JP2023034955A - polyester resin - Google Patents

Abstract

To provide a polyester resin which suppresses hydrolysis under high temperature and high humidity, and is excellent in moist heat resistance.SOLUTION: A polyester resin contains 1-500 ppm of a sulfur component, and one or more compounds of an alkali metal compound, an alkali earth metal compound and an organic base-containing compound. The polyester resin has a ratio (A/B) of an intrinsic viscosity retention rate (A) when subjected to moist heat treatment under conditions of a temperature of 40°C, relative humidity of 100% and 240 hours to an intrinsic viscosity retention rate (B) when subjected to moist heat treatment under conditions of a temperature of 130°C, relative humidity of 100% and 48 hours of 1.1 to 4.0.SELECTED DRAWING: None

Description

The present invention relates to 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 such as clothing and industrial applications. It is used in fibers for materials, films or sheets for packaging and magnetic tape, bottles as hollow molded products, casings for electrical and electronic parts, and other engineering plastic molded products.

In recent years, from the viewpoint of reducing the burden on the environment, the use of organic catalysts in place of metal catalysts in the polymerization of polyester resins has also been investigated. For example, organic sulfonic acid compounds such as p-toluenesulfonic acid have been proposed (eg, Patent Document 1). Organic sulfonic acid-based compounds have excellent polymerization activity, and the polyesters produced using them have good color tone.

Japanese Patent Publication No. 63-033489

Polyester resins produced using organic sulfonic acid compounds are particularly susceptible to hydrolysis in high-temperature and high-humidity environments, and in recent years, there has been a demand for further improvement in resistance to moist heat.

As a result of intensive studies by the present inventors to solve the above problems, the polyester resin containing one or more compounds selected from alkali metal compounds, alkaline earth metal compounds, and organic base-containing compounds is an organic sulfone. The inventors have found that even those produced using an acid-based compound are inhibited from progressing hydrolysis under high temperature and high humidity conditions, and have excellent resistance to moist heat, and have arrived at the present invention.

Polyester resins containing a dicarboxylic acid component and a glycol component of the present invention are as follows (1) to (5).
(1) Containing 1 to 500 ppm sulfur component, containing one or more compounds selected from alkali metal compounds, alkaline earth metal compounds, and organic base-containing compounds, temperature 40 ° C., relative humidity 100%, 240 Ratio (A/ A polyester resin characterized in that B) is from 1.1 to 4.0.
(2) A fiber made of the polyester resin composition of (1).
(3) A film made of the polyester resin composition of (1).
(4) A molded article made of the polyester resin composition of (1).
(5) An adhesive comprising the polyester resin composition of (1).

The polyester resin of the present invention is inhibited from being hydrolyzed under high temperature and high humidity conditions, and even when the temperature of the usage environment changes from low to high, the progress of hydrolysis is inhibited. be.

The polyester resin of the present invention will be described in detail below.
The polyester resin of the present invention contains 1 to 500 ppm of a sulfur component and at least one compound selected from an alkali metal compound, an alkaline earth metal compound and an organic base-containing compound.

Examples of the dicarboxylic acid component constituting the polyester include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, (anhydrous) phthalic acid, 2,6-naphthalenedicarboxylic acid, and 5-sodiumsulfoisophthalic acid, oxalic acid, (anhydrous) ) succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, dimer acid having 20 to 60 carbon atoms, (anhydrous) maleic acid, fumaric acid, (anhydrous) itaconic acid, (anhydrous) citraconic acid, mesaconic acid, etc. ( Polyfunctional carboxylic acids such as (anhydrous) trimellitic acid, trimesic acid, (anhydrous) pyromellitic acid, and ester-forming derivatives thereof can be mentioned. In the present invention, it is preferable to use terephthalic acid as a main component.

Examples of glycol components constituting polyester include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentyl glycol; Examples include alicyclic diols such as 1,4-cyclohexanedimethanol and 1,4-cyclohexanediethanol, and aromatic diols such as ethylene oxide of bisphenol A and bisphenol S, and propylene oxide adducts. Furthermore, trimethylolpropane, glycerin, polyfunctional alcohols such as pentaerythritol, and the like are included. In the present invention, it is preferable to use ethylene glycol as a main component.

