventing gums of the dies. SOLUTION: A plurality of nozzle pieces 6 in which nozzle holes 9 are opened, are screwed in a die plate 5 of strand dies for an extruder. Gum like resin blocks generated in the outer peripheral parts of the outlets of the nozzle holes 9 are prevented by replacement of the nozzle pieces 6. The number of a nozzle can be changed by substituting a nozzle plug 10 for a part of the nozzle pieces 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a strand die for an extruder.

[0002]

2. Description of the Related Art FIG. 3 shows the overall configuration of a conventionally used strand extruder. In FIG. 1, an extruder is denoted by reference numeral 11, and a strand die 12 is attached to a tip of the extruder 11. In front of the strand die 12, a cooling water tank 13 to which a drainer 14 is attached on the downstream side is disposed. A land cutter 15 is disposed in front of the drainer 14, and a vibrating screen 16 is connected to the discharge side.

In the above-mentioned strand extruder, the resin plasticized by the extruder 11 is discharged into the cooling water tank 13 as a plurality of strands (strings) 17 through a plurality of nozzle holes of a die plate 18 of a strand die 12. Is done. The strand 17 cooled in the cooling water tank 13 passes through the drainer 14 and is conveyed to the land cutter 15 to be cut. The pellets obtained by cutting were mixed with a vibrating sieve 16
At the outlet 16a.

[0004]

The conventional strand dies have the following problems. That is,
In the case where the resin raw material contains a component having a corrosive property to metals or a component having abrasion properties, for example, a halogen-based flame retardant or glass fiber, the strand is subjected to a normal extrusion operation or cleaning (incineration) operation. The inner surface of the nozzle hole of the die plate of the die and the edge of the outlet portion are damaged by corrosion and abrasion. As a result, as shown in FIG.
A resin mass 20 having a fuzzy shape is generated around the outlet portion of the above.

[0005] The eye-like resin mass 20 is formed with time.
It is deteriorated by oxygen in the air or heat from the die plate 18, and in some cases, carbonizes black. Since the deteriorated resin sometimes adheres to the strand 17 during extrusion and mixes with the product, a sorting operation is required in a later step.

[0008] The cause of the formation of the resin block 20 having a fuzzy shape largely depends on the smoothness of the inner surface of the nozzle hole 19 and the sharpness of the edge at the outlet. As a preventive measure for the eye-like resin block 20, conventionally, a hard wear-resistant and corrosion-resistant coating (TiN, TiCN, TiC, VC) is formed on the inner surface of the nozzle hole 19.
Etc.), but it is not one that can withstand long-time operation, and ultimately requires the work of newly manufacturing and replacing the die plate 18, and the cost is equivalent to the complete die plate. Would.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and when an inner surface of a nozzle hole of a die plate is damaged, it can be restored at a low cost without replacing the entire die plate. It is an object of the present invention to provide a strand die for an extruder and a method for preventing the dice from forming the die.

[0008]

The present invention has solved the above-mentioned problems as follows. That is, a plurality of nozzle pieces with a nozzle hole are screwed into a die plate of a strand die for an extruder, and an eye-like resin mass generated on an outer periphery of an outlet portion of the nozzle hole due to damage to an inner surface of the nozzle hole,
Prevent by replacing the nozzle piece.

By replacing a part of the nozzle piece with a nozzle plug, the number of nozzles can be changed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings.

FIG. 1 is a sectional view of a main part of a strand die according to one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an upstream die block, and a downstream die block 3 is fastened to the die block 1 via a breaker plate 2. A die plate 5 is attached to the downstream die block 3 via a throttle member 4. The nozzle plate 6 is screwed to the die plate 5.

The above-mentioned strand die 12 is attached to the tip of a cylinder 11a of an extruder or an adapter connected to the cylinder 11a.

FIG. 2 is an explanatory view of a die plate of a strand die. As shown in FIG. 2A, a wide resin flow path 7 is formed on the upstream side of the die plate 5.
On the downstream side of the die plate 5, a plurality of screw holes 8 communicating with the resin flow path 7 are provided so as to penetrate therethrough. As shown in FIG. 2B, nozzle pieces 6 each having a nozzle hole 9 are screwed into each screw hole 8. As shown in FIG. 2C, a part of the plurality of nozzle pieces 6 is replaced with a nozzle plug 10 so that the number of nozzles can be easily changed.

During the extrusion operation, if the inner surface of the nozzle hole 9 of the nozzle piece 6 is worn or corroded and the outer periphery of the outlet portion of the nozzle hole 9 becomes fuzzy, only the nozzle piece 6 is replaced.

[0015]

Since the present invention is configured as described above, the cost of parts and replacement can be reduced as compared with the case where the entire die plate is replaced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a strand die according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a die plate of a strand die.

FIG. 3 is an overall configuration diagram of a strand extrusion device.

FIG. 4 is a diagram showing eye-like resin blocks generated around an outlet of a nozzle.

[Explanation of symbols]

 Reference Signs List 1 die block (upstream side) 2 breaker plate 3 die block (downstream side) 4 throttle member 5 die plate 6 nozzle piece 7 resin passage 8 screw hole 9 nozzle hole 10 nozzle plug 11 extruder 11a cylinder 12 strand die 17 strand 20 resin mass

Claims (3)

[Claims] A plurality of screw holes (8) are formed downstream of a wide resin flow path (7) formed in a die plate (5), and a nozzle is formed in the screw hole (8). A strand die for an extruder, characterized in that a nozzle piece (6) having a hole (9) is screwed exchangeably. 2. A strand die for an extruder according to claim 1, wherein a part of said nozzle piece (6) is replaced with a nozzle plug (10) and the number of nozzles is changed. 3. A nozzle hole (9) in a die plate (5).
A plurality of nozzle pieces (6) with holes are screwed into the nozzle holes (9), and the eye-like resin mass (20) generated around the outlet of the nozzle hole (9) due to damage to the inner surface of the nozzle hole (9) is removed. (6) A method for preventing a strand die of an extruder, which is prevented by replacement of (6).