Laminate, method for manufacturing the same, and molded body

Abstract

This layered body comprises, in order, a substrate layer (A), an adhesive resin layer (B), and a resin layer (D) containing a copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate. The basis weight of the adhesive resin layer (B) is 0.1 g / m2 or greater but less than 3.0 g / m2; the average content ratio of 3-hydroxyhexanoate in the copolymer (C) is 6 mol% or greater; and the thickness of the resin layer (D) is 20 μm or greater but less than 100 μm.

Description

[Technical Field]

[0001] The present invention relates to a laminate comprising a resin layer laminated on at least one side of a substrate layer such as paper, a method for manufacturing the same, and a molded article. [Background technology]

[0002] In recent years, environmental problems caused by plastic waste have come into sharp focus. In particular, marine pollution caused by plastic waste is serious, and the widespread use of biodegradable plastics that decompose in the natural environment is highly anticipated.

[0003] While various types of biodegradable plastics are known, among them, the copolymer of 3-hydroxybutyrate (hereinafter sometimes referred to as "3HB") and 3-hydroxyhexanoate (hereinafter sometimes referred to as "3HH") (hereinafter sometimes referred to as "PHBH") is attracting attention as a material that can solve the above problems because it is a thermoplastic polyester that is produced and stored as an energy storage substance in the cells of many microbial species, and can biodegrade not only in soil but also in seawater. In particular, PHBH / paper composite materials, which integrate PHBH with a base material such as paper, are attracting significant social attention because they can be applied to food contact containers and other applications that have a low environmental impact.

[0004] Methods for integrating PHBH with paper include extrusion lamination and aqueous slurry coating. However, the extrusion lamination method is preferred because the coating method does not easily provide sufficient mechanical strength for the resin layer. However, PHBH generally has a high melt viscosity and does not adhere well to paper, making it difficult to bond extruded PHBH to paper with sufficient strength. As a result, in the manufacturing process of cup molded products such as beverage cups, the laminate layer would peel off from the paper, causing leakage when the contents were filled.

[0005] Although PHBH is not disclosed in Patent Document 1, a polycaprolactone dispersion or emulsion is applied to the paper at a rate of 10 g / m² with the aim of improving the adhesion of the biodegradable resin to the paper and thereby improving the lamination strength. 2 A method is disclosed in which a 3-hydroxybutyric acid-3-hydroxyvaleric acid copolymer (PHBV) is laminated by extrusion lamination after coating with a basis weight (dry weight of the layer) and drying. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-293113 [Overview of the project] [Problems that the invention aims to solve]

[0007] According to the method in Patent Document 1, the adhesion between the paper and the resin layer tends to improve, but the polycaprolactone dispersion or emulsion is 10 g / m². 2 Because the coating is applied in such a large amount, and then dried, the drying process takes a long time, resulting in low productivity. Furthermore, the drying process can cause the paper substrate to deteriorate, or the paper to dry out too much, causing the laminate to warp.

[0008] To facilitate drying, the basis weight of the adhesive layer is set to 10 g / m². 2 While there are methods to reduce the amount, these methods present challenges such as insufficient adhesion between the paper substrate and the resin layer.

[0009] In view of the above situation, the present invention aims to provide a laminate comprising, in this order, a base layer, an adhesive layer, and a resin layer containing a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate, wherein the adhesive layer has good drying properties when formed and high adhesive strength between the base layer and the resin layer. [Means for solving the problem]

[0010] As a result of diligent research to solve the above problems, the present inventors have found that in a laminate comprising a base layer (A), an adhesive resin layer (B), and a resin layer (D) containing a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate in this order, the above problems can be solved by setting the thickness of the resin layer (D) within a specific range while sufficiently reducing the basis weight of the adhesive resin layer (B), and have completed the present invention.

[0011] In other words, the present invention relates to a laminate comprising, in this order, a base layer (A), an adhesive resin layer (B), and a resin layer (D) containing a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (C), wherein the basis weight of the adhesive resin layer (B) is 0.1 g / m². 2 More than 3.0g / m 2 The present invention relates to a laminate in which the average content ratio of 3-hydroxyhexanoate in the copolymer (C) is 6 mol% or more, and the thickness of the resin layer (D) is 20 μm or more and less than 100 μm. Furthermore, the present invention relates to a method for manufacturing the aforementioned laminate, The present invention also relates to a manufacturing method comprising a first step of forming the adhesive resin layer (B) on at least one side of the substrate layer by a coating method, and a second step of forming the resin layer (D) on the surface of the adhesive resin layer (B) by an extrusion lamination method or a heat lamination method. [Effects of the Invention]

[0012] According to the present invention, a laminate comprising a base layer, an adhesive layer, and a resin layer containing a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate, in this order, can be provided, which has good drying properties when forming the adhesive layer and high adhesive strength between the base layer and the resin layer. By using this laminate, it is possible to improve the production efficiency and quality of molded articles. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram showing the laminated structure of the laminate according to this embodiment.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0015] [Laminate] The laminate according to one embodiment of the present invention has an adhesive resin layer (B) and a resin layer (D) containing a copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate on at least one side of a base material layer (A). As shown in FIG. 1, in the laminate 1, the base material layer (A) indicated by reference numeral 2, the adhesive resin layer (B) indicated by reference numeral 3, and the resin layer (D) indicated by reference numeral 4 are laminated in this order.

