Resin composition for film molding, film and laminate

Abstract

A resin composition for film molding, which contains a poly (3-hydroxyalkanoate)-based resin (A) and a polylactic acid-based resin (B). The content of the polylactic acid resin (B) is from 20% by weight to 65% by weight (inclusive) with respect to the total amount of the poly (3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B), and the content of the fatty acid amide (C) is from 0 part by weight to less than 0.5 part by weight with respect to 100 parts by weight of the poly (3-hydroxyalkanoate) resin (A). The total content of the poly (3-hydroxyalkanoate)-based resin (A) and the polylactic acid-based resin (B) in the total amount of the resin composition for film molding excluding the inorganic filler is 98.5% by weight or more.

Description

Technical Field

[0001] The present invention relates to a resin composition for film molding containing a poly(3-hydroxyalkanoate) resin, and a film and a laminate containing the composition. Background Art

[0002] In recent years, environmental problems caused by waste plastics have attracted much attention. Among them, marine pollution caused by waste plastics is serious, and the spread of biodegradable plastics that can be decomposed in the natural environment is expected.

[0003] As such biodegradable plastics, various plastics are known. In particular, poly(3-hydroxyalkanoate) resins (hereinafter sometimes referred to as P3HA resins) are thermoplastic polyesters produced and accumulated as energy storage substances in the cells of multiple microbial species, and are materials that can be biodegradable not only in soil but also in seawater. Therefore, they have attracted attention as raw materials for solving the above problems.

[0004] However, it is known that P3HA resins are materials with slower crystallization than ordinary thermoplastic resins. Therefore, when compounding P3HA resins with other resins and additives or performing film molding, there is a problem that curing after heating and melting is difficult to carry out.

[0005] Then, a technique for improving the curability of P3HA resins by blending a crystallization nucleating agent that promotes the crystallization of P3HA resins is known. As one of such crystallization nucleating agents, fatty acid amides have been reported (for example, refer to Patent Document 1). In the examples of this document, 1 to 5 parts by weight of fatty acid amide was blended relative to 100 parts by weight of the P3HA resin.

[0006] In addition, Patent Document 2 describes an example in which a resin composition obtained by blending a P3HA resin with other biodegradable resins contains montanic acid amide, which is an example of a fatty acid amide, as a lubricant. In this example, 0.5 parts by weight of montanic acid amide was blended relative to 100 parts by weight of the P3HA resin. montanic acid amide. <​​​​​​​​​​​​​​​​​

[0012] In P3HA-based resins, add yam When a film is formed using acid amide, if the surface of the resulting film is printed, the printing ink may be rejected; if aluminum or other materials are vapor-deposited onto the surface of the film, the adhesion of the vapor-deposited layer may be insufficient.

[0013] In response, the inventors of this application reduced the amount of fatty acid amides described in Patent Documents 1 and 2, resulting in improved printability and vapor deposition properties. However, with the reduction of fatty acid amides, curing after heating and melting becomes difficult, sometimes leading to difficulties in compounding and film forming, and a significant decrease in productivity.

[0014] In view of the above, the object of the present invention is to provide a resin composition for film forming, which contains a poly(3-hydroxyalkanoate) resin that can take into account both curability after heating and melting, as well as printability and / or vapor deposition properties.

[0015] Problem Solving Methods

[0016] To solve the above problems, the inventors conducted in-depth research and found that by reducing the amount of fatty acid amide added to a poly(3-hydroxyalkanoate) resin composition and adding a given amount of polylactic acid resin, it is possible to balance the curability after heating and melting, as well as the printability and / or vapor deposition properties, thereby completing the present invention.

[0017] That is, the present invention relates to a resin composition for film forming, comprising a poly(3-hydroxyalkanoate) resin (A) and a polylactic acid resin (B).

[0018] The content of the polylactic acid resin (B) in the total amount of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 20% by weight or more and 65% by weight or less.

[0019] Relative to 100 parts by weight of the above-mentioned poly(3-hydroxyalkanoate) resin (A), the content of fatty acid amide (C) is 0 parts by weight or more and less than 0.5 parts by weight.

[0020] The total content of the above-mentioned poly(3-hydroxyalkanoate) resin (A) and the above-mentioned polylactic acid resin (B) is 98.5% by weight or more in the total amount of the film-forming resin composition excluding inorganic fillers.

[0021] In addition, the present invention relates to a membrane having the above-described composition.

[0022] In addition, the present invention also relates to a laminate comprising a first resin layer as the above-mentioned film and a second resin layer laminated thereon.

[0023] The effects of the invention

[0024] According to the present invention, a resin composition for film forming can be provided, which contains a poly(3-hydroxyalkanoate) resin and can achieve both curability after heating and melting, as well as printability and / or vapor deposition properties.

[0025] According to a suitable method of the present invention, a film can be formed by heating and melting the above-mentioned film-forming resin composition, and the forming speed at this time can be increased.

[0026] Furthermore, according to a suitable method of the present invention, the stretching of the above-described film can be carried out continuously and stably. Moreover, a high-quality stretched film without stretch unevenness can be obtained at a high stretching ratio.

[0027] Furthermore, according to a suitable method of the present invention, a transparent film can be obtained. Detailed Implementation

[0028] The embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

[0029] This embodiment relates to a resin composition for film forming, which contains a poly(3-hydroxyalkanoate) resin (A) and a polylactic acid resin (B).

[0030] [Poly(3-hydroxyalkanoate) resin (A)]

[0031] The poly(3-hydroxyalkanoate) resin (A) (hereinafter also referred to as P3HA-based resin (A)) can be a single poly(3-hydroxyalkanoate) resin or a mixture of two or more poly(3-hydroxyalkanoate) resins. However, from the viewpoint of easily balancing membrane strength and productivity, it is preferable to be a mixture of at least two poly(3-hydroxyalkanoate) resins with different types of monomers and / or different proportions of monomers.

[0032] The P3HA resin (A) is preferably a polymer having 3-hydroxyalkanoate units, and more particularly, preferably a polymer containing units represented by the following general formula (1).

[0033] [-CHR-CH2-CO-O-] (1)

[0034] In general formula (1), R represents C p H 2p+1 The alkyl group indicated is p, which represents an integer from 1 to 15. Examples of R include straight-chain or branched alkyl groups such as methyl, ethyl, propyl, methylpropyl, butyl, isobutyl, tert-butyl, pentyl, and hexyl. P is preferably 1 to 10, and more preferably 1 to 8.

[0035] As a P3HA-based resin (A), a poly(3-hydroxyalkanoate)-based resin produced by microorganisms is particularly preferred. In the poly(3-hydroxyalkanoate)-based resin produced by microorganisms, all 3-hydroxyalkanoate units are contained in the form of (R)-3-hydroxyalkanoate units.

[0036] The P3HA-based resin (A) preferably contains 50 mol% or more of 3-hydroxyalkanoate units (especially units represented by general formula (1)) of all constituent units, more preferably 60 mol% or more, and even more preferably 70 mol% or more. As a constituent unit of the polymer, the P3HA-based resin (A) may contain only one or more 3-hydroxyalkanoate units, and may also contain other units (e.g., 4-hydroxyalkanoate units, etc.) in addition to one or more 3-hydroxyalkanoate units.

[0037] The P3HA-based resin (A) is preferably a homopolymer or copolymer containing 3-hydroxybutyrate (hereinafter, sometimes referred to as 3HB) units (hereinafter, both polymers are also collectively referred to as "poly(3-hydroxybutyrate) resin"). In particular, the 3-hydroxybutyrate units are preferably all (R)-3-hydroxybutyrate units. In addition, the P3HA-based resin (A) is preferably a copolymer containing 3-hydroxybutyrate units and other hydroxyalkyl ester units.

[0038] Specific examples of poly(3-hydroxybutyrate) resins include: poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxypropionate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (abbreviated as P3HB3HV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (abbreviated as P3HB3HH), poly(3-hydroxybutyrate-co-3-hydroxyheptanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxynonanoate), poly(3-hydroxybutyrate-co-3-hydroxydecanoate), poly(3-hydroxybutyrate-co-3-hydroxyundecanoate), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (abbreviated as P3HB4HB). In particular, from the viewpoint of membrane productivity and mechanical properties, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) is preferred.

[0039] By changing the composition ratio of repeating units, the melting point and crystallinity can be altered, thereby changing physical properties such as Young's modulus and heat resistance. This allows for the application of properties between polypropylene and polyethylene. Furthermore, from the viewpoint of easy industrial production and useful plastics in terms of physical properties, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is particularly preferred. In particular, among poly(3-hydroxybutyrate) resins, which are prone to thermal decomposition at temperatures above 180°C, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) can lower the melting point, enabling molding and processing at low temperatures, which is preferred from this perspective.

