Extruded film

Abstract

This extruded film contains a poly(3-hydroxyalkanoate)-based copolymer (A) and a poly(3-hydroxybutyrate) (B). The copolymer (A) preferably contains at least two types of poly(3-hydroxyalkanoate)-based copolymers having different constituent monomer types and / or constituent monomer content ratios. The copolymer (A) may include a copolymer (A-1) of a 3-hydroxybutyrate unit and another hydroxyalkanoate unit, wherein a content ratio of the other hydroxyalkanoate unit is 24 mol% or more.

Description

Extruded Film

[0001] The present invention relates to extruded films comprising poly(3-hydroxyalkanoate)-based resins.

[0002] In recent years, the separate collection and composting of food waste has been promoted, particularly in Europe, and there is a demand for plastic products that can be composted together with food waste. Furthermore, there are hopes for marine-degradable plastics to solve the problem of marine pollution caused by plastics.

[0003] As a material having such compost-degradability and marine-degradability, poly(3-hydroxyalkanoate) resins, typified by poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), have attracted attention.

[0004] The use of poly(3-hydroxyalkanoate) resins as resin materials for forming various molded articles has been investigated. For example, Patent Document 1 discloses an inflation film containing a poly(3-hydroxyalkanoate) resin as a main resin component.

[0005] Furthermore, Patent Document 2 discloses that a resin film is formed using two types of poly(3-hydroxyalkanoate) resins whose melting temperatures differ by 5°C or more, and that the film can be produced by extrusion molding using a T-die.

[0006] JP 2022-37396 A JP 2005-162884 A

[0007] According to the resin formulations described in Patent Documents 1 and 2, it is possible to produce extruded films containing poly(3-hydroxyalkanoate)-based resins. However, poly(3-hydroxyalkanoate)-based resins tend to solidify slowly after melting, which can result in insufficient productivity. It has been found that it tends to be difficult to increase the production speed, particularly when attempting to perform continuous extrusion molding using a T-die.

[0008] In extrusion molding using a T-die, a molten resin material is extruded from the T-die onto a casting roll and cooled while being molded into a film. In this process, if the production speed of film molding is increased, the resin material containing a poly(3-hydroxyalkanoate)-based resin tends to stick to the casting roll and become impossible to peel off.

[0009] In particular, in the examples described in Patent Document 1, pentaerythritol, which is known as a crystal nucleating agent for poly(3-hydroxyalkanoate)-based resins, is used. However, when a formulation not containing pentaerythritol is used, solidification becomes even slower, and the tendency for productivity to decrease becomes more pronounced.

[0010] Furthermore, when the resin formulation was changed to improve the solidification property of the poly(3-hydroxyalkanoate) resin, the stretchability was reduced, and the film broke in the subsequent stretching step, making it impossible to perform stretching. Therefore, it was difficult to achieve good stretchability while improving the productivity of film molding.

[0011] In view of the above-mentioned current situation, an object of the present invention is to provide an extruded film containing a poly(3-hydroxyalkanoate) resin that can be produced with good productivity.

[0012] As a result of intensive research aimed at solving the above problems, the present inventors discovered that by using a poly(3-hydroxyalkanoate) copolymer and a poly(3-hydroxybutyrate) resin in combination to form an extruded film, the resin raw material is less likely to stick to the casting roll, and the production speed of film molding can be significantly improved, which led to the completion of the present invention.

[0013] That is, the present invention relates to an extruded film containing a poly(3-hydroxyalkanoate) copolymer (A) and a poly(3-hydroxybutyrate) (B).

[0014] According to the present invention, it is possible to provide an extruded film containing a poly(3-hydroxyalkanoate)-based resin that can be produced with good productivity. According to the present invention, it is possible to continuously and productively produce an extruded film containing a poly(3-hydroxyalkanoate)-based resin that has good physical properties such as elongation and strength. According to a preferred embodiment of the present invention, the resin raw material is less likely to stick to a casting roll even without blending a sugar alcohol such as pentaerythritol, thereby significantly improving the production speed of film molding. Therefore, it is possible to avoid the problem of sugar alcohols bleeding out from the film and the problem of contamination of the production equipment (particularly the casting roll surface) due to bleed-out. According to a preferred embodiment of the present invention, it is possible to continuously produce an extruded film containing a poly(3-hydroxyalkanoate)-based resin at a high production speed by a molding method in which a molten resin raw material is extruded onto a casting roll through a T-die.

[0015] According to a preferred embodiment of the present invention, a poly(3-hydroxyalkanoate)-based resin-containing film that can achieve both high film molding productivity and good stretchability can be provided, and a poly(3-hydroxyalkanoate)-based resin-containing stretched film that has good physical properties such as elongation and strength can be continuously produced with high productivity. According to a preferred embodiment of the present invention, a poly(3-hydroxyalkanoate)-based resin-containing stretched film can be continuously produced at a high production rate by performing continuous stretching from a molding method in which a molten resin raw material is extruded from a T-die onto a cast roll.

[0016] Although the present invention will be described below by way of example, the present invention is not limited to the following example. The present example relates to an extruded film containing a poly(3-hydroxyalkanoate) copolymer (A) and a poly(3-hydroxybutyrate) (B).

[0017] [Poly(3-hydroxyalkanoate)-based copolymer (A)] The poly(3-hydroxyalkanoate)-based copolymer (A) may be a single poly(3-hydroxyalkanoate)-based copolymer or a mixture of two or more poly(3-hydroxyalkanoate)-based copolymers. However, since this makes it easier to achieve both good film productivity and good physical properties and also improves stretchability, it is preferable to include at least two types of poly(3-hydroxyalkanoate)-based copolymers that differ from each other in the types of constituent monomers and / or the content ratios of the constituent monomers.

[0018] The poly(3-hydroxyalkanoate) copolymer (A) is preferably a polymer having a 3-hydroxyalkanoate unit, specifically a polymer containing a unit represented by the following general formula (1): [—CHR—CH ２ -CO-O-] (1)

[0019] In the general formula (1), R is C ｐ H ２ｐ＋１ where p is an integer of 1 to 15. Examples of R include linear or branched alkyl groups such as methyl, ethyl, propyl, methylpropyl, butyl, isobutyl, t-butyl, pentyl, and hexyl. p is preferably an integer of 1 to 10, and more preferably an integer of 1 to 8.

[0020] As the poly(3-hydroxyalkanoate) copolymer (A), a poly(3-hydroxyalkanoate) copolymer produced by a microorganism is particularly preferred. In the poly(3-hydroxyalkanoate) copolymer produced by a microorganism, all of the 3-hydroxyalkanoate units are contained as (R)-3-hydroxyalkanoate units.

[0021] The poly(3-hydroxyalkanoate) copolymer (A) preferably contains 3-hydroxyalkanoate units (particularly units represented by general formula (1)) in an amount of 50 mol % or more, more preferably 60 mol % or more, and even more preferably 70 mol % or more of the total structural units. The poly(3-hydroxyalkanoate) copolymer (A) may contain only two or more types of 3-hydroxyalkanoate units as structural units of the polymer, or may contain other units (e.g., 4-hydroxyalkanoate units) in addition to one or more types of 3-hydroxyalkanoate units.

[0022] The poly(3-hydroxyalkanoate) copolymer (A) is preferably a copolymer of 3-hydroxybutyrate (hereinafter sometimes referred to as 3HB) units and other hydroxyalkanoate units (hereinafter also referred to as a "poly(3-hydroxybutyrate) copolymer"). In this copolymer, it is preferred that all of the 3-hydroxybutyrate units are (R)-3-hydroxybutyrate units.

[0023] Specific examples of poly(3-hydroxybutyrate) copolymers include poly(3-hydroxybutyrate-co-3-hydroxypropionate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (abbreviation: P3HB3HV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (abbreviation: P3HB3HH), poly(3-hydroxy Examples of suitable poly(3-hydroxybutyrate-co-3-hydroxyheptanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxynonanoate), poly(3-hydroxybutyrate-co-3-hydroxydecanoate), poly(3-hydroxybutyrate-co-3-hydroxyundecanoate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (abbreviation: P3HB4HB), etc. In particular, from the viewpoints of film productivity and mechanical properties, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) are preferred.

[0024] Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is particularly preferred from the viewpoints that by changing the composition ratio of the repeating units, it is possible to change the melting point and degree of crystallinity, and thereby change physical properties such as Young's modulus and heat resistance, making it possible to impart physical properties between those of polypropylene and polyethylene, and that it is easy to produce industrially and is a physically useful plastic. In particular, among poly(3-hydroxybutyrate)-based copolymers that tend to be thermally decomposed when heated to 180°C or higher, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is preferred from the viewpoints that it can lower the melting point and enable molding and processing at low temperatures.

[0025] Commercially available poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) products include Kaneka Biodegradable Polymer Green Planet (registered trademark) manufactured by Kaneka Corporation.

[0026] When the poly(3-hydroxyalkanoate) copolymer (A) is a poly(3-hydroxybutyrate) copolymer, the average content ratio of 3-hydroxybutyrate units and other hydroxyalkanoate units in all monomer units constituting the poly(3-hydroxyalkanoate) copolymer (A) is preferably 3-hydroxybutyrate units / other hydroxyalkanoates = 99 / 1 to 80 / 20 (mol % / mol %), more preferably 97 / 3 to 82 / 18 (mol % / mol %), and even more preferably 95 / 5 to 85 / 15 (mol % / mol %), from the viewpoint of achieving both the physical properties of the film and productivity.

