JP3407767B2 - Method for producing transparent lactic acid-based copolyester and packaging material - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention has excellent transparency and biodegradability and can be molded by various methods such as blow molding, extrusion molding, injection molding, inflation molding, lamination molding, press molding, and extrusion foam molding. The present invention relates to a processable method for producing a transparent lactic acid-based copolyester, and a packaging material comprising the same.

The transparent lactic acid-based copolyester produced by the production method of the present invention is a molding resin, a sheet / film material, a coating resin, an ink resin, an adhesive resin, a paper lamination, or a foamed resin. It is useful as a material and the like, and is particularly useful as a packaging material because of its excellent transparency.

Examples of packaging materials include trays, cups, plates, and blister sheets as sheets, and wrap films, food packaging and other general packaging as films.
It is useful for bags such as garbage bags, shopping bags, standard bags, and heavy bags.

[0004]

2. Description of the Related Art In recent years, lactic acid-based polymers having excellent biodegradability have been actively developed due to environmental problems. Polylactic acid has excellent biodegradability and excellent transparency, but has a drawback of poor flexibility. In order to improve this, for example, in Japanese Patent Laid-Open No. 63145656, lactones are preliminarily polymerized, and polylactic acid is softened by copolymerization with a homopolymer thereof. There is a problem in that the melting point and the glass transition temperature are low and the material becomes opaque.

[0005] US Pat. No. 5,202,413 discloses that polyadipate having a number average molecular weight of 3,400 or polycaprolactone having a number average molecular weight of 2,000 is copolymerized with lactide to soften the polylactide. However, the total content of aliphatic polyester is 15 to 3
When the amount is 0 parts by weight or more, there is a problem that the transparency of the lactic acid-based copolymer is lowered, and conversely, when the polyester content is lowered to give transparency, the flexibility of the copolymer is lowered and the film or sheet is Also, it is not suitable for molding materials that require impact strength.

Further, an aliphatic polyester synthesized by combining a linear diol such as ethylene glycol or 1,4-butanediol with a linear dicarboxylic acid such as succinic acid or adipic acid is copolymerized with lactide. The lactic acid-based copolyester obtained is an aliphatic polyester 15
It becomes opaque when used in an amount of 50 parts by weight or more.

This is because the methylene chain of the polymer main chain of these linear aliphatic polyesters is easily crystallized, and even when copolymerized with lactide, the methylene chain of the polyester block in the copolymer is easily crystallized. Is considered to be.

Further, when a polyester having a weight average molecular weight of 30,000 or less is copolymerized with lactide using 30 parts by weight or more of the whole, the lactic acid-based copolyester produced has a low weight average molecular weight of 30,000 to 50,000, which is sufficient. There was a problem that a polymer having a high strength could not be obtained and the moldability was poor. It is considered that this is because polyester having a low molecular weight has a large number of terminal hydroxyl groups per unit weight, and thus chain transfer easily occurs with the polymerization initiator or the polylactic acid polymerization active terminal.

[0009]

Therefore, an object of the present invention is to provide a method for producing a lactic acid-based copolyester having excellent biodegradability and sufficient transparency and moldability. To do.

[0010]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that the total number of carbon atoms of methylene or methine in the main chains of diol residues and dicarboxylic acid residues is 4 or more. And an aliphatic polyester (A1) having a branched chain consisting of an alkyl group having 1 to 10 carbon atoms, which may have a double bond and / or an ether bond oxygen atom, and a lactide (B). Manufactured by copolymerizing in the presence of a ring-opening polymerization catalyst,

The total amount of the branched diol residue and / or dicarboxylic acid residue derived from the aliphatic polyester is
A lactic acid-based copolyester having 15 to 100 mol% of a diol residue and / or a dicarboxylic acid residue derived from an aliphatic polyester has excellent moldability, biodegradability and transparency, and is a versatile packaging material. Therefore, the present invention has been completed and the present invention has been completed.

[0012]

[Structure] That is, in the present invention, the total number of methylene or methine carbon atoms in the main chain of the diol residue and the dicarboxylic acid residue is 4 or more, and the compound has an oxygen atom having a double bond and / or an ether bond. Good, aliphatic polyester (A1) having a branched chain consisting of an alkyl group having 1 to 10 carbon atoms
And a lactide (B) are copolymerized in the presence of a ring-opening polymerization catalyst, which is a method for producing a transparent lactic acid-based copolymerized polyester.

More specifically, the present invention has a branched chain consisting of an alkyl group having 1 to 10 carbon atoms, which may have a double bond and / or an ether bond oxygen atom in the aliphatic polyester (A1). The total amount of diol residues and / or dicarboxylic acid residues is 15 of all diol residues and / or dicarboxylic acid residues in the aliphatic polyester (A1).
The method for producing a transparent lactic acid-based copolyester is characterized in that the content is -100 mol%.

More specifically, the aliphatic polyester (A
1) and the lactide (B) in a weight ratio of 80:20 to 2:98, which is a method for producing a transparent lactic acid-based copolyester, which is an aliphatic component (A1) constituting component. The method for producing a transparent lactic acid-based copolyester, wherein the main chain of the diol is an alkyl or alkene having 2 to 12 carbon atoms.

In these production methods, the main chain of the aliphatic dicarboxylic acid which is a constituent of the aliphatic polyester (A1) is an alkyl or alkene having 2 to 18 carbon atoms,
Further, these aliphatic polyesters (A1) also include those which are high molecular weight aliphatic polyesters with acid anhydrides or isocyanates.

Furthermore, in the production method of the present invention, the aliphatic polyester (A1) and the lactide (B) are used in combination with the linear aliphatic polyester (A2), and the polyester is co-existed in the presence of a ring-opening polymerization catalyst. It includes a method for producing a transparent lactic acid-based copolyester which is characterized by polymerizing.

More specifically, the present invention is characterized in that the main chain of the aliphatic diol which is a constituent of the aliphatic polyesters (A1) and (A2) is an alkyl or alkene having 2 to 12 carbon atoms. And a transparent lactic acid-based copolyester having a main chain of an aliphatic dicarboxylic acid which is a constituent component of the aliphatic polyesters (A1) and (A2) is an alkyl or alkene having 2 to 18 carbon atoms. The manufacturing method is included.

[0018]

The lactide and polyester used in the production method of the present invention will be described below in order. The lactide used in the present invention is a compound in which two lactic acid molecules are cyclic dimerized by dehydration condensation and is a monomer having a stereoisomer.
That is, lactide includes L-lactide composed of 2 molecules of L-lactic acid, D-lactide composed of 2 molecules of D-lactic acid, and meso-lactide composed of D-lactic acid and L-lactic acid.

The copolymer containing only L-lactide or D-lactide crystallizes and has a high melting point. In the lactic acid-based copolyester of the present invention, preferable resin properties can be realized by combining three types of lactide in various proportions depending on the application.

The aliphatic polyester (A
1) is a carbon in which the total number of methylene or methine carbon atoms in the main chain of the diol residue and the dicarboxylic acid residue is 4 or more, and which may have a double bond and / or ether bond oxygen atom. It has a branched chain composed of an alkyl group of 1 to 10.

