JP2022151499A - Polyester resin, fiber, and method for producing polyester resin - Google Patents

Abstract

To provide a polyester resin from which a fiber that is excellent in dyeability with a cation dye and is also excellent in yarn quality characteristics (strength and extensibility) can be obtained with good operability.SOLUTION: A polyester resin contains a dicarboxylic acid component and a glycol component. In the polyester resin, the dicarboxylic acid component contains a terephthalic acid as a main component and an aromatic dicarboxylic acid having a metal sulfonate group, the glycol component contains ethylene glycol as a main component and contains diethylene glycol and triethylene glycol, and a content of the triethylene glycol in the glycol component is 0.5 mol% or more and 5.5 mol% or less.SELECTED DRAWING: None

Description

The present invention relates to polyester resins, fibers, and methods of making polyester resins.

Polyester resins represented by polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc. have excellent mechanical and chemical properties and are used in a wide range of fields (for example, clothing and industrial applications). fibers for materials, films or sheets for packaging and magnetic tape, bottles that are hollow molded products, casings for electrical and electronic parts, and other engineering plastic molded products).

Conventionally, an antimony-based metal-based catalyst is known as a polycondensation catalyst used in the polycondensation of polyester resins. Antimony-based catalysts are inexpensive and have excellent catalytic activity. problems or cause surface imperfections in the workpiece.

Therefore, copolyesters suitable for polyester fibers with excellent cationic dyeability, which are produced without using antimony-based catalysts as polycondensation catalysts, have been investigated (for example, Patent Document 1).

JP 2006-63215 A

In Patent Literature 1, a metal-based catalyst such as magnesium is used, but there are still problems such as deterioration of operability due to deposition of metal during polymerization or poor color tone. Therefore, polyester resins using organic catalysts are also being investigated.
In recent years, from the viewpoint of environmental friendliness, organic catalysts have been used to produce polyester resins that are excellent in dyeability with cationic dyes and that are excellent in both strength and elongation properties. is desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester resin which uses an organic catalyst and which is excellent in dyeability with cationic dyes and which can yield polyester fibers having excellent strength and elongation properties.

As a result of intensive studies to solve the above problems, the present inventors have found that the dicarboxylic acid component contains an aromatic dicarboxylic acid having a metal sulfonate group, the glycol component contains diethylene glycol and triethylene glycol, and the glycol component contains The inventors have found that the polyester resin of the present invention having a triethylene glycol content within a specific range has excellent dyeability with cationic dyes and excellent strength and elongation properties when made into a fiber, and thus arrived at the present invention.

That is, the gist of the present invention is as follows (1) to (10).
(1) A polyester resin containing a dicarboxylic acid component and a glycol component, wherein the dicarboxylic acid component contains terephthalic acid as a main component and an aromatic dicarboxylic acid having a metal sulfonate group,
The glycol component contains ethylene glycol as a main component and also contains diethylene glycol and triethylene glycol, and the content of triethylene glycol in the glycol component is 0.5 mol % or more and 5.5 mol % or less. polyester resin.
(2) The polyester resin according to (1), wherein the content of diethylene glycol in the glycol component is 2.5 mol% or more.
(3) The polyester resin according to (1) or (2), wherein the glycol component contains tetraethylene glycol and the content of tetraethylene glycol in the glycol component is 2.0 mol % or less.
(4) The polyester resin according to (3), wherein the total content of triethylene glycol and tetraethylene glycol in the glycol component is 7.0 mol % or less.
(5) The polyester resin according to any one of (1) to (4), wherein the content of the aromatic dicarboxylic acid having a metal sulfonate group in the dicarboxylic acid component is 0.5 to 5.5 mol%.
(6) The dicarboxylic acid component according to any one of (1) to (5), wherein the dicarboxylic acid component contains an aliphatic dicarboxylic acid having 5 to 10 carbon atoms, and the content in the dicarboxylic acid component is 2 to 18 mol%. polyester resin.
(7) The polyester resin according to any one of (1) to (6), wherein the dicarboxylic acid component contains isophthalic acid and the content in the dicarboxylic acid component is 8 to 15 mol%.
(8) The polyester resin according to any one of (1) to (7), wherein the content of sulfur components other than the aromatic dicarboxylic acid having a metal sulfonate group is 5-100 ppm.
(9) A fiber made of the polyester resin according to any one of (1) to (8).
(10) A method for producing a polyester resin according to any one of (1) to (8), wherein an organic sulfonic acid compound is added to the polyester raw material, and the A method for producing a polyester resin, comprising the step of performing an etherification reaction of a glycol component by heating at a temperature of from 5 to 120 minutes.

The polyester resin of the present invention uses an organic sulfonic acid-based compound as a catalyst, and can obtain polyester fibers having excellent dyeability with cationic dyes and excellent strength and elongation with good workability.

The polyester resin of the present invention will be described in detail below.
The polyester resin of the present invention contains a dicarboxylic acid component and a glycol component. The dicarboxylic acid component contains terephthalic acid as a main component, and further contains an aromatic dicarboxylic acid having a metal sulfonate group. That is, terephthalic acid is used as the main acid component, and an aromatic dicarboxylic acid having a metal sulfonate group is used as a copolymer component. By copolymerizing an aromatic dicarboxylic acid having a metal sulfonate group, the polyester resin can be imparted with cationic dyeability.

