JP7646034B2 - Polycarbonate resin composition, molded article, and method for producing polycarbonate resin composition - Google Patents

Description

The present disclosure relates to a polycarbonate resin composition, a molded article, and a method for producing a polycarbonate resin composition.

Polycarbonate resins are excellent in transparency, mechanical properties, heat resistance, and the like. However, because of their high surface resistivity ( ¹⁰ Ω/sq or more), dust particles such as dirt and debris tend to adhere to the surface of molded articles, which may cause problems such as malfunctions when used in electrical equipment components.

For this reason, antistatic polycarbonate resin compositions containing highly antistatic ionic liquids or conductive metal oxides are being investigated. However, adding a large amount of antistatic agent to improve antistatic performance can cause discoloration and a decrease in transparency, making it difficult to achieve both antistatic properties and transparency.

Methods for imparting antistatic properties while maintaining transparency include the addition of surfactants such as quaternary ammonium salts and sulfonates, conductive polymers such as polythiophene and polyaniline, and conductive metal oxides such as indium oxide and tin oxide. Methods for imparting antistatic properties to polycarbonate resin compositions have progressed from adding a single antistatic agent to adding multiple antistatic agents.

For example, Patent Document 1 (JP Patent No. 4870256) discloses metal salts selected from phosphonium sulfonate, potassium salt and sodium salt of diphenylsulfone-3-sulfonic acid, and potassium salt and sodium salt of perfluoroalkanesulfonic acid as antistatic agents. Patent Document 2 (JP Patent Publication 2009-107286 A) discloses phosphonium benzenesulfonate and phosphonium naphthylsulfonate as antistatic agents.

Patent No. 4870256 JP 2009-107286 A

However, the above antistatic agents have high total light transmittance and ensure transparency, but have high surface resistivity (10 ¹² Ω/sq to 10 ¹³ Ω/sq), and thus do not have sufficient antistatic properties. In addition, since there is a high correlation between antistatic properties and dust adhesion, the agents were not sufficiently effective against hydrophilic dust stains such as sand and dirt, and hydrophobic dust stains such as soot and oily smoke.

The present disclosure has been made to solve the above problems, and aims to provide a polycarbonate resin composition and molded article that are resistant to both hydrophilic and hydrophobic dust stains while maintaining transparency.

As a result of extensive research aimed at solving the above problems, the inventors have discovered that a synergistic effect can be achieved by combining a polycarbonate resin with a phosphonium salt-based ionic liquid and composite nanofibers, thereby achieving an anti-fouling effect that makes it difficult for both hydrophilic and hydrophobic dust stains to adhere while maintaining transparency.
The present disclosure relates to the following polycarbonate resin compositions:

A polycarbonate resin composition containing 100 parts by weight of polycarbonate resin (A), 0.5 to 5.0 parts by weight of a phosphonium salt-based ionic liquid (B), and 0.01 to 0.09 parts by weight of composite nanofiber (C).

According to the present disclosure, it is possible to provide a polycarbonate resin composition and a molded article that are resistant to both hydrophilic and hydrophobic dust stains while maintaining transparency.

The following describes an embodiment of the present disclosure.

Embodiment 1
<Polycarbonate resin composition>
The polycarbonate resin composition of the present embodiment contains 100 parts by weight of a polycarbonate resin (A), 0.5 to 5.0 parts by weight of a phosphonium salt-based ionic liquid (B), and 0.01 to 0.09 parts by weight of a composite nanofiber (C).

The polycarbonate resin composition of the present embodiment contains polycarbonate resin (A), phosphonium salt-based ionic liquid (B), and composite nanofibers (C), and thus exhibits an antifouling effect that makes it difficult for both hydrophilic and hydrophobic dust stains to adhere while ensuring transparency. The reasons for using each of the above components are explained below.

Since there is a high correlation between antistatic properties and dust adhesion, it has been common to add an antistatic agent to reduce the surface resistivity in order to improve dust adhesion. However, since polycarbonate resin originally has a high surface resistivity (10 ¹⁴ Ω/sq or more), the surface resistivity tends not to be reduced even if an antistatic agent is added. In addition, although polycarbonate resin is excellent in transparency, mechanical properties, heat resistance, etc., when an antistatic agent is added, it tends to cause cloudiness and deterioration of mechanical properties. Therefore, in consideration of the above problems, the present inventors have considered adding various antistatic agents to polycarbonate resin.

