Electromagnetic wave shielding composition having thermoplastic resin or thermoplastic elastomer, and molded article formed from same

Abstract

The present invention addresses the problem of providing an electromagnetic wave shielding composition which has electromagnetic wave shielding performance and is capable of suppressing an increase in fluidity when heated. The above-mentioned problem is solved by an electromagnetic wave-shielding composition comprising at least one component (A) selected from the group consisting of thermoplastic resins and thermoplastic elastomers and a soft magnetic powder (B) at a mass ratio (component (A) / component (B)) in the range of 5 / 95 to 95 / 5, the composition further contains 0.02-1.4 parts by mass of component (C), which is at least one compound selected from among phosphite ester compounds and phosphate ester compounds, per 100 parts by mass of the total of the component (A) and the component (B), and a sheet having a thickness of 2.0 mm, which is obtained by molding the composition, exhibits a magnetic field shielding performance of 3 dB or more at both frequencies of 1 MHz and 10 MHz as measured by the KEC method.

Description

Technical Field

[0001] This invention relates to an electromagnetic wave shielding composition capable of suppressing the increase in fluidity during heating. Background Technology

[0002] Unwanted electromagnetic waves generated by various electronic devices can affect other electronic devices, causing malfunctions. To mitigate the negative effects of these unwanted electromagnetic waves, a common countermeasure is to shield them using metal casings, plates, or similar materials.

[0003] However, using metal casings or plates is inconvenient due to their increased weight and limited shape flexibility. Therefore, to suppress the drawbacks of unwanted electromagnetic waves, electromagnetic wave shielding molded products are widely used, which are made by mixing and dispersing magnetic powder in rubber, synthetic resins, etc., and then processing them into various molded forms such as sheets, tubes, and shells.

[0004] As an electromagnetic wave shielding material, it is proposed to add soft magnetic metal powders such as silicon steel, ferrite, permalloy, iron-silicon-aluminum, and permalloy.

[0005] Patent Document 1 describes an example of a resin composition containing soft magnetic powder that has excellent electromagnetic wave shielding properties in the low-frequency region and can be heat-melted and molded. It discloses that by containing soft magnetic powder in thermoplastic resin EVA (ethylene-vinyl acetate copolymer resin), a sheet based on extrusion molding or the like is obtained, thereby imparting shielding properties for magnetic field components at 0.3MHz and 1MHz.

[0006] In addition, Patent Document 2 describes an example of a resin composition for manufacturing an injection-molded body with low-frequency magnetic field shielding properties. It discloses that by containing iron-silicon-aluminum alloy (Fe-Si-Al alloy) powder with a specified median particle size and aspect ratio in a polyamide resin, which is a thermoplastic resin, magnetic field shielding properties in the range of 0.1 to 100 MHz are imparted.

[0007] Prior art literature

[0008] Patent documents

[0009] Patent Document 1: International Publication No. 2021 / 246442

[0010] Patent Document 2: Japanese Patent Application Publication No. 2012-151205 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] However, as disclosed in Patent Documents 1 and 2, it is clear that compositions containing thermoplastic resins, thermoplastic elastomers, and soft magnetic metal powder exhibit increased fluidity upon heating. Increased fluidity sometimes leads to overfilling during molding, adversely affecting the mass production of the resulting molded articles. This effect is particularly significant in injection molding.

[0013] Therefore, the object of the present invention is to provide an electromagnetic wave shielding composition, which is a composition having a thermoplastic resin or a thermoplastic elastomer, having electromagnetic wave shielding properties, and being able to suppress the increase of fluidity during heating.

[0014] Solutions for solving problems

[0015] The inventors conducted repeated and in-depth research to solve the aforementioned problems. As a result, they discovered that by adding a predetermined amount of at least one compound selected from phosphite and phosphate esters to a thermoplastic resin or thermoplastic elastomer containing soft magnetic metal powder, it is possible to suppress the increase in fluidity during heating while maintaining electromagnetic wave shielding performance, thus completing the present invention. More specifically, the present invention provides the following:

[0016] [1] An electromagnetic wave shielding composition, characterized in that it comprises at least one component (A) selected from thermoplastic resins and thermoplastic elastomers and a soft magnetic metal powder (B) in a mass ratio ((A) component / (B) component) ranging from 5 / 95 to 95 / 5.

[0017] The compound further comprises at least one component (C) selected from phosphite compounds and phosphate compounds, in an amount of 0.02 to 1.4 parts by mass relative to a total of 100 parts by mass of the aforementioned components (A) and (B).

[0018] When the KEC method was used to measure the thickness of a 2.0 mm sheet formed from the aforementioned composition, it showed a magnetic field shielding performance of more than 3 dB at both 1 MHz and 10 MHz.

[0019] [2] The electromagnetic wave shielding composition according to [1] is characterized in that the ΔMFR, calculated by the following formula based on the measurement according to ISO 1133, is less than 20 g / 10 min.

[0020] ΔMFR = (MFR at 25 minutes of stay) - (MFR at 5 minutes of stay)

[0021] (In the formula, the MFR at 25 minutes of residence is the melt flow rate measured with the preheating time set to 25 minutes, and the MFR at 5 minutes of residence is the melt flow rate measured with the preheating time set to 5 minutes. It should be noted that the load for measuring the melt flow rate is 2160g, and the measurement temperature is the melting point of component (A) + 25℃.)

[0022] [3] The electromagnetic wave shielding composition according to [1] or [2] is characterized in that the aforementioned component (A) contains one or more selected from the group consisting of polyester resins, polyester elastomers, polycarbonate resins, polyamide resins, polyphenylene sulfide resins and polyolefin resins.

[0023] [4] The electromagnetic wave shielding composition according to any one of [1] to [3] is characterized in that the aforementioned component (B) is at least one powder selected from the group consisting of Fe-Si alloys, Fe-Si-Al alloys, Fe-Si-Cr alloys and ferrites.

[0024] [5] The electromagnetic wave shielding composition according to any one of [1] to [4] is characterized in that the shape of the aforementioned component (B) is flat.

[0025] [6] The electromagnetic wave shielding composition according to any one of [1] to [5], wherein the average particle size D50 of the aforementioned (B) component is 1 to 100 μm.

[0026] [7] The electromagnetic wave shielding composition according to any one of [1] to [6] is characterized in that the aforementioned component (C) is selected from at least one of the compounds shown in the following formula (C1-1), the following formula (C1-2) and the following formula (C2-1).

[0027]

[0028] In formula (C1-1), R 1 This indicates an aliphatic hydrocarbon group with 1 to 30 carbon atoms or an aromatic hydrocarbon group with 6 to 30 carbon atoms.

[0029]

[0030] In formula (C1-2), R 2 This indicates an aliphatic hydrocarbon group with 1 to 30 carbon atoms or an aromatic hydrocarbon group with 6 to 30 carbon atoms.

[0031]

[0032] In formula (C2-1), R 4 It is an aliphatic hydrocarbon group with 1 to 30 carbon atoms, where n is 1 or 2.

[0033] [8] The electromagnetic wave shielding composition according to any one of [1] to [7], wherein the content of the aforementioned component (C) is 0.05 to 2.7 parts by mass relative to 100 parts by mass of the aforementioned component (B).

[0034] [9] A molded article formed from any one of [1] to [8] electromagnetic wave shielding composition.

[0035] Use of the electromagnetic wave shielding composition described in any one of

[10] [1] to [8] for shielding electromagnetic waves with frequencies from 1 kHz to 1 GHz.

[0036] The effects of the invention

[0037] According to the present invention, by mixing at least one of the (C) components selected from phosphite compounds and phosphate compounds with at least one of the (A) components selected from thermoplastic resins and thermoplastic elastomers and the (B) component of soft magnetic metal powder in a specific amount, a composition with excellent electromagnetic wave shielding performance and the ability to suppress the increase of fluidity during heating can be obtained. Detailed Implementation

[0038] The embodiments of the present invention will now be described in detail. However, the present invention is not limited to these embodiments, and can be implemented by appropriate modifications within the scope of the present invention's objectives. Furthermore, descriptions of repeated parts may sometimes be omitted, but this does not limit the scope of the invention.

[0039] [(A) ingredient]

[0040] In the electromagnetic wave shielding composition of the present invention, component (A) used as a base component (matrix component) is at least one selected from thermoplastic resins and thermoplastic elastomers.

[0041] The aforementioned thermoplastic resins are not particularly limited, but representative examples include polyester resins, polycarbonate resins, polyamide resins, polyphenylene sulfide resins, and polyolefin resins. These thermoplastic resins can be used alone or in combination of two or more.

[0042] There are no particular limitations on the thermoplastic elastomers mentioned above; polyester elastomers are a representative example.

[0043] (A) Components can be used alone or in combination of two or more.

