JP3179149B2 - Polyester production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing a polyester which has sufficient strength for practical use, has a high melting point, uses a very small amount of catalyst, and can be formed into a film or the like.

[0002]

2. Description of the Related Art Aliphatic polyesters generally have a low melting point, most of which are at 70 ° C. or lower, and even if they are in a polymer region having a number average molecular weight of 10,000 or more, a polyester containing a saturated aromatic structure, For example, polyethylene terephthalate does not exhibit practically sufficient mechanical physical properties, and thus has not been considered practical.
In fact, even when the film has a film forming property, the produced film has low tear strength and tensile strength and is not practical. Among these aliphatic polyesters,
Exceptionally, aliphatic polyesters synthesized using 1,4-butanediol as a glycol component and succinic acid as a dicarboxylic acid component have a melting point of 70 ° C. or less, compared with 110% of aliphatic polyesters. It has been found that it is possible to form films having a high melting point of 115 ° C. and exhibiting considerable strength. Conventionally, it is known to use an organic compound of titanium as an esterification catalyst. In order to produce a high molecular weight polyester having a number average molecular weight of 10,000 or more, for example, in the case of bis (β-hydroxyethyl) terephthalate, 0.05 mol% of titanium and at least 0.01 mol% or more per mol of terephthalic acid are used. Organic compounds are used. In terms of the amount of the catalyst used, as much as 0.5 to 2 parts by weight of an organic compound of titanium per 100 parts by weight of the terephthalate in terms of parts by weight is used as the catalyst for the glycol removal reaction. Organic compounds of titanium are said to be less toxic than other heavy metals such as lead, tin, antimony, cadmium, chromium, etc. From the point of view, it is desired to use as little as possible. The present invention solves the conventional problems as described above, and provides a method for producing a polyester having sufficient strength for practical use, a high melting point, and a very small amount of catalyst to be used. It is intended for.

[0003]

The present inventors have conducted extensive studies on dicarboxylic acid, which is a constituent material of polyester, and glycols.
When performing esterification and deglycolization reaction using cyclohexanedimethanol and the above-mentioned dicarboxylic acid (or acid anhydride thereof) as raw materials, if titanium oxyacetylacetonate is used as a catalyst, even if the amount of the catalyst is small, it can be practically used. The inventors have found that a polyester having sufficient strength and a high melting point can be obtained, and the present invention has been completed. That is, the present invention relates to 1,4-cyclohexanedimethanol and a compound represented by the general formula

[0004]

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(Wherein, n is an integer of 2 to 12) is subjected to an esterification reaction with a dicarboxylic acid or an acid anhydride thereof, followed by a deglycolization reaction to produce a polyester. 0.0001 as a catalyst for
A method for producing an aliphatic polyester, characterized in that a polyester having a melting point of 70 ° C. or more and a number average molecular weight of 10,000 or more is obtained by using from 0.01 to 0.01 parts by weight (based on 100 parts by weight of the produced polyester) of titanium oxyacetylacetonate. Is provided. As described above, the present invention is characterized in that it has been found that even when the organic compound of titanium is used in an amount of 0.01 part by weight or less, it is useful as a reaction catalyst for 1,4-cyclohexanedimethanol and an aliphatic dicarboxylic acid. It is useful for further improving the safety of the produced polyester to the human body, in combination with the inertness of the organic compound of titanium against living organisms.

Hereinafter, the present invention will be described in more detail.
Unless otherwise specified, the number average molecular weight is simply expressed as molecular weight.

The production of a saturated polyester using 1,4-cyclohexanedimethanol and the above dicarboxylic acid can be performed by a known technique. The conditions for the esterification reaction and the deglycolization reaction when producing this saturated polyester can be set to appropriate conditions conventionally used, and are not particularly limited.

The 1,4-cyclohexanedimethanol used in the present invention has the general formula

[0009]

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## STR1 ## There are a cis-form and a trans-form, and the trans-form is preferred for producing a polyester having a high melting point. Also, for example, Eastman Industrial Chemicals of the United States
Mixtures in which the cis and trans forms of cyclohexanedimethanol are in a ratio of 1: 2 are commercially available, but can also be used in the present invention.

