JPWO2010005043A1 - Polylactic acid resin film - Google Patents

Abstract

The present invention is excellent in heat sealability, impact resistance and transparency, particularly excellent for packaging materials, and also suitable for the inflation method, which is a relatively inexpensive facility, and is an economical polylactic acid resin film Is intended to provide. Polylactic acid resin (A) 65 mass% or more and 95 mass% or less, 190 degreeC, the melt mass flow rate under 2.16kg load: MFR (g / 10min) is 3 (g / 10min) or more, 9 (g / 10 minutes) or less, and having at least one heat-sealing layer made of a composition containing 5% by mass or more and 35% by mass or less of aliphatic polyester and / or aliphatic aromatic polyester (B) other than (A), Heat seal strength between heat seal layers: A polylactic acid resin film, wherein Hs is 7 (N / 15 mm) or more.

Description

  The present invention relates to a polylactic acid-based resin film excellent in heat sealability, impact resistance, and transparency, particularly excellent for packaging materials, and suitable for the inflation method, which is a relatively inexpensive facility, and excellent in economic efficiency. .

  In recent years, global warming due to an increase in the concentration of carbon dioxide in the atmosphere has become a global problem, and various industrial fields are actively developing technologies to reduce carbon dioxide emissions into the atmosphere. . In the field of plastic products, conventionally, plastics produced from general-purpose petroleum-derived raw materials have been incinerated after use and released into the atmosphere as carbon dioxide gas. Attention is focused on plant-derived plastics derived from gas. In particular, research and development for the practical use of polylactic acid, which is excellent in transparency and relatively advantageous in terms of cost, is thriving.

  Typical examples of plastics produced from general-purpose petroleum-derived raw materials include polyolefins such as polyethylene. For example, polyethylene is usually formed into a bag shape by an inflation method, processed into a bag shape by a process such as heat sealing and cutting with a bag making machine, and then used in a large amount for various packaging films. In recent years, many attempts have been made to apply polylactic acid to such heat-sealable films.

  For example, as represented by Patent Document 1, a laminated structure consisting of at least two layers of a base material layer and a sealing layer, and heat sealability is imparted based on the difference in melting point or softening point between the base material layer and the sealing layer. Many attempts have been made.

  Patent Document 2 discloses a film containing a polylactic acid polymer and another aliphatic polyester in a certain ratio.

  Further, Patent Document 3 discloses a film that defines a unique phase transition index in a product mainly composed of a polylactic acid polymer.

  Patent Document 4 discloses a film made of a mixture of a polylactic acid resin and a biodegradable polyester other than the polylactic acid resin having a glass transition temperature Tg of 10 ° C. or lower.

JP-A-8-323946 JP-A-11-222528 JP 2003-128797 A JP 2003-292642 A

  However, each of the attempts to impart heat sealability described in Patent Document 1 described above requires two or more extruders, and most of them are films using a T-die biaxial stretching method, which requires equipment costs and installation area. A relatively new low-volume, multi-product type polymer such as polylactic acid that is difficult to reuse by trimming clip parts at both ends after transverse stretching with a normal tenter, but recovering the trimming loss. This is a less economical method.

  In addition, the film described in Patent Document 2 has a problem that transparency is insufficient for packaging materials because of the relatively high content of other aliphatic polyesters.

  Furthermore, the film described in Patent Document 3 is basically a technique for a stretched film although it is a single film, and has a problem that it is still insufficient in practice as heat sealability.

  And although the film described in patent document 4 was re-tryed according to the technique of an Example description, there existed a problem that heat seal intensity | strength was not enough.

  Furthermore, in any of the above-mentioned patent documents, it is very important for imparting heat sealability with a uniform and sufficient strength for practical use. Not touched.

  As described above, heat-sealability, impact resistance, transparency, particularly for packaging materials, and also a polylactic acid-based resin film with excellent economics that can be manufactured with relatively inexpensive equipment, It has not yet been achieved.

  In view of the background of such prior art, the present invention is excellent in heat sealability, impact resistance and transparency, particularly excellent for packaging materials, and more suitable for the inflation method which is a relatively inexpensive facility. It is intended to provide a polylactic acid-based resin film excellent in the quality.

In order to solve the above problems, the present invention employs the following means.
1) The polylactic acid resin (A) contains 65% by mass or more and 95% by mass or less, melt mass flow rate under 190 ° C. and 2.16 kg load: MFR (g / 10 minutes) is 3 (g / 10 minutes) or more, At least one heat seal layer comprising a composition containing 5% by mass or more and 35% by mass or less of an aliphatic polyester and / or an aliphatic aromatic polyester (B) other than (A) that is 9 (g / 10 minutes) or less. And a heat-sealing strength between the heat-sealing layers: Hs is 7 (N / 15 mm) or more.
2) The polylactic acid resin film as described in 1) above, wherein the aliphatic polyester and / or the aliphatic aromatic polyester (B) is a polybutylene succinate resin.
3) The polylactic acid-based resin film as described in 1) or 2) above, which has a single-layer structure consisting of only a heat seal layer.
4) Film haze: The polylactic acid resin film according to any one of 1) to 3) above, wherein Ha (%) is 1% or more and 10% or less.
5) Coefficient of dynamic friction between heat seal layers of the polylactic acid-based resin film: μd is 0.5 or less, The polylactic acid-based resin film according to any one of 1) to 4) above.
6) The end resistance is 30 (N / 20 mm) or more and 90 (N / 20 mm) or less in both the winding length direction (MD direction) and the width direction (direction orthogonal to the winding length direction: TD direction). The polylactic acid resin film as described in any one of 1) to 5) above.
7) The polylactic acid resin film as described in any one of 1) to 6) above, wherein the composition contains particles (C) having an average particle diameter of 3 μm or more and 6 μm or less.
8) A bag using the polylactic acid resin film according to any one of 1) to 7).

  According to the present invention, a polylactic acid-based resin excellent in heat sealability, impact resistance, and transparency, particularly excellent in packaging materials, and suitable for the inflation method, which is a relatively inexpensive facility, and excellent in economic efficiency. A film is provided. Since the polylactic acid-based resin film of the present invention is excellent in heat sealability, impact resistance, and transparency, bags for various industrial products, bags for miscellaneous goods such as CD cases, bags for foodstuffs such as vegetables and fruits, and tubes It can be preferably used for various packaging applications such as bags, pillow bags, and banding tapes.

  The present invention has the above-mentioned problems, that is, excellent heat sealing properties, impact resistance, and transparency, particularly excellent for packaging materials, and also has excellent economical efficiency that can be manufactured with relatively inexpensive equipment. As a result of intensive studies on the film, it was the first successful solution to this problem.

