Resin sheets and molded articles

Abstract

To provide resin sheets with excellent thermoforming properties. [Solution] A poly(3-hydroxyalkanoate) resin (A), crosslinked resin particles (B) containing the polyhydroxyalkanoate resin and having a gel fraction of 50% or more, and an inorganic filler (C) are included. A resin sheet wherein, per 100 parts by weight of the total amount of the poly(3-hydroxyalkanoate) resin (A) and the crosslinked resin particles (B), the content of the poly(3-hydroxyalkanoate) resin (A) is 88.0 parts by weight to 99.5 parts by weight, the content of the crosslinked resin particles (B) is 0.5 parts by weight to 12.0 parts by weight, and the content of the inorganic filler (C) is 1.0 part by weight to 15.0 parts by weight.

Description

Technical Field

[0001] The present invention relates to a resin sheet and a molded body.

Background Art

[0002] Plastic waste causes a burden on the global environment, such as its impact on the ecosystem, generation of harmful gases during combustion, and global warming due to a large amount of combustion heat. As a material that can solve this problem, the development of biodegradable plastics has been actively carried out.

[0003] For example, Patent Document 1 discloses a biodegradable resin composition containing a biodegradable resin (A) and an inorganic filler (B) having a median diameter of 10 μm or less.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the above-mentioned conventional technologies are not sufficient from the viewpoint of thermoforming processability, and there is room for further improvement.

[0006] One embodiment of the present invention has been made in view of the above situation, and its object is to provide a resin sheet having excellent thermoforming processability.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the above problems, the inventors of the present invention have completed one embodiment of the present invention. That is, one embodiment of the present invention includes the following configurations. [1] A resin sheet comprising a poly(3-hydroxyalkanoate) resin (A), crosslinked resin particles (B) containing the polyhydroxyalkanoate resin and having a gel fraction of 50% or more, and an inorganic filler (C), A resin sheet wherein, per 100 parts by weight of the total amount of the poly(3-hydroxyalkanoate) resin (A) and the crosslinked resin particles (B), the content of the poly(3-hydroxyalkanoate) resin (A) is 88.0 parts by weight to 99.5 parts by weight, the content of the crosslinked resin particles (B) is 0.5 parts by weight to 12.0 parts by weight, and the content of the inorganic filler (C) is 1.0 part by weight to 15.0 parts by weight. [2] The resin sheet according to [1], wherein the drawdown time of the resin sheet is 45 seconds or more. (Here, the drawdown time is the time from the start of heating until the vertical distance from the lowest point of the resin sheet to the bottom surface of the resin sheet when it is fixed to the frame reaches 7 cm, when the resin sheet is heated to 400°C while sandwiched and fixed in the frame.) [3] The resin sheet according to [1] or [2], wherein the poly(3-hydroxyalkanoate) resin (A) includes a poly(3-hydroxybutyrate) resin. [4] The resin sheet according to [3], wherein the poly(3-hydroxybutyrate) resin comprises a copolymer containing 3-hydroxybutyrate units and other hydroxyalkate units. [5] The resin sheet according to [4], wherein the copolymer containing the 3-hydroxybutyrate unit and other hydroxyalkate units is a mixture of two or more copolymers with different content of the 3-hydroxybutyrate unit. [6] The resin sheet according to any one of [1] to [5], wherein the inorganic filler (C) is a layered clay mineral. [7] The resin sheet according to any one of [1] to [6], wherein the inorganic filler (C) is one or more selected from the group consisting of mica, talc, kaolinite, and calcium carbonate. A molded body made by molding a resin sheet as described in any one of [8], [1], to [7]. [9] The molded body described in [8], which is a vacuum-formed body. [Effects of the Invention]

[0008] According to one embodiment of the present invention, a resin sheet with excellent thermoformability can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram illustrating the method for evaluating drawdown time in the example. [Modes for carrying out the invention]

[0010] One embodiment of the present invention is described below, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications are possible within the scope of the claims. Furthermore, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Moreover, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic and patent documents mentioned herein are incorporated herein by reference. Furthermore, unless otherwise specified herein, "A to B" representing a numerical range means "A or greater (including A and greater than A) and B or less (including B and less than B)."

[0011] [1. Resin sheet] A resin sheet according to one embodiment of the present invention is a resin sheet comprising a poly(3-hydroxyalkanoate) resin (A), crosslinked resin particles (B) containing a polyhydroxyalkanoate resin and having a gel fraction of 50% or more, and an inorganic filler (C), wherein the content of the poly(3-hydroxyalkanoate) resin (A) is 88.0 parts by weight to 99.5 parts by weight, the content of the crosslinked resin particles (B) is 0.5 parts by weight to 12.0 parts by weight, and the content of the inorganic filler (C) is 1.0 part by weight to 15.0 parts by weight, based on 100 parts by weight of the total amount of the poly(3-hydroxyalkanoate) resin (A) and the crosslinked resin particles (B).

[0012] In this specification, "a resin sheet according to one embodiment of the present invention" may be referred to as "the present resin sheet." The crosslinked resin particles (B) contained in the present resin sheet may also be referred to as the crosslinked resin particles (B) according to one embodiment of the present invention. In this specification, "a crosslinked resin particle (B) according to one embodiment of the present invention" may be referred to as "the present crosslinked resin particles (B)." In this specification, "poly(3-hydroxyalkanoate) resin (A)" may be referred to as "resin (A)."

[0013] As described above, the conventional technology was insufficient from the standpoint of thermoformability and there was room for further improvement. Molded articles obtained by molding resin sheets with poor thermoformability were inferior in one or more of the group consisting of perforations, wrinkles, and bridges. In other words, molded articles obtained by molding resin sheets obtained by the conventional technology were inferior in one or more of the group consisting of perforations, wrinkles, and bridges.

[0014] Therefore, the present inventor has conducted intensive studies to provide a resin sheet excellent in thermoformability, more specifically, a resin sheet capable of providing a molded body in which all of the holes, wrinkles, and bridges are at a level above the passing standard. As a result, the present inventor has independently found the following new findings and has completed the present invention: A resin sheet containing a poly(3-hydroxyalkanoate) resin, a predetermined amount of crosslinked resin particles, and a predetermined amount of inorganic filler can surprisingly provide a molded body excellent in thermoformability and in which all of the holes, wrinkles, and bridges are at a level above the passing standard.

[0015] In a conventional resin sheet, it is known that the impact strength of the resin sheet is improved by containing crosslinked resin particles. Also, in a conventional resin sheet, it is known that the rigidity of the resin sheet is improved by containing an inorganic filler. That is, in a conventional resin sheet, crosslinked resin particles and an inorganic filler are contained to improve the mechanical strength such as the impact strength and rigidity of the resin sheet.

[0016] On the other hand, in one embodiment of the present invention, as described above, in order to provide a resin sheet excellent in thermoformability, a predetermined amount of crosslinked resin particles and a predetermined amount of inorganic filler are used in combination with a poly(3-hydroxyalkanoate) resin. The fact that a resin sheet excellent in thermoformability can be provided by the combined use of a poly(3-hydroxyalkanoate) resin, a predetermined amount of crosslinked resin particles, and a predetermined amount of inorganic filler is a finding first discovered by the present inventor. That is, one embodiment of the present invention cannot be easily conceived from the prior art and conventional knowledge.

[0017] Because this resin sheet has the above-described structure, it has the advantage of excellent thermoformability. More specifically, this resin sheet has the advantage of being able to provide molded articles in which perforation, wrinkles, and bridging are all at an acceptable level or higher. "Thermoformability" can also be called "thermal properties of the resin during molding." Here, the following reasons are presumed to be the reason why this resin sheet has excellent thermoformability due to containing a predetermined amount of crosslinked resin particles and a predetermined amount of inorganic filler. This resin sheet is thought to possess strain-curing properties due to the presence of a predetermined amount of crosslinked resin particles (B). Due to its strain-curing properties, when the resin sheet is heated, the viscosity of the constituent resin increases in areas with low thickness, suppressing deformation. On the other hand, deformation progresses in areas with higher thickness surrounding the low-thickness areas, i.e., areas where the viscosity of the constituent resin is not high. As a result, the thermal deformation of the resin sheet becomes uniform, improving its moldability, and consequently, it is presumed to have excellent thermoformability. In one embodiment of the present invention, the crosslinked resin particles (B) may contain a large amount of soft components, but even in that case, it is thought that the resin sheet contains a predetermined amount of inorganic filler (C), which reduces or prevents the decrease in dimensional stability during thermoforming caused by these soft components. As a result, the resin sheet is given dimensional stability during thermoforming, and it is presumed that this also contributes to the resin sheet having excellent thermoformability. One embodiment of the present invention is not limited in any way to such speculation.

[0018] In one embodiment of the present invention, the thermoformability of the resin sheet is evaluated by the presence of holes, wrinkles, and bridges in the molded body formed by molding the resin sheet. The evaluation methods for the presence of holes, wrinkles, and bridges in the molded body will be described in detail in the examples below. In other words, in this specification, a "resin sheet with excellent thermoformability" refers to a resin sheet in which the presence of holes, wrinkles, and bridges in the molded body evaluated by the method described in detail in the examples below are all at a level above passing. In this specification, when it is stated that "the resin sheet has excellent thermoformability", it is intended that the presence of holes, wrinkles, and bridges in the molded body formed by molding the resin sheet are all at a level above passing.

[0019] In a preferred embodiment of the present invention, the resin sheet also has the advantage of excellent appearance. "Excellent appearance" can also be said to be "beautiful appearance". The evaluation method for the appearance of the resin sheet will be described in detail in the examples below.

[0020] Each member constituting the present resin sheet will be described in detail below. First, the crosslinked resin particles (B) will be described in detail.

[0021] <Crosslinked resin particles (B)> The crosslinked resin particles (B), that is, the present crosslinked resin particles (B), contain a polyhydroxyalkanoate-based resin and have a gel fraction of 50% or more. In this specification, the "polyhydroxyalkanoate-based resin" may be referred to as "PHA". In addition to a predetermined amount of the present crosslinked resin particles (B), the present resin sheet contains a predetermined amount of an inorganic filler (C) described later, and thus has the advantage of excellent thermoformability. In other words, by using a combination of a predetermined amount of the present crosslinked resin particles (B) and the predetermined amount of the inorganic filler (C), the thermoformability of the resin sheet, that is, the resin thermal characteristics during molding can be improved. Further, in addition to a predetermined amount of the present crosslinked resin particles (B), the present resin sheet contains a predetermined amount of an inorganic filler (C) described later, and thus also has the advantage of excellent appearance.

[0022] (PHA) "PHA" is a general term for polymers containing hydroxyalkanoic acid as monomer units (monomer repeating units), and is generally biodegradable. PHA is an aliphatic polyester, preferably a polyester that does not contain aromatic rings. In this specification, "PHA" means a polymer that contains 50 mol% or more of hydroxyalkanoic acid repeating units out of the total monomer repeating units (100 mol%). PHA preferably contains 60 mol% or more of hydroxyalkanoic acid repeating units out of the total monomer repeating units (100 mol%), and more preferably 70 mol% or more.

[0023] The PHA is not particularly limited. Examples of PHA include polyglycolic acid, poly(3-hydroxyalkanoate) resins (hereinafter sometimes referred to as "P3HA"), and poly(4-hydroxyalkanoate) resins. One type of PHA may be used alone, or two or more types may be used in combination. The PHA preferably contains a poly(3-hydroxyalkanoate) resin, and more preferably is a poly(3-hydroxyalkanoate) resin (in other words, is composed solely of a poly(3-hydroxyalkanoate) resin).

[0024] In this specification, "polyglycolic acid" refers to a resin containing 50 mol% or more of the repeating units represented by [-CH2-CO-O-] out of the total monomer repeating units (100 mol%). Polyglycolic acid may contain 60 mol% or more, 70 mol% or more, 80 mol% or more, or 90 mol% or more of the repeating units represented by [-CH2-CO-O-] out of the total monomer repeating units (100 mol%).

