JP2018048258A - Method for producing polycarbonate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate having excellent scratch resistance on nails, excellent scratch resistance for eliminating slight scratches even at low hardness in a pencil hardness test, excellent in fluidity and appearance, and excellent in hue and transparency. Providing a resin composition. A graft copolymer having a polyethylene polymer as a main chain and a vinyl polymer segment as a side chain with respect to 100 parts by mass of a polycarbonate resin (A) containing a structural unit represented by the formula (1). (B) A method for producing a polycarbonate resin composition by melt-kneading 0.1 to 25 parts by mass with a twin-screw extruder, and the resin temperature T2 at the die outlet with respect to the average temperature T1 of the cylinder of the extruder is as follows. A method for producing a polycarbonate resin composition satisfying the formula. 10°C ≤ T2-T1 ≤ 30°C [Selection diagram] None

Description

  The present invention relates to a method for producing a polycarbonate resin composition, and more specifically, excellent scratch resistance on nails, excellent scratch resistance that eliminates even slight scratches at low hardness in a pencil hardness test, and fluidity and appearance. And a method for stably producing a polycarbonate resin composition having excellent hue and transparency.

  Polycarbonate resins are excellent in mechanical strength, electrical characteristics, transparency, and the like, and are widely used as engineering plastics in various fields such as electrical and electronic equipment fields and automobile fields. In recent years, in these fields of use, molding products have become thinner, smaller, and lighter, and further improvements in the performance of molding materials have been demanded. Among them, the development of polycarbonate resins with high hardness has become desirable. Some suggestions have been made.

  For example, polycarbonate having excellent surface hardness using an aromatic dihydroxy compound having a specific structure different from conventional bisphenol A such as 2,2-bis (3-methyl-4-hydroxyphenyl) propane, that is, bisphenol C, and the like Known methods include copolycarbonates (Patent Documents 1 and 2), a method of blending a dimethylbisphenolcyclohexane type polycarbonate and a bisphenol A type polycarbonate (Patent Document 3), and the like.

JP-A-64-069625 Japanese Patent Laid-Open No. 08-183852 International Publication No. 2009/083933

Certainly, bisphenol C-based polycarbonate resin has a high pencil hardness of 2H. However, when this molded product is actually used as a product, there is a slight problem in scratch resistance, such as being easily scratched when rubbed with a nail. I found out. Although the pencil hardness itself must be an important index for scratch resistance, it has been found that this alone is not necessarily sufficient as scratch resistance. The pencil hardness is pressed against the surface of the sample at a load of 750 g at 45 °, moved by pressing, and the scratch hardness of the sample is represented by the hardness of the pencil core (6B to HB to 9H) depending on whether there is a scratch. Although it is a test method, a bisphenol C-based polycarbonate resin exhibits a high pencil hardness of 2H, and when the above measurement operation is performed with a pencil having a hardness lower than 2H, a slight scratch is formed on the surface of the test piece. Turned out to be. Pencil hardness has been established as a method for evaluating the surface hardness of plastics, and there is a strong demand for the occurrence of slight scratches at such low pencil hardness.
An object (problem) of the present invention is to provide a polycarbonate resin using an aromatic dihydroxy compound having a specific structure different from that of conventional bisphenol A such as bisphenol C, and is excellent in scratch resistance in nails and low in a pencil hardness test. Manufacture of polycarbonate resin composition that stably eliminates slight scratches in hardness, excellent scratch resistance, excellent fluidity and appearance, and also excellent in hue and transparency It is to provide a method.

As a result of intensive studies to achieve the above-mentioned problems, the present inventor has obtained a polyethylene polymer as a polycarbonate resin using an aromatic dihydroxy compound having a specific structure different from that of conventional bisphenol A such as bisphenol C. When a specific amount of a graft copolymer having a vinyl polymer segment as a side chain is blended in the main chain and melt-kneaded with a twin screw extruder to produce a polycarbonate resin composition, the average temperature of the cylinder of the extruder It has been found that the above problem can be solved by setting the resin temperature at the die outlet to a specific relationship, and the present invention has been completed.
The present invention relates to the following method for producing a polycarbonate resin composition.

[1] Graft copolymer having a polyethylene polymer as a main chain and a vinyl polymer segment as a side chain with respect to 100 parts by mass of a polycarbonate resin (A) containing a structural unit represented by the following general formula (1) A method for producing a polycarbonate resin composition by melting and kneading 0.1 to 25 parts by mass of a combined body (B) with a twin screw extruder,
A method for producing a polycarbonate resin composition, wherein a resin temperature T2 at a die outlet with respect to an average temperature T1 of a cylinder of the extruder satisfies a condition of the following formula.
10 ° C ≦ T2-T1 ≦ 30 ° C
(In general formula (1), R ¹ represents a methyl group, R ² and R ³ each independently represents a hydrogen atom or a methyl group, and X represents an alkylene group or an alkylidene group.)

[2] The method for producing a polycarbonate resin composition according to the above [1], wherein the graft copolymer (B) is a graft copolymer having a polyethylene polymer main chain having a styrene polymer segment as a side chain.
[3] The graft copolymer (B) according to the above [1], wherein the graft copolymer (B) is a graft copolymer comprising at least 50 to 95% by mass of a polyethylene polymer segment and 5 to 50% by mass of a vinyl polymer segment. A method for producing a polycarbonate resin composition.
[4] The polycarbonate resin composition according to any one of [1] to [3], wherein the graft copolymer (B) is a graft copolymer further containing 0.5 to 30% by mass of a polyorganosiloxane segment. Manufacturing method.
[5] The graft copolymer (B) according to any one of [1] to [4], wherein the endothermic peak temperature measured by a differential scanning calorimeter (DSC) is 100 ° C. or less in accordance with JIS K7121. A process for producing a polycarbonate resin composition.
[6] Furthermore, the polycarbonate-polyorganosiloxane copolymer (C) is contained in any one of the above [1] to [5] containing 5 to 200 parts by mass with respect to 100 parts by mass of the polycarbonate resin (A). A process for producing a polycarbonate resin composition.

  The production method of the present invention is excellent in scratch resistance on nails, excellent in scratch resistance that eliminates even slight scratches at low hardness in the pencil hardness test, excellent in fluidity and appearance, and hue and transparency It is possible to stably produce an excellent polycarbonate resin composition.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention is not limited to the following embodiments and examples and the like, and is within the scope of the present invention. Any change can be made.

