WO2017057092A1 - Polycarbonate resin composition and method for producing same - Google Patents

Abstract

Provided are: a polycarbonate resin composition which has excellent mechanical properties and wet heat resistance, while being free from the problem of mold contamination due to mold deposit; and a production method which is capable of producing this polycarbonate resin composition with high productivity. A polycarbonate resin composition which contains 60-95% by mass of a polycarbonate resin (A) and 40-5% by mass of an emulsion polymerized styrene resin (B) based on 100% by mass of the total of the components (A) and (B), and which is characterized in that: the emulsion polymerized styrene resin (B) is a graft copolymer that is obtained from a styrene monomer-vinyl cyanide monomer and/or an alkyl (meth)acrylate monomer-rubbery polymer; and the total amount of gas in cases where the resin composition is heated at 280°C for 10 minutes is 3,000 ppm or less in terms of the mass of decane.

Description

Polycarbonate resin composition and method for producing the same

The present invention relates to a polycarbonate resin composition and a method for producing the same, and more particularly, a polycarbonate resin composition having excellent mechanical properties and moisture and heat resistance and no mold contamination due to mold deposits, and a method for producing the polycarbonate resin composition with high production efficiency. About.

Polycarbonate resin is a resin excellent in heat resistance, mechanical properties, and electrical characteristics, and is widely used for, for example, automobile materials, electrical and electronic equipment materials, housing materials, and other parts manufacturing materials in industrial fields. In addition, many polymer alloys with other thermoplastic resins have been developed. Above all, polymer alloys with styrenic resins represented by ABS resins are more cost-effective and have higher moldability and impact resistance than polycarbonate resins. It has been improved and is widely used as a part of various electronic devices such as various computers, personal computers, various portable terminals, printers, copying machines, and OA information devices.

As the ABS resin used for the polycarbonate / styrene resin composition, those manufactured by emulsion polymerization are often used from the viewpoints of cost, compatibility with various varieties, and easy quality improvement due to high rubber. On the other hand, as described in Patent Document 1, a product produced by bulk polymerization is sometimes used because of its excellent heat and humidity resistance (the same document, claim 8 and paragraph [0024]). ].
Styrenic resin by bulk polymerization is expensive, and it is conceivable to use an emulsion polymerization product for cost reduction, but the polycarbonate resin composition containing the emulsion polymerization styrene resin is surely inferior in heat and moisture resistance. Has drawbacks. Furthermore, there is a problem that mold contamination due to mold deposits is significant and the amount of gas generated is large during molding.
Such a problem is considered to be caused by the component derived from the emulsifier used in the emulsion polymerization or the oligomer component remaining in the styrene resin. The mechanism is not sufficiently elucidated, but the component derived from the emulsifier is a polycarbonate resin. It is considered that the oligomer component causes mold contamination and gas generation.

Emulsion polymerization ABS resin usually uses higher fatty acid soap or rosin acid soap as an emulsifier, and performs emulsion polymerization of butadiene with a water-soluble polymerization initiator to obtain a polymer latex, and then the polymer particles and the emulsifier In the presence of water, styrene and acrylonitrile are polymerized to obtain an ABS polymer latex, to which a coagulant such as an inorganic acid or a divalent metal salt is added to separate the polymer, which is washed and dried. Manufactured. From the viewpoint of economy, the emulsifier that has not been completely removed remains in the product because the emulsifier is not completely removed in the washing step.
Although it is conceivable that the emulsion polymerization ABS resin raw material to be used is thoroughly washed in advance, the emulsifier component incorporated into the resin cannot be easily removed even after thorough washing with an organic solvent such as water or methanol. found.

JP 2001-64502 A

The present invention has an object (problem) to provide a polycarbonate resin composition containing an emulsion-polymerized styrene resin, in which the problems of heat and moisture resistance and mold deposit are solved, and a method for producing the same with high production efficiency.

As a result of intensive studies to achieve the above-mentioned problems, the inventor is a resin composition containing a specific amount of a polycarbonate resin and a specific emulsion-polymerized styrene resin, and the resin composition is 280 ° C., 10 ° C. Polycarbonate / styrene resin composition whose total gas amount when heated for a minute is 3000 mass ppm or less in terms of decane mass is excellent in mechanical properties and heat and humidity resistance, and there is no problem of mold contamination due to mold deposit I found.
In addition, when producing a polycarbonate resin composition by melt-kneading an emulsion-polymerized styrene resin and a polycarbonate resin, an emulsion-polymerized styrene-based resin, which is an additive component and a small amount component compared to the polycarbonate resin, is first added to the root of the extruder. The above problem is solved by venting under reduced pressure to devolatilize the gas generating component derived from the emulsifier, and supplying the polycarbonate resin as the main component from the raw material supply port downstream from the vent port and melt-kneading. In addition, by injecting water during the melt-kneading of the styrene-based resin, it was found that the above-mentioned problems can be further solved and the production can be performed with high productivity, and the present invention has been achieved.
This invention is the manufacturing method of the following polycarbonate resin compositions, its molded article, and the following polycarbonate resin compositions.

[1] A resin composition comprising 60 to 95% by weight of a polycarbonate resin (A) and 40 to 5% by weight of an emulsion-polymerized styrene-based resin (B) based on a total of 100% by weight of (A) and (B). ,
The emulsion polymerization styrene resin (B) is a graft copolymer comprising a styrene monomer-vinyl cyanide monomer and / or an alkyl (meth) acrylate monomer-rubber polymer,
A polycarbonate resin composition, wherein the total gas amount when the resin composition is heated at 280 ° C. for 10 minutes is 3000 ppm by mass or less in terms of decane mass.
[2] The styrene resin (B) is dispersed in an island shape in the matrix of the polycarbonate resin (A), the volume average dispersion diameter (dv) is 2.5 μm or less, and the styrene resin (B The ratio of the volume average particle diameter (dv) to the number average particle diameter (dn) (dv / dn) is in the range of 1.0 to 1.5.
[3] The polycarbonate resin composition according to the above [1] or [2], wherein the impact strength retention after heat-moisture treatment for 400 hours in an environment of a temperature of 90 ° C and a relative humidity of 95% is 50% or more.

[4] Based on a total of 100 mass% of (A) to (C), polycarbonate resin (A) 60 to 95 mass%, emulsion polymerized styrene resin (B) 40 to 5 mass%, other than emulsion polymerized styrene resin A resin composition containing 0 to 30% by mass of another styrenic resin (C),
The emulsion polymerization styrene resin (B) is a graft copolymer comprising a styrene monomer-vinyl cyanide monomer and / or an alkyl (meth) acrylate monomer-rubber polymer,
A polycarbonate resin composition, wherein the total gas amount when the resin composition is heated at 280 ° C. for 10 minutes is 3000 ppm by mass or less in terms of decane mass.
[5] The polycarbonate resin composition according to the above [4], wherein the other styrene resin (C) is a suspension polymerization or a block polymerization styrene resin.
[6] The polycarbonate resin composition according to the above [4] or [5], wherein the other styrenic resin (C) is a suspension polymerization AS resin.
[7] The polycarbonate resin composition according to any one of the above [4] to [6], wherein the other styrenic resin (C) is a block polymerization ABS resin.
[8] The emulsion-polymerized styrene resin (B) is dispersed in islands in the matrix of the polycarbonate resin (A), the volume average dispersion diameter (dv) is 2.5 μm or less, and the emulsion-polymerized styrene The ratio of the volume average particle diameter (dv) to the number average particle diameter (dn) (dv / dn) of the resin (B) is in the range of 1.0 to 1.5. The polycarbonate resin composition in any one.
[9] The polycarbonate resin composition according to any one of the above [1] to [8], which has an impact strength retention rate of 50% or more after wet heat treatment in an environment of 90 ° C. and 95% relative humidity for 400 hours .
[10] A molded article of the polycarbonate resin composition according to any one of [1] to [9].

[11] A polycarbonate resin composition containing 60 to 95% by weight of polycarbonate resin (A) and 40 to 5% by weight of emulsion-polymerized styrene resin (B) based on a total of 100% by weight of (A) and (B) is vented. It is a method of manufacturing by melt-kneading with a twin screw extruder,
The extruder has a first raw material supply port on the upstream side and one or more second raw material supply ports on the downstream side thereof,
The supply amount of the emulsion polymerization styrene resin (B) is B (1), the supply amount of the polycarbonate resin (A) from the first raw material supply port is A (1), and the second raw material supply of the polycarbonate resin (A). When the supply amount from the mouth is A (2), the sum of A (1) and A (2) is the total supply amount of the polycarbonate resin (A),
From the first raw material supply port, styrene resin (B) and polycarbonate resin (A),
Formula: B (1)> A (1) (However, A (1) includes 0.)
Supply to meet and
After melt-kneading, after degassing the gas component from the vent port under reduced pressure,
A method for producing a polycarbonate resin composition, comprising: supplying a polycarbonate resin (A) in an amount of A (2) from a second raw material supply port downstream of the vent port.
[12]
The method for producing a polycarbonate resin composition according to [11], wherein the gas component includes a gas component derived from an emulsifier.

