JP2014162799A - Polylactic acid-based mulching film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polylactic acid-based mulching film having excellent flexibility, heat resistance, bleed-out resistance and durability, and further superior resistance to shrinkage with time, tear propagation resistance and total light transmittance necessary as a mulching film, while containing a large amount of filler.SOLUTION: The polylactic acid-based mulching film comprises a polylactic acid-based resin as a resin (A), a thermoplastic resin other than the polylactic acid-based resin as a resin (B), and a compound treated with a surface treatment agent as a filler (C), and is formed from a composition containing the resin (A) in an amount of 30-70 mass% and the resin (B) in an amount of 30-70 mass%, each based on 100 mass% of the total of the resins (A) and (B), and the filler (C) in an amount of 20-100 pts.mass to 100 pts.mass of the total of the resins (A) and (B).

Description

  The present invention is excellent in flexibility, heat resistance, bleed-out resistance and durability, and further contains shrinkage resistance, tear propagation resistance and total light transmittance required as a multi-film while containing a large amount of filler. The present invention relates to an excellent polylactic acid-based multifilm.

  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. As a measure against the former, various biodegradable resins, and as a measure against the latter, a resin made of biomass (plant-derived raw material) that does not give a new carbon dioxide load to the atmosphere even if it is incinerated has been extensively researched and developed. ing. Attention has been focused on polylactic acid that satisfies both requirements and is relatively advantageous in terms of cost. When polylactic acid is applied to soft film applications typified by polyolefins such as polyethylene, it lacks flexibility and impact resistance. Therefore, various attempts have been made to improve these properties and put them into practical use.

  In the field of multi-films, for example, Patent Document 1 discloses a film made of a composition containing a polylactic acid resin and a plasticizer and defining elongation, thickness, and thermal shrinkage. Patent Document 2 discloses a film having a polylactic acid resin and an inorganic filler. Furthermore, Patent Document 3 discloses a polylactic acid film having polylactic acid, an aliphatic aromatic polyester, a plasticizer, and an inorganic filler.

Furthermore, in Patent Document 4, a polylactic acid film excellent in workability for expressing moisture permeability is filled with a polylactic acid resin, a thermoplastic resin other than the polylactic acid resin, and a compound treated with a surface treatment agent. A polylactic acid film comprising a composition comprising an agent, wherein the polylactic acid resin includes a crystalline polylactic acid resin and an amorphous polylactic acid resin, and a mass ratio of each constituent material is defined It is disclosed.
JP 2009-138085 A JP 2005-263931 A JP 2002-327107 A WO2012 / 114810 pamphlet

  In the techniques described in Patent Documents 1 to 4, a flexible polylactic acid film with a large amount of filler added can be obtained, but the shrinkage with time, tear propagation resistance, and total light transmittance required as a multifilm are obtained. Was insufficient.

  In other words, flexible polylactic acid films with a large amount of filler added have been studied so far, but their shrinkage with time, tear propagation resistance, and total light transmittance are not sufficient as multifilms. However, the invention of a multi-film having excellent performance has not yet been achieved.

  Therefore, in view of the background of such prior art, the present invention is excellent in flexibility, heat resistance, bleed out resistance, durability, and further contains shrinkage resistance required as a multifilm while containing a large amount of filler, It is intended to provide a polylactic acid-based multifilm excellent in tear propagation resistance and total light transmittance.

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

Aspects of the present invention are as follows.
1) A film comprising a composition comprising a polylactic acid resin as the resin (A), a thermoplastic resin other than the polylactic acid resin as the resin (B), and a compound treated with a surface treating agent as the filler (C). ,
In a total of 100% by mass of the resin (A) and the resin (B), 30 to 70% by mass of the resin (A) and 30 to 70% by mass of the resin (B) are contained, and the resin (A) and the resin (B) A polylactic acid-based multifilm comprising a composition containing 20 to 100 parts by mass of a filler (C) with respect to 100 parts by mass in total.
2) The polylactic acid multifilm according to 1), wherein the polylactic acid resin includes a crystalline polylactic acid resin and an amorphous polylactic acid resin.
3) It consists of a composition containing 20 to 60 parts by mass of the filler (C) with respect to 100 parts by mass in total of the resin (A) and the resin (B), as described in 1) or 2) Polylactic acid based multi-film.
4) The polylactic acid according to any one of 1) to 3), wherein the shrinkage ratio after storage at 65 ° C. for 30 minutes is from −2% to 2% in both the length direction and the width direction. Multi film.
5) The tear propagation resistance in the length direction and the width direction is 10 N / mm or more, and the polylactic acid-based multifilm according to any one of 1) to 4).
6) The polylactic acid multifilm according to any one of 1) to 5), wherein the total light transmittance is 75% or more.
7) The polylactic acid-based multifilm according to any one of 1) to 6), wherein the surface treatment agent is a phosphate ester compound and / or a fatty acid.
8) The polylactic acid-based multifilm according to any one of 1) to 7), wherein the surface treatment agent includes a methacrylic acid ester group.
9) The resin (B) is at least one resin selected from the group consisting of a block copolymer having a polyether-based segment and a polylactic acid segment and a block copolymer having a polyester-based segment and a polylactic acid segment; In addition, the polylactic acid-based multifilm according to any one of 1) to 8), wherein the polylactic acid-based multifilm is composed of at least one resin selected from the group consisting of aliphatic polyester-based resins and aliphatic aromatic polyester-based resins.
10) As for the resin (B), the total mass ratio of a resin selected from the group consisting of an aliphatic polyester resin and an aliphatic aromatic polyester resin is a block copolymer having a polyether segment and a polylactic acid segment. The polylactic acid-based multifilm according to 9), which is more than the total mass ratio of a resin selected from the group consisting of a block copolymer having a coalescence and a polyester-based segment and a polylactic acid segment.

  According to the present invention, it has excellent flexibility, heat resistance, bleed out resistance, durability, and further contains a large amount of filler, but also has a shrinkage resistance with time, tear propagation resistance, total light transmission required as a multi-film. A polylactic acid-based multifilm excellent in rate is provided.

  The present invention is excellent in the above-mentioned problems, that is, flexibility, heat resistance, bleed out resistance and durability, and further contains shrinkage resistance, tear propagation resistance, As a result of intensive studies on a polylactic acid-based multifilm having excellent light transmittance, it has a composition comprising a specific resin and a filler, and further, by using a compound treated with a surface treatment agent as a filler. This is the first successful solution to the problem. That is, the present invention comprises a composition comprising a polylactic acid resin as the resin (A), a thermoplastic resin other than the polylactic acid resin as the resin (B), and a compound treated with a surface treatment agent as the filler (C). It is a film and contains 30 to 70% by mass of resin (A) and 30 to 70% by mass of resin (B) in a total of 100% by mass of resin (A) and resin (B). A polylactic acid-based multifilm comprising a composition containing 20 to 100 parts by mass of the filler (C) with respect to 100 parts by mass in total of (B).

Hereinafter, the polylactic acid multifilm of the present invention will be described.
(Polylactic acid based multi-film)
(Resin (A) (Polylactic acid resin))
It is important that the polylactic acid-based multifilm of the present invention is composed of a composition containing the resin (A). Here, the resin (A) means a polylactic acid resin. The polylactic acid-based resin is a polymer having an L-lactic acid unit and / or a D-lactic acid unit as main constituent components. 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.

  The term “poly L-lactic acid” as used in the present invention means that the content of L-lactic acid units is more than 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 referred to 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, if the content ratio of the D-lactic acid unit in the poly-L-lactic acid increases, the crystallinity of the poly-L-lactic acid becomes lower and becomes closer to an amorphous state. Conversely, the content ratio of the D-lactic acid unit in the poly-L-lactic acid. As the amount 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, if the content ratio of the L-lactic acid unit in the poly-D-lactic acid increases, the crystallinity of the poly-D-lactic acid becomes low and approaches an amorphous state. Conversely, the content ratio of the L-lactic acid unit in the poly-D-lactic acid. As the amount 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 a viewpoint for maintaining the mechanical strength of the composition. From 100 to 100 mol% of all lactic acid units, 80 to 100 mol% is preferable, and 85 to 100 mol% is more preferable.

  The crystalline polylactic acid resin referred to in the present invention is a case where the polylactic acid resin is sufficiently crystallized under heating and then measured with a differential scanning calorimeter (DSC) in an appropriate temperature range. This 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-based resin referred to in the present invention refers to a polylactic acid-based resin that does not exhibit a clear melting point when measured in the same manner.

  As will be described later, the composition constituting the polylactic acid-based multifilm of the present invention is a mixture of a crystalline polylactic acid resin and an amorphous polylactic acid resin as the polylactic acid resin of the resin (A). Is preferred.

  The polylactic acid resin used in the present invention may copolymerize other monomer units other than lactic acid. Other monomers include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, pentane. Glycol compounds such as erythritol, bisphenol A, polyethylene glycol, polypropylene glycol and polytetramethylene glycol, oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid , Isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, -Dicarboxylic acids such as sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid and other hydroxycarboxylic acids, caprolactone, valerolactone, Examples include lactones such as propiolactone, undecalactone, and 1,5-oxepan-2-one. The copolymerization amount of the other monomer units is preferably 0 to 30 mol%, based on 100 mol% of the whole monomer units in the polymer of the polylactic acid resin, and 0 to 10 mol%. More preferably. In addition, it is preferable to select the component which has biodegradability among the above-mentioned monomer units according to a use.

