Regenerated polycarbonate resin composition

Abstract

To provide regenerated polycarbonate resin compositions that have the same physical properties as unused polycarbonate resin compositions, using recycled polycarbonate resin.SOLUTION: There is provided a regenerated polycarbonate resin composition containing: 0.01 to 0.5 pts. mass of a phosphorus-based antioxidant based on 100 pts. mass of the resin component consisting of 1 to 90 mass% of an unused polycarbonate resin (a1) and 99 to 10 mass% of a recovered polycarbonate resin (a2), wherein a diphenyl carbonate content of the recovered polycarbonate resin (a2) is 20 ppm or less, and a chlorobenzene content of the recovered polycarbonate resin is 20 ppm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a recycled polycarbonate resin composition. [Background technology]

[0002] Polycarbonate resins and other resins have excellent mechanical properties, electrical properties, weather resistance, water resistance, chemical resistance and solvent resistance, and are therefore used in a variety of applications, including electrical and electronic components, machine mechanism components and automotive components.

[0003] In recent years, recycling has been strongly demanded from the viewpoint of environmental protection. For example, Patent Document 1 discloses a method for recovering thermoplastic resin from products using thermoplastic resin, in which thermoplastic resin members recovered from equipment parts are crushed, washed, and then the crushed material is separated to produce recycled materials. Examples of recycled polycarbonate resin materials include recycled materials regenerated from optical disks such as CDs, DVDs, and BDs, light guide plates, automobile window glass, and automobile headlamp lenses.

[0004] However, recycled materials contain various additives in various amounts, and it has been difficult to obtain a recycled material that is close to a polycarbonate resin composition that does not use recycled materials using only recycled materials. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-198116 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a recycled polycarbonate resin composition using recycled polycarbonate resin and having physical properties equivalent to those of a virgin polycarbonate resin composition. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the present inventors have found that by mixing recovered polycarbonate resin having a diphenyl carbonate content of 20 ppm or less and a chlorobenzene content of 20 ppm or less with virgin polycarbonate resin, a recycled polycarbonate resin composition having physical properties equivalent to those of a virgin polycarbonate resin composition, in particular excellent hydrolysis resistance, can be obtained, thereby completing the present invention.

[0008] That is, the present invention (1) comprises 0.01 to 0.5 parts by mass of a phosphorus-based antioxidant per 100 parts by mass of a resin component consisting of 1 to 90% by mass of a virgin polycarbonate resin (a1) and 99 to 10% by mass of a recovered polycarbonate resin (a2), The recycled polycarbonate resin (a2) is a recycled polycarbonate resin composition having a diphenyl carbonate content of 20 ppm or less and a chlorobenzene content of 20 ppm or less.

[0009] The present invention (2) relates to the recycled polycarbonate resin composition according to the present invention (1), in which the content of the virgin polycarbonate resin (a1) is 10 to 80 mass % and the content of the recycled polycarbonate resin (a2) is 90 to 20 mass %.

[0010] The present invention (3) relates to the recycled polycarbonate resin composition according to the present invention (1) or (2), in which the viscosity average molecular weight of the recycled polycarbonate resin (a2) is 17,000 to 28,000.

[0011] The present invention (4) is a recycled polycarbonate resin composition according to any one of the present inventions (1) to (3), in which the tris(2,4-di-t-butylphenyl)phosphate content of the recycled polycarbonate resin (a2) is 20 ppm or less and the 2,4-di-t-butylphenol content is 50 ppm or less.

[0012] The present invention (5) is a recycled polycarbonate resin composition according to any one of the present inventions (1) to (4), in which the recycled polycarbonate resin (a2) has a content of at least one ultraviolet absorber selected from benzotriazole-based, benzophenone-based, and triazine-based ultraviolet absorbers of 2000 ppm or less.

[0013] The present invention (6) is a recycled polycarbonate resin composition according to any one of the present inventions (1) to (5), in which the content of diphenyl carbonate in the composition is 10 ppm or less and the content of chlorobenzene is 2 ppm or less.

[0014] The present invention (7) is the recycled polycarbonate resin composition according to any one of the present inventions (1) to (6), in which the content of diphenyl carbonate in the composition is 5 ppm or less.

[0015] The present invention (8) is a recycled polycarbonate resin composition according to any one of the present inventions (1) to (7), in which the tris(2,4-di-t-butylphenyl)phosphate content in the composition is 10 ppm or less and the 2,4-di-t-butylphenol content is 20 ppm or less.