  That is, in the polylactic acid resin film of the present invention, the composition contains 65% by mass to 95% by mass of the polylactic acid resin (A), and the composition further has a melt mass flow rate at 190 ° C. under a load of 2.16 kg. : MFR (g / 10 min) of 3 (g / 10 min) or more and 9 (g / 10 min) or less of aliphatic polyester and / or aliphatic aromatic polyester (B) other than (A) 5 It is characterized by having at least one heat seal layer comprising the composition and containing at least one mass% and not more than 35 mass%, and having a heat seal strength between the heat seal layers: Hs of 7 (N / 15 mm) or more.

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

  As the polylactic acid resin (A) used for the polylactic acid resin film of the present invention, those containing L-lactic acid and / or D-lactic acid as main components are preferably used. The main component means that the component derived from lactic acid is 70% by mass or more and 100% by mass or less in 100% by mass of the total components of the resin, and homopolylactic acid substantially consisting of L-lactic acid and / or D-lactic acid is preferable. Used.

  The polylactic acid resin (A) used in the present invention preferably has crystallinity. The polylactic acid-based resin (A) has crystallinity when the polylactic acid-based resin is sufficiently crystallized under heating and then subjected to differential scanning calorimetry (DSC) measurement in an appropriate temperature range. It means that the heat of crystal melting derived from the polylactic acid component is observed. When the polylactic acid resin (A) used for this invention has crystallinity, it is suitable at the point which can provide heat resistance with respect to a polylactic acid-type resin film. In general, homopolylactic acid has higher melting point and crystallinity as the optical purity is higher. The melting point and crystallinity of polylactic acid are affected by the molecular weight and the catalyst used during polymerization, but normally, homopolylactic acid having an optical purity of 98% or more has a melting point of about 170 ° C. and a relatively high crystallinity. Further, as the optical purity is lowered, the melting point and crystallinity are lowered. For example, homopolylactic acid having an optical purity of 88% has a melting point of about 145 ° C., and homopolylactic acid having an optical purity of 75% has a melting point of about 120 ° C. It is. Homopolylactic acid with an optical purity lower than 70% does not show a clear melting point and is amorphous.

  The polylactic acid-based resin (A) used in the present invention may be mixed with crystalline homopolylactic acid and amorphous homopolylactic acid for the purpose of imparting or improving necessary functions depending on the application used as a film. Is possible. In this case, the proportion of amorphous homopolylactic acid may be determined within a range that does not impair the effects of the present invention. In addition, when it is desired to impart relatively high heat resistance when a polylactic acid resin film is used, at least one of the polylactic acid resins (A) used may contain polylactic acid having an optical purity of 95% or more. preferable.

  The mass average molecular weight of the polylactic acid resin (A) used in the present invention is usually at least 50,000, preferably 80,000 to 400,000, and more preferably 100,000 to 300,000. Here, the mass average molecular weight is a molecular weight calculated by a polymethyl methacrylate conversion method after measurement with a chloroform solvent by gel permeation chromatography (GPC).

  By setting the mass average molecular weight of the polylactic acid-based resin (A) to at least 50,000, when the composition containing the polylactic acid-based resin (A) is processed into a film, the mechanical properties are excellent. can do.

  In addition, the polylactic acid resin (A) used in the present invention may be a copolymerized polylactic acid obtained by copolymerizing other monomer components having ester forming ability in addition to L-lactic acid and D-lactic acid. Examples of copolymerizable monomer components include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid, and other hydroxycarboxylic acids, as well as ethylene glycol, propylene glycol, and butane. Compounds containing a plurality of hydroxyl groups in the molecule such as diol, neopentyl glycol, polyethylene glycol, glycerin, pentaerythritol or their derivatives, succinic acid, adipic acid, sebacic acid, fumaric acid, terephthalic acid, isophthalic acid, 2 , 6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium sulfoisophthalic acid and the like, or compounds containing a plurality of carboxylic acid groups in the molecule. In addition, it is preferable to select the component which has biodegradability among the above-mentioned copolymerization components according to a use. Further, even when a copolymerized polylactic acid is used as the polylactic acid-based resin (A), a copolymerized polylactic acid in which the component derived from lactic acid is 70% by mass or more in 100% by mass of all the components of the resin as described above is preferably used It is done.

  The production method of the polylactic acid resin (A) will be described in detail later, 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.

  The polylactic acid resin film of the present invention has at least one heat seal layer made of a composition containing 65% by mass or more and 95% by mass or less of the polylactic acid resin (A) described above. When the composition constituting the heat seal layer contains less than 65% by mass of the polylactic acid resin (A), it is insufficient as a practical technology for plant-derived materials, which is the object of the present invention. Moreover, when the ratio of the polylactic acid-type resin (A) of the composition which comprises this heat seal layer is more than 95 mass%, when it is set as a polylactic acid-type resin film, sufficient heat-sealability is not acquired.

  Moreover, the polylactic acid-type resin film of this invention contains 5 mass% or more and 35 mass% or less of aliphatic polyesters and / or aliphatic aromatic polyesters (B) other than polylactic acid other than polylactic acid-type resin (A). It has at least one heat seal layer made of the composition. When the composition constituting the heat seal layer contains less than 5% by mass of an aliphatic polyester and / or an aliphatic aromatic polyester (B) other than the polylactic acid resin (A), the heat seal layer is When the film is included, sufficient heat sealability cannot be obtained. Moreover, when the composition which comprises this heat seal layer contains aliphatic polyester and / or aliphatic aromatic polyester (B) other than polylactic acid-type resin (A) exceeding 35 mass%, (A) and ( Similarly, sufficient heat sealability cannot be obtained mainly due to the interfacial peeling of B). From the same viewpoint, the content of (B) is preferably 10% by mass or more and 20% by mass or less of the composition constituting the heat seal layer. In addition, impact resistance is also provided to the polylactic acid-type resin film of this invention which has at least 1 layer of a heat seal layer and this heat seal layer by containing (B).

  Examples of aliphatic polyesters and / or aliphatic aromatic polyesters (B) other than polylactic acid include polyglycolic acid, poly (3-hydroxybutyrate), and poly (3-hydroxybutyrate / 3-hydroxyvalerate). , Polycaprolactone, or an aliphatic polyester composed of an aliphatic diol such as ethylene glycol or 1,4-butanediol and an aliphatic dicarboxylic acid such as succinic acid or adipic acid, or poly (butylene succinate / terephthalate), poly ( A copolymer of an aliphatic polyester such as butylene adipate and terephthalate) and an aromatic polyester. Among them, aliphatic polyesters and / or aliphatic aromatic polyesters (B) other than polylactic acid are polybutylene succinates and polybutylene succinates and adipates. Polybutylene succinate-based resins such as polybutylene succinate and adipate are particularly preferably used.