[0027] The average content ratio of each monomer unit in all monomer units constituting the poly(3-hydroxyalkanoate) copolymer (A) can be determined by a method known to those skilled in the art, for example, the method described in paragraph

[0047] of WO 2013 / 147139. The average content ratio means the molar ratio of each monomer unit in all monomer units constituting the poly(3-hydroxyalkanoate) copolymer (A), and when the poly(3-hydroxyalkanoate) copolymer (A) is a mixture of two or more poly(3-hydroxyalkanoate) copolymers, it means the molar ratio of each monomer unit contained in the entire mixture.

[0028] As described above, the poly(3-hydroxyalkanoate) copolymer (A) preferably contains at least two types of poly(3-hydroxyalkanoate) copolymers that differ from each other in the types of constituent monomers and / or the content ratios of the constituent monomers. In this case, at least one type of highly crystalline poly(3-hydroxyalkanoate) copolymer and at least one type of low crystalline poly(3-hydroxyalkanoate) copolymer can be used in combination.

[0029] Generally, highly crystalline poly(3-hydroxyalkanoate) copolymers have excellent productivity but poor mechanical strength, while low-crystalline poly(3-hydroxyalkanoate) copolymers have poor productivity but excellent mechanical properties. By using both copolymers in combination, both productivity and physical properties of the film can be achieved. In addition, the stretchability of the film can also be improved.

[0030] The content of 3-hydroxybutyrate units in the highly crystalline poly(3-hydroxyalkanoate) copolymer is preferably higher than the average content of 3-hydroxybutyrate units in all monomer units constituting the poly(3-hydroxyalkanoate) copolymer (A). On the other hand, the content of 3-hydroxybutyrate units in the low-crystalline poly(3-hydroxyalkanoate) copolymer is preferably lower than the average content of 3-hydroxybutyrate units in all monomer units constituting the poly(3-hydroxyalkanoate) copolymer (A).

[0031] The method for obtaining a blend of two or more poly(3-hydroxyalkanoate) copolymers is not particularly limited, and may be a method for obtaining a blend by microbial production or a method for obtaining a blend by chemical synthesis. Alternatively, the blend may be obtained by melt-kneading two or more copolymers using an extruder, kneader, Banbury mixer, roll, or the like, or by dissolving two or more copolymers in a solvent, mixing, and drying the copolymers.

[0032] The weight average molecular weight of the entire poly(3-hydroxyalkanoate) copolymer (A) is not particularly limited, but from the viewpoint of achieving both the physical properties of the film and productivity, it is preferably from 200,000 to 2,000,000, more preferably from 300,000 to 1,500,000, and even more preferably from 400,000 to 1,000,000.

[0033] The weight-average molecular weight of the poly(3-hydroxyalkanoate) copolymer can be measured in terms of polystyrene using gel permeation chromatography (HPLC GPC system manufactured by Shimadzu Corporation) using a chloroform solution. A column suitable for measuring weight-average molecular weights can be used as the column for gel permeation chromatography. The weight-average molecular weights of the poly(3-hydroxyalkanoate) copolymers described below can also be measured in the same manner.

[0034] The method for producing the poly(3-hydroxyalkanoate) copolymer is not particularly limited, and may be a production method by chemical synthesis or a production method using a microorganism. Among these, a production method using a microorganism is preferred. Known methods can be applied to the production method using a microorganism. For example, known bacteria that produce copolymers of 3-hydroxybutyrate and other hydroxyalkanoates include Aeromonas caviae, which produces P3HB3HV and P3HB3HH, and Alcaligenes eutrophus, which produces P3HB4HB. In particular, with regard to P3HB3HH, in order to increase the productivity of P3HB3HH, Alcaligenes eutrophus AC32 strain (FERM BP-6038) (T. Fukui, Y. Doi, J. Bateriol., 179, pp. 4821-4830 (1997)) or the like into which genes encoding P3HA synthases have been introduced is more preferred, and microbial cells obtained by culturing these microorganisms under appropriate conditions and allowing P3HB3HH to accumulate within the cells are used. In addition to the above, genetically modified microorganisms into which various poly(3-hydroxyalkanoate) copolymer synthesis-related genes have been introduced may also be used depending on the poly(3-hydroxyalkanoate) copolymer to be produced, or the culture conditions, including the type of substrate, may be optimized.

[0035] As the poly(3-hydroxyalkanoate) copolymer (A), an unmodified poly(3-hydroxyalkanoate) copolymer can be used. However, a copolymer obtained by modifying an unmodified poly(3-hydroxyalkanoate) copolymer with a raw material that reacts with the copolymer, such as a peroxide (hereinafter referred to as a "modifying raw material"), may also be used. In the first and third embodiments described below, it is preferable to use an unmodified copolymer, and in the second embodiment, it is preferable to use a modified copolymer.

[0036] When the modified copolymer is used as a film raw material, the copolymer may be reacted with a modifying raw material in advance to form a modified copolymer into a film, or the modifying raw material may be mixed with the copolymer and reacted during film formation. When the copolymer is reacted with the modifying raw material, the entire copolymer may be reacted with the modifying raw material, or a part of the copolymer may be reacted with the modifying raw material to form a modified copolymer, and the remaining unmodified copolymer may then be added to the modified copolymer.

[0037] The modifying raw material is not particularly limited as long as it is a compound that can react with the poly(3-hydroxyalkanoate) copolymer, but organic peroxides are preferably used in terms of ease of handling and ease of control of the reaction with the poly(3-hydroxyalkanoate) copolymer. The compounds described below can be used as the organic compound.

[0038] Specific embodiments of the poly(3-hydroxyalkanoate) copolymer (A) are described below. (First Embodiment of Copolymer (A)) In the first embodiment, the poly(3-hydroxyalkanoate) copolymer (A) contains at least a copolymer (A-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 24 mol % or more. By using this copolymer (A-1), which has a high content of other hydroxyalkanoate units and exhibits low crystallinity, in combination with poly(3-hydroxybutyrate) (B), which will be described later, it is possible to efficiently produce a poly(3-hydroxyalkanoate)-containing extruded film having good film properties (especially elongation), such as elongation and strength.

[0039] In the first embodiment, the poly(3-hydroxyalkanoate) copolymer (A) preferably further contains, in addition to the copolymer (A-1), a copolymer (A-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 1 mol % or more and less than 5 mol %. By using the copolymer (A-2), which has higher crystallinity than the copolymer (A-1), in combination with the copolymer (A-1), it is possible to improve the balance between the productivity and physical properties of the film.

[0040] In copolymer (A-1), the content of other hydroxyalkanoate units is preferably 24 to 99 mol%, more preferably 24 to 50 mol%, even more preferably 24 to 35 mol%, and particularly preferably 24 to 30 mol%. In copolymer (A-2), the content of other hydroxyalkanoate units is preferably 2 to 4 mol%, more preferably 2 to 3 mol%.

[0041] As the copolymer (A-1) and the copolymer (A-2), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) is preferred, and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is particularly preferred.

[0042] The weight average molecular weight of each of the copolymers (A-1) and (A-2) is preferably from 200,000 to 2,500,000, more preferably from 220,000 to 2,300,000, and even more preferably from 250,000 to 2,000,000, from the viewpoint of achieving both the physical properties of the film and productivity.

[0043] In the first embodiment, the content of copolymer (A-1) is preferably 5% by weight or more and 85% by weight or less of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B) from the viewpoint of the balance between film productivity and physical properties and from the viewpoint of improving film elongation. The lower limit is more preferably 15% by weight or more, even more preferably 20% by weight or more, and particularly preferably 25% by weight or more from the viewpoint of elongation. The upper limit is more preferably 70% by weight or less, even more preferably 60% by weight or less, even more preferably 50% by weight or less, and particularly preferably 40% by weight or less from the viewpoint of film productivity.

[0044] When the copolymer (A) contains the copolymer (A-1) and the copolymer (A-2), the weight ratio (A-1 / A-2) of the copolymer (A-1) to the copolymer (A-2) is preferably 20 / 80 to 80 / 20, more preferably 30 / 70 to 70 / 30, and even more preferably 40 / 60 to 60 / 40, from the viewpoint of achieving both the physical properties of the film and productivity and improving the elongation of the film.

[0045] In the first embodiment, the poly(3-hydroxyalkanoate) copolymer (A) preferably further contains, in addition to copolymer (A-1) and copolymer (A-2), a copolymer (A-3) of 3-hydroxybutyrate units and other hydroxyalkanoate units, in which the content of other hydroxyalkanoate units is 5 mol % or more but less than 24 mol %. The crystallinity of copolymer (A-3) is intermediate between that of copolymer (A-1) and copolymer (A-2). The combined use of such copolymer (A-3) can improve the balance between film productivity and physical properties.

[0046] In the copolymer (A-3), the content of the other hydroxyalkanoate units is preferably 6 mol% or more, more preferably 20 mol% or less, even more preferably 15 mol% or less, and particularly preferably 10 mol% or less.

[0047] As the copolymer (A-3), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) is preferred, with poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) being particularly preferred.

[0048] The weight average molecular weight of the copolymer (A-3) is preferably from 200,000 to 2,500,000, more preferably from 250,000 to 2,300,000, and even more preferably from 300,000 to 2,000,000, from the viewpoint of achieving both the physical properties of the film and productivity.

[0049] The content of copolymer (A-3) is preferably 0% by weight or more and 50% by weight or less of the total weight of poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B), from the viewpoint of achieving both the physical properties of the film and productivity. The lower limit is preferably 10% by weight or more, more preferably 20% by weight or more. The upper limit is more preferably 45% by weight or less, even more preferably 40% by weight or less.

