JP2006265503A - Method for producing aliphatic polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for industrially advantageously producing an aliphatic polyester having an excellent hue, a small amount of foreign matter and high appearance qualities. <P>SOLUTION: In the method for producing an aliphatic polyester by esterifying and/or transesterifying an aliphatic and/or alicyclic diol component and an aliphatic and/or alicyclic dicarboxylic acid component and carrying out a polymerization reaction, the temperature of a heating medium for controlling a polymerization temperature in the polymerization reaction is in a temperature region in which the weight reduction amount of the aliphatic polyester when melted, heated and retained in a nitrogen atmosphere for 2 hours is ≤5 wt.%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an aliphatic polyester, and relates to a method for producing an aliphatic polyester having improved appearance quality such as hue and amount of foreign matter.

  In recent years, awareness of environmental protection for the earth has increased, and there has been a demand for the development of polymer materials that decompose in the natural environment. Among them, aliphatic polyesters have attracted particular attention, and are generally recognized to be biodegradable, and are expected to be used in a wide range of applications such as bottles, sheets and films. As a method for producing such an aliphatic polyester, a transesterification of an aliphatic carboxylic acid such as oxalic acid, succinic acid, or adipic acid and an aliphatic glycol such as ethylene glycol or 1,4-butanediol is performed to obtain a glycol ester and In general, a method of obtaining a low polymer thereof and then polymerizing it by heating and stirring for a long time under high vacuum is generally carried out.

For example, a method is disclosed in which a glycol component and an aliphatic dicarboxylic acid component are esterified, and the resulting polyester diol is produced in the presence of a catalyst at a temperature of 180 to 230 ° C. (see Patent Document 1). ).
In addition, 1-4 polyesters of butanediol and succinic acid or derivatives thereof are polycondensed to produce a high molecular weight polybutylene succinate efficiently at a temperature of 200 to 250 ° C. using a specific horizontal polymerization tank. Has been disclosed (see Patent Document 2).

Furthermore, when manufacturing a high molecular weight aliphatic polyester having a number average molecular weight of 10,000 to 100,000 using a high-viscosity reactor, a method for efficiently industrially manufacturing an aliphatic polyester under a temperature condition of 180 to 280 ° C. is disclosed. (See Patent Document 3).
JP-A-5-310898 JP 2002-105184 A JP-A-9-71641

However, although these documents disclose the polymerization temperature, which is a preferable condition from the viewpoint of maintaining the polymerization rate and suppressing thermal decomposition, the present inventors have actually studied, and at these polymerization temperatures, Even if the polymerization reaction is performed, the degree of polymerization is not sufficiently increased, and at the same time, the appearance quality such as the hue and the amount of foreign matter is deteriorated.
Accordingly, the present invention provides a method for producing an aliphatic polyester having an excellent hue and a low appearance amount and a high appearance quality by an industrially advantageous method.

As a result of intensive studies to solve the above problems, the present inventors have found a method for industrially advantageously producing an aliphatic polyester by setting a heating medium at a specific temperature during the polymerization reaction. The present invention has been completed.
That is, the first gist of the present invention is that an aliphatic and / or alicyclic diol component and an aliphatic and / or alicyclic dicarboxylic acid component are subjected to an esterification reaction and / or a transesterification reaction and then a polymerization reaction. In the method for producing an aliphatic polyester, the temperature of the heating medium for controlling the polymerization temperature in the polymerization reaction is set to 5 wt% when the aliphatic polyester is melted and retained for 2 hours in a nitrogen atmosphere. %, A method for producing an aliphatic polyester, characterized in that the temperature is set to a temperature range of not more than%.

  The second gist of the present invention is that the temperature of the heating medium for controlling the reaction temperature in the esterification reaction and / or the transesterification reaction is determined when the aliphatic polyester is melted and retained for 2 hours in a nitrogen atmosphere. The method for producing an aliphatic polyester described above is characterized in that the temperature reduction is set to a temperature range in which the amount of weight loss is 5 wt% or less.

