JP2011021127A - Housing for portable electronic appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a housing for a portable electronic appliance, which has a small wall thickness, excellent drop impact resistance, flowability and heat resistance. <P>SOLUTION: The housing for the portable electronic appliance is obtained by molding a polycarbonate resin composition comprising: 10-100 pts.mass of a polycarbonate-polyorganosiloxane copolymer (A-1) which is a block copolymer having a polycarbonate block and a polyorganosiloxane block and has a content of polyorganosiloxane block part of 1-30 mass% and has an average repeating unit number of siloxane unit of 70-1,000 and a viscosity-average molecular weight of 13,000-26,000 and 0-90 pts.mass of an aromatic polycarbonate (A-2) other than the component (A-1) to make the total 100 pts.mass. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a housing for storing an electronic device or the like, and more specifically, a thin-walled, drop-resistant product formed by molding a polycarbonate resin composition containing a polycarbonate-polyorganosiloxane copolymer having a specific structure. The present invention relates to a portable electronic device casing having excellent impact, fluidity and heat resistance.

Resin materials are often used for housings of portable electronic devices such as portable personal computers, personal digital assistants (PDAs), cellular phones, portable players, and battery cases.
Assuming that an electronic device is accidentally dropped while being carried, in order to protect the internal electronic device, it is necessary to guarantee the shock resistance of the housing so as not to cause cracking or destruction of the housing.
However, since the thermal properties such as impact strength and heat distortion temperature of resin materials are inferior to those of metal materials, the thickness of molded products such as housings is increased, or alloy materials that are blended with resin materials are used. Attempts have been made to improve mechanical characteristics and thermal characteristics by using or filling a plastic material with an inorganic filler or an organic filler to form a fiber-reinforced plastic.
In general, increasing the strength of a casing is a very difficult technique for plastic material molding, and in particular, in the field of injection molding with excellent mass productivity, there is a constant demand for improvement of resin materials.
Therefore, in selecting a resin material, impact resistance is taken into consideration, and a material having particularly high impact strength is desired.
Furthermore, in injection molding, residual stress is likely to occur in the molded product due to molecular orientation distortion and cooling strain. Therefore, when a material with a low heat distortion temperature is used, the residual stress is released in a high temperature use environment. Therefore, a material having a high thermal deformation temperature is desired.

2. Description of the Related Art As a resin composition for a mobile phone casing, a polycarbonate resin is known in which a rubber component is added for the purpose of improving impact strength (see, for example, Patent Document 1).
When a polycarbonate-polydimethylsiloxane copolymer having a polydimethylsiloxane (PDMS) portion having a repeating number n of dimethylsiloxane units of 100 to 400, specifically n of 150 to 350, is mixed with glass fiber, the impact resistance is improved. Although it is known that the effect is difficult to be obtained when the decrease is small and the number of repetitions n is 100 or less, the description regarding the PDMS structure and the number of repetitions affecting the impact resistance when the influence of the glass fiber is excluded. In addition, even if the examples are seen, the effect of the number of repetitions on the impact strength is not seen (see, for example, Patent Document 2).
Further, it is known that a polycarbonate-polydimethylsiloxane copolymer having a dimethylsiloxane unit repeating number n of 40 to 60, specifically n of 49, exhibits good low temperature impact characteristics (see, for example, Patent Document 3). ).
Further, a method for obtaining a transparent polycarbonate-polydimethylsiloxane copolymer having a PDMS part having a dimethylsiloxane unit repeating number n of 50 (see, for example, Patent Document 4), and the dimethylsiloxane unit repeating number n of 0 to 20 Transparent and flame-retardant polycarbonate-polydimethylsiloxane copolymer having a PDMS portion (see, for example, Patent Document 5), PDMS having a siloxane unit repetition number n of 2 to 500, specifically n is 30 or 150 A flame retardant resin composition comprising a polycarbonate-polydimethylsiloxane copolymer having a moiety is known (see, for example, Patent Document 6).
However, a polycarbonate resin composition for a portable electronic device casing that can be thinned and has excellent drop impact resistance, fluidity, and heat resistance is not known.

