阅读说明：本技术 一种高白度聚酯纤维 (High-whiteness polyester fiber ) 是由 成娟 胡永佳 陈彬彬 秦飞 望月克彦 于 2019-08-27 设计创作，主要内容包括：本发明公开了一种高白度聚酯纤维,该纤维中含有无机粒子和/或有机粒子,当纤维中含有无机粒子时,纤维中同时含有季铵碱成分,该纤维可以是单组分纺丝,也可以是芯鞘复合纺丝。本发明所述高白度聚酯纤维的制备方法简单,在纺丝加工阶段滤压上升少、组件寿命长、成本低。本发明聚酯纤维的白度高,白度WI值可达到80以上,且在没有紫外光照射时也能体现出高白度效果。(The invention discloses a high-whiteness polyester fiber, which contains inorganic particles and/or organic particles, wherein when the fiber contains the inorganic particles, the fiber simultaneously contains quaternary ammonium base components, and the fiber can be single-component spinning or core-sheath composite spinning. The preparation method of the high-whiteness polyester fiber is simple, the filtration pressure rise is little in the spinning processing stage, the service life of the component is long, and the cost is low. The polyester fiber has high whiteness, the whiteness WI value can reach more than 80, and the high whiteness effect can be realized when no ultraviolet light is irradiated.)

1. A high-whiteness polyester fiber characterized by: the fiber contains inorganic particles and/or organic particles; when the fiber contains inorganic particles, the fiber simultaneously contains quaternary ammonium hydroxide shown as a formula 1,

in the formula 1, the compound is shown in the specification,

in the formula 1, R₁、R₂、R₃、R₄Are respectively a group shown in a formula 2 or a formula 3,

in the formula (2), the first and second groups,

in the formula 3, the first step is,

in the formula 2, n is an integer of 0-17, and in the formula 3, m is an integer of 0-3.

2. The high-whiteness polyester fiber according to claim 1, wherein: the quaternary ammonium hydroxide is one or more of tetramethylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium hydroxide or tetrapropylammonium hydroxide.

3. The high-whiteness polyester fiber according to claim 1 or 2, wherein: the content of quaternary ammonium base in the fiber is 1-100 ppm relative to the weight of the fiber in terms of nitrogen element.

4. The high-whiteness polyester fiber according to claim 1 or 2, wherein: the particle diameter of the inorganic particles is 1.5 μm or less.

5. The high-whiteness polyester fiber according to claim 1 or 2, wherein: the inorganic particles are at least one of titanium dioxide, calcium carbonate, barium sulfate, zinc oxide, zirconium oxide and iron oxide.

6. The high-whiteness polyester fiber according to claim 5, wherein: the inorganic particles are rutile titanium dioxide.

7. The high-whiteness polyester fiber according to claim 1 or 2, wherein: the content of the inorganic particles is 2 to 20wt% with respect to the weight of the fiber.

8. The high-whiteness polyester fiber according to claim 1 or 2, wherein: the particle size of the organic particles is 3.0 μm or less.

9. The high-whiteness polyester fiber according to claim 1 or 2, wherein: the organic particles are organosilicone particles.

10. The high-whiteness polyester fiber according to claim 1 or 2, wherein: the content of the organic particles is 2 to 20wt% with respect to the weight of the fiber.

11. The high-whiteness polyester fiber according to claim 1 or 2, wherein: the fiber is a core-sheath type composite fiber, wherein the core component is polyester containing inorganic particles, and the sheath component is polyester containing organic particles.

12. The high-whiteness polyester fiber according to claim 10, wherein: the mass ratio of the core component to the sheath component is 20: 80-80: 20.

Technical Field

The present invention relates to a high-whiteness polyester fiber, and more particularly, to a high-whiteness polyester fiber containing inorganic particles and/or organic particles.

Background

Since the common polyester has many characteristics such as high strength, excellent mechanical properties, and easy processing, it is widely used.