[0025] Polyglycolic acid may be a homopolymer of glycolic acid, or it may be a copolymer of glycolic acid with a monomer other than glycolic acid (for example, a copolymer of glycolic acid and lactic acid, or a copolymer of glycolic acid and caprolactone).

[0026] Polyglycolic acid can be obtained by known methods such as the condensation polymerization of glycolic acid and the ring-opening polymerization of glycolide.

[0027] The aforementioned P3HA is a 3-hydroxyalkanoic acid repeating unit represented by the formula: [-CHR-CH2-CO-O-] (wherein R is C n H 2n+1 The alkyl group represented by , where n is an integer between 1 and 15, is a polyhydroxyalkanoate containing ) as an essential repeating unit. In this specification, "P3HA" refers to a resin containing 50 mol% or more of the 3-hydroxyalkanoic acid repeating unit out of the total monomer repeating units (100 mol%). The P3HA preferably contains 60 mol% or more of the 3-hydroxyalkanoic acid repeating unit out of the total monomer repeating units (100 mol%), and more preferably 70 mol% or more.

[0028] P3HA is not particularly limited and may be a homopolymer containing the aforementioned repeating units or a copolymer containing the aforementioned repeating units. Examples of the copolymer include a copolymer of 3-hydroxybutanoic acid (hereinafter sometimes referred to as "3HB") and one or more monomers selected from the group consisting of 3-hydroxypropionic acid, 3-hydroxypentanoic acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxynonanoic acid, 3-hydroxydecanoic acid, 3-hydroxyundecanoic acid, 3-hydroxydodecanoic acid, 3-hydroxytridecanoic acid, 3-hydroxytetradecanoic acid, 3-hydroxyhexadecanoic acid, and 3-hydroxyoctadecanoic acid. Alternatively, other examples of the copolymer include copolymers of 3HB with one or more monomers selected from the group consisting of 4-hydroxybutanoic acid, 4-hydroxypentanoic acid, 4-hydroxyhexanoic acid, 4-hydroxyheptanoic acid, 4-hydroxyoctanoic acid, 4-hydroxynonanoic acid, 4-hydroxydecanoic acid, 4-hydroxyundecanoic acid, 4-hydroxydodecanoic acid, 4-hydroxytridecanoic acid, 4-hydroxytetradecanoic acid, 4-hydroxyhexadecanoic acid, and 4-hydroxyoctadecanoic acid.

[0029] Examples of P3HA include poly(3-hydroxybutyrate) (hereinafter sometimes referred to as "P3HB"), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (hereinafter sometimes referred to as "P3HB3HH"), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (hereinafter sometimes referred to as "P3HB4HB"), which are homopolymers of 3HB. Only one type of P3HA may be used, or two or more types may be used in combination. In this specification, "poly(X-co-Y)" refers to a copolymer containing X repeating units and Y repeating units, and is intended to be a copolymer obtained by copolymerizing the monomer from which the X repeating unit is derived and the monomer from which the Y repeating unit is derived. In addition, during the production of P3HA by microorganisms, trace amounts (about 1 mol% or less) of monomers may be copolymerized, but if this does not significantly affect the physical properties of the obtained P3HA, those monomers will be considered not to have been copolymerized, and the product will be referred to by a name that does not include those monomers.

[0030] P3HA can be produced by microorganisms. Such microbially produced P3HA is usually composed only of D-isomer (R-isomer) 3-hydroxyalkanoic acid repeating units. Among microbially produced P3HAs, P3HB, P3HB3HH, and P3HB4HB are preferred, and P3HB3HH and P3HB4HB are more preferred, due to their ease of industrial production.

[0031] It is also preferable that the P3HA contains 3-hydroxybutanoic acid (3HB) repeating units. When the P3HA contains 3HB repeating units, the composition ratio of 3HB repeating units in the P3HA is preferably 60 mol% to 99 mol%, more preferably 61 mol% to 97 mol%, and even more preferably 62 mol% to 95 mol% of the total monomer repeating units (100 mol%). This configuration has the advantage that the resin sheet has superior thermoformability. The monomer composition ratio of P3HA can be measured by gas chromatography or the like (see, for example, International Publication No. 2014 / 020838). Two or more types of P3HA with different composition ratios of 3HB repeating units may be used in combination.

[0032] The microorganisms that produce P3HA are not particularly limited as long as they are capable of producing P3HA. For example, the first P3HB-producing bacterium was Bacillus megaterium, discovered in 1925, and other known natural microorganisms include Cupriavidus necator (formerly classified as Alcaligenes eutrophus and Ralstonia eutropha) and Alcaligenes latus. In these microorganisms, P3HB accumulates within the bacterial cells.

[0033] Furthermore, known microorganisms that produce copolymers of 3HB with other hydroxyalkanoates include Aeromonas caviae, which produces P3HB3HH, and Alcaligenes eutrophus, which produces poly(3-hydroxybutyrate-co-4-hydroxybutyrate). In particular, Alcaligenes eutrophus AC32 (FERM BP-6038) (T.Fukui, Y.Doi, J.Bacteriol., 179, p4821-4830 (1997)), into which genes for P3HA synthases have been introduced, is preferred in order to increase the productivity of P3HB3HH. Microbial cells that have accumulated P3HA in their cells by culturing such microorganisms under appropriate conditions are used. In addition to the above, genetically modified microorganisms into which various P3HA synthesis-related genes have been introduced can be used to produce the desired P3HA, or the culture conditions, including the type of substrate, can be optimized.

[0034] The weight-average molecular weight of PHA is not particularly limited. Preferably, the weight-average molecular weight of PHA is 50,000 to 3,000,000, preferably 100,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When the weight-average molecular weight of PHA is 50,000 or higher, it has the advantage of reducing or avoiding the tendency for the cross-linked resin particles (B) to have low strength. Alternatively, when the weight-average molecular weight of PHA is 50,000 or higher, it has the advantage of reducing or avoiding the tendency for stickiness due to low molecular weight components. On the other hand, PHA with a weight-average molecular weight of 3,000,000 or less may have the advantage of being easy to manufacture and / or easy to handle in order to achieve the objectives of one embodiment of the present invention. The numerical values ​​for the weight-average molecular weight of PHA are values ​​obtained by measuring PHA before the cross-linking treatment.

[0035] The weight-average molecular weight can be measured using gel permeation chromatography (GPC) (Shimadzu Corporation's "High-Performance Liquid Chromatograph 20A System"), with a polystyrene gel column (Showa Denko Corporation's "KG 4A", "K-806M", etc.) and chloroform as the mobile phase. The weight-average molecular weight can be determined as the molecular weight in polystyrene terms using a calibration curve obtained by measuring polystyrene with a known molecular weight using the same measurement method. In this case, the calibration curve can be prepared using polystyrene with weight-average molecular weights of 31,400, 197,000, 668,000, and 1,920,000. For the GPC, any column suitable for measuring the molecular weight should be used.

[0036] (Gel fraction) In this specification, "crosslinked resin particles" refers to particles having a crosslinked structure in which the molecular chains of the resin constituting the resin particles are bonded together intramolecularly and / or intermolecularly. That is, the crosslinked resin particles (B) may have a crosslinked structure in which the molecular chains of PHA are bonded together. The amount of crosslinked structure in the crosslinked resin particles (B) affects the gel fraction of the crosslinked resin particles (B), and specifically, the more crosslinked structure there is, the higher the gel fraction. Since the crosslinked resin particles (B) have a certain amount or more of crosslinked structure, they exhibit a high gel fraction, specifically a gel fraction of 50% or more. Because the gel fraction of the crosslinked resin particles (B) is 50% or more, the crosslinked resin particles (B) have excellent hardness, heat resistance and solvent resistance.

[0037] The gel fraction is preferably 60% or more, more preferably 70% or more, even more preferably 75% or more, and particularly preferably 80% or more. It may also be 85% or more, or 90% or more. The upper limit of the gel fraction is not particularly limited and may be 100% or less. From the viewpoint of the production efficiency of the crosslinked resin particles (B), the upper limit of the gel fraction is preferably 99.5% or less, and more preferably 99% or less. It may also be 98% or less, 97% or less, or 96% or less.

[0038] The gel fraction is measured as follows: (1) Add the dried cross-linked resin particles (B) to chloroform to a concentration of 0.7% by weight, and hold the resulting mixture at 60°C for 30 minutes to obtain a chloroform solution; (2) After that, the chloroform solution is left to stand at room temperature for 3 hours, and then filtered through a membrane filter with a pore size of 0.45 μm; (3) Dry the gel remaining on the filter, measure the weight of the dried gel together with the filter, and calculate the gel fraction using the following formula. Formula: Gel fraction (%) = {(Weight of filter containing dry gel - Weight of filter only) / Weight of dry cross-linked resin particles (B) used for measurement} × 100.

[0039] (Volume-average particle size) The volume-average particle diameter of the cross-linked resin particles (B) is preferably 0.10 μm to 10.00 μm. This configuration makes it possible to suitably use the cross-linked resin particles (B) for various applications as described later. From the viewpoint of practical use, the lower limit of the volume-average particle diameter is more preferably 0.15 μm or more, and even more preferably 0.20 μm or more. Furthermore, from the viewpoint of productivity (production of PHA and / or cross-linking treatment, etc.), the upper limit of the volume-average particle diameter is more preferably 8.00 μm or less, and even more preferably 5.00 μm or less.

[0040] In this specification, the volume-average particle diameter (MV) of the cross-linked resin particles (B) is a value obtained by measuring using an aqueous dispersion in which the cross-linked resin particles (B) are dispersed in an aqueous medium. More specifically, the volume-average particle diameter (MV) of the cross-linked resin particles (B) is a value calculated by the following equation (1), i.e., equation (2), when, for a group of k cross-linked resin particles in total, the particle diameters of the individual cross-linked resin particles (B) included in the group are denoted as d1, d2, ...di...dk in ascending order, and the volumes of these individual cross-linked resin particles (B) are denoted as V1, V2, ...Vi...Vk (where Vi is the volume of the cross-linked resin particle with particle diameter di).

[0041]

number

[0042] Furthermore, a general-purpose measuring device can be used to measure the particle size and volume of the crosslinked resin particles (B) in the aqueous dispersion. An example of such a device is the MicrotracMT3300EXII manufactured by Nikkiso Co., Ltd. In addition, in this specification, the volume-average particle size of uncrosslinked resin particles can be measured by replacing "crosslinked resin particles" with "uncrosslinked resin particles" in the above method.

[0043] (Peroxide) The crosslinking structure in the crosslinked resin particles (B) is not particularly limited, but it is preferable that it is crosslinked using a peroxide. That is, it is preferable that the crosslinked resin particles (B) are crosslinked using a peroxide. When a peroxide is used, radicals generated by the decomposition of the peroxide act on the molecules of the resin (e.g., PHA) that make up the resin particles. As a result, the molecular chains of the resin that make up the resin particles can directly bond to each other, thereby forming a crosslinked structure.

[0044] If the crosslinked resin particles (B) are crosslinked using a peroxide, the aqueous dispersion containing the crosslinked resin particles (B) may contain substances derived from the peroxide used to introduce the crosslinked structure (such as peroxide decomposition products and unreacted peroxides). Alternatively, if the crosslinked resin particles (B) are crosslinked using a peroxide, substances derived from the peroxide used to introduce the crosslinked structure (such as peroxide decomposition products and unreacted peroxides) may be adhering to the surface of the obtained crosslinked resin particles (B). In other words, if the crosslinked resin particles (B) are crosslinked using a peroxide, the crosslinked resin particles (B) or the resin sheet may contain substances derived from the peroxide (such as peroxide decomposition products and unreacted peroxides). If the crosslinked resin particles (B) or the resin sheet contain substances derived from the peroxide, it can be determined that the crosslinked resin particles (B) were crosslinked using a peroxide by analyzing the crosslinked resin particles (B) or the resin sheet.

[0045] The peroxide may be an organic peroxide or an inorganic peroxide. Organic peroxides are preferred because they can more efficiently increase the gel fraction.

[0046] As the organic peroxide, it is preferable to use at least one selected from the group consisting of diacyl peroxide, alkyl peroxyester, dialkyl peroxide, hydroperoxide, peroxyketal, peroxycarbonate, and peroxydicarbonate, taking into consideration the heating temperature and / or time during the crosslinking treatment.

