JP2014185331A - Polyester resin and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin enhancing the melt polycondensation reaction rate, without generating a gel causing a foreign substance, and being efficiently and stably produced, which is a high quality and high molecular weight polyester resin being excellent in flowability, hydrolysis resistance, thermostability and color tone and allowing reduction in foreign substance.SOLUTION: A polyester resin has a branch structure in a molecular chain, from a structural unit derived from dicarboxylic acid component, diol component, and triol component represented by the formula (3). (X is a C2 to 6 alkylene group; Y is a direct bond, a C1 to 10 alkylene group or an aralkylene group; and Z is a hydrogen atom or a methyl group.)

Description

  The present invention relates to a polyester resin and a method for producing the same, and more specifically, can be efficiently and stably produced, and has high fluidity, hydrolysis resistance, thermal stability, color tone, and high molecular weight with reduced foreign matter. The present invention relates to a polyester resin and a method for producing the same.

  Polyester resins occupy an important industrial position due to their excellent mechanical and chemical properties. For example, aromatic polyester resins such as polyethylene terephthalate and polybutylene terephthalate are resins with excellent heat resistance and chemical resistance. They are easy to process and economical, so they can be used for fibers, films, sheets, bottles, electrical and electronic parts, automobiles. It is widely used in the fields of extrusion molding and injection molding of parts and precision equipment parts.

  However, in recent years, the demand for smaller and lighter industrial molded products has been increasing, so it is desirable to improve the mechanical strength as well as improve the fluidity during melt molding. It is desired to efficiently produce such an aromatic polyester resin.

  As a method for efficiently producing an aromatic polyester resin having high fluidity, the fluidity is improved by adding a compound having three or more functional groups to Patent Document 1 in the course of producing the polyester resin. It is described. However, although the technique disclosed in Patent Document 1 can provide a good flowable aromatic polyester resin, there is a problem that thickening (gelation) occurs at the time of polymerization due to the addition of a polyfunctional branching agent, There was a problem that strength properties such as tensile breaking elongation and strain strength of the obtained polyester resin were lowered.

  On the other hand, aliphatic polyester resins such as polyethylene succinate and polybutylene succinate are attracting attention as environmentally friendly plastics due to the recent increase in awareness of environmental issues such as depletion of fossil fuels and increased carbon dioxide in the atmosphere. In the plastics industry as well, countermeasures against environmental problems that take into consideration the life cycle from product manufacture to disposal are urgently needed.

  An aliphatic dicarboxylic acid (for example, succinic acid or adipic acid) as a raw material for the aliphatic polyester resin can be produced from plant-derived glucose using a fermentation method, and an aliphatic diol (for example, ethylene glycol, 1,3-propane). Diol, 1,4-butanediol) can also be produced from plant-derived raw materials, so that resource saving of fossil fuels can be achieved. At the same time, the growth of plants absorbs carbon dioxide in the atmosphere, which can greatly contribute to the reduction of carbon dioxide emissions. Furthermore, since it exhibits excellent biodegradability, it can be said that the aliphatic polyester resin is a triple-friendly plastic.

  Conventionally, aromatic polyester resins such as polyethylene terephthalate and polybutylene terephthalate are generally used as resins for molding films, fibers, and other molded products. In order to obtain practical strength, the number average molecular weight is 1 Ten thousand was enough. In contrast, aliphatic polyester resins have a low melting point and a thermal decomposition, although it is necessary to increase the number average molecular weight to at least higher than that of aromatic polyester resins in order to obtain films and fibers having practical physical properties. It was difficult to obtain a high molecular weight aliphatic polyester resin because of its easy reaction.

The following proposals have been made in Patent Documents 2 to 5 for the purpose of producing a practical aliphatic polyester resin.
In Patent Documents 2 and 3, it is possible to obtain a high molecular weight aliphatic polyester resin containing a urethane bond by adding a diisocyanate compound as a coupling agent to a polyester diol having a hydroxyl group as a terminal group. Have been described. However, the aliphatic polyester resin containing a urethane bond has problems such as generation of microgel due to an increase in viscosity at the time of molding and easy coloring, and it cannot be said that the quality is sufficient.

  In Patent Documents 4 and 5, a fat having a large melt viscosity and a large weight average molecular weight relative to the number average molecular weight is obtained by copolymerizing a trifunctional polyhydric alcohol with a bifunctional aliphatic oxycarboxylic acid as an essential component. Although a method for producing a group polyester resin has been proposed, there are problems such as gelation due to the progress of the branching reaction and a slow polycondensation rate, and it has not been sufficient in terms of productivity and quality.

JP 2001-200038 A JP-A-4-189822 JP-A-5-287043 JP-A-8-259680 JP-A-11-130852

  In view of the above-mentioned conventional problems, the present invention can be applied to various fields such as extrusion molding and injection molding, and has high fluidity, hydrolysis resistance, thermal stability, color tone, and reduced foreign matter. An object of the present invention is to provide a polyester resin that can be efficiently and stably produced.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention can significantly increase the polycondensation rate by using a specific triol component when producing a polyester resin, and are excellent in quality. As a result, the present inventors have found that a polyester resin can be obtained.

  That is, the gist of the present invention resides in the following [1] to [13].

[1] A polyester resin containing a structural unit derived from a dicarboxylic acid component, a diol component, and a triol component in a molecular chain, represented by a branched structure represented by the following formula (1) and the following formula (2): A polyester resin containing a structural unit in the molecular chain.

(In the formula (1), X represents an alkylene group having 2 to 6 carbon atoms, Y represents a direct bond, an alkylene group having 1 to 10 carbon atoms, or an aralkylene group, and Z represents a hydrogen atom or a methyl group. In formula (2), R ₁ and R ₂ are each independently an alkylene group having 2 to 12 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a cycloalkylene alkylene group having 4 to 12 carbon atoms, or carbon. An arylene group having 4 to 25 carbon atoms, a heteroarylene group having 4 to 25 carbon atoms, or two or more of these alkylene group, cycloalkylene group, cycloalkylene alkylene group, arylene group, and heteroarylene group are directly or —O—, (It represents a divalent group formed by connecting through any one of —S—, —SO—, —SO ₂ —, —OSO ₂ — and —CO—).

[2] The polyester resin according to [1], wherein, in the formula (1), Y is a direct bond or a methylene group.

[3] The polyester resin according to [2], wherein in the formula (1), X is an ethylene group, Y is a methylene group, and Z is a hydrogen atom.

[4] The content of the branched structure represented by the formula (1) is more than 0 and 10 mol% or less with respect to the structural unit derived from the dicarboxylic acid component in the resin [1] to [3]. The polyester resin in any one of.

[5] Any of [1] to [4], wherein the dicarboxylic acid component is an aromatic dicarboxylic acid and / or an ester-forming derivative thereof, and the diol component is ethylene glycol and / or 1,4-butanediol. The polyester resin as described in.

[6] The polyester resin according to any one of [1] to [4], wherein the dicarboxylic acid component is an aliphatic dicarboxylic acid and / or an ester-forming derivative thereof, and the diol component is 1,4-butanediol. .

[7] The polyester resin according to [6], wherein the dicarboxylic acid component is succinic acid and / or adipic acid.

[8] An esterification process using a dicarboxylic acid component and a diol component to perform an esterification reaction or a transesterification reaction, and a melt polycondensation reaction process in which an oligomer obtained by the esterification process is subjected to a polycondensation reaction In the method for producing a resin, a method for producing a polyester resin, wherein a triol compound represented by the following formula (3) is added in an arbitrary step.

(However, in Formula (3), X represents a C2-C6 alkylene group, Y represents a direct bond, a C1-C10 alkylene group, or an aralkylene group, and Z represents a hydrogen atom or a methyl group. Represents.)

[9] The method for producing a polyester resin according to [8], wherein in the formula (3), Y is a direct bond or a methylene group.

[10] The method for producing a polyester resin according to [9], wherein in the formula (3), X is an ethylene group, Y is a methylene group, and Z is a hydrogen atom.

[11] Any of [8] to [10], wherein the dicarboxylic acid component is an aromatic dicarboxylic acid and / or an ester-forming derivative thereof, and the diol component is ethylene glycol and / or 1,4-butanediol. The manufacturing method of the polyester resin of description.

[12] The polyester resin according to any one of [8] to [10], wherein the dicarboxylic acid component is an aliphatic dicarboxylic acid and / or an ester-forming derivative thereof, and the diol component is 1,4-butanediol. Manufacturing method.

[13] The method for producing a polyester resin according to [12], wherein the dicarboxylic acid component is succinic acid and / or adipic acid.

  According to the present invention, by using a specific triol component, the melt polycondensation reaction rate is remarkably increased without generating a gel that causes foreign matters, and the fluidity, hydrolysis resistance, thermal stability, color tone are increased. It is possible to efficiently and stably produce a high-quality, high-molecular-weight polyester resin with reduced foreign matter, and can contribute to the expansion of the use of biomass-derived polyester resins.

  Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the examples and embodiments described below, and can be arbitrarily modified and implemented without departing from the gist of the present invention. I can do it.

  The polyester resin of the present invention is a polyester resin containing a structural unit derived from a dicarboxylic acid component, a diol component, and a triol component in a molecular chain, and has a branched structure represented by the following formula (1) and the following formula (2). Is contained in the molecular chain.

(In the formula (1), X represents an alkylene group having 2 to 6 carbon atoms, Y represents a direct bond, an alkylene group having 1 to 10 carbon atoms, or an aralkylene group, and Z represents a hydrogen atom or a methyl group. In formula (2), R ₁ and R ₂ are each independently an alkylene group having 2 to 12 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a cycloalkylene alkylene group having 4 to 12 carbon atoms, or carbon. An arylene group having 4 to 25 carbon atoms, a heteroarylene group having 4 to 25 carbon atoms, or two or more of these alkylene group, cycloalkylene group, cycloalkylene alkylene group, arylene group, and heteroarylene group are directly or —O—, (It represents a divalent group formed by connecting through any one of —S—, —SO—, —SO ₂ —, —OSO ₂ — and —CO—).

  Although there is no restriction | limiting in particular in the method of manufacturing the polyester resin of this invention, For example, it obtains by the esterification process which performs esterification reaction or transesterification using a dicarboxylic acid component and a diol component, and this esterification process. In a method for producing a polyester resin through a melt polycondensation reaction step in which a polycondensation reaction is performed on the resulting oligomer, a method for producing a polyester resin of the present invention, wherein a triol compound represented by the following formula (3) is added in an optional step Can be manufactured.

(However, in Formula (3), X represents a C2-C6 alkylene group, Y represents a direct bond, a C1-C10 alkylene group, or an aralkylene group, and Z represents a hydrogen atom or a methyl group. Represents.)

  In the present invention, the “dicarboxylic acid component” refers to the dicarboxylic acid and derivatives thereof described below, which are the raw materials for producing the polyester resin, and the same applies to the “diol component” and the “triol component”. In addition, “a structural unit derived from a dicarboxylic acid component, a diol component, and a triol component is included in the molecular chain”, “a branched structure represented by the following formula (1) and a structural unit represented by the following formula (2): “Contained in the molecular chain” means that the polymer chain constituting the molecule of the polyester resin contains a structural unit formed by the reaction of these raw material components in the production process of the polyester resin.

  Below, the manufacturing method of the polyester resin of this invention is demonstrated.

[Polyester resin raw material]
(Dicarboxylic acid component)
Specific examples of the dicarboxylic acid component used in the present invention include terephthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenylether dicarboxylic acid, 4,4′-benzophenone dicarboxylic acid, 4,4 Aromatic dicarboxylic acids such as' -diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 2,6-naphthalenedicarboxylic acid; 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1, Alicyclic dicarboxylic acids such as 4-cyclohexanedicarboxylic acid and 2,3-norbornenedicarboxylic acid; aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid These may be used alone. It may be used as a mixture of two or more. From the viewpoints of mechanical properties, wide application of the obtained polyester resin, availability of raw materials, and the like, aromatic dicarboxylic acid or aliphatic dicarboxylic acid is preferable, and aromatic dicarboxylic acid is more preferable. As the aromatic dicarboxylic acid, terephthalic acid and isophthalic acid are preferable, and as the aliphatic dicarboxylic acid, succinic acid and adipic acid are preferable.

  These dicarboxylic acid components can be used in the reaction as dicarboxylic acids, as dicarboxylic acid anhydrides, or as dicarboxylic acid derivatives such as alkyl esters of dicarboxylic acids, preferably dialkyl esters, such as dicarboxylic acids and dicarboxylic acid alkyl esters, etc. It may be used as a mixture with a dicarboxylic acid derivative. There are no particular restrictions on the alkyl group of the dicarboxylic acid alkyl ester, but if the alkyl group is long, the boiling point of the alkyl alcohol produced during the transesterification reaction will rise, and it will not volatilize from the reaction solution, resulting in a terminal stopper. In order to inhibit polycondensation, an alkyl group having 4 or less carbon atoms is preferable, and a methyl group is particularly preferable.

  In particular, the dicarboxylic acid component is preferably composed mainly of terephthalic acid and / or an ester-forming derivative thereof, or mainly composed of succinic acid and / or adipic acid. In the present specification, the “main component” means a component that is contained in the largest amount in terms of mole among components containing the same.

<Diol component>
Specific examples of the diol component used in the present invention include ethylene glycol, diethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, polyethylene glycol, polypropylene glycol, polytetra Aliphatic diols such as methylene glycol, dibutylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol; 1,2-cyclohexanediol, 1,4-cyclohexanediol Alicyclic diols such as 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclo [5.2.1.0 (2,6)] decandimethanol; 1,3- Zendimethanol, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, bis (4 -Hydroxyphenyl) sulfone, aromatic diols such as bis [4- (2-hydroxyethoxy) phenyl] sulfone; oxygen-containing alicyclic diols and ethylene glycols derived from plant materials such as isosorbide, isomannide, isoidet, erythritan, 3-propanediol, 1,4-butanediol, and the like can also be derived from plant raw materials. Among these, it is preferable to use ethylene glycol and 1,4-butanediol from the viewpoints of mechanical properties, wide use of the obtained polyester resin, availability of raw materials, and the like. These may be used alone or in combination of two or more.