For example, propylene glycol, 1,3-
A diol having a branched structure such as butanediol, 1,2-butanediol, 1,4-pentanediol, and 2,4-pentanediol, and a linear dicarboxylic acid such as succinic acid, adipic acid, sebacic acid, and dodecanedioic acid. Polyester consisting of acid,

Or a linear diol such as ethylene glycol, 1,4-butanediol or 1,6-hexanediol and methylsuccinic acid, 2-methyladipic acid, 1-
Polyester composed of dicarboxylic acid having a branched structure such as methylglutaric acid, or branched such as propylene glycol, 1,3-butanediol, 1,2-butanediol, 1,4-pentanediol, 2,4-pentanediol A polyester or the like composed of a diol having a structure and a dicarboxylic acid having a branched structure such as methylsuccinic acid, 2-methyladipic acid, and methylglutaric acid.

The lactic acid-based copolyester obtained by the present invention is a resin having good transparency, and a copolymer having a glass transition temperature of 45 ° C. or higher and a melting point of 140 ° C. or higher can be synthesized. In order to impart high heat resistance, the composition ratio of the aliphatic polyester (A) and the lactide (B) is preferably (A) / (B) in a weight ratio of 20/80 to 98/2, and further, It is preferably 50/50 to 98/2. Furthermore, in the synthesis of a copolymer having a glass transition temperature of room temperature or higher, the composition ratio of lactide and aliphatic polyester used depends on the constituent elements of the aliphatic polyester.

That is, a polyester having a high ester group content per unit weight, for example, a dicarboxylic acid having a methylene chain of 4 or less such as succinic acid and adipic acid, and ethylene glycol,
The polyester (A2) obtained by combining diols having a methylene chain of 4 or less, such as propylene glycol and 1,4-butanediol, comprises a diol or dicarboxylic acid having a methylene chain of 5 or more in the glass transition temperature of the lactic acid-based copolyester. Lower than polymer copolymerized with polyester.

Therefore, when the polyester (A2) is used, it is preferable to control the charged amount to 30 parts by weight or less of the whole. On the other hand, the number of carbon atoms in the main chain is 7 in the methylene chain.
In the case of the above-mentioned dicarboxylic acid or an aliphatic polyester synthesized using a diol having 5 or more carbon atoms in the main chain, the charge amount at the time of copolymerization is kept to 50 parts by weight or less of the whole, and thus 45 ° C. A lactic acid-based copolyester having the above glass transition temperature can be obtained.

The diol used when synthesizing the aliphatic polyester used in the present invention is propylene glycol, 1,3-butanediol, 2,4-butanediol, neopentyl glycol, 3,3-diethyl-1,
3-propanediol, 3,3-dibutyl-1,3-propanediol, 2-allyl-1,3-propanediol, 1,2-butanediol, 1,2-pentanediol,

1,3-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,4-pentanediol, 1,2-hexanediol, 1,3-
Hexanediol, 1,4-hexanediol, 1,5
-Hexanediol, 1-butene-3,4-diol,
4-hydroxymethyl-1-penten-5-ol, butoxyethylene glycol and the like can be mentioned.

When these diols are used, the dicarboxylic acid is a linear dicarboxylic acid having no branched structure, for example, succinic acid, glutaric acid, adipic acid, pimelic acid,
Suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, maleic acid, fumaric acid,
A dicarboxylic acid such as citraconic acid can be used.

In general, a polyester having no branched chain synthesized from a linear diol and a linear dicarboxylic acid is soluble only in a halogen-based solvent or an amide-based solvent, whereas it is synthesized from these diols. The polyester having a branched chain is soluble in tetrahydrofuran, acetone, toluene, benzene, ethylbenzene, xylene, dioxane, chloroform, dichloromethane, chlorobenzene, etc., and widens the solvent selection range in the copolymerization reaction, and the reaction yield Is preferable in terms of improving

As the branched dicarboxylic acid of the aliphatic polyester, for example, methylsuccinic acid, dimethylsuccinic acid, ethylsuccinic acid, 2-methylglutaric acid, 2-ethylglutaric acid, 3-methylglutaric acid, 3-ethylglutaric acid, 2-Methyl adipic acid, 2-ethyl adipic acid, 3-methyl adipic acid, 3-ethyl adipic acid, etc. can be used.

In this case, in addition to the above-mentioned branched diols, linear diols having no branched chain, for example, ethylene glycol, 1,3-propanediol, 1,4-
Butanediol, 1,5-pentanediol, 1,6-
Hexanediol, 1,7-heptanediol, 1,8
-Octanediol, 1,9-nonanediol, 1,1
A diol such as 0-decanediol can be used.

By using these linear diols in combination with the above-mentioned branched diols,
It can be polycondensed with an inexpensive linear dicarboxylic acid to give a transparent polyester, and further a transparent lactic acid-based copolyester can be synthesized. In this case, in order to maintain transparency, a transparent polyester can be obtained by using the linear diol in an amount not exceeding 85 mol% based on the total diol.

The lactic acid-based copolymer is preferably one having a high molecular weight because it can be molded and processed in a wide temperature range. Specifically, a lactic acid-based copolymer having a weight average molecular weight of 70,000 to 400,000 is preferable. preferable. When the lactic acid-based copolyester having this molecular weight range was formed into a sheet and measured by RSAII manufactured by Rheometrics Co., Ltd., the storage elastic modulus was 500 to 50,000 kg / cm ² .

Further, when the lactide is copolymerized, lactones such as ε-caprolactone and γ-butyrolactone vary with the total polyester component used,
It is possible to further soften the lactic acid-based copolyester by using the lactic acid-based copolyester in a range that does not impair the transparency, usually 0.1 to 30 parts by weight.

In order to synthesize such a high-molecular-weight lactic acid-based copolyester, it is preferable that the aliphatic polyester used as a raw material has a sufficiently high molecular weight. In ordinary polyester production, a deglycolization reaction by heating at high temperature for a long time is used for increasing the molecular weight of polyester, but coloring of the polyester due to oxidation becomes a problem.

In the present invention, an organic metal catalyst such as titanium, tin, zinc or zirconium is used in an amount of 50 to 1 with respect to polyester.
Transesterification is performed using 000 ppm, and antioxidant such as phosphite ester compound is added to 50 to 1000 ppm.
Coloring can be reduced by adding.

However, it is usually difficult to obtain an aliphatic polyester having a molecular weight of 100,000 or more without coloring at all. Therefore, by suppressing the reaction temperature to 230 ° C. or lower and synthesizing a polyester having a molecular weight of 20,000 to 30,000, and reacting this with polyfunctional isocyanate, carboxylic acid anhydride, etc., the molecular weight of the polyester can be increased to 100,000 or more. The molecular weight is preferable in that the coloring can be suppressed.