[0047] Examples of such organic peroxides include butyl peroxyneododecanoate, octanoyl peroxide, dilauroyl peroxide, succinic peroxide, a mixture of toluyl peroxide and benzoyl peroxide, benzoyl peroxide, bis(butyl peroxy)trimethylcyclohexane, butyl peroxylaurate, dimethyldi(benzoyl peroxy)hexane, bis(butyl peroxy)methylcyclohexane, bis(butyl peroxy)cyclohexane, and butyl peroxybenzo Eth, butylbis(butylperoxy)valerate, dicumyl peroxide, di-t-hexyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxypivalate, t-hexylperoxypivalate, t-butylperoxymethyl monocarbonate, t-pentylperoxymethyl monocarbonate, t-hexylperoxymethyl monocarbonate, t-heptylperoxymethyl monocarbonate, t-octylperoxymethyl monocarbonate, 1 1,3,3-Tetramethylbutyl peroxymethyl monocarbonate, t-butyl peroxyethyl monocarbonate, t-pentyl peroxyethyl monocarbonate, t-hexyl peroxyethyl monocarbonate, t-heptyl peroxyethyl monocarbonate, t-octyl peroxyethyl monocarbonate, 1,1,3,3-Tetramethylbutyl peroxyethyl monocarbonate, t-butyl peroxyn-propyl monocarbonate, t-pentyl peroxyn-propyl monocarbonate, t-hexyl peroxy Xyxy n-propyl monocarbonate, t-heptyl peroxy n-propyl monocarbonate, t-octyl peroxy n-propyl monocarbonate, 1,1,3,3-tetramethylbutyl peroxy n-propyl monocarbonate, t-butyl peroxyisopropyl monocarbonate, t-pentyl peroxyisopropyl monocarbonate, t-hexyl peroxyisopropyl monocarbonate, t-heptyl peroxyisopropyl monocarbonate, t-octyl peroxyisopropyl monocarbonate, 1,1,3,3-Tetramethylbutyl peroxyisopropyl monocarbonate, t-butyl peroxy n-butyl monocarbonate, t-pentyl peroxy n-butyl monocarbonate, t-hexyl peroxy n-butyl monocarbonate, t-heptyl peroxy n-butyl monocarbonate, t-octyl peroxy n-butyl monocarbonate, 1,1,3,3-tetramethylbutyl peroxy n-butyl monocarbonate, t-butyl peroxyisobutyl monocarbonate, t-pentyl peroxyisobutyl monocarbonate, t -Hexyl peroxyisobutyl monocarbonate, t-heptyl peroxyisobutyl monocarbonate, t-octyl peroxyisobutyl monocarbonate, 1,1,3,3-tetramethylbutyl peroxyisobutyl monocarbonate, t-butyl peroxysec-butyl monocarbonate, t-pentyl peroxysec-butyl monocarbonate, t-hexyl peroxysec-butyl monocarbonate, t-heptyl peroxysec-butyl monocarbonate, t-octyl peroxysec-butyl monocarbonate t,1,1,3,3-tetramethylbutyl peroxysec-butyl monocarbonate, t-butyl peroxyt-butyl monocarbonate, t-pentyl peroxyt-butyl monocarbonate, t-hexyl peroxyt-butyl monocarbonate, t-heptyl peroxyt-butyl monocarbonate, t-octyl peroxyt-butyl monocarbonate, 1,1,3,3-tetramethylbutyl peroxyt-butyl monocarbonate, t-butyl peroxy2-ethylhexyl monocarbonate, t-pentyl peroxy2-ethylhexyl Tylhexyl monocarbonate, t-hexyl peroxy 2-ethylhexyl monocarbonate, t-heptyl peroxy 2-ethylhexyl monocarbonate, t-octyl peroxy 2-ethylhexyl monocarbonate, 1,1,3,3-tetramethylbutyl peroxy 2-ethylhexyl monocarbonate, diisobutyl peroxide, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-Tetramethylbutyl peroxyneodecanoate, bis(4-t-butylcyclohexyl)peroxydicarbonate, bis(2-ethylhexyl)peroxydicarbonate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di(3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, disuccinate peroxide, 2,5-dimethyl-2,5-bis(2-ethylhexanoyl peroxy) Examples include hexane, t-hexylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoyl peroxide, t-butylperoxy-2-ethylhexyl carbonate, t-butylperoxyisopropyl carbonate, 1,6-bis(t-butylperoxycarbonyloxy)hexane, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyacetate, t-butylperoxybenzoate, t-amylperoxy,3,5,5-trimethylhexanoate, 2,2-bis(4,4-di-t-butylperoxycyclohexy)propane, and 2,2-di-t-butylperoxybutane. Organic peroxides may be used individually or in combination of two or more.

[0048] Among these organic peroxides, t-butyl peroxyisopropyl monocarbonate, t-pentyl peroxyisopropyl monocarbonate, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxy 2-ethylhexyl monocarbonate, t-pentyl peroxy 2-ethylhexyl monocarbonate, t-hexyl peroxy 2-ethylhexyl monocarbonate, t-amyl peroxyisopropyl monocarbonate, di-t-hexyl peroxide, and t-butyl peroxy 2-ethylhexyl peroxide are particularly noteworthy. Xanoates, t-butyl peroxyisobutyrate, t-hexyl peroxy 2-ethyl hexanoate, 1,1,3,3-tetramethylbutyl peroxy 2-ethyl hexanoate, t-butyl peroxypivalate, t-hexyl peroxypivalate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, and 1,1,3,3-tetramethylbutyl peroxyneodecanoate are preferred organic peroxides because they can efficiently promote the crosslinking of the resin constituting the resin particles.

[0049] The peroxide is preferably a compound exhibiting a 1-hour half-life temperature of 200°C or less, more preferably 170°C or less, and even more preferably 140°C or less, so that the heating temperature during the crosslinking treatment can be set low. The lower limit of the 1-hour half-life temperature of the peroxide may be 50°C or higher, 60°C or higher, or 70°C or higher.

[0050] Among organic peroxides exhibiting such a 1-hour half-life temperature, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy 2-ethylhexyl monocarbonate, di-sec-butyl peroxydicarbonate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxyisobutyrate, t-hexyl peroxy 2-ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxy 2-ethylhexanoate, t-butyl peroxypivalate, t-hexyl peroxypivalate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, and 1,1,3,3-tetramethylbutyl peroxyneodecanoate are particularly preferred.

[0051] The case where the peroxide is an inorganic peroxide will be described. Examples of such inorganic peroxides, taking into consideration the heating temperature and / or time during the crosslinking treatment, include hydrogen peroxide, potassium peroxide, calcium peroxide, sodium peroxide, magnesium peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate. Among these inorganic peroxides, hydrogen peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate are preferred in terms of ease of handling and having decomposition temperatures suitable for the heating temperature during the crosslinking treatment. One type of inorganic peroxide may be used alone, or two or more types may be used in combination. Furthermore, an organic peroxide and an inorganic peroxide may be used in combination.

[0052] (polyfunctional compound) The crosslinking structure in the crosslinked resin particles (B) may be introduced using only peroxides, but it is preferable that it be introduced using both peroxides and polyfunctional compounds. In other words, it is preferable that the crosslinked resin particles (B) are crosslinked in the presence of both peroxides and polyfunctional compounds. When both peroxides and polyfunctional compounds are used, it becomes possible to increase the gel fraction of the crosslinked resin particles (B) with a smaller amount of peroxide compared to when only peroxides are used.

[0053] The aforementioned polyfunctional compound refers to a compound having two or more functional groups (e.g., radical-reactive groups) in one molecule that can crosslink the resin (e.g., PHA) constituting the resin particles. The polyfunctional compound is not particularly limited, but compounds that have reactivity with radicals generated from peroxides are preferred, and compounds having two or more radical-reactive groups in one molecule are particularly preferred. As the radical-reactive group, at least one selected from the group consisting of vinyl group, allyl group, acryloyl group, and methacryloyl group is preferred.

[0054] Such polyfunctional compounds are not particularly limited, but examples include allyl (meth)acrylate; allylalkyl (meth)acrylates; allyloxyalkyl (meth)acrylates; polyfunctional (meth)acrylates having two or more (meth)acrylic groups, such as ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and pentaerythritol (meth)acrylate; and divinylbenzene, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and divinylbenzene. Preferably, it is one or more selected from the group consisting of allyl methacrylate, triallyl isocyanurate, butanediol di(meth)acrylate, and divinylbenzene, and particularly preferably one or more selected from the group consisting of allyl methacrylate and triallyl isocyanurate.

[0055] When a crosslinked structure is formed in the presence of a polyfunctional compound, the resulting crosslinked resin particles (B) may typically contain structures derived from the polyfunctional compound. In this case, the molecular chains of the resin constituting the resin particles are bonded together via structures derived from the polyfunctional compound.

[0056] (Other ingredients) The cross-linked resin particles (B) are cross-linked resin particles containing PHA. Therefore, the cross-linked resin particles (B) may be cross-linked resin particles containing only PHA, or they may be cross-linked resin particles containing other components besides PHA. Examples of the other components include resins other than PHA, antioxidants, hydrolysis inhibitors, blocking inhibitors, crystal nucleating agents, lubricants, ultraviolet absorbers, and so on.

[0057] The proportion of PHA in the crosslinked resin particles (B) is not particularly limited. The PHA content in 100% by weight of the resin component of the crosslinked resin particles (B) may be 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, even more preferably 90% by weight or more, particularly preferably 95% by weight or more, and may also be 99% by weight or more. There is no particular upper limit to the PHA content in 100% by weight of the resin component of the crosslinked resin particles (B), and it may be 100% by weight or less. Note that "resin component of crosslinked resin particles" refers to the resin that substantially constitutes the crosslinked resin particles, and does not include components that crosslink the molecular chains of the resin (e.g., structures derived from polyfunctional compounds) and residues of components used for crosslinking the molecular chains of the resin (e.g., unreacted peroxides, decomposition products of peroxides, unreacted polyfunctional compounds, etc.).

[0058] Examples of resins other than PHA include aliphatic polyesters other than PHA and aliphatic aromatic polyesters. Examples of aliphatic polyesters other than PHA include (i) polycaprolactone (PCL), (ii) polylactic acid (PLA), and (iii) aliphatic polyesters having a structure formed by the polycondensation of aliphatic diols and aliphatic dicarboxylic acids. Specific examples of aliphatic polyesters having a structure formed by the polycondensation of aliphatic diols and aliphatic dicarboxylic acids include polyethylene succinate, polybutylene succinate (sometimes referred to as "PBS"), polyhexamethylene succinate, polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polybutylene succinate adipate (sometimes referred to as "PBSA"), polyethylene sebacate, and polybutylene sebacate. Examples of the aliphatic aromatic polyester include aliphatic aromatic polyesters obtained by copolymerizing both aliphatic and aromatic compounds, using both aliphatic and aromatic compounds as monomers. Examples of the aliphatic aromatic polyester include polybutylene adipate terephthalate (hereinafter sometimes referred to as "PBAT"), polybutylene sebacate terephthalate (hereinafter sometimes referred to as "PBSeT"), polybutylene azelate terephthalate (hereinafter sometimes referred to as "PBAzT"), polybutylene succinate terephthalate (hereinafter sometimes referred to as "PBST"), and polybutylene succinate adipate terephthalate (hereinafter sometimes referred to as "PBSAT"). These resins other than PHA may be used individually or in combination of two or more. In the crosslinked resin particles (B), the resins other than PHA may or may not be crosslinked.

[0059] The cross-linked resin particles (B) are preferably non-foamed, unlike the foamed resin particles disclosed in International Publication No. 2007 / 049694 and International Publication No. 2019 / 146555. In other words, the cross-linked resin particles (B) are preferably substantially free of air bubbles. "Substantially free of air bubbles" means that the volume of air bubbles (space) is 10% or less of the total volume of the cross-linked resin particles (B).