  Among these, when the dicarboxylic acid component is an aromatic dicarboxylic acid and / or an ester-forming derivative thereof, the diol component is preferably ethylene glycol and / or 1,4-butanediol, and in particular, the dicarboxylic acid component is terephthalic acid and In the case of / or dimethyl terephthalate, it is preferable to use ethylene glycol and / or 1,4-butanediol as the diol component. In addition, when the dicarboxylic acid component is an aliphatic dicarboxylic acid and / or an ester-forming derivative thereof such as succinic acid and / or adipic acid, it is preferable to use 1,4-butanediol as the diol component. When the dicarboxylic acid component and the diol component are used in the above combination, the effects of the present invention are easily obtained, which is preferable.

  An intermediate obtained by reacting the dicarboxylic acid and diol in advance can also be used as a raw material. For example, when ethylene glycol is used as the diol component and terephthalic acid is used as the dicarboxylic acid component, bis (hydroxyethyl) terephthalate may be used.

  A suitable amount of such a diol component is different between the case of producing an aliphatic polyester resin and the case of producing an aromatic polyester resin, and is as follows.

(For the production of aliphatic polyester resin)
The molar ratio of the aliphatic diol component and the aliphatic dicarboxylic acid component in producing the aliphatic polyester resin varies depending on the type of raw material, but the lower limit of the amount of the aliphatic diol component relative to 1 mol of the aliphatic dicarboxylic acid component is Usually 0.70 mol, preferably 0.80 mol, more preferably 0.90 mol, particularly preferably 0.95 mol, and the upper limit is usually 3.0 mol, preferably 2.7 mol, more preferably Is 2.5 mol, particularly preferably 2.0 mol, most preferably 1.5 mol. If the ratio of the aliphatic diol component to the aliphatic dicarboxylic acid component is less than the above lower limit, the distillate distilled from the polycondensation reaction tank tends to increase the number of obstructive distillates and easily cause piping clogging. It is in. On the other hand, if the above upper limit is exceeded, the amount of diol component distilled out from the polycondensation reaction tank is large, the heat load becomes high, and it tends to be economically disadvantageous.

(For the production of aromatic polyester resin)
Among aromatic polyester resins, the molar ratio of the aliphatic diol component (ethylene glycol) to the aromatic dicarboxylic acid component (terephthalic acid) when producing a polyethylene terephthalate copolymer varies depending on the type of raw material, The lower limit of the amount of the aliphatic diol component relative to 1 mol of the aromatic dicarboxylic acid component is usually 0.95 mol, preferably 1.00 mol, more preferably 1.10 mol, and the upper limit is usually 3.0 mol, preferably 2.7 mol, more preferably 2.5 mol, particularly preferably 2.0 mol, most preferably 1.5 mol. If the ratio of ethylene glycol to terephthalic acid is less than the above lower limit, the distillate distilling from the polycondensation reaction tank tends to cause a blockage of distillate to easily cause piping blockage. On the other hand, when the above upper limit is exceeded, the amount of diol to be distilled from the polycondensation reaction tank is large, the heat load is high, and it tends to be economically disadvantageous.

Here, the “polyethylene terephthalate copolymer” refers to a polyester resin containing ethylene glycol as a diol component, terephthalic acid as a dicarboxylic acid component, and a specific triol component described later.
The “polybutylene terephthalate copolymer” refers to a polyester resin containing 1,4-butanediol as a diol component, terephthalic acid as a dicarboxylic acid component, and a specific triol component described later.

  In addition, the molar ratio of the aliphatic diol component (1,4-butanediol) to the aromatic dicarboxylic acid component (terephthalic acid) in producing the polybutylene terephthalate copolymer is the fat to 1 mol of the aromatic dicarboxylic acid component. The lower limit of the amount of the group diol component is usually 1.0 mol, preferably 1.2 mol, more preferably 1.5 mol, particularly preferably 2.0 mol, most preferably 2.2 mol, and the upper limit. Is usually 5.0 mol, preferably 4.5 mol, more preferably 4.0 mol, particularly preferably 3.8 mol, and most preferably 3.5 mol. If the ratio of 1,4-butanediol to terephthalic acid is less than the above lower limit, the esterification reaction rate may be lowered or the catalyst may be deactivated, which may impair the quality of the resin. Further, the distillate distilled from the polycondensation reaction tank tends to cause clogging of the piping due to the increase of clogging distillate. On the other hand, when the above upper limit is exceeded, the amount of by-products such as tetrahydrofuran tends to increase, which tends to be economically disadvantageous.

<Triol component>
In the present invention, a triol compound (triol component) represented by the following formula (3) is used as the third component of the polyester resin raw material.

(However, in Formula (3), X represents a C2-C6 alkylene group, Y represents a direct bond, a C1-C10 alkylene group, or an aralkylene group, and Z represents a hydrogen atom or a methyl group. Represents.)

  The triol component used in the present invention contains three hydroxyl groups, and the adjacent carbon atom (position 2) of the carbon atom (position 1) substituted by one hydroxyl group is a tertiary carbon atom or 4 When it is a secondary carbon atom, at least one substituent of the tertiary carbon atom or the quaternary carbon atom has a group containing a hydroxyl group at the terminal of an alkylene group having 2 or more carbon atoms and / or three hydroxyl groups And the hydroxyl group is adjacent to the carbon atom (position 2) of the carbon atom (position 1) substituted by one hydroxyl group, the carbon atom at position 2 is a secondary carbon atom or 3 It becomes a secondary carbon atom, but at least one substituent of the secondary carbon atom or tertiary carbon atom has a group containing a hydroxyl group at the terminal of an alkylene group having 2 or more carbon atoms. By using such a triol component, the polymerization reaction is controlled, and a suitable cross-linked structure is formed in the resulting polyester resin, so that the physical properties are easily improved.

  Examples of such triol components include 1,2,4-butanetriol, 2-hydroxymethyl-1,4-butanediol, 3-hydroxymethyl-1,5-pentanediol, 2-hydroxymethyl-1, 5-pentanediol, 1,2,5-pentanetriol, 1,2,6-hexanetriol, 1,2,7-heptanetriol, 2-hydroxymethyl-1,6-hexanediol, 3-hydroxymethyl-1 , 6-hexanediol, 2-hydroxymethyl-1,7-heptanediol, 3-hydroxymethyl-1,7-heptanediol, 4-hydroxymethyl-1,7-heptanediol, 2- [4-hydroxymethylphenyl ] -1,4-butanediol, 2- [4-hydroxymethylphenyl] -1,5-heptane Such as All, and the like. These triol components may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  Among these, from the viewpoint of viscosity control and terminal acid value at the time of polyester resin production, in the above formula (3), X is preferably an alkylene group having 2 to 6 carbon atoms and Y is a direct bond or a methylene group. More preferably, X is an alkylene group having 2 to 4 carbon atoms and Y is a direct bond or a methylene group. For example, 1,2,4-butanetriol and 2-hydroxymethyl-1,4-butanediol are preferable, and 2-hydroxymethyl-1,4-butanediol (in the above formula (3), X is an ethylene group, Y Is a methylene group and Z is a hydrogen atom).

  A suitable amount of such a triol component is different between the case of producing an aliphatic polyester resin and the case of producing an aromatic polyester resin, and is as follows.

(For the production of aliphatic polyester resin)
When an aliphatic polyester resin is produced, the lower limit of the amount of the triol component used is usually 0.01 mol%, preferably 0.05 mol%, more preferably 0 with respect to all dicarboxylic acid components used in the production of the polyester resin. 0.1 mol%, more preferably 0.15 mol%, particularly preferably 0.2 mol%, and the upper limit is usually 10 mol%, preferably 5 mol%, more preferably 3 mol%, still more preferably 1 mol% %, Particularly preferably 0.5 mol%.

  Further, the content of the structural unit derived from the triol component in the produced aliphatic polyester resin is usually 0.01 mol%, preferably 0, with respect to the structural unit derived from the dicarboxylic acid component in the polyester resin. 0.05 mol%, more preferably 0.1 mol%, still more preferably 0.15 mol%, particularly preferably 0.2 mol%, and the upper limit is usually 10 mol%, preferably 5 mol%, more preferably Is 3 mol%, more preferably 1 mol%, particularly preferably 0.5 mol%. In addition, content of the structural unit derived from the triol component in this aliphatic polyester resin is corresponded to the sum total of content of the branched structure represented by below-mentioned Formula (1), and content of a terminal cyclic ether group.

That is, in the production of the aliphatic polyester resin, since the substantial total amount of the triol component used as the polyester resin production raw material is contained as a structural unit of the molecular chain in the obtained polyester resin, The ratio of the triol component to the dicarboxylic acid component used in the production is almost equal to the ratio of the structural unit derived from the triol component to the structural unit derived from the dicarboxylic acid component contained in the obtained polyester resin.
In the aliphatic polyester resin, the substantial amount of the triol component used as a raw material for producing the polyester resin is contained as a structural unit of the molecular chain in the obtained polyester resin. This is because the reaction temperature in the resin production process is relatively low, and the triol component used as a raw material is introduced into the polyester resin without volatilization during the reaction.

  By using the triol component within the above range, the polycondensation rate can be increased in the aliphatic polyester resin, so that the polymerization temperature can be lowered, and the operation control range (process window) of the reaction conditions is widened. The advantage that it can be obtained.

(For the production of aromatic polyester resin)
In the case of producing an aromatic polyester resin, the lower limit of the amount of the triol component used is usually 0.02 mol%, preferably 0.1 mol%, more preferably with respect to all dicarboxylic acid components used in the production of the polyester resin. The upper limit is usually 20 mol%, preferably 15 mol%, more preferably 10 mol%, particularly preferably 5 mol%.

  The content of the structural unit derived from the triol component in the produced aromatic polyester resin is usually 0.01 mol%, preferably the lower limit relative to the structural unit derived from the dicarboxylic acid component in the polyester resin. Is 0.05 mol%, more preferably 0.1 mol%, particularly preferably 0.2 mol%, and the upper limit is usually 10 mol%, preferably 7.5 mol%, more preferably 5 mol%. Particularly preferred is 2.5 mol%. In addition, as described later, the content of the constituent unit derived from the triol component in the aromatic polyester resin is the content of the branched structure represented by the formula (1) and the content of the terminal cyclic ether group. Is equivalent to the sum of

In the production of the aromatic polyester resin, depending on the reaction conditions, about 50% of the triol component used as the polyester resin production raw material is contained as a structural unit of molecular chain in the polyester resin from which about 50% is obtained, and the remaining about 50%. Since% is extracted from the reaction system, the ratio of the structural unit derived from the triol component to the structural unit derived from the dicarboxylic acid component contained in the obtained polyester resin is about 50%.
In the production of the aromatic polyester resin, about 50% of the triol component used as the polyester resin production raw material is contained as a molecular chain constituent unit in the obtained polyester resin, and the remaining about 50% The reason why the reaction system is extracted is that, as will be described later, the reaction temperature of the aromatic polyester resin is relatively high, and part of the triol component of the raw material volatilizes and is extracted from the reaction system during the reaction.
The triol extracted out of the reaction system can be reused as a raw material as necessary by separating it from other components (diol and the like) by a recovery step such as distillation.

  By using a triol component in the above range, it is considered that some triols work as end-capping agents in aromatic polyester resins, which is thought to contribute to the prevention of gelation. The adjustment range of density and feed amount can be widened, and there is an advantage that handling becomes easy.

  In any case of the aliphatic polyester resin and the aromatic polyester resin, if the amount of the triol component used or the content of the structural unit derived from the triol component in the polyester resin is less than the above lower limit, the effect of the present invention hardly appears, There is a tendency that the effect of improving the polycondensation reaction rate, fluidity, hydrolysis resistance, thermal stability, and color tone is small. On the other hand, when the upper limit is exceeded, reaction control is difficult and stable production tends to be difficult. Moreover, the crystallinity of the obtained polyester resin is lost, and the moldability tends to decrease.

In the present invention, although the details of the mechanism of the above effect by using a triol component are not clear, the triol component used in the present invention is a tertiary carbon atom or a quaternary carbon atom substituted with a hydroxyl group or a hydroxymethyl group. This structure has a structure in which functional groups are bonded, and this structure is suitable for improving the flowability of the polyester resin because it maintains an appropriate branched structure. Further, since it has such a branched structure, melt polycondensation is possible. As a result, the color tone is considered to be improved.
In addition, for the improvement of hydrolysis resistance and thermal stability, the triol component is a linear alkylene group having an appropriate length for dehydration condensation between two hydroxyl groups in the molecule to form a cyclic ether structure. Therefore, a part of the polymer chain serves as an end-capping agent that substitutes the carboxyl group at the end of the polymer chain, or the terminal carboxyl group of the polyester molecular chain is substituted, or a system using 1,4-butanediol as the diol component Then, since the by-production of the terminal carboxyl group by Back-Biting reaction can be suppressed, it is thought that it contributes to the hydrolysis resistance and thermal stability improvement of the obtained polyester resin.

  As the terminal structure in which the cyclic ether structure introduced into the polyester resin by the triol component used in the present invention is formed, when X in the formula (3) representing the triol component is an ethylene group, the following formulas (4) to (10) (In the following formulas (4) to (8) and (10), Y and Z have the same meanings as in the formula (3)). In addition, the terminal structure represented by following formula (9) is a thing produced | generated by the reaction of the acetaldehyde byproduced by the system which used ethylene glycol as a diol component, and a triol component.

