WO2009060967A1

WO2009060967A1 - Process for producing polycarbonate resin pellet and molded article

Info

Publication number: WO2009060967A1
Application number: PCT/JP2008/070369
Authority: WO
Inventors: Seiichi Tanabe; Yoshiaki Abe; Moritoshi Matsumoto; Osamu Tokuda
Original assignee: Teijin Chemicals Ltd.
Priority date: 2007-11-06
Filing date: 2008-11-04
Publication date: 2009-05-14
Also published as: CN101842205A; JPWO2009060967A1; JP5119263B2; KR20100075929A; TW200927416A

Abstract

A process for producing polycarbonate resin reduced in the content of chlorine atoms and in the amount of chlorine ions dissolving out. The process comprises melting and extruding a powdery/granular polycarbonate resin with a twin-screw extruder to produce pellets, and is characterized in that as the twin-screw extruder, use is made of a twin-screw extruder in which (i) the extruder has at least one kneading-extruding unit comprising a water injection part, a kneading part, a seal ring, and a vent part, (ii) the most upstream element of the kneading part is a transverse disk (c) or progressive disk (f) and the most downstream element is a reverse feed disk (r), and (iii) each element of the kneading part has a length in the range of 0.25D to D and the kneading part has a length in the range of D to 4D, and that water is injected through the water injection part and the vent part is regulated so as to have a degree of vacuum of 6.7 kPa or lower.

Description

Description Manufacturing method and molded product of polycarbonate resin pellets Technical Field

The present invention relates to a method for producing a polycarbonate resin pellets suitably used as a material for a storage and conveyance container such as a silicon wafer or a magnetic disk, and a molded product thereof. Background art

In general, it is important that containers for storing and transporting thin plates sensitive to surface contamination, such as silicon wafers and magnetic disks, can be transported with the silicon wafer surface always kept normal.

Recently, with the increase in the diameter of silicon wafers, the demand for contamination from the container to the wafer surface has become stricter, and at the same time, a material with higher strength has been demanded. There are similar requirements not only for wafers but also for magnetic disk storage and transfer containers. Attempts have been made to use polycarbonate resins or resin compositions based on these as molding materials suitable for this requirement.

For example, in Patent Documents 1 to 4, contamination of the surface of a silicon wafer is prevented by removing impurities in polycarbonate resin and reducing the amount of volatile gas generated by heating at a high temperature. A method is described. However, the storage and transport containers for silicon wafers and magnetic disks are not used only once, but are washed with water and used repeatedly. Therefore, the storage and transport containers described in Patent Documents:! There is a problem that ionizable impurities are eluted, and ion impurities adhering to the surface of the container contaminate the surface of the wafer.

On the other hand, a method has been proposed in which water is injected at the time of melt extrusion to remove impurities in the poly-ponate resin. Patent Documents 5 to 7 propose a method of extruding polycarbonate resin powder with a vented extruder while injecting a small amount of water. But However, although these methods can remove impurities and chlorine compounds in the polycarbonate resin to some extent, they are insufficient as materials for the storage and transfer containers for wafers and the like as described above.

(Patent Document 1) Japanese Patent Laid-Open No. 10-211686

(Patent Document 2) Japanese Patent Laid-Open No. 11-241012

(Patent Document 3) International Publication No. 2000/043436 Pamphlet (Patent Document 4) Japanese Unexamined Patent Publication No. 2000-063505

(Patent Document 5) Japanese Patent Publication No. 05-048162

(Patent Document 6) Japanese Patent Publication No. 07-002364

(Patent Document 7) Japanese Unexamined Patent Publication No. 09-193230 Disclosure of Invention

An object of the present invention is to provide a method for producing a polycarbonate resin having a small chlorine atom content and a small amount of eluting chlorine ions. Another object of the present invention is to provide a method for producing a polycarbonate resin suitable as a raw material for a storage and transfer container that is less likely to contaminate the surface of a thin plate such as a silicon wafer or a magnetic disk that is sensitive to surface contamination. It is another object of the present invention to provide a molded product such as a storage / conveying container which is less likely to contaminate the surface of the storage.

As a result of diligent investigations to achieve the above object, the present inventor has improved the kneading performance immediately after water injection with a special structure of the screw configuration of the twin-screw extruder, and kneaded the polyponate resin efficiently. It was found that if the water was dispersed and mixed and then devolatilized with a vent, the devolatilization efficiency was improved, and it was possible to obtain a polycarbonate resin pellet with a low chlorine compound content. Further, it has been found that the molded product obtained from the pellets has few chlorine ions generated even when washed with water, and can be suitably used as a storage and transfer container for silicon wafers, magnetic disks and the like. The present invention is based on these findings.

That is, according to the present invention, in a method for producing a pellet by melting and extruding a polycarbonate resin granule with a twin screw extruder, (i) kneading comprising a water injection part, a kneading part immediately below the water injection part, a seal ring located upstream, downstream or both sides of the kneading part, and a vent part downstream of the water injection part Have at least one extruded unit,

(ii) The uppermost screw element in the kneading section is the orthogonal kneeing disk (c) or the progressive feeding disk (f), and the downstreammost screw element is the reverse feeding disk (r).

(iii) The length (1 ^;) of each screw element in the kneading part is in the range of 0.25 D to D, and the length (L ₂ ) of the kneading part is in the range of D to 4 D (D : Cylinder inner diameter), using a twin screw extruder,

Water injection portion (W) Force A method for producing a polycarbonate resin pellet is provided, in which water is injected and the degree of vacuum in the vent portion (V) is adjusted to 6.7 kPa or less.

