JP2002179897A - Method for imparting biodegradability to thermoplastic aromatic polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit and improve biodegradability of an aromatic polyester by a simple technique. SOLUTION: A swellable phyllosilicate treated with, e.g. a quaternary ammonium ion is dispersed in a thermoplastic aromatic polyester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for biodegrading a thermoplastic aromatic polyester.

[0002]

2. Description of the Related Art Polyethylene terephthalate (PE)
T), thermoplastic aromatic polyesters such as polyethylene naphthalate (PEN) and polybutylene terephthalate (PBT) have excellent heat resistance, mechanical properties, chemical resistance, etc., so that fibers, films, resins, etc. As widely used.

[0003] Conventionally, biodegradable polyesters have been studied mainly on aliphatic polyesters. On the other hand, it is generally considered difficult to decompose the aromatic polyester. ("Biodegradable polymer material"
263-276 (1990), Industrial Research Committee, Tokyo). However, some biodegradable polymers containing an aromatic component have also been studied. For example, WO95-14740 discloses a copolymer of sulfoisophthalic acid and an aliphatic component. However, there is no disclosure of a method for enhancing biodegradability by dispersing an inorganic component as in the present invention.

In aliphatic polyesters such as polycaprolactone, it has been reported that biodegradability is improved by dispersing a swellable layered silicate at a molecular level (ANTEC '99, Biodegradable P).
plastics 99 Conference) has not been studied in aromatic polyesters.

[0005]

As described above, biodegradation of aromatic polyester is a very difficult technique. An object of the present invention is not to improve the structure of the aromatic polyester by copolymerization, but to develop and improve the biodegradability of the aromatic polyester by a simple method.

[0006]

Means for Solving the Problems The present inventors have found that the biodegradability of an aromatic polyester can be improved by highly dispersing a swellable layered silicate in a thermoplastic aromatic polyester, and have made the present invention. It was completed.

That is, the present invention is as follows. 1. A method for imparting biodegradability to a thermoplastic aromatic polyester by dispersing a swellable layered silicate in the thermoplastic aromatic polyester. 2. The method of claim 1, wherein the swellable layered silicate has been treated with an organic onium ion. 3. The method according to the above 2, wherein the organic onium ion is a quaternary ammonium ion. 4. The method according to the above 3, wherein the quaternary ammonium ion is represented by the following formula (1).

[0008]

Embedded image

(In the formula (1), R ₁ , R ₂ , R ₃ and R ₄ are each independently an alkyl group having 1 to 30 carbon atoms or a polyalkylene oxide group.) The method according to any one of the above 1 to 4, wherein the swellable layered silicate is montmorillonite or swellable mica. 6. The method according to any one of the above 1 to 5, wherein the content of the swellable phyllosilicate in the polyester composite material is 0.5 to 10% by weight.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The swellable phyllosilicate used in the present invention is a phyllosilicate having a cation exchange ability and exhibiting the property of swelling by taking in water between layers. Examples of the smectite-based clay mineral include hectorite, saponite, stevensite, beidellite, montmorillonite, natural or chemically synthesized ones thereof, and substituted, derivative, or mixtures thereof. Examples of the swellable mica include synthetic swellable mica having chemically-synthesized layers, for example, Li and Na ions, or a substituted body, a derivative or a mixture thereof.

In the present invention, it is preferable to use the swellable layered silicate treated with an organic onium ion. The organic onium ion used is represented by the following formula (1)

[0012]

Embedded image

(Wherein, R ₁ , R ₂ , R ₃ and R ₄ are each independently an alkyl group having 1 to 30 carbon atoms or a polyalkylene oxide group). preferable. Here, the alkyl group having 1 to 30 carbon atoms is preferably an alkyl group having 1 to 18 carbon atoms.

