JP2016056385A - Polycarbonate resin composition, molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition capable of being a material for a molded body capable of maintaining excellent impact resistance at low temperature for long time even by repeated use under high temperature and high humidity environment and hardly generating discoloration or the like even retained at high temperature, and a molded body made of the resin composition.SOLUTION: There is provided the polycarbonate resin composition which contains : (A) an aromatic polycarbonate resin mixture containing 5 to 100 mass% of (A-1) an aromatic polycarbonate-polyorganosiloxane copolymer and 95 to 0 mass% of (A-2) an aromatic polycarbonate resin other than the (A-1) component with the content of a polyorganosiloxane unit of 1 mass% or more; and with respect to 100 pts.mass of the (A) aromatic polycarbonate resin mixture, 0.002 to 0.200 pts.mass of (B) a phosphorus-based antioxidant and 0 to 0.200 pts.mass of (C) an epoxidation stabilizer and which has a reduction percentage P of viscosity average molecular weight before and after a pressure cooker test calculated by the calculation formula (I) of 20% or less.SELECTED DRAWING: None

Description

  The present invention relates to a polycarbonate resin composition and a molded article comprising the resin composition.

  For example, an aromatic polycarbonate resin composition containing an aromatic polycarbonate-polyorganosiloxane copolymer (hereinafter also referred to as “PC-POS copolymer”) as disclosed in Patent Document 1 is used in a low-temperature environment. It becomes a material for molded products with excellent impact resistance.

  On the other hand, logistics supplies and containers used in refrigerated warehouses are often washed with hot water or high-temperature steam before they are put into a low-temperature warehouse. Performance that can withstand below is also required.

JP 2010-215791 A

Polycarbonate resin composition containing PC-POS copolymer is excellent in impact resistance under low temperature environment, but hydrolyzed under high temperature and high humidity environment to lower molecular weight and impact resistance performance at low temperature There is a problem that it will drop to. For example, if logistics goods and containers used in a refrigerated warehouse that repeatedly perform hot water and steam cleaning, etc., are manufactured with a polycarbonate resin composition containing PC-POS copolymer, hydrolysis will occur while repeated hot water and steam cleaning, etc. As a result, the low-temperature impact performance deteriorates. As a result, it is pointed out that containers made of the resin composition are inferior in long-term durability because the logistics supplies and containers rarely break in a freezer warehouse.
Therefore, there is a demand for a polycarbonate resin composition that can be used as a molding material that can maintain impact resistance at low temperatures for a long period of time, even when washing is repeated using warm water or steam, and the molecular weight does not decrease due to hydrolysis. It was rare.

  The present invention has been made in view of the above problems, and can be a material for a molded body that can maintain excellent low temperature impact resistance performance for a long period of time even when used repeatedly in a high temperature and high humidity environment. Another object of the present invention is to provide a polycarbonate resin composition having a processing stability that hardly causes discoloration or the like even if it stays in an injection molding machine, and a molded body made of the resin composition.

  The inventors of the present invention do not cause a flat plate sample manufactured using a specific polycarbonate resin composition to undergo a pressure cooker test under a predetermined condition, and then perform an automatic falling weight impact test under a predetermined condition so as not to brittlely break. As a result of searching for conditions, it was found that a polycarbonate resin composition containing a specific amount of a specific component and having a decrease rate of the viscosity average molecular weight before and after the pressure cooker test is not more than a specific value can solve the above problems. Completed the invention.

That is, the present invention provides the following [1] to [10].
[1] Aromatic polycarbonate-polyorganosiloxane copolymer (A-1) 5 to 100% by mass, and aromatic polycarbonate resin (A-2) other than component (A-1) 95 to 0% by mass, For 100 parts by mass of the aromatic polycarbonate resin mixture (A) having a polyorganosiloxane unit content of 1% by mass or more, 0.002 to 0.200 parts by mass of the phosphorus-based antioxidant (B), epoxidation stability Agent (C) is a polycarbonate resin composition containing 0 to 0.200 parts by mass, and the decrease rate P of the viscosity average molecular weight of the polycarbonate resin composition calculated from the following calculation formula (I) is 20% or less Polycarbonate resin composition.
Calculation formula (I): P [%] = (M ₁ −M ₂ ) / M ₁ × 100
(In the above formula (I), M ₁ is the viscosity average molecular weight of the resin composition measured after making the polycarbonate resin composition into pellets, and M ₂ is a pressure cooker in which the pellets are set at 121 ° C. It represents the viscosity average molecular weight of the resin composition after the pressure cooker test, measured after being put into a testing machine for 300 hours, and P is the viscosity average molecular weight of the resin composition before the pressure cooker test. It represents the rate of decrease in viscosity average molecular weight of the resin composition after the test.)
[2] The polycarbonate resin composition according to the above [1], wherein the resin composition after the pressure cooker test represented by M ₂ in the calculation formula (I) has a viscosity average molecular weight of 16000 or more.
[3] The polycarbonate resin composition according to [1] or [2] above, wherein the phosphorus antioxidant (B) is a phosphite antioxidant or a phosphine antioxidant.
[4] When the phosphorus-based antioxidant (B) is a phosphite-based antioxidant and the resin composition does not substantially contain the (C) component, the content of the (B) component is (A) The polycarbonate resin composition according to any one of [1] to [3], which is 0.002 to 0.020 parts by mass with respect to 100 parts by mass of the component.
[5] When the phosphorus-based antioxidant (B) is a phosphine-based antioxidant, the resin composition does not substantially contain the component (C), and is any one of the above [1] to [3]. Polycarbonate resin composition.
[6] The epoxidation stabilizer (C) is 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate and / or 2,2-bis (hydroxymethyl) -1-butanol. The polycarbonate resin composition according to any one of [1] to [3] above, which is a 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct.
[7] The polycarbonate resin composition according to any one of [1] to [3], wherein the epoxidized stabilizer (C) is an epoxidized natural oil or an epoxidized synthetic oil having an oxirane oxygen concentration of 4% or more. .
[8] A molded product comprising the polycarbonate resin composition according to any one of [1] to [7].
[9] The molded product according to [8], wherein the molded product is a product or a part that is washed with warm water of 90 ° C. or higher and / or steam of 100 ° C. or higher.
[10] The molded product according to [8] or [9], wherein the molded product is a product or a part used in an environment having a temperature of 60 ° C. or higher and a relative humidity of 90% or higher.

  The polycarbonate resin composition of the present invention is excellent in processing stability in which discoloration or the like hardly occurs even if it stays in an injection molding machine, and a molded product that has been molded can be used even if it is repeatedly used in a high temperature and high humidity environment. It is possible to suppress a decrease in molecular weight due to hydrolysis of the resin molded product and maintain impact resistance at low temperatures over a long period of time.

[Polycarbonate resin composition]
The polycarbonate resin composition of the present invention (hereinafter also simply referred to as “resin composition”) is an aromatic polycarbonate-polyorganosiloxane copolymer (A-1) (hereinafter referred to as “PC-POS copolymer (A-1)”. ) ") And an aromatic polycarbonate resin mixture (A-2) other than the component (A-1) (hereinafter also referred to as" other PC resin (A-2) ") ( A) A polycarbonate resin composition obtained by adding a specific part by mass of a specific phosphorus-based antioxidant (B) and a specific epoxidation stabilizer to 100 parts by mass. The resin composition of the present invention has the following characteristics.

