JP2000096350A - Sheath-core type conjugate fiber having frictional melting-resistant performance and woven or knitted fabric using the fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheath-core type conjugate fiber having an improved frictional melting- resistant performance, scarcely generating melted marks, even when brought into pressurized contact with other materials and rubbed, hardly causing the generation of white powder due to the spouting of polyethylene from the core portion in a false-twisting process and having a good process-passing property by forming the core portion and the sheath potion from specific polymers, respectively. SOLUTION: The sheath-core type conjugated fiber wherein the melting point of the polymer of the core portion is lower than that of the polymer of the sheath portion. Therein, (A) the core portion polymer contains a polyethylene copolymer obtained using a metallocene-based catalyst, and (B) the sheath polymer comprises a thermoplastic polymer having a melting point of >=200 deg.C. The component A preferably has a melt flow rate of <=5.0 g/10 min. The component B is preferably a polyester containing ethylene terephthalate units as main units, such as polyethylene terephthalate. The conjugate fiber preferably has a core portion/sheath portion ratio of 1/4 to 1/10. The sheath-core type conjugate fiber is obtained by melt-spinning the polymers from a known nozzle for forming a sheath-core conjugate fiber and then preferably drawing the spun fiber in two stages.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core-in-sheath type composite fiber having friction-melting resistance, which is suitably used for, for example, sports clothing, and a woven / knitted fabric using the fiber.

[0002]

2. Description of the Related Art Woven and knitted fabrics knitted only from synthetic fibers such as polyester fibers and nylon fibers, especially when used as clothing such as sports clothing, are used on the surface of the clothing in a state of use such as sliding or falling. If the woven or knitted fabric is subjected to excessive abrasion, the woven or knitted fabric is melted due to the frictional heat, and there is a disadvantage that a hole is formed. Furthermore,
There is a problem that the user is sometimes abraded or burned. Such a problem has been particularly increased due to an increase in indoor sports grounds and artificial turf ball stadiums having a wooden floor in recent years.

[0003] Conventionally, various types of friction-melting processing have been applied to woven or knitted fabrics made of synthetic fibers. As a general example, a finishing agent containing silicone as a main component is applied to a woven or knitted fabric made of synthetic fibers to perform a surface treatment for improving the smoothness of the surface of the woven or knitted fabric and reducing frictional resistance. However, in this method, physical properties as a woven or knitted material are reduced due to occurrence of snagging or the like, and further, there is a disadvantage that smoothness is reduced due to repeated washing.

[0004] There is also a method in which cotton is mixed with synthetic fibers by twisting, weaving or knitting to prevent pits in a woven or knitted fabric. In this method, even if frictional heat is generated in the fibers, the cotton remains without melting, thereby preventing perforation. However, melting of the synthetic fibers is still undeniable, and melting marks of the synthetic fibers are generated on the surface of the woven or knitted fabric. Furthermore, it is difficult to dye the fibers uniformly because the synthetic fibers and cotton have different dyeing properties, and the number of steps is increased due to the necessity of a mixing step of the synthetic fibers and cotton, resulting in high costs. Will be invited.

[0005] Therefore, the present applicant has attempted to impart friction-fusing resistance to the raw yarn itself of a woven or knitted fabric. as a result,
The present applicant has found that a core-in-sheath type conjugate fiber having a polymer having a lower melting point than the polymer of the sheath portion in the core portion has excellent friction-melting resistance and disclosed in Japanese Patent Application Laid-Open No. 4-11006. are doing. Specifically, examples of the polymer of the sheath portion of the core-sheath type composite fiber include polyethylene terephthalate, nylon 66, nylon 6, and the like, and the polymer of the core portion includes polyethylene, polypropylene, nylon 12, and the like. Is illustrated. When the core-sheath type composite fiber is used for sports clothing, the difference in melting point between the core and the sheath is preferably 40 ° C. or more. here,
The fabric using the core-sheath type composite fiber using the ordinary polyethylene polymer having a melting point of about 130 ° C. in the core is subjected to a contact pressure friction for 3 seconds under a load of 6 kg by a rotor type friction melting test. And a cloth excellent in friction-melting resistance with almost no trace of melting.

[0006]

However, for use in sports clothing expected to slide on the floor, it is desired to further improve the friction melting resistance. In addition, by crimping the core-sheath type composite fiber, friction is reduced based on the bulkiness of the fiber, and the friction melting performance can be improved. However, when a crimp is developed by false twisting or the like, a normal polyethylene polymer having a melting point of about 130 ° C. used in the core is jetted out in the false twisting step, and a large amount of white powder is generated to increase productivity. There is a problem that it decreases. Therefore, there is a demand for a core-sheath composite fiber having good frictional melting performance and good passability in the false twisting step.