First, phosphonium salt-based ionic liquid was investigated as an antistatic agent. Although the addition of a small amount of phosphonium salt-based ionic liquid improved the antistatic properties somewhat, the surface resistivity was high (10 ¹² Ω/sq to 10 ¹³ Ω/sq), and sufficient antistatic properties were not obtained. Furthermore, adding a large amount of phosphonium salt-based ionic liquid to lower the surface resistivity resulted in a decrease in transparency.

Next, the inventors investigated the addition of composite nanofibers as an auxiliary additive to the phosphonium salt-based ionic liquid. By adding the composite nanofibers, the phosphonium salt-based ionic liquid clings to the surface of the nanofibers and is aligned in the fiber direction, forming a conductive path, which reduces the surface resistivity, and a polycarbonate resin composition was obtained that is resistant to both hydrophilic and hydrophobic dust stains.
Each component will be described in detail below.

(Polycarbonate resin (A))
The polycarbonate resin (A) contained in the polycarbonate resin composition of the present disclosure is not particularly limited, and various types can be used.For example, aromatic polycarbonates produced by a solution method (interfacial polycondensation method) or a melting method (ester exchange method) of a dihydric phenol and a carbonate precursor can be used.That is, those produced by reacting a dihydric phenol with phosgene by an interfacial polycondensation method, a dihydric phenol with diphenyl carbonate, etc. by an ester exchange method, etc. can be used.

Dihydric phenols include various ones, particularly 2,2-bis(4-hydroxyphenyl)propane [bisphenol A], bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl)cycloalkane, bis(4-hydroxyphenyl)oxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ketone, etc., or halogen-substituted derivatives thereof. Other examples include hydroquinone, resorcin, catechol, etc. These may be used alone or in combination of two or more kinds, but among these, bis(hydroxyphenyl)alkanes are preferred, and bisphenol A is more preferred.

Carbonate precursors include carbonyl halides, carbonyl esters, haloformates, etc., specifically phosgene, dihaloformates of dihydric phenols, diphenyl carbonate, dimethyl carbonate, diethyl carbonate, etc.

Polycarbonate resin (A) includes not only new materials but also polycarbonate resins recycled from used products. Any commercially available grade can be used, but optical grades with high transmittance are preferable. For example, Iupilon ML200, ML300, ML400, HL3003, HL3503 (Mitsubishi Engineering Plastics Co., Ltd.), SD Polyca 303-10, 303-30 (Sumika Polycarbonate Co., Ltd.), Lexan LS-1, LS-2, LS-3 (SABIC Innovative Plastics Japan LLC), Panlite L-1225Z, L-1225ZL (Teijin Co., Ltd.), Toughlon LC1500, LC1700 (Idemitsu Kosan Co., Ltd.), etc. can be used.

(Phosphonium Salt-Based Ionic Liquid (B))
The polycarbonate resin composition of the present disclosure contains a phosphonium salt-based ionic liquid (B). By containing the phosphonium salt-based ionic liquid (B), it is possible to improve antistatic properties (dust adhesion prevention properties).

Examples of the phosphonium salt-based ionic liquid (B) include tributyldodecylphosphonium bis(trifluoromethanesulfonyl)imide, tributyldodecylphosphonium bromide, tetrabutylphosphonium dodecylbenzenesulfonate, trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide, triethylpentylphosphonium bis(trifluoromethylsulfonyl)imide, triethyloctylphosphonium bis(trifluoromethylsulfonyl)imide, tri-n-butylmethylphosphonium bis(trifluoromethylsulfonyl)imide, tetrabutylphosphonium tetraphenylborate, etc. From the viewpoint of availability, it is preferable to use tributyldodecylphosphonium bis(trifluoromethanesulfonyl)imide, tributyldodecylphosphonium bromide, and tetrabutylphosphonium dodecylbenzenesulfonate.

Examples of tributyldodecylphosphonium bis(trifluoromethanesulfonyl)imide include tributyldodecylphosphonium bis(trifluoromethanesulfonyl)imide (Fujifilm Wako Pure Chemical Industries, Ltd.) and IL-AP3 (Koei Chemical Industry Co., Ltd.). Examples of tributyldodecylphosphonium bromide include tributyldodecylphosphonium bromide (Fujifilm Wako Pure Chemical Industries, Ltd.). Examples of tetrabutylphosphonium dodecylbenzenesulfonate include Elecut S-418 (Takemoto Oil Co., Ltd.).