  Therefore, in order to introduce such a terminal structure for improving hydrolysis resistance and thermal stability, intramolecular dehydration condensation of two hydroxyl groups among the three hydroxyl groups possessed by the triol component in advance. Thus obtained alcohol compound having a cyclic ether structure can be added as a terminal blocking agent. As an example of the alcohol compound having such a cyclic ether structure, when X in the formula (3) is an ethylene group, a hydroxytetrahydrofuran compound represented by the following formulas (11a), (11b), (11d), Examples thereof include a hydroxydihydrofuran compound represented by the formula (11c) and a monohydroxydioxane compound represented by the following formula (11e). The alcohol compound represented by the following formula (11e) has a structure formed by reaction with acetaldehyde by-produced in a system using ethylene glycol (in the following formulas (11a) to (11d), Y, Z has the same meaning as in formula (3).

  The terminal structure having a cyclic ether structure as shown by the above formulas (4) to (10), that is, the content of the terminal cyclic ether group in the polyester resin is as described later as the content of the terminal cyclic ether group. is there. If the content of the terminal cyclic ether group in the polyester resin exceeds the upper limit described later, the polycondensation takes longer during the polycondensation reaction. There are cases where the number of groups increases, hydrolysis resistance and thermal stability decrease, and color tone deteriorates.

In the present invention, the addition time of the triol component at the time of production of the polyester resin is not particularly limited as long as it is before the polyester resin is produced, and it is added at any timing during the raw material charging, the esterification reaction, or the polycondensation reaction. It can also be added in multiple portions.
For the purpose of improving hydrolysis resistance, as described above, the triol component is subjected to intramolecular dehydration condensation in advance by a known method to obtain a monohydroxytetrahydrofuran or monohydroxydioxane compound, and then polycondensation from the raw material charge. It can be added at any timing during the reaction.

<Other copolymer components>
When manufacturing the polyester resin of this invention, you may copolymerize other components other than the said dicarboxylic acid component, a diol component, and a triol component. Other copolymerization components that can be used in this case include lactic acid, glycolic acid, hydroxybutyric acid, hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2- Hydroxyoxycaproic acid, malic acid, maleic acid, citric acid, fumaric acid and other oxycarboxylic acids; and esters, lactones, oxycarboxylic acid polymers of these oxycarboxylic acids, or propanetricarboxylic acid, pyromellitic acid, trimethyl Trifunctional or higher polyvalent carboxylic acids such as meritic acid benzophenone tetracarboxylic acid and anhydrides thereof, or erythritol, dipentaerythritol, pentaerythritol monostearate, 2,3,4-pentanetriol, 3-methyl-1, 3,5-pentanetriol, 1,2,3 Trifunctional or higher functional groups such as cyclohexanetriol, 1,2,3-hexanetriol, 1,2,3-heptanetriol, 3-hydroxyethyl-1,5-pentanediol, 2,4,6-heptanetriol, trimethylolethane, etc. And polyhydric alcohols. A tri- or higher-functional oxycarboxylic acid, a tri- or higher-functional carboxylic acid, a tri- or higher-functional alcohol, and the like can be easily obtained by adding a small amount thereof. Of these, oxycarboxylic acids such as malic acid, citric acid, and fumaric acid are preferable, and malic acid is particularly preferably used.

  When these other copolymerization components are used, the amount used is preferably 0.01 mol% or more, more preferably 0.05 mol%, preferably 1 mol, based on the dicarboxylic acid component used in the production of the polyester resin. % Or less, more preferably 0.5 mol% or less. By using other copolymer components, as described above, the viscosity of the resulting polyester resin can be increased, but if the amount used is too large, gelation tends to occur.

<Chain extender>
In the production of the polyester resin of the present invention, a chain extender such as a carbonate compound or a diisocyanate compound can also be used. However, the amount thereof is usually carbonate based on the structural units derived from all monomers constituting the polyester resin. The amount is preferably such that the bonds and urethane bonds are 10 mol% or less. However, when the polyester resin of the present invention is used as a biodegradable resin, diisocyanate has a problem that a highly toxic diamine is generated during the decomposition process and may accumulate in the soil, and is generally used as a carbonate compound. The diphenyl carbonate system also has a problem that the highly toxic by-product phenol and unreacted diphenyl carbonate remain in the polyester resin, so the amount used is based on the units derived from all monomers constituting the polyester resin, The carbonate bond is preferably less than 1 mol%, more preferably 0.5 mol% or less, particularly preferably 0.1 mol%, and the urethane bond is preferably less than 0.06 mol%, more preferably 0.01 mol%. The amount is such that it is not more than mol%, particularly preferably not more than 0.001 mol%.

[Production of polyester resin]
As a method for producing a polyester resin in the present invention, a conventionally known method except that a triol component is added at any stage of raw material charging, esterification reaction or polycondensation reaction before the polyester resin is produced. For example, a melt polycondensation reaction in which a polycondensation reaction is performed under reduced pressure after performing an esterification reaction and / or a transesterification reaction between the dicarboxylic acid component and the diol component (and triol component) described above. Although it can be produced by a general method or a known solution heating dehydration condensation method using an organic solvent, polyester is obtained by a melt polycondensation method performed in the absence of a solvent from the viewpoint of economy and simplicity of the production process. It is preferable to produce a resin.

  Moreover, each reaction at the time of manufacturing a polyester resin in this invention can be performed by a batch method or a continuous method.

  As a method for producing a polyester resin by the melt polycondensation method, melt polycondensation is carried out in two stages of an esterification and / or transesterification step and a reduced pressure polycondensation step using the same or different reactors. Examples of the polycondensation reactor include a method using a stirred tank reactor equipped with a vacuum exhaust pipe connecting the vacuum pump and the reactor. In addition, a method is preferred in which a condenser is connected between the vacuum exhaust pipe connecting the vacuum pump and the reactor, and the volatile components and unreacted monomers generated during the polycondensation reaction are recovered by the condenser. Used.

  In the method for producing a polyester resin according to the present invention, after the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component (and triol component), the carboxylic acid terminal and alcohol terminal of the polyester resin are performed under reduced pressure. A method of increasing the degree of polymerization of the polyester resin while distilling off water or diol produced by ester exchange reaction and / or transesterification reaction between alcohol ends, or dicarboxylic acid and / or its from the carboxylic acid end of the polyester resin A method of increasing the degree of polymerization of the polyester resin while distilling off the acid anhydride is used.

  Hereinafter, the production method of the aliphatic polyester resin by the batch method and the production method of the aromatic polyester resin by the batch method will be described in detail. However, the production method of the present invention is not limited to this unless it exceeds the gist of the present invention. It is not something.

<Method for producing aliphatic polyester resin>
In the present invention, the reaction conditions for the esterification and / or transesterification step when producing the aliphatic polyester resin can be set as follows.
The lower limit of the reaction temperature is usually 150 ° C., preferably 180 ° C., more preferably 200 ° C., and the upper limit is usually 250 ° C., preferably 240 ° C., more preferably 230 ° C. If the reaction temperature is less than the lower limit, the esterification reaction rate is slow and the reaction time tends to be long. On the other hand, when the above upper limit is exceeded, there is a tendency that foreign matter generation due to an increase in scattered matter in the reaction tank and decomposition of the aliphatic diol component and the aliphatic dicarboxylic acid component increase. In addition, the aliphatic polyhydric alcohol compound becomes a branching base point and tends to cause gelation.

  The lower limit of the reaction pressure is usually 50 kPa, preferably 60 kPa, more preferably 70 kPa, and the upper limit is usually 200 kPa, preferably 130 kPa, more preferably 110 kPa. If the reaction pressure is less than the above lower limit, the amount of scattered matter in the reaction tank increases, the haze of the reaction product increases, and it is easy to cause an increase in foreign matter, and the distillation of aliphatic diol components to the outside of the reaction system increases, resulting in a polycondensation reaction rate. It tends to cause a decrease in On the other hand, if the upper limit is exceeded, dehydration decomposition of the aliphatic diol component increases, and the polycondensation rate tends to decrease.

  The reaction time is usually 1 hour or longer, and the upper limit is usually 10 hours or shorter, preferably 4 hours or shorter.

The reaction conditions of the reduced pressure polycondensation reaction step when producing the aliphatic polyester resin in the present invention can be set as follows.
The lower limit of the reaction temperature is usually 180 ° C., preferably 200 ° C., more preferably 220 ° C., and the upper limit is usually 270 ° C., preferably 265 ° C., more preferably 260 ° C. If the reaction temperature is less than the lower limit, the polycondensation reaction rate tends to be slow and a long reaction time tends to be required. Also, the melt viscosity becomes too high, and it is not easy to extract the polymer. On the other hand, when the above upper limit is exceeded, there is a tendency that foreign matter generation due to an increase in scattered matter in the reaction tank and decomposition of the aliphatic diol component and the aliphatic dicarboxylic acid component increase. Further, the polyhydric alcohol compound becomes a branching base point and tends to cause gelation.

  The lower limit of the final ultimate pressure during the polycondensation reaction is usually 0.01 kPa, preferably 0.05 kPa, more preferably 0.1 kPa, and the upper limit is usually 1 kPa, preferably 0.8 kPa, more preferably 0.5 kPa. An attempt to make the reaction pressure below the lower limit requires an expensive vacuum device and is not economical. On the other hand, if the upper limit is exceeded, the polycondensation rate tends to decrease, and side reactions starting from the alcohol terminal proceed, and the terminal acid value tends to increase.

  The reaction time is usually 1 hour or longer, and the upper limit is usually 10 hours or shorter, preferably 4 hours or shorter.

  In the esterification and / or transesterification reaction step and the polycondensation reaction step, the reaction is promoted by using a reaction catalyst. However, in the esterification and / or transesterification reaction step, a sufficient reaction rate can be obtained without an esterification reaction catalyst, and water generated by the esterification reaction when an esterification reaction catalyst is present during the esterification reaction. As a result, the catalyst generates a precipitate insoluble in the reaction product, which may impair the transparency of the resulting aliphatic polyester resin (that is, haze increases) and may become a foreign substance. It is preferable that no additive is used.

In the polycondensation reaction step, the reaction is difficult to proceed without a catalyst, and a catalyst is preferably used.
As the polycondensation reaction catalyst, a metal compound containing at least one of the metal elements of Groups 1 to 14 of the periodic table is generally used. Specific examples of the metal element include scandium, yttrium, samarium, titanium, zirconium, vanadium, chromium, molybdenum, tungsten, tin, antimony, cerium, germanium, zinc, cobalt, manganese, iron, aluminum, magnesium, and calcium. , Strontium, sodium and potassium. Among them, scandium, yttrium, titanium, zirconium, vanadium, molybdenum, tungsten, zinc, iron, and germanium are preferable, and titanium, zirconium, tungsten, and germanium are particularly preferable.

  Furthermore, in order to reduce the terminal acid value that affects the thermal stability of the aliphatic polyester resin, among the above metal elements, metal elements of Group 3 to 6 of the periodic table showing Lewis acidity are preferable. Specifically, scandium, titanium, zirconium, vanadium, molybdenum, and tungsten are preferable, and titanium and zirconium are particularly preferable from the viewpoint of availability, and titanium is more preferable from the viewpoint of reaction activity.

  Examples of the catalyst include compounds containing organic groups such as carboxylate salts, alkoxy salt organic sulfonates or β-diketonate salts containing these metal elements, inorganic compounds such as metal oxides and halides described above, and the like. Is preferably used.

  The catalyst is preferably a compound that is liquid at the time of polycondensation or dissolved in an ester low polymer or a polyester resin because the polycondensation rate increases when it is in a melted or dissolved state during polycondensation.

  The polycondensation is preferably carried out without a solvent, but separately from this, a small amount of solvent may be used to dissolve the catalyst. Examples of the solvent for dissolving the catalyst include alcohols such as methanol, ethanol, isopropanol and butanol; diols such as ethylene glycol, butanediol and pentanediol; ethers such as diethyl ether and tetrahydrofuran; and nitriles such as acetonitrile. Hydrocarbon compounds such as heptane and toluene; water and mixtures thereof, and the like. These solvents are used so that the catalyst concentration is usually 0.0001 wt% or more and 99 wt% or less.

  As a titanium compound used as a polycondensation catalyst, tetraalkyl titanate and its hydrolyzate are preferable, and specifically, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-t-butyl. Examples include titanate, tetraphenyl titanate, tetracyclohexyl titanate, tetrabenzyl titanate and mixed titanates thereof, and hydrolysates thereof. In addition, titanium (oxy) acetylacetonate, titanium tetraacetylacetonate, titanium (diisoproxide) acetylacetonate, titanium bis (ammonium lactate) dihydroxide, titanium bis (ethylacetoacetate) diisopropoxide, titanium (triethanolaminate) ) Isopropoxide, polyhydroxytitanium stearate, titanium lactate, titanium triethanolamate, butyl titanate dimer and the like are also preferably used. Moreover, the liquid substance obtained by mixing alcohol, an alkaline-earth metal compound, a phosphate ester compound, and a titanium compound is also used.

  Among these, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, titanium (oxy) acetylacetonate, titanium tetraacetylacetonate, titanium bis (ammonium lactate) dihydroxide, polyhydroxytitanium stearate Preferred is a liquid obtained by mixing rate, titanium lactate, butyl titanate dimer, and alcohol, alkaline earth metal compound, phosphate ester compound, and titanium compound. Tetra-n-butyl titanate, titanium (oxy) ) Acetylacetonate, titanium tetraacetylacetonate, polyhydroxytitanium stearate, titanium lactate, butyl titanate dimer, alcohol, alkaline earth metal compound phosphorus A liquid obtained by mixing an ester compound and a titanium compound is more preferable, in particular, tetra-n-butyl titanate, polyhydroxy titanium stearate, titanium (oxy) acetylacetonate, titanium tetraacetylacetonate, and A liquid material obtained by mixing an alcohol, an alkaline earth metal compound, a phosphate ester compound, and a titanium compound is preferable.