According to the present invention, there is also provided a molded product formed from the polystrength Ponate resin pellet obtained by the production method.

Hereinafter, the present invention will be described in detail. Brief Description of Drawings

FIG. 1 is an example of the structure of a twin screw extruder used in the present invention.

FIG. 2 is a view showing the structure of the twin-screw extruder used in the example (screw A). FIG. 3 is a view showing the structure of the twin-screw extruder used in the example (screw B). FIG. 4 is a diagram showing the structure of the twin-screw extruder used in the example (Screw C). FIG. 5 is a view showing the structure of the twin-screw extruder used in the example (screw D). FIG. 6 is a view showing the structure of the twin-screw extruder used in the example (screw E). FIG. 7 is a view showing the structure of the twin screw extruder used in the example (screw F). Explanation of symbols

1 Water injection part

2 Kneading part

3 Seal ring 4 Vent part

5 Auxiliary vent

6 Additive introduction part Best mode for carrying out the invention

The polystrength resin resin used in the present invention is an aromatic polycarbonate resin obtained by reacting a divalent phenol and a carbonate precursor in the presence of a solvent by an interfacial polymerization method. Examples of the divalent phenol used here include hydroquinone, resorcin, 4,4, -dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, 1,1 bis (4-hydroxyphenyl) ethane, 2, 2 —Bis (4-hydroxyphenyl) propane (commonly known as bisphenol A), 2, 2_bis (3-methyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane (commonly known as Bisphenol Z), 2, 2-bis (3-phenyl-4-hydroxyphenyl) propane, 2,2-bis (3-isopropyl-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) 2) Butane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propan, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenyls Hoxide, 4, 4 '— Dihydroxydiphenylsulfide, 3, 3' — Dimethyl-4,4, -dihydroxydiphenylsulfide, 4, 4 '— Dihydroxydiphenyloxide, 9, 9-bis ( 4-hydroxyphenyl) fluorene, 9, 9-bis {(4-hydroxy _ 3-methyl) phenyl} fluorene, 1, 1-bis (4-hydroxyphenyl) 1, 3, 3, 5-trimethylcyclo Hexane, cu, 'bibis (4-hydroxyphenyl) 1m-diisopropylbenzene, 1,3-bis (4-hydroxyphenyl) 1,5,7-dimethyladamantane. Among them, bisphenol A, bisphenol Z, 9, 9-bis K4-hydroxy-1-methyl) phenyl} fluorene, 1,1-bis (4-hydroxyphenyl) -3, 3, 5-trimethylcyclo Xan, α, α '—Bi Su (4-hydroxyphenyl) 1m-diisopropylbenzene is preferred. These may be used alone or in combination of two or more.

As the carbonate precursor, carbonyl halide, haloformate, or the like is used, and specific examples include phosgene or dihaloformate of divalent phenol.

In producing the polyphonic resin by reacting the above divalent phenol with the carbonate precursor by the interfacial polycondensation method, a terminal stopper, a dihydric phenol antioxidant, etc. are used as necessary. May be. The polycarbonate resin is a branched polycarbonate resin copolymerized with a trifunctional or higher polyfunctional aromatic compound, but is a polyester carbonate resin copolymerized with an aromatic or aliphatic difunctional sulfonic acid. It may also be a mixture of two or more of the obtained polystrengthen one resin.

The reaction by the interfacial polycondensation method is usually a reaction between divalent phenol and phosgene, and is carried out in the presence of an acid binder, a catalyst and an organic solvent.

As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used.

Examples of the organic solvent include halogenated hydrocarbons such as methylene chloride, black form, 1,2-dichloroethane, 1,1-dichloroethane, promethane, butyl chloride, black propylene, and chlorobenzene. Are preferably used. These solvents are used alone or in combination of two or more.

Examples of amine-based catalysts used for promoting the reaction include tertiary amines such as triethylamine, tetra-n-butylammonium bromide, and tetra-n-butylphosphonium bromide, quaternary ammonium compounds, quaternary ammonium compounds, and the like. Examples thereof include catalysts such as phosphonium compounds, and triethylamine is particularly preferably used. The reaction temperature by the interfacial polycondensation method is usually from 0 to 40, the reaction time is from about 10 minutes to 5 hours, and the pH during the reaction is preferably kept at 9 or more.

In such a polymerization reaction, a terminal stopper is usually used. Such termination Monofunctional phenols can be used as the stopping agent. Monofunctional phenols are commonly used as end terminators for molecular weight control, and the resulting polycarbonate resin is not because the ends are blocked by groups based on monofunctional phenols. Excellent heat stability compared to Examples of such monofunctional phenols include phenol, p-tert-butyl phenol, ρ-cumyl phenol, and isooctyl phenol.

These end terminators are desirably introduced at least 5 mol%, preferably at least 10 mol%, based on the total end of the obtained polycarbonate resin. You may mix and use above.

The molecular weight of the polycarbonate resin, 1 X 10 ^⁴ ~4X 10 ⁴ is preferably a viscosity-average molecular weight (M), 1. more preferably ^{^{3 X 10 4 ~3 X 10 4}} , 1. 6X 10 4 ~2. 4X 10 4 Is particularly preferred. A poly-strength resin having such a viscosity-average molecular weight is preferable because it provides sufficient strength and has good melt fluidity during molding and does not cause molding distortion. Such viscosity-average molecular weight is one obtained by inserting a ratio determined from the solution of port Rica one Boneto resin 0. 7 g of methylene chloride 100ml at 20 ° C viscosity (r? _S _p) in the following equation.

