WO2024203640A1 - 延伸フィルムの製造方法 - Google Patents

延伸フィルムの製造方法 Download PDF

Info

Publication number
WO2024203640A1
WO2024203640A1 PCT/JP2024/010810 JP2024010810W WO2024203640A1 WO 2024203640 A1 WO2024203640 A1 WO 2024203640A1 JP 2024010810 W JP2024010810 W JP 2024010810W WO 2024203640 A1 WO2024203640 A1 WO 2024203640A1
Authority
WO
WIPO (PCT)
Prior art keywords
film
hydroxybutyrate
poly
heat treatment
specific direction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2024/010810
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
秀典 亀井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kaneka Corp
Original Assignee
Kaneka Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kaneka Corp filed Critical Kaneka Corp
Priority to JP2025510592A priority Critical patent/JPWO2024203640A1/ja
Publication of WO2024203640A1 publication Critical patent/WO2024203640A1/ja
Priority to US19/339,028 priority patent/US20260021641A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/07—Flat, e.g. panels
    • B29C48/08—Flat, e.g. panels flexible, e.g. films
    • 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
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
    • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B29C48/0018—Combinations of extrusion moulding with other shaping operations combined with shaping by orienting, stretching or shrinking, e.g. film blowing
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/30—Extrusion nozzles or dies
    • B29C48/305—Extrusion nozzles or dies having a wide opening, e.g. for forming sheets
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • 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
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/005—Shaping by stretching, e.g. drawing through a die; Apparatus therefor characterised by the choice of materials
    • 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
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
    • B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
    • 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
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
    • B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
    • B29C55/14—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial successively
    • 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
    • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
    • B29C71/02—Thermal after-treatment
    • 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
    • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
    • B29C71/04—After-treatment of articles without altering their shape; Apparatus therefor by wave energy or particle radiation, e.g. for curing or vulcanising preformed articles
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
    • C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • 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
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
    • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
    • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
    • B29C2035/0822—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using IR radiation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2007/00—Flat articles, e.g. films or sheets

