467results about "Monocomponent copolyesters artificial filament" patented technology

A moisture-absorbing and sweat-releasing polyester fiber and a preparation method therefor. A three-stage side-blown cooling process is used for cooling in the method, wherein in the first stage, the air speed is 0.45-0.60 m / s, and the cooling length is 10-40 cm; in the second stage, the air speed is 0.60-0.75 m / s, and the cooling length is 40-50 cm; and in the third stage, the air speed is 0.75-0.90 m / s, and the cooling length is 50-120 cm. The moisture-absorbing and sweat-releasing polyester fiber has a fineness of 500-965 dtex, a breaking strength of greater than or equal to 2.0 cN / dtex, a coefficient of variation (CV) of the breaking strength of less than or equal to 4.0%, an elongation at break of 128±3.0%, a CV of the elongation at break of less than or equal to 4.0%, a CV of yarn unevenness of less than or equal to 1.80%, and a degree of profile of greater than or equal to 44%. The method realizes uniform cooling, and the prepared moisture-absorbing and sweat-releasing polyester fiber has good quality.

The invention relates to a chenille waterproof floor mat and a production process thereof, a base cloth used by the chenille waterproof floor mat is modified, namely polyacrylic acid is used as an adhesive, antibacterial water-absorbing microspheres are arranged into the base cloth to prepare the modified base cloth, and the antibacterial water-absorbing microspheres have good water-absorbing performance and antibacterial performance, so that the antibacterial water-absorbing microspheres have good water-absorbing performance and antibacterial performance. The chenille waterproof floor mat can rapidly absorb water and maintain the antibacterial performance in the using process, modified polyester is prepared and used as a raw material to prepare modified polyester filaments, then the modified polyester filaments serve as decorative yarn of chenille yarn, and due to the fact that the modified polyester contains zwitter-ion side chains, the antibacterial performance of the chenille waterproof floor mat is improved, and the antibacterial performance of the chenille waterproof floor mat is improved. The chenille yarn has the anti-fouling and anti-bacterial performance, the hydrophilic performance of the chenille yarn is improved, and then the chenille waterproof floor mat has the good water-absorbing, anti-bacterial and anti-fouling performance.

The invention belongs to the technical field of high polymer materials, and particularly relates to spinning-grade all-aryl polynaphthyl ester resin and a preparation method thereof. According to the invention, p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, aromatic dicarboxylic acid and ethylene glycol monomer are adopted as raw materials, polymerization reaction is carried out under the action of the catalyst, spinning-grade all-aryl polynaphthyl ester resin is successfully obtained under specific reaction conditions, and the spinning-grade all-aryl polynaphthyl ester resin has high molecular weight, low impurity content and good heat resistance, and can be used for preparing the spinning-grade all-aryl polynaphthyl ester resin. The melt fluidity is good, the shear thinning phenomenon is more obvious, and the method can be directly used for preparing the polynaphthalene ester fiber.

The invention discloses an antibacterial and deodorant blended fabric, a preparation method thereof and application of the antibacterial and deodorant blended fabric in underwear, and relates to the technical field of fabrics. When the antibacterial and deodorant blended fabric is prepared, firstly, indolyl polyester is subjected to melt spinning to be prepared into fibers; the preparation method comprises the following steps: reacting fibers, indole and indole-6-formaldehyde, reacting with 4-(aminomethyl)-2, 6-di-tert-butylphenol, and reducing to obtain modified polyester fibers; secondly, the pretreated bamboo fibers react with carbon disulfide and potassium hydroxide; the preparation method comprises the following steps: oxidizing a modified bamboo fiber precursor obtained by reacting the modified bamboo fiber with 1-(2-propenyl)-1, 3, 5-triazine-2, 4, 6 (1H, 3H, 5H)-triketone to obtain a modified bamboo fiber, and oxidizing the modified bamboo fiber precursor to obtain the modified bamboo fiber; the modified polyester fibers and the modified bamboo fibers are blended and woven to obtain fabric, and then the fabric is finished through a finishing agent to obtain the antibacterial and deodorant blended fabric. The antibacterial and deodorant blended fabric prepared by the invention has good antistatic, antibacterial and durable properties.

