JP2005075914A - Molded product for clean room and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molded product for a clean room, having a surface resistivity within a prescribed range having narrow dispersion even in various parts of the molded product, not allowing the molded product itself to be a pollutant source, and having good dimensional stability and appearance. <P>SOLUTION: The molded product for the clean room, having 10<SP>5</SP>-10<SP>12</SP>Ω/square surface resistivity is produced by subjecting a resin composition comprising 60-80 wt.% cyclic olefin polymer and 20-40 wt.% carbon fiber having 10<SP>-1</SP>-10<SP>3</SP>Ω cm volume specific resistivity value, 5-30 μm fiber diameter and 0.1-1 mm fiber length to injection molding under a prescribed condition. A container in which a board-shaped body selected from a semiconductor substrate, a display substrate and a recording medium substrate is stored, and a jig, a tool or the like for treating a raw material, an intermediate product or a finished product, are suitable embodiments. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a molded product for a clean room comprising a resin composition comprising a cyclic olefin polymer and carbon fiber, and a method for producing the same.

  Silicon wafers in the semiconductor manufacturing process, glass substrates in the liquid crystal panel manufacturing process, and metal disks in the hard disk manufacturing process are handled in a clean room to prevent contamination. In these manufacturing processes, various resin molded products such as containers, trays, and tweezers for efficiently handling these substrates are used. For example, jigs such as containers that accommodate multiple substrates simultaneously and transport them from one process to the next in a clean room, containers for various processing, and tweezers that carry single wafers are used. Has been. These molded products used in a clean room are often subjected to antistatic treatment in order to handle electronic devices.

  When two conductive materials having different charge levels come into contact with each other, charge transfer occurs instantaneously, the charge levels become equal, and current flows. It is considered that ESD (Electrostatic Discharge) destruction of a device is caused by a current generated by the movement of the charge. Therefore, in order to protect the device from ESD destruction, it is important to control the speed of movement of this charge and to control the generated current. That is, ESD breakdown is suppressed by using a material that has a relatively low charge transfer rate and is not charged as a member in contact with the device.

  In addition, with regard to cleaning technology, attention has been focused on ESA (Electrostatic Attraction) due to contamination of semiconductor wafers and the like. In particular, in recent years, the particle size to be managed has been reduced to 0.3 μm or less with the miniaturization of devices, so that the deposition on the wafer by ESA has become more dominant than the gravity sedimentation, and the ESA countermeasures are further improved. It is important.

When the surface resistivity of the molded product is larger than 10 ¹² Ω / □, not only charging due to friction but also adsorption of particles due to charging tends to occur. In order to prevent ESD damage, it is important to control the surface resistivity within a range of about 10 ⁵ to 10 ¹² Ω / □. Therefore, a technique that can strictly control the surface resistivity of a molded product used in a clean room is desired.

Japanese Patent Laid-Open No. 5-117446 (Patent Document 1) is composed of 10 to 40 parts by weight of short carbon fibers having a volume resistivity of 10 ⁻¹ to 10 ³ Ω · cm and 90 to 60 parts by weight of a polymer. In addition, a resin composition having a volume resistivity value of 10 ⁵ to 10 ¹³ Ω · cm is described. It is said that a short fiber-containing resin composition whose volume specific resistance value is controlled in a certain range can be obtained by using carbon fibers having a higher resistance value than ordinary carbon fibers. However, cyclic olefin polymers are not described in the examples of polymers used herein.

Japanese Patent Application Laid-Open No. 7-126434 (Patent Document 2) comprises a resin composition obtained by blending 1 to 50 parts by weight of a blend of two types of carbon fibers with 100 parts by weight of a thermoplastic norbornene resin. The molded product is described. The surface resistance value of the molded product is preferably 10 ⁵ to 10 ¹² Ω, and shows almost the same value regardless of the portion of the surface of the molded product, and there is no unevenness. The carbon fiber used here is a carbon fiber having a normal volume resistivity value, that is, a volume resistivity value of 10 ⁻¹ Ω · cm or less. However, when carbon fibers having a low volume resistivity are used as described above, it is possible to obtain a relatively high surface resistivity with good reproducibility by suppressing variation in a clean room molded product that often has a complicated shape. ,It's not easy. Moreover, since cutting of carbon fibers is inevitable in the melt-kneading operation, it is not easy to control the surface resistivity by blending two types of carbon fibers. Furthermore, carbon fibers that are too short can cause dusting.

Japanese Patent Laid-Open No. 5-117446 JP-A-7-126434

  The present invention has been made in order to solve the above-mentioned problems, and is capable of suppressing both ESD and ESA, has a slow charge transfer rate, and has a surface resistivity within a range not charged. And it aims at providing the manufacturing method. In particular, it is an object of the present invention to provide a molded product having a surface resistivity with little variation even in various parts of a complex molded product. Furthermore, it is an object of the present invention to obtain a molded product in which the molded product itself does not become a contamination source and has good dimensional accuracy.

The above-mentioned problems are 60 to 80% by weight of a cyclic olefin polymer, a carbon fiber having a volume resistivity of 10 ⁻¹ to 10 ³ Ω · cm, a fiber diameter of 5 to 30 μm, and a fiber length of 0.1 to 1 mm. This can be solved by providing a molded product for a clean room comprising a resin composition comprising 20 to 40% by weight. At this time, the deflection temperature under load of the cyclic olefin polymer (Td: measured at 1.82 MPa stress based on ASTM D648) is preferably 60 to 150 ° C. It is also preferable that the carbon fiber is not attached with a sizing agent. The MFR (measured at 240 ° C. under a load of 2.16 kg based on ASTM D1238) of the resin composition is preferably 0.2 to 10 g / 10 min.

Moreover, the said subject is a cyclic olefin polymer 60-80 weight%, a volume resistivity value is 10 < ^-1 > -10 < ³ > (omega | ohm) * cm, a fiber diameter is 5-30 micrometers, and fiber length is 0.1-1 mm. The problem can also be solved by providing a resin composition for a molded product for a clean room comprising 20 to 40% by weight of carbon fiber.

In the molded product for the clean room of the present invention, it is preferable that the surface resistivity is 10 ⁵ to 10 ¹² Ω / □. It is also preferable that the ratio between the maximum value and the minimum value when the surface resistivity is measured at a plurality of positions of the molded product is 100 or less. Furthermore, it is also preferable that the total amount of degassing when heated at 150 ° C. for 30 minutes is 10 μg / g or less in terms of hexadecane. A preferred embodiment of the molded product for a clean room of the present invention includes a container in which a plate-like body selected from a semiconductor substrate, a display substrate, and a recording medium substrate is stored. In addition, as another preferred embodiment, a tool for handling a raw material, an intermediate product, or a finished product may be used.

