container

Abstract

An object of the present invention is to provide a technology capable of suppressing the intrusion of impurities into the contents of a container densely filled with inorganic powder. [Solution] The present invention provides a container comprising a container body having an opening and a lid that closes the opening, the opening having a first threaded portion formed therein, the lid having a second threaded portion that threadably engages with the first threaded portion, the first threaded portion and the second threaded portion containing inorganic substance powder and thermoplastic resin, the content of the inorganic substance powder being more than 50.0 mass% and not more than 80.0 mass% of the entire container, and the inorganic substance powder satisfying all specified requirements.

Description

[Technical field]

[0001] The present invention relates to a container. [Background technology]

[0002] In recent years, from the viewpoint of reducing the environmental load, etc., attempts have been made to highly fill resin molded articles with inorganic powders (for example, Patent Document 1). Resin molded products highly filled with inorganic powder generally have superior mechanical properties compared to resin alone. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-158560 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the present inventors have found that while containers highly filled with inorganic powder have excellent strength, the threaded portion (usually the threads) between the container body and the lid is prone to chipping. In particular, it was found that if a load is applied when the lid is not completely closed (i.e., the screw connection between the container body and the lid is incomplete), the threads can easily be damaged. Fragments and the like generated by breakage of the screw threads can impair the quality of the contents of the container.

[0005] The fragments contain impurities such as lead contained in inorganic powder, and improvements are needed from a safety standpoint.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique capable of suppressing the intrusion of impurities into the contents of a container densely filled with inorganic substance powder. [Means for solving the problem]

[0007] The present inventors have found that the above-mentioned problems can be solved by blending an inorganic substance powder that satisfies a predetermined requirement for the content of trace components in a container that is highly packed with an inorganic substance powder, and have completed the present invention. More specifically, the present invention provides the following.

[0008] (1) A container comprising: The container comprises a container body having an opening and a lid for closing the opening, the opening includes a first threaded portion; the lid includes a second screw portion that is screwed into the first screw portion, the first screw-type portion and the second screw-type portion contain an inorganic powder and a thermoplastic resin; The content of the inorganic substance powder is more than 50.0 mass% and 80.0 mass% or less with respect to the entire container, A container in which the inorganic powder satisfies all of the following requirements: (Requirement 1) The lead content per gram of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is taken as 100% by mass, the total amount of alkali metal and magnesium is 1.0% by mass or less.

[0009] (2) The container described in (1), wherein the inorganic substance powder includes calcium carbonate.

[0010] (3) The container according to (2), wherein the calcium carbonate comprises ground calcium carbonate.

[0011] (4) The container according to (1), wherein the inorganic powder further satisfies the following requirements: (Requirement 3) The arsenic content per gram of the inorganic substance powder is 3 μg or less.

[0012] (5) The container according to (3), wherein the ground calcium carbonate contains ground calcium carbonate having an average particle size of 0.7 μm or more and 6.0 μm or less as measured by an air permeability test in accordance with JIS M-8511.

[0013] (6) The container described in (1), wherein the thermoplastic resin includes a polypropylene-based resin and / or a polyethylene-based resin.

[0014] (7) The container according to (6), wherein the polyethylene resin comprises high density polyethylene and / or linear low density polyethylene.

[0015] (8) The container according to (6), wherein the polypropylene-based resin comprises a polypropylene homopolymer and / or a polypropylene block polymer.

[0016] (9) The container according to (1), wherein the container is obtained by injection molding or compression molding.

[0017] (10) The container according to (1), which is a pharmaceutical container.

[0018] (11) The container according to (1), which is a cosmetic container. Effect of the Invention

[0019] According to the present invention, a technique is provided that can suppress the intrusion of impurities into the contents of a container that is densely filled with inorganic powder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described, but the present invention is not limited thereto.

[0021] <Container> A container according to one embodiment of the present invention can satisfy all of the following requirements. The container comprises a container body having an opening and a lid for closing the opening. The opening includes a first threaded portion. The lid has a second screw portion that is screwed into the first screw portion. The first and second screw portions include an inorganic powder and a thermoplastic resin. The content of inorganic powder is more than 50.0% by mass and 80.0% by mass or less based on the entire container. The inorganic powder meets all of the following requirements: (Requirement 1) The lead content per gram of inorganic powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is taken as 100% by mass, the total amount of alkali metal and magnesium is 1.0% by mass or less.