  Moreover, about the polylactic acid-type resin used by this invention, when a main component is poly L-lactic acid, poly D-lactic acid is mixed, when a main component is poly D-lactic acid, poly L-lactic acid is mixed a little. It is also preferable. This is because the stereocomplex crystal formed thereby has a higher melting point than a normal polylactic acid crystal (α crystal), so that the heat resistance of the film is improved. At this time, the mass average molecular weight of the polylactic acid mixed in a small amount is preferably smaller than the mass average molecular weight of the main component polylactic acid from the viewpoint of efficiently forming a stereocomplex crystal. The mass average molecular weight of the polylactic acid mixed in a small amount is preferably 0.5 to 50%, more preferably 1 to 40%, and more preferably 2 to 30% of the mass average molecular weight of the main component polylactic acid. More preferably it is.

  The mass average molecular weight of the polylactic acid resin used in the present invention is preferably 50,000 to 500,000, more preferably 80,000 to 400,000, in order to satisfy practical mechanical properties. More preferably, it is ˜300,000. The mass average molecular weight as used herein refers to a molecular weight calculated by a polymethyl methacrylate conversion method after measurement with a chloroform solvent by gel permeation chromatography (GPC).

  The production method of the polylactic acid-based resin will be described later in detail, but 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.

  Content of resin (A) contained in the composition which comprises the polylactic acid-type multifilm of this invention is 30-70 mass% in the sum total 100 mass% of resin (A) and resin (B) mentioned later. This is very important. When the total amount of the resin (A) and the resin (B) is 100% by mass, if the resin (A) is less than 30% by mass, heat resistance and bleed-out resistance are insufficient, and if it exceeds 70% by mass, flexibility and tear propagation Insufficient resistance. The content of the resin (A) is preferably 30 to 60% by mass and more preferably 35 to 50% by mass in a total of 100% by mass of the resin (A) and the resin (B) described later.

The content of the resin (A) in 100% by mass of the entire composition constituting the polylactic acid-based multifilm of the present invention is preferably 15 to 60% by mass, and more preferably 15 to 50% by mass. It is preferably 20 to 45% by mass, more preferably 20 to 40% by mass.
(Resin (B) (thermoplastic resin other than polylactic acid resin))
It is important that the polylactic acid-based multifilm of the present invention is composed of a composition containing the resin (B) in order to improve flexibility, shrinkage resistance with time, and tear propagation resistance. Here, the resin (B) is a thermoplastic resin other than the polylactic acid resin. Thermoplastic resins other than polylactic acid resins include polyacetal, polyethylene, polypropylene, polyamide, poly (meth) acrylate, polyphenylene sulfide, polyetheretherketone, polyester, polyurethane, polyisoprene, polysulfone, polyphenylene oxide, polyimide, polyether An imide, an ethylene / glycidyl methacrylate copolymer, a polyester elastomer, a polyamide elastomer, an ethylene / propylene terpolymer, an ethylene / butene-1 copolymer, a thermoplastic starch, a polymer containing starch, and various resin plasticizers can be used. .

  Specific examples of the polyester as the resin (B) include aromatic polyester resins such as polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate, poly (ethylene succinate / terephthalate), poly (butylene succinate / terephthalate), poly ( Aliphatic aromatic polyester resins such as butylene adipate / terephthalate), polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate-3hydroxyhexanoate), poly (3-hydroxybutyrate) (Rate 3-hydroxyvalerate), polycaprolactone, polybutylene succinate, poly (butylene succinate adipate), and other aliphatic polyester resins can be used. Among these, from the viewpoints of flexibility, resistance to shrinkage with time, tear propagation resistance, and biodegradability, the thermoplastic resin other than the polylactic acid resin as the resin (B) includes an aliphatic aromatic polyester resin. An aliphatic polyester resin is preferable.

  As a specific example of the polymer containing starch, Novamont's biodegradable resin “Matterby” and the like can be used.

  Specific examples of various resin plasticizers include polyesters such as polypropylene glycol and sebacic acid esters, polyalkylene ethers, ether esters, and acrylates.

In particular, in order to suppress bleed out and increase plasticization efficiency, the solubility parameter SP of the resin plasticizer that is the resin (B) contained in the composition constituting the polylactic acid-based multifilm is (16 -23) ^1/2 MJ / m ³ is preferable, and (17-21) ^1/2 MJ / m ³ is more preferable. The method for calculating the solubility parameter is described in P.A. Small, J.M. Appl. Chem. 3, 71 (1953). Among such resin-based plasticizers, the resin-based plasticizer as the resin (B) preferably has biodegradability from the viewpoint of maintaining the biodegradability of the entire film.

  For agricultural and forestry applications, considering the possibility of residual undegraded products remaining in compost / farmland temporarily, as a resin plasticizer as resin (B), the US Food and Sanitation Agency (FDA) And a plasticizer approved by the Sanitation Council for Polyolefins and the like.

  Furthermore, from the viewpoint of the bleed-out resistance of the plasticizer, the heat resistance of the film, and the blocking resistance, the resin-based plasticizer as the resin (B) used in the present invention has, for example, a number average molecular weight of 1,000 or more. Polyethylene glycol or the like is preferably solid at room temperature (20 ° C. ± 15 ° C.), that is, the melting point exceeds 35 ° C. Moreover, 150 degreeC is an upper limit at the point which matches melt processing temperature with thermoplastic resins other than polylactic acid-type resin and polylactic acid-type resin.

  From the same viewpoint, the resin plasticizer as the resin (B) used in the present invention is a block copolymer having a polyether segment and a polylactic acid segment, or a polyester segment and a polylactic acid segment. More preferably, it is a block copolymer. Here, the plasticizing component is a polyether segment or a polyester segment. Furthermore, a polyester-type segment means the segment which consists of polyesters other than polylactic acid. These block copolymers (hereinafter referred to as block copolymers having polyether-based segments and polylactic acid segments, and block copolymers having polyester-based segments and polylactic acid segments are collectively referred to as “block copolymers”. The “plasticizer” will be described below.

  The mass ratio of the polylactic acid segment contained in the block copolymer plasticizer is preferably 45% by mass or less of the entire block copolymer plasticizer, because a desired flexibility can be imparted with a smaller amount of addition, preferably 5 mass. % Or more is preferable from the viewpoint of suppressing bleed-out. 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 polylactic acid segment of the block copolymer plasticizer that is the resin (B) is 1,200 or more, the block copolymer plasticizer that is the resin (B) and the resin (A) (polylactic acid resin) A sufficient affinity is produced between the polylactic acid segment and a part of the polylactic acid segment is taken into a crystal formed from the resin (A) (polylactic acid resin) to form a so-called eutectic, The block copolymer plasticizer, which is the resin (B), is bonded to the resin (A), and the block copolymer plasticizer exhibits a great effect in suppressing bleed-out. As a result, the blocking resistance of the film is also excellent. The number average molecular weight of the polylactic acid segment in the block copolymer plasticizer is more preferably 1,500 to 6,000, and further preferably 2,000 to 5,000. In addition, the polylactic acid segment which the block copolymer plasticizer has is that L-lactic acid is 95 to 100% by mass or D-lactic acid is 95 to 100% by mass. Therefore, it is preferable.

  As described above, the resin (A) is a polylactic acid-based resin, and the polylactic acid-based resin is a polymer mainly composed of an L-lactic acid unit and / or a D-lactic acid unit. Is a resin in which the mass proportion of lactic acid units is the maximum in 100% by mass of the polymer. Therefore, at least the mass ratio of the lactic acid unit in the block copolymer plasticizer that is the resin (B) is the second mass ratio of the lactic acid unit in 100 mass% of the block copolymer plasticizer that is the resin (B). It means that the mass ratio of the polyether segment or the polyester segment is maximum. Preferably, in 100% by mass of the block copolymer plasticizer that is the resin (B), the mass ratio of the lactic acid unit is 5 mass% to 45 mass%, and the mass ratio of the polyether segment or the polyester segment is 55 mass%. It is mass%-95 mass%.

  In addition, the plasticizing component of the block copolymer plasticizer which is the resin (B) is a polyether segment or a polyester segment. The polyether segment is more flexible with a small amount of addition. It is preferable from a viewpoint which can provide. Furthermore, from the same viewpoint, it is more preferable to have a segment made of polyalkylene ether as the polyether segment. Specifically, examples of the polyether-based segment include a segment made of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol / polypropylene glycol copolymer, and the like. In particular, a segment made of polyethylene glycol is a resin (A ) (Polylactic acid resin) has high affinity and is excellent in reforming efficiency, and is particularly preferable because desired flexibility can be imparted by adding a small amount of plasticizer.

  In addition, when the block copolymer plasticizer has a segment composed of a polyalkylene ether, the polyalkylene ether segment tends to be easily oxidized or thermally decomposed when heated at the time of molding, etc. It is preferable to use a hindered amine-based antioxidant or a phosphorus-based heat stabilizer in combination.

  When the block copolymer plasticizer has a polyester-based segment, polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate · 3-hydroxyvalerate), polycaprolactone, or ethylene glycol, Polyesters composed of aliphatic diols such as propanediol, butanediol, polyethylene glycol, and polypropylene glycol, and aliphatic dicarboxylic acids such as succinic acid, sebacic acid, and adipic acid are preferably used as the polyester-based segment.

