High bio-based hollow blow-molded article

Abstract

To provide a high bio-based hollow blow-molded article having an elevated proportion of biomass powder and also having the lowest possible resin content.SOLUTION: A hollow blow-molded article of the present invention contains (A) a thermoplastic resin and (B) a biomass component having a helical molecular structure, wherein the combined solid mass of components (A) and (B) is 90 pts.mass or more relative to 100 pts.mass of the molded article, the solid mass ratio of component (A) to component (B) is within the range of 40:60 to 70:30, and the bio-based content is 60% or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a hollow blow molded article with a high bio-based content, and more specifically to a hollow blow molded article having a bio-based content of 60% or more, and furthermore 90% or more. [Background technology]

[0002] In recent years, the movement towards decarbonization has accelerated, and there is a global trend towards replacing petroleum-derived raw materials with biomass and plant-derived raw materials. If the resin is derived from plants and biomass, even if it is incinerated, the carbon dioxide emitted will eventually be used to grow biological resources, making it a so-called carbon neutral and decarbonized environmental target.

[0003] For example, some manufacturers have commercialized plant-derived resins such as biopolyethylene. This is obtained from ethylene monomers obtained by fermenting sugarcane molasses and ethyl alcohol. Furthermore, in recent years, mass-balanced polypropylene, which is made by polymerizing propylene monomers using naphtha, which is obtained by mixing waste vegetable oil with mineral crude oil and distilling it, has also been put on the market. However, strictly speaking, it is difficult to call it a true biopolypropylene because it does not contain carbon derived from biomass (the Japan Organic Resources Association does not recognize it as being derived from biomass). In the near future, we are looking forward to the emergence of true biopolypropylene derived directly from biomass raw materials, and of course it can be used in the present invention.

[0004] An example of the current use of bio-polyethylene is plastic bags that contain 25% or more bio-polyethylene. According to the Plastic Bag Charge Law that came into effect in July 2020, plastic bags must in principle be sold for a fee, but stores can distribute plastic bags containing 25% or more bio-polyethylene for free to consumers even after the Plastic Bag Charge Law comes into effect.

[0005] Plastic bags are mainly manufactured by the inflation method or the T-die method. The inflation method is a method in which a circular die is attached to an extrusion molding machine, and the expanded bubble that comes out in a tubular shape is cooled and solidified by an air-cooling ring, and then wound up through a take-up machine. The T-die method is a method in which a T-die is attached to an extruder, and the molten resin film that comes out from a slit is rolled with a cooling roll, and the cooled and solidified film is wound up into a roll.

[0006] Also, a polypropylene resin composition containing polypropylene resin (A), biomass-derived synthetic resin (B), and biomass-derived filler (C) and having a biomass ratio of 20% to 80% has been proposed (see Patent Document 1). In the examples, a vacuum molded body is produced using a composition containing 37 parts by mass of polypropylene resin (A), 20 parts by mass of biomass-derived synthetic resin (B), and 30 parts by mass of wood flour: cedar (50 mesh) (C) and having a biomass ratio of 49.0%. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2023-066491 A Summary of the Invention [Problem to be solved by the invention]

[0008] In the coming carbon-neutral society, it is expected that biomass-derived materials will become more widespread and will likely become more common as legislation improves. Therefore, it would be desirable to make biomass-derived resins applicable to other molding methods, in addition to plastic bags and vacuum molded products.

[0009] Biopolyethylene is already commercially available in blow molding grades, and if plant-derived resins made from this are used, it is possible to achieve the plastic-free (petroleum-free, carbon-free) goal of the national strategy for plastic resource circulation, even in blow molding. However, even if plant-derived resins (bioplastics) themselves have a high bio-based content, they are still plastics, and plant-derived resin products are classified as plastics. Therefore, if we aim to create a material that is classified as a true biomass material, which is a higher-level material with a majority of the biomass powder itself, we must keep the content of plant-derived resins in the composition as low as possible and increase the proportion of biomass powder to be mixed in to 50% or more. If it is classified as a biomass composition, it is generally possible to reuse it in containers, etc., and then dispose of it as combustible waste instead of plastic waste.

