Foamable resin particle, method for producing the same, foamed particle and foamed molding

Abstract

To provide foamable resin particles that can yield a foamed molding with superior antibacterial properties.SOLUTION: A foamable resin particle comprises a base resin comprising a styrene resin and a foaming agent, with the surface further comprising (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 with a specific molecular weight, and polybutylene glycol with a specific molecular weight.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to expandable resin beads, a method for producing the same, expanded beads, and foamed molded articles. [Background technology]

[0002] Expandable polystyrene-based resin particles are well known as expandable resin particles. Expandable polystyrene-based resin particles are widely used because they can be easily used to obtain molded articles by in-mold foaming and are inexpensive.

[0003] For example, Patent Document 1 proposes expandable styrene-based resin particles, expanded particles, and expanded molded articles having a low electrostatic charge, which contain N-hydroxyethyl-N-2-hydroxyalkylamine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-114987 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the foamed molded articles obtained from the expandable resin particles obtained by the above-mentioned conventional techniques have room for improvement in terms of antibacterial properties.

[0006] One embodiment of the present invention has been made in consideration of the above problems, and an object of the present invention is to provide novel expandable resin particles that can provide a foamed molded article having excellent antibacterial properties. [Means for solving the problem]

[0007] The present inventors conducted extensive research to solve the above problems and have now completed the present invention.

[0008] That is, one embodiment of the present invention includes the following configuration. [1] Expandable resin particles comprising a base resin and a blowing agent, the base resin comprising a styrene-based resin, the expandable resin particles comprising, on a surface thereof, (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, the number average molecular weight of the polypropylene glycol being 800 or more, and the number average molecular weight of the polybutylene glycol being 300 or more. [2] The expandable resin particles according to [1], wherein the content of the (A) component is 0.03 parts by weight to 0.50 parts by weight and the content of the (B) component is 0.03 parts by weight to 0.30 parts by weight, relative to 100 parts by weight of the expandable resin particle body. [3] The expandable resin particles according to [1] or [2], wherein the component (A) includes at least one selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine, a salt of N-hydroxyethyl-N-2-hydroxyalkylamine, an alkylamine compound not having a hydroxyl group, and an alkenylamine compound not having a hydroxyl group. [4] The expandable resin particles according to any one of [1] to [3], wherein the component (B) contains one or more selected from the group consisting of castor oil, polypropylene glycol, and polybutylene glycol. [5] The expandable resin particles according to any one of [1] to [4], wherein the polypropylene glycol has a number average molecular weight of 4,500 or less. [6] The expandable resin particles according to any one of [1] to [5], wherein the polybutylene glycol has a number average molecular weight of 5,000 or less. [7] The expandable resin particles according to [4], wherein the polypropylene glycol and the polybutylene glycol are liquid at room temperature. [8] Expanded particles obtained by expanding the expandable resin particles according to any one of [1] to [7]. [9] A foamed molded article obtained by molding the foamed beads according to [8].

[10] A method for producing expandable resin particles containing a base resin and a blowing agent, comprising a coating step of coating a surface of an expandable resin particle body with (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 base resin contains a styrene-based resin, the polypropylene glycol has a number average molecular weight of 800 or more, and the polybutylene glycol has a number average molecular weight of 300 or more. Effect of the Invention

[0009] According to one embodiment of the present invention, it is possible to provide a novel expandable resin particle that can provide a foamed molded article having excellent antibacterial properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] In this specification, the term "X unit" contained in a polymer, copolymer, or resin means a "structural unit derived from an X monomer." For example, a "styrene unit" means a "structural unit derived from a styrene monomer."

[0012] Unless otherwise specified in this specification, the structural unit is X 1 Units, X 2 Units, ..., and X n A copolymer containing units (n is an integer of 2 or more) is called "X 1 / X 2 / ··· / X n Also called "copolymer". X 1 / X 2 / ··· / X n Unless otherwise specified, the polymerization mode of the copolymer is not particularly limited, and the copolymer may be a random copolymer, an alternating copolymer, a block copolymer, or a graft copolymer.

[0013] 1. Technical Concept of One Embodiment of the Present Invention There are cases where a foam molded article is required to have antibacterial properties. Therefore, the present inventors have conducted extensive research with the objective of (a) providing novel expandable resin particles capable of providing a foam molded article having excellent antibacterial properties.

[0014] Conventionally, N-hydroxyethyl-N-2-hydroxyalkylamine has been known as an external additive for expandable resin particles, as described in Patent Document 1. Patent Document 1 describes a technique in which N-hydroxyethyl-N-2-hydroxyalkylamine is contained in expandable resin particles for the purpose of achieving antistatic performance. Patent Document 1 does not describe anything about antibacterial properties.

[0015] As a result of the inventor's investigations, he has come to the novel finding that when N-hydroxyethyl-N-2-hydroxyalkylamine disclosed in Patent Document 1 is applied to the surface of expandable resin particles, the foamed molded article obtained from the expandable resin particles cannot exhibit antibacterial properties.

[0016] As a result of further intensive research, the present inventors have surprisingly made the new discovery that by applying component (B) (one or more selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycols having a number average molecular weight of a specific value or more, and polybutylene glycols having a number average molecular weight of a specific value or more) to the surfaces of expandable resin particles together with component (A) (amine compound), the foamed molded article obtained from the resulting expandable resin particles has excellent antibacterial properties.

[0017] [2. Expandable resin particles] The expandable resin particles according to one embodiment of the present invention are expandable resin particles comprising a base resin and a blowing agent, the base resin comprising a styrene-based resin, and the expandable resin particles comprising, on the surface thereof, (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, the number average molecular weight of the polypropylene glycol being 800 or more, and the number average molecular weight of the polybutylene glycol being 300 or more.

[0018] The expandable resin particles according to one embodiment of the present invention have the above-mentioned configuration, and therefore have the advantage of being able to provide a foamed molded article with excellent antibacterial properties. Specifically, the expandable resin particles according to one embodiment of the present invention have the above-mentioned configuration, and therefore the expandable resin particles themselves have excellent antibacterial properties, and therefore, expanded particles with excellent antibacterial properties can be provided. The expanded particles with excellent antibacterial properties obtained from the expandable resin particles according to one embodiment of the present invention can provide a foamed molded article with excellent antibacterial properties. The method for evaluating the antibacterial properties will be described in detail in the examples below.

[0019] The expandable resin particles according to one embodiment of the present invention have the above-mentioned configuration, and therefore have the advantage of being able to provide a foamed molded article with excellent antiviral properties. Specifically, the expandable resin particles according to one embodiment of the present invention have the above-mentioned configuration, and therefore the expandable resin particles themselves have excellent antiviral properties, and therefore it is possible to provide expanded particles with excellent antiviral properties. The expanded particles with excellent antiviral properties obtained from the expandable resin particles according to one embodiment of the present invention can provide a foamed molded article with excellent antiviral properties.

[0020] In this specification, the particles obtained by expanding the expandable resin particles may be referred to as "expanded particles", and the molded body obtained by molding the expanded particles may be referred to as "expanded molded body". In this specification, "expandable resin particles, expanded particles, and expanded molded body" may be referred to as "expandable resin particles, etc." In this specification, "expandable resin particles according to one embodiment of the present invention" may be referred to as "expandable resin particles of the present invention", "expanded particles according to one embodiment of the present invention" may be referred to as "expanded particles of the present invention", and "expanded molded body according to one embodiment of the present invention" may be referred to as "expanded molded body of the present invention". In this specification, "(A) amine compound" may be 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" may be referred to as "(B) component".

[0021] In the following description of this specification, (i) resin particles that contain a base resin and a foaming agent but do not contain component (A), component (B), and / or other external additives described below on their surface may be referred to as "expandable resin particle body", and (ii) resin particles that contain a base resin and a foaming agent and further contain component (A), component (B), or other external additives on their surface may be referred to as "expandable resin particles". In this specification, "expandable resin particle body according to one embodiment of the present invention" may be referred to as "the present expandable resin particle body".

[0022] In this specification, the presence of an (A) amine compound on the surface of an expandable resin particle means any one of the following: (i) the entire amount of the (A) amine compound contained in the expandable resin particle forms a layer on the surface of the expandable resin particle body, (ii) the entire amount of the (A) amine compound contained in the expandable resin particle is impregnated into the surface layer portion of the expandable resin particle, or (iii) a portion of the (A) amine compound contained in the expandable resin particle forms a layer on the surface of the expandable resin particle body, and the remaining amount of the (A) amine compound is impregnated into the surface layer portion of the expandable resin particle.

[0023] As an embodiment in which the (A) amine compound is contained on the surface of the expandable resin particles, among the above-mentioned states (i) to (iii), from the viewpoint of being more likely to exhibit antibacterial and antiviral properties, (i) a state in which the entire amount of the (A) amine compound contained in the expandable resin particles forms a layer on the surface of the expandable resin particle body is more preferred.

[0024] In this specification, containing the (B) component on the surface of the expandable resin particles means any one of the following: (i) the entire amount of the (B) component contained in the expandable resin particles forms a layer on the surface of the expandable resin particle body, (ii) the entire amount of the (B) component contained in the expandable resin particles is impregnated into the surface layer portion of the expandable resin particles, or (iii) a portion of the (B) component contained in the expandable resin particles forms a layer on the surface of the expandable resin particle body, and the remaining portion of the (B) component is impregnated into the surface layer portion of the expandable resin particles.

[0025] As an embodiment in which the (B) component is contained on the surface of the expandable resin particles, among the above-mentioned states (i) to (iii), from the viewpoint of being more likely to exhibit antibacterial and antiviral properties, it is more preferable that (i) the entire amount of the (B) component contained in the expandable resin particles forms a layer on the surface of the expandable resin particle body.

