JP2016008269A - Polylactic acid-based resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polylactic acid-based resin film which has excellent flexibility and processability such as drawing, and can provide, after processing, a porous film that exhibits good moisture permeability.SOLUTION: The polylactic acid-based resin film is a film comprising a polylactic acid-based resin (A). In a spectrum obtained by DSC measurement of the film, there is an endothermic peak having a peak top in a temperature range of 20°C or more and 60°C or less. Also, a heat quantity of the endothermic peak is 1 J/g or more and 20 J/g or less.

Description

  The present invention relates to a polylactic acid-based resin film that is excellent in flexibility and processability such as stretching, and can obtain a porous film that exhibits good moisture permeability after processing.

  In recent years, with increasing environmental awareness, attention has been focused on soil pollution problems caused by the disposal of plastic products and global warming problems caused by increased carbon dioxide caused by incineration. Various biodegradable resins have been studied as countermeasures against the former, and resins made from biomass (plant-derived raw materials) that do not give a new carbon dioxide load to the atmosphere even when incinerated are being studied extensively as countermeasures against the latter. Has been developed. For example, polylactic acid has attracted attention as a resin that satisfies both measures and is relatively advantageous in terms of cost. However, when polylactic acid is applied to flexible film applications in which polyolefin such as polyethylene is used as a representative material, it lacks flexibility and impact resistance. Attempts have been made.

  On the other hand, in the field of porous films, a porous film obtained by stretching a sheet containing a polylactic acid resin, a thermoplastic resin other than the polylactic acid resin, and a filler has been proposed (see Patent Document 1). . In addition, polylactic acid resin, thermoplastic resin other than polylactic acid resin, and a film containing a surface-treated filler, polylactic acid resin excellent in workability such as stretching and embossing to exhibit moisture permeability A film has been proposed (see Patent Document 2). Furthermore, a porous sheet obtained by melting a resin composition containing an aliphatic polyester resin, a filler, and a plasticizer, forming the sheet into a sheet, and then stretching has been proposed (see Patent Document 3).

WO2012 / 023465 pamphlet WO2012 / 114810 pamphlet JP 2007-112867 A

  However, in the proposals described in Patent Documents 1 and 3, a polylactic acid resin film having a certain flexibility and bleed-out resistance was obtained, but its workability was not sufficient. Moreover, in the proposal of the above-mentioned patent document 2, although the polylactic acid-type resin film which can obtain the porous film which has fixed moisture permeability by processes, such as extending | stretching and embossing, was obtained, the softness | flexibility and processing The properties and moisture permeability after processing were still not sufficient.

  That is, the polylactic acid-based resin films having excellent flexibility have been studied so far, but their processability is not sufficient, and in particular, a porous film that is flexible and exhibits good moisture permeability by processing such as stretching. The invention of a polylactic acid-based resin film that can be obtained has not yet been achieved.

  Therefore, in view of the background of the above-described conventional technology, an object of the present invention is to provide a polylactic acid-based resin film from which a porous film that is excellent in flexibility and workability such as stretching and that exhibits good moisture permeability after processing is obtained. There is to do.

  As a result of intensive studies to solve the above problems, the present inventors have found that these problems can be solved by the following means, and have reached the present invention.

  The polylactic acid resin film of the present invention is a film containing a polylactic acid resin (A), and has an endothermic peak having a peak top in a temperature range of 20 ° C. or more and 60 ° C. or less in a spectrum obtained by DSC measurement of the film. And a heat quantity of the endothermic peak is 1 J / g or more and 20 J / g or less.

  According to a preferred embodiment of the polylactic acid-based resin film of the present invention, the polylactic acid-based resin film further contains an organic component (B), and is 40 ° C. in the spectrum of the reversible component obtained by temperature-modulated DSC measurement of the film. It has a first glass transition temperature (Tg (1)) in a temperature range of 70 ° C. or lower and a temperature range of “Tg (1) -80” ° C. or higher and “Tg (1) -20” ° C. or lower. The second glass transition temperature (referred to as Tg (2)), the specific heat difference before and after the second glass transition (referred to as ΔCp2) and the specific heat difference before and after the first glass transition (referred to as ΔCp1). ) Ratio ΔCp2 / ΔCp1 is not less than 0.01 and not more than 1.

  According to the preferable aspect of the polylactic acid-type resin film of this invention, in the spectrum of the reversible component obtained by the temperature modulation | alteration DSC measurement of the said film, "Tg (2) -100" degree C or more "Tg (2) -10" It has a third glass transition temperature (referred to as Tg (3)) in a temperature range of not higher than ° C.

  According to the preferable aspect of the polylactic acid-type resin film of this invention, said Tg (3) is -80 degreeC or more and -10 degrees C or less.

  According to the preferable aspect of the polylactic acid-type resin film of this invention, said Tg (1) is a glass transition temperature originating in a polylactic acid-type resin (A), and Tg (3) originates in an organic component (B). It is the glass transition temperature.

According to a preferred embodiment of the polylactic acid-based resin film of the present invention, in the spectrum of a reversible component obtained by temperature-modulated DSC measurement of a film containing a plasticizer (BP) as the organic component (B), the following i) Or ii) any one of the requirements.
i) The plasticizer (BP) does not have an endothermic peak of melting.
ii) The polylactic acid resin (A) and the plasticizer (BP) have an endothermic peak of melting, and the heat of fusion at the endothermic peak of melting of the plasticizer (BP) (referred to as ΔHmBP) and the polylactic acid resin (A) ) The ratio ΔHmBP / ΔHmA of the heat of fusion (referred to as ΔHmA) at the endothermic peak of melting) is 0.1 or less.

  According to a preferred aspect of the polylactic acid-based resin film of the present invention, the polylactic acid-based resin film further includes a filler (C), and the filler (C) in 100% by mass of all the components of the film. Content is 20 mass% or more and 70 mass% or less.

According to a preferred embodiment of the polylactic acid-based resin film of the present invention, the organic component (B) includes at least one selected from the following group.
[Group]: Block copolymer having polyether segment and polylactic acid segment, polyester resin obtained from aliphatic diol and aliphatic dicarboxylic acid, aliphatic diol, aliphatic dicarboxylic acid and aliphatic hydroxycarboxylic acid And a group of polyester resins obtained from aliphatic diols, aliphatic dicarboxylic acids and aromatic dicarboxylic acids.

The polylactic acid-based resin film of the present invention is preferably used for applications for producing a porous film, and using this polylactic acid-based resin film, the moisture permeability is preferably 500 g / (m ² · day) or more porous films can be produced.

  According to the present invention, it is possible to obtain a polylactic acid-based resin film that is excellent in flexibility and processability such as stretching, and that provides a porous film that exhibits good moisture permeability after processing. In particular, a polylactic acid-based resin film excellent in both flexibility and workability and further excellent to a certain extent that the moisture permeability after processing is substantially applicable to uses described later is obtained for the first time by the present invention. The polylactic acid-based resin film of the present invention is preferably used as a processing film for obtaining a porous film that exhibits good moisture permeability, and the obtained porous film mainly includes flexibility, bleed-out resistance and Bed sheets, pillow covers, medical materials and hygiene materials such as back sheets for absorbent articles such as sanitary napkins and paper diapers, clothing materials such as rainy clothes and gloves, garbage bags and compost bags, Or it can use preferably for packaging materials, such as a bag for foodstuffs, such as vegetables and fruits, and a bag of various industrial products.

  As a result of intensive studies on the above-mentioned problems, that is, a polylactic acid-based resin film from which a porous film that exhibits excellent workability such as flexibility and stretching, and exhibits good moisture permeability after processing is obtained. This is the first successful solution to the above problem.

  That is, the polylactic acid resin film of the present invention is a film containing the polylactic acid resin (A), and has a peak top in a temperature range of 20 ° C. or more and 60 ° C. or less in a spectrum obtained by DSC measurement of the film. A polylactic acid resin film having an endothermic peak and having an endothermic peak having a heat quantity of 1 J / g or more and 20 J / g or less.

  Hereinafter, the polylactic acid resin film of the present invention will be described in detail.

(Polylactic acid resin (A))
It is important that the polylactic acid resin film of the present invention contains a polylactic acid resin (A). The polylactic acid-based resin is a polymer mainly composed of an L-lactic acid unit and / or a D-lactic acid unit. Here, the main component means that the mass ratio of the lactic acid unit is the maximum in 100% by mass of the polymer. The mass ratio of the lactic acid unit is preferably 70% by mass to 100% by mass of the lactic acid unit in 100% by mass of the polymer.

  Poly L-lactic acid and poly D-lactic acid are preferably used as the polylactic acid resin. The poly L-lactic acid referred to in the present invention refers to those having a content ratio of L-lactic acid units exceeding 50 mol% and not more than 100 mol% in 100 mol% of all lactic acid units in the polylactic acid polymer. On the other hand, the poly D-lactic acid as used in the present invention refers to those having a D-lactic acid unit content of more than 50 mol% and not more than 100 mol% in 100 mol% of all lactic acid units in the polylactic acid polymer.

  In poly L-lactic acid, the crystallinity of the resin itself varies depending on the content ratio of the D-lactic acid unit. That is, as the content ratio of the D-lactic acid unit in the poly L-lactic acid increases, the crystallinity of the poly L-lactic acid decreases and approaches the amorphous state, and conversely, the content of the D-lactic acid unit in the poly L-lactic acid. As the proportion decreases, the crystallinity of poly-L-lactic acid increases. Similarly, in poly D-lactic acid, the crystallinity of the resin itself changes depending on the content ratio of the L-lactic acid unit. That is, as the content ratio of the L-lactic acid unit in the poly-D-lactic acid increases, the crystallinity of the poly-D-lactic acid decreases and approaches the amorphous state, and conversely, the content of the L-lactic acid unit in the poly-D-lactic acid. As the proportion decreases, the crystallinity of poly-D-lactic acid increases.

  The content ratio of the L-lactic acid unit in the poly L-lactic acid used in the present invention or the content ratio of the D-lactic acid unit in the poly D-lactic acid used in the present invention is from the viewpoint of maintaining the mechanical strength of the film. In 100 mol% of all lactic acid units, 80-100 mol% is preferable, More preferably, it is 85-100 mol%.

  The crystalline polylactic acid resin referred to in the present invention is a temperature of 0 ° C. to 300 ° C. at a temperature rising rate of 20 ° C./min after leaving this polylactic acid resin for 1 hour under heating at a temperature of 100 ° C. When measured with a differential scanning calorimeter (DSC), it refers to a polylactic acid resin in which the heat of crystal melting derived from the polylactic acid component is observed.

