JP2010138398A - Electromagnetic wave-inhibiting resin composition and molded article - Google Patents

Abstract

A thermoplastic resin composition for suppressing electromagnetic waves, which has excellent conductivity, mechanical strength, heat resistance, chemical resistance and molding processability, and has excellent electromagnetic wave suppression particularly in a frequency range of about 2 to 2.5 GHz. Offer things.
The invention includes (A) an aromatic polycarbonate resin, (B) a polyester resin, and (C) carbon nanocoils, wherein (C) carbon nanocoils are present in a continuous phase formed of a resin component. An electromagnetic wave suppressing resin composition. An electromagnetic wave suppressing resin molded product obtained by injection molding of the electromagnetic wave suppressing resin composition. Chemical resistance is imparted by blending the polyester resin, and a good conductive network is formed by carbon nanocoils in the continuous phase of the resin component, and good electromagnetic wave suppression is obtained.
[Selection] Figure 1

Description

  The present invention relates to an electromagnetic wave suppressing resin composition and a molded product thereof. Specifically, an electromagnetic wave suppressing resin composition having excellent electrical conductivity, mechanical strength, heat resistance, chemical resistance, and molding processability, and an electromagnetic wave suppressing resin molding formed by injection molding the electromagnetic wave suppressing resin composition It is about goods.

  In recent years, with the rapid development of IT society, high-speed processing of electronic devices has progressed, and the operating frequency of ICs such as LSIs and microprocessors has increased. In the communication field, high-speed communication networks using optical fibers have been used, and the next generation 2GHz for multimedia mobile communications, 5.8GHz for ETS (automatic toll collection system) in the field of ITS (Intelligent Tranport System), driving support road system (AHS) that measures the distance between vehicles and informs the driver In the automobile-mounted radar, electromagnetic waves with a frequency of 76 GHz are used, and it is expected that the use range of high-frequency electromagnetic waves will be further expanded in the future. Electromagnetic waves tend to emit noise as the frequency increases. On the other hand, malfunctions occur due to deterioration in the noise environment inside electronic devices due to downsizing and high density of electronic devices. The adverse effects on the human body are also becoming a problem.

  Such an electromagnetic wave prevention material includes an electromagnetic wave blocking body and an electromagnetic wave suppressing body. A metal material is generally used for the electromagnetic wave shielding body. For example, a metal plate is used on the wall material of a room where precision equipment that dislikes electromagnetic waves is installed to prevent the electromagnetic wave from entering the room. Yes.

  On the other hand, the electromagnetic wave suppressor significantly attenuates the intensity of the transmitted or reflected electromagnetic wave by converting the incident electromagnetic wave into thermal energy. Conventionally, as an electromagnetic wave suppressing body for use in electronic equipment, a plastic casing formed by conducting a conductive treatment on the surface or mixing a conductive material with a resin is used from the viewpoint of freedom of shape and weight reduction. Yes. In addition, many materials that have been provided with electromagnetic wave suppression performance by affixing or forming a composite material sheet or coating film in which a conductive material powder is dispersed in a matrix of resin, rubber, paint, or the like, to a site where electromagnetic waves are to be suppressed are also used. It has been. As this conductive material, ferrite and graphite (for example, Patent Document 1) are mainly used.

  However, since ferrite has a large specific gravity, there is a drawback that the composite material blended with it becomes heavy, and when it is used in a large amount for communication equipment with movement, the body becomes heavy and the mobility of the communication equipment is reduced. Problems arise.

  On the other hand, for graphite, the specific gravity is relatively small, so the above-mentioned problem as seen in ferrite does not occur, but the powder is bulky, so it is difficult to increase the filling amount into the matrix. As a result, there is a problem that the effect of improving the electromagnetic wave suppression performance due to the blending of graphite is limited.

Patent Document 2 proposes an electromagnetic wave absorbing sheet obtained by blending carbon nanocoils having a predetermined size with a resin.
Carbon nanocoils are carbon nanofibers with a helical structure, and due to their unique shape, they have excellent electrical and mechanical properties, and by mixing them, suppression of electromagnetic waves from several GHz to several tens of GHz is achieved. Can be obtained.

By blending a carbon nanocoil used in Patent Document 2 with a resin, a resin composition can be provided with a good electromagnetic wave suppression function. However, the carbon nanocoil is a spiral of ultrafine carbon nanofibers. It is easily wound by shearing force during melt kneading with resin. The carbon nanocoil that is broken to shorten the coil length loses its original electrical and mechanical characteristics and cannot obtain the intended electromagnetic wave suppression performance.
Moreover, in patent document 2, examination about the chemical resistance requested | required in uses, such as a housing | casing of an electronic component, is not made | formed.

Japanese Patent Laid-Open No. 2005-11878 JP 2009-60060 A

  The present invention solves the above-mentioned problems of the prior art and has excellent conductivity, mechanical strength, heat resistance, chemical resistance and molding processability, and particularly excellent electromagnetic waves in a frequency range of about 2 to 2.5 GHz. It is an object of the present invention to provide a thermoplastic resin composition for suppressing electromagnetic waves having an inhibitory property and a molded product thereof.

As a result of intensive studies to solve the above problems, the present inventors have used a polymer alloy of an aromatic polycarbonate resin and a polyester resin as a thermoplastic resin, and by blending carbon nanocoils, thereby producing an aromatic polycarbonate resin. It has been found that chemical resistance can be further imparted to the original mechanical strength, heat resistance, and moldability, and electromagnetic wave suppression performance can be enhanced particularly in the frequency range of about 2 to 2.5 GHz.
According to the present invention, since carbon nanocoils are used as the conductivity imparting material, it is possible to obtain excellent electromagnetic wave suppression properties and further mechanical properties derived from the helical structure. As described above, the carbon nanocoil is easily broken when the resin composition is melt-kneaded, but by adding a polyester resin to the aromatic polycarbonate resin, chemical resistance is imparted and the viscosity of the composition is lowered. The breakage of the carbon nanocoil during melt kneading is prevented, and the original good electromagnetic wave suppression performance of the carbon nanocoil is obtained.

  In particular, the presence of carbon nanocoils on the continuous phase side of a sea-island structure or a co-continuous structure, which will be described later, formed of an aromatic polycarbonate resin and a polyester resin, allows a good conductive network of carbon nanocoils to be formed. It is formed inside and high electromagnetic wave suppression property is obtained.

  The present invention has been achieved based on such knowledge, and the gist thereof is as follows.

[1] It includes (A) an aromatic polycarbonate resin, (B) a polyester resin, and (C) carbon nanocoils, and (C) carbon nanocoils are present in a continuous phase formed of a resin component. An electromagnetic wave suppressing resin composition.