The content of the phosphonium salt-based ionic liquid (B) in the present disclosure is 0.5 to 5.0 parts by weight, preferably 0.5 to 4.0 parts by weight, and more preferably 0.5 to 3.0 parts by weight, relative to 100 parts by weight of polycarbonate resin. If the content of the phosphonium salt-based ionic liquid (B) exceeds 5.0 parts by weight, not only will the thermal stability at high temperatures decrease significantly and the material will be more susceptible to coloring, but the mechanical properties may also decrease significantly. If the content of the phosphonium salt-based ionic liquid (B) is less than 0.5 parts by weight, the dust adhesion prevention properties will decrease.

(Composite Nanofiber (C))
The polycarbonate resin composition of the present disclosure contains the composite nanofiber (C). By containing the composite nanofiber (C), it is possible to improve antistatic properties (dust adhesion prevention properties).

In this disclosure, the composite nanofiber (C) refers to a fiber having a diameter on the order of nanometers, which is a composite of two or more metal oxides. Examples of metal oxides include silicon oxide (silica), aluminum oxide (alumina), zinc oxide, titanium oxide, calcium oxide, tin oxide, indium oxide, etc., with alumina and silica being preferred. In addition, the composite nanofiber (C) is preferably a nanofiber formed by combining alumina and silica.

The composite nanofiber (C) preferably has an average fiber diameter of 100 nm or less. If the average fiber diameter of the composite nanofiber (C) exceeds 100 nm, Rayleigh scattering occurs, resulting in reduced transparency. From the viewpoint of transparency, the average fiber diameter of the composite nanofiber (C) is more preferably 60 nm or less, and even more preferably 30 nm or less. The shape of the composite nanofiber (C) is not particularly limited, but may be, for example, fibrous, rod-like, tubular, hollow rod-like, core-shell fibrous, etc., with the core-shell fibrous shape being preferred.

The average fiber diameter of the composite nanofiber (C) is determined by taking electron microscope images of a sufficient number (e.g., 100 or more) of composite nanofibers (C) using an electron microscope (SEM, TEM, etc.), measuring the diameters (diameters) of these composite nanofibers (C), and taking the arithmetic average.

In addition, it is preferable that the refractive index of the composite nanofiber (C) at a wavelength of 589.3 nm of the sodium D line is close to 1.58, which is the refractive index of the polycarbonate resin (A) at a wavelength of 589.3 nm of the sodium D line. If the refractive index of the composite nanofiber (C) is farther from 1.58, the difference between the refractive index of the polycarbonate resin (A) and the refractive index of the composite nanofiber (C) causes phenomena such as scattering and refraction, resulting in a decrease in transparency. From the viewpoint of transparency, the refractive index of the composite nanofiber (C) is preferably in the range of 1.40 to 2.00, more preferably in the range of 1.50 to 1.80, even more preferably in the range of 1.50 to 1.70, and even more preferably in the range of 1.58 to 1.60.

The refractive index can be adjusted by using a compound that combines metal oxides with different refractive indices. For example, in the case of core-shell fibers, a compound with alumina in the core and silica in the shell can be used.

Examples of composite nanofibers that can be used (C) include R30SP-M2 and R30SP-H1 (Admatechs Co., Ltd.).

The content of composite nanofiber (C) in the present disclosure is 0.01 to 0.09 parts by weight, preferably 0.02 to 0.08 parts by weight, and more preferably 0.02 to 0.07 parts by weight, per 100 parts by weight of polycarbonate resin. If the content of composite nanofiber (C) exceeds 0.09 parts by weight, haze increases and transparency may not be obtained. If the content of composite nanofiber (C) is less than 0.01 parts by weight, dust adhesion prevention properties decrease.

(Additives)
The polycarbonate resin composition of the present disclosure may contain additives such as a heat stabilizer, an ultraviolet absorber, and a light stabilizer, so long as the additives do not impede the object of the present disclosure.

[Heat stabilizer]
The polycarbonate resin composition of the present disclosure may contain a heat stabilizer to improve thermal stability, since the inclusion of the ionic liquid (B) or the composite nanofiber (C) leads to hydrolysis, reduced thermal stability, and yellowing.

