WO2022059651A1 - Heat-shrinkable film - Google Patents

Heat-shrinkable film Download PDF

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Publication number
WO2022059651A1
WO2022059651A1 PCT/JP2021/033601 JP2021033601W WO2022059651A1 WO 2022059651 A1 WO2022059651 A1 WO 2022059651A1 JP 2021033601 W JP2021033601 W JP 2021033601W WO 2022059651 A1 WO2022059651 A1 WO 2022059651A1
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WIPO (PCT)
Prior art keywords
resin
based resin
aliphatic
resin composition
aromatic polyester
Prior art date
Application number
PCT/JP2021/033601
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French (fr)
Japanese (ja)
Inventor
朋弥 中村
誠 大西
博行 松田
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大倉工業株式会社
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Priority to JP2022550554A priority Critical patent/JPWO2022059651A1/ja
Publication of WO2022059651A1 publication Critical patent/WO2022059651A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C61/00—Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor
    • B29C61/06—Making preforms having internal stresses, e.g. plastic memory
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/027—Thermal properties
    • B32B7/028—Heat-shrinkability
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C08L101/16—Compositions of unspecified macromolecular compounds the macromolecular compounds being biodegradable
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
    • C08L67/03—Polyesters derived from dicarboxylic acids and dihydroxy compounds the dicarboxylic acids and dihydroxy compounds having the carboxyl- and the hydroxy groups directly linked to aromatic rings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones

Definitions

  • the present invention relates to a heat-shrinkable film used for shrink wrapping and the like, which has biodegradability.
  • heat-shrinkable films have been widely used in the packaging field.
  • the synthetic resin used for the heat-shrinkable film include polypropylene-based resin, polyethylene-based resin, polyvinyl chloride-based resin, and polystyrene-based resin.
  • the heat-shrinkable film made of these synthetic resins is dumped into the natural environment after finishing its role as a packaging material, it is difficult to decompose due to its chemical stability and remains in the natural environment for a long period of time. Therefore, it contributes to environmental pollution. Therefore, a heat-shrinkable film made of a biodegradable resin that is decomposed by the action of microorganisms is attracting attention.
  • Patent Document 1 is a laminated film having both outer layers made of a polylactic acid-based resin and an intermediate layer made of an aliphatic-aromatic polyester resin, and the ratio of the polylactic acid-based resin in all layers is 15 to 55 weight. %, The invention relates to a biodegradable biaxially stretched film in which the ratio of the aliphatic-aromatic polyester resin is 45 to 85% by weight.
  • the biodegradable biaxially stretched film is not only excellent in stretchability but also excellent in low temperature shrinkage and flexibility, so that it can be used for shrink wrapping.
  • the film thus obtained has a weak interlayer adhesive strength between both outer layers made of a polylactic acid resin and an intermediate layer made of an aliphatic-aromatic polyester resin, and when the film is bent, peeling occurs between the layers, which is beautiful. There was a problem that the sex was impaired.
  • the present invention is a heat-shrinkable film made of a biodegradable resin and excellent in stretchability, low-temperature shrinkage, flexibility, etc., which is used for shrink wrapping, and obtains a heat-shrinkable film having good interlayer adhesion. Make it an issue. At the same time, it is an object to provide a heat-shrinkable film having good fusing seal strength, elongation, and transparency.
  • the present inventors have diligently studied the resin composition forming each layer in order to enhance the adhesion between the layers, and have reached the present invention. That is, according to the present invention, the heat-shrinkable films of the following [1] to [3] are proposed as means for solving the above problems.
  • the resin composition B comprises a polylactic resin and an aliphatic-aromatic polyester resin, and the polylactic resin: aliphatic-aromatic polyester.
  • a heat-shrinkable film comprising a resin in a ratio of 2.0 to 20.0% by weight: 98.0 to 80.0.
  • the resin composition B contains a polylactic acid-based resin and an aliphatic-aromatic polyester-based resin in a proportion of 17.5 to 2.5% by weight, and the polylactic acid-based resin: aliphatic-aromatic polyester-based resin.
  • a three-layer film including an outer layer / intermediate layer / outer layer in this order, characterized in that the thickness ratio of each layer is outer layer: intermediate layer: outer layer 1: 4: 1 to 1: 8: 1.
  • the heat-shrinkable film of the present invention is made of a biodegradable resin that decomposes by the action of microorganisms, the influence on the environment can be reduced. Not only is it excellent in stretchability, but it is also excellent in low temperature shrinkage, flexibility, transparency, etc., and can be suitably used for shrink wrapping. Furthermore, since the resin composition forming each layer has been reviewed, the interlayer adhesive strength is increased, and the risk of delamination due to impact such as bending is reduced.
  • the heat-shrinkable film of the present invention includes at least both outer layers and an intermediate layer.
  • Both outer layers are a resin containing a polylactic acid resin (hereinafter abbreviated as PLA as necessary) as a main component and an aliphatic-aromatic polyester resin (hereinafter abbreviated as PBAT as necessary) as a sub-component.
  • Consists of composition A. Polylactic acid resin (PLA)
  • PLA is a homopolymer or copolymer of L-lactic acid or D-lactic acid, or a mixture of homopolymers.
  • poly L-lactic acid whose structural unit is L-lactic acid
  • poly D-lactic acid whose structural unit is D-lactic acid poly LD-lactic acid which is a copolymer of L-lactic acid and D-lactic acid, etc.
  • One type or a plurality of types can be blended and used.
  • the proportion of D-lactic acid in PLA is preferably 0.5 to 10.0% by weight.
  • polylactic acid LuminyLX175 manufactured by Total-Corbion can be used.
  • the PLA may be copolymerized with another hydroxycarboxylic acid as long as the properties of the resin are not impaired, or may contain a small amount of chain extender residue.
  • Other hydroxycarboxylic acid units include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, etc. Examples thereof include bifunctional aliphatic hydroxycarboxylic acids such as 2-methyllactic acid and 2-hydroxycaproic acid, and lactones such as caprolactone, butyrolactone and valerolactone.
  • Such other hydroxycarboxylic acid units are preferably used in less than 15 mol% in PLA.
  • PBAT is a polyester obtained by condensation polymerization of an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid and a diol.
  • the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedic acid and the like. Of these, succinic acid or adipic acid is preferable in consideration of biodegradability.
  • the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like.
  • terephthalic acid and isophthalic acid are preferable, and terephthalic acid is particularly preferable from the viewpoint of polymerizable property.
  • an aromatic dicarboxylic acid in which a part of the aromatic ring is replaced with a sulfonate can be mentioned.
  • Aliphatic diols are preferably used as the diol component, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol.
  • diols having 2 or more carbon atoms and 4 or less carbon atoms are preferable, ethylene glycol and 1,4-butanediol are more preferable, and 1,4-butanediol is particularly preferable.
  • two or more kinds of the aliphatic dicarboxylic acid component, the aliphatic diol component and the aromatic dicarboxylic acid component can be used.
  • PBAT "Ecoflex" (registered trademark) manufactured by BASF, which contains a condensation polymer of adipic acid, terephthalic acid and 1,4-butanediol as a main component, can be used.
  • the blending ratio of PLA in both outer layers is less than 70% by weight, the transparency of the film deteriorates.
