JPH08144126A - Polyester fiber for fishery material and its production and fishnet - Google Patents

Abstract

PURPOSE: To obtain the subject fiber for fishnets etc., consisting of high-specific gravity sheath-core type conjugate fiber excellent in resistance to hydrolysis and aminolysis. CONSTITUTION: This polyester fiber for fishery materials is a sheath-core type conjugate fiber which is obtained by the following process: as core layer, a mixture >=1.8 in specific gravity comprising a polyester and high-specific gravity fine powder consisting of metal and/or metal compound 5-22 in specific gravity, <=11m<2> /g in specific surface area, <=1μm in average particle diameter and <=2μm in maximum particle diameter and, as sheath layer, a mixture comprising polyethylene terephthalate <=20eq/t in terminal carboxyl group level or a polyester predominant therein and 0.3-2wt.% of a monocarbodiimide compound, are subjected to melt spinning and the resultant yarn is drawn and heat-treated. This polyester fiber has the following characteristics: the terminal carboxyl group level in the sheath layer: <=5kg/t; tensile strength: >=45kg/mm<2> : tensile elongation at break: >=45%; knot strength: >=30kg/mm<2> ; and specific gravity: >=1.7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber for marine materials, which comprises a high specific gravity core-sheath composite fiber having excellent hydrolysis resistance and amine decomposition resistance, a method for producing the same, and a fishing net.

[0002]

2. Description of the Related Art Polyester fibers have various excellent properties and are also used as fibers for marine products such as fishing nets (for example, see Japanese Examined Patent Publication No. 58-38530). , Dry it on the beach, decompose and decompose the seafood attached to the fishing net, wash and dry it, and use it again. Then, when corroding and decomposing seafood, put a sheet on the dried fishing net to make the inside of the sheet hot and humid,
The decomposition of fish and shellfish is promoted to shorten and simplify the fishing net washing process. At that time, when polyester fiber is used as the constituent thread of the net, the fishing net undergoes amine decomposition and hydrolysis to deteriorate due to the synergistic effect of ammonia, water and heat generated as decomposition components of seafood, and the net strength is increased. There was a problem that it decreased and it became impossible to use for a long time.

[0003] Polyester fiber is a synthetic fiber having a relatively large specific gravity, but a higher specific gravity is desired in order to improve the shape retention of the fishing net against tidal current because the sedimentation speed in water is high. ing.

Conventionally, various methods have been proposed for obtaining a synthetic fiber having a high specific gravity by incorporating a powder having a high specific gravity. However, the strength of the obtained fiber is lowered, and the fiber has a high specific gravity and is required as a fishing net. It has been difficult to obtain high strength fibers.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a polyester fiber for marine products having excellent hydrolysis resistance and amine decomposition resistance, high specific gravity and high strength, a method for producing the same, and a fishing net using the fiber. Is to provide.

[0006]

The present invention is intended to solve the above-mentioned problems, and its gist is as follows. (1) As the core layer, polyester has a specific gravity of 5 to 22, a specific surface area
11m ² / g or less, average particle size 1μm or less, maximum particle size 2μm or less Mixture of high specific gravity fine powder consisting of metal and / or metal compound with specific gravity of 1.8 or more, as sheath layer, carboxyl end group amount 20eq / t A core-sheath composite fiber obtained by melt-spinning, stretching and heat treatment using a mixture of the following polyethylene terephthalate or a polyester mainly containing the same and a monocarbodiimide compound added thereto in an amount of 0.3 to 2% by weight. Carboxyl end group amount less than 5eq / t, linear strength
45kg / mm ² or more, linear cutting elongation 15% or more, knot strength 30kg / m
Polyester fiber for marine products, having a specific gravity of 1.7 or more and m ² or more.

