Laminate, method for manufacturing same, and aqueous dispersion

Abstract

Provided is a laminate including a resin layer (B) provided on at least one surface of a substrate layer (A). The resin layer (B) contains a poly(3-hydroxyalkanoate) resin (b1) and a non-water-soluble resin (b2) other than the resin (b1), and the resin (b1) has at least one peak top temperature (Tma) in a range of 100-150°C on a crystal melting curve obtained by means of differential scanning calorimetric analysis.

Description

Laminate, method for manufacturing the same, and aqueous dispersion

[0001] The present invention relates to a laminate comprising a base material layer and a resin layer, a method for producing the same, and an aqueous dispersion.

[0002] In recent years, the problem of marine pollution caused by the disposal of plastic packaging materials has come into focus, and packaging materials made from paper, which have a lower environmental impact, are attracting attention.

[0003] Typically, paper used as packaging material is laminated with resin to provide properties such as water resistance, oil resistance, and heat sealability. It is preferable to use a biodegradable resin for this lamination, so as not to impair the biodegradability of the paper.

[0004] Among biodegradable resins, poly(3-hydroxyalkanoate) resins are thermoplastic polyesters that are produced and stored as energy storage substances within the cells of many microbial species. They are attracting attention as materials that can biodegrade not only in soil but also in seawater.

[0005] Laminates formed by laminating such poly(3-hydroxyalkanoate) resins onto a paper substrate are extremely promising from an environmental protection standpoint. Patent documents 1 to 4 disclose such laminates.

[0006] Patent Document 1 discloses that, in order to improve the adhesive strength of the resin layer by heat sealing when secondary processing of a laminate, a resin layer containing a poly(3-hydroxybutyrate) resin has peak top temperatures in the range of 100 to 150°C and 150 to 170°C in the crystal melting curve. Furthermore, as a method for forming the resin layer, it is disclosed that an aqueous coating solution containing the poly(3-hydroxybutyrate) resin is applied to a substrate and then heated at 130 to 170°C. In the examples, it is also described that methylcellulose is blended into the aqueous coating solution.

[0007] Patent Document 2 discloses the formulation of a specific amount of adhesive into a resin layer containing poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) for the purpose of reducing coating defects in the coating layer. It states that fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, and partially saponified ethylene-vinyl acetate copolymer are preferred as the adhesive. It also states that the resin layer should be dried at 160°C.

[0008] Patent Document 3 describes adding a specific amount of polyvinyl alcohol with a degree of saponification of 70 to 95 mol% to a resin layer containing poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) for the purpose of improving the strength of the resin layer.

[0009] Patent Document 4 discloses that when coating a substrate such as paper with an aqueous emulsion containing a polyhydroxybutyric acid / polyhydroxyvaleric acid copolymer, a carboxylate-based dispersant or polyvinyl alcohol is added to the aqueous emulsion for the purpose of improving its dispersibility.

[0010] International Publication No. 2022 / 059592, International Publication No. 2021 / 256831, International Publication No. 2024 / 043201, Japanese Patent Publication No. Hei 2-222421

[0011] In the laminate described in Patent Document 1, a resin layer exhibiting the aforementioned melting characteristics is formed by applying an aqueous coating liquid to a substrate and then heating it at a high temperature of 130 to 170°C. However, because it is heated at a high temperature, the poly(3-hydroxybutyrate) resin melts, and it takes time for the resin to solidify afterward. If the laminate is wound into a roll before the resin has fully solidified, blocking may occur (i.e., the substrate layer and the resin layer adhere to each other, or the resin layers adhere to each other), which can cause problems when unwinding it from the roll.

[0012] Lowering the heating temperature after applying the aqueous coating solution can suppress this blocking, but because the resin is not melted, the adhesion strength between the substrate and the resin layer becomes insufficient, leading to the problem of the resin layer easily peeling off.

[0013] Furthermore, the aforementioned blocking problem is more likely to occur when the laminate is rolled up and stored for a long time, or when it is exposed to high temperatures during transportation.

[0014] In the laminates described in Patent Documents 2 to 4, a water-soluble adhesive such as polyvinyl alcohol is incorporated into the resin layer. Therefore, under conditions where the laminate comes into contact with water, the adhesive dissolves in the water, leading to problems such as delamination of the resin layer and a decrease in adhesion strength and mechanical properties. In particular, such problems become more pronounced when the laminate is used as a container for food and beverages containing water, and thus improvement was necessary.

[0015] In view of the above, the present invention aims to provide a laminate comprising a base layer and a resin layer containing a poly(3-hydroxyalkanoate) resin, wherein blocking is suppressed and the water resistance of the resin layer is improved, a method for manufacturing the same, and an aqueous dispersion usable in the manufacture of the laminate.

[0016] As a result of diligent research to solve the above problems, the inventors of the present invention have found that the above problems can be solved by using a poly(3-hydroxyalkanoate) resin that exhibits specific melting characteristics in a laminate comprising a base layer and a resin layer containing a poly(3-hydroxyalkanoate) resin, and by blending a water-insoluble resin into the resin layer, thereby completing the present invention.

[0017] In other words, the present invention relates to a laminate comprising a base layer (A) and a resin layer (B) provided on at least one surface of the base layer, wherein the resin layer (B) contains a poly(3-hydroxyalkanoate) resin (b1) and a water-insoluble resin other than resin (b2), and the poly(3-hydroxyalkanoate) resin (b1) has at least one peak-top temperature (Tma) in the range of 100 to 150°C in the crystal melting curve obtained by differential scanning calorimetry. The present invention also relates to a molded article comprising the laminate. Furthermore, the present invention relates to a method for manufacturing a laminate, comprising the steps of applying an aqueous dispersion containing a poly(3-hydroxyalkanoate) resin (b1) having at least one peak top temperature (Tma) in the range of 100 to 150°C in a crystal melting curve determined by differential scanning calorimetry, and a water-insoluble resin (b2) other than the resin (b1), to at least one surface of a base layer (A), and heating and drying at 95 to 120°C to form a resin layer (B) on the base layer (A). Furthermore, the present invention also relates to an aqueous dispersion comprising a poly(3-hydroxyalkanoate) resin (b1) and a water-insoluble resin (b2) other than the resin (b1) dispersed in water, wherein the poly(3-hydroxyalkanoate) resin (b1) has at least one peak top temperature (Tma) in the range of 100 to 150°C in a crystal melting curve determined by differential scanning calorimetry.

[0018] According to the present invention, it is possible to provide a laminate comprising a base layer and a resin layer containing a poly(3-hydroxyalkanoate) resin, wherein blocking is suppressed and the water resistance of the resin layer is improved, a method for manufacturing the same, and an aqueous dispersion usable in the manufacture of the laminate.

[0019] In the laminate according to the present invention, blocking caused by the uncured state of the poly(3-hydroxyalkanoate) resin contained in the resin layer is unlikely to occur, for example, when the laminate is manufactured while being wound into a roll shape immediately after the resin layer is formed. Further, according to a preferred embodiment of the present invention, blocking can also be suppressed when the laminate is stored or transported in a wound roll shape.

[0020] The laminate according to the present invention has a resin layer with good water resistance, and the resin layer is unlikely to deteriorate even in an environment where it comes into contact with water, and peeling of the resin layer, reduction of adhesion strength or mechanical properties, etc. can be avoided. Therefore, it can be suitably used as a container for containing food and drink products containing water. Further, according to the present invention, since the resin layer can be formed at a relatively low temperature, the energy required for manufacturing can be reduced, and thermal deterioration of the base material and the resin can also be reduced.

[0021] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described below, and various modifications are possible within the scope defined in the claims. Also, each configuration described below can be arbitrarily combined, and such a combination can also be an aspect of the present invention.

[0022] [Laminate] A laminate according to one aspect of the present disclosure includes at least a base material layer (A) and a resin layer (B) laminated on at least one surface of the base material layer (A). The resin layer (B) may be laminated on only one side of the base material layer (A), or may be laminated on both sides of the base material layer (A).

[0023] When the resin layer (B) is laminated on only one side of the base material layer (A), the other surface of the base material layer (A) (the surface on the side where the resin layer (B) is not laminated) may have the base material layer (A) exposed, or a layer other than the resin layer (B) may be laminated.

[0024] The resin layer (B) is preferably laminated directly on the surface of the base material layer (A), but another layer may be further included between the resin layer (B) and the base material layer (A) as long as it does not inhibit adhesion.

[0025] In one aspect of the present disclosure, the resin layer (B) may be the outermost layer exposed on the surface of the laminate. In this case, the resin layer (B) can function as a heat-sealing layer, a water-resistant layer, and / or an oil-resistant layer, etc.

[0026] In another aspect of the present disclosure, another layer may be laminated on the resin layer (B). In this case, the resin layer (B) can function as an anchor coat layer between the base material layer (A) and the said another layer. The said another layer is not particularly limited, and it may be a resin layer or an inorganic layer, and as an example, the resin layer (C) described later can be mentioned.

[0027] [Base material layer (A)] The material constituting the base material layer (A) is not particularly limited, but it is desirable that it is biodegradable. For example, paper (the main component is cellulose), cellophane, cellulose ester; polyvinyl alcohol, polyamino acid, polyglycolic acid, pullulan, or those obtained by vapor-depositing inorganic substances such as aluminum and silica on these base materials, etc. can be mentioned. Among them, paper is preferable from the points of excellent heat resistance and low cost.

[0028] The type of paper is not particularly limited and can be appropriately selected according to the use of the laminate. For example, cup base paper, kraft paper, high-quality paper, coated paper, tissue paper, glassine paper, cardboard, etc. can be mentioned. Water-resistant agents, water-repellent agents, inorganic substances, etc. may be added to the paper as necessary, and those subjected to surface treatments such as oxygen barrier layer coating and water vapor barrier coating may also be used.

