Foamable resin particles, method for producing same, foamed particles, and foamed molded article

Abstract

Provided are foamable resin particles, a method for producing the same, foamed particles, and a foamed molded article. [Problem] To provide foamable resin particles capable of providing a foam molded body having excellent antibacterial properties. [Solution] A foamable resin particle comprising a base resin and a foaming agent, the base resin comprising a styrene-based resin, the foamable resin particles further contain, on the surface thereof, (A) an amine compound and (B) one or more substances selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol having a specific molecular weight, and polybutylene glycol having a specific molecular weight.

Description

Technical Field

[0001] The present invention relates to expandable resin particles, a method for producing the same, expandable particles and an expandable molded article. Background Art

[0002] As expandable resin particles, expandable polystyrene resin particles are widely known. Expandable polystyrene resin particles are generally widely used because they can easily obtain a molded body by in-mold foam molding and are inexpensive.

[0003] For example, Patent Document 1 proposes low-charge expandable styrene resin particles, expandable particles, and a foamed molded article containing N-hydroxyethyl-N-2-hydroxyalkylamine.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Publication No. 2017-114987 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, from the viewpoint of antimicrobial properties, there is room for improvement in the foamed molded article obtained from the foamable resin particles obtained by the above-mentioned conventional techniques.

[0009] One embodiment of the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a novel expandable resin particle capable of providing an expandable molded product having excellent antibacterial properties.

[0010] Solutions for solving problems

[0011] The present inventors have conducted intensive studies to solve the above-mentioned problems and have completed the present invention as a result.

[0012] The expandable resin particles according to one embodiment of the present invention include a base resin and a foaming agent, wherein the base resin includes a styrene-based resin, and the surface of the expandable resin particles includes (A) an amine compound and (B) one or more selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol, and polybutylene glycol, wherein the number average molecular weight of the polypropylene glycol is 800 or more, and the number average molecular weight of the polybutylene glycol is 300 or more.

[0013] A method for producing expandable resin particles according to one embodiment of the present invention is a method for producing expandable resin particles comprising a base resin and a foaming agent, the method comprising a coating step of coating (A) an amine compound and (B) one or more selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol and polybutylene glycol on the surface of a main body of the expandable resin particles, wherein the base resin comprises a styrene-based resin, the number average molecular weight of the polypropylene glycol is 800 or more, and the number average molecular weight of the polybutylene glycol is 300 or more.

[0014] Effects of the Invention

[0015] According to one embodiment of the present invention, there is provided an effect of being able to provide novel expandable resin particles capable of providing an expandable molded article having excellent antibacterial properties. DETAILED DESCRIPTION

[0016] An embodiment of the present invention is described below, but the present invention is not limited thereto. The present invention is not limited to the various structures described below, and various changes can be made within the scope indicated in the claims. In addition, embodiments or embodiments obtained by combining the technical means respectively disclosed in different embodiments or examples are also included in the protection scope of the present invention. Furthermore, by combining the technical means respectively disclosed in each embodiment, new technical features can be formed. It should be noted that all the academic literature and patent documents recorded in this specification are cited as references in this specification. In addition, in this specification, unless otherwise specified, "A~B" indicating a numerical range means "above A (including A and greater than A) and below B (including B and less than B)".

[0017] In the present specification, "X unit" contained in a polymer, copolymer or resin means "a structural unit derived from a monomer of X". For example, "styrene unit" means "a structural unit derived from a styrene monomer".

[0018] Unless otherwise specified in this manual, 1 Unit, X 2 Unit, ... and X n A copolymer having a unit (n is an integer greater than 2) as a structural unit is also referred to as "X 1 / X 2 / … / X n Copolymer". As X 1 / X 2 / … / X n The copolymer is not particularly limited in the polymerization method unless otherwise specified, and may be a random copolymer, an alternating copolymer, a block copolymer, or a graft copolymer.

[0019] [1. Technical concept of one embodiment of the present invention]

[0020] Antimicrobial properties may be required for foam molded products. Therefore, the present inventors have conducted intensive studies with the purpose of providing novel foamable resin particles capable of providing (a) foam molded products having excellent antimicrobial properties.

[0021] In the past, as an external additive for foamable resin particles, N-hydroxyethyl-N-2-hydroxyalkylamine is known, as described in Patent Document 1. Patent Document 1 discloses a technique for containing N-hydroxyethyl-N-2-hydroxyalkylamine in foamable resin particles for the purpose of exhibiting antistatic properties. It should be noted that Patent Document 1 does not describe any antibacterial properties.

[0022] The present inventors have conducted studies and have obtained new knowledge that when the surface of expandable resin particles is coated with N-hydroxyethyl-N-2-hydroxyalkylamine disclosed in Patent Document 1, a foamed molded article obtained from the expandable resin particles cannot exhibit antimicrobial properties.

[0023] As a result of further in-depth research, the present inventors have obtained the following new insight: by applying (B) component (one or more selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol having a number average molecular weight greater than a specific value, and polybutylene glycol having a number average molecular weight greater than a specific value) together with (A) amine compound to the surface of foamable resin particles, surprisingly, the foamed molded product obtained from the obtained foamable resin particles has excellent antibacterial properties.

[0024] [2. Expandable resin particles]

[0025] The expandable resin particles according to one embodiment of the present invention contain a base resin and a foaming agent, wherein the base resin contains a styrene-based resin, and the surfaces of the expandable resin particles contain (A) an amine compound and (B) one or more selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol, and polybutylene glycol, wherein the number average molecular weight of the polypropylene glycol is 800 or more, and the number average molecular weight of the polybutylene glycol is 300 or more.

[0026] The foamable resin particles of one embodiment of the present invention have the above-mentioned structure, and therefore have the advantage of being able to provide a foamed molded product with excellent antibacterial properties. Specifically, the foamable resin particles of one embodiment of the present invention have the above-mentioned structure, so the foamable resin particles themselves have excellent antibacterial properties, and therefore foamable particles with excellent antibacterial properties can be provided. The foamable particles with excellent antibacterial properties obtained from the foamable resin particles of one embodiment of the present invention can provide a foamed molded product with excellent antibacterial properties. The evaluation method of antibacterial properties is described in detail in the following examples.

[0027] The foamable resin particles of one embodiment of the present invention have the above-mentioned structure, and therefore also have the advantage of being able to provide a foamed molded product with excellent antiviral properties. Specifically, the foamable resin particles of one embodiment of the present invention have the above-mentioned structure, so the foamable resin particles themselves have excellent antiviral properties, and thus foamed particles with excellent antiviral properties can be provided. The foamed particles with excellent antiviral properties obtained from the foamable resin particles of one embodiment of the present invention can provide a foamed molded product with excellent antiviral properties.

[0028] In this specification, particles obtained by foaming expandable resin particles are sometimes referred to as "expandable particles", and a molded product obtained by molding the expandable particles is sometimes referred to as "expandable molded product". In this specification, "expandable resin particles, expandable particles, and expandable molded products" are sometimes referred to as "expandable resin particles, etc.". In this specification, "expandable resin particles according to one embodiment of the present invention" are sometimes referred to as "the present expandable resin particles", "expandable particles according to one embodiment of the present invention" are sometimes referred to as "the present expandable particles", and "expandable molded products according to one embodiment of the present invention" are sometimes referred to as "the present expandable molded products". In this specification, "(A) amine compound" is sometimes referred to as "(A) component", and "(B) one or more selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol, and polybutylene glycol" is sometimes referred to as "(B) component".

[0029] In the following description of this specification, (i) resin particles containing a base resin and a foaming agent but not containing the component (A), the component (B) and / or other external additives described later on the surface thereof may be referred to as "foamable resin particle bodies", and (ii) resin particles containing a base resin and a foaming agent and further containing the component (A) and the component (B) and optionally containing other external additives on the surface thereof may be referred to as "foamable resin particles". In this specification, "foamable resin particle bodies according to one embodiment of the present invention" may be referred to as "the present foamable resin particle bodies".

[0030] In the present specification, the surface of the foamable resin particles containing (A) amine compound refers to any of the following states: (i) a state in which the entire amount of the (A) amine compound contained in the foamable resin particles forms a layer on the surface of the foamable resin particle body, (ii) a state in which the entire amount of the (A) amine compound contained in the foamable resin particles is impregnated in the surface layer of the foamable resin particles, or (iii) a state in which a part of the (A) amine compound contained in the foamable resin particles forms a layer on the surface of the foamable resin particle body and the remaining part of the (A) amine compound is impregnated in the surface layer of the foamable resin particles.

[0031] As a mode of containing (A) amine compound on the surface of foamable resin particles, among the above-mentioned states (i) to (iii), from the viewpoint of more easily exhibiting antibacterial and antiviral properties, a state in which the total amount of (A) amine compound contained in (i) foamable resin particles forms a layer on the surface of the foamable resin particle body is more preferred.

[0032] In the present specification, the presence of component (B) on the surface of the foamable resin particles refers to any of the following states: (i) a state in which the entire amount of component (B) contained in the foamable resin particles forms a layer on the surface of the foamable resin particle body, (ii) a state in which the entire amount of component (B) contained in the foamable resin particles is impregnated in the surface portion of the foamable resin particles, or (iii) a state in which a portion of component (B) contained in the foamable resin particles forms a layer on the surface of the foamable resin particle body and the remaining portion of the component (B) is impregnated in the surface portion of the foamable resin particles.

[0033] As a method of containing the component (B) on the surface of the foamable resin particles, among the above-mentioned states (i) to (iii), from the viewpoint of more easily exhibiting antibacterial and antiviral properties, it is more preferable that the state (i) is a state in which the entire amount of the component (B) contained in the foamable resin particles forms a layer on the surface of the foamable resin particle body.

[0034] (2-1. Expandable resin particle body)

[0035] The expandable resin particle body contains a base resin and a foaming agent. The expandable resin particle body may contain other additives described below as necessary.

[0036] It can be said that the expandable resin beads according to one embodiment of the present invention include an expandable resin particle body and contain the (A) amine compound and the (B) component on the surface.

[0037] (2-2. Base material resin)

[0038] In one embodiment of the present invention, the aforementioned base resin comprises a styrene resin. In this specification, "styrene resin" refers to a resin in which the number of styrene units is 50% or more when the number of all structural units contained in the resin is set to 100%. In one embodiment of the present invention, the aforementioned base resin may (a) consist only of a styrene resin, or (b) contain a resin other than a styrene resin within a range that does not impair the effect of one embodiment of the present invention.

[0039] The aforementioned styrene resin may be a homopolymer of styrene consisting only of styrene units. The aforementioned styrene resin may also be a copolymer consisting of styrene units and structural units derived from monomers other than styrene. In the copolymer, the structural units derived from monomers other than styrene may be one kind, or may be two or more kinds.

[0040] Examples of the monomers other than styrene include (a) monofunctional monomers such as styrene derivatives, acrylates, methacrylates, acrylonitrile, dimethyl fumarate and ethyl fumarate, and (b) bifunctional monomers such as divinylbenzene and alkylene glycol dimethacrylate.

