KR940003882B1 - Forming method of polyester - Google Patents

Abstract

The method manufactures the modified polyester dyable with alkaline dye. This modified polyester comprises terephthalic acid, ethylene glycol and 5-metal sulfo-isophthalate. The manufacturing method comprises: A) adding 5-sodium sulfoisophthalate dimethyl in the esterification of terephthalic acid and ethylene glycol at the time of above 85% of reaction rate; and B) proceeding the esterification at 225-235 deg.C in the presence of organic tin compound of formula of (I). In formula, R' is C1-C8 of alkyl or allyl and R" is hydroxyl, C1-C8 alkyl or allyl group.

Description

Method of Making Modified Polyester

The present invention relates to a method for producing a modified polyester that can be dyed with the basic dye of the present invention, and more particularly, a direct esterification method using terephthalic acid (hereinafter abbreviated as TPA) and ethylene glycol (hereinafter abbreviated as EG) as main starting materials. The present invention relates to a method for producing a modified polyester having good heat resistance, wherein 0.5 to 5 mol% of the acid component is a 5-metal sulfoisophthalic acid component (hereinafter, abbreviated as MSI).

In general, polyethylene terephthalate (hereinafter abbreviated as PET) has excellent physical and chemical properties and is widely produced and used in medical and industrial fibers in large quantities. However, since PET fibers have no affinity for ionic dyes, it is necessary to use disperse dyes for dyeing, and to dye at high temperatures, and the color of the dyeings is not clear.

As a method for solving such a problem, a method of making a modified polyester capable of copolymerizing an MSI component and dyeing with a basic dye (JP-A-34-10497) has been put into practical use, and industrially such modified polyester is commercially available. Many researches have been conducted on the preparation method, and various proposals have been made. For example, the reaction between TPA and EG in the reaction of 5-sosulsulfoisophthalate (hereinafter abbreviated as DMSSI) and EG is performed. The reaction product is added at a transesterification rate of 75 to 95% and polycondensed (JP-A 58-45452). The DMSSI is added to the esterification product of TPA and EG having an esterification rate of 80 to 98.5%. The method of polycondensation (JP-A-59-1735) etc. is proposed.

However, when the copolyester is prepared by adding the sulfonate compound, the by-product amount of diethylene glycol (hereinafter abbreviated as DEG) component is increased because the time for heating the sulfonate compound together with EG is increased. There is a problem that the melting point and the heat resistance of the deterioration, this phenomenon becomes more remarkable especially when the direct esterification method is used.

Accordingly, the present inventors have solved this problem, and as a result of repeating the research on a method for industrially advantageously producing a modified polyester which is low in by-product amount of the DEG component, has good heat resistance, and is soluble in base dyes, the by-product of DEG It is found that the reaction temperature is related to the present invention, and the present invention has been reached as follows.

That is, in the present invention, when TPA and EG are the main starting materials, 0.5 to 5 mol% of the computerized component is used to prepare a modified polyester of MSI component, and the DMSSI is converted to TPA and EG when the esterification rate is at least 85% or more. It is added to the esterification reaction with, and the esterification reaction is performed at the reaction temperature of 225-235 degreeC in presence of at least 1 sort (s) of the organic tin compound represented with the following general formula, The manufacturing method of modified polyester characterized by the above-mentioned. will be.

In formula, R 'represents a C1-C8 alkyl group, an allyl group, and R "represents a hydroxyl group, a C1-C8 alkyl group, or an allyl group, and R" and R "may be same or different.

In the present invention, when the DMSSI is added at the time when the esterification reaction rate is 85% or less, the selection of the addition time is important because the byproduct amount of DEG increases and the present invention cannot achieve the object. In addition, as the organotin compound used in the present invention, R 'is n-butyl group, and R "is n-butyl or hydroxyl group, and the usage amount may be 0.01-0.04 mol% with respect to the computing component which comprises polyester. If the amount is less than this, the esterification time will be longer, so that the effect of reducing the DEG by-product for the purpose of the present invention is not obtained, and in more cases, the yellowness of the obtained polyester is increased. It is not preferable because a problem occurs.

