JP2011252062A - Resin composition and molded article using the resin composition, film, oriented film, heat-shrinkable film, heat-shrinkable label, and container mounting the label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polylactic acid-based resin composition excellent in shock resistance and transparency, a polylactic acid-based film, a molded article using the film, an oriented film, a heat-shrinkable film, and a container mounting the film.SOLUTION: The resin composition comprises a polylactic acid-based resin (A), a polyolefin resin (B) and polyether/polyolefin copolymer (C), in which with respect to 100 mass% of the sum of the polylactic acid-based resin (A) and the polyolefin resin (B), the polylactic acid-based resin (A) is included by 30 mass% or more and 90 mass% or less and the polyolefin resin (B) is included by 10 mass% or more and 70 mass% or less, and the polyether/polyolefin copolymer (C) is included by 1 part by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the sum of the polylactic acid-based resin (A) and the polyolefin resin (B).

Description

  The present invention relates to a resin composition comprising a polylactic acid-based resin, a polyolefin-based resin, and a polyether / polyolefin-based copolymer, and a molded article, film, stretched film, and heat-shrinkable film comprising the resin composition as a main component. The present invention relates to a heat-shrinkable label and a container equipped with the label.

Synthetic resins made from petroleum are widely used because of their excellent characteristics and low cost, but they are low in degradability in the natural environment, generate large amounts of heat during incineration, and emit large amounts of CO ₂ gas. In recent years, research and development of biodegradable polymers that can be decomposed by microorganisms existing in soil and water have been widely conducted from the viewpoint of protecting the natural environment.

  Among these biodegradable polymers, polylactic acid is known as a polymer that can be melt-molded. Since polylactic acid has excellent physical properties such as heat resistance and high strength, it has been studied in various fields such as films, sheets and fibers. In addition, for the purpose of imparting impact resistance to the hard and brittle characteristics of polylactic acid, studies have been widely conducted on materials in which polylactic acid is mixed with polyolefin.

  For example, a resin composition having an excellent balance between hardness and impact resistance by mixing polylactic acid (Pla) and olefin elastomer (Oep) in a mass ratio of Pla / Oep = 90 / 10-60 / 40. An article and a molded body are disclosed in Patent Document 1. This molded body improves the impact resistance of polylactic acid by mixing polylactic acid with ethylene-propylene rubber, ethylene-octene rubber, or ethylene-butadiene rubber as an olefin-based elastomer. However, Patent Document 1 does not describe the relationship between the crystallinity of the olefin-based elastomer used and the transparency of the resulting resin composition or molded article. In addition, since the compatibility between the polylactic acid used and the olefin-based elastomer is poor, it is difficult to obtain a resin composition and a molded article described in Patent Document 1 that have both excellent impact resistance and transparency. Met.

  Further, Patent Document 2 discloses a naturally decomposable resin composition in which 99 to 85% by mass of an aliphatic polyester mainly composed of lactic acid and 1 to 15% by mass of syndiotactic polypropylene (SPP) are mixed. Yes. It is described that the SPP contained in this resin composition has lower crystallinity than conventional isotactic polypropylene, can maintain transparency due to its characteristics, and can impart flexibility and impact resistance of polyolefin. ing. However, SPP is a special polypropylene, and it still has high crystallinity and is excellent in both impact resistance and transparency in order to give sufficient impact resistance to aliphatic polyesters mainly composed of lactic acid. It was difficult to obtain a resin composition.

  Further, Patent Document 3 discloses a resin composition obtained by blending a compatibilizer with a polylactic acid resin and a polyolefin resin. However, when the compatibilizing agent described in the above patent document is used, although the affinity between the polylactic acid resin and the polyolefin resin is improved, the average particle diameter of the dispersed phase in the phase structure of the resin composition Is large and is insufficient as an impact resistance improving effect.

  On the other hand, Patent Documents 4 and 5 disclose antistatic resin compositions comprising a polyolefin, a block polymer of a hydrophilic polymer, and a thermoplastic resin. These patent documents relate to an invention whose main purpose is to impart antistatic properties to a thermoplastic resin composition, and although there is knowledge about the affinity of polyolefin and hydrophilic polymer block polymers with polyolefin, It does not disclose that it plays a role as a compatibilizing agent for improving the compatibility between polylactic acid-based resins and polyolefin-based resins, and obtains a resin composition having excellent characteristics of both impact resistance and transparency. No solution has been suggested.

JP 2006-152162 A JP-A-10-251498 JP 2008-38142 A JP 2001-278985 A JP 2003-48990 A

  The present invention has been made in view of the above-mentioned problems of the prior art, and the problem of the present invention is that it has an excellent appearance and resistance, comprising a polylactic acid resin, a polyolefin resin, and a polyether / polyolefin copolymer. A resin composition having impact properties and transparency, a film comprising the resin composition, a molded article using the film, a stretched film, a heat shrinkable film, a heat shrinkable label, and the heat shrinkable label It is to provide a mounted container.

  As a result of extensive studies, the present inventor selected a polyether / polyolefin copolymer as a compatibilizing agent for improving the affinity between the polylactic acid resin and the polyolefin resin, Discovered that molded products and films obtained from a resin composition mixed with polyolefin resin at a predetermined ratio are molded products and films having excellent appearance, impact resistance, and transparency, and completed the present invention. It came to do.

That is, an object of the present invention is a resin composition comprising a polylactic acid resin (A), a polyolefin resin (B), and a polyether / polyolefin copolymer (C), wherein the polylactic acid resin When the total of (A) and the polyolefin resin (B) is 100 mass%, the polylactic acid resin (A) is 30 mass% or more and 90 mass% or less, and the polyolefin resin (B) is 10 mass% or more. 70 parts by mass or less and 1 part by mass or more and 25 parts by mass or less of the polyether / polyolefin copolymer (C) with respect to a total of 100 parts by mass of the polylactic acid resin (A) and the polyolefin resin (B). A resin composition comprising a polylactic acid resin (A), a polyolefin resin (B), and a polyether / polyolefin copolymer (C). When the total of all components of the resin composition is 100% by mass, the polylactic acid component is 24% by mass to 90% by mass, the polyolefin component is 8% by mass to 72% by mass, and the polyether component Is solved by a resin composition of 0.2 mass% or more and 10 mass% or less.

  Another object of the present invention is to provide a molded product comprising the above resin composition as a main component, a film having an internal haze of 0.40% or less per 1 μm thickness, and a stretch formed by stretching the film in at least one direction. Film, heat-shrinkable film having a heat shrinkage ratio of 20% or more when immersed in warm water at 80 ° C. for 10 seconds, a label using this heat-shrinkable film as a base material, and this label were attached It is also solved by the container.

  Since the present invention is a resin composition comprising a polylactic acid resin (A), a polyolefin resin (B), and a polyether / polyolefin copolymer (C), according to the present invention, an excellent appearance, A resin composition having impact resistance and transparency can be provided.

  In particular, since the resin composition of the present invention uses a polyolefin resin (B) having a crystallization heat amount ΔHc of 40 J / g or less, the polylactic acid resin (A) and the refractive index are reduced, and excellent transparency is achieved. Can be obtained.

  Furthermore, according to the present invention, it is possible to provide a molded article, a film, a stretched film, a heat-shrinkable label, and a container equipped with the label that have excellent appearance, transparency, and impact resistance.

It is a TEM photograph of a preferred embodiment of the present invention (part 1).

It is a TEM photograph of a preferred embodiment of the present invention (part 2).

It is a TEM photograph of a preferred embodiment of the present invention (part 3).

It is a TEM photograph of the comparison mode of the present invention (the 1).

It is a TEM photograph of the comparison mode of the present invention (the 2).

