JPH09241925A - Hygroscopic polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hygroscopic polyester fiber, producible with good yarn manufacturing properties and having excellent hygroscopicity and light resistance. SOLUTION: This hygroscopic polyester fiber comprises a polyester, containing 3-50wt.% polyalkylene glycol having 2000-20000 average molecular weight in a polyalkylene terephthalate, cerium oxide and talc or cesium oxide and silica and further 0.05-10wt.% particles having the surface coated with amorphous silica and 0.1-3.0μm average particle diameter therein.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester fiber having excellent hygroscopicity.

[0002]

2. Description of the Related Art Polyesters represented by polyethylene terephthalate have excellent mechanical and chemical properties, are used in a wide range of fields, and have a very wide range of uses, especially as synthetic fibers. However, since the fiber made of such polyester is hydrophobic,
Compared with natural fibers, the hygroscopicity is remarkably inferior, and the use in fields where hygroscopicity is required is greatly restricted.

Conventionally, various attempts have been made to impart hydrophilicity or hygroscopicity to polyester fibers, but most of the attempts are made by devising the fiber shape or by post-processing. For example, in Japanese Examined Patent Publication No. 61-60188, a hollow fiber is prepared by using a polyester containing an alkyl sulfonate, and the amount of the hollow fiber is reduced by an alkali so that the fine pores are uniformly dispersed. A fiber in which a part of the above is a through hole from the surface to the hollow portion is disclosed. This fiber has some water absorbability due to the capillary phenomenon, but its hygroscopicity is limited because the polymer itself is hydrophobic.

On the other hand, there has been proposed a method of adding a hydrophilizing agent such as polyalkylene glycol or polyalkylene glycol and a sulfonic acid metal salt derivative to polyester during polymerization or spinning. However, these hydrophilizing agents,
In particular, since polyalkylene glycol has an ether bond, it has very poor light resistance and has a problem that it cannot be used.

In order to solve this problem, a composite fiber containing a polymer containing these hydrophilic agents as a core component has been proposed. However, since the polyalkylene glycol expands due to water absorption, the sheath cracks and the weight is reduced. There is a problem that the hygroscopic component is eluted. In order to prevent this sheath cracking, a hollow portion is provided inside the core-sheath structure (Japanese Patent Laid-Open No. 4-1081).
No. 13) or a three-layer structure in which a hygroscopic component is sandwiched between polyalkylene terephthalates (Japanese Patent Laid-Open No. 7-278960) has been taken, but the process control is very difficult, and the development of irregular shape, high speed, etc. There was a problem that it was difficult.

Therefore, it is strongly desired to improve the light resistance of the hygroscopic polyester itself. In order to improve the light resistance, a method of incorporating an organic light stabilizer such as a benzotriazole-based or benzophenone-based organic light-resistant agent, an inorganic light-resistant agent such as fine particle titanium oxide, fine particle zinc oxide or cerium oxide (JP-A-2-210020) into polyester is used. Proposed. However, benzotriazole-based and benzophenone-based organic light stabilizers have poor thermal stability, and few of them can withstand the polymerization temperature or spinning temperature of polyester, and there is a problem that the color tone of the polymer is significantly impaired by the addition of these. It was On the other hand, inorganic light stabilizers such as fine particles of titanium oxide and fine particles of zinc oxide have good thermal stability, but often have poor particle dispersibility, leading to rapid increase in pack pressure during spinning and frequent yarn breakage. However, the spinning operability was poor, and neither was practical.

The present inventors have previously added an inorganic light-proofing agent obtained by coating particles of cerium oxide and talc or cerium oxide and silica with amorphous silica to a flame-retardant polyester copolymerized with an organic phosphorus compound. It was found that the light resistance was improved by this (JP-A-7-258520). But,
Depending on the polymer in which this light stabilizer is also dispersed, the dispersibility is not sufficient, and it has been difficult to satisfy both the light resistance and the spinnability at the same time.

[0008]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a polyester fiber which can be produced with good spinnability and which has excellent hygroscopicity and light resistance.