[0026] (2-1. Expandable resin particle body) The expandable resin particle body of the present invention contains a base resin and a blowing agent. The expandable resin particle body of the present invention may contain other additives described below, as necessary.

[0027] The expandable resin particles according to one embodiment of the present invention can be said to contain the expandable resin particle body and the amine compound (A) and the component (B) on the surface.

[0028] (2-2. Base resin) In one embodiment of the present invention, the base resin includes a styrene-based resin. In this specification, the term "styrene-based 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 100%. In one embodiment of the present invention, the base resin may (a) be composed only of a styrene-based resin, or (b) contain a resin other than a styrene-based resin as long as the effect of one embodiment of the present invention is not impaired.

[0029] The styrene-based resin may be a homopolymer of styrene consisting of only styrene units. The styrene-based resin may be a copolymer consisting of styrene units and constitutional units derived from a monomer other than styrene. In the copolymer, the constitutional units derived from a monomer other than styrene may be one type or two or more types.

[0030] Examples of the monomer other than styrene include (a) monofunctional monomers such as styrene derivatives, acrylic acid esters, methacrylic acid esters, acrylonitrile, dimethyl fumarate, and ethyl fumarate, and (b) difunctional monomers such as divinylbenzene and alkylene glycol dimethacrylate.

[0031] Examples of the styrene derivatives include α-methylstyrene, paramethylstyrene, t-butylstyrene, and chlorostyrene.

[0032] Examples of the acrylic acid ester include methyl acrylate, ethyl acrylate, butyl acrylate, and cetyl acrylate.

[0033] Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, butyl methacrylate, and cetyl methacrylate.

[0034] (2-3. Foaming Agent) The foaming agent contained in the present expandable resin particles is not particularly limited.

[0035] Specific examples of the blowing agent include volatile blowing agents such as (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 potential of zero, such as difluoroethane and tetrafluoroethane.

[0036] These foaming agents may be used alone or in combination of two or more.

[0037] The content of the foaming agent in the present expandable resin particles is preferably 3 to 10 parts by weight, and more preferably 4 to 8 parts by weight, based on 100 parts by weight of the base resin.

[0038] (2-4. Other Additives) In addition to the base resin and the blowing agent, the expandable resin particle body may further contain other additives as desired, within the scope of not impairing the effect of one embodiment of the present invention. Examples of the other additives include solvents, plasticizers, cell regulators, nucleating agents, flame retardants, flame retardant auxiliaries, heat radiation inhibitors, pigments, dyes, and monomer components.

[0039] The other additives may be added to the expandable resin bead body during the production of the expandable resin bead body, for example. The timing and / or method of adding these other additives to the expandable resin bead body is not particularly limited. When the expandable resin bead body contains other additives, the expandable resin bead may also contain other additives.

[0040] (2-5. Method for producing expandable resin particle body) The method for producing the expandable resin particle body includes a method of preparing (polymerizing) the base resin and then impregnating the obtained base resin with the blowing agent. The method for preparing (polymerizing) the base resin and the method for impregnating the blowing agent can be any known manufacturing method and are not particularly limited. However, when a seed suspension polymerization method is adopted as the method for preparing the base resin, the constituent unit in the resin particle body that becomes the seed (i.e., the constituent unit contained in the seed) is also included as the constituent unit of the base resin of the expandable resin particle body (i.e., the constituent unit of the base resin of the expandable resin particle).

[0041] (2-6.(A) Amine compounds) The expandable resin particles of the present invention contain an amine compound as component (A). By applying component (A) to the surface of the expandable resin particle body, expandable resin particles containing component (A) on the surface of the expandable resin particle can be obtained.

[0042] The (A) component applied to the expandable resin particle body is substantially entirely attached to the expandable resin particle body and is contained in the expandable resin particle. In this specification, among the additives, those contained on the surface of the expandable resin particle, in other words, those applied to the surface of the expandable resin particle body, are referred to as "external additives". In other words, the (A) component acts as an external additive, and the (A) component can also be called an external additive. The "content" of the (A) component in the expandable resin particle can also be called the "application amount" of the (A) component to the expandable resin particle body.

[0043] The present expandable resin particles contain component (A) and thus have excellent antibacterial properties, making it possible to provide expanded particles and foamed molded articles having excellent antibacterial properties. The reason why component (A) causes the antibacterial properties of expandable resin particles and the like is not clear, but it is presumed as follows: component (A) (e.g., alkylamine compounds and alkenylamine compounds) is thought to weaken the intermolecular interactions of the substances that constitute the cell membrane and cell wall of bacteria, destroying the cell membrane and cell wall. That is, component (A) interacts with or binds to the substances that constitute the cell membrane and cell wall of bacteria, thereby inhibiting the binding (intermolecular binding) between the substances that constitute the cell membrane and cell wall of bacteria. However, the present invention is not limited to such a presumption.

[0044] The expandable resin particles may have excellent antiviral properties by including component (A), and may be able to provide expanded particles and foamed molded articles having excellent antiviral properties. The reason why component (A) causes the expandable resin particles and the like to exhibit antiviral properties is not clear, but is presumed to be as follows: component (A) (e.g., alkylamine compounds and alkenylamine compounds) is thought to destroy the outer membrane (capsid) of the virus or denature the proteins that form the capsid, thereby terminating the function of the virus. However, the present invention is not limited to such presumption.

[0045] The (A) amine compound is not particularly limited. Since the expandable resin particles have better antibacterial properties, the (A) amine compound contained in the expandable resin particles preferably contains one or more selected from the group consisting of alkylamine compounds and alkenylamine compounds, and more preferably consists of only one or more selected from the group consisting of alkylamine compounds and alkenylamine compounds. Since the expandable resin particles have even better antibacterial properties, the (A) amine compound contained in the expandable resin particles preferably contains one or more selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine, salts of N-hydroxyethyl-N-2-hydroxyalkylamine, alkylamine compounds not having a hydroxyl group, and alkenylamine compounds not having a hydroxyl group, and more preferably consists of only one or more selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine, salts of N-hydroxyethyl-N-2-hydroxyalkylamine, alkylamine compounds not having a hydroxyl group, and alkenylamine compounds not having a hydroxyl group.

[0046] In this specification, "N-hydroxyethyl-N-2-hydroxyalkylamine salt" may be referred to as "N-hydroxyethyl-N-2-hydroxyalkylamine salt". In this specification, "alkylamine compound having no hydroxyl group" may be referred to as "alkylamine compound X", and "alkenylamine compound having no hydroxyl group" may be referred to as "alkenylamine compound X".

[0047] (N-hydroxyethyl-N-2-hydroxyalkylamine and salts of N-hydroxyethyl-N-2-hydroxyalkylamine) The N-hydroxyethyl-N-2-hydroxyalkylamine is not particularly limited, but more preferably, N-hydroxyethyl-N-2-hydroxyalkylamine having 10 to 18 carbon atoms in the 2-hydroxyalkyl group, one amino group, and two hydroxyl groups in the molecule. In this specification, the term "amino group" includes an amino group in which a substituent is bonded to the N of the amino group. When the 2-hydroxyalkyl group has 10 or more carbon atoms, the N-hydroxyethyl-N-2-hydroxyalkylamine does not penetrate into the expandable resin particle body, but forms a layer on the surface of the expandable resin particle body, or even if it is impregnated into the expandable resin particle body, the region of impregnation tends to be limited to the surface layer of the expandable resin particle body. Therefore, the proportion of N-hydroxyethyl-N-2-hydroxyalkylamine that forms a layer on the surface of the expandable resin particle body is high, which is preferable because it exhibits excellent antibacterial and antiviral properties.

[0048] In addition, when the carbon number of the 2-hydroxyalkyl group is 18 or less, the melting point of the N-hydroxyethyl-N-2-hydroxyalkylamine is not too high, so that it is easily melted when heated during molding. Therefore, the risk of the amine remaining undissolved causing deterioration in the fusion of the foamed molded body is reduced, so that a foamed molded body with good fusion properties can be obtained. The N-hydroxyethyl-N-2-hydroxyalkylamine may be a mixture of at least two kinds of N-hydroxyethyl-N-2-hydroxyalkylamines having 2-hydroxyalkyl groups with carbon numbers selected from 10 to 18. In terms of good fusion properties and processability due to the reduced risk of deterioration in the fusion of the foamed molded body, and excellent antibacterial and antiviral properties, the carbon number of the 2-hydroxyalkyl group of the N-hydroxyethyl-N-2-hydroxyalkylamine is more preferably 12 to 16, and even more preferably 14. Alternatively, from the viewpoint of the antibacterial and antiviral properties of the foamed molded article after light irradiation, the N-hydroxyethyl-N-2-hydroxyalkylamine may have a 2-hydroxyalkyl group having preferably 10 to 16 carbon atoms, more preferably 10 to 13 carbon atoms, and even more preferably 10 to 12 carbon atoms.