  On the other hand, the amorphous polylactic acid resin referred to in the present invention refers to a polylactic acid resin that does not exhibit a clear melting point when measured in the same manner as described above.

  From the viewpoint of improving heat resistance and blocking resistance, the crystalline polylactic acid resin used in the polylactic acid resin film of the present invention is a content ratio of L-lactic acid units in poly L-lactic acid, or poly D-lactic acid. The content ratio of the D-lactic acid unit is preferably 96 to 100 mol%, more preferably 98 to 100 mol% in 100 mol% of all lactic acid units.

  The polylactic acid resin (A) used in the present invention is preferably a mixture of a crystalline polylactic acid resin and an amorphous polylactic acid resin. When the polylactic acid resin film of the present invention contains a crystalline polylactic acid resin as the polylactic acid resin (A), the heat resistance and blocking resistance of the film are improved. On the other hand, when the polylactic acid-based resin film of the present invention contains an amorphous polylactic acid-based resin as the polylactic acid-based resin (A), it is suitable for improving the flexibility and bleed-out resistance of the film. This has an effect of providing an amorphous part in which the plasticizer can be dispersed. And the polylactic acid-type resin (A) which the polylactic acid-type resin film of this invention contains is made into the mixture of crystalline polylactic acid-type resin and amorphous polylactic acid-type resin, The polylactic acid-type resin film of this invention In contrast, the advantages of both crystalline and amorphous polylactic acid resins can be achieved.

  When the total of the crystalline polylactic acid resin and the amorphous polylactic acid resin in the polylactic acid resin film of the present invention is 100% by mass, the mass ratio of the crystalline polylactic acid resin is 5 to 60% by mass. It is preferably 10 to 50% by mass, more preferably 20 to 40% by mass. When the mass ratio of the crystalline polylactic acid resin is less than 5 mass%, the heat resistance and blocking resistance of the polylactic acid resin film may be inferior, and the mass ratio of the crystalline polylactic acid resin may be 60 mass%. When it exceeds, the softness | flexibility and bleed-out resistance as a polylactic acid-type resin film may become inadequate.

  The polylactic acid resin (A) used in the present invention can copolymerize other monomer units other than lactic acid. Other monomers include glycol compounds such as ethylene glycol, propylene glycol, butanediol and polyethylene glycol, dicarboxylic acids such as oxalic acid, adipic acid and terephthalic acid, hydroxycarboxylic acids such as glycolic acid and hydroxybutyric acid, and caprolactone And other lactones.

  The copolymerization amount of the other monomer units is preferably 0 to 30 mol%, more preferably 0 to 30 mol%, based on 100 mol% of the whole monomer units in the polymer of the polylactic acid resin. 10 mol%. Among the monomer units described above, it is preferable to select a biodegradable component according to the application, and specifically, an aliphatic monomer unit is preferable.

  The mass average molecular weight of the polylactic acid resin (A) used in the present invention is preferably 50,000 to 400,000, more preferably 70,000 in order to satisfy practical mechanical properties, water resistance and decomposability. It is -300,000, More preferably, it is 100,000-250,000, Most preferably, it is 150,000-250,000. The mass average molecular weight as used herein refers to a molecular weight calculated by a polystyrene conversion method using gel permeation chromatography (GPC) with a chloroform solvent.

  As a method for producing the polylactic acid-based resin, a known polymerization method can be used, and examples thereof include a direct polymerization method from lactic acid and a ring-opening polymerization method via lactide.

  In the polylactic acid resin film of the present invention, 100% by mass of all components of the polylactic acid resin film from the viewpoint of heat resistance, flexibility, bleed-out resistance and moisture permeability after processing such as stretching of the polylactic acid resin film. It is preferable that content of the polylactic acid-type resin (A) which occupies in it is 5-90 mass%, More preferably, it is 10-60 mass%, More preferably, it is 12-30 mass%.

(Organic component (B))
In a preferred embodiment, the polylactic acid resin film of the present invention contains an organic component (B). By including the organic component (B), the flexibility of the polylactic acid-based resin film is improved, and the possibility of obtaining a porous film having good moisture permeability after processing such as stretching is increased.

The organic component (B) includes all organic components from low molecular weight organic substances to high molecular weight resins. However, in the present invention, the polylactic acid resin is not included in the organic component (B), and the polylactic acid resin (A ). Since the organic component (B) is part of the purpose of adding flexibility and stretchability of the polylactic acid resin film, its glass transition temperature may be lower than that of the polylactic acid resin (A). Specifically, specifically, the glass transition temperature is preferably 20 ° C. or more lower than that of the polylactic acid resin (A). In the present invention, an embodiment having no glass transition temperature is also included. The organic component (B) is preferably a thermoplastic resin (other than polylactic acid resin) and / or a plasticizer (BP).
Examples of thermoplastic resins include, for example, aromatic polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and aliphatic polyester resins such as polyglycolic acid, poly (3-hydroxybutyrate), polycaprolactone, and polybutylene succinate. Resins, aliphatic aromatic polyester resins such as poly (butylene adipate terephthalate), polymers containing polysaccharides and starch, acrylic resins such as polymethyl methacrylate, polyolefin resins such as polyethylene and polypropylene, polyamide resins, polycarbonate Resin, polystyrene resin, polyether resin, polyesteramide resin, polyetherester resin, polyvinyl chloride resin, polyvinyl alcohol resin, and components thereof Copolymers to, or thermoplastic resin such as mixtures thereof.

  When a thermoplastic resin is used as the organic component (B) in the present invention, the thermoplastic resin is preferably a biodegradable resin in order to maintain the biodegradability of the entire polylactic acid resin film.

(Biodegradable resin)
The biodegradable resin in the present invention is a thermoplastic resin (other than polylactic acid resin) having biodegradability. In the present invention, “having biodegradability” means that the biodegradable resin in the film is JIS K6955 (2000), JIS K6951 (2000), JIS K6953-1 (2011), JIS K6953-2 (2010), It means that it has a degree of biodegradation of 60% or more within one year when tested in any of JIS K6955 (2006).

  As the biodegradable resin in the present invention, aliphatic polyester resins, aliphatic aromatic polyester resins, polysaccharides, polyvinyl alcohol resins and the like can be used.

  Examples of the aliphatic polyester resin include fats such as polyester resins obtained from aliphatic hydroxycarboxylic acids such as polyglycolic acid resins, polyhydroxybutyrate resins, polycaprolactone resins, and polybutylene succinate resins. A polyester resin obtained from an aliphatic diol and an aliphatic dicarboxylic acid, or a copolymer thereof can be used.

  Specific examples of the polyhydroxybutyrate-based resin include poly (3-hydroxybutyrate), poly (3-hydroxybutyrate-3hydroxyhexanoate), and poly (3-hydroxybutyrate-3 And the like. Specific examples of the polybutylene succinate resin include polybutylene succinate and poly (butylene succinate adipate). Further, a polyester resin obtained from an aliphatic hydroxycarboxylic acid and a copolymer of a polyester resin obtained from an aliphatic diol and an aliphatic dicarboxylic acid, that is, an aliphatic diol, an aliphatic dicarboxylic acid, and an aliphatic hydroxycarboxylic acid Examples of the polyester resin obtained from the above include poly (butylene succinate / lactide).

  Specific examples of the aliphatic aromatic polyester resin include aliphatic groups such as poly (ethylene succinate / terephthalate), poly (butylene succinate / terephthalate), poly (butylene adipate / terephthalate), and copolymers thereof. Examples thereof include polyester resins obtained from diols, aliphatic dicarboxylic acids, and aromatic dicarboxylic acids.

  Specific examples of polysaccharides include starch and derivatives thereof, cellulose and derivatives thereof, hemicelluloses and derivatives thereof such as glucomannan, chitin / chitosan and derivatives thereof, and the like. In addition, as a resin containing starch, a biodegradable resin “Matter-bi” (registered trademark) manufactured by Novamont, Inc. can be used.

  As the biodegradable resin, the above may be used alone, or two or more of the above may be blended. Alternatively, two or more types of the above copolymers may be used.

(Plasticizer (BP))
The plasticizer (BP) used in the present invention is a substance having a glass transition temperature lower than that of the polylactic acid resin (A) or having no glass transition temperature. It is an organic component that can lower the overall glass transition temperature compared to that of the polylactic acid resin (A) alone by mixing. Specifically, a meshing type in which L / D is 30 or more at a temperature of about 30 ° C., which is higher of the melting points of both, for example, 50% by mass of polylactic acid resin (A) and 50% by mass of plasticizer (BP). In the spectrum obtained by DSC measurement of the resin obtained by melt kneading with the same direction twin screw extruder, the glass transition temperature is intermediate between that of the polylactic acid resin (A) alone and that of the plasticizer (BP) alone. Observed at a temperature of ± 20 ° C.

  When the plasticizer (BP) does not show a glass transition temperature, the glass transition temperature of the resin obtained in the same manner is observed at a temperature lower by 30 ° C. or more than the polylactic acid resin (A) alone. The newly appearing glass transition temperature is derived from a compatible component of the polylactic acid resin (A) and the plasticizer (BP). Here, the glass transition temperature of the polylactic acid resin (A) alone and / or the glass transition temperature of the plasticizer (BP) alone may be observed. The specific heat difference between before and after the glass transition of the glass transition and / or plasticizer (BP) is before and after the glass transition derived from the compatible component of the polylactic acid resin (A) and the plasticizer (BP) present between the two. Generally, it is smaller than the specific heat difference at.

  Examples of the plasticizer (BP) include phthalate ester plasticizers such as diethyl phthalate and dioctyl phthalate, di-1-butyl adipate, di-n-butyl sebacate, and di-2-ethylhexyl azelate. Aliphatic dibasic acid plasticizers such as diphenyl-2-ethylhexyl phosphate and diphenyloctyl phosphate plasticizers such as tri-2-ethylhexyl acetyl citrate and tributyl acetyl citrate Hydroxypolycarboxylic acid ester plasticizers, fatty acid ester plasticizers such as methyl acetylricinoleate and amyl stearate, polyhydric alcohol ester plasticizers such as glycerin triacetate and triethylene glycol dicaprylate, epoxidation Soybean oil and epoxidized linseed oil fatty acid Epoxy plasticizers such as Chiruesuteru, plasticizers polyester such as polypropylene glycol sebacic acid esters, and polyalkylene ether, and a plasticizer, such as polyether ester-based and acrylate-based. Moreover, it is also possible to use a mixture of two or more of these plasticizers.