(2) The method for producing a polyester fiber for marine products according to item (1), characterized in that the following steps are carried out in sequence.
(a) Polyester with a specific gravity of 5 to 22, a specific surface area of 11 m ² / g or less,
Metals with an average particle size of 1 μm or less and a maximum particle size of 2 μm or less and /
Alternatively, a step of uniformly dispersing fine powder of high specific gravity composed of a metal compound to obtain a core layer material having a specific gravity of 1.8 or more, (b) Polyethylene terephthalate having a carboxyl end group content of 20 eq / t or less, or a polyester mainly composed of this monocarbodiimide The compound was added in an amount of 0.3 to 2% by weight to form a sheath layer material and subjected to composite melt spinning together with the above core layer material, and the sheath layer had a carboxyl end group content of 5 eq / t or less and a fiber specific gravity of 1.7 or more. (C) Core-sheath composite unstretched fiber is stretched and heat-treated to obtain a linear strength of 45 kg / mm ² or more, a linear cutting elongation of 15% or more, a knot strength of 30 kg / mm ² or more, and a specific gravity of 1.7 or more. The step of obtaining the composite fiber.

(3) A fishing net braided using the polyester fiber for marine products according to item (1).

In the present invention, the amount of carboxyl end groups of the polyester is determined by dissolving the polyester in benzyl alcohol and titrating with 0.1N potassium hydroxide methanol solution. (The amount of carboxyl end groups in the sheath layer of the composite fiber is determined by eluting the polyester in the sheath layer with an equal weight mixed solvent of phenol and ethane tetrachloride, and removing the solvent by using the polyester as a sample by the above method. The strength and elongation are measured according to JIS L 1013 method.

Hereinafter, the present invention will be described in detail.

As described above, fibers for marine products are required to have high strength as well as high specific gravity. The sheath layer is a portion responsible for the strength of the fiber, and in the present invention, as the sheath layer,
Polyethylene terephthalate, which expresses high strength by stretching, or mainly composed of it, isophthalic acid, adipic acid, sebacic acid, 2,6-naphthalenedicarboxylic acid, 1,4
A polyester containing a small amount of cyclohexanedicarboxylic acid, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol as a copolymerization component is used.

Further, as described above, since the fibers for marine products are also required to have abrasion resistance, it is necessary to prevent peeling at the interface between the sheath layer and the core layer. Also, a polyester having compatibility with the sheath layer is used. Usually, the same polyester as that used for the sheath layer is used for the core layer.

The polyester used in the present invention preferably has a relative viscosity (measured at a concentration of 0.5 g / dl and a temperature of 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent) in the range of 1.40 to 1.75. When the relative viscosity of the polyester of the core layer is less than 1.40, a decrease in melt viscosity of the mixture occurs by compounding the high specific gravity fine powder, and further,
When melted again during spinning, the viscosity is markedly reduced, making it difficult to obtain stable spinning properties. Further, if the relative viscosity of the sheath layer is less than 1.40, high-strength fibers cannot be obtained, and the abrasion resistance also decreases. On the other hand, when the relative viscosity of the polyester exceeds 1.75, there is a problem that the unevenness of the melt may occur or the fluidity of the melted polymer may be bad and the surface of the fiber may be roughened during the fiber formation process. When the value is high, there is a problem that thermal decomposition of the polymer occurs and the effect of the high viscosity polymer is lost.

The carboxyl terminal group plays a catalytic role in the hydrolysis of the polyester, and the hydrolysis proceeds by the attack of water molecules on the ester bond. Further, in the amine decomposition, an amide end group and a water molecule are generated by a neutralization reaction between ammonia and a carboxyl end group in the initial stage of the reaction,
Subsequently, hydrolysis is caused by water molecules and ester bonds to proceed. That is, the degradation of polyester is greatly affected by the amount of terminal carboxyl groups.

Since a polymer having a smaller amount of carboxyl end groups has a slower hydrolysis rate, it is necessary to set the amount of carboxyl end groups of the polyester for the sheath layer to 20 eq / t or less, preferably 5 to 19 eq / t. Further, by satisfying this condition, the terminal blocking agent can finally reduce the amount of carboxyl terminal groups in the sheath layer of the filament to 5 eq / t or less. This is because when the amount of carboxyl end groups of the raw material polymer is 20 eq / t or more, the filament after spinning and drawing does not exhibit resistance to hydrolysis and amine decomposition, and further, the carboxyl end of the sheath layer of the filament after spinning and drawing. It is necessary to add a large amount of the end-capping agent in order to reduce the amount of the base to 5 eq / t or less, which is a disadvantage from an industrial viewpoint.

