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
  • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
  • B29C43/003—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor characterised by the choice of material
• • 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
  • 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
• • 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
  • B29K2067/04—Polyesters derived from hydroxycarboxylic acids
• • 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

Definitions

• the present invention relates to a poly(3-hydroxyalkanoate)-based resin composition for molding and its molded article.
• biodegradable plastics from the viewpoint of biodegradability and carbon neutrality, biodegradable plastics produced by microorganisms using plant-derived raw materials as a carbon source, particularly aliphatic polyester-based resins, have been attracting attention.
• poly(3-hydroxyalkanoate)-based resins such as poly(3-hydroxybutyrate) homopolymer resin, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer resin, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin, and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer resin have been attracting attention.
• the poly(3-hydroxyalkanoate) resins and particularly the poly(3-hydroxyalkanoate) copolymers, have a problem in that they have a slow crystallization rate, resulting in low productivity during melt molding.
• Patent Document 1 discloses an aliphatic polyester resin composition that improves the crystallization rate by containing a low molecular weight aliphatic polyester, a high molecular weight aliphatic polyester, and a specific crystallization promoter such as an amide group-containing compound.
• the weight-average molecular weight of the low-molecular-weight polyester is as low as 30,000 or less, making it difficult to stably carry out the molding process under practical processing conditions.
• Patent Document 2 discloses a resin composition containing two types of poly(3-hydroxyalkanoate) resins having melting temperatures differing by 5° C. or more, for the purpose of providing a film having gas barrier properties against oxygen, water vapor, and the like, and flexibility.
• the crystallization promoting effect there is no description of the crystallization promoting effect, and the formulation disclosed in the document does not provide sufficient productivity, and improvements were necessary.
• the present invention aims to provide a poly(3-hydroxyalkanoate)-based resin composition for molding that exhibits an improved crystallization rate after application of shear, and a molded article made from the composition.
• the inventors used an apparatus capable of measuring crystallization after heating and melting a resin and applying shear to evaluate the crystallization rate and crystal morphology, and focused on finding a resin composition that can achieve a significant crystallization promotion effect under those conditions.
• the inventors of the present invention have conducted extensive research to solve the above problems, and have discovered that by mixing a poly(3-hydroxyalkanoate) copolymer (A) having a weight-average molecular weight of 100,000 to 1,000,000, a poly(3-hydroxyalkanoate) copolymer (B) having a weight-average molecular weight of 300,000 to 3,000,000 and greater than that of copolymer (A), and a poly(3-hydroxybutyrate) resin to form a resin composition for molding, crystallization after application of shear is promoted even when the poly(3-hydroxybutyrate) resin is heated to 185°C or higher at which it completely melts, and thus completing the present invention.
• the present invention provides a poly(3-hydroxyalkanoate) copolymer (A) having a weight average molecular weight (herein after, the weight average molecular weight refers to a weight average molecular weight calculated in terms of polystyrene as determined by gel permeation chromatography using a chloroform solvent) of 100,000 or more and 1,000,000 or less; A poly(3-hydroxyalkanoate) copolymer (B) having a weight average molecular weight of 300,000 or more and 3,000,000 or less; and Contains poly(3-hydroxybutyrate) resin (C),
• the present invention relates to a poly(3-hydroxyalkanoate)-based resin composition for molding, in which the weight average molecular weight of the poly(3-hydroxyalkanoate)-based copolymer (B) is greater than the weight average molecular weight of the poly(3-hydroxyalkanoate)-based copolymer (A).
• the present invention also relates to a molded article comprising the poly
• a poly(3-hydroxyalkanoate)-based resin composition for molding which has an improved crystallization rate after application of shear, and a molded article made from the composition.
• the crystallization rate after application of shear is improved, and therefore melt molding using the resin composition can be carried out stably with good productivity under practical processing conditions.
• the range of temperature conditions that can be selected during molding including the process of melting and cooling and solidifying a molding material containing a poly(3-hydroxyalkanoate) resin, is wide, making it possible to produce a molded article having a relatively uniform thickness and weight and a good appearance, and also improving productivity, making it possible to mass-produce molded articles at high speed.
• FIG. 1 is a diagram illustrating an example of a polarizing microscope photograph showing the morphology of crystals observed in the examples or comparative examples, and an evaluation method thereof.
