Resin composition, expandable resin composition, and extruded foam molded product

Abstract

Provided are a resin composition that can enhance the flame retardancy of various thermoplastic resins and impart excellent heat resistance, and a foamable resin composition that is suitable for obtaining extruded foam molded articles that are highly flame retardant and also excellent in heat resistance. [Solution] The resin composition of the present invention contains a thermoplastic resin, a brominated flame retardant, and an organic phosphonic acid. The foamable resin composition of the present invention contains the resin composition and a blowing agent. The foamable resin composition of the present invention can be used to obtain extruded foams with excellent flame retardancy.

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a foamable resin composition, and an extruded foam. [Background technology]

[0002] Foam molded products, typified by styrene-based resin foams, are lightweight and therefore widely used in a variety of fields, including, for example, insulation applications in home appliances and building materials, civil engineering applications in embankment construction, etc. Since many thermoplastic resins, such as styrene-based resins, are composed only of carbon and hydrogen, they have the property of emitting black smoke and burning violently once ignited, and therefore it is necessary to make the resin flame-retardant using a flame retardant depending on the application of the foam molded product.

[0003] Conventionally, hexabromocyclododecane (HBCD) has been used as a flame retardant to make foamed molded articles primarily composed of thermoplastic resins flame retardant, and it is known that the desired flame retardant effect can be obtained with a relatively small amount of use. In recent years, other brominated flame retardants have been adopted in place of HBCD, and for example, brominated flame retardants such as tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether) are often used (see, for example, Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-331964 Summary of the Invention [Problem to be solved by the invention]

[0005] However, while conventional brominated flame retardants can impart flame retardancy to foams of certain resins, the flame retardancy is still insufficient in some cases and the flame retardancy requirements, which have been increasing in recent years, are not always met. In particular, it has been more difficult to make foam molded articles made from recycled thermoplastic resins (e.g., recycled polystyrene or recycled polypropylene) flame-retardant than virgin resins (e.g., resins obtained from petroleum as a raw material).

[0006] The present invention has been made in view of the above, and an object of the present invention is to provide a resin composition that can enhance the flame retardancy of various thermoplastic resins. [Means for solving the problem]

[0007] As a result of extensive research into achieving the above object, the inventors have found that the above object can be achieved by using a thermoplastic resin, a brominated flame retardant, and an organic phosphonic acid, and have thus completed the present invention.

[0008] That is, the present invention includes, for example, the subject matter described in the following sections. Item 1 A resin composition comprising a thermoplastic resin, a brominated flame retardant, and an organic phosphonic acid. Section 2 Item 2. The resin composition according to item 1, wherein the organic phosphonic acid has a 5% weight loss temperature of 150° C. or higher when heated in a nitrogen atmosphere at a heating rate of 10° C. / min. Section 3 Item 3. The resin composition according to item 1 or 2, wherein the organic phosphonic acid is solid at 20°C. Section 4 Item 4. The resin composition according to any one of Items 1 to 3, wherein the organic phosphonic acid is at least one selected from the group consisting of 1-hydroxyethane-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, and ethylenediaminetetramethylenephosphonic acid. Section 5 Item 5. The resin composition according to any one of items 1 to 4, wherein the brominated flame retardant is at least one selected from the group consisting of tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tris(2,3-dibromopropyl)isocyanurate, tris(tribromophenoxy)triazine, and brominated epoxy oligomers. Section 6 6. The resin composition according to any one of items 1 to 5, wherein the organic phosphonic acid is contained in an amount of 0.05 parts by mass or more and 1 part by mass or less relative to 100 parts by mass of the thermoplastic resin. Section 7 7. The resin composition according to any one of items 1 to 6, wherein the organic phosphonic acid is contained in an amount of 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the brominated flame retardant. Section 8 8. The resin composition according to any one of items 1 to 7, which contains at least one metal selected from the group consisting of transition metals, alkali metals, and alkaline earth metals. Section 9 Item 9. The resin composition according to item 8, wherein the metal is contained in the thermoplastic resin. Item 10 Item 10. The resin composition according to any one of items 1 to 9, wherein the thermoplastic resin contains a polystyrene-based resin. Section 11 11. A foamable resin composition comprising the resin composition according to any one of items 1 to 10 and a foaming agent. Item 12 Item 12. An extruded foam containing a foam of the foamable resin composition according to item 11. [Effects of the Invention]

[0009] The resin composition of the present invention can enhance the flame retardancy of various thermoplastic resins.

