Polycarbonate resin composition

Abstract

A polycarbonate resin composition that exhibits good light-cutting properties at a wavelength of 400 nm, excellent color and heat and humidity resistance, and no gas generation problems during molding. A polycarbonate resin composition characterized by containing 0.06 to 0.65 parts by mass of an ultraviolet absorber (B) represented by a specific structural formula and 0.005 to 0.70 parts by mass of a phosphorus-based antioxidant (C) represented by a specific structural formula, per 100 parts by mass of polycarbonate (A) having a terminal hydroxyl group content of less than 300 ppm.

Description

[Technical Field]

[0001] The present invention relates to a polycarbonate resin composition, and more specifically, to a polycarbonate resin composition that has good light-cutting properties at a wavelength of 400 nm, excellent color and heat and humidity resistance, and does not have problems with gas generation during molding. [Background technology]

[0002] The eyes are constantly exposed to damage from sunlight, and it is important to protect them from ultraviolet light up to 400nm wavelength. It has also become clear that wavelengths closer to the visible light range can damage eye tissue. Furthermore, with the widespread use of devices and lighting that use LEDs as light sources, it has been reported that blue light, which is abundant in LED light sources, can cause eye diseases. Therefore, in addition to ultraviolet light, there is a need for materials that can cut out light with a wavelength of 400 nm, which is closer to the visible light spectrum.

[0003] Generally, polycarbonate resins have excellent mechanical properties, weather resistance, and transparency, and polycarbonate resin compositions containing UV absorbers are used as transparent UV-absorbing materials for eyeglasses, sunglasses, goggles, and various lighting covers. UV absorbers such as benzophenone-based, benzotriazole-based, triazine-based, and salicylate-based UV absorbers are used (see, for example, Patent Documents 1-2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 09-291205 [Patent Document 2] Special Publication No. 06-51840 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, attempting to block 400nm wavelength light with conventional UV absorbers as described above requires a large amount of the absorber, resulting in increased gas generation during molding. Furthermore, even if 400nm wavelength light can be blocked, there are issues such as poor color and inferior resistance to humidity and heat. The present invention has been made in view of the above circumstances, and its objective (problem) is to provide a polycarbonate resin composition that has good light-cutting properties at a wavelength of 400 nm, excellent color and heat and humidity resistance, and no problems with gas generation during molding. [Means for solving the problem]

[0006] The inventors of the present invention conducted extensive research to address the above issues and, as a result, discovered that the above issues can be solved by incorporating a specific amount of a cyanoacrylate-based ultraviolet absorber with a specific structure and a specific phosphorus-based antioxidant into a polycarbonate resin with a specific amount of terminal hydroxyl groups, and thus completed the present invention. This invention relates to the following polycarbonate resin compositions.

[0007] 1. A polycarbonate resin composition characterized by containing, per 100 parts by mass of polycarbonate (A) having a terminal hydroxyl group content of less than 300 ppm, 0.06 to 0.65 parts by mass of an ultraviolet absorber (B) represented by the following general formula (I), and 0.005 to 0.70 parts by mass of a phosphorus-based antioxidant (C) represented by the following general formula (II). [ka] In formula (I), each R is independently a C1-C6 alkyl group or -(CH2CH2O) m -(CH2) P -CH3, where m is an integer from 1 to 6, p is an integer from 0 to 6, and n is 2 or 3. [ka] In formula (II), R 1 , R 2 and R 3may be the same or different and each represents an aryl group having 6 to 30 carbon atoms.

[0008] 2. The polycarbonate resin composition according to 1 above, wherein the ultraviolet absorber (B) is a compound of the following structural formula (I-1).

Chemical formula

Chemical formula

Advantages of the Invention

[0009] The polycarbonate resin composition of the present invention has good cut-off properties for light with a wavelength of 400 nm, excellent color tone and heat and humidity resistance, and no problem of gas generation during molding.

Brief Description of the Drawings

[0011] The present invention will be described in detail below with reference to embodiments and examples. In this specification, unless otherwise specified, "~" means that the numbers before and after it are included as the lower and upper limits.