[0016] The adhesive resin layer (B) may be directly laminated on the base material layer (A), and as long as the adhesiveness is not inhibited, another resin layer may be further included as an intermediate layer between the adhesive resin layer (B) and the base material layer (A).

[0017] The laminate may have the adhesive resin layer (B) and the resin layer (D) only on one side of the base material layer (A), or may have the adhesive resin layer (B) and the resin layer (D) on both sides of the base material layer (A).

[0018] When the laminate has the adhesive resin layer (B) and the resin layer (D) only on one side of the base material layer (A), no other layer is formed on the other side, and the base material layer (A) may be the outermost layer exposed on the surface of the laminate, or another layer may be laminated for the purpose of imparting water resistance, gloss, or adhesiveness.

[0019] When the laminate has the adhesive resin layer (B) and the resin layer (D) on both sides of the base material layer (A), the materials, basis weights, and thicknesses of the adhesive resin layer (B) on the front side and the adhesive resin layer (B) on the back side may be the same as or different from each other. The same applies to the resin layer (D) on the front side and the resin layer (D) on the back side. In addition, the basis weight (g / m 2This refers to the dry weight (solid content) of the layer.

[0020] [Base material layer (A)] The material constituting the base layer (A) is not particularly limited, but it is preferably biodegradable. Examples include paper (whose main component is cellulose), cellophane, cellulose ester; polyvinyl alcohol, polyamino acids, polyglycolic acid, pullulan, or these base materials with inorganic materials such as aluminum or silica deposited on them. Among these, paper is preferred because it has excellent heat resistance and is inexpensive.

[0021] The type of paper is not particularly limited and can be appropriately selected depending on the application of the laminate, but examples include cup paper, kraft paper, fine paper, coated paper, tissue paper, glassine paper, and cardboard. The paper may have water-resistant agents, water-repellent agents, inorganic substances, etc. added as needed, and may also be surface-treated with oxygen barrier coatings, water vapor barrier coatings, etc.

[0022] Furthermore, the substrate layer (A) may be subjected to surface treatments such as corona treatment, ozone treatment, plasma treatment, flame treatment, anchor coating, oxygen barrier layer coating, or water vapor barrier coating. These surface treatments may be performed individually or in combination.

[0023] [Adhesive resin layer (B)] The adhesive resin layer (B) is a layer composed mainly of a resin. The main resin contained in the adhesive resin layer (B) is not particularly limited, and resins commonly used in the field of coated paper or resin films can be preferably used. It is desirable that at least one resin having a high affinity for a substrate such as paper and PHBH be included. Examples of such resins include acrylic resins, methacrylic resins, vinyl chloride resins, styrene-acrylic resins, styrene-butadiene resins, styrene-isoprene resins, polycarbonate resins, urea resins, melamine resins, epoxy resins, phenolic resins, urethane resins, diallyl phthalate resins, imine resins, and the like. These can be used alone, or two or more resins can be mixed and used at an arbitrary ratio.

[0024] The resin contained in the adhesive resin layer (B) may be water-soluble or soluble in an organic solvent. When using a resin insoluble in water, other additives can be added to improve the dispersibility and coating properties in water. When coating an aqueous emulsion, aqueous slurry, or water-soluble resin, the solid content concentration of the resin is not particularly limited, but it is preferably 30% by weight or more, more preferably 40% by weight or more, and even more preferably 50% by weight or more in order to keep the heat required for drying low. Also, from the viewpoint of avoiding sedimentation of the dispersed resin and achieving good coating properties, the solid content concentration is preferably 60% by weight or less.

[0025] In the laminate according to the present embodiment, the basis weight of the adhesive resin layer (B) is adjusted within the range of 0.1 g / m 2 or more and less than 3.0 g / m 2 If the basis weight is less than 0.1 g / m 2 , the adhesiveness with the resin layer (D) may decrease. Conversely, if it exceeds 3.0 g / m 2 , a large amount of heat is required during drying, resulting in a large load on the equipment, or problems such as blocking during original web winding may occur due to poor drying. The basis weight is 0.5 g / m 2 or more and 2.5 g / m2 It is more preferable that the following conditions apply: 1.0 g / m 2 More than 2.0g / m 2 The following is even more preferable:

[0026] [Resin layer (D)] The resin layer (D) comprises a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (hereinafter sometimes referred to as "PHBH") (C). The resin layer (D) may also be the outermost layer in the laminate according to this embodiment, in which case the resin layer (D) can be used for heat sealing (described later).

