Resin composition and molded article

Abstract

A resin composition which contains 0.001-0.5 parts by mass of (B) tris (2, 4-di-tert-butylphenyl) phosphate ester per 100 parts by mass of (A) polycarbonate resin, and wherein (A) polycarbonate resin contains a structural unit represented by formula (1), in which the mass of the structural unit represented by formula (1) relative to the mass of (B) tris (2, 4-di-tert-butylphenyl) phosphate ester per 100 parts by mass of (A) polycarbonate resin, and the mass of (B) tris (2, 4-di-tert-butylphenyl) phosphate ester per 100 parts by mass of (A) polycarbonate resin per 100 parts by mass of (A) polycarbonate resin per 100 parts by mass of (A) polycarbonate resin. The mass ratio (B) / (A-2) of the 2, 4-di-tert-butylphenyl) phosphate ester satisfies 0.00003 < = (B) / (A-2) < = 0.0050. In formula (1), R1 represents a methyl group. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a resin composition and a molded product, and particularly to a resin composition containing a polycarbonate resin as a main component. Background Art

[0002] Polycarbonate resins are excellent in mechanical strength, electrical properties, transparency, etc., and are widely used as engineering plastics in various fields such as the electric and electronic equipment field and the automobile field.

[0003] For example, Patent Document 1 discloses a static-resistant polycarbonate composition comprising polycarbonate, at least one release agent, and at least one antistatic agent. The disclosed composition may contain a heat stabilizer, and a static-resistant optical disc may be molded from the polycarbonate composition.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 11-279396 Summary of the invention

[0007] Problems to be solved by the invention

[0008] As mentioned above, polycarbonate resins are used for various purposes. Here, as polycarbonate resins, polycarbonate resins with bisphenol A as the main raw material (bisphenol A type polycarbonate resins) are generally used. On the other hand, in order to improve the surface hardness, polycarbonate resins with bisphenol C as the main raw material (bisphenol C type polycarbonate resins) are studied.

[0009] Here, if bisphenol C type polycarbonate resin is mixed, the surface hardness of the obtained molded product tends to increase, but compared with bisphenol A type polycarbonate resin, it is known that it is easy to yellow. In particular, it is known that the wet heat discoloration stability is poor through the research conducted by the inventor. Therefore, in the molded product mixed with bisphenol C type polycarbonate resin, it is also required that the difference in the degree of yellowing between the molded product subjected to wet heat treatment and the molded product not subjected to wet heat treatment is small.

[0010] The present invention aims to solve the above problems and provides a resin composition and a molded article. The resin composition is a resin composition using a polycarbonate resin containing a structural unit represented by the formula (1) described later, such as a bisphenol C-type polycarbonate resin, and when the resin composition is made into a molded article, the difference in the degree of yellowing is small when the molded article is subjected to a wet heat treatment and when the molded article is not subjected to a wet heat treatment.

[0011] Means for solving problems

[0012] The present inventors have conducted studies based on the above problems and have found that the above problems can be solved by blending tris(2,4-di-tert-butylphenyl)phosphate into a predetermined polycarbonate resin such as a bisphenol C polycarbonate resin.

[0013] Specifically, the above-mentioned problems were solved by the following means.

[0014] <1> A resin composition comprising 0.001 to 0.5 parts by mass of (B) tris(2,4-di-tert-butylphenyl) phosphate relative to 100 parts by mass of (A) polycarbonate resin, wherein the (A) polycarbonate resin comprises a structural unit represented by formula (1), wherein in the resin composition, a ratio (B) / (A-2) of the mass of the structural unit represented by formula (1) to the mass of the (B) tris(2,4-di-tert-butylphenyl) phosphate satisfies 0.00003≤(B) / (A-2)≤0.0050.

[0015] Formula (1)

[0016] [Chemistry 1]

[0017]

[0018] (In formula (1), R 1 Represents methyl, R 2 represents a hydrogen atom or a methyl group, X 2 represents any of the following,

[0019] [Chemistry 2]

[0020]

[0021] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group that is bonded to C to form an alicyclic hydrocarbon group having 6 to 12 carbon atoms and may have a substituent.

[0022] <2> like <1> The resin composition is characterized in that the polycarbonate resin (A) contains the structural unit represented by the formula (1) in a ratio of 10 to 95 mol % in all structural units.

[0023] <3> like <1> The resin composition is characterized in that the polycarbonate resin (A) contains the structural unit represented by the formula (1) in a ratio of 10 to 80 mol % in all structural units.

[0024] <4> like <1> ~ <3> The resin composition described above, wherein the polycarbonate resin (A) further comprises a structural unit represented by formula (2).

[0025] Formula (2)

[0026] [Chemistry 3]

[0027]

[0028] (In formula (2), X 1 represents any of the following,

[0029] [Chemistry 4]

[0030]

[0031] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group that is bonded to C to form an alicyclic hydrocarbon group having 6 to 12 carbon atoms and may have a substituent.

[0032] <5> like <4> The resin composition described above, wherein the polycarbonate resin (A) comprising the structural unit represented by the formula (2) comprises a recycled product.

[0033] <6> like <5> The resin composition described above, wherein the ratio of the recycled product in the polycarbonate resin (A) is 5 to 80% by mass.

[0034] <7> like <1> ~ <6> The resin composition described in any one of the preceding claims, wherein the polycarbonate resin (A) further comprises a structural unit represented by formula (2), and the polycarbonate resin comprising the structural unit represented by formula (2) comprises a recycled product.

[0035] Formula (2)

[0036] [Chemistry 5]

[0037]

[0038] (In formula (2), X 1 represents any of the following,

[0039] [Chemistry 6]

[0040]

[0041] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group that is bonded to C to form an alicyclic hydrocarbon group having 6 to 12 carbon atoms and may have a substituent.

[0042] <8> A pellet of a resin composition, which is <1> ~ <7> Pellets of the resin composition described above.

[0043] <9> A molded product, comprising <1> ~ <7> The resin composition described in any one of the above is formed.

[0044] <10> A molded product, comprising <8> The pellets are formed.

