JP2022034985A - Manufacturing method of rotary molded product, rotary molded product and molding material for rotary molding - Google Patents

Abstract

To provide a method capable of easily producing a molded product in which additives are unevenly distributed in an inner surface side.SOLUTION: The method of manufacturing a rotary molded product includes a step of dry blending a powder of a thermoplastic resin and functional fine particles to obtain a molding material, and a step of rotary molding the molding material.SELECTED DRAWING: Figure 1

Description

There is an application for application of Article 30, Paragraph 2 of the Patent Act ・ May 19, 2020 https: // www. youtube. com / watch? Published on v = QsyyV1d2daM ・ May 21, 2020 Published on the leaflet of "REOD-100L >> Industry's First! Antistatic Container" ・ June 1, 2020 http: // www. e-suiko. co. jp / http: // www. e-suiko. co. jp / news / 4162 / http: // www. e-suiko. co. Published on jp / product / 4146 /

The present disclosure relates to a method for producing a rotary molded body, a rotary molded body and a molding material for rotary molding, and more particularly, a method for manufacturing a rotary molded body including a dry blending step and a rotary molding step, a thermoplastic resin and functional fine particles. The present invention relates to a rotary molded product of a molding material containing, and a molding material for rotary molding containing a dry blend mixture.

A rotary molding method is used as a method for manufacturing hollow products such as containers and tanks. In the rotary molding method, a molded product is manufactured by heating a mold into which a molding material is charged while rotating the mold, adhering the molten molding material to the surface of the mold, and gradually depositing the molded material. The rotary molded body formed by depositing such a molding material has an outer surface which is a surface in contact with the surface of the mold and an inner surface which is a surface opposite to the outer surface of the material forming the molded body. Have.

In rotary molding, when particles such as metal and carbon are contained as an additive in the molded body, in addition to uniformly dispersing the additive in the molded body, the additive is transferred to the outer surface of the molded body by the centrifugal force of the rotary molding. It is known that it can be unevenly distributed on the side (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-157445

However, in containers and the like, it is often required to improve the properties such as conductivity on the inner surface, such as reducing the adhesion of the contents to the inner surface of the container. Therefore, the additive is applied to the outer surface of the molded body. It is required to be more unevenly distributed on the inner surface side than on the side.

An object of the present disclosure is to provide a method capable of easily producing a molded product in which additives are unevenly distributed on the inner surface side.

The method for producing a rotary molded article according to one aspect of the present disclosure includes a step of dry blending a powder of a thermoplastic resin and functional fine particles to obtain a molding material, and a step of rotationally molding the molding material.

The rotary molded body according to one aspect of the present disclosure is a rotary molded body of a molding material containing a thermoplastic resin and functional fine particles. This rotomould has an inner surface and an outer surface. The ratio of the functional fine particles to the thermoplastic resin is larger in the inner surface layer than in the outer surface layer.

The rotary molded body according to one aspect of the present disclosure is a rotary molded body of a molding material containing a thermoplastic resin and functional fine particles. This rotomould has an inner surface and an outer surface. The properties derived from the functional fine particles are higher on the inner surface than on the outer surface.

The molding material for rotary molding according to one aspect of the present disclosure includes a dry blend mixture of a powder of a thermoplastic resin and functional fine particles.

According to the present disclosure, it is possible to provide a method capable of easily producing a molded product in which additives are unevenly distributed on the inner surface side.

FIG. 1 is a schematic perspective view showing an example of a rotary molded body according to an embodiment of the present disclosure. FIG. 2 is a schematic horizontal sectional view of the same rotary molded body. FIG. 3 is an optical micrograph of a part of the same rotary molded body.

1. 1. Outline The method for manufacturing a rotary molded article of the present embodiment includes a step of dry-blending a powder of a thermoplastic resin and functional fine particles to obtain a molding material (hereinafter, also referred to as a dry blending step) and rotating the molding material. It includes a molding process (hereinafter, also referred to as a rotary molding process).

