JP2008045117A - Method for producing aliphatic polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an industrially advantageous and efficient method for producing an aliphatic polyester having a high degree of polymerization and excellent in thermal stability. <P>SOLUTION: This method for producing the polyester having an aliphatic diol unit and an aliphatic dicarboxylic acid unit is provided by using a catalyst prepared in advance by mixing a titanium compound, an alkaline earth metal compound and a phosphorus compound, as the catalyst. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing an aliphatic polyester. Specifically, the present invention relates to a method for producing an environmentally-friendly high-polymerization aliphatic polyester having excellent moldability, thermal stability and tensile properties by injection molding, hollow molding and extrusion molding, good color tone, and excellent biodegradability. Is.

  The aliphatic polyester having biodegradability has been applied to fibers, molded articles, films, sheets, and the like as a resin that avoids environmental burdens more than ever because of increasing awareness of environmental problems. For example, polybutylene succinate and / or polybutylene adipinate having biodegradability has been developed as an alternative polymer for polyethylene because it has similar mechanical properties to polyethylene.

  As an economically advantageous polyester production method, a low ester ester polymer is produced by a direct esterification reaction between a dicarboxylic acid and a diol in the presence of a catalyst or an ester exchange reaction between an alkyl ester of a dicarboxylic acid and a diol. Thereafter, a method for producing a polyester having a high degree of polymerization by distilling off a diol produced while performing a transesterification reaction under heating and reduced pressure from a reaction system has been known for a long time.

  However, since the thermal stability of aliphatic polyesters is generally low and the molecular weight is lowered due to thermal decomposition during the polymerization reaction, polyesters with a high degree of polymerization having practically sufficient strength can be obtained by conventional polyester production methods. There wasn't. It has been proposed that the polymer terminal (hydroxyl group or carboxyl group) concentration, particularly the residual carboxyl group, has a significant adverse effect on the thermal stability of the polymer (see, for example, Patent Document 1). From such a background, various devices have been devised in the manufacturing method.

  For example, a method has been proposed in which melt polymerization is performed using an organoalkoxy metal compound such as tetrabutyl titanate as a catalyst, and a polymer chain length is increased by adding diisocyanate or diphenyl carbonate as a chain extender to increase the melt viscosity of the polymer. (For example, refer to Patent Document 2). Since the method of adding these chain extenders can easily increase the molecular weight of the polyester, it is considered to be an effective method for producing an aliphatic polyester at first glance. In addition to the fact that the resulting polyester is slightly reduced in crystallinity and melting point, the biodegradability tends to decrease because the molecule contains a urethane bond. There is a problem. In addition, from the viewpoint of use as a biodegradable resin, diisocyanate has a problem in that a highly toxic diamine is produced during the decomposition process and may accumulate in the soil, and diphenyl carbonate is also a highly toxic byproduct. The problem remains that phenol and unreacted diphenyl carbonate remain in the polyester.

As a technique for improving the polymerization reaction using an organic titanium catalyst, a technique in which a magnesium compound coexists with a titanium catalyst has been proposed, but not only a polyester having a practically sufficient degree of polymerization cannot be obtained. Increasing the concentration tends to promote thermal decomposition of the polyester (see, for example, Patent Document 3).
Titanium compounds are a catalyst system that attracts attention because they are inexpensive and have no concerns about safety and hygiene. However, the method for producing polyester using a titanium compound as a catalyst has a characteristic yellowish color, There are drawbacks such as poor stability and insufficient polymerization rate. Further, if the charge molar ratio of the diol component to the dicarboxylic acid component of the raw material is increased to increase the polymerization rate, the color tone tends to deteriorate, so that the process tends to be restricted by the raw material charge molar ratio. As a method for improving the color tone, a method in which a phosphorus compound is allowed to coexist in a titanium-based catalyst as a coloring inhibitor has been proposed (for example, see Patent Document 4). However, as is apparent from the description that the amount of the phosphorus compound to be added increases the time required for polymerization when the addition amount is large, the phosphorus compound has a drawback of suppressing the catalytic activity of the titanium catalyst.

Furthermore, as a technique for improving the polymerization activity, a catalyst system combining a titanium catalyst and a hydrogen-containing magnesium phosphate has been proposed (see, for example, Patent Document 5).
However, any system in which a magnesium compound or a phosphorus compound coexists with the above titanium-based catalyst requires a plurality of independent catalyst addition apparatuses, and the introduction of the catalyst becomes complicated and has a drawback that it is difficult to control. In particular, when an organic titanium catalyst is used as the titanium compound, the organic titanium catalyst usually has a property of being easily hydrolyzed, so there are restrictions on the storage method of the catalyst at high temperatures and the introduction method of the catalyst at the time of polymerization. Part of the catalyst is deactivated by water that is received or generated by the condensation polymerization reaction, so that there is a problem that control of the catalyst activity is difficult and reproducibility of production is difficult to take. For example, tetrabutyl titanate, which is a typical catalyst, is not only a dangerous substance having a flash point of 53 ° C., but also heat stability, hydrolyzability, Known as a compound with poor stability. Therefore, when using a general organic titanium catalyst, it is necessary to devise a catalyst storage method so that a part of the catalyst component does not precipitate as a precipitate during the storage.
JP-A-7-53700 JP-A-4-189822 JP 2001-98065 A JP-A-7-242742 JP 2002-356548 A

  The present invention has been made in view of the above circumstances, and its purpose is to improve the activity and storage stability of the catalyst, so that there is no severe restriction on the molar ratio of raw materials, the reaction rate in polymerization is high, and chain extension. Another object of the present invention is to provide a polyester having a high degree of polymerization having sufficient tensile properties and excellent color tone by an industrially advantageous method without using an agent or the like.

As a result of examining the polycondensation catalyst in order to achieve the above object, the present inventors have found that a catalyst in which a titanium compound, an alkaline earth metal compound and a phosphorus compound are mixed in advance has a high concentration of catalytic active components, and It has been found that the polyester polymerization catalyst is industrially advantageous because of its excellent long-term storage stability.
That is, the gist of the present invention is that a catalyst in which a titanium compound, an alkaline earth metal compound and a phosphorus compound are mixed in advance is used as a catalyst when producing a polyester having an aliphatic diol unit and an aliphatic dicarboxylic acid unit. A method for producing an aliphatic polyester.

  According to the production method of the present invention, it is possible to easily produce an aliphatic polyester having a high polymerization degree, which has a high polymerization reaction rate and has sufficient tensile properties and excellent color tone without using a chain extender or the like. . Further, according to the production method of the present invention, an aliphatic polyester having a high degree of polymerization can be produced without being severely restricted by the raw material charge molar ratio. Further, the polyester obtained by the production method of the present invention reduces the thermal decomposition and thermal degradation of the polyester due to the residual catalyst in the polyester, so that the moldability, thermal stability and tension by injection molding, hollow molding and extrusion molding are reduced. Excellent mechanical properties such as properties.

Hereinafter, the present invention will be described in detail.
<Catalyst>
In the present invention, a catalyst in which a titanium compound, an alkaline earth metal compound and a phosphorus compound are mixed in advance is used as a production catalyst for the aliphatic polyester.
The production method of the polyester polycondensation catalyst of the present invention will be described below. The content of titanium atoms, alkaline earth metal atoms and phosphorus atoms in the catalyst used in the present invention is the same as the content of titanium atoms. When T (molar basis), the alkaline earth metal content is M (molar basis), and 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 0.7, and the upper limit is usually 5.5, preferably 4.0, more preferably 3.0, particularly preferably 1. .5, 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 Is 3.0, more preferably 2.0, particularly preferably 1.5, still more preferably 1.2, and most preferably 1.1. If it 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 are less likely 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 hardly increases.

The catalyst in the present invention is produced by mixing a titanium compound, an alkaline earth metal compound, and an acidic phosphate ester compound. When mixing the catalyst components, a solvent is usually used. As the solvent, a titanium compound, an alkaline earth metal compound, and an acidic phosphate compound may be used as 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. To elaborate on this particularly preferred production method,
(i) Step of mixing, dissolving, and reacting alcohol, titanium compound, alkali metal compound and acidic phosphate compound
(ii) A step of concentrating by distilling off alcohol etc. from the reaction solution obtained in step (i) and further proceeding with the reaction to obtain a viscous liquid catalyst, solid catalyst, or a mixture thereof. Manufactured by. At this time, it is considered that the alcohol used does not participate in the reaction but only serves as a solvent.

  The difference between the viscous liquid catalyst, the solid catalyst, or a mixture thereof and the resulting catalyst is due to the degree of concentration. The catalyst obtained in step (ii) can be easily recovered after it is dissolved or dissolved in glycol such as 1,4-butanediol or ethylene glycol. In addition, what is distilled off at the time of concentration is an alcohol, an organic acid, or the like by-produced by a reaction between an alcohol used as a solvent, a titanium compound, an alkaline earth metal compound, and an acidic phosphate compound.

The weight of the catalyst thus obtained is always less than the total weight of the raw materials excluding the alcohol used as the solvent. The weight W ₁ of the resulting catalyst and the sum W ₀ of the weights of the titanium compound, alkaline earth metal compound, and acidic phosphate compound used for mixing, that is, mixed with alcohol in the step (i) above. The ratio W ₁ / W ₀ is usually 0.45 or more and 0.85 or less. This ratio varies depending on the type of raw material compound used and the composition ratio.

  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 glycol. Among these, monohydric alcohols are preferably used from the viewpoint of solubility of the compound and ease of handling. These alcohols may be used alone or in combination of two or more. In particular, ethanol is preferred because the titanium compound, alkaline earth metal compound, and acidic phosphate compound have high solubility and have a low boiling point when the reaction solution is concentrated and are easy to remove.

  Examples of titanium compounds include tetraalkoxy titanates such as tetra-n-propyl titanate, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, tetra-t-butyl titanate; acetyl- Examples include tri-i-propyl titanate; titanium acetate and the like, among which tetra-i-propyl titanate and tetra-n-butyl titanate, which are easily available and easy to handle, are preferable, and tetra-n-butyl titanate is particularly preferable. These titanium compounds may be used individually by 1 type, and may use 2 or more types together.

