JPH0319860B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyester, and more particularly, to a method for producing polyester suitable for producing fibers having special micropores communicating from the inside to the surface. Polyester has many excellent properties and therefore has an extremely wide range of uses as a synthetic fiber. However, since polyester fibers are hydrophobic, their use in fields where water absorption and hygroscopicity are required is severely restricted. Conventionally, as a method of imparting water absorbency or hygroscopicity to polyester fibers, a method has been proposed in which a hydrophilic compound, such as polyalkylene glycol or polyalkylene glycol and an organic sulfonic acid metal salt is blended with polyester before forming it into fibers. ing. However, the fibers obtained by this method do not have sufficient water absorption or hygroscopicity, and their durability easily decreases due to washing, etc., and their properties such as light resistance and heat resistance also decrease. There is. In addition, by treating polyester fibers obtained by blending polyalkylene glycol and organic sulfonic acid metal salts with an aqueous alkaline solution, wrinkle-like micropores arranged in the fiber axis direction are formed on the fiber surface, resulting in water absorption properties. Methods to improve this have also been proposed. However, the polyester fibers obtained by this method have a significant decrease in strength and are extremely susceptible to fibrillation, so they are not suitable for practical use. The inventor of the present invention has conducted intensive studies to provide a polyester fiber with excellent water absorption and hygroscopicity without the above-mentioned drawbacks, and as a result, the following general formula [] [In the formula, Ar is a benzene ring or a naphthalene ring,
R is -COOR' (however, R' is a hydrogen atom, with 1 to 1 carbon atoms)
4 alkyl group or aryl group) or -CO[-O
(-CH ₂ )l]-pOH (where, l is an integer of 2 or more, p
is an integer of 1 or more), M and M' represent an alkali metal or an alkaline earth metal, m is 0 or 1, n is an integer of 1 to 5, and m+n is an integer of 1 to 5. ] Polyester blended with a specific amount of a specific compound represented by is used to form solid or hollow fibers,
By treating these fibers with an aqueous alkaline solution, they are scattered in the cross section of the fibers and arranged in the fiber axis direction.
In addition, it is possible to form micropores in which at least a portion of the fibers communicates from the inside or hollow part to the surface, thereby providing excellent water absorption, hygroscopicity, and durability. It was discovered that polyester fibers with strength and fibrillation resistance sufficient for practical use could be obtained, and this was proposed earlier.
However, the compound represented by the above general formula [] has the disadvantage that it tends to generate coarse agglomerated particles in polyester, tends to cause pack clogging during spinning, and often breaks during spinning and stretching. I learned that. The inventor of the present invention continued to study in an attempt to produce a polyester in which the compound represented by the above general formula [] is finely dispersed without such drawbacks, and found that when adding the above general formula [], a specific amount of 3. , 5-di(carbomethoxy)benzenesulfonic acid Na was found to be mixed and added to achieve the above object. The present invention was completed as a result of further studies based on this knowledge. That is, the present invention produces a polyester by reacting a difunctional carboxylic acid, mainly terephthalic acid, or its ester-forming derivative with a glycol, mainly alkylene glycol having 2 to 6 carbon atoms, or its ester-forming derivative. In doing so, at any stage until the completion of the production reaction, the following general formula [] is added in an amount of 0.1 to 25 mol% based on the bifunctional carboxylic acid component. [Wherein, Z is an aromatic ring or an aliphatic hydrocarbon group,
X is

【formula】

【formula】

[Formula] (-CH ₂ )a-OH, -O(CH ₂ )b[-O(CH ₂ )b]-dOH or

[Formula] (wherein, R'' is an alkyl group or aryl group having 1 to 4 carbon atoms, a is an integer of 1 or more, b is an integer of 2 or more, d is an integer of 0 or 1 or more), Y is X M″ represents an alkali metal or an alkaline earth metal. ] 5 for the compound A represented by and the compound A
The following general formula [] in an amount of ~500 mol% In the formula, Z is an aromatic ring or an aliphatic hydrocarbon group,
teeth

