JP2016193989A - Method for producing polyester having branched structure, and polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a method for simply and efficiently producing a polyester having a branched structure capable of increasing molecular weight, while effectively inhibiting gelation even when a hydroxy alkanoic acid having a secondary hydroxyl group is contained as a polymerization component; and the polyester.SOLUTION: The method for producing polyester comprises the steps of: preparing a hydroxyl group-containing polyester precursor at least having a dicarboxylic acid or reactive derivative thereof, a diol, and a hydroxy alkanoic acid or alkyl ester thereof as a polymerization component; and performing chain elongation by reacting the polyester precursor and a polycarboxylic acid or reactive derivative thereof.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a polyester containing a skeleton derived from a hydroxyalkanoic acid having a secondary hydroxyl group and having a branched structure, and the polyester.

  In recent years, biodegradable plastics that are decomposed by natural microorganisms have attracted attention. Typical biodegradable plastics include, for example, polyhydroxyalkanoic acids having secondary hydroxyl groups such as polylactic acid and poly (3-hydroxybutyric acid). Since polylactic acid can be synthesized by chemical polymerization using lactic acid (for example, L-lactic acid) as a raw material, many highly functional polylactic acids have been synthesized.

  In Japanese Unexamined Patent Publication No. 2014-15578 (Patent Document 1), in the absence of a solvent, a polylactic acid prepolymer containing a lactic acid oligomer having a terminal carboxyl group ratio exceeding 80 mol% and a polyisocyanate compound are converted into an amidation catalyst. Describes a process for producing high molecular weight polylactic acid by reaction in the presence of. In the examples of this document, a lactic acid is polymerized to produce a polylactic acid oligomer, and a polylactic acid prepolymer in which a terminal hydroxyl group is converted to a carboxyl group by a reaction between the produced lactic acid oligomer and succinic anhydride is prepared. The prepared polylactic acid prepolymer is reacted with hexamethylene diisocyanate to obtain a high molecular weight polylactic acid chain-extended through an amide bond. However, lactic acid has a low secondary hydroxyl group reactivity, and even when lactic acid oligomers are produced, it takes a long time at high temperatures. In addition, this method also requires a step of converting a hydroxyl group into the terminal carboxyl group, so that it cannot be easily increased in molecular weight, and productivity is low. Furthermore, although heat resistance can be improved by an amide bond, flexibility is not sufficient because it is mainly formed of units derived from lactic acid.

  On the other hand, a polyester resin containing a hydroxyalkanoic acid having a secondary hydroxy group, such as polylactic acid, a diol, and a dicarboxylic acid as a polymerization component is also known. In such a resin production method, highly reactive dicarboxylic acid and diol are contained in the polymerization component, so that flexibility can be improved and molecular weight can be increased as compared with a homopolymer of hydroxyalkanoic acid.

  For example, in JP-A-9-110971 (Patent Document 2), in the presence of a germanium compound as a catalyst, an aliphatic dicarboxylic acid, an aliphatic diol, a tetra- or higher functional aliphatic polyoxycarboxylic acid, a polyhydric alcohol, A high molecular weight polyester resin having a branched structure in which a polyfunctional compound selected from a polyvalent carboxylic acid or a derivative thereof and a bifunctional aliphatic oxycarboxylic acid (for example, lactic acid, 2-hydroxybutyric acid, etc.) are used as polymerization components The manufacturing method is described. In this document, when an appropriate amount of a bifunctional aliphatic oxycarboxylic acid is used in the presence of a germanium compound, the polymerization rate is increased, and a high molecular weight polyester resin is obtained. It is also described that a branched structure can be introduced to increase the polymerization rate. In Examples of this document, 115 mol of 1,4-butanediol, 6.2 mol of 2-hydroxy-n-acetic acid in an aqueous solution in which 1% by weight of germanium oxide is dissolved with respect to 100 mol of succinic anhydride, 0.15 mol of merit acid was charged, reacted at 185 ° C. for 0.5 hour in a nitrogen atmosphere, then reacted at 220 ° C. for 0.5 hour, and further at 230 ° C. under reduced pressure of 0.5 mmHg for 3 hours. The polyester resin is obtained by reacting. However, in addition to the catalyst being limited to the germanium compound, when the ratio of the polyvalent carboxylic acid is increased, gelation may occur and the molecular weight may not be increased. In the reaction of the above example, 1,4-butanediol and the acid anhydride group of succinic anhydride or pyromellitic anhydride react predominantly, and in the reaction system, a secondary hydroxyl group having low reactivity. It is thought that 2-hydroxy-n-acetic acid having a group remains. Therefore, when this method is applied to 3-hydroxyalkanoic acid (for example, 3-hydroxybutyric acid), 3-hydroxyalkanoic acid induces an intramolecular dehydration reaction by heating to a high temperature (220 to 230 ° C.). In some cases, an unsaturated monocarboxylic acid (for example, crotonic acid) is generated and the molecular weight cannot be increased.

JP 2014-15578 A (Claims, Examples, [0012] [0014]) JP-A-9-110971 (Claims, Examples, [0009] [0010] [0032])

  Accordingly, an object of the present invention is to have a branched structure that can easily and efficiently increase the molecular weight while effectively suppressing gelation even when a hydroxyalkanoic acid having a secondary hydroxyl group is contained as a polymerization component. It is in providing the manufacturing method of polyester, and the polyester.

  Another object of the present invention is to have a branched structure that can suppress (or reduce) the intramolecular dehydration reaction and increase the molecular weight even when 3-hydroxyalkanoic acid (for example, 3-hydroxybutyric acid) is included as a polymerization component. It is in providing the manufacturing method of polyester, and the polyester.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors prepared a polyester precursor having a hydroxyl group (sometimes referred to as an OH group), and this polyester precursor was converted to a polycarboxylic acid or a reactive derivative thereof ( For example, when it is reacted with an acid anhydride or the like, gelation can be effectively suppressed, a branched structure can be efficiently formed, chain elongation can be performed to increase the molecular weight, and this method can be used to convert 3-hydroxyalkanoic acid. Even if it is contained as a polymerization component, the secondary hydroxyl group introduced into the polyester precursor and the polycarboxylic acid or its reactive derivative (particularly acid anhydride) can be easily (or efficiently) esterified. Therefore, the inventors have found that the intramolecular dehydration reaction can be suppressed (or reduced), and completed the present invention.

  That is, a step of preparing a polyester precursor having at least a polymerization component of a dicarboxylic acid or a reactive derivative thereof, a diol, and a hydroxyalkanoic acid or an alkyl ester thereof, and having a hydroxyl group, the polyester precursor, Reacting with an acid or a reactive derivative thereof to extend the chain.

  The hydroxyalkanoic acid or its alkyl ester is represented by the following formula (1):

(In the formula, group R ¹ represents an alkyl group, group R ² represents a hydrogen atom or an alkyl group, and n represents an integer of 0 to 10.)
In the formula (1), n is 1, the group R ¹ may be a C _1-4 alkyl group, and the group R ² may be a hydrogen atom or a C _1-2 alkyl group. . The polycarboxylic acid or its reactive derivative may be an acid anhydride.

