JPH06200058A - Method for treating polyester - Google Patents

Abstract

(57) [Summary] [Purpose] As a polyester that has undergone solid-state polymerization, it has excellent hue.
To get what you got. [Constitution] Polyethylene terephthalate polyester
It is a polymer and has a particle size of 365 nm on which the solid-state polymerization has been performed.
Energy of wavelength is at least 0.1mW / cm ²And
Ultraviolet rays (using a light source such as a mercury lamp or a xenon lamp)
That is irradiated for 15 minutes to 3 hours
Steal processing method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a polyester solid-state polymerized powder or granular material, and more particularly to a method for treating a polyester solid-state polymerized powder or granular material capable of obtaining a polyester having an excellent hue. .

[0002]

2. Description of the Related Art Polyethylene terephthalate has been known to have fibers, due to its excellent mechanical and chemical properties.
It is widely used for films, industrial resins, etc., but recently it is also used for bottles, cups, trays, etc. In particular, polyester bottles have come to be widely used as containers for foods, cosmetics, etc. due to their light weight and ease of handling.

In particular, the demand for bottles has been increasing in recent years, and hue is one of the qualities required of polyesters for forming bottles. Polyester becomes yellowish due to partial thermal decomposition during melt polymerization and melt molding, but when molding a bottle from a material with a strong yellowishness, the bottle itself becomes yellowish, especially in applications where mineral water or colorless liquid is filled. Is not preferable in appearance. The coloration of the polyester becomes particularly remarkable when the polyester is produced by the transesterification method (EI method) in which the transesterification catalyst (EI catalyst) is essential.

It is considered that this is because the residue of the EI catalyst acts as a decomposition catalyst in a high temperature range such as melt polymerization and melt molding, and accelerates coloring of the polyester.

As a method for preventing the polyester from coloring, a method of using a magnesium compound as an EI catalyst or suppressing the intrinsic viscosity in melt polymerization to a low level, and subsequently increasing the amount of increase in the intrinsic viscosity in solid phase polymerization at a low reaction temperature is large. Methods such as doing are generally taken. However, due to the sophistication of required hues represented by mineral water applications in recent years, the level of coloration prevention is becoming insufficient even with these methods, and it is desired to develop a polyester material capable of forming a bottle with a more excellent hue. It is rare.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a method for treating a polyester solid-state polymerized powder or granule which can obtain a polyester having an excellent hue.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, a polyester solid-phase polymer powder having a main acid component of terephthalic acid and a main glycol component of ethylene glycol is irradiated with light having energy of 0.1 mW / cm ² or more at a wavelength of 365 nm. Irradiation is performed for 1 minute or more and 3 hours or less.

The term "mainly" as used herein means an amount exceeding 85 mol%. Therefore, ester units other than terephthalic acid and ethylene glycol can be contained within a range of less than 15 mol%, and such copolymerization components include terephthalic acid, dicarboxylic acids other than ethylene glycol, and diols or oxyacids. Specifically, aromatic dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid,
Diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, sodium-sulfoisophthalic acid,
Dibromoterephthalic acid, etc .; Alicyclic dicarboxylic acids, such as decalin dicarboxylic acid, hexahydroterephthalic acid, etc .; Aliphatic dicarboxylic acids, such as malonic acid, succinic acid,
Adipic acid and the like are exemplified. Further, as the glycol component, an aliphatic diol such as diethylene glycol,
Trimethylene glycol, tetramethylene glycol,
Hexamethylene glycol and other aromatic diols such as hydroquinone, catechol, naphthalene diol, resorcin, 4,4′-dihydroxydiphenyl sulfone, bisphenol A [2,2′-bis (4-hydroxyphenyl) propane], tetrabromobisphenol A Alicyclic diols such as cyclohexanediol; aliphatic oxycarboxylic acids such as glycolic acid, hydroacrylic acid, 3-oxypropionic acid and the like, alicyclic oxycarboxylic acids such as asiatic acid, Quinobic acid and the like; aromatic oxycarboxylic acids such as salicylic acid, m-oxybenzoic acid, p-oxybenzoic acid, mandelic acid and atrolactic acid can be mentioned.

Further, within the range where the polyester is substantially linear, a polyfunctional compound having a valence of 3 or more, such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, gallic acid An acid or the like may be copolymerized, and if necessary, a monofunctional compound such as o-benzoylbenzoic acid or naphthoic acid may be added.