[0050] In the first embodiment, the weight average molecular weight of the entire poly(3-hydroxyalkanoate) copolymer (A) is not particularly limited, but from the viewpoint of achieving both the physical properties of the film and productivity, it is preferably from 200,000 to 2,000,000, more preferably from 300,000 to 1,500,000, and even more preferably from 400,000 to 1,000,000.

[0051] (Second Aspect of Copolymer (A)) In the second aspect, the poly(3-hydroxyalkanoate) copolymer (A) contains a reaction product (A') of a poly(3-hydroxyalkanoate) copolymer with an organic peroxide. The reaction product is a modified resin in which a crosslinked structure has been introduced into the poly(3-hydroxyalkanoate) copolymer by reaction with an organic peroxide. By using the poly(3-hydroxyalkanoate) copolymer having a crosslinked structure in combination with poly(3-hydroxybutyrate) (B), it is possible to achieve both high productivity and stretchability of the poly(3-hydroxyalkanoate) resin-containing extruded film.

[0052] The poly(3-hydroxyalkanoate) copolymer before being reacted with the organic peroxide may be a single poly(3-hydroxyalkanoate) copolymer or a mixture of two or more poly(3-hydroxyalkanoate) copolymers. However, in order to achieve both film productivity and stretchability and to facilitate the achievement of good film properties (elongation, strength, etc.), it is preferable to contain at least two types of poly(3-hydroxyalkanoate) copolymers that differ from each other in the type of constituent monomer and / or the content ratio of the constituent monomer.

[0053] In the second embodiment, the reaction product (A') preferably contains at least a reaction product of an organic peroxide and a copolymer (A-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the copolymer (A-1) having a high content of other hydroxyalkanoate units and exhibiting low crystallinity, and by reacting the copolymer (A-1) with an organic peroxide and using the copolymer (A-1) in combination with poly(3-hydroxybutyrate) (B), the productivity and stretchability of the poly(3-hydroxyalkanoate)-based resin-containing extruded film can be improved in a well-balanced manner, and good film properties can be easily achieved.

[0054] In the second embodiment, the poly(3-hydroxyalkanoate) copolymer (A) preferably contains a copolymer (A-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 1 mol % or more and less than 5 mol %. The copolymer (A-2) may be a reaction product (A') with an organic peroxide or an unreacted product, but the reaction product (A') is preferred. By using the copolymer (A-2), which has higher crystallinity than the copolymer (A-1), a well-balanced improvement in film productivity and stretchability is achieved, and good film physical properties are easily achieved. In particular, the copolymer (A-2) is preferably used in combination with the copolymer (A-1).

[0055] In copolymer (A-1), the content of other hydroxyalkanoate units is preferably 24 to 99 mol%, more preferably 24 to 50 mol%, even more preferably 24 to 35 mol%, and particularly preferably 24 to 30 mol%. In copolymer (A-2), the content of other hydroxyalkanoate units is preferably 2 to 4 mol%, more preferably 2 to 3 mol%.

[0056] As the copolymer (A-1) and the copolymer (A-2), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) is preferred, and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is particularly preferred.

[0057] The weight average molecular weight of the copolymer (A-1) and the copolymer (A-2) is preferably from 200,000 to 2,300,000, more preferably from 220,000 to 2,000,000, and even more preferably from 250,000 to 1,500,000, from the viewpoint of achieving both film productivity and stretchability.

[0058] In the second embodiment, the amount of copolymer (A-1) used is preferably 5% by weight or more and 60% by weight or less, based on the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B), from the viewpoint of the balance between film productivity and stretchability, and from the viewpoint of improving film elongation. The lower limit is more preferably 7% by weight or more, even more preferably 10% by weight or more, and particularly preferably 20% by weight or more, from the viewpoint of film elongation. The upper limit is more preferably 50% by weight or less, even more preferably 40% by weight or less, from the viewpoint of film productivity.

[0059] When the film contains the copolymer (A-1) and the copolymer (A-2), the weight ratio (A-1 / A-2) of the copolymer (A-1) to the copolymer (A-2) is preferably 20 / 80 to 80 / 20, more preferably 30 / 70 to 70 / 30, and even more preferably 40 / 60 to 60 / 40, from the viewpoint of achieving both the productivity and the stretchability of the film and improving the elongation of the film.

[0060] In the second embodiment, the poly(3-hydroxyalkanoate) copolymer (A) preferably contains a copolymer (A-3) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 5 mol% or more but less than 24 mol%. The copolymer (A-3) may be a reaction product (A') with an organic peroxide or an unreacted product, but the reaction product (A') is preferred. The crystallinity of the copolymer (A-3) is intermediate between that of the copolymer (A-1) and the copolymer (A-2). The use of such a copolymer (A-3) improves the balance between film productivity and stretchability, and further facilitates the achievement of good film physical properties. In particular, it is preferred to use the copolymer (A-3) in combination with the copolymer (A-1) and / or the copolymer (A-2).

[0061] In the copolymer (A-3), the content of the other hydroxyalkanoate units is preferably 6 mol% or more, more preferably 20 mol% or less, even more preferably 15 mol% or less, and particularly preferably 10 mol% or less.

[0062] As the copolymer (A-3), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) is preferred, with poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) being particularly preferred.

[0063] The weight average molecular weight of the copolymer (A-3) is preferably from 200,000 to 2,500,000, more preferably from 250,000 to 2,300,000, and even more preferably from 300,000 to 2,000,000, from the viewpoint of achieving both film productivity and stretchability.

[0064] The content of copolymer (A-3) is preferably 0% by weight or more and 85% by weight or less of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B), from the viewpoint of achieving both film productivity and stretchability, and from the viewpoint of film physical properties. The lower limit is preferably 5% by weight or more, more preferably 10% by weight or more, even more preferably 20% by weight or more, even more preferably 30% by weight or more, and particularly preferably 40% by weight or more. The upper limit is more preferably 80% by weight or less, and even more preferably 75% by weight or less.

[0065] In the second embodiment, the weight-average molecular weight of the entire poly(3-hydroxyalkanoate) copolymer (A) is not particularly limited, but from the viewpoint of achieving both film productivity and stretchability, it is preferably 200,000 to 2,000,000, more preferably 300,000 to 1,500,000, and even more preferably 400,000 to 1,000,000. However, the weight-average molecular weight described here is a value measured for the copolymer before it is reacted with the organic peroxide.

[0066] [Organic Peroxide] By reacting a poly(3-hydroxyalkanoate) copolymer with an organic peroxide to introduce a crosslinked structure, the film becomes less likely to break even when stretched, making it possible to form a film with good stretchability.

[0067] The organic peroxide is not particularly limited, and examples thereof include diisobutyl peroxide, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, bis(4-t-butylcyclohexyl)peroxydicarbonate, bis(2-ethylhexyl)peroxydicarbonate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di(3,5,5-trimethylhexanoyl)peroxide, dilauroyl peroxide, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, bis(4-t-butylcyclohexyl)peroxydicarbonate, bis(2-ethylhexyl)peroxydicarbonate, t-hexyl ... Examples of peroxyalkylene oxides include 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoyl peroxide, t-butylperoxy 2-ethylhexyl carbonate, t-butylperoxy isopropyl carbonate, 1,6-bis(t-butylperoxycarbonyloxy)hexane, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy acetate, t-butylperoxybenzoate, t-amylperoxy, 3,5,5-trimethylhexanoate, 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane, and 2,2-di-t-butylperoxybutane. Among these, dibenzoyl peroxide, t-butylperoxy 2-ethylhexyl carbonate, and t-butylperoxy isopropyl carbonate are preferred. One organic peroxide may be used alone, or two or more organic peroxides may be used in combination.

[0068] The organic peroxide may be used in various forms such as solid or liquid, and may be in liquid form diluted with a diluent, etc. Among these, an organic peroxide in a form that can be mixed with a poly(3-hydroxyalkanoate)-based copolymer (particularly an organic peroxide that is liquid at room temperature (25°C)) is preferred because it can be uniformly dispersed in the poly(3-hydroxyalkanoate)-based copolymer and makes it easier to suppress local modification reactions.

[0069] From the viewpoint of improving the stretchability of the film, the amount of organic peroxide used is preferably 0.01 to 3 parts by weight, more preferably 0.03 to 2 parts by weight, even more preferably 0.05 to 1 part by weight, and particularly preferably 0.1 to 0.5 parts by weight, per 100 parts by weight of the poly(3-hydroxyalkanoate) copolymer to be reacted with the organic peroxide.

[0070] The reaction product (A') of a poly(3-hydroxyalkanoate) copolymer and an organic peroxide can be preferably obtained by feeding the poly(3-hydroxyalkanoate) copolymer and the organic peroxide into an extruder and melt-kneading them. This allows the poly(3-hydroxyalkanoate) copolymer to be uniformly crosslinked. Furthermore, in addition to the poly(3-hydroxyalkanoate) copolymer and the organic peroxide, other components such as a crystal nucleating agent and a lubricant, as described below, may also be fed into the extruder and melt-kneaded. Furthermore, poly(3-hydroxybutyrate) (B) may also be fed into the extruder and melt-kneaded.

[0071] The melt-kneading can be carried out according to a known or conventional method, and can be carried out using, for example, an extruder (single-screw extruder or twin-screw extruder), a kneader, or the like. The conditions for melt-kneading are not particularly limited and can be set appropriately, but it is preferable to set a resin temperature and residence time that can complete the reaction with the organic peroxide during melt-kneading. Specifically, it is preferable to melt-knead at a resin temperature measured with a die thermometer in the range of 130°C to 190°C. It is also preferable to melt-knead so that the residence time in the extruder is 60 seconds to 300 seconds.