The method for producing a polycarbonate resin composition of the present invention is based on 100 parts by mass of the polycarbonate resin (A) having the structural unit represented by the general formula (1), and a vinyl polymer having a polyethylene polymer as a main chain. A method for producing a polycarbonate resin composition by melt-kneading 0.1 to 25 parts by mass of a graft copolymer (B) having a segment as a side chain with a twin screw extruder, the average temperature of the cylinder of the extruder The resin temperature T2 at the die outlet with respect to T1 satisfies the following formula.
10 ° C ≦ T2-T1 ≦ 30 ° C

[Polycarbonate resin (A)]
The polycarbonate resin (A) used in the method for producing a polycarbonate resin composition of the present invention is a polycarbonate resin containing a structural unit represented by the following general formula (1).
(In general formula (1), R ¹ represents a methyl group, R ² and R ³ each independently represents a hydrogen atom or a methyl group, and X represents an alkylene group or an alkylidene group.)

In the general formula (1), R ¹ is a methyl group, and R ² and R ³ are each independently a hydrogen atom or a methyl group, but R ² and R ³ are particularly preferably a hydrogen atom.
X is an alkylene group or an alkylidene group, and the alkylene group is preferably an alkylene group having 1 to 6 carbon atoms, and may be linear or branched. Examples thereof include methylene, 1,2-ethylene, 1,3-propylene, 1,4-butylene, 1,6-hexylene and the like.
The alkylidene group is preferably an alkylidene group having 2 to 10 carbon atoms, and examples thereof include ethylidene, 2,2-propylidene, 2,2-butylidene, and 3,3-hexylidene.
X is preferably an alkylidene group, particularly preferably a 2,2-propylidene group (that is, an isopropylidene group).

Preferable specific examples of the polycarbonate resin (A) include the following polycarbonate resins (a) to (b).
A) Those having a 2,2-bis (3-methyl-4-hydroxyphenyl) propane structural unit, that is, a structural unit in which R ¹ is a methyl group, R ² and R ³ are hydrogen atoms, and X is an isopropylidene group Having
B) 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane structural unit, that is, a structural unit in which R ¹ is a methyl group, R ² and R ³ are methyl groups, and X is an isopropylidene group thing,
Of the above, the polycarbonate resin (a) is particularly preferable.

  These polycarbonate resins are produced using 2,2-bis (3-methyl-4-hydroxyphenyl) propane and 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane as dihydroxy compounds. be able to.

  As the polycarbonate resin (A), one type may be used, or two or more types may be used in any combination and in any ratio.

The polycarbonate resin (A) may be a polycarbonate resin having a carbonate structural unit other than the structural unit represented by the general formula (1), for example, a structural unit represented by the following general formula (2), or It may have a structural unit derived from another dihydroxy compound as described later. In this case, the copolymerization amount of the structural unit other than the structural unit represented by the general formula (1) is usually less than 50 mol%, preferably 40 mol% or less, more preferably 30 mol% or less, Is preferably 20 mol% or less, particularly preferably 10 mol% or less.
(Wherein X has the same meaning as X in formula (1)).

A preferred specific example of the polycarbonate structural unit represented by the general formula (2) is 2,2-bis (4-hydroxyphenyl) propane, that is, a carbonate structural unit derived from bisphenol A.
When the polycarbonate resin (A) contains a carbonate structural unit derived from bisphenol A as a copolymerization component, the component derived from bisphenol A is preferably less than 50 mol%, more preferably 30% by mass or less, still more preferably It is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less.

  Examples of dihydroxy compounds other than the structural unit represented by the general formula (2) include bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis ( 4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxyphenyl) decane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) phenylmethane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxy) Phenyl) cyclooctane, 9,9-bis (4-hydroxyphenyl) fluorene, 4,4′-dihydroxybenzophenone, , 4'-dihydroxyphenyl ether, and the like preferably.

  The viscosity average molecular weight (Mv) of the polycarbonate resin (A) is preferably 19,000 to 32,000. When the viscosity average molecular weight is in this range, a molded product with good moldability, high mechanical strength and good scratch resistance can be easily obtained. When the viscosity average molecular weight is less than 19,000, the pencil hardness of the resin composition is lowered. In addition, the wear resistance tends to decrease, and if it exceeds 32,000, the melt viscosity increases and injection molding tends to be difficult. The lower limit of the molecular weight of the polycarbonate resin (A) is more preferably 20,000, still more preferably 22,000, particularly 24,000, and the upper limit is preferably 30,000, more preferably 28,000. .

In the present invention, the viscosity average molecular weight [Mv] of the polycarbonate resin is determined by using methylene chloride as a solvent and determining the intrinsic viscosity [η] (unit dl / g) at a temperature of 20 ° C. using an Ubbelohde viscometer, It is a value calculated from the following Schnell viscosity equation.
[Η] = 1.23 × 10 ⁻⁴ Mv ^0.83

  The polycarbonate resin (A) has a carbonate structural unit other than the structural unit represented by the general formula (1), such as the polycarbonate resin (A) containing the structural unit represented by the general formula (1). It may be a mixture with a polycarbonate resin. When such other polycarbonate resin is mixed, it is less than 50% by mass based on the total of 100% by mass of both, preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less. It is preferable.

As the other polycarbonate resin when the polycarbonate resin (A) is a mixture with another polycarbonate resin other than the structural unit represented by the general formula (1), the polycarbonate structure represented by the general formula (2) is used. A polycarbonate resin composed of units is preferred, and a preferred specific example thereof is 2,2-bis (4-hydroxyphenyl) propane, that is, a carbonate resin derived from bisphenol A.
This may be a copolymer having a structural unit derived from another dihydroxy compound other than the structural unit represented by the general formula (2). Examples thereof include bis (4-hydroxyphenyl) methane, 2, 2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxy) Phenyl) decane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) phenylmethane, 1,1-bis ( 4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclooctane, 9,9-bis (4-hydroxyphenyl) ) Fluorene, 4,4'-dihydroxybenzophenone, the unit derived from 4,4'-dihydroxy phenyl ether preferably.

  The polycarbonate resin (A) is defined as different from the polycarbonate-polyorganosiloxane copolymer (C) described later, and the polycarbonate resin (A) includes the polycarbonate-polyorganosiloxane copolymer (C). It is not a thing.

  The viscosity average molecular weight (Mv) of other polycarbonate resins that may be mixed with the polycarbonate resin (A) is preferably 15,000 to 30,000. When the viscosity average molecular weight is within this range, it is easy to obtain a molded product having good moldability, high mechanical strength, and good scratch resistance. When the viscosity average molecular weight is less than 15,000, the pencil hardness of the resin composition is lowered. In addition, the wear resistance tends to decrease, and if it exceeds 30,000, the melt viscosity increases and injection molding tends to be difficult. The lower limit of the molecular weight of the polycarbonate resin (A) is more preferably 20,000, even more preferably 22,000, particularly 24,000, and the upper limit is preferably 28,000, more preferably 26,000. .

