JPS60219226A - Production of high-polymerization degree polyester - Google Patents

Abstract

PURPOSE:To obtain a high-polymerization degree polyester excellent in mechanical and thermal properties within a short time, by effecting the polycondensation reaction for producing a polyester by adding a predetermined amount of hydrogen chloride after completion of the esterification or transesterification. CONSTITUTION:A polyester is produced by reacting terephthalic acid or a terephthalic acid-based dicarboxylic acid (or its esterifiable derivative) with ethylene glycol or an ethylene glycol-based glycol (its esterifiable derivative). Hydrogen chloride, as a polycondensation catalyst, in an amount of 0.2X10<-4>- 30X10<-4>mol, per mol of the acid component is added to the reaction system after the esterification or transesterification reaction is completed, and the reaction mixture is polycondensed to obtain the purpose high-polymerization degree polyester. The obtained polyester is separated from hydrogen chloride by drying to obtain a pure polyester.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing polyester, particularly mechanically.

The present invention relates to a method for producing a high degree of polymerization polyester with excellent thermal properties in a short time.

(Prior Art) Polyesters, particularly polyethylene terephthalate or polyesters having ethylene terephthalate units as their main constituent units, have been widely used in fibers, films, and other molded products because of their excellent properties.

To produce polyethylene terephthalate.

Usually, bis-(β-hydroxyethyl) terephthalate and/or its low polymer is formed by transesterifying dimethyl terephthalate and ethylene glycol or by directly esterifying terephthalic acid and ethylene glycol. It is produced by a method of producing polyester with desired properties through a polycondensation reaction.

However, in one polycondensation step, especially in the final polycondensation step, the temperature is usually kept at 280°C to 300°C for a long time.
Because a high temperature of ℃ is required, for example, the intrinsic viscosity is 0.
In order to obtain a polyester of 6 or more, thermal decomposition reactions and other side reactions are almost always involved, which usually results in yellow coloring, increased carboxyl end group concentration, and increased content of diethylene glycol bonds. The physical properties of the polyester will be impaired.

Catalysts are generally used in the production of polyester. For example, Japanese Patent Publication No. 2B-4640 states that hydrogen chloride is used as an esterification reaction catalyst, but if hydrogen chloride is added from the time of the esterification reaction, As a result of side effects, the content of diethylene glycol bonds increases and the activity as a single polycondensation reaction catalyst is extremely reduced, making it impossible to shorten the double condensation reaction time.

(Objective of the Invention) An object of the present invention is to provide a method for producing a highly polymerized polyester having excellent mechanical and thermal properties in a short time.

(Structure of the Invention) As a result of intensive research to achieve the above object, the present inventors have discovered that it is effective to add hydrogen chloride in a predetermined amount at a predetermined time and have arrived at the present invention. The gist is as follows.

When producing polyester by reacting terephthalic acid, a difunctional carboxylic acid containing terephthalic acid as the main component, or its ester-forming derivative with ethylene glycol, a glycol containing terephthalic acid as the main component, or its ester-forming derivative, esterification is required. A method for producing polyester, which comprises adding hydrogen chloride at a ratio of 0.2XIO-' to 30X10-' mol per 1 mol of the raw acid component after the reaction or transesterification reaction is substantially completed.

In the present invention, hydrogen chloride must be added at the time when the esterification reaction or transesterification reaction is substantially completed, that is, when the 1 reaction rate is 90% or more, especially 92 to 98%. If it is added earlier, the above-mentioned problems will occur.

The amount of hydrogen chloride added needs to be in the ratio of 0.2 x 10-' to 30 x 10-' mol per 1 mol of the raw acid component of the polyester. If the amount added is less than this range, the addition effect will not be substantially recognized, and if the amount added is more than this range, the addition effect will not only be saturated, but also cause a delay in the polycondensation reaction. In the reactor, the reactor corrodes, making it necessary to use a special reactor such as one made of ceramic.

In the present invention, the acid component is mainly ester-forming derivatives such as terephthalic acid or its alkyl esters and phenyl esters. Methyl isophthalic acid.

5-Sodium sulfoisophthalic acid, phthalic acid.

Diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid.

Naphthalene dicarboxylic acid, adipic acid, hetano\sinic acid,
It may be replaced with one or more types of p-[droxyethoxybenzoic acid or ester-forming derivatives thereof. On the other hand, the glycol component is mainly ethylene glycol or ester-forming derivatives of ethylene glycol such as ethylene oxide;
For example, propylene glycol, tetramethylene glycol, 1,4-cyclohexane dimetatool,
, 4-cyclohexanediol, {circle around (2)}, 4-bis-hydroxyethoxyhensen, diol compounds such as aliphatic, aromatic, and alicyclic diol compounds, or ester-forming derivatives thereof.