[0041] Examples of the styrene derivatives include α-methylstyrene, p-methylstyrene, tert-butylstyrene, and chlorostyrene.

[0042] Examples of the acrylic acid ester include methyl acrylate, ethyl acrylate, butyl acrylate, and hexadecyl acrylate.

[0043] Examples of the methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, and hexadecyl methacrylate.

[0044] (2-3. Foaming agent)

[0045] The foaming agent contained in the expandable resin particles is not particularly limited.

[0046] Specific examples of the aforementioned foaming agent include: (a) aliphatic hydrocarbons having 3 to 5 carbon atoms, such as propane, n-butane, isobutane, n-pentane, isopentane and neopentane; and (b) fluorocarbons having an ozone depletion coefficient of zero, such as difluoroethane and tetrafluoroethane; and other volatile foaming agents.

[0047] These foaming agents may be used alone or in combination of two or more.

[0048] The content of the foaming agent in the expandable resin particles is preferably 3 to 10 parts by weight, more preferably 4 to 8 parts by weight, based on 100 parts by weight of the base resin.

[0049] (2-4. Other additives)

[0050] The foamable resin particle body may optionally contain other additives in addition to the base resin and the foaming agent, within the scope of not impairing the effect of one embodiment of the present invention. Examples of the aforementioned other additives include: solvents, plasticizers, bubble regulators, nucleating agents, flame retardants, flame retardant aids, heat ray radiation inhibitors, pigments, dyes, and monomer components.

[0051] The aforementioned other additives can be added to the foamable resin particle body, for example, when the foamable resin particle body is manufactured. There is no particular limitation on the time and / or method of adding these other additives to the foamable resin particle body. When the foamable resin particle body contains other additives, the foamable resin particles may also contain other additives.

[0052] (2-5. Method for producing expandable resin particle body)

[0053] As a method for manufacturing the main body of the foamable resin particles, there can be cited a method in which, after preparing (polymerizing) the aforementioned base resin, the aforementioned foaming agent is impregnated into the obtained aforementioned base resin. Regarding the preparation method (polymerization method) of the aforementioned base resin and the impregnation method of the aforementioned foaming agent, both known manufacturing methods can be applied without particular limitation. However, in the case of adopting a seed suspension polymerization method as the preparation method of the aforementioned base resin, the structural unit in the resin particle main body that becomes the seed (i.e., the structural unit contained in the seed) is also included as the structural unit of the base resin of the foamable resin particle main body (i.e., the structural unit of the base resin of the foamable resin particle).

[0054] (2-6. (A) Amine compound)

[0055] The present expandable resin particles contain an amine compound as the component (A). By coating the component (A) on the surface of the expandable resin particle body, expandable resin particles containing the component (A) on the surface of the expandable resin particles can be obtained.

[0056] The (A) component coated on the foamable resin particle body is substantially entirely attached to the foamable resin particle body and is contained in the foamable resin particle. In this specification, among the additives, the additives contained on the surface of the foamable resin particle, in other words, the additives coated on the surface of the foamable resin particle body are referred to as "external additives". That is, the (A) component functions as an external additive, and the (A) component can also be referred to as an external additive. In addition, the "content" of the (A) component in the foamable resin particles can also be referred to as the "coating amount" of the (A) component on the foamable resin particle body.

[0057] The foamable resin particles have excellent antibacterial properties by containing component (A), and can provide foamable particles and foamed molded products with excellent antibacterial properties. The reason why the antibacterial properties of the foamable resin particles, etc. are expressed by component (A) is still uncertain, but it is speculated as follows: it is believed that component (A) (such as alkylamine compounds and alkenylamine compounds) weakens the intermolecular interactions of substances constituting the cell membrane and cell wall of bacteria, destroying the cell membrane and cell wall. More specifically, component (A) interacts or combines with substances constituting the cell membrane and cell wall of bacteria, thereby hindering the binding (intermolecular binding) of substances constituting the cell membrane and cell wall of bacteria, and as a result, the cell membrane and cell wall of bacteria can be destroyed. It should be noted that the present invention is not limited to this speculation.

[0058] The foamable resin particles sometimes have excellent antiviral properties by including component (A), and sometimes can provide foamable particles and foamed molded products with excellent antiviral properties. The reason why the antiviral properties of the foamable resin particles, etc., are expressed by component (A) is not clear, but it is speculated as follows: it is believed that component (A) (such as alkylamine compounds and alkenylamine compounds) destroys the outer membrane (capsid) of the virus, or denatures the protein that forms the capsid to stop the function of the virus. It should be noted that the present invention is not limited to this speculation.

[0059] As (A) amine compound, there is no particular limitation. From the aspect that the antibacterial property of the foamable resin particles is more excellent, the (A) amine compound contained in the foamable resin particles preferably includes one or more selected from the group consisting of alkylamine compounds and alkenylamine compounds, and more preferably only consists of one or more selected from the group consisting of alkylamine compounds and alkenylamine compounds. From the aspect that the antibacterial property of the foamable resin particles is more excellent, the (A) amine compound contained in the foamable resin particles preferably includes one or more selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine, salts of N-hydroxyethyl-N-2-hydroxyalkylamine, alkylamine compounds without hydroxyl groups, and alkenylamine compounds without hydroxyl groups, and more preferably only consists of one or more selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine, salts of N-hydroxyethyl-N-2-hydroxyalkylamine, alkylamine compounds without hydroxyl groups, and alkenylamine compounds without hydroxyl groups.

[0060] In this specification, a "salt of N-hydroxyethyl-N-2-hydroxyalkylamine" may be referred to as an "N-hydroxyethyl-N-2-hydroxyalkylamine salt". In this specification, an "alkylamine compound having no hydroxyl group" may be referred to as an "alkylamine compound X", and an "alkenylamine compound having no hydroxyl group" may be referred to as an "alkenylamine compound X".

[0061] (N-Hydroxyethyl-N-2-hydroxyalkylamine)

[0062] The aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine is not particularly limited. The aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine is more preferably an N-hydroxyethyl-N-2-hydroxyalkylamine having 10 to 18 carbon atoms in the 2-hydroxyalkyl group, one amino group in the molecule and two hydroxyl groups in the molecule. It should be noted that in the present specification, "amino group" refers to an amino group having a substituent bonded to the N of the amino group. When the number of carbon atoms in the 2-hydroxyalkyl group is 10 or more, the N-hydroxyethyl-N-2-hydroxyalkylamine tends to: (i) not penetrate into the interior of the foamable resin particle body, but to form a layer on the surface of the foamable resin particle body, or (ii) even if it penetrates into the foamable resin particle body, the impregnation area is limited to the surface layer of the foamable resin particle body. Therefore, when the carbon number of the 2-hydroxyalkyl group is 10 or more, the ratio of the N-hydroxyethyl-N-2-hydroxyalkylamine forming the layer on the surface of the expandable resin particle body increases, which has the advantage of being able to express excellent antibacterial and antiviral properties.

[0063] In addition, when the number of carbon atoms of the 2-hydroxyalkyl group is 18 or less, the melting point of the N-hydroxyethyl-N-2-hydroxyalkylamine does not become too high, so when the foamed particles are heated during molding, the N-hydroxyethyl-N-2-hydroxyalkylamine on the surface of the foamed particles is easily melted. Therefore, the possibility of deteriorating the welding of the foamed molded body due to the melting residue of the amine can be reduced, so a foamed molded body with good welding properties can be obtained. The aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine can be a mixture of at least two N-hydroxyethyl-N-2-hydroxyalkylamines in which the number of carbon atoms of the 2-hydroxyalkyl group is selected from 10 to 18. From the viewpoint of good welding properties and processability brought about by reducing the possibility of deteriorating the welding properties of the foamed molded body, as well as excellent antibacterial and antiviral properties, the number of carbon atoms of the 2-hydroxyalkyl group of the aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine is more preferably 12 to 16, and further preferably 14. Alternatively, from the viewpoint of excellent antibacterial and antiviral properties of the foamed molded article after light irradiation, the carbon number of the 2-hydroxyalkyl group of the N-hydroxyethyl-N-2-hydroxyalkylamine may preferably be 10 to 16, more preferably 10 to 13, and even more preferably 10 to 12.

[0064] (Salt of N-hydroxyethyl-N-2-hydroxyalkylamine)

[0065] The N-hydroxyethyl-N-2-hydroxyalkylamine salt is not particularly limited as long as it is a salt of N-hydroxyethyl-N-2-hydroxyalkylamine. The N-hydroxyethyl-N-2-hydroxyalkylamine salt is more preferably a salt of N-hydroxyethyl-N-2-hydroxyalkylamine in which the carbon number of the 2-hydroxyalkyl group is 8 to 14, one amino group is present in the molecule, and two hydroxyl groups are present in the molecule. The N-hydroxyethyl-N-2-hydroxyalkylamine salt may be a mixture of at least two N-hydroxyethyl-N-2-hydroxyalkylamine salts in which the carbon number of the 2-hydroxyalkyl group is selected from 8 to 14. When the carbon number of the 2-hydroxyalkyl group is 8 or more, the hydrophobicity of the N-hydroxyethyl-N-2-hydroxyalkylamine salt increases, and thus the solubility in water decreases. Therefore, the N-hydroxyethyl-N-2-hydroxyalkylamine salt in which the carbon number of the 2-hydroxyalkyl group is 8 or more is not easily washed away by steam or the like during foaming and molding, and thus the salt is likely to remain in the foamed molded body. Thus, the antibacterial effect of the foamed particles or the foamed molded body becomes good (easy to show). When the carbon number of the 2-hydroxyalkyl group is 14 or less, it does not precipitate when the N-hydroxyethyl-N-2-hydroxyalkylamine salt is made into an aqueous solution. Therefore, the N-hydroxyethyl-N-2-hydroxyalkylamine salt with a carbon number of 14 or less of the 2-hydroxyalkyl group can be evenly coated on the surface of the foamable resin particle body, etc. As a result, the deviation of the antibacterial and antiviral properties of the foamable resin particles and the foamed particles is reduced. The lower limit of the carbon number of the 2-hydroxyalkyl group of the aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine salt is more preferably 9 or more, and more preferably 10 or more. The upper limit of the carbon number of the 2-hydroxyalkyl group of the aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine salt is more preferably 13 or less, and more preferably 12 or less.

