Aliphatic polyester film, package, material for agriculture, forestry and fisheries industries, and material for agriculture, forestry and fisher

Abstract

To provide a film containing an aliphatic polyester which is excellent in biodegradability, processability, quietness and barrier properties and can be suitably used for packaging applications and agricultural, forestry and fishery applications.SOLUTION: The aliphatic polyester film contains at least a polyhydroxyalkanoic acid and has a loss tangent (tan δ (30)) of ≥ 0.05 and ≤ 0.15 at 30 °C in dynamic viscoelasticity measurement and a maximum peak temperature of the loss tangent of ≥ 30 °C and ≤ 100 °C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an aliphatic polyester film, a packaging material, an agricultural, forestry and fisheries material, and an agricultural, forestry and fisheries ingredient. [Background technology]

[0002] From the perspective of curbing global warming, various efforts are underway around the world to achieve carbon neutral goals, and there is a particular need to reduce the amount of plastic products used and disposed of, as they emit a large amount of CO2 during their manufacture and disposal.Plastic packaging is used in particularly large quantities among various plastic products, and much of it is disposable, so there is a need to reduce the amount of packaging plastics used and disposed of, including film, and to recycle and replace them with plant-derived materials.

[0003] In recent years, the environmental pollution problem of plastics entering the ocean has also been attracting attention. For example, fish, seabirds, and marine mammals have died after accidentally ingesting plastic products that have drifted into the ocean. Microplastics, which have been broken down by waves and ultraviolet light, are bioaccumulated in the marine food chain, posing a risk to humans who consume fish and other marine life. These issues are caused by improperly disposed plastic packaging and plastic materials used in agriculture that find their way into the ocean via rivers, and by plastic materials dumped after use in fishing and aquaculture that drift in the ocean. Therefore, there is a need to make plastics biodegradable in case packaging plastics and plastics used in agriculture, forestry, and fisheries are not disposed of properly.

[0004] The use of biodegradable plastics is expected to address this type of marine pollution caused by plastics, but a report compiled by the United Nations Environment Programme in 2015 pointed out that compostable plastics such as polylactic acid cannot be expected to decompose in a short period of time in the cold ocean, making them ineffective as a countermeasure against marine pollution. In this context, among biodegradable plastics, aliphatic polyester resins have attracted particular attention due to their high biodegradability, and their application as packaging materials is being considered. Patent Documents 1 to 4 propose films with excellent toughness that are produced by blending polylactic acid resin with resins such as polybutylene succinate, polybutylene adipate terephthalate, 3-hydroxybutyrate-co-3-hydroxyhexanoate copolymer, and polyhydroxyalkanoic acid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2014-514372 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-131687 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-126701 [Patent Document 4] Japanese Patent Application Publication No. 2022-62759 Summary of the Invention [Problem to be solved by the invention]

[0006] However, polyhydroxyalkanoic acid films are generally difficult to stretch, and have inferior mechanical strength and thermal dimensional stability compared to polyolefin and polyester films. Therefore, for example, when the contents are shaken during transportation, the packaging film may break, resulting in insufficient protection of the contents. Furthermore, because the film is extremely susceptible to deformation, cracks may form in the vapor-deposited layer during the metal vapor deposition process, impairing the water vapor barrier and oxygen barrier properties. Furthermore, when used as a packaging material in applications where handling and bending are frequent, such as snack packaging, quietness of the film is becoming a requirement. However, compared to other thermoplastic resin packaging films, such as polyolefins, polylactic acid films are hard and brittle, resulting in a distinctive, harsh sound when subjected to external stress, such as crumpling or bending.

[0007] In Patent Document 1, the composition contains 70% or more by weight of polylactic acid, so it is not sufficiently biodegradable or quiet when used in home composting, where the composition is buried in soil for composting. In Patent Documents 2 and 3, the addition of a plasticizer to the polylactic acid gives it flexibility and improves processability, but the biodegradability in home composting is not sufficient. The film described in Patent Document 4 lacks mechanical properties and breaks during transport for vapor deposition processing, leaving room for improvement in processability.

[0008] Therefore, an object of the present invention is to provide a film containing an aliphatic polyester that is excellent in barrier properties (particularly when aluminum is vapor-deposited) in addition to being biodegradable and processable. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems and have come up with the following film of the present invention. That is, one preferred embodiment of the present invention is as follows. 1. An aliphatic polyester film containing at least polyhydroxyalkanoic acid, having a loss tangent (tanδ(30)) at 30°C in dynamic viscoelasticity measurement of 0.05 or more and 0.15 or less, and having a maximum peak temperature of the loss tangent of 30°C or more and 100°C or less. 2. The aliphatic polyester film according to 1., which comprises at least two layers: an X layer containing an aliphatic polyester film, and a Y layer different from the X layer. 3. An aliphatic polyester film according to 1. or 2., wherein when the thermal shrinkage rate at 120°C in the longitudinal direction is H1 (%) and the thermal shrinkage rate at 120°C in the width direction is H2 (%), H1 and H2 are both 0% or more and 20% or less. 4. The aliphatic polyester film according to any one of 1. to 3., wherein tan δ(A) is the maximum peak of the loss tangent in the temperature range of -30°C or higher and 30°C or lower, and tan δ(B) is the maximum peak of the loss tangent in the temperature range of 40°C or higher and 100°C or lower, and tan δ(A) and tan δ(B) satisfy formula (1):

[0010] 0.8≦tanδ(B) / tanδ(A)≦10...Equation (1) 5. The aliphatic polyester film according to any one of 1. to 4., which has a loss tangent (tan δ(60)) at 60°C of 0.10 or more. 6. An aliphatic polyester film according to any one of 1. to 5., wherein, in wide-angle X-ray diffraction in the thickness direction using CuKα radiation, the crystallite size calculated from the half-width of PB is 5 nm or more and 60 nm or less, when the peak with the highest intensity among peaks with an orientation degree of 0.50 or more in the diffraction angle 2θ range of 19° or more and 21° or less is defined as PB. 7. The aliphatic polyester film according to any one of 1. to 6., wherein, when the breaking elongation in the longitudinal direction is S1 (MPa) and the breaking elongation in the width direction is S2 (MPa), S1 and S2 are both 30 MPa or more and 280 MPa or less. 8. The aliphatic polyester film according to any one of 1. to 7., wherein, when the breaking elongation in the longitudinal direction is L1 (%) and the breaking elongation in the width direction is L2 (%), L1 and L2 are both 10% or more and 350% or less. 9. The aliphatic polyester film according to any one of 1. to 8., which contains 45% by mass or more of polyhydroxyalkanoic acid relative to 100% by mass of the total mass of the film. 10. The aliphatic polyester film according to any one of 1. to 9., which contains, relative to the total mass of the film (100% by mass), 1% by mass to 45% by mass of a crystalline polylactic acid-based resin and 1% by mass to 45% by mass of an amorphous polylactic acid-based resin and / or a plasticizer for polylactic acid-based resin. 11. The aliphatic polyester film according to 2., wherein the polyhydroxyalkanoic acid content is 45% by mass or more relative to 100% by mass of the total mass of the X layer. 12. The aliphatic polyester film according to 2. or 11., which contains 1% by mass or more and 45% by mass or less of a crystalline polylactic acid-based resin and 1% by mass or more and 45% by mass or less of an amorphous polylactic acid-based resin and / or a plasticizer for polylactic acid-based resin, relative to 100% by mass of the total mass of the X layer. 13. The aliphatic polyester film according to 2., wherein the Y layer includes any one of an adhesive layer, a pressure-sensitive adhesive layer, a printing layer, and a heat-sealing layer. 14. The aliphatic polyester film according to any one of 1. to 13., further comprising a functional layer on at least one surface thereof. 15. A package comprising the aliphatic polyester film according to any one of 1. to 14. 16. An agricultural, forestry and fisheries material comprising the aliphatic polyester film according to any one of 1. to 14. 17. The aliphatic polyester film according to any one of 1. to 14., which is a film used to cover agricultural, forestry and fishery materials, wherein the agricultural, forestry and fishery materials include one or more selected from fertilizers, feeds, seeds and seedlings, and chemicals. 18. An agricultural, forestry and fishery material, characterized by being covered with the aliphatic polyester film according to any one of 1. to 14. [Effects of the Invention]

[0011] The aliphatic polyester film obtained by the present invention is biodegradable, processable, quiet, and has excellent barrier properties (particularly when aluminum is vapor-deposited), making it suitable for use in packaging and agriculture, forestry, and fisheries. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a graph showing tan δ for an example of a film of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The film of the present invention will be described in detail below. Hereinafter, when the upper and lower limits of a preferred range are separately stated, they may be combined in any manner. Furthermore, the "aliphatic polyester film of the present invention" may be collectively referred to as "the present invention" or "the film of the present invention." Furthermore, in the film of the present invention, the "thickness direction" refers to the direction perpendicular to the film surface. The "longitudinal direction" refers to the direction corresponding to the flow direction in the film production process (hereinafter, sometimes referred to as "MD"), and the "width direction" refers to the direction perpendicular to the flow direction in the film production process within the film plane (hereinafter, sometimes referred to as "TD"). When a film sample is in the form of a reel or roll, the film winding direction can be considered the longitudinal direction. When the stretching direction (longitudinal direction and width direction) is unknown, the breaking strength at break can be measured in the mechanical property evaluation described below, and the direction of the main orientation axis with the largest measured value can be considered the longitudinal direction in the present invention, and the direction perpendicular to the main orientation axis can be considered the width direction. Details will be described later.

[0014] Aliphatic polyesters constituting a preferred embodiment of the film of the present invention include polyhydroxyalkanoic acid, polylactic acid, polyglycolic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, polycaprolactone, etc., and among these, the inclusion of at least polyhydroxyalkanoic acid is important from the viewpoint of obtaining excellent biodegradability in a home composting environment. Here, polyhydroxyalkanoic acid refers to a polymer containing hydroxyalkanoic acid as a constituent component, such as a 3-hydroxyalkanoate repeating unit represented by the general formula [-CHR-CH2-CO-O-] (wherein R is Cn H 2n+1 where n is an integer of 1 to 15.) and poly(3-hydroxyalkanoates) (hereinafter, also referred to as "P3HA") containing the alkyl group represented by the formula:

[0015] Examples of P3HA include poly(3-hydroxybutyrate) (P3HB), poly(3-hydroxyvalerate) (P3HV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P3HB3HV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (P3HB3HV3HH), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (P3HB3HO), and poly(3-hydroxybutyrate-co-3-hydroxydecanoate) (P3HBP3HD). Note that "-co-" means copolymerized.

[0016] P3HA may be either chemically synthesized (for example, obtained by ring-opening polymerization of the corresponding lactone) or produced by a microorganism, but P3HA produced by a microorganism is preferred from the viewpoint of ease of production using biomass raw materials such as vegetable oil. Among P3HA produced by a microorganism, P3HB, P3HB3HH, P3HB3HV, P3HB3HV3HH, and P3HB4HB are preferably used from the viewpoint of ease of industrial production.

[0017] The melting point and crystallinity of polyhydroxyalkanoates, including P3HA, can be adjusted by changing the composition ratio of the repeating units. Polyhydroxyalkanoates are generally known to be prone to thermal decomposition, but by designing a copolymer structure of two or more types of hydroxyalkanoates to have a low melting point, it is possible to lower the extrusion processing temperature.

[0018] In a preferred embodiment of the film of the present invention, the loss tangent (tan δ(30)) at 30°C in dynamic viscoelasticity measurement is 0.05 or more and 0.15 or less. This embodiment allows for a film that is easily biodegradable in home composting. This is believed to be because a tan δ(30) of 0.05 or more facilitates the movement of amorphous molecular chains in the film at room temperature. The tan δ(30) can be controlled by controlling the amorphous structure of the polyhydroxyalkanoic acid resin in the film of the present invention. From the viewpoints of biodegradability and quietness, the tan δ(30) is preferably 0.06 or more, more preferably 0.07 or more. On the other hand, if the tan δ(30) is too large, the film may become too flexible at room temperature, resulting in insufficient strength. During transport, the film may be overstretched by the transport tension between the rolls, resulting in wrinkles. Therefore, the tan δ(30) is preferably 0.14 or less, more preferably 0.13 or less. The loss tangent obtained by dynamic viscoelasticity measurement is determined by the method described in the examples.