[0012] The polycarbonate resin composition of the present invention is characterized by containing, per 100 parts by mass of polycarbonate (A) having a terminal hydroxyl group content of less than 300 ppm, 0.06 to 0.65 parts by mass of an ultraviolet absorber (B) represented by the general formula (I), and 0.005 to 0.70 parts by mass of a phosphorus-based antioxidant (C) represented by the general formula (II). The components of the polycarbonate resin composition of the present invention will be described in detail below.

[0013] [Polycarbonate resin (A)] The polycarbonate resin (A) used in the present invention is a polycarbonate resin with a terminal OH content of less than 300 ppm. By combining such a polycarbonate resin with the ultraviolet absorber (B) represented by the general formula (I) and the phosphorus-based antioxidant (C) represented by the general formula (II), a polycarbonate resin composition can be obtained that has good light-cutting properties at a wavelength of 400 nm, excellent color and heat and humidity resistance, and no problems with gas generation during molding.

[0014] The terminal hydroxyl group concentration is expressed in ppm as the mass of terminal hydroxyl groups relative to the mass of polycarbonate resin, and is measured, for example, by the titanium tetrachloride / acetic acid method colorimetric determination [Macromol. Chem. 88 215 (1965)].

[0015] Polycarbonate resin is a polymer with a basic structure having a carbonate bond represented by the formula: -[-OXOC(=O)-]-. In the formula, X is generally a hydrocarbon, but heteroatoms and heterobonded X may be used to impart various properties. Furthermore, polycarbonate resins can be classified into aromatic polycarbonate resins, where the carbon atoms directly bonded to the carbonate bonds are aromatic carbons, and aliphatic polycarbonate resins, where the carbon atoms are aliphatic carbons. Either type can be used. Among these, aromatic polycarbonate resins are preferred from the viewpoint of heat resistance, mechanical properties, and electrical properties.

[0016] There are no specific restrictions on the type of polycarbonate resin, but examples include polycarbonate polymers obtained by reacting a dihydroxy compound with a carbonate precursor. In this case, polyhydroxy compounds may also be reacted in addition to the dihydroxy compound and carbonate precursor. Alternatively, a method may be used in which carbon dioxide is used as the carbonate precursor and reacted with a cyclic ether. Furthermore, the polycarbonate polymer may be linear or branched. In addition, the polycarbonate polymer may be a monopolymer consisting of one type of repeating unit, or a copolymer having two or more types of repeating units. In this case, various copolymerization forms such as random copolymers and block copolymers can be selected. Typically, such polycarbonate polymers are thermoplastic resins.

[0017] Examples of aromatic dihydroxy compounds among the monomers used as raw materials for aromatic polycarbonate resins include: Dihydroxybenzenes such as 1,2-dihydroxybenzene, 1,3-dihydroxybenzene (i.e., resorcinol), and 1,4-dihydroxybenzene; Dihydroxybiphenyls such as 2,5-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, and 4,4'-dihydroxybiphenyl;

[0018] Dihydroxynaphthalene compounds such as 2,2'-dihydroxy-1,1'-binaphthyl, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, and 2,7-dihydroxynaphthalene;

[0019] Dihydroxydiaryl ethers such as 2,2'-dihydroxydiphenyl ether, 3,3'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 1,4-bis(3-hydroxyphenoxy)benzene, and 1,3-bis(4-hydroxyphenoxy)benzene;

[0020] 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 1,1-Bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(3-methoxy-4-hydroxyphenyl)propane, 1,1-Bis(3-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-Bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(3-cyclohexyl-4-hydroxyphenyl)propane, α,α'-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, Bis(4-hydroxyphenyl)methane, Bis(4-hydroxyphenyl)cyclohexylmethane, Bis(4-hydroxyphenyl)phenylmethane, Bis(4-hydroxyphenyl)(4-propenylphenyl)methane, Bis(4-hydroxyphenyl)diphenylmethane, Bis(4-hydroxyphenyl)naphthylmethane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)-1-naphthylethane, 1,1-Bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 1,1-Bis(4-hydroxyphenyl)hexane, 2,2-bis(4-hydroxyphenyl)hexane, 1,1-Bis(4-hydroxyphenyl)octane, 2,2-bis(4-hydroxyphenyl)octane, 4,4-bis(4-hydroxyphenyl)heptane, 2,2-bis(4-hydroxyphenyl)nonane, 1,1-bis(4-hydroxyphenyl)decane, 1,1-Bis(4-hydroxyphenyl)dodecane, Bis(hydroxyaryl)alkanes such as;

