JPWO2013038770A1 - the film - Google Patents

Abstract

The present invention provides a film having improved flexibility and tear propagation resistance. The present invention includes (A) a polylactic acid resin, (B) an aliphatic polyester resin excluding the polylactic acid resin, and / or Or it is a film containing an aliphatic aromatic polyester-based resin and (C) a transesterification catalyst and / or a transesterification catalyst-derived compound.

Description

  The present invention relates to a film containing a polylactic acid resin, an aliphatic polyester resin excluding the polylactic acid resin and / or an aliphatic aromatic polyester resin, in order to improve its flexibility and tear propagation resistance. The present invention relates to a film containing a catalyst and / or a compound derived from a transesterification catalyst.

  In recent years, due to increasing environmental awareness, there are concerns about soil pollution problems caused by the disposal of plastic products and global warming problems caused by increased carbon dioxide caused by incineration of the products. As a countermeasure against the former, biodegradable resin that is completely decomposed into carbon dioxide molecules and water molecules under the environment in the soil, and as a countermeasure against the latter, synthesized from biological raw materials such as plants and incinerated Research and development on biomass resins that do not impose a new carbon dioxide load in the atmosphere are being actively conducted.

  Attention to polylactic acid-based resins is increasing as it is compatible with both of them and is relatively advantageous in terms of cost. However, since the polylactic acid resin is rigid and brittle, its flexibility and tear propagation resistance when formed into a film are relatively small, and as a result, it is difficult to use as a substitute for a polyolefin-based soft film such as polyethylene. . Therefore, various attempts have been made to improve these properties of the polylactic acid-based resin and put it into practical use as a flexible film.

For example, Patent Document 1 discloses a film made of a composition containing a polylactic acid-based resin and a plasticizer and defining elongation, thickness, and heat shrinkage rate. Patent Document 2 discloses a biodegradable polymer composition mainly composed of a mixture of two or more of a polylactic acid resin, a glycol / aliphatic dicarboxylic acid copolymer, and polycaprolactone. Disclosed are compositions and shrink films that may contain agents, heat stabilizers, and the like. Patent Document 3 discloses a composition having excellent impact resistance and transparency, which contains a biodegradable polyester resin and an alkylsulfonic acid metal.
JP 2009-138085 A JP-A-9-169896 JP 2009-144152 A

  In the above-mentioned patent document, although there is a description relating to improvement in flexibility and / or impact resistance of a polylactic acid-based resin film, no technology relating to improvement in tear propagation resistance is disclosed at all. In particular, previous reports on the technical idea related to the addition of a transesterification catalyst that leads to an improvement in the tear propagation resistance of the film are not sufficient.

  The present invention solves such a conventional problem, whereby a film containing a polylactic acid-based resin, an aliphatic polyester-based resin excluding the polylactic acid-based resin and / or an aliphatic aromatic polyester-based resin, It is intended to improve tear propagation resistance.

  In order to solve the above problems, the present invention proposes the following configurations. That is, (A) polylactic acid resin, (B) aliphatic polyester resin and / or aliphatic aromatic polyester resin excluding polylactic acid resin, and (C) transesterification catalyst and / or transesterification catalyst A film containing a compound.

  The (C) transesterification catalyst in the film of the present invention is preferably a metal salt or a sulfur acid.

  Furthermore, the (C) transesterification catalyst in the film of the present invention is a metal salt of an organic acid having an alkyl group having 0 to 5 carbon atoms, a halogenated metal salt, or an alkyl having 0 to 5 carbon atoms. A sulfur acid having a group is more preferable.

  The film of the present invention contains a block copolymer having a polylactic acid segment and an aliphatic polyester segment excluding polylactic acid, and / or a block copolymer having a polylactic acid segment and an aliphatic aromatic polyester segment. It is preferable.

  In the DSC measurement, the film of the present invention has a melting peak temperature derived from (A) polylactic acid-based resin in the first temperature raising process and Tm1, derived from (A) polylactic acid-based resin in the first temperature raising process. When the melting peak temperature is Tm2, it is preferable to have the following relationship.

0.1 ≦ Tm1-Tm2 ≦ 1
Moreover, when manufacturing the film of this invention, it is preferable to add 0.01-10 mass parts of phosphorus compounds with respect to 100 mass parts of (A) polylactic acid-type resin.

  The film of the present invention preferably contains (E) a plasticizer.

  The (E) plasticizer in the film of the present invention is preferably a block copolymer having a polylactic acid segment and a polyether segment.

  It is preferable that polybutylene adipate terephthalate is contained as the aliphatic polyester resin excluding (B) the polylactic acid resin and / or the aliphatic aromatic polyester resin in the aliphatic aromatic polyester resin in the film of the present invention. .

  According to the present invention, it is possible to improve the flexibility and tear propagation resistance of a film containing a polylactic acid resin, an aliphatic polyester resin excluding the polylactic acid resin, and / or an aliphatic aromatic polyester resin. It becomes possible. The film of the present invention is required to have high flexibility and high tear propagation resistance, agricultural and forestry applications such as agricultural multi-films and pine fumigation sheets, garbage bags and compost bags, and food products such as vegetables and fruits It can be preferably used for various packaging applications such as bags for industrial use and bags for various industrial products.

  The film of the present invention is a polylactic acid resin, an aliphatic polyester resin excluding the polylactic acid resin and / or a film containing an aliphatic aromatic polyester resin, in order to improve its flexibility and tear propagation resistance, It contains a transesterification catalyst and / or a transesterification catalyst-derived compound.

Hereinafter, the film of the present invention will be described.

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

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

  However, the (A) polylactic acid-based resin of the present invention includes (D) a block copolymer having a polylactic acid segment and an aliphatic polyester segment excluding polylactic acid described later, and a polylactic acid segment and an aliphatic aromatic. The block copolymer having a polyester segment does not correspond to the (A) polylactic acid resin.

  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, and 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 of the present invention is measured with a differential scanning calorimeter (DSC) at a temperature rising rate of 20 ° C./min after leaving the polylactic acid resin to stand for 1 hour under heating at 100 ° C. In this case, it means 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 melting point when measured in the same manner.

  As will be described later, the polylactic acid resin is preferably a mixture of a crystalline polylactic acid resin and an amorphous polylactic acid resin.

  The polylactic acid resin used in the present invention may randomly 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 as described above is preferably 0 to 30 mol% with respect to 100 mol% of the whole monomer units in the polymer of the polylactic acid resin, and is 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 the main component is poly L-lactic acid, conversely, when the main component is poly D-lactic acid, poly L-lactic acid, respectively, It is also preferable to mix a small amount. The reason is that the stereocomplex crystal formed thereby plays a role as a crystal nucleating agent for polylactic acid-based resins, and maintains transparency of the film compared to the case where a normal crystal nucleating agent is added. Because it can. 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 efficient formation of stereocomplex crystals. The mass average molecular weight of the polylactic acid to be mixed in a small amount is preferably 0.5 to 50%, more preferably 1 to 40%, more preferably 2 to 30% of the mass average molecular weight of the main component polylactic acid. More preferably it is.