When the total amount of all acid components constituting the polyester is 100 mol%, the content of the aromatic dicarboxylic acid having a metal sulfonate group is preferably 0.5 to 5.5 mol%, and 0.8 More preferably ~5.0 mol%.
When the content of the aromatic dicarboxylic acid having a metal sulfonate group is less than 0.5 mol%, the number of dyeing sites for the cationic dye in the entire polymer (the number of reactive groups that react with the cationic dye) is not sufficient. When the polyester resin is used to make fibers, there are cases where sufficient dyeability cannot be obtained.

On the other hand, when the content exceeds 5.5 mol %, the melt viscosity of the polyester tends to be too high in the polycondensation step, and it may be difficult to sufficiently increase the degree of polymerization. As a result, the strength of the material (for example, yarn strength when made into fibers) may decrease.
In addition, since the aromatic dicarboxylic acid having a metal sulfonate group acts as a catalyst in the etherification step described later, by setting the content within the above range, the content of ethylene glycol and triethylene glycol in the glycol component can be reduced to a specific range. can be

Aromatic dicarboxylic acids having a metal sulfonate group include, for example, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, sodium sulfonaphthalenedicarboxylic acid, sodium sulfophenyldicarboxylic acid, 5-sodium Examples include sulfoterephthalic acid and the like, but in the present invention, from the viewpoint of color development by cationic dyes, runnability during melt spinning and drawing when making fibers (hereinafter simply referred to as runnability), and cost, 5- Sodium sulfoisophthalic acid is preferably used. These acids may be used as they are, but ester-forming derivatives may also be used. Among them, esters with ethylene glycol are preferably used from the viewpoint of workability.

The proportion of terephthalic acid in the acid component is preferably 75-99.5 mol %, preferably 85-99 mol %. If the proportion of terephthalic acid is less than 75 mol %, the crystallinity of the resin composition may be lowered, the melting point may be lowered, and the workability may be lowered. On the other hand, when the proportion of terephthalic acid exceeds 99.5 mol %, the copolymerization amount of the aromatic dicarboxylic acid having a metal sulfonate group decreases, so the effect of dyeability with cationic dyes may decrease.

Furthermore, the acid component constituting the polyester preferably contains 2 to 18 mol % of an aliphatic dicarboxylic acid having 5 to 10 carbon atoms when the total amount of all acid components is 100 mol %.
By copolymerizing an appropriate amount of an aromatic dicarboxylic acid having a metal sulfonate group and an aliphatic dicarboxylic acid having 5 to 10 carbon atoms, the polyester resin can be imparted with cationic dyeability under normal pressure conditions.

When the content (copolymerization amount) of the aliphatic dicarboxylic acid having 5 to 10 carbon atoms is less than 2 mol%, the copolyester fiber has poor dyeability with cationic dyes under normal pressure conditions. be enough. On the other hand, if the content of the aliphatic dicarboxylic acid component exceeds 18 mol %, the thermal stability of the copolyester is lowered, resulting in low fiber strength.

Examples of aliphatic dicarboxylic acids having 5 to 10 carbon atoms include glutaric acid, adipic acid, pimelic acid, suberic acid, and sebacic acid. Acids are preferably used.

Further, the polyester resin of the present invention preferably contains 8 to 15 mol % of isophthalic acid in the acid component constituting the polyester, when the total amount of all acid components is 100 mol %. By containing 8 mol % or more of isophthalic acid, the fiber can have high heat shrinkability. For example, when it is used in a side-by-side type composite fiber with another polyester resin, it is possible to obtain a woven or knitted fabric having both cationic dyeability and stretchability. On the other hand, when the content of isophthalic acid exceeds 15 mol %, the strength of the yarn tends to decrease and the workability during spinning tends to deteriorate.

Acid components other than terephthalic acid, aromatic dicarboxylic acids having a metal sulfonate group, aliphatic dicarboxylic acids having 5 to 10 carbon atoms, and isophthalic acid in the polyester resin of the present invention include phthalic acid, phthalic anhydride, and naphthalenedicarboxylic acid. , 1,4-cyclohexanedicarboxylic acid, dodecanedioic acid, etc., dimer acid, trimellitic anhydride, trimellitic acid, pyromellitic acid, 1,4-cyclohexanedicarboxylic acid, dimer acid, etc., and these are 2 More than one kind may be used in combination, and ester-forming derivatives of these acids may also be used.

The polyester resin of the present invention contains diethylene glycol and triethylene glycol, and the triethylene glycol content is 0.5 mol % or more and 5.5 mol % when the total amount of all glycol components constituting the polyester is 100 mol %. mol% or less. Among them, the content of triethylene glycol is preferably 0.6 mol % or more and 5.0 mol % or less, and more preferably 0.7 mol % or more and 4.0 mol % or less. If it is less than 0.5 mol %, the workability is poor, and the effect of dyeability when made into fibers and excellent yarn properties (strength and elongation) are not sufficiently exhibited. On the other hand, when it exceeds 5.5 mol %, the melting point becomes low, and the workability and heat resistance deteriorate.

The total content of triethylene glycol and tetraethylene glycol in all glycol components is preferably 7.0 mol% or less, more preferably 0.6 mol% or more and 4.0 mol% or less, More preferably, it is 0.8 mol % or more and 3.0 mol % or less. If it exceeds 7.0 mol %, the heat resistance may be lowered, and the operability of the fiber and the thread quality of the fiber may be deteriorated. On the other hand, when the content is less than 0.6 mol %, the workability and dyeability of fibers may be poor.