As heat stabilizers, it is preferable to use antioxidants such as hindered phenols, phosphorus-based, and sulfur-based, which may be used alone or in a mixture of two or more types.

The amount of heat stabilizer added in this disclosure is not particularly limited, and the composition ratio when two or more types are mixed is also not particularly limited, but it is desirable to adjust each time depending on the required physical properties.

Examples of hindered phenol antioxidants include known ones such as 2,6-di-tert-butyl-p-cresol, tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, stearyl β-(3',5'-di-tert-butyl-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, 1,3,5-trimethyl-2,4,6-tris(3',5'-di-tert-butyl-4-hydroxybenzyl)benzene, and triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate]. Among these, from the viewpoint of heat resistance and stability, tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, stearyl β-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate, and 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 are preferred.

Examples of phosphorus-based antioxidants include tris(2,4-di-tert-butylphenyl)phosphite, diphenyl mono(2-ethylhexyl)phosphite, diphenyl monodecyl phosphite, pentaerythritol bis(2,6-di-tert-butyl-4-phenyl phosphite), 2,2'-methylene bis(4,6-di-tert-butylphenyl)-2-ethylhexyl phosphite, distearyl pentaerythritol diphosphite, tri(mono Examples of known phosphate esters include tris(2,4-di-tert-butylphenyl)phosphite, alkanol (C=12-16) 4,4'-isopropylidenediphenol triphenyl phosphite polycondensate, bis[2,4-di-tert-butyl-6-methylphenyl]ethyl phosphite, pentaerythritol bis(2,4-di-tert-butylphenyl phosphite), triallyl phosphite, and tetrakis(2,4-tert-butylphenyl)-4,4'-biphenyl diphosphonate. Among these, tris(2,4-di-tert-butylphenyl)phosphite, diphenyl mono(2-ethylhexyl)phosphite, diphenyl monodecyl phosphite, pentaerythritol bis(2,6-di-tert-butyl-4-phenyl phosphite), and 2,2'-methylenebis(4,6-di-tert-butylphenyl)-2-ethylhexyl phosphite are preferred from the viewpoint of heat resistance stability.

Examples of sulfur-based antioxidants include known ones such as pentaerythritol tetrakis (3-lauryl thiopropionate), dilauryl-3,3'-thiodipropionate, and dioctadecyl-3,3'-thiodipropionate. Of these, pentaerythritol tetrakis (3-lauryl thiopropionate) is preferred from the viewpoint of heat resistance and stability.

The content of the heat stabilizer in this disclosure is preferably 0.05 to 10 parts by weight, and more preferably 0.05 to 3.0 parts by weight, per 100 parts by weight of polycarbonate resin (A).

[Ultraviolet absorber]
The polycarbonate resin composition of the present invention is often used in outdoor products and may contain an ultraviolet absorbing agent since it yellows due to ultraviolet light.

Examples of UV absorbers include known ones such as hydroxybis(dimethylbenzyl)phenylbenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol], 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol), and 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine).

Among the above, from the viewpoint of weather resistance stability, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol], 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol), and 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine) are preferred. The above ultraviolet absorbers may be used alone or in a mixture of two or more.

The amount of UV absorber added in this disclosure is not particularly limited, and the composition ratio when two or more types are mixed is also not particularly limited, but it is desirable to adjust each time depending on the physical properties required.

The content of the ultraviolet absorber in this disclosure is preferably 0.05 to 10 parts by weight, more preferably 0.05 to 3.0 parts by weight, per 100 parts by weight of polycarbonate resin (A).

[Light stabilizer]
The polycarbonate resin composition of the present disclosure is often used in outdoor products and may contain a light stabilizer since it is prone to yellowing due to ultraviolet light.

Examples of light stabilizers include known ones such as tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, a mixed ester of 1,2,3,4-butanetetracarboxylic acid, 1,2,3,6,6-pentamethyl-4-piperidinol, and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, and bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

Among the above, from the viewpoint of weather resistance stability, a mixed ester of 1,2,3,4-butanetetracarboxylic acid, 1,2,3,6,6-pentamethyl-4-piperidinol, and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane is preferred. The above light stabilizers may be used alone or in a mixture of two or more.

