JP2007056382A - Method for producing high specific gravity composite fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a high specific gravity composite fiber having high tensile strength and high specific gravity with good elongation by enhancing drawing flowability of a core component containing high specific gravity particles and suppressing generation of voids and fluffs caused by drawing to the minimum. <P>SOLUTION: The method for producing the high specific gravity composite fiber having ≥3.5 cN/dtex strength and ≥1.45 specific gravity is to melt spin a sheath component containing a polyethylene terephthalate as a main component and the core component containing high specific gravity particles using a melt spinning device for the composite fiber, continuously draw the fiber without winding the undrawn fiber, bring a second stage drawing (without containing draw arrangement) to be in 4.0-6.0 times of total rate of drawing, carry out the second stage drawing by blowing ≥300°C steam to the fiber in 1.2-1.6 times of rate of drawing, subsequently wind the fiber by relaxation treatment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a high specific gravity composite fiber that contains high specific gravity particles in a core component and has a high specific gravity (good sedimentation property) and high strength suitable for marine materials.

  Conventionally, synthetic fibers such as polyester and polyamide have high strength, and are therefore used as fibers for fishery materials such as fishing nets.

  Among the fibers for marine products, the fibers used for stationary nets must have high specific gravity to increase the sedimentation rate in water and to improve the shape of the fishing net against tidal currents. It has been. Among the synthetic fibers, polyesters are used that are inexpensive, have a relatively high specific gravity, and easily obtain high strength. Among them, polyethylene terephthalate fibers are often used.

  In recent years, fibers having a higher specific gravity have been demanded. As described in Patent Document 1 and Patent Document 2, the core component of the core-sheath composite fiber contains high specific gravity particles, and the specific gravity is 1.5. A high specific gravity composite fiber having a thickness of 1.7 or more has been proposed.

  However, in such a composite fiber, when high specific gravity particles are contained in the core component at a high concentration, uniform dispersion tends to be difficult, and as a result, the portion where the high specific gravity particles are contained at a high concentration when stretched is Due to inferior stretching fluidity, voids (voids) are generated in the core component, making it difficult to obtain a fiber having a specific gravity corresponding to the content of high specific gravity particles in the fiber, or by cutting the core component There was a problem that stretched fluff, which was thought to be generated, was present in the wound product, and the workability was inferior, such as frequent stoppage of the machine base during netting.

  In view of the current situation, in Patent Document 3, nylon is used as the thermoplastic polymer of the core component, and one-stage stretching and shrinkage at a stretching ratio of 4.3 to 4.8 times while spraying heated steam at 350 ° C. or higher during stretching. A manufacturing method for performing the processing has also been proposed.

However, in the technique of Patent Document 3, when the thermoplastic polymer of the core component is polyester, the generation of voids increases and the specific gravity rather decreases, which is not a satisfactory method.
JP-A-8-311721 JP-A-8-144125 Japanese Patent No. 3335063

  The present invention solves the above problems, improves the stretching fluidity of the core component containing high specific gravity particles, minimizes the generation of voids and stretched fluff, and has a high specific gravity (good sedimentation properties). And a method for producing a high specific gravity composite fiber having high strength with good stretchability.

  As a result of intensive studies to solve the above problems, the present inventors have reached the present invention.

  That is, the present invention provides a sheath component mainly composed of polyethylene terephthalate and a core-sheath composite fiber mainly composed of polyester containing high specific gravity particles, which is melt-spun using a melt composite spinning device, This is a method for producing a high specific gravity composite fiber having a strength of 3.5 cN / dtex or more and a specific gravity of 1.45 or more, which is continuously drawn without being wound once, and is drawn in two stages using a heating roller. Alignment is not included) so that the total draw ratio is 4.0 to 6.0 times, and the second stretch is performed by blowing steam at a temperature of 300 ° C. or higher onto the fibers while the draw ratio is 1.2 to 1. The gist of the present invention is a method for producing a high specific gravity composite fiber, characterized in that the fiber is wound while being stretched 6 times and then subjected to a relaxation treatment.

  According to the method for producing a high specific gravity composite fiber of the present invention, when producing a high specific gravity composite fiber containing high specific gravity particles in the core component by a spin draw method, the drawing is a two-stage drawing, and the second stage drawing. By spraying steam at a temperature of 300 ° C. or higher onto the fiber, it becomes possible to produce a fiber having high specific gravity and good sedimentation and high strength with good stretchability.

