JP2000096377A - Production of high density composite filament - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a high density, high strength sheath-core type composite filament capable of being produced in a good fiber forming property without generating voids around inorganic fine particles and also fluffs at the surface of the filament. SOLUTION: This method for producing a high density composite filament is to produce a sheath-core type composite multifilament composed of a core part of a polyester resin containing 20-80 wt.% inorganic fine particles and a sheath part of a polyester resin having >=1.45 intrinsic viscosity, and having >=1.45 specific gravity and >=4.2 g/d strength. In this case, the filament is obtained by melt-spinning at 200-1,000 m/sec, heating the obtained un-stretched fiber at 80-130 deg.C, then twisting the fiber plural times between a both surface heater 2 at 150-235 deg.C and a heating roller 3 at 150-235 deg.C to perform >=0.5 sec heat treatment and heat stretching, and then relaxing to wind it up.

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 composite filament having a high specific gravity and a high strength, which contains inorganic fine particles in a core portion and is suitable for fishery materials such as fishing nets.

[0002]

2. Description of the Related Art Conventionally, polyvinylidene chloride fibers used in fishing nets have a problem that they emit gases harmful to the environment when incinerated. In recent years, many fishing nets have been replaced by polyester fibers.

[0003] Polyester fiber is a synthetic fiber having a relatively large specific gravity. However, a polyester fiber having a higher specific gravity is desired in order to increase the sedimentation speed in water and to improve the shape retention of the fishing net against the tide.

[0004] In recent years, Russell net fishing nets capable of high-speed net making have become the mainstream in order to improve productivity, and polyester fibers of high strength and high specific gravity which can be used for such fishing nets have also been developed. Is desired. Various types of core-sheath type composite filaments containing inorganic fine particles having a high specific gravity in a core portion have been proposed in order to obtain a polyester fiber having a high specific gravity.

However, the drawing and heat treatment conditions for producing these composite filaments are not particularly taken into consideration, and even if the filaments can be obtained with good spinnability, the obtained filaments can be stretched around the inorganic fine particles by drawing. There is a problem that a small space (void) is generated and further, fluff is generated on the filament surface. That is, when voids are generated around the inorganic fine particles, the specific gravity is reduced by the voids even if inorganic particles having a high specific gravity are contained, and when fluff is generated on the filament surface, the quality of the filament is reduced and the strength is reduced. There was a problem that it became low.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, can be produced with good spinning properties, does not generate voids around the inorganic fine particles, and has fluff on the filament surface. An object of the present invention is to provide a method for producing a core-sheath type composite filament having no specific generation and high specific gravity and high strength.

[0007]

Means for Solving the Problems As a result of investigations to solve the above-mentioned problems, the present inventors have conducted a plurality of windings between a double-sided heater and a heating roller to continuously perform a heat stretching and a heat treatment, thereby obtaining a sufficient amount of heat. The inventors have found that the above problem can be solved by applying heat, and have reached the present invention.

That is, according to the present invention, a core portion is made of a polyester resin containing 20 to 80% by weight of inorganic fine particles, and a sheath portion is made of a polyester resin having a relative viscosity of 1.5 or more. 2. A method for producing a core-sheath composite multifilament having a spinning speed of 2 g / d or more.
After melt spinning at 00 to 1000 m / min and heating the obtained undrawn yarn to 80 to 130 ° C, the unstretched yarn is wound a plurality of times between a double-sided heater at 150 to 235 ° C and a heating roller at 150 to 235 ° C. The gist of the present invention is to provide a method for producing a high-specific-gravity composite filament, which comprises performing heat treatment and heat stretching for 5 seconds or more, and then relaxing and winding.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The present invention is a method for producing a core-sheath type composite multifilament in which a core portion is made of a polyester resin containing 20 to 80% by weight of inorganic fine particles and a sheath portion is made of a polyester resin having a relative viscosity of 1.5 or more.

