Aromatic polycarbonate resin composition and molded article thereof

Abstract

This aromatic polycarbonate resin composition comprises: 100 parts by weight of (A) an aromatic polycarbonate resin (A component); 0.5-3 parts by weight of (B) a halogenated aromatic polycarbonate or oligomer (B component) as a halogen atom; 0.1-1 part by weight of (C) a polypropylene glycol (C component); 0.01-0.1 parts by weight of (D) an aromatic phosphite-based heat stabilizer (D component); and 0.00035-0.0005 parts by weight of (E) a bluing agent (E component). The resin composition has the feature of having extremely little yellowing during ionizing radiation sterilization and having high transmission visibility.

Description

Aromatic polycarbonate resin composition and molded article thereof

[0001] The present invention relates to an aromatic polycarbonate resin composition containing an aromatic polycarbonate resin, a halogenated aromatic polycarbonate or oligomer, polypropylene glycol, an aromatic phosphite-based heat stabilizer, and a bluing agent, and to a molded article thereof. In particular, the present invention relates to an aromatic polycarbonate resin composition and a molded article thereof that are useful as medical devices and that exhibit very little yellowing during ionizing radiation sterilization and high transmittance visibility.

[0002] Aromatic polycarbonate resins are thermoplastic resins with excellent mechanical strength, transparency, heat resistance, and impact resistance, and are used in a wide range of applications. Due to these excellent properties, the resins are used as components for various medical devices, such as syringes, containers for storing and packaging surgical instruments, artificial lungs, artificial kidneys, anesthesia absorption devices, intravenous connectors and accessories, blood separation devices, and other medical devices, surgical instruments, and other operating instruments.

[0003] These medical applications typically involve complete sterilization. Examples of such sterilization methods include ethylene oxide gas contact treatment, high-temperature moist heat treatment using high-pressure steam in an autoclave, and irradiation with ionizing radiation such as gamma rays or electron beams. Among these, the ethylene oxide method is undesirable due to issues with the safety and toxicity (especially carcinogenicity) of the gas itself, residual gas in the medical instruments being treated, and environmental issues related to waste disposal. Steam sterilization has problems such as material deformation, degradation due to hydrolysis, and high processing costs due to the high-temperature moist heat treatment, as well as the need for a drying step after sterilization. On the other hand, ionizing radiation treatment has the advantages of eliminating residue issues in the product, allowing treatment in a dry state at low temperatures, and relatively low processing costs. Furthermore, ionizing radiation's ability to permeate materials allows sterilization of packaged products, and has therefore become increasingly popular.

[0004] However, when polycarbonate resin is exposed to such ionizing radiation, it undergoes a chemical reaction and turns yellow, which significantly reduces the commercial value of the container in medical applications, as it makes it difficult to accurately see the color of the contents inside.

[0005] Various attempts have been made to prevent this yellowing. For example, a method of offsetting the yellowness by adding a blue colorant to the resin is known. However, although this method can eliminate the yellowness by adjusting the amount of the colorant added, it also results in a darkening of the overall color, which reduces the commercial value of the product.

[0006] Also, a method of adding polyether polyol or its alkyl ether is known (Patent Document 1). Although this method provides some improvement, it is still insufficient, and there is also the problem that the addition of this compound easily causes decomposition and discoloration of the polycarbonate resin during molding processing.

[0007] Further proposed methods include adding an aromatic halogen compound to a polycarbonate resin (Patent Document 2), adding a compound having a cyclic acetal group and a polyalkylene glycol ether or a polyalkylene glycol ester (Patent Document 3), adding an aromatic compound having an oxy group or a carbonyl group and a polyalkylene glycol, a polyalkylene glycol ester or a polyalkylene glycol ester (Patent Document 4), and adding a cinnamyl compound and a polyalkylene glycol, a polyalkylene glycol ether or a polyalkylene glycol ester (Patent Document 5). However, these documents provide insufficient information regarding yellowing of aromatic polycarbonate resin compositions during ionizing radiation sterilization.