The organic onium ion represented by the above formula (1) is preferably a quaternary ammonium ion. Specifically, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, oleyltrimethylammonium chloride, didodecyldimethylammonium chloride, ditetradecyldimethylammonium chloride, dihexadecyldimethylammonium Chloride, dioctadecyl dimethyl ammonium chloride,
Dioleyldimethylammonium chloride dodecyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, oleyldimethylbenzylchloride, hydroxypolyoxyethylene dodecyldimethylammonium chloride, hydroxypolyoxyethylene Tetradecyl dimethyl ammonium chloride, hydroxy polyoxyethylene hexadecyl dimethyl ammonium chloride, hydroxy polyoxy ethylene octadecyl dimethyl ammonium chloride, hydroxy polyoxy ethylene oleyl dimethyl ammonium chloride, dihydroxy polyoxy ethylene dodecyl Tylammonium chloride, dihydroxypolyoxyethylenetetradecylmethylammonium chloride, dihydroxypolyoxyethylenehexadecylmethylammonium chloride, dihydroxypolyoxyethyleneoctadecylmethylammonium chloride, dihydroxypolyoxyethyleneoleylmethylammonium chloride, dihydroxypolyoxypropylenetetradecylmethylammonium Chloride, dihydroxypolyoxybutylenetetradecylmethylammonium chloride.

In the method of treating the swellable phyllosilicate with organic onium ions, usually, 1 part by weight of the swellable phyllosilicate and 1 to 10 parts by weight of organic onium ions are mixed in water and then dried. The amount of water is 1 to 100 times that of the swellable phyllosilicate. The temperature at the time of mixing is 30 ° C to 70 ° C,
The mixing time is preferably 0.5 to 2 hours. As the drying conditions, drying under normal pressure at 70 to 100 ° C. for 3 days and vacuum drying for 2 days are preferable.

Specific examples of the thermoplastic aromatic polyester used in the present invention include polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and polyethylene isophthalate. Polyesters containing a polycondensate of an aromatic dicarboxylic acid and a diol as the main repeating component, such as -terephthalate copolymer, polybutylene isophthalate-terephthalate copolymer, polycyclohexylene dimethylene isophthalate-terephthalate copolymer, etc. But is not limited to these.

As the aromatic dicarboxylic acid component which is a raw material monomer for the aromatic polyester, specifically, all known dicarboxylic acids, dicarboxylic acid esters, hydroxycarboxylic acids and diols which are known aromatic polyester raw materials can be used. is there. For example, terephthalic acid, orthophthalic acid, chlorophthalic acid, nitrophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid,
5-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid acid,
4,4'-diphenylisopropylidene dicarboxylic acid, 1,2-
Aromatic dicarboxylic acids such as bis (4-carboxyphenoxy) -ethane, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium sulfoisophthalic acid, oxalic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacin Examples thereof include acids, dodecandioic acid, octadecanedicarboxylic acid, dimer acids, aliphatic dicarboxylic acids such as maleic acid and fumaric acid, and cyclic aliphatic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid. Examples of the dicarboxylic acid ester include a methyl ester of the above dicarboxylic acid. Examples of the hydroxycarboxylic acid include aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid, p-hydroxyethoxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 4′-hydroxy-biphenyl-4-carboxylic acid. .

Examples of the diol which is a raw material monomer of the aromatic polyester include ethylene glycol, propylene glycol, 1,3-butanediol 1,4-butanediol, 2,2-dimethylpropanediol, neopentyl glycol, 1,5 -Pentadiol, 1,6-hexanediol,
1,8-octanediol, 1,10-decanediol 1,4-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, 1,2-cyclohexane dimethanol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, octadiol Methylene glycol, diethylene glycol, dipropylene glycol, polyethylene glycol, hydroquinone, resorcinol, bisphenol A and 2,2-bis (2'-hydroxyethoxyphenyl)
Propane.

In these aromatic polyesters, a copolymer component may be introduced or a terminal group may be modified as required.
Examples of such a copolymer component include an aliphatic dicarboxylic acid, an aliphatic oxycarboxylic acid component, and an aromatic diol component. The amount of the copolymer component to be introduced is not particularly limited, but is preferably as small as possible in order to maintain the original physical properties of the aromatic polyester. Preferably it is 0.2 mol or less, more preferably 0.1 mol or less, per 1 mol of the monomer component of the aromatic polyester. As the terminal group, a known terminal modifier or polymerization accelerator can be used.

A method in which a polymer containing a large amount of a copolymer component is used as a masterbatch and mixed with a polymer containing no copolymer component to obtain a desired aromatic polyester can also be used. In this case, the mixed polymer is preferably uniform, and preferably has a uniform composition by transesterification or the like.