As the polyester resin in the present invention, polyethylene terephthalate, polybutylene terephthalate, aliphatic polyester and copolymerized polyester mainly composed of these are used, but polyethylene terephthalate is most preferable in consideration of filament strength and economy. Further, a coloring agent such as carbon black, a matting agent, a smoothing agent, and the like may be added to the polyester resin of the core and the sheath as long as the effect is not impaired.

The polyester resin used for the sheath preferably has a relative viscosity of 1.5 or more, more preferably 1.60 to 1.75. When the relative viscosity is less than 1.5, the operability at the time of stretching is deteriorated, the strength of the obtained filament is reduced, and the filament is not suitable for high-speed netting.

The polyester resin in the core contains 20 to 80% by weight of inorganic fine particles. The inorganic fine particles have little secondary aggregation between the fine particles and are excellent in dispersibility in the polyester resin. Is used.
Specifically, various metals such as titanium, zirconium, barium, and tungsten, and compounds made of these metals are used. Among them, preferred are dispersibility in polyester resin, spinnability, stretchability and safety,
It is sedimentable barium.

The average particle size of the inorganic fine particles is 1.0 μm.
m or less, and does not substantially include particles having a particle diameter of 6.0 μm or more, and preferably has a shape close to a sphere.

The content of such inorganic fine particles is from 20 to
It must be 80% by weight. When the content of the inorganic fine particles is less than 20% by weight, it is difficult to sufficiently increase the specific gravity of the polyester resin in the core, and in order to increase the specific gravity of the polyester resin, inorganic fine particles having a higher specific gravity are used. When used, the difference from the specific gravity of the polyester resin to be used becomes too large, and peeling tends to occur. On the other hand, when the content exceeds 80% by weight, the processability in producing the polyester resin composition is remarkably reduced, and a composition having a uniform specific gravity cannot be obtained. It becomes difficult to obtain a filament.

The ratio between the core and the sheath is not particularly limited, but the specific gravity of the entire filament is 1.45 or more with the content of the inorganic fine particles as described above. It is preferable that the part / sheath part be 20/80 to 70/30.

The manufacturing method of the present invention will be described with reference to the drawings. FIG. 1 is a process chart showing one embodiment of the production method of the present invention. First, the polyester resin constituting the core and the sheath is spun at a spinning speed of 200 to 1000 using a composite spinning apparatus.
It is melt spun at m / min to obtain an undrawn multifilament.

The spinning temperature is 230 to 350 ° C.,
The temperature is preferably set to 50 to 310 ° C. If the spinning temperature is too low, it is difficult to completely melt, and if the spinning temperature is too high, thermal decomposition of the polymer tends to occur.

Then, the spun filaments are
It is cooled and solidified by blowing gas (air) at a temperature of not more than 10C, preferably 10 to 90C. If the cooling temperature is too low, it is difficult to control the temperature and the workability deteriorates. If the cooling temperature is too high, the solidification of the cooling becomes incomplete, which is not preferable. In the present invention, after the melt-spinning, the undrawn yarn may be wound once, or the process may proceed to the next step continuously without winding the undrawn yarn once. That is, either the one-step method or the two-step method may be employed.

Next, the undrawn yarn is heated to 80 to 130 ° C. At this time, the heating means is a heating roller 1
It is preferable to heat-treat by winding around the heating roller 1. This heat treatment is for preheating, and when the heating roller 1 is used, it may be wrapped three to six times. If the heat treatment temperature is lower than 80 ° C., a sufficient effect is not exhibited in the next heat stretching and heat treatment steps, and
If the temperature is higher than 30 ° C., superdraw occurs and the specific gravity of the multifilament does not decrease, but a high-strength multifilament cannot be obtained.

Next, heat treatment and thermal stretching for 0.5 seconds or more are continuously performed by winding a plurality of times between the double-sided heater 2 at 150 to 235 ° C. and the heating roller 3 at 150 to 235 ° C. That is, in the present invention, by performing the winding between the double-sided heater 2 and the heating roller 3 a plurality of times in this manner, the thermal stretching and the heat treatment are continuously performed, and further, the time for performing the thermal stretching and the heat treatment is 0.5 seconds. Above. As a result, a sufficient amount of heat can be given to the yarn, and it is possible to suppress the generation of voids around the inorganic fine particles and the generation of fluff on the surface of the filament generated at the time of drawing. An excellent filament can be obtained.