The invention belongs to the technical field of regenerated polyester fibers, and particularly relates to a preparation method of low-temperature easy-to-dye regenerated polyester fibers, which specifically comprises the following steps: firstly, carrying out transesterification on waste polylactic acid and aliphatic dibasic acid to obtain a double-carboxyl-terminated polylactic acid oligomer; sequentially carrying out homogenization reaction and condensation polymerization reaction on the double-end carboxyl polylactic acid oligomer and polyether diamine to obtain modified polylactic acid, and spinning the modified polylactic acid to obtain the low-temperature easy-to-dye regenerated polyester fiber. Wherein the number of carbon atoms of the aliphatic dibasic acid is 4-20, the number-average molecular weight # imgabs0 # of the double-end carboxyl polylactic acid oligomer is 2000-12000 g / mol, and the number-average molecular weight of the polyether diamine is 600-4000 g / mol; the low-temperature easy-to-dye regenerated polyester fiber prepared by the method is high in mechanical strength, can be dyed by adopting disperse dye at 80-100 DEG C, has the dye uptake of 95% or above, and is good in color fastness.

A method for preparing a cationic dyeable flame-retardant high-strength polyester fiber is provided, after mixing oligomer A, oligomer B, and ethylene terephthalate and carrying out a polycondensation reaction to obtain a cationic dyeable flame-retardant polyester masterbatch, adding the cationic dyeable flame-retardant polyester masterbatch to the polyester chips according to a certain ratio for melt spinning, to prepare the cationic dyeable flame-retardant high-strength polyester fiber; oligomer A is prepared by the esterification reaction of a phosphorus flame retardant and a diol; oligomer B is prepared by the esterification reaction of sodium isophthalate sulfonate and a diol; the ratio of the sum of the molar weight of oligomer A and oligomer B to the molar weight of ethylene terephthalate is 3:7-6:4. The preparation method is simple, and the cationic dyeable flame-retardant high-strength polyester fiber has excellent mechanical properties, and can be used in automobiles, ships, and the interior decoration of high-class hotels.

The invention provides a superfine denier profiled polyester staple fiber and a preparation method thereof.The preparation method includes the steps of raw material pretreatment, melt spinning, nascent filament treatment, heat setting and curling, oiling and cutting off and the like, polyester chips have high intrinsic viscosity and melting point, and under the action of six-zone temperature control, a high-hole-density spinneret plate and a high draft multiple, the polyester chips are subjected to melt spinning, so that the polyester chips are prepared into the superfine denier profiled polyester staple fiber. The superfine, special-shaped and hollow polyester staple fibers are prepared. The obtained polyester staple fiber has good breaking strength, rebound resilience and a low-defect structure, the bulkiness, flexibility and structural consistency of the fiber are remarkably improved, the environment and process limitation of a traditional sea-island fiber alkali stripping method is broken through, and the polyester staple fiber is suitable for the fields of high-end filling, plush imitation, non-woven materials and the like.

The present invention provides a system and a method for preparing a polyester polyol prepolymer. The system comprises an atmospheric pressure bubbling reaction rectifying tower and a reduced pressure heating reaction rectifying tower. The method comprises: introducing a protective gas into an atmospheric pressure bubbling reaction rectifying tower, introducing a raw material for preparing a polyester polyol prepolymer into the atmospheric pressure bubbling reaction rectifying tower, and carrying out a primary esterification reaction or an ester exchange reaction; and introducing the primary esterification product or the ester exchange product into a reduced pressure heating reaction rectifying tower, and carrying out one or more of a deep esterification reaction, an ester exchange reaction, and a pre-polycondensation reaction to obtain the polyester polyol prepolymer. The present invention has the advantages of high reaction efficiency, stable product quality, easiness in product separation, convenience in large-scale production and the like.

A method for preparing direct melt-spun high-viscosity PBAT / low-viscosity PET two-component elastic fiber and a high-viscosity PBAT polymerization reactor. This method uses two production lines respectively used to produce a high-viscosity PBT melt and a low-viscosity PET melt, which are then spun. The high-viscosity PBAT production line comprises a first esterification reactor, a second esterification reactor, a first prepolymerization reactor, a second prepolymerization reactor, and a high-viscosity PBAT polymerization reactor. The polymerization reactor is designed with a special disc structure in a parallel two-shaft disc reactor, and the two shafts are rotated in opposite directions, improving the devolatilization effect and self-cleaning, significantly increasing the viscosity. By using this method, the cost is low and the production capacity is high, the process flow is shortened, the fiber strength can reach 2.55˜2.85 cN / dtex, the crimp shrinkage rate can reach 25%˜60%, and the crimp stability can reach 58%˜70%.

