JPH055212A - Production of polyester fiber - Google Patents

Abstract

PURPOSE:To produce the subject fiber excellent in strength-elongation characteristics, thermal resistance, spinnability and productivity and useful for clothing, etc., by copolymerizing a monomer mixture containing neopentyl glycol component in a prescribed amount based on the whole dicarboxylic acid components constituting the polyester and spinning the resultant copolyester in a specified condition. CONSTITUTION:A polyester mainly composed of ethylene terephthalate as its repeating unit and containing neopentyl glycol component copolymerized in an amount of 0.1-20mol% based on the whole dicarboxylic acid components constituting this polyester is subjected to ultra-high speed spinning at a take-off speed satisfying formula V<=(logd+6.5)X1000[V: take-off speed (m/min), d: single yarn fineness of taken-up yarn denier)], thus obtaining the objective fiber.

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 polyester fiber, and more particularly to a method for producing a polyester fiber having excellent physical properties by an ultra high speed spinning method.

[0002]

2. Description of the Related Art Polyester fibers, especially polyethylene terephthalate fibers, are widely used for clothing and industrial applications because of their excellent heat resistance, chemical resistance and mechanical properties.

A normal polyester fiber for clothing having a single yarn fineness of about 2 to 3 denier is formed by extruding molten polyester into a fibrous form from a spinning nozzle to obtain 1000 to 3500 m / min.
It is manufactured by winding at a take-up speed of minutes, followed by stretching, heat setting and the like. In recent years, due to advances in spinning technology and the like, a method of obtaining a polyester fiber having practically sufficient fiber physical properties only by a spinning step is being adopted by a high-speed spinning method with a take-up speed of around 6000 m / min. This high-speed spinning method has an advantage that not only the conventional stretching step is unnecessary but also the productivity is remarkably improved.

However, in the case where the single yarn fineness is about 2 to 3 denier, if the level of the take-up speed is raised in order to further improve the productivity, the mechanical properties of the obtained fiber, particularly the strength, are taken up at a take-up speed of 6000 m / min. The level near the maximum decreases, and the elongation also decreases (Jiro Shimizu et al., The Textile Society of Japan,
37 , T-135 (1981)). Further, when the single yarn fineness becomes small, the level of the take-up speed at which the mechanical properties of the obtained fiber are maximized is lowered. For example, the single yarn fineness is 0.
When it is attempted to obtain ultrafine fibers of 3 denier, the take-up speed at which the mechanical properties of the obtained fiber are maximized decreases to a level of about 5000 m / min.

Therefore, the mechanical properties of the fiber obtained by adopting the ultra-high speed spinning method, which is a level of the take-up speed far exceeding the take-off speed of the level of about 5000 to 6000 m / min used in the high-speed spinning method, are improved. There was a problem that it would decrease. In order to solve this problem, a method of copolymerizing paraoxybenzoic acid with polyester (JP-A-59-47423), a method of adding a silver compound (JP-A-59-100714), polymethylmethacrylate, etc. Method of adding the polymer of
No. 21817), a method of copolymerizing bis (4-carboxyphenoxy) ethane (Japanese Patent Laid-Open No. 63-19001).
No. 5 publication) is proposed. However, these improving effects were not sufficient and were not at a satisfactory level.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a polyester fiber which is excellent in mechanical properties, that is, strength and elongation characteristics at the same time by the above-mentioned ultra-high speed spinning method. Another object of the present invention is to provide a method for producing a polyester fiber in which troubles such as yarn breakage and single yarn breakage are less likely to occur even when spun by an ultra high speed spinning method.

[0007]

The above-mentioned object of the present invention is a polyester having ethylene terephthalate as a main repeating unit, wherein the neopentyl glycol component is 0.1 to 0.1% with respect to all dicarboxylic acid components constituting the polyester. It can be achieved by a method for producing a polyester fiber, which comprises spinning a polyester copolymerized with 20 mol% at a take-up speed satisfying the following formula. V ≧ (logd + 6.5) × 1000 V: take-up speed (m / min) d: single yarn fineness (denier) of take-up yarn The present invention will be described in detail below. The polyester of the present invention has ethylene terephthalate as the main repeating unit. In addition to the terephthalic acid component as the dicarboxylic acid component,
For example, aliphatic dicarboxylic acid components such as adipic acid, sebacic acid and dimer acid, aromatic dicarboxylic acid components such as isophthalic acid and 2,6-naphthalenedicarboxylic acid,
An alicyclic dicarboxylic acid component such as 1,4-cyclohexanedicarboxylic acid may be used in combination without departing from the object of the present invention. Further, as the diol component for the polyester main chain, for example, 1,4-butanediol, 1,6
A diol component such as -hexanediol, polyethylene glycol, polytetramethylene glycol, and 1,4-cyclohexanedimethanol may be used in combination without departing from the object of the present invention.