[0044] In component (A), resins and / or elastomers having an ester backbone and / or amide backbone in the repeating portion of the main chain, such as polyester resins, polyester elastomers, polycarbonate resins, and polyamide resins (hereinafter referred to as ester / amide resins and / or elastomers), are preferred; resins and / or elastomers having an ester backbone in the repeating portion of the main chain (hereinafter referred to as ester resins and / or elastomers) are more preferred. When component (A) (especially ester / amide resins and / or elastomers) is melt-blended with soft magnetic metal powder as component (B), its fluidity can be easily increased by heating. However, in this invention, by pre-coexisting at least one of phosphite compounds and phosphate compounds as component (C), the increase in fluidity can be suppressed.

[0045] As component (A), ester / amide resins and / or elastomers are preferred, more preferably at least one selected from the group consisting of polyester resins (excluding liquid crystal polyester resins), polyamide resins, and polyester elastomers, further preferably at least one selected from the group consisting of polyester resins (excluding liquid crystal polyester resins) and polyester elastomers, and particularly preferably polyester resins (excluding liquid crystal polyester resins). The low water absorption of polyester resins (excluding liquid crystal polyester resins) and polyester elastomers is useful for ensuring good dimensional stability of the resulting molded articles.

[0046] As a polyester resin, an aromatic polyester resin with aromatic dicarboxylic acid units and diol units as structural units is preferred.

[0047] The aromatic dicarboxylic acids that form the above-mentioned structural units are not particularly limited. Specific examples include phthalic acids such as terephthalic acid, isophthalic acid, and phthalic acid; naphthalic acids such as 2,6-naphthalenedicarboxylic acid and 1,5-naphthalenedicarboxylic acid; compounds with two carboxylphenyl groups such as 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid and diphenyl-p,p-dicarboxylic acid; and their functional derivatives. These aromatic dicarboxylic acids can be used alone or in combination of two or more.

[0048] The aromatic dicarboxylic acids that form the above-mentioned structural units are preferably terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and diphenyl-p,p-dicarboxylic acid, which tend to crystallize quickly and have good formability. Terephthalic acids such as terephthalic acid and isophthalic acid, and naphthalenedicarboxylic acids such as 2,6-naphthalenedicarboxylic acid are particularly preferred.

[0049] It should be noted that the aforementioned aromatic dicarboxylic acid unit is introduced, for example, through ester synthesis using aromatic dicarboxylic acids, aromatic dicarboxylic acid esters, or their salts as raw materials. Examples of aromatic dicarboxylic acid esters that serve as raw materials include monoalkyl esters and dialkyl esters of aromatic dicarboxylic acids, with dialkyl esters of aromatic dicarboxylic acids being preferred. Preferred raw materials include terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, 2,6-naphthalenedicarboxylic acid, and dimethyl 2,6-naphthalenedicarboxylic acid.

[0050] Furthermore, in aromatic polyester resins, a portion of the aromatic dicarboxylic acid units can be replaced with dicarboxylic acid units other than aromatic dicarboxylic acid units (hereinafter referred to as other dicarboxylic acid units). Examples of other dicarboxylic acids that can be considered as the aforementioned other dicarboxylic acid units include saturated or unsaturated aliphatic dicarboxylic acids and their functional derivatives, such as adipic acid, sebacic acid, succinic acid, glutaric acid, 1,10-decanedicarboxylic acid, and dimer acids; alicyclic dicarboxylic acids and their functional derivatives, such as hexahydroterephthalic acid, hexahydroisophthalic acid, and cyclohexanedicarboxylic acid; etc. The percentage of other dicarboxylic acid units in the total of aromatic dicarboxylic acid units and other dicarboxylic acid units (all dicarboxylic acid units) is preferably less than 50 mol%, more preferably less than 40 mol%, and even more preferably less than 30 mol%. If the aforementioned amount is less than 50 mol%, the polyester resin exhibits good crystallinity and tends to have better formability and heat resistance.

[0051] The diols (units) constituting aromatic polyester resins are not particularly limited. Specifically, examples include aliphatic diols such as alkylene glycols (e.g., ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol); alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanediol; aromatic diols such as bisphenol A, hydroquinone, and 2,2-bis(4-β-hydroxyethoxyphenyl)propane; etc. These diols (units) can be used alone or in combination of two or more.

[0052] The diol (unit) mentioned above is preferably selected from at least one of the group consisting of aliphatic diols and alicyclic diols, more preferably alkylene diols having 2 to 8 carbon atoms. More specifically, it is selected from at least one of the group consisting of ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and 1,4-cyclohexanediol, more preferably at least one of ethylene glycol and 1,4-butanediol.

[0053] As aromatic polyester resins, examples include polyethylene terephthalate, polyethylene terephthalate, polyethylene butylene terephthalate, polycyclohexanedimethyl terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyethylene naphthalate, polyethylene butylene naphthalate, polyethylene isophthalate / ethylene terephthalate copolymer, polyethylene isophthalate / propylene terephthalate copolymer, and polyethylene isophthalate / butylene terephthalate copolymer. Poly(ethylene terephthalate) / polyethylene naphthalate copolymer, poly(propylene terephthalate) / propylene naphthalate copolymer, poly(butylene terephthalate) / butylene naphthalate copolymer, poly(butylene terephthalate) / butylene decanedicarboxylate copolymer, poly(ethylene terephthalate) / dimethyl cyclohexane terephthalate copolymer, poly(ethylene terephthalate) / polyethylene succinate copolymer, poly(propylene terephthalate) / propylene succinate copolymer, poly(butylene terephthalate) / Butyl succinate copolymer, polyethylene terephthalate / ethylene adipate copolymer, polyethylene terephthalate / propylene adipate copolymer, polyethylene terephthalate / butylene adipate copolymer, polyethylene terephthalate / ethylene sebacic acid copolymer, polyethylene terephthalate / propylene sebacic acid copolymer, polyethylene terephthalate / butylene sebacic acid copolymer, polyethylene terephthalate / ethylene isophthalate / ethylene adipate copolymer Poly(propylene terephthalate) / (propylene isophthalate) / (propylene adipate) copolymer, poly(butylene terephthalate) / (butylene isophthalate) / (butylene succinate) copolymer, poly(butylene terephthalate) / (butylene isophthalate) / (butylene adipate) copolymer, poly(butylene terephthalate) / (butylene isophthalate) / (butylene sebacate) copolymer, bisphenol A / terephthalic acid polymer, bisphenol A / (isophthalic acid) polymer, bisphenol A / terephthalic acid / (isophthalic acid) copolymer, etc.

[0054] In addition, liquid crystal polyester resins can also be cited as examples of the aforementioned polyester resins. Examples of liquid crystal polyester resins include p-hydroxybenzoic acid / ethylene glycol / terephthalic acid copolymers, hydroxynaphthoic acid / p-hydroxybenzoic acid copolymers, and biphenol / benzoic acid / p-hydroxybenzoic acid copolymers.

[0055] Among these, the aforementioned polyester resin is preferably an aromatic polyester resin other than a liquid crystal polyester resin. Of the aromatic polyester resins other than liquid crystal polyester resins, polymers with aromatic dicarboxylic acids and alkylene glycols as structural units are preferred, more preferably polymers with aromatic dicarboxylic acids and alkylene glycols having 2 to 8 carbon atoms as structural units, and even more preferably polymers with terephthalic acid and alkylene glycols having 2 to 8 carbon atoms as structural units. Furthermore, from the viewpoint of heat resistance and moldability, at least one of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) is preferred, with polybutylene terephthalate (PBT) being particularly preferred.

[0056] The intrinsic viscosity of the polyester resin is preferably 0.5 to 1.8 dl / g, more preferably 0.6 to 1.5 dl / g. By setting the intrinsic viscosity of the polyester resin to a specified value or higher, durability can be improved; by setting the intrinsic viscosity of the polyester resin to a specified value or lower, processability for injection molding and the like can be improved.

[0057] As a polyester elastomer, it is preferably a polyester elastomer formed by bonding hard segments of polyester with aromatic dicarboxylic acids and aliphatic and / or alicyclic diols as structural units with at least one soft segment selected from aliphatic polyethers, aliphatic polyesters and aliphatic polycarbonates.

[0058] As an aromatic dicarboxylic acid constituting a hard segment of the polyester, examples of aromatic dicarboxylic acids exemplified in the aforementioned aromatic polyester resins can be cited, and the preferred embodiment is also the same. Furthermore, similar to the aforementioned aromatic polyester resins, dicarboxylic acids other than aromatic dicarboxylic acids can be included as structural units, and the preferred embodiment is also the same as described above.

[0059] In addition, aliphatic and alicyclic diols constituting the hard segment of the polyester can be exemplified by the aforementioned aromatic polyester resins, and the preferred method is also the same.