[0022] Inorganic powder is known to have the effect of imparting mechanical properties to resin products. For example, the higher the content of inorganic powder, the easier it is to improve drop impact resistance. However, the inventor has discovered that for containers in which the lid and body are fitted together by screws, the higher the content of inorganic powder, the more likely the threads are to break, even though the mechanical properties of the entire container are good. In particular, if the lid is not completely closed (i.e., the screw engagement between the container body and the lid is incomplete), and a load is applied in the vertical direction to the lid, the threads can easily be damaged. This can be said to be a new problem specific to containers that are highly packed with inorganic powder.

[0023] On the other hand, fragments generated by the breakage of the screw threads may impair the quality of the contents of the container (e.g., medicines, cosmetics, etc.). In particular, it is necessary to avoid the mixing of impurities such as lead contained in inorganic powder into the contents.

[0024] In addition, in a container with a low content of inorganic powder (for example, the content of inorganic powder is 50.0 mass % or less relative to the container), damage to the thread is unlikely to occur in the first place, and the above-mentioned problem of the present invention does not exist.

[0025] In one embodiment of the present invention, "consisting of component A" means that the composition is substantially free of components other than component A. In one embodiment of the present invention, "substantially free of component B" includes, for example, an embodiment in which component B is not included at all.

[0026] The configuration of a container according to one embodiment of the present invention will be described in detail below.

[0027] (1) Container structure In one embodiment of the present invention, the container comprises a container body having an opening and a lid for closing the opening. The opening has a first screw-threaded portion. The lid has a second screw-threaded portion that is screwed into the first screw-threaded portion. Such containers include, for example, what may be referred to as screw-on lid containers and the like.

[0028] The "container body" of a container is the portion that provides the space in which the contents of the container are stored. The shape and size of the container body can be appropriately set depending on the use of the container, etc.

[0029] The "opening" of a container is a portion through which things are put in and taken out of the container, and is usually provided at one location on the container body. The shape and size of the opening can be appropriately set depending on the use of the container, etc.

[0030] The "lid" of a container is a part used to seal the opening of the container body. The shape and size of the lid can be appropriately set depending on the shape and size of the opening.

[0031] The opening and the lid each have a screw thread formed in the screw portion, and are configured to be screwed together. The term "screwed engagement" includes screwing the container body and the lid together by interlocking the threads. The term "threaded portion" includes the portion of the container body and the lid that includes the thread and the surface on which the thread is provided. For example, the threaded portion of the container body may be the entire portion called the neck (the portion on which the thread is provided). The threaded portion of the lid may be the entire portion of the container body that is parallel to the neck.

[0032] The shape and size of the container are not particularly limited. For example, the container may be in any shape, such as a cylinder, a bottle, a wide-mouth, a jar, etc.

[0033] The composition of the container is not particularly limited, except that the first threaded portion and the second threaded portion each contain an inorganic powder and a thermoplastic resin.

[0034] The types and amounts of the inorganic powder and thermoplastic resin blended in the container body and the lid may be the same or different.

[0035] The present invention encompasses all of the following aspects. The first screw portion and the second screw portion have the same composition. The entire container body has the same composition. The entire lid is of the same composition. The entire container body and lid are of the same composition.

[0036] From the viewpoint of economy and the like, a preferred embodiment of the present invention includes an embodiment in which the entire container body and the entire lid have the same composition.

[0037] The dimensions of each part of the container can be appropriately set depending on the shape of the container to be used, etc. For example, one embodiment of the present invention includes a container that satisfies the following dimensions.

[0038] [Container body dimensions] Body diameter: 20~150mm Height: 10~150mm Thread diameter: 20~150mm Thread height: 1~5mm Neck length (where the thread is located): 20mm

[0039] [Lid dimensions] Lid outer diameter: 20~150mm Height: 10~50mm Thread height: 1~5mm

[0040] (2)Thermoplastic resin The thermoplastic resin constituting the container and the screwing portion is not particularly limited, and any resin that can be usually blended in resin molded products can be used. The thermoplastic resin may be used alone or in combination of two or more kinds.