Definitions

  • the present invention relates to a method for producing a stretched film containing a poly(3-hydroxybutyrate)-based resin.
  • microplastics which are plastics that break down and break down into tiny particles due to ultraviolet rays, adsorb harmful compounds in seawater, and are then ingested by marine organisms, resulting in the incorporation of harmful substances into the food chain.
  • biodegradable plastics are expected to combat marine pollution caused by such plastics, but a report compiled by the United Nations Environment Programme in 2015 pointed out that plastics that can be biodegraded through composting, such as polylactic acid, cannot be expected to decompose in a short period of time in the cold ocean waters, and therefore cannot be used to combat marine pollution.
  • poly(3-hydroxybutyrate) resins are attracting attention as a material that can solve the above problems, as they can biodegrade even in seawater.
  • a method of stretching a film is known as a technique for producing a thin, high-strength film.
  • a method of stretching a film is known as a technique for producing a thin, high-strength film.
  • the molten resin is cooled and solidified using a cast roll to form a roll of raw material, which is then preheated to a temperature at which it can be stretched and then stretched, allowing the stretched film to be produced continuously and with good productivity.
  • Patent Document 1 discloses a method for producing biaxially stretched films containing poly(3-hydroxybutyrate)-based resin with good productivity.
  • a stretched film made primarily of poly(3-hydroxybutyrate) resin is used as a packaging film, for example, it is heated to bond the stretched films together to seal the contents, or the ink is heated to fix the ink after it has been applied to the stretched film for printing.
  • this type of heating can cause the stretched film to shrink, distorting the seal and printing.
  • Patent Document 2 discloses that a reflective film containing an aliphatic polyester resin, an acrylic resin, and a fine powder filler is heat-treated at 90°C to 160°C after stretching in order to impart dimensional stability, but similar heat treatment of a stretched film containing a poly(3-hydroxybutyrate) resin does not sufficiently suppress thermal shrinkage.
  • the present invention aims to provide a method for producing a stretched film containing poly(3-hydroxybutyrate)-based resin that has little heat shrinkage.
  • the present invention provides a method for producing a stretched film containing poly(3-hydroxybutyrate)-based resin that has little heat shrinkage.
  • 1 is a diagram for explaining the concept of the amount of relaxation of a film.
  • the poly(3-hydroxybutyrate)-based resin is an aliphatic polyester-based resin that can be produced from a microorganism, and is a polyester resin having 3-hydroxybutyrate as a repeating unit.
  • the poly(3-hydroxybutyrate)-based resin may be a poly(3-hydroxybutyrate) having only 3-hydroxybutyrate as a repeating unit, or may be a copolymer of 3-hydroxybutyrate and another hydroxyalkanoate.
  • the poly(3-hydroxybutyrate)-based resin may be a mixture of a homopolymer and one or more types of copolymers, or a mixture of two or more types of copolymers.
  • poly(3-hydroxybutyrate) resins include poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [hereinafter, may be referred to as P3HB3HH], poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [hereinafter, may be referred to as P3HB3HV], poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [hereinafter, may be referred to as P3HB4HB], poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate), etc.
  • poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) are preferred because they are easy to produce industrially.
  • composition ratio of the repeating units it is possible to change the melting point and degree of crystallinity, and thus physical properties such as Young's modulus and heat resistance, making it possible to impart physical properties between those of polypropylene and polyethylene.
  • poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is preferred.
  • poly(3-hydroxybutyrate)-based resins which have the property of being easily thermally decomposed when heated to 180°C or higher
  • poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is preferred from the viewpoints that it can lower the melting point and enable molding processing at low temperatures.
  • the average content ratio of each monomer unit in all monomer units constituting the poly(3-hydroxybutyrate)-based resin can be determined by a method known to those skilled in the art, for example, the method described in paragraph [0047] of WO 2013/147139.
  • the average content ratio means the molar ratio of each monomer unit in all monomer units constituting the poly(3-hydroxybutyrate)-based resin, and when the poly(3-hydroxybutyrate)-based resin is a mixture of two or more poly(3-hydroxybutyrate)-based resins, it means the molar ratio of each monomer unit contained in the entire mixture.
  • the poly(3-hydroxybutyrate) resin may be a mixture of at least two types of poly(3-hydroxybutyrate) resins that differ from each other in the type of constituent monomers and/or the content ratio of the constituent monomers.
  • the weight average molecular weight of the entire poly(3-hydroxybutyrate) resin is not particularly limited, but from the viewpoint of achieving both strength and productivity of the stretched film, it is preferably 200,000 to 2,000,000 g/mol, more preferably 250,000 to 1,500,000 g/mol, and even more preferably 300,000 to 1,000,000 g/mol.
  • the weight-average molecular weight of poly(3-hydroxybutyrate) resins can be measured in polystyrene equivalent terms using gel permeation chromatography (Shimadzu Corporation HPLC GPC system) with a chloroform solution.
  • a column suitable for measuring weight-average molecular weights can be used as the column for the gel permeation chromatography.
  • the method for producing poly(3-hydroxybutyrate) resins is not particularly limited, and may be a production method by chemical synthesis or a production method using microorganisms. Among these, production methods using microorganisms are preferred. Known methods can be applied to the production method using microorganisms.
  • known bacteria that produce copolymers of 3-hydroxybutyrate and other hydroxyalkanoates include Aeromonas caviae, which produces P3HB3HV and P3HB3HH, and Alcaligenes eutrophus, which produces P3HB4HB.
  • Aeromonas caviae which produces P3HB3HV and P3HB3HH
  • Alcaligenes eutrophus which produces P3HB4HB.
  • the poly(3-hydroxybutyrate) resin may be an unmodified resin, or an unmodified poly(3-hydroxybutyrate) resin may be modified with a raw material that reacts with the resin, such as a peroxide (hereinafter referred to as the "modifying raw material").
  • a raw material that reacts with the resin such as a peroxide (hereinafter referred to as the "modifying raw material").
  • a film raw material containing a poly(3-hydroxybutyrate) resin that has already been reacted with a modifying raw material may be molded into a film, or a film raw material containing an unmodified poly(3-hydroxybutyrate) resin and a modifying raw material may be reacted with the modifying raw material during molding.
  • the entire resin may be reacted with the modifying raw material, or a portion of the resin may be reacted with the modifying raw material to obtain a modified resin, and the remaining unmodified resin may then be added to the modified resin.
  • the raw material for modification is not particularly limited as long as it is a compound that can react with the poly(3-hydroxybutyrate)-based resin, but organic peroxides are preferably used because of their ease of handling and the ease of controlling the reaction with the poly(3-hydroxybutyrate)-based resin.
  • the organic peroxides include, for example, diisobutyl peroxide, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, bis(4-t-butylcyclohexyl) peroxydicarbonate, bis(2-ethylhexyl) peroxydicarbonate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di(3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, 1,1,3,3-tetramethylbuty
  • the organic peroxide may be used in various forms, such as solid or liquid, and may be in liquid form diluted with a diluent or the like.
  • organic peroxides in a form that can be easily mixed with the poly(3-hydroxybutyrate)-based resin are preferred because they can be more uniformly dispersed in the poly(3-hydroxybutyrate)-based resin and are more likely to suppress localized modification reactions in the resin composition.