Such a polyester for the sheath layer can be obtained as follows. That is, first, a prepolymer having a relative viscosity of 1.30 to 1.44 is obtained by an ordinary melt polymerization method. Next, the pellets of this prepolymer are heated under reduced pressure or under the flow of an inert gas to carry out a solid phase polymerization reaction to obtain a polyester having a predetermined relative viscosity and a carboxyl terminal group amount. If the relative viscosity of the prepolymer is not suitable,
Since the total polymerization time becomes extremely long, or the amount of carboxyl end groups of the polyester after solid phase polymerization cannot be set within a predetermined range, the relative viscosity of the prepolymer can be set within the above range. desirable.

The solid-phase polymerization conditions are preferably selected so that the relative viscosity becomes about 0.10 to 0.40 higher than that of the prepolymer by the solid-state polymerization. This solid-state polymerization reduces the amount of carboxyl end groups of the polyester,
Impurities such as oligomers are removed.

To the polyester for the sheath layer as described above, 0.3 to 2% by weight of a monocarbodiimide compound as an end-capping agent is added and melt-spun, so that the carboxyl terminal group amount of the sheath layer of the composite fiber is 5 eq / t or less. It is necessary to do so. If the amount of carboxyl end groups of the sheath layer is more than 5 eq / t,
The long-term moist heat treatment causes remarkable deterioration of yarn quality, and the target moist heat resistance performance is not expressed.

As the monocarbodiimide compound, those represented by the following general formula are preferably used. R ¹ —N═C═N—R ^{2 In the} formula, R ¹ and R ² are phenyl groups in which at least one of the ² , 4 and 6 positions is substituted with a lower alkyl group.

Specific examples of such monocarbodiimide compounds include N, N'-bis (2,6-dimethylphenyl) carbodiimide, N, N'-bis (2,6-diethylphenyl) carbodiimide and N, N. Examples thereof include'-bis (2,6-diisopropylphenyl) carbodiimide and N, N'-bis (2-isopropylphenyl) carbodiimide.

The addition amount of the monocarbodiimide compound is
It is necessary to set it to 0.3 to 2% by weight, and unless this condition is satisfied, the target performance will not be expressed. That is, if the addition amount is less than 0.3% by weight, the blocking of the carboxyl end groups becomes insufficient, and the wet heat resistance performance is not satisfied, and if it exceeds 2% by weight, the spinnability deteriorates. The amount of the monocarbodiimide compound added is preferably such that the amount of carboxyl terminal groups in the sheath layer of the filament obtained by melt spinning becomes 5 eq / t or less and a small amount of unreacted monocarbodiimide compound remains.

The addition of the monocarbodiimide compound to the core layer can further improve the decomposition and deterioration resistance of the fiber. When the monocarbodiimide compound is added to the core layer as well, the addition amount may be 0.3 to 2% by weight like the sheath layer, but the target performance is expressed with a smaller addition amount compared to the addition amount to the sheath layer. It is possible to this is,
This is because decomposition by water, heat or amine occurs preferentially from the sheath layer.

Next, the high specific gravity fine powder added to the core layer needs to have a specific gravity of 5 to 22. In order to increase the specific gravity of the entire fiber by using a substance with a specific gravity of 5 or less,
It is necessary to add a large amount, and it becomes difficult to increase the strength of the obtained fiber. In addition, there are few substances with a specific gravity of 22 or more, and it is difficult to use from the economical aspect.

Further, high specific gravity fine powder added to the core layer has a specific surface area of 11m ² / g or less, it is necessary that those of preferably 1 to 10 m ² / g. If the specific surface area is larger than 11 m ² / g, the area covered with the polymer becomes large, resulting in a decrease in the fluidity of the core layer material and a deterioration in the spinnability. However, if the specific surface area is too small, the particle size becomes large and the fluidity of the core layer material decreases, so a specific surface area of 1 m ² / g or more is preferred.

Further, the high specific gravity fine powder has an average particle size of 1 μm.
It is necessary that the particle size is m or less and the maximum particle size is 2 μm or less. If the particle size is large, it is difficult to uniformly disperse the resin in the resin, and the spinnability is deteriorated, so that high-strength fiber cannot be obtained.

The high-specific-gravity fine powder is preferably spherical particles.

