Resin composition, pellets, and molded article

Abstract

Disclosed is a resin composition which contains a first polycarbonate resin, a second polycarbonate resin, and a styrene-based resin, wherein: the refractive index of the first polycarbonate resin, the refractive index of the second polycarbonate resin, and the refractive index of the styrene-based resin satisfy the relational expression: (refractive index of first polycarbonate resin) < (refractive index of styrene-based resin) < (refractive index of second polycarbonate resin); and when the resin composition is molded into an article that has a thickness of 3 mm, the haze thereof is less than 20%. Also disclosed are pellets which use the resin composition, and a molded article.

Description

Resin composition, pellets, and molded products

[0001] The present invention relates to a resin composition, a pellet, and a molded article, and more particularly to a resin composition containing a polycarbonate resin and a styrene-based resin as main components.

[0002] Polycarbonate resins are widely used in various fields due to their excellent impact resistance, heat resistance, electrical insulation, dimensional stability, and other properties, with a good balance of these properties. In particular, polycarbonate resins made from bisphenol compounds have the advantages of excellent transparency, impact resistance, and heat resistance, as well as being light and shatter-resistant, and are therefore used as a glass substitute for automotive parts, building materials, and optical components such as lenses. In recent years, they have also been widely used as panel components for display devices used in various mobile terminals such as smartphones, tablet computers, car navigation systems, car audio systems, portable game consoles, digital cameras, and the like, particularly as front components for touch panels and the like.

[0003] When using a resin as an optical component, birefringence is an important optical property to consider, in addition to transparency. Even if a resin has excellent transparency, it is undesirable for it to have high birefringence. In particular, in cameras, various display devices such as liquid crystal display panels, projectors, etc., the presence of an optical component with high birefringence in the optical path has a negative effect on image quality and signal reading performance, so there is a strong demand for transparent resins with as little birefringence as possible.

[0004] Ordinary polycarbonate resins have large birefringence, but when used as a front surface member for a display device, for example, large birefringence causes phase difference, resulting in rainbow patterns, and when viewing the screen through polarized sunglasses, the rainbow patterns become even more severe, making them impossible to see, resulting in problems of reduced visibility and significantly reduced design (appearance). Polycarbonate resins made from general-purpose bisphenol A tend to have large birefringence.

[0005] Various methods have been studied to reduce the birefringence of polycarbonate resins, and it is known to use polycarbonate resins in which the resin itself contains a bisphenol having a specific structure. For example, Patent Document 1 discloses that a special polycarbonate copolymer in which spirobisindane bisphenol is copolymerized with bisphenol A has low birefringence.

[0006] Patent Document 2 proposes that a resin composition obtained by blending a styrene-maleic anhydride-N-phenylmaleimide copolymer resin (A) and an acrylonitrile-styrene copolymer resin (B) in a ratio of 37 to 47% of resin (A), 13 to 23% of resin (B), and 35 to 45% of polycarbonate resin provides a resin composition with high heat resistance, high transparency, and low birefringence.

[0007] JP 06-313035 A JP 2013-107933 A

[0008] However, when using a special resin such as that described in Patent Document 1, its use is limited in terms of cost. On the other hand, the resin composition described in Patent Document 2 has low birefringence, but its transparency is insufficient and its haze value is high. The present invention aims to solve these problems and to provide a resin composition, pellets, and molded articles having low retardation and excellent transparency.

[0009] In light of the above-mentioned problems, the present inventors conducted research and found that the above-mentioned problems can be solved by blending two or more polycarbonate resins and a styrene-based resin having a specific relationship to reduce the difference in refractive index between the polycarbonate resin and the styrene-based resin. Specifically, the above-mentioned problems were solved by the following means. <1> A resin composition containing a first polycarbonate resin, a second polycarbonate resin, and a styrene-based resin, wherein the refractive indexes of the first polycarbonate resin, the second polycarbonate resin, and the styrene-based resin satisfy the following relationship: refractive index of the first polycarbonate resin < refractive index of the styrene-based resin < refractive index of the second polycarbonate resin; and the resin composition has a haze of less than 20% when molded to a thickness of 3 mm. <2> The resin composition according to <1>, comprising 5 to 100 parts by mass of a styrene-based resin per 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin. <3> The resin composition according to <1> or <2>, wherein the refractive index of the first polycarbonate resin is 1.570 or more and less than 1.590. <4> The resin composition according to any one of <1> to <3>, wherein the first polycarbonate resin comprises a bisphenol A type aromatic polycarbonate resin. <5> The resin composition according to any one of <1> to <4>, wherein the refractive index of the second polycarbonate resin is 1.590 to 1.700. <6> The resin composition according to any one of <1> to <5>, wherein the second polycarbonate resin comprises a bisphenol AP type aromatic polycarbonate resin. <7> The resin composition according to any one of <1> to <6>, wherein the second polycarbonate resin comprises a fluorene polycarbonate resin. <8> The resin composition according to any one of <1> to <7>, wherein the refractive index of the styrene-based resin is 1.571 to 1.699. <9> The resin composition according to any one of <1> to <8>, wherein the styrene-based resin includes at least one of a styrene-based resin in which more than 90 mass% of all monomer units are styrene-based monomer units, and a styrene-based resin containing 20 to 90 mass% of styrene-based monomer units, 1 to 30 mass% of maleic anhydride monomer units, and 0 to 60 mass% of N-phenylmaleimide monomer units.<10> The resin composition according to any one of <1> to <9>, wherein the styrene-based resin is a styrene-based resin in which more than 90 mass% of all monomer units are styrene-based monomer units. <11> The resin composition according to any one of <1> to <10>, comprising 50 to 97 parts by mass of the first polycarbonate resin and 3 to 50 parts by mass of the second polycarbonate resin, per 100 parts by mass of the first polycarbonate resin and the second polycarbonate resin together. <12> The resin composition according to any one of <1> to <11>, wherein the content of the styrene-based resin is 90 parts by mass or less, per 100 parts by mass of the first polycarbonate resin and the second polycarbonate resin together, and the refractive index of the second polycarbonate resin is 1.590 to 1.700. <13> The resin composition according to any one of <1> to <12>, wherein the content of the styrene-based resin is 90 parts by mass or less per 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin, and the styrene-based resin is a styrene-based resin in which more than 90 mass% of all monomer units are styrene-based monomers. <14> The resin composition according to any one of <1> to <13>, comprising 5 to 100 parts by mass of a styrene-based resin relative to 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin, wherein the first polycarbonate resin has a refractive index of 1.570 or more and less than 1.590, wherein the first polycarbonate resin comprises a bisphenol A type aromatic polycarbonate resin, wherein the second polycarbonate resin has a refractive index of 1.590 to 1.700, wherein the second polycarbonate resin comprises a bisphenol AP type aromatic polycarbonate resin and / or a fluorene polycarbonate resin, wherein the refractive index of the styrene-based resin is 1.571 to 1.699, and wherein more than 90% by mass of all monomer units are styrene-based monomer units.<15> A resin composition comprising 5 to 100 parts by mass of a styrene-based resin relative to 100 parts by mass of a total of 50 to 97 parts by mass of a first polycarbonate resin and 3 to 50 parts by mass of a second polycarbonate resin, wherein the first polycarbonate resin comprises a bisphenol A type aromatic polycarbonate resin, and the second polycarbonate resin comprises a bisphenol AP type aromatic polycarbonate resin and / or a fluorene polycarbonate resin, and the styrene-based resin comprises at least one of a styrene-based resin having more than 90% by mass of all monomer units as a styrene-based monomer, and a styrene-based resin containing 20 to 90% by mass of styrene-based monomer units, 1 to 30% by mass of maleic anhydride monomer units, and 0 to 60% by mass of N-phenylmaleimide monomer units, and wherein the resin composition has a haze of less than 20% when molded to a thickness of 3 mm. <16> Pellets of the resin composition according to any one of <1> to <15>. <17> A molded article formed from the resin composition according to any one of <1> to <15>. <18> A molded article formed from the pellets according to <16>. <19> A lens formed from the resin composition according to any one of <1> to <15>. <20> A lens molded from the pellets according to <16>.