  ADVANTAGE OF THE INVENTION According to this invention, the method of manufacturing industrially advantageous aliphatic polyester with the outstanding appearance quality with few foreign material amounts and high external appearance quality is provided.

Hereinafter, the present invention will be described in detail.
<Aliphatic polyester>
The aliphatic polyester contains an aliphatic and / or alicyclic diol unit and an aliphatic and / or alicyclic dicarboxylic acid unit as essential components. Preferably, the aliphatic polyester includes an aliphatic and / or alicyclic diol unit represented by the following formula (1), and an aliphatic and / or alicyclic dicarboxylic acid unit represented by the following formula (2). It is an essential component.

（上記式（１），（２）中、Ｒ¹は２価の脂肪族炭化水素基又は２価の脂環式炭化水素基
を、Ｒ²は直接結合、２価の脂肪族炭化水素基、又は２価の脂環式炭化水素基を表す。）
式（１）のジオール単位を与えるジオール成分は、炭素数が通常２以上１０以下のものであり、例えば、エチレングリコール、１，３−プロパンジオール、１，４−ブタンジオール、１，４−シクロヘキサンジメタノール等が挙げられ、中でもエチレングリコール、１，４−ブタンジオールが好ましく、１，４−ブタンジオールが特に好ましい。

(In the above formulas (1) and (2), R ¹ is a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group, R ² is a direct bond, a divalent aliphatic hydrocarbon group, Or represents a divalent alicyclic hydrocarbon group.)
The diol component that gives the diol unit of the formula (1) usually has 2 to 10 carbon atoms, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexane. Dimethanol and the like can be mentioned, among which ethylene glycol and 1,4-butanediol are preferable, and 1,4-butanediol is particularly preferable.

The dicarboxylic acid component that gives the carboxylic acid unit of the formula (2) is usually one having 2 to 10 carbon atoms, and examples thereof include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and the like. Of these, succinic acid and adipic acid are preferred.
Two or more kinds of the diol component and dicarboxylic acid component can be used.

The aliphatic polyester used in the present invention may further contain an aliphatic oxycarboxylic acid unit.
Specific examples of the aliphatic oxycarboxylic acid component that gives an aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, Examples thereof include 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, or a mixture thereof. Or these lower alkyl ester and intramolecular ester may be sufficient. In addition, when optical isomers exist in these, any of D-form, L-form, and racemate may be used, and the form may be any of solid, liquid, or aqueous solution. Among these, lactic acid or glycolic acid is preferable. These aliphatic oxycarboxylic acid components can be used alone or as a mixture of two or more.

The content of the aliphatic oxycarboxylic acid component is, in all components constituting the aliphatic polyester, the lower limit is usually 0 mol% or more, preferably 0.01 mol% or more, and the upper limit is usually 30 mol% or less. Preferably it is 20 mol% or less, More preferably, it is 10 mol% or less.
Further, the aliphatic polyester of the present invention is a tri- or higher functional aliphatic and / or alicyclic polyhydric alcohol, aliphatic and / or alicyclic polyvalent carboxylic acid or its anhydride, or aliphatic polyvalent oxycarboxylic. When an acid is contained as a copolymerization component, the melt viscosity of the resulting aliphatic polyester can be increased, which is preferable. In this case, specific examples of the trifunctional aliphatic or alicyclic polyhydric alcohol include trimethylolpropane, glycerin or its anhydride, and specific examples of the tetrafunctional aliphatic or alicyclic polyhydric alcohol. May be pentaerythritol. Specific examples of the trifunctional aliphatic or alicyclic polycarboxylic acid or its anhydride include propanetricarboxylic acid or its anhydride, and a tetrafunctional aliphatic or alicyclic polycarboxylic acid or its anhydride. Specific examples of the product include cyclopentanetetracarboxylic acid or its anhydride. In addition, the trifunctional aliphatic oxycarboxylic acid component includes (i) a type having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) one carboxyl group and two hydroxyl groups. These types are divided into types having a group in the same molecule, and any type can be used. Specifically, malic acid of type (i) can be mentioned. In addition, the tetrafunctional aliphatic oxycarboxylic acid component is composed of (i) a type having three carboxyl groups and one hydroxyl group in the same molecule, and (ii) two carboxyl groups and two hydroxyl groups. And (iii) a type having three hydroxyl groups and one carboxyl group in the same molecule, and any type can be used. Specific examples include citric acid and tartaric acid. These trifunctional or higher functional components can be used singly or in combination of two or more.