  As the alkaline earth metal compound, an organic acid salt of alkaline earth metal and / or a hydrate thereof is preferably used. Among them, preferred compounds include organic acid salts such as magnesium and calcium, and / or hydrates thereof. Magnesium compounds are preferred from the viewpoint of catalytic activity. Examples of the magnesium compound include organic acid salts such as magnesium acetate and magnesium butyrate. In particular, magnesium acetate and / or a hydrate thereof are preferable because of high solubility in alcohol and easy preparation of a catalyst. These alkaline earth metal compounds may be used alone or in combination of two or more. Also, different metal compounds such as magnesium compounds and calcium compounds can be used in combination.

  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.

(Wherein R, R ′ and R ″ each represent an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group, an aryl group or a 2-hydroxyethyl group. In formula (I), R and R ′ are the same. It may or may not be.)

  Specific examples of such acidic phosphoric acid 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.

  In addition, although there exist monoester body (II) and diester body (I) in an acidic phosphoric ester compound, since the catalyst which shows high catalyst activity is obtained, a monoester body or a monoester body and a diester body It is preferable to use a mixture. The mixing weight ratio of monoester and diester (monoester: diester) is preferably 80 or less: 20 or more, more preferably 70 or less: 30 or more, and particularly preferably 60 or less: 40 or more. Also, it is preferably 20 or more and 80 or less, more preferably 30 or more and 70 or less, and particularly preferably 40 or more and 60 or less.

  In the production of polyester, when a plurality of catalyst components are used as a catalyst, conventionally, a method of separately introducing each catalyst component into a reactor from a plurality of introduction locations has been taken. On the other hand, in the present invention, a catalyst compound prepared by mixing a titanium compound, an alkaline earth metal compound, and a phosphorus compound before being introduced into the reactor is introduced into the reactor for use. This eliminates the need for a plurality of independent catalyst addition apparatuses in the production process, which can consolidate the introduction points of the catalyst into the reactor, and does not require complicated control of the catalyst component ratio during catalyst introduction. Therefore, it becomes an industrially advantageous process.

In the present invention, a conventionally known apparatus can be used for mixing, dissolving, and reacting the titanium compound, alkaline earth metal, and phosphorus compound, and the process may be performed in a single reaction tank or a plurality of reaction tanks. May be used. The reaction vessel is preferably provided with a stirring and mixing device in order to cause a uniform reaction.
The reaction temperature is usually 0 ° C. or higher, preferably 10 ° C. or higher, more preferably 20 ° C. or higher, and usually 100 ° C. or lower, preferably 80 ° C. or lower, more preferably 50 ° C. or lower. After the reaction, the prepared solvent and the like are distilled off at 150 ° C. or lower with a conventionally known concentrating device as necessary to obtain a liquid or solid homogeneous catalyst.

The catalyst of the present invention is preferably stored in a closed container, and for the reason that deterioration of the catalyst is suppressed, in particular, after replacement inside the container with an inert gas such as nitrogen at room temperature, storage in a sealed state is possible. preferable. Under such an inert gas atmosphere, storage for one year or more is possible.
The catalyst of the present invention can be handled as a viscous liquid before being isolated as a solid catalyst, and can be used as it is. In order to reduce the viscosity of such a viscous liquid and make it easier to handle, the catalyst of the present invention is dissolved and diluted with glycol which is a polyester resin raw material such as 1,4-butanediol or ethylene glycol. And can be stored as a catalyst solution.

The titanium atom concentration after diluting such a viscous liquid catalyst with a polyester resin raw material glycol such as 1,4-butanediol and ethylene glycol has a lower limit of usually 10,000 ppm, preferably 20,000 ppm, and an upper limit of Usually, it is 50,000 ppm, preferably 40,000 ppm. If the concentration of titanium atoms during storage is below the above upper limit, it will be difficult for the catalyst to deteriorate and aggregates, while on the other hand, more than the above lower limit and the amount of diluent used will be small, and the storage equipment may be small. The liquid catalyst or catalyst solution of the present invention can also be handled in the air, but in the case of long-term storage for a few months or more, it is inactive because the deterioration of the catalyst can be suppressed. It is preferable to store in a gas atmosphere.

In the present invention, the pH of the 1,4-butanediol or ethylene glycol solution containing the catalyst has an upper limit of usually 7, preferably 6.7, more preferably 6.5, and a lower limit of usually 3, preferably 4, more preferably 5.0. When the pH is below the above upper limit, the metal is difficult to precipitate, and when the pH is above the above lower limit, the catalyst is unlikely to change into a gel state over time, and the apparatus is less likely to corrode. Therefore, a phosphorous compound that exhibits acidity in a 1,4-butanediol or ethylene glycol solution as necessary so as to be in such a pH range, particularly the above-mentioned acidic phosphate compound, alkaline earth metal compound, etc. It is preferable to prepare using

  In addition, the catalyst of the present invention contains a small amount of water for the reason that the deterioration of the catalyst is suppressed and the storage stability is improved when it needs to be dissolved in 1,4-butanediol or ethylene glycol and stored. It is preferable. In this case, the preferred water content is preferably 10% by weight or less, more preferably 5% by weight or less, particularly 2.5% by weight as the weight concentration with respect to the total ethylene glycol or 1,4-butanediol solution containing the catalyst. % Or less is preferable. Moreover, 0.01 weight% or more is preferable, More preferably, it is 0.1 weight% or more, Especially 0.5 weight% or more is preferable. The reason why a homogeneous catalyst solution that is stable for a long period of time is obtained in this manner is that a ternary of titanium / alkaline earth metal / phosphorus is obtained by mixing an acidic phosphate ester compound, an alkaline earth metal compound, and a titanium compound. A system complex is formed, which is considered stable in the glycol solution.

  In the present invention, when the catalyst is stored in the catalyst tank in the polymerization system, it can be stored in a solid state. However, as described above, the lower limit of the titanium atom concentration of the catalyst solution is usually 10,000 ppm, preferably It may be dissolved and stored in 1,4-butanediol or ethylene glycol so that the upper limit is 20,000 ppm, usually 50,000 ppm, preferably 40,000 ppm. When the catalyst is used, it may be further diluted with a polyester resin raw material glycol such as 1,4-butanediol and ethylene glycol. The lower limit of the titanium atom concentration in the catalyst solution when using the catalyst is usually 300 ppm, preferably 400 ppm, more preferably 500 ppm, and the upper limit is usually 17,000 ppm, preferably 15,000 ppm, more preferably 12,000 ppm, particularly preferably. Is 10,000 ppm. When the titanium atom concentration is less than the above upper limit, precipitation of catalyst degradation products and agglomerates is difficult to occur, the production becomes stable, and the risk that the precipitates are mixed as foreign substances in the product tends to be low, On the other hand, if the amount is not less than the above lower limit, the amount of the diluent used is small, which is economically advantageous and the polymerization reaction is hardly delayed.

The solid catalyst or catalyst solution of the present invention can be handled in air in the catalyst tank, but is preferably stored in an inert gas atmosphere. In the catalyst for polycondensation of the present invention, the pH of 1,4-butanediol or ethylene glycol solution is usually 7, preferably 6.7, more preferably 6.5, Is stored at 3, preferably 4, and more preferably 5.0. If the pH is below the above upper limit, the metal is difficult to precipitate, and if the pH is above the above lower limit, the catalyst is unlikely to change to a gel state over time, and the corrosion of the apparatus is less likely to occur, resulting in a longer catalyst. Even when used in a reaction vessel in a time polymerization facility, there is a low risk that foreign matter will be generated in the product and quality will be impaired. Therefore, in order to be in such a pH range, in the 1,4-butanediol or ethylene glycol solution in the catalyst tank, if necessary, a phosphorous compound exhibiting acidity, particularly the above acidic phosphate compound or alkaline earth. It is preferable to prepare using a similar metal compound.
Further, the preferred water content is preferably 10% by weight or less, more preferably 5% by weight or less, particularly 2.5% by weight as the weight concentration of the polycondensation catalyst with respect to the total 1,4-butanediol or ethylene glycol solution. % Or less is preferable. Moreover, 0.01 weight% or more is preferable, More preferably, it is 0.1 weight% or more, Especially 0.5 weight% or more is preferable.

In the present invention, when a catalyst obtained by combining a known layered silicate described in “Clay Mineralogy” Asakura Shoten (1995) by Haruo Shiramizu with the above catalyst may be used, the polymerization rate may be improved. Therefore, such a catalyst system is also preferably used.
Specific examples of layered silicates include kaolin groups such as dickite, nacrite, kaolinite, anorokite, metahalloysite, halloysite; serpentine groups such as chrysotile, lizardite, antigolite; montmorillonite, zauconite, beidellite, Smectites such as nontronite, saponite, hectorite, stevensite, etc .; vermiculites such as vermiculite; mica such as mica, illite, sericite, marine stone; attapulgite, sepiolite, palygorskite, bentonite, pyrophyllite, talc And chlorite group.

  Also, mineral acids such as hydrochloric acid and sulfuric acid or salts thereof, sulfuric acid esters such as dimethyl sulfate, diethyl sulfate, and ethyl sulfate, organic sulfonic acids such as methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, phosphoric acid, Phosphorous acid, pyrophosphorous acid, phosphorous acid, hypophosphoric acid, pyrophosphoric acid, triphosphoric acid, metaphosphoric acid, peroxophosphoric acid, polyphosphoric acid and other inorganic phosphoric acid, ammonium hydrogen phosphate, magnesium hydrogen phosphate, calcium hydrogen phosphate, hydrogen polyphosphate Inorganic hydrogen phosphates such as ammonium, magnesium hydrogen phosphate, calcium hydrogen phosphate, etc., organic phosphinic acids such as phenylphosphinic acid, benzylphosphinic acid, methylphosphinic acid, n-butylphosphinic acid, cyclohexylphosphinic acid, diphenylphosphinic acid, And phenylphosphonic acid, benzyl Suhon acid, methylphosphonic acid, n- butylphosphonic acid, also catalyst systems using organic phosphonic acids such as cyclohexyl phosphonic acid as co-catalyst can be used.