As a method for producing an aromatic polyester,
Any known method can be used. For example, the dicarboxylic acid ester raw material and the diol raw material are transesterified at a temperature of 180 to 250 ° C. using an ester exchange catalyst such as calcium acetate while distilling off alcohol, and then 250 to 29.
There is a method in which melt polymerization is carried out at 0 ° C. for 1 to 5 hours while distilling out a diol under a reduced pressure of 0.5 mmHg or less using a polymerization catalyst such as germanium dioxide or antimony trioxide to obtain a polyester.

The above polyester is phenol / 1,1 ', 2,
Dissolved in 2'-tetrachloroethane = 60/40 (weight ratio) solvent, 3
When the measurement is performed at 5 ° C., it is preferable to use one having a solution viscosity of 0.6 to 1.2.

The ratio (content) of the swellable layered compound in the polyester composite material in the present invention is 0.5 to 0.5%.
The content is preferably 10% by weight, and more preferably 1 to 5% by weight, whereby higher dispersibility can be obtained.

As a method of dispersing the swellable layered compound in the polymer, for example, a swellable layered silicate is added at the time of polymerization of the thermoplastic aromatic polyester and uniformly dispersed, or the swellable layered silicate is dispersed in the polymer. The method of dispersing the layered silicate by melt kneading or solution dispersion can be adopted.

In a state where these swellable layered compounds are dispersed, (0) of the swellable layered silicate measured by X-ray analysis is used.
It is preferable that the diffraction peak derived from the bottom reflection of the 01) plane shift to a low angle of incidence, that is, the state in which the distance between the planes is increased, in order to achieve the object of the present invention.

The term "biodegradation" as used in the present invention means that it is decomposed by an aggregate (mixed state) of ordinary microorganisms represented by activated sludge and the like, and the solution viscosity of the polyester is significantly reduced. Those having a biodegradation rate of 3% or more in 2 weeks are preferred.

The aromatic polyester disclosed in the present invention has physical properties similar to ordinary aromatic polyesters, for example, mechanical strength and heat resistance, and can also have biodegradability. Use of biodegradable plastics, such as agricultural films, seedling pots, agricultural and horticultural applications such as seed coating and horticultural ropes,
It can be used for industrial materials such as sandbags, ropes, soil improvement materials, and food packaging materials. Further, since the gas barrier property is expected to be improved by dispersing the swellable layered viscosity compound, it can be used for food films and beverage bottles having both gas barrier properties and biodegradability.

[0028]

According to the present invention, it is important to find that a polyester composite material in which a swellable layered silicate is dispersed exhibits biodegradability. This polyester composite material is expected to promote the biodegradation of the polyester because the swellable layered silicate is highly dispersed in the polyester, and to further improve the gas barrier property. Further, since the dispersibility in polyester is improved and the mechanical strength and heat resistance are expected to be improved without losing transparency, applications such as a biodegradable gas barrier film are considered.

[0029]

The following examples further illustrate the details of the present invention.

The montmorillonite used in this example was Na
nocor, dihydroxypolyoxyethylene oleylmethylammonium chloride is Takemoto Yushi Co., Ltd., phenol, 1,1 ', 2,2'-tetrachloroethane, glucose, potassium dihydrogen phosphate, and bactopeptone is Kanto Chemical
Co., Ltd., PET (polyethylene terephthalate, FK-OM) is Teijin
Co., Ltd. was used.

Quaternary ammonium ion of swellable layered silicate
Treated montmorillonite 100g, dihydroxy polyoxyethylene oleyl methyl ammonium chloride 100g and water 10L
Was added, and the mixture was stirred at room temperature for 2 hours, and a crude product was obtained by filtration. Further, after washing three times with 10 L of water, hot air drying was performed at 100 ° C. for 3 days and vacuum drying was performed for 2 days to obtain montmorillonite treated with quaternary ammonium ions. Confirmation is
It was performed by X-ray analysis.

Measurement of interlayer distance of swellable phyllosilicate The interlayer distance of swellable phyllosilicate was measured using a wide-angle X-ray analyzer (Rigaku Denki Co., Ltd. CN2155). Was determined from the diffraction peak derived from the bottom reflection.