[0045] Effects of the Invention

[0046] According to the present invention, a resin composition and a molded article can be provided. The resin composition is a resin composition using a polycarbonate resin containing a structural unit represented by formula (1), and when the resin composition is made into a molded article, the difference in the degree of yellowing is small when it is subjected to a wet heat treatment and when it is not subjected to a wet heat treatment. DETAILED DESCRIPTION

[0047] A specific embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail below. It should be noted that the following this embodiment is an example for explaining the present invention, and the present invention is not limited to this embodiment.

[0048] In addition, in this specification, "to" is used to mean that the numerical values ​​described before and after it are included as a lower limit and an upper limit.

[0049] In this specification, various physical property values ​​and characteristic values ​​are values ​​at 23° C. unless otherwise specified.

[0050] When the measurement methods and the like described in the standards shown in this specification differ by year, unless otherwise specified, they are based on the standards as of January 1, 2022.

[0051] The resin composition of the present embodiment is a resin composition comprising 0.001 to 0.5 parts by mass of (B) tris(2,4-di-tert-butylphenyl) phosphate relative to 100 parts by mass of (A) polycarbonate resin, and the above-mentioned (A) polycarbonate resin comprises a structural unit represented by formula (1), characterized in that in the above-mentioned resin composition, the ratio (B) / (A-2) of the mass of the structural unit represented by the above-mentioned formula (1) to the mass of the above-mentioned tris(2,4-di-tert-butylphenyl) phosphate satisfies 0.00003≤(B) / (A-2)≤0.0050.

[0052] Formula (1)

[0053] [Chemistry 7]

[0054]

[0055] (In formula (1), R 1 Represents methyl, R 2 represents a hydrogen atom or a methyl group, X 2 represents any of the following,

[0056] [Chemistry 8]

[0057]

[0058] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group that is bonded to C to form an alicyclic hydrocarbon group having 6 to 12 carbon atoms and may have a substituent.

[0059] By adopting such a configuration, a resin composition can be provided in which the difference in the degree of yellowing between a molded product subjected to a wet heat treatment (hereinafter sometimes referred to as a "wet heat molded product") and a molded product not subjected to a wet heat treatment (hereinafter sometimes referred to as an "initial molded product") is small. In addition, by mixing a polycarbonate resin containing a structural unit represented by formula (1), a molded product with high surface hardness can be obtained.

[0060] Polycarbonate resins containing structural units represented by formula (1), such as bisphenol C polycarbonate resins, tend to easily obtain molded products with high surface hardness. On the other hand, compared with polycarbonate resins containing structural units represented by formula (2), such as bisphenol A polycarbonate resins, polycarbonate resins containing structural units represented by formula (1) tend to be easily discolored. One of the reasons for this is speculated to be that in the structural unit represented by formula (1), the benzene ring part derived from the bisphenol structure is substituted with a methyl group, and the methyl group may easily form a free radical. In this embodiment, by using tris(2,4-di-tert-butylphenyl) phosphate, the P=O part of tris(2,4-di-tert-butylphenyl) phosphate captures free radicals, and if there are more tert-butyl groups, the captured free radicals are not easy to escape, so it is speculated that yellowing can be effectively suppressed, especially yellowing of molded products under wet heat treatment. In particular, it was found that this can be achieved by setting the ratio (B) / (A-2) of the mass of the structural unit represented by the above formula (1) to the mass of (B) tris(2,4-di-tert-butylphenyl)phosphate to satisfy 0.00003≤(B) / (A-2)≤0.0050.

[0061] The details of the present invention are described below.

[0062] <(A) Polycarbonate resin>

[0063] The resin composition of the present embodiment includes the structural unit represented by the formula (1) and may include the structural unit represented by the formula (2).

[0064] Formula (1)

[0065] [Chemistry 9]

[0066]

[0067] (In formula (1), R 1 Represents methyl, R 2 represents a hydrogen atom or a methyl group, X 2 represents any of the following,

[0068] [Chemistry 10]

[0069]

[0070] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group that is bonded to C to form an alicyclic hydrocarbon group having 6 to 12 carbon atoms and may have a substituent.

[0071] Formula (2)

[0072] [Chemistry 11]

[0073]

[0074] (In formula (2), X 1 represents any of the following,

[0075] [Chemistry 12]

[0076]

[0077] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group that is bonded to C to form an alicyclic hydrocarbon group having 6 to 12 carbon atoms and may have a substituent.

[0078] The polycarbonate resin used in this embodiment may be a recycled product. In particular, in this embodiment, it is preferred that part or all of the polycarbonate resin containing the structural unit represented by formula (2) is a recycled product. It should be noted that the polycarbonate resin containing the structural unit represented by formula (1) is preferably a virgin product.

[0079] The polycarbonate resin containing the structural unit represented by formula (1) is inherently susceptible to yellowing. However, in the present embodiment, even when the polycarbonate resin containing the structural unit represented by formula (1) is blended with a recycled polycarbonate resin composed of a structural unit other than the structural unit represented by formula (1), yellowing can be effectively suppressed.

[0080] Recycled products are polycarbonate resins derived from molded products formed from polycarbonate resins. They are products that have been processed by some kind of molding on virgin polycarbonate resins, and are intended to include polycarbonate resin molded products, defective polycarbonate resin molded products, and scraps from the production of polycarbonate resin molded products. Processed molded products include injection molded products, extrusion molded products, and molded products molded by other manufacturing methods.

[0081] Examples of recycled polycarbonate resins include those obtained by material recycling (recovered used polycarbonate resin molded products are crushed, washed with alkali, and reused in fibers, etc.), those obtained by chemical recycling (chemical decomposition method), and those obtained by mechanical recycling.

[0082] Chemical regeneration is a method of chemically decomposing the recycled used polycarbonate resin molded products to restore them to the raw material level and synthesize polycarbonate resin again. On the other hand, mechanical regeneration is a method that can remove dirt from polycarbonate resin molded products more reliably than material regeneration by more strictly performing the alkali cleaning in the above-mentioned material regeneration or vacuum drying at high temperature.

