JPH10204159A - Aliphatic polyester and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aliph. polyester with a reduced odor by reducing the content of units derived from an aliph. caboxylic acid having a specified number of carbon atoms in the polyester to a specified level or lower by polymerizing a raw material contg. a reduced amt. of such a carboxylic acid or by converting such a carboxylic acid into another compd. during polymn. SOLUTION: A lactone selected from among β-propiolactone, ε-caprolactone, etc., is used as a material for this aliph. polyester. ε-Caprolactone is mixed with ethylene glycol, a polymn. catalyst, and a carbodiimide [e.g. N,N'-(2,6- diisopropyl)phenylcarbodiimide] which can convert and aliph. carboxylic acid into another compd. The resultant mixture is subjected to thermal polymn. in a nitrogen atmosphere to give a polymer having a content of 2-6C aliph. carboxylic acids of 5ppm or lower and emitting a low odor. Other examples of the raw material for the polyester are dimethyl-β-propiolactone and γ- butyrolactone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aliphatic polyester having a reduced odor component and a method for producing an aliphatic polyester having a reduced odor component.

[0002]

2. Description of the Related Art Conventionally, films, sheets or foam molded articles made of thermoplastic resins, for example, polyolefin resins, polyvinyl chloride resins, and polystyrene resins, utilize their properties to make use of packaging materials, agricultural materials, and industrial materials. It is used for various purposes such as materials. However, molded articles made of these thermoplastic resins are chemically stable, and once left in the natural world, it takes an extremely long time to decompose them, leading to the problem of destruction of the natural environment and pollution. Was. Therefore, the problem of their disposal has become a kind of social problem in recent years. In view of such circumstances, in recent years, various degradable plastics friendly to the natural environment have been developed. For example, those obtained by adding a starchy substance such as corn starch to a polyolefin to impart biodegradability, poly-ε-caprolactone, polyhydroxybutyrate / polyhydroxyvalerate copolymers, aliphatic polyesters such as polylactic acid, modified A composition comprising starch and modified polyvinyl alcohol, a photodegradable plastic having a carbonyl group introduced into a polymer molecular chain, and the like have been reported. Among them, poly-ε
Aliphatic polyesters such as caprolactone, polyhydroxybutyrate / polyhydroxyvalerate copolymer, and polylactic acid have been confirmed to be completely decomposable, and have recently attracted attention. However, there is a problem that some of these resins have a lot of odors and their applications are limited. Japanese Patent Publication No. 1-457 relates to the production of caprolactone esters having reduced odor.
Although there is No. 0, this relates to a caprolactone ester having a pentamer or less, and in particular, a production method for reducing the odor of an aliphatic polyester and an aliphatic polyester having a reduced odor have not been found from previous studies.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aliphatic polyester having a reduced odor-generating component and a method for producing an aliphatic polyester having a reduced odor-generating component. And

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies with the aim of providing an aliphatic polyester having a low odor, and as a result, the aliphatic carboxylic acid contained in the aliphatic polyester has a specific content. It has been found that the odor is improved by the following, and the present invention has been completed. Until now, there has been no clear way to improve odor despite the demands of the market. However, as shown in the present invention, when the content of the aliphatic carboxylic acid having 2 to 6 carbon atoms contained in the aliphatic polyester is 50 ppm or less, preferably 30 ppm or less, the odor becomes good. The present invention provides an aliphatic polyester having a low odor component, and is particularly characterized in that the aliphatic polyester is poly-ε-caprolactone.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A component causing an odor of an aliphatic polyester is an aliphatic carboxylic acid having 2 to 6 carbon atoms,
50 ppm of the content of the aliphatic carboxylic acid having 2 to 6 carbon atoms
The odor of the aliphatic polyester can be reduced by the following. Among the aliphatic polyesters with a low odor emitting component of the present invention, in particular, as a means for producing an aliphatic polyester characterized in that the aliphatic polyester is poly-ε-caprolactone,
(1) Polymerization is carried out using an aliphatic carboxylic acid having 2 to 6 carbon atoms contained in all the raw materials having a specific amount or less. (2) Pretreatment of the raw material (for example, distillation or deoxidation)
Then, polymerization is carried out using an aliphatic carboxylic acid having 2 to 6 carbon atoms in which the amount has become a specific amount or less. (3) There is a method of polymerizing under conditions (for example, a system to which carbodiimide or the like is added) under which the aliphatic carboxylic acid having 2 to 6 carbon atoms contained in the raw material changes into another compound during the polymerization reaction. . The production method of the present invention may employ any of these methods. By reducing the content of the aliphatic carboxylic acid having 2 to 6 carbon atoms contained in the aliphatic polyester by these production methods to 50 ppm or less, the odor of the produced aliphatic polyester is remarkably reduced. Here, the content of the aliphatic carboxylic acid having 2 to 6 carbon atoms can be measured by a gas chromatograph mass spectrometer. Specific examples of the aliphatic polyester according to the present invention include lactone polyesters (for example,
Poly-β-propiolactone, polydimethyl-β-propiolactone, poly-γ-butyrolactone, poly-γ-
Valerolactone, poly-γ-caprolactone, poly-δ
Valerolactone, poly-δ-caprolactone, poly-
ε-caprolactone). Specific examples of the aliphatic carboxylic acids having 2 to 6 carbon atoms according to the present invention include acetic acid, propionic acid, acrylic acid, butyric acid, crotonic acid, vinyl acetic acid, isobutyric acid, methacrylic acid, valeric acid, isovaric acid. Folic acid, 2-methylbutyric acid, 2-pentenoic acid, 4
-Pentenoic acid, tiglic acid, caproic acid, 2-methylvaleric acid, 3-methylvaleric acid, isocaproic acid, 2-hexenoic acid, 3-hexenoic acid and the like. Specific examples of the carbodiimide according to the present invention include N,
N'-dicyclohexylcarbodiimide, N, N'-
(2,6-diisopropyl) phenylcarbodiimide and the like. Specific examples of the aliphatic polyester raw material according to the present invention include lactones (for example, β-propiolactone, dimethyl-β-propiolactone, γ-butyrolactone, γ-valerolactone, γ-valerolactone).
-Caprolactone, δ-valerolactone, δ-caprolactone, ε-caprolactone, etc.).