[0010] The present invention makes it possible to provide a resin composition, pellets, and molded articles that have low retardation and excellent transparency.

[0011] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment. Note that in this specification, the word "to" is used to mean that the numerical values ​​written before and after it are included as lower and upper limits. In this specification, various physical property values ​​and characteristic values ​​are those at 23°C unless otherwise specified. When the measurement methods etc. described in the standards shown in this specification vary depending on the fiscal year, they are based on the standards as of January 1, 2023, unless otherwise specified.

[0012] The resin composition of this embodiment is a resin composition containing a first polycarbonate resin, a second polycarbonate resin, and a styrene-based resin, wherein the refractive indexes of the first polycarbonate resin, the second polycarbonate resin, and the styrene-based resin satisfy the following relationship: refractive index of the first polycarbonate resin < refractive index of the styrene-based resin < refractive index of the second polycarbonate resin, and the haze of the resin composition when molded to a thickness of 3 mm is less than 20%. By using this configuration, a resin composition can be obtained that can provide molded products with low retardation and excellent transparency.

[0013] Retardation occurs due to the difference in refractive index between two intrinsic polarized light. Because polycarbonate resin has positive birefringence, blending a material with a negative birefringence opposite to that of polycarbonate resin can reduce retardation. In this embodiment, a styrene-based resin is blended with a polycarbonate resin so that the refractive indices of the first polycarbonate resin, the second polycarbonate resin, and the styrene-based resin satisfy the following relationship: refractive index of the first polycarbonate resin < refractive index of the styrene-based resin < refractive index of the second polycarbonate resin. As a result, the first polycarbonate resin and the second polycarbonate resin are compatible with each other to form a sea in a sea-island structure, and the styrene-based resin forms islands in the sea-island structure. Furthermore, the refractive index difference between the polycarbonate resin region (sea) and the styrene-based resin region (islands) is reduced, which is presumably why a material with low retardation and high transparency can be provided.

[0014] <Polycarbonate Resin> The resin composition of this embodiment contains a first polycarbonate resin and a second polycarbonate resin. The refractive index of the first polycarbonate resin is lower than that of the styrene-based resin, and the refractive index of the second polycarbonate resin is higher than that of the styrene-based resin. By including polycarbonate resins with different refractive indices in this manner, the difference in refractive index from the styrene-based resin can be reduced. The polycarbonate resin is not particularly limited as long as it contains a —[O-R-OC(═O)]— unit containing a carbonate bond in the molecular main chain (where R is an organic group, preferably a hydrocarbon group, more preferably an aliphatic group, an aromatic group, or one containing both an aliphatic group and an aromatic group, and further one having a linear or branched structure). In this embodiment, the first polycarbonate resin and the second polycarbonate resin are each independently preferably an aromatic polycarbonate resin, and more preferably a bisphenol-type aromatic polycarbonate resin. In this embodiment, the bisphenol-type aromatic polycarbonate resin refers to a resin in which 90 mol % or more of all structural units are structural units (also referred to as monomer units) having a bisphenol skeleton, and it is preferable that 95 mol % or more of all structural units are structural units having a bisphenol skeleton. The same applies to bisphenol A-type aromatic polycarbonate resins, bisphenol AP-type aromatic polycarbonate resins, etc., which will be described later.

[0015] As other structural units, the structural unit represented by formula (1) described in paragraph 0008 of WO 2017 / 099226, the descriptions in paragraphs 0043 to 0052 of WO 2017 / 099226, and the description in JP-A 2011-046769 can be referred to, the contents of which are incorporated herein by reference.