  Melt mass flow rate of aliphatic polyester and / or aliphatic aromatic polyester (B) other than polylactic acid resin (A) under a load of 190 ° C. and 2.16 kg: MFR (g / 10 minutes) (JIS-K-7210) : 1999) is 3 (g / 10 min) or more and 9 (g / 10 min) or less. When the above MFR is less than 3 (g / 10 minutes) and (B) has a higher viscosity, the dispersibility of (B) in (A) is reduced, and (A) and (B) are contained in specific amounts. Good heat-sealability cannot be imparted to the heat-seal layer comprising the composition. In addition, when the MFR of (B) is more than 9 (g / 10 minutes) and (B) has a lower viscosity, the composition constituting the heat seal layer of the polylactic acid resin film of the present invention When the film is formed by the inflation method, the bubbles become unstable.

  Melt mass flow rate of aliphatic polyester and / or aliphatic aromatic polyester (B) at 190 ° C. under a load of 2.16 kg: MFR (g / 10 minutes) (JIS-K-7210: 1999) is 3 (g / 10 minutes) to 9 (g / 10 minutes) or less, for example, adjustment of molecular weight and molecular weight distribution of aliphatic polyester and / or aliphatic aromatic polyester (B), addition by copolymerization of branched chain It is possible by means such as selection of monomers constituting the main chain.

  As described above, the polylactic acid-based resin film of the present invention comprises a polylactic acid-based resin (A) at 65 mass% to 95 mass%, a melt mass flow rate under a load of 190 ° C. and 2.16 kg: MFR (g / 10 minutes) ) Is 3 (g / 10 minutes) or more and 9 (g / 10 minutes) or less, and the aliphatic polyester and / or aliphatic aromatic polyester (B) other than (A) is 5% by mass or more and 35% by mass or less. The heat seal layer is composed of at least one layer composed of a composition containing the same, but the inside may have a single-layer structure having the same composition as the heat seal layer (that is, a polylactic acid resin film composed of only the heat seal layer). A laminated structure including a plurality of layers having a layer made of a composition different from the layer may be used. In order to provide the object of the present invention, particularly excellent properties for a packaging material, and at the same time to provide high economic efficiency, it is more preferable to use a single-layer structure having only a heat seal layer. In addition, when setting it as a laminated structure, the heat seal layer of this invention which consists of a composition containing polylactic acid-type resin (A) and aliphatic polyester and / or aliphatic aromatic polyester (B) is at least 1 layer of outermost layer. It is important that

  In addition, a heat seal layer means the layer which can be bonded together with another layer by making it contact with another layer in the state which provided the heat | fever to this layer. The heat sealing layer in the polylactic acid resin film of the present invention is not particularly limited as long as it can be bonded to another layer by applying heat, but the heat sealing strength between the heat sealing layers: 7 (N / 15 mm) That is important. In addition, the heat seal strength said here is the value measured by the method of an Example description. When the heat seal strength is less than 7 (N / 15 mm), the seal strength is practically insufficient such that the heat seal portion may be peeled off during use without breaking the film. That is, for example, when at least one heat seal layer of the polylactic acid-based resin film of the present invention is bonded to form a bag, there arises a problem that the heat seal portion is peeled off during use as a bag. In addition, about the heat seal layer of the polylactic acid-type resin film of this invention, although there is no upper limit in heat seal strength and it is so preferable that a value is large, in the case of polylactic acid-type resin, the upper limit of heat seal strength is usually 30 (N / 15mm). Therefore, the practically achievable upper limit of the heat seal strength of the heat seal layer used in the film of the present invention is considered to be about 30 (N / 15 mm), and the upper limit is 13 (N / 15 mm). ) Is sufficient from the viewpoint of use as a bag.

  In addition, in order to make the heat seal strength of the heat seal layers of the polylactic acid resin film of the present invention: Hs 7 or more (N / 15 mm), the polylactic acid in the composition constituting the heat seal layer as described above Content of the resin-based resin (A) is 65% by mass to 95% by mass, and the content of the aliphatic polyester and / or the aliphatic aromatic polyester (B) in the composition constituting the heat seal layer Of an aliphatic polyester and / or aliphatic aromatic polyester (B) at 190 ° C. under a load of 2.16 kg: MFR (g / 10 minutes) ) (JIS-K-7210: 1999) in an embodiment wherein 3 (g / 10 minutes) to 9 (g / 10 minutes) or less, aliphatic polyester Examples thereof include a mode in which a polybutylene succinate resin is used as the ruthenium and / or aliphatic aromatic polyester (B).

  The polylactic acid resin film of the present invention preferably has a haze of 1% to 10%, more preferably 8% or less, and even more preferably 5% or less. When the haze is 10% or less, the contents can be easily confirmed when molded into various packaging applications such as bags for foods such as vegetables and fruits, bags for various industrial products, etc. It is often preferable due to its high design properties. In addition, from the general characteristic of polylactic acid, it is difficult to make the haze of the polylactic acid-based resin film less than 1%, so the lower limit is about 1%. A lower limit of about 2% is sufficient.

  The polylactic acid resin film of the present invention preferably has a coefficient of dynamic friction (μd) between heat seal layers of the polylactic acid resin film of 0.5 or less. In this case, it is preferable in that it can be easily wound up without wrinkles or tarmi due to an appropriate sliding property. The dynamic friction coefficient (μd) between the heat seal layers of the polylactic acid resin film is more preferably 0.45 or less. In general, the coefficient of dynamic friction in the case of a polylactic acid-based resin film is difficult to be less than 0.1, so the lower limit is about 0.1 and the lower limit is about 0.2.

  The polylactic acid-based resin film of the present invention has an end tear resistance of 30 (N / 20 mm) or more in both the winding length direction (MD direction) and the width direction (direction orthogonal to the winding length direction: TD direction). (N / 20 mm) or less is preferable. Note that the end-row resistance value generally has a positive correlation with the impact resistance. When the end-row resistance value is high, the end-row resistance value often has high impact resistance. If the end tear resistance is 30 (N / 20 mm) or more in both directions, it can be said that mechanical properties and impact resistance have no particular problems in general use in various packaging applications, which is a preferred application of the present invention. Further, if the end resistance is 90 (N / 20 mm) or less in both directions, it is possible to manufacture with an inflation type film forming machine which is a relatively inexpensive facility, which is economically advantageous. From the same viewpoint, the polylactic acid-based resin film of the present invention has an end tear resistance of 35 (N / 20 mm) or more and 75 (N / 20 mm) or less in both directions, more preferably 40 (N / 20 mm) or more and 65 (N / 20 mm) or less is more preferable. In addition, both the winding length direction (MD direction) and the width direction (direction orthogonal to the winding length direction: TD direction) of the polylactic acid-based resin film are directions in the film plane.