The present invention has been made to meet such a demand, and further improves the friction-melting performance of the core-in-sheath type composite fiber. It is an object of the present invention to provide a fiber which is less likely to generate white powder due to ejection of polyethylene at the core in the process and has good processability.

[0008]

Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 is a core-sheath type conjugate fiber in which the core polymer has a lower melting point than the sheath polymer. The core polymer contains a copolymerized polyethylene polymerized using a metallocene catalyst, and the sheath polymer has a melting point of 2%.
The core structure is a core-sheath type composite fiber having a friction-melting performance characterized by being a thermoplastic polymer of at least 00 ° C. Here, the melting point refers to a melting peak temperature in DSC measurement.

By increasing the melting point difference between the core and the sheath and increasing the viscosity of the core when the core is melted, the friction-melting performance of the core-sheath type composite fiber is exhibited most effectively. For this reason,
It is desirable to use a polymer having a low melting point as much as possible for the core portion. Among resins suitable for melt spinning currently used, polyethylene is mentioned as a polymer having a low melting point.

In the present invention, the core polymer contains polyethylene copolymerized with a metallocene catalyst. It is not clear why polyethylene copolymerized using this metallocene catalyst exhibits the following effects, but polyethylene copolymerized using a metallocene catalyst has a narrow molecular weight distribution and polyethylene having a uniform molecular weight. It is considered that the generation of white powder in the false twisting step can be reduced because the low-molecular weight component can be obtained and the low molecular weight component is small. In addition, by using a metallocene catalyst, a copolymerized polyethylene having a low melting point and an MFR of 17 g / 10 minutes or less can be obtained, so that the occurrence of friction melting can be suppressed and the generation of white powder in the false twisting step can be reduced. It is considered that an effect can be obtained.

[0011] The copolymerized polyethylene of the core may be a single composition of copolymerized polyethylene polymerized using a metallocene-based catalyst, or may be a polyethylene using a catalyst other than the metallocene-based catalyst. Or a mixture of two or more of them.

The above-mentioned core-sheath type conjugate fiber has excellent friction-melting resistance. Even when the fiber is brought into contact and rubbing as a woven or knitted material, almost no trace of melting is produced. The reason why the composite fiber of the present invention exhibits excellent friction melting resistance is not clear, but as disclosed in Japanese Patent Application Laid-Open No. 4-11006, the temperature of the core rises to near its melting point due to frictional heat. It is considered that the temperature rise of the sheath portion is delayed by the melting endothermic effect generated at this time. It is better to use polyethylene having a lower melting point than polypropylene having a higher melting point as the core, the friction-melting resistance is more effectively exhibited, and further, the copolymerized polyethylene having a reduced melting point shown in the present invention was used. In this case, it can be sufficiently understood from the fact that even more excellent friction melting resistance is exhibited. In other words, the core-sheath type conjugate fiber of the present invention has an effect of reducing the melting point of the polyethylene component of the core part constituting the conjugate fiber, thereby quickly absorbing the heat generated by friction from a low temperature and reducing the melt fracture of the sheath part. Is obtained.

In the invention according to claim 2, the copolymer polyethylene of the core has a density of 0.94 g / cm ³ or less and a melting point of 130 ° C. or less. If the melting point is 130 ° C. or less, the difference between the melting point of the resin of the sheath portion is sufficient,
Excellent friction melting resistance is obtained.

Alternatively, in the invention according to claim 3, the copolymer polyethylene of the core has a melt flow rate (MFR) of 17.0 g / 10 minutes or less. here,
In the present invention, the melt flow rate is defined as JIS K
Condition 4 of flow test method for 7210 thermoplastics
(Test temperature: 190 ° C., test load: 21.12 N)

When the MFR exceeds 17.0 g / 10 min, the core-sheath structure is destroyed in the false twisting step, the twisting step, etc. due to the low viscosity of the polyethylene component in the core, and the polyethylene in the core is ejected. It becomes white powder and the post-processability tends to be poor. In addition, the melt flow rate (MFR) of the copolymerized polyethylene of the core is 5.0 g / 10
It is more preferable that the time is not more than minutes.

The invention according to claim 4 of the present invention is a polyester in which the thermoplastic polymer in the sheath has ethylene terephthalate as a main repeating unit.

Further, in the invention according to claim 5, the composite ratio (volume ratio) of the core and the sheath is 1 / core / sheath.
1 to 1/15. For the purpose of securing the physical properties of the fiber, it is not preferable to increase the composite ratio of the core component.
It is preferably 1/15, particularly preferably 1/4 to 1/10. The core-sheath type composite fiber is obtained by melt-spinning using a known core-sheath composite spinning nozzle, and drawing, preferably two-stage drawing.