[0016] The refractive index of the first polycarbonate resin is preferably 1.570 or more, more preferably 1.575 or more, even more preferably 1.580 or more, and preferably less than 1.590, more preferably 1.588 or less, and even more preferably 1.585 or less. By setting the refractive index at or above the lower limit and below the upper limit, the number of applicable polystyrene resins increases, and the desired performance tends to be easily imparted to the resulting resin composition or molded article. When the resin composition of this embodiment contains two or more first polycarbonate resins, the refractive index of the first polycarbonate resin is the sum of the values ​​obtained by multiplying the refractive index of each first polycarbonate resin by the mass fraction of each first polycarbonate in the first polycarbonate. The same applies to the second polycarbonate resin and the styrene-based resin.

[0017] The difference in refractive index between the first polycarbonate resin and the styrene-based resin is greater than 0, and is preferably 0.100 or less, more preferably 0.080 or less, even more preferably 0.040 or less, still more preferably 0.030 or less, even more preferably 0.020 or less, and still more preferably 0.010 or less.

[0018] The viscosity average molecular weight (Mv) of the first polycarbonate resin is preferably 9,000 or more, more preferably 10,000 or more, and even more preferably 15,000 or more. The upper limit of Mv is preferably 100,000 or less, more preferably 80,000 or less, even more preferably 50,000 or less, and even more preferably 30,000 or less. By setting it below the lower limit, the retardation of the resulting molded article tends to be lower. The viscosity average molecular weight (Mv) of the polycarbonate resin is calculated from the intrinsic viscosity (η) (unit: dL / g) at 20°C using methylene chloride as a solvent and an Ubbelohde viscometer, using the following Schnell viscosity formula: η = 1.23 × 10 －４ Mv ０．８３When the resin composition of the present embodiment contains two or more types of first polycarbonate resins, the total mass fraction is the sum of the values ​​obtained by multiplying the viscosity average molecular weight of each polycarbonate resin by its mass fraction.

[0019] The first polycarbonate resin has an MVR of 2.0 cm when measured under conditions of 300°C and a load of 1.20 kgf. ３ / 10 minutes or more is preferable, and 4.0 cm ３ / 10 minutes or more is more preferable, and 6.0 cm ３ / 10 minutes or more is more preferable, and 7.5 cm ３ / 10 minutes or more is more preferable, and 15 cm ３ / 10 minutes or more is more preferable, and ３ / 10 minutes or less is preferable. By making the MVR equal to or greater than the lower limit, the retardation of the resulting molded article tends to be lower. Furthermore, by making the MVR equal to or less than the upper limit, the impact resistance tends to be improved. When the resin composition of the present embodiment contains two or more first polycarbonate resins, it is preferable that the sum of the values ​​obtained by multiplying the MVR of each first polycarbonate resin by its mass fraction falls within the above range.

[0020] The first polycarbonate resin preferably contains at least one of a bisphenol A type aromatic polycarbonate resin and a bisphenol C type aromatic polycarbonate resin, and more preferably contains a bisphenol A type aromatic polycarbonate resin. The bisphenol A type aromatic polycarbonate resin is preferably a resin in which 90 mol % or more of all structural units are structural units derived from bisphenol A (i.e., 2,2-bis(4-hydroxyphenyl)propane), and more preferably 95 mol % or more of all structural units are such structural units. The bisphenol C type aromatic polycarbonate resin is preferably a resin in which 90 mol % or more of all structural units are structural units derived from bisphenol C (i.e., 2,2-bis(4-hydroxy-3-methylphenyl)propane), and more preferably 95 mol % or more of all structural units are such structural units.

[0021] On the other hand, the refractive index of the second polycarbonate resin is preferably 1.590 or more, more preferably 1.605 or more, even more preferably 1.610 or more, particularly preferably 1.640 or more, and is preferably 1.700 or less, more preferably 1.670 or less, and even more preferably 1.650 or less. By setting the refractive index to be equal to or greater than the lower limit and equal to or less than the upper limit, the number of applicable polystyrene resins increases, and it tends to be easier to impart desired performance to the resulting resin composition or molded article.

[0022] The difference in refractive index between the second polycarbonate resin and the styrene-based resin is greater than 0 and is preferably 0.100 or less, more preferably 0.080 or less, even more preferably 0.040 or less, and even more preferably 0.030 or less.

[0023] The viscosity average molecular weight (Mv) of the second polycarbonate resin is preferably 9,000 or more, more preferably 10,000 or more, and more preferably 50,000 or less, more preferably 30,000 or less, and even more preferably 25,000 or less. By setting it to the above lower limit or less, the retardation of the obtained molded article tends to be lower. The viscosity average molecular weight (Mv) of the second polycarbonate resin is measured by the same measurement method as the measurement method for the viscosity average molecular weight (Mv) of the first polycarbonate resin.

[0024] The second polycarbonate resin preferably has excellent heat resistance. Specifically, the glass transition temperature of the second polycarbonate resin is preferably 155°C or higher, more preferably 160°C or higher, and even more preferably 165°C or higher, and is preferably 200°C or lower, more preferably 195°C or lower, and even more preferably 190°C or lower. The glass transition temperature (Tg) of the second polycarbonate resin is measured by performing two cycles of temperature increase and decrease according to the following differential scanning calorimetry (DSC) measurement conditions, and measuring the glass transition temperature during the second temperature increase cycle. The measurement conditions are: starting temperature: 30°C, temperature increase rate: 10°C / min, final temperature: 250°C, and temperature decrease rate: 20°C / min. A differential scanning calorimeter (DSC, manufactured by Hitachi High-Tech Science Corporation, "DSC7020") can be used as the measurement device. When the resin composition of the present embodiment contains two or more types of second polycarbonate resins, the glass transition temperature is the sum of values ​​obtained by multiplying the glass transition temperature of each polycarbonate resin by its mass fraction.