  Specific examples of the zirconium compound used as the polycondensation catalyst include zirconium tetraacetate, zirconium acetate hydroxide, zirconium tris (butoxy) stearate, zirconyl diacetate, zirconium oxalate, zirconyl oxalate, potassium potassium oxalate, Illustrative are polyhydroxyzirconium stearate, zirconium ethoxide, zirconium tetra-n-propoxide, zirconium tetraisopropoxide, zirconium tetra-n-butoxide, zirconium tetra-t-butoxide, zirconium tributoxyacetylacetonate and mixtures thereof Is done. Among these, zirconyl diacetate, zirconium tris (butoxy) stearate, zirconium tetraacetate, zirconium acetate hydroxide, zirconium ammonium oxalate, potassium zirconium oxalate, polyhydroxyzirconium stearate, zirconium tetra-n-propoxide, Zirconium tetraisopropoxide, zirconium tetra-n-butoxide, zirconium tetra-t-butoxide are preferred, zirconyl diacetate, zirconium tetraacetate, zirconium acetate hydroxide, zirconium tris (butoxy) stearate, zirconium ammonium oxalate, zirconium tetra -N-propoxide, zirconium tetra-n-butoxide are more preferred, Preferred for reasons of zirconium tris (butoxy) stearate is readily obtained polyester resin having a high polymerization degree without colored.

  Specific examples of the germanium compound used as the polycondensation catalyst include inorganic germanium compounds such as germanium oxide and germanium chloride, and organic germanium compounds such as tetraalkoxygermanium. From the viewpoint of price and availability, germanium oxide, tetraethoxygermanium and mu and tetrabutoxygermanium are preferable, and germanium oxide is particularly preferable.

  In the present invention, in addition to the polycondensation catalyst, a promoter such as an alkaline earth metal compound or an acidic phosphate compound can be used.

  Specific examples of the alkaline earth metal compound include various compounds of beryllium, magnesium, calcium, strontium, and barium. Magnesium and calcium compounds are preferable from the viewpoint of handling and availability, and catalytic effect. A magnesium compound having an excellent catalytic effect is preferred. Specific examples of the magnesium compound include magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, magnesium hydrogen phosphate, and the like. Among these, magnesium acetate is preferable. These alkaline earth metal compounds may be used alone or in combination of two or more.

  As the acidic phosphate compound, those having an ester structure of phosphoric acid having at least one hydroxyl group represented by the following general formula (i) and / or (ii) are preferably used.

(In the above formula, R, R ′, and R ″ each independently represent an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group, an aryl group, or a 2-hydroxyethyl group. In the formula (i), R and R ′ represent They may be the same or different.)

  Specific examples of such acidic phosphate ester compounds include methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, octyl acid phosphate, and the like, and ethyl acid phosphate and butyl acid phosphate are preferred. These acidic phosphate ester compounds may be used alone or in combination of two or more.

  The acidic phosphate compound includes a diester form represented by the above general formula (i) and a monoester form represented by the above general formula (ii). From the reason that a catalyst exhibiting activity is obtained, it is preferable to use a monoester or a mixture of a monoester and a diester. 20-80: 80-20 are preferable, as for the mixing weight ratio (monoester body: diester body) of a monoester body and a diester body, More preferably, it is 30-70: 70-30, Most preferably, it is 40-60: 60-40.

  Moreover, the catalyst in this invention can be manufactured by mixing the titanium compound shown above, an alkaline-earth metal compound, and an acidic phosphate compound. When mixing the catalyst components, a solvent is usually used. The solvent to be used is not particularly limited as long as it can make the titanium compound, the alkaline earth metal compound, and the acidic phosphoric acid ester compound into a uniform solution, but alcohol is usually used.

That is, the catalyst in the present invention is preferably produced by mixing an alcohol, a titanium compound, an alkaline earth metal compound, and an acidic phosphate ester compound. The catalyst in the present invention is particularly preferably produced by mixing an alcohol, a titanium compound, an alkaline earth metal compound, and an acidic phosphate compound and concentrating the mixture.
In the present invention, the alcohol used for the production of the catalyst may be any alcohol as long as it becomes a homogeneous solution by mixing a titanium compound, an alkaline earth metal compound, and an acidic phosphate ester compound. Among them, methanol, ethanol, Examples thereof include monohydric alcohols such as butanol, propanol and 2-ethylhexanol, and dihydric alcohols such as ethylene glycol and 1,4-butanediol. These alcohols may be used alone or in combination of two or more. In the case of monohydric alcohols, the solubility of the compounds and the ease of handling are particularly high for titanium compounds, alkaline earth metal compounds, and acidic phosphate ester compounds. When the reaction solution is concentrated, the boiling point is low. Ethanol is preferred because it is low and easy to remove. On the other hand, in the case of a divalent alcohol, since the concentration operation is unnecessary, the same component as the diol component of the raw material is preferably used, and 1,4-butanediol is more preferably used.

  The content of titanium atom, alkaline earth metal atom and phosphorus atom in the catalyst used in the present invention is such that the content of titanium atom is T (molar basis) and the content of alkaline earth metal is M (molar basis). Assuming that the phosphorus atom content is P (molar basis), the lower limit of T / P (molar ratio) is usually 0.1, preferably 0.3, more preferably 0.5, particularly preferably 0.8. The upper limit is usually 5.5, preferably 4.0, more preferably 3.0, particularly preferably 1.5, and most preferably 1.0. If it is below the above upper limit, the polyester resin produced is less colored, the catalyst stability is good, the catalyst is not easily deactivated, and the risk of deteriorating the quality of the product due to the catalyst deactivation being mixed into the product Tend to be low. On the other hand, if it is at least the above lower limit, the catalytic activity tends to be high.

  On the other hand, the lower limit of M / P (molar ratio) is usually 0.1, preferably 0.5, more preferably 0.7, particularly preferably 0.9, and the upper limit is usually 5.5, preferably 3 0.0, more preferably 2.0, particularly preferably 1.5, still more preferably 1.2, and most preferably 1.1. When the amount is not more than the above upper limit, the thermal stability of the polyester resin obtained using this catalyst tends to be good. In addition, alkaline earth metals tend not to precipitate. On the other hand, if it is at least the above lower limit, the catalytic activity is high and the amount of terminal COOH tends not to increase.

  When these metal compounds are used as the polycondensation catalyst, the amount of catalyst added is usually 0.1 wtppm or more, preferably 0.5 wtppm or more, more preferably 1 wtppm or more, as the metal amount with respect to the aliphatic polyester resin to be produced. The upper limit is usually 10000 wtppm or less, preferably 1000 wtppm or less, more preferably 500 wtppm or less, still more preferably 200 wtppm or less, and particularly preferably 150 wtppm or less. If the amount of the catalyst used is too large, it is not only economically disadvantageous, but also increases the terminal acid value at the time of extracting the polymer, and tends to decrease the thermal stability and hydrolysis resistance of the polyester resin. On the other hand, when the amount is too small, the polycondensation activity is lowered, and thermal decomposition of the polyester resin is induced during production, and it tends to be difficult to obtain a polyester resin exhibiting practically useful physical properties.

  In particular, the content of titanium atoms contained in the aliphatic polyester resin obtained in the present invention is, as a titanium atom equivalent, the lower limit is usually 0.1 wtppm or more, preferably 0.5 wtppm or more, more preferably 1 wtppm or more, still more preferably. Is 5 wtppm or more, particularly preferably 10 wtppm or more, and the upper limit is usually 10,000 wtppm or less, preferably 1000 wtppm or less, more preferably 500 wtppm, still more preferably 200 wtppm or less, and particularly preferably 150 ppm or less. When the titanium atom content exceeds the above upper limit, the terminal acid value increases and the resin tends to be colored. On the other hand, when it is less than the above lower limit, the polycondensation rate is slow, and it tends to be difficult to obtain a highly viscous polyester resin.

  The position of addition of the polycondensation catalyst to the reaction system is not particularly limited as long as it is before the polycondensation reaction step, and may be added at the time of charging the raw material, but a large amount of unreacted dicarboxylic acid or water is present or generated. If the catalyst coexists under the circumstances, the catalyst may be deactivated and foreign matter may be deposited, which may impair the quality of the product. Therefore, it is preferably added after the esterification reaction step.

The reduced viscosity (η _sp / c) value of the aliphatic polyester resin produced in the present invention can be controlled by polycondensation time, polycondensation temperature, polycondensation pressure, and the like. The reduced viscosity has a lower limit of usually 1.6 dl / g or more, preferably 2.0 dl / g or more, more preferably 2.2 dl / g or more, particularly preferably, because the practically sufficient mechanical properties of the polyester resin can be obtained. Is 2.3 dl / g or more. From the viewpoint of ease of extraction after the polycondensation reaction of the polyester resin and operability such as ease of molding, the upper limit is usually 6.0 dl / g or less, preferably 5.0 dl / g or less. Preferably it is 4.0 dl / g or less.

  The reduced viscosity of the aliphatic polyester resin is measured by the method described in the Examples section below.

  Since the aliphatic polyester resin obtained by the present invention has a feature of low terminal acid value, it has excellent hydrolysis resistance, and has a low quality deterioration during storage and a small deterioration rate of a molded product. The terminal acid value of the aliphatic polyester resin of the present invention can be controlled by the polycondensation temperature, the catalyst amount, the added amount of the triol component, and the like, and the upper limit is usually 40 μeq, although it depends on the degree of polymerization of the aliphatic polyester resin. / G or less, preferably 30 μeq / g or less, more preferably 23 μeq / g or less, still more preferably 21 μeq / g or less, and particularly preferably 20 μeq / g or less. On the other hand, the lower limit is better, but it is usually 0.1 μequivalent / g or more, preferably 1 μequivalent / g or more.

  The terminal acid value of the aliphatic polyester resin is measured by the method described in the Examples section below.

  Since the aliphatic polyester resin obtained by the present invention has a feature that there are few terminal vinyl groups, there are few chain extensions and crosslinks based on unsaturated groups at the time of melting. In addition, the color of the product is excellent. The terminal vinyl group of the aliphatic polyester resin of the present invention can be controlled by the polycondensation temperature, the residence time, the added amount of the triol component, etc., and the upper limit is usually 30 μeq / g or less, preferably 20 μeq / g or less, More preferably, it is 15 micro equivalent / g or less, More preferably, it is 10 micro equivalent / g or less, Most preferably, it is 8 micro equivalent / g or less. On the other hand, the lower limit is better, but it is usually 0.1 μequivalent / g or more.

  The terminal vinyl group of the aliphatic polyester resin is measured by the method described in the Examples section below.

  The aliphatic polyester resin obtained by the present invention has a characteristic of good color tone. The YI value that is an index of color tone can be controlled by the polycondensation temperature, the amount of catalyst, the amount of triol component added, etc., preferably -5.0 to 10.0, and the upper limit is more preferably 6 or less. It is. If the YI value exceeds the above upper limit, it may be unfavorable due to yellowishness when formed into a molded product.

  The YI value of the aliphatic polyester resin is measured by the method described in the Examples section below.

In addition, the optional step of the production process of the aliphatic polyester resin or the resulting aliphatic polyester resin, various additives such as heat stabilizers, antioxidants, crystal nucleating agents, as long as the properties are not impaired. You may add a flame retardant, an antistatic agent, a mold release agent, a ultraviolet absorber, etc.
In addition, when molding the aliphatic polyester resin, in addition to the above-mentioned various additives, reinforcing agents and extenders such as glass fiber, carbon fiber, titanium whisker, mica, talc, CaCO ₃ , TiO ₂ and silica are added. Can also be molded.

<Method for producing aromatic polyester resin>
(Production method of polyethylene terephthalate copolymer)
In the present invention, esterification reaction and / or transesterification reaction conditions and polycondensation reaction conditions in producing an aromatic polyester are arbitrary as long as the reaction can proceed, but a polyethylene terephthalate copolymer is taken as an example. Then you can set as follows.

  As for the reaction temperature of esterification reaction and / or transesterification, the lower limit is usually 150 ° C., preferably 180 ° C., more preferably 200 ° C., and the upper limit is usually 270 ° C., preferably 260 ° C., more preferably 250 ° C. It is. If the reaction temperature is less than the lower limit, the esterification reaction and / or transesterification reaction rate is slow and the reaction time tends to be long. On the other hand, when the above upper limit is exceeded, there is a tendency that foreign matter is generated due to an increase in the amount of scattered matter in the reaction tank and that the amount of ethylene glycol and terephthalic acid decomposed increases. In addition, the triol component serves as a starting point for branching and tends to cause gelation.

  The lower limit of the esterification reaction and / or transesterification reaction pressure is usually 50 kPa, preferably 60 kPa, more preferably 70 kPa, and the upper limit is usually 200 kPa, preferably 130 kPa, more preferably 110 kPa. If the reaction pressure is less than the above lower limit, the amount of scattered matter in the reaction tank increases, the haze of the reaction product increases, and it is easy to increase foreign matter, and the distillation of aliphatic diol components to the outside of the reaction system increases and the reaction rate decreases. Tend to invite. On the other hand, if the upper limit is exceeded, dehydration decomposition of the diol component increases, and the polycondensation rate tends to decrease.

  The reaction time is usually 1 hour or longer, and the upper limit is usually 10 hours or shorter, preferably 4 hours or shorter.