The reaction between the aliphatic polyester and the carboxylic acid anhydride or isocyanate is carried out by mixing the reaction product immediately after the polyester polymerization reaction between the diol and dicarboxylic acid is completed with the carboxylic acid anhydride or isocyanate and melting the mixture for a short time. A method of stirring and reacting in the state or a method of adding again to the polyester obtained by polymerization and melt-mixing may be used.

Particularly preferred is a method in which both the aliphatic polyester, the carboxylic acid anhydride, and the isocyanate are dissolved in a cosolvent, and the mixture is heated and reacted to cause reprecipitation or degassing. As a result, the carboxylic acid anhydride and the isocyanate can be very uniformly dispersed in the aliphatic polyester.

The temperature at which the aliphatic polyester is mixed with the carboxylic acid anhydride or isocyanate and allowed to react is usually 70 ° C to 240 ° C, preferably 100 ° C to 190 ° C. Also, in the reaction, N, N-dimethylaniline,
It is preferable to use an ester polymerization catalyst such as tin octoate, dibutyltin dilaurate or isopropyl titanate, or a urethane catalyst.

The above-mentioned carboxylic acid anhydride and isocyanate can be used as a mixture, if necessary. Also,
The amount of these used is preferably 0.01% by weight to 5% by weight of the aliphatic polyester, more preferably 0.1% by weight.
~ 1% by weight.

Next, the manufacturing method will be described in order. The diol and the dicarboxylic acid are stirred at a molar ratio of 1.4: 1 under a nitrogen atmosphere while gradually raising the temperature from 130 ° C to 220 ° C at a rate of 5 to 10 ° C per hour to distill off water. At this time, if the temperature rising rate is too high, glycol is likely to be distilled off together with water. After reacting for 8 to 12 hours, 10 to 0.5 torr
Excess glycol is distilled off while gradually increasing the degree of vacuum at r.

After the pressure was reduced for 2 to 3 hours, a transesterification catalyst and an antioxidant were added, and 170 ° C. to 2 at 0.5 torr.
The temperature is raised to 30 ° C. over 6 hours. A viscous liquid polyester is obtained by reacting at 230 ° C. for 1 hour. 1
At 80 ° C. to 210 ° C., add carboxylic anhydride or diisocyanate to this polyester, and add 0.5 torr.
A high molecular weight polyester is obtained by carrying out the reaction under reduced pressure for 3 hours. When oxygen is introduced into the reaction system, it causes coloring and decomposition. Therefore, when releasing the reduced pressure such as adding a catalyst, it is preferable to sufficiently replace with an inert gas such as nitrogen.

In the ring-opening polymerization of lactide, a reaction temperature of 185 ° C. or lower, preferably 180 ° C. or lower is preferable from the viewpoint of preventing coloring and decomposition, and in order to prevent decomposition and coloring of lactide, an inert gas such as nitrogen and argon is used. It is preferable to carry out the reaction under a gas atmosphere. Since the presence of water in the reaction system is not preferable, the aliphatic polyester used must be sufficiently dried.

Next, the method of copolymerization will be described. The aliphatic polyester (A) and the lactide (B) are dissolved in 15 to 30 parts by weight of toluene based on the total weight of these, and a ring-opening polymerization catalyst such as tin octoate is added at 140 to 180 ° C. under a nitrogen atmosphere. 50 to 2000 ppm is added to the total weight of polyester and lactide.

Lactide is soluble in various solvents and can be copolymerized by using solvents such as toluene, benzene, xylene, ethylbenzene, cyclohexanone, methyl ethyl ketone and isopropyl ether. Regarding the polymerization reaction, it is considered that the polymerization-promoting terminal of lactide reacts with polyester and the copolymerization reaction proceeds by the transesterification reaction.

By tracking the polymerization reaction by gel permeation chromatography (GPC), the polyester peak is absorbed by the lactide peak as the reaction proceeds, and the weight average molecular weight of the single peak is 50,000 to 200,000. It is confirmed that the copolymer of By reacting at 160 to 180 ° C. for 3 hours or more, the conversion rate of this polymerization reaction reaches 90 to 99%.

The lactic acid-based copolyester of the present invention can be produced by using an ordinary reaction kettle, but in order to increase the viscosity accompanied by the increase in the molecular weight, the co-polyester used in the ordinary reaction kettle is used. In the polymerization reaction, the stirring efficiency is lowered, which causes coloring due to local heating and a reduction in the reaction rate. Therefore, in the present production method, it is preferable to use a static mixer that is uniformly stirred and has a small shear stress.

The reaction can be carried out only with a static mixer, but it is more preferable to use an ordinary reaction vessel at a low viscosity stage and a static mixer at a high viscosity stage in the latter stage of polymerization.

The lactic acid-based copolyester obtained in the present invention is characterized by having transparency after being melted and allowed to cool at room temperature. That is, even with a lactic acid-based copolyester obtained by a production method other than the production method of the present invention, a transparent product can be obtained when a sheet or film is prepared by rapidly cooling the polymer after melting, but it becomes white over time. And make it opaque. It is considered that this is because the components in the lactic acid-based copolyester gradually crystallize.

In the present invention, a polymer prepared by melting a polymer at a melting point or higher, forming a PET sheet into a film having a thickness of 250 μm using a spacer, and then allowing it to cool at room temperature for 12 hours is measured by JIS-K-7127. And haze is 20%
The following is called transparent. The lactic acid-based copolyester obtained in the present invention has a film thickness of 250 μm and a transmittance of 96 to 75% and a haze of 1 as measured by JIS-K-7127.
A -20% transparent sheet is obtained, which has excellent storage stability and does not easily opacify.

The lactic acid-based copolyester obtained in the present invention has a glass transition temperature of 20 ° C to 60 ° C. In the lactic acid-based copolyester of the present invention, the glass transition temperature of the lactic acid-based copolyester produced varies depending on the polyester component used for the copolymerization. That is, in the case where the total number of carbon atoms in the main chain of the dicarboxylic acid is 12 or more and the diol that constitutes the polyester, even if 30 to 50 parts by weight of the polyester (A3) is used, the glass transition temperature of the lactic acid-based copolyester is It is 40 ° C or higher.

The viscoelasticity of the lactic acid-based copolyester at room temperature becomes softer as the number of carbon atoms in the main chain of the diol and dicarboxylic acid constituting the aliphatic polyester used for the copolymerization increases. The lactic acid-based copolyester having a softening temperature of 30 ° C. or less obtained in the present invention can be cooled to room temperature with a cooling medium at the time of molding to obtain a transparent sheet having a thickness of 250 μm and a haze of 5% or less. When gradually cooled, crystallization of the lactide part partially proceeds and the haze of the sheet is 10 to 10.
It becomes 20% and the transparency is slightly lowered.

The lactic acid-based copolyester obtained in the present invention has a good biodegradability, and even when it is dumped in the sea, it is decomposed by hydrolysis, biodegradation and the like. In seawater, its strength as a resin deteriorates within a few months, and it can be decomposed without maintaining its outer shape. In addition, if compost is used, it will be biodegraded in a shorter period of time before its original shape is retained.