[0010] Furthermore, the foamable resin composition of the present invention can be used to produce foamed molded articles having excellent flame retardancy, and such foamed molded articles have excellent flame retardancy even when they are derived from recycled thermoplastic resins. DETAILED DESCRIPTION OF THE INVENTION

[0011]

[0023] In the present specification, the terms "contain" and "comprise" include the concepts of "contain," "comprise," "consist essentially of," and "consist only of."

[0012] In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example. In addition, in this specification, numerical values ​​connected with "to" mean a numerical range that includes the numbers before and after "to" as the lower and upper limits.

[0013] 1.Resin composition The resin composition of the present invention contains a thermoplastic resin, a brominated flame retardant, and an organic phosphonic acid. The resin composition of the present invention has high flame retardancy due to the inclusion of a thermoplastic resin, a brominated flame retardant, and an organic phosphonic acid as essential components. More specifically, use of the resin composition of the present invention makes it possible to produce a molded article with excellent flame retardancy.

[0014] In particular, even if the thermoplastic resin contained in the resin composition of the present invention is a recycled thermoplastic resin (hereinafter, sometimes referred to as "recycled resin"), the molded article obtained from such a resin composition has high flame retardancy. Furthermore, the molded article obtained from the resin composition may have excellent heat resistance in addition to flame retardancy.

[0015] Flame retardancy can be evaluated by LOI (Limiting Oxygen Index) or UL-94. For example, in the case of polystyrene resins, the flame retardancy can be evaluated by measuring the LOI (Limiting Oxygen Index), and in the case of polyolefin resins, the flame retardancy can be evaluated by UL-94.

[0016] (thermoplastic resin) The thermoplastic resin is the main component contained in the resin composition of the present invention. The type of thermoplastic resin contained in the resin composition of the present invention is not particularly limited, and a wide range of known thermoplastic resins can be used, for example. The thermoplastic resin may be a so-called virgin resin, i.e., a thermoplastic resin obtained using petroleum as a raw material, or may be a recycled thermoplastic resin (recycled resin).

[0017] Examples of types of virgin resin include polystyrene resins, polyolefin resins, soft polyvinyl chloride resins, hard polyvinyl chloride resins, acrylic resins, acrylonitrile-butadiene-styrene resins, and polycarbonate resins. Among these, polystyrene resins and polyolefin resins are preferred as virgin resins because they are easy to extrude and foam.

[0018] When the virgin resin is a polystyrene-based resin, the type is not particularly limited. For example, polystyrene-based resins used in extrusion foaming can be widely applied to the present invention, including homopolymers of styrene monomers and copolymers of styrene and other monomers. The monomer units constituting the polystyrene-based resin can contain 50% by mass or more of styrene monomer, preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The styrene-based resin may be a homopolymer of polystyrene.

[0019] When the virgin resin is a polyolefin resin, the type thereof is not particularly limited, and for example, polyolefin resins used in extrusion foaming can be widely applied to the present invention. Examples of polyolefin resins include homopolymers of olefin monomers such as ethylene and propylene, copolymers thereof, copolymers containing an olefin monomer as the main component and an olefin monomer and a vinyl monomer polymerizable therewith, and the polyolefin resin may also be a low-density polyethylene resin, a high-density polyethylene resin, or a polypropylene resin.

[0020] The method for producing the virgin resin is not particularly limited, and for example, it can be obtained by a known method, or it can also be obtained from a commercial product.

[0021] On the other hand, examples of types of recycled resins include polystyrene resins, polyolefin resins, flexible polyvinyl chloride resins, rigid polyvinyl chloride resins, acrylic resins, acrylonitrile-butadiene-styrene resins, and polycarbonate resins. Among these, preferred virgin resins are recycled polystyrene resins and recycled polyolefin resins, and recycled polystyrene or recycled polypropylene can be preferably used, because they are easy to extrude and foam, and extruded foam moldings that have high flame retardancy and excellent heat resistance can be easily obtained from them.

[0022] The method for producing recycled resin is not particularly limited, and it can be obtained, for example, by a known method, or it can be obtained from a commercially available product. Recycled resin can be obtained by so-called material recycling, in which used, recovered thermoplastic resin molded articles are pulverized and reused. Recycled resin can also be obtained by chemical recycling (chemical decomposition method) or mechanical recycling. Chemical recycling is a method of resynthesizing thermoplastic resin from raw materials obtained by chemically decomposing used thermoplastic resin molded articles, etc.

[0023] Specifically, foreign matter is removed from a used molded product, which is then crushed and washed, and then pelletized using an extruder to obtain a recycled resin.

[0024] The recycled resin may contain at least one metal selected from the group consisting of transition metals, alkali metals, and alkaline earth metals, as described below. Such metals do not necessarily need to be present as simple elements in the recycled resin, but may be contained as part of a compound.

