Aliphatic polyester film, package, material for agriculture, forestry, or fishery, and raw material for agriculture, forestry, or fishery

Abstract

The present invention addresses the problem of providing a film including an aliphatic polyester, the film being excellent in terms of processability, biodegradability, and freedom from noise generation and suitable for use in packaging applications and agricultural, forestry, and fishery applications. The film including an aliphatic polyester is an aliphatic polyester film which has at least one loss tangent peak in a range of -30°C to 30°C exclusive and in which, when a maximum loss tangent peak value in the range of -30°C to 30°C exclusive is expressed by tanδ(A) and a loss tangent at 30°C is expressed by tanδ(30A), the tanδ(A) and the tanδ(30A) satisfy expression (1). Expression (1): tanδ(A) / tanδ(30A)≥1.05

Description

Aliphatic polyester film, packaging, agricultural, forestry and fisheries materials, agricultural, forestry and fisheries ingredients

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

[0002] To curb global warming, countries around the world are undertaking various initiatives toward achieving carbon neutrality goals. Plastic products, in particular, are required to reduce their usage and waste, as they emit large amounts of CO2 during their production and disposal. Packaging plastics are particularly used in large quantities among various plastic products, and much of this material is disposable. Therefore, there is a need to reduce the usage and waste of packaging plastics, including film, and to recycle and replace them with plant-based materials. To reduce packaging plastic waste and CO2 emissions, the use of biodegradable plastics, such as compostable polylactic acid, is expected. However, particularly for applications requiring frequent handling and bending, such as snack packaging, quieter films are becoming increasingly important. However, compared to other thermoplastic packaging resin films, such as polyolefins, polylactic acid film is hard and brittle, resulting in a distinctive, harsh sound when subjected to external stresses such as crumpling and bending.

[0003] In response to this, films with excellent toughness have been proposed by blending polylactic acid resin with resins such as polybutylene succinate, polybutylene adipate terephthalate, 3-hydroxybutyrate-co-3-hydroxyhexanoate copolymer, and polyhydroxyalkanoic acid (Patent Document 1). Also, films with controlled impact resistance and heat shrinkage have been proposed by blending polylactic acid resin with a soft polypropylene-based resin (Patent Document 2). Furthermore, a film with controlled gas barrier properties and noise reduction has been proposed by using a laminated structure in which an amorphous polylactic acid resin is used for the surface layer and a resin in which a crystalline polylactic acid resin is blended with a soft block copolymer resin for the inner layer (Patent Document 3).

[0004] Japanese Patent Publication No. 2014-514372 Japanese Patent Publication No. 2008-75009 Japanese Patent Publication No. 2013-147580

[0005] However, Patent Document 1 improves mechanical strength and toughness by blending with other resins, but because the structure contains 70% by weight or more of polylactic acid, it cannot be said to be sufficient in terms of satisfying all of the requirements of biodegradability, quietness, and processability. Patent Document 2 also improves breaking elongation significantly and provides excellent processability by utilizing flexible polypropylene, but because it contains polypropylene, it does not achieve both biodegradability and quietness. Patent Document 3 also improves quietness by blending polylactic acid resin and flexible block copolymer resin in the inner layer of a three-layer laminate, but because the structure contains 65% by weight or more of polylactic acid, there is still room for improvement in biodegradability and quietness.

[0006] Therefore, an object of the present invention is to provide an aliphatic polyester film that is excellent in processability, biodegradability, and noise reduction, and that can be suitably used for packaging applications and agricultural, forestry, and fisheries applications.

[0007] The present inventors conducted extensive research to solve the above problems and have now invented the following film of the present invention. That is, one preferred aspect of the present invention is as follows: 1. An aliphatic polyester film containing a film having at least one loss tangent peak in the range of greater than -30°C and less than 30°C, and in which, when tan δ(A) is the maximum peak value of the loss tangent in the range of greater than -30°C and less than 30°C, and tan δ(30A) is the loss tangent at 30°C, tan δ(A) and tan δ(30A) satisfy formula (1): tan δ(A) / tan δ(30A)≧1.05... formula (1) 2. 1. The aliphatic polyester film according to Item 1, wherein when the heat shrinkage rate at 120°C in the longitudinal direction is Y1 (%) and the heat shrinkage rate at 120°C in the width direction is Y2 (%), both Y1 and Y2 are 15% or less, and when the thickness unevenness in the longitudinal direction is X1 (R%) and the thickness unevenness in the width direction is X2 (R%), both X1 and X2 are 0.1R% or more and 20R% or less. The thickness unevenness X1 and X2 (unit: R%) are calculated by dividing the average value of the measured film thickness by T. AV , the maximum value is T MAX , the minimum value is T MINThe thickness unevenness (R%) is calculated from the following formula (2): MAX -T MIN ) / T AV× 100 Formula (2) 3. The aliphatic polyester film according to 1. or 2., having tan δ(30A) of 0.05 or more and 0.15 or less, and having a maximum peak temperature of loss tangent of 30°C or more and 100°C or less. 4. The aliphatic polyester film according to any one of 1. to 3., comprising two layers: an X layer containing at least an aliphatic polyester, and a Y layer different from the X layer. 5. The aliphatic polyester film according to any one of 1. to 4., wherein, when the loss tangent at -30°C is tan δ(-30A), tan δ(A) and tan δ(-30A) satisfy Formula (3): tan δ(A) / tan δ(-30A)≧2.0 Formula (3) 6. The aliphatic polyester film according to any one of 1. to 5., wherein T(A)°C is the temperature at which the loss tangent is tan δ(A) and T(L)°C is the lower of the temperatures at which the loss tangent is tan δ(A) / 2, and T(A) and T(L) satisfy the following formula (4): T(A) - T(L) ≦ 35 (formula (4)) 7. The aliphatic polyester film according to any one of 1. to 6., further having at least one loss tangent peak in the range of 40°C to 100°C, and wherein tan δ(B) is the maximum peak value of the loss tangent in the range of 40°C to 100°C, and tan δ(A) and tan δ(B) satisfy the following formula (5): 0.8 ≦ tan δ(B) / tan δ(A) ≦ 10 (formula (5)) 8. The aliphatic polyester film according to any one of 1. to 7., 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 to 60 nm, where PB is the peak with the highest intensity among peaks with an orientation degree of 0.50 or more in a diffraction angle 2θ range of 19° to 21°. 9. The aliphatic polyester film according to any one of 1. to 8., wherein, when S1 (MPa) is the breaking strength in the longitudinal direction and S2 (MPa) is the breaking strength in the width direction, S1 and S2 satisfy the following formulas (6) and (7): 30≦S1≦280 ... formula (6) 30≦S2≦280 ... formula (7) 10. The aliphatic polyester film according to any one of 1. to 9., wherein the average pin puncture strength (20 μm equivalent value) is 80 gf or more and the coefficient of variation of the pin puncture strength (20 μm equivalent value) is 30% or less.11. The aliphatic polyester film according to any one of 1. to 10., wherein the aliphatic polyester film contains a polyhydroxyalkanoic acid, and the polyhydroxyalkanoic acid accounts for 45% by mass or more relative to 100% by mass of the total mass of the aliphatic polyester film. 12. The aliphatic polyester film according to any one of 1. to 11., wherein, when Fa is the average of the orientation parameters (I1720m / I1450m) in the longitudinal direction and the orientation parameter (I1720t / I1450t) in the width direction, and Fb is the average of the orientation parameters (I875m / I1770m) in the longitudinal direction and the orientation parameter (I875t / I1770t) in the width direction, as determined by cross-sectional observation in Raman spectroscopy evaluation, Fa and Fb satisfy formula (8): 0.6≦(Fb-Fa)≦2.5 (8) 13. The aliphatic polyester film according to any one of 1. to 12., further comprising a functional layer on at least one surface. 14. A packaging body comprising the aliphatic polyester film described in any one of 1. to 13.. 15. An agricultural, forestry and fishery material comprising the aliphatic polyester film described in any one of 1. to 13.. 16. A film used to cover agricultural, forestry and fishery materials, the agricultural, forestry and fishery materials comprising one or more selected from fertilizers, feeds, seeds and seedlings, and chemicals, the aliphatic polyester film described in any one of 1. to 13.. 17. An agricultural, forestry and fishery material covered with the aliphatic polyester film described in any one of 1. to 13.

[0008] The aliphatic polyester film obtained by the present invention has excellent processability, biodegradability, and noise reduction properties, and can be suitably used for packaging applications and agricultural, forestry, and fisheries applications.

[0009] FIG. 1 illustrates a graph of the tan δ vs. temperature curve for a film of the present invention.

[0010] The film of the present invention will be described in detail below. When the upper and lower limits of a preferred range are separately stated below, any combination of these limits may be used. The "aliphatic polyester film of the present invention" may be collectively referred to as "the present invention" or "the film of the present invention." In the present specification, the "film containing an aliphatic polyester" may be simply referred to as "film." 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. If the stretching directions (longitudinal and width directions) are unknown, the breaking strength at break can be measured in the mechanical property evaluation described below. 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.

[0011] It is important that the film of the present invention has at least one peak of loss tangent in the range of more than -30°C and less than 30°C, and when the maximum peak value of the loss tangent in the range of more than -30°C and less than 30°C is tanδ(A) and the loss tangent at 30°C is tanδ(30A), the values ​​of tanδ(A) and tanδ(30A) satisfy the formula (1): tanδ(A) / tanδ(30A)≧1.05... formula (1)

[0012] The maximum peak value of the loss tangent, tanδ(A), is presumed to be derived from the amorphous structure of the aliphatic polyester component of the film of the present invention, and the shape of the peak indicates the uniformity of the amorphous structure, while the peak temperature, T(A)°C, corresponds to the constrained state of the amorphous structure in an oriented state, i.e., the glass transition temperature. Therefore, a tanδ(A) / tanδ(30A) of 1.05 or more means that the film has a glass transition temperature in the range of greater than -30°C and less than 30°C, indicating high mobility of amorphous molecular chains in the film in a low-temperature environment, facilitating biodegradation in a low-temperature to room-temperature range, such as home composting. Furthermore, the film's excellent flexibility in a low-temperature to room-temperature range also suppresses harsh sounds generated by folding or crumpling when used as a packaging bag, resulting in excellent quietness.

[0013] From the above viewpoints, tan δ(A) / tan δ(30A) is preferably 1.10 or more, more preferably 1.13 or more, even more preferably 1.15 or more, and particularly preferably 1.20 or more. Although there is no particular upper limit for tan δ(A) / tan δ(30A), a value of 4.0 or less is preferred, since excessive amorphous molecular motion may result in insufficient breaking strength to withstand transport during bag-making, for example, and thus deteriorated processability.

[0014] The method for controlling tan δ(A) / tan δ(30A) within the above range is not particularly limited, but examples include blending resins with different glass transition temperatures and melt viscosities, as described below, using a resin with a low water content during film formation, and further performing slight stretching after biaxial stretching. The film may be a multilayer laminate, and in the case of a laminate film, formula (1) is measured for the entire laminate film. In the case of a single-layer film, formula (1) is measured for the single-layer film. It is also preferable that formula (1) is satisfied when a film layer containing an aliphatic polyester is sampled from a laminate such as a laminate of multiple sheets and the sampled layer is measured.