[0066] The N-hydroxyethyl-N-2-hydroxyalkylamine salt more preferably contains an N-hydroxyethyl-N-2-hydroxyalkylamine salt having a 2-hydroxyalkyl group with 10 carbon atoms and an N-hydroxyethyl-N-2-hydroxyalkylamine salt having a 2-hydroxyalkyl group with 12 carbon atoms, and a mixture thereof is particularly preferred. The case where the N-hydroxyethyl-N-2-hydroxyalkylamine salt contains an N-hydroxyethyl-N-2-hydroxyalkylamine salt having a 2-hydroxyalkyl group with 10 carbon atoms and an N-hydroxyethyl-N-2-hydroxyalkylamine salt having a 2-hydroxyalkyl group with 12 carbon atoms, or a mixture thereof, will be described. At this time, the ratio of the content of the N-hydroxyethyl-N-2-hydroxyalkylamine salt having 10 carbon atoms in the 2-hydroxyalkyl group to the content of the N-hydroxyethyl-N-2-hydroxyalkylamine salt having 12 carbon atoms (content of the N-hydroxyethyl-N-2-hydroxyalkylamine salt having 10 carbon atoms:content of the N-hydroxyethyl-N-2-hydroxyalkylamine salt having 12 carbon atoms) in the N-hydroxyethyl-N-2-hydroxyalkylamine salt is not particularly limited, but is preferably 90:10 to 10:90, more preferably 70:30 to 30:70, further preferably 60:40 to 40:60, further more preferably 55:45 to 45:55, particularly preferably 52:48 to 48:52, and most preferably 1:1 (50:50).

[0067] The N-hydroxyethyl-N-2-hydroxyalkylamine salt may be a salt with any acid as long as it is a salt of N-hydroxyethyl-N-2-hydroxyalkylamine, and examples thereof include salts with hydrochloric acid, sulfuric acid, nitric acid, etc. The N-hydroxyethyl-N-2-hydroxyalkylamine salt may be used alone or in combination of two or more.

[0068] (Alkylamine compound having no hydroxyl group and alkenylamine compound having no hydroxyl group)

[0069] There is no particular limitation on the alkylamine compound X. In order to obtain expandable resin particles having sufficient antimicrobial properties, the alkylamine compound X preferably contains at least one selected from the group consisting of primary alkylamines, secondary alkylamines, tertiary alkylamines and polyoxyethylene alkylamines, and more preferably contains at least one selected from the group consisting of laurylamine, hexadecylamine, stearylamine, dimethyl laurylamine and polyoxyethylene laurylamine.

[0070] The alkylamine compound X preferably contains 50% by weight or more of one or more selected from the group consisting of primary alkylamines, secondary alkylamines, tertiary alkylamines and polyoxyethylene alkylamines in 100% by weight of the alkylamine compound X, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 90% by weight or more, further preferably 95% by weight or more, further preferably 95% to 100% by weight, and particularly preferably 100% by weight. In other words, the alkylamine compound X is particularly preferably composed of only one or more selected from the group consisting of primary alkylamines, secondary alkylamines, tertiary alkylamines and polyoxyethylene alkylamines. When the amount of one or more selected from the group consisting of primary alkylamines, secondary alkylamines, tertiary alkylamines and polyoxyethylene alkylamines in the alkylamine compound X is within the above range, there is an advantage that foamable resin particles having better antibacterial properties can be obtained.

[0071] There are no particular limitations on the alkenylamine compound X. In order to obtain expandable resin particles having sufficient antimicrobial properties, the alkenylamine compound X preferably contains at least one selected from the group consisting of primary alkenylamines, secondary alkenylamines, tertiary alkenylamines, and polyoxyethylene alkenylamines, and more preferably contains oleylamine.

[0072] The alkenylamine compound X preferably contains 50% by weight or more of one or more selected from the group consisting of primary alkenylamine, secondary alkenylamine, tertiary alkenylamine and polyoxyethylene alkenylamine in 100% by weight of the alkenylamine compound X, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 90% by weight or more, further preferably 95% by weight or more, further preferably 95% to 100% by weight, and particularly preferably 100% by weight. In other words, the alkenylamine compound X is particularly preferably composed of only one or more selected from the group consisting of primary alkenylamine, secondary alkenylamine, tertiary alkenylamine and polyoxyethylene alkenylamine. In the alkenylamine compound X, when the amount of one or more selected from the group consisting of primary alkenylamine, secondary alkenylamine, tertiary alkenylamine and polyoxyethylene alkenylamine is within the above range, there is an advantage that foamable resin particles with better antibacterial properties can be obtained.

[0073] The alkylamine compound X is not particularly limited, but the alkyl group preferably has 12 or more carbon atoms. When the alkyl group of the alkylamine compound X has 12 or more carbon atoms, the alkylamine compound X tends to (i) not penetrate into the interior of the foamable resin particle body, but form a layer on the surface of the foamable resin particle body, or (ii) even if penetrated into the foamable resin particle body, the impregnation area is limited to the surface layer of the foamable resin particle body. Therefore, when the alkyl group of the alkylamine compound X has 12 or more carbon atoms, the proportion of the alkylamine compound X forming a layer on the surface of the foamable resin particle body increases, which has the advantage of being able to exhibit excellent antibacterial and antiviral properties.

[0074] The alkylamine compound X is not particularly limited, but the number of carbon atoms in the alkyl group is preferably 18 or less. When the number of carbon atoms in the alkyl group of the alkylamine compound X is 18 or less, the melting point of the alkylamine compound X does not become too high, so when the foamed beads are heated during molding, the alkylamine compound X on the surface of the foamed beads is easily melted. Therefore, the possibility of deterioration of the welding of the foamed molded article due to the melting residue of the alkylamine compound X can be reduced, so that a foamed molded article with good welding properties can be obtained.

[0075] The alkylamine compound X may be a mixture of at least two alkylamine compounds X having an alkyl group with carbon atoms selected from 12 to 18. The alkyl group of the alkylamine compound X preferably has carbon atoms of 14 to 18, and further preferably has carbon atoms of 16 to 18. According to this configuration, there are the following advantages: (a) foamable resin particles having sufficient antibacterial and antiviral properties can be obtained, (b) foamable resin particles and foamed particles having good fluidity can be obtained, and (c) a foamed molded article having good weldability (i.e., a high weld rate) can be obtained.

[0076] The alkylamine compound X preferably contains 50% by weight or more of an alkylamine compound X having an alkyl group with 12 or more carbon atoms, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 90% by weight or more, further preferably 95% by weight or more, further preferably 95% to 100% by weight, and particularly preferably 100% by weight, in 100% by weight of the alkylamine compound X. In other words, the alkylamine compound X is particularly preferably composed of only the alkylamine compound X having an alkyl group with 12 or more carbon atoms. When the amount of the alkylamine compound X having an alkyl group with 12 or more carbon atoms in the alkylamine compound X is within the above range, there are the following advantages: (a) a foamable resin particle having sufficient antibacterial and antiviral properties can be obtained, (b) a foamable resin particle and a foamed particle having good fluidity can be obtained, and (c) a foamed molded article having good weldability (i.e., a high weld rate) can be obtained.

[0077] The alkenylamine compound X is not particularly limited, but the alkenyl group preferably has 12 or more carbon atoms. When the alkenyl group of the alkenylamine compound X has 12 or more carbon atoms, the alkenylamine compound X tends to (i) not penetrate into the interior of the foamable resin particle body, but to form a layer on the surface of the foamable resin particle body, or (ii) even if it penetrates into the foamable resin particle body, the impregnation area is limited to the surface layer of the foamable resin particle body. Therefore, when the alkenyl group of the alkenylamine compound X has 12 or more carbon atoms, the proportion of the alkenylamine compound X forming a layer on the surface of the foamable resin particle body increases, which has the advantage of being able to exhibit excellent antibacterial and antiviral properties.

[0078] The alkenylamine compound X is not particularly limited, but the number of carbon atoms in the alkenyl group is preferably 18 or less. When the number of carbon atoms in the alkenylamine compound X is 18 or less, the melting point of the alkenylamine compound X does not become too high, so when the foamed particles are heated during molding, the alkenylamine compound X on the surface of the foamed particles is easily melted. Therefore, the possibility of deteriorating the welding of the foamed molded article due to the melting residue of the alkenylamine compound X can be reduced, so a foamed molded article with good welding properties can be obtained.

[0079] The alkenylamine compound X may be a mixture of at least two alkenylamine compounds X having alkenyl carbon atoms selected from 12 to 18. The alkenylamine compound X more preferably has alkenyl carbon atoms of 14 to 18, and further preferably 16 to 18. This configuration has the following advantages: (a) foamable resin particles having sufficient antibacterial and antiviral properties can be obtained, (b) foamable resin particles and foamed particles having good fluidity can be obtained, and (c) a foamed molded article having good weldability (i.e., a high weld rate) can be obtained.

[0080] The alkenylamine compound X preferably contains 50% by weight or more of alkenylamine compounds X having 12 or more carbon atoms in the alkenyl group in 100% by weight of the alkenylamine compound X, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 90% by weight or more, further preferably 95% by weight or more, further preferably 95% to 100% by weight, and particularly preferably 100% by weight. In other words, the alkenylamine compound X is particularly preferably composed of only alkenylamine compounds X having 12 or more carbon atoms in the alkenyl group. When the amount of the alkenylamine compound X having 12 or more carbon atoms in the alkenylamine compound X is within the above range, the following advantages are achieved: (a) foamable resin particles having sufficient antibacterial and antiviral properties can be obtained, (b) foamable resin particles and foamed particles having good fluidity can be obtained, and (c) a foamed molded article having good weldability (i.e., a high weld rate) can be obtained.

[0081] Since the expandable resin particles and the like have particularly excellent antibacterial and antiviral properties, in the expandable resin particles, as the (A) amine compound,

[0082] More preferably, the compound contains (a) at least one selected from the group consisting of a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having 10 carbon atoms in a 2-hydroxyalkyl group, a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having 12 carbon atoms in a 2-hydroxyalkyl group, N-hydroxyethyl-N-2-hydroxyalkylamine having 10 carbon atoms in a 2-hydroxyalkyl group, N-hydroxyethyl-N-2-hydroxyalkylamine having 12 carbon atoms in a 2-hydroxyalkyl group, N-hydroxyethyl-N-2-hydroxyalkylamine having 14 carbon atoms in a 2-hydroxyalkyl group, N-hydroxyethyl-N-2-hydroxyalkylamine having 16 carbon atoms in a 2-hydroxyalkyl group, N-hydroxyethyl-N-2-hydroxyalkylamine having 17 carbon atoms in a 2-hydroxyalkyl group, N-hydroxyethyl-N-2-hydroxyalkylamine having 18 carbon atoms in a 2-hydroxyalkyl group, lauramine, hexadecylamine, stearylamine, oleylamine, dimethyl laurylamine and polyoxyethylene laurylamine,

[0083] More preferably, it contains (b) a mixture selected from (bi) a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having 10 carbon atoms in the 2-hydroxyalkyl group and a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having 12 carbon atoms in a weight ratio of 50:50 (for example, EC-4 manufactured by Kitakyu Chemical Co., Ltd.), (b-ii) a mixture of N-hydroxyethyl-N-2-hydroxyalkylamine having 10 carbon atoms in the 2-hydroxyalkyl group and N-hydroxyethyl-N-2-hydroxyalkylamine having 12 carbon atoms in the 2-hydroxyalkyl group (for example, DUSPER 125B manufactured by Miyoshi Oil & Fats Co., Ltd.), (b-iii) N-hydroxyethyl-N-2-hydroxyalkylamine having 14 carbon atoms in the 2-hydroxyalkyl group (for example, Antista 80S), (b-iv) a mixture of N-hydroxyethyl-N-2-hydroxyalkylamine having 16 carbon atoms in the 2-hydroxyalkyl group, N-hydroxyethyl-N-2-hydroxyalkylamine having 17 carbon atoms in the 2-hydroxyalkyl group and N-hydroxyethyl-N-2-hydroxyalkylamine having 18 carbon atoms (for example, Antista 80FS manufactured by TANAKA Chemical Research Institute), (bv) laurylamine, (b-vi) hexadecylamine, (b-vii) stearylamine, (b-viii) oleylamine, (b-ix) dimethyl laurylamine and (bx) polyoxyethylene laurylamine,

[0084] Particularly preferably, it contains one or more selected from the group consisting of (c) a mixture of (ci) a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having a 2-hydroxyalkyl group with 10 carbon atoms and a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having a 2-hydroxyalkyl group with 12 carbon atoms in a weight ratio of 50:50, (c-ii) N-hydroxyethyl-N-2-hydroxyalkylamine having a 2-hydroxyalkyl group with 14 carbon atoms, and (c-iii) laurylamine.