The content of such a trifunctional or higher component is, in all constituents constituting the aliphatic polyester, the lower limit is usually 0 mol% or more, preferably 0.01 mol% or more, and the upper limit is usually 5 mol% or less. Preferably, it is 2.5 mol% or less.
<Method for producing aliphatic polyester>
After the aliphatic and / or alicyclic diol component and the aliphatic and / or alicyclic dicarboxylic acid component are esterified and / or transesterified, a polymerization reaction is performed. This is a method for producing an aliphatic polyester using a heating medium as a specific temperature.

(1) Temperature of heating medium for esterification reaction and / or transesterification reaction and polymerization reaction The esterification reaction and / or transesterification reaction and polymerization reaction are usually carried out under heating conditions. However, the final polymerization tank may be cooled. In the present invention, the heating medium used in the polymerization reaction needs to satisfy the conditions described below.
(I) Kind of heating medium When manufacturing the aliphatic polyester which is this invention, a heating medium is essential.
The heating medium is not particularly limited as long as the polymerization liquid can be heated to a predetermined temperature, and an arbitrary one is used. Specifically, steam and a commercially available heat medium are mentioned.

As the heating medium used in the esterification reaction and / or transesterification reaction tank, the heating medium used in the polymerization reaction tank can be used.
In addition, the present invention is a technique that requires special attention when scaling up the production equipment, and when the polymerization tank is scaled up in a geometrically similar shape, the heat transfer area per throughput decreases, From the viewpoint of establishing a heat balance, the shape and liquid of the polymerization tank are adjusted so that the temperature of the heating medium falls within a temperature range where the weight loss of the aliphatic polyester is 5 wt% or less when melted and retained for 2 hours by nitrogenation. It is effective by adjusting the amount, depending on the case, using a preheater, installing a heating coil inside the polymerization tank, and taking out the polymerization liquid in a heat exchanger installed outside the polymerization tank and circulating it. It may be necessary to take facility measures such as enlarging and adjusting the heat transfer area. In the case of continuous polymerization, it is also effective to install a preheater in the middle of the transfer pipe. It should be noted that the temperature of the heating medium circulated through the preheater and other ancillary equipment for heating should be within a temperature range in which the weight loss amount of the aliphatic polyester when retained for 2 hours under a nitrogen atmosphere is 5 wt% or less. For example, any setting may be used, and it may be different from the temperature of the heat medium circulated in the esterification tank or the polymerization tank.

  In addition, from the beginning to the middle of the polymerization, the amount of by-products distilled out of the polymerization system is large, the liquid viscosity is relatively low, and the effect of shearing heat generation by stirring is small. In many cases, the prescription is such that the polymerization temperature is relatively high and the polymerization temperature is gradually raised as the polymerization progresses. Is often required.

On the other hand, at the latter stage of the polymerization, the distillate decreases, and the temperature rise due to the stirring shear heat generation accompanying the increase in the viscosity of the polymerization liquid also acts, so there is no need to consider special measures to increase the heat transfer area. The temperature difference between the heating medium temperature and the polymerization temperature is often sufficient even if it is relatively small.
In addition, the polymerization temperature as used in the field of this invention refers to the temperature of the stirring fluidization part of a polymerization liquid which is not influenced by the polymerization tank inner wall surface temperature.

(II) Condition of temperature of heating medium The temperature of the heating medium is set to a temperature region in which the weight reduction amount is calculated by the following method and the weight reduction amount is 5 wt% or less.
The temperature of a heating medium here means the temperature of the supply inlet part to apparatuses, such as a polymerization tank.
As a sample used in the method for measuring the weight loss, an aliphatic polyester synthesized using the same composition as the raw material of the aliphatic polyester to be produced is used.

