JPH1081811A - Polyester fiber having improved contact running wear characteristics and method for producing the same - Google Patents

Abstract

(57) [Summary] [Problem] Even if titanium dioxide is added at a high concentration, damage to the yarn-joining portion where the fiber runs is small, and high quality with excellent processability such as spinning, false twisting, weaving, etc. To provide polyester fiber. SOLUTION: Polysiloxane having a viscosity of 20,000 to 1,000,000 centistokes at 25 ° C. and titanium dioxide fine particles are dispersed in polyester fiber, and the content percentage by weight of the polysiloxane and titanium dioxide fine particles with respect to the fiber is determined. When A and B respectively, 1 ≦ B ≦
8. A polyester fiber having improved contact running wear characteristics, characterized by satisfying 0.25B ≦ A ≦ 4B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber to which titanium dioxide is added. More specifically, even if titanium dioxide is added at a high concentration, damage to a yarn-joining portion where the obtained fiber runs is reduced. The present invention relates to a high-quality polyester fiber which is low in the processability such as spinning, false twisting and weaving, and a method for producing the same.

[0002]

2. Description of the Related Art Titanium dioxide is added to polyester fibers to impart additional effects such as matting, transparency and hiding, ultraviolet shielding, fabric drape, and light resistance to polyester fibers. Has been performed conventionally.

[0003] Since titanium dioxide is generally added during the polymerization of polyester, it is well known that the quality of the dispersed state of titanium dioxide has a great effect on the operability of the polymerization step and the spinning step. If the dispersion state of titanium dioxide is poor and agglomeration exists, sedimentation occurs in the polymerization process,
Since the filter replacement frequency increases due to blockage of the filtration filter during spinning, and the spinning condition deteriorates, problems such as an increase in titanium dioxide dispersibility and a decrease in coarse particles have been devised.

[0004] For example, a device for increasing the dispersibility by coating metal oxide fine particles with alumina, silica, phosphorus pentoxide or the like (JP-B-56-42684, JP-B-56-42).
No. 685, JP-B-56-42686, JP-B-56-42687, JP-A-5-132611, etc.), and a device for reducing coarse particles (JP-A-50-21661).
126, JP-A-57-167407, JP-A-60-112849, etc.).

[0005] Even with these methods, when the added amount of titanium dioxide is low, the operability in the polymerization step and the spinning step can be improved to some extent. Since titanium dioxide is present on the fiber surface, the yarn-joining portion is easily worn in the yarn-forming step and the post-processing step, which causes fluff during the yarn-forming and deteriorates the operability during the weaving. In recent years, the spinning speed, false twisting speed, and weaving speed have all increased, and damage to the spinneret, yarn guide, false twist device, reed, and the like has become a serious problem that cannot be ignored.

In order to solve these problems, a method using inorganic particles having a low hardness (Japanese Patent Publication No. 43-228) has been proposed.
No. 78) and a device for suppressing damage by using titanium dioxide containing a phosphorus element and a potassium element (Japanese Patent Publication No.
No. 48704) has been proposed, but in this case, there remains a problem that the hue is yellowed in the spinning process and the spinning property is easily deteriorated. Further, a method of lowering the content of titanium dioxide in the fiber surface layer by composite spinning (Japanese Patent Publication No. Sho 63-17925, Japanese Patent Publication No. Sho 63-17926, etc.), or the use of fine particles having a small damage to the yarn-joining portion ( Combined use of carbonate particles: JP-A-54-151620, cross-linked hollow resin particles: JP-A-62-184109, etc. However, this method is costly and requires titanium dioxide in the fiber surface layer. The problem that the feeling improvement effect (for example, drapeability after alkali weight loss) utilizing the presence of the iron is reduced has been left unsolved.

Further, a so-called stock solution coloring method in which a liquid dispersion obtained by dispersing a colorant such as a pigment in a liquid dispersion medium is added to a melt of a polyester resin may be used for adding a function imparting agent such as titanium dioxide. Proposed.