The invention relates to the technical field of polyester fibers, in particular to a preparation method of flame-retardant ultrahigh-elasticity polyester FDY (fully drawn yarn) fibers, which comprises the following steps: S1, esterification: uniformly mixing terephthalic acid and ethylene glycol, adding the mixture into an esterification kettle, and carrying out esterification reaction to obtain an esterification product; s2-1, pre-polycondensation: adding the esterification product, Sb2O3 and a flame retardant into a pre-polycondensation kettle, and carrying out pre-polycondensation reaction to obtain a pre-polycondensation product; s2-2, final polycondensation: adding the pre-polycondensation product into a final polycondensation kettle to carry out final polycondensation reaction to obtain a PBT melt; s3, spinning: sequentially metering the PBT melt, spinning with a spinneret plate, cooling, oiling, stretching, sizing and winding to obtain the FDY fiber. According to the preparation method disclosed by the invention, the flame retardant and PET are copolymerized, so that the flame retardant property of the PET fiber is improved, smoke and harmful gas are less when the PET fiber is combusted, the PET fiber is more environment-friendly to use, and the manufacturing cost of the flame retardant is lower.

Provided is a liquid crystalline polyester fiber capable of achieving improved weatherability without kneading a UV absorber into the fiber or attaching a weatherable UV absorber after fiber spinning. The liquid crystalline polyester is a fiber that consists essentially only of a liquid crystalline polyester, in which the amount of UV absorber used is 5 mass % or less, and the strength retention in the weather fastness test with xenon arc lamp light in accordance with JIS L 0891 is 60% or more.

The present invention discloses an aliphatic-aromatic polyester composition, polyester fiber, and its preparation and use. The aliphatic-aromatic polyester composition of the present invention comprises: i) an aliphatic-aromatic polyester based on an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid, and an aliphatic dihydroxy compound; and ii) a titanium element content of 55 to 88 ppm, based on the weight of the aliphatic-aromatic polyester composition. The aliphatic-aromatic polyester composition has an acid value of 0.84 mg KOH / g or less according to standard DIN EN 12634-1998. The aliphatic-aromatic polyester composition of the present invention not only has a low yellowness index and good colorability, but also effectively improves hydrolysis resistance, making it suitable for wide use in the field of polyester fibers.

The invention relates to a preparation method of modified regenerated polyester fibers, and belongs to the technical field of textile materials. The modified regenerated polyester fiber is prepared by taking waste polyester fiber, ethylene glycol, a catalyst, a flame-retardant bacteriostatic agent, a polycondensation catalyst antimony trioxide, a heat stabilizer trimethyl phosphate and a delustering agent titanium dioxide as raw materials. The preparation method comprises the following steps: firstly, decomposing the waste polyester fiber into small molecules by using ethylene glycol to obtain an alcoholysis product; according to the preparation method, waste polyester fibers are selected as raw materials, so that the preparation method is green and environment-friendly, a flame-retardant bacteriostatic agent and ethylene glycol are polymerized, an alcoholysis product, antimony trioxide, trimethyl phosphate and titanium dioxide are added into a polymerization product, modified PET is obtained through a condensation polymerization reaction, and finally, the modified PET is subjected to melt extrusion and spinning to obtain the modified regenerated polyester fibers. The prepared modified regenerated polyester fiber has good flame retardance and antibacterial activity, and can be widely applied to the field of clothing and home textiles.

The invention relates to the field of polyester fiber production, and discloses modified copolyester, a preparation method thereof and a polyester fiber product. The modified copolyester contains a structural unit A as shown in a formula (I), a structural unit B as shown in a formula (II) and a structural unit C as shown in a formula (III), wherein R1, R2, R3 and R4 are each independently a C1-C10 alkyl group, and m is a positive integer greater than 3; rI, RII, and RIII are each independently hydrogen or a C1-C10 alkyl group. The preparation method comprises the following step: in the presence of a catalyst, carrying out contact reaction on a binary acid monomer, a dihydric alcohol monomer, a component a with a structure as shown in a formula (I), a component b with a structure as shown in a formula (II) and a component c with a structure as shown in a formula (III). The modified copolyester fiber material has good softness and crease resistance, the wearability of a polyester fiber product can be effectively improved, and the diversity and functionality of the polyester material are improved. # imgabs0 #