  The end tear resistance of the polylactic acid-based resin film of the present invention is 30 (N / 20 mm) or more in the winding length direction (MD direction) and the width direction (direction perpendicular to the winding length direction: TD direction), 90 (N / 20 mm) or less, it is important to form the film while adjusting the orientation of the film. The film is produced by an inflation film-forming method, or formed by an unstretched film-forming method such as a T-die casting method. Examples thereof include a method of forming a film while suppressing orientation in a biaxially stretched film forming method such as a T-die casting / biaxial stretching method or a tubular method.

  In the composition which comprises the heat seal layer of the polylactic acid-type resin film of this invention, you may contain components other than having mentioned above in the range which does not impair the effect of this invention. For example, known antioxidants, UV stabilizers, anti-coloring agents, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, antioxidants, ion exchange agents, plasticizers, crystal nucleating agents, Inorganic particles, organic particles, and organic compounds may be added as necessary as coloring pigments or lubricants.

  The composition which comprises the heat seal layer of the polylactic acid-type resin film of this invention may add an organic lubricant in the range which does not impair the effect of this invention. When the organic lubricant is added, the addition amount is usually 0.1% by mass or more and 5% by mass or less. In this case, blocking after winding can be favorably suppressed. In addition, problems such as a decrease in melt viscosity and deterioration of workability due to excessive addition of an organic lubricant, or poor appearance such as bleed out and haze up when formed into a film are less likely to occur.

  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, stearic acid amide and ethylene bis-stearic acid amide, which are easy to obtain an effect in a small amount due to appropriate compatibility with polylactic acid, are preferable.

Examples of the antioxidant include hindered phenols and hindered amines. Color pigments include inorganic pigments such as carbon black, titanium oxide, zinc oxide, iron oxide, cyanine, styrene, phthalocyanine, anthraquinone, perinone, isoindolinone, quinophthalone, and quinocridone. Organic pigments such as thioindigo can be used.

  In addition, when particles (C) are contained in the composition constituting the heat seal layer of the polylactic acid resin film of the present invention for the purpose of improving the slipperiness and blocking resistance of the processed product, for example, inorganic The particles include silicon oxide such as silica, various carbonates such as calcium carbonate, magnesium carbonate and barium carbonate, various sulfates such as calcium sulfate and barium sulfate, various composite oxides such as kaolin and talc, lithium phosphate and calcium phosphate. Fine particles comprising various phosphates such as magnesium phosphate, various oxides such as aluminum oxide, titanium oxide and zirconium oxide, and various salts such as lithium fluoride can be used.

  Moreover, when using organic particles as particles (C) to be included in the composition constituting the heat seal layer of the polylactic acid-based resin film of the present invention, calcium oxalate, calcium, barium, zinc, manganese, magnesium, etc. Fine particles made of terephthalate are used. Examples of the crosslinked polymer particles include fine particles made of a vinyl monomer such as divinylbenzene, styrene, acrylic acid or methacrylic acid, or a copolymer. In addition, organic fine particles such as polytetrafluoroethylene, benzoguanamine resin, thermosetting epoxy resin, unsaturated polyester resin, thermosetting urea resin, and thermosetting phenol resin are also preferably used. The particles (C) to be contained in the composition constituting the heat seal layer may be selected from, for example, the above-mentioned inorganic particles and organic particles according to the purpose. In many cases, it is advantageous to select inorganic particles that have a relatively high anti-blocking effect and that are advantageous in terms of cost.

  The average particle diameter of the inorganic particles suitable as the particles (C) and the organic particles is not particularly limited, but is preferably 0.01 to 10 μm, more preferably 3 to 6 μm. In particular, in order to suppress an increase in haze value and to impart an appropriate slip, that is, by controlling the film haze: Ha (%) of the polylactic acid resin film to 1% or more and 10% or less, and at the same time polylactic acid resin The coefficient of dynamic friction between the heat seal layers of the film: In order to control μd to 0.5 or less, the composition constituting the heat seal layer of the polylactic acid resin film of the present invention has an average particle size of 3 to 6 μm. It is preferable to contain particles (C) (inorganic particles and / or organic particles). Note that the average particle diameter here is the cumulative median diameter (Median diameter), that is, the cumulative curve is 50% when the cumulative curve is determined with the total volume of the aggregate of powders being 100%. Particle diameter (50% diameter [μm]), which can be determined by a microtrack FRA laser particle size distribution analyzer or the like.

  When the composition constituting the heat seal layer of the polylactic acid-based resin film contains the aforementioned particles (C), particularly particles (C) having an average particle diameter of 3 to 6 μm, the content increases. In view of suppressing moderate slipperiness, that is, controlling the film haze: Ha (%) of the polylactic acid resin film to 1% or more and 10% or less, and at the same time, dynamic friction between the heat seal layers of the polylactic acid resin film Coefficient: From the viewpoint of controlling μd to 0.5 or less, 0.05% by mass or more and 1% by mass or less are preferable in 100% by mass of the composition constituting the heat seal layer, and 0.1% by mass or more from the same viewpoint. 0.6 mass% or less is more preferable.

  That is, aliphatic polyester and / or fat other than the polylactic acid resin (A), (A) in the composition constituting the heat seal layer of the polylactic acid resin film in the case of containing the particles (C) described above. The preferable content of the aromatic aromatic polyester (B) and the particles (C) is such that (A) is 79% by mass or more and 89.95% by mass or less, and (B) is 10% by mass or more, 20% in 100% by mass of the composition. It is a preferred embodiment that the mass% or less and (C) is 0.05 mass% or more and 1 mass% or less.

The composition which comprises the heat seal layer of the polylactic acid resin-type film of this invention may contain a plasticizer in the range which does not impair the effect of this invention. Examples of plasticizers include, for example, phthalate esters such as diethyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, di-1-butyl adipate, di-n-octyl adipate, di-n-butyl sebacate , Aliphatic dibasic acid esters such as di-2-ethylhexyl azelate, phosphate esters such as diphenyl-2-ethylhexyl phosphate and diphenyloctyl phosphate, tributyl acetylcitrate, tri-2-ethylhexyl acetylcitrate , Hydroxy polycarboxylic esters such as acetyl citrate tributyl, fatty acid esters such as methyl acetyl ricinoleate and amyl stearate, polyhydric alcohol esters such as glycerin triacetate and triethylene glycol dicaprylate, epoxidized soybean , Epoxy plasticizers such as epoxidized linseed oil fatty acid butyl ester and octyl epoxy stearate, polyester plasticizers such as polypropylene glycol sebacate, polyalkylene ethers, ether esters, acrylates, etc. Among them, a mixture of plural kinds of plasticizers is also included. In particular, the solubility parameter of all plasticizers added to the film in order to suppress bleed out, maintain transparency and increase plasticization efficiency: SP is (16-23) ^1/2 MJ / m ³ Is more 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 plasticizers, a biodegradable plasticizer is preferable from the viewpoint of keeping the biodegradability of the entire film.