  In the polyester precursor preparation step, the ratio of the diol may be an excess amount, for example, about 102 to 130 moles relative to 100 moles of the dicarboxylic acid or its reactive derivative, and the ratio of the hydroxyalkanoic acid or its alkyl ester. May be about 1 to 30 mol% with respect to the total number of moles of the whole polymerization component. The ratio of the carboxyl group or reactive derivative group of the polycarboxylic acid or its reactive derivative is 0. 1 mol per mol of the hydroxyl group of the polyester precursor, with 1 mol of acid anhydride group as 2 mol of carboxyl group. About 5-1.5 mol may be sufficient.

  In the present invention, a dicarboxylic acid or a reactive derivative thereof, a diol, a hydroxyalkanoic acid or an alkyl ester thereof is at least a polymerization component, a hydroxyl group of a polyester precursor, and a carboxyl group of a polycarboxylic acid or a reactive derivative thereof. And polyester having an ester bond and having a branched chain structure. In this polyester, the hydroxyalkanoic acid may contain 3-hydroxyalkanoic acid. Further, the polyester may have a weight average molecular weight of 7000 or more.

  In the present specification, hydroxyalkanoic acid and its alkyl ester (hydroxyl alkanoic acid alkyl) are generically called hydroxyalkanoic acids, dicarboxylic acid and its reactive derivative are called dicarboxylic acids, and polycarboxylic acid and its reactive derivatives are called as polycarboxylic acids. There is a case. The reactive derivative group is a general term for an acid anhydride group, an alkoxycarbonyl group, and an acid halide group.

  In the present invention, since the hydroxyl group of the polyester precursor and the polycarboxylic acid or a reactive derivative thereof can be efficiently esterified and chain-extended, the molecular weight can be easily and efficiently increased. Moreover, since the polyester precursor is prepared in advance, gelation can be effectively suppressed. Further, when an acid anhydride is used as the reactive derivative, esterification can be promoted and chain elongation can be effectively performed. In particular, even a polyester precursor containing 3-hydroxyalkanoic acid as a polymerization component and having a secondary hydroxyl group can be easily combined with a polycarboxylic acid or a reactive derivative thereof (especially an acid anhydride) in the chain extension step. Since it can be esterified, the molecular weight can be increased while reducing (or suppressing) the intramolecular dehydration reaction.

  The production method of the present invention comprises a step of preparing a polyester precursor having a hydroxyl group (sometimes referred to as a polyester precursor preparation step), a step of reacting this polyester precursor with a polycarboxylic acid to extend the chain ( A chain extension step).

[Preparation process of polyester precursor]
The polyester precursor includes a dicarboxylic acid or a reactive derivative thereof [for example, an acid anhydride, an alkyl ester (for example, a C _1-4 alkyl ester such as a methyl ester or an ethyl ester, an acid halide (such as an acid chloride), etc.), and a diol. And a polyester containing a hydroxyalkanoic acid or an alkyl ester thereof as a polymerization component.

(Hydroxyalkanoic acid or its alkyl ester)
The hydroxyalkanoic acid is not particularly limited as long as it has a secondary hydroxyl group, and examples thereof include hydroxyalkanoic acids represented by the following formula (1).

(In the formula, group R ¹ represents an alkyl group, group R ² represents a hydrogen atom or an alkyl group, and n represents an integer of 0 to 10.)

The group R ¹ can be selected as appropriate depending on the number of n, for example, a straight chain such as methyl, ethyl, propyl, isopropyl, butyl, s-butyl, t-butyl, hexyl, octyl, etc. Or a branched C _1-12 alkyl group, preferably a linear or branched C _1-8 alkyl group, more preferably a linear or branched C _1-6 alkyl group (for example, linear or A branched C _1-4 alkyl group). The group R ¹ is often a linear C _1-4 alkyl group (especially a methyl group).

n is an integer of 0 to 10, for example, an integer of 0 to 8 (for example, an integer of 0 to 6), preferably an integer of 1 to 4 (for example, an integer of 1 to 3, and more preferably 1 or It may be 2, especially 1. The sum of the number of n and the carbon number of R ¹ is, for example, an integer of 1 to 22 (eg, an integer of 1 to 18), preferably an integer of 2 to 13 (eg, an integer of 2 to 11), More preferably, it may be an integer of 2 to 6, particularly an integer of 2 to 4. If the sum of the number of n and the carbon number of R ¹ is too large, the biodegradability may be reduced.

Group R ² represents a hydrogen atom or an alkyl group. Examples of the alkyl group include linear or branched C _{1 1} -methyl group, ethyl group, propyl group, i-propyl group, butyl group, i-butyl group, s-butyl group, t-butyl group and the like. _It may be a ₆ alkyl group, preferably a linear or branched C _1-4 alkyl group, more preferably a methyl group or an ethyl group (particularly a methyl group).

In the formula (1), typical hydroxyalkanoic acids in which R ² is a hydrogen atom include, for example, 2-hydroxyalkanoic acids in which n is 0 [for example, 2-hydroxypropionic acid (lactic acid), 2-hydroxy 2-hydroxy C _3-14 alkanoic acid such as butanoic acid, 2-hydroxypentanoic acid, 2-hydroxyhexanoic acid, preferably 2-hydroxy C _3-9 alkanoic acid, more preferably 2-hydroxy C _3-5 alkanoic acid Etc.], 3-hydroxyalkanoic acid wherein n is 1 [for example, 3-hydroxybutanoic acid (3-hydroxybutyric acid), 3-hydroxypentanoic acid (3-hydroxyvaleric acid), 3-hydroxyhexanoic acid, 3-hydroxy 3-Heptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxynonanoic acid, 3-hydroxydecanoic acid, etc. Hydroxy C _4-15 alkanoic acid, preferably 3-hydroxy C _4-10 alkanoic acid, more preferably 3-hydroxy C _4-6 alkanoic acid], 4-hydroxyalkanoic acid wherein n is 2 (eg 4-hydroxy 4-hydroxy C _5-16 alkanoic acids such as pentanoic acid, 4-hydroxyhexanoic acid, 4-hydroxyheptanoic acid, 4-hydroxyoctanoic acid, preferably 4-hydroxy C _5-11 alkanoic acid, more preferably 4-hydroxy C _5-7 alkanoic acid), 5-hydroxyalkanoic acid wherein n is 3 (eg 5- _{hydroxyC 6-17} alkanoic acid such as 5-hydroxyhexanoic acid, 5-hydroxyheptanoic acid, preferably 5-hydroxyC _6-12 alkanoic acid, even more preferably 5-hydroxy _{C 6-8} alkanoic acids), n is 4 There 6-hydroxy acids (e.g., 6-hydroxy heptanoic acid, 6-hydroxy _{C 7-18} alkanoic acids such as 6-hydroxy-octanoic acid, preferably 6-hydroxy _{C 7-13} alkanoic acid, even more preferably 6-hydroxy C _7-9 alkanoic acid), 7-hydroxyalkanoic acids where n is 5 (eg, 7-hydroxy C _8-19 alkanoic acids such as 7-hydroxyoctanoic acid, 7-hydroxynonanoic acid, preferably 7- _{hydroxyC 8-14} alkanoic acids, more preferably 7-hydroxy C _8-10 alkanoic acids), 8-hydroxy alkanoic acids where n is 6 (e.g. 8-hydroxy C, such as 8-hydroxy nonanoic acid, 8-hydroxy decanoic acid) _9-20 alkanoic acids, preferably 8-hydroxy C _9-15 alkanoic acids, more preferably 8-hydroxy C _9-11 alkanoic acid), 9-hydroxy alkanoic acids where n is 7 (eg 9-hydroxy C _10-21 alkanoic acids such as 9-hydroxydecanoic acid, 9-hydroxyundecanoic acid, preferably 9 _-Hydroxy C _10-16 alkanoic acid, more preferably 9-hydroxy C _10-12 alkanoic acid), 10-hydroxy alkanoic acid wherein n is 8 (eg 10-hydroxyundecanoic acid, 10-hydroxydodecanoic acid etc. 10 _-Hydroxy C _11-22 alkanoic acid, preferably 10-hydroxy C _11-17 alkanoic acid, more preferably 10-hydroxy C _11-13 alkanoic acid and the like, 11-hydroxyalkanoic acid wherein n is 9 (eg 11 - such as hydroxy dodecanoic acid 11-hydroxy _{C 12-23} alkanes , 12 preferably 11-hydroxy _{C 12-18} alkanoic acid, even more preferably such 10-hydroxy _{C 12-14} alkanoic acids), n is such as is 10 12-hydroxy alkanoic acids (e.g., 12-hydroxy tridecane acid _-Hydroxy C _13-24 alkanoic acid, preferably 12-hydroxy C _13-19 alkanoic acid, more preferably 12-hydroxy C _13-15 alkanoic acid and the like.