[0041] (2-1) Types of thermoplastic resins The thermoplastic resin is not particularly limited, but from the viewpoint of moldability, etc., examples of the thermoplastic resin include polyolefin-based resins, polyester-based resins, polystyrene-based resins, etc.

[0042] In one embodiment of the present invention, the thermoplastic resin preferably comprises a polyolefin-based resin, and more preferably consists of a polyolefin-based resin. In one embodiment of the present invention, the term "polyolefin-based resin" refers to a polyolefin-based resin containing an olefin component unit as a main component. "Containing olefin component units as a main component" means that the olefin component units account for 50 mass % or more (preferably 75 mass % or more, more preferably 85 mass % or more, and even more preferably 90 mass % or more) of the polyolefin resin. The method for producing the polyolefin resin used in the present invention is not particularly limited, and may be any method using a Ziegler-Natta catalyst, a metallocene catalyst, a radical initiator (oxygen, peroxide, etc.), or the like.

[0043] Examples of polyolefin resins include polypropylene resins and polyethylene resins. From the viewpoint of easily preventing damage to the container and easily achieving a good appearance, etc., the thermoplastic resin preferably contains a polypropylene-based resin and / or a polyethylene-based resin, and more preferably consists of a polypropylene-based resin and / or a polyethylene-based resin.

[0044] (2-1-1) Polypropylene resin The polypropylene resin in the present invention includes a resin containing propylene component units in an amount of preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and most preferably 80% by mass or more.

[0045] Examples of polypropylene-based resins include polypropylene homopolymers (propylene homopolymers) and copolymers of propylene and other α-olefins (copolymerizable with propylene). Examples of the "other α-olefins" include α-olefins having 4 to 10 carbon atoms (such as ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1-heptene, and 3-methyl-1-hexene).

[0046] Polypropylene homopolymers include linear or branched polypropylenes exhibiting various stereoregularities (isotactic, syndiotactic, atactic, hemiisotactic, etc.).

[0047] The propylene copolymer may be any of a polypropylene random copolymer (random copolymer), a polypropylene block copolymer (block copolymer), a binary copolymer, a ternary copolymer, etc. Specific examples include an ethylene-propylene random copolymer, a butene-1-propylene random copolymer, an ethylene-butene-1-propylene random terpolymer, an ethylene-propylene block copolymer, etc.

[0048] Among the above polypropylene-based resins, a resin containing a polypropylene homopolymer and / or a polypropylene block polymer is preferred, and a resin made of a polypropylene homopolymer and / or a polypropylene block polymer is more preferred.

[0049] (2-1-2) Polyethylene resin The polyethylene resin in the present invention includes resins containing ethylene component units in an amount of preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and most preferably 80% by mass or more.

[0050] Examples of polyethylene resins include high density polyethylene (HDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), linear low density polyethylene (LLDPE), ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-propylene-butene 1 copolymer, ethylene-butene 1 copolymer, ethylene-hexene 1 copolymer, ethylene-4 methylpentene 1 copolymer, and ethylene-octene 1 copolymer.

[0051] The polyethylene-based resin is preferably a resin containing high-density polyethylene and / or linear low-density polyethylene, and more preferably a resin made of high-density polyethylene and / or linear low-density polyethylene.

[0052] The high density polyethylene preferably has an MFR (190° C., 21.6 kg) according to JIS K 6922-1 (ISO1133) of 5 g / 10 min or more and 15 g / 10 min or less, more preferably 7 g / 10 min or more and 13 g / 10 min or less.

[0053] The linear low density polyethylene preferably has an MFR (190°C, 2.16 kg) according to JIS K 6922-1 (ISO1133) of 0.5 g / 10 min or more and 1.5 g / 10 min or less, and more preferably has an MFR of 0.7 g / 10 min or more and 1.3 g / 10 min or less.

[0054] In a resin containing high density polyethylene and linear low density polyethylene, the mass ratio of the two (high density polyethylene:linear low density polyethylene) is preferably 90:10 to 50:50, more preferably 92:8 to 50:50, and even more preferably 94:6 to 50:50.

[0055] (2-2) Thermoplastic resin content The content of the thermoplastic resin can be appropriately set depending on the blending amount of the inorganic substance powder, etc.