[0009]

Means for Solving the Problems The present invention is to solve the above-mentioned problems, and its gist is to provide a polyester in which 3 to 50% by weight of polyalkylene glycol having an average molecular weight of 2000 to 20000 is contained in polyalkylene terephthalate. , Average particle size consisting of cerium oxide and talc or cerium oxide and silica, and the surface of which is coated with amorphous silica
A hygroscopic polyester fiber comprising a polyester containing 0.05 to 10% by weight of particles of 0.1 to 3.0 μm.

In the present invention, the polyalkylene glycol includes those in which the terminal is etherified or esterified.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

In the present invention, the base polyester is polyalkylene terephthalate, and specifically, polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) are preferable. The polyalkylene terephthalate may contain a small amount of a copolymerization component, and examples of the copolymerization component include 5-sodium sulfoisophthalic acid, isophthalic acid, phthalic anhydride, an aromatic dicarboxylic acid component such as naphthalenedicarboxylic acid, and adipine. Acids, aliphatic dicarboxylic acid components such as sebacic acid, diethylene glycol, propylene glycol, 1,4-cyclohexanedimethanol, pentaerythritol, glycol components such as alkylene oxide adducts of bisphenol A and bisphenol S, 4-hydroxybenzoic acid,
Examples include hydroxycarboxylic acid components such as ε-caprolactone.

In the present invention, a polyalkylene glycol is contained in the polyester in order to impart hygroscopicity, but in order to impart good hygroscopicity, an average molecular weight of 20
It is necessary to use 00 to 20000 of polyalkylene glycol, and to add 3 to 50% by weight, preferably 5 to 30% by weight.

If the molecular weight of the polyalkylene glycol is too small, sufficient hygroscopicity will not be exhibited, and conversely if it is too large, the operability during spinning will be significantly reduced, which is not preferable. Further, if the content of the polyalkylene glycol is small, sufficient hygroscopicity is not exhibited, and conversely, if the content is too large, the operability during spinning is significantly reduced, which is not preferable.

In order to allow the polyalkylene glycol to be contained in the polyester, the polyalkylene glycol may be added during the production of the polyester, or the polyester and the polyalkylene glycol may be mixed and spun.
In the case of the latter, polyester and polyalkylene glycol are previously melt-kneaded using a uniaxial or biaxial kneader to produce a masterbatch, which may be added at the time of spinning, or both may be melt-mixed at the time of spinning. While spinning, you may spin.

As polyalkylene terephthalate, 5
-By using a copolymer of a compound having a sulfonate group such as sodium sulfoisophthalic acid, the hygroscopicity can be further improved. In this case, the amount of the copolymerization component is preferably 5 mol% or less of the total acid component, and if the amount of the copolymerization component is too large, the strength of the fiber is remarkably reduced, which is not preferable.

In the present invention, the polyester having a polyalkylene glycol as described above is composed of cerium oxide and silica or cerium oxide and talc, and the surface thereof is coated with amorphous silica. The average particle size is 0.1 to 3.0 μm.
The particles of m (lightproofing agent particles) are contained in an amount of 0.05 to 10% by weight.

The ratio of cerium oxide to silica (excluding amorphous silica coating the surface) or talc is 1 by weight.
5:85 to 50:50 is suitable. If the proportion of cerium oxide is too small, the effect of absorbing ultraviolet rays to improve the light resistance becomes insufficient, and if it is too large, the brightness of the polyester decreases.

Further, the amount of the amorphous silica coating the surface of the particles is preferably 15 to 25% by weight of the particles. If the amount of amorphous silica is too large, the ultraviolet absorption effect of cerium oxide is impaired, while if it is too small, the mechanical strength of the particles is low, and the surface activity is so strong that catalytic action of photolysis and thermal decomposition occurs. Therefore, it is not preferable.

The light-proofing agent particles have an average particle diameter of 0.1 to 3.0 μm.
m less than 0.1 μm, it is difficult to manufacture, the cost is high, and the dispersibility in polyester is poor.On the other hand, when it is more than 3.0 μm, the ultraviolet absorption effect is deteriorated. Light resistance is poor, and the color tone of polyester is poor.

As such light-proofing agent particles, those commercially available from Japan Inorganic Chemical Industry Co., Ltd. under the trade name of "Ceriguard" can be used.

The amount of the light-resistant agent particles added is required to be 0.05 to 10% by weight based on the polyester. If this addition amount is less than 0.05% by weight, excellent light resistance cannot be obtained,
If it exceeds 10% by weight, the particles tend to agglomerate to deteriorate the spinnability and deteriorate the color tone of the polyester.