_sp / c = [τ?] +0. 45X [τί] ² c (where [7?] is the intrinsic viscosity)

. [] = 1 23X 10 - 4 Μ 0 · 83

c = 0.7

The organic solvent solution of the poly-strength Pone resin obtained by the above reaction is usually washed with water. This water washing step is preferably carried out with water having an electric conductivity of 10 iS / cm or less, such as ion-exchanged water, and more preferably 1 S cm or less. The organic solvent solution and water are mixed and stirred, and then statically washed. The organic solvent solution phase and the aqueous phase are separated using a centrifuge or the like, and the organic solvent solution phase is removed repeatedly to remove water-soluble impurities. By washing with water, water-soluble impurities are removed, and the resulting polycarbonate resin has a good hue.

In addition, the organic solvent solution of the polycarbonate resin described above is preferably subjected to acid cleaning or alkali cleaning in order to remove impurities such as a catalyst. As the acid used for the acid cleaning, an aqueous solution of phosphoric acid, hydrochloric acid, sulfuric acid or the like is preferably used, and an aqueous solution having a concentration of 0.004 to 40 g / liter (or pH 5 or less) is preferably used. Examples of the alkali used for alkali cleaning include alkali metal compounds such as sodium hydroxide and potassium hydroxide, and alkaline earth metal compounds such as calcium hydroxide, barium hydroxide, and magnesium hydroxide. Sodium oxide is preferably used, and an aqueous solution having a concentration of 0.1 to 20 g / liter (or pH 1.5 or more) is preferably used.

The ratio of the aqueous solution to the organic solvent solution used for the alkaline cleaning and the acid cleaning is expressed in terms of the aqueous solution Z organic solvent solution (volume ratio). Preferably performed.

The organic solvent solution that has been washed with water is then subjected to an operation of removing the solvent to obtain a polycarbonate resin particle.

As a method to obtain polycarbonate resin granules (granulation process), operation and post-treatment force S Because of its simplicity, granulation with polycarbonate powder and hot water (about 40 to 90 ° C) A method of producing a slurry by continuously supplying an organic solvent solution of a polycarbonate resin into an apparatus while stirring and evaporating the solvent is preferably employed. As the granulator, a mixer such as a stirring tank is preferably employed.

Such a slurry can then be hydrothermally treated. In the hydrothermal treatment process, the slurry is supplied to a hot water treatment vessel containing hot water at 90 to 100 ° C or after being supplied, the water temperature is set to 90 to 100 ° C by blowing steam or the like. By using C, the organic solvent contained in the slurry is removed.

The slurry discharged in the granulation step or the slurry after the hot water treatment is preferably removed to some extent water and organic solvent by filtration, centrifugation, etc., and a wet paste of polycarbonate resin is recovered.

The wet paste of polycarbonate resin is then dried. The dryer may be a conduction heating method or a hot air heating method, and the polycarbonate resin may be allowed to stand, transport, or be agitated. Among them, the poly-one-pionate resin is stirred by the conductive heating method. A stirred channel or cylindrical dryer is preferred, and a channel dryer is particularly preferred. The drying temperature is preferably in the range of 130 ° C to 150 ° C.

In the present invention, the shape of the polycarbonate resin supplied to the kneading and extrusion treatment may be any of powder, fine particles, flakes, and pellets, preferably powder, fine particles, or flakes. belongs to.

In the present invention, the polycarbonate resin supplied to the kneading and extrusion treatment preferably has a chlorine atom content in the range of 5 to 2,00 ppm, and a range of 5 to 1,500 ppm. Is more preferable. If the chlorine atom content is in the above range, the object of the present invention is effectively achieved.

The twin-screw extruder has at least one kneading extrusion unit including a water injection part (1), a kneading part (2), a seal ring (3), and a vent part (4). The twin screw extruder preferably has an auxiliary vent part (5) and an additive introduction part (6). Fig. 1 shows an example of the structure of the twin screw extruder used in the present invention.

(Water injection part (1))

The water injection part is a part for injecting water. If there are 6 or more water injection parts, the resin will deteriorate, which is not preferable.

(Kneading part (2))

The kneading part is located immediately below the water injection part in the extruder and is a part for kneading the resin. In the present invention, the screw configuration of the kneading part is important.

The uppermost screw element in the kneading section is the orthogonal knee disk (c) or the progressive feed disk (f), and the most downstream screen element is the reverse feed disk (r).

Examples of screw configurations include forward feed (f)-reverse feed (r), as well as c-r, c-f-r, f-c-1r, c-c-r-r, f-f-r-r The combination is preferred.

The kneading disc is preferably a double thread type. The kneading angle of the kneading disc is preferably 15 to 90 degrees, more preferably 45 to 90 degrees. Each kneeing disk is composed of a plurality of disks, and the number of disks is preferably 2 to 7, more preferably 3 to 6.

The length of each screw element in the kneading part (LJ is in the range of 0.25D to D, preferably 0.5D to 0.75D. D is the inner diameter of the cylinder. The length of the kneading part (L ₂ ) is D to 4D, preferably 1.5 D to 3.5 D. The total length of all screws (L ₃ ) is preferably 28 D to 49 D, more preferably 31.5 D to 45.5 D. is there.

