JP2018021103A - Polyester resin composition, film obtained by molding the resin composition, and bag obtained by molding the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition excellent not only in tensile strength but also in tear strength when molded into a film, and to provide a film and a bag obtained by molding the resin composition.SOLUTION: A polyester resin composition contains a polyester resin (A) which is an aliphatic polyester resin and contains 87 mol% or more of a succinic acid unit in all of the aliphatic dicarboxylic acid unit, a polyester resin (B) which is an aromatic aliphatic copolymerization polyester resin and contains 5 mol% or more and 95 mol% or less of the aromatic dicarboxylic acid unit in all of the dicarboxylic acid unit, a polyester resin (C) containing an aliphatic oxycarboxylic acid, and cellulose ester (D).SELECTED DRAWING: None

Description

  The present invention relates to a resin composition containing an aliphatic polyester-based resin that can provide a film having excellent mechanical properties.

  Conventionally, paper, plastic film, metal foil, etc. have been used in a wide range of applications such as liquids and granules for various foods, medicines, miscellaneous goods, packaging materials for solids, agricultural materials, and building materials. . In particular, plastic films are excellent in strength, water resistance, moldability, transparency, cost, etc., and are used in many applications as bags and containers. Examples of typical plastic films include those made of polyethylene, polypropylene, polystyrene, polyvinyl chloride, and the like. However, these resins are difficult to decompose in a natural environment, and there are problems such as generation of harmful gases and damage to the incinerator when incineration is performed.

  Various resins have been studied to solve the above problems. For example, aliphatic polyester resins such as polybutylene succinate and polybutylene succinate adipate, aliphatic oxycarboxylic acid resins such as polylactic acid, and aromatic aliphatic copolymer polyesters such as polybutylene adipate terephthalate A technique for solving the above problem by using a resin is known (see, for example, Patent Document 1).

  In addition, aromatic aliphatic copolymer polyester resins such as polybutylene adipate terephthalate have been known to improve biodegradability by the presence of aliphatic units between aromatic units, but are formed into films. In this case, as a resin composition excellent in tear strength while maintaining high impact strength, an aliphatic polyester resin containing a predetermined amount of a structural unit derived from succinic acid, and an aromatic having a low aromatic dicarboxylic acid component content An aliphatic polyester-based resin composition containing an aliphatic copolymerized polyester-based resin and an aliphatic oxycarboxylic acid-based resin in a predetermined ratio is disclosed (for example, see Patent Document 2).

Special table 2001-500907 JP2013-040321A

  Aliphatic polyester resins such as polybutylene succinate and polybutylene succinate adipate have a high crystallization rate and good moldability, but the tear strength of the film after molding may be insufficient. It was. In the technique described in Patent Document 2, the succinic acid unit in all the dicarboxylic acid units in the aliphatic polyester-based resin such as polybutylene succinate and polybutylene succinate adipate is used as a specific ratio, The aliphatic oxycarboxylic acid resin such as polybutylene adipate terephthalate and other aliphatic aliphatic copolyester resins are included at a predetermined ratio to improve the tear strength. However, there was a case where the film became so-called waistless.

This invention makes it a subject to provide the film and bag which shape | mold the resin composition which is excellent in the tensile strength and is also excellent in tearing strength, when shape | molded in a film, and the said resin composition.

  As a result of intensive studies to solve the above problems, the present inventor has determined that the succinic acid units in all the dicarboxylic acid units have a specific ratio of polyester resin (A), polyester resin (B), and polyester resin (C). In addition to the above, it has been found that by containing a specific cellulose ester (D), a film having excellent tensile strength and improved tear strength can be obtained.

That is, the gist of the present invention is the following [1] to [5].
[1] An aliphatic polyester-based resin containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, the polyester resin (A) containing 87 mol% or more of succinic acid units in all aliphatic dicarboxylic acid units, Aromatic aliphatic copolymerized polyester-based resin containing an aromatic diol unit, an aliphatic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit, wherein the aromatic dicarboxylic acid unit in the total dicarboxylic acid unit is 5 mol% or more and 95 mol% One or more types of cellulose ester (D) selected from the group consisting of polyester resin (B), polyester resin (C) containing aliphatic oxycarboxylic acid, and cellulose triacetate, cellulose acetate propionate and cellulose acetate butyrate ) Containing a polyester resin composition.
[2] The resin composition according to [1], wherein the cellulose ester (D) is cellulose acetate propionate.
[3] A film obtained by molding the resin composition according to [1] or [2].
[4] A multifilm obtained by molding the resin composition according to [1] or [2].
[5] A bag obtained by molding the film according to [3].

ADVANTAGE OF THE INVENTION According to this invention, when a moldability is favorable and it is set as a film, while being excellent in tensile strength, the resin composition which is excellent also in tear strength can be provided.
For example, when the resin composition according to the present invention is formed into a film and then formed into a bag, it has excellent tear strength and can prevent the bag from tearing. Moreover, it becomes possible to prevent tearing of a bag by being excellent in tensile strength. Furthermore, the multifilm obtained by shape | molding the resin composition which concerns on this invention is excellent in tear strength, and can be used suitably.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.
The polyester resin composition of the present invention contains the following polyester resins (A) to (C) and a cellulose ester (D). The polyester resin (A) is an aliphatic polyester resin containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, and is a polyester containing 87 mol% or more of succinic acid-derived units in all aliphatic dicarboxylic acid-derived units. Resin. The polyester resin (B) is an aromatic aliphatic copolymerized polyester-based resin containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit. It is a polyester resin containing 5 mol% or more and 95 mol% or less of an acid unit. The polyester resin (C) is a polyester resin containing an aliphatic oxycarboxylic acid. Furthermore, the polyester resin composition of the present invention contains one or more cellulose esters (D) selected from the group consisting of cellulose triacetate, cellulose acetate propionate, and cellulose acetate butyrate.

In the present invention, an aliphatic diol refers to an aliphatic hydrocarbon group having two hydroxyl groups bonded. As the aliphatic hydrocarbon group, a straight chain aliphatic hydrocarbon group is usually used, but it has a branched structure. May have a ring structure, or may have a plurality of them. In addition, the aliphatic dicarboxylic acid unit refers to an aliphatic hydrocarbon group in which two carboxyl groups are bonded. As the aliphatic hydrocarbon group, a straight chain aliphatic hydrocarbon group is usually used. May have a ring structure, or may have a plurality of them.

  The polyester resin according to the present invention is a polymer having repeating units, and each repeating unit is also referred to as a compound unit for the compound from which each repeating unit is derived. Specifically, for example, a repeating unit derived from an aliphatic diol is an “aliphatic diol unit”, a repeating unit derived from an aliphatic dicarboxylic acid is an “aliphatic dicarboxylic acid unit”, and a repeating unit derived from an aromatic dicarboxylic acid is The “aromatic dicarboxylic acid unit” and the repeating unit derived from the aliphatic oxycarboxylic acid are also referred to as “aliphatic oxycarboxylic acid unit”.