Manufacturing method of polycarbonate resin The manufacturing method of the polycarbonate resin used for this invention is not specifically limited, Arbitrary methods are employable. Examples thereof include an interfacial polymerization method, a melt transesterification method, a pyridine method, a ring-opening polymerization method of a cyclic carbonate compound, and a solid phase transesterification method of a prepolymer.
Hereinafter, a particularly preferable one of these methods will be described in detail.

Interfacial Polymerization Method First, a case where a polycarbonate resin is produced by an interfacial polymerization method will be described.
In the interfacial polymerization method, a dihydroxy compound and a carbonate precursor (preferably phosgene) are reacted in the presence of an organic solvent inert to the reaction and an aqueous alkaline solution, usually at a pH of 9 or higher. Polycarbonate resin is obtained by interfacial polymerization in the presence. In the reaction system, a molecular weight adjusting agent (terminal terminator) may be present as necessary, or an antioxidant may be present to prevent the oxidation of the dihydroxy compound.

  The dihydroxy compound and the carbonate precursor are as described above. Of the carbonate precursors, phosgene is preferably used, and a method using phosgene is particularly called a phosgene method.

  Examples of the organic solvent inert to the reaction include chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane, chloroform, monochlorobenzene and dichlorobenzene; aromatic hydrocarbons such as benzene, toluene and xylene; It is done. In addition, 1 type may be used for an organic solvent and it may use 2 or more types together by arbitrary combinations and a ratio.

  Examples of the alkali compound contained in the alkaline aqueous solution include alkali metal compounds and alkaline earth metal compounds such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and sodium hydrogen carbonate, among which sodium hydroxide and water Potassium oxide is preferred. In addition, 1 type may be used for an alkali compound and it may use 2 or more types together by arbitrary combinations and a ratio.

  Although there is no restriction | limiting in the density | concentration of the alkali compound in alkaline aqueous solution, Usually, in order to control pH in the alkaline aqueous solution of reaction to 10-12, it is used at 5-10 mass%. For example, when phosgene is blown, the molar ratio of the bisphenol compound and the alkali compound is usually 1: 1.9 or more in order to control the pH of the aqueous phase to be 10 to 12, preferably 10 to 11. Among these, it is preferable that the ratio is 1: 2.0 or more, usually 1: 3.2 or less, and more preferably 1: 2.5 or less.

  Examples of the polymerization catalyst include aliphatic tertiary amines such as trimethylamine, triethylamine, tributylamine, tripropylamine, and trihexylamine; alicyclic rings such as N, N′-dimethylcyclohexylamine and N, N′-diethylcyclohexylamine. Formula tertiary amines; aromatic tertiary amines such as N, N′-dimethylaniline and N, N′-diethylaniline; quaternary ammonium salts such as trimethylbenzylammonium chloride, tetramethylammonium chloride, triethylbenzylammonium chloride, etc. Pyridine salt; and the like. In addition, 1 type may be used for a polymerization catalyst and it may use 2 or more types together by arbitrary combinations and a ratio.

  Examples of the molecular weight regulator include aromatic phenols having a monohydric phenolic hydroxyl group; aliphatic alcohols such as methanol and butanol; mercaptans; phthalimides and the like. Of these, aromatic phenols are preferred. Specific examples of such aromatic phenols include alkyl groups such as m-methylphenol, p-methylphenol, m-propylphenol, p-propylphenol, p-tert-butylphenol, and p-long chain alkyl-substituted phenol. Examples thereof include substituted phenols; vinyl group-containing phenols such as isopropenyl phenol; epoxy group-containing phenols; carboxyl group-containing phenols such as o-hydroxybenzoic acid and 2-methyl-6-hydroxyphenylacetic acid; In addition, a molecular weight regulator may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The usage-amount of a molecular weight regulator is 0.5 mol or more normally with respect to 100 mol of dihydroxy compounds, Preferably it is 1 mol or more, and is 50 mol or less normally, Preferably it is 30 mol or less. By making the usage-amount of a molecular weight modifier into this range, the thermal stability and hydrolysis resistance of a resin composition can be improved.

In the reaction, the order of mixing the reaction substrate, reaction medium, catalyst, additive and the like is arbitrary as long as a desired polycarbonate resin is obtained, and an appropriate order may be arbitrarily set. For example, when phosgene is used as the carbonate precursor, the molecular weight regulator can be mixed at any time as long as it is between the reaction (phosgenation) of the dihydroxy compound and phosgene and the start of the polymerization reaction.
In addition, reaction temperature is 0-40 degreeC normally, and reaction time is normally several minutes (for example, 10 minutes)-several hours (for example, 6 hours).

Next, a case where a polycarbonate resin is produced by a melt transesterification method will be described.
In the melt transesterification method, for example, a transesterification reaction between a carbonic acid diester and a dihydroxy compound is performed.

The dihydroxy compound is as described above.
On the other hand, examples of the carbonic acid diester include dialkyl carbonate compounds such as dimethyl carbonate, diethyl carbonate, and di-tert-butyl carbonate; diphenyl carbonate; substituted diphenyl carbonate such as ditolyl carbonate, and the like. Among these, diphenyl carbonate and substituted diphenyl carbonate are preferable, and diphenyl carbonate is more preferable. In addition, carbonic acid diester may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of the dihydroxy compound and the carbonic acid diester is arbitrary as long as the desired polycarbonate resin is obtained, but it is preferable to use an equimolar amount or more of the carbonic acid diester with respect to 1 mol of the dihydroxy compound, and above all, 1.01 mol or more. It is more preferable. The upper limit is usually 1.30 mol or less. By setting it as such a range, the amount of terminal hydroxyl groups can be adjusted to a suitable range.

  In the polycarbonate resin, the amount of terminal hydroxyl groups tends to have a great influence on thermal stability, hydrolysis stability, color tone and the like. For this reason, you may adjust the amount of terminal hydroxyl groups as needed by a well-known arbitrary method. In the transesterification reaction, a polycarbonate resin in which the amount of terminal hydroxyl groups is adjusted can be usually obtained by adjusting the mixing ratio of the carbonic diester and the aromatic dihydroxy compound; the degree of vacuum during the transesterification reaction, and the like. In addition, the molecular weight of the polycarbonate resin usually obtained can also be adjusted by this operation.

When adjusting the amount of terminal hydroxyl groups by adjusting the mixing ratio of the carbonic acid diester and the dihydroxy compound, the mixing ratio is as described above.
Further, as a more aggressive adjustment method, there may be mentioned a method in which a terminal terminator is mixed separately during the reaction. Examples of the terminal terminator at this time include monohydric phenols, monovalent carboxylic acids, carbonic acid diesters, and the like. In addition, 1 type may be used for a terminal terminator and it may use 2 or more types together by arbitrary combinations and a ratio.