[0060] The aforementioned hard segment is preferably a polyester with aromatic dicarboxylic acids and alkylene glycols having 2 to 8 carbon atoms as structural units, and more preferably a polyester with terephthalic acid and alkylene glycols having 2 to 8 carbon atoms as structural units. Furthermore, from the viewpoint of heat resistance and moldability, at least one of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) is preferred, with polybutylene terephthalate (PBT) being particularly preferred.

[0061] By pre-producing an aromatic polyester suitable as a constituent of the hard segment, and then copolymerizing it with a soft segment component, the aromatic polyester can be readily obtained using conventional polyester manufacturing methods. Furthermore, this polyester preferably has a number average molecular weight of 10,000 to 40,000.

[0062] Aliphatic polyethers constituting the soft segments of the aforementioned polyester elastomers include polyethers with one or more of the following structural units: polyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxyhexamethylene glycol, polyoxytrimethylene glycol, copolymers of ethylene oxide and propylene oxide, ethylene oxide adducts of polyethylene glycol, and copolymers of ethylene oxide and tetrahydrofuran. The number-average molecular weight of the aliphatic polyether is, for example, 300 to 5000, preferably 500 to 4000, and more preferably 700 to 2500.

[0063] Examples of aliphatic polyesters constituting the aforementioned soft segments include poly(ε-caprolactone), polyheptanolide, polycaprolactone, and polybutylene adipate, which are aliphatic polyesters with ester groups repeating alkylene groups having 2 to 12 carbon atoms. The number average molecular weight of the aliphatic polyester is, for example, 300 to 5000, preferably 500 to 4000, and more preferably 700 to 2000.

[0064] As the aliphatic polycarbonate constituting the aforementioned soft segment, examples include resins composed of carbonate units and aliphatic diol units. Among the aforementioned aliphatic diols, those with 2 to 12 carbon atoms are preferred. Examples of these aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,9-nonanediol, and 2-methyl-1,8-octanediol. Especially from the viewpoint of the softness and low-temperature properties of the resulting polyester elastomer, aliphatic diols with 5 to 12 carbon atoms are preferred. These components can be used alone or in combination of two or more as needed. The number-average molecular weight of the aliphatic polycarbonate is, for example, 300 to 15,000, preferably 500 to 13,000.

[0065] In polyester elastomers, the composition ratio of hard segments to soft segments (hard segments / soft segments) is preferably 40 / 60 to 95 / 5 by mass, more preferably 50 / 50 to 95 / 5, and even more preferably 55 / 45 to 90 / 10.

[0066] The specific viscosity of the polyester elastomer is preferably 0.5 dl / g or more and 3.5 dl / g or less, more preferably 1.0 dl / g or more and 3.0 dl / g or less, and even more preferably 1.1 dl / g or more and 2.8 dl / g or less. By setting the specific viscosity of the polyester elastomer to a specified value or higher, durability can be improved; by setting the specific viscosity of the polyester elastomer to a specified value or lower, processability such as injection molding can be improved.

[0067] The acid value of the polyester elastomer is preferably 5 to 200 eq / ton, more preferably 10 to 80 eq / ton.

[0068] The Shore D hardness of the polyester elastomer is preferably 25 to 75, more preferably 25 to 65.

[0069] As a polycarbonate resin, there are no particular restrictions as long as the resin is composed of carbonate units and diol units. For example, aromatic polycarbonate resins with carbonate units and aromatic diol units as structural units, aliphatic polycarbonate resins with carbonate units and aliphatic diol units as structural units, and aromatic-aliphatic polycarbonate resins with carbonate units, aromatic diol units and aliphatic diol units as structural units can be cited.

[0070] As an aromatic diol constituting a polycarbonate resin, the aforementioned compounds can be exemplified as aromatic diols described as structural units of polyester resins.

[0071] As aliphatic diols constituting polycarbonate resins, examples can be the same aliphatic diols described as structural units of aliphatic polycarbonate that constitute soft segments of polyester elastomers.

[0072] The aforementioned polyamide resin refers to a resin obtained primarily from amino acids, lactams, and any one of diamines and dicarboxylic acids. Polyamide resins are obtained by polycondensation of amino acids, ring-opening polymerization of lactams, or polycondensation of diamines and dicarboxylic acids. In the raw materials constituting the polyamide resin, the amounts of amino acids, lactams, and diamines and dicarboxylic acids are preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more.

[0073] Examples of the aforementioned amino acids include amino aliphatic carboxylic acids with approximately 4 to 15 carbon atoms, such as 6-aminohexanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid; amino aromatic carboxylic acids, such as p-aminomethylbenzoic acid; etc.

[0074] Examples of the aforementioned lactams include aliphatic lactams with approximately 5 to 15 carbon atoms, such as ε-caprolactam and ω-laurolactam.

[0075] Examples of diamines mentioned above include tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, 2,4-dimethyloctamethylenediamine, m-phenylenediamine, p-phenylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 3,8-bis(aminomethyl)tricyclodecane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, and bis(aminopropyl)piperazine.

[0076] Examples of dicarboxylic acids mentioned above include adipic acid, octanoic acid, azelaic acid, sebacic acid, dodecanoic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, sodium isophthalate-5-sulfonate, hexahydroterephthalic acid, hexahydroisophthalic acid, and diethylene glycol.

[0077] As polyamide resins, examples include polyamide 6, polyamide 66, polyamide 46, polyamide 11, polyamide 12, polyamide 610, polyamide 69, polyamide 6T, polyamide 9T, polyamide MXD6, polyamide 6 / 66 copolymer, polyamide 6 / 610 copolymer, polyamide 6 / 6T copolymer, polyamide 6 / 66 / 610 copolymer, polyamide 6 / 12 copolymer, polyamide 6T / 12 copolymer, polyamide 6T / 66 copolymer, polyamide 6 / 6I copolymer, polyamide 66 / 6I / 6 copolymer, polyamide 6T / 6I copolymer, polyamide 6T / 6I / 66 copolymer, polyamide 6 / 66 / 610 / 12 copolymer, and polyamide 6T / M-5T copolymer. From the viewpoint of achieving a good balance of chemical resistance, impact resistance, and flowability in the obtained molded article, at least one of the following is preferred: polyamide 6, polyamide 66, polyamide 12, and copolymers thereof as the main component; more preferably, at least one of the following is preferred: polyamide 6 and copolymers thereof as the main component. It should be noted that, in this specification, "copolymer with A as the main component" refers to a copolymer having a structure derived from A, preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more.

[0078] The relative viscosity of the polyamide resin, when measured in 98% sulfuric acid solution (polyamide resin concentration 1 g / dl, temperature 20°C), is preferably 1.5 to 3.5, more preferably 2.0 to 3.0, and even more preferably 2.2 to 2.8.

[0079] There are no particular restrictions on the use of polyphenylene sulfide resins; commonly used polyphenylene sulfide resins can be used, such as poly(p-phenylene sulfide), polyphenylene sulfide sulfone, polyphenylene sulfide ketone, and polyphenylene sulfide ether.

[0080] Specifically, polyolefin resins can be categorized as homopolymers or copolymers whose main components are repeating units derived from α-olefins such as ethylene and propylene. Examples include homopolymers of propylene, homopolymers of ethylene, and block or random copolymers formed by copolymerizing ethylene with other α-olefins (e.g., propylene, 1-butene). One or more of these can be used within the range that contributes to the properties of the resin material. The polyolefin resin used in this invention can be either linear or branched. Preferably, the polyolefin resin is selected from at least one of the groups consisting of polyethylene resins whose main components are structural units derived from ethylene and polypropylene resins whose main components are structural units derived from propylene. As the polypropylene resin, any polypropylene resin such as isotactic, isotactic, or syndiotactic can be used. In addition, examples of the polyethylene resin include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), ultra-low-density polyethylene (ULDPE), and ultra-high molecular weight polyethylene (UHMW-PE).

[0081] The melting point of component (A) is preferably 100°C or higher, more preferably 150°C or higher, and even more preferably 300°C or lower, more preferably 260°C or lower. That is, the melting point of component (A) is preferably 100 to 300°C, more preferably 150 to 260°C. The melting point of component (A) can be determined by the measurement method described in the examples below.

[0082] The moisture content of component (A) is, for example, 200 ppm or less, preferably 170 ppm or less, and more preferably 150 ppm or less. It should be noted that the moisture content of component (A) can be adjusted to the above range by heating and drying component (A) or the like.

[0083] It should be noted that when component (A) contains two or more thermoplastic resins and / or thermoplastic elastomers, multiple melting points are sometimes observed. In this case, the melting point of component (A) can be determined as follows.