Examples of the liquid dispersion medium for the polyester resin include a phosphorus-based dispersion medium such as tribiphenyl phosphate (Japanese Patent Publication No. Sho 62-241), and a polyhydric alcohol such as dipentaerythritol saturated fatty acid ester and an organic acid. Esters (JP-B-63-64531), polyoxyethylene alkyl phenyl ether (JP-B-6-6431)
Liquid polyesters such as poly (1,3-butylene adipate) (JP-A-60-456).
No. 89, JP-B 5-72428), epoxidized vegetable oil (JP-A-62-167349), and aliphatic polyesters whose terminals are blocked with alcohols (JP-B-5-72428).
No. 73146, JP-A-5-59613, etc., polyethers whose both ends are ester-blocked, ester-blocked polyoxyethylene alkyl ethers, polyetheresters, aliphatic diisocyanate-modified polyesters (JP-A-63-163) No. 120767, Japanese Unexamined Patent Publication No.
118678) and the like.

A method of adding a liquid dispersion obtained by uniformly dispersing and mixing fine particles such as titanium dioxide in these liquid dispersion media to a melt of a polyester resin is a liquid-liquid mixture of a liquid dispersion and a polyester melt. Therefore, the fine particles can be uniformly dispersed and the heat history can be reduced, which is advantageous in that stable physical properties can be easily secured.

[0010] However, although the above dispersion medium has a relatively good affinity for polyester and has a certain degree of heat resistance, when mixed with polyester, it reacts with the polyester by the heat of melt spinning to form the polyester. However, there is a problem in that a decrease in viscosity, coloration due to a decomposition product, and a decrease in mechanical properties are caused. In addition, according to the study by the present inventors, it has been found that when titanium dioxide is added to polyester at a high concentration, the effect of reducing the damage of the yarn joining portion where the fiber runs is hardly recognized.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the damage to the yarn joining portion where the fiber runs even when titanium dioxide is added at a high concentration, and to improve the processability of spinning, false twisting, weaving and the like. It is to provide a high quality polyester fiber excellent in quality.

[0012]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies and as a result, when titanium dioxide is added to polyester at a high concentration, the above-mentioned problem is caused by the fact that titanium dioxide is not Was found to be due to the tendency to re-aggregate during mixing with.

[0013] Then, further studies were conducted on a dispersant and a dispersant capable of suppressing the re-aggregation of titanium dioxide fine particles while ensuring heat resistance. As a result, the viscosity of the dispersant at 25 ° C was 20,000 to 1,000,000 cm. By using a Stokes polysiloxane and adding a mixture obtained by mixing and dispersing titanium dioxide fine particles in the polysiloxane to the polyester just before spinning after the completion of polymerization, there is no decrease in the viscosity of the polyester and no coloring due to decomposition products, Moreover, it was found that the above-described re-agglomeration was suppressed, and the effect of reducing damage to the yarn joining portion where the fiber traveled was remarkably exhibited.
The present invention has been completed.

That is, in the first invention of the present invention, a polysiloxane having a viscosity of 20,000 to 1,000,000 centistokes at 25 ° C. and titanium dioxide fine particles are dispersed in a polyester fiber, and the polysiloxane and titanium dioxide are dispersed. When the weight percentage of the fine particles with respect to the polyester fiber is A and B, respectively, 1 ≦ B ≦ 8, 0.25B
The present invention relates to a polyester fiber having improved contact running wear characteristics, which satisfies ≦ A ≦ 4B.

In a second aspect of the present invention, a mixture in which titanium dioxide fine particles are mixed and dispersed in a polysiloxane having a viscosity of 20,000 to 1,000,000 centistokes at 25.degree.
8, 0.25B ≦ A ≦ 4B (A and B are the weight percentages of polysiloxane and titanium dioxide fine particles with respect to the polyester fiber, respectively) added to the polyester just after the completion of the polymerization of the polyester-based polymer and just before the spinning. The present invention relates to a method for producing a polyester fiber having improved contact running wear characteristics, characterized by spinning.

