Resin composition for t-die extrusion molding

Abstract

This resin composition for T-die extrusion molding comprises: 100 parts by weight of poly(3-hydroxyalkanoate) resin (A); 0.3 to 3 parts by weight of layered clay mineral (B) having an average particle diameter D50 of 1 to 5 μm and a specific surface area as determined by BET of 10-40 m2 / g; and 0.3 to 3 parts by weight of aliphatic acid amide compound (C). The resin composition demonstrates a melt viscosity of 300 to 1000 Pa.s as determined at 175°C and a shear velocity of 122 s-1.

Description

Resin composition for T-die extrusion molding

[0001] The present invention relates to a resin composition for T-die extrusion molding, a T-die extrusion molded film, a laminate, a molded article, a method for producing a film, and a method for producing a laminate.

[0002] In recent years, environmental problems caused by discarded plastics have been attracting attention. In particular, marine pollution caused by discarded plastics is serious, and there are high hopes for the widespread use of biodegradable plastics that decompose in the natural environment.

[0003] Various types of such biodegradable plastics are known, but poly(3-hydroxyalkanoate) resins (hereinafter sometimes referred to as P3HA resins) in particular are thermoplastic polyesters that are produced and accumulated as energy storage substances within the cells of many microbial species, and are materials that can biodegrade not only in soil but also in seawater, and therefore have attracted attention as a material that can solve the above-mentioned problems.

[0004] Furthermore, laminates produced by laminating a P3HA-based resin onto a biodegradable substrate such as paper are extremely promising from the perspective of environmental protection, since both the resin and the substrate are highly biodegradable materials. The lamination method can be selected from a method in which the P3HA-based resin is fed into an extruder equipped with a T-die, processed into a film, and then laminated onto a substrate, or an extrusion lamination method in which molten P3HA-based resin extruded from a T-die using similar equipment is directly laminated onto a separately unwound substrate without first being formed into a film.

[0005] Although Patent Document 1 does not relate to T-die extrusion molding, it describes a resin composition for injection molding containing 100 parts by weight of a poly(3-hydroxyalkanoate) resin having a specific monomer composition and 5 to 45 parts by weight of a layered clay mineral.

[0006] International Publication No. 2022 / 065182

[0007] Generally, P3HA-based resins have a slow crystallization rate, and therefore tend to stick to the cooling roll that contacts them immediately after the molten resin is extruded from a T-die. Therefore, a large force is applied when peeling the resin from the cooling roll, and fine irregularities are formed on the surface of the resin film or resin layer obtained by peeling, causing cloudy unevenness or wrinkles, which can deteriorate the appearance of the resin film or resin layer. However, it has been found that attempts to improve such peelability from the cooling roll increase a phenomenon called "neck-in," in which the width (length perpendicular to the flow direction) of the resin film or resin layer becomes smaller than the opening width of the T-die. In particular, when a P3HA-based resin with a relatively low molecular weight is used to improve peelability, the melt viscosity decreases, resulting in a significant increase in neck-in. Increased neck-in can sometimes prevent the target width from being achieved, or the edges become thicker, impairing thickness uniformity.

[0008] In view of the above, an object of the present invention is to provide a resin composition for T-die extrusion molding that contains a P3HA-based resin, which resin composition has improved releasability from a cooling roll after extrusion from a T-die and can reduce neck-in.

[0009] As a result of extensive research to solve the above problems, the present inventors have discovered that by blending specific amounts of a layered clay mineral having a specific structure and a fatty acid amide compound with a P3HA-based resin and controlling the melt viscosity of the resin composition under specific conditions to fall within a specific range, it is possible to improve the releasability from the cooling roll after extrusion from a T-die and reduce neck-in, thereby completing the present invention.

[0010] That is, the present invention provides a polymerizable composition comprising 100 parts by weight of a poly(3-hydroxyalkanoate) resin (A), an average particle diameter D50 determined by a laser diffraction method of 1 to 5 μm, and a specific surface area determined by a BET method of 10 to 40 m ２ / g of layered clay mineral (B) 0.3 to 3 parts by weight, and 0.3 to 3 parts by weight of fatty acid amide compound (C), －１The present invention relates to a resin composition for T-die extrusion molding, having a melt viscosity of 300 to 1000 Pa s as measured by a T-die extrusion lamination method. The present invention also relates to a T-die extrusion film containing the resin composition for T-die extrusion molding. The present invention also relates to a laminate containing a T-die extrusion resin layer containing the resin composition for T-die extrusion molding and a substrate layer. The present invention also relates to a molded article containing the laminate. The present invention also relates to a method for producing a film, comprising the step of melt-extrusion molding the resin composition for T-die extrusion molding using a T-die. The present invention also relates to a method for producing the laminate, comprising the step of forming the resin layer on at least one side of the substrate layer by extrusion lamination using a T-die. The present invention also relates to a method for producing the laminate, comprising: a step of melt-extrusion molding the resin composition for T-die extrusion molding using a T-die to form a film; and a step of placing the film on at least one surface of the base layer and forming the resin layer by any one of a dry lamination method, a non-solvent lamination method, and a thermal lamination method.

[0011] According to the present invention, it is possible to provide a resin composition for T-die extrusion molding containing a P3HA-based resin, which resin composition has improved releasability from a chill roll after extrusion from a T-die and can reduce neck-in. According to the present invention, a film or laminate containing a P3HA-based resin can be produced with good yield and high productivity using T-die extrusion. Furthermore, it becomes possible to carry out stable production over long periods of time. The obtained film or laminate has good surface condition due to its good releasability from a chill roll.

