JP2003268125A - Transparent material for packaging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material for packaging such as a sheet or film, that is made of a lactic acid copolyester having transparency and moldability, and that has excellent biodegrability. <P>SOLUTION: A transparent lactic acid copolyester is obtained by copolymerizing an aliphatic polyester (A1) having a branched chain of a 1-10C alkyl group wherein the total of the metlylene or methine carbons is 4 or more in the main chain composed of a diol residue and a dicarboxylic acid residue, and a double bond and/or an oxygen atom in an ether bond may be involved, with a lactide (B), in the presence of a ring-opening polymerization catalyst. A transparent material for packaging having a haze of ≤20% at a thickness of 250 μm is molded from the copolyester. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material having excellent transparency and biodegradability obtained by molding a lactic acid-based copolyester obtained by a specific production method.

[0002]

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.

[0003] US Pat. No. 5,202,413 describes a softening of polylactide by copolymerizing lactide with polyethylene adipate having a number average molecular weight of 3,400 or polycaprolactone having a number average molecular weight of 2,000. 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.

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.

When a polyester having a weight average molecular weight of 30,000 or less is used in a copolymerization 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. A lactic acid-based copolyester having sufficient strength and good moldability is required as a raw material for packaging materials.

[0007]

Therefore, the problem to be solved by the present invention is to provide a sheet or film made of a lactic acid-based copolyester having excellent transparency and moldability while having excellent biodegradability. To provide a versatile packaging material such as.

[0008]

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.

[0010]

[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 lactide (B) in the presence of a ring-opening polymerization catalyst, and a method for producing a transparent lactic acid-based copolyester, and a lactic acid-based copolyester produced by the production method. A transparent packaging material having a film thickness of 250 μm and a haze of 20% or less.

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).
It is the said packaging material characterized by being 100 mol%.

More specifically, the aliphatic polyester (A
1) and the lactide (B) are in a weight ratio of 80:20 to 2:98, and the main chain of the aliphatic diol which is a constituent of the aliphatic polyester (A1) has a carbon number. A packaging material which is 2 to 12 alkyls or alkenes.

Further, in these packaging materials, 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, the packaging material of the present invention comprises the aliphatic polyester (A1) and the lactide (B) in combination with a linear aliphatic polyester (A2), which is used in the presence of a ring-opening polymerization catalyst. It includes a packaging material that polymerizes.

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 the main chain of the aliphatic dicarboxylic acid that is a constituent of the aliphatic polyesters (A1) and (A2) is an alkyl or alkene having 2 to 18 carbon atoms.

The lactide and polyester used in the packaging material 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 used in the present invention
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. 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 branched polyester having a branched chain is soluble in tetrahydrofuran, acetone, toluene, benzene, ethylbenzene, xylene, dioxane, chloroform, dichloromethane, chlorobenzene, etc., and broadens the solvent selection range in the copolymerization reaction, and the reaction yield Is preferable in terms of improving

Examples of the branched dicarboxylic acid of the aliphatic polyester include methyl succinic acid, dimethyl succinic acid, ethyl succinic acid, 2-methyl glutaric acid, 2-ethyl glutaric acid, 3-methyl glutaric acid, 3-ethyl glutaric 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 copolyester 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 are used with respect to the whole, depending on the 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 organometallic 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 carboxylic acid anhydride or isocyanate with the reaction product immediately after the polymerization reaction of the polyester between the diol and the dicarboxylic acid is completed and then melting 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 anhydride or isocyanate and reacted 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 method for producing the lactic acid-based copolyester used in the present invention will be described in order. The molar ratio of diol and dicarboxylic acid is 1.4: 1 and the ratio is 130 in a nitrogen atmosphere.
Water is distilled off by stirring while gradually raising the temperature from 5 ° C to 220 ° C at a rate of 5 to 10 ° C per hour. 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, excess glycol is distilled off while gradually increasing the degree of vacuum at 10 to 0.5 torr.

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 less, preferably 180 ° C. or less 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 used in the present invention can be produced by using an ordinary reaction kettle, but an ordinary reaction kettle is used in order to increase the viscosity accompanying the increase in molecular weight. In the above-mentioned copolymerization reaction, stirring efficiency is lowered, which causes coloring due to local heating and a reduction in 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.