[0084] That is, when a component (A) contains two or more thermoplastic resins and / or thermoplastic elastomers with multiple melting points, and the difference between the maximum and minimum melting points is within 30°C, the melting point of component (A) is its weighted average. For example, in the case of component (A) containing 50% by mass of thermoplastic resin or thermoplastic elastomer a with a melting point of 100°C, 40% by mass of thermoplastic resin or thermoplastic elastomer b with a melting point of 110°C, and 10% by mass of thermoplastic resin or thermoplastic elastomer c with a melting point of 130°C, the melting point of component (A) is 100°C × 50% + 110°C × 40% + 130°C × 10% = 107°C.

[0085] In addition, if there are two or more thermoplastic resins and / or thermoplastic elastomers with multiple melting points, and the difference between the maximum and minimum values ​​of the multiple melting points exceeds 30°C, the highest melting point shall be taken as the melting point of component (A).

[0086] [(B) Component]

[0087] The electromagnetic wave shielding composition of the present invention contains soft magnetic metal powder as component (B). This allows the obtained molded article to be endowed with electromagnetic wave shielding properties. As component (B), conventionally known soft magnetic metal powders can be used, such as ferrous metal, alloys of iron with other elements (hereinafter sometimes referred to as iron-based alloys), and iron-containing compounds (preferably compounds containing ionic iron).

[0088] Iron powder can be used as the aforementioned ferrous metal. Pure iron is preferred.

[0089] As for the aforementioned iron-based alloys, depending on the intended use, alloys of iron with other metallic elements or iron with non-metallic elements can be used. Specifically, iron-based alloys, if expressed in terms of iron and the main constituent elements, can include Fe-C alloys, Fe-Cr alloys, Fe-Cr-Mo alloys, Fe-Cr-Al alloys, Fe-Si-Cr alloys, Fe-Mn alloys, Fe-Mn-Mo alloys, Fe-Ni alloys, Fe-Ni-Cr alloys, Fe-Ni-Co alloys, Fe-Co alloys, Fe-Si alloys, and Fe-Si-Al alloys, etc. It should be noted that Fe-Cr-Mo alloys refer to alloys in which the content of each component is in the order of Fe > Cr > Mo; the same applies to other alloys. The iron concentration in the iron-based alloy is, for example, 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more.

[0090] As the aforementioned iron-containing compounds, compounds containing divalent or trivalent iron (ionic iron), such as iron oxides, iron hydroxides, iron chlorides, iron sulfides, and iron sulfates, can be used.

[0091] From the viewpoint of further improving electromagnetic wave shielding performance, as component (B), it is preferably at least one powder selected from the group consisting of Fe-Si alloys, Fe-Si-Al alloys, Fe-Si-Cr alloys and ferrites, more preferably at least one powder selected from the group consisting of Fe-Si-Al alloys, Fe-Si-Cr alloys and ferrites, and even more preferably powders of Fe-Si-Al alloys and / or Fe-Si-Cr alloys.

[0092] The aforementioned Fe-Si alloys refer to Fe-based alloys containing Si. The preferred composition of Fe-Si alloys is 3-7% by mass of Si, with the remainder being substantially Fe.

[0093] The aforementioned Fe-Si-Al alloy is a Fe-based alloy containing Si and Al. Preferably, the Fe-Si-Al alloy contains Si and Al, with the remainder being substantially Fe. The preferred Si content in the Fe-Si-Al alloy is 3 to 12% by mass. Furthermore, the preferred Al content is 4 to 12% by mass. That is, the composition of the Fe-Si-Al alloy is particularly preferably characterized by a Si content of 3 to 12% by mass, an Al content of 4 to 12% by mass, and the remainder being substantially Fe. A representative example of the composition of a Fe-Si-Al alloy is Fe... 85 Si 10 Al5, Fe 84.5 Si 9.5 Al 5.5 wait.

[0094] The aforementioned Fe-Si-Cr alloys refer to Fe-based alloys containing Si and Cr. Preferably, the Fe-Si-Cr alloys contain Si and Cr, with the remainder being substantially Fe. The Si content in the Fe-Si-Cr alloys is preferably 10 to 25% by mass, more preferably more than 10% by mass and less than 25% by mass. Furthermore, the Cr content in the Fe-Si-Cr alloys is preferably 5% by mass and less, more preferably 0.5% to 5% by mass. That is, the composition of the Fe-Si-Cr alloys is particularly preferably characterized by a Si content of 10 to 25% by mass (preferably more than 10% by mass and less than 25% by mass), a Cr content of 5% by mass and less (preferably 0.5% to 5% by mass), and the remainder being substantially Fe.

[0095] As the aforementioned ferrite, known soft magnetic ferrites exhibiting soft magnetism can be used, among which Mn-Zn ferrites, Ni-Zn ferrites, Mg-Zn ferrites, Cu-Zn ferrites are preferred, and Mn-Zn ferrites are more preferred.

[0096] (B) Components can be used alone or in combination of two or more.

[0097] The average particle size D50 of component (B) is, for example, 1 μm or more, preferably 10 μm or more. By adjusting D50 to the above range, the electromagnetic wave shielding performance becomes better. Furthermore, the average particle size D50 of component (B) is, for example, 100 μm or less, preferably 70 μm or less. By adjusting D50 to the above range, the flowability of the electromagnetic wave shielding composition can be further improved, and the appearance of the resulting injection-molded article can be improved. That is, the average particle size D50 of component (B) is, for example, 1 to 100 μm, preferably 10 to 70 μm. It should be noted that the average particle size D50 in this invention represents the particle size at which the cumulative volume reference of the particle size becomes 50%.

[0098] (B) The shape of the component is not particularly limited and can be any of the following: spherical, flat, or amorphous. From the point of view of further improving the electromagnetic wave shielding performance at low frequencies, a flat shape is preferred.

[0099] The mass ratio ((A) component / (B) component) of the electromagnetic wave shielding composition of the present invention is 5 / 95 to 95 / 5, preferably 20 / 80 to 90 / 10, and more preferably 25 / 75 to 90 / 10. A higher content of component (B) further improves the electromagnetic wave shielding performance; however, if the amount is excessive, it may sometimes fail to adequately contain component (A), resulting in decreased flowability and mechanical properties. By adjusting the mass ratio of component (A) to component (B) to the above range, the electromagnetic wave shielding performance can be improved, and the aforementioned problems can be avoided.

[0100] It should be noted that in the electromagnetic wave shielding composition of the present invention, the amount (addition ratio) of the raw material component directly becomes the content (content ratio) in the electromagnetic wave shielding composition and the content (content ratio) in the molded article.

[0101] [(C) Component]

[0102] The electromagnetic wave shielding composition of the present invention, in addition to components (A) and (B) described above, also includes at least one selected from phosphite compounds and phosphate compounds as component (C). This allows for the suppression of increased fluidity during heating while maintaining electromagnetic wave shielding performance. As for component (C), any phosphite compound and / or phosphate compound can be used without particular limitation.

[0103] As a phosphite compound (also known as a phosphite ester compound), it contains one or more phosphorus atoms with three linkages, and each phosphorus atom is associated with s -OH groups and t -OR groups.a Base, u-OR b -base(-OR) b In the - radical, it is bonded to the phosphorus atom through -O-. R b A compound bonded by other -O- atoms (bonded with other phosphorus atoms). Wherein, s + t + u = 3, t is 1 or more, and u is 0 when there is 1 phosphorus atom in the molecule of phosphite compound 1, and 1 or 2 when there are 2 or more phosphorus atoms. When there are 2 or more phosphorus atoms, s, t, and u can vary depending on the number of phosphorus atoms, but are preferably the same. s is preferably 0. Furthermore, the number of phosphorus atoms in the molecule of phosphite compound 1 is preferably 1 to 4, more preferably 1 or 2, and particularly preferably 2.

[0104] As R a Examples of R that can be cited later can be found. 1 ~R 3 The same group, in phosphite compounds containing multiple R groups a In this case, they can be different from each other, but it is preferable that they are the same.

[0105] As R b Examples include hydrocarbon groups with 1 to 20 carbon atoms, preferably 2 to 6 valences, and more preferably 2 to 4 valences. b All the bonds between the phosphorus atoms are connected by -O- atoms. As a component of R... b Examples of hydrocarbon groups that can be represented include groups composed of aliphatic hydrocarbon groups, aromatic hydrocarbon groups, groups composed of aliphatic hydrocarbon groups and aromatic hydrocarbon groups, and groups composed of two or more aromatic hydrocarbon groups.

[0106] As a phosphite compound (also known as a phosphite compound), the aforementioned compound with s=0 (a complete ester compound) is preferred, especially more preferably at least one of the compounds selected from the group consisting of compounds shown in formulas (C1-1) to (C1-3) below, and even more preferably the compound shown in formula (C1-1) below and / or the compound shown in formula (C1-2) below.

[0107]

[0108] [In the formula, R] 1 ~R 3 Each can independently represent an aliphatic hydrocarbon group with 1 to 30 carbon atoms or an aromatic hydrocarbon group with 6 to 30 carbon atoms.

