JP2011174012A - Method for producing copolyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a copolyester inexpensively in good productivity by re-using a cyclic oligomer which is a byproduct of a polycondensation reaction and copolymerizing an aliphatic compound. <P>SOLUTION: This method for producing the polyester comprising (A) a dicarboxylic acid consisting mainly of an aromatic dicarboxylic acid and a 6-12C aliphatic dicarboxylic acid, and (G) a glycol consisting mainly of the glycol selected from the group consisting of ethylene glycol, neopentyl glycol, propylene glycol, 1,6-hexane diol and cyclohexane dimethanol is provided by comprising an esterification reaction process, a ring-opening reaction process of performing the ring-opening reaction by mixing 100 pts.mass low polymer obtained by the esterification reaction process and 5 to 40 pts.mass cyclic oligomer constituted by the same monomer with the monomer constituting the above low polymer and the polycondensation reaction process. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a copolyester that can be suitably used for various materials such as fibers, films, and molded articles in a short time with high production efficiency and at low cost.

Copolyesters mainly composed of aromatic dicarboxylic acids and aliphatic dicarboxylic acids and aliphatic diols are used in various materials such as fibers, films and molded articles.
However, when producing a copolyester having the above composition, there is a problem that a large amount of a cyclic oligomer composed of an aromatic dicarboxylic acid and an aliphatic diol or an aliphatic dicarboxylic acid and an aliphatic diol may be by-produced during the polycondensation reaction. It was.

  Patent Document 1 discloses that by-products of cyclic oligomers are suppressed by changing the charging ratio of dicarboxylic acid and glycol. However, there has been no technique for reusing the recovered by-product cyclic oligomer.

JP 2009-35596 A

  In view of the prior art, the present invention intends to provide a method that can use a cyclic oligomer, which is a byproduct of a polycondensation reaction, as a raw material, and can be produced in a short time with high production efficiency and at low cost.

As a result of investigations to solve the above problems, the present inventors have reached the present invention. That is, the gist of the present invention is as follows.
The group which consists of dicarboxylic acid (A) which has aromatic dicarboxylic acid and C6-C12 aliphatic dicarboxylic acid as a main component, and ethylene glycol, neopentyl glycol, propylene glycol, 1,6-hexanediol, and cyclohexanedimethanol A method for producing a polyester comprising a glycol (G) comprising as a main component a glycol selected from the following, which comprises the following steps.
Esterification reaction step: a step of esterifying the dicarboxylic acid (A) and the glycol (G) to obtain a low polymer thereof,
Ring-opening reaction step: 100 parts by mass of the low polymer obtained in the esterification reaction step and 5 to 40 parts by mass of a cyclic oligomer composed of the same monomer as that constituting the low polymer are mixed to carry out the ring-opening reaction. Process to perform and polycondensation reaction process: Process to perform polycondensation reaction of product after ring-opening reaction

According to the production method of the present invention, when a polyester having a specific copolymer composition is polymerized, a cyclic oligomer, which is a by-product of a polycondensation reaction, is used as a raw material to produce a target polyester in a short time. It can be manufactured efficiently and inexpensively.
Moreover, the copolyester obtained by the production method of the present invention can be suitably used in various materials such as fibers, films and molded articles.

Hereinafter, the present invention will be described in detail.
The copolymerized polyester produced by the production method of the present invention comprises an aromatic dicarboxylic acid and a dicarboxylic acid (A) mainly composed of an aliphatic dicarboxylic acid having 6 to 12 carbon atoms, ethylene glycol, neopentyl glycol, propylene glycol. , 1,6-hexanediol, cyclohexanedimethanol is a copolyester composed of glycol (G) whose main component is glycol selected from the group consisting of cyclohexanedimethanol.

As dicarboxylic acid (A), it is necessary to use together aromatic dicarboxylic acid and C6-C12 aliphatic dicarboxylic acid.
Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 5-sodium sulfoisophthalic acid, and naphthalenedicarboxylic acid. These may be derivatives or anhydrides. Among these, terephthalic acid and isophthalic acid are preferable from the viewpoint of resin characteristics and cost performance.