[0083] For example, foreign matter is removed from a used polycarbonate resin molded article, the article is pulverized and cleaned, and then pelletized using an extruder to obtain a recycled polycarbonate resin.

[0084] Examples of used polycarbonate resin molded products include trays, sheets (including films), instrument covers, headlight lenses, and water bottles.

[0085] Virgin goods refer to goods other than recycled goods.

[0086] In the case where the resin composition of the present embodiment contains a recycled polycarbonate resin, the proportion of the recycled product in 100% by mass of the (A) polycarbonate resin is preferably 5% by mass or more, more preferably 11% by mass or more, further preferably 20% by mass or more, still more preferably 30% by mass or more, and still more preferably 35% by mass or more, and is preferably 80% by mass or less, more preferably 75% by mass or less, further preferably 70% by mass or less, and still more preferably 65% ​​by mass or less.

[0087] The polycarbonate resin used in the present embodiment, in particular, the polycarbonate resin containing the structural unit represented by formula (2) may contain (B) tris(2,4-di-tert-butylphenyl) phosphate in whole or in part. In particular, tris(2,4-di-tert-butylphenyl) phosphate is sometimes contained in recycled polycarbonate resins, and in the present embodiment, such recycled products can be effectively used.

[0088] When the (A) polycarbonate resin used in the present embodiment, particularly the polycarbonate resin containing the structural unit represented by the formula (2), contains (B) tris(2,4-di-tert-butylphenyl)phosphate, the content thereof is preferably 10 mass ppm or more, more preferably 50 mass ppm or more, further preferably 100 mass ppm or more, further preferably 150 mass ppm or more, and further preferably 200 mass ppm or more, and is preferably 1000 mass ppm or less, more preferably 800 mass ppm or less, and further preferably 500 mass ppm or less, relative to 100 parts by mass of the total amount of the polycarbonate resin containing (B) tris(2,4-di-tert-butylphenyl)phosphate.

[0089] <<Structural unit represented by formula (1)>>

[0090] The (A) polycarbonate resin used in the present embodiment contains a structural unit represented by formula (1).

[0091] Formula (1)

[0092] [Chemistry 13]

[0093]

[0094] (In formula (1), R 1 Represents methyl, R 2 represents a hydrogen atom or a methyl group, X 2 represents any of the following,

[0095] [Chemistry 14]

[0096]

[0097] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group that is bonded to C to form an alicyclic hydrocarbon group having 6 to 12 carbon atoms and may have a substituent.

[0098] The two R in formula (1) 2 They may be the same or different, but are preferably the same. 2 Preferred is a hydrogen atom.

[0099] In formula (1), X 2 for

[0100] [Chemistry 15]

[0101]

[0102] In the case of 3 and R 4 At least one of them is a methyl group, and more preferably both of them are methyl groups.

[0103] In addition, X 2 for

[0104] [Chemistry 16]

[0105]

[0106] In the case of Z, carbon C (the carbon C is bonded to the two phenyl groups in the above formula (1)) is bonded to form a divalent alicyclic hydrocarbon group having 6 to 12 carbon atoms. Examples of the divalent alicyclic hydrocarbon group include cyclohexylidene, cycloheptylidene, cyclododecylidene, adamantylidene, cyclododecylidene and other cycloalkylidene groups. As the substituted group, groups having methyl substituents and ethyl substituents thereof are included. Among these, cyclohexylidene, methyl substituted cyclohexylidene (preferably 3,3,5-trimethyl substituted cyclohexylidene) and cyclododecylidene are preferred.

[0107] In formula (1), X 2 The following structure is preferred.

[0108] [Chemistry 17]

[0109]

[0110] In this embodiment, it is particularly preferred to use the compound containing R in formula (1) 2 is a hydrogen atom, X 2 for

[0111] [Chemistry 18]

[0112] R 3 and R 4 A polycarbonate resin having a methyl structural unit.

[0113] In the present embodiment, the structural unit represented by the formula (1) in the (A) polycarbonate resin may contain only one kind or two or more kinds.

[0114] <<Structural unit represented by formula (2)>>

[0115] The (A) polycarbonate resin used in the present embodiment preferably contains a structural unit represented by formula (2).

[0116] Formula (2)

[0117] [Chemistry 19]

[0118]

[0119] (In formula (2), X 1 represents any of the following,

[0120] [Chemistry 20]

[0121]

[0122] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group that is bonded to C to form an alicyclic hydrocarbon group having 6 to 12 carbon atoms and may have a substituent.

[0123] As the alicyclic hydrocarbon formed by bonding Z to C, cycloalkylidene groups such as cyclohexylidene, cycloheptylidene, cyclododecylidene, adamantylidene, and cyclododecylidene can be cited. As the alicyclic hydrocarbon having a substituent formed by bonding Z to C, methyl substituted bodies and ethyl substituted bodies of the above alicyclic hydrocarbon groups can be cited. Among these, cyclohexylidene, methyl substituted bodies of cyclohexylidene (preferably 3,3,5-trimethyl substituted bodies), and cyclododecylidene are preferred.

[0124] In formula (2), X 1 for

[0125] [Chemistry 21]

[0126]

[0127] In the case of R 3 and R 4 Preferably at least one of the groups is a methyl group, and more preferably both of the groups are methyl groups.

[0128] In addition, X 1 for

[0129] [Chemistry 22]

[0130]

[0131] In the case of, Z is bonded to carbon C (the carbon C is bonded to the two phenyl groups in the above formula (2)) to form a divalent alicyclic hydrocarbon group having 6 to 12 carbon atoms, and examples of the divalent alicyclic hydrocarbon group include cyclohexylidene, cycloheptylidene, cyclododecylidene, adamantylidene, cyclododecylidene and other cycloalkylidene groups. As the substituted group, there can be mentioned groups having methyl substituents, ethyl substituents, etc. Among these, cyclohexylidene, methyl substituted cyclohexylidene (preferably 3,3,5-trimethyl substituted), and cyclododecylidene are preferred.

[0132] In formula (2), X 1 The following structure is preferred.

