Polyester resin composition and fiber

Polyester resin composition and fiber

Technical Field of the Invention The present invention relates to a polytrimethylene terephthalate polyester resin composition containing titanium oxide and a dull polyester fiber showing appropriate gloss obtained by melt-spinning the resin composition; more specifically, The present invention relates to a polytrimethylene terephthalate resin composition improved by using a titanium oxide microdispersion, which can significantly inhibit the pressure increase of the spinning head assembly caused by the titanium oxide agglomerates during the melt spinning process, and the decrease in fiber strength and An improved polytrimethylene terephthalate fiber obtained in a spinning-drawing process with low fiber abrasion.

The present invention relates to such a polytrimethylene terephthalate fiber, which solves the peculiar high friction coefficient problem. As a result, yarn interruption and fluffing are less in the spinning and post-processing steps, and the spinnability is excellent.

Background technique

Polytrimethylene terephthalate (hereinafter abbreviated as PTT) fiber is expected to have a soft hand feel similar to nylon fiber derived from a low elastic modulus, excellent elastic recovery and easy dyeability, and a pair of polyester fibers. Ethylene phthalate-like fibers with non-iron, dimensional stability and yellowing resistance are currently being used in clothing and carpets to produce this characteristic.

When using synthetic fibers such as polyethylene terephthalate (hereinafter abbreviated as PET) fibers and nylon fibers as clothing, the luster of the fibers can be controlled according to the application by adding titanium oxide to the fibers (titanium oxide). Used as a so-called matting agent). For example, consumers do not need the lining to have gloss, so 0.2-1% by weight of titanium oxide is added to the fiber for matting. In applications that require bright colors such as raincoats and women's clothing underlays, a small amount of titanium oxide is added to keep it from tarnishing.

In this way, changing the fiber gloss by changing the amount of titanium oxide is necessary for both clothing and carpet PTT fibers. However, according to research conducted by the present inventors, it was discovered for the first time that there are some major problems as shown below when manufacturing PTT fibers containing titanium oxide.

First of all, the biggest problem is that when titanium oxide is added to PTT, unless the method of adding titanium oxide is thoroughly studied, a large amount of titanium oxide agglomerates will be contained in the obtained polyester resin composition. Compared with the case of PET and polybutylene terephthalate (hereinafter abbreviated as PBT) having a similar structure, the formation of such agglomerates is easier.

If a resin composition containing a large amount of titanium oxide agglomerates is melt-spun, the agglomerates will block the filter of the spinneret assembly, and the pressure of the spinneret assembly will rise in a short time, resulting in easy spraying. Pollution of the silk holes, or the fact that thread breaks and fluffing occur more frequently, causing major problems in spinnability and spinning yield. In addition, once there are a large number of coarse aggregates in the obtained fiber, it will become a defect, or the fiber strength will be significantly reduced, or it will be easy to fluff.

In addition, such agglomerates have an adverse effect on the wear properties of PTT chips and their fibers. The PTT composition is different from PET and PBT with similar structures. After polymerization, the crystallization speed is fast when the slice is formed by quenching, and it becomes a sheet with high crystallinity. According to investigations, this kind of sheet is relatively fragile and becomes powder due to friction in the conveying, drying and extruder. This phenomenon is aggravated with the increase of the number of aggregates. The production of powder leads to a decrease in the yield due to polymer loss, and the fluffing phenomenon is aggravated due to entrapment of air bubbles. On the other hand, for PET and PBT, this phenomenon hardly occurs due to the low crystallinity of the sheet. In addition, agglomerates also cause a decrease in the abrasiveness of the fibers. Since the PTT fiber has a Z-shaped large-bend configuration, the intermolecular force is lower than that of the PET and PBT fibers, and thus the abrasion property is reduced. If the aggregates increase, the degree of the abrasion property degradation is further increased. In contrast, for PET and PBT fibers with a near-stretched conformation, the adverse effect of agglomerates on abrasion performance is not as great as that of PTT.

Another problem with the titanium oxide-containing PTT is that the resin composition is thermally decomposed in the drying step performed before spinning, so that the amount of acrolein and allyl alcohol produced increases compared to the PTT that does not substantially contain titanium oxide. Acrolein and allyl alcohol are toxic and tear-inducing, and are chemical substances that have a harmful effect on the operating environment, so reducing the amount of them is an important issue.

The final problem is that the PTT fiber has a large friction coefficient in the synthetic fiber, which belongs to the inherent characteristics of the PTT fiber. For example, from the fiber-metal friction coefficient, when there is no finishing agent on the fiber surface, in the 50d/36f fiber, the value of the widely used polyethylene terephthalate fiber is 0.295, while the value of PTT fiber It is 0.378. That is to say, it is easy to understand that compared with other widely used synthetic fibers, PTT fibers have significant rubber properties.

Therefore, because PTT has a significantly high coefficient of friction, the coefficient of friction between the wire frame and the drum during spinning-drawing, or during weaving, false-twist processing, etc., increases beyond what can be achieved from PET and PBT fibers. The degree of imagination is prone to breakage and fluffing. However, no solution to the above-mentioned problem has been disclosed so far.

For example, US Patent Publication No. 5798433 discloses a method of using 30 to 200 ppm of titanium oxide as a polymerization catalyst in terms of titanium atomic weight. However, in this first case, there is no mention of the dispersibility of titanium oxide and the problems to be solved. In addition, the titanium oxide used is an amorphous titanium oxide/silicon oxide co-precipitate co-precipitated after hydrolysis of titanium alkoxide and silanol. It has a different chemical structure and crystallinity from the crystalline titanium oxide used as a matting agent. Structure, so the extinction performance is low, the dispersion is poor, this method is not applicable. In addition, the amorphous titanium oxide/silicon oxide co-precipitate used in this first example has high reactivity. Once the addition amount reaches 100 ppm or more, side reactions will occur, causing the resulting polymer to turn yellow.

In the example of U.S. Patent No. 3681188, a PTT containing 0.1% by weight of titanium oxide is disclosed. But there is no mention of the technical significance of the dispersibility of titanium oxide.

In addition, Japanese Patent Application Laid-Open No. 62-18423 describes a method for preparing a titanium slurry for polyester, but PTT is not specifically described, and the description is actually made for PET. In addition, in this method, a titanium oxide dispersion is prepared by mixing a strong acid such as titanium oxide and phosphoric acid with a strong base such as sodium hydroxide and tetraethylammonium hydroxide in ethylene glycol. These additives in 3-propanediol have an effect on the surface of titanium oxide, and there is a tendency for aggregates to increase. There is no hint about the wear and friction coefficient of the fiber after adding titanium oxide to the PTT fiber, as well as the problem of decomposition products and their solutions.

Disclosure of the Invention The purpose of the present invention is to obtain a spinning that adjusts the gloss, reduces the pressure rise of the spinneret, reduces the interruption and fluffing of the spinning process, and can suppress the reduction of fiber strength and abrasion resistance. A titanium oxide-containing PTT resin composition capable of spinning PTT fibers with excellent abrasion resistance and a reduced friction coefficient. The specific object of the present invention is to provide a titanium oxide agglomerates whose formation is suppressed, using a 1,3-propanediol dispersion containing titanium oxide, and under polymerization in which the formation of titanium oxide agglomerates is inhibited, titanium oxide is finely dispersed PTT resin composition.

Another specific object of the present invention is to provide a PTT resin composition that does not actually contain titanium oxide, which suppresses the production of by-products such as acrolein and allyl alcohol in the drying step before spinning, and is most suitable PTT resin composition made of fiber.

A more specific object of the present invention is to provide a polymerization technology for obtaining PTT, and the obtained resin composition and fiber thereof by adding a specific stabilizer to the polymerization to solve the above-mentioned problems.

The inventors of the present invention found that, while fully dispersing titanium oxide in a solvent in advance, adding a titanium oxide dispersion liquid in which the by-produced titanium oxide aggregates are removed at the PTT polymerization stage under specific conditions can obtain a finely dispersed titanium oxide PTT Resin composition.