  Furthermore, the polylactic acid resin used in the present invention is preferably a polylactic acid block copolymer composed of a segment composed of an L-lactic acid unit and a segment composed of a D-lactic acid unit from the viewpoint of improving heat resistance. . In this case, since the polylactic acid block copolymer forms a stereocomplex crystal in the molecule, the melting point is higher than that of a normal crystal. For efficient stereocomplex crystal formation, the segment length should satisfy Y <X / 2 with respect to the mass average molecular weight X of the polylactic acid block copolymer and the maximum mass average molecular weight Y of one segment. preferable.

  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. In addition, the mass average molecular weight in this invention means the molecular weight which measured with the chloroform solvent by the gel permeation chromatography (GPC), and was calculated by the polymethylmethacrylate conversion method.

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

It is preferable that the film of this invention contains 30-95 mass% of polylactic acid-type resin in 100 mass% of the whole composition which comprises a film. By setting the polylactic acid resin content in the composition to 30% by mass or more, the tear propagation resistance and the degree of biomass (content ratio of plant-derived raw materials) of the film are increased. On the other hand, by setting the polylactic acid resin to 95% by mass or less, the film has excellent flexibility. In addition, in 100 mass% of the whole composition which comprises a film, it is more preferable that the content rate of a polylactic acid-type resin is 40-85 mass%, and it is especially preferable that it is 40-70 mass%.

((B) Aliphatic polyester resin and / or aliphatic aromatic polyester resin excluding polylactic acid resin)
In order to improve flexibility and tear propagation resistance, the film of the present invention needs to contain (B) an aliphatic polyester-based resin and / or an aliphatic aromatic polyester-based resin excluding the polylactic acid-based resin. In addition, it is preferable that these resins also have biodegradability in order to develop biodegradability of the film. These resins also play a role of adjusting the biodegradation rate of the film and the melt viscosity of the entire composition constituting the film, and in particular, forming a stable bubble in the inflation film forming method.

  Examples of aliphatic polyester resins other than polylactic acid resins include polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate / 3-hydroxyhexanoate), and poly (3-hydroxy Butyrate 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 is preferably used. .

  As the aliphatic aromatic polyester resin, for example, poly (butylene succinate / terephthalate), poly (butylene adipate / terephthalate) and the like are preferably used.

  In addition, (B) the aliphatic polyester resin and / or aliphatic aromatic polyester resin excluding the polylactic acid resin of the present invention may be a blend and / or copolymer of those listed above. However, a block copolymer having a polylactic acid segment and an aliphatic polyester segment excluding polylactic acid, and a block copolymer having a polylactic acid segment and an aliphatic aromatic polyester segment are (B) a polylactic acid resin. It does not correspond to the aliphatic polyester resin and / or the aliphatic aromatic polyester resin except for.

Among them, (B) aliphatic polyester-based resins and / or aliphatic aromatic polyester-based resins excluding polylactic acid-based resins include polybutylene succinate, It is more preferably at least one selected from the group consisting of polybutylene succinate / adipate, polybutylene succinate / terephthalate, polybutylene adipate / terephthalate, and more preferably an aliphatic aromatic polyester resin. More preferred are polybutylene succinate terephthalate and / or polybutylene adipate terephthalate, and most preferred is polybutylene adipate terephthalate.

The content of the aliphatic polyester resin and / or the aliphatic aromatic polyester resin excluding the polylactic acid resin (B) contained in the film of the present invention is 5% in 100% by mass of the entire composition constituting the film. It is preferable that it is -80 mass%, and it is more preferable that it is 5-60 mass%. When it is 5% by mass or more, an effect of improving flexibility, tear resistance, and impact resistance is easily obtained, and when it is 80% by mass or less, more preferably 60% by mass or less, biodegradability particularly in agricultural and forestry applications. Can be imparted with appropriate biodegradability, and the degree of biomass is preferred. In addition, in 100 mass% of the whole composition constituting the film, the content of (B) the aliphatic polyester resin and / or the aliphatic aromatic polyester resin excluding the polylactic acid resin is 15 to 50 mass%. More preferably.

((C) Transesterification catalyst and / or transesterification catalyst-derived compound)
In order to improve flexibility and tear propagation resistance, it is important that the film of the present invention contains (C) a transesterification catalyst and / or a transesterification catalyst-derived compound.

  The transesterification catalyst in the present invention is not particularly limited, and examples thereof include metals, metal salts, sulfur acids, and nitrogen-containing basic compounds.

  Examples of metals include manganese, magnesium, titanium, zinc, iron, aluminum, cerium, calcium, barium, cobalt, lithium, sodium, potassium, cesium, lead, strontium, tin, antimony, germanium, yttrium, lanthanum, indium, Zirconium etc. are mentioned.

  Examples of the metal salt include salts composed of the above metals and organic acids such as carboxylic acid, sulfur acid, carbonic acid and phenol, nitric acid, phosphoric acid and boric acid. Examples of the metal salt include halides of the above metals (halogenated metal salts), hydroxides of the above metals (metal hydroxides), and the like.

Examples of sulfur acids include sulfuric acid, sulfonic acid compounds, sulfinic acid compounds, and sulfenic acid compounds. Examples of the nitrogen-containing basic compound include quaternary amine salts, tertiary amines, secondary amines, primary amines, pyridines, imidazoles, ammonia and the like.

Among them, the transesterification catalyst in the present invention is preferably a metal salt or a sulfur acid from the viewpoints of dispersibility in the resin, the degree of degradation of the resin and the molecular weight reduction, and the stability of film formation. Furthermore, from the viewpoint of selecting a film forming machine and a pipe that have low corrosivity, a high transesterification catalytic ability per mass, and a type that hardly causes bleed out from the film, the metal salt has 0 to 0 carbon atoms. A metal salt of an organic acid having 5 alkyl groups or a halogenated metal salt is preferable, and the sulfur acid is preferably a sulfur acid having an alkyl group having 0 to 5 carbon atoms. In the present invention, an alkyl group having 0 carbon atoms means that there is no alkyl group in the molecule.

