Polycarbonate resin composition

Abstract

Provided is a polycarbonate resin composition which has good blocking properties with respect to light with a wavelength of 400 nm, also has excellent hue and moist heat resistance, and does not generate gas during molding. The polycarbonate resin composition is characterized by containing 0.06-0.65 part by mass of an ultraviolet absorber (B) represented by a specific structural formula and 0.005-0.70 part by mass of a phosphorus-based antioxidant (C) represented by a specific structural formula with respect to 100 parts by mass of a polycarbonate (A) having a terminal hydroxyl group content of less than 300 ppm.

Description

Polycarbonate resin composition

[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.

[0002] The eyes are constantly exposed to damage from sunlight, and it is important to protect them from ultraviolet light up to 400 nm. It has also become clear that wavelengths in the visible light range beyond ultraviolet light 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 contained in large amounts in LED light sources can cause eye diseases. For this reason, there is a need for materials that can cut out not only ultraviolet light but also light with a wavelength of 400 nm, which is closer to the visible light range.

[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 (for example, Patent Documents 1-2).

[0004] Japanese Patent Application Publication No. 09-291205 Publication No. 06-51840

[0005] However, when attempting to block 400 nm wavelength light with conventional UV absorbers as described above, the amount of absorber added becomes large, leading to the problem of increased gas generation during molding. Furthermore, even if 400 nm 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 situation, and its objective (problem) is to provide a polycarbonate resin composition that has good 400 nm wavelength light blocking ability, excellent color and humidity and heat resistance, and does not have the problem of gas generation during molding.

[0006] As a result of intensive studies to achieve the above problems, the inventors of the present invention have found that the above problems can be solved by containing a polycarbonate resin having a specific terminal hydroxyl group amount, a cyanoacrylate-based ultraviolet absorber having a specific structure, and a specific phosphorus-based antioxidant in specific amounts, respectively, and have completed the present invention. The present invention relates to the following polycarbonate resin composition.

[0007] 1. A polycarbonate resin composition comprising 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) with respect to 100 parts by mass of a polycarbonate (A) having a terminal hydroxyl group amount of less than 300 ppm. In formula (I), each R is independently C １ -C ６ an alkyl group or -(CH ２ CH ２ O) ｍ -(CH ２ ) Ｐ -CH ３ and here m is an integer of 1 to 6, p is an integer of 0 to 6, and n is 2 or 3. 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.

[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). 3. The polycarbonate resin composition according to 1 or 2 above, wherein the phosphorus-based antioxidant (C) is a compound of the following structural formula (II-1). 4. A polycarbonate resin composition according to any one of 1 to 3 above, 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 according to JIS K7105. 5. A polycarbonate resin composition according to any one of 1 to 4 above, 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, as measured according to JIS K7136, is 1.0% or less. 6. A polycarbonate resin composition according to any one of 1 to 5 above, wherein the area ratio of deposits on the mold is less than 5% when 100 shots of injection molding 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. 7. Pellets of the polycarbonate resin composition according to any one of 1 to 6 above. 8. A molded product made from the pellets described in 7 above. 9. A molded product according to 8 above, wherein the molded product is for use as an eyeglass lens.

[0009] The polycarbonate resin composition of the present invention has good light-cutting properties at a wavelength of 400 nm, excellent color and heat resistance, and does not have the problem of gas generation during molding.

[0010] This is a plan view of the teardrop-shaped mold used to evaluate gas generation during molding in the example.

[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 numerical values ​​described before and after it are included as the lower limit and upper limit.

[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 constituting 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 the polycarbonate resin, and is measured, for example, by the titanium tetrachloride / acetic acid method [Macromol. Chem. 88 215 (1965)].