By making the screen of the kneading part as described above, the content of the chlorine compound in the polycarbonate pellet obtained is reduced. Molded articles formed from the obtained pellets have a small amount of elution of chlorine ions by water, and are suitably used as storage containers for silicon wafers and magnetic disks.

(Seal ring (3))

The seal ring is located on the upstream side, downstream side or both sides of the kneading part,

(Vent (4))

The vent part is located downstream of the water injection part and is a part for exhausting the gas generated by the kneading.

(Auxiliary vent (5))

The twin screw extruder preferably has an auxiliary vent portion upstream of the kneading extrusion unit. Therefore, the number of vent portions in the twin screw extruder is preferably 2 or more, more preferably 2 to 6, and further preferably 2 to 5. When the number of vents is one, the amount of residual chlorine in the obtained polycarbonate resin pellet tends to increase, and when the number of vents increases too much, the total length (L ₃ ) of all the screws of the extruder increases. Therefore, adverse effects such as resin degradation and resin degradation are likely to occur.

In the twin-screw extruder, the number of kneading extrusion units is preferably 1 to 5, more preferably 1 to 3, and further preferably 1 to 2.

(Additive introduction part (6))

The twin-screw extruder can have an additive introduction part on the downstream side of the kneading extrusion unit. The twin-screw extruder preferably has an auxiliary kneading section on the downstream side of the additive introduction section. In order to enhance the dispersibility of the additive, an auxiliary kneading part can be provided in the screw downstream of the additive introduction part. The screw configuration of the auxiliary kneading part is not particularly limited as long as the additive can be sufficiently kneaded. For example, a progressive kneading disc, an orthogonal binary disc, or a reverse kneading disc can be used alone or in combination.

Kneading is performed by injecting water from the water injection part and adjusting the vacuum degree of the vent part to 6.7 kPa or less.

If the amount of water injected from the water injection part is too small, the effect of water injection addition will not be manifested, and the chlorine atom content in the resulting polystrength Ponate resin pellets will not be reduced. Insufficient degassing in the water will cause adverse effects such as hydrolysis on the polycarbonate resin. Accordingly, the amount of water injected in the water injection part is preferably 0.1 to 5 parts by weight, more preferably 0.2 to 4 parts by weight per 100 parts by weight of the polystrength resin.

The injected water preferably has an electrical conductivity measured at 25 ° C of 1 S Z cm or less, and more preferably 0.5 S Z cm or less. Use of water having an electric conductivity of 1 S / cm or less is preferable because hydrolysis of the polycarbonate resin is less likely to occur, and a decrease in the molecular weight of the resin is suppressed.

Furthermore, the degree of vacuum in each vent of the twin screw extruder is 6.7 k Pa or less, and preferably 2. O k Pa or less. If the degree of vacuum is within the range, it is preferable that the injected and added water is sufficiently removed at the ben base, the amount of chlorine atoms is reduced, and the aromatic polycarbonate resin is not adversely affected by hydrolysis or the like.

The method for introducing the additive is not particularly limited, but the additive may be introduced alone, or a plurality of additives may be blended and introduced in advance. Alternatively, an additive master prepared by previously blending an additive with a raw material polyester resin granule may be added. If the melting point of the additive is low, it may melt and prock in the additive introduction section, so a method of introducing an additive master that has been previously blended with a polycarbonate resin granule and an additive into a twin screw extruder. Is preferred. The amount of additive to be introduced depends on the required properties. However, when additive mass is introduced, the additive mass is set to 0.1 to 0.1 to the resulting polycarbonate resin pellets (total extrusion amount). A power of 30% by weight S is preferable. The range is more preferably 0.2 to 20% by weight, and still more preferably 0.3 to 10% by weight. If an amount exceeding this range is introduced, the reduction effect of chlorine compounds and the like tends to be insufficient, and if an amount less than this range is introduced, the variation in the amount of additive introduced becomes large and the required characteristics cannot be imparted. There is.

Therefore, it is preferable to introduce 0.1 to 30% by weight of an additive master obtained by blending a polycarbonate resin granular material and an additive in advance into the twin screw extruder from the additive introduction part with respect to the obtained pellets. .

Various additives can be used in the polycarbonate resin pellet of the present invention and a molded product formed from the pellet in order to impart various characteristics within a range not impairing the object of the present invention. Additives include mold release agents, heat stabilizers, UV absorbers, brewing agents, antistatic agents, flame retardants, heat ray shielding agents, fluorescent dyes (including fluorescent whitening agents), pigments, light diffusing agents, reinforcing fillers Other resins and elastomers can be blended.

As the release agent, 90% by weight or more is preferably an ester of alcohol and fatty acid. Specific examples of the ester of alcohol and fatty acid include -valent alcohol and fatty acid ester and Z or partial ester or total ester of polyhydric alcohol and fatty acid. The ester of monohydric alcohol and fatty acid is preferably an ester of a monohydric alcohol having 1 to 20 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms. The partial ester or total ester of a polyhydric alcohol and a fatty acid is a partial ester or total ester of a polyhydric alcohol having 1 to 25 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms. .

Specific examples of the ester of a monohydric alcohol and a saturated fatty acid include stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, and isopropyl palmitate. Stearyl stearate is preferred. Specific examples of partial esters or total esters of polyhydric alcohols and saturated fatty acids include stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, stearic acid monosorbate, behenic acid monoglyceride, Rate, Pen Yu Erisri 1 ^ One Tetra Stearate, Pen Yu Erisri! ^ All of dipentaerythritol, such as monotetraperargonate, propylene glycol monostearate, biphenyl bibiate, sorbyl monostearate, 2-ethyl hexyl stearate, dipentaerythritol 1 ^ monohexa stearate Examples thereof include esters or partial esters.