Moreover, the said subject is a cyclic olefin polymer 60-80 weight%, a volume resistivity value is 10 < ^-1 > -10 < ³ > ohm * cm, a fiber diameter is 5-30 micrometers, and fiber length is 0.1. The problem can also be solved by providing a method for producing a molded product for a clean room, in which a resin composition obtained by melt-kneading 20 to 40% by weight of carbon fibers of ˜1 mm is injection molded.

At this time, the cylinder set temperature (Ts) at the time of injection molding and the deflection temperature under load of the cyclic olefin polymer (Td: measured at 1.82 MPa stress based on ASTM D648) satisfy the following formula (1). Is preferred.
Td + 140 ≦ Ts ≦ Td + 200 (1)
It is also preferable that the injection speed is 20 to 200 ml / sec. Furthermore, it is also preferable that the mold temperature (Tm) and the deflection temperature under load of the cyclic olefin polymer (Td: measured at 1.82 MPa stress based on ASTM D648) satisfy the following formula (2).
Td−40 ≦ Tm ≦ Td + 10 (2)

  Since the clean room molded article of the present invention has a low charge transfer speed and a surface resistivity in a range not charged, it can suppress both ESD and ESA. In particular, even in various parts of a complex molded product, the surface resistivity can be reduced. Further, the molded product itself does not become a contamination source, and the dimensional accuracy is good. Moreover, the manufacturing method of the molded product for clean rooms of this invention is a manufacturing method suitable for obtaining such a molded product.

  The present invention is a molded product for a clean room comprising a resin composition comprising a cyclic olefin polymer and carbon fibers.

  The cyclic olefin polymer used in the present invention is a non-crystalline, transparent one having a saturated hydrocarbon ring structure in the main chain or side chain of the polymer, specifically, JP-A 63-264646. , JP-A 64-1705, JP-A-1-168724, JP-A-1-168725, etc., a ring-opening polymer of a monomer having a norbornene ring, and a hydrogenated product thereof, Addition polymers of a monomer having a norbornene ring and an α-olefin disclosed in JP-A-60-168708, etc., cyclic compounds disclosed in JP-A-6-136057, JP-A-7-258362, etc. Examples thereof include addition polymers of olefins and cyclic dienes and hydrogenated products thereof. These resins are sold, for example, under the trade names “Apel” and “Topas” from Mitsui Chemicals, Inc. and under the trade names “Zeonex” and “Zeonoa” from Nippon Zeon Co., Ltd. It can be easily obtained. These commercial products often contain additives to improve durability and moldability, so in order to minimize contamination in the clean room, the resin before the additives are added It may be preferable to use and mold. In some cases, it is preferable to use a resin in which the catalyst residue and residual volatile matter are particularly reduced.

  Since the cyclic olefin polymer is a polymer having a bulky skeleton, the molded product is difficult to be oriented, and in particular, even in the molded product of the present invention in which anisotropy is easily developed by blending carbon fibers. A molded product having a surface resistivity is easily obtained. In addition, since the cyclic olefin polymer has a small shrinkage ratio from the mold dimensions at the time of molding, it is easy to obtain a molded product with good dimensional accuracy. Furthermore, when there is no functional group, the water absorption rate is low, so that it is not easily affected by physical properties or dimensional changes due to water absorption.

As the monomer having a norbornene ring, a bicyclic olefin bicyclo [2.2.1] hept-2-ene (ordinary name: norbornene), which is an adduct of ethylene and cyclopentadiene, and a tetracyclic structure in which cyclopentadiene is added. Olefin Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -dodec-3-ene (also simply referred to as tetracyclododecene), a tricyclo [4.3.0.1 ^2,5 ] deca-3, which is a dimer of cyclopentadiene and a tricyclic diene. , 7-diene (common name dicyclopentadiene), tricyclo [4.3.0.1 ^2,5 ] dec-3-ene, which is a tricyclic olefin in which a part of the unsaturated bond is saturated by hydrogenation Pentacyclo [6.5.1.1 ^3,6 .., a trimer of cyclopentadiene and a pentacyclic diene. 0 ^2,7 . 0 ^9,13] pentadeca-3,10-diene and pentacyclo [7.4.0.1 ^3,6. 1 ^10,13 . 0 ^2,7 ] pentadeca-4,11-diene, pentacyclo [6.5.1.1 ^3,6 . Which is a pentacyclic olefin in which a part of its unsaturated bond is saturated by hydrogenation. 0 ^2,7 . 0 ^9,13] pentadeca-3,10-diene and pentacyclo [7.4.0.1 ^3,6. 1 ^10,13 . 0 ^2,7 ] pentadeca-4,11-diene; and substituted products thereof.

Examples of the substituent include a derivative substituted with a group having no polar group such as an alkyl group, an alkylidene group, or an aromatic group, a hydrogenated derivative, or a derivative obtained by dehydrogenation thereof (for example, 2-methyl-bicyclo [2.2.1] hept-2-ene, 2,2-dimethyl-bicyclo [2.2.1] hept-2-ene, 2-ethyl-bicyclo [2.2.1] hept-2-ene 2-butyl-bicyclo [2.2.1] hept-2-ene, 2-hexyl-bicyclo [2.2.1] hept-2-ene, 2-phenyl-bicyclo [2.2.1] hepta Such as 2-ene, 2-octyl-bicyclo [2.2.1] hept-2-ene, 2-octadecyl-bicyclo [2.2.1] hept-2-ene, 2-ethylidene-2-norbornene, etc. Bicyclic norbornene induction , 8-methyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] - dodeca-3-ene, 8-ethyl tetracyclo [4.4.0.1 ^2,5 .1 ^{7, 10]} - dodeca-3-ene, 8-methylidene-tetracyclo [4.4.0.1 ^{2, 5} .1 ^7,10] - dodeca-3-ene, 8-ethylidene tetracyclo [4.4.0 .1 ^2,5 .1 ^7,10] - dodeca-3-ene, 8-vinyl-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] - dodeca-3-ene, 8- propenyl - tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] - such as derivatives of 4 rings having a tetracyclododecene (4 annulus) structure such dodeca-3-ene); halogen, hydroxyl Substituted with a polar group such as ester group, alkoxy group, cyano group, amide group, imide group, silyl group (for example, 5-methoxy-bicyclo [ 2.1] hept-2-ene, 5-cyano-bicyclo [2.2.1] hept-2-ene, 5-methyl-5-methoxycarbonyl-bicyclo [2.2.1] hept-2- ene such as 3- methyl-3-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] - dodeca-3-ene) can be mentioned. Among these norbornenes, those having no polar group are preferable because the contents of the resulting container are less contaminated.