• the resin composition according to the present embodiment is a resin composition mainly composed of a poly(3-hydroxyalkanoate) copolymer, and is used to form a molded product by heating and melting the resin composition and then cooling and solidifying the same. In particular, applying shear during heating and melting the resin composition promotes crystallization, thereby improving the productivity of the molded product.
• the resin composition according to this embodiment is a poly(3-hydroxyalkanoate)-based resin composition that contains at least a poly(3-hydroxyalkanoate)-based copolymer (A) having a weight-average molecular weight of 100,000 or more and 1,000,000 or less, a poly(3-hydroxyalkanoate)-based copolymer (B) having a weight-average molecular weight of 300,000 or more and 3,000,000 or less, and a poly(3-hydroxybutyrate) resin (C).
• A poly(3-hydroxyalkanoate)-based copolymer having a weight-average molecular weight of 100,000 or more and 1,000,000 or less
• B poly(3-hydroxyalkanoate)-based copolymer having a weight-average molecular weight of 300,000 or more and 3,000,000 or less
• C poly(3-hydroxybutyrate) resin
• the poly(3-hydroxyalkanoate) copolymers (A) and (B) are biodegradable aliphatic polyesters (preferably polyesters not containing aromatic rings) and are copolymers having at least one or more types of 3-hydroxyalkanoate units.
• the poly(3-hydroxyalkanoate) copolymer is also referred to as P3HA.
• the 3-hydroxyalkanoate unit is preferably represented by the following general formula (1). [-CHR-CH 2 -CO-O-] (1)
• R represents an alkyl group represented by C p H 2p+1 , and p represents an integer of 1 to 15.
• R include linear or branched alkyl groups such as methyl, ethyl, propyl, methylpropyl, butyl, isobutyl, t-butyl, pentyl, and hexyl.
• p is preferably 1 to 10, and more preferably 1 to 8.
• poly(3-hydroxyalkanoate) copolymer (A) and/or (B) a poly(3-hydroxyalkanoate) copolymer produced from a microorganism is particularly preferred.
• a poly(3-hydroxyalkanoate) copolymer produced from a microorganism all of the 3-hydroxyalkanoate units are contained as (R)-3-hydroxyalkanoate units.
• the poly(3-hydroxyalkanoate) copolymer (A) and/or (B) preferably contains 3-hydroxyalkanoate units (particularly units represented by general formula (1)) in an amount of 50 mol% or more of the total constituent units (monomer units), more preferably 60 mol% or more, and even more preferably 70 mol% or more.
• the poly(3-hydroxyalkanoate) copolymer may contain only two or more types of 3-hydroxyalkanoate units as the constituent units of the polymer, or may contain other units (e.g., 4-hydroxyalkanoate units, etc.) in addition to one or more types of 3-hydroxyalkanoate units.
• the poly(3-hydroxyalkanoate) copolymer (A) and/or (B) is preferably a copolymer containing 3-hydroxybutyrate (hereinafter sometimes referred to as 3HB) units and other hydroxyalkanoate units. It is preferable that the 3-hydroxybutyrate units are all (R)-3-hydroxybutyrate units.
• the other hydroxyalkanoate units may be 3-hydroxyalkanoate units other than 3HB units, or may be hydroxyalkanoate units other than 3-hydroxyalkanoate units (e.g., 4-hydroxyalkanoate units).
• the other hydroxyalkanoate units may include only one type, or may include two or more types.
• poly(3-hydroxyalkanoate) copolymers (A) and/or (B) include, for example, poly(3-hydroxybutyrate-co-3-hydroxypropionate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (abbreviation: P3HB3HV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (abbreviation: P3HB3HH), Examples include poly(3-hydroxybutyrate-co-3-hydroxyheptanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxynonanoate), poly(3-hydroxybutyrate-co-3-hydroxydecanoate), poly(3-hydroxybutyrate-co-3-hydroxyundecanoate), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (abbreviation:
• P3HA can be produced by microorganisms. Such microbially produced P3HA is usually P3HA composed only of D-form (R-form) hydroxyalkanoic acid repeating units. Among microbially produced P3HA, P3HB3HH, P3HB3HV, P3HB3HV3HH, and P3HB4HB are preferred, P3HB3HH, P3HB3HV, and P3HB4HB are more preferred, and P3HB3HH is particularly preferred, in terms of ease of industrial production. P3HA (A) and P3HA (B) may be copolymers having the same monomer species, or may be copolymers having different monomer species.
• the microorganisms that produce P3HA are not particularly limited as long as they have the ability to produce P3HA.