Among these esters, stearic acid monoglyceride, stearic acid triglyceride, penicillary erythri] ^ monotetrastearate, and a mixture of stearic acid triglyceride and stearyl stearate are preferably used.

The amount of the ester in the release agent is preferably 90% by weight or more, more preferably 95% by weight or more, when the release agent is 100% by weight.

The content of the release agent in the polycarbonate resin granule is as follows. The force of the range of 0 · 05 to 2.0 parts by weight with respect to 100 parts by weight The range of 0.1 to 0.6 parts by weight is more preferable, and the range of 0.02 to 0.5 parts by weight is more preferable.

Examples of the heat stabilizer include phosphorus heat stabilizers, sulfur heat stabilizers and hindered phenol heat stabilizers.

Phosphorous acid stabilizers include phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid and their esters. Specifically, triphenyl phosphite, tris (nonylphenyl) phosphite, tris ( 2,4-di-tert-butylphenyl) phosphite, tris (2,6-di-tert-butylphenyl) phosphate, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, Dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monoptyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, bis (2,6-di-tert-petite 4-methylphenyl two ) Pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octylphosphite, bis (nonylphenyl) pen erythritol diphosphite, bis (2,4-di-tert- Butyl phenyl) Pen erythritol] , Diisopropylpropyl phosphate, dimethyl benzenephosphonate, jetyl benzenephosphonate, dipropyl benzenephosphonate, tetrakis (2,4-di-tert-butylphenyl) —4,4 ' Phenyl diphosphonate, tetrakis (2,4 di-tert-butylphenyl) 1,3,1 biphenyl di-range phosphonite, tetrakis (2,4-di-tert-butyl phenyl) 1,3,3 , Biphenyl bisphosphonates, bis (2,4-di-ter tert--butylphenyl) —4-phenyldiphenyl phosphonite and bis (2,4-di-tert-butylphenyl) tert-phenyldiphenylphospho Night etc. are mentioned.

Among them, tris (2, 4-ji tert-butylphenyl) phosphite, tris (2, 6 _di-tert-butylphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl)-4, 4, — Biphenylene diphosphonite, tetrakis (2, 4-di-tert-butylphenyl) —4, 3 '— Biphenylene diphosphonite, tetrakis (2, 4-di-1, 1; ert-butyl phenyl) 1, 3, 3 , -Biphenyl dirange phosphonite, bis (2,4-di-tert-butylphenyl) -4 monophenylphenyl phosphonite and bis (2,4-di-tert-butylphenyl) -1-3-diphenylphenyl phosphonite Particular preference is given to using tetrakis (2,4-di-tert-butylphenyl) -4,4′-piphenyl dirange phosphonite.

The content of the phosphorous heat stabilizer in the polycarbonate resin granules is preferably 0.001 to 0.2 parts by weight with respect to 100 parts by weight of the polyester resin granules. Sulfur-based heat stabilizers include Penyu Erythritol-Tetrakis (3-Lauryl Thiopropionate), pen erythritol-tetrakis (3-myristylthiopropionate), pentaerythri! ^ One rutetrakis (3-stearylthiopropionate), dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3 'monodipropionate Among them, pen erythritorutetrakis (3-laurylthiopropionate), erythritorutetrakis pen (3-myristylthiopropionate), dilauryl-3,3'-thiodipropionate, dimi Listyl 3,3 'monothiodipropionate is preferred. Particularly preferred is pen erythritol-tetrakis (3-laurylthiopropionate). The thioether compounds are commercially available from Sumitomo Chemical Co., Ltd. as Sumilizer TP-D (trade name), Sumilizer 1 TPM (trade name), etc., and can be easily used.

The content of the sulfur-based heat stabilizer in the polystrength resin resin granules is preferably 0.001 to 0.2 parts by weight with respect to 100 parts by weight of the polycarbonate resin granules. . As the hindered phenol thermal stabilizer, triethylene glycol monobis

[3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate], Penta Ellis! ^ One-Lu Tetrakis [3— (3,5-Di-tert-butyl-4-hydroxyphenyl) propionate], Octadecyl-3— (3,5-Di-tert-butyl-4-hydroxyphenyl ) Propionate, 1, 3, 5-trimethyl-2, 4, 6-tris (3, 5-di-tert-butyl-4-hydroxybenzyl) benzene, N, N-hexamethylenebis (3, 5-dione tert-butylene 4-hydroxy-hydrocinnamide), 3,5-di-tert-butyl 4-hydroxy monobenzylphosphonate-jetyl ester, tris (3,5-di-tert-butyl 4-hydroxybenzyl) ) Isocyanurate and 3, 9-bis {1, 1 dimethyl 1 2- [iS— (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2, 4, 8, 1 0 —Tetraxaspi Mouth (5, 5) undecane can be mentioned, and octadecyl-3- (3,5-ditert-butyl 4-hydroxyphenyl) propionate is particularly preferably used.

The content of the hindered phenolic heat stabilizer in the polycarbonate resin resin powder is 0.001 to 0.000 to 100 parts by weight of the polycarbonate resin resin powder. 3 parts by weight are preferred.

The UV absorber is at least one UV absorber selected from the group consisting of benzotriazole UV absorbers, benzophenone UV absorbers, triazine UV absorbers, cyclic imino ester UV absorbers and cyanoacrylates. Is preferred.

