JPH10264227A - Extrusion molding method and die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent adherence of part of material released from a molding to a die lip by injecting gas from a periphery of an extrusion port toward the lip in the case of extruding melted molding material by an extruder from an extrusion port of the die. SOLUTION: The die 1 comprises an inlet 2 for introducing molding material, guide passage 3, extrusion port 4, die lip 7 and a gas inlet 6 as well as a gas injection port 5 for injecting gas to a periphery of the port 4. And, the gas is blown to the lip 7 in the port 5, and the port 5 is inclined to the lip 7 side. And, a gap channel 8 passed through the die is provided from the port 5 to the inlet 6. And, in the case of extruding the molding material from the port 4, the gas is injected from the port 5 to remove the material tending to adhere to the lip 7 by wind pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion method and a die for molding a molding material using an extruder.

[0002]

2. Description of the Related Art In order to make a molding material such as a synthetic resin into a product using an extruder, the molding material is first melted in a heating cylinder of the extruder, and then kneaded with a screw incorporated in the extruder to a die. And extrude.

[0003] The extruder is formed into various cross-sectional shapes by a die attached to the tip of the extruder. Next, the molded product is cooled and solidified by air, water, hot water or the like, and cut by a cutter or the like as necessary to obtain a predetermined product.

Here, the die attached to the conventional extruder is
There are various types of strand dies, T dies, ring dies, dies for irregular shapes, etc., and they are used depending on the shape and use of the product.

On the other hand, when extruding a molded product from a die, the molded product has not yet been completely cooled and solidified. for that reason,
Due to the adhesiveness of the molding material and the friction between the die lip and the molded product, a part of the material separated from the surface of the molded product adheres to the die lip, grows with the passage of time, becomes sludge, burns, and deteriorates to black carbon.

Further, in order to remove these, the operation of the extruder must be stopped once, and the die surface must be removed by using a tool such as a spatula.

[0007]

However, if sludge or degraded material adheres to the die lip, it will peel off from the die lip during the process of its growth and adhere to or mix with the molded product, thereby deteriorating the appearance of the product. In some cases, a product having an expected shape cannot be obtained, which causes a complaint.

Further, once the extruder is stopped and the cleaning operation is performed, the production efficiency is reduced. The present invention has been improved in view of the above.

That is, it is a technical object of the present invention to provide an extrusion molding method and a die for preventing a part of the material peeled off from the surface of a molded article from adhering to a die lip.

[0010]

Means for Solving the Problems When a molding material melted by an extruder is extruded from an extruding port of a die mounted on a tip of the extruder, gas is die-lipped from around the extruding port of the die. The extrusion molding method is characterized by spraying the mixture toward the surface.

Thus, when the molten resin is extruded from the extrusion opening, even if a part of the material peeled off from the surface of the molded article tries to adhere to the die lip due to the stickiness of the molding material and the friction between the die lip and the molded article, the gas It can be removed as if blown off by the wind pressure.

Further, even if it adheres, the temperature is lowered by the gas, so that oxidation or black carbonization can be suppressed. In addition, the present invention, pellets, films, sheets,
It can also be used in the production of bottles, laminates and the like and in the spinning of chemical fibers.

In particular, in the case of manufacturing synthetic resin pellets, a polymer heated and melted by an extruder is extruded into a strand form from a nozzle, and gas is injected from around the extrusion port of the nozzle to adhere to the extrusion port. Deteriorated substances can be removed. Here, air, nitrogen, or the like can be used as the gas to be injected.

Next, the gas flow rate is 0.1 to 20 m / sec.
c). Therefore, the flow velocity of the gas injected from the extrusion port of the die can be adjusted as appropriate in accordance with the adhesiveness of the molding material, the type of molded product, or the molding conditions. Here, the gas flow rate is represented by a value obtained by dividing the gas flow rate by the cross-sectional area of the gas flow path provided in the die.

Next, an extrusion molding method in which the molded product is a strand or a fibrous material is used. Further, an extrusion die is characterized in that a gas injection port communicating with a gas supply source is formed around the extrusion port of the die.

The die here includes any of a strand die, a ring die, a circular die, a T die, a pipe die, a die for deforming, and the like, and these dies are formed into films, sheets, pipes, profiles (irregular shapes) depending on their shapes. Products, strands, fibers, etc.

Next, an extrusion die is characterized in that at least one gas injection port is provided continuously or intermittently around the extrusion port. The gas injection port can also adjust the gas injection angle by making the gas injection port movable, and can adjust the gas injection amount by opening and closing the gas injection port.