Specific examples of the high specific gravity fine powder include iron, lead, and
Fine powders of various metals such as copper, silver, nickel, zinc, tin, tungsten, gold, platinum, and stainless steel, fine powders of metal compounds such as lead oxide, barium oxide, zirconium oxide, and tungsten carbide are listed. You may use 2 or more types together.

It is necessary to properly select the type and the addition amount of the high specific gravity fine powder so that the specific gravity of the core layer material is 1.8 or more. When the specific gravity of the core layer material is less than 1.8, the ratio of the core layer to the sheath layer must be increased in order to increase the specific gravity of the whole fiber, and the ratio of the sheath layer responsible for the strength of the fiber decreases. However, it becomes difficult to increase the strength of the fiber.

The ratio of the core layer to the sheath layer is 20/80 by weight.
Appropriately 80/20, preferably 40/60 to 60/40. If the proportion of the core layer is too small, the specific gravity of the core layer material must be extremely increased, the fluidity of the core layer material deteriorates, and it becomes difficult to obtain high-strength fibers. On the other hand, if the proportion of the core layer is too large, the proportion of the sheath layer that bears the strength becomes small, and it becomes impossible to obtain high strength fibers.

The core layer material and the sheath layer material are appropriately combined, and the yarn is spun under the condition that high-strength fiber is obtained.
kg / mm ² or more, linear cutting elongation 15% or more, knot strength 30 kg / mm ²
Therefore, it is necessary to use fibers with a specific gravity of 1.7 or more. By maintaining such characteristics, it is possible to realize high-speed net-making, have the necessary strength as a fishing net, have a fast settling speed in water, and have an excellent shape retention property against tidal current. Become a fiber.

The core layer and the sheath layer may contain various additives, such as pigments, as long as their properties are not impaired.
Stabilizers and the like can be included.

Next, the method for producing the fiber of the present invention will be described.

First, fine powder having a high specific gravity is uniformly dispersed in polyester to obtain a core layer material having a specific gravity of 1.8 or more. As a method of adding the high specific gravity fine powder to the polyester, there is a method of adding it to the raw material chips during melt spinning or a method of adding it to the molten polymer during melt spinning, but the polyester and the high specific gravity fine powder are previously mixed and melt-kneaded. If it is made into chips, the workability is good and the high specific gravity fine powder can be uniformly dispersed in the polyester.

On the other hand, a monocarbodiimide compound is added to the polyester for the sheath layer to prepare a sheath layer material. However, since the monocarbodiimide compound undergoes thermal denaturation when placed in a heated state, the thermal denaturation is reduced as much as possible, In order to bring out the original properties of the carbodiimide compound, the monocarbodiimide compound is added to the polyester for the sheath layer to form the sheath layer material, and the composite melt spinning is performed together with the core layer material. In this case, the polyester chips for the sheath layer and the monocarbodiimide compound may be mixed and supplied to the extruder, but the monocarbodiimide compound may be added to the molten polyester in the middle of the extruder.

The composite fibers can be produced by a conventional method such as composite melt spinning, stretching and heat treatment.

For example, first, the core layer material and the sheath layer material are introduced as melts at a temperature of 230 to 350 ° C., preferably 250 to 310 ° C. into a spinneret pack to spin a concentric composite yarn. If the spinning temperature is too low, it is difficult to completely melt it, and if it is too high, thermal decomposition of the polymer and thermal modification of the monocarbodiimide compound occur, which is not preferable.
The spun yarn is cooled by liquid bath or gas blowing at 0-100 ° C, preferably 10-90 ° C. If the cooling temperature is too low, it is difficult to control the temperature and the workability is deteriorated. If it is too high, the cooling and solidification is incomplete, which is not preferable.