[0027] PHBH is a particularly useful plastic industrially because its melting point and degree of crystallinity can be altered by changing the ratio of repeating units, thereby easily adjusting physical properties such as Young's modulus and heat resistance, and it can also impart properties between those of polypropylene and polyethylene.

[0028] The specific manufacturing method of PHBH is described, for example, in International Publication No. 2010 / 013483. Commercially available PHBH products include Kaneka Corporation's "Kaneka Biodegradable Polymer Green Planet" (registered trademark).

[0029] The average content ratio of each constituent monomer in PHBH(C) is preferably 3HB / 3HH = 94-80 / 6-20 (mol% / mol%), and more preferably 3HB / 3HH = 90-82 / 10-18 (mol% / mol%). If the average content ratio of 3HH in PHBH(C) is 6 mol% or more, good adhesion to the adhesive resin layer (B) formed on a substrate such as paper can be achieved. Furthermore, if the average content ratio of 3HH is 20 mol% or less, the crystallization rate of PHBH does not become too slow, and production is relatively easy.

[0030] The average content ratio of each constituent monomer in PHBH(C) refers to the molar ratio of 3HB to 3HH contained in PHBH(C). If PHBH(C) is a mixture of at least two types of PHBH with different content ratios of constituent monomers, or a mixture containing at least one type of PHBH and PHB, it refers to the molar ratio of each constituent monomer contained in the entire mixture. The average content ratio of the constituent monomers can be determined by methods known to those skilled in the art, for example, the method described in paragraph

[0047] of International Publication 2013 / 147139, or by NMR measurement.

[0031] As described above, the PHBH(C) contained in the resin layer (D) may include at least two types of PHBH having different constituent monomer content ratios, and may also further include PHB (a homopolymer of 3-hydroxybutyrate) in addition to at least one type of PHBH.

[0032] When at least two types of PHBH are included, it is preferable to include a highly crystalline and high-melting-point PHBH with a 3HH content of less than 6 mol%, and a low-crystalline and low-melting-point PHBH with a 3HH content of 15 mol% or more.

[0033] In particular, the PHBH(C) contained in the resin layer (D) preferably contains at least two types of PHBH components: a first melting point component (low crystalline component) with a melting point of 60°C or higher and less than 90°C, and a second melting point component (high crystalline component) with a melting point of 140°C or higher and less than 170°C. In particular, the melting point of the first melting point component is preferably 65°C or higher and 85°C or lower, more preferably 70°C or higher and 80°C or lower, and the melting point of the second melting point component is preferably 145°C or higher and 165°C or lower, more preferably 150°C or higher and 160°C or lower. By adopting this configuration, compared to the case where the resin layer (D) contains only PHBH, the crystals of the second melting point component are not completely dissolved during the melting process and remain to act as crystal nuclei, thereby accelerating the crystallization of PHBH (C). This not only facilitates the formation of the resin layer (D) by extrusion lamination or thermal lamination, but also increases the adhesive strength with the adhesive resin layer (B) formed on a substrate such as paper, as the first melting point component is sufficiently melted.

[0034] PHB can be used instead of highly crystalline PHBH with a 3HH content of less than 6 mol%, and in this case, the PHB acts as a crystal nucleation site, so the same effect can be obtained. Furthermore, PHBH with a 3HH content of less than 6 mol% and PHB may be used in combination.

[0035] The ratio of 3HH to the total of 3HB and 3HH in the highly crystalline PHBH is preferably 5 mol% or less, more preferably 4 mol% or less, and even more preferably 3 mol% or less. Furthermore, the ratio of 3HH to the total of 3HB and 3HH in the low crystalline PHBH is preferably 15 to 40 mol%, and more preferably 15 to 30 mol% or less.

[0036] The amount of the highly crystalline PHBH or PHB blended is not particularly limited, but is preferably 1 to 60% by weight of the PHBH(C) contained in the resin layer (D), more preferably 2 to 50% by weight, and even more preferably 4 to 15% by weight.

[0037] The weight-average molecular weight (hereinafter sometimes referred to as Mw) of PHBH(C) contained in the resin layer (D) is preferably 250,000 to 650,000, more preferably 350,000 to 550,000, and even more preferably 400,000 to 500,000, from the viewpoint of achieving both mechanical properties and processability. If the weight-average molecular weight is 250,000 or more, the mechanical properties of the resin layer (D) are good, and if it is 650,000 or less, it can exhibit a melt viscosity suitable for molding and processing, and the adhesion to the adhesive resin layer (B) formed on a substrate such as paper can be improved.