[0019] The method for controlling tan δ(30) within the above range is not particularly limited, but examples include, as described below, blending a polyhydroxyalkanoic acid resin with a crystalline polylactic acid resin and an amorphous polylactic acid resin and / or a plasticizer for polylactic acid resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid to control the amount of amorphous components that are mobile at 30°C, or employing the above method while increasing the temperature of the supply section of the extruder cylinder to a low temperature and the compression section to a high temperature during film production to improve the dispersion state.

[0020] In a preferred embodiment of the film of the present invention, the maximum peak temperature of the loss tangent is 30°C or higher and 100°C or lower. Here, the maximum peak is defined as the temperature at which the maximum extreme value (hereinafter referred to as the "maximum extreme value") of the tan δ-temperature curve in the range of 30°C or higher and 100°C or lower and the minimum value of tan δ in the range of 30°C or higher and 100°C or lower are divided by the minimum value, and the maximum peak temperature is defined as the temperature at which the value obtained by dividing the maximum extreme value by the minimum value is 2.0 or higher. If the value obtained by dividing the maximum extreme value by the minimum value is less than 2.0, the film is deemed to have no maximum peak. This embodiment, combined with a tan δ(30) of 0.05 or higher and 0.15 or lower, allows the film to follow suit with appropriate flexibility and rigidity, suppressing breakage and providing excellent processability when subjected to conveyance tension fluctuations in an environment where the film is exposed to heat of 30°C or higher, such as in the process of processing the film into packaging bags. Furthermore, suppressing wrinkling during vapor deposition improves the quality of the vapor-deposited film, thereby improving the barrier properties after vapor deposition. This is thought to be due to the presence of an amorphous structure in the film that makes it difficult for glass transition to occur at low temperatures.

[0021] From the above viewpoint, the maximum peak temperature of the loss tangent is preferably 35°C or higher, more preferably 40°C or higher, and even more preferably 45°C or higher. On the other hand, if the maximum peak temperature of the loss tangent is too high, the resulting film is likely to have poor biodegradability. Therefore, the maximum peak temperature is preferably 90°C or lower, more preferably 80°C or lower, and particularly preferably 70°C or lower. Methods for controlling the maximum peak temperature of the loss tangent within the above range are not particularly limited, but examples include blending a polyhydroxyalkanoic acid resin with an aliphatic polyester resin other than polyhydroxyalkanoic acid, such as a crystalline polylactic acid resin and an amorphous polylactic acid resin and / or a plasticizer for polylactic acid resin, as described below, or employing the above method while biaxially stretching the film to an areal stretching ratio of 2.3 times or higher, thereby restraining and stabilizing the oriented crystallization of molecular chains and the strained amorphous molecular chains that accompany stretching. Here, the film for which dynamic viscoelasticity is evaluated may be a single-layer or multilayer laminate, and measurements are performed on the film. In the case of a laminate such as a laminate of multiple sheets, when an aliphatic polyester film containing polyhydroxyalkanoic acid is sampled and the layer is measured, it is preferable that tan δ(30) is 0.05 or more and 0.15 or less, and the maximum peak temperature of the loss tangent is 30°C or more and 100°C or less.

[0022] The film of the present invention is preferably a laminated aliphatic polyester film comprising two layers: an X layer containing an aliphatic polyester, and a Y layer different from the X layer, from the viewpoint of excellent biodegradability, processability, quietness, and barrier properties, and being suitable for use in packaging and agricultural, forestry, and fisheries applications. From the viewpoint of production costs and use as a quiet packaging material, it is preferable that the Y layer comprises one of an adhesive layer, a pressure-sensitive adhesive layer, a printing layer, and a heat-seal layer. Here, "different" refers to differences in either the optical properties or thermal properties of the aliphatic polyester film layers constituting each layer. "Different optical properties" refers to refractive indices differing by 0.01 or more, and "different thermal properties" refers to melting points or glass transition temperatures differing by 1°C or more.

[0023] In the film of the present invention, when the 120°C heat shrinkage rate in the longitudinal direction is H1 (%) and the 120°C heat shrinkage rate in the transverse direction is H2 (%), it is preferable that H1 and H2 are both 0% to 20%. By setting both H1 and H2 to 0% or more, wrinkles and sagging due to thermal expansion during high-speed processing can be prevented, improving the quality of the vapor-deposited film and resulting in a film with excellent barrier properties. Furthermore, by setting both H1 and H2 to 20% or less, film shrinkage due to heat when processing a vapor-deposited layer on the surface as a functional layer can be prevented, cracks in the vapor-deposited layer can be suppressed, and deterioration of gas barrier properties can be prevented. From the above viewpoints, both H1 and H2 are more preferably 15% or less, even more preferably 9% or less, and particularly preferably 6% or less. While the lower limits of H1 and H2 are not particularly limited, from the viewpoint of preventing wrinkles and sagging due to thermal expansion during high-speed processing, both H1 and H2 are more preferably 0.1% or more, even more preferably 0.3% or more. In this specification, the heat shrinkage rate is defined as the percentage change in film length before and after heat treatment of a film in a predetermined direction at 120°C for 15 minutes, and is measured specifically by the method described in the Examples. Methods for controlling H1 and H2 within the above ranges are not particularly limited, but examples include blending a polyhydroxyalkanoic acid resin with a crystalline polylactic acid resin and an amorphous polylactic acid resin and / or a plasticizer for the polylactic acid resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid, as described below, creating a difference in MFR (melt flow rate, 210°C, 2.16 kg) between the crystalline polylactic acid resin and the amorphous polylactic acid resin and / or a plasticizer for the polylactic acid resin, employing the above method while lowering the temperature in the supply section of the extruder cylinder and raising the temperature in the compression section during film formation, and employing the above method while performing heat treatment and relaxation treatment after biaxial stretching.

[0024] The film of the present invention has at least one peak of loss tangent in the range of more than -30°C but less than 30°C and in the range of 40°C or more and 100°C or less, and when the maximum peak of loss tangent in the range of more than -30°C but less than 30°C is tan δ(A) and the maximum peak of loss tangent in the range of 40°C or more and 100°C or less is tan δ(B), it is preferable that tan δ(A) and tan δ(B) satisfy formula (1).

[0025] 0.8≦tanδ(B) / tanδ(A)≦10...Equation (1) The peak loss tangent in the range of 40°C to 100°C is believed to be due to a resin component with a high glass transition temperature that is favorable when used in combination with an aliphatic polyester. The ratio of the maximum value of tan δ(B) to the tan δ(A) derived from the aliphatic polyester is an index of the uniformity of the amorphous structure and the mixing state of the components in the stretch-oriented film. A film satisfying the above formula (1) indicates that the aliphatic polyester with a glass transition temperature below room temperature, which is excellent in biodegradability, and the aliphatic polyester with a high glass transition temperature, which is excellent in heat resistance, are phase-separated and uniformly present in an appropriate range. Films with such a structure facilitate efficient biodegradation. From this perspective, the tan δ(B) / tan δ(A) ratio is preferably 1.0 to 8.0, more preferably 1.2 to 4.0, and particularly preferably 1.5 to 2.5. The method for controlling tan δ(B) / tan δ(A) within a preferred range is not particularly limited, but examples include blending a crystalline polylactic acid resin and an amorphous polylactic acid resin and / or a plasticizer for polylactic acid resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid, as described below, or creating a difference in MFR between the crystalline polylactic acid resin and the amorphous polylactic acid resin and / or a plasticizer for polylactic acid resin, or employing the above method while keeping the temperature of the supply section of the extruder cylinder low and the compression section high during film production, or employing the above method while setting the areal stretching ratio in biaxial stretching to 2.3 times or more.

[0026] The film of the present invention preferably has a loss tangent (tan δ(60)) at 60°C of 0.10 or more. Tan δ(60) is believed to be derived from the amorphous structure of the resin in the film of the present invention, which has a glass transition temperature higher than that of the polyhydroxyalkanoic acid. Tan δ(60) indicates the mobility of amorphous molecular chains in the film in an environment around 60°C. This allows the film to adapt to fluctuations in conveying tension with adequate flexibility in environments where the film is exposed to temperatures above 60°C, such as when processed into packaging bags, thereby suppressing breakage and providing excellent processability. From the above perspective, tan δ(60) is preferably 0.15 or more, more preferably 0.20 or more. On the other hand, if tan δ(60) is too large, the film may become too flexible and lack strength in environments where the film is exposed to temperatures above 60°C. This can lead to excessive stretching and wrinkles due to the conveying tension between rolls, especially when the film is used as a packaging bag. Therefore, tan δ(60) is preferably 0.5 or less, more preferably 0.45 or less, and even more preferably 0.40 or less. The method for controlling tan δ(60) within the above range is not particularly limited, but examples include a method of blending a polyhydroxyalkanoic acid resin with a polylactic acid-based resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid, as described below, or a method of employing the above method while setting the areal stretching ratio in biaxial stretching to 2.3 times or more.

[0027] In the film of the present invention, when a wide-angle X-ray diffraction analysis is performed in the thickness direction using CuKα radiation, the crystallite size calculated from the half-width of PB is preferably 5 nm to 60 nm, where PB is the most intense peak among peaks with an orientation degree of 0.50 or more within a diffraction angle 2θ range of 19° to 21°. The diffraction peak is derived from the crystalline structure of polyhydroxyalkanoic acid, which contributes to the strength, flexibility, and biodegradability of the film. An orientation degree of 0.50 or more results in a highly biodegradable crystalline structure within the film, while the orientation of the crystalline structure is high in the in-plane direction, making them less likely to become the starting point for breakage upon impact and improving the flexibility of the film. By setting the crystallite size of crystals with such an orientation degree to 5 nm or more, the film can have a highly biodegradable and sufficiently oriented crystalline structure, thereby increasing the film's breaking strength. Additionally, when the film is used for applications such as packaging or agriculture, forestry, and fisheries, sagging during vapor deposition processing and transportation, which can occur, can be suppressed, thereby preventing the film from breaking under tension. Furthermore, by setting the crystallite size to 60 nm or less, the crystalline structure can be maintained without excessive growth during the manufacturing process, thereby preventing a decrease in film strength. Additionally, when the film is used for packaging applications or agricultural, forestry, and fisheries applications, for example, the film can be prevented from being deformed excessively, and deterioration in properties caused by cracking or cleavage of the functional layer, such as vapor deposition, can be reduced. Furthermore, biodegradability can also be improved. From the above viewpoints, the crystallite size is more preferably 7 nm or more, even more preferably 9 nm or more, and particularly preferably 11 nm or more. From the above viewpoints, the crystallite size is more preferably 50 nm or less, even more preferably 40 nm or less, and even more preferably 30 nm or less. Measurement by wide-angle X-ray diffraction in the thickness direction using CuKα radiation is performed according to the method described in the Examples.The method for controlling the crystallite size within the above range is not particularly limited, but examples include, as described below, a method of adjusting the blend content of the polyhydroxyalkanoic acid resin and the polylactic acid resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid while employing the above method, a method of lowering the temperature in the feed section of the extruder cylinder and raising the temperature in the compression section during film formation, and a method of employing the above method while setting the areal stretching ratio in biaxial stretching to 2.3 times or more. If the stretching ratio is lower than the above, the crystal size may remain coarse after film formation. Furthermore, crystal growth can be controlled by heat treatment at 100 ° C or higher but below the melting point of the polyhydroxyalkanoic acid after biaxial stretching. Furthermore, if the heat treatment temperature is lower than the above range, crystal growth may be insufficient, and if it is higher than the above range, only grown coarse crystals may remain.