Although this reaction can be carried out only with a static mixer, it is more preferable to use a normal 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 is characterized in that it has transparency after being melted and allowed to cool at room temperature. That is, even if a lactic acid-based copolyester obtained by a production method other than the above-mentioned production method, a transparent one is obtained when a sheet or film is prepared by rapidly cooling the polymer after melting, but whitening occurs with the passage of time. , 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 used 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 used in the present invention has a glass transition temperature of 20 ° C to 60 ° C. In the lactic acid-based copolyester used in 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 40
℃ or above.

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 lower obtained by the above method 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. Slow cooling with crystallization partially promotes lactide and haze of sheet is 1
It becomes 0 to 20% and the transparency is slightly lowered.

The lactic acid-based copolyester obtained by the above-mentioned production method has good biodegradability, and even when it is dumped in the sea, it is decomposed by hydrolysis, biodegradation or 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 packaging material of the present invention is obtained by molding the transparent lactic acid-based copolyester obtained above. Examples of the molding method include various methods such as blow molding, extrusion molding, injection molding, inflation molding, laminate molding, press molding, and extrusion foam molding. 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. Is mentioned.

[0054]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples.

(Synthesis 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 1) (Preparation of lactic acid-based copolyester sheet) The lactic acid-based copolyester obtained in Synthesis Example 1 was used at 60 ° C.
And dried under reduced pressure for 6 hours. 3.3 g of this polymer and 1
250 μm thick with a square of 0 cm x 10 cm
The PET sheet of 1 was sandwiched between PET sheets having a thickness of 100 μm, and was pressed at a pressure of 200 kg / cm ² for 1 minute while being heated and melted at 170 ° C.

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 Synthesis 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 1 A sheet was molded from the lactic acid-based copolyester synthesized in Comparative Synthesis Example 1 in the same manner as in Example 1. When the obtained sheet was left at room temperature, it became a translucent sheet having a haze of 25% and a transmittance of 60%. It can be seen that the sheet of the copolymer obtained by copolymerizing the polyester having the branched chain has higher transparency.

[0062]

EFFECT OF THE INVENTION The packaging material of the present invention has excellent biodegradability, yet sufficient transparency and moldability.

Continuation of front page (51) Int.Cl. ⁷ identification code FI theme code (reference) C08L 67:00 C08L 67:00 (72) Inventor Hori Kakizawa 1-9-13 Midorigaoka, Toyonaka City, Osaka Prefecture (reference) ) 3E086 AB01 AB02 AD01 AD05 AD06 AD07 AD13 BA15 BB21 BB90 4F071 AA43 AF01 AF30 AH04 AH05 BA01 BB03 BB05 BB06 BB09 BC01 BC04 BC12 BC17 4J029 AA05 AC02 AD10 AE01 BA02 BA09 BA05 BA04 BA05 BA07 BA07 BA05 BA07 BA07 BA07 BA05 BA07 BA07 BA05 BA07 BA07 BA07 BA07 GA13 GA14 GA15 JB171 JC152 JF181 JF321 JF331 JF371 KE02 4J200 AA28 BA03 BA05 BA10 BA17 BA19 BA20 CA01 DA17 EA04 EA11

Claims (9)

[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 transparent lactic acid-based copolyester obtained by copolymerization in the presence of a polymerization catalyst is molded,
A transparent packaging material having a film thickness of 250 μm and a haze of 20% or less. 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 packaging material according to claim 1, wherein the total amount of the / or dicarboxylic acid residues is 15 to 100 mol% of all the diol residues and / or the dicarboxylic acid residues in the aliphatic polyester (A1). 3. The packaging material 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 packaging material according to claim 1, wherein the main chain of the aliphatic diol which is a constituent component of the aliphatic polyester (A1) is an alkyl or alkene having 2 to 12 carbon atoms. . 5. The packaging according to claim 1, wherein the main chain of the aliphatic dicarboxylic acid which is a constituent component of the aliphatic polyester (A1) is an alkyl or alkene having 2 to 18 carbon atoms. material. 6. The packaging material 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
2) is used in combination and copolymerized in the presence of a ring-opening polymerization catalyst,
The packaging material according to any one of claims 1 to 6. 8. Aliphatic polyesters (A1) and (A
The packaging material 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 packaging material according to claim 7 or 8, wherein the main chain of the aliphatic dicarboxylic acid that is the constituent component of 2) is an alkyl or alkene having 2 to 18 carbon atoms.