[0008] JP-A-62-135556, JP-A-2-129261, JP-A-9-59504, JP-A-9-87506, JP-A-10-25411

[0009] An object of the present invention is to provide an aromatic polycarbonate resin composition and a molded article thereof which exhibit very little yellowing during ionizing radiation sterilization and high diametric visibility. As a result of intensive research conducted to achieve this object, the present inventors have found that by blending an aromatic polycarbonate resin with a halogenated aromatic polycarbonate or oligomer, polypropylene glycol, an aromatic phosphite ester-based heat stabilizer, and a bluing agent, and by appropriately adjusting the amount of bluing agent blended, very little yellowing during ionizing radiation sterilization and high diametric visibility can be achieved, leading to the present invention.

[0010] That is, the present invention provides the following (Configuration 1) to (Configuration 6). (Configuration 1) An aromatic polycarbonate resin composition containing, relative to 100 parts by weight of (A) an aromatic polycarbonate resin (Component A), 0.5 to 3 parts by weight of (B) a halogenated aromatic polycarbonate or oligomer (Component B) in terms of halogen atoms, 0.1 to 1 part by weight of (C) polypropylene glycol (Component C), 0.01 to 0.1 part by weight of (D) an aromatic phosphite ester-based heat stabilizer (Component D), and 0.00035 to 0.0005 parts by weight of (E) a bluing agent (Component E). (Configuration 2) A polycarbonate resin composition according to Configuration 1, further containing, relative to 100 parts by weight of Component A, 0.01 to 0.5 parts by weight of (F) a mold release agent (Component F). (Structure 3) A polycarbonate resin composition in which a 2 mm thick molded plate formed from the polycarbonate resin composition according to Structure 1 or 2 has a YI of 1.0 or less after irradiating it with 25 kilograys (kGy) of cobalt-60 gamma rays. (Structure 4) A polycarbonate resin composition in which a 2 mm thick molded plate formed from the polycarbonate resin composition according to Structure 1 or 2 has an L* of 93 or more after irradiating it with 25 kilograys (kGy) of cobalt-60 gamma rays. (Structure 5) A polycarbonate resin composition in which a 2 mm thick molded plate formed from the polycarbonate resin composition according to Structure 1 or 2 has a b* of 1.0 or less after irradiating it with 25 kilograys (kGy) of cobalt-60 gamma rays. (Structure 6) A molded article formed from the polycarbonate resin composition according to any one of Structures 1 to 5.

[0011] The aromatic polycarbonate resin composition of the present invention exhibits minimal yellowing due to ionizing radiation irradiated for sterilization and exhibits high transmittance visibility. Therefore, it is extremely useful as a medical component for medical products and medical devices that undergo ionizing radiation treatment. In particular, it can be used as a component for artificial dialysis machines, oxygenators, oxygenators, anesthesia inhalation devices, intravenous connectors and accessories, blood centrifuge bowls, surgical instruments, operating room instruments, and the container-like packaging devices for packaging these items, tubes for supplying oxygen to blood, tube connectors, cardiac probes, syringes, and containers for intravenous injections.

[0012] The present invention will be described in detail below. <Aromatic Polycarbonate Resin (Component A)> The aromatic polycarbonate resin used in the present invention is preferably an aromatic polycarbonate resin which may be branched and which is produced by interfacial polymerization of an aromatic dihydroxy compound with phosgene or by transesterification of an aromatic dihydroxy compound with a carbonate diester.

[0013] Examples of aromatic dihydroxy compounds include bis(4-hydroxyphenyl)alkane dihydroxy compounds such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane, and 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane (tetramethylbisphenol A), as well as halogen-containing bis(4-hydroxyphenyl)alkane dihydroxy compounds such as 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane (tetrabromobisphenol A) and 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane (tetrachlorobisphenol A), as well as 1,1-bis(4-hydroxyphenyl)cyclohexane, hydroquinone, resorcinol, and 4,4-dihydroxydiphenyl. Preferred are bis(4-hydroxyphenyl)alkane dihydroxy compounds that may contain halogen, with bisphenol A being particularly preferred. These aromatic dihydroxy compounds may be used alone or in combination.

