JP2001279522A - High melting point monofilament and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high melting point monofilament having excellent uniformity of filament diameter and tensile strength, useful as an industrial material and to provide a method for efficiently producing the same. SOLUTION: This high melting point monofilament comprises a thermoplastic resin having >=280 deg.C melting point and >=90 deg.C glass transition point and has >=0.05 mm diameter, <=4% coefficient of variation of filament diameter in the length direction and <=6% coefficient of variation of tensile strength measurement values of 50 times. The monofilament is produced by a method for cooling and solidification in a mist atmosphere having a specific temperature and specific volume median particle diameter ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monofilament made of a thermoplastic resin having a high melting point and a high glass transition point, and a method for producing the same. High-melting point monofilament useful as a material and an efficient production method thereof.

[0002]

2. Description of the Related Art In recent years, thermoplastic resins having an extremely high melting point (hereinafter abbreviated as Tm) and a high glass transition point (hereinafter abbreviated as Tg) have been required due to the demand for heat resistance and thermal dimensional stability. Developed and marketed for industrial materials. And since these thermoplastic resins can employ | adopt the relatively easy melt-spinning method as a fiberization means, they are especially noted as resin for super heat resistant fibers.

However, a melt spinning cooling method in the production of monofilaments composed of these thermoplastic resins is, for example, the production of general-purpose thermoplastic resin monofilaments having a relatively low Tm and low Tg, as typified by JP-A-11-93015. When the applied liquid bath cooling method is adopted, the molten extruded filaments are kept at Tg or more,
When immersed and cooled in a liquid bath of Tg or less and cooled, the filaments in the cooling bath cause meandering shaking and become inferior to linear irregularities, and also cause stretching irregularities in a subsequent stretching process. Therefore, there is a problem that only a monofilament having a large unevenness in strength can be obtained.

Although the cause of such a problem is not clear, the liquid bath cooling is rapid cooling, and the Tg of the resin is high.
Is high, a temperature difference occurs between the inner and outer layers of the melt-extruded filaments that have entered the liquid bath, resulting in non-uniform cooling shrinkage, and further, the filaments cooled to Tg or less are solidified into a glass. Therefore, it is considered that the resistance force of the guide in the cooling bath or the like cannot be absorbed, and as a result, the filaments meander. In this case, if the cooling bath temperature is equal to or higher than Tg, meandering does not occur, but in the production of high Tm and high Tg monofilaments, both equipment and operation become complicated,
It is extremely difficult to adopt this method.

On the other hand, as a mild cooling method, for example, Japanese Patent Publication No. 3-62803 describes an air cooling method. When this method is applied to ultra-high melting point resin, the gap between the molten resin temperature and the air temperature increases, and the cooling effect is relatively improved. Molding is also possible, and it can be said that solidification molding alone is an effective means.

However, in this air cooling method, since the specific heat of air is small, a long cooling zone must be provided to perform sufficient cooling and solidification. Slow gradual cooling has a problem that drawability is impaired because crystallization of undrawn yarn progresses to a high degree, and as a result, only monofilaments having poor physical properties and large physical property irregularities can be obtained.

[0007] As a compromise method described above, a method in which a melt-extruded filament is passed through a heating cylinder under specific conditions and then cooled in a liquid bath (Japanese Patent Application Laid-Open Nos. 2-234913 and 4-4-2).
343710) and a cooling method in which the difference between the surface temperature of the monofilament after spinning and the cooling temperature is specified (Japanese Patent Laid-Open No.
No. 157917). The main purpose of these methods is to pursue high mechanical characteristics represented by knot strength, and it can be said that a certain effect has been obtained in this respect. Japanese Patent Application Laid-Open No. 4-343710 also discloses, as another object, the circularity of a monofilament and the effect of preventing cooling voids.