FIG. 2 is a process chart showing an embodiment of a conventional manufacturing method. In the method of stretching and heat-treating by providing a preheating roller 7 and a stretching roller 9 and a heat treatment heater 8 between them, the heat treatment is generally performed. The time is 0.04-0.08
Second, and the heat treatment is performed when passing through the heater 8, and the thermal stretching is performed after passing through the heater 8. Therefore, continuous stretching and heat treatment are not performed as in the present invention, and a sufficient amount of heat is obtained. Not granted. Therefore, the resulting fiber has voids and is inferior in both quality and physical properties.

The temperature of the double-sided heater 2 and the heating roller 3 is 15
The temperature is 0 to 235 ° C, more preferably 170 to 220 ° C. If the temperature of the double-sided heater 2 and the heating roller 3 is less than 150 ° C., a sufficient amount of heat cannot be given to the filament, and the generation of voids around the inorganic fine particles and the fluff on the filament surface during stretching can be suppressed. Can not.

The temperature of the double-sided heater 2 and the heating roller 3 is 23
If the temperature is higher than 5 ° C., the filament may be fused or broken when the filament is wound and heat-treated.

In the present invention, the number of windings between the double-sided heater 2 and the heating roller 3 may be appropriately selected depending on conditions such as a winding speed so that heat treatment and thermal stretching for 0.5 seconds or more can be performed. It is preferable that the number of times be equal to or more than 5 times, more preferably about 5 to 10 times. The thermal stretching is completed by approximately four windings, and at this time, the heat treatment is performed together with the thermal stretching. However, when the winding is performed more than that, the heat treatment is mainly performed.

If the time for performing the heat stretching and the heat treatment is less than 0.5 seconds, sufficient heat can be applied to the filament even if the temperatures of the double-sided heater 2 and the heating roller 3 satisfy the above ranges. It is not possible to suppress generation of voids around the inorganic fine particles and fluff on the filament surface during stretching. A more preferable range of the heat treatment time is 0.
When the heat treatment time exceeds 1.2 seconds, the heat treatment effect is saturated, and the operability tends to deteriorate.

Further, in the method of the present invention, the stretching tension is reduced by winding the film between the double-sided heater 2 and the heating roller 3 and performing stretching and heat treatment, thereby improving the stretching property and improving the fluff on the filament surface. It is thought that the occurrence of can be suppressed.

In the stretching of the present invention, the stretching ratio is preferably 4.5 to 6.5 times. By stretching in this range, it is possible to obtain a filament with less generation of voids and fluff.

After stretching and heat treatment, the film is taken up by the roller 4, subjected to a relaxation treatment between the heating roller 3 and the roller 4, and
Take up with. At this time, since a sufficient amount of heat is applied in the previous step, the rollers 4 subsequent to the heating roller need not be heating rollers. And the relaxation rate is preferably 5 to 12%. If the relaxation rate exceeds 12%, excessive relaxation treatment causes unevenness in the thread properties and causes deterioration in workability. On the other hand, if the relaxation rate is less than 5%, it is difficult to make the linear cut elongation 15% or more.

The filament obtained by the production method of the present invention is a core-sheath composite multifilament having a specific gravity of 1.45 or more and a strength of 4.2 g / d or more. A more preferable range of the specific gravity is 1.50 to 1 .65, and a more preferable range of the strength is 4.5 to 6.0 g / d. Further, the cutting elongation is about 15% or more.

Further, it is appropriate that the obtained filament has a single yarn fineness of 4 to 50 d and a total fineness of 100 to 2000 d.

