JP2002053747A - Polycarbonate resin composition and part for conveying electrical/electronic part composed of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition excellent in mechanical strength, heat resistance and electrical characteristics such as electroconductivity, antistaticity and the like, and hardly stained by a volatile substance. SOLUTION: The polycarbonate resin composition comprises a polycarbonate resin and an electroconductive substance in a weight ratio of 70/30-99.9/0.1 and contains 20 ppm or less of volatile substances in terms of heptane as measured using the head space gas chromatography under a condition of 100 deg.C for 30 min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polycarbonate resin composition and, more particularly, to a polycarbonate resin composition suitable for electric / electronic part conveying parts and an electric / electronic part conveying part comprising the same.

[0002]

2. Description of the Related Art In recent years, OA equipment and electronic equipment have become smaller, lighter, more highly integrated, and more precise, and accordingly, various and stricter requirements have been increasing. There is a demand for reducing dust adhesion as much as possible. These electric and electronic components cause problems such as defective contacts and reading errors if dust and dust adhere to them.
Originally, they hate the adhesion of dust and dust, but their requirements have become more stringent due to their small size, light weight, high integration, and high precision. For example, an IC chip used for a semiconductor, a wafer, and internal components of a hard disk used for a computer are the best examples.

Usually, the manufacture and assembly of these parts are performed in a so-called clean room where the amount of dust and dust is extremely small, and the adhesion of dust and dust does not occur here. , The adhesion here becomes a problem. Parts for transporting these electric and electronic parts (tray, case, housing, etc.)
In many cases, synthetic resin is used in terms of design and weight reduction, and among them, polycarbonate resin is excellent in mechanical strength, heat resistance, and dimensional stability, so it is a resin suitable for this application. .

However, polycarbonate resins are:
Because it is an insulating material that does not conduct electricity, it is easily charged,
Dust and dust easily adhere. For this reason, there is a problem in that the dust and dust adhering to the parts for conveyance adhere to the main body of the electric and electronic parts during the conveyance. In order to prevent this, polycarbonate resin used for transport parts includes
For example, carbon black, carbon fiber, or the like is blended in order to lower the electric resistance and impart conductivity.

[0005] Except for the problem of adhesion of dust and dust, chlorine compounds typified by carbon tetrachloride can corrode electric and electronic parts and cause malfunctions. The gazette discloses that a polycarbonate resin having a small amount of volatile chlorine is used as a material resin of the precision member storage container. However, it has been difficult to obtain a polycarbonate resin composition which does not adversely affect electric and electronic parts and has no problem of adhesion of dust and dust by using only such a polycarbonate resin.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polycarbonate resin composition which is excellent in electrical properties such as mechanical strength, heat resistance, conductivity and antistatic properties, and which is less contaminated by volatile substances. It is another object of the present invention to provide a component for transporting electric and electronic components.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the present invention is that the weight ratio of a polycarbonate resin to a conductive material is 70/30.
９９99.9 / 0.1, and the amount of volatile components is 20 ppm or less in terms of heptane measured at 100 ° C. × 30 min using a headspace gas chromatograph.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. As the polycarbonate resin in the present invention, aromatic polycarbonates, aliphatic polycarbonates, and aromatic-aliphatic polycarbonates can be used, and among them, aromatic polycarbonates are preferable. The aromatic polycarbonate resin may be an aromatic hydroxy compound or a thermoplastic aromatic polycarbonate polymer or copolymer which may be branched by reacting a small amount of the polyhydroxy compound with phosgene or a carbonic acid diester. is there.

The aromatic dihydroxy compounds include 2,2.
2-bis (4-hydroxyphenyl) propane (= bisphenol A), tetramethylbisphenol A, bis (4-hydroxyphenyl) -P-diisopropylbenzene, hydroquinone, resorcinol, 4,4-dihydroxydiphenyl, and the like, Preferably, bisphenol A is used. Furthermore, for the purpose of further increasing the flame retardancy, a compound in which at least one tetraalkylphosphonium sulfonate is bonded to the aromatic dihydroxy compound and / or a polymer or oligomer having a phenolic OH group at both ends and having a siloxane structure is used. Can be.