1. Polyester resin composition The resin composition of the present invention is a resin composition characterized by containing a polyester resin (A), a polyester resin (B), a polyester resin (C), and a cellulose ester (D).
When formed into a film using the polyester resin composition of the present invention, the film can be made excellent in formability, tensile strength and tear strength.

  Moreover, since these physical properties can be made more excellent, the content ratio of the polyester resin (A) is preferably 5% by weight or more, more preferably 10% by weight or more, and particularly preferably Is 15% by weight or more. For the same reason, the content ratio of the polyester resin (B) is preferably 5% by weight or more, more preferably 10% by weight or more, and particularly preferably 15% by weight or more. For the same reason, the content ratio of the polyester resin (C) is preferably 1% by weight or more, more preferably 3% by weight or more, and particularly preferably 5% by weight or more. The content ratio of the compound (D) is preferably 0.1% by weight or more, more preferably 1% by weight or more, and particularly preferably 5% by weight or more.

Further, when a film is formed using the resin composition according to the present invention, it is possible to further improve the tear strength of the film and the impact strength of the film, so that the polyester resin (A), the polyester resin It is preferable that the polyester resin (C) is 1 to 20% by weight, more preferably 3 to 15% by weight, particularly preferably 5 to 10% by weight based on the total of (B) and the polyester resin (C). To do.
The polyester resin composition of the present invention may contain various compounds other than the polyester resin (A), the polyester resin (B), the polyester resin (C), and the cellulose ester (D). These other components will be described later.

1.1. Polyester resin (A)
The polyester resin (A) used in the present invention is an aliphatic polyester-based resin containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, and succinic acid-derived units are 87 mol% in all aliphatic dicarboxylic acid-derived units. Contains above. The polyester resin (A) may be a mixture of polyester resins having different amounts of succinic acid units, for example, an aliphatic polyester-based resin not containing dicarboxylic acid structural units other than those derived from succinic acid, and those other than those derived from succinic acid. It is also possible to blend with an aliphatic polyester-based resin containing a structural unit and adjust the amount of succinic acid-derived structural units in the polyester resin (A) within the above predetermined range.

More specifically, the polyester resin (A) is a polyester resin containing an aliphatic diol unit represented by the following formula (1) and an aliphatic dicarboxylic acid unit represented by the following formula (2).
—O—R ¹ —O— (1)
^-OC-R 2 -CO- (2)
In formula (1), R ¹ represents a divalent aliphatic hydrocarbon group. When the polyester resin (A) is a copolymer, the polyester resin (A) may contain two or more types of aliphatic diol units represented by the formula (1). In the formula (2), R ² is a divalent aliphatic hydrocarbon group. The aliphatic diol unit and the aliphatic dicarboxylic acid unit represented by the above formulas (1) and (2) may be derived from a compound derived from petroleum or a compound derived from a plant raw material. Although not desirable, it is desirable to include compounds derived from plant materials. When the polyester resin (A) is a copolymer, the polyester resin (A) may contain two or more aliphatic dicarboxylic acid units represented by the formula (2). The aliphatic dicarboxylic acid unit represented by the formula (2) contains 87 mol% or more of structural units derived from succinic acid based on the total aliphatic dicarboxylic acid unit. By setting the structural unit amount derived from succinic acid in the polyester resin (A) within a predetermined range, it is possible to obtain a film having a high elastic modulus excellent in tensile strength. For the same reason, the structural unit derived from succinic acid is preferably contained in an amount of 87 mol% or more, more preferably 90 mol% or more, still more preferably 93 mol% or more, based on the total aliphatic dicarboxylic acid unit. .

  Although it does not specifically limit as aliphatic diol which gives the diol unit of Formula (1), From a viewpoint of a moldability or mechanical strength, a C2-C10 aliphatic diol is preferable, C4-C6 is preferable. Aliphatic diols are particularly preferred. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like can be mentioned, among which 1,4-butanediol is particularly preferable. Two or more kinds of the aliphatic diols can be used.

  Although it does not specifically limit as a dicarboxylic acid component which gives the dicarboxylic acid unit of Formula (2), C2-C40 aliphatic dicarboxylic acid is preferable, C4-C10 aliphatic dicarboxylic acid is especially preferable. preferable. For example, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid and the like can be mentioned, among which adipic acid and sebacic acid are preferable, and adipic acid is particularly preferable. Two or more kinds of the dicarboxylic acids can be used.

  Furthermore, the polyester resin (A) in the present invention may have a repeating unit (aliphatic oxycarboxylic acid unit) derived from an aliphatic oxycarboxylic acid. Specific examples of the aliphatic oxycarboxylic acid that gives an aliphatic oxycarboxylic acid unit include, for example, lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy- Examples include 3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid and the like, or lower alkyl esters or intramolecular esters thereof. When optical isomers exist in these, any of D-form, L-form and racemic form may be sufficient, and the form may be solid, liquid, or aqueous solution. Of these, lactic acid or glycolic acid is particularly preferred. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more.

The amount of the aliphatic oxycarboxylic acid unit is preferably 20 mol% or less, more preferably 10 mol% or less, particularly preferably in all repeating units constituting the polyester resin (A) from the viewpoint of moldability. 5 mol% or less.
The polyester resin (A) in the present invention is “trifunctional or higher aliphatic polyhydric alcohol”, “trifunctional or higher aliphatic polyvalent carboxylic acid or acid anhydride thereof” or “trifunctional or higher aliphatic polyvalent alcohol”. By copolymerizing “oxycarboxylic acid”, the melt viscosity may be increased, or the chain length may be extended by a coupling agent.

Specific examples of the trifunctional aliphatic polyhydric alcohol include trimethylolpropane and glycerin, and specific examples of the tetrafunctional aliphatic polyhydric alcohol include pentaerythritol. These may be used alone or in combination of two or more.
Specific examples of the trifunctional aliphatic polyvalent carboxylic acid or its acid anhydride include propanetricarboxylic acid or its acid anhydride, and specific examples of the tetrafunctional polyvalent carboxylic acid or its acid anhydride include: Examples include cyclopentanetetracarboxylic acid or acid anhydrides thereof. These may be used alone or in combination of two or more.

