JP7369970B2 - resin composition - Google Patents

Description

The present disclosure relates to resin compositions.

Patent Document 1 discloses a resin composition containing 30 to 80% by mass of polyamide, 5 to 60% by mass of modified polyolefin, unmodified polyolefin, filler such as glass beads, and additives such as flame retardant. It has a core-shell type particle structure with a polyamide as a matrix, a modified polyolefin as a shell, and an unmodified polyolefin as a core. Then, dimensional stability, impact resistance, etc. are improved.

Japanese Patent Application Publication No. 9-157519

Patent Document 1 was unable to achieve the desired flame retardancy, flexural modulus, and light weight.
An object of the present disclosure is to provide a resin composition that has flame retardancy, flexural modulus, and lightness.

The resin composition in the present disclosure includes 27 to 38% by mass of polyamide, 6 to 20% by mass of polypropylene, 7 to 17% by mass of maleic acid-modified styrene-butadiene elastomer, and 20 to 20% by mass of balloon filler with a specific gravity of 0.2 to 0.7. 29% by mass, and the remainder contains at least one selected from plasticizers and flame retardants.

According to the resin composition of the present disclosure, flame retardance, flexural modulus, and lightness can be combined.

Hereinafter, embodiments will be described in detail. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially the same configurations may be omitted.

It should be noted that the following description is provided to enable those skilled in the art to fully understand the present disclosure, and is not intended to limit the subject matter recited in the claims.
(Embodiment 1)
Embodiment 1 will be described below.

[1-1. composition]
The resin composition according to the present embodiment is a balloon type resin composition having 27 to 38% by mass of polyamide, 6 to 20% by mass of polypropylene, 7 to 17% by mass of maleic acid-modified styrene-butadiene elastomer, and a specific gravity of 0.2 to 0.7. It contains 20 to 29% by mass of filler and the remainder at least one selected from plasticizers and flame retardants. Polyamide, polypropylene, maleic acid-modified styrene-butadiene elastomer, balloon filler, plasticizer, and flame retardant will be explained below in order.

[1-2. polyamide]
The type of polyamide is not particularly limited. Specific examples of polyamides include nylon 6, nylon 66, nylon 11, nylon 12, nylon 46, nylon 6T (T: terephthalic acid component), nylon 9T, nylon MXD6 (MXD: m-xylylene diamine component), etc. Examples include aliphatic polyamide. Among these, nylon 6, nylon 66, nylon 11, and nylon 12 are preferred from the viewpoint of excellent moldability, mechanical properties, and the like.

As these polyamides, one type of polyamide may be used alone, or two or more types of polyamides may be used in an appropriate combination.
The mass average molecular weight (Mw) of the polyamide is not particularly limited, but is preferably from 10,000 to 500,000 from the viewpoint of improving plasticity, especially when a plasticizer is added. Mass average molecular weight (Mw) can be determined by GPC method.

The mass ratio of polyamide in the resin composition is 27 to 38% by mass, preferably 30 to 34% by mass, and more preferably 31 to 33% by mass. By regulating the mass ratio within this range, flame retardancy, flexural modulus, and lightness can be achieved.

[1-3. Polypropylene (PP)]
As the polypropylene, unmodified polypropylene is used. The concept of polypropylene is intended to include homopolymers, random copolymers, and block copolymers. A homopolymer is a homopolymer of propylene. Random copolymers and block copolymers are copolymers of propylene and α-polyolefins other than polypropylene. Specific examples of α-polyolefin include ethylene, 1-butene, and the like. The molar ratio of α-polyolefin other than polypropylene in the random copolymer and block copolymer is preferably 20 mol% or less from the viewpoint of effectively expressing the properties of polypropylene.

The weight average molecular weight (Mw) of polypropylene is not particularly limited, but is preferably within the range of 10,000 to 500,000, more preferably within the range of 45,000 to 300,000. When the mass average molecular weight (Mw) of the polypropylene is 10,000 or more, it is possible to suppress a decrease in the rigidity of the molded product. When the mass average molecular weight (Mw) of polypropylene is 500,000 or less, it is possible to prevent a decrease in fluidity of the resin composition during molding. If a decrease in fluidity can be prevented, the resin will more easily spread throughout the mold during molding, so even thin or complex-shaped members can be molded favorably. Further, since pressure increase during melt-kneading or injection molding of the resin can be suppressed, destruction of the balloon filler due to pressure increase can be suppressed. Mass average molecular weight (Mw) can be determined by GPC method.

