GB2303375A

GB2303375A - Far I.R.-radiating polyester fibres

Info

Publication number: GB2303375A
Application number: GB9601245A
Authority: GB
Inventors: Dae Woo Ihm; Chang Hee Lee; Jeong Yul Kim; Ji Sook Cho
Original assignee: Cheil Synthetics Inc
Current assignee: Toray Chemical Korea Inc
Priority date: 1995-07-14
Filing date: 1996-01-22
Publication date: 1997-02-19
Anticipated expiration: 2016-01-22
Also published as: DE19606266A1; DE19606266C2; KR970006375A; CN1140770A; GB9601245D0; KR0155608B1; GB2303375B

Description

is 2303375 METHOD FOR MANUFACTURING FAR INFRARED-RADIATING POLYESTER

FIBERS

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a method for manufacturing polyester fibers exhibiting a superior heat accumulating ef f ect and superior warmth retaining ef f ect upon being radiated by the sun's ray, and more particularly to a method for manufacturing polyester fibers, based on dimethylterephtalic acid and ethylene glycol, exhibiting an improved whiteness and a soft versus rough touch as well as a superior, permanent heat accumulating and warmth retaining effect, and being capable of radiating far infrared rays. The polyester fibers are manufactured by uniformly blending, in polymer, ceramic particles having a spectroscopic ref lectivity of not less than 65% in the far infrared radiating range (wavelength of 4 to 25pm).

Description of the Prior Art

Ceramic particles absorb visible and near infrared rays, exhibiting a superior thermal efficiency, from the sun's ray, convert the absorbed rays into far infrared rays, and then radiate the far infrared rays. When the radiated far infrared rays have a frequency approximately equal to that of the intrinsic vibration system established in the ceramic particles, a resonance phenomenon occurs such that the vibration system's amplitude increases. By virtue of such a resonance phenomenon, thermal energy is generated from the ceramic particle. In the case of a f iber blended with such ceramic particles, thermal energy serves to increase the temperature of the f iber. Ceramic particles also have a function of reflecting far infrared rays of 8 to 10pm emitted from the human body, thereby retaining the body heat. In this regard, filaments and staple fibers are used for sports garments, casual garments and as padding for non-woven fabrics.

Conventionally, heat-accumulating and warmth-retaining fibers blended with zirconium carbide particle have been practically used. Such fibers are disclosed in European Patent No. 302141 A. However, it is difficult to apply the fibers to an application requiring the whiteness and an application requiring dyeing.

undesirably have a deep gray color.

This is why the fibers In order to improve the whiteness in such f ibers, use of a coloration modifying agent has also been proposed. For example, the manufacturing method for a fiber using a conjugated spinning has been known, wherein a colorant is blended in the core of the f iber. Another method, which -2 is involves an addition of white pigment such as titanium oxide in a large quantity, is also known. Where these methods are used to manufacture heat- accumulating and warmth-retaining fibers blended with zirconium carbide particle, however, they involve a degradation in the heat- accumul at ing and warmthretaining effect while insufficiently improving the whiteness. In the Japanese Patent Laid-open Publication No. Heisei 3-69675, the method for manufacturing staple fibers of 6 deniers using ceramic particles is disclosed. In this method, particles of ceramic such as zirconium oxide, silicon oxide or aluminum oxide are mixed with polyester at a ratio that the total particle content is 40 wt% in accordance with a master batch process, thereby forming a chip. Together with a regular polyester chip, the chip is blend-spinned to manufacture a staple fiber of 6 deniers. In accordance with this method, a good whiteness can be obtained. However, the dispersion of particles in the fiber is poor because the amount of blended ceramic particles is large. Furthermore, the fiber touch is very rough because the blended particle has a high hardness. As a result, it is difficult to use fibers of this method for garments.