The amount of weight loss under heat retention is almost uniquely determined by the raw material composition used, and is a polymer whose degree of polymerization has progressed to such an extent that almost no volatile raw material monomer remains. Usually, the raw material composition used is the same. If so, it is almost constant regardless of the molecular weight and polymerization conditions.
Method for measuring weight loss:
About 2 to 20 mg of the synthesized aliphatic polyester is heated in TG / DTA 220U (SII Nanotechnology Co., Ltd.) at a rate of 20 ° C./min in a nitrogen atmosphere.

  The measurement temperature has a lower limit of usually 150 ° C. or higher and an upper limit of 320 ° C. or lower, preferably a lower limit of 170 ° C. or higher and an upper limit of 300 ° C. or lower. Measure the weight loss. Next, the temperature conditions at the time of thermal residence are changed, several measurements are performed in the same manner, the weight loss at each temperature is plotted, and the temperature at which the weight loss is 5 wt% or less is calculated.

The temperature at which the weight loss amount is 5 wt% is usually an upper limit of 320 ° C. or lower and a lower limit of 150 ° C. or higher, more preferably an upper limit of 300 ° C. or lower and a lower limit of 160 ° C. or higher.
The temperature of the heating medium can be arbitrarily set at a temperature at which a predetermined polymerization temperature can be maintained as long as the upper limit temperature is calculated and determined from the measurement result using the above TG / DTA and is equal to or lower than the upper limit temperature. In other words, the transmission surface for establishing the heat balance and the necessary heat medium temperature are evaluated and adjusted, and the heat medium temperature at this time can be set if it is not more than the upper limit temperature.

The polymerization reaction is carried out at the temperature of the heating medium set by the above measuring method.
Moreover, the temperature range of the heating medium obtained by the above-described measuring method can also be used when setting the temperature of the heating medium in the esterification reaction and / or transesterification reaction tank.
(2) Esterification reaction and / or transesterification reaction By performing an esterification reaction and / or transesterification reaction with an aliphatic and / or alicyclic diol component, an aliphatic and / or alicyclic dicarboxylic acid component, Short chain or ester compounds can be obtained.

For the esterification reaction and / or transesterification reaction, known methods can be used and are not particularly limited.
The molar ratio of the diol component to the dicarboxylic acid component for obtaining the aliphatic polyester has a preferable range depending on the purpose and the kind of raw material, but the amount of the diol component relative to 1 mol of the dicarboxylic acid component is usually 0 at the lower limit. 0.8 mol or more, preferably 0.9 mol or more, and the upper limit is usually 1.5 mol or less, preferably 1.3 mol or less, particularly preferably 1.2 mol or less. If it deviates from the above range, the polymerization time will be long and the productivity will be lowered, or it will be difficult to achieve a high molecular weight, and it tends to be practically impossible to apply to films and molded products.

The upper limit of the reaction temperature is usually 250 ° C. or lower, the lower limit is 150 ° C. or higher, preferably the upper limit is 240 ° C. or lower, and the lower limit is 200 ° C. or higher.
The reaction atmosphere is usually an inert gas atmosphere such as nitrogen or argon. The reaction pressure is usually normal pressure to 10 kPa, but normal pressure is preferred.
The upper limit of the reaction time is usually 4 hours or less and the lower limit is 0.2 hours or more, preferably the upper limit is usually 3 hours or less and the lower limit is 0.5 hours or more.

The reaction may be performed in one stage or may be performed in a plurality of stages.
The esterification reaction rate is not particularly limited, but the upper limit is usually 98% or less and the lower limit is 80% or more, preferably the upper limit is 96% or less and the lower limit is 85% or more.
The raw material charge is not particularly limited as long as it does not interfere with the reaction, but it is weighed with a balance or a measuring instrument, or supplied while being controlled to a predetermined molar ratio and charge amount using a metering pump or metering feeder. To do.
(3) Polymerization reaction In the polymerization reaction after the esterification reaction and / or the transesterification reaction, the aliphatic diol, by-product water, THF, and the like are distilled out of the polymerization system.