[0060] When the cross-linked resin particles (B) are not foamed, their apparent density is relatively high. The apparent density of the cross-linked resin particles (B) is 0.6 g / cm³. 3 Preferably, it should exceed 0.7 g / cm³. 3 It is more preferable that the value be greater than or equal to 0.9 g / cm³. 3 It is even more preferable that the above conditions are met. The apparent density of the crosslinked resin particles (B) can be determined by the method described in JIS K0061 (Method for determining the density and specific gravity of chemical products) or JIS Z8807 (Method for determining the density and specific gravity of solids).

[0061] The average weight per particle of the cross-linked resin particles (B) is not particularly limited. For example, if the volume-average particle diameter of the cross-linked resin particles (B) is 10.00 μm or less, the average weight per particle of the cross-linked resin particles (B) may be far less than 0.1 mg.

[0062] The crosslinked resin particles (B) may be dried. Depending on the drying method, the shape after drying may be powder, pellet, crumb, film, or sheet.

[0063] (Manufacturing method for cross-linked resin particles (B)) An example of a method for producing the crosslinked resin particles (B) will be specifically described. The crosslinked resin particles (B) can be produced by crosslinking the molecular chains of the resin in an aqueous dispersion containing resin particles before crosslinking treatment, in the presence of a peroxide.

[0064] Note that "resin particles" refers to particles composed of resin components that substantially constitute crosslinked resin particles. If the resin component consists only of PHA, the resin particles can also be called PHA particles. To efficiently crosslink the molecular chains of the resin, it is preferable to heat the aqueous dispersion of resin particles containing peroxide to a temperature suitable for the decomposition of peroxide.

[0065] More specifically, the method for producing the crosslinked resin particles (B) preferably includes the steps of: (1) preparing an aqueous dispersion of resin particles in which resin particles (e.g., PHA particles) before crosslinking treatment are dispersed in water; (2) adding peroxide to the aqueous dispersion of resin particles to impregnate the resin particles with peroxide; and (3) heating the aqueous dispersion of resin particles impregnated with peroxide to a heating temperature to crosslink the molecular chains of the resin (e.g., the molecular chains of PHA). Furthermore, it is more preferable to include the step of maintaining the heating temperature after all the peroxide has been added (4).

[0066] In step (1), for example, the aqueous dispersion of PHA particles may be an aqueous dispersion obtained by culturing PHA-producing microorganisms to accumulate PHA within the cells, then destroying the cells in the culture medium and separating and removing the cell components, or an aqueous dispersion obtained by concentrating or diluting said aqueous dispersion. With this method, the process from producing PHA particles by culturing PHA-producing microorganisms to the crosslinking treatment can be carried out without separating the PHA particles from the water.

[0067] Furthermore, an aqueous dispersion of resin particles (e.g., PHA particles) can also be prepared by dispersing dried resin particles (e.g., PHA particles) in water.

[0068] The aqueous medium contained in the aqueous dispersion may be water alone, or it may be a mixed solvent of water and a water-miscible organic solvent. In this mixed solvent, the concentration of the water-miscible organic solvent is not particularly limited, as long as it is less than or equal to the solubility of the organic solvent used in water.

[0069] The aforementioned organic solvents are not particularly limited, but examples include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, pentanol, hexanol, and heptanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; nitriles such as acetonitrile and propionitrile; amides such as dimethylformamide and acetamide; dimethyl sulfoxide; pyridine; piperidine; and the like. Among these organic solvents, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, acetonitrile, and propionitrile are preferred because they are easy to remove. Furthermore, methanol, ethanol, 1-propanol, 2-propanol, butanol, and acetone are more preferred because they are readily available. In addition, methanol, ethanol, and acetone are particularly preferred.

[0070] The water content in the total aqueous medium (100% by weight) constituting the aqueous dispersion is preferably 5% to 100% by weight. The water content in 100% by weight of the aqueous medium is more preferably 10% by weight or more, more preferably 30% by weight or more, even more preferably 50% by weight or more, and particularly preferably 70% by weight or more. The water content in 100% by weight of the aqueous medium may be 90% by weight or more, or 95% by weight or more.

[0071] In the aqueous dispersion, it is preferable that the volume-average particle size of the resin particles is within the same range as the volume-average particle size of the cross-linked resin particles (B) described above. In the case of PHA particles produced by PHA-producing microorganisms, their volume-average particle size is usually within the above range, so an aqueous dispersion of PHA particles having a desirable volume-average particle size can be obtained without performing any special steps to adjust the particle size.

[0072] The concentration of resin particles in the aqueous dispersion is not particularly limited and can be set as appropriate, but for example, it may be about 1 to 70% by weight, and preferably about 5 to 50% by weight.

[0073] The aqueous dispersion of resin particles preferably contains a dispersant to enhance the dispersibility of the resin particles and allow the crosslinking reaction to proceed uniformly. Examples of dispersants include anionic surfactants such as sodium dioctyl sulfosuccinate, sodium dodecyl sulfate, sodium lauryl sulfate, and sodium oleate; cationic surfactants such as lauryl trimethylammonium chloride; nonionic surfactants such as glycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and polyoxyethylene polyoxypropylene glycol; and water-soluble polymers such as polyvinyl alcohol, ethylene-modified polyvinyl alcohol, polyvinylpyrrolidone, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, polyacrylic acid, sodium polyacrylate, potassium polyacrylate, polymethacrylic acid, and polysodium polymethacrylate. One type of dispersant may be used, or two or more types may be used in combination.

[0074] When a dispersant is used, the amount of dispersant in the aqueous dispersion is not particularly limited. The amount of dispersant in the aqueous dispersion may be, for example, 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, and particularly preferably 0.5 to 3 parts by weight, per 100 parts by weight of resin particles.

[0075] In step (2), peroxide is added to the aqueous dispersion of resin particles obtained in step (1) to impregnate the resin particles with peroxide. The peroxides described above can be used. Peroxides can be added in various forms, such as solid or liquid. Alternatively, liquid peroxides diluted with a diluent may be added. The peroxide may be added all at once, continuously, or in stages.

[0076] When using peroxides and the polyfunctional compound in combination, it is preferable to add the polyfunctional compound to the aqueous dispersion of resin particles in step (2). The polyfunctional compounds described above can be used. The polyfunctional compound can be added in various forms, such as solid or liquid. Alternatively, a liquid form diluted with a diluent may be added. The polyfunctional compound may be added all at once, continuously, or in portions.

[0077] In step (2), a method for impregnating the resin particles with peroxides and arbitrary polyfunctional compounds is to add these compounds to an aqueous dispersion of resin particles, or while adding them, set the temperature of the aqueous dispersion to, for example, 0°C or higher, but below the temperature suitable for the decomposition of the peroxide used in the next step (3), and maintain this temperature for, for example, 1 minute to 5 hours while stirring the aqueous dispersion. Specifically, the temperature of the aqueous dispersion during impregnation may be approximately 0°C to 80°C.

[0078] The amount of peroxide used can be appropriately set considering the gel fraction of the crosslinked resin particles (B). The amount of peroxide used is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 8 parts by weight, even more preferably 0.3 to 5 parts by weight, and particularly preferably 0.5 to 3 parts by weight per 100 parts by weight of resin particles.

[0079] In a manufacturing method that crosslinks resin particles in an aqueous dispersion using peroxides, it is easy to obtain crosslinked resin particles (B) by proceeding with crosslinking while maintaining the particle size (volume) before crosslinking. On the other hand, in a method that crosslinks resin by melt-kneading in the presence of peroxides, it can be difficult to achieve this.

[0080] Furthermore, the manufacturing method, which involves crosslinking resin particles in an aqueous dispersion using peroxides, has the advantage of making it easier to control the temperature rise caused by the heat generated during the crosslinking reaction, and efficiently obtaining crosslinked resin particles (B) with a safe and stable crosslinked structure (quality).

[0081] Furthermore, the amount of polyfunctional compound used can be appropriately set considering the gel fraction of the crosslinked resin particles (B). The amount of polyfunctional compound used is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 15 parts by weight, even more preferably 0.1 to 10 parts by weight, even more preferably 0.2 to 5 parts by weight, and particularly preferably 0.3 to 3 parts by weight per 100 parts by weight of resin particles.

[0082] In step (3), the aqueous dispersion of resin particles impregnated with peroxide is heated to a temperature suitable for the decomposition of the peroxide. The heating temperature is preferably within a range of approximately ±25°C (1-hour half-life temperature - 25°C to 1-hour half-life temperature + 25°C) based on the 1-hour half-life temperature of the peroxide mentioned above. Specifically, the heating temperature is preferably 30°C to 140°C, more preferably 50°C to 135°C, and even more preferably 60°C to 130°C. This method makes it possible to crosslink the resin (e.g., PHA) at a temperature lower than the melting temperature of the resin, thus avoiding deterioration of the resin due to heating during the crosslinking process. The melting temperature of PHA is, for example, 50°C to 210°C.

[0083] In the subsequent step (4), it is preferable to maintain the heating temperature. This allows the crosslinking reaction using the peroxide to proceed sufficiently. The time for maintaining the heating temperature is not particularly limited, but 1 minute to 15 hours is preferred, and 1 hour to 10 hours is more preferred.

[0084] After the crosslinking reaction is complete, the crosslinked resin particles (B) can be separated from the aqueous dispersion, and dried crosslinked resin particles (B) can be obtained by removing water from the separated crosslinked resin particles (B). The method for separating the crosslinked resin particles (B) from the aqueous dispersion is not particularly limited, and for example, filtration, centrifugation, heat drying, freeze-drying, spray drying, etc. can be used. For example, by using spray drying, dried crosslinked resin particles (B) can be obtained directly from the aqueous dispersion. Alternatively, the crosslinked resin particles (B) can be extruded individually after separation from the aqueous dispersion to completely remove any remaining moisture and obtain them in pellet form. Furthermore, a coagulation process may be carried out by using a coagulant and / or adjusting the pH.

[0085] The content of the crosslinked resin particles (B) in this resin sheet is 0.5 to 12.0 parts by weight per 100 parts by weight of the total amount of resin (A) and the crosslinked resin particles (B). In addition to this configuration, by including an inorganic filler (C) in an amount of 1.0 to 15.0 parts by weight per 100 parts by weight of the total amount, this resin sheet has the advantage of excellent thermoformability. Furthermore, this resin sheet also has the advantage of excellent appearance due to these configurations. To obtain a resin sheet with superior thermoformability and appearance, the lower limit of the content of the crosslinked resin particles (B) is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, and even more preferably 1 part by weight or more, per 100 parts by weight of the total amount. Furthermore, from the same viewpoint, the upper limit of the content of the crosslinked resin particles (B) is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less, based on 100 parts by weight of the total amount.

[0086] <Poly(3-hydroxyalkanoate) resin (A)> In this resin sheet, resin (A) can also be called the matrix resin. Resin (A) may consist of only one type of poly(3-hydroxyalkanoate) resin, or it may be a mixed resin containing two or more types of poly(3-hydroxyalkanoate) resins.

[0087] The resin (A) preferably contains a poly(3-hydroxybutyrate) resin. In this case, the resin sheet can exhibit the effect of excellent rigidity. Here, the poly(3-hydroxybutyrate) resin can be the same resin as the one listed above that contains 3HB repeating units and can constitute the crosslinked resin particles (B).

[0088] Furthermore, it is more preferable that the poly(3-hydroxybutyrate) resin contained in resin (A) contains a copolymer comprising 3-hydroxybutyrate units, i.e., 3HB, and other hydroxyalkate units. In this case, the resin sheet can achieve the effect of improving both rigidity and flexibility in a well-balanced manner. Here, the specific examples of the copolymer are the same as those described in the (PHA) section above, so we will refer to that description and omit the explanation here.

[0089] Resin (A) preferably contains at least two types of PHA with different repeating unit compositions, and more preferably contains at least two types of poly(3-hydroxybutyrate) resins with different repeating unit compositions. That is, the copolymer containing the 3-hydroxybutyrate units and other hydroxyalkate units is preferably a mixture of two or more copolymers with different 3-hydroxybutyrate unit content. In this case, the resin sheet can exhibit the effects of improved mechanical properties and accelerated crystallization.