As a result of our steady research to solve the above mentioned problems, we found that fibers exhibiting an improved whiteness and a soft touch as well as a superior, permanent heat accumulating and warmth retaining effect upon being radiated by the sun's ray could be manufactured by adding far infrared-radiating ceramic particles to the fiber material. On the basis of this fact, the present invention has been made.

is SUMMARY OF THE INVENTION

Therefore, an object of the invention is to provide a method for manufacturing fibers exhibiting an improved whiteness and a soft versus rough touch as well as a superior, permanent heat accumulating and warmth retaining effect upon being radiated by the sun's ray.

In accordance with the present invention, this object is accomplished by providing a method for manufacturing far infrared-radiating fibers made of a polyester primarily comprising dimetbylterephtalic acid and ethylene glycol, characterized by adding, to the polyester, at least two kinds of mixed, far infrared-radiating ceramic particles having a spectroscopic reflectivity of not less than 65% in a far infrared radiating wavelength range of 4 to 25pm.

The far infrared-radiating ceramic particles are selected from a group consisting of ZrO2, ZrSiO4, S'02 and T'02 all having a grain size distribution of 0.001 to 1.0pm and an average grain size of not more than 0.02pm.

DETAILED DESCRIPTION OF THE INVENTION

In the production of a polyester for fibers using a polycondensation between dimetbylterephtalic acid and ethylene glycol, it is required to provide a sophisticated technique for uniformly blending, in polymer, ceramic particles having a spectroscopic reflectivity of not less than 65% in the far infrared radiating range (wavelength of 4 to 25pm).

The far infrared-radiating ceramic particle conventionally used includes Zr02, A1203, BaS04, S'02, T'021 MnO2, Fe203, CoO, Cuo, ZrC, MgO, Cr203, ZrS'04, K20, SiC, ZrN and the like. They have different chemical and physical properties as well as different far infrared radiating ranges. After a number of comparative tests, the inventors found that Zr02, S'021 T'02 and ZrSiO4 were preferable in the implementation of the present invention. Zr02 and T'02 exhibit superior far infrared radiation characteristic and provide good fiber color, namely, a good whiteness. On the other hand, S'02 and ZrS'04 exhibit an ultraviolet shielding effect as well as a superior far infrared radiation characteristic.

Preferably, the ceramic particle used in accordance with the present invention has a grain-size distribii'tion of 0.001 to I.Opm and an average grain size of not more than 0.02pm. It is important that the ceramic particle should not involve any aggregation in the process of forming a slurry using ethylene glycol and in the process of being blended in a polymer. Where the grain-size distribution of the ceramic particle is less than 0.001pm, there is a possibility that the aggregation occurs easily. On the other hand, ceramic particles having a grain-size distribution of more than 1. Opm provides an undesirable fiber touch and a poor fiber workability.

In order to obtain an improved dispersion of ceramic particles, a slurry is produced which contains ethylene glycol, as a solvent, in an amount of not less than 80% and ceramic particles in an amount of 10.0 to 20.Owt%. At the slurry forming step, the mixture of ceramic particle with the solvent is stirred at a speed of not less than 2,500 RPM. In order to filter grains having a large size and foreign matters, filters of 2pm, 5pm and 10pm are disposed among moving vessels, respectively.

The slurry, namely, the ceramic particle solution, in which ceramic particles are completely dispersed, is then fed to a reaction tube via a feeding tube to disperse the ceramic particles in a polymer. During the feeding, ceramic particles may be deposited in the feeding tube in accordance with the shape and length of the feeding,tube. In this c9nnection, the feeding tube is constructed to have a straight shape if possible, to allow the solution to flow downwards, and to have a length of not more than 10m in accordance with the present invention.

The content of ceramic particles blended in the polymer is is preferred to be 1.0 to 6.Owt%, taking into consideration the heat accumulating and warmth retaining effect and the f iber touch. The ceramic particles to be blended in the polymer are added in the form of a mixture which comprises Zr02 + Ti02, Zr02 + TiO2 + S'02, and ZrS'04 + T'02- The mixing ratio of components in the mixture is also important in terms of the dispersion of ceramic particle in the polymer, the fiber workability, the fiber temperature increasing effect, and the fiber touch. Zr02 is preferred to have a content of 30 to 70%. ZrS'04 is preferred to have a content of 30 to 70%. Preferably, S'02 has a content of 25 to 45%. It is also preferred that T'02 has a content of 25 to 45%.