JP 2006-176612 A Japanese Patent No. 2662310 JP-T-2006-523243 JP-T-2005-535761 JP 2005-519177 A JP-A-8-81620

  The present invention has been made in order to solve the above-mentioned problems of the prior art, and is a thin wall formed by molding a polycarbonate resin composition containing a polycarbonate-polyorganosiloxane copolymer having a specific structure. An object of the present invention is to provide a portable electronic device casing having excellent drop impact resistance, fluidity, and heat resistance.

As a result of intensive studies to achieve the above object, the present inventor can achieve the object by molding a polycarbonate resin composition containing a polycarbonate-polyorganosiloxane copolymer having a specific structure. I found.
The present invention has been completed based on such findings.

［式中、Ｒ¹及びＲ²は、それぞれ独立に炭素数1〜６のアルキル基又はアルコキシ基、Ｘは単結合、炭素数１〜８のアルキレン基、炭素数２〜８のアルキリデン基、炭素数５〜１５のシクロアルキレン基、炭素数５〜１５のシクロアルキリデン基、−Ｓ−、−ＳＯ−、−ＳＯ₂−、−Ｏ−又は−ＣＯ−、Ｒ³及びＲ⁴は、それぞれ独立に、水素原子、ハロゲン原子又は置換基を有していてもよいアルキル基もしくはアリール基を示し、ａ及びｂは、それぞれが独立に０〜４の整数を示す。］、
２．射出成形により成形する上記１に記載の携帯型電子機器筐体、
３．携帯型電子機器筐体の肉厚が０．５〜１．５ｍｍである上記２に記載の携帯型電子機器筐体、
４．携帯型電子機器筐体の携帯型電子機器が携帯電話機である上記２又は３に記載の携帯型電子機器筐体
を提供するものである。 That is, the present invention
1. The content of the polyorganosiloxane block part having the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II) and including the structural unit represented by the general formula (II) is A polycarbonate-polyorganosiloxane copolymer (A-) having an average number of repeating units of 70 to 1000 and a viscosity average molecular weight of 13,000 to 26000 in the structural unit of the general formula (II) is 1 to 30% by mass. 1) Molding a polycarbonate resin composition containing 10 to 100 parts by mass and 0 to 90 parts by mass of an aromatic polycarbonate (A-2) other than (A-1) so that the total amount becomes 100 parts by mass. Portable electronic device housing,

[Wherein, R ¹ and R ² are each independently an alkyl group or alkoxy group having 1 to 6 carbon atoms, X is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, carbon A cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, —S—, —SO—, —SO ₂ —, —O— or —CO—, R ³ and R ⁴ are each independently , A hydrogen atom, a halogen atom or an optionally substituted alkyl group or aryl group, a and b each independently represent an integer of 0 to 4. ],
2. The portable electronic device housing according to 1 above, which is molded by injection molding,
3. The portable electronic device casing according to 2 above, wherein the thickness of the portable electronic device casing is 0.5 to 1.5 mm,
4). The portable electronic device casing according to 2 or 3 above, wherein the portable electronic device of the portable electronic device casing is a mobile phone.

  According to the present invention, by molding a polycarbonate resin composition containing a polycarbonate-polyorganosiloxane copolymer having a specific structure, the impact strength can be greatly improved without sacrificing the fluidity of the polycarbonate, A portable electronic device casing that is thin and excellent in drop impact resistance, fluidity, and heat resistance can be provided.

FIG. 1 is an explanatory diagram of dimensions of a cellular phone model type molded product (50 mm × 88 mm, depth 4.5 mm, thickness 1.2 mm) using the resin compositions of Examples 1 to 7 and Comparative Examples 1 and 2. It is.

  The portable electronic device casing of the present invention has a structural unit represented by the general formula (I) and a structural unit represented by the general formula (II), and includes a structural unit represented by the general formula (II). The content of the polyorganosiloxane block part is 1 to 30% by mass, the average number of repeating units of the structural unit of the general formula (II) is 70 to 1000, and the viscosity average molecular weight is 13,000 to 26000. 10 to 100 parts by mass of the polycarbonate-polyorganosiloxane copolymer (A-1) and 0 to 90 parts by mass of the aromatic polycarbonate (A-2) other than (A-1) so that the total amount becomes 100 parts by mass. The polycarbonate resin composition contained in is molded.