[0010] It is relatively easy to increase the concentration of biomass powder (reducing the concentration of plant-derived resin) when forming films such as injection molded bodies or thick sheets. However, in the case of blow molding, air is blown into the molten resin from the inside to inflate it and mold it, so if the biomass powder is highly concentrated, it cannot withstand the expansion of the blown air, causing the molten resin to break, and it is not possible to obtain a blow molded product.

[0011] Therefore, an object of the present invention is to provide a hollow blow molded article with a high bio-based content, in which the proportion of biomass powder is increased and the resin content is kept as low as possible. [Means for solving the problem]

[0012] As a result of intensive research into achieving the above object, the inventors discovered that by making the biomass component have a helical molecular structure, the proportion of biomass powder can be increased while preventing the molten resin from cracking and breaking during the manufacturing process, even in blow molding, and thus completed the present invention. Specifically, the present invention provides the following.

[0013] A first aspect of the invention provides a hollow blow molded product comprising (A) a thermoplastic resin and (B) a biomass component having a helical molecular structure, wherein the total mass of the solid contents of the (A) component and the (B) component is 90 parts by mass or more per 100 parts by mass of the molded product, the mass ratio of the solid contents of the (A) component to the (B) component is within a range of 40:60 to 70:30, and the bio-based content is 60% or more.

[0014] According to the first aspect of the invention, it is possible to provide a hollow blow molded body having a high bio-based content of 60% or more, while suppressing the thermoplastic resin content to 70 parts by mass or less per 100 parts by mass of the total of the thermoplastic resin and biomass component.

[0015] Generally, as the content of biomass components increases, the brittleness and hardness of the composition itself becomes significant. Although it may be able to withstand injection molding or sheet molding, in the case of blow molding or inflation molding, air is blown into the molten resin from the inside to inflate it and form it. If the biomass powder is at a high concentration, it will not be able to withstand the expansion of the air being blown in, and the molten resin will crack or break, making it impossible to obtain a blow-molded product or film.

[0016] In the present invention, the biomass component has a helical molecular structure. So-called starch, including processed starch, is a polymer of glucose units, but since the units are linked by α-1,4 bonds, it is a polymer that takes a helical shape. On the other hand, cellulose is also a polymer of glucose units, but since the units are linked by β-1,4 bonds, it is a polymer that takes a linear shape. For this reason, when a composite material of starch and polymer is stretched by stress in a molten state, it is considered that the helical structure follows and stretches like a coil spring. As a result, in the present invention, it is considered that the helical molecular structure of the biomass component (e.g., starch filler) causes a unique behavior, and blow molding is possible even when a large amount of biomass component (50% or more) is added.

[0017] Moreover, even linear and rigid cellulose molecules and wood flour particles can be blow molded at low concentrations of about 30% due to the extensibility of the polymer (see Reference Examples below), but if you want to increase the concentration of these fillers, blow molding becomes possible if they are coexisted with starch. In other words, the present invention is achieved by the unique phenomenon that the extensibility of a filler composite resin can be improved by coexisting starch.

[0018] A second aspect of the present invention provides the molded article according to the first aspect, in which the component (A) is a biopolyethylene resin.

[0019] According to the second aspect of the invention, a blow molded article having high ductility can be obtained using a versatile material. In addition, since the thermoplastic resin is derived from plants, the bio-based content can be increased.

[0020] The third aspect of the invention is a hollow blow molded body made of a biomass classification material, which is the molded body according to the first aspect, and in which the mass ratio of the solid content of the (A) component to the (B) component is within the range of 40:60 to 50:50.

[0021] According to the invention relating to the third feature, it is possible to obtain a material classified as true biomass, which has a majority of the biomass powder content and is of a higher order than the plastic resource circulation strategy that the country is aiming for. For example, if starch is used and the starch content is increased to 50% or more, it is possible to provide a biomass material classified as a starch material that goes beyond the scope of plastic material classification.

[0022] A fourth aspect of the present invention provides the molded article according to the first aspect, wherein the bio-based content is 90% or more.