  In addition, the trifunctional aliphatic oxycarboxylic acid includes (i) a type having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) one carboxyl group and two hydroxyl groups. Any type can be used, but from the viewpoint of moldability, mechanical strength and appearance of the molded product, (i) two carboxyl groups and one hydroxyl group such as malic acid are contained in the same molecule. The type which has is preferable, and, specifically, malic acid is preferably used. In addition, the tetrafunctional aliphatic oxycarboxylic acid component includes (i) a type in which three carboxyl groups and one hydroxyl group are shared in the same molecule, and (ii) two carboxyl groups and two hydroxyl groups. A group that shares a group in the same molecule; (iii) a group that shares three hydroxyl groups and one carboxyl group in the same molecule, and any type can be used. What has two or more is preferable and a citric acid, tartaric acid, etc. are mentioned more specifically. These may be used alone or in combination of two or more.

The amount of the structural unit derived from such a tri- or higher functional component is 100 mol% based on all structural units constituting the polyester resin (A), and the lower limit is usually 0 mol% or more, preferably 0.01 mol% or more. The upper limit is usually 5 mol% or less, preferably 2.5 mol% or less.
Examples of the coupling agent include diisocyanate, oxazoline, diepoxy compound, acid anhydride, and the like. Specifically, 2,4-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, hydrogen Xylylene diisocyanate, hexamethylene diisocyanate and the like. These addition amounts are 0.1-5 weight part with respect to 100 weight part of polyester resins (A).

The polyester resin (A) has a structural unit derived from succinic acid, has a structural unit derived from the dicarboxylic acid component other than succinic acid, and a structural unit derived from the diol component, and has a structure derived from the polyhydric alcohol component. A unit, a structural unit derived from the polyvalent carboxylic acid component, a structural unit derived from an aliphatic oxycarboxylic acid component, and a coupling agent are optionally included.
The polyester resin (A) used in the present invention can be produced by a known method. For example, a general method of melt polymerization in which the above-mentioned aliphatic dicarboxylic acid containing succinic acid and an aliphatic diol are esterified and / or transesterified, followed by a polycondensation reaction under reduced pressure, Although it can also be produced by a known solution heating dehydration condensation method using an organic solvent, a method of production by melt polymerization carried out in the absence of solvent is preferred from the viewpoint of economy and simplicity of the production process.

  The average molecular weight of the polyester resin (A) can be measured by gel permeation chromatography (GPC), and the weight average molecular weight using polystyrene as a standard substance is usually 10,000 or more and 1,000,000 or less. However, since it is advantageous in terms of moldability and mechanical strength, it is preferably 20,000 or more and 500,000 or less, more preferably 50,000 or more and 400,000 or less.

The melt flow rate (MFR) of the polyester resin (A) is usually 0.1 g / 10 min or more and usually 100 g / 10 min or less when measured at 190 ° C. and 2.16 kg. From the viewpoint of moldability and mechanical strength, it is preferably 50 g / 10 min or less, particularly preferably 30 g /
10 minutes or less.
The melting point of the polyester resin (A) is preferably 70 ° C. or higher, more preferably 75 ° C. or higher, preferably 170 ° C. or lower, more preferably 119 ° C. or lower, particularly preferably lower than 100 ° C. When there are a plurality of melting points, at least one melting point is preferably within the above range. The elastic modulus is preferably 180 to 500 MPa. When the melting point is out of the range, the moldability is inferior, when the elastic modulus is 180 MPa or less, problems easily occur in the moldability and bag-making property, and when the elastic modulus is 500 MPa or more, it is difficult to obtain the effect of improving the tear strength and impact strength. The method for adjusting the melting point and elastic modulus of the polyester resin (A) is not particularly limited. For example, the type of copolymerization component other than succinic acid can be selected, the copolymerization ratio of each can be adjusted, It can be adjusted by combining them.

1.2. Polyester resin (B)
The polyester resin (B) used in the present invention is an aromatic aliphatic copolymer polyester resin containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit. Specifically, for example, an aliphatic diol unit represented by the following formula (3), an aliphatic dicarboxylic acid unit represented by the following formula (4), and an aroma represented by the following formula (5) The main component is an aromatic aliphatic copolyester composed of an aromatic dicarboxylic acid unit, and preferably has biodegradability.

—O—R ³ —O— (3)
In formula (3), R ³ represents a divalent aliphatic hydrocarbon group. When the polyester resin (B) is a copolymer, two or more kinds of R ³ may be contained in the polyester resin (B).
—OC—R ⁴ —CO— (4)
In formula (4), R ⁴ represents a divalent aliphatic hydrocarbon group. When the polyester resin (B) is a copolymer, two or more kinds of R ⁴ may be contained in the polyester resin (B).

—OC—R ⁵ —CO— (5)
In formula (5), R ⁵ represents a divalent aromatic hydrocarbon group. When the polyester resin (B) is a copolymer, two or more kinds of R ⁵ may be contained in the polyester resin (B).
The diol giving the diol unit of the formula (3) is not particularly limited, but those having 2 to 10 carbon atoms are preferred from the balance of cost and mechanical strength. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like can be mentioned. Among these, diols having 2 to 4 carbon atoms are preferable, ethylene glycol and 1,4-butanediol are more preferable, and 1,4-butanediol is particularly preferable.

The dicarboxylic acid that gives the dicarboxylic acid unit of the formula (4) is not particularly limited, but those having 2 to 12 carbon atoms are preferable from the balance between cost and biodegradability. For example, succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid and the like can be mentioned. Of these, sebacic acid or adipic acid is preferred.
As the aromatic dicarboxylic acid that gives the aromatic dicarboxylic acid unit of the formula (5), the ring structure of R ⁵ is preferably 2 or less, and more specifically, for example, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, etc. Among them, from the viewpoint of biodegradability, R ⁵ is preferably a phenylene group, and more specifically, for example, terephthalic acid and isophthalic acid are preferable, and terephthalic acid is particularly preferable. Moreover, the aromatic dicarboxylic acid by which a part of aromatic ring was substituted by the sulfonate may be sufficient.

Two or more types of aliphatic dicarboxylic acids, aliphatic diols, and aromatic dicarboxylic acids can be used.
The polyester resin (B) may have an aliphatic oxycarboxylic acid unit. Specific examples of the aliphatic oxycarboxylic acid that gives an aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3, Examples include 3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, or a mixture thereof. Further, these lower alkyl esters or intramolecular esters may be used. When optical isomers exist in these, any of D-form, L-form and racemic form may be sufficient, and the form may be any of solid, liquid or aqueous solution. Among these, lactic acid or glycolic acid is preferable. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more.

The amount of the aliphatic oxycarboxylic acid is preferably 20 mol% or less, more preferably 10 mol% or less, in all the components constituting the polyester resin (B).
The polyester resin (B) is similar to the polyester resin (A) in that “trifunctional or higher aliphatic polyhydric alcohol”, “trifunctional or higher aliphatic polyvalent carboxylic acid or acid anhydride thereof” or “trifunctional” is used. The melt viscosity may be increased by copolymerizing the above `` aliphatic polyvalent oxycarboxylic acid '', and the chain length may be extended by a coupling agent such as diisocyanate or diepoxy compound. May be.