[13]
A polycarbonate resin composition containing 60 to 95% by weight of a polycarbonate resin (A) and 40 to 5% by weight of an emulsion-polymerized styrene resin (B) based on a total of 100% by weight of (A) and (B). A method of manufacturing by melt-kneading with an extruder,
The extruder has a first raw material supply port on the upstream side and a water injection part and a vent port in the kneading part on the downstream side, and further has one or more second raw material supply ports on the downstream side. And
The supply amount of the emulsion polymerization styrene resin (B) is B (1), the supply amount of the polycarbonate resin (A) from the first raw material supply port is A (1), and the second raw material supply of the polycarbonate resin (A). When the supply amount from the mouth is A (2), the sum of A (1) and A (2) is the total supply amount of the polycarbonate resin (A),
From the first raw material supply port, styrene resin (B) and polycarbonate resin (A),
Formula: B (1)> A (1) (However, A (1) includes 0.)
Supply to meet and
Then, after injecting water from the water injection part provided in the kneading part and melt-kneading, after degassing the gas component from the vent port,
A method for producing a polycarbonate resin composition, characterized in that the polycarbonate resin (A) is supplied in an amount of A (2) from a second raw material supply port downstream of the vent port.
[14]
The method for producing a polycarbonate resin composition according to the above [13], wherein the gas component contains a gas component derived from an emulsifier.
[15]
The polycarbonate resin composition according to the above [13] or [14], wherein the vent type twin screw extruder is an extruder having a water injection part and a vent port in multiple stages, and performs water injection and vacuum devolatilization in multiple stages. Production method.
[16]
A molded article obtained by molding the polycarbonate resin composition obtained by the production method of [11] to [15] above.

The polycarbonate resin composition of the present invention is excellent in mechanical properties and moisture and heat resistance, and has no problem of mold contamination due to mold deposit. In addition, the method for producing a polycarbonate resin composition of the present invention can produce a polycarbonate resin composition having excellent mechanical properties and heat-and-moisture resistance and no problem of mold contamination due to mold deposits with high productivity.

2 is a SEM photograph (magnification 1500 times) of a core part of a molded product obtained in Example 1. FIG. 2 is a SEM photograph (magnification 3000 times) of a core part of a molded product obtained in Example 1. FIG. 3 is a SEM photograph (magnification 1500 times) of a core part of a molded product obtained in Comparative Example 1. 2 is a SEM photograph (magnification 3000 times) of a core part of a molded product obtained in Comparative Example 1. It is a top view of the drop mold used for evaluation of mold contamination.

Hereinafter, although an embodiment, an example thing, etc. are shown and explained in detail about the present invention, the present invention is limited to an embodiment, an example, etc. shown below and is not interpreted.
In the present specification, “˜” is used to mean that the numerical values described before and after it are used as the lower limit and the upper limit unless otherwise specified. “Ppm” means mass ppm unless otherwise specified.

The polycarbonate resin composition of the present invention contains 60 to 95% by weight of the polycarbonate resin (A) and 40 to 5% by weight of the emulsion polymerization styrene resin (B) based on a total of 100% by weight of (A) and (B). A resin composition comprising:
The emulsion polymerization styrene resin (B) is a graft copolymer comprising a styrene monomer-vinyl cyanide monomer and / or an alkyl (meth) acrylate monomer-rubber polymer,
The total gas amount when the resin composition is heated at 280 ° C. for 10 minutes is 3000 mass ppm or less in terms of decane mass.

The production method of the polycarbonate resin composition of the present invention is based on a total of 100% by mass of (A) and (B), 60 to 95% by mass of the polycarbonate resin (A), and 40 to 5% by mass of the emulsion-polymerized styrene resin (B). A polycarbonate resin composition containing 2% by melt-kneading with a vented twin screw extruder,
The extruder has a first raw material supply port on the upstream side and one or more second raw material supply ports on the downstream side thereof,
The supply amount of the emulsion polymerization styrene resin (B) is B (1), the supply amount of the polycarbonate resin (A) from the first raw material supply port is A (1), and the second raw material supply of the polycarbonate resin (A). When the supply amount from the mouth is A (2), the sum of A (1) and A (2) is the total supply amount of the polycarbonate resin (A),
From the first raw material supply port, styrene resin (B) and polycarbonate resin (A),
Formula: B (1)> A (1) (However, A (1) includes 0.)
Supply to meet and
After melt-kneading, after degassing the gas component from the vent port under reduced pressure,
The polycarbonate resin (A) is supplied in an amount of A (2) from the second raw material supply port downstream from the vent port.
Furthermore, in the production method of the present invention, it is preferable to perform water injection in the above.

[Polycarbonate resin (A)]
Examples of the polycarbonate resin (A) used in the present invention include aromatic polycarbonate resins, aliphatic polycarbonate resins, and aromatic-aliphatic polycarbonate resins. Preferred are aromatic polycarbonate resins. Specifically, A thermoplastic aromatic polycarbonate polymer or copolymer obtained by reacting an aromatic dihydroxy compound with phosgene or a diester of carbonic acid is used.

Aromatic dihydroxy compounds include 2,2-bis (4-hydroxyphenyl) propane (ie, bisphenol A), tetramethylbisphenol A, α, α'-bis (4-hydroxyphenyl) -p-diisopropylbenzene, hydroquinone , Resorcinol, 4,4′-dihydroxydiphenyl, and the like. Further, in order to improve flame retardancy, a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the aromatic dihydroxy compound described above, a polymer having both ends phenolic OH groups having a siloxane structure, or an oligomer thereof is used. Also good.

Preferable examples of the polycarbonate resin (A) include 2,2-bis (4-hydroxyphenyl) propane as a dihydroxy compound, that is, a polycarbonate resin in which bisphenol A or a combination of bisphenol A and another aromatic dihydroxy compound is used. .

The polycarbonate resin may be a homopolymer composed of one type of repeating unit or a copolymer having two or more types of repeating units. At this time, the copolymer can be selected from various copolymerization forms such as a random copolymer and a block copolymer.

The molecular weight of the polycarbonate resin (A) is not limited, but is preferably from 10,000 to 40,000, more preferably from 14,000 to 32,000 in terms of viscosity average molecular weight (Mv). When the viscosity average molecular weight is within this range, the resulting resin composition has good moldability and a molded product having high mechanical strength is easily obtained. The most preferred viscosity average molecular weight range of the polycarbonate resin (A) is 16,000 to 30,000.

In the present invention, the viscosity average molecular weight (Mv) of the polycarbonate resin (A) is determined by measuring the viscosity of the methylene chloride solution of the polycarbonate resin at 20 ° C. using an Ubbelohde viscometer. Is a value calculated from the following Schnell viscosity equation.
[Η] = 1.23 × 10 ⁻⁴ Mv ^0.83

The method for producing the polycarbonate resin (A) is not particularly limited, and a polycarbonate resin produced by any of the phosgene method (interfacial polymerization method) and the melting method (transesterification method) can also be used. Moreover, the polycarbonate resin which performed the post-process which adjusts the amount of terminal OH groups to the polycarbonate resin manufactured by the melting method is also preferable.

The polycarbonate resin (A) may contain a polycarbonate oligomer. The viscosity average molecular weight [Mv] of this polycarbonate oligomer is usually 1,500 or more, preferably 2,000 or more, and usually 9,500 or less, preferably 9,000 or less. Furthermore, the polycarbonate ligomer contained is preferably 30% by mass or less of the polycarbonate resin (including the polycarbonate oligomer).

Also, the polycarbonate resin (A) is not limited to virgin raw materials, but it is also possible to use aromatic polycarbonate resin recycled from used products, so-called material recycled aromatic polycarbonate resin. Used products include optical recording media such as optical disks, light guide plates, automotive window glass and automotive headlamp lenses, vehicle transparent members such as windshields, containers such as water bottles, glasses lenses, soundproof walls and glass windows, corrugated plates Preferred examples include building members such as In addition, as the recycled polycarbonate resin, non-conforming product, pulverized product obtained from sprue or runner, or pellets obtained by melting them can be used.

[Emulsion polymerization styrene resin (B)]
The emulsion polymerization styrene resin (B) used in the present invention uses an emulsion polymer product produced by emulsion polymerization using an emulsifier.
The content of the emulsion polymerization styrene resin (B) is 40 to 5% by mass based on the total of 100% by mass of (A) and (B), and the polycarbonate resin (A) is 60 to 95% as the main component. % By mass. If the amount of the styrene-based resin (B) is less than 5% by mass, the fluidity at the time of molding is insufficient, and the moldability is lowered. If the content of the styrenic resin body (B) exceeds 40% by mass, the mechanical strength and heat resistance will be inferior. The amount of the styrenic resin (B) is preferably 35% by mass or less, preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more.

The emulsion polymerization styrene resin (B) includes an emulsion polymerization graft copolymer comprising a styrene monomer-vinyl cyanide monomer and / or an alkyl (meth) acrylate monomer-rubber polymer. used.