Benzotriazole UV absorbers include 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-1-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy — 3,5-Dicumylphenyl) Phenylbenzotriazol, 2- (2-Hydroxy-3_ tert-Butyl-5-methylphenyl), 1 5-Crobenzoylazol, 2, 2 '—Methylenebis [4- (1, 1, 3, 3-tetramethylbutyl) -6- (2N-benzotriazole-2-yl) phenol], 2- (2-hydroxy-1,3,5-di-tert-butylphenyl) Benzotriazol, 2- (2-hydroxy-3,5-di-tert-butylphenyl) — 5--clobenzobenzolazole, 2- (2-hydroxy-3,5-di-tert-amylphenyl) benzotriazole, 2— (2-hydroxy) 5-tert-octylphenyl) benzotriazole, 2_ (2-hydroxy-1-5-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-4-octoxyphenyl) benzotriazole, 2, 2, monomethylenebis (4-cumyl-6-benzotriazolphenol), 2, 2'-p-phenylenebis (1,3-benzoxazine-4-one), 2- [2-hydroxy-3- (3, 4, 5, 6-tetrahydrofluoroimidomethyl) -5-methylphenyl] benzotriazole, and these can be used alone or in a mixture of two or more. Preferably, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-3,5-dicumylphenyl) phenyl benzotri Azole, 2- (2-hydroxy-3-tert-butyl-5-methylphenol) 1-5-clobenzobenzol, 2, 2, 1 methylenebis [4- (1, 1: 3, 3-tetra Methylbutyl) -6- (2H-benzotriazole-2-yl) phenol], 2- [2-hydroxy-1-3- (3,4,5,6-tetrahydrophthalimidomethyl) -15-methylphenyl] Benzotriazole, more preferably 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2,2, -methylenebis [4- (1,1,3,3-tetramethylbutyl) An 6- (2 H- base Nzotoriazo Ichiru one 2-I le) phenol]. Benzophenone UV absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-1-4-methoxybenzophenone, 2-hydroxy-4-oxyoxybenzophenone, 2-hydroxy-4-benzene. Roxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxytrihydridolate benzophenone, 2, 2'-dihydroxy 4-methoxybenzophenone, 2 , 2, 4, 4, 4, 1-tetrahydroxybenzophenone, 2, 2, 1-dihydroxy-4, 4, 1-dimethoxybenzophenone, 2, 2, 2-dihydroxy-1, 4, 4, dimethyloxy _ 5—sodium sulfo Xybenzophenone, bis (5-benzoyl 4-hydroxy-1-2-methoxyphenyl) methane, 2-hydroxy-1- Examples include 4-n-dodecyloxybenzenphenone, 2-hydroxy-1,4-methoxy-1,2-carpoxybenzophenone.

Triazine-based UV absorbers include 2- (4, 6-Diphenyl 1, 3, 5, 5-triazine-2-yl) — 5— [(Hexyl) oxy] — Phenols, 2— (4, 6 —Bis (2, 4-dimethylphenyl) — 1, 3, 5-triazine-2-yl) 15-[(octyl) oxy] —phenol and the like.

Cyclic iminoester UV absorbers include 2, 2, 1bis (3, 1 Zoxazine _ 4—one), 2, 2 '1 p-phenylene bis (3, 1-benzoxazine 4-one), 2, 2' — m-phenylene bis (3, 1 benzoxazine 1 4-1 ON), 2, 2, 1 (4, 4, 1 diphenylene) Bis (3, 1 1 Benzoxazine— 4 1 ON), 2, 2 '-(2, 6 1 naphthenylene) Bis (3, 1-benzoxazine 4-one), 2, 2 'one (1,5-naphthalene) Bis (3, ■ 1-benzoxazine 4-one), 2, 2'-(2-methyl-p- Phenylene) Bis (3, 1-benzoxazine 4-one), 2, 2, 1 (2-Nitro-P-phenylene) Bis (3, 1-Benzoxazine 4-one) and 2, 2 ,-(2-chloro-p-phenylene) bis (3,1-benzoxazine-4-one) and the like. Among them, 2, 2 '_p—Phenylene bis (3,1 benzoxazine-4-one), 2, 2'-(4,4,2-diphenylene) bis (3,1 benzoxazine 4-one) And 2, 2, 1 (2, 6 1 naphthalene) bis (3, 1 1 benzoxazine — 4 1-one) are preferred, especially 2, 2′-P-phenylenediamine (3, 1-benzoxazine 1 4-on) is preferred. Such a compound is commercially available from Takemoto Yushi Co., Ltd. as CEi-P (trade name) and can be easily used.

Cyanacrylate-based UV absorbers include 1,3-bis-[(2,2-cyanol 3,3,1-diphenylacryloyl) oxy] —2,2-bis [(2-cyanol 3,3— Examples include diphenylacryloyl) oxy] methyl) propane, and 1,3-bis ([(2-cyano-3,3-diphenylacryloyl) oxy] benzen.

The blending amount of the UV absorber is preferably 0.01 to 3.0 parts by weight, more preferably 0.02 to 1.0 parts by weight with respect to 100 parts by weight of the polypone resin resin granules. Furthermore, it is more preferably 0.05 to 0.8 parts by weight. Within such a range of blending amounts, it is possible to impart sufficient weather resistance to a polystrength Ponate resin molded product depending on the application.