[0085] In one embodiment of the present invention, the content of component (A) is not particularly limited. In this specification, "the content of component (A)" refers to the total content of all substances contained in the foamable resin particles as component (A). For example, when the foamable resin particles contain N-hydroxyethyl-N-2-hydroxyalkylamine, a salt of N-hydroxyethyl-N-2-hydroxyalkylamine, an alkylamine compound without a hydroxyl group, and an alkenylamine compound without a hydroxyl group as component (A), the "content of component (A)" in the foamable resin particles refers to "the total amount of the content of N-hydroxyethyl-N-2-hydroxyalkylamine, the content of the salt of N-hydroxyethyl-N-2-hydroxyalkylamine, the content of the alkylamine compound without a hydroxyl group, and the content of the alkenylamine compound without a hydroxyl group".

[0086] When "N-hydroxyethyl-N-2-hydroxyalkylamine" is a mixture of a plurality of compounds having different numbers of carbon atoms in the 2-hydroxyalkyl group, "the content of N-hydroxyethyl-N-2-hydroxyalkylamine" refers to the total content of the mixture. When "N-hydroxyethyl-N-2-hydroxyalkylamine salt" is a mixture of a plurality of compounds having different numbers of carbon atoms in the 2-hydroxyalkyl group, "the content of N-hydroxyethyl-N-2-hydroxyalkylamine salt" refers to the total content of the mixture.

[0087] In the case where the alkylamine compound X is a mixture of a plurality of compounds having different numbers of carbon atoms in the alkyl group, the "content of the alkylamine compound (alkylamine compound X) not having a hydroxyl group" refers to the total content of the mixture. In the case where the alkenylamine compound X is a mixture of a plurality of compounds having different numbers of carbon atoms in the alkenyl group, the "content of the alkenylamine compound (alkenylamine compound X) not having a hydroxyl group" refers to the total content of the mixture.

[0088] The content of component (A) is preferably 0.03 to 0.50 parts by weight, more preferably 0.04 to 0.40 parts by weight, further preferably 0.05 to 0.30 parts by weight, and particularly preferably 0.05 to 0.25 parts by weight, relative to 100 parts by weight of the main body of the foamable resin particles. When the content of component (A) is 0.03 parts by weight or more relative to 100 parts by weight of the main body of the foamable resin particles, the antibacterial and antiviral properties of the foamable resin particles are more excellent.

[0089] The foamable resin particles and the foamed particles are each sometimes transported by, for example, air conveying or moved in a pipe. Therefore, the foamable resin particles and the foamed particles are each sometimes required to have excellent fluidity. In addition, the foamable particles and the foamed molded article are each sometimes required to have excellent weldability. When the content of component (A) is less than 0.50 parts by weight relative to 100 parts by weight of the foamable resin particle body, there are (i) advantages of excellent fluidity of the foamable resin particles and the foamed particles and / or (ii) advantages of excellent weldability of the foamable particles and the foamed molded article.

[0090] The case where the foamable resin particles contain N-hydroxyethyl-N-2-hydroxyalkylamine as the (A) component is described. The content of the aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine is preferably 0.03 to 0.50 parts by weight relative to 100 parts by weight of the foamable resin particle body. If the content of the aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine is 0.03 parts by weight or more relative to 100 parts by weight of the foamable resin particle body, the antibacterial and antiviral properties of the foamed molded body are improved, so it is preferred. If it is 0.50 parts by weight or less, the fluidity of the foamed particles is excellent, so it is preferred. Furthermore, the inventors have newly discovered the following insights during the in-depth study: when the content of the aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine is 0.50 parts by weight or less, in the process of forming the foamed particles into a foamed molded body by foaming the foamable resin particles, the effect of fusing the foamed particles to each other is improved, and the fusing property of the foamed particles constituting the foamed molded body is improved. The content of the N-hydroxyethyl-N-2-hydroxyalkylamine is more preferably 0.04 to 0.40 parts by weight, further preferably 0.05 to 0.30 parts by weight, and particularly preferably 0.05 to 0.25 parts by weight, based on 100 parts by weight of the expandable resin particle body.

[0091] The case where the foamable resin particles contain N-hydroxyethyl-N-2-hydroxyalkylamine salt as the (A) component is described. The content of the aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine salt is preferably 0.0005 to 0.013 parts by weight relative to 100 parts by weight of the foamable resin particle body. If the content of the aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine salt is 0.0005 parts by weight or more relative to 100 parts by weight of the foamable resin particle body, the antibacterial and antiviral properties of the foamed molded body are improved, so it is preferred. If it is 0.013 parts by weight or less, the fluidity of the foamed particles is excellent, so it is preferred. The lower limit of the content of the aforementioned N-hydroxyethyl-N-2-hydroxyalkylamine salt is more preferably 0.001 parts by weight or more, further preferably 0.002 parts by weight or more, and particularly preferably 0.003 parts by weight or more. The upper limit of the content of the N-hydroxyethyl-N-2-hydroxyalkylamine salt is more preferably 0.012 parts by weight or less, more preferably 0.011 parts by weight or less, and even more preferably 0.010 parts by weight or less.

[0092] The case where the foamable resin particles contain one or more selected from the group consisting of alkylamine compounds X and alkenylamine compounds X as component (A) is described. The total content of the alkylamine compound X and the alkenylamine compound X in the present foamable resin particles is preferably 0.03 to 0.50 parts by weight relative to 100 parts by weight of the foamable resin particle body. When the total content of the alkylamine compound X and the alkenylamine compound X is 0.03 parts by weight or more relative to 100 parts by weight of the foamable resin particle body, the antibacterial property of the obtained foamable resin particles is improved, so it is preferred. Among the compounds contained in the alkylamine compound X and the alkenylamine compound X, there are many compounds that are liquid at room temperature (e.g., 20°C). For example, laurylamine, oleylamine, dimethyl laurylamine, and polyoxyethylene laurylamine are liquid at room temperature. There is a tendency that the less the content (coating amount) of the compound that is liquid at room temperature, the better the fluidity of the foamable resin particles. Therefore, when the total content of the alkylamine compound X and the alkenylamine compound X is 0.50 parts by weight or less based on 100 parts by weight of the expandable resin particle body, there is an advantage that the expandable resin particles and the expandable particles obtained therefrom have excellent fluidity.

[0093] Furthermore, the present inventors have newly discovered the following knowledge in the course of in-depth studies: when the total content of the alkylamine compound X and the alkenylamine compound X is 0.50 parts by weight or less relative to 100 parts by weight of the foamable resin particle body, in the step of molding the foamable particles into a foamed molded body by foaming the foamable resin particles, the effect of fusing the foamable particles to each other is enhanced, and the fusing property of the foamable particles constituting the foamed molded body is improved.

[0094] From the viewpoint of the antibacterial property of the obtained foamable resin particles, etc., the lower limit of the total content of the alkylamine compound X and the alkenylamine compound X is more preferably 0.04 parts by weight or more, and further preferably 0.05 parts by weight or more, relative to 100 parts by weight of the foamable resin particle body. In addition, from the viewpoint of (a) the fluidity of the foamable resin particles and the foamed particles and (b) the weldability of the foamed molded article, the upper limit of the total content of the alkylamine compound X and the alkenylamine compound X is more preferably 0.40 parts by weight or less, further preferably 0.30 parts by weight or less, and particularly preferably 0.25 parts by weight or less, relative to 100 parts by weight of the foamable resin particle body.

[0095] (2-7. (B) Component)

[0096] The present expandable resin particles contain one or more selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol and polybutylene glycol as component (B). By coating the component (B) on the surface of the expandable resin particle body, expandable resin particles containing the component (B) on the surface of the expandable resin particle can be obtained.

[0097] The (B) component coated on the foamable resin particle body is substantially entirely attached to the foamable resin particle body and is contained in the foamable resin particle. That is, the (B) component functions as an external additive, and the (B) component can also be referred to as an external additive. In addition, the "content" of the (B) component in the foamable resin particle can also be referred to as the "coating amount" of the (B) component on the foamable resin particle body.

[0098] The present inventors independently found the following new knowledge during intensive studies: when the expandable resin particles contain the components (A) and (B), the expandable resin particles surprisingly have more excellent antibacterial and antiviral properties.

[0099] In addition, the inventors independently discovered the following new insights during the course of in-depth research: Even in the case where the component (B) is not included but the component (A) alone (for example, N-hydroxyethyl-N-2-hydroxyalkylamine alone, alkylamine compound X alone, or alkenylamine compound X alone) is included, the foamable resin particles can also exert antibacterial and / or antiviral properties. However, compared to the case where the foamable resin particles contain the component (A) alone, in the case where the foamable resin particles contain both the component (A) and the component (B), even if the content of the component (A) is very small, the same degree of antibacterial and / or antiviral properties can be exerted. The lower the content of the component (A), the more advantages there are in (i) the better the fluidity of the foamable resin particles and the foamed particles and / or (ii) the better the weldability between the foamed particles and the foamed molded body. That is, compared with the case where the foamable resin particles contain the (A) component alone, in the case where the foamable resin particles contain both the (A) component and the (B) component, by setting the content of the (A) component to be smaller, the foamable resin particles have excellent antibacterial and / or excellent antiviral properties, and have the following advantages: (i) the foamable resin particles and the foamed particles have excellent fluidity, and / or (ii) the foamed particles and the foamed molded body have excellent welding properties.

[0100] The reason why the antibacterial and antiviral properties of the foamable resin particles are expressed by the (B) component is not clear, but it is speculated as follows: by using the (B) component, the fixation of the (A) component (the bonding between the foamable resin particle body and the (A) component) is mainly enhanced, and the peeling of the (A) component from the foamable resin particles in the (pre) foaming process and the molding process can be suppressed. Therefore, it is believed that the amount of the (A) component that remains on the surface of the foaming particles and / or the foaming molding and exerts antibacterial properties increases, showing antibacterial and antiviral properties. It should be noted that the present invention is not limited to this speculation.