The transparent lactic acid-based copolyester produced by the production method of the present invention is a molding resin, a sheet / film material, a paint resin, an ink resin, an adhesive resin, a paper lamination, or a foamed resin. It is useful as a material, especially as a packaging material. Examples of the packaging material include a tray, a cup, a plate, and a blister as a sheet, a wrap film as a film, a food packaging, other general packaging, a garbage bag, a plastic bag, a general standard bag, a bag such as a heavy bag, and the like. Useful for.

It is also useful as a blow molded product for other purposes, for example, in shampoo bottles, cosmetic bottles, beverage bottles, oil containers and the like, and as sanitary products such as disposable diapers, sanitary products and medical products. As artificial kidneys, sutures, etc., and as agricultural materials, germination sheet, seed string,
It is useful as agricultural mulch film, slow-acting pesticide and fertilizer coating agent, bird-proof net, curing sheet, seedling pot, etc.

As fishing materials, fishing nets, seaweed cultivation nets, fishing lines, ship bottom paints, etc., and injection molded products,
Golf tee, cotton swab core, candy stick, brush,
It is useful for toothbrushes, syringes, dishes, cups, combs, razor handles, tape cassettes, disposable spoons / forks, stationery such as ballpoint pens.

As a lamination product for paper,
Tray, cup, plate, megaphone, etc., as well as binding tape, prepaid card, balloon, pantyhose, hair cap, sponge, cellophane tape, umbrella,
Examples of the material include synthetic feathers, plastic gloves, hair caps, ropes, non-woven fabrics, tubes, foam trays, foam cushioning materials, cushioning materials, packing materials, hot melt adhesives, and cigarette filters.
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[0060]

【Example】

Reference Example 1 (Synthesis of Aliphatic Polyester A-1) In a four-necked flask equipped with a stirrer, a rectifier, and a gas introduction tube, 1 molar equivalent of adipic acid and 1.35 molar equivalents of propylene glycol were added. After charging, the mixture was heated and stirred under a nitrogen stream while increasing the temperature from 150 ° C by 7 ° C per hour. The temperature was raised to 220 ° C. while distilling off the produced water, and when the distilling of water stopped, 70 ppm of titanium tetraisopropoxide was added as an ester exchange catalyst, and the mixture was stirred under reduced pressure to a maximum of 0.5 torr.

230 ° C after the distillation of glycol is stopped
By continuing the reaction for 1 hour, a viscous aliphatic polyester (referred to as A-1) was obtained. The number average molecular weight of this polymer was determined by gel permeation chromatography in terms of polystyrene (hereinafter abbreviated as GPC) to be 19,
And the weight average molecular weight was 25,000.

Reference Example 2 (Aliphatic Polyester A-2)
Synthesis) A 4-necked flask equipped with a stirrer, a rectifier, and a gas inlet tube was charged with 1 molar equivalent of sebacic acid and 1.35 molar equivalent of propylene glycol, and the temperature was changed from 150 ° C to 1 hour under a nitrogen stream. The mixture was heated and stirred while raising the temperature by 10 ° C. While distilling off the produced water, the temperature was raised to 220 ° C., and after the distilling of water stopped, 60 ppm of tin octoate was added to 0.5 to
The mixture was stirred for 2 hours while gradually reducing the pressure to rr.

By continuing the reaction at 230 ° C. for 1 hour, a viscous liquid aliphatic polyester (referred to as A-2) having a number average molecular weight of 21,000 and a weight average molecular weight of 35,000 by GPC is obtained. It was

Reference Example 3 Aliphatic Polyester A-3
Synthesis) In a reaction kettle equipped with a stirrer, a rectifier, and a gas introduction tube, 1 mol equivalent of sebacic acid and 1.35 mol equivalent of 1,3-butanediol were charged, and the temperature was changed from 150 ° C to 1 hour under a nitrogen stream. 10
The mixture was heated and stirred while the temperature was raised by ° C.

While distilling off the produced water, the temperature was raised to 220.degree. C., and after the distillation of water was stopped, 120 ppm of titanium oxyacetylacetonate was added, and the mixture was stirred at 230.degree. C. for 2 hours while reducing the pressure to 1.5 torr. The reaction was continued for 4 hours at a number average molecular weight of 17,000 and a weight average molecular weight of 2
2,000 viscous transparent liquid aliphatic polyesters (referred to as A-3) were obtained.

Reference Example 4 (Aliphatic Polyester A-4)
Synthesis of) A 4-necked flask equipped with a stirrer, a rectification unit, and a gas inlet tube was charged with 1 molar equivalent of dodecanedioic acid and 1.2 molar equivalents of propylene glycol, and the temperature was changed from 150 ° C to 1 ° C under a nitrogen stream.
The mixture was heated and stirred while the temperature was raised by 10 ° C. for an hour. The temperature was raised to 220 ° C. while distilling off the produced water, and after the distilling of water was stopped, 70 ppm of titanium tetraisopropoxide was added and a deglycolization reaction was carried out for 4 hours while reducing the pressure to 0.6 torr.

After the distillation of glycol is stopped, 23
By continuing the reaction at 0 ° C for 1 hour, the number average molecular weight is 1
A viscous transparent liquid aliphatic polyester (referred to as A-4) having a molecular weight of 3,000 and a weight average molecular weight of 27,000 was obtained.

Reference Example 5 (Aliphatic Polyester A-5)
Synthesis) A 4-necked flask equipped with a stirrer, a rectifier, and a gas introduction tube was charged with 1 molar equivalent of maleic acid and 1.35 molar equivalents of 2,3-butanediol, and the temperature was changed from 150 ° C to 1 ° C under a nitrogen stream. The mixture was heated and stirred while the temperature was raised by 10 ° C. for an hour. After reacting at 220 ° C. for 4 hours while distilling off the produced water, 150 ppm of titanium tetraisopropoxide was added to 0.5 to
The mixture was stirred while reducing the pressure to rr. The number average molecular weight was 18,000 and the weight average molecular weight was 30,000 by continuing the reaction at 230 ° C. for 1 hour after the distillation of glycol stopped.
0 viscous transparent liquid aliphatic polyester (A-5
Called. ) Got.

Reference Example 6 Aliphatic Polyester A-6
Synthesis) In a four-necked flask equipped with a stirrer, a rectifier, and a gas inlet tube, 0.5 mol equivalent of methylsuccinic acid and 0.5 maleic acid were added.
A molar equivalent of 1,3-butanediol (1.35 molar equivalent) was charged, and the mixture was heated and stirred under a nitrogen stream while heating from 150 ° C to 10 ° C for 1 hour.

While distilling off the produced water, the temperature was raised to 220 ° C., and when distilling of water was stopped, tin laurate was added to 350 ° C.
ppm was added and the mixture was stirred while reducing the pressure to a maximum of 0.5 torr. 1 at 230 ° C after the distillation of glycol stopped
By continuing the reaction for a time, a number average molecular weight of 20,000
A viscous transparent liquid aliphatic polyester having a weight average molecular weight of 30,000 (referred to as A-6) was obtained.