[0056] From the viewpoint of moldability and the like, the content of the thermoplastic resin is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on the entire container.

[0057] The content of the thermoplastic resin is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, of the entire container, from the viewpoint of blending a sufficient amount of inorganic substance powder and imparting strength to the entire container.

[0058] The content of the thermoplastic resin is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, of the threaded portion of the container, from the viewpoint of increasing the flexibility of the threaded portion and making it easier to prevent breakage. It is preferable that either the container body or the screw-on portion of the lid of the container satisfies the above requirements, and it is more preferable that both of them satisfy the requirements.

[0059] The content of the thermoplastic resin is not particularly limited, but is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, relative to the screw portion of the container. It is preferable that either the container body or the screw-on portion of the lid of the container satisfies the above requirements, and it is more preferable that both of them satisfy the requirements.

[0060] (3) Inorganic substance powder The inorganic powder constituting the container or the screw portion is not particularly limited, and any inorganic powder that can be usually blended in resin molded products can be used. The inorganic powder may be used alone or in combination of two or more kinds.

[0061] From the viewpoint of particularly facilitating the solution of the problems specific to the present invention, in one embodiment of the present invention, the inorganic substance powder preferably contains calcium carbonate, and more preferably consists of calcium carbonate. Therefore, in this embodiment, in the following description, "inorganic substance powder" may be appropriately read as "calcium carbonate (preferably ground calcium carbonate)".

[0062] (3-1) Types of inorganic powders Examples of inorganic powders include the following: Carbonates, sulfates, silicates, phosphates, or borates of metals (such as calcium, magnesium, aluminum, titanium, iron, zinc, etc.); Oxides of metals (calcium, magnesium, aluminum, titanium, iron, zinc, etc.); Hydrates of the above salts or oxides.

[0063] Examples of inorganic substance powders include calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, calcium silicate, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium sulfite, sodium sulfate, potassium titanate, bentonite, and graphite.

[0064] The inorganic powder may be synthetic or derived from natural minerals.

[0065] As described above, calcium carbonate is preferred as the inorganic substance powder. The calcium carbonate may be either heavy calcium carbonate or light calcium carbonate, or a combination of these. "Heavy calcium carbonate" is calcium carbonate obtained by mechanically crushing (dry method, wet method, etc.) natural raw materials whose main component is CaCO3 (limestone, etc.). "Light calcium carbonate" is calcium carbonate prepared by a synthetic method (such as chemical precipitation reaction). Thus, ground calcium carbonate and light calcium carbonate are clearly distinguished from each other.

[0066] The difference between ground calcium carbonate and light calcium carbonate can be identified, for example, from the circularity calculated based on the analysis of SEM images. The circularity of heavy calcium carbonate is, for example, in the range of 0.50 to 0.95, and the circularity of light calcium carbonate is, for example, approximately 1.00.

[0067] In one embodiment of the present invention, "circularity" is a value represented by the following formula, and is an index of the degree of irregularity of a particle. The closer the circularity is to "1" (maximum value), the closer it is to a perfect circle, and the lower the value, the higher the degree of irregularity. "Circularity" = (projected area of ​​particle) / (area of ​​circle with the same perimeter as the projected perimeter of the particle)

[0068] Heavy calcium carbonate, due to its manufacturing process, does not have a uniform shape, and is low cost, but it is easy to stably impart good mechanical properties to resin molded products. Therefore, preferred embodiments of the present invention include those in which the calcium carbonate contains ground calcium carbonate and those in which the calcium carbonate consists of ground calcium carbonate.

[0069] (3-2) Trace components in inorganic powders As described above, the present invention uses an inorganic powder having a trace component content within a predetermined range. By adjusting these components, it is possible to prevent impurities from entering the contents of the container even if the screw threads of the container are damaged.

[0070] (3-2-1) Lead In one embodiment of the present invention, the lead content per gram of the inorganic powder is 20 μg or less. The lower the lead content, the more easily the effects of the present invention are exhibited. The lead content is preferably 10 μg or less, and more preferably 3 μg or less, per gram of the inorganic substance powder. The lower limit of the lead content is not particularly limited, but is preferably 0.0 μg or more per 1 g of the inorganic substance powder.