The content of tetraethylene glycol is preferably 2.0 mol % or less, more preferably 1.0 mol % or less, and even more preferably 0.5 mol % or less in all glycol components. If it exceeds 2.0 mol %, heat resistance and thread quality may deteriorate.

The content of diethylene glycol is preferably 2.5 mol % or more, more preferably 3.5 mol % or more, and even more preferably 4.5 mol % or more in the total glycol components. By setting the content of diethylene glycol within this range, the dyeability of the fiber can be improved. The upper limit of the content of diethylene glycol is preferably 12 mol % from the viewpoint of workability and yarn properties.

In order to adjust the content of each of diethylene glycol, triethylene glycol, and tetraethylene glycol, for example, the content of the aromatic dicarboxylic acid having a metal sulfonate group is adjusted to a preferable range, or the polymerization in the method for producing a polyester resin described later. Using an organic sulfonic acid-based compound as a catalyst, adjusting the amount of the organic sulfonic acid-based compound to be added within a preferable range, or adjusting the molar ratio ( G/A) can be set within a preferred range, and the temperature or time in the etherification reaction can be adjusted.

The polyester resin of the present invention may contain glycol components other than those mentioned above. Specific examples include 1,2-propylene glycol, neopentyl glycol, 1,6-hexanediol, 1,4-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, dimer diol, and bisphenol. An ethylene oxide adduct of S, an ethylene oxide adduct of bisphenol A, and the like can be used.

The polyester resin of the present invention preferably has an intrinsic viscosity of 0.45 dl/g or more, more preferably 0.5 dl/g or more, still more preferably 0.6 to 0.8 dl/g. If the intrinsic viscosity is less than 0.45 dl/g, sufficient yarn quality properties may not be obtained.

In addition, the intrinsic viscosity in the present invention is a value measured at a temperature of 20° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent.

The polyester resin of the present invention can be any polymer, antistatic agent, antifoaming agent, dyeability improver, dye, pigment, matting agent, fluorescent brightening agent, stabilizer, as long as the effects of the present invention are not impaired. , antioxidants, colorants, flame retardants, and other additives may be added. Examples of antioxidants include aromatic amine-based and phenol-based antioxidants. Examples of stabilizers include phosphorus-based stabilizers such as phosphoric acid or phosphate-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers.

The polyester resin of the present invention may contain an organic, inorganic, or organometallic toner, or a fluorescent brightening agent, etc., as long as the effects of the present invention are not impaired. Thereby, coloring such as yellowing of the polyester resin can be further suppressed. Alternatively, other resins such as polyethylene or inorganic nucleating agents such as talc may be added to improve crystallinity.

A cobalt compound may be added to the polyester resin of the present invention for the purpose of improving the color tone, etc., as long as the effects of the present invention are not impaired. The cobalt compound is not particularly limited, but specific examples thereof include cobalt acetate, cobalt nitrate, cobalt chloride, cobalt acetylacetonate, cobalt naphthenate, and hydrates thereof. Among them, cobalt acetate tetrahydrate is particularly preferred. The amount of the cobalt compound added is preferably 10 ppm or less, more preferably 5 ppm or less, and still more preferably 3 ppm or less, relative to the polyester resin in terms of cobalt atoms.

The polyester resin of the present invention may be mixed with waste resin generated in the manufacturing process or recycled polyester resin collected from the market (for example, PET bottles, etc.).

(Method for producing polyester resin)
In the method for producing a polyester resin of the present invention, an organic sulfonic acid compound is added to a polyester raw material, and heated at a temperature of 240 ° C. or higher for 5 to 120 minutes at normal pressure or under pressure to etherify the glycol component. including the step of conducting the reaction.

In the present invention, the content of diethylene glycol and triethylene glycol can be set within a specific range by including a step of performing an etherification reaction under specific conditions before performing a polycondensation reaction. As a result, a polyester resin having excellent workability and dyeability can be obtained.

Raw materials for the polyester resin include, for example, a glycol component containing ethylene glycol as a main component, a dicarboxylic acid component, and an esterified product as a low-order condensate composed of a glycol component and a dicarboxylic acid component.

As a method for obtaining the esterified product, for example, when producing polyethylene terephthalate as a polyester resin, terephthalic acid, ethylene glycol, and if necessary, other copolymer components are directly reacted to distill off water to obtain an ester. to obtain an esterified product as a raw material for a polyester resin. Alternatively, dimethyl terephthalate, ethylene glycol and, if necessary, other copolymer components are reacted to distill off the methyl alcohol and transesterify to obtain an esterified product.

The method for preparing the esterified product will be described below.
A slurry containing ethylene glycol in an amount of preferably 1.02 to 2.5 mol, more preferably 1.03 to 1.8 mol per 1 mol of dicarboxylic acid or ester derivative thereof is prepared. It is continuously supplied to an esterification reactor to obtain an esterified product.

The esterification reaction is carried out under the condition that ethylene glycol is refluxed while removing water or alcohol produced by the reaction out of the system in a rectifying column. The esterification reaction can be carried out using a multi-stage apparatus in which multiple esterification reactors are connected in series.

When the esterification reaction is carried out in multiple stages, the temperature of the esterification reaction in the first stage is preferably 240 to 270°C, more preferably 245 to 265°C. The pressure is preferably 0.2-3 kg/cm ² G, more preferably 0.5-2 kg/cm ² G.