Styrene monomers include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, and monobromostyrene. , Styrene derivatives such as dibromostyrene, fluorostyrene, tribromostyrene and the like, and styrene is particularly preferable. These may be used alone or in combination of two or more.

Preferred examples of other vinyl monomers copolymerizable with these styrene monomers include vinyl cyanide monomers and / or alkyl (meth) acrylate monomers.
In the present specification, “(meth) acrylate” refers to one or both of “acrylate” and “methacrylate”. The same applies to “(meth) acryl” and “(meth) acrylo”.

Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, ethacrylonitrile and the like, and acrylonitrile is most preferably used. These can be used alone or in combination of two or more.

Alkyl (meth) acrylate monomers include alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, cyclohexyl acrylate, and dodecyl acrylate. ;
Methacrylic acid aryl esters such as phenyl methacrylate and benzyl methacrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, cyclohexyl methacrylate, and dodecyl methacrylate;
An epoxy group-containing methacrylic acid ester such as glycidyl methacrylate; and an aryl ester of acrylic acid such as phenyl acrylate and benzyl acrylate.
These can be used alone or in combination of two or more.
Among these, acrylic acid alkyl ester and methacrylic acid alkyl ester are preferable.

Other copolymerizable vinyl monomers other than the above include maleimide monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide; acrylic acid, methacrylic acid, (meth) acrylic Examples include α, β-unsaturated carboxylic acids such as glycidyl acid, glycidyl itaconate, maleic acid, maleic anhydride, phthalic acid and itaconic acid, and anhydrides thereof.
These vinyl monomers may be used alone or in a combination of two or more.

As the rubbery polymer copolymerizable with the styrene monomer, a rubber having a glass transition temperature of 10 ° C. or lower is suitable. Specific examples of such a rubbery polymer include diene rubber, acrylic rubber, ethylene / propylene rubber, silicon rubber and the like, and preferably, diene rubber and acrylic rubber.

Examples of the diene rubber include butadiene such as polybutadiene, styrene-butadiene random copolymer and block copolymer, acrylonitrile-butadiene copolymer, butyl acrylate-butadiene copolymer, and butadiene-methyl methacrylate copolymer. -(Meth) acrylic acid lower alkyl ester copolymer, polyisoprene, ethylene-isoprene copolymer, butadiene-isoprene copolymer, ethylene-propylene-butadiene copolymer, ethylene-propylene-hexadiene copolymer, etc. Examples thereof include ethylene, propylene, non-conjugated diene terpolymers, and lower alkyl ester copolymers of butadiene-styrene- (meth) acrylic acid.

Examples of the acrylic rubber include acrylic acid alkyl ester rubber, and the alkyl group preferably has 1 to 8 carbon atoms. Specific examples of the alkyl acrylate include ethyl acrylate, butyl acrylate, ethyl hexyl acrylate, and the like. An ethylenically unsaturated monomer may optionally be used in the acrylic acid alkyl ester rubber. Specific examples of such compounds include di (meth) acrylate, divinylbenzene, trivinylbenzene, triallyl cyanurate, allyl (meth) acrylate, butadiene, isoprene and the like. Examples of the acrylic rubber include a core-shell type polymer having a crosslinked diene rubber as a core.

Preferable specific examples of the emulsion polymerization styrene resin (B) include acrylonitrile-butadiene-styrene copolymer (ABS resin), methyl methacrylate-butadiene rubber-styrene copolymer (MBS resin), and methyl methacrylate by emulsion polymerization. Acrylonitrile-butadiene-styrene copolymer (MABS resin), methyl methacrylate-butadiene rubber copolymer (MB resin), acrylonitrile-acrylic rubber-styrene copolymer (AAS resin), acrylonitrile- (ethylene / propylene / diene rubber)- Styrene copolymer (AES resin), acrylonitrile-butadiene-styrene-α-methylstyrene copolymer, acrylonitrile-butadiene-styrene-N-phenylmaleimide copolymer, and the like. Acrylonitrile-butadiene-styrene copolymer (ABS resin), methyl methacrylate-butadiene rubber-styrene copolymer (MBS resin), and methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS resin) have improved moisture and heat resistance. In view of the effect of reducing mold contamination, ABS resin is particularly preferable.
In addition, a styrenic resin (B) can also be used individually or in mixture of 2 or more types.

In the present invention, the styrene resin (B) uses an emulsion polymer product produced by emulsion polymerization, but the method for producing the emulsion polymerized styrene resin (B) is well known. Alternatively, a commercially available emulsion polymerization product may be used.

As a method for producing an emulsion-polymerized styrene resin (B) by emulsion polymerization, an ABS resin will be described as an example. A general method thereof is as follows.
As the emulsifier, usually, a rosin acid soap which is a salt of abietic acid or a higher fatty acid soap which is a salt of a saturated or unsaturated fatty acid having 12 to 32 carbon atoms is used, and the diene monomer is potassium peroxodisulfate. Emulsion polymerization is carried out using a water-soluble polymerization initiator such as α-cumyl hydroperoxide to obtain a polymer latex. Next, a polymer latex is obtained by polymerizing the polymer particles, the aromatic vinyl monomer and the vinyl cyanide monomer in the presence of a further emulsifier, and an inorganic acid, a divalent metal salt, etc. The ABS coagulant is added to separate the ABS resin, washed and dried.

As described above, since the emulsifier is not completely removed in the washing process until economic efficiency is ignored, the above-described emulsifier or a component derived therefrom remains in the emulsion polymerization ABS resin, and abietic acid and / or Alternatively, higher fatty acids or salts thereof are contained in the emulsion polymerized product, and the component derived from such an emulsifier affects the hydrolysis of the polycarbonate resin and lowers the heat and moisture resistance. Oligomer remains, and it is considered that this oligomer component generates gas during molding and becomes mold deposit and causes mold contamination.
The higher fatty acid is preferably a saturated or unsaturated fatty acid having 12 to 32 carbon atoms, and typical examples thereof include oleic acid, stearic acid, palmitic acid, myristic acid and the like. Metal salts, particularly sodium salts, potassium salts, ammonium salts and the like are preferred.
Abietic acid and / or higher fatty acid or a salt thereof will be present as a gas generating component in the resin composition obtained as it is, and gas will be generated at the time of molding, resulting in mold deposits and mold contamination. It affects the hydrolysis of the polycarbonate resin and lowers the heat and moisture resistance.

In addition, oligomers remain in the emulsion-polymerized styrene resin, and the oligomer component is considered to cause mold contamination and gas generation. Although it does not restrict | limit especially as an oligomer, The monomer for comprising above-mentioned styrene resin (B), for example, a styrene monomer, a vinyl cyanide monomer, alkyl (meth) Examples include oligomers such as acrylate monomers.

As described above, the polycarbonate resin composition of the present invention contains 40 to 5% by mass of the emulsion-polymerized styrene resin (B), and the total gas amount when the resin composition is heated at 280 ° C. for 10 minutes. It is 3000 mass ppm or less in terms of decane mass. When the total gas amount is 3000 mass ppm or less, the polycarbonate resin composition of the present invention is excellent in mechanical properties and wet heat resistance, and can solve the problem of mold contamination due to mold deposits. The total gas amount is preferably 2700 mass ppm or less, more preferably 2500 mass ppm or less, and its preferred lower limit is 500 mass ppm. If it is less than 500 ppm by mass, the releasability at the time of molding is extremely deteriorated, and the appearance of the molded product, particularly the surface glossiness, is liable to be impaired.

Of these, the amount of gas derived from the emulsifier can be 380 mass ppm or less in terms of decane mass. By setting it to 380 mass ppm or less, the heat-and-moisture resistance can be made extremely good.
The gas generating component derived from the emulsifier here refers to an emulsifier component used in the emulsion polymerization of the styrene resin (B). As described above, generally, higher fatty acid soap or rosin acid is used. It is a component derived from soap, and more specifically, is abietic acid and a saturated or unsaturated fatty acid having 12 to 32 carbon atoms or a metal salt thereof. The amount of gas generated from the emulsifier is specifically the total gas amount of abietic acid and saturated or unsaturated fatty acid having 12 to 32 carbon atoms as the generated gas when the resin composition is heated at 280 ° C. for 10 minutes. In terms of decane mass, it is preferably 380 mass ppm or less, and the heat and humidity resistance is extremely good by making the total gas amount of abietic acid and saturated or unsaturated fatty acids having 12 to 32 carbon atoms be 380 mass ppm or less. can do. Preferably it is 300 mass ppm or less, More preferably, it is 200 mass ppm or less, Furthermore, it is preferable that it is 100 mass ppm or less. The preferable lower limit is 50 mass ppm in view of the releasability during molding and the appearance of the molded product.

The generated gas also contains those derived from the oligomer component remaining in the styrene resins (B) and (C). As described above, this oligomer component is a problem of mold contamination due to mold deposits and the like. Cause. Therefore, it is particularly preferable that the total gas amount when heated at 280 ° C. for 10 minutes is 3000 ppm by mass or less in terms of decane mass from the viewpoint of mold contamination and wet heat resistance.