  Below, ethanol as an alcohol that works as a solvent for catalyst preparation, raw material compound for catalyst production, tetra-n-butyl titanate as a titanium compound, magnesium acetate tetrahydrate as a magnesium compound, acidic phosphate compound The method for producing the catalyst of the present invention will be described more specifically by taking as an example the case of using ethyl acid phosphate (mixing weight ratio of monoester and diester is 45:55).

In step (i), ethanol and a raw material compound are charged into a reaction vessel equipped with a raw material inlet, a stirrer, and the like, and are stirred and mixed for reaction. The reaction is carried out under mild conditions. For example, under normal pressure, it is usually 10 ° C. or higher, preferably 20 ° C. or higher, usually 80 ° C. or lower, preferably 50 ° C. or lower. (Step (i)). After visually confirming that the reaction solution has become transparent, the solvent is distilled off under reduced pressure to concentrate the reaction solution (step (ii)). Concentration is usually carried out at a temperature of 150 ° C. or less, preferably 120 ° C. or less, particularly preferably 100 ° C. or less, using a general distillation apparatus, evaporator, conical dryer, spray dryer, centrifugal thin film concentrator, cracks dryer or the like. The In addition, it can be carried out by adding a decompression equipment equipped with a distillation pipe to the reactor of step (i) as long as a viscous liquid is obtained without performing high concentration. The device can be simplified.

  In the initial stage of the concentration step (ii), the alcohol that mainly functions as a solvent is distilled off. In the latter stage of concentration, acetic acid derived from magnesium acetate, water, and butanol derived from tetra-n-butyl titanate are distilled. In this way, in the state where 90% by weight or more of the alcohol that worked as a solvent has been distilled off, a viscous liquid is formed, and this viscous liquid catalyst gradually becomes a dense liquid as the concentration proceeds. It becomes a mixture with the solid (powder) catalyst produced on the surface, and becomes a solid catalyst as the concentration further proceeds.

In the solid catalyst obtained in such a concentration step, a mass reduction of 30 to 50% by weight is usually observed with respect to the total weight of the mixed raw material compounds (that is, W ₁ / W ₀ = 0. The reduction ratio of the weight of the obtained catalyst with respect to the total weight of the mixed raw material compounds of 5 to 0.7 or less is sometimes referred to as “weight reduction ratio during production”.
This solid catalyst mainly contains 1 to 20% by weight of butanol and may contain 0.8 to 1.5 moles of acetic acid (acetate) coordinated to magnesium with respect to the number of moles of magnesium metal. . Thus, the highly concentrated solid catalyst has extremely advantageous characteristics with respect to transportability and storage stability. In addition, the obtained solid catalyst can be handled in the air, does not show adhesion to the reactor and glass products, and is soluble in water. It is.

<Aliphatic dicarboxylic acid unit>
Examples of the dicarboxylic acid constituting the dicarboxylic acid unit include an aliphatic dicarboxylic acid or a mixture of an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid. These dicarboxylic acids may be one type of aliphatic dicarboxylic acid, two or more types of aliphatic dicarboxylic acids, or a mixture of one or more types of aliphatic dicarboxylic acids and one or more types of aromatic dicarboxylic acids. Among these, those containing an aliphatic dicarboxylic acid as a main component are preferable. The main component referred to in the present invention is usually 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, particularly preferably 80 mol% or more, and most preferably 90 mol%, based on all dicarboxylic acid units. More than mol% is shown.

  Examples of the aromatic dicarboxylic acid include terephthalic acid and isophthalic acid, and examples of the aromatic dicarboxylic acid derivative include lower alkyl esters of aromatic dicarboxylic acid, specifically methyl ester, ethyl ester, propyl ester, and butyl. Examples include esters. Among these, terephthalic acid is preferable as the aromatic dicarboxylic acid, and dimethyl terephthalate is preferable as the derivative of the aromatic dicarboxylic acid.

  As the aliphatic dicarboxylic acid component, an aliphatic dicarboxylic acid or a derivative thereof is used. Specific examples of the aliphatic dicarboxylic acid include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, and cyclohexanedicarboxylic acid in a chain shape having 2 to 40 carbon atoms. Or alicyclic dicarboxylic acid is mentioned. Examples of the aliphatic dicarboxylic acid derivative include lower alkyl esters such as methyl ester, ethyl ester, propyl ester, and butyl ester of the aliphatic dicarboxylic acid, and cyclic acid anhydrides of the aliphatic dicarboxylic acid such as succinic anhydride. Can be used. Among these, as the aliphatic dicarboxylic acid, adipic acid, succinic acid, dimer acid or a mixture thereof is preferable from the viewpoint of physical properties of the obtained polymer, and those having succinic acid as a main component are particularly preferable. As the derivative of the aliphatic dicarboxylic acid, methyl esters of adipic acid and succinic acid, or a mixture thereof are more preferable. These dicarboxylic acids can be used alone or in combination of two or more.

In the present invention, these dicarboxylic acids may be derived from biomass resources. Biomass resources include, for example, wood, rice straw, rice husk, rice bran, old rice, corn, sugar cane, cassava, sago palm, okara, corn cob, tapioca cass, bagasse, vegetable oil scum, persimmon, buckwheat, soybean, fat, waste paper, papermaking residue , Marine product residue, livestock excrement, sewage sludge, food waste and the like. Among them, plant resources such as wood, rice straw, rice husk, rice bran, old rice, corn, sugar cane, cassava, sago palm, okara, corn cob, tapioca cass, bagasse, vegetable oil residue, buckwheat, soy, oil, waste paper, paper residue Wood, rice straw, rice husk, old rice, corn, sugar cane, cassava, sago palm, straw, oil and fat, waste paper, papermaking residue, most preferably corn, sugar cane, cassava, sago palm. These biomass resources generally contain a large amount of alkali metals and alkaline earth metals such as nitrogen element, Na, K, Mg, and Ca.

These biomass resources are not particularly limited, but are induced to carbon sources through known pretreatment and saccharification processes such as chemical treatment with acids and alkalis, biological treatment with microorganisms, physical treatment, and the like. Is done. The process usually includes, for example, a micronization process by pretreatment such as chipping, scraping, or crushing biomass resources, although it is not particularly limited. If necessary, a grinding process is further included with a grinder or a mill. The biomass resources refined in this way are further guided to a carbon source through pretreatment and saccharification processes, and specific methods include acid treatment and alkali treatment with strong acids such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid. , Chemical methods such as ammonia freezing steam explosion method, solvent extraction, supercritical fluid treatment, oxidant treatment, etc., physical methods such as fine grinding, steam explosion method, microwave treatment, electron beam irradiation, microorganisms and enzyme treatment Biological treatment such as hydrolysis may be mentioned.

  Carbon sources derived from the above biomass resources usually include hexoses such as glucose, mannose, galactose, fructose, sorbose, tagatose; pentoses such as arabinose, xylose, ribose, xylulose, ribulose; pentose, saccharose, starch, cellulose Disaccharides and polysaccharides such as butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, monoctinic acid, arachidic acid, eicosene Fats and oils such as acid, arachidonic acid, behenic acid, erucic acid, docosapentaenoic acid, docosahexaenoic acid, lignoceric acid, ceracolonic acid; fermentation of polyalcohols such as glycerin, mannitol, xylitol, ribitol Carbohydrate are used, these glucose, fructose, xylose are preferred, and glucose is particularly preferred. As a carbon source derived from a broader plant resource, cellulose which is a main component of paper is preferable.

Using these carbon sources, dicarboxylic acids can be produced by microbial conversion fermentation methods, chemical conversion methods including hydrolysis, dehydration reaction, hydration reaction, oxidation reaction, etc., and combinations of these fermentation methods and chemical conversion methods. Synthesized. Among these, the fermentation method by microbial conversion is preferable.
In general, the dicarboxylic acid used in the present invention is preferably less colored. The upper limit of the yellowness (YI value) of the dicarboxylic acid used in the present invention is usually 50 or less, preferably 20 or less, more preferably 10 or less, still more preferably 6 or less, and particularly preferably 4 or less. On the other hand, the lower limit thereof is not particularly limited, but is usually −20 or more, preferably −10 or more, more preferably −5 or more, particularly preferably −3 or more, and most preferably −1 or more. The use of a dicarboxylic acid exhibiting a low YI value is preferable because the produced polymer is less colored. On the other hand, a dicarboxylic acid exhibiting a high YI value is economically advantageous in that the capital investment required for its production is fixed and the production time may be short. In the present invention, the YI value is a value measured by a method based on JIS K7105.

<Aliphatic diol unit>
In the present invention, an aliphatic compound having two OH groups can be used as the aliphatic diol unit.
The aliphatic diol compound is not particularly limited as long as it has two OH groups, either a chain compound or a cyclic compound, but the lower limit of the number of carbons is 2 or more, and the upper limit is usually 10 or less. Preferably, an aliphatic diol of 6 or less is used. Among these, an even number of diols or a mixture thereof is preferable because a polymer having a higher melting point can be obtained.
Specific examples of the aliphatic diol include, for example, ethylene glycol, 1,3-propylene glycol, neopentyl glycol, 1,6-hexamethylene glycol, decamethylene glycol, 1,4-butanediol, and 1,4- And cyclohexanedimethanol. These may be used alone or as a mixture of two or more.

Among these, ethylene glycol, 1,4-butanediol, 1,3-propylene glycol and 1,4-cyclohexanedimethanol are preferable, and among them, ethylene glycol and 1,4-butanediol, and these In particular, a mixture mainly composed of 1,4-butanediol or 1,4-butanediol is particularly preferable. The main component here is usually 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, particularly preferably 80 mol% or more, and most preferably 90 mol%, based on all diol units. The above is shown.

Further, both terminal hydroxy polyethers may be used by mixing with the above aliphatic diol. As both-terminal hydroxy polyether, the carbon number is usually 4 or more, preferably 10 or more, and usually 1000 or less, preferably 200 or less, more preferably 100 or less.
Specific examples of both terminal hydroxy polyethers include diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly 1,3-propanediol, and poly 1,6-hexamethylene glycol. . In addition, a copolymerized polyether of polyethylene glycol and polypropylene glycol can be used. The use amount of these both terminal hydroxy polyethers is an amount calculated as a content in the polyester of usually 90% by weight or less, preferably 50% by weight or less, more preferably 30% by weight or less.