[0023] According to the fourth aspect of the invention, it is possible to provide a blow molded article having a bio-based content of 90% or more, in which the thermoplastic resin content is suppressed to 70 parts by mass or less per 100 parts by mass of the total of the thermoplastic resin and biomass component.

[0024] The fifth feature of the invention is the molded article according to the first feature, which has a layer made of a thermoplastic resin that is the same as or different from the component (A) laminated on the inner surface.

[0025] According to the fifth feature of the invention, since the molded body contains a chemically stable inner layer (thermoplastic resin layer), it is possible to prevent the biomass components contained in the molded body from being damaged by the contents of the blow molded body, such as food, beverages, tablets, and other container bottles. In other words, the resin layer, such as polyethylene, which has a proven track record in terms of food safety, plays a protective role. When various aqueous solutions and oils and fats come into direct contact with the contents of the blow molded body other than food, it is possible to prevent the biomass components contained in the molded body from coming into direct contact with the contents of the blow molded body. Effect of the Invention

[0026] According to the present invention, it is possible to provide a hollow blow molded article with a high bio-based content, in which the proportion of biomass powder is increased and the resin content is kept as low as possible. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Specific embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments and can be modified as appropriate within the scope of the object of the present invention.

[0028] <Hollow blow molding> The hollow blow molded article contains (A) a thermoplastic resin and (B) a biomass component having a helical molecular structure.

[0029] [(A) Thermoplastic resin]

[0030] The type of thermoplastic resin is not particularly limited, and may be any of polyolefin-based resins, polyester-based resins, and polystyrene-based resins, or a mixture thereof. The thermoplastic resin may be a biodegradable resin having biodegradability. Among them, the thermoplastic resin is preferably derived from plants, since this allows the biobased degree to be increased.

[0031] In the present invention, "derived from plants" means that it contains carbon derived from plant raw materials, for example, that it is produced using monomers obtained from plants as raw materials. Although not particularly limited, examples of plant materials rich in sugars include sugarcane and sugar beet, plant materials rich in starch include potatoes, cassava, wheat kernels and corn kernels, and lignocellulosic plant materials include wood-based materials, particularly wood-based waste. In addition, fossil fuel-derived monomers can be used in combination with some of the polymerization raw material monomers and copolymerization monomers as necessary.

[0032] Among the thermoplastic resins derived from plants, taking into consideration their high versatility as bioplastics, suitability for blow molding, chemical resistance, extensibility, and the like, it is more preferable that component (A) be a plant-derived polyolefin resin, and particularly preferably a plant-derived polyethylene resin.

[0033] In the following, as an example, the case where the thermoplastic resin is a plant-derived polyolefin resin will be described, but the same applies when the resin is derived from fossil fuels, and when the structural formula of the resin is another structural formula (for example, polyester-based resin and polystyrene-based resin). Ethylene, propylene, and α-olefins (1-butene, 1-hexene, etc.), which are monomers constituting the plant-derived polyolefin resin, are derived from fermented ethanol produced by allowing a microorganism to act on a culture solution obtained from these plant materials. Then, a polymerization reaction produces a homopolymer of the plant-derived olefin, or a polymer by polymerizing this plant-derived olefin with, for example, a petroleum-derived olefin or other monomer. The polymerization reaction from the olefin to the polyolefin resin can be carried out by a conventional method using a catalyst or the like.

[0034] Specific examples of the plant-derived polyolefin resin used in the present invention include medium-density or high-density polyethylene, high-pressure low-density polyethylene, linear low-density polyethylene, polypropylene, and α-olefin copolymers (ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, and ionically crosslinked olefin copolymer (ionomer)), which are obtained by polymerizing the plant-derived olefin derived from the above-mentioned fermentation ethanol.

[0035] The plant-derived polyolefin resin used in the present invention has a density of, for example, 0.890 to 0.980 g / cm according to ASTM D792. 3 Examples include those in between.

