WO2023068056A1 - Layered body, method for producing same, and molded article - Google Patents

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

LAMINATED PRODUCT, MANUFACTURING METHOD THEREOF, AND MOLDED PRODUCT

The present invention relates to a laminate obtained by laminating a resin layer on at least one side of a substrate layer such as paper, a method for producing the laminate, and a molded article.

In recent years, the environmental problem caused by waste plastic has been highlighted. Among them, marine pollution by waste plastics is serious, and biodegradable plastics that decompose in the natural environment are expected to spread.

Various biodegradable plastics are known, among which 3-hydroxybutyrate (hereinafter sometimes referred to as "3HB") and 3-hydroxyhexanoate (hereinafter sometimes referred to as "3HB") are known. (hereinafter sometimes referred to as "PHBH") is a thermoplastic polyester that is produced and accumulated as an energy storage substance in the cells of many microbial species. Since it is a material that can be biodegraded not only in soil but also in seawater, it is attracting attention as a material that solves the above problems.
Among them, PHBH/paper composite materials, in which PHBH is integrated with a base material such as paper, are of particular social interest because they can be applied to food-contact containers and the like with low environmental load.

Examples of means for integrating PHBH and paper include an extrusion lamination method and a water-based slurry coating method. be However, since PHBH generally has a high melt viscosity and does not easily bite into paper, it was not easy to bond extruded PHBH and paper with sufficient strength. As a result, there has been a problem that the laminate layer is peeled off from the paper in the manufacturing process of a molded cup such as a drinking cup, and the content leaks out when filled.

Although PHBH is not disclosed in Patent Document 1, 10 g of a polycaprolactone dispersion or emulsion is placed on the paper for the purpose of improving the penetration of the biodegradable resin into the paper and improving the laminate strength. 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 layer) of /m ² (dry weight of layer) and drying.

JP-A-6-293113

According to the method ^of Patent Document 1, the adhesion between the paper and the resin layer tends to be improved. Drying takes a long time and productivity is not high, and there are problems such as deterioration of the paper base material due to the drying, and warping of the laminate due to excessive drying of the paper.

In order to facilitate drying, there is a method of reducing the basis weight of the adhesive layer to less than 10 g/m ² , but in that case there is a problem that the adhesiveness between the paper substrate and the resin layer becomes insufficient. .

In view of the above situation, the present invention provides a laminate comprising a substrate layer, an adhesive layer, and a resin layer containing a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate in this order, Another object of the present invention is to provide a laminate having good drying property when forming an adhesive layer and having high adhesive strength between a substrate layer and a resin layer.

As a result of intensive studies to solve the above problems, the present inventors have found that a copolymer of a substrate layer (A), an adhesive resin layer (B), 3-hydroxybutyrate and 3-hydroxyhexanoate In a laminate including a resin layer (D) including coalescence in this order, the thickness of the resin layer (D) is set within a specific range while the basis weight of the adhesive resin layer (B) is sufficiently reduced. The present inventors have found that the above problems can be solved by the method, and have completed the present invention.

That is, the present invention comprises a substrate layer (A), an adhesive resin layer (B), and a resin layer (D) containing a copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate. in this order, wherein the basis weight of the adhesive resin layer (B) is 0.1 g/m ² or more and less than 3.0 g/m ² , and The laminate has an average content ratio of 3-hydroxyhexanoate of 6 mol % or more, and a thickness of the resin layer (D) of 20 μm or more and less than 100 μm.
The present invention also provides a method for manufacturing the laminate,
A first step of forming the adhesive resin layer (B) on at least one side of the base material layer by a coating method, and extrusion laminating the resin layer (D) on the surface of the adhesive resin layer (B) It also relates to a manufacturing method, including a second step of forming by a method or a thermal lamination method.

According to the present invention, a laminate comprising a substrate layer, an adhesive layer, and a resin layer containing a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate in this order, the adhesive layer It is possible to provide a laminate having good drying property when forming and having high adhesive strength between the base material layer and the resin layer. Use of the laminate can improve production efficiency and quality of molded articles.