  Furthermore, regarding the film of the present invention, the transesterification catalyst contained in the film of the present invention, considering the possibility of being used for agricultural and forestry applications and applications requiring biodegradability such as garbage bags and compost bags, It is preferable that it is highly safe to living organisms. In addition, when the ability as a transesterification catalyst is selected together, as a particularly preferred transesterification catalyst, a metal salt of an organic acid having an alkyl group having 0 to 5 carbon atoms shown below, or a halogenated metal salt is preferable. Is mentioned. That is, specific examples of the metal salt of an organic acid having an alkyl group having 0 to 5 carbon atoms include, for example, a carboxylic acid having 1 to 5 carbon atoms having no hydroxyl group, magnesium, titanium, zinc, and iron. , A salt made of a metal selected from aluminum, calcium and potassium. Specific examples of the halogenated metal salt are metal halides selected from, for example, magnesium, titanium, zinc, iron, aluminum, calcium, and potassium.

Among these, the most preferable transesterification catalyst includes a metal salt of an organic acid having an alkyl group having 0 to 5 carbon atoms shown below, or a halogenated metal salt. That is, specific examples of the most preferable metal salt of an organic acid having an alkyl group having 0 to 5 carbon atoms include carboxylic acid having 1 to 3 carbon atoms having no hydroxyl group, magnesium, zinc, iron, and calcium. A salt made of a metal selected from Further, specific examples of the most preferable halogenated metal salt are metal halides selected from magnesium, zinc, iron and calcium.

In the film of the present invention, there is no problem in using two or more transesterification catalysts composed of these compounds in combination.

  Further, the polylactic acid-based resin and / or the aliphatic polyester-based resin and / or the aliphatic aromatic polyester-based resin excluding the polylactic acid-based resin already contain a transesterification catalyst derived from each production process. When forming a film using these as raw materials, it is not always necessary to newly add a transesterification catalyst. The transesterification catalyst contained in these raw materials is added to the film of the present invention ( C) Since it is contained in the film as a transesterification catalyst and / or a transesterification catalyst-derived compound, it is preferable.

  The transesterification catalyst content in the present invention is preferably an amount that satisfies the following conditions in the DSC measurement of the film. That is, in the DSC measurement, when the melting peak temperature derived from the polylactic acid resin in the first temperature raising process is Tm1, and the melting peak temperature derived from the polylactic acid resin in the second temperature raising process is Tm2, the following Having a relationship of

0.1 ≦ Tm1-Tm2 ≦ 1
In addition, when there are a plurality of melting peak temperatures derived from the polylactic acid resin, it is preferable that all of them satisfy this relationship.

  In the film of the present invention, the transesterification catalyst contained in the film further promotes the transesterification reaction when the entire film is heated. In the DSC measurement, the first temperature raising process is performed, and in the second temperature raising process, the transesterification further proceeds as compared with the stage of the first temperature raising process. In the film of the present invention, when the transesterification reaction proceeds between the polylactic acid resin and the aliphatic polyester resin and / or the aliphatic aromatic polyester resin excluding the polylactic acid resin, the polylactic acid resin is derived. The melting peak temperature is reduced. Therefore, when a transesterification catalyst is included in the film of the present invention, Tm2 will be lower than Tm1.

  When the film of the present invention contains a transesterification catalyst, if Tm1-Tm2 is less than 0.1, the transesterification reaction is not sufficiently progressed, and the improvement in flexibility and tear propagation resistance of the film can be reduced. There is sex. Moreover, when Tm1-Tm2 exceeds 1, although progress of transesterification is enough, the film forming property of a film may fall by the low molecular weight etc. by side reaction. Therefore, it is preferable to adjust the addition amount of the transesterification catalyst so as to satisfy the formula of 0.1 ≦ Tm1−Tm2 ≦ 1.

In addition, although the standard of the content of the transesterification catalyst in the film of the present invention varies depending on the type thereof, it cannot be described unconditionally. For example, when the transesterification catalyst is magnesium acetate, the content of the transesterification catalyst is 100% by mass. The content of the transesterification catalyst is preferably 0.01% by mass or more and 5% by mass or less for the progress of the transesterification reaction and avoiding molecular weight reduction. More preferably, it is particularly preferably 0.05% by mass or more and 1% by mass or less, and most preferably 0.05% by mass or more and 0.5% by mass or less.

The transesterification catalyst-derived compound in the present invention means that the transesterification catalyst is an aliphatic polyester resin and / or an aliphatic aromatic polyester system excluding (A) polylactic acid resin and (B) polylactic acid resin in the film. This is a compound that has no transesterification function as a result of the deactivation agent acting on the catalyst after the transesterification reaction has proceeded with the resin, and has a transesterification function in the transesterification catalyst. A compound in which a part of the skeleton is replaced with a part of the skeleton of the deactivator, or a compound in which a part of the skeleton of the deactivator is coordinated to a part of the skeleton having a transesterification function in the transesterification catalyst. Since the above-mentioned compounds are preferably used as the transesterification catalyst, the compound obtained from the suitable transesterification catalyst is preferred as the transesterification catalyst-derived compound.

The film of the present invention is preferably obtained by adding a quencher such as a phosphorus compound to (A) the polylactic acid resin. The film of the present invention obtained by adding a quenching agent such as a phosphorus compound is preferable because it contains a transesterification catalyst-derived compound.

  Examples of the deactivator used for converting the transesterification catalyst into the transesterification catalyst-derived compound include phosphorus compounds, carboxylic acids and derivatives thereof, sulfuric acid and derivatives thereof, nitric acid and derivatives thereof, and the like. Especially, from a viewpoint of the deactivation ability with respect to the transesterification catalyst of this invention, a phosphorus compound is preferable and phosphoric acid and phosphorous acid, these esters, and an inorganic metal salt are more preferable. Further, from the viewpoint of hydrolysis resistance of the polylactic acid-based resin, it is particularly preferably a phosphoric acid crystal or phosphorous acid crystal having a purity of 98% or more. These may be used alone or in combination of two or more.

  Examples of the timing for adding the deactivator include a method of adding the deactivator by dry blending after completion of the compound when a two-stage process of compounding and film formation is adopted. Moreover, when using a biaxial extruder for a compound, and when forming a film directly using a biaxial extruder, the method of adding a quencher from the side feeder of a biaxial extruder is mentioned.

  By adding a deactivator and using the transesterification catalyst as a transesterification catalyst-derived compound, the hydrolysis resistance of the film after film formation is improved and the change in physical properties with time is reduced.

When a phosphorus compound is added as a deactivator, the film of the present invention is obtained by adding 0.01 parts by weight or more and 10 parts by weight or less of a phosphorus compound to 100 parts by weight of a polylactic acid resin. It is particularly preferable that it is obtained by adding 0.01 parts by mass or more and 5 parts by mass or less. When the addition amount of the phosphorus compound with respect to 100 parts by mass of the polylactic acid resin when forming the film of the present invention is less than 0.01 parts by mass, the deactivation of the transesterification catalyst becomes insufficient, and the resin is produced at the time of production. May be reduced in molecular weight. On the other hand, when the amount exceeds 10 parts by mass, dispersion failure may occur in the film, which may cause deterioration in film properties.