【formula】

【formula】

[Formula] (-CH ₂ )a-OH, -O(CH ₂ )b[-O(CH ₂ )b]-dOH or

[Formula] (wherein, R'' is an alkyl group or aryl group having 1 to 4 carbon atoms, a is an integer of 1 or more, b is an integer of 2 or more, d is an integer of 0 or 1 or more), Y is X M″ represents an alkali metal or an alkaline earth metal. ] This is a method for producing polyester, characterized in that compound B represented by the following is mixed in advance and added. The polyester used in the present invention has terephthalic acid as the main acid component, and is selected from alkylene glycols having 2 to 6 carbon atoms, such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, and hexamethylene glycol, particularly preferably ethylene glycol. The main target is polyester that can be molded into fibers, films, and other molded products whose main glycol component is at least one glycol selected from , tetramethylene glycol, and tetramethylene glycol. It may also be a polyester in which part of the terephthalic acid component is replaced with another difunctional carboxylic acid component, and/or a polyester in which part of the glycol component is replaced with a diol component other than the above-mentioned glycol. good. Examples of difunctional carboxylic acids other than terephthalic acid used here include isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid,
Aromatic, aliphatic, and alicyclic difunctional carboxylic acids such as diphenoxyethanedicarboxylic acid, β-oxyethoxybenzoic acid, p-oxybenzoic acid, adipic acid, sebacic acid, and 1,4-cyclohexanedicarboxylic acid. can be given. Examples of diol compounds other than the above-mentioned glycols include aliphatic, alicyclic, and aromatic diol compounds such as cyclohexane-1,4-dimethanol, neopentyl glycol, bisphenol A, and bisphenol S. can. Such polyesters may be synthesized by any method. For example, regarding polyethylene terephthalate, it is usually done by directly esterifying terephthalic acid and ethylene glycol, by transesterifying a lower alkyl ester of terephthalic acid such as dimethyl terephthalate with ethylene glycol, or by transesterifying terephthalic acid and ethylene glycol. The first stage reaction is to react with ethylene oxide to produce a glycol ester of terephthalic acid and/or its low polymer, and the first stage reaction product is heated under reduced pressure to reach the desired degree of polymerization. It is produced by a second step of polycondensation reaction. The following general formula showing the compound A used in the present invention [] Among them, Ar is a benzene ring or a naphthalene ring.
R is -COOR' (however, R' is a hydrogen atom, with 1 to 1 carbon atoms)
4 alkyl group or aryl group) or -CO[-O
[-CH ₂ )l] _-p OH (where, l is an integer of 2 or more, p
is an integer greater than or equal to 1). M and M' are alkali metals or alkaline earth metals, especially
Particularly preferred are Li, Na, K, Ca1 _/2 , Mg1 _/2 , and Ba1 _/2 . Further, M and M' may be the same or different. m is an integer of 0 or 1, n is an integer of 1 to 5, and m+n is an integer of 1 to 5, where m is 0 or 1, n is an integer of 1 to 2, m+n
is preferably an integer of 1 to 2. Preferred specific examples of such compound A include 3
-Carbomethoxybenzenesulfonic acid Na-5
-Sodium carboxylate, Sodium 3-carbomethoxybenzenesulfonic acid, Potassium 5-carboxylate, K 3-carbomethoxybenzenesulfonic acid, Potassium 5-carboxylate, Na-5-carboxylic acid 3-hydroxyethoxycarbonyl benzenesulfonate Na acid, 3-carboxy benzenesulfonic acid Na-5-carboxylic acid Na3-carbomethoxybenzenesulfonic acid
Na-5-carboxylic acid Mg _1/2 , 3-hydroxyethoxycarbonyl benzenesulfonic acid Na-5-
Carboxylic acid Mg _1/2 , benzenesulfonic acid Na-3,
5-di(sodium carboxylate), benzenesulfonic acid
Na-3,5-di(Mg _1/2 carboxylic acid), Na-3-carboxylic acid Na-benzenesulfonic acid, Na-7-carbomethoxy naphthalene-1-sulfonic acid
- Sodium carboxylate, naphthalene-1-sulfonic acid
Na-3,7-di-(carboxylic acid Mg _1/2 ), 3-hydroxycarbonyl benzenesulfonic acid Ca _1/2 −
5-carboxylic acid Li, benzenesulfonic acid Na-3,
5-di(carboxylic acid Ba _1/2 ), benzenesulfonic acid K-3,5-di(carboxylic acid Ca _1/2 ) benzenesulfonic acid Na-m-carboxylic acid Mg _1/2 , 2-hydroxyethoxybenzenesulfone acid Mg _1/2 -5-carboxylic acid K, 3-hydroxydi(ethyleneoxy(benzenesulfonic acid Li-5-carboxylic acid Ca _1/2 ,
Naphthalene-2-carboxylic acid K-6-sulfonic acid K, naphthalene-2,6-di(carboxylic acid)
Mg _1/2 )-4-sulfonic acid Na, 6-hydroxyethoxynaphthalene-2-carboxylic acid Mg _1/2 -4-
Examples include sodium sulfonate. Compound A may be used alone or in combination with two
More than one species may be used in combination. It may be added at any stage before the end of the polyester synthesis reaction, for example, it may be added and mixed into the polyester raw materials, it may be added during the first step reaction of the polyester synthesis described above, or it may be added at any stage before the completion of the polyester synthesis reaction. It may be added during the two-step reaction. If the amount of compound A added is too small, the water absorbency and hygroscopicity of the polyester fiber etc. finally obtained will be insufficient, and if it is too large, coarse agglomerated particles will be formed even by the method of the present invention. and reeling,
Inhibits film forming properties. Therefore, the amount added should be 0.1 to 0.1 to the acid component that constitutes the polyester to be added.
Should be in the range of 25 mol%, 0.3-15 mol%
A range of 0.5 to 5 mol% is particularly preferred. In addition, the following general formula showing compound B used in combination with compound A [] where Z is an aromatic ring or an aliphatic hydrocarbon group,
Among these, aromatic rings are preferred, and benzene rings or naphthalene rings are particularly preferred. X is