According to the manufacturing method of the present embodiment, by performing dry blending and rotary molding, it is possible to easily manufacture a molded product in which functional fine particles as additives are unevenly distributed on the inner surface side. The reason why the molded product in which the functional fine particles are unevenly distributed on the inner surface side can be obtained by the production method of the present embodiment is not necessarily clear, but can be inferred as follows, for example. By adopting rotary molding as the molding method of the molded body and using a dry blend mixture of the thermoplastic resin powder and the functional fine particles as the molding material used for the rotary molding, the thermoplastic resin and the functional fine particles can be obtained. Unlike the case where the kneaded product of No. 1 is used as the molding material, the functional fine particles are not immediately uniformly dispersed in the thermoplastic resin in the molding process, and on the outer surface side in contact with the mold in which the molded body is first formed. Although the ratio of functional fine particles to the thermoplastic resin is small, it is considered that this ratio increases as the molding progresses toward the inner surface side. As a result, a molded body in which the functional fine particles are unevenly distributed on the inner surface side of the molded body is formed.

2. 2. Details Hereinafter, the method for manufacturing the rotary molded body of the present embodiment, the rotary molded body obtained by this manufacturing method, and the molding material for rotary molding used in this manufacturing method will be described in detail.

<Manufacturing method of rotary molded body>
As described above, the manufacturing method of the present embodiment includes a dry blending step and a rotary molding step. Hereinafter, each step will be described.

[Dry blend process]
In this step, a thermoplastic resin powder and functional fine particles are dry-blended to obtain a molding material. "Dry blending" means that two or more kinds of materials are directly mixed and mixed (dry mixing) without melting and without using a medium such as a solvent.

(Thermoplastic resin powder)
Examples of the thermoplastic resin include polyethylene, polypropylene, and polyolefins such as copolymers of ethylene with α-olefins such as 1-butene and 1-octene; vinyl resins such as vinyl acetate, polyvinyl chloride and polyvinyl alcohol; polyamides. 66, Polypropylene such as Polypolymer 6; Polypropylene; Polyphenylene sulfide; Polyoxymethylene; Polyethylene terephthalate, Polybutylene terephthalate and other polyesters; Polystyrene; Polyacrylonitrile-butadiene-styrene copolymer and other styrene copolymers; Polycarbonate; Polyether ether Examples thereof include ketones; acrylic resins such as polymethyl methacrylate; and fluororesins.

In the present embodiment, the thermoplastic resin preferably contains one or more resins selected from the group consisting of polyethylene, acrylonitrile-butadiene-styrene copolymer, and acrylic resin, and particularly preferably contains polyethylene. Polyethylene is lightweight, does not easily generate toxic gas even when incinerated, is easy to recycle, has excellent oil resistance and chemical resistance, and has excellent impact strength. Examples of polyethylene include linear low-density polyethylene, side-chain branched low-density polyethylene, medium-density polyethylene, high-density polyethylene and the like.

The fluidity (MFR: Melt Flow Rate) defined by JIS-K7210 of the thermoplastic resin is preferably 2.5 g / 10 min or more. In this case, the fluidity of the molten molding material can be ensured at the time of molding, and the surface shape of the rotary molded body can be further improved. The upper limit of the MFR of the thermoplastic resin is not particularly limited, but is, for example, 50 g / 10 min.

The shape of the thermoplastic resin powder is, for example, spherical shape, egg shape, spindle shape, hollow shape, amorphous shape, chain shape, needle shape, columnar shape, rod shape, flat shape, scaly shape, leaf shape, tube shape, etc. Sheets and the like can be mentioned.

The particle size of the powder of the thermoplastic resin is preferably 100 μm or more and 1500 μm or less, more preferably 300 μm or more and 1300 μm or less, and further preferably 500 μm or more and 1000 μm or less. The particle size of the powder is, for example, a median diameter measured by a particle size distribution measuring device (SALD-2300, manufactured by Shimadzu Corporation).

The thermoplastic resin powder can be obtained, for example, by pulverizing the pellets of the thermoplastic resin. The pulverization method is not particularly limited, but a known pulverization method such as a mechanical pulverization method or a freezing pulverization method can be used. The thermoplastic resin may be a new product, a recycled product, or a mixture thereof.

(Functional fine particles)
The "functional fine particles" refer to fine particles added for imparting or improving functionality such as conductivity and antibacterial properties of a molded product. It is preferable that the functional fine particles have a melting point of 60 ° C. or higher or have no melting point. By using such functional fine particles, the functional fine particles can be more unevenly distributed on the inner surface side of the molded product.

Examples of the functional fine particles include conductive fine particles, insulating fine particles, heat conductive fine particles, heat insulating fine particles, sound absorbing fine particles, electromagnetic wave absorbing fine particles, flame-retardant fine particles, colored fine particles, reinforcing fine particles, and antibacterial fine particles. Antifouling fine particles and the like can be mentioned.