[2] The content ratio of (A) aromatic polycarbonate resin to the total of (A) aromatic polycarbonate resin and (B) polyester resin is 50% by mass to 99% by mass, and (C) carbon nanocoil is aromatic. The resin composition for suppressing electromagnetic waves according to [1], wherein the resin composition is present in a continuous phase of an aromatic polycarbonate resin.

[3] The resin composition for suppressing electromagnetic waves according to [1] or [2], wherein the content of (C) the carbon nanocoil is 1% by mass or more and 30% by mass or less.

[4] The electromagnetic wave suppressing resin composition according to any one of [1] to [3], wherein the (B) polyester resin is a polyethylene terephthalate resin and / or a polybutylene terephthalate resin.

[5] An electromagnetic wave suppressing resin molded article obtained by injection molding the electromagnetic wave suppressing resin composition according to any one of [1] to [4].

[6] The resin molded product for suppressing electromagnetic waves according to [5], which is a casing of the electronic device or an internal part of the electronic device.

  The resin composition for suppressing electromagnetic waves of the present invention has excellent electrical conductivity, mechanical strength, heat resistance, chemical resistance, molding processability and electromagnetic wave suppression, and particularly good in a frequency range of about 2 to 2.5 GHz. Therefore, it can be suitably used as a constituent material for casings and internal parts of electrical / electronic / OA equipment parts, machine parts, vehicle parts, mobile phones and the like.

  In the present invention, the content ratio of (A) aromatic polycarbonate resin to the total of (A) aromatic polycarbonate resin and (B) polyester resin is 50% by mass or more and 99% by mass or less, and (C) carbon nanocoil is It is preferably present in the continuous phase of the aromatic polycarbonate resin (claim 2).

  Moreover, it is preferable that content of (C) carbon nanocoil in a composition is 1 to 30 mass% (Claim 3).

  Moreover, as (B) polyester resin, a polyethylene terephthalate resin and / or a polybutylene terephthalate resin are preferable (Claim 4).

  The resin molded product for suppressing electromagnetic waves of the present invention is formed by injection molding the resin composition for suppressing electromagnetic waves of the present invention, and has excellent electrical conductivity, mechanical strength, heat resistance, chemical resistance, It is useful as a casing and internal parts for electrical / electronic / OA equipment parts, machine parts, vehicle parts, mobile phones, etc. due to molding processability and electromagnetic wave suppression, and to reduce the thickness and weight of various structural materials. (Claims 5 and 6).

6 is a graph showing measurement results of electromagnetic wave absorption performance in Examples 1 and 4 and Comparative Example 1.

  Hereinafter, embodiments of the resin composition for suppressing electromagnetic waves and the resin molded product for suppressing electromagnetic waves of the present invention will be described in detail.

[(A) aromatic polycarbonate resin]
The aromatic polycarbonate resin (A) used in the resin composition for suppressing electromagnetic waves of the present invention is a thermoplastic aromatic polycarbonate resin produced by reacting an aromatic dihydroxy compound with a carbonate precursor such as phosgene or carbonic acid diester. It is a coalescence or copolymer. This reaction can be carried out by a known method, for example, an interfacial method is employed when phosgene is used, and a transesterification method in which the reaction is carried out in a molten state when carbonic acid diester is used.

  As aromatic dihydroxy compounds, 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A), tetramethylbisphenol A, bis (4-hydroxyphenyl) -p-diisopropylbenzene, hydroquinone, resorcinol, 4,4 -Dihydroxydiphenyl etc. are mentioned, Preferably bisphenol A is mentioned. Further, for the purpose of further enhancing the flame retardancy, a compound or oligomer having both terminal phenolic OH groups having a siloxane structure and / or a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compound is used. You can also.

  Examples of the carbonate precursor to be reacted with the aromatic dihydroxy compound include phosgene, diaryl carbonates such as diphenyl carbonate and ditolyl carbonate, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate.

  (A) The molecular weight of the aromatic polycarbonate resin is preferably in the range of 16,000 to 30,000 as the viscosity average molecular weight converted from the solution viscosity measured at a temperature of 25 ° C. using methylene chloride as the solvent. It is preferably 17,000 to 28,000, particularly preferably 18,000 to 26,000. (A) If the viscosity average molecular weight of the aromatic polycarbonate resin is less than 16,000, the mechanical strength is insufficient, and if it exceeds 30,000, moldability tends to be difficult, and the viscosity condition of the resin composition described later is satisfied. It is difficult to do so.

  In order to obtain (A) an aromatic polycarbonate resin having a desired molecular weight, a known method such as a method using a terminal terminator or a molecular weight regulator or a selection of polymerization reaction conditions is employed. Examples of the terminal terminator or molecular weight regulator include phenol, pt-alkylphenol, 2,4,6-tribromophenol, long chain alkylphenol, aliphatic carboxylic acid, hydroxybenzoic acid, and aliphatic carboxylic acid chloride. Can be mentioned.

[(B) Polyester resin]
The (B) polyester resin (thermoplastic polyester resin) used in the electromagnetic wave suppression resin composition of the present invention is composed of a dicarboxylic acid component comprising a dicarboxylic acid or a reactive derivative thereof, and a diol or an ester derivative thereof. It is a polymer or copolymer obtained by a condensation reaction mainly comprising a diol component.

  In the production of the polyester resin (B) according to the present invention, in the presence of a polycondensation catalyst containing titanium, germanium, antimony or the like, the dicarboxylic acid component and the diol component are reacted while heating, according to a conventional method, It is performed by discharging by-product water or lower alcohol out of the system. Here, it is possible to take either a batch type polymerization method or a continuous type polymerization method, and it is also possible to increase the degree of polymerization by solid phase polymerization.

  The dicarboxylic acids may be either aromatic dicarboxylic acids or aliphatic dicarboxylic acids, but aromatic dicarboxylic acids are preferred from the viewpoints of heat resistance and dimensional stability. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and 4,4′-biphenyl ether. Dicarboxylic acid, 4,4′-biphenylmethane dicarboxylic acid, 4,4′-biphenylsulfone dicarboxylic acid, 4,4′-biphenylisopropylidenedicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4′-dicarboxylic acid Acid, 2,5-anthracene dicarboxylic acid, 2,6-anthracene dicarboxylic acid, 4,4′-p-ter-phenylenedicarboxylic acid, 2,5-pyridinedicarboxylic acid, etc., and these substituted products (for example, Alkyl group-substituted products such as 5-methylisophthalic acid) and reactive derivatives (eg dimethyl terephthalate) Le, alkyl ester derivatives such as diethyl terephthalate) and the like can also be used.

  Of these, terephthalic acid, 2,6-naphthalenedicarboxylic acid and their alkyl ester derivatives are more preferred, and terephthalic acid and its alkyl ester derivatives are particularly preferred. These aromatic dicarboxylic acids may be used alone or in combination of two or more, and together with the aromatic dicarboxylic acid, an aliphatic dicarboxylic acid such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, One or more alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid may be used in combination.