Such polyesters can be manufactured by the methods accumulated in the manufacture of polyethylene terephthalate. For example, an esterification reaction is carried out using terephthalic acid and ethylene glycol, or a transesterification reaction is carried out using a lower alkyl ester of terephthalic acid (eg dimethyl ester) and ethylene glycol, and the resulting reaction product is further polycondensed. It can be manufactured. Regarding the adjustment of the amount of diethylene glycol, ethylene glycol may be added at any time of the reaction, or may be adjusted by the reaction time at normal pressure at high temperature. Further, it is preferable to use a transesterification catalyst, a polymerization catalyst, a stabilizer and the like when producing these polyesters. As these catalysts and stabilizers, those known as catalysts and stabilizers of polyester, particularly polyethylene terephthalate, can be used. Further, if necessary, other additives such as colorants, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants and the like may be used.

The polyester thus obtained is pelletized on the chips and then further solid phase polymerized in the solid phase polymerization step.

This polyester solid-state polymerized powder has 36
Irradiation with light having energy of a wavelength of 5 nm is 0.1 mW / cm ² or more. This energy is 0.1 mW / cm ²
If it is less than the above range, the effect of improving the hue is not sufficient and the processing time is long, which is not preferable. This irradiation time needs to be 15 minutes or more and 3 hours or less. If it is less than 15 minutes, the effect of improving the hue is not sufficient, and if it exceeds 3 hours, the hue tends to deteriorate, which is not preferable.

The reason why the hue is improved by irradiating the polyester with light as described above is considered to be that the vinyl terminal generated by thermal decomposition that causes coloration is cleaved by light irradiation and becomes colorless.

[0014]

EFFECT OF THE INVENTION The method of treating a polyester of the present invention is very effective as a method of treating a polyester solid-state polymerized powder, since a polyester having an excellent hue can be obtained.

[0015]

EXAMPLES The present invention will be supplemented by the following examples. In addition,
In the examples, “part” means part by weight. Moreover, the measuring method of the characteristic used in the Example is shown below.

Intrinsic viscosity ([η]) Phenol / Tetrachloroethane (60/40 weight ratio)
It measures at 35 degreeC using a mixed solvent. It was calculated from the solution viscosity.

Hue (color b value, Col b) The hue b value is measured by CM-1500 type color machine manufactured by Color Machine.

Irradiation energy Measured using a microradiometer.

[0019]

Example 1 2200 parts of dimethyl terephthalate, 1400 parts of ethylene glycol, 2 parts of an ethylene glycol solution of titanium acetate (1% as Ti) and 33 parts of diethylene glycol were charged into a transesterification reaction tank and 170 to 23.
The transesterification reaction was carried out at 5 ° C. After distilling the theoretical amount of methanol, 50 parts of a 0.76 wt% aqueous solution of germanium dioxide and 1 part of trimethyl phosphate were added, and the mixture was transferred to a polymerization reaction tank. The reaction was carried out at 270 to 280 ° C for about 15 minutes under normal pressure, and then at 280 ° C under high vacuum (high vacuum of several mmHg or more) for about 3 hours. After that, the reaction product (polymer) is put into a large amount of running water from the polymerization reaction tank by a conventional method.
Was extracted to obtain a strand type chip. [Η] of this chip was 0.65. This chip was pre-dried at 180 ° C for about 4 hours and then 215 under high vacuum of 0.5 mmHg.
Solid phase polymerization was carried out at ℃ for 6 hours and finally [η] 0.76,
A Col b 5.1 chip was obtained.

This chip was installed with a 200 W xenon lamp light source so that the average irradiation distance was 2.5 inches (36
It was supplied onto a vibrating sieve having an energy of 5 nm wavelength of 0.7 mW / cm ² ) and was irradiated with light for 15 minutes. Co of this chip
Ib was 2.9.

[0021]

Examples 2-3, Comparative Examples 1-2 The same method as in Example 1 was performed except that the irradiation time was changed.

[0022]

Example 4 The same method as in Example 1 was carried out except that the light source was sunlight on July 17 (clear weather) and the irradiation time was 60 minutes.

[0023]

[Comparative Example 3] The light source is the sunlight on December 27 (clear weather),
The same method as in Example 1 was performed except that the irradiation time was 60 minutes.

The results are listed in Table 1.

[0025]

[Table 1]

Claims (1)

[Claims] 1. A solid-state polymerized powder of polyester whose main acid component is terephthalic acid and whose main glycol component is ethylene glycol is irradiated with ultraviolet rays having an energy of a wavelength of 365 nm of 0.1 mW / cm ² or more for 15 minutes. To a method of treating polyester which is irradiated for about 3 hours.