[0015] In the film of the present invention, when the heat shrinkage rate at 120°C in the longitudinal direction is Y1 (%) and the heat shrinkage rate in the width direction is Y2 (%), it is preferable that both Y1 and Y2 are 15% or less. By setting Y1 and Y2 to 15% or less, the dimensional stability of the film is sufficiently high in both the longitudinal and width directions, and the occurrence of wrinkles and slack that cause tears and defects during processing at high temperatures and high speeds can be suppressed.

[0016] From the above viewpoints, Y1 and Y2 are each more preferably 12% or less, even more preferably 7% or less, and particularly preferably 5% or less. The lower limits of Y1 and Y2 are not particularly limited, but are preferably 0.1% or more, more preferably 0.3% or more, from the viewpoint of preventing wrinkles and slack due to thermal expansion during high-temperature, high-speed processing. The preferred ranges for Y1 and Y2 are 0.1% or more and 12% or less, more preferably 0.3% or more and 7% or less, and even more preferably 0.3% or more and 5% or less, from the viewpoint of preventing wrinkles and slack that can cause tears and defects during high-temperature, high-speed processing. In this specification, the 120°C heat shrinkage can be determined as the percentage change in film length before and after heat-treating a film in a predetermined direction at 120°C for 15 minutes.

[0017] The method for controlling Y1 and Y2 within the above ranges is not particularly limited, but examples thereof include a method of adjusting the stretching ratio during film formation, and a method of adjusting the conditions of heat treatment and relaxation treatment after stretching, as will be described later.

[0018] In the film of the present invention, when the thickness unevenness in the longitudinal direction is X1 (R%) and the thickness unevenness in the width direction is X2 (R%), it is preferable that both X1 and X2 are 0.1R% or more and 20R% or less. By setting X1 and X2 to 20R% or less, the quality of the thickness unevenness is sufficiently high in both the longitudinal and width directions, and the occurrence of cracks during vapor deposition processing and the occurrence of wrinkles during heat sealing processing can be further suppressed, thereby further improving the barrier properties and seal quality of the package. Note that the thickness unevenness X1 and X2 (unit: R%) are calculated by randomly selecting five positions in the film and measuring the average value of the film thickness at 1cm intervals for 30 cm in the longitudinal direction and 1cm intervals for 30 cm in the width direction from each of the five positions. AV , the maximum value is TMAX , the minimum value is T MIN The thickness unevenness (R%) is calculated from the following formula (2) and the average of the five points is taken as the thickness unevenness (R%). MAX -T MIN ) / T AV ×100 Formula (2) More specifically, it is determined by the method described in the examples.

[0019] From the above viewpoints, X1 and X2 are each more preferably 15R% or less, even more preferably 12R% or less, even more preferably 10%R or less, and particularly preferably 5R% or less. The lower limits of X1 and X2 are 0.1R%, and from the viewpoint of preventing wrinkles during high-speed processing due to excessive surface smoothing, they are preferably 0.2R% or more, and more preferably 0.3R% or more. The more preferred ranges for X1 and X2 are 0.2R% or more and 15R% or less, even more preferably 0.3R% or more and 12R% or less, even more preferably 0.3R% or more and 10R% or less, and particularly preferably 0.3R% or more and 5R% or less, which are preferred from the viewpoints of further suppressing cracks during vapor deposition processing and wrinkles during heat sealing processing, and further improving the barrier properties and seal quality of the package.

[0020] The method for controlling X1 and X2 within the above ranges is not particularly limited, but examples thereof include a method of adjusting the stretching ratio, a method of further performing slight stretching after biaxial stretching, and a method of adjusting the conditions of heat treatment and relaxation treatment after stretching, as will be described later.

[0021] The film of the present invention preferably has a tan δ (30A) of 0.05 or more and 0.15 or less. By having a tan δ (30A) within the above range, the film can be made to be easily biodegradable in home compost. This is thought to be because a tan δ (30A) of 0.05 or more facilitates the movement of amorphous molecular chains in the film at room temperature. The tan δ (30A) can be controlled by controlling the amorphous structure of the aliphatic polyester, preferably the polyhydroxyalkanoic acid resin, in the film of the present invention. From the viewpoints of biodegradability and quietness, the tan δ (30A) is more preferably 0.06 or more, and even more preferably 0.07 or more. On the other hand, if the tan δ (30A) 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 excessive wrinkling. Therefore, the tan δ (30A) is more preferably 0.14 or less, and even more preferably 0.13 or less. Furthermore, a more preferred range of tan δ(30A) is 0.06 or more and 0.14 or less, and even more preferably 0.07 or more and 0.13 or less, from the viewpoints of facilitating biodegradability in home composting and suppressing wrinkles during film transport. The method for controlling tan δ(30A) is not particularly limited, but examples include blending resins with different glass transition temperatures and melt viscosities, as described below, and blending a polyhydroxyalkanoic acid resin with a crystalline polylactic acid resin and an amorphous polylactic acid resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid under the above conditions to control the amount of amorphous components that are mobile at 30°C.

[0022] The film of the present invention preferably has a maximum peak temperature of the loss tangent of 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, when the value obtained by dividing the maximum extreme value by the minimum value is 2.0 or higher, is considered to be the maximum peak temperature. When the value obtained by dividing the maximum extreme value by the minimum value is less than 2.0, the film is considered to have no maximum peak. When the film is processed into packaging bags and there is a fluctuation in conveying tension in an environment where the film is exposed to heat of 30°C or higher, if the maximum peak temperature of the loss tangent is within the preferred range, the film can follow the fluctuation with appropriate flexibility and also have appropriate rigidity, which suppresses breakage and ensures excellent processability. Furthermore, suppressing wrinkling during vapor deposition improves the quality of the vapor-deposited film, thereby improving the barrier properties after vapor deposition. This is believed to be due to the presence of an amorphous structure in the film that is resistant to glass transition at low temperatures.

[0023] From the above viewpoints, 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, so the maximum peak temperature is preferably 90°C or lower, more preferably 80°C or lower, and particularly preferably 70°C or lower. Furthermore, a more preferred range for the maximum peak temperature of the loss tangent is 35°C or higher and 90°C or lower, more preferably 40°C or higher and 80°C or lower, and even more preferably 45°C or higher and 70°C or lower, from the viewpoint of improving processability and barrier properties after vapor deposition. The method for controlling the maximum peak temperature of the loss tangent within the above range is not particularly limited, but examples include a method of blending a polyhydroxyalkanoic acid resin with a crystalline polylactic acid-based resin and an amorphous polylactic acid-based resin as an aliphatic polyester resin other than polyhydroxyalkanoic acid, as described below, and a method of biaxially stretching the film to an area 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.

[0024] From the viewpoint of excellent processability, biodegradability, and quietness, and of being suitable for use in packaging applications and agricultural, forestry, and fisheries applications, the film of the present invention is preferably a laminated aliphatic polyester film including at least two layers: an X layer containing an aliphatic polyester, and a Y layer different from the X layer. Here, from the viewpoint of production costs and use as a quiet packaging material, it is preferable that the Y layer includes any one of an adhesive layer, a pressure-sensitive adhesive layer, a printing layer, and a heat-sealing layer.

[0025] The film of the present invention has at least one peak of loss tangent in the range of more than -30°C and less than 30°C, and when the maximum peak value of the loss tangent in the range of more than -30°C and less than 30°C is tanδ(A) and the loss tangent at -30°C is tanδ(-30A), it is preferable that tanδ(A) and tanδ(-30A) satisfy formula (3): tanδ(A) / tanδ(-30A)≧2.0... formula (3)

[0026] A tan δ (A) / tan δ (-30A) of 2.0 or more means that the tan δ at -30°C is low and the film structure is stable. This in turn means that the film has high breaking strength and excellent processability when used as a packaging material.

[0027] From the above viewpoints, tan δ(A) / tan δ(-30A) is preferably 3.0 or more, more preferably 5.0 or more, even more preferably 8.0 or more, and particularly preferably 11.0 or more. Although there are no particular limitations on the upper limit of tan δ(A) / tan δ(-30A), a value of 20 or less is preferred, since excessive amorphous molecular motion can result in insufficient strength to withstand transportation during bag-making, for example, and deteriorated processability.

[0028] The method for controlling tan δ(A) / tan δ(−30A) within the above range is not particularly limited, and examples thereof include a method of blending resins having different glass transition temperatures and melt viscosities as will be described later, a method of using a resin with a low water content during film formation, and a method of further slightly stretching the film after biaxial stretching.

[0029] The film of the present invention preferably has at least one peak of loss tangent in the range of more than -30°C and less than 30°C, and when the maximum peak value of the loss tangent in the range of more than -30°C and less than 30°C is tan δ(A), the temperature at which the loss tangent shows tan δ(A) is T(A)°C, and the lower temperature among the temperatures at which the loss tangent becomes tan δ(A) / 2 is T(L)°C, it is preferable that T(A) and T(L) satisfy the formula (4): T(A) - T(L) ≦ 35 ... formula (4)

[0030] A film that satisfies the above formula (4) contains an aliphatic polyester with a glass transition temperature at room temperature or below, which is highly biodegradable, and indicates that the amorphous structure of the polyester is formed sufficiently uniformly in the stretch-oriented film, facilitating efficient biodegradation. Furthermore, satisfying the above formula (4) means that the film has a sharp tan δ curve above -30°C and below 30°C, which means that the film has a high sound-absorbing effect, efficiently absorbing the vibration energy of sound generated in this temperature range and dissipating it as heat energy. This suppresses the harsh sounds generated by folding or crumpling when used as a packaging bag, resulting in excellent quietness.

[0031] From the above viewpoints, T(A) - T(L) is more preferably equal to or lower than 27° C., even more preferably equal to or lower than 25° C., even more preferably equal to or lower than 20° C., and particularly preferably equal to or lower than 15° C. As described above, the method for controlling T(A) and T(L) so that they satisfy formula (4) is not particularly limited, but examples thereof include a blend of resins having different glass transition temperatures and melt viscosities, as will be described later, a method using a resin with a low water content during film formation, and a method in which slight stretching is further performed after biaxial stretching.

[0032] The film of the present invention has at least one loss tangent peak 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 value of the loss tangent in the range of more than -30°C but less than 30°C is tan δ(A) and the maximum peak value of the 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 the following formula (5): 0.8≦tan δ(B) / tan δ(A)≦10... formula (5)

[0033] The peak of the loss tangent in the range of 40°C or higher and 100°C or lower is presumed to be derived from a resin component having a high glass transition temperature that is preferable when used in combination with the aliphatic polyester, and the ratio of the maximum value of tan δ(B) to tan δ(A) derived from the aliphatic polyester is an index representing the uniformity of the amorphous structure and the mixed state thereof in the stretch-oriented film.

[0034] A film satisfying the above formula (5) shows that the aliphatic polyester having a glass transition temperature below room temperature, which is excellent in biodegradability, and the aliphatic polyester having a high glass transition temperature, which is excellent in heat resistance, are phase-separated and uniformly present within a moderate range, and a film having such a structure is likely to efficiently proceed with biodegradation. From the above viewpoint, tan δ(B) / tan δ(A) is more preferably 1.0 or more and 5.0 or less, and even more preferably 1.5 or more and 3.0 or less. The method for controlling tan δ(B) / tan δ(A) within the preferred range is not particularly limited, but examples include blending resins with different glass transition temperatures and melt viscosities, as described below, using a resin with a low water content during film formation, and further performing slight stretching after biaxial stretching.