【formula】 【formula】

[Formula] (-CH ₂ ) a-OH, -O(CH ₂ ) _b [-O(CH ₂ ) _b ] - _d
Oh,

[Formula] (where R'' is an alkyl group or aryl group having 1 to 4 carbon atoms, a is 1
b is an integer of 2 or more, and d is an integer of 0 or 1 or more). Y represents a functional group that is the same as or different from X, or a hydrogen atom. M'' is an alkali metal or an alkaline earth metal.Among such compounds B, particularly preferred examples include 3,
5-di(carbomethoxy)benzenesulfonic acid
Na (or K), 3,5-di(carboxy)benzenesulfonic acid Na (or K), 3,5-di(hydroxyethoxycarbonyl)benzenesulfonic acid
Na (or K), 3,7-di(carbomethoxy)naphthalene-1-sulfonic acid Na (or K), 2,5
-Bis(hydroxyethoxy)benzenesulfonic acid Na (or K) 3,5-di(carbomethoxy)benzenesulfonic acid Ca _1/2 , 2,5-di(hydroxyethoxy)benzenesulfonic acid Na, 2-hydroxydi( Ethyleneoxy)-5-hydroxyethoxycarbonylbenzenesulfonic acid K, 2,6
-Di(carbomethoxy)naphthalene-4-sulfonic acid Ba, 2,2-bis(4-hydroxyphenyl)propane monosulfonic acid Li salt, dimethyl
Examples include sodium sulfosuccinate. Compound B needs to be mixed in advance with compound A before being added. Compound B in solution, slurry, or solid form is mixed in advance with compound A in solution, slurry, or solid form, and then added. In particular, it is preferable to add it as a mixed solution of glycol. If Compound B is added separately from Compound A without being mixed with Compound A in advance, the dispersibility of Compound A cannot be improved. Compound B may be used alone or in combination with two
More than one species may be used in combination. If the amount added is too small, the effect of suppressing the generation of coarse agglomerated particles of compound A will be insufficient, and if it is too large, the heat resistance and light resistance of the final polyester will deteriorate. , should be in the range of 5 to 500 mol % based on the added sulfonic acid metal salt,
A range of 30 to 200 mol% is preferred. Note that the polyester obtained by the method of the present invention may contain optional additives, such as catalysts, color inhibitors, heat resistant agents, flame retardants, fluorescent brighteners,
A dissipating agent, a coloring agent, countless fine particles, etc. may be included. Further explanation will be given below with reference to Examples. Parts in the examples indicate parts by weight, and the number of coarse aggregated particles in the resulting polyester was measured by the following method. (Method for measuring the number of coarse agglomerated particles) Approximately 2 mg of a polyester sample was accurately weighed and melted and pressed into a circular thin film with a diameter of approximately 1 cm between two cover glasses to create a preparamate, which was then measured using an optical microscope. The total number of coarsely aggregated particles having a diameter of 10 μm or more was counted, and the number of coarsely aggregated particles was determined according to the following formula. Number of coarsely aggregated particles = total number of coarsely aggregated particles/sample weight (pieces/
mg) Example 1 100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, and 0.06 parts of calcium acetate monohydrate are placed in a transesterification tank, and the temperature is raised from 140°C to 230°C over 4 hours under a nitrogen gas atmosphere to generate the product. The transesterification reaction was carried out while methanol was distilled out of the system. The resulting product was then treated with trimethyl phosphate.
0.06 parts of antimony trioxide and 0.04 parts of antimony trioxide were added, and further 4 parts of a 25% ethylene glycol solution of sodium 3-hydroxyethoxycarbonylbenzenesulfonate-5-carboxylic acid and 3,5-di(hydroxyethoxycarbonyl)benzenesulfone were added. Acid Na 25
A mixed solution of 2 parts of % ethylene glycol solution (molar ratio 1:0.427) was added and transferred to a polymerization can. Next, the pressure was reduced from 760 mmHg to 1 mmHg over 1 hour.