[0049] (Salt of N-hydroxyethyl-N-2-hydroxyalkylamine) The N-hydroxyethyl-N-2-hydroxyalkylamine salt is not particularly limited as long as it is a salt of N-hydroxyethyl-N-2-hydroxyalkylamine, but more preferably, it is a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having 8 to 14 carbon atoms in the 2-hydroxyalkyl group, one amino group, and two hydroxyl groups in the molecule. The N-hydroxyethyl-N-2-hydroxyalkylamine salt may be a mixture of at least two types of N-hydroxyethyl-N-2-hydroxyalkylamine salts having 8 to 14 carbon atoms in the 2-hydroxyalkyl group. When the 2-hydroxyalkyl group has 8 or more carbon atoms, the N-hydroxyethyl-N-2-hydroxyalkylamine salt is more hydrophobic and less soluble in water. Therefore, the salt is less likely to be washed away by steam during foaming and molding, and the salt is more likely to remain in the foamed molded product. This improves (easier to manifest) the antibacterial effect of the foamed particles or molded product. When the carbon number of the 2-hydroxyalkyl group is 14 or less, N-hydroxyethyl-N-2-hydroxyalkylamine salt does not precipitate when dissolved in water, and can be uniformly applied to the surface of the expandable resin particle body, thereby reducing the variation in antibacterial and antiviral properties between expandable resin particles and between expanded particles. The N-hydroxyethyl-N-2-hydroxyalkylamine salt has a lower limit of the number of carbon atoms in the 2-hydroxyalkyl group of more preferably 9 or more, and even more preferably 10 or more, and an upper limit of the number of carbon atoms in the 2-hydroxyalkyl group of more preferably 13 or less, and even more preferably 12 or less.

[0050] The N-hydroxyethyl-N-2-hydroxyalkylamine salt more preferably contains an N-hydroxyethyl-N-2-hydroxyalkylamine salt in which the 2-hydroxyalkyl group has 10 carbon atoms and an N-hydroxyethyl-N-2-hydroxyalkylamine salt in which the 2-hydroxyalkyl group has 12 carbon atoms, and is particularly preferably a mixture of these. A case will be described in which the N-hydroxyethyl-N-2-hydroxyalkylamine salt contains an N-hydroxyethyl-N-2-hydroxyalkylamine salt in which the 2-hydroxyalkyl group has 10 carbon atoms and an N-hydroxyethyl-N-2-hydroxyalkylamine salt in which the 2-hydroxyalkyl group has 12 carbon atoms, or a mixture of these. In this case, the ratio of the content of N-hydroxyethyl-N-2-hydroxyalkylamine salts having a 2-hydroxyalkyl group with 10 carbon atoms to the content of N-hydroxyethyl-N-2-hydroxyalkylamine salts having a 2-hydroxyalkyl group with 12 carbon atoms in the N-hydroxyethyl-N-2-hydroxyalkylamine salt (content of N-hydroxyethyl-N-2-hydroxyalkylamine salts having a 2-hydroxyalkyl group with 10 carbon atoms: content of N-hydroxyethyl-N-2-hydroxyalkylamine salts having a 2-hydroxyalkyl group with 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, even more preferably 60:40 to 40:60, even more preferably 55:45 to 45:55, particularly preferably 52:48 to 48:52, and most preferably 1:1 (50:50).

[0051] 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 thereof.

[0052] (Alkylamine compounds not having a hydroxyl group and alkenylamine compounds not having a hydroxyl group) The alkylamine compound X is not particularly limited, but since it is possible to obtain expandable resin particles and the like having sufficient antibacterial properties, it preferably contains one or more selected from the group consisting of primary alkylamines, secondary alkylamines, tertiary alkylamines, and polyoxyethylene alkylamines, and more preferably contains one or more selected from the group consisting of laurylamine, cetylamine, stearylamine, dimethyllaurylamine, and polyoxyethylenelaurylamine.

[0053] In the alkylamine compound X, 100% by weight of the alkylamine compound X is preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, even more preferably 90% by weight or more, even more preferably 95% by weight or more, and particularly preferably 100% by weight. In other words, it is particularly preferable that the alkylamine compound X is 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-mentioned range, it has the advantage that it is possible to obtain expandable resin particles and the like having better antibacterial properties.

[0054] The alkenylamine compound X is not particularly limited, but since expandable resin particles and the like having sufficient antibacterial properties can be obtained, it preferably contains one or more selected from the group consisting of primary alkenylamines, secondary alkenylamines, tertiary alkenylamines, and polyoxyethylene alkenylamines, and more preferably contains oleylamine.

[0055] The alkenylamine compound X preferably contains at least one selected from the group consisting of primary alkenylamine, secondary alkenylamine, tertiary alkenylamine and polyoxyethylene alkenylamine in an amount of at least 50% by weight, more preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, even more preferably at least 90% by weight, even more preferably at least 95% by weight, and particularly preferably at least 100% by weight, in 100% by weight of the alkenylamine compound X. In other words, it is particularly preferred that the alkenylamine compound X is composed of only at least one selected from the group consisting of primary alkenylamine, secondary alkenylamine, tertiary alkenylamine and polyoxyethylene alkenylamine. When the amount of one or more selected from the group consisting of primary alkenylamines, secondary alkenylamines, tertiary alkenylamines and polyoxyethylene alkenylamines in the alkenylamine compound X is within the above-mentioned range, it is advantageous in that expandable resin particles and the like having superior antibacterial properties can be obtained.

[0056] The alkylamine compound X is not particularly limited, but preferably has an alkyl group with 12 or more carbon atoms. When the alkyl group of the alkylamine compound X has 12 or more carbon atoms, the alkylamine compound X does not penetrate into the expandable resin particle body, but forms a layer on the surface of the expandable resin particle body, or even if it penetrates into the expandable resin particle body, the region of impregnation tends to be limited to the surface layer of the expandable resin particle body. Therefore, the proportion of the alkylamine compound X that forms a layer on the surface of the expandable resin particle body increases, which has the advantage of being able to exhibit excellent antibacterial and antiviral properties.

[0057] Although the alkylamine compound X is not particularly limited, it is preferable that the number of carbon atoms in the alkyl group is 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 is not too high, so that the alkylamine compound X is easily melted when heated during molding. Therefore, the risk of the undissolved alkylamine compound X impairing the fusion of the foamed molded article is reduced, so that a foamed molded article with good fusion properties can be obtained.

[0058] The alkylamine compound X may be a mixture of at least two kinds of alkylamine compounds X, each having an alkyl group with a carbon number of 12 to 18. The alkylamine compound X has an alkyl group with a carbon number of 14 to 18, more preferably 16 to 18. This configuration has the advantages that (a) expandable resin particles and the like having sufficient antibacterial and antiviral properties can be obtained, (b) expandable resin particles and expanded particles having good fluidity can be obtained, and (c) a foamed molded product having good fusion properties (i.e., a high fusion rate) can be obtained.

[0059] The alkylamine compound X preferably contains 50% by weight or more of the 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, even more preferably 90% by weight or more, even more preferably 95% by weight or more, and particularly preferably 100% by weight. In other words, it is particularly preferable that the alkylamine compound X is composed only of 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-mentioned range, it has the advantages that (a) expandable resin particles having sufficient antibacterial and antiviral properties can be obtained, (b) expandable resin particles and expanded particles having good fluidity can be obtained, and (c) a foamed molded product having good fusion properties (i.e., a high fusion rate) can be obtained.

[0060] The alkenylamine compound X is not particularly limited, but preferably has an alkenyl group with 12 or more carbon atoms. When the alkenyl group of the alkenylamine compound X has 12 or more carbon atoms, the alkenylamine compound X does not penetrate into the expandable resin particle body, but forms a layer on the surface of the expandable resin particle body, or even if it penetrates into the expandable resin particle body, the impregnated area tends to be limited to the surface layer of the expandable resin particle body. Therefore, the proportion of the alkenylamine compound X that forms a layer on the surface of the expandable resin particle body increases, which has the advantage of being able to exhibit excellent antibacterial and antiviral properties.

[0061] Although the alkenylamine compound X is not particularly limited, it is preferable that the carbon number of the alkenyl group is 18 or less. When the carbon number of the alkenyl group of the alkenylamine compound X is 18 or less, the melting point of the alkenylamine compound X is not too high, so that the alkenylamine compound X is easily melted when heated during molding. Therefore, the risk of the undissolved alkenylamine compound X impairing the fusion of the foamed molded article is reduced, so that a foamed molded article with good fusion properties can be obtained.

[0062] The alkenylamine compound X may be a mixture of at least two kinds of alkenylamine compounds X, each having an alkenyl group with a carbon number selected from 12 to 18. The alkenylamine compound X preferably has an alkenyl group with a carbon number of 14 to 18, more preferably 16 to 18. This configuration has the advantages that (a) expandable resin particles and the like having sufficient antibacterial and antiviral properties can be obtained, (b) expandable resin particles and expanded particles having good fluidity can be obtained, and (c) a foamed molded product having good fusion properties (i.e., a high fusion rate) can be obtained.

[0063] The alkenylamine compound X preferably contains 50% by weight or more of the alkenylamine compound X having an alkenyl 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, even more preferably 90% by weight or more, even more preferably 95% by weight or more, and particularly preferably 100% by weight. In other words, it is particularly preferable that the alkenylamine compound X is composed only of the alkenylamine compound X having an alkenyl group with 12 or more carbon atoms. When the amount of the alkenylamine compound X having an alkenyl group with 12 or more carbon atoms is within the above-mentioned range in the alkenylamine compound X, it has the advantages that (a) expandable resin particles having sufficient antibacterial and antiviral properties can be obtained, (b) expandable resin particles and expanded particles having good fluidity can be obtained, and (c) a foamed molded product having good fusion properties (i.e., a high fusion rate) can be obtained.