[0072] After melt-kneading, the resin material can be extruded into strands and cut to obtain pellets having particle shapes such as cylindrical, elliptical, spherical, cubic, and rectangular parallelepiped shapes. The produced pellets are preferably used after being thoroughly dried at 40 to 80°C to remove moisture. However, the pelletizing step may be omitted, and the film forming step may be carried out immediately after the melt-kneading step.

[0073] (Third Aspect of Copolymer (A)) In the third aspect, the poly(3-hydroxyalkanoate)-based copolymer (A) contains a copolymer (A-3') of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of the other hydroxyalkanoate units being 5 mol% or more and less than 24 mol% and having a weight-average molecular weight of 700,000 or more. By using the copolymer (A-3') having a medium degree of crystallinity and a high molecular weight in combination with the poly(3-hydroxybutyrate) (B), the stretchability of the poly(3-hydroxyalkanoate)-based resin-containing extruded film can be improved.

[0074] In the copolymer (A-3′), the content of the other hydroxyalkanoate units is 5 mol % or more and less than 24 mol %, with the lower limit being preferably 6 mol % or more, more preferably 8 mol % or more, and even more preferably 10 mol % or more, and the upper limit being preferably 20 mol % or less, more preferably 17 mol % or less, and even more preferably 14 mol % or less.

[0075] The copolymer (A-3') is preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate), with poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) being particularly preferred.

[0076] The weight average molecular weight of the copolymer (A-3') is 700,000 or more, preferably 750,000 or more. The upper limit is not particularly limited, but from the viewpoint of productivity, it is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less.

[0077] In the third embodiment, the content of the copolymer (A-3′) is 20% by weight or more and 80% by weight or less of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and the poly(3-hydroxybutyrate) (B) from the viewpoint of the balance between the stretchability of the film, productivity, and strength. This allows the effect of improving stretchability by incorporating the copolymer (A-3′) to be obtained, and also allows the extruded film to be produced with good productivity. From the viewpoint of the stretchability of the film, the lower limit is preferably 30% by weight or more, more preferably 40% by weight or more, even more preferably 45% by weight or more, even more preferably 50% by weight or more, particularly preferably 60% by weight or more, and most preferably 70% by weight or more. From the viewpoint of the productivity and stretchability of the film, the upper limit is preferably 75% by weight or less, more preferably 70% by weight or less.

[0078] From the viewpoint of stretchability, copolymer (A-3') preferably comprises a copolymer (A-3'-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 5 mol% or more but less than 10 mol% and the weight-average molecular weight is 700,000 or more, and a copolymer (A-3'-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 10 mol% or more but less than 24 mol% and the weight-average molecular weight is 700,000 or more. In this case, from the viewpoint of stretchability, the proportion of copolymer (A-3'-2) relative to the total of copolymer (A-3'-1) and copolymer (A-3'-2) is preferably 30 to 90 wt%, more preferably 50 to 85 wt%, and even more preferably 60 to 83 wt%.

[0079] In a third embodiment, the poly(3-hydroxyalkanoate) copolymer (A) may further contain a copolymer (A-3″) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 5 mol % or more and less than 24 mol % and the weight average molecular weight is less than 700,000.

[0080] In the copolymer (A-3"), the content of the other hydroxyalkanoate units is 5 mol% or more and less than 24 mol%, with the lower limit being preferably 6 mol% or more, more preferably 8 mol% or more, and even more preferably 10 mol% or more. The upper limit is preferably 20 mol% or less, more preferably 17 mol% or less, and even more preferably 14 mol% or less.

[0081] As the copolymer (A-3"), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) is preferred, and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is particularly preferred.

[0082] The weight average molecular weight of the copolymer (A-3″) is less than 700,000, and from the viewpoint of film productivity, it is preferably 600,000 or less, and more preferably 500,000 or less. The lower limit is not particularly limited, but from the viewpoint of the physical properties of the film, it is preferably 200,000 or more, and more preferably 300,000 or more.

[0083] The copolymer (A) may be composed solely of the copolymer (A-3'), or may be composed solely of the copolymer (A-3') and the copolymer (A-3"), but may further contain a poly(3-hydroxyalkanoate) copolymer that does not fall into either the copolymer (A-3') or the copolymer (A-3"). Examples of such poly(3-hydroxyalkanoate) copolymers include a copolymer (A-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, in which the content of the other hydroxyalkanoate units is 1 mol % or more and less than 5 mol %, and a copolymer (A-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, in which the content of the other hydroxyalkanoate units is 24 mol % or more.

[0084] The amount of copolymer (A-3') relative to the total amount of copolymer (A), or when copolymer (A-3") is contained, the total amount of copolymer (A-3') and copolymer (A-3") relative to the total amount of copolymer (A), is, for example, preferably 70 to 100% by weight, more preferably 80 to 100% by weight, and even more preferably 90 to 100% by weight.

[0085] In the third embodiment, the weight average molecular weight of the entire poly(3-hydroxyalkanoate) copolymer (A) is not particularly limited, but from the viewpoint of the stretchability of the film, it is preferably 500,000 to 2,000,000, more preferably 600,000 to 1,500,000, and even more preferably 700,000 to 1,000,000.

[0086] [Poly(3-hydroxybutyrate) (B)] The extruded film according to this embodiment contains poly(3-hydroxybutyrate) (B). Poly(3-hydroxybutyrate) (B) exhibits higher crystallinity than the poly(3-hydroxyalkanoate)-based copolymer (A) and has the property of being easily solidified. Therefore, by incorporating this resin into the composition, the solidification of poly(3-hydroxybutyrate) (B) proceeds rapidly when the molten resin material is cooled on a cast roll, making it difficult for the entire resin material to stick to the cast roll, thereby increasing the productivity of extruded films containing poly(3-hydroxyalkanoate)-based resins.

[0087] The poly(3-hydroxybutyrate) (B) refers to a homopolymer of 3-hydroxybutyrate or a polymer containing, in addition to 3-hydroxybutyrate units, a small amount of hydroxyalkanoate units other than 3-hydroxybutyrate units. Specifically, the poly(3-hydroxybutyrate) (B) preferably contains 3-hydroxybutyrate units in a proportion of more than 99 mol % and not more than 100 mol % of all of its constituent monomers.

[0088] The hydroxyalkanoate unit other than the 3-hydroxybutyrate unit that can be contained in the poly(3-hydroxybutyrate) (B) is not particularly limited as long as it is copolymerizable with the 3-hydroxybutyrate unit, and examples thereof include a 3-hydroxyalkanoate unit other than the 3-hydroxybutyrate unit and a hydroxyalkanoate unit other than the 3-hydroxyalkanoate unit (for example, a 4-hydroxyalkanoate unit). In particular, a 3-hydroxyhexanoate unit is preferred.

[0089] The weight-average molecular weight of poly(3-hydroxybutyrate) (B) is not particularly limited, but from the viewpoint of improving film productivity, it is preferably 200,000 to 2,000,000, and more preferably 300,000 to 1,500,000. The upper limit is more preferably 1,000,000 or less, and particularly preferably 500,000 or less. The weight-average molecular weight can be measured by the method described above.

[0090] The poly(3-hydroxybutyrate) (B) may be an unmodified resin, or may be a resin modified by reaction with an organic peroxide. The type and amount of organic peroxide that can be used and the modification method are the same as those described above for the poly(3-hydroxyalkanoate) copolymer (A) of the second embodiment, and therefore further description thereof will be omitted.

[0091] When the extruded film according to the present embodiment contains modified poly(3-hydroxybutyrate) (B), the modification of the poly(3-hydroxyalkanoate)-based copolymer (A) and the modification of the poly(3-hydroxybutyrate) (B) may be carried out separately and then the two may be mixed together, or the poly(3-hydroxyalkanoate)-based copolymer (A) and the poly(3-hydroxybutyrate) (B) may be mixed together before modification, and then both may be modified simultaneously.

[0092] In the extruded film according to this embodiment, the content of poly(3-hydroxybutyrate) (B) is preferably 2% by weight or more and 75% by weight or less of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B) from the viewpoint of achieving both film productivity and physical properties. The lower limit is more preferably 3% by weight or more, even more preferably 10% by weight or more, and particularly preferably 15% by weight or more from the viewpoint of improving productivity. The upper limit is more preferably 70% by weight or less, even more preferably 60% by weight or less, even more preferably 50% by weight or less, particularly preferably 40% by weight or less, and most preferably 30% by weight or less from the viewpoint of film physical properties.

[0093] In particular, in the second and third embodiments, the content of poly(3-hydroxybutyrate) (B) is preferably 5% by weight or more and 60% by weight or less of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B) from the viewpoint of achieving both film productivity and stretchability. The lower limit is more preferably 10% by weight or more, and even more preferably 12% by weight or more, from the viewpoint of improving film productivity. The upper limit is more preferably 50% by weight or less, even more preferably 40% by weight or less, even more preferably 30% by weight or less, particularly preferably 25% by weight or less, and most preferably 20% by weight or less, from the viewpoint of film physical properties.

[0094] The extruded film according to this embodiment is a resin film mainly composed of poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B). The total proportion of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B) in the total amount of the extruded film may be 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, and even more preferably 90% by weight or more. It may also be 95% by weight or more, or 98% by weight or more.

[0095] (Other Resins) The extruded film according to this embodiment may contain other resins in addition to the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B), provided that the effects of the invention are not impaired. Examples of such other resins include aliphatic polyester resins such as polylactic acid, polybutylene succinate adipate, polybutylene succinate, and polycaprolactone, and aliphatic aromatic polyester resins such as polybutylene adipate terephthalate, polybutylene sebate terephthalate, and polybutylene azelate terephthalate. Only one type of other resin may be contained, or two or more types may be contained.