Reference Example 7 Aliphatic Polyester A-7
Synthesis of 4) In a four-necked flask equipped with a stirrer, a rectifier, and a gas introduction tube, 1 equivalent of dodecanedioic acid and neopentyl glycol 1.
Charge 35 equivalents and under a nitrogen stream from 150 ° C to 220 ° C
The mixture was heated and stirred while raising the temperature by 10 ° C. for 1 hour. Titanium tetraisopropoxide 1
20 ppm was added and the mixture was stirred for 4 hours while reducing the pressure to a maximum of 0.7 torr. Further, the reaction was continued at 230 ° C. for 1 hour to obtain a viscous transparent liquid aliphatic polyester (referred to as A-7) having a number average molecular weight of 19,000 and a weight average molecular weight of 34,000.

(Reference Example 8) (Synthesis of high molecular weight aliphatic polyester A-8) The aliphatic polyester (A-2) synthesized in Reference Example 2 was placed in a separable flask and pyromellitic dianhydride (PMD) was added.
A) Add 0.5 parts by weight and heat to 210 ° C. 1
The mixture was stirred under reduced pressure at torr. After 3 hours, the viscosity rose sharply. It was confirmed that the obtained polymer was soluble in tetrahydrofuran (THF) and acetone and did not gel. It was confirmed by GPC that this polymer was a high molecular weight aliphatic polyester (referred to as A-8) having a number average molecular weight of 41,000 and a weight average molecular weight of 125,000.

Reference Example 9 (Synthesis of High Molecular Weight Aliphatic Polyester A-9) The aliphatic polyester (A-3) synthesized in Reference Example 3 was placed in a separable flask and used as an acid anhydride by Dainippon Ink Co., Ltd. Company Epicron 4400 (EP4400) 0.3
One part by weight was added, and the mixture was heated to 180 ° C. and stirred for 1 hour.
Next, while heating at 210 ° C., the pressure was reduced to 1 torr and the mixture was stirred. After 4 hours, an increase in viscosity was observed. The polymer obtained is a liquid and has a transparent number average molecular weight of 3,200.
A viscous transparent high molecular weight aliphatic polyester (A-9) having a weight average molecular weight of 97,000 was obtained.

(Reference Example 10) (Synthesis of high molecular weight aliphatic polyester A-10) The aliphatic polyester (A-4) synthesized in Reference Example 4 was placed in a reaction kettle and phthalic anhydride (PhA) 0.3 Part by weight was added, and the mixture was heated to 190 ° C. and stirred for 1 hour. Then 21
The mixture was stirred under reduced pressure of 1 torr while heating at 0 ° C. Two
After a lapse of time, an increase in viscosity was observed, and the obtained polymer was
A viscous and transparent high molecular weight aliphatic polyester (A-10) having a liquid and transparent number average molecular weight of 40,000 and a weight average molecular weight of 87,000 was obtained. This polymer is
It was soluble in organic solvents such as chloroform, acetone and THF.

Reference Example 11 (Synthesis of high molecular weight aliphatic polyester A-11) The aliphatic polyester (A-5) synthesized in Reference Example 5 was placed in a separable flask and maleic anhydride (MAnh) was added.
0.5 part by weight was added, and the mixture was heated to 180 ° C. and stirred for 1 hour. Next, while heating at 210 ° C., the pressure was reduced to 1 torr and the mixture was stirred. A sharp increase in viscosity was observed after 3 hours. The obtained polymer (A-11) was a viscous and transparent resin having a number average molecular weight of 45,000 and a weight average molecular weight of 79,000. This polymer was soluble in organic solvents such as chloroform, acetone and THF.

(Reference Example 12) (Synthesis of high molecular weight aliphatic polyester A-12) The aliphatic polyester (A-6) synthesized in Reference Example 6 was placed in a separable flask and trimellitic anhydride (TMA) was added.
Add 0.4 parts by weight and heat to 210 ° C. for 0.5 to
The mixture was stirred under reduced pressure at rr. After 3 hours, a viscous and transparent high molecular weight aliphatic polyester (A-12) having a number average molecular weight of 37,000 and a weight average molecular weight of 87,000 was obtained. This polymer contains chloroform, acetone,
It was soluble in organic solvents such as THF.

Reference Example 13 (Synthesis of High Molecular Weight Aliphatic Polyester A-13) The aliphatic polyester (A-7) synthesized in Reference Example 7 was placed in a separable flask, and hexamethylene diisocyanate (HMDI) 0. 4 parts by weight was added, and the mixture was heated to 190 ° C. and stirred under reduced pressure to 0.5 torr. After 3 hours, number average molecular weight 37,000, weight average molecular weight 9
7,000 viscous and transparent high molecular weight aliphatic polyester (A-13) was obtained. This polymer was soluble in organic solvents such as chloroform, acetone and THF.

(Example 1) (Synthesis of lactic acid-based copolyester) 30 parts by weight of an aliphatic polyester (referred to as A-14) having a weight average molecular weight of 24,000 synthesized from propylene glycol and succinic acid, and L- 68.5 parts by weight of lactide, 1.5 parts by weight of D-lactide, and 15 parts by weight of toluene based on the total amount of lactide and the aliphatic polyester were placed in a separable flask and melted at 170 ° C. 200 pp of tin octoate after the solution becomes uniform
m was added and the mixture was stirred at 170 ° C. for 3.5 hours.

The lactic acid-based copolyester obtained was G
PC number average molecular weight 40,000, weight average molecular weight 7
It was confirmed to be 5,000 copolymers. The glass transition temperature of this polymer was 3 with a differential calorimeter (DSC).
It was 2 ° C.

(Example 2) (Synthesis of lactic acid type copolyester) High molecular weight aliphatic polyester (A) synthesized in Reference Example 1
-1) 8.5 parts by weight, 91 parts by weight of L-lactide,
0.5 parts by weight of D-lactide and 15 parts by weight of toluene based on the total amount of lactide and the aliphatic polyester were placed in a separable flask and melted at 170 ° C. After the solution became uniform, 200 ppm of tin octoate was added, and the mixture was stirred at 170 ° C for 3.5 hours.

The lactic acid-based copolyester obtained was G
PC number average molecular weight 69,000, weight average molecular weight 9
It was confirmed to be 2,000 copolymers. The glass transition temperature of this polymer is 4 with a differential calorimeter (DSC).
It was 9 ° C.

(Example 3) (Synthesis of lactic acid type copolyester) High molecular weight aliphatic polyester (A) synthesized in Reference Example 1
-1) 15 parts by weight, L-lactide 83.9 parts by weight, D-lactide 1.1 parts by weight, and 15 parts by weight of toluene based on the total amount of lactide and the aliphatic polyester were placed in a separable flask. It was put and melted at 170 ° C. 200 pp of tin octoate after the solution becomes uniform
m was added and the mixture was stirred at 170 ° C. for 3.5 hours.