[0031]

Next, the present invention will be described specifically with reference to examples. In addition, measurement and evaluation of various values in the examples were performed as follows. (A) Relative Viscosity of Polyester The polyester was measured at a concentration of 0.5 g / d1 at a temperature of 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent. (B) Strength and elongation Measured using an autograph DSS-500 manufactured by Shimadzu Corporation at a sample length of 25 cm and a tensile speed of 30 cm / min. (C) Specific gravity The obtained fiber piece having a length of 10 mm was
A solution in which 1-dichloro-2,2,3,3,3-pentafluoropropane and 1,3-dichloro-1,1,2,2,3-pentafluoropropane are mixed at a volume ratio of 45/55. And a chlorofluoroethylene low-polymer solution were immersed in a mixed solution having an arbitrary specific gravity, defoamed, and measured by a floatation method. (D) Operability Yarn was formed for 24 hours, and evaluated according to the following five stages based on the number of yarn breaks during stretching (stretchability). A: 0 times B: 1 time C: 2 times D: 3 times E: 4 times or more (e) Stretching tension It was measured using a tension meter (model-CB1000) manufactured by Kanai Koki. (F) Fluff Using a DSS21-21-OPW high-speed partial warping machine manufactured by Tominaga Machinery Co., Ltd., the presence or absence of fluff was investigated at a measurement length of 10,000 m and a winding speed of 500 m / min. The following fluff evaluation value is 100
The following five grades were used to evaluate the value per 10,000 m. A: 0 to 4 pieces / million m B: 5 to 9 pieces / million m C: 10 to 49 pieces / million m D: 50 to 99 pieces / million m E: 100 pieces or more / million m

Example 1 Polyethylene terephthalate (PE) having a relative viscosity of 1.41
T) 49.0% by weight of resin, 0.5 μm in average particle diameter, 2.0 μm in maximum particle diameter, 50.0% by weight of precipitated barium sulfate fine particles (BaSO4) having a specific gravity of 4.3, and 1. as a colorant (black). 0% by weight of carbon black is mixed, and the specific gravity is 2.
30 high specific gravity chips for the core layer were obtained. Note that a bisphenol S-based compound was used as a melt viscosity reducing agent. on the other hand,
A PET chip having a relative viscosity of 1.68 was prepared for the sheath layer. The above-described high specific gravity chip for the core layer and the PET chip for the sheath layer are supplied to separate melt extruders, each of which is melted at 295 ° C. and has 32 spinning holes of 0.6 mm in diameter heated to 295 ° C. From the spinneret, core / sheath composite volume ratio 30/7
0 concentric composite multifilaments were spun. The spun yarn was cooled and solidified by blowing air at 20 ° C., and then a spinning oil agent was applied and wound once. According to the process diagram of FIG.
Minute, and then heated to 215 ° C with heating roller 1.
The sheet was wound eight times around the double-sided heater 2 at 215 ° C. between the heating rollers 3 and 5.1 times of thermal stretching and heat treatment were continuously performed.
During this time, the heat stretching and heat treatment time was 1.0 second. Subsequently, the film was relaxed with a roller 4 (room temperature) at a relaxation rate of 7% and wound around a winder 5 to obtain a multifilament of 500d / 32f.

Example 2 A multifilament was obtained in the same manner as in Example 1 except that the core / sheath composite volume ratio was changed to 40/60.

Examples 3-12 The temperature of the heating roller 1 (Examples 3-4), the temperature of the double-sided heater 2 and the temperature of the heating roller 3 (Examples 5-6), the temperature of the heating roller 3 and the temperature of the double-sided heater 2 Number of turns (Examples 7 to 8),
Stretching ratio (Examples 9 to 10), relaxation rate (Examples 11 to 1)
A multifilament was obtained in the same manner as in Example 1, except that 2) was changed as shown in Tables 1 and 2.

Tables 1 and 2 show the yarn characteristics and the like of the composite multifilaments obtained in Examples 1 to 12.

[0036]

[Table 1]

[0037]

[Table 2]

Comparative Examples 1 to 4 The temperatures of the heating roller 1 (Comparative Examples 1 and 2), the temperature of the double-sided heater 2 and the temperature of the heating roller 3 (Comparative Examples 3 and 4) were changed as shown in Table 3. A multifilament was obtained in the same manner as in Example 1.