  Examples of the aliphatic dicarboxylic acid having 6 to 12 carbon atoms include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. Among these, adipic acid, azelaic acid, and sebacic acid are preferable from the viewpoint of cost performance.

  Further, in the method for producing the copolyester of the present invention, in addition to the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid having 6 to 12 carbon atoms, the succinic acid can be used within a range not exceeding 20 mol% with respect to the total carboxylic acid. Saturated aliphatic dicarboxylic acids such as acid, glutaric acid and hydrogenated dimer acid, unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, dimer acid, dodecenyl succinic acid and terpene-maleic acid adduct, 1,4-cyclohexanedicarboxylic acid An alicyclic dicarboxylic acid such as an acid, 1,2-cyclohexanedicarboxylic acid, or 1,3-cyclohexenedicarboxylic acid may be used in combination. These may be derivatives or anhydrides.

  The content ratio of the aromatic dicarboxylic acid to the total dicarboxylic acid is preferably 50 to 80 mol%. Moreover, it is preferable that it is 20-50 mol% as a content rate of C6-C12 aliphatic dicarboxylic acid with respect to all the dicarboxylic acids.

  The glycol (G) is selected from the group consisting of ethylene glycol, neopentyl glycol, propylene glycol, 1,6-hexanediol, and cyclohexanedimethanol. The glycol (G) contains at least one kind of the above-mentioned glycol, and may contain plural kinds.

  The total content of glycol selected from the group consisting of ethylene glycol, neopentyl glycol, propylene glycol, 1,6-hexanediol, and cyclohexanedimethanol with respect to all glycols is preferably 50 to 100 mol%, 80 to More preferably, it is 100 mol%.

  Further, in addition to the above-mentioned glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol and the like are within a range not exceeding 50 mol% with respect to the total glycol. Trivalent or higher polyols such as diol, trimethylolpropane and pentaerythritol can also be used.

Next, a manufacturing method will be described.
The production method of the present invention comprises the following three steps.
Esterification reaction step: a step of esterifying the dicarboxylic acid (A) and the glycol (G) to obtain a low polymer thereof,
Ring-opening reaction step: a step of mixing the low polymer obtained in the esterification reaction step and a cyclic oligomer to perform a ring-opening reaction,
Polycondensation reaction step: The polycondensation reaction step of distilling off the glycol of the product after the ring-opening reaction to obtain a copolyester having a desired degree of polymerization

First, the esterification reaction step will be described.
In the esterification reaction step, the dicarboxylic acid (A) and the glycol (G) are esterified under an inert atmosphere to obtain a low polymer having a polymerization degree of 2 to 10.

  The reaction temperature is preferably from 200 to 280 ° C, more preferably from 200 to 260 ° C. The reaction time is preferably 2 to 4 hours. By making it 2 to 4 hours, a thing with a good color tone can be obtained efficiently. The esterification reaction time is a time from when the desired temperature is reached until the esterification reaction rate reaches 95% or more.

Next, the ring-opening reaction step will be described.
In the ring-opening reaction step, the low polymer obtained in the esterification reaction step is mixed with a cyclic oligomer composed of the same monomer as that constituting the low polymer, and the cyclic oligomer is opened at normal pressure. .

In the present invention, the cyclic oligomer refers to a cyclic oligomer in which one or more pairs of one monomer of dicarboxylic acid and one monomer of glycol are combined.
As the cyclic oligomer, a cyclic monomer to a cyclic trimer is preferably used. For example, isophthalic acid-ethylene glycol cyclic dimer, terephthalic acid-neopentyl glycol cyclic dimer, isophthalic acid-neopentyl glycol cyclic dimer, isophthalic acid-propylene glycol cyclic trimer, sebacic acid-neopentyl A glycol cyclic monomer may be used, and a plurality of types may be used.