The light-resistant agent particles may be dispersed in ethylene glycol or 1,4-by using a dispersant such as an anion activator, if necessary.
It is preferable to disperse it in glycol such as butanediol and add it during the production of polyester. Also, polyester (masterbatch) containing a large amount of light-resistant particles in advance.
It is also possible to employ a method in which the above is prepared and added at the time of spinning.

If the lightproofing agent particles are not evenly dispersed in the polyester, the ultraviolet absorption is rather weakened and the lightfastness is deteriorated, the transparency of the polyester is impaired, and the productivity during spinning is lowered. Or If the timing of adding the light-proofing agent particles is not appropriate, the particles agglomerate and the dispersibility of the particles deteriorates.

In order to uniformly disperse the lightproofing agent particles in the polyester, it is advisable to add the lightproofing agent particles to a polyester oligomer having an average degree of polymerization of 4 to 6 to carry out a polycondensation reaction. Since polyalkylene terephthalate is excellent in terms of cost and productivity, usually terephthalic acid and a diol are directly esterified to synthesize a polyester oligomer having an average degree of polymerization of 7 to 10 and polycondensed. Manufactured by the method. Therefore, a polyalkylene glycol or a diol solution of polyalkylene glycol is added to the polyester oligomer having an average degree of polymerization of 7 to 10 to depolymerize the polyester oligomer to obtain an average degree of polymerization of 4
It is preferable in terms of light resistance, transparency, and productivity to employ a method in which light resistance agent particles are added and polycondensation is performed after forming the polyester oligomers of 6 to 6.

The polycondensation reaction in producing the polyester is usually carried out under a reduced pressure of about 0.01 to 10 torr at 220 to 310 ° C.
It is preferably carried out at a temperature of 235 to 290 ° C until the intrinsic viscosity becomes 0.5 or more.

Further, additives such as an antioxidant such as a hindered phenol compound, a cobalt compound, a fluorescent agent, a color tone improving agent such as a dye, a pigment such as titanium dioxide and the like may be contained.

The polyester fiber of the present invention can be obtained by spinning a polyester composition containing polyalkylene glycol and lightproofing agent particles by a conventional method. In addition, as long as the effect of the present invention is not impaired, a composite fiber with other components may be used.

The polyester fiber of the present invention can be used as either a long fiber or a short fiber, and may be subjected to post-processing such as crimping, false twisting or treatment with a chemical solution, if necessary. it can.

[0030]

Although the reason why the polyester fiber of the present invention exhibits excellent light resistance is not clear, it is generated by particles of cerium oxide and talc or cerium oxide and silica absorbing and absorbing ultraviolet energy. The silica coating the particles blocks the radicals and suppresses the radical generation of the polymer. Therefore, it is presumed that the polyester containing the polyalkylene glycol is prevented from absorbing ultraviolet rays and being deteriorated. Further, since it is possible to prevent the generation of coarse particles caused by agglomeration of particles composed of cerium oxide and talc or cerium oxide and silica by polyalkylene glycol, it is possible to suppress the decrease in ultraviolet absorption ability due to the increase in particle size. Presumed to be done.

[0031]

Next, the present invention will be described specifically with reference to examples. In addition, the measuring method of the characteristic value in an Example is as follows. (a) Intrinsic viscosity ([η]) Measured at a temperature of 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent. (b) Tensile strength Tensilon UTM-4-100 type manufactured by Oriental Co.,
It was measured at a sample length of 50 cm and a pulling speed of 50 cm / min. (c) Moisture absorption rate A tubular knitted fabric is prepared, and the humidity of this is measured at 25 ° C and 60% RH to measure the weight W ₀ . Then, this tubular knitted fabric is dried at 80 ° C. for 6 hours under a reduced pressure of 2 Torr, and allowed to stand in a thermo-hygrostat set at 34 ° C. and 90% RH for 6 hours, and then the weight W ₁ is measured. Then, the moisture absorption rate is calculated by the following equation. Moisture absorption rate (%) = [(W ₁ −W ₀ ) / W ₀ ] × 100 (d) Light resistance The light fastness to dyeing was measured according to JIS L-0841-74.