  • the compounding ratio of PBAT in both outer layers is less than 2.0% by weight, delamination may occur between both outer layers and the intermediate layer when the film is bent.
  • BASF's "Ecobio" registered trademark
  • BASF's "Ecobio" contains PLA and PBAT
  • the resin is used, and PLA and PBAT are further added so that the blending ratio of PLA and PBAT is within the above range. It can also be used.
  • the intermediate layer is composed of a resin composition B containing PBAT as a main component and PLA as a sub component.
  • PBAT and PLA used for the intermediate layer the above-mentioned resin can be used without particular limitation.
  • the compounding ratio of PLA in the middle is less than 2.0% by weight, When the film is bent, delamination may occur between both outer layers and the intermediate layer.
  • the blending ratio of PBAT in the intermediate layer is less than 80.0% by weight, the flexibility of the obtained film may decrease. Since BASF's "Ecobio" (registered trademark) contains PLA and PBAT, the resin is used, and PLA and PBAT are further added so that the blending ratio of PLA and PBAT is within the above range. It can also be used.
  • Ecobio registered trademark
  • the resin composition (A) and the resin composition (B) include, for example, lubricants, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, pigments, dyes, surfactants, antiblocking agents, and modifications.
  • a resin or the like can be used as long as the effect of the present invention is not impaired.
  • the compatibilizer are the above-mentioned epoxy group-containing copolymers based on carboxylic acid anhydrides such as maleic anhydride and in particular styrene, acrylic acid esters and / or methacrylic acid esters.
  • the unit having the epoxy group is preferably glycidyl (meth) acrylate.
  • Epoxy group-containing copolymers of the above type are sold, for example, by BASF Resins B.V. under the brand Joncryl® ADR.
  • Particularly suitable as a compatibilizer is, for example, Joncryl® ADR 4368.
  • the amount of the compatibilizer added is not particularly limited, but for example, 0.01 to 2.00 parts by weight may be added to a total of 100 parts by weight of PLA and PBAT.
  • the heat-shrinkable film of the present invention has both outer layers made of the resin composition A and an intermediate layer made of the resin composition B between them.
  • the outer layer (resin composition A) / intermediate layer (resin composition). has a three-layer structure composed of a substance B) / an outer layer (resin composition A). Further, it has a five-layer structure of an outer layer (resin composition A) / intermediate layer (resin composition B) / intermediate layer (resin composition A) / intermediate layer (resin composition B) / outer layer (resin composition A). You may.
  • An intermediate layer made of the resin composition C contained in a superb ratio may be further contained.
  • the total thickness of the heat-shrinkable film of the present invention is preferably 10 to 30 ⁇ m, preferably 10 to 25 ⁇ m. If the total thickness of the film is less than 10 ⁇ m, the strength is insufficient. Further, if it exceeds 25 ⁇ m, the flexibility is lowered and the amount of the resin used is further increased, so that the economic efficiency is also lowered.
  • the ratio of the intermediate layer is less than 4, the flexibility of the heat-shrinkable film is lowered, and when the ratio of the intermediate layer is more than 8, the shrinkage characteristics are deteriorated. Further, when the thickness of the surface layer is less than 1 ⁇ m, the transparency of the heat-shrinkable film is lowered.
  • the heat-shrinkable film of the present invention has a shrinkage rate in the longitudinal and horizontal directions in glycerin of 30% or more at 90 ° C. and 50% or more at 110 ° C. If the shrinkage rate in 90 ° C. glycerin is 30% or more, that is, if the film shrinkage is excellent at low temperature, the film shrinkage temperature at the time of shrinkage packaging can be set low and the heating time can be set short, so that the film is easily deteriorated by heat. It is suitably used for packaging packages.
  • glycerin shows a value close to the final shrinkage rate of the film, and if this value is less than 50%, the corners of the film do not shrink sufficiently when shrink-wrapped and have a hard protrusion. There is a risk that a beautiful package cannot be obtained due to the formation of so-called corners or wrinkles due to insufficient shrinkage of the portion in contact with the packaged object.
  • the above-mentioned resin composition is formed into a film by using, for example, an inflation film forming method or a T-die film forming method, and this is formed by a roll stretching method and / or a tenter stretching method. It can be produced by uniaxial stretching or biaxial stretching. Further, when the film is formed by the inflation film forming method, it can be produced by increasing the blow-up ratio and the draw ratio and performing the stretching treatment. Further, a tubular film formed by an inflation film forming method can be stretched and produced by a tubular stretching method. In addition, as the method for producing the heat-shrinkable film of the present invention, a conventionally known method can be adopted.
  • ⁇ Bending peeling test> The obtained film is cut in a bent state, and the peeled state of the outer layer in the cross section of the film is observed with a microscope. Those with peeling of the outer layer are evaluated as x, and those without peeling are evaluated as ⁇ .
  • ⁇ Haze> The haze of the obtained film is measured according to JIS K 7136: 2000. NDH-4000 manufactured by Nippon Denshoku Co., Ltd. is used for the measurement. It can be judged that the haze is very good when it is 5% or less.
  • ⁇ Fusing seal strength> The obtained film is fused and sealed at a sealing temperature of 190 ° C. and a sealing time of 0.5 seconds, and then cut to a width of 15 mm. The fusing seal strength of the obtained test piece is measured at a tensile speed of 500 mm / min according to the JIS Z 1711 8.4 heat seal strength test. AG-1 KNISMO manufactured by Shimadzu Corporation is used for the measurement.
  • the fusing seal strength is very good when it exceeds 11 N / 15 mm.
  • ⁇ Fusing seal elongation> When measuring the fusing seal strength, it is obtained from the distance between chucks when the seal portion breaks. Specifically, when the initial distance between chucks is a and the distance between chucks when the seal portion is broken is b, it is calculated as 100 ⁇ (ba) / a. It can be judged that the elongation of the fusing seal is very good when it exceeds 20%.
  • Example 1 The resin composition A for the outer layer and the resin composition B for the intermediate layer shown in Table 1 are supplied to separate extruders, and the outer layer (resin composition A) / intermediate layer (resin composition) is subjected to the T-die coextrusion method.
  • Example 1 The performance of the obtained film is also shown in Table 1.
  • Example 2 to 6 Comparative Examples 1 to 4
  • Each film was obtained in the same manner as in Example 1 except that the resin composition was changed as described in Table 1 or 2.
  • the evaluations of the obtained films are also shown in Tables 1 and 2.
  • the heat-shrinkable films of Examples 1 to 6 all had high interlayer adhesion strength, and even when the films were bent, delamination did not occur.
  • the PLA: PBAT in both outer layers is in the range of 82.5 to 97.5% by weight: 17.5 to 2.5% by weight
  • the PLA: PBAT in the intermediate layer is 4.0 to 15.0.
  • the films of Examples 1 to 3 in the range of% by weight: 96.0 to 85.0% by weight also had high fusing seal strength.
  • the films of Examples 1 to 4 in which the PLA: PBAT in the entire heat-shrinkable film was in the range of 25.0 to 35.0% by weight: 75.0 to 65.0% by weight had good fusing seal elongation. rice field. If the fusing seal has good elongation, the seal portion is unlikely to break even if an impact is applied to the seal portion.