Blueing agents include Macrolex Biolet B and Macrolex Blue RR from Bayer and Polysynthlumble -RL S from Clarian Co. Etc. The bluing agent is effective for eliminating the yellowish color of the polycarbonate resin granules. In particular, in the case of poly strength monoponate resin granules with weather resistance, a certain amount of UV absorber is blended, so the polycarbonate resin molded product has a yellowish color due to the action and color of the UV absorber. In particular, blending with a bluing agent is very effective for imparting a natural transparency to the sheet lens.

The blending amount of the brewing agent is preferably based on the polycarbonate resin particle

0.05-: L. 5 p pm, more preferably 0.1-1.2 ppm. The resin temperature at the time of kneading and extruding the polycarbonate resin is appropriately set depending on the molecular weight of the polycarbonate resin and the like, and is preferably about 270 to 350.

The polycarbonate resin pellet obtained by the above-described method is molded by an ordinary method such as extrusion molding or injection molding. The present invention includes a molded article formed from a polycarbonate resin pellet obtained by the method described above.

Molded articles formed from such polycarbonate resin pellets have a marked decrease in the amount of chlorine eluted with water.

The molded product has a heat treatment in water at 80 ° C for 24 hours, and the amount of chlorine ions dissolved in water from the molded product is preferably 10 ngZcm ² or less, more preferably 9 ng / cm ² or less. . The lower limit is not particularly limited, but it is difficult to make it lower than 0.5 ng / cm ² . Such a molded article is suitably used as a storage / transport container for silicon wafers or magnetic disks. Example

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the examples, parts are parts by weight, and% indicates% by weight unless otherwise specified. Evaluation was performed by the following method.

(1) Chlorine ion content: Cut sample plate having a thickness of 1mm obtained by injection molding a poly force one Poneto resin Peretsuto vertical 2 Omm, the magnitude of the lateral 25 mm, placed in extraction pack was sealed by addition of ultrapure water 15 cm ³ After heating at 80 ° C for 24 hours, the mixture is allowed to cool to room temperature, then C 1— in water is quantified by ion chromatography, and the amount of C 1— extracted per 1 cm ³ of surface area of the molded product is obtained. It was. The equipment and conditions used are shown in Table 1 below.

table 1

(2) Chlorine atom content:

The polycarbonate resin pellet was completely burned, and the hydrogen chloride (HC 1) produced was subjected to potential titration with silver ions (Ag +), and the chlorine atom content was determined from the amount of electricity required for this potential titration.

(3) Hue (pellet b value):

The b value was measured using a hue meter (Nippon Denshoku Co., Ltd. SE-2000). The higher the b value, the more yellowish it is, indicating that the thermal stability of the polycarbonate resin during melt extrusion was poor. Examples 1 to: L 1 and Comparative Examples 1 to 5

The number of vents shown in Fig. 2 to Fig. 7 is three (V1, V2, V3 from the vent close to the raw material supply hopper), and the water injection part (from the water injection point close to the raw material supply hopper) immediately before vents V2, V3 Wl and W2) are used, and the raw material resins and additives listed in Table 2 can be obtained by using a twin screw extruder with a screw diameter of 30mm Φ (Nippon Steel Works ΤΕΧ30 α, LgZD = 45.5 for the entire screen configuration). Supplied, extruded into strands under the extrusion conditions listed in Table 2, and cut to produce pellets. The additive is blended with the following resin raw material C in advance to prepare a master powder having a concentration 50 times the target addition amount, and the master powder is obtained from the additive introduction part polycarbonate resin pellet (resin raw material and master It was introduced at a rate of 2% by weight with respect to the total amount of powder. Table 3 shows the target additive amounts. The evaluation results of the obtained polycarbonate resin pellets are shown in Table 4.

In Table 2, the raw materials and additives, and the "Screw" symbol for the water injection part are as follows.

Resin raw material A: Polycarbonate resin powder with a viscosity average molecular weight of 18 and 500 (reacted chlorine source ^ M 50 ppm) obtained by reacting bisphenol A and phosgene in a conventional manner in methylene chloride.

Resin raw material B: Polycarbonate resin powder (chlorine atomic weight 2 3 6 ppm) obtained by reacting bisphenol A and phosgene in a conventional manner in methylene chloride and having a viscosity average molecular weight of 18 and 500 .

Resin raw material C: Polypionate resin powder with a viscosity average molecular weight of 2 and 400 obtained by reacting bisphenol A and phosgene in a conventional manner in salt methylene chloride (chlorine atomic weight 88 ppm) It is.

Additive:

UV absorber; 2- (2-hydroxy-5-ter-tylphenyl) benzotriazole

Mold release agent; pentaerythritol tetrastearate

Phosphorus stabilizer; Tris (2, 4-di-tert-butylphenyl) phosphatamine

Hindered phenol-based heat stabilizer; octyldecyl-3- (3,5-di-tert-petit-l-hydroxyphenyl) propionate

Brewing agent; Bayer Macrolex Violet B

Screw A (see Fig. 2):

Place a seal ring (length: 0.5 D) at a location of 1.0 D upstream from the nozzle hole in the water injection section of the extruder, and an orthogonal kneading disc (length: 0.5 D; length) from the ring to the downstream. 0. Consists of 5 ID discs), 2 reverse feed needing discs (length 0.5D; length 0. 5 ID discs), 2 seal rings (length) (5D) is the squeegee shape of the water injection part (the twist angle of the screw element in the kneading part is 90 degrees for the orthogonal disk and 45 degrees for the reverse feed disk, and L ₂ is 2 0D).