The amount of light stabilizer added in this disclosure is not particularly limited, and the composition ratio when two or more types are mixed is also not particularly limited, but it is desirable to adjust each time depending on the physical properties required.

The content of the light stabilizer in this disclosure is preferably 0.05 to 10 parts by weight, and more preferably 0.05 to 3.0 parts by weight, per 100 parts by weight of polycarbonate resin (A).

(Other additives)
Other additives that can be used in the present disclosure include antistatic agents, plasticizers, release agents, flame retardants, flame retardant auxiliaries, dyes, pigments, and the like, so long as they do not impede the object of the present disclosure.

As the antistatic agent, any of the known ionic liquids can be selected and used, such as phosphonium salt-based ionic liquids (B) such as trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide, triethylpentylphosphonium bis(trifluoromethylsulfonyl)imide, triethyloctylphosphonium bis(trifluoromethylsulfonyl)imide, tri-n-butylmethylphosphonium bis(trifluoromethylsulfonyl)imide, and tetrabutylphosphonium tetraphenylborate; ammonium salt-based ionic liquids such as tributylmethylammonium bis(trifluoromethylsulfonyl)imide (FC-4400, 3M Japan); pyridinium salt-based ionic liquids such as N-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (CIL-312, Nippon Carlit Co., Ltd.); imidazolium salt-based ionic liquids; and pyrrolidinium salt-based ionic liquids.

Plasticizers may be selected from known plasticizers such as polyethylene glycol, polyamide oligomer, ethylene bisstearamide, phthalate esters, adipic acid esters, polystyrene oligomers, polyethylene wax, silicone oil, and mineral oil.

The release agent may be selected from known agents such as polyethylene wax, silicone oil, stearyl phosphite, long-chain carboxylic acids, metal salts of long-chain carboxylic acids, and higher fatty acid esters of monohydric or polyhydric alcohols.

Flame retardants may be selected from any of the known flame retardants, including phosphorus-based flame retardants such as bisphenol A bis(diphenyl phosphite), tricresyl phosphate, triphenyl phosphate, and tris-3-chloropropyl phosphate; bromine-based flame retardants such as 2,2-bis[4-(3,3-dibromopropoxyl)-3,5-dibromophenyl]propane, bis(3,5-dibromo-4-dibromopropyloxyphenyl)sulfone, ethylene bispentabromobenzene, and hexabromocyclododecane; silicone-based flame retardants; and hydroxide-based flame retardants such as magnesium hydroxide and aluminum hydroxide.

Flame retardant assistants can be selected from antimony compounds such as antimony trioxide and others.

<Method for producing polycarbonate resin composition>
The method for producing the polycarbonate resin composition of the present disclosure is not particularly limited, and known methods for producing polycarbonate resin compositions can be widely adopted. For example, polycarbonate resin (A), phosphonium salt-based ionic liquid (B), composite nanofiber (C), and additives to be blended as necessary are mixed and kneaded. As a kneading method, for example, any physical blend such as melt kneading, solvent cast blending, latex blending, polymer complex, etc. can be used, but the melt kneading method is preferred. The temperature of the melt kneading is not particularly limited, but is usually in the range of 240 to 320 ° C.

The equipment used for the above kneading includes, for example, a tumbler, Henschel mixer, rotary mixer, super mixer, ribbon tumbler, V blender, etc., and the mixed components are uniformly dispersed by the above kneading method, then melt-kneaded and pelletized. A single-screw or multi-screw extruder is generally used for melt-kneading pelletization, but a Banbury mixer, roller, co-kneader, blast mill, Prabender blastograph, etc. can also be used, and these are operated batchwise or continuously.

Alternatively, instead of melt-kneading, the resin pellets, hydrolysis resistance improver, and other additives can be mixed together, and the mixed components can be used as the molding resin, which is then melt-kneaded in the heating barrel of the molding machine, a process known as mold blending.

Embodiment 2
The molded article according to the present embodiment is made of the above-mentioned polycarbonate resin composition. Since the molded article according to the present embodiment is made of the above-mentioned polycarbonate resin composition, it has an effect of ensuring transparency and being less susceptible to both hydrophilic dust stains and hydrophobic dust stains.