  • the films of Comparative Examples 1 to 4 had low interlayer adhesion strength, and delamination of the films was observed when the films were bent. Further, the film of Comparative Example 2 has a problem that the amount of PBAT in the entire film exceeds 80% by weight and the fusing seal strength is low. Further, in the films of Examples 5 and 6 and Comparative Example 4, the amount of PLA in the entire heat-shrinkable film was 40% by weight or less, but it exceeded the preferable range (35% by weight or less), and the fusing seal elongation was extended. It was low.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Laminated Bodies (AREA)

Abstract

[Problem] To obtain a heat-shrinkable film which comprises biodegradable resins, is excellent in terms of stretchability, low-temperature shrinkability, flexibility, etc., and is for use in shrink packaging and which has satisfactory interlaminar adhesion.　[Solution] A heat-shrinkable film comprising both outer layers constituted of resin composition A, which comprises a poly(lactic acid)-based resin as a main component, and an interlayer constituted of resin composition B, which comprises an aliphatic/aromatic polyester-based resin as a main component, characterized in that the resin composition A comprises the poly(lactic acid)-based resin and an aliphatic/aromatic polyester-based resin in such a proportion that [poly(lactic acid)-based resin]/[aliphatic/aromatic polyester-based resin]=(70.0-98.0 wt%)/(30.0-2.0 wt%) and the resin composition B comprises a poly(lactic acid)-based resin and the aliphatic/aromatic polyester-based resin in such a proportion that [poly(lactic acid)-based resin]/[aliphatic/aromatic polyester-based resin]=(2.0-20.0 wt%)/(98.0-80.0 wt%).

Description

熱収縮性フィルムHeat shrinkable film
　本発明は、シュリンク包装等に用いられる熱収縮性フィルムであって、生分解性を有する熱収縮性フィルムに関する。 The present invention relates to a heat-shrinkable film used for shrink wrapping and the like, which has biodegradability.
　従来、包装分野において熱収縮性フィルムが多用されている。当該熱収縮性フィルムに用いられる合成樹脂として、ポリプロピレン系樹脂やポリエチレン系樹脂、ポリ塩化ビニル系樹脂、ポリスチレン系樹脂などが挙げられる。しかしながら、これらの合成樹脂からなる熱収縮性フィルムは、包装材としての役目を終えた後に自然環境中に投棄されると、その化学的安定性のため分解し難く、自然環境に長期にわたって残留する為、環境汚染の一因となっている。そのため、微生物の働きによって分解される生分解性樹脂からなる熱収縮性フィルムが注目されている。 Conventionally, heat-shrinkable films have been widely used in the packaging field. Examples of the synthetic resin used for the heat-shrinkable film include polypropylene-based resin, polyethylene-based resin, polyvinyl chloride-based resin, and polystyrene-based resin. However, when the heat-shrinkable film made of these synthetic resins is dumped into the natural environment after finishing its role as a packaging material, it is difficult to decompose due to its chemical stability and remains in the natural environment for a long period of time. Therefore, it contributes to environmental pollution. Therefore, a heat-shrinkable film made of a biodegradable resin that is decomposed by the action of microorganisms is attracting attention.
　特許文献１は、ポリ乳酸系樹脂からなる両外層と、脂肪族－芳香族ポリエステル系樹脂からなる中間層とを有する積層フィルムであって、全層におけるポリ乳酸系樹脂の割合が１５～５５重量％、脂肪族―芳香族ポリエステル系樹脂の割合が４５～８５重量％である生分解性二軸延伸フィルムに関する発明である。当該生分解性二軸延伸フィルムは延伸性に優れているのみならず、低温収縮性や柔軟性に優れているので、シュリンク包装に用いることができる。しかしながらこうして得られたフィルムは、ポリ乳酸系樹脂からなる両外層と脂肪族－芳香族ポリエステル系樹脂からなる中間層との層間接着強度が弱く、フィルムを折り曲げた際、層間で剥がれが生じ、美麗性が損なわれてしまうという問題点があった。 Patent Document 1 is a laminated film having both outer layers made of a polylactic acid-based resin and an intermediate layer made of an aliphatic-aromatic polyester resin, and the ratio of the polylactic acid-based resin in all layers is 15 to 55 weight. %, The invention relates to a biodegradable biaxially stretched film in which the ratio of the aliphatic-aromatic polyester resin is 45 to 85% by weight. The biodegradable biaxially stretched film is not only excellent in stretchability but also excellent in low temperature shrinkage and flexibility, so that it can be used for shrink wrapping. However, the film thus obtained has a weak interlayer adhesive strength between both outer layers made of a polylactic acid resin and an intermediate layer made of an aliphatic-aromatic polyester resin, and when the film is bent, peeling occurs between the layers, which is beautiful. There was a problem that the sex was impaired.
特開２００６－１５７２０号公報Japanese Unexamined Patent Publication No. 2006-15720
　本発明は生分解性樹脂からなり、延伸性、低温収縮性、柔軟性等に優れたシュリンク包装に用いられる熱収縮性フィルムであって、層間接着性の良好な熱収縮性フィルムを得ることを課題とする。併せて溶断シール強度・伸び、透明性が良好な熱収縮性フィルムの提供を課題とする。 The present invention is a heat-shrinkable film made of a biodegradable resin and excellent in stretchability, low-temperature shrinkage, flexibility, etc., which is used for shrink wrapping, and obtains a heat-shrinkable film having good interlayer adhesion. Make it an issue. At the same time, it is an object to provide a heat-shrinkable film having good fusing seal strength, elongation, and transparency.
　本発明者らは層間の密着性を高めるために、各層を形成する樹脂組成物を鋭意検討し、本発明に至った。すなわち本発明によると上記課題を解決する為の手段として以下［１］～［３］の熱収縮性フィルムが提案される。
［１］ポリ乳酸系樹脂を主成分とする樹脂組成物Ａからなる両外層と、脂肪族－芳香族ポリエステル系樹脂を主成分とする樹脂組成物Ｂからなる中間層と、を有する熱収縮性フィルムであって、前記樹脂組成物Ａが、ポリ乳酸系樹脂と脂肪族－芳香族ポリエステル系樹脂とを、ポリ乳酸系樹脂：脂肪族－芳香族ポリエステル系樹脂＝７０．０～９８．０重量％：３０．０～２．０重量％の割合で含み、前記樹脂組成物Ｂが、ポリ乳酸系樹脂と脂肪族－芳香族ポリエステル系樹脂とを、ポリ乳酸系樹脂：脂肪族－芳香族ポリエステル系樹脂＝２．０～２０．０重量％：９８．０～８０．０の割合で含むことを特徴とする熱収縮性フィルム。
［２］　前記樹脂組成物Ａが、ポリ乳酸系樹脂と脂肪族－芳香族ポリエステル系樹脂とを、ポリ乳酸系樹脂：脂肪族－芳香族ポリエステル系樹脂＝８２．５～９７．５重量％：１７．５～２．５重量％の割合で含み、前記樹脂組成物Ｂが、ポリ乳酸系樹脂と脂肪族－芳香族ポリエステル系樹脂とを、ポリ乳酸系樹脂：脂肪族－芳香族ポリエステル系樹脂＝４．０～１５．０重量％：９６．０～８５．０の割合で含むことを特徴とする［１］記載の熱収縮性フィルム。
［３］外層／中間層／外層を順に備える３層フィルムであって、各層の厚さ割合が、外層：中間層：外層＝１：４：１～１：８：１であることを特徴とする［１］または［２］記載の熱収縮性フィルム。 The present inventors have diligently studied the resin composition forming each layer in order to enhance the adhesion between the layers, and have reached the present invention. That is, according to the present invention, the heat-shrinkable films of the following [1] to [3] are proposed as means for solving the above problems.