Examples of the conductive fine particles include carbon particles such as carbon black, carbon nanotubes, fullerene, and graphite; gold, silver, copper, nickel, chromium, palladium, rhodium, ruthenium, indium, aluminum, tungsten, molybdenum, platinum, and copper-nickel. Metal particles such as alloys, silver-palladium alloys, copper-tin alloys, silver-copper alloys, copper-manganese alloys, these fine particles coated with silver or the like; silver oxide, indium oxide, tin oxide, zinc oxide , Conductive oxide particles such as ruthenium oxide, titanium oxide, antimony-containing tin oxide, and tin-containing indium oxide.

Examples of the insulating fine particles include inorganic particles such as glass, silica, alumina, titania, clay, zeolite, silicon nitride, boron nitride and calcium oxide; and resin particles such as acrylic resin, polyamide resin and polyacetal resin.

Examples of the heat conductive fine particles include metal particles such as gold, silver, copper, iron, nickel, tin, aluminum, cobalt, indium, and alloys thereof; metal oxide particles such as aluminum oxide, magnesium oxide, and titanium oxide; nitrided particles. Examples thereof include metal nitride particles such as boron and aluminum nitride; carbon particles such as graphite and diamond; and metal-coated particles obtained by coating resin particles with a metal layer.

Examples of the heat insulating fine particles include inorganic or organic hollow fillers, beads; particles such as silica.

Examples of the sound-absorbing fine particles include particles such as barium sulfate, silica, shirasu balloon, and vermiculite.

Examples of the electromagnetic wave absorbing fine particles include carbonyl iron and various ferrites (manganese-zinc-based, nickel-zinc-based, nickel-zinc-copper-based, copper-zinc-based, magnesium-manganese-based, copper-magnesium-manganese-based, neodymium-. Iron-boron system, etc.).

Examples of the flame-retardant fine particles include red phosphorus-based compound particles, phosphazene-based compound particles, melamine-based resin particles, titanium oxide-silicon oxide composite particles, and the like.

Examples of the coloring fine particles include pigments, colored aggregates, colored resin particles, colored gel particles and the like.

Examples of the reinforcing fine particles include ceramic particles such as zirconia, barium titanate, and hydroxyapatite; metal oxide particles such as aluminum oxide; and diamond particles.

Examples of the antibacterial fine particles include particles containing metal elements such as silver, copper, zinc, gold, titanium, cobalt, tungsten, tin, bismuth, chromium, nickel, and tarium; known antibacterial compounds such as silver ions, or oxidation. Examples thereof include particles obtained by atomizing or supporting a photocatalyst such as titanium.

Examples of the antifouling fine particles include inorganic copper compound particles such as a copper compound and a cuprous oxide compound; particles obtained by atomizing or carrying a known antifouling compound.

In the present embodiment, the antibacterial fine particles preferably contain at least one selected from the group consisting of conductive fine particles and antibacterial fine particles.

The shapes of the functional fine particles include, for example, spherical shape, egg shape, spindle shape, hollow shape, amorphous shape, chain shape, needle shape, columnar shape, rod shape, flat shape, scale shape, leaf shape, tube shape, sheet shape and the like. Can be mentioned.

The average particle size of the functional fine particles is preferably 0.01 μm or more, more preferably 0.03 μm or more. In this case, the functional fine particles can be unevenly distributed on the inner surface side of the molded product. The average particle size is preferably 100 μm or less, and more preferably 10 μm or less. In this case, the uneven distribution of the functional fine particles can be made more uniform. The particle size of the functional fine particles is, for example, a median diameter measured by a particle size distribution measuring device (SALD-2300, manufactured by Shimadzu Corporation). The functional fine particles may be those in which primary particles are aggregated with each other to form secondary particles or structures.

(Dry blend method)
By dry blending the powder of the thermoplastic resin and the functional fine particles, a dry blend mixture which is a molding material for rotary molding is obtained. The dry blending method is not particularly limited, and examples thereof include a method of mixing using a closed mixer such as a tumbler mixer, a ribbon mixer, a nouter mixer, and a ribocorn mixer. The temperature at the time of dry blending is usually normal temperature or higher and 60 ° C. or lower. The time for performing the dry blend is usually 1 minute or more and 6 hours or less, preferably 5 minutes or more and 3 hours or less, more preferably 10 minutes or more and 2 hours or less, and 20 minutes or more and 60 minutes or less. Is particularly preferred.