[0029] Further, the base material layer (A) may be subjected to surface treatments such as corona treatment, ozone treatment, plasma treatment, frame treatment, anchor coat treatment, oxygen barrier layer coating, water vapor barrier coating, etc. These surface treatments may be performed alone or in combination of a plurality of surface treatments.

[0030] The basis weight of the base material layer (A) can be appropriately selected according to the desired quality, the use of the laminate, etc. Usually, it is preferably 20 g / m ２ or more and 600 g / m ２ or less, and more preferably 25 g / m ２ or more and 600 g / m ２The following is more preferable. When the laminate according to the present disclosure is used for paper tableware such as paper cups, cardboard boxes, paper plates, paper trays, and other paper containers, it is 150 g / m ２ or more and 300 g / m ２ or less is even more preferable.

[0031] [Resin layer (B)] The resin layer (B) contains at least a poly(3-hydroxyalkanoate) resin (b1) and a water-insoluble resin (b2). The resin components contained in the resin layer (B) may be only the poly(3-hydroxyalkanoate) resin (b1) and the water-insoluble resin (b2), or may further contain another resin. Also, components other than the resin may be contained.

[0032] The resin layer (B) is preferably a layer composed of a mixture containing a poly(3-hydroxyalkanoate) resin (b1) and a water-insoluble resin (b2). On the other hand, a two-layer structure formed by laminating a layer containing (b1) and a layer containing (b2) does not correspond to the resin layer (B) referred to in the present application.

[0033] [Poly(3-hydroxyalkanoate) resin (b1)] By blending the poly(3-hydroxyalkanoate) resin (b1) into the resin layer (B), the biodegradability of the resin layer (B), and thus the entire laminate, can be enhanced. Also, when a resin layer (C) containing a poly(3-hydroxyalkanoate) resin (c1) described later is laminated on the resin layer (B), the adhesion strength between the resin layer (B) and the resin layer (C) can be improved.

[0034] In the present specification, the poly(3-hydroxyalkanoate) resin (hereinafter also referred to as P3HA resin) refers to a polymer having 3-hydroxyalkanoate units. Specifically, it is preferably a polymer containing a unit represented by the following general formula (1). [-CHR-CH ２ -CO-O-] (1) In the general formula (1), R is C ｐ H ２ｐ＋１R represents an alkyl group, where p is an integer from 1 to 15. Examples of R include linear or branched alkyl groups such as methyl, ethyl, propyl, methylpropyl, butyl, isobutyl, t-butyl, pentyl, and hexyl groups. p is preferably 1 to 10, and more preferably 1 to 8.

[0035] As for poly(3-hydroxyalkanoate) resins, those produced from microorganisms are particularly preferred. In poly(3-hydroxyalkanoate) resins produced from microorganisms, all 3-hydroxyalkanoate units are contained as (R)-3-hydroxyalkanoate units.

[0036] The poly(3-hydroxyalkanoate) resin preferably contains 50 mol% or more of 3-hydroxyalkanoate units (particularly the unit represented by general formula (1)) of the total constituent units, more preferably 60 mol% or more, and even more preferably 70 mol% or more. The poly(3-hydroxyalkanoate) resin may contain only 3-hydroxyalkanoate units as constituent units of the polymer, or it may contain one or more types of 3-hydroxyalkanoate units in addition to other units (for example, 4-hydroxyalkanoate units).

[0037] The poly(3-hydroxyalkanoate) resin preferably includes a homopolymer having only 3-hydroxybutyrate units, and / or a copolymer containing 3-hydroxybutyrate units and other hydroxyalkanoate units. In particular, from the viewpoint of seawater degradability, it is preferable to include a copolymer containing 3-hydroxybutyrate units and other hydroxyalkanoate units.

[0038] The form of copolymerization in the aforementioned copolymer is not particularly limited and may include random copolymerization, alternating copolymerization, block copolymerization, graft copolymerization, etc. Copolymers produced by microorganisms are usually random copolymers.

[0039] The hydroxyalkanoic acid that forms the aforementioned other hydroxyalkanoate units is not particularly limited and includes, for example, 4-hydroxybutanoic acid, 3-hydroxypropionic acid, 3-hydroxypentanoic acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, and 3-hydroxyoctanoic acid.

[0040] Specific examples of P3HA resins include poly(3-hydroxybutyrate) (abbreviation: PHB), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (abbreviation: P3HB3HH), poly(3-hydroxybutyrate-co-3-hydroxyvariate) (abbreviation: P3HB3HV), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (abbreviation: P3HB4HB), and poly(3-hydroxybutyrate-co- Examples include poly(3-hydroxyoctanoate) (abbreviated as P3HB3HO), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate) (abbreviated as P3HB3HOD), poly(3-hydroxybutyrate-co-3-hydroxydecanoate) (abbreviated as P3HB3HD), and poly(3-hydroxybutyrate-co-3-hydroxyvalarylate-co-3-hydroxyhexanoate) (abbreviated as P3HB3HV3HH). Among these, PHB, P3HB3HH, P3HB3HV, and P3HB4HB are preferred because they are easy to produce industrially. P3HB may be used alone or in combination of two or more types.

[0041] Specific manufacturing methods for poly(3-hydroxyalkanoate) resins are described, for example, in International Publication No. 2010 / 013483. Commercially available P3HB3HH products include Kaneka Corporation's "Kaneka Biodegradable Polymer Green Planet" (registered trademark).

[0042] The poly(3-hydroxyalkanoate) resin (b1) contained in the resin layer (B) preferably contains a copolymer (b1-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units.

[0043] Specific examples of the copolymer (b1-1) include the copolymers mentioned above, of which P3HB3HH, P3HB3HV, and P3HB4HB are preferred, with P3HB3HH being particularly preferred.

[0044] The content of other hydroxyalkanoate units in the copolymer (b1-1) relative to the total monomer units is preferably 4 to 12 mol%. A content of 12 mol% or less facilitates the formation of a resin (b1) having a peak top temperature in the range of 100°C or higher in the crystal melting curve. This suppresses the melting of the resin (b1) during heat treatment after coating with the aqueous dispersion described later, thereby suppressing the occurrence of blocking caused by the unsolidified resin (b1) immediately after the formation of the resin layer (B). It also suppresses the progression of blocking when stored at high temperatures. A content of 11 mol% or less is more preferable.

[0045] Furthermore, by having a content of 4 mol% or more, it becomes easy to construct a resin (b1) having a peak top temperature in the range of 150°C or less in the crystal melting curve. This allows the resin (b1) to be softened or slightly melted during the heat treatment after coating with the aqueous dispersion, thereby forming a resin layer (B) with good adhesion strength. The content is more preferably 6 mol% or more, and even more preferably 8 mol% or more.

[0046] The average content ratio of each monomer unit to the total monomer units constituting the poly(3-hydroxyalkanoate) resin can be determined by methods known to those skilled in the art, for example, by the method described in paragraph

[0047] of International Publication 2013 / 147139. The average content ratio means the molar ratio of each monomer unit to the total monomer units constituting the poly(3-hydroxyalkanoate) resin, and if the resin being measured is a mixture of two or more resins, it means the molar ratio of each monomer unit contained in the entire mixture.

[0047] The weight-average molecular weight of the copolymer (b1-1) is not particularly limited, but from the viewpoint of achieving both the applicability of the coating liquid and the mechanical properties of the resin layer (B), it is preferably 100,000 to 650,000, more preferably 150,000 to 450,000, and even more preferably 200,000 to 350,000.

[0048] The weight-average molecular weight (hereinafter sometimes referred to as Mw) of a polymer can be determined by gel permeation chromatography (GPC) (Showa Denko's "Shodex GPC-101") using a polystyrene gel column (Showa Denko's "Shodex K-804") with chloroform as the mobile phase, and expressed as the molecular weight in terms of polystyrene equivalent.

[0049] The resin layer (B) preferably contains poly(3-hydroxyalkanoate) resin (b1) as a polymer (b1-1) and further contains poly(3-hydroxybutyrate) (b1-2). This makes it easy to construct a resin (b1) having a peak top temperature (Tmb) in the range of 150 to 170°C in the crystal melting curve, and can promote solidification after resin melting, such as when the resin layer (B) is used as a heat seal layer.

[0050] Poly(3-hydroxybutyrate)(b1-2) refers to a homopolymer composed solely of 3-hydroxybutyrate, or a polymer containing trace amounts of hydroxyalkanoate units other than 3-hydroxybutyrate units. Specifically, it is preferable that poly(3-hydroxybutyrate)(b1-2) has a content of 3-hydroxybutyrate units in the total constituent monomers that is greater than 99 mol% and less than or equal to 100 mol%.

[0051] The hydroxyalkanoate units other than 3-hydroxybutyrate units that may be included in poly(3-hydroxybutyrate)(b1-2) are not particularly limited as long as they can copolymerize with 3-hydroxybutyrate units, but examples include 3-hydroxyalkanoate units other than 3-hydroxybutyrate units, and hydroxyalkanoate units other than 3-hydroxyalkanoate units (e.g., 4-hydroxyalkanoate units). 3-hydroxyhexanoate units are particularly preferred.

[0052] The weight-average molecular weight of poly(3-hydroxybutyrate)(b1-2) is not particularly limited, but from the viewpoint of achieving both the applicability of the coating liquid and the mechanical properties of the resin layer (B), it is preferably 100,000 to 450,000, and more preferably 200,000 to 350,000.