It is a schematic diagram which shows the laminated structure of the laminated body which concerns on this embodiment.

Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

[Laminate]
A laminate according to one embodiment of the present invention comprises an adhesive resin layer (B) and a copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate ( and a resin layer (D) containing C). As shown in FIG. 1, in the laminate 1, the substrate 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 They are stacked in this order.

The adhesive resin layer (B) may be directly laminated on the base material layer (A), and the adhesive resin layer (B) and the base material layer (B) may be laminated as long as the adhesiveness is not impaired. A) may further include another resin layer as an intermediate layer.

Only one side of the substrate layer (A) may have the adhesive resin layer (B) and the resin layer (D), or both sides of the substrate layer (A) may have the adhesive resin layer (B) and a resin layer (D).

When the base material layer (A) has the adhesive resin layer (B) and the resin layer (D) only on one side, another layer is not formed on the other side, and the base layer (A) is laminated. It may be the outermost layer exposed on the surface of the body, or another layer may be laminated for the purpose of imparting water resistance, gloss, or adhesiveness.

When both surfaces of the substrate layer (A) have an adhesive resin layer (B) and a resin layer (D), respectively, the adhesive resin layer (B) on the front side and the adhesive resin layer (B) on the back side are formed. The materials to be used, the basis weight, and the thickness may be the same or different. The same applies to the resin layer (D) on the front side and the resin layer (D) on the back side. The basis weight (g/m ² ) in the present application refers to the dry weight (solid content) of the layer.

[Base layer (A)]
The material constituting the base layer (A) is not particularly limited, but is preferably biodegradable. Examples include paper (mainly cellulose), cellophane, cellulose ester; polyvinyl alcohol, polyamino acid, polyglycol. acid, pullulan, or those obtained by vapor-depositing inorganic substances such as aluminum and silica on these base materials; Among them, paper is preferable because it has excellent heat resistance and is inexpensive.

The type of paper is not particularly limited, and can be appropriately selected according to the application of the laminate. If necessary, the paper may be added with water-resistant agents, water-repellent agents, inorganic substances, etc., and may be subjected to surface treatments such as oxygen barrier layer coating and water vapor barrier coating.

Further, the base material layer (A) may be subjected to surface treatment such as corona treatment, ozone treatment, plasma treatment, flame treatment, anchor coat treatment, oxygen barrier layer coating, and water vapor barrier coating. These surface treatments may be performed singly or in combination with a plurality of surface treatments.

[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, but resins commonly used in the coated paper field or the resin film field can be preferably used. It is desirable that at least one or more resins having a high affinity for substrates such as paper and PHBH are contained. resins, styrene-butadiene-based resins, styrene-isoprene-based resins, polycarbonate-based resins, urea resins, melamine-based resins, epoxy-based resins, phenol-based resins, urethane-based resins, diallyl phthalate-based resins, imine-based resins, etc. . These resins can be used singly, or two or more resins can be mixed in an arbitrary ratio and used.

The resin contained in the adhesive resin layer (B) may be either water-soluble or soluble in an organic solvent. When using water insoluble resins, other additives may be added to improve dispersibility in water and coatability. When coating an aqueous emulsion, aqueous slurry, or water-soluble resin, the solid content concentration of the resin is not particularly limited. is more preferable, and 50% by weight or more is even more preferable. Moreover, from the viewpoint of avoiding sedimentation of the dispersed resin and achieving good coatability, the solid content concentration is preferably 60% by weight or less.

In the laminate according to this embodiment, the basis weight of the adhesive resin layer (B) is adjusted to a 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 to the resin layer (D) may deteriorate. Conversely, if it exceeds 3.0 g/m ² , a large amount of heat is required for drying, which increases the load on the equipment, and, for example, blocking during winding of the raw fabric may become a problem due to poor drying.
The basis weight is more preferably 0.5 g/m ² or more and 2.5 g/m ² or less, and further preferably 1.0 g/m ² or more and 2.0 g/m ² or less.