Based on this PTT resin composition containing micro-dispersed titanium oxide, the present invention has found that there is no problem of spinneret assembly pressure rise and fiber strength reduction, high wear performance, and at the same time, the friction coefficient is significantly reduced compared with PTT without titanium oxide , The results show excellent spinning performance.

According to the present invention, in the coexistence of a phosphorus compound and/or hindered phenolic antioxidant, the above-mentioned polycondensation reaction can significantly reduce the amount of acrolein and allyl alcohol produced by the titanium oxide-containing composition after polymerization when it is dried.

The object of the present invention is solved by a polyester resin composition having an intrinsic viscosity of 0.4 to 2 that basically satisfies the following conditions (1) to (3).

(1) It should be composed of a polyester resin composed of 90% by weight or more of polytrimethylene terephthalate (2) It should contain 0.01 to 3% by weight of titanium oxide with an average particle size of 0.01 to 2 microns (3) Titanium oxide particles For the aggregate formed by the aggregation, the longest part with a length of more than 5 microns should be less than 25 pieces/mg resin.

The polyester resin composition of the present invention is suitable for fiber molding by a melt spinning method, and is used in the form of polyester fibers, films, and molded products, and is particularly used as a fiber.

The PTT resin composition of the present invention is composed of a polyester resin containing at least 90% by weight of PTT. The PTT referred to herein refers to polytrimethylene terephthalate obtained by using terephthalic acid as the acid component and 1.3-propylene glycol (trimethylene glycol) as the diol component. In the resin composition of the present invention, the fiber composition component PTT of the present invention may contain one or more copolymer components, other polymers, inorganic substances, and organic substances that account for less than 10% by weight of the resin composition or fiber weight.

The copolymerization component that the PTT mentioned in the present invention may contain includes, for example, 5-sodium isophthalate sulfonate, 5-potassium isophthalate sulfonate, and 2,6-naphthalenedicarboxylic acid-4-sulfonic acid Sodium, 3,5-dicarboxybenzenesulfonate tetramethylphosphonium salt, 3,5-dicarboxybenzenesulfonate tetrabutylphosphonium salt, 3,5-dicarboxybenzenesulfonate tributylmethylphosphonium salt, 2,6 -Dicarboxynaphthalene-4-sulfonic acid tetrabutylphosphonium salt, 2,6-dicarboxynaphthalene-4-sulfonic acid tetramethylphosphonium salt, 3,5-dicarboxybenzenesulfonate ammonium salt, 1,2-butane Glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, heptanediol, octanediol, sebacic Alcohol, dodecanediol, 1,4-cyclohexanediol, 1,3-cyclohexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,3- Cyclohexanedimethanol, 1,2-cyclohexanedimethanol, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, dodecanedi Acid, 2-methylglutaric acid, 2-methyladipic acid, fumaric acid, maleic acid, itaconic acid, 1,4-cyclohexanedioic acid, 1,3-cyclohexanedioic acid, 1, Ester forming monomers such as 2-cyclohexanedioic acid. Furthermore, even if it is not actively copolymerized, it is possible to copolymerize 3-propylene glycol and dimer bis(3-hydroxypropyl) ether at a copolymerization ratio of 0.01 to 2% by weight. This is because 1.3-propylene glycol undergoes dehydration and dimerization as a side reaction in the polymerization, and the resulting dimer can be copolymerized in the polymer backbone.

The limiting viscosity [η] (also called intrinsic viscosity) of the polymer constituting the polyester resin composition of the present invention must be between 0.4 and 2.0. When the intrinsic viscosity is less than 0.4, the polymerization of the resin composition is too low, so in addition to lowering the strength of the obtained fiber, the spinnability becomes unstable. Conversely, if the limiting viscosity exceeds 2.0, the melt viscosity is too high, and the gear pump cannot be used for smooth metering, resulting in poor spinning and reducing spinnability. Furthermore, with a preferable limiting viscosity of 0.6 to 1.5 (more preferably 0.6 to 1.4), a PTT fiber having excellent strength and spinnability can be obtained.

The polyester resin composition of the present invention must contain a resin composition having an average particle diameter of 0.01-2 microns from the viewpoint of matting effect and reduction of friction coefficient, and its content relative to the weight of the fiber is 0.01-3 wt. %. The type of titanium oxide that can be used in the present invention can be either anatase type or rutile type, and it can also be surface-treated with inorganic substances such as alumina and silica, and organic groups such as hydrocarbon groups and silyl groups. The crystallinity of the titanium oxide used in the present invention is preferably 50% or more, and more preferably 70% or more. The type of crystal should be low in hardness and low in friction coefficient. From the viewpoint of good dispersibility to 1,3-propanediol, anatase type titanium oxide is preferably used. In addition, in order to suppress the photodecomposition caused by titanium oxide, antimony may be contained in an amount of 0.1 to 1% by weight with respect to the amount of titanium oxide. In addition, it may be redispersed in organic solvents such as water and ethanol, and titanium oxide from which aggregates have been removed may be used. It is preferable to use titanium oxide for chemical fibers that is generally commercially available. The average particle size of titanium oxide must be 0.01 to 2 micrometers, and 0.05 to 1 micrometers is particularly preferable. Particles with an average particle size of less than 0.01 microns are difficult to be practical, while particles over 2 microns are likely to clog the filter plate of the spinneret assembly, causing the filtration pressure to rise in a short period of time. Because the nozzle holes of the spinneret are easily contaminated, it has to Frequently sweep the surface of the spinneret. The particle size distribution of the tubular titanium oxide is not particularly limited, but from the viewpoint of suppressing the pressure rise of the spinneret assembly, the component with a particle size of 1 micron or more is preferably less than 20% by weight of the total titanium oxide, and more preferably 10% by weight or less.

In the present invention, the purpose of the resin composition containing titanium oxide is to adjust the gloss of the obtained fiber to a desired level according to the needs of the application, and to reduce the friction coefficient of the fiber. Adjusting the content of titanium oxide can change the gloss of the fiber. When high gloss is desired, the content of titanium oxide relative to the weight of the resin composition and fiber may be 0.01 to 0.1% by weight, preferably 0.03 to 0.07% by weight. However, when high gloss is desired, the titanium oxide content can be as close to 0 as possible, but once the gloss is too strong, it will make people feel dazzling and tacky. Therefore, when high gloss is desired, at least 0.01% by weight of titanium oxide must also be contained. When it is desired to suppress gloss, it may contain 0.1 to 1% by weight of titanium oxide, and when it is desired to suppress gloss as much as possible, it may contain 1 to 3% by weight of titanium oxide.

The degree to which the friction coefficient of the fiber decreases due to the addition of titanium oxide also depends on the amount of titanium oxide added, and may affect several tens of percent at most. This significant reduction in friction coefficient is unique to PTT fibers, but it does not have this property for PET and PBT fibers. From the viewpoint of reducing the coefficient of friction, the content of titanium oxide is also important, and when the content of titanium oxide in the fiber is less than 0.01% by weight, the effect of reducing the coefficient of friction is small. Conversely, once it exceeds 3% by weight, the friction coefficient no longer decreases. Therefore, the value is preferably 0.03 to 2% by weight, and more preferably 0.04 to 2% by weight.

Titanium oxide particles become agglomerates due to agglomeration, the longest part of which exceeds the number of agglomerates of 5 microns, in the polyester resin composition of the present invention must be less than 25 / mg of resin (this unit represents 1 The number of aggregates contained in the milligram resin composition.). The number of such agglomerates is a value measured by the measurement of titanium oxide agglomerates described later in [2]. Satisfying this condition can make the polyester resin composition of the present invention and the titanium oxide in the fiber highly dispersed. As a result, the brittleness of the resin composition can be reduced, the friction of the fiber can be reduced, wire breakage and fluffing can be suppressed, and the friction coefficient can be reduced. . The agglomerate referred to in the present invention refers to a polyester resin composition and its fibers, or in the titanium oxide dispersion introduced into the reactant at the time of manufacture, the existing titanium oxide particles are actually integrated with each other. Particle aggregates. This kind of agglomerate is in the shape of a block. Therefore, in order to solve the above-mentioned problem, the longest part of the arbitrary length of the agglomerate must be specified below the specific value.