[0133] [Chemistry 23]

[0134]

[0135] A preferred specific example of the structural unit represented by the above formula (2) is a structural unit composed of 2,2-bis(4-hydroxyphenyl)propane, that is, bisphenol A (carbonate structural unit).

[0136] In the present embodiment, the polycarbonate resin (A) may not contain the structural unit represented by the formula (2), and may contain only one type of the structural unit, or may contain two or more types of the structural unit.

[0137] <<Other structural units>>

[0138] In the present embodiment, the polycarbonate resin (A) may contain other structural units in addition to the structural unit represented by the formula (1) and the structural unit represented by the formula (2). As other structural units, structural units derived from dihydroxy compounds shown below can be exemplified.

[0139] bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-(1-methylethyl)phenyl)propane, 2,2-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3-(1-methylpropyl)phenyl)propane, 2,2-bis(4-hydroxy-3-cyclohexylphenyl)propane, 2,2-bis(4-hydroxy 1,1-bis(4-hydroxyphenyl) cyclohexane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl) phenylmethane, 1,1-bis(4-hydroxy-3-methylphenyl) cyclohexane, 1,1-bis(4-hydroxy-3,5-dimethylphenyl) cyclohexane, 1,1-bis(4-hydroxy-3-(1-methylethyl) phenyl) cyclohexane, 1,1-bis(4-hydroxy-3-tert-butylphenyl) cyclohexane, 1,1-bis(4-hydroxy-3-(1-methylpropyl) phenyl) cyclohexane, 1,1-bis(4-hydroxy -3-cyclohexylphenyl)cyclohexane, 1,1-bis(4-hydroxy-3-phenylphenyl)cyclohexane, 1,1-bis(4-hydroxy-3-methylphenyl)-1-phenylethane, 1,1-bis(4-hydroxy-3,5-dimethylphenyl)-1-phenylethane, 1,1-bis(4-hydroxy-3-(1-methylethyl)phenyl)-1-phenylethane, 1,1-bis(4-hydroxy-3-tert-butylphenyl)-1-phenylethane, 1,1-bis(4-hydroxy-3-(1-methylpropyl)phenyl)-1-phenylethane, 1,1-bis(4-hydroxy-3-cyclohexylphenyl)-1-phenylethane, 1,1-bis(4-hydroxy-3-cyclohexylphenyl)-1-phenylethane, 1,1-bis(4-hydroxy-3-(1-methylpropyl)phenyl)-1-phenylethane -3-phenylphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclooctane, 4,4'-(1,3-phenylene diisopropylidene)bisphenol, 4,4'-(1,4-phenylene diisopropylidene)bisphenol, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxyphenyl ether, 4,4'-dihydroxybiphenyl, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxy-6-methyl-3-tert-butylphenyl)butane.

[0140] In addition, as an embodiment of other structural units, reference may be made to the structural unit described in paragraph 0008 of International Publication No. 2017 / 099226, the description in paragraphs 0043 to 0052 of International Publication No. 2017 / 099226, and the description in Japanese Patent Application Publication No. 2011-046769, and these contents are incorporated into this specification.

[0141] <<Proportion, physical properties, etc. of structural units of polycarbonate resin (A)>>

[0142] The proportion of the structural unit represented by formula (1) in the polycarbonate resin (A) used in the present embodiment is preferably 10 mol% or more, more preferably 15 mol% or more, further preferably 20 mol% or more, and further preferably 25 mol% or more in all the structural units. The upper limit of the proportion of the structural unit represented by formula (1) in all the structural units is preferably 95 mol% or less, more preferably 85 mol% or less, further preferably 80 mol% or less, further preferably 75 mol% or less, further more preferably 65 mol% or less, and further more preferably 55 mol% or less.

[0143] In addition, the proportion of the structural unit represented by formula (2) in the above-mentioned total structural units is preferably 5 mol% or more, more preferably 15 mol% or more, further preferably 25 mol% or more, more preferably 35 mol% or more, and more preferably 45 mol% or more. In addition, the upper limit of the proportion of the structural unit represented by formula (2) in the above-mentioned total structural units is preferably 90 mol% or less, more preferably 85 mol% or less, further preferably 80 mol% or less, and more preferably 75 mol% or less.

[0144] In the polycarbonate resin (A) used in the present embodiment, the total of the structural units represented by the above formula (1) and the structural units represented by the formula (2) preferably accounts for 90 mol% or more of all the structural units, more preferably accounts for 95 mol% or more, and further preferably accounts for 97 mol% or more. The upper limit of the above total is the ratio of the structural units represented by the formula (1) and the structural units represented by the formula (2) to all the structural units excluding the terminal groups.

[0145] The polycarbonate resin (A) used in the present embodiment is preferably the following: In the present embodiment, (A1) or (A2) is preferred, and (A1) is more preferred.

[0146] (A1) A blend of a polycarbonate resin comprising a structural unit represented by formula (1) and a polycarbonate resin comprising a structural unit represented by formula (2) (particularly a blend of a polycarbonate resin in which 90% by mass or more of all structural units are structural units represented by formula (1) and a polycarbonate resin in which 90% by mass or more of all structural units are structural units represented by formula (2)).

[0147] (A2) A polycarbonate resin comprising a structural unit represented by the formula (1) and a structural unit represented by the formula (2).

[0148] (A3) A blend of a polycarbonate resin comprising a structural unit represented by formula (1) and a polycarbonate resin comprising a structural unit represented by formula (1) and a structural unit represented by formula (2).

[0149] (A4) A blend of a polycarbonate resin comprising a structural unit represented by formula (2) and a polycarbonate resin comprising a structural unit represented by formula (1) and a structural unit represented by formula (2).

[0150] (A5) A blend of a polycarbonate resin comprising a structural unit represented by formula (1), a polycarbonate resin comprising a structural unit represented by formula (2), and a polycarbonate resin comprising a structural unit represented by formula (1) and a structural unit represented by formula (2).

[0151] (A6) In the above (A1) to (A5), the polycarbonate resin or the polycarbonate resin constituting the blend thereof is a polycarbonate resin containing structural units other than the structural unit represented by the formula (1) and the structural unit represented by the formula (2).