• the first P3HB-producing bacterium was Bacillus megaterium, discovered in 1925, and other natural microorganisms are known, including Cupriavidus necator (formerly classified as Alcaligenes eutrophus, Ralstonia eutropha) and Alcaligenes latus. In these microorganisms, P3HB accumulates within the bacterial cells.
• Microbial cells in which such microorganisms are cultured under appropriate conditions and P3HA has accumulated within the cells are used.
• genetically modified microorganisms into which various P3HA synthesis-related genes have been introduced may be used according to the P3HA to be produced, and culture conditions, including the type of substrate, may be optimized.
• the weight-average molecular weight of the poly(3-hydroxyalkanoate) copolymer (A) is in the range of 100,000 to 1,000,000.
• the weight-average molecular weight of P3HA (A) 100,000 or more a molded product exhibiting good physical properties can be formed by melting and then cooling it. Furthermore, by using it in combination with P3HA (B) and poly(3-hydroxybutyrate) resin (C) described later, crystallization after melting the resin composition and applying shear is promoted, and molded products can be produced with good productivity.
• the weight-average molecular weight of P3HA (A) 1,000,000 or less processability is further improved and molding becomes easier.
• the weight-average molecular weight of P3HA (A) is preferably 200,000 to 800,000. It may also be 230,000 or more. Furthermore, 250,000 to 700,000 is more preferable, and 300,000 to 600,000 is even more preferable.
• the weight-average molecular weight of P3HA can be determined as the molecular weight converted into polystyrene using gel permeation chromatography (GPC) (Shimadzu Corporation's "High Performance Liquid Chromatograph 20A System"), a polystyrene gel (Showa Denko KK's "K-G 4A” and “K-806M”) as the column, and chloroform as the mobile phase.
• GPC gel permeation chromatography
• a polystyrene gel Showa Denko KK's "K-G 4A” and "K-806M”
• chloroform as the mobile phase.
• a calibration curve is created using polystyrene with weight-average molecular weights of 31,400, 197,000, 668,000, and 1,920,000.
• the column used in the GPC should be a column appropriate for measuring the molecular weight.
• the poly(3-hydroxyalkanoate) copolymer (A) is a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, and the content of the other hydroxyalkanoate units is preferably 1 mol% or more and 23 mol% or less.
• the content is more preferably 1 to 20 mol%, even more preferably 1 to 15 mol%, and particularly preferably 1 to 10 mol%.
• the lower limit of the content may be 2 mol% or more, or 3 mol% or more.
• the monomer composition ratio in P3HA can be measured by gas chromatography or the like, see, for example, the description in International Publication No. 2014/020838.
• the weight average molecular weight of the poly(3-hydroxyalkanoate) copolymer (B) is in the range of 300,000 to 3,000,000, and is greater than the weight average molecular weight of the P3HA (A) described above.
• P3HA (B) with a weight average molecular weight of 300,000 or more and greater than that of P3HA (A), the molecular chains of this high molecular weight component are easily oriented under melt shear, which induces crystallization, and by melting and applying shear, crystallization is promoted, allowing molded products to be produced with good productivity.
• the weight average molecular weight of P3HA (B) is preferably 400,000 to 2,000,000, more preferably 500,000 to 1,000,000, and even more preferably 600,000 to 900,000.
• the weight average molecular weight of P3HA(B) is preferably 100,000 or more larger than the weight average molecular weight of P3HA(A), more preferably 150,000 or more larger, even more preferably 200,000 or more larger, and particularly preferably 250,000 or more larger.
• weight average molecular weight between P3HA(B) and P3HA(A) is preferably 2,000,000 or less, more preferably 1,000,000 or less, even more preferably 800,000 or less, and particularly preferably 600,000 or less.
• the poly(3-hydroxyalkanoate) copolymer (B) is a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, and the content of the other hydroxyalkanoate units is preferably 1 mol% or more and 23 mol% or less.
• the content is more preferably 1 to 20 mol%, even more preferably 1 to 15 mol%, and particularly preferably 1 to 10 mol%.
• the lower limit of the content may be 2 mol% or more, or may be 3 mol% or more.
• the content ratio of P3HA(A) and P3HA(B) may be set appropriately. However, since the crystallization-promoting effect is more easily achieved by using P3HA(B), which is a high molecular weight component, it is preferable that the ratio of P3HA(A) is 50% by weight or more and 99.9% by weight or less, and the ratio of P3HA(B) is 0.1% by weight or more and 50% by weight or less, relative to the total of both components (100% by weight).