As described above, the present invention can be dyed with a basic dye, and it is possible to industrially advantageously produce a modified polyester having excellent heat resistance.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

However, the present invention is not limited by the examples, and the physical properties of the polyesters in the examples were measured by the following method, and parts represent parts by weight.

* Intrinsic viscosity: The polyester was dissolved in a phenol / tetrachloroethane (3/2 weight ratio) mixed solvent and measured at 25 ° C.

* Carboxyl group concentration: Measured by the method of Phol described in Analytical Chem., Vol. 26, page 1616 (1954).

Diethylene glycol content: The polyester was hydrolyzed with sodium hydroxide, and then quantified by gas chromatography.

Color: The polyester chip was measured using a colorimeter at room temperature to show L-order and yellowness.

Example 1

166 parts of TPA, 74 parts of EG, and 0.07 parts of dibutyltin oxide were placed in an autoclave equipped with a reflux tower, and reacted at 230 ° C. for 3.0 hours to obtain an esterification rate of 88%. The reaction was continued for an additional 30 minutes under conditions to transfer the polyester oligomer (97% esterification reaction rate) to an autoclave for polymerization, and the temperature was gradually raised and reduced in pressure to reach 285 ° C and 0.8 mmHg after 40 minutes. After 60 minutes of reaction under these conditions, the system was pressurized with nitrogen, discharged and granulated in water, and the physical properties of the obtained polyester are shown in the following table.

Example 2

In Example 1, except that 0.06 parts of butyl tin hydroxide instead of dibutyl tin oxide was used in the same manner as in Example 1, and the physical properties of the obtained polyester are shown in the following table.

Comparative Example 1

In Example 1, 0.75 parts of antimony trioxide was added without using dibutyltin oxide, and the esterification temperature was the same except that the reaction temperature was 255 ° C. The physical properties of the obtained polyester are shown in the following table.

Comparative Example 2

Except for using dichlorotin oxide in Example 1 0.075 parts of antimony trioxide was the same as in Example 1, the polyester properties obtained are shown in the following table.

Example 3

In Example 1, all but the addition amount of dibutyl tin oxide was the same as 0.03 parts and the physical properties of the obtained polyester is shown in the following table.

Example 4

In Example 1, the amount of dibutyltin oxide was 0.095 parts except that the same amount was used, and the physical properties of the obtained polyester were as shown in the following table.

Comparative Example 3

In Example 1, the amount of dibutyltin oxide was used in the same manner except for 0.11 parts, and the physical properties of the obtained polyester are shown in the following table.

[Comparative Example 4]

In Example 1, except that the amount of dibutyltin oxide was 0.2 parts, all were the same to obtain a polyester, and the physical properties thereof are shown in the following table.

[Comparative Example 5]

Except having made the esterification temperature 245 degreeC, it was the same as Example 1, The physical properties of the obtained polyester are as follows.

Comparative Example 6

Except that the esterification temperature was 215 ℃ and all the same as in Example 1, the physical properties of the resulting polyester is shown in the table below.

TABLE 1

As described above, according to the present invention, it is possible to maintain a polyester having a small amount of DEG by-products and good color at an industrial reaction rate and to produce it.

Claims (2)

In a method for producing a modified polyester in which 0.5 to 5 mol% of the total acid component is a 5-metal sulfoisophthalic acid component using terephthalic acid and ethylene glycol as the main starting materials, when the esterification reaction rate is at least 85% or higher, 5 Dimethyl sodium sulfoisophthalate is added to an esterification reaction product of terephthalic acid and ethylene glycol, and the esterification reaction is carried out at a reaction temperature of 225 to 235 ° C in the presence of at least one organic tin compound represented by the following general formula: Method for producing a modified polyester, characterized in that. Wherein R 'represents an alkyl group or allyl group having 1 to 8 carbon atoms, and R "represents a hydroxyl group or an alkyl group or allyl group having 1 to 8 carbon atoms, and R' and R" may be the same or different. A process for producing a modified polyester according to claim 1, wherein R 'is a butyl group and R "is a butyl group or a hydroxyl group as the organic tin compound.