[0038] In this application, the weight-average molecular weight of PHBH can be determined by gel permeation chromatography (GPC) (Shodex GPC-101, manufactured by Showa Denko Corporation), using a polystyrene gel column (Shodex K-804, manufactured by Showa Denko Corporation) with chloroform as the mobile phase, and expressed as the molecular weight in terms of polystyrene.

[0039] In one embodiment of the present invention, the resin layer (D) can be made by mixing multiple types of PHBH with different weight-average molecular weights.

[0040] The resin layer (D) is preferably a resin layer mainly composed of PHBH(C). Specifically, the PHBH(C) content in the resin layer (D) is preferably 50 to 100% by weight, more preferably 70 to 100% by weight, and even more preferably 80 to 100% by weight. The lower limit may be 90% by weight or more, or 95% by weight or more.

[0041] The resin layer (D) may contain only PHBH, or only PHBH and PHB as resin components, or it may further contain resins other than PHBH and PHB. The resins other than PHBH and PHB are preferably biodegradable resins, specifically poly(3-hydroxybutyrate-co-3-hydroxyvalate) (PHB3HV), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (PHB4HB), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (PHB3HO), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate) (PHB3HOD), poly(3-hydroxybutyrate-co- Examples include poly(3-hydroxyalkanoates) such as 3-hydroxydecanoate (PHB3HD) and poly(3-hydroxybutyrate-co-3-hydroxyvalate-co-3-hydroxyhexanoate) (PHB3HV3HH); aliphatic polyester resins such as polycaprolactone, polybutylene succinate adipate, polybutylene succinate, and polylactic acid; and aliphatic aromatic polyester resins such as polybutylene adipate terephthalate and polybutylene azelate terephthalate. Only one of these resins other than PHBH and PHB may be used, or two or more may be used in combination.

[0042] The resin layer (D) may contain additives that are normally added to resin materials, to the extent that they do not impair the effects of the invention. Examples of such additives include inorganic fillers, colorants such as pigments and dyes, odor absorbers such as activated carbon and zeolites, fragrances such as vanillin and dextrin, plasticizers, antioxidants, weather-resistant modifiers, ultraviolet absorbers, crystal nucleating agents, lubricants, mold release agents, water repellents, antibacterial agents, and sliding properties modifiers. Only one type of these additive may be used, or two or more types may be used in combination. However, the additives are arbitrary components, and the resin layer (D) may not contain these additives. As additives, it is preferable to use lubricants and / or inorganic fillers, from the viewpoint of improving the peelability from the pressure surface such as a cooling roll when laminating the resin layer (D).

[0043] Examples of the lubricant 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, as well as aliphatic amide compounds such as alkylene fatty acid amides such as methylenebisstearic acid amide and methylenebisstearic acid amide, and pentaerythritol.

[0044] The amount of lubricant in the resin layer (D) is preferably 0.1 to 2 parts by weight, and more preferably 0.2 to 1 part by weight, per 100 parts by weight of the total amount of resin components contained in the resin layer (D). By setting the amount to 0.1 parts by weight or more, the peelability improvement effect due to the lubricant can be obtained. If the amount is 2 parts by weight or less, the problem of the lubricant bleeding out during pressing and adhering to the pressing surface such as the cooling roll can be suppressed, and continuous processing for a long period of time can be performed.

[0045] Examples of the inorganic filler include talc, calcium carbonate, mica, silica, clay, kaolin, titanium dioxide, alumina, and zeolite. The average particle size of these inorganic fillers is preferably 0.5 μm or larger.

[0046] The amount of inorganic filler in the resin layer (D) is preferably 0.5 to 5 parts by weight, and more preferably 1 to 3 parts by weight, per 100 parts by weight of the total amount of resin components contained in the resin layer (D). By setting the amount to 0.5 parts by weight or more, the effect of improving release properties due to the inorganic filler can be obtained. If the amount is 5 parts by weight or less, the occurrence of cracks in the resin layer (D) can be suppressed.

[0047] In the laminate according to this embodiment, the thickness of the resin layer (D) is set to a range of 20 μm or more and less than 100 μm. If the thickness is less than 20 μm, the resin may cool too quickly during lamination of the resin layer (D), which may reduce the adhesion between the resin layer (D) and the substrate layer (A) on which the adhesive resin layer (B) is formed. Also, cracks are more likely to occur in the resin layer (D) when the laminate is processed into a molded body. The lower limit of the thickness is preferably 20 μm or more, more preferably 30 μm or more, and particularly preferably 40 μm or more.