The aggregation of titanium oxide and its dispersion state can be confirmed by observing the method of melting the resin composition into a thin layer to obtain a thin film with an optical microscope. When the number of aggregates exceeds 25/mg resin, it may become brittle, or the pressure of the spinneret assembly will rise in a short period of time, or the spinneret is easy to contaminate, and it is easy to break and fluff, and it is not stable. For industrial production. Moreover, the friction coefficient of the obtained fiber is also increased. Therefore, it is preferably 15 pieces/mg resin or less, more preferably 10 pieces/mg resin or less, and most preferably 5 pieces/mg resin or less. The aggregates in the fiber obtained by this method are preferably 7 per mg of fiber (this unit represents the number of aggregates contained in 1 mg of fiber.) or less, more preferably 3 per mg of fiber or less, and most preferably 1 /Mg fiber or less. The inventors of the present invention found that several filters with reduced internal filtration surface area and small pore diameter were overlapped to form a spinneret assembly, and the molten resin composition was passed through it, and the pressure of the spinneret assembly was observed in a short time. The degree of rise, after studying with this method, found that the size of the pressure rise of the assembly within a certain period of time is related to the number of aggregates. When the agglomerates increase, the pressure of the spinneret assembly increases in a short time due to the increase in the agglomerates clogging the filter. Conversely, if the agglomerates are reduced, the pressure rise of the spinneret assembly is extremely small. For example, the polyester resin composition whose moisture content is reduced to 100 ppm or less after being melted at 265°C in an extruder passes through a sand filter layer (filter area is 660 square millimeters and a thickness of 2 cm). It can pass 20 mesh but not 28 mesh filter; then it is passed through (1) 50 mesh filter, (2) 150 mesh filter, (3) 300 mesh filter, (4) under the filter area of 660 square millimeters. A sintered filter with a pore size of 20 microns, (5) a filter with a pore size of 50 mesh; then at a spinning speed of 25 g/min, 12 holes with a pore size of 0 are opened. The spinneret with 23 mm micropores enters the atmosphere. At this time, the pressure from the exit of the extruder to the sand filter layer, and the rise value after 20 hours after 5 hours from the start of spinning is less than 40 kg/cm². The industrial spinning device (in this case, the filtration area is much larger than this model test) can be used to stably spin and stretch under the condition that the pressure rise of the spinneret assembly is small, and the quality of the obtained fiber is also excellent. The pressure rise below 40 kg/cm² generally corresponds to the upper limit of the number of aggregates in the resin composition specified in the present invention of 25 per mg of resin. Once the pressure rise value exceeds 40 kg/cm², thread breakage and fluffing will increase, the spinneret is easily contaminated, and the friction coefficient of the fiber surface also has the effect of reducing. The pressure rise value is as small as possible, preferably 30 kg/cm² or less, more preferably 20 kg/cm² or less.

The polyester resin composition of the present invention contains a phosphorus compound corresponding to 5 to 250 ppm of elemental phosphorus and/or 0.002 to 2% by weight of hindered phenolic antioxidant.

The resin composition or fiber of the present invention preferably contains a phosphorus compound corresponding to 5 to 250 ppm of elemental phosphorus relative to the weight of the resin composition or fiber. It is known that when PTT is dried and heated for a long time above 100°C, there will be a small amount but partial decomposition to produce acrolein and allyl alcohol. However, according to research conducted by the inventors of the present invention, a PTT composition containing titanium oxide used as a matting agent has a considerably larger amount of these decomposition products than PTT containing no titanium oxide. However, it was surprisingly found that by containing a phosphorus compound in the resin composition, the productivity of these decomposition products was greatly suppressed. In addition, the phosphorus compound added in this way is used in each process from the polymer to the clothing product, in various stages such as melt polymerization, solid phase polymerization, chip drying at high temperature, melt spinning, washing, heat setting, and dyeing, etc. It can produce great effects for preventing the coloring of the composition or its fibers and improving the melt stability.

The phosphorus compound is preferably an organophosphorus compound. From the standpoint of its excellent effects of inhibiting the production of acrolein and allyl alcohol, preventing coloring, and melting stability, the following phosphates are particularly preferable: O=P(OR1)(OR2) (OR3) or phosphite: P(OR4)(OR5)(OR6). In the formula, R1, R2, R3, R4, R5, and R6 may be the same or different, and are selected from hydrogen atoms or organic groups with 1-30 carbon atoms, alkali metals and alkaline earth metals. In the case of an organic group having 1 to 30 carbon atoms, part or all of the hydrogen atoms may be substituted with halogen atoms, ester groups, carboxyl groups, amide groups, amino groups, imino groups, ether groups, and the like.

Preferable examples of these phosphorus compounds include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, and trioctyl phosphate. , Dimethyl ethyl phosphate, dimethyl phosphate, methyl phosphate, 3-hydroxypropyl phosphate, bis(3-hydroxypropyl) phosphate, tris(3-hydroxypropyl) phosphate, triphosphate Phenyl ester, trimethyl phosphite, triethyl phosphite, tripropyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl phosphite, trioctyl phosphite , Dimethyl ethyl phosphite, dimethyl phosphite, methyl phosphite, 3-hydroxypropyl phosphite, bis(3-hydroxypropyl) phosphite, tris(3-hydroxypropyl) phosphite Base) ester, triphenyl phosphite, sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate, dimethyl phosphate sodium salt, methyl phosphate disodium salt, phosphoric acid, phosphorous acid, ethyl diethylphosphonoacetate, etc. ; From the viewpoint of coloring prevention, excellent melting stability effect and low polymerization inhibition ability, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, phosphoric acid, phosphorous acid and ethyl diethylphosphonoacetate are particularly preferred Wait.

The amount of phosphorus compound contained in the resin composition or fiber of the present invention can be expressed by the weight percentage of the element phosphorus contained in the resin composition and fiber, and its numerical range is preferably in the range of 5 to 250 ppm. Less than 5 ppm cannot fully exhibit the effect of suppressing the generation of decomposition products, and more than 250 ppm, although these effects are sufficient, it is difficult to perform melt polymerization and solid phase polymerization due to partial deactivation of the polymerization catalyst. It is preferably 35 to 150 ppm, more preferably 50 to 120 ppm.

In order to achieve the purpose of suppressing the production of acrolein and allyl alcohol, preventing coloring and improving melt stability, it is preferable to add a hindered phenolic antioxidant to the resin composition and fibers of the present invention. Of course, it can also be used together with the above-mentioned phosphorus compounds. Such hindered phenolic antioxidants can be used known products. Specific examples include: pentaerythritol-tetra-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,1 ,3-Tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl) 4-hydroxybenzyl)benzene, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-di Methylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6- Dimethylbenzene) isophthalic acid, triethylene glycol bis[3-(3-tert-butyl 5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol bis[3 -(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2-thio-2-ethylenebis[3-(3,5-di-tert-butyl-4- Hydroxyphenyl)propionate] and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Among them, pentaerythritol-tetra-[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyl) are preferred. Phenyl) propionate.

The amount of the hindered phenol oxidation stabilizer is preferably 0.002 to 2% by weight relative to the weight of the resin composition and fiber. This is because if it exceeds 2% by weight, it may be colored, and even if the amount exceeds 2% by weight, the ability to improve the melt stability is already saturated. On the other hand, when it is less than 0.002% by weight, the effect of suppressing the production of acrolein and allyl alcohol is small. It is preferably 0.02 to 1% by weight.

In addition, once the resin composition and fiber of the present invention contain a cobalt compound, in addition to the effect of suppressing the production of acrolein and allyl alcohol, it also has the effect of remarkably improving the whiteness of the resin composition and fiber. As the cobalt compound, cobalt acetate, cobalt formate, cobalt carbonate, cobalt propionate, etc. can be used. The polyester resin composition of the present invention further contains a cobalt compound corresponding to 1 to 25 ppm of elemental cobalt. When it is less than 1 ppm, the effect of suppressing the generation of decomposition products and improving the whiteness cannot be exerted, while when it exceeds 25 ppm, the resin composition and fibers become black, and the use is limited. Therefore, it is preferably 2 to 30 ppm, more preferably 3 to 15 ppm.