  The block copolymer plasticizer may contain both components of the polyether segment and the polyester segment in one molecule, or may be either one of the components. From the viewpoint of plasticizer productivity, cost, and the like, when using any one component, it is preferable to use a polyether-based segment from the viewpoint that desired flexibility can be imparted by adding a smaller amount of the plasticizer. That is, a preferred embodiment as a block copolymer plasticizer is a block copolymer of a polyether segment and a polylactic acid segment.

  Furthermore, the number average molecular weight of the polyether segment or the polyester segment in one molecule of the block copolymer plasticizer is preferably 7,000 to 20,000. By setting it as the above range, the composition constituting the polylactic acid-based multifilm has sufficient flexibility, and the melt viscosity is reduced when the composition containing the resin (A) (polylactic acid-based resin) is used. The film forming processability such as the inflation film forming method can be stabilized at an appropriate level.

  There is no particular limitation on the order configuration of each segment block of the polyether-based and / or polyester-based segment and the polylactic acid segment, but at least one block of the polylactic acid segment is blocked from the viewpoint of more effectively suppressing bleed out. It is preferably at the end of the copolymer plasticizer molecule. Most preferably, the block of polylactic acid segment is at both ends of the block copolymer plasticizer molecule.

  Next, the case where polyethylene glycol having a hydroxyl terminal at both ends (hereinafter, polyethylene glycol is referred to as PEG) is employed as the polyether segment will be specifically described.

The number average molecular weight of PEG having hydroxyl ends at both ends (hereinafter, the number average molecular weight of _PEG is referred to as _MPEG ) is usually calculated from the hydroxyl value determined by a neutralization method or the like in the case of a commercially available product. In a system in which lactide w _L parts by mass are added to w _E parts by mass of PEG having hydroxyl groups at both ends, lactide is subjected to ring-opening addition polymerization at both hydroxyl groups of PEG and sufficiently reacted, so that PLA is substantially obtained. A block copolymer of the -PEG-PLA type can be obtained (PLA here indicates polylactic acid). This reaction is performed in the presence of a catalyst such as tin octylate as necessary. The number average molecular weight of one polylactic acid segment of this block copolymer plasticizer can be substantially determined as (1/2) × (w _L / w _E ) × M _PEG . The mass percentage of the total block copolymer plasticizer of the polylactic acid segment component can be substantially determined as _{100 × w L / (w L} + w E)%. Furthermore, the mass ratio of the plasticizer component excluding the polylactic acid segment component to the entire block copolymer plasticizer can be determined to be substantially 100 × w _E / (w _L + w _E )%.

  The purpose other than improving the flexibility, shrinkage resistance with time, and tear propagation resistance by the inclusion of the resin (B) depends on the type of the resin, for example, by improving the melt viscosity and the melt tension. Stabilization of bubble formation in process, improvement of high-temperature rigidity of polylactic acid-based multifilm by containing poly (meth) acrylate, impact resistance and toughness of polylactic acid-based multifilm by containing polyester, including starch Examples include promotion of biodegradability of polylactic acid-based multifilms by containing a polymer.

It is important that the content of the resin (B) in the composition constituting the polylactic acid-based multifilm of the present invention is 30 to 70% by mass in a total of 100% by mass of the resin (A) and the resin (B). It is. When it is less than 30% by mass, flexibility, shrinkage resistance with time, and tear propagation resistance are insufficient, and when it exceeds 70% by mass, heat resistance and bleed-out resistance are insufficient. Further, when traveling between rolls during film formation or during winding, tarmi and wrinkles are likely to occur, and the roll winding form and unwinding property may be poor. The content of the resin (B) is preferably 40 to 70% by mass and more preferably 50 to 65% by mass in a total of 100% by mass of the resin (A) and the resin (B).
(Combination of resin (B))
The polylactic acid-based multifilm of the present invention may contain only one kind of these resins (B), or may contain two or more kinds in combination. There is no restriction | limiting in particular in resin to combine, Thermoplastic resin groups other than the polylactic acid-type resin mentioned above as resin (B) can be combined, respectively. Among them, a combination of various resin-based plasticizers and a thermoplastic resin other than the resin-based plasticizer is preferable from the viewpoint of achieving both flexibility, resistance to shrinkage with time, and tear propagation resistance. Particularly in the present invention, when the resin (B) is a combination of various plastic plasticizers and a thermoplastic resin other than the resin plasticizer, flexibility, shrinkage resistance with time, and tear propagation resistance are dramatically improved. Found to improve.

  Among various plastic plasticizers, from the viewpoints of heat resistance, shrinkage resistance with time, tear propagation resistance, and bleed-out resistance, the above-mentioned block copolymer plasticizers, that is, polyether segments and polylactic acid segments It is preferable that the block copolymer has a block copolymer having a polyester-based segment and a polylactic acid segment. More preferably, it is a block copolymer having a polyether segment and a polylactic acid segment.

  Among thermoplastic resins other than resin-based plasticizers, aliphatic polyester resins and aliphatic aromatic polyester resins are preferable from the viewpoint of biodegradability. Examples of aliphatic polyester resins include polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate · 3-hydroxyvalerate), poly (3-hydroxybutyrate · 3-hydroxyhexanoate) ), Polycaprolactone, polybutylene succinate, and poly (butylene succinate adipate) are more preferable. Examples of aliphatic aromatic polyester resins include poly (ethylene succinate terephthalate), poly (butylene succinate terephthalate), Poly (butylene adipate terephthalate) is more preferred. Among these, from the viewpoint of flexibility, poly (3-hydroxybutyrate-3hydroxyhexanoate), poly (butylene succinate adipate), and poly (butylene adipate terephthalate) are more preferable.

  That is, in the present invention, the resin (B) is a block copolymer having a polyether segment and a polylactic acid segment, a block copolymer having a polyester segment and a polylactic acid segment, an aliphatic polyester resin, and an aliphatic group. A block copolymer having a polyether segment and a polylactic acid segment and a block copolymer having a polyester segment and a polylactic acid segment are preferable, although at least one resin selected from the group consisting of aromatic polyester resins is preferable. And at least one resin (resin-based plasticizer) selected from the group consisting of polymers, and at least one resin (resin-based plastics) selected from the group consisting of aliphatic polyester-based resins and aliphatic aromatic polyester-based resins. With other thermoplastics) It is more preferable that consists of not.

When the resin (B) contained in the polylactic acid-based multifilm of the present invention combines various resin-based plasticizers with a thermoplastic resin other than the resin-based plasticizer, it improves shrinkage resistance with time and tear propagation resistance. In view of the above, it is preferable that the mass ratio of the thermoplastic resin other than the resin-based plasticizer is larger than the mass ratio of the various resin-based plasticizers.
As described above, the thermoplastic resin other than the resin-based plasticizer is preferably a resin selected from the group consisting of an aliphatic polyester-based resin and an aliphatic aromatic polyester-based resin. A resin selected from the group consisting of a block copolymer having a polyether-based segment and a polylactic acid segment and a block copolymer having a polyester-based segment and a polylactic acid segment is preferable. Therefore, for the resin (B), the total mass ratio of the resin selected from the group consisting of an aliphatic polyester resin and an aliphatic aromatic polyester resin is a block copolymer having a polyether segment and a polylactic acid segment. The total mass ratio of the resin selected from the group consisting of a block copolymer having a coalesced and polyester-based segment and a polylactic acid segment is preferred.
When the resin (B) contained in the polylactic acid-based multifilm of the present invention combines various resin plasticizers and a thermoplastic resin other than the resin plasticizer, the mass ratio is (various resins Based plasticizer / thermoplastic resin other than resin based plasticizer) = (49/51) to (5/95), more preferably (45/55) to (20/80). Preferably, it is (45/55) to (30/70).
(Mixing of crystalline polylactic acid resin and amorphous polylactic acid resin)
The resin (A) (polylactic acid resin) contained in the composition constituting the polylactic acid multifilm of the present invention is preferably a mixture of a crystalline polylactic acid resin and an amorphous polylactic acid resin. . That is, it is preferable that the resin (A) (polylactic acid resin) includes a crystalline polylactic acid resin and an amorphous polylactic acid resin. By making resin (A) (polylactic acid resin) a mixture of crystalline polylactic acid resin and amorphous polylactic acid resin, the advantages of crystalline and amorphous polylactic acid resins can be obtained. This is because both can be achieved.

  As described above, the crystalline polylactic acid resin was measured with a differential scanning calorimeter (DSC) in an appropriate temperature range after the polylactic acid resin was sufficiently crystallized under heating. In this case, it refers to a polylactic acid resin in which a melting point derived from a polylactic acid component is observed.

  On the other hand, an amorphous polylactic acid-based resin refers to a polylactic acid-based resin that does not exhibit a clear melting point when the same measurement is performed.

  If the polylactic acid resin as the resin (A) does not contain a crystalline polylactic acid resin, the heat resistance of the film may be insufficient. In addition, when a block copolymer plasticizer is used as the above-mentioned various plasticizers, a co-crystal can be formed with the polylactic acid segment of the block copolymer plasticizer unless it contains a crystalline polylactic acid resin. Therefore, the bleed-out resistance may be insufficient.