[0109] In equation (C1-1), multiple R 1 They can be the same or different, but the same is preferred. In formula (C1-2), multiple R... 2 They can be the same or different, but the same is preferred. In formula (C1-3), multiple R... 3 They can be the same or different, but the same is preferred.

[0110] By R 1 ~R 3 The aliphatic hydrocarbon group represented preferably has 2 to 25 carbon atoms, more preferably 8 to 23, and even more preferably 12 to 20.

[0111] By R 1 ~R 3 The aliphatic hydrocarbon group can be chain-like or cyclic, and can be saturated or unsaturated, preferably saturated aliphatic hydrocarbon group, and more preferably saturated chain aliphatic hydrocarbon group (i.e., alkyl group). Additionally, R... 1 ~R 3 The aliphatic hydrocarbon groups shown can be linear or branched, preferably linear. Examples of the aforementioned aliphatic hydrocarbon groups include saturated chain aliphatic hydrocarbon groups (i.e., alkyl groups) such as methyl, ethyl, n-propyl, n-butyl, 2-ethylhexyl, n-dodecyl, isotriadecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, n-eicosyl, and tetradecyl; and unsaturated aliphatic hydrocarbon groups such as vinyl, propenyl, butenyl, dodecenyl, tetradecenyl, hexadecenyl, octadecenyl, and eicosenyl.

[0112] By R 1 ~R 3 The aromatic hydrocarbon group represented preferably has 6 to 25 carbon atoms, more preferably 7 to 23, and even more preferably 10 to 20.

[0113] As a result of R 1 ~R 3 Examples of aromatic hydrocarbon groups include aryl groups such as phenyl and naphthyl; and alkylaryl groups with 1 to 5 alkyl groups having 1 to 4 carbon atoms bonded to them.

[0114] From the perspective of further improving the suppression effect of increased fluidity during heating, R 1 ~R 3 Preferably, it is an aromatic hydrocarbon group with 6 to 30 carbon atoms, more preferably an aromatic hydrocarbon group with 6 to 20 carbon atoms, and even more preferably a phenyl group or a group having 1 to 5 alkyl groups with 1 to 4 carbon atoms bonded to a phenyl group.

[0115] Especially in R 1 In the case of an aromatic hydrocarbon group, this R 1 Preferably, it is a phenyl group or a group having 1 to 3 alkyl groups having 1 to 4 carbon atoms bonded to the phenyl group.

[0116] Additionally, in R 2 and R 3 In the case of an aromatic hydrocarbon group, this R 2 and R 3Preferably, the phenyl group has 1 to 5 alkyl groups having 1 to 4 carbon atoms bonded to it, more preferably, it has at least 1 to 3 tert-butyl groups bonded to it. The bonding position of the alkyl groups having 1 to 4 carbon atoms bonded to the phenyl group is not particularly limited, but preferably it is bonded to any position among the 2, 2, 4, 2, 6, and 2, 4, 6 positions relative to the -OP linking bond of the phenyl group. Among these, the following are preferred: phenyl groups having a tert-butyl group bonded to the 2 position and alkyl groups having 1 to 3 carbon atoms bonded to the 4 and 6 positions; phenyl groups having a tert-butyl group bonded to the 2 and 6 positions and alkyl groups having 1 to 3 carbon atoms bonded to the 4 position; and phenyl groups having a tert-butyl group bonded to the 2, 4, and 6 positions.

[0117] Specific examples of phosphite compounds include triphenyl phosphite, tri(p-tolyl) phosphite, tri(4-tert-butylphenyl) phosphite, trinonylphenyl phosphite, trilauryl phosphite, trioleinyl phosphite, diphenyl mono(2-ethylhexyl) phosphite, tristearyl phosphite, and tri(2,4-di-tert-butylphenyl) phosphite, as shown in formula (C1-1); bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, and distearyl pentaerythritol diphosphite, as shown in formula (C1-2); and tetra(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, as shown in formula (C1-3).

[0118] Examples of phosphate ester compounds (also known as phosphoric acid ester compounds) include one or more P=O atoms with three bonds on the phosphorus atom, and each P=O atom is associated with s -OH groups and t -OR groups. a base and u-OR b -base(-OR) b In the - radical, the phosphorus atom of P=O is bonded to -O-. b A compound bonded by other -O- atoms to other P=O phosphorus atoms. Wherein, s + t + u = 3, t is 1 or more, and u is 0 when there is one P=O atom, and 1 or 2 when there are two or more P=O atoms. When there are two or more P=O atoms, s, t, and u can vary depending on the P=O atom, but are preferably the same. s is preferably 1 or 2. R a 、R b Same as above. It should be noted that the number of P=O in the molecule of phosphate ester compound 1 is preferably 1 or 2, more preferably 1.

[0119] As a phosphate ester compound, the preferred compound is the one shown in the following formula (C2).

[0120]

[0121] In equation (C2), s1 represents an integer from 0 to 2, t1 represents an integer from 1 to 3, and R a Same as above. Wherein, s1 + t1 = 3.

[0122] In equation (C2) there are multiple R a In this case, they can be the same or different, but it is preferred that they be the same.

[0123] s1 is preferably 1 or 2.

[0124] As the compound represented by formula (C2), it can be R a All are compounds with aromatic hydrocarbon groups having 6 to 30 carbon atoms (hereinafter, sometimes referred to as aromatic phosphate ester compounds), and may also be R a All are compounds with aliphatic hydrocarbon groups having 1 to 30 carbon atoms (hereinafter sometimes referred to as aliphatic phosphate ester compounds), preferably aliphatic phosphate ester compounds, more preferably compounds with s1 of 1 or 2 (acid compounds), further preferably compounds shown in the following formula (C2-1), and particularly preferably compounds shown in the following formula (C2-2).

[0125]

[0126] In formula (C2-1), R 4 It is an aliphatic hydrocarbon group with 1 to 30 carbon atoms, where n is 1 or 2.

[0127]

[0128] In formula (C2-2), R 5 It is an alkyl group having 1 to 30 carbon atoms, where n is 1 or 2.

[0129] In equation (C2-1), when there are multiple R... 4 In the case of multiple R 4 They can be the same or different, but the same is preferred. In equation (C2-2), when there are multiple R... 5 In the case of multiple R 5 They can be the same or different, but the same is preferred.

[0130] By R 4 The aliphatic hydrocarbon group represented preferably has 1 to 25 carbon atoms, more preferably 2 to 23, and even more preferably 2 to 20. In particular, by using R... 4 Phosphate ester compounds with aliphatic hydrocarbon groups having 8–23 or 12–20 carbon atoms exhibit even better suppression of fluidity increase upon heating. In formula (C2-1), R 4The content of the phosphate ester compound having an aliphatic hydrocarbon group having 8 to 23 carbons (preferably 12 to 20 carbons) is preferably 20% by mass or more, more preferably 40% by mass or more, further preferably 50% by mass or more, particularly preferably 80% by mass or more, and can be 100% by mass.

[0131] By R 5 The alkyl group represented preferably has 1 to 25 carbon atoms, more preferably 2 to 23, and even more preferably 2 to 20. In particular, by using R... 5 These are phosphate ester compounds with alkyl groups having 8–23 or 12–20 carbon atoms, and their ability to suppress fluidity increase upon heating becomes even more excellent. In formula (C2-2), R 5 The content of alkyl phosphate compounds having carbon numbers of 8 to 23 (preferably 12 to 20) is preferably 20% by mass or more, more preferably 40% by mass or more, further preferably 50% by mass or more, particularly preferably 80% by mass or more, and can be 100% by mass.

[0132] As a result of R 4 The aliphatic hydrocarbon group represented can be exemplified by those derived from R. 1 ~R 3 The aliphatic hydrocarbon group represented is the same group as the one described, wherein a straight-chain aliphatic hydrocarbon group is preferred, and a straight-chain saturated aliphatic hydrocarbon group is more preferred.

[0133] As a result of R 5 The aliphatic hydrocarbon group represented can be exemplified by R. 1 ~R 3 The alkyl group in the text is the same as the group that is indicated by the alkyl group.

[0134] In formulas (C2-1) and (C2-2), n can be 1 or 2, or a mixture of a compound with n=1 and a compound with n=2 can be used.

[0135] Specifically, examples of phosphate ester compounds include: mono- or di-methyl phosphates, mono- or di-ethyl phosphates, mono- or di-butyl phosphates, mono- or di-2-ethylhexyl phosphates, mono- or di-isotridecyl phosphates, mono- or di-lauryl phosphates, mono- or di-stearyl phosphates, mono- or di-oleoyl phosphates, and mono- or di-tetracosyl phosphates. These phosphate ester compounds can be used alone or in combination of two or more. Preferably, the phosphate ester compound is selected from at least one of the group consisting of mono-ethyl phosphates, di-ethyl phosphates, mono-stearyl phosphates, and di-stearyl phosphates.