The ceramic particle slurry, which consists of at least two kinds of ceramic particles and ethylene glycol, can be added to either an ester exchanging reaction tube or a polymerizing reaction tube. However, it is advantageous in terms of preventing particle aggregation that the addition of the slurry is carried out at a low temperature if possible, taking into consideration the. physical characteristic of ceramic particles. In accordance with the presext. invention, the addition of the ceramic particle slurry is carried out when the reaction tube is at a temperature of about 155 to 200C after completing an elution of methanol in the ester exchanging reaction. The addition time is also appropriately limited in order to prevent any problem from occurring in the reaction tube due to an excess additio n of ethylene glycol. It is preferred that the addition time be 10 to 15 minutes. Thus, a polyester exhibiting a greater ceramic particle dispersion and an improved whiteness is produced in accordance with the present invention.

The present invention will be understood more readily with reference to the following examples and comparative examples; however these examples are intended to illustrate the invention and are not to be construed to limit the scope Of the present invention.

Example 1

To produce polyester by condensation between dimethylterephtalic acid and ethylene glycol, two kinds of far infrared-radiating ceramic particles, namely, Zr02 particle and T'02 particle were prepared and then mixed together at a ratio of 58: 42. The ceramic particle mixture was then mixed with ethylene glycol, thereby producing the slurry having a ceramic particle in a weight ratio of 18wt%. The slurry was formed by continuously stirring the resultant mi-xture using a stirrer at a high speed of not less than 2,500 RPM for about two hours. By this stirring, the ceramic particles were uniformly dispersed in the slurry.

The Zr02 and TiO2 particles have a grain-size distribution of 0.001 to 0. 6pm. The ceramic particle slurry was then added is to the polyester prepared above such that the content of the ceramic particles was 4.5% based on the weight of the polymer. The addition of the ceramic particle slurry was carried out at a low rate when the reaction tube was at a temperature of 175C after completing an elution of methanol by an ester exchanging reaction. The addition of the ceramic particle slurry was continued for about 15 minutes. As a catalyst for the ester exchanging reaction, 50Oppm Mn(OAc)2 and 30Oppm Sb203 were also added in the reaction tube. For this ester exchanging reaction, the reaction completion tempera-Lure was 290C. Also, the reaction time was about 3 hours and 10 minutes. Thus, polyester chips were manufactured.

Polyester chips were then dried to have a moisture content of not more than 40ppm. From the dried polyester chips, an undrawn yarn was spinned at a spinning temperature of 270 t o 285C at a spinning speed of 1, 850m/min. Thereafter, the spinned yarn was drawn at a draw ratio of about 2.7, thereby manufacturing a FY75/36 filament having a fineness of 75 deniers. Using this filament, a ski suit was made. Physical properties of the fiber raw material and final f iber product were evaluated. For the f iber raw material, the dispersion (blending degree) of ceramic particles in the polymer was evaluated. For the final product, namely, the ski suit, the fabric touch and the heat accumulating and warmth retaining effect were evaluated. The evaluation of the 1.5 dispersion of ceramic particles in the polymer was carried out by observing a plasma-treated sample magnified by several thousand magnifications through an electron microscope. Spinning and drawing workabilities were also evaluated, based on data about processing works. The fiber whiteness was evaluated through an observation with the naked eye or by using a color matching machine. The heat accumulating and warmth retaining effect was evaluated using a thermal image measuring appliance. The fabric touch was evaluated in terms of wear and softness. The evaluation results were described in Table 1.

Using the polyester chip, an 1.2 denier x 38mm raw cotton was manufactured as a staple f iber. This staple f iber is woven to manufacture a T 100 woven fabric for jackets. After making a coat using the woven fabric, its physical properties were evaluated. The evaluation was carried out in the same manner as f or the ski suit. The evaluation results were described in Table 1.