The yarn which has been solidified by cooling is stretched after or once it has been wound up. Stretching can be performed in a single stage or in multiple stages of two or more stages, but a two-stage stretching method is usually employed. That is, the stretching point does not move 65
Using a liquid bath at a temperature of up to 95 ° C, an oven at 100 to 200 ° C, or a heating roller at 70 to 110 ° C, a first stage drawing is performed at a magnification of 3 to 6 times, and then a temperature higher than the first stage is 130 to 130 ° C. 27
It is preferable to use a liquid bath at 0 ° C., an oven, or a heating roller to perform second stage stretching so that the total stretching ratio is 5 to 7 times. At this time, the total draw ratio is set to be higher than the first-stage draw ratio. If the drawing temperature is too low, the heating of the fiber will be insufficient, which will cause movement of the drawing point, yarn breakage, and yarn unevenness.If the drawing temperature is too high, superdraw phenomenon and fiber melting will occur, and the molecules will be oriented for drawing. Becomes difficult. Further, if the total draw ratio is less than 5 times, the yarn quality of the obtained fiber, particularly the linear strength, becomes low, and if it exceeds 7 times, voids are generated in the fiber and satisfactory yarn quality performance is not only exhibited. There is also no knot strength.

The liquid bath is usually used in the case of monofilament, and in the case of multifilament, it is cooled and stretched in a gas.

The drawn yarns were heated in an oven at 250 to 500 ° C. or a heating roller at 150 to 250 ° C. to have a relaxation rate of 3 to
Relaxation heat treatment of 15% is applied. If the temperature of the relaxation heat treatment is too low, the heat treatment effect on the fiber will be insufficient, and if the temperature of the relaxation heat treatment is too high, the thermal decomposition and deterioration of the polymer will occur on the fiber surface, and a fiber satisfying the target yarn quality performance can be obtained. Absent. Further, if the relaxation rate is less than 3%, the fiber has a high heat shrinkage rate and becomes unsuitable for practical use, and if it exceeds 15%, yarn sagging occurs in the relaxation heat treatment stage, resulting in poor operability and the target yarn. It does not show quality performance.

In the case of monofilament, the fineness of the yarn is
In the case of 50 to 1500 denier and multifilament, it is suitable to set the single yarn fineness to 8 to 50 denier and the total fineness to 200 to 2000 denier.

A fishing net can be obtained by net-making the core-sheath composite fibers as described above by a conventional method. The structure of the fishing net may be a generally known structure, and the fishing net of the present invention can be suitably used as a stationary net or a net.

[0042]

In the present invention, a high specific gravity polyester composition containing high specific gravity fine powder is used as the core layer material, and a low carboxyl group polyester end-capped with a monocarbodiimide compound is used as the sheath layer material.
A polyester fiber for marine products having excellent hydrolysis resistance and amine decomposition resistance, high specific gravity, high strength, and excellent dimensional stability can be obtained.

Further, an end-capping reaction is carried out by adding an excess amount of a carbodiimide compound which is an end-capping agent to the amount of carboxyl end groups of the polyester, and at the same time unreacted carbodiimide compound is left in the fiber to form in the decomposition process. By optionally blocking the carboxyl terminal group, resistance to decomposition and deterioration is developed. A fishing net using such a high specific gravity and high strength composite fiber is excellent in settling property and shape retention property in water and, at the same time, resistant to hydrolysis and amine decomposition, and thus excellent in durability.

[0044]

EXAMPLES The present invention will be specifically described below with reference to examples. The hydrolysis resistance was evaluated by the tenacity retention after treatment in saturated steam at 120 ° C for 10 days, and the amine decomposition resistance was evaluated by the tenacity retention after treatment at 135 ° C for 5 hours in ammonia gas.

Example 1 35% by weight of polyethylene terephthalate having a relative viscosity of 1.560 and a carboxyl end group amount of 17.5 eq / t and an average particle size of 0.63 μm,
65% by weight of tungsten fine powder having a maximum particle size of 1.30 μm, a specific surface area of 2.9 / mm ² and a specific gravity of 19.3 was melt-kneaded and formed into chips to obtain chips for core layer material having a specific gravity of 3.4. This core layer material chip is supplied to an extruder and melted at 270 ° C, while the relative viscosity is 1.560 and the carboxyl end group amount is 17.5.
eq / t polyethylene terephthalate chip with bis (2,6
-Diisopropylphenyl) carbodiimide was added in an amount of 1.0% by weight and supplied to another extruder, and melted at 295 ° C to form a sheath layer material, which was then composite-spun with the core layer material. At this time, the molten polymer was filtered, rectified and formed into a core-sheath structure composite flow in a spinneret pack at a temperature of 295 ° C and discharged from a spinning hole with a diameter of 1.3 mm to give a core-sheath composite weight ratio of 40%.
A / 60 concentric composite monofilament was used. After cooling the spun yarn in a 65 ° C water bath, it is passed through a heating medium bath at 100 ° C to draw 4.9 times, and then passed through an oven heater at 130 ° C to draw 1.16 times (total draw ratio). 5.7 times)
Furthermore, it was passed through an oven heater at 220 ° C and the relaxation rate
A relaxation heat treatment of 12% was performed to obtain a core-sheath composite monofilament. The yarn characteristics of the obtained monofilament are shown in Table 1.