  The polymerization temperature usually has an upper limit of 250 ° C. or lower and a lower limit of 150 ° C. or higher, more preferably an upper limit of 240 ° C. or lower and a lower limit of 200 ° C. or higher. If this temperature is too high, the polymerization time tends to be long or high molecular weight polymers cannot be obtained, and if it is too low, the polymerization time tends to be long or high molecular weight polymers cannot be obtained. There is.

Further, the polymerization reaction may be performed in one stage or may be performed in a plurality of stages.
The polymerization reaction is preferably performed in the presence of a polymerization catalyst. The addition timing of the polymerization catalyst is not particularly limited, and it may be added when the raw materials are charged, or may be added at the start of pressure reduction.
As the polymerization catalyst, in general, a compound containing a group 1 to group 14 metal element excluding hydrogen and carbon in the periodic table can be used. Specifically, at least one metal selected from the group consisting of titanium, zirconium, tin, antimony, cerium, germanium, zinc, cobalt, manganese, iron, aluminum, magnesium, calcium, strontium, sodium, and potassium. And compounds containing an organic group such as carboxylate, alkoxy salt, organic sulfonate, or β-diketonate salt, and inorganic compounds such as metal oxides and halides described above, and mixtures thereof.

  Among these, metal compounds containing titanium, zirconium, germanium, zinc, aluminum, magnesium and calcium, and mixtures thereof are preferable, and among these, titanium compounds and germanium compounds are particularly preferable. In addition, the catalyst is preferably a compound that is liquid at the time of polymerization or that dissolves in an ester low polymer or polyester because the polymerization rate increases when it is melted or dissolved at the time of polymerization.

  The amount of catalyst added in the case of using a metal compound as the polymerization catalyst, the lower limit is usually 5 ppm or more, preferably 10 ppm or more, and the upper limit is usually 30000 ppm or less, preferably 1000 ppm or less, as the amount of metal relative to the produced polyester. More preferably, it is 500 ppm or less, Most preferably, it is 250 ppm or less. If the amount of catalyst used is too large, it is not only economically disadvantageous, but the thermal stability of the aliphatic polyester is low, whereas if it is too low, the polymerization activity is low, the polymerization time is prolonged, Alternatively, the predetermined molecular weight may not be reached.

In addition, a urethane bond, an amide bond, a carbonate bond, an ether bond, or the like can be introduced into the aliphatic polyester as long as the biodegradability is not affected.
Further, during the production process of the aliphatic polyester, or the produced aliphatic polyester, various additives such as a heat stabilizer, an antioxidant, a crystal nucleating agent, a flame retardant, as long as the characteristics are not impaired. You may add an antistatic agent, a mold release agent, a ultraviolet absorber, etc.

The lower limit of the reaction time is usually 1 hour or longer, and the upper limit is usually 10 hours or shorter, preferably 5 hours or shorter.
The lower limit of the pressure is usually 0.01 × 10 ³ Pa or more, preferably 0.03 × 10 ³ Pa or more, and the upper limit is usually a normal pressure or less, preferably 40 kPa or less.
In the present invention, a known vertical or horizontal stirred tank reactor can be used as a reactor for producing the aliphatic polyester. Specifically, using the same or different reactors, the melt polymerization is carried out in two stages of esterification and / or transesterification and reduced pressure polymerization, and the reduced pressure polymerization reactor includes a vacuum pump and a reactor. And a method using a stirred tank reactor equipped with an exhaust pipe for decompression connecting the two. In addition, a method is generally employed in which a condenser is connected between the vacuum pipe connecting the vacuum pump and the reactor, and the volatile components and unreacted monomers generated during the polymerization reaction are recovered by the condenser. . The polymerization form may be either a batch type or a continuous type.