[0021] 1,1-Bis(4-hydroxyphenyl)cyclopentane, 1,1-Bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,4-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,5-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-Bis(4-hydroxy-3,5-dimethylphenyl)-3,3,5-trimethylcyclohexane, 1,1-Bis(4-hydroxyphenyl)-3-propyl-5-methylcyclohexane, 1,1-Bis(4-hydroxyphenyl)-3-tert-butyl-cyclohexane, 1,1-Bis(4-hydroxyphenyl)-4-tert-butyl-cyclohexane, 1,1-bis(4-hydroxyphenyl)-3-phenylcyclohexane, 1,1-Bis(4-hydroxyphenyl)-4-phenylcyclohexane, Bis(hydroxyaryl)cycloalkanes such as;

[0022] 9,9-Bis(4-hydroxyphenyl)fluorene, Bisphenols containing cardo structures, such as 9,9-bis(4-hydroxy-3-methylphenyl)fluorene;

[0023] 4,4'-Dihydroxydiphenyl sulfide, Dihydroxydiaryl sulfides such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide;

[0024] Dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide;

[0025] 4,4'-Dihydroxydiphenylsulfone, Dihydroxydiarylsulfones such as 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone; These are some examples.

[0026] Among these, bis(hydroxyaryl)alkanes are preferred, and among them, bis(4-hydroxyphenyl)alkanes are preferred, and in particular, 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A) is preferred from the viewpoint of impact resistance and heat resistance. Furthermore, one aromatic dihydroxy compound may be used, or two or more may be used in any combination and ratio.

[0027] Furthermore, to give an example of monomers that are raw materials for aliphatic polycarbonate resins, Alkanediols such as ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 2-methyl-2-propylpropane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, and decane-1,10-diol;

[0028] Cycloalkanediols such as cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol, 1,4-cyclohexanedimethanol, 4-(2-hydroxyethyl)cyclohexanol, and 2,2,4,4-tetramethyl-cyclobutane-1,3-diol;

[0029] Glycols such as ethylene glycol, 2,2'-oxydiethanol (i.e., diethylene glycol), triethylene glycol, propylene glycol, and spiroglycol;

[0030] Aralkyldiols such as 1,2-benzenedimethanol, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 1,4-benzenediethanol, 1,3-bis(2-hydroxyethoxy)benzene, 1,4-bis(2-hydroxyethoxy)benzene, 2,3-bis(hydroxymethyl)naphthalene, 1,6-bis(hydroxyethoxy)naphthalene, 4,4'-biphenyldimethanol, 4,4'-biphenyldiethanol, 1,4-bis(2-hydroxyethoxy)biphenyl, bisphenol A bis(2-hydroxyethyl) ether, and bisphenol S bis(2-hydroxyethyl) ether;

[0031] Examples include cyclic ethers such as 1,2-epoxyethane (i.e., ethylene oxide), 1,2-epoxypropane (i.e., propylene oxide), 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,4-epoxycyclohexane, 1-methyl-1,2-epoxycyclohexane, 2,3-epoxynorbornane, and 1,3-epoxypropane.

[0032] Among the monomers used as raw materials for polycarbonate resin, examples of carbonate precursors include carbonyl halides and carbonate esters. Note that one type of carbonate precursor may be used, or two or more types may be used in any combination and ratio.

[0033] Examples of carbonyl halides include, for example, phosgene; bischloroformates of dihydroxy compounds; monochloroformates of dihydroxy compounds; and other haloformates.

[0034] Examples of carbonate esters include diaryl carbonates such as diphenyl carbonate and dityl carbonate; dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; and carbonates of dihydroxy compounds such as biscarbonates, monocarbonates, and cyclic carbonates of dihydroxy compounds.

[0035] The method for producing polycarbonate resin is not particularly limited, and any method can be used. Examples include interfacial polymerization, molten transesterification, pyridine method, ring-opening polymerization of cyclic carbonate compounds, and solid-phase transesterification of prepolymers.