The temperature of the esterification reaction in the final stage is preferably 250 to 290°C, more preferably 255 to 275°C. The pressure is preferably 0-1.5 kg/cm ² G, more preferably 0-1.3 kg/cm ² G.

When the reaction is carried out in three or more stages, the reaction conditions for the esterification reaction in the intermediate stage are preferably between the reaction conditions in the first stage and the reaction conditions in the final stage.
It is preferable that the reaction rate of the multistage esterification reaction be smoothly increased in each stage. The final esterification reaction rate preferably reaches 90% or more, more preferably 93% or more. Esterified products can be obtained by these esterification reactions, and the preferred molecular weight thereof is about 500 to 5,000.

When terephthalic acid is used in the esterification reaction, the reaction proceeds due to the catalytic action of terephthalic acid as an acid.

An aromatic dicarboxylic acid having a metal sulfonate group and an alkali metal compound are added to the esterified product obtained as described above, depolymerization reaction is performed if necessary, and then the organic sulfonic acid compound is added. to carry out the etherification reaction. Thereafter, the polycondensation reaction is allowed to proceed to obtain the polyester resin of the present invention.

The amount of the aromatic dicarboxylic acid having a metal sulfonate group added to the esterified product is, for example, (esterified product)/(aromatic dicarboxylic acid having a metal sulfonate group)=4.0 to 30.0 in mass ratio. This makes it easier to set the content of the aromatic dicarboxylic acid having a metal sulfonate group within the range of the present invention and set the content of diethylene glycol and triethylene glycol within the specific ranges.

In the present invention, by using an organic sulfonic acid-based compound as a polymerization catalyst, the contents of diethylene glycol and triethylene glycol in the resulting polyester resin can be set within specific ranges. Examples of organic sulfonic acid compounds include benzenesulfonic acid, m- or p-benzenedisulfonic acid, 1,3,5-benzenetrisulfonic acid, o-, m- or p-sulfobenzoic acid, benzaldehyde-o- sulfonic acid, acetophenone-p-sulfonic acid, acetophenone-3,5-disulfonic acid, o-, m- or p-aminobenzenesulfonic acid, sulfanilic acid, 2-aminotoluene-3-sulfonic acid, phenylhydroxylamine-3 -sulfonic acid, phenylhydrazine-3-sulfonic acid, 1-nitronaphthalene-3-sulfonic acid, thiophenol-4-sulfonic acid, anisole-o-sulfonic acid, 1,5-naphthalenedisulfonic acid, o-, m- or p-chlorobenzenesulfonic acid, o-, m- or p-bromobenzenesulfonic acid, o-, m- or p-nitrobenzenesulfonic acid, nitrobenzene-2,4-disulfonic acid, nitrobenzene-3,5-disulfonic acid , nitrobenzene-2,5-disulfonic acid, 2-nitrotoluene-5-sulfonic acid, 2-nitrotoluene-4-sulfonic acid, 2-nitrotoluene-6-sulfonic acid, 3-nitrotoluene-5-sulfonic acid, 4-nitrotoluene- 2-sulfonic acid, 3-nitro-o-xylene-4-sulfonic acid, 5-nitro-o-xylene-4-sulfonic acid, 2-nitro-m-xylene-4-sulfonic acid, 5-nitro-m- xylene-4-sulfonic acid, 3-nitro-p-xylene-2-sulfonic acid, 5-nitro-p-xylene-2-sulfonic acid, 6-nitro-p-xylene-2-sulfonic acid, 2,4- Dinitrobenzenesulfonic acid, 3,5-dinitrobenzenesulfonic acid, o-, m- or p-fluorobenzenesulfonic acid, 4-chloro-3-methylbenzenesulfonic acid, 2-chloro-4-sulfobenzoic acid, 5- Sulfosalicylic acid, 4-sulfophthalic acid, 2-sulfobenzoic anhydride, 3,4-dimethyl-2-sulfobenzoic anhydride, 4-methyl-2-sulfobenzoic anhydride, 5-methoxy-2-sulfobenzoic anhydride Acid anhydride, 1-sulfonaphthoic anhydride, 8-sulfonaphthoic anhydride, 3,6-disulfophthalic anhydride, 4,6-disulfoisophthalic anhydride, 2,5-disulfoterephthalic anhydride, methane sulfonic acid, ethanesulfonic acid, methionic acid, cyclopentanesulfonic acid, 1,1-ethanedisulfonic acid, 1,2-ethanedisulfonic acid, 1,2-ethanedisulfuric acid phonic anhydride, 3-propanedisulfonic acid, β-sulfopropionic acid, isethionic acid, dithionic acid, dithionic anhydride, 3-oxy-1-propanesulfonic acid, 2-chloroethanesulfonic acid, phenylmethanesulfonic acid, β-phenylethanesulfonic acid, α-phenylethanesulfonic acid, ammonium chlorosulfonate, methyl benzenesulfonate, ethyl p-toluenesulfonate, ethyl methanesulfonate, dimethyl 5-sulfosalicylate, trimethyl 4-sulfophthalate, and the like, and These salts are mentioned. Among them, from the viewpoint of versatility, 2-sulfobenzoic anhydride, o-sulfobenzoic acid, m-sulfobenzoic acid, p-sulfobenzoic acid, 5-sulfosalicylic acid, benzenesulfonic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, p-toluenesulfonic acid, methyl p-toluenesulfonate, 5-sulfoisophthalic acid, and salts thereof.