Example 2

Using two kinds of far infrared-radiating ceramic particles, namely, ZrSi04 particle and T'02 particle mixed together in a ratio of 58: 42, a slurry was produced in the same manner as in Example 1. In this case, the ceramic particles were blended in ethylene glycol in a concentration of 18wt%. Concerning the ZrS'04 and T'02 particles, those having a grain-size distribution of 0.01 tO 1.Opm were used.

Example 3

Using three kinds of far infrared-radiating ceramic particles, namely, Zr02 particle, T'02 particle and S'02 particle mixed together in a ratio of 30: 40: 30, a slurry was produced in the same manner as in Example 1. In this case, the ceramic particles were blended in ethylene glycol in a concentration of 18wt%. Concerning the Zr02 and T'02 particles, those having a grain-size distribution of 0.005 to 1.Opm were used.

Comparative Example 1 Using two kinds of far infrared-radiating ceramic particles, namely, Zr02 particle and T'02 particle mixed together in a ratio of 50: 50, a slurry was produced in the same manner as in Example 1. The ceramic particle slurry was then added to a polymer contained in a reaction tube such that the content of the ceramic particles was 7.3wt% based on the weight of the polymer. The addition of the ceramic particle slurry was carried out at a low rate when the reaction tube was at the temperature of 232C just before an initial polymerization for an ester exchanging reaction started. The addition of the ceramic particle slurry was continued for about 15 minutes.

Comparative Example 2 Using two kinds of far infrared-radiating ceramic particles, namely, ZrSiO4 particle and T'C)2 particle mixed together in a ratio of 70: 30, a slurry was produced in the same manner as in Example 2. The ceramic particle slurry was then added to a polymer contained in a reaction tube such that the content of the ceramic particles was 7.3wt% based on the weight of the polymer. The addition of the ceramic particle slurry was carried out at a low rate when the reaction tube was at the temperature of 232C just before an initial polymerization for an ester exchanging reaction started. The addition of the ceramic particle slurry was continued for about 15 minutes.

Comparative Example 3 Using three kinds of far infrared-radiating ceramic particles, namely, ZrO2 particle, Ti02 particle and S'02 mixed together in a ratio of 30: 50:, 20, a slurry was produced in the same manner as in Example 1. The ceramic particle slurry was then added to a polymer contained in a reaction tube such that the content of the ceramic particles was 7.3wt% based on the weight of the polymer. The addition of the ceramic particle slurry was carried out at a low rate when the reaction tube was at a temperature of 232C just before an initial polymerization for an ester exchanging reaction started. The addition of the ceramic particle slurry was continued for about 15 minutes.

TABLE I

Ceramic Particle Mixing Grai Ratio Content sizeP) Sample D2) W3 T4) Out6) Evaluation Result Therma Effect In7) Ski 6C 8C ZrO2: 58% 0.001- Suit 0 0 @ I I Ex. 1 Ti02: 42% 4. 5wt% 0. 61im 9) VC 7C Coat 6 0 0 1 1 ZrSi0j: 58% Ex.2 TiO,:4;2% 4.5wt% 1.0pm Ski 0.01- Suit Coat 4'C 0 0 X 1 C T 0 0 X 4'C 4.5C 1 1 Ski 3C 4C ZrC)2: 30% 0. 005- Suit o 0 0 1 1 Ex.3 Ti02:40% 4. 5wt% 1. Opm S'02: 30% VC VC Coat 0 0 0 1 1 Ski Z r02: 5 0 9o 0.001- Suit 0 X X Com.1 T'02:50% 7.3wt% 0. 6lim Coat 0 X X Ski ZrS'04: 70% 0.001- suit Com.2 Tio,:30% 7.3wt% 1.Opm L X X X Coat X X X gki Zr02: 30% 0. 005- Suit X X X Com.3 T'02:50% 7. 3wt% 1. Opm S i04: 20% Coat X X X 14- Grain sizel) Grain-size Distribution D2) Dispersion of particle W3) Spinning and Drawing Workability T4) Fiber Touch Thermal Effect5) Heat Accumulating and Warmth Keeping Effect Out6) Outside of Suit In7) Inside of Suit Ski Suit8) Filament Ski Suit Coat9) Fiber Coat The heat accumulating and warmth retaining effect exhibited in suits of Example 1 to 3 are evaluated in terms of the increased suit temperature, as compared to those made of routine raw yarns or raw cottons.