[0101] The ricinoleic acid derivatives are not particularly limited, and examples thereof include organic compounds such as triglycerides, amides, and esters whose main fatty acid composition is ricinoleic acid. In addition, castor oil is a triglyceride, and ricinoleic acid accounts for about 90% of its fatty acid composition. Therefore, castor oil is also included in the ricinoleic acid derivatives.

[0102] It should be noted that ricinoleic acid is an ω-9 fatty acid with 18 carbon atoms and a hydroxyl group, and is an unsaturated fatty acid having a carbon-carbon double bond at the ω-9 position (the ninth position from the methyl end of the fatty acid (also referred to as the "ω end")) and a hydroxyl group on the seventh carbon from the methyl end of the fatty acid. A saturated fatty acid having a hydroxyl group on the seventh carbon from the methyl end of the fatty acid, 18 carbon atoms but no carbon-carbon double bond, similarly to ricinoleic acid, is 12-hydroxystearic acid, which is a substance completely different from ricinoleic acid. In this specification, a "ricinoleic acid derivative" refers to a substance having at least a carbon-carbon double bond. "Hydrogenated castor oil" is a substance obtained by hydrogenating castor oil, and as a structure, it is a triglyceride whose fatty acid composition is mainly composed of 12-hydroxystearic acid. Therefore, "hydrogenated castor oil" is not included in ricinoleic acid derivatives.

[0103] The present inventors have conducted studies and found that, when castor oil is used together with component (A), expandable resin particles having excellent antibacterial properties are obtained, but when hydrogenated castor oil is used together with component (A), expandable resin particles having excellent antibacterial properties are not obtained.

[0104] It should be noted that oleic acid is an ω-9 fatty acid having 18 carbon atoms, and is an unsaturated fatty acid having a carbon-carbon double bond at the ω-9 position (the ninth position from the methyl end (also referred to as the "ω end") of the fatty acid). A saturated fatty acid having 18 carbon atoms like oleic acid but not having a carbon-carbon double bond is hydroxystearic acid, which is a substance completely different from oleic acid. In this specification, an "oleic acid derivative" refers to a substance having at least a carbon-carbon double bond.

[0105] The oleic acid derivative is not particularly limited, and examples thereof include organic compounds such as triglycerides, amides, and esters, the main component of which is oleic acid in the fatty acid composition.

[0106] Polypropylene glycol has a structural unit of propylene oxide (-C3H6O-). In this specification, "polypropylene glycol" refers to a compound in which the mole % of the structural unit of propylene oxide (-C3H6O-) is the largest among the structural units constituting the compound. For example, a polyalkylene glycol which is a copolymer formed of ethylene oxide and propylene oxide and in which the mole % of the structural unit of propylene oxide is greater than the mole % of the structural unit of ethylene oxide (-C2H4O-) is regarded as "polypropylene glycol" in this specification.

[0107] In one embodiment of the present invention, the number average molecular weight of polypropylene glycol is 800 or more. The larger the number average molecular weight of polypropylene glycol, the lower the solubility in water. Polypropylene glycol with a number average molecular weight of 800 or more is insoluble in water. Therefore, in the case where the number average molecular weight of polypropylene glycol contained in the foamable resin particles is 800 or more, even after the foaming of the foamable resin particles using water vapor and the molding of the foamed particles using water vapor, a large amount of polypropylene glycol will remain in the foamed particles and the foamed molded body, so there is an advantage of excellent antibacterial and antiviral properties of the foamed particles and the foamed molded body. The number average molecular weight of polypropylene glycol is preferably 900 or more, more preferably 1000 or more, further preferably 1500 or more, and particularly preferably 2000 or more. The number average molecular weight of polypropylene glycol can be measured by the method of MALDI ToF-MS. In addition, when polypropylene glycol is a commercially available product, the information on the number average molecular weight can be obtained from the data table of the product.

[0108] The upper limit of the number average molecular weight of polypropylene glycol is not particularly limited, but is preferably 4500 or less, more preferably 4250 or less, more preferably 4000 or less, further preferably 3500 or less, and particularly preferably 3000 or less, from the viewpoint of preventing the viscosity of the external additive from becoming too high and facilitating handling.

[0109] Polybutylene glycol has a structural unit of butylene oxide (-C4H8O-). In this specification, "polybutylene glycol" refers to a compound in which the mol% of the structural unit of butylene oxide (-C4H8O-) is the largest among the structural units constituting the compound. For example, in the case of a polyalkylene glycol that is a copolymer formed of ethylene oxide, propylene oxide and butylene oxide, (i) the polyalkylene glycol in which the mol% of the structural unit of propylene oxide is the largest is regarded as "polypropylene glycol" in this specification, and (ii) the polyalkylene glycol in which the mol% of the structural unit of butylene oxide is the largest is regarded as "polybutylene glycol" in this specification.

[0110] In one embodiment of the present invention, the number average molecular weight of polybutylene glycol is 300 or more. The larger the number average molecular weight of polybutylene glycol, the lower the solubility in water. Polybutylene glycol with a number average molecular weight of more than 300 is insoluble in water. Therefore, in the case where the number average molecular weight of the polybutylene glycol contained in the foamable resin particles is more than 300, even after the foaming of the foamable resin particles using water vapor and the molding of the foamed particles using water vapor, a large amount of polybutylene glycol will remain in the foamed particles and the foamed molded body, so there is the advantage of excellent antibacterial and antiviral properties of the foamed particles and the foamed molded body. The number average molecular weight of polybutylene glycol is preferably more than 400, more preferably more than 500, more preferably more than 600, more preferably more than 700, further preferably more than 1000, further preferably more than 1500, and particularly preferably more than 2000. The number average molecular weight of polybutylene glycol can be determined by the method of MALDI ToF-MS. When polytetramethylene glycol is a commercially available product, information on the number average molecular weight can be obtained from the data sheet of the product.

[0111] The upper limit of the number average molecular weight of polytetramethylene glycol is not particularly limited, but is preferably 5000 or less, more preferably 4500 or less, more preferably 4000 or less, further preferably 3500 or less, and particularly preferably 3000 or less from the viewpoint of preventing the viscosity of the external additive from becoming too high and facilitating handling.

[0112] The expandable resin particles preferably further contain at least one selected from the group consisting of castor oil, polypropylene glycol and polybutylene glycol as the component (B), from the viewpoint of further improving the antibacterial and antiviral properties of the expandable resin particles.

[0113] In one embodiment of the present invention, the content of component (B) is not particularly limited. In this specification, "the content of component (B)" refers to the total content of all substances contained as component (B) in the foamable resin particles. For example, when the foamable resin particles contain castor oil, polypropylene glycol and polybutylene glycol as components (B), the "content of component (B)" in the foamable resin particles refers to "the total amount of the content of castor oil, the content of polypropylene glycol and the content of polybutylene glycol".

[0114] Relative to 100 parts by weight of the main body of the foamable resin particles, the content of the component (B) is preferably 0.03 to 0.30 parts by weight, more preferably 0.04 to 0.30 parts by weight, more preferably 0.05 to 0.30 parts by weight, more preferably 0.07 to 0.25 parts by weight, further preferably 0.10 to 0.20 parts by weight, and particularly preferably 0.12 to 0.18 parts by weight. When the content of the component (B) is 0.03 parts by weight or more relative to 100 parts by weight of the main body of the foamable resin particles, the foamable resin particles have the advantage of having better antibacterial and antiviral properties. Among the compounds contained in the component (B), there are many compounds that are liquid at room temperature (e.g., 20°C). For example, castor oil, polypropylene glycol, and polybutylene glycol are all liquid at room temperature. When the content of the component (B) is 0.30 parts by weight or less based on 100 parts by weight of the expandable resin particle body, there is an advantage that the expandable resin particles and the expandable particles have excellent fluidity.

[0115] (2-8. Other external additives)

[0116] The foamable resin particles may contain, in addition to component (A) and component (B), known external additives such as anti-adhesive agents (e.g., metal salts of higher fatty acids such as zinc stearate and magnesium stearate), antistatic agents, water repellents, and welding accelerators (hereinafter also referred to as "other external additives") on the surface of the foamable resin particles within a range that does not hinder the effect of one embodiment of the present invention. For example, as welding accelerators, (i) castor wax (hydroxystearic acid triglyceride) that is solid at room temperature, (ii) triesters, diesters, and monoesters of higher fatty acids such as stearic acid sorbitan esters, and (iii) sucrose esters may be cited. In addition, zinc stearate and magnesium stearate are solid at room temperature.

[0117] The period of adding (using) these other external additives is not particularly limited. When the other external additives are solid external additives at room temperature, it is preferred to apply the components (A) and (B) that are liquid at room temperature and the components (A) and (B) that are applied in the form of an aqueous solution to the foamable resin particle body, dry as needed, and then add the other external additives. The components (A) and (B) that are solid at room temperature and applied in a solid state can be applied together with other external additives that are solid at room temperature.

[0118] The inventors independently discovered the following new insights during the process of in-depth research: the greater the ratio of the content of the external additive that is solid at room temperature (e.g., 20°C) to the content of the external additive that is liquid at room temperature (e.g., 20°C) in the foamable resin particles (the content of the external additive that is solid at room temperature / the content of the external additive that is liquid at room temperature), the better the foamable resin particles and the fluidity of the foamable particles. It should be noted that for "external additives that are solid at room temperature but added (coated) in the state of aqueous solution" (e.g., salts of N-hydroxyethyl-N-2-hydroxyalkylamine), after addition (coating), by drying the foamable resin particles, only the solid external additives remain on the surface of the foamable resin particles, so they are also included in the "external additives that are solid at room temperature". In addition, for external additives that are liquid at room temperature, as long as they are liquid at room temperature, they include not only components (A) and (B), but also other external additives. In addition, for external additives that are solid at room temperature, as long as they are solid at room temperature, they include not only components (A) and (B), but also other external additives.

[0119] From the viewpoint of the fluidity of the foamable resin particles and the foamable particles, the ratio of the content of the external additive that is solid at room temperature to the content of the external additive that is liquid at room temperature (the content of the external additive that is solid at room temperature / the content of the external additive that is liquid at room temperature) in the foamable resin particles is preferably 1.80 or more, more preferably 1.90 or more, more preferably 2.00 or more, more preferably 2.10 or more, more preferably 2.20 or more, more preferably 2.30 or more, further preferably 2.40 or more, and particularly preferably 2.50 or more. The upper limit of the above ratio is not particularly limited, for example, 8.50 or less.

[0120] The present inventors independently discovered the following new insight during the process of in-depth research: the less the content of the external additive that is solid at room temperature in the foamable resin particles is, the better the weldability between the foamable particles and the foamed molded body is. From the viewpoint of the weldability between the foamable particles and the foamed molded body, the content of the external additive that is solid at room temperature in the foamable resin particles is preferably 0.750 parts by weight or less, more preferably 0.730 parts by weight or less, more preferably 0.700 parts by weight or less, more preferably 0.680 parts by weight or less, more preferably 0.650 parts by weight or less, further preferably 0.630 parts by weight or less, further preferably 0.600 parts by weight or less, and particularly preferably 0 to 0.0600 parts by weight. The content of the external additive that is solid at room temperature in the foamable resin particles may also be 0 parts by weight relative to 100 parts by weight of the foamable resin particles.