In the formula (1), examples of the hydroxyalkanoic acids in which R ² is an alkyl group include alkyl esters of the hydroxyalkanoic acids exemplified above (for example, C _1-6 alkyl esters, preferably C _1-4 alkyl esters, More preferred examples include a methyl group, an ethyl group, and particularly a methyl group. These hydroxyalkanoic acids can be used alone or in combination of two or more. Among these hydroxyalkanoic acids, 3-hydroxyalkanoic acids where n is 1 (for example, 3-hydroxyC _4-10 alkanoic acids such as 3-hydroxybutyric acid, 3-hydroxyvaleric acid, 3-hydroxyhexanoic acid, these C _1-2 alkyl ester of 3-hydroxyalkanoic acid, and the like, 4-hydroxyalkanoic acid wherein n is 2 (4-hydroxyCanoic acid such as 4-hydroxypentanoic acid, 4-hydroxyhexanoic acid, 4-hydroxyheptanoic acid) _5-11 alkanoic acids, C _1-2 alkyl esters of these 4-hydroxyalkanoic acids, etc.) are preferred. The hydroxyalkanoic acid may be an optical isomer (R-form or S-form) or a racemate. In addition, a commercially available product may be used as the hydroxyalkanoic acid (hydroxyalkanoic acid alkyl) in which R ² is an alkyl group, and a conventional esterification method [for example, an alcohol corresponding to hydroxyalkanoic acid and R ² (for example, methanol Or a C _1-4 alkanol such as ethanol). In particular, 3-hydroxyalkanoic acids in which n is 1 can be preferably used. In addition, since the alkyl ester of 3-hydroxyalkanoic acid may reduce the elimination of hydrogen at the α-position of the carbonyl group due to alkyl esterification, the unsaturated monocarboxylic acid (or unsaturated monocarboxylic acid alkyl) Generation may be effectively suppressed.

(Dicarboxylic acid and its reactive derivatives)
Examples of dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, and reactive derivatives thereof [for example, alkyl esters ( _C1-4 alkyl esters, etc.), acid halides (acid chlorides, etc.). , Acid anhydrides, etc.].

Examples of the aliphatic dicarboxylic acid include alkane dicarboxylic acids (eg, C _2-16 alkane dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, etc.) And unsaturated aliphatic dicarboxylic acids (for example, C _2-10 alkene-dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid).

Examples of the alicyclic dicarboxylic acid include cycloalkane dicarboxylic acid (for example, C _5-10 cycloalkane dicarboxylic acid such as 1.4-cyclohexanedicarboxylic acid), di- or tricycloalkane dicarboxylic acid (for example, decalin dicarboxylic acid). , Norbornane dicarboxylic acid, adamantane dicarboxylic acid, tricyclodecane dicarboxylic acid, etc.), cycloalkene dicarboxylic acid (eg C _5-10 cycloalkene-dicarboxylic acid such as cyclohexene dicarboxylic acid), di- or tricycloalkene dicarboxylic acid (eg, Norbornene dicarboxylic acid and the like).

Examples of the aromatic dicarboxylic acid include monocyclic aromatic dicarboxylic acids [for example, phthalic acid, terephthalic acid, isophthalic acid, alkylisophthalic acid (for example, C _1-4 alkylisophthalic acid such as 4-methylisophthalic acid, etc.) C _6-10 arene dicarboxylic acid and the like], polycyclic aromatic dicarboxylic acid [for example, condensed polycyclic aromatic dicarboxylic acid [for example, naphthalenedicarboxylic acid (for example, 1,5-naphthalenedicarboxylic acid, 1,6 -Naphthalenedicarboxylic acid having two carboxyl groups in different rings such as naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid; 1,2-naphthalenedicarboxylic acid , 1,4-naphthalenedicarboxylic acid, etc. Naphthalenedicarboxylic acid having a sill group), anthracene dicarboxylic acid, phenanthrene fused polycyclic C _10-24 arene carboxylic acids, such as - dicarboxylic acid, preferably fused polycyclic C _10-16 arene - dicarboxylic acid, more preferably Condensed polycyclic C _10-14 arene-dicarboxylic acid and the like], arylarene dicarboxylic acid [for example, biphenyl dicarboxylic acid (for example, 2,2′-biphenyl dicarboxylic acid, 4,4′-biphenyl dicarboxylic acid, etc.) _6-10 aryl-C _6-10 arene-dicarboxylic acids and the like], diarylalkane dicarboxylic acids [for example, diC _6-10 aryl C ₁ such as diphenylalkanedicarboxylic acid (for example, 4,4′-diphenylmethanedicarboxylic acid, etc.) _-6 alkane-dicarboxylic acid etc.], di Aryl ketone dicarboxylic acids [for example, diC _6-10 aryl ketone-dicarboxylic acids such as diphenyl ketone dicarboxylic acid (for example, 4.4′-diphenyl ketone dicarboxylic acid)], dicarboxylic acids having a fluorene skeleton, etc. Is mentioned. These dicarboxylic acids can be used alone or in combination of two or more.

Examples of the dicarboxylic acid having a fluorene skeleton include dicarboxyfluorene (eg, 2,7-dicarboxyfluorene); 9,9-bis (carboxyalkyl) fluorene [eg, 9,9-bis (2-carboxyethyl). ) Fluorene, 9,9-bis (carboxyC _2-6 alkyl) fluorene, such as 9,9-bis (2-carboxypropyl) fluorene]; 9- (carboxy-carboxyalkyl) fluorene [eg 9- (1 -Carboxy-2-carboxyethyl) fluorene, 9- (carboxy-carboxy C _2-6 alkyl) fluorene such as 9- (2-carboxy-3-carboxypropyl) fluorene, etc.]; 9,9-bis (carboxyaryl) Fluorene [eg, 9,9-bis (3-carboxyphene E) fluorene, 9,9-bis (4-carboxyphenyl) fluorene, 9,9-bis (5-carboxy-1-naphthyl) fluorene, 9,9-bis (6-carboxy-2-naphthyl) fluorene, etc. 9,9-bis (carboxyC _6-12 aryl) fluorene and the like]; 9,9-bis (carboxyalkyl-aryl) fluorene [eg, 9,9-bis (4- (carboxymethyl) phenyl) fluorene, 9-bis (4- (2-carboxyethyl) phenyl) fluorene, 9,9-bis (3- (carboxymethyl) phenyl) fluorene, 9,9-bis (5- (carboxymethyl) -1-naphthyl) fluorene , 9,9-bis (6- (carboxymethyl) -2-naphthyl) fluorene such as 9,9-bis (carboxy _{C 1-6} Al Le _{-C 6-12} aryl) fluorene], and others.