  That is, in the resin composition of the present invention, the rate of decrease P of the viscosity average molecular weight of the polycarbonate resin composition calculated from the following calculation formula (I) is 20% or less, preferably 18% or less, more preferably 16% or less. This is a polycarbonate resin composition.

Calculation formula (I): P [%] = (M ₁ −M ₂ ) / M ₁ × 100
(In the above formula (I), M ₁ is the viscosity average molecular weight of the resin composition measured after making the polycarbonate resin composition into pellets, and M ₂ is a pressure cooker in which the pellets are set at 121 ° C. It represents the viscosity average molecular weight of the resin composition after the pressure cooker test, measured after being put into a testing machine for 300 hours, and P is the viscosity average molecular weight of the resin composition before the pressure cooker test. It represents the rate of decrease in viscosity average molecular weight of the resin composition after the test.)
In the present invention, the above-mentioned pellets are granular to an average representative length of about 0.1 to 20 mm after melting and / or kneading the resin composition of the present invention using an extruder or the like. Is processed.

The value of P in the above formula is the hydrolysis after the resin composition of the present invention is kneaded into pellets (further molded products) and the pellets or molded products are subjected to a pressure cooker test at 121 ° C. for 300 hours. It represents the rate of decrease in viscosity average molecular weight due to.
Molded products obtained by molding such a resin composition have a low molecular weight drop due to hydrolysis, even when used repeatedly in high temperature and high humidity environments such as steam cleaning and hot water cleaning. Therefore, a highly safe molded product can be obtained. For this reason, the charged molecular weight of the resin composition can be reduced, and fluidity that can be easily processed into a molded body can be obtained.

  On the other hand, when a molded product molded using a resin composition having a viscosity-average molecular weight reduction rate P of more than 20% is used, the molecular weight is accelerated when steam cleaning or hot water cleaning is repeated. . In order to compensate for the low-temperature impact performance drop caused by the molecular weight reduction, it is necessary to increase the initial molecular weight too much. However, as the molecular weight is increased, molding processability decreases, It tends to be difficult. Further, when the molecular weight is lowered, mechanical properties such as tensile properties, bending properties, and creep properties are also lowered, so that the strength tends to be insufficient even for static loads such as stacking. Further, the decrease in molecular weight tends to cause whitening of the molded product, bleeding of the additive, and the like, so that the appearance is deteriorated.

Moreover, the viscosity average molecular weight of the resin composition (pellet) after the pressure cooker test represented by M ₂ in the calculation formula (I) is preferably 16000 or more, more preferably 17000 or more, and further preferably 18000. That's it. If the said viscosity average molecular weight is 16000 or more, it can apply as materials, such as a distribution goods for a frozen warehouse which performs a steam washing | cleaning, a container. Note that if the resin composition has a viscosity average molecular weight of 18000 or more after the pressure cooker test, a molded product obtained by processing the resin composition may be brittlely broken even under severe impact. Almost disappear. For example, using this resin composition, 20 test plates having a thickness of 2 mm as shown in the examples were molded, subjected to a pressure cooker test at 121 ° C. for 300 hours, and then subjected to an automatic falling weight impact at −30 ° C. Even if it tests, it becomes all ductile fracture.
In addition, although there is no restriction | limiting in particular as an upper limit of the said viscosity average molecular weight, Usually, it is 80000 or less, Preferably it is 60000 or less.

  The resin composition having both hydrolysis resistance and low-temperature impact properties as described above is achieved by the following constitution.

<Aromatic polycarbonate resin mixture (A)>
A resin composition contains the resin mixture (A) which consists of a PC-POS copolymer (A-1) and another PC resin (A-2).
The content of the PC-POS copolymer (A-1) is preferably 5 to 100% by mass, more preferably 20 to 95% by mass, and still more preferably 50 to 90% by mass with respect to the total amount of the component (A). %.
On the other hand, the content of the PC resin (A-2) is preferably 0 to 95% by mass, more preferably 5 to 80% by mass, and still more preferably 10 to 50% by mass with respect to the total amount of the component (A). is there.
Further, the content of the polyorganosiloxane unit in the total amount of the component (A) is 1% by mass or more, preferably in the range of 1.5 to 30% by mass, more preferably in the range of 2 to 20% by mass, and still more preferably. Is in the range of 3-15% by mass. When the content of the polyorganosiloxane unit is less than 1% by mass, the impact resistance performance under a low temperature environment is, for example, that of logistics goods and containers used in a freezing warehouse or the like in an atmosphere of −30 ° C. or lower. It does not increase to the level of low temperature impact performance required as a material.

The molecular weight when the resin composition is prepared is such that the content of the polyorganosiloxane unit in the total amount of the component (A) is 1% by mass or more, and the rate of decrease in the viscosity average molecular weight after the pressure cooker test is 20%. The molecular weight of the charge as the resin composition is not particularly limited as long as it is a composition that is not more than%, but is usually 80,000 or less, preferably 60000 or less.
Hereinafter, the component (A-1) and the component (A-2) will be described in detail.

(PC-POS copolymer (A-1))
As the PC-POS copolymer (A-1) contained in the resin composition of the present invention, a polycarbonate part (PC part) composed of a structural unit represented by the following general formula (I), and the following general formula ( The copolymer containing the polyorganosiloxane part (POS part) which consists of a structural unit represented by II) is preferable.

In the general formula (I), R ¹ and R ² each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, -S-, -SO- , _-SO 2 -, - indicating O- or -CO- a. a and b each independently represent an integer of 0 to 4.
Moreover, in said general formula (II), R < ³ > -R < ⁶ > is respectively independently a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, or C6-C12. An aryl group of Y represents an organic residue containing an aliphatic group or an aromatic group. n is the average number of repetitions and represents a number of 20 to 1000.

In general formula (I), examples of the alkyl group independently represented by R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups (“various” means And the like, and the same applies hereinafter), various pentyl groups, various hexyl groups, and the like.
Examples of the alkoxy group independently represented by R ¹ and R ² include groups in which the alkyl group moiety is the alkyl group.
Examples of the alkylene group represented by X include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a hexamethylene group, and an alkylene group having 1 to 5 carbon atoms is preferable.
Examples of the alkylidene group represented by X include an ethylidene group and an isopropylidene group.
Examples of the cycloalkylene group represented by X include a cyclopentanediyl group, a cyclohexanediyl group, and a cyclooctanediyl group, and a cycloalkylene group having 5 to 10 carbon atoms is preferable.
Examples of the cycloalkylidene group represented by X include a cyclohexylidene group, a 3,5,5-trimethylcyclohexylidene group, a 2-adamantylidene group, and the like, and a cycloalkylidene group having 5 to 10 carbon atoms is preferable. A cycloalkylidene group having 5 to 8 carbon atoms is more preferable.
a and b each independently represent an integer of 0 to 4, preferably 0 to 2, more preferably 0 or 1.

In general formula (II), examples of the halogen atom independently represented by R ^{3 to} R ⁶ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkyl group and alkoxy group independently represented by R ^{3 to} R ⁶ include the same groups as those for R ¹ and R ² .
As an aryl group which R < ³ > -R < ⁶ > shows each independently, a phenyl group, a naphthyl group, etc. are mentioned, for example.
As an organic residue containing the aliphatic which Y shows, a C1-C10 (preferably C1-C6, more preferably C1-C3) alkylene group etc. are mentioned, for example.
Examples of the organic residue containing an aromatic group represented by Y include arylene groups having 6 to 12 ring carbon atoms such as a phenylene group, a naphthylene group, and a biphenyldiyl group.