[0152] (A7) A blend of the polycarbonate resin or blend of the above-mentioned (A1) to (A6) and a polycarbonate resin containing other structural units.

[0153] The lower limit of the viscosity average molecular weight (Mv) of the (A) polycarbonate resin used in the present embodiment is preferably 5,000 or more, more preferably 8,000 or more, further preferably 10,000 or more, and further preferably 12,000 or more. The upper limit of Mv is preferably 32,000 or less, more preferably 30,000 or less, further preferably 29,000 or less, and further preferably 27,000 or less.

[0154] When two or more polycarbonate resins are contained, it is the sum of the values ​​obtained by multiplying the viscosity average molecular weight of each polycarbonate resin by the mass fraction.

[0155] By making the viscosity average molecular weight above the above lower limit, the moldability can be improved, and a molded product with high mechanical strength can be obtained. In addition, by being below the above upper limit, the fluidity of the molded product is improved, and even a thin-walled molded product can be effectively manufactured.

[0156] The viscosity average molecular weight (Mv) of the polycarbonate resin was calculated from the following Schnell viscosity formula by determining the intrinsic viscosity (η) (unit: dL / g) at 20° C. using an Ubbelohde viscometer using methylene chloride as a solvent.

[0157] η=1.23×10 -4 Mv 0.83

[0158] The method for producing the polycarbonate resin (A) used in the present embodiment is not particularly limited, and for example, the description in paragraphs 0027 to 0043 and Examples of JP-A-2014-065901 can be referred to, and the contents are incorporated into the present specification.

[0159] The content of (A) polycarbonate resin in the resin composition of the present embodiment is preferably 80 mass % or more, more preferably 85 mass % or more, further preferably 90 mass % or more, and more preferably 94 mass % or more. By being above the above lower limit, there is a tendency that the impact strength and heat resistance of the molded product formed by the resin composition are further improved. In addition, the upper limit of the content of (A) polycarbonate resin is preferably the amount of the component other than (B) tris (2,4-di-tert-butylphenyl) phosphate being polycarbonate resin. By being below the above upper limit, there is a tendency that the surface hardness of the molded product formed by the resin composition is improved.

[0160] <(B) Tris(2,4-di-tert-butylphenyl)phosphate>

[0161] In the resin composition of the present embodiment, (B) tris(2,4-di-tert-butylphenyl) phosphate is contained in a ratio of 0.001 to 0.5 parts by mass relative to 100 parts by mass of (A) polycarbonate resin. By containing (B) tris(2,4-di-tert-butylphenyl) phosphate, even when the molded article is subjected to a wet heat treatment, the difference in YI value from the case where the wet heat treatment is not performed can be reduced.

[0162] (B) tris(2,4-di-tert-butylphenyl)phosphate may be directly added to the polycarbonate resin, or may be a component contained in a recycled polycarbonate resin or the like as described above.

[0163] Regarding the content of (B) tris (2,4-di-tert-butylphenyl) phosphate in the resin composition of the present embodiment, it is 0.001 mass parts or more, preferably 0.005 mass parts or more, more preferably 0.01 mass parts or more, and further can be 0.02 mass parts or more, 0.03 mass parts or more, greater than 0.03 mass parts, 0.04 mass parts or more. By being above the above lower limit, the difference between the YI of the wet heat molded product and the YI of the initial molded product can be reduced. In addition, regarding the upper limit of the content of the above-mentioned (B) tris (2,4-di-tert-butylphenyl) phosphate, it is 0.5 mass parts or less, preferably 0.4 mass parts or less, and further can be 0.3 mass parts or less, 0.2 mass parts or less, 0.1 mass parts or less relative to 100 mass parts of (A) polycarbonate resin. By being below the above upper limit, there is a tendency to further reduce the YI of the initial molded product.

[0164] In the resin composition of the present embodiment, the mass ratio (B) / (A-2) of the mass of the structural unit represented by the above formula (1) to the mass of the above (B) tris(2,4-di-tert-butylphenyl) phosphate satisfies 0.00003≤(B) / (A-2)≤0.0050. By making the above (B) / (A-2) above the lower limit, there is a tendency to further reduce ΔYI. In addition, by making the above (B) / (A-2) below the above upper limit, the hardness of the obtained molded product can be increased, and ΔYI can be reduced.

[0165] The above-mentioned (B) / (A-2) is preferably 0.00010 or more, and is preferably 0.0030 or less, more preferably 0.0020 or less, further preferably 0.0010 or less, further preferably 0.00080 or less, and further preferably 0.00060 or less.

[0166] The resin composition of the present embodiment may be a composition that substantially does not contain triaryl phosphates other than tris(2,4-di-tert-butylphenyl)phosphate. Substantially containing means that the content of triaryl phosphates other than tris(2,4-di-tert-butylphenyl)phosphate in the resin composition is preferably 10% by mass or less of the content of tris(2,4-di-tert-butylphenyl)phosphate, more preferably 5% by mass or less, further preferably 3% by mass or less, and further preferably 1% by mass or less.

[0167] <Other ingredients>

[0168] In the resin composition of the present embodiment, other components other than the above may be contained as required as long as the desired various physical properties are not significantly impaired. If other components are given as examples, thermoplastic resins (such as acrylic resins, etc.) other than the above (A) polycarbonate resin, various resin additives, etc. may be given.

[0169] As resin additives, for example, mold release agents, stabilizers (heat stabilizers, antioxidants, etc.), ultraviolet absorbers, antistatic agents, flame retardants, flame retardant aids, dyes, pigments, antifogging agents, antiblocking agents, fluidity improvers, plasticizers, dispersants, antibacterial agents, etc. can be cited. It should be noted that the resin additive may contain one kind, or may contain two or more kinds in any combination and ratio.

[0170] As the antistatic agent, the description in paragraphs 0063 to 0067 of JP-A-2016-216534 may be referred to, and the contents are incorporated into the present specification.

[0171] As the flame retardant, the description in paragraphs 0068 to 0075 of JP-A-2016-216534 may be referred to, and the contents are incorporated into the present specification.

[0172] <<Release Agent>>

[0173] The resin composition of the present embodiment may contain a release agent.