The lactic acid-based copolyester obtained was G
PC number average molecular weight 39,000, weight average molecular weight 7
It was confirmed to be 4,000 copolymers. The glass transition temperature of this polymer is 4 with a differential calorimeter (DSC).
It was 3 ° C.

(Example 4) (Synthesis of lactic acid-based copolyester) The high molecular weight aliphatic polyester (A) synthesized in Reference Example 1
-1) 30 parts by weight, 69.5 parts by weight of L-lactide, 0.5 part by weight of D-lactide, and 15 parts by weight of toluene based on the total amount of lactide and the aliphatic polyester were placed in a separable flask. It was put and melted at 170 ° C. 200 pp of tin octoate after the solution becomes uniform
m was added and the mixture was stirred at 170 ° C. for 3.5 hours.

The lactic acid-based copolyester obtained was G
PC number average molecular weight 39,000, weight average molecular weight 6
It was confirmed to be 2,000 copolymers. The glass transition temperature of this polymer is 2 with a differential calorimeter (DSC).
It was 0 ° C.

(Example 5) (Synthesis of lactic acid-based copolyester) The high molecular weight aliphatic polyester (A) synthesized in Reference Example 8
-8) 8.5 parts by weight, 90 parts by weight of L-lactide,
1.5 parts by weight of D-lactide and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask and melted at 170 ° C. After the solution became uniform, add 500 ppm of zinc octoate,
The mixture was stirred at 173 ° C for 4 hours. The obtained polymer is GPC
With a number average molecular weight of 77,000, a weight average molecular weight of 120,
It was confirmed to be a copolymer of 000. The glass transition temperature was 57 ° C.

(Example 6) (Synthesis of lactic acid type copolyester) High molecular weight aliphatic polyester (A) synthesized in Reference Example 8
-8) Take 30 parts by weight, 68.9 parts by weight of L-lactide, 1.1 parts by weight of D-lactide, and 15 parts by weight of toluene with respect to the total amount of lactide and polyester in a separable flask, Melted at 170 ° C. After the solution became uniform, 500 ppm of zinc octanoate was added, and the mixture was stirred at 173 ° C. for 4 hours. The polymer obtained is G
PC number average molecular weight 67,000, weight average molecular weight 10
It was confirmed to be 2,000 copolymers. The glass transition temperature was 56 ° C.

(Example 7) (Synthesis of lactic acid-based copolyester) High molecular weight aliphatic polyester (A) synthesized in Reference Example 8
-8) 40 parts by weight, 59.0 parts by weight of L-lactide, 1 part by weight of D-lactide, and 15 parts by weight of toluene based on the total amount of lactide and polyester are placed in a separable flask and heated to 170 ° C. Melted in. After the solution became uniform, add 500 ppm of zinc octoate,
The mixture was stirred at 173 ° C for 4 hours. The obtained polymer is GPC
Number average molecular weight 57,000, weight average molecular weight 82.0
It was confirmed to be a copolymer of 00. The glass transition temperature was 52 ° C.

(Example 8) (Synthesis of lactic acid-based copolyester) High molecular weight aliphatic polyester (A) synthesized in Reference Example 8
-8) 60 parts by weight, 40 parts by weight of L-lactide and 15 parts of toluene based on the total amount of lactide and polyester.
And parts by weight were placed in a separable flask and melted at 170 ° C. After the solution becomes uniform, zinc octanoate 500p
pm was added, and the mixture was stirred at 173 ° C. for 4 hours. The obtained polymer was a copolymer having a number average molecular weight of 41,000 and a weight average molecular weight of 55,000 by GPC, and the glass transition temperature was 44 ° C.

(Example 9) (Synthesis of lactic acid-based copolyester) High molecular weight aliphatic polyester (A) synthesized in Reference Example 9
-9) 30 parts by weight, L-lactide 69 parts by weight, D
1 part by weight of lactide and 15 parts by weight of toluene with respect to the total amount of lactide and polyester were taken in a separable flask and melted at 170 ° C. After the solution became uniform, 500 ppm of zinc octoate was added, and 173
The mixture was stirred at 0 ° C for 4 hours. It was confirmed by GPC that the obtained polymer was a copolymer having a number average molecular weight of 73,000 and a weight average molecular weight of 97,000. Glass transition temperature is 5
It was 2 ° C.

(Example 10) (Synthesis of lactic acid-based copolyester) 30 parts by weight of the high molecular weight aliphatic polyester (A-10) synthesized in Reference Example 10, 69 parts by weight of L-lactide, and D-lactide 1 part by weight and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask and melted at 170 ° C. After the solution became uniform, add 300 ppm of zinc octoate,
The mixture was stirred at 173 ° C for 4 hours. The obtained polymer is GPC
Number average molecular weight 60,000, weight average molecular weight 92.0
It was confirmed to be a copolymer of 00. The glass transition temperature was 53 ° C.

(Example 11) (Synthesis of lactic acid-based copolyester) Aliphatic polyester (A-10) synthesized in Reference Example 10
40 parts by weight, L-lactide 59.2 parts by weight, D-
0.8 parts by weight of lactide and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask and melted at 170 ° C. After the solution became uniform, add 500 ppm of zinc octoate,
The mixture was stirred at 3 ° C for 4 hours. The obtained polymer has a number average molecular weight of 57,000 by GPC and a weight average molecular weight of 84,000.
It was confirmed to be a copolymer of The glass transition temperature was 50 ° C.

(Example 12) (Synthesis of lactic acid-based copolyester) 20 parts by weight of the high molecular weight aliphatic polyester (A-11) synthesized in Reference Example 11, 2 parts by weight of ε-caprolactone, and L-lactide 78 parts by weight and D-lactide 2
Parts by weight and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask equipped with a reflux condenser and melted at 170 ° C.

After the solution became uniform, 150 ppm of titanium tetraisopropoxide was added, and the mixture was stirred at 165 ° C. for 6 hours. The polymer obtained has a number average molecular weight of 6 by GPC.
It was confirmed to be a copolymer having a weight average molecular weight of 2,000 and 100,000. The glass transition temperature was 44 ° C.

(Example 13) (Synthesis of lactic acid type copolyester) 30 parts by weight of the high molecular weight aliphatic polyester (A-12) synthesized in Reference Example 12, 69 parts by weight of L-lactide and D-lactide 1 part by weight and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask equipped with a reflux condenser and melted at 170 ° C.

After the solution became uniform, 400 ppm of tetramethoxystannate was added and stirred at 175 ° C. for 2 hours, and then this polymer was fed to a static mixer at 175 ° C. at 500 mL / hour to obtain the obtained polymer. Pelletized. The obtained polymer was a copolymer having a number average molecular weight of 78,000 by GPC and a weight average molecular weight of 139,000, and the glass transition temperature of the polymer was 48 ° C.

(Example 14) (Synthesis of lactic acid type copolyester) 30 parts by weight of the high molecular weight aliphatic polyester (A-13) synthesized in Reference Example 13, 69 parts by weight of L-lactide and D-lactide 1 part by weight and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask equipped with a reflux condenser and melted at 170 ° C.