Among these dicarboxylic acids, aliphatic dicarboxylic acids (C _2-6 alkanedicarboxylic acids such as succinic acid and adipic acid) from the viewpoint of biodegradability, alicyclic dicarboxylic acids, aromatics from the viewpoint of heat resistance, etc. Group dicarboxylic acids. In particular, when an acid anhydride (for example, succinic anhydride) is used, the molecular weight of the polyester precursor can often be increased.

(Diol)
Examples of the diol include aliphatic diols, alicyclic diols, and aromatic diols.

Examples of the aliphatic diol include alkanediol (ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1 , 3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, neopentylglycol and other C _2-10 alkane diols, preferably C _2-6 alkane diols, more preferably C _2-4 alkane diols ), Polyalkane diols (for example, di- or tri-C _2-4 alkane diols such as diethylene glycol, dipropylene glycol, and triethylene glycol).

Examples of the alicyclic diol include cycloalkanediol (for example, C _5-8 cycloalkanediol such as cyclohexanediol) and di (hydroxyalkyl) cycloalkane (for example, di (hydroxyC _1-4 ) such as cyclohexanedimethanol. Alkyl) C _5-8 cycloalkane, etc.), isosorbide and the like.

Examples of the aromatic diol include dihydroxyarenes (for example, hydroquinone and resorcinol) and di (hydroxyalkyl) arenes (for example, di (hydroxyC ₁ ) such as 1,3-benzenedimethanol and 1,4-benzenedimethanol. _-4 alkyl) C _6-10 arene, etc.), bisphenols (eg, bis (hydroxyphenyl) C _1-10 alkanes such as biphenol, bisphenol A, etc.), alkylene oxide adducts of bisphenols, diols having a fluorene skeleton, etc. Is mentioned. These diols can be used alone or in combination of two or more.

  Examples of the diol having a fluorene skeleton include diol compounds having a 9,9-bis (hydroxyaryl) fluorene skeleton, such as a diol represented by the following formula (2).

(In the formula, ring Z represents an arene ring, R ³ represents an alkylene group, R ⁴ and R ⁵ represent a substituent, p represents an integer of 0 or 1 or more, k represents an integer of 0 to 4, and m represents 0 or 1) (It is an integer above.)

In the formula (2), examples of the arene ring represented by the ring Z include a monocyclic arene ring such as a benzene ring, a polycyclic arene ring, and the like. The polycyclic arene ring includes a condensed polycyclic arene. ring [e.g., fused bicyclic arene (e.g., fused bicyclic C _10-16 arene such as naphthalene ring), such as fused bicyclic or tetracyclic arene ring such as ring, ring assembly arene ring [Biaren ring (e.g., BiC _6-12 arene rings such as biphenyl ring and binaphthyl ring] and the like. The two rings Z may be the same or different rings. Preferred arene rings include benzene ring, naphthalene ring, biphenyl ring and the like.

In the formula (2), examples of the alkylene group R ³ include C _2-6 alkylene groups such as an ethylene group, a propylene group, a trimethylene group, and a 1,2-butanediyl group. In addition, when m is an integer greater than or equal to ² , the kind of alkylene group R3 may be the same or different. Further, the type of the alkylene group R ³ may be the same or different in the same or different ring Z.

The number m of the oxyalkylene group (OR ³ ) can be selected, for example, from a range of about an integer of 0 to 15 (eg, an integer of 0 to 10), for example, an integer of 0 to 8 (eg, 1 to 8), Preferably, it may be an integer of 0 to 4 (for example, 1 to 4), particularly an integer of about 0 to 3 (for example, 1 to 3), and is usually an integer of 0 to 2 (for example, 0 or 1). There may be.

The group [HO— (R ³ O) _m —] can be substituted at an appropriate position of the ring Z. For example, when the ring Z is a benzene ring, the 2-4 position (especially 3- In many cases, when ring Z is a naphthalene ring, it is often substituted at the 5- to 8-position of the naphthyl group, for example, the 9-position of fluorene. Is substituted at the 1-position or 2-position of the naphthalene ring (substitution is made in relation to 1-naphthyl or 2-naphthyl), and the 1,5-position, 2,6-position, etc. with respect to this substitution position In many cases, the group [HO— (R ³ O) _m —] is substituted. In the ring assembly arene ring Z, the substitution position of the group [HO— (R ³ O) _m —] is not particularly limited. For example, the arene ring bonded to the 9-position of fluorene and / or this arene ring It may be substituted on the adjacent arene ring. For example, the 3-position or 4-position of the biphenyl ring Z may be bonded to the 9-position of fluorene, and when the 4-position of the biphenyl ring Z is bonded to the 9-position of fluorene, the group [HO The substitution position of — (R ³ O) _m —] may be any of 2-, 3-, 2′-, 3′-, and 4′-positions, and is usually 2-, 3′-, 4 It may be substituted at the '-position, preferably the 2-, 4'-position (particularly the 2-position).

In the formula (2), examples of the substituent R ⁴ include an alkyl group (eg, a C _1-6 alkyl group such as a methyl group, an ethyl group, and a propyl group), a cycloalkyl group (such as a cyclohexyl group), and the like. C _5-8 cycloalkyl group, etc.), aryl groups (eg, C _6-10 aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group, etc.), aralkyl groups (C _6-6 such as benzyl group, phenethyl group, etc.) ₁₀ an aryl _{-C 1-4} alkyl group) carbon atoms and the like; alkoxy group (methoxy group, a _{C 1-6} alkoxy group such as ethoxy group), _C of such cycloalkyl group (hexyloxy group cycloheteroalkyl _{5- 8} such cycloalkyloxy group), _{C 6-10} aryloxy groups such as an aryloxy group (phenoxy group), aralkyloxy group (benzyl Such as _{C 1-8} alkylthio group such as an alkylthio group (methylthio group);; _{C 6-10} aryl _{-C 1-4} alkyl group), such as oxy _{C 1-6} alkyl, such as acyl groups (acetyl group - carbonyl group Alkyloxycarbonyl group (C _1-4 alkyloxy-carbonyl group such as methoxycarbonyl group); halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom etc.); nitro group; cyano group; dialkylamino group (e.g., di-C _1-4 alkylamino group such as dimethylamino group); dialkyl carbonyl amino group (e.g., di-C _1-4 alkyl, such as di-acetylamino group - carbonyl amino group), and others.

Representative substituents R ⁴ include C _1-6 alkyl groups (particularly methyl groups), C _6-10 aryl groups (particularly phenyl groups), C _6-8 aryl-C _1-2 alkyl groups, C _{1- 4} alkoxy group etc. are mentioned. In addition, when the substituent R ⁴ is an aryl group, the substituent R ⁴ may form the ring assembly arene ring together with the ring Z. The type of the substituent R ⁴ may be the same or different in the same or different ring Z.