  • the content of poly(3-hydroxybutyrate) resin in the stretched film may be 50% by weight or more, 55% by weight or more, 60% by weight or more, 70% by weight or more, or 80% by weight or more. There is no upper limit to the content of poly(3-hydroxybutyrate) resin, and it may be 100% by weight or less.
  • the stretched film may contain additives that can be used with the poly(3-hydroxybutyrate) resin to the extent that the effect of the invention is not impaired.
  • additives include colorants such as pigments and dyes, odor absorbents such as activated carbon and zeolite, fragrances such as vanillin and dextrin, fillers, plasticizers, antioxidants, weather resistance improvers, UV absorbers, crystal nucleating agents, lubricants, release agents, water repellents, antibacterial agents, and sliding improvers.
  • the film may contain only one type of additive, or may contain two or more types. The content of these additives can be appropriately set by a person skilled in the art depending on the purpose of use. Even if the poly(3-hydroxybutyrate) resin contains these additives, its melting point is approximately the same as the melting point of the poly(3-hydroxybutyrate) resin.
  • crystal nucleating agent examples include polyhydric alcohols such as pentaerythritol, galactitol, and mannitol; orotic acid, aspartame, cyanuric acid, glycine, zinc phenylphosphonate, and boron nitride.
  • pentaerythritol is preferred because of its particularly excellent effect of promoting the crystallization of poly(3-hydroxybutyrate)-based resins.
  • One type of crystal nucleating agent may be used, or two or more types may be used, and the ratio of use can be appropriately adjusted depending on the purpose.
  • the amount of the crystal nucleating agent used is not particularly limited, but is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, and even more preferably 0.7 to 1.5 parts by weight, per 100 parts by weight of the total amount of poly(3-hydroxybutyrate) resin.
  • lubricant examples include behenamide, oleamide, erucamide, stearamide, palmitamide, N-stearylbehenamide, N-stearylerucamide, ethylenebisstearamide, ethylenebisoleamide, ethylenebiserucamide, ethylenebislauramide, ethylenebiscapricamide, p-phenylenebisstearamide, and polycondensates of ethylenediamine, stearic acid, and sebacic acid.
  • behenamide or erucamide is preferred because of its particularly excellent lubricant effect on poly(3-hydroxybutyrate)-based resins.
  • One type of lubricant may be used, or two or more types may be used, and the ratio of use can be appropriately adjusted depending on the purpose.
  • the amount of lubricant used is not particularly limited, but is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, and even more preferably 0.1 to 1.5 parts by weight, per 100 parts by weight of the total amount of poly(3-hydroxybutyrate) resin.
  • the filler may be either an inorganic filler or an organic filler, or both may be used in combination.
  • the inorganic filler is not particularly limited, but examples thereof include silicates, carbonates, sulfates, phosphates, oxides, hydroxides, nitrides, and carbon black. Only one type of inorganic filler may be used, or two or more types may be used in combination.
  • the amount of the filler is not particularly limited, but is preferably 1 to 100 parts by weight, more preferably 3 to 80 parts by weight, even more preferably 5 to 70 parts by weight, and even more preferably 10 to 60 parts by weight, per 100 parts by weight of the total amount of the poly(3-hydroxybutyrate) resin.
  • the stretched film does not have to contain a filler.
  • plasticizer examples include glycerin ester compounds, citrate compounds, sebacic acid ester compounds, adipate compounds, polyether ester compounds, benzoic acid ester compounds, phthalic acid ester compounds, isosorbide ester compounds, polycaprolactone compounds, and dibasic acid ester compounds.
  • glycerin ester compounds, citrate compounds, sebacic acid ester compounds, and dibasic acid ester compounds are preferred because of their particularly excellent plasticizing effect on poly(3-hydroxyalkanoate) resins.
  • the glycerin ester compounds include glycerin diacetomonolaurate.
  • citrate compounds include acetyl tributyl citrate.
  • sebacic acid ester compounds examples include dibutyl sebacate.
  • dibasic acid ester compounds examples include benzyl methyl diethylene glycol adipate.
  • the plasticizer may be used alone or in combination of two or more kinds, and the ratio of use can be appropriately adjusted depending on the purpose.
  • the amount of plasticizer used is not particularly limited, but is preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, and even more preferably 3 to 10 parts by weight, per 100 parts by weight of the total amount of poly(3-hydroxybutyrate) resin.
  • the stretched film does not have to contain a plasticizer.
  • the stretched film may contain other resins besides the poly(3-hydroxybutyrate)-based resin, so long as the effects of the invention are not impaired.
  • other resins include aliphatic polyester-based resins such as poly(3-hydroxypropionate), poly(4-hydroxybutyrate), polybutylene succinate adipate, polybutylene succinate, polycaprolactone, and polylactic acid, and aliphatic aromatic polyester-based resins such as polybutylene adipate terephthalate (PBAT), polybutylene sebate terephthalate, and polybutylene azelate terephthalate. Only one type of other resin may be contained, or two or more types may be contained.
  • PBAT polybutylene adipate terephthalate
  • PBAT polybutylene sebate terephthalate
  • polybutylene azelate terephthalate Only one type of other resin may be contained, or two or more types may be contained.
  • the amount of the other resin is not particularly limited, but may be 100 parts by weight or less, 80 parts by weight or less, 70 parts by weight or less, 50 parts by weight or less, 30 parts by weight or less, 20 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less, relative to 100 parts by weight of the poly(3-hydroxybutyrate) resin.
  • the lower limit of the amount of the other resin is not particularly limited, and may be 0 parts by weight or more.
  • the lower limit may be 10 parts by weight or more, 20 parts by weight or more, 50 parts by weight or more, or 65 parts by weight or more per 100 parts by weight of the poly(3-hydroxybutyrate)-based resin.
  • the upper limit may be less than 100 parts by weight per 100 parts by weight of the poly(3-hydroxybutyrate)-based resin.
  • the method of forming it into a film is not particularly limited, and a known manufacturing method can be appropriately used.
  • Specific examples include an inflation molding method, a T-die extrusion molding method using an extruder equipped with a T-die, a calendar molding method, and a rolling method.
  • the inflation molding method or the T-die extrusion molding method is preferable because it can produce a strip-shaped film with good productivity.
  • a single screw extruder also called a single screw extruder
  • a twin screw extruder, etc. can be appropriately used as the extruder.
  • the molding temperature is not particularly limited as long as it is a temperature at which the resin can be properly melted, but is preferably, for example, from (melting point of poly(3-hydroxybutyrate) resin)°C to (melting point of poly(3-hydroxybutyrate) resin + 50°C), more preferably from (melting point of poly(3-hydroxybutyrate) resin)°C to (melting point of poly(3-hydroxybutyrate) resin + 30°C), and even more preferably from (melting point of poly(3-hydroxybutyrate) resin)°C to (melting point of poly(3-hydroxybutyrate) resin + 20°C).
  • the molding temperature here refers to the resin temperature from the extruder to the time it is discharged from the die.
  • the resin temperature can generally be measured, for example, by a thermometer installed in the adapter.
  • the inflation molding method is a molding method in which a molten resin is extruded into a tube shape from an extruder equipped with a cylindrical die at the tip, and immediately after that, gas is blown into the tube to inflate it into a balloon shape to form a film.
  • the inflation molding is not particularly limited, but can be performed, for example, using a general inflation molding machine used when molding a thermoplastic resin into a film.
  • a typical inflation molding machine is one in which a cylindrical die is attached to a single-screw extruder.
  • the single-screw extruder may be any machine that melts and kneads the input raw resin and obtains a constant discharge while maintaining the raw resin at the desired temperature.
  • extruders equipped with mixing elements are preferred from the viewpoint of kneading properties.