[0096] The content of the other resin is not particularly limited, but is preferably 100 parts by weight or less, more preferably 50 parts by weight or less, and even more preferably 30 parts by weight or less, relative to 100 parts by weight of the total of the poly(3-hydroxyalkanoate) copolymer (A) and the poly(3-hydroxybutyrate) (B). It may be 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less. The lower limit of the content of the other resin is not particularly limited, and may be 0 parts by weight or more.

[0097] The extruded film according to this embodiment may contain additives that can be used together with the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B), provided that the effects of the invention are not impaired. Examples of such additives include colorants such as pigments and dyes, odor absorbers such as activated carbon and zeolite, fragrances such as vanillin and dextrin, fillers, plasticizers, antioxidants, weather resistance improvers, UV absorbers, crystal nucleating agents, lubricants, release agents, water repellents, antibacterial agents, and sliding properties improvers. Only one type of additive may be contained, or two or more types may be contained. The content of these additives can be appropriately determined by those skilled in the art depending on the intended use. Crystal nucleating agents, lubricants, fillers, and plasticizers are described in more detail below.

[0098] (Crystal Nucleating Agent) The extruded film according to this embodiment may contain a crystal nucleating agent. Examples of crystal nucleating agents include sugar alcohols such as pentaerythritol, galactitol, and mannitol; talc; fatty acid amides; orotic acid, aspartame, cyanuric acid, glycine, zinc phenylphosphonate, and boron nitride. Among these, sugar alcohols are preferred, and pentaerythritol is particularly preferred, because they are particularly effective in promoting the crystallization of the poly(3-hydroxyalkanoate) copolymer (A) and the poly(3-hydroxybutyrate) (B). One type of crystal nucleating agent may be used, or two or more types may be used, and the ratio of use can be appropriately adjusted depending on the purpose.

[0099] When a nucleating agent is used, the amount thereof is not particularly limited, but is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, and even more preferably 0.7 to 1.5 parts by weight, per 100 parts by weight of the total of the poly(3-hydroxyalkanoate) copolymer (A) and the poly(3-hydroxybutyrate) (B).

[0100] However, the extruded film according to this embodiment may be substantially free of sugar alcohols such as pentaerythritol. "Substantially free of sugar alcohols" means that the amount of sugar alcohols added is less than 0.1 parts by weight per 100 parts by weight of the total of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B). It may also be less than 0.01 parts by weight. In an embodiment in which sugar alcohols are not added substantially, the problem of sugar alcohols bleeding out from the film and the resulting contamination of the cast roll surface can be avoided.

[0101] When sugar alcohols are not substantially blended, it is preferable to blend talc and / or a fatty acid amide as a crystal nucleating agent, and it is particularly preferable to blend both talc and a fatty acid amide. By using these crystal nucleating agents in combination with poly(3-hydroxybutyrate) (B), even when sugar alcohols are not substantially blended, it is possible to improve the productivity of the extruded film and further to suppress the problem of blocking, in which films stick to each other after being wound up. Specific examples of fatty acid amides are as described in detail below as lubricants. The fatty acid amide blended in the extruded film according to this embodiment can function as both a crystal nucleating agent and a lubricant.

[0102] (Lubricant) The extruded film according to this embodiment may contain a lubricant. Examples of lubricants include behenamide, oleamide, erucamide, stearamide, palmitamide, N-stearylbehenamide, N-stearylerucamide, ethylenebisstearamide, ethylenebisoleamide, ethylenebiserucamide, ethylenebislauricamide, ethylenebiscapricamide, p-phenylenebisstearamide, and polycondensates of ethylenediamine, stearic acid, and sebacic acid. Among these, behenamide or erucamide is preferred because of its particularly excellent lubricating effect on the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B). One or more lubricants may be used, and the ratio of their use can be adjusted appropriately depending on the purpose.

[0103] When a lubricant is used, the amount thereof is not particularly limited, but is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, and even more preferably 0.1 to 1.5 parts by weight, per 100 parts by weight of the total of the poly(3-hydroxyalkanoate) copolymer (A) and the poly(3-hydroxybutyrate) (B). The extruded film according to this embodiment preferably contains a lubricant, but does not necessarily contain one.

[0104] (Filler) The extruded film according to this embodiment may contain a filler. By including a filler, the film can have higher strength. The filler may be either an inorganic filler or an organic filler, or both may be used in combination. The inorganic filler is not particularly limited, but examples thereof include talc, silicates, carbonates, sulfates, phosphates, oxides, hydroxides, nitrides, and carbon black. Only one type of inorganic filler may be used, or two or more types may be used in combination.

[0105] When the filler is used, its content is not particularly limited, but is preferably 0.5 to 100 parts by weight, more preferably 1 to 80 parts by weight, even more preferably 3 to 70 parts by weight, and even more preferably 5 to 60 parts by weight, per 100 parts by weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B). However, the extruded film according to this embodiment may be substantially free of a filler. "Substantially no filler" means that the amount of filler is less than 0.5 parts by weight, per 100 parts by weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B). It may also be less than 0.1 parts by weight.

[0106] (Plasticizer) The extruded film according to this embodiment may contain a plasticizer. Examples of plasticizers include glycerin ester compounds, citrate ester compounds, sebacate compounds, adipate compounds, polyether ester compounds, benzoate ester compounds, phthalate ester compounds, isosorbide ester compounds, polycaprolactone compounds, and dibasic acid ester compounds. Among these, glycerin ester compounds, citrate ester compounds, sebacate ester compounds, and dibasic acid ester compounds are preferred because of their particularly excellent plasticizing effect on the poly(3-hydroxyalkanoate) copolymer (A). Examples of glycerin ester compounds include glycerin diacetomonolaurate. Examples of citrate ester compounds include acetyl tributyl citrate. Examples of sebacate ester compounds include dibutyl sebacate. Examples of dibasic acid ester compounds include benzyl methyl diethylene glycol adipate. One type of plasticizer may be used, or two or more types may be used, and the ratio of use can be adjusted appropriately depending on the purpose.

[0107] When a plasticizer is used, the amount used is not particularly limited, but is preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, and even more preferably 3 to 10 parts by weight, per 100 parts by weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B). However, the extruded film according to this embodiment may be substantially free of plasticizer. "Substantially free of plasticizer" means that the amount of plasticizer is less than 1 part by weight per 100 parts by weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B). It may also be less than 0.1 part by weight.

[0108] [Extruded Film] In this specification, the term "extruded film" refers to a film produced by an extrusion molding method. The extruded film according to this embodiment may be an unstretched film that has not been subjected to a stretching process, or a stretched film that has been stretched in the MD and / or TD directions after film formation. The term "extruded film" as used herein may include both an unstretched film and a stretched film. From the viewpoint of strength, a stretched film is preferred. In particular, according to the second and third aspects, stretched films can be produced with high productivity.

[0109] The thickness of the extruded film according to this embodiment is preferably 10 to 200 μm, more preferably 15 to 150 μm, and even more preferably 20 to 100 μm, from the viewpoints of uniform thickness, appearance, strength, lightness, etc. of the film.

[0110] The extruded film according to this embodiment is preferably a long film produced industrially, and more preferably a strip-shaped film wound into a roll. The length of such a film is not particularly limited, but may be, for example, 5,000 m or more, or 10,000 m or more. In this embodiment, such a long film can be produced continuously and stably.

[0111] [Method for Producing Extruded Film] Next, an example of a method for producing an extruded film according to this embodiment will be described, but the present invention is not limited to the following description. An extruded film is produced by melting a film raw material containing poly(3-hydroxyalkanoate) copolymer (A), poly(3-hydroxybutyrate) (B), and, if necessary, other components, and extruding the molten film raw material, i.e., by performing an extrusion molding method. The extrusion molding method makes it possible to easily and continuously produce a film with a uniform thickness. In extrusion molding, a single-screw extruder, a twin-screw extruder, or the like can be used as appropriate.

[0112] Examples of extrusion molding methods include the T-die method, in which a molten raw material is extruded through a T-die into a flat film, and the inflation method, in which a molten resin is extruded through a ring-shaped die and gas is blown into the extrusion to expand it into a bag-like shape. In particular, a film produced by extrusion molding through a T-die is called a T-die film. The present invention can be suitably applied to the production of T-die films. The production of T-die films will be described in detail below.

[0113] The conditions for melting the film raw materials may be any conditions under which the poly(3-hydroxyalkanoate) copolymer (A) and the poly(3-hydroxybutyrate) (B) melt, and the temperature of the molten film raw materials may be, for example, about 140 to 210°C.

[0114] The molten film material is then extruded onto a casting roll to form a film. The molten film material comes into contact with the casting roll and moves along the surface of the casting roll, where it cools and solidifies.

[0115] This step may involve extruding the melt onto one or more casting rolls, or may involve placing a touch roll opposite the casting roll and sandwiching the melt extruded onto the casting roll between the touch rolls. An air knife or air chamber may be used to ensure stable contact of the melt with the casting roll. To efficiently cool the side opposite the contact surface with the casting roll, the casting roll may be placed in a water tank or an air chamber may be used.

[0116] The lower limit of the set temperature of the casting roll is preferably 0° C. or higher, more preferably 10° C. or higher, and even more preferably 15° C. or higher, in order to suppress the tackiness of the poly(3-hydroxyalkanoate) copolymer (A) and improve its releasability from the casting roll. In addition, the temperature is preferably a temperature exceeding the glass transition temperature (Tg) of the poly(3-hydroxyalkanoate) copolymer (A) + 10° C.