• the ratio of P3HA(A) is 60 to 99% by weight
• the ratio of P3HA(B) is 1 to 40% by weight
• the ratio of P3HA(A) is 70 to 97% by weight
• the ratio of P3HA(B) is 3 to 30% by weight.
• the ratio of P3HA(A) may be 80% by weight or more and the ratio of P3HA(B) may be 20% by weight or less, or the ratio of P3HA(A) may be 90% by weight or more and the ratio of P3HA(B) may be 10% by weight or less.
• the poly(3-hydroxyalkanoate)-based resin composition for molding according to this embodiment further contains a poly(3-hydroxybutyrate) resin (C).
• This resin (C) is more easily crystallized than a poly(3-hydroxyalkanoate)-based copolymer, and in addition, the molecular chains of the resin (C) are more easily oriented under melt shear, thereby inducing crystallization. Therefore, even if the resin (C) is heated to 185° C. or higher at which it completely melts, the crystallization of the resin composition can be promoted by applying shear.
• this resin (C) in combination with the above-mentioned P3HA (B), crystallization after the application of shear is synergistically promoted, and molded articles can be produced with good productivity.
• Poly(3-hydroxybutyrate) resin (C) refers to a homopolymer of 3-hydroxybutyrate, or a polymer that contains a small amount of hydroxyalkanoate units other than 3-hydroxybutyrate units in addition to 3-hydroxybutyrate units. Specifically, it is preferable that poly(3-hydroxybutyrate) resin (C) contains 3-hydroxybutyrate units in a proportion of more than 99 mol% and not more than 100 mol% of the total constituent monomers.
• Hydroxyalkanoate units other than 3-hydroxybutyrate units that may be contained in poly(3-hydroxybutyrate) resin (C) are not particularly limited as long as they are copolymerizable with 3-hydroxybutyrate units, but examples include 3-hydroxyalkanoate units other than 3-hydroxybutyrate units and hydroxyalkanoate units other than 3-hydroxyalkanoate units (e.g., 4-hydroxyalkanoate units). In particular, 3-hydroxyhexanoate units are preferred.
• the weight average molecular weight of poly(3-hydroxybutyrate) resin (C) may be set as appropriate, but is preferably within the range of 10,000 to 1,000,000.
• the weight average molecular weight of resin (C) is 10,000 or more, the crystallization promoting effect of using resin (C) tends to be more easily manifested. It is more preferably 100,000 or more, even more preferably 200,000 or more, and particularly preferably 250,000 or more.
• the weight average molecular weight of resin (C) is 1,000,000 or less, there is a tendency that lumps are less likely to occur in the molded product, processability is improved, and molding is easier. It is more preferably 800,000 or less, even more preferably 500,000 or less, and particularly preferably 400,000 or less.
• the amount of poly(3-hydroxybutyrate) resin (C) may be set as appropriate. However, because the use of resin (C) is more likely to promote crystallization and the biodegradability of the resin composition may be improved, it is preferably 0.1 to 50 parts by weight per 100 parts by weight of P3HA (A) and P3HA (B) combined. 0.5 to 40 parts by weight is more preferable, 1 to 30 parts by weight is even more preferable, and 3 to 20 parts by weight is particularly preferable. The upper limit of the amount of resin (C) may be 15 parts by weight or less, or 10 parts by weight or less.
• the poly(3-hydroxyalkanoate)-based resin composition for molding according to this embodiment is different from the expanded resin particles disclosed in WO 2019/146555 or WO 2022/054870, and is preferably a non-expanded resin composition that does not substantially contain air bubbles inside.
• the poly(3-hydroxyalkanoate)-based resin composition for molding according to this embodiment is not foamed, it has a relatively large density, preferably exceeding 0.3 g/ cm3 , more preferably 0.5 g/ cm3 or more, and even more preferably 0.7 g/ cm3 or more. There is no particular upper limit, but it may be, for example, 1.6 g/ cm3 or less, or 1.4 g/ cm3 or less.
• the density of the resin composition can be determined by the method described in JIS K0061 (Method for measuring density and specific gravity of chemical products) or JIS Z8807 (Method for measuring density and specific gravity of solids).
• the poly(3-hydroxyalkanoate)-based resin composition for molding according to this embodiment may contain, in addition to P3HA (A), P3HA (B), and poly(3-hydroxybutyrate) resin (C), optionally at least one selected from the group consisting of other resins, crystal nucleating agents, and lubricants.