Any known method can be applied to produce polyester from these difunctional carboxylic acids and glycols. For example, dimethyl terephthalate and ethylene glycol are transesterified, terephthalic acid and ethylene glycol are directly esterified, or terephthalic acid and ethylene oxide are subjected to an addition reaction to form bis=(β-hydroxyethyl). Terephthalate and/or a low polymer thereof is formed, and then a predetermined amount of hydrogen chloride is added to carry out a polycondensation reaction to obtain predetermined properties. In addition to the hydrogen chloride catalyst, other additives may be added, such as other catalysts, as required, for example, once the transesterification or esterification step has been substantially completed.

Stabilizer, pigment, dye, fluorescent whitening agent, nucleating agent 1 polymerization accelerator,
It is also possible to add lubricants, fillers, etc.

The degree of polymerization of the polyester produced is not particularly limited, but phenol-tetrachloroethane (1:1 ratio) is practically preferred.
The intrinsic viscosity (hereinafter referred to as [η]) determined from the solution viscosity measured at 20° C. when dissolved in a mixed solvent of is in the range of 0.6 to 1.0.

In the present invention, polyester is produced without adding any additives other than a hydrogen chloride catalyst, and the polyester is produced at a normal drying temperature (14
Relatively high temperature conditions (around 0℃).

Zunawara 1 Usually 160-220℃, preferably 180℃
By drying with hot air or under reduced pressure at ~200"C for a long time to sufficiently disperse the hydrogen chloride remaining in the polyester, it is also possible to obtain pure polyester with no residues such as catalysts other than polyester. This makes it possible to extremely reduce the rate of thermal decomposition and the decrease in degree of polymerization during remelting.

(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

In the examples, "parts" indicate parts by weight, and characteristic values were measured as follows.

(a+Carboxyl terminal group concentration (COO11) is determined by titration with 1/10 normal potassium hydroxide solution in Hensyl alcohol, and the lower the concentration, the better.

(The concentration (DEC) of diethylene glycol bonds is determined by decomposing under refluxing methanol for 2 hours and analyzing and quantifying it by gas chromatography. 1 Generally, the lower the concentration, the better.

Examples and Comparative Examples Bis(β-hydroxyethyl) terephthalate and its low polymer were produced from terephthalic acid and ethylene glycol by a known method. To this 100 parts, hydrogen chloride was added in the amount shown in Table 1 (HCI (mol) is the amount per 1 mol of the acid component), and after raising the temperature to 285°C, the pressure in the system was gradually reduced, and finally A polycondensation reaction was carried out using 11 g of Q, 1 mm, for the time shown in Table 1.

In addition, as a reference example, a polyester was produced in the same manner using antimony trioxide (2×10 −' mol/mol of acid component) instead of hydrogen chloride as a catalyst.

Table 1 shows the characteristic values of the obtained polyester.

Table 1: 1 ton) : 1 -1 1 1 □□□□□□□□□-1" 1 1" I □1) 1 In addition, residual hydrogen chloride in the dry polyester obtained in Example 1 The amount is the detection limit (30 ppm) by fluorescent X-ray method.
It was less than

Furthermore, in Comparative Example 3 in which a large amount of hydrogen chloride was added, the degree of polymerization did not increase, and the stainless steel reactor was severely corroded.

(Effects of the Invention) As described above, according to the method of the present invention, a polyester with a high degree of polymerization and excellent mechanical and thermal properties can be produced in a short time. This prevents the increase in carboxyl end groups and diethylene glycol bonded gold content in the polyester that occurs during the post-reaction treatment process, resulting in a fiber.

The commercial value when used as a film or other molded product can be greatly improved.

Furthermore, if polyester is produced without adding any additives other than hydrogen chloride, it is possible to obtain pure polyester containing no residues such as catalysts.

Patent applicant Nihon Ester Co., Ltd. Agent Yuzo Kodama

Claims (1)

[Claims] (1) When producing polyester by reacting terephthalic acid, a difunctional carboxylic acid containing terephthalic acid as the main component, or its ester-forming derivative with ethylene glycol, a glycol containing terephthalic acid as the main component, or its ester-forming derivative. , a polyester characterized in that after the esterification reaction or the transesterification reaction is substantially completed, hydrogen chloride is added at a ratio of 0.2xlO-' to 30 x 10 to 4 mol per mol of the raw acid component. manufacturing method.