Example 2 Using the same core layer material and sheath layer material as in Example 1, the diameter was
It was discharged from a spinneret having 20 0.6 mm spinning holes to obtain a concentric circular composite multifilament having a core-sheath composite weight ratio of 40/60. After blowing 20 ° C air on the spun yarn to cool it,
Draw 5.00 times using 90 ° C heated roller, then 2
Stretched to 1.27 times using a 40 ° C heating roller (total stretching ratio 6.
35 times) and further subjected to relaxation heat treatment at a relaxation rate of 6% using a heating roller at 170 ° C. to obtain a core-sheath composite multifilament. The yarn characteristics of the obtained multifilament are shown in Table 1.

Example 3 A core-sheath composite monofilament was obtained in the same manner as in Example 1 except that polyethylene terephthalate having a relative viscosity of 1.565 and a carboxyl terminal group amount of 14.4 eq / t was used as the polyester for the sheath layer. The yarn characteristics of the obtained monofilament are shown in Table 1.

Example 4 A core-sheath composite monofilament was obtained in the same manner as in Example 1 except that polyethylene terephthalate having a relative viscosity of 1.451 and a carboxyl terminal group amount of 19.6 eq / t was used as the polyester for the core layer. The yarn characteristics of the obtained monofilament are shown in Table 1.

Example 5 A core-sheath composite monofilament was obtained in the same manner as in Example 1 except that the composite weight ratio of the core-sheath was 50/50. The yarn characteristics of the obtained monofilament are shown in Table 1.

Examples 6 to 8 Core-sheath composite monofilaments were obtained in the same manner as in Example 1 except that the amount of the monocarbodiimide compound shown in Table 1 was added to the core-sheath material when it was melted in the extruder.
The yarn characteristics of the obtained monofilament are shown in Table 1.

Example 9 A core layer material having a specific gravity of 2.6 was obtained instead of the core layer material in Example 1 with a proportion of tungsten fine powder of 50% by weight, and the core-sheath composite weight ratio was 50/50. A core-sheath composite monofilament was obtained in the same manner as in Example 1. The yarn characteristics of the obtained monofilament are shown in Table 1.

Example 10 A core layer material having a specific gravity of 4.5 was obtained instead of the core layer material in Example 1 with a proportion of fine tungsten powder of 75% by weight, and the core-sheath composite weight ratio was 30/70. A core-sheath composite monofilament was obtained in the same manner as in Example 1. The yarn characteristics of the obtained monofilament are shown in Table 1.

[0053]

[Table 1]

Comparative Examples 1 to 3 Table 2 shows the addition amount of the monocarbodiimide compound to the sheath layer material.
A core-sheath composite monofilament was obtained in the same manner as in Example 1 except that the above was changed. The yarn characteristics of the obtained monofilament are shown in Table 2. In Comparative Example 3, the spinnability was poor.

Comparative Example 4 A core-sheath composite monofilament was obtained in the same manner as in Example 1 except that polyethylene terephthalate having a relative viscosity of 1.424 and a carboxyl terminal group amount of 27.3 eq / t was used as the polyester for the sheath layer. The yarn characteristics of the obtained monofilament are shown in Table 2.

Comparative Example 5 A core-sheath was prepared in the same manner as in Example 1 except that the core layer material in Example 1 was replaced with a core layer material having a specific gravity of 1.8, which was obtained with a proportion of fine tungsten powder of 25% by weight. A composite monofilament was obtained. The yarn characteristics of the obtained monofilament are shown in Table 2.