  Hereinafter, the present invention will be described in detail.

  The method for producing a high specific gravity composite fiber according to the present invention is a spin draw in which a core-sheath type composite fiber containing high specific gravity particles as a core component is continuously drawn without being wound in an undrawn fiber state. It is a method of manufacturing by the method.

  First, the sheath component of the composite fiber obtained by the present invention is mainly composed of polyethylene terephthalate (hereinafter referred to as PET) which is inexpensive, has a relatively high specific gravity, and is excellent in dimensional stability in consideration of strength and yarn-making property. Is preferred.

  The intrinsic viscosity [η] of PET is preferably 0.9 to 1.2. If the intrinsic viscosity is lower than 0.9, it may be difficult to obtain a fiber having high strength. On the other hand, if the intrinsic viscosity is higher than 1.2, stretchability may be deteriorated.

  Next, the polyester used for the core component includes aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene 2,6 dicarboxylic acid, phthalic acid, α, β- (4-carboxyphenoxy) ethane, and 5-sodium sulfoisophthalic acid. Aliphatic dicarboxylic acids such as acids, adipic acid and sebacic acid or derivatives thereof, ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4-dimethanol , Polyesters polycondensed from diol compounds such as polyethylene glycol and tetramethylene glycol, and copolymers and mixtures thereof. Among these, PET, polybutylene terephthalate, which are excellent in dispersibility and stretchability of high specific gravity particles, and copolymerized PET and copolymerized polybutylene terephthalate containing these main components are preferable.

  The intrinsic viscosity [η] of the core component is preferably 0.6 to 0.9 before kneading the high specific gravity particles. When the intrinsic viscosity is lower than 0.6, the core component may be cut during stretching, resulting in poor stretchability. On the other hand, when the intrinsic viscosity is higher than 0.9, stretch fluidity may be degraded.

  In the present invention, metal particles such as barium, titanium, aluminum and tungsten, and metal compounds such as titanium dioxide, zinc oxide and precipitated barium sulfate can be used as the high specific gravity particles to be contained in the core component. Of these, barium sulfate is preferable because of its high specific gravity, excellent dispersibility of the core component in polyester, and excellent stretchability.

  In addition, the maximum particle diameter (diameter) of the high specific gravity particles is preferably 4.0 μm or less, and more preferably 3.0 μm or less in consideration of stretchability.

  The content of the high specific gravity particles to be contained in the core component is preferably 30 to 70% by mass in the core component. When the content of the high specific gravity particles is less than 30% by mass in the core component, it is necessary to increase the composite ratio of the core component in order to increase the fiber specific gravity, and the composite ratio of the sheath component decreases, thereby reducing the strength. It may be difficult to obtain a high fiber. On the other hand, when it exceeds 70 mass% in a core component, it will become difficult to knead into a core component uniformly, and it may become inferior to extending | stretching fluidity | liquidity.

  Moreover, as a method used at the time of spinning, it is preferable to use, as a core component, a material obtained by kneading arbitrary high specific gravity particles uniformly into a polyester used as a core component in advance.

  Next, the core-sheath composite ratio of the composite fiber is preferably 30:70 to 70:30 in terms of mass ratio (core: sheath). If the ratio of the core component is smaller than this range, it may be difficult to increase the specific gravity. On the other hand, when the ratio of the core component is larger than this range, the ratio of the sheath component decreases and the strength of the fiber tends to decrease.

  In addition, as long as the core component and the sheath component do not impair the effects and properties, matting agents such as titanium oxide, antioxidants such as hindered phenol compounds, ultraviolet absorbers, light stabilizers, pigments, flame retardants, An antibacterial agent, a conductivity imparting agent or the like may be blended.

  The cross-sectional shape of the conjugate fiber in the present invention may be an irregular shape such as a polygonal shape or a multileaf shape for both the core component and the sheath component. Further, an eccentric core-sheath type in which the center points of the core component and the sheath component do not coincide with each other may be used. Among them, a concentric core-sheath conjugate fiber having a round cross-sectional shape in which the center points of the core component and the sheath component coincide with each other because a high strength is easily obtained is particularly preferable.

  The method for producing a high specific gravity composite fiber of the present invention is based on a spin draw method, in which a heating roller is used to perform two-stage stretching (not including alignment), followed by winding while performing a relaxation treatment. is there.