[0025]

[0023] The thermoplastic resin preferably contains a polystyrene resin or a polypropylene resin, since this makes it easier to obtain extruded foams having excellent flame retardancy. In particular, in the present invention, even if the thermoplastic resin is recycled polystyrene or recycled polypropylene, that is, even if the raw material resin of the extruded foams is recycled polystyrene or recycled polypropylene, extruded foams having excellent flame retardancy can be obtained.

[0026] The thermoplastic resin may further contain other additives as long as the effects of the present invention are not impaired. Examples of additives include light stabilizers, antioxidants, preservatives, surfactants, fillers such as inorganic particles, pigments, colorants, and antifungal agents. One or more of these additives may be contained in the styrene-based resin.

[0027] (Brominated flame retardants) The brominated flame retardant is a component for imparting flame retardancy to the resin composition of the present invention, or to a molded article obtained from the resin composition.

[0028] The type of brominated flame retardant is not particularly limited as long as it is a compound that contains bromine and has the property of being able to impart flame retardancy. For example, known brominated flame retardants contained in extruded foams can be widely applied to the present invention.

[0029] Examples of brominated flame retardants include brominated cycloalkane compounds, brominated aromatic compounds, bromine-containing isocyanurates, and bromine-containing epoxy compounds.

[0030] Examples of brominated aromatic compounds include tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tris(tribromophenoxy)triazine, hexabromobenzene, pentabromotoluene, hexabromobiphenyl, decabromobiphenyl, hexabromocyclodecane, decabromodiphenyl ether, octabromodiphenyl ether, hexabromodiphenyl ether, bis(pentabromophenoxy)ethane, ethylenebis(pentabromophenyl), ethylenebis(tetrabromophthalimide), tetrabromobisphenol A, and the like. brominated epoxy compounds such as diepoxy compounds produced by the reaction of brominated bisphenol A with epichlorohydrin and monoepoxy compounds obtained by the reaction of brominated phenols with epichlorohydrin; halogenated bromine compound polymers such as poly(brominated benzyl acrylate), brominated polyphenylene ether, brominated bisphenol A, condensates of cyanuric chloride and brominated phenol, brominated (polystyrene), poly(brominated styrene), brominated polystyrenes such as crosslinked brominated polystyrene, and crosslinked or non-crosslinked brominated poly(α-methylstyrene).

[0031] An example of an isocyanurate containing bromine is tris(2,3-dibromopropyl)isocyanurate, and an example of an epoxy compound containing bromine is an epoxy oligomer containing bromine. Examples of brominated cycloalkane compounds include hexabromocycloheptane, tetrabromocycloheptane, tetrabromocyclooctane, and hexabromocyclododecane.

[0032] In view of the ease with which an extruded foam having high flame retardancy can be obtained, the brominated flame retardant is preferably at least one selected from the group consisting of tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tris(2,3-dibromopropyl)isocyanurate, tris(tribromophenoxy)triazine, and brominated epoxy oligomers. In particular, in view of the ease with which an extruded foam having high flame retardancy can be obtained, the brominated flame retardant is preferably at least one selected from the group consisting of tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tris(2,3-dibromopropyl)isocyanurate, and brominated epoxy oligomers.

[0033] The brominated flame retardant can be produced by a known method or can be obtained from a commercially available product, etc. One or more brominated flame retardants are contained in the resin composition.

[0034] (organic phosphonic acid) The organic phosphonic acid is an organic compound having a phosphonic acid moiety or a moiety derived from phosphonic acid. In the resin composition of the present invention, the organic phosphonic acid is a component that can function as a chelating agent. Inclusion of the organic phosphonic acid in the resin composition can enhance flame retardancy and may also impart excellent heat resistance. Therefore, inclusion of the organic phosphonic acid in the resin composition can achieve both flame retardancy and heat resistance, which are in a trade-off relationship, in the extrusion foam molded product. Furthermore, inclusion of the organic phosphonic acid in the resin composition of the present invention improves the appearance of the molded product, making it difficult to detect particulate foreign matter (foreign matter derived from the organic phosphonic acid).

[0035] As the organic phosphonic acid, for example, a wide variety of known organic phosphonic acid compounds can be used.

[0036] The organic phosphonic acid preferably has a 5% weight loss temperature of 150°C or higher when heated in a nitrogen atmosphere at a heating rate of 10°C / min. In this case, extruded foam molded articles with high flame retardancy, and in particular extruded foam molded articles with particularly excellent heat resistance, are likely to be obtained. The organic phosphonic acid preferably has a 5% weight loss temperature of 180°C or higher when heated in a nitrogen atmosphere at a heating rate of 10°C / min, more preferably 190°C or higher, even more preferably 200°C or higher, and particularly preferably 215°C or higher.