[0071] (3-2-2) Alkali metals and magnesium In one embodiment of the present invention, the total amount of alkali metal and magnesium is 1.0 mass % or less when the inorganic substance powder is taken as 100 mass %. The lower the total amount of alkali metals and magnesium, the more easily the effects of the present invention are exhibited. When the inorganic substance powder is taken as 100% by mass, the total amount is preferably 0.8% by mass or less, and more preferably 0.7% by mass or less. The lower limit of the total amount of alkali metal and magnesium is not particularly limited, but is preferably 0.0% by mass or more, assuming that the inorganic substance powder is 100% by mass.

[0072] (3-2-3) Other trace elements The contents of the other minor components are not particularly limited, but the higher the purity of the inorganic substance powder, the more easily the effects of the present invention can be achieved.

[0073] For example, if the arsenic content per gram of the inorganic substance powder is preferably 3 μg or less, more preferably 2 μg or less, the safety of the container of the present invention is likely to be increased.

[0074] (3-2-4) Method for adjusting the content of trace elements The method for adjusting the contents of trace components is not particularly limited, but examples thereof include the following. Synthesis or collection of inorganic powders that meet the requirements of the present invention. A blend of an inorganic powder not meeting any of the requirements of the present invention with an inorganic powder that does meet the requirements of the present invention. A blend of an inorganic powder that does not meet only one of the requirements of the present invention (e.g., only the lead content) and an inorganic powder that does not meet only another requirement of the present invention (e.g., only the total amount of alkali metal and magnesium).

[0075] (3-2-5) Measurement method for trace elements The amount of trace elements contained in the inorganic powder can be determined by the method described in the 9th edition of the Official Specification of Food Additives (Ministry of Health, Labor and Welfare, Consumer Affairs Agency) shown in the examples.

[0076] (3-3) Other conditions of inorganic powder The inorganic powder may be in any form so long as it satisfies the above conditions for the minor components.

[0077] The average particle size of the inorganic powder can be appropriately set depending on the moldability to be achieved. However, from the viewpoint of easily achieving stable dispersibility and easily achieving uniform mechanical properties throughout the resin molded product, the average particle size of the inorganic substance powder as measured by the air permeation method in accordance with JIS M-8511 is preferably 0.7 μm or more and 6.0 μm or less, and more preferably 1.0 μm or more and 5.5 μm or less. The average particle size of the inorganic substance powder may be any size as long as the entire inorganic substance powder satisfies the above requirement.

[0078] In order to enhance the dispersibility and reactivity of the inorganic substance powder, the surface of the inorganic substance powder may or may not be previously modified in accordance with a conventional method. Examples of surface modification methods include physical treatment methods (plasma treatment, etc.) and chemical treatment methods (methods using coupling agents or surfactants).

[0079] The shape of the inorganic substance powder is not particularly limited, and may be any of particles (spherical, irregular, etc.), flakes, granules, fibers, and the like.

[0080] (3-4) Amount of inorganic powder In one embodiment of the present invention, the content of the inorganic substance powder is not particularly limited as long as the content of the inorganic substance powder relative to the entire container is more than 50.0 mass % and 80.0 mass % or less.

[0081] The lower limit of the content of the inorganic substance powder is more than 50.0 mass%, preferably 52.0 mass% or more, more preferably 54.0 mass% or more, and even more preferably 56.0 mass% or more, based on the entire container, from the viewpoint of blending a sufficient amount of inorganic substance powder and solving the problems specific to the present invention.

[0082] From the viewpoint of moldability, the upper limit of the content of the inorganic powder is 80.0 mass % or less, preferably 78.0 mass % or less, more preferably 76.0 mass % or less, and further preferably 74.0 mass % or less, based on the entire container.

[0083] The lower limit of the content of the inorganic substance powder is more than 50.0 mass%, preferably 52.0 mass% or more, more preferably 54.0 mass% or more, and even more preferably 56.0 mass% or more, of the screw-on portion of the container, from the viewpoint of blending a sufficient amount of inorganic substance powder and solving the problems specific to the present invention. It is preferable that either the container body or the screw-on portion of the lid of the container satisfies the above requirements, and it is more preferable that both of them satisfy the requirements.