[0040] Commercially available products of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) include KANEKA Co., Ltd.'s "KANEKA Biodegradable Polymer Green Planet" (registered trademark).

[0041] When the P3HA resin (A) comprises a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, from the viewpoint of balancing the strength and productivity of the obtained film, the average content ratio of 3-hydroxybutyrate units and other hydroxyalkanoate units to all monomer units constituting the P3HA resin (A) is preferably 3-hydroxybutyrate units / other hydroxyalkanoates = 99 / 1 to 80 / 20 (mol% / mol%), more preferably 97 / 3 to 82 / 18 (mol% / mol%), and even more preferably 95 / 5 to 85 / 15 (mol% / mol%).

[0042] The average content ratio of each monomer unit to all monomer units constituting the P3HA resin (A) can be determined by methods known to those skilled in the art, such as those described in paragraph

[0047] of International Publication No. 2013 / 147139. The average content ratio refers to the molar ratio of each monomer unit to all monomer units constituting the P3HA resin (A). In the case where the P3HA resin (A) is a mixture of two or more poly(3-hydroxyalkanoate) resins, it refers to the molar ratio of each monomer unit contained in the mixture as a whole.

[0043] Since P3HA-based resins (A) readily balance curability after heating and melting with film strength, it is preferable to contain at least a poly(3-hydroxyalkanoate) copolymer (A1). Furthermore, since curability after heating and melting can be further improved, in addition to copolymer (A1), it is more preferable to further contain poly(3-hydroxybutyrate) (A2). Hereinafter, (A1) and (A2) will be described separately.

[0044] [Poly(3-hydroxyalkanoate) copolymer (A1)]

[0045] As a poly(3-hydroxyalkanoate) copolymer (A1), a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units is particularly preferred. Among these, from the viewpoint of improving the curability after heating and melting, it is preferable to use a copolymer in which the content of other hydroxyalkanoate units is 1 mol% or more and less than 24 mol% in the total of 3-hydroxybutyrate units and other hydroxyalkanoate units.

[0046] In the copolymer (A1), the proportion of other hydroxyalkanoate units is preferably 3 to 20 mol%, more preferably 4 to 17 mol%, and even more preferably 5 to 14 mol%.

[0047] As copolymer (A1), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) is preferred, and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is particularly preferred.

[0048] The weight-average molecular weight of the copolymer (A1) is not particularly limited, but from the viewpoint of film strength, it is preferably 200,000 or more, more preferably 300,000 or more, and even more preferably 400,000 or more. The upper limit is not particularly limited, but from the viewpoint of productivity, it is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less.

[0049] It should be noted that the weight-average molecular weight of poly(3-hydroxyalkanoate) resins can be determined by conversion to polystyrene using a gel permeation chromatography system (Shimadzu Corporation HPLC GPC system) employing chloroform solution. Appropriate columns for determining weight-average molecular weight can be used as the chromatographic column in this gel permeation chromatography system.

[0050] As a poly(3-hydroxyalkanoate) copolymer (A1), a copolymer (A1-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units in a proportion of 1 mol% or more but less than 10 mol% is particularly preferred. By using such a copolymer, it is easy to balance the strength of the film and its curability after heating and melting.

[0051] In the copolymer (A1-1), the proportion of other hydroxyalkanoate units is preferably 3 to 9 mol%, more preferably 4 to 8 mol%, and even more preferably 5 to 7 mol%.

[0052] As copolymer (A1-1), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) is preferred, and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is particularly preferred.

[0053] The weight-average molecular weight of the copolymer (A1-1) is not particularly limited, but from the viewpoint of film strength, it is preferably 200,000 or more, more preferably 300,000 or more, and even more preferably 400,000 or more. The upper limit is not particularly limited, but from a production point of view, it is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less.

[0054] The poly(3-hydroxyalkanoate) copolymer (A1) can consist solely of copolymer (A1-1), or, in addition to copolymer (A1-1), may further contain copolymer (A1-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units in a proportion of 10 mol% or more but less than 24 mol% of other hydroxyalkanoate units. By combining copolymer (A1-1) and copolymer (A1-2), the strength of the film can be further improved.

[0055] In the copolymer (A1-2), the proportion of other hydroxyalkanoate units is preferably 10-20 mol%, more preferably 10-17 mol%, and even more preferably 10-14 mol%.

[0056] As copolymer (A1-2), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) or poly(3-hydroxybutyrate-co-4-hydroxybutyrate) is preferred, and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is particularly preferred.

[0057] The weight-average molecular weight of the copolymer (A1-2) is not particularly limited, but from the viewpoint of film strength, it is preferably 200,000 or more, more preferably 300,000 or more, and even more preferably 400,000 or more. The upper limit is not particularly limited, but from the viewpoint of productivity, it is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less.

[0058] When the copolymer (A1) comprises copolymer (A1-1) and copolymer (A1-2), from the viewpoint of effectively utilizing the properties of the two copolymers, the weight ratio of copolymer (A1-1) to copolymer (A1-2) (A1-1 / A1-2) is preferably 40 / 60 to 99 / 1, more preferably 60 / 40 to 97 / 3, and even more preferably 80 / 20 to 95 / 5.

[0059] The copolymer (A1) may consist solely of copolymer (A1-1), may consist solely of copolymer (A1-1) and copolymer (A1-2), or may contain poly(3-hydroxyalkanoate) copolymers that are not either copolymer (A1-1) or copolymer (A1-2). Examples of such poly(3-hydroxyalkanoate) copolymers include copolymers of 3-hydroxybutyrate units and other hydroxyalkanoate units containing 24 mol% or more of other hydroxyalkanoate units.

[0060] The total amount of copolymer (A1-1) and copolymer (A1-2) relative to the total amount of copolymer (A1) is preferably 70 to 100% by weight, more preferably 80 to 100% by weight, and even more preferably 90 to 100% by weight.

[0061] [Poly(3-hydroxybutyrate)(A2)]

[0062] In addition to the poly(3-hydroxyalkanoate) copolymer (A1) described above, the film-forming resin composition of this embodiment more preferably contains poly(3-hydroxybutyrate) (A2). Poly(3-hydroxybutyrate) (A2) exhibits higher crystallinity than the copolymer (A1) and has the property of easy curing. Therefore, by incorporating (A2), the curability after heating and melting can be further improved.

[0063] Poly(3-hydroxybutyrate) (A2) refers to a homopolymer of 3-hydroxybutyrate, or a polymer containing a small amount of hydroxyalkyl ester units other than 3-hydroxybutyrate units. Specifically, in the total monomer content of poly(3-hydroxybutyrate) (A2), the proportion of 3-hydroxybutyrate units is preferably more than 99 mol% and less than 100 mol%.

[0064] The hydroxyalkanoate units that can be included in poly(3-hydroxybutyrate) (A2) other than 3-hydroxybutyrate units are not particularly limited, as long as they can copolymerize with 3-hydroxybutyrate units. Examples include 3-hydroxyalkanoate units other than 3-hydroxybutyrate units and hydroxyalkanoate units other than 3-hydroxyalkanoate units (e.g., 4-hydroxyalkanoate units). 3-hydroxyhexanoate units are particularly preferred.

[0065] The weight-average molecular weight of poly(3-hydroxybutyrate) (A2) is not particularly limited, but from the viewpoint of film strength and curability, it is preferably 200,000 to 2,000,000, more preferably 300,000 to 1,500,000. This weight-average molecular weight can be determined by the method described above.

[0066] In the film-forming resin composition of this embodiment, from the viewpoint of improved curability due to the combination of (A2), the content of poly(3-hydroxybutyrate) (A2) in the total weight of the poly(3-hydroxyalkanoate) copolymer (A1) and poly(3-hydroxybutyrate) (A2) is preferably 1% by weight or more, more preferably 3% by weight or more, and even more preferably 5% by weight or more. From the viewpoint of film strength, the upper limit is preferably 50% by weight or less, more preferably 40% by weight or less, even more preferably 30% by weight or less, even more preferably 25% by weight or less, and particularly preferably 20% by weight or less.

[0067] The total amount of copolymer (A1) and poly(3-hydroxybutyrate) (A2) relative to the total amount of P3HA resin (A) is preferably 70 to 100% by weight, more preferably 80 to 100% by weight, and even more preferably 90 to 100% by weight.

[0068] There are no particular limitations on the method for obtaining a mixture of two or more poly(3-hydroxyalkanoate) resins. The mixture can be obtained through microbial production or through chemical synthesis. Alternatively, a mixture can be obtained by melt-blending two or more resins using an extruder, kneader, Banbury mixer, roller, etc., or by dissolving two or more resins in a solvent, mixing, and drying them.

[0069] The weight-average molecular weight of the P3HA resin (A) is not particularly limited, but from the point of view of film strength and productivity, it is preferably 200,000 to 2,000,000, more preferably 300,000 to 1,500,000, and even more preferably 400,000 to 1,000,000.