[Wherein, R ¹ and R ² are each independently an alkyl group or alkoxy group having 1 to 6 carbon atoms, X is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, carbon A cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, —S—, —SO—, —SO ₂ —, —O— or —CO—, R ³ and R ⁴ are each independently , A hydrogen atom, a halogen atom or an optionally substituted alkyl group or aryl group, a and b each independently represent an integer of 0 to 4. ],

The content of the polyorganosiloxane block part containing the structural unit represented by the general formula (II) is preferably 1 to 20% by mass, and if it is less than 1.0% by mass, the effect of improving the drop impact resistance is obtained. It is not sufficient, and when it exceeds 30% by mass, the heat resistance is greatly lowered.
Moreover, the average number of repeating units of the structural unit of the general formula (II) is preferably 80 to 700, more preferably 80 to 500, and if it is less than 70, the effect of improving the drop impact strength is not sufficient. When it exceeds 1, handling property at the time of manufacturing a polydimethylsiloxane-polycarbonate copolymer (A-1) will become difficult, and it will be inferior to economical efficiency.

In general, it is effective that the viscosity-average molecular weight of the polycarbonate-polyorganosiloxane copolymer (A-1) is large in order to develop the drop impact resistance. However, if the viscosity-average molecular weight is large, the portable electronic device housing It becomes difficult to form a thin member such as a body.
It is possible to lower the viscosity of the resin composition by raising the molding temperature, but in that case, the molding cycle becomes longer and inferior in economic efficiency. Decreases.
Therefore, the viscosity average molecular weight of the polycarbonate-polyorganosiloxane copolymer (A-1) is preferably 14,000 to 23,000, more preferably 15,000 to 22,000.
When the viscosity average molecular weight is less than 13000, the strength of the molded product is not sufficient, and when it exceeds 26000, the viscosity of the copolymer increases, so that productivity at the time of production is reduced and thin-wall molding becomes difficult.
The polycarbonate resin composition of the present invention is a composition containing the component (A-1) and the component (A-2) so that the total amount becomes 100 parts by mass, and is a polycarbonate-polyorganosiloxane copolymer. The content of (A-1) is preferably 50 to 100 parts by mass, more preferably 60 to 95 parts by mass, and the content of aromatic polycarbonate (A-2) other than (A-1) is preferably Is 50 to 0 parts by mass, more preferably 40 to 5 parts by mass.
When the content of the polycarbonate-polyorganosiloxane copolymer (A-1) is less than 10 parts by mass, the polyorganosiloxane containing the structural unit represented by the general formula (II) at the time of producing the component (A-1) It is necessary to make the content of the block part 30% by mass or more. In this case, the uniformity of the reaction is lowered in the polymerization step at the time of producing the component (A-1), or the polymer is washed with the polymer washing step. Since the separability with water deteriorates, the productivity of the component (A-1) is greatly reduced.
When the content of the aromatic polycarbonate (A-2) other than (A-1) exceeds 90 parts by mass, the content of the component (A-1) becomes less than 10 parts by mass, which is not preferable for the above reason.

Next, the polycarbonate-polyorganosiloxane copolymer (A-1) will be described.
The polycarbonate-polyorganosiloxane copolymer used in the present invention is composed of a dihydric phenol represented by the general formula (1) and a polyorganosiloxane represented by the general formula (2).