In the present invention, these diols may be derived from biomass resources. Specifically, the diol compound may be produced directly from a carbon source such as glucose by a fermentation method, or the dicarboxylic acid, dicarboxylic acid anhydride, or cyclic ether obtained by the fermentation method is converted into a diol compound by a chemical reaction. May be.
For example, 1,4-butanediol is produced by chemical synthesis from succinic acid, succinic anhydride, succinic acid ester, maleic acid, maleic anhydride, maleic acid ester, tetrahydrofuran, γ-butyrolactone, etc. obtained by fermentation. Alternatively, 1,4-butanediol may be produced from 1,3-butadiene obtained by a fermentation method. Among these, a method of hydrogenating succinic acid with a reduction catalyst to obtain 1,4-butanediol is efficient and preferable.

Furthermore, a method of producing a diol compound from biomass resources by a combination of known organic chemical catalytic reactions is also actively used. For example, when pentose is used as a biomass resource, a diol such as butanediol can be easily produced by a combination of a known dehydration reaction and catalytic reaction.
In the present invention, the upper limit of the content of an oxidation product of a diol such as 2- (4-hydroxybutyloxy) tetrahydrofuran used for producing a polymer having a good hue is usually 10,000 ppm, preferably 5000 ppm, more preferably in the diol. Is 3000 ppm, most preferably 2000 ppm. On the other hand, the lower limit is not particularly limited, but is usually 1 ppm, preferably 10 ppm, more preferably 100 ppm for reasons of economic efficiency of the purification process.
In the present invention, the diol is usually used as a polyester raw material after a purification step by distillation.

<Other copolymer components>
In the present invention, a copolymer component may be added in addition to the diol component and the dicarboxylic acid component.
Specific examples of the copolymer component include a bifunctional oxycarboxylic acid, an unsaturated dicarboxylic acid, a trifunctional or higher polyhydric alcohol and a trifunctional or higher polyvalent carboxylic acid (to form a crosslinked structure) Examples thereof include at least one polyfunctional compound selected from the group consisting of an anhydride and a tri- or higher functional oxycarboxylic acid. Among these copolymer components, oxycarboxylic acids are preferably used because polyesters having a high degree of polymerization tend to be easily produced.

Specific examples of the bifunctional oxycarboxylic acid include lactic acid, glycolic acid, hydroxybutyric acid, hydroxycaproic acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, and 2-hydroxyisocaprone. Examples of the acid include esters of oxycarboxylic acids, lactones, and derivatives of oxycarboxylic acid polymers.
These oxycarboxylic acids can be used alone or as a mixture of two or more. When optical isomers exist in these, any of D-form, L-form, and racemic form may be sufficient, and a form may be a solid, a liquid, or aqueous solution. Of these, readily available lactic acid or glycolic acid is particularly preferable. The form is preferably 30 to 95% by weight because an aqueous solution can be easily obtained. In this case, the use amount of the oxycarboxylic acid is usually 0.02 mol%, preferably 0.5 mol%, more preferably 1.0 mol%, and the upper limit is usually 0.02 mol% with respect to the raw material monomer. Usually, it is 30 mol%, preferably 20 mol%, more preferably 10 mol%.
Examples of the unsaturated dicarboxylic acid include itaconic acid, aconitic acid, fumaric acid, maleic acid and the like, and they can be used alone or as a mixture of two or more. Since the amount of unsaturated dicarboxylic acid used is a cause of gel generation, it is usually 5 mol% or less, preferably 0.5 mol% or less, more preferably based on all monomer units constituting the polyester. Is 0.05 mol% or less.

Specific examples of the trifunctional or higher polyhydric alcohol include glycerin, trimethylolpropane, pentaerythritol and the like, and they can be used alone or as a mixture of two or more.
Specific examples of the tri- or higher functional polycarboxylic acid or anhydride thereof include propanetricarboxylic acid, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, cyclopentatetracarboxylic anhydride, and the like. It can also be used as a mixture of two or more.

Specific examples of the tri- or higher functional oxycarboxylic acid include malic acid, hydroxyglutaric acid, hydroxymethylglutaric acid, tartaric acid, citric acid, hydroxyisophthalic acid, hydroxyterephthalic acid, and the like. It can also be used as a mixture of In particular, malic acid, tartaric acid, and citric acid are preferable because of easy availability.
Since the amount of the above trifunctional or higher compound is a cause of gel generation, it is usually 5 mol% or less, preferably 0.5 mol% or less, based on all monomer units constituting the polyester. More preferably, it is 0.2 mol% or less.

<Chain extender>
In the method of the present invention, a chain extender such as a carbonate compound or a diisocyanate compound can be used for the polyester of the present invention, but the amount thereof is usually carbonate based on the total monomer units constituting the polyester. Bonds and urethane bonds are 10 mol% or less. However, from the viewpoint of using the polyester of the present invention as a biodegradable resin, diisocyanate has a problem in that a highly toxic diamine is generated in the decomposition process and accumulates in the soil, and diphenyl is generally used as a carbonate compound. The carbonate system also has a problem that highly toxic by-product phenol and unreacted diphenyl carbonate remain in the polyester, so the amount used is preferably a carbonate bond with respect to all monomer units constituting the polyester. Less than 1 mol%, more preferably 0.5 mol% or less, particularly preferably 0.1 mol%, and urethane bonds are preferably less than 0.06 mol%, more preferably 0.01 mol% or less. Especially preferably, it is 0.001 mol% or less.

  Specific examples of the carbonate compound include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, ethylene carbonate, diamyl carbonate, and dicyclohexyl. Examples include carbonate. In addition, carbonate compounds composed of the same or different hydroxy compounds derived from hydroxy compounds such as phenols and alcohols can be used.

Specifically, as the diisocyanate compound, 2,4-tolylene diisocyanate,
Known mixtures of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, etc. Examples of the diisocyanate are as follows.
Moreover, you may use a dioxazoline, a silicate ester, etc. as another chain extender. Specific examples of the silicate ester include tetramethoxysilane, dimethoxydiphenylsilane, dimethoxydimethylsilane, and diphenyldihydroxylane. Furthermore, a small amount of peroxide may be added to increase the melt tension.

<Production method of polyester>
As a method for producing the polyester in the present invention, a conventionally known method can be used. For example, after performing the esterification reaction and / or transesterification reaction between the aliphatic dicarboxylic acid component and the diol component, the pressure is reduced. It can also be produced by a general method of melt polymerization, such as a polycondensation reaction, or a known solution heating dehydration condensation method using an organic solvent. A method of producing a polyester by melt polymerization performed in a solvent is preferred.

The timing of bringing the catalyst into contact with the reaction raw material is not particularly limited as long as it is before the polycondensation reaction, and it may be added at the time of charging the raw material, but the catalyst coexists in a situation where a lot of water is present or generated. Then, the catalyst is deactivated and foreign matter may be precipitated, which may impair the quality of the product. Therefore, it is preferable to add after the esterification reaction and / or transesterification reaction.
The lower limit of the amount of titanium atoms in the catalyst relative to the polyester to be produced is usually 1 ppm, preferably 10 ppm, more preferably 15 ppm, particularly preferably 20 ppm, and the upper limit is usually 30000 ppm, preferably 150 ppm, more preferably 100 ppm, Particularly preferred is 70 ppm. When the amount of titanium is not more than the above upper limit, it is economically advantageous and the thermal stability of the polymer becomes good. Moreover, it is preferable at the point of polymerization activity as it is more than the said minimum, and decomposition | disassembly of the polymer during polymer manufacture does not occur easily. Further, the smaller the amount of titanium, the smaller the amount of catalyst is preferred in that the carboxyl group terminal concentration of the produced polyester is reduced.
The lower limit of the amount of magnesium atoms in the catalyst with respect to the produced polyester is usually 1 ppm, preferably 5 ppm, more preferably 10 ppm, particularly preferably 20 ppm, and the upper limit is usually 200 ppm, preferably 100 ppm, more preferably 70 ppm, Particularly preferred is 50 ppm. If the amount of magnesium is not more than the above upper limit, it is economically advantageous and the color tone of the polymer tends to be good. On the other hand, if it is at least the above lower limit, it is preferable from the viewpoint of polymerization activity, and the polymer is hardly decomposed during the production of the polymer.
The lower limit of the amount of phosphorus atoms in the catalyst with respect to the produced polyester is usually 1 ppm, preferably 10 ppm, more preferably 20 ppm, particularly preferably 30 ppm, and the upper limit is usually 200 ppm, preferably 100 ppm, more preferably 70 ppm, Particularly preferred is 50 ppm. When the amount of phosphorus is not more than the above upper limit, it is economically advantageous and the polymerization activity is high, so that the polymer is hardly decomposed during the production of the polymer. Moreover, it is preferable at the point of the color tone of a polymer that the amount of phosphorus is more than the said minimum.
Conventionally known ranges can be adopted as conditions such as reaction temperature, time, and pressure.

The lower limit of the reaction temperature of the esterification reaction and / or transesterification reaction of the dicarboxylic acid component and the diol component is usually 150 ° C., preferably 180 ° C. or higher, more preferably 200 ° C., and the upper limit is usually 260 ° C. or lower, preferably Is 250 ° C. or lower, more preferably 235 ° C. The reaction atmosphere is usually an inert gas atmosphere such as nitrogen or argon. The lower limit of the reaction pressure is usually 10 kPa, preferably 30 kPa, more preferably 50 kPa, and the upper limit is 133 kPa, preferably 120 kPa, particularly preferably 110 kPa. Among these, normal pressure (101.3 kPa) is preferable.
The reaction time is usually 1 hour or longer, and the upper limit is usually 10 hours, preferably 4 hours.

In the subsequent polycondensation reaction, the pressure is set at a lower limit of usually 0.01 × 10 ³ Pa, preferably 0.0.
3 × 10 ³ Pa, more preferably 0.06 × 10 ³ Pa, and the upper limit is usually 1.4 × 10 ³ Pa.
It is performed under a vacuum degree of Pa, preferably 1.0 × 10 ³ Pa, more preferably 0.4 × 10 ³ Pa. When the pressure during the production of the polymerization is not more than the above upper limit, the polymerization rate of the polyester is high, and accordingly, a decrease in molecular weight or coloration due to thermal decomposition of the polyester hardly occurs, and it is easy to obtain a polyester having practically sufficient characteristics. On the other hand, if it is above the above lower limit, an expensive equipment investment such as an ultra-high vacuum apparatus is not required, and molecular weight reduction and coloration due to thermal decomposition of polyester due to longer polymerization production time of polyester are less likely to occur.