The mass ratio of polypropylene in the resin composition is 6 to 20 mass%, preferably 13 to 17 mass%, more preferably 14 to 16 mass%. By regulating the mass ratio within this range, flame retardancy, flexural modulus, and lightness can be achieved. In addition, if the impact strength is to be further improved, it is preferably blended in an amount of 6 to 8% by mass. By regulating the mass ratio within this range, the impact strength can be improved by achieving a balance with the blending amount of the maleic acid-modified styrene-butadiene elastomer.

[1-4. Maleic acid modified styrene-butadiene elastomer]
As the styrene constituting the maleic acid-modified styrene-butadiene elastomer, halogenated styrene may be used, and as the butadiene, isoprene (2-methyl-1,3-butadiene) may be used. Furthermore, the butadiene skeleton may be configured as an olefin by hydrogenation. Styrene-butadiene elastomers are modified with maleic acid. This improves the compatibility of polyamide, polypropylene, and balloon filler.

Specific examples of the styrene-butadiene elastomer constituting the maleic acid-modified styrene-butadiene elastomer include styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-butadiene-styrene copolymer, and acrylonitrile-butadiene copolymer. Styrene copolymer, styrene-isoprene-butadiene copolymer, styrene-butadiene-butylene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer (SEBS), Examples include styrene-ethylene-butadiene-styrene copolymer, styrene-ethylene-ethylene-propylene-styrene copolymer, styrene-isoprene-styrene copolymer, and styrene (butadiene/isoprene) styrene copolymer. Among these, maleic acid-modified styrene-ethylene-butylene-styrene copolymer (SEBS) is preferred from the viewpoint of excellent effects of the resin composition of the present disclosure.

For these maleic acid-modified styrene-butadiene elastomers, one type of maleic acid-modified styrene-butadiene elastomer may be used alone, or two or more types of maleic acid-modified styrene-butadiene elastomers may be used in an appropriate combination. May be used.

Commercially available maleic acid-modified styrene-butadiene elastomers include, for example, the Tuftec M series (manufactured by Asahi Kasei Corporation).
The mass ratio of the maleic acid-modified styrene-butadiene elastomer in the resin composition is 7 to 17% by mass, preferably 7 to 9% by mass. By regulating the mass ratio within this range, flame retardancy, flexural modulus, and lightness can be achieved. In addition, if the impact strength is to be further improved, it is preferably blended in an amount of 15 to 17% by mass. By regulating the mass ratio within this range, the impact strength can be improved by achieving a balance with the amount of polypropylene blended.

[1-5. Balloon filler]
Balloon fillers can make the resin composition light in specific gravity. Generally, thermoplastic resins such as polyamide resin and polypropylene resin have a specific gravity of 0.90 or more. When a considerable amount of flame retardant is added to improve flame retardancy, the specific gravity of the resin composition increases by about 0.1. In order to reduce the apparent specific gravity of the resin composition, in the present disclosure, a balloon filler, which is a low specific gravity structural member, is melt-kneaded into the resin composition.

As the balloon filler, either an inorganic balloon filler or an organic balloon filler may be employed. Specific examples of inorganic balloon fillers include glass balloons such as hollow glass beads, shirasu balloons, alumina balloons (perlite balloons), silica-alumina balloons (fly ash balloons), carbon balloons, zirconia balloons, and the like. Specific examples of the organic balloon filler include thermosetting organic balloons such as phenol resin balloons, thermoplastic organic balloons such as acrylonitrile balloons, and the like. Among these, hollow glass beads are preferred from the viewpoint of ease of molding during production.

These balloon fillers may be used alone or in an appropriate combination of two or more balloon fillers.
The specific gravity of the balloon filler is 0.2 to 0.7, preferably 0.3 to 0.6, more preferably 0.4 to 0.5. When the specific gravity of the balloon filler is 0.2 or more, the pressure resistance of the balloon filler can be improved. Further, when the specific gravity of the balloon filler is 0.7 or less, the weight of the resin composition can be reduced.

The pressure strength of the balloon filler is not particularly limited, but is preferably 40 to 190 MPa, more preferably 110 to 190 MPa. By specifying it within this range, it is possible to prevent the balloon filler from being destroyed and further to reduce the weight of the resin composition.