[0136] As phosphate ester compounds, commercially available products can be used, such as LBT-1830 and LBT-1813 manufactured by Sakai Chemical Industry Co., Ltd., JP-502, JP-513 and JP-524R manufactured by Johoku Chemical Industry Co., Ltd., and ADK STAB AX-71 manufactured by ADEKA CORPORATION.

[0137] As component (C), one type can be used alone, or two or more types can be used in combination.

[0138] As component (C), a phosphate ester compound is preferred.

[0139] Furthermore, as component (C), it is preferably at least one selected from the compounds shown in formula (C1-1), formula (C1-2), and formula (C2-1). By using such a compound, the suppression of fluidity increase during heating becomes more excellent. From the viewpoint of further improving the suppression effect of fluidity increase during heating, as component (C), it is preferably selected from R in formula (C1-1). 1 Phosphite compounds consisting of aromatic hydrocarbon groups having 6 to 30 carbon atoms, and R in the aforementioned (C1-2) 2 At least one of an aromatic hydrocarbon group having 6 to 30 carbon atoms and a phosphate group represented by the aforementioned formula (C2-2). The detailed mechanism is unclear, but it is presumed to affect the surface coating of component (B).

[0140] In this invention, relative to a total of 100 parts by mass of components (A) and (B), the content of component (C) is 0.02 to 1.4 parts by mass, preferably 0.03 to 1.2 parts by mass, more preferably 0.05 to 1.0 parts by mass, and even more preferably 0.1 to 0.6 parts by mass. It is believed that component (C) acts as a surface coating for component (B). The detailed mechanism is not yet clear, but it is believed that this is achieved by having component (C) containing P-OH and P-OR. a POR b With a structure like P=O, component (C) readily coordinates on the surface of component (B), tending to easily form the surface coating. Furthermore, it is believed that by forming such a surface coating, the effects of improved dispersibility of component (B) and the inhibition of resin or elastomer degradation behavior by component (B) can be observed. Therefore, improved thermal stability and retention stability of the electromagnetic shielding composition of the present invention can be observed. When the content is less than 0.02 parts by mass, the desired properties are difficult to obtain; conversely, when it is more than 1.4 parts by mass, component (C) acts as a plasticizer, causing poor flowability upon heating, which is therefore undesirable.

[0141] In addition, relative to 100 parts by mass of component (B), the content of component (C) is, for example, 0.05 to 2.7 parts by mass, preferably 0.1 to 2.0 parts by mass, more preferably 0.3 to 1.2 parts by mass, and even more preferably 0.4 to 1.0 parts by mass.

[0142] The total content of components (A), (B), and (C) in the electromagnetic wave shielding composition of the present invention is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and can be 100% by mass or less, or 99.5% by mass or less.

[0143] [Other ingredients]

[0144] The electromagnetic shielding composition of the present invention may also contain various additives such as antioxidants, heat stabilizers, ultraviolet absorbers, antistatic agents, dyes, pigments, lubricants, plasticizers, release agents, crystallization promoters, crystallization nucleating agents, and epoxy compounds, depending on its intended purpose. When the total amount of the aforementioned components (A) and (B) is set to 100 parts by mass, the total amount of these various additives is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 2 parts by mass or less.

[0145] As the aforementioned antioxidants, hindered phenolic antioxidants are preferred. Specifically, examples include: 3,5-di-tert-butyl-4-hydroxytoluene, n-octadecyl-β-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, tetra[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, and 1,3,5-trimethyl-2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate. '-Hydroxybenzyl)benzene, (3,5-di-tert-butyl-4-hydroxybenzyl phosphate monoethyl ester)calcium, triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 3,9-bis[1,1-dimethyl-2-{β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, bis[3,3-bis(4'- [Hydroxy-3'-tert-butylphenyl)butyrate]diol ester, 2,2'-ethylidene bis(4,6-di-tert-butylphenol), N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 2,2'-oxamidobis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-S-triazine-2 The antioxidants include 4,6(1H,3H,5H)-trione, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid and the ester of -1,3,5-tris(2-hydroxyethyl)-S-triazine-2,4,6(1H,3H,5H), N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide), etc. These antioxidants can be used alone or in mixtures. When the total of the aforementioned components (A) and (B) is set to 100 parts by mass, the amount of antioxidant is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less. In addition, the amount of antioxidant can be 0.05 parts by mass or more, or 0.1 parts by mass or more. That is, when the total of the aforementioned components (A) and (B) is set to 100 parts by mass, the amount of antioxidant is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.1 to 1 parts by mass.

[0146] Examples of release agents include long-chain fatty acids or their esters, metal salts, amide compounds, polyethylene wax, silicone, and polyethylene oxide. Long-chain fatty acids with 12 or more carbon atoms are particularly preferred; examples include stearic acid, 12-hydroxystearic acid, benzyl acid, and linalic acid. Some or all of the carboxylic acid can be esterified by monoethylene glycol or polyethylene glycol, or a metal salt can be formed. Amide compounds include ethylene bis(terephthalamide) and methylene bis(stearamide). These release agents can be used alone or in mixtures. When the total of components (A) and (B) is set to 100 parts by mass, the amount of release agent is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less. Alternatively, the amount of release agent can be 0.1 parts by mass or more, or 0.3 parts by mass or more. That is, when the total of the aforementioned components (A) and (B) is set to 100 parts by mass, the amount of the release agent is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, and even more preferably 0.3 to 1 part by mass.

[0147] The electromagnetic wave shielding composition of the present invention generally does not contain any components other than those described above (e.g., thermosetting resin, fiber components such as glass fiber, etc.), but may contain them as needed. For example, the thermosetting resin may be set to 0.2% by mass or less in the electromagnetic wave shielding composition of the present invention, and the fiber component may be set to 4% by mass or less in the electromagnetic wave shielding composition of the present invention.

[0148] The method for manufacturing the electromagnetic wave shielding composition of the present invention is not particularly limited. For example, it can be obtained by dry mixing components (A), (B), and (C), and other components as needed, followed by melt mixing using a single-screw or twin-screw screw-type melt mixer, or a conventional thermoplastic resin or thermoplastic elastomer mixer, such as a kneading heater. Granulation can then be performed as needed via a granulation process. Alternatively, if necessary, component (B) can be pretreated (mixed) with component (C) before being mixed with component (A).

[0149] The electromagnetic wave shielding composition of the present invention exhibits excellent mass production properties due to its suppression of increased fluidity upon heating. The ΔMFR of the electromagnetic wave shielding composition of the present invention, determined according to ISO 1133 and calculated by the following formula, is preferably 20 g / 10 min or less, more preferably 15 g / 10 min or less, and may also be 10 g / 10 min or less. The lower limit of the ΔMFR of the electromagnetic wave shielding composition of the present invention is not particularly limited and may be 1 g / 10 min or more. It should be noted that the ΔMFR can be measured according to the method shown in the examples described later.

[0150] ΔMFR = (MFR at 25 minutes of stay) - (MFR at 5 minutes of stay)

[0151] (In the formula, the MFR at 25 minutes of residence is the melt flow rate measured with the preheating time set to 25 minutes, and the MFR at 5 minutes of residence is the melt flow rate measured with the preheating time set to 5 minutes. It should be noted that the load for measuring the melt flow rate is 2160g, and the measurement temperature is the melting point of component (A) + 25℃.)

[0152] When manufacturing molded articles from the electromagnetic wave shielding composition of the present invention, the molding method of the electromagnetic wave shielding composition is not particularly limited, and injection molding, extrusion molding, compression molding, blow molding, etc., can be performed. From the perspective of the high degree of freedom in the shape of the resulting molded article, injection molding is preferred. Furthermore, the excellent thermal stability and retention stability (i.e., the inhibition of fluidity increase during heating) of the electromagnetic wave shielding composition of the present invention are easily exerted during injection molding, therefore, injection molding is preferred.

[0153] The molded article manufactured from the electromagnetic wave shielding composition of the present invention is characterized in that it contains the aforementioned component (A) and component (B) in a mass ratio ((A) component / (B) component) ranging from 5 / 95 to 95 / 5, and further contains the aforementioned component (C) in an amount of 0.02 to 1.4 parts by mass relative to a total of 100 parts by mass of the aforementioned component (A) and component (B). When the article is made to a thickness of 2.0 mm, the magnetic field shielding performance measured by the KEC method is 3 dB or more at both frequencies of 1 MHz and 10 MHz. Furthermore, the molded article may contain the various additives described above as other components. The preferred methods for the types and amounts of each component contained in the molded article are the same as described above. Additionally, the magnetic field shielding performance measured by the KEC method when the thickness of the molded article is 2.0 mm is preferably 5 dB or more at both frequencies of 1 MHz and 10 MHz, more preferably 8 dB or more, and the upper limit is not particularly limited, for example, 40 dB.