  The lower limit of the reaction temperature in the reduced pressure polycondensation reaction step is usually 260 ° C., preferably 265 ° C., more preferably 270 ° C., and the upper limit is usually 290 ° C., preferably 285 ° C., more preferably 280 ° C. If the reaction temperature is less than the lower limit, the polycondensation reaction rate tends to be slow and a long reaction time tends to be required. Also, the melt viscosity tends to be too high and the polymer cannot be easily extracted. On the other hand, when the above upper limit is exceeded, there is a tendency that foreign matter generation due to an increase in scattered matter in the reaction tank and decomposition of ethylene glycol and terephthalic acid increase. In addition, the triol component serves as a starting point for branching and tends to cause gelation.

  The lower limit of the final ultimate pressure during the polycondensation reaction is usually 0.01 kPa, preferably 0.05 kPa, more preferably 0.1 kPa, and the upper limit is usually 1 kPa, preferably 0.8 kPa, more preferably 0.5 kPa. An attempt to make the reaction pressure below the lower limit requires an expensive vacuum device and is not economical. On the other hand, if the upper limit is exceeded, the polycondensation rate tends to decrease, and side reactions starting from the alcohol terminal proceed, and the terminal acid value tends to increase.

  The reaction time is usually 1 hour or longer, and the upper limit is usually 10 hours or shorter, preferably 4 hours or shorter.

In the esterification and / or transesterification reaction step and the polycondensation reaction step, the reaction is promoted by using a catalyst. However, when an aromatic dicarboxylic acid such as terephthalic acid is used as a raw material, a sufficient reaction rate tends to be obtained even in the absence of an esterification reaction catalyst in esterification.
On the other hand, when a dicarboxylic acid diester such as dimethyl terephthalate is used, it is preferable to use an alkaline earth metal such as Ca or Mg or a transition metal such as Mn or Zn as the transesterification catalyst.

  In the polycondensation reaction step, the reaction is difficult to proceed without a catalyst, and a catalyst is preferably used. As the polycondensation reaction catalyst, a metal compound containing at least one of the metal elements of Groups 1 to 14 of the periodic table is generally used. Specifically, as the metal element of the catalyst, scandium, yttrium, samarium, titanium, zirconium, vanadium, chromium, molybdenum, tungsten, tin, antimony, cerium, germanium, zinc, cobalt, manganese, iron, aluminum, magnesium, Examples include calcium, strontium, sodium and potassium. Among them, scandium, yttrium, titanium, zirconium, vanadium, molybdenum, tungsten, zinc, iron, and germanium are preferable, and titanium, antimony, zirconium, tungsten, and germanium are particularly preferable.

  In the present invention, in addition to the polycondensation catalyst, a promoter such as an alkaline earth metal compound or a phosphate compound can be used.

  Specific examples of the alkaline earth metal compound include various compounds of beryllium, magnesium, calcium, strontium, and barium, but lithium, sodium, potassium, magnesium, calcium from the viewpoint of handling and availability, and catalytic effect. Of these, preferred is a magnesium or lithium compound having excellent catalytic effect, and particularly preferred is a magnesium compound. Specific examples of the magnesium compound include magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, magnesium hydrogen phosphate, and the like. Among these, magnesium acetate is preferable. These may be used alone or in combination of two or more.

  Specific examples of phosphorus compounds include orthophosphoric acid, polyphosphoric acid, trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris (triethylene glycol) phosphate. Methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, triethylene glycol acid phosphate, etc. Among them, normal phosphoric acid is preferable.

  Specific examples of the polycondensation catalyst include metal compounds of the polycondensation catalyst exemplified in the description of the method for producing an aliphatic polyester resin.

  The amount of catalyst added when these metal compounds are used as the polycondensation catalyst, the lower limit is usually 1 wtppm or more, preferably 5 wtppm or more, and the upper limit is usually 1000 wtppm or less, preferably 500 wtppm or less More preferably, it is 300 wtppm or less, More preferably, it is 200 wtppm or less, Especially preferably, it is 150 wtppm or less. If the amount of catalyst used is too large, it is not only economically disadvantageous, but also increases the terminal acid value at the time of extracting the polymer, and tends to decrease the thermal stability and hydrolysis resistance of the polyethylene terephthalate copolymer. is there. On the other hand, if the amount is too small, the polycondensation activity becomes low, and thermal decomposition of the polyester resin is induced during production, and it tends to be difficult to obtain a polyethylene terephthalate copolymer showing practically useful physical properties.

  The addition position of the catalyst to the reaction system is not particularly limited as long as it is before the polycondensation reaction step, and may be added at the time of charging the raw material, but a large amount of unreacted dicarboxylic acid and water are present or generated. If the catalyst coexists under the circumstances, the catalyst is deactivated and foreign matter may be precipitated, which may impair the quality of the product. Therefore, it is preferably added after the esterification reaction step.

(Method for producing polybutylene terephthalate copolymer)
Taking a polybutylene terephthalate copolymer as an example, esterification reaction and / or transesterification reaction conditions and polycondensation reaction conditions can be set as follows.

  As for the reaction temperature of esterification reaction and / or transesterification, the lower limit is usually 180 ° C., preferably 200 ° C., more preferably 210 ° C., and the upper limit is usually 260 ° C., preferably 245 ° C., more preferably 235 ° C. It is. If the reaction temperature is less than the lower limit, the esterification reaction and / or transesterification reaction rate is slow and the reaction time tends to be long. On the other hand, when the above upper limit is exceeded, the amount of tetrahydrofuran generated due to thermal decomposition of 1,4-butanediol increases, and there is a tendency for foreign substances to be generated due to increased scattered matter in the reaction tank.

  The lower limit of the esterification reaction and / or transesterification reaction pressure is usually 10 kPa, preferably 13 kPa, more preferably 50 kPa, particularly preferably 60 kPa, and the upper limit is usually 133 kPa, preferably 101 kPa, more preferably 90 kPa, Particularly preferred is 80 kPa.

  If the reaction pressure is less than the above lower limit, the amount of scattered matter in the reaction vessel increases, the haze of the reaction product tends to increase, and foreign matter tends to increase, and 1,4-butanediol is not distilled out of the reaction system. It tends to cause a decrease in the polycondensation reaction rate. On the other hand, when the above upper limit is exceeded, the amount of tetrahydrofuran generated by thermal decomposition of 1,4-butanediol increases, which tends to be economically disadvantageous.

  The reaction time is usually 0.5 to 10 hours, preferably 1 to 8 hours, and more preferably 2 to 6 hours.

  The lower limit of the reaction temperature in the reduced pressure polycondensation reaction step is usually 210 ° C, preferably 225 ° C, more preferably 230 ° C, and the upper limit is usually 280 ° C, preferably 265 ° C, more preferably 255 ° C. If the reaction temperature is less than the lower limit, the polycondensation reaction rate tends to be slow and a long reaction time tends to be required. Also, the melt viscosity may become too high, making it difficult to extract the polymer. On the other hand, when the above upper limit is exceeded, foreign matter generation due to an increase in the amount of scattered matter in the reaction tank increases, or side reaction due to resin coloring or Back-Biting reaction proceeds, which tends to increase the terminal acid value. Further, the polyhydric alcohol compound becomes a branching base point and tends to cause gelation.

  The lower limit of the final ultimate pressure during the polycondensation reaction is usually 0.01 kPa, preferably 0.05 kPa, more preferably 0.1 kPa, and the upper limit is usually 1 kPa, preferably 0.8 kPa, more preferably 0.5 kPa. If the reaction pressure is to be made lower than the above lower limit, an expensive vacuum device is required, which tends to be uneconomical. On the other hand, if the upper limit is exceeded, the polycondensation rate tends to decrease, and a side reaction due to the back-biting reaction proceeds, and the terminal acid value tends to increase.

  The reaction time is usually 1 hour or longer, and the upper limit is usually 10 hours or shorter, preferably 5 hours or shorter.

  In the esterification and / or transesterification reaction step and the polycondensation reaction step, the reaction is promoted by using a catalyst. As the catalyst, a titanium catalyst is preferably used.

  Specific examples of the titanium catalyst in the present invention include inorganic titanium compounds such as titanium oxide and titanium tetrachloride, titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate, and tetrabutyl titanate, titanium phenolates such as tetraphenyl titanate, and the like. Can be mentioned. Among these, tetraalkyl titanate is preferable, and among them, tetrabutyl titanate is preferable.

  A titanium compound having a chelate ligand can also be used. For example, titanium tetraacetylacetonate, titanium diisopropoxybis (acetylacetonate), titanium diisopropoxybis (ethylacetoacetate), titanium dibutoxybis (acetylacetonate), titanium lactate, titanium lactate ammonium salt, titanium di 2-ethylhexoxybis (2-ethyl-3-hydroxyhexoxide), titanium triisopropoxy (triethanolaminate), titanium diisopropoxybis (triethanolaminate), titanium tributoxy (triethanolamido) Nate) titanium dibutoxybis (triethanolaminate) and the like. Of these, titanium tetraacetylacetonate, titanium diisopropoxybis (acetylacetonate), titanium lactate, and titanium diisopropoxybis (triethanolaminate) are particularly preferable.

  When the esterification reaction and / or transesterification reaction is performed in the presence of a titanium catalyst, a catalyst may be further added before or during the polycondensation reaction after the esterification reaction and / or transesterification reaction. Is possible.

  Even in such a case, the lower limit of the titanium content in the finally obtained polybutylene terephthalate copolymer is usually 10 wtppm or more, preferably 15 wtppm or more, more preferably 20 wtppm or more, particularly preferably 25 wtppm as a titanium atom equivalent amount. As described above, most preferably 30 wtppm or more, and the upper limit is usually 150 wtppm or less, preferably 100 wtppm or less, more preferably 80 wtppm or less, particularly preferably 60 wtppm or less, and most preferably 50 wtppm or less. When the titanium content exceeds the above upper limit, the color tone of the polybutylene terephthalate copolymer obtained, the hydrolysis resistance tends to deteriorate, and the foreign matter derived from the deactivated substance of the titanium catalyst tends to increase, When the amount is less than the lower limit, the reactivity tends to decrease, and the esterification reaction and / or transesterification reaction and the polycondensation time tend to be delayed.

In the production of the polybutylene terephthalate copolymer, in addition to the titanium catalyst, a catalyst known per se, such as a tin catalyst, may be used in combination. Tin catalysts are usually used as tin compounds. Specific examples thereof include dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditin oxide, cyclohexahexylditin oxide, didodecyltin oxide, and triethyltin hydroxide. , Triphenyltin hydroxide, triisobutyltin acetate, dibutyltin diacetate, diphenyltin dilaurate, monobutyltin trichloride, tributyltin chloride, dibutyltin sulfide, butylhydroxytin oxide, methylstannic acid, ethylstannic acid, butylstannic acid Is mentioned.
However, since tin deteriorates the color tone of the polybutylene terephthalate copolymer, the amount added is usually 200 wtppm or less, preferably 100 wtppm or less, more preferably 10 wtppm as the tin atom equivalent amount in the obtained polybutylene terephthalate copolymer. Most preferably, it is not added.

In the present invention, in addition to the titanium catalyst, a compound of at least one metal selected from metals of Group 1 and 2 of the periodic table can be added as a metal atom.
In this case, the amount of the compound of at least one metal selected from Group 1 and Group 2 metals of the periodic table in the resulting polybutylene terephthalate copolymer is usually 0.1 wtppm or more as the metal atom equivalent amount. , Preferably 0.5 wtppm or more, more preferably 1 wtppm or more, and particularly preferably 3 wtppm or more. The upper limit is usually 100 wtppm or less, preferably 60 wtppm or less, more preferably 40 wtppm or less, and particularly preferably 30 wtppm or less. If the content of these metals exceeds the above upper limit, the polycondensation reaction rate tends to decrease as the polycondensation reaction proceeds, and the color tone and hydrolysis resistance of the resulting polybutylene terephthalate copolymer may deteriorate. On the other hand, if the amount is less than the above lower limit, the effect tends to be difficult to obtain. In addition, said value points out the total amount, when multiple metal seed | species is contained.

  Specific examples of the above-mentioned periodic table Group 1 metal compounds include various compounds of lithium, sodium, potassium, rubidium, and cesium. Specific examples of the compound of Group 2 metal of the periodic table include various compounds of beryllium, magnesium, calcium, strontium, and barium. Of these, lithium, sodium, potassium, magnesium, and calcium compounds are preferred from the viewpoints of handling and availability, and catalytic effects, magnesium or lithium compounds having excellent catalytic effects are more preferred, and magnesium compounds are particularly preferred. Specific examples of the magnesium compound include magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, magnesium hydrogen phosphate, and the like. Of these, magnesium acetate is preferred.

  The addition position to the reaction system of at least one metal selected from Group 1 and Group 2 metals in the periodic table is not particularly limited as long as it is before the polycondensation reaction step, and may be added at the time of raw material charging. However, if the metal component coexists in the presence of a large amount of unreacted dicarboxylic acid, a precipitate is formed, which may cause foreign matters and impair the quality of the product. It is preferably added after the transesterification step.