The invention relates to the technical field of polymer dye synthesis, and discloses a monomer for a blue polyester fiber and a preparation method thereof.According to the monomer for the blue polyester fiber, 1, 4-arylamino substituted anthraquinone serves as a color development mother nucleus, a benzoate group is introduced to aryl of the 1, 4-arylamino substituted anthraquinone mother nucleus, and the monomer for the blue polyester fiber is obtained; the benzoate group is connected with the chromophoric parent nucleus through a carbon-carbon bond; the molecular terminal of the monomer for the blue polyester fiber is connected with an exposed ester group through an aryl group, and the exposed ester group is used for transesterification with dihydric alcohol under the melt polycondensation condition of polyester. The novel monomer for the blue polyester fiber, provided by the invention, has excellent color development performance and thermal stability, can be directly used for in-situ synthesis of blue polyester and can be directly used for melt spinning, and the color fastness and coloring uniformity of a product are improved; meanwhile, the monomer for the blue polyester fiber, provided by the invention, is simple in preparation method, low in cost and easy for large-scale production.

The present invention provides a biodegradable resin composition and a biodegradable molded article including the same, wherein the biodegradable resin composition includes: a first biodegradable resin including a first repeating unit derived from a diol, a second repeating unit derived from aromatic dicarboxylic acid, and a third repeating unit derived from aliphatic dicarboxylic acid; and a crystallization accelerator, wherein the crystallization accelerator is included in a content of 100 ppm to 50,000 ppm, and an isothermal crystallization time at 90° C. according to Measurement Method 1 (see the detailed description) is 10 seconds to 900 seconds.

The present invention relates to a biodegradable resin composition and a biodegradable nonwoven fabric including the same, and more particularly, the biodegradable resin composition includes a biodegradable resin including a first repeating unit derived from a diol having 2 to 4 carbon atoms and a second repeating unit derived from an aliphatic dicarboxylic acid having 2 to 6 carbon atoms; and an inorganic nucleating agent, wherein the biodegradable resin composition has a crystallinity of 15% to 50% as measured using differential scanning calorimetry.

The invention discloses a moisture-absorbing and sweat-releasing polyester-spandex blended antibacterial fabric, a preparation method thereof and application of the fabric in underwear, and relates to the technical field of fabrics. When the moisture absorption and sweat releasing polyester and ammonia blended antibacterial fabric is prepared, firstly, phosphorus-containing polyester and dinitrobenzyl pyridine react to obtain modified polyester, the polyester is prepared into fibers through melt spinning, and then reduction is conducted; secondly, enabling thiophene-3-alcohol to react with the polyurethane prepolymer, preparing fibers through a dry spinning process, and enabling the fibers to react with thiophene and 3-aminothiophene to obtain modified polyurethane fibers; finally, the modified polyester fibers and the modified polyurethane fibers are blended into yarn, the yarn reacts with toluene diisocynate and then reacts with isophorone diisocyanate to obtain modified yarn, the modified yarn is woven into fabric, and the moisture absorption and sweat releasing polyester and polyurethane blended antibacterial fabric is obtained. The moisture-absorbing and sweat-releasing polyester-spandex blended antibacterial fabric prepared by the invention has good antibacterial property, antistatic property and mechanical property.

Embodiments of the present invention provide an eco-friendly biodegradable resin composition that includes a first biodegradable resin including diol, aromatic dicarboxylic acid and aliphatic dicarboxylic acid and has a melt index change value of 45 g / 10 min or less according to the disclosed measurement methods, a method of preparing the biodegradable resin composition, and a biodegradable molded article manufactured by the method. Embodiments of the present invention provide a method of manufacturing an eco-friendly biodegradable nonwoven fabric, the method including spinning a biodegradable resin composition to manufacture biodegradable yarns; cooling the biodegradable yarns; and combining the cooled biodegradable yarns to form a biodegradable yarn web, wherein the biodegradable resin composition includes a first biodegradable resin, the first biodegradable resin includes diol, aromatic dicarboxylic acid and aliphatic dicarboxylic acid, and the biodegradable resin composition has a crystallization temperature of 70 °C to 130 °C,; a biodegradable yarn; and a biodegradable nonwoven fabric including the biodegradable yarn.