The molded article of this embodiment can be produced by melt-kneading the polycarbonate resin composition containing the above-mentioned polycarbonate resin (A), phosphonium salt-based ionic liquid (B), and composite nanofibers (C), pelletizing the mixture, and molding the mixture by various molding methods. It can also be produced by directly molding the resin melt-kneaded in an extruder without going through pellets.

The shape of the molded product is not particularly limited, but can be appropriately selected depending on the application and purpose of the molded product. For example, plate-like, plate-like, rod-like, sheet-like, film-like, cylindrical, annular, circular, elliptical, porous, foamed, polygonal, irregularly shaped, hollow, frame-like, box-like, panel-like, etc. are included. Specific examples include automobile interior panels, automobile (two-wheeled vehicle) headlamp lenses, windows, housings, etc., and special shapes. In addition, the molded product may have an uneven shape transferred to its surface, or may have a three-dimensional shape with a three-dimensional curved surface. Furthermore, when used as a sheet, film, plate-like, etc., it may be a multilayer structure laminated with other resin sheets.

The molding method is not particularly limited, and any conventionally known molding method can be used, such as injection molding, injection compression molding, extrusion molding, profile extrusion, transfer molding, hollow molding, gas-assisted hollow molding, blow molding, extrusion blow molding, IMC (in-mold coating) molding, rotational molding, multi-layer molding, two-color molding, insert molding, sandwich molding, foam molding, pressure molding, inflation molding, etc. Furthermore, surface treatments such as corona discharge treatment, flame treatment, plasma treatment, and ozone treatment that are normally used industrially can also be applied.

(Total light transmittance)
The molded article of this embodiment has excellent transparency even at a thickness of about 0.5 to 6.0 mm, and the total light transmittance of a molded article having a thickness of 2.0 mm is 86% or more, and preferably 88% or more.

Here, total light transmittance refers to all light that is transmitted when light equivalent to a D65 light source is incident on the object being measured, and the D65 light source refers to light that reproduces an outdoor lighting environment. The state without a test piece is taken as 100%, and the closer the value is to 100%, the more transparent the material is.

The total light transmittance can be measured, for example, according to JIS K7361-1:1997 "Plastics - Test method for total light transmittance of transparent materials - Part 1: Single beam method" using a molded product with a thickness of 2.0 mm and an ultraviolet-visible-near infrared (UV-Vis-NIR) spectrophotometer (Solid Spec-3700 DUV, manufactured by Shimadzu Corporation) at a temperature of 23°C.

(Haze)
In the molded article of this embodiment, the haze of a molded article having a thickness of 2.0 mm is 7% or less, and preferably 6% or less.

Here, haze refers to the degree of light scattering, which can cause a material to become opaque even when it does not absorb light. The lower the value, the more transparent the material is.

Haze can be measured, for example, using a haze meter (NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.) at a temperature of 23°C under a D65 light source, using a molded product with a thickness of 2.0 mm, in accordance with a measurement method conforming to JIS K7136:2000 "Determination of haze of plastics - transparent materials".

Moreover, the haze can be calculated by the following formula (1).
Haze (%)=diffuse light component/total light transmittance×100 Formula (1)
The light contained in the total light transmittance includes a parallel light component and a diffuse light component, and the haze is a numerical representation of the proportion of the diffuse light component in the total light transmittance.

The present disclosure is explained in detail below with reference to examples, but the present disclosure is not limited to these.

<Evaluation method>
The evaluation was performed by the following method. The test specimens used in the following evaluations were flat test specimens (100 mm long x 100 mm wide x 2.0 mm thick), which were left for one week in an environment of 23°C temperature and 50% humidity before evaluation.

(1) Transparency (total light transmittance)
The flat test piece was measured at a temperature of 23° C. using an ultraviolet-visible-near infrared (UV-Vis-NIR) spectrophotometer (Solid Spec-3700 DUV, manufactured by Shimadzu Corporation) according to a measurement method conforming to JIS K7361-1:1997 "Test method for total light transmittance of plastics-transparent materials-Part 1: Single beam method." A total light transmittance of 86% or more was considered good.

(2) Transparency (haze)
Using the flat test piece, the haze was measured with a haze meter (NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.) under a D65 light source at a temperature of 23° C. according to the measurement method in accordance with JIS K7136:2000 "Determination of haze for plastics-transparent materials." A haze of 7% or less was considered good.