[0057]

[Table 2]

Comparative Example 6 A high specific gravity powder having an average particle size of 1.30 μm and a maximum particle size of 2.41 μm
An experiment was conducted in the same manner as in Example 1 using iron fine powder having m ² , specific surface area 15.3 / mm ² and specific gravity 7.9, and it was difficult to make the core layer material into chips, and the spinnability was also poor. .

Example 11 Five monofilaments obtained in Example 1 were combined 21
Thirty 00 denier yarns were used to make a net on a Russell knitting machine, treated in hot water at 90 ° C, dried, and heat-treated at 170 ° C. The net-making property was good, the obtained net had a fast sedimentation speed in seawater, little net swaying due to waves, was suitable as a fishing net, and was excellent in durability.

[0060]

Industrial Applicability According to the present invention, there is provided a polyester fiber for marine products which is excellent in hydrolysis resistance and amine decomposition resistance, has high specific gravity and high strength. A fishing net using this fiber has excellent sedimentation properties, less shaking in the water, excellent fishing operability, and excellent durability.

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[Procedure amendment]

[Submission date] December 5, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

The yarn which has been solidified by cooling is stretched after or once it has been wound up. Stretching can be performed in a single stage or in multiple stages of two or more stages, but a two-stage stretching method is usually employed. That is, the stretching point does not move 65
Using a heating roller of the liquid bath at a temperature of ~ 100 ° C. or 100 to 200 DEG ° C. oven or 70 to 110 ° C., stretched first stage in 3-6 times magnification, and then 130 to the temperature higher than the first step stretching
It is preferable to use a 270 ° C. liquid bath, an oven, or a heating roller to perform the second stage stretching so that the total stretching ratio is 5 to 7 times. At this time, the total draw ratio is set to be higher than the first-stage draw ratio. If the drawing temperature is too low, the heating of the fiber will be insufficient, which will cause movement of the drawing point, yarn breakage, and yarn unevenness.If the drawing temperature is too high, superdraw phenomenon and fiber melting will occur, and the molecules will be oriented for drawing. Becomes difficult. Further, if the total draw ratio is less than 5 times, the yarn quality of the obtained fiber, particularly the linear strength, becomes low, and if it exceeds 7 times, voids are generated in the fiber and satisfactory yarn quality performance is not only exhibited. There is also no knot strength.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

The stretched yarn was heated at a temperature of 220 to 500 ° C. or a heating roller at 150 to 250 ° C. to a relaxation ratio of 3 to
Relaxation heat treatment of 15% is applied. If the temperature of the relaxation heat treatment is too low, the heat treatment effect on the fiber will be insufficient, and if the temperature of the relaxation heat treatment is too high, the thermal decomposition and deterioration of the polymer will occur on the fiber surface, and a fiber satisfying the target yarn quality performance can be obtained. Absent. Further, if the relaxation rate is less than 3%, the fiber has a high heat shrinkage rate and becomes unsuitable for practical use, and if it exceeds 15%, yarn sagging occurs in the relaxation heat treatment stage, resulting in poor operability and the target yarn. It does not show quality performance.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

Example 1 35% by weight of polyethylene terephthalate having a relative viscosity of 1.560 and a carboxyl end group amount of 17.5 eq / t and an average particle size of 0.63 μm,
65% by weight of tungsten fine powder having a maximum particle size of 1.30 μm, a specific surface area of 2.9 mm ² / g and a specific gravity of 19.3 was melt-kneaded and made into chips to obtain chips for core layer material having a specific gravity of 3.4. This core layer material chip is supplied to an extruder and melted at 270 ° C, while the relative viscosity is 1.560 and the carboxyl end group amount is 17.5.
eq / t polyethylene terephthalate chip with bis (2,6
-Diisopropylphenyl) carbodiimide was added in an amount of 1.0% by weight and supplied to another extruder, and melted at 295 ° C to form a sheath layer material, which was then composite-spun with the core layer material. In this case, the filtration of the molten polymer in the spinneret pack temperature 295 ° C., subjected to formation of rectifying and core-sheath structure composite stream, discharged from the spinning holes with a diameter of 1.3 mm, the core-sheath composite weight ratio 60
A / 40 concentric composite monofilament was used. After cooling the spun yarn in a 65 ° C water bath, it is passed through a heating medium bath at 100 ° C to draw 4.9 times, and then passed through an oven heater at 130 ° C to draw 1.16 times (total draw ratio). 5.7 times)
Furthermore, it was passed through an oven heater at 220 ° C and the relaxation rate
A relaxation heat treatment of 12% was performed to obtain a core-sheath composite monofilament. The yarn characteristics of the obtained monofilament are shown in Table 1.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