[0012] Hereinafter, an embodiment of the present invention will be described, but the present invention is not limited to the following embodiment. The resin composition according to this embodiment is a resin composition containing a poly(3-hydroxyalkanoate)-based resin (A) as an essential component.

[0013] [Poly(3-hydroxyalkanoate)-based resin (A)] Poly(3-hydroxyalkanoate)-based resin (A) (hereinafter also referred to as "P3HA-based resin (A)") is a biodegradable aliphatic polyester (a polyester containing no aromatic ring) and has the general formula: [-CHR-CH ２ 3-hydroxyalkanoic acid repeating units represented by the formula: —CO—O— (wherein R is C ｎ H ２ｎ＋１ where n is an integer of 1 to 15. Among these, polyhydroxyalkanoates containing the repeating unit are preferred, with the repeating unit accounting for 50 mol % or more, and more preferably 70 mol % or more, of the total monomer repeating units (100 mol %).

[0014] Among P3HA-based resins, poly(3-hydroxybutyrate)-based resins (hereinafter also referred to as "P3HB-based resins") are particularly preferred because they are easily available and easy to process.

[0015] The P3HB-based resin is an aliphatic polyester resin that can be produced from a microorganism and has 3-hydroxybutyrate (hereinafter, sometimes referred to as "3HB") as a repeating unit. The P3HB-based resin may be poly(3-hydroxybutyrate) having only 3HB as a repeating unit, or may be a copolymer of 3-hydroxybutyrate and another hydroxyalkanoate. The type of copolymerization is not particularly limited, and may be random copolymerization, alternating copolymerization, block copolymerization, graft copolymerization, or the like. Copolymers produced by microorganisms are usually random copolymers.

[0016] Specific examples of the P3HA-based resin (A) include poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (hereinafter, sometimes referred to as "P3HB3HH"), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (hereinafter, sometimes referred to as "P3HB3HV"), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate), poly(3-hydroxybutyrate-co-3-hydroxydecanoate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate), and the like. Among these, 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.

[0017] P3HB3HH is particularly preferred from the viewpoints that by changing the composition ratio of the repeating units, it is possible to change the melting point, the degree of crystallinity, and physical properties such as Young's modulus and heat resistance, and that it is possible to impart physical properties between those of polypropylene and polyethylene, and that it is a plastic that is easy to produce industrially and has useful physical properties.P3HB3HH is also preferred from the viewpoint that it can lower the melting point and enable molding processing at low temperatures.

[0018] Commercially available products of P3HB3HH include Kaneka Biodegradable Polymer Green Planet (registered trademark) manufactured by Kaneka Corporation.

[0019] The melting point, Young's modulus, etc. of P3HB3HV vary depending on the ratio of the 3-hydroxybutyrate component and the 3-hydroxyvalerate component. However, since both components co-crystallize, the degree of crystallinity is high at 50% or more, and although it is more flexible than poly(3-hydroxybutyrate), the improvement in brittleness is insufficient.

[0020] When the P3HA resin (A) contains a copolymer of 3-hydroxybutyrate and another hydroxyalkanoate, from the viewpoint of the balance between mechanical strength such as flexibility and solidification speed, the composition ratio of the monomer units in the copolymer (3-hydroxybutyrate units / other hydroxyalkanoate units) is preferably 90 / 10 to 99 / 1 (mol / mol), more preferably 92 / 8 to 98 / 2 (mol / mol), and even more preferably 94 / 6 to 97 / 3 (mol / mol).

[0021] Furthermore, the copolymer of 3-hydroxybutyrate and other hydroxyalkanoate, in which the 3-hydroxybutyrate unit / other hydroxyalkanoate unit ratio is 90 / 10 to 99 / 1 (mol / mol), preferably accounts for 50 to 100% by weight of the entire P3HA resin (A), more preferably 70 to 100% by weight, even more preferably 80 to 100% by weight, even more preferably 90 to 100% by weight, and particularly preferably 95 to 100% by weight.

[0022] The molar ratio of each monomer unit to all monomer units constituting the copolymer 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.

[0023] The weight average molecular weight (hereinafter sometimes referred to as "Mw") of the P3HA resin (A) is not particularly limited, but from the viewpoint of ensuring that the resin composition according to this embodiment satisfies the melt viscosity requirements described below and achieves both improved releasability from the chill roll and reduced neck-in, it is preferably 250,000 to 500,000, more preferably 300,000 to 450,000, and particularly preferably 350,000 to 400,000. Within the above range, the resin composition according to this embodiment has sufficient mechanical properties and the like, and it becomes easier to achieve both improved releasability from the chill roll and reduced neck-in.

[0024] The weight-average molecular weight of the P3HA-based resin (A) can be determined as a polystyrene-equivalent molecular weight by gel permeation chromatography (GPC) (Shodex GPC-101 manufactured by Showa Denko K.K.) using a polystyrene gel (Shodex K-804 manufactured by Showa Denko K.K.) as a column and chloroform as a mobile phase.

[0025] The microorganism that produces a P3HA resin is not particularly limited as long as it is capable of producing a P3HA resin. For example, the first P3HB-producing bacterium was Bacillus megaterium, discovered in 1925, and other natural microorganisms include Cupriavidus necator (formerly classified as Alcaligenes eutrophus, Ralstonia eutropha) and Alcaligenes latus. It is known that P3HB accumulates in the cells of these microorganisms.