  The addition amount of the cyclic oligomer is required to be 5 to 40 parts by mass with respect to 100 parts by mass of the low polymer obtained by the esterification reaction, and preferably 10 to 35 parts by mass. If the addition amount is less than 5 parts by mass, the esterification reaction time is not shortened and the production efficiency is not improved, which is not preferable. On the other hand, when the addition amount exceeds 40 parts by mass, the time for ring-opening the cyclic oligomer becomes long, and the production efficiency is not improved.

  Although the manufacturing method of the cyclic oligomer mixed by a ring-opening reaction process is not specifically limited, For example, it can extract and obtain from the distillate collect | recovered from the distillation line as a by-product in a polycondensation reaction process. Usually, since the distillate containing glycol as a main component recovered from the distillation line contains a large amount of cyclic oligomers and monomers as impurities, the distillate recovered by extracting the solvent is purified to obtain the cyclic oligomer. Can be obtained.

  The cyclic oligomer to be mixed with the low polymer needs to be composed of the same monomer as that constituting the low polymer. For this purpose, for example, a cyclic oligomer obtained by polycondensation of polyesters having the same monomer structure is recovered, and the cyclic oligomer may be used in the next polymerization.

  The ring-opening reaction temperature is preferably from 200 to 290 ° C, more preferably from 220 to 270 ° C. The reaction time is preferably 5 to 30 minutes under normal pressure in order to open the cyclic oligomer. The ring-opening reaction time is the time from when the desired temperature is reached until the endothermic reaction occurs without heating and the reaction temperature rises by 5 ° C.

  In addition, an esterification reaction process and a ring-opening reaction process can also be made into 1 process by charging and reacting a raw material monomer and a cyclic oligomer collectively.

Next, the polycondensation step will be described.
In the polycondensation step, glycol is distilled off from the product obtained in the ring-opening reaction step, and the polycondensation reaction proceeds until a polymerization degree of 30 to 200 is reached.

  The reaction temperature is preferably 200 to 290 ° C, more preferably 220 to 270 ° C. The degree of vacuum is preferably 0.9 hPa or less, and more preferably 0.75 hPa or less.

  In the esterification reaction, ring-opening reaction, and polycondensation reaction, polymerization is performed by appropriately selecting from compounds such as antimony, titanium, germanium, tin, and zinc as necessary. Also, stabilizers such as phosphoric acid, phosphorous acid, trimethyl phosphate, triethyl phosphate, color improvers such as cobalt compounds, fluorescent agents, dyes, pigments such as titanium dioxide, bromine compounds, phosphorus compounds, etc. An additive such as a flame retardant may coexist.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but is not limited thereto. In addition, the physical property value measurement of the polyester resin was performed by the following method.
1. Polyester resin composition
^It calculated | required by < ¹ > H-NMR analysis (the JEOL make, 400MHz).
2. Esterification reaction rate Calculated according to the following equation.
Esterification reaction rate = {(equivalent number of all ester bonds contained in 1 ton of sample + equivalent number of terminal carboxyl group contained in 1 ton of sample) − (equivalent number of terminal carboxyl group contained in 1 ton of sample) )} ÷ (total ester bonds contained in 1 ton of sample + equivalent number of terminal carboxyl groups contained in 1 ton of sample) × 100
[Total number of equivalents of all ester bonds and equivalents of terminal carboxyl groups]
A sample (1.0 g) was dissolved in 20 ml of 0.5N potassium hydroxide ethanol solution, heated to reflux, hydrolyzed, and titrated with 0.5N hydrochloric acid aqueous solution, and the number of equivalents contained in 1 ton of sample was calculated.
[Equivalent number of terminal carboxyl group]
A sample of 2.5 g was dissolved in 20 ml of dimethylformamide, titrated with a 0.1N sodium hydroxide methanol solution, and the number of equivalents contained in 1 ton of sample was calculated.

  In the following, the mass part of the cyclic oligomer is an amount per 100 parts by mass of the low polymer.