  On the other hand, if the polylactic acid-based resin as the resin (A) does not contain an amorphous polylactic acid-based resin, the film may have insufficient flexibility, tear propagation resistance, shrinkage resistance with time, and bleed-out resistance. . This has the effect of not providing an amorphous portion in which the plasticizer can be dispersed.

  The crystalline polylactic acid resin used in the polylactic acid-based multifilm of the present invention is obtained from the viewpoint of improving heat resistance and blocking resistance, the content ratio of the L-lactic acid unit 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.

When the amount of the resin (A) in the composition constituting the polylactic acid-based multifilm of the present invention is 100% by mass (the total of the crystalline polylactic acid-based resin and the amorphous polylactic acid-based resin is 100% by mass The proportion of the crystalline polylactic acid resin is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and still more preferably 20 to 40% by mass.
(Filler (C))
It is important that the polylactic acid-based multifilm of the present invention comprises a composition containing a compound treated with a surface treatment agent as a filler (C) in order to improve the shrinkage resistance of the film over time. An inorganic filler and / or an organic filler can be used as the compound which is a precursor of the filler (C) and before being treated with the surface treatment agent.

  Here, an inorganic filler and / or an organic filler is a substance added as a base material in order to develop various properties, or an inert substance (inactive substance added for the purpose of increasing the volume, increasing the volume, reducing the cost of the product, etc.). Active inorganic compounds and organic compounds).

  Examples of inorganic fillers include various carbonates such as calcium carbonate, magnesium carbonate and barium carbonate, various sulfates such as magnesium sulfate, barium sulfate and calcium sulfate, zinc oxide, silicon oxide (silica), zirconium oxide and magnesium oxide. , Various oxides such as calcium oxide, titanium oxide, magnesium oxide, iron oxide, alumina, hydroxide such as aluminum hydroxide, magnesium hydroxide, silicate mineral, hydroxyapatite, mica, talc, kaolin, clay, montmorillonite, Zeolite, metal ion-carrying zeolite, wollastonite, potassium titanate, boroaluminum, zepiolite and other complex oxides, lithium phosphate, calcium phosphate, magnesium phosphate and other phosphates, lithium chloride, lithium fluoride, etc. Various salts Boron nitride, potassium titanate, metal phthalocyanine, activated carbon, charcoal, carbon black, can be used carbon fibers, carbon nanotubes, fullerene, graphite and the like.

  Examples of organic fillers include oxalates such as calcium oxalate, terephthalates such as calcium, barium, zinc, manganese and magnesium, vinyl monomers such as divinylbenzene, styrene, acrylic acid and methacrylic acid alone or Copolymer fine particles, polytetrafluoroethylene, benzoguanamine resin, thermosetting epoxy resin, unsaturated polyester resin, thermosetting urea resin, thermosetting phenol resin and other organic fine particles, wood powder and pulp powder Plants such as powder, rice husk, wood chip, okara, waste paper ground material, clothing ground material, cotton fiber, hemp fiber, bamboo fiber, wood fiber, kenaf fiber, jute fiber, banana fiber, coconut fiber, etc. Fiber, silk, wool, angora, cashmere, camel and other animal fibers, polyester fiber, nylon Wei, or the like can be used synthetic fibers such as acrylic fibers.

  Among the compounds (inorganic fillers and / or organic fillers) that are precursors of the filler (C) before being treated with the surface treatment agent, silicon oxide is used as a filler that exhibits blocking resistance. (Silica), talc, calcium carbonate, etc. As flame retardant fillers, aluminum hydroxide, magnesium hydroxide, etc. As UV fillers, zinc oxide, titanium oxide, etc., exhibit antibacterial properties As a filler, zeolite, metal ion (silver ion, etc.) supported zeolite, zinc oxide, titanium oxide, metal phthalocyanine, etc. As a filler that exhibits deodorizing properties, zeolite, metal ion (silver ion, etc.) supported zeolite, activated carbon, Bamboo charcoal, zepiolite, etc. can be used. Specific examples of zeolites exhibiting antibacterial properties and deodorizing properties and metal ion (eg, silver ions) -carrying zeolites include “Zeomic” series manufactured by Sinanen Zeomic.

  Among the compounds (inorganic fillers and / or organic fillers) that are the precursors of these fillers (C) before being treated with the surface treatment agent, the flexibility of the film, tear propagation resistance, and shrinkage with time From the viewpoints of properties and cost reduction, calcium carbonate, barium carbonate, barium sulfate, calcium sulfate, silicon oxide (silica), titanium oxide, mica, talc, kaolin, clay, and montmorillonite are preferable.

  The filler (C) of the present invention can be obtained by treating the aforementioned inorganic filler and / or organic filler with a surface treatment agent. Surface treatment agents used to obtain the filler (C) include phosphate ester compounds, fatty acids, resin acids, surfactants, fats and oils, waxes, carboxylic acid coupling agents, silane coupling agents, and titanate cups. Ring agents, polymer surface treatment agents, and the like can be used. By using the compound treated with these surface treatment agents as the filler (C), the affinity with the matrix resin is improved, and it is effective in suppressing the aggregation of the filler and improving the dispersibility. It becomes possible to uniformly disperse the filler. As a result, a film excellent in flexibility, tear propagation resistance and total light transmittance can be obtained.

  The surface treatment method is not particularly limited, but a method of physically mixing the surface treatment agent and the compound (inorganic filler and / or organic filler) before being treated with the surface treatment agent, toluene A method of mixing in a solvent such as can be employed. Among these, the method of physically mixing from a practical side is preferable. The physical mixing method is not particularly limited, and various pulverizers such as a roll rolling mill, a high-speed rotary pulverizer, a ball mill, a jet mill, etc. A method of surface treatment with a surface treatment agent while pulverizing a compound before treatment, or a container rotating mixer in which the container itself rotates, a container having rotating blades in a fixed container, or a container fixed mixer in which an air current is blown The method of surface-treating using etc. can be mentioned. Specifically, a mixer such as a nauta mixer, a ribbon mixer, or a Henschel mixer is preferable.

In addition, the treatment conditions at that time are not particularly limited, and when the filler (C) is added to and blended with the matrix resin (resin (A) and resin (B)), the matrix resin (resin (A) and resin) In view of the dispersibility of the filler (C) in (B)), the occurrence of foreign matters during high-temperature residence of the matrix resin (resin (A) and resin (B)), and the point of foaming, the treatment temperature is preferably 30 ° C. or higher. Further, it is preferably 50 ° C. or higher, particularly 90 ° C. or higher. The treatment time is preferably within 5 hours, more preferably within 3 hours, particularly preferably within 2 hours.

The filler (C) of the present invention is obtained by treating the inorganic filler and / or organic filler with a surface treatment agent, and the ratio of the inorganic filler and / or organic filler. It is preferable that the surface area S (m ² / g) and the mass ratio T (mass%) of the portion derived from the surface treatment agent in the filler (C) satisfy the following conditions.

Condition: 0.15 ≦ T / S ≦ 1.0
When T / S is 0.15 or more, the effect of the surface treatment agent described above can be maximized. T / S is more preferably 0.20 or more, and further preferably 0.25 or more. In addition, when T / S is 1.0 or less, it is possible to suppress degradation such as hydrolysis and oxidative degradation of the matrix resin (resin (A) and resin (B)) due to an excessive surface treatment agent. That is, it is preferable because durability is improved. T / S is more preferably 0.60 or less.

  When using a phosphate ester compound as a surface treatment agent, phosphate ester, phosphite ester, pyrophosphate ester and the like can be used as the phosphate ester compound. There may be two or more phosphorus atoms in one molecule, and it may be preferable to have an unsaturated bond in the molecule, and the unsaturated bond is a terminal double bond. May be preferred.

  When using a fatty acid as the surface treating agent, a saturated fatty acid such as stearic acid, an unsaturated fatty acid such as oleic acid, linoleic acid, and the like can be used as the fatty acid.

  As the resin acid, a resin having a carboxyl group in the terminal or main chain, such as maleic acid-modified polyolefin, can be used.

  When a surfactant is used as a surface treatment agent, an anionic surfactant such as fatty acid soap such as stearic acid soap or sulfonic acid soap, or a nonionic surfactant such as polyethylene glycol derivative should be used as the surfactant. Can do.

  When using fats and oils as a surface treating agent, soybean oil, linseed oil, etc. can be used as fats and oils.

  When wax is used as the surface treatment agent, carnauba wax, long-chain ester wax, polyethylene wax, polypropylene wax, and oxides or acid-modified products thereof can be used as the wax.

  When a carboxylic acid coupling agent is used as the surface treatment agent, carboxylated polybutadiene, carboxylated polyisoprene, or the like can be used as the carboxylic acid coupling agent.

  When a silane coupling agent is used as the surface treatment agent, vinyl trimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane are used as the silane coupling agent. N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and the like can be used.

  When a titanate coupling agent is used as a surface treatment agent, an organic functional group of alkyl group + amino group type, phosphite type, pyrophosphate type, carboxylic acid type, etc. is used as the titanate coupling agent. can do.