[0036] The amount of terminal hydroxyl groups in polycarbonate resin (A) is less than 300 ppm, preferably 250 ppm or less, more preferably 200 ppm or less, even more preferably 170 ppm or less, preferably 30 ppm or more, more preferably 50 ppm or more, and even more preferably 70 ppm or more. Among the above-mentioned manufacturing methods for polycarbonate resin (A), the interfacial polymerization method is preferred because it is easy to produce a polycarbonate resin (A) with a terminal hydroxyl group amount of less than 300 ppm.

[0037] The molecular weight of the polycarbonate resin (A) is preferably in the range of 16,000 to 50,000 in viscosity-average molecular weight (Mv), more preferably 18,000 or more, even more preferably 20,000 or more, more preferably 45,000 or less, even more preferably 40,000 or less, and particularly preferably 38,000 or less. If the viscosity-average molecular weight is less than 16,000, the impact resistance of the molded product tends to decrease and cracking may occur, which is undesirable. If it is greater than 50,000, the fluidity will be poor and problems with moldability are likely to occur, which is also undesirable. Furthermore, the polycarbonate resin (A) may be a mixture of two or more polycarbonate resins with different viscosity-average molecular weights. In this case, polycarbonate resins whose viscosity-average molecular weight is outside the above preferred range may also be mixed.

[0038] In this invention, the viscosity-average molecular weight [Mv] of the polycarbonate resin is determined by using methylene chloride as the solvent, calculating the intrinsic viscosity [η] (unit: dl / g) at 25°C using an Ubbelohde viscometer, and then using Schnell's viscosity formula, i.e., η = 1.23 × 10 -4 Mv 0.83It refers to the value calculated from [η]. Intrinsic viscosity [η] is the specific viscosity [η] at each solution concentration [C] (g / dl). sp This value was calculated by measuring [the value] and using the following formula.

number

[0039] Furthermore, in the present invention, polycarbonate resin may be used in combination with other thermoplastic resins. In addition, for example, to further enhance flame retardancy and impact resistance, the polycarbonate resin may be configured as a copolymer mainly composed of polycarbonate resin, such as: a copolymer with an oligomer or polymer having a siloxane structure; a copolymer with a monomer, oligomer or polymer having a phosphorus atom to further improve thermal oxidation stability and flame retardancy; a copolymer with a monomer, oligomer or polymer having a dihydroxyanthraquinone structure to improve thermal oxidation stability; a copolymer with an oligomer or polymer having an olefin-based structure such as polystyrene to improve optical properties; or a copolymer with a polyester resin oligomer or polymer to improve chemical resistance.

[0040] Furthermore, in order to improve the appearance and fluidity of the molded product, the polycarbonate resin may contain polycarbonate oligomers. The viscosity-average molecular weight (Mv) of these polycarbonate oligomers is usually 1500 or more, preferably 2000 or more, and usually 9500 or less, preferably 9000 or less. Moreover, it is preferable that the amount of polycarbonate oligomers contained be 30% by mass or less of the polycarbonate resin (including the polycarbonate oligomers).

[0041] Furthermore, the polycarbonate resin may be made not only from virgin raw materials, but also from recycled polycarbonate resin made from used products (so-called material-recycled polycarbonate resin). However, the recycled polycarbonate resin preferably accounts for 80% by mass or less, more preferably 50% by mass or less, of the polycarbonate resin. Since the recycled polycarbonate resin is likely to have undergone deterioration such as thermal degradation and aging degradation, if such polycarbonate resin is used in an amount exceeding the above range, it may reduce the hue and mechanical properties.

[0042] [Ultraviolet absorber (B)] The polycarbonate resin composition of the present invention contains an ultraviolet absorber (B) represented by the following general formula (I). [Chemical formula] In formula (I), each R is independently a C1-C6 alkyl group or -(CH2CH2O) m -(CH2) P -CH3, where m is an integer from 1 to 6, p is an integer from 0 to 6, and n is 2 or 3. R in general formula (I) is preferably a C1-C6 alkyl group, which is a methyl group, an ethyl group, a propyl group, an n-butyl group, a t-butyl group, a pentyl group, a hexyl group, and more preferably a methyl group. And n in (OR)n is preferably 2.