The polyester resin composition and fiber of the present invention may be copolymerized or mixed with various additives if necessary, such as matting agents other than titanium oxide, heat stabilizers, defoamers, toners, and flame retardants. , Antioxidants, ultraviolet absorbers, infrared absorbers, crystal nucleating agents and brighteners, etc.

There are no particular restrictions on the production method of the polyester resin composition of the present invention, and preferred methods are described below.

The polyester resin composition of the present invention can be obtained as follows: a lower alcohol ester derivative of terephthalic acid, such as a dicarboxylic acid based on terephthalic acid or dimethyl terephthalate, and 1,3 -Propylene glycol reacts to produce 1,3-propylene glycol terephthalate and/or its oligomers, and then undergoes polycondensation reaction to produce polyester. In this method, at any stage between the start of the reaction and the end of the reaction In any case, after adding titanium oxide to the solvent and stirring, the operation of removing the agglomerates of titanium oxide particles is performed, and the obtained dispersion in the solvent is added to the reactant, and then the polycondensation reaction is completed.

The important point here is the preparation method of the dispersion liquid from which aggregates are removed.

First, powdery titanium oxide is added to a solvent to make it 0.1 to 70% by weight, and it is sufficiently stirred to prepare an apparently uniform dispersion. The preferred content of titanium oxide in the solvent is 10-50% by weight. The solvent used is not particularly limited, and 1,3-propanediol, ethylene glycol, 1,4-butanediol, methanol, toluene, etc. can be used, but 1,3-propanediol is particularly preferred. The stirring method is not particularly limited, and high-efficiency stirring methods such as high-speed mixers, homogenizers, kneaders, etc. are preferred. Moreover, ball mill and bead mill can also be used together after stirring. The stirring time is preferably 10 to 48 hours.

Although the titanium oxide dispersion liquid obtained in this way is uniform in appearance, it contains a large amount of agglomerates of titanium oxide particles. For example, when this dispersion liquid is observed with a microscope, it can be found that there are agglomerates of titanium oxide everywhere. The titanium oxide dispersion in this state is used to polymerize PTT. Since it contains a large amount of titanium oxide agglomerates, only a resin composition with a high rate of pressure rise of the spinneret assembly can be obtained. Although mechanical pulverization can also be used to pulverize the agglomerates, compared with this pulverization operation, the operation of removing the agglomerates from the dispersion is more effective, simple and economical.

Therefore, it is necessary to remove agglomerates from the apparently uniform titanium oxide dispersion. Known methods can be used for the operation of removing aggregates, and examples thereof include centrifugal separation and filter filtration. Since centrifugal separation is the simplest and most effective, it is the best method to remove agglomerates. The centrifugal separator used is not particularly limited, and it can be continuous or intermittent. When performing centrifugal separation, attention should be paid to the rotation speed and separation time. When the speed is too high and the time is too long, the finely dispersed titanium oxide will also be centrifuged and removed from the dispersion; on the contrary, if the rotation speed is too slow and the time is too short, then Insufficient separation. The rotation speed is preferably at least 500 revolutions per minute, particularly preferably 2000 to 10,000 revolutions per minute, and the treatment time is preferably 2 to 90 minutes. When a filter is used for filtration, the pore size of the filter used is preferably 200-2000 mesh, particularly preferably 300-700 mesh. In this case, several filters can be passed, and it is also possible to pass the same filter several times. There are no particular restrictions on the type of filter, and organic products such as metal products, ceramic products, and non-woven fabrics can be cited.

The titanium oxide agglomerates removed in this way are an agglomerate of titanium oxide particles with the longest part exceeding 5 microns, and it is preferable to remove them as much as possible. The titanium oxide content in the titanium oxide dispersion liquid thus obtained is preferably in the range of 10 to 30% by weight.

The polymerization conditions are described in detail below. As for the polymerization method, basically publicly known methods can be adopted.

In other words, the lower alcohol derivative of terephthalic acid such as terephthalic acid or dimethyl terephthalate is reacted with 1,3-propanediol at a temperature of 200 to 240°C, and then the temperature is below 1 Torr Preferably, it is subjected to a polycondensation reaction at a temperature of 250 to 290°C, preferably at a temperature of 260 to 280°C, under a reduced pressure of 0.5 Torr or less to obtain a resin composition.

When feeding, the feeding ratio between lower alcohol derivatives of terephthalic acid such as terephthalic acid or dimethyl terephthalate and 1,3-propanediol is 1:1.3 to 1:3, preferably 1 :1.5~1; 2.5. When 1,3-propanediol is less than 1:1.3, the reaction time will be significantly longer and the resin composition will be colored; on the contrary, when 1,3-propanediol is more than 1:3, bis(3-hydroxypropyl) ) The amount of ether produced increased.

In order to react a lower alcohol derivative of terephthalic acid such as terephthalic acid or dimethyl terephthalate with 1,3-propanediol, a catalyst is preferably used. Examples of preferred catalysts include titanium alkoxides represented by titanium tetrabutoxide and titanium tetraisopropoxide, cobalt acetate, calcium acetate, magnesium acetate, zinc acetate, titanium acetate, and amorphous titanium oxide precipitates. , One or more substances among amorphous titanium oxide/silicon oxide coprecipitate, amorphous titanium oxide/zirconia coprecipitate, etc. The amount of the transesterification catalyst used is preferably 0.02 to 0.15% by weight.

A polycondensation catalyst must be used. Examples of such polycondensation catalysts include titanium alkoxides represented by titanium tetrabutoxide and titanium tetraisopropoxide, antimony acetate, and antimony trioxide. Titanium alkoxides typified by titanium tetrabutoxide and titanium tetraisopropoxide are preferred because of the fast reaction rate. The amount of the polycondensation catalyst used is preferably 0.03 to 0.15% by weight.

The phosphorus compounds, hindered phenolic antioxidants and cobalt compounds used in the present invention can be added at any stage of the polymerization, or can be added at once or several times. The addition of phosphorus compounds is after the end of the transesterification reaction and does not hinder the transesterification. It reacts, and the coloring of the resin composition is most suppressed, so it is preferable. Where the temperature of the reactant is higher than the boiling point of the phosphorus compound used, the direct addition cannot be added to the predetermined amount due to evaporation. In this case, it is particularly preferable to dissolve it in 1,3-propanediol at least once at a temperature of 50°C or higher, and to add it after reacting with 1,3-propanediol to increase the boiling point. With this method, the required amount of phosphorus element can be imparted to the resin composition. Furthermore, cobalt can also be used as a compound catalyst.

Regarding the titanium oxide dispersion liquid from which the titanium oxide aggregates are removed, it is preferable to add a catalyst, a phosphorus compound, a hindered phenolic antioxidant, and a cobalt compound. This is because if the titanium oxide dispersion liquid to remove the titanium oxide aggregates is added first, and then the catalyst, phosphorus compound, hindered phenolic antioxidant, and cobalt compound are added, the catalyst, phosphorus compound, hindered phenolic antioxidant, and cobalt compound are The local pH of the part corresponding to the polymer surface increases, and the titanium oxide may aggregate under the impact. Therefore, a preferred method is to add a catalyst, a phosphorus compound, a hindered phenolic antioxidant, and a cobalt compound, and then thoroughly stir for at least 1 minute or more, and then add the titanium oxide dispersion liquid to remove the titanium oxide aggregates. In addition, if the temperature during addition exceeds 250°C, the possibility of aggregation under thermal shock increases. Therefore, it is preferable to add at a temperature lower than 250°C.

Once the polyester resin composition thus obtained reaches a predetermined limiting viscosity value, it is discharged from the polymerization vessel to turn it into a solid substance. At this time, in order to remove a small amount of titanium oxide agglomerates generated during polymerization, a filter can be installed at the bottom of the polymerization tank to remove the agglomerates, and this method is preferred. The filter used at this time is not particularly limited, and it is preferable to use a filter of 100 to 2000 mesh.