[0028] Furthermore, from the viewpoint of preventing a decrease in strength due to excessive orientation of the crystals, the degree of orientation is more preferably 0.99 or less. From the above viewpoints, the degree of orientation is more preferably 0.75 or more, even more preferably 0.90 or more, and particularly preferably 0.95 or more. From the above viewpoints, the degree of orientation is more preferably 0.98 or less, and particularly preferably 0.97 or less. Note that, from the viewpoint of appropriately measuring a film with a high degree of orientation in the planar direction, when determining the degree of crystal orientation using the method described in the Examples, it is preferable that the peak position with the highest intensity in the orientation profile (hereinafter sometimes referred to as the orientation angle) appears within a circular angle of 90°±10°. The method for controlling the degree of orientation within the above range is not particularly limited, but examples include, as described below, a method of employing the above method while adjusting the content of the polyhydroxyalkanoic acid resin blended with the polylactic acid-based resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid; a method of lowering the temperature in the supply section of the extruder cylinder and raising the temperature in the compression section during film formation; and a method of employing the above method while achieving an areal stretching ratio of 2.3 times or more in biaxial stretching. If the stretching ratio is lower than the above, the resulting film may have insufficient crystal orientation. Furthermore, by heat treating the film after biaxial stretching at a temperature above 100°C and below the melting point of the polyhydroxyalkanoic acid, the molecular chains that have been highly oriented by stretching can be fixed and a stable structure can be obtained.

[0029] In the film of the present invention, when the breaking strength in the longitudinal direction is S1 (MPa) and the breaking strength in the width direction is S2 (MPa), it is preferable that both S1 and S2 are 30 MPa or more and 280 MPa or less. By making both S1 and S2 30 MPa or more, it is possible to suppress a decrease in processability caused by excessively high flexibility of the film. Furthermore, by making both S1 and S2 280 MPa or less, it is possible to suppress a decrease in processability caused by excessively high rigidity of the film. From the above viewpoints, it is more preferable that both S1 and S2 are 35 MPa or more and 240 MPa or less, and even more preferable that they are 40 MPa or more and 200 MPa or less. There are no particular limitations on the method for controlling S1 and S2 within the above ranges, but examples include a method of blending a polyhydroxyalkanoic acid resin with a crystalline polylactic acid resin and an amorphous polylactic acid resin and / or a plasticizer for polylactic acid resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid, as described below; a method of employing the above method while keeping the temperature of the supply section of the extruder cylinder low and the compression section high during film production; a method of employing the above method while setting the areal stretching ratio in biaxial stretching to 2.3 times or more; and a method of employing the above method while performing heat treatment and relaxation treatment after biaxial stretching.

[0030] In the film of the present invention, when the breaking elongation in the longitudinal direction is L1 (%) and the breaking elongation in the transverse direction is L2 (%), it is preferable that both L1 and L2 are 10% or more and 350% or less. By making both L1 and L2 10% or more, it is possible to suppress a decrease in processability caused by excessively low toughness and flexibility of the film. Furthermore, by making both L1 and L2 350% or less, it is possible to suppress a decrease in processability caused by excessively high flexibility of the film. From the above viewpoints, it is more preferable that both L1 and L2 are 50% or more and 330% or less, and even more preferable that they are 120% or more and 300% or less. The method for controlling L1 and L2 within the above ranges is not particularly limited, but examples include a method of blending a polyhydroxyalkanoic acid resin with a crystalline polylactic acid resin and an amorphous polylactic acid resin and / or a plasticizer for polylactic acid resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid, as described below; a method of employing the above method while keeping the temperature of the supply section of the extruder cylinder low and the compression section high during film production; a method of employing the above method while setting the areal stretching ratio in biaxial stretching to 2.3 times or more; and a method of employing the above method while performing heat treatment and relaxation treatment after biaxial stretching.

[0031] The film of the present invention preferably contains polyhydroxyalkanoic acid as the aliphatic polyester, and the polyhydroxyalkanoic acid content is preferably 45% by mass or more relative to the total mass of the film (100% by mass). From the viewpoints of quietness and good compostability at room temperature and biodegradability in the ocean, the content is more preferably 55% by mass or more, and even more preferably 65% ​​by mass or more. There is no particular upper limit, but it is generally 99% by mass.

[0032] Furthermore, when the film of the present invention is a laminate film, the X layer containing the aliphatic polyester preferably contains polyhydroxyalkanoic acid, and the polyhydroxyalkanoic acid content is preferably 45% by mass or more relative to 100% by mass of the total mass of the X layer containing polyhydroxyalkanoic acid.

[0033] The films of the present invention contain a polyhydroxyalkanoic acid component as an aliphatic polyester having a glass transition temperature below room temperature and a biodegradable resin component having excellent heat resistance in appropriate ranges, thereby enabling control of tan δ, heat shrinkage, breaking elongation, and breaking strength, thereby achieving biodegradability, processability, quietness, and barrier properties. Specifically, from the viewpoint of increasing the affinity between resins and achieving processability and barrier properties, it is preferable to select a biodegradable aliphatic polyester other than polyhydroxyalkanoic acid as the biodegradable resin component having excellent heat resistance. Specific examples of biodegradable aliphatic polyesters other than polyhydroxyalkanoic acid include polyglycolic acid, polylactic acid, polyethylene succinate, polybutylene succinate, and polybutylene succinate adipate. It is more preferable to select a biodegradable resin having a higher glass transition temperature or melting point than the polyhydroxyalkanoic acid, the main component. Polylactic acid is particularly preferable from the viewpoint of selecting a resin having both a high glass transition temperature and a high melting point.

[0034] When the film of the present invention contains polylactic acid, it is preferable to mix a crystalline polylactic acid resin with an amorphous polylactic acid resin and / or a plasticizer for polylactic acid resin from the viewpoints of improving biodegradability, processability, quietness, and barrier properties. The crystalline polylactic acid resin increases the mechanical properties of the film, such as breaking strength and elastic modulus, thereby contributing to improved film processability, while the amorphous polylactic acid resin and / or plasticizer for polylactic acid resin enhances molecular mobility, thereby contributing to improved quietness and biodegradability. When the film of the present invention contains polylactic acid, with regard to the content ratio of the crystalline polylactic acid resin to the amorphous polylactic acid resin and / or plasticizer for polylactic acid resin, it is preferable that the amorphous polylactic acid resin and / or plasticizer for polylactic acid resin is contained in a greater amount than the crystalline polylactic acid, from the viewpoint of easily achieving the effects of film formability, quietness, and biodegradability. The crystalline polylactic acid resin in the present invention is a resin that exhibits a melting point when heated from -50°C to 200°C at a heating rate of 20°C / min according to JIS K7121-1987 and JIS K7122-1987 at a rate of 20°C / min, and has a crystalline heat of fusion / Hm of 3.0 J / g or more calculated from the melting peak. The amorphous polylactic acid resin in the present invention is a resin that exhibits no melting peak when heated from -50°C to 200°C at a heating rate of 20°C / min according to JIS K7121-1987 and JIS K7122-1987 at a rate of 20°C / min, or, if a melting peak is observed, has a crystalline heat of fusion / Hm of less than 3.0 J / g calculated from the melting peak.

[0035] In the film of the present invention, the content of the crystalline polylactic acid resin is preferably 1% to 45% by mass, more preferably 5% to 40% by mass, and even more preferably 10% to 35% by mass, based on the total mass of the film (100% by mass). Furthermore, the content of the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin is preferably 1% to 45% by mass, more preferably 5% to 40% by mass, and even more preferably 10% to 35% by mass, based on the total mass of the film (100% by mass). The absolute value of the difference between the content (% by mass) of the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin minus the content (% by mass) of the crystalline polylactic acid resin is preferably 0 to 44, more preferably 0 to 30, and even more preferably 0 to 20.

[0036] The plasticizer for polylactic acid resin of the present invention is an additive that penetrates into the gaps of polylactic acid resin, thereby inhibiting the regular orientation of the polylactic acid resin, lowering the glass transition temperature of the polylactic acid resin, or increasing the portion of the polylactic acid resin that remains amorphous even below the glass transition temperature, thereby improving the flexibility and impact resistance of the polylactic acid resin. The plasticizer for polylactic acid resin of the present invention may be any known material that has a plasticizing effect on polylactic acid resin. Examples of the plasticizer for polylactic acid resin include low-molecular-weight plasticizers and polymeric plasticizers. Low-molecular-weight plasticizers are preferred from the viewpoint of excellent compatibility with polylactic acid resin and further enhancing molecular mobility, while polymeric plasticizers are preferred from the viewpoint of suitability for high-temperature melt extrusion processing. These plasticizers can be used alone or in combination of two or more.

[0037] Low molecular weight plasticizers include fatty acid esters, hydroxy acid esters, aromatic dicarboxylic acid esters, and aliphatic dicarboxylic acid esters. They may be produced by either chemical synthesis or natural synthesis, but low molecular weight plasticizers produced by chemical synthesis are preferred from the viewpoint of suitability for melt extrusion processing.

[0038] Specific examples of fatty acid esters include glycerin fatty acid esters, sorbitan fatty acid esters, methyl oleate esters, butyl stearate esters, and isopropyl myristate esters. Examples of hydroxy acid esters include various citrate esters such as acetyl tributyl citrate, tributyl citrate, and triethyl citrate esters. Examples of aromatic dicarboxylic acid esters include dimethyl terephthalate, dibutyl terephthalate, dimethyl isophthalate, diethyl phthalate, dioctyl phthalate, and diisononyl phthalate. Examples of aliphatic dicarboxylic acid esters include dioctyl sebacate, dibutyl sebacate, diisononyl glutarate, di(2-ethylhexyl) adipate, diisononyl adipate, dioctyl adipate, dibutyl adipate, and various other dibasic acid esters (including mixed-group dibasic acid esters).

[0039] Among these, fatty acid esters and aliphatic dicarboxylic acid esters are preferred from the viewpoint of improving biodegradability and noise reduction.

[0040] Examples of polymer plasticizers include polyether polymers, polyester polymers, polyvinyl polymers, and polyol polymers, which may be homopolymers, random copolymers, block copolymers, or graft copolymers with polylactic acid resins, or polymer derivatives having a modifying group at the end.

[0041] Specifically, examples of polyether polymers include polyethylene glycol and polypropylene glycol. Examples of polyester polymers include polycaprolactone, polybutylene succinate, polybutylene adipate terephthalate, and polybutylene succinate adipate. Examples of polyvinyl polymers include polyvinyl alcohol and polyvinyl acetate. Examples of polyol polymers include polyoxypropylene diol and polyoxyethylene diol.

[0042] Among these, polyethylene glycol is preferred from the viewpoint that the polymer plasticizer itself has excellent biodegradability, and from the viewpoint of achieving ease of handling during melt extrusion processing, it is more preferable that the number average molecular weight of polyethylene glycol is 2000 or more and 9500 or less.

[0043] Furthermore, when the film of the present invention is a laminate film, the X layer containing the aliphatic polyester preferably contains a crystalline polylactic acid resin and an amorphous polylactic acid resin and / or a plasticizer for the polylactic acid resin, and the content of the crystalline polylactic acid resin in the X layer is preferably 1% to 45% by mass, more preferably 5% to 40% by mass, and even more preferably 10% to 35% by mass, based on the total mass of the X layer containing the aliphatic polyester (100%). Furthermore, the content of the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin in the X layer is preferably 1% to 45% by mass, more preferably 5% to 40% by mass, and even more preferably 10% to 35% by mass, based on the total mass of the X layer containing the aliphatic polyester (100%).