  • structure of the cylindrical die but a spiral mandrel die is preferred, as it produces fewer welds and is easy to obtain uniform thickness.
  • an air ring that is blown from the outside of the bubble can be used to solidify the extruded molten resin and stabilize the bubble.
  • the most suitable air ring blowing structure is a slit type that has multiple annular slits through which air is blown out, and the chambers between each slit promote bubble stabilization.
  • the blow-up ratio (hereinafter sometimes referred to as BUR) in inflation molding is the value obtained by dividing the circumferential length of the bubble cross section by the diameter of the die.
  • the lower limit of BUR is preferably 1.5 times or more, more preferably 1.7 times or more, even more preferably 1.9 times or more, and particularly preferably 2 times or more.
  • the upper limit of BUR is preferably 5.5 times or less, more preferably 4.5 times or less, even more preferably 4.0 times or less, and particularly preferably 3.5 times or less.
  • the T-die extrusion molding method is a molding method in which a resin molten by an extruder is extruded from a slit-shaped discharge port onto a cast roll in a film shape to form a film.
  • the T-die is not particularly limited, and any known T-die can be used as appropriate.
  • the T-die is preferably one having a discharge port shaped to extrude a film-shaped raw material, but the shape is not particularly limited.
  • the shape of the discharge port is also not particularly limited.
  • a film-like raw material is extruded from the discharge port of the T-die.
  • the shape of the raw material needs to be film-like, and there are no particular limitations on its thickness or width.
  • the thickness is preferably approximately 20 ⁇ m to 600 ⁇ m, as this reduces thickness unevenness and allows for easy cooling after extrusion.
  • the melt viscosity of the raw material extruded from the outlet of the T-die is not particularly limited, but it is preferably 1500 Pa ⁇ sec or less, as this reduces thickness unevenness and prevents the occurrence of die lines.
  • the melt viscosity can be measured according to a known method.
  • the take-up speed in inflation molding and T-die extrusion molding is determined by the film thickness, width, and resin discharge amount, but can be adjusted within a range that maintains bubble stability. Generally, 1 to 100 m/min is preferable.
  • the thickness of the film before stretching is not particularly limited, and may be set appropriately taking into consideration the desired thickness of the stretched film, the stretching ratio, strength, etc. For example, 20 to 600 ⁇ m is preferable, 40 to 500 ⁇ m is more preferable, and 50 to 300 ⁇ m is even more preferable.
  • the thickness of the film can be measured using a vernier caliper.
  • the method is not particularly limited as long as the film can be stretched in a range in which stretching is possible, and any known production method can be appropriately used.
  • the stretching direction in the stretching process is not particularly limited, and the film can be stretched in any direction in the plane direction of the film.
  • the stretching direction may be either the MD direction or the TD direction of the film, or both the MD direction and the TD direction. Stretching in either the MD direction or the TD direction is called uniaxial stretching, and stretching in both the MD direction and the TD direction is called biaxial stretching.
  • the MD direction is also called the machine direction, flow direction, or longitudinal direction.
  • the TD direction is perpendicular to the MD direction, and is also called the perpendicular direction or width direction.
  • Stretching a film in the stretching direction means pulling the film in the stretching direction.
  • a method of stretching is used in which pressure is applied in the thickness direction of the film, such as roll rolling in which the film is sandwiched between two rolls, the film is likely to adhere to the rolling rolls, which may reduce the productivity of the stretched film.
  • the film can be stretched by gripping the ends and pulling them in the stretching direction.
  • a roll longitudinal stretching machine can be used to stretch the film in the MD direction by varying the rotation speed of the rolls that transport the film.
  • the stretch ratio in the MD direction can be determined by the ratio of the rotation speed of the rolls after stretching to the rotation speed of the rolls before stretching.
  • the film When stretching a film in the TD direction while it is being transported continuously, the film can be stretched in the TD direction by, for example, clamping both widthwise ends of the film using a transverse stretching machine such as a clip-type tenter and pulling it in the TD direction.
  • the stretch ratio in the TD direction can be determined by the ratio of the distance between both widthwise ends of the clamped film after stretching to the distance between both widthwise ends of the film clamped before stretching.
  • the stretching ratio achieved in the process of stretching the molded film in a specific direction is not particularly limited, but is preferably 1.1 times or more, more preferably 1.3 times or more, even more preferably 1.5 times or more, and particularly preferably 2 times or more. There is no particular upper limit and it may be determined appropriately, but it may be, for example, 8 times or less, 7 times or less, 5 times or less, or 3 times or less.
  • the stretching ratio can be adopted for each of the MD direction and the TD direction.
  • the stretching temperature is not particularly limited as long as the film can be stretched appropriately, and can be changed according to the mechanical strength, surface properties, thickness accuracy, etc. required for the stretched film to be produced.
  • the stretching temperature is preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 60°C or higher.
  • the upper limit is sufficient as long as it is equal to or lower than the melting point of the poly(3-hydroxybutyrate) resin, and is preferably 150°C or lower, more preferably 145°C or lower, and even more preferably 140°C or lower. If the stretching temperature is within the above temperature range, the thickness unevenness of the resulting stretched film can be reduced, and furthermore, mechanical properties such as elongation, tear propagation strength, and fatigue resistance can be improved. Furthermore, problems such as the film sticking to the roll can be prevented.
  • the stretching temperature here refers to the temperature of the film during stretching.
  • the stretching temperature can generally be measured by measuring the temperature of the film itself or the ambient temperature near the film using an infrared thermometer, thermo label, thermocouple, etc.
  • the means for adjusting the film temperature during stretching is not particularly limited, but examples include non-contact heating methods such as a method in which hot air heated to within the above temperature range is applied to the film being stretched, a method in which the film is heated while being stretched using an auxiliary heating means such as an infrared heater, and a method in which the film is stretched in a heating furnace whose temperature is adjusted to within the above temperature range; and contact heating methods such as a method in which the film is brought into contact with a roll heated to within the above temperature range. These may be used alone or in combination.
  • hot air may be applied to the film between the upstream stretching roll and the downstream stretching roll in the MD direction.
  • a floating heating method as a method for applying hot air heated to within the above temperature range to the film being stretched.
  • Floating heating is a method in which hot air is blown onto both sides of the film from upper and lower nozzles to heat it. Multiple upper nozzles and multiple lower nozzles are arranged alternately toward the film surface, and the film can be heated by the hot air blown out from each of the upper and lower nozzles without the film coming into contact with either the upper or lower nozzles.
  • the film surface and inside can be heated to the same temperature in a short period of time, making it possible to stretch the entire film uniformly.
  • the infrared rays to be irradiated can be electromagnetic waves in the general infrared range, and can be any of the following: near infrared: wavelength 0.74 ⁇ m to 1.5 ⁇ m; mid infrared: wavelength 1.5 ⁇ m to 3.0 ⁇ m; far infrared: wavelength 3.0 ⁇ m to 1 mm.
