JPS61194204A - Spinneret - Google Patents

Abstract

PURPOSE:To carry out the spinning of filament from a polymer having high molecular weight preventing the thermal decomposition nd melt fracture of the polymer, by protruding a spinning nozzle beyond a heating fie, and passing electric current along the longitudinal direction of the capillary to effect the generation of Joule heat. CONSTITUTION:The terminals of the electric source 15 are connected to the tip end 14-2 of the spinning nozzle 14 and a part 13-2 of the heating die 13, and the nozzle is heated at a high temperature by the Joule heat generated by the electric current. The temperature of the nozzle is detected by the tempera ture sensor 16, and the electric current is controlled by feeding back the tempera ture signal to the variable transformer in the electric source 15. The average outer diameter (D) of the nozzle protruded from the heating die is <=10mm, and the ratio of D to the average diameter (d) of the capillary 14-1 (D/d) is 2-10.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a new and useful spinneret apparatus suitable for spinning uniform filaments from polymers with high melt viscosity.

b. Prior Art It is generally well known that when it comes to the same polymer, those with higher molecular weights can produce fibers with superior mechanical properties such as strength and fatigue resistance compared to those with lower molecular weights. However, as the molecular weight of the polymer increases, the melt viscosity also increases, which not only makes extrusion itself difficult;
When the polymer is discharged from the capillary (tubule) of the spinneret, an unstable phenomenon called melt fracture may occur, making stable fiber formation impossible.

In order to prevent the melt fracture phenomenon, (1) increase the melting temperature to lower the viscosity, (2) reduce the discharge speed of the polymer, and (3) adjust the angle of inflow of the polymer into the capillary of the mouthpiece (inlet angle). Means such as (4) increasing the capillary length (land length) are known.

In the above, (1) is the simplest method, but as long as a conventional spinneret device is used, the problem of thermal decomposition of the polymer cannot be avoided due to the residence time of the polymer in the spinneret. For example, ultra-high molecular weight polyethylene (UHMW-PE) with a molecular weight on the order of 1 million, or polyethylene terephthalate (high [η]
Polyesters such as PET) and poly-β-hydroxybutyric acid (PH8), or fully aromatic polyamides such as polymetaphenylene isophthalamide (PMIA) whose melting point and thermal decomposition point are close even if the molecular weight is on the order of magnitude. cannot be applied to

Means (2) above is not practical because it significantly sacrifices productivity. The above means (31, (4)) are important in setting the shape of the capillary part in the mouthpiece, and are effective to some extent, but according to the experimental results of the present inventor, the above-mentioned polymer As long as it is targeted, it will not be an essential solution.

Therefore, the conventional fiberization methods commonly used for the above-mentioned polymers are solution spinning, which involves dissolving the polymer in an appropriate solvent and then molding it, or plasticizing, which involves mixing a large amount of plasticizer and melt-molding it. It was chemically spun.

However, such means not only require large amounts of solvents and plasticizers, but also require complicated equipment for their recovery, which inevitably increases production costs.

Regarding the above solution method, whether it is a wet method or a dry method,
Since a large amount of solvent must be removed from the fibrous material after spinning, it is extremely difficult to produce filaments with a large denier, such as 100 DE or more. The plasticized spinning method also has similar drawbacks insofar as the plasticizer is removed.

Therefore, in order to produce thick denier filaments of the above-mentioned polymers at low cost, it is necessary to develop a special melt spinning means.

By the way, one of these special melt spinning methods and devices is
One example is the invention described in Japanese Unexamined Patent Publication No. 144607/1987, which was proposed by the present inventor together with other inventors. That is, in this proposal, a flat polymer molded product is pushed into a preheating die by a pushing means such as a pushing roller, and is instantaneously melted by electrical heating of a mesh-like spinneret installed at the tip of the die. A fiber aggregate is produced by extruding a polymer through a large number of slits in a die to form a large number of fibrous rivulets.

The above invention aims to spin several hundred to tens of thousands of fibers at the same time from one spindle, and it is called the spinneret. Way 1.71. %
do not have.