Screw B (see Fig. 3):

Place a seal ring (length 0.5D) upstream from the nozzle hole of the water injection section of the extruder at a position J1.0D, and feed it progressively downstream from the ring (length 0.5D; length 0. 0). 3 discs (composed of 5 1D discs), 1 reverse disc needing disc (length 0.5D; composed of 5 discs of length 0.1D), and 1 seal ring (length 0.5D) ) The screw shape of the water injection part (the twist angle of the screw element in the kneading part is 45 degrees for the forward kneading disc and 45 degrees for the reverse feeding disc, and L ₂ is 2.0D) Have

Screw C (see Fig. 4):

This is a screw configuration in which screw A has a seal ring (length 0.5D) placed 1.0D upstream from the nozzle hole in the water injection part of the extruder and replaced with a normal full flight disk.

SCREW D (see Figure 5):

In screw A, an additive introduction part is provided on the downstream side of the vent (V3) on the downstream side of the water injection part (W2) of the extruder, and a progressive kneading disc (length 0.5D; length 0) is further provided on the downstream side. (It is composed of 5 1D discs). The slewing configuration of the squeegee element in the auxiliary kneading section is 45 degrees for the progressive kneading disc and L ₂ is 1.0D.

Screw E (see Fig. 6):

In SCREW B, instead of the reverse feed needing disc, this is a screw configuration using a progressive feed disc.

Screw F (see Fig. 7):

In screw D, orthogonal kneading disc and reverse feeding Instead of a disk, all of them are screwed using a progressive kneading disk.

Table 2

CO

Table 3

Table 4

Example 1 2 and Comparative Example 6

The pellets obtained in Example 1 and Comparative Example 1 were used to mold a silicon wafer storage and transfer container. This silicon wafer storage and transfer container was immersed in warm water at 80 ° C. for 24 hours. After that, the container is dried, a predetermined number of silicon wafers are inserted into this container, kept at room temperature for one week in a sealed container, then the silicon wafer is taken out, and water and one wafer surface are placed at five locations on the surface. The contact angle was measured. Table 5 shows the average of the measured contact angles. The contact angle between water and the wafer surface is a measure of the degree of contamination of the wafer surface. A large contact angle increases the hydrophobicity of the wafer surface and the degree of contamination. Indicates a high degree. The contact angle is preferably 10 degrees or less. Table 5

The invention's effect

According to the present invention, in the kneading part of the 7K injection part, by using a twin-screw extruder with a vent having a material seal equipped with a screw having an excellent water dispersion effect, the chlorine ion content is low and the eluted chlorine ions A polycarbonate resin with a small amount of is obtained. According to the present invention, it is possible to obtain a polycarbonate resin that is suitable as a raw material for a storage and conveyance container that is less likely to contaminate the surface of the stored item. According to the present invention, a polycarbonate resin suitable as a raw material for a storage and transfer container such as a silicon wafer or a magnetic disk can be obtained. According to the present invention, it is possible to obtain a storage and conveyance container that is less likely to contaminate the surface of the stored item. Industrial applicability

The polystrength Ponate resin obtained by the production method of the present invention is suitably used as a material for forming a storage and conveyance container such as a silicon wafer or a magnetic disk that is sensitive to surface contamination.

Claims

1. Polycarbonate resin granules are melt-extruded with a twin-screw extruder to produce pellets.

(i) kneading extrusion comprising a water injection part, a kneading part immediately below the water injection part, a seal ring located upstream, downstream or both sides of the kneading part, and a vent part downstream of the water injection part Have at least one unit,

Contract

(ii) The uppermost screw element in the kneading section is the orthogonal knee disk (c) or the progressive feed disk 2 (f), and the most downstream screw thread is the reverse feed disk (r). Yes,

(iii) Length range of each screw element in the kneading part (L is in the range of 0.25D to D, and length of the kneading part (L ₂ ) is in the range of D to 4D (D: cylinder inner diameter) ), Using a twin screw extruder,

A method for producing polycarbonate resin pellets, wherein water is injected from the water injection part (W) and the degree of vacuum of the vent part (V) is adjusted to 6.7 kPa or less.

2. The production method according to claim 1, wherein the twin-screw extruder has an additive introduction part on the downstream side of the kneading extrusion unit, and the additive is introduced from the additive introduction part.

3. The production method according to claim 2, wherein the twin-screw extruder has an auxiliary kneading section downstream of the additive introduction section.

4. The additive master obtained by previously blending the polycarbonate resin granules and the additive into the twin screw extruder from the additive introduction part is introduced in an amount of 0.1 to 30% by weight based on the pellets obtained. Manufacturing method.

5. The production method according to claim 1, wherein the total length (L ₃ ) of all the screws of the twin-screw extruder is in a range of 28D to 49D (D: inner diameter of cylinder).

6. The production method according to claim 1, wherein the twin-screw extruder has an auxiliary vent portion upstream of the kneading extrusion unit.

7. The production method according to claim 1, wherein the water injection amount is 0.:! To 5 parts by weight per 100 parts by weight of the polycarbonate resin.

8. A molded article formed from a polycarbonate resin pellet obtained by the production method according to claim 1.

9. A molded product in which the amount of chlorine ions eluted from the molded product into water after heating the molded product in water at 80 ° C for 24 hours is 10 ng / cm ² or less.

10. The molded article according to claim 8 or 9, which is a container for storing and transporting silicon wafers or magnetic disks.