• the poly(3-hydroxyalkanoate)-based resin composition for molding may contain another resin that does not fall under any of P3HA (A), P3HA (B), and poly(3-hydroxybutyrate) resin (C).
• the other resin does not significantly reduce the compatibility or moldability when molding the poly(3-hydroxyalkanoate)-based resin composition for molding, or the mechanical properties of the resulting molded article.
• the other resin is preferably a biodegradable resin.
• the other resins include, for example, aliphatic polyesters having a structure in which aliphatic diols and aliphatic dicarboxylic acids are polycondensed, and aliphatic aromatic polyesters having both aliphatic and aromatic compounds as monomers.
• the former include polyethylene succinate, polybutylene succinate (PBS), polyhexamethylene succinate, polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polybutylene succinate adipate (PBSA), polyethylene sebacate, polybutylene sebacate, etc.
• Examples of the latter include poly(butylene adipate-co-butylene terephthalate) (PBAT), poly(butylene sebacate-co-butylene terephthalate), poly(butylene azelate-co-butylene terephthalate), poly(butylene succinate-co-butylene terephthalate) (PBST), etc.
• PBAT poly(butylene adipate-co-butylene terephthalate)
• PBST poly(butylene sebacate-co-butylene terephthalate)
• PBST poly(butylene succinate-co-butylene terephthalate)
• the other resins may be used alone or in combination of two or more.
• the content of the other resin is preferably 250 parts by weight or less, more preferably 100 parts by weight or less, even more preferably 50 parts by weight or less, and particularly preferably 20 parts by weight or less, per 100 parts by weight of the total of P3HA (A), P3HA (B), and poly(3-hydroxybutyrate) resin (C). It may also be 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less. There is no particular lower limit for the content of the other resin, and it may be 0 parts by weight.
• the poly(3-hydroxyalkanoate)-based resin composition for molding may further contain a crystal nucleating agent.
• a crystal nucleating agent By containing a crystal nucleating agent in the poly(3-hydroxyalkanoate)-based resin composition for molding, crystallization of the resin component is further promoted, and molding speed, productivity, etc. can be improved.
• the crystal nucleating agent is not particularly limited, and any conventionally known agent can be used, for example, inorganic substances such as pentaerythritol, boron nitride, titanium oxide, talc, layered silicates, calcium carbonate, sodium chloride, and metal phosphates; sugar alcohol compounds derived from natural products such as erythritol, galactitol, mannitol, and arabitol; polyvinyl alcohol, chitin, chitosan, polyethylene oxide, aliphatic carboxylic acid amides, aliphatic carboxylic acid salts, aliphatic alcohols, aliphatic carboxylic acid esters, and dimethyl adipate.
• inorganic substances such as pentaerythritol, boron nitride, titanium oxide, talc, layered silicates, calcium carbonate, sodium chloride, and metal phosphates
• sugar alcohol compounds derived from natural products such as erythri
• dicarboxylic acid derivatives such as dibutyl adipate, diisodecyl adipate, dibutyl sebacate, etc.
• cyclic compounds having a functional group C O and a functional group selected from NH, S, and O in the molecule, such as indigo, quinacridone, and quinacridone magenta
• sorbitol derivatives such as bisbenzylidene sorbitol and bis(p-methylbenzylidene) sorbitol
• compounds containing a nitrogen-containing heteroaromatic nucleus such as pyridine, triazine, and imidazole
• phosphate ester compounds bisamides of higher fatty acids, and metal salts of higher fatty acids.
• the content of the crystal nucleating agent is not particularly limited as long as it can promote the crystallization of the resin components, but is preferably 0.05 to 12 parts by weight, more preferably 0.1 to 10 parts by weight, and even more preferably 0.5 to 8 parts by weight, per 100 parts by weight of the total of P3HA (A), P3HA (B), and poly(3-hydroxybutyrate) resin (C).
• the content of the crystal nucleating agent is within the above range, it is possible to obtain the effect of the crystal nucleating agent while suppressing the decrease in viscosity during molding and the physical properties of the molded body.
• the poly(3-hydroxyalkanoate)-based resin composition for molding may be substantially free of sugar alcohols such as pentaerythritol.
• Substantially free of sugar alcohols means that the amount of sugar alcohols is less than 0.05 parts by weight per 100 parts by weight of the total of P3HA (A), P3HA (B), and poly(3-hydroxybutyrate) resin (C). It may be less than 0.01 parts by weight.