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

[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; and 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, Bis(hydroxyaryl)alkanes such as 4,4-bis(4-hydroxyphenyl)heptane, 2,2-bis(4-hydroxyphenyl)nonane, 1,1-bis(4-hydroxyphenyl)decane, and 1,1-bis(4-hydroxyphenyl)dodecane;

[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, Bis(hydroxyaryl)cycloalkanes such as 1,1-bis(4-hydroxyphenyl)-4-phenylcyclohexane;

[0022] Cardo-structure-containing bisphenols such as 9,9-bis(4-hydroxyphenyl)fluorene and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene;

[0023] Dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide and 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] Examples include dihydroxydiarylsulfones such as 4,4'-dihydroxydiphenylsulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone; and so on.

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

[0027] Examples of monomers serving as raw materials for aliphatic polycarbonate resins include 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, 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, 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, spiroglycol;

[0030] aralkyl diols 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, 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, specifically, phosgene; and haloformates such as bischloroformates and monochloroformates of dihydroxy compounds.

[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, the interfacial polymerization method is preferred because it is easier to produce 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. In addition, the polycarbonate resin (A) may be a mixture of two or more polycarbonate resins with different viscosity-average molecular weights, and in this case, polycarbonate resins with viscosity-average molecular weights outside the above preferred range may 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 × 10⁻¹⁰ －４ Mv ０．８３ It refers to the value calculated from [the above]. 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.

[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 not only virgin raw material, but also polycarbonate resin recycled from used products (so-called material-recycled polycarbonate resin). However, it is preferable that the recycled polycarbonate resin accounts for 80% by mass or less of the total polycarbonate resin, and more preferably 50% by mass or less. This is because recycled polycarbonate resin is highly likely to have undergone degradation such as thermal degradation and aging degradation, and using more of such polycarbonate resin than the above range may reduce its hue and mechanical properties.

[0042] [UV absorber (B)] The polycarbonate resin composition of the present invention contains a UV absorber (B) represented by the following general formula (I). 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. In general formula (I), R is preferably C １ -C ６ The alkyl group is a methyl group, ethyl group, propyl group, n-butyl group, t-butyl group, pentyl group, or hexyl group, and more preferably a methyl group. And it is preferable that n in (OR)n is 2.

[0043] As the ultraviolet absorber (B) represented by general formula (I), the compound with the following structural formula (I-1) is preferred.

[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. Examples of other ultraviolet absorbers besides ultraviolet absorber (B) include benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, malonic acid ester-based ultraviolet absorbers, and benzoxazine-based ultraviolet 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 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] 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 antioxidants (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. Note that one phosphorus-based antioxidant (C) may be included, or two or more may be included 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, 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 other than those described above, such as antioxidants other than phosphorus-based antioxidant (C), heat stabilizers, lightfastness agents, 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, when other resins other than polycarbonate resin (A) are included, the content is preferably 40 parts by mass, 30 parts by mass or less, 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 400 nm 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 a wavelength of 400 nm makes it particularly suitable as a material for sunglass lenses and the like that aims to cut out the 400 nm 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.

[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.

[0057] (Examples 1-6, Comparative Examples 1-11) [Production 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 twin-screw extruder with a vent and screw diameter of 26.5 mm (TEX25αIII manufactured by Japan Steel Works, Ltd.), and polycarbonate resin composition 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 "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. Specifically, the metal mirror surface on the fixed side of the mold after injection molding was photographed with a Keyence digital microscope "VHX-970," and the area of ​​the obtained image was measured using Keyence image analysis software "VHX-H3MB" to calculate the area ratio of the white deposits. The range of the mold mirror surface covered was 1000 mm. ２ This is the rectangular area described below. Gas generation during molding was evaluated and judged according to the area ratio of the white deposits, based on 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 and less than 35% (50 mm) ２ More than 350mm ２ Less than (slightly inferior mold contamination resistance) C: Adhesion area ratio of 35% or more (350 mm) ２ (The above) (Severe mold contamination)