[0053] From the viewpoint of achieving both accelerated solidification after resin melting and good adhesion strength of resin (B), the content of poly(3-hydroxybutyrate) (b1-2) in the resin layer (B) is preferably 1% by weight or more and 50% by weight or less of the total of copolymer (b1-1) and poly(3-hydroxybutyrate) (b1-2). From the viewpoint of accelerating solidification after resin melting, this content is more preferably 3% by weight or more, and even more preferably 5% by weight or more. Furthermore, from the viewpoint of adhesion strength of resin layer (B), it is preferably 30% by weight or less, more preferably 20% by weight or less, and even more preferably 10% by weight or less.

[0054] The average content of other hydroxyalkanoate units in the total monomer units contained in the poly(3-hydroxyalkanoate) resin (b1) contained in the resin layer (B) is preferably 4 to 12 mol%, more preferably 6 to 12 mol%, and particularly preferably 8 to 11 mol%, from the viewpoint of achieving both blocking suppression and adhesion strength of the resin layer (B).

[0055] The total weight-average molecular weight of the poly(3-hydroxyalkanoate) resin (b1) contained in the resin layer (B) is not particularly limited, but from the viewpoint of achieving both the applicability of the coating liquid and the mechanical properties of the resin layer (B), it is preferably between 100,000 and 450,000, and more preferably between 200,000 and 350,000.

[0056] [Melting characteristics of resin (b1)] The poly(3-hydroxyalkanoate) resin (b1) has at least one peak top temperature (Tma) in the range of 100 to 150°C in the crystal melting curve obtained by differential scanning calorimetry. Because the resin (b1) has a melting peak at 100°C or higher, the melting of the resin (b1) is suppressed during heat treatment after coating with an aqueous dispersion. This makes it possible to suppress the occurrence of blocking caused by the unsolidified resin (b1) immediately after the formation of the resin layer (B). It is also possible to suppress the progression of blocking when stored at high temperatures. Preferably, it is 105°C or higher, and more preferably 110°C or higher.

[0057] Furthermore, since the resin (b1) has a melting peak at 150°C or below, the resin (b1) can be softened or slightly melted during the heat treatment after coating with the aqueous dispersion, thereby forming a resin layer (B) with good adhesion strength. Preferably, the temperature is 140°C or below, more preferably 130°C or below, and even more preferably 120°C or below.

[0058] From the viewpoint of suppressing the melting of the resin (b1) during heat treatment after coating with an aqueous dispersion, it is preferable that the resin (b1) does not have a melting peak in the range of less than 100°C.

[0059] The resin (b1) may have a melting peak only in the range of 100 to 150°C, but may also have a melting peak in the range of 150°C or higher. That is, in the crystal melting curve obtained by differential scanning calorimetry, the resin (b1) may have at least one peak top temperature (Tmb) in the range of 150 to 170°C in addition to Tma.

[0060] Because the resin (b1) has a melting point peak in the relatively high temperature range of 150 to 170°C, when the resin (b1) is melted, such as when the resin layer (B) is used as a heat seal layer, the high-melting-point resin crystals with Tmb act as crystal nuclei, thereby accelerating the solidification of the resin (b1) after melting. As a result, good adhesive strength can be achieved in a short time after heat sealing.

[0061] To enjoy the benefits of Tmb, it is preferable that there is a certain temperature difference between Tma and Tmb. Specifically, it is preferable that the temperature difference between Tma and Tmb be 10°C or more. More preferably, it is 20°C or more, and even more preferably 30°C or more. There is no particular upper limit to this temperature difference, but from the viewpoint of ease of manufacturing, it is preferable that it be 70°C or less, and more preferably 60°C or less.

[0062] In this specification, the peak top temperature of the crystal melting curve in differential scanning calorimetry is defined as follows: 2 to 5 mg of the resin to be measured is filled into an aluminum pan, and the resin is melted using a differential scanning calorimetry analyzer under a nitrogen stream at a rate of 10°C / min from 20°C to 190°C to obtain a crystal melting curve. In the obtained crystal melting curve, the top temperature of the melting point peak in the range of 100 to 150°C is defined as Tma, and the top temperature of the melting point peak in the range of 150 to 170°C is defined as Tmb.

[0063] [Water-insoluble resin (b2)] The resin layer (B) contains a water-insoluble resin (b2) in addition to the poly(3-hydroxyalkanoate) resin (b1). By incorporating the water-insoluble resin (b2) into the resin layer (B), it becomes possible to adhere the resin layer (B) to the substrate layer (A) even if the poly(3-hydroxyalkanoate) resin (b1) is not substantially melted during the heat treatment after coating with an aqueous dispersion. Furthermore, because the resin (b2) is water-insoluble, the water resistance of the laminate can be improved. Therefore, even when the laminate is used in applications that come into contact with water, specifically as a container for food and beverages containing water, such as paper cups and paper pouches, peeling of the resin layer (B) and a decrease in adhesion strength or mechanical properties can be avoided.

[0064] In the context of water-insoluble resins (b2), "water-insoluble" means that the resin does not readily dissolve in water. More specifically, a water-insoluble resin is defined as one that, when immersed in water at room temperature (25°C), can be visually recognized as maintaining its original shape even after 24 hours, and more preferably after 72 hours. However, water-insoluble resins (b2) do not include poly(3-hydroxyalkanoate) resins (b1).

[0065] It is preferable to use a water-insoluble resin (b2) with a glass transition temperature greater than 0°C and 75°C or less. If the glass transition temperature of the water-insoluble resin (b2) is greater than 0°C, the tackiness of the water-insoluble resin (b2) is suppressed even at high temperatures, and the progression of blocking during storage and transportation of the laminate can be suppressed. The lower limit of the glass transition temperature is preferably 10°C or higher, more preferably 30°C or higher, and even more preferably 50°C or higher.

[0066] If the glass transition temperature of the water-insoluble resin (b2) is 75°C or lower, the water-insoluble resin (b2) can be softened and bonded by heat treatment after coating with an aqueous dispersion, making it easier to attach the resin layer (B) to the substrate layer (A). Furthermore, the occurrence of cracks in the resin layer (B) at or near room temperature can be suppressed. The lower limit of the glass transition temperature may be 70°C or lower.

[0067] The glass transition temperature of the water-insoluble resin (b2) can be controlled by adjusting the type of monomers that make up the resin and their usage ratio. Furthermore, the glass transition temperature can be measured by differential thermal analysis.

[0068] The acid value exhibited by the non-water-soluble resin (b2) is not particularly limited, but may be in the range of 0 to 120 mgKOH / g. From the viewpoint of resin productivity and the effect on the physical properties of the laminate, it is preferably 100 mgKOH / g or less, and more preferably 80 mgKOH / g or less. Furthermore, from the viewpoint of adhesion strength between the substrate layer (A) and the resin layer (B), it is preferably 5 mgKOH / g or more.

[0069] The acid value of a resin is determined by the acidic groups, such as carboxyl groups, present in the resin. The higher the content of acidic groups, the higher the acid value. Specifically, the acid value of a resin is expressed as the mass (mg) of potassium hydroxide required to neutralize 1 g of the resin.

[0070] The type of water-insoluble resin (b2) is not particularly limited; any water-insoluble resin can be appropriately selected and used from among those commonly known as binder resins.

[0071] Specifically, examples of water-insoluble resins (b2) include acrylic resins, polyester resins, vinyl chloride resins, styrene-butadiene resins, styrene-isoprene resins, styrene-maleic anhydride resins, polycarbonate resins, urea resins, melamine resins, epoxy resins, phenolic resins, urethane resins, diallyl phthalate resins, imine resins, and the like. These may be used individually or mixed in any proportion of two or more resins.

[0072] As the water-insoluble resin (b2), a resin having an ester structure is preferred because it has good compatibility with the poly(3-hydroxyalkanoate) resin (b1) and can form a resin layer (B) with high adhesion strength. As such a resin having an ester structure, acrylic resins and / or polyester resins are preferred.

[0073] The aforementioned acrylic resin refers to a resin containing at least an acrylic monomer and / or a methacrylic monomer as constituent monomers.

[0074] The acrylic monomer or methacrylic monomer is not particularly limited, but examples include alkyl esters of (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, alkyl (meth)acrylate, stearyl (meth)acrylate, and cyclohexyl (meth)acrylate; phenyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, allyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, and 2-ethoxyethyl (meth)acrylate; and (meth)acrylic acid. You may use only one type, or you may use two or more types in combination.

[0075] Among the (meth)acrylic monomers listed above, methyl methacrylate in particular is known to form resins with high glass transition temperatures. Furthermore, butyl acrylate and 2-ethylhexyl acrylate are known monomers that lower the glass transition temperature of resins.

[0076] From the viewpoint of satisfying the aforementioned glass transition temperature, the acrylic resin is preferably one that contains methacrylic acid ester as a monomer unit, and particularly preferably one that contains methyl methacrylate as a monomer unit. The glass transition temperature of the acrylic resin can be controlled by adjusting the content of methacrylic acid ester or methyl methacrylate. From this viewpoint, the content of methacrylic acid ester or methyl methacrylate is preferably 30 mol% or more, and more preferably 50 mol% or more, of the total monomer units of the acrylic resin. The upper limit of this content is preferably 90 mol% or less, and more preferably 80 mol% or less.

[0077] The acrylic resin may contain other vinyl monomers copolymerizable with (meth)acrylic acid esters. Such vinyl monomers are not particularly limited, but examples include aromatic vinyl compounds such as styrene and α-methylstyrene; and olefins such as ethylene. The content of such other vinyl monomers is not particularly limited, but is preferably 60 mol% or less, and more preferably 40 mol% or less, of the total monomer units of the acrylic resin. The lower limit is preferably, for example, 5 mol% or more, and more preferably 10 mol% or more.