  Hereinafter, a resin composition comprising a polylactic acid resin (A), a polyolefin resin (B), and a polyether / polyolefin copolymer (C) as an example of an embodiment of the present invention, this resin composition The molded article, film, stretched film, heat-shrinkable film, heat-shrinkable label, and container equipped with this label will be described in detail.

  In the present specification, the main component is a component contained in the largest amount, and is usually 50% by mass or more, preferably 80% by mass or more and 100% by mass when the total mass is 100% by mass. The component contained with the content rate of% or less. “Film” refers to a thin flat product that is extremely small compared to its length and width and whose maximum thickness is arbitrarily limited, and is usually provided in the form of a roll ( The Japanese Industrial Standard (JISK6900) and “sheet” refer to a product that is thin by definition in the Japanese Industrial Standard (JIS), and usually has a thickness that is small instead of length and width. However, the boundary between the sheet and the film is not clear, and it is not necessary to distinguish both in terms of the wording in the present invention. Therefore, in the present invention, the term “film” includes “sheet”.

[Resin composition]
The resin composition of the present invention contains a polylactic acid resin (A), a polyolefin resin (B), and a polyether / polyolefin copolymer (C) as main components.

<Polylactic acid resin (A)>
As the polylactic acid resin (A) usable in the present invention, a copolymer (poly (DL-lactic acid)) whose structural units are L-lactic acid and D-lactic acid, and a mixture of these copolymers are preferably used. be able to. When the polylactic acid resin (A) is a mixture of D-lactic acid and L-lactic acid, the mixing ratio of D-lactic acid and L-lactic acid is D-lactic acid: L-lactic acid = 99.8: 0. It is preferably 2 to 75:25 or D-lactic acid: L-lactic acid = 0.2: 99.8 to 25:75, and D-lactic acid: L-lactic acid = 99.5: 0.5. Or more preferably 80:20 or D-lactic acid: L-lactic acid = 0.5: 99.5 to 20:80.

  Polylactic acid composed of D-lactic acid alone or L-lactic acid alone exhibits very high crystallinity, has a high melting point, and tends to be excellent in heat resistance and mechanical properties. However, for example, when used as a film, the manufacturing process includes printing and a processing process using a solvent, so that the crystallinity of the constituent material itself is moderately lowered for the purpose of improving printability and solvent sealing properties. It will be necessary. Moreover, when crystallinity is too high, orientation crystallization advances at the time of extending | stretching, and there exists a tendency for shrinkage | contraction characteristic to fall. Therefore, it is desirable to appropriately select the mixing ratio of D-lactic acid and L-lactic acid according to the use of a film or the like.

  In the present invention, the polylactic acid resin (A) can also use D-lactic acid and L-lactic acid having different copolymerization ratios. In that case, what is necessary is just to make it the value which averaged the copolymerization ratio of D-lactic acid and L-lactic acid of a some lactic acid type polymer in the said range. To balance the heat resistance and transparency by mixing two or more polylactic acid resins with different copolymer ratios of D-lactic acid and L-lactic acid, and adjusting the crystallinity. Can do.

  The polylactic acid resin (A) used in the present invention may be a copolymer of lactic acid and α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid. Here, the “α-hydroxycarboxylic acid” copolymerized with the lactic acid resin includes optical isomers of lactic acid (D-lactic acid for L-lactic acid, and L-lactic acid for D-lactic acid, respectively). Glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methylbutyric acid, 2-hydroxy Bifunctional aliphatic hydroxy-carboxylic acids such as caprolactone and lactones such as caprolactone, butyl lactone and valerolactone. Examples of the “aliphatic diol” copolymerized with the lactic acid resin include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Examples of the “aliphatic dicarboxylic acid” to be copolymerized include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid. The copolymerization ratio of the copolymer of lactic acid and α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid is such that lactic acid / α-hydroxycarboxylic acid, lactic acid / aliphatic diol, or lactic acid / aliphatic dicarboxylic acid. It is preferably in the range of 90/10 to 10/90, more preferably in the range of 80/20 to 20/80, and still more preferably in the range of 70/30 to 30/70. When the copolymerization ratio is within the above range, a resin composition having a good balance of physical properties such as rigidity, transparency and impact resistance can be obtained.

  The polylactic acid resin (A) used in the present invention can be produced by a known polymerization method such as a condensation polymerization method or a ring-opening polymerization method. For example, in the case of a condensation polymerization method, a polylactic acid resin having an arbitrary composition can be obtained by directly dehydrating condensation polymerization of D-lactic acid, L-lactic acid, or a mixture thereof. Further, in the ring-opening polymerization method, a lactide which is a cyclic dimer of lactic acid is subjected to ring-opening polymerization in the presence of a predetermined catalyst while using a polymerization regulator or the like, if necessary. A lactic acid resin can be obtained. The lactide includes DL-lactide, which is a dimer of L-lactic acid. By mixing and polymerizing these as necessary, a polylactic acid resin having an arbitrary composition and crystallinity can be obtained. it can. Furthermore, a small amount of chain extender such as a diisocyanate compound, diepoxy compound, acid anhydride, acid chloride, etc. may be used for the purpose of increasing the molecular weight.

  The weight (mass) average molecular weight of the polylactic acid resin (A) used in the present invention is 20,000 or more, preferably 40,000 or more, more preferably 60,000 or more, and the upper limit is 400,000 or less. Preferably it is 350,000 or less, More preferably, it is 300,000 or less. Weight (mass) If the average molecular weight is 20,000 or more, an appropriate resin cohesive force can be obtained, and it is possible to suppress the lack of strong elongation or embrittlement when molded into a film or the like. On the other hand, when the weight (mass) average molecular weight is 400,000 or less, the melt viscosity can be lowered, which is preferable from the viewpoint of production of films and the like and improvement of productivity.

  As a commercial item of the said polylactic acid-type resin (A), "Nature Works (made by Cargill)" etc. are mentioned, for example.

  In order to improve impact resistance, it is possible to add a rubber component other than the polylactic acid resin (A) to the polylactic acid resin (A) within a range that does not impair transparency and impact resistance. preferable. The rubber component is not particularly limited, but is an aliphatic polyester other than the polylactic acid resin (A), an aromatic-aliphatic polyester, a copolymer of a diol, a dicarboxylic acid, and a lactic acid resin, or a core-shell structure rubber. , And ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene- (meth) acrylic acid copolymer (EMA), An ethylene-methyl (meth) acrylic acid copolymer (EMMA) etc. can be used conveniently.

  As the aliphatic polyester obtained by condensing an aliphatic diol and an aliphatic dicarboxylic acid, one or two or more kinds of aliphatic polyesters and aliphatic dicarboxylic acids described below are condensed or condensed, Alternatively, a polymer obtained as a desired polymer by jumping up the molecular weight with an isocyanate compound or the like as required can be mentioned. Here, examples of the aliphatic diol include ethylene glycol, propylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, and suberin. Examples include acid, sebacic acid, dodecanedioic acid and the like.

  In addition, examples of the aliphatic polyester obtained by ring-opening condensation of cyclic lactones include ring-opening polymers such as ε-caprolactone, σ-valerolactone, and β-methyl-σ-valerolactone, which are cyclic monomers. These cyclic monomers can be copolymerized by selecting not only one kind but also plural kinds.

  Examples of synthetic aliphatic polyesters include copolymers of cyclic acid anhydrides and oxiranes, such as copolymers of succinic anhydride and ethylene oxide, copolymers of propion oxide, and the like. it can.