The limiting viscosity of the polyester resin composition thus obtained can usually reach the level of 0.4 to 0.9, and it is difficult to achieve the objective of the present invention when the limiting viscosity is higher than 0.9. The reason is that once the reaction temperature is increased in order to increase the limiting viscosity, thermal decomposition will occur, so the viscosity is often not increased. A preferred method for increasing the limiting viscosity to 0.9 or more can be a solid-phase polymerization method. If the solid phase polymerization method is used, the limiting viscosity can be increased to 2.0. To complete the polycondensation reaction, once the resulting polyester resin composition is cured, in the presence of an inert gas such as nitrogen or argon, or below 100 Torr, preferably below 10 Torr under reduced pressure, at a temperature of 170-220°C , Treat the resin composition in the form of slices, powders, fibers, plates, and blocks for 3 to 48 hours.

The polyester fiber of the present invention is a polyester fiber characterized by satisfying the following conditions (1) to (4) and having an intrinsic viscosity of 0.4 to 2. Under these conditions, fibers with proper matting, reduced friction coefficient, improved abrasion, and less thread breakage and fluff can be obtained.

(1) It should be composed of a polyester resin composed of 90% by weight or more of polytrimethylene terephthalate (2) It should contain 0.01 to 3% by weight of titanium oxide with an average particle size of 0.01 to 2 microns (3) Titanium oxide particles The longest part of the agglomerate formed by aggregation should be less than 12 fibers/mg fiber with a length of more than 5 microns. (4) The birefringence should be above 0.03.

The conditions (1) and (2) that must be satisfied by the polyester fiber of the present invention are the same as the content of the resin composition, so only the conditions (3) and (4) will be described below.

The length of the longest part of the agglomerate formed by the aggregation of titanium oxide particles exceeds 5 micrometers, in the polyester fiber of the present invention, must be less than 12/mg fiber. The number of such agglomerates is a value measured in accordance with the measurement method of titanium oxide agglomerates described in [2] in Examples. When the number of aggregates exceeds 12 per mg of fiber, the abrasion properties of the fiber are reduced, or thread breakage and fluffing are likely to occur. Of course, in this state, the spinning and extensibility are also low, and the spinning yield is also low. It is preferably 7 fibers/mg fiber or less, more preferably 3 fibers/mg fiber or less, and most preferably 1 fiber/mg fiber or less.

The birefringence of the polyester fiber of the present invention must be 0.03 or more. The birefringence is a parameter indicating the orientation of the polymer chains in the fiber in the axial direction of the fiber. When the birefringence is lower than 0.03, the polymer chain orientation of the obtained fiber is insufficient. Because the polymer chain exists in a state where it is easy to move, the friction coefficient of the fiber increases and the abrasion property of the fiber decreases, except that the purpose of the present invention cannot be achieved. In addition, even if stored near room temperature, the physical properties of the fiber will change over time. Even if a fabric is woven into a fabric in a state where such a structure is likely to occur, the dyeability and physical properties of the fabric will change in the storage state, so it becomes a fabric that is prone to staining and physical properties. In order to completely solve this problem, it is preferably 0.05 or more, and more preferably 0.06 or more. Moreover, in the range of 0.03 to 0.06, since the fiber orientation is insufficient, further stretching, or twisting or false twisting, can also provide processed yarns with bulkiness and tensile properties.

The form of the polyester fiber of the present invention may be a long fiber or a short fiber. In the case of long fibers, it can also be multifilament or monofilament, and it can also be processed into a non-woven fabric by spunbond method, micro mesh method, etc.

In addition, the polyester fiber of the present invention includes drawn yarns obtained by ordinary methods, straight drawn methods, high-speed spinning methods, etc., semi-drawn yarns (so-called POY) used in false twist processing, etc., and various processed yarns. Structures commonly used in synthetic fibers are also included.

The total fineness is not particularly limited, and it is in the range of 5 to 1000 d (denier), and is particularly preferably 5 to 200 d when used on clothing. The fineness of the monofilament is also not particularly limited, but is preferably 0.0001 to 10 d. Of course, when used in the form of multifilament, it can be 10-2000d. There are no particular restrictions on the cross-sectional shape of the fiber, and it may be circular, triangular, flat, star-shaped, W-shaped, etc., and may also be solid or hollow.

The physical properties of the polyester fiber of the present invention are explained below.

For example, in the case of drawn filaments, the strength varies with the limiting viscosity and the draw ratio, but it should be at least 2.5 g/d or more, usually 3.5 g/d or more. In particular, the most important feature of the present invention related to strength is that in order to reduce the number of agglomerates of titanium oxide particles and sufficiently improve the melt stability of the raw polymer, even if the limiting viscosity is increased, the molecular weight is unlikely to decrease in the melting stage, and high strength can be expressed. Therefore, for the polyester fiber of the present invention, the intrinsic viscosity is about 0.7 and is 4 g/d or more, and if the intrinsic viscosity is 1 g/d or more, the strength of 5 g/d can also be expressed. The elongation in this case is about 25 to 50%.

The elastic modulus of the fiber is a remarkable feature of the polyester fiber of the present invention, and shows an extremely low value of about 20-30 g/d. The so-called low modulus of elasticity means that this fabric exhibits an extremely soft feel. In addition, extremely excellent elastic recovery is also a notable feature of the fiber of the present invention. The polyester fiber of the present invention will show the following elastic recovery rate. Even if it is stretched about 15%, it can recover almost 100% of its original length. When stretched by 20%, it usually recovers more than 70% of its original length, and in some cases it exceeds 80%. Therefore, after the polyester fiber of the present invention is made into a fabric, it is possible to provide a product that not only has proper gloss and strength for different purposes, but also has a soft hand feel and has two extensibility. In addition, this kind of fiber will be a kind of titanium oxide with excellent dispersibility, low friction coefficient, prevention of hanging on the lead frame and roller, etc., good spinnability, agglomerates will not become defects, and abrasion. Good fiber.

The polyester fiber of the present invention can be produced by the known PTT spinning method described above for the polyester resin composition of the present invention. For example, it is particularly preferable to directly adopt the spinning method described in the published international patent application publications WO99/11845 and WO99/27168 filed by the inventors. That is, using an extruder or the like, the resin composition of the present invention that has been dried to a moisture content of at least 100 ppm or less, preferably 50 ppm or less, is melted, and then the resin composition is extruded through a spinneret and then wound, and then By stretching, the polyester fiber of the present invention can be obtained by this method. The stretching after winding mentioned here refers to the direct drawing method that directly connects the spinning and stretching processes, that is, the spinning is wound on a bobbin, etc., and the yarn is stretched by another device. The so-called ordinary method extrudes the resin composition through the spinneret. After it is completely cooled and solidified, it is wound on the first drum rotating at a certain speed for several times, so that there is no tension transmission before and after the drum. Stretching is performed between the second rollers after the first roller.

When the polyester fiber of the present invention is used alone or as a part of a fabric, it will form a fabric with excellent flexibility, stretchability and color development. When used as part of the fabric, there are no particular restrictions on other fibers other than the fiber of the present invention used. Especially when mixed with fibers such as drawn fibers, cellulose fibers, wool, silk, and acetate fibers, it can be found that the well-known synthetic fibers can be used. Features such as softness and stretchability that cannot be obtained with a blended fabric of fiber and chemical fiber. The cloth mentioned here refers to weaving and knitting.

The fabric of the present invention also includes the above-mentioned mixed fabric, and there are no particular restrictions on the form and weaving method of the polyester fiber used, and a known method can be adopted. For example, textiles such as plain weave fabrics and double-sided fabrics used for warp or weft yarns, tricot warp knitted fabrics, Russell ribbed fabrics and other knitted fabrics, etc. can also be used for other twisting, doubling and interweaving. Wait.

The fabrics of the present invention, including mixed fabrics, can be dyed, for example, after weaving, they can be scoured, pre-shaped, dyed with disperse dyes or cationic dyes, and finalized. And if necessary, after washing and before dyeing, the usual method can be used for alkali reduction treatment. Especially when cationic dyes are used, they must be copolymerized with sulfoisophthalate represented by 5-sulfoisophthalic acid, and the copolymerization ratio accounts for 1 to 3 mol% of the total carboxylic acid components, preferably Accounted for 1.5 to 2.5 mol%.