[0043] As the ultraviolet absorber (B) represented by general formula (I), the compound of the following structural formula (I-1) is preferably mentioned. [Chemical formula]

[0044] The content of the ultraviolet absorber (B) is 0.06 to 0.65 parts by mass per 100 parts by mass of polycarbonate resin (A). If the content is less than 0.06 parts by mass, the transmittance of the resulting resin composition in the 400 nm wavelength range becomes too high, and if it exceeds 0.65 parts by mass, the transmittance in the 400 nm wavelength range becomes low, but gas generation during molding becomes significant, and volatile components adhere to the molded product, making it easy to impair the product's appearance. The content of the ultraviolet absorber (B) is preferably 0.07 parts by mass or more, more preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, 0.25 parts by mass or more, 0.3 parts by mass or more, 0.4 parts by mass or more, and especially preferably 0.5 parts by mass or more, and preferably 0.6 parts by mass or less, per 100 parts by mass of polycarbonate resin (A).

[0045] The polycarbonate resin composition of the present invention does not exclude the inclusion of other ultraviolet absorbers in small amounts besides the ultraviolet absorber (B) described above. However, even when other ultraviolet absorbers are included, their content is preferably less than 0.1 parts by mass, more preferably less than 0.05 parts by mass, less than 0.003 parts by mass, less than 0.002 parts by mass, less than 0.001 parts by mass, and especially less than 0.0005 parts by mass per 100 parts by mass of polycarbonate resin (A). It is most preferable that they are substantially absent, which specifically means less than 0.0001 parts by mass. Other UV absorbers besides UV absorber (B) include, for example, benzotriazole-based UV absorbers, triazine-based UV absorbers, malonic acid ester-based UV absorbers, and benzoxazine-based UV absorbers.

[0046] [Stabilizer (C)] The polycarbonate resin composition of the present invention contains a phosphorus-based antioxidant (C) represented by the following general formula (II) in an amount of 0.005 to 0.70 parts by mass in combination with the above-mentioned ultraviolet absorber (B). By combining the ultraviolet absorber (B) in such an amount with the aforementioned content, it is possible to achieve good light blocking properties at a wavelength of 400 nm, excellent color and heat resistance, and to eliminate the problem of gas generation during molding.

[0047] [ka] In formula (II), R 1 , R 2 and R 3 These may be the same or different, and are aryl groups having 6 to 30 carbon atoms. Preferably, the aryl groups are phenyl, nonylphenyl, and tert-butylphenyl, with tert-butylphenyl being particularly preferred.

[0048] Among the phosphorus-based antioxidant (C) represented by the above formula (II), triphenyl phosphite, tris(mononylphenyl) phosphite, and tris(2,4-di-tert-butylphenyl) phosphite are preferred, with tris(2,4-di-tert-butylphenyl) phosphite being more preferred. Furthermore, the phosphorus-based antioxidant (C) may contain one type, or two or more types may be contained in any combination and ratio.

[0049] The content of the phosphorus-based antioxidant (C) is 0.005 to 0.70 parts by mass per 100 parts by mass of polycarbonate resin (A), preferably 0.007 parts by mass or more, more preferably 0.008 parts by mass or more, and also preferably 0.60 parts by mass or less, more preferably 0.50 parts by mass or less, and among these, 0.40 parts by mass or less, 0.30 parts by mass or less, 0.20 parts by mass or less, and particularly preferably 0.15 parts by mass or less. If the content of the phosphorus-based antioxidant (C) is less than 0.005 parts by mass, the hue and heat discoloration resistance will be insufficient, and if it exceeds 0.70 parts by mass, not only will the heat discoloration resistance worsen, but the moist heat stability will also decrease, and it may also cause gas generation during molding.

[0050] [Additives, etc.] The polycarbonate resin composition of the present invention may contain other additives besides those mentioned above, such as antioxidants other than phosphorus-based antioxidants (C), heat stabilizers, lightfasteners, weather resistance modifiers, mold release agents, fluorescent whitening agents, pigments, dyes, flame retardants, impact resistance modifiers, antistatic agents, plasticizers, compatibilizers, and other resins other than polycarbonate resin. These additives or other resins may be blended one or more types. However, if other resins are included besides polycarbonate resin (A), the content is preferably 40 parts by mass, 30 parts by mass or less, or 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less, per 100 parts by mass of polycarbonate resin (A).