[0025] The second polycarbonate resin preferably comprises at least one selected from the group consisting of bisphenol AP type aromatic polycarbonate resins, bisphenol BP type aromatic polycarbonate resins, and fluorene polycarbonate resins, and more preferably comprises a bisphenol AP type aromatic polycarbonate resin and / or a fluorene polycarbonate resin. The bisphenol AP type aromatic polycarbonate resin is preferably a resin in which 90 mol % or more of all structural units are derived from bisphenol AP (i.e., 1,1-bis(4-hydroxyphenyl)-1-phenylethane), and more preferably 95 mol % or more of all structural units are derived from bisphenol AP. The bisphenol BP aromatic polycarbonate resin is preferably a resin in which 90 mol % or more of all structural units are structural units derived from bisphenol BP (i.e., 1,1-bis(4-hydroxyphenyl-1,1-diphenylmethane), and more preferably 95 mol % or more of all structural units are such structural units. The fluorene polycarbonate resin is preferably a resin in which 50 mol % or more of all structural units are structural units represented by the following formula (a), more preferably 55 mol % or more, even more preferably 80 mol % or more, and even more preferably 90 mol % or more, and particularly preferably a resin in which 95 mol % or more of all structural units are such structural units. Other structural units constituting the fluorene polycarbonate resin include structural units derived from monomers having a bisphenol skeleton, such as bisphenol A, bisphenol C, and bisphenol TMC (i.e., 4,4'-(3,3,5-trimethylcyclohexylidene)bisphenol). The structural unit represented by formula (1) described in paragraph 0008 of WO 2017 / 099226, the descriptions in paragraphs 0043 to 0052 of WO 2017 / 099226, and the description in JP 2011-046769 A can also be referenced, the contents of which are incorporated herein by reference. Formula (a)

[0026] The method for producing the first polycarbonate resin and the second polycarbonate resin is not particularly limited, and any known method can be adopted.Examples thereof include interfacial polymerization, melt transesterification, pyridine method, ring-opening polymerization of cyclic carbonate compounds, and solid-phase transesterification of prepolymers.Among these, interfacial polymerization and melt transesterification are preferred, and interfacial polymerization is more preferred.

[0027] In the resin composition of this embodiment, the difference in refractive index between the first polycarbonate resin and the second polycarbonate resin is preferably 0.001 or more, more preferably 0.005 or more, even more preferably 0.010 or more, even more preferably 0.020 or more, and preferably 0.100 or less, more preferably 0.080 or less, even more preferably 0.060 or less, and even more preferably 0.040 or less. By setting the difference at or above the lower limit, the number of applicable polystyrene resins increases, and the desired performance tends to be easily imparted to the resulting resin composition or molded article. Furthermore, by setting the difference at or below the upper limit, the compatibility between the first polycarbonate resin and the second polycarbonate resin tends to be improved. A small difference in SP value (solubility parameter) between the first polycarbonate resin and the second polycarbonate resin is preferable because it improves compatibility and transparency. The difference in SP value between the first polycarbonate resin and the second polycarbonate resin is preferably 2.5 or less, more preferably 2.2 or less.

[0028] The polycarbonate resin used in the present embodiment may include recycled products, such as those obtained by material recycling in which scraps or rejected products of molded products, or recovered used polycarbonate resin molded products are crushed, washed, and reused, or those obtained by chemical recycling (chemical decomposition method).

[0029] In the resin composition of this embodiment, it is preferable to contain 50 to 97 parts by mass of the first polycarbonate resin and 3 to 50 parts by mass of the second polycarbonate resin, relative to 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin. The content of the first polycarbonate resin is preferably 55 parts by mass or more, more preferably 60 parts by mass or more, even more preferably 65 parts by mass or more, even more preferably 70 parts by mass or more, even more preferably 75 parts by mass or more, and even more preferably 80 parts by mass or more, 85 parts by mass or more, 87 parts by mass or more, 90 parts by mass or more, and preferably 95 parts by mass or less. By setting it to the lower limit or more, impact resistance tends to be improved. Furthermore, by setting it to the upper limit or less, retardation tends to be easily reduced.

[0030] In this embodiment, it is preferable that the first polycarbonate resin contains a bisphenol A type aromatic polycarbonate resin, and the second polycarbonate resin contains a bisphenol AP type aromatic polycarbonate resin and / or a fluorene polycarbonate resin.

[0031] The resin composition of this embodiment preferably contains 50% by mass or more of polycarbonate resin (total of the first polycarbonate resin and the second polycarbonate resin), more preferably 55% by mass or more. Depending on the application, etc., it may be 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, or 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. Depending on the application, etc., it may be 80% by mass or less, 78% by mass or less, 75% by mass or less. The resin composition of this embodiment may contain only one type of first polycarbonate resin and one type of second polycarbonate resin, or two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0032] <Styrene-based resin> The resin composition of this embodiment contains a styrene-based resin. By containing a styrene-based resin, it is possible to achieve low retardation. The styrene-based resin used in this embodiment preferably has a refractive index of 1.571 or more, more preferably 1.575 or more, even more preferably 1.580 or more, and even more preferably 1.585 or more, and preferably 1.699 or less, more preferably 1.670 or less, even more preferably 1.640 or less, and even more preferably 1.610 or less. By making the refractive index below the upper limit, impact resistance tends to be improved.

[0033] The styrene-based resin in this embodiment may be a homopolymer of a styrene-based monomer, a copolymer of a styrene-based monomer and a monomer copolymerizable with the styrene-based monomer, or the like. In the styrene-based resin in this embodiment, the styrene-based monomer units preferably account for 30% by mass or more of the total monomer units, more preferably 40% by mass or more, and even more preferably 50% by mass or more. A first embodiment of the styrene-based resin is a styrene-based resin (i.e., a polystyrene resin) in which more than 90% by mass of all monomer units are styrene-based monomers, preferably more than 95% by mass of all monomer units are styrene-based monomers, more preferably more than 98% by mass of all monomer units are styrene-based monomers, and may even be 100% by mass of all monomer units are styrene-based monomers.