The polycarbonate resin composition of the present invention may further contain a styrene resin (C) other than the emulsion polymerization styrene resin (B). Specifically, polycarbonate resin (A) 60 to 95% by mass, emulsion polymerized styrene resin (B) 40 to 5% by mass, based on 100% by mass total of (A) to (C), other than emulsion polymerized styrene resin Other styrenic resin (C) is contained in an amount of 0 to 30% by mass.

As the styrene resin (C) other than the emulsion polymerization styrene resin (B), suspension polymerization or block polymerization styrene resin is preferable, and suspension polymerization AS resin or block polymerization ABS resin is particularly preferable.
The suspension polymerization AS resin is a copolymer obtained by suspension polymerization of acrylonitrile and styrene, and may contain other components. Of the monomers constituting the AS resin, acrylonitrile preferably occupies 10 to 50 mol%, more preferably 15 to 40 mol%. Of the monomers constituting the AS resin, styrene preferably accounts for 50 to 90 mol%, and more preferably 60 to 85 mol%.

The ABS resin is a resin obtained by copolymerizing a rubbery polymer copolymerizable with a styrene monomer and a vinyl cyanide monomer, and preferably 40 to 80% by mass of a styrene monomer component, cyanide. It comprises 10 to 30% by mass of vinyl fluoride monomer component, 10 to 30% by mass of diene rubber polymer component, and 0 to 30% by mass of other copolymerizable vinyl monomer components.
As these styrene monomers, vinyl cyanide monomers, diene rubber polymers, and other copolymerizable vinyl monomers, those described in the emulsion polymerization styrene resin (B) The same can be used in the same way.

As the ABS resin as the styrene-based resin (C), a block polymerization ABS resin produced by block polymerization is used. The bulk polymerization method is well known, and a known method may be applied. Examples thereof include a continuous bulk polymerization method. Regarding the polymerization method, polymerization may be performed in one stage or in multiple stages.

The polycarbonate resin composition of the present invention is preferably produced by the above-described method for producing a polycarbonate resin composition of the present invention.
In the production method of the polycarbonate resin composition of the present invention, preferably, the emulsion polymerization styrene resin (B), which is a small component, is first melt-kneaded and then the polycarbonate resin (B), which is the main component, is side-feeded. Is done. By adopting such a method, a polycarbonate resin composition having excellent mechanical properties and heat-and-moisture resistance and no problem of mold contamination due to mold deposit can be produced very efficiently with high productivity.
That is, a polycarbonate resin composition containing 60 to 95% by weight of a polycarbonate resin (A) and 40 to 5% by weight of an emulsion-polymerized styrene resin (B) based on the total of 100% by weight of (A) and (B) is vented. It is a method of manufacturing by melt-kneading with a twin screw extruder,
The extruder has a first raw material supply port on the upstream side and one or more second raw material supply ports on the downstream side thereof,
The supply amount of the styrene resin (B) is B (1), the supply amount of the polycarbonate resin (A) from the first raw material supply port is A (1), and from the second raw material supply port of the polycarbonate resin (A) The total amount of A (1) and A (2) is the total amount of polycarbonate resin (A)
From the first raw material supply port, styrene resin (B) and polycarbonate resin (A),
Supply so as to satisfy the formula: B (1)> A (1) (where A (1) includes 0),
After melt-kneading, after degassing the gas component from the vent port under reduced pressure,
Manufactured by a method in which the polycarbonate resin (A) is supplied in an amount of A (2) from the second raw material supply port downstream of the vent port.

In order to further enhance the effect of reducing the amount of generated gas, it is preferable to inject water when the emulsion-polymerized styrene resin (B) is melt-kneaded.
That is, a polycarbonate resin composition containing 60 to 95% by weight of a polycarbonate resin (A) and 40 to 5% by weight of an emulsion-polymerized styrene resin (B) based on the total of 100% by weight of (A) and (B) is vented. It is a method of manufacturing by melt-kneading with a twin screw extruder,
The extruder has a first raw material supply port on the upstream side and a water injection part and a vent port in the kneading part on the downstream side, and further has one or more second raw material supply ports on the downstream side. And
The supply amount of the styrene resin (B) is B (1), the supply amount of the polycarbonate resin (A) from the first raw material supply port is A (1), and from the second raw material supply port of the polycarbonate resin (A) The total amount of A (1) and A (2) is the total amount of polycarbonate resin (A)
From the first raw material supply port, styrene resin (B) and polycarbonate resin (A),
Supply so as to satisfy the formula: B (1)> A (1) (where A (1) includes 0),
Then, after injecting water from the water injection part provided in the kneading part and melt-kneading, after degassing the gas component from the vent port,
Manufactured by a method in which the polycarbonate resin (A) is supplied in an amount of A (2) from the second raw material supply port downstream of the vent port.

As an extruder having a vacuum vent port used in the method for producing a polycarbonate resin composition of the present invention, a vent type twin screw extruder is used, and both screw rotations can be used in the same direction and in different directions. A co-rotating twin-screw extruder is suitable for efficiently removing the gas generating components in the system resin (B).

The extruder has a first raw material supply port at the root of the uppermost stream and a vent port downstream thereof. The emulsion polymerization styrene resin (B) is supplied from the first raw material supply port. The emulsion-polymerized styrene resin (B) is heated and melted in the extruder, and then becomes a decompression expansion region connected to the vent port. By connecting the vent port to a vacuum pump and venting under reduced pressure, the emulsion-polymerization styrene resin (B) Can be devolatilized under reduced pressure. The position where the vent port is installed may be a melting portion of the emulsion polymerization styrene resin (B). Two or more vent ports may be provided as desired.

It is also preferable to supply a part of the polycarbonate resin (A) to the first raw material supply port, but the supply amount of the polycarbonate resin (A) at that time is as described above.
It is preferable that the formula: B (1)> A (1) is satisfied, that is, less than the supply amount of the emulsion polymerization styrene resin (B). When the supply amount (A1) of the polycarbonate resin (A) at the first supply port is equal to or greater than the supply amount (B1) of the emulsion polymerization styrene resin (B), it is derived from the emulsifier in the emulsion polymerization styrene resin (B). The devolatilization of gas generating components becomes worse. The reason for this is not clear, but when the polycarbonate resin (A) is rich, the emulsion-polymerized styrene resin (B) is surrounded by the polycarbonate resin (A). It is considered that the devolatilization of the emulsifier component from the inside does not progress.

Next, the polycarbonate resin (A) is supplied at a supply amount of (A2) from the second raw material supply port located downstream. (A2) is the remaining amount obtained by subtracting (A1) from the total supply amount of the polycarbonate resin (A). When only the emulsion polymerization styrene resin (B) is supplied from the first supply port, that is, (A1) = In the case of 0, (A2) is the total supply amount of the polycarbonate resin (A). The polycarbonate resin (A) supplied from the second raw material supply port merges with the molten resin from the upstream, and is further melt-kneaded.
According to such a method for producing a polycarbonate resin composition of the present invention, the polycarbonate resin composition of the present invention is produced by side-feeding the polycarbonate resin (A) as the main component in the polycarbonate resin composition of the present invention. It can be manufactured with good efficiency and very efficiently.

As described above, the polycarbonate resin composition of the present invention preferably contains another styrene resin (C) other than the emulsion polymerization styrene resin. When supplying another styrene resin (C), it can be supplied from either the first supply port or the second supply port. In the case of the above-mentioned suspension polymerization AS resin or bulk polymerization ABS resin, since it does not contain an emulsifier, it may be supplied from the second supply port, but it is preferable to supply from the first supply port in consideration of the residual oligomer.

In order to further enhance the effects of the present invention, it is preferable to inject water during the melt-kneading of the emulsion polymerization styrene resin (B).
In this case, the extruder is provided with a first raw material supply port at the most upstream root, an inlet for injecting water downstream thereof, and a vent port further downstream. The emulsion-polymerized styrene resin (B) is supplied from the first raw material supply port, and after the styrene resin (B) is heated and melted in the extruder, water is pumped from the water injection port provided in the resin-filled area. It is poured and kneaded. The injected water is dispersed in the styrene resin (B). In this water injection dispersion region, it is preferable to provide a seal ring downstream to increase the pressure.
When passing through the seal ring, it becomes a reduced pressure expansion region connected to the vent port, and the water dispersed in the styrene resin (B) is foamed under reduced pressure. By connecting a vacuum pump to the vent port and venting under reduced pressure, the styrene resin (B) is foamed under reduced pressure, increasing the surface area to diffuse, and lowering the partial pressure of volatile components, thereby reducing the equilibrium concentration, Volatilization can be further promoted. The position where the vent port is installed may be a melting part of the styrene resin (B). Two or more vent ports may be provided as desired.
The vacuum degree of the decompression vent is preferably 50 mmHg or less, more preferably 20 mmHg or less, and further preferably 10 mmHg or less.

