WO2006001084A1

WO2006001084A1 - Process for producing aliphatic polyester

Info

Publication number: WO2006001084A1
Application number: PCT/JP2004/009497
Authority: WO
Inventors: Hisashi Nogami; Yasushi Ichikawa; Takashi Nakauma
Original assignee: Showa Highpolymer Co., Ltd.
Priority date: 2004-06-29
Filing date: 2004-06-29
Publication date: 2006-01-05
Also published as: JPWO2006001084A1; JP4680909B2

Abstract

A process for producing an aliphatic polyester giving fibers, films, sheets, and other moldings in which the surface deposit derived from cyclic oligomers has been diminished to an amount which is not practically problematic. These moldings hence have an excellent appearance and do not arouse a trouble in subsequent processing or during use in applications. The process can minimize the production cost. The process comprises reacting an aliphatic polybasic acid or derivative thereof with an aliphatic polyhydric alcohol to produce an aliphatic polyester, and is characterized in that a phosphorus compound is added to and mixed with the reactants in an amount of 3.0 to 3.0×103 mol per mol of a catalyst to thereby reduce the content of cyclic oligomers in the aliphatic polyester.

Description

Process for producing aliphatic polyester Technical Field

The present invention is a method for producing an aliphatic polyester, and by adding and mixing a phosphorus compound in the method, the production of a cyclic oligomer as a by-product is effectively suppressed, and the cyclic oligomer content is reduced. The present invention relates to a method for producing a low aliphatic polyester. Akita

Background art

Aliphatic polyesters typified by polybutylene succinate are widely used after being processed into products such as agricultural materials, civil engineering materials, vegetation materials, and packaging materials because of their good physical properties and biodegradability. Particularly in recent years, application to food packaging materials is expected. .

However, the above-mentioned aliphatic polyester by-produces a low molecular weight oligomer during the polymerization process, and when it is left to stand for a long time after being molded into a film or the like, the oligomer (in particular, a cyclic dimer) moves to the molded product surface. It was revealed that the appearance characteristics deteriorated.

Such precipitation of cyclic oligomers is known, for example, in polyethylene terephthalate (PET), which is not an aliphatic polyester (J. P o 1 ymer S ci., 1954, vol. 1 3 , Pp. 40, 6), it has been confirmed that surface precipitates are mainly cyclic trimers. Cyclic trimers have a large molecular weight and are difficult to physically remove from PET by pressure reduction. On the other hand, as a method for obtaining a high molecular weight PET having a low content of cyclic oligomers such as cyclic trimers, a solid phase polymerization method at a temperature below the melting point has been put into practical use. According to this method, it is known that the content of cyclic trimer in PET can be reduced to about 0.3% by weight.

However, in general, aliphatic polyesters have a low melting point unlike PET and cannot be used in PET because they cannot secure a practical polymerization temperature for solid-phase polymerization. The solid phase polymerization method is not applicable to aliphatic polyesters.

In Japanese Patent Application Laid-Open No. 0-7-3 1 6 2 7 6, a high molecular weight aliphatic polyester is added to pure water, pure water and alcohol, or pure alcohol in the state of powder, pellets, or a molded article. A method has been devised in which the residual monomers and oligomers are eluted and removed by contacting them at a temperature lower than the melting point of the molecular weight aliphatic polyester and lower than the boiling point of these solvents.

Further, in Japanese Patent Application Laid-Open No. 2000-002, the aliphatic polyester is obtained from an aliphatic ketone, an alicyclic ether, and an aliphatic monoester in the state of a powder, a pellet, or a molded product. A method has been devised in which one or more selected solvents are contacted at a temperature lower than the melting point of the aliphatic polyester and lower than the boiling point of the solvent, and the residual monomers and oligomers are eluted and removed. Yes.

However, these methods are not efficient because they increase the number of solvent cleaning steps and cleaning solvent removal steps, and are costly in terms of capital investment.