[0084] From the viewpoint of moldability, the upper limit of the content of the inorganic powder is 80.0 mass % or less, preferably 78.0 mass % or less, more preferably 76.0 mass % or less, and even more preferably 74.0 mass % or less, relative to the threaded portion of the container. It is preferable that either the container body or the screw-on portion of the lid of the container satisfies the above requirements, and it is more preferable that both of them satisfy the requirements.

[0085] From the viewpoint of easily solving the problems specific to the present invention, the content of calcium carbonate in the inorganic substance powder is preferably 70.0 mass % or more, more preferably 80.0 mass % or more, and most preferably 100.0 mass % based on the total inorganic substance powder.

[0086] Whether or not the inorganic powder contains calcium carbonate and its content can be determined by firing the resin molded product and analyzing its ash content.

[0087] (4) Other ingredients The container may contain, or may not contain, other components than the inorganic substance powder and the thermoplastic resin, as long as the effects of the present invention are not impaired.

[0088] As the other components, any components that can be usually blended in resin molded products can be used. Such components include colorants, lubricants, dispersants, antistatic agents, antioxidants, heat stabilizers, and ultraviolet absorbing agents. The types and amounts of these components can be appropriately determined depending on the effects to be obtained.

[0089] In a preferred embodiment of the present invention, the container includes those made only of a thermoplastic resin and an inorganic powder.

[0090] (5) Ratio of thermoplastic resin to inorganic powder In the container, the mass ratio of the thermoplastic resin to the inorganic substance powder (thermoplastic resin:inorganic substance powder) is preferably less than 50:more than 50 to 20:80, more preferably 45:55 to 20:80, and even more preferably 40:60 to 25:75.

[0091] (6) Manufacturing method of container The method for producing the container is not particularly limited, and any method known as a method for producing a resin container or the like can be used.

[0092] For example, the components of the container may be pelletized (resin composition) and then molded into a container, or the components of the container may be melt-kneaded and then molded into a container as is.

[0093] Methods for forming the container include injection molding, compression molding, and the like.

[0094] If necessary, an ink receiving layer may be provided on the surface of the container. In the present invention, the "ink receiving layer" includes any configuration employed in the field of printing paper, and includes, for example, a coating layer for fixing ink applied in printing without bleeding. The printing method is not particularly limited, and examples thereof include inkjet printing. The type of coating layer is not particularly limited, and includes a swelling type, a matte type, and the like. The ink-receiving layer can be provided by applying a coating liquid for the ink-receiving layer onto the surface of the single layer portion using a coating device (gravure coater, bar coater, etc.) and drying the coating liquid.

[0095] (7) Use of container The container can be used to hold any object.

[0096] The container may be, for example, a pharmaceutical container, a cosmetic container, and the like.

[0097] The form of the product to be placed in the container is not particularly limited, and may be liquid, solid, gel, cream, or the like. EXAMPLES

[0098] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0099] <Production and evaluation of containers> Approximately cylindrical wide-mouth containers (jars) were produced using the following method, and the presence and extent of lead contamination was evaluated when a local load was applied to the screw threads.

[0100] (1) Preparation of materials The container materials were prepared as follows:

[0101] (1-1) Inorganic substance powder As the inorganic powder, calcium carbonate particles (ground calcium carbonate particles) were used. The calcium carbonate particles had an average particle size of 2.0 μm as measured by an air permeability method in accordance with JIS M-8511.

[0102] First, three types of calcium carbonate with different trace element contents (calcium carbonate purity) collected from different mines were blended in various ratios to prepare inorganic powders 1 to 3 (Table 1). The trace element content in calcium carbonate particles was measured in accordance with the section on "Calcium Carbonate" (pages 748-749) of the 9th edition of the Japanese Standards for Food Additives (Ministry of Health, Labor and Welfare, Consumer Affairs Agency). This standard specifies the method for measuring trace elements (lead, alkali metals and magnesium, hydrochloric acid insolubles, free alkali, etc.) contained in calcium carbonate.