[0044] Increasing the MFR of the highly crystalline polylactic acid resin relative to the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin reduces the viscosity difference between the highly crystalline polylactic acid resin and the polyhydroxyalkanoic acid, which is preferable from the perspective of improving the dispersibility of the crystalline polylactic acid resin and controlling the thermal shrinkage and mechanical properties. Increasing the viscosity difference between the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin and the polyhydroxyalkanoic acid increases the domain size of the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin, making it easier to achieve quieter operation and biodegradability for home composting. The ratio of the MFR of the crystalline polylactic acid resin to the MFR of the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin is preferably 0.5 times or more, more preferably 1.2 times or more, even more preferably 1.7 times or more, and particularly preferably 2.0 times or more. The upper limit is not particularly limited, but is set to 10 times in consideration of the kneadability of polyhydroxyalkanoic acid and polylactic acid resins.

[0045] The film of the present invention may contain resins other than polyhydroxyalkanoic acid and polylactic acid, and various additives such as organic particles, inorganic particles, antioxidants, heat stabilizers, slipping agents, antistatic agents, antiblocking agents, fillers, viscosity modifiers, and color inhibitors, as long as the object of the present invention is not impaired.

[0046] The film of the present invention can be used for a wide variety of purposes, including packaging applications, release applications, and as packaging materials, packing materials, sanitary products, agricultural, forestry, and fishery products (agricultural, forestry, and fishery materials), construction products, medical products, and process films for manufacturing various products.For example, when used for packaging applications, the film is a good film that is excellent in quietness and does not break or deform even under the conveying tension in processing and vapor deposition processes, and because it is biodegradable, it can be suitably used as a film for agriculture, forestry, and fisheries.

[0047] The thickness of the film of the present invention can be set depending on the application, but for example, for applications in sheet form such as general packaging, release agents, and agricultural, forestry, and fisheries applications, it is preferably 6 μm or more and 200 μm or less, and from the viewpoint of handling during processing and use, the upper limit is more preferably 100 μm, even more preferably 50 μm, and the lower limit is more preferably 8 μm, even more preferably 10 μm. Furthermore, for applications including a molding process such as tray molding or applications requiring self-supporting properties, from the viewpoint of processability and handleability, it is preferably 10 μm or more and 300 μm or less, and from the viewpoint of cost and film formability, the upper limit is more preferably 250 μm, even more preferably 220 μm, and the lower limit is more preferably 30 μm, even more preferably 50 μm.

[0048] <Film with functional layer> The film of the present invention is preferably provided with a functional layer depending on the application, and may have a functional layer on at least one side. Hereinafter, a film having a functional layer will be described. The film of the present invention provided with a functional layer may be simply referred to as a "laminate." Examples of functional layers that can be laminated on the film include a gas barrier layer, an adhesive layer, a heat-sealing layer, an easy-adhesion layer, a colored layer, a printed layer, an easy-peel layer, a release layer, an easy-slip layer, a porous layer, and a nonwoven fabric. The lamination method for the functional layer may be selected depending on the functional layer, and may be, for example, deposition, sputtering, coating, various printing methods such as gravure printing and offset printing, thermal adhesion, lamination via an adhesive layer, or the like. From the viewpoint of not impairing the effects of the present invention, it is preferable that the functional layer be biodegradable or have low toxicity. For example, when used for packaging applications or agriculture, forestry, and fisheries, a gas barrier coating layer or a vapor deposition layer is preferably provided from the viewpoint of imparting gas barrier properties, and a vapor deposition layer is more preferable from the viewpoint of exhibiting high gas barrier performance. In addition, from the viewpoint of imparting heat-sealing properties, it is preferable to provide a heat-sealing resin layer or coating layer, and when multiple films are laminated, a coating layer is more preferable from the viewpoint of reducing the thickness of the final product. When the film of the present invention is used to cover agricultural, forestry and fishery materials such as fertilizers, feeds, seeds and seedlings, and medicines, an adhesive layer that imparts pressure-bonding properties or a heat-sealing layer that imparts thermocompression-bonding properties is preferable as a functional layer that imparts adhesiveness.

[0049] When a vapor-deposited layer is laminated as a functional layer on the film of the present invention, the vapor-deposited layer is preferably laminated on at least one side of the film. Furthermore, from the viewpoint of gas barrier property, the vapor-deposited layer is preferably a layer containing more than 50% by mass but not more than 100% by mass of a metal and an inorganic compound (hereinafter, sometimes referred to as "Layer D"). Here, "a layer containing more than 50% by mass but not more than 100% by mass of a metal and an inorganic compound" refers to a layer containing more than 50% by mass of a metal alone, a layer containing more than 50% by mass of an inorganic compound alone, or a layer containing both a metal and an inorganic compound, the total of which exceeds 50% by mass, when the total of all components constituting the vapor-deposited layer is taken as 100% by mass. As the metal and / or inorganic compound that can be used in Layer D, from the viewpoints of improving adhesion to the film, improving gas barrier property when laminated on the film, and reducing environmental impact, for example, aluminum, aluminum oxide, silicon oxide, germanium oxide, magnesium oxide, cerium oxide, calcium oxide, diamond-like carbon film, or a mixture thereof is preferably used. Furthermore, from the viewpoint of the visibility of the contents, it is more preferable to use an inorganic compound, particularly aluminum oxide, silicon oxide, or a mixture containing these. The thickness of the D layer in the laminate is preferably 200 nm or less from the viewpoints of recyclability when the laminate is reused as a resin or film, suppressing deterioration of gas barrier properties due to cracks, and obtaining visibility of the contents when used as a packaging material. From the above viewpoints, it is more preferably 110 nm or less, even more preferably 50 nm or less, and even more preferably 30 nm or less. The lower limit is not particularly limited, but is set to 1 nm from the viewpoint of exhibiting barrier properties.

[0050] Furthermore, in the laminate of the present invention, a resin layer having a thickness of 1 μm or less may be provided between the D layer and the film surface by coating or the like. The provision of such a resin layer may have the effect of improving the adhesion between the D layer and the film. However, from the viewpoint of production costs, an embodiment without such a resin layer (i.e., an embodiment in which the D layer is directly laminated on the outermost surface of the film) is preferred, and an embodiment in which the D layer is on the surface of the film is more preferred.

[0051] Methods for forming a D layer on the film of the present invention to form a laminate include coating, vapor deposition, lamination, etc., but vapor deposition is particularly preferred because it is independent of humidity and can exhibit excellent gas barrier properties even in a thin film. Vacuum deposition methods include physical vapor deposition methods such as vacuum deposition, EB vapor deposition, sputtering, and ion plating, and various chemical vapor deposition methods such as plasma CVD, but vacuum deposition is particularly preferred from the viewpoint of productivity.

[0052] In the laminate of the present invention, an overcoat layer may be provided on the surface of Layer D facing the aliphatic polyester film, from the viewpoint of improving the gas barrier property and suppressing a decrease in the gas barrier property due to deposition defects or cracks in Layer D.

[0053] When a functional layer such as an adhesive layer or a heat seal layer that provides adhesiveness (hereinafter sometimes referred to as "layer E") is laminated on the aliphatic polyester film of the present invention, it is preferable that it be laminated on at least one side of the film. Resin components that can be used in Layer E include, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-methacrylic acid copolymer, etc., or mixtures thereof, which have high heat seal strength. When multiple films are laminated, for example, ethylene-vinyl acetate copolymer (EVA)-based hot melt adhesives, olefin-based hot melt adhesives, rubber-based hot melt adhesives, polyester-based hot melt adhesives, polyamide-based hot melt adhesives, polyurethane-based hot melt adhesives, etc., or mixtures thereof, which have low thickness, are suitable. For example, resin components prepared by adjusting the copolymerization component of the polyhydroxyalkanoic acid exemplified above, or biodegradable resins with a lower softening point or melting point than the aliphatic polyester film of the present invention, such as polylactic acid, polyglycolic acid, and polybutylene succinate, or mixtures thereof, which have low heat seal strength, are suitable.

[0054] The thickness of Layer E in the laminate is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 3 μm or more, from the viewpoint of exhibiting high adhesive strength, and is preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less, from the viewpoint of preventing a decrease in the biodegradability of the laminate and of reducing the thickness of the final product when multiple films are laminated.

[0055] Furthermore, in the laminate, a resin layer having a thickness of 1 μm or less may be provided between the E layer and the surface of the aliphatic polyester film by coating or the like. The provision of such a resin layer may have the effect of improving the adhesion between the E layer and the aliphatic polyester film. However, from the viewpoint of production costs, an embodiment without such a resin layer (i.e., an embodiment in which the E layer is directly laminated on the outermost surface of the aliphatic polyester film) is preferred, and an embodiment in which the E layer is provided on the surface of the aliphatic polyester film is more preferred.

[0056] As a method for forming the E layer on the aliphatic polyester film to form a laminate, coating or lamination is particularly preferred. As a coating method, a bar coating method, a gravure coating method, a calendar coating method, a die coating method, etc. can be used. As a lamination method, a dry lamination method, a solventless lamination method, an extrusion lamination method, a coextrusion method, etc. can be used. From the viewpoint of productivity, the gravure coating method, the die coating method, the extrusion lamination method, and the coextrusion method are more preferably used.

[0057] When laminating a Y layer and a heat-sealable layer (E layer) as a functional layer to the film of the present invention, it is preferable that the heat-sealable layer is laminated on at least one side of the film. Furthermore, from the viewpoint of achieving both biodegradability and processability of the film, it is preferable that the heat-sealable layer be a layer that fuses at a temperature of 100°C or higher and 20°C or lower than the melting point of the film of the present invention. Here, "a layer that fuses at a temperature of 100°C or higher and 20°C or lower than the melting point of the film of the present invention" means that the main component of the heat-sealable layer is a resin component that has a softening point or melting point of 100°C or higher and 20°C or lower than the melting point of the film of the present invention. Resin components that can be used in the heat seal layer, from the viewpoint of having high heat seal strength, are preferably, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-methacrylic acid copolymer, etc., or mixtures thereof. When multiple films are laminated, from the viewpoint of reducing the thickness of the final product, are preferably, for example, ethylene-vinyl acetate copolymer (EVA)-based hot melt adhesives, olefin-based hot melt adhesives, rubber-based hot melt adhesives, polyester-based hot melt adhesives, polyamide-based hot melt adhesives, polyurethane-based hot melt adhesives, etc., or mixtures thereof. From the viewpoint of improving the biodegradability of the entire laminate, are preferably, for example, resin components containing a copolymer component of polyhydroxyalkanoic acid as the aliphatic polyester exemplified above, or biodegradable resins having a softening point or melting point 20°C or more lower than that of the film of the present invention, such as polylactic acid, polyglycolic acid, polybutylene succinate, etc., or mixtures thereof.

[0058] The thickness of the heat seal layer (layer E) in the laminate film and laminate is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more, from the viewpoints of achieving high heat seal strength and biodegradability, and is preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less, from the viewpoints of preventing a decrease in the biodegradability of the laminate and of reducing the thickness of the final product when multiple films are laminated.

[0059] <Packaging materials, packaging> The packaging material and package of the present invention will be described below. The packaging material of the present invention has good gas barrier properties and does not break or deform even under the conveying tension of the vapor deposition process of the vapor deposition layer provided as a gas barrier layer, making it suitable for use in packaging items that are susceptible to deterioration by water vapor or oxygen. Furthermore, because it has excellent flexibility, it is suitable for use in packaging snacks and other packaging applications, as it reduces noise when touched or folded and is therefore quiet.

[0060] The package of the present invention is characterized in that the contents are packaged in the packaging material of the present invention. The contents are not particularly limited, but since the packaging material of the present invention has excellent transparency and gas barrier properties, it is preferable that the contents be visible from the outside and be easily deteriorated by water vapor or oxygen. The package of the present invention can be obtained by covering the contents with the packaging material of the present invention, and the form thereof is not particularly limited. For example, a package obtained by processing the packaging material of the present invention into a bag shape by heat sealing and placing the contents inside, or a package obtained by filling or placing the contents in a tray-shaped container and then sealing it with the packaging material of the present invention, etc., can be mentioned.