[0051] [Method for producing polycarbonate resin composition] There are no limitations on the method for producing the polycarbonate resin composition of the present invention, and a wide range of known methods for producing polycarbonate resin compositions can be employed. For example, a method may be used in which polycarbonate resin (A), an ultraviolet absorber (B), a phosphorus-based antioxidant (C), and other components that may be added as needed are pre-mixed using various mixers such as a tumbler or a Henschel mixer, and then melt-kneaded using a mixer such as a Banbury mixer, roll, braver, single-screw extruder, twin-screw extruder, or kneader. The melt-kneading temperature is not particularly limited, but is usually in the range of 240 to 320°C.

[0052] The polycarbonate resin composition of the present invention can be used to produce various molded products by molding pellets obtained by pelletizing the above-described polycarbonate resin composition using various molding methods. Alternatively, the resin, which is melt-kneaded in an extruder, can be directly molded into molded products without going through pellets.

[0053] The polycarbonate resin composition of the present invention exhibits excellent cut performance in the 400nm wavelength range. Therefore, in a molded article with a thickness of 2 mm obtained by molding this polycarbonate resin composition, the transmittance measured at a wavelength of 400 nm in accordance with JIS K7105 is preferably 2% or less, more preferably 1.5% or less, and even more preferably less than 1.0%. A transmittance of less than 1.0% at 400 nm makes it particularly suitable as a material for sunglass lenses and the like that aims to cut out the 400nm wavelength range.

[0054] Molded articles obtained from the polycarbonate resin composition of the present invention exhibit good light-cutting properties at a wavelength of 400 nm, excellent color and heat and humidity resistance, and no problems with gas generation during molding. Therefore, preferred applications include eyeglass lenses, such as sunglass lenses, computer safety glasses lenses, goggles, safety glasses, and face shields. [Examples]

[0055] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples.

[0056] The raw materials and evaluation methods used in the following examples and comparative examples are as follows. [Table 1]

[0057] (Examples 1-6, Comparative Examples 1-11) [Manufacturing of resin composition pellets] Each component listed in Table 1 above was blended in the proportions (parts by mass) shown in Table 2 below, mixed in a tumbler for 20 minutes, and then melt-kneaded at a cylinder temperature of 270°C using a vented twin-screw extruder with a screw diameter of 26.5 mm (TEX25αIII, manufactured by Japan Steel Works, Ltd.), and polycarbonate resin pellets were obtained by strand cutting.

[0058] [Evaluation of gas generation during molding] The pellets obtained above were dried at 120°C for 5 hours. Then, using an injection molding machine (Sumitomo Heavy Industries, Ltd. "SE7M"), 100 shots were injection molded using the teardrop-shaped mold shown in Figure 1, under the conditions of a cylinder temperature of 320°C, a molding cycle of 10 seconds, and a mold temperature of 40°C. After completion, the condition of the white deposits that formed on the metal mirror surface on the fixed side of the mold was evaluated by calculating the area ratio of the white deposits using the following method, and the gas generation during molding was assessed. Specifically, the metal mirror surface on the fixed side of the mold after injection molding was photographed using a Keyence VHX-970 digital microscope. The obtained images were then analyzed using Keyence VHX-H3MB image analysis software to measure the area and calculate the area ratio of the white deposits. The target area of ​​the mold mirror surface was 1000 mm². 2 This is the area of ​​the rectangle described below. The gas generation during molding was evaluated and determined based on the area percentage of the white deposits, according to the following criteria. A: Adhesion area ratio is less than 5% (50 mm) (mold contamination resistance is extremely good) B: Adhesion area ratio is 5% or more but less than 35% (50mm 2 More than ~350mm 2 (Less than) (Slightly inferior mold contamination resistance) C: Adhesion area ratio of 35% or more (350mm 2 (The above) (Severe mold contamination)

[0059] The teardrop-shaped mold shown in Figure 1 is designed to allow the resin composition to be introduced from the gate G, and to facilitate the accumulation of generated gas at the tip P. The gate G has a width of 1 mm and a thickness of 1 mm. In Figure 1, the maximum width h1 of the teardrop shape is 14.5 mm, the length h2 is 7.0 mm, the length h3 is 27.0 mm, and the thickness of the molded part is 3 mm. The rectangular area measured is defined as follows, as shown in Figure 1: the shorter side is 27.4 mm, with 13.7 mm extending to the left and right from the center line of the mold (the line connecting point P and the center line of gate G), and the longer side is 36.5 mm, with 26.0 mm extending upwards and 10.5 mm extending downwards from the point of maximum width of the teardrop shape (area: 36.5 mm × 27.4 mm = 1000.1 mm²). 2 The area of ​​the white deposits within this rectangle was measured using the method described above, and its area percentage (%) was calculated.