The conventional whitening process adopted by the common polyester fabric comprises the change of the concentration of a medicament in after-treatment or the adjustment of the processing temperature. The whiteness of the product processed by the conventional whitening process is 125-130 under a D65 or CWF light source. Even if a whitening agent with high whiteness is adopted, the whiteness can only reach 130-135, but the whitening agent with high whiteness has high cost, poor mass production and extremely strict condition control requirements. With the expansion of the demand of people for high-end products with whiteness of more than 145, the existing products cannot meet the demand. The whiteness of the polyester fabric is improved by design and dyeing process technology, which becomes an urgent subject for technical personnel in the textile field.

Chinese published patent CN101586307A discloses a continuous high-whiteness whitening process for pure cotton fabric, comprising the following steps: padding a whitening agent solution, steaming, washing and drying, wherein the whitening agent solution is a whitening agent with medium or medium high affinity, although the product has higher whiteness and washing fastness, the method has extremely high requirements on the cleanness degree of equipment in consideration of the preparation of the equipment in production, the adjustment of the process and the matching stability in the dyeing process, and the production stability needs to be improved, so that the method is not suitable for mass production in factories.

Chinese patent publication CN1470685A discloses a physical whitening method by adding a certain amount of fluorescent whitening agent into fiber, wherein the fluorescent whitening agent can absorb ultraviolet rays with wavelength of 300-400 nm, convert the absorbed energy and radiate purple or blue fluorescence with wavelength of 400-500 nm, thus making up the absorbed blue light, improving whiteness, and giving people a pure white and bright feeling. However, by adding a fluorescent whitening agent, the fiber can only exhibit high whiteness under sunlight conditions, and the effect of high whiteness cannot be achieved indoors.

Disclosure of Invention

The invention aims to provide a polyester fiber which can realize high whiteness under the condition of no ultraviolet light.

The technical solution of the invention is as follows:

a high-whiteness polyester fiber containing inorganic particles and/or organic particles; when the fiber contains inorganic particles, the fiber simultaneously contains quaternary ammonium hydroxide shown as a formula 1,

in the formula 1, the compound is shown in the specification,

in the formula 1, R₁、R₂、R₃、R₄Are respectively a group shown in a formula 2 or a formula 3,

in the formula (2), the first and second groups,

in the formula 3, the first step is,

in the formula 2, n is an integer of 0-17, and in the formula 3, m is an integer of 0-3.

The quaternary ammonium base is preferably one or more of tetramethylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium hydroxide or tetrapropylammonium hydroxide. The content of quaternary ammonium base in the fiber is preferably 1 to 100ppm in terms of nitrogen element relative to the weight of the fiber.

The particle diameter of the inorganic particles is preferably 1.5 μm or less.

The inorganic particles are preferably at least one of titanium dioxide, calcium carbonate, barium sulfate, zinc oxide, zirconium oxide, and iron oxide, and more preferably rutile titanium dioxide.

The content of the inorganic particles is preferably 2 to 20wt% with respect to the weight of the fiber.

The particle size of the organic particles is preferably 3.0 μm or less.

The organic particles are preferably organosilicone particles.

The content of the organic particles is preferably 2 to 20wt% with respect to the weight of the fiber.

The high-whiteness polyester fiber of the present invention is preferably a core-sheath type composite fiber in which the core component is a polyester containing inorganic particles and the sheath component is a polyester containing organic particles.

The mass ratio of the core component to the sheath component in the core-sheath composite fiber is preferably 20:80 to 80: 20.

The high-whiteness polyester fiber provided by the invention has a higher whiteness WI value under the condition of no ultraviolet light, and has the advantages of less filtration pressure rise in the spinning processing stage, long service life of components and low cost.

Detailed Description

One of the technical schemes disclosed by the invention is that the high-whiteness polyester fiber contains inorganic particles and quaternary ammonium hydroxide shown as a formula 1.

The inorganic particles have a high refractive index and a large surface reflection, and can improve the whiteness of the polyester fiber.