In the present invention, the polyester is not particularly limited as long as it is a polyester having an aromatic group, and is an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, phthalic acid or the like. A polyester synthesized from these esters and a diol compound such as ethylene glycol, diethylene glycol, 1,4-butanediol, or neopentyl glycol, particularly a polyester in which 80% or more of the repeating structural units are polyethylene terephthalate. I do. Examples thereof include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene terephthalate and polytetramethylene glycol block copolymer, and polyester ether elastomers.

The polysiloxane used in the present invention includes:
Various organic silicone compounds can be used, and oils or raw rubbers such as dimethylpolysiloxane, diphenylpolysiloxane, and methylphenylpolysiloxane may be used alone or in combination of two or more.

The viscosity of the polysiloxane at 25 ° C. must be in the range of 20,000 to 1,000,000 centistokes. If the viscosity is lower than 20,000 centistokes, the titanium dioxide fine particles are likely to re-aggregate due to heat history when added at a high concentration in the polyester melt, so that the damage of the yarn joining portion where the obtained fiber runs increases. On the other hand, when the viscosity exceeds 1,000,000 centistokes, the viscosity is too high, and the effect of coating the titanium dioxide surface is reduced, and the particles are easily re-agglomerated. In addition, the compatibility with the polyester-based polymer becomes poor, and the fibers are easily broken during spinning, drawing, and false twisting due to the aggregated particles of polyethylene oxide in the fibers.

In consideration of these points, the viscosity at 25 ° C. of the polysiloxane used in the present invention is preferably from 50,000 to 50,000.
In the range of 1 million centistokes, more preferably 10
It ranges from 10,000 to 1 million centistokes.

As the titanium dioxide particles used in the present invention, any known titanium dioxide particles conventionally used for synthetic resins can be used. Even if the average particle size is as small as 0.5 μm or less, the particle size distribution is broad. For those with a large amount of coarse particles, stress concentration due to the coarse particles in the fiber occurs, and during spinning, drawing, and false twisting, the fiber is easily broken. As the particle diameter becomes larger or the single fiber denier becomes smaller, the stress concentration becomes larger.
It is preferable that the number of coarse particles of μm or more is as small as possible.

In the present invention, the mixing and dispersing mixture of the polysiloxane and the titanium dioxide fine particles can be prepared by a usual mixing method. However, a kneader capable of high-viscosity kneading capable of uniformly coating the surface of the titanium dioxide fine particles with the polysiloxane is used. It is preferable to select.

For example, an extruder having a kneading rotor or a blade, a twin-screw extruder of the same direction or a different direction, or a continuous kneading extruder such as a single-screw continuous kneader is used alone or in combination. do it. In particular, a method using a continuous kneading extruder provided with a plurality of powder and liquid inlets is preferable from the viewpoint of productivity.

Further, in a dispersion mixture comprising titanium dioxide fine particles and polyethylene oxide dispersant, and titanium dioxide fine particles, polyethylene oxide dispersant and PA
An antioxidant such as a hindered phenol or thioether can be added to the dispersion mixture composed of the G derivative.

The thus obtained dispersion mixture of titanium dioxide fine particles and polysiloxane has heat resistance, so that there is no decrease in viscosity or coloring due to decomposition products in the melt spinning step of the polyester, and it has a high affinity for the polyester. There is an advantage that titanium dioxide fine particles can be uniformly dispersed in polyester.

One of the features of the production method of the present invention is that a dispersion mixture comprising titanium dioxide fine particles and polysiloxane is
That is, it is added to and mixed with the polyester immediately before spinning. The term “immediately before spinning” means an arbitrary stage after the polymerization is substantially completed and before the spinning nozzle is discharged.

In the method of adding the dispersion mixture during the preparation or during the reaction of polyester polymerization, or in the method of producing a master batch in which the dispersion mixture is dispersed at a high concentration in a polyester resin and spinning, a titanium dioxide polyester is used. Although the effect of improving the dispersibility in the medium is recognized to some extent, the effect of reducing the contact running wear of the obtained fiber is not recognized or extremely small.

The dispersion mixture may be added to and mixed with the polyester after the completion of the polymerization in the polymerization reaction tank, in the middle of the outlet line from the polymerization reaction tank, in a screw compression zone or a measuring zone of an extruder. And dynamic kneading with a screw.