  From the viewpoint of maintaining the biodegradability of the entire polylactic acid resin film, the plasticizer (BP) preferably has biodegradability. Furthermore, from the viewpoint of the bleed-out resistance of the plasticizer (BP) and the blocking resistance of the film, the plasticizer used in the present invention is solid at room temperature (20 ° C. ± 15 ° C.), that is, has a melting point. It is preferable to exceed 35 ° C. The melting point of the plasticizer (BP) is preferably 150 ° C. or less in order to match the melt processing temperature with the polylactic acid resin (A).

  From the same viewpoint, the plasticizer (BP) is more preferably a block copolymer having a polyether segment and a polylactic acid segment. Here, the component which acts as a plasticizer of the polylactic acid resin (A) is a polyether segment. These block copolymers (hereinafter, a block copolymer having a polyether segment and a polylactic acid segment may be referred to as a “block copolymer plasticizer”) will be described below.

  The mass proportion of the polylactic acid-based segment of the block copolymer plasticizer is 50% by mass or less in 100% by mass of the entire block copolymer plasticizer from the viewpoint that desired flexibility can be imparted with a smaller amount of addition. It is preferable that it is 5 mass% or more from a viewpoint of bleed-out suppression.

  The number average molecular weight of the polylactic acid segment in one molecule of the block copolymer plasticizer is preferably 1,200 to 10,000. When the block copolymer plasticizer has a polylactic acid segment of 1,200 or more, sufficient affinity is produced between the block copolymer plasticizer and the polylactic acid resin (A). A part of the lactic acid-based segment is taken into the crystal formed from the polylactic acid-based resin (A) and forms a so-called eutectic, thereby exerting a great effect on the bleed-out suppression of the block copolymer plasticizer. As a result, the blocking resistance of the film is also excellent. Moreover, the softness | flexibility provision to a film can be performed more efficiently as the polylactic acid-type segment which a block copolymer plasticizer has is 10,000 or less. The number average molecular weight of the polylactic acid-based segment in the block copolymer plasticizer is more preferably 1,500 to 6,000, still more preferably 2,000 to 5,000. The polylactic acid-based segment of the block copolymer plasticizer is such that L-lactic acid is 95 to 100% by mass or D-lactic acid is 95 to 100% by mass in 100% by mass of the segment. This is a preferred embodiment because bleeding out is suppressed.

  In addition, when the polylactic acid-based resin film containing the block copolymer plasticizer is made porous by processing such as stretching, it contains a plasticizer that does not form a eutectic with the polylactic acid-based resin. In comparison, the moisture permeability is greatly excellent. This is because the eutectic formed improves the hole forming efficiency during processing such as stretching described later.

  In 100% by mass of the block copolymer plasticizer, the mass ratio of the polylactic acid-based segment is preferably 5% by mass to 45% by mass, and the mass ratio of the polyether-based segment is 55% by mass to 95% by mass. It is a preferable aspect.

  Further, the number average molecular weight of the polyether segment in one molecule of the block copolymer plasticizer is preferably 5,000 to 20,000. By making the number average molecular weight within the above range, the composition constituting the film has sufficient moisture permeability and elongation at break, and is melted when a composition containing polylactic acid resin (A) is obtained. The viscosity can be adjusted to an appropriate level, and processing such as ejection and stretching during film formation can be stabilized.

  As an order constitution in the block copolymer of each segment of the polyether-based segment and the polylactic acid-based segment, from the viewpoint of more effectively suppressing bleed out, at least one of the block copolymer plasticizer molecules. There is preferably a polylactic acid-based segment at the end. The most preferred embodiment is that the polylactic acid-based segment is at both ends of the block copolymer plasticizer molecule.

The block copolymer plasticizer can be synthesized by ring-opening addition polymerization of lactide to polyalkylene glycol. Since polyalkylene glycol usually has hydroxyl groups at both ends, if the reaction proceeds sufficiently, a block copolymer of polylactic acid-polyalkylene glycol-polylactic acid type can be obtained substantially. The polyether segment of the plasticizer is made of polyalkylene ether because it can give the desired flexibility with a smaller amount of addition, and contributes to improving the moisture permeability of the processed porous film because it is a hydrophilic component. It is preferable to have a segment. Specific examples of the polyether segment include polyalkylene ether segments made of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol / polypropylene glycol copolymer, and the like. Among these, from the viewpoint of improving flexibility and moisture permeability, a polyalkylene ether segment made of polyethylene glycol is most preferably used.

  When the polylactic acid-based resin film of the present invention contains an organic component (B), the content of the organic component (B) in 100% by mass of all components of the polylactic acid-based resin film is flexible, bleed-out resistance, and stretched. From the viewpoint of moisture permeability after processing such as, it is preferably 10 to 80% by mass, more preferably 15 to 50% by mass, and still more preferably 20 to 45% by mass.

(Combination of organic components (B))
In the polylactic acid-based resin film of the present invention, the organic component (B) may be combined from the viewpoint of moisture permeability after processing such as biodegradability, flexibility, bleed-out resistance, and stretching. It is preferable to include at least one selected from the group consisting of biodegradable agents (BP) and biodegradable resins other than plasticizers. More specifically, a block copolymer having a polyether segment and a polylactic acid segment, a polyester resin obtained from an aliphatic diol and an aliphatic dicarboxylic acid, an aliphatic diol, an aliphatic dicarboxylic acid and an aliphatic hydroxy It preferably contains at least one selected from the group consisting of polyester resins obtained from carboxylic acids, and polyester resins obtained from aliphatic diols, aliphatic dicarboxylic acids and aromatic dicarboxylic acids.

  In particular, it includes a block copolymer having a polyether-based segment and a polylactic acid-based segment, and in addition, a polyester-based resin obtained from an aliphatic diol and an aliphatic dicarboxylic acid, an aliphatic diol, an aliphatic dicarboxylic acid, and a fatty acid. It is preferable to include at least one resin selected from the group consisting of polyester resins obtained from aliphatic hydroxycarboxylic acids and polyester resins obtained from aliphatic diols, aliphatic dicarboxylic acids, and aromatic dicarboxylic acids.

  A polyester resin obtained from an aliphatic diol and an aliphatic dicarboxylic acid, which is preferably used in combination with a block copolymer having a polyether segment and a polylactic acid segment, is a polybutylene succinate resin. Yes, polyester resin obtained from aliphatic diol, aliphatic dicarboxylic acid and aliphatic hydroxycarboxylic acid is polybutylene succinate lactide, and obtained from aliphatic diol, aliphatic dicarboxylic acid and aromatic dicarboxylic acid The polyester resin is poly (butylene adipate terephthalate).

  Of these, polybutylene succinate resins are most preferably used from the viewpoint of compatibility with polylactic acid resins and plasticizers.

  In the case where the organic component (B) is a combination of a plasticizer (BP) and a biodegradable resin, the mass of the polylactic acid resin film from the viewpoint of flexibility, bleed-out resistance and moisture permeability after processing such as stretching. The ratio is preferably (plasticizer (BP) / biodegradable resin) = (5/95) to (95/5), more preferably (10/90) to (80/20), More preferably, it is (20/80) to (60/40).

(Filler (C))
The polylactic acid-based resin film of the present invention preferably contains a filler (C) in order to become a porous film that becomes porous by processing such as stretching and exhibits good moisture permeability. The content of the filler (C) in 100% by mass of all components of the polylactic acid-based resin film is preferably 20% by mass or more and 70% by mass or less. When the filler (C) is less than 20% by mass, the moisture permeability after processing may be inferior, and when the filler (C) exceeds 70% by mass, the film is inferior in elongation at break. There is a possibility.

  Moreover, as for content of a filler (C), it is more preferable that it is 30-60 mass% in 100 mass% of all the components of a film, More preferably, it is 35-55 mass%.

  The filler (C) refers to a substance added as a base material for improving various properties, or an inert substance added for the purpose of increasing the volume, increasing the volume and reducing the cost of the product. As such a filler (C), an inorganic filler and / or an organic filler can be used.

  Examples of inorganic fillers include various carbonates such as calcium carbonate, various sulfates such as barium sulfate, various oxides such as zinc oxide, silicon oxide (silica), titanium oxide and alumina, and other such as aluminum hydroxide. Hydroxides, silicate minerals, hydroxyapatite, mica, talc, kaolin, clay, montmorillonite, various composite oxides such as zeolite, various phosphates such as calcium phosphate, various salts such as lithium chloride and lithium fluoride Can be used.

  Examples of organic fillers include oxalates such as calcium oxalate, terephthalates such as calcium, manganese and magnesium, and vinyl monomers such as divinylbenzene, styrene, acrylic acid and methacrylic acid. Fine particles made of coalescence, organic fine particles such as polytetrafluoroethylene, cellulosic powder such as wood powder and pulp powder, rice husk, wood chips, okara, waste paper pulverized materials, chip-shaped materials such as clothing pulverized materials, cotton fibers, Plant fibers such as hemp fibers and bamboo fibers, animal fibers such as silk and wool, polyester fibers, nylon fibers, and synthetic fibers such as acrylic fibers can be used.

  Among these fillers, calcium carbonate, barium sulfate, silicon oxide (silica), titanium oxide, mica, from the viewpoint of improving the moisture permeability of the film, maintaining mechanical properties such as strength and elongation, and reducing the cost. Talc, kaolin, clay, montmorillonite, and zeolite are preferably used, and calcium carbonate is particularly preferably used.

  The average particle size of the inorganic filler and the organic filler is preferably in the range of 0.01 to 10 μm. By setting the average particle size of the filler (C) to 0.01 μm or more, it becomes possible to highly fill the filler into the film, and as a result, the film has a high potential for increasing the porosity and moisture permeability of the film. Moreover, processability, such as extending | stretching of a film, becomes favorable by making an average particle diameter into 10 micrometers or less.

  The average particle diameter of the filler (C) is more preferably 0.1 to 8 μm, further preferably 0.5 to 5 μm, and most preferably 1 to 3 μm. Here, the average particle diameter is an average particle diameter of 50% cumulative distribution measured by a laser diffraction scattering method.