[0103] In Table 1, the contents of each trace component have the following meanings. Lead: Lead content per gram of inorganic powder (unit: μg) Alkali metals: The total amount of alkali metals and magnesium when the inorganic powder is taken as 100% by mass (unit: mass%) Arsenic: Arsenic content per gram of inorganic powder (unit: μg)

[0104] [Table 1]

[0105] (1-2)Thermoplastic resin The following thermoplastic resins were used: Polypropylene resin (PP): Polypropylene block copolymer (melting point 160°C) Polyethylene resin (PE): Blend of HDPE and LLDPE (HDPE:LLDPE (mass ratio) = 70:30) The MFR (190°C, 2.16 kg) of the above HDPE according to JIS K 6922-1 (ISO1133) is 7.5 g / 10 min. The MFR (190°C, 2.16 kg) of the above LLDPE according to JIS K 6922-1 (ISO1133) is 0.8 g / 10 min.

[0106] (2) Preparation of the container Thermoplastic resins and inorganic powders were mixed in the ratios shown in Tables 2 to 5 to obtain pellets. Next, the obtained pellets were used to prepare a container (container body and lid) by injection molding. A transparent gel was poured into the resulting container up to about 1 / 3 of the height of the container body.

[0107] The roughly cylindrical wide-mouth container made in this example is composed of a container body having an opening and a lid that closes the opening. The container body and the lid are each formed with a screw thread (screwed portion) and are designed to be screwed together. The dimensions of each part of the container are as follows:

[0108] (2-1) Container body dimensions Body diameter: 90mm Height: 85mm Thread diameter: 63mm Thread height: 1.5mm Neck length (where the thread is located): 20mm

[0109] (2-2) Lid dimensions Lid outer diameter: 70mm Height: 25mm Thread height: 1.5mm

[0110] (3) Strength rating -1 For each container having the composition shown in Tables 2 and 3, a drop impact test was performed on the entire container in accordance with JIS Z 0202, and the container was evaluated according to the following criteria. The results are shown in the "Drop test" section of Tables 2 and 3.

[0111] [Evaluation Criteria] None: No damage to the container was observed. Minor: Minor damage to the container (cracks, etc.) was observed. Many: Clear damage to the container (cracks, chips, etc.) was observed.

[0112] As shown in Tables 2 and 3, the strength (impact resistance, etc.) of the entire container was higher as the content of inorganic substance powder increased. In this example, the results are shown using "Inorganic Powder 1." However, the same trends were observed when "Inorganic Powder 2" or "Inorganic Powder 3" was used instead of "Inorganic Powder 1."

[0113] (4) Strength rating -2 First, the lids of each container having the compositions shown in Tables 2 and 3 were screwed onto the container body up to about halfway up the neck height, leaving the lids half-closed (i.e., not completely closed). In this state, a load was applied from directly above the lid toward the container body. This test was performed with reference to tensile tests (JIS K 7113, etc.).

[0114] When the loaded lid reached the bottom of the neck of the container, the lid was removed and the threads were visually inspected for damage and rated according to the following criteria. The results are shown in the "Damage" section of Tables 2 and 3.

[0115] [Evaluation Criteria] None: No damage to the threads was observed. Minor: Minor damage to the screw threads (cracks, etc.) was observed. Most: Clear damage to the screw threads (cracks, chips, etc.) was observed.

[0116] As shown in Tables 2 and 3, the higher the content of inorganic substance powder (particularly when it exceeded 50.0 mass %), the more clearly damage to the screw threads due to the load on the lid was observed. As shown in "Strength Evaluation-1," the strength (impact resistance, etc.) of the container as a whole was higher the higher the inorganic powder content, but it was a very surprising finding that resistance to such localized loads was poor.

[0117] (5) Evaluation of trace element contamination As in the above "Strength Evaluation-2," the lid of each container was screwed onto about half of the neck height of the container body, and with the lid half-closed, a load was applied from directly above the lid toward the container body until it reached the bottom of the neck height of the container body. Next, the lid of the container was removed, and all the gel in the container was collected. The total amount of trace elements (lead, etc.) in the gel was confirmed in accordance with the section on "Calcium Carbonate" (pages 748-749) of the 9th Edition of the Official Specification for Food Additives (Ministry of Health, Labor and Welfare, Consumer Affairs Agency), and evaluated according to the following criteria. The results are shown in the section on "Contamination of Trace Elements" in Tables 4 and 5.

[0118] [Evaluation Criteria] None: No trace elements were detected. Low: Lead content was less than 0.01 μg per gram of gel. Most: The lead content was over 0.01 μg per gram of gel.