The vent type twin screw extruder preferably has a water injection part and a vent port in multiple stages, and it is preferable to perform water injection and vacuum devolatilization in multiple stages. In this case, the emulsion polymerization styrene resin (B) and the polycarbonate resin (A) are supplied from the first raw material supply port in the first stage in the same manner as described above in the amount of B (1)> A (1). Then, after being melted by heating, water injection, kneading, devolatilization by a vacuum vent, water injection, kneading, and vacuum venting are further performed in the second stage on the downstream side. There may be a plurality of steps of water injection and vacuum devolatilization in the second stage.

The amount of water to be injected is preferably 0.01 to 5% by mass, more preferably 0 to 100% by mass of the styrene resin (B) and / or the polycarbonate resin (A) that is the target at the time of injection. .1% by mass or more, preferably 0.5% by mass or more, more preferably 3% by mass or less, further 2% by mass or less, and particularly preferably 1% by mass or less. When the amount of water injected is 0.01% by mass or less, the removal of gas generating components tends to be insufficient, and when it exceeds 5% by mass, the hydrolysis of the polymer proceeds and the physical properties tend to be lowered.

Further, the resin temperature (or set temperature) when the resin supplied from the first raw material supply port is melt-kneaded is preferably 240 to 350 ° C., more preferably 250 to 350 ° C. The resin temperature (or set temperature) downstream from the second raw material supply port is preferably 280 to 360 ° C, more preferably 290 to 350 ° C.

In addition, in order to replace all or part of the water injection function described above, it is possible to preliminarily include water in the styrene resin (B). The amount of water contained in advance is preferably about 0.01 to 5% by mass, similar to the amount of water described above.

[Stabilizer]
The polycarbonate resin composition of the present invention preferably contains a stabilizer, and the stabilizer is preferably a phosphorus stabilizer or a phenol stabilizer.

As the phosphorus stabilizer, any known one can be used. Specific examples include phosphorus oxo acids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; acidic pyrophosphate metal salts such as acidic sodium pyrophosphate, acidic potassium pyrophosphate, and acidic calcium pyrophosphate; phosphoric acid Group 1 or Group 2B metal phosphates such as potassium, sodium phosphate, cesium phosphate and zinc phosphate; organic phosphate compounds, organic phosphite compounds, organic phosphonite compounds, etc. Particularly preferred.

Organic phosphite compounds include triphenyl phosphite, tris (monononylphenyl) phosphite, tris (monononyl / dinonyl phenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, monooctyl Diphenyl phosphite, dioctyl monophenyl phosphite, monodecyl diphenyl phosphite, didecyl monophenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, 2,2-methylene bis (4,6-di- tert-butylphenyl) octyl phosphite and the like.
Specific examples of such organic phosphite compounds include, for example, “ADEKA STAB 1178”, “ADEKA STAB 2112”, “ADEKA STAB HP-10” manufactured by ADEKA, “JP-351” manufactured by Johoku Chemical Industry Co., Ltd., “ JP-360 ”,“ JP-3CP ”,“ Irgaphos 168 ”manufactured by BASF, and the like.
In addition, 1 type may contain phosphorus stabilizer and 2 or more types may contain it by arbitrary combinations and a ratio.

The content of the phosphorus stabilizer is usually 0.001 parts by mass or more, preferably 0.01 parts by mass or more, with respect to 100 parts by mass in total of the polycarbonate resin (A) and the styrene resins (B) and (C). More preferably, it is 0.03 parts by mass or more, and is usually 1 part by mass or less, preferably 0.7 parts by mass or less, more preferably 0.5 parts by mass or less. If the content of the phosphorus stabilizer is less than the lower limit of the range, the thermal stability effect may be insufficient, and if the content of the phosphorus stabilizer exceeds the upper limit of the range, the effect May stop and become economical.

Examples of phenolic stabilizers include hindered phenolic antioxidants. Specific examples thereof include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl). ) Propionate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N′-hexane-1,6-diylbis [3- (3,5-di-) tert-butyl-4-hydroxyphenyl) propionamide], 2,4-dimethyl-6- (1-methylpentadecyl) phenol, diethyl [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] ] Methyl] phosphoate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a -(Mesitylene-2,4,6-triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -o-cresol, ethylenebis (oxyethylene) bis [3- (5-tert-butyl- 4-hydroxy-m-tolyl) propionate], hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris (3,5-di-) tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert-butyl-4- (4,6- Bis (octylthio) -1,3,5-triazin-2-ylamino) phenol, 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6 Di -tert- pentylphenyl acrylate.

Among them, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate preferable. Specific examples of such phenolic antioxidants include “Irganox 1010”, “Irganox 1076” manufactured by BASF, “Adekastab AO-50”, “Adekastab AO-60” manufactured by ADEKA, and the like. Is mentioned.
In addition, 1 type may contain the phenol type stabilizer, and 2 or more types may contain it by arbitrary combinations and a ratio.

The content of the phenol-based stabilizer is usually 0.001 part by mass or more, preferably 0.01 part by mass or more with respect to 100 parts by mass in total of the polycarbonate resin (A) and the styrene resin (B) and (C). Moreover, it is 1 mass part or less normally, Preferably it is 0.5 mass part or less. When the content of the phenol-based stabilizer is less than the lower limit of the range, the effect as the phenol-based stabilizer may be insufficient, and the content of the phenol-based stabilizer exceeds the upper limit of the range. If this is the case, the effect may reach its peak and not economical.

In addition, it is preferable to supply the above-mentioned stabilizer and other additives and other resins to be blended as desired together with the polycarbonate resin (A) from the second raw material supply port.

[Release agent]
The polycarbonate resin composition of the present invention preferably contains a release agent. The release agent includes at least one compound selected from the group consisting of aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15000, and polysiloxane silicone oils. Preferably mentioned.

Examples of the aliphatic carboxylic acid include saturated or unsaturated aliphatic monovalent, divalent or trivalent carboxylic acid. Here, the aliphatic carboxylic acid includes alicyclic carboxylic acid. Among these, preferred aliphatic carboxylic acids are monovalent or divalent carboxylic acids having 6 to 36 carbon atoms, and aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms are more preferred. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, mellicic acid, tetrariacontanoic acid, montanic acid, adipine Examples include acids and azelaic acid.

As the aliphatic carboxylic acid in the ester of an aliphatic carboxylic acid and an alcohol, the same aliphatic carboxylic acid as that described above can be used. On the other hand, examples of the alcohol include saturated or unsaturated monovalent or polyhydric alcohols. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, a monovalent or polyvalent saturated alcohol having 30 or less carbon atoms is preferable, and an aliphatic saturated monohydric alcohol or polyhydric alcohol having 30 or less carbon atoms is more preferable. Here, aliphatic includes alicyclic compounds. Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol and the like. Is mentioned.

Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture based on myricyl palmitate), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate Examples thereof include rate, glycerol distearate, glycerol tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate and the like.

Examples of the aliphatic hydrocarbon having a number average molecular weight of 200 to 15000 include liquid paraffin, paraffin wax, microwax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomer having 3 to 12 carbon atoms. Here, as the aliphatic hydrocarbon, alicyclic hydrocarbon is also included. Moreover, these hydrocarbon compounds may be partially oxidized. Among these, paraffin wax, polyethylene wax, or a partial oxide of polyethylene wax is preferable, and paraffin wax and polyethylene wax are more preferable. The number average molecular weight is preferably 200 to 5,000. These aliphatic hydrocarbons may be a single substance, or may be a mixture of various constituent components and molecular weights, as long as the main component is within the above range.

Examples of the polysiloxane silicone oil include dimethyl silicone oil, phenylmethyl silicone oil, diphenyl silicone oil, and fluorinated alkyl silicone. Two or more of these may be used in combination.

When a release agent is used, it is usually 0.05 to 2 parts by mass, preferably 0.1 to 1 part by mass with respect to 100 parts by mass in total of the polycarbonate resin (A) and the styrene resin (B) and (C). It is. If the content of the release agent is not less than the above lower limit value, the effect of improving the releasability can be sufficiently obtained, and if it is not more than the above upper limit value, degradation of hydrolysis resistance due to excessive mixing of the release agent, injection Problems such as mold contamination during molding can be prevented.

[Colorant (dyeing pigment)]
The polycarbonate resin composition of the present invention preferably contains a colorant (dye pigment). Examples of the colorant (dye pigment) include inorganic pigments, organic pigments, and organic dyes.
Examples of inorganic pigments include sulfide pigments such as carbon black, cadmium red, and cadmium yellow; silicate pigments such as ultramarine blue; zinc white, petal, chromium oxide, titanium oxide, iron black, titanium yellow, and zinc- Oxide pigments such as iron-based brown, titanium cobalt-based green, cobalt green, cobalt blue, copper-chromium black, copper-iron-based black; chromic pigments such as yellow lead, molybdate orange; Examples include Russian pigments.
Organic pigments and organic dyes include phthalocyanine dyes such as copper phthalocyanine blue and copper phthalocyanine green; azo dyes such as nickel azo yellow; thioindigo, perinone, perylene, quinacridone, dioxazine, and isoindolinone. And condensed polycyclic dyes such as quinophthalone; anthraquinone, heterocyclic, and methyl dyes and the like. Two or more of these may be used in combination. Among these, carbon black, titanium oxide, cyanine-based, quinoline-based, anthraquinone-based, and phthalocyanine-based compounds are preferable from the viewpoint of thermal stability.