In the present invention, when the content weight percentages of the polysiloxane and the titanium dioxide fine particles with respect to the obtained polyester fiber are A and B, respectively,
≤ B ≤ 8, and 0.25B ≤ A ≤ 4B.

The content percentage by weight A of the polyethylene oxide with respect to the polyester fiber is the content percentage by weight B of the titanium dioxide fine particles with respect to the polyester fiber.
On the other hand, in the case of A <0.25B, when the titanium dioxide fine particles are added to the polyester melt at a high concentration, the titanium dioxide fine particles are likely to re-aggregate due to the heat history.
Damage to the yarn joining portion where the obtained fiber travels increases. Conversely, when A> 4B, the compatibility with the polyester-based polymer becomes poor, and the fiber is easily broken during spinning, drawing and false twisting due to aggregation of the polysiloxane itself in the fiber.

If the content B of the titanium dioxide in the polyester fiber is too large, secondary aggregation of the titanium dioxide in the polyester fiber tends to occur and it is difficult to obtain a uniform dispersion state. The increase in pack pressure due to filter clogging increases not only deteriorates the processability during spinning, false twisting, and weaving but also causes problems such as a decrease in fiber properties.

In melt-spinning the polyester fiber of the present invention, it is not necessary to employ any particular method and condition, but any method and condition may be used.

[0032]

It is known that a titanium dioxide pigment is treated with a low-molecular-weight polysiloxane to improve the dispersibility of titanium dioxide (low-viscosity organosilicone: Japanese Patent Publication No. Sho 60).
JP-A-3430, JP-A-4-187229, JP-A-4-190839, JP-A-7-113002
No. 2, silicone particle emulsion: Japanese Patent Publication No. 4-3
JP 8783, low viscosity siloxane: JP-B 7-620
76, JP-A-3-234735, etc.). However, the polysiloxane in the present invention is a treatment with a high-viscosity polysiloxane, which has not been conventionally proposed. Further, the polysiloxane not only facilitates the dispersion of titanium dioxide in the polyester (easy dispersibility), but also improves the dispersion after mixing the polyester. Dispersibility does not change due to heat history (reaggregation suppression)
In terms of features, the technical idea is completely different from the conventional concept of polysiloxane surface treatment of titanium dioxide.

Furthermore, the titanium dioxide surface-treated with the polysiloxane disclosed in the conventional gazette tends to be re-agglomerated due to the change in dispersibility after mixing of the polyester due to the heat history, and at the same time, the decrease in the intrinsic viscosity of the polyester and the decomposition. There is a problem that coloring by an object and reduction of mechanical properties are caused.
This recognizes the technical idea of the present invention that the conventional method mixes titanium dioxide treated with high-viscosity polysiloxane to ensure heat resistance and maintain the dispersibility of titanium dioxide. It is clear that he did not.

The effect of suppressing the re-aggregation of titanium dioxide and the effect of reducing the contact running abrasion of the fibers by the polyethylene oxide having a high viscosity average molecular weight is a fact that has not been found so far. It is presumed that polysiloxane forms an adsorption layer having high thermal stability on the surface of titanium dioxide, and that re-aggregation between titanium dioxides is suppressed even when a high concentration of titanium dioxide is contained.

[0035]

According to the polyester fiber of the present invention, even when titanium dioxide is added at a high concentration, the titanium dioxide does not re-aggregate in the polyester, the damage of the yarn joining portion where the fiber runs is reduced, and the polyester fiber is spun. Damage to the die, yarn guide, false twist device, reed, etc. is small, and the processability of spinning, false twisting, weaving, etc. is excellent. In addition, it does not cause a decrease in the intrinsic viscosity of the polyester during spinning, coloring due to decomposition products, or a decrease in mechanical properties.It is added immediately before spinning, so it is extremely easy to clean in terms of brand switching and contamination, and costs are reduced. There is also an advantage that it is economically advantageous.

[0036]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

In Examples and Comparative Examples, the polysiloxane had a viscosity of 1000 to 10 at 25 ° C.
"KF-96" and "KF-96H" manufactured by Shin-Etsu Chemical of 10,000 centistokes were used.

