JPS5896624A - Manufacture of polyester - Google Patents

Abstract

PURPOSE:To obtain a high-orientation degree and low-crystallinity polyester suitable for high-speed spinning, by the reaction between a bifunctional carboxylic acid such as terephthalic acid and a glycol in the presence of each specific metallic compound and a carboxylic acid anhydride. CONSTITUTION:In manufacturing a polyester by the reaction between a bifunctional carboxylic acid (consisting mainly of terephthalic acid) or its dimethyl ester and a glycol, each preferably amount between 1 and 200 millimol%, based on the bifunctional carboxylic acid, of (A) a metal alcoholate (e.g. sodium methylate) or a carboxylic acid metal salt (e.g. sodium acetate) and (B) a carboxylic acid anhydride having methylene group at its alpha-site (e.g. acetic anhydride, propionic anhydride) are incorporated in the reaction system pref. prior to the initiation of a pressure reduction, to obtain the objective polyester.

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 high speed spinning.

Polyester fibers, especially polyalkylene terephthalate, have many excellent properties.

It is used in a wide range of fields such as films and resins.

Among them, polyesters represented by polyethylene terephthalate are most widely used in large quantities in the textile field.

Conventionally, in order to produce processed yarns of polyester fibers, such as polyester filaments, the mainstream method has been to perform spinning, grinding, and pre-combustion processing in separate steps. However, in recent years, by increasing the spinning speed, intermediate bacteriostatic undrawn yarns have appeared, and the so-called POY-DTY method, in which drawing and false twisting are performed in one continuous stage, has come to be practiced. This method makes it possible to improve the productivity and shorten the process of manufacturing polyester filament processed yarn, and is also excellent from the viewpoint of reducing manufacturing costs, and will become the mainstream of future yarn spinning technology.

However, as the speed of spinning technology increases, various problems have arisen. For example, if the spinning speed is 250011/min or more, 4? When finishing at high speeds of ksooom/min or higher, yarn breakage often occurs during spinning.

Changes in the quality of the thread-splitting process during drawing and false twisting, and occurrence of fuzz in the resulting processed thread, resulting in a decrease in strength.

Problems such as quality deterioration such as the occurrence of dye spots have occurred, and it has been extremely difficult to sufficiently improve productivity by increasing the spinning speed.

Various studies have been carried out as a countermeasure for the problem of stiffness.

For example, attempts have been made to optimize spinning conditions such as spinning hot water temperature, cooling air flow rate and temperature, and to modify spinning cylinders, spinning rods, etc., but no sufficient improvement has been achieved. Modifications of polyesters are also being considered, including polyalkylene/glycols such as diethylene glycol and polyoxyethylene glycol, compounds with sulfonate groups, and chain branching agents such as pentaerythritol, trimellitic acid, and trimethylolpropane. Many attempts have been made, including polymerization and addition of metal species such as kaolinite, calcium and lithium. However, the improvement method by copolymerization is accompanied by a decrease in the excellent properties of polyester, and the addition of metals such as calcium and lithium causes foreign matter in the polymer, resulting in increased spinning pack pressure and foreign matter accumulation around the spinneret. It is difficult to say that this is a desirable countermeasure as it also induces undesirable phenomena.

The present inventors investigated the conditions for preventing such drawbacks and achieving high productivity even in the high speed spinning range and no quality value. Factors based on its microstructure, such as degree, are silk miller 8Ai1! It has been found that the most advantageous conditions for productivity and quality are that the resulting spun yarn has a high degree of orientation and a low degree of crystallinity. Based on this knowledge, we conducted intensive research to provide a polyester that could yield spun yarn with a high degree of orientation and a low degree of crystallinity in the high-speed spinning range. It was discovered that the above object could be achieved by adding , and this led to the present invention.

That is, the present invention involves reacting a difunctional carboxylic acid mainly consisting of terephthalic acid or its dimethyl ester with at least one type of glyfur, and then condensing the reaction product to produce a polyester. At any stage until the production reaction is completed, (a) at least one metal compound selected from metal alcoholades and carboxylic acid gold maple salts, and (b) a carboxylic acid anhydride having a methylene group at the α-position. This is a method for producing polyester characterized by adding at least one type of polyester.

The polyester referred to in the present invention is mainly polyalkylene terephthalate obtained from ten-heptatalic acid or its dimethyl ester and fullkylene glycol.
Fullylene glycol of No. 6 is preferred, and among them, ethylene glycol, trimethylene glycol, and tetramethylene glycol are particularly preferred. Also, as a third component, a difunctional carboxylic component other than terephthalic acid and/or an alkylene glycol as the main component. Polyester copolymerized with other diol compounds may also be used.