[0008] In these compromised methods, if the conditions of immersion in a liquid bath after cooling the melt-extruded filaments to Tg or less in the gas cooling zone are not likely to occur, the meandering in the bath is unlikely to occur, and compared with the above-mentioned air cooling alone method. If this is done, the spots of linearity and spots of tensile strength will be improved. However, to significantly cool the extruded filaments to Tg or less by gas cooling,
Although not as good as the gas-cooled-only method, it was also unsatisfactory because it still required a long cooling zone and tended to suffer the same disadvantages as the mild air-cooled-only method. Conversely, when the extruded filaments are immersed in a liquid bath in a state of Tg or more, the same problem as liquid bath cooling occurs, especially when applied to high Tm and high Tg polymers, since the tendency is remarkable. It was not enough.

[0009]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying to solve the problems in the prior art described above.

Accordingly, it is an object of the present invention to provide a high melting point monofilament which is excellent in the uniformity of the warp and tensile strength and is useful for industrial materials, and an efficient production method thereof.

[0011]

In order to achieve the above object, the high melting point monofilament of the present invention has a melting point of 28%.
It is a monofilament made of a thermoplastic resin having a glass transition point of 90 ° C. or more and a temperature of 90 ° C. or more, and a diameter of 0.05 mm or more. 4% or less, and the variation rate of the measured value of the tensile strength 50 times (hereinafter abbreviated as Tcv%) is 6%.
It is characterized by the following.

Further, the method for producing a high melting point monofilament of the present invention is characterized in that a thermoplastic resin having a melting point of 280 ° C. or more and a glass transition point of 90 ° C. or more is melt-extruded from a spinning nozzle as a filament, and then extruded. Within 0.5 to 13 seconds, the melt-extruded filament has a volume median particle diameter (hereinafter abbreviated as MVD) of 1/1/1 of the outer peripheral length of the melt-extruded filament. The method is characterized in that the molten extruded filament is cooled and solidified by introducing into a mist atmosphere of 10 or less.

In the present invention, the MVD is a particle diameter at which a total particle volume of a large particle group is equal to a total particle volume of a small particle group when a certain particle group is divided into a large particle group and a small particle group. It is. Further, the fluctuation rate is JIS-Z8101-1: 1.
This is a value obtained by multiplying the variation coefficient defined by 999 by 100.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The polymer constituting the monofilament of the present invention may be any thermoplastic resin having a Tm of 280 ° C. or more and a Tg of 90 ° C. or more, and particularly a polyether represented by the following general formula [I]. Ether ketone (hereinafter abbreviated as PEEK), polyether nitrile (hereinafter abbreviated as PEN) represented by the following general formula [II], and polyimide (hereinafter PI) represented by the following general formula [III] ) And polyphenylene sulfide (hereinafter abbreviated as PPS) represented by the following general formula [IV] are preferably used.

[0016]

Embedded image

[0017]

Embedded image (However, Ar in the formula has 6 to 20 carbon atoms, has an aromatic ring in the main chain, and represents a divalent group represented by the following formula.)

[0018]

Embedded image

[0019]

Embedded image

[0020]

Embedded image In addition, the thermoplastic resin constituting the monofilament includes:
A small amount of titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin, zirconic acid, etc., various inorganic particles, crosslinked polymer particles, various metal particles, and other conventionally known antioxidants Agents, sequestering agents, ion exchange agents, anti-coloring agents, light-fast agents, flame retardants, various colorants, antistatic agents, waxes, silicone oils, various surfactants, various reinforcing fibers, various plasticizers, etc. May be added.

The monofilament made of the high Tm and high Tg thermoplastic resin of the present invention is a continuous yarn made of one single yarn and has a diameter of 0.05 mm or more. When the monofilament diameter (hereinafter, abbreviated as the yarn diameter) is less than the above range, cooling proceeds even before being guided into the mist by the production method of the present invention, and as in the case of the gas cooling method, linear spots and tensile strengths occur. It is inferior to spots. There is no particular upper limit on the yarn diameter, but as the melt-extruded filament becomes thicker, a temperature gradient occurs in the inner and outer layers of the filament, the crystal spots of the undrawn yarn are enlarged, and the drawability tends to be hindered. Therefore, it is difficult to obtain a monofilament having high tensile strength. Although the yarn diameter can be appropriately selected depending on the application, it is usually 0.
The range of 05-5.0 mm is most often used.

