JPH059273A - Copolyester and method for producing the same - Google Patents

Abstract

(57) [Summary] [Object] To provide a copolyester which is a biodegradable polymer. [Structure] Consists of the following structural units [I] and [II],
[I] / [II] = 97/3 to 3/97 (molar ratio), a weight average molecular weight of 10,000 or more copolymerized polyester and the polyester are represented by the following general formulas [II] and [IV]. A method for producing the compound by polymerizing

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolyester which is a biodegradable polymer expected as a polymeric material for environmental problems and a medical polymeric material, and a method for producing the same.

[0002]

2. Description of the Related Art Biodegradable polymers have been investigated as polymeric materials for environmental problems and medical polymeric materials. It is known that lactic acid and mandelic acid are directly copolymerized as a copolymerized polyester composed of structural units of the following formula [I] and the following formula [II] (H. Fuknz
aki Eur. Poly. J. 26, 1273 (19
90)).

[0003]

However, the copolymerized polyester produced by the above-mentioned production method has a molecular weight of 5,000 or less, and although it can be used in a drug delivery system (DDS), it is widely used as a polymer material for environmental protection or medical use. Not available. Development of a method for producing a polymer having a higher molecular weight has been expected to be widely used for these purposes.

[0004]

Therefore, as a result of diligent studies on a method for producing a polymer having the above-mentioned two kinds of constitutional units, the compound represented by the following general formula [III] and the following general formula [IV] was used as a catalyst. It was found that a high molecular weight polymer can be produced more easily by copolymerizing in the presence of
The present invention has been reached. That is, the gist of the present invention is a unit of the following general formula [I], —O—CHR—CO— [I] (in the formula [I], R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) and the following: Unit of the general formula [II] —O—CHAr—CO— [II] (In the formula [II], Ar is a phenyl group, alkyl,
It may be substituted with alkoxy, acetyl, acetoxy, halogen, nitro or phenyl groups. ) As a structural unit, and the molar ratio [I] / [II] is 97/3 to 3 /
97, and a weight average molecular weight of 10,000 or more, a copolyester and a compound represented by the general formula [III]

[0005]

[Chemical 3]

(Formula [III] R is the same as formula [I]) and compounds represented by general formula [IV]

[0007]

[Chemical 4]

(Wherein Ar is the same as in the formula [II] in the formula [IV]) is polymerized in the presence of a catalyst.

The present invention will be described in detail below. The polymerization reaction of the present invention is carried out in the presence of a catalyst, and specific examples of the catalyst that can be used include tin compounds, aluminum compounds, antimony compounds and titanium compounds, and tin compounds are particularly preferable. The polymerization reaction is carried out in the presence or absence of a solvent. When a solvent is used, it dissolves the compound represented by the general formula [III] or [IV] and does not inactivate the catalyst. If so, both can be used. Specific examples include tetrahydrofuran, chloroform, orthodichlorobenzene, dioxane and the like.

The composition of the copolymer is such that the constitutional unit of the formula [II] is 3 to 97 mol%, preferably 3 to 50 mol%, more preferably 5 to 30 mol%. When the amount of the structural unit of the formula [II] is large, the biodegradability of the copolymer is deteriorated, which is not preferable. When the amount of the structural unit of the formula [II] is small, the mechanical properties of the copolymer are deteriorated. Absent.

The polymerization temperature is 0 to 300 ° C., preferably 50.
~ 250 ° C. Examples of the compound represented by the general formula [III] include compounds in which R is an ethyl group, an isopropyl group, an n-propyl group, an n-butyl group, and the like in addition to lactide and glycolide. Lactide is preferred because of easy availability of raw materials. Examples of the compound represented by the general formula [IV] include compounds in which the Ar group is a p-tolyl group, a 2,4-xylyl group, a p-methoxyphenyl group, a 2,5-dichlorophenyl group, and the like in addition to mandelide. Mandelid is particularly preferred.