  In consideration of suitability for food packaging applications, plasticizers approved by the US Food and Sanitation Administration (FDA), the Sanitation Council for Polyolefins, etc. are preferred. Examples of such plasticizers include triacetin, epoxidized soybean oil, epoxidized linseed oil, epoxidized linseed oil fatty acid butyl ester, adipic acid-based aliphatic polyester, acetyl citrate tributyl, acetyl ricinoleic acid ester, glycerin fatty acid ester, sucrose Examples thereof include fatty acid esters, sorbitan fatty acid esters, adipic acid dialkyl esters, bis (alkyldiglycol) adipates, and polyethylene glycols.

  Furthermore, from the viewpoint of durability at the time of storage before use including suppression of bleed out of the plasticizer, blocking of the film, and dimensional stability, for example, when the plasticizer is used in the present invention, the number average molecular weight is 1,000 or more. It is preferable that the plasticizer is a solid plasticizer at room temperature, such as polyethylene glycol.

  The thickness of the polylactic acid-based resin film of the present invention is not particularly defined, but when it is formed by an inflation method, it is usually preferably a film having a thickness of 10 μm to 120 μm. If the thickness is less than 10 μm, the film may be insufficient in stiffness. Further, when the thickness exceeds 120 μm, the packaging material may be too strong, and when it is used for various packaging applications, the handling property may be inferior. In particular, in the inflation film-forming method, bubbles tend to become unstable due to their own weight. From the same viewpoint, the polylactic acid resin film of the present invention preferably has a thickness of 15 μm or more and 60 μm or less.

  In addition, the polylactic acid-type resin film of this invention is a single unit of only the heat seal layer which consists of a composition containing the said polylactic acid-type resin (A) and the said aliphatic polyester and / or aliphatic aromatic polyester (B). In the case of a layer structure, naturally, the thickness of the heat seal layer itself matches the thickness of the polylactic acid resin film, that is, the thickness of the heat seal layer is preferably 10 μm or more and 120 μm or less, and 15 μm or more and 60 μm or less. It is more preferable that

  Further, when the polylactic acid resin film of the present invention has a laminated structure having a layer having a composition different from that of the heat seal layer, the ratio of the thickness of the heat seal layer to the total thickness of the polylactic acid resin film is 100%. (%) Is not particularly defined, but from the viewpoint of film formation stability, the ratio of the thickness of the heat seal layer to the total thickness of 100% is usually from 5% to 95%, preferably from 10% to 90%.

The polylactic acid-based resin film of the present invention has a reduced strength due to hydrolysis of the polylactic acid-based resin, particularly in applications that do not require biodegradability, such as packaging for various industrial products, or where it is preferable to have storage durability. From the viewpoint of suppressing the above and imparting good durability, the carboxyl group terminal concentration in the heat seal layer of the film is preferably 0 equivalent / 10 ³ kg or more and 30 equivalent / 10 ³ kg or less, more preferably It is 20 equivalents / 10 ³ kg or less, more preferably 10 equivalents / 10 ³ kg or less. When the carboxyl group terminal concentration in the heat seal layer of the film is 30 equivalents / 10 ³ kg or less, the carboxyl group terminal concentration, which also serves as a hydrolysis autocatalyst, is sufficiently low. In many cases, it is possible to impart such durability.

Examples of the method for setting the carboxyl group terminal concentration in the heat seal layer of the film to 30 equivalents / 10 ³ kg or less include, for example, a method of controlling by a catalyst or heat history during synthesis of the polylactic acid resin (A), the heat Examples thereof include a method of reducing a heat history such as lowering an extrusion temperature at the time of film formation including a seal layer or shortening a residence time, a method of blocking a carboxyl group terminal using a reactive compound, and the like.

  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 heat seal layer of the film is blocked, and it is more preferable that the whole amount 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 a carbodiimide compound is particularly preferable from the viewpoint of reaction efficiency.

Next, the method for producing the polylactic acid resin film of the present invention will be specifically described.
The polylactic acid resin (A) in the present invention can be obtained, for example, by the following method. As a raw material, the main component is a lactic acid component of L-lactic acid or D-lactic acid, 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 (A) 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.

  In obtaining the composition containing polylactic acid-type resin (A) and aliphatic polyester other than polylactic acid and / or aliphatic aromatic polyester (B) in this invention, the solution which melt | dissolved each component in the solvent is used. It is possible to produce a composition by removing the solvent after uniform mixing, but there is no need for steps such as dissolution of the raw material in the solvent and removal of the solvent. It is preferable to adopt a melt-kneading method for producing the composition by doing so. 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 productivity, it is preferable to use a single screw or 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 200 ° C. to 220 ° C. from the viewpoint of preventing the deterioration of the polylactic acid resin (A).

  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 composition obtained by the above-described method. The inflation method is preferably employed in order to provide the object of the present invention, in particular, to provide excellent properties at the same time as the packaging material, and at the same time to provide high economic efficiency.

  In producing the polylactic acid-based resin film of the present invention, for example, when the composition obtained by the above-described method is once chipped, and melt-kneaded again to perform extrusion / film formation, the chip is kept at 60 to 110 ° C. It is preferable to use after setting the moisture content to 500 ppm or less by drying for 6 hours or more. Furthermore, by carrying out vacuum drying under a high vacuum with a degree of vacuum of 10 Torr or less, the lactide content in the composition containing the polylactic acid resin (A) and the like is reduced, thereby preventing hydrolysis during melt-kneading. This is also preferable because it can prevent a decrease in molecular weight, and can have a melt viscosity at an appropriate level when a composition containing the polylactic acid resin (A) or the like is used, and can stabilize the film forming process. From the same point of view, it is preferable to directly use the film forming process without forming chips once, or when melt extrusion / film forming, use a twin screw extruder with a vacuum vent hole to reduce moisture and low It is preferable to perform melt extrusion while removing volatiles such as molecular weight.

  When the polylactic acid-based resin film of the present invention is produced by an inflation method, for example, the polylactic acid-based resin (A) adjusted to have a desired ratio and the aliphatic polyester and / or the aliphatic aromatic polyester (B). The dry blend is melt-extruded with a twin-screw extruder with a vacuum vent hole, led to an annular die, extruded from the annular die, and supplied with dry air to form a balloon (bubble). After air-cooling and solidification, folding at a predetermined take-up speed while being folded flat with a nip roll, both ends or one end may be cut open as necessary.