The number p of substitutions can be appropriately selected according to the type of ring Z and the like, and may be an integer of about 0 to 8, for example, an integer of 0 to 4, preferably 0 to 3 (for example, 0 to 2). It may be an integer, especially 0 or 1. In particular, when p is 1, the ring Z may be a benzene ring, a naphthalene ring or a biphenyl ring, and the substituent R ⁴ may be a methyl group.

Examples of the substituent R ⁵ include a cyano group, a halogen atom (fluorine atom, chlorine atom, bromine atom, etc.), carboxyl group, alkyl group (C _1-6 alkyl group such as methyl group, ethyl group, propyl group), An aryl group (C _6-10 aryl group such as a phenyl group) and the like can be mentioned. The substituent R ⁵ is often an alkyl group (for example, a C _1-4 alkyl group, particularly a C _1-3 alkyl group such as a methyl group). The substitution number k is an integer of 0 to 4 (for example, 0 to 3), preferably an integer of 0 to 2 (for example, 0 or 1), particularly 0. The number of substitutions k may be the same or different from each other. When k is 2 or more, the types of the substituents R ⁵ may be the same or different from each other, and are substituted with two benzene rings of the fluorene ring. The type of the substituent R ⁵ may be the same or different. Further, the substitution position of the substituent R ⁵ is not particularly limited, and may be, for example, 2-position to 7-position (2-position, 3-position and / or 7-position, etc.) of the fluorene ring.

In the formula (2), examples of the compound in which m is 0 include 9,9-bis (hydroxyaryl) fluorenes {for example, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3 9,9-bis (hydroxyC _6-12 ) such as -hydroxyphenyl) fluorene, 9,9-bis (6-hydroxy-2-naphthyl) fluorene, 9,9-bis (5-hydroxy-1-naphthyl) fluorene 9,9-bis (C _6-12 aryl) such as aryl) fluorene, 9,9-bis (3-phenyl-4-hydroxyphenyl) fluorene, 9,9-bis (4-phenyl-3-hydroxyphenyl) fluorene - hydroxy _{C 6-12} aryl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, 9,9-bis (4 Methyl-3-hydroxyphenyl) fluorene such as 9,9-bis _{(C 1-4} alkyl - hydroxy _{C 6-12} aryl) fluorene, and others.

In the formula (2), the compound in which m is 1 includes 9,9-bis (hydroxyalkoxyaryl) fluorenes {for example, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene, 9 , 9-bis [4- (2-hydroxypropoxy) phenyl] fluorene, 9,9-bis [6- (2-hydroxyethoxy) -2-naphthyl] fluorene, 9,9-bis [5- (2-hydroxy) propoxy) -1-naphthyl] 9,9-bis fluorene (hydroxy _{C 2-4} alkoxy _{C 6-12} aryl) fluorene, 9,9-bis [4-phenyl-3- (2-hydroxyethoxy) phenyl] fluorene, 9,9-bis [3-phenyl-4- (2-hydroxypropoxy) phenyl] fluorene such as 9,9-bis _{[C 6-12} Reel - hydroxy _{C 2-4} alkoxy _{C 6-12} aryl] fluorene, 9,9-bis [3-methyl-4- (2-hydroxyethoxy) phenyl] fluorene, 9,9-bis [4-methyl-3- Examples include 9,9-bis [C _1-4 alkyl-hydroxy C _2-4 alkoxy C _6-12 aryl] fluorene, etc.] such as (2-hydroxypropoxy) phenyl] fluorene.

In the formula (2), the compound in which m is 2 or more corresponds to the compound in which m is 0 or 1, and the repeating unit m of an oxyalkylene group (particularly an oxyC _2-4 alkylene group) is 2 to 5 Compound etc. are mentioned.

  Of these diols, from the viewpoint of biodegradability, aliphatic diols (for example, alkane diols such as ethylene glycol and 1,4-butanediol), from the viewpoint of heat resistance, alicyclic diols, aromatic diols, etc. Is mentioned.

In addition, as a polymerization component, other components, for example, hydroxycarboxylic acid (for example, hydroxyalkanoic acid having primary or tertiary hydroxyl group, hydroxycyclohexanecarboxylic acid, hydroxybenzoic acid, etc.), ester-forming derivatives thereof [ For example, lower alkyl esters (such as C _1-4 alkyl esters), acid halides (such as acid chloride)], lactones, and the like may be used.

Examples of the hydroxyalkanoic acid having a primary hydroxyl group include glycolic acid, 3-hydroxypropanoic acid, 4-hydroxybutanoic acid, 5-hydroxypentanoic acid, 6-hydroxyhexanoic acid, 7-hydroxypentanoic acid, 8- Hydroxyoctanoic acid, 9-hydroxynanoic acid, hydroxy C _2-15 alkanoic acid such as 10-hydroxydecanoic acid) and the like. Examples of hydroxyalkanoic acids having a tertiary hydroxy group include 2-hydroxy- 2-methyl-pentanoic acid, 3-hydroxy-3-methyl-butanoic acid, 4-hydroxy-4-methyl-butanoic acid, 5-hydroxy-5-methyl-pentanoic acid, 6-hydroxy-6-methyl-hexanoic acid etc. are exemplified hydroxy _{C 3-15} alkanoic acid - _{C 1-6} alkyl such as That.

As the lactone, a lactone corresponding to the hydroxyalkanoic acid having the primary hydroxy group (for example, C _3-15 lactone such as β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, etc.), Examples thereof include lactones corresponding to the hydroxyalkanoic acid having a tertiary hydroxy group (for example, di-C _1-12 alkyl-C _3-15 lactone such as β-dimethylpropiolactone and γ-dimethylbutyrolactone). These other components can be used alone or in combination of two or more.

  In the method of the present invention, a diol or a hydroxyalkanoic acid (particularly hydroxyalkanoic acid) unit is introduced at the terminal, so that the ratio of the diol is an excess mole relative to the dicarboxylic acid, for example, 100 moles of the dicarboxylic acid. It may be about 102 to 130 mol, preferably about 105 to 120 mol (for example, 105 to 110 mol).

  The proportion of the hydroxyalkanoic acid can be appropriately selected according to the introduction ratio of the hydroxyalkanoic acid unit to the polyester precursor, and is, for example, 1 to 30 mol% (for example, 2 to 15) with respect to the total number of moles of the entire polymerization component. Mol%), preferably 3 to 10 mol%, more preferably about 4 to 7 mol% (for example, 4 to 6 mol%). When 3-hydroxyalkanoic acids are used, an intramolecular dehydration reaction may occur. Therefore, if the proportion of 3-hydroxyalkanoic acids is too large, the molecular weight may decrease.

  The OH group of the polyester precursor may be a primary OH group derived from a diol or a secondary OH group derived from hydroxyl alkanoic acid, but usually a hydroxyalkanoic acid having low reactivity. Since it can be presumed that the derived secondary OH group is introduced at the terminal, it is often a secondary OH group.

  The polyester precursor can be produced by condensation polymerization of the polymerization components. Examples of the polymerization method (manufacturing method) include conventional methods such as a melt polymerization method (a method of polymerizing diol and dicarboxylic acid under melt mixing), a solution polymerization method, an interfacial polymerization method, and the like.