[0070] The manufacturing method of poly(3-hydroxyalkanoate) resins is not particularly limited and can be based on chemical synthesis or microbial methods. Microbial methods are preferred. Known methods can be used for microbial manufacturing. For example, *Aeromonas caviae*, a producer of P3HB3HV and P3HB3HH, and *Alcaligenes eutrophus*, a producer of P3HB4HB, are known as producing bacteria that produce copolymers of 3-hydroxybutyrate and other hydroxyalkanoates. In particular, regarding P3HB3HH, to improve the productivity of P3HB3HH, the eutrophic alkali-producing bacterium AC32 strain (Alcaligenes eutrophus AC32, FERM BP-6038) (T. Fukui, Y. Doi, J. Bateriol., 179, p4821-4830 (1997)) with genes introduced into the P3HA synthase group is more preferred. Microbial cells containing P3HB3HH can be cultured under suitable conditions. In addition to the above, recombinant microorganisms with genes introduced into various poly(3-hydroxyalkanoate) resin synthesis-related genes according to the desired poly(3-hydroxyalkanoate) resin can also be used, provided that the culture conditions, including the type of substrate, are optimized.

[0071] As the P3HA-based resin (A), an unmodified poly(3-hydroxyalkanoate) resin can be used. However, a resin in which the unmodified poly(3-hydroxyalkanoate) resin has been modified by using a raw material that can react with the resin, such as a peroxide (hereinafter referred to as "modifying raw material"), can also be used.

[0072] As the raw material for the above-mentioned modification, any compound that can react with poly(3-hydroxyalkanoate) resins is acceptable, and there are no particular limitations. From the viewpoint of operability and ease of control of the reaction with poly(3-hydroxyalkanoate) resins, organic peroxides are preferred. As the above-mentioned organic compound, known compounds may be used appropriately.

[0073] [Polylactic acid resin (B)]

[0074] Polylactic acid (PLA) resin (B) is a polyester with lactic acid as its constituent monomer. The glass transition temperature of poly(3-hydroxyalkanoate) resins is around 0°C, while that of PLA resins is typically around 60°C. Therefore, curing is carried out at temperatures below 60°C. Thus, by incorporating PLA resin (B), the curability of compositions containing poly(3-hydroxyalkanoate) resins can be improved.

[0075] Furthermore, polylactic acid (PLA) resins typically have a glass transition temperature of around 60°C, and they do not readily crystallize into an amorphous state upon rapid cooling from a molten state. Therefore, by incorporating PLA resin (B), the film softens easily even at relatively low temperatures exceeding 60°C. Consequently, the tensile properties of films containing poly(3-hydroxyalkanoate) resins can be improved by incorporating PLA resin (B). Based on this, no breakage occurs during stretching, resulting in a high-quality stretched film without stretching unevenness. Moreover, film stretching can be performed continuously and stably. Furthermore, high stretch ratios can be achieved.

[0076] The polylactic acid resin (B) is preferably a homopolymer of lactic acid, and may contain trace amounts of other monomers in addition to lactic acid.

[0077] The lactic acid constituting the polylactic acid resin (B) can be either L-form or D-form, or may contain both. In the case of the latter, the ratio of L-form to D-form is not particularly limited.

[0078] Polylactic acid resin (B) can be any of poly(L-lactic acid) resin, poly(D-lactic acid) resin, and poly(DL-lactic acid) resin. Alternatively, it can be a mixture thereof.

[0079] Other monomers that may be included in polylactic acid resins (B) include: aliphatic hydroxycarboxylic acids other than lactic acid, aliphatic polyols, aliphatic polycarboxylic acids, and polyfunctional polysaccharides.

[0080] When polylactic acid resin (B) is a copolymer of lactic acid and other monomers, from the viewpoint of crystallinity, the content of the other monomers is preferably about 0 to 3 mol% relative to the total number of monomers contained in polylactic acid resin (B), and more preferably 0 to 2 mol%.

[0081] As for the polylactic acid (PLA) resin (B), either a crystalline PLA resin or an amorphous PLA resin is acceptable. However, from the viewpoint of heat resistance, such as shrinkage during heating in post-processing steps like printing and vapor deposition, a crystalline PLA resin is preferred. Among crystalline PLA resins, those with a melting point peak having a peak temperature below 170°C in differential scanning calorimetry are particularly preferred.

[0082] From the viewpoint of improving the productivity, tensile strength, and elasticity of the membrane, the peak temperature of the melting point of the polylactic acid resin (B) (hereinafter also referred to as "melting point peak temperature" or "melting point") is preferably 165°C or lower, more preferably 160°C or lower. Further, it is preferably below 160°C, particularly preferably 155°C or lower. Additionally, from the viewpoint of improving the productivity and tensile strength of the membrane, the lower limit of the aforementioned peak temperature is preferably 120°C or higher, more preferably 130°C or higher, and even more preferably 140°C or higher.

[0083] In the DSC curve obtained by differential scanning calorimetry (DSC measurement), the above-mentioned melting point peak temperature refers to the peak temperature Tm of the crystallization melting peak. The DSC curve is obtained by accurately weighing approximately 5 mg of the target resin and heating it from 0 °C to 200 °C using a differential scanning calorimeter at a heating rate of 10 °C / min.

[0084] As for the polylactic acid resin (B) that shows the peak melting temperature as described above, there are no particular limitations, and commercially available products can be used. For example, a polylactic acid resin in which the purity of the lactic acid unit is 88% or more and 98% or less can be used.

[0085] From the viewpoint of improving the productivity and tensile strength of the membrane, it is preferable that the peak melting point temperature of the polylactic acid resin (B) is close to that of the P3HA resin (A). Specifically, the absolute value of the difference between the peak melting point temperature of the polylactic acid resin (B) and the peak melting point temperature of the P3HA resin (A) is preferably 40°C or less, more preferably 30°C or less, and even more preferably 20°C or less.

[0086] The peak melting point temperature of P3HA resin (A) was measured in the same manner as that of polylactic acid resin (B). Furthermore, in the DSC curve measured for P3HA resin (A), when multiple melting point peaks appeared, the peak temperature of the melting point peak present on the highest temperature side was set as the peak melting point temperature of P3HA resin (A).

[0087] The molecular weight of polylactic acid resin (B) is not particularly limited and can be set appropriately. The number average molecular weight is preferably 1,000 to 700,000, and more preferably 10,000 to 300,000.

[0088] There are no particular limitations on the lactic acid raw material used in the manufacture of polylactic acid resins (B). L-lactic acid, D-lactic acid, DL-lactic acid or mixtures thereof, L-lactide, D-lactide, meso-lactide or mixtures thereof, etc., can be used. Lactic acid obtained by microbial fermentation from renewable raw materials of plant origin such as starch can be suitably utilized.

[0089] As a method for manufacturing polylactic acid resin (B), known methods such as dehydration condensation polymerization and ring-opening polymerization can be used, and there are no particular limitations.

[0090] In the film-forming resin composition of this embodiment, the amount of polylactic acid resin (B) in the total amount of P3HA-based resin (A) and polylactic acid-based resin (B) is 20% by weight or more and 65% by weight or less. By incorporating 20% ​​or more of polylactic acid resin (B), even with a low content of fatty acid amide (C), which is a component that improves curability, good curability after heating and melting can be achieved. From the viewpoint of further improving curability and improving the tensile strength of the film, the amount of polylactic acid resin (B) is preferably 25% by weight or more, more preferably 30% by weight or more, and even more preferably 35% by weight or more. Alternatively, it can be 40% by weight or more, 45% by weight or more, 50% by weight or more, or 55% by weight or more.

[0091] Furthermore, by limiting the amount of polylactic acid resin (B) to 65% by weight or less, the biodegradability (particularly the biodegradability and marine decomposition of the resin composition for membrane forming and the membrane itself) can be improved. Preferably, it is 60% by weight or less, more preferably 50% by weight or less, and even more preferably 45% by weight or less.

[0092] The film-forming resin composition of this embodiment is a resin film mainly composed of P3HA-based resin (A) and polylactic acid-based resin (B). Specifically, the total content of P3HA-based resin (A) and polylactic acid-based resin (B) in the film-forming resin composition, excluding inorganic fillers, is 98.5% by weight or more. This improves the biodegradability of both the film-forming resin composition and the film, and improves the printability and / or vapor deposition properties relative to the film surface, addressing components that might reduce printability and / or vapor deposition properties.