[0059] The teardrop-shaped mold shown in Figure 1 is designed to introduce the resin composition from the gate G, and to allow generated gas to easily accumulate 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 a rectangle with a short side of 27.4 mm (13.7 mm to the left and 13.7 mm to the right of the center line of the mold (the line connecting point P and the center line of the gate G)) and a long side of 36.5 mm (26.0 mm upwards and 10.5 mm downwards from the position of the 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 400nm transmittance] The obtained pellets were dried in a hot air circulation dryer at 120°C for 5 hours. Then, using an injection molding machine (Sumitomo Heavy Industries, Ltd. "SE50DUZ"), three stepped flat test specimens measuring 50 mm in width x 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 30 seconds. In accordance with JIS K7105, the transmittance at 400 nm (unit: %) was measured for the 2 mm thick portion of the stepped flat test specimen using a spectrophotometer (Shimadzu Corporation "UV-3100PC"), and judged according to the following five evaluation criteria. S: 400nm transmittance at a thickness of 2mm is less than 0.005% A: 400nm transmittance at a thickness of 2mm is 0.005% or more and less than 0.01% B: 400nm transmittance at a thickness of 2mm is 0.01% or more and less than 1.0% C: 400nm transmittance at a thickness of 2mm is 1.0% or more and less than 5.0% D: 400nm transmittance at a thickness of 2mm is 5.0% or more

[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 the following two stages, A and B. A: Total light transmittance of 89% or more at a thickness of 2 mm B: Total light transmittance of less than 89% at a thickness of 2 mm A total light transmittance of 89% or more is preferable because it indicates a superior color.

[0062] [Evaluation of Humid Heat Resistance: 50 Hours of Humid Heat Treatment] The stepped flat test specimens obtained above were subjected to 50 hours of humid heat treatment at a temperature of 121°C and a relative humidity of 100% using an advanced accelerated life test apparatus (EHS-222MD, manufactured by ESPEC). In accordance with JIS K7136, the haze (unit: %) was measured using a turbidimeter (NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.) and evaluated in three stages: A, B, and C. A: The haze value at a thickness of 2 mm after 50 hours was 1.0% or less, indicating a very small increase in haze and good humid heat resistance. B: The haze value at a thickness of 2 mm after 50 hours was greater than 1.0% but less than 95%, indicating an improvement in haze and slightly poor humid heat resistance. C: The haze value at a thickness of 2 mm after 50 hours was 95% or more, indicating a clear increase in haze and extremely poor humid heat resistance.

[0063] [Evaluation of Humid Heat Resistance: 170 Hours of Humid Heat Treatment] The stepped flat test specimens obtained above were subjected to 170 hours of humid heat treatment at a temperature of 121°C and a relative humidity of 100% using an advanced accelerated life test apparatus (EHS-222MD, manufactured by ESPEC). In accordance with JIS K7136, the haze (unit: %) was measured using a turbidimeter (NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.) and evaluated in the following four stages: A, B, C, and D. A: The haze value at 2 mm after 170 hours was 2.0% or less, indicating a very small increase in haze and good humid heat resistance. B: The haze value at 2 mm after 170 hours was greater than 2.0% but less than 5%, indicating an improvement in haze and slightly poor humid heat resistance. C: The haze value at 2 mm after 170 hours is between 5.0% and 95.0%, indicating an improvement in haze and slightly poor resistance to humidity and heat. D: The haze value at 2 mm after 170 hours is above 95.0%, indicating a clear increase in haze and extremely poor resistance to humidity and heat.

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

[0065]

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

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

[0068] [Evaluation of total transmittance in the range of 350 nm to 410 nm] For stepped flat test pieces 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") for a 2 mm thick portion of the stepped flat test piece, 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 UV shielding effect was higher when a phosphorus-based antioxidant was included.

[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 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) with respect to 100 parts by mass of a polycarbonate (A) having an end hydroxyl group content of less than 300 ppm. In the formula (I), each R is independently C １ -C ６ an alkyl group or -(CH ２ CH ２ O) ｍ -(CH ２ ) Ｐ -CH ３ and here m is an integer of 1 to 6, p is an integer of 0 to 6, and n is 2 or 3. In the 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).

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).

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