The content of the transesterification catalyst-derived compound in 100% by mass of the entire film is preferably 0.01% by mass or more and 10% by mass or less. When the content of the transesterification catalyst-derived compound in 100% by mass of the entire film is less than 0.01% by mass, the transesterification reaction and / or deactivation of the transesterification catalyst may be insufficient. When the content of the transesterification catalyst-derived compound in the entire film of 100% by mass exceeds 10% by mass, there is a possibility that the low molecular weight, which is a side reaction at the time of transesterification, may proceed excessively, and the film is dispersed in the film. Defects can occur, which can reduce film properties.

In the case where the transesterification catalyst and / or transesterification catalyst-derived compound contained in the film is a metal, a metal salt, or a compound derived therefrom, the detection and quantification can be performed using atomic absorption spectrometry. Further, when the transesterification catalyst and / or transesterification catalyst-derived compound is a sulfur acid, a nitrogen-containing basic compound, or a compound derived therefrom, the component in the film is extracted with cyclohexane or the like, and then gas chromatography is performed. Allows detection and quantification.

When the quenching agent contained in the film is a phosphorus compound, the detection and quantification can be performed by fluorescent X-ray analysis.

((D) a block copolymer having a polylactic acid segment and an aliphatic polyester segment excluding polylactic acid, and / or a block copolymer having a polylactic acid segment and an aliphatic aromatic polyester segment)
The film of the present invention comprises (A) a polylactic acid resin, (B) an aliphatic polyester resin and / or an aliphatic aromatic polyester resin excluding the polylactic acid resin, (C) a transesterification catalyst and / or a transesterification. Contains catalyst-derived compounds. In order to form a film having such a composition, when the raw materials are melted and kneaded in an extruder, an aliphatic ester excluding (A) polylactic acid-based resin and (B) polylactic acid-based resin by the action of a transesterification catalyst. A transesterification reaction may proceed between the polyester resin and / or the aliphatic aromatic polyester resin. As a result, (D) a block copolymer having a polylactic acid segment and an aliphatic polyester segment excluding polylactic acid and / or a block copolymer having a polylactic acid segment and an aliphatic aromatic polyester segment are partially present. Generate automatically. Since the block copolymer (D) thus produced functions as a compatibilizing agent in the film, (A) an aliphatic polyester resin excluding a polylactic acid resin and (B) a polylactic acid resin, and The compatibility with the aliphatic aromatic polyester resin is improved, thereby improving the flexibility and tear propagation resistance of the film. Therefore, the film of the present invention comprises (D) a block copolymer having a polylactic acid segment and an aliphatic polyester segment excluding polylactic acid, and / or a block copolymer having a polylactic acid segment and an aliphatic aromatic polyester segment. It is preferable to contain a coalescence.

  That is, (A) polylactic acid resin, (B) aliphatic polyester resin and / or aliphatic aromatic polyester resin excluding polylactic acid resin, (C) transesterification catalyst and When a film containing a transesterification catalyst-derived compound is produced, the block copolymer of the above (D) is often included due to the influence of (C) the transesterification catalyst and / or the transesterification catalyst-derived compound. It will be.

  The block copolymer (D) may be produced in advance by a melt kneading method using a transesterification catalyst. That is, (A) a polylactic acid-based resin, (B) an aliphatic polyester-based resin and / or an aliphatic aromatic polyester-based resin excluding the polylactic acid-based resin, (C) a masterbatch containing a transesterification catalyst is prepared in advance. It is a method of adding it at the time of film forming. In that case, at the stage of preparation of the masterbatch, there is an ester exchange reaction between the (A) polylactic acid resin and the (B) aliphatic polyester resin and / or aliphatic aromatic polyester resin excluding the polylactic acid resin. In the stage where the process proceeds sufficiently and the masterbatch is added to perform compounding and film formation, the content of the transesterification catalyst decreases, so that the low molecular weight of the resin due to side reactions is suppressed, and the physical properties of the resulting film There is an advantage that improvement is possible.

When adding a masterbatch, the addition amount in 100 mass% of the whole film is preferably 5 mass% or more and 30 mass% or less. By making the addition amount 5% by mass or more, the effect of adding the block copolymer (D) can be obtained. Moreover, the effect of molecular weight reduction suppression by a masterbatch method is acquired by making addition amount into 30 mass% or less.

((E) Plasticizer)
The film of the present invention preferably contains (E) a plasticizer in order to mainly impart flexibility.

  Although it does not specifically limit as a plasticizer used for this invention, For example, phthalate ester type | system | groups, such as diethyl phthalate, dioctyl phthalate, and dicyclohexyl phthalate, di-1-butyl adipate, di-n-octyl adipate, Aliphatic dibasic acid esters such as di-n-butyl sebacate and di-2-ethylhexyl azelate, phosphate esters such as diphenyl-2-ethylhexyl phosphate and diphenyloctyl phosphate, tributyl acetylcitrate, acetyl Hydroxy polycarboxylic esters such as tri-2-ethylhexyl citrate and tributyl acetyl citrate, fatty acid esters such as methyl acetylricinoleate and amyl stearate, polyhydric alcohols such as glycerin triacetate and triethylene glycol dicaprylate Ester-based, Epoxidized soybean oil, Epoxidized linseed oil Fatty acid butyl ester, Epoxy plasticizer such as octyl epoxy stearate, Polyester plasticizer such as polypropylene glycol sebacate, Polyalkylene ether, Ether ester, Acrylate Etc. Moreover, it is also possible to use a mixture of two or more of these.

In order to suppress bleed out of the plasticizer, maintain transparency of the film and improve plasticization efficiency, the solubility parameter of all the plasticizers contained in the composition constituting the film: SP is (16-23) ^{1 / 2} MJ / m ³ is preferable, and (17 to 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).

  Moreover, it is preferable that the plasticizer used suitably by this invention is a biodegradable plasticizer from a viewpoint of maintaining the biodegradability of the whole film.

  Furthermore, considering the suitability for food packaging applications and the possibility of residual undegraded products remaining in compost and farmland for temporary or agricultural applications, the plasticizer of the present invention is ) Or polyolefin hygiene council or the like. 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 the bleed-out resistance of the plasticizer and the blocking resistance of the film, the plasticizer used in the present invention is, for example, polyethylene glycol having a number average molecular weight of 1,000 or more at room temperature (20 ° C. ± 15 ° C.). It is preferable that it is solid, that is, the melting point exceeds 35 ° C. Note that the upper limit of the melting point of the plasticizer is 150 ° C., in order to match the melt processing temperature with the polylactic acid resin, the aliphatic polyester resin and / or the aliphatic aromatic polyester resin other than the polylactic acid resin. .