The inorganic particles are preferably at least one of titanium dioxide, calcium carbonate, barium sulfate, zinc oxide, zirconium oxide, and iron oxide, and among them, titanium dioxide is more preferred. Compared with other types of titanium dioxide, such as anatase titanium dioxide, rutile titanium dioxide has a higher refractive index, white light reflected by the surface is more, and the whiteness is higher. And the rutile type titanium dioxide has higher absorption in the ultraviolet 380-425 nm region, reflects stronger blue light in the wavelength range of the blue region, and can also present higher whiteness. Therefore, rutile titanium dioxide is most preferable as the inorganic particles according to the present invention.

The particle diameter of the inorganic particles is preferably 1.5 μm or less. When the particle size of the inorganic particles is too large, the inorganic particles easily block a filter screen in a spinning assembly in the spinning process, so that the pressure of the assembly is quickly increased and exceeds the usable upper limit of the pressure of the assembly in a short time, and the machine must be stopped, thereby influencing the productivity; meanwhile, broken filaments and floating filaments are increased in the spinning process, and the spinning operability and the basic physical properties of the fibers are influenced. The particle size of the inorganic particles of the present invention is more preferably 1.0 μm or less.

The content of the inorganic particles is preferably 2 to 20wt% with respect to the weight of the fiber. When the content of the inorganic particles is too low, there is no effect of improving the whiteness of the polyester fiber at all; when the content of the inorganic particles is too high, the possibility of falling off of the inorganic particles due to exposure of the inorganic particles on the surface is increased, and in addition, the inorganic particles generally have a large hardness, and the parts are easily damaged by friction between the spinning process and a yarn guide of a spinning machine or the like. The content of the inorganic particles of the present invention is more preferably 2 to 15wt% based on the weight of the fiber.

Generally, inorganic particles have negative charges on their surfaces, and the negative charges on the surfaces of the inorganic particles are neutralized in an acidic system, so that the inorganic particles aggregate during polymerization. The addition of the basic substance can neutralize the acidity of the polymerization system, thereby achieving the effect of inhibiting the aggregation of the inorganic particles. However, in the prior art, metal acetate alkaline substances are often added, and the introduction of the metal acetate alkaline substances can cause the increase of foreign matters in the polyester, so that the filtration pressure in the subsequent processing process is increased. In the high-whiteness polyester fiber, the quaternary ammonium hydroxide with strong basicity is used, and the completely dissociated hydroxyl groups can neutralize acid components in a polymerization system, so that the effect of inhibiting the aggregation of inorganic particles is achieved. And because the quaternary ammonium base does not contain metal components, the problem of filtration pressure rise cannot be caused in the subsequent processing process.

The quaternary ammonium base has a structural formula shown in formula 1:

in the formula 1, the compound is shown in the specification,

in the formula 1, R₁、R₂、R₃、R₄Are respectively a group shown in a formula 2 or a formula 3,

in the formula (2), the first and second groups,

in the formula 3, the first step is,

in the formula 2, n is an integer of 0-17, and in the formula 3, m is an integer of 0-3.

The quaternary ammonium base is preferably one or more of tetramethylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium hydroxide or tetrapropylammonium hydroxide.

The content of the quaternary ammonium hydroxide in the high-whiteness polyester fiber is preferably 1 to 100ppm in terms of nitrogen element relative to the weight of the fiber. When the quaternary ammonium base content is too low, the effect of inhibiting the aggregation of the inorganic particles is not exerted; when the quaternary ammonium base content is too high, the color tone of the polyester may be deteriorated.

The second technical scheme disclosed by the invention is that the high-whiteness polyester fiber contains organic particles.

The organic particles have a circular structure, are monodispersed in the polyester, and do not aggregate. And the organic particles have a light diffusion effect, so that the reflection of light can be increased, and the whiteness of the polyester fiber can be improved.

The organic particles may be acrylic particles, polyurethane particles, polystyrene particles, or organosilicone particles, and among them, organosilicone is preferable.