  • the upstream stretching roll of the two adjacent stretching rolls may be heated to within the above temperature range.
  • the stretching temperature i.e., the temperature of the film during stretching, can be controlled by setting the temperature of the rolls to the desired stretching temperature.
  • the order of stretching is MD followed by TD.
  • a means of adjusting the film temperature during stretching it is preferable to use a method in which the film is brought into contact with a roll heated to within the above temperature range when stretching in the MD direction, and a non-contact heating method in which a heating tool heated to within the above temperature range does not come into contact with the film when stretching in the TD direction.
  • the stretched film is heated in a specific direction with a specific amount of relaxation.
  • Relaxation in a specific direction refers to relaxation in the direction of stretching.
  • the crystal orientation in that specific direction is strong, and a stretched film produced without the heat treatment process of the present disclosure has particularly large heat shrinkage in that specific direction, whereas a stretched film produced through the heat treatment process of the present disclosure has sufficiently small heat shrinkage in that specific direction.
  • relaxation refers to reducing the film dimension in a specific stretched direction in order to remove the stress in the stretched direction that exists in the film.
  • the film dimension refers to the distance between two points in an arbitrarily specified film plane, and may be the distance from one end of the film to the other end.
  • the stretched film of the present disclosure is a strip-shaped film
  • the film dimension in the MD direction may be the distance between two points in the MD direction in an arbitrarily specified film plane
  • the film dimension in the TD direction may be the distance between both ends of the film in the width direction.
  • the film dimension is the straight-line distance between two points in an arbitrarily specified film plane, and may be the straight-line distance from one end of the film to the other end, and in particular, the film dimension in the TD direction may be the straight-line distance between both ends of the film in the width direction.
  • the film dimensions in the MD direction can be adjusted by varying the rotation speed of the two adjacent rolls.
  • the film dimensions in the TD direction can be adjusted by clamping both widthwise ends of the film using a transverse stretching machine such as a clip-type tenter and changing the distance between the clamps.
  • the amount of relaxation [%] in the MD direction during the heat treatment step can be calculated by the following formula (i-i), and the amount of relaxation [%] in the TD direction can be calculated by the following formula (i-ii).
  • Relaxation amount in MD direction [%] ⁇ (rotation speed of the upstream roll of two adjacent rolls) ⁇ (rotation speed of the downstream roll of two adjacent rolls) ⁇ /(rotation speed of the upstream roll of two adjacent rolls) ⁇ 100 (i ⁇ i)
  • Relaxation amount in TD direction [%] ⁇ (distance between both ends of the film in the width direction before heat treatment) ⁇ (distance between both ends of the film in the width direction during heat treatment) ⁇ /(distance between both ends of the film in the width direction before heat treatment) ⁇ 100 (i ⁇ ii)
  • the stretching process if biaxial stretching is performed, it is preferable to relax in either the MD or TD direction, whichever was last stretched. Specifically, for example, if a film is stretched in the MD direction and then stretched in the TD direction, after stretching in the TD direction, the crystal orientation is stronger in the TD direction, so by heating to a specific temperature range with a specific amount of relaxation in the TD direction, a stretched film containing a poly(3-hydroxybutyrate) resin with little heat shrinkage in either the MD or TD direction can be obtained.
  • the amount of relaxation in the specific direction may be 9-50%, preferably 9-40%, more preferably 9-30%, and even more preferably 9-20%. If the amount of relaxation is less than 9%, the amount of heat shrinkage of the resulting stretched film in the specific direction cannot be sufficiently suppressed, and if it is more than 50%, slack will occur in the film during heat treatment, and not only will slack remain in the resulting stretched film after heat treatment, but the film may also come into contact with the manufacturing equipment, including the heating tool, and break, making it impossible to produce the stretched film with good productivity.
  • before heat treatment in the formula (i) above means “before preliminary heat treatment”
  • film dimensions in a specific direction before heat treatment in the formula (i) above can be read as “film dimensions in a specific direction before preliminary heat treatment”.
  • the heat treatment may be performed two or more times, and in that case, it is preferable to increase the amount of relaxation in the specific direction stepwise. This is because the heat shrinkage in the specific direction stretched in the process of stretching the film can be particularly reduced.
  • it is preferable to make the difference between the nth and n-1th relaxation amounts larger than the difference between the n-1th and n-2th relaxation amounts specifically, for example, it is preferable to make the difference between the 2nd and 1st relaxation amounts larger than the 1st relaxation amount, and the difference between the 3rd and 2nd relaxation amounts larger than the difference between the 2nd and 1st relaxation amounts. This is explained using a formula as follows.
  • the amount of relaxation Rn in the specific direction in the nth heat treatment is specifically expressed as the following formula (iii).
  • Relaxation amount Rn [%] ⁇ (film dimension in a specific direction before heat treatment) ⁇ (film dimension in a specific direction during the nth heat treatment) ⁇ /(film dimension in a specific direction before heat treatment) ⁇ 100 (iii)
  • the heat treatment includes a step of setting the amount of relaxation in the specific direction represented by the formula to R1 and then to R2, and it is preferable that the amounts of relaxation R1 and R2 satisfy 9% ⁇ R1 ⁇ 50%, 9% ⁇ R2 ⁇ 50%, and R1 ⁇ R2-R1. It is even more preferable that R2 satisfies 9% ⁇ R2 ⁇ 30%.
  • Figure 1 is a diagram explaining the concept of the amount of relaxation of the film, and shows an example in which the heat treatment process is performed twice.
  • the filled arrows in Figure 1 indicate the MD direction of the film
  • a and B indicate the process of stretching in the TD direction
  • B and C indicate the first heat treatment process
  • CD indicates the second heat treatment process, with steps A to D being performed in a continuous process.
  • W1 indicates the film dimension in a specific direction before heat treatment (after stretching in Figure 1)
  • W2 indicates the film dimension during the first heat treatment
  • W3 indicates the film dimension during the second heat treatment.
  • the amount of relaxation R1 [%] during the first heat treatment can be calculated as (W1-W2)/W1 x 100
  • the amount of relaxation R2 [%] during the second heat treatment can be calculated as (W1-W3)/W1 x 100.
  • the means for heating the film in the heat treatment is not particularly limited as long as it is a non-contact heating method. Examples include a method of applying hot air heated to within the above temperature range to the film, a method of heating the film using an auxiliary heating means such as an infrared heater, and a method of heating the film by placing it in a heating furnace whose temperature is adjusted to within the above temperature range. These methods may be used alone or in combination.
  • the film temperature is easily increased to a high temperature, the temperature range can be easily adjusted to be between (melting point of poly(3-hydroxybutyrate) resin - 40) °C or higher and (melting point of poly(3-hydroxybutyrate) resin) °C or lower, and the problem of the film sticking to the heating tool can be avoided.
  • the method of applying hot air heated to within the above temperature range to the film is a method of applying hot air heated to a temperature range of (melting point of poly(3-hydroxybutyrate)-based resin -40)°C or more and (melting point of poly(3-hydroxybutyrate)-based resin)°C or less to the film, and it is preferable to use a floating type heating method.