The molecular weight is generally 10,000 as a weight average molecular weight when a polymer is used as a molding material.
0 or more, preferably 20,000 or more, more preferably 3
A polymer having a degree of polymerization of 10,000 or more is required due to its initial mechanical properties. By the method of the present invention in which the compounds represented by the general formulas [III] and [IV] are polymerized in the presence of a catalyst, the general formula [I] and the formula [II] having a weight average molecular weight of 10,000 or more are regarded as constitutional units. A copolymerized polyester that can be easily obtained.

[0013]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Example 1 Mandelito's Synthetic Reflux Cooler, equipped with a Dean-Stark trap 5
200 ml of benzene, 23.7 g (150 mmol) of L-mandelic acid and 1.05 g (5.4 mmol) of p-toluenesulfonic acid were added to a 00 ml flask and refluxed.
The water accumulated in the trap was removed at any time. After refluxing for 60 hours, the suspension was filtered while hot, and the residue was washed with dichloromethane and dried to obtain a white powder. IR of products and raw materials
And NMR are shown in FIGS. 1 and 2. ¹ H-NMR shows 6.85 ppm of singlet CH, 7.6 ppm
There was absorption of C ₆ H _{5 by} Martipret.

Example 2 Synthesis of Copolymerized Polyester 0.5 g of mandelide and 2.42 g of 1-lactide were added and the atmosphere was replaced with nitrogen. After heating to 200 ° C. and melting, 0.753 g of tin octylate was added. The reaction system was depressurized to 1 mmHg and heated at the same temperature for 1.5 hours. After the reaction, the product was dissolved in 15 ml of chloroform and reprecipitated in 200 ml of ether. The obtained amount was 2.4 g and the yield was 83%. After that, ether was removed by decantation and dried to obtain a powdery copolymer. ¹ H-NMR measured in deuterated chloroform is shown in FIG. The doublet peak at 1.58 ppm, the quartet peak at 5.16 ppm, and the broad peak at 6.04 ppm are 7.42.
A broad multiplet peak was found at ppm. The number average molecular weight of the copolymer was 18,000 and the weight average molecular weight was 40,000. The molecular weight was determined by gel permeation chromatography (GPC). GPC was performed using Tosoh HLC-802A type, TSK gel G4000H8 was used as a column, and TSK-CP8000 was used as a data processor. An RI detector was used as a detector for measurement. Tetrahydrofuran was used as the solvent, and the temperature was measured at 38 ° C.

[0015]

EFFECT OF THE INVENTION The high molecular weight copolyester of the present invention, unlike the conventional low molecular weight copolyester, has sufficient mechanical properties and can be used as a wide range of molding materials. Further, according to the production method of the present invention, a high-molecular-weight biodegradable copolyester useful as a molding material can be easily produced.

[Brief description of drawings]

FIG. 1 is an IR spectrum diagram of a product and a raw material in Example 1.

FIG. 2 Product and raw material ¹ H-NM in Example 1
R spectrum diagram

FIG. 3 is a ¹ H-NMR spectrum diagram of the product in Example 2.

Claims (2)

[Claims] 1. A unit of the following formula [I], —O—CHR—CO— [I] (in the formula [I], R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) and the following formula [II] ] -O-CHAr-CO- [II] (In formula [II], Ar is a phenyl group, alkyl,
It may be substituted with alkoxy, acetyl, acetoxy, halogen, nitro or phenyl groups. ) As a structural unit, and the molar ratio [I] / [II] is 97/3 to 3 /
97, and the weight average molecular weight is 10,000 or more, The copolyester characterized by the above-mentioned. 2. A compound represented by the general formula [III]: (In the formula [III], R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) and a compound represented by the general formula [IV]: (In the formula [IV], Ar is a phenyl group, alkyl,
It may be substituted with alkoxy, acetyl, acetoxy, halogen, nitro or phenyl groups. 2.) The method for producing a copolyester according to claim 1, wherein the polymerization is carried out in the presence of a catalyst.