Example 1
As dicarboxylic acid (A), 13.3 kg of isophthalic acid and 16.2 kg of sebacic acid were used. As glycol (G), 5.0 kg of ethylene glycol and 12.5 kg of neopentyl glycol (isophthalic acid: sebacic acid: ethylene glycol: neopentyl) Glycol = 50: 50: 50: 75 (molar ratio), (G) / (A) = 1.25 (molar ratio)), these were charged into an esterification reaction vessel, pressure 0.3 MPa, temperature 240 ° C. The esterification reaction was performed for 3 hours in a nitrogen atmosphere. The obtained low polymer was 41.5 kg. After transferring the obtained low polymer to a polycondensation reaction tank, 4.4 kg (10.6 parts by mass) of isophthalic acid-ethylene glycol cyclic dimer, and 8.0 kg of isophthalic acid-neopentyl glycol cyclic dimer. (19.3 parts by mass) was added, and 33 g of tetrabutyl titanate (5.2 × 10 ⁻⁴ mol per mol of isophthalic acid and sebacic acid in total) was added, and the ring-opening reaction was performed for 0.5 hours at normal pressure. I did it. Thereafter, the pressure was reduced to 0.5 hPa, and a polycondensation reaction was performed at 260 ° C. for 4 hours to obtain a copolyester having an intrinsic viscosity of 0.80 dl / g. As a result, 48.9 kg of copolyester was obtained.

Example 2
The charging amount in Example 1 was 19.9 kg of isophthalic acid, 16.2 kg of sebacic acid, 6.2 kg of ethylene glycol, and 15.6 kg of neopentyl glycol (isophthalic acid: sebacic acid: ethylene glycol: neopentyl glycol = 60: 40: 50:75 (molar ratio), (G) / (A) = 1.25 (molar ratio)) to obtain 50.9 kg of a low polymer. Next, 2.9 kg (5.7 parts by mass) of isophthalic acid-ethylene glycol cyclic dimer and 5.3 kg (10.4 parts by mass) of isophthalic acid-neopentyl glycol cyclic dimer were used as cyclic oligomers. In the same manner as in Example 1, an esterification reaction, a ring-opening reaction, and a polycondensation reaction were performed. As a result, 53.2 kg of copolyester was obtained.

Example 3
The amount of charge in Example 1 is 13.3 kg of isophthalic acid, 16.2 kg of sebacic acid, 20.8 kg of neopentyl glycol (isophthalic acid: sebacic acid: neopentyl glycol = 50: 50: 125 (molar ratio), (G) /(A)=1.25 (molar ratio)), 44.7 kg of a low polymer was obtained. Subsequently, an esterification reaction, a ring-opening reaction, and a polycondensation reaction were performed in the same manner as in Example 1 using 15.0 kg (33.5 parts by mass) of sebacic acid-neopentylglycol cyclic monomer as a cyclic oligomer. As a result, 54.0 kg of copolyester was obtained.

Example 4
The charge in Example 1 is 24.9 kg of isophthalic acid, 16.2 kg of sebacic acid, 7.1 kg of ethylene glycol, and 18.0 kg of neopentyl glycol (isophthalic acid: sebacic acid: ethylene glycol: neopentyl glycol = 65.2: 34.8: 50: 75 (molar ratio), (G) / (A) = 1.25 (molar ratio)), and 57.0 kg of a low polymer was obtained. Next, 1.5 kg (2.6 parts by mass) of isophthalic acid-ethylene glycol cyclic dimer and 1.5 kg (2.6 parts by mass) of isophthalic acid-neopentyl glycol cyclic dimer were used as cyclic oligomers. In the same manner as in Example 1, an esterification reaction, a ring-opening reaction, and a polycondensation reaction were performed. As a result, 53.9 kg of copolyester was obtained.