(3) Antistatic properties (surface resistivity)
The flat test pieces were used to measure the resistivity under the following test conditions using a resistivity meter (Hiresta UP MCP-HT450, manufactured by Mitsubishi Chemical Analytech Co., Ltd.). The smaller the value, the better the antistatic properties. A surface resistivity of less than 10 ¹² Ω/sq was rated "A," and a surface resistivity of 10 ¹² Ω/sq or more was rated "B."
[Test conditions]
Voltage: 1000V
Time: 60 seconds Temperature: 23℃
Humidity: 50%

(4) Dust Adhesion Powders were used that conform to "Test Powders and Test Particles" of JIS Z8901:2006. Kanto loam (JIS test powder 1, type 11) was used for evaluating hydrophilic dust adhesion, and carbon black (JIS test powder 1, type 12) was used for evaluating hydrophobic dust adhesion.
The dust adhesion was evaluated by blowing a certain amount (5 g) of dust onto the surface of the molded article with air, observing the surface of the molded article at 100x magnification using a digital microscope (VHX-5000, manufactured by Keyence Corporation), and determining the dust adhesion rate (dust-adhered area ratio) by image processing. A dust adhesion rate of less than 4% was indicated as "A," and a dust adhesion rate of 4% or more was indicated as "B."

(5) Overall Judgment: A rating of "A" was given to cases where the total light transmittance was 86% or more, the haze was 7% or less, the surface resistivity was less than 10 ¹² Ω/sq, and the hydrophilic and hydrophobic dust adhesion rates were less than 4%, and a rating of "B" was given to cases where any one of the above criteria was not met.

<Examples 1 to 10 and Comparative Examples 1 to 11>
Each component in the composition ratio shown in Tables 1 and 2 was mixed and melt-kneaded at 280°C using a twin-screw kneading extruder (TEX-26SX, manufactured by Shibaura Electric Industries, Ltd.) to prepare 3-5 mm pellets of a polycarbonate resin composition.

The obtained pellets were molded into flat test pieces (100 mm long x 100 mm wide x 2 mm thick) for evaluation (Examples 1-10, Comparative Examples 1-11) using an electric injection molding machine (NEX110IV-9EG, manufactured by Nissei Plastic Industrial Co., Ltd.). The basic conditions for injection molding were a resin temperature of 280°C and a mold temperature of 80°C.

The components shown in Tables 1 and 2 (each component symbolically represented) are as follows:

[Polycarbonate resin: component A]
A-1: Iupilon HL3503 manufactured by Mitsubishi Engineering Plastics Corporation
A-2: Toughlon LC1500 manufactured by Idemitsu Kosan Co., Ltd.
A-3: SD Polyca 303-30 manufactured by Sumika Polycarbonate Co., Ltd.
A-4: Panlite L-1225ZL manufactured by Teijin Limited
A-5: Iupilon HL3003 manufactured by Mitsubishi Engineering Plastics Corporation
A-6: Iupilon SGH1010A (glass fiber 10 parts by weight) manufactured by Mitsubishi Engineering Plastics Corporation

[Phosphonium Salt-Based Ionic Liquid: Component B]
(B-1)
Tributyldodecylphosphonium bis(trifluoromethanesulfonyl)imide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
(B-2)
Tetrabutylphosphonium dodecylbenzenesulfonate (Elecut S-418, manufactured by Takemoto Oil Co., Ltd.)
(B-3)
Tributyldodecylphosphonium bromide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
(B-4)
Tributyldodecylphosphonium bis(trifluoromethanesulfonyl)imide (IL-AP3, manufactured by Koei Chemical Industry Co., Ltd.)

[Ammonium salt-based ionic liquid, pyridinium salt-based ionic liquid: component B′]
(B'-1)
Tributylmethylammonium bis(trifluoromethylsulfonyl)imide (FC-4400, manufactured by 3M Japan Ltd.)
(B'-2)
N-Butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (CIL-312, manufactured by Nippon Carlit Co., Ltd.)