  Examples of the diols include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propanediol, triethylene glycol, 1,4-butanediol, Aliphatic diols such as neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol, 2,2-dimethyl-1,3-propanediol 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, cyclohexanediol, trans- or cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol; Alicyclic diols such as p-xylene diol, bisphenol A, tetrabromobisphenol A, tetrabromobisphenol A bis (2-hydroxyethyl ether) Aromatic Geo etc. - can be exemplified Le, and the like, can also be used these substituents.

  Of these, ethylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol are more preferable, and ethylene glycol is particularly preferable from the viewpoints of heat resistance, dimensional stability, and the like. These may be used alone or in combination of two or more. Further, as the diol component, one or more kinds of long chain diols having a molecular weight of 400 to 6,000, that is, polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, etc. May be copolymerized in combination with the above diols.

  Moreover, the (B) polyester resin which concerns on this invention can also be branched by introduce | transducing a small amount of branching agents. Although there is no restriction | limiting in the kind of branching agent, A trimesic acid, a trimellitic acid, a trimethylol ethane, a trimethylol propane, a pentaerythritol etc. are mentioned.

  Preferred specific examples of the (B) polyester resin used in the present invention include polyethylene terephthalate resin (PET), polypropylene terephthalate resin (PPT), polybutylene terephthalate resin (PBT), and polyhexylene. Terephthalate resin, polyethylene naphthalate resin (PEN), polybutylene naphthalate resin (PBN), poly (1,4-cyclohexanedimethylene terephthalate) resin (PCT), polycyclohexylcyclohexylene -G (PCC) and the like. Among these, polyethylene terephthalate resin, polypropylene terephthalate resin, and polybutylene terephthalate resin are preferable from the viewpoint of fluidity and impact resistance, and particularly polyethylene terephthalate resin and / or polybutylene terephthalate resin. Preferably, it is preferable in terms of obtaining excellent electromagnetic wave suppression performance due to the effect of reducing the viscosity of the composition and the effect of preventing breakage of the carbon nanocoil, and polyethylene terephthalate resin is particularly preferable.

  Specific examples of other thermoplastic polyester resins include, for example, polypivalolactone resins by ring-opening polymerization of lactone, poly (ε-caprolactone) resins, and the like, and liquid crystal polymers that form liquid crystals in a molten state (Thermotropic Liquid Crystals). Polymer; TLCP) and the like. Specifically, commercially available liquid crystal polyester resins include X7G from Eastman Kodak, Xyday from Dartco, Econo from Sumitomo Chemical, Vectra from Seranis.

  The polyethylene terephthalate resin particularly preferably used in the present invention is obtained by a condensation reaction of terephthalic acid as a main component as a dicarboxylic acid component and ethylene glycol as a diol component as a main component. It is a saturated polyester polymer or copolymer, and is a thermoplastic polyester resin containing ethylene terephthalate units as repeating units, preferably 70 mol% or more, more preferably 80 mol% or more.

  The polyethylene terephthalate resin contains diethylene glycol, which is a side reaction product during polymerization, as a copolymerization component. The amount of diethylene glycol is the amount of the diol component used in the polymerization reaction. It is preferable that it is 0.5 mol% or more in 100 mol% of whole quantity, Usually, it is 6 mol% or less, and it is preferable that it is 5 mol% or less especially.

The intrinsic viscosity of the (B) polyester resin used in the present invention may be appropriately selected and determined, but is usually 0.4 to 2 dL / g, preferably 0.5 to 1.5 dl / g, more preferably 0.6 to 1.3 dl / g. It is preferable that the intrinsic viscosity be 0.4 dL / g or more because mechanical properties and residence heat stability in the resin composition of the present invention tend to be improved. Conversely, it is preferable that the intrinsic viscosity be less than 2 dL / g because the fluidity of the resin composition tends to be improved.
The intrinsic viscosity is a value measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1).

The terminal carboxyl group concentration of the (B) polyester resin used in the present invention is usually 3 to 60 μeq / g, preferably 5 to 50 μeq / g, more preferably 7 to 40 μeq / g. When the terminal carboxyl group is 60 μeq / g or less, the mechanical properties of the resin composition tend to be improved. Conversely, when the terminal carboxyl group concentration is 3 μeq / g or more, the residence heat stability of the resin composition is stabilized. It tends to improve the properties, which is preferable.
The terminal carboxyl group concentration of the polyester resin is such that 0.5 g of a polyester resin such as polyethylene terephthalate resin or polybutylene terephthalate resin is dissolved in 25 mL of benzyl alcohol, and a 0.01 mol / L benzyl alcohol solution of sodium hydroxide is used. Can be obtained by titration.

[Content Ratio of (A) Aromatic Polycarbonate Resin and (B) Polyester Resin]
In the resin composition for suppressing electromagnetic waves of the present invention, the content ratio of (A) aromatic polycarbonate resin and (B) polyester resin is such that (A) aromatic polycarbonate resin is excessively large and (B) polyester resin is too small. , (B) It is not possible to sufficiently improve the chemical resistance by adding the polyester resin and the electromagnetic wave suppression effect, (A) Too little aromatic polycarbonate resin, (B) polyester When there is too much resin, (A) aromatic polycarbonate resin original mechanical strength, heat resistance, moldability, etc. will be impaired.

  Therefore, (A) aromatic polycarbonate resin is 50-99 mass% with respect to the sum total of (A) aromatic polycarbonate resin and (B) polyester resin, especially 60-90 mass%, Furthermore, 65-80 mass%. It is preferable to use so that it becomes.

  The total content of (A) aromatic polycarbonate resin and (B) polyester resin in the electromagnetic wave suppression resin composition of the present invention is preferably 50 to 99% by mass, particularly preferably 60 to 95% by mass. If the content of these resin components is too small, the moldability and impact resistance may be impaired. If the content is too large, the content of other components will be relatively small, and the desired electromagnetic wave suppression property cannot be obtained. There is a case.

  Moreover, when it remove | deviates from the said range, in the micro form of the below-mentioned resin composition, it will become impossible to form the continuous phase by aromatic polycarbonate resin.

[(C) Carbon nanocoil]
The carbon nanocoil (C) used in the present invention has an average coil length of 1 to 100 μm, an average coil diameter of 1 to 1000 nm, an average coil pitch of 1 to 1000 nm, particularly an average coil length of 10 to 40 μm, an average coil diameter of 1 to 1000 nm, and an average coil A pitch of 1 to 1000 nm, particularly an average coil length of 20 to 40 μm, an average coil diameter of 400 to 800 nm, and an average coil pitch of 400 to 800 nm are preferable. By setting this range, an excellent electromagnetic wave absorbing effect can be obtained.

  The average fiber diameter (wire diameter) of the carbon nanocoil is usually about 1 to 500 nm, preferably about 50 to 300 nm.