  • the method of heating the film using an infrared heater is a method of using an infrared heater to heat the film to the specified temperature range, and the infrared rays irradiated can be the same as those used when stretching the film.
  • the stretched film is heated to a temperature between (melting point of poly(3-hydroxybutyrate)-based resin -40)°C and (melting point of poly(3-hydroxybutyrate)-based resin)°C. If the temperature is lower than (melting point of poly(3-hydroxybutyrate)-based resin -40)°C, the amount of heat shrinkage of the resulting stretched film in the specific direction increases, and if the temperature is higher than (melting point of poly(3-hydroxybutyrate)-based resin)°C, the crystal orientation obtained by stretching is lost, and the mechanical strength of the resulting stretched film may decrease, or the stretched film may melt and break.
  • the film temperature during the heat treatment process is preferably from (melting point of poly(3-hydroxybutyrate) resin - 40) °C to (melting point of poly(3-hydroxybutyrate) resin) °C, more preferably from (melting point of poly(3-hydroxybutyrate) resin - 40) °C to (melting point of poly(3-hydroxybutyrate) resin - 10) °C, and even more preferably from (melting point of poly(3-hydroxybutyrate) resin - 40) °C to (melting point of poly(3-hydroxybutyrate) resin - 20) °C. This can particularly reduce the risk of the film breaking due to melting of the resin.
  • the film temperature in the heat treatment step is preferably (melting point of poly(3-hydroxybutyrate) resin - 40) ° C or more and (melting point of poly(3-hydroxybutyrate) resin) ° C or less, more preferably (melting point of poly(3-hydroxybutyrate) resin - 30) ° C or more and (melting point of poly(3-hydroxybutyrate) resin) ° C or less, and even more preferably (melting point of poly(3-hydroxybutyrate) resin - 20) ° C or more and (melting point of poly(3-hydroxybutyrate) resin) ° C or less.
  • the heat treatment includes a process of bringing the film to temperature T1 and then to temperature T2, and the temperatures T1 and T2 satisfy the following formula: It is also particularly preferable to include a process of bringing the amount of relaxation in the specific direction represented by the formula to R1 and then to R2, and to bring the film to temperature T1 at the relaxation amount R1 and to bring the film to temperature T2 at the relaxation amount R2 under the conditions that the relaxation amounts R1 and R2 satisfy 9% ⁇ R1 ⁇ 50%, 9% ⁇ R2 ⁇ 50%, and R1 ⁇ R2-R1. (melting point of poly(3-hydroxybutyrate)-based resin - 40) ° C. ⁇ T1 ⁇ T2 ⁇ (melting point of poly(3-hydroxybutyrate)-based resin) ° C. or less
  • the melting point of poly(3-hydroxybutyrate) resin refers to the apex temperature of the melting point peak in the DSC curve obtained by differential scanning calorimetry. Details of differential scanning calorimetry are described in the Examples section.
  • the heating time in the heat treatment step is not particularly limited, but from the viewpoint of productivity, for example, 1 to 180 seconds is preferable, 1 to 30 seconds is more preferable, and 1 to 10 seconds is even more preferable.
  • the method may include a pre-heat treatment step prior to the heat treatment step.
  • the pre-heat treatment refers to a treatment in which the stretched film is heated to a temperature of (melting point of poly(3-hydroxybutyrate)-based resin -40)°C or higher and (melting point of poly(3-hydroxybutyrate)-based resin)°C or lower by a non-contact heating method with a relaxation amount in the specific direction of 0% or higher and lower than 9% as represented by the following formula (ii).
  • the pre-heat treatment step it is possible to particularly reduce heat shrinkage in the specific direction stretched in the film stretching step. Also, it is possible to further reduce the risk of film breakage.
  • Relaxation amount [%] ⁇ (film dimension in a specific direction before preliminary heat treatment) ⁇ (film dimension in a specific direction during preliminary heat treatment) ⁇ /(film dimension in a specific direction before preliminary heat treatment) ⁇ 100 (ii)
  • the amount of relaxation in the MD direction [%] can be calculated by the following formula (ii-i), and the amount of relaxation in the TD direction [%] can be calculated by the following formula (ii-ii).
  • Relaxation amount in MD direction [%] ⁇ (rotation speed of the upstream roll of two adjacent rolls) ⁇ (rotation speed of the downstream roll of two adjacent rolls) ⁇ /(rotation speed of the upstream roll of two adjacent rolls) ⁇ 100 (ii ⁇ i)
  • Relaxation amount in TD direction [%] ⁇ (distance between both ends of the film in the width direction before preliminary heat treatment) ⁇ (distance between both ends of the film in the width direction during preliminary heat treatment) ⁇ /(distance between both ends of the film in the width direction before preliminary heat treatment) ⁇ 100 (ii ⁇ ii)
  • the amount of relaxation in the specific direction represented by formula (ii) during the preliminary heat treatment may be 0% or more and less than 9%, but is preferably 5% or less, more preferably 3% or less, even more preferably 1% or less, and most preferably 0%.
  • the means for heating the film in the preliminary heat treatment is not particularly limited as long as it is a non-contact heating method, and may be the same as the means for heating the film in the heat treatment.
  • the preferred ranges of film temperature and heating time in the preliminary heat treatment are the same as the preferred ranges of film temperature and heating time in the heat treatment step.
  • the amount of heat shrinkage in the stretching direction is preferably less than 10%, more preferably 8% or less, and even more preferably 6% or less.
  • the manufacturing method of the present disclosure may include a step of cooling the film after the step of heat-treating the film.
  • the film temperature in the film cooling step may be 100°C or less, and is preferably 50°C or more and 90°C or less.
  • the film temperature can be lowered to a temperature lower than the heat treatment temperature, there are no particular limitations on the means for doing so, but examples include a method using the non-contact heating method with the temperature regulated to 100°C or less, preferably 50°C or more and 90°C or less.
  • a continuous process refers to obtaining a stretched film by sequentially carrying out the steps from melting the film raw material in an extruder, forming it into a film, to stretching the formed film, to heat-treating the stretched film, and further up to cooling the film as necessary.
  • the thickness of the stretched film is not particularly limited and may be appropriately set to a desired thickness. From the viewpoints of the uniform thickness, appearance, strength, lightness, etc. of the film, the thickness is preferably 10 to 200 ⁇ m, more preferably 15 to 150 ⁇ m, and even more preferably 20 to 100 ⁇ m. The thickness of the film can be measured using a vernier caliper.
  • the stretched film disclosed herein is thin yet strong, making it suitable for use as a packaging film, for example, packaging films for food products that require heat sealability.
  • a method for producing a stretched film containing a poly(3-hydroxybutyrate)-based resin comprising the steps of: A step of melting the film raw material containing the poly(3-hydroxybutyrate)-based resin in an extruder and then forming it into a film; stretching the formed film in a specific direction; heat-treating the stretched film; the heat treatment is a treatment in which the stretched film is heated to a temperature of (melting point of poly(3-hydroxybutyrate)-based resin ⁇ 40)° C. or higher and (melting point of poly(3-hydroxybutyrate)-based resin)° C.
  • a step of pre-heat treating is included before the step of heat treating,
  • the heat treatment includes a step of changing the relaxation amount in the specific direction represented by the formula to R2 after R1, 10.
  • the heat treatment includes a treatment of the film at a temperature T1 and then at a temperature T2, and the temperatures T1 and T2 satisfy the following formula: (melting point of poly(3-hydroxybutyrate)-based resin - 40) ° C ⁇ T1 ⁇ T2 ⁇ (melting point of poly(3-hydroxybutyrate)-based resin) ° C or less [Item 13]
  • the heat treatment includes a step of changing the relaxation amount in the specific direction represented by the formula to R2 after R1, the relaxation amounts R1 and R2 satisfy 9% ⁇ R1 ⁇ 50%, 9% ⁇ R2 ⁇ 50%, and R1 ⁇ R2 ⁇ R1, Item 13.
  • A-2: P3HB3HH (average content ratio 3HB/3HH 71.8/28.2 (mol%/mol%), glass transition temperature is 1°C) Produced in accordance with the method described in Example 9 of WO 2019/142845, and adjusted to a weight average molecular weight of 660,000 g/mol by treatment with an aqueous sodium hydroxide solution.