  The content of the aromatic dicarboxylic acid unit in the polyester resin (B) is preferably from the viewpoint of the melting point and biodegradability with respect to the total (100 mol%) of the aliphatic dicarboxylic acid unit and the aromatic dicarboxylic acid unit. It is 5 mol% or more, more preferably 35 mol% or more, particularly preferably 40 mol% or more, preferably 95 mol% or less, more preferably 65 mol% or less, and particularly preferably 60 mol% or less.

A polyester resin (B) can be manufactured by a well-known manufacturing method similarly to the said polyester resin (A).
The average molecular weight of the polyester resin (B) can be measured by gel permeation chromatography (GPC), and the weight average molecular weight using polystyrene as a standard substance is usually 5,000 or more and 1,000,000 or less. However, since it is advantageous in terms of moldability and mechanical strength, it is preferably 10,000 or more and 500,000 or less.

  When the melt flow rate (MFR) of the polyester resin (B) used in the present invention is measured at 190 ° C. and 2.16 kg, the lower limit is usually 0.1 g / 10 min or more, and the upper limit is usually 100 g / 10 min. It is preferable that it is below, More preferably, it is 50 g / 10min or less, Most preferably, it is 30 g / 10min or less. The melt flow rate (MFR) of the polyester resin (B) can be adjusted by the molecular weight.

  The melting point of the polyester resin (B) is preferably 70 ° C. or higher, more preferably 75 ° C. or higher, preferably 205 ° C. or lower, more preferably 180 ° C. or lower, particularly preferably 140 ° C. or lower. If the melting point is 70 ° C. or lower, the moldability and heat resistance of the composition are poor, and if it is 205 ° C. or higher, the melting point difference from other components becomes large and the moldability is poor. The melting point of the polyester resin (B) can be adjusted by the amount of aromatic dicarboxylic acid or oxycarboxylic acid.

1.3. Polyester resin (C)
The polyester resin (C) used in the present invention is mainly composed of a polyester resin composed of aliphatic oxycarboxylic acid units.
Examples of the aliphatic oxycarboxylic acid that gives an aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, and 5-hydroxy. Valeric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 3-hydroxyhexanoic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, etc. Or these lower alkyl ester or intramolecular ester is mentioned. When optical isomers exist in these, any of D-form, L-form and racemic form may be sufficient, and the form may be solid, liquid, or aqueous solution. Among these, lactic acid or glycolic acid is particularly preferable, and lactic acid is most preferable. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more.

  Moreover, the polyester resin (C) may have an aliphatic oxycarboxylic acid unit derived from a trifunctional or higher functional aliphatic oxycarboxylic acid component. The trifunctional aliphatic oxycarboxylic acid component includes (i) a type having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) a type having one carboxyl group and two hydroxyl groups. Any type can be used, but from the viewpoint of improving the quality by reducing coloring and foreign matter of the polyester resin (C), (i) two carboxyl groups such as malic acid and a hydroxyl group Is preferably a type having one in the same molecule, and more specifically, malic acid or the like is preferably used. In addition, the tetrafunctional aliphatic oxycarboxylic acid component includes (i) a type in which three carboxyl groups and one hydroxyl group are shared in the same molecule, and (ii) two carboxyl groups and two hydroxyl groups. It is divided into a type sharing a group in the same molecule, and (iii) a type sharing three hydroxyl groups and one carboxyl group in the same molecule, and any type can be used. Specific examples include citric acid and tartaric acid. These may be used alone or in combination of two or more.

  The polyester resin (C) may contain other structural units derived from the aliphatic polyester or aromatic aliphatic polyester as described above. The content of the other structural unit in the polyester resin (C) is 100 mol% in total of the structural unit derived from the aliphatic oxycarboxylic acid and the other structural unit, and the lower limit is usually 0 mol% or more, preferably It is 0.01 mol% or more, and an upper limit is 5 mol% or less normally, Preferably it is 2.5 mol% or less.

The polyester resin (C) can be obtained by a method of directly dehydrating polycondensation of the above raw materials, a method of ring-opening polymerization of a cyclic dimer of lactic acid or hydroxycarboxylic acid, production by microorganisms, or the like.
When the melt flow rate (MFR) of the polyester resin (C) used in the present invention is measured at 190 ° C. and 2.16 kg, the lower limit is usually 0.1 g / 10 min or more, and the upper limit is usually 100 g / 10 min. Hereinafter, it is preferably 50 g / 10 min or less, particularly preferably 30 g / 10 min or less.

1.4. Cellulose ester (D)
The resin composition of the present invention contains cellulose ester (D).
The cellulose ester (D) of the resin composition of the present invention is one or more selected from the group consisting of triacetyl cellulose (TAC), cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB). . Among these, cellulose acetate propionate (CAP) is preferable.

The cellulose ester (D) may contain 5 to 40 parts by mass of a plasticizer with respect to 100 parts by mass of the cellulose ester from the viewpoint of improving fluidity and increasing the mechanical strength of the molded body.
As the plasticizer, an adipate plasticizer and a polyester plasticizer excluding phthalate are preferable.
The number average molecular weight of the cellulose ester (D) is preferably in the range of 10,000 to 100,000, more preferably in the range of 15,000 to 80,000, from the viewpoint of maintaining fluidity (processability).

The number average molecular weight can be measured by gel permeation chromatography (GPC).
The melting range of the cellulose ester (D) is preferably 120 ° C. or higher, more preferably 130 ° C. or higher, preferably 250 ° C. or lower, more preferably 240 ° C. or lower, and particularly preferably lower than 230 ° C.

Specific examples of the cellulose ester (D) include CAP-480-20, CAP-482-0.5, CAP-504-0.2, CAB-551-0.01, CAB-551-0.2, CAB-553 manufactured by Eastman Corporation. -0.4, CAB-531-1, CAB-500-5, CAB-381-0.1, CAB-381-0.1, CAB-381-0.5, CAB-381-2, CAB-381-20, CAB-381-20 BP, CAB-321-0.1, CAB-171-15, etc., among which CAP-480-20, CAP-482-0.5
CAP-504-0.2 is preferred.

  The resin composition of the present invention is characterized by containing the polyester resin (A), the polyester resin (B), the polyester resin (C) and the cellulose ester (D). Thereby, in addition to the tensile strength when the resin composition is formed into a film, the tear strength is dramatically improved. The reason is that the cellulose ester (D) is compatible with the polyester resin (A) and also functions as a compatibilizer with the polyester resin (B) and the polyester resin (C). It is presumed that the interfacial interaction was improved. In the resin composition of the present invention, the content of the cellulose ester (D) relative to the total of the polyester resin (A) and the cellulose ester (D) is compatible with the resin (A), and the resin (A) 1 to 60% by weight is preferable, and 3 to 50% by weight is more preferable from the viewpoint of softening and improving the interaction with other resins.