Further, (1) dispersibility of titanium dioxide in the cross section of polyester fiber, (2) intrinsic viscosity of undrawn yarn, (3) whiteness index of drawn yarn tubular knitting, (4) contact running of drawn yarn The evaluation of wear characteristics was performed by the following method.

(1) Dispersibility of titanium dioxide in cross section of polyester fiber: A very small amount of polyester fiber is placed on a carbon support and immersed in an o-chlorophenol solvent at 80 ° C. for 8 hours to dissolve the polyester. After removing and drying, it was observed with a scanning electron microscope (JSM-5300, manufactured by JEOL datum) by an ordinary method. Those in which no aggregated particles of 1 μ or more were observed were classified as Class 5 and evaluated on a scale of 1 to 5.

(2) Intrinsic viscosity (IV) of undrawn yarn: 0.6 g of a sample was dissolved in 50 ml of o-chlorophenol to form a solution, and the solution was measured at 35 ° C. The unit was expressed in dl / g.

(3) Whiteness index W of drawn tubular knitting: two drawn yarns are combined into a 150 knit tube, JIS-Z8
The lightness index L * and the chromatech index b * value specified in 722 and JIS-Z8727 were measured, and W = L
The whiteness index W was determined according to * -b *.

(4) Contact running wear characteristics of the drawn yarn: 75d
e / 36fil filament on copper wire of 2mmφ diameter while applying 5g tension, contact angle 180 °, running speed 3
After running in for 5 minutes at 00 m / min, the running position was changed and the vehicle was run for 20 minutes, and the depth of the wear concave portion at the copper wire running entrance side position was determined. The same operation was repeated three times to obtain an average value. Practically, it is necessary that the thickness be 100 μm or less.

Reference Example 1 Dimethyl terephthalate 100
Parts, ethylene glycol 60 parts, calcium acetate monohydrate 0.063 parts (0.06 parts based on dimethyl terephthalate)
9 mol%) and cobalt acetate tetrahydrate 0.0
09 parts (0.007 mol% based on dimethyl terephthalate) were charged into a transesterification vessel, and the temperature was increased from 140 ° C. to 220 ° C. over 4 hours in a nitrogen gas atmosphere, and methanol produced was distilled out of the system. A transesterification reaction was performed while performing the reaction. Then, after stirring at 220 ° C. for 20 minutes, 0.058 parts of trimethyl phosphate (0.080 mol% based on dimethyl terephthalate) as a stabilizer was added, and at the same time, the temperature of the excess ethylene glycol was started to be removed. After 10 minutes, 0.04 parts of antimony trioxide (0.027 mol% based on dimethyl terephthalate) was added as a polycondensation catalyst.
Subsequently, when the internal temperature reached 240 ° C., the expulsion of ethylene glycol was terminated, and the reaction product was transferred to a polymerization vessel.
Then, the reaction was carried out at normal pressure while the temperature was raised until the internal temperature reached 260 ° C., and then it was changed from 760 mmHg to 1 mm over 1 hour.
Hg, and at the same time, raise the internal temperature to 28 over 1 hour and 30 minutes.
The temperature was raised to 0 ° C. The reaction was continued under a reduced pressure of 1 mmHg or less at a polymerization temperature of 280 ° C. until the intrinsic viscosity became 0.64 dl / g. The obtained polymer was discharged, water-cooled and cut to obtain a polyethylene terephthalate chip containing no titanium dioxide. The obtained polyester chips containing no titanium dioxide were dried with hot air at 160 ° C. for 5 hours and then melted at 290 ° C. with an extruder. The polyester polymer melt is measured by a gear pump, guided to a die at 285 ° C., extruded from a die having a number of 36 round hole extrusion nozzle holes having a hole diameter of 0.3 mm and a land length of 0.60 mm, and taken up at a spinning speed of 3,500 m / min. Was. Thereafter, the undrawn yarn is drawn and heat-treated at a draw ratio at which the elongation of the finally obtained drawn yarn is 30% using a supply roller at 90 ° C. and a heating roller at 130 ° C. to remove titanium dioxide. A drawn yarn of 75 denier / 36 filaments not containing was obtained.

