JPH069767A - Production of polyester - Google Patents

Abstract

PURPOSE:To obtain a polyester excellent in spinnability, stretchability, etc., while minimizing the amt. of foreign matters accumulating around spinnerets by adding a specified amt. of a phosphonium sulfonate to the reaction system in the process for producing the polyester in the presence of an Sb catalyst. CONSTITUTION:The polyester is produced by adding, to the reaction system, a phosphonium sulfonate of the formula (wherein A is an org. group having no ester-forming group; R1 to R4 are each alkyl or aryl; and n is a positive integer) in an amt. of 10-500mmol% of the total acid component in the process for producing the polyester wherein an arom. dicarboxylic acid and/or its ester- forming deriv. is reacted with an alkylene glycol and/or its ester--forming deriv. to give a glycol ester of the acid and/or its low polymer and the product is polymerized in the presence of an Sb catalyst. Thus is obtd. the polyester excellent in thermal stability and in moldability such as spinnability or stretchability while minimizing the amt. of foreing matters accumulating around spinnerets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester, and more specifically, a polyester having excellent thermal stability and good moldability such as spin-drawing, in particular, very few foreign matters deposited around the spinneret hole during spinning. Manufacturing method.

[0002]

BACKGROUND OF THE INVENTION Polyesters, especially polyethylene terephthalate, have many excellent properties and are therefore widely used in various applications, especially in fibers and films. Such polyesters are usually prepared by esterification of terephthalic acid and ethylene glycol, transesterification of dialkyl terephthalate and ethylene glycol, or reaction of terephthalic acid and ethylene oxide. It is produced by forming a glycol ester and / or a low polymer thereof, and then heating the product under reduced pressure to cause a polycondensation reaction until a predetermined degree of polymerization is reached.

The polyester thus obtained is
Generally, it is put into practical use by extruding it into a fibrous or film shape from a spinning nozzle or a slit in a molten state, and then stretching it. However, the polycondensation reaction proceeds smoothly only by using a catalyst, and a polyester having commercial value can be obtained, but the reaction rate and the quality of the obtained polyester are large depending on the kind of the catalyst used for this. It depends.

Conventionally, as a polycondensation catalyst of polyethylene terephthalate, antimony compounds such as antimony trioxide have an excellent polycondensation reaction accelerating effect, and a polyester having a relatively good color tone can be obtained.
Most widely used. However, the polyester obtained by using such an antimony compound has a drawback that it is inferior in moldability, particularly in spinnability over a long period of time. That is, when a polyester obtained by using an antimony compound as a polycondensation catalyst is melt-spun, after a lapse of time after the start of spinning, a bending phenomenon of the polymer flow (hereinafter referred to as bending) occurs around the outside of a spinning hole, and spinning, Lapping frequently occurs during drawing, and finally spinning itself becomes impossible. Therefore, when bending occurs, it is necessary to replace the spinneret, and production is significantly hindered.

In order to solve the above drawbacks, it has been known that
In order to improve the releasability of the polymer flow from the spinneret, study of a release agent such as silicone, study of the material of the spinneret,
Various measures such as the study of the shape of the spinning hole have been studied. However, the effect was not sufficient.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and its purpose is to:
It is an object of the present invention to provide a method for producing a polyester which has very little foreign matter deposition around the spinneret hole, is excellent in moldability such as spinning drawability, and can be molded without problems in practical production and is excellent in thermal stability.

[0007]

Means for Solving the Problems As a result of intensive studies on bending during melt spinning of polyester in order to achieve the above-mentioned object, the present inventors have found that foreign matter (hereinafter referred to as spinneret) attached and deposited around the spinning hole after the start of spinning. It has been found that there is a close relationship between a foreign substance) and bending, and bending can be prevented by suppressing the adhesion and deposition of the foreign substance on the die.

Further, analysis of foreign matter in the spinneret showed that antimony used as a polycondensation catalyst and thermal degradation products of the polymer were the main components, and during spinning, the antimony compound in the polymer sublimated and adhered to the periphery of the spinneret hole. , It was found that the deteriorated product generated by thermal decomposition of the polymer during spinning exudes and accumulates as a foreign substance on the spinneret.

From these findings, the inventors of the present invention suppress the sublimation of antimony in polyester in order to suppress the accumulation of foreign matter on the die surface, and at the same time improve the thermal stability of the polymer to suppress the production of deteriorated products. It was thought that it was important to do it and repeated examination. As a result, the polyester obtained by adding a specific amount of phosphonium sulfonate at the time of polyester production was found to have extremely few foreign matter on the die surface,
The present invention has been reached.

That is, according to the present invention, a bifunctional aromatic carboxylic acid and / or an ester-forming derivative thereof,
When a polyester is produced by reacting with an alkylene glycol and / or an ester-forming derivative thereof to form a glycol ester of a bifunctional aromatic carboxylic acid and / or a low polymer thereof, and then subjecting it to a polymerization reaction in the presence of an antimony catalyst. A method for producing a polyester is provided, which comprises adding the phosphonium sulfonate represented by the following general formula (I) in an amount of 10 to 500 mmol% with respect to all acid components constituting the polyester.