[0060] [Measurement of transmittance at 400nm] The obtained pellets were dried at 120°C for 5 hours in a hot air circulation dryer. Then, using an injection molding machine (Sumitomo Heavy Industries, Ltd. "SE50DUZ"), three stepped flat test pieces measuring 50 mm in width and 90 mm in length with thicknesses of 1 mm, 2 mm, and 3 mm were molded under the conditions of resin temperature 280°C, mold temperature 80°C, and molding cycle of 30 seconds. In accordance with JIS K7105, the transmittance (in %) at 400 nm was measured for a 2 mm thick portion of a stepped flat test specimen using a spectrophotometer (Shimadzu Corporation "UV-3100PC"), and the results were evaluated according to the following five-level evaluation criteria. S: Transmittance at 400nm with a thickness of 2mm is less than 0.005% A: The transmittance at 400nm with a thickness of 2mm is between 0.005% and less than 0.01%. B: Transmittance at 400nm with a thickness of 2mm is between 0.01% and less than 1.0%. C: 400nm transmittance at a thickness of 2mm is between 1.0% and less than 5.0%. D: 400nm transmittance of 5.0% or higher at a thickness of 2mm.

[0061] [Evaluation of color (total light transmittance)] For the 2 mm thick portion of the stepped flat test piece obtained above, the total light transmittance (unit: %) was measured using a turbidimeter (NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.), and the color was evaluated in two stages, A and B, as described below. A: Total light transmittance of 89% or more at a thickness of 2mm. B: Total light transmittance of less than 89% at a thickness of 2mm A total light transmittance of 89% or higher is preferable because it results in superior color reproduction.

[0062] [Evaluation of resistance to humid and heat: 50 hours of humid heat treatment] The stepped flat test specimens obtained above were subjected to 50 hours of moist heat treatment in an accelerated life testing apparatus (ESPEC "EHS-222MD") at a temperature of 121°C and a relative humidity of 100%. In accordance with JIS K7136, the haze (unit: %) was measured using a turbidimeter (Nippon Denshoku Industries Co., Ltd. "NDH-2000") and evaluated on a three-level scale of A, B, and C. A: After 50 hours, the haze value at a thickness of 2 mm was 1.0% or less, indicating that the increase in haze was extremely small and that the moisture and heat resistance was good. B: After 50 hours, the haze value at a thickness of 2 mm was between 1.0% and 95%, indicating improved haze, but slightly worse heat and humidity resistance. C: After 50 hours, the haze value at a thickness of 2 mm was over 95%, indicating a clear increase in haze, and thus the moisture and heat resistance is judged to be extremely poor.

[0063] [Evaluation of moisture and heat resistance: 170 hours of moist heat treatment] The stepped flat test specimens obtained above were subjected to 170 hours of moist heat treatment in an accelerated life testing apparatus (ESPEC "EHS-222MD") at a temperature of 121°C and a relative humidity of 100%. In accordance with JIS K7136, the haze (unit: %) was measured using a turbidimeter (Nippon Denshoku Industries "NDH-2000") and evaluated on a four-point scale: A, B, C, and D. A: The haze value at 2mm after 170 hours was 2.0% or less, indicating very little increase in haze, and thus good resistance to humidity and heat. B: After 170 hours, the haze value at 2mm was between 2.0% and 5%, indicating an improvement in haze, but also a slightly worse assessment of moisture and heat resistance. C: After 170 hours, the haze value at 2mm was between 5.0% and 95.0%, indicating an improvement in haze, but slightly worsening of moisture and heat resistance. D: After 170 hours, the haze value at 2mm was over 95.0%, indicating a clear increase in haze, and thus the moisture and heat resistance is judged to be extremely poor.