  When a polymer surface treatment agent is used as the surface treatment agent, a random or graft copolymer such as maleic anhydride-modified polyolefin, maleic anhydride-modified styrene-ethylene-butadiene-styrene copolymer is used as the polymer surface treatment agent. A polymer, a block copolymer such as propylene-acrylate, a hydrophobic group-hydrophilic group copolymer, and the like can be used.

  Among these, the surface treatment agent used in the filler (C) of the present invention is at least selected from a phosphate ester compound, a fatty acid, a resin acid, a surfactant, a silane coupling agent, and a titanate coupling agent. One compound is preferred. Among these, the surface treatment agent used for the filler (C) is more preferably a phosphate ester compound and / or a fatty acid.

  When at least either an aliphatic polyester resin or an aliphatic aromatic polyester resin is used as the thermoplastic resin other than the polylactic acid resin of the resin (B), a matrix resin (resin (A) + resin (B From the viewpoint of improving the affinity with)), it is preferable to use a phosphate ester compound as the surface treatment agent used in the filler (C) of the present invention.

  Moreover, it is preferable that the surface treating agent used when obtaining the filler (C) of this invention contains a methacrylic ester group. This is because the methacrylic acid ester group has a high affinity with polylactic acid in the matrix resin, so it has a higher effect on suppressing the aggregation of the filler and improving the dispersibility, and more uniformly disperses the filler in the resin composition. It is because it becomes possible to do. As a result, it becomes possible to obtain a film having more flexibility, tear propagation resistance, total light transmittance, and resistance to shrinkage with time. The methacrylic acid ester group is more preferably at the end in the surface treatment agent molecule.

Furthermore, the surface treatment agent used in obtaining the filler (C) of the present invention is at least selected from a phosphate ester compound, a fatty acid, a resin acid, a surfactant, a silane coupling agent, and a titanate coupling agent. It is preferable that it is one and further contains a methacrylic ester group. Among these, it is more preferable that they are the phosphate ester type compound containing a methacrylic ester group, and / or the fatty acid containing a methacrylic ester group.

Although the average particle diameter of the filler (C) of this invention is not specifically limited, 0.01-10 micrometers is preferable. By setting the average particle size to 0.01 μm or more, the film can be highly filled with the filler (C). As a result, the shrinkage resistance of the film with time is improved, and the average particle size is set to 10 μm or less. By doing so, the flexibility and tear propagation resistance of the film are improved. 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 means D50 (median diameter of particle diameter distribution) measured by a laser diffraction method.

Moreover, it is important that content of the filler (C) in the composition which comprises a film is 20-100 mass parts with respect to a total of 100 mass parts of resin (A) and resin (B). When it is less than 20 parts by mass, the film has insufficient shrinkage resistance with time, and when it exceeds 100 parts by mass, the flexibility, tear propagation resistance, and total light transmittance of the film are deteriorated. It is preferable that content of the filler (C) in the composition which comprises a film is 20-60 mass parts with respect to a total of 100 mass parts of resin (A) and resin (B), and 25-55 mass. More preferably, it is a part.
(Crystal nucleating agent)
The polylactic acid-based multifilm of the present invention may contain a crystal nucleating agent in order to improve the heat resistance and tear propagation resistance of the film.

  As the organic crystal nucleating agent, aliphatic amide compounds, melamine compounds, phenylphosphonic acid metal salts, benzenecarboxamide derivatives, aliphatic / aromatic carboxylic acid hydrazides, sorbitol compounds, amino acids, polypeptides, etc. are preferably used. be able to.

  As the inorganic crystal nucleating agent, carbon black, talc and the like can be preferably used.

As for content of the crystal nucleating agent in the composition which comprises a film, 0.1-10 mass parts is preferable with respect to a total of 100 mass parts of resin (A) and resin (B), and 0.5-5 mass parts Is more preferable.
(Tensile elongation)
The polylactic acid-based multifilm of the present invention preferably has a tensile elongation in the length direction and the width direction of 100% to 500%. When the tensile elongation is 100% or more, film tearing and defects (holes) are less likely to occur during film formation, and the film forming property is improved. Therefore, the tensile elongation is preferably 100% or more. If the tensile elongation is 130% or more, the stretchability as a multi-film is further improved. Therefore, the tensile elongation is more preferably 150% or more. The tensile elongation is more preferably 150% or more. When the tensile elongation is 500% or less, it is difficult for tarmi and wrinkles to occur during roll-to-roll travel and winding, and the roll winding shape and unwinding property are improved. Therefore, the tensile elongation is 500% or less. preferable.

As a method for setting the tensile elongation in the length direction and the width direction to 100% to 500%, the contents of the resin (A), the resin (B) and the filler (C) in the composition constituting the film are as follows. , A method for setting the above-described preferred ranges, a method for mixing the crystalline polylactic acid-based resin and the amorphous polylactic acid-based resin described above as the resin (A), and a method for setting the combination of the resin (B) described above to be preferable. And a method of setting the relationship between the type and mass ratio of the surface treatment agent of the filler (C) and the specific surface area of the filler to the preferred contents described above. More preferred is a method of combining a plurality of these methods, and still more preferred is a method of combining all of these methods.

(Tensile modulus)
The polylactic acid-based multifilm of the present invention preferably has a tensile modulus in the length direction and the width direction of 200 to 1,500 MPa. By setting the pressure to 200 MPa or more, tarmi and wrinkles are less likely to occur during traveling between rolls during film formation and during winding, and the roll winding form and unwinding property are improved. Moreover, the softness | flexibility sufficient as a multifilm can be provided by setting it as 1500 MPa. The tensile modulus is more preferably 200 to 1,000 MPa, and further preferably 250 to 900 MPa.

As a method for adjusting the tensile modulus in the length direction and the width direction to 200 to 1,200 MPa, the contents of the resin (A), the resin (B), and the filler (C) are described above. A method of making the preferred range, a method of mixing the crystalline polylactic acid-based resin and the amorphous polylactic acid-based resin described above as the resin (A), a method of making the combination of the resin (B) preferable as described above, a filler ( The method of making the relationship of the kind of a surface treating agent of C) and the mass ratio and the specific surface area of a filler into the preferable content mentioned above is mentioned. More preferred is a method of combining a plurality of these methods, and still more preferred is a method of combining all of these methods.
(Thickness)
The polylactic acid-based multifilm of the present invention preferably has a film thickness of 5 to 100 μm. By making the film thickness 5 μm or more, the stretchability as a multi-film becomes good, the stiffness when made into a film becomes strong, the handling property is excellent, and the roll winding shape and unwinding property are also good. Become. When the film thickness is 100 μm or less, the film becomes excellent in flexibility. In particular, in the inflation film forming method, bubbles do not become unstable due to their own weight. As for film thickness, 7-50 micrometers is more preferable, and 10-30 are still more preferable.
(Shrinkage factor)
The polylactic acid-based multifilm of the present invention is preferably excellent in shrinkage resistance with time, that is, the dimensional change of the film after film formation is preferably small. This is for maintaining the appearance of the roll wound with the film and the unwinding property of the film from the roll. Furthermore, when the film is spread as a multi-film, if the dimensional change is too large, the multi-film will float between the fences or cause tarmi, and as a result, it will be broken by stepping with your feet during work. There is a risk of being blown away by the wind. As a measure of the shrinkage resistance with time, the polylactic acid-based multifilm of the present invention has a shrinkage rate (heat shrinkage rate) of −2 to 2% in both the length direction and the width direction after storage at 65 ° C. for 30 minutes. Preferably there is. By setting it to 2% or less, it is possible to suppress deterioration of the winding shape due to shrinkage with time of the film after winding, so-called winding tightening. Furthermore, the occurrence of blocking due to excessively high winding hardness can be suppressed. Furthermore, it is possible to suppress lifting between the furrows when the multi-film is stretched. Moreover, by setting it as -2% or more, the deterioration of a winding form by the film after winding up loosening to a length direction with time can be suppressed. Here, when the shrinkage rate is less than 0 (negative value), it means that the film is stretched. The shrinkage rate is more preferably −1.5 to 1.5%.

As a method for adjusting the shrinkage in the length direction and the width direction to -2 to 2%, the resin (A), the resin (B), and the filler (C) in the composition constituting the film are used. The method of setting the content of each of the above-described preferred ranges, particularly the method of setting the content of the filler (C) in the preferred range, the crystalline polylactic acid-based resin and the amorphous polylactic acid-based as described above as the resin (A) The preferred content described above is the method of mixing the resin, the method of making the combination of the resin (B) preferred as described above, the type and mass ratio of the surface treatment agent of the filler (C) and the specific surface area of the filler. The method to make is mentioned. More preferred is a method of combining a plurality of these methods, and still more preferred is a method of combining all of these methods.

(Tear propagation resistance)
The polylactic acid-based multifilm of the present invention preferably has a tear propagation resistance in the length direction and the width direction of 10 N / mm or more. When the tear propagation resistance is 10 N / mm or more, tearing from the cut surface and the fixed planting hole is difficult to proceed when the film is spread as a multi-film in the field. Further, the tear propagation resistance in the length direction and the width direction is more preferably 20 N / mm or more, and further preferably 30 N / mm or more. Although there is no particular upper limit for the tear propagation resistance value, the polylactic acid-based multifilm of the present invention contains the specific amount of the resin (A), the resin (B), and the filler (C). The tear propagation resistance value is estimated to be about 500 N / mm.