  When producing a polycarbonate resin by the melt transesterification method, a transesterification catalyst is usually used. Any transesterification catalyst can be used. Among them, it is preferable to use, for example, an alkali metal compound and / or an alkaline earth metal compound. In addition, auxiliary compounds such as basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds may be used in combination. In addition, 1 type may be used for a transesterification catalyst and it may use 2 or more types together by arbitrary combinations and a ratio.

  In the melt transesterification method, the reaction temperature is usually 100 to 320 ° C. Moreover, the pressure during the reaction is usually carried out under a reduced pressure of less than normal pressure, and the reduced pressure state is adjusted according to the progress of the reaction, and finally it is preferably set to a condition of 2 mmHg or less. As a specific operation, a melt polycondensation reaction may be performed under the above-mentioned conditions while removing a by-product such as an aromatic hydroxy compound.

  The melt polycondensation reaction can be performed by either a batch method or a continuous method. When performing by a batch type, the order which mixes a reaction substrate, a reaction medium, a catalyst, an additive, etc. is arbitrary as long as a desired aromatic polycarbonate resin is obtained, What is necessary is just to set an appropriate order arbitrarily. However, considering the stability of the polycarbonate resin and the like, the melt polycondensation reaction is preferably carried out continuously.

  In the melt transesterification method, a catalyst deactivator may be used as necessary. As the catalyst deactivator, a compound that neutralizes the transesterification catalyst can be arbitrarily used. Examples thereof include sulfur-containing acidic compounds and derivatives thereof. In addition, 1 type may be used for a catalyst deactivator and it may use 2 or more types together by arbitrary combinations and a ratio.

  The amount of the catalyst deactivator used is usually 0.5 equivalents or more, preferably 1 equivalent or more, and usually 10 equivalents or less, relative to the alkali metal or alkaline earth metal contained in the transesterification catalyst. Preferably it is 5 equivalents or less. Furthermore, it is 1 ppm or more normally with respect to polycarbonate resin, and is 100 ppm or less normally, Preferably it is 20 ppm or less.

[Graft Copolymer (B)]
The polycarbonate resin composition of the present invention contains a graft copolymer (B) having a polyethylene polymer as a main chain and a vinyl polymer segment as a side chain. In this graft copolymer (B), a polyethylene polymer serves as a main chain of the graft copolymer, and a segment obtained by polymerizing a vinyl monomer serves as a side chain of the graft copolymer.

The polyethylene polymer constituting the main chain may be either an ethylene homopolymer or a copolymer with other α-olefins other than ethylene, which is mainly composed of ethylene and copolymerizable therewith.
The α-olefin other than ethylene is an α-olefin having usually 3 to 20 carbon atoms, preferably 3 to 12 carbon atoms, and propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1 Preferred examples include -pentene, 1-octene, 1-decene, 1-dodecene and the like.
When the polyethylene polymer is a copolymer, the amount of the α-olefin unit is usually 0 to 50% by mass, preferably 0 to 30% by mass, more preferably 0 to 20% by mass, and further 0 to 10% by mass. It is preferable that

  The molecular weight of the polyethylene polymer is usually about 10,000 to 600,000 in terms of number average molecular weight (Mn). Here, the number average molecular weight means what is calculated | required as polystyrene conversion by a gel permeation chromatograph (GPC).

  Polyethylene polymers include commercially available high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE), or high pressure methods obtained by high pressure radical methods. Any of low density ethylene (HPLD) and the like may be used, but low density polyethylene, linear low density polyethylene, very low density polyethylene, and high pressure method low density polyethylene are preferable, and very low density polyethylene (VLDPE) is more preferable. preferable.

The low density polyethylene has a density of usually 0.91 to 0.94 g / cm ³ , preferably 0.912 to 0.935 g / cm ³ . The linear low density polyethylene preferably has a density of 0.91 to 0.94 g / cm ³ . Ultra low density polyethylene is a copolymer of ethylene and α-olefin, and usually has a density in the range of 0.86 to 0.91 g / cm ³ . The high pressure method low density polyethylene by the high pressure method preferably has a density of 0.91 to 0.94 g / cm ³ .

  Examples of vinyl monomers for forming vinyl polymer segments include styrene monomers, α, β-unsaturated carboxylic acids, α, β-unsaturated carboxylic acid esters, unsaturated nitrile monomers. A body etc. are mentioned preferably.

Examples of the styrene monomer include styrene, methyl styrene, dimethyl styrene, ethyl styrene, isopropyl styrene, chlorostyrene, and the like, and styrene is particularly preferable.
Examples of the α, β-unsaturated carboxylic acid include (meth) acrylic acid esters such as hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate, acrylic acid, and methacrylic acid. Preference is given to fumaric acid, maleic anhydride, itaconic acid and the like.
Examples of the α, β-unsaturated carboxylic acid ester include methyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, and n methacrylate. Preferred examples include -butyl and isobutyl methacrylate.
As the unsaturated nitrile monomer, acrylonitrile is preferably exemplified.

  Among these vinyl monomers, styrene monomers, particularly styrene, are preferred because they are highly compatible with the polycarbonate resin (A) and have excellent scratch resistance effects. Styrene alone or styrene, It is preferable to copolymerize with OH group-containing (meth) acrylate such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, or acrylonitrile.

  The molecular weight of the vinyl polymer segment is preferably 5,000 to 500,000 in terms of mass average molecular weight. Here, a mass average molecular weight means what is calculated | required as polystyrene conversion by a gel permeation chromatograph (GPC).

  It is also preferred that the graft copolymer (B) further contains a polyorganosiloxane. When the polyorganosiloxane is contained, the graft copolymer (B) may have as a main chain or a side chain, and may be one of the graft copolymers that forms a multi-layer structure such as a core / shell type. It may be contained as a part.

The polyorganosiloxane is not particularly limited, but representative examples thereof include polydimethylsiloxane and polymethylphenylsiloxane, and examples thereof include polydimethyldiphenylsiloxane copolymer, polydimethylphenylmethylsiloxane copolymer, and polymethylphenyldiphenylsiloxane copolymer. Among them, a polymer containing a dialkylsiloxane unit, particularly a dimethylsiloxane unit as a constituent unit is preferable.
Moreover, as polyorganosiloxane, what contains the siloxane containing a vinyl group as a structural component is preferable. Siloxanes containing vinyl groups are well known and contain vinyl groups to which organosiloxanes are bonded via siloxane bonds.

The proportion of the polyethylene polymer segment in the graft copolymer (B) is preferably 50 to 95% by mass, more preferably 60 to 90% by mass, and still more preferably 65 to 80% by mass. is there. The proportion of the vinyl polymer segment is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and still more preferably 20 to 35% by mass.
Further, the content when the polyorganosiloxane segment is further contained is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass, and further preferably 2 to 10% by mass. . However, when a polyorganosiloxane segment is contained, the polyethylene polymer segment, the vinyl polymer segment and the polyorganosiloxane segment are combined to 100 mass%.