[0037] The organic phosphonic acid is preferably solid at 20° C. In this case, the resin composition can be easily handled when prepared, and the organic phosphonic acid is easily dispersed uniformly in the molded product, making it easier to obtain an extruded foam having excellent heat resistance.

[0038] The organic phosphonic acid is preferably one or more selected from the group consisting of 1-hydroxyethane-1,1-diphosphonic acid, aminotrimethylenephosphonic acid (also referred to as aminotrismethylenephosphonic acid), 2-phosphonobutane-1,2,4-tricarboxylic acid (also referred to as phosphonobutanetricarboxylic acid), and ethylenediaminetetramethylenephosphonic acid. In this case, flame retardancy can be further improved and heat resistance is also likely to be improved. From the viewpoint of particularly easily improving both flame retardancy and heat resistance, the organic phosphonic acid is particularly preferably ethylenediaminetetramethylenephosphonic acid.

[0039] The organic phosphonic acid can be produced by a known method, or can be obtained from a commercial product.

[0040] The resin composition may contain one or more organic phosphonic acids.

[0041] (Resin composition) The resin composition of the present invention contains the thermoplastic resin, the brominated flame retardant, and the organic phosphonic acid as essential components.

[0042] The organic phosphonic acid is preferably contained in an amount of 0.05 to 1 part by mass per 100 parts by mass of the thermoplastic resin, which makes it easier to obtain an extruded foam having excellent flame retardancy, and also improves the appearance of the foam, making it difficult to find particulate foreign matter in the foam.

[0043] The content of the organic phosphonic acid is more preferably 0.08 parts by mass or more, even more preferably 0.1 parts by mass or more, and more preferably 0.8 parts by mass or less, even more preferably 0.7 parts by mass or less, and particularly preferably 0.6 parts by mass or less, relative to 100 parts by mass of the thermoplastic resin.

[0044] The organic phosphonic acid is preferably contained in an amount of 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the brominated flame retardant, which makes it easier to obtain an extruded foam having excellent flame retardancy, and also improves the appearance of the foam, making it difficult to detect particulate foreign matter, for example.

[0045] The content of the organic phosphonic acid may be 1.5 parts by mass or more relative to 100 parts by mass of the brominated flame retardant, and is more preferably 3 parts by mass or more in terms of facilitating improvement in heat resistance, even more preferably 5 parts by mass or more, and particularly preferably 6 parts by mass or more, and is more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, and particularly preferably 60 parts by mass or less.

[0046] The brominated flame retardant may be contained in an amount of 0.1 to 50 parts by mass, and preferably 0.1 to 10 parts by mass, per 100 parts by mass of the thermoplastic resin, which makes it easier to obtain extruded foams with excellent flame retardancy.

[0047] The content of the brominated flame retardant is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, and particularly preferably 1 part by mass or more, per 100 parts by mass of the thermoplastic resin. It is also more preferably 8 parts by mass or less, more preferably 7 parts by mass or less, and particularly preferably 5 parts by mass or less. From the viewpoint of easily achieving both flame retardancy and heat resistance, the content of the brominated flame retardant is preferably 4 parts by mass or less, more preferably 3 parts by mass or less, and particularly preferably 2 parts by mass or less, per 100 parts by mass of the thermoplastic resin. When the thermoplastic resin is a recycled polystyrene resin, these ranges can be preferably used as the content of the brominated flame retardant. However, when the brominated flame retardant is a combination of tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether) and tetrabromobisphenol A-bis(2,3-dibromopropyl ether), the brominated flame retardant may be contained in an amount of 2 parts by mass or more, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of the thermoplastic resin.

[0048] Among the brominated flame retardants, the content of tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether) is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, and particularly preferably 1 part by mass or more, relative to 100 parts by mass of the thermoplastic resin, and may be 10 parts by mass or less, preferably 9 parts by mass or less, more preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and particularly preferably 1.5 parts by mass or less. When the thermoplastic resin is a recycled polystyrene resin, these ranges can be preferably adopted as the content of the brominated flame retardant.

[0049] However, when the thermoplastic resin is a polyolefin resin such as a recycled polyolefin resin, the bromine-based flame retardant may be contained in an amount of, for example, 25 parts by mass or more per 100 parts by mass of the resin. However, in terms of being more likely to improve heat resistance, 20 parts by mass or less is preferred, 15 parts by mass or less is more preferred, 10 parts by mass or less is even more preferred, and 3 parts by mass or more is preferred, and 5 parts by mass or more is more preferred.