[0078] The polyester resins that can be used as water-insoluble resins (b2) are not particularly limited, but include those whose main components are polyalcohols and polycarboxylic acids, those whose main components are aliphatic oxycarboxylic acids, or those whose components include polyalcohols and polycarboxylic acids in addition to aliphatic oxycarboxylic acids. Examples include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN); aliphatic polyester resins such as polycaprolactone, polybutylene succinate adipate, polybutylene succinate, and polylactic acid; and aliphatic aromatic polyester resins such as polybutylene adipate terephthalate, polybutylene sebatate terephthalate, and polybutylene azelate terephthalate.

[0079] Examples of the polyalcohol component include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol; alicyclic diols such as 1,4-cyclohexanedimethanol; aromatic diols such as 1,4-benzenedimethanol and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene; and ether group-containing diols such as diethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, and polytetramethylene ether glycol.

[0080] As the polyalcohol component, a branched-chain diol component can also be used. Specific examples include neopentyl glycol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-pentanediol, 1,2-hexanediol, 2,5-hexanediol, and 2,4-diethyl-1,5-pentanediol. Only one type of polyalcohol component may be used, or two or more types may be used in combination.

[0081] Furthermore, as the polyalcohol component, a trivalent or higher alcohol component may be used in combination with the diol component as described above. Specific examples of trivalent or higher alcohol components include aliphatic triols such as glycerin and trimethylolpropane; alicyclic triols such as 1,2,4-cyclohexanetrimethanol; triol compounds such as aromatic triols such as benzenetrimethanol; and tetraol compounds such as pentaerythritol.

[0082] Examples of the polycarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 2,5-frandicarboxylic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; and dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedioic acid, their esters, and their anhydrides. Only one of these may be used, or two or more may be used in combination.

[0083] Examples of polycarboxylic acids with a valency of three or higher include hemimellitic acid, trimellitic acid, trimedic acid, merophanic acid, pyromellitic acid, benzenepentacarboxylic acid, meritolic acid, cyclopropane-1,2,3-tricarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, and ethanetetracarboxylic acid. Esters or anhydrides of these may also be used. Only one of these may be used, or two or more may be used in combination. Polyester resins formed by dehydration condensation of a diol component, a dicarboxylic acid component, and a polycarboxylic acid with a valency of three or higher can exhibit a high acid value.

[0084] In the resin layer (B), the mixing ratio of the poly(3-hydroxyalkanoate) resin (b1) and the water-insoluble resin (b2) is not particularly limited and can be set appropriately considering the effects of the invention. By increasing the proportion of resin (b1), the biodegradability of the resin layer (B) can be increased, and if the resin layer (C) is provided on top of the resin layer (B), the adhesion strength between the resin layer (B) and the resin layer (C) can be improved. Furthermore, by increasing the proportion of the water-insoluble resin (b2), the adhesion of the resin layer (B) to the substrate layer (A) can be increased.

[0085] From the viewpoint of balancing these effects, the dry weight ratio of (b1):(b2) in the resin layer (B) is preferably 20:80 to 95:5, more preferably 30:70 to 90:10, even more preferably 40:60 to 80:20, and particularly preferably 50:50 to 70:30.

[0086] The resin layer (B) is a layer whose main components are resin (b1) and water-insoluble resin (b2). The total content ratio of resin (b1) and water-insoluble resin (b2) in the resin layer (B) is preferably 50% by weight or more, and more preferably 70% by weight or more. It may be 80% by weight or more, or 90% by weight or more. The upper limit may be 100% by weight or less, or 99% by weight or less.

[0087] [Water-soluble resin (b3)] The resin layer (B) may contain a water-soluble resin (b3) in addition to the resin (b1) and the water-insoluble resin (b2). If a water-soluble resin (b3) is used in the resin layer without using the water-insoluble resin (b2), the water resistance of the resin layer will be greatly reduced. However, if a water-soluble resin (b3) is used together with the water-insoluble resin (b2), the water resistance of the resin layer (B) may be good. The water-soluble resin (b3) is a component that can function as a dispersant for dispersing the resins in water in an aqueous dispersion containing the resin (b1) and water-insoluble resin (b2) described later.

[0088] Examples of water-soluble resins (b3) that can be used in the resin layer (B) include polyvinyl alcohol derivatives such as fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, sulfonated polyvinyl alcohol, and ethylene-modified polyvinyl alcohol; cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, and hydroxypropylcellulose; starch derivatives such as starch, oxidized starch, or etherified starch; chitin, chitosan, casein, and gum arabic. These water-soluble resins may be used individually or in combination of two or more types.

[0089] From the viewpoint of water resistance of the resin layer (B), the amount of water-soluble resin (b3) blended in the resin layer (B) is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and even more preferably 2 parts by weight or less, per 100 parts by weight of the total of resin (b1) and non-water-soluble resin (b2). The lower limit is not particularly limited and may be 0 parts by weight or more, but from the viewpoint of improving dispersibility, it is preferably 0.1 parts by weight or more, and more preferably 0.5 parts by weight or more.

[0090] The resin layer (B) may contain one or more resins other than the poly(3-hydroxyalkanoate) resin (b1), the water-insoluble resin (b2), and the water-soluble resin (b3), to the extent that they do not impair the effects of the invention. The amount of such other resins added may be 30 parts by weight or less, 20 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less, based on 100 parts by weight of the total of the resin (b1) and the water-insoluble resin (b2). The lower limit is not particularly limited, and it is sufficient if it is 0 parts by weight or more.

[0091] The resin layer (B) may contain additives commonly used in the art, to the extent that the effects of the invention are achieved. Examples of such additives include inorganic fillers such as talc, calcium carbonate, mica, silica, titanium dioxide, and alumina; organic fillers such as rice husks, wood flour, 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-resistant modifiers, ultraviolet absorbers, crystal nucleating agents, lubricants, mold release agents, water repellents, antibacterial agents, sliding properties modifiers, tackifiers, fillers, and chemicals. Only one type of additive may be included, or two or more types may be included. The content of these additives can be appropriately determined by a person skilled in the art depending on the intended use.

[0092] The resin layer (B) is preferably a coating layer of a coating liquid, and is particularly preferably a coating layer of a water-based coating liquid. This makes it possible to form the resin layer (B) simply by applying the coating liquid and then performing a heat drying treatment, resulting in good productivity of the laminate.

[0093] The basis weight of the resin layer (B) is not particularly limited and can be set appropriately according to the performance required for the resin layer (B), but for example, 0.5 g / m² in dry weight. ２ 50g / m or more ２ The following range is acceptable. The lower limit is 1 g / m², as this improves water resistance and adhesion. ２ It is more preferable that the amount be greater than or equal to 3 g / m ２ The above is even more preferable, 5 g / m ２ The above is even more preferable at 8 g / m ２The above is particularly preferable. The upper limit is 30 g / m², as this reduces the energy required for the heat treatment necessary for forming the resin layer (B). ２ More preferably, the following is true: 20 g / m ２ The following are even more preferable.

[0094] If the resin layer (B) is the outermost layer exposed on the surface of the laminate, the resin layer (B) can function as a heat seal layer. A heat seal layer is a layer that has heat sealability, and specifically, is a layer that can be bonded to an object by heat and pressure. The object to be bonded may be the same heat seal layer, the base layer (A), the resin layer (C), or an article made of other materials.

[0095] [Method for forming the resin layer (B)] As a method for forming the resin layer (B), extrusion lamination or heat lamination may be used, but a preferred method is to apply an aqueous dispersion (also called an "aqueous coating liquid"), in which a resin (b1) and a water-insoluble resin (b2) are dispersed in water, to the surface of the substrate and heat and dry it (also called a "coating method"). In particular, when using a paper substrate, it is preferable to use the coating method because a portion of the aqueous dispersion soaks into the paper substrate, which further improves the adhesion between the substrate layer (A) and the resin layer (B). An aqueous dispersion that can be used in the coating method also constitutes one aspect of the present invention.

[0096] The aqueous dispersion containing resin (b1) and water-insoluble resin (b2) may contain only water as the medium, or it may contain water plus an organic solvent that is compatible with water. Such organic solvents are not particularly limited, but examples include methanol, ethanol, 1-propanol, 2-propanol, butanol, acetone, methyl ethyl ketone, and 1,3-dioxolane. The water content in the aqueous dispersion is preferably 50% by weight or more, more preferably 70% by weight or more, and even more preferably 90% by weight or more. There is no particular upper limit, and it may be 100% by weight or less.

[0097] The solid content concentration of the aqueous dispersion is not particularly limited, but is preferably 20% by weight or more, and more preferably 30% by weight or more, in order to suppress dripping when coating the substrate and to improve drying after coating. Furthermore, from the viewpoint of ensuring coatability during coating, the upper limit of the solid content concentration is preferably 65% ​​by weight or less, and more preferably 55% by weight or less.

[0098] The method for preparing the aqueous dispersion is not particularly limited, but it can be prepared by preparing an aqueous dispersion containing resin (b1) and an aqueous dispersion containing water-insoluble resin (b2), and mixing the two dispersions. Alternatively, it can be prepared by adding powder of resin (b1) to an aqueous dispersion containing water-insoluble resin (b2), or conversely, by adding powder of water-insoluble resin (b2) to an aqueous dispersion containing resin (b1).

[0099] An aqueous dispersion containing resin (b1) can be prepared, for example, by referring to International Publication No. 2021 / 075412, etc.

[0100] The method for applying the 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 aqueous dispersion, a surface treatment such as corona treatment may be performed on the substrate.

[0101] After applying the aqueous dispersion to the substrate, a heat treatment is performed. This evaporates the water contained in the aqueous dispersion and dries it, while simultaneously softening and binding the water-insoluble resin (b2), thereby allowing the resin layer (B) to adhere to the substrate layer (A). Preferably, this heat treatment prevents the poly(3-hydroxyalkanoate) resin (b1) from melting, or from melting only slightly. This makes it possible to suppress the occurrence of blocking caused by the unsolidified resin (b1) immediately after the formation of the resin layer (B).