[0026] Known bacteria that produce copolymers of hydroxybutyrate and other hydroxyalkanoates include Aeromonas caviae, which produces P3HB3HV and P3HB3HH, and Alcaligenes eutrophus, which produces P3HB4HB. In particular, with regard to P3HB3HH, in order to increase the productivity of P3HB3HH, Alcaligenes eutrophus AC32 strain (FERM BP-6038) (T. Fukui, Y. Doi, J. Bateriol., 179, pp. 4821-4830 (1997)) into which genes encoding P3HA synthases have been introduced is more preferred, and microbial cells obtained by culturing these microorganisms under appropriate conditions and allowing P3HB3HH to accumulate within the cells are used. In addition to the above, genetically modified microorganisms into which various P3HA resin synthesis-related genes have been introduced may be used depending on the P3HA resin to be produced, or the culture conditions, including the type of substrate, may be optimized.

[0027] P3HB3HH can also be produced by the method described in, for example, WO 2010 / 013483.

[0028] The resin composition according to the present embodiment may contain only one type of resin as the P3HA-based resin (A), or may contain a combination of two or more resins. When two or more types of resins (A) are combined, multiple resins having different types of constituent monomers may be used in combination, or multiple resins having different monomer composition ratios may be used in combination.

[0029] When at least two types of P3HA resins are used in combination, it is preferable to use a combination of at least one type of highly crystalline P3HA resin and at least one type of low-crystalline P3HA resin. Generally, highly crystalline P3HA resins have excellent processability but poor mechanical strength, while low-crystalline P3HA resins have poor processability but excellent mechanical properties. By using these resins in combination, a P3HA resin composition having both excellent processability and mechanical properties can be constructed.

[0030] When the highly crystalline P3HA-based resin contains 3-hydroxybutyrate units, the content of the 3-hydroxybutyrate units in the highly crystalline P3HA-based resin is preferably higher than the average content of the 3-hydroxybutyrate units in the entire P3HA-based resin (A). When the highly crystalline P3HA-based resin contains 3-hydroxybutyrate units and other hydroxyalkanoate units, the composition ratio of the monomer units in the highly crystalline resin is preferably 3-hydroxybutyrate units / other hydroxyalkanoate units = 90 / 10 to 99 / 1 (mol / mol), more preferably 92 / 8 to 98 / 2 (mol / mol), and even more preferably 94 / 6 to 97 / 3 (mol / mol).

[0031] As the highly crystalline P3HA-based resin, the above-mentioned P3HA-based resins can be used, but poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) are preferred.

[0032] Furthermore, the content of 3-hydroxybutyrate units contained in the low-crystalline P3HA-based resin is preferably lower than the average content of 3-hydroxybutyrate units in the entire P3HA-based resin (A). When the low-crystalline P3HA-based resin contains 3-hydroxybutyrate units and other hydroxyalkanoate units, the monomer unit composition ratio in the low-crystalline resin is preferably 3-hydroxybutyrate units / other hydroxyalkanoate units = 80 / 20 to 0 / 100 (mol / mol), more preferably 76 / 24 to 1 / 99 (mol / mol), even more preferably 76 / 24 to 50 / 50 (mol / mol), and particularly preferably 74 / 26 to 70 / 30 (mol / mol).

[0033] As the low-crystalline P3HA-based resin, the above-mentioned P3HA-based resins can be used, but poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) are preferred.

[0034] When a highly crystalline P3HA-based resin and a low-crystalline P3HA-based resin are used in combination, the content of the low-crystalline P3HA-based resin in the total of both resins is preferably 20 to 50% by weight, more preferably 20 to 40% by weight, and particularly preferably 25 to 35% by weight.

[0035] The resin composition according to this embodiment may contain one or more resins other than the P3HA-based resin (A) as long as the effects of the invention are achieved. Such other resins are preferably biodegradable resins, such as aliphatic polyester-based resins such as polybutylene succinate, polycaprolactone, and polylactic acid; aliphatic aromatic polyester-based resins such as polybutylene adipate terephthalate, polybutylene sebate terephthalate, and polybutylene azelate terephthalate; and polybutylene succinate adipate-based resins such as copolymers of polybutylene succinate adipate and polybutylene succinate adipate with lactic acid, terephthalic acid, malic acid, or sebacic acid.

[0036] To ensure the biodegradability of the resin composition, the amount of these other resins added is preferably 30 parts by weight or less per 100 parts by weight of the P3HA-based resin (A). It may also be 20 parts by weight or less, 10 parts by weight or less, or 5 parts by weight or less. There is no particular lower limit for the content of the other resins, and it may even be 0 parts by weight.

[0037] (Layered clay mineral (B)) The resin composition according to this embodiment further contains a layered clay mineral (B), which improves the releasability from the cooling roll after extrusion through a T-die and reduces neck-in.

[0038] The layered clay mineral refers to a mineral mainly composed of layered silicate. The layered clay mineral (B) is not particularly limited, and known ones can be used, but one or more selected from the group consisting of smectite, mica, talc, pyroferrite, vermiculite, chlorite, kaolinite, and serpentine are preferred because they are easy to achieve the neck-in reduction effect. From the viewpoint of versatility, mica, talc, and kaolinite are preferred, and talc is particularly preferred.

[0039] Examples of the mica include wet-ground mica and dry-ground mica. Examples of the talc include general-purpose talc and surface-treated talc. Examples of the kaolinite include dry kaolin, calcined kaolin, and wet kaolin.