For K to produce such polyester, a simple esterification method or a transesterification method is employed.

For example, to explain polyethylene terephthalate, terephthalic acid or dimethyl terephthalate and ethylene glycol are heated to cause an esterification or transesterification reaction while distilling off the generated water or methanol, and the resulting reaction product is heated under reduced pressure. It is produced by a method of carrying out a polycondensation reaction until a desired degree of polymerization is achieved. It should be noted that a catalyst can be used in this production reaction depending on the membership fee, and the present invention can achieve greater effects particularly when an anti-septane compound is used as a polycondensation catalyst.

Examples of the metal flucorate used in the present invention include sodium methylate, sodium ethylate, potassium methylate, potassium ethylate, sodium benzilade, aluminum ethylate, and the like. Examples of carboxylic acid metal salts include sodium acetate.

Potassium acetate, manganese acetate, calcium acetate.

Magnesium acetate, sodium purpionate.

Metal salts of aliphatic carboxylic acids such as potassium phenylacetate, metal salts of aromatic carboxylic acids such as sodium benzoate, sodium toluate, (mono- or di)sodium terephthalate, potassium glycolate, p-oxybenzoic acid Examples include metal rings of oxycarboxylic acids such as sodium, calcium m-oxybenzoate, monopotassium tartrate, and sodium citrate.

These metal compounds may be used alone or in combination of two or more.

The amount of such a metal compound to be used in combination with the carboxylic acid anhydride described later can be used in an extremely small amount to obtain the desired spun yarn with high sterility and low crystallinity. It is preferable to use 1 mm or more per difunctional carboxylic acid component. Further, there is no need to particularly limit the upper limit of the amount, but if the amount is too large, the polyester may be colored, foreign matter may be generated, or the softening point may be lowered, so it is preferably 200 millimoles or more.

Examples of carbonic acid anhydrides having a methylene group at the α-position to be used in combination with the above metal compounds include acetic anhydride, sorpion anhydride, and succinic anhydride.

Phthalic anhydride, valeric anhydride, M1 anhydride, maleic anhydride, phenyl acetate anhydride can be used. These carboxylic acid anhydrides may be used alone or in combination of two or more kinds.

The use of such carbonic acid anhydride 1 makes it possible to obtain a spun yarn with the desired degree of orientation and low crystallinity with a small amount of powder, but it is difficult to obtain a spun yarn with a low degree of crystallinity and the desired degree of orientation with a small amount of powder. It is preferable to use lj rimorti or more. There is no need to particularly limit the upper limit of the amount, but if the amount is too large, coloring or foreign matter will occur in the polyester, so it is preferably less than 200 J rimorti, and the timing of addition of the metal compound and carbonic acid anhydride should be adjusted before the polycondensation process. It may be added at the time of collapse as long as it is before the reaction is completed, but it is preferable to add it before the beginning of polycondensation, specifically before the sand average degree of polymerization of the polymer reaches 30, and especially before the start of decompression. is preferred. The addition means may be arbitrary. For example, the additive may be added as it is, may be added as a solution or slurry of GLYF-/L, or may be added as an aqueous solution.

The spinning speed of the polyester obtained by K in this manner is 25
Even if the yarn is spun in a far range of 00rn/min or more, especially aoooom/min or more, the degree of orientation is high and the crystallinity is good, and the spun yarn can be easily produced without causing any trapping such as yarn breakage. The speed can be further increased, and productivity can be further increased.Also, there is less variation in the degree of fiber orientation and crystallinity of the resulting spun yarn, and there are no problems during processing. In addition, the final processed yarn has a stable quality with less variation in dyeing unevenness.

Furthermore, since the crystallinity of the polyester can be controlled according to the present invention, it is extremely suitable for general molding applications other than fibers and resin applications.

In addition, various additives such as an antistatic agent, an easy-to-dye agent, a coloring agent, etc. may be mixed and added to the polyester obtained by the method of the present invention, if necessary, in combination with an ether formation inhibitor, a crystallizing agent. can be adopted without any problem.

Next, the present invention will be explained in detail with reference to Examples.

Parts in the examples indicate parts by weight, and symbols and measurement methods used in the examples are explained in ).

[η): Intrinsic viscosity determined from the viscosity of the polymer measured in an orthochlorophenol solvent at 30°C.

col-L, cal-b: represents the hue of the polymer.

It was measured using a Hunter type color difference meter.

The larger the value of col-L, the higher the whitening of the polymer;
The larger the value of lb, the stronger the yellowness of the polymer.