  The average repeating number n of the POS part in the general formula (II) is 20 to 1000, preferably 30 to 600, more preferably 35 to 250, and still more preferably 40 to 150. If n is 20 or more, impact resistance at low temperatures can be sufficiently improved. Moreover, if it is 1000 or less, there is no problem about the handleability of POS and it is preferable from a viewpoint on manufacture of a PC-POS copolymer. In addition, the value of this average repetition number n is a value calculated by nuclear magnetic resonance (NMR) measurement.

The content of the structural unit (PC part) represented by the general formula (I) is preferably 70 to 98% by mass, more preferably 85 to 97.5 in the PC-POS copolymer (A-1). It is 90 mass%, More preferably, it is 90-97 mass%.
On the other hand, the content of the structural unit (POS part) represented by the general formula (II) is preferably 1 to 30% by mass, more preferably 2 to 20 in the PC-POS copolymer (A-1). % By mass, more preferably 3 to 15% by mass. If it is 1% by mass or more, the effect of improving impact strength is sufficient, while if it is 30% by mass or less, sufficient heat resistance is obtained.
The content of the structural unit in the PC-POS copolymer is a value calculated by nuclear magnetic resonance (NMR) measurement.

  The viscosity average molecular weight of the PC-POS copolymer (A-1) is preferably 12000 to 70000, more preferably 14000 to 50000, from the viewpoint of the balance between the strength of the molded product and the productivity. Preferably it is 16000-30000.

  As a manufacturing method of the PC-POS copolymer having the structural units represented by the above general formulas (I) and (II), a dihydric phenol represented by the following general formula (1) and the following general formula (2) It is preferable to obtain by copolymerizing a polyorganosiloxane represented by) and phosgene, carbonate, or chloroformate.

Here, in the general formula (1), ^{R 1} and ^R 2, X, a and b are the same as the above general formula (I), the general formula ^{(2), R 3 ~R 6} , Y, n Is the same as in the general formula (II), m represents 0 or 1, Z represents halogen, —R ⁷ OH, —R ⁷ COOH, —R ⁷ NH ₂ , —COOH or —SH; ⁷ represents a linear, branched or cyclic alkylene group, an aryl-substituted alkylene group, an aryl-substituted alkylene group which may have an alkoxy group on the ring, or an arylene group.

The dihydric phenol represented by the general formula (1) is not particularly limited, but 2,2-bis (4-hydroxyphenyl) propane [common name: bisphenol A] is preferable. When bisphenol A is used as the dihydric phenol, in the general formula (I), X is an isopropylidene group and a PC-POS copolymer having a = b = 0 is obtained.
Examples of dihydric phenols other than bisphenol A include 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, bis (4-hydroxyphenyl) diphenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4- Hydroxyphenyl) naphthylmethane, 1,1-bis (4-hydroxy-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-) 3,5-tetramethylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophene) Bis (hydroxyaryl) alkanes such as propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,5,5-trimethylcyclohexane, 2, Bis (hydroxyaryl) cycloalkanes such as 2-bis (4-hydroxyphenyl) norbornane and 1,1-bis (4-hydroxyphenyl) cyclododecane, 4,4′-dihydroxyphenyl ether, 4,4′-dihydroxy Dihydroxy aryl ethers such as 3,3′-dimethylphenyl ether, 4,4′-di Droxydiphenyl sulfide, dihydroxydiaryl sulfides such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide, 4,4′-dihydroxydiphenyl sulfoxide, 4,4′-dihydroxy-3,3′-dimethyldiphenyl Dihydroxy diaryl sulfoxides such as sulfoxide, 4,4'-dihydroxydiphenyl sulfone, dihydroxy diaryl sulfones such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone, dihydroxy such as 4,4'-dihydroxydiphenyl Dihydroxy diarylfluorenes such as diphenyls, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, bis (4-hydroxyphenyl) diphenylme Dihydroxydiaryl such as 1,3-bis (4-hydroxyphenyl) adamantane, 2,2-bis (4-hydroxyphenyl) adamantane, 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane Adamantanes, 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol, 10,10-bis (4-hydroxyphenyl) -9-anthrone, 1,5-bis (4-hydroxyphenyl) Thio) -2,3-dioxapentaene and the like.
These dihydric phenols may be used alone or in admixture of two or more.

  The polyorganosiloxane represented by the general formula (2) is a phenol having an olefinically unsaturated carbon-carbon bond, preferably vinylphenol, allylphenol, eugenol, isopropenylphenol, or the like having a predetermined average repeat number n. It can be easily produced by subjecting the end of a polyorganosiloxane chain having a hydrosilation reaction. The phenols are more preferably allylphenol or eugenol. In this case, Y in the general formula (II) is an organic residue derived from allylphenol or eugenol.

  Examples of the polyorganosiloxane represented by the general formula (2) include compounds represented by the following general formulas (3) to (11).

In the general formulas (3) to (11), R ^{3 to} R ⁶ are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms, 6 represents an alkoxy group having 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and n represents an average number of repeating units of the organosiloxane constituent unit and represents a number of 20 to 1000. R ⁸ represents an alkyl, alkenyl, aryl or aralkyl group, c represents a positive integer, and is usually an integer of 2 to 6.
Among these, from the viewpoint of ease of polymerization, a phenol-modified polyorganosiloxane represented by the general formula (3) is preferable. In terms of availability, α, ω-bis [3- (o-hydroxyphenyl) propyl] polydimethylsiloxane, which is a kind of the compound represented by the general formula (4), is represented by the general formula (5). Α, ω-bis [3- (4-hydroxy-3-methoxyphenyl) propyl] polydimethylsiloxane, which is one of the compounds shown, is preferred.

The phenol-modified polyorganosiloxane can be produced by a known method. As a manufacturing method, the method shown below is mentioned, for example.
First, cyclotrisiloxane and disiloxane are reacted in the presence of an acidic catalyst to synthesize α, ω-dihydrogenorganopolysiloxane. At this time, α, ω-dihydrogenorganopolysiloxane having a desired average repeating unit can be synthesized by changing the charging ratio of cyclotrisiloxane and disiloxane. Next, in the presence of a hydrosilylation reaction catalyst, the α, ω-dihydrogenorganopolysiloxane is subjected to an addition reaction with a phenol compound having an unsaturated aliphatic hydrocarbon group such as allylphenol or eugenol. A phenol-modified polyorganosiloxane having an average repeating unit can be produced.
Further, at this stage, since low molecular weight cyclic polyorganosiloxane and an excessive amount of the phenol compound remain as impurities, it is preferable to distill off these low molecular compounds by heating under reduced pressure.

(Other PC resin (A-2))
The resin mixture (A) may contain another PC resin (A-2) which is an aromatic polycarbonate other than the component (A-1).
Other PC resins (A-2) include tertiary amines or quaternary ammonium salts after reacting with a dihydric phenol compound and phosgene in the presence of an organic solvent inert to the reaction and an aqueous alkali solution. Conventional aromatic polycarbonate, such as interfacial polymerization method in which polymerization catalyst is added and polymerized, or pyridine method in which dihydric phenol compound is dissolved in pyridine or a mixed solution of pyridine and inert solvent and phosgene is introduced directly Those obtained by the production method can be used.