[0034] A second embodiment of the styrene-based resin is a styrene-based resin containing 20 to 90% by mass of styrene-based monomer units, 1 to 30% by mass of maleic anhydride monomer units, and 0 to 60% by mass of other monomer units (however, the total of the styrene-based monomer units, maleic anhydride monomer units, and other monomer units does not exceed 100% by mass). In the second embodiment, the total of the styrene-based monomer units and maleic anhydride monomer units is preferably 40% by mass or more, more preferably 50% by mass or more, and may even be 100% by mass. An example of the other monomer units is N-phenylmaleimide monomer units. Furthermore, the other monomer units may be monomer units derived from the monomers listed below as monomers other than styrene-based monomers.

[0035] The styrene-based monomer refers to styrene and substituted styrene, and examples thereof include styrene, α-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, tribromostyrene, etc., with styrene and α-methylstyrene being more preferred, and styrene being particularly preferred. Furthermore, among the monomers constituting the styrene-based resin, examples of monomers other than styrene-based monomers include (meth)acrylic acid ester-based monomers, maleimide-based monomers such as maleimide, N-methylmaleimide, and N-phenylmaleimide, α,β-unsaturated carboxylic acids and anhydrides thereof such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid, and rubbers such as butadiene.

[0036] The styrene-based resin used in this embodiment may or may not contain a rubber-reinforced polystyrene resin. Preferably, the resin composition of this embodiment is substantially free of rubber-reinforced styrene-based resin. "Substantially free" means that the content of the rubber-reinforced styrene-based resin contained in the resin composition of this embodiment is less than 10% by mass of the content of the styrene-based resin, preferably less than 5% by mass, more preferably less than 3% by mass, and even more preferably less than 1% by mass. Specific examples of rubber-reinforced styrene-based resins include acrylonitrile-styrene copolymers (AS resins), high-impact polystyrene resins (HIPS), acrylonitrile-butadiene-styrene copolymers (ABS resins), acrylonitrile-acrylic rubber-styrene copolymers (AAS resins), acrylonitrile-styrene-acrylic rubber copolymers (ASA resins), acrylonitrile-ethylene propylene rubber-styrene copolymers (AES resins), and styrene-IPN type rubber copolymers.

[0037] The weight-average molecular weight of the styrene-based resin used in this embodiment is preferably 2,000 or more, more preferably 5,000 or more, even more preferably 10,000 or more, even more preferably 50,000 or more, even more preferably 100,000 or more, and is preferably 500,000 or less, more preferably 450,000 or less, even more preferably 400,000 or less, and even more preferably 350,000 or less. By making the weight-average molecular weight equal to or greater than the lower limit, impact resistance tends to be improved. On the other hand, by making the weight-average molecular weight equal to or less than the upper limit, transparency tends to be improved. The weight average molecular weight is measured by GPC (gel permeation chromatography) using a Tosoh HLC-8320GPC EcoSEC, tetrahydrofuran as a solvent, and three Shodex KF-G, KF-805L, and a KF-800D as columns at a column temperature of 40°C and a flow rate of 1.2 mL / min, and is expressed as a polystyrene-equivalent value detected with a detector (UV-8320) at a detection wavelength of 254 nm.

[0038] The styrene-based resin used in this embodiment may include recycled products. Examples of recycled styrene-based resins include those obtained by material recycling in which scraps or rejected products of molded products, or recovered used styrene-based resin molded products are crushed, washed, and reused, and those obtained by chemical recycling (chemical decomposition method).

[0039] The content of the styrene-based resin in the resin composition of this embodiment is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, relative to 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin. It is also preferably 100 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, even more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less. By making it equal to or greater than the lower limit, retardation tends to be further reduced. Furthermore, by making it equal to or less than the upper limit, impact resistance tends to be improved. The resin composition of this embodiment may contain only one type of styrene-based resin, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is within the above range.

[0040] The resin composition of this embodiment also comprises 50 to 97 parts by mass of a first polycarbonate resin and 3 to 50 parts by mass of a second polycarbonate resin, and 5 to 100 parts by mass of a styrene-based resin per 100 parts by mass of the total of 50 to 97 parts by mass of a first polycarbonate resin and 3 to 50 parts by mass of a second polycarbonate resin. The first polycarbonate resin comprises a bisphenol A type aromatic polycarbonate resin, and the second polycarbonate resin comprises a bisphenol AP type aromatic polycarbonate resin and / or a fluorene polycarbonate resin. The styrene-based resin comprises at least one of a styrene-based resin having more than 90% by mass of all monomer units as a styrene-based monomer, and a styrene-based resin containing 20 to 90% by mass of styrene-based monomer units, 1 to 30% by mass of maleic anhydride monomer units, and 0 to 60% by mass of N-phenylmaleimide monomer units. Furthermore, it is preferable that the haze of the resin composition when molded to a thickness of 3 mm is less than 20%. In addition, the details of the first polycarbonate resin, the second polycarbonate resin, and the styrene-based resin are preferably in the same ranges as those of the first polycarbonate resin, the second polycarbonate resin, and the styrene-based resin described in the section on the resin composition above.

[0041] <Stabilizer> The resin composition of this embodiment may contain a stabilizer. Examples of the stabilizer include a heat stabilizer and an antioxidant. Examples of the stabilizer include phenol-based, amine-based, phosphorus-based, and thioether-based stabilizers. Among these, in this embodiment, a phosphorus-based heat stabilizer and / or a phenol-based antioxidant is preferred.

[0042] Any known phosphorus-based heat stabilizer can be used. Specific examples include phosphorus oxoacids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; metal acid pyrophosphates such as sodium acid pyrophosphate, potassium acid pyrophosphate, and calcium acid pyrophosphate; phosphates of Group 1 or Group 2B metals such as potassium phosphate, sodium phosphate, cesium phosphate, and zinc phosphate; organic phosphate compounds, organic phosphite compounds, and organic phosphonite compounds, with organic phosphite compounds being particularly preferred.