  As a typical aliphatic polyester other than these polylactic acid-based resins, “Bionore” (manufactured by Showa Polymer Co., Ltd.) obtained by polymerizing succinic acid, 1,4-butanediol and adipic acid is commercially available. Can be obtained. Moreover, as a thing obtained by ring-opening condensation of (epsilon) -caprolactone, "Cell Green" (made by Daicel Chemical Industries Ltd.) is mentioned.

  Next, as the aromatic-aliphatic polyester, those having crystallinity lowered by introducing an aromatic ring between the aliphatic chains can be used. The aromatic-aliphatic polyester is obtained, for example, by condensing an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol.

  Here, examples of the aromatic dicarboxylic acid include isophthalic acid, terephthalic acid, and 2,6-naphthalenedicarboxylic acid, and terephthalic acid is most preferably used. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and adipic acid is most preferably used. Two or more types of aromatic dicarboxylic acids, aliphatic dicarboxylic acids or aliphatic diols may be used.

  Typical examples of the aromatic aliphatic polyester include a copolymer of tetramethylene adipate and terephthalate, a copolymer of polybutylene adipate and terephthalate, and the like. EsterBio (manufactured by Eastman Chemicals) as a copolymer of tetramethylene adipate and terephthalate, and Ecoflex (manufactured by BASF) as a copolymer of polybutylene adipate and terephthalate are commercially available.

  Examples of the structure of the polylactic acid resin, diol and dicarboxylic acid copolymer include random copolymers, block copolymers, and graft copolymers, and any structure may be used. However, a block copolymer or a graft copolymer is preferable from the viewpoint of impact resistance and transparency of the film. A specific example is “GS-Pla” (manufactured by Mitsubishi Chemical Corporation).

  The production method of the copolymer of polylactic acid resin, diol and dicarboxylic acid is not particularly limited, but polyester or polyether polyol having a structure obtained by dehydration condensation of diol and dicarboxylic acid is converted to lactide and ring-opening polymerization or transesterification. The method obtained by letting it be mentioned. Further, there is a method in which a polyester or polyether polyol having a structure obtained by dehydration condensation of a diol and a dicarboxylic acid is obtained by dehydration / deglycolization condensation or transesterification with a polylactic acid resin.

  The copolymer of polylactic acid resin, diol and dicarboxylic acid can be adjusted to a predetermined molecular weight using an isocyanate compound or a carboxylic acid anhydride. However, from the viewpoint of workability and mechanical properties, the weight (mass) average molecular weight is 50,000 or more, preferably 100,000 or more, and 300,000 or less, preferably 250,000 or less.

<Polyolefin resin (B)>
It is important that the polyolefin resin (B) used in the present invention has a crystallization heat amount ΔHc of 40 J / g or less from the viewpoint of transparency. The average refractive index of a polyolefin resin is influenced by its crystallinity, and the average refractive index tends to decrease as the polyolefin resin has a lower crystallization heat amount ΔHc. In the present invention, a polyolefin resin (B) having a low crystallization heat amount compared to a general polyolefin resin (a crystallization heat amount ΔHc> 40 J / g, usually in a range from about 60 J / g to about 100 J / g). By using this, the difference in refractive index from the polylactic acid resin (A) can be reduced, and excellent transparency can be maintained. From the viewpoint of further improving the transparency, the heat of crystallization of the polyolefin resin (B) is preferably 30 J / g or less, more preferably 25 J / g or less, and even more preferably 20 J / g or less. . A non-crystalline polyolefin-based resin that does not express the amount of crystallization heat can also be suitably used.
The crystallization heat quantity ΔHc can be measured using a differential scanning calorimeter. Specifically, after heating up to 200 ° C. at a heating rate of 10 ° C./min and holding at 200 ° C. for 5 minutes, It can be expressed as the amount of heat when the temperature is lowered to room temperature at a cooling rate of 10 ° C./min.

  As the polyolefin resin (B), a polyethylene resin, a polypropylene resin, or a mixture thereof having a crystallization calorific value ΔHc in the above range is used from the viewpoints of mechanical properties and moldability of impact resistance and transparency. It is preferable.

  In the case of a polyolefin-based resin, as a means for setting the crystallization heat amount ΔHc in the above range, a method of using an olefin as a copolymer, a method of reducing stereoregularity, or the like is preferably used. Here, as the polyolefin copolymer, for example, a propylene-α-olefin copolymer or an ethylene-α-olefin copolymer is preferably used. The α-olefin of the copolymer is preferably one having 2 to 20 carbon atoms, and is ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene. Etc. can be illustrated. In the present invention, the content of α-olefin in the copolymer is preferably 5% by mass or more, particularly preferably 7% by mass or more and 30% by mass or less from the viewpoint of crystallization heat amount, impact resistance, transparency, and the like. Used. Moreover, you may use the alpha olefin to copolymerize individually by 1 type or in combination of 2 or more types. Moreover, as a method of reducing the stereoregularity of polyolefin resin, the polymerization method of polyolefin resin mentioned later and the method of selecting a polymerization catalyst suitably can be mentioned.

  In the present invention, a propylene-ethylene random copolymer is suitable as the polyolefin resin (B) because of its low crystallinity, balance between impact resistance and heat resistance, and industrial availability at a relatively low cost. Used for.

  Further, the melt flow rate (MFR) of the polyolefin resin (B) is not particularly limited, but usually MFR (JISK7210, temperature: 230 ° C., load: 21.2 N) is 0.5 g / 10 minutes or more, preferably 1.0 g / 10 minutes or more, 15 g / 10 minutes or less, preferably 10 g / 10 minutes or less is used. Here, considering the kneadability, it is preferable to select a material having a viscosity close to that of the polylactic acid resin (A).

  The method for producing the polyolefin resin (B) is not particularly limited as long as the crystallization heat amount ΔHc can be 40 J / g or less, and a known polymerization method using a known olefin polymerization catalyst, for example, Slurry polymerization method, solution polymerization method, bulk polymerization method, gas phase polymerization method, etc. using a multi-site catalyst typified by a Ziegler-Natta type catalyst and a single site catalyst typified by a metallocene catalyst, and a radical initiator And a bulk polymerization method using.

  Specific examples of commercially available products of the polyolefin resin (B) include, for example, “Versify”, “Engage”, “Infuse” (manufactured by Dow Chemical), “Tuffmer” (manufactured by Mitsui Chemicals), “Esprene”. (Manufactured by Sumitomo Chemical Co., Ltd.) and the like.

<Polyether / Polyolefin Copolymer (C)>
The polyether / polyolefin copolymer (C) used in the present invention has a structure in which a polyether block and a polyolefin block are bonded via a chemical bond or alternately and repeatedly. In the polyether / polyolefin copolymer (C), the polyether block part or the polyolefin block part may have a branched structure.

  The polyether block in the polyether / polyolefin copolymer (C) is mainly preferably an alkylene oxide, specifically, an alkylene oxide having 2 to 4 carbon atoms (ethylene oxide, propylene oxide, 1,2-, 1, 4-, 2,3- or 1,3-butylene oxide and a combination of two or more thereof) can be used. The above polyether block may contain other alkylene oxide or substituted alkylene oxide (hereinafter collectively referred to as alkylene oxide), for example, α-olefin having 5 to 12 carbon atoms, styrene oxide, epihalohydrin as necessary. (Such as epichlorohydrin) can be used in a small proportion (for example, 30% or less based on the weight of the total alkylene oxide). When two or more kinds of alkylene oxides are used in combination, the bond form may be random and / or block, and may have a branched structure. Especially, it is preferable that a polyether block is mainly comprised from a polyethylene oxide from a compatible viewpoint with a polylactic acid-type resin (A).