[0174] 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 silicone oils, ketone waxes, and light aminos. Aliphatic carboxylic acids, salts of aliphatic carboxylic acids, and esters of aliphatic carboxylic acids and alcohols are preferred.

[0175] As the aliphatic carboxylic acid, for example, saturated or unsaturated aliphatic monobasic, dibasic or tribasic carboxylic acids can be mentioned. Here, the aliphatic carboxylic acid also includes alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are monobasic or dibasic carboxylic acids having 6 to 36 carbon atoms, and more preferably aliphatic saturated monobasic carboxylic acids having 6 to 36 carbon atoms. Specific examples of the aliphatic carboxylic acid include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetratriacontanoic acid, montanic acid, adipic acid, azelaic acid, etc.

[0176] As the aliphatic carboxylic acid in the ester of aliphatic carboxylic acid and alcohol, for example, the same substances as the above-mentioned aliphatic carboxylic acids can be used. On the other hand, as alcohol, for example, saturated or unsaturated monohydric or polyhydric alcohols can be mentioned. These alcohols may have substituents such as fluorine atoms and aromatic groups. Among these, monohydric or polyhydric saturated alcohols with a carbon number of 30 or less are preferred, and aliphatic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols with a carbon number of 30 or less are further preferred. It should be noted that aliphatic here is used as a term that also includes alicyclic compounds.

[0177] Specific examples of the alcohol include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentyl glycol, ditrimethylolpropane, and dipentaerythritol.

[0178] It should be noted that the above-mentioned ester may also contain aliphatic carboxylic acid and / or alcohol as impurities. In addition, the above-mentioned ester may be a pure substance or a mixture of two or more compounds. In addition, the aliphatic carboxylic acid and alcohol that form one ester through bonding may be used in one kind respectively, or two or more kinds may be used in any combination and ratio.

[0179] Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture containing myricyl palmitate as a main component), stearyl stearate, behenyl behenate, stearyl behenate, glyceryl monopalmitate, glyceryl monostearate, glyceryl distearate, glyceryl tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate, and rice bran wax.

[0180] Examples of aliphatic hydrocarbons having a number average molecular weight of 200 to 15,000 include liquid paraffin, paraffin wax, microcrystalline wax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomers having 3 to 12 carbon atoms. It should be noted that the aliphatic hydrocarbons herein also include alicyclic hydrocarbons. In addition, these hydrocarbons may be partially oxidized.

[0181] Among these, paraffin wax, polyethylene wax or a partial oxide of polyethylene wax is preferred, and paraffin wax and polyethylene wax are more preferred.

[0182] Furthermore, the number average molecular weight of the aliphatic hydrocarbon is preferably 5,000 or less.

[0183] The aliphatic hydrocarbon may be a single substance or a mixture of substances having various constituent components and molecular weights, as long as the main component is within the above range.

[0184] Examples of the polysiloxane-based silicone oil include dimethyl silicone oil, methylphenyl silicone oil, diphenyl silicone oil, and fluoroalkyl silicone.

[0185] For details of the release agent, reference can be made to paragraphs 0055 to 0061 of JP-A-2018-095706, and these contents are incorporated into this specification.

[0186] When the resin composition of the present embodiment contains a release agent, the content of the release agent is preferably 0.05 to 3% by mass, more preferably 0.1 to 0.8% by mass, and even more preferably 0.1 to 0.6% by mass in the resin composition.

[0187] In the resin composition of the present embodiment, the mold release agent may contain only one type or two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0188] <<Stabilizer>>

[0189] Examples of the stabilizer include heat stabilizers and antioxidants.

[0190] Examples of the stabilizer include phenol stabilizers, amine stabilizers, phosphorus stabilizers, thioether stabilizers, etc. Among them, phosphorus stabilizers and phenol stabilizers are preferred in the present embodiment.

[0191] As the phosphorus stabilizer, any known phosphorus stabilizer can be used. Specific examples include phosphorus oxygen acids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; acidic pyrophosphate metal salts such as acidic sodium pyrophosphate, acidic potassium pyrophosphate, and acidic calcium 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 phosphite diester compounds, and organic phosphite compounds are particularly preferred.

[0192] Examples of the organic phosphite compound include triphenyl phosphite, tris(mononylphenyl) phosphite, tris(mononyl / dinonylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, monooctyl diphenyl phosphite, dioctyl monophenyl phosphite, monodecyl diphenyl phosphite, didecyl monophenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, and 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite.

[0193] Specific examples of such organic phosphite compounds include "ADKSTAB (registered trademark, hereinafter the same) 1178", "ADKSTAB 2112", and "ADKSTAB HP-10" manufactured by ADEKA, "JP-351", "JP-360", and "JP-3CP" manufactured by Johoku Chemical Industry Co., Ltd., and "Irgafos (registered trademark, hereinafter the same) 168" manufactured by BASF.

[0194] As the phenolic stabilizer, a hindered phenolic stabilizer is preferably used. Specific examples of the hindered phenolic stabilizer include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, diethylene sulfide bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-(hexane-1,6-diyl)bis[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, 3,3',3",5,5',5"-hexa-tert-butyl-a,a',a"-( trimethylol-2,4,6-triyl) tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis[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-triazine-2-ylamino)phenol, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, etc.

[0195] Among them, 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 stabilizers include "Irganox (registered trademark, hereinafter the same) 1010" and "Irganox 1076" manufactured by BASF, and "ADKSTAB AO-50" and "ADKSTAB AO-60" manufactured by ADEKA.

[0196] The content of the stabilizer in the resin composition of the present 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, relative to 100 parts by mass of the (A) polycarbonate resin. By making the content of the stabilizer within the above range, the effect of adding the stabilizer can be more effectively exerted.

[0197] In the resin composition of the present embodiment, the stabilizer may be contained in one type or in two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0198] The resin composition of the present embodiment can be adjusted so that the total amount of (A) the polycarbonate resin, (B) tris(2,4-di-tert-butylphenyl)phosphate, and other components blended as necessary is 100% by mass.