[0090] The case in which resin (A) contains two types of poly(3-hydroxybutyrate) resins with different repeating unit compositions will be described. In this case, the two types of poly(3-hydroxybutyrate) resins will be referred to as resin (A-1) and resin (A-2), respectively. Resin (A-1) is not particularly limited, but from the viewpoint of obtaining a resin sheet with superior thermoformability and appearance, it is preferable that it be one or more selected from the group consisting of P3HB3HH and P3HB4HB, and more preferably P3HB3HH. The lower limit of the content of 3HB repeating units in resin (A-1) is not particularly limited, but from the viewpoint of obtaining a resin sheet with superior thermoformability and appearance, it is preferable that it be more than 90.0 mol%, more preferably 93.0 mol% or more, even more preferably more than 93.0 mol%, and particularly preferably 93.5 mol% or more of the total monomer repeating units (100 mol%) of resin (A-1). The upper limit of the content of 3HB repeating units in resin (A-1) is not particularly limited, but from the viewpoint of obtaining a resin sheet with superior thermoformability and appearance, it is preferably 99.0 mol% or less, more preferably 96.0 mol% or less, even more preferably 95.5 mol% or less, and particularly preferably 95.0 mol% or less. The resin (A-2) is not particularly limited, but from the viewpoint of obtaining a resin sheet with superior thermoformability and appearance, it is preferably one or more selected from the group consisting of P3HB3HH and P3HB4HB, and more preferably P3HB3HH. The lower limit of the content of 3HB repeating units in resin (A-2) is not particularly limited, but from the viewpoint of obtaining a resin sheet with superior thermoformability and appearance, it is preferably 75.0 mol% or more, more preferably 76.0 mol% or more, even more preferably 88.0 mol% or more, and particularly preferably more than 88.0 mol% of the total monomer repeating units (100 mol%) of resin (A-2).The upper limit of the content of 3HB repeating units in resin (A-2) is not particularly limited, but in order to obtain a resin sheet with superior thermoformability and appearance, it is preferably less than 93 mol%, more preferably 92.0 mol% or less, and even more preferably 90.0 mol% or less, out of the total monomer repeating units (100 mol%) of resin (A-2). The content of resin (A-1) in resin (A) is not particularly limited, but in order to obtain a resin sheet with superior thermoformability and appearance, it is preferably 55.0% to 95.0% by weight, more preferably 65.0% to 90.0% by weight, and even more preferably 75.0% to 85.0% by weight, out of the total content of resin (A-1) and resin (A-2) out of 100% by weight.

[0091] Resin (A) preferably has a gel fraction of less than 50%. Resin (A) is preferably not crosslinked.

[0092] Resin (A) contains a biodegradable resin, i.e., a biodegradable resin. As mentioned above, the cross-linked resin particles (B) are also biodegradable. Therefore, this resin sheet has the advantage of being able to enhance the biodegradability of the entire resin sheet and the molded product of the resin sheet. For this reason, this resin sheet is expected to be useful as an environmentally friendly resin sheet that addresses the problem of plastic waste. In addition, this resin sheet and its molded product can suppress soil pollution caused by disposal. This can contribute to achieving Sustainable Development Goals (SDGs), such as Goal 12, "Ensure sustainable consumption and production patterns." Furthermore, if the biodegradable resin contained in resin (A) and / or cross-linked resin particles (B) is marine biodegradable in addition to soil biodegradability, this resin sheet and molded product can suppress marine pollution in addition to soil pollution caused by disposal.

[0093] Furthermore, if the crosslinked resin particles (B) include resin manufactured from plant-derived raw materials, from the viewpoint of resource recycling, it is preferable that resin (A) also includes resin manufactured from plant-derived raw materials, and more preferably that it consists solely of resin manufactured from plant-derived raw materials.

[0094] The case where the crosslinked resin particles (B) contain P3HA will be described. In this case, the P3HA contained in resin (A) may be a resin with the same composition as the P3HA contained in crosslinked resin particles (B), or it may be a resin with a different composition. Preferably, the P3HA contained in resin (A) is a resin with a different composition and / or physical properties than the P3HA contained in crosslinked resin particles (B), and more preferably, it is a resin that is harder than the P3HA contained in crosslinked resin particles (B).

[0095] The weight-average molecular weight of resin (A) is not particularly limited, but is preferably 200,000 to 1,000,000, more preferably 300,000 to 900,000, and even more preferably 400,000 to 800,000. With this configuration, the resin sheet has the advantage of being highly thermoformable. With this configuration, the resin sheet also has the advantage of being highly aesthetic. Furthermore, if the weight-average molecular weight of resin (A) is 1,000,000 or less, it may also have the advantage of being easy to manufacture and / or easy to handle in order to achieve the objectives of one embodiment of the present invention.

[0096] Regarding aspects of P3HA other than those described above, they are the same as those explained in the (PHA) section above, so we will refer to that description and omit further explanation here.

[0097] The resin (A) content in this resin sheet is 88.0 parts by weight to 99.5 parts by weight per 100 parts by weight of the total amount of resin (A) and the aforementioned crosslinked resin particles (B). This configuration is equivalent to the configuration in which the crosslinked resin particles (B) content is 0.5 parts by weight to 12.0 parts by weight per 100 parts by weight of the total amount of resin (A) and the crosslinked resin particles (B). Therefore, as described above, by adding an inorganic filler (C) in an amount of 1.0 part by weight to 15.0 parts by weight per 100 parts by weight of the total amount, this resin sheet has the advantage of excellent thermoformability. Furthermore, this resin sheet also has the advantage of excellent appearance due to these configurations. Since this results in a resin sheet with superior thermoformability and appearance, the lower limit of the resin (A) content is preferably 76.5 parts by weight or more, more preferably 78 parts by weight or more, and even more preferably 80 parts by weight or more, based on 100 parts by weight of the total amount. Also, from the same viewpoint, the upper limit of the resin (A) content is preferably 98.5 parts by weight or less, more preferably 96 parts by weight or less, and even more preferably 95 parts by weight or less, based on 100 parts by weight of the total amount.

[0098] <Inorganic filler (C)> This resin sheet contains a predetermined amount of inorganic filler (C). This resin sheet has the advantage of excellent thermoformability due to the inclusion of the aforementioned predetermined amount of crosslinked resin particles (B) in addition to the predetermined amount of inorganic filler (C). Furthermore, this resin sheet also has the advantage of excellent appearance due to the inclusion of the aforementioned predetermined amount of crosslinked resin particles (B) in addition to the predetermined amount of inorganic filler (C).

[0099] Examples of inorganic fillers (C) include, but are not limited to, silica-based inorganic fillers (e.g., quartz, fumed silica, anhydrous silicic acid, fused silica, crystalline silica, amorphous silica, fillers obtained by condensing alkoxysilane, ultrafine amorphous silica, etc.), alumina, zircon, iron oxide, zinc oxide, titanium oxide, silicon nitride, boron nitride, aluminum nitride, silicon carbide, glass, silicone rubber, silicone resin, carbon fiber, mica, graphite, carbon black, ferrite, graphite, diatomaceous earth, white clay, clay, talc, kaolinite, calcium carbonate, manganese carbonate, magnesium carbonate, barium sulfate, silver powder, etc. These inorganic fillers (C) may be used individually or in combination of two or more types.

[0100] From the viewpoint of the appearance of the molded article, such as surface smoothness, the inorganic filler (C) is preferably a layered clay mineral. Furthermore, from the viewpoint of the moldability of the resin sheet, the inorganic filler (C) is preferably at least one selected from the group consisting of mica, talc, kaolinite, and calcium carbonate.

[0101] The inorganic filler (C) content in this resin sheet is 1.0 to 15.0 parts by weight per 100 parts by weight of the total amount of resin (A) and the crosslinked resin particles (B). By including the aforementioned predetermined amount of the crosslinked resin particles (B) in addition to this configuration, this resin sheet has the advantage of excellent thermoformability. Furthermore, this resin sheet also has the advantage of excellent appearance due to these configurations.

[0102] In particular, when the lower limit of the inorganic filler (C) content is 1.0 part by weight per 100 parts by weight of the total amount, the viscosity of the thermoplastic resin composition constituting the resin sheet during heating is improved, thereby extending the drawdown time of the resin sheet. In this case, the resin sheet is less affected by the elasticity of the resin constituting it during molding, and the appearance of the resin sheet and the molded article made from the resin sheet is also improved. As a result, the resin sheet has a beautiful appearance, and the occurrence of wrinkles and bridges during molding can be prevented or reduced. Furthermore, in this case, temperature unevenness due to heating during molding is less likely to occur in the resin sheet, and the occurrence of holes caused by such temperature unevenness can be further prevented or reduced. From this viewpoint, the lower limit of the inorganic filler (C) content is preferably 0.99 parts by weight or more, more preferably 2.9 parts by weight or more, and even more preferably 4.75 parts by weight or more, per 100 parts by weight of the total amount.

[0103] Furthermore, if the upper limit of the inorganic filler (C) content is 15 parts by weight per 100 parts by weight of the total amount, it is possible to prevent or reduce the occurrence of holes in the resin sheet caused by the inorganic filler (C). From this viewpoint, the upper limit of the inorganic filler (C) content is preferably 13 parts by weight or less, more preferably 10.7 parts by weight or less, and even more preferably 9 parts by weight or less, per 100 parts by weight of the total amount.

[0104] Furthermore, among the compounds described above as inorganic fillers (C), some may exhibit effects other than those of an inorganic filler (for example, as nucleating agents, and as colorants such as titanium dioxide and carbon black). In this specification, even if each of the compounds described above exhibits effects other than those of an inorganic filler, it shall be considered an inorganic filler, and its content shall be considered as the content of inorganic filler (C).

[0105] The volume-average particle size of the inorganic filler (C) is preferably 0.1 μm to 100 μm, more preferably 0.1 μm to 50 μm, even more preferably 0.1 μm to 30 μm, and particularly preferably 0.1 μm to 15 μm, as this provides excellent properties and / or processability for the resin sheet. This volume-average particle size can be measured using laser diffraction / scattering devices such as the "Microtrac MT3100II" manufactured by Nikkiso Co., Ltd. and the "LA-9050V2" manufactured by Horiba, Ltd.

[0106] The inorganic filler (C) may be surface-treated to improve its dispersibility in the resin sheet. Examples of surface treatment agents include higher fatty acids, silane coupling agents, titanate coupling agents, sol-gel coating agents, and resin coating agents.

[0107] The moisture content of the inorganic filler (C) is preferably 0.01% to 10.00%, more preferably 0.01% to 5.00%, and even more preferably 0.01% to 1.00%, as this helps to suppress the hydrolysis of the poly(hydroxyalkanoate) resin. This moisture content can be determined in accordance with JIS-K5101.

[0108] <Lubricant> The resin sheet may further contain a lubricant. The inclusion of a lubricant in the resin sheet can improve the surface smoothness of both the resin sheet and the molded article obtained by molding it.

[0109] The lubricant is not particularly limited. Examples of lubricants include, but are not limited to, fatty acid metal salts such as magnesium stearate and calcium stearate; fatty acid amides such as behenamide, stearamide, erucamide, oleamide, methylenebisstearate, and ethylenebisstearate; glycerin monofatty acid esters such as polyethylene wax, oxidized polyester wax, glycerin monostearate, glycerin monobehenate, and glycerin monolaurate; organic acid monoglycerides such as succinic acid saturated fatty acid monoglyceride; sorbitan fatty acid esters such as sorbitan behenate, sorbitan stearate, and sorbitan laurate; polyglycerin fatty acid esters such as diglycerin stearate, diglycerin laurate, tetraglycerin stearate, tetraglycerin laurate, decaglycerin stearate, and decaglycerin laurate; and higher alcohol fatty acid esters such as stearyl stearate. The lubricant may be used alone or in combination of two or more types.