In order to obtain a branched aromatic polycarbonate resin, phloroglucin, 4,6-dimethyl-2,4,4
6-tri (4-hydroxyphenyl) heptene-2,
4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptane, 2,6-dimethyl-2,4,6-
Tri (4-hydroxyphenylheptene-3,1,3,
5-tri (4-hydroxyphenyl) benzene, 1,
Polyhydroxy compounds represented by 1,1-tri (4-hydroxyphenyl) ethane or the like; 3,3-bis (4-hydroxyaryl) oxindole (= isatin bisphenol); 5-chlorisatin bisphenol; 7-dichlorisatin bisphenol, 5-
Bromoisatin bisphenol or the like may be used as part of the aromatic dihydroxy compound, and the amount used is
It is about 0.01 to 10 mol%, preferably 0.1 to
It is about 2 mol%.

In order to control the molecular weight, a monovalent aromatic hydroxy compound may be used, and m- and p-methylphenol, m- and p-propylphenol, p-tert-
Butylphenol and p-long-chain alkyl-substituted phenols. The aromatic polycarbonate resin used in the present invention is preferably a polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane, or 2,2-bis (4-hydroxyphenyl) propane and another aromatic dihydroxy resin. And a polycarbonate copolymer derived from the compound. Further, two or more kinds of polycarbonate resins can be used in combination.

The viscosity average molecular weight of the polycarbonate resin is determined by using methylene chloride as a solvent at a temperature of 25 ° C.
It is a value calculated from the solution viscosity measured in the above.
4,000 to 30,000. Viscosity average molecular weight of 1
If it is less than 4,000, the mechanical strength is insufficient, and
If it exceeds 00, the moldability is insufficient. The viscosity average molecular weight of the polycarbonate resin is more preferably 15,000.
0-28,000, most preferably 16,000
~ 26,000.

The method for producing the aromatic polycarbonate resin is not limited, and it can be produced by a phosgene method (interfacial polymerization method) or a melting method (ester exchange method). Further, an aromatic polycarbonate resin produced by a melting method and having an adjusted amount of terminal OH groups can be used.

The conductive substance in the present invention is a substance that conducts electricity, and examples thereof include a conductive organic substance and a conductive inorganic substance. Examples of the conductive substance include ionic organic surfactants, nonionic organic surfactants, polymer antistatic agents having a polyethylene glycol unit, polymer antistatic agents having an ionic functional group, carbon black, carbon fiber , Graphite, carbon whiskers, hollow carbon fibrils, metal fibers, metal powders, metal oxides and the like. As the conductive substance, a conductive inorganic substance is preferable because the generation of the volatile substance due to the attachment of the volatile substance and the decomposition of the polycarbonate is small. As the conductive inorganic substance, preferably, a carbon fiber, a hollow carbon fibril, or the like is used, and a hollow carbon fibril is particularly preferable because conductivity can be imparted in a small amount.

[0015] Hollow carbon fibrils are carbon fibrils having a hollow structure. The outer diameter of hollow carbon fibrils is
The number average is preferably 3 to 70 nm. If the fibril outer diameter is less than 3 nm, dispersibility in the resin tends to be insufficient, and if it exceeds 70 nm, the conductivity of the obtained resin composition tends to be insufficient. The outer diameter of the hollow carbon fibrils is, on average, more preferably 4 to 60 nm. The aspect ratio of hollow carbon fibrils is number average,
Preferably it is 5 or more. When the aspect ratio is less than 5, the conductivity of the obtained resin composition tends to be insufficient. The aspect ratio of hollow carbon fibrils is number average,
More preferably, it is 7 or more. The measurement of the outer diameter and the aspect ratio of the hollow carbon fibrils can be performed by observing the hollow carbon fibrils with an electron microscope and analyzing the obtained photograph by image analysis.

A hollow carbon fibril has an outer region consisting of an essentially continuous multi-layer of regularly arranged carbon atoms and an inner hollow region, each layer and hollow region being defined by the cylindrical axis of the fibril. An essentially cylindrical fibril disposed substantially concentrically around the periphery. Further, it is preferable that the regularly arranged carbon atoms in the outer region are in the form of graphite, and the diameter of the hollow region is 2 to 20 nm.

For hollow carbon fibrils, for example,
JP-T-62-500943 and U.S. Pat.
No. 3,230. As for the production method, as described in the above-mentioned patent gazettes and U.S. patent specifications, for example, iron, cobalt with alumina as a support,
A transition metal-containing particle such as a nickel-containing particle is brought into contact with a carbon-containing gas such as carbon monoxide or a hydrocarbon at a high temperature of 850 to 1200 ° C., and carbon generated by thermal decomposition is grown into a fibrous form starting from the transition metal. Method. The hollow carbon fibrils are commercially available from Hyperion Catalysis under the trade name "Graphite Fibrils".