  As for the average coil length of the carbon nanocoils of the present invention, 100 carbon nanocoils are arbitrarily selected, and 100 carbon nanocoils are imaged at a magnification of 2000 times with a scanning electron microscope (SEM). The average value of 100 when the coil length is measured visually. The average coil diameter, the average coil pitch, and the average fiber diameter are average values when observed with an SEM image (2000 times) of 100 carbon nanocoils arbitrarily selected in the same manner as the average coil length.

Commercially available products may be used for such carbon nanocoils. For example, an alumina substrate carrying a catalyst for carbon nanocoils (hereinafter referred to as “alumina substrate with catalyst”) is 100 to 1000 ° C., preferably 500 Heat CVD (Chemical) which is heated to about 800 ° C., and is grown by spraying a mixed gas of a hydrocarbon such as acetylene and an inert gas on the heated alumina substrate with catalyst.
It can also be produced by the Vapor Deposition method.

For the carbon nanocoil catalyst, for example, an indium / tin / iron catalyst is preferably used. Examples of such indium / tin / iron-based catalysts include metal hydrochlorides, and specific examples include iron chloride such as iron trichloride (FeCl ₃ ), indium chloride such as indium trichloride (InCl ₃ ), A mixed oxide obtained by calcining a precipitate produced by a coprecipitation method from a mixed solution with tin chloride such as tin chloride (SnCl ₂ ) at 300 to 1000 ° C., preferably 500 to 900 ° C. is suitably used. Further, as the indium / tin / iron-based catalyst, metal nitrate, metal sulfate, or metal organic acid salt may be used in addition to the above-described metal hydrochloride. In addition, powders, such as metal oxides, such as iron oxide, an indium oxide, and a tin oxide, may be mixed with such a catalyst, for example. Further, as a catalyst for carbon nanocoil, in addition to the above-mentioned indium / tin / iron-based ternary catalyst, a catalyst not containing indium oxide, for example, a tin / iron-based binary catalyst, specifically, A binary catalyst of iron oxide and tin oxide may be used.
For example, water, isopropyl alcohol (IPA), or alcohols such as ethanol can be used as the solvent of the mixed solution.

  In addition, as an inert gas mixed with a hydrocarbon such as acetylene, for example, helium, argon or the like is used.

  By controlling the composition of the carbon nanocoil catalyst to be used, the growth time, the heating temperature of the alumina substrate with the catalyst, the type of hydrocarbon, the concentration and flow rate of hydrocarbon, etc. when producing the carbon nanocoil by the thermal CVD method, The coil length, coil diameter, coil pitch, and the like of the obtained carbon nanocoil can be appropriately controlled.

  In addition, by irradiating the carbon nanocoil with ultrasonic waves or the like, it is possible to shorten the coil length or the like and change the properties of the carbon nanocoil.

  The content of the (C) carbon nanocoil in the electromagnetic wave suppressing resin composition of the present invention is preferably 1 to 30% by mass, particularly preferably 5 to 20% by mass. If the content of (C) carbon nanocoil in the composition is too small, sufficient conductivity and electromagnetic wave suppression cannot be obtained, and if it is too large, the moldability, strength of the molded product, surface properties, etc. are impaired. This is not preferable.

  In the present invention, (C) the carbon nanocoil retains the uniform dispersibility to the resin composition and the form of the carbon nanocoil during melt kneading (the carbon nanocoil is stretched or broken to change its shape. From the viewpoint of preventing (A), the resin composition for suppressing electromagnetic waves of the present invention is configured as a carbon nanocoil masterbatch obtained by previously mixing (A) a part of an aromatic polycarbonate resin and (C) a carbon nanocoil (A It is preferably blended with the remainder of the aromatic polycarbonate resin, (B) the polyester resin, and other components used as necessary.

  Hereinafter, the manufacturing method of this carbon nanocoil masterbatch is demonstrated.

  First, a carbon nanocoil is added to an organic solvent capable of dissolving an aromatic polycarbonate resin to prepare a dispersion, and a casting liquid is prepared by dissolving a part of the (A) aromatic polycarbonate resin in this dispersion. To do. After casting this casting solution, the organic solvent is removed by evaporation to obtain a resin composition sheet comprising an aromatic polycarbonate resin and carbon nanocoils, and this sheet is cut into an appropriate size.

  The organic solvent for dispersing the carbon nanocoils is not limited as long as it dissolves the aromatic polycarbonate resin, and is appropriately determined according to the type of the aromatic polycarbonate resin used. For example, chloroform, dichloromethane, Examples include methyl ethyl ketone (MEK), toluene, tetrahydrofuran (THF) and the like. Among these, dichloromethane, chloroform, and the like are preferable from the viewpoint of ease of dissolution of the resin and suppression of bubble generation during evaporation.

  Although there is no restriction | limiting in particular about aromatic polycarbonate resin content and carbon nanocoil content in casting liquid, aromatic polycarbonate resin content is 40-99 mass%, carbon nanocoil content is 1-60 mass%, It is preferable to add the aromatic polycarbonate resin and the carbon nanocoil in such a ratio that a carbon nanocoil masterbatch having an aromatic polycarbonate resin and carbon nanocoil content described below can be obtained.

  The casting film may be naturally dried or may be heated and dried at about 50 ° C. The thickness of the casting film is preferably about 0.01 to 3 mm after drying.

  In addition, the particle size (length of the largest diameter portion) of the carbon nanocoil master batch obtained by cutting the casting film is preferably about 0.01 to 5 mm, and the carbon nanocoil master batch in the carbon nanocoil master batch is The coil content is preferably 1 to 60% by mass, and the balance is preferably an aromatic polycarbonate resin.

[(D) Phosphorus flame retardant]
The resin composition for suppressing electromagnetic waves of the present invention may contain (D) a phosphorus-based flame retardant for the purpose of imparting flame retardancy to the composition. (D) The phosphorus-based flame retardant is not particularly limited as long as it is a compound containing phosphorus in the molecule, but is represented by the following general formula (1) from the viewpoint of flame retardancy and the effect of further reducing the viscosity of the composition. Phosphate ester compounds are preferred.

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be substituted with an alkyl group, p, q, r, and s are each independently 0 or 1, t is an integer of 1 to 5, and X represents an arylene group.)

  The phosphate ester compound represented by the general formula (1) is a condensed phosphate ester having t of 1 to 5, and t is an average value of a mixture of the condensed phosphate esters having different t. It becomes.

In the general formula (1), X represents an arylene group, for example, a divalent group derived from a dihydroxy compound such as resorcinol, hydroquinone, bisphenol A and the like. When R ^{1 to} R ⁴ are an aryl group, examples of the aryl group include a phenyl group and a naphthyl group.