The polyester of the present invention is required to copolymerize, as a copolymerization component, a neopentyl glycol component in an amount of 0.1 to 20 mol% with respect to all dicarboxylic acid components constituting the polyester. By copolymerizing polyethylene terephthalate with this neopentyl glycol component, in the ultra-high-speed spinning method, oriented crystallization is suppressed, so that it is possible to obtain a polyester fiber having excellent strength and elongation properties at the same time, and It is possible to reduce the occurrence of troubles such as yarn breakage and single yarn breakage in ultra high speed spinning.

The copolymerization rate of the neopentyl glycol component in the present invention is required to be 0.1 to 20 mol%, preferably 2 to 17 mol%, more preferably 6 to 13 mol%. preferable. If it is less than 0.1 mol%, the effect of improving the mechanical properties and spinnability of the obtained fiber will be small, and if it exceeds 20 mol%, the melting point of the obtained fiber will be low and the heat resistance will be low.

In the polyester of the present invention, an oxycarboxylic acid component such as paraoxybenzoic acid or ε-caprolactone may be copolymerized within the range not departing from the object of the present invention, and polyerythritol, trimellitic acid or the like may be copolymerized. The functional component may be copolymerized to the extent that the polyester is substantially linear. In addition, various additives, such as
If desired, a matting agent, a flame retardant, an antioxidant, an ultraviolet absorber, an infrared absorber, a crystal nucleating agent, a fluorescent brightening agent, a terminal group blocking agent, etc. may be copolymerized or mixed.

The polyester of the present invention is usually produced by the esterification reaction of terephthalic acid and ethylene glycol, the transesterification reaction of dimethyl terephthalate and ethylene glycol, or the addition reaction of terephthalic acid and ethylene oxide. Ethyl terephthalate) and / or a low polymer thereof and then polycondensation thereof under heating and reduced pressure until a predetermined degree of polymerization is obtained. In any stage before the completion of the polycondensation reaction, neopentyl glycol can be added to the above reaction system and copolymerized. At that time, neopentyl glycol may be added as it is or after being dispersed, dissolved, or heat-treated in a suitable solvent such as ethylene glycol.

The polyester thus obtained is subjected to melt spinning. In the melt spinning in the present invention, the take-up speed (V: m / min) is a single yarn fineness (d: denier) of the take-up yarn.
In contrast, the take-up speed that satisfies V ≧ (logd + 6.5) × 1000. When the polyester of the present invention is spun at a take-up speed satisfying the above formula, the spinning tension becomes appropriate, and a polyester fiber having excellent strength and elongation properties at the same time can be obtained. The fiber spun at a speed lower than this take-up speed has a low yield point stress, and therefore has a problem of being plastically deformed when a high tension is applied in a higher-order process, and cannot be used for ordinary woven or knitted fabric applications. 1500
If a take-up speed exceeding 0 m / min is adopted, yarn breakage tends to increase, so the upper limit of the take-up speed is preferably set to 15000 m / min.

Although the reason why the fiber obtained by the method of the present invention is excellent in physical properties is not clear, the polyester of the present invention is obtained by copolymerizing a large amount of a component having a relatively low molecular weight and a suitable bulkiness. Since oriented crystallization is suppressed in the spinning process, it is considered that the fiber having excellent physical properties can be obtained only by adopting the ultrahigh-speed spinning method with high tension.

[0014]

The present invention will be described in detail below with reference to examples. Each characteristic value in the examples was determined according to the following method. (A) Intrinsic viscosity: Orthochlorophenol solution, 25
It was measured at ° C. (B) Copolymerization rate of copolymerization component: The polymer was decomposed with a sodium methylate / methanol solution and measured by liquid chromatography. (C) Melting point: measured with a Perkin-Elmer DSC-4 model at a sample amount of 10 mg and a heating rate of 10 ° C./min. (D) Fiber strength and elongation: Tensilon tensile tester manufactured by Toyo Baldwin Co., Ltd., sample length 20 cm, tensile speed 2
It was determined from the load extension curve obtained at 0 cm / min. (E) Rate of increase in strength and elongation of fiber: Strength (K) and elongation (S) of fiber obtained by spinning copolymerized polyester, and the same single yarn fineness and the same take-up speed It was determined by the following formula from the strength (K ₀ ) and elongation (S ₀ ) of ordinary polyethylene terephthalate fiber not copolymerized. Strength increase rate (%) = (K−K ₀ ) / K ₀ × 100 Elongation increase rate (%) = (S−S ₀ ) / S ₀ × 100 Reference Example 1 166 parts by weight of terephthalic acid and 75 parts by weight of ethylene glycol Part of the low polymer obtained by the usual esterification reaction with 0.03% of a 85% aqueous solution of orthophosphoric acid as a coloring inhibitor.
Parts by weight, 0.06 of antimony trioxide as a polycondensation catalyst
Parts by weight, 0.06 parts by weight of cobalt acetate tetrahydrate as a toning agent is added to carry out a polycondensation reaction, an intrinsic viscosity of 0.62,
A commonly used polyethylene terephthalate having a melting point of 256 ° C. was obtained. Using this polymer, melt drawing was carried out at 300 ° C. while changing the take-up speed to obtain a polyester fiber of 50 denier / 24 filament (single yarn fineness of 2.08 denier). The strength and elongation of the obtained fiber are shown in Table 1.
The strength has a maximum value at a take-up speed of 6000 m / min, and a large decrease occurs at a take-up speed exceeding it. Further, the elongation decreases as the take-up speed increases, and the extent of the decrease is large.