The fineness of the core-sheath type composite fiber is not limited, and may be any fineness. In addition, the fiber cross section is also circular,
Various modified cross-sections such as a triangular cross-section may be used, and a coloring pigment may be contained in at least one of the composite components to obtain a raw fiber.

As the thermoplastic polymer of the sheath,
Polyethylene terephthalate (melting point = 256 ° C.), nylon 66 (melting point = 265 ° C.) or nylon 6 (melting point = 2
24 ° C.) can be used, but polyesters having ethylene terephthalate as a main repeating unit are preferably used.

Typical examples of the polyester having ethylene terephthalate as a main repeating unit include polyethylene terephthalate obtained by using terephthalic acid or an ester-forming derivative thereof as a dicarboxylic acid component and ethylene glycol or an ester-forming derivative thereof as a diol component.

A polyester in which a part of the dicarboxylic acid component or diol component is replaced by another dicarboxylic acid component or diol component can also be used.

Other dicarboxylic acid components include isophthalic acid, 5-sulfoisophthalic acid metal salt, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, p-
Oxybenzoic acid and the like. Other diol components include 1,4-butanediol and C 2-10
Alkylene glycol, 1,4-cyclohexanedimethanol, polyalkylene glycol and the like.

Further, as long as the polyester is substantially linear, polycarboxylic acids such as trimellitic acid and pyromellitic acid, polyols such as pentaerythritol and trimethylolpropane, monohydric polyalkylene oxide, phenylacetic acid, etc. May be used.

Such a polyester can be synthesized by any known method. For example, in the case of polyethylene terephthalate, an esterification reaction between terephthalic acid and ethylene glycol or a reaction between dimethyl terephthalate and ethylene glycol is carried out. It is obtained by a method in which an exchange reaction is carried out to produce a glycol ester or a low condensate thereof, followed by polycondensation.

In the synthesis of polyester,
Known catalysts, antioxidants, coloring inhibitors, ether bond byproduct inhibitors, flame retardants and the like can be used, and these additives may be contained in the polyester.

Further, according to the invention of claim 6, a crimp having a crimp rate of 15% or more is provided. By performing such crimping, the friction is reduced based on the bulkiness of the fiber, and the friction melting resistance can be improved.

According to the invention of claim 7 of the present application,
A woven or knitted fabric woven or knitted from any of the above-described core-sheath type conjugate fibers, which is characterized in that a load of 10 kg in a rotor-type friction melting test and a contact pressure of 3 seconds substantially do not substantially cause a melting mark. It has a configuration. Note that the rotor-type friction melting test is a test based on JIS L1056 (Method B).

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to preferred examples and comparative examples. Table 1 shows the physical properties of polyethylene used for the core in the following Examples and Comparative Examples, and the friction-melting resistance of the obtained fibers.

Example 1 Polyethylene terephthalate (PET) having a relative viscosity of 1.6, a density of 1.38 g / cm ³ and a melting point of 256 ° C. was used as a polymer for the sheath. As the polymer of the core, a kernel (KF260) manufactured by Nippon Polychem Co., Ltd., which is a copolymerized polyethylene (PE) polymerized using a metallocene catalyst, was used.

Using such a sheath component and a core component,
Assuming that the core / sheath composite ratio (volume ratio) is PE / PET = 1/8,
Melt composite spinning was performed by a core-sheath composite spinning nozzle to obtain an undrawn yarn. Next, this undrawn yarn is stretched in two steps to obtain 109 dte
An x / 24 filament core-sheath composite fiber was obtained. The yarn production stability at the time of producing this core-sheath type composite fiber was good.

The obtained core-sheath type conjugate fiber is used as a raw yarn, and is subjected to temporary twisting under the conditions of Z twist 3043 T / M, overfeed rate 3.1%, twisting tension 15 to 16 g, and heater temperature (false twist temperature) 160 ° C. Twist processing was performed. The false twisted yarn obtained at a false twist temperature of 160 ° C. had a crimp rate of 27.1% and had excellent bulkiness. Using this false twisted yarn, it was knitted into a mock rody, which is a typical knitting structure, as a clothing for sports using a 20 gauge circular knitting machine, and dyed in the same dyeing process as ordinary polyester fibers. A knitted fabric excellent in volume feeling due to stretchability and bulkiness and having good sharpness was obtained.