[0093] The total content of P3HA-based resin (A) and polylactic acid-based resin (B) is preferably 99.0% by weight or more, more preferably 99.5% by weight or more, and even more preferably 99.9% by weight or more. It can also be 100% by weight. The total content of resin (A) and resin (B) mentioned here refers to the proportion of the total amount of the film-forming resin composition when the film-forming resin composition does not contain inorganic fillers, and when the film-forming resin composition contains inorganic fillers, it refers to the proportion of the total amount of the film-forming resin composition excluding inorganic fillers. The inorganic fillers mentioned here include layered clay minerals (D) described later, and inorganic fillers not corresponding to component (D) (e.g., silica-based compounds such as crystalline silica, fused silica, and amorphous silica, metal salt compounds such as calcium carbonate, magnesium carbonate, and barium sulfate).

[0094] [Fatty acid amide (C)]

[0095] The film-forming resin composition of this embodiment is a resin composition in which the amount of a fatty acid amide (C), which is known to function as a crystal nucleating agent, is reduced compared to poly(3-hydroxyalkanoate) resins. This improves the printability and / or vapor deposition properties of the film surface.

[0096] In the case of the film-forming resin composition of this embodiment, although the content of fatty acid amide (C) is low, by combining it with polylactic acid resin (B) in a specific amount, it is possible to promote curing after heating and melting, thereby shortening the time required for composite or film forming.

[0097] As fatty acid amides (C), examples include: [examples would be inserted here]. Oleamide, erucamide, stearamide, palmitamide, N-stearamide Acetic acid amides, N-stearyl erucamide, ethylene bis-stearamide, ethylene bis-oleamide, ethylene bis-erucamide, ethylene bis-laurate amide, ethylene bis-decanoate amide, p-phenylene bis-stearamide, condensates of ethylenediamine with stearic acid and sebacic acid, etc. As a fatty acid amide (C), from the viewpoint of particularly excellent curing promoting effect, [the specific type of amide] is preferred. Acetic acid amides and / or erucic acid amides. Fatty acid amides (C) can be used alone or in combination, and the ratio can be adjusted appropriately according to the purpose.

[0098] In the film-forming resin composition of this embodiment, the amount of fatty acid amide (C) is 0 parts by weight or more and less than 0.5 parts by weight relative to 100 parts by weight of P3HA-based resin (A). The lower the amount of fatty acid amide (C), the better the printability and / or vapor deposition properties become. Preferably less than 0.3 parts by weight, more preferably less than 0.2 parts by weight, and even more preferably less than 0.1 parts by weight.

[0099] In particular, from the viewpoint of further improving printability and / or vapor deposition properties, the film-forming resin composition of this embodiment preferably does not substantially contain fatty acid amide (C). "Substantially does not contain fatty acid amide (C)" means that the amount of fatty acid amide (C) is considered insufficient to function as a crystal nucleating agent for the P3HA-based resin (A), or it is zero. As such an amount of fatty acid amide (C), if specific values ​​are given, it is, for example, 0 parts by weight or more and less than 0.1 parts by weight relative to 100 parts by weight of the total amount of P3HA-based resin (A). It can be less than 0.05 parts by weight or less than 0.01 parts by weight. The most preferred amount of fatty acid amide (C) is zero.

[0100] [Layered clay minerals (D)]

[0101] The resin composition for film forming in this embodiment preferably further contains layered clay minerals (D). This further promotes curing after heating and melting, and can further shorten the time required for lamination or film forming.

[0102] Layered clay minerals are minerals whose main component is layered silicate.

[0103] There are no particular limitations on the layered clay mineral (D), and any known mineral can be used. From the viewpoint of easily achieving a solidification and improvement effect, it is preferably selected from one or more of montmorillonite, mica, talc, pyrophyllite, vermiculite, chlorite, kaolinite, and serpentine. From the viewpoint of versatility, mica, talc, and kaolinite are preferred, and talc is particularly preferred.

[0104] Examples of mica include wet-processed pulverized mica and dry-processed pulverized mica.

[0105] Examples of talc include general-purpose talc and surface-treated talc.

[0106] Examples of kaolinite include dry kaolin, calcined kaolin, and wet kaolin.

[0107] The amount of layered clay mineral (D) is not particularly limited, but from the viewpoint of improving the curing properties after heating and melting, it is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, and even more preferably 1 part by weight or more, relative to 100 parts by weight of P3HA-based resin (A). On the other hand, from the viewpoint of improving printability and / or vapor deposition properties, and / or improving the transparency of the film, the amount of layered clay mineral (D) relative to 100 parts by weight of P3HA-based resin (A) is preferably 8 parts by weight or less, more preferably 5 parts by weight or less, even more preferably 4 parts by weight or less, and particularly preferably 3 parts by weight or less.

[0108] (Crystallization nucleating agent)

[0109] The film-forming resin composition of this embodiment may include a crystallizing nucleating agent. Examples of crystallizing nucleating agents include sugar alcohols such as pentaerythritol, galactitol, and mannitol; orotic acid, aspartame, cyanuric acid, glycine, zinc phenylphosphonate, and boron nitride. Among these, sugar alcohols are preferred from the viewpoint that they are particularly effective in promoting the crystallization of P3HA-based resins (A), and pentaerythritol is especially preferred. One or more crystallizing nucleating agents may be used, and the ratio of the two agents used may be adjusted appropriately according to the purpose.

[0110] When using a crystallizing nucleating agent, there is no particular limitation on its amount. From the viewpoint of balancing the crystallization promoting effect with the improvement of printability and / or vapor deposition properties, it is preferably 0.1 to 1.5 parts by weight, more preferably 0.5 to 1.0 parts by weight, relative to 100 parts by weight of P3HA-based resin (A).

[0111] However, the molding resin composition of this embodiment may be substantially free of sugar alcohols such as pentaerythritol. In a substantially sugar alcohol-free manner, the problem of sugar alcohols seeping out of the molten resin material and contaminating the manufacturing apparatus surface (e.g., the surface of the casting roller) that the resin composition comes into contact with can be avoided, and the printability and / or vapor deposition properties of the film surface can be further improved.

[0112] Even though the resin composition for film forming in this embodiment does not substantially contain sugar alcohols, by combining a specific amount of polylactic acid resin (B), the curing after heating and melting is promoted, which can shorten the time required for composite or film forming.

[0113] Essentially, "no sugar alcohols" refers to the amount of sugar alcohols considered incapable of functioning as nucleating agents for the P3HA-based resin (A), or even zero. If specific values ​​are given for the amount of sugar alcohols, for example, amounts of 0 parts by weight or less than 0.1 parts by weight relative to 100 parts by weight of the total P3HA-based resin (A) can be given. It can be less than 0.05 parts by weight or less than 0.01 parts by weight. The most preferred amount of sugar alcohols is zero.

[0114] Such sugar alcohols can be compounds known to act as nucleating agents for the crystallization of poly(3-hydroxyalkanoate) resins. Specifically, in addition to pentaerythritol, examples include: erythritol, D-arabinitol, ribitol, xylitol, galactitol, D-mannitol, L-mannitol, D-sorbitol, inositol, squalene, maltitol, lactitol, etc. Preferably, they do not substantially contain pentaerythritol.

[0115] (Other resins)

[0116] Without impairing the effects of the invention, the film-forming resin composition of this embodiment may contain resins other than P3HA-based resin (A) and polylactic acid-based resin (B). Examples of such other resins include aliphatic polyester resins such as polybutylene adipate, polybutylene succinate, and polycaprolactone; and aliphatic aromatic polyester resins such as polybutylene adipate, polybutylene sebacic acid, and polybutylene azelaic acid. The composition may contain only one or more of these other resins.

[0117] The content of the other resins mentioned above is not particularly limited, but is preferably 1.5 parts by weight or less, more preferably 1.0 parts by weight or less, even more preferably 0.5 parts by weight or less, and particularly preferably 0.1 parts by weight or less, relative to a total of 100 parts by weight of P3HA-based resin (A) and polylactic acid-based resin (B). The lower limit of the content of the other resins is not particularly limited, and can be 0 parts by weight or more.

[0118] The film-forming resin composition of this embodiment may include additives that can be used with P3HA-based resins (A) and polylactic acid-based resins (B) to a extent that does not impair the effects of the invention. Examples of such additives include: colorants such as pigments and dyes; odor absorbers such as activated carbon and zeolite; fragrances such as vanillin and dextrin; fillers, plasticizers, oxidation inhibitors, antioxidants, weather resistance modifiers, ultraviolet absorbers, release agents, water repellents, antibacterial agents, and slip modifiers. Only one additive may be included, or two or more additives may be included. The content of these additives may be appropriately set by those skilled in the art according to their intended use.

[0119] The following is a more detailed explanation of the filler materials and plasticizers.

[0120] (Filling material)

[0121] The resin composition for film forming in this embodiment may contain a filler material. By including a filler material, a film with higher strength can be produced. The filler material can be either an inorganic filler material or an organic filler material, or a combination of both. The inorganic filler material can be any inorganic filler material that does not belong to the layered clay mineral (D) described above, such as silicates, carbonates, sulfates, phosphates, oxides, hydroxides, nitrides, carbon black, etc. Only one inorganic filler material may be used, or two or more may be used in combination.