[1] Heat shrinkability having both outer layers made of a resin composition A containing a polylactic resin as a main component and an intermediate layer made of a resin composition B containing an aliphatic-aromatic polyester resin as a main component. In the film, the resin composition A comprises a polylactic acid-based resin and an aliphatic-aromatic polyester-based resin, and a polylactic acid-based resin: aliphatic-aromatic polyester-based resin = 70.0 to 98.0 weight. %: 30.0 to 2.0% by weight, and the resin composition B comprises a polylactic resin and an aliphatic-aromatic polyester resin, and the polylactic resin: aliphatic-aromatic polyester. A heat-shrinkable film comprising a resin in a ratio of 2.0 to 20.0% by weight: 98.0 to 80.0.
[2] The resin composition A comprises a polylactic resin and an aliphatic-aromatic polyester resin, and the polylactic resin: aliphatic-aromatic polyester resin = 82.5 to 97.5% by weight: The resin composition B contains a polylactic acid-based resin and an aliphatic-aromatic polyester-based resin in a proportion of 17.5 to 2.5% by weight, and the polylactic acid-based resin: aliphatic-aromatic polyester-based resin. The heat-shrinkable film according to [1], which comprises a ratio of 4.0 to 15.0% by weight: 96.0 to 85.0.
[3] A three-layer film including an outer layer / intermediate layer / outer layer in this order, characterized in that the thickness ratio of each layer is outer layer: intermediate layer: outer layer = 1: 4: 1 to 1: 8: 1. The heat-shrinkable film according to [1] or [2].
　本発明の熱収縮性フィルムは、微生物の働きにより分解する生分解性樹脂から成るため、環境に与える影響を低減することができる。また延伸性に優れているのみならず、低温収縮性や柔軟性、透明性等にも優れ、シュリンク包装に好適に用いることができる。
　更に各層を形成する樹脂組成物を見直したため、層間接着力が高まり、折り曲げなどの衝撃により層間剥離するリスクが低減される。 Since the heat-shrinkable film of the present invention is made of a biodegradable resin that decomposes by the action of microorganisms, the influence on the environment can be reduced. Not only is it excellent in stretchability, but it is also excellent in low temperature shrinkage, flexibility, transparency, etc., and can be suitably used for shrink wrapping.
Furthermore, since the resin composition forming each layer has been reviewed, the interlayer adhesive strength is increased, and the risk of delamination due to impact such as bending is reduced.
　以下、本発明について詳細に説明するが、本発明は以下の形態に限定されるものではなく、同様の効果を奏する範囲において種々の実施形態をとることができる。
　本発明の熱収縮性フィルムは、少なくとも両外層と中間層とを備える。 Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments, and various embodiments can be taken as long as the same effects can be obtained.
The heat-shrinkable film of the present invention includes at least both outer layers and an intermediate layer.
［両外層］
　両外層は、ポリ乳酸系樹脂（以下、必要に応じＰＬＡと略称する）を主成分とし、更に脂肪族－芳香族ポリエステル系樹脂（以下、必要に応じＰＢＡＴと略称する）を副成分として含む樹脂組成物Ａからなる。
（ポリ乳酸系樹脂（ＰＬＡ））
　ＰＬＡとは、Ｌ－乳酸またはＤ－乳酸の単独重合体や共重合体、または単独重合体の混合物である。本発明では、構造単位がＬ－乳酸であるポリＬ－乳酸や、構造単位がＤ－乳酸であるポリＤ－乳酸、Ｌ－乳酸とＤ－乳酸の共重合体であるポリＬＤ－乳酸などの一種或いは複数種をブレンドして用いることができる。ＰＬＡにおけるＤ－乳酸の割合は０．５～１０．０重量％であることが好ましい。このようなＰＬＡとして、Ｔｏｔａｌ－Ｃｏｒｂｉｏｎ社製のポリ乳酸　ＬｕｍｉｎｙＬＸ１７５などを利用することができる。 [Both outer layers]
Both outer layers are a resin containing a polylactic acid resin (hereinafter abbreviated as PLA as necessary) as a main component and an aliphatic-aromatic polyester resin (hereinafter abbreviated as PBAT as necessary) as a sub-component. Consists of composition A.
(Polylactic acid resin (PLA))
PLA is a homopolymer or copolymer of L-lactic acid or D-lactic acid, or a mixture of homopolymers. In the present invention, poly L-lactic acid whose structural unit is L-lactic acid, poly D-lactic acid whose structural unit is D-lactic acid, poly LD-lactic acid which is a copolymer of L-lactic acid and D-lactic acid, etc. One type or a plurality of types can be blended and used. The proportion of D-lactic acid in PLA is preferably 0.5 to 10.0% by weight. As such a PLA, polylactic acid LuminyLX175 manufactured by Total-Corbion can be used.
　尚、ＰＬＡは、樹脂の性質を損なわない範囲で、他のヒドロキシカルボン酸を共重合してもよく、また少量の鎖延長剤残基を含んでいてもよい。他のヒドロキシカルボン酸単位としては、グリコール酸、３－ヒドロキシ酪酸、４－ヒドロキシ酪酸、２－ヒドロキシ－ｎ－酪酸、２－ヒドロキシ－３，３－ジメチル酪酸、２－ヒドロキシ－３－メチル酪酸、２－メチル乳酸、２－ヒドロキシカプロン酸等の２官能脂肪族ヒドロキシカルボン酸類、およびカプロラクトン、ブチロラクトン、バレロラクトン等のラクトン類が挙げられる。このような他のヒドロキシカルボン酸単位は、ＰＬＡ中１５モル％未満で使用するのがよい。 The PLA may be copolymerized with another hydroxycarboxylic acid as long as the properties of the resin are not impaired, or may contain a small amount of chain extender residue. Other hydroxycarboxylic acid units include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, etc. Examples thereof include bifunctional aliphatic hydroxycarboxylic acids such as 2-methyllactic acid and 2-hydroxycaproic acid, and lactones such as caprolactone, butyrolactone and valerolactone. Such other hydroxycarboxylic acid units are preferably used in less than 15 mol% in PLA.