The method for producing recycled polyethylene terephthalate yarn according to the present invention includes the steps of melting recycled polyethylene terephthalate chips and spinning them through a spinning nozzle to produce a spun yarn, and multi-stage drawing and winding the spun yarn using equipment with five or more stages of drawing godet rollers, wherein the recycled polyethylene terephthalate chips contain 1.0 mol% or less of isophthalic acid, the draw ratio is 1.5 to 2.45, and the speed of the fourth godet roller among the five or more stages of drawing godet rollers is 5500 m / min to 7000 m / min. The recycled polyethylene terephthalate yarn produced by this method has a strength of 8.5 g / d or more and a dimensional stability ES of 11.0% or less.

This invention relates to the field of yarn technology, specifically disclosing a superconducting wet-drying yarn, its preparation method, and its application. The yarn is prepared by blending high-shrinkage polyester fibers and cotton fibers. The preparation of the high-shrinkage polyester fibers includes two parts: raw material synthesis and fiber forming. Terephthalic acid and ethylene glycol are used as raw materials. After the esterification reaction, polyethylene glycol and aromatic dicarboxylic acid ester sulfonate are added, resulting in high-shrinkage polyester chips. These chips are then used as raw materials for spinning to obtain high-shrinkage polyester fibers. Through the two-component design of the yarn, a micro-circulation diffusion system with superconducting moisture absorption and sweat-wicking effect is formed, effectively improving the hygroscopicity of the polyester fibers. Even after multiple washes, it still possesses excellent superconducting wet-drying properties, long-lasting efficacy, and good wash resistance, without causing uneven dyeing or unidirectional moisture wicking problems.

The invention discloses a high-shrinkage easy-to-dye mixed fiber and a preparation method thereof.The method comprises the steps that polyester melt is extruded and cooled to prepare nascent fibers, part of the nascent fibers are oiled and drafted to prepare FDY, and the other nascent fibers are oiled to prepare POY; the FDY filaments and the POY filaments are subjected to network fiber blending and winding to obtain blended filaments; the drafting is five-roller drafting, the temperature of a hot roller HR1, the temperature of a hot roller HR2 and the temperature of a hot roller HR3 are 82-87 DEG C, the temperature of a hot roller HR4 and the temperature of a hot roller HR5 are 95-105 DEG C, and the draw ratios of the hot roller HR1, the hot roller HR2, the hot roller HR3, the hot roller HR4 and the hot roller HR5 are 1.01-1.2, 1.10-1.5, 2.5-3.0 and 1 in sequence; the draw ratio of a spinning nozzle during extrusion is 165-180%; the boiling water shrinkage rate of the combined filament yarn is 60 + / -5%, and the differential shrinkage rate is 43-50%. The fabric prepared from the mixed fibers has excellent wool feeling, softness and drapability, and is outstanding in dyeing performance.

An object of the present invention is to solve a problem that when products such as films, molded products, or fibers are continuously produced from a copolymerized polyester resin copolymerized with diethylene glycol and sodium sulfoisophthalate, die contamination and adhesion of foreign matter to the products occur and a problem that during recycling of a copolymerized polyester resin copolymerized with diethylene glycol and sodium sulfoisophthalate for improving transparency and moldability, the resin is colored or the molecular weight of the resin is reduced. A copolymerized polyester resin containing terephthalic acid as a main dicarboxylic acid component and ethylene glycol as a main glycol component, wherein when a total amount of dicarboxylic acid components in all polyester resin components is taken as 100 mol%, a ratio of the terephthalic acid component to all the dicarboxylic acid components is 79.95 to 94.95 mol%, a ratio of the aliphatic acid having 6 to 40 carbon atoms to all the dicarboxylic acid components is 5 to 20 mol%, and a ratio of sodium sulfoisophthalate to all the dicarboxylic acid components is 0.05 to 10 mol%, when a total amount of glycol components is taken as 100 mol%, a ratio of diethylene glycol to all glycol components is 1 to 22 mol%, a content of a free cyclic dimer consisting of sodium sulfoisophthalate and ethylene glycol is 30 ppm or less, and a content of a free cyclic dimer consisting of terephthalic acid, sodium sulfoisophthalate, ethylene glycol and diethylene glycol is 40 ppm or less.