[0040] The layered clay mineral (B) used has an average particle diameter D50 of 1 to 5 μm as determined by laser diffraction. This allows for both improved releasability from the chill roll and reduced neck-in. Furthermore, the mechanical properties of the resin film or resin layer formed from the resin composition according to this embodiment can be improved. If a layered clay mineral having an average particle diameter D50 exceeding 5 μm is used, neck-in can be reduced, but releasability from the chill roll is insufficient. The average particle diameter D50 is preferably 1.2 to 4 μm, and more preferably 1.5 to 3 μm. In particular, in an embodiment in which the aforementioned highly crystalline P3HA-based resin and a low-crystalline P3HA-based resin are used in combination, releasability from the chill roll can be further improved when the layered clay mineral (B) has an average particle diameter D50 of 2 μm or more. The average particle diameter D50 of the layered clay mineral (B) can be measured as the median diameter (D50) using a laser diffraction / scattering type particle size distribution measuring device such as the "Microtrac MT3100II" manufactured by Nikkiso Co., Ltd.

[0041] In order to achieve the function as a crystal nucleating agent for the P3HA-based resin (A), the layered clay mineral (B) should have a specific surface area of ​​10 to 40 m ２ The specific surface area is 12 to 38 m / g. ２ / g, and more preferably 15 to 35m ２ The specific surface area can be measured by the BET method.

[0042] The blending amount of the layered clay mineral (B) is 0.3 to 3 parts by weight per 100 parts by weight of the P3HA-based resin (A). By blending the layered clay mineral within this range, it is possible to achieve both improved releasability from the chill roll after T-die extrusion and reduced neck-in. The mechanical properties of the resin film or resin layer can also be improved. If the blending amount of the layered clay mineral (B) is less than 0.3 parts by weight, the neck-in reduction effect tends to be insufficient, while if it exceeds 3 parts by weight, poor dispersion of the layered clay mineral (B) tends to reduce releasability from the chill roll. The blending amount of the layered clay mineral (B) is preferably 0.5 to 2.5 parts by weight, more preferably 1 to 2 parts by weight.

[0043] (Aliphatic Amide Compound (C)) Aliphatic amide compounds are a type of additive conventionally known as lubricants added to resins. The aliphatic amide compound (C) is not particularly limited, and examples thereof include saturated or unsaturated fatty acid amides such as lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, and erucic acid amide, and alkylene fatty acid amides such as methylene bisstearic acid amide and methylene bisstearic acid amide. Of these, behenic acid amide and erucic acid amide are preferred from the viewpoint of improving releasability from a cooling roll. The aliphatic amide compound may be used alone or in combination.

[0044] The amount of the aliphatic amide compound (C) is 0.3 to 3 parts by weight per 100 parts by weight of the P3HA-based resin (A). By incorporating the aliphatic amide compound (C) in an amount of 0.3 parts by weight or more, the effect of improving the releasability from the chill roll can be achieved. However, if the amount of the aliphatic amide compound (C) exceeds 3 parts by weight, the component bleeds out and adheres to the surface of the chill roll, etc., making long-term continuous processing difficult. The amount of the aliphatic amide compound (C) is preferably 0.5 to 2.5 parts by weight, more preferably 1 to 2 parts by weight.

[0045] (Crystal Nucleating Agent) The resin composition according to this embodiment may contain a crystal nucleating agent other than the layered clay mineral and the aliphatic amide compound (hereinafter also referred to as "other crystal nucleating agent"). Examples of other crystal nucleating agents include sugar alcohols such as pentaerythritol, galactitol, and mannitol; orotic acid, aspartame, cyanuric acid, glycine, zinc phenylphosphonate, and boron nitride. One or more crystal nucleating agents may be used, and the ratio of use can be appropriately adjusted depending on the purpose.

[0046] When other crystal nucleating agents are used, the amount thereof is not particularly limited, but is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, per 100 parts by weight of the P3HA resin (A).

[0047] However, the resin composition according to this embodiment may be substantially free of other nucleating agents (particularly sugar alcohols or pentaerythritol). "Substantially free of other nucleating agents" means that the amount of other nucleating agents added is less than 0.1 parts by weight per 100 parts by weight of the P3HA-based resin (A). It may even be less than 0.01 parts by weight. In an embodiment in which other nucleating agents are not added substantially, the problems of bleeding out of other nucleating agents and the resulting contamination of the chill roll surface can be avoided. Because the resin composition according to this embodiment contains the layered clay mineral (B) and the fatty acid amide compound (C), good releasability from the chill roll can be achieved even when other nucleating agents are not added substantially.

[0048] In addition to the layered clay mineral (B) and the fatty acid amide compound (C), the resin composition according to this embodiment may contain additives commonly used in the art, provided that the effects of the invention are achieved. Examples of such additives include inorganic fillers such as calcium carbonate, silica, titanium oxide, and alumina; organic fillers such as rice husk, wood flour, and recycled paper such as newspaper; various starches and cellulose; colorants such as pigments and dyes; odor absorbers such as activated carbon and zeolite; fragrances such as vanillin and dextrin; plasticizers; antioxidants; weather resistance improvers; UV absorbers; lubricants; release agents; water repellents; antibacterial agents; and sliding properties improvers. Only one type of additive may be contained, or two or more types may be contained. The content of these additives can be appropriately determined by those skilled in the art depending on the intended use.

[0049] The proportion of the P3HA-based resin (A) in the resin composition according to this embodiment is not particularly limited, but may be 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, or 95% by weight or more of the total amount of the resin composition.