The mass ratio of the balloon filler in the resin composition is 20 to 29% by mass, preferably 26 to 29% by mass, and more preferably 27 to 28% by mass. By regulating the mass ratio within this range, flame retardancy, flexural modulus, and lightness can be achieved.

[1-6. Plasticizer]
There are no particular limitations on the plasticizer as long as it is a plasticizer that can be applied to polyamide. Examples of plasticizers include sulfonamides such as aromatic or aliphatic sulfonamides, oxybenzoic acid esters, polycyclic aromatic compounds, N-alkyl aliphatic sulfonamides, orthophosphates, and esters of aliphatic carboxylic acids. , lactams, lactones, cyclic ketones, adducts of oxycarboxylic acids and alkylene oxides, amylcyclohexanol carbonates and tetrahydrofurfuryl carbonates, chlorinated aromatic hydrocarbons and their ethers, polyamides and ethylene oxides. Examples include adducts, condensates of urethane and formaldehyde, condensates of isocyanates and polyoxy compounds, and amorphous polyamides.

Specific examples of sulfonamides include N-butylbenzenesulfonamide, N-hexylbenzenesulfonamide, N-decylbenzenesulfonamide, N-cyclohexylbenzylsulfonamide, and toluene derivatives thereof, such as p-toluene. Sulfonamide, N-ethyl-p-toluenesulfonamide, N-ethyl-o,p-toluenesulfonamide (o,p mixture), N-butyl-p-toluenesulfonamide, N-hexyl-p-toluenesulfonamide , N-decyl-p-toluenesulfonamide, N-cyclohexyl-p-toluenesulfonamide, and the like.

Specific examples of oxybenzoic acid esters include p-oxybenzoic acid ester and the like.
Specific examples of polycyclic aromatic compounds include fluorene derivatives and the like.

Specific examples of orthophosphates include monooctyl diphenyl phosphate, cresyl phenyl phosphate, xylenyl diphenyl phosphate, and the like.
Specific examples of esters of aliphatic carboxylic acids include dioctyl azelate, dioctyl sebacate, and the like.

Among these plasticizers, sulfonamides, oxybenzoic acid esters, and polycyclic aromatic compounds are preferred from the viewpoints of excellent compatibility with polyamide and excellent plasticizing effect on the resin composition.

These plasticizers may be used alone or in a suitable combination of two or more plasticizers.
The mass ratio of the plasticizer in the resin composition is preferably 1 to 2.2 mass%, more preferably 1.5 to 2.0 mass%. When the mass ratio of the plasticizer is 1% by mass or more, plasticization can be imparted to the resin composition. Further, when the mass ratio of the plasticizer is 2.2% by mass or less, a good surface appearance can be maintained.

[1-7. Flame retardants]
Examples of flame retardants include halogen flame retardants, phosphorus flame retardants such as phosphate ester flame retardants and organic phosphorus flame retardants, metal salt flame retardants, silicone flame retardants, ammonium polyphosphate flame retardants, and triazine flame retardants. Examples include flame retardants.

Specific examples of halogen flame retardants include decabromodiphenyl ether, tetrabromobisphenol A, tetrabromobisphenol S, and 1,2-bis(2',3',4',5',6'-pentabromophenyl). Ethane, 1,2-bis(2,4,6-tribromophenoxy)ethane, 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, 2,6 - or 2,4-dibromophenol, brominated epoxy resin, brominated polycarbonate, brominated polystyrene, brominated polyacrylate, ethylene bistetrabromophthalimide, hexabromocyclododecane, hexabromobenzene, pentabromobenzyl acrylate, 2,2 -bis[4'(2'',3''-dibromopropoxy)-,3',5'-dibromophenyl]-propane, bis(3,5-dibromo-4-dibromopropoxyphenyl)sulfone, tris(2 , 3-dibromopropyl) isocyanurate, chlorinated paraffin, chlorinated polyethylene, chlorinated polypropylene, perchloropentacyclodecane, dodecachlorododecahydrodimethanodibenzocyclooctene, dodecachloro Examples include chlorine-based flame retardants containing chlorine-containing compounds such as octahydrodimethanodibenzofuran. Here, from the viewpoint of exhibiting a flame retardant effect with a relatively low additive amount, 1,2-bis(2',3',4',5',6'-pentabromophenyl)ethane (ethylenebis(pentabromophenyl) )) is preferred.