[0050] The resin composition of the present invention may contain other components as long as it contains the thermoplastic resin, the brominated flame retardant, and the organic phosphonic acid as essential components. Furthermore, since the resin composition of the present invention can be used to prepare the foamable resin composition described below, the resin composition of the present invention may contain components that can be contained in the foamable resin composition.

[0051] The resin composition of the present invention may contain a flame retardant auxiliary, which makes it easier to obtain extruded foams with particularly excellent flame retardancy.

[0052] The flame retardant aid may be any of a wide variety of known flame retardant aids that can be used in foamed molded articles. Examples of the flame retardant aid include cumene peroxide, cumene hydroperoxide, di-t-butyl peroxide, di-t-hexyl peroxide, 2,3-diphenyl-2,3-dimethylbutane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, dicumyl peroxide, and 2,3-dimethyl-2,3-diphenylbutane. Other examples include phthalocyanine metal complexes such as iron phthalocyanine, manganese phthalocyanine, and cobalt phthalocyanine, and zeolites. Other examples of the flame retardant aid include zinc fatty acids such as zinc stearate, phosphate compounds such as resorcinol bis-dixylenyl phosphate, carboxylate compounds such as tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, and antimony oxide. When the thermoplastic resin is a polyolefin resin, particularly a recycled polypropylene resin, the flame retardant aid is preferably antimony oxide.

[0053] The content of the flame retardant aid is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, and even more preferably 0.01 parts by mass or more, relative to 100 parts by mass of the thermoplastic resin, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, even more preferably 1 part by mass or less, and even more preferably 0.6 parts by mass or less. In particular, when the thermoplastic resin is a recycled polypropylene resin, the content of the flame retardant aid is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.1 parts by mass or more, and particularly preferably 1 part by mass or more, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less, relative to 100 parts by mass of the thermoplastic resin.

[0054] The resin composition of the present invention may also contain at least one metal selected from the group consisting of transition metals, alkali metals, and alkaline earth metals. Conventionally, when an extruded foam contains such a metal, it has sometimes been difficult to improve its flame retardancy. In this regard, the resin composition of the present invention contains the thermoplastic resin, the brominated flame retardant, and the organic phosphonic acid as essential components, and therefore can improve its flame retardancy despite containing such a metal (particularly a transition metal). Furthermore, the resin composition of the present invention contains the thermoplastic resin, the brominated flame retardant, and the organic phosphonic acid as essential components, and therefore may be able to achieve both flame retardancy and heat resistance despite containing such a metal (particularly a transition metal).

[0055] When the resin composition of the present invention contains the metal, it is particularly preferable that the metal is derived from a thermoplastic resin. For example, recycled resins such as recycled polystyrene may contain the metal (especially transition metals). For this reason, it has been difficult to improve the flame retardancy of extruded foam molded articles made from recycled resins such as recycled polystyrene. However, as described above, the present invention can improve the flame retardancy of extruded foam molded articles obtained from recycled resins containing the metal. Furthermore, as described above, the present invention may be able to achieve both flame retardancy and heat resistance even in extruded foam molded articles obtained from recycled resins containing the metal.

[0056] When the resin composition of the present invention contains the metal, the content thereof is, for example, preferably 100 ppm by mass or more and 2000 ppm by mass or less, more preferably 150 ppm by mass or more, and even more preferably 200 ppm by mass or more, and more preferably 1800 ppm by mass or less, and even more preferably 1500 ppm by mass or less, relative to the thermoplastic resin.

[0057] Examples of transition metals include Ti, Mn, Fe, Ni, Cu, Zn, and Zr. Examples of alkali metals include Li, Na, and K. Examples of alkaline earth metals include Mg, Ca, Sr, and Ba. The metals contained in the resin composition do not necessarily need to exist as simple metals, but can also exist in the form of metal-containing compounds. These simple metals or metal compounds may be derived from the thermoplastic resin.

[0058] The resin composition of the present invention can enhance the flame retardancy of various thermoplastic resins and can also impart excellent heat resistance in some cases. Furthermore, by forming the resin composition of the present invention into a foamable resin composition as described below, an extruded foam molded article having excellent flame retardancy can be obtained. Therefore, the resin composition of the present invention can be suitably used as a raw material for obtaining extruded foam molded articles. In particular, even extruded foam molded articles obtained from recycled resins such as recycled polystyrene can exhibit high flame retardancy and may also have improved heat resistance.