[0050] The resin composition according to this embodiment was heated at 175°C and a shear rate of 122 s －１This indicates that the melt viscosity measured by JIS K 1995-1999 is 300 Pa.s or more and 1000 Pa.s or less. When the melt viscosity is within this range, shear heat generation in the extruder is suppressed, making it easier to leave crystal nuclei in the molten resin necessary for promoting crystallization when contacting the chill roll. When the melt viscosity is less than 300 Pa.s, the releasability from the chill roll may be insufficient, and the effect of reducing neck-in may not be sufficiently obtained. On the other hand, when the melt viscosity exceeds 1000 Pa.s, the releasability from the chill roll may be insufficient, making continuous production difficult. The melt viscosity is preferably 350 Pa.s or more and 900 Pa.s or less, more preferably 400 Pa.s or more and 800 Pa.s or less, and more preferably 500 Pa.s or more and 700 Pa.s or less.

[0051] The melt viscosity of the resin composition according to this embodiment can be controlled by adjusting the monomer composition ratio of the P3HA-based resin (A), the weight-average molecular weight of the P3HA-based resin (A), the amount of components other than the P3HA-based resin (A), and the like.

[0052] The resin composition according to this embodiment is used for T-die extrusion molding. Specifically, it can be used for producing a film by melt extrusion molding using a T-die, or for producing a laminate by extruding a molten resin composition from a T-die and directly laminating it onto a substrate layer. Details will be described later.

[0053] The laminate according to the present embodiment includes a base layer and a resin layer containing the resin composition, the resin layer being laminated on at least one side of the base layer. The surface condition of the resin layer is good, making the laminate advantageous in various applications.

[0054] In the present laminate, the resin layer may be laminated on only one side of the substrate layer or on both sides. The resin layer may be laminated on the substrate layer via another layer, or may be laminated directly on the substrate layer without any other layer. Furthermore, another layer may be laminated on the resin layer.

[0055] (Substrate layer) The present laminate includes a substrate layer. The substrate layer in the present laminate is not particularly limited as long as it is a layer on which a resin layer can be laminated, but it is preferably a layer having biodegradability. This makes the present laminate as a whole, including the resin layer, biodegradable, making it more advantageous as a material for solving the problem of marine pollution.

[0056] The biodegradable substrate layer is not particularly limited, but examples include paper (mainly composed of cellulose), cellophane, cellulose ester; polyvinyl alcohol, polyamino acid, polyglycolic acid, pullulan, or a substrate having inorganic materials such as aluminum or silica vapor-deposited thereon. Among these, paper is preferred because of its excellent heat resistance and low cost. The type of paper is not particularly limited, and examples include cup base paper, kraft paper, fine paper, coated paper, tissue paper, glassine paper, and paperboard. The type of paper can be appropriately selected depending on the application of the laminate. Water-resistant agents, water-repellent agents, inorganic materials, etc. may be added to the paper as needed, and the paper may be surface-treated with an oxygen barrier layer coating, a water vapor barrier coating, etc.

[0057] The substrate layer may be subjected to a surface treatment such as corona treatment, plasma treatment, ozone treatment, flame treatment, anchor coating treatment, etc. These surface treatments may be performed alone or in combination. In particular, by subjecting the substrate layer to corona treatment in-line during lamination processing and then laminating a resin layer on the substrate layer, the adhesive strength between the P3HA resin (A) and the substrate layer can be increased.

[0058] (Resin Layer) The resin layer in the present laminate is composed of the resin composition according to this embodiment. The resin layer may contain components other than the resin composition according to this embodiment, as long as the effects of the invention are not impaired. The content of such additives can be appropriately determined by those skilled in the art depending on the purpose of use.

[0059] (Method for manufacturing laminate) The laminate according to this embodiment is not particularly limited, but can be manufactured, for example, by forming a resin layer (laminate layer) containing a P3HA-based resin on one or both sides of a substrate layer such as paper by a lamination method. The lamination method is a method for manufacturing a laminate by using a pressure-bonding surface to press-bond the resin layer containing a P3HA-based resin to the substrate layer, and then peeling the resin layer containing a P3HA-based resin from the pressure-bonding surface. The pressure-bonding surface may be any surface that can press-bond the resin layer containing a P3HA-based resin to the substrate layer, and examples of the surface include a plate-like surface and the surface of a roll.

[0060] The lamination method is not particularly limited, but specific examples include an extrusion lamination method in which a molten resin composition is extruded from a T-die in the form of a film, directly laminated onto a separately unwound substrate layer such as paper, and cooled and pressed using a cooling roll; and a lamination method (specifically, a dry lamination method, a non-solvent lamination method, or a thermal lamination method) in which a film is produced by melt extrusion molding using a T-die, and then the film is placed on at least one side of a substrate layer and pressed.

[0061] The heating temperature in the lamination method (hereinafter also referred to as lamination temperature) is preferably in the range of the temperature of the resin composition according to this embodiment during lamination, which is equal to or higher than the melting point (Tm) of the P3HA-based resin (A) and equal to or lower than a temperature (Tm + 30) 30°C higher than the melting point (Tm). The melting point refers to the top temperature of the melting point peak on the highest temperature side in the crystalline melting curve obtained by differential scanning calorimetry. If the lamination temperature is lower than the melting point, the resin cannot be sufficiently fluidized, and thickness unevenness of the resin film or resin layer tends to increase. Furthermore, if the lamination temperature exceeds a temperature 30°C higher than the melting point, the solidification rate of the resin film or the resin layer after lamination slows, and as a result, sufficient releasability from the cooling roll tends to be impaired.