[0035] In the film of the present invention, when the highest intensity peak among peaks with an orientation degree of 0.50 or more in the diffraction angle 2θ range of 19° to 21° in the thickness direction is measured by wide-angle X-ray diffraction using CuKα radiation, the crystallite size calculated from the half-width of PB is preferably 5 nm to 60 nm. The diffraction peak is derived from the crystalline structure of polyhydroxyalkanoic acid, which contributes to the breaking strength, flexibility, and biodegradability of the film. When the orientation degree is 0.50 or more, while a crystalline structure with excellent biodegradability exists in the film, its orientation is high in the plane direction, making it less likely to become the starting point of breakage upon impact, and also improving the flexibility of the film. By setting the crystallite size of crystals with such an orientation degree to 5 nm or more, a crystalline structure with excellent biodegradability and sufficiently high orientation can be formed in the film, further improving the biodegradability of the film. In addition, when the film is used for, for example, packaging applications or agricultural, forestry, and fisheries applications, sagging during processing and transportation that may occur can be suppressed, and the film can be prevented 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 the strength of the film. In addition, when the present film is used for, for example, packaging applications or agricultural, forestry, and fisheries applications, it is possible to prevent the film from being extremely deformed, and to reduce the deterioration of properties caused by cracking or cleavage when a functional layer such as a vapor deposition layer is provided. It is also possible to improve biodegradability. From the above viewpoint, 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 viewpoint, the crystallite size is more preferably 50 nm or less, even more preferably 40 nm or less, even more preferably 30 nm or less, particularly preferably 25 nm or less, and most preferably 20 nm or less. Furthermore, a more preferred range of the crystallite size is 7 nm or more and 40 nm or less, even more preferably 9 nm or more and 30 nm or less, even more preferably 11 nm or more and 25 nm or less, and particularly preferably 11 nm or more and 20 nm or less, which is preferable from the viewpoint of further improving the biodegradability of the film and improving processability and barrier properties after vapor deposition.The measurement by wide-angle X-ray diffraction in the thickness direction using CuKα rays is carried out by the method described in the examples.

[0036] 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 stretching ratio in the stretching step during film formation and the heat treatment temperature in the heat treatment and relaxation treatment steps, and a method of performing slight stretching after the heat treatment and relaxation treatment steps. More specifically, by setting the longitudinal stretching ratio to 1.5 to 4.2 times, the transverse stretching ratio to 1.5 to 4.2 times, or the areal stretching ratio to 4 to 18 times, the crystallite size generated in the preheating section can be controlled to a preferred range by physical stretching stress. Furthermore, by performing heat treatment at (melting point (°C) of the polyhydroxyalkanoic acid resin - 100°C) to (melting point (°C) of the polyhydroxyalkanoic acid resin - 10°C) after biaxial stretching, crystal growth can be controlled. Furthermore, by applying tension to the conveying speed of the subsequent winding process at 100.1% or more and 110.0% or less relative to the tenter outlet conveying speed after heat treatment and relaxation treatment, the crystallite size generated by the stretching and heat treatment can be controlled to a more preferable range by physical stretching stress. If the stretching ratio is lower than the above range, the crystal size may remain coarse after film formation, and if it is higher than the above range, the crystal size may become excessively small. Furthermore, if the heat treatment temperature is lower than the upper range, crystal growth may be insufficient, and if it is higher than the above range, only the grown coarse crystals may remain. Furthermore, if the micro-stretching is lower than the above range, the crystal size may not be controlled to be too small, and if it is higher than the above range, the crystal size may become excessively small or the film may break.

[0037] 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 0.98 or less, particularly preferably 0.97 or less. Furthermore, from the viewpoint of obtaining an improvement in strength due to moderate orientation of the crystals, the degree of orientation is not particularly limited, but is preferably 0.50 or more, more preferably 0.75 or more, even more preferably 0.90 or more, and particularly preferably 0.95 or more. Note that, from the viewpoint of appropriately measuring a film with high 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 circumferential angle of 90°±10°. The method for controlling the degree of orientation within the above range is not particularly limited, but examples include a method of adjusting the stretch ratio in the stretching step during film formation or the heat treatment temperature in the heat treatment and relaxation treatment steps, and a method of performing slight stretching after the heat treatment and relaxation treatment steps.

[0038] 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 S1 and S2 satisfy the following formulas (6) and (7): 30≦S1≦280 (6) 30≦S2≦280 (7)

[0039] By setting S1 and S2 to 30 MPa or more, it is possible to suppress a decrease in processability caused by excessively high flexibility of the film. Furthermore, by setting S1 and S2 to 280 MPa or less, it is possible to suppress a decrease in processability caused by excessively high rigidity of the film. From the above perspective, S1 and S2 are more preferably 35 MPa or more and 240 MPa or less, and even more preferably 40 MPa or more and 200 MPa or less. The method for controlling S1 and S2 within the above range is not particularly limited, but examples thereof include a method of using a resin with a low water content during film formation and a method of further slightly stretching the film after biaxial stretching, as described below.

[0040] In the film of the present invention, when the breaking elongation in the longitudinal direction is L1 (%) and the breaking elongation in the width direction is L2 (%), it is preferable that both L1 and L2 are 10% or more and 350% or less. By setting L1 and L2 to 10% or more, it is possible to suppress a decrease in processability caused by excessively low toughness and flexibility of the film. Furthermore, by setting L1 and L2 to 350% or less, it is possible to suppress a decrease in processability caused by excessively high flexibility of the film. From the above viewpoint, L1 and L2 are more preferably 50% or more and 330% or less, and even more preferably 90% or more and 310% or less. The method for controlling L1 and L2 within the above ranges is not particularly limited, but an example thereof is a method using a resin with a low water content during film formation, as described below.

[0041] The film of the present invention preferably has an average puncture strength (20 μm equivalent) of 80 gf or more. By making the puncture strength (20 μm equivalent) of the film 80 gf or more, the film is sufficiently oriented by stretching, thereby increasing strength and pinhole resistance and suppressing deterioration of processability and barrier properties at high temperatures and high speeds. From the above perspectives, the puncture strength (20 μm equivalent) is more preferably 150 gf or more, and even more preferably 200 gf or more. Furthermore, there is no particular limitation on the upper limit of the puncture strength (20 μm equivalent), but from the perspective of preventing deterioration of sealing quality due to excessive strength increase, it is preferably 1500 gf or less, more preferably 1000 gf or less, and even more preferably 800 gf or less. Furthermore, from the viewpoint of achieving both strength and processability, the puncture strength (20 μm equivalent) is more preferably in the range of 80 gf to 1500 gf, more preferably 150 gf to 1000 gf, and even more preferably 200 gf to 800 gf. The puncture strength (20 μm equivalent) is determined by the method described in the examples.

[0042] Furthermore, the coefficient of variation of the puncture strength (20 μm equivalent value) as evaluated by the method described below is preferably 30% or less. By setting the coefficient of variation of the puncture strength to 30% or less, it is possible to suppress a decrease in barrier properties due to the occurrence of localized pinholes and a decrease in sealing quality due to the occurrence of bubbles during heat sealing. From the above viewpoints, the coefficient of variation of the puncture strength is more preferably 20% or less, and even more preferably 15% or less.

[0043] The method for controlling the pin puncture strength (20 μm equivalent value) and its coefficient of variation within the above range is not particularly limited, but examples thereof include a method using a polyhydroxyalkanoic acid containing a specific resin component, a method adjusting the stretching ratio, and a method adjusting the conditions for heat treatment and relaxation treatment after stretching, as will be described later.

[0044] In the film of the present invention, when the average value of the orientation parameter (I1720m / I1450m) in the longitudinal direction and the orientation parameter (I1720t / I1450t) in the width direction determined by cross-sectional observation in Raman spectroscopy evaluation is defined as Fa, and the average value of the orientation parameter (I875m / I1770m) in the longitudinal direction and the 30A (I875t / I1770t) in the width direction is defined as Fb, it is preferable that Fa and Fb satisfy the following formula (8): 0.6≦(Fb−Fa)≦2.5... formula (8)

[0045] The larger the values ​​of Fa and Fb, the higher the state of orientation. Furthermore, as described below, the Fb value tends to be relatively large. Therefore, by setting (Fb - Fa) to 0.6 or more, good processability can be obtained due to the orientation of aliphatic polyester polylactic acid resins and resins with similar structures. Furthermore, by setting (Fb - Fa) to 2.5 or less, aliphatic polyester polyhydroxyalkanoic acid resins and resins with similar structures can be sufficiently oriented, resulting in good processability. From the above perspective, (Fb - Fa) is more preferably 0.7 or more and 2.1 or less, even more preferably 0.9 or more and 1.9 or less, and particularly preferably 1.2 or more and 1.6 or less.

[0046] The orientation parameter Fa determined by cross-sectional observation of the Raman spectroscopic evaluation is a parameter that indicates the orientation state of the molecular chain of a polyhydroxyalkanoic acid resin of an aliphatic polyester or a resin having a similar structure, and has a 1720 cm band derived from the C═O stretching band of the ester group, which is highly sensitive to the orientation state of the molecular chain. -1 The Raman band intensity around 1450 cm originates from the CH bending vibration, which is perpendicular to the molecular chain and has low sensitivity to the orientation state. -1 On the other hand, Fb is a parameter that indicates the orientation state of the molecular chains of aliphatic polyester polylactic acid resins and resins with similar structures, and is derived from the C-C stretching band at 875 cm, which is highly sensitive to the orientation state of the molecular chains. -1 The Raman band intensity around 1770 cm originates from the C═O stretching band perpendicular to the molecular chain. -1 In other words, appropriate processability can be obtained by controlling the degree of orientation of the molecular chains of the polylactic acid resin or resins having a similar structure in the film to be higher than the degree of orientation of the molecular chains of the polyhydroxyalkanoic acid resin or resins having a similar structure, while preventing the degree of orientation of the molecular chains of the polyhydroxyalkanoic acid resin or resins having a similar structure from becoming excessively small.

[0047] Here, polylactic acid resin is composed of optical isomers of L-lactic acid (L-form) and D-lactic acid (D-form), and the ratio and arrangement of these isomers affect the crystallinity and orientation. From this perspective, in order to increase the degree of orientation of the molecular chains of polylactic acid resin, it is preferable to contain a polylactic acid resin with a small amount of D-form, and the amount of D-form is preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less, relative to the total amount of L-form and D-form (100%).

[0048] On the other hand, polyhydroxyalkanoic acid resins generally crystallize relatively quickly, and therefore crystallization may proceed before the molecular chains are sufficiently oriented during stretching, or the molecular chains have low flexibility due to their molecular skeleton, making orientation by stretching difficult.From the viewpoints of orientation control by stretching and ease of production using biomass raw materials such as vegetable oils, 3-hydroxyalkanoates (P3HA) produced by microorganisms are preferred. Among P3HAs, from the viewpoint of ease of industrial production, poly(3-hydroxybutyrate) (P3HB), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P3HB3HV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (P3HB3HV3HH), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) are preferably used.