  Examples of the α-olefin include olefinic monomers in which a part of these is substituted with a polar group such as halogen in addition to olefins in a narrow sense such as ethylene, propylene, 1-butene and 4-methylpentene-1.

  Cyclic olefins include cyclobutene, 1-methylcyclopentene, 3-methylcyclobutene, 3,4-diisopropenylcyclobutene, cyclopentene, 3-methylcyclopentene, cyclohexene, cyclooctene, 1-methylcyclooctene, 5-methylcyclo Among the monomers having a monocyclic cycloolefin such as octene, cyclooctatetraene, cyclododecene or the norbornene ring, those having one unsaturated bond may be mentioned.

  Examples of the cyclic diene include monocyclic dienes such as cyclopentadiene, 1,3-cyclohexadiene, and 1,4-cyclohexadiene, and those having two unsaturated bonds among the monomers having the norbornene ring. .

  Furthermore, in both the ring-opening polymerization and the addition polymerization, various copolymerizable monomers may be copolymerized in the catalyst system to be polymerized. Examples of the copolymerizable monomer include linear or branched dienes such as butadiene and isoprene, in addition to the monomer having a norbornene ring, an α-olefin, a cyclic olefin, and a cyclic diene. The polymerization may be random, block-type, or alternating-type, and either 1,2-addition or 1,4-addition may be the main in addition polymerization.

  In the case where an unsaturated bond remains in the polymer after polymerization, that is, in the case of a ring-opening polymer of a monomer having a norbornene ring or an addition polymer of a cyclic diene, the remaining unsaturated bond causes the weather resistance stability of the polymer. Since the thermal stability is lowered, for the purpose of improving this, it is preferable to saturate 80% or more, preferably 90% or more of the unsaturated bonds by hydrogenation. About a hydrogenation method and a hydrogenation catalyst, it can carry out by a well-known method.

  Among the cyclic olefin polymers, a random copolymer of ethylene and a monomer having a norbornene ring (norbornenes) is preferably used. This is because this random copolymer is excellent in dimensional accuracy at the time of molding, has a low water absorption rate, and generates less degassing due to decomposition during heating. The content of the monomer having a norbornene ring is preferably 10 to 50 mol%, more preferably 20 to 40 mol%. Since the heat resistance of the resin improves as the content of the monomer having a norbornene ring increases, the resin is appropriately adjusted according to the application.

  Among the cyclic olefin polymers, hydrogenated products of ring-opening polymers of monomers having norbornene rings (norbornenes) are also preferred. This polymer hydrogenated product is also excellent in dimensional accuracy at the time of molding, has a low water absorption, and generates less degassing due to decomposition during heating. In the case of a hydrogenated product of a ring-opening polymer of norbornenes, the bicyclic or tricyclic norbornenes in norbornenes are 50% by weight or more, preferably 60% by weight or more, particularly preferably 70% by weight or more. Yes, up to 100% by weight. When the amount of the bicyclic or tricyclic norbornene is in such a range, the balance between the heat resistance and moldability of the molded container is improved. In the case of ring-opening polymerization, the total amount of norbornenes among all the monomers is 70% by weight or more, preferably 80% by weight or more, particularly preferably 90% by weight or more, and 100% by weight or less.

  The load deflection temperature (Td) of the cyclic olefin polymer used as a raw material in the present invention is preferably 60 to 150 ° C. This deflection temperature under load is measured with a stress of 1.82 MPa based on ASTM D648. When the deflection temperature under load is less than 60 ° C., the obtained molded article has insufficient heat resistance, more preferably 70 ° C. or more, and further preferably 80 ° C. or more. On the other hand, when the deflection temperature under load exceeds 150 ° C., the temperature at the time of melt-kneading with carbon fiber or at the time of injection molding becomes too high, and there is a possibility that the thermal decomposition products increase. In this case, if the molding temperature is lowered to suppress thermal decomposition, the moldability deteriorates, making it difficult to obtain a molded product having a uniform surface resistivity, and the surface condition of the molded product. There is a risk of worsening. The deflection temperature under load is more preferably 140 ° C. or less, and further preferably 130 ° C. or less.

  The MFR of the cyclic olefin polymer used as a raw material in the present invention is preferably 1 to 30 g / 10 minutes. This MFR is measured at 240 ° C. under a load of 2.16 kg based on ASTM D1238. When the MFR is less than 1 g / 10 min, the melt viscosity of the resin composition becomes too high, the moldability is deteriorated, and a large shearing force is generated at the time of injection molding, which may cause decomposition of the resin. MFR is more preferably 1.5 g / 10 min or more, and even more preferably 2 g / 10 min or more. On the other hand, if the MFR exceeds 30 g / 10 min, the strength of the molded product may be insufficient, and dust generation due to friction and impact is likely to occur. MFR is more preferably 20 g / 10 min or less, and even more preferably 15 g / 10 min or less.

The volume specific resistance value of the carbon fiber contained in the molded article of the present invention is 10 ⁻¹ to 10 ³ Ω · cm. Most of the carbon fibers currently on the market have a volume resistivity value of less than 10 ⁻¹ Ω · cm. Compared with this, it is possible to use carbon fibers having a large volume resistivity value. It is a big feature. By using such a carbon fiber having a large volume resistivity, it is possible to prevent the surface resistivity from becoming too small even when carbon fiber is blended at a high filling rate. . In order to stably reproduce a relatively large surface resistivity, the volume resistivity of the carbon fiber is more preferably 10 ⁰ to 10 ³ Ω · cm, and even more preferably 10 ¹ to 10 ³ Ω. -Cm.

  Moreover, the fiber diameter of the carbon fiber contained in the molded product of this invention is 5-30 micrometers. The fiber diameter here is the fiber diameter observed with an optical microscope. In normal carbon fiber, although the fiber length varies, the fiber diameter is almost constant for each fiber. When the fiber diameter is less than 5 μm, it is difficult to produce the fiber and it is easy to be cut, and is preferably 10 μm or more. On the other hand, if the fiber diameter exceeds 30 μm, the number of contact points between the carbon fibers in the resin composition may decrease, and it may be difficult to develop uniform conductive performance, preferably 20 μm or less. is there.