  In this case, it may be adjusted to a desired thickness according to the discharge amount from the annular die, the take-up speed of the nip roll, and the bubble blow ratio, but in order to improve the thickness accuracy and uniformity, the annular die is a spiral type. It is good to use.

  In addition, the extrusion temperature of the composition containing the polylactic acid resin (A) or the like is usually in the range of 150 to 240 ° C., but the temperature of the annular die is important in order to improve the thickness accuracy and uniformity, The temperature of the annular die is 150 to 190 ° C, preferably 150 to 170 ° C. If the temperature of the annular die is less than 150 ° C., the temperature at which the composition is extruded is too low, the molding behavior at the time of blow-up immediately after discharge becomes uneven, the thickness accuracy deteriorates, and the winding shape becomes poor. When a film is formed because the stress at the time of up is too high, the heat shrinkage rate is high, and the winding shape is further deteriorated by so-called winding tightening over time. On the other hand, when the temperature of the annular die exceeds 190 ° C., the viscosity of the composition is too low, the thickness accuracy is deteriorated and the winding shape is poor, and the bubble formation itself tends to be unstable. From the same viewpoint, the temperature of the annular die is more preferably 160 to 170 ° C.

  The blow ratio of the bubble depends on the relationship between the discharge amount and the take-up speed of the nip roll, but the film may be anisotropic if it is too low or too high. It tends to be unstable and is usually in the range of 2.0 to 4.0.

  Furthermore, 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 resin film of the present invention is excellent in heat sealability, impact resistance, and transparency, it is particularly suitable for packaging materials. In particular, the polylactic acid resin film of the present invention can be used as various bags by processing.

  One of the bags according to the present invention is characterized in that the surface of the heat-seal layer of the polylactic acid resin film of the present invention and a non-woven fabric mainly composed of the polylactic acid resin have a side directly bonded. It is a bag to do. Here, having a directly bonded side means that at least one side of the bag has a surface of the heat seal layer of the polylactic acid-based resin film and a non-woven fabric mainly composed of the polylactic acid-based resin without using an adhesive or the like. And are attached.

  The nonwoven fabric used for the bag of the present invention is obtained by a conventional method, and the production method is not particularly limited, but for example, those obtained by a spun bond method or a melt blow method can be suitably used. It is important that the nonwoven fabric is mainly composed of a polylactic acid resin. By having a polylactic acid-based resin as a main component, good heat-sealability with the polylactic acid-based resin film of the present invention is exhibited. In addition, the polylactic acid-type resin which comprises a nonwoven fabric can use resin similar to the above-mentioned polylactic acid-type resin (A). Moreover, the main component in the nonwoven fabric mainly composed of a polylactic acid resin means that the polylactic acid resin is contained in an amount of 50% by mass or more and 100% by mass or less in 100% by mass of the total resin composition constituting the nonwoven fabric.

  In the bag of the present invention, for example, after the surface of the heat seal layer of the polylactic acid resin film and the nonwoven fabric mainly composed of the polylactic acid resin are overlapped, at least one side is heat sealed, The surface of the heat seal layer of the resin film and the nonwoven fabric mainly composed of polylactic acid resin can be obtained by providing a directly bonded side, but it is important that the heat seal location has at least one side, Alternatively, three-side heat sealing may be performed. When a rectangular polylactic acid resin film and a rectangular nonwoven fabric are overlapped and one side is heat-sealed, the other two locations can be bonded with an adhesive or the like.

  Another bag of the present invention is a bag characterized in that at least one side is directly bonded to the polylactic acid resin film of the present invention. The bag of this embodiment is characterized in that at least one side is bonded by heat sealing using the polylactic acid resin film of the present invention without using a non-woven fabric. Here, “directly bonded” means that at least one side of the bag is bonded to each other without interposing an adhesive or the like.

  As a bag of this aspect, for example, two sheets of the polylactic acid-based resin film of the present invention are prepared, and at least one heat seal layer is overlapped with another film, and at least one side is heat sealed, The other two sides can be sealed with an adhesive or the like, or the other two sides can be heat sealed to obtain a bag. A bag can also be obtained by preparing one sheet of the polylactic acid-based resin film of the present invention, folding it back and heat-sealing two sides.

  Still another bag of the present invention is a bag characterized in that at least one side of the tube-shaped polylactic acid resin film of the present invention is directly bonded. Here, as described above, the fact that at least one side of the bag obtained by using the tube-shaped polylactic acid resin film does not pass through an adhesive or the like between the polylactic acid resin films. It means that it is adhered.

  In order to obtain the bag of this aspect, after forming the polylactic acid resin film of the present invention into a tube shape, it can be obtained by adhering at least one side by heat sealing. As a method for forming a seamless tube-like film, a general inflation method or a tubular stretching method can be suitably applied.

  The polylactic acid-based resin film of the present invention can also be suitably used as a banding tape used when bundling a PTP (press-through pack) package such as a medicine.

  Moreover, the polylactic acid-based resin film of the present invention is prepared, for example, by preparing two sheets of the polylactic acid-based resin film of the present invention so that these heat seal layers face each other, and further bonding three sides by heat sealing, By putting a pillow from the remaining one side, it can be suitably used as a pillow bag.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited thereto.

Measurements and evaluations shown in the examples were performed under the following conditions.
[Measurement and evaluation method]
(1) Melt mass flow rate: MFR (g / 10 min)
According to JIS-K-7210 (1999), the melt mass flow rate value: MFR (g / 10 min) of an aliphatic polyester and / or an aliphatic aromatic polyester under a load of 2.16 kg at 190 ° C. was determined.
(2) Heat seal strength between heat seal layers: Hs (N / 15 mm)
A strip-shaped measurement sample having a width of 15 mm was prepared with the measurement direction (MD direction) as the long side. “Heat seal tester” TP-701S type manufactured by tester industry, hot plate shape: flat metal / rubber (one side heating), hot plate temperature: 120 ° C., surface pressure: 1 kgf / cm ² , seal Time: Create a test sample in 1 second, and use “Tensilon Universal Testing Machine” UTC-100 type manufactured by Orientec Co., Ltd., peeling direction: MD direction, peeling speed: 200 mm / min. Heat seal strength: Hs (N / 15 mm) was determined. The measurement was performed 5 times for each level, and the average value of the 5 measurements was obtained.

  Moreover, about the destruction condition, it judged visually by the following references | standards.