  From the same viewpoint, the plasticizer used in the present invention is more preferably a block copolymer having a polylactic acid segment and a polyether segment. Here, it is the polyether segment that actually acts as a plasticizing component. These block copolymers (hereinafter referred to as “block copolymer plasticizer”) will be described below.

  The mass ratio of the polylactic acid segment contained in the block copolymer plasticizer is preferably 50% by mass or less of the entire block copolymer plasticizer, since 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 is 1,200 or more, sufficient affinity is produced between the block copolymer plasticizer and the polylactic acid resin, and a part of the segment Is incorporated into crystals formed from polylactic acid-based resins and forms so-called eutectics, thereby causing the plasticizer to be anchored to the polylactic acid-based resin, resulting in suppression of bleed-out of the block copolymer plasticizer. Demonstrate great effect. The number average molecular weight of the polylactic acid segment of 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.

  Moreover, although a block copolymer plasticizer has a polyether segment, it is more preferable to have the segment which consists of polyalkylene ether as a polyether segment from a viewpoint which can provide a desired softness | flexibility by addition of a small quantity. Specifically, examples of the polyether segment include segments made of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol / polypropylene glycol copolymer, and the like. Particularly, the segment made of polyethylene glycol is a polylactic acid resin. It is preferable because it has a high affinity for and is excellent in reforming efficiency, and as a result, desired flexibility can be imparted with 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.

  The number average molecular weight of the polyether segment in one molecule of the block copolymer plasticizer is preferably 7,000 to 20,000. By setting the above range, the composition constituting the polylactic acid-based resin film has sufficient flexibility, and the melt viscosity of the entire composition constituting the film is set to an appropriate level, such as an inflation film forming method. The film forming processability can be stabilized.

  In the block copolymer plasticizer, there is no particular limitation on the order configuration of each of the polyether segment and the polylactic acid segment, but at least one block of the polylactic acid segment is more effectively suppressed from the viewpoint of suppressing bleed out. It is preferably at the end of the block copolymer plasticizer molecule.

  In addition, when three components of a block copolymer type plasticizer and (A) a polylactic acid resin, (C) a transesterification catalyst and / or a transesterification catalyst-derived compound are simultaneously present, a polylactic acid segment of the block copolymer type plasticizer And (A) a polylactic acid-based resin undergoes a transesterification reaction, and the block copolymer plasticizer is easily incorporated into the (A) polylactic acid-based resin, resulting in film flexibility and bleed resistance. Is preferable.

  Next, the case where polyethylene glycol (hereinafter, PEG) having hydroxyl ends at both ends 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 M _PEG ) 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 (where "PLA" 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 contained in this block copolymer plasticizer can be substantially determined by (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 by _{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 substantially calculated by 100 × w _E / (w _L + w _E )%.

It is preferable that the plasticizer contained in the film of this invention is 5-30 mass% in 100 mass% of the whole film. By setting it to 5% by mass or more, the flexibility of the film becomes high, and by setting it to 30% by mass or less, the stiffness when made into a film is strong and the handling property, strength, durability, and bleed-out resistance of the plasticizer are improved. Get higher. The content of the plasticizer is more preferably 7 to 25% by mass in 100% by mass of the entire composition.

(Other resins)
The film of the present invention may contain a thermoplastic resin other than those described above for the purpose of improving various physical properties. As for content, 0.1-50 mass% is preferable in 100 mass% of the whole film, 0.3-40 mass% is more preferable, 0.5-30 mass% is further more preferable.

  Examples of thermoplastic resins include polyacetal, polyethylene, polypropylene, polyamide, poly (meth) acrylate, polyphenylene sulfide, polyether ether ketone, polyester, polysulfone, polyphenylene oxide, polyimide, polyether imide, ethylene / glycidyl methacrylate copolymer , Polyester elastomer, polyamide elastomer, ethylene / propylene terpolymer, ethylene / butene-1 copolymer, thermoplastic starch, starch-containing polymer, and the like.

Examples of improving physical properties by containing thermoplastic resins other than polylactic acid resins include improving the high-temperature rigidity of polylactic acid films by containing poly (meth) acrylate, and polylactic acid films by containing polyester. Impact resistance, toughness improvement, thermoplastic starch, or promotion of biodegradability of polylactic acid-based film by containing a starch-containing polymer. As the polymer containing starch, for example, Novamont's biodegradable resin “Matterby” can be used. Regarding the biodegradation promotion, among the applications in which the film of the present invention is used, it is particularly important in agricultural and forestry applications such as agricultural multi-films and pine worm fumigation sheets.

(Mixing of crystalline polylactic acid resin and amorphous polylactic acid resin)
The polylactic acid resin contained in the film of the present invention is preferably a mixture of a crystalline polylactic acid resin and an amorphous polylactic acid resin. This is because, by using a mixture, the advantages of both crystalline and amorphous polylactic acid resins can be achieved.

  That is, the inclusion of the crystalline polylactic acid resin is suitable for improving the tear propagation resistance, impact resistance, heat resistance, and blocking resistance of the film. In addition, when a block copolymer plasticizer is used as the plasticizer, the crystalline polylactic acid-based resin forms a eutectic with the polylactic acid segment of the block copolymer plasticizer, thereby greatly improving the bleed-out resistance. Demonstrate the effect.

  On the other hand, the inclusion of an amorphous polylactic acid resin is suitable for improving the flexibility and bleed-out resistance of the film. This has an effect of providing an amorphous part in which a component such as a plasticizer can be dispersed.

  The crystalline polylactic acid-based resin used in the film of the present invention has a content ratio of L-lactic acid units in poly-L-lactic acid or D in poly-D-lactic acid from the viewpoint of improving tear resistance and impact resistance. -The content ratio of the lactic acid unit is preferably 96 to 100 mol%, more preferably 98 to 100 mol%, still more preferably 99 to 100 mol%, and particularly preferably 99.5 to 100 mol% in 100 mol% of all lactic acid units. It is.

When the total of the crystalline polylactic acid resin and the amorphous polylactic acid resin in the film of the present invention is 100% by mass, the ratio of the crystalline polylactic acid resin is preferably 5 to 60% by mass. More preferably, it is -50 mass%, and it is further more preferable that it is 20-40%.

(Organic lubricant)
It is preferable that the film of this invention contains 0.1-5 mass% of organic lubricants in 100 mass% of the whole film. 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, 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.

(particle)
Particles may be added to the film of the present invention for the purpose of improving the slipperiness and blocking resistance of the processed product.

  Examples of inorganic 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, wollastonite, potassium titanate, aluminum boride, and zepiolite. Various composite oxides such as, various phosphates such as lithium phosphate, calcium phosphate and magnesium phosphate, various oxides such as aluminum oxide, titanium oxide, zirconium oxide and zinc oxide, water such as aluminum hydroxide and magnesium hydroxide Fine particles made of various salts such as oxide and lithium fluoride can be used.