  • A-4: P3HB3HH (average content ratio 3HB/3HH 94/6 (mol%/mol%), glass transition temperature is 6°C) It was produced in accordance with the method described in Example 1 of WO 2019/142845, and the weight average molecular weight was adjusted to 400,000 g/mol by treatment with an aqueous sodium hydroxide solution.
  • Crystal nucleating agent C-1 Pentaerythritol (manufactured by Mitsubishi Chemical Corporation, NeuRizer P)
  • Resin pellet P-1 As poly(3-hydroxybutyrate)-based resins, 30 parts by weight of A-1, 30 parts by weight of A-2, 10 parts by weight of A-3, and 30 parts by weight of A-4 were used, and 0.5 parts by weight of B-1 as a lubricant and 1.0 parts by weight of C-1 as a crystal nucleating agent were dry-blended with respect to a total of 100 parts by weight.
  • the obtained dry blend was charged into a hopper of a ⁇ 26 mm same-rotation twin-screw extruder with a cylinder temperature and a die temperature set to 150°C, melt-kneaded, extruded into strands from the die, passed through a water tank filled with hot water at 45°C to solidify the strands, and cut with a pelletizer to obtain resin pellets P-1.
  • the melting point of the resin pellets P-1 was 153°C.
  • Resin pellet P-2 Resin pellets P-2 were obtained in the same manner as resin pellets P-1, except that the dry blend was prepared by dry blending 60 parts by weight of A-3, 40 parts by weight of A-5, a total of 100 parts by weight of poly(3-hydroxybutyrate)-based resins, and 0.5 parts by weight of B-1 as a lubricant.
  • the melting point of resin pellets P-2 was 143°C.
  • Weight average molecular weight The weight average molecular weight of the resin was measured in terms of polystyrene using the above-mentioned gel permeation chromatography (HPLC GPC system manufactured by Shimadzu Corporation).
  • the glass transition temperature (Tg) of the resin was determined by differential scanning calorimetry in accordance with JIS K-7121. Specifically, first, about 5 mg of the sample to be measured was precisely weighed, and the temperature was raised from -20°C to 200°C at a heating rate of 10°C/min using a differential scanning calorimeter (SSC5200, manufactured by Seiko Instruments Inc.) to obtain a DSC curve.
  • SSC5200 differential scanning calorimeter
  • the glass transition temperature (Tg) in a portion where the baseline changes stepwise due to the glass transition, the baselines before and after the change were extended, and a center line was drawn equidistant in the vertical direction from these two straight lines, and the temperature at the point where this center line intersects with the curve of the stepwise change due to the glass transition was determined as the glass transition temperature (Tg).
  • the melting point was determined by differential scanning calorimetry in accordance with JIS K-7121. Specifically, first, about 4 to 5 mg of the sample to be measured was precisely weighed, and the temperature was raised from 0° C. to 180° C. at a heating rate of 10° C./min using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., SSC5200) to obtain a DSC curve. In the obtained DSC curve, the apex temperature of the melting point peak was taken as the melting point.
  • the thickness was measured at 10 points at 10 cm intervals along the TD direction of the film using a vernier caliper, and the arithmetic mean value of the thicknesses at the 10 points was calculated to be the film thickness.
  • Example 1 The cylinder temperature and die temperature of a ⁇ 40 mm single-screw extruder connected to a T-die with a width of 350 mm were each set to 165 ° C.
  • the dry blend was put into the single-screw extruder and melted, and the molten resin at a temperature of 165 ° C. was extruded into a film shape with a T-die.
  • the film-shaped molten resin was extruded onto a cast roll set at 40 ° C. and molded at a take-up speed of 2 m / min, and cooled to a film temperature of 30 ° C., and the film was peeled off from the cast roll to obtain a film with a thickness of about 300 ⁇ m.
  • the film peeled off from the casting roll was taken up by a take-up roll and continuously stretched in the roll longitudinal stretching machine to a stretch ratio of 2.9 times in the MD direction at a film temperature of 60°C during stretching.
  • the film temperature at this time was controlled by adjusting the roll temperature in the roll longitudinal stretching machine to the same temperature (60°C).
  • the film was continuously stretched in the clip-type tenter transverse stretching machine to a stretch ratio of 4.5 times in the TD direction at a film temperature of 70°C during stretching.
  • the film temperature at this time was controlled by applying hot air (airflow) of the same temperature (70°C) to the film inside the transverse stretching machine.
  • the film was heat-treated in a clip-type tenter transverse stretching machine with a film temperature of 130°C, a heating time of 10 seconds, and a relaxation amount in the TD direction of 10%, with 130°C hot air being applied to the film, to obtain a biaxially stretched film with a thickness of 25 ⁇ m.
  • the amount of heat shrinkage of the obtained film at 110°C was measured, and it was found to be an excellent film with a small amount of heat shrinkage of less than 10%, with 2% in the MD direction and 7% in the TD direction. The results are shown in Table 1.
  • the heat treatment temperature or the relaxation amount during heat treatment was low, so the heat treatment effect was not sufficient, and the heat shrinkage amount in the TD direction was 10% or more.
  • the relaxation amount during heat treatment was set to a large amount of 60%, so slack occurred in the film after heat treatment. If slack occurs in the film, the film may come into contact with the manufacturing equipment, including the heating equipment, and the film may break.
  • Example 6 The cylinder temperature and die temperature of a ⁇ 40 mm single-screw extruder connected to a T-die with a width of 350 mm were set to 165 ° C., respectively.
  • the dry blend was put into the single-screw extruder, melted, and the molten resin at a temperature of 165 ° C. was extruded into a film shape with a T-die.
  • the film-shaped molten resin was extruded onto a cast roll set at 40 ° C. and molded at a take-up speed of 2 m / min, and cooled to a film temperature of 40 ° C., and the film was peeled off from the cast roll to obtain a film with a thickness of about 300 ⁇ m.
  • the film peeled off from the casting roll was taken up by a take-up roll and continuously stretched in a roll longitudinal stretching machine to a stretch ratio of 3 in the MD direction at a film temperature of 60°C during stretching.
  • the film temperature at this time was controlled by adjusting the roll temperature in the roll longitudinal stretching machine to the same temperature (60°C).
  • the obtained MD stretched film was cut into MD 90 mm x TD 350 mm and stretched in the TD direction to a stretch ratio of 5 in a uniaxial stretching machine at a film temperature of 70°C during stretching.
  • the film temperature at this time was controlled by applying hot air (airflow) of the same temperature (70°C) to the film inside the stretching machine.
  • a preliminary heat treatment was performed in the uniaxial stretching machine by applying 120°C hot air to the film at a film temperature of 120°C, a heating time of 30 seconds, and a relaxation amount in the TD direction of 0%.
  • the film was heat-treated in a uniaxial stretching machine with a film temperature of 120°C, a heating time of 30 seconds, and a relaxation amount in the TD direction of 20%, with 120°C hot air being applied to the film, to obtain a biaxially stretched film with a thickness of 25 ⁇ m.
  • the amount of heat shrinkage of the obtained film at 110°C was measured, and it was found to be an excellent film with a small amount of heat shrinkage of less than 10%, with 2% in the MD direction and 4% in the TD direction. The results are shown in Table 2.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Organic Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Medicinal Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electromagnetism (AREA)
  • Toxicology (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Materials Engineering (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
PCT/JP2024/010810 2023-03-24 2024-03-19 延伸フィルムの製造方法 Ceased WO2024203640A1 (ja)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2025510592A JPWO2024203640A1 (https=) 2023-03-24 2024-03-19
US19/339,028 US20260021641A1 (en) 2023-03-24 2025-09-24 Method for producing stretched film