The intrinsic viscosity of the undrawn yarn is 0.62 dl / g,
The whiteness index W of the drawn yarn tube knitting is 89.7, and the drawn yarn strength is 4.
7 g / de, the depth of the copper wire running wear concave portion of the fiber was 0 μm, and no wear was observed.

REFERENCE EXAMPLE 2 30 parts of titanium dioxide (KA-35WS manufactured by Titanium Industry Co., Ltd.) having an average primary particle diameter of 0.2 μm and 70 parts of ethylene glycol were charged with stirring.
The mixture was dispersed and mixed using a homogenizer. Next, the mixture was treated with a sand grinder pulverizer and a high-speed rotating decanter classifier, and then filtered through a filter having a nominal opening of 1 μ to prepare an ethylene glycol dispersion mixture. 100 parts of dimethyl terephthalate, ethylene glycol 70
Parts, manganese acetate 0.0 based on dimethyl terephthalate
25 mol% was charged into a transesterification vessel, and the temperature was raised from 150 ° C. to 250 ° C. over 4 hours in a nitrogen gas atmosphere, and a transesterification reaction was carried out while distilling off the generated methanol to the outside of the system. At that time, the ethylene glycol dispersion mixture of titanium dioxide prepared above was added so that titanium dioxide was 0.5% per polyester. After the transesterification reaction, 25 parts of trimethyl phosphate and 75 parts of ethylene glycol as stabilizers were heated and refluxed at 150 ° C. for 5 hours in a closed system, and the ethylene glycol solution of trimethyl phosphate prepared was converted into dimethyl terephthalate in terms of trimethyl phosphate. , And at the same time, the temperature was increased and the excess ethylene glycol was removed. After 10 minutes, 0.030 mol% of antimony trioxide as a polycondensation catalyst was added to dimethyl terephthalate, and the resulting reaction product was transferred to a polymerization vessel. The temperature was gradually raised from 230 ° C to 280 ° C, and gradually shifted from normal pressure to reduced pressure.
The polycondensation reaction was performed under a high vacuum of not more than mmHg. The obtained polymer was discharged, cooled with water, and cut to obtain a chip of polyethylene terephthalate containing 0.5% of titanium dioxide.

In Reference Example 1, a drawn yarn of 75 denier / 36 filaments was obtained by performing the same operation except that the polyester chip obtained by the above operation was used.

The intrinsic viscosity of the undrawn yarn is 0.62 dl / g,
The whiteness index W of the drawn yarn tube knitting is 88.7, and the drawn yarn strength is 4.
6 g / de, dispersibility of titanium dioxide in cross section of drawn yarn is 5
The depth of the copper wire running wear concave portion of the grade and the fiber was 20 μm.

Comparative Example 1 Titanium dioxide was prepared in the same manner as in Reference Example 2, except that an ethylene glycol dispersion mixture of titanium dioxide was added so that titanium dioxide was 2.5% per polyester. 2.5%
A drawn yarn containing 75 denier / 36 filaments was obtained.

The intrinsic viscosity of the undrawn yarn is 0.62 dl / g,
The whiteness index W of the drawn yarn tube knitting is 83.3, and the drawn yarn strength is 4.
4 g / de, dispersibility of titanium dioxide in cross section of drawn yarn is 3
The depth of the copper wire running wear concave portion of the grade and the fiber was 140 μm.

Comparative Example 2 Titanium dioxide was reduced to 5% by the same procedure as in Reference Example 2, except that an ethylene glycol dispersion mixture of titanium dioxide was added so that titanium dioxide was 5% per polyester. A drawn yarn containing 75 denier / 36 filaments was obtained.

The intrinsic viscosity of the undrawn yarn is 0.62 dl / g,
The whiteness index W of the drawn yarn tube knitting is 82.3, and the drawn yarn strength is 4.
1 g / de, dispersibility of titanium dioxide in cross section of drawn yarn is 2
The depth of the copper wire running wear concave portion of the grade and the fiber was 210 μm.