[0016] The present invention (9) is a recycled polycarbonate resin composition according to any one of the present inventions (1) to (8), in which the content of at least one ultraviolet absorber selected from benzotriazole-based, benzophenone-based, and triazine-based ultraviolet absorbers in the composition is 5,000 ppm or less.

[0017] The present invention (10) is a recycled polycarbonate resin composition according to any one of the present inventions (1) to (9), in which the difference in haze between before and after a reliability test in which a 2 mm-thick injection-molded piece is kept in an autoclave at 120°C and 100% RH for 48 hours is 5.0 or less. Effect of the Invention

[0018] The recycled polycarbonate resin composition of the present invention contains virgin polycarbonate resin together with recovered polycarbonate resin having a diphenyl carbonate content of 20 ppm or less and a chlorobenzene content of 20 ppm or less. Therefore, despite using recycled polycarbonate resin, a recycled polycarbonate resin composition having physical properties (hydrolysis resistance) equivalent to those of a resin composition using virgin polycarbonate resin can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The embodiments will be described in detail below. However, more detailed explanations than necessary may be omitted. For example, detailed explanations of already well-known matters or duplicate explanations of substantially the same configurations may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the inventors provide the following explanations to enable those skilled in the art to fully understand the present invention, and do not intend to limit the subject matter described in the claims.

[0020] The recycled polycarbonate resin composition of the present invention is characterized in that it contains 0.01 to 0.5 parts by mass of a phosphorus-based antioxidant per 100 parts by mass of a resin component consisting of 1 to 90% by mass of virgin polycarbonate resin (a1) and 99 to 10% by mass of recycled polycarbonate resin (a2), and that the recycled polycarbonate resin (a2) has a diphenyl carbonate content of 20 ppm or less and a chlorobenzene content of 20 ppm or less.

[0021] The virgin polycarbonate resin (a1) used in the present invention refers to a resin that has been pelletized after polymerization and has not been processed into various molded products. The virgin polycarbonate resin (a1) is a polymer obtained by the phosgene method in which various dihydroxydiaryl compounds are reacted with phosgene, or the ester exchange method in which dihydroxydiaryl compounds are reacted with carbonate esters such as diphenyl carbonate, and a representative example is a polycarbonate resin produced from 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A).

[0022] Examples of dihydroxydiaryl compounds include, in addition to bisphenol A, bis(hydroxyaryl)alkanes such as bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxyphenyl-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, and 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane; bis(hydroxyaryl)cycloalkanes such as 1,1-bis(4-hydroxyphenyl)cyclopentane and 1,1-bis(4-hydroxyphenyl)cyclohexane; dihydroxydiaryl ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether; dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide; dihydroxydiaryl sulfoxides such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; and dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone.

[0023] These may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidylhydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, etc. may also be used in combination.

[0024] Furthermore, the above dihydroxyaryl compounds may be used in combination with the following trivalent or higher phenolic compounds: Trivalent or higher phenolic compounds include phloroglucin, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptene, 2,4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane, 1,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,1-tri-(4-hydroxyphenyl)-ethane, and 2,2-bis-[4,4-(4,4'-dihydroxydiphenyl)-cyclohexyl]-propane.

[0025] The viscosity average molecular weight of the virgin polycarbonate resin (a1) is not particularly limited, but from the viewpoints of moldability and strength, it is usually 18000 to 25000. When producing such a polycarbonate resin, a molecular weight regulator, a catalyst, etc. may be used as necessary.

[0026] The recovered polycarbonate resin (a2) used in the present invention is recovered from a molded article of a polycarbonate resin composition. Examples of the molded article include molded articles formed by various molding methods such as injection molding, compression molding, extrusion molding, blow molding, and calendar molding. More specific uses of the molded article include headlamps, front covers of pachinko machines, silicon wafer cases, transport containers, polycarbonate sheets, ballpoint pens, and the like. Among them, polycarbonate resin compositions recovered from silicon wafer cases and polycarbonate sheets are preferred. These recovered polycarbonate resin compositions can also be used by mixing a plurality of recovered polycarbonate resin compositions.