[0048] Furthermore, if the thickness of the resin layer (D) exceeds 100 μm, the unevenness of the resin temperature during the formation of the resin layer (D) may increase, potentially leading to uneven thickness and appearance defects due to melt fracture. Additionally, the laminate may become too hard, resulting in molding defects. The upper limit of the thickness is preferably 80 μm or less, and more preferably 60 μm or less.

[0049] [Method for manufacturing laminates] An example of a method for manufacturing the laminate according to this embodiment is described below. The laminate according to this embodiment can be manufactured by forming an adhesive resin layer (B) on at least one side of a base layer (A) by a coating method (first step), and forming a resin layer (D) on the surface of the formed adhesive resin layer (B) (second step).

[0050] In the first step of forming an adhesive resin layer (B) on at least one side of a substrate layer (A), it is preferable to apply an aqueous dispersion such as a solution or aqueous slurry containing the components constituting the adhesive resin layer (B) to one or both sides of the substrate layer (A), and then heat to dry and form a film.

[0051] The method for applying the solution or aqueous dispersion to the substrate is not particularly limited, and any known method capable of forming a resin layer on the substrate can be used as appropriate. Specifically, methods such as spraying, application, slit coater, air knife coater, roll coater, bar coater, comma coater, blade coater, screen printing, and gravure printing can be used. Before applying the solution or aqueous dispersion, the substrate may be subjected to a surface treatment such as the corona treatment described above.

[0052] The drying process after coating can be carried out using known heating methods. Examples include hot air heating, infrared heating, microwave heating, roll heating, and hot plate heating, which can be used individually or in combination of two or more methods.

[0053] Next, a second step is performed to form a resin layer (D) on the surface of the formed adhesive resin layer (B). The method for forming the resin layer (D) may be to apply a solution or aqueous dispersion containing the components constituting the resin layer (D) to the surface of the adhesive resin layer (B), and then heat it to dry and form a film. However, from the viewpoint of adhesion to the adhesive resin layer (B), productivity, and quality that suppresses thermal degradation, it is preferable to form the resin layer (D) on the surface of the adhesive resin layer (B) by an extrusion lamination method or a thermal lamination method.

[0054] As the aforementioned extrusion lamination method, a general extrusion lamination method can be used. Specifically, a molten resin material can be extruded in a film shape from a T-type die, cooled using a cooling roll, and pressed onto the surface of an adhesive resin layer (B). Immediately afterward, the resin material is peeled off from the cooling roll to form a resin layer (D) and produce a laminate.

[0055] As the aforementioned thermal lamination method, a general thermal lamination method can be used. Specifically, first, molten resin material is extruded, for example, from a T-type die, and a film containing the resin material is formed while cooling it using a cooling roll. Then, the obtained film is pressed onto the surface of an adhesive resin layer (B) using a hot roll or the like to produce a molded article.

[0056] For purposes such as improving the adhesion between the resin layer (D) and the substrate layer (A) on which the adhesive resin layer (B) is formed, the surface of the adhesive resin layer (B) may be subjected to corona treatment, flame treatment, ozone treatment, etc.

[0057] The first and second steps described above are preferably performed sequentially and continuously, from the viewpoint of adhesion and processability (balance between melting and crystallization).

[0058] [Molded body] A molded article according to one aspect of this embodiment includes the laminate described above and has a desired size and shape. Since the molded article is formed from a laminate including a resin layer (D) containing PHBH, it is advantageous for various applications.

[0059] The molded body is not particularly limited as long as it includes the laminate, but examples include paper, film, sheet, tube, plate, rod, container (e.g., bottle container), bag, part, etc. From the viewpoint of countermeasures against marine pollution, the molded body is preferably a bag or bottle container.

[0060] The molded body may be the laminate itself, or it may be a laminate that has undergone secondary processing.

[0061] Because the laminate is subjected to secondary processing, the molded body can be suitably used as various packaging container materials such as shopping bags, various types of bags, food and confectionery packaging materials, cups, trays, and cartons (in other words, in various fields such as food, cosmetics, electronics, medical, and pharmaceuticals). Because the laminate contains a resin layer (D) that has high adhesion to the substrate and good heat resistance, it is more preferable as a container for liquids, especially as a container for hot contents such as cups for instant noodles, instant soup, coffee, etc., and trays used for prepared foods, bento boxes, microwaveable foods, etc.

[0062] The aforementioned secondary processing can be carried out using the same methods as conventional resin-laminated paper or coated paper, that is, using various bag-making machines, filling and packaging machines, etc. Processing can also be done using equipment such as paper cup molding machines, die-cutting machines, and box presses. In these processing machines, known techniques can be used for bonding the laminated material, such as heat sealing, impulse sealing, ultrasonic sealing, high-frequency sealing, hot air sealing, and frame sealing.