The polyester resin of the present invention has a sulfur content of 1 to 500 ppm, preferably 5 to 300 ppm, even more preferably 10 to 200 ppm, and particularly preferably 15 to 150 ppm. The sulfur component is preferably contained derived from an organic sulfonic acid compound used as a polymerization catalyst in the production method described below.
If the content exceeds 500 ppm, the resin will have a low degree of polymerization, and the molecular weight will not increase sufficiently, resulting in inferior moldability and strength. In addition, excessive hydrolysis may cause a decrease in strength when formed into a molded article or fiber, which may not be practical.

The polyester resin of the present invention contains one or more compounds selected from alkali metal compounds, alkaline earth metal compounds and organic base-containing compounds.
In the production method described below, the organic sulfonic acid compound used as a polymerization catalyst tends to accelerate the hydrolysis of the polyester. In the present invention, hydrolysis is suppressed by containing one or more compounds selected from alkali metal compounds, alkaline earth metal compounds, and organic base-containing compounds as neutralization or reaction components for organic sulfonic acid compounds. can do. In particular, hydrolysis can be suppressed when the temperature of the usage environment changes from low to high.

The total content of the alkali metal compound, alkaline earth metal compound and organic base-containing compound is preferably 1 to 1000 ppm, more preferably 1 to 700 ppm. If it is less than 1 ppm, hydrolysis may tend to proceed. If it exceeds 1000 ppm, the polymerizability may deteriorate.

Examples of alkali metal compounds include lithium acetate, sodium acetate, potassium acetate, sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium hydrogen carbonate, lithium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, lithium carbonate, potassium carbonate, sodium borohydride, lithium borohydride, potassium borohydride, sodium stearate, lithium stearate, potassium stearate, sodium benzoate, lithium benzoate, potassium benzoate and the like.

Examples of alkaline earth metal compounds include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, and magnesium carbonate. , strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, magnesium stearate, strontium stearate and the like.
Among the alkali metal compounds and alkaline earth metal compounds, acetates and hydroxides are preferred because they are highly soluble in ethylene glycol and further improve the suppression of hydrolysis when considering the addition to the reaction system. preferable.

Examples of organic base-containing compounds include 1-methylimidazole, diethylamine, triethylamine, dipropylamine, isopropylamine, isobutylamine, monoethanolamine, diethanolamine, triethanolamine, ammonia, N,N-dimethylethanolamine, aminoethanol. , dimethylaminoethanol, diethylaminoethanol, ethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, n-butylamine, 2-methoxyethylamine, 3-methoxypropylamine, 2,2-dimethoxyethylamine , morpholine, N-methylmorpholine, N-ethylmorpholine, pyrrole, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, diethanolamine, N,N-dimethyl-ethanolamine, N,N-diethyl -ethanolamine, 2-dimethylamino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol, N-methyldiethanolamine, N-ethyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine is mentioned.
Among them, 1-methylimidazole, diethylamine, triethylamine, dipropylamine, isopropylamine, isobutylamine, monoethanolamine, diethanolamine, and triethanolamine are preferable from the viewpoint of cost and hydrolysis resistance.

The polyester resin of the present invention may contain an antioxidant.
Antioxidants include, for example, hindered phenol-based antioxidants. 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] and undecane.

The polyester resin of the present invention may contain an anti-coloring agent.
Examples of coloring inhibitors include phosphorous acid, phosphoric acid, polyphosphoric acid, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, tridecyl phosphite, trimethyl phosphate, tridecyl phosphate, triphenyl phosphate, and the like. of phosphorus compounds.

The polyester resin of the present invention may contain a crystal nucleating agent.
Crystal nucleating agents include carbon black, calcium carbonate, synthetic silicic acid and silicates, zinc oxide, high-site clay, kaolin, basic magnesium carbonate, mica, talc, quartz powder, diatomaceous earth, dolomite powder, and titanium oxide. , zinc oxide, barium sulfate, calcium sulfate, alumina, calcium silicate, boron nitride, etc., low-molecular-weight organic compounds having a metal salt of a carboxyl group, such as octylic acid, toluic acid, heptanoic acid, pelargonic acid, lauric acid, myristic Metal salts such as acid, palmitic acid, stearic acid, behenic acid, cerotic acid, montanic acid, melissic acid, benzoic acid, p-tert-butylbenzoic acid, terephthalic acid, terephthalic acid monomethyl ester, isophthalic acid, isophthalic acid monomethyl ester etc.

The polyester resin of the present invention preferably has an intrinsic viscosity retention rate (A) of 70% or more when subjected to wet heat treatment under conditions of a temperature of 40° C. and a relative humidity of 100% for 240 hours. When the intrinsic viscosity retention rate (A) is in the above range, for example, when exposed to high temperature and high humidity such as outdoors, when pre-cooked food is enclosed when used as a retort packaging material, hot PET bottles Even when it is used, it serves as an index for suppressing the progress of hydrolysis.