According to the configuration of the product, it is also possible to make adjustments such as injecting gas in a concentrated manner at a portion where a part of the material is likely to adhere, in particular. Further, the die is detachable from the extruder, and an inflow port formed on the die attachment side and into which a molding material extruded from the extruder flows, and is communicated from the inflow side to the extrusion port side. A guide path for guiding the molding material, at least one extrusion port for extruding the molding material guided through the guide path, a die lip formed in the cross section on the extrusion side to define the shape of the extrusion port, and a gas toward the die lip portion Is provided.

An extrusion die is characterized by molding or laminating a molding material into a desired shape in the guide path.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) First, an outline of an extrusion molding method and a die according to the present embodiment will be described. The principle of the extrusion molding method according to the present embodiment is as follows. As shown in FIG. 7, a molding material 31 is inserted from a hopper 32, the inserted molding material 31 is melted in a heating cylinder 33 and extruded while kneading with a screw 34. In this method, the shape is adjusted with a die 35 at the tip, and the molded product is cooled and solidified with water or air.

The die 35 used in this extrusion method is mounted on the tip of the heating cylinder 33, and a gas injection port is provided continuously or intermittently around the extrusion port of the die 35. When the extruder 30 is operated, the gas is injected continuously or intermittently at predetermined time intervals from the gas injection port. (2) Next, the extrusion molding method and the die according to the present embodiment will be specifically described with reference to FIGS. Here, the extrusion molding equipment includes an extruder, a die, and a take-off device.
This is a device that is mainly required by the person. "Extruder" A commonly used extruder 30 is shown in FIG.
And a hopper 32 for supplying a powdery or granular molding material 31 made of a synthetic resin or the like as shown in FIG.
A heating cylinder 33 for heating and melting the screw, a screw 34 incorporated in the heating cylinder 33, and a heating cylinder 3
3 and a die 35 attached to the tip.

Many of the heating cylinders 33 use an electric heater 39 to heat the inside of the cylinder 33, and the entire length of the heating cylinder 33 is divided so that the temperature can be independently controlled.

Further, a cooling fan 36 may be provided so that the temperature rise due to the internal friction of the molding material can be forcibly cooled. The inner surface of the heating cylinder 33 is often made of copper nitride for the purpose of preventing abrasion and corrosion, but there are also those in which a special steel liner such as X-alloy is fitted, or those in which hard chrome plating is applied. .

The extruder 3 depends on the number of screws 34.
0 has a single-axis type and a multi-axis type. As the extruder according to the present embodiment, any of a single-screw extruder, a twin-screw extruder, and a special extruder can be used.

Next, a breaker plate 37 having a large number of holes is provided in front of the screw 34, and supports a screen 38 made of a mesh. As the extruder according to the present embodiment, a vent type extruder provided with a vent port in the middle of a cylinder can also be used. The die 35 attached to the tip of the “die” heating cylinder 33 has an inlet through which a molding material such as a molten resin flows, a guide path for providing a mold to the molding material, and the above-described guide depending on the type of molded product. A mandrel and a spider for holding the mandrel and the die body are provided in the road.

An extrusion port for extruding the molten resin, a die lip forming the shape of the extrusion port, a gas injection port for taking in gas from the outside, and a gas injection port for injecting gas around the extrusion port are provided. ing.

As the die 35, a strand die, a ring die, a T die, a pipe die, a profile die, or the like is used. Depending on the shape of the die, strands, fibers, films, sheets, pipes, profiles (profiles) and the like are used. Products with various cross-sectional shapes can be made. These extrusion dies are manufactured from materials such as tool steel, cemented carbide, and ceramics.

Next, these dies 35 are used for the molding material 31.
When the molding material is extruded from the die 35, a gas is injected from a gas injection port provided around the extrusion port of the die 35 toward the die lip, and a part of the material to be attached to the die lip is removed. Removed by wind pressure.

There are several types of dies as described below, which are obtained by further subdividing the above-mentioned dies according to the molded products manufactured by extrusion molding. First, as a die 35 used for extrusion of a pipe or tube, a ring die for pipe or tube extrusion is used, and there are a straight die, a crosshead die, and an offset die. Here, the straight die is a die for extruding molten resin on the same axis as the extruder cylinder.

Next, the crosshead die, which changes the extrusion direction, is usually used for coating wires and cables, but is also used for extrusion of tubes and hoses. The offset die is in the same axial direction as the extruder cylinder, but its position is above or below the cylinder axis.

Next, the die 35 used for forming the profile (profile) is a die for extruding the profile (profile). Here, the melt sent from the extruder is moved from the circular cross section at the entrance of the die 35 to a cross section close to the shape of the product cross section.
Can be changed within.

The cross-sectional shape of the flow path in the die 35 can be changed by changing the cross-section gradually from a circle to make the flow path a streamlined type suitable for flow (streamlined die). Simple, but can change the flow path drastically (plate die).