  The lower limit of the reaction temperature is usually 150 ° C., preferably 180 ° C., more preferably 200 ° C., particularly preferably 220 ° C., and the upper limit is usually 280 ° C., preferably 270 ° C., more preferably 265 ° C., particularly preferably 260 It is in the range of ° C. If the temperature is equal to or higher than the above lower limit, the polymerization reaction rate is high, a polyester having a high degree of polymerization can be produced in a short time, and a high power agitator is not essential, which is economically advantageous. On the other hand, when the reaction temperature is not more than the above upper limit, it is preferable from the viewpoint of polymerization rate, and it is difficult to cause thermal decomposition of the polymer at the time of production, and it becomes easy to produce polyester having a high degree of polymerization. In the present invention, control of the reaction temperature is important.

  The lower limit of the reaction time is usually 2 hours, and the upper limit is usually 15 hours, preferably 8 hours, more preferably 6 hours. If the reaction time is not less than the above lower limit, the reaction proceeds sufficiently, a polyester having a high degree of polymerization is obtained, the tensile elongation at break is high, and the terminal amount of the carboxyl group tends to decrease, and the tensile elongation at break is deteriorated. Is less likely to occur. On the other hand, if the reaction time is less than the above upper limit, the molecular weight is less likely to decrease due to the thermal decomposition of the polyester, the tensile elongation at break is less likely to decrease, and increases due to the thermal decomposition of the carboxyl group end amount that affects the durability of the polymer. Is unlikely to occur.

In the present invention, as a method for producing a polyester, after performing an esterification reaction and / or transesterification reaction of a conventional dicarboxylic acid component containing an aliphatic dicarboxylic acid and an aliphatic diol component, under reduced pressure, A method of increasing the degree of polymerization of the polyester while distilling off the diol produced by the ester exchange reaction at the alcohol terminal of the polyester, or distilling off the aliphatic dicarboxylic acid and / or its acid anhydride from the aliphatic carboxylic acid terminal of the polyester. However, a method for increasing the degree of polymerization of the polyester is used.
In the present invention, even if the raw material charge ratio is high, the polymerization rate is high, and a polyester having a high polymerization degree and excellent color tone can be easily obtained without using a chain extender, etc. It is preferable to use a method of increasing the degree of polymerization of the polyester while distilling off the diol produced by the transesterification reaction at the alcohol end. In this case, the diol component is usually removed by heating and distilling the diol component during the polycondensation reaction under reduced pressure in the latter stage of the melt polymerization step. Since it is easy to become a cyclic ether, it may be distilled by heating in the form of a cyclic ether. Moreover, in that case, you may remove with aliphatic carboxylic acid and / or its acid anhydride. Furthermore, the method of distilling off both the diol component or cyclic ether and the acid anhydride of the dicarboxylic acid component is preferable from the viewpoint of improving the polymerization rate.
Here, when a polyester is produced using a method for increasing the degree of polymerization of the polyester while distilling off the diol produced by the transesterification reaction at the alcohol end of the polyester, the diol and / or cyclic ether and fat to be distilled off are used. The amount of diol and / or cyclic ether in the total amount of the aliphatic dicarboxylic acid and / or anhydride thereof is usually 30 mol% or more, preferably 50 mol, from the viewpoint of easy production of a polyester having a high degree of polymerization. % Or more, more preferably 70 mol% or more, particularly preferably 80 mol% or more, and most preferably 90 mol% or more.

  In the present invention, the latter aliphatic dicarboxylic acid and / or acid anhydride thereof is distilled off because the polymerization rate is high even at a lower temperature and a polyester having a high degree of polymerization can be easily obtained without using a chain extender. You may use the method to do. In this case, the removal of the aliphatic carboxylic acid and / or its anhydride is usually carried out by distilling the aliphatic dicarboxylic acid and / or its acid anhydride during the polycondensation reaction under reduced pressure in the latter stage of the melt polymerization step. However, the aliphatic dicarboxylic acid easily becomes an acid anhydride under the polycondensation reaction condition, and is often distilled by heating in the form of an acid anhydride. At this time, the chain or cyclic ether derived from the diol and / or the diol may also be removed together with the aliphatic dicarboxylic acid and / or the acid anhydride thereof. Furthermore, the method of distilling off both the dicarboxylic acid component and the diol component of the cyclic monomer is preferable because the polymerization rate is improved.

  Here, when manufacturing polyester using the method of distilling aliphatic dicarboxylic acid and / or its acid anhydride, the total amount of aliphatic dicarboxylic acid and / or its anhydride and diol distilled off. The amount of the aliphatic dicarboxylic acid and / or anhydride thereof is usually 30 mol% or more, preferably 50 mol% or more, more preferably 70 mol% or more, particularly preferably 80 mol% or more, and most preferably 90 mol%. When it is at least mol%, a polyester having a high degree of polymerization can be easily produced.

  In the present invention, when a polyester having a high degree of polymerization is produced by a method of distilling off an aliphatic dicarboxylic acid and / or its acid anhydride, the reaction vessel side exhaust of the exhaust pipe for decompression connecting the vacuum pump and the reactor is used. If the temperature of the mouth is maintained at a temperature equal to or lower than the melting point of the aliphatic dicarboxylic acid anhydride or the boiling point of the aliphatic dicarboxylic acid anhydride at the degree of vacuum during the polycondensation reaction, the acid anhydride produced is reduced. This is preferable because it can be efficiently removed from the reaction system and the desired high degree of polymerization polyester can be produced in a short time. Furthermore, it is more preferable to maintain the piping temperature from the reaction vessel side exhaust port to the condenser at the lower of the melting point of the acid anhydride or the boiling point in the degree of vacuum during the polycondensation reaction.

  In the present invention, the molar ratio of the diol component and the dicarboxylic acid component for obtaining a polyester excellent in the desired degree of polymerization and color tone varies depending on the type of raw material, but the amount of the diol component relative to 1 mol of the dicarboxylic acid component is The lower limit 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, it is 2.5 mol, particularly preferably 2.0 mol, and most preferably 1.5 mol. It is preferable from a polymerization activity as it is more than the said minimum. Further, if it is not more than the above upper limit, the color tone of the resulting polyester resin is hardly deteriorated, and the amount of the diol component used as a raw material may be small, which is economically advantageous. As described above, according to the present invention, it is possible to obtain a polyester having a high polymerization rate and excellent color tone without being severely restricted by the raw material charge molar ratio in the batch reaction. That is, it is possible to increase the polymerization productivity by appropriately selecting the range of the raw material charge molar ratio. Also, in continuous reaction, it is possible to obtain a polyester having a high polymerization rate and excellent color tone without being severely restricted by the raw material charge molar ratio, and the reaction conditions can be selected from a wide range. It can be said that this is an industrially advantageous process because it does not require complicated control of the raw material component ratio when introducing the raw material.

In the present invention, in the case of using a mixture of an aromatic dicarboxylic acid or an alkyl ester thereof in addition to the aliphatic carboxylic acid as the dicarboxylic acid component, the order of use is not particularly limited,
For example, as a first, raw material monomers can be put into a reaction vessel in a batch and reacted, and as a second, after a diol component and an aliphatic dicarboxylic acid or a derivative thereof are esterified or transesterified. Various methods such as a method in which a diol component and an aromatic dicarboxylic acid or a derivative thereof are subjected to an esterification reaction or a transesterification reaction and further a polycondensation reaction can be employed.

The polyester production method of the present invention includes a batch reaction and a continuous reaction. A batch reaction is a reaction in which an esterification reaction and / or a transesterification reaction and a polycondensation reaction are performed in a batch manner, and a continuous reaction is a continuous reaction between an esterification reaction and / or a transesterification reaction and a polycondensation reaction. It is a method to do.
In the present invention, a known vertical or horizontal stirred tank reactor can be used as a reaction apparatus for producing polyester batchwise. For example, melt polymerization is performed in two stages of esterification and / or transesterification and reduced pressure polycondensation using the same or different reactors, and a vacuum pump and a reactor are used as the reduced pressure polycondensation reactor. A method of using a stirred tank reactor equipped with a evacuation pipe for decompression to be connected can be mentioned. 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 volatile components and unreacted monomers generated during the condensation polymerization reaction are recovered by the condenser. Used.

  In the present invention, the reaction apparatus for continuously producing polyester is not particularly limited as the type of the esterification reaction tank. For example, a known vertical stirring complete mixing layer, vertical heat convection mixing layer, tower A type continuous reaction tank or the like can be used. Similarly, the type of the polycondensation reaction tank is not particularly limited, and for example, a known vertical stirring polymerization tank, horizontal stirring polymerization tank, thin film evaporation polymerization tank, or the like can be used. The esterification reaction tank and the polycondensation reaction tank may be one or a plurality of tanks in which different types of tanks are connected in series, but a horizontal reactor excellent in surface renewability is preferable. .

Hereinafter, preferred embodiments of a method for producing an aliphatic polyester resin will be described with reference to the accompanying drawings. FIG. 1 is an explanatory diagram of an example of an esterification reaction step that can be employed as the production method of the present invention, and FIG. 2 is an explanatory diagram of an example of a polycondensation step that can be employed as the production method of the present invention.
In FIG. 1, succinic acid as a raw material is usually mixed with 1,4-butanediol in a raw material mixing tank (not shown), and is fed from the raw material supply line (1) to the reactor (A) in the form of slurry or liquid. Supplied. When the catalyst is added during the esterification reaction, the catalyst of the present invention is supplied from the esterification tank catalyst supply line (3) after making a 1,4-butanediol solution in a catalyst preparation tank (not shown). The In FIG. 1, the esterification tank catalyst supply line (3) is connected to the 1,4-butanediol recirculation line (2), and both are mixed and then supplied to the liquid phase part of the reactor (A). showed that.