1.5. Other components The resin composition according to the present invention includes lubricants, fillers (fillers), plasticizers, antistatic agents, antioxidants, light stabilizers, ultraviolet absorbers, dyes, pigments, hydrolysis inhibitors, and the like. Various additives, synthetic resin such as polycaprolactone, polyamide, polyvinyl alcohol, animal / plant material fine powder such as starch, paper, wood powder, chitin / chitosan, coconut shell powder, walnut shell powder, or a mixture thereof May be included as “other components”. These can be arbitrarily used as long as the effects of the present invention are not impaired. These may be used alone or in combination of two or more. The amount of these additives is usually 0.01% by weight or more and 40% by weight based on the total amount of the biodegradable resin composition in order not to impair the physical properties of the biodegradable resin composition. It is preferable that it is below wt%.

1.5.1. Lubricant For example, when a lubricant is included in the resin composition according to the present invention, the moldability when the resin composition is made into a film and then molded into a bag can be improved. Moreover, the opening of the bag can be easily opened, and the usability of the bag can be improved. Furthermore, if the opening of the bag is easy to open, the inspection at the time of manufacturing the bag becomes easy.

As the lubricant, known ones can be used without any particular limitation. Specifically, paraffins such as paraffin oil and solid paraffin, higher fatty acids such as stearic acid and palmitic acid, higher alcohols such as palmityl alcohol and stearyl alcohol, calcium stearate, zinc stearate, barium stearate, aluminum stearate, Metal salts of fatty acids such as magnesium stearate and sodium palmitate, fatty acid esters such as butyl stearate, glycerin monostearate and diethylene glycol monostearate, stearamide, methylene bisstearamide, ethylene bisstearamide, oxystearic acid Waxes such as fatty acid amides such as ethylenediamide, methylolamide, oleylamide, stearic acid amide, erucic acid amide, carnauba wax, montan wax, etc. Kind and the like. In addition, a lubricant and wax may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations. Of these, erucic acid amide is particularly preferred. These lubricants are usually used in an amount of 0.01 to 2% by weight, preferably 0.05 to 0.5% by weight in the resin composition.

1.5.2. Filler When the resin composition according to the present invention contains a filler, it can contribute to the stabilization of the film formation by improving the fluidity and crystallization speed of the resin composition, and the reduction of the anisotropy of film mechanical properties. it can. Moreover, when a resin composition is used as a film, blocking between films can be prevented. Alternatively, when the film is formed into a bag, the opening of the bag can be easily opened. Furthermore, the film and the bag can be colored to improve the light shielding property and the light reflecting property.

  Depending on the shape of the filler, there are fibrous, powdery, plate-like, and needle-like fillers, and powdery and plate-like fillers are particularly preferable. As the particulate filler, mineral particles such as talc, zeolite, diatomaceous earth, kaolin, clay, silica, quartz powder, metal carbonate particles such as calcium carbonate, magnesium carbonate, heavy calcium carbonate, calcium silicate, aluminum silicate, silicic acid Metal silicate particles such as magnesium, metal oxide particles such as alumina, silica, zinc oxide and titanium oxide, metal hydroxide particles such as aluminum hydroxide, calcium hydroxide and magnesium hydroxide, barium sulfate and calcium sulfate Examples thereof include metal sulfate particles and carbon particles such as carbon black. Moreover, mica is mentioned as a plate-shaped filler. From the viewpoint of facilitating the opening of the bag and preventing blocking, talc, calcium carbonate, or silica is preferably used. From the viewpoint of coloring the film or bag and improving the light shielding property or light reflecting property. Carbon black or titanium oxide may be used. The dispersion state of the filler in a molded body such as a film or the resin composition is 0.08 to 25 μm, more preferably 0.1 to 5 μm in terms of number average particle diameter. When it deviates from this range, the addition effect of the said filler will become low. A filler may be used individually by 1 type and may be used in mixture of 2 or more types. These fillers are normally used in the resin composition in the range of 0.05 to 40% by weight.

  There is no particular limitation on the hardness of the filler to be used, but if the hardness is too low, physical properties such as rigidity and heat resistance tend to be low, and if it is too high, it tends to cause poor appearance and reduced physical properties of the film strength. Therefore, it is preferable that the hardness is not too high or too low. The upper limit of the hardness (Mohs hardness) of the filler used is preferably 9 or less, and the lower limit is 1 or more, more preferably the upper limit is 8 or less, and the lower limit is 2 or more, and the upper limit is particularly preferably 7 or less. Is 3 or more. The Mohs hardness here refers to a value obtained by rubbing a standard substance with a sample substance and measuring the hardness with or without scratches. The standard substances are as follows. Hardness 1) talc, hardness 2) gypsum, hardness 3) calcite, hardness 4) fluorite, hardness 5) apatite, hardness 6) feldspar, hardness 7) crystal, hardness 8) yellow jade, hardness 9) corundum (steel ball) ), Hardness 10) diamond. More specifically, talc, calcium carbonate, silica, titanium oxide, barium sulfate or the like can be used as the filler. For example, as talc, LMS100, LMR100, PKP80, and PKP53S manufactured by Fuji Talc are available. Can be mentioned. Examples of calcium carbonate include NITOREX30P, NITREX23P, NS # 100, NCC series NITREX30PS, NCC # 2310, NCC # 1010, NCC-V2300, NCC-V1000, and Whiscal A manufactured by Maruo Calcium. It is done. Examples of the silica particles include Nippon Aerosil Co., Ltd., Aerosil 200, Aerosil 300, and the like. As titanium oxide, CR-60, CR-80, CR-68 manufactured by Ishihara Sangyo Co., Ltd. can be used.