The particle size of the organic particles is preferably 3.0 μm or less. When the particle size of the organic particles is too large, the organic particles easily block a filter screen in a spinning assembly in the spinning process, so that the pressure of the assembly quickly rises and exceeds the usable upper limit of the pressure of the assembly within a short time, and the assembly must be stopped, thereby affecting the productivity.

The content of the organic particles is preferably 2 to 20wt% based on the weight of the polyester fiber. When the content of the organic particles in the polyester fiber is too low, the whiteness improvement of the polyester fiber is not effective; when the content of organic particles in the polyester fiber is too high, the whiteness of the polyester fiber reaches balance, and the filtration pressure rise in the spinning process is obvious.

The third technical scheme disclosed by the invention is that the high-whiteness polyester fiber simultaneously contains inorganic particles and organic particles and contains quaternary ammonium hydroxide shown as a formula 1.

In order to achieve higher whiteness, the inorganic particles and the organic particles may be used in combination in the present invention. When the organic particles are used in combination with the inorganic particles, the organic particles have an additive effect on the whiteness of the polyester fibers, and the organic particles have a light diffusing effect, so that the diffuse reflection effect of the inorganic particles can be enhanced to achieve higher whiteness.

The high-whiteness polyester fiber of the present invention may be present in various forms known in the art, such as a single fiber, a sea-island fiber, a core-sheath fiber, a side-by-side fiber, a long fiber, a short fiber, etc. In the present invention, the form of the high-whiteness polyester fiber is preferably a core-sheath fiber, and more preferably, the core component of the core-sheath composite fiber is a polyester containing inorganic particles, and the sheath component is a polyester containing organic particles. The inorganic particles of the core component have a refractive index higher than that of the polyester, and the organic particles of the sheath component have a refractive index lower than that of the polyester, so that when light is irradiated onto the surface of the polyester fiber, the sheath component having a low refractive index easily enters the core-sheath interface, and the internal reflection is increased due to the high refractive index of the core portion, whereby the overall whiteness of the polyester fiber is improved.

The mass ratio of the core component to the sheath component in the core-sheath fiber is preferably 20: 80-80: 20. If the core component is too small, the whiteness of the polyester fiber is not significantly increased; if the sheath component is too small, the sheath component is not thick enough to completely cover the core component, resulting in exposure of the inorganic particles, damage to spinning equipment during high-speed spinning, and the exposed inorganic particles easily fall off, thereby affecting the properties of the core-sheath composite fiber. In the core-sheath fiber, the content of the inorganic particles is 2 to 20wt% relative to the core component, and the content of the organic particles is 2 to 20wt% relative to the sheath component.

The high-whiteness polyester fiber of the present invention can be produced by a known method. For example, when the high-whiteness polyester fiber of the present invention is a core-sheath fiber, the preparation method thereof can be exemplified by the following:

(1) uniformly mixing terephthalic acid, ethylene glycol, propylene glycol or butanediol, putting into a reaction kettle, carrying out esterification reaction at a certain temperature, adding a certain proportion of ethylene glycol solution of titanium dioxide after the esterification is finished, and adding ethylene glycol;

(2) transferring the reaction product into a polycondensation kettle, adding a titanium compound or an antimony compound as a catalyst, preferably selecting an ethylene glycol antimony catalyst, adding a heat stabilizer, a toner and the like, adding the rest part of titanium dioxide and optionally adding silicone particles, carrying out polycondensation reaction at 280 ℃, and discharging and granulating the polymer after the polymer reaches the required viscosity to obtain high-whiteness polyester;

(3) or (1) adding silicone particles directly in the step (2) without adding titanium dioxide particles, and carrying out polymerization reaction, then discharging and granulating to obtain high-whiteness polyester;

(4) respectively carrying out melt spinning on the polyester obtained in the step (2) or the polyester obtained in the step (3) at 280 ℃ to obtain polyester fibers;

(5) the obtained polyester containing titanium dioxide particles is used as a core component, and the polyester containing silicone particles is used as a sheath component, and the core-sheath composite spinning and false twisting are carried out to obtain the high-whiteness polyester fiber.