  Examples of the dihydric phenol compound used in the production of the component (A-2) aromatic polycarbonate include 2,2-bis (4-hydroxyphenyl) propane [common name: bisphenol A], bis (4-hydroxy). Phenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) Phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) naphthylmethane, 1,1-bis (4-hydroxy-3) -T-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propa 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, 2,2-bis (4-hydroxy-3,5) -Dichlorophenyl) propane, bis (hydroxyaryl) alkanes such as 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1 -Bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,5,5-trimethylcyclohexane, 2,2-bis (4-hydroxyphenyl) norbornane, 1,1-bis ( Bis (hydroxyaryl) cycloalkanes such as 4-hydroxyphenyl) cyclododecane, 4,4′-dihydroxyphenol Ethers, dihydroxyaryl ethers such as 4,4′-dihydroxy-3,3′-dimethylphenyl ether, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide, etc. Dihydroxydiaryl sulfoxides, 4,4′-dihydroxydiphenyl sulfoxide, dihydroxydiaryl sulfoxides such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide, 4,4′-dihydroxydiphenyl sulfone, 4,4′- Dihydroxy diaryl sulfones such as dihydroxy-3,3′-dimethyldiphenyl sulfone, dihydroxy diphenyls such as 4,4′-dihydroxydiphenyl, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bi Dihydroxydiarylfluorenes such as (4-hydroxy-3-methylphenyl) fluorene, bis (4-hydroxyphenyl) diphenylmethane, 1,3-bis (4-hydroxyphenyl) adamantane, 2,2-bis (4-hydroxyphenyl) ) Adamantane, dihydroxydiaryladamantanes such as 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane, 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol, 10 , 10-bis (4-hydroxyphenyl) -9-anthrone, 1,5-bis (4-hydroxyphenylthio) -2,3-dioxapentaene and the like. These dihydric phenols may be used alone or in admixture of two or more.

In producing the aromatic polycarbonate as the component (A-2), a molecular weight regulator, a terminal terminator, and the like may be used as necessary. Any of these can be used as long as they are usually used for polymerization of polycarbonate resin.
Specific molecular weight regulators include, for example, monohydric phenols such as phenol, on-butylphenol, mn-butylphenol, pn-butylphenol, o-isobutylphenol, m-isobutylphenol, and p-isobutylphenol. , Ot-butylphenol, mt-butylphenol, pt-butylphenol, on-pentylphenol, mn-pentylphenol, pn-pentylphenol, on-hexylphenol, mn -Hexylphenol, pn-hexylphenol, pt-octylphenol, o-cyclohexylphenol, m-cyclohexylphenol, p-cyclohexylphenol, o-phenylphenol, m-phenylphenol, p-phenylphenol, o n-nonylphenol, m-nonylphenol, pn-nonylphenol, o-cumylphenol, m-cumylphenol, p-cumylphenol, o-naphthylphenol, m-naphthylphenol, p-naphthylphenol, 2,5 -Di-t-butylphenol, 2,4-di-t-butylphenol, 3,5-di-t-butylphenol, 2,5-dicumylphenol, 3,5-dicumylphenol, p-cresol, bromophenol, Tribromophenol, monoalkylphenol having a linear or branched alkyl group having an average carbon number of 12 to 35 in the ortho, meta or para position, 9- (4-hydroxyphenyl) -9- (4-methoxyphenyl) ) Fluorene, 9- (4-hydroxy-3-methylphenyl) -9- (4-methoxy 3-methylphenyl) fluorene, 4- (1-adamantyl) phenol, and the like.
Among these monohydric phenols, pt-butylphenol, p-cumylphenol, p-phenylphenol and the like are preferable. Moreover, these compounds can be used individually or in combination of 2 or more types.

  As the terminal terminator, monovalent carboxylic acid and derivatives thereof, or monovalent phenol can be used. Examples of such a terminal terminator include p-tert-butyl-phenol, p-phenylphenol, p-cumylphenol, p-perfluorononylphenol, p- (perfluorononylphenyl) phenol, p- (perfluorocarbon). Fluoroxylphenyl) phenol, p-tert-perfluorobutylphenol, 1- (P-hydroxybenzyl) perfluorodecane, p- [2- (1H, 1H-perfluorotridodecyloxy) -1,1,1,3 , 3,3-hexafluoropropyl] phenol, 3,5-bis (perfluorohexyloxycarbonyl) phenol, perfluorododecyl p-hydroxybenzoate, p- (1H, 1H-perfluorooctyloxy) phenol, 2H, 2H, 9H-perfluorononanoic acid, 1, , 1,3,3,3 Tetorafuroro-2-propanol.

Furthermore, a branched polycarbonate can be obtained by using a branching agent for the above dihydric phenol compound. The addition amount of the branching agent is preferably 0.01 to 3.0 mol%, more preferably 0.1 to 2.0 mol%, based on the dihydric phenol compound.
Examples of the branching agent include 1,1,1-tris (4-hydroxyphenyl) ethane and 4,4 ′-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl. ] Ethylidene] bisphenol, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, 1- [α-methyl-α- (4′-hydroxyphenyl) ethyl] Examples thereof include compounds having three or more functional groups such as -4- [α ′, α′-bis (4 ″ -hydroxyphenyl) ethyl] benzene, phloroglysin, trimellitic acid, and isatin bis (o-cresol).

  As a viscosity average molecular weight of other PC resin (A-2), Preferably it is 15000-80000, More preferably, it is 16000-60000, More preferably, it is 17000-35000. (A-2) As a component, the viscosity average molecular weight of the resin composition obtained can be adjusted to a desired range by using PC resin which has various viscosity average molecular weights.

<Phosphorus antioxidant (B)>
The resin composition of the present invention contains a phosphorus-based antioxidant (B). By including the phosphorus-based antioxidant (B), even if the resin composition stays at a high temperature during the molding process, the resin composition is provided with excellent processing stability that can suppress discoloration, silver generation, and the like. Can do.
As the phosphorus-based antioxidant, a phosphite-based antioxidant or a phosphine-based antioxidant is preferable from the viewpoint of obtaining a resin composition that can suppress the occurrence of discoloration and the like even when staying at a high temperature.

Examples of the phosphite antioxidant include trisnonylphenyl phosphite, triphenyl phosphite, tridecyl phosphite, trioctadecyl phosphite, tris (2,4-di-t-butylphenyl) phosphite (BASF) Trade name “Irgafos168”, etc.), bis- (2,4-di-t-butylphenyl) pentaerythritol diphosphite (trade name “Irgafos126” manufactured by BASF Corporation), trade name “ADEKA STAB PEP-24G manufactured by ADEKA Corporation” ), Bis- (2,4-di-t-butyl-6-methylphenyl) ethyl phosphite (trade name “Irgafos38” manufactured by BASF, etc.), bis- (2,6-di-t-butyl) -4-methylphenyl) pentaerythritol diphosphite (made by ADEKA) Trade name “Adeka Stub PEP-36”, etc.), distearyl-pentaerythritol-diphosphite (trade name “Adeka Stub PEP-8” manufactured by ADEKA, trade name “JPP-2000” manufactured by Johoku Chemical Co., Ltd.), etc. 2,4-di-t-butyl-5-methylphenoxy) phosphino] biphenyl (trade name “GSY-P101” manufactured by Osaki Kogyo Co., Ltd.), 6- [3- (3-t-butyl-4-hydroxy -5-methylphenyl) propoxy] -2,4,8,10-tetra-t-butyldibenz [d, f] [1,3,2] dioxafospine (trade name “Sumilizer GP manufactured by Sumitomo Chemical Co., Ltd.) N, N-bis [2-[[2,4,8,10-tetrakis (1,1dimethylethyl) dibenzo [d, f] [1,3,2] dioxa Sufepin -6-yl] oxy] - ethyl] ethanamine (BASF Co., Ltd. under the trade name "Irgafos12" etc.) and the like.
In addition, compounds represented by the following formulas (12) to (15) may be mentioned.