[0061] <Agriculture, forestry and fisheries materials> The agricultural, forestry and fishery material of the present invention will be described below. The agricultural, forestry and fishery material of the present invention is characterized by using at least one of the film of the present invention and the laminated film of the present invention. The agricultural, forestry and fishery material of the present invention is characterized by being biodegradable, and is suitable for use as materials that biodegrade after use, such as soil mulch films, vegetation films, fumigation films, water retention films, fertilizer coating materials, feed coating materials, seed and seedling coating materials, pesticide coating materials, aquaculture support films, films for inhibiting the adhesion of marine organisms, and environmental conservation materials.

[0062] <Covering film for agricultural, forestry and fishery materials> The aliphatic polyester film of the present invention can be used to cover agricultural, forestry, and fishery materials containing one or more selected from fertilizers, feed, seeds, and chemicals, protecting the covered agricultural, forestry, and fishery materials and preventing quality deterioration due to degradation and environmental pollution due to leakage, while biodegrading in soil or the ocean, allowing the fertilizer, feed, or chemical to diffuse and disperse at an appropriate time, protecting the seeds and seedlings from settling and settling in bed, and then biodegrading to prevent interference with their growth. The agricultural, forestry, and fishery materials referred to here refer to materials and components contained in agricultural, forestry, and fishery materials, and are not particularly limited as long as they do not impair the effects of the present invention, but a wide variety of known materials can be used.

[0063] As described above, the aliphatic polyester film of the present invention, which has excellent biodegradability and moderate processability, can be used for this purpose to prevent leakage of the agricultural, forestry, and fishery materials contained therein through pinholes, cracks, and uneven coating thickness. The thickness of the aliphatic polyester film of the present invention can also control the diffusion and dispersion rate in soil and ocean. In addition, two or more agricultural, forestry, and fishery materials, such as fertilizers, feeds, seeds, and chemicals, can be coated together. For example, coating seeds and seedlings with the desired fertilizers or chemicals together is preferable because it can enhance crop growth simultaneously with germination.

[0064] From the above viewpoint, the thickness of the aliphatic polyester film is preferably selected within the above-mentioned preferred range according to the diffusion and scattering speed in the soil or ocean. If the thickness of the aliphatic polyester film is too thin, the strength may be insufficient, which may reduce the protection of the contents or cause tearing during processing. Furthermore, if the thickness of the aliphatic polyester film is too thick, the flexibility may be insufficient, which may make it difficult to process into the desired shape described below. For example, by selecting a thin film for fast-acting fertilizers that will diffuse and scatter quickly after biodegradation and a thick film for slow-acting fertilizers that will diffuse and scatter slowly after biodegradation, and spreading these coated fertilizers together, the work of farmers can be reduced.

[0065] Furthermore, by taking advantage of the characteristics of the aliphatic polyester film of the present invention, the coating can be made into a multilayer structure. Specifically, by coating a slow-release fertilizer with the aliphatic polyester film of the present invention and then coating the surrounding area with a fast-release fertilizer and the aliphatic polyester film of the present invention, it is possible to produce a fertilizer in which the slow-release fertilizer and the fast-release fertilizer are sequentially coated with the aliphatic polyester film of the present invention. Furthermore, by coating seeds and seedlings with fertilizer, feed, and chemicals in that order in a similar manner, it is expected that the fertilizer, feed, and chemicals will be applied to the grown agricultural and marine products at the appropriate time.

[0066] As described above, the fertilizers, feeds, seeds, and chemicals coated with the aliphatic polyester film of the present invention can enhance the effectiveness of agricultural, forestry, and fishery materials selected from fertilizers, feeds, seeds, and chemicals while preventing environmental pollution due to unintended leakage. By diffusing and scattering in the soil or ocean at the appropriate time, the efficacy can be improved and the workload of workers can be reduced, making the film particularly suitable for use in the agriculture, forestry, and fisheries fields.

[0067] The form of the fertilizer, feed, seeds and chemicals coated with the aliphatic polyester film of the present invention is not particularly limited as long as it does not impair the effects of the present invention, and various forms such as pellets, granules, blocks, pouches, ropes, sheets, etc. Specifically, for coated fertilizers for agricultural use, block, pellet or granular forms that are compatible with spreaders are preferred, while for coated seeds and chemicals, rope or sheet forms that are expected to reduce work are preferred.

[0068] <Manufacturing method> A preferred embodiment of the film production method of the present invention will be described below.

[0069] The method for producing a film of the present invention involves, in this order, a melting step in which an aliphatic polyester is melted, a casting step in which the melted polyester is extruded into a sheet form from a die and cooled and solidified on a support to obtain an aliphatic polyester sheet, a stretching step in which the aliphatic polyester sheet is stretched in two perpendicular directions, and a heat treatment step in which the film obtained in the stretching step is subjected to a heat treatment and relaxation treatment. The aliphatic polyester film of the present invention is not particularly limited in terms of layer structure, and can employ, for example, a two-type two-layer structure (Y layer / X layer), a two-type three-layer structure (Y layer / X layer / Y layer), or a three-type three-layer structure (Y layer / X layer / Z layer) (here, Z layer refers to a layer different from the X layer and Y layer). Below, the production method will be described in more detail using, as an example, a film with an X layer as an aliphatic polyester film having a single-layer structure consisting of an X layer, in which the X layer is made of a polyhydroxyalkanoic acid; however, the film of the present invention and its production method should not be construed as necessarily being limited thereto.

[0070] First, to achieve good biodegradability, processability, quietness, and barrier properties, polyhydroxyalkanoic acid (a type of aliphatic polyester) is blended with polylactic acid (a type of biodegradable resin with a higher glass transition temperature or melting point than polyhydroxyalkanoic acid). The blend is then kneaded and mixed in a single-screw extruder set to a multi-stage temperature configuration: a feed zone temperature of 150°C, a compression zone temperature of 170-220°C, and a metering zone temperature above the compression zone to 220°C. The resulting melt is then extruded through a filtration filter to remove impurities. The molten resin is then extruded through a slit-shaped nozzle. Furthermore, blending polylactic acid with amorphous polylactic acid resin and / or a plasticizer for polylactic acid resin with crystalline polylactic acid resin is preferred, as this facilitates control of tan δ(30) and mechanical properties.

[0071] Furthermore, a high MFR (2.16 kg at 210°C) of the highly crystalline polylactic acid resin relative to the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin is preferable from the viewpoint of reducing the viscosity difference between the highly crystalline polylactic acid resin and the polyhydroxyalkanoic acid, improving the dispersibility of the crystalline polylactic acid resin, and controlling the thermal shrinkage and mechanical properties. A larger viscosity difference between the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin and the polyhydroxyalkanoic acid results in a larger domain of the amorphous polylactic acid resin and / or the plasticizer for the polylactic acid resin, making it easier to achieve quieter operation and biodegradability for home composting. The difference in MFR between the highly crystalline polylactic acid resin and the amorphous polylactic acid resin and the plasticizer for the polylactic acid resin is preferably 1.1 times or more, more preferably 1.4 times or more, even more preferably 1.7 times or more, and particularly preferably 2.0 times or more.

[0072] Next, the molten resin sheet extruded from the slit die is cooled and solidified on a casting drum whose surface temperature is controlled to 10° C. to 40° C. to obtain an unstretched film. The molten resin sheet may be adhered to the casting drum by any of the following methods: electrostatic application, adhesion using the surface tension of water, air knife method, press roll method, underwater casting method, air chamber method, etc., or a combination of two or more methods may be used.

[0073] Next, the breaking strength, loss tangent, and crystallite size of the film of the present invention can be controlled by molecular orientation through stretching. As for the stretching method, sequential biaxial stretching, in which stretching is performed separately in the longitudinal and transverse directions, simultaneous biaxial stretching, and a process in which additional stretching is performed after stretching are preferred. These methods may be performed continuously or individually in a batch system. In the present invention, sequential biaxial stretching is more preferred from the viewpoint of high-speed film formation. In sequential biaxial stretching, a uniaxially oriented film is first obtained in a longitudinal stretching process. In the longitudinal stretching process, the unstretched film is first preheated using a group of multiple rolls heated to a temperature above the casting drum temperature but not higher than the casting drum temperature + 50°C. If the temperature of the preheating roll group is lower than the casting drum temperature, film rupture due to insufficient temperature may occur. If the temperature of the preheating roll group exceeds the casting drum temperature + 50°C, crystallization may progress, causing uneven stretching and delaying the biodegradation rate. From the above viewpoint, the temperature of the preheating roll group is more preferably the casting drum temperature +10°C or more and 40°C or less, and even more preferably the casting drum temperature +15°C or more and 35°C or less.

[0074] Then, while maintaining the temperature of the preheated sheet, the sheet is stretched in the longitudinal direction at a ratio of 1.5 to 10 times, using the speed difference between the rolls, to obtain a uniaxially oriented (longitudinal stretched) film. If the longitudinal stretching ratio is less than 1.5 times, oriented crystallization may be insufficient, or the constraint structure that improves mechanical properties and heat shrinkage properties may not be sufficiently formed due to the influence of fewer tensed amorphous molecular chains and more relaxed amorphous molecular chains, making it difficult to obtain sufficient strength. If the stretching ratio exceeds 10 times, excessive orientation may occur, making the film more susceptible to rupture. From the above perspectives, the uniaxial stretching ratio is more preferably 2.0 to 7 times, and even more preferably 2.5 to 5 times.

[0075] Next, the film, uniaxially stretched in the longitudinal direction, is introduced into a tenter while the edges of the film are held with clips. While the edges of the film are still held with clips, the film is preheated to a temperature above 50°C and below the melting point of the polyhydroxyalkanoic acid, and then stretched in the width direction (transverse stretching) at a ratio of 1.5 to 10 times. Preheating temperatures below 60°C can result in film rupture due to insufficient temperature. Preheating temperatures above the melting point of the polyhydroxyalkanoic acid can result in insufficient oriented crystallization, which can relax the tension in the amorphous molecular chains and make it difficult to achieve sufficient breaking strength. Furthermore, stretching ratios below 1.5 times in the width direction can result in coarsening of the crystallite size, insufficient oriented crystallization, or a lack of tension in the amorphous molecular chains and an abundance of relaxed amorphous molecular chains, making it difficult to achieve sufficient breaking strength. Stretching ratios above 10 times can result in film rupture. From the above viewpoints, the preheating temperature of the tenter is preferably 55° C. or higher and not higher than the melting point of polyhydroxyalkanoic acid minus 5° C., and even more preferably 60° C. or higher and not higher than the melting point of polyhydroxyalkanoic acid minus 10° C. The biaxial width direction stretching ratio is more preferably 2.0 times or higher and 7 times or lower, and even more preferably 2.5 times or higher and 6 times or lower.

[0076] Subsequent heat treatment and relaxation treatment after biaxial stretching allows for control of tan δ, breaking elongation, breaking strength, thermal shrinkage, and crystallite size. Specifically, it is preferable to heat the sequentially biaxially stretched film, which has been stretched in the longitudinal and width directions, to 100°C or higher and below the melting point of the polyhydroxyalkanoic acid while narrowing the width of the tenter rails to relax the film by 1% or more and 30% or less in the width direction. These treatments are more preferably carried out continuously within the tenter after stretching in the width direction. If the heating temperature during relaxation is lower than 100°C, the structure of the film, which has become more oriented and crystallized after stretching, may not be sufficiently fixed, or the relaxation of the amorphous molecular chains strained by biaxial stretching may be promoted rather than the formation of a restrained structure, making it difficult to achieve sufficient breaking strength. If the heating temperature exceeds the melting point of the polyhydroxyalkanoic acid, the film may sag, resulting in a decrease in breaking elongation and breaking strength, or the film may break. If the relaxation treatment in the width direction is less than 1%, the heat shrinkage may become too large, and if it exceeds 30%, the film may become loose and the breaking elongation and strength may decrease. From the above viewpoints, in the relaxation treatment of the sequentially biaxially stretched film, the heating temperature is preferably 110°C or higher and the melting point of polyhydroxyalkanoic acid minus 10°C or lower, and even more preferably 125°C or higher and the melting point of polyhydroxyalkanoic acid minus 20°C or lower. The relaxation treatment is more preferably 3% or higher and 20% or lower, and even more preferably 5% or higher and 15% or lower.