[0015]

[Table 1]

Example 1 A low polymer obtained by a usual esterification reaction from 166 parts by weight of terephthalic acid and 75 parts by weight of ethylene glycol was mixed with 0.03% of an aqueous solution of 85% orthophosphoric acid as a coloring inhibitor.
Parts by weight, 0.06 of antimony trioxide as a polycondensation catalyst
Parts by weight, 0.06 parts by weight of cobalt acetate tetrahydrate as a toning agent and 13 parts by weight of neopentyl glycol are added to carry out a polycondensation reaction, an intrinsic viscosity of 0.61, a melting point of 235 ° C.
Polyester obtained by copolymerizing 10 mol% of neopentyl glycol was obtained. This polymer was melt-spun at 300 ° C. while changing the take-up speed to obtain a polyester fiber of 50 denier / 24 filament (single yarn fineness of 2.08 denier). Table 2 shows the strength increase rate and the elongation increase rate obtained by comparing the strength and the elongation of the obtained fiber with those values in Table 1 obtained in Reference Example 1. As is clear from Table 2, the range of the take-up speed of the present invention, that is, (log
It is understood that the polyester fiber obtained at 2.08 + 6.5) × 1000 = 6820 m / min or more has a large rate of increase in strength and elongation, and has practically sufficient fiber physical properties.
On the other hand, if the take-off speed of the present invention is out of the range,
Only fibers with a lower strength were obtained than the non-copolymerized polyester fibers obtained at the same take-off speed.

[0017]

[Table 2]

Example 2 A copolymerized polyester was obtained in the same manner as in Example 1 except that the copolymerization component or the copolymerization amount was changed. The intrinsic viscosity and melting point of the obtained copolyester are shown in Table 3. These polymers were melt-spun at 300 ° C. while changing the take-up speed to obtain polyester fibers of 50 denier / 24 filament (single yarn fineness of 2.08 denier). Table 4 shows the strength increase rate and the elongation increase rate obtained by comparing the strength and the elongation of the obtained fiber with those values in Table 1 obtained in Reference Example 1. As is clear from Table 4, the ultra-high-speed spun fibers obtained from the polymers B, C and D, which are the copolyesters of the present invention, have an increase rate of strength and elongation of 1
It is as large as 0% or more, and it can be seen that the fiber properties are practically sufficient. On the other hand, Polymer A having a copolymerization component of less than 0.1 mol% and Polymers E and F having a copolymerization component different from that of the present invention have an increase rate of strength or elongation of less than 10%, and thus mechanical There was no effect of improving the physical properties.

[0019]

[Table 3]

[0020]

[Table 4]

Reference Example 2 Using the polyethylene terephthalate obtained in Reference Example 1,
Melt-spun at 300 ° C with different take-up speed, 36 denier / 120 filament (single yarn fineness 0.30 denier)
Of polyester fiber was obtained. The strength and elongation of the obtained fiber are shown in Table 5. The strength has a maximum value at a take-up speed of 5000 m / min, and a large decrease occurs at a take-up speed exceeding it. Further, the elongation decreases as the take-up speed increases, and the extent of the decrease is large.

[0022]

[Table 5]

Example 3 The copolyester obtained in Example 1 was melt-spun at 300 ° C. while changing the take-up speed to obtain 36 denier / 120 filaments (single yarn fineness 0.30 denier) polyester fiber. Table 6 shows the strength and elongation of the obtained fiber, the values thereof, and the rate of increase in strength and the rate of increase in elongation determined by comparison with Table 5 obtained in Reference Example 2. As is clear from Table 6, the range of the take-up speed of the present invention, that is, (log 0.30 + 6.5) × 1000 = 5980
It can be seen that the polyester fiber obtained at m / min or more has a large increase rate of strength and elongation and has practically sufficient fiber physical properties. On the other hand, when the take-off speed range of the present invention was out of the range, only fibers having a lower strength than the non-copolymerized polyester fibers obtained at the same take-up speed were obtained.

[0024]

[Table 6]

[0025]

According to the method of the present invention, not only the strength characteristics but also the elongation characteristics are excellent at the same time by adopting an ultra-high speed spinning method that exceeds the take-up speed adopted in the conventional high-speed spinning method. Moreover, since it is possible to provide a polyester fiber having excellent heat resistance and spinnability, the productivity of the polyester fiber can be remarkably improved by adopting the ultra-high speed spinning method.

Claims (1)

Claim: What is claimed is: 1. A polyester comprising ethylene terephthalate as a main repeating unit, wherein 0.1 to 20 mol% of neopentyl glycol component is copolymerized with all dicarboxylic acid components constituting the polyester. A method for producing a polyester fiber, comprising spinning the obtained polyester at a take-up speed satisfying the following formula. V ≧ (logd + 6.5) × 1000 V: take-up speed (m / min) d: single yarn fineness of take-up yarn (denier)