[In general formula (1), X, R ^{1 to} R ² and a and b are the same as in general formula (I), and n represents an integer of 70 to 1000 in terms of the average number of repeating units of the organosiloxane constituent unit. In the general formula (2), R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom, or an optionally substituted alkyl group or aryl group, Y represents a halogen, —R ⁷ OH, —R ⁷ COOH, —R ⁷ NH ₂ , —COOH or —SH, wherein R ⁷ may have a linear, branched or cyclic alkylidene group, an aryl-substituted alkylidene group, or an alkoxy group on the ring. An aryl-substituted alkylene group and an aryl group are represented, and m represents 0 or 1. ]
And phosgene, carbonate ester, or chloroformate is obtained by copolymerization, and the ratio of the polyorganosiloxane block portion containing the structural unit represented by the general formula (II) is 1 to 30% by mass, A polycarbonate-polyorganosiloxane copolymer having a viscosity average molecular weight of 13,000 to 26,000.

In the polycarbonate resin composition of the present invention, there are various dihydric phenols represented by the general formula (1) used as a raw material for the polycarbonate-polyorganosiloxane copolymer (A-1). 2,2-bis (4-hydroxyphenyl) propane [common name: bisphenol A] is preferred.
Examples of bisphenols other than bisphenol A include bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, and 2,2-bis. (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) ) Naphthylmethane, 1,1-bis (4-hydroxy-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3, 5-tetramethylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophene) Bis (hydroxyaryl) alkanes such as propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,5,5-trimethylcyclohexane, 2, Bis (hydroxyaryl) cycloalkanes such as 2-bis (4-hydroxyphenyl) norbornane and 1,1-bis (4-hydroxyphenyl) cyclododecane, 4,4′-dihydroxyphenyl ether, 4,4′-dihydroxy Dihydroxy aryl ethers such as 3,3′-dimethylphenyl ether, 4,4′-di Droxydiphenyl sulfide, dihydroxydiaryl sulfides such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide, 4,4′-dihydroxydiphenyl sulfoxide, 4,4′-dihydroxy-3,3′-dimethyldiphenyl Dihydroxy diaryl sulfoxides such as sulfoxide, 4,4′-dihydroxydiphenyl sulfone, dihydroxy diaryl sulfones such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone, dihydroxy such as 4,4′-dihydroxydiphenyl Dihydroxy diarylfluorenes such as diphenyls, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, bis (4-hydroxyphenyl) dipheny Dihydroxydiaryl such as methane, 1,3-bis (4-hydroxyphenyl) adamantane, 2,2-bis (4-hydroxyphenyl) adamantane, 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane Adamantanes, 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol, 10,10-bis (4-hydroxyphenyl) -9-anthrone, 1,5-bis (4-hydroxyphenyl) Thio) -2,3-dioxapentaene and the like.
These dihydric phenols may be used alone or in combination of two or more.

  When the polyorganosiloxane represented by the general formula (2) is exemplified, for example,

[In the general formulas (3) to (11), R ³ , R ⁴ , R ⁵ and R ⁶ may each independently have a hydrogen atom, a halogen atom or a substituent, as in the general formula (1). Represents a good alkyl group or aryl group, R ⁸ represents an alkyl, alkenyl, aryl or aralkyl group, n represents an integer of 70 to 1,000 in terms of the average number of repeating units of the organosiloxane constituent unit, and c represents a positive integer . ]
Etc.
Among these, the phenol-modified polyorganosiloxane represented by the formula (3) is preferable from the viewpoint of easy polymerization, and α, ω-bis [3- (o-hydroxyphenyl), which is one of the compounds represented by the formula (4). ) Propyl] polydimethylsiloxane, or α, ω-bis [3- (4-hydroxy-3-methoxyphenyl) propyl] polydimethylsiloxane, which is one of the compounds represented by formula (5), is preferable because of its availability. .

  The polyorganosiloxane represented by the general formula (2) is a phenol having an olefinically unsaturated carbon-carbon bond, preferably vinylphenol, allylphenol, eugenol, isopropenylphenol or the like having a predetermined polymerization degree n. It can be easily produced by hydrosilation reaction at the end of the polyorganosiloxane chain.