  Specific examples of the phosphate ester compound represented by the general formula (1) include, when resorcinol is used as the dihydroxy compound of X in the general formula (1), phenyl resorcinol polyphosphate, cresyl resorcinol polyphosphate Phenyl cresyl resorcin polyphosphate, xylyl resorcin polyphosphate, phenyl-pt-butylphenyl resorcin polyphosphate, phenyl isopropylphenyl resorcin polyphosphate, cresyl xylyl resorcin polyphosphate, phenyl -Isopropylphenyl, diisopropylphenyl, resorcinol polyphosphate, etc.

  These (D) phosphorus flame retardants may be used alone or in combination of two or more.

  (D) It is preferable to mix | blend a phosphorus flame retardant so that content in the resin composition for electromagnetic wave suppression may be 20 mass% or less, for example, 5-20 mass%. (D) If the compounding quantity of a phosphorus flame retardant is less than 5 mass%, the target flame retardance may not be obtained, or moldability may fall. Moreover, when the compounding quantity of (D) phosphorus flame retardant exceeds 20 mass%, heat resistance and mechanical strength may fall. The more preferable content of the phosphorus flame retardant (D) in the electromagnetic wave suppressing resin composition is 10 to 20% by mass.

[(E) Polyfluoroethylene]
In order to further improve the flame retardancy, (E) polyfluoroethylene may be blended in the electromagnetic wave suppressing resin composition of the present invention. (E) As polyfluoroethylene, what has fibril formation ability, and disperse | distributes easily in a thermoplastic resin, and the thing which shows the tendency which couple | bonds thermoplastic resins and makes a fibrous material is preferable.

Moreover, in order to improve the external appearance of the molded article which melt-molded the resin composition containing (E) polyfluoroethylene, it is preferable to use the covering polyfluoroethylene coat | covered with the organic type polymer. As this coated polyfluoroethylene, the content ratio of polyfluoroethylene in the coated polyfluoroethylene is 40 to 95% by mass, especially 43 to 80% by mass, more preferably 45 to 70% by mass, and particularly 47 to 60% by mass. Some are preferred.
By blending such a coated polyfluoroethylene, it is possible to suppress the occurrence of white foreign matters on the surface of the molded product while maintaining good flame retardancy. When the content ratio of the polyfluoroethylene in the coated polyfluoroethylene is less than 40% by mass, the flame retardancy may be lowered. On the other hand, when it exceeds 95% by mass, white spot foreign matter may be increased.

  The polyfluoroethylene coated with the organic polymer is preferably polytetrafluoroethylene (PTFE), and among them, it tends to disperse easily in the polymer and bond the polymers together to form a fibrous material. Therefore, those having fibril forming ability are preferred.

  Such a coated polyfluoroethylene can be produced by various known methods. For example, (1) a polyfluoroethylene particle aqueous dispersion and an organic polymer particle aqueous dispersion are mixed and coagulated or sprayed. (2) A method in which an organic polymer is polymerized in the presence of an aqueous dispersion of polyfluoroethylene particles, and then polymerized and then powdered by coagulation or spray drying. (3) After emulsion polymerization of a monomer having an ethylenically unsaturated bond in a dispersion obtained by mixing an aqueous dispersion of polyfluoroethylene particles and an aqueous dispersion of organic polymer particles, solidification or spray drying And the like, and the like.

  The organic polymer covering polyfluoroethylene is not particularly limited, but is preferably a polymer having high affinity with a thermoplastic resin from the viewpoint of dispersibility when blended with the resin.

  Specific examples of monomers for producing this organic polymer include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, t-butylstyrene, o-ethylstyrene, p-chlorostyrene. Aromatic vinyl monomers such as o-chlorostyrene, 2,4-dichlorostyrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate , Ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, octadecyl acrylate, octadecyl methacrylate , Cyclohexyl acrylate (Meth) acrylic acid ester monomers such as cyclohexyl methacrylate; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; α, β-unsaturated carboxylic acids such as maleic anhydride; N-phenylmaleimide; Maleimide monomers such as N-methylmaleimide and N-cyclohexylmaleimide; Glycidyl group-containing monomers such as glycidyl methacrylate; Vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; Vinyl acetate and vinyl butyrate Examples thereof include vinyl carboxylate monomers; olefin monomers such as ethylene, propylene, and isobutylene; and diene monomers such as butadiene, isoprene, and dimethylbutadiene. These monomers can be used alone or in admixture of two or more.

  Among these monomers, from the viewpoint of affinity with (A) aromatic polycarbonate resin and (B) polyester resin, aromatic vinyl monomer, (meth) acrylic acid ester monomer, cyanide One or more monomers selected from vinyl monomers are preferable, (meth) acrylic acid ester monomers are particularly preferable, and monomers containing 10% by mass or more of these monomers are preferable.

  Examples of the coated polyfluoroethylene preferably used in the present invention include Metabrene A-3800 and KA-5503 manufactured by Mitsubishi Rayon Co., Ltd., and Poly TS AD001 manufactured by PIC.

  Content of (E) polyfluoroethylene in the resin composition for electromagnetic wave suppression of this invention is 0.01-1 mass%, Furthermore, 0.05-0.9 mass%, Especially 0.1-0. It is preferably 7% by mass. (E) When the content of polyfluoroethylene is less than 0.01% by mass, the effect of improving the flame retardancy may be insufficient, and when it exceeds 1% by mass, the appearance of the molded product may be deteriorated. is there.

  The blending ratio of (D) phosphorus flame retardant and (E) polyfluoroethylene in the electromagnetic wave suppression resin composition and (D) phosphorus flame retardant / (E) polyfluoroethylene weight ratio are well balanced. From the point of obtaining a resin composition having performance, it is usually 0.1 to 1000, more preferably 1 to 100, and particularly 2 to 60.

[(F) Release agent]
A release agent can be blended with the resin composition of the present invention in order to improve the mold releasability at the time of molding.

  Examples of the release agent include aliphatic carboxylic acids and alcohol esters thereof, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15000, polysiloxane silicone oil, and the like.

  Examples of the aliphatic carboxylic acid include saturated or unsaturated, linear or cyclic, aliphatic 1 to 3 carboxylic acids. Among these, monovalent or divalent carboxylic acids having 6 to 36 carbon atoms are preferable, and aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms are particularly preferable. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, melissic acid, tetrariacontanoic acid, Examples include montanic acid, adipic acid, and azelaic acid.

  The aliphatic carboxylic acid component in the aliphatic carboxylic acid ester has the same meaning as the above-mentioned aliphatic carboxylic acid. On the other hand, the alcohol component of the aliphatic carboxylic acid ester includes a saturated or unsaturated, linear or cyclic monovalent or polyhydric alcohol. These may have a substituent such as a fluorine atom or an aryl group, and among them, a monovalent or polyvalent saturated alcohol having 30 or less carbon atoms is preferable, particularly 30 or less carbon atoms, a saturated aliphatic monovalent or Polyhydric alcohols are preferred.