The monofilament comprising the high Tm and high Tg thermoplastic resin of the present invention may have any cross-sectional shape such as a circle, a triangle, a square or a polygon, and may be a composite monofilament with another thermoplastic resin. There may be. In this case, the yarn diameter is represented by an equivalent diameter determined by the following equation (1).

Deq = 4 A / U (1) where Deq: equivalent diameter (mm) A: cross-sectional area of monofilament (mm ² ) U: outer peripheral length of monofilament cross section (mm) High melting point monofilament is Dcv%
Is as small as 4% or less per 100 m, and Tcv% is 6%.
% And a new characteristic as small as less than 10%.

The high melting point monofilament of the present invention having such properties can be produced by the following method.

The production of the monofilament comprising the high Tm and high Tg thermoplastic resin of the present invention is carried out in the following manner.
And, after melting and extruding a thermoplastic resin having a Tg of 90 ° C. or more from a spinning nozzle by a known method using a spinning machine equipped with a high-temperature compatible heater, the extruded filament is cooled and solidified under specific conditions, Next, the method of stretching by a conventional method and, depending on the required properties, the method of heat setting is the main point. The optimum conditions of this cooling method will be described below.

First, the melt-extruded filaments are extruded from the spinning nozzle, and after 0.5 seconds to 13 seconds, preferably 1 second.
It is necessary to guide into the mist within 10 seconds to 10 seconds. Time to pass through the air before being guided into this mist (hereinafter,
Ta is abbreviated as short as possible; however, if it is less than the above range, the surface of the monofilament is roughened and the stretchability is inferior. vice versa,
Exceeding the above range is not preferable because the air zone becomes longer and the same problems as in the gas cooling method occur.

The mist temperature is from 0 ° C. to 100 ° C., preferably from 20 ° C. to 80 ° C. When the MVD ratio of the mist described later is within the range of the present invention, the mist is rapidly cooled even if the MVD ratio described below is within the range of the present invention. Conversely, when the ratio exceeds the above range, the surface properties of the monofilament are not only inferior, but also the apparatus and steps become complicated, which is not preferable. Although the reason for this is not clear, it is considered that the monofilament becomes high in temperature due to insufficient cooling, and is likely to be damaged or crushed by contact with the take-off roller or guides.

The particle size of the mist used for cooling in the present invention is as follows:
It is extremely important that the ratio of the MVD of the mist to the outer peripheral length of the melt-extruded filament (MVD ratio) needs to be 1/10 or less. If the MVD ratio exceeds the above-mentioned range, as in the case of cooling in a liquid bath, it is not preferable because the spots of linearity and spots of physical properties tend to deteriorate. The smaller the MVD, the more
However, when the MVD ratio is 1/2000 or less, the cooling tends to be insufficient. Preferably it is in the range of 1/100 to 1/1000.

It is sufficient that the cooling time by the mist is 2 seconds or more, but a range of 5 seconds to 30 seconds is preferably applied.

As a method of applying mist to the molten filament,
A method of passing through a box equipped with a mist generator, a method of directly spraying mist from several mist nozzles to a traveling molten filament can be considered, as long as the above condition range is satisfied, any method may be used. Can be adopted.

As the mist cooling medium, any liquid can be used as long as it can be easily removed from the surface of the monofilament and does not substantially change the physical and chemical properties of the monofilament.
A cooling medium such as water, ethylene glycol, paraffin and glycerin is preferred from the viewpoint of high specific heat, high cooling efficiency and economical efficiency.

The undrawn monofilament formed by cooling and solidifying is then drawn in one or more stages at a temperature of Tg or more according to a conventional method. Further, depending on the required characteristics, it is heat-set by tension or relaxation and wound up.