When a colorant (dye pigment) is contained, the content of the colorant (dye pigment) is usually 5 masses with respect to a total of 100 parts by mass of the polycarbonate resin (A), the styrene resin (B), and (C). Part or less, preferably 3 parts by weight or less, more preferably 2 parts by weight or less. When the content of the colorant (dye pigment) exceeds 5 parts by mass, the impact resistance may not be sufficient.

[Other ingredients]
The polycarbonate resin composition of the present invention may contain other components in addition to those described above as necessary, as long as the desired physical properties are not significantly impaired. Examples of other components include resins other than those described above and various resin additives. In addition, 1 type may contain other components and 2 or more types may contain them by arbitrary combinations and ratios.

<Other resins>
Examples of other resins include thermoplastic polyester resins such as polyethylene terephthalate resin, polytrimethylene terephthalate, and polybutylene terephthalate resin; polyolefin resins such as polyethylene resin and polypropylene resin; polyamide resins; polyimide resins; polyetherimide resins; Examples include resins; polyphenylene ether resins; polyphenylene sulfide resins; polysulfone resins and various elastomers.
In addition, 1 type may contain other resin and 2 or more types may contain it by arbitrary combinations and ratios.

<Resin additive>
Examples of the resin additive include a flame retardant, an ultraviolet absorber, an antistatic agent, an antifogging agent, an antiblocking agent, a fluidity improver, a plasticizer, a dispersant, and an antibacterial agent. In addition, 1 type may contain resin additive and 2 or more types may contain it by arbitrary combinations and a ratio.

As described above, in the polycarbonate resin composition of the present invention, the styrenic resin (B) is island-shaped in the matrix of the polycarbonate resin (A) by side-feeding the polycarbonate resin (A) from the second raw material supply port. It was confirmed to show a morphological structure that was finely dispersed. The volume average dispersion diameter (dv) of the styrene resin (B) is characteristically as small as 2.5 μm.

Thus, due to the small volume average dispersion diameter, the resin composition of the present invention has an excellent impact strength retention (wet heat resistance). Specifically, the Charpy impact strength (according to ISO 179-1 and 179-2, with notch, 23 ° C.) after a wet heat treatment at a temperature of 90 ° C. and a relative humidity of 95% for 400 hours is preferably 50% or more. More preferably 60% or more, still more preferably 70% or more, and particularly preferably 80% or more.

The morphology of the polycarbonate resin composition can be observed by observing the cross section of the molded product with an optical microscope, SEM (scanning electron microscope), TEM (transmission electron microscope) or the like.
Specifically, using a SEM, STEM, or TEM analyzer, the pellet cross section is observed at a magnification of 400 to 10,000 times under an acceleration voltage of 3 kv.

1 and 2 show an example of the morphology of the resin composition of the present invention, and are SEM photographs of the pellet cross section obtained in Example 1 of the present invention. 1 is a photograph at a magnification of 1500 times, and FIG. 2 is a photograph at a magnification of 3000 times.
In FIG. 1, the white sea is the matrix phase of the polycarbonate resin, and the black islands dispersed in it are the ABS resin phase, which are finely and finely dispersed in the polycarbonate resin phase. You can see that On the other hand, FIG. 3 (magnification 1500 times) and FIG. 4 (magnification 3000 times) show the morphology of Comparative Example 1, but it can be seen that fine dispersion as shown in FIGS. 1 and 2 cannot be achieved.

As described above, the volume average particle diameter (dv) of the styrene resin in which the styrene resin (B) phase is dispersed in the polycarbonate resin phase is 2.5 μm or less, preferably 2.2 μm or less, more preferably 2 0.0 μm or less, more preferably 1.5 μm or less, and preferably 0.5 μm or more. If the volume average particle diameter (dv) exceeds 2.5 μm, the impact strength retention after wet heat of the resin composition tends to be extremely lowered, which is not preferable.

The ratio (dv / dn) of the volume average particle diameter (dv) and the number average particle diameter (dn) of the styrene resin (B) dispersed in the polycarbonate resin is in the range of 1.0 to 1.5. Preferably, it is 1.1 or more, more preferably 1.15 or more, more preferably 1.45 or less, and further preferably 1.4 or less.
Here, the meaning of the numerical value of dv / dn means a uniform state in which the dispersed particle diameters of the styrenic resin are uniform when dv / dn is 1, and when the particle diameter is larger than 1, the dispersed particle diameters are not uniform and uneven. It is shown that.
Further, this dv / dn is closely related to the volume average diameter (dv) of the dispersed styrene resin described above, except that the dispersed particle diameter is simply uniform. That is, even if dv / dn is in the range of 1.0 to 1.5, if the volume average diameter of the dispersed styrene resin is increased, it is difficult to obtain the effect of improving heat and moisture resistance.
In addition, the average particle diameter (dn) and the volume average particle diameter (dv) of the styrene resin (B) are obtained by observing with a scanning electron microscope (SEM). Details thereof are as described in Examples.

The emulsion-polymerized styrene-based resin (B) exhibits such a volume average particle size (dv) and a morphology having a dv / dn ratio, which means that the emulsion-polymerized styrene-based resin (B) is well melt-kneaded, It can be judged that the devolatilization of the emulsifier-derived component is also highly advanced.

[Molded body]
The polycarbonate resin composition of the present invention is formed by various molding methods, for example, injection molding method, ultra-high speed injection molding method, injection compression molding method, two-color molding method, hollow molding method such as gas assist, molding using a heat insulating mold. Method, molding method using rapid heating mold, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method It is formed into a molded product by a lamination molding method, a press molding method or the like.

Examples of molded products include parts such as electrical and electronic equipment, OA equipment, information terminal equipment, machine parts, home appliances, vehicle parts, building members, various containers, and lighting equipment. Among these, it is particularly suitable for various parts of vehicle parts, electric / electronic devices, and OA devices.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily modified and implemented without departing from the gist of the present invention. In the following description, “parts” means “parts by mass” based on mass standards unless otherwise specified.

Each component used in the following Examples and Comparative Examples is as shown in Table 1 below.

Example 1
A twin-screw extruder “TEX-44α II type” (screw diameter 47 mm, L / D = 59.5) manufactured by Nippon Steel Works was used. This has a first raw material supply port at the base, a water injection port and a vent port in the kneading zone, and then has a second raw material supply port, a water injection port and a vent port. The raw material supply port is provided with a side feeder (“TSF-45E” manufactured by Kubota Corporation) and supplied from there. The screw arrangement includes a full flight screw portion for conveyance, a kneading screw portion for plasticization, and a kneading screw portion for kneading from the supply portion side, and a full flight screw portion for conveyance corresponding to the second raw material supply port. The kneading kneading screw part is provided.

From the first raw material supply port, the emulsion polymerization ABS resin (B1) described in Table 1 was continuously supplied at a supply rate of 105 kg / hr (corresponding to 30 parts by mass). The screw rotation speed is 800 rpm, the cylinder set temperature is 330 ° C., and in the state of being melted in the plasticizing kneading screw part, water is supplied from the water inlet provided in the latter half of the kneading screw part at 0.88 kg / hr. (The ratio of 0.25% by mass with respect to the total discharge amount). A seal ring is provided further rearward of the kneading screw part, and the mixture with water is kneaded with an increase in pressure in the kneading screw part for kneading, and then the vent port provided downstream thereof is in a reduced pressure state of 20 mmHg. Then, foaming devolatilization was performed while the mixture of the resin and water was foamed while being dispersed.
Next, a pre-blend of the polycarbonate resin (A) described in Table 1 and the release agents (D1, D2), stabilizers (E1, E2) and colorant (F) described in Table 1 was supplied to the second supply port. To 245 kg / hr (corresponding to 70 parts by mass). In this preliminary blend, D1 and D2 components are 0.10% by mass, E1 and E2 components are 0.03% by mass and 0.05% by mass, respectively, with respect to 100% by mass of the final resin composition. Blended in such an amount that the F component is 0.5 mass%.
The polycarbonate resin pre-blended product was kneaded while being combined with the devolatilized ABS resin from the upstream at a cylinder set temperature of 330 ° C., and water was again supplied from the water inlet at 0.88 kg / hr (0. 25 mass%). After kneading the mixture with water with a kneading kneading screw part with an increase in pressure, the vent port is reduced in pressure to 20 mmHg, foamed and devolatilized, extruded and strand cut to obtain pellets of the resin composition It was.
The motor current value at the time of extrusion was 236 A, the resin temperature at the die outlet was 333 ° C., and the resin pressure at the die tip was 1.1 MPa. Considering the long-term operational stability of the extruder, these are important because the load on the motor is preferably smaller, and in general, the resin temperature tends to be lower in order to suppress the decomposition of the resin composition. It becomes a judgment index.

(Example 2)
In Example 1, as described in Table 2, in the same manner as in Example 1 except that the water injection amounts of the first stage and the second stage were both 0.5% by mass, Pellets were obtained.