（脂肪族－芳香族ポリエステル系樹脂（ＰＢＡＴ））
　ＰＢＡＴは、脂肪族ジカルボン酸と芳香族ジカルボン酸とジオールとを縮合重合して得られるポリエステルである。
　脂肪族ジカルボン酸としては、コハク酸、アジピン酸、スベリン酸、セバシン酸、ドデカン二酸等が挙げられる。中でも、生分解性を考慮すると、コハク酸またはアジピン酸が好ましい。また芳香族ジカルボン酸としては、テレフタル酸、イソフタル酸、ナフタレンジカルボン酸等が挙げられ、中でも、重合性の面から、テレフタル酸、イソフタル酸が好ましく、テレフタル酸が特に好ましい。また、芳香環の一部がスルホン酸塩で置換されている芳香族ジカルボン酸が挙げられる。ジオール成分としては脂肪族ジオールが好適に用いられ、特にエチレングリコール、１，３－プロパンジオール、１，４－ブタンジオール、１，４－シクロヘキサンジメタノール等が挙げられる。中でも、生分解性を考慮すると、炭素数２以上４以下のジオールが好ましく、エチレングリコール、１，４－ブタンジオールがより好ましく、１，４－ブタンジオールが特に好ましい。なお、脂肪族ジカルボン酸成分、脂肪族ジオール成分および芳香族ジカルボン酸成分は、それぞれ２種類以上を用いることもできる。
　ＰＢＡＴとして、アジピン酸とテレフタル酸と１，４－ブタンジオールの縮合重合物を主成分とするＢＡＳＦ社製「エコフレックス」（登録商標）などを利用することができる。 (Aliphatic-Aromatic Polyester Resin (PBAT))
PBAT is a polyester obtained by condensation polymerization of an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid and a diol.
Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedic acid and the like. Of these, succinic acid or adipic acid is preferable in consideration of biodegradability. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like. Among them, terephthalic acid and isophthalic acid are preferable, and terephthalic acid is particularly preferable from the viewpoint of polymerizable property. In addition, an aromatic dicarboxylic acid in which a part of the aromatic ring is replaced with a sulfonate can be mentioned. Aliphatic diols are preferably used as the diol component, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Among them, in consideration of biodegradability, diols having 2 or more carbon atoms and 4 or less carbon atoms are preferable, ethylene glycol and 1,4-butanediol are more preferable, and 1,4-butanediol is particularly preferable. It should be noted that two or more kinds of the aliphatic dicarboxylic acid component, the aliphatic diol component and the aromatic dicarboxylic acid component can be used.
As PBAT, "Ecoflex" (registered trademark) manufactured by BASF, which contains a condensation polymer of adipic acid, terephthalic acid and 1,4-butanediol as a main component, can be used.
　樹脂組成物（Ａ）におけるＰＬＡとＰＢＡＴの配合割合は、ＰＬＡ：ＰＢＡＴ＝７０．０～９８．０重量％：３０．０～２．０重量％で、特に８２．５～９７．５重量％：１７．５～２．５重量％が好ましい。両外層におけるＰＬＡの配合割合が７０重量％を下回ると、フィルムの透明性が悪化する。また両外層におけるＰＢＡＴの配合割合が２．０重量％を下回ると、フィルムを折り曲げた際に、両外層と中間層との間で層間剥離を起こす可能性がある。
　尚、ＢＡＳＦ社製「エコバイオ」（登録商標）は、ＰＬＡとＰＢＡＴを含むため、当該樹脂を利用し、更にＰＬＡとＰＢＡＴの配合割合が上記範囲となるように、更にＰＬＡやＰＢＡＴも追加して使用することもできる。 The blending ratio of PLA and PBAT in the resin composition (A) is PLA: PBAT = 70.0 to 98.0% by weight: 30.0 to 2.0% by weight, and particularly 82.5 to 97.5% by weight. : 17.5 to 2.5% by weight is preferable. When the blending ratio of PLA in both outer layers is less than 70% by weight, the transparency of the film deteriorates. Further, if the compounding ratio of PBAT in both outer layers is less than 2.0% by weight, delamination may occur between both outer layers and the intermediate layer when the film is bent.
Since BASF's "Ecobio" (registered trademark) contains PLA and PBAT, the resin is used, and PLA and PBAT are further added so that the blending ratio of PLA and PBAT is within the above range. It can also be used.
［中間層］
　中間層は、ＰＢＡＴを主成分とし、ＰＬＡを副成分とする樹脂組成物Ｂからなる。中間層に用いるＰＢＡＴ、ＰＬＡは、いずれも上述した樹脂を特に限定なく用いることができる。
　樹脂組成物（Ｂ）におけるＰＬＡとＰＢＡＴの配合割合は、ＰＬＡ：ＰＢＡＴ＝２．０～２０．０重量％：９８．０～８０．０重量％で、特に４．０～１５．０重量％：９６．０～８５．０重量％が好ましい。中間におけるＰＬＡの配合割合が２．０重量％を下回ると、
フィルムを折り曲げた際に、両外層と中間層との間で層間剥離を起こす可能性がある。また中間層におけるＰＢＡＴの配合割合が８０．０重量％を下回ると、得られるフィルムの柔軟性が低下する恐れがある。
　尚、ＢＡＳＦ社製「エコバイオ」（登録商標）は、ＰＬＡとＰＢＡＴを含むため、当該樹脂を利用し、更にＰＬＡとＰＢＡＴの配合割合が上記範囲となるように、更にＰＬＡやＰＢＡＴも追加して使用することもできる。 [Middle layer]
The intermediate layer is composed of a resin composition B containing PBAT as a main component and PLA as a sub component. As PBAT and PLA used for the intermediate layer, the above-mentioned resin can be used without particular limitation.
The blending ratio of PLA and PBAT in the resin composition (B) is PLA: PBAT = 2.0 to 20.0% by weight: 98.0 to 80.0% by weight, and particularly 4.0 to 15.0% by weight. : 96.0 to 85.0% by weight is preferable. When the compounding ratio of PLA in the middle is less than 2.0% by weight,
When the film is bent, delamination may occur between both outer layers and the intermediate layer. Further, if the blending ratio of PBAT in the intermediate layer is less than 80.0% by weight, the flexibility of the obtained film may decrease.
Since BASF's "Ecobio" (registered trademark) contains PLA and PBAT, the resin is used, and PLA and PBAT are further added so that the blending ratio of PLA and PBAT is within the above range. It can also be used.
［添加剤］
　樹脂組成物（Ａ）、樹脂組成物（Ｂ）には、例えば、滑剤、酸化防止剤、紫外線吸収剤、光安定剤、帯電防止剤、顔料、染料、界面活性剤、ブロッキング防止剤、改質用樹脂などを、本発明の効果を妨げない範囲において、使用することができる。
　また、ＰＬＡとＰＢＡＴとの相溶性を改善する目的で、相溶化剤を添加することが望ましい。相溶化剤としてはカルボン酸無水物、例えば無水マレイン酸及び特に、スチレン、アクリル酸エステル及び／又はメタクリル酸エステルをベースとする前記のエポキシ基含有コポリマーである。そのエポキシ基を有する単位は、好ましくはグリシジル（メタ）アクリラートである。前記のタイプのエポキシ基含有コポリマーは、例えばＢＡＳＦ ＲｅｓｉｎｓＢ.Ｖ.から銘柄Ｊｏｎｃｒｙｌ（登録商標） ＡＤＲで販売されている。相溶化剤として特に適しているのは、例えばＪｏｎｃｒｙｌ（登録商標） ＡＤＲ　４３６８である。相溶化剤の添加量は特に限定されるものではないが、例えば、ＰＬＡとＰＢＡＴの合計１００重量部に対し０．０１～２．００重量部添加するとよい。 [Additive]
The resin composition (A) and the resin composition (B) include, for example, lubricants, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, pigments, dyes, surfactants, antiblocking agents, and modifications. A resin or the like can be used as long as the effect of the present invention is not impaired.