[0036] The melting point of the plant-derived polyolefin resin is not particularly limited, but is preferably 170° C. or lower, and more preferably 165° C. or lower. By using a plant-derived polyolefin resin with a lower melting point, the temperature during blow molding can be lowered. The melting point of the plant-derived polyolefin resin is preferably 85° C. or higher, and more preferably 95° C. or higher.

[0037] In light of the blow moldability of the biomass plastic composition, the melt flow rate (ASTM D1238, temperature: 190°C, load: 2.16 kg) of the plant-derived polyolefin resin is preferably 0.2 to 3.0 g / 10 min, and more preferably 0.2 to 2.0 g / 10 min. The biobased content (%) of plant-derived polyolefin resins, particularly plant-derived polyethylene resins, can be calculated from the composition, but as a final confirmation, the radiocarbon 14C content measured according to ASTM D6866-22 is preferably 70% or more, and more preferably 90% or more.

[0038] [Plant-derived polyethylene resin] Considering suitability for blow molding, chemical resistance, extensibility, and the like, the plant-derived polyolefin resin preferably contains a biopolyethylene (PE) resin.

[0039] Plant-derived ethylene, a monomer that constitutes plant-derived polyethylene resin, is derived by a dehydration reaction from fermented ethanol produced by the action of microorganisms on blackstrap molasses obtained from sugarcane and sugar beets, which contain a lot of sugar. There is also a method of producing fermented ethanol from starch such as corn. Conventional methods can be used for the polymerization reaction from the ethylene to polyethylene resin. Furthermore, to improve stress cracking properties (ESCR properties), petroleum-derived propylene, 1-butene, etc. are usually used as comonomers to be copolymerized with plant-derived ethylene. Therefore, the bio-based content of plant-derived polyethylene alone is generally less than 100%.

[0040] Other sources of the resin include starch-rich plant materials such as wheat kernels and corn kernels, and lignocellulosic plant materials including wood-based materials, particularly wood-based waste materials.

[0041] Specific examples of the plant-derived polyethylene resin used in the present invention include high-density polyethylene, medium-density polyethylene, high-pressure low-density polyethylene, linear low-density polyethylene, and mixtures thereof, which are obtained by polymerizing plant-derived ethylene derived from the fermentation ethanol.

[0042] For example, the plant-derived high density polyethylene resins (high density polyethylene) "SGF4950" and "SHE150" manufactured by Braskem GreenPE can be used as the plant-derived polyethylene resin of the present invention. The bio-based content of these products is 96% and 94% according to the catalog values.

[0043] (B) Biomass components with helical molecular structure Biomass components refer to resources born from living organisms, and are obtained from various sources, such as thinned wood from forests, livestock waste, and food waste. Among them, the biomass components used as component (B) have a helical molecular structure. Examples of biomass components having a helical molecular structure include starch and / or modified starch. In addition, when the biomass component is component (B), it can be included in the composition at a relatively high ratio compared to other biomass components, i.e., biomass components that do not have a helical molecular structure, and it has been found that even when the ratio of the biomass component is increased and the content of plant-derived resin is kept low, the molten resin can be blow molded without cracking or breaking when stretched under stress. This can be understood as an image of the helical molecular structure biomass following and stretching like a coil spring when stretched under stress, forming a network.

[0044] In the case of biomass components that do not have a helical molecular structure, such as cellulose, increasing the proportion of the biomass components and further reducing the content of plant-derived resin is not preferable because it causes the molten resin to crack during blow molding. However, even in these cases, it is possible to prevent cracking and breaking by coexisting starch, which has a helical molecular structure.

[0045] Of starch, 20-25% is amylose and 75-80% is amylopectin.

[0046] Amylose has a structure in which many α-glucose units are dehydrated and condensed between the hydroxyl groups (-OH) at the 1st and 4th positions, like maltose (malt sugar) (α-1,4-glycosidic bond). This structure is actually a linear spiral structure because it is connected in a bent manner like maltose. The -OH in the molecule is used for intramolecular hydrogen bonds that reinforce the spiral structure. The part where α-glucose molecules are polymerized in a linear chain is a spiral structure of about one turn with six α-glucose residues due to hydrogen bonds. The spiral structures are also arranged in parallel with each other through hydrogen bonds to form a crystal structure. The molecules can form crystals in a double spiral state or a single spiral state. First, there are three types of double-helical crystals: those in which the hydroxyl groups on the glucose residues form direct hydrogen bonds (Type A, derived from cereals such as cornstarch), those with a single water molecule between them (Type B, derived from rhizomes and bulbs such as potatoes), and those that are a mixture of both (Type C, derived from roots).Single-helical crystals are called Type V, and in nature exist as inclusion complexes in which the fat and oil components contained in starch granules are included in the single helix of amylose.