[0064] Since the expandable resin particles and the like have particularly excellent antibacterial and antiviral properties, the expandable resin particles contain, as the amine compound (A), (a) more preferably, the amine compound contains one or more selected from the group consisting of salts of N-hydroxyethyl-N-2-hydroxyalkylamines in which the 2-hydroxyalkyl group has 10 carbon atoms, salts of N-hydroxyethyl-N-2-hydroxyalkylamines in which the 2-hydroxyalkyl group has 12 carbon atoms, N-hydroxyethyl-N-2-hydroxyalkylamines in which the 2-hydroxyalkyl group has 10 carbon atoms, N-hydroxyethyl-N-2-hydroxyalkylamines in which the 2-hydroxyalkyl group has 12 carbon atoms, N-hydroxyethyl-N-2-hydroxyalkylamines in which the 2-hydroxyalkyl group has 14 carbon atoms, N-hydroxyethyl-N-2-hydroxyalkylamines in which the 2-hydroxyalkyl group has 16 carbon atoms, N-hydroxyethyl-N-2-hydroxyalkylamines in which the 2-hydroxyalkyl group has 17 carbon atoms, N-hydroxyethyl-N-2-hydroxyalkylamines in which the 2-hydroxyalkyl group has 18 carbon atoms, laurylamine, cetylamine, stearylamine, oleylamine, dimethyllaurylamine, and polyoxyethylenelaurylamine, (b)(bi) a mixture of a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having a carbon number of 10 in the 2-hydroxyalkyl group and a salt of N-hydroxyethyl-N-2-hydroxyalkylamine having a carbon number of 12 in the 2-hydroxyalkyl group in a weight ratio of 50:50 (e.g., EC-4, manufactured by Kitahiro Chemical Co., Ltd.); (b-ii) a mixture of N-hydroxyethyl-N-2-hydroxyalkylamine having a carbon number of 10 in the 2-hydroxyalkyl group and N-hydroxyethyl-N-2-hydroxyalkylamine having a carbon number of 12 in the 2-hydroxyalkyl group (e.g., Dasper 125B, manufactured by Miyoshi Oil Co., Ltd.); (b-iii) N-hydroxyethyl-N-2-hydroxyalkylamine having a carbon number of 14 in the 2-hydroxyalkyl group. (e.g., Antista 80S, manufactured by Tanaka Chemical Laboratory), (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 in the 2-hydroxyalkyl group (e.g., Antista 80FS, manufactured by Tanaka Chemical Laboratory), (bv) laurylamine, (b-vi) cetylamine, (b-vii) stearylamine, (b-viii) oleylamine, (b-ix) dimethyllaurylamine, and (bx) polyoxyethylenelaurylamine, It is particularly preferred that the amine compound contains one or more members selected from the group consisting of (c) (ci) a mixture of a salt of N-hydroxyethyl-N-2-hydroxyalkylamine in which the 2-hydroxyalkyl group has 10 carbon atoms and a salt of N-hydroxyethyl-N-2-hydroxyalkylamine in which the 2-hydroxyalkyl group has 12 carbon atoms, in a weight ratio of 50:50, (c-ii) N-hydroxyethyl-N-2-hydroxyalkylamine in which the 2-hydroxyalkyl group has 14 carbon atoms, and (c-iii) laurylamine.

[0065] In one embodiment of the present invention, the content of the (A) component is not particularly limited. In this specification, the "content of the (A) component" refers to the total content of all substances contained in the expandable resin particles as the (A) component. For example, when the expandable resin particles contain, as the (A) component, N-hydroxyethyl-N-2-hydroxyalkylamine, a salt of N-hydroxyethyl-N-2-hydroxyalkylamine, an alkylamine compound not having a hydroxyl group, and an alkenylamine compound not having a hydroxyl group, the "content of the (A) component" in the expandable resin particles refers to the "total amount of the content of the N-hydroxyethyl-N-2-hydroxyalkylamine, the content of the salt of N-hydroxyethyl-N-2-hydroxyalkylamine, the content of the alkylamine compound not having a hydroxyl group, and the content of the alkenylamine compound not having a hydroxyl group."

[0066] The "content of N-hydroxyethyl-N-2-hydroxyalkylamine" and the "content of N-hydroxyethyl-N-2-hydroxyalkylamine salt" respectively intend the total content of the mixture when the "N-hydroxyethyl-N-2-hydroxyalkylamine" and the "N-hydroxyethyl-N-2-hydroxyalkylamine salt" are mixtures of multiple compounds having different numbers of carbon atoms in the 2-hydroxyalkyl group.

[0067] The "content of alkylamine compound having no hydroxyl group (alkylamine compound X)" refers to the total content of the mixture when alkylamine compound X is a mixture of multiple compounds having alkyl groups with different carbon numbers, and the "content of alkenylamine compound having no hydroxyl group (alkenylamine compound X)" refers to the total content of the mixture when alkenylamine compound X is a mixture of multiple compounds having alkenyl groups with different carbon numbers.

[0068] 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 expandable resin particle body. When the content of component (A) is 0.03 parts by weight or more relative to 100 parts by weight of the expandable resin particle body, the expandable resin particles etc. have the advantage of being more excellent in antibacterial and antiviral properties.

[0069] The expandable resin particles and the expanded particles may be transported by air transport or moved through a pipe, for example. Therefore, the expandable resin particles and the expanded particles may be required to have excellent fluidity. The expanded particles and the expanded molded article may be required to have excellent fusion properties. When the content of component (A) is 0.50 parts by weight or less per 100 parts by weight of the expandable resin particle body, (i) the expandable resin particles and the expanded particles have the advantage of excellent fluidity, and / or (ii) the expanded particles and the expanded molded article have the advantage of excellent fusion properties.

[0070] The case where the expandable resin particles contain N-hydroxyethyl-N-2-hydroxyalkylamine as component (A) will be described. The content of the N-hydroxyethyl-N-2-hydroxyalkylamine is preferably 0.03 parts by weight to 0.50 parts by weight relative to 100 parts by weight of the expandable resin particle body. If the content of the N-hydroxyethyl-N-2-hydroxyalkylamine is 0.03 parts by weight or more relative to 100 parts by weight of the expandable resin particle body, it is preferable because the antibacterial and antiviral properties of the expanded molded product are improved, and if it is 0.50 parts by weight or less, it is preferable because the expanded particles have excellent fluidity. Furthermore, in the course of intensive research, the present inventors have newly found the finding that when the content of the N-hydroxyethyl-N-2-hydroxyalkylamine is 0.50 parts by weight or less, the action of fusing the expanded particles together is improved in the process of molding the expanded molded product from the expanded particles obtained by expanding the expandable resin particles, and the fusing property of the expanded particles constituting the expanded molded product is improved. The content of the N-hydroxyethyl-N-2-hydroxyalkylamine is more preferably 0.04 parts by weight to 0.40 parts by weight, even more preferably 0.05 parts by weight to 0.30 parts by weight, and particularly preferably 0.05 parts by weight to 0.25 parts by weight, relative to 100 parts by weight of the expandable resin particle body.

[0071] The case where the expandable resin particles contain N-hydroxyethyl-N-2-hydroxyalkylamine salt as component (A) will be described. The content of the N-hydroxyethyl-N-2-hydroxyalkylamine salt is preferably 0.0005 to 0.013 parts by weight relative to 100 parts by weight of the expandable resin particle body. If the content of the N-hydroxyethyl-N-2-hydroxyalkylamine salt is 0.0005 parts by weight or more relative to 100 parts by weight of the expandable resin particle body, it is preferable because the antibacterial and antiviral properties of the foamed molded product are improved, and if it is 0.013 parts by weight or less, it is preferable because the foamed particles have excellent fluidity. The lower limit of the content of the N-hydroxyethyl-N-2-hydroxyalkylamine salt is more preferably 0.001 parts by weight or more, even more 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.

[0072] The case where the expandable resin particles contain one or more selected from the group consisting of alkylamine compound X and alkenylamine compound X as component (A) will be described. The total content of alkylamine compound X and alkenylamine compound X in the expandable resin particles is preferably 0.03 to 0.50 parts by weight relative to 100 parts by weight of the expandable resin particle body. When the total content of alkylamine compound X and alkenylamine compound X is 0.03 parts by weight or more relative to 100 parts by weight of the expandable resin particle body, the antibacterial properties of the obtained expandable resin particles and the like are improved, which is preferable. Many of the compounds included in the alkylamine compound X and alkenylamine compound X are liquid at room temperature (for example, 20°C). For example, laurylamine, oleylamine, dimethyllaurylamine, and polyoxyethylenelaurylamine are liquid at room temperature. The smaller the content (application amount) of the compound that is liquid at room temperature, the more excellent the flowability of the expandable resin particles tends to be. Therefore, 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 expandable resin bead body, the expandable resin bead and the expanded beads obtained from the expandable resin bead have an advantage of being excellent in fluidity.

[0073] Furthermore, in the course of intensive research, the present inventors have newly discovered the finding that 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 expandable resin bead main body, the effect of fusing the expanded beads together is improved in the process of molding a foamed molded article from the expanded beads obtained by expanding the expandable resin beads, and the fusibility of the expanded beads constituting the foamed molded article is improved.

[0074] From the viewpoint of the antibacterial properties of the resulting expandable 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 even more preferably 0.05 parts by weight or more, relative to 100 parts by weight of the expandable resin particle body. Also, from the viewpoints of (a) the fluidity of the expandable resin particles and the expanded particles, and (b) the fusion property of the foamed molded product, 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, even more 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 expandable resin particle body.

[0075] (2-7.(B) component) The expandable resin particles contain, as component (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. By applying component (B) to the surface of the expandable resin particle body, expandable resin particles containing component (B) on the surface of the expandable resin particle can be obtained.