  Among these phosphite antioxidants, tris-2,4-di-tert-butylphenyl phosphite is preferable from the viewpoint of hydrolysis resistance.

Examples of the phosphine antioxidant include triphenylphosphine (“JC263” manufactured by Johoku Chemical Co., Ltd.).
In this invention, when using a phosphine antioxidant as (B) component, the epoxidation stabilizer which is (C) component is not substantially contained in a resin composition. The reason for this is that (1) the phosphine antioxidant does not have hydrolyzability, so that it is not necessary to add the component (C), and (2) the phosphine antioxidant and the epoxidation stabilizer (C). By the interaction with the above, the decrease rate of the viscosity average molecular weight of the resin composition after the pressure cooker described above becomes large, it becomes difficult to adjust the decrease rate, (3) by the interaction with the component (C), When the resin composition is retained at a high temperature during the molding process, silver or the like is generated, and the processing stability is lowered.
In the present invention, “substantially free of component (C)” means that the content of component (C) is less than 0.001 part by mass, preferably 0.0001, per 100 parts by mass of component (A). It means less than parts by mass (the same is true in the following description).

  Content of phosphorus antioxidant (B) is 0.002-0.200 mass part with respect to 100 mass parts of (A) component, Preferably it is 0.003-0.100 mass part, More preferably Is 0.003 to 0.080 parts by mass. If the amount is less than 0.002 parts by mass, discoloration of the resin composition and generation of silver when staying at a high temperature cannot be sufficiently suppressed. On the other hand, if it exceeds 0.200 parts by mass, the rate of decrease in the viscosity average molecular weight after the pressure cooker test becomes large, and it becomes difficult to adjust the rate of decrease.

  When the phosphite antioxidant is used as the component (B) and the resin composition does not substantially contain the component (C), the content of the phosphite antioxidant used as the component (B) is: It is 0.002-0.020 mass part with respect to 100 mass parts, Preferably it is 0.003-0.015 mass part, More preferably, it is 0.003-0.012 mass part. When the content of the phosphite antioxidant exceeds 0.020 parts by mass when the component (C) is not substantially contained, the phosphite antioxidant hydrolyzate has a great influence on the resin composition, It becomes difficult to adjust the rate of decrease in the viscosity average molecular weight after the pressure cooker test to a predetermined value or less. That is, when the content of the phosphite antioxidant is 0.020 parts by mass or less, the rate of decrease in the viscosity average molecular weight of the resin composition after the pressure cooker test is not more than a predetermined value without including the component (C). Can be adjusted.

  In addition, when using a phosphite type antioxidant as the (B) component and including the (C) component in the resin composition, or when using a phosphine type antioxidant as the (B) component, the (B) component As described above, the content of the antioxidant to be used is 0.002 to 0.200 parts by mass, preferably 0.003 to 0.100 parts by mass with respect to 100 parts by mass of the component (A). Preferably it is 0.003-0.080 mass part.

<Epoxidation stabilizer (C)>
When the phosphite type antioxidant is used as the component (B), the resin composition of the present invention basically preferably contains an epoxidation stabilizer (C).
Phosphite-based antioxidants are more easily hydrolyzed than polycarbonate resins in a humid heat environment, and further, degradation products such as phosphoric acids and phenols generated by hydrolysis significantly promote the hydrolysis of polycarbonate resins. There is.
The component (B) is an important component from the viewpoint of processing stability and service stability, and the resin composition requires a certain amount or more. However, when the component (B) is a phosphite antioxidant for the above reason, The amount added is limited to 0.020 parts by mass or less.
Therefore, as a result of intensive studies on a method for suppressing hydrolysis of the phosphite antioxidant, the present inventors have suppressed the hydrolysis of the phosphite antioxidant to the epoxidation stabilizer (C), or The present inventors have found that a phosphite antioxidant has an action of detoxifying a decomposition product generated by hydrolysis. From this viewpoint, even when 0.020 parts by mass or more of the phosphite antioxidant is added to the polycarbonate resin (A), if the epoxidation stabilizer (C) is used in combination, the rate of decrease in the viscosity average molecular weight can be reduced. It was possible to adjust to a predetermined value or less.

Examples of the epoxidation stabilizer (C) include compounds in which a part of the structure is epoxidized.
Among such epoxidized stabilizers (C), 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate (trade name “Celoxide 2021P manufactured by Daicel Chemical Industries, Ltd.” is used from the above viewpoint. , Etc.), 2,2-bis (hydroxymethyl) -1-butanol and 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct (trade name “EHPE3150” manufactured by Daicel Chemical Industries, Ltd.), These two kinds of mixtures (trade name EHPE3150CE manufactured by Daicel Chemical Industries, Ltd.) and epoxidized natural oil or epoxidized synthetic oil having an oxirane oxygen concentration of 4% or more are preferred.
Furthermore, when using the molded body made of the resin composition as a food container or the like, from the viewpoint of forming a molded body that can safely store food, epoxidized natural oil or epoxidized synthetic having an oxirane oxygen concentration of 4% or more Oil is more preferred.

Examples of the epoxidized natural oil having an oxirane oxygen concentration of 4% or more include Sanso Sizer E-2000H (trade name, manufactured by Shin Nippon Rika Co., Ltd., epoxidized soybean oil, oxirane oxygen concentration of 6.7% or more), Sanso Sizer E-9000H (trade name, manufactured by Shin Nippon Rika Co., Ltd., epoxidized linseed oil, oxirane oxygen concentration of 8.5% or more) and the like.
Examples of the epoxidized synthetic oil having an oxirane oxygen concentration of 4% or more include, for example, Sansosizer E-PO (trade name, manufactured by Shin Nippon Rika Co., Ltd., epoxyhexahydrophthalic acid diepoxy stearyl, oxirane oxygen concentration 5.5% The above), Sansosizer E-4030 (trade name, manufactured by Shin Nippon Chemical Co., Ltd., epoxidized fatty acid butyl, oxirane oxygen concentration of 4.5% or more) and the like.

  The oxirane oxygen concentration of the epoxidized natural oil or epoxidized synthetic oil is 4% or more, preferably 5% or more, more preferably 6% or more, and further preferably 7% or more. When the oxirane oxygen concentration is less than 4%, the hydrolysis of the phosphite-based antioxidant is suppressed, or the effect of detoxifying the decomposition product generated by the hydrolysis is low, and as a result, the hydrolysis of the polycarbonate can be suppressed. Therefore, it is difficult to adjust the molecular weight reduction rate to a predetermined value or less.

  In addition, the said oxirane oxygen concentration means the value measured using the acetic acid solution of hydrogen bromide based on the rule of ASTM-1652.

Content of an epoxidation stabilizer (C) is 0-0.200 mass part with respect to 100 mass parts of (A) component. If the content exceeds 0.200 parts by mass, the fluidity of the polycarbonate resin composition will increase, or it may cause burns or silver during molding.
In addition, when using a phosphine-based antioxidant having no hydrolyzability as the component (B), a decomposition product that promotes hydrolysis of the polycarbonate resin, such as a phosphite-based antioxidant, is not generated. The addition of agent (C) is not necessary. Since the epoxidation stabilizer (C) and the phosphine antioxidant are both highly active compounds, a phosphine antioxidant is used as the component (B) in order not to cause an unnecessary reaction between them. Is preferably substantially free of component (C).
When the phosphine antioxidant is used as the component (B), the content of the component (C) is preferably less than 0.001 part by mass, more preferably 0.0001 with respect to 100 parts by mass of the component (A). Less than part by mass.