• sugar alcohols are substantially free of sugar alcohols, it is possible to avoid the problems of bleeding out of sugar alcohols from the resin composition and the associated contamination of the manufacturing equipment. According to this embodiment, good productivity can be achieved even without substantially adding sugar alcohols, which are crystal nucleating agents.
• the poly(3-hydroxyalkanoate)-based resin composition for molding may further contain a lubricant.
• a lubricant By containing a lubricant, the surface smoothness of the obtained molded article can be improved.
• the lubricant is not particularly limited, but it is preferable that the composition contains at least one selected from the group consisting of behenic acid amide, stearic acid amide, erucic acid amide, and oleic acid amide.
• the obtained molded article can have good lubricity (particularly external lubricity).
• the lubricant may be behenamide, stearamide, erucamide, oleamide or a combination of two or more of these, or it may be a combination of behenamide, stearamide, erucamide or oleamide with a lubricant other than these (hereinafter referred to as "other lubricants").
• Examples of other lubricants include, but are not limited to, alkylene fatty acid amides such as methylene bisstearic acid amide and ethylene bisstearic acid amide; polyethylene wax, oxidized polyester wax, glycerin monostearate, glycerin monobehenate, glycerin monolaurate, and other glycerin monofatty acid esters; organic acid monoglycerides such as succinic acid saturated fatty acid monoglycerides; sorbitan fatty acid esters such as sorbitan behenate, sorbitan stearate, and sorbitan laurate; polyglycerin fatty acid esters such as diglycerin stearate, diglycerin laurate, tetraglycerin stearate, tetraglycerin laurate, decaglycerin stearate, and decaglycerin laurate; and higher alcohol fatty acid esters such as stearyl stearate.
• the amount of the lubricant (the total amount when multiple lubricants are used) is not particularly limited as long as it can impart lubricity to the molded body, but is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, more preferably 0.5 to 10 parts by weight, even more preferably 0.5 to 5 parts by weight, and particularly preferably 0.7 to 4 parts by weight, per 100 parts by weight of the total of P3HA (A), P3HA (B), and poly(3-hydroxybutyrate) resin (C).
• the amount of the lubricant is within the above range, it is possible to obtain the effect of the lubricant while avoiding bleeding out of the lubricant onto the surface of the molded body.
• the poly(3-hydroxyalkanoate)-based resin composition for molding may contain other components, such as plasticizers, inorganic fillers, antioxidants, ultraviolet absorbers, colorants such as dyes and pigments, and antistatic agents, within the range that does not impair the functions of the resulting molded article.
• the plasticizer is not particularly limited, but examples thereof include modified glycerin compounds such as glycerin diacetomonolaurate, glycerin diacetomonocaprylate, and glycerin diacetomonodecanoate; adipate compounds such as diethylhexyl adipate, dioctyl adipate, and diisononyl adipate; polyether ester compounds such as polyethylene glycol dibenzoate, polyethylene glycol dicaprylate, and polyethylene glycol diisostearate; benzoate compounds; epoxidized soybean oil; epoxidized fatty acid 2-ethylhexyl; and sebacic acid monoesters. These may be used alone or in combination of two or more. Among the above plasticizers, modified glycerin compounds and polyether ester compounds are preferred in terms of ease of availability and high effectiveness. These may be used alone or in combination of two or more.
• the inorganic filler is not particularly limited, but examples include clay, synthetic silicon, carbon black, barium sulfate, mica, glass fiber, whiskers, carbon fiber, calcium carbonate, magnesium carbonate, glass powder, metal powder, kaolin, graphite, molybdenum disulfide, zinc oxide, etc. These may be used alone or in combination of two or more.
• the antioxidant is not particularly limited, but examples thereof include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. These may be used alone or in combination of two or more.
• the ultraviolet absorbing agent is not particularly limited, but examples thereof include benzophenone compounds, benzotriazole compounds, triazine compounds, salicylic acid compounds, cyanoacrylate compounds, nickel complex compounds, etc. These may be used alone or in combination of two or more.
• the colorants such as pigments and dyes are not particularly limited, but examples include inorganic colorants such as titanium oxide, calcium carbonate, chromium oxide, cuprous oxide, calcium silicate, iron oxide, carbon black, graphite, titanium yellow, and cobalt blue; soluble azo pigments such as lake red, lithol red, and brilliant carmine; insoluble azo pigments such as dinitrile orange and fast yellow; phthalocyanine pigments such as monochlorophthalocyanine blue, polychlorophthalocyanine blue, and polybromophthalocyanine green; condensed polycyclic pigments such as indigo blue, perylene red, isoindolinone yellow, and quinacridone red; and dyes such as oracet yellow. These may be used alone or in combination of two or more.