When a metal-based catalyst is not used as the polymerization catalyst, the content of metal components derived from the metal-based catalyst in the resulting polyester resin of the present invention can be reduced. If the content of the metal component is large, foreign matter may be generated during melt spinning. The content of the metal component is preferably 1 ppm or less, more preferably 0.5 ppm or less, and even more preferably 0 ppm. Examples of metal-based catalysts include compounds such as antimony, germanium, tin, titanium, zinc, aluminum, iron, magnesium, potassium, calcium, sodium, manganese, nickel, and cobalt.

The organic sulfonic acid compound can be added, for example, in the form of a solid, a slurry, or a solution dissolved in water, glycol, or the like.

Although the amount of the organic sulfonic acid compound to be added depends on the type, it is preferably 0.5×10 ⁻⁴ to 40×10 ⁻⁴ mol per 1 mol of the acid component constituting the polyester resin. .0 to 20.0×10 ⁻⁴ mol is more preferable. If the added amount exceeds the above range and is too small, it may not be possible to obtain a polyester resin with a high degree of polymerization, and fibers having excellent strength and dyeability may not be obtained. Alternatively, the content of diethylene glycol and triethylene glycol may not fall within a specific range. On the other hand, if the content exceeds the above range and is excessive, the content of triethylene glycol may become too large, or it may cause coloring of the polyester resin.

By setting the amount of the organic sulfonic acid-based compound to be added within the above range, the content of the sulfur component other than the aromatic dicarboxylic acid having a metal sulfonate group (that is, the sulfur component derived from the catalyst) in the obtained polyester resin can be reduced to , preferably 5 to 100 ppm, more preferably 6 to 60 ppm. If the content of the sulfur component is less than 5 ppm, the fibrous properties may be poor. On the other hand, if it exceeds 100 ppm, it may cause coloring of the polyester.

The etherification reaction temperature is preferably 240°C or higher, more preferably 240°C to 300°C, even more preferably 250°C to 280°C. If the temperature is lower than 240°C, the reaction may not proceed sufficiently, and the content of diethylene glycol and triethylene glycol may not be within the specific range. If the temperature exceeds 300° C., the decomposition of the esterified product proceeds during the reaction, and the workability of the fiber and the yarn properties of the fiber may deteriorate.

The etherification reaction time is preferably 5 to 120 minutes, more preferably 10 to 60 minutes. If it is less than 5 minutes, the reaction may not proceed sufficiently, and the content of diethylene glycol and triethylene glycol may not be within the specific range. If it exceeds 120 minutes, the etherification reaction proceeds too much, and the content of diethylene glycol and triethylene glycol may not fall within the specified range, or the decomposition of the esterified product may proceed during the reaction. The operability at the time of processing and the yarn quality characteristics as a fiber may deteriorate.

The etherification reaction is preferably allowed to proceed under normal pressure or increased pressure, and the pressure is preferably from 0 to 3.0 kg/cm ² G.

By adjusting the ratio (G/A) of the glycol component and the acid component in the raw material subjected to the etherification reaction, the content of diethylene glycol and triethylene glycol can be set within a specific range. G/A is preferably 1.05 to 3.00, more preferably 1.10 to 2.00. In order to adjust the G/A, if necessary, a glycol component such as ethylene glycol may be additionally added to the polyester raw material.
When it is less than 1.05, the amount of triethylene glycol produced tends to decrease, while when it exceeds 3.00, the amount of triethylene glycol produced tends to increase.

After the etherification reaction, a polycondensation reaction can be performed to obtain the polyester resin of the present invention. Examples of polycondensation reactions include melt polycondensation reactions. The polycondensation reaction may be carried out in one step, or may be carried out in multiple steps.

The polycondensation reaction conditions are not particularly limited, but the temperature of the first-stage polycondensation reaction is preferably 250 to 290°C, more preferably 260 to 280°C. The pressure is preferably 500-20 hPa, more preferably 200-30 hPa.

In the case of multiple stages, the temperature of the polycondensation reaction in the final stage is preferably 265 to 300°C, preferably 275 to 295°C. The pressure is preferably 10 to 0.1 hPa, more preferably 5 to 0.5 hPa. When the reaction is carried out in three or more stages, the reaction conditions in the intermediate stages are preferably the reaction conditions between the first stage and the final stage. It is preferable to smoothly increase the degree of polymerization in each of these stages.

Furthermore, at the time of the polycondensation reaction, a hindered phenol-based antioxidant, a phosphorus compound capable of suppressing thermal decomposition of the resin, and titanium oxide for improving whiteness are optionally added together with the above polymerization catalyst. can also be added.

Examples of hindered phenol antioxidants include 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl ) propionate, tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 4 , 4′-butylidenebis-(3-methyl-6-t-butylphenol), triethylene glycol-bis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], 3,9-bis {2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1′-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5 ] undecane and the like are used, but tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane is preferred from the viewpoint of effect and cost. These can be used alone or in combination of two or more.

Phosphorus compounds such as phosphorous acid, phosphoric acid, trimethyl phosphite, triphenyl phosphite, tridecyl phosphite, trimethyl phosphate, triethyl phosphate, tridecyl phosphate, and triphenyl phosphate are used as the phosphorus compound. be able to. These can be used alone or in combination of two or more.

Titanium oxide is generally used as a delustering agent or white pigment for polyesters, but by adding an appropriate amount of titanium oxide to the polyester resin of the present invention, the whiteness of the fiber is improved. is preferable in that a woven or knitted fabric with a good color tone can be obtained. The amount of titanium oxide to be added is preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the polyester resin.