[0049] In a more preferred embodiment, the film of the present invention contains a polyhydroxyalkanoic acid resin and a polylactic acid resin as an aliphatic polyester other than the polyhydroxyalkanoic acid resin, thereby orienting the molecular chains of the polyhydroxyalkanoic acid resin, which is generally difficult to orient, and, in combination with the molecular chain orientation of the easily orientable polylactic acid resin, the film as a whole exhibits a moderate degree of orientation, and excellent processability can be obtained by controlling (Fb-Fa). The method for controlling (Fb-Fa) within the preferred range of the present invention is not particularly limited, but includes, as will be described later, a method of adjusting the stretching ratio in the stretching step during film formation and the heat treatment temperature in the heat treatment and relaxation treatment steps, and a method of performing slight stretching after the heat treatment and relaxation treatment steps to restore and enhance the molecular chain orientation of the polylactic acid resin or polyhydroxyalkanoic acid resin that has been relaxed more than necessary in the heat treatment and relaxation treatment steps.

[0050] From the viewpoint of controlling (Fb-Fa) and improving processability, the content of polyhydroxyalkanoic acid is preferably 45% by mass or more, more preferably 55% by mass or more, and even more preferably 65% ​​by mass or more, relative to the total mass of the film (100% by mass). The upper limit is not particularly limited, but is set to 99% by mass. Furthermore, it is preferable that the aliphatic polyester other than polyhydroxyalkanoic acid contains a biodegradable aliphatic polyester, and its content is preferably 1% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to the total mass of the film (100% by mass). Specific examples of 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 with a higher glass transition temperature or melting point than the polyhydroxyalkanoic acid, which is the main component. Among these, polylactic acid, which has both a high glass transition temperature and a high melting point, is particularly preferred.

[0051] The film may contain various additives, such as organic particles, inorganic particles, antioxidants, heat stabilizers, slipping agents, antistatic agents, antiblocking agents, fillers, viscosity modifiers, and coloring inhibitors, as long as the additives do not impair the object of the present invention. However, the resin content in the film is preferably 95% by mass or more.

[0052] The aliphatic polyester constituting the film of the present invention preferably includes polyhydroxyalkanoic acid, polylactic acid, polyglycolic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, polycaprolactone, etc., and among these, polyhydroxyalkanoic acid is preferred. Here, polyhydroxyalkanoic acid is a polymer containing hydroxyalkanoic acid as a constituent component, for example, a 3-hydroxyalkanoate repeating unit represented by the general formula [—CHR—CH—CO—O—] (wherein R is C n H 2n+1where 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:

[0053] 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.

[0054] 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.

[0055] The melting point and crystallinity of polyhydroxyalkanoic acids, including P3HA, can be adjusted by changing the composition ratio of the repeating units. Although polyhydroxyalkanoic acids are generally known to be susceptible to thermal decomposition, by designing a copolymer structure of two or more hydroxyalkanoic acids to have a low melting point, it is possible to lower the extrusion temperature.

[0056] The film of the present invention preferably contains polyhydroxyalkanoic acid as an aliphatic polyester, and from the viewpoint of improving composting at room temperature and biodegradability in the ocean, it is preferable that the polyhydroxyalkanoic acid content be 45% by mass or more relative to the total mass of the film (100% by mass).

[0057] 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 content of polyhydroxyalkanoic acid is preferably 45% by mass or more relative to the total mass of the X layer containing polyhydroxyalkanoic acid (100% by mass).

[0058] Here, the film of the present invention can maintain biodegradability while controlling noise reduction and breaking strength by containing a polyhydroxyalkanoic acid component and a biodegradable resin component with excellent heat resistance in appropriate ranges, both of which are aliphatic polyesters having a glass transition temperature below room temperature. The content of the biodegradable resin component with excellent heat resistance is preferably 55% by mass or less, when the total mass of the film of the present invention is taken as 100% by mass. Furthermore, the film of the present invention preferably contains 55% by mass or less of the X layer, when the total mass of the X layer containing the aliphatic polyester is taken as 100% by mass. If the content of the biodegradable resin component with excellent heat resistance exceeds 55% by mass, the polyhydroxyalkanoic acid component may be insufficient, resulting in reduced noise reduction and biodegradability, or stretching may become non-uniform, resulting in variations in biodegradation rate and disintegration. The lower limit of the content of the biodegradable resin component with excellent heat resistance is not particularly limited, but is preferably 1% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, from the viewpoint of preventing a decrease in breaking strength suitable for processing. Specifically, as a biodegradable resin component with excellent heat resistance, it is preferable to select a biodegradable aliphatic polyester other than polyhydroxyalkanoic acid from the viewpoint of increasing the affinity between resins and achieving quietness. 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 that has a higher glass transition temperature or melting point than the main component, polyhydroxyalkanoic acid, and even more preferable to select a resin that has both a high glass transition temperature and a high melting point.

[0059] The film of the present invention may contain various additives, such as organic particles, inorganic particles, antioxidants, heat stabilizers, slipping agents, antistatic agents, antiblocking agents, fillers, viscosity modifiers, and coloring inhibitors, as long as the object of the present invention is not impaired.

[0060] The film of the present invention can be used for a wide variety of purposes, including packaging applications, release applications, and process films for the production of packaging materials, packaging materials, sanitary products, agricultural, forestry, and fishery products (agricultural, forestry, and fishery materials), construction products, medical products, and various other 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.

[0061] The thickness of the film of the present invention can be set depending on the application, but for example, for general packaging, release agents, agricultural, forestry, and fisheries applications in which it is used in sheet form, 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, it is preferably 10 μm or more and 300 μm or less from the viewpoint of processability and handleability, 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.

[0062] <Film Having a 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. For example, the functional layer may be laminated by vapor deposition, sputtering, coating, various printing methods such as gravure printing and offset printing, thermal adhesion, or lamination via an adhesive layer. From the viewpoint of not impairing the effects of the present invention, the functional layer is preferably biodegradable or has 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 preferred 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.

[0063] When a vapor-deposited layer is laminated as a functional layer on the film of the present invention, it is preferable that the vapor-deposited layer be laminated on at least one side of the film. Furthermore, from the viewpoint of exhibiting gas barrier properties, 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 a "D layer"). 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 in a total amount exceeding 50% by mass, where the total amount 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 the D layer, from the viewpoints of improving adhesion to the film, improving gas barrier properties 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.

[0064] 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. By providing such a resin layer, effects such as improving the adhesion between the D layer and the film may be obtained. 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.

[0065]

[0023] Methods for forming the 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 not humidity-dependent and can exhibit excellent gas barrier properties even in a thin film. As the vapor deposition method, physical vapor deposition methods such as vacuum vapor deposition, EB vapor deposition, sputtering, and ion plating, and various chemical vapor deposition methods such as plasma CVD can be used, but vacuum vapor deposition is particularly preferred from the viewpoint of productivity.

[0066] 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.

[0067] When a functional layer such as a pressure-sensitive adhesive layer or a heat-sealing 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. As the resin component that can be used in Layer E, from the viewpoint of having high heat seal strength, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-methacrylic acid copolymer, etc., or any mixture thereof is preferably used. When multiple films are laminated, from the viewpoint of reducing the thickness of the final product, 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 any mixture thereof is preferably used. From the viewpoint of improving the biodegradability of the entire laminate, for example, resin components containing copolymer components of polyhydroxyalkanoic acid exemplified above, or biodegradable resins having a softening point or melting point lower than that of the aliphatic polyester film of the present invention, such as polylactic acid, polyglycolic acid, polybutylene succinate, or any mixture thereof is preferably used.

[0068] 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 suppressing a decrease in the biodegradability of the laminate and suppressing the thickness of the final product when multiple films are laminated.

[0069] 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.

[0070] As a method for forming the E layer on the aliphatic polyester film to form a laminate, coating or lamination is particularly preferred. As the coating method, bar coating, gravure coating, calendar coating, die coating, etc. can be used, and as the lamination method, dry lamination, solventless lamination, extrusion lamination, coextrusion, etc. can be used, but from the viewpoint of productivity, gravure coating, die coating, extrusion lamination, and coextrusion are more preferably used.

[0071] When the film of the present invention is laminated with a Y layer and a heat-sealable layer (E layer) as a functional layer, 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 quietness 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. As the resin component that can be used in the heat seal layer, from the viewpoint of having high heat seal strength, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-methacrylic acid copolymer, etc., or any mixture thereof is preferably used. When multiple films are laminated, from the viewpoint of reducing the thickness of the final product, 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 any mixture thereof is preferably used. From the viewpoint of increasing the biodegradability of the entire laminate, for example, a resin component containing a copolymer component of polyhydroxyalkanoic acid as the aliphatic polyester exemplified above, or a biodegradable resin having a softening point or melting point that is 20°C or more lower than that of the film of the present invention, such as polylactic acid, polyglycolic acid, polybutylene succinate, etc., or any mixture thereof is preferably used.

[0072] 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 viewpoint of achieving high heat seal strength and quietness, 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 suppressing a decrease in the biodegradability of the laminate and suppressing the thickness of the final product when multiple films are laminated.

[0073] <Packaging Material and Package> 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. In addition, it has excellent noise reduction properties, making it suitable for use in packaging snacks, etc., because it can suppress the rustling noise that occurs when touching or bending the packaging.

[0074] 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.

[0075] <Agricultural, forestry and fishery materials> The agricultural, forestry and fishery materials of the present invention will be described below. The agricultural, forestry and fishery materials of the present invention are 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 materials of the present invention are characterized by being biodegradable, and are 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.

[0076] <Coating Film for Agricultural, Forestry, and Fishery Materials> The aliphatic polyester film of the present invention can be used to coat agricultural, forestry, and fishery materials containing one or more selected from fertilizers, feed, seeds, and chemicals. This protects the coated agricultural, forestry, and fishery materials, preventing quality deterioration due to degradation and environmental pollution due to leakage, while biodegrading in soil or the ocean, allowing the fertilizer, feed, and chemicals to diffuse and disperse at an appropriate time, and 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 the 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.

[0077] As described above, by using the aliphatic polyester film of the present invention, which has excellent biodegradability and moderate processability, for this application, it is possible to prevent leakage of the agricultural, forestry, and fishery materials contained therein through pinholes, cracks, and areas of uneven coating thickness, and the thickness of the aliphatic polyester film of the present invention makes it possible to 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 makes it possible to promote crop growth simultaneously with germination.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] <Manufacturing Method> A preferred embodiment of the manufacturing method for the film of the present invention will be described below. As mentioned above, the film of the present invention preferably contains polyhydroxyalkanoic acid as the aliphatic polyester. The manufacturing method for the film of the present invention involves, in this order, a melting step in which the 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 layer structure of the aliphatic polyester film of the present invention is not particularly limited, and may be, 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, the Z layer refers to a layer different from the X layer and Y layer). The manufacturing method will be described in more detail below using an aliphatic polyester film having a single X layer structure, in which the X layer is made of polyhydroxyalkanoic acid, as an example, but the film of the present invention and its manufacturing method should not be construed as necessarily being limited thereto.