[0121] [3. Method for producing expandable resin particles]

[0122] A method for producing expandable resin particles according to one embodiment of the present invention is a method for producing expandable resin particles comprising a base resin and a foaming agent, the method comprising a coating step of coating (A) an amine compound and (B) one or more selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol, and polybutylene glycol on the surface of the main body of the expandable resin particles, wherein the base resin comprises a styrene-based resin, the number average molecular weight of the polypropylene glycol is 800 or more, and the number average molecular weight of the polybutylene glycol is 300 or more. Here, in the present specification, "coating" also includes adding to the main body of the expandable resin particles and mixing them so that the surface of the expandable resin particles contains the amine compound.

[0123] In this specification, "the method for producing expandable resin particles according to one embodiment of the present invention" may be referred to as "the present production method".

[0124] Hereinafter, each aspect related to the present production method will be described. Except for matters described in detail below, the description of the section [2. Expandable resin particles] is appropriately cited.

[0125] (Coating process)

[0126] As a coating process, for example, there can be cited a method (process) of adding component (A), component (B) and other external additives added as needed to the main body of the foamable resin particles, and mixing the obtained mixture. It is also possible to add several components of component (A), component (B) and other external additives added as needed to the main body of the foamable resin particles, mix the obtained mixture, add the remaining components to the obtained mixture, and further mix the obtained mixture. That is, the order of adding component (A), component (B) and other external additives added as needed to the main body of the foamable resin particles is not particularly limited, and they can be added in any order. In addition, component (A), component (B) and other external additives can be added in the state of each component itself (for example, solid state), or can be added in the state of a solution dissolved in any solvent.

[0127] It is preferred to apply the component (A), the component (B) and other external additives as required on the surface of the foamable resin particle body as uniformly as possible. Therefore, in mixing the foamable resin particle body with the component (A), the component (B) and other external additives used as required, it is preferred to use a mixing device that can uniformly mix these external additives.

[0128] Examples of the mixing device include: (a) mixers such as a high-speed mixer, a Nauta mixer, a universal mixer, a Ploughshare mixer, an Apex mixer, a Henschel mixer, and a Loedige mixer; and (b) stirrers such as a ribbon mixer and a drum mixer.

[0129] The conditions such as the mixing time in the mixing equipment may be adjusted by taking into consideration (a) the mixing capacity; and (b) the types and coating amounts of external additives such as the (A) component and the (B) component.

[0130] The foamable resin particle body can be obtained by impregnating the base resin obtained by polymerization with a foaming agent as described in the above-mentioned (2-5. Method for producing the foamable resin particle body). The polymerization of the base resin and the impregnation of the foaming agent can be carried out in an aqueous suspension. Therefore, the obtained foamable resin particle body sometimes has water attached to the surface. Before coating the (A) component, the (B) component and other external additives as needed on the foamable resin particle body, the foamable resin particle body can be dehydrated or dried.

[0131] When adding the external additive in the form of an aqueous solution to the expandable resin particle body, the external additive may be added after the expandable resin particle body is dehydrated or dried, for example, but the external additive may be added during dehydration.

[0132] As the N-hydroxyethyl-N-2-hydroxyalkylamine salt of the component (A), there are many compounds that are solid at room temperature. When using an N-hydroxyethyl-N-2-hydroxyalkylamine salt that is solid at room temperature, from the viewpoint of coating (containing) the component (A) as uniformly as possible on the main body of the foamable resin particles, it is preferred to prepare an aqueous solution of the N-hydroxyethyl-N-2-hydroxyalkylamine salt that is solid at room temperature and then coat the aqueous solution of the N-hydroxyethyl-N-2-hydroxyalkylamine salt on the main body of the foamable resin particles.

[0133] The case of adding (coating) (a) solid components (A) and (B) and other external additives used as needed, and (b) liquid or solution components (A) and (B) and other external additives used as needed to the main body of the foamable resin particles is described. In this case, from the viewpoint of coating the components (A) and (B) and other external additives used as needed to the main body of the foamable resin particles as uniformly as possible and obtaining foamable resin particles with excellent antibacterial, antiviral and fluidity properties, it is preferred that (1) the components (A) and (B) and other external additives used as needed in liquid or solution states are added (coated) to the main body of the foamable resin particles, and (2) the components (A) and (B) and other external additives used as needed in solid states are added (coated) to the obtained foamable resin particle main body (foamable resin particles). The following describes the cases of adding (coating) (a) solid component (A), component (B) and other external additives used as needed, (b) liquid component (A), component (B) and other external additives used as needed, and (c) solution component (A), component (B) and other external additives used as needed to the main body of the foamable resin particles. In this case, from the viewpoint of coating the (A) component, the (B) component and other external additives used as needed on the foamable resin particle body as uniformly as possible and obtaining foamable resin particles having excellent antibacterial properties, antiviral properties and fluidity, it is preferred that (1) the (A) component, the (B) component and other external additives used as needed in a solution state are added (coated) to the foamable resin particle body, and then (2) the obtained foamable resin particle body (foamable resin particles) is optionally dried, (3) the (A) component, the (B) component and other external additives used as needed in a liquid state are then added (coated) to the foamable resin particle body, and (4) the (A) component, the (B) component and other external additives used as needed in a solid state are added (coated) to the finally obtained foamable resin particle body (foamable resin particles).

[0134] In the present production method, the coating step is preferably performed in order from the following steps (1) to (4) (wherein step (2) is an optional step):

[0135] (1) coating the surface of the expandable resin particle body with an aqueous solution of a salt of N-hydroxyethyl-N-2-hydroxyalkylamine as the component (A) (preferably a mixture of a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having 10 carbon atoms and a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having 12 carbon atoms in a weight ratio of 50:50),

[0136] (2) optionally drying the expandable resin particle body,

[0137] (3) applying component (A) which is liquid at room temperature (preferably at least one selected from the group consisting of laurylamine, oleylamine, dimethyl laurylamine and polyoxyethylene laurylamine) and component (B) which is liquid at room temperature (preferably at least one selected from the group consisting of castor oil, polypropylene glycol and polybutylene glycol),

[0138] (4) Applying component (A) which is solid at room temperature (preferably one or more selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine (preferably a mixture of N-hydroxyethyl-N-2-hydroxyalkylamine having a 2-hydroxyalkyl group with 10 carbon atoms and N-hydroxyethyl-N-2-hydroxyalkylamine having a 2-hydroxyalkyl group with 12 carbon atoms, N-hydroxyethyl-N-2-hydroxyalkylamine having a 2-hydroxyalkyl group with 14 carbon atoms, and a mixture of N-hydroxyethyl-N-2-hydroxyalkylamine having a 2-hydroxyalkyl group with 16 carbon atoms, N-hydroxyethyl-N-2-hydroxyalkylamine having a 2-hydroxyalkyl group with 17 carbon atoms and N-hydroxyethyl-N-2-hydroxyalkylamine having a 2-hydroxyalkyl group with 18 carbon atoms), one or more selected from the group consisting of hexadecylamine and stearylamine) and optionally other external additives which are solid at room temperature (preferably one or more selected from the group consisting of zinc stearate and castor wax).

[0139] [3. Foaming particles]

[0140] The foamed beads according to one embodiment of the present invention are obtained by foaming the present foamable resin beads described in the above section [2. Foamable resin particles].

[0141] Since the foamable resin particles have the aforementioned structure, the foamable particles have the advantage of excellent antibacterial properties. In addition, since the foamable particles have the aforementioned structure, they also have the advantage of being able to provide a foamed molded product with excellent antibacterial properties. The foamable particles are further preferably excellent in antiviral properties. Foamable particles with excellent antiviral properties can be obtained by foaming foamable resin particles with excellent antiviral properties. Foamable particles with excellent antiviral properties can provide a foamed molded product with excellent antiviral properties. The foamable particles are further preferably excellent in fluidity. Foamable particles with excellent fluidity can be obtained by foaming foamable resin particles with excellent fluidity. The foamable particles are further preferably excellent in weldability. Foamable particles with excellent weldability can be obtained by foaming foamable resin particles with excellent weldability. Foamable particles with excellent weldability can provide a foamed molded product with excellent weldability.

[0142] Here, when obtaining a foamed molded article from foamable resin particles, the foamable resin particles are sometimes first foamed to obtain foamed particles, and then the foamed particles are molded to obtain a foamed molded article. Therefore, in the process of obtaining a foamed molded article from foamable resin particles, foaming the foamable resin particles is sometimes referred to as "pre-foaming" or "primary foaming", and the obtained foamed particles are sometimes referred to as "pre-foamed particles" or "primary foamed particles".

[0143] As a method for foaming the foamable resin particles, for example, a common method can be adopted, such as using a cylindrical pre-foaming device, heating the foamable resin particles with a heating medium such as steam to foam them, etc. The device used for foaming the foamable resin particles and the foaming conditions can be appropriately set according to the composition of the foamable resin particle body and / or the desired expansion ratio, etc., and are not particularly limited.

[0144] The expansion ratio of the foamed particles is not particularly limited, for example, preferably 5 to 80 times, more preferably 10 to 75 times, further preferably 20 to 70 times, and particularly preferably 30 to 65 times. When the expansion ratio (a) of the foamed particles is 5 times or more, the foamed particles have the advantage of being able to provide a lightweight foamed molded body, and when (b) is 80 times or less, the foamed particles have the advantage of being able to provide a foamed molded body with excellent strength. In addition, if it is 80 times or less, the concentration of the antibacterial agent per unit area of ​​the foamed particles will not be too low, so it is preferred. The method for determining the expansion ratio of the foamed particles is described in detail in the following examples.

[0145] The present invention also includes a method for producing foamed beads. The method for producing foamed beads according to one embodiment of the present invention includes: producing foamed resin beads by the method for producing foamed resin beads described above; and foaming the foamed resin beads.

[0146] [4. Foamed molded article]

[0147] The foamed molded article of one embodiment of the present invention is obtained by molding the foamed beads described in the above section [3. Foamed beads]. Here, in the process of obtaining the foamed molded article from the foamed beads, heating the foamed beads to foam them is sometimes referred to as "secondary foaming".

[0148] Since the foamable resin particles and the foaming particles have the aforementioned structure, the foaming molded product has the advantage of excellent antibacterial property. The foaming molded product is further preferably excellent in antiviral property. The foaming molded product having excellent antiviral property can be obtained by molding the foaming particles having excellent antiviral property. The foaming molded product is further preferably excellent in weldability. The foaming molded product having excellent weldability can be obtained by molding the foaming particles having excellent weldability.