[0199] <Physical Properties of Resin Composition>

[0200] The resin composition of the present embodiment preferably has a low YI (initial YI) when it is made into a molded product. Specifically, the YI when the resin composition of the present embodiment is molded into a 3 mm thick test piece is preferably 2.50 or less, more preferably 2.30 or less, and further preferably 2.05 or less. It is ideal that the lower limit of the above initial YI is 0, but even if it is 0.10 or more, the required performance can be fully satisfied. Such a low initial YI is achieved by using (B) tris (2,4-di-tert-butylphenyl) phosphate.

[0201] In the resin composition of the present embodiment, the YI (wet heat YI) of the molded article formed by the above resin composition after wet heat treatment is preferably low. The YI (wet heat YI) of a 3 mm thick test piece formed by the resin composition of the present embodiment after wet heat treatment for 100 hours (conditions of 105°C and 100% humidity) using a high pressure cooking tester is preferably 2.55 or less, more preferably 2.30 or less, further preferably 2.20 or less, and even more preferably 2.10 or less. It is ideal that the lower limit of the above wet heat YI is 0, but even if it is 0.10 or more, the required performance can be fully satisfied. Such a low wet heat YI is achieved by using (B) tris(2,4-di-tert-butylphenyl) phosphate.

[0202] In the resin composition of the present embodiment, the difference (ΔYI) between the wet heat YI and the initial YI is preferably 0.23 or less, more preferably 0.20 or less, further preferably 0.19 or less, further preferably 0.15 or less, and further preferably 0.10 or less. It is ideal that the lower limit of the ΔYI is 0, but in practice it is greater than 0. Such a low ΔYI is achieved by using (B) tris(2,4-di-tert-butylphenyl)phosphate.

[0203] The above YI is measured according to the description in the Examples described below.

[0204] <Method for producing resin composition>

[0205] The method for producing the resin composition of the present embodiment is not limited, and a known method for producing the resin composition can be widely adopted, and the following method can be cited: (A) polycarbonate resin and (B) tris (2,4-di-tert-butylphenyl) phosphate, and other components mixed as needed are pre-mixed using various mixers such as a drum mixer and a Henschel mixer, and then melt-kneaded using a mixer such as a Banbury mixer, a roll, a Brabender, a single-screw kneading extruder, a twin-screw kneading extruder, and a kneader. It should be noted that the temperature of the melt kneading is not particularly limited, and is usually in the range of 240 to 320°C.

[0206] <Molding>

[0207] The above-mentioned resin combination (for example pellet) utilizes various molding methods to be molded and is made into molded products. That is, the molded products of the present embodiment are formed by the resin combination of the present embodiment. There is no particular restriction on the shape of the molded products, and it can be appropriately selected according to the use and purpose of the molded products, for example, film-like, rod-like, cylindrical, annular, circular, elliptical, polygonal, special-shaped products, hollow products, frame-like, box-like, panel-like, button-like, etc. can be cited.

[0208] There is no particular restriction on the method for molding the molded product, and existing known molding methods can be adopted, for example, injection molding, injection extrusion molding, extrusion molding, profile extrusion, transfer molding, hollow molding, gas-assisted hollow molding, blow molding, extrusion blow molding, IMC (in-mold coating molding) molding, rotational molding, multilayer molding, two-color molding, insert molding, sandwich molding, foam molding, compression molding, etc. The resin composition of the present embodiment is particularly suitable for the molded product obtained by injection molding, injection extrusion molding, and extrusion molding. However, the resin composition of the present embodiment is certainly not limited to the molded product obtained by these methods.

[0209] The molded article of this embodiment is suitable for use in parts such as electrical and electronic equipment, OA equipment, portable information terminals, machine parts, home appliances, vehicle parts, various containers, lighting equipment, and display screens.

[0210] Example

[0211] The present invention is described in more detail below by enumerating examples. As long as it does not depart from the gist of the present invention, the materials, dosage, ratio, processing content, processing procedures, etc. shown in the following examples can be appropriately changed. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0212] When the measuring equipment used in the examples is difficult to obtain due to discontinuation of production or the like, other equipment having equivalent performance may be used for measurement.

[0213] 1. Raw materials

[0214] The following raw materials shown in Table 1 were used.

[0215] [Table 1]

[0216]

[0217] <Production Example 1: Production of Polycarbonate Resin (A-2)>

[0218] 26.14 mol (6.75 kg) of bisphenol C (BPC) and 26.79 mol (5.74 kg) of diphenyl carbonate were placed in an aluminum (SS) reactor (internal volume 10 liters) equipped with a stirrer and a distillation condenser. After the reactor was replaced with nitrogen, the temperature was raised to 220° C. in a nitrogen atmosphere over 30 minutes.

[0219] Next, the reaction solution in the reactor was stirred, and the concentration of BPC in the molten reaction solution was 1.5×10 -6 Cesium carbonate (Cs2CO3) was added as a catalyst for the transesterification reaction in a molar manner, and the reaction solution was stirred and brewed at 220°C for 30 minutes under a nitrogen atmosphere. Then, the pressure in the reactor was reduced to 100 Torr over 40 minutes at the same temperature, and the reaction was further reacted for 100 minutes to distill off phenol.

[0220] Next, the temperature in the reactor was raised to 284°C over 60 minutes, and the pressure was reduced to 3 Torr, so that the phenol equivalent to the theoretical amount of distillation was distilled out. Next, the pressure in the reactor was kept at less than 1 Torr at this temperature, and the reaction was continued for another 60 minutes to terminate the polycondensation reaction. At this time, the stirring speed of the stirrer was 38 rpm, the temperature of the reaction solution just before the end of the reaction was 289°C, and the stirring power was 0.60 kW.

[0221] Next, the reaction solution in a molten state is fed into a twin-screw extruder, and butyl p-toluenesulfonate in a molar amount of 4 times that of cesium carbonate is fed from the first supply port of the twin-screw extruder and kneaded with the reaction solution. Thereafter, the reaction solution is extruded in the form of strands through the die of the twin-screw extruder and cut with a cutter to obtain pellets of a polycarbonate resin (A-2).