[0110] The content of the lubricant (or the total content if multiple lubricants are used) is not particularly limited as long as it imparts lubricity to the resin sheet and the molded article obtained by molding the resin sheet. The content of the lubricant is preferably 0.01 to 20.00 parts by weight, more preferably 0.05 to 10.00 parts by weight, even more preferably 0.10 to 10.00 parts by weight, even more preferably 0.20 to 5.00 parts by weight, and particularly preferably 0.30 to 4.00 parts by weight per 100 parts by weight of resin (A). When the content of the lubricant is within the above range, the lubricant effect can be obtained while avoiding the bleed-out of the lubricant to the surface of the resin sheet and the molded article obtained by molding the resin sheet.

[0111] <Crystallizing agent> The resin sheet may further contain a crystal nucleating agent. When the resin sheet contains a crystal nucleating agent, if the resin (A) is a crystalline resin, crystallization during molding is promoted, potentially improving moldability, productivity, and other factors. The presence of a crystal nucleating agent in the resin sheet also offers the advantage of providing the resin sheet and the molded article obtained by molding it with superior heat resistance or mechanical properties.

[0112] The nucleating agent is not particularly limited and conventionally known ones can be used. Examples of the nucleating agent include inorganic substances such as talc, kaolinite, montmorillonite, mica, synthetic mica, clay, zeolite, silica, carbon black, graphite, boron nitride, zinc oxide, titanium oxide, tin oxide, calcium carbonate, magnesium carbonate, aluminum oxide, neodymium oxide, barium sulfate, sodium chloride, and metal phosphates; sugar alcohol compounds derived from natural products such as erythritol, pentaerythritol, galactitol, mannitol, and arabitol; polysaccharides such as chitin and chitosan; polyols such as aliphatic alcohols (polyols), polyvinyl alcohol, and polyethylene oxide; sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, magnesium benzoate, barium benzoate, lithium terephthalate, sodium terephthalate, and terephthalate. Organic carboxylic acid metal salts such as potassium oxalate, calcium oxalate, sodium laurate, potassium laurate, sodium myristate, potassium myristate, calcium myristate, sodium octacosanoate, calcium octacosanoate, sodium stearate, potassium stearate, lithium stearate, calcium stearate, magnesium stearate, barium stearate, sodium montanaate, calcium montanaate, sodium toluylate, sodium salicylate, potassium salicylate, zinc salicylate, aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium β-naphthalate, sodium cyclohexanecarboxylate, etc.; organic sulfonates such as sodium p-toluenesulfonate and sodium sulfisophthalate;Carboxylate amides such as ethylene stearate, ethylenebislaurate, palmitate, hydroxystearate, erucate, tris(t-butylamide) trimesinate, laurate esters, palmitate esters, oleate esters, stearate esters, erucate esters, N-oleyl palmitate, N-oleyl oleate, N-oleyl stearate, N-stearyl oleate, N-stearyl stearate, N-stearyl erucate, methylenebisstearate, ethylenebislaurate, ethylenebiscaprate, ethylenebisoleate, ethylenebisstearate, ethylenebiserucate, ethylene Examples include carboxylic acid esters such as lenbisisostearate, butylenebisstearate, and p-xylylenebisstearate; dicarboxylic acid derivatives such as dimethyl adipate, dibutyl adipate, diisodecyl adipate, and dibutyl sebacate; cyclic compounds having a functional group C=O and one or more functional groups selected from the group consisting of NH, S, and O in their molecule, such as indigo, quinacridone, and quinacridone magenta; sorbitol derivatives such as bisbenzylidene sorbitol and bis(p-methylbenzylidene) sorbitol; compounds containing nitrogen-containing heteroaromatic nuclei such as pyridine, triazine, and imidazole; phosphate ester compounds, bisamides of higher fatty acids, and metal salts of higher fatty acids; branched polylactic acid; and low molecular weight poly-3-hydroxybutyrate. These nucleating agents may be used individually or in combination of two or more.

[0113] The content of the nucleating agent is not particularly limited as long as it promotes the crystallization of resin (A). The content of the nucleating agent is preferably 0.05 to 12.00 parts by weight, more preferably 0.10 to 10.00 parts by weight, and even more preferably 0.50 to 8.00 parts by weight per 100 parts by weight of resin (A). When the content of the nucleating agent is within the above range, the effect of the nucleating agent can be obtained while suppressing a decrease in viscosity and physical properties of the molded article during molding.

[0114] <Other resins> The resin sheet may contain other resins besides the poly(3-hydroxyalkanoate) resin component, to the extent that it does not impair the effects of the invention. Examples of such other resins include aliphatic polyester resins such as polybutylene succinate adipate, polybutylene succinate, polycaprolactone, and polylactic acid, and aliphatic aromatic polyester resins such as polybutylene adipate terephthalate, polybutylene sebacate terephthalate, and polybutylene azelate terephthalate. The other resin may consist of only one type or two or more types.

[0115] The content of the other resins is not particularly limited, but is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, even more preferably 10 parts by weight or less, and particularly preferably 5 parts by weight or less, based on 100 parts by weight of the total amount of the poly(3-hydroxyalkanoate) resin components. It may also be 1 part by weight or less. The lower limit of the content of the other resins is not particularly limited and may be 0 parts by weight.

[0116] <Other ingredients> This resin sheet may contain other components such as plasticizers, organic fillers, antioxidants, hydrolysis inhibitors, ultraviolet absorbers, colorants such as dyes and pigments, and antistatic agents, to the extent that they do not impair the function of the resulting molded product.

[0117] The plasticizer is not particularly limited. Examples of the plasticizer include polyester-based plasticizers such as polypropylene glycol sebacate; aliphatic dibasic acid ester plasticizers such as di-1-butyl adipate, di-n-butyl sebacate and di-2-ethylhexyl azelaate; glycerin-based plasticizers such as glycerin diacetomonolaurate, glycerin diacetomonocaprylate, and glycerin diacetomonodecanoate; polycarboxylic acid ester plasticizers such as tri-2-ethylhexyl acetylcitrate and tributyl acetylcitrate; and poly(ethylene oxide-propylene oxide) block and / or random copolymers, poly(ethylene oxide-propylene oxide) block and / or random copolymers, polytetramethylene glycol, etc. Examples of plasticizers include lucylene glycol-based plasticizers; phosphate ester-based plasticizers such as diphenyl-2-ethylhexyl phosphate and diphenyloctyl phosphate; epoxy-based plasticizers such as epoxidized soybean oil and epoxidized linseed oil fatty acid butyl esters; and castor oil-based plasticizers such as castor oil fatty acid esters, methyl ricinoleates, ethyl ricinoleates, isopropyl ricinoleates, butyl ricinoleates, ethylene glycol monolicylate, propylene glycol monolicylate, trimethylolpropane monolicylate, sorbitan monolicylate, castor oil fatty acid polyethylene glycol ester, castor oil ethylene oxide adduct, castor oil-based polyols, castor oil-based toluene, or castor oil-based diols. These plasticizers may be used individually or in combination of two or more.

[0118] The organic filler is not particularly limited. Examples of the organic filler include fillers made from naturally derived materials such as wood-based materials (e.g., wood chips, wood powder, sawdust, etc.), rice husks, rice flour, starch, corn starch, rice straw, wheat straw, and natural rubber; organic fibers such as plant-derived natural fibers, animal-derived natural fibers, and synthetic fibers; and synthetic resins such as polyester, polyacrylic, polyamide, nylon, polyethylene, polyolefin, polyvinyl alcohol, polyvinyl chloride, polyurethane, polyacetal, aramid, PBO (poly-p-phenylenebenzobisoxazole), polyphenylene sulfide, acetylcellulose, polybenzazole, polyarylate, polyvinyl acetate, and synthetic rubber.

[0119] The aforementioned plant-derived natural fibers are not particularly limited. Examples of such plant-derived natural fibers include kenaf fiber, abaca fiber, bamboo fiber, jute fiber, hemp fiber, linen fiber, heneken (sisal), ramie fiber, hemp, cotton, banana fiber, coconut fiber, palm, paper mulberry, mitsumata, bagasse, etc. Also, regenerated fibers such as pulp, cellulose fiber, and rayon processed from plant fibers are also included. Examples of animal-derived natural fibers include wool, silk, cashmere, mohair, etc.

[0120] The antioxidant is not particularly limited. Examples of the antioxidant include phenolic antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and the like. These antioxidants may be used individually or in combination of two or more.

[0121] The hydrolysis inhibitor is not particularly limited. Examples of hydrolysis inhibitors include carbodiimide compounds, epoxy compounds, isocyanate compounds, oxazoline compounds, and the like. These hydrolysis inhibitors may be used individually or in combination of two or more.

[0122] The ultraviolet absorber is not particularly limited. Examples of ultraviolet absorbers include benzophenone compounds, benzotriazole compounds, triazine compounds, salicylic acid compounds, cyanoacrylate compounds, nickel complex salt compounds, and the like. These ultraviolet absorbers may be used individually or in combination of two or more.

[0123] The aforementioned colorants, such as pigments and dyes, are not particularly limited. Examples of colorants include inorganic colorants such as titanium dioxide, calcium carbonate, chromium oxide, cuprous oxide, calcium silicate, iron oxide, carbon black, graphite, titanium yellow, and cobalt blue; soluble azo pigments such as lake red, lysole red, and brilliant carmine; insoluble azo pigments such as dinitrian orange and fast yellow; phthalocyanine pigments such as monochlorophthalocyanine blue, polychlorophthalocyanine blue, and polybromophthalocyanine green; condensed polycyclic pigments such as indigo blue, perylene red, isoindolinone yellow, and quinacridone red; and dyes such as oraset yellow. These colorants may be used individually or in combination of two or more.

[0124] The antistatic agent is not particularly limited. Examples of the antistatic agent include low molecular weight antistatic agents such as fatty acid ester compounds, aliphatic ethanolamine compounds, and aliphatic ethanolamide compounds, as well as high molecular weight antistatic agents. These antistatic agents may be used individually or in combination of two or more.

[0125] Furthermore, this resin sheet contains catalyst deactivators (hindered phenol compounds, thioether compounds, vitamin compounds, triazole compounds, polyhydric amine compounds, hydrazine derivative compounds, phosphorus compounds, etc.), mold release agents (montanic acid and its salts, its esters, its half-esters, stearyl alcohol, stearamide, and polyethylene wax, etc.), color inhibitors (phosphates, hypophosphates, etc.), silane coupling agents (epoxysilane coupling agents, aminosilane coupling agents, (meth)acrylicsilane coupling agents, isocyanate silane coupling agents, etc.), and flame retardants (red phosphorus, phosphate esters, brominated polystyrene, brominated polyphenylene ether, brominated polystyrene). It may also contain materials such as recarbonate, aluminum hydroxide, magnesium hydroxide, melamine and cyanuric acid or its salts, silicon compounds, etc., conductive agents (carbon black, etc.), lubrication modifiers (graphite, fluororesin, etc.), epoxy compounds (glycidyl ether compounds, glycidyl ester compounds, polymer compounds grafted or copolymerized with glycidyl compounds, etc.), acid anhydride compounds (maleic anhydride, succinic anhydride, polymer compounds grafted or copolymerized with acid anhydrides, etc.), carbodiimide compounds (N,N'-di-2,6-diisopropylphenylcarbodiimide, 2,6,2',6'-tetraisopropyldiphenylcarbodiimide, polycarbodiimide, etc.).

[0126] The content of each of the other components described above is not particularly limited as long as it produces the effect of the embodiment of the present invention, and can be appropriately determined by those skilled in the art.

[0127] <Characteristics of resin sheets> In one embodiment of the present invention, the thickness of the resin sheet is not particularly limited. The lower limit of the thickness of the resin sheet may be 10 μm or more, 11 μm, 12 μm, 13 μm, 14 μm, or 15 μm. The upper limit of the thickness of the resin sheet may be 1000 μm or less, 900 μm, 800 μm, 700 μm, 500 μm, or 450 μm. In another embodiment of the present invention, the thickness of the resin sheet may be 600 μm to 1000 μm.