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

By changing the content ratio of repeating units, PHBH changes the melting point and crystallinity. As a result, physical properties such as Young's modulus and heat resistance can be easily adjusted. Since it is possible to impart physical properties, it is an industrially particularly useful plastic.

A specific method for producing PHBH is described, for example, in International Publication No. 2010/013483. Commercially available products of PHBH include Kaneka Corporation "Kaneka Biodegradable Polymer Green Planet" (registered trademark).

The average content ratio of each constituent monomer in PHBH (C) is preferably 3HB/3HH = 94 to 80/6 to 20 (mol%/mol%), and 3HB/3HH = 90 to 82/10 to 18. (mol%/mol%) is more preferred. When the average content ratio of 3HH in PHBH (C) is 6 mol% or more, the adhesiveness with the adhesive resin layer (B) formed on a substrate such as paper can be improved. Further, when the average content ratio of 3HH is 20 mol % or less, the crystallization speed of PHBH does not become too slow, and production is relatively easy.

The average content ratio of each constituent monomer in PHBH(C) means the molar ratio of 3HB and 3HH contained in PHBH(C). When the 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, each component contained in the entire mixture It refers to the molar ratio of monomers. The average content ratio of the constituent monomers 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, or by NMR measurement.

As described above, the PHBH (C) contained in the resin layer (D) may contain at least two types of PHBH having different content ratios of constituent monomers, and in addition to at least one type of PHBH, PHB ( 3-Hydroxybutyrate homopolymer) may be further included.

When at least two types of PHBH are included, a highly crystalline and high melting point PHBH having a 3HH content of less than 6 mol% and a low crystalline and low melting PHBH having a 3HH content of 15 mol% or more is preferably included.

In particular, the PHBH (C) contained in the resin layer (D) includes a first melting point component (low crystallinity component) having a melting point of 60° C. or more and less than 90° C. and a melting point of 140° C. or more and less than 170° C. It is preferred to include at least two PHBH components, some second melting point components (highly crystalline components). 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, and 150° C. or higher. , 160° C. or lower. With such a configuration, the crystals of the second melting point component are not completely dissolved and crystal nuclei are left during melt processing, compared to the case where the resin layer (D) contains only PHBH alone. By acting as, the crystallization of PHBH (C) can be accelerated, and not only the formation of the resin layer (D) by the extrusion lamination method or the heat lamination method is facilitated, but also the first melting point component is sufficiently melted. By doing so, the adhesive strength with the adhesive resin layer (B) formed on the substrate such as paper can be increased.

PHB can be used in place of highly crystalline PHBH with a 3HH content of less than 6 mol%, and even in that case, the PHB acts as a crystal nucleus, so that similar effects can be obtained. PHBH and PHB having a 3HH content of less than 6 mol % may be used together.

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. The ratio of 3HH to the sum of 3HB and 3HH in the low-crystalline PHBH is preferably 15 to 40 mol%, more preferably 15 to 30 mol% or less.

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

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 from the viewpoint of achieving both mechanical properties and workability. 350,000 to 550,000 is more preferable, and 400,000 to 500,000 is even more preferable. When the weight average molecular weight is 250,000 or more, the mechanical properties of the resin layer (D) are good, and when it is 650,000 or less, the melt viscosity suitable for molding can be exhibited, and the base material such as paper can be used. Adhesion with the adhesive resin layer (B) formed thereon can be improved.

In the present application, the weight-average molecular weight of PHBH was determined by gel permeation chromatography (GPC) (“Shodex GPC-101” manufactured by Showa Denko KK) using polystyrene gel (“Shodex K-804” manufactured by Showa Denko KK) as a column. It can be obtained as a molecular weight when converted to polystyrene using chloroform as a mobile phase.

In one embodiment of the present invention, a plurality of types of PHBH having different weight average molecular weights can be mixed and used for the resin layer (D).