[0102] From the above viewpoint, the heating temperature in the heat treatment is preferably 95°C to 120°C. By heating at 120°C or lower, the melting of the resin (b1) having a peak top temperature (Tma) in the range of 100 to 150°C can be suppressed. More preferably, it is 110°C or lower, and even more preferably 105°C or lower. Furthermore, by heating at 95°C or higher, the water-insoluble resin (b2) can be softened and bonded while evaporating the water. More preferably, it is 100°C or higher. In addition, since the heating is performed at a relatively low temperature, thermal degradation of the base layer (A) and the resin layer (B) can be reduced.

[0103] The heating time in the heat treatment is not particularly limited and can be set as appropriate, but for example it may be 10 seconds to 10 minutes, and preferably 30 seconds to 5 minutes.

[0104] Heat treatment can be carried out using known heating methods. Examples include hot air heating, infrared heating, ultrasonic irradiation, microwave heating, roll heating, and hot plate heating. These can be used individually or in combination of two or more methods.

[0105] [Resin layer (C)] In a laminate according to another embodiment of the present disclosure, a resin layer (C) may be further laminated on top of the resin layer (B). In this embodiment, the base layer (A), the resin layer (B), and the resin layer (C) are laminated in this order. By providing the resin layer (C), it is possible to impart a high level of water resistance and oil resistance to the laminate. The resin layer (B) functions as an anchor coat layer between the base layer (A) and the resin layer (C), and can improve the adhesion strength between the base layer (A) and the resin layer (C).

[0106] It is preferable that the resin layer (C) is directly laminated on the surface of the resin layer (B), but another layer may be included between the resin layer (C) and the resin layer (B) as long as it does not impede adhesion.

[0107] The resin layer (C) may be the outermost layer exposed on the surface of the laminate, or another layer may be laminated on top of the resin layer (C).

[0108] Specific embodiments including the resin layer (C) include a configuration in which the resin layer (B) and resin layer (C) are laminated on only one side of the base layer (A). Another configuration includes a configuration in which the resin layer (B) and resin layer (C) are laminated on both sides of the base layer (A). Yet another configuration includes a configuration in which the resin layer (B) and resin layer (C) are laminated on one side of the base layer (A), and only the resin layer (B) is laminated on the other side.

[0109] The resin layer (C) preferably contains a biodegradable resin and exhibits biodegradability. This enhances the overall biodegradability of the laminate. Examples of usable biodegradable resins include poly(3-hydroxyalkanoate) resins, aliphatic polyester resins, and aliphatic aromatic polyester resins.

[0110] From the viewpoint of affinity with resin layer (B), it is preferable that resin layer (C) contains a poly(3-hydroxyalkanoate) resin (c1). This can further improve the adhesion between resin layer (B) containing the poly(3-hydroxyalkanoate) resin (b1) and resin layer (C). Resin layer (C) does not need to contain the aforementioned water-insoluble resin (b2).

[0111] The resin layer (C) preferably contains 50% by weight or more of poly(3-hydroxyalkanoate) resin (c1), more preferably 70% by weight or more, even more preferably 80% by weight or more, and even more preferably 90% by weight or more. It may also contain 95% by weight or more. The resin component contained in the resin layer (C) may consist only of poly(3-hydroxyalkanoate) resin (c1), or it may also contain other resins.

[0112] As the poly(3-hydroxyalkanoate) resin (c1), the poly(3-hydroxyalkanoate) resins already described above can be used. In particular, it is preferable that the resin (c1) contains a copolymer (c1-1) comprising a 3-hydroxybutyrate unit and other hydroxyalkanoate units. Among these, P3HB3HH, P3HB3HV, and P3HB4HB are preferred, and P3HB3HH is particularly preferred.

[0113] The proportion of other hydroxyalkanoate units to the total monomer units in the copolymer (c1-1) is not particularly limited and can be set appropriately considering the mechanical strength and productivity of the resin layer (C). Furthermore, multiple copolymers with different proportions of other hydroxyalkanoate units may be used in combination as the copolymer (c1-1).

[0114] As the copolymer (c1-1), it is preferable to use a copolymer in which the content of other hydroxyalkanoate units is 24 mol% or more, and it is more preferable to use this copolymer in combination with a copolymer in which the content of other hydroxyalkanoate units is less than 24 mol%. This makes it easier to achieve both mechanical strength and productivity of the resin layer (C).

[0115] Furthermore, part or all of the copolymer (c1-1) may be modified with an organic peroxide. Modification with an organic peroxide allows the molecular chains of the copolymer (c1-1) to be directly bonded together, thereby improving the physical properties of the resin layer (C), such as its crack resistance.

[0116] Examples of organic peroxides include diacyl peroxides, alkyl peroxyesters, dialkyl peroxides, hydroperoxides, peroxyketals, peroxycarbonates, and peroxydicarbonates.

[0117] The resin layer (C) preferably contains 50% by weight or more of copolymer (c1-1), more preferably 70% by weight or more, even more preferably 80% by weight or more, and even more preferably 90% by weight or more. It may also contain 95% by weight or more. The resin component contained in the resin layer (C) may be copolymer (c1-1) alone, or it may also contain other resins.

[0118] The resin layer (C) may contain additives that are commonly 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. The content of these components can be appropriately adjusted according to the desired physical properties. However, the additives are arbitrary components, and the resin layer (C) may not contain these additives.

[0119] Examples of the aforementioned crystal nucleating agents include polyhydric alcohols such as pentaerythritol, galactitol, and mannitol; orotic acid, aspartame, cyanuric acid, glycine, zinc phenylphosphonate, and boron nitride. Among these, pentaerythritol is preferred because it is particularly effective in promoting the crystallization of poly(3-hydroxyalkanoate) resins.

[0120] Examples of the aforementioned lubricants include behenamide, oleamide, erucamide, stearamide, palmitamide, N-stearylbehenamide, N-stearylerucamide, ethylenebisstearateamide, ethylenebisoleamide, ethylenebiserucamide, ethylenebislaurylamide, ethylenebiscaprateamide, p-phenylenebisstearateamide, and polycondensates of ethylenediamine, stearic acid, and sebacic acid. Among these, behenamide or erucamide are preferred because they have particularly excellent lubricating effects on poly(3-hydroxyalkanoate) resins.

[0121] Examples of the inorganic filler include talc, calcium carbonate, mica, silica, clay, kaolin, titanium dioxide, alumina, and zeolite.

[0122] The plasticizer is not particularly limited, but from the viewpoint of compatibility with poly(3-hydroxyalkanoate) resins, it is preferable to use an ester compound having an ester bond in the molecule. Examples of usable ester compounds include modified glycerin compounds, dibasic acid ester compounds, adipic acid ester compounds, polyether ester compounds, benzoic acid ester compounds, phthalic acid ester compounds, citrate ester compounds, sebacate acid ester compounds, isosorbide ester compounds, and polycaprolactone compounds. Among these, modified glycerin compounds, dibasic acid ester compounds, adipic acid ester compounds, polyether ester compounds, citrate ester compounds, sebacate acid ester compounds, or isosorbide ester compounds are preferred, and modified glycerin compounds are particularly preferred.

[0123] As the modified glycerin-based compound, glycerin ester compounds are preferred. As the glycerin ester compound, any of glycerin monoester, diester, or triester can be used, but from the viewpoint of compatibility with poly(3-hydroxyalkanoate) resins, glycerin triester is preferred.

[0124] The basis weight of the resin layer (C) is not particularly limited and can be determined as appropriate considering the performance and productivity required for the resin layer (C), but for example, 5 to 100 g / m² ２ It can be around 10-80 g / m ２ Preferably, it is 20 to 60 g / m ２ This is more preferable. It is preferable that the basis weight of resin layer (C) is greater than the basis weight of resin layer (B).

[0125] [Method for forming resin layer (C)] The coating method described above may be used to form the resin layer (C) on top of the resin layer (B). However, from the viewpoint of adhesion to the resin layer (B) and production, it is preferable to form the resin layer (C) by extrusion lamination or heat lamination.

[0126] As the aforementioned extrusion lamination method, a general extrusion lamination method can be used. Specifically, a molten resin material is extruded in a film shape from a T-type die, cooled using a cooling roll, and pressed onto the surface of the resin layer (B) of the laminate. Immediately afterward, the resin material is peeled off from the cooling roll to form a resin layer (C), thereby producing a three-layer laminate.

[0127] 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 molded film containing the resin material is obtained while cooling it using a cooling roll. Next, the obtained molded film is pressed onto the surface of the resin layer (B) of the laminate using a heating roll or the like to produce a three-layer laminate.

[0128] For purposes such as improving the adhesion between resin layer (C) and resin layer (B), the surface of resin layer (B) may be subjected to corona treatment, flame treatment, plasma treatment, ozone treatment, etc.

[0129] [Molded Article] A molded article according to one aspect of the present disclosure (hereinafter sometimes referred to as "the Molded Article") includes the Laminate and has a desired size and shape. The Molded Article is advantageous in various applications.

[0130] 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), bag, part, etc.

[0131] In one embodiment of this disclosure, the molded article may be the laminate itself, or the laminate may be a product of secondary processing.

[0132] Because this laminate is subjected to secondary processing, the molded product containing it can be used in various fields such as food, cosmetics, electronics, medical, and pharmaceuticals as a material for various packaging containers such as shopping bags, various types of bags, food and confectionery packaging materials, cups, trays, and cartons. Because this laminate has good water resistance, it can be suitably used as a bag or container for food and beverages containing water. Examples of such containers include, but are not limited to, paper cups, cups for instant noodles, instant soup, coffee, etc., and trays used for prepared foods, bento boxes, microwaveable foods, etc.