On the other hand, with regard to the above-mentioned special polymers, there has been an increasing need for monofilaments, mainly large deniers, for use in industrial materials, medicine, and the like.

Therefore, based on the experience of the invention described in JP-A-59-144607, the present inventor conducted extensive research in order to develop a technique for melt-spinning monofilaments from the above-mentioned special polymer.

C6 Purpose of the Invention The purpose of the present invention is to produce monofilaments from polymers with high molecular weight (which are considered difficult to melt-spun using conventional spinneret equipment) by a melt-spinning method while preventing thermal decomposition and melt fracture. The objective is to provide a spinneret device suitable for.

Another object of the present invention is to provide a spinneret device suitable for spinning uniform thick denier monofilaments from polymers that have conventionally been considered difficult to melt spin due to their close melting points and thermal decomposition points. There is a particular thing.

Still another object of the present invention is to provide a spinneret device suitable for spinning uniform monofilaments even from ordinary melt-spinning polymers by uniformizing the melt flow of the polymer in the spinneret capillary. It's about doing.

Yet another object of the present invention is to provide a spinneret device suitable for producing monofilaments with latent crimp properties.

Still another object of the present invention is to provide a spinneret device suitable for producing multifilaments composed of monofilaments with different properties from the same spinneret.

Further objects of the invention will become apparent from the detailed description below.

d0 Structure of the Invention According to the research of the present inventor, the object of the present invention is to provide a spinneret having a spinning nozzle having at least one capillary therein protruding from a heating die, which This is achieved by a spinneret device characterized in that a current supply device is connected to the nozzle to generate Joule heat by passing a current in the length direction of the capillary.

The spinneret device of the present invention is further improved by setting the ratio (U/d) of the length (l) of the capillary to the average diameter (d) of the spinning nozzle protruding outside the heating die to at least 5. It can be said that it is effective.

Further, in the spinneret device of the present invention, the cross-sectional area of the nozzle may be changed along the length of the spinning nozzle protruding outside the heating die in order to change the temperature along the length of the spinning nozzle. At least two nozzles with different electrical resistances
It is effective to use different metals and combine them in a block shape in the length direction.

Furthermore, in the spinneret device of the present invention, the spinning nozzle protruding outside the heating die is constructed by combining at least two types of metals having different electrical resistances in a block shape in the radial direction; It is also an effective means to set the center of the capillary inside the nozzle eccentrically from the center of the spinning nozzle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure 1 of the spinneret device of the present invention, its functions, possible ranges, etc. will be explained in more detail below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of a spinning device for producing monofilaments from a high melt viscosity polymer using the spinneret device of the present invention.

Conventionally known melt spinning equipment is mainly composed of a polymer melting and quantitative supplying device and a spinneret device, and the spinneret device of the present invention is also composed of a conventional melting and quantitative supplying device, that is, a silver plate melter, a gear pump, or an extractor. It can be used as a melt spinning device in combination with a ruler and a gear pump, but for polymers with high melt viscosity such as those mentioned above, the spinning device for which the present invention previously applied for a patent (filed on January 28, 1985) The device proposed in this specification is extremely effective and is schematically shown in FIG. Since this extrusion device uses a rod-shaped molded polymer as a spinning raw material, it is characterized in that it can reliably extrude a fixed amount of any high viscosity (high molecular weight) polymer.

The 0-shaped molded products 1 are placed in a hopper 2 in series, gripped by a supply roller 3, and supplied one after another to a front fixed cylinder 4.

The supply roller 3 is used to force the rod-shaped molded product 1 into a slimy structure of a forced rotation cylinder 5, which will be described later, and is not necessarily necessary when the rod-shaped molded product is a continuous body.

Regarding the production of the rod-shaped molded article 1, the above-mentioned polymer, which has conventionally been considered difficult to melt spin, is used, namely PMIA.
, PTFE, PVC, UHMW-PE, PH8, high [η
] Even with PET, ordinary plastic molding methods such as injection molding, ram extrusion molding, and compression molding can be easily applied to the powder itself or to the powder mixed with some plasticizer. Furthermore, in the case of conventional melt-spinning polymers, continuous or discontinuous rod-shaped molded products can be easily produced directly from the polymerization process.