(Use of polyester resin)
The polyester resin of the present invention can be applied to various uses. Among them, it is suitable for fiber applications, but it can also be used for molding applications such as sheets, films and injection molded articles.

The fiber of the present invention is made of the polyester resin of the present invention.
The fiber of the present invention can be obtained, for example, by spinning using the polyester resin of the present invention. The spinning method and the like can be carried out according to known conditions. The fibers of the present invention may be, for example, ultrafine fibers having a single filament fineness of 0.8 decitex or less (preferably 0.6 to 0.3 decitex).

The fibers of the present invention may be, for example, monofilaments, multifilaments, or the like, and may be long fibers, short fibers, or the like.
The shape of the single fiber constituting the fiber of the present invention is not particularly limited, and may be not only a circular cross section but also a polygonal cross section.

The fibers of the present invention include not only fibers in which all of the single fibers are formed of the polyester resin of the present invention, but also polyester resins of the present invention and other polyester resins (virgin polyester resins and other copolymer components). It may be a conjugate fiber that is conjugated with a polyester resin, etc.). Examples of the form of the composite fiber include core-sheath type, side-by-side type, and sea-island type.

The proportion of the polyester resin of the present invention contained in the fiber of the present invention is preferably 30% by mass or more, more preferably 50% by mass or more, and further preferably 70% by mass in the fiber of the present invention. It is preferable that it is above. When the fibers of the present invention are not conjugate fibers, the content is preferably 80% by mass or more, more preferably 90% by mass or more, and more preferably 100% by mass.

When the fiber of the present invention is a multifilament, its characteristic values include, for example, a single filament fineness of 0.3 to 30 decitex, a single filament count of 2 to 300, a total fineness of 5 to 350, a strength of 1 to 5 cN/dtex, Examples include those having an elongation in the range of 10 to 400%.

The fiber of the present invention can be dyed with a cationic dye, and when dyed, does not cause mottling or color difference, and has excellent dyeability. Furthermore, it is also excellent in filament properties such as strength.

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to these. Measurement and evaluation were performed by the following methods.

(1) Intrinsic viscosity [η]
Measurement was performed at a temperature of 20° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent.

(2) Composition of polyester resin Dissolve 10 mg of sample in 1 mL of a mixed solvent of deuterated chloroform / deuterated trifluoroacetic acid = 9/1 (mass ratio), and ¹ by LA-400 type NMR manufactured by JEOL Ltd. H-NMR was measured, and the total amount of the dicarboxylic acid component, the triethylene glycol component and the tetraethylene glycol component, and the moles of each other glycol component from the peak integrated intensity of the protons of each component in the obtained chart. A ratio was calculated.
Then, triethylene glycol and tetraethylene glycol were quantified as follows.
A polyester resin was hydrolyzed in a potassium hydroxide/methanol solution having a concentration of 0.75 N, and then neutralized by adding terephthalic acid. Next, the filtrate obtained by filtration is measured by gas chromatography, and the molar ratio between triethylene glycol and tetraethylene glycol is calculated using a calibration curve prepared in advance. From the above-mentioned ¹ H-NMR measurement results (molar ratio of the total amount of triethylene glycol and tetraethylene glycol and each other glycol component), triethylene glycol and tetraethylene glycol in all glycol components The content was calculated.

(3) melting point (Tm), glass transition temperature (Tg)
Using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, measurement was performed in a nitrogen stream at a temperature range of 25 to 280°C and a heating rate of 20°C/min.

(4) Content of sulfur component derived from catalyst A polyester resin is melt-molded at 300 ° C. to form a disc-shaped molded plate with a diameter of 3 cm × thickness of 1 cm, and a calibration curve is obtained using a fluorescent X-ray analyzer ZSX Primus manufactured by Rigaku. Quantitative analysis of sulfur content was carried out by the method.
Next, 10 mg of the sample was dissolved in 1 mL of a mixed solvent of deuterated chloroform/deuterated trifluoroacetic acid = 9/1 (mass ratio), and ¹ H-NMR was analyzed with a JEOL LA-400 NMR. The molar ratio of 5-Na sulfoisophthalic acid diglycol ester (SIPG) was calculated from the proton peak integrated intensity of each component in the measured and obtained chart, and the sulfur content derived from SIPG was calculated therefrom.
The catalyst-derived sulfur content was calculated by subtracting the SIPG-derived sulfur content calculated by NMR from the sulfur content quantitatively analyzed by the fluorescent X-ray spectrometer.

The evaluation method of fibers (operability/dyeability/strength, elongation/stretchability) is as follows.
(5) Workability of fibers (thread cut during spinning)
The case where the number of yarn cuts during continuous melt spinning for 24 hours was 3 times/(day/weight) or less was rated as "good", and the other cases were rated as "poor".
(6) Workability of fibers (cutting during drawing)
The number of yarn cuts that occurred when the drawing was continued for 12 hours was counted, and the yarn cut generation rate (%) was calculated and evaluated by the following formula.
Yarn occurrence rate (%) = {(total number of spindles for drawing) - (number of spindles that could be drawn without cutting for 12 hours)} / (total number of spindles for drawing) x 100
○: Cut yarn generation rate during stretching ≤ 5%
×: Cut yarn generation rate during stretching > 5%

(7) Thread Quality According to JIS L-1013, using Autograph DSS-500 manufactured by Shimadzu Corporation, strength and elongation were measured at a grip interval of 50 cm and a pulling speed of 50 cm/min.
In the present invention, the strength is preferably 2.0 cN/dtex or more, more preferably 3.0 cN/dtex or more. Also, the elongation is preferably 28% or more, more preferably 30% or more. Satisfying the above range for both strength and elongation is an index of excellent balance of yarn properties.