The resin layer (D) is preferably a resin layer containing PHBH (C) as a main component. Specifically, the content of PHBH (C) in the resin layer (D) is preferably 50 to 100% by weight, more preferably 70 to 100% by weight, even more preferably 80 to 100% by weight. The lower limit may be 90% by weight or more, or may be 95% by weight or more.

The resin layer (D) may contain only PHBH or only PHBH and PHB as resin components, or may further contain resins other than PHBH and PHB. Resins other than PHBH and PHB are preferably biodegradable resins. Specifically, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB3HV), poly(3-hydroxybutyrate), late-co-4-hydroxybutyrate) (PHB4HB), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (PHB3HO), poly(3-hydroxybutyrate-co-3-hydroxyoctadeca noate) (PHB3HOD), poly(3-hydroxybutyrate-co-3-hydroxydecanoate) (PHB3HD), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexa Noate) (PHB3HV3HH) and other poly(3-hydroxyalkanoates); polycaprolactone, polybutylene succinate adipate, polybutylene succinate, polylactic acid and other aliphatic polyester resins; Aliphatic-aromatic polyester-based resins such as late terephthalate and the like are included. These resins other than PHBH and PHB may be used alone or in combination of two or more.

The resin layer (D) may contain additives normally added to resin materials within a range that does not impair the effects of the invention. Such additives include, for example, inorganic fillers, pigments, colorants such as dyes, odor absorbers such as activated carbon and zeolite, fragrances such as vanillin and dextrin, plasticizers, antioxidants, antioxidants, weather resistant A property improver, an ultraviolet absorber, a crystal nucleating agent, a lubricant, a release agent, a water repellent, an antibacterial agent, a slidability improver, and the like. As these additives, only one type may be used, or two or more types may be used in combination. However, the additive is an optional component, and the resin layer (D) may not contain these additives. As the additive, it is preferable to use a lubricant and/or an inorganic filler from the viewpoint of improving the releasability from a pressing surface such as a cooling roll when laminating the resin layer (D).

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; Examples include aliphatic amide compounds such as alkylene fatty acid amides such as bis-stearic acid amide, and pentaerythritol.

The amount of the lubricant in the resin layer (D) is preferably 0.1 to 2 parts by weight, preferably 0.2 to 2 parts by weight, per 100 parts by weight of the total amount of the resin components contained in the resin layer (D). 1 part by weight is more preferred. By setting the blending amount to 0.1 part by weight or more, it is possible to obtain the effect of improving the peelability by blending the lubricant. When the blending amount is 2 parts by weight or less, it is possible to suppress the problem that the lubricant bleeds and adheres to the pressing surface such as the cooling roll during pressing, and it is possible to carry out continuous processing for a long time.

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

The amount of the inorganic filler compounded in the resin layer (D) is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the total amount of the resin components contained in the resin layer (D), and 1 to 5 parts by weight. 3 parts by weight is more preferred. By setting the blending amount to 0.5 parts by weight or more, it is possible to obtain the effect of improving the peelability due to the blending of the inorganic filler. When the blending amount is 5 parts by weight or less, cracking in the resin layer (D) can be suppressed.

In the laminate according to this embodiment, the thickness of the resin layer (D) is set within the range of 20 µm or more and less than 100 µm. If the thickness is less than 20 µm, the resin is cooled too quickly during lamination of the resin layer (D), and the adhesiveness to the substrate layer (A) on which the adhesive resin layer (B) is formed may decrease. be. In addition, cracks are likely to occur in the resin layer (D) when processing the laminate 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.

Further, if the thickness of the resin layer (D) exceeds 100 μm, the unevenness of the resin temperature increases during the formation of the resin layer (D), which may cause thickness unevenness and poor appearance due to melt fracture. In addition, the laminate may become too hard, resulting in poor molding. The upper limit of the thickness is preferably 80 µm or less, more preferably 60 µm or less.