The washing can be carried out at 40 to 98°C. Especially when mixed with drawn fibers, the method of washing while relaxing treatment can further improve the elasticity, so it is more preferable.

Although one or two of the two heat setting before and after dyeing can be omitted, it is preferable not to omit both in order to improve the morphological stability and dyeability of the fabric. The heat setting temperature is 120 to 190°C, preferably 140 to 180°C; the heat setting time is 10 seconds to 5 minutes, preferably 20 seconds to 30 minutes.

Dyeing does not require a carrier and can be carried out at a temperature of 70 to 150°C, preferably 90 to 120°C, and particularly preferably 90 to 100°C. For uniform dyeing, it is particularly preferable to use acetic acid or sodium hydroxide to adjust the pH value corresponding to the dye, while using a dispersant composed of a surfactant.

After dyeing, soaping or reduction washing is carried out by a known method. Known methods can be used for these methods. For example, it can be treated with a reducing agent such as sodium bisulfite in an alkaline aqueous solution such as sodium carbonate and sodium hydroxide.

Best Mode for Carrying Out the Invention The following examples are given to illustrate the present invention in more detail, but the present invention is not limited by the examples at all. The main measurement values and evaluation values in the examples are all obtained by the following measurement methods or evaluation methods.

[1] Determination of the limiting viscosity The limiting viscosity [η] is based on an Ostwald viscosity tube, using o-chlorophenol at a temperature of 35°C, and comparing the specific viscosity ηsp with the concentration C (g/100 microliters). The ratio ηsp/C is extrapolated to the concentration 0, and it is calculated according to the following formula.

[η]=lim(ηsp/C)C0 [2] Determination of Titanium Oxide Aggregate 1 mg of resin composition or fiber is sandwiched between two 15mm×15mm cover glasses, and placed on a hot plate ( Melting point +20 ~ 30) °C temperature to melt it. After melting, apply a load of 100 grams on the cover glass to make the molten material overflow from between the cover glass, sticking and spreading between the two cover glass, and then put it into cold water to quench it. The rapid cooling can prevent the polymer from crystallizing, and it is easy to observe the dispersion state of titanium oxide. The same operation was performed five times to prepare five samples sandwiched between glass coverslips.

This sample was observed with an optical microscope, and the resin composition diffused between the cover glass sheets was magnified 200 times, and the resin composition diffused between the cover glass sheets was observed in the entire area. Titanium oxide agglomerates are larger than dispersed titanium oxide particles. The longest part of the titanium oxide agglomerates that can be found through a microscope is more than 5 microns in length as titanium oxide agglomerates, count the number, and convert it to unit weight. The resin combination used A considerable number of objects or fibers. The five prepared samples are all observed in the same way, and the average value is used as the number of aggregates (unit: unit/mg resin or unit/mg fiber).

[3] Determination of the amount of elemental phosphorus and the amount of elemental cobalt in the polyester resin composition or fiber The amount of elemental phosphorus and the amount of elemental cobalt are analyzed by high-frequency plasma emission spectroscopy (instrument: IRIS-AP type, --Produced by the company) method.

The analysis sample was prepared as follows: 0.5 g of resin composition or fiber and 15 ml of concentrated sulfuric acid were added to the Erlenmeyer flask, and heated and decomposed on a 150°C electric hot plate and 350°C electric hot plate for 3 and 2 hours, respectively. After cooling, add 5 ml of hydrogen peroxide, concentrate the solution to 5 ml after oxidative decomposition, add 5 ml of concentrated hydrochloric acid/water (1:1) aqueous solution, and then add 40 ml of water to make an analysis sample.

[4] Measurement of the average particle size of titanium oxide The average particle size of the raw material titanium oxide was obtained by dispersing titanium oxide in a 1 g/L sodium hexametaphosphate aqueous solution, and then using the laser diffraction-scattering particle size manufactured by Horiba Manufacturing Co., Ltd. Measured by a distribution measuring device (LA-920).

The average particle size of the titanium oxide in the resin composition or the fiber is the same as [2]. The titanium oxide particles dispersed in the polymer melted between the two cover sheets are observed under a microscope. The average length of the longest part is taken as the average particle size. In the case of the present invention, since the average particle size of the raw material titanium oxide and the average particle size in the polymer show approximately the same value, it can be measured by any method.

[5] The pressure rise model test of the spinneret assembly of the polyester resin composition, the polyester resin composition whose moisture content fell below 100 ppm after being melted by the extruder at 265°C, passed through the sand filter layer (filter area of 660 Square millimeter, thickness 2 cm), the particle size of the sand filter layer can pass 20 mesh but not 28 mesh filter; then it is sequentially passed through (1) 50 mesh filter with a filter area of 660 square millimeters, ( 2) 150 mesh filter with pore size, (3) 300 mesh filter with pore size, (4) sintered filter with 20 micron pore size (manufactured by American Filter Company, DYNALLOY X-7 type), (5) filter with pore size 50 mesh; then At a spinning speed of 25 g/min, let it pass through a spinneret with 12 micropores with a diameter of 0.23 mm into the atmosphere, and measure the pressure between the exit of the extruder and the sand filter layer at this time, that is, the self-spraying The pressure rise value from 5 hours after the silk start to 20 hours. In this case, if the pressure rise is below 40 kg/cm², even if the spinning is performed on an industrial scale, such a pressure rise in the spinneret will not pose a problem.

[6] Measurement of the amount of acrolein and allyl alcohol produced The resin composition or fiber was placed in a spherical furnace (manufactured by Mitsubishi Chemical Corporation, TOX-10 type chlorine-sulfur measuring device), and 50 liters at 130°C Air was passed through the sample at a flow rate of 24 hours for 24 hours, and the air passing through the sample was passed through the dry ice-acetone bath (the pipe was filled with polyoxymethylene) under the condition that it did not leak. The acrolein and allyl alcohol thus produced are captured in the tube. Then connect this tube to a heating and desorption device (manufactured by Shimadzu Corporation, FLS-1 type), and heat it from -30°C to 200°C to vaporize acrolein and allyl alcohol in the tube and pass it to the GC/MS (An instrument connected by a gas chromatograph and a mass spectrometer, manufactured by Shimadzu Corporation, model QP-5000, column: DB624, 60 meters), heating from 40°C to 200°C at a heating rate of 10°C/min Measured during the process to find the amount of acrolein and allyl alcohol captured. This amount indicates the amount of acrolein and allyl alcohol (expressed in ppm based on the resin composition used) that would be generated by heating at 130°C for 24 hours in the air when 1 gram of resin composition or fiber is used.

[7] Evaluation method of resin composition spinnability (measurement of fluffing rate) The polyester resin composition dried to a moisture content of 50 ppm or less was melted at an extrusion temperature of 270°C and passed through a spinneret hole (36 holes) , Diameter 0.23 mm), composed of 52% by weight isooctyl stearate, 27% by weight oleyl ether, 11% by weight of sodium alkyl sulfonate with 15 and 16 carbon atoms, and 10% by weight of Redwood viscosity of 130 seconds The oil agent composed of the liquid paraffin attached is equivalent to 0.4-0.7% by weight of the fiber weight, and is melt-spinned at a spinning speed of 1600 m/min, and then stretched on a hot roller at 55°C and a hot plate at 140°C. The fineness and the number of filaments of the obtained fiber were set to 50d/36f. Take out 1000 500g weft yarn tubes, count the number of exposed surface fluffs, divide the value by 1000 and multiply by 100, and use it as the fluff rate.

[8] Measurement of fiber mechanical properties (strength, elongation, and elastic modulus) were measured in accordance with JIS-L-1013.

[9] The birefringence was measured in accordance with the description on page 969 of the "Fiber Handbook" raw materials (fifth printing, published by Maruzen Co., Ltd.), using an optical microscope and an optical compensator to observe the fiber surface, and the observed hysteresis Find the birefringence.