  At that time, the total draw ratio of the first and second stages needs to be 4.0 to 6.0 times, and preferably 4.5 to 5.7 times. If the total draw ratio is less than 4.0 times, high strength is difficult to obtain, and if it exceeds 6.0 times, the draw fluidity of the core component containing high specific gravity particles is inferior. Stretch fluff is likely to occur.

  When the high specific gravity conjugate fiber is stretched in two stages, the stretch ratio in the second stage is preferably 1.2 to 1.6 times in terms of increasing strength and stretchability, and more preferably 1.3 to 1. .5 times. If the stretching ratio of the second stage is out of this range, it is not preferable because it becomes difficult to increase the strength or the stretchability becomes inferior.

  Further, the second-stage drawing needs to be performed while spraying steam on the fibers in order to improve drawability. The reason for this is that the core component contains high specific gravity particles at a high concentration, and in the second stage of stretching, where the elongation is further reduced, the drawn fluff is considered to be caused by the cutting of the core component having poor stretching fluidity. This is to prevent the occurrence of these and voids.

The temperature of the steam sprayed on the fibers is 300 ° C. or higher, preferably 350 to 500 ° C. When the steam temperature is lower than 300 ° C., the effect of improving the stretchability is small, and the stretchability becomes poor. If the temperature is too high, fusion between filaments and yarn breakage may occur. Therefore, the upper limit of the steam temperature is about 500 ° C. The pressure of the steam used in the second drawing is 0.3 to 0.00. 8 Mpa is preferable, and if the steam pressure is lower than 0.3 Mpa, the effect of improving stretchability tends to be lowered, and if it exceeds 0.8 Mpa, yarn breakage tends to occur.

  In the present invention, when steam is sprayed on the fiber during the first stage of stretching, the stretching tension is low, so the stretching concentrates on the steam spraying part, and the finer sharply progresses, resulting in more voids in the core component. This is not preferable because it is difficult to obtain fibers with high specific gravity.

  Next, the method of spraying steam on the fiber is not limited at all, and the angle of 30 to 80 degrees from the orifice or slit-shaped steam blowing hole arranged on one side or symmetrically toward the traveling direction of the fiber. It is preferable to spray the fibers.

  The composite fiber obtained in the present invention has a specific gravity of 1.45 or more, particularly preferably 1.50 or more. When the specific gravity of the composite fiber is less than 1.45, the settling property and shape retention of the fishing net are insufficient when used for stationary net use. Further, since the high specific gravity particles are contained in the core component, it is necessary to increase the content of the high specific gravity particles in order to increase the specific gravity. However, it becomes difficult to increase the strength of the fiber as the content of the high specific gravity particles increases. Accordingly, when the high specific gravity particles are 70% by mass or less in the core component as described above, the upper limit of the fiber specific gravity is preferably 1.80 in order to obtain a fiber having a strength of 3.5 cN / dtex or more.

  The strength of the composite fiber obtained by the present invention is 3.5 cN / dtex or more, and particularly preferably 4.0 cN / dtex or more. When the strength of the composite fiber is less than 3.5 cN / dtex, the strength is insufficient for use in marine products. Then, considering the fiber specific gravity as described above, the upper limit of the strength is preferably 5.0 cN / dtex.

  Furthermore, in consideration of wear resistance and yarn production, it is preferable that the single yarn fineness of the composite fiber obtained in the present invention is 10 to 30 dtex and the elongation is 15 to 20%.

  Next, one embodiment of the method for producing a high specific gravity conjugate fiber of the present invention will be further described.

  A core-sheath composite spinneret is attached to a composite melt spinning apparatus, and a core component and a sheath component are introduced to perform melt spinning. After passing the spun fiber through a heating cylinder with a wall surface temperature of 200-500 ° C. installed directly under the die, cooling air is blown with a cooling air at a temperature of 10-30 ° C. and a speed of 0.5-1 m / sec. Cool and apply oil.

  Thereafter, the sheet is taken up by a non-heated first roller, and subsequently applied to a second roller having a surface temperature of 120 to 170 ° C., and is aligned 1.005 to 1.05 times, and a third roller having a surface temperature of 130 to 200 ° C. The first stage of stretching is performed between Subsequently, a steam processing machine is installed between the fourth roller and the third roller having a surface temperature of 200 to 260 ° C., and the total draw ratio is 4.0 to 6.0 times while spraying steam of 300 ° C. or higher. Thus, the second stage stretching is performed at a stretching ratio of 1.2 to 1.6 times. Thereafter, a relaxation heat treatment of 2 to 5% is performed between the fifth roller having a surface temperature of 100 to 200 ° C., wound on a winder at a speed of 1500 to 3500 m / min, the strength is 3.5 cN / dtex or more, and the specific gravity is A high specific gravity composite fiber of 1.45 or more is obtained.