  In addition, when using a phosphite-based antioxidant having hydrolyzability as the component (B), the content of the component (C) is a predetermined value of the rate of decrease in the viscosity average molecular weight after pressure cooker of the obtained resin composition. From the viewpoint of adjusting to the following, 0.002 to 0.200 parts by mass, preferably 0.01 to 0.100 parts by mass, more preferably 0.015 to 0.050 with respect to 100 parts by mass of component (A). Part by mass.

<Other additives>
In the resin composition of the present invention, in addition to the components (A) to (C) described above, various known conventional additives that are conventionally added to the polycarbonate resin composition, as long as the effects of the present invention are not impaired. It is possible to add these additives.
These additives include reinforcing materials, fillers, stabilizers, antioxidants, UV absorbers, antistatic agents, lubricants, mold release agents, dyes, pigments, flame retardants and elastomers for improving impact resistance. Can be mentioned.

〔Molding〕
A molded article made of the polycarbonate resin composition of the present invention can be obtained by molding and kneading the above components.
The kneading method is not particularly limited, and examples thereof include a method using a ribbon blender, a Henschel mixer, a Banbury mixer, a drum tumbler, a single screw extruder, a twin screw extruder, a kneader, a multi screw extruder, and the like. . Moreover, the heating temperature at the time of kneading | mixing is 240-330 degreeC normally, Preferably it is selected in 250-320 degreeC.
As the molding method, conventionally known various molding methods can be used, for example, injection molding method, injection compression molding method, extrusion molding method, blow molding method, press molding method, vacuum molding method and foam molding method. It is done.

In addition, the components other than the polycarbonate resin can be added in advance as a masterbatch by melt-kneading with the polycarbonate resin or other thermoplastic resin.
Further, it is preferably pelletized and injection molded, and special molding methods such as general injection molding method or injection compression molding method and gas assist molding method can be used, and various molded products can be produced. .

  The molded body made of the polycarbonate resin composition of the present invention can maintain excellent impact resistance at a low temperature over a long period of time even when it is repeatedly used in a high temperature and high humidity environment. Therefore, the molded article of the present invention is a product or part that is cleaned with hot water of 90 ° C. or higher and / or steam of 100 ° C. or higher, in an environment of a temperature of 60 ° C. or higher, and a relative humidity of 90% or higher. It is suitable for products or parts that are used in an environment where the low temperature environment is repeatedly reduced to below zero.

  More specific uses of the molded body of the present invention include chocolate processing molds and ice processing molds that are used after being frozen and steam washed, containers for storing frozen foods, processed seafood pools, tableware dryers, rice cookers Applications such as containers used for the like are preferred. Moreover, it is also suitable for uses such as industrial parts such as instrumentation boxes, junction boxes, underground buried members in cold regions, etc. in a high temperature and high humidity environment.

Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
In addition, the measurement methods (calculation methods) for the following physical property values and the like in this example are as follows.

(1) Measuring method of viscosity number (VN) It measured based on ISO1628-4 (1999).
(2) Measuring method of viscosity average molecular weight The intrinsic viscosity [η] of a methylene chloride solution at 20 ° C. was measured with an Ubbelohde type viscosity tube and calculated from the following relational expression (Schnell's formula).
[Η] = 1.23 × 10 ⁻⁵ × Mv ^0.83

Production Example 1
(Synthesis example of polycarbonate oligomer)
Add 2,000 mass ppm sodium dithionite to 5.6 mass% aqueous sodium hydroxide solution to bisphenol A that is dissolved later, and add bisphenol A to the bisphenol A concentration to 13.5 mass%. It melt | dissolved and the sodium hydroxide aqueous solution of bisphenol A was prepared.
At a flow rate of 40 L / hr of this sodium hydroxide aqueous solution of bisphenol A and 15 L / hr of methylene chloride, phosgene was continuously passed through a tubular reactor having an inner diameter of 6 mm and a tube length of 30 m at a flow rate of 4.0 kg / hr. The tubular reactor had a jacket portion, and the temperature of the reaction solution was kept at 40 ° C. or lower by passing cooling water through the jacket.
The reaction solution exiting the tubular reactor was continuously introduced into a 40-liter baffled tank reactor equipped with a receding blade, and further 2.8 L / hr of sodium hydroxide aqueous solution of bisphenol A, 25 The reaction was carried out by adding 0.04 L / hr of a mass% aqueous sodium hydroxide solution, 17 L / hr of water, and 0.64 L / hr of an aqueous 1 mass% triethylamine solution. The reaction liquid overflowing from the tank reactor was continuously extracted and allowed to stand to separate and remove the aqueous phase, and the methylene chloride phase was collected.
The polycarbonate oligomer thus obtained had a concentration of 318 g / L and a chloroformate group concentration of 0.75 mol / L. Moreover, the weight average molecular weight (Mw) was 1190.
In addition, the weight average molecular weight (Mw) uses THF (tetrahydrofuran) as a developing solvent, GPC [column: TOSOH TSK-GEL MULTIPIORE HXL-M (two) + Shodex KF801 (one), temperature 40 ° C., flow rate 1. It was measured as a standard polystyrene equivalent molecular weight (weight average molecular weight: Mw) at 0 ml / min, detector: RI].

Production Example 2
(Synthesis of PC-PDMS copolymer (SIPC-1))
In a 50 L tank reactor equipped with a baffle plate, a paddle type stirring blade and a cooling jacket, the polycarbonate oligomer solution 15 L produced in Production Example 1, 8.9 L methylene chloride, and the average number n of dimethylsiloxy units are 90. Charge 307 g of 2-allylphenol end-modified polydimethylsiloxane (PDMS-1) and 8.8 mL of triethylamine, add 1389 g of 6.4% by weight aqueous sodium hydroxide solution under stirring, and add polycarbonate oligomer and 2-allylphenol for 10 minutes. Reaction of terminal-modified polydimethylsiloxane was performed.
To this polymerization solution, methylene chloride solution of pt-butylphenol (PTBP) (129 g of PTBP dissolved in 2.0 L of methylene chloride), sodium hydroxide aqueous solution of bisphenol A (581 g of sodium hydroxide and sodium dithionite 2 (1147 g of bisphenol A dissolved in an aqueous solution of 3 g in 8.5 L of water) was added, and the polymerization reaction was carried out for 50 minutes. After adding 10 L of methylene chloride for dilution and stirring for 10 minutes, the organic phase was separated into an organic phase containing polycarbonate and an aqueous phase containing excess bisphenol A and sodium hydroxide, and the organic phase was isolated.
The methylene chloride solution of the polycarbonate-polydimethylsiloxane copolymer thus obtained was sequentially washed with 15% by volume of 0.03 mol / L sodium hydroxide aqueous solution and 0.2 mol / L hydrochloric acid. The washing was repeated with pure water until the electric conductivity in the aqueous phase after washing was 0.01 μS / m or less. The methylene chloride solution of the polycarbonate-polydimethylsiloxane copolymer obtained by washing was concentrated and pulverized, and the obtained flakes were dried at 120 ° C. under reduced pressure.
The polycarbonate-polydimethylsiloxane copolymer (PC-PDMS copolymer (SIPC-1)) obtained as described above has an amount of polydimethylsiloxane residue determined by NMR measurement of 6.0% by mass, The viscosity number was 46.9 and the viscosity average molecular weight was 17,400.