  The filler (C) used in the present invention can be treated with a surface treatment agent as necessary. Surface treatment agents used include phosphate ester compounds, fatty acids, resin acids, surfactants, fats and oils, waxes, carboxylic acid coupling agents, silane coupling agents, titanate coupling agents, and polymer surface treatments. An agent or the like can be used.

  By using a compound treated with these surface treatment agents as the filler (C), the affinity with the biodegradable resin (A) is improved, and it is effective in suppressing the aggregation of the filler and improving the dispersibility. Yes, the filler can be uniformly dispersed in the resin composition. As a result, by performing processing such as stretching, pores are uniformly formed, and a porous film excellent in moisture permeability and elongation at break can be obtained.

  Among these, as the surface treatment agent used in the filler (C) used in the present invention, a phosphate ester compound and / or a fatty acid is preferable, and from the viewpoint of improving the affinity with the polylactic acid resin (A). A phosphate ester compound is more preferably used.

(Additive)
The polylactic acid resin film of the present invention can contain additives other than the fillers described above within a range not impairing the effects of the present invention. For example, known lubricants, antioxidants, UV stabilizers, anti-coloring agents, matting agents, antibacterial agents, deodorants, flame retardants, weathering agents, antistatic agents, antioxidants, ion exchange agents, adhesiveness An imparting agent, an antifoaming agent, a color pigment, a dye, a crystal nucleating agent, a polymer chain extender, a polymer terminal blocking agent, and the like can be contained.

(DSC measurement)
The polylactic acid-based resin film of the present invention has an endothermic peak having a peak top in a temperature range of 20 ° C. or more and 60 ° C. or less in a spectrum obtained by DSC measurement of the film, and the heat quantity of the endothermic peak is 1 J / g or more. It is important that it is 20 J / g or less. When calculating the amount of heat of the endothermic peak, the amount of heat per gram is calculated using the organic component constituting the film, that is, the amount obtained by subtracting the amount of inorganic matter from all components as the mass unit. If the endothermic peak is within this range, the polylactic acid-based resin film can be processed while breaking the crystalline or amorphous stable structure by applying heat at a temperature of about 70 ° C. when processing such as stretching. Since it progresses, it becomes easy to obtain a porous film with a higher porosity, and also its moisture permeability becomes high.

  On the other hand, if the heat quantity of the endothermic peak is less than 1 J / g, the stress during processing such as stretching becomes too small, and the resulting film is not sufficiently porous, resulting in low moisture permeability. On the other hand, if the amount of heat at the endothermic peak exceeds 20 J / g, the stress during processing becomes too high, and it is easily broken. The amount of heat at the endothermic peak is preferably 3 J / g or more and 15 J / g or less, more preferably 5 J / g or more and 10 J / g or less.

  In order to set the heat quantity of this endothermic peak to 1 J / g or more and 20 J / g or less, the polylactic acid resin (A), the organic component (B), and the filler (C) are used as the above-mentioned preferable types and contents as described later. It is possible to achieve this by performing a manufacturing method, particularly a melt-kneading method using a side feeder, and an aging treatment.

(Temperature modulation DSC measurement)
The polylactic acid resin film of the present invention has a first glass transition temperature (Tg (1)) at a temperature of 40 ° C. or higher and 70 ° C. or lower in the spectrum of the reversible component obtained by temperature modulation DSC measurement of the film. And it is preferable to have a 2nd glass transition temperature (it is set as Tg (2)) in "Tg (1) -80" degreeC or more and "Tg (1) -20" degreeC or less. Similarly, in the spectrum of the reversible component obtained by temperature-modulated DSC measurement of the film, the third glass transition temperature (Tg (3)) between “Tg (2) -100” ° C. and “Tg (2) -10” ° C. Is a more preferable embodiment. And it is preferable that Tg (3) is -80 degreeC or more and -10 degrees C or less.

Tg (1) is more preferably 50 ° C. or higher and 70 ° C. or lower, and Tg (2) is more preferably “Tg (1) −70” ° C. or higher and “Tg (1) -40” ° C. or lower. Preferably, Tg (3) is more preferably “Tg (2) -50” ° C. or higher and “Tg (2) -20” ° C. or lower. And it is more preferable that Tg (3) is −50 ° C. or more and −15 ° C. or less.
As the origin of these three glass transition temperatures, Tg (1) is preferably a glass transition temperature derived from the polylactic acid resin (A), and Tg (3) is a glass transition temperature derived from the organic component (B). It is preferable that Tg (2) is preferably a glass transition temperature derived from a compatible component of the polylactic acid resin (A) and the organic component (B). In this case, the organic component (B) is more preferably a plasticizer (BP).
In a spectrum obtained by temperature-modulated DSC measurement of a film, a certain glass transition temperature (referred to as glass transition temperature (X)) is derived from a certain component (referred to as component (y)). The glass transition temperature (referred to as glass transition temperature (Y)) obtained from the temperature-modulated DSC measurement is close to the glass transition temperature (X), specifically, the absolute value of the difference between them is within 10 ° C., preferably Is determined by being within 7 ° C, more preferably within 5 ° C. In addition, a certain glass transition temperature (referred to as glass transition temperature (X)) is derived from a compatible component of one component (referred to as component (y)) and another component (referred to as component (z)). For glass transition temperature (glass transition temperature (Y)) obtained from temperature-modulated DSC measurement of component (y) alone, and glass transition temperature (glass) obtained from temperature-modulated DSC measurement of component (z) alone. The glass transition temperature (X) between them and the component (y) is a plasticizer of the component (z) (or the component (z) is y) a plasticizer). The criteria for determining the plasticizer are as described above.

  Furthermore, the ratio ΔCp2 / ΔCp1 between the specific heat difference before and after the second glass transition (referred to as ΔCp2) and the specific heat difference before and after the first glass transition (referred to as ΔCp1) is 0.01 or more and 1 or less. preferable. The second glass transition is preferably a glass transition derived from a compatible component of the polylactic acid resin (A) and the organic component (B), and the first glass transition is a polylactic acid resin (A). The glass transition derived from is preferable.

  Usually, in the spectrum of the reversible component obtained by the temperature modulation DSC measurement of the resin composition obtained by melt-kneading the polylactic acid resin (A) and the plasticizer (BP), it is derived from the polylactic acid resin (A). The glass transition is not confirmed, or the specific heat difference ΔCp1 before and after the glass transition is observed to be very small. Only the glass transition derived from the compatible component of the polylactic acid resin (A) and the plasticizer (BP) is observed, or the specific heat difference ΔCp2 before and after the glass transition derived from the compatible component is observed to be larger. The That is, ΔCp2 / ΔCp1 is 1 or more.

  In the spectrum of the reversible component obtained by temperature modulation DSC measurement of the resin composition obtained by melt-kneading the organic component (B) other than the polylactic acid resin (A) and the plasticizer (BP), polylactic acid Only two of the glass transition derived from the system resin (A) and the glass transition derived from the organic component (B) are observed, and there is no compatible component of both. Therefore, ΔCp2 / ΔCp1 is zero.

  On the other hand, in the polylactic acid-based resin film of the present invention, an amorphous structure in the polylactic acid-based resin film is obtained by performing an aging treatment using a manufacturing method described later, particularly a melt-kneading method using a side feeder. By controlling, ΔCp2 / ΔCp1 becomes 0.01 or more and 1 or less, and a porous film excellent in moisture permeability can be obtained by processing the polylactic acid resin film such as stretching. I found out. Since the specific heat difference before and after the glass transition of each component is a value proportional to the movable amorphous amount of each component, the specific heat difference before and after the glass transition of each component can be adjusted by controlling the amorphous structure. ΔCp2 / ΔCp1 is more preferably 0.01 or more and 0.6 or less, further preferably 0.05 or more and 0.4 or less, and particularly preferably 0.05 or more and 0.2 or less.

  When the plasticizer is composed of both a segment that contributes to plasticization of the polylactic acid resin (A) and a segment that does not contribute to plasticization, such as the block copolymer plasticizer described above, it contributes to plasticization. Only the glass transition temperature of the segment and the specific heat difference before and after the glass transition are handled. In the example of the block copolymer plasticizer, only the glass transition temperature of the polyether segment and the specific heat difference before and after the glass transition are handled, and the glass transition temperature of the polylactic acid segment and the specific heat difference before and after the glass transition are not handled.

When the polylactic acid resin film of the present invention contains a plasticizer (BP) as the organic component (B), the following i) or ii) in the spectrum of the reversible component obtained by temperature modulation DSC measurement of the film: It is preferable to satisfy any of the requirements.
i) The plasticizer (BP) does not have an endothermic peak of melting.
ii) The polylactic acid resin (A) and the plasticizer (BP) have an endothermic peak of melting, and the heat of fusion (referred to as ΔHmBP) at the endothermic peak of the melting of the plasticizer (BP) and the polylactic acid resin (A) The ratio ΔHmBP / ΔHmA of the heat of fusion (referred to as ΔHmA) at the endothermic peak of melting of 0.1 is 0.1 or less.

  The fact that the plasticizer (BP) does not show an endothermic peak of melting indicates that the plasticizer (BP) is not crystallized in the polylactic acid resin film. Moreover, that ΔHmBP / ΔHmA is 0.1 or less means that the amount of crystals of the plasticizer (BP) is sufficiently smaller than the amount of crystals of the polylactic acid resin (A). If the plasticizer is not crystallized in the film or if the amount of crystals is sufficiently small, the proportion of the plasticizer contributing to the softening of the polylactic acid resin increases. The lower limit of ΔHmBP / ΔHmA is 0, which corresponds to a case where ΔHmBP is 0, that is, when there is no endothermic peak of melting of the plasticizer (BP). ΔHmBP / ΔHmA is more preferably 0.05 or less, and further preferably 0.03 or less. Further, in order to set ΔHmBP / ΔHmA to 0.1 or less, the amount and type of the plasticizer (BP) should be within the above-described preferable range, and when side feed of the plasticizer (BP) described later is performed, There is a method of setting the position of the feeder within a preferable range.

  When the plasticizer is composed of both a segment that contributes to plasticization of the polylactic acid resin (A) and a segment that does not contribute to plasticization, such as the block copolymer plasticizer described above, it contributes to plasticization. Only the heat of fusion of the segment is handled. In the example of the block copolymer plasticizer, only the heat of fusion of the polyether segment is handled, and the heat of fusion of the polylactic acid segment is not handled.