[0122] When using filler materials other than layered clay minerals (D), their content is not particularly limited, but is preferably 1 to 100 parts by weight relative to a total of 100 parts by weight of P3HA resin (A) and polylactic acid resin (B), more preferably 3 to 80 parts by weight, even more preferably 5 to 70 parts by weight, and even more preferably 10 to 60 parts by weight.

[0123] However, from the viewpoint of improving printability and / or vapor deposition properties, the resin composition for film forming in this embodiment preferably does not contain substantially any filler material other than layered clay mineral (D). "Substantially not containing filler other than layered clay mineral (D)" means that the amount of filler other than layered clay mineral (D) is less than 1 part by weight relative to a total of 100 parts by weight of the P3HA-based resin (A) and the polylactic acid-based resin (B). It can be less than 0.5 parts by weight or less than 0.1 parts by weight.

[0124] (Plasticizer)

[0125] The film-forming resin composition of this embodiment may include a plasticizer. Examples of plasticizers include: glyceryl ester compounds, citrate compounds, sebacic acid ester compounds, adipate compounds, polyether ester compounds, benzoate compounds, phthalate compounds, isosorbide ester compounds, polycaprolactone compounds, and diester compounds. From the viewpoint of particularly excellent plasticizing effect on P3HA-based resins (A), glyceryl ester compounds, citrate compounds, sebacic acid ester compounds, and diester compounds are preferred. Examples of glyceryl ester compounds include glyceryl diacetate monolaurate. Examples of citrate compounds include acetyl tributyl citrate. Examples of sebacic acid ester compounds include dibutyl sebate. Examples of diester compounds include benzyl methyl diethylene glycol adipate. One or more plasticizers may be used, and the ratio of used plasticizers may be adjusted appropriately according to the purpose.

[0126] When using a plasticizer, the amount used is not particularly limited, but is preferably 0.1 to 1.5 parts by weight, more preferably 0.5 to 1.0 parts by weight, relative to 100 parts by weight of the total P3HA-based resin (A) and polylactic acid-based resin (B). However, from the viewpoint of improving printability and / or vapor deposition properties, the film-forming resin composition of this embodiment preferably does not contain a plasticizer substantially. "Substantially not containing a plasticizer" means that the amount of plasticizer is less than 1 part by weight relative to 100 parts by weight of the total P3HA-based resin (A) and polylactic acid-based resin (B). This can be less than 0.5 parts by weight or less than 0.1 parts by weight.

[0127] The method for manufacturing the film-forming resin composition of this embodiment is not particularly limited. It can be manufactured by conventionally mixing P3HA-based resin (A), polylactic acid-based resin (B), and other components as needed, followed by melt blending. Melt blending can be performed using a single-screw or twin-screw extruder, a Banbury mixer, a pressure kneader, a grinding roller, or other similar mixers. Through such melt blending, particles formed from the film-forming resin composition can be produced. However, the shape of the film-forming resin composition is not limited to particles.

[0128] According to this embodiment, by combining polylactic acid resin (B) in a specific amount, the manufacturing time required for the resin composition for film forming, i.e., the time required for compounding, can be shortened.

[0129] [membrane]

[0130] One aspect of this embodiment relates to a membrane. Because the membrane of this embodiment contains a specific amount of polylactic acid resin (B), it can be manufactured with good productivity.

[0131] The composition of the membrane is set within the range of the above-described composition of the resin composition for membrane molding in this embodiment, therefore detailed descriptions are omitted. However, the above-described "total amount of the resin composition for membrane molding excluding inorganic fillers" is replaced with "total amount of the membrane excluding inorganic fillers" in the context of membranes.

[0132] The membrane in this embodiment can be a membrane manufactured using the membrane forming resin composition described above, or a membrane manufactured directly by mixing and melting the components without using the composition. Alternatively, it can be a membrane manufactured by adding other components to the membrane forming resin composition described above.

[0133] The membrane can be an unstretched membrane without any stretching treatment, or a stretched membrane that has been stretched along the MD direction and / or TD direction after membrane forming. The term "membrane" as used in this application can include both unstretched and stretched membranes. From a strength point of view, a stretched membrane is preferred.

[0134] From the viewpoints of uniform film thickness, appearance, strength, and lightweight, the thickness of the film (especially the stretch film) in this embodiment is preferably 10 to 200 μm, more preferably 15 to 150 μm, and even more preferably 20 to 100 μm.

[0135] Furthermore, the membrane in this embodiment is preferably an industrially produced long-length membrane, and particularly preferably a strip membrane wound into a roll. The length of such a membrane is not particularly limited; for example, it can be 50 m or more, or 100 m or more. In this embodiment, such long-length membranes can be manufactured continuously and stably.

[0136] For example, in order to ensure the visibility of the packaged item when using the film for packaging purposes, the film of this embodiment preferably has transparency. From this viewpoint, the haze value exhibited by the film of this embodiment is preferably 70% or less, more preferably 60% or less, further preferably 50% or less, and particularly preferably 40% or less. The haze value refers to the value measured according to the methods described below in accordance with JIS K7136-1:1999 and K7316:2000.

[0137] The film of this embodiment has good printability and vapor deposition properties, therefore, a vapor-deposited layer or a printed layer can be directly formed on the surface of the film. Therefore, the film of this embodiment can be suitably used as a film for forming vapor-deposited layers or printed layers. Furthermore, the film of this embodiment can have a vapor-deposited layer or a printed layer on at least a portion of its surface. It should be noted that details of the vapor-deposited layer or printed layer will be described later.

[0138] [Membrane manufacturing methods]

[0139] Next, an example of a method for manufacturing the membrane of this embodiment will be described, but the present invention is not limited to the following description.

[0140] There are no particular limitations on the film forming method; the preferred method is to extrude the molten film material through a T-die, i.e., extrusion molding. Extrusion molding allows for the easy production of films with uniform thickness. Single-screw extruders, twin-screw extruders, etc., can be appropriately used in extrusion molding.

[0141] When the film-forming resin composition of this embodiment is fed into an extruder, it can be fed together with other components. Examples of such other components include resin additives and polylactic acid resins. However, the amount of these other components added is set in such a way that the composition after adding these other components falls within the range of the composition described above for the film-forming resin composition.

[0142] In particular, when the content of polylactic acid resin (B) in the film-forming resin composition of this embodiment is relatively low, in order to improve the productivity and tensile properties of the film during film forming, a mixed polylactic acid resin (B) can be added to the film-forming resin composition of this embodiment to increase the content of polylactic acid resin (B) in the film. In this case, it is preferable to dry-mix the film-forming resin composition and the polylactic acid resin (B) before feeding them into the extruder. However, the amount of polylactic acid resin (B) added is set such that the content of polylactic acid resin (B) in the final film falls within the range of the aforementioned content of polylactic acid resin (B) in the film-forming resin composition.

[0143] The conditions for melting the membrane raw material are simply the same as those for melting P3HA-based resin (A) and polylactic acid-based resin (B). The temperature of the molten membrane raw material can be set to, for example, around 140~210℃.

[0144] Next, the molten membrane material is extruded onto a casting roll to form a film. The molten membrane material cools and solidifies by contacting the casting roll and moving along its surface. According to this embodiment, since a specific amount of polylactic acid resin (B) is incorporated, even with a reduced amount of fatty acid amide (C), the time required for the curing of the molten resin based on the casting roll can be shortened, thereby increasing the membrane production speed.

[0145] This process can be a process of extruding molten material onto one or more casting rolls; or it can be a process of clamping the molten material extruded onto the casting roll into the contact roll by positioning the contact roll opposite the casting roll.

[0146] In addition, air knives or air chambers can be used to ensure stable contact between the molten material and the casting roll. To ensure efficient cooling of the opposite side of the contact surface with the casting roll, the casting roll can be placed in a water tank or an air chamber can be used.

[0147] To suppress the adhesion of the P3HA-based resin (A) and improve its peelability from the casting roll, the lower limit of the set temperature of the casting roll is preferably 0°C or higher, more preferably 10°C or higher, and even more preferably 15°C or higher. Furthermore, it is preferably a temperature exceeding the glass transition temperature (Tg) of the P3HA-based resin (A) by 10°C.

[0148] There is no particular upper limit to the set temperature of the casting roll, but from the viewpoint of promoting the curing of P3HA-based resin (A), it is preferably 80°C or below, and more preferably 60°C or below.

[0149] Next, while rotating the casting roller, the cooled film fed onto the roller is peeled off. This yields an unstretched film.