Specific examples of phosphorus-based flame retardants include aromatic phosphate esters such as triphenyl phosphate, tricresyl phosphate, trimethyl phosphate, triethyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, and 2-ethylhexyl diphenyl phosphate; Monophosphate compounds, phosphate ester compounds such as phosphate oligomer compounds, halogen-containing phosphate ester compounds such as trisdichloropropyl phosphate, trischloroethyl phosphate, trischloropropyl phosphate, condensed phosphate ester compounds, polyphosphates, red phosphorus Examples thereof include phosphinate compounds, phosphonate compounds, phosphonitrile oligomer compounds, phosphonic acid amide compounds, and the like.

Specific examples of metal salt flame retardants include those in which some inorganic salts such as sodium antimonate, antimony trioxide, and antimony pentoxide are used in combination with halogen flame retardants as flame retardant aids, and organic sulfonic acids. Examples include organic metal salt flame retardants such as alkali (earth) metal salts, metal borate flame retardants, and metal stannate flame retardants.

These flame retardants may be used alone or in an appropriate combination of two or more flame retardants.
Additionally, a drip-preventing agent (polytetrafluoroethylene having fibril-forming ability, etc.) or the like may be separately added and used in combination with a flame retardant.

The mass ratio of the flame retardant in the resin composition is preferably 12.6 to 15.2 mass%, more preferably 13 to 15 mass%. When the mass ratio of the flame retardant is 12.6% by mass or more, flame retardancy can be imparted to the resin composition. Furthermore, when the mass ratio of the flame retardant is 15.2% by mass or less, the weight of the resin composition can be reduced.

[1-8. Manufacturing method of resin composition]
The resin composition (pellets) can be produced by a dry method as follows. That is, at least one selected from polyamide, polypropylene, maleic acid-modified styrene-butadiene elastomer, balloon filler with a specific gravity of 0.2 to 0.7, a plasticizer, and a flame retardant is mixed in a predetermined manner in a twin-screw kneading extruder. and other kneading extruders. Polyamide, polypropylene, and maleic acid-modified styrene-butadiene elastomer are melted in a kneading extruder. The plasticizer improves the fluidity of the polyamide, and the balloon filler and flame retardant are dispersed in the molten mixed resin while reducing shear stress. Furthermore, the balloon filler and flame retardant are subjected to shearing action in the kneading extruder and are uniformly dispersed in the molten mixed resin. The melt-kneaded product extruded from the kneading extruder is cooled with water, for example, and becomes pellets. The dimensions of the pellets are not particularly limited.

[1-9. Manufacturing method of molded product]
Various molded products can be manufactured by using a resin composition (pellet) as a molding material and using a known molding method such as injection molding, extrusion molding, or cast molding. Since the resin composition contains at least one selected from polyamide, polypropylene, maleic acid-modified styrene-butadiene elastomer, balloon filler, and the remainder a plasticizer and a flame retardant, the obtained molded product has no It has high flammability, flexural modulus, and light weight.

[1-10. Effects, etc.]
As described above, in the resin composition of the present embodiment, polyamide is 27 to 38% by mass, polypropylene is 6 to 20% by mass, maleic acid-modified styrene-butadiene elastomer is 7 to 17% by mass, and specific gravity is 0.2 to 0. 20 to 29% by mass of the balloon-based filler No. 7, and the balance contains at least one selected from a plasticizer and a flame retardant. This makes it possible to have flame retardancy, flexural modulus, and light weight.

Further, in this embodiment, polyamide is 30 to 34% by mass, polypropylene is 13 to 17% by mass, maleic acid-modified styrene-butadiene elastomer is 7 to 9% by mass, and balloon filler is 26 to 29% by mass. It's okay. Thereby, better flame retardancy, better flexural modulus, and lighter weight can be achieved.

In addition, in this embodiment, polyamide is 31 to 33% by mass, polypropylene is 14 to 16% by mass, maleic acid-modified styrene-butadiene elastomer is 7 to 9% by mass, and balloon filler is 27 to 28% by mass. It's okay. This makes it possible to achieve even better flame retardancy, flexural modulus, and weight reduction.

In addition, in this embodiment, polyamide is 31 to 33% by mass, polypropylene is 6 to 8% by mass, maleic acid-modified styrene-butadiene elastomer is 15 to 17% by mass, and balloon filler is 27 to 28% by mass. It's okay. This makes it possible to balance the blending amount of polypropylene and the maleic acid-modified styrene-butadiene elastomer, thereby improving impact strength.