[0077] The film of the present invention can be obtained by the stretching method exemplified above. Here, the area stretching ratio, combining the longitudinal and transverse directions, is preferably 2.3 times or more and 100 times or less. If the area stretching ratio is less than 2.3 times, oriented crystallization becomes insufficient, and the restraint structure is not sufficiently formed due to the influence of fewer tensed amorphous molecular chains and more relaxed amorphous molecular chains, which may result in poor mechanical properties, heat shrinkage properties, and thickness unevenness. If the area stretching ratio exceeds 100 times, excessive orientation may occur, resulting in an excessively high heat shrinkage rate. From the above viewpoints, the area stretching ratio is more preferably 4.0 times or more and 50 times or less, and even more preferably 6.0 times or more and 25 times or less.

[0078] Then, in a winding process, the edges on both sides of the film in the width direction are slit. When a functional layer is then laminated on the film of the present invention, it is preferable to apply an in-line surface modification treatment or an easy-adhesion coating to the surface that contacts the functional layer in order to increase the peel strength. The film thus obtained can be wound into a roll to obtain the film that constitutes the laminate of the present invention.

[0079] Next, the method for producing fertilizers, feeds, seeds and seedlings, and drugs coated with the aliphatic polyester film of the present invention will be described in more detail using examples, but the present invention is not necessarily limited to these examples.

[0080] In the method for producing the fertilizer coated with the aliphatic polyester film of the present invention, the aliphatic polyester film obtained by the above method is introduced into upper and lower molds each having a pellet-shaped depression, and the film is then adhered to the molds by suction. Next, the fertilizer to be coated is spread on the film in the lower mold, and the upper mold is lowered and heated to bond the upper and lower films together.

[0081] The fertilizer to be coated with the aliphatic polyester film of the present invention may be in the form of pellets, granules, powder, paste, or liquid. Among these, the granules, powder, paste, and liquid forms are preferred from the viewpoints of ease of protection with the film and conformability to the shape of a mold.

[0082] Furthermore, from the viewpoint of adhesiveness, it is preferable to provide the aliphatic polyester film of the present invention with the aforementioned heat seal layer as an adhesive layer (Layer E). In this case, it is more preferable to arrange the film in a mold so that Layer E is located on at least one side of the surface where the films contact each other. Next, the film coated with the fertilizer is removed from the mold, and the excess film-bonded portion is cut and removed to obtain coated fertilizer processed into pellets. Here, the cutting method preferably uses a cutter equipped with a blade. Examples of the cutting method include a batch-type sheet processing method using a mold equipped with a blade, a method in which the film is continuously cut in one direction using a rotary blade to form a rope and then periodically cut in the perpendicular direction, and a method in which the above-mentioned mold is equipped with a blade to perform heat compression bonding and cutting simultaneously.

[0083] Other methods for coating agricultural, forestry, and fishery materials include a method in which two rolls of the aliphatic polyester film of the present invention are prepared and the agricultural, forestry, and fishery material is inserted between them at regular intervals while laminating them; a method in which the agricultural, forestry, and fishery material is held on the film and heated to cause thermal shrinkage, thereby coating; and a method in which the film is reduced pressure to cause shrinkage and coating.

[0084] According to the present invention, the production method can provide fertilizers, feeds, seeds and seedlings, and medicines coated with the aliphatic polyester film of the present invention, which has excellent biodegradability, processability, noise reduction, and barrier properties.

[0085] <Biodegradation method> The film of the present invention, as well as packaging and agricultural, forestry, and fishery materials containing the film of the present invention, can be biodegraded using composting equipment. Examples of composting equipment that can be used include industrial composting, which is heated to or kept at around 60°C to enhance biodegradability, simple composting made by digging holes in the soil, composting containers that are partially or completely buried in the soil, small composting systems such as compost bags, and biological composting systems such as earthworm composting and zoocomposting using flies. When the film of the present invention, packaging, or agricultural, forestry, and fishery materials containing the film of the present invention does not have a functional layer or when the functional layer is a biodegradable or low-toxicity vapor-deposited layer, they can be decomposed by placing them in composting equipment and subjecting them to general processing, such as mixing with decomposition materials such as soil or a microorganism-containing fermentation promoter. Furthermore, when a non-biodegradable functional layer or other layer is used in combination, the functional layer may be peeled off and then placed in composting equipment, or a layer with low environmental toxicity, human toxicity, etc., may be placed in composting equipment even if it is non-biodegradable, and the residue may be collected after the aliphatic polyester film of the present invention is decomposed. Note that the purposes of composting include waste reduction by volume reduction, composting, and biogas generation, and the film, packaging, and agricultural, forestry, and fisheries material of the present invention are suitable for composting equipment for any purpose. [Example]

[0086] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the embodiments shown below. Each item was evaluated by the following methods.

[0087] <Methods for measuring characteristic values ​​and evaluating effects> The methods for measuring the characteristic values ​​and evaluating the effects in the present invention are as follows.

[0088] (1) Film thickness evaluation The film thickness (unit: μm) was measured in an atmosphere of 23° C. and 65% RH using a contact-type high-precision digital length measuring instrument, “Litematic VL50B” manufactured by Mitutoyo Corporation.

[0089] (2) Evaluation of loss tangent (tanδ) (2-1) Obtaining the loss tangent (tanδ)-temperature curve The film was cut into rectangular pieces measuring 25 mm in length and 10 mm in width in the longitudinal and transverse directions, and the samples were set in a dynamic viscoelasticity measuring device "EXSTAR DMS6100" manufactured by Seiko Instruments Inc., with the long side facing the tensile direction. Then, under the conditions shown below, the atmosphere inside the furnace in which the film was set was cooled with liquid nitrogen, and measurements were performed by raising the temperature from -70°C to 160°C, and a loss tangent (tanδ)-temperature curve was obtained using the dynamic viscoelasticity method. <Measurement conditions> Test mode: Tensile mode Chuck distance: 20mm Frequency: 1Hz Distortion amplitude: 10.0μm Gain: 1.5 Heating rate: 5°C / min Figure 1 is an explanatory diagram illustrating a graph of the tan δ-temperature curve of an aliphatic polyester film. In Figure 1, symbol 1 represents the loss tangent tan δ(30) at 30°C, symbol 2 represents the maximum peak of the loss tangent tan δ(A) in the range from -30°C to less than 30°C, symbol 3 represents the maximum peak of the loss tangent tan δ(B) in the range from 40°C to 100°C, and symbol 4 represents the loss tangent tan δ(60) at 60°C.

[0090] (2-2) tanδ(30) and tanδ(60) From the loss tangent (tanδ)-temperature curve obtained in (2-1), the loss tangent tanδ at 30°C and the loss tangent tanδ at 60°C were determined. Note that, for the present invention, tanδ(30) and tanδ(60) were measured three times in the longitudinal direction and the width direction, and the average values ​​of tanδ(30) and tanδ(60) for a total of six measurements were used.

[0091] (2-3)tanδ(B) / tanδ(A) From the loss tangent (tan δ)-temperature curve obtained in (2-1), the maximum peak of the loss tangent in the range of more than -30°C but less than 30°C was determined as tan δ(A), and the maximum peak of the loss tangent in the range of 40°C or more but less than 100°C was determined as tan δ(B). For the present invention, tan δ(B) / tan δ(A) was calculated by averaging six tan δ(B) / tan δ(A) values, each measured three times in the longitudinal and transverse directions. Here, if the maximum extreme value of the tan δ-temperature curve in the range of more than -30°C but less than 30°C and the minimum value of tan δ in the range of more than -30°C but less than 30°C were divided by the minimum value, the loss tangent peak was deemed not to exist and tan δ(A) was deemed to be absent. Furthermore, if tan δ(A) was determined to be absent and tan δ(B) / tan δ(A) could not be calculated among the six measurements, the average value of tan δ(B) / tan δ(A) was calculated for the number of measurements for which calculation was possible.

[0092] (2-4) Maximum peak temperature of loss tangent From the loss tangent (tanδ)-temperature curve obtained in (2-1), the maximum peak temperature of the loss tangent observed in the range of more than -30°C and less than 120°C was determined. Here, for the maximum extreme value of the tanδ-temperature curve in the range of more than -30°C and less than 120°C and the minimum value of tanδ in the range of more than -30°C and less than 120°C, if the value obtained by dividing the maximum extreme value by the minimum value was less than 2.0, it was determined that no peak in the loss tangent was observed, and that there was no maximum peak temperature.

[0093] (3) Mechanical property evaluation (3-1) Breaking elongation L1 and L2, breaking strength S1 and S2 The machine direction (MD) of the film production process was defined as the longitudinal direction, and the transverse direction (TD) perpendicular to the machine direction in the film plane was defined as the transverse direction. The sample was cut into a 150 mm long x 10 mm wide rectangle. The sample was placed in a tensile tester (Orientec Co., Ltd. "Tensilon® Universal Testing Machine" RTG-1210) with an initial chuck distance of 30 mm so that the longitudinal direction was the tensile direction. Tensile tests were performed at a tensile speed of 300 mm / min under an atmosphere of 25±5°C and 65±10% RH. The strain (unit: %) until the sample broke was measured as the breaking elongation, and the maximum load at break was measured. The breaking strength (unit: MPa) was calculated by dividing the strain (unit: %) by the cross-sectional area of ​​the sample before the test (film thickness × width, as determined in (1)). Similar measurements were performed five times for each sample in the longitudinal and transverse directions, and the average breaking elongation in the longitudinal direction was defined as L1 (%), the average breaking strength as S1 (MPa), the average breaking elongation in the transverse direction as L2 (%), and the average breaking strength as S2 (MPa).

[0094] (3-2) Identifying samples with unknown orientation For films with an unknown orientation, cut them into a rectangular sample measuring 150 mm long x 10 mm wide with any direction facing up. <1> Then, the sample <1> The direction of the long side of the sample was defined as 0°. Next, a sample of the same size was placed so that the long side direction was rotated 15° to the right from the 0° direction. <2> Similarly, the rectangular sample was rotated 15° in the long side direction, and the sample was taken in the same way. <3> ~ <12> Next, the breaking strength of each rectangular sample was determined in the same manner as in (3-1), and the long side direction (main orientation axis direction) of the sample with the maximum breaking strength was defined as the longitudinal direction in the present invention, and the direction perpendicular to the main orientation axis was defined as the width direction.

[0095] (3-3) 120℃ heat shrinkage rate H1 (%) in the longitudinal direction, 120℃ heat shrinkage rate H2 (%) in the transverse direction The film was cut into a 150mm long x 10mm wide rectangle in both the longitudinal and transverse directions. A mark was made in the center 100mm of the film using an oil-based marker, and the length was measured using a universal projector to determine the initial length (I0). The measured film was then placed in a gear-type hot air oven adjusted to 120°C. A 2.1g load was attached to the bottom of the hanging film, and the film was heat-treated for 15 minutes while the gear was rotating. The film was then removed and cooled to room temperature. The length between the marks was then measured using a universal projector to determine the thermal shrinkage (IH). The 120°C thermal shrinkage (unit: %) was calculated from the measured I0 and IH using the following formula (2). Similar measurements were performed five times in each of the longitudinal and transverse directions of each film. The average value in the main orientation axis direction was defined as H1 (%), and the average value in the direction perpendicular to the main orientation axis direction was defined as H2 (%). 120℃ heat yield (%)=(I0-IH) / I0×100...Equation (2).