Comparative Example 5 The wound undrawn yarn was taken up by a heating roller 7 at 115 ° C. at a speed of 65 m / min according to the process diagram of FIG. The film is stretched 5.1 times while being in contact with the plate 8, relaxed at a relaxation rate of 7% between the roller 9 and the heating roller 10, and wound up by the winder 5 at 500 d.
/ 32f multifilament was obtained. The heat treatment time of this method was 0.05 seconds.

Table 3 shows the yarn properties and the like of the multifilaments obtained in Comparative Examples 1 to 5.

[0041]

[Table 3]

As apparent from Tables 1 and 2, Examples 1 to
In No. 12, since the heat drawing and the heat treatment were continuously performed while giving a sufficient amount of heat, the yarn could be manufactured with good yarn-making properties, and the obtained filament had no fluff or the like on the surface, and had excellent physical properties at a high specific gravity. Was something. On the other hand, as is clear from Table 3, in Comparative Example 1, since the temperature of the heating roller 1 was too low, the yarn was broken at the time of stretching, and the obtained filament was fuzzed. In Comparative Example 2, since the temperature of the heating roller 1 was too high, the obtained filament had low strength. In Comparative Example 4, since the temperatures of the double-sided heater 2 and the heating roller 3 were too high, the yarn was broken by fusion, and a filament could not be obtained. In Comparative Example 3, a sufficient amount of heat could not be given because the temperatures of the double-sided heater 2 and the heating roller 3 were too low. In Comparative Example 5, the conventional method was used, and the heat treatment time was short. Can not give
Since the stretching tension was also increased, the yarn was broken at the time of stretching, and the obtained filament had fluff and voids, had a low specific gravity, and was inferior in quality.

[0043]

According to the production method of the present invention, a filament having a higher specific gravity can be obtained without generating voids inside the filament, and a filament having a high strength can be obtained without generating fluff on the surface of the filament. As a result, high-speed netting can be achieved, and a fishing net having the necessary strength as a fishing net, having a high sedimentation speed in water, and having excellent shape retention against tides can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic process chart showing one embodiment of a method for producing a high specific gravity composite filament of the present invention.

FIG. 2 is a schematic process diagram showing one embodiment of a conventional method for producing a high specific gravity composite filament.

[Explanation of symbols]

 Y Undrawn multifilament 1 Heating roller 2 Double-sided heater 3 Heating roller 4 Roller 5 Winder 6 Cheese 7 Heating roller 8 Heat treatment heater 9 Roller 10 Heating roller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Suehiro 5 Ujitonouchi, Uji-city, Uji, Kyoto, Japan Unitika Plant Uji Factory (72) Inventor Ryuji Sakai 5 Ujitonouchi, Uji-shi, Kyoto, Japan 5 Unitika Co., Ltd. Reference) 4L036 MA05 MA15 PA18 4L041 AA07 AA18 AA19 AA20 AA25 BA02 BA05 BA21 BC20 BD02 BD20 CA06 CB02 CB06 CB21 CB25 CB28 CB29 DD01 DD04 DD21

Claims (2)

[Claims] 1. A polyester resin having a core part containing 20 to 80% by weight of inorganic fine particles and a sheath part made of a polyester resin having a relative viscosity of 1.5 or more, having a specific gravity of 1.45 or more and a strength of 4.2 g / d. The method for producing a core-sheath composite multifilament as described above, wherein the spinning speed is 200 to 1000 m /
After the melt-spinning in minutes, the obtained undrawn yarn is heated to 80 to 130 ° C., and a double-sided heater at 150 to 235 ° C. and 150 to 235 ° C.
A method for producing a high-specific-gravity composite filament, comprising performing heat treatment and heat stretching for 0.5 seconds or more by winding a plurality of times between heating rollers at 235 ° C., and then relaxing and winding. 2. The method according to claim 1, wherein the stretching ratio is 4.5 to 6.5 times and the relaxation rate is 5.0 to 12% when the film is wound plural times between the double-sided heater and the heating roller and thermally stretched. Item 3. The method for producing a high specific gravity composite filament according to Item 1.