On the other hand, a method for reducing cyclic oligomers in biodegradable aliphatic polyester carbonate is disclosed in Japanese Patent Application Laid-Open No. 08-301099. In other words, this method is intended for cyclic oligomers mainly composed of cyclic dimers consisting of succinic acid and 1,4-butanediol (reactions of each of the two molecules). The biodegradable aliphatic polyester carbonate After completion of the polycondensation reaction, a phosphorus compound is added and mixed to suppress ester exchange and polycondensation reaction, and then degassing under reduced pressure at a temperature above the melting point of the biodegradable aliphatic polyester carbonate. And removing the cyclic oligomer from the biodegradable aliphatic polyester carbonate. However, in this method, the degassing step of the cyclic oligomer is increased, and further, the cyclic oligomer is regenerated during the degassing treatment because the ring chain equilibrium of the cyclic oligomer is not sufficiently suppressed. In order to compensate for this drawback, it is necessary to use a special degassing device that can obtain a high degassing removal rate, which increases the burden on the capital investment, and the removed cyclic oligomer removes the degassing. There are many equipment problems such as the equipment's decompression system being blocked, which is not efficient in terms of capital investment. Disclosure of the invention

The present invention has excellent thermal stability when an aliphatic polyester is formed into a fiber, film, sheet, or other molded article, and surface precipitation derived from a cyclic oligomer contained in the aliphatic polyester. The purpose of the present invention is to provide a method for producing an aliphatic polyester that is reduced to an amount that does not cause a problem in practical use, has excellent appearance characteristics, has no hindrance in post-processing and application fields, and can reduce production costs as much as possible. To do. As a result of intensive studies, the present inventors have found that the above object can be achieved by adding and mixing a phosphorus compound in a method for producing an aliphatic polyester, and further proceeding a polycondensation reaction. I was able to complete it.

That is, the present invention is a method for producing an aliphatic polyester by reaction of an aliphatic polybasic acid or a derivative thereof and an aliphatic polyhydric alcohol, in which the phosphorus compound is added to 3 mol of the catalyst. This is a method for producing an aliphatic polyester, characterized in that the cyclic oligomer content in the aliphatic polyester is reduced by adding and mixing 0 to 3.0 X 10 ³ moles.

That is, by adding and mixing phosphorous compounds, the molecular weight of the aliphatic polyester is reduced based on the ring chain equilibrium of the cyclic oligomer by-produced during the synthesis (production) of the aliphatic polyester and the decomposition reaction of the aliphatic polyester. This is a method for producing an aliphatic polyester capable of eliminating undesirable phenomena. Brief Description of Drawings

FIG. 1 is a graph showing the relationship between the decompression time, the CD content, and the weight average molecular weight of the aliphatic polyester in Examples 1 and 2 and Comparative Example 1. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is described in detail below.

The present inventors have established a method for producing an aliphatic polyester that has excellent thermal stability, has a low cyclic oligomer content that is an obstacle in post-processing and application fields, and can reduce production costs. As a result of diligent research and various investigations, in the production method of aliphatic polyester, a phosphorus compound was added and mixed, The inventors have found that the above object can be achieved by further performing a polycondensation reaction under reduced pressure at a temperature equal to or higher than the melting point of the reester, and the present invention has been completed.

In the production method of the present invention, mainly one or more aliphatic diols and alicyclic diols and one or more aliphatic dicarboxylic acids, alicyclic dicarboxylic acids and aliphatic hydroxycarboxylic acids or anhydrides thereof. From this, an aliphatic polyester can be produced. In the production method of the present invention, the phosphorus compound is added and mixed at the above ratio, and then, under reduced pressure at a temperature equal to or higher than the melting point of the aliphatic polyester, for example, a temperature of 130 to 300 ° C. Polymerization reaction is carried out under the conditions of C and the degree of vacuum of 10 mm Hg or less until an aliphatic polyester of the required molecular weight is obtained. At the same time, the cyclic oligomer content (residual amount) in the resulting aliphatic polyester is 4 It can be 0 0 0 ppm or less.

The method for producing an aliphatic polyester according to the present invention comprises esterifying (dehydration condensation, polycondensation) of the alcohol, the carboxylic acid, the carboxylic anhydride and Z or the hydroxycarboxylic acid, and subsequently And carrying out a de-dallicol reaction in the presence of a catalyst. In this method, if necessary, a total of 3 or more aliphatic polyhydric alcohols, 3 or more aliphatic polybasic acids, their anhydrides, and alcoholic hydroxyl groups and carboxylic acid groups in one molecule. At least one aliphatic polyvalent compound selected from the group consisting of one or more aliphatic polyvalent hydroxycarboxylic acids can also be used.