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2023047825 2023-03-24
JP2023-047825 2023-03-24
JP2023-154111 2023-09-21
JP2023154111 2023-09-21

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US19/339,028 Continuation US20260021641A1 (en) 2023-03-24 2025-09-24 Method for producing stretched film

Publications (1)

Publication Number Publication Date
WO2024203640A1 true WO2024203640A1 (ja) 2024-10-03

Family

ID=92904905

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2024/010810 Ceased WO2024203640A1 (ja) 2023-03-24 2024-03-19 延伸フィルムの製造方法

Country Status (3)

Country Link
US (1) US20260021641A1 (https=)
JP (1) JPWO2024203640A1 (https=)
WO (1) WO2024203640A1 (https=)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN119592033A (zh) * 2024-12-23 2025-03-11 江苏集萃先进高分子材料研究所有限公司 一种聚乳酸取向薄膜及其制备方法
WO2025182626A1 (ja) * 2024-02-26 2025-09-04 株式会社カネカ 延伸フィルムの製造方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05508819A (ja) * 1990-07-16 1993-12-09 イー・アイ・デュポン・ドウ・ヌムール・アンド・カンパニー ポリヒドロキシ酸フィルム
JPH09132701A (ja) * 1995-11-07 1997-05-20 Gunze Ltd 微生物分解性フィルム
JPH09314658A (ja) * 1996-05-31 1997-12-09 Kohjin Co Ltd 一軸延伸脂肪族ポリエステルフィルム及びその製造方法
JP2003311825A (ja) * 2002-04-25 2003-11-06 Inst Of Physical & Chemical Res ポリヒドロキシアルカン酸からなる高強度フィルムおよびその製造法
JP2022062759A (ja) * 2020-10-09 2022-04-21 株式会社カネカ 二軸延伸フィルムの製造方法
WO2022173465A1 (en) * 2021-02-09 2022-08-18 Newlight Technologies, Inc. Composition and method for production of a highly flexible pha sheet

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05508819A (ja) * 1990-07-16 1993-12-09 イー・アイ・デュポン・ドウ・ヌムール・アンド・カンパニー ポリヒドロキシ酸フィルム
JPH09132701A (ja) * 1995-11-07 1997-05-20 Gunze Ltd 微生物分解性フィルム
JPH09314658A (ja) * 1996-05-31 1997-12-09 Kohjin Co Ltd 一軸延伸脂肪族ポリエステルフィルム及びその製造方法
JP2003311825A (ja) * 2002-04-25 2003-11-06 Inst Of Physical & Chemical Res ポリヒドロキシアルカン酸からなる高強度フィルムおよびその製造法
JP2022062759A (ja) * 2020-10-09 2022-04-21 株式会社カネカ 二軸延伸フィルムの製造方法
WO2022173465A1 (en) * 2021-02-09 2022-08-18 Newlight Technologies, Inc. Composition and method for production of a highly flexible pha sheet

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2025182626A1 (ja) * 2024-02-26 2025-09-04 株式会社カネカ 延伸フィルムの製造方法
CN119592033A (zh) * 2024-12-23 2025-03-11 江苏集萃先进高分子材料研究所有限公司 一种聚乳酸取向薄膜及其制备方法

Also Published As

Publication number Publication date
JPWO2024203640A1 (https=) 2024-10-03
US20260021641A1 (en) 2026-01-22

Similar Documents

Publication Publication Date Title
JP2025116158A (ja) 二軸延伸フィルムの製造方法
JP7807897B2 (ja) 延伸フィルムの製造方法
US20260021641A1 (en) Method for producing stretched film
CN100379800C (zh) 可生物降解的树脂膜或片及其制造方法
US20260022219A1 (en) Method for producing stretched film
JP2023146094A (ja) 熱可塑性樹脂フィルムの製造方法
EP4410893A1 (en) Blow-molded article and method for producing same
US20260109105A1 (en) Method for producing stretched film
WO2023090176A1 (ja) 延伸フィルム及びその製造方法
JP7477982B2 (ja) 樹脂フィルム、その製造方法、及び成形体
WO2023090175A1 (ja) 延伸フィルムの製造方法
CN119116514A (zh) 一种多层结构的生物降解气调膜
WO2025182626A1 (ja) 延伸フィルムの製造方法
EP4636035A1 (en) Resin composition for forming stretched film
WO2025013664A1 (ja) 押出フィルム
JP2025001853A (ja) 延伸フィルム
CN118922291A (zh) 拉伸膜的制造方法
JP3623053B2 (ja) 生分解性樹脂成形体
WO2024262377A1 (ja) フィルム
JP7477981B2 (ja) 樹脂フィルム、その製造方法、及び成形体
EP4624127A1 (en) Method for producing pellets comprising polyhydroxyalkanoate, and pellets produced thereby
WO2025070023A1 (ja) 熱可塑性樹脂フィルムの製造方法
JP7564652B2 (ja) 成形体の製造方法
WO2024262378A1 (ja) 延伸フィルム
WO2025187804A1 (ja) 多層延伸フィルム及び多層延伸フィルムの製造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24779765

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2025510592

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2025510592

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 24779765

Country of ref document: EP

Kind code of ref document: A1