In the polycarbonate resin composition of the present invention, the aromatic polycarbonate (A-2) other than (A-1) is reacted with a dihydric phenol compound and phosgene in the presence of an organic solvent inert to the reaction and an aqueous alkaline solution. After that, an interfacial polymerization method in which a polymerization catalyst such as a tertiary amine or a quaternary ammonium salt is added for polymerization, or a dihydric phenol compound is dissolved in pyridine or a mixed solution of pyridine and an inert solvent, and phosgene is dissolved. Those obtained by a conventional method for producing an aromatic polycarbonate such as a pyridine method for direct production by introduction are used.
In the above reaction, a terminal terminator, a molecular weight regulator, a branching agent and the like are used as necessary.

Examples of the dihydric phenol compound used for the production of the aromatic polycarbonate (A-2) include 2,2-bis (4-hydroxyphenyl) propane [= bisphenol A], bis (4-hydroxyphenyl) methane, 1 , 1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, bis ( 4-hydroxyphenyl) diphenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) naphthylmethane, 1,1-bis (4-hydroxy-3-tert-butylphenyl) ) Propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis ( 4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2 -Bis (hydroxyaryl) alkanes such as bis (4-hydroxy-3,5-dibromophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) Cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,5,5-trimethylcyclohexane, 2,2-bis (4-hydroxyphenyl) norbornane, 1,1-bis (4-hydroxyphenyl) cyclododecane, etc. Bis (hydroxyaryl) cycloalkanes, 4,4′-dihydroxyphenyl ether, 4,4 Dihydroxyaryl ethers such as'-dihydroxy-3,3'-dimethylphenyl ether, dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, Dihydroxydiaryl sulfoxides such as 4,4′-dihydroxydiphenyl sulfoxide, 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide, 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxy-3,3 Dihydroxy diaryl sulfones such as' -dimethyldiphenyl sulfone, dihydroxy diphenyls such as 4,4'-dihydroxydiphenyl, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3 -Methylfe D) Dihydroxydiarylfluorenes such as fluorene, bis (4-hydroxyphenyl) diphenylmethane, 1,3-bis (4-hydroxyphenyl) adamantane, 2,2-bis (4-hydroxyphenyl) adamantane, 1,3-bis Dihydroxydiaryladamantanes such as (4-hydroxyphenyl) -5,7-dimethyladamantane, 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol, 10,10-bis (4-hydroxy) Phenyl) -9-anthrone, 1,5-bis (4-hydroxyphenylthio) -2,3-dioxapentaene, and the like.
These dihydric phenols may be used alone or in combination of two or more.

In the production of the aromatic polycarbonate (A-2), a terminal terminator or a molecular weight regulator is usually used.
As the molecular weight regulator, various types can be used as long as they are usually used for polymerization of polycarbonate resin.
Specifically, as monohydric phenol, for example, phenol, on-butylphenol, mn-butylphenol, pn-butylphenol, o-isobutylphenol, m-isobutylphenol, p-isobutylphenol, ot -Butylphenol, mt-butylphenol, pt-butylphenol, on-pentylphenol, mn-pentylphenol, pn-pentylphenol, on-hexylphenol, mn-hexylphenol, pn-hexylphenol, pt-octylphenol, o-cyclohexylphenol, m-cyclohexylphenol, p-cyclohexylphenol, o-phenylphenol, m-phenylphenol, p-phenylphenol, on-nonylphenol M-nonylphenol, pn-nonylphenol, o-cumylphenol, m-cumylphenol, p-cumylphenol, o-naphthylphenol, m-naphthylphenol, p-naphthylphenol, 2,5-di -T-butylphenol, 2,4-di-t-butylphenol, 3,5-di-t-butylphenol, 2,5-dicumylphenol, 3,5-dicumylphenol, p-cresol, bromophenol, tribromo Phenol, monoalkylphenol having a linear or branched alkyl group having an average carbon number of 12 to 35 at the ortho, meta or para position, 9- (4-hydroxyphenyl) -9- (4-methoxyphenyl) fluorene 9- (4-Hydroxy-3-methylphenyl) -9- (4-methoxy-3-methylphenyl) Le) fluorene, 4- (1-adamantyl) phenol and the like.
Among these monohydric phenols, pt-butylphenol, p-cumylphenol, p-phenylphenol and the like are preferably used.
Of course, two or more compounds may be used in combination.
Furthermore, it is possible to obtain a branched polycarbonate by using a branching agent in combination in the range of 0.01 to 3 mol%, particularly 0.1 to 1.0 mol% with respect to the dihydric phenol compound. Examples of branching agents include 1,1,1-tris (4-hydroxyphenyl) ethane, 4,4 ′-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene. ] Bisphenol, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, 1- [α-methyl-α- (4′-hydroxyphenyl) ethyl] -4- A compound having three or more functional groups such as [α ′, α′-bis (4 ″ -hydroxyphenyl) ethyl] benzene, phloroglysin, trimellitic acid, and isatin bis (o-cresol) can be used.