Content of resin (A), resin (B), and filler (C) in the composition constituting the film in order to make the tear propagation resistance in the length direction and the width direction both 10 N / mm or more In which the content of the filler (C) is in a preferable range, and the crystalline polylactic acid resin and the amorphous polylactic acid resin described above as the resin (A) are mixed. A method for making the combination of the resin (B) preferable as described above, and a method for setting the relationship between the type and mass ratio of the surface treatment agent for the filler (C) and the specific surface area of the filler as described above. Is mentioned. More preferred is a method of combining a plurality of these methods, and still more preferred is a method of combining all of these methods.
(Total light transmittance)
The polylactic acid-based multifilm of the present invention preferably has a total light transmittance of 75% or more. When the total light transmittance is 75% or more, a sufficient effect of increasing the ground temperature can be obtained when the film is spread on a field as a multi-film. The total light transmittance is more preferably 80% or more. In addition, although the upper limit of the total light transmittance is theoretically 100%, the polylactic acid-based multifilm of the present invention contains the specific amount of the resin (A), the resin (B), and the filler (C). Therefore, it is estimated that the total light transmittance is about 95%.

In order to set the total light transmittance to 75% or more, the contents of the resin (A), the resin (B), and the filler (C) in the composition constituting the film are within the preferable ranges described above. Method, Method of Mixing Crystalline Polylactic Acid Resin and Amorphous Polylactic Acid Resin as described above as Resin (A), Method of Making Combination of Resin (B) Preferred as above, Surface of Filler (C) The method of making the relationship of the kind and mass ratio of a processing agent and the specific surface area of a filler into the preferable content mentioned above is mentioned. More preferred is a method of combining a plurality of these methods, and still more preferred is a method of combining all of these methods.
(Organic lubricant)
It is preferable that the composition which comprises the polylactic acid-type multifilm of this invention contains 0.1-5 mass% of organic lubricants in 100 mass% of the whole composition. In this case, blocking of the film after winding can be favorably suppressed. Furthermore, as will be described later, when producing the polylactic acid-based multifilm of the present invention, when the composition is once pelletized, dried, melt-kneaded again and extruded and formed into a film, blocking between the pellets is prevented. This is preferable in terms of handleability.

Examples of organic lubricants include liquid paraffins, natural paraffins, synthetic paraffins, aliphatic hydrocarbons such as polyethylene, stearic acid, lauric acid, hydroxystearic acid, fatty castors such as hard castor oil, stearic acid amide, oleic acid amide, Fatty acid amides such as erucic acid amide, lauric acid amide, ethylene bis stearic acid amide, ethylene bis oleic acid amide, ethylene bis lauric acid amide, fatty acid metal salts such as aluminum stearate, lead stearate, calcium stearate, magnesium stearate , Fatty acid (partial) esters of polyhydric alcohols such as glycerin fatty acid esters and rubitan fatty acid esters, long chain fatty acid esters such as long chain ester waxes such as butyl stearate and montan wax And the like. Among these, fatty acid amide organic lubricants that are easy to obtain an effect in a small amount due to moderate compatibility with polylactic acid are preferred. Among them, organic lubricants having a relatively high melting point such as ethylene bis stearic acid amide, ethylene bis oleic acid amide, and ethylene bis lauric acid amide are preferable from the viewpoint of expressing better blocking resistance.
(Additive)
The composition constituting the polylactic acid-based multifilm of the present invention may contain additives other than those described above as long as the effects of the present invention are not impaired. For example, known plasticizers, antioxidants, dispersants, UV stabilizers, anti-coloring agents, matting agents, antibacterial agents, deodorants, flame retardants, weathering agents, antistatic agents, antioxidants, ion exchange Agents, tackifiers, antifoaming agents, color pigments, dyes and the like.

  As the plasticizer, in addition to the resin-type plasticizer contained in the resin (B), phthalate esters such as diethyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, di-1-butyl adipate, di-adipate -N-octyl, di-n-butyl sebacate, aliphatic dibasic acid esters such as di-2-ethylhexyl azelate, phosphate esters such as diphenyl-2-ethylhexyl phosphate, diphenyloctyl phosphate, acetyl Hydroxypolycarboxylic acid esters such as tributyl citrate, tri-2-ethylhexyl citrate, tributyl acetylcitrate, fatty acid esters such as methyl acetylricinoleate and amyl stearate, glycerin triacetate, triethylene glycol dicaprylate Multivalent arco such as Glycol ester-based, epoxidized soybean oil, epoxidized linseed oil fatty acid butyl ester, and epoxy plasticizers such as epoxy stearic acid octyl. Moreover, it is also possible to use a mixture of two or more of these. In addition, from the viewpoint of the performance as a polylactic acid-based multifilm, particularly the flexibility of the film, tear propagation resistance, and bleed-out resistance, the plasticizer contained in the resin (B) is more preferable as the plasticizer. .

  Examples of the antioxidant include hindered phenols and hindered amines.

A dispersing agent is added in order to further improve the dispersibility in the resin composition of a filler (C), and a fatty acid etc. can be used.
(Carboxyl terminal)
The polylactic acid-based multifilm of the present invention needs to maintain the shape in the field for half a year to one year or more depending on the application. In that case, as the resin (A) (polylactic acid-based resin) or the resin (B) From the viewpoint of suppressing strength reduction due to hydrolysis of the polyester-based resin and imparting good durability, the carboxyl group terminal concentration of the film is preferably 30 equivalents / 10 ³ kg or less, more preferably 20 equivalents / It is 10 ³ kg or less, more preferably 10 equivalents / 10 ³ kg or less. When the carboxyl group terminal concentration of the film is 30 equivalents / 10 ³ kg or less, the carboxyl group terminal concentration that also serves as a hydrolysis autocatalyst is sufficiently low. There are many cases where this is possible.

Examples of a method for setting the carboxyl group terminal concentration of the film to 30 equivalents / 10 ³ kg or less include, for example, a catalyst or heat during synthesis of a resin (A) (polylactic acid resin) or a polyester resin as the resin (B). Control method by history, oligomer removal, etc., reduction of moisture content of resin used during film formation, reduction of extrusion temperature or retention time during film formation, reduction of thermal history, oligomer removal method, reaction type The method etc. which block the carboxyl group terminal using a compound are mentioned. Among these, a method using a reactive compound is preferable. That is, the polylactic acid-based multifilm of the present invention is preferably a film obtained using a composition obtained by reacting a reactive compound with the resin (A) and / or the resin (B).

  In the method of blocking the carboxyl group terminal using a reactive compound, it is preferable that at least a part of the carboxyl group terminal in the film is blocked. Examples of reactive compounds include condensation reactive compounds such as aliphatic alcohols and amide compounds, and addition reactive compounds such as carbodiimide compounds, epoxy compounds, and oxazoline compounds, but extra by-products are generated during the reaction. An addition reaction type compound is preferable in terms of difficulty, and among them, a carbodiimide compound and an epoxy compound are preferable from the viewpoint of reaction efficiency.

  The carbodiimide compound is a compound having at least one carbodiimide group represented by (—N═C═N—) in the molecule, and commercially available products include Nisshinbo's “Carbodilite” series, Rhein Chemie. The company's “Stabaxol” series and the like.

  Examples of the epoxy compound include glycidyl ether compounds, glycidyl ester compounds, glycidyl amine compounds, glycidyl imide compounds, glycidyl (meth) acrylate compounds, and alicyclic epoxy compounds. Commercially available products include BASF's “Joncry” series of glycidyl group-containing acrylic / styrene copolymers, “Reseda” series, “Alfon” series of glycidyl group-containing acrylic resins. Examples include the “Tepic” series of Nissan Chemical Co., Ltd., which are epoxy compounds with a triazine skeleton.

The compounding amount of the reactive compound in the polylactic acid-based multifilm of the present invention is preferably 0.01 to 10 parts by mass, and 0.05 to 5 with respect to 100 parts by mass in total of the resin (A) and the resin (B). Mass parts are more preferable, 0.1 to 3 parts by mass are further preferable, and 0.5 to 2 parts by mass are particularly preferable.
(Lactic acid oligomer component amount)
In the polylactic acid-based multifilm of the present invention, the amount of lactic acid oligomer component contained in the film is preferably 0.3% by mass or less. More preferably, it is 0.2 mass% or less, More preferably, it is 0.1 mass% or less. By controlling the amount of the lactic acid oligomer component contained in the film to 0.3% by mass or less, the deterioration of the handling property when the lactic acid oligomer component remaining in the film is precipitated as a powder or liquid, The progress of hydrolysis of the polylactic acid resin can be suppressed to prevent deterioration of the film over time, and furthermore, the odor peculiar to polylactic acid can be suppressed. The term “lactic acid oligomer component” as used herein refers to lactic acid, a linear oligomer of lactic acid, a cyclic oligomer of lactic acid, etc., which is quantitatively representative among lactic acid and lactic acid cyclic dimer (lactide). Lactide and DD-lactide, DL (meso) -lactide. A method for setting the amount of the lactic acid oligomer component to 0.3% by mass or less will be described later.
(Production method)
Next, the method for producing the polylactic acid-based multifilm of the present invention will be described in detail, but is not limited thereto.