At the same time, the temperature was raised from 230°C to 280°C over 1 hour and 30 minutes. Under reduced pressure of 1 mmHg or less, the polymerization temperature was 280°C for an additional 2 hours and 30 minutes, for a total of 4 hours, and the intrinsic viscosity was
A polymer with a softening point of 0.640 and a softening point of 259°C was obtained. The number of coarse aggregated particles in this polymer was 1/mg. Example 2 4 parts of a 25% ethylene glycol solution of Na-5-carboxylic acid Na 3-hydroxyethoxycarbonylbenzenesulfonate used in Example 1 and 3,5-di(hydroxyethoxycarbonyl)
Instead of a mixed solution of 2 parts of 25% ethylene glycol solution of sodium benzenesulfonate, 20% of sodium benzenesulfonate-3,5-di(carboxylic acid Mg _1/2 )
The same procedure as in Example 1 was carried out except that a mixed slurry of 5 parts of ethylene glycol slurry and 4.9 parts of a 25% ethylene glycol solution of Na 3,5-di(hydroxyethoxycarbonyl)benzenesulfonate (molar ratio 1:1) was added. A polymer with an intrinsic viscosity of 0.660 and a softening point of 258°C was obtained. The number of coarse aggregated particles in this polymer was 0.5 particles/mg. Example 3 100 parts of dimethyl terephthalate, 3-carbomethoxybenzenesulfonic acid Na-5-carboxylic acid
Ethylene glycol solution containing 5 parts of Mg _1/2 and 7 parts of Na 3,5-dicarbomethoxybenzenesulfonate
72 parts of manganese acetate tetrahydrate and 0.04 parts of manganese acetate tetrahydrate were placed in a transesterification tank, and 140
The transesterification reaction was carried out while raising the temperature from °C to 230 °C and distilling the generated methanol out of the system. Subsequently, 0.04 part of a 56% aqueous solution of orthophosphoric acid and 0.04 part of antimony trioxide were added to the obtained product, and the mixture was transferred to a polymerization vessel. Next, the pressure was reduced from 760 mmHg to 1 mmHg over 1 hour, and at the same time the pressure was reduced to 230 mmHg over 1 hour and 30 minutes.
The temperature was raised from ℃ to 280℃. Under reduced pressure of 1 mmHg or less, at a polymerization temperature of 280°C for an additional 2 hours, totaling 3 hours30
Partial polymerization was performed to obtain a polymer with an intrinsic viscosity of 0.508 and a softening point of 251°C. The number of coarse aggregate particles in this polymer is 2
number/mg. Comparative Example 1 3,5-di(hydroxyethoxycarbonyl)benzenesulfonic acid used in Example 1
The process was carried out in the same manner as in Example 1 except that the 25% Na ethylene glycol solution was not added, and the intrinsic viscosity was 0.645.
A polymer with a softening point of 262°C was obtained. The number of coarse aggregated particles in this polymer was 12/mg. Comparative Example 2 3,5-di(hydroxyethoxycarbonyl)benzenesulfonic acid used in Example 2
The process was carried out in the same manner as in Example 2 except that the 25% ethylene glycol solution of Na was not added, and the intrinsic viscosity was 0.643.
A polymer with a softening point of 260°C was obtained. The number of coarse aggregated particles in this polymer was 20 particles/mg. Comparative Example 3 The same procedure as in Example 3 was conducted except that 7 parts of Na 3,5-di(carbomethoxy)benzenesulfonic acid used in Example 3 was not used, and the intrinsic viscosity was
0.640 and a softening point of 259°C was obtained. The number of coarse aggregated particles in this polymer was 40 pieces/mg. Examples 4-9 3 used as compound B in Example 3,
The same procedure as in Example 3 was carried out except that the compounds listed in Table 1 were used in place of Na 5-dicarbomethoxybenzenesulfonate. The intrinsic viscosity, softening point, and number of coarse agglomerated particles of the polymer were as shown in Table 1.