(Elongation at break)
The polylactic acid-based resin film of the present invention has a lower value of 200% of the elongation at break in the length direction and the elongation at break in the width direction in order to ensure processability for making the film porous. The above is preferable, and more preferably 220% or more. This value is preferably as high as possible, but the upper limit is about 1000% because of the composition of the polylactic acid resin film and the composition that becomes porous by processing. In order to make this value 200% or more, a method in which the polylactic acid resin (A), the organic component (B), and the filler (C) are set to the above-described preferable types and contents can be mentioned.

(Production method of polylactic acid resin film)
Next, the method for producing the polylactic acid resin film of the present invention will be specifically described.

  Resin composition (raw material) used for producing the polylactic acid resin film of the present invention, specifically, polylactic acid resin (A), organic component (B), filler (C), or other components In obtaining a resin composition containing, it is practically preferable to produce a resin composition by melt-kneading each component. As for the melt-kneading method, known mixers that are usually used such as a kneader, a roll mill, a Banbury mixer, and a single-screw or twin-screw extruder can be used. Among these, from the viewpoint of productivity, the use of a single screw or twin screw extruder is preferable, and the use of a twin screw extruder is most preferable.

  The temperature at the time of melt kneading is preferably 150 ° C. to 240 ° C., more preferably 160 ° C. to 210 ° C., further preferably 190 ° C. to 210 ° C. from the viewpoint of preventing the deterioration of the polylactic acid resin (A).

  Furthermore, in order to control the amorphous structure of the obtained polylactic acid-based resin film, it is preferable to use a twin screw extruder with a side feeder as the twin screw extruder used for melt kneading. In this case, the L / D of the twin screw extruder is preferably 20-100. And it is preferable to put raw materials other than a plasticizer (BP) from a main feeder, and to put a plasticizer (BP) from a side feeder. This makes it possible to control the time during which the plasticizer (BP) stays in the extruder and the degree of kneading of the polylactic acid resin (A) and the plasticizer (BP). Thus, the polylactic acid-type resin film which consists of a resin composition obtained can turn into a porous film which expresses favorable moisture permeability by processes, such as extending | stretching. The position of the side feeder is preferably a point where L / D is 3 or more and 30 or less, and more preferably 5 or more and 20 or less, as measured from the tip of the extruder.

  When producing the polylactic acid-based resin film of the present invention, when the resin composition is once pelletized, melt-kneaded again and extruded to form a film, the pellet is dried at a temperature of 60 to 100 ° C. for 2 hours or more. For example, the water content of the resin composition is preferably 500 ppm (mass basis) or less. Furthermore, it is preferable to reduce the content of moisture and low molecular weight substances in the resin composition by vacuum drying under a high vacuum with a degree of vacuum of 10 Torr or less. By reducing the moisture content and low molecular weight content, such as by reducing the moisture content of the resin composition to 500 ppm (mass basis) or less, the resin composition can be prevented from lowering due to hydrolysis of the resin during melt kneading, and the resin composition can be melted. The viscosity can be adjusted to an appropriate level, and the film forming process can be stabilized. From the same viewpoint, when pelletizing, it is preferable to use a twin-screw extruder with a vent hole and melt-extrusion while removing volatiles such as moisture and low molecular weight.

  The polylactic acid-based resin film of the present invention can be obtained, for example, by a known film production method such as a known inflation method or T-die casting method, using the resin composition obtained by the above-described method.

  When manufacturing the polylactic acid-type resin film of this invention by T die-casting method, the following methods are used, for example. The resin composition prepared by the method as described above is melt-extruded by a single screw extruder, discharged from a slit-shaped T die having a lip interval of 0.2 to 3 mm, and set to a surface temperature of 0 to 40 ° C. A polylactic acid-based resin film is obtained by closely adhering onto a metal cooling casting drum. The cylinder temperature at the time of melt extrusion is usually in the range of 150 to 240 ° C, and the temperature of the T die is preferably in the range of 150 to 190 ° C, more preferably in the range of 150 to 180 ° C. In close contact with the casting drum, for example, it is preferable to apply static electricity using a wire electrode having a diameter of 0.5 mm, or use an air knife, an air chamber, and a touch roll.

  It is also preferable from the viewpoint of productivity that the melt-kneaded resin composition is directly formed into a film without being pelletized. In this case, it is preferable to use a twin-screw extruder for melt kneading, and for the above-mentioned reasons, it is preferable to use a twin-screw extruder with a side feeder, and further, a twin-screw extruder with a vent hole. preferable.

  The polylactic acid resin film of the present invention is preferably subjected to an aging treatment after being produced by various methods. In the present invention, aging treatment refers to storing a film for a long time in a temperature environment within a specific range. The temperature of the aging treatment is preferably a temperature between Tg (1) and Tg (2), more preferably “Tg (2) +10” ° C. or higher and “Tg (1) -10” ° C. . The aging time is preferably 50 hours or more, more preferably 70 hours or more, and further preferably 100 hours or more. The upper limit of the aging time is preferably 1000 hours or less in view of the influence on the hydrolysis of the film and the productivity. By performing the aging treatment at the aforementioned temperature and time, the amorphous structure of the film, particularly the structure of the compatible component of the polylactic acid resin (A) and the plasticizer (BP) is controlled, and the film is made porous by processing such as stretching. A polylactic acid film suitable for obtaining a conductive film can be produced.

(Processing method for polylactic acid resin film)
Next, a specific method of roll stretching will be described as processing for making the polylactic acid resin film of the present invention into a porous film that exhibits good moisture permeability. Examples of other processing methods other than roll stretching include tenter stretching, gear stretching, embossing, or a combination thereof.

  In roll stretching, first, the polylactic acid resin film is transported on a heated roll to preheat the polylactic acid resin film to a temperature at which the polylactic acid resin film is roll-stretched. For preheating, auxiliary heating means such as an infrared heater can be used in combination. A preferable range of the stretching temperature is 40 to 110 ° C, more preferably 50 to 100 ° C, and further preferably 60 to 90 ° C. The polylactic acid-based resin film preheated in this way is stretched in one or two or more stages in the longitudinal direction of the film using a difference in peripheral speed between heating rolls to produce a stretched film. The total draw ratio is preferably 2.5 to 10 times, more preferably 3 to 8 times, and further preferably 3 to 6 times.

  Next, the stretched film thus obtained is heat-treated by passing it over a heated roll. A preferable heat treatment temperature in the heat treatment step is 40 to 110 ° C, more preferably 50 to 100 ° C. The heat treatment time is preferably in the range of 0.2 to 30 seconds. Moreover, when performing relaxation in the stretching direction after stretching, the relaxation rate is preferably 1 to 10%, more preferably 3 to 5%. Subsequently, the stretched film is cooled and wound up to obtain a porous film.

(Porous film)
In the present invention, the porous film refers to a film having a large number of pores therein, and specifically, a film having a porosity of 10% or more. The porosity is preferably 10 to 80% in terms of the balance between the high moisture permeability of the film and the strength. The porosity is more preferably 20 to 80%, and further preferably 30 to 70%.

  The achievement means for setting the porosity to 10 to 80% is the production method described above with the polylactic acid resin (A), the organic component (B) and the filler (C) as the preferred types and contents described above. In particular, a melt-kneading method using a side feeder and an aging treatment are performed, and the preferred processing method described above is used.

(Moisture permeability)
The porous film obtained by the processing method described above preferably has a moisture permeability of 500 g / (m ² · day) or more. If the moisture permeability is less than 500 g / (m ² · day), the moisture permeability is insufficient, and condensation may occur on the high humidity side when the porous film is used as a moisture permeable material. The moisture permeability is more preferably 700 g / (m ² · day) or more, further preferably 1,000 g / (m ² · day) or more, and particularly preferably 1,500 g / (m ² · day) or more. It is. The upper limit of moisture permeability is not particularly limited, but is 10,000 g / (m ² · day) or less from the characteristics of the resin used and the processing method.

As a method for setting the moisture permeability to 500 g / (m ² · day) or more, the polylactic acid resin (A), the organic component (B) and the filler (C) are used as the above-mentioned preferable types and contents. The above-mentioned production method, in particular, a melt-kneading method using a side feeder and an aging treatment, and a preferred processing method described above are used.

(Elastic modulus)
The porous film obtained by the above processing preferably has a higher value of the elastic modulus in the length direction and the elastic modulus in the width direction of 200 MPa or more and 1000 MPa or less. When this value is less than 200 MPa, the porous film is too soft, so that it may be difficult to handle when processing such as bonding with another member. Moreover, when this value exceeds 1000 MPa, the waist of the porous film is too strong, which may make it unsuitable as a back sheet, clothing material, packaging material, or the like for absorbent articles. This value is more preferably 250 MPa or more and 800 MPa or less, and further preferably 300 MPa or more and 600 MPa or less. In order to make this value 200 MPa or more and 1000 MPa or less, there is a method in which the polylactic acid resin (A), the organic component (B), and the filler (C) are set to the preferred types and contents described above.

  The polylactic acid-based resin film of the present invention is preferably used as a processing film for obtaining a porous film that exhibits good moisture permeability, and the obtained porous film mainly includes flexibility, bleed-out resistance and Bed sheets, pillow covers, medical materials and hygiene materials such as back sheets for absorbent articles such as sanitary napkins and paper diapers, clothing materials such as rainy clothes and gloves, garbage bags and compost bags, Or it can use preferably for packaging materials, such as a bag for foodstuffs, such as vegetables and fruits, and a bag of various industrial products.

Next, the polylactic acid-based resin film porous film of the present invention will be described more specifically with reference to examples, but the present invention is not limited thereby.
[Measurement method and evaluation method]
The measurement methods and evaluation methods shown in the examples were performed under the following conditions.
(1) DSC measurement The DSC measurement of the film sample was performed on the following conditions using Q1000 made from TA Instruments. “Universal Analysis 2000” manufactured by TA Instruments was used for data processing.
・ Atmosphere: Nitrogen flow (50 mL / min)
Temperature and calorimetric calibration: high purity indium (Tm = 156.61 ° C., ΔHm = 28.70 J / g)
・ Specific heat calibration: Sapphire ・ Temperature range: About -50 to 200 ° C
・ Temperature increase rate: 10 ° C./min ・ Sample amount: about 5 mg
Sample container: Standard aluminum container.