○ (excellent): peeling + sample destruction (thickness fluctuates or the sample cuts as the peeling progresses)
X (impossible): peeling (peeling while maintaining the thickness of the sample, or not bonding)
(3) Film haze: Ha (%)
In accordance with JIS-K-7105 (1981), the haze value was measured using a “haze meter” HGM-2DP type manufactured by Suga Test Instruments Co., Ltd. The measurement was performed 5 times for each level, and the average value of the 5 measurements was determined according to the following formula.
Haze: Ha (%) = Td / Tt × 100
Td: diffuse transmittance, Tt: total light transmittance was determined according to the following criteria.
○ (excellent): Ha ≦ 10%.
Δ (good): Ha> 10%.
(4) Coefficient of dynamic friction between heat seal layers of film: μd
According to JIS-K-7125 (1999), a slip tester manufactured by Toyo Tester Kogyo Co., Ltd. was used, and the load was 200 g, and the value was obtained from the resistance (μd: dynamic friction coefficient) in the stable region after sliding using the following formula. It was.

Coefficient of dynamic friction: μd = resistance value / load (5) End crack resistance in the winding length direction and width direction (direction orthogonal to the winding length direction) When testing the winding length direction, the winding length direction is the longitudinal direction. A direction was cut into a strip shape having a width of 20 mm, and measured with a Tensilon tensile tester according to JIS-C-2111 (2002). The sample was passed through a V-shaped jig set in a tensile tester and pulled at a speed of 200 mm / min to obtain the stress (N / 20 mm) when the sample was torn.

Also in the case of testing the width direction, it was cut into a strip shape having a width of 20 mm with the width direction as a longitudinal direction, and measurement was performed in the same manner as described above.
(6) Wrinkles and Tarmi After storing the roll sample for 3 days in an atmosphere of temperature 23 ° C. and humidity 65% RH, an iron shaft with a diameter smaller than the inner diameter of the paper tube is passed through the paper tube of the roll sample, and both ends of the iron shaft The roll was placed in a state where it was hooked horizontally and freely rotated, the film was unwound from the roll sample by about 2 m in the horizontal direction, visually observed, and judged according to the following criteria.
○ (excellent): Wrinkles and tarmi are not recognized, and there is no problem in flatness.
△ (good): Although wrinkles and tarmi are slightly observed, if the roll is fixed in a state where it cannot freely rotate and tension is applied in the winding length direction of the film and a strain of 1% or less is applied, no wrinkles or tarmi are observed. .
X (impossible): Wrinkles and tarmi are also observed in the above.
(7) Comprehensive judgment Comprehensive judgment was judged on the following criteria.
○ (excellent): Destruction status (heat seal), haze, wrinkle and tarmi are all judged as ○.
Δ (good): At least one judgment of haze and wrinkle / tarmi is Δ.
X (impossible): At least one judgment of destruction status (heat seal), wrinkles and tarmi is x.

[Polylactic acid resin used]
(Polylactic acid PL1)
Mass average molecular weight = 220,000, D-form content = 1.4%, melting point = 166 ° C.,
Moisture content = 360 ppm,
(Polylactic acid PL2)
Mass average molecular weight = 220,000, D-form content = 5.0%, melting point = 150 ° C.,
Moisture content = 360 ppm,
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.
[Used aliphatic polyester resin]
(Polyester PA1)
Polybutylene succinate / adipate resin (made by Showa Polymer Co., Ltd., trade name “Bionore” # 3001), MFR = 1.4
(Polyester PA2)
Polybutylene succinate and adipate resin (Mitsubishi Chemical Corporation, trade name “GSPla” AD92W), MFR = 4.5
(Polyester PA3)
Polybutylene succinate / adipate resin (made by Showa Polymer Co., Ltd., trade name “Bionore” # 3003), MFR = 5
(Polyester PA4)
Polybutylene succinate / adipate resin (made by Showa Polymer Co., Ltd., trade name “Bionore” # 3020), MFR = 25
(Polyester PA5)
Polybutylene succinate resin (product name “Bionore” # 1003, manufactured by Showa Polymer Co., Ltd.), MFR = 5
(Polyester PA6)
Polybutylene terephthalate / adipate resin (trade name “Ecoflex”, manufactured by BASF), MFR = 5
[Used particles]
(Inorganic particles SL1)
Calcium carbonate (manufactured by Maruo Calcium Co., Ltd., trade name “Caltex RR”), average particle size = 4 μm
(Inorganic particles SL2)
Calcium carbonate (manufactured by Maruo Calcium Co., Ltd., trade name “Caltex®”), average particle size = 2.8 μm
The average particle diameter is the cumulative median diameter (Median diameter), that is, the particle at which the cumulative curve becomes 50% when the cumulative curve is obtained by setting the total volume of the powder aggregate to 100%. It was a diameter (50% diameter [μm]), and was determined by a Microtrac FRA laser type particle size distribution analyzer.
[Preparation of polylactic acid resin film]
(Examples 1, 2, 4, 5, 9 and Comparative Examples 2 to 4, 6)
A film was formed by an inflation method using a mixture of polylactic acid and aliphatic polyester and / or aliphatic aromatic polyester in the proportions shown in Table 1. That is, the mixture was supplied to a single screw extruder having a cylinder temperature of 190 to 210 ° C. and a screw diameter of 65 mm, and a blow ratio: 2.5 from a spiral annular die having a diameter of 200 mm, a lip clearance of 1.0 mm, and a temperature of 165 ° C. Extruded upward in a bubble shape, air cooled with a cooling ring, folded at 25 m / min while folded with a nip roll above the die, cut at both ends with an edge cutter and cut into two pieces, each wound with a winder It was. A film having a final thickness of 25 μm was obtained by adjusting the discharge amount. The film formation was stable without breaking for 2 hours. However, only in Comparative Example 3, bubbles were unstable and a stable film was impossible. The evaluation results of the obtained film are shown in Table 1.