[0027] The diphenyl carbonate content in the recovered polycarbonate resin (a2) is 20 ppm or less, preferably 15 ppm or less. If it exceeds 20 ppm, the decomposition of the polycarbonate resin composition is promoted in a reliability test, and the transparency is impaired. In addition, the chlorobenzene content in the recovered polycarbonate resin (a2) is 20 ppm or less, more preferably 15 ppm or less, and even more preferably 2 ppm or less. If these contents exceed 20 ppm, the decomposition of the polycarbonate resin composition is promoted in a reliability test, and the transparency is impaired.

[0028] The tris(2,4-di-t-butylphenyl)phosphate content in the recovered polycarbonate resin (a2) is preferably 20 ppm or less, more preferably 10 ppm or less, and the 2,4-di-t-butylphenol content is preferably 50 ppm or less, more preferably 40 ppm or less.

[0029] The content of at least one ultraviolet absorbent selected from benzotriazole-based, benzophenone-based and triazine-based ultraviolet absorbents contained in the recovered polycarbonate resin (a2) is preferably 2000 ppm or less, more preferably 1000 ppm or less.

[0030] Examples of the benzotriazole-based ultraviolet absorbers include 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2-(2-hydroxy-3,5-dicumylphenyl)phenylbenzotriazole, 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, riazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-amylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-4-octoxyphenyl)benzotriazole, 2,2'-methylenebis(4-cumyl-6-benzotriazolephenyl), 2,2'-p-phenylenebis(1,3-benzoxazin-4-one), and the like are exemplified.

[0031] Benzophenone-based ultraviolet absorbents include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, and the like.

[0032] Examples of triazine-based ultraviolet absorbers include 2,4-diphenyl-6-(2-hydroxyphenyl-4-hexyloxyphenyl)-1,3,5-triazine, 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol, and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]phenol. For example, TINUVIN 1577 manufactured by BASF is commercially available.

[0033] The content of the phosphorus-based antioxidant contained in the recovered polycarbonate resin (a2) is preferably 5000 ppm or less, more preferably 2000 ppm or less. The phosphorus-based antioxidant may be the phosphorus-based antioxidant described below. The lower limit of the content of the phosphorus-based antioxidant is preferably 100 ppm or more, more preferably 300 ppm or more.

[0034] Examples of the phosphorus-based antioxidant include phosphite compounds having the following phosphite structure. [ka]

[0035] Examples of the phosphorus-based antioxidant include a phosphite compound represented by the following formula (11), a phosphite compound represented by the following formula (12), a phosphite compound represented by the following formula (13), and a phosphite compound represented by the following formula (14).

[0036] Equation (11): [ka] (In the formula, R 1 represents an alkyl group having 1 to 20 carbon atoms, and a represents an integer of 0 to 3.

[0037] In the formula (11), R 1 is an alkyl group having 1 to 20 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms.

[0038] Examples of the compound represented by formula (11) include triphenyl phosphite, tricresyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, and trisnonylphenyl phosphite. Among these, tris(2,4-di-t-butylphenyl) phosphite is particularly suitable. Examples of commercially available products include Irgafos 168 manufactured by BASF ("Irgafos" is a registered trademark of BASF Societas Europea).

[0039] Equation (12): [ka] (In the formula, R 2 , R 3 , R 5 and R 6 R each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group. 4 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; X represents a single bond, a sulfur atom, or a group represented by the formula: -CHR 7 - (where R 7 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. A represents an alkylene group having 1 to 8 carbon atoms or a group represented by the formula: *-COR 8 - (where R 8 represents a single bond or an alkylene group having 1 to 8 carbon atoms, and * represents a bond on the oxygen side. Either Y or Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

[0040] In formula (12), R 2 , R 3 , R 5 and R 6 each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a phenyl group.

[0041] Here, examples of the alkyl group having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, t-pentyl, i-octyl, t-octyl, and 2-ethylhexyl groups. Examples of the cycloalkyl group having 5 to 8 carbon atoms include cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of the alkylcycloalkyl group having 6 to 12 carbon atoms include 1-methylcyclopentyl, 1-methylcyclohexyl, and 1-methyl-4-i-propylcyclohexyl groups. Examples of the aralkyl group having 7 to 12 carbon atoms include benzyl, α-methylbenzyl, and α,α-dimethylbenzyl groups.

[0042] R 2 , R 3 and R 5 are each preferably independently an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or an alkylcycloalkyl group having 6 to 12 carbon atoms. 2 and R 5 are each preferably independently a t-alkyl group such as a t-butyl group, a t-pentyl group, or a t-octyl group, a cyclohexyl group, or a 1-methylcyclohexyl group. 3 is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, or a t-pentyl group, and more preferably a methyl group, a t-butyl group, or a t-pentyl group.