Example 1 Titanium dioxide (KA-35WS, manufactured by Titanium Industry Co., Ltd.) 50 having an average primary particle diameter of 0.2 μm
Part, 50 parts of a polysiloxane having a viscosity of 100,000 centistokes at 25 ° C. was mixed with a continuous kneading extruder (KCK 7).
0-22VEX type), kneading temperature 40 ° C, rotation speed 60r
By kneading and dispersing the mixture at pm, a slurry-like mixture of titanium dioxide was obtained.

The slurry was measured by a gear pump via a pipe heated to 100 ° C., and was adjusted to 10.0 parts by weight with respect to the mixed polymer melt from an injection port provided in a compression zone of an extruder. The polymer melt in the single screw extruder was injected under pressure and kneaded. The mixed polyester polymer melt was measured by a gear pump and led to a die at 285 ° C.
Extruded from a die having 3mmφ, land length 0.60mm, a round hole extrusion nozzle with 36 holes, spinning speed 3500
Withdrawn at m / min. Then, the undrawn yarn is drawn at 90 ° C. at a draw ratio at which the elongation of the finally obtained drawn yarn is 30%.
Using a supply roller and a heating roller at 130 ° C,
By heat treatment, a drawn yarn of 75 denier / 36 filaments containing 5.0% by weight of titanium dioxide and 5.0% by weight of polysiloxane was obtained.

The intrinsic viscosity of the undrawn yarn is 0.62 dl / g,
The whiteness index W of the drawn yarn tube knitting is 90.5, and the drawn yarn strength is 4.
4 g / de, dispersibility of titanium dioxide in cross section of drawn yarn is 5
The depth of the copper wire running wear concave portion of the class and the fiber was 50 μm.

[Examples 2 to 6, Comparative Examples 3 to 6]
In the above, except that the viscosity of the polysiloxane was changed, the same operation was performed to obtain a drawn yarn of 75 denier / 36 filaments. Table 1 shows the intrinsic viscosity of the undrawn yarn, the whiteness index W of the drawn yarn tube knitting, the drawn yarn strength, the dispersibility of titanium dioxide in the cross section of the drawn yarn, and the depth of the copper wire running wear concave portion of the fiber.
Are shown together with the results of Example 1, Reference Examples 1 and 2, and Comparative Examples 1 and 2.

Examples 7 to 9 and Comparative Example 7 The same operation as in Example 1 was carried out except that the amount ratio of titanium dioxide and polysiloxane and the injection amount with respect to polyester were changed. Was obtained. Table 1 shows the intrinsic viscosity of the undrawn yarn, the whiteness index W of the drawn yarn knitting, the drawn yarn strength, the dispersibility of titanium dioxide in the cross section of the drawn yarn, and the depth of the copper wire running wear concave portion of the fiber.

As in Examples 1 to 9, a polysiloxane having a viscosity at 25 ° C. in the range of 20,000 to 1,000,000 centistokes was added in an amount of 25 to 400% by weight based on titanium dioxide.
The decrease in the intrinsic viscosity due to melt spinning of the fiber blended immediately before spinning with the titanium dioxide slurry treated in an amount within the range described above is small, the whiteness index of the drawn yarn knitting and the drawn yarn strength are good, and in the fiber Have a titanium dioxide dispersibility of 4
Aggregated particles of 1 μm or more in the fibers are hardly recognized in grades 5 to 5, the copper wire running wear concave depth is 50 to 90 μm, and even at a high concentration of titanium dioxide, there is no practical problem, It is clear that a remarkable effect is exhibited in reducing the contact running wear of the fiber.

On the other hand, a fiber blended with a titanium dioxide slurry treated with a polysiloxane having a viscosity of less than 20,000 centistokes as in Comparative Examples 3 to 6, and a polysiloxane as in Comparative Example 7 was added to titanium dioxide by 25%. In the fiber blended with the titanium dioxide slurry treated in an amount within the range of less than 10% by weight, the dispersibility of titanium dioxide in the fiber is 2nd to 3rd grade, and a large amount of aggregated particles of 1 μm or more are mixed. The depth of the wear concave portion is 150 to 170 μm, and the fiber to which titanium dioxide is added at a high concentration has a low level of processability.