The graft copolymer (B) preferably has an endothermic peak temperature measured by a differential scanning calorimeter (DSC) in accordance with JIS K7121 at 100 ° C. or lower. This is preferable because scratch resistance with a nail when blended with a polycarbonate resin and slight scratch resistance at low hardness in a pencil hardness test are good. This is because the endothermic peak temperature is 100 ° C. or lower, so that the polyethylene polymer main chain having a low affinity with the polycarbonate resin easily enters between the polycarbonate resin molecules, and the affinity with the polycarbonate resin is improved. This is presumably because the dispersion of the graft copolymer (B) phase in the polycarbonate resin phase becomes good.
The graft copolymer (B) may have a plurality of endothermic peaks. Even when there are a plurality of endothermic peaks, the graft copolymer (B) preferably has an endothermic peak at 100 ° C. or lower. The endothermic peak temperature is preferably 90 ° C. or lower, more preferably 80 ° C. or lower, and its lower limit is usually 60 ° C. or higher.

  In the present invention, the endothermic peak of the graft copolymer (B) is measured according to JIS K7121, using a differential scanning calorimeter DSC7020 manufactured by Seiko Instruments Inc. It is performed by observing a 10 mg sample by raising the temperature from 30 ° C. to 300 ° C. at a rate of 10 ° C./min. The graft copolymer (B) has a plurality of endothermic peaks, and the temperature of the endothermic peak on the lowest temperature side is measured.

  In order to produce the graft copolymer (B), any of various known graft copolymerization methods may be used, and examples thereof include the following methods.

  That is, the polyethylene polymer is suspended in water, and the vinyl monomer, radical polymerizable organic peroxide (for example, t-butyl peroxymethacryloyloxyethyl carbonate, etc.), polymerization initiator ( For example, a mixed solution in which 3,5,5-trimethylhexanoyl peroxide or the like is dissolved is added and then heated to copolymerize to produce a graft copolymer.

  The graft copolymer (B) is commercially available and can be used. For example, it is sold as “Nofalloy (registered trademark) KA series” by NOF Corporation, for example, “Nofalloy KA147”. Etc. are available.

  The content of the graft copolymer (B) is 0.1 to 25 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts with respect to 100 parts by mass of the above-described polycarbonate resin (A). Parts by weight. When the amount is less than 0.1 parts by mass, the scratch resistance at the nail and the effect of improving slight scratches at low hardness in the pencil hardness test are reduced. When the amount exceeds 25 parts by mass, the hue is deteriorated and the mechanical strength is reduced. In addition, the heat resistance is reduced.

[Production Method of Polycarbonate Resin Composition]
The method for producing a polycarbonate resin composition of the present invention comprises mixing the above-described components (A), (B), or each component described later in a predetermined quantitative ratio, melt-kneading with a twin screw extruder, and polycarbonate resin composition. In producing (pellet), the resin temperature T2 at the die outlet with respect to the average temperature T1 of the cylinder of the extruder satisfies the formula: 10 ° C. ≦ T2−T1 ≦ 30 ° C.

Examples of the melt kneader include a kneader, a roll mill, a single screw extruder, a twin screw extruder, and the like. In the present invention, a twin screw extruder is used. The twin-screw extruder has two rotating shafts, and there are the same-direction rotating type and the different-direction rotating type, but both can be used in the present invention, but the same-direction rotating type is used. be able to. The twin-screw extruder may be a multi-screw extruder or a twin / single-screw composite extruder.
The above-mentioned raw material components are normally continuously supplied from the base supply port of the twin screw extruder using a quantitative feeder such as a screw feeder, table feeder, belt feeder or the like so that the ratio of each component is always constant. And melt kneaded. In addition, as long as the twin-screw extruder has a side feeder, some or all of each component may be supplied from the side feeder.

In the present invention, the temperature difference between the average temperature T1 of the cylinder and the resin temperature T2 at the die outlet, that is, T2-T1 is set in the range of 10 ° C to 30 ° C.
Usually, it is preferable to lower the resin temperature at the die outlet because the discoloration of the obtained polycarbonate resin composition (pellet) is suppressed. However, by setting T2-T1 in such a range, yellowing is less and transparent. A polycarbonate resin composition (pellet) having high properties and low haze can be obtained. The reason for this is to increase the dispersibility of the graft copolymer (B) in the polycarbonate resin composition while keeping the dispersion of the resin temperature in the extruder uniform by making T2-T1 in such a range. It is estimated that this is possible. T2-T1 is preferably 13 ° C or higher, more preferably 15 ° C or higher, preferably 27 ° C or lower, more preferably 25 ° C or lower. When T2-T1 is too large, the resin temperature becomes too high, and the color tone of the polycarbonate resin composition deteriorates and yellows, which is not preferable. In the case of an ordinary polycarbonate resin composition, T2-T1 is considered to be preferably 0 (zero), but the polycarbonate resin (A) of the present invention and a polyethylene polymer are the main chain, and the vinyl polymer segment is the side chain. In the case of the polycarbonate composition containing the graft copolymer (B) to be prepared, if T2-T1 is too low, the dispersibility of the graft copolymer (B) is deteriorated and the transparency is lowered, which is not preferable.
Here, the resin temperature at the die outlet is preferably a resin temperature in the vicinity of the die outlet, which can be measured by a temperature sensor attached to the die outlet. However, when it is difficult to directly measure the resin temperature due to restrictions on the structure of the extruder, the set temperature is applied.
The average temperature of the cylinder is the average temperature of the heating temperature of the cylinder heater installed in the extruder, and can be measured by a temperature sensor installed in the cylinder.

The average temperature T1 of the cylinder is preferably in the range of 240 ° C to 320 ° C, more preferably 250 ° C to 300 ° C, and most preferably 255 ° C to 280 ° C.
The resin temperature T2 at the die outlet is preferably in the range of 250 ° C to 330 ° C, more preferably 260 ° C to 310 ° C, and most preferably 270 ° C to 290 ° C.

In order to set T2-T1 to 10 ° C. to 30 ° C., it is also possible to adjust screw diameter (D), screw length (L), L / D, screw rotation speed, resin supply amount, and resin residence time. However, it is possible by setting and controlling the set temperature of the cylinder inner surface and the set temperature of the die outlet.
The screw speed of the extruder is usually preferable because the yellowing of the color tone of the resin composition obtained is suppressed as much as possible. However, in the method of the present invention, kneading is enhanced by increasing the speed. Thus, the transparency can be improved while controlling the hue of the resin. The screw speed varies depending on the screw diameter (D), screw length (L), L / D, blending ratio of each component, resin supply amount, etc., but is preferably about 100 to 300 rpm, more preferably 150 to 260 rpm.