1.5.3. Plasticizer If the flowability of the resin composition is poor, a plasticizer may be added. In particular, when a filler is included in the resin composition, the viscosity of the resin composition may increase and the flowability of the resin composition may deteriorate, and this is improved by adding a plasticizer to the resin composition. be able to.
As a plasticizer, a well-known thing can be used without being specifically limited. For example, methyl adipate, diethyl adipate, diisopropyl adipate, di-n-propyl adipate, di-2-ethylhexyl adipate, diisobutyl adipate, dibutyl adipate, diisodecyl adipate, dibutyl diglycol adipate, di-2-ethylhexyl azelate, dibutyl sebacate , Fatty acid esters such as di-2-ethylhexyl sebacate and methylacetyl lysylate, glycerin esters such as triacetin, diethyl maleate, dibutyl maleate, dioctyl maleate, dibutyl fumarate, dioctyl fumarate and other maleic and fumaric acids Esters, adipic acid-1,3-butylene glycol, polyesters such as epoxidized soybean oil, epoxidized esters, trioctyl trimellitate, etc. Limellitic acid ester, triethylene glycol diacetate, tributyl acetyl citrate, glycerin diacetomonopropionate, glycerin diacetomonocaprylate, glycerin diacetomonocaprate, glycerin diacetomonolaurate, glycerin diacetomonooleate, glycerin monoacetomonobe Polyglycerin fatty acid esters such as acetylated monoglycerides such as henate and glycerin monoacetomonostearate, diglycerin acetate, decaglycerin propionate, tetraglycerin caprylate, decaglycerin laurate, decaglycerin oleate and decaglycerin behenate Rosin derivatives and the like. These plasticizers are usually used in the range of 0.05 to 10% by weight in the resin composition.

1.5.4. Antistatic agent Moreover, when an antistatic agent is included in the resin composition according to the present invention, it is possible to improve moldability when the resin composition is formed into a bag after being formed into a film. In addition, handling of the film and the resin becomes easy. Any antistatic agent can be used as long as the effects of the present invention are not significantly impaired. As a specific example, a surfactant type nonionic, cationic or anionic type is preferable.

  Nonionic antistatic agents include glycerin fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, alkyldiethanolamine, hydroxyalkyl monoethanolamine, polyoxyethylene alkylamine, polyoxyethylene alkylamine fatty acid ester alkyldiethanol Amides and the like are listed. Of these, alkyldiethanolamines are preferred.

  Examples of the cationic antistatic agent include tetraalkylammonium salts and trialkylbenzylammonium salts. Examples of the anionic antistatic agent include alkyl sulfonates, alkyl benzene sulfonates, and alkyl phosphates. Of these, alkylbenzene sulfonate is preferable. This is because the kneadability with the resin is good and the antistatic effect is high.

  The amount of the antistatic agent used is arbitrary as long as the effects of the present invention are not significantly impaired. % By weight or less, preferably 3% by weight or less. If it exceeds the above range, the biodegradable resin composition will have surface stickiness and the product value tends to be reduced. On the other hand, if it is below the above range, the effect of improving the antistatic property tends to be reduced.

1.5.5. Other additives Specific examples of starch include corn starch, waxy corn starch, high amylose corn starch, wheat starch, rice starch, potato starch, sweet potato starch, tapioca starch, and pea starch. These are unmodified and modified products. Either can be used. Modification includes all modification methods such as chemical, physical, and biological, and chemical modification includes esterification, etherification, oxidation, reduction, or partial or all of the structural units of carbohydrates (polysaccharides). It shows that it is modified by a chemical reaction such as coupling, dehydration, hydrolysis, dehydrogenation, halogenation, etc., and particularly shows that a hydroxyl group is etherified or esterified. Physical modification means changing physical properties such as changing the crystallinity. Biological degeneration refers to changing a chemical structure or the like using a living organism.

  Examples of the light stabilizer include bis (2,2,6,6-tetramethyl-1 (octyloxy) -4-piperidinyl) ester decaneate, a reaction product of 1,1-dimethylethyl hydroperoxide and octane, bis ( 1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, bis (1,2,2 , 6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate , 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl) -4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine, poly [[6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine -2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] And hindered amine stabilizers. The light stabilizer is preferably used in combination with an ultraviolet absorber, and a combination of a hindered amine stabilizer and an ultraviolet absorber is effective.

  The amount of the light-resistant agent to be mixed is usually 100 ppm or more, preferably 200 ppm or more, and usually 5 parts by weight or less, preferably 1 part by weight or less, more preferably, on a weight basis with respect to the biodegradable resin composition. 0.5 parts by weight or less. Below this range, the effect of the light resisting agent tends to be small. Moreover, when it exceeds this range, the manufacturing cost tends to be high, the heat resistance of the biodegradable resin composition tends to be inferior, and the light-proofing agent tends to bleed out.

  As the ultraviolet absorber, 2- (2H-benzotriazol-2-yl) -4-6-bis (1-methyl-1-phenylethyl) phenol, 2- (4,6-diphenyl-1,3,5) -Triazin-2-yl) -5-[(hexyl) oxy] phenol and the like. As the ultraviolet absorber, it is particularly preferable to use two or more different types of ultraviolet absorbers in combination.

  The amount of the ultraviolet absorber to be mixed is arbitrary as long as the effects of the present invention are not significantly impaired. However, the biodegradable resin composition is usually 100 ppm or more, preferably 200 ppm or more, and usually 5 wt. % Or less, preferably 2% by weight or less, more preferably 0.5% by weight or less. Below this range, the effect of the ultraviolet absorber tends to decrease. Moreover, when it exceeds this range, the manufacturing cost tends to be too high, the heat resistance of the biodegradable resin composition is inferior, or the ultraviolet absorber bleeds out.

Examples of the heat stabilizer include dibutylhydroxytoluene (BHT; 2,6-di-t-butyl-4-methylphenol), 2,2′-methylenebis (4-methyl-6-t-butylphenol), pentaerythritol tetrakis [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″ -(Mesitylene-2,4,6-triyl) tri-p-cresol, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris [(4 -Tert-butyl-3-hydroxy-
2,6-Xylyl) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris (3,5-di-tert-butyl- 4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, calcium diethylbis [[3,5-bis (1,1-dimethylethyl) -4- Hydroxyphenyl] methyl] phosphonate, bis (2,2′-dihydroxy-3,3′-di-tert-butyl-5,5′-dimethylphenyl) ethane, N, N′-hexane-1,6-diylbis [ Hindered phenol heat stabilizers such as 3- (3,5-di-tert-butyl-4-hydroxyphenylpropionamide; tridecyl phosphite, diphenyl decyl phosphite, tetrakis (2,4-di -Tert-butylphenyl) [1,1-biphenyl] -4,4'-diylbisphosphonite, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester Phosphorous heat stabilizers such as acid, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite; 3-hydroxy-5,7-di-tert-butyl-furan-2-one and xylene Lactone-based heat stabilizers such as reactive organisms; sulfur-based antioxidants such as dilauryl thiodipropionate and distearyl thiodipropionate;

  The amount of the heat stabilizer to be mixed is usually 100 ppm or more, preferably 200 ppm or more, and usually 5 parts by weight or less, preferably 1 part by weight or less, more preferably on a weight basis with respect to the biodegradable resin composition. Is 0.5 parts by weight or less. Below this range, the effect of the heat stabilizer tends to be small. On the other hand, if it exceeds this range, the manufacturing cost tends to be high, and the bleedout of the thermal stabilizer may occur.