The gas distilled from the reactor (A) is separated into a high-boiling component and a low-boiling component in the rectification column (C) through the distillation line (5). Usually, the main component of the high boiling component is 1,4-butanediol, and the main components of the low boiling component are water and tetrahydrofuran.
The high-boiling components separated in the rectification column (C) are extracted from the extraction line (6), and are partially circulated from the recirculation line (2) to the reactor (A) via the pump (D). And a part is returned from the circulation line (7) to the rectification column (C). Further, the surplus is extracted outside from the extraction line (8). On the other hand, the light boiling component separated in the rectification column (C) is extracted from the gas extraction line (9), condensed in the condenser (G), passed through the condensate line (10), and then into the tank (F). Is temporarily stored. A part of the light boiling components collected in the tank (F) is returned to the rectification column (C) through the extraction line (11), the pump (E) and the circulation line (12), and the remainder is extracted. It is extracted outside through the line (13). The condenser (G) is connected to an exhaust device (not shown) via a vent line (14). The oligomer produced in the reactor (A) is withdrawn via a withdrawal pump (B) and an oligomer withdrawal line (4).

In addition, in the process shown in FIG. 1, although the esterification tank catalyst supply line (3) is connected with the recirculation line (2), both may be independent. Moreover, the raw material supply line (1) may be connected to the liquid phase part of the reactor (A).
When adding a catalyst to the oligomer before polycondensation, after adjusting to a predetermined catalyst concentration in a preparation tank (not shown), supply of 1,4-butanediol through the catalyst supply line (L7) in FIG. After further diluting with 1,4-butanediol via the line (L8), it is supplied to the oligomer extraction line (4) shown in FIG.

Next, the oligomer supplied to the first polycondensation reactor (a) is polycondensed under reduced pressure into a prepolymer, and then passes through the extraction gear pump (c) and the extraction line (L1). The second polycondensation is fed to the reactor (d). In the second polycondensation reactor (d), polycondensation usually proceeds at a lower pressure than that of the first polycondensation reactor (a) to become a polymer. The obtained polymer is supplied to the third polycondensation tank (k) through the extraction gear pump (e) and the extraction line (L3). The third polycondensation reactor (k) is a horizontal reactor comprising a plurality of stirring blade blocks and equipped with a biaxial self-cleaning type stirring blade. The polymer introduced from the second polycondensation reactor (d) to the third polycondensation reactor (k) through the extraction line (L3) is further subjected to polycondensation here, and then the extraction gear pump (m ) And the extraction line (L5), and is extracted from the die head (g) in the form of a melted strand, cooled with water, etc., and then cut into a pellet by the rotary cutter (h). Reference numerals (L2), (L4), and (L6) denote vent lines of the first polycondensation reactor (a), the second polycondensation reactor (d), and the third polycondensation reactor (k), respectively. It is.

<Polyester and its use>
The preferred polyester obtained by the production method of the present invention is such that the content of titanium atom contained in the polyester is 1 ppm, more preferably 5 ppm, particularly preferably 10 ppm as the amount converted to metal atoms, The upper limit is preferably 30000 ppm, more preferably 3000 ppm, particularly preferably 500 ppm, and most preferably 250 ppm.

  The polyester produced by the method of the present invention usually has a feature that the amount of carboxylic acid terminal that adversely affects the thermal stability of the polymer is small, so that it has excellent thermal stability and little deterioration in quality during molding, It has the characteristic that there are few side reactions, such as the cutting | disconnection of a terminal group and the cutting | disconnection of a principal chain at the time of melt molding. The number of terminal COOH groups of the polyester obtained by the present invention is usually 60 eq / ton or less, although it depends on the degree of polymerization of the polyester. Therefore, the number of terminal COOH groups of the preferred polyester produced in the present invention is usually 60 eq / ton or less, preferably 40 eq / ton or less, more preferably 30 eq / ton or less. On the other hand, when the carboxyl group terminal amount becomes extremely small, the polymerization rate becomes slow, and it becomes difficult to produce a polymer having a high degree of polymerization. For such reasons, the lower limit of the number of terminal COOH groups of the polyester is usually 0.1 eq / ton or more, more preferably 1 eq / ton.

  The reduced viscosity (ηsp / C) value of the polyester produced in the present invention is usually preferably 1.6 or more, more preferably 2.0 or more, more preferably, because practically sufficient mechanical properties can be obtained. 2.2 or more is particularly preferable, and 2.3 or more is most preferable. The reduced viscosity (ηsp / C) value is usually 6.0 or less, preferably 5.0 or less, more preferably from the viewpoint of operability such as ease of extraction after polyester polymerization and ease of molding. 4.0 or less.

The reduced viscosity as referred to in the present invention is measured under the following measurement conditions.
[Reduced viscosity (ηsp / C) measurement conditions]
Viscosity tube: Ubbelohde viscosity tube Measurement temperature: 30 ° C
Solvent: Phenol / tetrachloroethane (1: 1 weight ratio) solution Polyester concentration: 0.5 g / deciliter In the middle of the production method of the present invention or the resulting polyester, various additives such as heat Stabilizers, antioxidants, crystal nucleating agents, flame retardants, antistatic agents, mold release agents, ultraviolet absorbers, and the like may be used during polymerization.

In addition to the various additives shown above at the time of molding, glass fiber, carbon fiber, titanium whisker, mica, talc, CaCO ₃ , TiO ₂ , silica and other reinforcing agents and fillers should be added for molding. You can also.
The polyester obtained by the production method of the present invention is excellent in heat resistance and color tone, in addition, excellent in hydrolysis resistance and biodegradability, and can be produced at low cost, so it is suitable for various film applications and injection molded product applications. ing.

Specific applications include injection molded products (for example, fresh food trays, fast food containers, outdoor leisure products, etc.), extruded products (films, sheet fishing lines, fishing nets, vegetation nets, water retaining sheets, etc.), hollow molding Products (bottles, etc.), agricultural films, coating materials, fertilizer coating materials, laminate films, plates, stretched sheets, monofilaments, multifilaments, non-woven fabrics, flat yarns, staples, crimped fibers, with streaks 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 material, cold box, It can be used for cushion material films, synthetic paper, paper laminate, and the like.

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.
<Analysis of metal elements in catalyst>
A plasma emission spectroscopic analyzer (ICP-AES ULTRACE JY-138U type manufactured by JOBIN YVON) was used for 0.1 g of a sample obtained by wet decomposition with hydrogen peroxide in the presence of sulfuric acid in a Kjeldahl flask and then with a constant volume of distilled water. ), And converted to the metal content (% by weight) in the catalyst.
<PH analysis of catalyst solution>
Using an automatic titrator (AUT-301 type) manufactured by Toa DKK, the pH electrode was immersed in a liquid catalyst and measured under the atmosphere.

<Measurement of reduced viscosity (ηsp / c)>
Hold 0.25 g of pellet-shaped polyester resin at 110 ° C. for 30 minutes with a mixture of phenol / tetrachloroethane (weight ratio 1/1) as a solvent and a concentration (c) of 0.5 g / dl (deciliter). Then, using a Ubbelohde capillary viscosity tube, the relative viscosity (ηrel) with the stock solution was measured at 30 ° C., and the specific viscosity (ηsp) and concentration (ηsp) and concentration determined from this relative viscosity (ηrel) -1 ( The ratio (ηsp / c) to c) was determined.

<Terminal carboxyl group content analysis>
After pulverizing the pelletized polyester resin, it was dried at 140 ° C. for 15 minutes in a hot air dryer, and 0.1 g was accurately weighed from a sample cooled to room temperature in a desiccator, and taken into a test tube, and 3 cm ^{3 of} benzyl alcohol Was added and dissolved in 195 ° C. for 3 minutes while blowing dry nitrogen gas, and then 5 cm ³ 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 (liter) ^-1 benzyl alcohol solution of sodium hydroxide while blowing dry nitrogen gas, and change from yellow to red. It was finished at the time. Further, as a blank, the same operation was carried out without dissolving the polyester resin sample, and the terminal carboxyl group amount (acid value) was calculated by the following formula <1>.

Terminal carboxyl amount (equivalent / ton) = (ab) × 0.1 × f / w <1>
(Here, a is the amount of 0.1 mol·l (liter) required for titration ⁻¹ benzyl alcohol solution of sodium hydroxide (microliter), b is 0.1 mol·l required for titration with a blank. l (liter) ⁻¹ amount of sodium hydroxide in benzyl alcohol solution (microliter), w is the amount of polyester resin sample (g), f is 0.1 mol·l (liter) ⁻¹ sodium hydroxide (The titer of benzyl alcohol solution.)
The titer (f) of benzyl alcohol solution of 0.1 mol·l (liter) ⁻¹ sodium hydroxide was determined by the following method. Collect 5 cm ³ of methanol in a test tube and add 1-2 drops as an indicator of phenol red in ethanol solution. titrated to color change point in I mol · l ^(liters) of sodium hydroxide ^-1 benzyl alcohol solution 0.4 cm ^3, then 0 hydrochloric acid aqueous solution of known titer of 0.1 mol · l ^{(l) -1} as a standard solution .2 cm ^{3 was} sampled and added, and again titrated with 0.1 mol·l (liter) ⁻¹ sodium hydroxide in benzyl alcohol to the discoloration point (the above operations were carried out under dry nitrogen gas blowing). . The titer (f) was calculated by the following formula <2>.

Sodium hydroxide titer (f) = 0.1mol · l ^(liter) titer × amount of collected aqueous hydrochloric acid 0.1N aqueous hydrochloric acid ^{-1 (μl) /0.1mol} · l ^{(l) -1} Titration of benzyl alcohol solution (microliter) <2>

<Color tone measurement>
A pellet-shaped polyester resin is filled in a cylindrical powder measurement cell having an inner diameter of 30 mm and a depth of 12 mm, and a colorimetric color difference meter Z300A (Nippon Denshoku Industries Co., Ltd.) is used to obtain Reference Example 1 of JIS Z8730. The color b value based on the color coordinates of Hunter's color difference formula in the Lab display system to be described was determined as a simple average value of values measured at four locations by rotating the measurement cell by 90 degrees by the reflection method.