The ratio of the functional fine particles to 100 parts by mass of the powder of the thermoplastic resin is preferably 0.01 parts by mass or more. In this case, the characteristics on the inner surface of the molded product can be further improved. This ratio is more preferably 0.05 parts by mass or more, further preferably 0.1 parts by mass or more, and particularly preferably 0.15 parts by mass or more. The ratio of the functional fine particles is preferably 1 part by mass or less. In this case, the peeling of the functional fine particles from the inner surface of the molded product can be further reduced. This ratio is more preferably 0.7 parts by mass or less, further preferably 0.4 parts by mass or less, and particularly preferably 0.3 parts by mass or less.

To the extent that the effects of the present disclosure are not impaired, components other than the thermoplastic resin powder and the functional fine particles are mixed with at least one of the thermoplastic resin powder and the functional fine particles before the dry blend. It may be mixed at the time of dry blending. The other components may be in the form of particles or may be liquid or the like. Examples of other components include ultraviolet absorbers, stabilizers, antioxidants, compatibilizers, dispersants, mold release agents and the like.

The dry blend mixture of the thermoplastic resin and the functional fine particles obtained in the dry blending step can be suitably used as a molding material for rotary molding.

[Rotating molding process]
In this step, the molding material obtained in the dry blending step (hereinafter, also referred to as molding material (X)) is rotationally molded.

In this step, first, the molding material (X) is put into the mold. Next, the mold is heated while rotating. As the temperature of the mold rises, the molding material (X) melts. The molten molding material (X) adheres to the mold surface and gradually accumulates. After heating the mold for a certain period of time, the mold is cooled and the molded product is taken out from the mold. In this way, a rotary molded body of the molding material (X) is obtained.

In the present embodiment, the mold temperature at the time of performing rotary molding is appropriately set according to the type of the thermoplastic resin, but is preferably 150 ° C. or higher and 300 ° C. or lower, and 180 ° C. or higher and 280 ° C. or lower. Is more preferable. Further, in the present embodiment, the heating time for rotary molding is preferably 5 minutes or more and 60 minutes or less, and more preferably 10 minutes or more and 35 minutes or less. Examples of the heating method in rotary molding include a direct flame type, a hot air circulation oven type, and a medium circulation type.

In the present embodiment, it is possible to manufacture molded bodies having various shapes and dimensions such as containers, tanks, cases, boxes, etc., depending on the shape of the mold. The rotation method in the rotary molding may be uniaxial rotation or biaxial rotation, or may be a method in which uniaxial rotation and oscillating motion are combined, depending on the shape and the like of the rotary molded body to be manufactured.

FIG. 1 shows an example of a rotary molded product obtained by the manufacturing method of the present embodiment. FIG. 2 is a horizontal sectional view of the container which is the rotary molded body 1 of FIG. The rotary molded body 1 has an inner surface 2 and an outer surface 3. In the rotary molded body 1 obtained by the manufacturing method of the present embodiment, the mold surface side of the rotary molding is the outer surface 3, and the surface side opposite to the mold is the inner surface 2.

The wall thickness of the rotary molded body 1 is preferably 0.5 mm or more and 30 mm or less, more preferably 1 mm or more and 20 mm or less, further preferably 2 mm or more and 10 mm or less, and 3 mm or more and 8 mm or less. Is particularly preferable.

In the rotary molded body 1, the functional fine particles are unevenly distributed on the inner surface side. That is, in the rotary molded body 1, the ratio of the functional fine particles to the thermoplastic resin is larger in the surface layer of the inner surface 2 than in the surface layer of the outer surface 3. The surface layer means a region near the surface of the rotary molded body 1, such as the inner surface 2 and the outer surface 3, and for example, a region from the surface of the rotary molded body 1 to a depth of 100 μm, preferably a region from the surface to a depth of 10 μm. say.

In the rotary molded body 1, the ratio of the functional fine particles to the thermoplastic resin (hereinafter, also referred to as the ratio (Y)) is the ratio (Y) (inner surface 2) of the inner surface 2 to the ratio (Y) in the surface layer of the outer surface 3. The multiple of the ratio (Y) in the surface layer / the ratio (Y) in the surface layer of the outer surface 3 is preferably 1.1 times or more, more preferably 1.5 times or more, and more preferably 2 times or more. Is more preferable, and 3 times or more is particularly preferable. The upper limit of this multiple is not particularly limited, but is, for example, 10 times.

Due to the uneven distribution of the functional fine particles described above, in the rotary molded body 1, the characteristics derived from the functional fine particles are higher on the inner surface 2 than on the outer surface 3. The characteristics derived from the functional fine particles are, for example, conductive for conductive fine particles and antibacterial for antibacterial fine particles.