[0043] Examples of the organic phosphite compound include triphenyl phosphite, tris(mononylphenyl)phosphite, tris(mononyl / dinonyl phenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, monooctyldiphenyl phosphite, dioctylmonophenyl phosphite, monodecyldiphenyl phosphite, didecylmonophenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, and 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite. Specific examples of such organic phosphite compounds include "ADK STAB (registered trademark; the same applies hereinafter) 1178," "ADK STAB 2112," and "ADK STAB HP-10" manufactured by ADEKA Corporation; "JP-351," "JP-360," and "JP-3CP" manufactured by Johoku Chemical Industry Co., Ltd.; and "IRGAFOS (registered trademark; the same applies hereinafter) 168" manufactured by BASF.

[0044] As the phenol-based antioxidant, a hindered phenol-based antioxidant is preferably used. Specific examples of the hindered phenol-based antioxidant include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphate, 4,6-bis(octyl methylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, and the like.

[0045] Among these, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate are preferred. Specific examples of such hindered phenol-based antioxidants include "Irganox (registered trademark; the same applies hereinafter) 1010" and "Irganox 1076" manufactured by BASF, and "ADK STAB AO-50" and "ADK STAB AO-60" manufactured by ADEKA Corporation.

[0046] The content of the stabilizer in the resin composition of this embodiment is usually 0.001 parts by mass or more, preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and usually 1 part by mass or less, preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, per 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin. By setting the content of the stabilizer within the above range, the effect of adding the stabilizer can be more effectively exhibited. The resin composition of this embodiment may contain only one type of stabilizer, or may contain two or more types. When two or more types are contained, it is preferable that the total amount be in the above range.

[0047] <Release Agent> The resin composition of the present embodiment may contain a release agent. Examples of the release agent include aliphatic carboxylic acids, salts of aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, polysiloxane-based silicone oils, ketone waxes, and light amides. Of these, aliphatic carboxylic acids, salts of aliphatic carboxylic acids, and esters of aliphatic carboxylic acids and alcohols are preferred, and esters of aliphatic carboxylic acids and alcohols are more preferred.

[0048] Examples of esters of aliphatic carboxylic acids and alcohols include saturated or unsaturated monovalent or divalent aliphatic carboxylic acid esters, fatty acid esters such as glycerin fatty acid esters and sorbitan fatty acid esters, and partially saponified products thereof. Among these, mono- or di-fatty acid esters composed of a fatty acid having preferably 11 to 28 carbon atoms, more preferably 17 to 21 carbon atoms, and an alcohol are preferred.

[0049] Examples of fatty acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetraacontanoic acid, montanic acid, adipic acid, and azelaic acid. The fatty acids may also be alicyclic. Examples of alcohols include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, monohydric or polyhydric saturated alcohols having 30 or less carbon atoms are preferred, and aliphatic saturated monohydric or polyhydric alcohols having 30 or less carbon atoms are more preferred. Here, the term "aliphatic" also includes alicyclic compounds. Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, and dipentaerythritol. The above ester compound may contain an aliphatic carboxylic acid and / or an alcohol as an impurity, and may be a mixture of a plurality of compounds.

[0050] Specific examples of fatty acid ester compounds include glycerin monostearate, glycerin monobehenate, glycerin dibehenate, glycerin-12-hydroxymonostearate, sorbitan monobehenate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tetrastearate, stearyl stearate, ethylene glycol montanic acid ester, etc. Details of the release agent can be found in addition to the above, and in paragraphs

[0055] to

[0060] of JP2018-095706A and paragraphs

[0106] to

[0115] of JP2015-117298A, the contents of which are incorporated herein by reference.

[0051] When the resin composition of this embodiment contains a release agent, the content thereof is preferably 0.001 to 3 parts by mass, and more preferably 0.005 to 0.8 parts by mass, relative to 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin. The resin composition of this embodiment may contain only one type of release agent, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0052] <Other Components> The resin composition of this embodiment may further contain other components other than those described above. Examples of other components include reinforcing materials, colorants, flame retardants, flame retardant aids, ultraviolet absorbers, fluorescent brighteners, impact modifiers, epoxy compounds, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiviral agents, and the like. For details of these components, please refer to the descriptions in paragraphs 0107 to 0115 of JP 2014-136710 A, the descriptions in paragraphs 0106 to 0128 of JP 2015-117298 A, the descriptions in paragraphs 0055 to 0061 of JP 2018-095706 A, and the descriptions in paragraphs 0047 to 0103 of WO 2021 / 241471 A, the contents of which are incorporated herein by reference. When the other components are contained, the content thereof is, for example, 0.001% by mass or more, and, for example, 5.0% by mass or less, preferably 3.0% by mass or less, and more preferably 1.0% by mass or less, based on the mass of the resin composition. In the resin composition of this embodiment, the first polycarbonate resin, the second polycarbonate resin, and the styrene-based resin preferably account for 95% by mass or more of the resin composition, more preferably 97% by mass or more, and even more preferably 98% by mass or more. In addition, in the resin composition of this embodiment, the first polycarbonate resin, the second polycarbonate resin, the styrene-based resin, the release agent, and the stabilizer preferably account for 96% by mass or more of the resin composition, more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0053] <Physical Properties of Resin Composition> The resin composition of this embodiment preferably has excellent transparency. Specifically, when the resin composition of this embodiment is molded to a thickness of 3 mm, the total light transmittance of a test piece is preferably 85% or more, more preferably 87% or more, and may be 100% or less, or even 99% or less. Furthermore, when the resin composition of this embodiment is molded to a thickness of 3 mm, the haze is preferably less than 20%, more preferably 19% or less, more preferably 18% or less, even more preferably 10% or more, even more preferably 7% or less, and even more preferably 5% or less. The lower limit is preferably 0% or more, and practically 0.1% or more. Such excellent transparency is achieved by making the refractive index difference between the polycarbonate resin and the styrene-based resin closer. For example, when the refractive index of a styrene-based resin is 1.589 and the refractive index of a bisphenol A-type aromatic polycarbonate resin is 1.582, the refractive indices of the polycarbonate resin and the styrene-based resin are far apart, but by making a bisphenol AP-type aromatic polycarbonate resin and / or a fluorene polycarbonate resin, which have higher refractive indices, compatible with each other and bringing the refractive index of the polycarbonate resin phase, which is a combination of the first and second resins, closer to that of the styrene-based resin, the transparency of the entire resin composition can be increased.