The "Seriguard" used in Examples and Comparative Examples is a trade name of Japan Inorganic Chemical Industry Co., Ltd. and has the following composition. Cerigard T-3018; particles of cerium oxide and talc coated on the surface with amorphous silica, with a weight ratio of cerium oxide: talc: amorphous silica of 30:52:18 Cerigard S-3018; oxidation Cerium and silica particles coated on the surface with amorphous silica, with a weight ratio of cerium oxide: silica: amorphous silica of 30:52:18 Serigard T-2018; consisting of cerium oxide and talc The surface of the particles is coated with amorphous silica, and the weight ratio of cerium oxide: talc: amorphous silica is 20:62:18.

Example 1 A slurry of terephthalic acid and ethylene glycol in a molar ratio of 1 / 1.6 was continuously fed to an esterification reactor in which bis (β-hydroxyethyl) terephthalate and its oligomer were present, and the slurry was heated to 250 at normal pressure. An esterification reaction was carried out at a temperature of ° C for a residence time of 6 hours to continuously obtain an esterification product having an average degree of polymerization of 7.5. To 49.5 kg of this esterified product, 5.4 kg of polyethylene glycol having an average molecular weight of 8500 was added, and after stirring and mixing for 30 minutes, Celigard T-3018
11 kg of 10% by weight ethylene glycol solution was added to 1 mol of all acid components, and 2 × 10 ^-4 mol of antimony trioxide and 1 kg of 5% ethylene glycol solution of sodium acetate were added. Mol% 5-sodium sulfoisophthalic acid ethylene glycol ester (S
IP) and reduce the pressure in the polymerization reactor until finally
Polycondensation was carried out at a temperature of 0.5 torr and 270 ° C. for 4 hours. The obtained polyester had a good color tone and [η] was 0.69. This polyester is melt-spun at a spinning temperature of 290 ° C,
The undrawn yarn was wound up at a speed of 1400 m / min. This unstretched yarn was supplied to a stretching machine, preheated at 80 ° C., stretched 3.5 times while being in contact with a heat plate at a temperature of 150 ° C., heat-treated and wound to obtain a 75 d / 36 f filament yarn. The yarn-forming property is good, and the obtained yarn has a strength of 4.4.
g / d, elongation 38%, moisture absorption 4.2%, dyeing light fastness 5
It showed high quality and excellent characteristics.

Examples 2 to 9 and Comparative Examples 1 to 7 Polyesters were produced and spun into yarn in the same manner as in Example 1 using the polyalkylene glycol, SIP and the added particles shown in Table 1. In each of the examples, the spinnability was good, but in Comparative example 2, the rate of increase in the pack pressure was high, the spinning operability was very poor, and in Comparative example 3, the color tone of the polymer was extremely poor.

Reference Example 49 kg of an esterification product obtained in the same manner as in Example 1 was mixed with 10% by weight of Celigard T-3018 in 10% ethylene glycol solution.
kg, and after stirring and mixing for 30 minutes, 2 × 10 ^-4 mol of antimony trioxide was added to 1 mol of all acid components, the pressure was reduced in the polymerization reactor, and finally the temperature was 0.5 torr and 285 ° C. So 2
A time polycondensation reaction was performed. The obtained polyester had a good color tone and [η] was 0.69. This polyester was spun into yarn in the same manner as in Example 1. However, since the polyester contained a large amount of coarse particles, the rate of increase in the pack pressure during spinning was high and the operability was poor, and the obtained yarn showed almost no hygroscopicity. It was

Table 1 shows characteristic values and the like of the polyesters and yarns obtained in the above Examples, Comparative Examples and Reference Examples.

[0037]

[Table 1]

[0038]

EFFECTS OF THE INVENTION According to the present invention, there is provided a polyester fiber which can be produced with good spinnability and has excellent hygroscopicity and light resistance.

Claims (1)

[Claims] 1. A polyalkylene terephthalate containing 3 to 50 polyalkylene glycol having an average molecular weight of 2000 to 20000.
Polyester contained by weight% consists of cerium oxide and talc or cerium oxide and silica, and the surface is coated with amorphous silica. Average particle size 0.1-3.0 μm
A hygroscopic polyester fiber comprising a polyester containing 0.05 to 10% by weight of the above particles.