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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W90/00—Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
  • Y02W90/10—Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics

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)

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Citations (5)

• 2021
  • 2021-09-13 JP JP2022550554A patent/JP7759330B2/ja active Active
  • 2021-09-13 WO PCT/JP2021/033601 patent/WO2022059651A1/ja not_active Ceased

Patent Citations (5)

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