Reduction of the cyclic oligomer in the method for producing an aliphatic polyester of the present invention is achieved by adding and mixing a phosphorus compound in the method. This addition and mixing of the phosphorus compound may be performed at any stage of the method. That is, during the esterification (polycondensation) reaction or after completion of the alcohol, the carboxylic acid, the carboxylic acid anhydride, and Z or the hydroxycarboxylic acid, or during or after the deglycolization reaction, This is achieved by adding and mixing an ionic compound, reacting the resulting mixture under reduced pressure, and subjecting the cyclic oligomer to ring-opening polycondensation or distillation. More specifically, a phosphorus compound is added to and mixed with a molten aliphatic polyester under a nitrogen atmosphere, followed by a polycondensation reaction under reduced pressure until the aliphatic polyester reaches the target molecular weight. The concentration of cyclic oligomers at the same time Is reduced to 4 0 0 0 ppm or less.

In the method of the present invention, since the aliphatic polyester is treated in the molten state and under reduced pressure as described above, a cyclic chain equilibrium transfer reaction, that is, a cyclic oligomer is opened in a chain and polycondensed to the aliphatic polyester. In addition, it is essential to add and mix phosphorus compounds. In other words, the addition and mixing of the phosphorus compound not only suppresses the regeneration of the cyclic oligomer, but also efficiently converts the cyclic oligomer formed in the process of esterification (polycondensation) into a cyclic chain equilibrium state with the aliphatic polyester. To polycondensation. It is also effective in improving the thermal stability of the aliphatic polyester in the molten state. The addition amount of the phosphorus compound is in the range of 3.0 to 3.0 X 10 ³ times mol, preferably 10 to 10 ² times mol, per 1 mol of the catalyst.

In order to reduce the cyclic oligomer, it is preferable to carry out the reaction at a high temperature and a high degree of vacuum, and the reaction temperature is 130 to 300 ° C, preferably 180 to 280 ° C. The degree of vacuum is 10 mm Hg or less, preferably 5 mm Hg or less, more preferably 2 mm Hg or less.

The reduction of the cyclic oligomer in the method for producing the aliphatic polyester of the present invention may be continued in the apparatus used for esterification (polycondensation) of the aliphatic polyester, or may be performed using a separately prepared apparatus. Is possible. In the method of the present invention, the aliphatic polyester is melted, and it is not necessary to consider (re) generation of the cyclic oligomer after the addition and mixing of the phosphorus compound. Therefore, it is not necessary to use an apparatus that can obtain a particularly high removal rate of the cyclic oligomer. However, in order to efficiently increase the molecular weight of the aliphatic polyester to the required value, a device with high surface renewability and capable of heating and depressurization is preferable. For example, a normal high viscosity solution stirring device is provided. A tank reactor can be used. Examples of the high-viscosity solution stirring device include those using a lattice blade, a helical ribbon blade, a mouth gbone blade, and the like.

The molecular weight of the aliphatic polyester can be increased by further reacting the produced aliphatic polyester with a polyvalent isocyanate compound.

When the aliphatic polyester is reacted as a prepolymer with the polyvalent isocyanate compound, the ratio is 0.1 to 5 parts by weight of the polyvalent isocyanate compound with respect to 100 parts by weight of the aliphatic polyester. The aliphatic polyester (pre- The number average molecular weight of the polymer) is 5,000 or more, desirably 10 0,000 or more, and the weight average molecular weight is 30,000 or more, desirably 34,000 or more. The number average molecular weight is less than 5,00 ° or the weight average molecular weight is less than 30,000, or the number average molecular weight is less than 5,000 and the weight average molecular weight is less than 30,000. In order to give the desired physical properties to the finally obtained aliphatic polyester, it is necessary to increase the amount of the polyisocyanate compound used, which is gelled during melt mixing with the prepolymer. This is not preferable because it significantly increases the risk of the above.

When the amount of the polyvalent isocyanate compound used is too small, the molecular weight of the aliphatic polyester does not increase efficiently, which is not preferable.

Specific examples of polyvalent isocyanate compounds include, for example, a mixture of 2,4_tolylene socyanate, 2,4—tolylene socyanate and 2,6—tolylene socyanate, Examples include, but are not limited to, diphenylmethane isocyanate, 1,5-naphthylenediocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, and isophorone disiocyanate. . Of these, hexamethylene diisocyanate is particularly preferred from the viewpoint of the hue and reactivity of the aliphatic polyester produced.