<Physical properties of aliphatic polyester>
The reduced viscosity (ηsp / C) of the aliphatic polyester produced by the above production method usually has an upper limit of 2.8 or less and a lower limit of 1.4 or more, preferably an upper limit of 2.6 or less and a lower limit of 1.6 or more. If the reduced viscosity is too high, the molecular weight becomes non-uniform and pelletization after polymerization tends to be unstable and the amount of cut errors tends to increase, and if it is too low, cuts are insufficient and sufficient strength cannot be obtained, which is practical. It is not desirable because it is not intended.

In addition, the yellow coloration degree Yellow Index (hereinafter referred to as YI) of the pellet usually has an upper limit of 20 or less, and preferably an upper limit of 5 or less. If the value of YI is too high, coloring tends to be severe and tends to be impractical.
In addition, the number of foreign matters (months / 500 g) of the aliphatic polyester cooled and pelletized after being discharged into a strand after the polymerization is usually 10 or less, and preferably 5 or less. When the number of foreign matters is large, it tends to cause a defective appearance of the molded product.

<Aliphatic polyester composition>
You may mix | blend aromatic-aliphatic copolymer polyester, aliphatic oxycarboxylic acid, etc. with the aliphatic polyester manufactured by the manufacturing method of this invention. In addition to carbodiimide compounds, fillers, and plasticizers used as necessary, other biodegradable resins, such as polycaprolactone, polyamide, polyvinyl alcohol, cellulose ester, and the like, as long as the effects of the present invention are not impaired, starch Cellulose, paper, wood powder, chitin / chitosan, animal / plant substance fine powder such as coconut shell powder, walnut shell powder, or a mixture thereof can be blended. Furthermore, additives such as heat stabilizers, plasticizers, lubricants, antiblocking agents, nucleating agents, inorganic fillers, colorants, pigments, ultraviolet absorbers, light stabilizers, etc., are used for the purpose of adjusting the physical properties and processability of the molded product. Further, a modifier, a crosslinking agent, etc. may be included.

  The method for producing the aliphatic polyester composition of the present invention is not particularly limited, but is a method in which raw material chips of the blended aliphatic polyester are melt-mixed in the same extruder, and a method in which each is melted and mixed in separate extruders. And mixing by kneading using a normal kneader such as a single screw extruder, twin screw extruder, Banbury mixer, roll mixer, Brabender plastograph, kneader blender, and the like. In addition, it is possible to obtain a molded body at the same time as preparing a composition by directly supplying each raw material chip to a molding machine.

<Use of aliphatic polyester composition>
Since the aliphatic polyester composition of the present invention has practical properties such as thermal stability, tensile strength, and tensile elongation, it can be formed into a film or laminate by a general-purpose plastic molding method such as an injection molding method, a hollow molding method, and an extrusion molding method. It can be used for molded products such as films, sheets, plates, stretched sheets, monofilaments, multifilaments, non-woven fabrics, flat yarns, staples, crimped fibers, striped tapes, split yarns, composite fibers, blow bottles, foams and the like.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist.
<Calculation of upper limit temperature of heating medium>
100.1 g of succinic acid and 88.7 g of 1-4 butanediol as raw materials, 0.2 g of malic acid, 0.15 g of talc, and a catalyst solution prepared beforehand in a 90% lactic acid aqueous solution so that the germanium dioxide concentration becomes 1 wt% 5.4 g was charged into a 1 L glass polymerization can and placed in an oil bath controlled at 150 ° C. Thereafter, the temperature of the oil bath was raised to 220 ° C. over 1 hour under normal pressure and nitrogen atmosphere, and after reaching 220 ° C., the reaction was further performed for 2 hours. Next, when 2 hours had passed, the pressure reduction was started, the pressure was gradually reduced so that the pressure reached 133 Pa 90 minutes after the start of the pressure reduction, and then the pressure was controlled in the range of 67 Pa to 133 Pa. Also, the temperature of the oil bath starts to rise simultaneously with the start of decompression, and when the temperature reaches 235 ° C. over 60 minutes, the temperature of the oil bath is controlled to 235 ° C., and the produced by-products are distilled out of the system. The reaction was allowed to proceed. The polymerization was terminated after 4 hours had elapsed from the start of decompression, and the pressure was restored with nitrogen and terminated, and the polyester was cooled and pelletized while extracting the aliphatic polyester in a strand form from a glass polymerization can. The aliphatic polyester thus obtained was melted and retained for 2 hours in a nitrogen atmosphere, and the weight loss with respect to a certain heat retention temperature was measured. The results are shown in Table 1.