[0054] Furthermore, the YI value (Yellow Index) of a test piece obtained by molding the resin composition of this embodiment to a thickness of 3 mm is preferably 20 or less, more preferably 19 or less, even more preferably 15 or less, still more preferably 10 or less, even more preferably 7 or less, and still more preferably 5 or less, and is preferably 0 or more, and even if it is 1 or more, the required performance is satisfied.

[0055] The resin composition of this embodiment preferably has low retardation. Specifically, when the resin composition is molded into a test piece having a thickness of 2 mm, the average retardation value is preferably less than 700 nm, more preferably 650 nm or less, even more preferably 600 nm or less, even more preferably 500 nm or less, even more preferably 450 nm or less, even more preferably 400 nm or less, and may even be 350 nm or less, 330 nm or less, or 300 nm or less. The lower limit of the average retardation value is preferably 0 nm or more, and the required performance is satisfied even if it is 50 nm or more, or even 100 nm or more.

[0056] The total light transmittance, haze, YI value, and average retardation value are measured according to the description in the examples described below.

[0057] <Method for Producing Resin Composition> The resin composition of this embodiment can be produced by a conventional method for producing a resin composition containing a thermoplastic resin. For example, it can be obtained by melt-kneading a first polycarbonate resin, a second polycarbonate resin, and a styrene-based resin. One form formed from such a resin composition is pellets. The components may be pre-mixed and fed to the extruder all at once, or the components may be pre-mixed or only a portion of the components may be pre-mixed and fed to the extruder using a feeder. The extruder may be a single-screw extruder or a twin-screw extruder. Furthermore, when a reinforcing material such as glass fiber is blended, it is preferable to feed it from a side feeder midway through the cylinder of the extruder. The heating temperature during melt-kneading can usually be selected appropriately from the range of 150 to 350°C.

[0058] <Method for Producing Molded Articles> Molded articles are formed from the resin composition or pellets of this embodiment. The shape of the molded article is not particularly limited and can be appropriately selected depending on the application and purpose of the molded article. Examples include film-like, rod-like, cylindrical, annular, circular, elliptical, polygonal, irregularly shaped, hollow, frame-like, box-like, panel-like, and button-like shapes. The method for producing the molded article in this embodiment is not particularly limited, and any molding method commonly used for resin compositions containing thermoplastic resins can be used. Examples include injection molding, ultra-high speed injection molding, injection compression molding, two-color molding, gas-assisted hollow molding, molding using an insulated mold, molding using a rapidly heated mold, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding), extrusion molding, sheet molding, thermoforming, rotational molding, laminate molding, press molding, and blow molding. Of these, injection molding and extrusion molding are preferred. When the film is produced by extrusion molding, the film formability can be improved by increasing the molecular weight of the polycarbonate resin.

[0059] <Applications> The molded article of this embodiment can be widely used for molded articles containing thermoplastic resins, particularly for applications requiring transparency and low retardation. Specifically, optical molded articles, more specifically, various lenses, for example, lenses for various cameras, telescopes, microscopes, projectors, optical measuring devices, etc., various optical discs, home televisions, PC displays, car navigation systems, car audio, etc. In-vehicle display devices, such as smartphones, head-mounted displays, barcode readers, scanners, etc., panel members and films of display devices used in scanners, etc. are preferred. In particular, it can be suitably used as a panel member for display devices used in various mobile terminals such as smartphones, tablet PCs, car navigation systems, car audio, portable game consoles, digital cameras, etc., particularly as a front surface member of the display device, and more suitably used as a lens for various cameras, telescopes, microscopes, projectors, optical measuring devices, etc.

[0060] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0061] 1. Raw materials The raw materials shown in Table 1 were used.

[0062] <Measurement of Refractive Index> The refractive index of polycarbonate resin and styrene-based resin was measured in accordance with JIS K7142 at a temperature of 23±1° C., a humidity of 50±5% RH, and a sodium D line at 589 nm.

[0063] 2. Examples 1 to 29 and Comparative Examples 1 to 7 <Compounds> The components listed in Table 1 were blended in the proportions (all parts by mass) listed in Tables 2 to 7 and mixed uniformly in a tumbler mixer to obtain a mixture. This mixture was fed into a twin-screw extruder ("TEX26SX" manufactured by Shibaura Machine Co., Ltd.), kneaded at a screw rotation speed of 150 rpm, a discharge rate of 20 kg / hour, and a barrel temperature of 280°C, and extruded in the form of a strand from the tip of the extrusion nozzle. The extrudate was quenched in a water bath and cut and pelletized using a pelletizer to obtain pellets of the resin composition.

[0064] <Optical Properties> Each resin composition obtained above was injection molded using an SE100DU injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. under conditions of a resin temperature of 280°C and a mold temperature of 80°C to form two-stage plates (2 mm thick and 3 mm thick). The total light transmittance (unit: %) and haze (unit: %) were measured for a 3 mm thick portion of the obtained two-stage plate. The total light transmittance and haze were measured using a haze meter with a D65 light source in accordance with ASTM-D1003. The haze meter used was an "NDH4000" (trade name) manufactured by Nippon Denshoku Industries Co., Ltd. Furthermore, the YI value (Yellow Index) was measured for a 3 mm thick portion of the two-stage plate using a C light source, a 2° field of view, and a transmission method. An SE6000 spectrophotometer manufactured by Nippon Denshoku Industries Co., Ltd. was used.