Further, in this embodiment, the plasticizer may be 1 to 2.2% by mass, and the flame retardant may be 12.6 to 15.2% by mass. Thereby, plasticity can be improved while maintaining a good surface appearance of the resin composition. Further, flame retardancy can be improved while reducing the weight of the resin composition.

Further, in this embodiment, the mass average molecular weight of the polyamide may be from 10,000 to 500,000. Thereby, plasticity can be improved. In particular, plasticity can be improved when a plasticizer is added.

Further, in this embodiment, the mass average molecular weight of the polypropylene may be from 10,000 to 500,000. Thereby, a decrease in rigidity of the molded product can be suppressed. Further, it is possible to prevent a decrease in fluidity of the resin composition during molding. If a decrease in fluidity can be prevented, the resin will more easily spread throughout the mold during molding, so even thin or complex-shaped members can be molded favorably. Further, since pressure increase during melt-kneading or injection molding of the resin can be suppressed, destruction of the balloon filler due to pressure increase can be suppressed.

Further, in this embodiment, the plasticizer may be at least one type selected from sulfonamides, oxybenzoic acid esters, and polycyclic aromatic compounds. Thereby, an excellent effect of imparting plasticization to the resin composition can be obtained.

[2. Other embodiments]
As mentioned above, Embodiment 1 has been described as an example of the technology disclosed in this application. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments in which changes, replacements, additions, omissions, etc. are made. Furthermore, it is also possible to create a new embodiment by combining the components described in the first embodiment.

Therefore, other embodiments will be illustrated below.
The embodiments described above may contain one or more types of additives other than those described above, within a range that does not impede the properties of the resin composition of the present disclosure. Specific examples of additives include colorants, fillers, antioxidants, ultraviolet absorbers, antistatic agents, and the like.

Note that the above-described embodiments are for illustrating the technology of the present disclosure, and therefore various changes, substitutions, additions, omissions, etc. can be made within the scope of the claims or equivalents thereof.

EXAMPLES Hereinafter, the present disclosure will be specifically explained using examples, but the present disclosure is not limited to the following examples.
(Example 1)
Polyamide, polypropylene, maleic acid-modified styrene-butadiene elastomer, balloon filler, plasticizer, and flame retardant were weighed and dry blended to have the ratios (% by mass) shown in Table 1. Next, the mixture was melt-kneaded and dispersed using a twin-screw kneading extruder (manufactured by Technovel Co., Ltd., model: KZW15TW) at a kneading temperature of 240° C., and then cooled with water to produce pellets.

Polyamide: Amilan CM1007 (manufactured by Toray Industries, nylon 6, mass average molecular weight 250,000)
Polypropylene: Novatec PP BC03B (manufactured by Nippon Polypro Co., Ltd., mass average molecular weight 150,000)
Maleic acid-modified styrene-butadiene elastomer: Tuftec M1913 (manufactured by Asahi Kasei Corporation, maleic acid-modified SEBS)
Balloon filler: Glass Bubbles iM16K (manufactured by 3M, hollow glass filler, specific gravity 0.46, pressure resistance 110 MPa)
Plasticizer: OGSOL MF-11 (manufactured by Osaka Gas Chemical Co., Ltd., bis-phenol-ethanol-fluorene (BPEF))
Flame retardant: Saytex 8010 (manufactured by Albemarle Japan Co., Ltd., ethylene bis(pentabromophenyl))
(Examples 2 to 9)
Pellets made of a resin composition were produced in the same manner as in Example 1, except that they were weighed to have the ratios shown in Table 1.

(Comparative Examples 1 to 3)
Pellets made of a resin composition were produced in the same manner as in Example 1, except that polypropylene, plasticizer, and flame retardant were not used, and the pellets were weighed to have the ratios shown in Table 1.

(Comparative Examples 4 and 5)
Pellets made of a resin composition were produced in the same manner as in Example 1, except that a plasticizer and a flame retardant were not used and the pellets were weighed to have the ratios shown in Table 1.

(Comparative Examples 6, 7, 9, 10)
Pellets made of a resin composition were produced in the same manner as in Example 1, except that they were weighed to have the ratios shown in Table 1.