The inner diameter of the front fixed cylinder 4 must be larger than the outer diameter of the rod-shaped molding 1. A protrusion 10 is provided for fixing the front part. If the rod-shaped molded product has a simple circular cross section, the tip of the protrusion 10 should have a sharp knife-like tip. Further, the number of protrusions is required to be at least one, but three is preferable in order to securely prevent rotation of the rod-shaped molded product and fix it at the center of the cylinder.

Next, the rod-shaped molded product 1 passing through the front fixed cylinder 4 reaches a rotating cylinder 5 coaxially installed immediately after the front fixed cylinder. This rotating cylinder 5 is supported by upper and lower bearings 6.7, and is forcibly rotated by a motor (not shown in the drawing) connected to a sprocket 8 fixed to the cylinder. The inside of this rotary cylinder 5 has a slimy structure with a smaller diameter than the inner diameter of the front fixed cylinder, but in this embodiment, this slimy structure is divided into two parts. That is, the first slime structure portion 5-1 (the inside of the rotary cylinder on the tip side) has a threaded die type structure.

This thread-cutting die type structure is basically the same as a tool for cutting J5 threads in ordinary round metal bars.

A second slime structure 5-2 is formed next to the first slime structure 5-1. This second slime structure does not need to be a threaded die type structure, but it is sufficient as long as it is a normal slime structure and the dimensions (standards) of the slime are the same as the first slime structure. .

When a rod-shaped molded product enters the rotary cylinder 5 having the slime structure as described above, the molded product whose rotation is prevented by the fixed cylinder 4 is cut into the first slime structure portion 5-1, that is, threaded. Cutting edge A of die-shaped structure
While a male thread structure is forcibly formed, it progresses downward in Figure 1, and eventually reaches the second slime structure, where this slime structure and the male thread structure of the rod-shaped molding are firmly engaged. progress for sure.

Note that when the rod-shaped molded product is threaded with the first slime structure 5-1, that is, the thread cutting die, small chips are generated, but these can be removed by suction by the suction vibrator 19 shown in the upper part of FIG. .

In FIG. 1, the rod-shaped moldings, which are quantitatively fed as described above from a rotary cylinder 5, reach a rear stationary cylinder 9 which is coaxially installed immediately after the rotary cylinder. The structure of this rear fixed cylinder 9 may be substantially the same as the front fixed cylinder.

That is, the rear fixed cylinder 9 is provided with a protrusion 10' similar to the front fixed cylinder inside, and serves to prevent the rod-shaped molded product supplied from the rotary cylinder 5 from rotating. Preferably, the shape and location of this protrusion 10' is substantially the same as that of the front fixed cylinder. This is because by aligning the protrusion 10' of the rear fixed cylinder with the groove formed by the protrusion 10 of the front fixed cylinder (or a pre-formed groove), rotation of the rod-shaped molded product can be more firmly prevented. It is from.

A protrusion 10' provided on this rear fixed cylinder 9
0 When the tube-shaped molded product is a discontinuous body, when the end of the molded product passes through the protrusion 10 provided on the front fixed cylinder 4, the tip of this molded product is firmly secured by the protrusion 10' of the rear fixed cylinder. This is because if it is not fixed, it will rotate as the rotating cylinder 5 rotates and the rod-shaped molded product will not advance at all. As can be seen from this, the length of the rod-shaped molding used in the device of the present invention is at least 10
It needs to be longer than the length from the rear end to the tip of the projection 10' of the rear cylinder. Note that if the axial length of the protrusion of the front cylinder is too short, the groove of the rod-shaped molded product may be destroyed by the rotational force of the rotary cylinder 5. This tendency also occurs if the height of the protrusion is too low. This largely depends on the shear strength of the molded product and the required pushing force, i.e., the back pressure of the cap device, but the total length of the protrusions (if there are three protrusions, the total length of the three protrusions)
is at least three times the nominal diameter of the slime structure, the height of the protrusion is the effective height of the protrusion, and the protrusion is rod-shaped.
It is desirable to keep the height of λJ Gomana'IL-17 small (n also i16b1:10).If the rod-shaped molded product is a continuous body, the protrusion on the rear fixed cylinder is not necessarily necessary. .Furthermore, depending on the case, the front fixed cylinder may be omitted with only the rear fixed cylinder.