[10] Determination of elastic recovery rate The fiber is mounted on a tensile tester with a distance of 20 cm between the chucks, stretched at a speed of 20 cm/min until the elongation rate reaches 20%, and left for 1 minute under elongation. . Then shrink it at the same speed and draw a stress-deformation curve. The residual elongation (A) is taken as the elongation when the stress is zero during the fiber shrinkage. Obtain the elastic recovery rate according to the following formula.

Elastic recovery rate (%)=[(20-A)/20]×100[11] Measurement of coefficient of friction Here, the coefficient of dynamic friction between the filament and the metal is calculated. Under the following conditions, the measurement was carried out using a dynamic friction coefficient (μ) tester manufactured by Koiseki Co., Ltd. Apply a tension of 4 g/d to the fiber on an iron cylinder with a diameter of 25 mm as a friction body and a mirror-finished surface, and set the direction of entering the friction body and the direction of exiting the friction body to 90 degrees. The friction is generated at a speed of 100 m/min at 25°C and 65% relative humidity, and the coefficient of dynamic friction μ at this time is calculated according to the following formula.

μ=(360×2.3026/2πθ)×log10(T2/T1) In the formula, T1: the tension on the entry side of the friction body (equivalent to 0.4 grams of tension per denier) T2: the tension on the exit side of the friction body π: the ratio of circumference θ :90 degrees.

[12] Measurement of the number of yarn friction broken threads The number of yarn friction broken threads is expressed by the number of times the fibers rub against each other until thread breakage occurs. The purpose is to show how easy the fibers are to wear. In other words, the more the number of times, the better the wearability (the harder it is to wear).

The frictional bond strength tester (No. 890) manufactured by Toyo Seiki Seisakusho Co., Ltd. was used to measure the number of yarn frictional breaks. Connect both ends of the yarn through a pulley with a metal clip. This metal clip can reciprocate within a stroke of 20 millimeters in length. Rotate the pulley, twist twice, apply a load of 50 grams, and make the clip reciprocate at 150 strokes/min. A counter can be used to measure the number of reciprocating motions, and calculate the number of times until the yarn breaks as the number of yarn friction breaks.

Reference Example 1 The titanium oxide dispersion used in the following examples was prepared according to the following description.

Method (1): Add 20% by weight of anatase-type titanium oxide with an average particle size of 0.5 microns to 1,3-propanediol, and stir for 10 hours at 1000 rpm.

Method (2): Add 21% by weight of anatase-type titanium oxide with an average particle size of 0.5 microns to 1,3-propanediol, and stir for 10 hours at 1000 rpm. Then centrifugation was performed at 6000 rpm for 10 minutes, and the supernatant was separated. The content of titanium oxide in the treatment liquid was 20% by weight. Observing the titanium oxide removed by centrifugal separation with an optical microscope, it was found that there were aggregates of titanium oxide particles with the longest part longer than 5 microns.

Method (3): Add 21% by weight of anatase titanium oxide with an average particle size of 0.5 microns to 1,3-propanediol, and stir for 10 hours at 1000 rpm. Then pass through a 500 mesh filter three times. The content of titanium oxide in the treatment liquid was 20% by weight. Observing the titanium oxide removed by centrifugal separation with an optical microscope, it was found that there were aggregates of titanium oxide particles with the longest part longer than 5 microns.

Method (4): Add 21% by weight of anatase-type titanium oxide with an average particle size of 0.5 microns to 1,3-propanediol, and stir for 10 hours at 1000 rpm. Then, it was passed through a 500-mesh filter once, and then centrifuged at 6000 rpm for 25 minutes to separate the supernatant. The content of titanium oxide in the treatment liquid was 20% by weight. Observing the titanium oxide removed by centrifugal separation with an optical microscope, it was found that there were aggregates of titanium oxide particles with the longest part of the length exceeding 5 microns.

In Examples 1-8, 1,300 parts by weight of terephthalic acid (hereinafter abbreviated as TPA) and 1,369 parts by weight of 1,3-propanediol were mixed, and esterified under normal pressure and at a heating temperature of 240°C. Add tetrabutoxide titanium (0.1% by weight/TPA, this unit represents the weight ratio relative to TPA), the phosphorus compounds and/or hindered phenolic antioxidants shown in Table 1, and the antioxidants shown in Table 1 in sequence within 5 minutes The titanium oxide dispersion obtained by the methods (2) to (4) in Reference Example 1 was polycondensed at 270° C. and a pressure of 0.2 Torr for 2.5 hours. The phosphorus compound and/or hindered phenol antioxidant are added to the polymerization system in the form of a 2% by weight 1,3-propanediol solution. The weight% of the phosphorus compound, hindered phenolic antioxidant, and titanium oxide dispersion in the table all represent the weight% in the finally obtained resin composition. The resin composition having an intrinsic viscosity of 0.68 thus obtained was pulled out in a rope shape in water, and then cut into slices. Furthermore, after performing solid phase polymerization at 215°C for 5 to 7 hours in a nitrogen atmosphere, a polyester composition was obtained. The average particle diameter of the titanium oxide particles in the obtained resin composition was 0.5 μm.

Using the resin composition thus obtained, a drawn yarn was obtained by the spinning method of (7). The properties of the fibers are shown in Table 2. In the tests of Examples 1-8, PTT fibers with less agglomerates of titanium oxide particles, a small friction coefficient, a low fluff rate and good quality can be obtained. In these examples, the production amounts of acrolein and allyl alcohol were both at a low level. Moreover, the number of friction cuts of the yarns in Examples 1 and 5 were 431 and 453, respectively. The average particle size of the titanium oxide particles in the obtained fiber is 0.5 microns.

In Comparative Example 1, the operation of Example 1 was repeated except that the phosphorus compound and hindered phenolic antioxidant were not added, and the titanium oxide dispersion obtained by the method (1) in Reference Example 1 was added.

The obtained resin composition contained a large amount of agglomerates, so the pressure rise of the spinneret assembly showed a value as high as 52 kg/cm², and the fluff rate was also large. The deterioration of the friction coefficient is also the cause of the decrease in the fuzz rate. In addition, the amount of powder generated when rubbing this sheet material is also larger than that of the sheet material of Example 1.

Moreover, the number of yarn friction breaks was as low as 76 times.

In Comparative Example 2, the operation of Example 1 was repeated except that 0.05% by weight of trimethyl phosphate and no titanium oxide were added, and the titanium oxide dispersion obtained by the method (1) in Reference Example 1 was added.

The obtained resin composition does not contain titanium oxide, although the pressure rise of the spinneret assembly shows a value as low as 9 kg/cm²; however, the friction coefficient is high, and the heating roller pulls the fiber during stretching, resulting in an increase in the fuzzing rate. Big. In addition, the obtained fiber is too shiny and gives a tacky feel.

In Comparative Example 3, a dispersion liquid prepared by dispersing the titanium oxide used in Example 1 with the method (2) of PET without titanium oxide and an intrinsic viscosity of 0.72 in ethylene glycol was polymerized, and the obtained content was 0.5% by weight Titanium oxide, 50d/36F PET fiber with an intrinsic viscosity of 0.72, and the measured values of friction coefficient are 1.967 and 1.934, respectively. In this case, an oil agent composed of 30% oleyl oleate, 35 wt% hexyl stearate, 30 wt% emulsifier and 5 wt% antistatic agent is attached to the fiber. Moreover, the number of yarn friction breakages totaled more than 2000 times.

In addition, the dispersion liquid formed by dispersing titanium oxide in ethylene glycol in Example 1 was polymerized by the method of (1) to prepare a 50d/36F PET fiber containing 0.5% by weight of titanium oxide and an intrinsic viscosity of 0.72. The friction coefficient The measured values were 1.967 and 1.934, respectively. As the oil agent, the above-mentioned oil agent is used. The number of aggregates in this fiber is 16 per milligram of fiber, the friction coefficient is 1.936, and the number of yarn friction breaks is more than 2000 times.

Although PET fiber has a similar structure to PTT fiber, it is very different from PTT fiber, and the agglomerate has a slight influence on the coefficient of friction and abrasion.