[0043] R 6 is preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms, and more preferably a hydrogen atom, or an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, or a t-pentyl group.

[0044] In formula (12), R4 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include the above-mentioned R 2 , R 3 , R 5 and R 6 In particular, R 4 is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom or a methyl group.

[0045] In formula (12), X represents a single bond, a sulfur atom, or a group represented by the formula: -CHR 7 -, where the formula is -CHR 7 -R in 7 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a cycloalkyl group having 5 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms and the cycloalkyl group having 5 to 8 carbon atoms include the above-mentioned R 2 , R 3 , R 5 and R 6 In particular, X is preferably a single bond, a methylene group, or a methylene group substituted with a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, or the like, and more preferably a single bond.

[0046] In formula (12), A is an alkylene group having 1 to 8 carbon atoms or a group represented by the formula: *-COR 8 Examples of the alkylene group having 1 to 8 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentamethylene group, a hexamethylene group, an octamethylene group, and a 2,2-dimethyl-1,3-propylene group, and the like, with a propylene group being preferred. 8 -R in 8 R represents a single bond or an alkylene group having 1 to 8 carbon atoms. 8 Examples of the alkylene group having 1 to 8 carbon atoms represented by the formula (I) include the alkylene groups exemplified in the description of A above. 8is preferably a single bond or an ethylene group. 8 The * in - is a bond on the oxygen side, indicating that the carbonyl group is bonded to the oxygen atom of the phosphite group.

[0047] In formula (12), one of Y and Z represents a hydroxyl group, an alkoxy group having 1 to 8 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms, and the other represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkoxy group having 1 to 8 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a t-butoxy group, and a pentyloxy group. Examples of the aralkyloxy group having 7 to 12 carbon atoms include a benzyloxy group, an α-methylbenzyloxy group, and an α,α-dimethylbenzyloxy group. Examples of the alkyl group having 1 to 8 carbon atoms include the above-mentioned R 2 , R 3 , R 5 and R 6 Examples of the alkyl group include those exemplified in the explanation of the above.

[0048] Examples of the compound represented by formula (12) include 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine, 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepine, Examples of such compounds include 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-4,8-di-t-butyl-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, etc. Among these, 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine is preferred when the resulting aromatic polycarbonate resin composition is used in a field that requires optical properties. An example of a commercially available product is Sumilizer GP ("Sumilizer" is a registered trademark) manufactured by Sumitomo Chemical Co., Ltd.

[0049] Equation (13): [ka] (In the formula, R 9 and R 10 each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group which may be substituted with an alkyl group, and b and c each independently represent an integer of 0 to 3.

[0050] Examples of the compound represented by formula (13) include bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, phenyl bisphenol A pentaerythritol diphosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, etc. As a commercially available product, ADK STAB PEP-36 manufactured by ADEKA CORPORATION ("ADK STAB" is a registered trademark) is commercially available.

[0051] Equation (14): [ka]

[0052] (In the formula, R 11 ~R 18 R each independently represents an alkyl group or an alkenyl group having 1 to 3 carbon atoms. 11 and R 12 , R 13 and R 14 , R 15 and R 16 , R 17 and R 18 may be bonded to each other to form a ring. 19 ~R 22 each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. each of d to g independently represents an integer of 0 to 5. X 1 ~X 4 Each of X independently represents a single bond or a carbon atom. 1 ~X 4 is a single bond, R 11 ~R 22 Among these, the functional group connected to the single bond is excluded from general formula (14).

[0053] A specific example of the compound represented by formula (14) is bis(2,4-dicumylphenyl)pentaerythritol diphosphite. A commercially available product is Doverphos (registered trademark) S-9228 manufactured by Dover Chemical Co.

[0054] Further examples of phosphorus-based antioxidants include [1,1'-biphenyl]-4,4'-diylbis[bis(2,4-di-t-butylphenoxy)phosphine], etc. Commercially available products include, for example, Irgaphos P-EPQ (trade name) manufactured by BASF and HOSTANOX P-EPQ (trade name) manufactured by Clariant Chemicals.

[0055] The content of the non-phosphorus antioxidant contained in the recovered polycarbonate resin (a2) is preferably 5000 ppm or less, more preferably 2000 ppm or less. Examples of the non-phosphorus antioxidant include phenolic antioxidants such as dibutylhydroxytoluene, butylhydroxytoluene, and 2,6-di-tert-butyl-4-(N,N-dimethylaminomethyl)phenol.