The rod-shaped molded product that has passed through the rear fixed cylinder 9 passes through a heat insulating ring 12. as shown in FIG. The heating die 13° spinning nozzle 149 is supplied to the spinneret device of the present invention, which is constituted by an energizing device 15. That is, the rod-shaped molded product, which was substantially solid in the rear fixed cylinder, is introduced into the heating die 13 and preheated to a desired temperature. For example, if it is a rod-shaped molded product made of a general melt-spinning polymer, it is sufficient to set this temperature to the melting temperature and spin it with a spinneret, but if the polymer is easily thermally decomposed or the temperature is raised to a temperature at which it decomposes, it is sufficient. In the case of polymers whose viscosity is otherwise too high to be spun, it takes too long to raise the temperature by heat conduction from the heating die wall, and thermal decomposition may occur during the heating process. The temperature should be kept at a safe temperature.

However, the polymer that is advantageously applied to the spinneret device of the present invention has a melt viscosity that is too high at a safe temperature that avoids thermal decomposition in the die, and therefore causes melt fracture when extruded from the capillary of a conventional spinneret. It is important to be aware that this will prevent stable spinning.

The rod-shaped molded product supplied to the heating die 13 is heated and plasticized to the above-mentioned safe temperature, and is then heated to the inlet section 13-1 in the die.
The capillary 1 of the spinning nozzle 14 is
4-1 and then discharged to the outside. At this time, the high viscosity polymer that is thinned in the inlet section 13-1 of the heating die 13 accumulates a large amount of elastic energy as it is thinned, so the above-mentioned melt fracture occurs in a simple spinning nozzle. However, the spinning nozzle 14 of the present invention includes a fixed transformer.

As shown in FIG. 1, a terminal from an energizing device 15 consisting of a variable transformer, a temperature detector, etc. is connected to the tip 14- of the spinning nozzle.
2 and the first part 13-2 of the heating die that fixes the spinning nozzle, so the nozzle itself is heated to a high temperature by the Joule heat generated by electricity, so the polymer passing through the capillary reduces its viscosity and accumulates elasticity. It flows through the capillary while releasing energy and is ejected without causing melt fracture.

The first point to be noted about the effects of the apparatus of the present invention is that the heating time of the polymer by the spinning nozzle (residence time in the capillary) is short.

For example, if the capillary of the spinning nozzle has a diameter of 2 m and a length of 40 mm, the heating time is only 2.5 seconds even if the discharge rate of a polymer with a specific gravity of 1 is 3 g/min. When heated for such a short period of time, there are many cases where there is almost no thermal decomposition even at temperatures that were conventionally thought to cause thermal decomposition.

This is natural considering that the thermal decomposition phenomenon is primarily a function of time. That is, according to the apparatus of the present invention, it is possible to employ high temperatures that were conventionally thought to be impossible due to thermal decomposition, reduce the viscosity, and prevent melt fracture.

The polymer flowing through the capillary of the spinning nozzle is transferred to nozzle 1.
Joule heat is generated by applying a voltage between the tip of the capillary 4 and the die 13 that fixes the nozzle, and passing a current in the length direction of the capillary. The necessary current is controlled by detecting the temperature of the nozzle with a temperature measuring element 16 and feeding it back to the variable transformer in the energizing device 15. The response of this control is extremely fast, unlike the indirect heating method.

The second point to be noted regarding the effects of the apparatus of the present invention is the behavior of the polymer flowing while being heated through the capillary in the spinning nozzle which is heated by electricity.

In other words, the polymer that flows through the inlet part 13-1 of the heating die ωJ and accumulates a large amount of elastic energy releases elastic energy in the flow process of the capillary of the spinning nozzle heated by electricity, and if only a simple temperature effect The viscosity is lowered due to the structural viscosity effect, resulting in stable flow and being discharged to the outside.