[0222] 2. Examples 1 to 7, Comparative Examples 1 to 6

[0223] Mix the components listed in Table 1 above in the proportions (each component is in parts by mass) listed in Table 2 or Table 3 below. After mixing for 20 minutes using a drum mixer, use a twin-screw extruder (manufactured by Shibaura Machine Co., Ltd., "TEM-26SX") to carry out melt compounding at a barrel temperature of 250°C and a discharge rate of 25 kg / h, and obtain a resin composition (pellets) by strand cutting.

[0224] <Manufacture of test pieces>

[0225] After drying the pellets obtained above at 100°C for 5 hours using a hot air circulation dryer, use an injection molding machine (manufactured by Japan Steel Works, Ltd., "J55AD-60H") to obtain stepped flat test pieces with an area of 90×60 mm, thicknesses of 1 mm, 2 mm, and 3 mm under the conditions of a barrel temperature of 270°C and a mold temperature of 70°C.

[0226] <Method for measuring YI>

[0227] At the 3-mm-thick part of the test piece obtained by the above method, use a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., "SE6000") to measure the yellowness index (YI) based on JIS K7105.

[0228] <Damp heat test>

[0229] After maintaining the test piece for which YI has been measured above in a high-pressure autoclave tester at a temperature of 105°C and a humidity of 100% for 100 hours, measure the YI of the 3-mm part in the same way (YI after damp heat), and calculate ΔYI from the following formula. It should be noted that a high-pressure autoclave tester manufactured by Hirayama Seisakusho Co., Ltd., "PC-304 / 422R8D" is used for the test.

[0230] ΔYI = (YI after damp heat) - (initial YI)

[0231] Calculate the difference ΔYI between the YI after damp heat and the initial YI. The results are shown in Tables 2 to 4.

[0232] <Pencil hardness>

[0233] For the test piece obtained by the above method, according to ISO 15184, use a pencil hardness tester to obtain the pencil hardness measured under a load of 1 kg.

[0234] The pencil hardness tester uses the equipment manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0235] [Table 2]

[0236]

[0237] [Table 3]

[0238]

[0239] In Tables 2 and 3 above, "(B) total amount of tris(2,4-di-tert-butylphenyl)phosphate" is the total amount of tris(2,4-di-tert-butylphenyl)phosphate contained in the resin composition, and represents the amount including the total amount of components contained in the polycarbonate resin in addition to the amount due to the addition of component (B-1).

[0240] In Tables 2 and 3 above, "tris(2,4-di-tert-butylphenyl)phosphate (phosphate) / C-PC mass ratio" represents the ratio (B-1) / (A-2) of the mass of the structural unit represented by formula (1) to the mass of (B) tris(2,4-di-tert-butylphenyl)phosphate.

[0241] From the above results, it can be seen that the initial YI of the molded article formed from the resin composition of the present embodiment is low, and the difference (ΔYI) between the YI value after the wet heat treatment is also small (Examples 1 to 17). In contrast, when tris(2,4-di-tert-butylphenyl)phosphate is not included (Comparative Examples 1 to 4), ΔYI is high.

[0242] In addition, when the mass ratio of tris(2,4-di-tert-butylphenyl)phosphate (phosphate ester) / C-PC is higher than the upper limit of (B) / (A-2) (Comparative Example 5), the pencil hardness of the obtained molded article is low. On the other hand, when the mass ratio of tris(2,4-di-tert-butylphenyl)phosphate (phosphate ester) / C-PC is lower than the upper limit of (B) / (A-2) (Comparative Example 6), the initial YI value is high, and the difference (ΔYI) between the initial YI value and the YI value after the wet heat treatment is also large.

Claims

1. A resin composition comprising 0.001 to 0.5 parts by mass of (B) tris(2,4-di-tert-butylphenyl)phosphate relative to 100 parts by mass of (A) polycarbonate resin, wherein the (A) polycarbonate resin comprises a structural unit represented by formula (1), in, In the resin composition, the ratio of the mass of the structural unit represented by the formula (1) to the mass of the (B) tris(2,4-di-tert-butylphenyl) phosphate (B) / (A-2) satisfies 0.00003≤(B) / (A-2)≤0.0050, Formula (1) [Chemistry 1] In formula (1), R 1 Represents methyl, R 2 represents a hydrogen atom or a methyl group, X 2 represents any of the following, [Chemistry 2] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group which bonds to C to form an alicyclic hydrocarbon which may have a substituent and has 6 to 12 carbon atoms.

2. The resin composition according to claim 1, in, The (A) polycarbonate resin contains the structural unit represented by the formula (1) in a ratio of 10 mol % to 95 mol % in all structural units.

3. The resin composition according to claim 1, in, The (A) polycarbonate resin contains the structural unit represented by the formula (1) in a ratio of 10 mol % to 80 mol % in all structural units.

4. The resin composition according to any one of claims 1 to 3, in, The (A) polycarbonate resin further comprises a structural unit represented by formula (2), Formula (2) [Chemistry 3] In formula (2), X 1 represents any of the following, [Chemistry 4] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group which bonds to C to form an alicyclic hydrocarbon which may have a substituent and has 6 to 12 carbon atoms.

5. The resin composition according to claim 4, in, The polycarbonate resin (A) containing the structural unit represented by the formula (2) includes a recycled product.

6. The resin composition according to claim 5, in, The ratio of the recycled product in the polycarbonate resin (A) is 5% by mass to 80% by mass.

7. The resin composition according to claim 1, in, The (A) polycarbonate resin further comprises a structural unit represented by formula (2), The polycarbonate resin containing the structural unit represented by the formula (2) includes a recycled product. Formula (2) [Chemistry 5] In formula (2), X 1 represents any of the following, [Chemistry 6] R 3 and R 4 Each independently represents a hydrogen atom or a methyl group, and Z represents a group which bonds to C to form an alicyclic hydrocarbon which may have a substituent and has 6 to 12 carbon atoms.

8. Pellets of the resin composition according to any one of claims 1 to 3 and 7.

9. A molded article formed from the resin composition according to any one of claims 1 to 3 and 7.

10. A molded article formed from the pellets according to claim 8.

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