[0011]

[Chemical 2]

[Wherein A is an organic group having no ester-forming functional group, R ₁ , R ₂ , R ₃ and R ₄ are the same or different groups selected from an alkyl group and an aryl group, and n is a positive group. Indicates an integer. ]

The polyester according to the present invention is mainly intended for a polyester having a difunctional aromatic carboxylic acid as a main acid component and an alkylene glycol as a main diol component. As the bifunctional aromatic carboxylic acid preferably used, for example, terephthalic acid, isophthalic acid,
Examples thereof include naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid, P-oxybenzoic acid, and the like. Examples of the alkylene glycol include ethylene glycol, trimethylene glycol and tetra Methylene glycol etc. can be mentioned. Above all,
A polyethylene terephthalate polyester in which the main acid component is terephthalic acid and the main glycol component is ethylene glycol is preferable. The term "main" as used herein means that a difunctional carboxylic acid other than the difunctional aromatic carboxylic acid and / or a diol component other than the alkylene glycol is 10 mol% or less, preferably 5 mol, based on the total acid component. % Or less may be copolymerized.

Examples of the bifunctional carboxylic acid used here include aliphatic and alicyclic bifunctional carboxylic acids such as adipic acid, sebacic acid, and 1,4-cyclohexanedicarboxylic acid. Examples of the diol compound other than alkylene glycol include cyclohexane-1,4-dimethanol, neopentyl glycol, alicyclic and aromatic diol compounds such as bisphenol A and bisphenol S, and polyoxyalkylene glycol. it can.

Further, within a range where the effect of the present invention is substantially exhibited, isophthalic acid having a sulfonate group such as 5-sodium sulfoisophthalic acid, polycarboxylic acid such as trimellitic acid and pyromellitic acid, and glycerin. A polyol such as trimethylolpropane or pentaerythritol may be used as a copolymerization component.

The polyester can be synthesized by any method. For example, polyethylene terephthalate will be described. Usually, terephthalic acid and ethylene glycol are directly esterified, or a lower alkyl ester of terephthalic acid such as dimethyl terephthalate is transesterified with ethylene glycol, or terephthalic acid and ethylene glycol are used. The reaction of the first step to form a glycol ester of terephthalic acid and / or its low polymer by reacting with oxide, and the reaction product of the first step is heated under reduced pressure in the presence of a polymerization catalyst to obtain a desired degree of polymerization. It is produced by a second stage reaction of polycondensation reaction until

The present invention is directed to the case where an antimony compound is used as a polymerization catalyst used in the reaction in the second step of the above polyester production reaction. In this case, the effect of the present invention is exhibited, that is, the antimony catalyst is used. The generation of foreign matter on the basis of the die is suppressed. Examples of the antimony compound used here include antimony trioxide, antimony pentoxide, antimony acetate, and antimony glycolate, and these may be used alone or in combination of two or more kinds.

The phosphonium sulfonate used in the present invention has the following general formula (I):

[0019]

[Chemical 3]

## STR1 ## wherein A is an ester-forming functional group
Represents an organic group having no group, R₁, R ₂, R₃And R_Four
Is the same selected from the group consisting of an alkyl group and an aryl group.
Or a different group (which may have a substituent), n
Is a positive integer.

Specific examples of the sulfonate anion of the phosphonium sulfonate include (substituted) phenyl sulfonates such as phenyl sulfonate, butyl phenyl sulfonate, octadecyl phenyl sulfonate and dibutyl phenyl sulfonate, naphthyl sulfonate, diisopropyl naphthyl sulfonate, dibutyl naphthyl sulfonate. , Naphthyl sulfonates such as naphthalene disulfonate, butyl sulfonate, octyl sulfonate, lauryl sulfonate, alkyl sulfonates such as hexadecyl sulfonate, and the like,
These may be a mixture.

On the other hand, specific examples of the phosphonium cation include tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, triethylmethylphosphonium, tributylmethylphosphonium, tributylethylphosphonium, trimethylbutylphosphonium, trimethyloctylphosphonium, trimethyllaurylphosphonium and trimethylstearylphosphonium. , Aliphatic phosphonium such as triethyloctylphosphonium and tributyloctylphosphonium, aromatic phosphonium such as triphenylmethylphosphonium, triphenylethylphosphonium, triethylbenzylphosphonium and tributylbenzylphosphonium.

Further, phosphonium having a substituent such as tri (3-hydroxypropyl) methylphosphonium, tri (2-cyanoethyl) methylphosphonium and tributyl (2-hydroxyethyl) phosphonium can be mentioned.

The above-mentioned phosphonium sulfonate salt may be added to the polyester at a stage before completion of the above-mentioned polyester synthesis, preferably at a stage after completion of the first stage reaction. The addition amount of the phosphonium sulfonate salt needs to be 10 to 500 mmol% with respect to all the acid components constituting the polyester. Addition amount is 1
When it is less than 0 mmol%, the effect of suppressing the production of foreign matter in the die of the polyester obtained is small, while on the other hand, it is 500 mmol%.
If it exceeds the above, not only the thermal stability of the obtained polyester is deteriorated and the effect of suppressing the foreign substance from the die is lowered, but also the polycondensation reaction rate is slowed and the color tone of the obtained polymer is deteriorated, which is preferable. Absent.