[0083] First, polyhydroxyalkanoic acid as an aliphatic polyester is melt-extruded through a single-screw extruder set at an extrusion temperature of 150°C to 220°C and passed through a filtration filter to remove foreign matter. The molten resin is then extruded through a slit-shaped die. From the perspective of easily controlling biodegradability, quietness, and breaking strength, it is more preferable to blend polyhydroxyalkanoic acid with another biodegradable resin having a higher glass transition temperature or melting point than polyhydroxyalkanoic acid, melt the blend in a single-screw extruder, and knead and mix the blend. Furthermore, it is preferable for the melt viscosity of the polyhydroxyalkanoic acid to be different from that of the other biodegradable resin having a higher glass transition temperature or melting point than polyhydroxyalkanoic acid, as this allows the two resins to disperse without completely mixing in the film, thereby facilitating the quiet effect. From this perspective, the melt viscosity of the polyhydroxyalkanoic acid is preferably at least 1.1 times, more preferably at least 1.2 times, and even more preferably at least 1.3 times the melt viscosity of the other biodegradable resin having a higher glass transition temperature or melting point than polyhydroxyalkanoic acid. There is no particular upper limit to the difference in melt viscosity, but from the viewpoint of obtaining appropriate dispersibility, it is preferably 2.0 times or less.

[0084] Furthermore, the water content of both the polyhydroxyalkanoic acid and the other biodegradable resin having a higher glass transition temperature or melting point than the polyhydroxyalkanoic acid is preferably 500 ppm or less by mass, more preferably 350 ppm or less, and even more preferably 200 ppm or less. If the water content of the resin exceeds 500 ppm, hydrolysis and transesterification may occur more easily in the extruder, and as hydrolysis progresses, resin deterioration may occur, resulting in a decrease in breaking strength. Furthermore, as the transesterification reaction progresses, both resins may become completely mixed in the film, making it difficult to achieve the quiet effect. The lower limit of the water content is not particularly limited, but is set to 50 ppm, which is the practical lower limit due to the pre-drying of the resin.

[0085] 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.

[0086] Next, the breaking strength and loss tangent 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, and these 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 may occur due to insufficient temperature. 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.

[0087] Thereafter, 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 lower than 1.5 times, oriented crystallization may be insufficient, making it difficult to obtain sufficient strength, while if the stretching ratio exceeds 10 times, excessive orientation may occur, making the film prone to rupture. From the above viewpoints, the uniaxial stretching ratio is preferably 2.0 to 7 times, and more preferably 2.5 to 5 times.

[0088] Next, the film uniaxially stretched in the longitudinal direction is introduced into a tenter while the ends of the film are held with clips, and while the ends of the film are held with clips, the film is preheated at a temperature of 50°C or higher and below the melting point of the polyhydroxyalkanoic acid, and then stretched (transversely stretched) at a ratio of 1.5 to 10 times in the width direction. If the preheating temperature is lower than 60°C, film rupture may occur due to insufficient temperature, and if the preheating temperature exceeds the melting point of the polyhydroxyalkanoic acid, orientation crystallization may be insufficient, making it difficult to obtain sufficient breaking strength. Furthermore, if the width direction stretching ratio is lower than 1.5 times, orientation crystallization may be insufficient, making it difficult to obtain sufficient breaking strength, and if the stretching ratio exceeds 10 times, film rupture may occur easily. From the above viewpoints, the preheating temperature of the tenter is preferably 55°C or higher and not higher than the melting point of the polyhydroxyalkanoic acid minus 5°C, and even more preferably 60°C or higher and not higher than the melting point of the polyhydroxyalkanoic acid minus 10°C. The stretching ratio in the width direction of the second axis is more preferably 2.0 times or more and 7 times or less, and even more preferably 2.5 times or more and 6 times or less.

[0089] Subsequently, by subjecting the film to a heat treatment and a relaxation treatment after the biaxial stretching, it is possible to control the elongation at break, the strength at break, and the thermal shrinkage rate. Specifically, it is preferable to subject the sequentially biaxially stretched film that has been stretched in the longitudinal and width directions to a relaxation treatment of 1% or more and 30% or less in the width direction by narrowing the width of the tenter rails, and more preferably 30% or less in the longitudinal direction by narrowing the tenter clip spacing, while heating the film to 100° C. or more and 100° C. or less and the melting point of the polyhydroxyalkanoic acid or less.

[0090] These relaxation treatments are preferably carried out continuously in a tenter after widthwise stretching, and preferably only in the widthwise direction. It is even more preferable to carry out the relaxation treatment simultaneously or continuously in both the longitudinal and widthwise directions. If the heating temperature during the relaxation treatment is less than 100°C, the structure of the film, which has become more oriented and crystallized after stretching, may not be sufficiently fixed, making it difficult to obtain sufficient breaking strength. If the temperature exceeds the melting point of the polyhydroxyalkanoic acid, the film may become loose, resulting in a decrease in breaking elongation and breaking strength, or the film may break. If the relaxation treatment in the widthwise direction is less than 1%, the heat shrinkage may become too large, and if it exceeds 30%, the film may become loose, resulting in a decrease in breaking elongation and strength. From the above perspectives, in the relaxation treatment of sequentially biaxially stretched films, the heating temperature is preferably 110°C or higher and the melting point of the polyhydroxyalkanoic acid minus 10°C or lower, and even more preferably 125°C or higher and the melting point of the polyhydroxyalkanoic acid minus 20°C or lower. The relaxation treatment is more preferably 3% or more and 20% or less, and even more preferably 5% or more and 15% or less.

[0091] In simultaneous biaxial stretching, the unstretched polyhydroxyalkanoic acid film may be continuously stretched in the longitudinal and transverse directions while being held at its edges by clips and introduced into a tenter, or may be simultaneously stretched in the longitudinal and transverse directions by being introduced into an oven as a sheet of unstretched polyhydroxyalkanoic acid film in a batchwise manner. In either case, as in sequential biaxial stretching, the film may be preheated at a temperature of 50°C or higher but lower than the melting point of polyhydroxyalkanoic acid while being held at its edges by clips, and then stretched in the longitudinal and transverse directions, followed by a relaxation treatment, which can also be used to control the heat yield and thickness unevenness.

[0092] The film of the present invention can be obtained by the stretching method exemplified above. Here, the area stretching ratio in the longitudinal direction and the width direction combined is preferably 2.2 times or more and 100 times or less. If the area stretching ratio is less than 2.2 times, oriented crystallization may be insufficient, resulting in poor thickness unevenness, while if the area stretching ratio exceeds 100 times, orientation may proceed excessively, 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.

[0093] Furthermore, the film of the present invention is preferably subjected to slight stretching by applying tension at a conveying speed in the subsequent winding process of 100.1% to 110.0% of the tenter outlet conveying speed after heat treatment and relaxation treatment. By applying tension to the partially loose amorphous molecular chains after relaxation treatment and slight stretching, it is possible to eliminate partially loosened areas in the film and achieve a uniform structure. Furthermore, if the conveying speed in the winding process is less than 100.1% of the tenter outlet speed, sufficient breaking strength cannot be obtained, resulting in insufficient processability, or a delay in biodegradation rate may occur. On the other hand, if the conveying speed in the winding process exceeds 110.0% of the tenter outlet speed, the thermal shrinkage rate may increase or the film may rupture. From the above viewpoints, the conveying speed in the winding process relative to the tenter outlet speed is more preferably 101.0% to 109.0%, and even more preferably 102.0% to 108.0%.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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-by-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.

[0099] Other methods for covering 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 to cover it; and a method in which the film is shrunk by reducing pressure to cover it.

[0100] 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 processability, biodegradability, and quietness.

[0101] <Biodegradation Method> The film of the present invention, and 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 warm at around 60°C to increase biodegradability, simple composting made by digging holes in the soil, composting containers that are partially or completely buried in the soil, small composting such as compost bags, and biological composting 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 being placed in composting equipment and subjected to a typical process, 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 and other 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 decomposition of the aliphatic polyester film of the present invention. 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.

[0102] 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. Evaluation of each item was carried out by the following methods. <Methods for measuring characteristic values ​​and methods for evaluating effects> The methods for measuring characteristic values ​​and evaluating effects in the present invention are as follows. (1) Film thickness evaluation The film thickness (unit: μm) was measured using a contact-type high-precision digital length measuring machine "Litematic VL50B" manufactured by Mitutoyo Corporation in an atmosphere of 23°C and 65% RH.

[0103] (2) Evaluation of loss tangent (tan δ) (2-1) Obtaining a loss tangent (tan δ) - temperature curve The film was cut into a rectangle of 50 mm length x 10 mm width in the longitudinal and transverse directions, and the sample was set in a dynamic viscoelasticity measuring device "EXSTAR DMS6100" manufactured by Seiko Instruments Inc. so that the long side direction was the tensile direction. Thereafter, under the conditions shown below, the atmosphere in the furnace in which the film was set was cooled with liquid nitrogen, and the temperature was raised from -70°C to 160°C for measurement, and a loss tangent (tan δ) - temperature curve was obtained by the dynamic viscoelasticity method. The temperature at which the measured loss tangent (tan δ) showed the maximum value was taken as the maximum peak temperature of tan δ. <Measurement conditions> Test mode: Tensile mode Chuck distance: 20 mm Frequency: 1 Hz Strain amplitude: 10.0 μm Gain: 1.5 Heating rate: 5°C / min

[0104] Figure 1 is an explanatory diagram illustrating a graph of the tan δ-temperature curve of an aliphatic polyester film. In Figure 1, reference numeral 1 denotes the maximum peak value of the loss tangent tan δ (A) in the range of more than -30°C and less than 30°C, reference numeral 2 denotes the loss tangent tan δ (30A) at 30°C, and reference numeral 3 denotes the loss tangent tan δ (-30A) at -30°C. Reference numeral 4 denotes the temperature T(A)°C at which tan δ (A) is obtained, and reference numeral 5 denotes the lower temperature T(L)°C at which tan δ (A) / 2 is obtained. Reference numeral 6 denotes the maximum peak value of the loss tangent tan δ (B) in the range of 40°C to 100°C.

[0105] (2-2) tan δ (A) / tan δ (30A) From the loss tangent (tan δ) - temperature curve obtained in (2-1), the maximum peak value of the loss tangent in the range of more than -30 ° C and less than 30 ° C was determined as tan δ (A), and the loss tangent at 30 ° C was determined as tan δ (30A). Note that tan δ (A) / tan δ (30A) in the present invention was measured three times in each of the longitudinal direction and the width direction, and the average value of a total of six tan δ (A) / tan δ (30A) values ​​was adopted. Here, for the maximum extreme value of the tan δ - temperature curve in the range of more than -30 ° C and less than 30 ° C (hereinafter referred to as the "maximum extreme value") and the minimum value of tan δ in the range of more than -30 ° C and less than 30 ° 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 of the loss tangent was observed, and tan δ (A) was absent. In addition, when it was determined that there was no tan δ(A) among the six measurements in total and tan δ(A) / tan δ(30A) could not be calculated, the average value of tan δ(A) / tan δ(30A) was calculated for the number of measurements for which it could be calculated.

[0106] (2-3) tan δ (A) / tan δ (-30A) From the loss tangent (tan δ) - temperature curve obtained in (2-1), the maximum peak value of the loss tangent in the range of more than -30 ° C and less than 30 ° C was determined as tan δ (A), and the loss tangent at -30 ° C was determined as tan δ (-30A). In addition, for tan δ (A) / tan δ (-30A) of the present invention, measurements were performed three times in each of the longitudinal direction and the width direction, and the average value of tan δ (A) / tan δ (-30A) for a total of six measurements was adopted. Here, for the maximum extreme value of the tan δ - temperature curve in the range of more than -30 ° C and less than 30 ° C and the minimum value of tan δ in the range of more than -30 ° C and less than 30 ° C, if the value obtained by dividing the maximum extreme value by the minimum value is less than 2.0, it is deemed that no peak of the loss tangent is observed, and it is determined that there is no tan δ (A). In addition, when it was determined that there was no tan δ(A) among the six measurements in total and tan δ(A) / tan δ(-30A) could not be calculated, the average value of tan δ(A) / tan δ(-30A) was calculated for the number of measurements for which it could be calculated.