The high melting point monofilament of the present invention thus obtained has a Dcv% of 4% or less and a Tcv% of 6%.
As described below, since the particles have small irregularities and uniform physical properties, they can more effectively utilize the excellent property of super heat resistance, and are extremely useful as monofilaments for industrial materials.

Industrial materials to which the high melting point monofilament of the present invention can be applied include brushes, wire materials such as ropes and tension wires, rubber reinforcing materials and filters, belt conveyors, papermaking tools, and fabrics such as meshes. Can be mentioned.

[0035]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

The measurement and evaluation of each characteristic in the following examples were performed according to the following criteria. (1) Mist temperature The sensor of the thermocouple type thermometer was directly inserted into the mist atmosphere and measured. (2) MVD Measured by MASTER Sizer-S manufactured by Malvern, UK. (3) Dcv% A monofilament having a length of 100 m is randomly distributed for 60 to 7 days.
0, cut perpendicular to the fiber axis, take a cross-section of them with a microscope enlarged photograph, measure the yarn cross-section diameter of 50 of them, calculate the variation coefficient according to JIS-Z8101-1: 1999, Multiplied by 100. (4) Tcv% The coefficient of variation of the tensile strength data measured repeatedly 50 times by the standard test method of the tensile strength specified in JIS L1013 was calculated according to JIS-Z8101-1: 1999, and multiplied by 100. [Example 1] PEEK having Tm of 340 ° C and Tg of 143 ° C
(“Peek450G” manufactured by VICTREX, UK) was melted at 375 ° C. with an extruder by a conventional method, passed through a filtration layer in a spinning pack via a gear pump, and was applied to a molten filament spun from a nozzle by spraying system Japan ( A water mist sprayed from a SUJF1 nozzle was directly sprayed, cooled, solidified, and wound up.
The mist spray cooling time at this time was 20 seconds.
Next, the wound undrawn yarn is drawn 3.0 times in a hot air drying and heating furnace at 200 ° C., and further heat-fixed at a constant length in a hot air drying and heating furnace at 300 ° C., yarn diameter: 0.5 mm, tensile strength : 4.6c
N / dtex PEEK monofilaments were produced.
At this time, Ta, the temperature of the water mist, the MVD ratio, and the evaluation results of Dcv% and Tcv% of the obtained monofilament are also shown in Table 1. Example 2 PEN having a Tm of 340 ° C. and a Tg of 145 ° C. (“Idemitsu PEN-RF” manufactured by Idemitsu Petrochemical Co., Ltd.) was melted at 370 ° C. by an extruder by a conventional method, and passed through a filtration layer in a spin pack through a gear pump. After spinning out from a nozzle and mist cooling under the same conditions as in Example 1, stretched 3.0 times in a hot air drying and heating furnace, and further heat-fixed at a constant length in a 300 ° C. hot air drying and heating furnace to obtain a yarn diameter of 0. 0.5 mm, tensile strength: 4.0
A cN / dtex PEN monofilament was produced.
Table 1 shows the evaluation results of Ta, mist temperature, MVD ratio and Dcv% and Tcv% of the obtained monofilament at this time.
It was also described in. Example 3 PI having a Tm of 388 ° C. and a Tg of 250 ° C. (“AURUM PL500” manufactured by Mitsui Chemicals, Inc.) was melted at 410 ° C. by an extruder by a conventional method, passed through a gear pump, passed through a filtration layer in a spinning pack, and passed through a nozzle. The molten filament was solidified by cooling under the same conditions as in Example 1 except that the spinning time and the mist spraying time were 30 seconds, and the wound filament was wound.
Next, the wound undrawn yarn is drawn 3.0 times in a hot-air drying oven at 255 ° C., and is heat-fixed at a constant length in a hot-air drying oven at 300 ° C. to have a diameter of 0.5 mm and a tensile strength of: 3.8cN
/ Dtex PI monofilament was produced. At this time, Ta, the mist temperature, the MVD ratio and the evaluation results of Dcv% and Tcv% of the obtained monofilament are also shown in Table 1. Example 4 PPS having a Tm of 285 ° C. and a Tg of 93 ° C. (“RITON E2080” manufactured by Toray Industries, Inc.) was melted to 330 ° C. by an extruder by a conventional method, and was spun from a nozzle through a filtration layer in a spinning pack via a gear pump. broth,
Except that the mist spraying time was 10 seconds, the molten filament was solidified by cooling under the same conditions as in Example 1 and wound up. Then, the wound undrawn yarn is stretched to the first stage 3.0 times in a hot air drying oven at 100 ° C., and then subjected to the second stage stretching 1.5 times in a hot air drying oven at 150 ° C. Furthermore, 3% relaxation heat fixation was performed in a hot air dry heat furnace at 170 ° C., and the diameter was 0.5 m.