[0063] The heat sealing temperature of the laminate varies depending on the bonding method, but for example, when using a heated heat seal tester with a sealing bar, the resin temperature is usually set to 180°C or lower, preferably 170°C or lower, and more preferably 160°C or lower. Within this range, it is possible to avoid the resin melting near the sealed area and to ensure an appropriate resin layer thickness and seal strength. Furthermore, when using a heated heat seal tester with a sealing bar, the lower limit of the resin temperature is usually 100°C or higher, preferably 110°C or higher, and more preferably 120°C or higher. Within this range, it is possible to ensure appropriate adhesion at the sealed area.

[0064] The heat sealing pressure of the laminate varies depending on the bonding method, but for example, when using a heated heat sealing tester with a sealing bar, it is usually 0.1 MPa or higher, preferably 0.5 MPa or higher. Within this range, adequate adhesion at the sealed portion can be ensured. Furthermore, the upper limit of the heat sealing pressure when using a heated heat sealing tester with a sealing bar is usually 1.0 MPa or lower, preferably 0.75 MPa or lower. Within this range, thinning of the film thickness at the seal edge can be avoided, and seal strength can be ensured.

[0065] The aforementioned molded body may also be compounded with a molded body made of a different material (for example, fibers, yarn, rope, woven fabric, knitted fabric, nonwoven fabric, paper, film, sheet, tube, board, rod, container, bag, part, foam, etc.) in order to improve its physical properties. These materials are also preferably biodegradable.

[0066] The following sections list preferred embodiments of this disclosure, but the present invention is not limited to these sections. [Item 1] A laminate comprising, in this order, a base layer (A), an adhesive resin layer (B), and a resin layer (D) containing a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (C), wherein the basis weight of the adhesive resin layer (B) is 0.1 g / m². 2 More than 3.0g / m 2 A laminate in which the average content ratio of 3-hydroxyhexanoate in the copolymer (C) is 6 mol% or more, and the thickness of the resin layer (D) is 20 μm or more and less than 100 μm. [Item 2] The laminate according to item 1, wherein the adhesive resin layer (B) contains at least one resin selected from the group consisting of acrylic resin, methacrylic resin, vinyl chloride resin, styrene-acrylic resin, styrene-butadiene resin, styrene-isoprene resin, polycarbonate resin, urea resin, melamine resin, epoxy resin, phenolic resin, urethane resin, diallyl phthalate resin, and imine resin. [Item 3] The copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate has a weight-average molecular weight of 250,000 to 650,000 and an average content ratio of 3-hydroxyhexanoate of 6 to 20 mol%, as described in item 1 or 2. [Item 4] The copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate comprises a first melting point component having a melting point of 60°C or higher and less than 90°C, and a second melting point component having a melting point of 140°C or higher and less than 170°C, as described in any of items 1 to 3. [Item 5] A laminate according to any one of items 1 to 4, wherein the base material layer is paper. [Item 6] A method for manufacturing a laminate described in any of items 1 to 5, A manufacturing method comprising: a first step of forming the adhesive resin layer (B) on at least one side of the substrate layer by a coating method; and a second step of forming the resin layer (D) on the surface of the adhesive resin layer (B) by an extrusion lamination method or a heat lamination method. [Item 7] The manufacturing method according to item 6, wherein the first step and the second step are carried out sequentially and continuously. [Item 8] A molded body containing a laminate as described in any of items 1 to 5. [Examples]

[0067] The present invention will be specifically described below with reference to examples, but the technical scope of the present invention is not limited by these examples.

[0068] [Manufacturing example] (Method for preparing the coating solution) Coating solution 1: An aqueous emulsion containing Zemlac (registered trademark, manufactured by Kaneka Corporation), an acrylic resin with an average particle size of 50 nm and a solid content concentration of 30 wt%, was prepared.

[0069] Coating solution 2: A 30% aqueous solution (10 parts by weight) containing polyethyleneimine resin (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was mixed with an aqueous emulsion (100 parts by weight) containing Zemlac (registered trademark, manufactured by Kaneka Corporation), an acrylic resin with an average particle size of 50 nm and a solid content concentration of 30 wt%.

[0070] (PHBH powder) The PHBH powder used was manufactured in accordance with the method described in International Publication No. 2019-142845. The specific formulation is shown below. PHBH Powder 1: A low-crystalline PHBH powder with a weight-average molecular weight of 590,000 and a 3HH content of 15 mol% relative to the total of 3HB and 3HH in the PHBH. PHBH Powder 2: A highly crystalline PHBH powder with a weight-average molecular weight of 600,000 and a 3HH content of 5.0 mol% relative to the total of 3HB and 3HH in PHBH. PHBH Powder 3: A highly crystalline PHBH powder with a weight-average molecular weight of 310,000 and a 3HH content of 1.5 mol% relative to the total of 3HB and 3HH in PHBH.