Examples of the aliphatic diol or alicyclic diol include the following types. Echi Rengrikol, 1, 3-prono. 1,4--butanediol, 1,6-hexanediol, nonamethyleneglycol, decamethyleneglycol, propylene glycol, 1,3-butanediol, 2-methylprononediol, 1,3 neopentyl Glycol, 1,4-sucrose hexanedimethanol. Among these dinoles, ethylene glycolate, 1,4-butanediole and 1,4-cyclohexanedimethanol increase the melting point of the resulting aliphatic polyester and impart biodegradability to the aliphatic polyester. However, it is preferable in order to ensure the same moldability as that of the polyolefin-polyolefin.

Furthermore, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aliphatic hydroxycarboxylic acids or their anhydrides for esterification with the above aliphatic diols or alicyclic diols include, for example, succinic acid. Acid, succinic anhydride, adipic acid, none Water adipic acid, suberic acid, sebacic acid, dodecanedioic acid, cyclohexanedicarboxylic acid and the like. Among these, the use of succinic acid, succinic anhydride, adipic acid, suberic acid, sebacic acid and dodecanedioic acid increases the melting point of the resulting aliphatic polyester, similar to the preferred diol, This is preferable for imparting biodegradability to the aliphatic polyester and ensuring the same moldability as that of the polyolefin of the aliphatic polyester.

Particularly preferred combinations of aliphatic diols or alicyclic diols with aliphatic dicarboxylic acids, alicyclic dicarboxylic acids and aliphatic hydroxycarboxylic acids or their anhydrides are ethylene glycol and succinic acid, 1 1,4-butanediol and succinic acid, 1,4-butanediol and succinic acid and sebacic acid, 1,4-cyclohexanedimethanol and adipic acid, 1,4-cyclohexanedimethanol monoleole and sepacic acid. The combination is preferable for increasing the melting point of the resulting aliphatic polyester, imparting biodegradability to the aliphatic polyester, and ensuring the same moldability as the polyolefin of the aliphatic polyester.

Use ratio of aliphatic diol or alicyclic diol and aliphatic dicarboxylic acid, alicyclic dicarboxylic acid and aliphatic hydroxyl carboxylic acid or their anhydride is aliphatic dicarboxylic acid, alicyclic dicarboxylic acid In addition, an aliphatic diol or an alicyclic diol in an amount of 1.0 to 1.2 mol is preferable with respect to 1 mol of an aliphatic hydroxycarboxylic acid or an anhydride thereof.

The (polydegradable high molecular weight) aliphatic polyester produced by the production method of the present invention is a trivalent or higher aliphatic polyhydric alcohol within the range that does not impair the object of the present invention during the esterification reaction, trivalent By using at least one kind of polyvalent aliphatic compound selected from the group consisting of the above aliphatic polybasic acids or derivatives thereof, for example, a branch is introduced into the molecule of the aliphatic polyester and the molecular weight thereof is introduced. As a result, the aliphatic polyester can be molded into films and sheets having excellent physical properties.

Examples of trihydric or higher aliphatic polyhydric alcohols include glycerin, trimethylol propane, pentaerythritol, triaryl isocyanurate ethylene oxide adduct, and the like. It also removes glycerin, an aliphatic trihydric alcohol. Glycidol, a monoepoxy compound in water form, can also be used.

Commercially available aliphatic polyvalent hydroxycarboxylic acids and their anhydrides with a total of 3 or more alcoholic hydroxyl groups and carboxylic acid groups in one molecule are available, but they are available at low cost. From the standpoint of being able to be produced, phosphonic acid, tartaric acid and citrate are preferred.

In the method for producing an aliphatic polyester of the present invention, a tribasic or higher polybasic acid anhydride may be added. Examples thereof include trimesic acid, propanetricarboxylic acid, and trimellitic anhydride. Examples thereof include tartic acid, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, cyclopentatetracarboxylic anhydride, and the like. Of these, trimellitic anhydride and pyromellitic anhydride are particularly preferable.

Each component of the polyvalent aliphatic compound can be mixed and used as necessary. The amount of the polyvalent aliphatic compound used is a total of 0.1 to 0.1 mol% of the aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, and aliphatic hydroxycarboxylic acid or their anhydride components. It is 5 mol% and can be added from the beginning of the esterification reaction.