[Table] Examples 10 to 16 3- used as compound A in Example 1
The same procedure as in Example 1 was carried out except that the compounds listed in Table 2 were used in place of Na-5-carboxylic acid Na-hydroxyethoxycarbonylbenzenesulfonate.
The results are shown in Table 2.

[Table] Example 17 3,5-di(hydroxyethoxycarbonyl)benzenesulfonic acid used in Example 1
m- instead of 25% ethylene glycol solution of Na.
The same procedure as in Example 1 was conducted except that a 25% ethylene glycol solution of sodium carboxybenzenesulfonate was used. The intrinsic viscosity of the polymer was 0.548, the softening point was 261°C, and the number of coarse aggregated particles was 2/mg. Example 18 Hollow fibers (75 denier/24 filaments) with a hollow ratio of 20% were created from the polymers obtained in Examples 1 to 17 in accordance with a conventional method, and then the obtained hollow fibers were knitted into a stockinette fabric. After a further 20% alkali weight loss treatment, the water absorption rate and water absorption rate were measured by the following method. A test cloth was prepared in the same manner as above using ordinary polyethylene terephthalate as a reference sample, and the water absorption rate and water absorption rate after the alkali weight loss treatment were measured. The results are shown in Table 3. <Water absorption rate test method> (according to JIS-L1018) The fabric was washed with a 0.3% aqueous solution of detergent Zabu (manufactured by Kao Corporation) for a specified number of times at 40°C for 30 minutes, then dried. The obtained sample is placed horizontally, one drop of water (0.04 cc) is dropped from a height of 1 cm above the sample, and the time until the water is completely absorbed by the sample and no reflected light is observed is measured. <Water Absorption Measurement Method> A sample obtained by completely drying a fabric is immersed in water for 30 minutes or more, and then dehydrated for 5 minutes in a dehydrator of a household electric washing machine. It is determined by the following formula from the weight of the bone-dried sample and the weight of the sample after dehydration. Water absorption rate = (sample weight after dehydration - bone dry sample weight) / bone dry sample weight x 100 (%)

【table】

Claims (1)

[Scope of Claims] 1. A polyester produced by reacting a bifunctional carboxylic acid, mainly terephthalic acid, or its ester-forming derivative with a glycol, mainly alkylene glycol having 2 to 6 carbon atoms, or its ester-forming derivative. In producing the following general formula [] in an amount of 0.1 to 25 mol% based on the bifunctional carboxylic acid component at any stage until the production reaction is completed. [In the formula, Ar is a benzene ring or a naphthalene ring,
R is -COOR' (however, R' is a hydrogen atom, with 1 to 1 carbon atoms)
4 alkyl group or aryl group) or -CO[-O
(-CH ₂ )l]-pOH (where, l is an integer of 2 or more, p
is an integer of 1 or more), M and M' represent an alkali metal or an alkaline earth metal, m is 0 or 1, n is an integer of 1 to 5, and m+n is an integer of 1 to 5. ] 5 for the compound A represented by and the compound A
The following general formula [] in an amount of ~500 mol% [Wherein, Z is an aromatic ring or an aliphatic hydrocarbon group,
X is [Formula] [Formula] [Formula] (-CH ₂ )a-OH, -O(CH ₂ )b[-O(CH ₂ )b]-dOH or [Formula] (where R″ is the number of carbon atoms 1 to 4 alkyl or aryl groups, a is an integer of 1 or more, b is an integer of 2 or more, d is an integer of 0 or 1 or more), Y is the same or different functional group or hydrogen atom as X, M '' indicates an alkali metal or an alkaline earth metal. ] A method for producing polyester, characterized in that compound B represented by the following is mixed in advance and added.