[Example 1]
[Preparation of catalyst for polycondensation]
62.0 g of magnesium acetate tetrahydrate was placed in a 500 cm ³ glass eggplant-shaped flask equipped with a stirrer, and 250 g of absolute ethanol (purity 99% by weight or more) was further added. Further, 35.8 g 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, 75.0 g 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 a 1000 cm ³ eggplant-shaped flask and concentrated in an oil bath at 60 ° C. under reduced pressure using an evaporator. After 1 hour, most of the ethanol was distilled off, leaving a translucent viscous liquid. The temperature of the oil bath was further increased to 80 ° C., and further concentration was performed under a reduced pressure of 5 Torr. The viscous liquid gradually changed from the surface to a powder form, and was completely powdered after 2 hours. Then, it returned to normal pressure using nitrogen, and it cooled to room temperature, and obtained 108 g of pale yellow powder. The metal element analysis value of the obtained catalyst was as follows: titanium atom content was 10.3 wt%, magnesium atom content was 6.8 wt%, and phosphorus atom content was 7.8 wt%. T / P = 0.77 and M / P = 1.0. In addition, the weight was reduced by 37% by weight with respect to the total weight of the raw material excluding the ethanol solvent. (Note that even if the catalyst used in the method of the present invention is analyzed by nuclear magnetic resonance spectroscopy, ethanol derived from ethyl acid phosphate, butanol derived from tetra-n-butyl titanate and alkoxide groups derived from 1,4-butanediol From this, it was found that the organic alkoxide group was not bonded to titanium in the catalyst used in the method of the present invention. -It melt | dissolved in butanediol and it prepared so that it might become 34,000 ppm as a titanium atom. The storage stability in 1,4-butanediol was good, and the catalyst solution stored at 40 ° C. under a nitrogen atmosphere did not show the formation of precipitates for at least 40 days. The catalyst solution had a pH of 6.1.

[Production of aliphatic polyester resin]
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer, and a vacuum outlet, 100.3 g (0.85 mol) succinic acid and 81.9 g (0.91 mol) 1,4-butanediol were used as raw materials. ), 0.37 g of malic acid (2.8 × 10 ⁻³ mol, 0.33 mol% based on succinic acid) was charged, and the inside of the system was put into a nitrogen atmosphere by nitrogen-vacuum substitution.

Next, the temperature in the system was raised to 230 ° C. over 1 hour while stirring, and the reaction was carried out at this temperature for 1 hour. Thereafter, the catalyst solution was added. The amount added was 50 ppm as titanium atoms per polyester resin obtained. The temperature was raised to 250 ° C. over 30 minutes, and at the same time, the pressure was reduced to 0.07 × 10 ³ Pa over 1 hour 30 minutes, and the reaction was further continued for 4.9 hours under a reduced pressure of 0.07 × 10 ³ Pa. A polyester resin was obtained. 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 the polymerization were water, succinic anhydride, tetrahydrofuran, a cyclic monomer of succinic acid and butanediol, and a small amount of 1,4-butanediol. The polyester obtained had a reduced viscosity of 2.38, and the terminal polyester group content of the obtained polyester was 23 equivalents / ton, and the color tone b was 1.7.
Subsequently, the obtained polymer was pressed and melted at 150 ° C. for 3 minutes using a table press, and further pressed at 150 ° C. and 20 MPa for 2 minutes to obtain a film having a thickness of 150 μm. Using a test piece punched out of the obtained press film into a dumbbell shape (length: 10 cm), tensile elongation at break was measured at a tensile speed of 200 mm / min, a distance between marked lines = 10 mm, and a distance between chucks = 60 mm. As a result, the tensile elongation was 400%. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Comparative Example 1]
[Preparation of catalyst for polycondensation]
In a 300 cm ^-3 glass Erlenmeyer flask containing a stir bar, 96 g of 1,4-butanediol and 4 g of organic titanium-based tetra-n-butyl titanate were added, and the temperature was raised while stirring with a magnetic stirrer. After complete dissolution, stirring was stopped and the solution was stored at 40 ° C. The storage stability in 1,4-butanediol was poor and clouded after 4 hours.
[Production of aliphatic polyester resin]
Except having changed the catalyst, the polymer was obtained like the manufacturing method of the polyester resin of Example 1. The polyester obtained had a reduced viscosity of 1.72, a terminal carboxyl group of 17 equivalents / ton, and a color tone L, a and b values of 77.7, -0.9 and 5.5, respectively. .
Subsequently, the obtained polymer was pressed and melted at 150 ° C. for 3 minutes using a table press, and further pressed at 150 ° C. and 20 MPa for 2 minutes to obtain a film having a thickness of 150 μm. Using a test piece punched out of the obtained press film into a dumbbell shape (length: 10 cm), tensile elongation at break was measured at a tensile speed of 200 mm / min, a distance between marked lines = 10 mm, and a distance between chucks = 60 mm. As a result, the tensile elongation was 280%. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

  Thus, in the production process of polyester using a catalyst in which deteriorated or aggregated catalyst has been deposited by storage, the production time may vary from production to production, or clogging of piping during transfer due to catalyst deposits, etc. It becomes a process with poor manufacturing stability. In addition, the appearance of the product is deteriorated due to the inclusion of precipitates in the product, and the quality of the product is impaired, for example, the mechanical properties at the time of film forming are deteriorated.

[Example 2]
[Preparation of catalyst for polycondensation]
100 parts by weight of magnesium acetate tetrahydrate was placed in a glass eggplant-shaped flask equipped with a stirrer, and 400 parts by weight of absolute ethanol (purity 99% by weight or more) was further added. Further, 65.3 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, 122.2 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 the ethanol was distilled off, leaving a translucent viscous liquid. The temperature of the oil bath was further increased to 80 ° C., and further concentration was performed under a reduced pressure of 5 Torr. The viscous liquid gradually changed from the surface to a powder form, and was completely powdered after 2 hours. Then, it returned to normal pressure using nitrogen, and it cooled to room temperature, and obtained 175 weight part of pale yellow powder. The metal element analysis value of the obtained catalyst was as follows: titanium atom content was 10.3 wt%, magnesium atom content was 6.8 wt%, and phosphorus atom content was 7.8 wt%. T / P = 0.78 and M / P = 1.0. In addition, a 39% weight reduction was observed due to production relative to the total weight of the raw material excluding the ethanol solvent. (Note that even if the catalyst used in the method of the present invention is analyzed by nuclear magnetic resonance spectroscopy, ethanol derived from ethyl acid phosphate, butanol derived from tetra-n-butyl titanate and alkoxide groups derived from 1,4-butanediol From this, it was found that organic alkoxide groups were not bonded to titanium in the catalyst used in the method of the present invention. It was dissolved in butanediol and prepared so as to have a titanium atom of 10,000 ppm, and the storage stability in 1,4-butanediol was good, and the catalyst solution stored at 40 ° C. in a nitrogen atmosphere precipitated for at least 40 days. The catalyst solution had a pH of 6.1.