  As the polyolefin block in the polyether / polyolefin copolymer (C), one or a mixture of two or more olefins having 2 to 30 carbon atoms (preferably olefins having 2 to 12 carbon atoms, particularly preferably propylene and And / or ethylene) and high molecular weight polyolefins (olefins having 2 to 30 carbon atoms, preferably polyolefins obtained by polymerizing olefins having 2 to 12 carbon atoms, particularly preferably polypropylene and / or polyethylene). Low molecular weight polyolefin obtained by the thermal degradation method, and the like. A modified group such as carbonyl group, carboxyl group, hydroxyl group, amino group, α, β unsaturated carboxylic acid (anhydride) is added to the molecular chain terminal of the polyolefin block. You may have.

  The ratio of the polyether segment to the polyolefin segment in the polyether / polyolefin copolymer (C) is determined based on the compatibility between the polylactic acid resin (A) and the polyolefin resin (B). Based on the mass of the copolymer (C), the range of polyether segment / polyolefin segment = 20/80 to 80/20 is preferable, and the range of 30/70 to 70/30 is more preferable.

  As a commercial item of the said polyether / polyolefin-type copolymer (C), "Pelestat" (made by Sanyo Chemical Industries) etc. are mentioned, for example.

  The contents of the polylactic acid resin (A), the polyolefin resin (B), and the polyether / polyolefin copolymer (C) in the resin composition of the present invention are as follows: the polylactic acid resin (A) and the polyolefin resin When the total with the resin (B) is 100% by mass, the polylactic acid resin (A) is 30% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, and 90% by mass or less. Preferably it is 80 mass% or less. Further, the polyolefin resin (B) is 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, 70% by mass or less, preferably 50% by mass or less, more preferably 40% by mass. It is as follows. If the content of the polylactic acid resin (A) is 30% by mass or more and the content of the polyolefin resin (B) is 70% by mass or less, the resin composition and film of the present invention have sufficient hardness and heat resistance. Can be given. In addition, if the content of the polylactic acid resin (A) is 90% by mass or less and the content of the polyolefin resin (B) is 10% by mass or more, the resin composition or molded body of the present invention has a polyolefin resin. The impact resistance which is the characteristic of (B) can be provided.

  The content of the polyether / polyolefin copolymer is 1 part by mass or more, preferably 2.5 parts by mass when the total of the polylactic acid resin (A) and the polyolefin resin (B) is 100 parts by mass. As mentioned above, More preferably, it is 5 mass parts or more, 25 mass parts or less, Preferably it is 23.75 mass parts or less, More preferably, it is the range of 22.5 mass parts or less. If the content of the polyether / polyolefin copolymer is 1 part by mass or more, the compatibility effect of the polylactic acid resin (A) and the polyolefin resin (B) can be exhibited, and 25 parts by mass. If it is below, sufficient rigidity (hardness, waist strength) can be imparted to the molded article and film using the resin composition.

  In the resin composition of the present invention, when the total of all components of the resin composition is 100% by mass, in the case of a polylactic acid component, it is 24% by mass or more, preferably 40% by mass or more, and more preferably 48% by mass. And 90% by mass or less, preferably 80% by mass or less. In the case of a polyolefin component, it is 8% by mass or more, preferably 16% by mass or more, more preferably 24% by mass or more, and 72% by mass or less, preferably 56% by mass or less, more preferably 48% by mass or less. . In the case of a polyether component, it is 0.2% by mass or more, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and 10% by mass or less, preferably 9.5% by mass or less. More preferably, it is 9 mass% or less. If each component of the polylactic acid component, the polyolefin component, and the polyether component is within the above range, sufficient hardness and heat resistance can be imparted to the resin composition, the molded body, etc., and the polylactic acid resin (A) And the polyolefin resin (B) can exhibit a compatibility effect and can impart transparency.

(transparency)
Transparency in polymer blends is said to be affected by the particle size of the dispersed phase and the difference in average refractive index between the dispersed phase and the matrix phase. When the particle size of the dispersed phase is smaller than the visible light region, the resin composition exhibits excellent transparency. On the other hand, when the particle size of the dispersed phase is larger than the visible light region, the transparency is better as the difference in average refractive index between the dispersed phase and the matrix phase is smaller. Polylactic acid resins and polyolefin resins are generally poorly compatible and have a large dispersed particle size, so the transparency of resin compositions and molded products obtained from polylactic acid resins and polyolefin resins is both components. It is greatly influenced by the difference in average refractive index.

  The transparency of a molded article comprising a polylactic acid resin and a polyolefin resin, particularly a film, is greatly affected by the average refractive index of the polylactic acid resin and the polyolefin resin used from the above viewpoint. The average refractive index of polylactic acid resin is in the range of about 1.45 to 1.46, and the average refractive index of polyolefin resin is in the range of about 1.50 to 1.51, so the absolute difference Values range from about 0.04 to about 0.06. When this value exceeds 0.04, the resulting film tends to become cloudy.

  On the other hand, since the polyolefin resin (B) used in the present invention is a low-crystalline resin having a crystallization heat amount ΔHc value of 40 J / g or less, the average refractive index is 1.47 to 1. The range is up to about 49, and the difference in average refractive index from the polylactic acid resin (A) can be reduced. If the absolute value of the average refractive index difference between the polylactic acid resin (A) and the polyolefin resin (B) is 0.04 or less, a resin composition and a film excellent in transparency can be obtained, preferably 0.03 or less. In order to further improve the transparency, 0.02 or less is preferable.

(Impact resistance)
The phase structure of the resin composition of the present invention is such that either the polylactic acid resin (A) or the polyolefin resin (B) forms a continuous phase and a dispersed phase, but the polyether / polyolefin copolymer (C). Is blended within the range specified in the present invention, the affinity between the polylactic acid resin (A) and the polyolefin resin (B) is dramatically improved, and the average particle size of the dispersed phase is dramatically reduced. It is possible to remarkably improve the flexibility and impact resistance of the resin composition or molded product. In the resin composition of the present invention, the average particle diameter of the dispersed phase is preferably 1 μm or less, more preferably 700 nm or less, and further preferably 500 nm or less from the viewpoint of impact resistance, transparency, and appearance. Preferably, it is 100 nm or less, and most preferably 70 nm or less. The phase structure of the resin composition can be confirmed using a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

  The resin composition of the present invention is for the purpose of improving and adjusting various physical properties, and other resins, modifiers, fillers, plasticizers, lubricants, antistatic agents, ultraviolet rays as long as the effects of the present invention are not significantly impaired. Absorbers, stabilizers, and the like can be added as appropriate. Examples of other resins that can be added include polyester resins other than polylactic acid resins, polyolefin resins, acrylic resins, polycarbonate resins, polystyrene resins, polyoxymethylene resins, polyethylene oxide resins, polyamide resins Examples thereof include resins and polyvinyl chloride resins. Examples of the modifier include crystal nucleating agents, flame retardants, antibacterial agents, fungicides, and crosslinking aids. Examples of the filler include calcium carbonate (limestone), glass, talc, silica, mica, metal powder, metal oxide and the like. Examples of the plasticizer include glycerin diacetomonocaprate, glycerin diacetomonolaurate, and tributyl acetylcitrate. Examples of lubricants include inorganic particles such as silica, talc, and calcium carbonate, inorganic oxides, carbonates, or organic particles such as crosslinked acrylic, crosslinked polyester, crosslinked polystyrene, and silicone. . Further, organic particles having a multilayer structure polymerized in multiple stages can also be used. Also, liquid paraffin, paraffin wax, polyolefin wax, stearic acid, stearic alcohol, stearic acid amide, oleic acid amide, erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, stearic acid metal salt, stearic acid monoglyceride And stearyl stearate, hydrogenated oil, and the like. Examples of antistatic agents include non-ionic antistatic agents such as polyether ester amide antistatic agents, ethylene oxide-epichlorohydrin antistatic agents, polyether ester antistatic agents, and polystyrene sulfonic acid antistatic agents. Anionic antistatic agents such as cation agents, cationic antistatic agents such as quaternary ammonium base-containing acrylate antistatic agents, or conductive fillers such as carbon black and conductive whiskers. Examples of UV absorbers include benzotriazole UV absorbers, triazine UV absorbers, benzophenone UV absorbers, and benzoate UV absorbers. Examples of stabilizers include hindered amine light stabilizers, hindered phenol antioxidants, phosphorus processing heat stabilizers, hydroxylamine processing heat stabilizers, vitamin E processing heat stabilizers, metal deactivators, Sulfur-based heat stabilizers can be mentioned. In addition, the method of mixing these with the polyester resin composition of this invention is not specifically limited.