The whiteness WI of the polyester fiber of the invention is more than 80.

The preparation method of the high-whiteness polyester fiber is simple, the filtration pressure rise is little in the spinning processing stage, the service life of the component is long, and the cost is low. The polyester fiber has high whiteness, the whiteness WI value can reach more than 80, and the high whiteness effect can be realized when no ultraviolet light is irradiated.

The physical property parameters in the examples were measured by the following methods.

(1) Whiteness WI value

The fiber obtained after spinning was woven into a tubular knitted article, and the measurement was performed using a colorimeter (Data color) under the condition of a wavelength of 400 to 780 nm.

(2) Filtration pressure difference delta Pa during spinning

Spinning was carried out using a hammer spinning machine. Under the condition of a certain discharge quantity, the core-sheath polyester respectively passes through a filter screen, the aperture of the filter screen is 15 mu m, the spinning temperature is the melting point of the polyester + 25 ℃, the total discharge quantity of the core-sheath is 25.2g/min, the discharge quantity of the core-sheath component is respectively calculated according to the core-sheath proportion in the embodiment, the pressure before the filter screen is recorded as initial pressure Pa1 at 30min after the feeding is started, the final pressure at the spinning end is recorded as Pa2, and the filter pressure rise value delta Pa is (Pa 2-Pa 1)/spinning time. The smaller Δ Pa means that the foreign matter in the polyester is smaller and the spinning is more stable. The single component spinning is characterized by the difference between the final pressure at the end of the spinning and the initial pressure.

(3) Measurement of N element content

Weighing 15-20 mg of sample, placing the sample in oxygen flow for combustion, fully oxidizing organic components of the sample by using an oxidant, quantitatively converting N element into volatile oxides corresponding to the N element, enabling the products to flow through silica gel packed column chromatography, respectively measuring the concentrations of the products by using a thermal conductivity cell detector, and finally determining the content of the N element by using an external standard method.

(4) Inorganic particle content in fiber

About 4g of the fiber is taken, melted and prepared into a sample, the content of metal elements in the fiber is measured by an X-ray fluorescence spectrometer (manufacturer: Rigaku, model: ZSX Primus III +), and then the content of inorganic particles in the fabric is calculated by molecular formula.

(5) Content of organic particles in fiber

When the fiber contains both inorganic particles and organic particles, firstly, the content of the inorganic particles in the fiber is measured by the method (4), then, the fiber is burnt, an ash value is obtained after the fiber is burnt by an ash tester, and the content of the inorganic particles measured by the method (4) is subtracted, so that the content of the organic particles in the fiber is obtained through conversion.

When the fiber only contains organic particles, the fiber is directly combusted, an ash content value is obtained after the combustion by an ash content tester, and the content of the organic particles in the fiber is obtained through conversion.

(6) Average particle diameter of inorganic particles and organic particles

The cross-sectional photograph of the fiber was taken by SEM, 10 particles were selected after printing, the diameter through the center of the particles was measured, and the final result was the average of 10 sets of data.

(7) Cross-sectional ratio of core component to sheath component in fiber

The cross section of the composite fiber was photographed by SEM, a photograph of the cross section was printed on paper, and the area S of the cross section of the core component was obtained by an area meter₁Sheath component cross-sectional area S₂Core component ratio of S₁/（S₁＋S₂）。

(8) Rutile titanium dioxide

The obtained fiber is melted to prepare a film, an X-ray diffraction device is used for testing the position of a crystallization peak, the position of a crystallization peak of common rutile titanium dioxide is tested at the same time, and the crystal form of the titanium dioxide is judged by comparing the positions of the crystallization peaks obtained by the X-ray diffraction device and the rutile titanium dioxide.

The present invention will be described in more detail by way of examples.