[Method for manufacturing laminate]
An example of a method for manufacturing the laminate according to this embodiment will be described below.
In the laminate according to the present embodiment, the adhesive resin layer (B) is formed on at least one side of the substrate layer (A) by a coating method (first step), and the formed adhesive resin layer (B) is It can be produced by forming a resin layer (D) on the surface (second step).

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

The method of 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, a spraying method, a spraying method, a slit coater method, an air knife coater method, a roll coater method, a bar coater method, a comma coater method, a blade coater method, a screen printing method, a gravure printing method, or the like 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.

The drying treatment after application can be performed using a known heating method. Examples thereof include hot air heating, infrared heating, microwave heating, roll heating, and hot plate heating, and these can be used alone or in combination of two or more.

Next, the second step of forming the resin layer (D) on the surface of the formed adhesive resin layer (B) is performed. The method of forming the resin layer (D) comprises applying a solution or aqueous dispersion containing components constituting the resin layer (D) to the surface of the adhesive resin layer (B), heating to dry and form a film. may be However, from the viewpoint of adhesion with the adhesive resin layer (B), productivity, or the quality of suppressing thermal deterioration, the surface of the adhesive resin layer (B) is subjected to an extrusion lamination method or a heat lamination method. It is preferable to form the resin layer (D) on

A general extrusion lamination method can be used as the extrusion lamination method. Specifically, the molten resin material is extruded into a film form from a T-shaped die, cooled using a cooling roll and pressed against the surface of the adhesive resin layer (B), and immediately after that, the resin is removed from the cooling roll. By peeling off the material, a resin layer (D) can be formed and a laminate can be produced.

A general heat lamination method can be used as the heat lamination method. Specifically, first, a melted resin material is extruded through, for example, a T-shaped die, and cooled using a cooling roll to form a film containing the resin material. Then, the obtained film is pressure-bonded to the surface of the adhesive resin layer (B) using a hot roll or the like to produce a molded article.

For the purpose of improving the adhesion between the resin layer (D) and the substrate layer (A) on which the adhesive resin layer (B) is formed, a corona is applied to the surface of the adhesive resin layer (B). Treatment, flame treatment, ozone treatment, etc. may be performed.

From the viewpoint of adhesiveness and processability (balance between melting and crystallization), it is preferable to perform the first step and the second step in succession.

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

The molded article is not particularly limited as long as it contains the laminate, and examples thereof include paper, film, sheet, tube, plate, rod, container (eg, bottle container), bag, and parts. The molded article is preferably a bag or a bottle container from the viewpoint of marine pollution countermeasures.

The molded body may be the laminate itself, or may be the laminate obtained by secondary processing.

By secondary processing of the laminate, the molded article can be used as various packaging container materials such as shopping bags, various bag making, food and confectionery packaging materials, cups, trays, cartons (in other words, food, (in various fields such as cosmetics, electronics, medicine, pharmaceuticals, etc.). Since the laminate includes a resin layer (D) having high adhesiveness to a substrate and good heat resistance, it can be used as a container for holding a liquid, especially a food cup such as instant noodles, instant soup, coffee, or a side dish. , boxed lunches, trays for microwave foods, and the like, which are more preferable as containers for containing warm contents.

The secondary processing can be performed in the same manner as conventional resin-laminated paper or coated paper, that is, using various bag-making machines, filling and packaging machines, and the like. Moreover, it can also be processed using devices such as a paper cup molding machine, a punching machine, and a box machine. In these processing machines, known techniques can be used for bonding the laminate, such as heat sealing, impulse sealing, ultrasonic sealing, high frequency sealing, hot air sealing, frame sealing, and the like. can be used.

The heat-sealing temperature of the laminate varies depending on the adhesion method. ℃ or less. Within the above range, it is possible to avoid leaching out of the resin in the vicinity of the sealing portion, and to secure an appropriate film thickness of the resin layer and secure the sealing strength. The lower limit of the resin temperature when using a heat seal tester having a seal bar is usually 100° C. or higher, preferably 110° C. or higher, and more preferably 120° C. or higher. Within the above range, it is possible to ensure proper adhesion at the seal portion.