The die 35 used for forming a film or a sheet is a flat die or a multi-manifold die. The die 35 used for forming a film by an inflation method is a two-layer inflation die or a three-layer inflation die. It is a side supply inflation die or the like. Furthermore, the die 35 used for blow molding is a die for blow molding.

As a die used for lamination by extrusion molding, a T die is used. A molten film extruded from the T die is placed on a base material such as paper, cellophane, or aluminum foil. This is to continuously produce a composite laminate in a form in which a film and a substrate are bonded by pressure bonding between them.

Here, when a molded article is manufactured using these dies, pipes, tubes, profiles (profiled materials)
It is preferable to inject a gas such as air at a flow rate capable of preventing deformation or breakage of a film or sheet, such as waving, and effectively removing a resin or the like that is to adhere to the die lip. . The gas may be intermittently injected at regular time intervals.

The extrusion method and die according to the present embodiment include a pipe, a tube extrusion ring die, a profile (profile) extrusion die, a flat die,
Many manifold dies, inflation dies, lamination T dies, and blow molding dies can also be used. Next, the take-off machines for taking out the molded product formed by the die 35 are classified according to the form of the molded product. Machines, caterpillar type take-off machines and the like.

In the case of pellet production, a strand cutter in which a pair of take-up rolls and a cutter are combined is used. (3) Next, Embodiments 1 and 2 will be described with reference to FIGS. Example 1 A die 1 according to Example 1 has an inlet 2 into which a molding material 31 such as a molten resin flows as shown in FIG.
A guide path 3 for giving a mold to the molding material 31, an extrusion port 4 for extruding the molding material 31, a die lip 7 for forming the shape of the extrusion port 4, and a gas injection port 6 for taking in gas from the outside. And a gas injection port 5 for injecting gas around the extrusion port 4. And this gas injection port 5
The gas injection port 5 is inclined toward the die lip 7 so that gas blows on the die lip 7.

Next, from the gas injection port 5 to the gas injection port 6, a gas flow path 8 penetrating the inside of the die is provided. As shown in FIG. 2, the die 1 has annular extrusion ports 4 arranged in a line, and each of the extrusion ports 4 has an annular gas ejection port 5 for ejecting gas.

The gas inlets 6 provided at the upper and lower portions of the die 1 are connected to a gas supply source such as a cylinder or a pump via a hose 9 or the like. Next, as shown in FIG. 3, the extrusion portion of the die 1 has an extrusion port 4 for extruding a molding material.
And a die lip 7 separating the extrusion port 4 and the gas injection port 5, and a gas injection port 5 provided on the outer periphery of the die lip 7.

The molding material 31 extruded by the screw 34 of the extruder 30 flows into the die 1 from the inlet 2 of the die mounted on the tip of the extruder 30, and passes through the guide path 3 of the die 1.
And is extruded from the extrusion port 4.

At this time, the gas injection port 5 provided in the die
A gas such as air is ejected from the nip 7 to remove a material to be attached to the die lip 7 by wind pressure. Where the gas is
Spraying continuously or intermittently during the operation of the extrusion,
Alternatively, it may be intermittently sprayed every time the extrusion is stopped at regular intervals.

The gas flow rate is represented by a value obtained by dividing the gas flow rate by the cross-sectional area of the gas flow path provided in the die.
Adjustment is possible in the range of 0 m / sec. Here, the flow rate of the gas may be adjusted by restricting the valve of the gas supply source, or by providing a valve in the middle of the hose 11 or the like, and by opening and closing this valve.

Then, the molding material 31 is extruded in a strand shape (thin wire rod shape) from the die 35, cooled with water or hot water, taken up by a take-up machine, cut by a cutter or the like, and then granulated. To obtain pellets. [Embodiment 2] A die 10 according to Embodiment 2 has an inlet 1 into which a molding material 31 such as a molten resin flows as shown in FIG.
1, a guide path 12 for providing a mold to the molding material 31, an extrusion port 15 for extruding a molten resin, a die lip 16 for forming the shape of the extrusion port 15, and upper and lower 2 of the extrusion port 15.
Gas injection ports 17A and 17B for injecting gas from directions,
A gas passage 18 is provided for sending gas to the gas injection ports 17A and 17B.

The gas injection ports 17A, 17B
Is joined to a gas flow path 18 provided on the wall surface of the die 10 on the side of the extrusion port 15. These gas injection ports 17A, 17B
Are arranged so that one gas injection port 17A and the other gas injection port 17B are shifted so as not to cancel each other's wind pressure when gas is injected from two directions.

The gas can be injected in a time-division manner. That is, when the gas is injected from one gas injection port 17A, the gas may not be injected from the other gas injection port 17B.