[0047] Amylopectin has a structure in which many α-glucose units are dehydrated and condensed between the 1- and 4-OH groups, and between the 1- and 6-OH groups (α-1,4-glycosidic bonds, α-1,6-glycosidic bonds). Due to the presence of 1,4 and 1,6 bonds, amylopectin has a branched spiral structure, unlike amylose.

[0048] The starch may be any of those classified as waste biomass, unused biomass, or resource grains. The biomass material may also be of animal origin, such as eggshells.

[0049] The origin of the starch is not particularly limited, and may be, for example, derived from cassava, corn, potato, sweet potato, sago, tapioca, sorghum, bean, bracken, lotus, water chestnut, wheat, rice, oats, arrowroot, pea, etc. Specifically, starch derived from corn or potato may be high amylose starch derived from corn or potato. One type of starch may be used or two or more types may be combined. The starch may also include modified starch, such as hydroxypropyl starch, etherified starch, esterified starch, cationized starch, or crosslinked starch.

[0050] The starch may be commercially available, typically ST Starch P (Nippon Starch Chemical Co., Ltd.), etc. In addition, modified starches that have been subjected to chemical, physical, or biological treatments may also be used.

[0051] The average particle size of the primary particles of component (B) is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. If the average particle size of component (B) is large, the molten resin is likely to crack during blow molding, which is not preferable. The lower limit of the average particle size is not particularly limited, but in consideration of operability, it is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more.

[0052] In the present invention, the average particle size of the primary particles of component (B) contained in the blow molded product is measured by a photo-imaging method. Specifically, the minor axis diameter and major axis diameter of each primary particle of component (B) are measured from an enlarged image of an electron-stained molded product sample taken with a transmission electron microscope (TEM) using image analysis software, and the average is taken as the primary particle size of the component (B). Next, the volume of each component (B) is calculated by approximating it to a sphere with the calculated primary particle size, and the volume average particle size is taken as the average primary particle size.

[0053] [Proportion of component (A) and component (B)] The total mass of the solid contents of the (A) and (B) components, excluding additive components, is 90 parts by mass or more, preferably 95 parts by mass or more, and more preferably 97 parts by mass or more, per 100 parts by mass of the molded product. The higher this total mass ratio is, the higher the bio-based content (the percentage of carbon contained in the hollow blow molded product that is derived from biomass) can be.

[0054] In addition, the mass ratio of the solid content of the (A) component to the (B) component is within the range of 40:60 to 70:30. In general, as the content of the biomass component ((B) component) increases, the brittleness and hardness of the composition itself become significant, and even if it can withstand injection molding or sheet molding, in the case of blow molding, air is blown into the molten resin from the inside to inflate it and mold it, so if the biomass powder is highly concentrated, it cannot withstand the blowing of air, the molten resin cracks, and a blow molded product cannot be obtained. However, in the invention described in this embodiment, a unique behavior is exhibited due to the helical molecular structure of the biomass component, and blow molding is possible even if a large amount of the biomass component is added.

[0055] The mass ratio is preferably within the range of 40:60 to 50:50. Even if the plant-derived resin (component (A)) itself has a high bio-based content, the plant-derived resin itself is classified as a plastic material, and if the blending ratio of component (A) is 50% or more, the blow-molded product falls into the category of plastic products. Therefore, if a true biomass-classified material with a higher blending ratio of biomass powder in the majority is aimed for, it is required to keep the content of plant-derived resin in the composition as low as possible. In the case of molding of injection molded products or thick sheets, it is relatively easy to increase the concentration of biomass powder (reduce the concentration of plant-derived resin), but in the case of blow molding, air is blown into the molten resin from the inside and the resin is expanded to form it. Therefore, when the concentration of biomass powder becomes high, it becomes increasingly unable to withstand the blowing of air, the molten resin cracks, and a blow-molded product cannot be obtained.