[0154] As described above, the electromagnetic wave shielding composition of the present invention is preferably used for injection molding, that is, the molded article manufactured from the electromagnetic wave shielding composition of the present invention preferably has gate marks. It should be noted that "gate marks" refer to marks such as unevenness formed during the manufacture of the molded article by injection molding due to the gate used for the injection composition.

[0155] The shape of the molded article is not particularly limited, and it can be formed into a shape (flat plate, tube, shell, etc.) appropriate to the application, as well as in terms of thickness and size. The thickness of the molded article is, for example, 0.1 to 10 mm, preferably 0.3 to 5 mm.

[0156] The molded article obtained from the electromagnetic wave shielding composition of the present invention has electromagnetic wave shielding performance. As a method for evaluating electromagnetic wave shielding performance, the KEC method developed by the Kansai Electronics Industry Promotion Center (KEC) is known. This KEC method measures the shielding effect of electromagnetic waves generated in the near field, separating the electric field component and the magnetic field component. It utilizes a sheet-like test sample to receive electromagnetic waves transmitted from a transmitting antenna (transmitting fixture) using a receiving antenna (receiving fixture), measures the attenuated electromagnetic waves, and quantifies them as the attenuation rate (measured in dB), thereby providing an evaluation. In the present invention, under room temperature conditions, using a sample of a certain thickness (2.0 mm) obtained by molding the electromagnetic wave shielding composition, the attenuation rate of the magnetic field component is measured in the frequency range of 0.1 MHz to 1000 MHz. The attenuation rates at 1 MHz and 10 MHz, which are important in the present invention, are confirmed. Specifically, the measurement can be performed according to the method shown in the examples described later.

[0157] A molded article (e.g., a sheet) with a thickness of 2.0 mm obtained by molding the electromagnetic wave shielding composition of the present invention, when measured using the KEC method, exhibits a magnetic field shielding performance (attenuation rate) of 3 dB or more at frequencies of 1 MHz and 10 MHz. The shielding performance (attenuation rate) is preferably 5 dB or more, more preferably 8 dB or more, and the upper limit is not particularly limited, for example, 40 dB.

[0158] The electromagnetic wave shielding composition of the present invention yields molded articles exhibiting electromagnetic wave shielding performance at low frequencies, such as 1 kHz to 1 GHz (preferably 10 kHz to 100 MHz, more preferably 0.1 MHz to 100 MHz). That is, the electromagnetic wave shielding composition of the present invention can be used to shield low-frequency electromagnetic waves, and is suitable for molding low-frequency electromagnetic wave shields. Specifically, it can be used in devices mounted in various electronic devices, around power conversion equipment in electric vehicles, and in housings, resin or elastomer molded articles, etc., around data processing devices such as cameras and radio waves.

[0159] This application claims priority based on Japanese Patent Application No. 2023-035389, filed on March 8, 2023. The entire contents of the description in Japanese Patent Application No. 2023-035389, filed on March 8, 2023, are incorporated herein by reference.

[0160] Example

[0161] The present invention will be described in more detail below with reference to specific embodiments, but the present invention is not limited to these embodiments.

[0162] <Examples 1-15 and Comparative Examples 1-9>

[0163] In Examples 1-15 and Comparative Examples 1-9, the following materials were used as components of the electromagnetic wave shielding composition.

[0164] [(A) ingredient]

[0165] A-1: Polybutylene terephthalate, melting point 225℃, resin drying temperature 130℃ (manufactured by Toyobo Co., Ltd., intrinsic viscosity = 0.83 dl / g)

[0166] A-2: Polybutylene terephthalate, melting point 225℃, resin drying temperature 130℃ (manufactured by Toyobo Co., Ltd., intrinsic viscosity = 1.32 dl / g).

[0167] A-3: Polyester elastomer, melting point 205℃, resin drying temperature 100℃

[0168] A copolymer with a PBT / HPCD ratio of 70 / 30 (mass%) (PELPRENE manufactured by Toyobo Co., Ltd. (registered trademark), specific viscosity: 1.20 dl / g, Shore D hardness: 60)

[0169] Polyester elastomer (A-3) was manufactured by the following method: 70 parts by weight of polybutylene terephthalate (PBT) with a number average molecular weight of 30,000 and 30 parts by weight of polycarbonate diol (HPCD) with a number average molecular weight of 10,000 and 1,6-hexanediol residues were stirred at 225°C–245°C and 130 Pa for 1 hour. An ester exchange reaction was carried out, and after confirming that the mixture became transparent, the contents were removed and cooled to obtain polyester elastomer (A-3).

[0170] A-4: Polyester elastomer, melting point 180℃, resin drying temperature 100℃

[0171] A polyester elastomer with terephthalic acid (TPA) / / 1,4-butanediol (BD) / polyoxytetramethylene glycol (PTMG: number average molecular weight 2000) of 100 / / 75 / 25 (mol%) (specific viscosity: 2.50 dl / g, acid value: 21 eq / ton, Shore D hardness: 31).

[0172] A-5: Polyamide 6, melting point 225℃, resin drying temperature 100℃ (manufactured by Toyobo Co., Ltd., relative viscosity = 2.2)

[0173] It should be noted that the melting point, intrinsic viscosity, specific viscosity, Shore D hardness, acid value, and relative viscosity mentioned above were determined by the following methods.

[0174] Melting point

[0175] Using a differential scanning calorimeter "DSC220" manufactured by Seiko Electronics Industries, 5 mg of sample was placed in an aluminum pot, the lid was pressed and sealed, and the temperature was increased from 20 °C to 270 °C in nitrogen at a rate of 10 °C / min. The melting point was determined from the endothermic peak based on melting in the obtained thermogram curve.

[0176] Intrinsic viscosity

[0177] Dissolve 0.1 g of the sample in 25 ml of a phenol / tetrachloroethane (6 / 4 mass ratio) mixture and measure the viscosity using an Ubbelohde viscometer at 30 °C. (Unit: dl / g)

[0178] Specific viscosity

[0179] Dissolve 0.05 g of the sample in 25 ml of a mixed solvent (phenol / tetrachloroethane = 60 / 40 (mass ratio)) and measure the viscosity using an Ostwald viscometer at 30 °C. (Unit: dl / g)

[0180] Shore D hardness

[0181] The test was conducted according to JIS K7215-1986. The test piece was made by overlapping three injection-molded parts (100 mm in length, 100 mm in width, and 2 mm in thickness) produced at a barrel temperature of 240 °C and a mold temperature of 50 °C. The hardness was measured using a hardness tester with a 5000 g indenter of type D. The value after 5 seconds of measurement was set as the D hardness (Shore D hardness).

[0182] <Acid Value>

[0183] Dissolve 0.5 g of the sample in 25 mL of benzyl alcohol and titrate using a 0.01 mol / L benzyl alcohol solution of sodium hydroxide. Use an indicator made by dissolving 0.10 g of phenolphthalein in a mixture of 50 mL of ethanol and 50 mL of water.

[0184] Relative viscosity

[0185] Dissolve 0.25 g of polyamide resin in 25 ml of 98% sulfuric acid. Place 10 ml of this sample solution into an Ostwald viscosity tube and measure the viscosity at 20°C. Separately, place another solvent (98% sulfuric acid) into an Ostwald viscosity tube and measure the viscosity at 20°C. Calculate the relative viscosity using the following formula.

[0186] RV = T / T0

[0187] RV: Relative viscosity, T: Fall time of sample solution, T0: Fall time of solvent

[0188] [(B) Component]

[0189] B-1: Fe-Si-Al alloy (average grain size D50: approx. 40 μm, shape: flat), manufactured by SANYO SPECIALSTEEL Co., Ltd. as "FME3D-AH"

[0190] B-2: Fe-Si-Cr alloy (average grain size D50: approx. 20 μm, shape: flat), manufactured by KINSEI MATEC CO.,LTD. under the brand name "JEMK".

[0191] B-3: Mn-Zn ferrite (average particle size D50: approximately 50 μm, shape: flat), manufactured by Powdertech as "MZ-05P050"

[0192] The average particle size D50 was calculated as follows: After adding ethanol and the powder sample to a beaker, disperse it using an ultrasonic cleaner for 30 seconds. Then, place it in the sample circulator chamber of a laser diffraction / scattering particle size distribution measuring device MT3300EXII (manufactured by Microtrac BEL) and measure the volume distribution for 120 seconds. The particle size at 50% of the measured volume distribution was taken as the average particle size D50.

[0193] [(C) Component]

[0194] C-1: ADEKACORPORATION manufactures "ADK STAB AX-71" (acidic stearyl phosphate, O=P(OC)). 18 H 37 O) n (OH) 3-n (n is 1 or 2)

[0195] C-2: "JP-502" manufactured by Johoku Chemical Industry Co., Ltd. (ethyl phosphate, O=P(C2H5O) n (OH) 3-n (n is 1 or 2)

[0196] C-3: "JP-360" (triphenyl phosphite) manufactured by Johoku Chemical Industry Co., Ltd.