[0150] Next, the obtained membrane is stretched along the MD direction, thereby obtaining a uniaxially stretched membrane with high strength in the MD direction. The MD direction is also called the mechanical direction, flow direction, or longitudinal direction. The TD direction, which will be described later, is the direction perpendicular to the MD direction, and is also called the perpendicular direction or transverse direction.

[0151] The stretching process in the MD direction can be carried out continuously within a production line, starting from stripping from the casting rolls. This process is not particularly limited; for example, it can be implemented using a longitudinal stretching machine with a speed difference between the rolls conveying the film.

[0152] The stretching process in the MD direction is preferably performed while the film is being heated. There are no particular limitations on the heating method, but examples include: blowing an airflow adjusted to a given temperature onto the film; setting the rollers to a given temperature to control the film temperature; using auxiliary heating methods such as IR heaters to heat the film and control its temperature to a given level; and passing the film through an oven preheated to a given temperature. These methods can be used individually or in combination.

[0153] In the manufacturing of the film according to this embodiment, the temperature during stretching along the MD direction is preferably 35°C or higher, more preferably 45°C or higher, and even more preferably 55°C or higher. Since polylactic acid resins typically have a glass transition temperature of around 60°C, they do not easily crystallize into an amorphous state when rapidly cooled from a molten state. Therefore, even below the melting point of poly(3-hydroxyalkanoate) resins, the film of this embodiment softens easily within the above-mentioned temperature range, thereby enabling good stretching. Furthermore, the above-mentioned temperature is easily controlled and stabilized. Therefore, film stretching can be performed continuously and stably, enabling the stable manufacture of long-length stretched films.

[0154] In addition, there is no particular upper limit to the temperature when stretching along the MD direction. From the viewpoint of avoiding film breakage during stretching, it is preferable to be below 110°C, more preferably below 100°C, and even more preferably below 90°C.

[0155] The stretching ratio along the MD direction is not particularly limited, but is preferably 2 times or more. More preferably, it is 2.5 times or more, and even more preferably 3 times or more. Based on the composition of the membrane material of this embodiment, a high stretching ratio can be achieved in this way. The upper limit of the stretching ratio is not particularly limited, and can be appropriately determined, for example, it can be 8 times or less.

[0156] Next, after stretching along the MD direction, stretching is performed along the TD direction, thereby obtaining a biaxially oriented film with high strength in both the MD and TD directions. The stretching process along the TD direction can be carried out continuously within a production line, starting from the stretching process along the MD direction. This process is not particularly limited; for example, it can be carried out by using a transverse stretching machine such as a tenter frame to clamp both ends of the film in the width direction and stretching it along the TD direction.

[0157] The stretching process along the TD direction is preferably performed simultaneously with heating the film. There are no particular limitations on the heating method; the aforementioned method in the stretching process along the MD direction can be cited as an example.

[0158] The temperature during stretching along the TD direction can be the same as the temperature during stretching along the MD direction, preferably 35~110℃, more preferably 45~100℃, and even more preferably 55~90℃.

[0159] The stretching ratio along the TD direction is not particularly limited, but is preferably 2 times or more. More preferably, it is 3 times or more, and even more preferably 4 times or more. Based on the composition of the membrane material in this embodiment, a high stretching ratio can be achieved in this way. The upper limit of the stretching ratio is not particularly limited, and can be appropriately determined, for example, it can be 8 times or less.

[0160] After the stretching process along the MD direction or the stretching process along the TD direction, it is preferable to perform a heat-fixing process that heats the stretched film to a high melting point temperature for crystallization growth. This increases the crystallinity of the stretched film, thereby improving its strength and stabilizing its physical properties.

[0161] The preferred heating temperature for heat setting is 80-150°C, more preferably 90-135°C, and most preferably 100-130°C. If the heating temperature is above 80°C, the crystallinity of the stretched film increases, and the formed crystals can have a high melting point. If the heating temperature is below 150°C, breakage due to film melting can be avoided.

[0162] This heating can be performed, for example, by stretching the object along the TD direction using a transverse stretching machine such as a tenter frame, and then heating it while maintaining the stretched state. In this case, since thermal shrinkage occurs in the direction opposite to the stretching direction, relaxation is preferable to prevent breakage. Relaxation is the operation of restoring the stretch in the direction opposite to the stretching direction, and the relaxation amount is preferably adjusted appropriately between 5% and 30%.

[0163] Next, a cooling film process can be performed as appropriate. Then, preferably, a process of winding the stretch film using a take-up roller is performed.

[0164] The membrane manufacturing method of this embodiment preferably performs the process from melt extrusion to the final step while continuously conveying the membrane. This allows for the production of membranes with good productivity using a simple industrial process. The manufacturing method of this embodiment can also be performed while continuously winding the manufactured membrane using a take-up roller.

[0165] In the case of continuous membrane conveying, the conveying speed is not particularly limited. From the viewpoint of membrane productivity, it is preferable to have a conveying speed of 5 m / min or more, more preferably 15 m / min or more, in the stage before stretching begins. In addition, from the viewpoint of production stability, it is also preferable to have a conveying speed of 50 m / min or less in the stage before stretching begins.

[0166] [Layered Body]

[0167] The membrane in this embodiment can be a resin membrane composed of an independent single layer, or it can be a laminate formed by stacking at least one other layer on one or both sides of the membrane (hereinafter also referred to as the first resin layer). Such a laminate also constitutes an aspect of the present invention.

[0168] As an example of these other layers, the second resin layer can be cited.

[0169] The resin constituting the second resin layer is not particularly limited, but from the viewpoint of improving the overall biodegradability of the laminate, a poly(3-hydroxyalkanoate) resin (E) is preferred. As the poly(3-hydroxyalkanoate) resin (E), the resin described above regarding the P3HA resin (A) can be used appropriately, without particular limitation. As for components other than the poly(3-hydroxyalkanoate) resin (E), there are no particular limitations, and other resins and other components known as additives for the resin layer can be used appropriately.

[0170] The second resin layer can function as a substrate layer for the first resin layer (i.e., the film in this embodiment). This substrate layer is a key layer for ensuring the strength and other physical properties of the laminate.

[0171] There is no particular limitation on the method for forming the second resin layer; it can be any of the following: co-extrusion, dry lamination, extrusion lamination, or coating.

[0172] A third resin layer, functioning as a heat-sealing layer, can be further laminated onto the second resin layer. The resin constituting the third resin layer is not particularly limited, but from the viewpoint of improving the overall biodegradability of the laminate, a poly(3-hydroxyalkanoate) resin (F) is preferred. As the poly(3-hydroxyalkanoate) resin (F), the resins described above regarding P3HA-based resins (A) can be used appropriately, without particular limitation. Components other than the poly(3-hydroxyalkanoate) resin (F) are not particularly limited, and components known as additives for the resin layer, or other resins, can be used appropriately.

[0173] As another example of the other layers constituting the laminate, vapor-deposited layers and printed layers can be mentioned. In particular, since the printability and vapor deposition properties of the film in this embodiment are improved, vapor-deposited layers or printed layers can be directly formed on the surface of the film in this embodiment. Such vapor-deposited layers or printed layers can achieve good adhesion. Therefore, in the laminate of this embodiment, the first resin layer can function as a layer for forming vapor-deposited layers or printed layers. In addition, the laminate of this embodiment can have vapor-deposited layers or printed layers on at least a portion of the surface of the first resin layer.

[0174] Vaporized layers are typically composed of inorganic materials. Examples of such inorganic materials include metals, inorganic oxides, and carbon. Specifically, examples include aluminum, alumina, silicon oxide (e.g., silicon monoxide, silicon dioxide, silicon nitride, etc.), cerium oxide, calcium oxide, and diamond-like carbon, without particular limitation. These can be used individually or in combination. From the viewpoint of vapor deposition adhesion, the aforementioned vapor-deposited layers are preferably metal vapor-deposited films, metal oxide vapor-deposited films, or silicon oxide vapor-deposited films, and particularly preferably aluminum vapor-deposited films, alumina vapor-deposited films, or silicon oxide vapor-deposited films.

[0175] The thickness of the vapor-deposited layer is not particularly limited. From the perspectives of productivity, operability, and appearance, it can be around 1~1000nm, preferably 2~50nm, and more preferably 3~100nm.

[0176] Evaporated layers can be formed using known methods such as vacuum evaporation.

[0177] The details of the printed layer are not particularly limited, and it can be formed using known printing methods and known printing inks. Examples of printing methods include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. The printing ink can be solvent-based or water-based. Furthermore, the printed layer can be a single layer or a multi-layered layer.

[0178] In a suitable laminate, a second resin layer and a third resin layer may be provided on one side of the first resin layer, which is the film of this embodiment, and a vapor-deposited layer and / or a printed layer may be directly provided on the other side of the first resin layer.

[0179] [Applications of membranes or laminates]

[0180] The film or laminate of this embodiment can be suitably used as a packaging film, heat-sealing film, twist film, etc.