  The resin composition of the present invention is a high-performance film having both high strength and transparency while having the strength and heat resistance of polylactic acid resin and the flexibility of polyolefin resin. Therefore, it is effective as a use as a material for shrink labels, sheets and the like.

[Molding]
The resin composition of the present invention is produced by various moldings by molding methods such as injection molding, blow molding, extrusion molding, inflation molding, inbro, foamed sheet molding, and vacuum forming after molding, pressure forming, vacuum pressure forming, etc. can do. That is, a molded body formed by injection molding, or a film or sheet formed by extrusion molding, and a molded body processed from these films and sheets, or a hollow body formed by blow molding, and processed from this hollow body. It can be set as the molded object formed.

  In the present invention, it is particularly preferable to adopt an injection molding method, and in addition to a general injection molding method, gas injection molding, injection press molding, and the like can be employed. As an example of injection molding conditions suitable for the resin composition of the present invention, the cylinder temperature is higher than the melting point or flow start temperature of the resin composition, preferably in the range from 170 ° C to 250 ° C, optimally from 170 ° C to 230 ° C. The mold temperature is suitably in the range, and the mold temperature is suitably (melting point−40 ° C.) or less of the resin composition. If the cylinder temperature is too low, the operability becomes unstable or overloading occurs, such as a short circuit in the molded product. Conversely, if the molding temperature is too high, the resin composition decomposes and the resulting molded product Problems such as reduction in strength and coloration are likely to occur, and both may be undesirable.

  The heat resistance of the resin composition of the present invention can be further improved by promoting crystallization during molding. As a method for this purpose, for example, there is a method of promoting crystallization in a mold at the time of injection molding, and in that case, the glass transition temperature of the resin composition is maintained above (melting point−40 ° C.). A method in which the molded product is held for a certain period of time in the mold and then removed from the mold is preferable. Moreover, even if it is a molded article taken out from the mold without taking such a method, crystallization can be promoted by heat treatment again at a glass transition temperature or higher and (melting point −40 ° C.) or lower. it can.

  Specific examples of the molded body of the present invention include PC housing parts and housings, mobile phone housing parts and housings, other OA equipment housing parts, resin parts for electrical appliances such as connectors; bumpers, instrument panels , Console boxes, garnishes, door trims, ceilings, floors, plastic parts for automobiles such as panels around engines, agricultural materials such as containers and cultivation containers, and plastic parts for agricultural machinery; marine products such as floats and processed fishery products containers Resin parts for use; dishes, food containers such as dishes, cups, and spoons; medical resin parts such as syringes and infusion containers; resin parts for housing, civil engineering, and building materials such as drain materials, fences, storage boxes, and distribution boards for construction; Resin parts for greening materials such as flowerbed bricks and flower pots; Resin parts for leisure and miscellaneous goods such as cooler boxes, fan fans and toys; ballpoint pens, rulers, clips, etc. Stationery resin components and the like.

  In addition, the resin composition of the present invention can be formed into an extrusion-molded product such as a film, a sheet or a pipe, or a hollow molded product. Examples thereof include a number of biaxially stretched films, heat-shrinkable films, agricultural multi-films, construction sheets, various blow molded bottles, and the like.

[Film, stretched film and heat-shrinkable film]
The film of the present invention is a resin composition comprising a polylactic acid resin (A), a polyolefin resin (B), and a polyether / polyolefin copolymer (C), the polylactic acid resin (A) and When the total of the polyolefin resin (B) is 100% by mass, the polylactic acid resin (A) is 30% by mass to 90% by mass, and the polyolefin resin (B) is 10% by mass to 70% by mass. And a polyether / polyolefin copolymer (C) in an amount of 1 part by mass to 25 parts by mass with respect to a total of 100 parts by mass of the polylactic acid resin (A) and the polyolefin resin (B). The internal haze converted to a thickness of 1 μm is 0.40% or less.

  The internal haze in the film of the present invention can be measured according to JIS K7105. Since the internal haze depends on the thickness, the internal haze of the film of the present invention is obtained by dividing the measured value by the thickness of the film and converting it per 1 μm thickness. The internal haze of the film of the present invention is important to be 0.40% or less in terms of 1 μm thickness, more preferably 0.35% or less, and still more preferably 0.30% or less. If the internal haze converted to a thickness of 1 μm exceeds 0.4%, the transparency of the film is rapidly lost, resulting in a cloudy film.

  The film of the present invention only needs to have at least one single layer mainly composed of the above resin composition or at least one layer mainly composed of the above resin composition, and the resin constituting the other layers is not particularly limited. . The resin constituting the other layer is preferably a thermoplastic resin, particularly preferably a polylactic acid resin layer, a polyolefin resin layer, or a mixed resin layer thereof.

  The thickness of the film of the present invention is not particularly limited, but is usually 10 μm or more, preferably 30 μm or more, and 500 μm or less, preferably 300 μm or less. Here, if the thickness is 10 μm or more, the handling property of the film is good. On the other hand, if it is 500 μm or less, the transparency and shrinkage workability are excellent, which is economically preferable. If necessary, surface treatment and surface processing such as corona treatment, printing, coating, and vapor deposition, and bag making processing and perforation processing using various solvents and heat sealing can be performed.

  A stretched film and a heat-shrinkable film can be obtained by stretching the film of the present invention in at least one direction. When the film of the present invention is a heat-shrinkable film, the heat shrinkage rate in the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds is 20% or more, preferably 30% or more, more preferably 30% or more. And 75% or less, preferably 70% or less, and more preferably 65% or less. Further, the heat shrinkage rate in the main shrinkage direction when immersed in warm water at 70 ° C. for 10 seconds is 5% or more, preferably 10% or more, more preferably 15% or more, 40% or less, preferably 35% or less. It is desirable to be.

  In addition, the “main shrinkage direction” means a direction having a large thermal contraction rate in the longitudinal direction (longitudinal direction) of the film and the lateral direction (width direction) of the film. A direction corresponding to the outer circumferential direction is meant, and “orthogonal direction” means a direction perpendicular to the main contraction direction.

  The heat shrinkage rate at the above temperature is an index for determining adaptability to a shrinking process in a relatively short time (several seconds to about several tens of seconds) such as for use as a shrinkage label for a PET bottle. For example, the required shrinkage rate required for a heat-shrinkable film applied to the use of shrinkage labels for PET bottles varies depending on the shape, but is generally about 20% to 70%.

  Further, the shrinkage processing machine that is most commonly used industrially for label mounting of PET bottles is generally called a steam shrinker that uses steam as a heating medium for shrinking. Furthermore, the heat-shrinkable film needs to be sufficiently heat-shrinked at a temperature as low as possible from the viewpoint of the influence of heat on the object to be coated. However, in the case of a film that is highly temperature dependent and has an extremely different shrinkage ratio depending on the temperature, parts with different shrinkage behavior are likely to occur due to temperature spots in the steam shrinker, so shrinkage spots, wrinkles, avatars, etc. occur. The shrink-finished appearance tends to be poor. From the viewpoint of including these industrial productivity, if the film has a thermal shrinkage rate within the above range, it can sufficiently adhere to the object to be coated within the shrinkage processing time, and shrinkage spots, wrinkles and avatars will not be generated. It is preferable because a good shrink-finished appearance can be obtained.