[0133] Secondary processing can be carried out using the same methods as conventional resin-laminated paper or coated paper, i.e., 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 laminate, such as heat sealing, impulse sealing, ultrasonic sealing, high-frequency sealing, hot air sealing, and flame sealing.

[0134] Furthermore, in order to improve its physical properties, this molded body can 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.). It is preferable that these materials are also biodegradable.

[0135] The following items list preferred embodiments of the present disclosure, but the present invention is not limited to these items. [Item 1] A laminate comprising a base layer (A) and a resin layer (B) provided on at least one surface of the base layer, wherein the resin layer (B) contains a poly(3-hydroxyalkanoate) resin (b1) and a water-insoluble resin other than the resin (b1) (b2), and the poly(3-hydroxyalkanoate) resin (b1) has at least one peak-top temperature (Tma) in the range of 100 to 150°C in the crystal melting curve obtained by differential scanning calorimetry. [Item 2] The laminate according to Item 1, wherein the water-insoluble resin (b2) has a glass transition temperature greater than 0°C to 75°C or less. [Item 3] The laminate according to Item 1 or 2, wherein the dry weight ratio of the poly(3-hydroxyalkanoate) resin (b1) to the water-insoluble resin (b2) is 30:70 to 90:10. [Item 4] The laminate according to any one of Items 1 to 3, wherein the water-insoluble resin (b2) is at least one selected from the group consisting of acrylic resins and polyester resins. [Item 5] The laminate according to any one of Items 1 to 4, wherein the poly(3-hydroxyalkanoate) resin (b1) contains a copolymer (b1-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units. [Item 6] The laminate according to Item 5, wherein the content of the other hydroxyalkanoate units in the copolymer (b1-1) is 4 to 12 mol%. [Item 7] The laminate according to any one of Items 1 to 6, wherein the poly(3-hydroxyalkanoate) resin (b1) further has at least one peak top temperature (Tmb) in the range of 150 to 170°C in the crystal melting curve obtained by differential scanning calorimetry, and the temperature difference between Tma and Tmb is 10°C or more. [Item 8] The laminate according to any one of Items 1 to 7, further comprising a resin layer (C) containing a poly(3-hydroxyalkanoate) resin (c1) laminated on the resin layer (B). [Item 9] A molded article comprising the laminate according to any one of Items 1 to 8.[Item 10] A method for manufacturing a laminate, comprising the steps of: applying an aqueous dispersion containing a poly(3-hydroxyalkanoate) resin (b1) having at least one peak top temperature (Tma) in the range of 100 to 150°C in the crystal melting curve obtained by differential scanning calorimetry, and a water-insoluble resin (b2) other than resin (b1) to at least one surface of a base layer (A); and heating and drying at 95 to 120°C to form a resin layer (B) on the base layer (A). [Item 11] The method for manufacturing a laminate according to item 10, wherein the water-insoluble resin (b2) has a glass transition temperature greater than 0°C to 75°C or less. [Item 12] The method for manufacturing a laminate according to item 10 or 11, further comprising the step of forming a resin layer (C) containing a poly(3-hydroxyalkanoate) resin (c1) on the resin layer (B). [Item 13] An aqueous dispersion comprising a poly(3-hydroxyalkanoate) resin (b1) and a water-insoluble resin other than resin (b2) dispersed in water, wherein the poly(3-hydroxyalkanoate) resin (b1) has at least one peak top temperature (Tma) in the range of 100 to 150°C in the crystal melting curve obtained by differential scanning calorimetry. [Item 14] A method for producing a laminate according to Item 13, wherein the water-insoluble resin (b2) has a glass transition temperature greater than 0°C to 75°C or less.

[0136] 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.

[0137] [Production Example] (Production of an aqueous suspension containing P3HA) P3HA aqueous suspension 1: was cultured according to the method described in the examples of International Publication No. 2015 / 146195, and the weight-average molecular weight (Mw) was adjusted and the suspension purified according to the method described in International Publication No. 2004 / 041936 to obtain an aqueous suspension containing 50% by weight of a P3HB3HH composition (P3HB3HH-1: average ratio of 3HB / 3HH = 89.5 mol% / 10.5 mol% in the entire composition, PHB content in the composition is 6.3% by weight) with a solid content of 220,000 in standard polystyrene equivalent Mw as measured by GPC, which contains P3HB3HH and PHB. The obtained aqueous suspension was dried in a hot air dryer at 60°C, and 2 to 5 mg of the resulting dry material was packed into an aluminum pan. A differential scanning calorimetry analyzer was used to melt the dry material by increasing the temperature from 20°C to 190°C at a rate of 10°C / min under a nitrogen stream, and measurements were taken. The P3HB3HH composition ((P3HB3HH-1)) had two melting point peaks at 110°C (Tma) and 160°C (Tmb).

[0138] P3HA aqueous suspension 2: Cultivated according to the method described in the examples of International Publication No. WO2019 / 142845, and adjusted for weight-average molecular weight (Mw) and purified according to the method described in International Publication No. 2004 / 041936, to obtain an aqueous suspension containing 50% by weight of a P3HB3HH composition (P3HB3HH-2: P3HB3HH (average content ratio 3HB / 3HH = 84 mol% / 16 mol%)) with a standard polystyrene equivalent Mw of 200,000 as measured by GPC. The obtained aqueous suspension was dried in a hot air dryer at 60°C, and 2 to 5 mg of the dried product was packed into an aluminum pan. The dried product was melted and measured using a differential scanning calorimetry analyzer under a nitrogen stream, by raising the temperature from 20°C to 190°C at a rate of 10°C / min. The P3HB3HH composition (P3HB3HH-2) did not have Tma, and a melting point peak was observed at 70°C.

[0139] (Method for preparing coating solution) Coating solution 1 was mixed with a P3HA aqueous suspension 1, a water-based coating agent containing a non-water-soluble polyester resin 1 at a solid content concentration of 25% by weight (GX-1483, manufactured by Go-O Chemical Co., Ltd., glass transition temperature (Tg) 70°C, acid value 50-80 mg KOH / g), and water to obtain coating solution 1 with a weight parts ratio of P3HB3HH-1 / polyester resin 1 = 95 / 5 (solid content concentration 40% by weight).

[0140] Coating liquid 2: A water-based coating agent containing a P3HA aqueous suspension 1, a non-water-soluble polyester resin 1 (the aforementioned [GX-1483]), and water was mixed to obtain coating liquid 2 with a weight parts ratio of P3HB3HH-1 / polyester resin 1 = 90 / 10 (solid content concentration 40% by weight).

[0141] Coating liquid 3: A water-based coating agent containing a P3HA aqueous suspension 1, a non-water-soluble polyester resin 1 (the aforementioned [GX-1483]), and water was mixed to obtain a coating liquid 3 with a weight parts ratio of P3HB3HH-1 / polyester resin 1 = 60 / 40 (solid content concentration 35% by weight).

[0142] Coating liquid 4: A water-based coating agent containing a P3HA aqueous suspension 1, a non-water-soluble polyester resin 1 (the aforementioned [GX-1483]), and water was mixed to obtain a coating liquid 4 with a weight parts ratio of P3HB3HH-1 / polyester resin 1 = 40 / 60 (solid content concentration 30% by weight).

[0143] Coating solution 5 was prepared by mixing a P3HA aqueous suspension 1, a water-based coating agent containing a non-water-soluble polyester resin 2 at a solid content concentration of 25% by weight (GX-1471, manufactured by Go-O Chemical Co., Ltd., glass transition temperature (Tg) 48°C, acid value less than 10 mg KOH / g), and water to obtain a coating solution 5 with a weight parts ratio of P3HB3HH-1 / polyester resin 2 = 90 / 10 (solid content concentration 40% by weight).

[0144] Coating solution 6 was obtained by mixing a P3HA aqueous suspension 1, a water-based coating agent containing a non-water-soluble acrylic resin 1 at a solid content concentration of 55% by weight (BASF Japan Ltd. JONCRYL [DFC-3040], glass transition temperature (Tg) 21°C, acid value 55 mg KOH / g), and water, to obtain a coating solution 6 with a weight parts ratio of P3HB3HH-1 / acrylic resin 1 = 60 / 40 (solid content concentration 40% by weight).

[0145] Coating liquid 7: A water-based coating agent containing a P3HA aqueous suspension 1, a water-insoluble acrylic resin 1 (the aforementioned [DFC-3040]), methylcellulose (Shin-Etsu Chemical Co., Ltd. [SM-400]), and water was mixed to obtain a coating liquid 7 with a weight parts ratio of P3HB3HH-1 / acrylic resin 1 / methylcellulose = 59 / 40 / 1 (solid content concentration 40% by weight).

[0146] Coating liquid 8: A water-based coating agent containing a P3HA aqueous suspension 1, a water-insoluble acrylic resin 1 (the aforementioned [DFC-3040]), partially saponified polyvinyl alcohol (Kuraray Co., Ltd. [5-88], degree of saponification 88 mol%), and water were mixed to obtain a coating liquid 8 with a weight parts ratio of P3HB3HH-1 / acrylic resin 1 / partially saponified polyvinyl alcohol = 58 / 40 / 2 (solids content concentration 40% by weight).

[0147] Coating solution 9: A water-based coating agent containing a P3HA aqueous suspension 1, a water-insoluble acrylic resin 2 at a solid content concentration of 38% by weight (SEIKOAT RE-2194, manufactured by Seikoh PMC Co., Ltd., glass transition temperature (Tg) 2°C, acid value 33 mg KOH / g), and water was mixed to obtain a coating solution 9 with a weight parts ratio of P3HB3HH-1 / acrylic resin 2 = 60 / 40 (solid content concentration 40% by weight).

[0148] Coating solution 10: P3HA aqueous suspension 1, water-soluble resin methylcellulose (the aforementioned [SM-400]), and water were mixed to obtain coating solution 10 with a weight parts ratio of P3HB3HH-1 / methylcellulose = 99 / 1 (solid content concentration 40% by weight).