  The intrinsic viscosity (IV) (dl / g) of the aromatic polyester resin produced in the present invention can be controlled by polycondensation time, polycondensation temperature, polycondensation pressure, and the like. In addition, the intrinsic viscosity can be further increased by solid phase polymerization. The intrinsic viscosity of the aromatic polyester resin is such that the lower limit is usually 0.40 dl / g or more, preferably 0.45 dl / g or more in the case of a polyethylene terephthalate copolymer, because the practically sufficient mechanical properties of the polyester resin can be obtained. , More preferably 0.50 dl / g or more, particularly preferably 0.55 dl / g or more. From the viewpoint of ease of extraction after the polycondensation reaction of the polyester resin and operability such as ease of molding, the upper limit is usually 1.20 dl / g or less, preferably 1.00 dl / g or less, more Preferably it is 0.85 dl / g or less, Most preferably, it is 0.75 dl / g or less. On the other hand, in the case of a polybutylene terephthalate copolymer, the lower limit is usually 0.50 dl / g or more, preferably 0.55 dl / g or more, more preferably 0.60 dl / g or more, particularly preferably 0.65 dl / g or more. is there. From the viewpoint of ease of extraction after the polycondensation reaction of the polyester resin and operability such as ease of molding, the upper limit is usually 1.80 dl / g or less, preferably 1.50 dl / g or less, more Preferably it is 1.10 dl / g or less, Especially preferably, it is 0.90 dl / g or less.

  The intrinsic viscosity of the aromatic polyester resin is measured by the method described in the Examples section below.

Further, a polyethylene terephthalate copolymer obtained in the present invention is a melt volume rate ^{(MVR) (cm 3 / 10min} ) is optional unless significantly impairing the effects of the present invention, is preferably 30 cm ³ / 10min about . The melt volume rate can be controlled by the addition amount of the triol component, depending on the polymerization degree of the polyester resin, the upper limit is usually at most 100 cm ³ / 10min, preferably not more than 80 cm ³ / 10min, more preferably 60cm ³ / 10min or less, particularly preferably at 50 cm ³ / 10min or less, the lower limit is usually 15cm ³ / 10min or more, preferably 20 cm ³ / 10min, more preferably 25 cm ³ / 10min, particularly preferably 30 cm ³ / 10min or more. If the melt volume rate is higher than the above upper limit, the viscosity of the molten resin may be significantly reduced, the melt tension during molding is insufficient, and depending on the molding conditions such as molding method and molding temperature, a molded body can be obtained. May not be possible. On the other hand, if the melt volume rate is lower than the above upper limit, the viscosity of the resin composition may become very high, and the extruder tends to be overloaded during the molding process. In some cases, a molded article cannot be stably obtained due to the reason such as.

  The melt volume rate of the polyethylene terephthalate copolymer is measured by the method described in the Examples section below.

Further, the polybutylene terephthalate copolymer obtained in the present invention can control the melt viscosity at a shear rate of 6080 / sec by the addition amount of a triol component, etc., and the polybutylene terephthalate copolymer at a shear rate of 6080 / sec. The melt viscosity depends on the degree of polymerization of the polyester resin, but the upper limit is usually 100 Pa / sec or less, preferably 80 Pa / sec or less, more preferably 60 Pa / sec or less, particularly preferably 40 Pa / sec or less, and the lower limit is usually 1 Pa / sec or more, preferably 3 Pa / sec or more, more preferably 5 Pa / sec or more, and particularly preferably 10 Pa / sec or more. If the melt viscosity at a shear rate of 6080 / sec is larger than the above upper limit, the viscosity of the resin composition may become very high, and an excessive load is applied to the extruder during the molding process. There is a possibility that a molded body cannot be stably obtained because of the occurrence. On the other hand, when the melt viscosity is smaller than the lower limit, the melt tension at the time of molding is insufficient, and depending on molding conditions such as the molding method and molding temperature, there is a possibility that a molded body cannot be obtained.
The melt viscosity of the polybutylene terephthalate copolymer is measured by the method described in the Examples section below.

In addition, in any stage of the production process of the aromatic polyester resin or the aromatic polyester resin obtained, various additives such as a heat stabilizer, an antioxidant, a crystal nucleating agent, and the like, as long as the characteristics are not impaired, You may add a flame retardant, an antistatic agent, a mold release agent, a ultraviolet absorber, etc.
Further, when molding the aromatic polyester resin, in addition to the above-mentioned various additives, reinforcing agents and extenders such as glass fiber, carbon fiber, titanium whisker, mica, talc, CaCO ₃ , TiO ₂ and silica are added. Can also be molded.

<Polyester resin>
The polyester resin of the present invention produced as described above contains a branched structure represented by the following formula (1) and a structural unit represented by the following formula (2) in the molecular chain. The content of the branched structure represented by 1) is more than 0 and less than 10 mol%, more preferably more than 0 and less than 10 mol%, still more preferably 0 with respect to the structural unit derived from the dicarboxylic acid component in the resin. More than 9 mol%, particularly preferably more than 0 and 5 mol% or less. Below, the ratio (mol%) with respect to the structural unit derived from the dicarboxylic acid component of the branched structure represented by Formula (1) in a polyester resin may be called "branched structure (1) molar ratio."

(In the formula (1), X represents an alkylene group having 2 to 6 carbon atoms, Y represents a direct bond, an alkylene group having 1 to 10 carbon atoms, or an aralkylene group, and Z represents a hydrogen atom or a methyl group. In formula (2), R ₁ and R ₂ are each independently an alkylene group having 2 to 12 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a cycloalkylene alkylene group having 4 to 12 carbon atoms, or carbon. An arylene group having 4 to 25 carbon atoms, an alkaliylene group having 4 to 25 carbon atoms, a heteroarylene group having 4 to 25 carbon atoms, or a heteroalkylene group having 4 to 25 carbon atoms (provided that an alkylene group, a cycloalkylene group, a cyclo alkylene group, an arylene group, alkarylene group, -O -, - S -, - SO -, - SO 2 -, - into and -CO- in group one of the linking group - OSO ₂ Representing the then may be).)

In addition, a methylenephenylene group, an ethylenephenylene group, etc. are mentioned as an aralkylene group of Y in the said Formula (1). Examples of the alkylene group for R ₁ and R ₂ include an ethylene group, a propylene group, and a butylene group. Examples of the cycloalkylene group include a cyclopentylene group and a cyclohexylene group. Examples of the cycloalkylene alkylene group include a cyclohexylene dimethylene group and a tricyclodecanylene dimethylene group. Examples of the arylene group include a phenylene group, a naphthalene group, an anthrylene group, and a biphenylene group. Examples of the alkali-ylene group include a phenylene dimethylene group, a xylylene group, a 2,2′-isopropylidenebis [(4,1-phenylene) oxy] bisethylene group, and examples of the heteroarylene group include a flangyl group. Examples of the heteroalkylene group include a furanylene methylene group. The preferred examples of X, Y, and Z are the same as those in the above formula (3), and the alkylene group of R ₁ and R ₂ is particularly preferably one having 2 to 4 carbon atoms.

  In the polyester resin of the present invention, as described above, a part of the triol component forms a cyclic ether group in the molecule and is incorporated as a terminal cyclic ether structure at the end of the molecular chain of the polyester resin.

  In the polyester resin of the present invention, the content of the terminal cyclic ether group is usually 0.01 to 1 mol%, preferably 0 in the case of aliphatic polyester, based on the structural unit derived from the dicarboxylic acid component in the polyester resin. 0.03 to 0.7 mol%, more preferably 0.05 to 0.5 mol%, and usually 10 to 50 mol%, preferably 13 of the structural units derived from the triol component incorporated in the polyester resin. -40 mol%, more preferably 15-35 mol%, particularly preferably 20-30 mol% is incorporated as a terminal cyclic ether group of the polyester resin, and the balance satisfies the branched structure (1) molar ratio. The branched structure represented by the formula (1) is preferably constituted.

  In the case of an aromatic polyester, the content of the terminal cyclic ether group is usually 0.01 to 10 mol%, preferably 0.02 to 9 mol%, based on the structural unit derived from the dicarboxylic acid component in the polyester resin. Preferably it is 0.5-8 mol%, More preferably, it is 1.0-6 mol%, Usually 10-60 mol% of the structural unit derived from the triol component taken in in the polyester resin, Preferably it is 20- 60 mol%, more preferably 30 to 60 mol%, particularly preferably 40 to 60 mol% is incorporated as a terminal cyclic ether group of the polyester resin, and the remainder satisfies the branched structure (1) molar ratio. It is preferable to constitute the branched structure represented by the above formula (1).

  Whether the structural unit derived from the triol component constitutes the branched structure represented by the formula (1) or the terminal cyclic ether group in the polyester resin can be confirmed by NMR spectrum. In the case of aliphatic polyester, the peak attributed to the methine group of the triol component that appears in the vicinity of 2.2 ppm corresponds to the branched structure represented by the formula (1), and the triol component that appears in the vicinity of 3.7 ppm. The peak attributed to the methylene group corresponds to the terminal cyclic ether group.

In the case of polyethylene terephthalate copolymer, the peak attributed to the methine group of the triol component appearing in the vicinity of 2.6 ppm in ¹ H-NMR corresponds to the branched structure (1) represented by the formula (1). And what is the peak attributed to the methine group of the triol component appearing in the vicinity of 2.8 ppm corresponds to the terminal cyclic ether group.

[Usage]
The polyester resin of the present invention is excellent in heat resistance and color tone, is excellent in hydrolysis resistance and biodegradability, and can be produced at low cost, and is therefore suitable for various film applications and injection molded product applications.

  Specific applications include injection molded products (for example, fresh food trays, fast food containers, outdoor leisure products, electrical and electronic parts, etc.), extruded products (films, sheets, fishing lines, fishing nets, vegetation nets, water retaining sheets). Etc.), hollow molded products (bottles, etc.), and agricultural films, coating materials, fertilizer coating materials, laminate films, plates, stretched sheets, monofilaments, multifilaments, non-woven fabrics, flat yarns, staples, wrinkles Shrinked fiber, striped tape, split yarn, composite fiber, blow bottle, foam, shopping bag, garbage bag, compost bag, cosmetic container, detergent container, bleach container, rope, binding material, surgical thread, sanitary cover stock Used for materials, cold box, cushion film, synthetic paper, paper laminate products, etc. It is a function.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited by a following example, unless the summary is exceeded.

  The analysis method in the present invention is shown below.

<Reduced viscosity of aliphatic polyester resin (η _sp / c)>
0.25 g of pellet-shaped polyester resin is maintained at 110 ° C. for 30 minutes at a concentration (c) of 0.5 g / dl (deciliter) using a mixed solution of phenol / tetrachloroethane (weight ratio 1/1) as a solvent. Then, using a Ubbelohde capillary viscosity tube, the relative viscosity (η _rel ) with the stock solution was measured at 30 ° C., and the specific viscosity (η _sp ) determined from this relative viscosity (η _rel ) −1. ) And concentration (c) (η _sp / c).

<Terminal acid value (AV) of aliphatic polyester resin>
After pulverizing the polyester resin in the form of pellets, the sample was dried at 60 ° C. for 30 minutes in a hot air dryer and cooled to room temperature in a desiccator. Was added and dissolved at 195 ° C. for 3 minutes while blowing dry nitrogen gas, and then 5 ml of chloroform was gradually added and cooled to room temperature. Add 1 to 2 drops of phenol red indicator to this solution, and titrate with 0.1 mol / l sodium benzyl alcohol solution of sodium hydroxide with stirring while blowing dry nitrogen gas. did. Moreover, the same operation was implemented as a blank, without adding a polyester resin sample, and the terminal acid value (AV) was computed by the following formula | equation (I).
Terminal acid value (μ equivalent / g) = (ab) × 0.1 × f / w (I)
(Where a is the amount of benzyl alcohol solution of 0.1 mol / l sodium hydroxide required for titration (μl), b is the amount of 0.1 mol / l sodium hydroxide required for titration with a blank. The amount of benzyl alcohol solution (μl), w is the amount of polyester resin sample (g), and f is the titer of 0.1 mol / l sodium hydroxide in benzyl alcohol solution.

In addition, the titer (f) of the benzyl alcohol solution of 0.1 mol / l sodium hydroxide was calculated | required with the following method.
Collect 5 ml of methanol in a test tube, add 1-2 drops of phenol red ethanol solution as an indicator, Titrate to a color change point with 0.4 ml of a 1 mol / l sodium hydroxide benzyl alcohol solution, then add 0.2 ml of a 0.1 mol / l aqueous hydrochloric acid solution with a known titer as a standard solution, and add 0. The solution was titrated with a 1 mol / l sodium hydroxide solution in benzyl alcohol to the discoloration point (the above operation was performed while blowing dry nitrogen gas), and the titer (f) was calculated by the following formula (II).
Titer (f) = f _HCl × Q _HCl / Q _NaOH (II)
(Where f _HCl is the titer of 0.1 mol / l hydrochloric acid aqueous solution, Q _HCl is the amount of 0.1 N hydrochloric acid aqueous solution collected (μl), and Q _NaOH is 0.1 mol / l sodium hydroxide. Titration (μl) of a benzyl alcohol solution.)
The lower the terminal acid value, the better the heat resistance and hydrolysis resistance of the polyester resin.