[0149] There is no particular limitation on the method for molding the foamed particles, and for example, a common method such as in-mold foam molding can be used. In-mold foam molding refers to a method in which foamed particles are filled in a mold, and a heating medium such as water vapor is blown into the mold to heat the foamed particles, thereby foaming the foamed particles and fusing the foamed particles to each other, thereby obtaining a foamed molded article. The molding of foamed particles based on the in-mold foam molding method is sometimes referred to as in-mold molding. The foamed molded article of one embodiment of the present invention can be formed by in-mold molding of the foamed particles described in the aforementioned [3. Foamed particles].

[0150] The apparatus used for molding the foamed beads and the molding conditions may be appropriately set according to the composition of the foamable resin particle body, the composition of the foamed beads, and / or the desired expansion ratio, and are not particularly limited.

[0151] The present invention also includes a method for producing a foamed molded article. The method for producing a foamed molded article according to one embodiment of the present invention includes: a step of producing foamed beads by the aforementioned method for producing foamed beads; and a step of molding the foamed beads.

[0152] [5. Application]

[0153] The foamable resin particles, foamable particles and foaming molded article of one embodiment of the present invention have the advantage of excellent antibacterial property. In addition, one embodiment of the present invention also has the advantages of being able to provide (i) foamable resin particles, foamable particles and foaming molded article with excellent antiviral property, (ii) foamable resin particles and foaming particles with excellent fluidity, (iii) foamable particles and foaming molded article with excellent weldability and (iv) lightweight and foaming molded article with excellent cushioning and thermal insulation. Therefore, this foamable resin particle, this foamable particle and this foaming molded article can be suitable for packaging materials (trays) of food containers, various packaging materials, building civil engineering components, automobile components, insulation materials of piping, roof insulation materials, solar energy system insulation materials, water heater insulation materials, etc. This foamable resin particle, this foamable particle and this foaming molded article are particularly suitable for packaging materials (trays) of food containers, various packaging materials, building civil engineering components, automobile components, etc.

[0154] One embodiment of the present invention may have the following configuration.

[0155] [1] A foamable resin particle comprising a base resin and a foaming agent, wherein the base resin comprises a styrene-based resin, and the surface of the foamable resin particle contains (A) an amine compound and (B) at least one selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol and polybutylene glycol, wherein the number average molecular weight of the polypropylene glycol is 800 or more, and the number average molecular weight of the polybutylene glycol is 300 or more.

[0156] [2] The expandable resin particles according to [1], wherein the content of the component (A) is 0.03 to 0.50 parts by weight, and the content of the component (b) is 0.03 to 0.30 parts by weight, based on 100 parts by weight of the expandable resin particle body.

[0157] [3] The expandable resin particles according to [1] or [2], wherein the component (A) comprises one or more selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine, a salt of N-hydroxyethyl-N-2-hydroxyalkylamine, an alkylamine compound having no hydroxyl group, and an alkenylamine compound having no hydroxyl group.

[0158] [4] The expandable resin particles according to any one of [1] to [3], wherein the component (B) comprises one or more selected from the group consisting of castor oil, polypropylene glycol, and polybutylene glycol.

[0159] [5] The expandable resin particles according to any one of [1] to [4], wherein the number average molecular weight of the polypropylene glycol is 4500 or less.

[0160] [6] The expandable resin particles according to any one of [1] to [5], wherein the number average molecular weight of the polytetramethylene glycol is 5,000 or less.

[0161] [7] The expandable resin particles according to [4], wherein the polypropylene glycol and the polybutylene glycol are liquid at room temperature.

[0162] [8] Foamed beads obtained by foaming the foamable resin particles according to any one of [1] to [7].

[0163] [9] A foamed molded product obtained by molding the foamed particles described in [8].

[0164]

[10] A method for producing expandable resin particles, which is a method for producing expandable resin particles comprising a base resin and a foaming agent, comprising a coating step, wherein the coating step comprises coating (A) an amine compound and (B) one or more selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol and polybutylene glycol on the surface of the expandable resin particle body, wherein the base resin comprises a styrene-based resin, the number average molecular weight of the polypropylene glycol is not less than 800, and the number average molecular weight of the polybutylene glycol is not less than 300.

[0165] Example

[0166] Hereinafter, the present invention will be described in further detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[0167] The methods for producing the expanded beads and expanded molded articles in the Examples and Comparative Examples, and various measuring methods and evaluation methods are as follows: Unless otherwise specified, "parts" and "%" are by weight (parts by weight and % by weight).

[0168] <Evaluation of Powder Peeling of Expandable Resin Particles>

[0169] The powder peeling of the expandable resin particles is evaluated by the powder peeling rate of the expandable resin particles. The powder peeling rate of the expandable resin particles is calculated according to the following steps:

[0170] <Equipment and conditions>

[0171] Device: Electric sieve DY-50

[0172] Net: SUS net (mesh: 355μm, 42 mesh, )

[0173] Weight of foamable resin particles: 1kg

[0174] Sieving time: 2 minutes.

[0175] <Method>

[0176] Weigh 1 kg of expandable resin particles and place them on an electric sieve. Sieve for 4 minutes. Recover the powder that passes through the mesh (mesh) of the sieve and falls under the sieve. Remove the expandable resin particles if they are mixed in the recyclate. Measure the weight of the recovered powder and use the value obtained as the stripping amount. Calculate the stripping rate using the following formula.

[0177] Stripping rate [%] = Amount of powder passing through the sieve / Total amount of external additives added × 100

[0178] Here, "the total amount of external additives added" refers to the total amount of zinc stearate, castor wax, salt of N-hydroxyethyl-N-2-hydroxyalkylamine, N-hydroxyethyl-N-2-hydroxyalkylamine, laurylamine and liquid external additives used in the production of 1 kg of expandable resin particles supplied to the electric sieve.

[0179] The powder peeling of the expandable resin particles was evaluated from the obtained peeling ratio based on the following criteria: It should be noted that a smaller peeling ratio means less powder peeling, that is, more excellent powder peeling.

[0180] A score of "1" or above is considered a pass.

[0181] 1: Less than 10% by weight

[0182] 0: 10% by weight or more

[0183] <Manufacturing of Foamed Beads>

[0184] The foamable resin particles were placed in a pressurized pre-foaming machine (manufactured by Daikai Industry Co., Ltd., GH-100). Then, water vapor was used as a heating medium and the blowing steam pressure was set to 0.1 MPa to heat the foamable resin particles, thereby foaming the foamable resin particles to a foaming ratio (volume ratio) of 60 times to obtain foamable particles.

[0185] <Expansion ratio (volume ratio) of foamed particles>

[0186] Determine the expansion ratio of foamed particles according to the following steps:

[0187] (1) Weigh 10g of foamed particles and place them in a 1000cm 3 in a measuring cylinder;

[0188] (2) Determine the volume of 10 g of foamed particles using the scale of the measuring cylinder;

[0189] (3) The expansion ratio of the foamed particles is calculated by the following formula:

[0190] Foaming ratio (cm 3 / g): Volume of foamed particles (cm 3 ) / 10g.

[0191] <Evaluation of Fluidity of Expandable Resin Particles>

[0192] The fluidity of the expandable resin particles is evaluated by the angle of repose. The angle of repose regarding the fluidity of the expandable resin particles is measured by the following steps:

[0193] (1) Prepare a box (rectangular or cubic) with one side as a baffle and an open top surface;

[0194] (2) The expandable resin particles obtained in each example or comparative example are placed in a box so that the upper surface is scraped flat and filled;

[0195] (3) Remove the baffle plate to allow the foamable resin particles to overflow naturally. Then, measure the angle between the slope formed by the foamable resin particles remaining in the box and the bottom surface (horizontal plane) of the box, and refer to this angle as the repose angle (°).

[0196] The fluidity of the expandable resin particles was evaluated from the obtained repose angle based on the following criteria. It should be noted that a smaller repose angle means better fluidity. A value of "1" or higher was considered acceptable.

[0197] 2: Below 30°

[0198] 1: More than 30° and less than 32°

[0199] 0: More than 32°.

[0200] <Evaluation of the fluidity of foamed particles>

[0201] The repose angle is used to evaluate the fluidity of the foamed particles. The foamed particles are placed at room temperature for 6 hours after manufacture and then used for the repose angle measurement within 30 minutes. The repose angle related to the fluidity of the foamed particles is measured in the following order:

[0202] (1) Prepare a box (rectangular or cubic) with one side as a baffle and an open top surface;

[0203] (2) The foamed beads obtained in each embodiment or comparative example are placed in a box so that the upper surface is scraped flat and filled;

[0204] (3) Remove the baffle plate to allow the foamed beads to overflow naturally. Then, measure the angle between the slope formed by the foamed beads remaining in the box and the bottom surface (horizontal plane) of the box, and refer to this angle as the repose angle (°).

[0205] The fluidity of the expanded beads was evaluated from the obtained repose angle based on the following criteria. It should be noted that the smaller the repose angle, the better the fluidity. A value of "1" or higher was considered acceptable.

[0206] 1: Below 32°.

[0207] 0: greater than 32°.

[0208] <Manufacturing of Foam Molded Article>

[0209] The foamed particles were placed at room temperature for 24 hours before being used to make a foamed molded body. The foamed molded body was made using a mold of 450 mm in length × 300 mm in width × 25 mm in depth and a molding machine (KR-57 manufactured by DAISEN Co., Ltd.) according to the following steps:

[0210] (1) Filling the mold with the foamed particles produced by the above method;

[0211] (2) using water vapor as the heating medium, in-mold foaming was performed under the molding conditions of a water vapor blowing time of 22 seconds and a water vapor blowing pressure of 0.08 MPa (gauge pressure);

[0212] (3) After water cooling the mold for 5 seconds, vacuum cooling was performed for 100 seconds;

[0213] (4) Take out from the mold to obtain a foamed molded body.

[0214] <Evaluation of Weldability>

[0215] The weldability of the foamed product is evaluated by the weld rate of the foamed product. The weld rate of the foamed product is calculated according to the following steps:

[0216] (1) breaking the foamed molded body;

[0217] (2) observing the fracture surface and counting (i) the number of all expanded particles present in the observation field and (ii) the number of expanded particles that are broken not at the interface with adjacent expanded particles but at the expanded particles themselves (broken inside the expanded particles);

[0218] (3) Using the obtained results, the welding rate is calculated based on the following formula:

[0219] Welding rate (%)=((the number of foamed beads that are broken not at the interface with the adjacent foamed beads but at the foamed beads themselves) / the total number of foamed beads present in the observation field)×100.

[0220] The fusion bonding property of the foamed molded article was evaluated by the fusion bonding rate obtained based on the following criteria. It should be noted that a larger fusion bonding rate (a larger number) means better fusion bonding property. A value of "1" or higher was considered acceptable.

[0221] 3: The welding rate is more than 90%

[0222] 2: The welding rate is 85% or more and less than 90%

[0223] 1: The welding rate is 70% or more and less than 85%

[0224] 0: The welding rate is less than 70%.