測定Ｎｏ．１〜３の加熱滞留温度と重量減少の測定結果より、重量減少５ｗｔ％となる加熱滞留温度、つまり加熱媒体の上限の温度を２６８℃と算出した。
＜還元粘度の測定方法＞
フェノールとテトラクロロエタン（重量比１／１）の混合溶媒にポリマーを０．５ｇ／ｄｌの濃度で溶解させ、３０℃でウベローデ粘度管を用いて測定した。

Measurement No. From the measurement results of the heat residence temperature of 1 to 3 and the weight reduction, the heat residence temperature at which the weight reduction is 5 wt%, that is, the upper limit temperature of the heating medium was calculated as 268 ° C.
<Measurement method of reduced viscosity>
The polymer was dissolved in a mixed solvent of phenol and tetrachloroethane (weight ratio 1/1) at a concentration of 0.5 g / dl, and measured at 30 ° C. using an Ubbelohde viscosity tube.

<Measurement of YI>
Using a colorimetric color difference meter (ZE 2000, manufactured by Nippon Denshoku Industries Co., Ltd.), measurement was performed on the pellet-shaped polymer.
<Measurement of the number of foreign objects>
500 g of polymer was collected, and the number of foreign matters that could be visually confirmed was counted.

Example 1
As raw materials, 133.5 kg / H of succinic acid, 118.3 kg / H of 1-4 butanediol, 0.3 kg / H of malic acid, and 0.2 kg / H of talc are supplied to the raw material adjustment tank. Then, while controlling the atmospheric pressure, 140 ° C. and the residence time to 1 hour under nitrogen, it is continuously supplied with a separately prepared catalyst to a 1 m ³ esterification reactor equipped with a vertical stirrer. The reaction was started while removing through the rectification column. The catalyst was supplied to a 90% aqueous lactic acid solution adjusted to a germanium dioxide concentration of 1 wt% at a flow rate of 7.2 kg / H.

The operating conditions of the esterification reaction tank were normal pressure under nitrogen, and the temperature of the heating medium (product name: Therm-s 900) was controlled to be 250 ° C. The residence time was controlled to be 1 hour, and the reaction temperature during esterification at this time was 210 ° C.
The reaction liquid withdrawn from the bottom of the reaction tank is continuously supplied to the first polymerization tank with a vertical stirrer, and the residence time is controlled to 1.5 hours while removing the distillate out of the system. did. The temperature of the heating medium at this time was adjusted to 240 ° C. in order to control the polymerization temperature to 215 ° C.

  Furthermore, the polymerization liquid extracted from the bottom of the first polymerization tank is supplied to the second polymerization tank via a preheater installed in the middle of the transfer pipe from the first polymerization tank to the second polymerization tank, The residence time in the polymerization tank was controlled to be 1.5 hours. At that time, the temperature of the polymerization liquid at the outlet of the preheater was 225 ° C., and the temperature of the heating medium passed through the preheater and the second polymerization tank was adjusted to 250 ° C. The polymerization temperature in the second polymerization tank was 230 ° C.

Subsequently, the residence time was controlled to be 1.5 hours in the final horizontal biaxial third polymerization tank. The temperature of the heating medium at this time was adjusted to 235 ° C. The polymerization temperature was 235 ° C. at the outlet of the polymerization tank. In addition, the pressure of each polymerization tank was made into the 1st polymerization tank 4kpa, the 2nd polymerization tank 133Pa, and the 3rd polymerization tank 67Pa.
After the polymerization was completed, the polymer was cooled while being discharged in a strand shape to obtain a pellet-shaped polymer.