9: good, 0: medium, x: bad

Claims

CLAIMS:

1. A method for manufacturing far infraredradiating polyester fibres wherein there is introduced into the polyester a mixture of at least two kinds of far infrared-radiating ceramic particles each having a spectroscopic reflectivity of not less than 65% in the far infrared radiating range of 4 to 25gm.

2. A method according to claim 1, wherein the far infrared-radiating ceramic particles are selected from Zr02. ZrS'04, S'02 and T'02.

3. A method according to claim 2, wherein the far infrared-radiating ceramic particles comprise Zr02 and T'02

4. A method according to claim 2, wherein the far infrared-radiating ceramic particles comprise Zro., S'02 and T'02.

5. A method according to claim 2, wherein the far infraredradiating ceramic particles are selected f rom ZrSiO, and T'02 20

6. A method according to any preceding claim, wherein the ceramic particles have a particle size distribution of 0.001 to 1.Ogm and an average particle size of 0.02gm.

7. A method according to any preceding claim, wherein the far infrared-radiating ceramic particles are introduced into the polyester in an amount sufficient to provide no more than 6.Owt% of the particles, based on the weight of the polyester.

8. A method according to any preceding claim, wherein the far infrared-radiating ceramic particles are introduced into the polyester in an amount sufficient to provide at least 1.Owt% of the particles, based on the weight of the polyester.

9. A method according to any preceding claim, wherein the ceramic particles are introduced into the polyester in the form of a ethylene glycol slurry of the particles.

10. A method according to claim 9, wherein the ceramic particle slurry is introduced into the polyester via the ester exchanging reaction tube or the polymerizing reaction tube.

11. A method according to claim 10, wherein the temperature of the reaction tube is from 155 to 2000C.

12. A method according to any preceding claim, wherein the polyester is primarily one made from the polymerization of dimethylterephthalic acid and ethylene glycol.

13. Polyester fibres incorporating a mixture of at least two kinds of far infrared-radiating ceramic particles each having a spectroscopic reflectivity of not less than 65k in the far infrared radiating range of 4 to 25tm.

14. Polyester fibres according to claim 13, wherein the far infrared-radiating ceramic particles are selected f rom Zr02, ZrS'04, SiO. and T'02.

15. Polyester fibres according to claim 14, wherein the far infrared-radiating ceramic Particles comprise ZrO2 and T'02

16. Polyester fibres according to claim 14, wherein the far infrared-radiating ceramic particles comprise Zr02, S'02 and T'02'

17. Polyester fibres according to claim 14, wherein the far infrared-radiating ceramic particles are selected f rom ZrS'04 and T'02'

18. Polyester fibres according to any one of claims 13 to 17, wherein the ceramic particles have a particle size distribution of 0.001 to 1-Ogm and an average particle size of 0.02Am.

19. Polyester fibres according to any one of claims 13 to 18, wherein the far infrared-radiating ceramic particles are introducedinto the polyester in an amount sufficient to provide no more than 6.Owtk of the particles, based on the weight of the polyester.

20. Polyester fibres according to any one of claims 13 to 19, wherein the far infrared-radiating ceramic particles are introduced into the polyester in an amount sufficient to provide at least 1.Owt% of the particles, based on the weight of the polyester.

21. A fabric woven from a polyester fibre made by a method as claimed in any one of claims 1 to 12, or as claimed in any one of claims 13 to 20.

22. A garment made from the fabric of claim 21.

23. A method for manufacturing far infraredradiating polyester fibres substantially as hereinbefore described, with reference to the accompanying examples.

24. Polyester fibres substantially as hereinbefore described, with reference to the accompanying examples.