  These inorganic particles are surface-treated with fatty acids, resin acids, titanate coupling agents, silane coupling agents, phosphate esters, etc. for the purpose of increasing compatibility with the resin and preventing aggregation in the resin. May be applied.

  As the organic particles, fine particles made of calcium oxalate, terephthalate such as calcium, barium, zinc, manganese, magnesium, or the like 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 average particle diameter of both inorganic particles and organic particles is not particularly limited, but is preferably 0.01 to 5 μm, more preferably 0.1 to 4 μm, and most preferably 0.5 to 3 μm.

(High molecular weight agent)
Examples of the high molecular weight agent used in the present invention include polyvalent carboxylic acids, metal complexes, epoxy compounds, isocyanates, or mixtures thereof. As polyvalent carboxylic acids, (anhydrous) phthalic acid, (anhydrous) maleic acid, trimethyladipic acid, trimesic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) 3, 3 ', 4, Examples thereof include 4′-benzophenone tetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, and mixtures thereof. Metal complexes include lithium formate, sodium methoxide, potassium propionate, magnesium ethoxide, calcium propionate, manganese acetylacetonate, cobalt acetylacetonate, zinc acetylacetonate, cobalt acetylacetonate, iron acetylacetonate, aluminum Acetylacetonate, aluminum isopropoxide, tetrabutoxytitanium and the like can be mentioned, and divalent or higher metal complexes are particularly preferable. Examples of the epoxy compound include bisphenol A type diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, terephthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, ο-phthalic acid diglycidyl ester, 3,4-epoxycyclohexylmethyl-3,4 epoxy epoxycyclocarboxylate, bis (3,4 epoxycyclohexyl) adipate, tetradecane-1,14-dicarboxylic acid glycidyl ester, and the like can be used. Isocyanates modified with hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, diisocyanate Polyethers modified with diisocyanates, compounds modified with polyfunctional alcohols with polyfunctional isocyanates, polyethers modified with polyisocyanates, polyesters modified with polyisocyanates, and mixtures thereof.

Among these high molecular weight agents, polycarboxylic acids and metal complexes are preferable from the viewpoint of safety and coloring, and aliphatic compounds are preferable from the viewpoint of biodegradability. The addition amount of the high molecular weight agent varies depending on the type, but generally, 0.001% by mass to 5% by mass, more preferably 0.01% by mass to 2% by mass with respect to 100% by mass of the whole film. % Is preferably added. If it exceeds 5% by mass, the polylactic acid resin or the aliphatic polyester resin and / or the aliphatic aromatic polyester resin excluding the polylactic acid resin may cause gelation, coloring, viscosity reduction, etc. Will increase. Moreover, if it is less than 0.001 mass part, the effect of high molecular weight will become inadequate.

(Additive)
The film 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 antioxidants, crystal nucleating agents, UV stabilizers, anti-coloring agents, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, antioxidants, ion-exchange agents, and tackifying Agents, antifoaming agents, color pigments, dyes and the like.

  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.

Crystal nucleating agents include melamine compounds, phenylphosphonic acid metal salts, benzenecarboxamide derivatives, aliphatic / aromatic carboxylic acid hydrazides, sorbitol compounds, amino acid, polypeptides, organic nucleating agents such as metal phthalocyanines, and talc. Silicate minerals such as clay, mica and kaolinite, and inorganic crystal nucleating agents such as carbon black can be preferably used.

(Elongation at break)
In the film of the present invention, the elongation at break in the length direction and the width direction (direction perpendicular to the length direction) is preferably 150% or more and 700% or less. When the elongation at break is 150% or more, the tear resistance and impact resistance are high, and the agricultural and forestry applications such as agricultural multi-film and pine worm fumigation sheets, garbage bags, compost bags, and various packaging applications It is difficult to break and improves practicality. Further, when the elongation at break is 700% or less, tarmi and wrinkles during roll-to-roll running and winding are less likely to occur, and the roll winding shape and unwinding property are improved. The elongation at break in the length direction and the width direction is more preferably from 200% to 600%, more preferably from 230% to 500%, and even more preferably from 250% to 500%.

Examples of a method for adjusting the elongation at break in the length direction and the width direction to 150 to 700% include polylactic acid resins, aliphatic polyester resins other than polylactic acid resins, and / or aliphatic aromatic polyesters. The method which makes the compounding quantity of a system resin, a transesterification catalyst / or a transesterification catalyst origin compound, and a plasticizer the preferable range mentioned above, respectively is mentioned.

(Elastic modulus)
The film of the present invention preferably has a tensile modulus in the length direction and the width direction of 100 to 1,500 MPa in order to impart sufficient flexibility. The tensile elastic modulus is more preferably 100 to 1,000 MPa, further preferably 100 to 600 MPa, and further preferably 100 to 500 MPa.

Examples of a method for setting the tensile modulus in the length direction and the width direction to 100 to 1,500 MPa include polylactic acid resins, aliphatic polyester resins other than polylactic acid resins, and / or aliphatic aromatic polyester systems. Examples thereof include a method in which the blending amounts of the resin, the transesterification catalyst / and / or the transesterification catalyst-derived compound, and the plasticizer are within the preferable ranges described above.

(Thickness)
The film of the present invention preferably has a film thickness of 5 to 200 μm. By setting the film thickness to 5 μm or more, the firmness of the film becomes strong, the handleability is excellent, and the roll winding shape and unwinding property are good. Flexibility is improved by making the film thickness 200 μm or less, and it is easy to handle when used for agricultural and forestry applications such as agricultural multi-film and pine worm fumigation sheets, garbage bags, compost bags, or various packaging applications. In addition, the bubble is not destabilized by its own weight particularly in the inflation film forming method. As for film thickness, 7-150 micrometers is more preferable, and 10-100 micrometers is further more preferable.

(Tear propagation resistance)
The film of the present invention preferably has a tear propagation resistance of 30 N / mm or more in both the length direction and the width direction. When the tear propagation resistance is 30 N / mm, when it is used for agricultural and forestry applications such as agricultural multi-film and pine worm fumigation sheets, garbage bags, compost bags, or various packaging applications, from the cut surface and holes It becomes difficult for tears to progress. Further, the tear propagation resistance in the length direction and the width direction is more preferably 40 N / mm or more, and further preferably 50 N / mm or more. The upper limit of the tear propagation resistance value does not exist in particular, but since the main component is polylactic acid resin and aliphatic polyester resin and / or aliphatic aromatic polyester resin other than polylactic acid resin, The tear propagation resistance value is estimated to be about 500 N / mm.