[0056] According to the invention described in this embodiment, it is possible to provide a hollow blow molded body made of a true biomass classified material that goes beyond the category of plastic material classification and is on a higher level than the plastic resource circulation strategy that the country is aiming for.

[0057] [Bio-based content] Biobased content is the percentage of carbon contained in a hollow blow molded body that is derived from biomass. Biobased content (%) can be determined, for example, by measuring the content of radioactive carbon-14C according to ASTM D6866-22 using an accelerator mass spectrometer (AMS). Of the three types of carbon, carbon-12 (C12), carbon-13 (C13), and carbon-14 (C14), carbon-14 is not found in fossil resources such as petroleum, and carbon-14 is always present in the atmosphere at a constant rate and decreases at fixed intervals until it is half its original amount in 5,730 years (half-life), and this property is used to determine the biobased content.

[0058] The calculated values ​​for the bio-based degree of the present invention are shown in Table 1. The bio-based degree of the biomass components was set to 96% for bio-polyethylene SGF4950, 94% for SHE150 (values ​​listed in the catalogue), and 100% for starch, wood flour, and cellulose, and the sum of the products of the content and bio-based degree of each component was used as the calculated value.

[0059] The bio-based content of the hollow blow molded body described in this embodiment is 60% or more, preferably 70% or more, more preferably 80% or more, even more preferably 90% or more, and particularly preferably 95% or more. The hollow blow molded body of the present invention can contribute to the achievement of Goal 12 (ensure responsible consumption and production, and sustainable production and consumption patterns) among the 17 Sustainable Development Goals (SDGs), which are international goals aimed at a sustainable and better world by 2030 as described in the "2030 Agenda for Sustainable Development" adopted at the United Nations Summit in September 2015.

[0060] [Additives] The hollow blow molded article in this embodiment may contain various additives within the range that does not impair the effects described in this embodiment. Examples of additives that can be used depending on the purpose include lubricants, crystallization nucleating agents, plasticizers, hydrolysis inhibitors, antioxidants, low-melting-point additives, release agents, ultraviolet absorbers, colorants such as dyes and pigments, and inorganic fillers.

[0061] [Lubricant] The type of lubricant is not particularly limited. For example, metal soap such as calcium stearate, hydrocarbon such as paraffin, fatty acid amide such as behenic acid amide, stearic acid amide, erucic acid amide, oleic acid amide, alkylene fatty acid amide such as methylene bis stearic acid amide, ethylene bis stearic acid amide, polyethylene wax, oxidized polyester wax, glycerin mono fatty acid ester such as glycerin monostearate, glycerin monobehenate, glycerin monolaurate, organic acid monoglyceride such as succinic acid saturated fatty acid monoglyceride, sorbitan fatty acid ester such as sorbitan behenate, sorbitan stearate, sorbitan laurate, polyglycerin fatty acid ester such as diglycerin stearate, diglycerin laurate, tetraglycerin stearate, tetraglycerin laurate, decaglycerin stearate, decaglycerin laurate, higher alcohol fatty acid ester such as stearyl stearate, hydrogenated hardened oil, etc. These may be used alone or in combination of two or more.