After the solution became uniform, 400 ppm of tetramethoxystannate was added, and the mixture was stirred at 175 ° C. for 2 hours, and then this polymer was fed to a static mixer at 175 ° C. at 500 mL / hour to obtain the obtained polymer. Pelletized. The obtained polymer was a copolymer having a number average molecular weight of 56,000 by GPC and a weight average molecular weight of 94,000, and the glass transition temperature of the polymer was 23 ° C.

(Example 15) (Synthesis of lactic acid-based copolyester) A number average molecular weight of 42,000 and a weight average molecular weight of 75, which were synthesized from 0.35 molar equivalent of diethylene glycol, 1 molar equivalent of propylene glycol and 1 molar equivalent of adipic acid.
15 parts by weight of 000 aliphatic polyester (A-15), 83 parts by weight of L-lactide, 2 parts by weight of D-lactide and 15 parts by weight of toluene based on the total amount of lactide and polyester. It was taken in a separable flask and melted at 170 ° C.

After the solution became uniform, 400 ppm of tetramethoxystannate was added, and the mixture was stirred at 175 ° C. for 4 hours. The polymer obtained has a number average molecular weight of 68 by GPC,
000, a weight average molecular weight of 102,000,
The glass transition temperature of the polymer was 40 ° C.

(Example 16) (Synthesis of lactic acid-based copolyester) A number average molecular weight of 32,000 and a weight average molecular weight of 72 were synthesized from ethylene glycol 0.5 molar equivalent, propylene glycol 1 molar equivalent and adipic acid 1 molar equivalent. , 00
15 parts by weight of aliphatic polyester (A-16) of 0, and L
-83 parts by weight of lactide, 2 parts by weight of D-lactide and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask equipped with a reflux condenser and melted at 170 ° C.

After the solution became uniform, 400 ppm of tetramethoxystannate was added, and the mixture was stirred at 175 ° C. for 4 hours. The polymer obtained has a number average molecular weight of 68 by GPC,
000, a copolymer having a weight average molecular weight of 117,000,
The glass transition temperature of the polymer was 43 ° C.

[0103]

Next, this sheet was taken out and allowed to cool at room temperature for 12 hours. Obtained 10 cm x 10 cm, thickness 250
When the haze of the sheet of μm was measured by JIS-K-7127, the haze of this sheet was 3.2%.

(Comparative Example 1) (Synthesis of lactic acid-based copolyester) 15 parts by weight of an aliphatic polyester having a weight average molecular weight of 20,000 synthesized from ethylene glycol and succinic acid,
83.9 parts by weight of L-lactide and 1.
1 part by weight and 15 parts by weight of toluene based on the total amount of lactide and aliphatic polyester were placed in a separable flask and melted at 170 ° C. After the solution became uniform, 200 ppm of tin octoate was added, and the mixture was stirred at 170 ° C for 3.5 hours.

The lactic acid-based copolyester obtained was G
PC number average molecular weight 41,000, weight average molecular weight 6
It was confirmed to be a copolymer of 8,000. The glass transition temperature of this polymer is 4 with a differential calorimeter (DSC).
It was 3 ° C.

(Comparative Example 2) (Synthesis of lactic acid type copolyester) 20 parts by weight of an aliphatic polyester having a weight average molecular weight of 20,000 synthesized from ethylene glycol and succinic acid,
78 parts by weight of L-lactide and 2 parts by weight of D-lactide were placed in a separable flask with 15 parts by weight of toluene based on the total amount of lactide and aliphatic polyester, and 1
Melted at 70 ° C. After the solution became uniform, 200 ppm of tin octoate was added, and the mixture was stirred at 170 ° C for 3.5 hours.

The lactic acid-based copolyester obtained was G
PC number average molecular weight 37,000, weight average molecular weight 6
It was confirmed to be 50,000 copolymers. The glass transition temperature of this polymer was 3 with a differential calorimeter (DSC).
It was 9 ° C.

(Comparative Example 3) (Synthesis of lactic acid type copolyester) 30 parts by weight of an aliphatic polyester having a weight average molecular weight of 20,000 synthesized from ethylene glycol and succinic acid,
77.5 parts by weight of L-lactide and D-lactide 2.
5 parts by weight and 15 parts by weight of toluene based on the total amount of lactide and aliphatic polyester were put in a separable flask and melted at 170 ° C. After the solution became uniform, 200 ppm of tin octoate was added, and the mixture was stirred at 170 ° C for 3.5 hours.

The lactic acid-based copolyester obtained was G
PC number average molecular weight 38,000, weight average molecular weight 6
It was confirmed to be 5,000 copolymers. The glass transition temperature of this polymer was 3 with a differential calorimeter (DSC).
It was 5 ° C.

(Comparative Example 4) (Synthesis of lactic acid-based copolyester) 15 parts by weight of aliphatic polyester having a number average molecular weight of 16,000 and a weight average molecular weight of 32,000 synthesized from 1,4-butanediol and adipic acid. L-lactide 83.
9 parts by weight, 1.1 parts by weight of D-lactide, and 15 parts by weight of toluene based on the total amount of lactide and aliphatic polyester were placed in a separable flask and melted at 170 ° C. After the solution becomes homogeneous, tin octoate 20
0 ppm was added, and the mixture was stirred at 170 ° C. for 3.5 hours.

The lactic acid-based copolyester obtained was G
PC number average molecular weight 79,000, weight average molecular weight 12
It was confirmed to be a copolymer of 9,000. The glass transition temperature of this polymer is 4 with a differential calorimeter (DSC).
It was 4 ° C.

(Comparative Example 5) (Synthesis of lactic acid-based copolyester) 30 parts by weight of an aliphatic polyester having a number average molecular weight of 16,000 and an average molecular weight of 32,000 synthesized from 1,4-butanediol and adipic acid. L-lactide 69.
1 part by weight, 0.9 part by weight of D-lactide, and 15 parts by weight of toluene based on the total amount of lactide and the aliphatic polyester were placed in a separable flask and melted at 170 ° C. After the solution becomes homogeneous, tin octoate 20
0 ppm was added, and the mixture was stirred at 170 ° C. for 3.5 hours.

The lactic acid-based copolyester obtained was G
PC number average molecular weight 79,000, weight average molecular weight 12
It was confirmed to be a copolymer of 9,000. The glass transition temperature of this polymer is 4 with a differential calorimeter (DSC).
It was 4 ° C.

(Comparative Example 6) (Synthesis of lactic acid type copolyester) G synthesized from 1,5-pentanediol and adipic acid
PC number average molecular weight 32,000, weight average molecular weight 5
30 parts by weight of 7,000 aliphatic polyester, 69.1 parts by weight of L-lactide, 0.9 part by weight of D-lactide,
Take 15 parts by weight of toluene based on the total amount of lactide and polyester in a separable flask equipped with a reflux condenser,
Melted at 170 ° C. After the solution became uniform, 150 ppm of tin octoate was added and stirred. The viscosity increased within 1 hour of the reaction, and the Weisenberg phenomenon was observed after 2 hours.