Next, the polycarbonate resin composition is extruded in a strand form from the die outlet of the extruder, and usually introduced into water and cooled. There is no restriction | limiting in particular in the shape of an extrusion die, A well-known thing is used. The diameter of the die of the discharge nozzle is usually about 2 to 5 mm, although it depends on the extrusion pressure and the desired pellet size.
The resin strand is taken up by the take-up roller and cooled by being transported in the water stored in the cooling tank. In order to reduce the deterioration of the resin, it is better that the time from when the strand is pushed out of the die until entering the water is shorter. Normally, it is better to enter the water within 1 second after being pushed out of the die.
The cooled strand is sent to a pelletizer by a take-off roller, and is cut into pellets.

[Polycarbonate-polyorganosiloxane copolymer (C)]
It is preferable that a polycarbonate-polyorganosiloxane copolymer (C) is further blended in the method for producing a polycarbonate resin composition of the present invention.
The polycarbonate-polyorganosiloxane copolymer (C) comprises a polycarbonate part and a polyorganosiloxane part. The polyorganosiloxane part in the polycarbonate-polyorganosiloxane copolymer (C) is preferably a segment composed of polydimethylsiloxane, polydiethylsiloxane, polymethylphenylsiloxane, etc., and particularly preferably a polydimethylsiloxane segment.

  The polycarbonate-polyorganosiloxane copolymer (C) is, for example, a polycarbonate oligomer constituting a polycarbonate part produced in advance, and an o-allylphenol residue or a p-hydroxystyrene residue at the terminal constituting the polyorganosiloxane part. Polyorganosiloxane having a reactive group such as eugenol residue is dissolved in a solvent such as methylene chloride, chlorobenzene, chloroform, and a caustic aqueous solution of dihydric phenol is added, and a tertiary amine (triethylamine or the like) is added as a catalyst. ) Or a quaternary ammonium salt (such as trimethylbenzylammonium chloride) and can be produced by interfacial polycondensation reaction in the presence of a terminal terminator.

  The polycarbonate oligomer used for the production of the polycarbonate-polyorganosiloxane copolymer (C) is obtained by reacting a dihydric phenol with a carbonate precursor such as phosgene in a solvent such as methylene chloride, or It can be easily produced by reacting a hydric phenol with a carbonate ester compound, for example, a carbonate precursor such as diphenyl carbonate.

Examples of the dihydric phenol include the same compounds as those described above for the polycarbonate resin of the general formula (2) or the general formula (1), and in particular, 2,2-bis (4-hydroxyphenyl) propane. (Ie, bisphenol A), bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 4, 4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) cycloalkane, bis (4-hydroxyphenyl) oxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) Preferable examples include sulfoxide and bis (4-hydroxyphenyl) ketone. Can do. Of these, bis (hydroxyphenyl) alkanes are more preferable, and 2,2-bis (4-hydroxyphenyl) propane is particularly preferable.
A dihydric phenol may be used independently and may be used in combination of 2 or more type.

  Examples of the carbonate precursor include carbonyl halide, carbonyl ester, haloformate, and the like, and specifically phosgene, dihaloformate of dihydric phenol, diphenyl carbonate, dimethyl carbonate, and diethyl carbonate. Examples of the carbonate compound include diaryl carbonates such as diphenyl carbonate, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate.

The polycarbonate oligomer used for the production of the polycarbonate-polyorganosiloxane copolymer (C) may be a homo-oligomer using one kind of dihydric phenol described above, or a co-oligomer using two or more kinds. Also good.
Furthermore, the thermoplastic random branched oligomer obtained by using a polyfunctional aromatic compound together with the dihydric phenol mentioned above may be sufficient.
In that case, 1,1,1-tris (4-hydroxyphenyl) ethane, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, 1 -[Α-Methyl-α- (4'-hydroxyphenyl) ethyl] -4- [α ', α'-bis (4''-hydroxyphenyl) ethyl] benzene, phloroglucin, trimellitic acid, isatin bis (o- Cresol) and the like can be used.

  Such a polycarbonate-polyorganosiloxane copolymer (C) is disclosed in, for example, JP-A-50-29695, JP-A-3-292359, JP-A-4-202466, and the like.

As the polycarbonate-polyorganosiloxane copolymer (C), those having a polymerization degree of the polycarbonate part of about 3 to 100 and a polymerization degree of the polyorganosiloxane part of about 2 to 500 are preferably used.
The content of the polyorganosiloxane part in the polycarbonate-polyorganosiloxane copolymer (C) is preferably 2 to 10% by mass, more preferably 2.2 to 7% by mass, and particularly preferably 2.5 to 5%. % By mass.

The viscosity-average molecular weight (Mv) of the polycarbonate-polyorganosiloxane copolymer (C) is usually 5,000 to 100,000, preferably 10,000 to 30,000, particularly preferably 12,000 to 30,000. 000.
These viscosity average molecular weights (Mv) are values obtained in the same manner as the method described in the section of the polycarbonate resin (A).

Further, polycarbonate - polyorganosiloxane copolymer (C) has a melt volume rate measured at 300 ℃ / 1.2kg (MVR) ^is preferably in the 1~35cm 3 / 10min, more preferably 2 to it is a 30cm ³ / 10min.

  Content of a polycarbonate polyorganosiloxane copolymer (C) is 5-200 mass parts with respect to 100 mass parts of polycarbonate resin (A), Preferably it is 10-150 mass parts, More preferably, it is 40-120. Parts by weight. When the amount is less than 5 parts by mass, the haze increases and the transparency becomes low. When the amount exceeds 200 parts by mass, the pencil hardness decreases, scratch resistance at the nails, and slight scratch resistance at low hardness in the pencil hardness test. Cause a decline.

[Stabilizer (D)]
It is preferable to mix | blend a stabilizer (D) with the manufacturing method of the polycarbonate resin composition of this invention. Examples of the stabilizer (D) in the present invention include an antioxidant and a heat stabilizer. In the present invention, an antioxidant or a heat stabilizer may be used alone, but it is preferable to use both an antioxidant and a heat stabilizer in combination.

[Antioxidant]
Examples of the antioxidant that can be applied to the method for producing the polycarbonate resin composition of the present invention include hindered phenol 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, etc. These may be contained only in one kind, and two or more kinds in any combination and ratio Or it may be closed.

  Among the above, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate is preferred. These two phenolic antioxidants are commercially available from BASF Japan under the names “Irganox (registered trademark, the same applies hereinafter) 1010” and “Irganox 1076”.

  Content of antioxidant is 0.001-1 mass part normally with respect to 100 mass parts of polycarbonate resin (A), Preferably it is 0.01-0.5 mass part. When the content of the antioxidant is less than 0.001 part by mass, the effect as an antioxidant is insufficient, and when it exceeds 1 part by mass, the effect reaches a peak and is not economical.