  When the film of the present invention is used as a heat-shrinkable label, the shrinkage rate in the orthogonal direction is preferably 10% or less, preferably 5% or less when heated in 80 ° C. warm water for 10 seconds. Is more preferably 3% or less, and when heated in 70 ° C. warm water for 10 seconds, it is preferably 10% or less, more preferably 5% or less, and 3% or less. More preferably it is. If the heat shrinkage rate in the orthogonal direction is 10% or less, the dimensions in the orthogonal direction after shrinkage are shortened, the printed pattern or characters are distorted after shrinkage, or in the case of a square bottle, Troubles such as sink marks are less likely to occur, which is preferable.

  When the film of the present invention is used as a heat-shrinkable film, the tensile elastic modulus in the orthogonal direction of the film is preferably 1,000 MPa or more, preferably 1,100 MPa or more from the viewpoint of rigidity (waist strength). More preferably. Moreover, the upper limit of the tensile elasticity modulus of the heat shrinkable film used normally is about 3,000 MPa, preferably about 2,900 MPa, and more preferably about 2,800 MPa. If the tensile modulus of elasticity in the orthogonal direction of the film is 1,000 MPa or more, the rigidity of the entire film can be increased. Especially when the film thickness is reduced, the film is made in a container such as a plastic bottle. When covering with a labeling machine or the like, it is preferred that problems such as covering at an angle or a decrease in yield due to film folding or the like are unlikely to occur. In addition, it is preferable that the average value of the tensile elasticity modulus about MD and orthogonal direction (TD) of each film is 1,500 Mpa or more, and it is further more preferable that it is 1,700 Mpa or more. The tensile elastic modulus can be measured under the condition of 23 ° C. according to Japanese Industrial Standard JIS K7127.

  Further, the tensile elastic modulus in the film main shrinkage direction is not particularly limited as long as the film has low stiffness, but it is 1,500 MPa or more, preferably 2,000 MPa or more, more preferably 2,500 MPa or more, and the upper limit is 6 1,000 MPa or less, preferably 4,500 MPa or less, more preferably 3,500 MPa or less. By setting the tensile modulus of elasticity in the main shrinkage direction of the film within the above range, it is preferable because the elasticity of the film can be increased in both directions.

  When the film of the present invention is used as a heat-shrinkable film, the natural shrinkage rate is desirably as small as possible. However, it is generally desirable that the heat shrinkable film has a natural shrinkage rate of 1.5% or less, preferably 1.0% or less after being stored at 30 ° C. for 30 days, for example. If the natural shrinkage rate under the above conditions is 1.5% or less, even if the produced film is stored for a long period of time, it can be stably attached to a container or the like, and it is difficult to cause problems in practice.

  When the film of the present invention is used as a heat-shrinkable film, the rupture resistance is evaluated by a tensile rupture elongation, and in a tensile rupture test under a 23 ° C. environment, particularly in a label application, the film take-off (flow) direction (MD ) At 100% or more, preferably 200% or more, and more preferably 300% or more. If the tensile elongation at break in an environment of 23 ° C. is 100% or more, it is difficult to cause problems such as breakage of the film at the time of printing and bag making, which is preferable. Further, even when the tension applied to the film increases as the speed of processes such as printing and bag making increases, it is more preferable that the tensile elongation at break is 200% or more, so that it is difficult to break.

Next, the manufacturing method of the film of this invention is demonstrated.
The method for producing the film of the present invention is not particularly limited, but using a known method such as an extrusion casting method using a T die, a pressing method, a calendar method, an inflation method, and an injection molding method, Usually, it is molded to a thickness of about 5 to 5000 μm.

  In the method for producing a film of the present invention, the polylactic acid resin (A) to be used has a water content of 0.1% by mass or less, preferably 0.05% by mass or less in order to avoid hydrolysis in the extruder. It is important to keep it sufficiently dry. For example, it is necessary to dry at 55 ° C. for 24 hours (vacuum drying). Moreover, the method of performing what is called non-drying extrusion which performs a vacuum vent using the same direction twin-screw extruder or a single screw vent extruder is also mentioned as a suitable method.

  The stretched film and heat-shrinkable film of the present invention can be produced by a known method. The form may be flat or tube-like, but the flat form is preferable from the viewpoint of productivity (a few products can be taken in the width direction of the raw film) and printing on the inner surface. As a method for producing a flat film, for example, a resin is melted using an extruder, extruded from a T die, solidified by cooling with a chilled roll, roll-stretched in the longitudinal direction, and tenter-stretched in the transverse direction. A method of obtaining a film by annealing, cooling, and winding with a winder (corona discharge treatment on the surface when printing is performed) can be exemplified. Moreover, the method of cutting open the film manufactured by the tubular method and making it flat is also applicable. Also, the resin is melted using a plurality of extruders and co-extruded from a T-die, or the resin constituting the inner layer and the resin constituting the outer layer are separately formed and then laminated using a press method or a roll nip method. May be.

  The melt-extruded resin is cooled with a cooling roll, air, water, etc., and then reheated by an appropriate method such as hot air, hot water, infrared rays, etc., and 1 by a roll method, a tenter method, a tubular method, etc. It can be stretched biaxially or biaxially.

  Even in the case of applications that require shrinkage characteristics in a substantially uniaxial direction, such as heat shrinkable labels for PET bottles, it is also effective to stretch the film in a range that does not impair the shrinkage characteristics in the vertical direction. The stretching temperature is typically 80 ° C. or higher and 110 ° C. or lower, although it depends on the laminated structure and compounded resin. Furthermore, although the rupture resistance is improved as the draw ratio is increased, the shrinkage ratio is increased accordingly, and it is difficult to obtain a good shrinkage finish. Is highly preferred.

[Heat-shrinkable labels and containers]
The film of the present invention (including a stretched film and a heat-shrinkable film) is excellent in appearance characteristics, impact resistance, transparency, etc., so its use is not particularly limited, but can be printed as necessary. By forming layers, vapor deposition layers and other functional layers, they can be used as various labels used in bottles (blow bottles), trays, lunch boxes, prepared food containers, dairy products containers and the like. In particular, when the film of the present invention is used as a heat-shrinkable label for food containers (for example, PET bottles, glass bottles, preferably PET bottles for soft drinks or foods), a complicated shape (for example, a cylinder with a narrow center, a corner A rectangular column, pentagonal column, hexagonal column, etc.) can be adhered to the shape, and a container with a beautiful label without wrinkles or avatars can be obtained. The molded article and container of the present invention can be produced by using a normal molding method.

  Since the film of the present invention has excellent impact resistance, transparency and excellent appearance, in addition to the heat-shrinkable label material of plastic molded products, the heat-shrinkable film of the present invention has a coefficient of thermal expansion and water absorption. Materials such as metal, porcelain, glass, paper, polyethylene, polypropylene, polybutene and other polyolefin resins, polymethacrylate resins, polycarbonate resins, polyethylene terephthalate, polybutylene terephthalate and other polyester resins, polyamide It can utilize suitably as a heat-shrinkable label raw material of the package (container) which used at least 1 sort (s) chosen from system resin as a structural material.