  In the polycarbonate resin composition used in the present invention, conventionally, various known additives can be blended in the polycarbonate resin composition as desired, and these include reinforcing materials, fillers, stabilizers, antioxidants. UV absorbers, antistatic agents, lubricants, mold release agents, dyes, pigments, other flame retardants, and elastomers for improving impact resistance.

The polycarbonate resin composition used in the present invention can be obtained by blending and kneading the components (A-1) and (A-2) and, if necessary, known additives.
The blending and kneading are usually performed using a method such as a ribbon blender, a Henschel mixer, a Banbury mixer, a drum tumbler, a single screw extruder, a twin screw extruder, a kneader, or a multi screw extruder. It can be done by a method.
The heating temperature for kneading is usually selected in the range of 250 to 320 ° C.

For molding the obtained polycarbonate resin composition, various conventionally known molding methods such as injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, foam molding, etc. However, it is preferable to perform injection molding at a mold temperature of 60 ° C. or higher, preferably 80 to 120 ° C.
Under the present circumstances, the resin temperature in injection molding is about 280-360 degreeC normally, Preferably it is 280-330 degreeC.
As an injection molding method, gas injection molding can be employed for preventing the appearance of sink marks or reducing the weight.

The wall thickness of the portable electronic device casing obtained by molding the polycarbonate resin composition containing the polycarbonate-polyorganosiloxane copolymer having a specific structure of the present invention is 0.5 to 1.5 mm, preferably 0. .6 to 1.4 mm, more preferably 0.6 to 1.3 mm.
The portable electronic device casing of the present invention can be used for portable electronic devices such as a portable personal computer, a personal digital assistant (PDA), a cellular phone, a portable player, and a battery case. preferable.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples.

[Production Example 1 of Polycarbonate-Polydimethylsiloxane Copolymer (PC / PDMS Copolymer)]
Polycarbonate oligomer production 2,000 ppm sodium dithionite was added to 5.6 mass% sodium hydroxide aqueous solution to bisphenol A (BPA) to be dissolved later, and BPA concentration was adjusted to 13.5 mass%. And an aqueous sodium hydroxide solution of BPA was prepared.
Phosgene was continuously passed through a tubular reactor having an inner diameter of 6 mm and a tube length of 30 m at a flow rate of 4.0 kg / hr at a flow rate of 40 liter / hr of sodium hydroxide aqueous solution of BPA and 15 liter / hr of methylene chloride.
The tubular reactor had a jacket portion, and the temperature of the reaction solution was kept at 40 ° C. or lower by passing cooling water through the jacket.
The reaction liquid exiting the tubular reactor was continuously introduced into a baffled tank reactor having an internal volume of 40 liters equipped with a receding blade, and further 2.8 liters / hr of sodium hydroxide aqueous solution of BPA, 25 The reaction was carried out by adding 0.07 liter / hr of a mass% aqueous sodium hydroxide solution, 17 liter / hr of water, and 0.64 liter / hr of a 1 mass% triethylamine aqueous solution.
The reaction liquid overflowing from the tank reactor was continuously extracted and allowed to stand to separate and remove the aqueous phase, and the methylene chloride phase was collected.
The polycarbonate oligomer thus obtained had a concentration of 329 g / L and a chloroformate group concentration of 0.74 mol / L.