[0065] <Retardation> Each of the resin compositions obtained above was injection molded using an SE100DU injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. under conditions of a resin temperature of 280°C and a mold temperature of 80°C. ２ A test piece having an area of ​​100 mm obtained above was manufactured by measuring three wavelengths (wavelengths of 523 nm, 543 nm, and 575 nm) using a wide-range two-dimensional birefringence evaluation device ("WPA-200-L" manufactured by Photonic Lattice). ２ The phase difference in the entire 2 mm thick test piece was analyzed by area analysis, and the average value (average retardation, unit: nm) was calculated.

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072] In the table above, the proportions (parts by mass) of C1 to C8 indicate the amount (parts by mass) of the styrene-based resin added relative to 100 parts by mass of the first polycarbonate resin (A1 to A3) and the second polycarbonate resin (B1 to B3). Furthermore, the proportions (parts by mass) of B1 to B3 indicate the amount (parts by mass) of the second polycarbonate resin added relative to 100 parts by mass of the first polycarbonate resin and the second polycarbonate resin. As is clear from the above results, the resin compositions of the present invention were capable of providing molded articles with low retardation and excellent transparency (Examples 1 to 29). Furthermore, the YI values ​​were also low (Examples 1 to 29). In contrast, molded articles obtained from the resin compositions of the comparative examples had high retardation or poor transparency (Comparative Examples 1 to 7).

Claims

1. A resin composition comprising a first polycarbonate resin, a second polycarbonate resin, and a styrene-based resin, wherein the refractive indexes of the first polycarbonate resin, the second polycarbonate resin, and the styrene-based resin satisfy the following relationship: refractive index of the first polycarbonate resin < refractive index of the styrene-based resin < refractive index of the second polycarbonate resin, and the resin composition has a haze of less than 20% when molded to a thickness of 3 mm.

2. The resin composition according to claim 1, which contains 5 to 100 parts by mass of a styrene-based resin per 100 parts by mass of the first polycarbonate resin and the second polycarbonate resin combined.

3. The resin composition according to claim 1 or 2, wherein the refractive index of the first polycarbonate resin is 1.570 or more and less than 1.

590.

4. The resin composition according to claim 1 or 2, wherein the first polycarbonate resin comprises a bisphenol A type aromatic polycarbonate resin.

5. The resin composition according to claim 1 or 2, wherein the refractive index of the second polycarbonate resin is 1.590 to 1.

700.

6. The resin composition according to claim 1 or 2, wherein the second polycarbonate resin comprises a bisphenol AP type aromatic polycarbonate resin.

7. The resin composition according to claim 1 or 2, wherein the second polycarbonate resin comprises a fluorene polycarbonate resin.

8. The resin composition according to claim 1 or 2, wherein the refractive index of the styrene-based resin is 1.571 to 1.

699.

9. The resin composition according to claim 1 or 2, comprising at least one of a styrene-based resin in which more than 90 mass % of all monomer units are styrene-based monomers, and a styrene-based resin containing 20 to 90 mass % of styrene-based monomer units, 1 to 30 mass % of maleic anhydride monomer units, and 0 to 60 mass % of N-phenylmaleimide monomer units.

10. A resin composition according to claim 1 or 2, wherein the styrene-based resin is a styrene-based resin in which more than 90 mass% of all monomer units are styrene-based monomers.

11. The resin composition according to claim 1 or 2, comprising 50 to 97 parts by mass of the first polycarbonate resin and 3 to 50 parts by mass of the second polycarbonate resin per 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin.

12. The resin composition according to claim 1, wherein the content of the styrene-based resin is 90 parts by mass or less per 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin, and the refractive index of the second polycarbonate resin is 1.590 to 1.

700.

13. The resin composition according to claim 1, wherein the content of the styrene-based resin is 90 parts by mass or less per 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin, and the styrene-based resin is a styrene-based resin in which more than 90 mass% of all monomer units are styrene-based monomers.

14. The resin composition according to claim 1, comprising 5 to 100 parts by mass of a styrene-based resin per 100 parts by mass of the total of the first polycarbonate resin and the second polycarbonate resin, the first polycarbonate resin having a refractive index of 1.570 or more and less than 1.590, the first polycarbonate resin comprising a bisphenol A type aromatic polycarbonate resin, the second polycarbonate resin having a refractive index of 1.590 to 1.700, the second polycarbonate resin comprising a bisphenol AP type aromatic polycarbonate resin and / or a fluorene polycarbonate resin, the styrene-based resin having a refractive index of 1.571 to 1.699, and the styrene-based resin being a styrene-based resin in which styrene-based monomer units account for 90% by mass of the total monomer units.

15. A resin composition comprising 5 to 100 parts by mass of a styrene-based resin per 100 parts by mass of a total of 50 to 97 parts by mass of a first polycarbonate resin and 3 to 50 parts by mass of a second polycarbonate resin, the first polycarbonate resin comprising a bisphenol A type aromatic polycarbonate resin, the second polycarbonate resin comprising a bisphenol AP type aromatic polycarbonate resin and / or a fluorene polycarbonate resin, the styrene-based resin comprising at least one of a styrene-based resin having more than 90% by mass of all monomer units being a styrene-based monomer and a styrene-based resin comprising 20 to 90% by mass of a styrene-based monomer unit, 1 to 30% by mass of a maleic anhydride monomer unit, and 0 to 60% by mass of an N-phenylmaleimide monomer unit, the resin composition having a haze of less than 20% when molded to a thickness of 3 mm.

16. Pellets of the resin composition according to claim 1, 2, 12, 13, 14 or 15.

17. A molded article formed from the resin composition according to claim 1, 2, 12, 13, 14 or 15.

18. A molded article formed from the pellets of claim 16.

19. A lens formed from the resin composition according to claim 1, 2, 12, 13, 14 or 15.

20. A lens molded from the pellets of claim 16.

Images