Comparative Example 8 Titanium dioxide (KA-35WS, manufactured by Titanium Industry Co., Ltd.) 50 having an average primary particle size of 0.2 μm
Parts, 20 parts of a polysiloxane having a viscosity of 100,000 centistokes at 25 ° C., and 30 parts of a titanium dioxide-free polyester chip obtained in Reference Example 1 were mixed with a continuous kneading extruder (70-22 VEX type manufactured by KCK). Kneading temperature 2
The mixture was kneaded, dispersed and extruded at 60 ° C. and a rotation speed of 60 rpm, and was cooled and cut to obtain a polyester master batch containing 50 parts of titanium dioxide and 20 parts of polysiloxane.

Next, 90 parts of the titanium dioxide-free polyester chips obtained in Reference Example 1 and 10 parts of the masterbatch were mixed and dried with hot air at 160 ° C. for 5 hours.
It was melted at 290 ° C. in an extruder.

The mixed polyester polymer melt was measured by a gear pump and led to a die at 285 ° C., and the hole diameter was 0.3 mm.
φ, round hole extrusion nozzle with land length 0.60mm Number of holes 3
It was extruded from a die having 6 pieces and was taken off at a spinning speed of 3500 m / min. Thereafter, the undrawn yarn is drawn and heat-treated using a 90 ° C. supply roller and a 130 ° C. heating roller at a draw ratio at which the elongation of the finally obtained drawn yarn is 30%. Is 5% by weight and polysiloxane is 2%
A drawn yarn of 75 denier / 36 filaments containing weight% was obtained.

The intrinsic viscosity of the undrawn yarn is 0.60 dl / g,
The whiteness index W of the drawn yarn tube knitting is 86.5, and the drawn yarn strength is 4.
0 g / de, dispersibility of titanium dioxide in cross section of drawn yarn is 3
The depth of the copper wire running wear concave portion of the grade and the fiber was 140 μm.

[0063]

[Table 1]

As in Comparative Example 8, titanium dioxide obtained by treating a polysiloxane having a viscosity at 25 ° C. of 20,000 to 1,000,000 centistokes in an amount of 25 to 400% by weight based on titanium dioxide. In the fiber blended with the masterbatch, the titanium dioxide dispersibility in the fiber is tertiary, many agglomerated particles of 1 μm or more are mixed, the depth of the copper wire running wear recess is large, and the fiber with high concentration of titanium dioxide is added. Is clearly at a level where the process passability is poor.

It is not clear why the titanium dioxide masterbatch method (Comparative Example 8) has poor titanium dioxide dispersibility in fibers as compared with the titanium dioxide slurry method (Example 8), but a titanium dioxide masterbatch is produced. It is considered that the kneading temperature at the time is high and the viscosity at the time of kneading is low.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08L 83:04)

Claims (4)

[Claims] 1. Polyester having a viscosity of 20,000 to 1,000,000 centistokes at 25 ° C. and titanium dioxide fine particles are dispersed in polyester fiber, and the content percentage by weight of the polysiloxane and titanium dioxide fine particles with respect to the fiber. Are A and B, respectively, 1 ≦ B ≦
8. A polyester fiber having improved contact running wear characteristics, characterized by satisfying 0.25B ≦ A ≦ 4B. 2. The polyester fiber according to claim 1, wherein the viscosity at 25 ° C. of the polysiloxane is 100,000 to 1,000,000 centistokes. 3. A mixture obtained by mixing and dispersing titanium dioxide fine particles in a polysiloxane having a viscosity of 20,000 to 1,000,000 centistokes at 25 ° C., wherein 1 ≦ B ≦ 8, 0.25B ≦
A <4B (where A and B are the weight percentages of the polysiloxane and titanium dioxide fine particles with respect to the obtained polyester fiber, respectively) are added to the polyester after the completion of the polymerization of the polyester-based polymer and immediately before the spinning, and then spun. A method for producing a polyester fiber having improved contact running wear characteristics. 4. The method according to claim 3, wherein the viscosity of the polysiloxane at 25 ° C. is 100,000 to 1,000,000 centistokes.