[Composite nanofiber: component C]
(C-1)
Nanofibers made of alumina and silica (R30SP-H1, manufactured by Admatechs Co., Ltd.) (average fiber diameter: 2 to 50 nm, refractive index: 1.60)
(C-2)
Nanofibers made of alumina and silica (R30SP-M2, manufactured by Admatechs Co., Ltd.) (average fiber diameter: 2 to 50 nm, refractive index: 1.58)

[Metal oxide: component C']
(C′-1)
Antimony-doped tin oxide (ATO) [FS-10P, manufactured by Ishihara Sangyo Kaisha, Ltd.] (average fiber diameter: 10-20 nm, refractive index: 2.0-2.2)

The evaluation results (1) to (4) and (5) overall judgment for the obtained flat test specimens for evaluation (Examples 1 to 10 and Comparative Examples 1 to 11) are shown in Tables 1 and 2.

From the evaluation results shown in Table 1, it can be confirmed that in the examples, which are molded articles made of polycarbonate resin compositions that satisfy the constituent requirements of the present disclosure, a polycarbonate resin composition is obtained that has excellent transparency and exhibits an anti-fouling effect in that it is difficult for both hydrophilic and hydrophobic dust stains to adhere.

On the other hand, Comparative Example 1 did not contain components B and C, and therefore had poor antistatic properties and dust adhesion. Comparative Example 2 contained component B but not component C, and therefore had improved transparency and hydrophilic dust adhesion, but had poor antistatic properties and hydrophobic dust adhesion. Comparative Example 5 contained component C but not component B, and therefore had poor antistatic properties and dust adhesion, similar to Comparative Example 1. From these results, it can be confirmed that the inclusion of all components A to C is a necessary constituent element of the present disclosure.

Furthermore, although Comparative Examples 7 to 10 contain all of components A to C, the content of component C in Comparative Example 7 and the content of component B in Comparative Example 9 are both greater than the specified amount, so that although antistatic properties and dust adhesion were improved, transparency was poor. Furthermore, the content of component C in Comparative Example 8 and the content of component B in Comparative Example 10 are both less than the specified amount, so that although transparency was improved, antistatic properties and dust adhesion were poor. From these results, it can be confirmed that the inclusion of all of components A to C, and the respective specified amounts, is a necessary constituent element of the present disclosure.

Furthermore, Comparative Example 3 contained an ammonium salt-based ionic liquid (B'-1) instead of component B, and Comparative Example 4 contained a pyridinium salt-based ionic liquid (B'-2) instead of component B, and therefore had poor antistatic properties and hydrophobic dust adhesion. These results confirm that a phosphonium salt-based ionic liquid (component B) is the optimal ionic liquid.

Furthermore, Comparative Example 6 contained antimony-doped tin oxide (C'-1) instead of component C, and therefore was inferior in transparency, antistatic properties, and hydrophobic dust adhesion rate. Comparative Example 11 contained glass fiber (A-6) instead of component C, and therefore was inferior in antistatic properties and dust adhesion rate. These results confirm that composite nanofibers are optimal as component C.

Although not shown in Tables 1 and 2, when the mechanical properties (tensile strength, tensile elongation at break, and Charpy impact strength) were evaluated in Example 1 and Comparative Example 1, equivalent evaluation results were obtained, confirming that no deterioration in mechanical properties was observed when components B to C were blended with component A.

The embodiments and examples disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

Claims (5)

Contains 100 parts by weight of polycarbonate resin, 0.5 to 5.0 parts by weight of phosphonium salt-based ionic liquid, and 0.01 to 0.09 parts by weight of composite nanofibers ;
The composite nanofiber is made by combining two or more metal oxides,
The metal oxides include alumina and silica;
The composite nanofiber has an average fiber diameter of 100 nm or less,
The composite nanofiber is a polycarbonate resin composition having a refractive index of 1.50 to 1.80 at a wavelength of 589.3 nm of sodium D line . The polycarbonate resin composition according to claim 1, wherein the phosphonium salt-based ionic liquid contains at least one selected from the group consisting of tributyldodecylphosphonium bis(trifluoromethanesulfonyl)imide, tributyldodecylphosphonium bromide, and tetrabutylphosphonium dodecylbenzenesulfonate. The polycarbonate resin composition according to claim 1 or 2, wherein the composite nanofiber is a composite of alumina and silica. A molded article made of the polycarbonate resin composition according to any one of claims 1 to 3. A method for producing the polycarbonate resin composition according to any one of claims 1 to 3, comprising the steps of:
A method for producing a polycarbonate resin composition, comprising melt-kneading a polycarbonate resin, a phosphonium salt-based ionic liquid, and composite nanofibers.