[0014] The aromatic polycarbonate resin used in the present invention can also be made into a branched polycarbonate by copolymerizing a structural unit containing a trifunctional or higher polyfunctional aromatic compound, if necessary. Suitable examples of the trifunctional or higher polyfunctional aromatic compound used in the branched polycarbonate include trisphenols such as 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2,2,4,6-trimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1-tris(4-hydroxyphenyl)ethane, 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane, 2,6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, and 4-{4-[1,1-bis(4-hydroxyphenyl)ethyl]benzene}-α,α-dimethylbenzylphenol. Of these, 1,1,1-tris(4-hydroxyphenyl)ethane is preferred. The content of structural units derived from such polyfunctional aromatic compounds is preferably 0.03 to 1.5 mol %, more preferably 0.1 to 1.2 mol %, and particularly preferably 0.2 to 1.0 mol %, based on a total of 100 mol % including structural units derived from other divalent components.

[0015] A monovalent aromatic hydroxy compound can be used as a molecular weight modifier for the aromatic polycarbonate resin, such as m- and p-methylphenol, m- and p-propylphenol, p-bromophenol, p-tert-butylphenol, and p-long-chain alkyl-substituted phenol.

[0016] The aromatic polycarbonate resin used in the present invention preferably has a viscosity average molecular weight (Mv) of 15,000 to 40,000, more preferably 16,000 to 30,000, and even more preferably 17,000 to 28,000. When the viscosity average molecular weight is within the above range, sufficient toughness and crack resistance are obtained, and also excellent moldability is achieved.

[0017] The viscosity average molecular weight of the aromatic polycarbonate resin is determined by first calculating the specific viscosity (η ＳＰ) was measured using an Ostwald viscometer from a solution prepared by dissolving 0.7 g of polycarbonate resin material in 100 ml of methylene chloride at 20°C, and the specific viscosity (η ＳＰ ) = (t - t ０ ) / t ０ [t ０ is the number of seconds for methylene chloride to fall, and t is the number of seconds for the sample solution to fall]. ＳＰ ) and the viscosity average molecular weight Mv was calculated using the following formula: ＳＰ / c = [η] + 0.45 × [η] ２ c (where [η] is the intrinsic viscosity) [η] = 1.23 × 10 －４ Mv ０．８３ c=0.7

[0018] <Halogenated Aromatic Polycarbonate or Oligomer (Component B)> From the viewpoint of heat resistance, the halogenated aromatic polycarbonate or oligomer used in the present invention is particularly preferably a brominated aromatic polycarbonate or oligomer represented by the following formula (1).

[0019]

[0020] In formula (1), X represents a bromine atom, and R represents an alkylene group having 1 to 4 carbon atoms, an alkylidene group having 1 to 4 carbon atoms, or —SO ２ In the formula (1), R is preferably a methylene group, an ethylene group, an isopropylidene group, or —SO ２ -, and particularly preferably represents an isopropylidene group.

[0021] The number of repeating units of formula (1) is preferably in the range of 2 to 100 on average, more preferably in the range of 3 to 50, even more preferably in the range of 3.5 to 30, and particularly preferably in the range of 4 to 15. Specific trade names include Fireguard FG-8500 and FG-7500 manufactured by Teijin Limited.

[0022] The brominated polycarbonate or oligomer preferably has a small amount of residual chloroformate terminal groups, with the terminal chlorine content being 0.3 ppm or less, more preferably 0.2 ppm or less. The terminal chlorine content can be determined by dissolving a sample in methylene chloride, adding 4-(p-nitrobenzyl)pyridine to react with the terminal chlorine (terminal chloroformate), and measuring the resultant with an ultraviolet-visible spectrophotometer (U-3200, manufactured by Hitachi, Ltd.). When the terminal chlorine content is 0.3 ppm or less, the thermal stability of the aromatic polycarbonate resin composition and its molded articles is improved, enabling molding at higher temperatures, resulting in a resin composition with superior molding processability.

[0023] The specific viscosity of the brominated polycarbonate or oligomer is preferably in the range of 0.015 to 0.1, more preferably 0.015 to 0.08. The specific viscosity of the brominated polycarbonate or oligomer can be calculated according to the above-mentioned formula for calculating specific viscosity used when calculating the viscosity average molecular weight of the aromatic polycarbonate resin of the present invention.