[0062] [Crystallization nucleating agent] The type of crystallization nucleating agent is not particularly limited as long as it can promote the crystallization of the (A) component. For example, inorganic substances such as boron nitride, titanium oxide, talc, layered silicate, calcium carbonate, sodium chloride, and metal phosphate, sugar alcohol compounds derived from natural products such as erythritol, galactitol, mannitol, and arabitol, pentaerythritol, polyvinyl alcohol, chitin, chitosan, polyethylene oxide, aliphatic carboxylic acid amides, aliphatic carboxylic acid salts, aliphatic alcohols, aliphatic carboxylic acid esters, dimethyl adipate, dibutyl adipate, diisodecyl adipate, and dibutyl sebacate are usable. Examples of such compounds include dicarboxylic acid derivatives, cyclic compounds having C=O and a functional group selected from NH, S, and O in the molecule, such as indigo, quinacridone, and quinacridone magenta, sorbitol derivatives such as sorbitol, bisbenzylidene sorbitol, and bis(p-methylbenzylidene)sorbitol, compounds containing a nitrogen-containing heteroaromatic nucleus, such as pyridine, triazine, and imidazole, phosphoric acid ester compounds, bisamides of higher fatty acids and metal salts of higher fatty acids, branched polylactic acid, and low molecular weight poly(3-hydroxybutyric acid). These compounds may be used alone or in combination of two or more.

[0063] [Plasticizer] The type of plasticizer is not particularly limited. For example, modified glycerin compounds such as glycerin, glycerin diacetomonolaurate, glycerin diacetomonocaprylate, and glycerin diacetomonodecanoate, adipate compounds such as diethylhexyl adipate, dioctyl adipate, and diisononyl adipate, polyether ester compounds such as polyethylene glycol dibenzoate, polyethylene glycol dicaprylate, and polyethylene glycol diisostearate, benzoate compounds such as benzyl 2(2-methoxyethoxy)ethyl adipate, epoxidized soybean oil, epoxidized fatty acid 2-ethylhexyl, and sebacic acid monoesters can be mentioned. These may be used alone or in combination of two or more.

[0064] [Molding method and uses of molded body]

[0065] The molding method is not particularly limited as long as it is a known blow molding method.

[0066] The use of the molded article is not particularly limited as long as it is an application generally used for hollow blow molded articles, and examples thereof include container bottles for food, beverages, tablets, chemicals, and the like.

[0067] The hollow blow molded article is preferably a multi-layer hollow blow molded article having a layer of a plant-derived polyolefin resin, which is the same as or different from the component (A), laminated on the inner surface. The multi-layer hollow blow molded article contains a chemically stable inner layer (a plant-derived polyolefin resin layer), and therefore can prevent the biomass components contained in the outer layer from being damaged by the contents of the blow molded article, such as food, beverages, tablets, chemicals, and other container bottles. In other words, the resin layer, such as polyethylene or polypropylene, which has a proven track record in terms of food safety, plays a protective role. When various aqueous solutions and oils and fats other than food come into direct contact with the contents of the blow molded article, the biomass components contained in the molded article can be prevented from coming into direct contact with the contents of the blow molded article. EXAMPLES

[0068] The present invention will be specifically described below with reference to test examples, but the present invention is not limited to these. There is none.

[0069] <Preparation of Kneaded Composition Pellet> The (A) resin component and the (B) biomass component were previously dried in a hot air dryer (80 to 100°C, 12 hours), and the moisture content was confirmed and adjusted when weighed, and then thoroughly mixed in a plastic bag in the ratio shown in Table 1. Thereafter, the mixture was extruded in a twin-screw extruder kneader (manufactured by Ikegai Corporation, PCM30) at a set temperature of 180°C and a rotation speed of 100 rpm, and cut to obtain kneaded composition pellets.

[0070] In Table 1, the raw materials are as follows: (A) Resin component Bio-PE: Bio-polyethylene (plant-derived polyolefin resin) / GreenPE "SGF4950" "SHE150" (Braskem, bio-based BB degree 96% (SGF4950), 94% (SHE150)) PBS / PHA composite resin: Composite resin of polybutylene succinate resin and polyhydroxyalkanoate (plant-derived polyolefin resin), BB degree 53% LLDPE: Low density polyethylene (synthetic polyolefin resin) / UJ960 (Japan Polyethylene Co., Ltd.), BB degree 0% PP: Polypropylene (synthetic polyolefin resin), BB degree 0% (B) Biomass components (all BB content 100%) Starch (spiral molecular structure) Examples 1 to 3: Potato starch (product name: ST Starch P, Nippon Starch Chemical Co., Ltd., primary average particle size: about 35 μm) Example 4: Hydroxypropyl starch (product name: HP Starch G-800, Nippon Starch Chemical Co., Ltd., average primary particle size: about 20 μm) Wood flour: Commercially available mixed cypress and cedar wood flour (non-spiral structure) / 100 mesh Cellulose (non-helical structure): ARBOCEL BE600-30 (Rettenmeyer) (C) Additives Compatibilizer: Maleic anhydride modified polypropylene (PP) / UMEX 1001 (Sanyo Chemical Industries, Ltd., BB degree 0%) Viscosity modifier: Low viscosity polypropylene (PP) / Elmodu S600 (Idemitsu Kosan Co., Ltd., BB degree 0%) Lubricant: Calcium stearate (Nitto Kasei Kogyo Co., Ltd.), hydrogenated hardened oil BB grade 100%