The amount of the glycol component used in the present invention is equimolar to the dicarboxylic acid component, but is generally used in a slightly excessive amount due to distillation during esterification.

The dicarboxylic acid used in combination with 1,4-cyclohexanedimethanol has the general formula

[0013]

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Wherein n is an integer of 2 to 12 or an acid anhydride thereof, for example, succinic acid,
Adipic acid, suberic acid, sebacic acid, dodecanoic acid and the like can be mentioned, among which succinic acid, and further, a mixed acid of succinic acid and other dicarboxylic acids, for example, adipic acid, suberic acid, sebacic acid, dodecanoic acid. It is suitable.
When a mixed acid is used, for example, a suitable mixing ratio of each component of a two-component system or more composed of succinic acid and another dicarboxylic acid is usually 50 mol% or more of succinic acid, preferably 60 mol% or more, The content of dicarboxylic acids other than succinic acid is 50 mol% or less, preferably 40 mol% or less.

[0015] The catalyst used in the present invention is titanium oxyacetylacetonate. Titanium oxyacetylacetonate has the general formula

[0016]

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## EQU1 ## The catalyst is used in an amount of 0.0001 to 0.01 parts by weight, preferably 0.001 to 0.01 parts by weight, based on 100 parts by weight of a saturated polyester obtained by reacting 1,4-cyclohexanedimethanol with dicarboxylic acid. Parts by weight are good. If the amount is less than 0.0001 part by weight, the action of the catalyst becomes weak, and it becomes difficult to obtain a target molecular weight. Further, even if the amount is more than 0.01 part by weight, the effect is not largely changed, and only the catalyst residue increases, which is not preferable. The deglycolization catalyst may be added from the beginning of the esterification reaction between glycol and dicarboxylic acid, or may be added after the esterification reaction is completed. The polyester produced as described above has practically sufficient strength and flexibility, and has a high melting point, so that various molding methods can be used according to various uses. For example, when a film is formed using this, a known film forming method can be used, and there is no particular limitation. Further, at the time of molding, various molding auxiliaries, for example, fillers (inorganic and organic), coloring agents, reinforcing materials, waxes, thermoplastic polymers, oligomers, and the like can be used in combination depending on the use.

[0018]

The present invention will be described below by way of examples.

EXAMPLE 1 300 g of 1,4-cyclohexanedimethanol, 292 g of adipic acid, 0.028 g of titanium oxyacetylacetonate were placed in a 1-liter separable flask equipped with a stirrer, a distillation condenser, a thermometer and a gas inlet tube. And esterified at 205 to 210 ° C. in a nitrogen stream to adjust the acid value to 5.1. Finally, the pressure was reduced to 0.6 Torr,
Deglycolation was performed at 15 ° C. for 10 hours to obtain a polyester (C) having a molecular weight of 16,900. When cooled to room temperature,
It became a slightly yellowish white wax. The melting point was about 105 ° C. Separately, when the reaction was conducted under the same conditions without using titanium oxyacetylacetonate, the molecular weight of the obtained polyester (D) was 6,900.
The difference was large.

[0020]

[0021]

According to the present invention, there is provided a process for producing a polyester which can be molded into a film or the like, which has sufficient strength for practical use, has a high melting point, and can use a very small amount of a catalyst. You.

Claims (1)

(57) [Claims] 1. A 1,4-cyclohexanedimethanol,
General formula (Wherein n is an integer of 2 to 12) is subjected to an esterification reaction with a dicarboxylic acid or an acid anhydride thereof, followed by a deglycolization reaction to produce a polyester. represented by the following formula 0.0001-0.01 parts by weight (based on the generated polyester 100 parts by weight)
By using the titanium oxy acetylacetonate is characterized by obtaining a melting point 70 ° C. or more and a number average molecular weight of 10,000 or more polyesters, process for producing a polyester. Embedded image