Production Example 3
(Synthesis of PC-PDMS copolymer (SIPC-2))
In a 50 L tank reactor equipped with baffle plates, paddle type stirring blades and a cooling jacket, the polycarbonate oligomer solution 15 L produced in Production Example 1, 8.9 L methylene chloride, and the average number of repetitions n of dimethylsiloxy units are 40. Charge 307 g of 2-allylphenol-terminated polydimethylsiloxane (PDMS-2) and 8.8 mL of triethylamine, add 1389 g of 6.4% by weight aqueous sodium hydroxide solution under stirring, and add polycarbonate oligomer and 2-allylphenol for 10 minutes. Reaction of terminal-modified polydimethylsiloxane was performed.
To this polymerization solution, methylene chloride solution of pt-butylphenol (PTBP) (129 g of PTBP dissolved in 2.0 L of methylene chloride), sodium hydroxide aqueous solution of bisphenol A (581 g of sodium hydroxide and sodium dithionite 2 (1147 g of bisphenol A dissolved in an aqueous solution of 3 g in 8.5 L of water) was added, and the polymerization reaction was carried out for 50 minutes. After adding 10 L of methylene chloride for dilution and stirring for 10 minutes, the organic phase was separated into an organic phase containing polycarbonate and an aqueous phase containing excess bisphenol A and sodium hydroxide, and the organic phase was isolated.
The methylene chloride solution of the polycarbonate-polydimethylsiloxane copolymer thus obtained was sequentially washed with 15% by volume of 0.03 mol / L sodium hydroxide aqueous solution and 0.2 mol / L hydrochloric acid. The washing was repeated with pure water until the electric conductivity in the aqueous phase after washing was 0.01 μS / m or less. The methylene chloride solution of the polycarbonate-polydimethylsiloxane copolymer obtained by washing was concentrated and pulverized, and the obtained flakes were dried at 120 ° C. under reduced pressure.
The polycarbonate-polydimethylsiloxane copolymer (PC-PDMS copolymer (SIPC-2)) obtained as described above has an amount of polydimethylsiloxane residue determined by NMR measurement of 6.2% by mass, The viscosity number was 46.9 and the viscosity average molecular weight was 17,400.

Examples 1, 2, 12, 13, 14, Reference Examples 1-11, Comparative Examples 1-12
(Preparation of pellets)
A resin composition was prepared with a blending amount (unit: parts by mass) in which the components shown in Table 1 and Table 2 were described, and a single screw extruder “NVC-50” (product name, Nakatani Machine Co., Ltd.) The heater temperature was set to 280 ° C., and the strands were extruded at 30 kg / hour, and pellets were produced with a strand cutter.

(Preparation of test plate)
After the prepared pellets were sufficiently dried, an injection molding machine “IS150E” (product name, manufactured by Toshiba Machine Co., Ltd.) was used. Using two molds, injection molding was performed at a molding temperature of 310 ° C. and a mold temperature of 80 ° C. to prepare 30 test plates each having a thickness of 2.0 mm × length 140 mm × width 140 mm.

In addition, each component described in Table 1 and Table 2 is as follows.
Component (A-1) “SIPC-1” (PC-PDMS copolymer produced in Production Example 2)
"SIPC-2" (PC-PDMS copolymer produced in Production Example 3)
Component (A-2) “Taflon FN1700A” (trade name, manufactured by Idemitsu Kosan Co., Ltd., bisphenol A polycarbonate having pt-butylphenol as a terminal group, viscosity number 46.6, viscosity average molecular weight Mv = 17,300)
"Taflon FN1900A" (trade name, manufactured by Idemitsu Kosan Co., Ltd., bisphenol A polycarbonate having pt-butylphenol as a terminal group, viscosity number 51.1, viscosity average molecular weight Mv = 19,300)
"Taflon FN2200A" (trade name, manufactured by Idemitsu Kosan Co., Ltd., bisphenol A polycarbonate having pt-butylphenol as a terminal group, viscosity number 55.6, viscosity average molecular weight Mv = 21,300)
"Taflon FN2500A" (trade name, manufactured by Idemitsu Kosan Co., Ltd., bisphenol A polycarbonate having pt-butylphenol as a terminal group, viscosity number 62.2, viscosity average molecular weight Mv = 24,200)
"Taflon FN2600A" (trade name, manufactured by Idemitsu Kosan Co., Ltd., bisphenol A polycarbonate having pt-butylphenol as a terminal group, viscosity number 64.9, viscosity average molecular weight Mv = 25,400)
"Novalex 7030PJ" (trade name, manufactured by Mitsubishi Engineering Plastics, bisphenol A polycarbonate having pt-butylphenol as a terminal group, viscosity number 73.7, viscosity average molecular weight Mv = 29,300)

Component (B) “IRGAFOS168” (trade name, manufactured by BASF, Tris (2,4-di-t-butylphenyl) phosphite)
・ "JC263" (trade name, manufactured by Johoku Chemical Co., Ltd., triphenylphosphine)
Component (C) “Celoxide 2021P” (trade name, manufactured by Daicel Corporation, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate)
・ "Sanso Sizer E-PO" (trade name, manufactured by Shin Nippon Chemical Co., Ltd., epoxyhexahydrophthalic acid diepoxy stearyl, oxirane oxygen concentration: 5.50%)
・ "Sanso Sizer E-2000H" (trade name, manufactured by Shin Nippon Chemical Co., Ltd., epoxidized soybean oil, oxirane oxygen concentration: 6.70%)
・ "Sanso Sizer E-9000H" (trade name, manufactured by Shin Nippon Chemical Co., Ltd., epoxidized linseed oil, oxirane oxygen concentration: 8.50%)
・ "Sanso Sizer E-PS" (trade name, manufactured by Shin Nippon Chemical Co., Ltd., di-2-ethylhexyl epoxyhexahydrophthalate, oxirane oxygen concentration: 3.40%)
・ "Sanso Sizer E-6000" (trade name, manufactured by Shin Nippon Chemical Co., Ltd., di-2-ethylhexyl epoxyhexahydrophthalate, oxirane oxygen concentration: 3.50%)

  The test shown below was done using the produced pellet and test plate. The test results are shown in Tables 1 and 2.

(1) Measurement item before pressure cooker test (1-1) Measurement of viscosity number (VN) and viscosity average molecular weight (Mv) Viscosity of resin composition (pellet) before pressure cooker test based on the measurement method described above Number (VN) and viscosity average molecular weight (Mv) were measured.

(1-2) Low temperature drop weight impact test The produced test plate was immersed in ethanol and cooled at -30 ° C. Then, the cooled test plate is fixed to a pedestal having a diameter of 75 mm using an automatic falling weight impact tester “HYDOSHOT” (manufactured by Shimadzu Corporation) in accordance with JIS K7211-2, and an impact of 12.7 mm in diameter. The core was abutted at a speed of 3.9 m / sec to confirm the breaking condition of the test plate. When the strike core penetrated through the test plate and the test plate was not cracked or spattered, it was considered as ductile fracture, and when it was cracked and spattered, it was regarded as brittle fracture. The test was carried out with 5 test plates, and the number of test plates that had ductile fracture in 5 was counted. At the same time, the fracture energy (J) generated upon impact was measured.