The gas injection ports 17A and 17B may be configured such that the gas injection ports 17A and 17B are movable so that the injection angle can be adjusted so that the gas can be blown to a specified portion of the die lip 16 or the gas injection port. Mouth 17A, 17B
May be opened and closed to adjust the gas flow rate.

Next, as shown in FIG. 5, the die 10 has annular extrusion ports 15 arranged in a line.
The gas injection ports 17A and 17B for injecting gas are respectively provided above and below the extrusion port 15 for each case.

A gas inlet 19 for taking in gas from the outside is provided on the wall surface of the die 10 on the side of the extrusion port 15, and the inlet 19 is connected to a gas supply source such as a cylinder or a pump for sending gas. They are joined via a hose 20 or the like.

Next, as shown in FIG. 6, the extrusion port 15 of the die includes an annular extrusion port 15 for extruding the molding material, and a die lip 16, and gas injection ports disposed above and below the extrusion port 15. 17A and 17B have a tapered shape tapering toward the gas outlet.

The molding material 31 extruded by the screw 34 of the extruder 30 flows into the die 10 from the inlet 11 of the die mounted on the tip of the extruder 30, passes through the guide path 12 of the die 10, and forms a mold. And extruded from the extrusion port 15.

At this time, gas is injected from the gas injection ports 17A and 17B provided in the die 10, and the material to be attached to the die lip 16 is removed by wind pressure. Here, the gas may be injected continuously or intermittently during the operation of the extrusion, or may be injected intermittently every time the extrusion is stopped at regular intervals.

The gas flow rate is represented by a value obtained by dividing the gas flow rate by the cross-sectional area of the gas flow path provided in the die.
Adjustment is possible in the range of 0 m / sec. The gas flow rate may be adjusted by a method of restricting the valve of the gas supply source, or by providing a valve in the middle of the hose 22 or the like and opening and closing the valve.

The molding material 31 is extruded in the form of a strand (thin wire rod) by a die, then cooled by water or hot water, taken up by a take-off machine, and then cut by a cutter or the like to obtain a granular material. Obtain pellets.

[0054]

According to the extrusion molding method and the die according to the present invention, the trouble that a part of the material separated from the surface of the molded article adheres to the die lip can be greatly reduced.

Therefore, these are hardly attached to or mixed with the molded product, and a product having a desired shape can be obtained without impairing the appearance of the product. In addition, since the temperature of the surface of the molded product is reduced by the injection of gas, the occurrence of oxidation or burning is suppressed.

Further, the number of cleaning operations on the die surface can be reduced, or the cleaning operation time can be reduced, so that the production efficiency can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a die according to a first embodiment.

FIG. 2 is a front view of a die according to the first embodiment.

FIG. 3 is a front view of an extrusion port and an airflow injection port of the die according to the first embodiment.

FIG. 4 is a cross-sectional view of a die according to a second embodiment.

FIG. 5 is a front view of a die according to the second embodiment.

FIG. 6 is a front view of an extrusion port and an airflow injection port of the die according to the second embodiment.

FIG. 7 is a cross-sectional view of the extruder according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Die 2 ... Inflow port 3 ... Guideway 4 ... Extrusion port 5 ... Gas injection port 6 ... Gas injection port 7 ... Die lip 8 ... Gas flow path 10 ... Die 11 ... Inflow port 12 ... Guide path 15 ... Extrusion port 16 ... Die lip 17 ... Gas injection port 18 ... Gas flow path 30 ... Extruder 32 ...・ Hopper 33 ・ ・ ・ Heating cylinder 34 ・ ・ ・ Screw 35 ・ ・ ・ Die 39 ・ ・ ・ Heater

Claims (6)

[Claims] 1. When a molding material melted by an extruder is extruded from an extrusion port of a die attached to a tip of the extruder, a gas is injected from around the extrusion port of the die toward a die lip. Extrusion molding method. 2. The flow rate of the gas is 0.1 to 20 m / sec.
2. The extrusion molding method according to claim 1, wherein the extrusion molding method is c. 3. The extrusion molding method according to claim 1, wherein the molded product is a strand or a fibrous material. 4. A die for extrusion molding, wherein a gas injection port communicating with a gas supply source is formed around an extrusion port of the die. 5. The extrusion die according to claim 4, wherein the gas injection port is provided continuously or intermittently around the extrusion port. 6. The extruder is detachable from the extruder, and is formed on the die attachment side to receive a molding material extruded from the extruder, and from the inflow side to the extruder side. A guide path communicating with and guiding the molding material;
At least one extrusion port for extruding the molding material guided through the guide path, a die lip formed on the extrusion side section to determine the shape of the extrusion port, and a gas injection port for injecting gas toward the die lip portion, The extrusion die according to claim 4 or 5, wherein a molding material is molded or laminated in a desired shape in the guide path.