  In addition, the dicarboxylic acid [dicarboxylic acid anhydride (for example, succinic anhydride, maleic anhydride, etc.)] is reacted with hydroxyalkanoic acid to prepare dicarboxylic acid having a skeleton derived from 3-hydroxyalkanoic acid ( Alternatively, a reactive derivative thereof may be prepared and the dicarboxylic acid (or reactive derivative thereof) may be subjected to a polymerization reaction. In the form of such a dicarboxylic acid (or a reactive derivative thereof), since the secondary OH group is esterified, even if it is a 3-hydroxyalkanoic acid (for example, 3-hydroxybutyric acid), Since unsaturated monocarboxylic acid (particularly α, β-unsaturated carboxylic acid) is not generated by intramolecular dehydration, a skeleton derived from 3-hydroxyalkanoic acid can be efficiently introduced into the polyester precursor and the molecular weight can be improved.

  In the method of the present invention, no catalyst may be used, and the catalyst is not limited to a specific catalyst, and a conventional catalyst may be used. Examples of the catalyst include metal catalysts [for example, alkali metals (sodium, etc.), alkaline earth metals (magnesium, calcium, barium, etc.), transition metals (manganese, zinc, cadmium, lead, cobalt, titanium, etc.), periodic table Group 13 metals (such as aluminum), periodic table group 14 metals (germanium, tin, etc.), periodic table Group 15 metals (such as antimony), etc.], base catalysts (eg, tertiary amines) (Trialkylamines such as trimethylamine and triethylamine, quaternary ammonium salts (tetraalkylammonium halides such as tetraethylammonium chloride and tetraethylammonium bromide, benzyltrialkylammonium halides such as benzyltrimethylammonium chloride), etc.), acid catalyst For example, inorganic acids (for example, sulfuric acid, hydrogen chloride (or hydrochloric acid), nitric acid, phosphoric acid, etc.), organic acids (for example, sulfonic acids (alkanesulfonic acids such as methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, p -Arene sulfonic acids such as toluene sulfonic acid) etc.] etc. Examples of metal compounds include organic acid salts (acetate, propionate, etc.), inorganic acid salts (borate, carbonate, etc.). ), Metal oxides (such as germanium oxide), metal chlorides (such as tin chloride), metal alkoxides (such as titanium tetraalkoxide, titanium tetra-butoxide, aluminum isopropoxide, zinc t-butoxide, potassium t-butoxide), Examples include alkyl metals (such as trialkylaluminum), etc. These catalysts are simple. Or it can be used in combination of two or more.

The amount of the catalyst used is, for example, about 0.01 × 10 ^{−4 to} 100 × 10 ⁻⁴ mol, preferably about 0.1 × 10 ⁻⁴ to 40 × 10 ⁻⁴ mol, relative to 1 mol of dicarboxylic acids. May be.

The reaction may be performed in the presence or absence of a solvent depending on the polymerization method. Examples of the solvent include hydrocarbons (aliphatic hydrocarbons such as hexane, octane and cyclohexane, aromatic hydrocarbons such as toluene), halogenated hydrocarbons (dichloromethane, chloroform, carbon tetrachloride, etc.), ether (Cyclic ethers such as dioxane and tetrahydrofuran), ketones (acetone, methyl ethyl ketone, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), amides (dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, etc.) ), Sulfoxides (such as dimethyl sulfoxide), cellosolve acetates (such as _C1-4 alkyl cellosolve acetate such as ethyl cellosolve acetate), and the like. These solvents can be used alone or in combination of two or more.

  The reaction can usually be performed in an inert gas (nitrogen, helium, etc.) atmosphere. In addition, the reaction may be performed at room temperature or under reduced pressure, and may be performed while distilling generated water or the like out of the reaction system.

  The reaction temperature may be, for example, 70 to 250 ° C. (for example, 120 to 220 ° C.), preferably about 150 to 200 ° C. In particular, when 3-hydroxyalkanoic acids are used, an intramolecular dehydration reaction occurs, and an unsaturated monocarboxylic acid (or an unsaturated monocarboxylic acid alkyl) may be generated. Therefore, the reaction temperature is relatively low, for example, 50 It may be about -190 ° C, preferably about 100-185 ° C (for example, 130-180 ° C). The reaction time is not particularly limited, and may be, for example, 30 minutes to 48 hours, usually about 1 to 36 hours. In many cases, alkyl esters of hydroxyalkanoic acid can be polymerized even at low temperatures.

  In addition, after completion | finish of reaction, although a polyester precursor may be isolate | separated and refined by a conventional method, it is usually used for a chain | strand extension process, without carrying out isolation | separation purification.

(Polyester precursor)
When measured by gel permeation chromatography (GPC), the weight average molecular weight (Mw) of the polyester precursor is, for example, 1000 to 70000 (for example, 2000 to 50000), preferably 3000 to 30000, more preferably 4000 in terms of polystyrene. About 20,000 (for example, 5,000 to 10,000) may be sufficient. Moreover, molecular weight distribution (Mw / Mn, Mn shows a number average molecular weight) is 1.2-3.5, for example, Preferably it is 1.4-3.0, More preferably, it is 1.6-2.5 ( For example, it may be about 1.8 to 2.2).

(Chain extension process)
In the chain extension step, by reacting the polyester precursor with a polycarboxylic acid or a reactive derivative thereof, the hydroxyl group of the polyester precursor and the carboxyl group (or reactive derivative group) of the polycarboxylic acid are ester-bonded. Can be efficiently chain-extended. In this chain extension process, since it reacts with polycarboxylic acids in the form of a polyester precursor, a branched structure can be efficiently formed while suppressing gelation.

  The polycarboxylic acids need only have three or more carboxyl groups (or reactive derivative groups thereof) in one molecule, and the number of carboxyl groups (or reactive derivative groups thereof) is, for example, 3 to 8, Preferably 3-6 (for example, 3-5), More preferably, 3 or 4 may be sufficient. If the number of carboxyl groups (or reactive derivative groups thereof) is too large, the polyester may be gelled.

The polycarboxylic acids may have a substituent. Examples of the substituent include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl group (eg, C _1-6 alkyl group such as methyl group, ethyl group, propyl group, etc.), hydroxyl group, etc. , Alkoxy groups (C _1-6 alkoxy groups such as methoxy group and ethoxy group), nitro groups, cyano groups, dialkylamino groups (for example, di-C _1-4 alkylamino groups such as dimethylamino group) and the like it can. A substituent can be used individually or in combination of 2 or more types.

  Examples of the polycarboxylic acid include aliphatic polycarboxylic acid, alicyclic polycarboxylic acid, and aromatic polycarboxylic acid.

Examples of the aliphatic polycarboxylic acid include 1,2,3-propanetricarboxylic acid, propene-1,2,3-tricarboxylic acid, 2-methylpropanetricarboxylic acid, 1,3,5-pentanetricarboxylic acid, Examples thereof include C _3-10 alkanes such as 2,3,4-butanetetracarboxylic acid or alkene-tri to hexacarboxylic acid, preferably C _3-6 alkanes, alkene-tri or tetracarboxylic acids.

Examples of the alicyclic polycarboxylic acid include 1,3,5-cyclohexanetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3, C _4-10 cycloalkane such as 4-cyclopentanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 1,2,3,4,5,6-cyclohexanehexacarboxylic acid or alkene-tri to Examples thereof include hexacarboxylic acid, C _4-8 cycloalkane, alkene-tri, and tetracarboxylic acid.