(1-3) Measurement of melt volume flow rate (MVR) It measured according to JISK7210 using the MVR measuring machine. That is, using a MVR measuring machine, the cylinder of the measuring machine was heated to 300 ° C. and aged for 15 minutes or more, and then the sample (prepared resin composition) was filled. Then, a piston and a weight are placed on the sample so that the weight is 1.2 kg, preheating is performed, the sample that has flowed out for 30 seconds is cut out, the sample that has flowed out is weighed, and the flow out per 10 minutes is measured. Converted to quantity.
(1-4) Measurement of flow value (Q value) Measured according to JIS K 7210 using an elevated flow tester, that is, with a diameter of 1 mm and a length of 10 mm under a pressure of 280 ° C. and 15.7 MPa. The amount of molten resin (mL / sec) flowing out from the nozzle was measured. The flow value (Q value) increases as the melt viscosity decreases.

(1-4) Method of pressure cooker test Two holes of 1 mm are made at the end of the test plate having a thickness of 2.0 mm × length of 140 mm × width of 140 mm, and a stainless steel net larger than the test plate is made of stainless steel. The test plate was hung with a wire. Each test plate was stopped with a clip so that the suspended test plates were not in contact with each other, and the test plates were separated from each other by 1 mm or more, and each test plate was suspended by 10 pieces. The koji was placed in four pressure cooker testers (manufactured by NAKAYAMA) each having about 5 liters of pure water at the bottom, and steamed at 121 ° C. for 300 hours in the tester. At the same time, for the molecular weight measurement, placed in a diameter 40 mm × stainless dish height 15mm same pellets 10 to 20 cm ³ brewed as used in preparation of the test plate, placed in the same pressure cooker test machine and test plate, at the same time Steamed. This operation was repeated to obtain 20 test plates for each prescription and pellets for evaluating the degree of hydrolysis of the test plates.

(2) Evaluation after pressure cooker test (pressure cooker) (2-1) Measurement of viscosity number (VN) and viscosity average molecular weight (Mv) Using pellets for evaluating the degree of hydrolysis applied to a pressure cooker tester, Based on the measurement method described above, the viscosity number (VN) and the viscosity average molecular weight (Mv) of the resin composition (pellet) are measured, the difference (ΔMv) from the viscosity average molecular weight before the test, and the decrease rate of the viscosity average molecular weight. P was calculated by the following formula.
P [%] = (M ₁ −M ₂ ) / M ₁ × 100
(M ₁ is a viscosity-average molecular weight of pressure cooker test before the resin composition (pellets), M ₂ represents the viscosity average molecular weight of the resin composition after pressure cooker test (pellets).)

(2-2) Evaluation of low-temperature drop weight impact resistance An automatic drop weight impact test was performed on the test plate placed on a pressure cooker test machine under the same conditions as described above to confirm the state of fracture. The test was carried out with 20 test plates placed on a pressure cooker tester, and the number of ductile fractured test plates in 20 was counted.

(3) Evaluation of molding process stability (residence test)
The pellets before the pressure cooker produced in the examples and comparative examples were formed into a flat plate using a 40-ton injection molding machine (product name “EC40N”, manufactured by Toshiba Machine Co., Ltd.) at a molding temperature of 360 ° C. and a mold temperature of 80 ° C. (Thickness 3.0 mm × length 40 mm × width 80 mm). For the evaluation of residence, 20 shots were molded in a 20-second cycle until the temperature condition was stabilized at a molding temperature of 360 ° C., and then the cycle was changed to 300 seconds to collect 5 shots (20 minutes). The resulting molded product was evaluated for discoloration and occurrence of silver according to the following criteria.
A: Discoloration (yellowing) of the molded body and generation of silver are not observed.
B: Discoloration (yellowing) of the molded product and generation of silver are partially observed, but not so conspicuous.
C: Discoloration (yellowing) of the molded body and generation of silver are conspicuous.

From Table 1, the resin compositions of Examples 1, 2, 12, 13, 14 and Reference Examples 1 to 11 containing specific components have a decrease rate of the viscosity average molecular weight after the pressure cooker test of 20% or less. Therefore, it has excellent impact resistance at low temperatures. Moreover, even if it stays at a high temperature for at least 15 minutes or more, the influence of discoloration or the like is small, and the processing stability is also good.
On the other hand, according to Table 2, since the resin compositions of Comparative Examples 1 to 4 do not contain the antioxidant (B), discoloration is observed when retained at a high temperature for at least about 10 minutes, and the processing stability Is inferior. In addition, the resin compositions of Comparative Examples 5 to 12 have a problem in impact resistance at low temperatures compared to the present example because the rate of decrease in the viscosity average molecular weight after the pressure cooker test exceeds 20%. became.

The polycarbonate resin composition of the present invention has good processing stability without causing discoloration or the like even if it stays at a high temperature, and the molded product made of the resin composition is repeatedly used in a high temperature and high humidity environment. However, excellent impact resistance at low temperatures can be maintained over a long period of time.
Therefore, the molded body made of the polycarbonate resin composition of the present invention is a chocolate processing mold or ice processing mold that is steam-washed after being used frozen, or a container for storing frozen food, a processed pool for seafood, a tableware dryer It is suitable for applications such as containers used in rice cookers, etc., and industrial parts such as instrumentation boxes, junction boxes, underground buried members in cold regions under high temperature and high humidity environments.

Claims (8)

As aromatic polycarbonate resin other than the aromatic polycarbonate-polyorganosiloxane copolymer (A-1) 5 to 100% by mass and the component (A-1), bisphenol A polycarbonate (A-2) 95 to 0% by mass Yes, with respect to 100 parts by mass of the aromatic polycarbonate resin mixture (A) having a polyorganosiloxane unit content of 1% by mass or more, including 0.002 to 0.200 parts by mass of the phosphorus-based antioxidant (B) The polycarbonate resin composition does not substantially contain the epoxidation stabilizer (C), and the reduction rate P of the viscosity average molecular weight of the polycarbonate resin composition calculated from the following calculation formula (I) is 20% or less. Polycarbonate resin composition.
Calculation formula (I): P [%] = (M ₁ −M ₂ ) / M ₁ × 100
(In the above formula (I), M ₁ is the viscosity average molecular weight of the resin composition measured after making the polycarbonate resin composition into pellets, and M ₂ is a pressure cooker in which the pellets are set at 121 ° C. It represents the viscosity average molecular weight of the resin composition after the pressure cooker test, measured after being put into a testing machine for 300 hours, and P is the viscosity average molecular weight of the resin composition before the pressure cooker test. It represents the rate of decrease in viscosity average molecular weight of the resin composition after the test.) The viscosity-average molecular weight of formula (I) wherein the resin composition after the pressure cooker test, represented by M ₂ in is 16000 or more, the polycarbonate resin composition of claim 1.   The polycarbonate resin composition according to claim 1 or 2, wherein the phosphorus antioxidant (B) is a phosphite antioxidant or a phosphine antioxidant.   The phosphorus-based antioxidant (B) is a phosphite-based antioxidant, and the content of the component (B) is 0.002 to 0.020 parts by mass with respect to 100 parts by mass of the component (A). Item 4. The polycarbonate resin composition according to any one of Items 1 to 3.   The polycarbonate resin composition in any one of Claims 1-3 whose phosphorus antioxidant (B) is a phosphine antioxidant.   The molded article which consists of a polycarbonate resin composition in any one of Claims 1-5.   The molded article according to claim 6, wherein the molded article is a product or a part that is cleaned with warm water of 90 ° C or higher and / or steam of 100 ° C or higher.   The molded article according to claim 6 or 7, wherein the molded article is a product or a part used in an environment having a temperature of 60 ° C or higher and a relative humidity of 90% or higher.