The method for producing an aliphatic polyester of the present invention includes an esterification reaction using the alcohol, the carboxylic acid, the carboxylic anhydride and / or the hydroxycarboxylic acid, and a deglycol reaction.

In the method for producing an aliphatic polyester of the present invention, the esterification reaction is first performed. The esterification reaction can be carried out in an inert gas atmosphere at 13 to 30 ° C., preferably at 16 to 25 ° C. for 5 to 16 hours. If the temperature is lower than 130 ° C, the reaction rate is slow and the practicality is poor. Also, at a temperature higher than 300 ° C, the risk of decomposition of the aliphatic polyester increases and should be avoided. Therefore, it is preferable to carry out the esterification reaction as the first step at a temperature between 180 ° C. and 220 ° C. The esterification reaction is carried out until the acid value of the aliphatic polyester reaches 30 or less, preferably 15 or less, and more preferably 10 or less. In this case, the higher the molecular weight of the aliphatic polyester, the more smoothly the molecular weight can be increased by the subsequent deglycol reaction. Therefore, it is desirable to obtain a higher molecular weight aliphatic polyester. The subsequent deglycolation reaction is carried out at a pressure of 5 Torr or less from 1 70 to 2 30 ° C. At 2 to 16 hours. More preferably, it is preferably carried out at 180 to 210 ° C. under a high vacuum of 1 Torr or less from the viewpoint of reaction rate and prevention of decomposition of the aliphatic polyester. The resulting aliphatic polyester has substantially all hydroxyl groups at the end groups and has an acid value of substantially zero.

In the present invention, a deglycolization reaction is performed subsequent to the esterification reaction, and the number average molecular weight of the aliphatic polyester obtained by the esterification reaction is 5 000 or more, or the weight average molecular weight is 3 0, 0 0 The number average molecular weight needs to be 0 or more, preferably 5 or more, and the weight average molecular weight needs to be 30 or more, but in order to do so, a catalyst must be used. Examples of these are organics of at least one metal selected from the group consisting of titanium, tin, antimony, cerium, germanium, zinc, cobalt, manganese, iron, aluminum, magnesium, calcium and strontium. Or an inorganic metal compound is mentioned, The usage-amount is 0.001 to 0.5 weight part with respect to 100 weight part of produced | generated aliphatic polyester. If the amount of these catalysts used is less than 0.01 part by weight, the deglycolization reaction becomes slow and impractical, and if used in excess of 0.5 part by weight, the decomposition reaction of the aliphatic polyester is strengthened. As a result, it is not preferable. The desired amount used varies depending on the type of metal, but is from 0.05 to 0.2 parts by weight. As these catalysts, for example, metal alkoxides, organic acid salts, chelates, oxides, etc. are used, and in particular, organometallic compounds of titanium, such as alkyl titanates, titanium oxyacetyl acetate, titanium oxalate. Compounds such as are useful. Aliphatic polyesters, so-called biodegradable polyesters, are subject to microbial degradation in the soil, but these catalysts appear to remain in the soil and must be a safe type of metal compound. From this point of view, desirable metal compounds include compounds such as titanium, germanium, zinc, magnesium, and calcium.

Furthermore, one of the characteristics of the present invention is that after the deglycolization reaction is completed, a desired amount of a polyvalent isocyanate compound is added to the aliphatic polyester obtained after the dedallicol reaction in a molten state. The number average molecular * of the polyester is 10 0, 0 0 0 or more, or the weight average molecular weight is 50, 0 0 0 or more, or the number average molecular weight is 1 0, 0 0 0 or more and the weight average molecular weight is 5 0, 0 0 0 This is what you can do. Aliphatic poly Regarding the melt viscosity of esters, the weight average molecular weight contributes more than the number average. For example, in film molding and the like, if the number average molecular weight is the same level but the weight average molecular weight is different, the moldability is different and it is desirable that the weight average molecular weight is as large as possible. This is the reason why the weight average molecular weight is specified in the present invention. In the production method of the present invention, at any stage, that is, during or after the esterification reaction, during or after the deglycolation reaction, or during or after the reaction using the isocyanate, It has one feature in adding and mixing compounds. For example, as described above, a phosphorus compound can be added and mixed during the esterification (polycondensation) reaction of the aliphatic polyester. The phosphorus compound is thought to act as a catalyst for the ring-opening polymerization reaction, and actually has an effect of reducing cyclic oligomers. Examples of the phosphorus compound used in the method of the present invention include the following types.