Example 2 Using the same core layer material and sheath layer material as in Example 1, the diameter was
It was discharged from a spinneret having 20 spinning holes of 0.6 mm to obtain a concentric composite multifilament having a core-sheath composite weight ratio of 60/40 . After blowing 20 ° C air on the spun yarn to cool it,
Draw 5.00 times using 90 ° C heated roller, then 2
Stretched to 1.27 times using a 40 ° C heating roller (total stretching ratio 6.
35 times) and further subjected to relaxation heat treatment at a relaxation rate of 6% using a heating roller at 170 ° C. to obtain a core-sheath composite multifilament. The yarn characteristics of the obtained multifilament are shown in Table 1.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0051

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Example 9 A core layer material having a specific gravity of 2.6 was obtained instead of the core layer material in Example 1 with a ratio of tungsten fine powder of 50% by weight, and the core-sheath composite weight ratio was 66/34 except that the core-sheath composite weight ratio was 66/34. A core-sheath composite monofilament was obtained in the same manner as in Example 1. The yarn characteristics of the obtained monofilament are shown in Table 1.

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[Table 1]

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Comparative Example 6 A high specific gravity powder having an average particle size of 1.30 μm and a maximum particle size of 2.41 μm
m, specific surface area 15.3 mm ² / g , using iron fine powder with a specific gravity of 7.9,
When an experiment was conducted in the same manner as in Example 1, it was difficult to form the core layer material into chips, and the spinnability was also poor. ─────────────────────────────────────────────────── ───

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[Submission date] December 16, 1994

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─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location D01F 6/92 F (72) Inventor Naoki Kanemoto 23 Uji Kozakura, Uji city, Kyoto unitika stock company Central Research Center

Claims (3)

[Claims] 1. The core layer has a specific gravity of 5 to 2 relative to polyester.
2. Mixture with specific gravity of 1.8 or more mixed with fine powder of metal and / or metal compound having specific surface area of 11 m ² / g or less, average particle size of 1 μm or less, and maximum particle size of 2 μm or less, carboxyl terminal group as sheath layer A core-sheath composite fiber obtained by melt spinning using a mixture of polyethylene terephthalate in an amount of 20 eq / t or less or a polyester mainly containing this with 0.3 to 2% by weight of a monocarbodiimide compound, drawn, and heat treated. For aquatic materials, characterized in that the amount of carboxyl end groups in the sheath layer is 5 eq / t or less, linear strength is 45 kg / mm ² or more, linear cutting elongation is 15% or more, knot strength is 30 kg / mm ² or more, and specific gravity is 1.7 or more. Polyester fiber. 2. The method for producing a polyester fiber for marine products according to claim 1, wherein the following steps are sequentially performed. (a) Polyester with a specific gravity of 5 to 22, a specific surface area of 11 m ² / g or less,
Metals with an average particle size of 1 μm or less and a maximum particle size of 2 μm or less and /
Alternatively, a step of uniformly dispersing fine powder of high specific gravity composed of a metal compound to obtain a core layer material having a specific gravity of 1.8 or more, (b) Polyethylene terephthalate having a carboxyl end group content of 20 eq / t or less, or a polyester mainly composed of this monocarbodiimide The compound was added in an amount of 0.3 to 2% by weight to form a sheath layer material and subjected to composite melt spinning together with the above core layer material, and the sheath layer had a carboxyl end group content of 5 eq / t or less and a fiber specific gravity of 1.7 or more. (C) Core-sheath composite unstretched fiber is stretched and heat-treated to obtain a linear strength of 45 kg / mm ² or more, a linear cutting elongation of 15% or more, a knot strength of 30 kg / mm ² or more, and a specific gravity of 1.7 or more. The step of obtaining the composite fiber. 3. A fishing net braided with the polyester fiber for marine products according to claim 1.