[0024] The amount of halogenated aromatic polycarbonate or oligomer to be blended is 0.5 to 3 parts by weight, preferably 0.6 to 2 parts by weight, more preferably 0.7 to 1.5 parts by weight, and even more preferably 0.8 to 1.3 parts by weight, in terms of halogen atoms per 100 parts by weight of the aromatic polycarbonate resin. If the amount is less than the above range, it will not be effective in suppressing yellowing due to exposure to ionizing radiation, while if the amount is more than the above range, it will undesirably result in a decrease in mechanical properties and heat resistance.

[0025] <Polypropylene Glycol (Component C)> The polypropylene glycol used in the present invention may be an ether derivative or an ester derivative thereof. Specific examples of the ether derivative of polypropylene glycol include polypropylene glycol methyl ether, polypropylene glycol dimethyl ether, polypropylene glycol dodecyl ether, polypropylene glycol benzyl ether, polypropylene glycol dibenzyl ether, polypropylene glycol-4-nonylphenyl ether, and polytetramethylene glycol.

[0026] Specific examples of the ester derivatives of polypropylene glycol include polypropylene glycol diacetate, polypropylene glycol acetate propionate, polypropylene glycol dibutyrate, polypropylene glycol distearate, polypropylene glycol dibenzoate, polypropylene glycol di-2-,6-dimethylbenzoate, polypropylene glycol di-p-tert-butylbenzoate, and polypropylene glycol dicaprate.

[0027] The polypropylene glycol used in the present invention preferably has a molecular weight of 4,000 or less from the viewpoint of dispersibility when blended into aromatic polycarbonate.

[0028] The amount of polypropylene glycol used in the present invention is 0.1 to 1 part by weight, preferably 0.15 to 0.8 parts by weight, more preferably 0.2 to 0.6 parts by weight, and even more preferably 0.25 to 0.5 parts by weight, per 100 parts by weight of the aromatic polycarbonate resin. If the amount is less than the above range, it will not be effective in suppressing yellowing due to irradiation with ionizing radiation, while if the amount is more than the above range, it will undesirably result in a decrease in mechanical properties.

[0029] <Aromatic phosphite ester-based heat stabilizer (Component D)> Examples of the aromatic phosphite ester-based heat stabilizer used in the present invention include triaryl phosphites such as triphenyl phosphite, tricresyl phosphite, tris(ethylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, tris(nonylphenyl)phosphite, and tris(hydroxyphenyl)phosphite; and arylalkyl phosphites such as phenyldidecyl phosphite, diphenylisooctyl phosphite, phenylisooctyl phosphite, and 2-ethylhexyldiphenyl phosphite. Among the aromatic phosphite ester-based heat stabilizers, tris(2,4-di-tert-butylphenyl)phosphite is preferred.

[0030] The amount of aromatic phosphite ester heat stabilizer used in the present invention is 0.01 to 0.1 part by weight, preferably 0.02 to 0.08 part by weight, more preferably 0.025 to 0.06 part by weight, and even more preferably 0.03 to 0.05 part by weight, per 100 parts by weight of aromatic polycarbonate resin. An amount less than this range is undesirable because it is ineffective in suppressing yellowing due to irradiation with ionizing radiation and results in poor molding retention stability during molding, while an amount greater than this range is undesirable because it results in a decrease in molding retention stability during molding.

[0031] <Bluing Agent (Component E)> Typical examples of the bluing agent (purple colorant) used in the present invention include Macrolex Violet B and Macrolex Blue RR manufactured by LANXESS, and Polysynthren Blue RLS manufactured by Clariant.

[0032] The blending amount of the bluing agent (purple colorant) used in the present invention is 0.00035 to 0.0005 parts by weight, preferably 0.0004 to 0.0005 parts by weight, per 100 parts by weight of the aromatic polycarbonate resin.