[0149] Coating solution 11: A P3HA aqueous suspension 1, partially saponified polyvinyl alcohol (see [5-88] above) and water were mixed to obtain a coating solution 11 with a weight parts ratio of P3HB3HH-1 / partially saponified polyvinyl alcohol = 90 / 10 (solids concentration 40% by weight).

[0150] Coating solution 12 was obtained by mixing a P3HA aqueous suspension 1, a partially saponified ethylene-vinyl acetate copolymer of a water-soluble resin (Kuraray Co., Ltd. [Exceval RS-1713], degree of saponification 92-94 mol%), and water to obtain a coating solution 12 with a weight parts ratio of P3HB3HH-1 / partially saponified ethylene-vinyl acetate copolymer = 98 / 2 (solids content concentration 40% by weight).

[0151] Coating solution 13: A P3HA aqueous suspension 1, a partially saponified ethylene-vinyl acetate copolymer of a water-soluble resin (the aforementioned [Exceval RS-1713]), and water were mixed to obtain a coating solution 13 with a weight ratio of P3HB3HH-1 / partially saponified ethylene-vinyl acetate copolymer = 90 / 10 (solid content concentration 40% by weight).

[0152] Coating solution 14: A P3HA aqueous suspension 1, a water-soluble resin fully saponified polyvinyl alcohol (manufactured by Kuraray Co., Ltd. [28-98], degree of saponification 98 mol%), and water were mixed to obtain a coating solution 14 with a weight parts ratio of P3HB3HH-1 / fully saponified polyvinyl alcohol = 98 / 2 (solids concentration 40 wt%).

[0153] Coating solution 15 was mixed with P3HA aqueous suspension 1, water-soluble resin fully saponified polyvinyl alcohol (see [28-98] above), and water to obtain coating solution 15 with a weight parts ratio of P3HB3HH-1 / fully saponified polyvinyl alcohol = 90 / 10 (solids content concentration 30% by weight).

[0154] Coating solution 16: P3HA aqueous suspension 1, water-soluble resin fully saponified polyvinyl alcohol (see [28-98] above), and water were mixed to obtain coating solution 16 with a weight parts ratio of P3HB3HH-1 / fully saponified polyvinyl alcohol = 60 / 40 (solids content concentration 16% by weight).

[0155] Coating solution 17 was obtained by mixing a P3HA aqueous suspension 1, an aqueous coating agent containing a non-water-soluble acrylic resin 3 at a solid content concentration of 40% by weight (SEIKOAT PE-2273, manufactured by Seikoh PMC Co., Ltd., glass transition temperature (Tg) -11°C, acid value 38 mg KOH / g), and water, with a weight parts ratio of P3HB3HH-1 / acrylic resin 3 = 60 / 40 (solid content concentration 40% by weight).

[0156] Coating liquid 18: A water-based coating agent containing a P3HA aqueous suspension 2, a non-water-soluble polyester resin 2 (the aforementioned [GX-1471]), and water was mixed to obtain a coating liquid 18 with a weight parts ratio of P3HB3HH-2 / polyester resin 2 = 90 / 10 (solid content concentration 40% by weight).

[0157] (Production of P3HA-based resin pellets) P3HA-based resin pellets were produced using the following P3HA powders: A-1: ​​Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) obtained according to the method described in Example 9 of International Publication No. 2019 / 142845, with a 3-hydroxyhexanoate (3HH) composition of 26.3 mol% and a standard polystyrene equivalent Mw of 360,000 as measured by GPC. A-2: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) obtained according to the method described in Example 2 of International Publication No. 2019 / 142845, with a 3HH composition of 2.1 mol% and a standard polystyrene equivalent Mw of 360,000 as measured by GPC. A-3: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) obtained according to the method described in Example 1 of International Publication No. 2019 / 142845, having a 3-hydroxyhexanoate (3HH) composition of 6.0 mol% and a standard polystyrene equivalent Mw of 220,000 as measured by GPC.

[0158] As P3HA, A-1 (24 parts by weight) and A-2 (16 parts by weight), as well as the organic peroxide tributylperoxyisopropyl monocarbonate (manufactured by NOF Corporation: Perbutyl I, half-life temperature at 1 minute: 158.8°C, 0.105 parts by weight), plasticizer (manufactured by Riken Vitamin Co., Ltd.: BIOCIZER, 0.42 parts by weight), pentaerythritol (manufactured by Mitsubishi Chemical Corporation: Neurizer P, 1.0 part by weight), and behenamide (manufactured by Nippon Seika Co., Ltd.: BNT-22H, 0.5 parts by weight) were fed from the main feeder, and A-3 (60 parts by weight) was fed from the side feeder into a co-meshing twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.: TEM26SS (L / D=60)), and melt mixing was carried out at a barrel temperature of 140-160°C, a screw rotation speed of 100 rpm, and a discharge rate of 10 kg / hr. In this process, P3HA (A-1 and A-2) introduced from the main feeder is the reaction product with organic peroxides. The strand obtained from the die was passed through a water tank filled with 40-45°C to solidify, and then cut with a pelletizer to obtain P3HA-based resin pellets as P3HB3HH-3.

[0159] (Balance of the resin layer) Each coated paper was cut into 10cm x 10cm pieces, and its weight was measured. The weight of the base paper was subtracted from this value, and the result was multiplied by 100 to obtain the basis weight of the resin.

[0160] (Example 1) Basis weight 64 g / m ２ On one side (referred to as side A) of a sheet of high-quality A4 paper, dry weight 10 g / m² ２ After applying coating liquid 1 using a bar coater, the material was heated in a hot air drying oven set to 100°C for 3 minutes to form a resin layer (B) and obtain a laminate.

[0161] (Example 2) A laminate was obtained by following the same procedure as in Example 1, except that a resin layer (B) was formed using coating liquid 2.

[0162] (Example 3) A laminate was obtained by performing the same procedure as in Example 1, except that a resin layer (B) was formed using coating liquid 3.

[0163] (Example 4) A laminate was obtained by following the same procedure as in Example 1, except that a resin layer (B) was formed using coating liquid 4.

[0164] (Example 5) A laminate was obtained by performing the same procedure as in Example 1, except that a resin layer (B) was formed using coating liquid 5.

[0165] (Example 6) Basis weight 64 g / m ２ On one side (referred to as side A) of a sheet of high-quality A4 paper, dry weight 5g / m² ２ After applying coating liquid 5 using a bar coater, the resin layer (B) was formed by heating in a hot air drying oven set to 100°C for 3 minutes. Then, the opposite side of the paper (referred to as side B) was similarly coated with a dry weight of 5 g / m². ２ A resin layer (B) was formed, and a laminate was obtained.

[0166] (Example 7) Using coating liquid 6, the dry weight of the resin layer (B) was 5 g / m². ２ Except for the above, the procedure was the same as in the method described in Example 1 to obtain a laminate.

[0167] (Example 8) A laminate was obtained by following the same procedure as in Example 1, except that a resin layer (B) was formed using coating liquid 6.

[0168] (Example 9) Using coating liquid 6, the dry weight of the resin layer (B) was set to 20 g / m². ２ Except for the above, the procedure was the same as in the method described in Example 1 to obtain a laminate.

[0169] (Example 10) A laminate was obtained by following the same procedure as in Example 1, except that a resin layer (B) was formed using coating liquid 7.

[0170] (Example 11) A laminate was obtained by following the same procedure as in Example 1, except that a resin layer (B) was formed using coating liquid 8.

[0171] (Example 12) A laminate was obtained by following the same procedure as in Example 1, except that a resin layer (B) was formed using coating liquid 9.

[0172] (Example 13) Basis weight 64 g / m ２ On one side (referred to as side A) of a sheet of high-quality A4 paper, dry weight 5g / m² ２After applying coating liquid 5 using a bar coater, the resin layer (B) was formed by heating in a hot air drying oven set to 100°C for 3 minutes. Subsequently, the P3HA resin pellets were fed into a single-screw extruder equipped with a T-type die, and extruded from the T-type die under conditions that the resin temperature immediately after extrusion was 163°C. Using a cooling roll set to 40°C, the resin layer (B) of the high-quality paper with the resin layer (B) prepared above was then applied to the resin layer (B) with a basis weight of 25 g / m². ２ A resin layer (C) was formed by lamination, and a laminate was obtained.

[0173] (Example 14) Using coating solution 5, the procedure was carried out in the same manner as in Example 6, with a basis weight of 64 g / m². ２ High-quality A4 size paper, both sides, dry weight 5g / m² ２ A resin layer (B) was formed. Next, the P3HA resin pellets were fed into a single-screw extruder equipped with a T-type die, and extruded from the T-type die under conditions that the resin temperature immediately after extrusion was 163°C. Using a cooling roll set to 40°C, the resin was then applied to one side of the high-quality paper with the resin layer (B) prepared above, with a basis weight of 25 g / m². ２ A resin layer (C) was formed by lamination, and a laminate was obtained.

[0174] (Example 15) Using coating solution 5, the procedure was carried out in the same manner as in Example 6, with a basis weight of 64 g / m². ２ High-quality A4 size paper, both sides, dry weight 5g / m² ２ A resin layer (B) was formed. Next, the P3HA resin pellets were fed into a single-screw extruder equipped with a T-type die, and extruded from the T-type die under conditions that the resin temperature immediately after extrusion was 163°C. Using a cooling roll set to 40°C, the resin was applied to both sides of the high-quality paper with the resin layer (B) prepared above, one side at a time, with a basis weight of 25 g / m². ２ A resin layer (C) was formed by lamination, and a laminate was obtained.

[0175] (Example 16) A laminate was obtained by following the same procedure as in Example 1, except that a resin layer (B) was formed using the coating liquid 17.