The polymerization temperature and the temperature of the heating medium are shown in FIG.
The obtained aliphatic polyester had a viscosity of 2.46 ηsp / C, a YI of 2.8, a foreign matter number of 1 piece / 500 g of pellets, a high molecular weight, and good quality such as color tone foreign matter.
Example 2
The preheater installed in the middle of the transfer pipe from the first polymerization tank to the second polymerization tank is bypassed, and instead the coil provided inside the second polymerization tank is used together to control the polymerization temperature, In the same manner as in Example 1, an aliphatic polyester was produced. At this time, in order to control the polymerization temperature of the second polymerization tank to 230 ° C., the temperature of the heating medium (product name: Therm-s 900) circulated through the jacket and the internal coil was adjusted to 250 ° C. After the polymerization was completed, the polymer was cooled while being discharged in a strand shape to obtain a pellet-shaped polymer. The polymerization temperature and the temperature of the heating medium are shown in FIG.

The obtained aliphatic polyester had a viscosity of 2.46 ηsp / C, YI of 3.1, the number of foreign matters was 1 piece / 500 g of pellets, and was good as in Example 1.
Example 3
The preheater installed in the middle of the transfer pipe from the first polymerization tank to the second polymerization tank is bypassed. Instead, a part of the polymerization solution in the second polymerization tank is taken out and a heat exchanger installed outside the second polymerization tank. The aliphatic polyester was produced in the same manner as in Example 1 except that the polyester was circulated via the. At this time, in order to control the polymerization temperature of the second polymerization tank to 230 ° C., the temperature of the heating medium (product name: Therm-s 900) circulated through the jacket and the external heat exchanger is 250 ° C.
Adjusted. The polymer temperature at the external heat exchange outlet was 235 ° C. After the polymerization was completed, the polymer was cooled while being discharged in a strand shape to obtain a pellet-shaped polymer. The polymerization temperature and the temperature of the heating medium are shown in FIG.

The obtained aliphatic polyester had a viscosity of 2.43 ηsp / C, a YI of 3.5, a foreign matter number of 2/500 g of pellets, and was as good as in Example 1.
Comparative Example An aliphatic polyester was produced in the same manner as in Example 1 except that the preheater installed in the middle of the transfer pipe from the first polymerization tank to the second polymerization tank was bypassed. In order to control the polymerization temperature of the second polymerization tank to 230 ° C, the temperature of the heating medium circulated through the jacket of the second polymerization tank was adjusted to 270 ° C. After the polymerization was completed, the polymer was cooled while being discharged in a strand shape to obtain a pellet-shaped polymer. The polymerization temperature and the temperature of the heating medium are shown in FIG.

The obtained aliphatic polyester had a viscosity of 2.29 ηsp / C, a YI of 6.2, the number of foreign matters was 8 pieces / 500 g of pellets, the molecular weight was slightly reduced, and the quality such as color foreign matter was also lowered. .
The results of the above examples and comparative examples are shown in Table 2.

It is a schematic diagram which shows an example of the embodiment of this invention.

Claims (2)

  In a method for producing an aliphatic polyester by subjecting an aliphatic and / or alicyclic diol component and an aliphatic and / or alicyclic dicarboxylic acid component to an esterification reaction and / or a transesterification reaction, followed by a polymerization reaction The temperature of the heating medium for controlling the polymerization temperature in the polymerization reaction is set to a temperature range in which the weight reduction amount when the aliphatic polyester is retained by heat of fusion for 2 hours in a nitrogen atmosphere is 5 wt% or less. A process for producing an aliphatic polyester characterized by The temperature of the heating medium for controlling the reaction temperature in the esterification reaction and / or transesterification reaction is 5 wt% or less when the aliphatic polyester is melted and retained for 2 hours in a nitrogen atmosphere. It sets to a temperature range, The manufacturing method of the aliphatic polyester of Claim 1 characterized by the above-mentioned.

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