[0033] If the blending amount is greater than the above range, the molded article will darken and the transmission visibility will be poor. On the other hand, if the blending amount is less than the above range, the YI value after gamma ray irradiation will increase, the appearance of the molded article will turn yellow, and the visibility will be poor. If the blending amount is within the above range, it is effective in suppressing yellowing due to irradiation with ionizing radiation, and the transmission visibility of the molded article will also be good, so it is preferable.

[0034] <Release Agent (Component F)> The release agent used as needed in the present invention is blended for the purpose of improving productivity during molding and reducing distortion of molded products, and known release agents can be used. Examples include saturated fatty acid esters, unsaturated fatty acid esters, polyolefin waxes (polyethylene wax, 1-alkene polymers, etc.; those modified with functional group-containing compounds such as acid-modified waxes can also be used), silicone compounds, fluorine compounds (fluorine oils typified by polyfluoroalkyl ethers), paraffin wax, and beeswax. Among these, fatty acid esters are preferred as release agents.

[0035] Such fatty acid esters are esters of aliphatic alcohols and aliphatic carboxylic acids. Such aliphatic alcohols may be monohydric alcohols or polyhydric alcohols having dihydric or higher hydric groups. The carbon number of the alcohol is in the range of 3 to 32, more preferably 5 to 30. Examples of such monohydric alcohols include dodecanol, tetradecanol, hexadecanol, octadecanol, eicosanol, tetracosanol, ceryl alcohol, and triacontanol. Examples of such polyhydric alcohols include pentaerythritol, dipentaerythritol, tripentaerythritol, glycerol, polyglycerols (triglycerol to hexaglycerol), ditrimethylolpropane, xylitol, sorbitol, and mannitol. Polyhydric alcohols are more preferred for the fatty acid esters of the present invention.

[0036] The amount of the release agent used in the present invention is preferably 0.01 to 0.5 parts by weight, more preferably 0.03 to 0.4 parts by weight, even more preferably 0.05 to 0.3 parts by weight, and particularly preferably 0.1 to 0.2 parts by weight, per 100 parts by weight of the aromatic polycarbonate resin. Within the above range, excellent molding retention stability during molding and a good appearance of the molded product are obtained, which is preferable.

[0037] <Method for producing polycarbonate resin composition> The method for blending additives into the polycarbonate resin composition of the present invention is not particularly limited, and known methods can be used. The most commonly used method is to premix the polycarbonate resin and additives, then charge the mixture into an extruder to melt-knead, cool the extruded thread, and cut it with a pelletizer to produce a pellet-shaped molding material.

[0038] The extruder used in the above method can be either a single-screw or twin-screw extruder, but twin-screw extruders are preferred from the standpoints of productivity and kneading ability. A representative example of such a twin-screw extruder is ZSK (trade name, manufactured by Werner & Pfleiderer). Specific examples of similar types include TEX (trade name, manufactured by The Japan Steel Works, Ltd.), TEM (trade name, manufactured by Toshiba Machine Co., Ltd.), and KTX (trade name, manufactured by Kobe Steel, Ltd.). An extruder equipped with a vent capable of degassing moisture in the raw materials and volatile gases generated from the melt-kneaded resin is preferably used. A vacuum pump is preferably installed in the vent to efficiently discharge the generated moisture and volatile gases outside the extruder. A screen for removing foreign matter mixed into the extrusion raw materials can also be installed in a zone before the extruder die to remove foreign matter from the resin composition. Examples of such a screen include wire mesh, a screen changer, and a sintered metal plate (e.g., a disc filter).

[0039] Furthermore, although additives can be supplied independently to the extruder, it is preferable to premix them with the resin raw materials, as described above. Examples of such premixing means include a Nauta mixer, a V-blender, a Henschel mixer, a mechanochemical device, and an extrusion mixer. A more suitable method is to prepare a master agent by mixing a portion of the raw resin material with the additives in a high-speed mixer such as a Henschel mixer, and then mix this master agent with the remaining resin raw materials in a low-speed mixer such as a Nauta mixer.