• the antistatic agent is not particularly limited, but examples thereof include low molecular weight antistatic agents such as fatty acid ester compounds, aliphatic ethanolamine compounds, and aliphatic ethanolamide compounds, and polymeric antistatic agents. These may be used alone or in combination of two or more.
• the poly(3-hydroxyalkanoate)-based resin composition for molding can be produced by a known method. Specifically, the P3HA (A), P3HA (B), poly(3-hydroxybutyrate) resin (C), and other optional components are melt-kneaded using an extruder, kneader, Banbury mixer, kneading roll, or the like. When melt-kneading, it is preferable to mix while paying attention to the decrease in molecular weight due to thermal decomposition.
• the poly(3-hydroxyalkanoate)-based resin composition for molding can also be produced by dissolving each component in a soluble solvent and then removing the solvent.
• each component When produced by melt kneading, each component may be fed separately into an extruder, or each component may be mixed in advance and then fed into an extruder.
• melt kneading is performed using an extruder, the resulting poly(3-hydroxyalkanoate)-based resin composition for molding may be extruded into a strand shape and then cut to be processed into particle shapes such as bars, cylinders, elliptical cylinders, spheres, cubes, and rectangular prisms.
• the resin temperature during melt mixing cannot be generally determined because it depends on the melting point and melt viscosity of the resin used, but from the viewpoint of achieving good dispersibility while avoiding thermal decomposition of P3HA (A), P3HA (B), and poly(3-hydroxybutyrate) resin (C), it is preferably 140 to 200°C, more preferably 150 to 195°C, and even more preferably 160 to 190°C.
• a molded article can be produced from the poly(3-hydroxyalkanoate)-based resin composition for molding.
• the molding method is not particularly limited as long as it is a molding method including a process of heating and melting the resin composition, and then cooling and solidifying it. According to this embodiment, since the crystallization rate after melting the poly(3-hydroxyalkanoate)-based resin composition and applying shear is improved, it is preferable to carry out the heating and melting during molding under shear flow conditions. At this time, melt molding using the resin composition can be carried out stably under practical processing conditions with good productivity.
• the shear rate during molding cannot be generally defined because it depends on the molding method, the size of the molding machine, the melting point and melt viscosity of the resin used, etc., but from the viewpoint of promoting crystallization by application of shear while avoiding thermal decomposition of P3HA (A), P3HA (B), and poly(3-hydroxybutyrate) resin (C), it is preferably 10 sec -1 or more, more preferably 30 sec -1 or more, and even more preferably 50 sec -1 or more.
• the upper limit is not particularly limited, and may be 10,0000 sec -1 or less, or may be 500 sec -1 or less.
• the resin temperature during molding cannot be generally defined as it depends on the melting point and melt viscosity of the resin used, but from the viewpoint of achieving good dispersibility while avoiding thermal decomposition of P3HA (A), P3HA (B), and poly(3-hydroxybutyrate) resin (C), it is preferably 140 to 200°C, more preferably 150 to 195°C, and even more preferably 160 to 190°C.
• Poly(3-hydroxyalkanoate)-based resin compositions for molding, or molded articles made from said compositions can be suitably used in agriculture, fisheries, forestry, horticulture, medicine, hygiene products, the food industry, clothing, non-clothing, packaging, automobiles, building materials, and other fields.
• a poly(3-hydroxyalkanoate) copolymer (A) having a weight average molecular weight (herein after, the weight average molecular weight refers to a weight average molecular weight calculated in terms of polystyrene as determined by gel permeation chromatography using a chloroform solvent; the same applies hereinafter) of 100,000 to 1,000,000;
• [Item 2] 2. The poly(3-hydroxyalkanoate)-based resin composition for molding according to item 1, wherein the weight average molecular weight of the poly(3-hydroxyalkanoate)-based copolymer (B) is 150,000 or more larger than the weight average molecular weight of the poly(3-hydroxyalkanoate)-based copolymer (A).
• [Item 3] 3. The poly(3-hydroxyalkanoate)-based resin composition for molding according to item 1 or 2, wherein the weight average molecular weight of the poly(3-hydroxyalkanoate)-based copolymer (A) is 200,000 or more.