Examples of a method for setting the elongation in the length direction and the width direction to 30 N / mm or more include polylactic acid resins, aliphatic polyester resins other than polylactic acid resins, and / or aliphatic aromatic polyester resins. , Transesterification catalyst / and / or transesterification catalyst-derived compound, and a method of setting the blending amount of the plasticizer within the above-mentioned preferred ranges.

(Production method)
Next, the method for producing the film of the present invention will be described in detail, but the production method is not limited to this.

  The polylactic acid resin 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.

  Compositions constituting the film of the present invention, that is, polylactic acid resins, aliphatic polyester resins other than polylactic acid resins and / or aliphatic aromatic polyester resins, plasticizers, or other nucleating agents In obtaining a composition containing components, 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 in which a composition is produced by melt-kneading each component, which is a practical production method that does not require such steps. 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 180 ° C. to 210 ° C. from the viewpoint of preventing the deterioration of the polylactic acid resin.

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

  In producing the film of the present invention, for example, when the composition obtained by the above-described method is once pelletized, melt-kneaded again, and extruded / formed, the pellet is dried at 60 to 100 ° C. for 6 hours or more. For example, it is preferable to use a composition containing a polylactic acid resin or the like having a water content of 1,200 ppm or less, preferably 500 ppm or less, more preferably 200 ppm or less. Furthermore, it is preferable to reduce the lactide content in the composition containing the polylactic acid resin or the like by vacuum drying under a high vacuum with a degree of vacuum of 10 Torr or less. By reducing the water content of the composition containing the polylactic acid resin and the like to 1,200 ppm or less and the lactide content, hydrolysis during melt-kneading can be prevented, thereby preventing a decrease in molecular weight. It is also preferable because the melt viscosity at the time of preparing a composition containing a resin or the like can be set to an appropriate level and the film forming process can be stabilized. From the same point of view, when pelletizing or melt-extrusion / film formation, a twin-screw extruder with a vent hole is used and melt extrusion is performed while removing volatiles such as moisture and low molecular weight substances. It is preferable.

  When the film of the present invention is produced by the inflation method, for example, the composition prepared by the above-described method is melt-extruded by a twin-screw extruder with a vent hole and led to an annular die, and is extruded from the annular die to the inside. Is supplied with dry air and formed into a balloon shape (bubble), air-cooled and solidified uniformly with an air ring, and folded at a predetermined take-up speed while being folded flat with a nip roll. It is only necessary to cut the end and wind up. Then, in order to suppress the heat shrink of a film, you may heat-process in a heating roll or oven.

  In this case, the thickness may be adjusted to 5 to 200 μm depending on the discharge amount from the annular die, the take-up speed of the nip roll, and the bubble blowing ratio. However, from the viewpoint of thickness accuracy and uniformity, the annular die is spiral. It is preferable to use a mold, and from the same viewpoint, it is preferable to use a rotary die.

  Further, the extrusion temperature of the composition constituting the film of the present invention is usually in the range of 150 to 240 ° C., but in order to promote effective crystallization in order to develop good tear resistance and impact resistance, it is cyclic. The temperature of the die is important, and the temperature of the annular die is in the range of 150 to 190 ° C, preferably 155 to 185 ° 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 film of the present invention is excellent in bleed resistance and blocking resistance, when the film is unwound from the film roll after being wound, it can be smoothly unwound.

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) Elongation at break (%)
Stress-strain measurement was performed using TENSILON UCT-100 manufactured by Orientec Co., Ltd. Specifically, a sample is cut into a strip shape having a length of 150 mm and a width of 10 mm in the measurement direction, and measurement is performed 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. went. Moreover, 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, and the average value was evaluated.
(2) Elastic modulus (MPa)
The stress-strain measurement is performed by the method described in (1), and the stress difference between the two points on the straight line is divided by the strain difference between the two points using the first straight line portion of the stress-strain curve. The elastic modulus was calculated. 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, and the average value was evaluated.
(3) Tear propagation resistance (N / mm)
Using a tear propagation resistance meter (Elmendorf) manufactured by Toyo Seiki Seisakusho Co., Ltd., the measurement was performed according to the method defined in JIS K 7128-2 (1998). The sample size was 63 mm in the tear direction × 76 mm in the direction perpendicular to the tear, and 20 mm incision was made in the tear 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, and the average value was evaluated.
(4) Tm1-Tm2 (° C)
Using a differential scanning calorimeter RDC220 manufactured by Seiko Instruments Inc., 5 mg of a film sample is set on an aluminum pan, heated from 25 ° C. to 220 ° C. at a heating rate of 20 ° C./min, and melted at 220 ° C. for 5 minutes. After holding, it was rapidly cooled to 25 ° C. Furthermore, the same temperature raising, melting and holding processes were repeated. Then, Tm1-Tm2 was calculated with Tm as the melting peak temperature derived from the polylactic acid resin in the first temperature raising process and Tm2 as the melting peak temperature derived from the polylactic acid resin in the first temperature raising process.

[(A) Polylactic acid resin]
(4032D)
Poly L-lactic acid, “4032D” manufactured by Natureworks, mass average molecular weight 200,000, D-form content 1.4%, melting point 166 ° C.
(4060D)
Poly L-lactic acid, “4060D” manufactured by Natureworks, mass average molecular weight 200,000, D-form content 12.0%, no melting point.

The mass average molecular weight was measured using Waters 2690 manufactured by Nippon Waters Co., Ltd., using polymethyl methacrylate as a standard, a column temperature of 40 ° C., and a chloroform solvent.

[(B) Aliphatic polyester resin and / or aliphatic aromatic polyester resin excluding polylactic acid resin (referred to as “aliphatic and / or aromatic resin” in the table)]
(Ecoflex)
Polybutylene adipate terephthalate, “Ecoflex C1200” manufactured by BASF.
(GS Pla)
Polybutylene succinate, “GS Pla” manufactured by Mitsubishi Chemical.

[(C) Transesterification catalyst and / or compound derived from transesterification catalyst (indicated as “transesterification catalyst” in the table)]
(Mg acetate)
Magnesium acetate tetrahydrate, manufactured by Nacalai Tesque.
(P-TSA)
p-Toluenesulfonic acid monohydrate, manufactured by Nacalai Tesque.
(Mg stearate)
Made of magnesium stearate, Nacalai Tesque.
(Pyridine)
Made of pyridine and Nacalai Tesque.
(Mg chloride)
Magnesium chloride hexahydrate, manufactured by Wako Pure Chemical Industries.
(Li fluoride)
Lithium fluoride, manufactured by Wako Pure Chemical Industries.
(Zn propionate)
Zinc propionate, manufactured by Wako Pure Chemical Industries.
(Mg_MB acetate)
13 parts by mass of polylactic acid resin (4032D), 34 parts by mass of polylactic acid resin (4060D), 30 parts by mass of aliphatic polyester resin and / or aliphatic aromatic polyester resin (Ecoflex) excluding polylactic acid resin, A mixture of 0.5 parts by mass of a transesterification catalyst (Mg acetate), 19 parts by mass of a plasticizer (PLA-PEG), 1 part by mass of an organic lubricant (S-10) and ₃ parts by mass of particles (CaCO ₃ ) has a cylinder temperature of 190 ° C. Was used in a twin screw extruder with a vacuum diameter of 44 mm and melt-kneaded while degassing the vacuum vent, homogenized, and pelletized to obtain a composition.