m, a PPS monofilament having a tensile strength of 3.9 cN / dtex was produced. At this time, Ta, mist temperature, MV
D ratio and Dcv% of the obtained monofilament, Tc
Table 1 also shows the evaluation results of v%. [Example 5] Under the same conditions as in Example 1, except that the spinneret was changed, the long side: 0.6 mm and the short side: 0.4
mm, equivalent diameter: PE with a rectangular cross section of 0.48 mm
An EK monofilament was manufactured. The tensile strength of the obtained PEEK monofilament was 4.5 cN / dtex. At this time, Ta, the mist temperature, the MVD ratio and the evaluation results of Dcv% and Tcv% of the obtained monofilament are also shown in Table 1. [Example 6] In Example 1, when the yarn diameter was changed to 6 mm, breakage occurred sporadically in the first-stage drawing at 3.0 times, so the PEEK monofilament was changed to the first-stage drawing ratio of 2.7 times. Was manufactured. The tensile strength of the obtained PEEK monofilament was 4.0 cN / dtex. At this time, Ta, the mist temperature, the MVD ratio and the evaluation results of Dcv% and Tcv% of the obtained monofilament are also shown in Table 1. [Example 7] In Example 1, the mist device was adjusted,
MVD of 1.2 μm (melt extruded filament outer circumference ratio, about 1
/ 2267), the first drawing nip roller caused the yarn to be crushed, and the roundness was slightly reduced. At this time, Ta, mist temperature, MVD ratio and Dcv% of the obtained PEEK monofilament,
The evaluation results of Tcv% are also shown in Table 1. In addition, PEEK
The tensile strength of the monofilament was 4.7 cN / dtex. [Comparative Example 1] In Example 1, the yarn diameter was 0.04 mm.
However, since the so-called knotted yarns were frequently generated in which undrawn portions were mixed in the drawn yarn and the quality was inferior, Dcv% and Tcv of the obtained PEEK monofilament were obtained.
The evaluation of% was discontinued. [Comparative Example 2] In Example 1, when Ta was changed to 0.4 seconds, the yarn was frequently broken in the stretching step, so that PEEK was used.
Production of monofilaments was discontinued. Comparative Example 3 A PEEK monofilament was manufactured under the same conditions as in Example 1 except that Ta was set to 20 seconds. At this time, Ta, the mist temperature, the MVD ratio and the evaluation results of Dcv% and Tcv% of the obtained monofilament are also shown in Table 1. [Comparative Example 4] A PEEK monofilament was produced under the same conditions as in Example 1 except that ethylene glycol was used as a mist cooling medium and the mist temperature was set to -3 ° C. At this time, Ta, the mist temperature, the MVD ratio and the evaluation results of Dcv% and Tcv% of the obtained monofilament are also shown in Table 1. Comparative Example 5 A PEEK monofilament was produced under the same conditions as in Example 1 except that a paraffin solution was used as a mist cooling medium and the mist temperature was set to 120 ° C. T at this time
Table 1 also shows a, the mist temperature, the MVD ratio, and the evaluation results of Dcv% and Tcv% of the obtained monofilament. [Comparative Example 6] In Example 1, the mist device was adjusted,
When the MVD ratio was reduced to 1/5, it was observed that chatter occurred in the guide in the cooling zone, and that the yarn sway propagated to the die extruding portion. Table 1 also shows the evaluation results of Ta, mist temperature and Dcv% and Tcv% of the obtained monofilament at this time. Comparative Example 7 A PEEK monofilament was produced under the same conditions as in Example 1 except that the molten extrudate was cooled by being introduced into a 25 ° C. water bath. Although the meandering in the water bath was severe and it was extremely difficult to pick up, a small amount of PEEK monofilament could be obtained. Table 1 also shows the evaluation results of Dcv% and Tcv% of the obtained monofilament. [Comparative Example 8] In Example 1, when the melt extruded product was cooled with air at 20 ° C, a 6 m air-cooling distance was required until the running yarn temperature reached 100 ° C or lower, and the running yarn sway was large. Was observed. Further, at the time of stretching, since the number of thread breaks frequently occurs, the stretching ratio at which stable stretching can be performed is 2.3 times or less, and the strength of the obtained PEEK monofilament is 2.1.
It was as low as cN / dtex. Table 1 shows the evaluation results of Dcv% and Tcv% of the obtained monofilament.
It was also described in.