[0117] The upper limit of the temperature setting of the cast roll is not particularly limited, but from the viewpoint of promoting solidification of the poly(3-hydroxyalkanoate) copolymer (A), it is preferably 80°C or less, more preferably 60°C or less.

[0118] Next, the film cooled on the casting roll is transported while the casting roll is rotated, and the film is peeled off from the casting roll, thereby obtaining an unstretched film.

[0119] The resulting film is then stretched in the MD direction to obtain a uniaxially stretched film with high strength in the MD direction. The MD direction is also called the machine direction, flow direction, or longitudinal direction. The TD direction, which will be described later, is the direction perpendicular to the MD direction and is also called the perpendicular direction or width direction.

[0120] The stretching step in the MD direction can be carried out continuously in one production line from the time of peeling from the casting roll. This step is not particularly limited, but can be carried out, for example, by using a roll longitudinal stretching machine and varying the rotation speed of multiple rolls that transport the film.

[0121] To perform stretching, it is desirable to soften the film material to a degree that makes stretching possible. Therefore, it is desirable to perform stretching in the MD direction while heating the film to a temperature close to the melting point of the poly(3-hydroxyalkanoate)-based resin. Specifically, the heating temperature is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher. When a reaction product (A') with an organic peroxide or a high molecular weight substance (A-3') is used as the poly(3-hydroxyalkanoate)-based copolymer, the film is less likely to break even when stretched at such high temperatures, and stretching at a high magnification is possible. The upper limit of the heating temperature is preferably below the melting point of the poly(3-hydroxyalkanoate)-based resin.

[0122] The heating method is not particularly limited, but examples thereof include a method of exposing the film to an air current adjusted to a predetermined temperature, a method of controlling the film temperature by setting a roll to a predetermined temperature, a method of heating the film using an auxiliary heating means such as an IR heater to control the film temperature to a predetermined temperature, a method of passing the film through an oven adjusted to a predetermined temperature, etc. These methods may be used alone or in combination.

[0123] The stretching ratio in the MD direction is not particularly limited, but is desirably 1.5 times or more to improve the strength and elongation of the film. It is preferably 2 times or more, and more preferably 2.5 times or more. Such a high stretching ratio can be achieved by using the reaction product (A') of a poly(3-hydroxyalkanoate) copolymer with an organic peroxide, or the high molecular weight poly(3-hydroxyalkanoate) copolymer (A-3'). The upper limit of the stretching ratio is usually 8 times or less, but may be 6 times or less.

[0124] Next, by stretching in the MD direction followed by stretching in the TD direction, a biaxially stretched film with high strength in both the MD and TD directions can be obtained. The TD stretching step can be carried out continuously from the MD stretching step in a single production line. This step is not particularly limited, but can be carried out, for example, by clamping both widthwise ends of the film using a transverse stretching machine such as a clip-type tenter and pulling it in the TD direction.

[0125] The stretching step in the TD direction is also preferably carried out while heating the film. The heating method is not particularly limited, and examples thereof include those described above for the stretching step in the MD direction.

[0126] The temperature in the TD stretching step may be the same as the temperature in the MD stretching step described above, but such a temperature is preferably 35 to 150°C, more preferably 45 to 140°C, and more preferably 55 to 130°C.

[0127] The stretching ratio in the TD direction is not particularly limited, but is desirably 1.5 times or more in order to improve the strength and elongation of the film in the TD direction. It is preferably 2 times or more, and more preferably 2.5 times or more. The upper limit of the stretching ratio is usually 8 times or less, but may be 6 times or less.

[0128] After the MD stretching step or the TD stretching step, it is preferable to carry out a heat setting step in which the stretched film is heated to a temperature at which high-melting-point crystals grow, thereby increasing the crystallinity of the film, increasing the strength of the stretched film, and stabilizing the physical properties of the stretched film.

[0129] The heating temperature during heat setting is preferably 80 to 150°C, more preferably 90 to 135°C, and most preferably 100 to 130°C. If the heating temperature is 80°C or higher, the crystallinity of the stretched film increases, and the formed crystals may have a high melting point. If the heating temperature is 150°C or lower, breakage due to melting of the film can be avoided.

[0130] This heating can be carried out, for example, by heating the film while maintaining the stretched state after the stretching step. At this time, since heat shrinkage occurs in the direction opposite to the stretching direction, it is preferable to relax the film to prevent breakage. Relaxation is an operation of returning the tension in the direction opposite to the stretching direction, and it is preferable to appropriately adjust the relaxation amount between 5 and 30%.

[0131] Thereafter, a step of cooling the film may be carried out as appropriate, and then, preferably, a step of winding the film on a winding roll is carried out.

[0132] The extruded film manufacturing method according to this embodiment is preferably carried out while continuously conveying the film from melt extrusion to the final step. This makes it possible to produce the extruded film with good productivity through an industrially simple process. The manufacturing method according to this embodiment can be carried out while continuously winding up the produced extruded film on a winding roll.

[0133] When the extruded film is continuously transported, the transport speed is not particularly limited, but from the viewpoint of film productivity, it is preferably 5 m / min or more at the stage before the start of stretching, and from the viewpoint of production stability, it is preferably 50 m / min or less at the stage before the start of stretching.

[0134] [Laminate] The extruded film according to this embodiment may be a resin film composed of an independent single layer, or may be a laminate formed by laminating other layers on one or both sides of the film. Such a laminate also constitutes one aspect of the present invention. Examples of such other layers include a resin layer, an inorganic layer, a metal layer, a metal oxide layer, a printed layer, etc. These other layers may be laminate layers, coating layers, or vapor-deposited layers.

[0135] The resin layer, which is one of the other layers in the laminate, is not particularly limited, but from the viewpoint of enhancing the biodegradability of the entire laminate, it is preferably a layer containing a poly(3-hydroxyalkanoate)-based resin (C). As the poly(3-hydroxyalkanoate)-based resin (C), the poly(3-hydroxyalkanoate)-based copolymer (A) and poly(3-hydroxybutyrate) (B) described above can be used appropriately, but are not particularly limited. The components other than the poly(3-hydroxyalkanoate)-based resin (C) are also not particularly limited, and known components as additives to resin layers can be used appropriately. This resin layer may function as a heat seal layer.

[0136] [Applications of Film] The film according to this embodiment can be suitably used as a packaging film, a heat-sealable film, a twist film, or the like.

[0137] The following items list preferred embodiments of the present disclosure, but the present invention is not limited to each of them. [Item 1] An extruded film containing a poly(3-hydroxyalkanoate) copolymer (A) and a poly(3-hydroxybutyrate) (B). [Item 2] The extruded film according to Item 1, wherein the poly(3-hydroxyalkanoate) copolymer (A) comprises at least two poly(3-hydroxyalkanoate) copolymers that differ from each other in the type of constituent monomer and / or the content ratio of the constituent monomer. [Item 3] The extruded film according to Item 1 or 2, wherein the poly(3-hydroxyalkanoate) copolymer (A) comprises a copolymer (A-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, wherein the content ratio of the other hydroxyalkanoate units is 24 mol % or more. [Item 4] The extruded film according to item 3, wherein the content of poly(3-hydroxybutyrate) (B) is 2 to 75 wt% of the total weight of the poly(3-hydroxyalkanoate)-based copolymer (A) and the poly(3-hydroxybutyrate) (B). [Item 5] The extruded film according to item 3 or 4, wherein the content of copolymer (A-1) is 5 to 85 wt% of the total weight of the poly(3-hydroxyalkanoate)-based copolymer (A) and the poly(3-hydroxybutyrate) (B). [Item 6] The extruded film according to any one of items 3 to 5, wherein the poly(3-hydroxyalkanoate)-based copolymer (A) further contains a copolymer (A-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of the other hydroxyalkanoate units being 1 mol% or more and less than 5 mol%. [Item 7] The extruded film according to any one of Items 3 to 6, wherein the poly(3-hydroxyalkanoate) copolymer (A) further comprises a copolymer (A-3) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of the other hydroxyalkanoate units being 5 mol% or more and less than 24 mol%. [Item 8] The extruded film according to any one of Items 3 to 7, wherein the extruded film is a T-die film.[Item 9] The extruded film according to item 1 or 2, wherein the poly(3-hydroxyalkanoate) copolymer (A) comprises a reaction product (A') of a poly(3-hydroxyalkanoate) copolymer and an organic peroxide. [Item 10] The extruded film according to item 9, wherein the reaction product (A') comprises a reaction product of an organic peroxide and a copolymer (A-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 24 mol% or more. [Item 11] The extruded film according to item 10, wherein the amount of copolymer (A-1) is 5 to 60 wt% of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B). [Item 12] The extruded film according to any one of items 9 to 11, wherein the content of poly(3-hydroxybutyrate) (B) is 5 to 60 wt % of the total weight of the poly(3-hydroxyalkanoate)-based copolymer (A) and the poly(3-hydroxybutyrate) (B). [Item 13] The extruded film according to any one of items 9 to 12, wherein the poly(3-hydroxybutyrate) (B) is a reaction product with an organic peroxide. [Item 14] The extruded film according to any one of items 9 to 13, wherein the poly(3-hydroxyalkanoate)-based copolymer (A) further comprises a copolymer (A-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of the other hydroxyalkanoate units being 1 mol % or more and less than 5 mol %. [Item 15] The extruded film according to item 14, wherein the reactant (A') comprises a reaction product of the copolymer (A-2) with an organic peroxide. [Item 16] The extruded film according to any one of items 9 to 15, wherein the poly(3-hydroxyalkanoate) copolymer (A) comprises a copolymer (A-3) of 3-hydroxybutyrate units and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 5 mol% or more and less than 24 mol%. [Item 17] The extruded film according to item 16, wherein the reactant (A') comprises a reaction product of the copolymer (A-3) and an organic peroxide. [Item 18] The extruded film according to any one of items 9 to 17, wherein the extruded film is a stretched film.[Item 19] The extruded film according to Item 1 or 2, wherein the poly(3-hydroxyalkanoate) copolymer (A) contains a copolymer (A-3') of 3-hydroxybutyrate units and other hydroxyalkanoate units, the copolymer (A-3') having a weight-average molecular weight of 700,000 or more and containing 5 mol% or more but less than 24 mol% of other hydroxyalkanoate units, and the content of copolymer (A-3') is 20 to 80 wt% of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and the poly(3-hydroxybutyrate) (B), and the content of poly(3-hydroxybutyrate) (B) is 5 to 60 wt% of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and the poly(3-hydroxybutyrate) (B). [Item 20] The extruded film according to item 19, wherein the poly(3-hydroxyalkanoate) copolymer (A) further comprises a copolymer (A-3") of 3-hydroxybutyrate units and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 5 mol% or more but less than 24 mol% and the weight average molecular weight is less than 700,000. [Item 21] The extruded film according to item 19 or 20, wherein the extruded film is a stretched film. [Item 22] The extruded film according to any one of items 1 to 21, wherein the other hydroxyalkanoate units comprise 3-hydroxyhexanoate units. [Item 23] The extruded film according to any one of items 1 to 22, further containing talc and / or a fatty acid amide. [Item 24] The extruded film according to any one of items 1 to 23, which is substantially free of sugar alcohols.