  Specific examples of such alcohol components include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane. And dipentaerythritol. The aliphatic carboxylic acid ester may contain an aliphatic carboxylic acid and / or alcohol as an impurity, and may be a mixture of a plurality of aliphatic carboxylic acid esters.

  Specific examples of the aliphatic carboxylic acid ester include beeswax (a mixture based on myricyl palmitate), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate, glycerin di Examples thereof include stearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate and the like.

  Examples of the aliphatic hydrocarbon having a number average molecular weight of 200 to 15000 include liquid paraffin, paraffin wax, microwax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomer having 3 to 12 carbon atoms. Here, the aliphatic hydrocarbon includes alicyclic hydrocarbons. Moreover, these hydrocarbon compounds may be partially oxidized.

  Among these aliphatic hydrocarbons, paraffin wax, polyethylene wax, or partial oxides of polyethylene wax are preferable, and paraffin wax and polyethylene wax are particularly preferable. The number average molecular weight is preferably 200 to 5,000. These aliphatic hydrocarbons may be used alone or in combination of two or more at any ratio as long as the main component is within the above range.

  Examples of the polysiloxane silicone oil include dimethyl silicone oil, phenylmethyl silicone oil, diphenyl silicone oil, fluorinated alkyl silicone, and the like. These may be used alone or in combination of two or more.

  The content of the release agent in the resin composition of the present invention may be selected and determined as appropriate. However, if the amount is too small, the release effect is not sufficiently exhibited. Deterioration, mold contamination at the time of molding, etc. may be a problem. Therefore, the content of the release agent is 0.001 to 2 parts by mass with respect to 100 parts by mass of the total amount of (A) aromatic polycarbonate resin, (B) polyester resin, and (C) carbon nanocoil, Among these, 0.01 to 1 part by mass is preferable.

[(G) Phosphorus stabilizer]
A phosphorus compound can be added to the resin composition of the present invention in order to improve thermal stability.
Any known phosphorous compound can be used. Specific examples include phosphorus oxo acids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; acidic pyrophosphate metal salts such as acidic sodium pyrophosphate, acidic potassium pyrophosphate, and acidic calcium pyrophosphate; phosphoric acid Examples thereof include phosphates of Group 1 or Group 10 metals such as potassium, sodium phosphate, cesium phosphate, and zinc phosphate; organic phosphate compounds, organic phosphite compounds, and organic phosphonite compounds.

  Among them, triphenyl phosphite, tris (monononylphenyl) phosphite, tris (monononyl / dinonyl phenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, monooctyl diphenyl phosphite, Dioctyl monophenyl phosphite, monodecyl diphenyl phosphite, didecyl monophenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) ) Organic phosphites such as octyl phosphite are preferred.

Specific examples of such an organic phosphite compound include, for example, “Adeka Stub 1178”, “Adeka Stub 2112”, “Adeka Stub HP-10”, “Adeka Stub AX-71” manufactured by Adeka Corporation (trade names, the same applies hereinafter). "JP-351", "JP-360", "JP-3CP" manufactured by Johoku Chemical Industry Co., Ltd., "Irgaphos 168" manufactured by Ciba Specialty Chemicals Co., Ltd., and the like.
In addition, 1 type may contain phosphorus stabilizer and 2 or more types may contain it by arbitrary combinations and a ratio.

  When the resin composition of the present invention contains (G) phosphorus stabilizer, the content of (G) phosphorus stabilizer is (A) aromatic polycarbonate resin, (B) polyester resin, and (C) carbon nano It is usually 0.001 parts by mass or more, preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, and usually 1 part by mass or less, preferably 100 parts by mass for the total amount of coils. 0.7 parts by mass or less, more preferably 0.5 parts by mass or less. If the amount of the phosphorus stabilizer is too small, the heat stabilizing effect may be insufficient, and if the amount of the phosphorus stabilizer is too large, the effect may reach a peak and may not be economical.

[(H) Antioxidant]
An antioxidant can be further added to the resin composition of the present invention.
Examples of the antioxidant include hindered phenol-based antioxidants. Specific examples thereof include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl). ) Propionate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N′-hexane-1,6-diylbis [3- (3,5-di-) tert-butyl-4-hydroxyphenylpropionamide), 2,4-dimethyl-6- (1-methylpentadecyl) phenol, diethyl [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl ] Methyl] phosphoate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesi Tylene-2,4,6-triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -o-cresol, ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4- Hydroxy-m-tolyl) propionate], hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-tert- Butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert-butyl-4- (4,6-bis ( Octylthio) -1,3,5-triazin-2-ylamino) phenol and the like.

  Among them, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate preferable.

Specific examples of such phenolic antioxidants include “Irganox 1010” (registered trademark, the same shall apply hereinafter) manufactured by Ciba Specialty Chemicals, “Irganox 1076”, and “Adeka Stub” manufactured by Adeka. AO-50 "," ADK STAB AO-60 "and the like.
In addition, 1 type may contain antioxidant and 2 or more types may contain it by arbitrary combinations and a ratio.

  When the resin composition of the present invention contains (H) an antioxidant, the content of (H) the antioxidant is (A) an aromatic polycarbonate resin, (B) a polyester resin, and (C) a carbon nanocoil. It is 0.001 mass part or more normally with respect to 100 mass parts of total amounts, Preferably it is 0.01 mass part or more, and is 1 mass part or less normally, Preferably it is 0.5 mass part or less. When the content of the antioxidant is less than the lower limit of the above range, the antioxidant effect may be insufficient, and when the content of the antioxidant exceeds the upper limit of the above range, the effect reaches a peak. And may become less economical.

[Other ingredients]
In the resin composition for suppressing electromagnetic waves of the present invention, an ultraviolet absorber, a dye / pigment, an antistatic agent, an antifogging agent, a lubricant / antiblocking agent, and fluidity improvement, as long as the purpose of the present invention is not impaired as necessary. Agents, compatibilizers, plasticizers, dispersants, resin additives such as antibacterial agents, impact resistance improvers, inorganic fillers and the like can be blended.

[Viscosity (Q value)]
The resin composition of the present invention provides chemical resistance by blending (A) an aromatic polycarbonate resin with (B) a polyester resin, and lowers the viscosity of the resin composition. The shape of the carbon nanocoil when melt-kneading is maintained.

In obtaining the effect of maintaining this form, the resin composition for suppressing electromagnetic waves of the present invention has a Q value of 1 × 10 ⁻² to a viscosity (Q value) based on JIS K7210 Appendix C measured by the following method. It is preferable that it is 80 * 10 ^<-2 > cm ^{< 3} > / sec, especially 3 * 10 ^<-2 > -70 * 10 ^<-2 > cm ^{< 3} > / sec.

  When these Q values are smaller than the above range, the effect of maintaining the form of (C) carbon nanocoils cannot be obtained sufficiently, and when it is larger than the above range, impact resistance is lowered.