(a) Phosphoric acid and its alkyl esters: Commercially available trimethyl phosphates such as trimethyl phosphate, triethyl phosphate, tributynophosphate, trioctyl phosphate, tridecyl Norephosphate, alkyl acid phosphates (alkyl groups are methyl, isopropyl, butyl, octyl, etc.).

(b) Phosphonic acid organic esters: Examples of commercially available products include dibutyl butyrate phosphonate.

(c) Phosphorous acid: When used alone or in combination with other phosphorus compounds, excellent ring-opening efficiency for cyclic oligomers and strong hue stabilizing effect for aliphatic polyesters are observed.

(d) Phosphite organic esters: For example, dibutyl hydrogen phosphate is commercially available and can be used in the present invention. Other examples include triphenyl phosphite, diphenyl sodecyl phosphite, phenyl diisodecyl phosphite, tris (mono or dinonyl phenyl) phosphite, trisisodecyl phosphite, and the like.

(e) Other inorganic phosphorus compounds: Examples include polyphosphoric acid.

Since commercially available phosphoric acid mostly contains water, polyphosphoric acid is better. The aliphatic polyester has practical value without causing molecular weight reduction. Nilin pentoxide can also be used, but it is difficult to handle due to its strong hygroscopicity. In the case of producing polyolefins and the like, if inorganic phosphorus compounds such as phosphoric acid and phosphorous acid are used as they are, there is a difficulty in homogeneous mixing in terms of miscibility, but in the case of producing aliphatic polyesters. Even if attention is paid to the moisture contained in the phosphorus compound, it can be added and mixed at a high temperature as it is. Among the phosphorous compounds mentioned above, phosphorous acid and phosphorous acid organic esters show excellent effects and are sufficient for the purpose of the present invention. Therefore, the present invention will be described mainly.

The amount of the phosphorus compound used in the method of the present invention varies depending on the type and amount of catalyst used in the de-dallicol reaction, but is 3.0 to 3.0 X 10 ³ times moles per mole of catalyst. More preferably, it is 10 to 10 ² times mole. This is because if the amount is less than 3.0 times mol, the above effects are hardly exhibited. Moreover, even if it exceeds 3.0 X 10 ³ times mol, it is because there is no effect of increasing the amount and it is economically disadvantageous. Phosphorous compounds such as phosphorous acid are added to the aliphatic polyester, which is a prepolymer melted at a temperature of 130 ° C. or more and 300 ° C. or less.

The number average molecular weight obtained by the present invention is 10, 000 or more, or the weight average molecular weight is 50, 000 or more, or the number average molecular weight is 10, 000 or more and the weight average molecular weight is 50 , 000 or more high molecular weight aliphatic polyesters are biodegradable in natural soil and water, and depending on the composition, they are highly biodegradable until the original form disappears in about 3 months to 1 year. It is a molecular weight aliphatic polyester. Of course, the biodegradable high molecular weight aliphatic polyester obtained by the present invention can be used in combination with organic or inorganic fillers, reinforcing agents, stabilizers, lubricants, oligomers, polymers, and the like. Example

Hereinafter, the present invention will be described in more detail with reference to examples. The measurement method used in this example is first described below. In addition, as an index of the cyclic oligomer content (residual amount) in the aliphatic polyester, the concentration of the cyclic dimer (cyclodimer, CD) which is a causative substance of the bleed is described as a representative value. Means to measure this and Gas chromatographic analysis was used.

[Gas chromatographic analysis]

Model used: G C — 14 B manufactured by Shimadzu Corporation was used.

1 20 μ πι Press. Film: Molding temperature 1800 ° C, preheating 1 minute, pressurizing at 1 50 Kg / cm ^{2 and} pressing for 30 seconds, immersed in THF for 2 4 hours Then, CD in the extract (THF) was quantified.

The weight average molecular weight (hereinafter referred to as “Mw”) was analyzed using gel chromatography.

[Gel chromatography]

Model used: Showa Denko Co., Ltd., and measured using the following method under the following conditions, using SHODEEX GPSCystem-11.

Solvent: Hexafluoroisopropyl pill alcohol containing ammonium acetate 15 mm o 1/1 was used.

Aliphatic polyester concentration in the solution: 0.1 mass%.