In the rotary molded body 1, a multiple of the characteristic value on the inner surface (characteristic value (Z) on the inner surface 2 / characteristic value (Z) on the outer surface 3) with respect to the characteristic value on the outer surface 3 (hereinafter, also referred to as the characteristic value (Z)). Is preferably 2 times or more, more preferably 5 times or more, further preferably 10 times or more, and particularly preferably 100 times or more. The upper limit of this multiple is not particularly limited, but is, for example, 10 to ¹⁰ times.

When the functional fine particles are conductive fine particles, the surface resistivity corresponding to the conductivity on the surface of the rotary molded body 1 is preferably 1 × 10 ¹² Ω or less on the inner surface 2. In this case, it is possible to further prevent the contents of the rotary molded body 1 from adhering to the inner surface 2. The surface resistivity of the inner surface 2 is more preferably 1 × 10 ¹⁰ Ω or less, further preferably 1 × 10 ⁹ Ω or less, and particularly preferably 1 × 10 ⁸ Ω or less. The lower limit of the surface resistivity is not particularly limited, but is, for example, ¹ × 105 Ω. The surface resistivity of the outer surface 3 is preferably 1 × 10 ¹³ Ω or more. The surface resistivity is a value measured by a method according to JIS-K6911: 2006.

When the functional fine particles are antibacterial fine particles, the antibacterial activity value indicating the antibacterial property on the surface of the rotary molded body 1 is preferably 2.0 or more on the inner surface 2. In this case, it is possible to further suppress an increase in the number of viable cells on the inner surface of the rotary molded body 1. The antibacterial activity value is more preferably 2.5 or more, further preferably 3.0 or more, and particularly preferably 4.0 or more. The upper limit of the antibacterial activity value is not particularly limited, but is, for example, 8.0. The antibacterial activity value on the outer surface 3 is, for example, 1.0 or more and less than 2.0. The antibacterial activity value is a value measured by a method according to JIS-Z2801: 2012.

In the rotary molded product of the present embodiment, the functional fine particles are unevenly distributed on the inner surface side by using the above-mentioned manufacturing method, and the characteristics derived from the functional fine particles are higher on the inner surface than on the outer surface.

1. 1. Manufacture of a container containing conductive fine particles [Example 1]
(Dry blend process)
100 parts by mass of polyethylene powder and 0.2 parts by mass of carbon black (manufactured by Tokyo Ink Co., Ltd., product number PM-905H-BLK), which is a conductive fine particle, are mixed by using a ribbon mixer to dry blend and dry. A blend mixture was obtained and used as a molding material A.

(Rotating molding process)
The molding material A obtained in the dry blending step was put into a mold of a rotary molding machine and molded by a rotary molding method to produce a hollow cylindrical container having a wall thickness of 4.5 mm. The set heating temperature was 250 ° C to 300 ° C, and the set heating time was 15 minutes.

[Comparative Example 1]
By mixing 100 parts by mass of polyethylene pellets and 0.2 parts by mass of carbon black (manufactured by Tokyo Ink Co., Ltd., product number PM-905H-BLK), kneading with an extruder, and then pulverizing with a fine pulverizer. , A molding material B was obtained. Using this molding material B, a container having the same shape and dimensions was manufactured under the same rotational molding conditions as in Example 1.

(Measurement of surface resistivity)
As an evaluation of the conductivity of the inner and outer surfaces of the rotary molded body, the surface resistivity of each of the inner and outer surfaces was set to a test voltage of 500 V or 5 V by a method based on JIS-K6911: 2006 (general test method for thermosetting plastics). The measurement was performed under the condition that the charging time was 1 minute. The measurement results are shown in Table 1.

From the results in Table 1, the surface resistivity of the comparative example is about the same on the inner surface and the outer surface, whereas the surface resistivity of the example is ¹⁰⁸ times that of the inner surface on the outer surface. It was shown that the inner surface of the rotary molded body is more conductive than the outer surface.