The polyester according to the present invention described above may be added with optional additives such as an ether bond inhibitor, a stabilizer, an anti-coloring agent, a heat-resistant agent, a flame retardant, an antioxidant and a matting agent, if necessary. Agents, colorants, inorganic fine particles and the like may be contained.

[0026]

By the production method of the present invention described in detail above, a polyester having excellent thermal stability and good moldability such as spinning / drawing can be obtained, in particular, the deposition of foreign matter on the spinneret face is small. The reason has not been clarified yet, but it is presumed as follows.

That is, the transesterification reaction catalyst and / or polycondensation reaction catalyst added at the time of polyester production reacts with the phosphonium sulfonate compound, and the sublimability of the antimony catalyst is suppressed, and its activity is suppressed appropriately. The color tone of the polymer becomes good. As a result, it is presumed that when melt spinning is performed, polymer deterioration products or antimony catalysts are less likely to be deposited around the spinneret holes.

Therefore, the polyester according to the present invention can be stably molded under arbitrary molding conditions.
For example, upon spinning, a method of spinning at a speed of 500 to 2500 m / min, stretching and heat treatment, 1500 to 500
A method in which spinning is performed at a speed of 0 m / min, and drawing and false twisting are performed simultaneously or subsequently, spinning is performed at a high speed of 5000 m / min or more,
Depending on the application, arbitrary spinning conditions such as a method of omitting the drawing step are adopted, and stable spinning can be performed.

Also, when forming a film or a sheet, a method of imparting anisotropy by applying tension only in one direction after film formation, a method of stretching simultaneously or in two or more directions in two or more steps, Any condition such as the method of multi-stage stretching can be adopted without any trouble, and its industrial significance is extremely large.

[0030]

EXAMPLES The present invention will be described in more detail below with reference to examples.
The parts in the examples represent parts by weight, and the measured values were according to the following methods.

The intrinsic viscosity [IV] of the polymer was determined from the value measured with an orthochlorophenol solution at 35 ° C.

The spinnability was measured by using a spinneret having 30 spinning holes with a diameter of 0.3 mm and spinning at a discharge rate of 80 g / min and a winding speed of 1200 m / min for 7 days, and foreign matter around the spinning holes was Of the unstretched yarn obtained as described above, the stretching temperature is 85 ° C., the stretching ratio is 3.5 times, and the stretching speed is 110.
The wrap ratio was obtained when the filament was drawn at 0 m / min and wound into 25 kg of 150 denier / 30 filament.

[0033]

Examples 1 to 8 and Comparative Examples 1 to 3 100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, manganese acetate 4
Water salt 0.031 part (0.
(025 mol%) was charged into a transesterification can, and the transesterification reaction was performed while distilling out the produced methanol by raising the temperature from 140 ° C. to 220 ° C. over 3 hours in a nitrogen gas atmosphere.

Next, 0.097 parts of trimethyl phosphate as a stabilizer and phosphonium sulfonate as shown in Table 1 were added, and then the temperature rising / expulsion of excess ethylene glycol was started. After 10 minutes, 0.04 part of antimony trioxide (0.027 mol% based on dimethyl terephthalate) was added as a polycondensation reaction catalyst. When the internal temperature reached 240 ° C., the expulsion of ethylene glycol was completed and the reaction product was transferred to the polymerization vessel.

Then, the reaction was carried out at normal pressure for 30 minutes while raising the temperature, and then the pressure was reduced from 760 mmHg to 1 mmHg over 1 hour.
At the same time, the internal temperature was raised to 290 ° C. over 1 hour and 30 minutes. When the polymerization was further continued for 2 hours at a polymerization temperature of 290 ° C. under a reduced pressure of 1 mmHg or less, the vacuum was broken with nitrogen gas to terminate the polymerization reaction, and the polymer was discharged at 290 ° C. under the pressure of nitrogen gas. The evaluation results of the quality and spinnability of the obtained polymer are as shown in Table 1.

[0036]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location D01F 6/62 F 7199-3B

Claims (1)

[Claims] 1. A bifunctional aromatic carboxylic acid and / or an ester-forming derivative thereof is reacted with an alkylene glycol and / or an ester-forming derivative thereof to form a glycol ester of a bifunctional aromatic carboxylic acid and / or When the low polymer is produced and then subjected to a polymerization reaction in the presence of an antimony catalyst to produce a polyester, a phosphonium sulfonate represented by the following general formula (I) is added to the total acid component constituting the polyester in an amount of 10 to 10: 5
A method for producing a polyester, which comprises adding 100 mmol%. [Chemical 1] [Wherein A is an organic group having no ester-forming functional group, R is
₁ , R ₂ , R ₃ , and R ₄ are the same or different groups selected from an alkyl group and an aryl group, and n is a positive integer. ]