[0040] <Molded Articles> The polycarbonate resin composition of the present invention can be molded into desired articles by known molding methods such as injection molding, blow molding, extrusion molding, and rotational molding. Molded articles formed from the polycarbonate resin composition of the present invention are extremely useful as medical products and medical components in medical devices that undergo ionizing radiation treatment. Specifically, they can be used as components for artificial dialysis machines, oxygenators, oxygenators, anesthesia inhalation devices, intravenous connectors and accessories, blood centrifuge bowls, surgical instruments, operating room instruments, and container-like packaging for these instruments, tubes for supplying oxygen to blood, tube connectors, cardiac probes, syringes, containers for intravenous injections, and the like.

[0041] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0042] The raw materials used in the following examples and comparative examples are as follows: <(A) Aromatic Polycarbonate Resin> Panlite L-1225WP manufactured by Teijin Limited (polycarbonate resin made from bisphenol A, viscosity average molecular weight 22,400) <(B) Aromatic Halogenated Polycarbonate or Oligomer> Fireguard FG-8500 manufactured by Teijin Limited (aromatic halogenated polycarbonate made from tetrabromobisphenol A, bromine content as halogen atoms 58%, number of repeating units of the formula (1) above: approximately 4) <(C) Polypropylene Glycol> Uniol D-2000 manufactured by NOF Corporation <(D) Aromatic Phosphite Heat Stabilizer> IRGAFOS168FF (tris(2,4-di-tert.butylphenyl)phosphite) manufactured by BASF <(E) Bluing Agent> Macrolex Violet B manufactured by LANXESS <(F) Mold Release Agent> Rikemal S-100A (glycerin fatty acid ester) manufactured by Riken Vitamin Co., Ltd. The evaluation methods used in the examples and comparative examples are as follows. (1) YI Pellets obtained from each composition of the examples were dried in a hot air circulation dryer at 120°C for 5 hours, and test specimens (50 mm (width) x 90 mm (length) three-stage plates with thicknesses of 1 mm, 2 mm, and 3 mm) were prepared using a J85ELIII molding machine manufactured by The Japan Steel Works, Ltd., at a cylinder temperature of 350°C and a mold temperature of 80°C. The yellowness index (YI value) of a 2 mm portion of the test specimen was measured using a CE-7000A spectrophotometer using a C2 light source and a 2-degree field of view by the transmission method. In addition, the test specimens were irradiated with cobalt-60 gamma rays at 25 kilograys (kGy) and 50 kilograys (kGy), and the YI value was measured using the method described above.

[0043] The higher the YI value of this molded plate, the more likely it is to turn yellow. After irradiation with 25 kilograys (kGy) of gamma rays, the YI value is preferably 1.0 or less, more preferably 0.5 or less. The lower limit is not particularly limited, but is preferably -5.0 or more, more preferably -4.0 or more, even more preferably -3.0 or more, and particularly preferably -2.0 or more.

[0044] Furthermore, the YI value after irradiation with 50 kilograys (kGy) of gamma rays is preferably 5.0 or less, more preferably 3.0 or less. There is no particular lower limit, but it is preferably -3.0 or more, more preferably -2.0 or more, even more preferably -1.0 or more, and particularly preferably 0 or more.

[0045] (2) Molded Plate Color (L*, a*, b*) The pellets obtained from each composition of the examples were dried in a hot air circulation dryer at 120 ° C. for 5 hours, and then molded into a molded plate having a width of 50 mm, a length of 90 mm, and a thickness of 2 mm using an injection molding machine [manufactured by The Japan Steel Works, Ltd. J85-ELIII] at a molding temperature of 350 ° C. and a mold temperature of 80 ° C. The molded plate having a thickness of 50 mm, a length of 90 mm, and a thickness of 2 mm was molded. The hue (L*, a*, b*) of this 2 mm thick molded plate was measured using an integrating sphere spectrophotometer [manufactured by X-Rite, Inc. CE-7000A] in accordance with JIS-K7105 under the conditions of a light source D65, a viewing angle of 10 degrees, and a transmission method. In addition, this 2 mm thick molded plate was irradiated with cobalt 60 gamma rays at 25 kilograys (kGy) and 50 kilograys (kGy), and then the hue (L*, a*, b*) was measured using the method described above.