(8) Dyeability The obtained multifilament was made into a tubular knitted fabric using a knitting machine (manufactured by Koike Kikai Seisakusho, number of needles: 300, hook diameter: 3.5 inches). The produced tubular knitted fabric was dyed with Astorazon Blue FRR and dyed with acetic acid, sodium acetate and Ionet as auxiliaries. w. f. Dyeing was performed at 130° C. for 30 minutes under the following conditions. The 30 dyed tubular knitted fabrics were visually observed to evaluate the presence or absence of staining streaks and staining spots.
○: Number of good products is 27 or more ×: Number of good products is 26 or less

(9) Normal pressure dyeability (L value after dyeing)
A tubular knitted fabric was produced from the obtained multifilament yarn using a knitting machine (manufactured by Koike Kikai Seisakusho, number of needles: 300, hook diameter: 3.5 inches).
The produced tubular knitted fabric was scouring at 60° C. for 20 minutes, then under normal pressure dyeing at 100° C. for 60 minutes under the following dyeing conditions, and air-dried. Next, after performing heat setting at 150° C. for 1 minute using a small pin tenter, a four-ply sample piece was prepared. The L value of this sample piece was measured with a color difference meter to evaluate dyeability. The lower the L value, the darker the color of the fiber, and it was judged that the dyeability was good, and the L value of 35 or less was accepted.
In addition, 30 dyed tubular knitted fabrics were visually evaluated for the presence or absence of staining streaks and staining spots, and the number of non-defective products having neither staining streaks nor staining spots was counted and evaluated as follows.
○: The number of good products is 27 or more ×: The number of good products is 26 or less (dyeing conditions)
Dye: Astrazon Blue 0.5% o. m. f.
Leveling agent: Acetic acid 0.2mL/L
Sodium acetate 0.2g/L
Bath ratio: 1:50
(10) Stretchability Sensory evaluation was performed by 10 panelists on the sample (tubular knitted fabric) used for dyeability evaluation. It was evaluated on a 10-point scale from 1 to 10, and the highest stretchability was given a perfect score of 10, and the average value of 10 people was shown. A score of 7 or more was evaluated as ◯, and a score of less than 7 was evaluated as x.

[Preparation of esterified product]
A slurry of terephthalic acid and ethylene glycol (molar ratio: 1/1.6) was continuously supplied to an esterification reactor, and reacted at a temperature of 250°C and a pressure of 0.2 MPa, with a residence time of 8 hours. An esterified product (terephthalic acid: ethylene glycol = 100:111 (molar ratio)) was obtained.

Example 1
[Polyester resin]
The heat-melted esterified product and 5-Na sulfoisophthalic acid diglycol ester (SIPG) as a polymerization catalyst were put into a polycondensation reaction vessel heated to 280° C., and 5-sulfosalicylic acid dihydrate (SS) was added to 2. 0×10 ⁻⁴ mol/mol of acid component was added and an etherification reaction was carried out at 260° C. for 10 minutes under normal pressure. Next, while maintaining the temperature of the reactor at 280° C., the system pressure was gradually reduced to 0.5 hPa or less after 60 minutes. A polycondensation reaction was carried out for 3 hours while stirring under these conditions to obtain a polyester resin. The polyester resin contained 25 ppm of catalyst-derived sulfur components and had a triethylene glycol content of 1.1 mol %.

[Manufacturing of long fibers]
After drying the obtained polyester resin, it is spun at a spinning temperature of 303° C. using a spinneret having 84 discharge holes, and is wound at a speed of 2900 m/min while cooling and applying an oil solution to obtain a partially oriented yarn. got This was drawn under conditions of a roll heater temperature of 90° C., a plate heater of 150° C. and a drawing speed of 600 m/min, and then wound to obtain a multifilament yarn (drawn yarn) of 45 decitex/84 filaments.

Examples 2-6, Comparative Examples 1-7
[Polyester resin]
As shown in Table 1, except that the amount of 5-Na sulfoisophthalic acid diglycol ester (SIPG) added, the amount of 5-sulfosalicylic acid dihydrate (SS) added, and the etherification conditions were changed, A polyester resin was obtained by performing the same operation as in 1.
Then, in the same manner as in Example 1, a multifilament yarn was obtained.

Comparative example 8
A polyester resin was obtained in the same manner as in Example 1 except that antimony trioxide (Sb) was used instead of 5-sulfosalicylic acid dihydrate (SS). Then, in the same manner as in Example 1, a multifilament yarn was obtained.

Example 7
A polyester resin was obtained in the same manner as in Example 1, except that 2.1 parts by mass of isophthalic acid (IPA) was added to the polycondensation reactor. The obtained polyester resin and the polyester resin obtained in Example 3 are used as the other polyester resin, and these resins are dried and then supplied to a composite spinning melt extruder in equal mass, spinning at a spinning temperature of 290. °C, the two components were combined upstream of a spinneret having 12 discharge holes, joined side-by-side and spun. After the spun yarn was cooled and solidified, it was wound up at a speed of 3000 m/min while applying oil to obtain an undrawn yarn. Next, after heat treatment with a roller at a temperature of 85° C., it was simultaneously drawn at a draw ratio of 1.7 and heat treated at 185° C. (heat plate temperature) to obtain a multifilament yarn of 56 decitex/12 filament composite fiber. .