(Example 3)
In Example 1, as described in Table 2, the resin composition was prepared in the same manner as in Example 1 except that the cylinder set temperature was 300 ° C. and the first and second stages of water injection were not performed. Pellets were obtained.

Example 4
In Example 2, as shown in Table 2, pellets of the resin composition were made in the same manner as in Example 2 except that the second stage water injection was not performed and the degree of vacuum at the vent port was 10 mmHg. Got.

(Example 5)
In Example 2, as shown in Table 2, the polycarbonate resin pre-blend was supplied from the first raw material supply port at a feed rate of 87.5 kg / hr (corresponding to 25 parts by mass), and the ABS resin (B1) was 105 kg. / Hr (equivalent to 30 parts by mass), polycarbonate resin is supplied from the second supply port at a rate of 157.5 kg / hr (equivalent to 45 parts by mass), and the degree of vacuum at the vent port is adjusted. Except having set it as 10 mmHg, it carried out similarly to Example 2, and obtained the pellet of the resin composition.

(Example 6)
In Example 1, as shown in Table 3, the styrene resin supplied to the first raw material supply port was 52.5 kg / hr (equivalent to 15 parts by mass) of the emulsion polymerization ABS resin (B2) described in Table 1. And suspension polymerization AS resin (C1) listed in Table 1 at a supply rate of 52.5 kg / hr (corresponding to 15 parts by mass), and the degree of vacuum at the vent port was 10 mmHg. In the same manner as above, pellets of the resin composition were obtained.

(Example 7)
In Example 5, as described in Table 3, the styrene resin supplied to the first raw material supply port was changed to the emulsion polymerization MBS resin (B3) and the suspension polymerization AS resin (C1) described in Table 1. The pellets of the resin composition were obtained in the same manner as in Example 5 except that the amounts of water injected in the first stage and the second stage were both 1.0% by mass. It was.

(Example 8)
In Example 1, as described in Table 3, Example 1 except that the emulsion polymerization ABS resin (B1) and the bulk polymerization ABS resin (C2) were supplied from the first raw material supply port in the amounts shown in Table 3. In the same manner as above, pellets of the resin composition were obtained.

Example 9
In Example 1, as described in Table 3, the styrene resin supplied to the first raw material supply port was 140 kg / hr (equivalent to 40 parts by mass) of the emulsion polymerization ABS resin (B1) described in Table 1. A pellet of the resin composition was obtained in the same manner as in Example 1 except that the polycarbonate resin pre-blend was supplied from the second raw material supply port at a supply rate of 210 kg / hr (corresponding to 60 parts by mass).

(Example 10)
In Example 1, as described in Table 3, the styrene resin supplied to the first raw material supply port was 28 kg / hr (equivalent to 8 parts by mass) of the emulsion polymerization ABS resin (B2) described in Table 1. And the polycarbonate resin preliminary blend was supplied from the second raw material supply port at a supply rate of 322 kg / hr (corresponding to 92 parts by mass), and the degree of vacuum at the vent port was 10 mmHg, as in Example 1, A pellet of the resin composition was obtained.

(Comparative Example 1)
In Example 3, as shown in Table 4, the polycarbonate resin pre-blend from the first raw material supply port was supplied at a feed rate of 245 kg / hr (corresponding to 70 parts by mass), and the ABS resin (B1) was 105 kg / hr. The pellets of the resin composition were obtained in the same manner except that the polycarbonate resin was not supplied from the second supply port.

(Comparative Example 2)
In Example 2, as shown in Table 4, the polycarbonate resin pre-blend from the first raw material supply port was supplied at a feed rate of 245 kg / hr (corresponding to 70 parts by mass), and the ABS resin (B1) was 105 kg / hr. The pellets of the resin composition were obtained in the same manner except that the polycarbonate resin was not supplied from the second supply port.

(Comparative Examples 3 to 4)
In Example 2, as shown in Table 4, the cylinder set temperature was 300 ° C., the polycarbonate resin pre-blend was fed from the first raw material feed port at a feed rate of 140 kg / hr (corresponding to 40 parts by mass), ABS Resin (B1) is supplied at a supply rate of 105 kg / hr (corresponding to 30 parts by mass), and polycarbonate resin is supplied from the second supply port at a supply rate of 105 kg / hr (corresponding to 30 parts by mass). Pellets of the resin composition were obtained in the same manner except that the water injection amount of the stage and the second stage and the degree of vacuum at the vent port were as shown in Table 3.

(Comparative Example 5)
In Example 7, as described in Table 4, the polycarbonate resin pre-blend was supplied from the first raw material supply port at a supply rate of 245 kg / hr (corresponding to 70 parts by mass), and from the second supply port. Resin composition pellets were obtained in the same manner as in Example 7 except that the polycarbonate resin was not supplied and the first and second water injection amounts shown in Table 4 were used.

(Comparative Example 6)
In Comparative Example 2, the styrene resin supplied to the first raw material supply port was 175 kg / hr (equivalent to 50 parts by mass) of the emulsion polymerization ABS resin (B1) described in Table 4, and the second raw material supply port. Resin composition pellets were obtained in the same manner as in Comparative Example 2 except that the polycarbonate resin pre-blend was supplied at a supply rate of 175 kg / hr (corresponding to 50 parts by mass).

(Comparative Example 7)
In Comparative Example 6, the styrene resin supplied to the first raw material supply port was 10.5 kg / hr (corresponding to 3 parts by mass) of the emulsion polymerization ABS resin (B1) described in Table 4 and the bulk polymerization ABS resin (C2 ) 112 kg / hr (corresponding to 32 parts by mass), and Comparative Example 6 except that the polycarbonate resin pre-blend was supplied from the second raw material supply port at a supply rate of 227.5 kg / hr (corresponding to 65 parts by mass). In the same manner as above, pellets of the resin composition were obtained.

[Measurement of amount of gas component in resin composition]
About 20 mg of pellets of the resin composition obtained above are put in a quartz glass sample tube, and using a Shimadzu GCMS thermal desorption system TD-20, under a helium stream (60 ml / min), 280 ° C., 10 minutes. After heating, the generated gas was cooled and collected in a Tenax tube, heated and desorbed, and analyzed by a gas chromatograph mass spectrometer GC / MS consisting of GC-2010Plus and GCMS-QP2010Ultra.
Separation column: UA-5 from Frontier Laboratories
Temperature rising condition: 50 ° C. to 380 ° C. at 10 ° C./min.
Carrier gas: Helium 3ml / min
About the obtained gas, the emulsifier origin component, the oligomer of the styrene resin, and other components (oligomer of polycarbonate resin, raw material monomer of polycarbonate resin, release agent, etc.) were measured by decane conversion. The emulsifier-derived component was measured for the amounts of abietic acid and saturated or unsaturated fatty acids having 12 to 32 carbon atoms. As the fatty acid, oleic acid, stearic acid, palmitic acid or myristic acid was detected in the amounts (unit: mass ppm) shown in Tables 2 to 4.

[Mold contamination]
Using a mini mat M8 / 7A molding machine manufactured by Sumitomo Heavy Industries, Ltd., using a drop mold as shown in FIG. 5, cylinder temperature 260 ° C., mold temperature 60 ° C., injection speed 10 mm / second, molding cycle 100 seconds of continuous molding for 9 seconds, holding pressure of 75 MPa for 1.5 seconds, and cooling time of 2 seconds. After completion, the state of the deposit on the mold was observed with the naked eye, and evaluated according to the following four criteria of A to X. .
The drop mold shown in FIG. 5 is a mold designed so that the resin composition is introduced from the gate G so that the generated gas easily accumulates at the tip. The gate G has a width of 1 mm and a thickness of 1 mm. In FIG. 1, the width h1 is 14.5 mm, the length h2 is 7 mm, the length h3 is 27 mm, and the thickness of the molded part is 3 mm.
<State of mold deposit>
◎: Almost no deposits on the mold and very good mold contamination ○: Although there is a small amount of mold deposits, the mold contamination is good △: There are many deposits on the mold and the mold contamination is poor × : Dust deposits on the whole and mold contamination is extremely poor

[Release evaluation]
The releasability under the above molding conditions was evaluated according to the following three criteria.
○: Continuous molding with 50 shots or more and no defects △: Demolding failure occurs with 10 shots or more and less than 50 shots (molded product does not fall from the ejector pin due to its own weight)
X: 1 to more than 10 shots can be continuously formed
[Appearance evaluation]
The molded product obtained under the above molding conditions was visually judged according to the following criteria, and the appearance was evaluated.
○: Excellent surface gloss and good △: Slightly inferior surface gloss ×: Low surface gloss, rough skin and warping