[0076] Substantially the entire amount of component (B) applied to the expandable resin particle body adheres to the expandable resin particle body and is contained in the expandable resin particle. That is, component (B) acts as an external additive, and component (B) can also be considered as an external additive. The "content" of component (B) in the expandable resin particle can also be considered as the "application amount" of component (B) to the expandable resin particle body.

[0077] In the course of intensive research, the present inventors have independently and surprisingly discovered a novel finding that when expandable resin particles contain component (B) in addition to component (A), the expandable resin particles etc. have even superior antibacterial and antiviral properties.

[0078] In addition, the present inventor independently found the following novel findings in the course of intensive research: Even when the expandable resin particles contain only the (A) component (for example, only N-hydroxyethyl-N-2-hydroxyalkylamine, only alkylamine compound X, or only alkenylamine compound X) without containing the (B) component, the expandable resin particles can exhibit antibacterial and / or antiviral properties. However, compared with the case where the expandable resin particles contain only the (A) component, when the expandable resin particles contain both the (A) component and the (B) component, the expandable resin particles can exhibit the same level of antibacterial and / or antiviral properties even when the content of the (A) component is much lower. The lower the content of the (A) component, the more advantageous (i) the expandable resin particles and the expanded particles have excellent fluidity, and / or (ii) the expanded particles and the expanded molded article have excellent fusion properties. In other words, compared with a case where the expandable resin particles contain only the (A) component, a case where the expandable resin particles contain both the (A) component and the (B) component has excellent antibacterial properties and / or excellent antiviral properties, while having the advantages of (i) the expandable resin particles and the expanded particles having excellent fluidity, and / or (ii) the expanded particles and the foamed molded article having excellent fusion properties.

[0079] The reason why the (B) component exerts antibacterial properties on the expandable resin particles and the like is not clear, but it is presumed as follows: the use of the (B) component mainly strengthens the adhesion of the (A) component (adhesion between the expandable resin particle body and the (A) component) and suppresses the peeling of the (A) component from the expandable resin particles during the (pre)expansion process and molding process. This increases the amount of the (A) component remaining on the surface of the expanded particles and / or the foamed molded article to exert antibacterial properties, which is believed to result in the exertion of antibacterial and antiviral properties. However, the present invention is not limited to such a presumption.

[0080] The ricinoleic acid derivative is not particularly limited, and examples thereof include organic compounds such as triglycerides, amides, and esters, whose fatty acid composition is mainly composed of ricinoleic acid. Castor oil is a triglyceride, and its fatty acid composition is about 90% ricinoleic acid. Therefore, castor oil is also included in the ricinoleic acid derivatives.

[0081] Ricinoleic acid is an ω-9 fatty acid having 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 9th position from the methyl end of the fatty acid (also called the "ω end")) and a hydroxyl group at the 7th carbon from the methyl end of the fatty acid. A saturated fatty acid having a hydroxyl group at the 7th carbon from the methyl end of the fatty acid and having 18 carbon atoms, like ricinoleic acid, but without a carbon-carbon double bond is 12-hydroxystearic acid, which is completely different from ricinoleic acid. In this specification, "ricinoleic acid derivative" refers to a substance having at least a carbon-carbon double bond. "Hardened castor oil" is a substance obtained by hydrogenating castor oil, but its structure is a triglyceride whose fatty acid composition is mainly composed of 12-hydroxystearic acid. Therefore, "hardened castor oil" is not included in the ricinoleic acid derivatives.

[0082] Furthermore, the inventors have found through their investigations that when castor oil is used together with component (A), expandable resin particles and the like having excellent antibacterial properties are obtained, whereas when hardened castor oil is used together with component (A), expandable resin particles having excellent antibacterial properties are not obtained.

[0083] 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 9th position from the methyl group end (also called the "ω end") of the fatty acid). A saturated fatty acid having 18 carbon atoms like oleic acid but no carbon-carbon double bond is hydroxystearic acid, which is completely different from oleic acid. In this specification, "oleic acid derivative" refers to a substance having at least a carbon-carbon double bond.

[0084] The oleic acid derivative is not particularly limited, and examples thereof include organic compounds such as triglycerides, amides, and esters, in which the main component of the fatty acid composition is oleic acid.

[0085] Polypropylene glycol has a propylene oxide structural unit (-C3H6O-). In this specification, "polypropylene glycol" refers to a compound in which the propylene oxide structural unit (-C3H6O-) is the most abundant mol% among the structural units constituting the compound. For example, a polyalkylene glycol that is a copolymer of ethylene oxide and propylene oxide and in which the propylene oxide structural unit is more abundant in mol% than the ethylene oxide structural unit is considered to be "polypropylene glycol" in this specification.

[0086] In one embodiment of the present invention, the number average molecular weight of the polypropylene glycol is 800 or more. The larger the number average molecular weight of the polypropylene glycol, the lower the solubility in water. Polypropylene glycol with a number average molecular weight of 800 or more is difficult to dissolve in water. Therefore, when the number average molecular weight of the polypropylene glycol contained in the expandable resin particles is 800 or more, even after the process of foaming the expandable resin particles using steam and molding the expanded particles using steam, a lot of polypropylene glycol remains in the expanded particles and the foamed molded body, so that the expanded particles and the foamed molded body have the advantage of being excellent in antibacterial and antiviral properties. The number average molecular weight of the polypropylene glycol is preferably 900 or more, more preferably 1000 or more, even more preferably 1500 or more, and particularly preferably 2000 or more. The number average molecular weight of the polypropylene glycol can be measured by the MALDI ToF-MS method. In addition, when the polypropylene glycol is a commercially available product, the number average molecular weight information may be obtained from the product data sheet.

[0087] The upper limit of the number average molecular weight of polypropylene glycol is not particularly limited, but in order to prevent the viscosity of the external additive from becoming too high and to provide excellent handling properties, the number average molecular weight is preferably 4,500 or less, more preferably 4,250 or less, more preferably 4,000 or less, even more preferably 3,500 or less, and particularly preferably 3,000 or less.

[0088] Polybutylene glycol has a butylene oxide structural unit (-C4H8O-). In this specification, "polybutylene glycol" refers to a compound having the highest molar percentage of butylene oxide structural units (-C4H8O-) among the structural units constituting the compound. For example, in the case of a polyalkylene glycol that is a copolymer of ethylene oxide, propylene oxide, and butylene oxide, (i) the polyalkylene glycol having the highest molar percentage of propylene oxide structural units is regarded as "polypropylene glycol" in this specification, and (ii) the polyalkylene glycol having the highest molar percentage of butylene oxide structural units is regarded as "polybutylene glycol" in this specification.

[0089] 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 300 or more is difficult to dissolve in water. Therefore, when the number average molecular weight of polybutylene glycol contained in the expandable resin particles is 300 or more, even after the process of foaming the expandable resin particles using steam and molding the expanded particles using steam, a lot of polybutylene glycol remains in the expanded particles and the foamed molded body, so that the expanded particles and the foamed molded body have the advantage of being excellent in antibacterial and antiviral properties. The number average molecular weight of polybutylene glycol is preferably 400 or more, more preferably 500 or more, more preferably 600 or more, more preferably 700 or more, even more preferably 1000 or more, even more preferably 1500 or more, and particularly preferably 2000 or more. The number average molecular weight of polybutylene glycol can be measured by the MALDI ToF-MS method. Also, when the polybutylene glycol is a commercially available product, the number average molecular weight information may be obtained from the product data sheet.

[0090] The upper limit of the number average molecular weight of polybutylene glycol is not particularly limited, but since the viscosity of the external additive does not become too high and handling is excellent, it is preferably 5000 or less, more preferably 4500 or less, more preferably 4000 or less, even more preferably 3500 or less, and particularly preferably 3000 or less.

[0091] Since the expandable resin particles etc. have superior antibacterial and antiviral properties, it is further preferable that the expandable resin particles contain one or more selected from the group consisting of castor oil, polypropylene glycol and polybutylene glycol as component (B).

[0092] In one embodiment of the present invention, the content of the (B) component is not particularly limited. In this specification, the "content of the (B) component" refers to the total content of all substances contained in the expandable resin particles as the (B) component. For example, when the expandable resin particles contain castor oil, polypropylene glycol, and polybutylene glycol as the (B) component, the "content of the (B) component" in the expandable resin particles refers to the "total amount of the castor oil content, the polypropylene glycol content, and the polybutylene glycol content."

[0093] The content of the (B) component 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, even more preferably 0.10 to 0.20 parts by weight, and particularly preferably 0.12 to 0.18 parts by weight, relative to 100 parts by weight of the expandable resin particle body. When the content of the (B) component is 0.03 parts by weight or more relative to 100 parts by weight of the expandable resin particle body, the expandable resin particle or the like has the advantage of being more excellent in antibacterial and antiviral properties. Many of the compounds contained in the (B) component 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 component (B) is 0.30 parts by weight or less per 100 parts by weight of the expandable resin bead main body, there is an advantage that the expandable resin bead and the expanded bead have excellent fluidity.

[0094] (2-8. Other external additives) In addition to the (A) and (B) components, the expandable resin particles may further contain known external additives (hereinafter also referred to as "other external additives") such as antiblocking agents (e.g., metal salts of higher fatty acids such as zinc stearate and magnesium stearate), antistatic agents, water repellents, and fusion promoters on the surface of the expandable resin particles, to the extent that the effects of one embodiment of the present invention are not impaired. For example, fusion promoters include castor wax (hydroxystearic acid triglyceride), triesters, diesters, monoesters of higher fatty acids such as sorbitan stearate ester, and sucrose esters, which are solid at room temperature. In addition, zinc stearate and magnesium stearate are solid at room temperature.