From the obtained spectrum, the calorific value of an endothermic peak having a peak top at a temperature of 20 ° C. or higher and 60 ° C. or lower was calculated. The unit of heat amount here is J / g, but the unit mass is not the mass of the entire film, but the mass of the entire film multiplied by x, which is the mass ratio of the organic components in the film. Moreover, x which is the mass ratio of the organic component in the film was calculated according to the following formula from the mass b remaining as a result of the measurement by the calorimeter measuring device under the following conditions and the mass a before the measurement.
-Mass ratio of organic components x = (ab) / a
[Conditions for measurement with a calorimeter measuring device]
・ Device: TGA-50 (manufactured by Shimadzu Corporation)
・ Temperature increase rate: 20 ° C./min ・ Starting temperature: 23 ° C.
・ End temperature: 600 ℃
Atmosphere: Flow rate 20 mL / min under air atmosphere.

Using the value of the calorific value of the endothermic peak, the following criteria were used for evaluation.
A: 5 J / g or more and 10 J / g or less B: 3 J / g or more and less than 5 J / g or more than 10 J / g and 15 J / g or less Δ: 1 J / g or more and less than 3 J / g or more than 15 J / g or more than 20 J / g or less X: Less than 1 J / g or more than 20 J / g (2) Temperature-modulated DSC measurement Temperature-modulated DSC measurement of a film sample was performed under the following conditions using Q1000 manufactured by TA Instruments. “Universal Analysis 2000” manufactured by TA Instruments was used for data processing.
・ Atmosphere: Nitrogen flow (50 mL / min)
Temperature and calorimetric calibration: high purity indium (Tm = 156.61 ° C., ΔHm = 28.70 J / g)
・ Specific heat calibration: Sapphire ・ Temperature range: about -70 to 200 ° C
・ Rise rate: 2 ℃ / min ・ Temperature modulation amplitude: ± 1 ℃
・ Temperature modulation period: 60 seconds ・ Sample amount: Approximately 5 mg
Sample container: Standard aluminum container.

  From the temperature-modulated DSC curve of the reversible component, Tg (1), Tg (2), Tg (3), and ΔCp1 and ΔCp2 were determined. Further, ΔCp2 / ΔCp1 was calculated from the obtained ΔCp1 and ΔCp2. And by comparing with the glass transition temperature of the used raw material, it was confirmed to which raw material Tg (1), Tg (2) and Tg (3) originate. Tg (1) and Tg (3) were derived from substances having glass transition temperatures in the range of each temperature ± 15 ° C. When there are multiple candidates, it is assumed that they are derived from all of them. In addition, for Tg (2), a substance having a glass transition temperature is not included in the temperature range of ± 15 ° C., and between the glass transition temperatures of the polylactic acid resin (A) and the plasticizer (BP). It was determined that it was derived from a compatible component of the polylactic acid resin (A) and the plasticizer (BP). When the plasticizer (BP) does not show a glass transition temperature, it is confirmed that Tg (2) is lower than Tg (1), and the phase between the polylactic acid resin (A) and the plasticizer (BP) is confirmed. It was judged that it was derived from dissolved components.

Using the value of ΔCp2 / ΔCp1, evaluation was made according to the following criteria.
◎: 0.05 or more and 0.2 or less ○: 0.01 or more and less than 0.05 or more than 0.2 and 0.6 or less Δ: More than 0.6 and 1 or less ×: Less than 0.01 or more than 1 When the plasticizer (BP) was included as the organic component (B), ΔHmA and ΔHmBP were obtained from the temperature-modulated DSC curve of the reversible component, and ΔHmBP / ΔHmA was calculated from the obtained ΔHmA and ΔHmBP. When the plasticizer (BP) does not have an endothermic peak of melting, ΔHmBP / ΔHmA was assumed to be 0 regardless of the magnitude of ΔHmA.

Using the value of ΔHmBP / ΔHmA, the following criteria were used for evaluation.
◎: 0 or more and 0.03 or less ○: 0.03 or more and 0.05 or less Δ: 0.05 or more and 0.1 or less ×: More than 0.1 (3) Elastic modulus of porous film manufactured by Orientec Co., Ltd. Using TENSILON UCT-100, the elastic modulus of the porous film was measured in an atmosphere at a room temperature of 23 ° C. and a relative humidity of 65%.

Specifically, a sample cut into a strip shape having a length of 150 mm in the measurement direction and a width of 10 mm, a method defined in JIS K-7127 (1999) at an initial tensile chuck distance of 50 mm and a tensile speed of 200 mm / min. Accordingly, the measurement was performed 10 times in the length direction, and the average value was taken as the elastic modulus in the length direction. Similarly, the elastic modulus in the width direction was also measured.
(4) Processing test of polylactic acid resin film The polylactic acid resin film was stretched by a roll-type stretching machine. Specifically, the polylactic acid-based resin film is stretched three times in the length direction at a preheating temperature of 70 ° C. and a stretching temperature of 70 ° C., once cooled on a cooling roll and then heat-treated through a roll at a temperature of 70 ° C., After cooling again on the cooling roll, the film was wound up to collect a porous film.

(5) Porosity of porous film (%)
The porous film after the processing test was cut into a size of 30 mm × 40 mm and used as a sample. Using an electronic hydrometer (SD-120L manufactured by Mirage Trading Co., Ltd.), the specific gravity was measured in an atmosphere having a room temperature of 23 ° C. and a relative humidity of 65%. The measurement was performed three times, and the average value was defined as the specific gravity ρ of the film.

Next, the measured porous film was hot-pressed at a temperature of 220 ° C. and 5 MPa, and then rapidly cooled with water at a temperature of 25 ° C. to prepare a sheet in which the pores were completely erased. The specific gravity of this sheet was measured in the same manner as described above, and the average value was defined as the specific gravity d. From the specific gravity ρ of the film and the specific gravity d of the sheet, the porosity was calculated by the following formula.
Porosity (%) = [(d−ρ) / d] × 100.

(6) Moisture permeability of porous film About the porous film after the processing test, according to the method specified in JIS Z0208 (1976), using a constant temperature and humidity device set at 90% RH at a temperature of 25 ° C. The moisture permeability (g / (m ² · day)) was measured.

(7) Elongation at break of polylactic acid-based resin film Using TENSILON UCT-100 manufactured by Orientec, the elongation at break of polylactic acid-based resin film was measured in an atmosphere at room temperature of 23 ° C and relative humidity of 65%. .

  Specifically, a sample was cut out in a strip shape having a length of 150 mm and a width of 10 mm in the measurement direction, and the distance between the initial tensile chucks was 50 mm and the tensile speed was 200 mm / min, according to the method defined in JIS K-7127 (1999). Ten measurements were performed in the length direction, and the average value was defined as the elongation at break. Similarly, the elongation at break in the width direction was also measured.

[Polylactic acid resin (A)]
(A1) Polylactic acid resin:
Mass average molecular weight = 200,000, D-form content = 1.4 mol%, melting point = 166 ° C., glass transition temperature = 63 ° C., biodegradability = 99% (40 days, JIS K-6955-2 (2010) ) Crystalline polylactic acid resin.

The melting point was determined by DSC measurement after heating in a vacuum oven at a temperature of 100 ° C. for 5 hours. The conditions for DSC measurement were the same as those described in [Example] (1) DSC measurement. The melting points of the following raw materials were similarly measured.

  Moreover, said glass transition temperature was calculated | required by the temperature modulation DSC measurement. The conditions of the temperature modulation DSC measurement were the same as those described in “(2) Temperature modulation DSC measurement” above. Moreover, the glass transition temperature was similarly measured about the following raw material.

  Moreover, said mass average molecular weight measured by Japan Waters Co., Ltd. product Warters2690, polystyrene as a standard, column temperature of 40 degreeC, and the chloroform solvent. The mass average molecular weight was similarly measured about the following raw materials.

(A2) Polylactic acid resin:
Mass average molecular weight = 200,000, D-form content = 4.0 mol%, melting point = 153 ° C., glass transition temperature = 61 ° C., biodegradability = 99% (40 days, JIS K-6955-2 (2010) ) Crystalline polylactic acid resin.

(A3) Polylactic acid resin:
Mass average molecular weight = 120,000, D-form content = 1.4 mol%, melting point = 162 ° C., glass transition temperature = 62 ° C., biodegradation = 99% (40 days, JIS K-6955-2 (2010) ) Crystalline polylactic acid resin.

[Organic component (B)]
(B1) Polybutylene succinate resin:
Polybutylene succinate resin (trade name “GSPla” (registered trademark) FZ91PN, manufactured by Mitsubishi Chemical Corporation), melting point = 110 ° C., glass transition temperature = −33 ° C., biodegradability = 85% (40 days, JIS K-6653) -2 (2010)).

  The fact that the organic component (B1) is not a plasticizer (BP) indicates that when a temperature-modulated DSC measurement is performed on pellets obtained by melt-kneading under the following condition (D), the glass transition temperature is a polylactic acid resin. (A1) Judging from the fact that the temperature was not observed at a temperature of ± 20 ° C. between the simple substance and the organic component (B1) alone.

  Condition (D): A mesh of polylactic acid resin (A1) 50% by mass and organic component (B1) 50% by mass in the same direction as a meshing type with a vacuum vent with a cylinder diameter of 190 ° C. and a screw diameter of 44 mm and L / D = 40 It is supplied to the main hopper of the twin-screw extruder (the raw material is fed to the point of L / D = 40 as measured from the tip of the twin-screw extruder), melt-kneaded while degassing the vacuum vent, and pelletized. To obtain a composition.

(B2) Polybutylene adipate / terephthalate resin:
Polybutylene adipate terephthalate resin (trade name “Ecoflex” F Blend C1200, manufactured by BASF), melting point = 120 ° C., glass transition temperature = −30 ° C., biodegradability = 90% (80 days, JIS K-6953- 2 (2010)) biodegradable resin.

  The fact that the organic component (B2) is not a plasticizer (BP) indicates that when a temperature-modulated DSC measurement is performed on pellets obtained by melt-kneading under the above condition (D), the glass transition temperature is a polylactic acid resin. It was judged that the temperature was not observed at a temperature of ± 20 ° C. intermediate between (A1) simple substance and the organic component (B2) simple substance.

(B3) Block copolymer having a polylactic acid segment:
A mixture of 62 parts by mass of polyethylene glycol having a number average molecular weight of 8,000, 38 parts by mass of L-lactide, and 0.05 parts by mass of tin octylate, and a temperature of 160 ° C. in a nitrogen atmosphere in a reaction vessel equipped with a stirrer. For 3 hours to obtain a block copolymer plasticizer having polylactic acid segments having a number average molecular weight of 2,500 at both ends of polyethylene glycol having a number average molecular weight of 8,000. Biodegradability = 80% (300 days, JIS K-6955-2 (2010)) biodegradable plasticizer (BP). Melting point of polyethylene glycol segment contributing to plasticization of polylactic acid resin (A) = 86 ° C., glass transition temperature = −39 ° C.