  End-capping agents used mainly for the purpose of suppressing hydrolysis due to moisture in the atmosphere include carbodiimide compounds, epoxy compounds, oxazoline compounds, etc. Among the above carbodiimide compounds, as monocarbodiimide compounds, Examples include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide, and the like. Of these, dicyclohexylcarbodiimide and diisopropylcarbodiimide are preferred because they are easily available industrially.

Examples of the polycarbodiimide compound include U.S. Pat. No. 2,941,956, Japanese Patent Publication No. 47-33279, J. Pat. Org. Chem. 28, p2069-2075 (1963), and Chemical Review 1981, 81, No. 4, p. What was manufactured by the method described in 619-621 grade | etc., Can be used.
Examples of the organic diisocyanate that is a raw material for producing a polycarbodiimide compound include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and mixtures thereof. Specifically, 1,5-naphthalene diisocyanate, 4, 4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4- A mixture of tolylene diisocyanate and 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate , Dicyclohexylmethane-4,4′-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 2,6-diisopropylphenyl isocyanate, 1,3,5-triisopropylbenzene-2,4-diisocyanate, etc. it can.

Examples of the carbodiimidization catalyst used in the decarboxylation condensation reaction of organic diisocyanate include organophosphorus compounds and organometallic compounds represented by the general formula M (OR) n (where M is titanium,
Metal atoms such as sodium, potassium, vanadium, tungsten, hafnium, zirconium, lead, manganese, nickel, calcium and barium, R represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms , N represents a valence that the metal atom M can take). Among them, phospholene oxides are preferable for organic phosphorus compounds, and alcosides of titanium, hafnium, or zirconium are preferable for organometallic compounds.

  Specific examples of the phospholene oxides include 3-methyl-1-phenyl-2-phospholene-1-oxide, 3-methyl-1-ethyl-2-phospholene-1-oxide, and 1,3-dimethyl-2. -Phospholene-1-oxide, 1-phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 1-methyl-2-phospholene-1-oxide and their double bond isomers Can be illustrated. Of these, 3-methyl-1-phenyl-2-phospholene-1-oxide, which is easily available industrially, is particularly preferable.

  When synthesizing these polycarbodiimide compounds, a desired degree of polymerization can be controlled by using an active hydrogen-containing compound capable of reacting with monoisocyanate or other terminal isocyanate groups. Compounds used for such purposes include monoisocyanate compounds such as phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate, methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, Hydroxyl group-containing compounds such as polyethylene glycol monomethyl ether and polypropylene glycol monomethyl ether, amino group-containing compounds such as diethylamine, dicyclohexylamine, β-naphthylamine and cyclohexylamine, carboxyl group-containing compounds such as succinic acid, benzoic acid and cyclohexane acid, ethyl mercaptan , Mercapto group-containing compounds such as allyl mercaptan and thiophenol, And it can be exemplified various epoxy group-containing compound.

  These carbodiimide compounds may be used individually by 1 type, and 2 or more types may be mixed and used for them. In the present invention, it is particularly preferable to use a polycarbodiimide compound, and the degree of polymerization of the lower limit is 2 or more, preferably 4 or more, and the upper limit is usually 40 or less, preferably 20 or less. These carbodiimides are usually used in an amount of 0.1 to 5% by weight based on the entire resin composition.

In addition to these, known surface wettability improvers, flame retardants, mold release agents, incineration aids, pigments, dispersion aids, surfactants, hydrolysis inhibitors, end capping agents, crystal nucleating agents, compatibilizing agents, Etc. may be included.
Thus, the resin composition according to the present invention comprises the polyester resin (A), the polyester resin (B), the polyester resin (C), and the cellulose ester (D), and the polyester resin (A). The amount of the structural unit derived from succinic acid is within a predetermined range, and the blending ratio of the resins (A) to (C) is within a predetermined range. When a film is formed with the resin composition having such characteristics, the tear strength of the film is improved and the impact strength is excellent. By forming the film obtained from the resin composition according to the present invention into a bag, it is possible to obtain a bag that is less likely to tear due to tearing and less likely to tear due to impact. Alternatively, it is also preferable to use the resin composition according to the present invention as a multi-film material for agriculture.

2. Production Method of Resin Composition A known method can be applied as a production method of the resin composition according to the present invention. For example, blended polyester resin (A), polyester resin (B), raw material chips of polyester resin (C) and cellulose ester (D) are melt-mixed in the same extruder, each melted in a separate extruder The method of mixing later is mentioned. As the extruder, a single screw or a twin screw extruder can be used. Moreover, the cellulose ester (D) can also be added and mix | blended in the place which mixed and heat-melted polyester resin (A)-(C). At this time, blending oil or the like can be used for the purpose of uniformly dispersing other components. On the other hand, each raw material chip according to the polyester resins (A) to (C) is directly supplied to a molding machine to prepare a resin composition, and at the same time, a molded body such as a film can be obtained as it is.

3. Film The resin composition according to the present invention can be formed into a film by various molding methods applied to general-purpose plastics. With regard to the molding method, the effects of the present invention are particularly prominent when molded by extrusion molding or inflation molding. More specifically, for example, a method of cooling and solidifying a film, sheet or cylinder extruded to a predetermined thickness from a T die, I die or round die with a cooling roll, water, compressed air, etc. Is mentioned. Under the present circumstances, it is also possible to set it as the laminated | multilayer film which laminated | stacked several types of compositions in the range which does not inhibit the effect of this invention.

  The film-like molded product thus obtained may then be uniaxially or biaxially stretched by a roll method, a tenter method, a tubular method or the like. When extending | stretching, extending | stretching temperature is normally in the range of 30 to 110 degreeC, and a draw ratio is performed in the range of 0.6 to 10 times in the vertical and horizontal directions, respectively. Further, after stretching, heat treatment may be performed by a method of blowing hot air, a method of irradiating infrared rays, a method of irradiating microwaves, a method of contacting on a heat roll, or the like.

4). Multi film It is still more preferable when the resin composition according to the present invention is molded into a multi film for agriculture or the like. A known method as described above may be used for forming the multifilm. The multifilm obtained by molding the resin composition according to the present invention has the following effects. In the case of a multi-film, it can be said that a film excellent in tear strength is preferably used. In this respect, the multi-film obtained by molding the resin composition according to the present invention has improved tear strength and excellent impact strength. Therefore, in the laid multi film, it can suppress that a film tears and a defect part becomes large, and can also prevent that a multi film is torn by an impact. In addition, since the resin composition according to the present invention has components such as aliphatic polyester, aromatic aliphatic copolymer polyester, and aliphatic oxycarboxylic acid as main components, it is problematic even if it is embedded in the soil as it is after using a multi-film. There is no.