[0107] (2-4) T(A) - T(L) From the loss tangent (tan δ) - temperature curve obtained in (2-1), the maximum peak value of the loss tangent in the range of more than -30 ° C and less than 30 ° C was defined as tan δ (A), the temperature at which the loss tangent showed tan δ (A) was defined as T(A) ° C, and the lower temperature among the temperatures at which the loss tangent became tan δ (A) / 2 was defined as T(L) ° C. The difference between T(A) and T(L) (T(A) - T(L)) ° C was calculated. Note that, for the present invention, T(A) - T(L) was measured three times in the longitudinal direction and width direction, and the average value of a total of six T(A) - T(L) values ​​was used. Here, for 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, if the value obtained by dividing the maximum extreme value by the minimum value is less than 2.0, it was determined that no peak in the loss tangent was observed and tan δ(A) was absent. Furthermore, when it was determined that tan δ(A) was absent and T(A)-T(L) could not be calculated out of a total of six measurements, the average value of T(A)-T(L) was calculated for the number of measurements for which it could be calculated.

[0108] (2-5) tan δ(B) / tan δ(A) From the loss tangent (tan δ)-temperature curve obtained in (2-1), the maximum peak value of the loss tangent in the range of more than -30 ° C. and less than 30 ° C. was defined as tan δ(A), and the maximum peak value of the loss tangent in the range of 40 ° C. or more and 100 ° C. or less was defined as tan δ(B), and the ratio of tan δ(A) to tan δ(B) (tan δ(B) / tan δ(A)) was calculated. Note that, for the present invention, tan δ(B) / tan δ(A) was measured three times in the longitudinal direction and three times in the width direction, and the average value of a total of six tan δ(B) / tan δ(A) was used. Here, for the maximum extreme value of the tan δ-temperature curve in the range of more than -30 ° C and less than 30 ° C, and the minimum value of tan δ in the range of more than -30 ° C and less than 30 ° C, if the value obtained by dividing the maximum extreme value by the minimum value is less than 2.0, no peak in the loss tangent was observed and it was determined that tan δ (A) was absent. Similarly, for the maximum extreme value of the tan δ-temperature curve in the range of 40 ° C or more and 100 ° C or less, and the minimum value of tan δ in the range of 40 ° C or more and 100 ° C or less, if the value obtained by dividing the maximum extreme value by the minimum value is less than 2.0, it was determined that tan δ (B) was absent. Furthermore, when it was determined that tan δ (A) and / or tan δ (B) were absent and tan δ (B) / tan δ (A) could not be calculated out of a total of six measurements, the average value of tan δ (B) / tan δ (A) was calculated for the number of measurements for which it could be calculated.

[0109] (3) Mechanical Property Evaluation (3-1) Breaking Strength S1 and S2 A rectangular sample was cut out, 150 mm long x 10 mm wide, with the machine direction (MD) in the film production process as the longitudinal direction and the direction perpendicular to the machine direction in the film production process (TD) as the width direction. The sample was placed in a tensile tester (Orientec Co., Ltd. "Tensilon Universal Tester" RTG-1210) with an initial chuck distance of 30 mm so that the long side was the tensile direction. A tensile test was performed at a tension rate of 300 mm / min in an atmosphere of 25±5°C and 65±10% RH. The maximum load at which the sample broke was read and divided by the cross-sectional area of ​​the sample before the test (film thickness × width determined in (1)) to calculate the breaking strength (unit: MPa). The same measurements were carried out five times for each sample in the longitudinal direction and the width direction, and the average breaking strength in the longitudinal direction was designated as S1 (MPa), and the average breaking strength in the width direction was designated as S2 (MPa).

[0110] (3-2) Determination of Samples with Unknown Orientation For films with unknown orientation, a rectangular sample of 150 mm long x 10 mm wide was cut with an arbitrary direction facing upward, and designated sample <1>. The direction of the long side of sample <1> was defined as 0°. Next, sample <2> of the same size was taken so that the long side direction was rotated 15° to the right from the 0° direction. Similarly, the long side direction of each rectangular sample was rotated 15° at a time, and samples <3> to <12> were similarly taken. Next, for each rectangular sample, the breaking strength was determined using the same procedure as in (3-1). The long side direction (main orientation axis direction) of the sample with the largest breaking strength was defined as the longitudinal direction in the present invention, and the direction perpendicular to the main orientation axis direction was defined as the width direction.

[0111] (4) Melt Viscosity Using a Capillograph (1D) manufactured by Toyo Seiki Seisakusho, polyhydroxyalkanoic acid was measured at a temperature of 160°C and a shear rate of 121 s -1 The conditions for resins other than polyhydroxyalkanoic acid are 190°C and 121 s -1 The melt viscosity (unit: Pa·s) of the resin was measured under the conditions above.

[0112] (5) Glass Transition Temperature Measurements and analysis were performed 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 was calculated using the following formula: Glass transition temperature = (extrapolated glass transition onset temperature + extrapolated glass transition end temperature) / 2 Here, the extrapolated glass transition onset temperature is the temperature at the intersection of a straight line extending the low-temperature baseline toward the high-temperature side and a tangent drawn at the point where the gradient of the curve of the stepwise change in the glass transition is maximum. The extrapolated glass transition end temperature is the temperature at the intersection of a straight line extending the high-temperature baseline toward the low-temperature side and a tangent drawn at the point where the gradient of the curve of the stepwise change in the glass transition is maximum.

[0113] (6) Content of polyhydroxyalkanoic acid resin and resin components other than polyhydroxyalkanoic acid: An 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, and the components constituting each layer were sampled and evaluated. In the examples and comparative examples, the composition was calculated from the mixing ratio during film production.

[0114] (7) Moisture Content (ppm) Using a Karl Fischer moisture meter (manufactured by HIRANUMA Corporation, model number AQ-7+EV-6) and "Aqualite RS-A" as a measurement reagent, the moisture content (ppm) of polyhydroxyalkanoic acid resins and resins other than polyhydroxyalkanoic acid was determined under heating conditions of 130°C and 15 minutes.

[0115] (8) Crystallite size (8-1) Acquisition of two-dimensional diffraction image A film sample was cut into a size of 2 cm in the longitudinal direction and 1 cm in the width direction, and a number of sheets with a total thickness of 100 μm or more were directly stacked so that the longitudinal direction was the same, and the sample was fixed to a holder so that X-rays were incident on the center of the sample in a direction perpendicular to the longitudinal direction, and then reflection measurement in the film thickness direction was performed under the following conditions to obtain a two-dimensional X-ray diffraction image. Apparatus: Bruker AXS D8 DISCOVER μHR Hybrid X-ray source: CuKα ray (using a multilayer mirror), wavelength λ = 0.15418 nm Output: 50 kV, 22 mA Slit system: (X-ray source side) 1 mm 2 -1 mm 2 -0.1 mm Φ (sample side) Detector: two-dimensional detector (Vantec500) Scan: 2θ=20° Elevation angle: ω=10° Camera length: 10 cm Integration time: 300 seconds / frame.

[0116] (8-2) Orientation Profile From the diffraction image obtained in (8-1), the diffraction angle (2θ) was scanned in the range of 19° or more and 21° or less in increments of 0.5° at a circular angle of 40° to 140° with 90° as the thickness direction, and the scanned results were integrated to obtain an orientation profile.

[0117] (8-3) Orientation angle, degree of orientation A baseline was set at the minimum value of the orientation profile obtained in (8-2), 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 degree of orientation of PB was calculated from the half-width HO of the peak using the following formula: Orientation degree = (180 - HO) / ​​180.

[0118] (8-4) 2θ Profile in Orientation Direction The range of the orientation angle determined from (8-3) ±10° was scanned in 0.05° increments, and the results were integrated to obtain a 2θ profile.

[0119] (8-5) Crystallite Size A baseline was set at the minimum value of the 2θ profile obtained in (8-4), and the peak with the highest intensity was separated from the peaks with an orientation degree of 0.50 or more in the diffraction angle (2θ) range of 19° to 21° using a Gaussian distribution function. The crystallite size (nm) was calculated from the half-width of the separated peak using the Scherrer formula. The Scherrer constant was set to 0.9, and the half-width correction value was calculated from the Si diffraction peak (111) measured using standard Si powder for X-ray diffraction manufactured by NIST under the conditions and equipment described in (8-1).

[0120] (9) 120°C Heat Shrinkage Rates Y1 and Y2 The film is cut into a rectangle of 150 mm length x 10 mm width in the longitudinal and transverse directions, and a mark is made in the central 100 mm area with an oil-based marker. The length is measured using a universal projector to determine the initial length I0. The measured sample is then placed in a gear-type hot air oven adjusted to 120°C, and a 2.1 g load is attached to the bottom of the hanging film. The gear is rotated while the oven is heat-treated for 15 minutes. The film is then removed and cooled to room temperature, and the length between the marks is measured using a universal projector to determine the heat shrinkage I0. H Measured length I0 and I H The 120°C heat shrinkage (unit: %) was calculated from the following formula (I). The same measurement was carried out five times in the longitudinal direction and width direction of each sample, and the average value in the longitudinal direction was taken as Y1 (%), and the average value in the width direction was taken as Y2 (%). 120°C heat shrinkage (%) = (I0 - I H ) / I0×100...(I)

[0121] (10) Thickness irregularities X1 and X2 Five arbitrary points were randomly selected in the film and marked, and the film thickness was measured at 1 cm intervals from each mark in the longitudinal direction and 15 cm in the transverse direction, respectively, according to the method in (1). Then, the average values ​​of the film thicknesses at a total of 31 points in the longitudinal direction and transverse direction were calculated as T. AV , the maximum value is T MAX , the minimum value is T MINThe thickness unevenness (unit: R%) was calculated from the measured film thickness using the following formula (II). The same measurement was performed on five selected locations on each sample, and the average value in the longitudinal direction was taken as thickness unevenness X1 (R%), and the average value in the width direction was taken as thickness unevenness X2 (R%). Thickness unevenness (R%) = (T MAX -T MIN ) / T AV ×100...(II)

[0122] (11) Puncture Evaluation (11-1) Puncture Strength (20 μm Equivalent Value) (10) As in the procedure, a mark was made at any point on the film, and the film thickness was measured at 3 cm intervals from the mark in the longitudinal direction, and 15 cm from the mark in the width direction. Then, for a total of 21 film thickness measurements in the longitudinal and width directions, in accordance with JIS Z1707 (2019), the puncture strength (Force; unit gf) of the film was measured under the following conditions using a "HANDY-TYPE COMPRESSION TESTER" KES-G5 manufactured by KATOTECH Co., Ltd. Each measured value was divided by the film thickness (μm) and then multiplied by 20 (μm), and the average value was adopted as the puncture strength (20 μm equivalent value). <Measurement conditions> SENS: 10 SPEED: 0.20 cm / sec STROKE: 20 mm / 10V Needle diameter: 1.0 mmφ Hole diameter: 10.0 mmφ

[0123] (11-2) Coefficient of variation of puncture strength (20 μm equivalent value) The average value of the puncture strength measured in (11-1) is P AV When the standard deviation of the total 21 points was taken as σ, the coefficient of variation of the puncture strength was calculated using the following formula (V): Coefficient of variation (%) = σ / P AV ×100...(V).