Production of polycarbonate-polydimethylsiloxane copolymer 15 L of polycarbonate oligomer solution produced above in a 50 L tank reactor equipped with baffle plate, paddle type stirring blade and cooling jacket, 9.0 L of methylene chloride, repeated dimethylsiloxane units Charge 343 g of allylphenol-terminated polydimethylsiloxane (PDMS) having a number of 90 and 8.8 mL of triethylamine, add 1389 g of 6.4% by weight aqueous sodium hydroxide solution with stirring, and add polycarbonate oligomer and allylphenol end for 10 minutes. A modified PDMS reaction was performed.
To this polymerization liquid, methylene chloride solution of pt-butylphenol (PTBP) (126 g of PTBP dissolved in 2.0 L of methylene chloride), BPA sodium hydroxide aqueous solution (577 g of NaOH and 2.0 g of sodium dithionite) in water A solution obtained by dissolving 1012 g of BPA in an aqueous solution dissolved in 8.4 L) was added, and a polymerization reaction was carried out for 50 minutes.
For dilution, 10 L of methylene chloride was added and stirred for 10 minutes. Then, the organic phase was separated into an organic phase containing a polycarbonate-polydimethylsiloxane copolymer and an aqueous phase containing excess BPA and NaOH, and the organic phase was isolated.
The methylene chloride solution of the polycarbonate-polydimethylsiloxane copolymer thus obtained was washed successively with 15% by volume of 0.03 mol / L NaOH aqueous solution and 0.2 mol / L hydrochloric acid with respect to the solution. Washing with pure water was repeated until the electrical conductivity in the aqueous phase became 0.01 μS / m or less.
The methylene chloride solution of the polycarbonate-polydimethylsiloxane copolymer obtained by washing was concentrated and pulverized, and the obtained flakes were dried at 120 ° C. under reduced pressure.
The amount of PDMS residue (PDMS copolymerization amount) determined by nuclear magnetic resonance (NMR) of the obtained polycarbonate-polydimethylsiloxane copolymer was 5.6% by mass and measured in accordance with ISO 1628-4 (1999). The viscosity number was 51.2 and the viscosity average molecular weight Mv = 19300.

[Production Examples 2 to 9 of Polycarbonate-Polydimethylsiloxane Copolymer (PC / PDMS Copolymer)]
Table 1 shows the types of terminal-modified PDMS (allylphenol terminal-modified PDMS or eugenol terminal-modified PDMS), the number of dimethylsiloxane units repeated, the amount of terminal-modified PDMS used, and the amount of PTBP used. A copolymer was produced.
Table 1 shows the PDMS residue amount (PDMS copolymerization amount), viscosity number, and viscosity average molecular weight Mv of the obtained polycarbonate-polydimethylsiloxane copolymer.

Examples 1-7 and Comparative Examples 1-3
Polycarbonate-polydimethylsiloxane copolymer (PC / PDMS copolymer) produced in Production Examples 1 to 9, FN1500 (trade name, manufactured by Idemitsu Kosan Co., Ltd., BPA polycarbonate having pt-butylphenol as a terminal group, Viscosity 39.2, viscosity average molecular weight Mv = 14500), Taflon FN1700A (trade name, manufactured by Idemitsu Kosan Co., Ltd., BPA polycarbonate having pt-butylphenol as a terminal group, viscosity number 47.1, viscosity average molecular weight Mv = 17500), Taflon FN2700A (trade name, manufactured by Idemitsu Kosan Co., Ltd., BPA polycarbonate having pt-butylphenol as a terminal group, viscosity number 69.6, viscosity average molecular weight Mv = 27500), IRGAFOS168 (trade name, ( (Made by ADEKA Co., Ltd.) Using a single screw extruder equipped with a vent 40 mm diameter, to obtain a granulated and pelletized at a resin temperature of 280 ° C..
In Comparative Example 3 only, the resin temperature was 300 ° C.