  When the organic component (B3) is a plasticizer (BP), the temperature of the pellet obtained by melt-kneading under the above condition (D) is measured by a temperature-modulated DSC measurement. (A1) Judgment was made by observation at a temperature of ± 20 ° C. between the simple substance and the organic component (B2) alone.

(B4) Tributyl acetylcitrate:
Pfizer, trade name “Citroflex A-4”, melting point = −59 ° C., plasticizer without glass transition temperature (BP).

  When the organic component (B4) is a plasticizer (BP), the temperature of the pellet obtained by melt-kneading under the above condition (D) is measured by a temperature-modulated DSC measurement. Judgment was made based on observation at a temperature 30 ° C. lower than that of the resin (A1) alone.

[Filler (C)]
(C1) Calcium carbonate:
Calcium carbonate (manufactured by Ajinomoto Fine Techno Co., Ltd., trade name “Topflow H200”, average particle size 1.7 μm, surface treatment with phosphate ester compound).

(C2) Calcium carbonate:
Calcium carbonate (Sankyo Flour Mills, trade name “SCP-E # 2010”, average particle size 1.7 μm, surface treatment with stearic acid (a type of fatty acid)).

Example 1
A mixture of 15% by mass of polylactic acid resin (A1), 20% by mass of organic component (B1), 15% by mass of organic component (B3), and 50% by mass of filler (C1) is mixed with a screw diameter of 44 mm at a cylinder temperature of 190 ° C. , L / D = 40 mesh type co-axial twin screw extruder main hopper (feeding raw material to the point of L / D = 40 as measured from the tip of the twin screw extruder) Was melt-kneaded while degassing, homogenized and then pelletized to obtain a resin composition. There was no side feed.

  The pellets of the resin composition thus obtained were vacuum-dried at a temperature of 60 ° C. for 7 hours using a rotary drum type vacuum dryer. The pellet of the resin composition is supplied to a single screw extruder having a cylinder temperature of 190 ° C., extruded into a film shape at a T die die temperature of 190 ° C., and cast onto a drum cooled to a temperature of 20 ° C. to be a polylactic acid resin film Got. The obtained polylactic acid-based resin film was aged at 120 ° C. for 120 hours to obtain a polylactic acid-based resin film.

  An aging-treated polylactic acid resin film was processed by roll stretching. The polylactic acid-based resin film is preheated by being conveyed on a roll heated to a temperature of 70 ° C., and the difference in peripheral speed between the rolls heated to a temperature of 70 is used in one step in the longitudinal direction of the film. The film was stretched twice, and further heat treated by passing it over a roll heated to a temperature of 70 ° C., and the stretched film was cooled and wound up.

  Table 1 shows the evaluation results of the physical properties of the polylactic acid resin film obtained above and the physical properties of the processed film.

(Example 2)
A mixture of 15% by mass of polylactic acid resin (A1), 20% by mass of organic component (B1), and 50% by mass of filler (C1) was vacuum vented with a cylinder temperature of 190 ° C. and a screw diameter of 44 mm and L / D = 40. It is used for the main feeder of the meshing type co-directional twin-screw extruder (feeding the raw material at a point of L / D = 40 as measured from the tip of the twin-screw extruder), and subsequently 15% by mass of the organic component (B3), The same twin screw extruder side feeder (measured from the screw tip of the twin screw extruder and fed the raw material at a point of L / D = 15) was melt-kneaded while degassing the vacuum vent and homogenized. Later, pelletized to obtain a composition.

  The pellets of the composition thus obtained were vacuum-dried at a temperature of 60 ° C. for 7 hours using a rotary drum type vacuum dryer. Pellets of this composition were supplied to a single screw extruder with a cylinder temperature of 190 ° C., extruded into a film at a T die die temperature of 190 ° C., and cast onto a drum cooled to a temperature of 20 ° C. to obtain a polylactic acid resin film. Obtained. No aging treatment was performed.

  The obtained polylactic acid-based resin film was processed by roll stretching. The polylactic acid-based resin film is preheated by being conveyed on a roll heated to a temperature of 70 ° C., and the difference in peripheral speed between the rolls heated to a temperature of 70 is used in one step in the longitudinal direction of the film. The film was stretched twice, and further heat treated by passing it over a roll heated to a temperature of 70 ° C., and the stretched film was cooled and wound up.

  Table 1 shows the evaluation results of the physical properties of the polylactic acid resin film obtained above and the physical properties of the processed film.

(Example 3)
A mixture of 15% by mass of polylactic acid resin (A1), 20% by mass of organic component (B1), and 50% by mass of filler (C1) was vacuum vented with a cylinder temperature of 190 ° C. and a screw diameter of 44 mm and L / D = 40. It is used for the main feeder of the meshing type co-directional twin-screw extruder (feeding the raw material at a point of L / D = 40 as measured from the tip of the twin-screw extruder), and subsequently 15% by mass of the organic component (B3), The same twin screw extruder side feeder (measured from the screw tip of the twin screw extruder and fed the raw material at a point of L / D = 15) was melt-kneaded while degassing the vacuum vent and homogenized. Later, pelletized to obtain a resin composition.

  The pellets of the resin composition thus obtained were vacuum-dried at a temperature of 60 ° C. for 7 hours using a rotary drum type vacuum dryer. The pellet of the resin composition is supplied to a single screw extruder having a cylinder temperature of 190 ° C., extruded into a film shape at a T die die temperature of 190 ° C., and cast onto a drum cooled to a temperature of 20 ° C. to be a polylactic acid resin film Got. The obtained polylactic acid resin film was aged at a temperature of 20 ° C. for 120 hours.

  An aging-treated polylactic acid resin film was processed by roll stretching. The polylactic acid-based resin film is preheated by being conveyed on a roll heated to a temperature of 70 ° C., and the difference in peripheral speed between the rolls heated to a temperature of 70 is used in one step in the longitudinal direction of the film. The film was stretched twice, and further heat treated by passing it over a roll heated to a temperature of 70 ° C., and the stretched film was cooled and wound up.

  Table 1 shows the evaluation results of the physical properties of the polylactic acid resin film obtained above and the physical properties of the processed film.

(Examples 4 to 22)
A polylactic acid resin film was obtained in the same manner as in Example 3 except that the resin composition and production conditions were changed as follows, and this was processed by roll stretching in the same manner as in Example 3.
Example 4: The temperature of the aging treatment was changed to 40 ° C.
Example 5: The temperature of the aging treatment was changed to 10 ° C.
Example 6: The aging process time was changed to 60 hours.
Example 7: The aging process time was changed to 80 hours.
Example 8: The aging treatment time was changed to 500 hours.
Example 9: The position of the side feed was measured from the screw tip of the twin screw extruder and changed to a point of L / D = 30.
-Example 10: It changed into the composition which does not contain an organic component (B1) and increases the quantity of a polylactic acid-type resin (A1) and an organic component (B3).
Example 11: The organic component (B1) was changed to the organic component (B2).
Example 12: The organic component (B3) was changed to the organic component (B4).
-Example 13: It changed into the composition which decreased the quantity of an organic component (B1), and increased the quantity of a polylactic acid-type resin (A1) and an organic component (B3).
Example 14: The composition was changed to a composition in which the amount of the organic component (B1) was increased and the amount of the polylactic acid resin (A1) and the organic component (B3) was decreased.
Example 15: The composition was changed to a composition in which the amount of the filler (C1) was reduced and the amount of the polylactic acid resin (A1), the organic component (B1) and the organic component (B3) was increased.
Example 16: The amount of the filler (C1) was increased, and the composition was changed to reduce the amounts of the polylactic acid resin (A1), the organic component (B1), and the organic component (B3).
Example 17: The composition was changed to a composition in which the amount of the organic component (B3) was reduced and the amount of the polylactic acid resin (A1) and the organic component (B1) was increased.
Example 18: The amount of the organic component (B3) was increased, and the composition was changed to reduce the amount of the polylactic acid resin (A1) and the organic component (B1).
Example 19: The filler (C1) was changed to the filler (C2).
Example 20: The polylactic acid resin (A1) was changed to a polylactic acid resin (A2).
Example 21: The polylactic acid resin (A1) was changed to a polylactic acid resin (A3).
Example 22: The temperature of the aging treatment was changed to 55 ° C.
Tables 1 and 2 show the evaluation results of the physical properties of the polylactic acid resin film obtained above and the physical properties of the processed film.

(Comparative Example 1)
A mixture of 15% by mass of polylactic acid resin (A1), 20% by mass of organic component (B1), 15% by mass of organic component (B3), and 50% by mass of filler (C1) has a screw diameter of 190 ° C. 44mm, L / D = 40 meshing type co-axial twin screw extruder main hopper (feeding material to the point of L / D = 40 as measured from the tip of the twin screw extruder) for vacuum Melting and kneading while venting the vent part, homogenizing, and pelletizing to obtain a resin composition. There was no side feed.

  The pellets of the resin composition thus obtained were vacuum-dried at a temperature of 60 ° C. for 7 hours using a rotary drum type vacuum dryer. The pellets of the resin composition were supplied to a single screw extruder having a cylinder temperature of 190 ° C., extruded into a film at a T die die temperature of 190 ° C., and cast on a drum cooled to a temperature of 20 ° C. No aging treatment was performed.

  The obtained polylactic acid-based resin film was processed by roll stretching. The polylactic acid-based resin film is preheated by being conveyed on a roll heated to a temperature of 70 ° C., and the difference in peripheral speed between the rolls heated to a temperature of 70 is used in one step in the longitudinal direction of the film. The film was stretched twice, and further heat treated by passing it over a roll heated to a temperature of 70 ° C., and the stretched film was cooled and wound up.

  Table 3 shows the evaluation results of the physical properties of the polylactic acid-based resin film obtained above and the physical properties of the processed film.

(Comparative Examples 2 to 4)
A polylactic acid resin film was obtained in the same manner as in Example 1 except that the composition and production conditions were changed as follows, and this was processed by roll stretching in the same manner as in Example 1.
Comparative Example 2: The aging process time was changed to 10 hours.
-Comparative example 3: It changed into the composition which does not contain an organic component (B1) and an organic component (B3), and increases the quantity of a polylactic acid-type resin (A1).
-Comparative example 4: It changed into the composition which does not contain polylactic acid-type resin (A1) and an organic component (B3), and increases the quantity of an organic component (B1).