[0071] (Method for measuring the melting point of PHBH pellets) Thinly sliced ​​samples of PHBH pellets dried at 60°C (4-10 mg each) were placed in an aluminum pan. Using a differential scanning calorimetry analyzer, the sample was heated from 20°C to 180°C at a rate of 10°C / min under a nitrogen stream to melt it and obtain a crystal melting curve. In the obtained crystal melting curve, the top temperature of the melting peak between 60°C and 90°C was defined as the first melting point, and the top temperature of the melting peak between 140°C and 170°C was defined as the second melting point.

[0072] (Method of manufacturing PHBH pellets) PHBH Pellet 1: PHBH Powder 1 (80 parts by weight) was dry-blended with PHBH Powder 2 (20 parts by weight), behenamide (0.5 parts by weight), and pentaerythritol (1.0 part by weight). The mixture was melt-kneaded using a twin-screw extruder at a set temperature of 150°C and a screw rotation speed of 100 rpm, extruded into strands, solidified by passing through 40°C hot water, and cut into pellets. The weight-average molecular weight of the obtained PHBH pellets was 460,000, the first melting point was 72°C, and the second melting point was 155°C.

[0073] PHBH Pellet 2: PHBH powder 2 (100 parts by weight) was dry-blended with behenamide (0.5 parts by weight) and pentaerythritol (1.0 part by weight). Using a twin-screw extruder, the mixture was melt-kneaded at a set temperature of 150°C and a screw rotation speed of 100 rpm, extruded into strands, solidified by passing through 40°C hot water, and cut into pellets. The weight-average molecular weight of the obtained PHBH pellets was 420,000, and the second melting point was 153°C.

[0074] PHBH pellets 3: PHBH powder 3 (100 parts by weight) was dry-blended with behenamide (0.5 parts by weight) and pentaerythritol (1.0 part by weight). Using a twin-screw extruder, the mixture was melt-kneaded at a set temperature of 150°C and a screw rotation speed of 100 rpm, extruded into strands, solidified by passing through 40°C hot water, and cut into pellets. The weight-average molecular weight of the obtained PHBH pellets was 250,000, and the second melting point was 169°C.

[0075] <Manufacturing of laminates by extrusion lamination method> (Example 1) Weight: 210g / m 2 A sheet of A4-sized base paper was coated with coating solution 1 using a bar coater No. 7. Immediately afterward, it was placed in a hot air oven heated to 100°C for 30 seconds to dry, forming an adhesive resin layer (B) on the paper substrate. The basis weight of the obtained adhesive resin layer (B) was 2.9 g / m². 2 That was the case. Next, the PHBH pellets 1 were fed into a single-screw extruder equipped with a T-type die, taken up by a cooling roll set to 60°C, and formed into a film with a thickness of 40 μm. The paper substrate with the adhesive resin layer (B) obtained above and the PHBH film were sandwiched together so that a heating roll was in contact with the paper side and a cooling roll was in contact with the PHBH film side, and the conditions were adjusted so that the surface temperature of the PHBH film was 170°C, thereby obtaining a laminate containing the paper substrate, the adhesive resin layer (B), and the resin layer (D) in that order.

[0076] (Example 2) A laminate was obtained in the same manner as in Example 1, except that coating solution 1 was applied with a bar coater No. 4. The basis weight of the adhesive resin layer (B) was 1.2 g / m². 2 That was the case.

[0077] (Example 3) A laminate was obtained in the same manner as in Example 1, except that coating liquid 1 was applied with bar coater No. 1. The basis weight of the adhesive resin layer (B) was 0.1 g / m². 2 That was the case.

[0078] (Example 4) A laminate was obtained in the same manner as in Example 1, except that the thickness of the PHBH film was changed to 25 μm.

[0079] (Example 5) A laminate was obtained in the same manner as described in Example 2, except that an adhesive resin layer (B) was formed using coating liquid 2.

[0080] (Comparative Example 1) A laminate containing a paper substrate and a resin layer (D), without the adhesive resin layer (B), was obtained in the same manner as described in Example 1, except that a PHBH film was extruded and laminated onto a base paper that did not have an adhesive resin layer (B).

[0081] (Comparative Example 2) A laminate was obtained in the same manner as in Example 1, except that the thickness of the PHBH film was changed to 10 μm.

[0082] (Comparative Example 3) A laminate was obtained in the same manner as in Example 1, except that coating liquid 1 was applied with a bar coater No. 14. The basis weight of the adhesive resin layer (B) was 6.0 g / m². 2 That was the case.