[0128] In one embodiment of the present invention, the drawdown time of the resin sheet is preferably 45 seconds or more, and more preferably 50 seconds or more. Because the drawdown time is above the aforementioned preferred lower limit, the resin sheet is heated uniformly during heat molding, resulting in less temperature unevenness. Therefore, the resin sheet has the advantage of suppressing uneven thickness during molding. Furthermore, the upper limit of the drawdown time of the resin sheet is not particularly limited and may be, for example, 60 seconds or less. Because the drawdown time is below the aforementioned preferred upper limit, the resin sheet maintains a viscosity and elasticity suitable for processing, and because a small amount of crystals remain, crystal growth occurs during annealing during molding, making deformation less likely during demolding. Therefore, the resin sheet has the advantage of providing a molded article with no wrinkles or very few bridging. In this specification, "drawdown time" is the time from the start of heating until the vertical distance from the lowest point of the resin sheet to the bottom surface of the resin sheet at the time it is fixed to the frame reaches 7 cm, when the resin sheet is heated to 400°C while sandwiched and fixed in a frame. Specifically, the "drawdown time" is the value (time) obtained by measurement using the method described in the later examples.

[0129] <Method for manufacturing resin sheets> This resin sheet can be manufactured by known methods. Specifically, methods including the steps shown in (1) and (2) below can be cited. (1) A step of preparing a thermoplastic resin composition by mixing each raw material, such as resin (A), crosslinked resin particles (B), inorganic filler (C), and other thermoplastic resins and / or other components as optional components. (2) A step of forming the thermoplastic resin composition prepared in step (1) into a sheet to obtain the resin sheet.

[0130] In step (1) above, the method for mixing the raw materials is not particularly limited, and known methods can be used. For example, a method for mixing the raw materials can be a melt-kneading method. The melt-kneading can be carried out using known equipment such as an extruder, kneader, Banbury mixer, or kneading roll. When melt-kneading the raw materials, it is preferable to mix the raw materials with care to prevent or reduce the decrease in molecular weight of the resin (A) and the crosslinked resin particles (B) due to thermal decomposition. Alternatively, the thermoplastic resin composition can be produced by dissolving all the raw materials (components) in a soluble solvent and then removing the solvent.

[0131] When manufacturing a thermoplastic resin composition by melt kneading, each component may be individually fed into an extruder or the like, or a mixture obtained by pre-mixing each component may be fed into an extruder or the like. For example, an aqueous dispersion of resin (A) and an aqueous dispersion of the crosslinked resin particles (B) may be mixed, and the resulting mixture may be dried in a dryer to obtain a mixed powder, which may then be fed into an extruder or the like.

[0132] When melt-kneaded using an extruder, the resulting thermoplastic resin composition may be processed into particle shapes such as bars, cylinders, elliptical columns, spheres, cubes, or rectangular parallelepipeds by extruding it from the extruder in a strand shape and then cutting it.

[0133] The resin temperature during melt mixing cannot be specified in general terms, as it depends on the melting point and melt viscosity of the resin used. From the viewpoint of uniformly dispersing the crosslinked resin particles (B) in the resin (A) while avoiding thermal decomposition of the resin (A), the resin temperature is preferably 140°C to 250°C, more preferably 140°C to 230°C, and even more preferably 140°C to 210°C.

[0134] In step (2) above, the method for molding the thermoplastic resin composition into a sheet is not particularly limited, and known methods can be used. Examples of such molding methods include molding the thermoplastic resin composition by methods such as inflation molding, extrusion blow molding, injection blow molding, extrusion molding, calendering, vacuum molding, injection molding, T-die extrusion molding, casting, rolling, and melt press. Among these, it is preferable to use inflation molding, calendering, T-die extrusion molding, casting, rolling, or melt press in step (2) above to mold the thermoplastic resin composition into a sheet to obtain the resin sheet. The resin sheet can be said to be a sheet (sheet molded body) formed by molding the thermoplastic resin composition, or a sheet (sheet molded body) containing the thermoplastic resin composition.

[0135] By implementing the molding method described above, this resin sheet can be manufactured with good productivity.

[0136] The aforementioned inflation molding method refers to a molding method in which a molten resin composition is extruded in a tubular shape from an extruder equipped with a cylindrical die at its tip, and immediately afterward, gas is blown into the tube to inflate it into a balloon shape, thereby forming a sheet (sheet molded body).

[0137] The calendering method described above refers to a molding method in which a sheet (sheet molded body) is formed by sandwiching a resin raw material, which has been heated to a molten state in advance, between multiple rolls and rolling it.

[0138] The aforementioned T-die extrusion molding method refers to a molding method in which a thermoplastic resin composition heated to a molten state in an extruder is discharged from a T-die outlet attached to the extruder to obtain a sheet-like thermoplastic resin in a molten state, and then the sheet-like thermoplastic resin is taken up while being sandwiched between a pair of smoothing rolls to cool and solidify, thereby forming a sheet (sheet molded body).

[0139] [2. Molded body] A molded article according to one embodiment of the present invention (hereinafter referred to as "the molded article") is a molded article obtained by molding the resin sheet. The molded article has the advantage that all of the perforations, wrinkles, and bridges are at a level that meets or exceeds the acceptable standard.

[0140] This molded article is formed by molding this resin sheet. This resin sheet contains the resin (A), the crosslinked resin particles (B), and the inorganic filler (C) described in the section [1. Resin Sheet] above, as well as other thermoplastic resins and / or other components as optional components. Therefore, this molded article may also contain the resin (A), the crosslinked resin particles (B), and the inorganic filler (C), as well as other thermoplastic resins and / or other components as optional components.

[0141] The molded article is not particularly limited in type, as long as it is a molded article made by molding the resin sheet, and may be any known type of molded article made by molding a resin sheet. The molded article may be, for example, a vacuum-formed article, a blow-formed article, a vacuum-pressure-formed article, an extruded article, or an injection-formed article. Among these, from the viewpoint of processability using cross-linked particles, the molded article is preferably a vacuum-formed article.

[0142] The shape of the molded body is not particularly limited and may be any known shape as a molded body made by molding a resin sheet. Examples of shapes of the molded body include pots, lids, cups, trays, and covers.

[0143] The method for molding this resin sheet to produce this molded body is not particularly limited and any known molding method for molding resin sheets can be used. Furthermore, the molding conditions when molding this resin sheet are not particularly limited. In other words, the type of molding method and molding conditions can be appropriately selected according to the type and shape of the desired molded body; for example, when producing a vacuum-formed molded body, a vacuum forming method should be used.

[0144] Specific types of the molding method mentioned above include, for example, vacuum forming, extrusion blow forming, injection blow forming, vacuum pressure forming, and hot plate forming.

[0145] This molded body can be suitably used as a seedling pot. In other words, a seedling pot either includes this molded body or consists of this molded body. A seedling pot that includes this molded body or consists of this molded body can also be considered one embodiment of the present invention. [Examples]

[0146] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to these examples.

[0147] [1. Measurement Method and Evaluation Method] The physical properties of the poly(3-hydroxyalkanoate) resin (A), crosslinked resin particles (B), and resin sheets described in Examples 1-4 and Comparative Examples 1-5 were measured and evaluated using the methods shown below.

[0148] 1-1. Weight average molecular weight The resin to be measured was added to chloroform, and the resulting mixture was heated in a 60°C hot water bath for 30 minutes. The resulting mixture (chloroform solution) was filtered through a PTFE disposable filter with a pore size of 0.45 μm. Subsequently, the weight-average molecular weight was determined by GPC measurement using the obtained filtrate under the following conditions. GPC measurement device: Shimadzu Corporation High-Performance Liquid Chromatograph 20A System Columns: Showa Denko KG 4A (1 piece), K-806M (2 pieces) Sample concentration: 1 mg / ml Free solution: Chloroform solution Free liquid flow rate: 1.0ml / min Sample injection volume: 100 μL Analysis time: 30 minutes Standard sample: Standard polystyrene.

[0149] 1-2. Volume-average particle diameter The volume-average particle diameter of the cross-linked resin particles (B) was measured using an aqueous dispersion of the cross-linked resin particles (B) as a sample. A MicrotracMT3300EXII manufactured by Nikkiso Co., Ltd. was used as the measuring device. Specifically, using the above device, the particle diameter and volume of each cross-linked resin particle (B) or uncross-linked resin particle in an aqueous dispersion of the cross-linked resin particles (B) or uncross-linked resin particles were measured, and the volume-average particle diameter was calculated from the results obtained based on the above-mentioned formula (1), i.e., formula (2).

[0150] 1-3. Gel fraction Dried cross-linked resin particles (B) were added to chloroform to a concentration of 0.7% by weight, and the mixture was held at 60°C for 30 minutes to obtain a chloroform solution. After standing at room temperature for 3 hours, the chloroform solution was filtered through a membrane filter with a pore size of 0.45 μm. Losses were prevented by thoroughly washing the inside of the container and the filter with chloroform multiple times during filtration. The gel remaining on the filter was dried, and its weight was measured along with the filter. The gel fraction was calculated using the following formula. Formula: Gel fraction = ((Weight of filter containing dry gel - Weight of filter only) / Weight of cross-linked resin particles (B) used for measurement) × 100 (%).

[0151] 1-4. Method for measuring the volume-average particle size of inorganic fillers The volume-average particle size of the inorganic filler was measured by laser diffraction. A scattering particle size distribution analyzer (LA-9050V2, manufactured by Horiba, Ltd.) was used as the measuring device, and the volume-average particle size was calculated under the following measurement conditions with the inorganic filler dispersed in water. [Measurement conditions] Particle refractive index: 1.59-0.11 Dispersion medium: water Refractive index of the dispersion medium: 1.33.

[0152] 1-5. Drawdown Time The method for measuring drawdown time will be explained with reference to Figure 1. Figure 1 is a schematic diagram showing the method for evaluating drawdown time in the example.

[0153] A resin sheet measuring 30 cm in the MD direction and 30 cm in the TD direction was fixed using a frame base 11 measuring 60 cm in length, 60 cm in width, and 6.5 cm in height, which had a square opening measuring 25 cm in length and 25 cm in width in the center. In detail, the frame base 11 consisted of an upper part 11a measuring 60 cm in length, 60 cm in width, and 3.25 cm in height, which had the opening, and a lower part 11b measuring 60 cm in length, 60 cm in width, and 3.25 cm in height, which also had the opening. The resin sheet was fixed to the center of the frame base 11 by sandwiching it between the upper part 11a and the lower part 11b of the frame base. At that time, the lower surface of the fixed resin sheet (i.e., the lower surface of the resin sheet before heating) was used as the fixing surface 15 of the resin sheet. The resin sheet was fixed at the boundary between the upper part 11a and the lower part 11b of the frame base 11, and therefore the fixing surface 15 of the resin sheet was also located at this boundary.

[0154] The frame 11, to which the resin sheet was fixed, was placed in a heating furnace set to 400°C and heated. As shown in Figure 1, over time, the resin sheet 12 hanging down from the opening of the frame 11 continued to hang down to its lowest point 14. At this time, the portion of the resin sheet corresponding to the area other than the opening, i.e., the end of the resin sheet 12 hanging down from the opening of the frame 11, was sandwiched between the upper part 11a and the lower part 11b of the frame and remained fixed to the frame 11. The time from the start of heating until the vertical distance from the fixed surface 15 of the resin sheet to the lowest point 14 of the resin sheet, i.e., the drawdown 13, reached 7 cm was measured. The measured time was defined as the drawdown time. The start of heating was defined as the time when the frame 11 and the resin sheet fixed to the frame 11 were placed in the heating furnace.

[0155] 1-6. Appearance of the resin sheet The appearance of the resin sheet, specifically the surface texture, was evaluated by touch according to the following criteria. A higher number indicates a better appearance. A score of 3 or higher was considered acceptable.

[0156] <Evaluation Criteria> • "4": Smooth and without any noticeable bumps or irregularities to the touch. • "3": You can feel the bumps and unevenness with your fingertips, but they are small. • "2": While it feels more textured to the touch than "3," the texture itself feels gentler. • "1": When touched with a finger, it feels like touching wallpaper, with a greater sense of unevenness than "2".