[0062] Specifically, the lamination temperature is preferably 160° C. or higher, more preferably 165° C. or higher. The upper limit of the lamination temperature is preferably 180° C. or lower. When the lamination temperature is 180° C. or lower, a decrease in the mechanical strength of the resin film or resin layer due to thermal decomposition of the P3HA-based resin (A) tends to be avoided.

[0063] The lamination temperature may be set so that the temperature of the resin composition containing the P3HA resin is within the above range during lamination. For example, in the case of extrusion lamination, the temperature of the T-die may be adjusted, and in the case of thermal lamination, the temperature of the heating roll used to bond the films may be adjusted.

[0064] In the lamination method, the surface temperature of the chill roll that comes into contact with the resin composition immediately after it has been extruded in a molten state from a T-die may be any temperature that allows for molding of a resin film or cooling and pressing of a resin layer, but is preferably 55 to 65° C., more preferably 57 to 62° C. Within the above range, crystallization of the P3HA resin (A) is promoted, resulting in reduced adhesion to the chill roll and enabling solidification to be achieved in a short period of time.

[0065] Although a metal roll can be suitably used as the cooling roll, in order to avoid blocking with the resin film or resin layer, a roll whose surface has been subjected to blasting or release coating treatment may be used. Examples of release coating treatment include fluorine-based coating, ceramic coating, and Tosical Coat (registered trademark of Toshiko Co., Ltd.).

[0066] The thickness of the film according to this embodiment or the thickness of the resin layer of the laminate according to this embodiment is not particularly limited, but from the viewpoint of preventing water absorption into the base layer while ensuring sufficient flexibility, it is preferably 5 to 300 μm, and more preferably 10 to 200 μm.

[0067] As a substrate layer, 150 to 350 g / m ２When the cup base paper is used, the thickness of the resin layer is preferably 20 to 100 μm, and more preferably 30 to 70 μm. By keeping the thickness within this range, secondary processability such as punching property and heat sealing property can be maintained good.

[0068] [Molded Product] The molded product according to this embodiment includes the laminate described above. This molded product is advantageous in various applications because it is formed from a laminate in which the resin layer has a good surface condition.

[0069] The present molded article is not particularly limited as long as it contains the laminate, and examples thereof include paper, film, sheet, tube, plate, rod, container (e.g., bottle container), bag, part, etc. From the viewpoint of measures against marine pollution, the present molded article is preferably a bag or a bottle container.

[0070] The present molded article may be the laminate itself, or may be a laminate that has been subjected to secondary processing. By subjecting the present laminate to secondary processing, the present molded article containing the laminate can be suitably used as various packaging container materials such as shopping bags, various bags, food and confectionery packaging materials, cups, trays, cartons, etc. (in other words, in various fields such as food, cosmetics, electronics, medicine, and pharmaceuticals). Because the present laminate contains a resin composition that has high adhesion to substrates and good heat resistance, it is more suitable as a container for holding liquids, particularly containers for holding hot contents, such as cups for food and beverages such as instant noodles, instant soup, and coffee, trays for prepared meals, bento boxes, and microwaveable foods.

[0071] The secondary processing can be carried out by any method known in the technical field, for example, using various bag-making machines, filling and packaging machines, etc. Processing can also be carried out using devices such as a paper tray press molding machine, a paper cup molding machine, a punching machine, and a box making machine. In these processing machines, known techniques can be used to bond the molded body, and in addition to the usual heat sealing method, for example, an impulse sealing method, an ultrasonic sealing method, a high-frequency sealing method, a hot air sealing method, a frame sealing method, etc. can be used. The heat sealing may be carried out between the substrate layer and the resin layer, or may be carried out between the resin layers.

[0072] The heat sealing temperature when heat sealing the resin layers of the laminate together is, when heated on both sides using a heating type heat seal tester equipped with a seal bar, usually 150 to 200°C, preferably 160 to 190°C, and more preferably 170 to 180°C. The heat sealing temperature when heat sealing the resin layer and base layer of the laminate is, when heated on both sides using a heating type heat seal tester equipped with a seal bar, usually 160 to 220°C, preferably 170 to 210°C, and more preferably 180 to 200°C. Within the above range, melting of the resin near the sealed portion can be avoided, and an appropriate resin layer thickness and seal strength can be ensured.

[0073] The heat-sealing pressure when heat-sealing the laminate varies depending on the adhesion method. When a heat-sealing tester equipped with a seal bar is used, the heat-sealing pressure of the molded product is usually 0.1 MPa or more, preferably 0.3 MPa or more. When the pressure is above this value, sufficient adhesive strength can be ensured by heat sealing.

[0074] In order to improve the physical properties of the molded article according to this embodiment, it is also possible to compound the molded article with another molded article (for example, fiber, thread, rope, woven fabric, knitted fabric, nonwoven fabric, paper, film, sheet, tube, plate, rod, container, bag, part, foam, etc.) made of a different material from the molded article. These materials are also preferably biodegradable.

[0075] The film, laminate, or molded article according to this embodiment can be suitably used in the fields of agriculture, fisheries, forestry, horticulture, medicine, hygiene products, clothing, non-clothing, packaging, automobiles, building materials, and other fields.