The heat-sealing pressure of the laminate varies depending on the bonding method, but is usually 0.1 MPa or more, preferably 0.5 MPa or more when using a heat-type heat-sealing tester having a seal bar, for example. Within the above range, it is possible to ensure proper adhesion at the seal portion. Moreover, the upper limit of the heat seal pressure when using a heat-type heat seal tester having a seal bar is usually 1.0 MPa or less, preferably 0.75 MPa or less. When it is within the above range, it is possible to avoid thinning of the film thickness at the end of the seal and secure the seal strength.

In order to improve the physical properties of the molded article, the molded article is made of a material different from that of the molded article (e.g., fiber, thread, rope, woven fabric, knitted fabric, non-woven fabric, paper, film, sheet, tube, board, etc.). , rods, containers, bags, parts, foams, etc.). These materials are also preferably biodegradable.

The following items list preferred embodiments in the present disclosure, but the present invention is not limited to the following items.
[Item 1]
Including a substrate layer (A), an adhesive resin layer (B), and a resin layer (D) containing a copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate in this order. In the laminate, the basis weight of the adhesive resin layer (B) is 0.1 g/m ² or more and less than 3.0 g/m ² , and 3-hydroxyhexano in the copolymer (C) A laminate in which the average content ratio of ate 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 adhesive resin layer (B) includes acrylic resin, methacrylic resin, vinyl chloride resin, styrene-acrylic resin, styrene-butadiene resin, styrene-isoprene resin, polycarbonate resin, urea resin, melamine resin. The laminate according to item 1, containing at least one resin selected from the group consisting of resins, epoxy resins, phenol resins, urethane resins, diallyl phthalate resins, and imine resins.
[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. %, the laminate according to 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 more and less than 90° C. and a melting point of 140° C. or more and less than 170° C. A laminate according to any one of items 1 to 3, comprising a certain second melting point component.
[Item 5]
The laminate according to any one of items 1 to 4, wherein the base material layer is paper.
[Item 6]
A method for producing a laminate according to any one of items 1 to 5,
A first step of forming the adhesive resin layer (B) on at least one side of the base material layer by a coating method, and extrusion laminating the resin layer (D) on the surface of the adhesive resin layer (B) A manufacturing method including a second step of forming by a method or a thermal lamination method.
[Item 7]
7. The manufacturing method according to item 6, wherein the first step and the second step are sequentially and continuously performed.
[Item 8]
A molded article comprising the laminate according to any one of Items 1 to 5.

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.

[Manufacturing example]
(Method for preparing coating liquid)
Coating liquid 1: A water-based emulsion containing an acrylic resin having an average particle diameter of 50 nm and a solid content concentration of 30 wt % and Zemurak (registered trademark, manufactured by Kaneka Corporation) was prepared.

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

(PHBH powder)
As the PHBH powder, one manufactured according to the method described in International Publication No. 2019-142845 was used. A specific formulation is shown below.
PHBH powder 1: Low crystalline PHBH powder having a weight average molecular weight of 590,000 and a ratio of 3HH to the total of 3HB and 3HH in PHBH being 15 mol% Highly crystalline PHBH powder in which the ratio of 3HH to the total is 5.0 mol% PHBH powder 3: Weight average molecular weight 310,000, highly crystalline in which the ratio of 3HH to the total of 3HB and 3HH in PHBH is 1.5 mol% PHBH Powder

(Method for measuring the melting point of PHBH pellets)
PHBH pellets dried at 60° C. and thinly sliced (4-10 mg) are filled in an aluminum pan and heated from 20° C. to 180° C. at a rate of 10° C./min using a differential scanning calorimeter under a nitrogen stream. to obtain a crystalline melting curve. In the obtained crystalline melting curve, the top temperature of the melting peak at 60°C or higher and lower than 90°C was taken as the first melting point, and the top temperature of the melting peak at 140°C or higher and lower than 170°C was taken as the second melting point.