[0181] Preferred embodiments of this disclosure are set forth in the following items, but the invention is not limited to the following items.

[0182] [Project 1]

[0183] A resin composition for film forming, comprising a poly(3-hydroxyalkanoate) resin (A) and a polylactic acid resin (B),

[0184] The content of the polylactic acid resin (B) in the total amount of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 20% by weight or more and 65% by weight or less.

[0185] The content of fatty acid amide (C) is 0 parts by weight or more and less than 0.5 parts by weight relative to 100 parts by weight of the poly(3-hydroxyalkanoate) resin (A).

[0186] The total content of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 98.5% by weight or more in the total amount of the film-forming resin composition excluding inorganic fillers.

[0187] [Project 2]

[0188] The film-forming resin composition according to Project 1 does not substantially contain the fatty acid amide (C).

[0189] [Project 3]

[0190] According to the film-forming resin composition of item 1 or 2, wherein,

[0191] The poly(3-hydroxyalkanoate) resin (A) contains a poly(3-hydroxyalkanoate) copolymer (A1).

[0192] [Project 4]

[0193] According to the film forming resin composition described in Project 3, wherein...

[0194] The poly(3-hydroxyalkanoate) copolymer (A1) is a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units in which the proportion of other hydroxyalkanoate units in the total of 3-hydroxybutyrate units and other hydroxyalkanoate units is more than 1 mol% and less than 24 mol%.

[0195] [Project 5]

[0196] According to the film forming resin composition described in item 3 or 4, wherein...

[0197] The poly(3-hydroxyalkanoate) copolymer (A1) is a copolymer of 3-hydroxybutyrate units and 3-hydroxyhexanoate units.

[0198] [Project 6]

[0199] The film-forming resin composition according to any one of items 1 to 5, wherein,

[0200] The poly(3-hydroxyalkanoate) resin (A) further contains poly(3-hydroxybutyrate) (A2).

[0201] [Project 7]

[0202] The film-forming resin composition according to any one of items 1 to 6, wherein,

[0203] The polylactic acid resin (B) is a crystalline polylactic acid resin.

[0204] [Project 8]

[0205] According to the film forming resin composition described in Project 7, wherein...

[0206] The melting point of the crystalline polylactic acid resin is below 160°C.

[0207] [Project 9]

[0208] The film-forming resin composition according to any one of items 1 to 8 further contains the above-mentioned layered clay mineral (D).

[0209] [Project 10]

[0210] According to the film forming resin composition described in Project 9, wherein...

[0211] The content of the layered clay mineral (D) is 1 to 8 parts by weight relative to 100 parts by weight of the poly(3-hydroxyalkanoate) resin (A).

[0212] [Project 11]

[0213] A membrane comprising a poly(3-hydroxyalkanoate) resin (A) and a polylactic acid resin (B),

[0214] The content of the polylactic acid resin (B) in the total amount of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 20% by weight or more and 65% by weight or less.

[0215] The content of fatty acid amide (C) is 0 parts by weight or more and less than 0.5 parts by weight relative to 100 parts by weight of the poly(3-hydroxyalkanoate) resin (A).

[0216] The total content of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 98.5% by weight or more in the total amount of the film excluding inorganic fillers.

[0217] [Project 12]

[0218] According to the membrane described in Project 11, wherein,

[0219] The membrane is a stretch membrane.

[0220] [Project 13]

[0221] The membrane according to item 11 or 12, wherein,

[0222] The content of the polylactic acid resin (B) in the total amount of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 30% by weight or more.

[0223] [Project 14]

[0224] A stacked body comprising:

[0225] A first resin layer comprising, as described in any one of items 1 to 10, a film-forming resin composition, and...

[0226] The second resin layer is stacked on top of the first resin layer.

[0227] [Project 15]

[0228] According to the laminated body described in Project 14, wherein...

[0229] The second resin layer contains a poly(3-hydroxyalkanoate) resin (E).

[0230] [Project 16]

[0231] According to the laminated body described in item 14 or 15, wherein,

[0232] At least a portion of the surface of the first resin layer has a vapor-deposited layer.

[0233] [Project 17]

[0234] The laminate according to any one of items 14 to 16, wherein,

[0235] At least a portion of the surface of the first resin layer has a printed layer.

[0236] Example

[0237] The following examples and comparative examples illustrate the invention in more detail, but the invention is not limited to these examples.

[0238] The following raw materials were used in the embodiments.

[0239] (Poly(3-hydroxyalkanoate) resin (A))

[0240] As P3HA-based resins (A), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH) resins of A-1 to A-2 below and poly(3-hydroxybutyrate) of A-3 below were used. 3HB represents a repeating unit of 3-hydroxybutyrate, and 3HH represents a repeating unit of 3-hydroxyhexanoate.

[0241] A-1: P3HB3HH (Average content ratio 3HB / 3HH=94 / 6 (mol% / mol%), weight-average molecular weight is 600,000 g / mol)

[0242] It was manufactured according to the method described in Example 1 of International Publication No. 2019 / 142845.

[0243] A-2: P3HB3HH (Average content ratio 3HB / 3HH = 88.9 / 11.1 (mol% / mol%), weight-average molecular weight is 600,000 g / mol)

[0244] It was manufactured according to the method described in Example (Material A-3) of International Publication No. 2013 / 147139.

[0245] A-3: PHB: Poly(3-hydroxybutyrate) (weight-average molecular weight 350,000 g / mol)

[0246] It was manufactured according to the method described in Comparative Example 1 of International Publication No. 2004 / 041936.

[0247] (Polylactic acid resin (B))

[0248] B-1: PLA (LX175 grade, manufactured by Total Corbion PLA, peak melting point temperature is 155℃)

[0249] (Fatty acid amide (C))

[0250] C-1: Mountain Acid amide (manufactured by Nippon Seika Co., Ltd.: BNT-22H)

[0251] (Layered clay minerals (D))

[0252] D-1: Talc (Made by Talc Japan: SG-200N15)

[0253] (Crystallization nucleating agent)

[0254] E-1: Pentaerythritol (manufactured by Mitsubishi Chemical Corporation, Neutizer-P) (abbreviated as PETL)

[0255] The following evaluation was performed in each embodiment and comparative example.

[0256] [Particle Formability]

[0257] For the filament extruded from the granulation die during resin granulation, the curing time was evaluated by measuring the time it took for the filament to lose its elasticity upon touch in a 45°C water bath. The filament extrusion (drawing) speed was 10 m / min, and the water bath length was 2 m. If the filament was not cured after 2 m of extrusion from the die, it was repeatedly folded back until it cured. If it was still not cured even after folding back 20 m, it was evaluated as uncured and therefore unsuitable for granulation.

[0258] [Membrane Formability]

[0259] The traction speed during film formation using a T-die was measured, and film formability was evaluated according to the following evaluation criteria. It should be noted that the traction speed is the maximum speed at which the film can be conveyed from the casting roll to the next roll without adhering to the casting roll, and serves as an indicator of sufficient curing on the casting roll. If the traction speed exceeds the maximum speed, the film's adhesiveness causes the peeling point to shift along the casting roll's rotation direction, resulting in a state of simultaneous peeling and conveying.

[0260] <Evaluation Criteria>

[0261] ○: Traction speed of 15m / min or higher

[0262] △: Traction speed is above 5m / min but below 15m / min

[0263] ×: Traction speed is below 5m / min

[0264] [Membrane tensile properties]

[0265] Using resin particles, a film was made using a T-die, and continuously stretched three times along the MD direction (the flow direction of the film made using the T-die) in a temperature range of 60℃~70℃ using a roller stretching machine. The stretchable area was evaluated according to the following evaluation criteria.

[0266] In addition, for the membrane stretched along the MD direction, the two ends in the MD direction were fixed, and it was stretched 5 times along the TD direction (the direction perpendicular to the MD direction) within a temperature range of 70℃~80℃. The stretchable area was evaluated according to the following evaluation criteria.

[0267] <Evaluation Criteria>

[0268] ○: A membrane can be obtained without breaking during stretching, and no uneven stretching (such as uneven membrane thickness) can be observed by visual inspection.

[0269] △: A membrane can be obtained without breaking during stretching. When the membrane is obtained by visual inspection, some uneven stretching can be observed (uneven stretching of membrane thickness, etc.).

[0270] ×: The membrane does not break during stretching, or uneven stretching (such as uneven membrane thickness) is observed on the entire surface of the membrane when viewed with the naked eye.

[0271] [Membrane thickness]

[0272] Ten locations were selected every 10 cm along the TD direction of the membrane, and the thickness was measured using vernier calipers. The arithmetic mean of the thickness at the ten locations was calculated and used as the membrane thickness.