<Structural analysis of aliphatic polyester resin>
The amount of terminal vinyl groups in the polyester resin, the amount of branched structure represented by the formula (1), and the amount of terminal cyclic ether groups were determined by the following method.
(NMR measurement conditions)
^The amount of terminal vinyl groups was quantified using ¹ H-NMR. A solution obtained by dissolving 20 mg of a polyester resin in 0.6 ml of deuterated chloroform was used as a measurement sample, and a ¹ H-NMR spectrum was measured at room temperature using a Bruker BioSpin Avance 400 spectrometer. The flip angle is 45 °, the data capture time is 4 seconds, the waiting time is 6 seconds, and the number of integrations is 256. The exponential function of LB (Line Broadening) = 0.1 Hz was used for the window function, and Fourier transform processing was performed.
(Terminal vinyl group content)
The amount of the vinyl group (namely, terminal vinyl group) present at the terminal of the aliphatic polyester resin is determined by using ¹ H-NMR at the end of the aliphatic polyester resin appearing near 5.15 ppm or near 5.78 ppm. Quantified by the proton peak on the carbon atom forming the double bond present in
(Branch structure amount represented by the formula (1) and terminal cyclic ether group amount)
If (there. If hereinafter abbreviated as "HMBD") as an example of an aliphatic polyester resin with the addition of ^{2-hydroxymethyl-1,4-butanediol,} using 1 H-NMR, 2.4ppm~2. A peak obtained by dividing the succinic acid peak that appears in the vicinity of 9 ppm by the number of protons is A, and the peak attributed to the methine group of the triol component that appears in the vicinity of 2.1 ppm to 2.3 ppm is B and the vicinity of 3.7 ppm to 3.8 ppm The peak attributed to the methylene group of the triol component appearing in C is defined as C, and the branched structure amount represented by the formula (1) with respect to the structural unit derived from the dicarboxylic acid component in the polyester resin according to the following formula (V-1): The amount of terminal cyclic ether groups with respect to the structural unit derived from the dicarboxylic acid component in the polyester resin can be calculated by the following formula (V-2).
Branched structure amount (mol%) represented by the formula (1) in the aliphatic polyester resin
= B / A × 100 (V-1)
Amount of terminal cyclic ether group in aliphatic polyester resin (mol%)
= C / A × 100 (V-2)

<YI value>
The YI value is obtained by filling a pellet-shaped polyester resin into a cylindrical powder measurement cell having an inner diameter of 30 mm and a depth of 12 mm, and using a colorimetric color difference meter Color Meter ZE2000 (Nippon Denshoku Industries Co., Ltd.) It measured based on the method of JISK7105. The measurement cell was rotated by 90 degrees by the reflection method and obtained as a simple average value of values measured at four points.

<Intrinsic viscosity of aromatic polyester resin (IV)>
It calculated | required in the following way using the Ubbelohde type viscometer. That is, using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1), the polyester resin solution having a concentration of 1.0 g / dl at 30 ° C. and the number of falling seconds of the solvent alone were measured, respectively, and the following formula (III )
IV = ((1 + 4K _H η _sp ) ^0.5 −1) / (2K _H C) (III)
(Where η _sp = η / η ₀ −1, η is the polyester resin solution falling seconds, η ₀ is the solvent dropping seconds, C is the polyester resin concentration (g / dl) of the polyester resin solution, K _H was adopted .K _H 0.33 is a constant of Huggins.)

<Melt Volume Rate (MVR)>
Melt volume rate (MVR) is a numerical value that represents the fluidity of a thermoplastic resin when it is melted. A polyester resin melted in a cylinder is subjected to a specified diameter at the bottom of the cylinder under a certain temperature and load condition. by measuring the polyester resin amount extruded from the die per 10 minutes, it is a value calculated by the following formula (IV), is displayed in units of "cm 3 ^/ 10min." The polyester resin sample was subjected to measurement after heat drying at 160 ° C. for 4 hours or more, or after vacuum drying treatment at 60 ° C. for 24 hours or more.
The melt time was 6 minutes, the measurement temperature was 260 ° C., the load was 2.16 kg, and the die diameter was 2 mm.
^{MVR (cm 3 / 10min) =} (427 × L) / L ... (IV)
(Here, L is a predetermined piston movement distance (cm), t is an average value (sec) of measurement time, and “427” is an average cross-sectional area of the piston and cylinder 0.711 (cm ² ) × reference) (This is a value calculated in 600 seconds of time.)

<Introduction amount of triol in aromatic polyester resin>
The amount of triol component introduced into the polyester resin was determined by the following method.
(NMR measurement)
A polyester resin sample was dissolved in a deuterated chloroform (containing 0.05 vol% tetramethylsilane) / hexafluoroisopropanol (7/3) solution, then deuterated pyridine was added, and transferred to an NMR sample tube having an outer diameter of 5 mm. A ¹ H-NMR spectrum (proton nuclear ceramic resonance spectrum) was measured using an AVANCE 400 minute meter manufactured by the manufacturer. In order to improve baseline distortion, the huge signal of hexafluoroisopropanol detected at 5.6-6.0 ppm was attenuated by pre-saturation. The resonance frequency was 400.1 MHz, the flip angle was 45 °, the data acquisition time was 4 seconds, the pulse repetition time was 10 seconds, the number of integrations was 256 or 128, the pre-saturation time was 6 seconds, the pre-saturation power was 70 dB, and the temperature was room temperature. The standard of chemical shift was calculated by assigning a spectrum by a conventional method with a tetramethylsilane signal of 0.0 ppm.

(Triol introduction amount of polyester resin)
<Polyethylene terephthalate copolymer (aromatic polyester resin)>
Taking a polyethylene terephthalate copolymer to which 2-hydroxymethyl-1,4-butanediol (hereinafter sometimes abbreviated as “HMBD”) as an example, ¹ H-NMR is used, and 7.8 ppm to 8 The peak obtained by dividing the terephthalic acid peak appearing near 0.4 ppm by the number of protons is A, and the peak attributed to the methine group of triol appearing near 2.6 ppm is B, and the methine group of triol appearing near 2.8 ppm The amount of the branched structure represented by the above formula (1) with respect to the structural unit derived from the dicarboxylic acid component in the polyester resin by the following formulas (V-3) to (V-5) The amount of terminal cyclic ether group with respect to the structural unit derived from the dicarboxylic acid component, and the structural unit derived from the dicarboxylic acid component in the polyester resin It can be calculated triol component amount.
The amount of branched structure represented by the formula (1) in the polyester resin (mol%)
= B / A × 100 (V-3)
Amount of terminal cyclic ether group in the polyester resin (mol%)
= C / A × 100 (V-4)
Amount of triol component in the polyester resin (mol%)
= (B + C) / A × 100 (V-5)
The amount of the triol component calculated here corresponds to the ratio (mol%) of all the structural units derived from the triol component introduced into the polyester resin to the structural units derived from the dicarboxylic acid component. The branched structure represented by the formula (1) and the terminal cyclic ether group of the polyester resin are included.

<Metal content of polyester resin>
The metal content of the polyester resin was quantified by ICP (Inductively Coupled Plasma) -MS (Mass Spectrometer) method after recovering the metal in the polymer by wet ashing.

<Melt viscosity of polybutylene terephthalate copolymer>
The melt viscosity was measured using a Capillograph (Capillograph 1B) manufactured by Toyo Seiki under conditions of a temperature of 270 ° C., a shear rate of 10 to 10,000 / sec, a capillary length of 0 mm, and a capillary diameter of 1 mm. In Examples and Comparative Examples, the melt viscosity value is typically 6080 / sec.

[Production Example 1: Production of 2-hydroxymethyl-1,4-butanediol]
<Oxo reaction>
To a dried stainless steel autoclave of magnetic induction stirring type having an inner volume of 10 L, 0.57 g (2.21 mmol) of [Rh (cod) (OAc)] ₂ (acetic acid (1,5-cyclooctadiene) rhodium (II) complex) ) And 35.39 g (54.71 mmol) of tris (2,4-di-t-butylphenyl) phosphite in 1990 g of 1,4-dioxane and 4191 g (47.47 g) of 1,4-butenediol. 57 mol) was charged in a nitrogen atmosphere, and the autoclave was sealed. The temperature was raised while stirring the autoclave, and after the internal temperature of the autoclave reached 70 ° C., oxo gas (H ₂ / CO = 1/1) was maintained so that the pressure in the reactor was maintained at 10 MPa (gauge pressure). ) Was fed and the reaction was carried out for 8 hours. After completion of the reaction, the autoclave was cooled to room temperature, and after depressurization and release, the reaction solution was once taken out into another container and stored in a nitrogen atmosphere.

<Hydrogenation reaction>
600 g of a hydrogenation solid catalyst having 12% by weight of nickel supported on a silica support was packed in a stainless steel basket and fixed in the 10 L autoclave. Thereafter, the stored reaction solution was charged into an autoclave under a nitrogen atmosphere, and the storage container was further washed with 200 g of 1,4-dioxane, and the washing was also charged into the autoclave. After sealing the autoclave, the temperature was raised while stirring. After the internal temperature of the autoclave reached 80 ° C., hydrogen gas was continuously fed so that the pressure in the reactor was maintained at 8 MPa (gauge pressure). The reaction was performed for 28 hours. Since the reaction rate was slow, the temperature was 90 ° C., the reaction was performed for 23 hours, and the reaction was further performed at a temperature of 100 ° C. for 20 hours. After completion of the reaction, the autoclave was cooled to room temperature, and after depressurization and release, 7349 g of the reaction solution was taken out.

<Distillation purification>
The above reaction solution was filtered under pressure with a 0.8 μm membrane filter, and 1,4-dioxane was distilled off with an evaporator. About half of the obtained solution was transferred to a separatory funnel, and 2 L of toluene was added to separate into two phases. , [Rh (cod) (OAc)] ₂ and tris (2,4-di-t-butylphenyl) phosphite were extracted into the toluene phase. The remaining liquid was treated in the same manner to obtain 4740 g of liquid washed with toluene.
A distillation apparatus was assembled and the above solution was distilled under reduced pressure. When the oil bath was heated to 220 ° C. under a reduced pressure of 2 mmHg, a light yellow viscous liquid distilled (top temperature = 180 ° C.), and the desired 2-hydroxymethyl-1,4-butanediol was obtained. 1707 g (yield 30% based on raw material) was obtained. When the obtained purified liquid was analyzed by gas chromatography, the purity of 2-hydroxymethyl-1,4-butanediol was 98.3% in terms of area strength.

[Production Example 2: Production of catalyst]
100 parts by weight of magnesium acetate tetrahydrate was placed in a glass eggplant-shaped flask equipped with a stirrer, and 1500 parts by weight of absolute ethanol (purity 99% by weight or more) was further added. Furthermore, 130.8 parts by weight of ethyl acid phosphate (mixing weight ratio of monoester and diester was 45:55) was added and stirred at 23 ° C. After confirming that magnesium acetate was completely dissolved after 15 minutes, 529.5 parts by weight of tetra-n-butyl titanate was added. Stirring was further continued for 10 minutes to obtain a uniform mixed solution. This mixed solution was transferred to an eggplant-shaped flask and concentrated under reduced pressure by an evaporator in an oil bath at 60 ° C. After 1 hour, most of ethanol was distilled off to obtain a translucent viscous liquid. The temperature of the oil bath was further raised to 80 ° C., and further concentrated under reduced pressure of 0.65 kPa to obtain a viscous liquid. This liquid catalyst was dissolved in 1,4-butanediol to prepare a titanium atom content of 3.5% by weight. The storage stability in 1,4-butanediol was good, and the catalyst solution stored at 40 ° C. in a nitrogen atmosphere showed no formation of precipitates for at least 40 days. The catalyst solution had a pH of 6.3.

[Production of aliphatic polyester resin]
<Example 1>
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer, and a vacuum outlet, 68.3 parts by weight of succinic acid, 56.9 parts by weight of 1,4-butanediol, a polyhydric alcohol compound as raw materials As a preparation, 0.35 part by weight of 2-hydroxymethyl-1,4-butanediol produced in Production Example 1 (0.5 mol% based on succinic acid) was charged, and the system was purged with nitrogen under reduced pressure under a nitrogen atmosphere. I made it.

  Next, the temperature in the system was raised to 230 ° C. over 60 minutes with stirring, and an esterification reaction was performed at 230 ° C. for 60 minutes while distilling off generated water and tetrahydrofuran under atmospheric pressure of nitrogen. After completion of the esterification reaction, the catalyst solution produced in Production Example 2 was added to initiate the polycondensation reaction. The addition amount of the catalyst solution was an amount that would be 50 wtppm as a titanium atom conversion amount per polyester resin obtained. The polycondensation reaction was carried out under a temperature condition in which the system was maintained at 230 ° C. for 30 minutes with stirring and then heated to 250 ° C. over 30 minutes. On the other hand, the pressure was reduced to 0.13 kPa in 90 minutes from the start of polycondensation, and further reacted for 111 minutes under a reduced pressure of 0.13 kPa to obtain a polyester resin. During the polycondensation reaction under reduced pressure, the pressure reducing exhaust port of the reaction vessel was continuously heated to 130 ° C. The main volatile components distilled out from the vacuum outlet during polycondensation were water, succinic anhydride, tetrahydrofuran, a cyclic monomer of succinic acid and butanediol, and a small amount of 1,4-butanediol.

The polyester resin obtained has a reduced viscosity (η _sp / c) of 2.0 dl / g, the terminal acid value of the obtained polyester resin is 20 μeq / g, the amount of terminal vinyl groups is 3.7 μeq / g, The branched structure amount represented by the formula (1) with respect to the structural unit derived from the dicarboxylic acid component in the polyester resin is 0.38 mol%, the terminal cyclic ether group amount is 0.12 mol%, and the YI value is 2.9. there were. Table 1 shows the polycondensation time and the quality evaluation results of the obtained polyester resin.

[Example 2]
The same procedure as in Example 1 was performed except that 0.31 part by weight of 1,2,4-butanetriol (0.5 mol% based on succinic acid) was added as a triol component. Table 1 shows the polycondensation conditions and the quality evaluation results of the obtained polyester resin.

[Example 3]
The same procedure as in Example 1 was performed except that 0.14 part by weight of 2-hydroxymethyl-1,4-butanediol (0.2 mol% based on succinic acid) was added. Table 1 shows the polycondensation time and the quality evaluation results of the obtained polyester resin.

[Example 4]
The same procedure as in Example 1 was conducted except that 0.125 parts by weight of 1,2,4-butanetriol (0.2 mol% based on succinic acid) was added as a triol component. Table 1 shows the polycondensation time and the quality evaluation results of the obtained polyester resin.