(Method for producing PHBH pellets)
PHBH pellet 1: PHBH powder 1 (80 parts by weight), PHBH powder 2 (20 parts by weight), behenic acid amide (0.5 parts by weight), and pentaerythritol (1.0 parts by weight) were dry blended. 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, passed through hot water at 40° C. to solidify, and cut into pellets. The PHBH pellets thus obtained had a weight average molecular weight of 460,000, a first melting point of 72°C and a second melting point of 155°C.

PHBH Pellets 2: With respect to the PHBH powder 2 (100 parts by weight), behenic acid amide (0.5 parts by weight) and pentaerythritol (1.0 parts by weight) are dry blended, and set using a twin-screw extruder. The mixture was melt-kneaded at a temperature of 150° C. and a screw rotation speed of 100 rpm, extruded into strands, passed through hot water at 40° C. to solidify, and cut into pellets. The PHBH pellets thus obtained had a weight average molecular weight of 420,000 and a second melting point of 153°C.

PHBH pellet 3: The PHBH powder 3 (100 parts by weight), behenic acid amide (0.5 parts by weight) and pentaerythritol (1.0 parts by weight) are dry blended, and set using a twin-screw extruder. The mixture was melt-kneaded at a temperature of 150° C. and a screw rotation speed of 100 rpm, extruded into strands, passed through hot water at 40° C. to solidify, and cut into pellets. The PHBH pellets thus obtained had a weight average molecular weight of 250,000 and a second melting point of 169°C.

<Production of laminate by extrusion lamination method>
(Example 1)
Coating liquid 1 was applied to a base paper of A4 size having a basis weight of 210 g/m ² with a bar coater No. 1. 7, and immediately thereafter placed in a hot air oven heated to 100° C. for 30 seconds to dry to form an adhesive resin layer (B) on the paper substrate. The basis weight of the obtained adhesive resin layer (B) was 2.9 g/m ² .
Subsequently, the PHBH pellets 1 were put into a single-screw extruder equipped with a T-shaped die, taken up by a cooling roll set at 60° C., and formed into a film having a thickness of 40 μm. The paper substrate with the adhesive resin layer (B) obtained above and the PHBH film were sandwiched so that the heating roll was in contact with the paper surface side and the cooling roll was in contact with the PHBH film side, and the surface temperature of the PHBH film was 170 ° C. The conditions were adjusted so as to obtain a laminate containing the paper substrate, the adhesive resin layer (B), and the resin layer (D) in this order.

(Example 2)
Bar coater No. 1 was applied to coating liquid 1. A laminate was obtained in the same manner as described in Example 1, except for coating with No. 4. The basis weight of the adhesive resin layer (B) was 1.2 g/m ² .

(Example 3)
Bar coater No. 1 was applied to coating liquid 1. A laminate was obtained in the same manner as described in Example 1, except for coating with No. 1. The basis weight of the adhesive resin layer (B) was 0.1 g/m ² .

(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.

(Example 5)
A laminate was obtained in the same manner as in Example 2, except that coating liquid 2 was used to form the adhesive resin layer (B).

(Comparative example 1)
A paper substrate without the adhesive resin layer (B) was prepared in the same manner as in Example 1 except that the PHBH film was extrusion-laminated on the base paper without the adhesive resin layer (B). and a laminate containing the resin layer (D).

(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.

(Comparative Example 3)
Bar coater No. 1 was applied to coating liquid 1. A laminate was obtained in the same manner as described in Example 1, except for coating with No. 14. The basis weight of the adhesive resin layer (B) was 6.0 g/m ² .

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

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

〔Evaluation methods〕
Evaluations in Examples and Comparative Examples were performed by the following methods.