[0059] The resin composition of the present invention may also contain known resin additives, such as light stabilizers, UV absorbers, UV stabilizers, heavy metal deactivators, impact modifiers, colorants, lubricants, anti-dripping agents, crystal nucleating agents, antistatic agents, and compatibilizers, within the range that does not impair the effects of the present invention. When the foamable resin composition contains additives, the content thereof can be, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.1% by mass or less, relative to the mass of the styrene-based resin. The resin composition of the present invention may contain 50% by mass or more of the thermoplastic resin, the brominated flame retardant, and the organic phosphonic acid, preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0060] The method for preparing the resin composition of the present invention is not particularly limited, and the resin composition can be prepared, for example, by mixing the thermoplastic resin, the brominated flame retardant, the organic phosphonic acid, and one or more other components added as necessary in a predetermined ratio.

[0061] 2. Foamable resin composition The present invention also encompasses a foamable resin composition. Such a foamable resin composition may contain the resin composition of the present invention described above and a foaming agent. That is, the resin composition of the present invention can be combined with a foaming agent to form a foamable resin composition.

[0062] The foaming agent may be blended into the foamable resin composition in the foaming step described below, or may be blended into the foamable resin composition in advance before foaming.

[0063] The blowing agent can be a wide variety of known blowing agents used in foam molding. Specific examples include volatile organic blowing agents such as propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, 1-chloro-1,1-difluoroethane, monochlorodifluoromethane, monochloro-1,2,2,2-tetrafluoroethane, 1,1-difluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,3,3,3-pentafluoropropane, dichloromethane, 1,2-dichloroethane, dimethyl ether, diethyl ether, and ethyl methyl ether; inorganic blowing agents such as water, nitrogen, and carbon dioxide; and chemical blowing agents such as azo compounds. The blowing agents can be used alone or in combination of two or more.

[0064] The amount of foaming agent to be added can be appropriately set depending on the desired performance of the foam, the molding method to be used, etc. For example, the amount of foaming agent can be 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the thermoplastic resin.

[0065] In addition to the foaming agent, the foamable resin composition may also contain various components that can be contained in extruded foams. Examples of such components include metal salts of fatty acids such as fatty acid zinc salts; phosphate compounds such as phosphate esters and phosphites; heat stabilizers such as phosphite compounds, thioether compounds, hindered phenol compounds, hindered amine compounds, organotin compounds, phosphate esters, and hydrotalcite; the aforementioned flame retardant aids; and foam nucleating agents such as talc, bentonite, kaolin, mica, silica, clay, and diatomaceous earth.

[0066] The foamable resin composition can be used to form a foamed molded article by various foaming methods. For example, an extruded foamed molded article can be obtained by extruding and foaming the foamable resin composition. Such an extruded foamed molded article contains a foam of the foamable resin composition, and therefore has excellent flame retardancy. In addition, a foamed molded article obtained from the foamable resin composition may have excellent both flame retardancy and heat resistance. In particular, even if the thermoplastic resin contained in the foamable resin composition is a recycled resin such as recycled polystyrene or recycled polypropylene, it may be possible to obtain an extruded foamed molded article that has high flame retardancy and is excellent in both flame retardancy and heat resistance.

[0067] The method for producing the extruded foam molded product is not particularly limited, and for example, a wide variety of known production methods can be adopted. For example, the extruded foam molded product can be produced by a production method including the following extrusion foam molding step. Extrusion foaming step: A step in which the foamable resin composition (excluding the foaming agent) is melt-mixed in an extruder, then the foaming agent (H) is injected into the extruder, and then the mixture is extruded from the extruder nozzle into the atmosphere.

[0068] By such an extrusion foaming process, a thermoplastic resin such as recycled polystyrene or recycled polypropylene is foam-molded to obtain an extruded foam molded product of the foamable resin composition. In the extrusion foaming process, the resin composition and, if necessary, other components are fed into an extruder in any order, melt-mixed in the extruder, and foam-molded. Alternatively, some or all of the components can be mixed in advance to form a mixture, and then the mixture can be fed into the extruder.

[0069] In specifying the inventions included in the present disclosure, the components (properties, structures, functions, etc.) described in the embodiments of the present disclosure may be combined in any manner. In other words, the present disclosure includes all subject matter consisting of all combinations of the components that can be combined as described in this specification. [Example]

[0070] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0071] The raw materials (thermoplastic resin, flame retardant, organic phosphonic acid, flame retardant assistant, other chelating agents) used in the examples and comparative examples are as follows.