(Examples 3 and 8, Comparative Example 1)
An SL1 master chip prepared by melt-kneading the polylactic acid PL2 as a base chip in advance so as to be inorganic particles SL1: 30% by mass was prepared. In addition to polylactic acid and aliphatic polyester, an SL1 master chip was used, and a mixture in which each component had a ratio shown in Table 1 was used (for example, in Comparative Example 1, polylactic acid PL2: 98.3% by mass). And a SL1 master chip: a mixture of 1.7% by mass), a film having a final thickness of 25 μm was obtained in the same manner as in Example 1. The film formation was stable without breaking for 2 hours. The evaluation results of the obtained film are shown in Table 1.
(Example 6)
In advance, an SL2 master chip was prepared by melt-kneading the polylactic acid PL2 as a base chip so that the inorganic particle SL2 was 30% by mass. In addition to polylactic acid and aliphatic polyester, an SL2 master chip was used, and a mixture in which each component had a ratio shown in Table 1 was used (polylactic acid PL2: 98.3 mass% and SL2 master chip: 1. A film having a final thickness of 25 μm was obtained in the same manner as in Example 1 except that the mixture was 7% by mass. The film formation was stable without breaking for 2 hours. The evaluation results of the obtained film are shown in Table 1.
(Example 7, Comparative Example 5)
Using a polylactic acid, aliphatic polyester, SL1 master chip prepared in the same manner as in Comparative Example 1 and the like, and using a mixture in which each component has a ratio shown in Table 1, respectively, by a T-die cast biaxial stretching method A film was formed. That is, the above mixture is supplied to a single screw extruder having a cylinder temperature of 190 to 210 ° C. and a screw diameter of 65 mm, extruded from a T die having a width of 300 mm, a lip clearance of 1.0 mm and a temperature of 190 ° C., and cast into a mirror drum having a temperature of 25 ° C. Then, it is stretched 2.5 times with a stretching roll at a temperature of 75 ° C. in the flow direction, further stretched 3 times in the width direction in a tenter at a temperature of 80 ° C., and then heated at 130 ° C. The edge portion was cut by setting treatment and wound up at 10 m / min. A film having a final thickness of 25 μm was obtained by adjusting the discharge amount. The film formation was stable without breaking for 2 hours. The evaluation results of the obtained film are shown in Table 1.

  The polylactic acid-based resin films of Examples 1 to 9 were excellent in heat-sealing properties, and were of a quality having no practical problems such as haze, roll wrinkles and tarmi.

On the other hand, in Comparative Examples 1 to 6, the aliphatic polyester is not contained (Comparative Examples 1 and 5), the aliphatic polyester is contained, but the MFR is outside the scope of the present invention (Comparative Examples 2 and 3). Since the content is outside the range of the present invention (Comparative Examples 4 and 6), the heat sealability was insufficient.
(Example 10)
A film obtained in the same manner as in Example 3 and a polylactic acid non-woven fabric having a basis weight of 40 g are overlapped and cut into a square having a side of 125 mm, and the three sides of the end are heated at a plate temperature of 120 ° C. and a surface pressure of 1 kgf. / Cm ² , seal time: 1 second, seal width: 2 mm, and bonded by heat sealing to prepare a bag sample having a film on one side and a nonwoven fabric on one side.

The prepared sample has a good appearance including the seal part, has a sufficient strength when a CD (compact disc) is taken in and out, and has a good visibility of the CD label part. There was no problem.
(Example 11)
A mixture of polylactic acid and aliphatic polyester in the same proportion as in Example 3 described in Table 1 was supplied to a single screw extruder having a cylinder temperature of 190 to 210 ° C. and a screw diameter of 45 mm, and a diameter of 100 mm, a lip clearance of 1.0 mm, Extruded upwards in a bubble shape at a blow ratio: 2.0 from a spiral annular die with a temperature of 165 ° C, air-cooled with a cooling ring, taken up at 25 m / min while folded with a nip roll above the die, and kept in a tube shape Rolled up. By adjusting the discharge amount, a tubular film having a final thickness of 25 μm and a folding width of about 314 mm was obtained.

This tubular film is cut into a length of 470 mm in the winding length direction, and one side of the cut portion is heated at a plate temperature of 130 ° C., a surface pressure of 1 kgf / cm ² , a seal time of 1 second, and a seal width. : Bonded by heat sealing at 5 mm to prepare a bag sample.
The prepared sample had a good appearance including the seal part, and I tried putting one 500 ml PET bottle filled with the contents, but there was no problem in carrying around without removing the bottom.
(Example 12)
In the same manner as in Example 3, a film obtained by changing only the final thickness to 30 μm by adjusting the discharge amount is slit to a width of 40 mm, and an automatic banding machine manufactured by Omori Machine Industry Co., Ltd .: BM-510 type is used. A banding packaging sample of 10 bundles of PTP (press-through pack) packaging was prepared.

The prepared sample, including the seal part, had no wrinkles and no sagging and had a good appearance, and was a packaging with sufficient strength for practical use.
(Example 13)
The film obtained in the same manner as in Example 3 was slit into a width of 210 mm, and a product made by Fujikikai Corporation, a forward pillow packaging machine (horizontal pillow packaging type): FW3200 / B type, frontage 92 mm, cut length 190 mm, The center seal was a palm type, the width was 13 mm, and the seal width of the frontage was 13 mm. A set temperature of the heat seal roll for the center seal was set to 130 ° C., a set temperature of the front seal bar was set to 140 ° C., and bags were made at a rate of 100 bags / minute to prepare pillow package samples.

  The prepared sample was free of wrinkles and sagging including the seal part, had a good appearance, had good visibility of the contents, and had no problem in practical use of the strength of the seal part.

  The present invention is applied as a packaging material. In particular, by bonding the heat seal layer of the present invention, it is suitable as various bags. The polylactic acid-based resin film of the present invention is an excellent polylactic acid-based resin film excellent in heat sealability, impact resistance, transparency, and suitable for the inflation method, which is a relatively inexpensive facility. It can be preferably used for various packaging applications such as bags for industrial products, bags for miscellaneous goods such as CD cases, food bags such as vegetables and fruits, tube bags, pillow bags, and banding tapes.

Claims (8)

  Melt mass flow rate under a load of 2.16 kg at 190 ° C. with MFR (g / 10 minutes) of 3 (g / 10 minutes) or more, 9 ( g / 10 min) having at least one heat seal layer comprising a composition containing 5% by mass or more and 35% by mass or less of an aliphatic polyester and / or an aliphatic aromatic polyester (B) other than (A). Heat seal strength between heat seal layers: Hs is 7 (N / 15 mm) or more, Polylactic acid resin film characterized by the above-mentioned.   The polylactic acid resin film according to claim 1, wherein the aliphatic polyester and / or the aliphatic aromatic polyester (B) is a polybutylene succinate resin.   The polylactic acid resin film according to claim 1 or 2, wherein the polylactic acid resin film has a single-layer structure composed of only a heat seal layer.   Film haze: Ha (%) is 1% or more and 10% or less, The polylactic acid-type resin film in any one of Claims 1-3 characterized by the above-mentioned.   The coefficient of dynamic friction between heat seal layers of the polylactic acid-based resin film: μd is 0.5 or less, and the polylactic acid-based resin film according to any one of claims 1 to 4.   The end resistance is 30 (N / 20 mm) or more and 90 (N / 20 mm) or less in both the winding length direction (MD direction) and the width direction (direction orthogonal to the winding length direction: TD direction). The polylactic acid resin film according to any one of claims 1 to 5,   The polylactic acid resin film according to any one of claims 1 to 6, wherein the composition contains particles (C) having an average particle size of 3 µm or more and 6 µm or less.   The bag using the polylactic acid-type resin film in any one of Claims 1-7.