  The polylactic acid resin which is the resin (A) in the present invention can be obtained, for example, by the following method. As a raw material, a lactic acid component of L-lactic acid or D-lactic acid is mainly used, and a hydroxycarboxylic acid other than the lactic acid component described above can be used in combination. Further, a cyclic ester intermediate of hydroxycarboxylic acid, for example, lactide, glycolide, etc. can be used as a raw material. Furthermore, dicarboxylic acids and glycols can also be used.

  The polylactic acid resin can be obtained by a method of directly dehydrating and condensing the raw materials or a method of ring-opening polymerization of the cyclic ester intermediate. For example, in the case of producing by direct dehydration condensation, lactic acid or lactic acid and hydroxycarboxylic acid are preferably subjected to azeotropic dehydration condensation in the presence of an organic solvent, particularly a phenyl ether solvent, and particularly preferably a solvent distilled by azeotropic distillation. A polymer having a high molecular weight can be obtained by polymerizing by a method in which water is removed from the solvent and the solvent is brought into a substantially anhydrous state and returned to the reaction system.

  It is also known that a high molecular weight polymer can be obtained by subjecting a cyclic ester intermediate such as lactide to ring-opening polymerization under reduced pressure using a catalyst such as tin octylate. At this time, a method for adjusting the conditions for removing moisture and low molecular weight compounds during heating and refluxing in an organic solvent, a method for suppressing the depolymerization reaction by deactivating the catalyst after completion of the polymerization reaction, and a method for heat-treating the produced polymer Can be used to obtain a polymer with a small amount of lactide.

  The composition constituting the polylactic acid multifilm of the present invention, that is, resin (A) (polylactic acid resin), resin (B) (thermoplastic resin other than polylactic acid resin), filler (C), or In obtaining a composition containing other components such as an organic lubricant, it is possible to produce a composition by uniformly mixing a solution in which each component is dissolved in a solvent and then removing the solvent. It is preferable to employ a melt-kneading method that produces a composition by melt-kneading each component, which is a practical production method that does not require steps such as dissolution of raw materials and solvent removal. The melt kneading method is not particularly limited, and a commonly used known mixer such as a kneader, roll mill, Banbury mixer, single-screw or twin-screw extruder can be used. Among these, from the viewpoint of dispersibility of the resin (A), the resin (B), and the filler (C), it is preferable to use a twin screw extruder.

  The temperature at the time of melt kneading is preferably in the range of 150 ° C. to 240 ° C., and more preferably in the range of 190 ° C. to 210 ° C. from the viewpoint of preventing the deterioration of the polylactic acid resin.

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

  In producing the polylactic acid-based multifilm of the present invention, for example, when the composition obtained by the above-described method is once pelletized, melt-kneaded again and extruded and formed into a film, the pellet is heated to 60 to 100 ° C. For example, it is preferable that the moisture content be 500 ppm or less, preferably 200 ppm or less by drying for 6 hours or more. Furthermore, it is preferable to reduce the amount of lactic acid oligomer components in the composition containing a polylactic acid-based resin or the like by vacuum drying under a high vacuum with a degree of vacuum of 10 Torr or less. By reducing the amount of water in the composition containing a polylactic acid-based resin or the like to 500 ppm or less and the amount of lactic acid oligomer component, hydrolysis during melt-kneading can be prevented, thereby preventing a decrease in molecular weight. It is also preferable because the melt viscosity can be adjusted to an appropriate level and the film forming process can be stabilized. Also, from the same point of view, when pelletizing or melt-extrusion / film formation once, a twin-screw extruder with a vacuum vent hole is used and melt extrusion is performed while removing volatiles such as moisture and low molecular weight substances. It is preferable to do.

  When producing the polylactic acid-based multifilm of the present invention by an inflation method, for example, the following method is used. Pellets of the composition prepared by the method as described above are melt-extruded in a twin-screw extruder with a vent hole and led to an annular die, extruded from the annular die and supplied with dry air into a balloon shape (bubble). And then air-cooled and solidified uniformly with an air ring, taken up at a predetermined take-up speed while being folded flat with a nip roll, and then cut off both ends or one end as necessary to wind up the desired poly A lactic acid-based multifilm can be obtained.

  Moreover, the cylinder temperature at the time of melt extrusion of the composition constituting the polylactic acid-based multifilm of the present invention is usually in the range of 150 to 240 ° C, and the temperature of the annular die is preferably 150 to 190 ° C, more preferably 150 to It is in the range of 180 ° C.

  The annular die is preferably a spiral type in terms of thickness accuracy and uniformity.

  After forming into a film, various surface treatments may be applied for the purpose of improving printability, laminate suitability, coating suitability, and the like. Examples of the surface treatment include corona discharge treatment, plasma treatment, flame treatment, acid treatment, etc., and any method can be used, but continuous treatment is possible, and equipment for existing film forming equipment is used. Corona discharge treatment can be exemplified as the most preferable because of its easy installation and simple processing.

  Since the polylactic acid-based multifilm of the present invention is excellent in bleed resistance and blocking resistance, it can be smoothly unwound without problems when the film is unwound from the wound film roll.

When the polylactic acid-based multifilm of the present invention is produced by an inflation method, it is important to adjust the blow ratio and the draw ratio within a preferable range in order to obtain a film having excellent physical properties as a multifilm. Here, the blow ratio is a ratio R _L / R _O of the final radius R _{L of the} bubble and the radius R _O of the annular die, and the draw ratio is the winding speed V _L of the molded film and melted from the die lip. The ratio V _L / V _O of the speed V _{O at which} the resin is discharged. A preferable range of the blow ratio is 1.2 to 4.0, more preferably 1.2 to 3.5, and still more preferably 1.2 to 3.0. A preferable range of the draw ratio is 2 to 80, more preferably 4 to 70, still more preferably 5 to 60, and particularly preferably 6 to 50.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited thereto.
[Measurement and evaluation method]
Measurements and evaluations shown in the examples were performed under the following conditions.
(1) Specific surface area S (m ² / g)
Using the filler (precursor of filler (C)) before being treated with the surface treatment agent, the measurement was performed by the Blane permeation method defined in JIS R5201 (1997).
(2) Mass ratio T (mass%) of the portion derived from the surface treatment agent
The filler (precursor of filler (C)) before being treated with the surface treatment agent is charged into a Henschel mixer, which is a container-fixed mixer, and heated while stirring at a rotational speed of 1500 rpm. When the internal temperature reached 90 ° C., the surface treatment agent was added while spraying so that the mass ratio of the portion derived from the surface treatment agent in the filler (C) was T (mass%). The mixture was then reacted for 10 minutes. In addition, the rotation speed of a rotary blade, the temperature in a can, and mixing time can be suitably changed with the kind of filler and surface treatment agent.
(3) Tensile modulus (MPa)
Tensile elastic modulus was measured using TENSILON UCT-100 manufactured by Orientec Co., Ltd. in an atmosphere at a room temperature of 23 ° C. and a relative humidity of 65%.

Specifically, a sample is cut out in a strip shape having a length of 150 mm and a width of 10 mm in the measurement direction, and according to the method defined in JIS K-7127 (1999) at an initial tensile chuck distance of 50 mm and a tensile speed of 200 mm / min. The measurement was performed 10 times for each of the length direction and the width direction, and the average value was taken as the tensile elastic modulus in the length direction and the width direction.
(4) Tensile elongation Tensile elongation was measured using TENSILON UCT-100 manufactured by Orientec Corp. in an atmosphere at room temperature of 23 ° C and relative humidity of 65%.

Specifically, a sample is cut out in a strip shape having a length of 150 mm and a width of 10 mm in the measurement direction, and according to the method defined in JIS K-7127 (1999) at an initial tensile chuck distance of 50 mm and a tensile speed of 200 mm / min. The measurement was performed 10 times for each of the length direction and the width direction, and the average value was taken as the tensile elongation in the length direction and the width direction, respectively.
(5) Tear Propagation Resistance Using a tear propagation resistance meter (Elemendorf) manufactured by Toyo Seiki Seisakusho, the tear propagation resistance was measured according to the method defined in JIS K 7128-2 (1998). The sample size was 63 mm in the tearing direction × 76 mm in the vertical direction in the tearing direction. A notch of 20 mm was made in the tearing direction, and the indicated value when the remaining 43 mm was torn was read. The measurement was performed 5 times, and the average value was calculated. This was calculated for each of the length direction and width direction of the film.
(6) Shrinkage rate A sample was cut into a strip shape having a length of 150 mm and a width of 10 mm in the measurement direction, and a marked line between 100 mm was inserted in the length direction. This sample was treated for 30 minutes in a dry heat oven with the interior held at 65 ° C., then the dimension between the marked lines was measured, and the thermal shrinkage was calculated according to the following formula. The measurement was performed 5 times per level, and the heat shrinkage in the length direction was determined from the average value of the 5 measurements.
Shrinkage rate (%) = {(dimension before shrinkage) − (dimension after shrinkage)} / (dimension before shrinkage) × 100
The thermal contraction rate in the width direction was determined by the same method.
(7) Total light transmittance The total light transmittance value was measured using a haze meter NDH-5000 type (manufactured by Nippon Denshoku Industries Co., Ltd.). The measurement was performed 5 times per level, and the total light transmittance was determined from the average value of the 5 measurements.
[Resin (A)]
(A1)
Polylactic acid-based resin (mass average molecular weight = 200,000, D-form content = 1.4 mol%, melting point = 166 ° C.), which was previously dried in a vacuum at a temperature of 100 ° C. for 5 hours using a vacuum dryer did.
(A2)
Use a polylactic acid resin (mass average molecular weight = 200,000, D-form content = 5.0 mol%, melting point = 150 ° C.) previously dried in a vacuum at a temperature of 100 ° C. for 5 hours using a vacuum dryer. did.
(A3)
A polylactic acid resin (mass average molecular weight = 200,000, D-form content = 12.0 mol%, melting point = none) was previously vacuum-dried at a temperature of 50 ° C. for 7 hours using a vacuum dryer. .