After 4 hours, when the polymer was cooled to stop the reaction, it became a cloudy and hard resin. This lactic acid-based copolyester has a number average molecular weight of 54,000 as measured by GPC,
It was confirmed to be a copolymer having a weight average molecular weight of 89,000. The glass transition temperature was 40 ° C.

(Comparative Example 7) (Synthesis of lactic acid type copolyester) Synthesized from 1,6-hexanediol and adipic acid.
GPC number average molecular weight 35,000, weight average molecular weight 1
20 parts by weight of 47,000 aliphatic polyester, 80 parts by weight of L-lactide, and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask equipped with a reflux condenser and melted at 170 ° C.

After the solution became uniform, tin octoate 1
50 ppm was added and stirred. The viscosity increased in 1 hour of the reaction, and the reaction was stopped after 4 hours. When the polymer was cooled to stop the reaction, it became a transparent and hard resin. This lactic acid-based copolyester has a number average molecular weight of 38,0 by GPC.
It was confirmed to be a copolymer having a weight average molecular weight of 00 and a weight average molecular weight of 70,000. The glass transition temperature was 56 ° C.

(Comparative Example 8) (Synthesis of lactic acid type copolyester) G synthesized from 1,6-hexanediol and adipic acid
PC number average molecular weight 35,000, weight average molecular weight 14
30 parts by weight of 7,000 aliphatic polyester, 70 parts by weight of L-lactide, and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask equipped with a reflux condenser and melted at 170 ° C. After the solution became uniform, 250 ppm of tin octoate was added and stirred. The viscosity increased in 1 hour of the reaction, and the reaction was stopped after 4 hours.

When the polymer was cooled to stop the reaction, it became a cloudy and hard resin. It was confirmed by GPC that this lactic acid-based copolyester was a copolymer having a number average molecular weight of 40,000 and a weight average molecular weight of 127,000. The glass transition temperature was 48 ° C.

(Comparative Example 9) (Synthesis of lactic acid type copolyester) G synthesized from 1,6-hexanediol and adipic acid
PC number average molecular weight 35,000, weight average molecular weight 14
40 parts by weight of 7,000 aliphatic polyester, 60 parts by weight of L-lactide, and 10 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask equipped with a reflux condenser and melted at 170 ° C. After the solution became uniform, 150 ppm of tin octoate was added and stirred. The viscosity increased in 1 hour of the reaction, and the reaction was stopped after 4 hours.

The weight average molecular weight of this polymer was determined by GPC.
84,000, glass transition temperature 46 ° C, melting point 16
It was 2 ° C. Comparing this result with the results of Examples 14 to 20, it can be seen that the one obtained by copolymerizing the linear polyester with lactide is easily opaque. The glass transition temperature was 45 ° C.

(Comparative Example 10) (Synthesis of lactic acid-based copolyester) Aliphatic polyester synthesized from 1,5-pentanediol and decanedicarboxylic acid with GPC having a number average molecular weight of 14,000 and a weight average molecular weight of 32,000. 30 parts by weight, 70 parts by weight of L-lactide and 15 parts by weight of toluene based on the total amount of lactide and polyester were placed in a separable flask and melted at 170 ° C.

After the solution became uniform, zinc octoate 2
00 ppm was added, and the mixture was stirred at 173 ° C. for 4 hours. It was confirmed by GPC that the obtained polymer was a copolymer having a number average molecular weight of 68,000 and a weight average molecular weight of 112,000. The glass transition temperature was 52 ° C.

(Comparative Example 11) (Synthesis of lactic acid copolymer polyester) Aliphatic polyester synthesized from 1,5-pentanediol and dodecanedioic acid, having a number average molecular weight of 14,000 by GPC and a weight average molecular weight of 32,000. 40 parts by weight, L
60 parts by weight of lactide and 15 parts by weight of toluene with respect to the total amount of lactide and polyester were taken in a separable flask and melted at 170 ° C. After the solution became homogeneous, zinc octoate (200ppm) was added at 173 ° C.
It was stirred for 4 hours. It was confirmed by GPC that the obtained polymer was a copolymer having a number average molecular weight of 55,000 and a weight average molecular weight of 79,000. Glass transition temperature is 52
It was ℃.

The results are shown in Tables 1 to 6.

[0127]

[Table 1]

[0128]

[Table 2]

[0129]

[Table 3]

[0130]

[Table 4]

[0131]

[Table 5]

[0132]

[Table 6]

[0133]

INDUSTRIAL APPLICABILITY The present invention can provide a method for producing a lactic acid-based copolyester having excellent transparency and moldability while having excellent biodegradability.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hori Kakizawa 818-3-404, Sono-cho, Inage-ku, Chiba-shi, Chiba (56) Reference JP-A-10-252622 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (9)

(57) [Claims] 1. The total number of carbon atoms of methylene or methine in the main chain of a diol residue and a dicarboxylic acid residue is 4 or more,
And an aliphatic polyester (A1) having a branched chain consisting of an alkyl group having 1 to 10 carbon atoms, which may have a double bond and / or an ether bond oxygen atom, and a lactide (B) are opened. A method for producing a transparent lactic acid-based copolyester, which comprises copolymerizing in the presence of a polymerization catalyst. 2. A diol residue having a branched chain of an alkyl group having 1 to 10 carbon atoms, which may have a double bond and / or an ether bond oxygen atom in the aliphatic polyester (A1), and The total amount of the / or dicarboxylic acid residues is 15 to 100 mol% of all the diol residues and / or dicarboxylic acid residues in the aliphatic polyester (A1), and the production method according to claim 1. 3. The production method according to claim 1, wherein the weight ratio of the aliphatic polyester (A1) and the lactide (B) is in the range of 80:20 to 2:98. 4. The aliphatic diol, which is a constituent of the aliphatic polyester (A1), has a main chain which is an alkyl or alkene having 2 to 12 carbon atoms. The manufacturing method described in. 5. The main chain of an aliphatic dicarboxylic acid which is a constituent of the aliphatic polyester (A1) is an alkyl or alkene having 2 to 18 carbon atoms.
5. The manufacturing method according to any one of 1 to 4. 6. The production method according to claim 1, wherein the aliphatic polyester (A1) is an aliphatic polyester having a high molecular weight with an acid anhydride or an isocyanate. 7. An aliphatic polyester (A1), a lactide (B), and a linear aliphatic polyester (A
The method according to any one of claims 1 to 6, characterized in that the copolymerization is carried out in the presence of a ring-opening polymerization catalyst in combination with 2). 8. Aliphatic polyesters (A1) and (A
The manufacturing method according to claim 7, wherein the main chain of the aliphatic diol which is the constituent component of 2) is an alkyl or alkene having 2 to 12 carbon atoms. 9. Aliphatic polyesters (A1) and (A
The main chain of the aliphatic dicarboxylic acid which is the constituent component of 2) is an alkyl or alkene having 2 to 18 carbon atoms, and the production method according to claim 7 or 8.