• the poly(3-hydroxyalkanoate)-based copolymer (A) and/or (B) is at least one selected from the group consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hydroxyhexan
• a weight ratio of the content of the poly(3-hydroxyalkanoate)-based copolymer (A) to the content of the poly(3-hydroxyalkanoate)-based copolymer (B) is 50/50 to 99.9/0.1.
• [Item 10] 10 A molded article comprising the poly(3-hydroxyalkanoate)-based resin composition for molding according to any one of items 1 to 9.
• Item 11 Item 11. The molded body according to item 10, wherein the molded body is melt molded under shear flow at a shear rate of 10 sec ⁇ 1 or more.
• P3HA(A) As P3HA(A), the following poly(3-hydroxybutyrate-co-3-hydroxyhexanoate): P3HB3HH (Kaneka Corporation, Kaneka biodegradable polymer GreenPlanet (registered trademark)) was used.
• P3HB3HH Kaneka Corporation, Kaneka biodegradable polymer GreenPlanet (registered trademark)
• the monomer composition ratio of P3HB3HH was determined as follows. 1 mL of sulfuric acid-methanol mixture (15:85) and 1 mL of chloroform were added to approximately 20 mg of P3HB3HH, the container was sealed, and heated at 100°C for 140 minutes to obtain the methyl ester of the P3HB3HH decomposition product. After cooling, 0.5 mL of deionized water was added and mixed well, and the mixture was left to stand until the aqueous and organic layers separated. The monomer unit composition of the P3HB3HH decomposition product in the separated organic layer was then analyzed by capillary gas chromatography. The ratio of 3-hydroxyhexanoate was calculated from the peak area obtained.
• the weight average molecular weight of P3HB3HH and P3HB was measured by first dissolving the resin to be measured in chloroform and heating in a hot water bath at 60° C. for 0.5 hours, filtering the soluble matter through a disposable PTFE filter having a pore size of 0.45 ⁇ m, and then using the filtrate to perform GPC measurement under the following conditions to determine the weight average molecular weight value.
• GPC measuring device Shimadzu Corporation high performance liquid chromatograph 20A system Column: Showa Denko K-G 4A (1 column), K-806M (2 columns) Sample concentration: 1 mg/ml Free solution: chloroform solution Free solution flow rate: 1.0 ml/min Sample injection volume: 100 ⁇ L Analysis time: 30 minutes Standard sample: Standard polystyrene
• the film was heated, sheared, and cooled under the following conditions using a polarizing microscope (DM2700P manufactured by Leica) equipped with a heat shear stage (CSS450 manufactured by Linkam) to which a parallel plate made of quartz was attached.
• the resin material that had reached 125 ° C. by cooling was observed every minute for 10 minutes with a camera installed in the eyepiece while maintaining the temperature, and the time when crystallization began, the morphology of the crystals, and the proportion of the crystals occupying the field of view (whether overall or partial) were evaluated.
• An example of a polarizing microscope photograph showing the morphology of the crystals observed under a polarizing microscope is shown in FIG.
• Heating temperature 185°C (after reaching 185°C, hold at 185°C for 2 minutes) Heating rate: 30°C/min. Timing of shear application: for 30 seconds starting 90 seconds after reaching 185°C, and during cooling from 185°C to 125°C. Shearing rate: 100sec -1 Cooling: from 185°C to 125°C Cooling rate: 10°C/min
• Example 1 A total of 100 parts by weight of 95% by weight of poly(3-hydroxyalkanoate)-based copolymer (A-1) and 5% by weight of poly(3-hydroxyalkanoate)-based copolymer (B-1) was dry-blended with 5 parts by weight of poly(3-hydroxybutyrate) resin (C-1), 0.5 parts by weight of behenamide (BA), and 0.5 parts by weight of erucamide (EA), and then the mixture was melt-kneaded and hot-pressed as described above, and the crystallization behavior was evaluated when a shear rate of 100 sec -1 was applied. The results are shown in Table 1.
• Example 2 and 3 Poly(3-hydroxyalkanoate)-based resin compositions for molding were prepared in the same manner as in Example 1, except that the type of poly(3-hydroxyalkanoate)-based copolymer (A) and the type of poly(3-hydroxyalkanoate)-based copolymer (B) were changed as shown in Table 1. The crystallization behavior was evaluated when a shear was applied at a shear rate of 100 sec -1 . The results are shown in Table 1.

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