[0124] (12) Raman Orientation Parameter (Fa-Fb) (12-1) Cross-Section Evaluation of Polarized Raman Spectra Film samples were fixed so that the direction perpendicular to the thickness direction in the cross section was the measurement direction, embedded in UV-curable resin, and the cross section was cut using a microtome. Two types of samples were prepared: one with the longitudinal direction as the measurement direction, and the other with the width direction as the measurement direction. Each sample was fixed on a cross-section observation stage, and Raman spectra were measured in two directions of polarization axes by irradiating the cross section with a laser whose polarization axis was in the film plane direction and a laser whose polarization axis was in the film thickness direction under the following conditions. Apparatus: Renishaw InVia Conditions: Microscopic Raman measurement mode Objective lens: 50x Beam diameter: 2 µm Light source: Semiconductor laser 532 nm Laser power: 300 mW Diffraction grating: Single 1800, 3000 gr / mm Slit: 65 µm Detector: Renishaw CCD 1024 x 256.

[0125] (12-2) Calculation of Fa and Fb The peak due to C═O stretching vibration (1720 cm -1 near 1450 cm ) and a peak due to C-H bending vibration ( -1 The longitudinal orientation parameter Fma and the width orientation parameter Fta were determined from the intensity ratio (peak intensity due to C=O stretching vibration / peak intensity due to C-H deformation vibration) of the peak (near 875 cm) due to C-C stretching vibration in the Raman spectrum obtained in (12-1), and the average value Fa was calculated using the following formula. -1 near 1770 cm ) and a peak due to C═O stretching vibration (1770 cm ). -1The longitudinal orientation parameter Fmb and the width orientation parameter Ftb were determined from the intensity ratio (peak intensity due to C-C stretching vibration / peak due to C=O stretching vibration) of the peaks (near the longitudinal direction) (peak intensity due to C-C stretching vibration / peak due to C=O stretching vibration), and the average value of these was calculated using the following formula. For the measurement, three cross-section cut samples were prepared in advance for each direction, and the average value of these measurement results was used. <Fa=(Fma+Fta) / 2> Fma is calculated using the formula: the intensity ratio in the direction parallel to the film surface in the longitudinal cross section (MD) divided by the intensity ratio in the thickness direction (ZD) in the same cross section. Fma=((I1720m) MD / (I1450m) MD ) / ((I1720m) ZD / (I1450m) ZD ) (I1720m) MD : Peak derived from C═O stretching vibration in the film plane direction in the longitudinal cross section (1720 cm -1 Nearby) Intensity (I1450m) MD : Peak derived from C—H bending vibration in the film plane direction in the longitudinal cross section (1450 cm -1 Nearby) Intensity (I1720m) ZD : Peak due to C═O stretching vibration in the thickness direction of the longitudinal cross section (1720 cm -1 Nearby) Intensity (I1450m) ZD : Peak due to C—H bending vibration in the thickness direction of the longitudinal cross section (1450 cm -1 The strength Fta is calculated by dividing the strength ratio (TD) in the direction parallel to the film surface in the width direction cross section by the strength ratio (ZD) in the thickness direction in the same cross section. Fta = ((I1720t) TD / (I1450t) TD ) / ((I1720t) ZD / (I1450t) ZD ) (I1720t) TD : Peak derived from C═O stretching vibration in the film plane direction in the width direction cross section (1720 cm -1 Nearby) Intensity (I1450t) TD : Peak derived from C—H bending vibration in the film plane direction in the width direction cross section (1450 cm -1 Nearby) Intensity (I1720t) ZD: Peak due to C═O stretching vibration in the film thickness direction in the width direction cross section (1720 cm -1 Nearby) Intensity (I1450t) TD : Peak derived from C—H bending vibration in the film thickness direction in the width direction cross section (1450 cm -1 Fmb is calculated by dividing the strength ratio (MD) in the direction parallel to the film surface in the longitudinal cross section by the strength ratio (ZD) in the thickness direction in the same cross section. Fmb=((1875m) MD / (I1770m) MD ) / ((I875m) ZD / (I1770m) ZD ) (I875m) MD : Peak derived from C-C stretching vibration in the film plane direction in the longitudinal cross section (875 cm -1 Nearby) Intensity (I1770m) MD : Peak derived from C═O stretching vibration in the film plane direction in the longitudinal cross section (1770 cm -1 Nearby) Intensity (I875m) ZD : Peak derived from C-C stretching vibration in the film thickness direction in the longitudinal cross section (875 cm -1 Nearby) Intensity (I1770m) ZD : Peak due to C═O stretching vibration in the film thickness direction in the longitudinal cross section (1770 cm -1 The strength Ftb is calculated by dividing the strength ratio (TD) in the direction parallel to the film surface in the width direction cross section by the strength ratio (ZD) in the thickness direction in the same cross section. Ftb = ((I875t) TD / (I1770t) TD ) / ((I875t) ZD / (I1770t) ZD ) (I875t) TD : Peak derived from C-C stretching vibration in the film plane direction in the width direction cross section (875 cm -1 Nearby) Intensity (I1770t) TD : Peak derived from C═O stretching vibration in the film plane direction in the width direction cross section (1770 cm -1 Nearby) Intensity (I875t) ZD: Peak derived from C-C stretching vibration in the film thickness direction in the width direction cross section (875 cm -1 Nearby) Intensity (I1770t) ZD : Peak due to C═O stretching vibration in the film thickness direction in the width direction cross section (1770 cm -1 Neighborhood) Intensity

[0126] (13) Biodegradability of Film One liter of wet synthetic compost was prepared according to JIS K6954 (2008) and placed in a polypropylene container with a capacity of 10 liters. Next, a 5 cm x 5 cm piece of evaluation film was cut out and sandwiched between a polyethylene holder with a 2 cm square cutout on the inside, so that the film inside the holder was exposed to the outside through the 2 cm square cutout.

[0127] The film sample, fixed with a holder, was then placed in the moist synthetic compost in a polypropylene container, and a 60-day incubation test was conducted in an oven controlled at 28±2°C according to JIS K6954 (2008). When the film sample was placed, the entire 2 cm square exposed film area in the holder was covered with moist synthetic compost. After the initial placement, the film sample was removed every two days, the moist synthetic compost was stirred with a scoop, and the film sample was then placed again. This process was repeated.

[0128] After 60 days had passed since the initial addition, the film sample was removed from the container and photographed with a digital camera. The number of pixels in the photograph was set to 1200 dpi (2 million pixels) or more. From the photograph, the area of ​​the sample remaining within a 2 cm square frame inside the holder was determined, and the collapsed area ratio (%) was calculated using the formula (initial area of ​​the sample in the holder - remaining area of ​​the sample in the holder) / (initial area of ​​the sample in the holder) x 100. A total of three holders were evaluated in the same compost, and the arithmetic mean value of the three measurements was taken as the collapsed area ratio (%) of the film sample, and was judged according to the following criteria. The biodegradability of the film is preferably C or higher. A: Collapsed area ratio is 30% or more B: Collapsed area ratio is 15% or more but less than 30% C: Collapsed area ratio is 5% or more but less than 15% D: Collapsed area ratio is less than 5%

[0129] (14) Processability A 300 mm wide, 200 m long film was prepared and wound around a 6 inch, 350 mm long core. The film was rewound around the same 6 inch, 350 mm long core at a conveying tension of 50 N / m. The conveying speed at which tearing occurred was used to evaluate the processability of the film as follows. Film processability of C or higher is preferable. A: No tearing occurred even when rewound at a conveying speed of 10 m / min. B: No tearing occurred even when rewound at a conveying speed of 7 m / min, but tearing occurred when the conveying speed was changed to 10 m / min. C: No tearing occurred even when rewound at a conveying speed of 5 m / min, but tearing occurred when the conveying speed was changed to 7 m / min. D: Tearing occurred when rewound at a conveying speed of 5 m / min.

[0130] (15) Processability of Film at High Temperature and High Speed ​​A 300 mm wide, 200 m long film wound around a 6-inch, 350 mm long core was prepared, and passed through an infrared continuous oven having one chamber (1 m long) maintained at 120°C and two chambers (1 m long) maintained at 40°C under a conveying tension of 50 N / m. The film was then rewound onto the same 6-inch, 350 mm long core. The processability of the film at high temperature and high speed was evaluated based on the conveying speed at which tearing occurred, as follows: A: No tearing occurred even when rewinding at a conveying speed of 8 m / min. B: No tearing occurred even when rewinding at a conveying speed of 6 m / min, but tearing occurred when the conveying speed was changed to 8 m / min. C: No tearing occurred even when rewinding at a conveying speed of 4 m / min, but tearing occurred when the conveying speed was changed to 6 m / min. D: Tearing occurred when rewinding at a conveying speed of 4 m / min. A film's processability at high temperature and high speed is preferably C or higher.

[0131] (16) Barrier properties of film (16-1) Vapor deposition of Al on film The film was set in a vacuum deposition device equipped with a film running device, and -2After the vacuum deposition apparatus was set to a highly reduced pressure 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 with a thickness of 100 nm on the surface of the film that had been in contact with the casting drum during the film-forming process. Thereafter, the pressure inside the vacuum deposition apparatus was returned to normal pressure, and the wound film was rewound and aged at a temperature of 40°C for 2 days to obtain a laminate in which a vapor-deposited layer of Al (aluminum) was laminated on the film.

[0132] (16-2) Evaluation of Barrier Properties of Films The laminates in (16-1) in which Al (aluminum) was laminated as a barrier layer were measured using a water vapor transmission rate measuring device "PERMATRAN-W" (registered trademark) 3 / 30 manufactured by MOCON / Modern Controls under conditions of a temperature of 40°C and a humidity of 90% RH. The measurement was carried out five times in total at an arbitrary location on the film and at positions 10 cm before and after that in the longitudinal and width directions, and the average of the obtained values ​​was calculated to be the water vapor transmission rate of the film (unit: g / m 2 / day). From the obtained water vapor transmission rate, the barrier properties of the film were evaluated as follows: A: 50 g / m 2 / day or less B: 50g / m 2 / day and above 60g / m 2 / day or less B - : 60 g / m 2 / day or more than 75g / m 2 / day or less C: 75g / m 2 / day and greater than 100g / m 2 / day or less D: 100g / m 2 The barrier property of the film is preferably C or higher.

[0133] (17) Quietness of Film (Measurement of Noise Level) The quietness of the film was measured and evaluated by the following method using a set of omnidirectional microphones (½-inch electric microphone (UC-53A), preamplifier (NH-22)) and FFT analyzer (SA-78) manufactured by Rion Co., Ltd., and waveform analysis software (CAT-WAVE) and Gelbot tester (specified in ASTM F-392) manufactured by Catec Co., Ltd.