The polyester resin of the present invention is excellent in hydrolysis resistance at higher temperatures, and the intrinsic viscosity retention rate (B) when wet heat treated under the conditions of 130 ° C., 100% relative humidity, and 48 hours is 25%. It is preferable that it is above. When the intrinsic viscosity retention rate (B) is in the above range, for example, the scouring process and dyeing process when used as a fiber, the processing process when used as a molded product, film, or adhesive, and when used as a retort packaging material. It serves as an index for suppressing the progress of hydrolysis even in a high-temperature and high-humidity environment such as during retort processing.

ADVANTAGE OF THE INVENTION The polyester resin of this invention does not change heat-and-moisture resistance largely even when the temperature in a usage environment fluctuates, and progress of hydrolysis is suppressed.
As an indicator, the intrinsic viscosity retention rate (A) when wet heat treated under conditions of temperature 40 ° C., relative humidity 100%, 240 hours, and temperature 130 ° C., relative humidity 100%, when wet heat treated under conditions of 48 hours The ratio (A/B) to the intrinsic viscosity retention rate (B) is 1.1 to 4.0, preferably 1.1 to 3.5, and 1.1 to 2.5 is more preferred.
When the ratio of the intrinsic viscosity retention rates (A) and (B) is within the above range, it is possible to suppress the progress of hydrolysis even in a use environment with temperature fluctuations.
Such usage environments include, for example, when the polyester resin of the present invention is used as a fiber, when it is subjected to a scouring process or a dyeing process after washing with hot water, when it is dried at a high temperature, or when it is used as a film for retort packaging materials. For example, a case where retort treatment is performed after enclosing cooked foodstuffs when 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, and even more preferably 0.6 to 0.8 dl/g. . If the intrinsic viscosity is less than 0.45 dl/g, sufficient mechanical properties may not be obtained when processed into a molded article.

The polyester resin of the present invention preferably has a glass transition temperature of 0 to 80°C. Also, the crystal melting point is preferably 150 to 250°C.

An example of the method for producing the polyester resin of the present invention is described below.
For example, the acid component and the diol component as described above are used as raw materials, and are subjected to an esterification or transesterification reaction at a temperature of 200 to 260° C. by a conventional method, followed by addition of a polymerization catalyst, an alkali metal compound, and an alkaline earth metal compound. , an organic base-containing compound is added. Then, the polycondensation reaction is carried out under reduced pressure while distilling off excess glycol from the esterified product. Conditions for the polycondensation reaction include, for example, a temperature of 230 to 280° C. under reduced pressure of 5 hPa or less.

The molar ratio (G/A) between the glycol component (G) and the dicarboxylic acid component (A) in the polyester resin raw material is preferably 1.00 to 2.00, more preferably 1.05 to 1.50. When it is less than 1.00, the esterification or transesterification reaction does not proceed sufficiently, and the polycondensation reaction may be difficult to proceed. On the other hand, if it exceeds 2.00, the polycondensation reaction may take a long time.

Furthermore, depending on the purpose and application, an acid component or a diol component may be added to the polymer obtained by the polycondensation reaction, and the depolymerization reaction may be carried out at a temperature of 240 to 280°C.

An organic sulfonic acid compound is used as a polymerization catalyst. Thereby, the obtained polyester resin can contain a sulfur component in an amount within a specific range.
The amount of the organic sulfonic acid compound added is preferably 0.1×10 ⁻⁴ mol or more with respect to 1 mol of the acid component constituting the polyester resin, in order to easily adjust the content of the sulfur component to the above range. , 1×10 ⁻⁴ to 20×10 ⁻⁴ mol.
If the amount of the organic sulfonic acid-based compound added is less than 1×10 ⁻⁴ mol, the sulfur component in the obtained polyester resin may be too small. On the other hand, if it exceeds 20×10 ⁻⁴ mol, the sulfur component in the obtained polyester resin increases, and hydrolysis and thermal decomposition during polymerization are accelerated, resulting in a decrease in polymerizability and a sufficient increase in molecular weight. or the resin itself may not be obtained.