[0138] EXAMPLES The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[0139] In each example and comparative example, the following raw materials were used. (Poly(3-hydroxyalkanoate)-based copolymer (A)) As the P3HA-based copolymer (A), the following poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH) PHBH-1 to PHBH-3 were used. 3HB represents a 3-hydroxybutyrate repeating unit, and 3HH represents a 3-hydroxyhexanoate repeating unit. PHBH-1 (A-1): P3HB3HH (average content ratio 3HB / 3HH = 71.8 / 28.2 (mol% / mol%), weight average molecular weight 660,000 g / mol) Produced in accordance with the method described in Example 9 of WO 2019 / 142845. PHBH-2 (A-2): P3HB3HH (average content ratio 3HB / 3HH = 97.2 / 2.8 (mol% / mol%), weight average molecular weight is 660,000 g / mol) Produced in accordance with the method described in Example 1 of WO 2019 / 142845. PHBH-3 (A-3): P3HB3HH (average content ratio 3HB / 3HH = 94 / 6 (mol% / mol%), weight average molecular weight is 780,000 g / mol) Produced in accordance with the method described in WO 2008 / 010296. PHBH-4 (A-3): P3HB3HH (average content ratio 3HB / 3HH = 89 / 11 (mol% / mol%), weight average molecular weight is 350,000 g / mol) Produced in accordance with the method described in WO 2008 / 010296.

[0140] (Poly(3-hydroxybutyrate) (B)) The following PHB was used as P3HB (B): PHB: Poly(3-hydroxybutyrate) (weight average molecular weight: 350,000 g / mol) Produced in accordance with the method described in Comparative Example 1 of WO 2004 / 041936.

[0141] (Inorganic filler) C-1: Talc [SG-200N15, manufactured by Nippon Talc]

[0142] (Lubricant) C-2: Behenic acid amide (manufactured by Nippon Fine Chemical Co., Ltd.: BNT-22H)

[0143] The following evaluations were carried out for each example and comparative example. <T-die film formability> The T-die film formability was evaluated according to the following evaluation criteria based on the take-up speed of the T-die film during production of the T-die film. ◯: Take-up speed is 3 m / min or more Δ: Take-up speed is 1 m / min or more ×: Take-up speed is less than 1 m / min

[0144] <Elastic Modulus, Tensile Strength, and Elongation at Break of Film> After storing the film to be evaluated at 50°C for 3 days, five dumbbells (JIS K7113-2(1 / 3) type) in the MD and / or TD directions were punched out in accordance with JIS K7113, and the elastic modulus, tensile strength, and elongation at break were measured and calculated five times using a tensile tester ("EZ Test EZ-LX" manufactured by Shimadzu Corporation) at a test speed of 100 mm / min, and the average values ​​were reported in the tables as the elastic modulus, tensile strength, and elongation at break.

[0145] <Film Tear Strength> After storing the film to be evaluated at 50°C for 3 days, the tear strength was measured using the Elmendorf tear method based on JIS K-7128-2. The measurement was performed five times, and the average value was reported in the table as the tear strength.

[0146] (Example 1) (Method of producing resin composition) 30 parts by weight of poly(3-hydroxyalkanoate) resin PHBH-1, 30 parts by weight of PHBH-2, 20 parts by weight of PHBH-3, 7 parts by weight of PHBH-4, and 13 parts by weight of PHB were dry-blended with 1 part by weight of C-1 as an inorganic filler and 1 part by weight of C-2 as a lubricant. The resulting resin material was charged into the hopper of a φ26 mm co-rotating twin-screw extruder with the cylinder temperature and die temperature set to 160 ° C, melt-kneaded, extruded through the die into strands, passed through a water tank filled with hot water at 45 ° C to solidify the strands, and cut with a pelletizer to obtain resin pellets P-1.

[0147] (Production of T-die Film) The cylinder temperature and die temperature of a φ40 mm single-screw extruder connected to a 350 mm wide T-die were each set to 170°C. The resin pellets P-1 were charged into the single-screw extruder and extruded into a film using a T-die. The formed film was cooled using a cooling roll (φ250 mm) set at a temperature of 60°C and then taken up using a take-up roll to produce a 60 μm thick T-die film. T-die film moldability was evaluated during T-die film production, and the results are shown in Table 1. The obtained T-die film was evaluated for elastic modulus, tensile strength, elongation at break, and tear strength, and the results are shown in Table 1.

[0148] (Examples 2 to 4) Resin pellets were produced in the same manner as in Example 1, except that the formulation was changed as shown in Table 1. Films were produced in the same manner as in Example 1, and the T-die film formability, elastic modulus, breaking stress, breaking elongation, and tear strength were evaluated. The evaluation results are shown in Table 1.

[0149] In Examples 1 to 3, film formation was possible at a take-up speed of 3.5 m / min without the resin material sticking to the cooling roll. In Example 4, the forming speed could only be increased to 1 m / min, but continuous film production was possible.

[0150] Comparative Example 1 Resin pellets were produced in the same manner as in Example 1, except that the formulation was changed as shown in Table 1. An attempt was made to produce a film in the same manner as in Example 1, but a T-die film could not be obtained because the pellets stuck to the cooling roll or the like.

[0151]

[0152] From Table 1, it can be seen that extruded films could be produced continuously with good productivity in Examples 1 to 4. In particular, the productivity was good in Examples 1 to 3. On the other hand, in Comparative Example 1, poly(3-hydroxybutyrate) (B) was not blended, and the molten resin material stuck to the cooling roll, making it impossible to produce a film continuously.

[0153] In each of the Examples and Comparative Examples shown in Table 2, in addition to the above-mentioned raw materials, the following raw materials were used: (Organic peroxide) E-1: Perbutyl I (t-butylperoxyisopropyl carbonate, 1-minute half-life temperature: 159°C) manufactured by NOF Corporation

[0154] (Example 5) (Method of producing resin composition) Poly (3-hydroxyalkanoate) resin PHBH-1 7.5 parts by weight, PHBH-2 7.5 parts by weight, PHBH-3 65 parts by weight, PHBH-4 7 parts by weight, PHB 13 parts by weight, C-1 1.0 parts by weight as an inorganic filler, C-2 1.0 parts by weight as a lubricant, E-1 0.2 parts by weight as an organic peroxide were dry blended. The resulting resin material was charged into a φ26 mm co-rotating twin-screw extruder hopper with the cylinder temperature and die temperature set to 160 ° C., melt-kneaded, extruded onto a strand from the die, passed through a water bath filled with hot water at 45 ° C. to solidify the strand, and cut with a pelletizer to obtain resin pellets P-2. Note that during the melt-kneading process, the reaction between the P3HA copolymer (A) and the organic peroxide proceeded, forming a reaction product (A').

[0155] (Production of uniaxially stretched film in the MD direction) The cylinder temperature and die temperature of a φ40 mm single-screw extruder connected to a 350 mm wide T-die were each set to 170 ° C. The resin pellets P-2 were charged into the single-screw extruder and extruded into a film using a T-die. The formed film was cooled using a cooling roll set at 60 ° C. and then taken up using a take-up roll to produce a T-die film. The film was then continuously stretched 2.5 times in the machine direction (MD) at a stretching temperature of 135 ° C. using a roll longitudinal stretching machine to produce a stretched film with a thickness of 30 μm. The T-die film moldability was evaluated based on the take-up speed of the T-die film during production, and the results are shown in Table 2. The resulting stretched film was evaluated for elastic modulus, breaking stress, breaking elongation, and tear strength, and the results are shown in Table 2.

[0156] (Examples 6 and 7) Resin pellets were produced in the same manner as in Example 5, except that the formulation was changed as shown in Table 2. Films were also produced in the same manner as in Example 5, and the T-die film formability, elastic modulus, breaking stress, breaking elongation, and tear strength were evaluated. In this case, the film stretching temperature was changed appropriately between 60 and 140°C. The evaluation results are shown in Table 2.