5. Bag The film obtained as described above may be formed into a bag. A known method can be applied for forming the bag. For example, it can be molded by heat-sealing the end of a blown tubular body. Here, as described above, the film constituting the bag has an improved impact strength and an improved impact strength. If the film is excellent in tear strength, it becomes possible to prevent the bag from tearing. In addition, since the impact strength is excellent, it is possible to prevent the bag from tearing when the bag is opened or when an object is packed in the bag.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In addition, the following examples are shown in order to explain the present invention in detail, and the present invention is not limited to the following examples unless it is contrary to the gist thereof.
The following resins and compounds used in the following examples and comparative examples were used.
<Aliphatic polyester resin>
・ Polybutylene succinate (hereinafter abbreviated as PBS) “GsPla (registered trademark) FZ91PN” manufactured by Mitsubishi Chemical Corporation
Polybutylene succinate adipate (hereinafter abbreviated as PBSA) “GsPla (registered trademark) FD92WN” manufactured by Mitsubishi Chemical Corporation
<Aromatic aliphatic copolymer polyester resin>
-Polybutylene adipate terephthalate (hereinafter abbreviated as PBAT) Ecoflex (registered trademark) manufactured by BASF Corp. * Melting point 120 ° C
<Polyester resin containing aliphatic oxycarboxylic acid>
・ Polylactic acid (hereinafter abbreviated as “PLA”) Ingeo2003D manufactured by Nature Works Japan Co., Ltd.
<Cellulose ester>
Cellulose acetate propionate (hereinafter abbreviated as “CAP”) EAST
CAP-482-20 Acetyl content 2.5%, Propylyl content 46.0%, Hydroxyl content 1.8%, number average molecular weight 75,000, manufactured by MAN
Cellulose acetate (hereinafter abbreviated as “CA”), Wako Pure Chemical Industries, Ltd., Acetyl content 38-40%

Production of Resin Composition [Examples 1-3, Comparative Examples 1-3]
PBS, PBSA, PBAT, PLA as the resin and CAP or CA as the cellulose ester in the ratio (parts by weight) shown in Table 1, respectively, twin screw extruder (TEX30α-59.5AW-15V, manufactured by Nippon Steel Works) /D=59.5), melt-kneaded using the twin-screw extruder, extruded into a strand from the exit of the extruder, cooled and solidified with water, and pelletized with a rotary cutter. The obtained pellets were dried at 70 ° C. for 6 hours under a nitrogen flow to obtain a resin composition. The set temperature during kneading was 190 ° C., and the screw rotation speed was 200 rpm.

In addition, when each resin was charged into the twin screw extruder, the moisture-proof bag enclosing each resin was opened and immediately charged into the twin screw extruder and melt-kneaded.
In Table 1, the “compound property” index is an index of ease of handling when compounding the resin composition in each of the examples and comparative examples, and the compound property “◯” indicates the resin composition. The compound can be kneaded without problems, and the compound property “Δ” is that the strand is not stable or the strand is not cut by a cutter.

Film forming and physical property evaluation [Examples 1 to 3, Comparative Examples 1 to 3]
Each resin composition obtained in the production of the above resin composition was molded at an molding temperature of 160 using an inflation molding machine (engineering plastic 30, die diameter: 75 mm, lip width: 0.8 mm) manufactured by Engineering Plastics Co., Ltd. A film having a temperature of 50 ° C., a blow ratio of 3.5 and a thickness of 50 μm was prepared. The moldability (bubble and frost state) was evaluated according to the following criteria with a discharge rate of 8 kg / h and constant air blow. The evaluation results of the film containing each resin composition based on the following evaluation criteria are shown in “Inflation moldability” in Table-1.

[Evaluation criteria for film moldability]
○: Low frost line and good moldability △: Slightly high frost line, but no problem with moldability ×: State where bubbles are not stable and cannot be molded (including foreign matter generation)
[Evaluation of film properties]
The following evaluation was implemented about each obtained in Examples 1-3 and Comparative Examples 1-3.

<Elastic modulus>
Based on JIS K7127 (1999), the elastic modulus of the film in the film flow direction (MD) during film formation was measured. The results are shown in the elastic modulus (MD) in Table-1.
<Stiffness when filmed>
In the above elastic modulus evaluation, the elastic modulus is 400 MPa or more, and the result is ○, 300 to 400 MPa is Δ, and 0 to 300 MPa is ×. The results are shown in “Stiffness when filmed” in Table 1.

<Elmendorf tear strength>
Based on JIS K7128-2 (1998), the tear strength in the film flow direction (MD) during film formation and in the direction perpendicular to the film flow direction (TD) was measured. The results are shown in “Tear (MD)” and “Tear (TD)” in Table 1, respectively.
<Punching impact strength>
Using a film impact tester manufactured by Toyo Seiki Co., Ltd., the punching impact strength of a film having a diameter of 50 mm was measured according to JIS P8134 (1998). Evaluation was performed by attaching a hemispherical metal jig having a diameter of 25.4 mm to the tip of the impact tester punched portion. The results are shown in Puncture in Table 1.

  From the results shown in Table 1, it is an aliphatic polyester-based resin containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, and contains 87 mol% or more of succinic acid units in all aliphatic dicarboxylic acid units. A polyester resin (A), an aliphatic aliphatic copolymer polyester resin containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit, wherein the aromatic dicarboxylic acid unit is included in all dicarboxylic acid units. By making the polyester resin (B) containing 5 mol% or more and 95 mol% or less, the polyester resin (C) containing an aliphatic oxycarboxylic acid, and the polyester resin composition containing a cellulose ester (D), compounding properties and It is clear that films with excellent inflation moldability and high tear strength and impact strength can be produced. Or it becomes.

Claims (5)

An aliphatic polyester-based resin containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit, the polyester resin containing 87 mol% or more of succinic acid units in the total aliphatic dicarboxylic acid units (A),
An aromatic aliphatic copolyester resin comprising an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit, wherein the aromatic dicarboxylic acid unit is contained in an amount of 5 mol% or more and 95 mol in all dicarboxylic acid units. % Or less of polyester resin (B), polyester resin containing aliphatic oxycarboxylic acid (C), and at least one cellulose ester selected from the group consisting of cellulose triacetate, cellulose acetate propionate and cellulose acetate butyrate ( A polyester resin composition containing D).   The resin composition according to claim 1, wherein the cellulose ester (D) is cellulose acetate propionate.   The film obtained by shape | molding the resin composition of Claim 1 or Claim 2.   The multifilm obtained by shape | molding the resin composition of Claim 1 or Claim 2.   The bag obtained by shape | molding the film of Claim 3.