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 acid 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, nithionic acid, nithionic 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 etc. 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, Preferred are 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, the transparency may be inferior, and foreign matter may be generated during melt processing. 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 amount of the alkali metal compound, alkaline earth metal compound and organic base-containing compound to be added is preferably 0.1×10 ⁻⁴ mol or more per 1 mol of the acid component constituting the polyester resin. ⁻⁴ to 40×10 ⁻⁴ mol is more preferable. By setting the amount of these compounds to be added within the above range, the content in the obtained polyester resin can be easily adjusted to a preferable range.

Applications of the polyester resin of the present invention are not particularly limited, but examples thereof include molded articles, fibers, sheets, films, adhesives, and resin solutions.

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 An equal weight mixture of phenol and ethane tetrachloride was used as a solvent for measurement.

(2) Composition of polyester resin Dissolve 10 mg of a sample in 1 mL of a mixed solvent of deuterated chloroform / deuterated trifluoroacetic acid = 9/1 (mass ratio), and use LA-400 type NMR manufactured by JEOL Ltd. ¹ H-NMR was measured, and the molar ratio between each dicarboxylic acid component and each glycol component was calculated from the proton peak integrated intensity of each component in the obtained chart.

(3) Glass transition temperature (Tg)
Using a differential scanning calorimeter Diamond DSC manufactured by PerkinElmer, measurement was performed in a nitrogen stream at a temperature range of 0 to 280°C at a heating rate of 20°C/min.

(4) Content of sulfur component Polyester resin is melt-molded at 300 ° C. to form a disk-shaped molded plate with a diameter of 3 cm × thickness of 1 cm, and a fluorescent X-ray analyzer ZSX Primus manufactured by Rigaku is used to quantify by the calibration curve method. Analysis was carried out.

(5) Contents of Alkali Metal Compound and Alkaline Earth Metal Compound 5 g of the resin composition is placed in a metal crucible, and 2 ml of concentrated sulfuric acid is added to incinerate in an electric furnace. The ash in the crucible was dissolved in a dilute hydrochloric acid aqueous solution and quantified using an ICP-AES analyzer (ICAP6500Duo) manufactured by Thermo Fisher Scientific.

(6) Content of Organic Basic Compound 1 g of the resin composition was dissolved in 10 ml of chloroform and 10 ml of hexafluoroisopropanol (HFIP), and the resulting sample solution was added dropwise to 10 ml of methanol. Subsequently, the precipitated solid content was removed by filtration and dried under reduced pressure, and then 10 ml of a trimethylsilylating agent (HMDS/TMCS/pyridine solution) was added and allowed to stand at room temperature for 1 hour for trimethylsilylation. 50 μl of dibenzyl was added as an internal standard, and measurement was performed using a Shimadzu gas chromatograph (GC-8A).

(7) Intrinsic viscosity retention rate before and after wet heat treatment (40 ° C.) 5 g of the obtained polyester resin and 200 mL of distilled water are placed in a pressure-resistant container with a capacity of 300 mL and heated for 240 hours in a dryer set to a temperature of 40 ° C. Did. In the same manner as in the method (1) above, the retention rate was obtained according to the following formula from the intrinsic viscosity before the wet heat treatment and the intrinsic viscosity after the wet heat treatment.
Retention rate (%) = (intrinsic viscosity after wet heat treatment × 100) / (intrinsic viscosity before wet heat treatment)

(8) Intrinsic viscosity retention before and after wet heat treatment (130°C) The wet heat treatment temperature was changed to 130°C, and the intrinsic viscosity retention was determined in the same manner as in (7) above.

[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 heated and melted esterified product was put into a polycondensation reactor heated to 280° C., and 5-sulfosalicylic acid dihydrate (SS) was added at 2.0×10 ⁻⁴ mol/unit and lithium acetate at 1.0×10 mol/unit. ^-4 mol/unit was added. 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 with stirring under these conditions to obtain a polyester resin. The polyester resin contained 18 ppm catalyst-derived sulfur content and had a Tg of 75.1°C.

Example 2
The heat-melted esterified product was put into a polycondensation reactor heated to 280° C., and 2.0×10 ⁻⁴ mol/unit of 5-sulfosalicylic acid dihydrate (SS) was added. 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. The polycondensation reaction was carried out while stirring under these conditions, and since the predetermined viscosity was reached, the pressure inside the reactor was returned to normal pressure, and 2.0×10 ⁻⁴ mol/unit of lithium acetate was added. While stirring, the system pressure was gradually reduced again to 0.5 hPa or less after 10 minutes. A polycondensation reaction was carried out with stirring under these conditions to obtain a polyester resin. The polyester resin contained 21 ppm catalyst-derived sulfur content and had a Tg of 76.1°C.