The weight ratio between the polycarbonate resin and the conductive substance is from 70/30 to 99.9 / 0.1. If the weight ratio between the polycarbonate resin and the conductive substance is less than 70/30, the mechanical strength is insufficient, and 99.9 / 0.1
If it exceeds, conductivity and antistatic performance are insufficient. The weight ratio between the polycarbonate resin and the conductive substance is preferably from 75/25 to 99.5 / 0.5, and more preferably from 80/20 to 99.2 / 0.8.

The polycarbonate resin composition of the present invention may contain, if necessary, stabilizers such as ultraviolet absorbers and antioxidants, additives such as pigments, dyes, lubricants, flame retardants, mold release agents, glass fibers, A reinforcing material such as glass flake, talc, mica, potassium titanate, aluminum borate, wollastonite, or a thermoplastic resin other than a polycarbonate resin can be added and blended. As the thermoplastic resin other than the polycarbonate resin, polyester, polyamide, H
Styrene resins such as IPS or ABS, and thermoplastic resins such as polyolefins are exemplified. The blending amount of the thermoplastic resin other than the polycarbonate resin is preferably 40% by weight or less, more preferably 30% by weight or less based on all resin components. In the polycarbonate resin composition of the present invention,
Elastomers commonly used as impact modifiers can also be added.

As a method for obtaining the polycarbonate resin composition of the present invention, the above-mentioned components are kneaded with various kneaders, for example, a single-shaft or multi-shaft kneader, a Banbury mixer, a roll, a Brabender plastogram, and then cooled and solidified. And a suitable solvent, for example, hexane, heptane,
A solution mixing method is used in which the above components are added to hydrocarbons such as benzene, toluene, xylene, and derivatives thereof, and the dissolved components are mixed together, or the dissolved and insoluble components are mixed in a suspended state. The melt-kneading method is preferred from the industrial cost, but is not limited thereto.

The amount of volatile components of the polycarbonate resin composition of the present invention is 20 parts in terms of heptane measured at 100 ° C. × 30 minutes using a head space gas chromatograph.
ppm or less. When the volatile content exceeds 20 ppm,
Problems occur due to surface contamination of IC chips, wafers, and hard disks, which adversely affect electric and electronic components. The volatile matter content of the polycarbonate resin composition is preferably 15
ppm or less, more preferably 10 ppm or less.

For measurement using a head space gas chromatograph, the head space is set at 100 ° C., a sample is introduced into a sample tube for 30 minutes, and the generated volatiles are adsorbed. Next, the adsorbed volatile substance is introduced into a gas chromatograph to obtain a chromatogram. Here, volatile substances generated from the sample are quantified based on a heptane calibration curve separately measured and prepared. In addition, qualitative analysis can be performed on substances whose retention time is known in the gas chromatogram.

In the present invention, any method may be used as a method for reducing the volatile content, and is not particularly limited, but a method for reducing the volatile content in the polycarbonate resin before melt-kneading, melt-kneading, And the like to remove volatile components. In order to reduce the volatile components in the polycarbonate before melt-kneading, a method of increasing the drying temperature, a method of extending the drying time, and the like can be mentioned. Specifically, it is preferable to use a polycarbonate resin having a volatile content of 300 ppm or less in terms of heptane measured at 100 ° C. × 30 min using the above headspace gas chromatograph for melt kneading.

In order to remove volatile components during melt kneading, it is preferable to enhance the degassing performed during melt kneading. The degree of pressure reduction during degassing is preferably 15 torr or less, more preferably 10 torr or less, and most preferably 5 torr or less.
orr or less. Alternatively, 0.1 to 5 parts by weight of water may be added and melt-kneaded to azeotrope with volatile components.

The electric / electronic part conveying part of the present invention can be obtained by molding using the above polycarbonate resin composition. The molding method is not particularly limited, and a molding method generally used for a thermoplastic resin composition, for example, injection molding, hollow molding, extrusion molding, sheet molding, thermoforming, rotational molding, lamination molding, and the like Can be applied.

The components for transporting electric / electronic components according to the present invention include, for example, trays for IC chips and IC component boxes, trays and cases for wafers, storage boxes and trays for circuit boards, optical disks such as hard disks, CDs, DVDs and MOs. And trays and storage boxes for components such as a base of a magnetic recording medium, a housing, a head, and the like. Electrical and electronic parts transport parts are required to have low surface resistance because they do not like the adhesion of dust and dust. However, if the parts are too low, there is a risk of short-circuit, which is not preferable. The surface resistance value of the electric / electronic component conveying component is preferably 10 ³ to 10 ¹² Ω, and more preferably 10 ³ to 10 ¹⁰ Ω.