Further, JIS L1 was added to the obtained dyed knitted fabric.
A rotor-type friction melting test (load: 10 kg, 3 seconds), which is a test based on 056 (Method B), was performed, but no piercing phenomenon was observed and there was no melting trace.

<Examples 2 and 3> Copolymerized polyethylene (PE) polymerized using a metallocene-based catalyst was used except that the copolymerized polyethylene was different in physical properties from Example 1. Fibers were produced as in Example 1. The obtained dyed knitted fabric was subjected to a rotor-type friction melting test (load: 10 kg, 3 seconds), but no perforation phenomenon was observed and there was no melting trace.

<Comparative Example 1> As a core, MFR (Melt Fl
ow Ratio) 9g / 10min, density 0.96g / c
m ³ , having a melting point of 130 ° C., except that it was changed to polyethylene polymerized using a Ziegler catalyst, and all were the same as in the above example, and subjected to melt composite spinning and stretching treatment.
A 109 dtex / 24 filament core-sheath composite fiber was obtained. The false-twisted yarn obtained by using the obtained core-sheath type composite fiber as a raw yarn and performing a false twisting treatment at a false twisting temperature of 160 ° C. in the same manner as the example had a crimp rate of 28.0%.

Using this false twisted yarn, knitting was performed in the same manner as in Example 1, and the obtained knit was dyed and finished. When the dyed knitted fabric was subjected to a rotor-type friction melting test, a load of 6
At 3 kg for 3 seconds, no perforation phenomenon was observed and no trace of melting was found, but at 10 kg of load for 3 seconds, traces of melting and cutting were observed.

<Comparative Example 2> As a core, MFR (Melt Fl
ow Ratio) is 22g / 10min and density is 0.919g / c
m ³ and a melting point of 84 ° C., except that the polyethylene was polymerized using a Ziegler catalyst, and the same as in the above example was performed.
A core-sheath composite fiber of 09 dtex / 24 filaments was obtained. The false-twisted yarn obtained by using the obtained core-sheath type composite fiber as a raw yarn and performing a false twisting treatment at a false twisting temperature of 160 ° C. in the same manner as in the example had a crimp rate of 13.1%.

Using the false twisted yarn, knitting was performed in the same manner as in Example 1, and the resulting knit was dyed and finished. When the dyed knitted fabric was subjected to a rotor-type friction melting test, a load of 6
At 3 kg for 3 seconds, no perforation phenomenon was observed and no trace of melting was found, but at 10 kg of load for 3 seconds, traces of melting and cutting were observed.

[0038]

[Table 1]

[0039]

As described above, the core-in-sheath conjugate fiber of the present invention has excellent friction-melting resistance, so that the woven or knitted fabric made of the fiber can be used, for example, even when used as sports clothing. Sliding or falling on wooden floors or artificial turf, it does not melt due to the frictional heat generated when excessive friction occurs, no holes or melting marks are generated, and the user may get burned. It does not injure the user and also has safety for the user.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Sakakura 4-1-2 Ushikawa-dori, Toyohashi-shi, Aichi Prefecture Inside the Toyohashi Works of Mitsubishi Rayon Co., Ltd. 1 No. 2 in the Mitsubishi Rayon Co., Ltd. Toyohashi Plant

Claims (7)

[Claims] The core polymer is a core-sheath type composite fiber having a lower melting point than the polymer of the sheath, and the polymer of the core is a copolymerized polyethylene polymerized using a metallocene catalyst. A core-sheath type conjugate fiber having friction-melting resistance, wherein the sheath polymer is a thermoplastic polymer having a melting point of 200 ° C. or more. 2. The core-sheath type composite fiber according to claim 1, wherein the copolymer polyethylene of the core has a density of 0.94 g / cm ³ or less and a melting point of 130 ° C. or less. 3. The core-sheath type composite fiber according to claim 1, wherein the copolymerized polyethylene of the core has a melt flow rate (MFR) of 17.0 g / 10 minutes or less. 4. The core-sheath composite fiber according to claim 1, wherein the thermoplastic polymer in the sheath is a polyester having ethylene terephthalate as a main repeating unit. 5. A composite ratio (volume ratio) of the core portion and the sheath portion.
The core / sheath type composite fiber according to any one of claims 1 to 4, wherein the core / sheath ratio is 1/1 to 1/15. 6. The core-sheath type composite fiber according to claim 1, wherein a crimp having a crimp rate of 15% or more is provided. 7. A woven and knitted fabric of the core-sheath type composite fiber according to any one of claims 1 to 6, wherein a load of 10 kg according to a rotor-type friction melting test does not substantially cause a melting mark by a contact pressure of 3 seconds. Woven and knitted fabrics.