  As a material constituting the plastic package in which the film of the present invention can be used, in addition to the above resins, polystyrene, rubber-modified impact-resistant polystyrene (HIPS), styrene-butyl acrylate copolymer, styrene-acrylonitrile copolymer, Styrene-maleic anhydride copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), methacrylate ester-butadiene-styrene copolymer (MBS), polyvinyl chloride resin, phenol resin, urea resin, melamine resin, Examples thereof include an epoxy resin, an unsaturated polyester resin, and a silicone resin. These plastic packages may be a mixture of two or more resins or a laminate.

Hereinafter, the present invention will be described in more detail with reference to examples.
In addition, the measured value and evaluation which are shown to an Example were performed as follows. In the examples, the film take-up (flow) direction is described as MD (Machine Direction) or the vertical direction, and the perpendicular direction thereof is described as TD (Transverse Direction) or the horizontal direction.

(1) Average refractive index Average of polylactic acid-based resin, polyolefin-based resin, and polyether / polyolefin-based copolymer used in accordance with JIS K7124 using an Atago Abbe refractometer with sodium D line (589 nm) as a light source The refractive index was measured.

(2) Crystallization temperature (Tc), crystal melting temperature (Tm)
Using Pyris1 DSC manufactured by PerkinElmer Co., Ltd., 10 mg of the polyolefin resin used was heated to 200 ° C. at a heating rate of 10 ° C./min according to JIS K7121, held at 200 ° C. for 5 minutes, and then cooled down. The crystal melting temperature Tm (° C.) and the crystallization temperature Tc (° C.) were determined from the thermogram measured when the temperature was lowered to room temperature at 10 ° C./min.

(3) Amount of heat of crystallization (ΔHc)
Using Pyris1 DSC manufactured by PerkinElmer Co., Ltd., 10 mg of the polyolefin resin used was heated to 200 ° C. at a heating rate of 10 ° C./min according to JIS K7122, and held at 200 ° C. for 5 minutes. The heat of crystallization ΔHc (J / g) was determined from the thermogram measured when the temperature was lowered to room temperature at 10 ° C./min.

(4) Internal haze (cloudiness value)
By measuring the internal haze of the obtained film according to JIS K7105 and dividing by the film thickness, the value converted per 1 μm thickness was described, and the result evaluated according to the following criteria was also shown.
○: Internal haze converted to 1 μm thickness is 0.4% or less ×: Internal haze converted to 1 μm thickness exceeds 0.4%

(5) Tensile elongation The obtained film was cut into MD15 mm × TD100 mm, and a tensile test was conducted according to JIS K7125 at a tensile test speed of 200 mm / min under 23 ° C. conditions. Moreover, it evaluated on the following reference | standard from the measured tensile elongation.
◎: Tensile elongation is 200% or more ○: Tensile elongation is 50% or more and less than 200% △: Tensile elongation is 25% or more and less than 50% ×: Tensile elongation is less than 25%

(6) Hardness The obtained film was cut into MD60 mm × TD4 mm, and using a viscoelasticity measuring device DVA-200 (made by IT Measurement Control Co., Ltd.), vibration frequency 10 Hz, strain 0.1%, temperature increase rate 3 ° C. / Min Under the condition of 25 mm between chucks, the temperature rise was started from −50 ° C. in the MD direction, and the storage elastic modulus (E ′) was measured. The value of the storage elastic modulus (E ′) at 25 ° C. was determined from the obtained data and evaluated as follows.
○: Storage elastic modulus (E ′) is 1.0 × 10 ⁹ Pa or more ×: Storage elastic modulus (E ′) is less than 1.0 × 10 ⁹ Pa

(7) Thermal contraction rate
The obtained film was cut into MD10 mm × TD100 mm, immersed in a hot water bath at 80 ° C. for 10 seconds, and then immersed in cold water at 23 ° C. for 30 seconds to measure the amount of shrinkage in the main shrink direction (lateral direction) of the film. The ratio of the shrinkage to the original size before shrinkage was obtained as a% value.

(8) Appearance The appearance of the obtained film was evaluated according to the following criteria.
○: There are almost no spots on the film and the appearance is good. ×: The spots on the film are intense and the appearance is remarkably bad.

(9) Dispersibility TEM observation of the obtained pellet was performed, and the dispersion state of the polyolefin resin formed as a dispersed phase was evaluated according to the following criteria.
○: The average particle size of the dispersed phase is 1 μm or less ×: The average particle size of the dispersed phase exceeds 1 μm

  The specific contents of the present invention will be described below with reference to examples and comparative examples.

Example 1
As the polylactic acid resin (A), 73% by mass of sufficiently dried amorphous polylactic acid (trade name “Nature Works NW4060”, average refractive index = 1.455) manufactured by Cargill Co., polyolefin resin (B ) As a soft polypropylene (trade name “Versify 2400”, average refractive index = 1.478, ΔHc = 6.8 J / g, Tc = 33.6 ° C., Tm = 16.0 ° C., ethylene content A polyether / polyolefin copolymer (C) with respect to a total amount of 100 parts by mass of 15% by mass, MFR = 2) by 27% by mass, and a total amount of the polylactic acid resin (A) and the polyolefin resin (B). ), 11 parts by mass of a polyether / polyolefin block polymer (trade name “Pelestat 300”, average refractive index = 1.498) manufactured by Sanyo Chemical Industries, Ltd. Kneaded at a set temperature 210 ° C. using, it was extruded from a strand die set temperature 210 ° C., and cooled in a water bath, cut by a strand cutter to obtain pellets. The obtained pellet was subjected to TEM observation and evaluated for dispersibility. The obtained TEM photograph is shown in FIG.
Furthermore, the pelletized resin composition is introduced into a single screw extruder, melt-mixed at each extruder set temperature 210 ° C., extruded from a T-die, taken up with a cast roll at 50 ° C., cooled and solidified, and a film having a thickness of 200 μm. Got.
The results of evaluation using the obtained pellets and film are shown in Table 1. The obtained results were comprehensively evaluated, and a film having no problem with respect to all of the evaluation items was indicated by a symbol (◯), and a film having at least one problem was indicated by a symbol (x).

(Example 2)
In Example 1, the polyether / polyolefin copolymer (C) is changed from “Pelestat 300” to a polyether / polyolefin block polymer (trade name “Pelestat 303”, average refractive index = 1.492) manufactured by Sanyo Kasei Co., Ltd. Except having changed, the pellet and the film were obtained like Example 1. The obtained TEM photograph is shown in FIG. The results of each evaluation are shown in Table 1.

(Example 3)
In Example 1, the polyether / polyolefin copolymer (C) is changed from “Pelestat 300” to a polyether / polyolefin block polymer (trade name “Pelestat 230”, average refractive index = 1.495) manufactured by Sanyo Kasei Co., Ltd. Except having changed, the pellet and the film were obtained like Example 1. The obtained TEM photograph is shown in FIG. The results of each evaluation are shown in Table 1.

(Comparative Example 1)
Pellets and films were obtained in the same manner as in Example 1 except that the polyether / polyolefin copolymer (C) was not blended in Example 1. The obtained TEM photograph is shown in FIG. The results of each evaluation are shown in Table 1.

(Comparative Example 2)
In Example 1, instead of the polyether / polyolefin copolymer (C), an ethylene / (meth) acrylic acid ester copolymer (trade name “Modiper A5200” manufactured by NOF Corporation = ethylene / ethyl acrylate / methacrylic) A pellet and a film were obtained in the same manner as in Example 1 except that (methyl acid copolymer resin) was used. The obtained TEM photograph is shown in FIG. The results of each evaluation are shown in Table 1.