Electrical and electronic parts transporting parts are required to have antistatic performance in order to prevent adhesion of dust and dust. Here, the antistatic performance can be evaluated by measuring the relative charge value using a static honest meter. The relative charging value is an index indicating the difficulty of charging, and is preferably small, specifically, 5 mV or less when a voltage of 10 kV is applied, and more preferably 2 mV or less. .

[0028]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which, however, are not intended to limit the scope of the invention. In the following examples, the following components were used as each component. (A) Polycarbonate 1: 3.7k of sodium hydroxide
g was dissolved in 42 L of water and kept at 20 ° C.
7 kg of bis (4-hydroxyphenyl) propane and 15 g of hydrosulfide were dissolved. To this, 30 L of methylene chloride was added, and while stirring, 148 g of pt-butylphenol was added.
I blew it in 0 minutes. After the phosgene blowing was completed, the reaction solution was vigorously stirred to emulsify the reaction solution. After the emulsification, 8 mL of triethylamine was added, and stirring was continued for about 1 hour to carry out polymerization. After separating the polymerization liquid into an aqueous phase and an organic phase and neutralizing the organic phase with phosphoric acid,
After the washing was repeated until the pH of the washing became neutral, 35 L of isopropanol was added to precipitate a polymer. After filtering the precipitate, the precipitate was washed with 35 L of heptane and filtered. Thereafter, the resultant was dried at 120 ° C. for 7 hours to obtain a white powdery polycarbonate. The volatile content of the obtained polycarbonate was measured at 100 ° C. for 30 minutes using a headspace gas chromatograph. As a result, the volatile content in terms of heptane was 100 ppm, and the viscosity average molecular weight was 21,000.

(B) polycarbonate 2: drying time is 1
Except for 2 hours at 20 ° C., the above polycarbonate 1
A white powdered polycarbonate was obtained in the same manner as described above. The volatile content of the obtained polycarbonate was measured at 100 ° C. for 30 minutes using a headspace gas chromatograph. As a result, the volatile content in terms of heptane was 700 ppm, and the viscosity average molecular weight was 21,000.

(C) Hollow carbon fibril masterbatch: Master pellet consisting of 15% by weight of hollow carbon fibrils and 85% by weight of polycarbonate, manufactured by Hyperion International, trade name: PC / 15BN. The outer diameter of the hollow carbon fibrils was 10 nm in number average, and the aspect ratio was 500 in number average. (D) Carbon fiber: a product of Toho Rayon Co., Ltd., trade name: Vesfight C6-SR.

The evaluation method is as follows. (1) Flexural modulus: A three-point bending test was performed according to a bending test method according to ASTM D790. (2) Deflection temperature under load: According to ASTM D648,
A load deflection test was performed under the condition of 1.82 MPa. (3) Surface resistance: A square plate molded product of 50 mm × 90 mm × 3.2 mmt was measured with a Loresta or Hiresta manufactured by Mitsubishi Chemical Corporation. (A high resta was used for a value of 10 ⁴ Ω or more, and a loresta was used for a value less than 10 ⁴ Ω.)

(4) Antistatic performance: 50 mm × 90 mm
Using a square plate molded product of × 3.2 mmt, the relative charging value was measured. The relative charging value was measured using a static honest meter under the conditions of an imprint voltage of 10 kV and an imprint time of 1 minute. (5) Amount of volatiles: 1.5 g of pellets were set in a sample tube of a head space device (JHS-100A, manufactured by Nippon Kagaku Kogyo Co., Ltd.), allowed to stand at 100 ° C. for 30 minutes, and a volatile gas adsorption tube using He as a carrier gas. Was adsorbed. The adsorbed volatiles are analyzed by gas chromatography (HP5, manufactured by Yokogawa).
890A), and He is used as a carrier gas.
The temperature is raised from 0 ° C to 300 ° C at a rate of 10 ° C / min.
Detected. Based on the obtained gas chromatogram and a previously prepared calibration curve for heptane, the amount of heptane-converted volatiles was determined.

Example 1 Raw materials prepared so that the weight ratio of polycarbonate 1 to hollow carbon fibril masterbatch was 90/10 were uniformly mixed with a tumbler mixer, and then mixed with a twin-screw extruder (30 mmφ). The mixture was pelletized at a cylinder temperature of 300 ° C. and a vent pressure of 15 torr. The pellets were injection-molded using an injection molding machine (Sumitomo Nestal's product, mold clamping force 75T) under the conditions of a cylinder temperature of 280 ° C and a mold temperature of 80 ° C to produce molded articles, and various evaluations were made. [Example 2] Pelletization was performed in the same manner as in Example 1 except that the degree of vent pressure reduction was changed to 4 torr, and a molded product was prepared and various evaluations were performed.