Further, it is desirable to add a compatibilizer for the purpose of improving the compatibility between PLA and PBAT. Examples of the compatibilizer are the above-mentioned epoxy group-containing copolymers based on carboxylic acid anhydrides such as maleic anhydride and in particular styrene, acrylic acid esters and / or methacrylic acid esters. The unit having the epoxy group is preferably glycidyl (meth) acrylate. Epoxy group-containing copolymers of the above type are sold, for example, by BASF Resins B.V. under the brand Joncryl® ADR. Particularly suitable as a compatibilizer is, for example, Joncryl® ADR 4368. The amount of the compatibilizer added is not particularly limited, but for example, 0.01 to 2.00 parts by weight may be added to a total of 100 parts by weight of PLA and PBAT.
［熱収縮性フィルム］
　また本発明の熱収縮性フィルムは、両外層が樹脂組成物Ａからなり、その間に樹脂組成物Ｂからなる中間層を備えるもので、例えば、外層（樹脂組成物Ａ）／中間層（樹脂組成物Ｂ）／外層（樹脂組成物Ａ）からなる３層構造である。また外層（樹脂組成物Ａ）／中間層（樹脂組成物Ｂ）／中間層（樹脂組成物Ａ）／中間層（樹脂組成物Ｂ）／外層（樹脂組成物Ａ）の５層構造などであってもよい。
　また樹脂組成物Ａからなる両外層と樹脂組成物Ｂからなる中間層の他に、ＰＬＡとＰＢＡＴとを、ＰＬＡ：ＰＢＡＴ＝２０重量％超～７０重量％未満：８０重量％未満～３０重量％超の割合で含む樹脂組成物Ｃからなる中間層を更に含んでいてもよい。詳しくは外層（樹脂組成物Ａ）／中間層（樹脂組成物Ｃ）／中間層（樹脂組成物Ｂ）／中間層（樹脂組成物Ｃ）／外層（樹脂組成物Ａ）や、外層（樹脂組成物Ａ）／中間層（樹脂組成物Ｃ）／中間層（樹脂組成物Ｂ）／外層（樹脂組成物Ａ）等である。 [Heat shrinkable film]
Further, the heat-shrinkable film of the present invention has both outer layers made of the resin composition A and an intermediate layer made of the resin composition B between them. For example, the outer layer (resin composition A) / intermediate layer (resin composition). It has a three-layer structure composed of a substance B) / an outer layer (resin composition A). Further, it has a five-layer structure of an outer layer (resin composition A) / intermediate layer (resin composition B) / intermediate layer (resin composition A) / intermediate layer (resin composition B) / outer layer (resin composition A). You may.
Further, in addition to both outer layers made of the resin composition A and the intermediate layer made of the resin composition B, PLA and PBAT are mixed with PLA: PBAT = more than 20% by weight to less than 70% by weight: less than 80% by weight to 30% by weight. An intermediate layer made of the resin composition C contained in a superb ratio may be further contained. Specifically, the outer layer (resin composition A) / intermediate layer (resin composition C) / intermediate layer (resin composition B) / intermediate layer (resin composition C) / outer layer (resin composition A) and outer layer (resin composition). A) / intermediate layer (resin composition C) / intermediate layer (resin composition B) / outer layer (resin composition A) and the like.
　本発明の熱収縮性フィルムの全体の厚さは、１０～３０μｍであることが望ましく、１０～２５μｍ、が望ましい。フィルム全体の厚さが１０μm未満では、強度が不十分である。また２５μｍを超えると柔軟性が低下し、更に樹脂の使用量が増加することから経済性も低下する。
　熱収縮性フィルムが、外層／中間層／外層を順に備える３層フィルムの場合、各層の厚さ割合は、外層：中間層：外層＝１：４：１～１：８：１であることが好ましい。中間層の比率が４を下回ると熱収縮性フィルムの柔軟性が低下し、また中間層の比率が８を超えると収縮特性が悪化する。また、表面層の厚さが１μｍを下回ると、熱収縮性フィルムの透明度が低下する。　 The total thickness of the heat-shrinkable film of the present invention is preferably 10 to 30 μm, preferably 10 to 25 μm. If the total thickness of the film is less than 10 μm, the strength is insufficient. Further, if it exceeds 25 μm, the flexibility is lowered and the amount of the resin used is further increased, so that the economic efficiency is also lowered.
When the heat-shrinkable film is a three-layer film including an outer layer / intermediate layer / outer layer in this order, the thickness ratio of each layer may be outer layer: intermediate layer: outer layer = 1: 4: 1 to 1: 8: 1. preferable. When the ratio of the intermediate layer is less than 4, the flexibility of the heat-shrinkable film is lowered, and when the ratio of the intermediate layer is more than 8, the shrinkage characteristics are deteriorated. Further, when the thickness of the surface layer is less than 1 μm, the transparency of the heat-shrinkable film is lowered.
　また、本発明の熱収縮性フィルムは、グリセリン中での縦方向及び横方向の収縮率が９０℃で３０％以上、１１０℃で５０％以上であることが望ましい。９０℃グリセリン中での収縮率が３０％以上、つまり低温収縮性に優れていれば、収縮包装の際のフィルム収縮温度の設定を低く、加熱時間も短く設定できるので、熱によって変質しやすい被包装物の包装に好適に利用される。１１０℃グリセリン中での収縮率はそのフィルムの最終収縮率に近い値を示しており、この値が５０％未満であると収縮包装した際にフィルムのコーナー部分が十分に収縮しないで硬い突起状になった所謂、角が発生したり、被包装体と接する部分が十分に収縮しきらないでシワが発生したりして、美麗な包装体が得られない恐れがある。 Further, it is desirable that the heat-shrinkable film of the present invention has a shrinkage rate in the longitudinal and horizontal directions in glycerin of 30% or more at 90 ° C. and 50% or more at 110 ° C. If the shrinkage rate in 90 ° C. glycerin is 30% or more, that is, if the film shrinkage is excellent at low temperature, the film shrinkage temperature at the time of shrinkage packaging can be set low and the heating time can be set short, so that the film is easily deteriorated by heat. It is suitably used for packaging packages. The shrinkage rate in 110 ° C. glycerin shows a value close to the final shrinkage rate of the film, and if this value is less than 50%, the corners of the film do not shrink sufficiently when shrink-wrapped and have a hard protrusion. There is a risk that a beautiful package cannot be obtained due to the formation of so-called corners or wrinkles due to insufficient shrinkage of the portion in contact with the packaged object.