[Production of aliphatic polyester resin]
100 parts by weight of succinic acid containing 0.14% by weight of malic acid in succinic acid as a raw material in a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a vacuum outlet 99.2 parts by weight of butanediol and 0.24 parts by weight of malic acid (total malic acid amount 0.33 mol% with respect to succinic acid) were charged, and the system was placed in a nitrogen atmosphere by nitrogen-vacuum substitution.
Next, the temperature in the system was raised to 230 ° C. over 1 hour while stirring, and the reaction was carried out at this temperature for 1 hour. Thereafter, the catalyst solution was added. The amount added was 50 ppm as titanium atoms per polyester resin obtained. The temperature was raised to 250 ° C. over 30 minutes, and at the same time, the pressure was reduced to 0.06 × 10 ³ Pa over 1 hour 30 minutes, and the reaction was further continued for 4.2 hours under a reduced pressure of 0.06 × 10 ³ Pa. A polyester resin was obtained. 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 the polymerization were water, succinic anhydride, tetrahydrofuran, a cyclic monomer of succinic acid and butanediol, and a small amount of 1,4-butanediol. The polyester obtained had a reduced viscosity of 2.21, the terminal polyester group content of the obtained polyester was 23 equivalents / ton, and the color tone b value was 1.9.
Subsequently, the obtained polymer was pressed and melted at 150 ° C. for 3 minutes using a table press, and further pressed at 150 ° C. and 20 MPa for 2 minutes to obtain a film having a thickness of 150 μm. Using a test piece punched into a dumbbell shape (length: 10 cm) from the obtained press film, the tensile breaking elongation was measured at a tensile speed of 200 mm / min, a distance between marked lines = 10 mm, and a distance between chucks = 60 mm. As a result, the tensile elongation was 390%. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Example 3]
A polymer was obtained in the same manner as in Example 2 except that 114.5 parts by weight of 1,4-butanediol as a raw material was used when producing the aliphatic polyester resin. Table 1 shows the polymerization time and the physical properties of the obtained polymer.
[Example 4]
When producing an aliphatic polyester resin, 13 of 1,4-butanediol as a raw material was used.
A polymer was obtained in the same manner as in Example 2 except that 7.4 parts by weight were used. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Example 5]
A polymer was obtained in the same manner as in Example 2 except that when the aliphatic polyester resin was produced, the amount of catalyst added was 40 ppm as a titanium atom per polyester resin obtained. Table 1 shows the polymerization time and the physical properties of the obtained polymer.
[Example 6]
A polymer was obtained in the same manner as in Example 2 except that when the aliphatic polyester resin was produced, the temperature was raised to 240 ° C. over 30 minutes after the addition of the catalyst. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Comparative Example 2]
A polymer was obtained in the same manner as in the polyester resin production method of Example 1, except that the catalyst produced in Comparative Example 1 was used and 102.1 g of 1,4-butanediol as a raw material was used. Table 1 shows the polymerization time and the physical properties of the obtained polymer.
[Comparative Example 3]
A polymer was obtained in the same manner as in the polyester resin production method of Example 1, except that the catalyst prepared in Comparative Example 1 was used and 141.3 g of 1,4-butanediol as a raw material was used. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Example 7]
Except for adding malic acid as a raw material when producing an aliphatic polyester resin, only the malic acid content in succinic acid (0.16% by weight) was used. A polymer was obtained. Table 1 shows the polymerization time and the physical properties of the obtained polymer.
[Example 8]
A polymer was obtained in the same manner as in Example 2 except that malic acid as a raw material was not added and succinic acid not containing malic acid was used in the succinic acid when the aliphatic polyester resin was produced. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Comparative Example 4]
When the aliphatic polyester resin was produced using the catalyst of Comparative Example 1, only the malic acid content in succinic acid (0.16% by weight) was added without adding malic acid as a raw material. A polymer was obtained in the same manner as in [Production of aliphatic polyester resin] in Example 1. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Example 9]
[Preparation of catalyst for polycondensation]
100 parts by weight of magnesium acetate tetrahydrate, 1500 parts by weight of ethanol, and 130.8 parts by weight of ethyl acid phosphate (mixing weight ratio of monoester to diester is 45:55) as raw materials for catalyst preparation Except for using 529.5 parts by weight of tetra-n-butyl titanate, the same procedure as in Example 2 was followed until the concentration operation to obtain a catalyst as a viscous liquid before pulverization. Furthermore, this liquid catalyst was dissolved in 1,4-butanediol to prepare a titanium atom content of 33,600 ppm. The storage stability in 1,4-butanediol was good, and the catalyst solution stored at 40 ° C. under a nitrogen atmosphere did not show the formation of precipitates for at least 40 days. The catalyst solution had a pH of 6.3.
[Production of aliphatic polyester resin]
A polymer was obtained in the same manner as in Example 2 except that the above catalyst was used. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Example 10]
[Preparation of catalyst for polycondensation]
As raw materials for catalyst preparation, 105.8 parts of magnesium acetate tetrahydrate, 1,500 parts of ethanol, and ethyl acid phosphate (mixing weight ratio of monoester to diester is 45:55) are 105.8. Except that 32 parts by weight of tetra-n-butyl titanate was used, a concentration operation was performed in the same manner as in Example 2 to obtain a catalyst as a viscous liquid before pulverization. Further, this liquid catalyst was dissolved in 1,4-butanediol to prepare a titanium atom content of 33,300 ppm. The storage stability in 1,4-butanediol was good, and the catalyst solution stored at 40 ° C. under a nitrogen atmosphere did not show the formation of precipitates for at least 40 days. The catalyst solution had a pH of 6.2.
[Production of aliphatic polyester resin]
A polymer was obtained in the same manner as in Example 2 except that the above catalyst was used. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Example 11]
[Preparation of catalyst for polycondensation]
As a raw material for catalyst preparation, 129.6 mg of magnesium acetate tetrahydrate, 2,000 parts by weight of ethanol, and ethyl acid phosphate (mixing weight ratio of monoester to diester is 45:55) Except for using 789.1 parts by weight of tetra-n-butyl titanate, the catalyst was obtained as a viscous liquid before pulverization by carrying out the concentration operation in the same manner as in Example 2. Further, this liquid catalyst was dissolved in 1,4-butanediol to prepare a titanium atom content of 36,000 ppm. The storage stability in 1,4-butanediol was good, and the catalyst solution stored at 40 ° C. under a nitrogen atmosphere did not show the formation of precipitates for at least 40 days. The catalyst solution had a pH of 6.2.
[Production of aliphatic polyester resin]
A polymer was obtained in the same manner as in Example 2 except that the above catalyst was used. Table 1 shows the polymerization time and the physical properties of the obtained polymer.

[Example 12]
[Production of aliphatic polyester resin]
The esterification step shown in FIG. 1 and the polycondensation step shown in FIG. 2 were performed to produce an aliphatic polyester resin as follows. First, a slurry at 60 ° C. mixed at a ratio of 1.30 moles of 1,4-butanediol and 0.0033 moles of malic acid to 1.00 moles of succinic acid from the slurry preparation tank to the raw material supply line (1) Then, it was continuously fed to a reactor (A) for esterification having a screw type stirrer filled with an aliphatic polyester resin oligomer having an esterification rate of 99% by weight so as to be 42 kg / h. At the same time, the bottom component of the rectifying column (C) at 100 ° C. (98% by weight or more was 1,4-butanediol) was supplied at 3.0 kg / h from the recirculation line (2).

  The reactor (A) is set to an internal temperature of 230 ° C. and a pressure of 101 kPa, and water, tetrahydrofuran and excess 1,4-butanediol produced are distilled from the distillation line (5) and high in the rectification column (C). Separated into boiling and low boiling components. A part of the high-boiling component at the bottom of the column after the system was stabilized was extracted to the outside through an extraction line (8) so that the liquid level of the rectification column (C) was constant. On the other hand, a low boiling component mainly composed of water and tetrahydrofuran is extracted from the top of the tower in the form of gas, condensed in a condenser (G), and the extraction line (13) so that the liquid level in the tank (F) becomes constant. ) Extracted outside.

  A certain amount of the oligomer generated in the reactor (A) is extracted from the oligomer extraction line (4) using the pump (B), and the average residence time in terms of succinic acid unit of the liquid in the reactor (A). The liquid level was controlled so as to be 3 hours. The oligomer extracted from the extraction line (4) was continuously supplied to the first polycondensation reactor (a). After the system was stabilized, the esterification rate of the oligomer collected at the outlet of the reactor (A) was 90.6%.

  The catalyst solution prepared in advance by the above-described method is supplied to the 1,4-butanediol line (L8) through the supply line (L7), and further into the oligomer extraction line (4) as a lower concentration solution. It supplied so that it might become 0 kg / h. The concentration as titanium atoms at the time of supply to the line (4) was 0.17% by weight, and the supply amount was stable for 24 hours or more.

  The internal temperature of the first polycondensation reactor (a) was 250 ° C., the pressure was 2.7 kPa, and the liquid level was controlled so that the residence time was 120 minutes. An initial polycondensation reaction was performed while extracting water, tetrahydrofuran, and 1,4-butanediol from a vent line (L2) connected to a decompressor (not shown). The extracted reaction liquid was continuously supplied to the second polycondensation reactor (d).

  The second polycondensation reactor (d) has an internal temperature of 250 ° C. and a pressure of 400 Pa. The liquid level is controlled so that the residence time is 60 minutes, and a vent line (not shown) connected to a decompressor (not shown) The polycondensation reaction was further advanced while extracting water, tetrahydrofuran and 1,4-butanediol from L4). The obtained polymer was continuously supplied to the third polycondensation reactor (k) via the extraction line (L3) by the extraction gear pump (e). The internal temperature of the third polycondensation reactor (k) was 250 ° C., the pressure was 130 Pa, the residence time was 60 minutes, and the polycondensation reaction was further advanced. The obtained polymer was continuously extracted in the form of a strand from the die head (g) and cut with a rotary cutter (h). The obtained aliphatic polyester resin had a reduced viscosity of 2.59, a terminal carboxyl group concentration of 21 μeq / g, excellent color tone and transparency, and few foreign matters. The results are shown in Table 1.

  According to the present invention, an industrially advantageous and efficient production method has sufficient tensile properties by using a catalyst in which a titanium compound, an alkaline earth metal compound and a phosphorus compound are mixed in advance as a catalyst. An aliphatic polyester having a high degree of polymerization can be easily produced. Furthermore, since the polyester of the present invention reduces thermal decomposition and thermal degradation of the polyester due to the residual catalyst in the polyester, mechanical properties such as moldability by injection molding, hollow molding and extrusion molding, thermal stability and tensile properties, etc. It is an excellent polyester.

Explanatory drawing of an example of the esterification reaction process employ | adopted by this invention Explanatory drawing of an example of the polycondensation step employed in the present invention

Explanation of symbols

1: Raw material supply line
2: Recirculation line
3: Esterification tank catalyst supply line
4: Oligomer extraction line
5: Distillation line
6: Extraction line
7: Circulation line
8: Extraction line
9: Gas extraction line
10: Condensate line
11: Extraction line
12: Circulation line
13: Extraction line
14: Vent line
15: Supply line
A: Reactor
B: Extraction pump
C: Rectification tower
D, E: Pump
F: Tank
G: Capacitor
L1, L3: Extraction line
L2, L4, L6: Vent line
L5: Polymer extraction line
L8: 1,4-butanediol supply line
L7: Catalyst supply line
a: First polycondensation reactor
d: Second polycondensation reactor
k: Third polycondensation reactor
c, e, m: gear pump for extraction
g: Dice head
h: Rotary cutter
p, q, r, s: filter

Claims (7)

  Production of an aliphatic polyester characterized in that, in producing a polyester having an aliphatic diol unit and an aliphatic dicarboxylic acid unit, a catalyst prepared by previously mixing a titanium compound, an alkaline earth metal compound and a phosphorus compound is used as a catalyst. Method.   The method for producing an aliphatic polyester according to claim 1, wherein the alkaline earth metal compound is an organic acid salt of alkaline earth metal and / or a hydrate thereof.   The method for producing an aliphatic polyester according to claim 1, wherein the alkaline earth metal is magnesium.   The manufacturing method of the aliphatic polyester in any one of Claims 1-3 whose phosphorus compound is an acidic phosphate compound.   The fat according to any one of claims 1 to 4, wherein a catalyst obtained by mixing an alcohol, a titanium compound, an alkaline earth metal compound, and an acidic phosphate compound and concentrating the mixture is used. A method for producing a group polyester. The catalyst is a catalyst for polyester polymerization containing a titanium atom, an alkaline earth metal atom and a phosphorus atom, and the content T (molar basis) of titanium atom and the content P (molar basis) of phosphorus atom in the catalyst are The method for producing an aliphatic polyester according to any one of claims 1 to 5, wherein the catalyst satisfies the following formula (1).
0.5 ≦ T / P (molar ratio) ≦ 5.5 (1) The catalyst is a catalyst for polyester polymerization containing a titanium atom, an alkaline earth metal atom and a phosphorus atom, and the alkaline earth metal content M (molar basis) and the phosphorus atom content P (molar basis) are: It is a catalyst which satisfies following formula (2), The manufacturing method of the aliphatic polyester in any one of Claims 1-6 characterized by the above-mentioned.
0.5 ≦ M / P (molar ratio) ≦ 3.0 (2)

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