  Moreover, the fiber length of the carbon fiber contained in the molded article of the present invention is 0.1 to 1 mm. The fiber length here is obtained as a length-weighted weighted average length, and the measuring method is as shown in the examples. Since carbon fibers are often partially cut by melt-kneading, the length of carbon fibers taken out from a molded product is measured. When the fiber length of the carbon fiber exceeds 1 mm, the fluidity of the resin composition may be deteriorated and the dispersion of the carbon fiber into the resin may be insufficient. In particular, in the present invention, since the carbon fiber is blended at a blending ratio of a certain amount or more, the melt viscosity of the resin composition is increased, and shearing heat generation is likely to occur. Therefore, decomposition of the resin due to such shearing heat generation is prevented. Therefore, it is important that the fiber length of the carbon fiber is 1 mm or less. The fiber length is preferably 0.6 mm or less, and more preferably 0.4 mm or less. On the other hand, when the fiber length of the carbon fiber is less than 0.1 mm, the amount of the carbon fiber necessary for obtaining a predetermined surface resistivity is excessively increased, so that it is difficult to combine the carbon fiber and the resin. is there. In addition, when the fiber length of the carbon fiber is less than 0.1 mm, there is a possibility that the variation in the surface resistivity may be increased, and it may cause dust generation. The fiber length of the carbon fiber is preferably 0.1 mm or more, and more preferably 0.2 mm or more.

  The fiber length of the carbon fiber has a distribution, but it is preferred that it is not too wide. For example, as described in JP-A-7-126434, if a blend of carbon fibers having two lengths is used, the distribution becomes too wide to solve any of the above-mentioned problems. May be difficult. Therefore, the Cv value (variation rate) of the fiber length of the carbon fiber used in the present invention is preferably 100% or less, and more preferably 75% or less. Here, the Cv value (%) is a value obtained by multiplying the value obtained by dividing the standard deviation of the obtained fiber length value by the average value by 100, and is a parameter representing the distribution state. A smaller value indicates a sharper fiber length distribution.

As such carbon fiber, either pitch-based carbon fiber or PAN-based carbon fiber can be used, but pitch-based carbon fiber is more preferable because it can easily adjust the volume resistivity. Among these, pitch-based isotropic carbon fibers are suitable for obtaining a volume resistivity of 10 ⁻¹ to 10 ³ Ω · cm. The production method for obtaining the carbon fiber having the volume resistivity is not particularly limited, but, for example, the progress of carbonization is made incomplete by setting the firing temperature when producing a normal carbon fiber to be low. Can be manufactured by. As a specific firing temperature in this case, a temperature of about 700 to 800 ° C. can be adopted. After firing, the carbon fibers are cut to produce carbon fibers that are blended into the resin composition of the present invention. As a specific cutting method, a method of pulverizing with a mill is suitably employed. In order to reduce the amount of degassing from the molded product, it is preferable to use carbon fibers to which no sizing agent is attached.

  The resin composition constituting the molded article of the present invention comprises 60 to 80% by weight of the cyclic olefin polymer and 20 to 40% by weight of the carbon fiber. When the content of the carbon fiber is less than 20 parts by weight, in the resin composition, the number of contact points between the carbon fibers decreases, and it is difficult to suppress the variation in surface resistivity in the molded product, The absolute value of the surface resistivity is too large. The blending amount of the carbon fiber is preferably 24% by weight or more, and more preferably 28% by weight or more. At this time, the content of the cyclic olefin polymer is preferably 76% by weight or less, and more preferably 72% by weight or less. On the other hand, when the blending amount of the carbon fiber exceeds 40% by weight, it is difficult to combine the carbon fiber and the resin, the fluidity of the resin is significantly lowered, the moldability is deteriorated, and dust generation is likely to occur. . The blending amount of the carbon fiber is preferably 37% by weight or less, and more preferably 35% by weight or less. Thus, by blending a relatively large amount of carbon fiber, it is possible to obtain a molded product in which variation in surface resistivity is suppressed.

  In the resin composition constituting the molded article of the present invention, various additives such as a stabilizer and a lubricant can be added and used within a range not impairing the object of the present invention. However, since it is not preferable to add a component that causes dust generation or a component that causes generation of cracked gas, the type and amount of the additive should be carefully determined.

  The blending method of the cyclic olefin polymer and the carbon fiber is not particularly limited, but can be melt-kneaded by various kneaders such as a single screw extruder, a twin screw extruder, a roll, a Banbury mixer and the like. The resin composition thus melt-kneaded may be subjected to molding as it is, or may be once pelletized and then subjected to melt molding.

  The MFR of the resin composition constituting the molded article of the present invention is preferably 0.2 to 10 g / 10 min. This MFR is measured at 240 ° C. under a load of 2.16 kg based on ASTM D1238, and usually does not change greatly before and after injection molding. When the MFR is less than 0.2 g / 10 minutes, the moldability is deteriorated and a large shearing force is generated at the time of injection molding, which may cause decomposition of the resin. MFR is more preferably 0.5 g / 10 min or more. On the other hand, if the MFR exceeds 10 g / 10 min, the strength of the molded product may be insufficient, and dust generation due to friction or impact may be likely to occur. The MFR is more preferably 5 g / 10 min or less, and even more preferably 2 g / 10 min or less.

  Using the resin composition thus obtained, the molded product for the clean room of the present invention is melt-molded. The molding method is not particularly limited, but injection molding is preferred. In injection molding, the molding conditions can be devised as follows in order to obtain a molded product with little variation in surface resistivity, good appearance, and excellent dimensional accuracy while suppressing decomposition of the resin. preferable.

In the injection molding, it is preferable that the cylinder set temperature (Ts) at the time of injection molding and the deflection temperature under load (Td) of the raw material cyclic olefin polymer satisfy the following formula (1).
Td + 140 ≦ Ts ≦ Td + 200 (1)
If the set temperature of the cylinder is too low, the moldability may be deteriorated, such as incomplete filling of the resin to the complicated part or fine part, or deterioration of the surface condition of the molded product. . In addition, when the cylinder set temperature is too high, the resin may be thermally decomposed to increase the amount of degassing from the molded product, and the strength of the molded product may be reduced due to thermal decomposition of the resin. It is more preferable to satisfy the following formula (1 ′), and it is more preferable to satisfy the following formula (1 ″).
Td + 150 ≦ Ts ≦ Td + 195 (1 ′)
Td + 160 ≦ Ts ≦ Td + 190 (1 ″)

  If the shear rate when the resin composition flows through the nozzle, gate, runner or mold is too large, the resin may decompose due to shear heat generation, and the molded product may generate odor. In addition, when the shape of the mold is complicated, the gas pressure generated by the decomposition of the resin increases the gas pressure inside the mold, and the flow of the resin is hindered and the filling may be insufficient. In addition, the carbon fiber may be cut to shorten the fiber length, which may reduce the antistatic performance. Therefore, it is desirable to send out the resin composition at such a speed that the shear rate does not become too high. Specifically, the injection speed is preferably 20 to 200 ml / sec. The injection speed here is the speed (ml / sec) of the resin composition delivered from the nozzle in the injection molding machine, that is, the delivery amount of the resin composition per unit time. Usually, in an injection molding machine, the screw injection setting speed is often controlled, but the value obtained by multiplying the screw injection setting speed by the cross-sectional area of the screw is grasped as the speed at which the resin composition is actually delivered. . In order to efficiently prevent excessive shearing heat generation, the injection speed is more preferably 150 ml / sec or less, and even more preferably 100 ml / sec or less. On the other hand, if the injection speed is too low, the productivity is lowered, and there is a possibility that the resin is incompletely filled into a complicated part or a fine part, and more preferably 50 ml / sec or more.