Example 3 A pellet was formed in the same manner as in Example 2 except that polycarbonate 2 was used instead of polycarbonate 1, and a molded article was prepared and various evaluations were made. Example 4 Polycarbonate 1 was added at a ratio such that the weight ratio of polycarbonate 1 to carbon fiber was 85/15.
Is supplied at a cylinder temperature of 300 ° C. using a twin-screw extruder (30 mmφ), and while the carbon fiber is fed from a feed port provided downstream, the vent pressure is reduced to 15 torr.
And pelletized. The obtained pellets were injection-molded in the same manner as in Example 1 to form molded articles and various evaluations were performed. Example 5 Pelletization was performed in the same manner as in Example 4 except that the degree of vent pressure reduction was changed to 4 torr, and a molded article was prepared and various evaluations were performed.

Example 6 The pellets obtained in Example 1 were molded to prepare a hard disk substrate transport / storage container. The hard disk substrate was stored in the obtained container, left at 23 ° C. for 168 hours, the hard disk substrate was taken out, the surface of the hard disk substrate was washed with acetone, and the recovered acetone washing solution was measured by gas chromatography. No organic matter was detected. From this, the hard disk substrate surface was normal without being contaminated. The surface resistance of the obtained container was 4 ×
10 ⁶ Ω.

[0036]

[Table 1]

[Comparative Example 1] The pressure of the vent was reduced to 600 ton.
Pelletization was performed in the same manner as in Example 1 except that rr was changed, and a molded body was prepared and various evaluations were performed. [Comparative Example 2] Pelletization was performed in the same manner as in Example 4 except that polycarbonate 2 was used as the polycarbonate, and a molded article was prepared and various evaluations were performed. [Comparative Example 3] Pelletization was performed in the same manner as in Example 1 except that the conductive material was not added, and a molded body was formed.
Various evaluations were made.

[0038]

[Table 2]

[0039]

Industrial Applicability The polycarbonate resin composition of the present invention is excellent in electrical properties such as mechanical strength, heat resistance, conductivity and antistatic properties, and has extremely low pollution by volatile substances, and is suitable for electric and electronic parts. Suitable for materials of parts for transportation.
The component for transporting electric and electronic components of the present invention has extremely low contamination to the surface of an IC chip, a wafer, or a hard disk, does not easily cause trouble due to dirt, and has a mechanical strength,
It has excellent heat resistance, conductivity, and antistatic properties, and its industrial utility is extremely large.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Naoto Obayashi 5-6-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa F-term in the Engineering Center of Mitsubishi Engineering-Plastics Corporation (reference) 3E096 BA08 CA01 EA02X FA03 FA07 FA07 FA20 GA01 4J002 CG001 DA016 DA026 DA036 DA066 DE046 FA016 FA066 FD106 FD116 FD316 GQ00

Claims (9)

[Claims] 1. A weight ratio of a polycarbonate resin to a conductive substance is 70/30 to 99.9 / 0.1, and a volatile content is 10% by using a head space gas chromatograph.
20 pp in heptane conversion measured at 0 ° C. × 30 min.
m or less. 2. The viscosity average molecular weight of the polycarbonate resin is from 14,000 to 14,000 as calculated from the solution viscosity measured at a temperature of 25 ° C. using methylene chloride as a solvent.
The polycarbonate resin composition according to claim 1, wherein the composition is 30,000. 3. The polycarbonate resin composition according to claim 1, wherein the conductive substance is a conductive inorganic substance. 4. The polycarbonate resin composition according to claim 1, wherein the conductive substance is hollow carbon fibrils or carbon fibers. 5. The polycarbonate resin composition according to claim 1, wherein the conductive substance is a hollow carbon fibril. 6. The polycarbonate resin composition according to claim 4, wherein the outer diameter of the hollow carbon fibrils is 3 to 70 nm in number average. 7. The hollow carbon fibril has an aspect ratio of:
The polycarbonate resin composition according to any one of claims 4 to 6, wherein the number average is 5 or more. 8. A component for conveying electric / electronic components, which is obtained by molding the polycarbonate resin composition according to claim 1. 9. The molded article having a surface resistance of 10 ³ to 10 ¹²
9. The component for conveying electric / electronic parts according to claim 8, wherein the component is Ω.