[0273] [Membrane haze value]

[0274] The haze value of a 30 μm thick film was determined using a Suga HZ-V3 haze meter according to the methods described in JIS K7136-1:1999 and K7316:2000.

[0275] [Printability]

[0276] The ink was spread on the film surface manufactured in each embodiment and comparative example using a water-based black pen to confirm whether the film surface repelled the ink.

[0277] ○: The membrane surface does not repel ink.

[0278] ×: Ink repellent on the membrane surface

[0279] [Vapor Deposition Properties]

[0280] On the film surface manufactured in each embodiment and comparative example, a vapor-deposited layer (film thickness 100 nm) containing aluminum as an inorganic material was formed.

[0281] The vapor deposition layer was formed on a 30mm square film using a film forming apparatus (UHSP-T2040H, manufactured by Shimadzu Corporation) under an argon atmosphere.

[0282] For the obtained film with vapor-deposited layer, the cross-cutting method (JIS-K5600-6) was performed, and the adhesion of the vapor-deposited layer was evaluated based on the ratio (%) of the area of ​​the vapor-deposited layer after peeling to the area of ​​the evaluation object surface.

[0283] <Evaluation Criteria>

[0284] ○: The area of ​​vapor-deposited layer peeling off is less than 25%.

[0285] △: The area of ​​the vapor-deposited layer peeled off is more than 25% and less than 75%.

[0286] ×: More than 75% of the vapor-deposited layer has peeled off the surface.

[0287] (Manufacturing of resin particles)

[0288] (Example 1)

[0289] A dry blend of poly(3-hydroxyalkanoate) resin A-1 (48 wt% relative to the total weight of P3HA and PLA), A-2 (4 wt%), A-3 (8 wt%), polylactic acid B-1 (40 wt%), and layered clay mineral D-1 (2 parts by weight relative to 100 parts by weight of the poly(3-hydroxyalkanoate) resin) was prepared. The resulting resin material was fed into the barrel of a φ26mm co-rotating twin-screw extruder with the barrel and die temperatures set at 150°C. The mixture was melt-blended and extruded through a die into a filament. The filament was then cured by passing it through a water bath filled with 45°C hot water and cut into granules using a granulator to obtain resin particles P-1. The particle formability was then evaluated. The evaluation results are shown in Table 1.

[0290] (Examples 2-9)

[0291] The formulation was modified as shown in Table 1, except that resin particles P-2 to P-9 were manufactured in the same manner as in Example 1. The particle formability was then evaluated. The evaluation results are shown in Table 1.

[0292] (Comparative Examples 1-4)

[0293] The formulation was modified as shown in Table 1, except that resin particles P-10 to P-13 were manufactured in the same manner as in Example 1. The particle formability was then evaluated. The evaluation results are shown in Table 1.

[0294]

[0295] As shown in Table 1, resin particles were formed in Examples 1-9 and Comparative Examples 3-4. On the other hand, in Comparative Examples 1 and 2, polylactic acid was not incorporated, and the filament did not cure under the above-mentioned test conditions, thus resin particles could not be formed.

[0296] (Manufacturing of biaxially oriented film)

[0297] (Example 10)

[0298] The resin granules P-1 were fed into a single-screw extruder with the barrel and die set to a temperature of 160°C. The extruded material was then extruded into a film through a T-die. After cooling the formed film using a casting roller at a temperature of 40°C, it was drawn by a traction roller and continuously stretched to 3 times its original length along the MD direction at 60-70°C using a roller longitudinal stretching machine. Then, it was continuously stretched along the transverse (TD) direction using a clamp-type tenter frame at a stretching temperature of 70-80°C, achieving a stretch ratio of 5 times. The biaxially stretched film was cooled to 50°C and the wide end was trimmed, resulting in a biaxially stretched film with a width of 1200 mm and a thickness of 30 μm. It should be noted that the above process was carried out continuously.

[0299] The films were observed after stretching in the MD and TD directions, and their stretchability was evaluated. Furthermore, the thickness, haze value, printability, and vapor deposition properties of the obtained stretched films were evaluated. The evaluation results are shown in Table 2.

[0300] (Examples 11-20)

[0301] The resin particles used were modified as shown in Table 2. Otherwise, the film was manufactured in the same manner as in Example 10, and the tensile properties of the film were evaluated. The thickness, haze value, printability, and vapor deposition properties of the resulting stretched film were also evaluated. The evaluation results are shown in Table 2.

[0302] It should be noted that in Example 11, during membrane manufacturing, the resin particles P-1 were dry-blended with polylactic acid B-1 and then fed into the extruder, so that the proportion of polylactic acid B-1 in the membrane reached 60% by weight (relative to the total weight of P3HA and polylactic acid).

[0303] In Examples 13 and 14, the resin particles P-3 were dry-blended with polylactic acid B-1 and then fed into an extruder, so that the proportion of polylactic acid B-1 in the film reached 30% or 40% by weight.

[0304] (Comparative Examples 5-6)

[0305] The resin particles used were modified as shown in Table 2. Otherwise, the film was manufactured in the same manner as in Example 10, and the stretchability of the film was evaluated. The thickness, haze value, printability, and vapor deposition properties of the resulting stretched film were evaluated. The evaluation results are shown in Table 2.

[0306]

[0307] As shown in Table 2, in Examples 10-20, the printability and vapor deposition properties of the obtained films were evaluated as good. On the other hand, in Comparative Example 5, the amount of fatty acid amide (C) was high, resulting in insufficient printability and vapor deposition properties. In addition, in Comparative Example 6, the total content of P3HA-based resin (A) and polylactic acid-based resin (B) in the composition other than the inorganic filler was low, resulting in insufficient printability and vapor deposition properties.

Claims

1. A resin composition for film forming, comprising a poly(3-hydroxyalkanoate) resin (A) and a polylactic acid resin (B), The content of the polylactic acid resin (B) in the total amount of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 20% by weight or more and 65% by weight or less. The content of fatty acid amide (C) is 0 parts by weight or more and less than 0.5 parts by weight relative to 100 parts by weight of the poly(3-hydroxyalkanoate) resin (A). The total content of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 98.5% by weight or more in the total amount of the film-forming resin composition excluding inorganic fillers.

2. The resin composition for film forming according to claim 1, substantially does not contain the fatty acid amide (C).

3. The resin composition for film forming according to claim 1, wherein, The poly(3-hydroxyalkanoate) resin (A) contains a poly(3-hydroxyalkanoate) copolymer (A1).

4. The resin composition for film forming according to claim 3, wherein, The poly(3-hydroxyalkanoate) copolymer (A1) is a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units in which the proportion of other hydroxyalkanoate units in the total of 3-hydroxybutyrate units and other hydroxyalkanoate units is more than 1 mol% and less than 24 mol%.

5. The resin composition for film forming according to claim 3, wherein, The poly(3-hydroxyalkanoate) copolymer (A1) is a copolymer of 3-hydroxybutyrate units and 3-hydroxyhexanoate units.

6. The resin composition for film forming according to claim 3, wherein, The poly(3-hydroxyalkanoate) resin (A) further contains poly(3-hydroxybutyrate) (A2).

7. The resin composition for film forming according to claim 1, wherein, The polylactic acid resin (B) is a crystalline polylactic acid resin.

8. The resin composition for film forming according to claim 7, wherein, The melting point of the crystalline polylactic acid resin is below 160°C.

9. The resin composition for film forming according to claim 1, further comprising layered clay minerals (D).

10. The resin composition for film forming according to claim 9, wherein, The content of the layered clay mineral (D) is 1 to 8 parts by weight relative to 100 parts by weight of the poly(3-hydroxyalkanoate) resin (A).

11. A membrane comprising a poly(3-hydroxyalkanoate) resin (A) and a polylactic acid resin (B), The content of the polylactic acid resin (B) in the total amount of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 20% by weight or more and 65% by weight or less. The content of fatty acid amide (C) is 0 parts by weight or more and less than 0.5 parts by weight relative to 100 parts by weight of the poly(3-hydroxyalkanoate) resin (A). The total content of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 98.5% by weight or more in the total amount of the film excluding inorganic fillers.

12. The membrane according to claim 11, wherein, The membrane is a stretch membrane.

13. The membrane according to claim 11, wherein, The content of the polylactic acid resin (B) in the total amount of the poly(3-hydroxyalkanoate) resin (A) and the polylactic acid resin (B) is 30% by weight or more.

14. A laminate comprising: A first resin layer, which is the film as described in claim 11; and The second resin layer is stacked on top of the first resin layer.

15. The laminate according to claim 14, wherein, The second resin layer contains a poly(3-hydroxyalkanoate) resin (E).

16. The laminate according to claim 14, wherein, At least a portion of the surface of the first resin layer has a vapor-deposited layer.

17. The laminate according to claim 14, wherein, At least a portion of the surface of the first resin layer has a printed layer.

Images