[Example 5]
The same procedure as in Example 1 was conducted except that 1.39 parts by weight of 2-hydroxymethyl-1,4-butanediol (2.0 mol% relative to succinic acid) was added and the polycondensation temperature was 235 ° C. It was. Table 1 shows the polycondensation time and the quality evaluation results of the obtained polyester resin.

[Example 6]
The same procedure as in Example 1 was conducted except that 0.60 part by weight of 2-hydroxymethyl-1,4-butanediol (0.86 mol% based on succinic acid) was added and the polycondensation temperature was 235 ° C. It was. Table 1 shows the polycondensation time and the quality evaluation results of the obtained polyester resin.

[Example 7]
The same procedure as in Example 1 was carried out except that 0.28 parts by weight of 2-hydroxymethyl-1,4-butanediol (0.43 mol% based on succinic acid) was added and the polycondensation temperature was 235 ° C. It was. Table 1 shows the polycondensation time and the quality evaluation results of the obtained polyester resin.

[Comparative Example 1]
The same procedure as in Example 1 was performed except that 0.39 parts by weight of malic acid (0.50 mol% based on succinic acid) was added as a trifunctional component instead of the triol component. It was difficult. The polycondensation time is shown in Table 1. The quality evaluation of the polyester resin was not possible.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that 0.155 parts by weight of malic acid (0.20 mol% based on succinic acid) was added as a trifunctional component instead of the triol component. The terminal acid value increased, the terminal vinyl group increased, and the YI value increased. Table 1 shows the polycondensation time and the quality evaluation results of the obtained polyester resin.

[Comparative Example 3]
As in the case of Example 1, except that 0.267 parts by weight of glycerol (0.50 mol% based on succinic acid) was added as a triol component, polycondensation delay and an increase in YI value were observed. . Table 1 shows the polycondensation time and the quality evaluation results of the obtained polyester resin.

In Table 1, “2-hydroxymethyl-1,4-butanediol” is described as “HMBD”, and “1,2,4-butanetriol” is described as “1,2,4-BT”. .
In the above Examples 1 to 7, the addition amount of 2-hydroxymethyl-1,4-butanediol or 1,2,4-butanetriol to succinic acid is the total triol introduction amount introduced into the obtained polyester resin. It can be regarded as the structural unit amount derived from a component. Among these, the proportion of the terminal cyclic ether group was determined by the above-described method, and the difference from the amount of structural units derived from all triol components introduced into the polyester resin was determined as the branched structure amount (branched structure (1 ) And (molar ratio).

[Production of aromatic polyester resin]
[Example 8]
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer, a distillation pipe, and a vacuum outlet, bis (hydroxyethyl) terephthalate (hereinafter sometimes referred to as BHET) 158.8 parts by weight, Then, 0.075 parts by weight of 2-hydroxymethyl-1,4-butanediol (0.1 mol% based on BHET) was added as a triol, and then the system was placed under a nitrogen atmosphere by nitrogen-reduced pressure substitution. The system was heated to 250 ° C. with stirring, and then subjected to ester reaction at 250 ° C. for 0.5 hour to obtain an oligomer.
Subsequently, as a catalyst, germanium dioxide is used in an amount of 79.8 wtppm as a germanium atom conversion amount with respect to the obtained polyester resin, and normal phosphoric acid is used as a phosphorus atom conversion amount of 47.4 wtppm with respect to the obtained polyester resin. The amount was charged.

Next, the temperature was raised to 280 ° C. over 70 minutes, the pressure was reduced to 0.26 kPa over 30 minutes, and a polycondensation reaction was performed for 118 minutes under a reduced pressure of 0.26 kPa to obtain a polyester resin.
The polycondensation time refers to the time from the start of pressure reduction to the time when the power reaches the power at which the intrinsic viscosity (IV) of the polymer is around 0.65 (dl / g). After completion of the polycondensation reaction, the reaction system was returned to normal pressure to complete the polycondensation reaction. The obtained polyester resin was extracted as a strand from the bottom of the reaction vessel, submerged in 10 ° C water, and then the strand was cut with a cutter to obtain a pellet-like polyester resin.

The intrinsic viscosity (IV) of the obtained polyester resin was 0.65 dl / g. The polycondensation time was defined as the time from the start of pressure reduction to the end of the polycondensation reaction, and the polycondensation reaction rate was defined as the intrinsic viscosity / polycondensation reaction time. The polycondensation reaction rate was 0.26 dl / g / h. Further, MVR value of this polyester resin was 32.8 ^(cm 3 / 10min). Various analysis results are shown in Table 2.

[Example 9]
A polyester resin was obtained in the same manner as in Example 8 except that HMBD was added to 0.375 parts by weight (0.5 mol% based on BHET). Various analysis results are shown in Table 2.

[Example 10]
A polyester resin was obtained in the same manner as in Example 8 except that HMBD was added so as to be 3.75 parts by weight (5.0 mol% with respect to BHET). Various analysis results are shown in Table 2.

[Example 11]
A polyester resin was obtained in the same manner as in Example 8 except that HMBD was added so as to be 7.51 parts by weight (10.0 mol% based on BHET). Various analysis results are shown in Table 2.

[Comparative Example 4]
In Example 8, a polyester resin was obtained in the same manner as in Example 8 except that HMBD was not added. Various analysis results are shown in Table 2.

[Example 12]
In Example 8, 103.2 parts by weight of BHET, 36.2 parts by weight of terephthalic acid, and 3.75 parts by weight of HMBD as a triol component (5.0 mol% with respect to the sum of BHET and terephthalic acid) were added. A polyester resin was obtained in the same manner as in Example 8. Various analysis results are shown in Table 2.

[Comparative Example 5]
In Example 12, HMBD was not added, 103.2 parts by weight of BHET, 31.1 parts by weight of terephthalic acid, and 6.5 parts by weight of trimellitic acid (5.0% relative to the sum of BHET and terephthalic acid) Except for addition, the polycondensation reaction was accompanied by an abrupt torque change and became difficult to control. Moreover, the intrinsic viscosity of the obtained polyester resin could not be measured due to gelation. Various analysis results are shown in Table 2.
Incidentally, from the content ^{1 H-NMR} of the constitutional unit derived from trimellitic acid in the obtained polyester resin has been determined to be 3.9 mol% with respect to constitutional unit derived from dicarboxylic acid component, there is a gel Therefore, there is concern that some signals are not observed.

[Comparative Example 6]
A polyester resin was prepared in the same manner as in Example 12 except that HMBD was not added and 0.42 parts by weight of trimethylolpropane (0.5 mol% based on the sum of BHET and terephthalic acid) was added. Got. Various analysis results are shown in Table 2. The content of the structural unit derived from trimethylolpropane in the polyester resin was determined to be 0.4 mol% with respect to the structural unit derived from the dicarboxylic acid component of the polyester resin from ¹ H-NMR.

[Comparative Example 7]
Example 12 was carried out in the same manner as in Example 12 except that HMBD was not added and 1.68 parts by weight of trimethylolpropane (2.0 mol% based on the sum of BHET and terephthalic acid) was added. The polycondensation reaction was accompanied by a rapid torque change and became difficult to control. Moreover, the intrinsic viscosity of the obtained polyester resin could not be measured due to gelation. Various analysis results are shown in Table 2.
The content of the constitutional unit derived from trimethylol propane in the obtained polyester resin is from ^{1 H-NMR,} it was found to be 1.5% by mole relative to the constitutional unit derived from the dicarboxylic acid component of the polyester resin Because of the presence of the gel, there is a concern that some signals are not observed.

[Reference Example 1]
The same procedure as in Example 12 was carried out except that HMBD was not added and 0.64 parts by weight of tetrahydro-3-furanmethanol (1.0 mol% based on the sum of BHET and terephthalic acid) was added. A polyester resin was obtained. Various analysis results are shown in Table 2.
In addition, the content of THFM of the structural unit derived from tetrahydro-3-furanmethanol of the obtained polyester resin is 0.2 mol% with respect to the structural unit derived from the dicarboxylic acid component of the polyester resin from ¹ H-NMR. I was asked.

  In Table 2 below, “2-hydroxymethyl-1,4-butanediol” is described as “HMBD”, “trimellitic acid” is described as “TMA”, and “trimethylolpropane” is expressed as “TMP”. And “tetrahydro-3-furanmethanol” is described as “THFM”.

[Example 13]
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer, a distillation pipe, and a vacuum outlet, 131 parts by weight of dimethyl terephthalate (manufactured by Teijin), 73 parts by weight of 1,4-butanediol and a catalyst 0.59 parts by weight of a 1,4-butanediol solution in which 6% by weight of tetrabutyl titanate was dissolved in advance (33 ppm by weight as titanium atoms with respect to the resulting polybutylene terephthalate copolymer) was added, and 2-hydroxymethyl-1 , 4-butanetriol (3.00 parts by weight (3.3 mol% with respect to 1 mol of all dicarboxylic acid components in the resulting polyester resin)) was charged, and the system was placed in a nitrogen atmosphere by nitrogen-reduced pressure substitution.
The system was heated to 150 ° C. with stirring, and then reacted for 180 minutes while distilling off the methanol produced by the transesterification reaction while raising the temperature to 210 ° C. to obtain an oligomer.
Subsequently, 1.08 parts by weight of a 1,4-butanediol solution in which 6% by weight of tetra-n-butyl titanate was dissolved in advance as a catalyst (61 ppm by weight as titanium atoms with respect to the obtained polybutylene terephthalate copolymer) was charged. 1,4-butanediol solution in which 10% by weight of magnesium acetate tetrahydrate had been dissolved in advance was charged in an amount of 0.63 parts by weight (48 ppm by weight as Mg atoms with respect to the resulting polybutylene terephthalate copolymer).
Next, the temperature was raised to 240 ° C. over 60 minutes and held. On the other hand, the pressure was controlled to be 0.4 kPa over 90 minutes from the start of polymerization, and a predetermined torque was reached in 90 minutes from the start of polymerization to obtain a polyester resin.
The resulting polyester resin had an intrinsic viscosity (IV) of 0.70 dl / g and a terminal acid value of 18 μeq / g. The melt viscosity was 16 Pa · sec at a shear rate of 6080 (/ sec).

[Comparative Example 8]
The same procedure as in Example 13 was performed except that 2-hydroxymethyl-1,4-butanetriol was not used. A predetermined torque was reached in 190 minutes from the start of polymerization to obtain a polyester resin. The obtained polyester resin had an intrinsic viscosity (IV) of 0.70 dl / g and a terminal acid value of 22 μeq / g. The melt viscosity was 28 Pa · sec at a shear rate of 6080 (/ sec).

Claims (13)

A polyester resin containing a structural unit derived from a dicarboxylic acid component, a diol component, and a triol component in a molecular chain, the branched structure represented by the following formula (1) and the structural unit represented by the following formula (2): Polyester resin contained in the molecular chain.

(In the formula (1), X represents an alkylene group having 2 to 6 carbon atoms, Y represents a direct bond, an alkylene group having 1 to 10 carbon atoms, or an aralkylene group, and Z represents a hydrogen atom or a methyl group. In formula (2), R ₁ and R ₂ are each independently an alkylene group having 2 to 12 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a cycloalkylene alkylene group having 4 to 12 carbon atoms, or carbon. An arylene group having 4 to 25 carbon atoms, a heteroarylene group having 4 to 25 carbon atoms, or two or more of these alkylene group, cycloalkylene group, cycloalkylene alkylene group, arylene group, and heteroarylene group are directly or —O—, (It represents a divalent group formed by connecting through any one of —S—, —SO—, —SO ₂ —, —OSO ₂ — and —CO—).   The polyester resin according to claim 1, wherein in the formula (1), Y is a direct bond or a methylene group.   The polyester resin according to claim 2, wherein, in the formula (1), X is an ethylene group, Y is a methylene group, and Z is a hydrogen atom.   The content of the branched structure represented by the formula (1) is more than 0 and 10 mol% or less with respect to the structural unit derived from the dicarboxylic acid component in the resin. The polyester resin as described in.   The dicarboxylic acid component is an aromatic dicarboxylic acid and / or an ester-forming derivative thereof, and the diol component is ethylene glycol and / or 1,4-butanediol. Polyester resin.   The polyester resin according to any one of claims 1 to 4, wherein the dicarboxylic acid component is an aliphatic dicarboxylic acid and / or an ester-forming derivative thereof, and the diol component is 1,4-butanediol.   The polyester resin according to claim 6, wherein the dicarboxylic acid component is succinic acid and / or adipic acid. A polyester resin is produced through an esterification step in which an esterification reaction or a transesterification reaction is performed using a dicarboxylic acid component and a diol component, and a melt polycondensation reaction step in which a polycondensation reaction is performed on an oligomer obtained by the esterification step. In the method to do, the manufacturing method of the polyester resin which adds the triol compound represented by following formula (3) by arbitrary processes.

(However, in Formula (3), X represents a C2-C6 alkylene group, Y represents a direct bond, a C1-C10 alkylene group, or an aralkylene group, and Z represents a hydrogen atom or a methyl group. Represents.)   In the said Formula (3), Y is a direct bond or a methylene group, The manufacturing method of the polyester resin of Claim 8.   In the said Formula (3), X is an ethylene group, Y is a methylene group, Z is a hydrogen atom, The manufacturing method of the polyester resin of Claim 9.   The polyester according to any one of claims 8 to 10, wherein the dicarboxylic acid component is an aromatic dicarboxylic acid and / or an ester-forming derivative thereof, and the diol component is ethylene glycol and / or 1,4-butanediol. Manufacturing method of resin.   The method for producing a polyester resin according to any one of claims 8 to 10, wherein the dicarboxylic acid component is an aliphatic dicarboxylic acid and / or an ester-forming derivative thereof, and the diol component is 1,4-butanediol. .   The method for producing a polyester resin according to claim 12, wherein the dicarboxylic acid component is succinic acid and / or adipic acid.