  As shown in Table 1 and FIGS. 1 to 3, a mixed resin composition of a polylactic acid resin (A), a polyolefin resin (B) and a polyether / polyolefin copolymer (C) defined in the present invention is used. The film used has good dispersibility of the disperse phase (polyolefin component) in the continuous phase (polylactic acid component), and has excellent balance in all the characteristics of internal haze (transparency), tensile elongation, and hardness. (Examples 1 to 3).

  On the other hand, as shown in Table 1, FIG. 4 and FIG. 5, when the polyether / polyolefin copolymer (C) is not added or when other compatibilizer is used, the tensile elongation is However, it did not reach sufficient reforming (Comparative Examples 1 and 2). This is considered to be a result resulting from the dispersibility of the dispersed phase.

Example 4
As the polylactic acid-based resin (A), 73% by mass of sufficiently dried amorphous polylactic acid (trade name “Nature Works NW4060”) manufactured by Cargill Co., and manufactured by Dow Chemical Company as the polyolefin-based resin (B) Soft polypropylene (trade name “Versify 2200”, average refractive index = 1.486, ΔHc = 29.5 J / g, Tc = 66.3 ° C., Tm = 136.1 ° C., ethylene content = 9% by mass, MFR = 2) 27% by mass and a total amount of 100 parts by mass of the polylactic acid resin (A) and the polyolefin resin (B), as a polyether / polyolefin copolymer (C), manufactured by Sanyo Chemical Co., Ltd. 11 parts by mass of a polyether / polyolefin block polymer (trade name “Pelestat 300”) is blended and melt-kneaded at a set temperature of 210 ° C. using a twin screw extruder. 0 ℃ of T-die from extrusion, drawing by a cast roll of 50 ° C., to obtain a film having a thickness of 200μm solidified by cooling. The results of evaluation using the obtained film are shown in Table 2.

(Example 5)
In Example 4, the polyolefin resin (B) was changed from “Versify 2200” to soft polypropylene (trade name “Versify 2400”) manufactured by Dow Chemical Co., Ltd., and the polylactic acid resin (A) and the polyolefin resin (B ) And 5 parts by mass of a polyether / polyolefin block polymer (trade name “Pelestat 300”) manufactured by Sanyo Kasei Co., Ltd. as a polyether / polyolefin copolymer (C). A film was obtained in the same manner as in Example 4. The results of each evaluation are shown in Table 2.

(Comparative Example 3)
In Example 4, the content of the polylactic acid resin (A) was changed to 94% by mass, and the polyolefin resin (B) was changed to soft polypropylene (trade name “Versify 2400”) manufactured by Dow Chemical Company. A film was obtained in the same manner as in Example 4 except that the content of B) was changed to 6% by mass. The results of each evaluation are shown in Table 2.

(Comparative Example 4)
In Example 4, the polyolefin resin (B) was changed from “Versify 2200” to soft polypropylene (trade name “Versify 2400”) manufactured by Dow Chemical Company, and the polylactic acid resin (A) and the polyolefin resin (B) ) Except for 30 parts by mass of polyether / polyolefin block polymer (trade name “Pelestat 300”) manufactured by Sanyo Kasei Co., Ltd. as a polyether / polyolefin copolymer (C). A film was obtained in the same manner as in Example 4. The results of each evaluation are shown in Table 2.

(Reference Example 1)
In Example 4, the polyolefin resin (B) was changed from “Versify 2200” to polypropylene manufactured by Sumitomo Chemical Co., Ltd., trade name “Nobrene FH3315” (average refractive index = 1.503, ΔHc = 85.0 J / g, Tc = 103). A film was obtained in the same manner as in Example 4 except that the temperature was changed to 0.6 ° C., Tm = 144.6 ° C., ethylene content = 3.2% by mass, MFR = 3). The results of each evaluation are shown in Table 2.

(Example 6)
The film obtained in Example 1 was introduced into a biaxial stretching apparatus in which the temperature in the tank was 80 ° C., and the film was sandwiched by an air chuck and then stretched 4 times in the transverse direction at a stretching speed of 10 mm / min. . Then, after cooling and solidifying, the film was taken out to obtain a stretched film having a thickness of 50 μm. The results of each evaluation are shown in Table 3.

From Table 2, when the mixing amount of the polylactic acid-based resin (A), the polyolefin-based resin (B), and the polyether / polyolefin-based copolymer (C) is within the range specified in the present invention, the internal haze ( It can be confirmed that the balance of transparency, tensile elongation, hardness, and appearance is excellent (Examples 4 and 5).
Moreover, from Table 3, a stretched film comprising the resin composition of the present invention as a main component is considered to be suitable for use as a heat-shrinkable film because a stretched film having a good balance between heat shrinkage properties and various physical properties is obtained ( Example 6).
On the other hand, when the content of the polyolefin resin (B) or the polyether / polyolefin copolymer (C) deviates from the range defined in the present invention from Table 2, the balance of physical properties is lost and sufficient modification is achieved. It was confirmed that it did not reach (Comparative Examples 3 and 4). Furthermore, when the crystallization heat quantity ΔHc of the polyolefin resin (B) exceeds 40 J / g, it can be seen that the internal haze value tends to increase.

  By using the resin composition of the present invention, it is possible to produce a molded article, a stretched film, and a heat-shrinkable film excellent in appearance, transparency, and impact resistance. Various applications can be expected as a base material for packaging materials, containers, medical materials, building materials, members for electric and electronic equipment, information recording films, sheet materials, labels, and adhesive tapes.

1 Film 2 Dispersed Phase 3 Continuous Phase

Claims (10)

A resin composition comprising a polylactic acid resin (A), a polyolefin resin (B), and a polyether / polyolefin copolymer (C), wherein the polylactic acid resin (A) and a polyolefin resin ( When the total of B) is 100% by mass, the polylactic acid resin (A) is 30% by mass to 90% by mass, the polyolefin resin (B) is 10% by mass to 70% by mass, and 1 part by mass or more and 25 parts by mass or less of a polyether / polyolefin copolymer (C) with respect to a total of 100 parts by mass of the polylactic acid resin (A) and the polyolefin resin (B) Resin composition. A resin composition comprising a polylactic acid-based resin (A), a polyolefin-based resin (B), and a polyether / polyolefin-based copolymer (C), and the total of all the components of this resin composition is 100 mass %, The polylactic acid component is 24% by mass to 90% by mass, the polyolefin component is 8% by mass to 72% by mass, and the polyether component is 0.2% by mass to 10% by mass. A resin composition. Using a differential scanning calorimeter, a polyolefin resin (B) measured when heated to 200 ° C. at a heating rate of 10 ° C./min, held at 200 ° C. for 5 minutes and then cooled to room temperature at a cooling rate of 10 ° C./min. 3) The resin composition according to claim 1 or 2, wherein the crystallization heat quantity ΔHc is 40 J / g or less. A molded product comprising the resin composition according to claim 1 or 2 as a main component. A film comprising the resin composition according to claim 1 or 2 as a main component and having an internal haze converted to a thickness of 1 μm of 0.40% or less. Included in the film, measured using a differential scanning calorimeter, heated to 200 ° C. at a heating rate of 10 ° C./min, held at 200 ° C. for 5 minutes, and then cooled to room temperature at a cooling rate of 10 ° C./min. The film according to claim 5, wherein the polyolefin resin (B) has a crystallization heat amount ΔHc of 40 J / g or less. A stretched film obtained by stretching the film according to claim 5 or 6 in at least one direction. The film according to claim 5 or 6 is stretched in at least one direction and has a heat shrinkage ratio of 20% or more in the main shrinkage direction when immersed in warm water at 80 ° C for 10 seconds. Shrink film. A heat-shrinkable label using the heat-shrinkable film according to claim 8 as a substrate. A container equipped with the heat-shrinkable label according to claim 9.

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