Therefore, what is important at this time is the ratio (Nl/d) of the length (s) of the nozzle portion protruding outside the die to the average diameter (d). Through experiments conducted by the present inventor, a clear stable flow effect was observed.

Further, if u/d is too large, problems arise such as the flow resistance of the capillary becoming too large and the residence time in the capillary becoming too long, resulting in a tendency for thermal decomposition. jQ/d
Although the optimum value of , varies depending on the type of polymer and manufacturing conditions, it is generally preferably in the range of 10 to 500.

The third point to be noted regarding the effects of the apparatus of the present invention is that the temperature of the spinning nozzle in the spinneret apparatus can be freely controlled with almost no influence on other parts. That is, the capacity of the spinning nozzle 14 is extremely small compared to the capacity of the heating die 13, and since it protrudes to the outside, the Joule-generated heat does not affect the temperature of the die. For this reason, in the apparatus of the present invention, it is extremely easy to heat only a specific part of the spinning nozzle to a high temperature, and this effect further enhances the feature of the apparatus of the present invention.

For example, the simplest way to heat a specific part using a simple bulb-shaped nozzle like the spinning nozzle in Figure 1 is to
This means keeping only the parts that are exposed to high temperatures warm.

In order to more actively raise the temperature to a specific part, the shape of the spinning nozzle may be made into a constricted shape as shown in FIG. That is, the electrical resistance of the constricted portion increases and the amount of heat generated at that portion increases.

With the apparatus of the present invention, it is also easy to create a gentle temperature gradient in the length direction of the spinning nozzle. This is easily accomplished by employing a spinning nozzle whose cross-sectional area varies gradually along its length, as shown in FIG. 3, for example.

In addition to changing the cross-sectional area of the spinning nozzle along the length as described above, there are other means for changing the temperature in the length direction of the spinning nozzle that protrudes outside the heating die, as shown in FIG. 4. This can also be achieved by combining at least two types of metals with different values in a block shape in the length direction.

In FIG. 4, for example, if part A is made of nickel chromium and 8 parts are made of stainless steel, part A will generate a larger amount of heat per unit length than part 8.

According to the experimental results of the present inventor, partially changing the temperature of the spinning nozzle as described above is extremely effective in melt-spinning the above-mentioned polymer, which was conventionally considered difficult to melt-spinning. It has become clear that the optimum conditions differ depending on the type of polymer, zero molecular weight, etc.

The fourth point to be noted regarding the effects of the device of the present invention is:
The advantage is that a latent crimpable monofilament can be easily produced.

Conventionally, various methods have been known for producing latent crimp filaments from a single polymer in a spinning process, but the simplest and most effective method is a method called anisotropic cooling method. That is, this method provides anisotropy of mechanical properties in the radial direction by varying the degree of cooling of the trickle of molten polymer discharged from the capillary of the mouthpiece in the radial direction of the trickle. In this method, the stronger the anisotropy of cooling, the stronger the latent crimpability is imparted, but on the other hand, the complexity of the process increases as a result of strong cooling. If there is anisotropy in the temperature of the overlapping polymer stream from the beginning, the degree of anisotropy will be further increased by cooling in accordance with the anisotropy.

Based on this idea, the inventors prototyped the following two devices and attempted experiments.

That is, the first device is the spinneret of the present invention, which is constructed by combining a spinning nozzle protruding to the outside of a heating die in a block shape in the radial direction using two types of metals having different electrical resistances, as shown in FIG. It is a device. In Figure 5, C is a metal with relatively low electrical resistance, such as brass, on the high-temperature heating side;
D is on the low-temperature heat generating side and is made of a metal with high electrical resistance such as nickel chromium.

The second device is a spinneret device of the present invention in which the capillary inside the spinning nozzle is eccentric from the center of the spinning nozzle, as shown in FIG. 6 showing a cross section of the spinning nozzle of the present invention. In such a spinning nozzle, the E side is the high temperature side due to the relationship between the Joule heat generation of the spinning nozzle and the heat radiation balance with the outside air.
According to the results of various experiments conducted by the present inventors, both the first and second devices were effective. Furthermore, the first. A prototype spinning nozzle as shown in FIG. 7 was made in combination with the second spinning nozzle, and spinning experiments were carried out. As a result, it was found that an extremely large latent crimp filament could be obtained with a small amount of cooling.