  In addition, said mass mean molecular weight measured by Japan Warters Co., Ltd. product Warters2690, polymethylmethacrylate as a standard, column temperature of 40 degreeC, and the chloroform solvent.

The above melting point was determined by heating a polylactic acid resin in a hot air oven at 100 ° C. for 24 hours, using a differential scanning calorimeter RDC220 manufactured by Seiko Instruments Inc., and setting 5 mg of a sample in an aluminum tray. It was determined as the peak temperature of the crystal melting peak when the temperature was raised from 250C to 250C at a heating rate of 20C / min.
[Resin (B)]
(B1)
A polybutylene adipate terephthalate resin (manufactured by BASF, trade name “Ecoflex” F Blend C1200) was previously vacuum-dried at a temperature of 80 ° C. for 7 hours using a vacuum dryer.
(B2)
A polybutylene succinate resin (trade name “GSPla” AZ91T, manufactured by Mitsubishi Chemical Corporation) was previously dried in a vacuum at a temperature of 80 ° C. for 7 hours using a vacuum dryer.
(B3)
A polybutylene succinate adipate resin (trade name “Bionore” # 3001 manufactured by Showa Polymer Co., Ltd.) was previously dried in a vacuum at a temperature of 80 ° C. for 7 hours using a vacuum dryer.
(B4)
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 are mixed and polymerized in a reaction vessel equipped with a stirrer at 160 ° C. for 3 hours in a nitrogen atmosphere. As a result, a block copolymer plasticizer B4 having a polylactic acid segment having a number average molecular weight of 2,500 at both ends of polyethylene glycol having a number average molecular weight of 8,000 was obtained. The block copolymer plasticizer B4 was previously vacuum-dried at a temperature of 80 ° C. for 7 hours using a vacuum dryer.
[Plasticizer (P)]
The plasticizer (P) is a plasticizer that is not resin-based.
(P1)
Tributyl acetyl citrate, manufactured by Pfizer, trade name “Citroflex A-4”)
[Filler (C)]
(C1)
Calcium carbonate (made by Ajinomoto Fine Techno Co., Ltd., trade name “Top Flow H200”, average particle size: 1.7 μm, surface treatment agent: phosphate ester compound (containing a methacrylate ester group at the end), specific surface area S = 2.0 m ² / g, mass ratio of the portion derived from the surface treatment agent T = 1.8 mass%, T / S = 0.90)
(C2)
Calcium carbonate (trade name “E # 2010” manufactured by Sankyo Seimitsu Co., Ltd., average particle size: 1.8 μm, surface treatment agent: stearic acid, specific surface area S = 2.0 m ² / g, derived from surface treatment agent Part mass ratio T = 1.0 mass%, T / S = 0.50)
(C3)
Calcium carbonate (made by Ajinomoto Fine Techno Co., Ltd., trade name “Top Flow H100”, average particle size: 3.6 μm, surface treatment agent: phosphate ester compound (containing a methacrylic ester group at the terminal), specific surface area S = 1.0 m ² / g, the mass ratio of the part derived from the surface treatment agent T = 0.7 mass%, T / S = 0.70)
(C4)
Calcium carbonate (average particle size: 1.7 μm, surface treatment agent: phosphate ester compound (including methacrylic ester group at the terminal), specific surface area S = 2.0 m ² / g, part derived from the surface treatment agent (Mass ratio T = 0.7 mass%, T / S = 0.35)
(C5)
Calcium carbonate (average particle size: 3.6 μm, surface treatment agent: phosphate ester compound (including methacrylic ester group at the terminal), specific surface area S = 1.0 m ² / g, part derived from the surface treatment agent (Mass ratio T = 0.4 mass%, T / S = 0.40)
(C6)
Calcium carbonate (average particle size: 1.7 μm, surface treatment agent: phosphate ester compound (including methacrylic ester group at the terminal), specific surface area S = 2.0 m ² / g, part derived from the surface treatment agent (Mass ratio T = 0.5 mass%, T / S = 0.25)
[Filler (D)]
The filler (D) is a precursor of the filler (C) and is a compound before being treated with the surface treatment agent.
(D1)
Calcium carbonate (Sankyo Seimitsu Co., Ltd., trade name “# 2000”, average particle size: 1.8 μm, treatment with surface treatment agent: none)
[Production of polylactic acid-based multifilm]
Example 1
15 parts by mass of polylactic acid resin (A1), 35 parts by mass of polylactic acid resin (A3), 30 parts by mass of polybutylene adipate / terephthalate resin (B1), 20 parts by mass of block copolymer plasticizer (B4), filler (C1 ) 30 parts by mass of the mixture was subjected to a bi-directional extruder with a cylinder diameter of 200 ° C. and a screw diameter of 30 mm, melt-kneaded, homogenized and then pelletized to obtain a composition.

  The pellet of this composition was vacuum-dried at a temperature of 80 ° C. for 7 hours using a vacuum dryer.

The dried composition pellets were supplied to a co-directional extruder with a cylinder temperature of 170 ° C. and a screw diameter of 20 mm, and a blow ratio of 2.0 from a spiral annular die having a diameter of 50 mm, a lip clearance of 1.5 mm, and a temperature of 160 ° C. The film was extruded upward in a bubble shape, cooled by air with a cooling ring, taken up while being folded with a nip roll above the die, cut at both ends with an edge cutter, and cut into two sheets to obtain a film having a final thickness of 18 μm. At this time, the draw ratio was 42. Table 1 shows the physical properties of the obtained film.
(Examples 2-18, Comparative Examples 1-5)
A film was obtained in the same manner as in Example 1 except that the composition of the film was changed as shown in the table. The physical properties of the obtained film are shown in Tables 1 and 2.

  In the table, “mass%” of the resin (A) and the resin (B) is a value (mass%) at a total of 100 mass% of the resin (A) and the resin (B). Further, the “part by mass” of the filler (C) is a value (part by mass) when the total of the resin (A) and the resin (B) is 100 parts by mass. Further, “MD” and “TD” in the table are the length direction and the width direction, respectively.

  According to the present invention, the film has excellent flexibility, heat resistance, bleed-out resistance, durability, and excellent shrinkage with time, tear propagation resistance, and total light transmittance while containing a large amount of filler. Is obtained. The film of the present invention is suitable as a polylactic acid-based multifilm.

Claims (10)

The resin (A) is a polylactic acid resin, the resin (B) is a thermoplastic resin other than the polylactic acid resin, and the filler (C) is a film comprising a composition containing a compound treated with a surface treatment agent,
In a total of 100% by mass of the resin (A) and the resin (B), 30 to 70% by mass of the resin (A) and 30 to 70% by mass of the resin (B) are contained, and the resin (A) and the resin (B) A polylactic acid-based multifilm comprising a composition containing 20 to 100 parts by mass of a filler (C) with respect to 100 parts by mass in total.   The polylactic acid-based multifilm according to claim 1, wherein the polylactic acid-based resin includes a crystalline polylactic acid-based resin and an amorphous polylactic acid-based resin.   It consists of a composition which contains a filler (C) 20-60 mass parts with respect to a total of 100 mass parts of resin (A) and resin (B), The poly of Claim 1 or 2 characterized by the above-mentioned. Lactic acid type multi film.   The polylactic acid-based multi-component according to any one of claims 1 to 3, wherein the shrinkage rate after storage at 65 ° C for 30 minutes is from -2% to 2% in both the length direction and the width direction. the film.   The polylactic acid-based multifilm according to any one of claims 1 to 4, wherein tear propagation resistance in the length direction and width direction is 10 N / mm or more.   The polylactic acid-based multifilm according to any one of claims 1 to 5, wherein the total light transmittance is 75% or more.   The polylactic acid-based multifilm according to any one of claims 1 to 6, wherein the surface treatment agent is a phosphate ester compound and / or a fatty acid.   The polylactic acid-based multifilm according to any one of claims 1 to 7, wherein the surface treatment agent contains a methacrylic acid ester group.   The resin (B) is at least one resin selected from the group consisting of a block copolymer having a polyether-based segment and a polylactic acid segment, and a block copolymer having a polyester-based segment and a polylactic acid segment; and The polylactic acid-based multifilm according to claim 1, comprising at least one resin selected from the group consisting of an aliphatic polyester-based resin and an aliphatic aromatic polyester-based resin.   For the resin (B), the total mass ratio of a resin selected from the group consisting of an aliphatic polyester resin and an aliphatic aromatic polyester resin is a block copolymer having a polyether segment and a polylactic acid segment, and The polylactic acid-based multifilm according to claim 9, wherein the polylactic acid-based multifilm is more than a total mass ratio of a resin selected from the group consisting of a block copolymer having a polyester-based segment and a polylactic acid segment.