[0176] (Comparative Example 1) Using coating liquid 10, the dry weight of the resin layer (B) was 20 g / m². ２ Except for the above, the procedure was the same as in the method described in Example 1 to obtain a laminate.

[0177] (Comparative Example 2) A laminate was obtained by the same procedure as in Example 1, except that a resin layer (B) was formed using the coating liquid 11.

[0178] (Comparative Example 3) A laminate was obtained by the same procedure as in Example 1, except that a resin layer (B) was formed using the coating liquid 12.

[0179] (Comparative Example 4) Using coating solution 12, the dry weight of the resin layer (B) was 20 g / m². ２ Except for the above, the procedure was the same as in the method described in Example 1 to obtain a laminate.

[0180] (Comparative Example 5) Using coating solution 13, the dry weight of the resin layer (B) was 20 g / m². ２ Except for the above, the procedure was the same as in the method described in Example 1 to obtain a laminate.

[0181] (Comparative Example 6) A laminate was obtained by the same procedure as in Example 1, except that a resin layer (B) was formed using the coating liquid 14.

[0182] (Comparative Example 7) A laminate was obtained by the same procedure as in Example 1, except that a resin layer (B) was formed using the coating liquid 15.

[0183] (Comparative Example 8) A laminate was obtained by the same procedure as in Example 1, except that a resin layer (B) was formed using the coating liquid 16.

[0184] (Comparative Example 9) The procedure was the same as in Comparative Example 4, except that the coating liquid 12 was applied to the paper and then heated in a hot air drying oven set to 160°C for 3 minutes to obtain a laminate.

[0185] (Comparative Example 10) A laminate was obtained by the same procedure as in Example 1, except that a resin layer (B) was formed using the coating liquid 18.

[0186] The blocking resistance and water resistance of the resin layer of the laminates obtained in the examples and comparative examples were evaluated by the method described below. The results are shown in Tables 1 and 2.

[0187] (Evaluation of the blocking resistance of the resin layer) Evaluation method 1: Basis weight 64 g / m ２ On A4-sized high-quality paper, the coating solution was applied under the conditions described in the Examples and Comparative Examples. After heating in a hot air drying oven set to 100°C for 3 minutes, a resin layer (B) was formed. Immediately after removing the laminate from the drying oven, it was folded and the resin layers (B) were stacked on top of each other to evaluate whether the resin layers (B) were tacky. <Evaluation> ○: Not tacky ×: Tacky A rating of ○ in this evaluation method 1 indicates that blocking is unlikely to occur even when the resin layers are stacked on top of each other immediately after the laminate is manufactured.

[0188] Evaluation Method 2: Cut the laminate to a width of 25 mm and a length of 100 mm (with the direction in which the coating liquid was applied with a bar coater and the direction in which the P3HA resin pellets were extruded as the longitudinal side). Place the resin layer of the laminate on top of high-quality paper that does not have a resin layer formed on top of the laminate, and use a heat sealer (TP-701-B, manufactured by Tester Sangyo Co., Ltd.) with the heating plate set to 70°C and surface pressure of 10 kgf / cm². ２ The structures were pressed together under the condition of a sealing time of 5 minutes, and a structure including a heat-sealed area was obtained. The size of the heat-sealed area was 20 mm (width of the heating plate) x 25 mm (width of the test piece). The heat-sealed portion of the obtained structure was peeled off by hand, and the condition of the peeled surface was visually checked and evaluated according to the following criteria. The resin layer used in the evaluation was resin layer (B) in Examples 1 to 12, 16 and each comparative example, and resin layer (C) formed by lamination in Examples 13 to 15. <Evaluation> ○: No paper breakage occurs, and the heat-sealed resin layer peels off without resistance at the interface between the resin layer and the paper. ×: Material breakage of the paper occurs. This evaluation method 2 simulates the conditions under which the resin layer and the substrate are in close contact at high temperatures during storage or transportation of the laminate. The fact that the resin layer and paper peeled off easily under these conditions indicates that blocking is unlikely to occur during storage or transportation of the laminate. On the other hand, the occurrence of material breakage of the paper means that blocking is likely to occur.

[0189] Overall evaluation of blocking resistance: Blocking resistance was comprehensively evaluated based on the results of evaluation method 1 and evaluation method 2, according to the following criteria. ○: Good evaluation results in both evaluation method 1 and evaluation method 2. △: Good results in evaluation method 1 regarding blocking resistance immediately after manufacturing of the laminate, but poor results in evaluation method 2 regarding blocking resistance during storage and transportation of the laminate. ×: Poor results in evaluation method 1 regarding blocking resistance immediately after manufacturing of the laminate.

[0190] (Evaluation of the water resistance of the resin layer) A laminate cut into 25 mm squares was immersed in 50 mL of water in a glass bottle, and the glass bottle was placed in an ultrasonic cleaner (VS-100III manufactured by Velvoclear Co., Ltd.) and ultrasonic waves were applied at 28 Hz for 1 minute. The peeling of the resin layer was visually confirmed and evaluated according to the following criteria. <Evaluation> ◎: No peeling of the resin layer was observed, and the water remained clear. ○: Some peeling of the resin layer was observed, but the water remained clear. △: The resin layer peeled off and settled, and the water became slightly cloudy. ×: The resin layer peeled off, and the water became significantly cloudy. If the evaluation result is ◎ or ○, it can be said that the resin layer has sufficient water resistance.

[0191]

[0192]

[0193] <Results> As can be seen from Table 1, in each example in which a resin layer (B) containing a poly(3-hydrocyalkanoate) resin (b1) and a water-insoluble resin (b2) was formed on a substrate layer (A), the water resistance and blocking resistance of the resin layer were good. However, in Example 16, as a water-insoluble resin (b2) with a low glass transition temperature of 0°C or less was used, the blocking resistance in evaluation method 2 was insufficient, but the blocking resistance in evaluation method 1 was good.

[0194] In contrast, Table 2 shows that in Comparative Examples 1 to 8, where a water-soluble resin was used instead of a water-insoluble resin (b2), the water resistance was insufficient, and peeling of the resin layer occurred when in contact with water.

[0195] In Comparative Example 9, as in Comparative Example 4, water resistance was improved by increasing the heating temperature to 160°C when forming the resin layer (B) after applying a coating solution containing a water-soluble resin. However, the crystallization of the resin layer immediately after heating was insufficient, resulting in a sticky resin layer and a deterioration in the blocking resistance in Evaluation Method 1.

[0196] In Comparative Example 10, instead of the poly(3-hydrocyalkanoate) resin (b1), a poly(3-hydrocyalkanoate) resin that does not have a melting peak top temperature in the range of 100 to 150°C was used, and as a result, the blocking resistance was insufficient in both evaluation methods 1 and 2.

Claims

1. A laminate comprising a base layer (A) and a resin layer (B) provided on at least one surface of the base layer, wherein the resin layer (B) contains a poly(3-hydroxyalkanoate) resin (b1) and a water-insoluble resin other than resin (b2), and the poly(3-hydroxyalkanoate) resin (b1) has at least one peak-top temperature (Tma) in the range of 100 to 150°C in the crystal melting curve obtained by differential scanning calorimetry.

2. The laminate according to claim 1, wherein the non-water-soluble resin (b2) has a glass transition temperature greater than 0°C and 75°C or less.

3. The laminate according to claim 1 or 2, wherein the dry weight ratio of the poly(3-hydroxyalkanoate) resin (b1) to the water-insoluble resin (b2) is 30:70 to 90:

10.

4. The laminate according to claim 1 or 2, wherein the water-insoluble resin (b2) is at least one selected from the group consisting of acrylic resins and polyester resins.

5. The laminate according to claim 1 or 2, wherein the poly(3-hydroxyalkanoate) resin (b1) comprises a copolymer (b1-1) of a 3-hydroxybutyrate unit and another hydroxyalkanoate unit.

6. The laminate according to claim 5, wherein the content of the other hydroxyalkanoate units in the copolymer (b1-1) is 4 to 12 mol%.

7. The laminate according to claim 1 or 2, wherein the poly(3-hydroxyalkanoate) resin (b1) further has at least one peak top temperature (Tmb) in the range of 150 to 170°C in the crystal melting curve obtained by differential scanning calorimetry, and the temperature difference between Tma and Tmb is 10°C or more.

8. The laminate according to claim 1 or 2, further comprising a resin layer (C) containing a poly(3-hydroxyalkanoate) resin (c1) laminated on the resin layer (B).

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

10. A method for manufacturing a laminate, comprising the steps of applying an aqueous dispersion containing a poly(3-hydroxyalkanoate) resin (b1) having at least one peak top temperature (Tma) in the range of 100 to 150°C in the crystal melting curve obtained by differential scanning calorimetry, and a water-insoluble resin (b2) other than resin (b1) to at least one surface of a base layer (A), and heating and drying at 95 to 120°C to form a resin layer (B) on the base layer (A).

11. The method for manufacturing a laminate according to claim 10, wherein the non-water-soluble resin (b2) has a glass transition temperature greater than 0°C and 75°C or less.

12. A method for producing a laminate according to claim 10 or 11, further comprising the step of forming a resin layer (C) containing a poly(3-hydroxyalkanoate) resin (c1) on the resin layer (B).

13. An aqueous dispersion comprising a poly(3-hydroxyalkanoate) resin (b1) and a water-insoluble resin other than resin (b2) dispersed in water, wherein the poly(3-hydroxyalkanoate) resin (b1) has at least one peak-top temperature (Tma) in the range of 100 to 150°C in the crystal melting curve obtained by differential scanning calorimetry.

14. The method for manufacturing a laminate according to claim 13, wherein the non-water-soluble resin (b2) has a glass transition temperature greater than 0°C and 75°C or less.

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