Regarding the effects of the device of the present invention, the fifth point to be noted is:
The advantage is that special multifilaments can be manufactured.

In order to manufacture multifilament using the apparatus of the present invention, a nozzle having a cross section as shown in FIG. 8, that is, a nozzle having a plurality of capillaries is installed as shown in FIG. It is sufficient to adopt either the method of installing the filaments in the heating die depending on the desired number of filaments. In the former case, it is basically the same as in the case of monofilament, but in the latter case, the temperature of each nozzle can be controlled independently. Even if the multifilament is made of a polymer, it is possible to produce a multifilament composed of monofilaments each having different physical properties.

In order to effectively exhibit the first to fifth effects above, the average outer diameter (D>) of the nozzle at the part that is immersed in flame outside the heating die should be 10 or less, and the ratio to the average diameter (d) of the capillary should be D/d should be 2 to 10. If it is too thick, the response to heat generation due to energization will deteriorate, which is not preferable.

Further, as the material for the spinning nozzle, it is desirable to use a metal that is durable even when the temperature is raised to about 500° C. in normal temperature air due to the generation of Joule heat due to electricity supply, and has a relatively large resistivity. That is, preferable materials include stainless steel, nickel chromium, iron chromium, chromel, nickel, brass, and the like.

The current supply device used in the present invention is 100V or 200V
a voltage regulator that can arbitrarily change the voltage of an AC power supply of approximately
The voltage from the voltage regulator is set to 1 to 10 to 1/100, and a transformer that can send a large current of several tens to hundreds of amperes to the spinning nozzle is used, and the temperature of the spinning nozzle is also detected. The output of the voltage regulator is kept constant at i
Preferably, the control device is configured by a control device for controlling the ll m.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a spinning device for producing monofilaments from a high melt viscosity polymer using the spinneret device of the present invention. FIG. 2 is a side view of a spinning nozzle exhibiting a constricted shape. FIG. 3 is a side view of a spinning nozzle exhibiting a shape in which the cross-sectional area gradually changes. FIG. 4 is a side view of a spinning nozzle constructed by splicing 82 types of A metals having different specific resistances in the length direction. FIG. 5 is a side view of a spinning nozzle constructed by combining two types of metals, C and D, which have different specific resistances, in a block shape in the radial direction. FIG. 6 is a sectional view of a spinning nozzle in which the capillary is eccentric from the center of the spinning nozzle. It is a cross-sectional view of a spinning nozzle configured to have a size of 1--1 buttons. FIG. 8 is a side view of a spinning nozzle with multiple capillaries. Patent Applicant Teijin Co., Ltd. Courtesy Patent Attorney 1) Hiroaki Jun 6 Figure I 10 70 1000 8th Area Procedural Amendment April 1985! Day

Claims (1)

[Claims] 1. A spinneret configured by protruding a spinning nozzle having at least one capillary inside thereof to the outside of a heating die, wherein a current is applied to the spinning nozzle in the length direction of the capillary. A spinneret device, characterized in that it is connected to an energizing device for generating Joule heat by flowing the spinneret. 2. The spinneret device according to item 1, wherein the ratio (l/d) of the capillary length (l) to the average diameter (d) of the spinning nozzle protruding outside the heating die is at least 5. 3. The spinneret device according to item 1, wherein the spinning nozzle protruding to the outside of the heating die has a cross-sectional area that varies along the length direction. 4. The spinneret device according to item 1, wherein the spinning nozzle protruding to the outside of the heating die is constructed by combining at least two types of metals having different specific resistances in a block shape in the length direction. 5. The spinneret device according to item 1, wherein the spinning nozzle protruding to the outside of the heating die is constructed by combining at least two types of metals having different specific resistances in a block shape in the radial direction. 6. The spinneret device according to item 1, wherein the capillary inside the spinning nozzle protruding to the outside of the heating die is eccentric from the center of the spinning nozzle.