[0076] The following items are preferred embodiments of the present disclosure, but the present invention is not limited to the following items. [Item 1] 100 parts by weight of a poly(3-hydroxyalkanoate) resin (A), an average particle diameter D50 determined by a laser diffraction method of 1 to 5 μm, and a specific surface area determined by a BET method of 10 to 40 m ２ / g of layered clay mineral (B) 0.3 to 3 parts by weight, and 0.3 to 3 parts by weight of fatty acid amide compound (C),－１A resin composition for T-die extrusion molding, having a melt viscosity of 300 to 1000 Pa s as measured by HPLC. [Item 2] The resin composition for T-die extrusion molding according to Item 1, wherein the poly(3-hydroxyalkanoate) resin (A) contains 50% by weight or more of a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of the other hydroxyalkanoate units being 1 to 10 mol %. [Item 3] The resin composition for T-die extrusion molding according to Item 1 or 2, wherein the poly(3-hydroxyalkanoate) resin (A) contains a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of the other hydroxyalkanoate units being 24 mol % or more. [Item 4] The resin composition for T-die extrusion molding according to Item 2 or 3, wherein the other hydroxyalkanoate units are 3-hydroxyhexanoate units. [Item 5] The resin composition for T-die extrusion molding according to any one of Items 1 to 4, wherein the poly(3-hydroxyalkanoate) resin (A) has a weight-average molecular weight of 250,000 to 500,000. [Item 6] The resin composition for T-die extrusion molding according to any one of Items 1 to 5, which is substantially free of pentaerythritol. [Item 7] A T-die extrusion film comprising the resin composition for T-die extrusion molding according to any one of Items 1 to 6. [Item 8] A laminate comprising a T-die extrusion resin layer comprising the resin composition for T-die extrusion molding according to any one of Items 1 to 6, and a substrate layer. [Item 9] The laminate according to Item 8, wherein the substrate layer is biodegradable. [Item 10] The laminate according to Item 8 or 9, wherein the substrate layer is paper. [Item 11] A molded product comprising the laminate according to any one of Items 8 to 10. [Item 12] A method for producing a film, comprising the step of melt-extrusion molding the resin composition for T-die extrusion molding according to any one of Items 1 to 6, using a T-die. [Item 13] A method for producing the laminate according to any one of Items 8 to 10, comprising forming the resin layer on at least one surface of the base material layer by extrusion lamination using a T-die.[Item 14] A method for producing the laminate according to any one of Items 8 to 10, comprising the steps of melt-extrusion molding the resin composition for T-die extrusion molding using a T-die to form a film, and disposing the film on at least one surface of the base layer and forming the resin layer by any one of dry lamination, non-solvent lamination, and thermal lamination. [Item 15] The production method according to Item 13 or 14, wherein the heating temperature during extrusion is from the melting point (Tm) of the poly(3-hydroxyalkanoate) resin (A) to the melting point (Tm) + 30°C, and the temperature of the cooling roll is 55 to 65°C.

[0077] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0078] The raw materials for the resin compositions for T-die extrusion molding used in the examples and comparative examples are shown below. [Poly(3-hydroxyalkanoate)-based resin] P3HB3HH-1 to P3HB3HH-3 below were produced according to the methods described in Production Examples 3 and 4 of International Publication WO 2019 / 239913. P3HB3HH-1: P3HB3HH (average content ratio 3HB / 3HH = 94 / 6 (mol% / mol%), weight average molecular weight is 400,000 g / mol) P3HB3HH-2: P3HB3HH (average content ratio 3HB / 3HH = 94 / 6 (mol% / mol%), weight average molecular weight is 600,000 g / mol) P3HB3HH-3: P3HB3HH (average content ratio 3HB / 3HH = 94 / 6 (mol% / mol%), weight average molecular weight is 200,000 g / mol) P3HB3HH-4: P3HB3HH [average content ratio 3HB / 3HH = 72 / 28 (mol% / mol%), weight average molecular weight is 600,000 g / mol] It was produced in accordance with the method described in Example 9 of International Publication WO2019 / 142845.

[0079] [Layered clay minerals] Talc 1: MicroAce SG-200N15 (average particle diameter D50 = 1.5 μm, specific surface area = 35 m) manufactured by Nippon Talc Co., Ltd. ２ / g) Talc 2: MicroAce SG-95 (average particle diameter D50 = 2.1 μm, specific surface area = 15 m) manufactured by Nippon Talc Co., Ltd. ２ / g) Talc 3: MicroAce K-1 (average particle diameter D50 = 8.0 μm, specific surface area = 7 m) manufactured by Nippon Talc Co., Ltd. ２ / g) The average particle diameter D50 of the layered clay mineral is a value measured as the median diameter (D50) using a laser diffraction / scattering particle size distribution measuring device [Microtrac MT3100II manufactured by Nikkiso Co., Ltd.].

[0080] [Aliphatic amide compound] Behenamide BNT-22H manufactured by Nippon Fine Chemical Co., Ltd.

[0081] The evaluation methods used in the examples and comparative examples are described below. [Method for measuring melt viscosity] A capillograph (cylinder diameter 10 mm) equipped with an orifice having a diameter of 1 mm, a length of 10 mm, and an inlet angle of 90° and heated to 175°C was filled with 15 g of resin pellets, and after preheating for 5 minutes, the piston was lowered at a rate of 10 mm / min. The melt viscosity at a shear rate of 122 / s was calculated from the stress applied to the piston when the molten resin was extruded from the orifice.