[0046] The higher the L* value of this molded plate, the higher the transmittance visibility. After irradiation with 25 kilograys (kGy) of gamma rays, the L* value is preferably 93 or more, more preferably 93.5 or more. The upper limit is not particularly limited, but preferably 100 or less, 99 or less, 98 or less, 97 or less, 96 or less, or 95 or less is sufficient.

[0047] Furthermore, the L* value after irradiation with 50 kilograys (kGy) of gamma rays is preferably 93 or more, more preferably 93.5 or more. There are no particular upper limits, but preferably 100 or less, 99 or less, 98 or less, 97 or less, 96 or less, or 95 or less is sufficient. Within the above ranges, the transmittance visibility is excellent and the film appears bright.

[0048] The higher the b* value of the molded plate, the more likely the molded plate is to discolor to yellow. The b* value after irradiation with 25 kilograys (kGy) of gamma rays is preferably 1.0 or less, more preferably 0.5 or less. The lower limit is not particularly limited, but is preferably -5.0 or more, more preferably -4.0 or more, even more preferably -3.0 or more, particularly preferably -2.0 or more, and most preferably -1.0 or more.

[0049] Furthermore, the b* value after irradiation with 50 kilograys (kGy) of gamma rays is preferably 3.0 or less, and more preferably 2.0 or less. There is no particular lower limit, but it is preferably -3.0 or more, more preferably -2.0 or more, even more preferably -1.0 or more, and particularly preferably 0 or more. Within the above range, yellowing is suppressed and the appearance is excellent.

[0050] [Examples 1 to 5 and Comparative Examples 1 to 6] After blending the raw materials in the proportions shown in Table 1, the mixture was melt-kneaded at a cylinder temperature of 280°C using a vented twin-screw extruder TEX30α with a screw diameter of 30 mm, manufactured by The Japan Steel Works, Ltd., and pelletized by strand cutting. The pellets were dried at 120°C for 5 hours, and then molded into test specimens for evaluation under the conditions described above. The evaluations were carried out as described above, and the evaluation results are shown in Table 1.

[0051]

[0052] The polycarbonate resin composition of the present invention has excellent molding retention stability, minimal yellowing during ionizing radiation sterilization, and high transmittance visibility. Molded articles obtained from this polycarbonate resin composition are extremely useful as medical components for medical products and medical devices that undergo ionizing radiation treatment. Specifically, they can be used as components for artificial dialysis machines, oxygenators, oxygenators, anesthesia inhalation devices, intravenous connectors and accessories, blood centrifuge bowls, surgical instruments, operating room instruments, and container-like packaging for these instruments, tubes for supplying oxygen to blood, tube connectors, cardiac probes, syringes, and containers for intravenous injections.

Claims

1. An aromatic polycarbonate resin composition containing, per 100 parts by weight of (A) aromatic polycarbonate resin (component A), 0.5 to 3 parts by weight of (B) halogenated aromatic polycarbonate or oligomer (component B) in terms of halogen atoms, 0.1 to 1 part by weight of (C) polypropylene glycol (component C), 0.01 to 0.1 part by weight of (D) aromatic phosphite ester-based heat stabilizer (component D), and 0.00035 to 0.0005 parts by weight of (E) bluing agent (component E).

2. The polycarbonate resin composition according to claim 1, further comprising 0.01 to 0.5 parts by weight of a mold release agent (F) (Component F) per 100 parts by weight of Component A.

3. A polycarbonate resin composition according to claim 1, wherein a 2 mm thick molded plate formed from the polycarbonate resin composition has a YI of 1.0 or less after irradiating 25 kilograys (kGy) of cobalt-60 gamma rays.

4. A polycarbonate resin composition in which a 2 mm thick molded plate formed from the polycarbonate resin composition according to claim 1 has an L* value of 93 or more after irradiating 25 kilograys (kGy) of cobalt-60 gamma rays.

5. A polycarbonate resin composition in which a b* value of 1.0 or less is obtained after a 2 mm thick molded plate formed from the polycarbonate resin composition according to claim 1 is irradiated with 25 kilograys (kGy) of cobalt-60 gamma rays.

6. A molded article formed from the polycarbonate resin composition according to any one of claims 1 to 5.