Further, it is also preferable that the mold temperature (Tm) and the deflection temperature under load (Td) of the raw material cyclic olefin polymer satisfy the following formula (2).
Td−40 ≦ Tm ≦ Td + 10 (2)
If the mold temperature is too low, the surface state of the molded product tends to deteriorate, and conversely if the mold temperature is too high, the dimensional accuracy of the molded product tends to decrease. It is more preferable to satisfy the following formula (2 ′), and it is more preferable to satisfy the following formula (2 ″).
Td-30 ≦ Tm ≦ Td (2 ′)
Td-20 ≦ Tm ≦ Td-5 (2 ″)

The thus obtained molded product for a clean room of the present invention preferably has a surface resistivity of 10 ⁵ to 10 ¹² Ω / □. By providing the surface resistivity in such a range, it is possible to suppress both ESD and ESA, provide a molded product for a clean room having a surface resistivity in a range in which the charge transfer speed is low and the surface is not charged. be able to. The surface resistivity is more preferably 10 ⁷ Ω / □ or more, and further preferably 10 ⁸ Ω / □ or more. Further, it is more preferably 10 ¹¹ Ω / □ or less. Moreover, it is more preferable to show the surface resistivity in the above range at all the measurable sites on the surface.

  In the molded product of the present invention, it is preferable that the ratio between the maximum value and the minimum value is 100 or less when the surface resistivity is measured at a plurality of positions of the molded product. That is, it is preferable to show the same surface resistivity at various locations of the molded product. In particular, a molded product having a large dimension or a molded product having a complicated shape can have such a uniform surface resistivity, so that there is a great advantage in using the resin composition having the structure of the present invention. The ratio is more preferably 20 or less, and further preferably 10 or less.

  The molded product of the present invention preferably has a total degassing amount of 10 μg / g or less in terms of hexadecane when heated at 150 ° C. for 30 minutes. By setting the degas amount to be small in this way, it is possible to prevent contamination of intermediate products or products such as silicon wafers in the semiconductor manufacturing process, glass substrates in the liquid crystal panel manufacturing process, and metal disks in the hard disk manufacturing process. The total degassing amount is more preferably 5 μg / g or less.

  The molded product for the clean room of the present invention is not particularly limited as long as it is a molded product used in the clean room. In the clean room, containers, trays, jigs and tools for handling raw materials, intermediate products or products are exemplified. As a preferred embodiment, a container in which a plate-like body selected from a semiconductor substrate, a display substrate, and a recording medium substrate is stored is exemplified. The plate-like body here includes not only a large-sized one but also a chip obtained by cutting it. Among the plate-like bodies, a container for a semiconductor substrate and a display substrate, which is highly likely to cause ESD destruction, is a preferred embodiment. In particular, a semiconductor substrate container with a strict management level is the most preferred embodiment. Another preferred embodiment is a tool for handling raw materials, intermediate products or finished products. Since such jigs and tools often come into direct contact with raw materials, intermediate products or finished products, the benefits of applying the molded product of the present invention are great. Examples of such jigs and tools include tweezers. What is handled by the jig is not particularly limited, and various forms such as plates, blocks, and containers can be handled. Among these, a jig for handling a plate-like body selected from a semiconductor substrate, a display substrate, and a recording medium substrate is preferable. A jig for handling a semiconductor substrate and a display substrate that are highly likely to cause ESD destruction is more suitable, and a jig for handling a semiconductor substrate with a strict management level is most preferred.

  Examples of the semiconductor substrate include a substrate for manufacturing an integrated circuit and a substrate for manufacturing a solar cell. The material is represented by silicon, but is not particularly limited. Moreover, the shape may be a circle like a silicon wafer, or may be a rectangle like a solar battery cell. Moreover, the form of the chip | tip which cut | disconnected the silicon wafer may be sufficient.

  Among them, a typical embodiment is a container for silicon wafers. The clean room container of the present invention, which maintains the surface resistivity within a suitable range and reduces outgassing and dust generation, is suitable for storing silicon wafers. In recent years, the diameter of silicon wafers has been increasing, and the dimensions of silicon wafer containers have increased accordingly. Therefore, since the required level of dimensional accuracy of the entire molded product becomes stricter as the size increases, the clean room container of the present invention that can be molded with high dimensional accuracy is suitable.

  At this time, in the case of a container called a carrier in which silicon wafers are directly arranged, the silicon wafer directly contacts the carrier, so that ESD damage is particularly likely to be a problem, and cross-contamination via a processing solution or the like is likely to occur. Nation is likely to occur. Therefore, it is preferable to use the molded product for the clean room of the present invention for such a carrier. The molded product for the clean room of the present invention is also suitably used for a container called a case or a box in which the carrier is housed, or an integrated container that simultaneously serves as a carrier and a case. The

  Examples of the display substrate include a substrate for manufacturing a liquid crystal display, a substrate for manufacturing a plasma display, and a substrate for manufacturing an electroluminescence (EL) display. The material of these substrates is typically glass, but other materials such as a transparent resin may be used. Also in the case of these display substrates, since there is a pixel driving circuit and ESD damage becomes a problem, it is preferable to employ the molded product for the clean room of the present invention. Moreover, since many display substrates are particularly large, it is preferable to use the molded product for the clean room of the present invention having excellent dimensional accuracy.

  Moreover, examples of the recording medium substrate include a hard disk substrate and an optical disk substrate. The material for the hard disk substrate is typically metal or glass, but is not limited thereto. The material for the optical disk substrate is typically a transparent plastic represented by polycarbonate, but is not limited thereto. For these recording media, the composition of the recording film differs depending on the recording format, but in recent years, due to the dramatic improvement in recording density, the influence of a small amount of contaminants on the performance has increased, and the clean room of the present invention A molded article is preferably used.

  Hereinafter, the present invention will be described in more detail using examples.

Example 1
“Apel 6011T” manufactured by Mitsui Chemicals, Inc. was used as the cyclic olefin polymer (CPO). The load deflection temperature (ASTM D648) at a stress of 1.82 MPa of the cyclic olefin polymer is 95 ° C., and the MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg is 11.6 g / 10 min. .