△n: indicates the degree of orientation of the spun yarn, Berek
It was measured by the method.

Spring water shrinkage (BWS): The degree of crystallinity of the fiber was expressed as spring water shrinkage (BWS) determined by the following formula.

The larger the value of spring water shrinkage (BWS), the lower the degree of crystallinity.

Lo: Tightness and slenderness of the spun yarn obtained by high-speed spinning Lf: Fiber length after holding the obtained spun yarn in boiling water for 30 minutes Example 1 and Comparative Examples 970 parts of dimethyl terephthalate, 640 parts of ethylene glycol , manganese acetate 031 as transesterification catalyst
1 part, sodium acetate 0.17 part and acetic anhydride 0.13 part are charged into a reactor equipped with a stirrer, a rectification column and a condenser, heated from 140°C to 230°C, and the methanol produced is distilled out of the system. A transesterification reaction was carried out.

When the internal temperature reached 230°C, 0.18 parts of trinolotylphosphny was added as a stabilizer, and 10 minutes later, 0.4 parts of antimony trioxide and! After adding titanium dioxide 291s as an i5 oil agent, the mixture was transferred to a polymerization pot equipped with a stirrer and a glycol distillation stabilizer under normal pressure.
After holding for 10 minutes at
The polycondensation reaction was carried out at an internal temperature of 285°C. The obtained polyethylene terephthalate is [η) 0.640
, softening point 2631°C, cojL7G, 3. cojb8.
It was 4.

This polymer was melt-spun at a spinning temperature of 290° C., a cooling air flow rate of 15 m/min (26° C., relative humidity 70%), and a take-up speed shown in Table 1 to wind up filaments of 115 da/36 fil. The worn filament is
As shown in Table 1, the crystallinity and BWS had a high degree of orientation and a low degree of crystallinity.

For comparison, the same procedure as in Example 8 above was carried out except that sodium acetate and acetic anhydride were not used.

The desired filament had low orientation and high crystallinity, as shown in Table 1 for Δn and BWS.

Example 2 Anhydride-1 was used instead of acetic anhydride used in Example 1.
- The same procedure as in Example 1 was carried out except that 012 parts of phosphoric acid was used, [η) 0.641, softening point 263. ! ”(／l
Polyethylene 7 phthalate with cod L 69.8 r cal b 80 was obtained. This polymer was melt spun in the same manner as in Example 1. The obtained filament had a plane orientation of 19 and its BWS as shown in Table 1.
The crystallinity was low.

Example 3 970 parts of dimethyl terephthalate, ethylene glycol]-
and 640 parts of manganese acetate as a transesterification catalyst.
31 parts of the mixture was charged into a reactor equipped with a stirrer, a rectifier, and a filter, heated from 140°C to 230°C, and a transesterification reaction was carried out while the methanol produced was distilled out of the system. When the internal temperature reached 230'C, 018 parts of trimethyl phosphate was added as a stabilizer, and after 10 minutes, 04 parts of antimony trioxide was added as a polycondensation catalyst, followed by 0.09 parts of sodium edilate and succinic anhydride. ，
After adding 3 parts of titanium dioxide and 2.91 parts of titanium dioxide as a dissipating agent, the mixture was transferred to a polymerization kettle equipped with a stirrer and a glycol distillation filter, and a polycondensation reaction was carried out. The obtained polymer had a [η) of 0.639, a softening point of 2633°C, and a colL6
7.6. eo/b was 7.8.

This polymer was melt spun as in Example 1.

The obtained filament had a high degree of orientation and a low degree of crystallinity, as shown in Table 1 for its In and BWS.

Example 4 Example! 017 parts of butrium benzoate and anhydrous vinegar #0 in place of the sodium acetate and acetic anhydride used in
．． [ηl
0.641, Softening point 263.2"C, Cot L 7
1.3. A polymer with eol b 7.2 was obtained. This polymer was melt spun in the same manner as in Example 1. The obtained filament had a high degree of orientation and a low degree of crystallinity, as shown in Table 1 for Δn and BWS.

Claims (1)

[Claims] When producing a polyester by reacting a difunctional carboxylic acid, mainly terephthalic acid, or its dimethyl ester with at least one type of glycol, and then polycondensing the reaction product, the steps until the mosquito production reaction is completed are as follows: At any stage, a small amount selected from (al Jinpeng furfurate and carboxylic acid metal salt) is added to (al) a metal weave compound and (b
) A method for producing polyester, which comprises adding at least one type of carboxylic acid anhydride having a methylene group at the α-position.