[Moisture and heat resistance]
The evaluation of wet heat resistance was based on the following impact strength retention after wet heat treatment by wet heat treatment.
After drying the pellets obtained by the above production method at 100 ° C. for 5 hours, using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., Cycap M-2, clamping force 75T), cylinder temperature 250 ° C., gold Under the condition of a mold temperature of 70 ° C., an ISO multipurpose test piece (3 mm thick) was manufactured.
<Impact strength retention after wet heat treatment>
The above ISO multi-purpose test piece (3 mm thick) was subjected to a wet heat treatment for 400 hours in an environment of a temperature of 90 ° C. and a relative humidity of 95%. The notched Charpy impact strength (unit: kJ / m ² ) of the test pieces before and after the wet heat treatment was measured at 23 ° C. according to ISO179.
The impact strength retention after wet heat treatment was calculated based on the following formula.
Impact strength retention after wet heat treatment (%) =
{(Impact strength after wet heat treatment) / (Impact strength before wet heat treatment)} × 100 (%)

[Moisture and heat resistance]
The evaluation of wet heat resistance was evaluated by the rate of increase in MFR value before and after wet heat treatment.
That is, after the pellets of the resin composition are dried at 100 ° C. for 5 hours or more, in accordance with ISO 1133, the measurement temperature is 250 ° C., the load is 2.16 kgf, the temperature is 90 ° C., and the relative humidity is 95%. The MFR (melt flow rate, unit: g / 10 minutes) after the wet heat treatment was measured, and the MFR increase rate (unit:%) after the wet heat treatment was determined by the following formula.
MFR increase rate after wet heat treatment (%) =
{(MFR after wet heat treatment) / (MFR before wet heat treatment)} × 100-100 (%)
It means that it is excellent in heat-and-moisture resistance, so that MFR increase rate (%) after wet heat processing is small.

[Morphological observation]
The obtained pellet was made into a cross-section using an ultramicrotome system UC7 (diamond knife) for section preparation manufactured by Leica, and evaporated to a film thickness of 25 nm using a multi-coater VES-10 manufactured by Vacuum Device Co., Ltd. After that, an image obtained by SEM observation (apparatus: SU8020 manufactured by Hitachi High-Tech, measurement condition: 3 kV-400 to 10000 times, direction perpendicular to the flow direction) is used as image analysis software “A Image-kun” manufactured by Asahi Kasei Engineering. Image analysis was performed.
As a result of image analysis, the diameter (dnj) when converted into a perfect circle from the area of the dispersed particles of the styrene resin is calculated from the following formula, and the number average particle diameter (dn), volume average particle diameter (dv), and volume The ratio (dv / dn) between the average particle diameter (dv) and the number average particle diameter (dn) was determined.

The calculation formula of the diameter (dnj) when converted into a perfect circle from the area of the dispersed particles of the styrene resin is as follows.

In the above formula, A is the particle area of the dispersed styrene resin obtained by image analysis of the SEM photograph.

The calculation formula of the number average particle diameter (dn) of the dispersed styrene resin is as follows.

The formula for calculating the volume average particle diameter (dv) of the dispersed styrene resin is as follows.

The above evaluation results are shown in Tables 2 to 4 below.

The polycarbonate resin composition of the present invention is excellent in mechanical properties and heat-and-moisture resistance, and has no problem of mold contamination due to mold deposit. Therefore, electrical and electronic equipment, OA equipment, information terminal equipment, machine parts, home appliances, vehicle parts, It can be widely used for building members, various containers, lighting equipment, and the like, and according to the production method of the present invention, such a polycarbonate resin composition can be produced with high productivity, so that its industrial utility is high. is there.

Claims (16)

1. (A) and (B) based on a total of 100% by mass, a resin composition comprising 60 to 95% by mass of a polycarbonate resin (A) and 40 to 5% by mass of an emulsion-polymerized styrene resin (B),
   The emulsion polymerization styrene resin (B) is a graft copolymer comprising a styrene monomer-vinyl cyanide monomer and / or an alkyl (meth) acrylate monomer-rubber polymer,
   A polycarbonate resin composition, wherein the total gas amount when the resin composition is heated at 280 ° C. for 10 minutes is 3000 ppm by mass or less in terms of decane mass.
2. In the matrix of the polycarbonate resin (A), the styrene resin (B) is dispersed in an island shape, the volume average dispersion diameter (dv) is 2.5 μm or less, and the volume of the styrene resin (B). The polycarbonate resin composition according to claim 1, wherein the ratio (dv / dn) of the average particle diameter (dv) to the number average particle diameter (dn) is in the range of 1.0 to 1.5.
3. 3. The polycarbonate resin composition according to claim 1, wherein the impact strength retention after heat-moisture treatment for 400 hours in an environment of a temperature of 90 ° C. and a relative humidity of 95% is 50% or more.
4. (A) to (C) based on a total of 100% by mass, polycarbonate resin (A) 60 to 95% by mass, emulsion-polymerized styrene resin (B) 40 to 5% by mass, other styrene other than emulsion-polymerized styrene-based resin A resin composition containing 0 to 30% by mass of a resin based resin (C),
   The emulsion polymerization styrene resin (B) is a graft copolymer comprising a styrene monomer-vinyl cyanide monomer and / or an alkyl (meth) acrylate monomer-rubber polymer,
   A polycarbonate resin composition, wherein the total gas amount when the resin composition is heated at 280 ° C. for 10 minutes is 3000 ppm by mass or less in terms of decane mass.
5. The polycarbonate resin composition according to claim 4, wherein the other styrene resin (C) is a suspension polymerization or a block polymerization styrene resin.
6. The polycarbonate resin composition according to claim 4 or 5, wherein the other styrene resin (C) is a suspension polymerization AS resin.
7. The polycarbonate resin composition according to any one of claims 4 to 6, wherein the other styrene-based resin (C) is a block polymerization ABS resin.
8. The emulsion-polymerized styrene resin (B) is dispersed in islands in the matrix of the polycarbonate resin (A), the volume average dispersion diameter (dv) is 2.5 μm or less, and the emulsion-polymerized styrene resin ( The polycarbonate according to any one of claims 1 to 7, wherein the ratio (dv / dn) of the volume average particle diameter (dv) to the number average particle diameter (dn) of B) is in the range of 1.0 to 1.5. Resin composition.
9. The polycarbonate resin composition according to any one of claims 1 to 8, which has an impact strength retention rate of 50% or more after wet-heat treatment for 400 hours in an environment of a temperature of 90 ° C and a relative humidity of 95%.
10. A molded article of the polycarbonate resin composition according to any one of claims 1 to 9.
11. A polycarbonate resin composition containing 60 to 95% by weight of a polycarbonate resin (A) and 40 to 5% by weight of an emulsion-polymerized styrene resin (B) based on a total of 100% by weight of (A) and (B). A method of manufacturing by melt-kneading with an extruder,
    The extruder has a first raw material supply port on the upstream side and one or more second raw material supply ports on the downstream side thereof,
    The supply amount of the emulsion polymerization styrene resin (B) is B (1), the supply amount of the polycarbonate resin (A) from the first raw material supply port is A (1), and the second raw material supply of the polycarbonate resin (A). When the supply amount from the mouth is A (2), the sum of A (1) and A (2) is the total supply amount of the polycarbonate resin (A),
    From the first raw material supply port, styrene resin (B) and polycarbonate resin (A),
    Formula: B (1)> A (1) (However, A (1) includes 0.)
    Supply to meet and
    After melt-kneading, after degassing the gas component from the vent port under reduced pressure,
    A method for producing a polycarbonate resin composition, comprising: supplying a polycarbonate resin (A) in an amount of A (2) from a second raw material supply port downstream of the vent port.
12. The method for producing a polycarbonate resin composition according to claim 11, wherein the gas component contains a gas component derived from an emulsifier.
13. A polycarbonate resin composition containing 60 to 95% by weight of a polycarbonate resin (A) and 40 to 5% by weight of an emulsion-polymerized styrene resin (B) based on a total of 100% by weight of (A) and (B). A method of manufacturing by melt-kneading with an extruder,
    The extruder has a first raw material supply port on the upstream side and a water injection part and a vent port in the kneading part on the downstream side, and further has one or more second raw material supply ports on the downstream side. And
    The supply amount of the emulsion polymerization styrene resin (B) is B (1), the supply amount of the polycarbonate resin (A) from the first raw material supply port is A (1), and the second raw material supply of the polycarbonate resin (A). When the supply amount from the mouth is A (2), the sum of A (1) and A (2) is the total supply amount of the polycarbonate resin (A),
    From the first raw material supply port, styrene resin (B) and polycarbonate resin (A),
    Formula: B (1)> A (1) (However, A (1) includes 0.)
    Supply to meet and
    Then, after injecting water from the water injection part provided in the kneading part and melt-kneading, after degassing the gas component from the vent port,
    A method for producing a polycarbonate resin composition, characterized in that the polycarbonate resin (A) is supplied in an amount of A (2) from a second raw material supply port downstream of the vent port.
14. The method for producing a polycarbonate resin composition according to claim 13, wherein the gas component contains a gas component derived from an emulsifier.
15. The method for producing a polycarbonate resin composition according to claim 13 or 14, wherein the vent type twin screw extruder is an extruder having a water injection part and a vent port in multiple stages, and water injection and vacuum devolatilization are performed in multiple stages.
16. A molded product obtained by molding the polycarbonate resin composition obtained by the production method of claims 11 to 15.

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