[0033] In accordance with optimized test culture preparation method described in the conditioned JIS standard K6950 activated sludge, were prepared activated sludge. This optimized test culture is highly buffered and contains many mineral nutrients. This is necessary to keep the pH of the system under test constant even at high test sample concentrations. This culture contains approximately 2,400 mg / l phosphorus and 50 mg / l nitrogen and is therefore suitable for test material concentrations up to 2000 mg / l organic carbon.

Specifically, solution A: inorganic potassium dihydrogen phosphate 37.5 g, disodium hydrogen phosphate dihydrate 8
7.3 g and 2 g of ammonium chloride are dissolved in water, and the total amount is 1
Make up to 000 ml. Solution B: Dissolve 22.5 g of magnesium sulfate heptahydrate in water to make the total volume 1000 ml.
Solution C: Dissolve 36.4 g of calcium chloride dihydrate in water to make the total volume 1000 ml. D solution: iron chloride (II
I) 0.25 g of hexahydrate is dissolved in water, and the total amount is 1000
to ml. Then, 100 ml of solution A and solutions B to D
, 197 g of water, 8 g of water and 1 g of bactopeptone as a carbon source to prepare a test culture solution.

Biodegradability Test The polyester composite material was immersed in activated sludge at 50 ° C. for 2 weeks with aeration.

Solution Viscosity Measurement The polyester composite material was dissolved in a phenol / 1,1 ′, 2,2′-tetrachloroethane = 60/40 (weight ratio) solvent and measured at 35 ° C.

Example 1 5 g of PET (FK-OM), 0.21 g of montmorillonite (quaternary ammonium ion treatment) (3 parts by weight of PET)
Weight%) phenol / 1,1 ', 2,2'-tetrachloroethane = 6 /
It was dissolved in a 4 (weight ratio) mixed solvent, cast on a Teflon (registered trademark) plate, dried with hot air at 80 ° C. for 1 hour, and vacuum-dried for 24 hours to obtain a 50 μm thick film. The dispersibility of montmorillonite in polyester was evaluated by X-ray analysis. In addition, it was immersed in activated sludge at 50 ° C for 2 weeks while aeration was performed, and a biodegradability test was carried out.

Comparative Example 1 5 g of PET (FK-OM) was mixed with phenol /
Dissolved in a mixed solvent of 1,1 ', 2,2'-tetrachloroethane = 6/4 (weight ratio), cast on a Teflon plate, dried with hot air at 80 ° C for 1 hour, and vacuum dried for 24 hours, then a 50μm thick film I got It was immersed in activated sludge for 2 weeks while being aerated, and a biodegradability test was performed. The biodegradability was evaluated based on the change in solution viscosity of the polymer before and after immersion.

[0039]

[Table 1]

[0040] * The biodegradation rate = - than (biodegradation previous η _{sp / c} η _{sp / c} after biodegradation) / (biodegradation previous eta _{sp / c)} Example 1 and Comparative Example 1, swellable layered It was found that a polyester composite material obtained by dispersing a silicate in a polyester exhibited high biodegradability.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Takeyuki Kawaguchi 2-1 Hinode-cho, Iwakuni-shi, Yamaguchi F-term in the Iwakuni Research Center Teijin Limited 4J002 CF041 CF051 CF061 CF071 CF081 DJ006 FB086

Claims (6)

[Claims] 1. A method for imparting biodegradability to a thermoplastic aromatic polyester by dispersing a swellable layered silicate in the thermoplastic aromatic polyester. 2. The method for imparting biodegradability to a thermoplastic aromatic polyester according to claim 1, wherein the swellable layered silicate has been treated with an organic onium ion. 3. The method for imparting biodegradability to a thermoplastic aromatic polyester according to claim 2, wherein the organic onium ion is a quaternary ammonium ion. 4. A quaternary ammonium ion represented by the following formula (1):
The method for imparting biodegradability to the thermoplastic aromatic polyester according to claim 3, wherein Embedded image (In the formula (1), R ₁ , R ₂ , R ₃ and R ₄ are each independently an alkyl group having 1 to 30 carbon atoms or a polyalkylene oxide group.) 5. The method for imparting biodegradability to a thermoplastic aromatic polyester according to claim 1, wherein the swellable layered silicate is montmorillonite or swellable mica. 6. The thermoplastic aromatic polyester according to claim 1, wherein the content of the swellable phyllosilicate in the polyester composite material is 0.5 to 10% by weight. How to give.