Example 9 Added 25,000 parts by weight of dimethyl terephthalate (hereinafter referred to as DMT), 21553 parts by weight of 1,3-propanediol, and 0.1% by weight/DMT of the theoretical polymer amount (this unit represents the weight ratio to DMT) The 7:1 mixture of calcium acetate and cobalt acetate tetrahydrate used as a transesterification catalyst was subjected to transesterification reaction at 50°C for 3 hours. Then, 0.1% by weight/DMT of trimethyl phosphate is added, and then the titanium oxide dispersion prepared by the method (4) is added to make the titanium oxide content reach 0.4% by weight. The polymerization reaction was carried out under a vacuum of 0.1 Torr at 275°C for 3 hours to obtain a polyester resin composition with an intrinsic viscosity of 0.75 and excellent whiteness. The elemental phosphorus content is 180ppm, and the elemental cobalt content is 20ppm.

The fiber obtained by the spinning method in the resin spinning evaluation method described in (7) above, wherein the number of titanium oxide aggregates is 1 per mg fiber, the spinneret assembly pressure rises to 12 kg/cm², and the friction coefficient It is low, so it is possible to obtain PTT fiber with low raising rate and good quality. The content of elemental phosphorus in the fiber is 175ppm, and the content of elemental cobalt is 15ppm. Moreover, the amount of acrolein and allyl alcohol is also at a low level. In addition, the average particle size of titanium oxide in the fiber was 0.5 microns, and the PTT content was 99% by weight.

Table 1 Composition and properties of raw materials (polyester resin composition)

Note: PTT: Polytrimethylene terephthalate Irg1010: Pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (-Hindered phenol produced by Chemical Company Antioxidant)

Table 2 Polyester fiber and its properties

Note: PTT: Polytrimethylene terephthalate Irg1010: Pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (-Hindered phenol produced by Chemical Company Antioxidant)

Example 10 Added 25,000 parts by weight of dimethyl terephthalate (hereinafter referred to as DMT), 500 parts by weight of dimethyl 5-sulfoisophthalate sodium salt, 21553 parts by weight of 1,3-propanediol, and theoretical polymerization A 7:1 mixture of calcium acetate and cobalt acetate tetrahydrate used as a transesterification catalyst of 0.1% by weight/DMT (this unit represents the weight ratio to DMT) of the substance amount was subjected to transesterification reaction at 50°C for 3 hours. Then, 0.1% by weight/DMT of trimethyl phosphate is added, and then the titanium oxide dispersion prepared by the method (4) is added to make the titanium oxide content reach 0.04% by weight. The polymerization reaction was carried out under a vacuum of 0.1 Torr and 275°C for 3 hours to obtain a polyester resin composition with an intrinsic viscosity of 0.68 and excellent whiteness, in which the number of titanium oxide aggregates of 96.5% by weight of PTT was 2 per mg of resin. The elemental phosphorus content is 171ppm, and the elemental cobalt content is 18ppm. The average particle size of titanium oxide in the resin composition is 0.5 microns, and the PTT content is 97.5% by weight.

In the fiber obtained by the spinning method in the resin spinning evaluation method of (7), the number of titanium oxide aggregates is 1/mg fiber, the pressure of the spinneret assembly rises to 15 kg/cm², and the friction coefficient is also As low as 1.563, it is possible to obtain PTT fibers with a fluff rate as low as 0.2, good quality, and a birefringence of 0.075. In addition, the amount of acrolein and allyl alcohol are as low as 3.3 and 5.8 ppm, respectively. The content of elemental phosphorus in the fiber is 164ppm, and the content of elemental cobalt is 15ppm. In addition, the average particle size of titanium oxide in the fiber was 0.5 microns, and the PTT content was 97.4% by weight.

Example 11 Under the conditions of Example 4, cobalt acetate was added at a ratio of 0.005% by weight/TPA at the beginning of the polymerization, and the test was repeated. The elemental cobalt content is 8ppm. The number of titanium oxide agglomerates is 0.5 per mg of resin, the pressure rise is 10 kg/cm², and the raising rate is 0. The average particle size of titanium oxide in the resin composition is 0.5 micrometers. In addition, the PTT content in the resin composition is 99% by weight.

Using the spinning method in the resin spinning evaluation method of (7), a PTT fiber having a birefringence of 0.075, a cobalt content of 5 ppm, and a titanium oxide aggregate of 0.1 mg/fiber can be obtained. Moreover, the amount of acrolein and allyl alcohol was as low as 3.1 and 5.7 ppm, respectively. The average particle size of titanium oxide in the fiber is 0.5 microns. The PTT content in the resin composition is 99% by weight.

Example 12

The polyester fiber obtained in Example 9 and 210 denier polyurethane-based drawn fiber Roika (manufactured by Asahi Kasei Kogyo Co., Ltd.) were used to prepare a warp knitted fabric. In this case, the settings are as follows, needle size (-) 28G, loop (-) length: polyester fiber 1080 mm/480 stroke (-), drawn fiber 112 mm/480 stroke, picking The density is 90 strokes/inch. The blending ratio of polyester fiber is set at 75.5%.

The obtained grey fabric was subjected to a relaxation washing treatment at 90°C for 2 minutes, and dry heat setting at 160°C for 1 minute. In the presence of 8% owf disperse dye Dianix Black BG-FS (manufactured by Diesta Japan Co., Ltd.) and 0.5 g/L of the dyeing aid Nikakansolto 1200, the pH is adjusted to 6 with acetic acid, and the bath ratio is 1:30 and 110 Dyeing at °C for 60 minutes.

The resulting fabric is soft and stretchable, has appropriate gloss, and has a unique texture that cannot be obtained with conventional PET fibers and nylon fibers.

In Example 13, the polyester fiber prepared in Example 10 and 210 denier polyurethane-based drawn fiber Roika (manufactured by Asahi Kasei Kogyo Co., Ltd.) were used to prepare a warp knitted fabric. In this case, the settings are as follows, needle size (-) 28G, loop (-) length: polyester fiber 1080 mm/480 stroke (-), drawn fiber 112 mm/480 stroke, picking The density is 90 strokes/inch. The blending ratio of polyester fiber is set at 75.5%.

The obtained grey fabric was subjected to relaxation treatment and washing at 90°C for 2 minutes, and dry heat setting at 160°C for 1 minute. Using cationic dye Kadakuriru black BS-ED (manufactured by Nippon Kayaku Co., Ltd.) and 1 g/l dispersant Diipa-TL (manufactured by Meisei Chemical Co., Ltd.), add 50 g/l sodium sulfate and 15 g/l sodium carbonate, In the aqueous solution adjusted to pH 11, the dye concentration is 2% owf, and dyeing is performed at a bath ratio of 1:50 and a temperature of 110°C for 1 hour. After dyeing, it was saponified with 1 g/liter Ceran Ape P (manufactured by Sanyo Chemical Industry Co., Ltd.) at a bath ratio of 1:50 and 80°C for 10 minutes. After dyeing, use the usual method for finishing.

The fabric obtained is soft and stretchable, has appropriate gloss, is excellent in sharpness, and has a unique texture that cannot be obtained with conventional PET fibers and nylon fibers.

Industrial Applicability. Titanium oxide is highly dispersed in the polyester resin composition based on the PTT of the present invention. It is used in the melt spinning method because the pressure of the spinneret assembly rises and the spinning is stable, so it can provide -A kind of PTT fiber with proper gloss and moderate matting. The fiber's fiber strength and abrasion properties are very little reduced due to the titanium oxide aggregates, and the friction coefficient is also reduced. Therefore, when the fiber contacts the drum and the lead frame during the spinning and processing stage, the friction of the fiber can be reduced, which can provide a smooth Spinning and processing fibers.

Although the titanium oxide-containing PTT resin composition of the present invention contains titanium oxide, since chips and the like can inhibit the generation of acrolein and allyl alcohol in the drying process before the spinning process, a resin with excellent whiteness can be obtained Composition and fiber.

The polyester fiber of the present invention can be used as clothing materials for underwear, sportswear, pantyhose, lining and raincoats, and can also be used for making carpets, cushions, flocking, fishing line, artificial grass, ropes, and fabric backings. , Umbrellas, tents and other daily necessities fiber materials. The resin composition of the present invention can also be used in the form of films and molded products.