［熱収縮性フィルムの製造方法］
　本発明の熱収縮性フィルムは、上述した樹脂組成物を、例えばインフレーション製膜法やＴダイ製膜法などを用いてフィルム状に製膜し、これをロール延伸法及び／又はテンター延伸法により、一軸延伸、あるいは二軸延伸することにより製造することができる。
　またインフレーション製膜法により製膜する際に、ブローアップ比やドロー比を大きくして延伸処理することにより製造することもできる。更にインフレーション製膜法により製膜されたチューブ状のフィルムを、チューブラー延伸法により延伸して製造することもできる。尚、本発明の熱収縮性フィルムの製造方法は、その他、従来公知の方法を採用することができる。 [Manufacturing method of heat-shrinkable film]
In the heat-shrinkable film of the present invention, the above-mentioned resin composition is formed into a film by using, for example, an inflation film forming method or a T-die film forming method, and this is formed by a roll stretching method and / or a tenter stretching method. It can be produced by uniaxial stretching or biaxial stretching.
Further, when the film is formed by the inflation film forming method, it can be produced by increasing the blow-up ratio and the draw ratio and performing the stretching treatment. Further, a tubular film formed by an inflation film forming method can be stretched and produced by a tubular stretching method. In addition, as the method for producing the heat-shrinkable film of the present invention, a conventionally known method can be adopted.
以下、実施例、比較例に基づき、本発明の効果を確認する。尚、本発明の実施例、比較例で使用した樹脂は以下のとおりである。 Hereinafter, the effect of the present invention will be confirmed based on Examples and Comparative Examples. The resins used in the examples and comparative examples of the present invention are as follows.
　次に実施例に基づき、本発明の効果を確認する。尚、各フィルムの評価は以下の方法により行った。
＜層間接着強度＞
　得られたフィルムを幅１０ｍｍの長方形に切断する。該フィルムの外層と中間層の接着強度が測定できる様、オートグラフにセットする。剥離速度５００ｍｍ／ｍｉｎにて１８０°剥離し、剥離に要する力を測定する。測定には(株)島津製作所製ＡＧＳ－５００ＮＸを用いる。尚、層間接着強度は１Ｎ／１０ｍｍを超えると、非常に良好であると判断することができる。
＜折り曲げ剥離試験＞
　得られたフィルムを折り曲げた状態で切断し、フィルム断面における外層の剥離状態をマイクロスコープで観察する。
外層の剥離が見られたものは×、見られなかったものは〇と評価する。 Next, the effect of the present invention will be confirmed based on the examples. The evaluation of each film was performed by the following method.
<Interlayer adhesive strength>
The obtained film is cut into a rectangle having a width of 10 mm. It is set in the autograph so that the adhesive strength between the outer layer and the intermediate layer of the film can be measured. Peel 180 ° at a peeling speed of 500 mm / min, and measure the force required for peeling. AGS-500NX manufactured by Shimadzu Corporation is used for the measurement. If the interlayer adhesion strength exceeds 1N / 10 mm, it can be judged that the interlayer adhesion strength is very good.
<Bending peeling test>
The obtained film is cut in a bent state, and the peeled state of the outer layer in the cross section of the film is observed with a microscope.
Those with peeling of the outer layer are evaluated as x, and those without peeling are evaluated as 〇.
＜ヘーズ＞
　得られたフィルムのヘーズをＪＩＳ　Ｋ　７１３６：２０００に準拠して測定する。測定には日本電色（株）製ＮＤＨ－４０００を用いる。尚、ヘーズは５％以下であると非常に良好であると判断することができる。
＜溶断シール強度＞
　得られたフィルムをシール温度１９０℃、シール時間０．５秒にて溶断シールし、その後１５ｍｍ幅になるようカットする。得られた試験片の溶断シール強度をＪＩＳ　Ｚ　１７１１　８．４　ヒートシール強さ試験に準じ、引張速度５００ｍｍ／ｍｉｎで測定する。測定には島津製作所（株）製ＡＧ－１　ＫＮＩＳＭＯを用いる。尚、溶断シール強度は１１Ｎ／１５ｍｍを超えると非常に良好であると判断することができる。
＜溶断シール伸び＞
　溶断シール強度を測定する際に、シール部分が破断したときのチャック間距離から求める。詳しくは、初期チャック間距離をａ、シール部分が破断した時のチャック間距離をｂとしたとき、１００×（ｂ－ａ）／ａで求める。尚、溶断シール伸びは２０％を超えると非常に良好であると判断することができる。 <Haze>
The haze of the obtained film is measured according to JIS K 7136: 2000. NDH-4000 manufactured by Nippon Denshoku Co., Ltd. is used for the measurement. It can be judged that the haze is very good when it is 5% or less.
<Fusing seal strength>
The obtained film is fused and sealed at a sealing temperature of 190 ° C. and a sealing time of 0.5 seconds, and then cut to a width of 15 mm. The fusing seal strength of the obtained test piece is measured at a tensile speed of 500 mm / min according to the JIS Z 1711 8.4 heat seal strength test. AG-1 KNISMO manufactured by Shimadzu Corporation is used for the measurement. It can be judged that the fusing seal strength is very good when it exceeds 11 N / 15 mm.
<Fusing seal elongation>
When measuring the fusing seal strength, it is obtained from the distance between chucks when the seal portion breaks. Specifically, when the initial distance between chucks is a and the distance between chucks when the seal portion is broken is b, it is calculated as 100 × (ba) / a. It can be judged that the elongation of the fusing seal is very good when it exceeds 20%.
［実施例１］
　表１に記す外層用の樹脂組成物Ａと中間層用の樹脂組成物Ｂを別々の押出機に供給し、Ｔダイ共押出法にて、外層（樹脂組成物Ａ）／中間層（樹脂組成物Ｂ）／外層（樹脂組成物Ａ）の厚さ２４０μｍの三層フィルムを得た。これを二軸延伸装置（（株）岩本製作所）にて、縦横各４倍に延伸し、厚さ１５μｍの熱収縮性フィルムを得た。
尚、各層の厚さ比は、外層：中間層：外層＝１：６：１となるように調整した。得られたフィルムの性能を表１に併せて記す。
［実施例２～６、比較例１～４］
　表１又は２に記すように樹脂組成を変更した以外は、実施例１と同様にして各フィルムを得た。得られたフィルムの評価を表１、表２に併せて記す。 [Example 1]
The resin composition A for the outer layer and the resin composition B for the intermediate layer shown in Table 1 are supplied to separate extruders, and the outer layer (resin composition A) / intermediate layer (resin composition) is subjected to the T-die coextrusion method. A three-layer film having a thickness of product B) / outer layer (resin composition A) of 240 μm was obtained. This was stretched four times in each of the vertical and horizontal directions by a biaxial stretching device (Iwamoto Seisakusho Co., Ltd.) to obtain a heat-shrinkable film having a thickness of 15 μm.
The thickness ratio of each layer was adjusted so that outer layer: intermediate layer: outer layer = 1: 6: 1. The performance of the obtained film is also shown in Table 1.