[0096] (4) Glass transition temperature and heat of crystal fusion ΔHm Measurements and analysis were carried out using a Rigaku Corporation differential scanning calorimeter "Thermo plus EVO2 DSCvesta" in accordance with JIS K7121-1987 and JIS K7122-1987. 5.0 mg of the sample was weighed and heated from -50°C to 200°C at a heating rate of 20°C / min. The glass transition temperature obtained during this heating period was calculated using the following formula.

[0097] Glass transition temperature = (extrapolated glass transition onset temperature + extrapolated glass transition end temperature) / 2 The extrapolated glass transition onset temperature is defined as the temperature at the intersection of a line drawn by extending the low-temperature baseline toward the high-temperature side and a tangent drawn at the point where the gradient of the step-change portion of the glass transition curve is maximum. The extrapolated glass transition finish temperature is defined as the temperature at the intersection of a line drawn by extending the high-temperature baseline toward the low-temperature side and a tangent drawn at the point where the gradient of the step-change portion of the glass transition curve is maximum.

[0098] In addition, the maximum peak temperature on the endothermic side of the DSC curve obtained under the above conditions was taken as the melting point of the resin or film, and the obtained melting point peak was analyzed to calculate the ΔHm (J / g) of the resin or film. When multiple endothermic peaks were present, the peak temperature with the largest endothermic amount was used as the melting point.

[0099] (5) Content of polyhydroxyalkanoic acid resin and resin components other than polyhydroxyalkanoic acid The aliphatic polyester film was dissolved in hexafluoroisopropanol (HFIP), 1 H-NMR and 13 The content (mass%) of polyhydroxyalkanoic acid resin was measured using C-NMR. The content (mass%) of resin components other than polyhydroxyalkanoic acid was calculated by subtracting the content (mass%) of polyhydroxyalkanoic acid resin from the total film, which was set at 100 (mass%). In the case of laminated films, each layer of the film was scraped off according to the laminate thickness to sample and evaluate the components constituting each layer alone. In the examples and comparative examples, the composition was calculated from the mixing ratio during film production.

[0100] (6) Crystallite size (6-1) Acquisition of 2D diffraction images The film sample was cut into pieces 2 cm long in the direction of the main orientation axis and 1 cm long in the direction perpendicular to the main orientation axis. A number of pieces with a total thickness of 100 μm or more were stacked directly on top of each other with their main orientation axes aligned in the same direction. The sample was then fixed in a holder so that X-rays were incident on the center of the sample in a direction perpendicular to the main orientation axis. Reflection measurements were then performed in the film thickness direction under the following conditions to obtain a two-dimensional X-ray diffraction image. Equipment: Bruker AXS D8 DISCOVER μHR Hybrid X-ray source: CuKα ray (using multilayer mirror), wavelength λ=0.15418nm Output: 50kV, 22mA Slit system: (X-ray source side) 1 mm 2 -1mm 2 -0.1mmΦ(sample side) Detector: 2D detector (Vantec500) Scan: 2θ=20° Elevation angle:ω=10° Camera length: 10cm Accumulation time: 300 seconds / frame.

[0101] (6-2) Orientation Profile From the diffraction image obtained in (6-1), the diffraction angle (2θ) was scanned in the range of 19° to 21° in 0.5° increments, from 40° to 140° at a circular angle with 90° in the thickness direction, and the scanned images were integrated to obtain an orientation profile.

[0102] (6-3) Orientation angle, degree of orientation A baseline was set at the minimum value of the orientation profile obtained in (6-2), and using a Gaussian distribution function, the peak with the highest intensity among the peaks with an orientation degree of 0.50 or more in the diffraction angle 2θ range of 19° to 21° was separated as PB. The peak position at this time was taken as the orientation angle (°). The orientation degree of PB was calculated from the half-width HO of the peak using the following formula. Orientation degree = (180-HO) / 180.

[0103] (6-4) 2θ profile in the orientation direction The range of ±10° of the orientation angle obtained from (6-3) was scanned in 0.05° increments, and the results were integrated to obtain a 2θ profile.

[0104] (6-5) Crystallite size A baseline was set at the minimum value of the 2θ profile obtained in (6-4), and the Gaussian distribution function was used to separate the peak with the highest intensity among the peaks with an orientation degree of 0.50 or greater in the diffraction angle (2θ) range of 19° to 21°. The crystallite size (nm) was calculated from the half-width of the separated peak using the Scherrer equation. The Scherrer constant was set to 0.9, and the half-width correction value was determined from the Si diffraction peak (111) measured using the above optical system using standard Si powder for X-ray diffraction manufactured by NIST.

[0105] (7) Biodegradability of the film 1 L of wet synthetic compost was prepared according to JIS K6954 (2008) and placed in a 10 L polypropylene container. Next, a 5 cm x 5 cm piece of evaluation film was cut out and placed in a polyethylene holder with a 2 cm square cutout on the inside, leaving the film inside the holder exposed to the outside.

[0106] The film sample, fixed in a holder, was then placed in a polypropylene container and placed in an oven controlled at 28±2°C for 60 days, following a method in accordance with JIS K6954 (2008). When placing the film sample, the entire 2cm square exposed film area in the holder was covered with the wet synthetic compost. After the initial placement, the film sample was removed every two days, the wet synthetic compost was stirred with a scoop, and the film sample was then placed again. This process was repeated.

[0107] Sixty days after initial addition, the film samples were removed from the container and photographed with a digital camera. The photographs were taken at a resolution of 1200 dpi (2 million pixels) or higher. The area of ​​the sample remaining within a 2 cm square frame inside the holder was determined from the photograph, and the collapsed area ratio (%) was calculated using the formula (initial area of ​​the sample within the holder - remaining area of ​​the sample within the holder) / (initial area of ​​the sample within the holder) x 100. A total of three holders were evaluated in the same compost, and the arithmetic mean of the three measurements was taken as the collapsed area ratio (%) of the film sample, and was judged according to the following criteria: Biodegradability of the film is preferably C or higher. A: Collapse area ratio is 30% or more B: Collapse area ratio is 15% or more but less than 30% C: Collapse area ratio is 5% or more but less than 15% D: Collapse area ratio is less than 5%.

[0108] (8) Breaking when the conveying speed and tension are changed (processability) A 300 mm wide, 200 m long film (wound on a 6-inch, 350 mm long core) was prepared and rewound onto a 3-inch, 350 mm long core under the conditions below. The conveying speed and tension were increased and the film was judged according to the following criteria. A: No tear occurred even when rewinding at a speed of 10 m / min and a conveying tension of 70 N / m. B: No tear occurred when rewinding at a speed of 8 m / min and a conveying tension of 70 N / m, but tear occurred when the speed was changed to 10 m / min and a conveying tension of 70 N / m. C: No tear occurred when rewinding at a speed of 5 m / min and a conveying tension of 70 N / m, but tear occurred when the speed was changed to 8 m / min and a conveying tension of 70 N / m. D: No tear occurred when rewinding at a speed of 5 m / min and a conveying tension of 50 N / m, but when the speed was changed to 5 m / min and a conveying tension of 70 N / m, tear occurred. E: When rewinding at a speed of 5 m / min and a conveying tension of 50 N / m, a tear occurred. The processability of the film is preferably D or higher.

[0109] (9) Water vapor barrier properties after aluminum deposition (barrier properties) <Aluminum vapor deposition method> The film was placed in a vacuum deposition device equipped with a film transport device, and the film was -2 After the pressure was reduced to a high vacuum of 100 Pa, the film was run on a cooled metal drum at 20°C while heating and evaporating aluminum metal, forming a vapor-deposited thin film layer on the film. The thickness of the vapor-deposited film was controlled to be 100 nm. After vapor deposition, the pressure inside the vacuum deposition device was returned to normal pressure, the wound film was rewound, and aged at 40°C for two days to obtain a laminate in which a vapor-deposited aluminum layer was laminated on the film.

[0110] <Method for evaluating water vapor barrier properties> The aluminum-deposited laminate was measured at a temperature of 40°C and a humidity of 90% RH using a water vapor transmission rate measuring device "PERMATRAN-W" (registered trademark) 3 / 30 manufactured by MOCON / Modern Controls. The measurement was carried out five times for each sample, and the average value was calculated to be the water vapor transmission rate of the film (unit: g / m 2 / day) The water vapor barrier properties of the laminate were evaluated based on the obtained water vapor permeability in accordance with the following criteria. A: 20g / m 2 / day or less B:20g / m 2 / day greater than 50g / m 2 / day or less C:50g / m 2 / day greater than 100g / m 2 / day or less D: 100g / m 2 Greater than / day The barrier property of the film is preferably C or higher.

[0111] (10) Heat sealability The laminate with the Y layer laminated as a heat seal layer was cut into a width of 10 cm and a length of 20 cm. Next, the cut-out laminates were stacked and tested using a heat seal tester manufactured by Tester Sangyo Co., Ltd., with a seal width of 10 mm, a heater temperature of 120°C, and a seal pressure of 2 kg / cm. 2 When heat-sealed widthwise with a sealing time of 1 second, the film's sealing quality was judged as follows based on the number of laminated sheets that showed visually noticeable deterioration in quality such as wrinkles or bubbles in the heat-sealed area. Heat sealing was performed starting with two sheets and at five locations 3cm apart in the longitudinal direction, and the number of sheets that showed deterioration in quality in at least one of the five locations was counted. Film sealing quality of C or higher is preferable. A: The quality does not deteriorate even with three sheets. B: The quality deteriorates after two sheets.

[0112] (11) Quietness of the film (noise level measurement) The sound insulation property of the film was measured and evaluated by the following method using an omnidirectional microphone set (1 / 2-inch electric microphone (UC-53A), preamplifier (NH-22)) manufactured by Lion Corporation, an FFT analyzer (SA-78), waveform analysis software (CAT-WAVE) manufactured by Catec Corporation, and a gel tester (specified in ASTM F-392).

[0113] An A4 sample was cut out so that the MD direction was the long side direction of the film, and both ends of the short side of the A4 cut sample were attached to the sample set part of the gel tester with double-sided tape, and a repeated fatigue test was performed for 30 seconds in a room temperature atmosphere. The sound emitted at that time was picked up by an omnidirectional microphone (UC-53A and NH-22) and SA-78 set at a position 5 cm away from the center of the film to obtain waveform data. The FFT conversion of the waveform data was performed by CAT-WAVE, and the noise level (dB) was collected. The same measurement was performed three times, and the average value of the obtained values was used as the noise level (dB) of the film and used as an index for evaluating the sound insulation property. In addition, the measurement was performed in a soundproof room to shut down external sounds, and in order to suppress the reverberation of sound in the gel tester, it was carried out with a sound-absorbing material (foamed PE) attached to the wall surface inside the gel tester. Also, the measurement conditions of SA-78 and the analysis conditions of CAT-WAVE were as follows. <FFT analyzer (SA-78)> · Calibration settings Calibration mode LIN Transfer value (Ach 1 EU = 4.31×10 -2 , Bch 1 EU = 1.11×10 -3 ) Reference value Ach 0dB EU = 2.0×10 -5 <Waveform analysis software (CAT-WAVE)> · Analysis mode: FFT&OCT · Trigger setting: Free · Analysis frequency: 20000Hz · Number of analysis points: 4096 · Time window function: Rectangular Averaging method: Frequency (Automatic) 12.5Hz intervals, 1600 points Measurement range: 14 cycles, 20.2 seconds (1 cycle is calculated at approximately 1.44 seconds) ·A characteristic The quietness was judged according to the following criteria: Quietness is preferably C or above. A: The noise level is less than 80dB, making it extremely quiet. B: Noise level is between 80dB and 85dB, making it quiet. C: The noise level is between 85dB and 90dB, making it less quiet but still practical for use. D: The noise level is over 90 dB, making it extremely quiet.

[0114] (12)MFR Measurements were performed in accordance with JIS K7210-1 (2014) at 210°C and 2.16 kg unless otherwise specified.