The pellets of this composition were vacuum-dried at a temperature of 60 ° C. for 12 hours using a rotary drum type vacuum dryer to obtain a master batch of a transesterification catalyst (Mg_MB acetate).
(Mg_MB chloride)
13 parts by mass of polylactic acid resin (4032D), 34 parts by mass of polylactic acid resin (4060D), 30 parts by mass of aliphatic polyester resin and / or aliphatic aromatic polyester resin (Ecoflex) excluding polylactic acid resin, A mixture of 0.5 parts by mass of a transesterification catalyst (Mg chloride), 19 parts by mass of a plasticizer (PLA-PEG), 1 part by mass of an organic lubricant (S-10) and ₃ parts by mass of particles (CaCO ₃ ) was added at a cylinder temperature of 190 ° C. Was used in a twin screw extruder with a vacuum diameter of 44 mm and melt-kneaded while degassing the vacuum vent, homogenized, and pelletized to obtain a composition.

The pellets of this composition were vacuum-dried at a temperature of 60 ° C. for 12 hours using a rotary drum type vacuum dryer to obtain a master batch of a transesterification catalyst (MgCl_MB).

[(E) Plasticizer]
(PLA-PEG)
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. Thus, a plasticizer E1 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.
(PEG)
Polyethylene glycol, “PEG-6000S” manufactured by Sanyo Chemical Industries.

[Organic lubricant]
(S-10)
"Alflow S-10" made of stearamide, NOF.

[particle]
(CaCO ₃ )
“Cartex R” made of calcium carbonate, Maruo calcium, average particle size 2.8 μm.

[Phosphorus compounds]
(phosphoric acid)
Made of phosphoric acid, Nacalai Tesque.

[Production of polylactic acid film]
(Example 1)
13 parts by mass of polylactic acid resin (4032D), 34 parts by mass of polylactic acid resin (4060D), 30 parts by mass of aliphatic polyester resin and / or aliphatic aromatic polyester resin (Ecoflex) excluding polylactic acid resin, A mixture of 0.3 parts by mass of a transesterification catalyst (Mg acetate), 19 parts by mass of a plasticizer (PLA-PEG), 1 part by mass of an organic lubricant (S-10), and ₃ parts by mass of particles (CaCO ₃ ) was used at a cylinder temperature of 190 ° C. Was used in a twin screw extruder with a vacuum diameter of 44 mm and melt-kneaded while degassing the vacuum vent, homogenized, and pelletized to obtain a composition.

The pellet of this composition was vacuum-dried at a temperature of 60 ° C. for 12 hours using a rotary drum type vacuum dryer. 100 parts by mass of the pellet of this composition and 1 part by mass of a phosphorus compound (phosphoric acid) were mixed, Finally, the composition shown in Table 1 was supplied to a single screw extruder with a screw diameter of 65 mm at an extruder cylinder temperature of 190 ° C., and a spiral annular die (Labtech Engineering) with a diameter of 250 mm, a lip clearance of 1.3 mm, and a temperature of 155 ° C. Manufactured), extruded in a bubble shape with a blow ratio of 3.4, air-cooled with a cooling ring, taken up at 22 m / min while being folded with a nip roll above the die, and cut at both ends with an edge cutter. The film was wound up with a winder at a tension of 5.5 kgf. A film having a final thickness of 18 μm was obtained by adjusting the discharge amount. Table 1 shows the physical properties of the obtained film.

  In Examples 2 to 10 and Comparative Examples 1 to 5, films were obtained in the same manner as in Example 1 except that the film compositions were changed as shown in Tables 1 and 2.

  In addition, Examples 11 to 17 and Comparative Examples 6 to 8 were used except that the spiral annular dies were changed to those manufactured by Plastic Engineering Laboratory, and the composition of the film was changed as shown in Table 3. A film was obtained in the same manner as in 1.

  The physical properties of the obtained film are shown in Tables 1 to 3.

In addition, about the film of Example 7, although the physical property immediately after film forming was as having described in Table 1, there existed a tendency for tear propagation resistance to fall with progress of time.

  The film of the present invention is a film containing a polylactic acid resin excellent in flexibility and tear propagation resistance, and an aliphatic polyester resin and / or an aliphatic aromatic polyester resin excluding the polylactic acid resin. The film of the present invention is required to have high flexibility and high tear propagation resistance, agricultural and forestry applications such as agricultural multi-films and pine fumigation sheets, garbage bags and compost bags, and food products such as vegetables and fruits It can be preferably used for various packaging applications such as bags for industrial use and bags for various industrial products.

Claims (9)

  (A) polylactic acid resin, (B) aliphatic polyester resin and / or aliphatic aromatic polyester resin excluding polylactic acid resin, and (C) transesterification catalyst and / or transesterification catalyst-derived compound Contains film.   (C) The film of Claim 1 whose transesterification catalyst is a metal salt or a sulfur acid.   (C) The transesterification catalyst is a metal salt of an organic acid having an alkyl group having 0 to 5 carbon atoms, a halogenated metal salt, or a sulfur acid having an alkyl group having 0 to 5 carbon atoms. The film according to claim 2.   (D) A block copolymer having a polylactic acid segment and an aliphatic polyester segment excluding polylactic acid, and / or a block copolymer having a polylactic acid segment and an aliphatic aromatic polyester segment. The film in any one of 1-3. In DSC measurement, the melting peak temperature derived from (A) polylactic acid resin in the first temperature raising process is Tm, and the melting peak temperature derived from (A) polylactic acid resin in the first temperature raising process is Tm2. When doing, the film in any one of Claims 1-4 which has the following relationship.
0.1 ≦ Tm1-Tm2 ≦ 1   (A) The film in any one of Claims 1-5 obtained by adding 0.01 mass part or more and 10 mass parts or less of phosphorus compounds with respect to 100 mass parts of polylactic acid-type resin.   (E) The film in any one of Claims 1-6 containing a plasticizer.   The film according to claim 7, wherein (E) the plasticizer is a block copolymer having a polylactic acid segment and a polyether segment.   (B) Polybutylene adipate terephthalate is contained as the aliphatic aromatic polyester resin in the aliphatic polyester resin and / or the aliphatic aromatic polyester resin excluding the polylactic acid resin. The film of crab.