Examples of the aromatic polycarboxylic acid include 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,3,5-benzenetricarboxylic acid, 1,2,4. , 5-benzene tetracarboxylic acid (pyromellitic acid), 1,4,5,8-naphthalene tetracarboxylic acid, 3,3 ', _{C 6-12} arene such as 4,4'-biphenyltetracarboxylic acid - tri or Examples include hexacarboxylic acid, preferably C _6-10 arene-tri or tetracarboxylic acid. These polycarboxylic acids can be used alone or in combination of two or more.

  Examples of the reactive derivative of polycarboxylic acid include acid anhydrides, alkyl esters and acid halides formed from the polycarboxylic acid.

  Examples of the acid anhydride include aliphatic carboxylic acid anhydrides, alicyclic carboxylic acid anhydrides, and aromatic carboxylic acid anhydrides.

Examples of the aliphatic carboxylic acid anhydride include C _3-10 alkanes such as butane-1,2,3,4-tetracarboxylic dianhydride and ethylenetetracarboxylic dianhydride, or alkene-tri to hexacarboxylic acid. Examples thereof include mono- to trianhydrides, C _3-6 alkanes, alkene-tri, or tetracarboxylic acid mono- or dianhydrides.

Examples of the alicyclic carboxylic acid anhydride include 1,2,4-cyclohexanetricarboxylic acid-1,2-anhydride, methylcyclohexene carboxylic acid anhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride. 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4,5,6-cyclohexanehexacarboxylic Examples thereof include C _4-10 cycloalkanes such as acid dianhydrides or alkene-tri to hexacarboxylic acid mono- to _{trianhydrides} , C _4-8 cycloalkane-tri or tetracarboxylic acid mono- or dianhydrides, and the like.

Examples of the aromatic carboxylic acid anhydride include 1,2,4-benzenetricarboxylic acid-1,2-anhydride (trimellitic acid), 1,2,4,5-benzenetetracarboxylic dianhydride (anhydrous). pyromellitic acid), 1,4,5,8-naphthalene tetracarboxylic dianhydride, 3,3 ', _{C 6-12} arene such as 4,4'-biphenyltetracarboxylic dianhydride - tri to hexa-carboxylic Examples thereof include acid mono-trianhydrides, preferably C _6-10 arene-tri or tetracarboxylic acid mono- or dianhydrides. These acid anhydrides can be used alone or in combination of two or more.

Examples of the alkyl ester include linear or branched C _{1 1} -methyl ester, ethyl ester, propyl ester, i-propyl ester, butyl ester, i-butyl ester, s-butyl ester, t-butyl ester and the like. _4- alkyl esters, especially methyl esters, ethyl esters and the like.

  Examples of the acid halide include acid chloride, acid bromide, and acid iodide.

  Of these polycarboxylic acids, aliphatic polycarboxylic acids are preferred from the viewpoint of biodegradability. Of these polycarboxylic acids, tri- or tetracarboxylic acid (or a reactive derivative thereof) is preferable from the viewpoint of suppressing gelation. In particular, when an acid anhydride (for example, trimellitic acid, pyromellitic acid, etc.) is used, the reactivity between the acid anhydride group and the hydroxyl group of the polyester precursor is high, and the chain can be efficiently extended in many cases.

  The ratio of the carboxyl group (or reactive derivative group) of the polycarboxylic acid (or reactive derivative thereof) is, for example, 0.5 to 1.5 mol, preferably 1 mol relative to 1 mol of the hydroxyl group of the polyester precursor. It may be about 0.7 to 1.3 mol (for example, 0.8 to 1.2 mol), more preferably about 0.9 to 1.1 mol (particularly 0.9 to 1.0) mol. . In addition, an acid anhydride group can be calculated as 1 mol of an acid anhydride group as 2 mol of a carboxyl group.

  The reaction may be performed in the absence of a catalyst or in the presence of a catalyst. Examples of the catalyst include the above-exemplified acid catalysts, base catalysts, metal alkoxides, and the like, and an acid catalyst can be suitably used.

  The ratio of the catalyst is 0.001 to 2 mol%, preferably 0.01 to 1 mol%, more preferably 0.1 to 0.5 mol% with respect to the carboxyl group (or reactive derivative group) of the polycarboxylic acid. It may be about mol%.

  In addition, when using the said acid halide, in order to trap the hydrogen halide produced by reaction, you may carry out in presence of a base. Examples of the base include metal hydroxides (alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide) and metal carbonates (sodium carbonate and hydrogen carbonate). Inorganic bases such as alkali metal carbonates or alkaline earth metal salts such as sodium), amines (trialkylamines such as triethylamine, aromatic tertiary amines such as benzyldimethylamine, heterocyclic tertiary such as pyridine) And organic bases such as amine).

  Although the usage-amount of a base is not specifically limited, For example, it is 0.1-20 mol with respect to 1 mol of said hydroxy alkanoic acid (hydroxyl group), Preferably it is 1-10 mol (for example, 1.5- It may be about 5 mol).

  The reaction may be performed with stirring in air or in an inert atmosphere (nitrogen, rare gas, etc.), and may be performed under normal pressure, under pressure, or under reduced pressure. Furthermore, the reaction may be carried out in the presence or absence of a solvent. As the solvent, for example, the same solvent as described above can be used.

  The reaction temperature may be, for example, about 100 to 250 ° C, preferably about 150 to 230 ° C, and more preferably about 180 to 220 ° C. When reaction temperature is too high, there exists a possibility that the introduction amount (or introduction ratio) of the 3-hydroxyalkanoic acid unit with respect to polyester may fall. The reaction time is not particularly limited, and may be, for example, 30 minutes to 48 hours, usually 1 to 36 hours, preferably about 2 to 24 hours. Even if a 3-hydroxyalkanoic acid unit is introduced at the terminal of the polyester precursor to be subjected to the reaction, it is esterified, so even in the presence of a catalyst (for example, an acid catalyst), hydrogen at the α-position of the carbonyl group In some cases, the detachability of the resin can be reduced.

Further, after completion of the reaction, the polyester can be separated by a conventional separation method, for example, a method of reprecipitation of the reaction product with a poor solvent (for example, low solubility of high molecular weight polyester and solubility of unreacted components and low molecular weight polyester). May be separated and purified by a method such as fractionation with a high solvent. Examples of the poor solvent include aqueous solvents [e.g., water, alcohols (e.g., _C1-4 alkanols such as methanol, ethanol, isopropanol), etc.], hydrocarbons (e.g., hexane, etc.), and the like.

  As described above, in the method of the present invention, the polymerization component is not added simultaneously, but has a polyester precursor preparation step and a chain extension step. Gelation due to formation can be effectively suppressed, and chain elongation can be efficiently performed. Therefore, the molecular weight (average molecular weight) of the polyester can be increased.

  In the method of the present invention, the molecular weight can be increased even if 3-hydroxyalkanoic acid is included in the polymerization component. That is, when a polycarboxylic acid or a reactive derivative thereof (especially an acid anhydride) is used, chain elongation can be efficiently achieved by esterification of the secondary hydroxyl group of the polyester precursor, and the content of 3-hydroxyalkanoic acid unit A high polyester can be obtained.