The obtained pellets were dried at 120 ° C. for 8 hours and then injection molded at a molding temperature of 280 ° C. and a mold temperature of 80 ° C. using an injection molding machine to obtain test pieces.
The following measurements were performed using pellets or test pieces obtained by injection molding.
The results are shown in Table 2.
(1) Melt flowability MFR (melt flow rate)
Based on JIS K7210, the amount of molten resin (g / 10 minutes) flowing out from a die having a diameter of 2 mm and a length of 8 mm was measured under a load of 280 ° C. and 2.16 kg.
(2) Q value (flow value) [unit: 10 ^-2 ml / sec]
Using an elevated flow tester, the amount (mL / sec) of molten resin flowing out from a nozzle having a diameter of 1 mm and a length of 10 mm was measured under a pressure of 280 ° C. and 15.7 MPa based on JIS K7210.
The Q value represents the amount of outflow per unit time, and the higher the value, the better the fluidity.
(3) HDT (thermal deformation temperature)
Measurement was performed at a load of 0.45 MPa in accordance with ASTM D648.
HDT is a measure of heat resistance.

[Molding mobile phone model]
Using the pellets obtained above, a molded article (50 mm × 88 mm, depth 4.5 mm, thickness 1.2 mm) shown in the dimension explanatory diagram of FIG. 1 was obtained by injection molding under the following conditions.
In Comparative Example 3, injection molding was attempted, but at a cylinder temperature of 300 to 320 ° C., the viscosity was high, filling was impossible, and a molded product could not be obtained.
Further, the molding was attempted by raising the cylinder temperature to 360 ° C., but a molded product could not be obtained, and when the cylinder temperature was raised to 380 ° C., the molding was stopped because coloring due to deterioration of the resin composition began to appear. .
Molding conditions Injection molding machine: Nissei Plastic Industrial Co., Ltd. Electric injection molding machine ES-1000 80 tons Molding machine cylinder temperature: 300-320 ° C
Molding cycle: 30 seconds / cycle
Mold temperature: 130 ° C
(Drop impact resistance evaluation)
The obtained molded product was put into a thermostat and cooled to a predetermined temperature (0 ° C., −10 ° C., −20 ° C.).
Two hours later, the molded article was taken out from the thermostatic chamber, and immediately after dropping a weight of 1280 g onto the molded article from a height of 1.85 m, the drop impact resistance was evaluated.
The same test was performed 5 times, and Table 2 shows the presence or absence of cracks, the presence or absence of cracks, and the types of cracks (ductile cracks and brittle cracks).
The case where the fracture surface (fracture surface) was ductile was evaluated as ductile cracking, and the case where the fracture surface was brittle was evaluated as brittle cracking.
In addition, a numerical value shows the presence or absence of the crack in five tests, the presence or absence of crack generation, and the number of types of cracks, and the total is 5.

  ADVANTAGE OF THE INVENTION According to this invention, the portable electronic device housing | casing which is thin and excellent in drop impact resistance, fluidity | liquidity, and heat resistance can be provided.

Claims (4)

The content of the polyorganosiloxane block part having the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II) and including the structural unit represented by the general formula (II) is A polycarbonate-polyorganosiloxane copolymer (A-) having an average number of repeating units of 70 to 1000 and a viscosity average molecular weight of 13,000 to 26000 in the structural unit of the general formula (II) is 1 to 30% by mass. 1) Molding a polycarbonate resin composition containing 10 to 100 parts by mass and 0 to 90 parts by mass of an aromatic polycarbonate (A-2) other than (A-1) so that the total amount becomes 100 parts by mass. A portable electronic device casing.

[Wherein, R ¹ and R ² are each independently an alkyl group or alkoxy group having 1 to 6 carbon atoms, X is a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, carbon A cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, —S—, —SO—, —SO ₂ —, —O— or —CO—, R ³ and R ⁴ are each independently , A hydrogen atom, a halogen atom or an optionally substituted alkyl group or aryl group, a and b each independently represent an integer of 0 to 4. ]   The portable electronic device casing according to claim 1, wherein the casing is molded by injection molding.   The portable electronic device casing according to claim 2, wherein the thickness of the portable electronic device casing is 0.5 to 1.5 mm.   The portable electronic device casing according to claim 2 or 3, wherein the portable electronic device of the portable electronic device casing is a mobile phone.

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