[0037]

[Table 1]

[0038]

As described above, the high-melting point monofilament of the present invention has small linear spots and uniform physical properties, so that it can more effectively utilize the excellent property of super heat resistance. It is extremely useful as a monofilament for industrial materials.

According to the method for producing a high melting point monofilament of the present invention, a high melting point monofilament having the above-mentioned characteristics can be efficiently produced by employing mist cooling means.

Continued on the front page (72) Inventor Shuhisa Hyodo 1 Kawara, Showa-cho, Okazaki City, Aichi Prefecture Toray Monofilament Co., Ltd. F-term (reference) 4L035 BB31 BB54 BB79 BB89 BB91 CC02 CC09 DD14 EE01 EE08 FF01 MC04 MD01 MF02 4L045 AA05 BA02 DA10 DA19

Claims (8)

[Claims] 1. A thermoplastic resin having a melting point of 280 ° C. or more and a glass transition point of 90 ° C. or more, and having a diameter of 0.05
mm or more, the linear filament variation rate in the longitudinal direction is 4% or less per 100 m, and the tensile strength is 50% or less.
A high melting point monofilament characterized in that the rate of change of the measured value is 6% or less. 2. The high melting point monofilament according to claim 1, wherein the thermoplastic resin constituting the monofilament comprises a polyetheretherketone having a repeating unit represented by the following general formula [I]. Embedded image 3. The high melting point monofilament according to claim 1, wherein the thermoplastic resin constituting the monofilament comprises a polyether nitrile having a repeating unit represented by the following general formula [II]. Embedded image (However, Ar in the formula has 6 to 20 carbon atoms, has an aromatic ring in the main chain, and represents a divalent group represented by the following formula.) 4. The high melting point monofilament according to claim 1, wherein the thermoplastic resin constituting the monofilament comprises a polyimide having a repeating unit represented by the following general formula [III]. Embedded image 5. The high melting point monofilament according to claim 1, wherein the thermoplastic resin constituting the monofilament is made of polyphenylene sulfide having a repeating unit represented by the following general formula [IV]. Embedded image 6. A thermoplastic resin having a melting point of 280 ° C. or higher and a glass transition point of 90 ° C. or higher is melt-extruded from a spinning nozzle as a melt-extruded filament, and the melt-extruded filament is heated for 0.5 seconds. Within 13 seconds or more, 0 ° C. or more and 100 ° C. or less, and the volume median particle diameter is guided into a mist atmosphere of 1/10 or less of the outer peripheral length of the melt-extruded filament, and the mist guides the melt-extruded filament. The method for producing a high melting point monofilament according to claim 1, wherein the monofilament is cooled and solidified. 7. The method for producing a high melting point monofilament according to claim 6, wherein the mist atmosphere is formed by spraying mist from a mist nozzle onto a melt-extruded filament. 8. The mist atmosphere is formed from a box provided with a mist nozzle.
3. The method for producing a high melting point monofilament according to item 1.