[0095] The timing of adding (using) these other external additives is not particularly limited. When the other external additives are solid at room temperature, it is preferable to apply the component (A) and the component (B) that are liquid at room temperature and the component (A) and the component (B) that are applied in the form of an aqueous solution to the expandable resin particle body, and then dry them as necessary, and then add the other external additives. The component (A) and the component (B) that are solid at room temperature and that are applied in the form of a solid may be applied together with the other external additives that are solid at room temperature.

[0096] In the course of intensive research, the present inventors independently found a new finding that 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 expandable resin particles (content of external additive that is solid at room temperature / content of external additive that is liquid at room temperature), the more excellent the fluidity of the expandable resin particles and the expanded particles. Note that "external additives that are solid at room temperature but are added (applied) in the form of an aqueous solution" (e.g., salts of N-hydroxyethyl-N-2-hydroxyalkylamine) are also included in "external additives that are solid at room temperature" because only the solid external additives remain on the surface of the expandable resin particles by drying the expandable resin particles after addition (application). In addition, the external additives that are liquid at room temperature include not only the (A) and (B) components but also other external additives as long as they are liquid at room temperature. In addition, the external additives that are solid at room temperature include not only the (A) and (B) components but also other external additives as long as they are solid at room temperature.

[0097] From the viewpoint of the fluidity of the expandable resin particles and the expanded particles, the ratio of the content of external additives that are solid at room temperature to the content of external additives that are liquid at room temperature in the expandable resin particles (content of external additives that are solid at room temperature / content of external additives that are liquid at room temperature) 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, even more preferably 2.40 or more, and particularly preferably 2.50 or more.

[0098] In the course of intensive research, the present inventors independently found a new finding that the smaller the content of the external additive that is solid at room temperature in the expandable resin particles, the better the fusibility of the expanded particles and the foamed molded article. From the viewpoint of the fusibility of the expanded particles and the foamed molded article, the content of the external additive that is solid at room temperature in the expandable 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, even more preferably 0.630 parts by weight or less, and particularly preferably 0.600 parts by weight or less, relative to 100 parts by weight of the expandable resin particle body.

[0099] 3. Method for producing expandable resin particles A method for producing expandable resin particles according to one embodiment of the present invention is a method for producing expandable resin particles containing a base resin and a blowing agent, and includes a coating step of coating the surface of the expandable resin particle body with (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 base resin contains 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. In this specification, "coating" also includes adding and mixing with the expandable resin particle body to incorporate the agent into the surface of the expandable resin particle.

[0100] In this specification, "a method for producing expandable resin particles according to one embodiment of the present invention" may be referred to as "the present production method".

[0101] Each aspect of the present production method will be described below, but apart from the details described below, the description in the section [2. Expandable resin particles] will be used as appropriate.

[0102] (Coating process) The coating process may be, for example, a method (process) of adding the (A) component, the (B) component, and other external additives as required to the expandable resin particle body, and mixing the resulting mixture. Some of the (A) component, the (B) component, and other external additives as required may be added to the expandable resin particle body, and the resulting mixture may be mixed, and the remaining components may be added to the resulting mixture, and the resulting mixture may be mixed. That is, the order in which the (A) component, the (B) component, and other external additives as required are added to the expandable resin particle body is not particularly limited, and they may be added in any order. In addition, the (A) component, the (B) component, and other external additives may be added in the form of each component itself (for example, in a solid state), or may be added in the form of a solution dissolved in any solvent.

[0103] It is preferable to coat the surface of the expandable resin particle body with the (A) component, the (B) component, and other external additives as necessary as uniformly as possible. Therefore, when mixing the expandable resin particle body with the (A) component, the (B) component, and other external additives used as necessary, it is preferable to use a mixer that can mix these external additives uniformly.

[0104] Examples of mixing equipment include (a) mixers such as a Super Mixer, a Nauta Mixer, a Universal Mixer, a Proshare Mixer, an Apex Mixer, a Henschel Mixer, and a Loedige Mixer; and (b) blenders such as a ribbon blender and a tumbler-type blender.

[0105] The mixing conditions in the mixer, such as the mixing time, may be adjusted taking into consideration (a) the mixing capacity of the mixer, and (b) the type and application amount of external additives, such as fatty acid glycerides, and the like.

[0106] The expandable resin bead body can be obtained by impregnating the base resin obtained by polymerization with a blowing agent, as described above in (2-5. Manufacturing method for expandable resin bead body). The polymerization of the base resin and the impregnation with the blowing agent can be carried out in an aqueous suspension. Therefore, the obtained expandable resin bead body may have water attached to the surface. Before applying the (A) component, the (B) component, and other external additives as necessary to the expandable resin bead body, the expandable resin bead body may be dehydrated or dried.

[0107] In addition, when an external additive in the form of an aqueous solution is added to the expandable resin particle body, the external additive may be added, for example, after the expandable resin particle body is dehydrated or dried, but the external additive may also be added during dehydration.

[0108] Many of the N-hydroxyethyl-N-2-hydroxyalkylamine salts that are component (A) are 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 applying (containing) component (A) as uniformly as possible to the expandable resin particle body, it is preferable to prepare an aqueous solution of the N-hydroxyethyl-N-2-hydroxyalkylamine salt that is solid at room temperature, and then apply the aqueous solution of the N-hydroxyethyl-N-2-hydroxyalkylamine salt to the expandable resin particle body.

[0109] The case where (a) solid state (A), (B) and other external additives used as necessary, and (b) liquid or solution state (A), (B) and other external additives used as necessary are added (applied) to the expandable resin particle body will be described. In this case, from the viewpoint of applying the (A), (B) and other external additives used as necessary to the expandable resin particle body as uniformly as possible and obtaining expandable resin particles having excellent antibacterial, antiviral and flow properties, it is preferable to (1) add (apply) the (A), (B) and other external additives used as necessary in the liquid or solution state to the expandable resin particle body, and then (2) add (apply) the (A), (B) and other external additives used as necessary in the solid state to the expandable resin particle body (expandable resin particle) obtained. The following describes the case where (a) component (A), component (B), and other external additives used as needed, which are in a solid state, (b) component (A), component (B), and other external additives used as needed, which are in a liquid state, and (c) component (A), component (B), and other external additives used as needed, which are in a solution state, are added (applied) to the expandable resin particle body. In this case, from the viewpoint of applying the components (A), (B), and other external additives used as necessary as uniformly as possible to the expandable resin particle body and obtaining expandable resin particles, etc., that have excellent antibacterial, antiviral, and fluidity properties, it is preferable to (1) add (apply) the components (A), (B), and other external additives used as necessary in solution to the expandable resin particle body, (2) dry the optionally obtained expandable resin particle body (expandable resin particles), (3) then add (apply) the components (A), (B), and other external additives used as necessary in liquid state to the expandable resin particle body, and (4) finally add (apply) the components (A), (B), and other external additives used as necessary in solid state to the obtained expandable resin particle body (expandable resin particles).

[0110] In the present manufacturing method, the coating step is preferably a step of carrying out the following steps (1) to (4) in this order (however, step (2) is an optional step): (1) An aqueous solution of N-hydroxyethyl-N-2-hydroxyalkylamine salt (preferably a 50:50 mixture by weight of 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) which is component (A) is applied to the surface of the expandable resin particle body, (2) Optionally, the expandable resin particle bodies are dried. (3) applying a component (A) that is liquid at room temperature (preferably, one or more selected from the group consisting of laurylamine, oleylamine, dimethyllaurylamine, and polyoxyethylenelaurylamine) and a component (B) that is liquid at room temperature (preferably, one or more selected from the group consisting of castor oil, polypropylene glycol, and polybutylene glycol); (4) Component (A) which is solid at room temperature (preferably, one or more selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine (preferably, one or more selected from the group consisting of 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), cetylamine, 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) are applied.

[0111] [3. Foam particles] The expanded beads according to one embodiment of the present invention are obtained by expanding the expandable resin beads described in the above section [2. Expandable resin beads].

[0112] The present expanded beads have the advantage of being excellent in antibacterial properties since the present expandable resin beads have the above-mentioned configuration. In addition, the present expanded beads have the advantage of being able to provide an expanded molded article having excellent antibacterial properties since the present expanded beads have the above-mentioned configuration. The present expanded beads preferably further have excellent antiviral properties. The expanded beads having excellent antiviral properties can be obtained by expanding expandable resin beads having excellent antiviral properties. The expanded beads having excellent antiviral properties can provide an expanded molded article having excellent antiviral properties. The present expanded beads preferably further have excellent fluidity. The expanded beads having excellent fluidity can be obtained by expanding expandable resin beads having excellent fluidity. The present expanded beads preferably further have excellent fusion properties. The expanded beads having excellent fusion properties can be obtained by expanding expandable resin beads having excellent fusion properties. The expanded beads having excellent fusion properties can provide an expanded molded article having excellent fusion properties.

[0113] Here, when obtaining a foamed molded article from expandable resin particles, the expandable resin particles may first be expanded to obtain expanded particles, and then the expanded particles may be molded to obtain a foamed molded article. Therefore, in the process of obtaining a foamed molded article from expandable resin particles, the expansion of the expandable resin particles may be referred to as "pre-expanding" or "primary expanding", and the obtained expanded particles may be referred to as "pre-expanded particles" or "primary expanded particles".

[0114] The method for expanding the expandable resin particles can be a conventional method, for example, using a cylindrical pre-expansion device and heating the expandable resin particles with a heating medium such as steam to expand them. The device used for expanding the expandable resin particles and the expansion conditions may be appropriately set depending on the composition of the expandable resin particle body and / or the desired expansion ratio, and are not particularly limited.