[0083] (Comparative Example 4) A laminate was obtained in the same manner as described in Example 1, except that PHBH pellet 2 was used instead of PHBH pellet 1.

[0084] (Comparative Example 5) A laminate was obtained in the same manner as described in Example 1, except that PHBH pellet 3 was used instead of PHBH pellet 1.

[0085] [Evaluation Method] The evaluations in the examples and comparative examples were carried out by the following method.

[0086] (Evaluation of lamination strength) The laminate strength test was performed the day after the extrusion lamination. Specifically, a thin cross-cut was made on the resin layer (D) surface of the resulting laminate with a cutter blade, and Nichiban No. CT-17 tape was firmly attached to the cut portion. After that, it was lightly peeled off by hand to create a starting point. Then, it was cut to a width of 15 mm, and the peeled laminate layer and paper were held at a 180° angle using a jig, and the peel strength test was performed. The tensile speed was 200 mm / min. A Shimadzu Autograph EZ-LX (manufactured by Shimadzu Corporation) was used as the peel tester.

[0087] <Rating> ○: 3.0N / 15mm or more △: 2.5N / 15mm or more, less than 3.0N / 15mm ×: 2.0N / less than 15mm If the above evaluation result is ○ or △, it can be said that the lamination strength is sufficient.

[0088] (Evaluation of drying properties) Weight: 210g / m 2 A4-sized base paper was coated under the conditions described in the Examples and Comparative Examples to form an adhesive resin layer (B). After heating in a 100°C hot air oven for 30 seconds, it was removed, and the surface of the adhesive resin layer (B) was observed.

[0089] <Rating> ○: The surface is not wet and a sufficient coating film has formed. △: The surface is slightly damp, but a sufficient coating has formed. ×: Water has accumulated on the surface, indicating that the coating has not formed sufficiently. If the above evaluation result is ○ or △, drying and coating formation in a typical papermaking process are possible.

[0090] (Measurement of basis weight of adhesive resin layer (B)) The paper coated with the adhesive resin layer (B) obtained in the examples and comparative examples was thoroughly dried in a hot air oven heated to 100°C for 10 minutes, and then cured for one week at 25°C and 60% humidity. After that, it was cut into 10cm x 10cm pieces and weighed, and the weight of the adhesive resin layer (B) was taken by subtracting the weight of the base paper from this weight and multiplying by 100.

[0091] [Table 1]

[0092] <Result> Table 1 shows that in each embodiment, the substrate layer (A) and the resin layer (D) containing a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (C) are bonded with sufficient strength via the adhesive resin layer (B), and that the drying properties of the adhesive resin layer (B) after coating are also good. On the other hand, Comparative Examples 1, 2, 4, and 5 showed insufficient adhesion, and Comparative Example 3 showed poor drying properties. Therefore, it can be seen that each of the comparative examples failed to achieve both good adhesion and good drying properties. [Explanation of symbols]

[0093] 1. Laminate 2 Base material layer 3 Adhesive resin layer (B) 4 Resin layer (D)

Claims

1. A laminate comprising, in this order, a base layer (A), an adhesive resin layer (B), and a resin layer (D) containing a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (C), The basis weight of the adhesive resin layer (B) is 0.1 g / m². ２ Above, 3.0g / m ２ It is less than, The copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate comprises a first melting point component having a melting point of 60°C or higher and less than 90°C, and a second melting point component having a melting point of 140°C or higher and less than 170°C. The average content ratio of 3-hydroxyhexanoate in the copolymer (C) is 6 mol% or more. A laminate in which the thickness of the resin layer (D) is 20 μm or more and less than 100 μm.

2. The laminate according to claim 1, wherein the adhesive resin layer (B) contains at least one resin selected from the group consisting of acrylic resin, methacrylic resin, vinyl chloride resin, styrene-acrylic resin, styrene-butadiene resin, styrene-isoprene resin, polycarbonate resin, urea resin, melamine resin, epoxy resin, phenolic resin, urethane resin, diallyl phthalate resin, and imine resin.

3. The laminate according to claim 1 or 2, wherein the copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate has a weight-average molecular weight of 250,000 to 650,000 and an average content ratio of 3-hydroxyhexanoate of 6 to 20 mol%.

4. The laminate according to claim 1 or 2, wherein the base material layer is paper.

5. A method for manufacturing a laminate according to claim 1 or 2, A manufacturing method comprising: a first step of forming the adhesive resin layer (B) on at least one side of the substrate layer by a coating method; and a second step of forming the resin layer (D) on the surface of the adhesive resin layer (B) by an extrusion lamination method or a heat lamination method.

6. The manufacturing method according to claim 5, wherein the first step and the second step are carried out sequentially and continuously.

7. A molded article comprising the laminate described in claim 1 or 2.

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