(Evaluation of lamination strength)
The lamination strength test was performed on the day after extrusion lamination was performed. Specifically, the surface of the resin layer (D) of the obtained laminate was thinly cross-cut with a cutter blade, and Nichiban No. 2 was applied to the cut portion. After the CT-17 tape was firmly attached, it was lightly peeled off by hand to provide a trigger. After that, the sheet was cut to a width of 15 mm, and the peeled laminate layer and the paper were each held at an angle of 180° with a jig, and a peel strength test was performed. The tensile speed was 200 mm/min. As a peel tester, Shimadzu Autograph EZ-LX (manufactured by Shimadzu Corporation) was used.

<Evaluation>
◯: 3.0 N/15 mm or more Δ: 2.5 N/15 mm or more and less than 3.0 N/15 mm ×: Less than 2.0 N/15 mm If the above evaluation result is ◯ or Δ, it can be said that there is sufficient lamination strength.

(Evaluation of dryness)
A4 size base paper with a basis weight of 210 g/m ² is coated under the conditions described in Examples and Comparative Examples to form an adhesive resin layer (B), and then heated in a hot air oven at 100 ° C. for 30 seconds. After that, it was taken out, and the state of the surface of the adhesive resin layer (B) was observed.

<Evaluation>
○: The surface is not wet and the coating film is sufficiently formed △: The surface is slightly damp, but the coating film is sufficiently formed ×: A puddle is formed on the surface, and the coating film is formed Insufficient formation If the above evaluation result is ◯ or Δ, drying and coating film formation in a general papermaking process are possible.

(Measurement of basis weight of adhesive resin layer (B))
The paper with the adhesive resin layer (B) obtained in Examples and Comparative Examples was sufficiently dried for 10 minutes in a hot air oven heated to 100°C, and then aged for 1 week at 25°C and 60% humidity. . After that, a piece of 10 cm×10 cm was cut out to measure the weight, and the value obtained by subtracting the weight of the base paper from the weight value and multiplying by 100 was used as the basis weight of the adhesive resin layer (B).

<Results>
From Table 1, in each example, the substrate layer (A) and the resin layer (D) containing the copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate are combined into an adhesive resin layer (B ), and the adhesive resin layer (B) is dried well after coating.
On the other hand, in Comparative Examples 1, 2, 4 and 5, the adhesiveness was insufficient, and in Comparative Example 3, the drying property was poor. I understand.

1 Laminate 2 Base Material Layer 3 Adhesive Resin Layer (B)
4 resin layer (D)

Claims (8)

1. Including a substrate layer (A), an adhesive resin layer (B), and a resin layer (D) containing a copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate in this order. In the laminate, the basis weight of the adhesive resin layer (B) is 0.1 g/m ² or more and less than 3.0 g/m ² , and 3-hydroxyhexano in the copolymer (C) A laminate in which the average content ratio of ate is 6 mol % or more, and the thickness of the resin layer (D) is 20 μm or more and less than 100 μm.
2. The adhesive resin layer (B) includes acrylic resin, methacrylic resin, vinyl chloride resin, styrene-acrylic resin, styrene-butadiene resin, styrene-isoprene resin, polycarbonate resin, urea resin, melamine resin. The laminate according to claim 1, comprising at least one resin selected from the group consisting of resins, epoxy resins, phenol resins, urethane resins, diallyl phthalate resins, and imine resins.
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. %, the laminate according to claim 1 or 2.
4. The copolymer (C) of 3-hydroxybutyrate and 3-hydroxyhexanoate comprises a first melting point component having a melting point of 60° C. or more and less than 90° C. and a melting point of 140° C. or more and less than 170° C. 3. Laminate according to claim 1 or 2, comprising a certain second melting point component.
5. The laminate according to claim 1 or 2, wherein the base material layer is paper.
6. A method for manufacturing the laminate according to claim 1 or 2,
   A first step of forming the adhesive resin layer (B) on at least one side of the base material layer by a coating method, and extrusion laminating the resin layer (D) on the surface of the adhesive resin layer (B) A manufacturing method including a second step of forming by a method or a thermal lamination method.
7. The manufacturing method according to claim 6, wherein the first step and the second step are sequentially and continuously performed.
8. A molded article comprising the laminate according to claim 1 or 2.
   

Images