[0225] <Antibacterial evaluation (without pretreatment)>

[0226] According to JIS Z2801, the antibacterial properties of the foamed molded article were evaluated by the following steps:

[0227] (1) The bacteria (Escherichia coli: E. coli JM109) in the bacterial solution became 10 4 pcs / ml~10 5 Prepare bacterial solution in the form of 100 cells / ml;

[0228] (2) 0.4 ml of the bacterial solution prepared in (1) was dripped onto the foamed molded product (foaming ratio: 60 times) to be evaluated, and a PP (polypropylene) film (4×4 cm) sterilized by UV lamp was attached to the area where the bacterial solution was dripped. Then, the foamed molded product attached with the PP film was placed in a culture dish and covered with a lid;

[0229] (3) In a covered petri dish, the bacteria added onto the foamed molded article were cultured at 35°C for 24 hours;

[0230] (4) After the incubation, the PP film was removed, 10 ml of liquid was added dropwise, and the bacteria on the foamed body and the film were recovered;

[0231] (5) diluting 0.02 ml of the recovered solution recovered in step (4) above with 0.18 ml of normal saline;

[0232] (6) Spread 0.1 ml of the diluted solution obtained in (5) on an agar medium and spread it thinly;

[0233] (7) The bacteria in the diluted solution applied to the agar medium in step (6) were cultured at 35°C for 24 hours;

[0234] (8) Determine the number of colonies in the agar medium. (i) If the number of colonies is 50 or less, proceed to (9) below. (ii) If the number of colonies is more than 50, repeat the dilution process from (5) to (7) above until the number of colonies is 50 or less.

[0235] (9) The number of bacteria living on the foam molded article after the culturing in (3) is calculated from the obtained value (colony count) and the dilution ratio.

[0236] As a control, a foamed molded article produced in the same manner as in Example 1 described later except that the (A) component and the (B) component were not added (a foamed molded article obtained by coating only zinc stearate and castor wax as external additives) was used. For this foamed molded article, the number of bacteria surviving on the foamed molded article after the culture in the above-mentioned (3) was calculated according to the same procedures as (1) to (9).

[0237] The number of bacteria calculated for the foaming molded article of the evaluation object is divided by the number of bacteria calculated for the foaming molded article of the control. According to the obtained quotient, the antibacterial property (without pretreatment) is evaluated based on the following benchmarks. It should be noted that the smaller the quotient, the better the antibacterial property. "1" or more is set as qualified.

[0238] 3: The quotient is less than 1 / 10000

[0239] 2: The quotient is greater than 1 / 10000 and less than 1 / 1000

[0240] 1: The quotient is greater than 1 / 1000 and less than 1 / 100

[0241] 0: The quotient is greater than 1 / 100.

[0242] <Antibacterial property evaluation (water resistance)>

[0243] As a pretreatment, the foamed molded article was immersed in warm water at 50°C for 18 hours and then dried. The foamed molded article subjected to the pretreatment was evaluated in the same manner as in the aforementioned <Antibacterial Property Evaluation (No Pretreatment)>, thereby evaluating the antibacterial property of the foamed molded article after immersion in warm water, in other words, the water resistance of the antibacterial property.

[0244] The bacterial count calculated for the foam molded article of the evaluation object was divided by the bacterial count calculated for the foam molded article of the control, and the antibacterial property evaluation (water resistance) was evaluated based on the same criteria as in the above-mentioned <Antibacterial property evaluation (without pretreatment)>, according to the obtained quotient.

[0245] <Antibacterial property evaluation (light resistance)>

[0246] As a pre-treatment, the foaming molded body was irradiated with a xenon arc lamp for 10 hours. The foaming molded body subjected to the pre-treatment was evaluated according to the same procedure as in the aforementioned <Antibacterial Evaluation (No Pre-treatment)>, thereby evaluating the antibacterial property of the foaming molded body after irradiation with a xenon arc lamp, in other words, the light resistance of the antibacterial property.

[0247] The bacterial count calculated for the foam molded article of the evaluation object was divided by the bacterial count calculated for the foam molded article of the control, and the antibacterial property evaluation (water resistance) was evaluated based on the same criteria as in the above-mentioned <Antibacterial property evaluation (without pretreatment)>, according to the obtained quotient.

[0248] <Example 1>

[0249] KANEPEARL (registered trademark) NSG-B (average particle size: 0.90 mm to 0.95 mm, manufactured by Kaneka Co., Ltd.) was used as the foamable resin particle body. KANEPEARL (registered trademark) NSG-B (i) comprises a base resin and a foaming agent, (ii) the base resin is a styrene-based resin containing 100% styrene units, and (iii) 7 parts by weight of butane is contained as a foaming agent in 100 parts by weight of the foamable resin particle body.

[0250] An aqueous solution of N-hydroxyethyl-N-2-hydroxyalkylamine salt (7.69 wt% aqueous solution, EC-4, manufactured by Kitakyu Chemical Co., Ltd., a mixture of the amine salt having 10 carbon atoms and the amine salt having 12 carbon atoms, the content ratio of the amine salt having 10 carbon atoms and the amine salt having 12 carbon atoms being 50:50) as the component (A) was added (applied) to 100 parts by weight of KANEPEARL (registered trademark) NSG-B so that the amount of the N-hydroxyethyl-N-2-hydroxyalkylamine salt relative to 100 parts by weight of the foamable resin particle body was the amount shown in Table 1 (0.003 parts by weight). Then, the mixture was dried with an air flow dryer to obtain a foamable resin particle body (foamable styrene resin particle body) containing the N-hydroxyethyl-N-2-hydroxyalkylamine salt on the surface.

[0251] The total amount of the expandable resin particle body containing N-hydroxyethyl-N-2-hydroxyalkylamine salt on the surface obtained by the above operation (equivalent to 100 parts by weight of KANEPEARL (registered trademark) NSG-B) and the amount of component (B) shown in Table 1 (Cas (castor oil) in the example) are placed in a Nauta mixer and stirred. Then, N-hydroxyethyl-N-2-hydroxyalkylamine (Antista 80S manufactured by TANAKA Chemical Research Institute, 2-hydroxyalkyl carbon number: 14 type) as the component (A) and other external additives (0.15 parts by weight of zinc stearate and 0.05 parts by weight of castor wax) are placed in a Nauta mixer, and the obtained mixture is stirred for 20 minutes. By this operation, expandable resin particles (expandable styrene resin particles) containing components (A) and (B) on the surface are obtained.

[0252] The foamed particles and the foamed molded article were manufactured by the methods described in the aforementioned <Manufacturing of Foamed Particles> and <Manufacturing of Foamed Molded Articles>. The obtained foamable resin particles, foamed particles and foamed molded articles were subjected to the aforementioned various measurements and evaluations. The composition of the foamable resin particles and the various physical properties of the obtained foamable resin particles, foamed particles and foamed molded articles are shown in Table 1.

[0253] [Examples 2 to 5 and Comparative Examples 1 to 6]

[0254] Except that the type and amount of the external additives used were changed to the type and amount described in Tables 1 to 3, respectively, by the same method as in Example 1, foamable resin particles, foamable particles and foamed molded products were obtained. The foamable resin particles, foamable particles and foamed molded products obtained were subjected to the aforementioned various measurements and evaluations. The composition of the foamable resin particles and the physical properties of the foamable resin particles, foamable particles and foamed molded products obtained are shown in Tables 1 to 3. It should be noted that laurylamine as component (A) was added (applied) at the same time as component (B), that is, before N-hydroxyethyl-N-2-hydroxyalkylamine as component (A) and zinc stearate and castor wax as other external additives.

[0255] The (B) component used is as follows.

[0256] · Castor oil (manufactured by Ito Oil Manufacturing Co., Ltd., special type A)

[0257] Polypropylene glycol (PPG) (manufactured by NOF Corporation, D-250 (number average molecular weight 250), D-1000 (number average molecular weight 1000), D-2000 (number average molecular weight 2000), D-4000 (number average molecular weight 4000))

[0258] Polybutylene glycol (PBG) (manufactured by NOF Corporation, PB-2000 (number average molecular weight 2000))

[0259] It should be noted that the number average molecular weights of the polypropylene glycol and polybutylene glycol described above are values ​​described in the data sheets of the products.

[0260] In the examples and comparative examples, N-hydroxyethyl-N-2-hydroxyalkylamine salt and N-hydroxyethyl-N-2-hydroxyalkylamine as the component (A), and zinc stearate and castor wax as other external additives are all solid at room temperature. In the examples and comparative examples, laurylamine as the component (A) and castor oil, polypropylene glycol and polybutylene glycol as the components (B) are all liquid at room temperature.

[0261] [Table 1]

[0262]

[0263] [Table 2]

[0264]

[0265] [Table 3]

[0266]

[0267] Industrial Applicability

[0268] According to one embodiment of the present invention, it is possible to provide foamable resin particles that can provide a foaming molded body with excellent antibacterial properties. Therefore, one embodiment of the present invention can be suitable for use as packaging materials (trays) for food containers, various packaging materials, building civil engineering components, automobile components, insulation materials for piping, roof insulation materials, solar energy system insulation materials, water heater insulation materials, etc.

Claims

1. A foamable resin particle comprising a base resin and a foaming agent, The base resin comprises a styrene resin, The surface of the expandable resin particles contains (A) an amine compound and (B) at least one selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol, and polybutylene glycol. The number average molecular weight of the polypropylene glycol is greater than 800, The number average molecular weight of the polybutylene glycol is 300 or more.

2. The expandable resin particles according to claim 1, wherein With respect to 100 parts by weight of the foamable resin particle body, The content of the component (A) is 0.03 to 0.50 parts by weight. The content of the component (B) is 0.03 to 0.30 parts by weight.

3. The expandable resin particles according to claim 1 or 2, wherein The component (A) includes one or more selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine, salts of N-hydroxyethyl-N-2-hydroxyalkylamine, alkylamine compounds having no hydroxyl group, and alkenylamine compounds having no hydroxyl group.

4. The expandable resin particles according to claim 1 or 2, wherein The component (B) includes one or more selected from the group consisting of castor oil, polypropylene glycol, and polybutylene glycol.

5. The expandable resin particles according to claim 1 or 2, wherein The number average molecular weight of the polypropylene glycol is 4500 or less.

6. The expandable resin particles according to claim 1 or 2, wherein The number average molecular weight of the polybutylene glycol is 5,000 or less.

7. The expandable resin particles according to claim 4, wherein The polypropylene glycol and the polybutylene glycol are liquid at room temperature. 8 . Expanded beads obtained by expanding the expandable resin beads according to claim 1 .

9. A foamed molded product obtained by molding the foamed particles according to claim 8.

10. A method for producing expandable resin particles, comprising: a base resin and a foaming agent; The method comprises a coating step of coating the surface of the expandable resin particle body with (A) an amine compound and (B) at least one selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol and polybutylene glycol, The base resin comprises a styrene resin, The number average molecular weight of the polypropylene glycol is greater than 800, The number average molecular weight of the polybutylene glycol is 300 or more.

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