Example 1

Adding 82 parts by weight of terephthalic acid and 35.3 parts by weight of ethylene glycol into an esterification kettle for esterification reaction, carrying out esterification reaction at 240 ℃, judging that the reaction is finished after the water yield reaches the theoretical amount, adding 26 parts by weight of ethylene glycol, stirring for 30 minutes, and then moving to a polymerization kettle. 0.04 part by weight of ethylene glycol antimony, 0.02 part by weight of phosphoric acid, and 2 parts by weight (amount of titanium dioxide) of a titanium dioxide ethylene glycol solution prepared with tetraethylammonium hydroxide, wherein the content of tetraethylammonium hydroxide in the ethylene glycol solution of titanium dioxide was 1000ppm, and the reaction was carried out at 280 ℃ under high vacuum to a desired viscosity and then discharged. The obtained polymer is spun and false twisted to prepare the high-whiteness polyester fiber. The whiteness WI of the polyester fiber obtained was 85.

Example 2

After the esterification reaction, 3 parts by weight (titanium dioxide amount) of a titanium dioxide glycol solution prepared with tetraethylammonium hydroxide was added, and the remainder was the same as in example 1.

Example 3

The same procedure as in example 1 was repeated except that 8 parts by weight (amount of titanium dioxide) of a titanium dioxide glycol solution prepared with tetraethylammonium hydroxide was added after the completion of the esterification reaction.

Example 4

After the completion of the esterification reaction, 13 parts by weight (amount of titanium dioxide) of a titanium dioxide glycol solution prepared with tetraethylammonium hydroxide was added, and the same procedure as in example 1 was repeated.

Example 5

The same procedure as in example 1 was repeated except that 18 parts by weight (amount of titanium dioxide) of a titanium dioxide glycol solution prepared with tetraethylammonium hydroxide was added after the completion of the esterification reaction.

Example 6

The procedure of example 5 was repeated except that the titanium dioxide/ethylene glycol solution was prepared so that the tetraethylammonium hydroxide content was 5000 ppm.

Example 7

Adding 82 parts by weight of terephthalic acid and 35.3 parts by weight of ethylene glycol into an esterification kettle for esterification reaction, carrying out esterification reaction at 240 ℃, judging that the reaction is finished after the water yield reaches the theoretical amount, adding 26 parts by weight of ethylene glycol, stirring for 30 minutes, and then moving to a polymerization kettle. 0.04 parts by weight of ethylene glycol antimony, 0.02 parts by weight of phosphoric acid, and 2 parts by weight (in terms of the amount of silicone) of an organosilicone ethylene glycol solution were added, and the mixture was reacted at 280 ℃ under a high vacuum condition to obtain a desired viscosity, and then discharged. The obtained polymer is spun and false twisted to prepare the high-whiteness polyester fiber. The whiteness WI of the resulting polyester fiber was 82.

Example 8

After the esterification was completed, 3 parts by weight (amount of silicone) of the silicone glycol solution was added, as in example 7.

Example 9

After the esterification was completed, 8 parts by weight (amount of silicone) of the silicone glycol solution was added, as in example 7.

Example 10

After the esterification was completed, 13 parts by weight (amount of silicone) of the silicone glycol solution was added, as in example 7.

Example 11

After the esterification was completed, 18 parts by weight (amount of silicone) of the silicone glycol solution was added, as in example 7.

Example 12

After the esterification was completed, 3 parts by weight (amount of titanium dioxide) of a titanium dioxide glycol solution prepared with tetraethylammonium hydroxide and 5 parts by weight (amount of silicone) of an organosilicone glycol solution were added, as in example 2.

Example 13

After the esterification was completed, 8 parts by weight (amount of titanium dioxide) of a titanium dioxide glycol solution prepared with tetraethylammonium hydroxide and 10 parts by weight (amount of silicone) of an organosilicone glycol solution were added, as in example 2.

Example 14

The procedure of example 13 was repeated except that the titanium dioxide/ethylene glycol solution was prepared so that the tetraethylammonium hydroxide content was 5000 ppm.