As the carbon fiber, Donac Co., Ltd. pitch-based isotropic carbon fiber “Donna Carbo (registered trademark) SL-242” was used. The carbon fiber is produced by vortex spinning, and is produced by pulverizing the obtained raw yarn with a mill without using a sizing agent. The carbon fiber has a diameter of 13 μm, a fiber length of 0.37 mm, and a volume resistivity of 10 ² Ω · cm. The fiber length of the carbon fiber is a length of 200 or more fibers using an image analyzer “XL500” manufactured by Olympus Kogyo Co., Ltd. in a 50 × image observed using an optical microscope “SZH” manufactured by Olympus Kogyo Co., Ltd. Is obtained as a weighted weighted average length. The Cv value (variation rate) of the fiber length is about 60%. Here, the Cv value (%) is a value obtained by multiplying the value obtained by dividing the standard deviation by the average value by 100.

  68 parts by weight of the cyclic olefin polymer and 32 parts by weight of the carbon fiber were melt-kneaded using a twin screw extruder (manufactured by Plastic Engineering Laboratory Co., Ltd., screw diameter 32 mm, L / D = 33). Carbon fiber was added from the vent port using a gravimetric feeder and melt extruded at 230 ° C. to obtain a strand. The strand was cut with a pelletizer to obtain a resin composition pellet. The MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg was 1.1 g / 10 min.

  This resin composition pellet is supplied to an injection molding machine “Nestal P204 / 100” manufactured by Sumitomo Heavy Industries, Ltd., molded under the conditions of a resin temperature of 240 ° C., a mold temperature of 100 ° C., and a clamping pressure of 100 t, and a diameter of 50 mm. A disc-shaped test piece having a thickness of 3 mm and a rectangular parallelepiped test piece having a length of 125 mm, a width of 13 mm, and a thickness of 3 mm were obtained.

About five disk-shaped test pieces obtained in this way, surface resistivity was measured at an applied voltage of 100 V according to ASTM D257, using a high resistance measuring instrument “R8340” manufactured by Advantest Corporation. As a result, the maximum value was 2 × 10 ¹⁰ Ω / □, the minimum value was 3 × 10 ⁹ Ω / □, and the average value was 7 × 10 ⁹ Ω / □. Moreover, when the shrinkage rate was calculated based on the mold dimensions using a caliper for the rectangular test piece in the vertical direction (TD) and the flow direction (MD), the TD was 0.5% and the MD was 0.1%. there were. A part of the disk-shaped test piece was cut out with a cutter blade, dissolved in cyclohexane, and the carbon fiber was separated by filtration. About the obtained carbon fiber, it observed with the optical microscope similarly to the said method, and it was 0.25 mm when the average length was measured using the image-analysis apparatus. The evaluation results are summarized in Table 1.

Example 2
“Apel 6509T” manufactured by Mitsui Chemicals, Inc. was used as the cyclic olefin polymer. The load deflection temperature (ASTM D648) of the cyclic olefin polymer at a stress of 1.82 MPa is 70 ° C., and the MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg is 14.9 g / 10 min. . As a carbon fiber, a pitch-type isotropic carbon fiber “Donna Carbo (registered trademark) SL-242” manufactured by Donac Co., Ltd. was used in the same manner as in Example 1.

  Using the same twin-screw extruder as in Example 1, 68 parts by weight of the cyclic olefin polymer and 32 parts by weight of the carbon fiber were melt-kneaded. Carbon fiber was added from the vent port using a gravimetric feeder and melt extruded at 210 ° C. to obtain a strand. The strand was cut with a pelletizer to obtain a resin composition pellet. The MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg was 1.5 g / 10 minutes. The pellets are supplied to the same injection molding machine as in Example 1 and molded under the conditions of a resin temperature of 230 ° C., a mold temperature of 80 ° C., and a clamping pressure of 100 t, and the same disk-shaped test piece and cuboid as in Example 1 The test piece was obtained.

The surface resistivity of the five disk-shaped test pieces thus obtained was measured in the same manner as in Example 1. The maximum value was 2 × 10 ¹⁰ Ω / □, the minimum value was 6 × 10 ⁹ Ω / □, and the average value. Was 9 × 10 ⁹ Ω / □. Moreover, when the shrinkage | contraction rate was computed similarly to Example 1 about the vertical direction (TD) and the flow direction (MD) about the test piece of a rectangular parallelepiped, TD was 0.6% and MD was 0.1%. Moreover, when the fiber length of the carbon fiber in a test piece was measured similarly to Example 1, it was 0.27 mm. The evaluation results are summarized in Table 1.

Example 3
“Zeonor 1020R” manufactured by Nippon Zeon Co., Ltd. was used as the cyclic olefin polymer. The load deflection temperature (ASTM D648) at a stress of 1.82 MPa of the cyclic olefin polymer is 101 ° C., and the MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg is 2.7 g / 10 minutes. . As a carbon fiber, a pitch-type isotropic carbon fiber “Donna Carbo (registered trademark) SL-242” manufactured by Donac Co., Ltd. was used in the same manner as in Example 1.

  Using the same twin-screw extruder as in Example 1, 68 parts by weight of the cyclic olefin polymer and 32 parts by weight of the carbon fiber were melt-kneaded. Carbon fiber was added from the vent port using a gravimetric feeder and melt extruded at 230 ° C. to obtain a strand. The strand was cut with a pelletizer to obtain a resin composition pellet. The MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg was 1.0 g / 10 min. The pellets are supplied to the same injection molding machine as in Example 1 and molded under the conditions of a resin temperature of 255 ° C., a mold temperature of 100 ° C., and a clamping pressure of 100 t, and the same disk-shaped test piece and cuboid as in Example 1 The test piece was obtained.

When the surface resistivity of the five disk-shaped test pieces thus obtained was measured in the same manner as in Example 1, the maximum value was 3 × 10 ⁹ Ω / □, the minimum value was 8 × 10 ⁸ Ω / □, and the average value. Was 1 × 10 ⁹ Ω / □. Moreover, when the shrinkage | contraction rate was computed similarly to Example 1 about the perpendicular direction (TD) and the flow direction (MD) about the rectangular test piece, TD was 0.4% and MD was 0.1%. Moreover, when the fiber length of the carbon fiber in a test piece was measured similarly to Example 1, it was 0.23 mm. The evaluation results are summarized in Table 1.

Example 4
As a cyclic olefin polymer, “ZEONOR 1420R” manufactured by Nippon Zeon Co., Ltd. was used. The load deflection temperature (ASTM D648) of the cyclic olefin polymer at a stress of 1.82 MPa is 136 ° C., and MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg is 2.4 g / 10 minutes. . As a carbon fiber, a pitch-type isotropic carbon fiber “Donna Carbo (registered trademark) SL-242” manufactured by Donac Co., Ltd. was used in the same manner as in Example 1.