[0064] The evaluation results are shown in Table 2 below.

[0065] [Table 2]

[0066] [Evaluation of thermal aging test] Stepped flat test pieces obtained from pellets in Example 1 and Comparative Example 10 were placed in an oven at 130°C for 1000 hours, and the YI (Yield Inclusion) value was measured after testing in a 2 mm thick portion according to ASTM E313. The YI value for Example 1 was 9.1, and the YI value for Comparative Example 10 was 12.1, indicating that polycarbonate with fewer terminal hydroxyl groups was less prone to yellowing after heat aging.

[0067] [Evaluation of weather resistance test] Stepped flat test pieces obtained from pellets of Example 1 and Comparative Example 10 were subjected to a 500-hour weathering test according to ASTM G155-1, and the YI value after the test was measured according to ASTM E313 for the 2 mm thick portion. The YI value for Example 1 was 1.7, and the YI value for Comparative Example 10 was 3.5, indicating that polycarbonates with fewer terminal hydroxyl groups were less prone to yellowing in the weathering test.

[0068] [Evaluation of total transmittance in the 350nm to 410nm range] For the stepped flat test specimens obtained from the pellets of Example 1 and Comparative Example 1, the transmittance (unit: %) from 350 nm to 410 nm was measured at 1 nm intervals using a spectrophotometer (Shimadzu Corporation "UV-3100PC") in the 2 mm thick portion of the stepped flat test specimen, in accordance with JIS K7105, and the sum of the transmittances was calculated. The total transmittance for Example 1 was 1.7%, and the total transmittance for Comparative Example 1 was 2.3%, indicating that the presence of a phosphorus-based antioxidant resulted in a higher shielding effect of the ultraviolet absorber. [Industrial applicability]

[0069] Molded articles obtained from the polycarbonate resin composition of the present invention exhibit good light-cutting properties at a wavelength of 400 nm, excellent color and heat resistance, and no gas generation problems during molding. Therefore, they can be suitably used in various optical applications and have high industrial applicability.

Claims

1. A polycarbonate resin composition characterized by containing, per 100 parts by mass of aromatic polycarbonate (A) having a terminal hydroxyl group content of less than 300 ppm, 0.06 to 0.65 parts by mass of an ultraviolet absorber (B) represented by the following general formula (I), and 0.005 to 0.70 parts by mass of a phosphorus-based antioxidant (C) represented by the following general formula (II). 【Chemistry 1】 In equation (I), each R is independently C １ -C ６ Alkyl alkyl group or -(CH ２ CH ２ O) ｍ - (CH ２ ) Ｐ -CH ３ Here, m is an integer from 1 to 6, p is an integer from 0 to 6, and n is 2 or 3. 【Chemistry 2】 In formula (II), R １ , R ２ and R ３ may be the same or different and each represents an aryl group having 6 to 30 carbon atoms.

2. The polycarbonate resin composition according to claim 1, wherein the ultraviolet absorber (B) is a compound having the following structural formula (I-1). 【Transformation 3】

3. The polycarbonate resin composition according to claim 1 or 2, wherein the phosphorus-based antioxidant (C) is a compound having the following structural formula (II-1). 【Chemistry 4】

4. A polycarbonate resin composition according to claim 1 or 2, wherein a molded product with a thickness of 2 mm has a transmittance of less than 1.0% at a wavelength of 400 nm, as measured in accordance with JIS K7105.

5. A polycarbonate resin composition according to claim 1 or 2, wherein a molded product with a thickness of 2 mm is exposed to 121°C and 100% relative humidity for 50 hours, and the increase in haze value measured according to JIS K7136 is 1.0% or less.

6. The polycarbonate resin composition according to claim 1 or 2, wherein the area ratio of deposits on the mold when 100 injection moldings are performed using a teardrop-shaped mold under the conditions of a cylinder temperature of 320°C, a molding cycle of 10 seconds, and a mold temperature of 40°C is less than 5%.

7. Pellets of the polycarbonate resin composition according to claim 1 or 2.

8. A molded article comprising the pellets described in claim 7.

9. The molded article according to claim 8, wherein the molded article is for use as an eyeglass lens.

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