Example 15

Anatase titanium dioxide was used as in example 5.

Example 16

1 part by weight of rutile titanium dioxide was added before polymerization, and the same procedure as in example 1 was repeated.

Example 17

The rutile titanium dioxide was added at 28 weight percent during the esterification stage as in example 1.

Example 18

The procedure of example 3 was repeated except that the content of tetraethylammonium hydroxide in the titanium dioxide/ethylene glycol solution was 6500 ppm.

Example 19

1 part by weight of an organic silicone was added before polymerization, as in example 7.

Example 20

Example 7 was repeated except that 28 parts by weight of an organic silicone was added after the esterification reaction and 2 parts by weight of an organic silicone was added before the polymerization.

Example 21

The quaternary ammonium base used to prepare the titanium dioxide was tetrapropylammonium hydroxide, as in example 13.

Example 22

The polyester obtained in the same manner as in example 2 was used as a core component, the polyester obtained in the same manner as in example 8 was used as a sheath component, and the ratio of the core to the sheath was 20:80 to carry out core-sheath composite spinning and false twisting to obtain the high-whiteness polyester fiber. The whiteness WI of the resulting polyester fiber was 112.

Example 23

The polyester obtained in the same manner as in example 5 was used as a core component, the polyester obtained in the same manner as in example 11 was used as a sheath component, and the ratio of the core to the sheath was 20:80 to carry out core-sheath composite spinning and false twisting to obtain the high-whiteness polyester fiber.

Example 24

The core-sheath composite ratio is 40: 60 as in example 23.

Example 25

The core-sheath composite ratio is 60: 40 as in example 23.

Example 26

The core-sheath composite ratio is 80:20 as in example 23.

Example 27

The same procedure as in example 6 was repeated except that the polyester obtained was used as a core component in example 26.

Example 28

The core-sheath ratio is 10: 90 as in example 22.

Example 29

The same as example 26 was repeated except that 28 parts by weight of rutile type titanium dioxide was added to the esterification stage of the core portion polyester and 28 parts by weight of organosilicone particles were added to the esterification stage of the sheath portion polyester.

Example 30

The core-sheath ratio is 90: 10 as in example 23.

Example 31

The core-sheath ratio is 10: 90 as in example 23.

Example 32

The quaternary ammonium hydroxide for preparing titanium dioxide is a mixed solution of tetrapropylammonium hydroxide and tetraethylammonium hydroxide, and the mass ratio of the tetrapropylammonium hydroxide to the tetraethylammonium hydroxide is 1: 1 as in example 26.

Example 33

As the inorganic particles, nano barium sulfate was used, and the rest was the same as in example 26.

Comparative example 1

The procedure of example 5 was repeated except that no quaternary ammonium hydroxide was added to prepare titanium dioxide. Because of no dispersion of quaternary ammonium base, titanium dioxide is agglomerated in the fiber, and the average particle size is large, resulting in large spinning filtration pressure.

Comparative example 2

The procedure of example 5 was repeated except that sodium hydroxide was added in an amount equimolar to that of Na element in preparing titanium dioxide. The addition of other types of alkaline compounds has a certain effect on the dispersion of titanium dioxide, but sodium hydroxide itself also constitutes foreign matter, resulting in a large spinning filtration pressure.

Comparative example 3

The procedure of example 24 was repeated except that no quaternary ammonium hydroxide was added to prepare titanium dioxide. The addition of other types of alkaline compounds has a certain effect on the dispersion of titanium dioxide, but sodium hydroxide itself also constitutes foreign matter, resulting in a large spinning filtration pressure.

Comparative example 4

The same procedure as in example 24 was repeated except that sodium hydroxide containing Na element in an amount equimolar to N element was added to prepare titanium dioxide. The addition of other types of alkaline compounds has a certain effect on the dispersion of titanium dioxide, but sodium hydroxide itself also constitutes foreign matter, resulting in a large spinning filtration pressure.