[0197] C-4: PEP-36 (bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite) manufactured by Clariant.

[0198] [Other phosphorus compounds]

[0199] C-5: Clariant's "PEP-Q" (tetra(2,4-di-tert-butylphenyl)-4,4'-biphenyl diphosphonate) (a compound with the following formula)

[0200]

[0201] C-6: "JC-263" (triphenylphosphine) manufactured by Kitakita Chemical Industry Co., Ltd.

[0202] C-7: "Exolit OP 1240" (aluminum hypophosphite) manufactured by Clariant

[0203] Other additives

[0204] Antioxidant: IRGANOX1010 manufactured by BASF

[0205] Release agent: LICOWAX-OP manufactured by Clariant

[0206] The components shown in Table 1 were dry-blended at the ratio of the composition (parts by mass) shown in Table 1, and using a twin-screw extruder (STS-35 manufactured by COPERION), the barrel temperature was set at the melting point of each (A) component + 25°C, and melt-kneading was carried out under the conditions of a discharge rate of 20 kg / hr and a screw rotation speed of 180 rpm to produce pellets of the electromagnetic wave shielding composition. Using the obtained pellets, ΔMFR was measured by the method described below. In addition, using the obtained pellets, test pieces were produced by the method described below, and the electromagnetic wave shielding performance (dB) at 1 MHz and 10 MHz was measured. The measurement results of the electromagnetic wave shielding compositions of Examples 1 to 15 and Comparative Examples 1 to 9 are shown in Table 1.

[0207] <Magnetic field component shielding performance under the KEC method>

[0208] In order to measure the shielding performance of the magnetic field component, the production (molding) and measurement of test pieces were carried out according to the following steps.

[0209] Using an injection molding machine manufactured by TOSHIBA MACHINE CO., LTD, under the setting of a barrel temperature of the melting point of each (A) component + 25°C and a mold temperature of 50°C, a flat plate (sheet) with a shape of 150 mm × 150 mm × 2 mm (thickness) was molded by injection molding, and then the electromagnetic wave shielding performance was measured by the KEC method.

[0210] The electromagnetic wave shielding property (shielding property of the magnetic field component) of the aforementioned 2.0 mm thick sheet was measured by the KEC method. It was sandwiched between a pair of units for evaluating the magnetic field shielding effect and continuously varied from 0.1 MHz to 1000 MHz. In particular, the attenuation rate (relative value) calculated from the transmission / reception intensity values at 1 MHz and 10 MHz was adopted as the value representing the electromagnetic wave shielding property.

[0211] <Degree of increase in fluidity during heating (ΔMFR)>

[0212] The increase in fluidity of the electromagnetic wave shielding composition during heating was evaluated based on the results of melt flow rate measurements with different preheating times. In the following evaluation, the preheating time is considered as the heating time of the electromagnetic wave shielding composition.

[0213] Using a melt indexer (manufactured by Toyo Seiki Co., Ltd.), and granules with a moisture content of less than 200 ppm obtained by drying at the specified resin drying temperature corresponding to each component (A) for 3 hours, the MFR at a residence time of 25 minutes and the MFR at a residence time of 5 minutes were measured according to ISO 1133 under a load of 2160 g. It should be noted that the test temperature was set to the melting point of component (A) + 25°C (250°C for polybutylene terephthalate resins of A-1 and A-2, 230°C for polyester elastomers of A-3, 205°C for polyester elastomers of A-4, and 250°C for polyamide resins of A-5). The measured results were substituted into the following formula to calculate ΔMFR.

[0214] ΔMFR = (MFR at 25 minutes of stay) - (MFR at 5 minutes of stay)

[0215] (In the formula, MFR at 25 minutes refers to the melt flow rate measured according to the method of ISO 1133 with a preheating time of 25 minutes, and MFR at 5 minutes refers to the melt flow rate measured according to the method of ISO 1133 with a preheating time of 5 minutes.)

[0216] [Table 1]

[0217]

[0218] As shown in Table 1, the electromagnetic wave shielding compositions of Examples 1 to 15 of the present invention, by mixing soft magnetic metal powder as component (B) and at least one of phosphite-based compounds and / or phosphate-based compounds as component (C) in a specific range ratio to a thermoplastic resin or thermoplastic elastomer as component (A), achieve good electromagnetic wave shielding performance and suppress the increase in fluidity during heating (i.e., excellent thermal stability and retention stability). On the other hand, in Comparative Examples 1 to 9, the thermal stability and retention stability were poor, raising concerns about adverse effects on the appearance, mass production, etc., of the molded articles obtained from the electromagnetic wave shielding compositions.

[0219] Industrial availability

[0220] According to the present invention, the increase in fluidity during heating can be suppressed, and a resin- or elastomer-containing composition with excellent electromagnetic wave shielding performance can be obtained. Therefore, it is expected that components addressing electromagnetic wave noise issues can be manufactured with high production efficiency. In recent years, the number of noise-generating sources in automobiles has increased, and the impact of electromagnetic wave noise, especially low-frequency electromagnetic wave noise from radio waves, vehicle cameras, etc., is a major issue, and countermeasures are necessary. Therefore, by applying the electromagnetic wave shielding composition of the present invention, in addition to the weight reduction resulting from replacing metals, it is also expected that the degree of freedom in shape can be increased. Furthermore, by applying the electromagnetic wave shielding composition of the present invention, electromagnetic wave shielding performance can be imparted to housing materials that do not normally have noise reduction functions, thus enabling component manufacturing with higher safety, which can be considered a revolutionary material.

Claims

1. An electromagnetic wave shielding composition, characterized in that, The range of (A) component / (B) component (by mass ratio) from 5 / 95 to 95 / 5 includes at least one component selected from thermoplastic resins and thermoplastic elastomers, namely component (A), and soft magnetic metal powder, namely component (B). The compound further comprises at least one component (C) selected from phosphite compounds and phosphate compounds, in an amount of 0.02 to 1.4 parts by mass relative to a total of 100 parts by mass of components (A) and (B). When a 2.0 mm thick sheet formed from the composition was tested using the KEC method, it showed a magnetic field shielding performance of more than 3 dB at both 1 MHz and 10 MHz.

2. The electromagnetic wave shielding composition according to claim 1, characterized in that, Based on the ΔMFR determined according to ISO 1133 and calculated using the following formula, it is less than 20 g / 10 min. ΔMFR = (MFR at 25 minutes of stay) - (MFR at 5 minutes of stay) In the formula, the MFR at 25 minutes of residence is the melt flow rate measured with the preheating time set to 25 minutes, the MFR at 5 minutes of residence is the melt flow rate measured with the preheating time set to 5 minutes, and the load for measuring the melt flow rate is 2160g, and the measuring temperature is the melting point of component (A) + 25℃.

3. The electromagnetic wave shielding composition according to claim 1 or 2, characterized in that, The component (A) contains one or more selected from the group consisting of polyester resins, polyester elastomers, polycarbonate resins, polyamide resins, polyphenylene sulfide resins and polyolefin resins.

4. The electromagnetic wave shielding composition according to claim 1 or 2, characterized in that, The (B) component is at least one powder selected from the group consisting of Fe-Si alloys, Fe-Si-Al alloys, Fe-Si-Cr alloys and ferrites.

5. The electromagnetic wave shielding composition according to claim 1 or 2, characterized in that, The shape of component (B) is flat.

6. The electromagnetic wave shielding composition according to claim 1 or 2, wherein, The average particle size D50 of component (B) is 1–100 μm.

7. The electromagnetic wave shielding composition according to claim 1 or 2, characterized in that, The (C) component is selected from at least one of the compounds shown in formula (C1-1), formula (C1-2), and formula (C2-1). In equation (C1-1), R 1 This indicates an aliphatic hydrocarbon group with 1 to 30 carbon atoms or an aromatic hydrocarbon group with 6 to 30 carbon atoms. In equation (C1-2), R 2 This indicates an aliphatic hydrocarbon group with 1 to 30 carbon atoms or an aromatic hydrocarbon group with 6 to 30 carbon atoms. In equation (C2-1), R 4 It is an aliphatic hydrocarbon group with 1 to 30 carbon atoms, where n is 1 or 2.

8. The electromagnetic wave shielding composition according to claim 1 or 2, wherein, The content of component (C) is 0.05 to 2.7 parts by mass relative to 100 parts by mass of component (B).

9. A molded article formed from the electromagnetic wave shielding composition of claim 1 or 2.

10. Use of the electromagnetic wave shielding composition according to claim 1 or 2 for shielding electromagnetic waves with frequencies from 1 kHz to 1 GHz.

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