[0115] The expansion ratio of the present expanded beads is not particularly limited, and is 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 of the expanded beads is (a) 5 times or more, the expanded beads have an advantage of being able to provide a lightweight expanded molded article, and when the expansion ratio is (b) 80 times or less, the expanded beads have an advantage of being able to provide an expanded molded article having excellent strength. In addition, when the expansion ratio is 80 times or less, the concentration of the antibacterial agent per unit area of ​​the expanded beads does not become too low, which is preferable. The method for measuring the expansion ratio of the expanded beads will be described in detail in the following examples.

[0116] The present invention also includes a method for producing expanded beads. The method for producing expanded beads according to one embodiment of the present invention includes a step of producing expandable resin beads by the above-mentioned method for producing expandable resin beads, and a step of expanding the expandable resin beads.

[0117] [4. Foam Molded Articles] The foamed molded article according to 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 a foamed molded article from the foamed beads, the foamed beads are heated and expanded, which is sometimes referred to as "secondary expansion".

[0118] The present foamed molded article has the advantage of excellent antibacterial properties because the present expandable resin particles and the present expanded particles have the above-mentioned configuration. The present foamed molded article preferably also has excellent antiviral properties. A foamed molded article having excellent antiviral properties can be obtained by molding expanded particles having excellent antiviral properties. The present foamed molded article preferably also has excellent fusion properties. A foamed molded article having excellent fusion properties can be obtained by molding expanded particles having excellent fusion properties.

[0119] The method for molding the expanded beads is not particularly limited, and for example, a normal method such as an in-mold foaming method can be adopted. The in-mold foaming method is a method in which the expanded beads are filled in a mold, a heating medium such as steam is blown into the mold to heat the expanded beads, the expanded beads are expanded, and the expanded beads are fused together to obtain a foamed molded article. The molding of the expanded beads by the in-mold foaming method is sometimes called in-mold molding. The foamed molded article according to one embodiment of the present invention may be one obtained by in-mold molding the present expanded beads described in the above section [3. Expanded beads].

[0120] The apparatus used for molding the expanded beads and the molding conditions may be appropriately set depending on the composition of the expandable resin bead body, the composition of the expanded beads, and / or the desired expansion ratio, and are not particularly limited.

[0121] 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 above-mentioned method for producing foamed beads, and a step of molding the foamed beads.

[0122] [5.Applications] The expandable resin particles, the expanded particles, and the expanded molded body according to one embodiment of the present invention have the advantage of being excellent in antibacterial properties. In addition, one embodiment of the present invention also has the advantage of being able to provide (i) expandable resin particles, the expanded particles, and the expanded molded body having excellent antiviral properties, (ii) expandable resin particles and the expanded particles having excellent flowability, (iii) expandable particles and the expanded molded body having excellent fusion properties, and (iv) an expanded molded body that is lightweight and has excellent shock-absorbing properties and heat insulation properties. Therefore, the expandable resin particles, the expanded particles, and the expanded molded body can be suitably used as packaging materials (trays) for food containers and the like, various packaging materials, building and civil engineering components, automobile components, heat insulation materials for piping, heat insulation materials for roofs, heat insulation materials for solar systems, heat insulation materials for water heaters, and the like. The expandable resin particles, the expanded particles, and the expanded molded body can be suitably used, in particular, as packaging materials (trays) for food containers and the like, various packaging materials, building and civil engineering components, automobile components, and the like. EXAMPLES

[0123] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0124] The manufacturing methods of the expanded beads and the expanded molded articles, and the various measurement and evaluation methods in the examples and comparative examples are as follows. Furthermore, "parts" and "%" are by weight (parts by weight and % by weight) unless otherwise specified.

[0125] <Evaluation of powder peeling from expandable resin particles> The powder peeling of the expandable resin particles was evaluated based on the powder peeling rate of the expandable resin particles. The powder peeling rate of the expandable resin particles was calculated according to the following procedure: <Apparatus and conditions> Equipment: Electric sieve DY-50 Mesh: SUS mesh (opening: 355μm, 42 mesh, φ750mm) Weight of foamed resin particles: 1kg Sifting time: 2 minutes.

[0126] <Method> 1 kg of expandable resin particles was weighed and placed on an electric sieve and sieved for 4 minutes. The powder that fell through the mesh was collected, and if the collected powder contained expandable resin particles, it was removed. The weight of the collected powder was measured, and the obtained value was regarded as the amount of peeling. The peeling rate was calculated using the following formula. Peeling rate [%] = Amount of powder that passed through the sieve / Total amount of external additives added x 100 Here, "total amount of external additives added" means 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 producing 1 kg of expandable resin particles fed to the electric sieve.

[0127] The powder peeling of the expandable resin particles was evaluated from the obtained peeling rate based on the following criteria. Note that the smaller the peeling rate, the less powder peeling, i.e., the better the powder peeling. A rating of "1" or higher was considered to be acceptable. 1: Less than 10% by weight 0:10% by weight or more <Production of expanded beads> The expandable resin particles were put into a pressurized pre-expansion machine (manufactured by Daikai Kogyo Co., Ltd., CH-100). The expandable resin particles were heated using steam as a heating medium at a blowing steam pressure of 0.1 MPa to expand the expandable resin particles to an expansion ratio (bulk ratio) of 60 times, thereby obtaining expanded particles.

[0128] <Expansion ratio (bulk ratio) of expanded beads> The expansion ratio of the expanded beads was measured by the following procedure: (1) Weigh out 10 g of foamed particles and measure them on a 1000 cm 3 into a graduated cylinder; (2) The volume of 10 g of foam particles was measured from the graduations on the measuring cylinder; (3) The expansion ratio of the expanded beads was calculated using the following formula: Expansion ratio (cm 3 / g): Volume of foam particles (cm 3 ) / 10g.

[0129] <Evaluation of fluidity of expandable resin particles> The fluidity of the expandable resin particles was evaluated using the angle of repose. The angle of repose relating to the fluidity of the expandable resin particles was measured by the following procedure: (1) Prepare a box (rectangular or cubic) with a dam on one side and an open top; (2) The expandable resin particles obtained in each Example or Comparative Example were placed in a box so that the upper surface of the box was fully leveled; (3) The weir was removed, and the expandable resin particles were allowed to spill naturally. Then, the angle between the slope formed by the expandable resin particles remaining in the box and the bottom surface (horizontal surface) of the box was measured, and this angle was defined as the angle of repose (°).

[0130] The fluidity of the expandable resin particles was evaluated from the angle of repose obtained based on the following criteria. Note that the smaller the angle of repose, the better the fluidity. A score of "1" or more was considered to be acceptable. 2: Less than 30° 1: More than 30°, less than 32° More than 0:32°.

[0131] <Evaluation of fluidity of expanded particles> The fluidity of the expanded beads was evaluated using the angle of repose. The expanded beads after production were left at room temperature for 6 hours, and within 30 minutes, they were used to measure the angle of repose. The angle of repose, which relates to the fluidity of the expanded beads, was measured by the following procedure: (1) Prepare a box (rectangular or cubic) with a dam on one side and an open top; (2) The expanded beads obtained in each Example or Comparative Example were placed in a box so that the upper surface of the box was fully leveled; (3) The weir was removed, and the expanded particles were allowed to spill naturally. The angle between the slope formed by the expanded particles remaining in the box and the bottom surface (horizontal surface) of the box was measured, and this angle was defined as the angle of repose (°).

[0132] The fluidity of the expanded beads was evaluated from the angle of repose obtained based on the following criteria. The smaller the angle of repose, the better the fluidity. A score of "1" or more was considered to be acceptable. It is less than 1:32°. Greater than 0:32°.

[0133] <Production of foamed molded products> The foamed beads after production were left at room temperature for 24 hours and then used to produce a foamed molded article. The foamed molded article was produced using a mold measuring 450 mm in length, 300 mm in width, and 25 mm in depth and a molding machine (KR-57, manufactured by Daisen Co., Ltd.) according to the following procedure: (1) The foamed particles produced by the above-mentioned method were filled into a mold; (2) In-mold foam molding was performed using steam as the heating medium, with the steam injection time of 22 seconds and the steam pressure of 0.08 MPa (gauge pressure); (3) The mold was water-cooled for 5 seconds, and then vacuum-cooled for 100 seconds; (4) The molded product was removed from the mold to obtain a foamed molded product.

[0134] <Evaluation of adhesion> The fusion property of the foam molded product was evaluated based on the fusion rate of the foam molded product. The fusion rate of the foam molded product was calculated according to the following procedure: (1) The foamed molded product broke; (2) The fracture surfaces were observed, and the number of foamed beads in which the foamed beads were broken, not the interfaces of the foamed beads, was counted relative to the total number of foamed beads present in the observation field; (3) Using the obtained results, the fusion rate was calculated based on the following formula: Fusion rate (%) = ((number of expanded beads where the expanded beads are broken, not at the interface between the expanded beads) / total number of beads present in the observation field) x 100.

[0135] The fusion property of the foam molded article was evaluated from the obtained fusion rate based on the following criteria. Note that a higher fusion rate (a higher number) indicates better fusion property. A rating of "1" or more was considered to be acceptable. 3: Fusion rate is 90% or more 2: Fusion rate is 85% or more but less than 90% 1: Fusion rate is 70% or more but less than 85% 0: Fusion rate is less than 70%.