(polyester)
In the polyester of the present invention, the hydroxyl group of the polyester precursor (particularly the secondary OH group derived from hydroxyalkanoic acid) and the carboxyl group (or reactive derivative group) of the polycarboxylic acid or its reactive derivative are esters. It forms a bond and has a branched chain structure. That is, it has a polyester precursor unit and a polycarboxylic acid unit.

  In particular, a polyester having, as a constituent unit, a polyester precursor containing an aliphatic dicarboxylic acid, an aliphatic diol, and a hydroxyalkanoic acid as a polymerization component is excellent in biodegradability and useful as a biodegradable plastic. In addition, since the polyester is obtained by chain elongation in the form of a polyester precursor, it has a branched structure, but it can be estimated that there are relatively few crosslinking points, which is advantageous for biodegradation.

  The ratio of the hydroxyalkanoic acid unit of the polyester is, for example, 1 mol% or more (for example, 2 to 15 mol%), preferably 3 mol% or more (3 to 10 mol%) with respect to the total number of moles of the polymerization components. For example, 5 mol% or more (for example, 7 to 25 mol%), preferably 10 mol% or more (for example, 15 to 20 mol%). If the proportion of hydroxyalkanoic acid is too small, biodegradability may be reduced.

  The polyester has a relatively high molecular weight even if it contains a skeleton derived from 3-hydroxyalkanoic acid (particularly 3-hydroxybutyric acid) that is difficult to chemically polymerize. When the weight average molecular weight (Mw) of this polyester is measured by gel permeation chromatography (GPC), it is 7000 or more (for example, 7000 to 100,000), preferably 8000 or more (for example, 8000 to 70000) in terms of polystyrene. For example, it may be about 10,000 or more (for example, 10,000 to 60,000), preferably about 15,000 or more (for example, 20,000 to 50,000). Moreover, molecular weight distribution (Mw / Mn, Mn shows a number average molecular weight) is 1.2-3.5, for example, Preferably it is 1.4-3.0, More preferably, it is 1.6-2.5 ( For example, it may be about 1.8 to 2.2).

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

(Molecular weight)
The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured by gel permeation chromatography (manufactured by TOSOH, “HLC-8320GPC”), dissolved in chloroform, and measured in terms of polystyrene.

Example 1
Succinic acid 35.4 g (0.300 mol), 1,4-butanediol 28.4 g (0.315 mol), (R) -3-hydroxybutyric acid 3 g (0.029 mol), germanium dioxide (GeO ₂ ) 0.3 g Was placed in a 200 ml flask and reacted at 180 ° C. for 1 hour. Then, after reacting under reduced pressure for 1.5 hours at 180 ° C., the reduced pressure was released, 1.7 g (0.009 mol) of trimellitic anhydride was added, and further heated from 180 ° C. to 220 ° C. under reduced pressure. A polyester was obtained by reacting at 3 ° C. for 3 hours. The number average molecular weight Mn of the obtained polyester was 4430, and the weight average molecular weight Mw was 8020. In addition, the ratio of the (R) -3-hydroxybutyric acid unit was 3.6 mol% with respect to all the structural units of the polyester among the structural units of the polyester [preparation of (R) -3-hydroxybutyric acid About 80% of the amount of (R) -3-hydroxybutyric acid was introduced into the polyester].

Comparative Example 1
A polyester was obtained in the same manner as in Example 1 except that trimellitic anhydride was not added. The number average molecular weight Mn of the obtained polyester was 1430, and the weight average molecular weight Mw was 6480. In addition, the ratio of the (R) -3-hydroxybutyric acid unit was 2.3 mol% with respect to all the structural units of the polyester among the structural units of the polyester [preparation of (R) -3-hydroxybutyric acid About 50% of the amount of (R) -3-hydroxybutyric acid was introduced into the polyester].

  In Example 1, compared with Comparative Example 1, the molecular weight of polyester and the introduction ratio of 3-hydroxybutyric acid increased. That is, it is thought that the reason why the molecular weight of the polyester obtained in Comparative Example 1 is lower than that in Example 1 is that unsaturated monocarboxylic acid was generated by intramolecular dehydration of 3-hydroxybutyric acid. In addition, the reason why the amount of 3-hydroxybutyric acid introduced into the polyester obtained in Comparative Example 1 is lower than that in Example 1 is that 3-hydroxybutyric acid in the polyester is eliminated by transesterification or decomposition. Conceivable.

  The polyester of the present invention can be used for paints, antistatic agents, inks, adhesives, pressure-sensitive adhesives, electrical / electronic materials (for example, carrier transport agents, luminous bodies, organic photoreceptors, etc.), electrical / electronic components or equipment (for example, optical Lenses, optical films, optical discs, inkjet printers, digital paper, organic semiconductor lasers, dye-sensitized solar cells, etc.), mechanical parts or equipment (for example, automobiles, aerospace materials, sensors, etc.). In particular, because of its high biodegradability, it can be used for molded parts in various fields (for example, molded bodies such as caging and housing), containers (food, daily necessities, electricity, electronic equipment, parts, etc.) by moldings such as extrusion molding and injection molding. The container may be suitably used for packaging materials and the like. The polyester resin includes a skeleton derived from hydroxyalkanoic acid and has biocompatibility, so that it can be used in the medical field (for example, medical devices).

Claims (8)

  A step of preparing a polyester precursor having at least a polymerization component of a dicarboxylic acid or a reactive derivative thereof, a diol, and a hydroxyalkanoic acid or an alkyl ester thereof, and having a hydroxyl group, the polyester precursor, a polycarboxylic acid or A method for producing a polyester having a branched structure, which comprises a step of reacting the reactive derivative with the chain to extend the chain. Hydroxyalkanoic acid or an alkyl ester thereof is represented by the following formula (1)

(In the formula, group R ¹ represents an alkyl group, group R ² represents a hydrogen atom or an alkyl group, and n represents an integer of 0 to 10.)
The production method according to claim 1, wherein the polycarboxylic acid or a reactive derivative thereof is an acid anhydride. The production method according to claim 1 or 2, wherein in formula (1), n is 1, the group R ¹ is a C _1-4 alkyl group, and the group R ² is a hydrogen atom or a C _1-2 alkyl group.   In the polyester precursor preparation step, the proportion of the diol is 102 to 130 mol with respect to 100 mol of the dicarboxylic acid or its reactive derivative, and the proportion of hydroxyalkanoic acid or its alkyl ester is the total number of moles of the entire polymerization component. The production method according to claim 1, wherein the content is 1 to 30 mol%.   The ratio of the carboxyl group or reactive derivative group of the polycarboxylic acid or its reactive derivative is 0.5 to 1 mol of hydroxyl group of the polyester precursor, with 1 mol of acid anhydride group as 2 mol of carboxyl group. It is 1.5 mol, The manufacturing method in any one of Claims 1-4.   Dicarboxylic acid or reactive derivative thereof, diol, hydroxyalkanoic acid or alkyl ester thereof as at least a polymerization component, and hydroxyl group of polyester precursor and carboxyl group of polycarboxylic acid or reactive derivative thereof are ester-bonded A polyester having a branched structure in which a chain is extended.   The polyester of claim 6 wherein the hydroxyalkanoic acid comprises 3-hydroxyalkanoic acid.   The polyester according to claim 6 or 7, wherein the weight average molecular weight is 7000 or more.