Example 3
The heat-melted esterified product was put into a polycondensation reactor heated to 280° C., and 2.0×10 ⁻⁴ mol/unit of 5-sulfosalicylic acid dihydrate (SS) was added. 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. The polycondensation reaction was carried out while stirring under these conditions, and since the predetermined viscosity was reached, the pressure inside the reaction vessel was returned to normal pressure, 4.0 × 10 ^-4 mol/unit of lithium acetate powder was added, and the mixture was stirred for 30 minutes. to obtain a polyester resin. The polyester resin contained 20 ppm catalyst-derived sulfur content and had a Tg of 76.5°C.

Examples 4-35, Comparative Examples 1-3
Except for changing the amount of 5-sulfosalicylic acid dihydrate (SS) added, the type or amount of the alkali metal compound, alkaline earth metal compound, or organic base-containing compound as described in Tables 1 and 2. , the same operation as in Example 1 was performed to obtain a polyester resin.

Example 36
[Polyester resin]
60 parts by mass of the heat-melted esterified product was charged into a polycondensation reactor heated to 250° C., 8 parts by mass of 1,4-butanediol (BD) was added, depolymerization reaction was performed for 1 hour, and then polymerization was performed. As condensation catalysts, 2.0×10 ⁻⁴ mol/unit of 5-sulfosalicylic acid dihydrate (SS) and 2.0×10 ⁻⁴ mol/unit of lithium acetate were added. Next, the temperature of the reactor was brought to 280° C., and the system pressure was gradually reduced to 0.5 hPa or less after 60 minutes. A polycondensation reaction was carried out with stirring under these conditions to obtain a polyester resin. The polyester resin contained 21 ppm catalyst-derived sulfur content and had a Tg of 58.4°C.

Examples 37-53, Comparative Examples 4-7
Except for changing the amount of 5-sulfosalicylic acid dihydrate (SS) added, the type or amount of the alkali metal compound, alkaline earth metal compound, or organic base-containing compound as described in Table 1 or Table 2. , and the same operation as in Example 36 was performed to obtain a polyester resin.

Example 54
[Polyester resin]
43 parts by mass of the heat-melted esterified product was charged into a polycondensation reactor heated to 280° C., 4 parts by mass of ε-caprolactone (εCL) and 15 parts by mass of 1,4-butanediol (BD) were added, and then the mixture was allowed to stand for 1 hour. After performing the depolymerization reaction, 2.0×10 ⁻⁴ mol/unit of 5-sulfosalicylic acid dihydrate (SS) and 2.0×10 ⁻⁴ mol/unit of lithium acetate are used as polycondensation catalysts. was added. 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 with stirring under these conditions to obtain a polyester resin. The polyester resin contained 19 ppm catalyst-derived sulfur content and had a Tg of 34.6°C.

The compositions of the polyester resins obtained in Examples 1-54 and Comparative Examples 1-7 are shown in Table 3 or Table 4, and the evaluation results are shown in Table 5 or Table 6.

In the polyester resins of the present invention obtained in Examples 1 to 54, the ratio of the intrinsic viscosity retention rate when wet heat treated at a temperature of 40 ° C. and a temperature of 130 ° C. is within the range of the present invention. Even so, the hydrolysis was suppressed under high temperature and high humidity, and the heat and humidity resistance was excellent.

On the other hand, the polyester resins obtained in Comparative Examples 1 to 7, which do not contain an alkali metal compound, an alkaline earth metal compound, or an organic base-containing compound, have an intrinsic viscosity when wet heat treated at a temperature of 40 ° C. and a temperature of 130 ° C. The ratio to the retention rate became high, and it was not able to withstand fluctuations in moist heat treatment temperature, and was inferior in moist heat resistance.

Claims (5)

Containing 1 to 500 ppm of sulfur components,
containing one or more compounds selected from an alkali metal compound, an alkaline earth metal compound, and an organic base-containing compound;
Intrinsic viscosity retention rate (A) when wet heat treated under conditions of temperature 40 ° C., relative humidity 100%, 240 hours, and intrinsic viscosity retention when wet heat treated under conditions of temperature 130 ° C., relative humidity 100%, 48 hours A polyester resin characterized in that the ratio (A/B) to the rate (B) is from 1.1 to 4.0.
A fiber made of the polyester resin composition according to claim 1 .
A film comprising the polyester resin composition according to claim 1 .
A molded article comprising the polyester resin composition according to claim 1 .
An adhesive comprising the polyester resin composition according to claim 1 .