[Examples 2 to 6, Comparative Examples 1 to 4]
Each film was obtained in the same manner as in Example 1 except that the resin composition was changed as described in Table 1 or 2. The evaluations of the obtained films are also shown in Tables 1 and 2.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
 実施例１～６の熱収縮性フィルムは、いずれも層間接着強度が高く、フィルムを折り曲げても、層間剥離することがなかった。特に、両外層におけるＰＬＡ：ＰＢＡＴが、８２．５～９７．５重量％：１７．５～２．５重量％の範囲内であり、中間層におけるＰＬＡ：ＰＢＡＴが、４．０～１５．０重量％：９６．０～８５．０重量％の範囲内である実施例１～３のフィルムは、溶断シール強度も高かった。また熱収縮性フィルム全体におけるＰＬＡ：ＰＢＡＴが２５．０～３５．０重量％：７５．０～６５．０重量％の範囲内である実施例１～４のフィルムは溶断シール伸びが良好であった。溶断シール伸びが良好であると、シール部分に衝撃が加わっても、シール部が破断し難い。 The heat-shrinkable films of Examples 1 to 6 all had high interlayer adhesion strength, and even when the films were bent, delamination did not occur. In particular, the PLA: PBAT in both outer layers is in the range of 82.5 to 97.5% by weight: 17.5 to 2.5% by weight, and the PLA: PBAT in the intermediate layer is 4.0 to 15.0. The films of Examples 1 to 3 in the range of% by weight: 96.0 to 85.0% by weight also had high fusing seal strength. Further, the films of Examples 1 to 4 in which the PLA: PBAT in the entire heat-shrinkable film was in the range of 25.0 to 35.0% by weight: 75.0 to 65.0% by weight had good fusing seal elongation. rice field. If the fusing seal has good elongation, the seal portion is unlikely to break even if an impact is applied to the seal portion.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　比較例１～４のフィルムはいずれも層間接着強度が低く、折り曲げた際にフィルムの層間剥離が見られた。また比較例２のフィルムは、フィルム全体におけるＰＢＡＴの量が８０重量％を超えており、溶断シール強度が低いという問題があった。また実施例５、６、比較例４のフィルムは、熱収縮性フィルム全体におけるＰＬＡの量が４０重量％以下ではあったが、好ましい範囲（３５重量％以下）を超えており、溶断シール伸びが低かった。

  The films of Comparative Examples 1 to 4 had low interlayer adhesion strength, and delamination of the films was observed when the films were bent. Further, the film of Comparative Example 2 has a problem that the amount of PBAT in the entire film exceeds 80% by weight and the fusing seal strength is low. Further, in the films of Examples 5 and 6 and Comparative Example 4, the amount of PLA in the entire heat-shrinkable film was 40% by weight or less, but it exceeded the preferable range (35% by weight or less), and the fusing seal elongation was extended. It was low.

Claims (3)

  1. 　ポリ乳酸系樹脂を主成分とする樹脂組成物Ａからなる両外層と、脂肪族－芳香族ポリエステル系樹脂を主成分とする樹脂組成物Ｂからなる中間層と、を有する熱収縮性フィルムであって、
    　前記樹脂組成物Ａが、ポリ乳酸系樹脂と脂肪族－芳香族ポリエステル系樹脂とを、ポリ乳酸系樹脂：脂肪族－芳香族ポリエステル系樹脂＝７０．０～９８．０重量％：３０．０～２．０重量％の割合で含み、
    　前記樹脂組成物Ｂが、ポリ乳酸系樹脂と脂肪族－芳香族ポリエステル系樹脂とを、ポリ乳酸系樹脂：脂肪族－芳香族ポリエステル系樹脂＝２．０～２０．０重量％：９８．０～８０．０の割合で含むことを特徴とする熱収縮性フィルム。     A heat-shrinkable film having both outer layers made of a resin composition A containing a polylactic acid-based resin as a main component and an intermediate layer made of a resin composition B containing an aliphatic-aromatic polyester-based resin as a main component. hand,
    The resin composition A comprises a polylactic acid resin and an aliphatic-aromatic polyester resin, and a polylactic acid resin: aliphatic-aromatic polyester resin = 70.0 to 98.0% by weight: 30.0. Including at a rate of ~ 2.0% by weight,
    The resin composition B comprises a polylactic acid-based resin and an aliphatic-aromatic polyester-based resin, and the polylactic acid-based resin: aliphatic-aromatic polyester-based resin = 2.0 to 20.0% by weight: 98.0. A heat-shrinkable film characterized by containing in a proportion of ~ 80.0.
  2. 　前記樹脂組成物Ａが、ポリ乳酸系樹脂と脂肪族－芳香族ポリエステル系樹脂とを、ポリ乳酸系樹脂：脂肪族－芳香族ポリエステル系樹脂＝８２．５～９７．５重量％：１７．５～２．５重量％の割合で含み、
    　前記樹脂組成物Ｂが、ポリ乳酸系樹脂と脂肪族－芳香族ポリエステル系樹脂とを、ポリ乳酸系樹脂：脂肪族－芳香族ポリエステル系樹脂＝４．０～１５．０重量％：９６．０～８５．０の割合で含むことを特徴とする請求項１記載の熱収縮性フィルム。     The resin composition A comprises a polylactic acid-based resin and an aliphatic-aromatic polyester-based resin, and the polylactic acid-based resin: aliphatic-aromatic polyester-based resin = 82.5 to 97.5% by weight: 17.5. Including at a rate of ~ 2.5% by weight,
    The resin composition B comprises a polylactic acid-based resin and an aliphatic-aromatic polyester-based resin, and the polylactic acid-based resin: aliphatic-aromatic polyester-based resin = 4.0 to 15.0% by weight: 96.0. The heat-shrinkable film according to claim 1, wherein the film is contained in a proportion of about 85.0.
  3. 　外層／中間層／外層を順に備える３層フィルムであって、各層の厚さ割合が、外層：中間層：外層＝１：４：１～１：８：１であることを特徴とする請求項１または２記載の熱収縮性フィルム。

          A three-layer film including an outer layer / an intermediate layer / an outer layer in this order, wherein the thickness ratio of each layer is outer layer: intermediate layer: outer layer = 1: 4: 1 to 1: 8: 1. The heat-shrinkable film according to 1 or 2.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005035238A (en) * 2003-07-18 2005-02-10 Fuji Seal International Inc Heat shrinkable film and package
JP2006015720A (en) * 2004-06-01 2006-01-19 Okura Ind Co Ltd Biodegradable biaxially stretched film
JP2006088518A (en) * 2004-09-24 2006-04-06 Mitsubishi Plastics Ind Ltd Heat-shrinkable polylactic acid film
JP2007136770A (en) * 2005-11-16 2007-06-07 Tohcello Co Ltd Polylactic acid biaxially stretched laminated film and packaging bag
JP2013510231A (en) * 2009-11-09 2013-03-21 ビーエーエスエフ ソシエタス・ヨーロピア Shrink sheet manufacturing method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005035238A (en) * 2003-07-18 2005-02-10 Fuji Seal International Inc Heat shrinkable film and package
JP2006015720A (en) * 2004-06-01 2006-01-19 Okura Ind Co Ltd Biodegradable biaxially stretched film
JP2006088518A (en) * 2004-09-24 2006-04-06 Mitsubishi Plastics Ind Ltd Heat-shrinkable polylactic acid film
JP2007136770A (en) * 2005-11-16 2007-06-07 Tohcello Co Ltd Polylactic acid biaxially stretched laminated film and packaging bag
JP2013510231A (en) * 2009-11-09 2013-03-21 ビーエーエスエフ ソシエタス・ヨーロピア Shrink sheet manufacturing method

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