[0134] An A4-sized sample was cut so that the MD direction was aligned with the long side of the film. Both ends of the short side of the A4-cut sample were attached to the sample holder of the Gelbot tester with double-sided tape, and a 30-second cyclic fatigue test was performed at room temperature. The sound emitted during the test was collected using omnidirectional microphones (UC-53A and NH-22) and an SA-78 set 5 cm away from the center of the film, and waveform data was obtained. The waveform data was subjected to FFT transformation using a CAT-WAVE to obtain the noise level (dB). Similar measurements were performed three times, and the average value obtained was used as the film's noise level (dB) and as an index for evaluating its quietness. The film's quietness was measured in a soundproof room to block external noise, and sound-absorbing material (foamed PE) was attached to the walls of the Gelbot tester to suppress sound reverberation within the tester. The measurement conditions for the SA-78 and the analysis conditions for the CAT-WAVE were as follows: <FFT analyzer (SA-78)> ・Calibration setting 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: 20,000 Hz Number of analysis points: 4,096 Time window function: Rectangular Averaging method: Frequency [Automatic] 1,600 points in 12.5 Hz increments Measurement range: 14 cycles, 20.2 seconds (1 cycle is calculated at approximately 1.44 seconds) A-weighted noise level The quietness was judged according to the following criteria. Quietness of C or higher is preferable. A: Noise level is less than 80 dB, very quiet. B: Noise level is 80 dB or more but less than 85 dB, excellent quietness. C: Noise level is 85 dB or more but less than 90 dB, poor quietness but practically usable. D: Noise level is 90 dB or more, very poor quietness.

[0135] (18) Heat sealability A laminate having a Y layer laminated thereon as a heat seal layer was cut into a plurality of pieces each having a size of 10 cm in the width direction and 20 cm in the length direction. Next, the cut-out laminates were stacked so that the heat seal layer and the opposite side thereof faced each other, and the heat sealability was measured 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 The film was heat-sealed in the width direction for a sealing time of 1 second. Next, the heat-sealed laminate was placed on the opposite side of the heat-sealed laminate so that the heat-sealed layer of the third cut-out laminate overlapped the heat-sealed layer of the third cut-out laminate, and heat-sealed in the same manner as above. A total of seven cut-out laminates were successively heat-sealed in the same manner. The sealing quality of the film was judged as follows based on the number of laminates that showed visually noticeable deterioration in quality, such as wrinkles or bubbles, in the heat-sealed area during heat sealing. Starting with two sheets, heat sealing was performed at five locations at 3 cm intervals in the longitudinal direction, and the number of sheets that showed the least deterioration in quality was adopted. The sealing quality of the film is preferably C or higher. A: No deterioration in quality even with 7 sheets B: Deterioration in quality with 5 to 6 sheets C: Deterioration in quality with 3 to 4 sheets D: Deterioration in quality with 2 sheets

[0136] [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 may be referred to as "PHA." PHA: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) "BP350-05" manufactured by Blue Crystal Microorganisms. PLA-1: Polylactic acid "LX175" manufactured by Total Energy Corbion, D-unit content 4%. PLA-2: Polylactic acid "LX975" manufactured by Total Energy Corbion, D-unit content 12%.

[0137] Example 1 PHA was fed into a single-screw melt extruder as a resin raw material for an aliphatic polyester. After melt extrusion at 170°C, the extruded molten resin was filtered through a 250 μm mesh filter to remove foreign matter. The molten resin was then guided to a T-die and extruded into a sheet. The extruded molten resin sheet was cooled and solidified on a casting drum maintained at 25°C to obtain an unstretched sheet.

[0138] Next, the unstretched sheet was introduced into an MD stretching process consisting of a continuous roll group, preheated to 30°C for 100 seconds using a plurality of rolls, then held at 152°C for 1 second and passed through rolls with a peripheral speed difference, and stretched 2.8 times in the longitudinal direction. The stretched film was then passed through 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 100°C while both widthwise ends were held with clips, stretched 3.3 times in the widthwise direction at 100°C, and then heat-treated at 120°C while providing 10% 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 to the outside of the tenter, and the clips at both widthwise ends were released. Furthermore, the ratio of the conveying speed of the subsequent winder process to the tenter outlet conveying speed was set to 105.0%, and the film was conveyed while applying tension in the MD to slightly stretch it. Then, a 20 μm thick aliphatic polyester film was wound into a roll using a winding machine. The properties of the obtained aliphatic polyester film are shown in Table 1.

[0139] Examples 2 to 4 Aliphatic polyester films were obtained in the same manner as in Example 1, except that the film-forming conditions, such as the stretching ratio, the ratio of the conveying speed in the winder process to the tenter outlet speed, and the relaxation treatment ratio, were changed as shown in Table 1.

[0140] Example 5: 70% by mass of PHA as an aliphatic polyester resin raw material and 30% by mass of PLA-1 as a resin raw material other than PHA were blended and fed to a single-screw melt extruder. After melt extrusion at an extruder temperature of 170 ° C, foreign matter was removed from the extruded molten resin using a 250 μm cut mesh filter. The mixture was then introduced into a T-die and discharged into a sheet. The discharged molten sheet was cooled and solidified on a casting drum maintained at 25 ° C to obtain an unstretched sheet.

[0141] Next, the unstretched sheet was introduced into an MD stretching process consisting of a continuous roll group, preheated to 30°C for 60 seconds using a group of rolls, then held at 65°C for 1 second and passed through rolls with a peripheral speed difference, and stretched 3.0 times in the longitudinal direction. The stretched film was then passed through 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 4.0 times in the widthwise direction at 75°C, and then heat-treated at 120°C while providing 10% relaxation in the widthwise direction. The film was then guided outside the tenter after a cooling process at 50°C while continuing to tentatively hold both widthwise ends with clips, and the clips at both widthwise ends were released. The ratio of the conveying speed of the next winder process to the tenter outlet conveying speed was set to 105.0%, and the film was conveyed while applying tension in the MD and undergoing slight stretching. The aliphatic polyester film was then wound into a roll with a thickness of 20 μm using a winding machine. The properties of the resulting aliphatic polyester film are shown in Table 2.

[0142] Aliphatic polyester films were obtained in the same manner as in Example 5, except that the raw material compositions and film-forming conditions were changed as shown in Tables 2, 3, and 4. The properties of the obtained aliphatic polyester films are shown in Tables 2, 3, and 4.

[0143] (Examples 13 and 14, Comparative Example 5) In Example 13, the film of Example 1 (X layer) was used; in Example 14, the film of Example 5 (X layer); and in Comparative Example 5, the film of Comparative Example 1 (X layer) were used; the heat sealing agent "Seikadyne" (registered trademark) BP-1910W manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. was applied as a Y layer to the surface of the film that had been in contact with the casting drum in the film-forming process by gravure coating, with the coating amount adjusted to a thickness of 1 μm, to obtain a laminate film. The properties of the obtained laminate films containing the X layer and Y layer containing aliphatic polyester are shown in Table 5.

[0144]

[0145]

[0146]

[0147]

[0148]

[0149] The present invention can provide a film containing an aliphatic polyester that is excellent in processability, biodegradability, and noise reduction, and can be suitably used for packaging applications and agricultural, forestry, and fisheries applications.

[0150] 1: Maximum peak value of loss tangent tanδ (A) in the range exceeding -30°C and less than 30°C 2: Loss tangent tanδ (30A) at 30°C 3: Loss tangent tanδ (-30A) at -30°C 4: Temperature T(A) °C showing tanδ (A) 5: Temperature T(L) °C on the lower side of the temperatures at which tanδ (A) / 2 is obtained 6: Maximum peak value of loss tangent tanδ (B) in the range of 40°C or higher and 100°C or lower

Claims

1. A film containing an aliphatic polyester, which has at least one loss tangent peak in the temperature range of from above -30°C to below 30°C, and where tan δ(A) is the maximum peak value of the loss tangent in the temperature range of from above -30°C to below 30°C and tan δ(30A) is the loss tangent at 30°C, tan δ(A) and tan δ(30A) satisfy formula (1): tan δ(A) / tan δ(30A)≧1.05...formula (1).

2. The aliphatic polyester film according to claim 1, wherein, when the thermal shrinkage rate at 120°C in the longitudinal direction is Y1 (%) and the thermal shrinkage rate at 120°C in the transverse direction is Y2 (%), both Y1 and Y2 are 15% or less, and when the thickness unevenness in the longitudinal direction is X1 (R%) and the thickness unevenness in the transverse direction is X2 (R%), both X1 and X2 are 0.1R% or more and 20R% or less. The thickness unevenness X1 and X2 (unit: R%) are calculated by dividing the average measured film thickness by T. AV , the maximum value is T MAX , the minimum value is T MIN The thickness unevenness (R%) is calculated from the following formula (2): MAX -T MIN ) / T AV ×100...Formula (2) 3. The aliphatic polyester film according to claim 1 or 2, having a tan δ(30A) 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.

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

5. The aliphatic polyester film according to claim 1 or 2, wherein tan δ(A) and tan δ(-30A) satisfy the following formula (3), where tan δ(A) is the loss tangent at -30°C and tan δ(-30A): tan δ(A) / tan δ(-30A)≧2.0 6. The aliphatic polyester film according to claim 1 or 2, wherein T(A) °C is the temperature at which the loss tangent is tan δ(A) and T(L) °C is the lower of the temperatures at which the loss tangent is tan δ(A) / 2, and T(A) and T(L) satisfy formula (4): T(A) - T(L) ≦ 35... formula (4).

7. The aliphatic polyester film according to claim 1 or 2, further comprising at least one loss tangent peak in the temperature range of 40°C to 100°C, wherein tan δ(A) and tan δ(B) satisfy the following formula (5): 0.8≦tan δ(B) / tan δ(A)≦10 8. The aliphatic polyester film according to claim 1 or 2, 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 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.

9. The aliphatic polyester film according to claim 1 or 2, wherein S1 (MPa) is the breaking strength in the machine direction and S2 (MPa) is the breaking strength in the width direction, and S1 and S2 satisfy the following formulas (6) and (7): 30≦S1≦280 (6) 30≦S2≦280 (7) 10. The aliphatic polyester film according to claim 1 or 2, having an average puncture strength (20 μm equivalent) of 80 gf or more and a coefficient of variation of the puncture strength (20 μm equivalent) of 30% or less.

11. The aliphatic polyester film according to claim 1 or 2, wherein the aliphatic polyester film contains polyhydroxyalkanoic acid, and the content of the polyhydroxyalkanoic acid is 45% by mass or more relative to 100% by mass of the total mass of the aliphatic polyester film.

12. The aliphatic polyester film according to claim 1 or 2, wherein Fa is the average of the longitudinal orientation parameter (I1720m / I1450m) and the width orientation parameter (I1720t / I1450t), and Fb is the average of the longitudinal orientation parameter (I875m / I1770m) and the width orientation parameter (I875t / I1770t), as determined by cross-sectional observation in Raman spectroscopy evaluation, and Fa and Fb satisfy formula (8): 0.6≦(Fb−Fa)≦2.5 13. The aliphatic polyester film according to claim 1 or 2, further comprising a functional layer on at least one surface thereof.

14. A package comprising the aliphatic polyester film according to claim 1 or 2.

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

16. The aliphatic polyester film according to claim 1 or 2, which is a film used to cover agricultural, forestry and fishery materials, the agricultural, forestry and fishery materials including one or more selected from fertilizers, feeds, seeds and seedlings, and medicines.

17. Agricultural, forestry and fishery materials characterized by being covered with the aliphatic polyester film according to claim 1 or 2.

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