[0056] The content of the lubricant contained in the recovered polycarbonate resin (a2) is preferably 10000 ppm or less, more preferably 8000 ppm or less. Examples of the lubricant include glycerin monostearate and pentaerythritol tetrastearate.

[0057] The melt volume rate (MVR) of the recovered polycarbonate resin (a2) is preferably from 3 to 30, more preferably from 10 to 20. Here, the MVR is measured in accordance with ISO1133 using a melt flow indexer under conditions of 300° C. and a load of 1.2 kg.

[0058] The viscosity average molecular weight of the recovered polycarbonate resin (a2) is not particularly limited, but is preferably from 17,000 to 28,000, more preferably from 18,000 to 25,000, from the standpoints of moldability and strength.

[0059] The content of the virgin polycarbonate resin (a1) is 1 to 90 mass%, preferably 10 to 80 mass%, and more preferably 20 to 70 mass%, based on 100 mass% of the total of the virgin polycarbonate resin (a1) and the recovered polycarbonate resin (a2). On the other hand, the content of the recovered polycarbonate resin (a2) is 99 to 10 mass%, preferably 90 to 20 mass%, and more preferably 80 to 30 mass%.

[0060] The content of diphenyl carbonate in the recycled polycarbonate resin composition of the present invention is preferably 10 ppm or less, more preferably 5 ppm or less, and the content of chlorobenzene is preferably 2 ppm or less, more preferably 1 ppm or less.

[0061] The content of tris(2,4-di-t-butylphenyl)phosphate in the composition is preferably 10 ppm or less, more preferably 5 ppm or less, and the content of 2,4-di-t-butylphenol in the composition is preferably 30 ppm or less, more preferably 20 ppm or less.

[0062] The content of at least one ultraviolet absorbent selected from benzotriazole-based, benzophenone-based and triazine-based ultraviolet absorbents in the composition is preferably 5000ppm or less, more preferably 3000ppm or less.If it exceeds 5000ppm, it is not preferable because it deteriorates the color tone.In addition, although the ultraviolet absorbent may remain in the recovered polycarbonate resin, the content is preferably 2000ppm or less.

[0063] The content of phosphorus-based antioxidant in the composition is preferably 1000 ppm or less, more preferably 500 ppm or less. The content of non-phosphorus-based antioxidant in the composition is preferably 1000 ppm or less, more preferably 500 ppm or less. The content of lubricant in the composition is preferably 10000 ppm or less, more preferably 8000 ppm or less.

[0064] The recycled polycarbonate resin composition of the present invention may contain additives such as heat stabilizers, colorants, release agents, softeners, antistatic agents, impact modifiers, UV absorbers, pigments, fillers, and flow improvers, as long as the effects of the additives are not impaired.

[0065] Examples of the filler include carbon black, glass fiber, and mica.

[0066] The recycled polycarbonate resin composition of the present invention is characterized in that the difference in haze between before and after a reliability test in which a 2 mm thick injection molded piece is held in an autoclave at 120°C and 100% RH for 48 hours is 5.0 or less. The difference in haze is preferably 2.0 or less.

[0067] The melt volume rate (MVR) of the recycled polycarbonate resin composition of the present invention is preferably 3 to 30, more preferably 10 to 20. Here, the MVR is measured using a melt flow indexer under conditions of 300° C. and a load of 1.2 kg in accordance with ISO1133.

[0068] The recycled polycarbonate resin composition of the present invention uses recycled polycarbonate resin, and can provide a recycled polycarbonate resin composition having the same physical properties as a virgin polycarbonate resin composition, and therefore can be suitably applied to electric / electronic parts, automobile parts, or machine mechanism parts. EXAMPLES

[0069] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" are based on mass.