A thermoplastic elastomer-based multifilament yarn and a method of making a thermoplastic elastomer-based multifilament yarn are disclosed. The multifilament yarn includes a first filament at least partially adhered to a second filament. The first filament and the second filament are each formed from a thermoplastic elastomer composition comprising a thermoplastic elastomer exhibiting a flexural modulus of about 300 MPa or less as determined at a temperature of about 23 DEG C according to ISO 178: 2019. The yarn has a linear density of from about 1 to about 500 deniers per filament, and exhibits an elongation at break of about 300% or greater as determined at a temperature of about 23 DEG C according to ASTM D2653-07 (2018).

The invention relates to the technical field of copolyester staple fibers, and discloses a preparation method of biodegradable aromatic-aliphatic copolyester staple fibers, which comprises the following steps: (1) mixing terephthalic acid, glycollic acid, ethylene glycol and a catalyst, and carrying out esterification reaction to obtain an esterified substance, with the molar weight ratio of terephthalic acid to glycollic acid being (60-80%): (20-40%), the total percentage is 100%. Mixing the esterified product with an antioxidant and a stabilizer, and performing condensation polymerization to obtain copolyester; and (2) drying the copolyester, carrying out melt extrusion, cooling to obtain a protofilament, bundling, oiling, drafting and shaping to obtain the copolyester staple fiber. Glycollic acid is introduced as a third monomer, and the polyester structure is modified from the molecular level, so that the polyester has certain mechanical strength and good spinnability while having good degradation performance.

The present invention relates to a biodegradable resin composition and a biodegradable yarn comprising the same. The present invention relates to a biodegradable yarn comprising: a first biodegradable resin composition comprising a first biodegradable resin wherein the first biodegradable resin comprises a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and the first biodegradable resin composition has a melt index of from 6 g / 10 minutes to 15 g / 10 minutes at 190 DEG C, and a crystallization temperature of from 40 DEG C to 85 DEG C.

The invention discloses recycled polybutylene terephthalate and a preparation method thereof. The recycled polybutylene terephthalate is polybutylene terephthalate (PBT) obtained by directly carrying out chemical depolymerization and ester exchange on recycled polyethylene terephthalate and 1, 4-butanediol by using a titanium catalyst chelated with polybasic acid or polybasic alcohol and polymerizing, so that the manufacturing procedures are reduced, and products with good physical properties are produced.

A method of making a thermoplastic copolyester elastomer-based fiber is disclosed. The method comprises: providing a thermoplastic copolyester elastomer having a number average molecular weight of greater than 35,000 g / mol; and spinning the thermoplastic copolyester elastomer to provide a fiber comprising a spun thermoplastic copolyester elastomer, wherein the spun thermoplastic copolyester elastomer has a number average molecular weight that is 98% or less to 50% or more the number average molecular weight of the thermoplastic copolyester elastomer. A thermoplastic copolyester elastomer-based fiber made according to the aforementioned method and a fabric comprising the aforementioned thermoplastic copolyester elastomer-based fiber are also disclosed.

The object of the present invention to solve a problem that when products such as films, molded products, or fibers are continuously produced from a copolymerized polyester resin copolymerized with diethylene glycol and sodium sulfoisophthalate, die contamination and adhesion of foreign matter to the products occur and a problem that during recycling of a copolymerized polyester resin copolymerized with diethylene glycol and sodium sulfoisophthalate, the resin is colored or the molecular weight of the resin is reduced. A copolymerized polyester resin containing terephthalic acid as a main dicarboxylic acid component and ethylene glycol as a main diol component, wherein when a total amount of dicarboxylic acid components in all polyester resin components is taken as 100 mol %, a ratio of the terephthalic acid component to all the dicarboxylic acid components is 70 to 99.95 mol % and a ratio of sodium sulfoisophthalate to all the dicarboxylic acid components is 0.05 to 10 mol %, when a total amount of diol components is taken as 100 mol %, a ratio of diethylene glycol to all glycol components is 1 to 10 mol %, a content of a free cyclic monomer consisting of terephthalic acid, sodium sulfoisophthalate, ethylene glycol, and diethylene glycol is 20 ppm or less, and a content of a free cyclic trimer consisting of terephthalic acid, sodium sulfoisophthalate, and ethylene glycol is 200 ppm or less.