[0071] <Hollow blow molding> After drying the kneaded composition pellets, a sample hollow bottle with a diameter of 40 mm and a height of 120 mm was molded at Heiwa Chemical Industry Co., Ltd. using a blow molding prototype testing machine designed by the company. Although this molding testing machine is capable of blow molding single or multiple layers, in this test, the blow molding test was performed with two layers of the same thickness ratio, with the inner layer / outer layer materials being changed, with the inner layer being a base resin (component (A)) and the outer layer being a resin composition consisting of the kneaded composition pellets.

[0072] In the molding test, it is necessary to search for suitable conditions while changing temperature conditions, etc., but the main criterion for judgment was whether blow molding is possible or not. In addition, the state of cross-sectional peeling was also confirmed in the case of two layers. The results are shown in Table 1.

[0073] [Table 1] *(C) Additives The compatibilizer was added at 3% of the biomass filler (B). The viscosity modifier was added in an amount of 10% of the bio-PE in Examples 1 and 2. The lubricant in Example 4 was added at 1% of the total amount.

[0074] From the compositions in the Examples, good hollow blow molded articles were obtained. In particular, in Examples 1 to 3, the bio-based content of the compositions exceeded 95%. In Examples 2 and 3, the mass ratio of the solid content of component (A) to component (B) was in the range of 40:60 to 50:50, with the biomass component accounting for the majority, and the hollow blow molded articles were made of true biomass classified materials that went beyond the classification of plastic materials and were on a higher level than the plastic resource circulation strategy aimed for by the country.

[0075] On the other hand, the comparative examples did not have sufficient blow moldability, and cracks and breaks occurred, making it impossible to obtain a stable hollow blow molded article. In general, as the content of the biomass-derived component (component (B)) increases, the brittleness and hardness of the composition itself becomes significant, and even if it can withstand injection molding or thick sheet molding, in the case of blow molding, air is blown into the molten resin from the inside to inflate and mold it, so if the biomass powder is at a high concentration, it cannot withstand the blowing of air, the molten resin cracks, and a blow molded product could not be obtained. It is believed that this is the reason why good blow molded articles were obtained in Reference Examples 1 to 3, but not in Comparative Examples 1 and 2.

[0076] On the other hand, it is believed that Examples 1 to 4 exhibited peculiar behavior due to the helical molecular structure of the biomass component, and thus were able to perform blow molding even when a large amount of the biomass component was added.

Claims

1. (A) a thermoplastic resin; (B) a biomass component having a helical molecular structure; The total mass of the solid contents of the (A) component and the (B) component is 90 parts by mass or more per 100 parts by mass of the molded body, the mass ratio of the solid content of the component (A) to the component (B) is within the range of 40:60 to 70:30; A hollow blow molded article having a bio-based content of 60% or more.

2. The hollow blow molded article according to claim 1, wherein the component (A) is a bio-polyethylene resin.

3. The hollow blow molded body made of the biomass classification material according to claim 1, wherein the mass ratio of the solid content of the (A) component to the (B) component is within the range of 40:60 to 50:

50.

4. The hollow blow molded article according to claim 1, wherein the bio-based content is 90% or more.

5. 2. The hollow blow molded article according to claim 1, further comprising an inner surface layer formed with a layer of a thermoplastic resin which is the same as or different from the component (A).

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