(Comparative example 8)
Pellets made of a resin composition were produced in the same manner as in Example 1, except that no flame retardant was used and the pellets were weighed to have the ratios shown in Table 1.

(bending modulus)
Test pieces specified in ISO178 were prepared using the pellets of each Example and Comparative Example. A bending test specified in JIS K 7171 was performed on each test piece. Table 1 shows the measurement results of the flexural modulus.

(Charpy impact test)
The Charpy impact test is an impact test in which a prismatic test piece with a notch is subjected to a high-speed impact to break the test piece and evaluate the energy required to break it and the toughness of the test piece. It is. The Charpy impact test was conducted based on the provisions of JIS K 7111. Table 1 shows the measurement results of the impact strength determined by the Charpy impact test.

(Specific gravity of resin composition)
The specific gravity of the resin composition was determined by the underwater substitution method described in JIS K 7112. Table 1 shows the measurement results of specific gravity.

(Flame retardancy test)
A flame retardant evaluation was conducted according to Underwriter's Laboratories Inc.'s UL-94 standard. In the Vertical Burning Test, first, a test piece in the form of a strip is held vertically and held at its upper end, and the flame of a gas burner is applied to the lower end for 10 seconds. Next, when the flame of the gas burner was removed and the flame went out, the flame of the gas burner was heated indirectly for another 10 seconds and the flame was removed. Judgment is based on the total flammable combustion time and the presence or absence of ignition due to drip (particles falling from the test piece), and ranks them as UL94V-2, UL94V-1, and UL94V-0 in descending order of combustibility. In this test, it was judged as "pass" if the UL94V-2 standards were met, and "fail" if the requirements were not met. The flame retardant measurement results are shown in Table 1.

The test piece has a length of 127 mm and a width of 12.7 mm, and has five thicknesses ranging from the minimum to the maximum of 12.7 mm. The thickness increase was determined not to exceed 3.18 mm in each case.
(injection pressure)
The maximum pressure when molding was performed at an injection temperature of 240° C. using a mold having a dumbbell piece shape was measured. Table 1 shows the measurement results of the injection pressure.

The molded products obtained from the resin compositions of each example all have a predetermined flame retardancy, and have a flexural modulus of 1,500 MPa or more and a specific gravity of 0.99 or less. It was confirmed that a resin composition that is lightweight can be obtained. Further, in each of the Examples, the injection pressure was 135 MPa or less, and the fluidity during molding was good. Further, in each of the examples, the impact strength determined by the Charpy impact test was 3.0 kJ/m ² or more, and the molded product had excellent impact strength.

The resin composition of the present disclosure can be used, for example, as parts of home appliances such as vacuum cleaners, power tools, hair dryers, hair irons, hair curlers, kettles, and handheld cookers.

Claims (8)

27-38% by mass of polyamide, 6-20% by mass of polypropylene, 7-17% by mass of maleic acid-modified styrene-butadiene elastomer, 20-29% by mass of balloon filler with a specific gravity of 0.2-0.7, the remainder being plasticizer. and a resin composition containing at least one selected from flame retardants. Claim 1, wherein the polyamide is 30 to 34% by mass, the polypropylene is 13 to 17% by mass, the maleic acid-modified styrene-butadiene elastomer is 7 to 9% by mass, and the balloon filler is 26 to 29% by mass. The resin composition described. 3. The polyamide is 31 to 33% by mass, the polypropylene is 14 to 16% by mass, the maleic acid-modified styrene-butadiene elastomer is 7 to 9% by mass, and the balloon filler is 27 to 28% by mass. The resin composition described. Claim 1, wherein the polyamide is 31 to 33% by mass, the polypropylene is 6 to 8% by mass, the maleic acid-modified styrene-butadiene elastomer is 15 to 17% by mass, and the balloon filler is 27 to 28% by mass. The resin composition described. The resin composition according to any one of claims 1 to 4, wherein the plasticizer is 1 to 2.2% by mass, and the flame retardant is 12.6 to 15.2% by mass. The resin composition according to any one of claims 1 to 5, wherein the polyamide has a mass average molecular weight of 10,000 to 500,000. The resin composition according to any one of claims 1 to 6, wherein the polypropylene has a mass average molecular weight of 10,000 to 500,000. The resin composition according to any one of claims 1 to 7, wherein the plasticizer is at least one selected from sulfonamides, oxybenzoic acid esters, and polycyclic aromatic compounds.