[Thermal stabilizer]
As a heat stabilizer suitable for the method for producing the polycarbonate resin composition of the present invention, for example, a phosphorus compound may be mentioned. Any known phosphorous compound 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-methylenebis (4,6-di- tert-butylphenyl) octyl phosphite and the like.
Specific examples of such an organic phosphite compound include, for example, “ADEKA STAB (registered trademark, the same applies hereinafter) 1178”, “ADEKA STAB 2112”, “ADEKA STAB HP-10” manufactured by ADEKA Corporation, and Johoku Chemical Industry Co., Ltd. Examples thereof include “JP-351”, “JP-360”, “JP-3CP” manufactured by company, “Irgaphos (registered trademark) 168” manufactured by BASF Japan Ltd., and the like.
In addition, the heat stabilizer may be contained only by 1 type and 2 or more types may be contained by arbitrary combinations and ratios.

  The content of the heat stabilizer is usually 0.001 parts by mass or more, preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more with respect to 100 parts by mass of the polycarbonate resin (A). Usually, it is 1 part by mass or less, preferably 0.5 part by mass or less, more preferably 0.3 part by mass or less. If the content of the heat stabilizer is less than the lower limit value of the range, the heat stability effect may be insufficient, and if the content of the heat stabilizer exceeds the upper limit value of the range, the effect reaches a peak. And may become less economical.

[Release agent]
In the method for producing the polycarbonate resin composition of the present invention, it is also preferable to contain a release agent. Examples of the release agent include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, polysiloxane silicone oils, and the like.

  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, preferable 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 preferable. 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 aliphatic carboxylic acid in ester of aliphatic carboxylic acid and alcohol, the same thing as the said aliphatic carboxylic acid can be used, for example. On the other hand, examples of the alcohol include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, monovalent or polyvalent saturated alcohols having 30 or less carbon atoms are preferable, and aliphatic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols having 30 or less carbon atoms are more preferable. In addition, an aliphatic includes an alicyclic compound here.

  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.

  In addition, said ester may contain aliphatic carboxylic acid and / or alcohol as an impurity. Moreover, although said ester may be a pure substance, it may be a mixture of a plurality of compounds. Furthermore, the aliphatic carboxylic acid and alcohol which combine and comprise one ester may each be used 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  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 15,000 include liquid paraffin, paraffin wax, microwax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomer having 3 to 12 carbon atoms. Here, the aliphatic hydrocarbon includes alicyclic hydrocarbons. Further, these hydrocarbons may be partially oxidized. The number average molecular weight is preferably 5,000 or less. The aliphatic hydrocarbon may be a single substance, but even a mixture of various constituent components and molecular weights can be used as long as the main component is within the above range.

  Among these, paraffin wax, polyethylene wax, or a partial oxide of polyethylene wax is preferable, paraffin wax and polyethylene wax are more preferable, and polyethylene wax is particularly preferable.

In addition, 1 type may contain the mold release agent and 2 or more types may contain it by arbitrary combinations and a ratio.
The content of the release agent is usually 0.001 parts by mass or more, preferably 0.01 parts by mass or more, and usually 2 parts by mass or less, preferably 1 with respect to 100 parts by mass of the polycarbonate resin (A). It is below mass parts. When the content of the release agent is less than the lower limit of the above range, the effect of releasability may not be sufficient, and when the content of the release agent exceeds the upper limit of the above range, hydrolysis resistance And mold contamination during injection molding may occur.

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

  Examples of other resin additives include ultraviolet absorbers, flame retardants, anti-dripping agents, antistatic agents, antifogging agents, lubricants, antiblocking agents, plasticizers, dispersants, antibacterial agents, and the like. In addition, 1 type may contain resin additive and 2 or more types may contain it by arbitrary combinations and a ratio.

[Molding]
The polycarbonate resin composition (pellet) obtained by the production method of the present invention is molded into various molded articles by various molding methods.
The shape of the molded product is not particularly limited and can be appropriately selected according to the use and purpose of the molded product. For example, a plate shape, a plate shape, a rod shape, a sheet shape, a film shape, a cylindrical shape, an annular shape, Examples include a circular shape, an elliptical shape, a polygonal shape, an irregular shape, a hollow shape, a frame shape, a box shape, and a panel shape.

The method for molding a molded product is not particularly limited, and a conventionally known molding method can be employed.For example, an injection molding method, an injection compression molding method, an extrusion molding method, a profile extrusion method, a transfer molding method, a hollow molding method, Gas assisted hollow molding method, blow molding method, extrusion blow molding, IMC (in-mold coating molding) molding method, rotational molding method, multilayer molding method, two-color molding method, insert molding method, sandwich molding method, foam molding method And a pressure molding method.
Among these, the molding is preferably performed by an injection molding method. For example, the molding is performed using a known injection molding machine such as an injection molding machine, an ultra-high speed injection molding machine, or an injection compression molding machine. The cylinder temperature of the injection molding machine at the time of injection molding is preferably 240 to 320 ° C, more preferably 250 to 300 ° C, and further preferably 260 to 280 ° C. The injection speed during injection molding is preferably 10 to 1,000 mm / second, more preferably 10 to 500 mm / second.

  The molded article of the polycarbonate resin composition of the present invention can be used in a wide range of fields, such as electronic and electrical equipment and parts thereof, OA equipment, information terminal equipment, mechanical parts, home appliances, vehicle parts, building members, and various types. It is useful for various applications such as containers, leisure goods / miscellaneous goods, lighting equipment, etc., and can be expected to be applied particularly to electronic electrical equipment, OA equipment, information terminal equipment materials, and vehicle interior parts.

Electronic electrical equipment, OA equipment, and information terminal equipment include personal computers, game consoles, television display devices, printers, copiers, scanners, fax machines, electronic notebooks and PDAs, cameras, video cameras, mobile phones, tablet terminals And a member such as a touch panel type portable device.
Vehicle interior parts include inner door handles, center panels, instrument panels, console boxes, luggage floor boards, door pockets, displays for car navigation, and the like.
Among them, a molded product from the polycarbonate resin composition obtained by the method of the present invention is excellent in scratch resistance and appearance, and is also excellent in transparency. Therefore, various tablet-type mobile terminals such as smartphones, tablet-type personal computers, etc. It is particularly suitable as a liquid crystal display panel member such as car navigation and car audio, particularly as a cover member for a touch panel.

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

  In Table 1 above, (A1) and (A2) used as the polycarbonate resin (A) were produced by the following Production Example 1 and Production Example 2, respectively.