  Table 3 shows the evaluation results of the physical properties of the obtained polylactic acid resin film and the physical properties of the processed film.

(Comparative Example 5)
As production conditions, a polylactic acid resin film and a processed film were obtained in the same manner as in Example 3 except that the temperature of the aging treatment was changed to 65 ° C.
Table 3 shows the evaluation results of the physical properties of the obtained polylactic acid resin film and the physical properties of the processed film.

  In Tables 1 to 3, MD is the length direction, and TD is the width direction. Moreover, about Tg (2) origin, having derived from the compatible component of polylactic acid-type resin (A) and a plasticizer (BP) was described, for example as A1 + B3. On the other hand, about Tg (3) origin, since several components may correspond, it described like B1 and B3 in that case.

  In Comparative Example 3, there was only one glass transition temperature, so the glass transition temperature was described in the Tg (1) column for convenience. Similarly, in Comparative Example 4, there was only one glass transition temperature, so the glass transition temperature was described in the column of Tg (3) for convenience.

  In Example 1 where the aging process was performed and Example 2 where the side feed was performed, compared with Comparative Example 1 where the aging process and the side feed were not performed, the endothermic peak heat amount and ΔCp2 / ΔCp1 were more preferable values. The moisture permeability of the later film was excellent. Further, in Example 3 where the aging treatment and the side feed were performed, the endothermic peak heat amount and ΔCp2 / ΔCp1 were more suitable values, and the moisture permeability was further excellent.

  In Example 4 in which the temperature of the aging treatment was higher than that in Example 3, the moisture permeability was further improved. On the other hand, in Example 22 in which the temperature of the aging treatment was further increased as compared with Example 4, the endothermic peak heat quantity and ΔCp2 / ΔCp1 were not suitable values compared to Example 4, and the processing was performed as indicated by the elongation at break. The sex was slightly inferior. Further, in Comparative Example 5 in which the temperature of the aging treatment was further increased as compared with Example 22, the elongation at break was low and processing was impossible.

  In Example 5 in which the temperature of the aging treatment was lower than that in Example 3, the endothermic peak heat amount and ΔCp2 / ΔCp1 were not slightly suitable values as compared with Example 3, and the moisture permeability was slightly reduced.

  In Example 6 and Example 7 in which the time of the aging treatment was shortened compared to Example 3, the endothermic peak heat amount and ΔCp2 / ΔCp1 were not slightly suitable values compared to Example 3, and the moisture permeability was slightly reduced. On the other hand, in Example 8 in which the aging treatment time was extended as compared with Example 3, there was almost no change in the endothermic peak heat quantity, ΔCp2 / ΔCp1 and moisture permeability.

  In Example 9 in which the position of the side feed is changed to a position farther from the tip of the extruder than in Example 3, the endothermic peak heat amount and ΔCp2 / ΔCp1 are not slightly favorable values compared to Example 3, and the moisture permeability is low. It dropped a little.

  In Example 10 in which the organic component (B1) was removed from Example 3, the endothermic peak calorific value and ΔCp2 / ΔCp1 were not suitable values and moisture permeability decreased compared to Example 3.

  In Example 11 in which the organic component (B1) of Example 3 was used as the organic component (B2), the endothermic peak calorific value and ΔCp2 / ΔCp1 were not slightly suitable as compared with Example 3, and the moisture permeability was slightly reduced.

  In Example 12 in which the organic component (B3) of Example 3 was used as the organic component (B4), the endothermic peak calorific value and ΔCp2 / ΔCp1 were not slightly suitable as compared with Example 3, and the moisture permeability was slightly reduced.

  In Example 13, in which the amount of the organic component (B1) in Example 3 was reduced and the amount of the polylactic acid resin (A1) and the organic component (B3) was increased, the endothermic peak heat amount and ΔCp2 / ΔCp1 were compared with Example 3. Was not a suitable value, and the water vapor transmission rate was slightly reduced. Moreover, as shown by the elongation at break, the workability was slightly inferior.

  In Example 14 in which the amount of the organic component (B1) in Example 3 was increased and the amount of the polylactic acid resin (A1) and the organic component (B3) was decreased, the endothermic peak heat amount and ΔCp2 / ΔCp1 were compared with Example 3. Was not a suitable value, and the water vapor transmission rate was slightly reduced.

  In Example 14, in which the amount of the filler (C1) in Example 3 was reduced and the amounts of the polylactic acid resin (A1), the organic component (B1), and the organic component (B3) were increased, compared with Example 3, the endotherm The peak heat quantity and ΔCp2 / ΔCp1 were not suitable values, and the water vapor transmission rate was lowered.

  In Example 15 in which the amount of the filler (C1) in Example 3 was reduced and the amounts of the polylactic acid resin (A1), the organic component (B1), and the organic component (B3) were increased, compared with Example 3, the endotherm The peak heat quantity and ΔCp2 / ΔCp1 were not suitable values, and the water vapor transmission rate was lowered.

  In Example 16, in which the amount of the filler (C1) in Example 3 was increased and the amounts of the polylactic acid resin (A1), the organic component (B1), and the organic component (B3) were reduced, the fracture occurred compared to Example 3. As indicated by the point elongation, the workability was slightly inferior.

  In Example 17, in which the amount of the organic component (B3) in Example 3 was reduced and the amount of the polylactic acid resin (A1) and the organic component (B1) was increased, the endothermic peak heat amount was a suitable value as compared with Example 3. Not so, the water vapor permeability decreased a little.

  In Example 18, in which the amount of the organic component (B3) in Example 3 was increased and the amount of the polylactic acid resin (A1) and the organic component (B1) was decreased, ΔCp2 / ΔCp1 and ΔHmBP / ΔHmA compared to Example 3. Was not a suitable value, and the water vapor transmission rate was slightly reduced. In addition, the workability was slightly inferior as shown by the elongation at break.

  In Example 19 in which the filler (C1) of Example 3 was changed to the filler (C2), the workability was slightly inferior as shown in the elongation at break as compared with Example 3.

  Example 20 in which the polylactic acid resin (A1) of Example 3 was changed to the polylactic acid resin (A2) had substantially the same physical properties as Example 3.

  In Example 21 in which the polylactic acid resin (A1) of Example 3 was changed to the polylactic acid resin (A3), the workability was slightly inferior as shown by the elongation at break.

  In Comparative Example 2 in which the time of the aging treatment of Example 1 was changed to 10 hours, the endothermic peak heat amount and ΔCp2 / ΔCp1 were not suitable values as compared with Example 1, and the moisture permeability decreased.

  In Comparative Example 3, which does not contain the organic component (B1) and the organic component (B3) from the formulation of Example 1 and is changed to increase the amount of the polylactic acid resin (A1), no endothermic peak and ΔCp2 exist, Compared to Example 1, the water vapor transmission rate decreased. In addition, the workability was slightly inferior as shown by the elongation at break.

  In Comparative Example 4 in which the polylactic acid resin (A1) and the organic component (B3) are not included in the formulation of Example 1 and the amount of the organic component (B1) is increased, no endothermic peak and ΔCp2 exist, Compared to Example 1, the water vapor transmission rate decreased.

Claims (11)

  A film comprising a polylactic acid-based resin (A), which has an endothermic peak having a peak top in a temperature range of 20 ° C. or higher and 60 ° C. or lower in a spectrum obtained by DSC measurement of the film, and the amount of heat of the endothermic peak Is a polylactic acid-based resin film, characterized by being 1 J / g or more and 20 J / g or less.   Furthermore, in the spectrum of the reversible component obtained by the temperature-modulated DSC measurement of the film containing the organic component (B), the first glass transition temperature (referred to as Tg (1)) is in the temperature range of 40 ° C. or higher and 70 ° C. or lower. And having a second glass transition temperature (Tg (2)) in a temperature range of “Tg (1) −80” ° C. or higher and “Tg (1) −20” ° C. or lower, and second glass. The ratio ΔCp2 / ΔCp1 between the specific heat difference before and after the transition (referred to as ΔCp2) and the specific heat difference before and after the first glass transition (referred to as ΔCp1) is 0.01 to 1 inclusive. The polylactic acid resin film described.   In the spectrum of the reversible component obtained by temperature-modulated DSC measurement of the film, a third glass transition temperature (Tg (3)) in the temperature range of “Tg (2) -100” ° C. or higher and “Tg (2) -10” ° C. or lower. The polylactic acid resin film according to claim 2, which comprises   Tg (3) is -80 degreeC or more and -10 degrees C or less, The polylactic acid-type resin film of Claim 3 characterized by the above-mentioned.   The Tg (1) is a glass transition temperature derived from the polylactic acid resin (A), and the Tg (3) is a glass transition temperature derived from the organic component (B). Polylactic acid resin film. A plasticizer (BP) is included as the organic component (B), and the reversible component spectrum obtained by temperature-modulated DSC measurement of the film satisfies either of the following requirements i) or ii): The polylactic acid-type resin film in any one of 2-5.
i) The plasticizer (BP) does not have an endothermic peak of melting.
ii) The polylactic acid resin (A) and the plasticizer (BP) have an endothermic peak of melting, and the heat of fusion at the endothermic peak of melting of the plasticizer (BP) (referred to as ΔHmBP) and the polylactic acid resin (A) ) The ratio ΔHmBP / ΔHmA of the heat of fusion (referred to as ΔHmA) at the endothermic peak of melting) is 0.1 or less.   The filler (C) is further contained, and the content of the filler (C) in 100% by mass of all the components of the film is 20% by mass or more and 70% by mass or less. The polylactic acid-type resin film in any one. 8. The polylactic acid resin film according to claim 2, wherein the organic component (B) contains at least one selected from the following group.
[Group]: Block copolymer having polyether segment and polylactic acid segment, polyester resin obtained from aliphatic diol and aliphatic dicarboxylic acid, aliphatic diol, aliphatic dicarboxylic acid and aliphatic hydroxycarboxylic acid And a group of polyester resins obtained from aliphatic diols, aliphatic dicarboxylic acids and aromatic dicarboxylic acids.   The polylactic acid-type resin film in any one of Claims 1-8 used for the use for manufacturing a porous film.   The porous film obtained using the polylactic acid-type resin film in any one of Claims 1-9. The porous film according to claim 10, wherein the moisture permeability is 500 g / (m ² · day) or more.