[0115] [Resin raw materials, etc.] The following resins were used to produce the aliphatic polyester films in each of the Examples and Comparative Examples. Note that polylactic acid may be referred to as "PLA" and polyhydroxyalkanoic acid as "PHA." Plasticizer-1, Plasticizer-2, and Plasticizer-3 are all plasticizers for polylactic acid-based resins. PHA: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) "BP350-05" manufactured by Blue Crystal Microorganisms. PLA-1: A crystalline polylactic acid resin with a melting point of 165°C, a glass transition temperature of 60°C, and an MFR (210°C / 2.16 kg) of 21 g / 10 min. PLA-2: Amorphous polylactic acid resin with a glass transition temperature of 60°C, MFR (210°C / 2.16 kg) of 10 g / 10 min, and no melting point observation. PLA-3: A crystalline polylactic acid resin with a melting point of 155°C, glass transition temperature of 60°C, and MFR (210°C / 2.16 kg) of 6 g / 10 min. PLA-4: Poly(meso-lactide), a linear copolymer obtained by polymerizing a mixture of approximately 90% meso-lactide and 10% L-lactide at 160-180°C in the presence of a tin catalyst. It is an amorphous polylactic acid resin with a glass transition temperature of 50°C, MFR (210°C / 2.16 kg) of 20 g / 10 min, and no observed melting point. PLA-5: Poly(lactide-co-glycolide), a copolymer of 60 mol% L-lactide and 40 mol% glycolide, is an amorphous polylactic acid resin with a glass transition temperature of 60°C, a MFR (210°C / 2.16 kg) of 15 g / 10 min, and no observed melting point. MA: Methyl acrylate polymer (weight average molecular weight 1000) manufactured by Soken Chemical & Engineering Co., Ltd., glass transition temperature -40°C, MFR (210°C / 2.16 kg) 23 g / 10 min. Plasticizer-1: "Tirabazole" (registered trademark) VR08: fatty acid ester manufactured by Taiyo Kagaku Co., Ltd., melting point 52°C. Plasticizer-2: Polyethylene glycol "PEG-4000N" (number average molecular weight 3100) manufactured by Sanyo Chemical Industries, Ltd., melting point 55°C. Plasticizer-3: Polyvinyl acetate "VINNEX-2523" manufactured by WACKER, melting point 166°C.

[0116] Example 1 A blend of 70% by mass of PHA as an aliphatic polyester resin raw material and 10% by mass of PLA-1 and 20% by mass of PLA-2 as resin raw materials other than PHA was fed into a single-screw extruder with a multi-stage temperature setting of 150 ° C in the raw material supply zone, 160 ° C in the compression zone, and 170 ° C in the metering zone. After melt-kneading, the extruded molten resin was removed from the filter zone set at 160 ° C using a 250 μm cut mesh filter. The mixture was then introduced into a T-die set at 160 ° C and extruded into a sheet. The extruded molten sheet was cooled and solidified on a casting drum maintained at 20 ° C to obtain an unstretched sheet.

[0117] Next, the unstretched sheet was introduced into an MD stretching process consisting of a continuous group of rolls. It was preheated to 30°C for 60 seconds using a group of rolls, then held at 70°C for 1 second and passed through a gap between rolls with a peripheral speed difference, where it was stretched 3.0 times in the longitudinal direction. The stretched film was then passed through a gap between rolls maintained at 30°C and cooled, and then cooled to room temperature to obtain a uniaxially oriented film. The resulting uniaxially oriented film was then introduced into a tenter, preheated to 70°C while holding both widthwise ends with clips, stretched 4.2 times in the widthwise direction at 75°C, and then heat-treated at 133°C while applying 12% relaxation in the widthwise direction. The film was then cooled to 50°C while still holding both widthwise ends with tension using clips, and introduced outside the tenter. The clips on both widthwise ends were then released. A 25 μm-thick film containing the aliphatic polyester was then wound into a roll using a winder. The properties of the resulting aliphatic polyester film are shown in Table 1.

[0118] (Examples 2 to 8, Examples 14 to 16, Comparative Examples 1 and 2) Aliphatic polyester films were obtained in the same manner as in Example 1, except that the raw material composition and film-forming conditions were changed as shown in the table. The properties of the obtained aliphatic polyester films are shown in the table. The film of Example 2 was excellent in both processability and barrier properties, and also excellent in both biodegradability and noise reduction. The film of Example 3 was excellent in both processability and barrier properties, and although slightly inferior in both biodegradability and noise reduction, it presented no problems in practical use. The film of Example 4 was excellent in both processability and barrier properties, and although slightly inferior in both biodegradability and noise reduction, it presented no problems in practical use. The film of Example 5 was excellent in all of biodegradability, processability, barrier properties, and noise reduction. The film of Example 6 was excellent in both processability and barrier properties, and although slightly inferior in both biodegradability and noise reduction, it presented no problems in practical use. The film of Example 7 was excellent in both biodegradability and noise reduction, and although slightly inferior in processability and barrier properties, it presented no problems in practical use. The film of Example 8 was excellent in barrier properties, and although slightly inferior in biodegradability, processability, and quietness, it presented no problems in practical use. The film of Example 14 was extremely excellent in biodegradability, processability, barrier properties, and quietness. The film of Example 15 was extremely excellent in processability, and excellent in biodegradability, barrier properties, and quietness. The film of Example 16 was excellent in processability, and although slightly inferior in biodegradability, barrier properties, and quietness, it presented no problems in practical use. The film of Comparative Example 1 was extremely excellent in processability and excellent in barrier properties, but very poor in biodegradability and quietness. The film of Comparative Example 2 was extremely excellent in quietness, and although slightly inferior in barrier properties, it presented no problems in practical use, and it was very poor in biodegradability and processability.

[0119] (Example 9, Comparative Examples 3 and 4) Aliphatic polyester films were obtained in the same manner as in Example 1, except that the raw material composition, extrusion temperature, and film-forming conditions were changed as shown in the table. The properties of the obtained aliphatic polyester films are shown in the table. The film of Example 9 was excellent in all of biodegradability, processability, barrier property, and noise reduction. The film of Comparative Example 3 was very excellent in both biodegradability and noise reduction, and had excellent processability, but very poor barrier property. The film of Comparative Example 4 was very excellent in processability and barrier property, but had very poor biodegradability and noise reduction.

[0120] Example 10 In Example 10, a laminate film was obtained by applying a heat sealing agent "Seikadyne" (registered trademark) BP-1910W manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. as a Y layer to the film (X layer) of Example 1 on the surface of the film that had been in contact with the casting drum during the film-forming process by gravure coating, adjusting the coating amount to a thickness of 2 μm. The properties of the resulting laminate film containing an X layer and a Y layer containing an aliphatic polyester are shown in the table.

[0121] (Examples 11 to 13) Aliphatic polyester films were obtained in the same manner as in Example 1, except that the resin components other than polyhydroxyalkanoic acid in the raw material composition and the film-forming conditions were changed as shown in the table. The properties of the obtained aliphatic polyester films are shown in the table. The film of Example 11 was very excellent in both processability and barrier properties, and was also excellent in both biodegradability and noise reduction. The film of Example 12 was excellent in all of biodegradability, processability, barrier properties, and noise reduction. The film of Example 13 was very excellent in processability, and was excellent in all of biodegradability and noise reduction, and although its barrier properties were slightly inferior, it presented no problems in practical use.

[0122] [Table 1]

[0123] [Table 2]

[0124] [Table 3]

[0125] [Table 4] [Industrial Applicability]

[0126] The present invention can provide a film containing an aliphatic polyester that is excellent in biodegradability, processability, quietness and barrier properties, and can be suitably used for packaging applications and agricultural, forestry and fisheries applications. [Explanation of symbols]

[0127] 1: Loss tangent tanδ(30) at 30℃ 2: Maximum peak of loss tangent tanδ(A) in the range of -30°C to 30°C 3: Maximum peak of loss tangent tanδ(B) in the range of 40℃ to 100℃ 4: Loss tangent tanδ(60) at 60℃

Claims

1. An aliphatic polyester film containing at least a polyhydroxyalkanoic acid, having a loss tangent (tanδ(30)) at 30°C in dynamic viscoelasticity measurement of 0.05 or more and 0.15 or less, and a maximum peak temperature of the loss tangent of 30°C or more and 100°C or less.

2. 2. The aliphatic polyester film according to claim 1, comprising at least two layers: an X layer comprising an aliphatic polyester film, and a Y layer different from the X layer.

3. 3. The aliphatic polyester film according to claim 1, wherein H1 (%) is a heat shrinkage rate at 120°C in the longitudinal direction and H2 (%) is a heat shrinkage rate at 120°C in the width direction, and both H1 and H2 are 0% or more and 20% or less.

4. 3. The aliphatic polyester film according to claim 1, wherein tan δ(A) is the maximum peak of the loss tangent in the temperature range of -30°C or higher and 30°C or lower, and tan δ(B) is the maximum peak of the loss tangent in the temperature range of 40°C or higher and 100°C or lower, and tan δ(A) and tan δ(B) satisfy formula (1). 0.8≦tanδ(B) / tanδ(A)≦10...Formula (1)

5. 3. The aliphatic polyester film according to claim 1, which has a loss tangent (tan δ(60)) at 60°C of 0.10 or more.

6. 3. The aliphatic polyester film according to claim 1, wherein the crystallite size calculated from the half-width of PB is 5 nm to 60 nm when the peak with the highest intensity among peaks with an orientation degree of 0.50 or more in the diffraction angle 2θ range of 19° to 21° is defined as PB in wide-angle X-ray diffraction in the thickness direction using CuKα radiation.

7. 3. The aliphatic polyester film according to claim 1, wherein S1 (MPa) is the breaking elongation in the longitudinal direction and S2 (MPa) is the breaking elongation in the width direction, and both S1 and S2 are 30 MPa or more and 280 MPa or less.

8. 3. The aliphatic polyester film according to claim 1, wherein L1 (%) is the breaking elongation in the longitudinal direction and L2 (%) is the breaking elongation in the width direction, and both L1 and L2 are 10% or more and 350% or less.

9. The aliphatic polyester film according to claim 1 , comprising 45% by mass or more of a polyhydroxyalkanoic acid relative to 100% by mass of the total mass of the film.

10. 10. The aliphatic polyester film according to claim 1, wherein the polyester film contains 1% by mass or more and 45% by mass or less of a crystalline polylactic acid-based resin and 1% by mass or more and 45% by mass or less of an amorphous polylactic acid-based resin and / or a plasticizer for polylactic acid-based resin, relative to 100% by mass of the total mass of the film.

11. The aliphatic polyester film according to claim 2 , wherein the X layer contains 45% by mass or more of polyhydroxyalkanoic acid relative to 100% by mass of the total mass of the X layer.

12. 12. The aliphatic polyester film according to claim 2 or 11, wherein the X layer contains, relative to a total mass (100 mass%) of the X layer, 1 mass% to 45 mass% of a crystalline polylactic acid-based resin and 1 mass% to 45 mass% of an amorphous polylactic acid-based resin and / or a plasticizer for polylactic acid-based resin.

13. The aliphatic polyester film according to claim 2 , wherein the Y layer comprises any one of an adhesive layer, a pressure-sensitive adhesive layer, a printing layer, and a heat-sealing layer.

14. 3. The aliphatic polyester film according to claim 1, further comprising a functional layer on at least one surface thereof.

15. A packaging material comprising the aliphatic polyester film according to claim 1 or 2.

16. A material for agriculture, forestry and fisheries, comprising the aliphatic polyester film according to claim 1 or 2.

17. 3. The aliphatic polyester film according to claim 1, which is used to cover agricultural, forestry, and fishery materials, wherein the agricultural, forestry, and fishery materials include at least one selected from the group consisting of fertilizers, feeds, seeds and seedlings, and chemicals.

18. 3. A material for agricultural, forestry and fisheries products, characterized by being covered with the aliphatic polyester film according to claim 1 or 2.

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