<Production Example 1: Production of polycarbonate resin (A1)>
2,2-bis (3-methyl-4-hydroxyphenyl) propane (hereinafter referred to as “BPC”) 26.14 mol (6.75 kg) and diphenyl carbonate 26.79 mol (5.74 kg) The reactor was placed in a SUS reactor (with an internal volume of 10 liters) equipped with a stirrer and a distillation condenser, and after the inside of the reactor was replaced with nitrogen gas, the temperature was raised to 220 ° C. over 30 minutes in a nitrogen gas atmosphere.
Next, the reaction solution in the reactor is stirred, and cesium carbonate (Cs ₂ CO ₃ ) is used as a transesterification reaction catalyst in the molten reaction solution so that the amount becomes 1.5 × 10 ⁻⁶ mol per 1 mol of BPC. In addition, the reaction solution was stirred and brewed at 220 ° C. for 30 minutes in a nitrogen gas atmosphere. Next, under the same temperature, the pressure in the reactor was reduced to 100 Torr over 40 minutes, and the reaction was further performed for 100 minutes to distill phenol.
Next, the temperature in the reactor was raised to 284 ° C. over 60 minutes and the pressure was reduced to 3 Torr, and phenol corresponding to almost the entire distillation amount was distilled. Next, the pressure in the reactor was kept below 1 Torr at the same temperature, and the reaction was further continued for 60 minutes to complete the polycondensation reaction. At this time, the stirring rotation speed of the stirrer was 38 rotations / minute, the reaction liquid temperature just before the completion of the reaction was 289 ° C., and the stirring power was 0.75 kW.
Next, the reaction solution in a molten state is fed into a twin screw extruder, and 4-fold molar amount of butyl p-toluenesulfonate is supplied from the first supply port of the twin screw extruder with respect to cesium carbonate, After kneading with the reaction solution, the reaction solution was extruded in a strand shape through a die of a twin screw extruder and cut with a cutter to obtain carbonate resin pellets.

The physical properties of the obtained polycarbonate resin (A1) were as follows.
Pencil hardness: 2H
Viscosity average molecular weight (Mv): 22,000

(Examples 1-4, Comparative Examples 1-5)
Each component described in Table 1 above was blended in the proportions shown in Table 2 below (all expressed in parts by mass) and uniformly mixed with a tumbler mixer, and then a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.). Using TEM26SX, screw: 2-stage kneading type, diameter 26 mm, L / D = 48.5), supply amount (kg / hr), screw rotation speed (rpm), cylinder average temperature T1 ( The mixture was melt-kneaded at 0 ° C., extruded from a die at the tip of the screw at a resin temperature T2 shown in Table 2, introduced into water, cooled, and cut with a pelletizer to obtain a pellet of a polycarbonate resin composition.

[Total light transmittance (unit:%) and haze (unit:%)]
The pellets obtained by the above method are injection-molded on an injection molding machine (J55AD-60H manufactured by Nippon Steel Works) under the conditions of a cylinder temperature of 260 ° C., a mold temperature of 80 ° C., and a molding cycle of 50 seconds, and ISO A multipurpose specimen (2 mm thick) was produced.
Using the obtained ISO multi-purpose test piece (2 mm thickness) according to JIS K7105, using an NDH-2000 type haze meter manufactured by Nippon Denshoku Industries Co., Ltd. Unit:%) was measured. Moreover, the haze (unit:%) in 2 mm thickness was also measured.

[Yellow Index of Polycarbonate Resin Composition (YI)]
In the same manner as described above, a three-stage plate having a 1.0 mm thick portion, a 2.0 mm thick portion, and a 3.0 mm thick portion was injection molded. Of the obtained three-stage plate, a portion having a thickness of 2.0 mm is yellow in accordance with JIS K7105 (1981) using a spectral color difference meter (SE2000 manufactured by Nippon Denshoku Industries Co., Ltd.) with a C light source transmission method. The index (YI) value was measured.

[Measurement of pencil hardness]
A flat test piece (90 mm × 50 mm × 2 mm thickness) was produced in the same manner as described above. About this flat test piece, the pencil hardness measured by a 750 g load was calculated | required using the pencil hardness tester (made by Toyo Seiki Co., Ltd.) based on ISO15184.

[Judgment of slight scratches with low pencil hardness]
When the pencil hardness measurement was performed with a pencil having a hardness of 3B to 3H using the above flat test piece, the presence or absence of slight scratches was confirmed visually and with a microscope (50 times magnification). Judged by the criteria of.
A: The occurrence of slight scratches is not confirmed at all.
◯: Although slight scratches cannot be confirmed by visual observation, slight scratches are slightly confirmed by a microscope (magnification 50 times).
X: The occurrence of scratches can be clearly confirmed.

[Evaluation of scratching by nails]
The surface of the flat test piece (90 mm × 50 mm × 2 mm thick) was rubbed with a nail tip of a solid nail without manicure, and the scratch resistance by the nail was evaluated by the following visual judgment.
○: No scratches were confirmed even when rubbed strongly.
Δ: It is confirmed that scratches occur when rubbed strongly.
X: It can be clearly confirmed that scratches are generated.
The above evaluation results are shown in Tables 2 to 4 below.

  According to the method for producing a polycarbonate resin composition of the present invention, a polycarbonate resin material having excellent scratch resistance and appearance, and also having excellent transparency can be stably produced. There is.

Claims (6)

A graft copolymer (B) having a polyethylene polymer as a main chain and a vinyl polymer segment as a side chain with respect to 100 parts by mass of a polycarbonate resin (A) containing a structural unit represented by the following general formula (1) ) A method for producing a polycarbonate resin composition by melt-kneading 0.1 to 25 parts by mass with a twin screw extruder,
A method for producing a polycarbonate resin composition, wherein a resin temperature T2 at a die outlet with respect to an average temperature T1 of a cylinder of the extruder satisfies a condition of the following formula.
10 ° C ≦ T2-T1 ≦ 30 ° C
(In general formula (1), R ¹ represents a methyl group, R ² and R ³ each independently represents a hydrogen atom or a methyl group, and X represents an alkylene group or an alkylidene group.)   2. The method for producing a polycarbonate resin composition according to claim 1, wherein the graft copolymer (B) is a graft copolymer having a polyethylene polymer main chain having a styrene polymer segment as a side chain.   2. The polycarbonate resin composition according to claim 1, wherein the graft copolymer (B) is a graft copolymer comprising at least 50 to 95% by mass of a polyethylene polymer segment and 5 to 50% by mass of a vinyl polymer segment. Production method.   The method for producing a polycarbonate resin composition according to any one of claims 1 to 3, wherein the graft copolymer (B) is a graft copolymer further containing 0.5 to 30% by mass of a polyorganosiloxane segment.   The polycarbonate resin composition according to any one of claims 1 to 4, wherein the graft copolymer (B) has an endothermic peak temperature measured by a differential scanning calorimeter (DSC) in accordance with JIS K7121 at 100 ° C or lower. Production method.   Furthermore, the polycarbonate-polyorganosiloxane copolymer (C) is contained in 5 to 200 parts by mass with respect to 100 parts by mass of the polycarbonate resin (A). Production method.