[0072] <Thermoplastic resin> Recycled PS: Recycled polystyrene recovered from discarded home appliances (contains Na, Ca, Zn, Ba, and Fe as metal species, with a total metal content of 230 ppm by mass) Recycled PP: Recycled polypropylene recovered from discarded home appliances (contains Na, Ca, Zn, Ba, and Fe as metal species, with a total metal content of 300 mass ppm)

[0073] <Flame retardant> SR-130: Tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether) (Dai-ichi Kogyo Seiyaku Co., Ltd. "Pyroguard SR-130") SR-720N: Tetrabromobisphenol A-bis(2,3-dibromopropyl ether) (Dai-ichi Kogyo Seiyaku Co., Ltd. "Pyroguard SR-720N") SR-245: Tris(tribromophenoxy)triazine (Dai-ichi Kogyo Seiyaku Co., Ltd. "Pyroguard SR-245")

[0074] <Organic phosphonic acid> PH-540: Ethylenediaminetetramethylenephosphonic acid (manufactured by Chelest), 5% weight loss temperature is 237°C ATMP: Aminotrismethylenephosphonic acid, 5% weight loss temperature is 194℃ PBTC: Phosphonobutanetricarboxylic acid, 5% weight loss temperature is 210℃

[0075] <Flame retardant synergist> Dicumyl: 2,3-diphenyl-2,3-dimethylbutane Zn-St: Zinc stearate (manufactured by Nitto Kasei Kogyo) LA-57: Tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4- Tetracarboxylate (ADEKA) PX-200: Resorcinol bis-dixylenyl phosphate (manufactured by Daihachi Chemical Industry Co., Ltd.) Iron phthalocyanine ATO: Antimony oxide

[0076] <Other chelating agents> EDTA: Ethylenediaminetetraacetic acid CDA-10: N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (ADEKA) EDTA-4Na: tetrasodium ethylenediaminetetraacetic acid NTA: Nitrilotriacetic acid NTA-4Na: Tetrasodium nitrilotriacetate Sodium Gluconate: Sodium Gluconate Pyrophosphate K: Potassium pyrophosphate

[0077] Example 1 The components, excluding the blowing agent, were fed into an extruder with a 65 mm diameter in the blending ratios shown in Table 1 below, and the interior of the extruder was heated to 200°C to melt and plasticize the components. The components were then kneaded continuously to prepare a foamable resin composition in the extruder. The extruder used was a two-stage extruder with diameters from 65 mm to 90 mm connected in series. As shown in Table 1, the blending amounts of each component were 100 parts by mass of thermoplastic resin, 1.25 parts by mass of flame retardant, 0.20 parts by mass of organic phosphonic acid, and 0 part by mass of flame retardant aid (i.e., none was used).

[0078] Subsequently, a predetermined amount of carbon dioxide gas as a foaming agent was injected into the tip of a 65 mm extruder (opposite side to the die of the 90 mm diameter extruder) in a separate line, and the resin temperature (in-machine temperature) was cooled to 120 °C with a 90 mm diameter extruder. Thereafter, the resin composition was extruded into the atmosphere from a die lip with a rectangular cross-section of 2.5 mm in the thickness direction and 45 mm in the width direction provided at the tip of the 90 mm diameter extruder, thereby obtaining an extrusion foamed molded body of recycled polystyrene in the shape of a rectangular parallelepiped.

[0079] (Examples 2 to 9) An extrusion foamed molded body was obtained in the same manner as in Example 1, except that the raw materials and compounding amounts shown in Table 1 were changed.

[0080] (Examples 10 to 17) An extrusion foamed molded body was obtained in the same manner as in Example 1, except that the raw materials and compounding amounts shown in Table 2 were changed.

[0081] (Comparative Examples 1 to 7) An extrusion foamed molded body was obtained in the same manner as in Example 1, except that the raw materials and compounding amounts shown in Table 3 were changed.

[0082] (Examples 18 to 24 and Comparative Examples 8 to 11) An extrusion foamed molded body was obtained in the same manner as in Example 1, except that the raw materials and compounding amounts shown in Table 4 were changed.

[0083] (Evaluation Method) <LOI (Limiting Oxygen Index)> The oxygen index was measured according to JIS K-7201, and the flame retardant performance was evaluated based on the following criteria. A: The oxygen index was 30.0 or more, and it had particularly excellent flame retardancy. B: The oxygen index was 28.0 or more and less than 30.0, and it had excellent flame retardancy. C: The oxygen index was less than 28.0, and it did not have excellent flame retardancy.

[0084] <ul-94> The flame retardancy was measured in accordance with UL-94 using a rectangular test piece (length 127 mm x width 12.7 mm x thickness 1.6 mm). V-0 (total burning time of 5 sticks is 50 seconds or less, maximum burning time is 10 seconds or less, cotton drips do not ignite), V-1 (total burning time of 5 sticks is 250 seconds or less, maximum burning time is 30 seconds or less, no cotton dripping ignition), V-2 (total burning time of 5 sticks is 250 seconds or less, maximum burning time is 30 seconds or less, cotton dripping may ignite), NR (not UL94 standard) The test was evaluated on a four-point scale, with V-0 being considered a pass.