[0082] [Removability from Chill Roll] The degree of adhesion of the resin film extruded from the T-die to the chill roll was observed. The evaluation criteria were as follows. <Evaluation> ⊚: The resin film was continuously and smoothly taken up without tension when peeling from the chill roll. ◯: Some tension was applied when peeling from the chill roll, but the resin film was continuously and smoothly taken up. Δ: The resin film could be continuously peeled from the chill roll, but wrinkles occurred in the film. ×: The resin was not sufficiently crystallized and could not be molded.

[0083] [Neck-in] The width of the obtained film was measured at 50 mm intervals in the unwinding direction, and the neck-in ((T-die opening width - average film width) x 1 / 2) was evaluated based on the average value according to the following criteria: <Evaluation> ◯: Less than 80 mm ×: 80 mm or more

[0084] Example 1 Each component was dry blended (resin components were mixed in a non-molten state) with 100 parts by weight of P3HB3HH-1 at the compounding ratio shown in Table 1 (compounding ratios in the table are shown in parts by weight). The resulting compound was then melt-kneaded and extruded into a strand using a twin-screw extruder with the cylinder and die set to 150°C. The strand was then immersed in a water bath heated to 40°C to crystallize and solidify, and then cut with a pelletizer to prepare resin pellets for T-die extrusion molding. The melt viscosity of the resulting resin pellets was measured and the results are shown in Table 1.

[0085] Subsequently, the obtained resin pellets were thoroughly dried at 60 ° C., and then fed into a single-screw extruder equipped with a T-type die having an opening width of 500 mm and a lip clearance of 0.7 mm, extruded, sandwiched between a metal roll (roll diameter 150 mm) and a rubber roll (roll diameter 150 mm) and taken up at 5 m / min to form a film having a thickness of 40 μm. The peelability from the cooling roll and neck-in were evaluated. The cylinder and die of the extruder were set to 170 ° C., the cooling roll was set to 60 ° C., and the air gap (the distance from the die outlet to the contact of the molten resin film with the cooling roll) was 90 mm. The results are shown in Table 1.

[0086] (Examples 2 to 4, Comparative Examples 1 to 5) Resin pellets were prepared in the same manner as in Example 1 except that the resin formulation was changed as shown in Table 1, and evaluations were carried out in the same manner as in Example 1. The results are summarized in Table 1.

[0087]

[0088] [Results] As can be seen from Table 1, Examples 1 to 4 achieved good results in the evaluation of releasability from the chill roll and neck-in. On the other hand, Comparative Example 1 did not contain the layered clay mineral (B), and the neck-in evaluation was poor. In Comparative Example 2, the amount of layered clay mineral (B) was increased to 5 parts by weight, but the releasability from the chill roll was poor. In Comparative Example 3, a layered clay mineral (B) with a large average particle diameter D50 of 8.0 μm was used, and the releasability from the chill roll was poor. In Comparative Example 4, a resin composition with a high melt viscosity of 1060 Pa.s under specific conditions was used, and the releasability from the chill roll was poor. In Comparative Example 5, a resin composition with a low melt viscosity of 290 Pa.s was used, and both the releasability from the chill roll and the neck-in were poor.

Claims

1. 100 parts by weight of poly(3-hydroxyalkanoate) resin (A), an average particle diameter D50 measured by a laser diffraction method of 1 to 5 μm and a specific surface area measured by a BET method of 10 to 40 m ２ / g layered clay mineral (B) 0.3 to 3 parts by weight, and a fatty acid amide compound (C) 0.3 to 3 parts by weight, －１ The resin composition for T-die extrusion molding has a melt viscosity of 300 to 1000 Pa.s as measured by 2. A resin composition for T-die extrusion molding as described in claim 1, wherein the poly(3-hydroxyalkanoate) resin (A) contains 50% by weight or more of a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 1 to 10 mol %.

3. A resin composition for T-die extrusion molding according to claim 2, wherein the poly(3-hydroxyalkanoate) resin (A) comprises a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 24 mol % or more.

4. The resin composition for T-die extrusion molding according to claim 2, wherein the other hydroxyalkanoate units are 3-hydroxyhexanoate units.

5. A resin composition for T-die extrusion molding according to any one of claims 1 to 4, wherein the poly(3-hydroxyalkanoate) resin (A) has a weight average molecular weight of 250,000 to 500,000.

6. The resin composition for T-die extrusion molding according to any one of claims 1 to 4, which is substantially free of pentaerythritol.

7. A T-die extrusion molding film comprising the resin composition for T-die extrusion molding according to claim 1.

8. A laminate comprising a resin layer for T-die extrusion molding, which comprises the resin composition for T-die extrusion molding according to claim 1, and a substrate layer.

9. The laminate according to claim 8, wherein the substrate layer is biodegradable.

10. The laminate of claim 8, wherein the substrate layer is paper.

11. A molded article comprising the laminate according to claim 8.

12. A method for producing a film, comprising the step of melt-extrusion molding the resin composition for T-die extrusion molding according to claim 1 using a T-die.

13. A method for producing the laminate according to claim 8, comprising the step of forming the resin layer on at least one surface of the base layer by an extrusion lamination method using a T-die.

14. A method for producing the laminate described in claim 8, comprising the steps of: forming the resin composition for T-die extrusion molding into a film by melt extrusion molding using a T-die; and placing the film on at least one side of the base layer and forming the resin layer by any one of a dry lamination method, a non-solvent lamination method, and a thermal lamination method.

15. The method according to claim 13 or 14, wherein the heating temperature during extrusion is from the melting point (Tm) of the poly(3-hydroxyalkanoate) resin (A) to the melting point (Tm) + 30°C, and the temperature of the cooling roll is 55 to 65°C.

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