[0070] The following raw materials were used: Unused polycarbonate resin: Sumika Polycarbonate Co., Ltd. SD Polyca 200-13, viscosity average molecular weight 21500 Recycled polycarbonate resin; PCR-A (recovered PC from wafer cases), viscosity average molecular weight 19,300 PCR-B (a composition of PC recovered from wafer cases (60%) and PC recovered from sheets (40%)), viscosity average molecular weight 20,200 PCR-C (PC recovered from sheet), viscosity average molecular weight 22,100 PCR-D (PC recovered from transport container), viscosity average molecular weight 20,100 PCR-E (recovered PC from pachinko machines), viscosity average molecular weight 20,600 PCR-F (PC recovered from headlights), viscosity average molecular weight 19,300 PCR-G (PC recovered from headlights), viscosity average molecular weight 21,200

[0071] <Analysis of Recycled Polycarbonate Resin> The antioxidants were analyzed as follows. First, polycarbonate resin was dissolved in dichloromethane, methanol was added dropwise to reprecipitate the polymer component, and the solution was filtered. The filtrate was then placed in a 100 ml eggplant flask. The filtrate in the eggplant flask was then evaporated to dryness using a rotary evaporator, and 20 ml of methanol was added to prepare a measurement solution. The solution was analyzed by high performance liquid chromatography to determine the content of various antioxidants.

[0072] The ultraviolet absorbent was analyzed as follows: The polycarbonate resin was dissolved in dichloromethane, and the absorbance of this solution at 340 nm to 350 nm was measured with an ultraviolet-visible-near infrared spectrophotometer to determine the content of the ultraviolet absorbent.

[0073] The lubricants were analyzed as follows. First, polycarbonate resin was dissolved in dichloromethane, methanol was added dropwise to reprecipitate the polymer component, and the solution was filtered. The filtrate was then placed in a 100 ml recovery flask. The filtrate in the recovery flask was then evaporated to dryness using a rotary evaporator, and 20 ml of methanol was added to prepare a measurement solution. The solution was analyzed by LC / MS to determine the content of various lubricants.

[0074] The PC impurities tris(2,4-di-t-butylphenyl)phosphate and 2,4-di-t-butylphenol were analyzed as follows. First, polycarbonate resin was dissolved in dichloromethane, methanol was added dropwise to reprecipitate the polymer component, and the solution was filtered. The filtrate was then placed in a 100 ml eggplant flask. The filtrate in the eggplant flask was then evaporated to dryness using a rotary evaporator, and 10 ml of methanol was added to prepare a measurement solution. The content of tris(2,4-di-t-butylphenyl)phosphate and 2,4-di-t-butylphenol was determined by analyzing this solution using LC / MS.

[0075] The PC impurities, chlorobenzene and diphenyl carbonate, were analyzed as follows. First, polycarbonate resin was dissolved in dichloromethane, and the solution was introduced into a pyrolysis furnace and heated to about 200°C. The resulting volatile components were cooled and collected with liquid nitrogen. The cooled and collected components were then separated and analyzed by GC / MS to determine the contents of chlorobenzene and diphenyl carbonate.

[0076] The results of these analyses are shown in Table 1. Here, ND means not detected. The compound names of each component detected are shown below.

[0077] [Phenol-based antioxidants] BHT: Dibutyl hydroxytoluene AO-50 (ADEKA Corporation): n-Octadecyl-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate

[0078] [Phosphorus-based antioxidants] PEP-36 (ADEKA Corporation): Bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite P-EPQ (BASF): [1,1'-biphenyl]-4,4-diylbis[bis(2,4-di-tert-butylphenoxy)phosphine] P-168 (BASF): Tris(2,4-di-tert-butylphenyl)phosphite Doverphos S-9228: Bis(2,4-dicumylphenyl)pentaerythritol diphosphite

[0079] [Benzotriazole-based UV absorbers] Tinuvin 329 (BASF): 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-2-phenol LA-31 (ADEKA Corporation): 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol]

[0080] [Lubricant] GMS: Glycerin monostearate (Riken Vitamin Co., Ltd.) PETS: Pentaerythritol tetrastearate (Emily Oleochemicals Japan Co., Ltd.)

[0081] [PC impurities] Tris(2,4-di-t-butylphenyl)phosphate (Sigma-Aldrich Co. LLC) 2,4-Di-t-butylphenol (Tokyo Chemical Industry Co., Ltd.) Chlorobenzene (FUJIFILM Wako Pure Chemical Corporation) Diphenyl carbonate (Tokyo Chemical Industry Co., Ltd.)

[0082] <Melt Volume Rate (MVR)> The recovered polycarbonate resin was dried at 100°C for 4 hours, and then the melt volume rate (MVR) was measured in accordance with ISO1133 under conditions of 300°C and a load of 1.2 kg using a melt flow indexer (120-SAS-1 manufactured by Yasuda Seiki Seisakusho Co., Ltd.).