[0006]

EXAMPLES Hereinafter, the present invention will be described with reference to more specific examples, but the present invention is not limited to these examples.

Example 1 An acid value of about 0.20 mg KO
H / g, 100 ml (902.4 mmol) of ε-caprolactone having a water content of 150 ppm were added under nitrogen atmosphere to 1
Heat to 80 ° C and add 0.066 ml of ethylene glycol
(1.20 mmol), 0.1 × 10-1 ml of tri (2-ethylhexanoate) butyltin (0.0180 m
mol), 0.515 g (1.42 mmol) of 1,3-di (2,6-isopropylphenyl) carbodiimide
Was added to synthesize polycaprolactone. The polymerization was carried out for 2 hours. At this time, the conversion was 99.5%, and the number average molecular weight was 48,000. The odor of this polymer was good as shown in Table 1. As a result of analysis, the content of the aliphatic carboxylic acid having 2 to 6 carbon atoms was 10 ppm. In addition, the mark 示 す shown in Table 1 has a good odor (almost no odor),
An X mark means that the odor is poor (it has a considerable odor).

Example 2 5% by weight of Kyoward 500-7 (synthetic hydrotalcite: manufactured by Kyowa Chemical Industry Co., Ltd.) was added to ε-caprolactone and stirred for 2 hours.
The acid value of caprolactone was deoxidized from about 0.20 mgKOH / g to 0.03 mgKOH / g, and dried with molecular sieve. Obtained acid value 0.03 mg KOH
/ G, ε-caprolactone 10 having a water content of 60 ppm
0 ml (902.4 mmol) in a nitrogen atmosphere for 180
C. and heated to 0.1 ml of ethylene glycol (1.8
1 mmol), 0.2 × 10-2 ml (0.0036 mmol) of tri (2-ethylhexanoate) butyltin
Was added to synthesize polycaprolactone. The polymerization was carried out for 3 hours. At this time, the conversion was 99.5%, and the number average molecular weight was 45,800. The odor of this polymer was good as shown in Table 1. As a result of analysis, the content of the aliphatic carboxylic acid having 2 to 6 carbon atoms was 5 ppm.

(Comparative Example 1) An acid value of about 0.20 mg KO
H / g, ε-caprolactone 1 having a water content of 150 ppm
00 ml (902.4 mmol) was added under nitrogen atmosphere to 18
Heat to 0 ° C and add 0.066 ml of ethylene glycol
(1.20 mmol), 0.1 × 10-1 ml of tri (2-ethylhexanoate) butyltin (0.0180 m
mol)) to synthesize polycaprolactone. The polymerization was carried out for 6 hours, at which time the polymerization rate was 99.5% and the number average molecular weight was 48,000. The odor of this polymer was poor as shown in Table 1. As a result of analysis, the content of the aliphatic carboxylic acid having 2 to 6 carbon atoms was 100 ppm.

[0010]

[Table 1]

[0011]

The aliphatic polyester of the present invention has a low odor of resin which has been difficult to reduce conventionally, and has a wide industrial application range.

Claims (8)

[Claims] 1. An aliphatic polyester having a low odor component. 2. The aliphatic polyester according to claim 1, wherein the aliphatic polyester is poly-ε-caprolactone. 3. An aliphatic polyester according to claim 1, wherein the odorous component is an aliphatic carboxylic acid having 2 to 6 carbon atoms. 4. An aliphatic polyester, wherein the aliphatic carboxylic acid having 2 to 6 carbon atoms according to claim 3 is 50 ppm or less. 5. The method for producing an aliphatic polyester according to claim 1, wherein the polymerization is carried out using a raw material in which the amount of the aliphatic carboxylic acid in the raw material is reduced, or the aliphatic carboxylic acid is converted into another during the polymerization reaction. A process for producing an aliphatic polyester, which comprises converting the compound into a compound. 6. A method for producing an aliphatic polyester, wherein the aliphatic polyester according to claim 5 is poly-ε-caprolactone. 7. A method for producing an aliphatic polyester according to claim 3, wherein the odor-producing component is an aliphatic carboxylic acid having 2 to 6 carbon atoms. 8. A process for producing an aliphatic polyester, wherein the aliphatic carboxylic acid having 2 to 6 carbon atoms according to claim 3 is 50 ppm or less.