[0085] <Dispersibility> Dispersibility was evaluated based on the following criteria: The plate-shaped molded products were obtained by slicing the extruded foam molded product during the heat resistance test described below into boards with a cutter, compressing them with a biaxial roll and then roughly crushing them with a grinder, and then feeding the resulting roughly crushed material into a Labo Plastomill, melt-kneading it at 200°C, immediately removing it from the mill, and molding it into a 3.2 mm thick plate using a cooling press. A: No particulate foreign matter was found when the plate-shaped molded product was visually observed. B: Particulate foreign matter was confirmed when the plate-shaped molded product was visually observed.

[0086] <Heat resistance> The heat resistance of the foam molded articles was evaluated based on the degree of yellowing (YI: Yellow Index) of the foam molded articles obtained in each Example and Comparative Example. Specifically, the extruded foam molded articles under test were sliced ​​into boards with a cutter, compressed with a biaxial roll, and then roughly crushed with a grinder. The roughly crushed material was placed in a Labo Plastomill, melt-kneaded at 200°C, immediately removed, and molded into a 3.2 mm-thick plate using a cooling press. The resulting plate molded article was heated in a heat press at 220°C for 7 minutes and then cooled in a cooling press. The cooled plate molded article was dissolved in methylene chloride to a concentration of 10% by mass, and the solution was filtered through a 0.45 μm filter. The resulting solution was used as a heat resistance test sample. The YI value of the sample was measured by a transmission method using a spectrophotometer (SE-6000, manufactured by Nippon Denshoku Industries Co., Ltd.), and heat resistance performance was evaluated based on the following criteria. A: The YI value was 20 or less, and the heat resistance was particularly excellent. B: The YI value exceeded 20, and the heat resistance was poor.

[0087] Tables 1 to 4 show the compounding conditions for obtaining extruded foams of each Example and Comparative Example, as well as the evaluation results of the obtained foams. Note that a blank column in each table indicates that the corresponding raw material was not used.

[0088] As is clear from Tables 1 to 4, extrusion foams obtained from resin compositions (expandable resin compositions) containing a thermoplastic resin, a brominated flame retardant, and an organic phosphonic acid were excellent in both flame retardancy and heat resistance. In particular, even though the thermoplastic resin was a recycled resin (recycled polystyrene or recycled polypropylene), they were excellent in both flame retardancy and heat resistance. It was found that the mere inclusion of a chelating agent other than an organic phosphonic acid, as in the comparative examples, was not enough to achieve both flame retardancy and heat resistance in extrusion foams made from recycled resin.

[0089] [Table 1]

[0090] Table 2

[0091] Table 3

[0092] Table 4

Claims

1. A thermoplastic resin; A brominated flame retardant, an organic phosphonic acid; At least one metal selected from the group consisting of transition metals, alkali metals, and alkaline earth metals; Contains The resin composition, wherein the thermoplastic resin is a recycled resin.

2. 2. The resin composition according to claim 1, wherein the organic phosphonic acid has a 5% weight loss temperature of 150°C or higher when heated in a nitrogen atmosphere at a temperature increase rate of 10°C / min.

3. The resin composition according to claim 1 , wherein the organic phosphonic acid is solid at 20° C.

4. The resin composition according to claim 1, wherein the organic phosphonic acid is at least one selected from the group consisting of 1-hydroxyethane-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, and ethylenediaminetetramethylenephosphonic acid.

5. The resin composition according to claim 1, wherein the brominated flame retardant is at least one selected from the group consisting of tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tris(2,3-dibromopropyl)isocyanurate, tris(tribromophenoxy)triazine, and brominated epoxy oligomers.

6. The resin composition according to claim 1 , wherein the organic phosphonic acid is contained in an amount of 0.05 parts by mass or more and 1 part by mass or less relative to 100 parts by mass of the thermoplastic resin.

7. The resin composition according to claim 1 , wherein the organic phosphonic acid is contained in an amount of 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the brominated flame retardant.

8. The resin composition according to claim 1 , wherein the metal is contained in the thermoplastic resin.

9. The resin composition according to claim 1 , wherein the thermoplastic resin contains a recycled polystyrene-based resin.

10. A foamable resin composition comprising the resin composition according to any one of claims 1 to 9 and a foaming agent.

11. An extruded foam comprising a foam of the foamable resin composition according to claim 10.

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