Examples 8 and 9
A polyester resin was obtained in the same manner as in Example 7, except that the amount of isophthalic acid (IPA) added was changed. Then, in the same manner as in Example 7, a multifilament yarn was obtained.

Example 10
A polyester resin was obtained in the same manner as in Example 1, except that 1.8 parts by mass of adipic acid (AD) was added to the polycondensation reactor. Then, in the same manner as in Example 1, a multifilament yarn was obtained.

Examples 11 and 12
A polyester resin was obtained in the same manner as in Example 10, except that the amount of adipic acid (AD) added was changed. Then, in the same manner as in Example 1, a multifilament yarn was obtained.

Table 1 shows the raw material composition, production conditions, and obtained polyester resin composition of the polyester resin in Examples and Comparative Examples.

Table 2 shows the characteristic values of the polyester resins and fibers obtained in Examples and Comparative Examples.

As shown in Table 2, the polyester resins obtained in Examples 1 to 12 had diethylene glycol and triethylene glycol contents within the range specified in the present invention, so that they had excellent dyeability with cationic dyes, and yarn It was possible to obtain fibers excellent in quality characteristics (strength and elongation) with good workability.
Among them, the composite fibers using the polyester resin obtained in Examples 7 to 9 were also excellent in stretchability. The polyester resin fibers obtained in Examples 10 to 12 were also excellent in normal pressure dyeability.

On the other hand, in Comparative Example 1, since the content of the aromatic dicarboxylic acid having a metal sulfonate group was high, the content of triethylene glycol in the polyester resin was increased. As a result, the resulting resin was amorphous and had poor heat resistance, resulting in poor spinning operability and poor dyeing quality.

In Comparative Example 2, since the content of the aromatic dicarboxylic acid having a metal sulfonate group was low, the triethylene glycol content in the polyester resin was low. As a result, the resin had a high melting point and poor workability in stretching.

In Comparative Example 3, since no etherification reaction was performed, the content of triethylene glycol in the polyester resin was low, resulting in poor workability in stretching.

In Comparative Example 4, since the amount of 5-sulfosalicylic acid dihydrate added as a polymerization catalyst was large, the content of triethylene glycol in the polyester resin increased, and as a result, the polyester resin was amorphous and had low heat resistance. turned into resin. The spinnability was poor, and the dyeing quality was also poor.

In Comparative Example 5, since the amount of 5-sulfosalicylic acid dihydrate added as a polymerization catalyst was small, the triethylene glycol content was small. As a result, the operability in stretching was poor.

In Comparative Example 6, since the etherification reaction temperature was lowered, the triethylene glycol content in the polyester resin was reduced. As a result, the operability in stretching was poor.

In Comparative Example 7, the content of triethylene glycol in the polyester resin was increased by lengthening the etherification reaction time. As a result, an amorphous resin with low heat resistance was obtained. The spinnability was poor, and the dyeing quality was also poor.

In Comparative Example 8, antimony trioxide was added instead of 5-sulfosalicylic acid dihydrate (SS) as the polymerization catalyst, so the triethylene glycol content in the polyester resin was reduced. As a result, the operability in stretching was poor.

Claims (10)

A polyester resin containing a dicarboxylic acid component and a glycol component, wherein the dicarboxylic acid component contains terephthalic acid as a main component and an aromatic dicarboxylic acid having a metal sulfonate group,
The glycol component contains ethylene glycol as a main component and also contains diethylene glycol and triethylene glycol, and the content of triethylene glycol in the glycol component is 0.5 mol % or more and 5.5 mol % or less. polyester resin. The polyester resin according to claim 1, wherein the content of diethylene glycol in the glycol component is 2.5 mol% or more. 3. The polyester resin according to claim 1, wherein the glycol component contains tetraethylene glycol, and the content of tetraethylene glycol in the glycol component is 2.0 mol % or less. 4. The polyester resin according to claim 3, wherein the total content of triethylene glycol and tetraethylene glycol in the glycol component is 7.0 mol % or less. The polyester resin according to any one of claims 1 to 4, wherein the content of the aromatic dicarboxylic acid having a metal sulfonate group in the dicarboxylic acid component is 0.5 to 5.5 mol%. The polyester resin according to any one of claims 1 to 5, wherein the dicarboxylic acid component contains an aliphatic dicarboxylic acid having 5 to 10 carbon atoms, and the content in the dicarboxylic acid component is 2 to 18 mol%. The polyester resin according to any one of claims 1 to 6, wherein the dicarboxylic acid component contains isophthalic acid and the content in the dicarboxylic acid component is 8 to 15 mol%. The polyester resin according to any one of claims 1 to 7, wherein the content of sulfur components other than the aromatic dicarboxylic acid having a metal sulfonate group is 5 to 100 ppm. A fiber made of the polyester resin according to any one of claims 1 to 8. A method for producing a polyester resin according to any one of claims 1 to 8, wherein an organic sulfonic acid compound is added to the polyester raw material, and the temperature is 240 ° C. or higher under normal pressure or pressure. A method for producing a polyester resin, comprising the step of heating for 5 to 120 minutes to etherify a glycol component.