[0119] [Table 2]

[0120] [Table 3]

[0121] [Table 4]

[0122] [Table 5]

[0123] First, as shown in the "Reference Example", it was confirmed that the drop impact resistance tends to increase as the content of inorganic substance powder increases. However, the higher the content of inorganic powder, the lower the resistance to localized load. It has been known in the past that blending inorganic powders improves the mechanical properties of resin products, but the finding that they may be inferior in terms of resistance to such localized loads is quite unexpected.

[0124] From the above results, the inventors confirmed that containers with a high content of inorganic substance powder, particularly those with a content of more than 50.0% by mass and not more than 80.0% by mass, are prone to thread damage, despite the mechanical properties of the container as a whole being good.

[0125] As shown in the "Examples", it has been determined that even if damage to the threads occurs in a container that is highly filled with inorganic powder, the inclusion of trace components can be suppressed by satisfying the requirements of the present invention.

[0126] On the other hand, in the "Comparative Example" which does not satisfy the requirements of the present invention, a large amount of impurities was mixed into the contents of the container. It should also be noted that in containers with a low content of inorganic substance powder (e.g., Comparative Example 3-2), even though inorganic substance powder with a high content of trace components is used, the content of inorganic substance powder is low, so that damage to the threads does not occur in the first place and the problem of the present invention does not exist.

[0127] In this example, heavy calcium carbonate was used as the inorganic powder, but the same tendency as above was observed with other inorganic powders (light calcium carbonate, talc, etc.).

Claims

1. A container comprising: The container comprises a container body having an opening and a lid for closing the opening, the opening includes a first threaded portion; the lid includes a second screw portion that is screwed into the first screw portion, the first screw-type portion and the second screw-type portion contain an inorganic powder and a thermoplastic resin; The content of the inorganic substance powder is more than 50.0 mass% and 80.0 mass% or less with respect to the entire container body having the same composition, The content of the inorganic powder is more than 50.0 mass% and 80.0 mass% or less with respect to the entire lid having the same composition, A container in which the inorganic powder satisfies all of the following requirements: (Requirement 1) The lead content per gram of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is taken as 100% by mass, the total amount of alkali metal and magnesium is 1.0% by mass or less.

2. A container comprising: The container comprises a container body having an opening and a lid for closing the opening, the opening includes a first threaded portion; the lid includes a second screw portion that is screwed into the first screw portion, the first screw-type portion and the second screw-type portion contain an inorganic powder and a thermoplastic resin; The content of the inorganic powder is more than 50.0% by mass and not more than 80.0% by mass with respect to the entire container, The content of the inorganic powder in the screw portion of the container body is more than 50.0% by mass, The content of the inorganic powder in the screw-on portion of the lid is more than 50.0% by mass, A container in which the inorganic powder satisfies all of the following requirements: (Requirement 1) The lead content per gram of the inorganic substance powder is 20 μg or less. (Requirement 2) When the inorganic substance powder is taken as 100% by mass, the total amount of alkali metal and magnesium is 1.0% by mass or less.

3. 3. The container of claim 1 or 2, wherein the powdered inorganic material comprises calcium carbonate.

4. 4. The container of claim 3, wherein the calcium carbonate comprises ground calcium carbonate.

5. 3. The container according to claim 1 or 2, wherein the inorganic powder further satisfies the following requirements: (Requirement 3) The arsenic content per gram of the inorganic substance powder is 3 μg or less.

6. 5. The container according to claim 4, wherein the ground calcium carbonate contains ground calcium carbonate having an average particle size of 0.7 μm or more and 6.0 μm or less, as measured by an air permeability method in accordance with JIS M-8511.

7. The container according to claim 1 or 2, wherein the thermoplastic resin comprises a polypropylene-based resin and / or a polyethylene-based resin.

8. The container according to claim 7, wherein the polyethylene resin comprises high density polyethylene and / or linear low density polyethylene.

9. The container according to claim 7 , wherein the polypropylene-based resin comprises a polypropylene homopolymer and / or a polypropylene block polymer.

10. The container according to claim 1 or 2, wherein the container is obtained by injection molding or compression molding.

11. The container according to claim 1 or 2, which is a pharmaceutical container.

12. The container according to claim 1 or 2, which is a cosmetic container.

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