Calibration curve: A PMMA standard sample (Sho d ex St a n d a d M — 75) manufactured by Showa Denko KK was used.

(Example 1)

The reactor 7 0 l after nitrogen substitution, 1, 4 one-butanediol 1 6. 0 3 K g ( 1 0 5 mole ^_0/0) Oyopi succinate 2 0. 0 K g (1 0 0 mole ^_0/0) were charged. Subsequently, 3.58 g of catalyst tetraisopropoxytitanium was also added in advance. The temperature was raised under nitrogen flow for 4.5 hours at 140-220 ° C, and further nitrogen was stopped for 1.5 hours under a reduced pressure of 260-260 ° Pa. Esterification reaction by dehydration condensation was performed. The produced aliphatic polyester had an acid value of 20 mg K0HZ g, a number average molecular weight (Mn) of 4,800 and a weight average molecular weight (Mw) of 12,8 70.

Subsequently, the temperature was set to 2 15 to 20 ° C., and the vacuum was adjusted to 2.0 to 0.3 mm Hg with a vacuum pump, and deglycolization reaction was performed for 1.5 hours. The resulting aliphatic polyester (0 — A) has a number average molecular weight (Mn) of 2,3,00,0, a weight average molecular weight (Mw) of 4,4,00,0 and a cyclodimer (CD) content of 9 , 3 0 0 ppm I got it.

Subsequently had by the addition of normal pressures under nitrogen stream phosphite 2 9. 1 6 g (2 1. 0 X 1 0- 4 mol against 1 mol starting material succinate). The reaction was carried out for 1.5 hours at a temperature of 240 to 245 ° C and a reduced pressure of 2.0 to 0.3 mmHg using a vacuum pump. The resulting aliphatic polyester (0-B) had Mn of 24, 00, Mw of 78, 00, and CD content of 4,500 ppm.

Further, the reaction was performed at 240 to 245 ° C under reduced pressure of 2.0 to 0.3 mmHg for 2 hours. Mn of the obtained aliphatic polyester (0—C) was 3 3, 0 0 0, M w was 1 3 4, 0 0 0, and 0 content was 1, 8 0 0 pp m.

(Example 2)

Except that the added mixture of phosphorous acid and (2 1 0 X 1 0- ⁴ mol relative to the starting material of succinic acid 1 mol), under the same conditions as in Example 1, the esterification reaction Contact Yopi deglycol reaction I did it.

In the aliphatic polyester (2-A) immediately before the addition of phosphorous acid: ^ 11 was 2 3, 2 0 0, Mw was 4 5, 0 0 0, and the CD content was 9 5 0 0 pp m.

Subsequently, phosphorous acid was added and mixed, the temperature was adjusted to 240-245 ° C, and the reaction was carried out for 1.5 hours under reduced pressure of 2.0-0.3 mmHg using a vacuum pump. The resulting aliphatic polyester (2-B) had an Mn of 24,00, 0, Mw of 81,00, and a CD content of 4,20 Op.

Further, the reaction was carried out at 240 to 245 ° C. under reduced pressure of 2.0 to 0.3 mmHg for 2 hours. The obtained aliphatic polyester (2-C) had Mn of 33, 00, Mw of 1556, 00, and CD content of 1400 ppm.

(Comparative Example 1)

Except that the added mixture of phosphorous acid and (1 0. 5 X 1 0- ⁴ mol relative to the starting material of succinic acid 1 mol), under the same conditions as in Example 1, the esterification reaction Contact Yopi deglycol The reaction took place.

The Mn of the aliphatic polyester (1—A) immediately before the addition of phosphorous acid was 23, 20.00, M ^ 42, 00, and the CD content was 9400 ppm.

Next, add phosphorous acid and mix to a temperature of 240 to 245 ° C. The reaction was carried out for 1.5 hours under reduced pressure of 2.0 to 0.3 mmHg. Mn of the obtained aliphatic polyester (1-B) was 2 3, 0 0 0,] \ 4 ^ was 44, 0 0 0, and CD content was 6, 8 0 0 ppm.

Further, the reaction was carried out at 240 to 245 ° C. under reduced pressure of 2.0 to 0.3 mm Hg for 2 hours. Mn of the obtained aliphatic polyester (1 1 C) was 24,000, Mw was 51,000, and the CD content was 5800 ppm.