[0083] [Table 1]

[0084] Examples 1 to 5 and Comparative Examples 1 to 4 The various ingredients were mixed in a tumbler with the ingredients and ratios shown in Table 1, and melt-kneaded at a cylinder temperature of 280°C using a 37mm diameter twin-screw extruder (TEM37SS manufactured by Shibaura Machine Co., Ltd.) to obtain various pellets. Using the obtained pellets, MVR measurement and analysis of the content of impurities such as chlorobenzene were performed using the methods described above, and the reliability test shown below was also performed. The results are shown in Table 2.

[0085] <Reliability test> The obtained recycled polycarbonate resin composition was molded using an injection molding machine (J100 E2P manufactured by Japan Steel Works, Ltd.) with a cylinder temperature set at 320°C and a mold temperature set at 100°C. The obtained molded article was kept in an autoclave under an environment of 120°C and 100% RH for 48 hours. Using the molded article before and after the keeping, the haze (unit: %) was measured according to JIS K7136 using a NDH-2000 type haze meter manufactured by Nippon Denshoku Industries Co., Ltd., and the difference in haze was calculated.

[0086] [Table 2]

[0087] As shown in Table 2, in the recycled polycarbonate resin compositions of Examples 1 to 5, the chlorobenzene and diphenyl carbonate contents of the recycled polycarbonate resin were 20 ppm or less and 20 ppm or less, respectively, so that the ΔHaze before and after the reliability test was 5.0 or less. On the other hand, in the recycled polycarbonate resin compositions of Comparative Examples 1 to 4, the chlorobenzene and diphenyl carbonate contents of the recycled polycarbonate resin were 20 ppm or more, respectively, so that the ΔHaze before and after the reliability test was 5.0 or more, and the reliability was poor. [Industrial Applicability]

[0088] The recycled polycarbonate resin composition of the present invention, although made from recycled polycarbonate resin, has excellent reliability tests, is environmentally friendly, and has high industrial value.

Claims

1. The composition contains 0.01 to 0.5 parts by mass of a phosphorus-based antioxidant relative to 100 parts by mass of a resin component consisting of 1 to 90% by mass of a virgin polycarbonate resin (a1) and 99 to 10% by mass of a recovered polycarbonate resin (a2), A recycled polycarbonate resin composition, characterized in that the recovered polycarbonate resin (a2) has a diphenyl carbonate content of 20 ppm or less and a chlorobenzene content of 20 ppm or less.

2. The recycled polycarbonate resin composition according to claim 1, wherein the content of the virgin polycarbonate resin (a1) is 10 to 80% by mass, and the content of the recycled polycarbonate resin (a2) is 90 to 20% by mass.

3. The recycled polycarbonate resin composition according to claim 1 or 2, wherein the viscosity average molecular weight of the recycled polycarbonate resin (a2) is 17,000 to 28,000.

4. The recycled polycarbonate resin composition according to claim 1 or 2, wherein the tris(2,4-di-t-butylphenyl)phosphate content of the recycled polycarbonate resin (a2) is 20 ppm or less and the 2,4-di-t-butylphenol content is 50 ppm or less.

5. The recycled polycarbonate resin composition according to claim 1 or 2, wherein the recycled polycarbonate resin (a2) contains 2000 ppm or less of at least one ultraviolet absorber selected from benzotriazole-based, benzophenone-based and triazine-based ultraviolet absorbers.

6. The recycled polycarbonate resin composition according to claim 1 or 2, wherein the content of diphenyl carbonate in the composition is 10 ppm or less and the content of chlorobenzene in the composition is 2 ppm or less.

7. The recycled polycarbonate resin composition according to claim 1 or 2, wherein the content of diphenyl carbonate in the composition is 5 ppm or less.

8. The recycled polycarbonate resin composition according to claim 1 or 2, wherein the tris(2,4-di-t-butylphenyl)phosphate content in the composition is 10 ppm or less and the 2,4-di-t-butylphenol content is 20 ppm or less.

9. The recycled polycarbonate resin composition according to claim 1 or 2, wherein the content of at least one ultraviolet absorber selected from benzotriazole-based, benzophenone-based, and triazine-based ultraviolet absorbers in the composition is 5,000 ppm or less.

10. The recycled polycarbonate resin composition according to claim 1 or 2, in which the difference in haze before and after a reliability test in which a 2 mm thick injection-molded piece is kept in an autoclave at 120°C and 100% RH for 48 hours is 5.0 or less.

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