<Method for measuring viscosity (Q value)>
After drying the obtained resin composition pellets at 120 ° C. for 4 hours or more, the composition was subjected to a method according to JIS K7210 Annex C using a high load flow tester at 280 ° C. under a load of 160 kgf. The flow rate Q value (unit: 10 ⁻² cm ³ / sec) per unit time was measured to evaluate the fluidity. An orifice having a diameter of 1 mm and a length of 10 mm was used. It shows that it is excellent in fluidity | liquidity, so that Q value is high.

[Micro form of resin composition]
When the resin composition for electromagnetic wave suppression of the present invention containing (A) an aromatic polycarbonate resin and (B) a polyester resin as the resin component is observed with an electron microscope, the (A) aromatic polycarbonate resin and (B) It has a micro-form consisting of a continuous phase (hereinafter referred to as “sea phase”) by one of the polyester resins and a discontinuous phase (hereinafter referred to as “island phase”) by the other, or both resins each form a continuous phase. And has a micro morphology consisting of a co-continuous phase.

  That is, the polymer alloy formed by mixing the resin A and the resin B has a large proportion of the resin A, and when the proportion of the resin B is small, the sea island in which the island phase of the resin B is dispersed in the sea phase composed of the resin A. It becomes a structure. In this case, resin A is a continuous phase, while resin B is a discontinuous phase divided into islands. From this state, when the blending amount of the resin A is decreased and the blending amount of the resin B is increased, the sea phase and the island phase are reversed, and the island phase of the resin A is dispersed in the sea phase composed of the resin B. In this case, the resin B is a continuous phase, but the resin A is a discontinuous phase divided into islands. In the blending region between the blending ratio of the resin A / resin B with the sea-island structure and the blending ratio of the resin B / resin A with the sea-island structure, the polymer alloy is such that both the resin A and the resin B are continuous. (Both phases are observed as a continuous phase), resulting in a sponge-like two-phase separation structure in which both resins form a continuous phase and are finely dispersed. Such a phase structure is called a co-continuous structure.

  In the present invention, (C) carbon nanocoils are mainly present in a continuous phase in a sea-island structure or a bicontinuous structure formed by (A) an aromatic polycarbonate resin and (B) a polyester resin. It is preferable that excellent electromagnetic wave suppression is obtained by forming a good conductive network with carbon nanocoils. Here, “mainly” means that (C) 50% or more, preferably 65% or more, and most preferably 85% or more of the carbon nanocoil is present in the continuous phase.

Note that the microscopic observation with an electron microscope is performed as follows. An ultra-microtome equipped with a cryo device (REICHERT-NSSEIPCS) cut out from a central portion of a molded product having a length of 50 mm, a width of 30 mm, and a thickness of 1 mm obtained by molding a resin composition and mounted with a cryo device (REICHERT-NSSEIPCS). Using a Leica ULTRACUT CUT), an ultrathin section with a thickness of 100 nm was cut out with a diamond knife at −100 ° C. so that the plane perpendicular to the flow direction at the center of the wall thickness became the observation plane. Stained with ruthenium tetroxide (RuO ₄ ), the dispersion state of carbon nanocoils is observed with a transmission electron microscope (manufactured by JEOL Ltd., model: JEM1200EXII type). Since the carbon nanocoil is observed in dark color, the aromatic polycarbonate resin is observed in gray, and the polyester resin is observed in light color, the number of carbon nanocoils present in the continuous phase is observed among 100 carbon nanocoils. Determine what percentage of the carbon nanocoils in the resin composition are present in the continuous phase.

  The electromagnetic wave suppressing resin composition of the present invention has a sea-island structure micro-form in which (A) an aromatic polycarbonate resin constitutes a sea phase and (B) a polyester resin constitutes an island phase, from the viewpoint of electromagnetic wave suppression. (C) The carbon nanocoil is preferably present mainly in the sea phase of the (A) aromatic polycarbonate resin.

[Production method]
The production method of the electromagnetic wave suppressing resin composition of the present invention is not particularly limited, for example,
(1) (A) aromatic polycarbonate resin, (B) polyester resin, (C) carbon nanocoil (preferably carbon nanocoil masterbatch), and (D) a phosphorus-based flame retardant compounded as necessary (E) (2) When using liquid (D) phosphorus flame retardant, after melt-kneading components other than (D) phosphorus flame retardant in advance, A liquid (D) phosphorus flame retardant that has been separately heated at 50 to 120 ° C. and melt kneaded may be used.

  In order to produce an electromagnetic wave suppressing resin composition in which (C) carbon nanocoil is mainly present in the sea phase of (A) aromatic polycarbonate resin, as described above, (C) carbon nanocoil is (A) aromatic. Using a carbon nanocoil masterbatch blended with a part of the polycarbonate resin, (A) the aromatic polycarbonate resin (B) so that the (A) aromatic polycarbonate resin is the sea phase and the (B) polyester resin is the island phase. The resin composition for suppressing electromagnetic waves may be produced by using more than the polyester resin and adjusting the degree of kneading so that (C) the carbon nanocoil is present in the sea phase of the (A) aromatic polycarbonate resin. .

[Molding method]
The resin composition for suppressing electromagnetic waves of the present invention is used as a resin material for production (molding) of various products (molded products). As the molding method, a conventionally known method of molding a molded product from a thermoplastic resin material can be applied. Specifically, general injection molding methods, ultra-high speed injection molding methods, injection compression molding methods, two-color molding methods, hollow molding methods such as gas assist, molding methods using heat insulating molds, rapid heating molds Molding method used, foam molding (including supercritical fluid), insert molding method, in-mold coating (IMC) molding method, extrusion molding method, film molding method, sheet molding method, thermoforming method, rotational molding method, lamination Examples include molding methods and press molding methods. In particular, (C) carbon nanocoil is oriented along the surface layer of the molded product during molding, so that high electromagnetic wave suppression can be obtained. The method is preferred.

[Electromagnetic wave suppression resin molded product]
The electromagnetic wave suppressing resin molded product of the present invention is formed by injection molding of the electromagnetic wave suppressing resin composition of the present invention, and is a housing for electrical / electronic / OA equipment parts, machine parts, vehicle parts, mobile phones and the like. It is suitable as a body and internal parts, especially as a housing and internal parts for electronic devices.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded.

  The raw material used for manufacture of each resin composition in an Example and a comparative example is as follows.

<(A) Aromatic polycarbonate resin>
Poly-4,4-isopropylidene diphenyl carbonate: “trade name: Iupilon (registered trademark) S-3000” manufactured by Mitsubishi Engineering Plastics Co., Ltd. (viscosity average molecular weight: 21,000)

<(B) Polyester resin>
Polyethylene terephthalate resin: “Novapex GG500” manufactured by Mitsubishi Chemical Corporation (inherent viscosity 0.76 dl / g, terminal carboxyl group concentration: 15 μeq / g)

  Polybutylene terephthalate resin: “Novaduran 5020” (Intrinsic viscosity 1.20 dl / g, terminal carboxyl group concentration: 20 μeq / g) manufactured by Mitsubishi Engineering Plastics Co., Ltd.