Next, the present invention will be specifically described with reference to examples. In addition, evaluation of each physical property in this invention was performed with the following method.
(A) Intrinsic viscosity Measured at a concentration of 0.5 g / dl and a temperature of 20 ° C. using an equal mass mixture of phenol and ethane tetrachloride as a solvent.
(B) Strength and elongation JIS L-1013 According to a standard test of tensile strength and elongation, Shimadzu Autograph DSS-500 was used and the sample length was 25 cm and the tensile speed was 30 cm / min.
(C) Specific gravity of fiber It measured according to JIS L-1013 specific gravity (floating and sinking method).
(D) Stretchability
Each 5.0 kg roll of 10 cheeses was collected, and each stretched fluff on the cheese surface was visually determined and evaluated in the following three stages.
○: No stretched fluff is generated.
Δ: Stretched fluff was generated in 1-2 cheese.
X: Stretched fluff was generated over 3 cheeses.

Example 1
PET having an intrinsic viscosity of 1.1 is used as a sheath component, and precipitated barium sulfate having an average particle size of 0.6 μm, a maximum particle size of 2.0 μm, and a specific gravity of 4.3 is added to PET having an intrinsic viscosity of 0.8 as a core component. What melt-mixed so that it might become 55 mass% in a core component (chip) was used.
Then, the core component and the sheath component are introduced into a composite melt spinning apparatus, and the temperature is 290 ° C., the core-sheath mass ratio (core: core: core core-type composite spinneret having a diameter of 0.6 mm and a number of holes of 60 holes. Sheath) Melt spinning at 35:65.
The spun fiber was passed through a heating cylinder having a wall surface temperature of 350 ° C., and then cooled by blowing cooling air at a temperature of 15 ° C. and a speed of 0.8 m / second using a horizontal cooling device to give an oil agent. Subsequently, the film is taken up by a non-heated first roller, aligned 1.01 times with a second roller having a surface temperature of 150 ° C., and then transferred with a third roller having a surface temperature of 160 ° C. Drawing was performed twice (first stage). Then, using a steam processing machine, while spraying steam with a surface temperature of 400 ° C. and a pressure of 0.4 Mpa on the fibers, stretching is performed 1.3 times (second stage) with a fourth roller having a surface temperature of 240 ° C. 3% relaxation heat treatment with a surface 5th roller at a temperature of 150 ° C. and a speed of 2015 m / min, wound around a winder of a speed of 2000 m / min, and concentric core-sheath composite fiber with 1110 dtex / 60 filament Got.

Example 2
It carried out similarly to Example 1 except having changed the core-sheath mass ratio into 40:60.

Comparative Examples 1-4
The same procedure as in Example 1 was performed except that the stretching conditions were variously changed as described in Table 1.

  As is clear from Table 1, in Examples 1 and 2, composite fibers having high strength and high specific gravity were obtained, and these fibers also had good stretchability.

On the other hand, Comparative Example 1 was inferior in stretchability because steam was not used in the stretching process, and Comparative Examples 2 and 3 were made of rapid stretching because of the use of steam in the first stage stretching. The specific gravity was slightly low and the stretchability was inferior. Further, Comparative Example 4 had no effect of improving stretchability because the steam temperature was low.

Claims (1)

A sheath component mainly composed of polyethylene terephthalate and a core-sheath composite fiber mainly composed of polyester containing high specific gravity particles are melt-spun using a melt compound spinning device, and the unstretched fiber is continuously wound without being wound up. A high specific gravity composite fiber having a strength of 3.5 cN / dtex or more and a specific gravity of 1.45 or more, and is a two-stage drawing (not including drawing) using a heating roller. The total stretching ratio is 4.0 to 6.0 times, and the second stage stretching is performed at a stretching ratio of 1.2 to 1.6 times while spraying steam at a temperature of 300 ° C. or higher onto the fibers. A method for producing a high specific gravity composite fiber, characterized in that the fiber is wound while performing a relaxation treatment.