[0157] Example 8 The T-die film before the stretching step in Example 5 was evaluated for modulus of elasticity, breaking stress, breaking elongation, and tear strength. The results are shown in Table 2.

[0158] (Example 9) Resin pellets were produced in the same manner as in Example 5, except that the formulation was changed as shown in Table 2. Film production was also carried out in the same manner as in Example 5, and T-die film moldability was evaluated. Furthermore, an attempt was made to produce a stretched film in the same manner as in Example 5, but the film broke during stretching, and it was not possible to produce a stretched film.

[0159] Comparative Example 2 Resin pellets were produced in the same manner as in Example 5, except that the formulation was changed as shown in Table 2. An attempt was made to produce a film in the same manner as in Example 5, but a T-die film could not be obtained because the pellets stuck to the cooling roll or the like.

[0160]

[0161] Table 2 shows that in Examples 5 to 9, extruded films were continuously produced with good productivity. In particular, in Examples 5 to 7, in which the reaction product (A') of a poly(3-hydroxyalkanoate) copolymer with an organic peroxide and poly(3-hydroxybutyrate) (B) were used in combination, not only was film productivity good, but stretchability was also good. On the other hand, in Example 9, in which the poly(3-hydroxyalkanoate) copolymer (A) that had not been reacted with an organic peroxide was used in combination with poly(3-hydroxybutyrate) (B), film productivity was good, but the film broke during the stretching process, making it impossible to obtain a stretched film. Furthermore, in Comparative Example 2, in which the reaction product (A') of a poly(3-hydroxyalkanoate) copolymer with an organic peroxide was used but poly(3-hydroxybutyrate) (B) was not used, the molten resin material stuck to the cooling roll, making it impossible to produce a film continuously.

[0162] In each of the Examples and Comparative Examples shown in Table 3, in addition to the raw materials described above, the following raw materials were used: PHBH-5 (A-3'): P3HB3HH (average content ratio 3HB / 3HH = 88.9 / 11.1 (mol % / mol %), weight average molecular weight 780,000 g / mol) Produced in accordance with the method described in the Examples (raw material A-3) of WO 2013 / 147139.

[0163] (Example 10) (Method of producing resin composition) 30 parts by weight of poly(3-hydroxyalkanoate) resin PHBH-3, 7 parts by weight of PHBH-4, 50 parts by weight of PHBH-5, and 13 parts by weight of PHB were dry-blended with 1 part by weight of C-1 as an inorganic filler and 1 part by weight of C-2 as a lubricant. The resulting resin material was charged into a hopper of a φ26 mm co-rotating twin-screw extruder with a cylinder temperature and a die temperature set to 160 ° C., melt-kneaded, extruded into strands from the die, passed through a water tank filled with hot water at 45 ° C. to solidify the strands, and cut with a pelletizer to obtain resin pellets P-3.

[0164] (Production of uniaxially stretched film in the MD direction) The cylinder temperature and die temperature of a φ40 mm single-screw extruder connected to a 350 mm wide T-die were each set to 170 ° C. The resin pellets P-3 were charged into the single-screw extruder and extruded into a film using a T-die. The formed film was cooled with a cooling roll set at a temperature of 50 ° C. and then taken up with a take-up roll to produce a T-die film. The film was continuously stretched in the longitudinal (MD) direction at a stretching temperature of 135 ° C. using a roll longitudinal stretching machine to produce a stretched film with a thickness of 30 μm. The T-die film moldability was evaluated based on the take-up speed of the T-die film during production, and the results are shown in Table 3. The obtained stretched film was evaluated for elastic modulus, breaking stress, breaking elongation, and tear strength, and the results are shown in Table 3.

[0165] (Examples 11 and 12) Resin pellets were produced in the same manner as in Example 10, except that the formulation was changed as shown in Table 3. Films were also produced in the same manner as in Example 10, and the T-die film formability, elastic modulus, breaking stress, breaking elongation, and tear strength were evaluated. The film stretching temperature and cooling roll temperature were adjusted as appropriate. The evaluation results are shown in Table 3.

[0166] (Examples 13 to 16) Resin pellets were produced in the same manner as in Example 10, except that the formulation was changed as shown in Table 3. Film production was also carried out in the same manner as in Example 10, and T-die film moldability was evaluated. Furthermore, an attempt was made to produce a stretched film in the same manner as in Example 10, but the film broke during stretching, and it was not possible to produce a stretched film.

[0167] Comparative Example 3 Resin pellets were produced in the same manner as in Example 10, except that the formulation was changed as shown in Table 3. An attempt was made to produce a film in the same manner as in Example 10, but a T-die film could not be obtained because the pellets stuck to the cooling roll or the like.

[0168]

[0169] Table 3 shows that in Examples 10 to 16, extruded films could be continuously produced with good productivity. In particular, in Examples 10 to 12, in which specific amounts of poly(3-hydroxyalkanoate) copolymer (A-3') and poly(3-hydroxybutyrate) (B) were used in combination, not only was film productivity good, but stretchability was also good. On the other hand, in Examples 13 to 16, although film productivity was good, the film broke during the stretching process, making it impossible to obtain a stretched film. Furthermore, in Comparative Example 3, in which poly(3-hydroxybutyrate) (B) was not used, the molten resin material stuck to the cooling roll, making it impossible to continuously produce film.

Claims

1. Poly(3-hydroxyalkanoate) copolymer (A), Poly(3-hydroxybutyrate)(B), and, It contains inorganic fillers and / or fatty acid amides, An extruded film that is substantially free of sugar alcohols.

2. The extruded film according to claim 1, wherein the poly(3-hydroxyalkanoate) copolymer (A) comprises at least two poly(3-hydroxyalkanoate) copolymers having different types of constituent monomers and / or proportions of constituent monomers.

3. The extruded film according to claim 1 or 2, wherein the poly(3-hydroxyalkanoate) copolymer (A) comprises a copolymer (A-1) of a 3-hydroxybutyrate unit and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 24 mol% or more.

4. The extruded film according to claim 3, wherein the content of poly(3-hydroxybutyrate)(B) is 2 to 75% by weight of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate)(B).

5. The extruded film according to claim 3, wherein the content of copolymer (A-1) is 5 to 85% by weight of the total weight of poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B).

6. The extruded film according to claim 3, wherein the poly(3-hydroxyalkanoate) copolymer (A) further comprises a copolymer (A-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 1 mol% or more and less than 5 mol%.

7. The extruded film according to claim 3, wherein the poly(3-hydroxyalkanoate) copolymer (A) further comprises a copolymer (A-3) of 3-hydroxybutyrate units and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 5 mol% or more and less than 24 mol%.

8. The extruded film according to claim 3, wherein the extruded film is a T-die film.

9. The extruded film according to claim 1 or 2, wherein the poly(3-hydroxyalkanoate) copolymer (A) comprises a reaction product (A') of the poly(3-hydroxyalkanoate) copolymer and an organic peroxide.

10. The extruded film according to claim 9, wherein the reactant (A') comprises a reaction product of an organic peroxide and a copolymer (A-1) of a 3-hydroxybutyrate unit and other hydroxyalkanoate units, in which the content of other hydroxyalkanoate units is 24 mol% or more.

11. The extruded film according to claim 10, wherein the amount of copolymer (A-1) is 5 to 60% by weight of the total weight of poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B).

12. The extruded film according to claim 9, wherein the content of poly(3-hydroxybutyrate)(B) is 5 to 60% by weight of the total weight of the poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate)(B).

13. The extruded film according to claim 9, wherein poly(3-hydroxybutyrate)(B) is a reaction product with an organic peroxide.

14. The extruded film according to claim 9, wherein the poly(3-hydroxyalkanoate) copolymer (A) further comprises a copolymer (A-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 1 mol% or more and less than 5 mol%.

15. The extruded film according to claim 14, wherein the reactant (A') comprises a reaction product of copolymer (A-2) and an organic peroxide.

16. The extruded film according to claim 9, wherein the poly(3-hydroxyalkanoate) copolymer (A) comprises a copolymer (A-3) of a 3-hydroxybutyrate unit and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 5 mol% or more and less than 24 mol%.

17. The extruded film according to claim 16, wherein the reactant (A') comprises a reaction product of copolymer (A-3) and an organic peroxide.

18. The extruded film according to claim 9, wherein the extruded film is a stretched film.

19. The poly(3-hydroxyalkanoate) copolymer (A) includes a copolymer (A-3') of a 3-hydroxybutyrate unit and another hydroxyalkanoate unit, wherein the content of other hydroxyalkanoate units is 5 mol% or more and less than 24 mol%, and the weight-average molecular weight is 700,000 or more. The content of copolymer (A-3') is 20 to 80% by weight of the total weight of poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate) (B). The extruded film according to claim 1 or 2, wherein the content of poly(3-hydroxybutyrate)(B) is 5 to 60% by weight of the total weight of poly(3-hydroxyalkanoate) copolymer (A) and poly(3-hydroxybutyrate)(B).

20. The extruded film according to claim 19, wherein the poly(3-hydroxyalkanoate) copolymer (A) further comprises a copolymer (A-3") of a 3-hydroxybutyrate unit and other hydroxyalkanoate units, wherein the content of other hydroxyalkanoate units is 5 mol% or more and less than 24 mol%, and the weight-average molecular weight is less than 700,000.

21. The extruded film according to claim 19, wherein the extruded film is a stretched film.

22. The extruded film according to claim 1 or 2, wherein the other hydroxyalkanoate unit includes a 3-hydroxyhexanoate unit.