(Structural analysis of rotary molded product)
A sample prepared by cutting out a part including the inner surface and the outer surface of the rotary molded body obtained in Example 1 was observed with an optical microscope at a magnification of 40 times, and the structural analysis of the rotary molded body was performed. A photomicrograph is shown in FIG. In the sample of FIG. 3, the right side surface is the outer surface and the left side surface is the inner surface. In the surface layer on the outer surface (right side), the ratio of carbon black (black) to polyethylene (colorless) is small, whereas in the surface layer on the inner surface (left side), the ratio of carbon black to polyethylene is large. This is considered to be related to the production by rotary molding. Also, polyethylene and carbon black are not uniformly mixed, and most of carbon black is present in the gaps of multiple regions due to the polyethylene powder, and the rotomould is locally formed. It forms a structure including a portion where the abundance ratio of carbon black is large. This is believed to be related to the production with a dry blend mixture of polyethylene and carbon black.

2. 2. Production of container containing antibacterial fine particles [Example 2]
(Dry blend process)
100 parts by mass of polyethylene powder and 0.5 parts by mass of an antibacterial agent (manufactured by Fuji Chemical Co., Ltd., product name Bactekiller, product number BM-102JG), which is an antibacterial fine particle, are put together in a tumbler mixer and mixed to dry blend. A dry blend mixture was obtained and used as a molding material C.

(Rotating molding process)
The molding material C obtained in the dry blending step was put into a mold of a rotary molding machine and molded by a rotary molding method to produce a hollow prismatic shape with a wall thickness of 3.0 mm. The set heating temperature was 280 ° C., and the set heating time was 14 minutes.

[Comparative Example 2]
100 parts by mass of polyethylene pellets and 0.5 parts by mass of an antibacterial agent (manufactured by Fuji Chemical Co., Ltd., product name Bactekiller, product number BM-102JG), which is an antibacterial fine particle, are mixed, kneaded with an extruder, and then finely pulverized. The molding material E was obtained by pulverizing with a machine. Using this molding material E, a container having the same shape and dimensions was manufactured under the same rotational molding conditions as in Example 1.

(Measurement of antibacterial activity value)
As an evaluation of the antibacterial properties of the inner and outer surfaces of the rotary molded body, the antibacterial activity values of the inner and outer surfaces were set to yellow grapes by a method based on JIS-Z2801: 2012 (antibacterial processed product-antibacterial test method / antibacterial effect). Measured for cocci. That is, the bacterial solution prepared in 1/500 ordinary bouillon was dropped on the surface of the test piece, adhered with a film and stored at 35 ° C., and then the viable cell count was measured for the bacterial solution on the test piece. The antibacterial activity value was calculated by the following formula.
Antibacterial activity value = (Common logarithmic value of viable cell count after 24 hours in unprocessed test piece)-(Common logarithmic value of viable cell count after 24 hours in test piece)

From the results in Table 2, the antibacterial activity value of the comparative example is about the same on the inner surface and the outer surface, whereas the antibacterial activity value of the example is 1.0 larger on the inner surface than the outer surface. It was shown that in the rotary molded body, the inner surface has higher antibacterial property than the outer surface.

1 Rotating molded body 2 Inner surface 3 Outer surface

Claims (12)

The process of dry blending thermoplastic resin powder and functional fine particles to obtain a molding material,
A method for manufacturing a rotary molded body, comprising a step of rotary molding the molding material. The method for manufacturing a rotary molded body according to claim 1, wherein the rotary molded body includes a container. The method for producing a rotary molded article according to claim 1 or 2, wherein the functional fine particles include at least one selected from the group consisting of conductive fine particles and antibacterial fine particles. The method for producing a rotary molded product according to any one of claims 1 to 3, wherein the thermoplastic resin contains polyethylene. A rotary molded body of a molding material containing a thermoplastic resin and functional fine particles.
It has an inner surface and an outer surface,
A rotary molded product in which the ratio of functional fine particles to the thermoplastic resin is larger in the inner surface layer than in the outer surface layer. The rotary molded product according to claim 5, wherein the functional fine particles include at least one selected from the group consisting of conductive fine particles and antibacterial fine particles. A rotary molded body of a molding material containing a thermoplastic resin and functional fine particles.
It has an inner surface and an outer surface,
A rotation-molded article having properties derived from the functional fine particles higher on the inner surface than on the outer surface. The rotary molded article according to claim 7, wherein the property comprises at least one selected from the group consisting of conductive and antibacterial properties. The rotary molded product according to any one of claims 5 to 8, wherein the molding material contains a dry blend mixture of the powder of the thermoplastic resin and the functional fine particles. The rotary molded body according to any one of claims 5 to 9, which includes a container. The rotary molded product according to any one of claims 5 to 10, wherein the thermoplastic resin contains polyethylene. A molding material for rotary molding containing a dry blend mixture of thermoplastic resin powder and functional fine particles.

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