  Using the same twin-screw extruder as in Example 1, 68 parts by weight of the cyclic olefin polymer and 32 parts by weight of the carbon fiber were melt-kneaded. Carbon fiber was added from the vent port using a gravimetric feeder and melt extruded at 260 ° C. to obtain a strand. The strand was cut with a pelletizer to obtain a resin composition pellet. The MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg was 0.9 g / 10 min. The pellets are supplied to the same injection molding machine as in Example 1 and molded under the conditions of a resin temperature of 285 ° C., a mold temperature of 100 ° C., and a clamping pressure of 100 t, and the same disk-shaped test piece and cuboid as in Example 1 The test piece was obtained.

When the surface resistivity of the five disk-shaped test pieces thus obtained was measured in the same manner as in Example 1, the maximum value was 1 × 10 ¹⁰ Ω / □, the minimum value was 3 × 10 ⁹ Ω / □, and the average value. Was 7 × 10 ⁹ Ω / □. Moreover, when the shrinkage | contraction rate was computed similarly to Example 1 about the perpendicular direction (TD) and the flow direction (MD) about the rectangular test piece, TD was 0.7% and MD was 0.2%. Moreover, when the fiber length of the carbon fiber in a test piece was measured similarly to Example 1, it was 0.22 mm. The evaluation results are summarized in Table 1.

Comparative Example 1
As a cyclic olefin polymer, “Apel 6011T” manufactured by Mitsui Chemicals, Inc. was used in the same manner as in Example 1. As the carbon fiber, Donac Co., Ltd. pitch-based isotropic carbon fiber “Donacarbo (registered trademark) S-242” was used. The carbon fiber has a diameter of 13 μm, a fiber length of 0.37 mm, and a volume resistivity of 10 ⁻² Ω · cm. The fiber length of the carbon fiber was determined in the same manner as in Example 1.

68 parts by weight of the cyclic olefin polymer and 32 parts by weight of the carbon fiber were melt-kneaded in the same manner as in Example 1 to obtain resin composition pellets. The MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg was 1.0 g / 10 min. This pellet was injection-molded in the same manner as in Example 1 to obtain a disk-shaped test piece and a rectangular parallelepiped test piece. When the surface resistivity of the five disk-shaped test pieces thus obtained was measured in the same manner as in Example 1, the maximum value was 2 × 10 ⁵ Ω / □, the minimum value was 4 × 10 ⁴ Ω / □, and the average value. Was 9 × 10 ⁴ Ω / □. Moreover, when the fiber length of the carbon fiber in a test piece was measured similarly to Example 1, it was 0.25 mm. The evaluation results are summarized in Table 1.

Comparative Example 2
As a cyclic olefin polymer, “Apel 6011T” manufactured by Mitsui Chemicals, Inc. was used in the same manner as in Example 1. As the carbon fiber, Donac Co., Ltd. pitch-based isotropic carbon fiber “DonaCarbo (registered trademark) S-244” was used. The carbon fiber has a diameter of 13 μm, a fiber length of 0.7 mm, and a volume resistivity of 10 ⁻² Ω · cm. The fiber length of the carbon fiber was determined in the same manner as in Example 1.

82 parts by weight of the cyclic olefin polymer and 18 parts by weight of the carbon fibers were melt-kneaded in the same manner as in Example 1 to obtain resin composition pellets. The MFR (ASTM D1238) at a temperature of 240 ° C. and a load of 2.16 kg was 1.9 g / 10 min. This pellet was injection-molded in the same manner as in Example 1 to obtain a disk-shaped test piece and a rectangular parallelepiped test piece. The surface resistivity was measured in the same manner as in Example 1 for the five disk-shaped test pieces thus obtained. The surface resistivity of the five test pieces is insulation (> 10 ¹⁵ Ω / □), 1 × 10 ¹¹ Ω / □, 2 × 10 ⁸ Ω / □, 5 × 10 ⁸ Ω / □ and 1 × 10, respectively. It was ⁵ Ω / □. Moreover, when the fiber length of the carbon fiber in a test piece was measured similarly to Example 1, it was 0.31 mm. The evaluation results are summarized in Table 1.

Comparative Example 3
As a material used for molding, a resin composition pellet “PDX-W-02840” manufactured by LNP Engineering Plastics was used. The said pellet is a pellet which consists of a resin composition which carbon fiber was mix | blended with the polybutylene terephthalate and the electroconductivity was provided, and is marketed. The resin composition pellets are supplied to the same injection molding machine as in Example 1 and molded under the conditions of a resin temperature of 230 ° C., a mold temperature of 70 ° C., and a clamping pressure of 100 t. The same rectangular parallelepiped test piece as in Example 1 Got. When the shrinkage was calculated in the same manner as in Example 1 in the vertical direction (TD) and the flow direction (MD) for the cuboid test piece thus obtained, the TD was 3.9% and the MD was 0.4%. It was. The evaluation results are summarized in Table 1.

As shown in Table 1, the molded articles of the present invention obtained in Examples 1 to 4 have a surface resistivity in the range of 10 ⁸ to 10 ¹¹ Ω / □. Moreover, in these molded products, the maximum value of the surface resistivity is less than 10 times the minimum value, and it can be seen that there is little variation between the molded products. That is, it is possible to show an appropriate surface resistivity value with good reproducibility. On the other hand, when the carbon fiber having a volume resistivity value smaller than 10 ⁻¹ Ω · cm is used as in Comparative Example 1, the surface resistivity of the molded product is less than 10 ⁵ Ω / □. End up. If a small amount of carbon fiber having a volume specific resistance value smaller than 10 ⁻¹ Ω · cm is blended as in Comparative Example 2, the variation in the value of the surface resistivity between the molded products becomes large. In addition, the molded products of the present invention obtained in Examples 1 to 4 have a smaller shrinkage rate and excellent dimensional accuracy than the molded product of Comparative Example 3 using PBT.

Example 5
The resin composition pellet produced in Example 1 was supplied to an injection molding machine “ROBOSHOT α-150iA” manufactured by FANUC CORPORATION to obtain a disk-shaped test piece having a diameter of 150 mm and a thickness of 3 mm. The diameter of the screw of the injection molding machine is 44 mm. The molding conditions are as follows.
・ Cylinder set temperature: 270 ℃
・ Mold set temperature: 80 ℃
-Screw injection setting speed: 50mm / sec
(Injection speed of resin composition: 76 ml / sec)
・ Injection set pressure: 200 MPa
About the obtained test piece, surface condition and odor sensory evaluation were evaluated according to the method shown below. The results are summarized in Table 2.