[0157] 1-7. Thermoformability of resin sheets (wrinkles, holes, bridging) (1) Thermoforming of resin sheets (manufacturing of molded products) Using a vacuum forming machine (FVS-500 manufactured by Wakisaka Engineering Co., Ltd.), a resin sheet heated to a heating temperature of 400°C for approximately 25 seconds was vacuum-formed (thermoforming) in a mold maintained at approximately 30-50°C. After cooling in the mold for approximately 5 seconds, the molded product was released from the mold within approximately 1 second to obtain a molded body.

[0158] The configuration of the mold was as follows: ·Shape: Square prism; • Dimensions: Depth 7cm x size of the bottom of the rectangular prism 6cm x 6cm and size of the top of the rectangular prism 9cm; and • Arrangement in the mold frame: Nine rectangular prism-shaped molds are arranged in a 30cm x 30cm mold frame, in other words, one rectangular prism-shaped mold is placed in the center of each 9.5cm x 9.5cm square.

[0159] (2) Evaluation of perforation in molded products The presence or absence of holes in the molded product was visually inspected. Based on the results, it was evaluated according to the following criteria. A higher number indicates fewer holes and superior thermoforming processability. A score of 2 or higher was considered acceptable. <Evaluation Criteria> • "3": The molded product after demolding, i.e., the molded body, has no holes (no holes have been formed). • "2": The molded product after demolding, i.e., the molded body, has holes (holes are formed), but the size of each hole is less than 2 mm in diameter, and the total number of holes per molded body is less than 4. • "1": The molded product after demolding, i.e., the molded body, has holes (holes are formed), and the size of each hole is 2 mm or larger in diameter, and / or the total number of holes is 4 or more per molded body.

[0160] (3) Evaluation of wrinkles in the molded product The presence or absence of wrinkles in the molded product was visually inspected. Based on the results, it was evaluated according to the following criteria. A higher number indicates fewer wrinkles and superior thermoformability. A score of 2 or higher was considered acceptable. <Evaluation Criteria> • "3": The molded product after demolding, i.e., the molded body, is free of wrinkles. • "2": The molded product after demolding, i.e., the molded body, has wrinkles, but the length of each wrinkle is less than 2 mm, and the total number of wrinkles per molded body is less than 4. • "1": The molded product after demolding, i.e., the molded body, has wrinkles, and the length of each wrinkle is 2 mm or more, and / or the total number of wrinkles is 4 or more per molded body.

[0161] (4) Evaluation of bridges in the molded body The presence or absence of bridging in the molded product was visually inspected. Based on the results, the product was evaluated according to the following criteria. A higher number indicates fewer bridging and superior thermoformability. A score of 2 or higher was considered acceptable. <Evaluation Criteria> • "3": Of the nine molded products obtained from the nine molds after demolding, i.e., the molded bodies, the number of molded bodies without bridges is three or less. • "2": Of the nine molded products obtained from the nine molds, i.e., molded bodies, four or more have bridges, but the size of each bridge is less than 2 mm in width, and the total number of bridges per molded body is less than four. • "1": Of the nine molded products obtained from the nine molds, i.e., molded bodies, four or more have bridges, and the size of each bridge is 2 mm or more in width, and / or the total number of bridges per molded body is four or more.

[0162] [2. Manufacturing Examples and Case Studies] [2-1. Manufacturing Example 1: Manufacturing of Crosslinked Resin Particles (B)] <Raw materials for cross-linked resin particles (B)> The following substances (1) to (3) were mainly used as raw materials for the cross-linked resin particles (B). (1) Uncrosslinked resin particles • Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate): Composition of repeating units; (3-hydroxybutyrate) / (3-hydroxyhexanoate) = 72 / 28 (mol / mol), weight-average molecular weight Mw: 500,000 to 1,500,000 The weight-average molecular weight of the resin was measured using the method described above. (2) Peroxides • Di-sec-butyl peroxydicarbonate (Luperox® 225, manufactured by Arkema Yoshitomi Co., Ltd., half-life temperature: 69°C). (3) Polyfunctional compound • Triallyl isocyanurate.

[0163] <Manufacturing method> An autoclave equipped with a stirrer, baffles, nitrogen inlet / outlet, and thermometer was prepared. 200 parts by weight of deionized water and 100 parts by weight of the uncrosslinked resin particles were added to the autoclave and stirred to disperse the uncrosslinked resin particles in the deionized water, preparing aqueous dispersion A in which the uncrosslinked resin particles were dispersed in water. Subsequently, 2 parts by weight of the peroxide, 1 part by weight of sodium dioctyl sulfosuccinate, and 0.5 parts by weight of the polyfunctional compound were further added to the autoclave to prepare aqueous dispersion B. Next, the autoclave was purged with nitrogen at room temperature (25±5℃). At the same time, stirring of the obtained aqueous dispersion B was started. The stirring was then continued continuously for 1 hour while maintaining the temperature at room temperature. As a result, the peroxide and the polyfunctional compound were impregnated into the interior of the uncrosslinked resin particles in aqueous dispersion B.

[0164] Subsequently, aqueous dispersion B was heated until its temperature reached 75°C. After the temperature of aqueous dispersion B reached 75°C, the aqueous dispersion B was held at that temperature for 3.5 hours. This caused the uncrosslinked resin particles, the peroxide, and the polyfunctional compound to react in aqueous dispersion B to produce crosslinked resin particles (B), resulting in an aqueous dispersion C in which the crosslinked resin particles (B) were dispersed in water.

[0165] The volume-average particle size and gel fraction of the cross-linked resin particles (B) in the obtained aqueous dispersion C were measured by the method described above. The volume-average particle size of the cross-linked resin particles (B) was 1.70 μm, and the gel fraction was 95%.

[0166] The pH of the aqueous dispersion C was adjusted, and the dispersion C with the adjusted pH was placed in an oven. The dispersion C was dried in the oven, and as a result, solidified cross-linked resin particles (B) were produced.

[0167] [Examples 1-4 and Comparative Examples 1-5: Manufacturing of Resin Sheets] <Raw materials for resin sheets> The following substances (4) to (7) were mainly used as raw materials for the resin sheets. (4) Poly(3-hydroxyalkanoate) resin (A) · A-1: ​​A polymer obtained according to the method described in International Publication No. 2008 / 010296, having a 3-hydroxyhexanoate (3HH) composition of 5.4 mol% and a weight-average molecular weight of 560,000. (3-Hydroxybutyrate-co-3-Hydroxyhexanoate)(P3HB3HH) · A-2: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH) obtained in accordance with the method described in International Publication No. 2013 / 147139, having a 3HH composition of 10.5 mol% and a weight-average molecular weight of 550,000. (5) Crosslinked resin particles (B) • Cross-linked resin particles (B) produced in manufacturing example 1. (6) Inorganic filler (C) • Talc (manufactured by Nippon Talc Co., Ltd.: Microace K-1, volume average particle size 8 μm) (7) Lubricant (D) • EW200 (manufactured by Riken Vitamin Co., Ltd., fatty acid ester).

[0168] <Manufacturing method> For each example and comparative example, the thermoplastic resin (A), crosslinked resin particles (B), inorganic filler (C), and lubricant (D) listed in Table 1 were mixed in the amounts specified in Table 1 to obtain a mixture. The obtained mixture was melt-kneaded for 3 minutes at a roll rotation speed of 17 rpm using two rolls heated to 145°C to obtain a resin sheet with a thickness of 700 μm. The appearance and drawdown time of the obtained resin sheet were evaluated. The results are shown in Table 1.

[0169] Furthermore, molded bodies were obtained by vacuum forming using the obtained resin sheets. The thermoformability of the obtained molded bodies was evaluated. The results are also shown in Table 1.

[0170] [result] The compositions of the resin sheets produced in Examples 1-4 and Comparative Examples 1-5, as well as the evaluation results of the resin sheets and molded articles, are shown in Table 1 below.

[0171] [Table 1]

[0172] As described in Manufacturing Example 1 and Examples 1-4, Comparative Examples 1-5, and Table 1, the resin sheets manufactured in Examples 1-4 satisfy the following requirements (i) and (ii) and thus qualify as the resin sheets described herein. (i) A poly(3-hydroxyalkanoate) resin (A), crosslinked resin particles (B) containing the polyhydroxyalkanoate resin and having a gel fraction of 50% or more, and an inorganic filler (C). (ii) The content of the poly(3-hydroxyalkanoate) resin (A) is 88.0 parts by weight to 99.5 parts by weight, the content of the crosslinked resin particles (B) is 0.5 parts by weight to 12.0 parts by weight, and the content of the inorganic filler (C) is 1.0 part by weight to 15.0 parts by weight, based on 100 parts by weight of the total amount of the poly(3-hydroxyalkanoate) resin (A) and the crosslinked resin particles (B).

[0173] On the other hand, the resin sheets described in Comparative Examples 1 to 5 do not satisfy the following requirements (i) and / or (ii), and therefore do not qualify as the resin sheets described herein.

[0174] Furthermore, as shown in Table 1, the evaluation of perforation, wrinkles, and bridging of molded articles obtained from the resin sheets manufactured in Examples 1 to 4 was "3" or "2," indicating that the resin sheets manufactured in Examples 1 to 4 have excellent thermoformability.

[0175] On the other hand, as shown in Table 1, the molded articles obtained from the resin sheets manufactured in Comparative Examples 1 to 5 all received a rating of "1" for perforation, wrinkles, and bridging, indicating that the resin sheets manufactured in Comparative Examples 1 to 5 are inferior in terms of thermoformability.

[0176] From the above, it was found that this resin sheet has excellent thermoformability. In other words, it was found that according to one embodiment of the present invention, a resin sheet with excellent thermoformability can be provided. [Industrial applicability]

[0177] According to one embodiment of the present invention, a resin sheet with excellent thermoformability can be provided. Therefore, one embodiment of the present invention can be suitably used in agriculture, fisheries, forestry, horticulture, medicine, hygiene products, food industry, clothing, non-clothing products, packaging, automobiles, building materials, and other fields. [Explanation of Symbols]

[0178] 11a Upper part of the frame base 11b Lower part of the frame base 11 Frame Stand 12. Resin sheet hanging from the opening of the frame base. 13 Drawdown 14. The lowest point of the resin sheet 15. Fixing surface of resin sheet

Claims

1. A resin sheet comprising a poly(3-hydroxyalkanoate) resin (A), crosslinked resin particles (B) containing the polyhydroxyalkanoate resin and having a gel fraction of 50% or more, and an inorganic filler (C), A resin sheet wherein, per 100 parts by weight of the total amount of the poly(3-hydroxyalkanoate) resin (A) and the crosslinked resin particles (B), the content of the poly(3-hydroxyalkanoate) resin (A) is 88.0 parts by weight to 99.5 parts by weight, the content of the crosslinked resin particles (B) is 0.5 parts by weight to 12.0 parts by weight, and the content of the inorganic filler (C) is 1.0 part by weight to 15.0 parts by weight.

2. The resin sheet according to claim 1, wherein the drawdown time of the resin sheet is 45 seconds or more. (Here, the drawdown time is the time from the start of heating until the vertical distance from the lowest point of the resin sheet to the bottom surface of the resin sheet when it is fixed to the frame reaches 7 cm, when the resin sheet is heated to 400°C with the resin sheet sandwiched and fixed in the frame.)

3. The resin sheet according to claim 1, wherein the poly(3-hydroxyalkanoate) resin (A) includes a poly(3-hydroxybutyrate) resin.

4. The resin sheet according to claim 3, wherein the poly(3-hydroxybutyrate) resin comprises a copolymer containing 3-hydroxybutyrate units and other hydroxyalkate units.

5. The resin sheet according to claim 4, wherein the copolymer containing the 3-hydroxybutyrate unit and other hydroxyalkate units is a mixture of two or more copolymers with different content of the 3-hydroxybutyrate unit.

6. The resin sheet according to claim 1, wherein the inorganic filler (C) is a layered clay mineral.

7. The resin sheet according to claim 1, wherein the inorganic filler (C) is one or more selected from the group consisting of mica, talc, kaolinite, and calcium carbonate.

8. A molded article obtained by molding a resin sheet according to any one of claims 1 to 7.

9. The molded body according to claim 8, which is a vacuum-formed body.

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