FIG. 1 shows the relationship between the time of reduced pressure, the CD content, and the weight average molecular weight of the aliphatic polyester in Examples 1 and 2 and Comparative Example 1. In Examples 1 and 2 of the present invention, it was found that the CD content rapidly decreased with the increase of the decompression time and the progress, and the weight average molecular weight of the aliphatic polyester increased at an accelerated rate.

On the other hand, in Comparative Example 1, the decrease in the CD content was slight compared to the examples of the present invention, and it can be said that the weight average molecular weight of the aliphatic polyester hardly increased.

As can be seen from the above, it has been found that an aliphatic polyester having a CD content of not more than 400 ppm can be produced by the production method of the present invention. Such CD content is sufficiently low for the aliphatic polyester to have various physical properties such as good appearance characteristics.

The CD content in the aliphatic polyesters of the present invention obtained in the examples was 4 000 ppm or less, whereas in the comparative examples, the CD content was higher than 4 O O O p pm.

In addition, while the aliphatic polyester having a sufficiently large weight average molecular weight could be efficiently produced by the production method of the present invention, in the comparative example, the weight average molecular weight of the aliphatic polyester hardly increased and a large weight was obtained. The average molecular weight could not be obtained efficiently.

The aliphatic polyester obtained by the production method of the present invention was found to have a sufficiently large weight average molecular weight to have various good physical properties such as thermal stability, post-processing and other various uses. .

Claims

The scope of the claims

1. A method for producing an aliphatic polyester by reacting an aliphatic polybasic acid or a derivative thereof with an aliphatic polyhydric alcohol, in which a phosphorus compound is added

The cyclic dimer content in the aliphatic polyester is reduced by adding and mixing 3.0 to 3.0 X 10 ³ moles with respect to 1 mole of the catalyst. Production method.

2. The aliphatic polybasic acid or derivative thereof is at least one selected from aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, aliphatic hydroxycarboxylic acid or anhydride thereof, The polyhydric alcohol is at least one selected from aliphatic diols and alicyclic diols, and after adding and mixing the phosphorus compound, the temperature is 130 to 300 ° C. and the degree of vacuum is 10 mmH g or less. Under the conditions, a polycondensation reaction is performed until an aliphatic polyester having a required molecular weight is obtained, and the content of the cyclic dimer in the resulting aliphatic polyester is 4 OOO ppm or less. Item 2. A method for producing an aliphatic polyester according to Item 1.

3. Using 100 parts by weight of the aliphatic polyester as a prepolymer, add 0.

1-5 parts by weight of a polyisocyanate compound is further reacted to make the aliphatic polyester have a number average molecular weight of 100,000 or more and / or a weight average molecular weight of 500,000 or more. The method for producing an aliphatic polyester according to claim 1 or 2, wherein:

4. The aliphatic polyester according to any one of claims 1 to 3, comprising a trihydric or higher polyhydric alcohol and a tribasic or higher polybasic acid as auxiliary components of the aliphatic polyester or the prepolymer. Production method.

5. The polyhydric alcohol is ethylene glycol, 1,4-monobutanediol, 1,6-hexanediol, decamethylene glycol as an aliphatic diol unit. Neopentinoreguli Cornole Oppi 1,4-sucrose hexanedimethanolone unit, and the polybasic acid or a derivative thereof is succinic acid as an aliphatic dicarboxylic acid unit, The method for producing an aliphatic polyester according to any one of claims 1 to 4, which has a unit selected from the group consisting of adipic acid, suberic acid, sebacic acid and dodecanoic acid units.

6. The method for producing an aliphatic polyester according to claim 4, wherein the trihydric or higher polyhydric alcohol is at least one selected from the group consisting of trimethylolpropane, glycerin and pentaerythritol.

7. The method for producing an aliphatic polyester according to claim 4, wherein the aliphatic hydroxycarboxylic acid is at least one selected from the group consisting of malic acid and oxalic acid tartaric acid.

8. The aliphatic polyester or the prepolymer may be trimesic acid, propanetricarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride as a trivalent or tetravalent polybasic acid. The method for producing an aliphatic polyester according to any one of claims 1 to 7, further comprising at least one selected from the group consisting of a product and a cyclopentanetetracarboxylic anhydride.

9. The method for producing an aliphatic polyester according to claim 1, wherein the phosphorus compound is phosphorous acid.