<(C) Carbon nanocoil>
In a liquid in which 9 parts by mass of carbon nanocoil (average length of about 20 μm, average wire diameter of about 150 nm, average coil diameter of about 500 nm, average pitch of about 500 nm) manufactured by Osaka Science and Technology Center is dispersed in 70 parts by mass of dichloromethane, 21 parts by mass of an aromatic polycarbonate resin (Iupilon (registered trademark) S-3000) was dissolved, cast into a stainless steel vat, and then heated at 50 ° C. for 5 minutes to remove dichloromethane to a thickness of 0. A 2 mm thin film was obtained. The thin film was cut into 3 mm square to obtain a carbon nanocoil master batch. The carbon nanocoil content of this carbon nanocoil masterbatch is 30% by mass.

<Phosphorus stabilizer>
Phosphorus stabilizer: mono- and di-stearyl acid phosphate, “Adekastab AX-71” manufactured by Adeka

[Preparation of resin composition]
Aromatic polycarbonate resin, polyester resin, carbon nanocoil masterbatch and phosphorus stabilizer are blended so as to have the composition shown in Table 1 (however, in Comparative Example 1, the polyester resin and phosphorus stabilizer are not blended). After being uniformly dispersed by shaking well in a plastic bag, it is melted at a cylinder temperature of 300 ° C. with a twin-screw extruder (HAAKE “Minilab”), and kneaded at a screw rotation speed of 80 rpm. The pellet of the resin composition was obtained by cutting into 3 mm length with a pelletizer.

[Evaluation methods]
(1) Viscosity (Q value)
The Q value of the aromatic polycarbonate resin used for the production of the resin composition and the Q value of the resin composition in which all components were blended as shown in Table 1 with respect to this aromatic polycarbonate resin were measured by the following methods.
After drying the pellets of the aromatic polycarbonate resin or the obtained resin composition at 120 ° C. for 4 hours or more, using a high load type flow tester according to JISK7210 Annex C, conditions of 280 ° C. and a load of 160 kgf The flow rate Q value (unit: 10 ⁻² cc / sec) per unit time of the resin or composition was measured below to evaluate the fluidity. An orifice having a diameter of 1 mm and a length of 10 mm was used. It shows that it is excellent in fluidity | liquidity, so that Q value is high.

(2) Electromagnetic wave absorptivity The obtained resin composition pellets were molded at a cylinder temperature of 300 ° C. and a mold temperature of 80 ° C. using an injection molding machine (HAAKE's “Mini Jet”, maximum injection pressure 1200 Bar). Injection molding into a mold cavity (length 50 mm, width 30 mm, thickness 1 mm), and for three obtained injection-molded products, a near-field noise suppression sheet evaluation system, an intra-decoupling ratio measurement system (IEC standard No: According to IEC 62333-2), the Rda value of the magnetic field wave at a frequency of 2 GHz was measured, and the average value was calculated. Although this value depends on the frequency generated from the product and its strength, it is not a value that is generally determined, but is preferably 0.6 dB or more.

  In Examples 1 and 4 and Comparative Example 1, Rda values of magnetic field waves from 0 to 4 GHz were continuously measured.

In addition, a small piece of about 4 × 4 × 1 mm was cut out from the central portion of a molded product having a length of 50 mm, a width of 30 mm, and a thickness of 1 mm, which was molded in the same manner as the above-described electromagnetic wave suppression evaluation sample, and a cryo device (REICHERT-NSSEIPCS). ) With an ultramicrotome (ULTRACUT CUT made by Leica) at -100 ° C. with a diamond knife, an ultra-thin slice with a thickness of 100 nm so that the plane perpendicular to the flow direction of the central thickness becomes the observation plane Next, the cut ultrathin section was stained with ruthenium tetroxide (RuO ₄ ), and the dispersion state of carbon nanocoils was observed using a transmission electron microscope (manufactured by JEOL Ltd., model: JEM1200EXII type). As a result, in Examples 1 to 3, almost all of the carbon nanocoils were contained in the sea phase of the aromatic polycarbonate resin. Was confirmed to exist. In Example 4, the ratio of the aromatic polycarbonate resin was small and barely a co-continuous structure, and almost all of the carbon nanocoils were dispersed in the aromatic polycarbonate resin phase.

[result]
The evaluation results are shown in Table 1 and FIG. In FIG. 1, PC represents an aromatic polycarbonate resin, PBT represents a polybutylene terephthalate resin, and CNC represents a carbon nanocoil.

From Table 1 and FIG. 1, it can be seen that the resin composition for suppressing electromagnetic waves of the present invention is excellent in electromagnetic wave suppressing properties in a frequency region of about 2 to 2.5 GHz.
On the other hand, in the comparative example 1 which has not mix | blended the polyester resin, it will be inferior to the electromagnetic wave suppression property in this frequency range.
From the comparison between Example 1 and Example 2, as the polyester resin, polyethylene terephthalate resin is more effective in improving electromagnetic wave suppression than polybutylene terephthalate resin. From the comparison between Example 1 and Example 4, it can be seen that blending more aromatic polycarbonate resin than polyester resin and having carbon nanocoils in the continuous phase of the aromatic polycarbonate resin is superior in electromagnetic wave suppression.

Claims (6)

  Electromagnetic wave suppression characterized by comprising (A) aromatic polycarbonate resin, (B) polyester resin, and (C) carbon nanocoil, wherein (C) carbon nanocoil is present in a continuous phase formed of a resin component. Resin composition.   (A) The content ratio of (A) aromatic polycarbonate resin with respect to the total of aromatic polycarbonate resin and (B) polyester resin is 50 mass% or more and 99 mass% or less, and (C) carbon nanocoil is aromatic polycarbonate resin. The resin composition for suppressing electromagnetic waves according to claim 1, wherein the resin composition is present in a continuous phase.   (C) Content of carbon nanocoil is 1 mass% or more and 30 mass% or less, The resin composition for electromagnetic waves suppression of Claim 1 or Claim 2 characterized by the above-mentioned.   The resin composition for suppressing electromagnetic waves according to any one of claims 1 to 3, wherein the (B) polyester resin is a polyethylene terephthalate resin and / or a polybutylene terephthalate resin.   An electromagnetic wave suppressing resin molded product obtained by injection molding the electromagnetic wave suppressing resin composition according to any one of claims 1 to 4.   The resin molded product for suppressing electromagnetic waves according to claim 5, which is a casing of an electronic device or an internal part of the electronic device.

Images