Comparative Example 1
The charging amount in Example 1 is 26.6 kg of isophthalic acid, 16.2 kg of sebacic acid, 7.4 kg of ethylene glycol, and 18.7 kg of neopentyl glycol (isophthalic acid: sebacic acid: ethylene glycol: neopentyl glycol = 66.7: 33.3: 50: 75 (molar ratio), (G) / (A) = 1.25 (molar ratio)), and 60.0 kg of a low polymer was obtained. Next, an esterification reaction, a ring-opening reaction, and a polycondensation reaction were performed in the same manner as in Example 1 except that no cyclic oligomer was added. As a result, 51.8 kg of copolyester was obtained.

Comparative Example 2
The charge in Example 1 is 24.9 kg of isophthalic acid, 16.2 kg of sebacic acid, 7.1 kg of ethylene glycol, and 18.0 kg of neopentyl glycol (isophthalic acid: sebacic acid: ethylene glycol: neopentyl glycol = 65.2: 34.8: 50: 75 (molar ratio), (G) / (A) = 1.25 (molar ratio)), and 57.0 kg of a low polymer was obtained. Next, 0.8 kg (1.4 parts by mass) of isophthalic acid-ethylene glycol cyclic dimer and 1.5 kg (2.6 parts by mass) of isophthalic acid-neopentyl glycol cyclic dimer were used as cyclic oligomers. In the same manner as in Example 1, an esterification reaction, a ring-opening reaction, and a polycondensation reaction were performed. As a result, 53.9 kg of copolyester was obtained.

Comparative Example 3
The amount charged in Example 1 was 6.6 kg of isophthalic acid, 16.2 kg of sebacic acid, 3.7 kg of ethylene glycol, and 9.4 kg of neopentyl glycol (isophthalic acid: sebacic acid: ethylene glycol: neopentyl glycol = 33.3: 66.7: 50: 75 (molar ratio), (G) / (A) = 1.25 (molar ratio)), and 31.8 kg of a low polymer was obtained. Next, 5.7 kg (17.9 parts by mass) of isophthalic acid-ethylene glycol cyclic dimer and 10.3 kg (32.3 parts by mass) of isophthalic acid-neopentyl glycol cyclic dimer were used as cyclic oligomers. In the same manner as in Example 1, an esterification reaction, a ring-opening reaction, and a polycondensation reaction were performed. As a result, 43.8 kg of copolyester was obtained.

  Table 1 shows the esterification reaction time, ring-opening reaction time, and polycondensation reaction time required in the production of the polyesters of Examples 1-4 and Comparative Examples 1-3.

As is apparent from Table 1, in the production methods of Examples 1 to 3, the reaction time before the condensation polymerization reaction step, that is, the total time of the esterification reaction time and the condensation polymerization reaction time was 3.5 hours.
On the other hand, in Comparative Example 1, since the cyclic oligomer was not added, the esterification reaction time required 5.0 hours, and the production efficiency was poor. In Comparative Example 2, since the addition amount of the cyclic oligomer was too small, the esterification reaction time required 4.5 hours, and the production efficiency was poor. In Comparative Example 3, since the amount of cyclic oligomer added was too large, the ring-opening reaction took 2.0 hours, and the production efficiency was poor.

Claims (1)

The group which consists of dicarboxylic acid (A) which has aromatic dicarboxylic acid and C6-C12 aliphatic dicarboxylic acid as a main component, and ethylene glycol, neopentyl glycol, propylene glycol, 1,6-hexanediol, and cyclohexanedimethanol A method for producing a polyester comprising a glycol (G) comprising as a main component a glycol selected from the following, which comprises the following steps.
Esterification reaction step: a step of esterifying the dicarboxylic acid (A) and the glycol (G) to obtain a low polymer thereof,
Ring-opening reaction step: 100 parts by mass of the low polymer obtained in the esterification reaction step and 5 to 40 parts by mass of a cyclic oligomer composed of the same monomer as that constituting the low polymer are mixed to carry out the ring-opening reaction. Process to perform and polycondensation reaction process: Process to perform polycondensation reaction of product after ring-opening reaction