[0136] <Antibacterial evaluation (without pretreatment)> In accordance with JIS Z2801, the antibacterial properties of the foamed molded products were evaluated by the following procedure: (1) The bacteria in the solution (E. coli JM109) are 10 4 pieces / ml~10 5 A bacterial solution was prepared so that the number of bacteria was 1 / ml. (2) 0.4 ml of the bacterial solution prepared in (1) was dropped onto the foamed molded product (expansion ratio: 60 times) to be evaluated, and a PP (polypropylene) film (4 x 4 cm) that had been sterilized with a UV lamp was attached to the area where the bacterial solution was dropped. After that, the foamed molded product with the PP film attached was placed in a petri dish and the lid was closed; (3) The bacteria dropped onto the foamed molded body was cultured in a covered petri dish at 35°C for 24 hours; (4) After the incubation, the PP film was removed, 10 ml of liquid was dropped, and the bacteria on the foam and film were collected; (5) 0.02 ml of the solution recovered in (4) above was diluted with 0.18 ml of physiological saline; (6) The dilution procedure in (5) was repeated for the obtained diluted solution until the number of colonies on the agar medium after 24 hours of incubation at 35°C in (8) was 50 or less; (7) 0.1 ml of the final dilution obtained in (6) above was applied onto the agar medium and spread thinly; (8) The bacteria in the final dilution spread on the agar medium in (7) above was cultured at 35°C for 24 hours; (9) The number of colonies on the agar medium was counted, and the number of bacteria surviving on the foamed molded article after the culture in (3) above was calculated from the obtained value (number of colonies) and the dilution ratio.

[0137] As a control, a foam molded product produced in the same manner as in Example 1 described below except that the components (A) and (B) were not added (a foam molded product obtained by applying only zinc stearate and castor wax as external additives) was used. The foam molded product was subjected to the same procedures as in (1) to (9), and the number of bacteria surviving on the foam molded product after the cultivation in (3) was calculated.

[0138] The number of bacteria calculated for the foamed molded product to be evaluated was divided by the number of bacteria calculated for the control foamed molded product. The antibacterial properties (without pretreatment) were evaluated from the obtained quotient based on the following criteria. A smaller quotient indicates better antibacterial properties. A value of "1" or higher was considered to be acceptable. 3: Quotient is 1 / 10000 or less 2: The quotient is greater than 1 / 10000 and less than or equal to 1 / 1000 1: The quotient is greater than 1 / 1000 and less than or equal to 1 / 100 0: The quotient is greater than 1 / 100.

[0139] <Antibacterial evaluation (water resistance)> As a pretreatment, the foam molded article was immersed in hot water at 50°C for 18 hours and then dried. The pretreated foam molded article was evaluated in the same manner as in the above-mentioned <Antibacterial property evaluation (without pretreatment)> to evaluate the antibacterial property of the foam molded article after immersion in hot water, in other words, the water resistance in terms of antibacterial property.

[0140] The number of bacteria calculated for the foamed molded product to be evaluated was divided by the number of bacteria calculated for the control foamed molded product. The quotient was used to evaluate the antibacterial property (water resistance) based on the same criteria as in the above-mentioned <Antibacterial property evaluation (without pretreatment)>.

[0141] <Antibacterial evaluation (light resistance)> As a pretreatment, the foam molded product was irradiated with a xenon arc lamp for 10 hours. The foam molded product that had been subjected to this pretreatment was evaluated in the same manner as in the above-mentioned <Antibacterial property evaluation (without pretreatment)> to evaluate the antibacterial property of the foam molded product after irradiation with a xenon arc lamp, in other words, the light resistance of the antibacterial property.

[0142] The number of bacteria calculated for the foamed molded product to be evaluated was divided by the number of bacteria calculated for the control foamed molded product. The quotient was used to evaluate the antibacterial property (water resistance) based on the same criteria as in the above-mentioned <Antibacterial property evaluation (without pretreatment)>.

[0143] <Example 1> Kanepearl (registered trademark) NSG-B (average particle size: 0.90 mm to 0.95 mm, manufactured by Kaneka Corporation) was used as the expandable resin particle body. Kanepearl (registered trademark) NSG-B contains a base resin and a foaming agent, the base resin is a styrene-based resin with 100% styrene units, and contains 7 parts by weight of butane as a foaming agent per 100 parts by weight of the expandable resin particle body.

[0144] An aqueous solution of N-hydroxyethyl-N-2-hydroxyalkylamine salt (7.69% by weight aqueous solution, EC-4, manufactured by Kitahiro Chemical Co., Ltd., a mixture of the amine salt having 10 carbon atoms in the 2-hydroxyalkyl group and the amine salt having 12 carbon atoms in the 2-hydroxyalkyl group, and the content ratio of the amine salt having 10 carbon atoms in the 2-hydroxyalkyl group and the amine salt having 12 carbon atoms in the 2-hydroxyalkyl group is 50:50) was added (applied) and mixed to 100 parts by weight of the expandable resin particle body so that the amount of N-hydroxyethyl-N-2-hydroxyalkylamine salt relative to 100 parts by weight of the expandable resin particle body was the amount shown in Table 1 (0.003 parts by weight). Then, by drying with an airflow dryer, an expandable resin particle body (expandable styrene-based resin particle body) containing N-hydroxyethyl-N-2-hydroxyalkylamine salt on the surface was obtained.

[0145] The entire amount of the expandable resin particles 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 Example 1) were added to a Nauta mixer and stirred. Then, N-hydroxyethyl-N-2-hydroxyalkylamine (manufactured by Tanaka Chemical Laboratory, Antista 80S, 2-hydroxyalkyl group carbon number: 14 type) which is component (A) and other external additives (0.15 parts by weight of zinc stearate and 0.05 parts by weight of castor wax) were added, and the resulting mixture was stirred for 20 minutes. By such operation, expandable resin particles (expandable styrene-based resin particles) containing component (A) and component (B) on the surface were obtained.

[0146] Expanded beads and expanded molded articles were produced by the methods described in the above-mentioned <Production of Expanded Beads> and <Production of Expanded Molded Articles>. The obtained expandable resin beads, expanded beads, and expanded molded articles were subjected to the above-mentioned various measurements and evaluations. The composition of the expandable resin beads, and the physical properties of the obtained expandable resin beads, expanded beads, and expanded molded articles are shown in Table 1.

[0147] [Examples 2 to 5 and Comparative Examples 1 to 6] Except for changing the type and amount of the external additive used to the types and amounts shown in Tables 1 to 3, expandable resin particles, expanded particles, and expanded molded products were obtained in the same manner as in Example 1. The obtained expandable resin particles, expanded particles, and expanded molded products were subjected to the various measurements and evaluations described above. The composition of the expandable resin particles, and the physical properties of the obtained expandable resin particles, expanded particles, and expanded molded products are shown in Tables 1 to 3. Note that laurylamine, component (A), was added (applied) at the same timing as component (B), that is, before N-hydroxyethyl-N-2-hydroxyalkylamine, component (A), and zinc stearate and castor wax, which are other external additives.

[0148] The components (B) used are as follows: Castor oil (Special Type A, manufactured by Ito Oil Co., Ltd.) Polypropylene glycol (PPG) (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)) Polybutylene glycol (PBG) (NOF Corporation, PB-2000 (number average molecular weight 2000)) In the examples and comparative examples, the (A) component, N-hydroxyethyl-N-2-hydroxyalkylamine salt and N-hydroxyethyl-N-2-hydroxyalkylamine, as well as the other external additives, zinc stearate and castor wax, are all solid at room temperature. In the examples and comparative examples, the (A) component, laurylamine, as well as the (B) components, castor oil, polypropylene glycol and polybutylene glycol, are all liquid at room temperature.

[0149] [Table 1]

[0150] [Table 2]

[0151] [Table 3] [Industrial Applicability]

[0152] According to one embodiment of the present invention, it is possible to provide expandable resin particles capable of providing a foamed molded article having excellent antibacterial properties. Therefore, one embodiment of the present invention can be suitably used as packaging materials (trays) for food containers and the like, various packaging materials, construction and civil engineering components, automobile components, heat insulation materials for piping, roof insulation materials, heat insulation materials for solar systems, heat insulation materials for water heaters, and the like.

Claims

1. Expandable resin particles comprising a base resin and a blowing agent, The base resin includes a styrene-based resin, the expandable resin particles contain, on a surface thereof, (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; The number average molecular weight of the polypropylene glycol is 800 or more, The expandable resin particles, wherein the polybutylene glycol has a number average molecular weight of 300 or more.

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

3. The expandable resin particles according to claim 1, wherein the component (A) comprises at least one selected from the group consisting of N-hydroxyethyl-N-2-hydroxyalkylamine, a salt of N-hydroxyethyl-N-2-hydroxyalkylamine, an alkylamine compound not having a hydroxyl group, and an alkenylamine compound not having a hydroxyl group.

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

5. The expandable resin particles according to claim 1 , wherein the polypropylene glycol has a number average molecular weight of 4,500 or less.

6. The expandable resin particles according to claim 1 , wherein the polybutylene glycol has a number average molecular weight of 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. 8. Expanded beads obtained by expanding the expandable resin beads according to claim 1.

9. A foamed molded article obtained by molding the foamed beads according to claim 8.

10. A method for producing expandable resin particles comprising a base resin and a blowing agent, comprising: a coating step of coating a surface of an expandable resin particle body with (A) an amine compound and (B) one or more members selected from the group consisting of ricinoleic acid, ricinoleic acid derivatives, oleic acid, oleic acid derivatives, polypropylene glycol, and polybutylene glycol, The base resin includes a styrene-based resin, The number average molecular weight of the polypropylene glycol is 800 or more, The method for producing expandable resin particles, wherein the polybutylene glycol has a number average molecular weight of 300 or more.

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