(1) Surface state The appearance of the molded product obtained by injection molding was visually evaluated by five test panelists. The score was based on the following criteria:
4 points: Fiber orientation is not confirmed. The surface is glossy.
3 points: Fiber orientation is confirmed, but the surface is not glossy.
2 points: Fiber orientation is clearly confirmed, but there is no surface roughness.
1 point: The fiber orientation is clearly confirmed, and the surface is rough.

(2) Odor The molded product obtained by injection molding was allowed to stand at room temperature for 24 hours, then sealed in a polyethylene bag and left at room temperature for 24 hours. After that, five odor-sensitive test panelers opened the sealed bags, sniffed the odor level, and performed a sensory evaluation of the odor. The score was based on the following criteria:
5 points: No smell is felt.
4 points: A slight odor is felt.
3 points: I feel a smell.
2 points: I feel quite smelly.
1 point: A strong smell is clearly felt.

Examples 6 and 7
A disc-shaped test piece was obtained in the same manner as in Example 5 except that the cylinder set temperature was changed to 230 ° C. (Example 6) and 250 ° C. (Example 7). About the obtained test piece, the surface state and odor were evaluated according to the said method. The results are summarized in Table 2.

Examples 8 and 9
A disc-shaped test piece was obtained in the same manner as in Example 5 except that the injection setting speed of the screw was changed to 100 mm / sec (Example 8) and 150 mm / sec (Example 9). The injection speed of the resin composition at this time was 152 ml / sec (Example 8) and 228 ml / sec (Example 9), respectively. About the obtained test piece, the surface state and odor were evaluated according to the said method. The results are summarized in Table 2.

Example 10
The resin composition pellet produced in Example 2 was supplied to an injection molding machine “ROBOSHOT α-150iA” manufactured by FANUC CORPORATION to obtain a disk-shaped test piece having a diameter of 150 mm and a thickness of 3 mm. The diameter of the screw of the injection molding machine is 44 mm. The molding conditions are as follows.
・ Cylinder set temperature: 240 ℃
・ Mold setting temperature: 60 ℃
-Screw injection setting speed: 50mm / sec
(Injection speed of resin composition: 76 ml / sec)
・ Injection set pressure: 200 MPa
About the obtained test piece, surface condition and odor sensory evaluation were evaluated according to the said method. The results are summarized in Table 2.

Examples 11 and 12
A disc-shaped test piece was obtained in the same manner as in Example 10 except that the cylinder set temperature was changed to 200 ° C. (Example 11) and 220 ° C. (Example 12). About the obtained test piece, the surface state and odor were evaluated according to the said method. The results are summarized in Table 2.

Examples 13 and 14
A disc-shaped test piece was obtained in the same manner as in Example 10, except that the screw injection setting speed was changed to 100 mm / sec (Example 13) and 150 mm / sec (Example 14). The injection speed of the resin composition at this time was 152 ml / sec (Example 13) and 228 ml / sec (Example 14), respectively. About the obtained test piece, the surface state and odor were evaluated according to the said method. The results are summarized in Table 2.

  As can be seen by comparing Examples 5 to 7, the surface condition of the molded product is better when the cylinder set temperature is higher. This also applies to Examples 10 to 12. Further, as can be seen from a comparison of Examples 5, 8 and 9, it can be seen that if the injection speed is too high, odor is likely to be generated. This also applies to the tenth, thirteenth and fourteenth embodiments. That is, it is preferable to mold at a low injection speed while maintaining a high cylinder set temperature within a range not causing thermal decomposition of the resin. Moreover, when the deflection temperature under load of the raw material cyclic olefin polymer is high, it is preferable to increase the cylinder set temperature and the mold temperature.

Example 15
The same resin composition pellets used in Example 1 were supplied to an injection molding machine “J450E-C5” manufactured by Nippon Steel Works, Ltd., and the 150 mm wafer carrier shown in FIGS. The diameter of the screw of the injection molding machine is 76 mm. The molding conditions are as follows.
・ Cylinder set temperature: 290 ℃
・ Mold set temperature: 80 ℃
-Screw injection setting speed: 20mm / sec
(Injection speed of resin composition: 91 ml / sec)
・ Injection set pressure: 200 MPa
About the obtained test piece, each evaluation of dimensional accuracy, surface resistivity, degassing total amount, and dust generation amount was performed according to the method shown below. The results are summarized in Table 3.

(3) Dimensional accuracy The molded product obtained by injection molding was allowed to stand at room temperature for 24 hours, and then conditioned at 23 ° C. and humidity of 50% RH for 6 hours or more. About the molded article after state adjustment, the dimension (mm) of the site | part shown in FIG. 3 was measured with the image processing test | inspection apparatus. As an inspection apparatus, an automatic wafer carrier visual inspection apparatus “CV-9800 type” manufactured by August Technology was used. The said dimension was measured about five molded articles, the absolute value of the difference of each of five measured values and those average values was calculated | required, and the average value of the absolute value was calculated | required as dimension variation (mm).

(4) Surface resistivity The molded product obtained by injection molding was allowed to stand at room temperature for 24 hours and then conditioned at 23 ° C. and humidity of 50% RH for 6 hours or more. About the molded article after the condition adjustment, the surface resistivity (Ω / □) of 8 parts shown in FIGS. 4 and 5 is applied with 100 V by a resistance meter “SUPER MEGOHMMETER SM-21E” manufactured by Toa Denpa Kogyo Co., Ltd. Measured by applying voltage. At this time, 10 mm square conductive rubber having a thickness of 2 mm was disposed between the positive and negative terminals and the surface of the molded product, and the distance between the conductive rubbers was 10 mm. The resistance value of the conductive rubber used here is much smaller than the molded product to be evaluated, and the resistance value derived therefrom can be ignored.

(5) Total amount of degassing About 0.1 g of a sample obtained by cutting a molded product obtained by injection molding into a strip shape is weighed, put into a test tube, and the gas generated when heated at 150 ° C. for 30 minutes is −40 After collecting at ° C., the total amount of degassing was determined by online injection into the gas chromatograph. The total degassing amount was calculated as a hexadecane conversion value. Curry point purge and trap sampler “JHS-100A type” manufactured by Nippon Analytical Industrial Co., Ltd. is used for collecting generated gas, and GC-14A type and QP1100EX type gas chromatographs manufactured by Shimadzu Corporation are used for analysis and quantification. A mass spectrometer (GC / MS analyzer) was used. At this time, a hexadecane solution having a known concentration was measured under the same conditions (150 ° C. for 30 minutes, collected at −40 ° C., GC / MS analysis), and the hexadecane equivalent value of the sample generated gas was calculated based on the obtained peak area. Asked.

(6) Dust generation amount In a Class 2 (JIS B9920 standard) clean room, a sampling tube is set near the tooth on the wafer insertion side, and a load of about 25 to 30 g is applied with a non-dust generation stick from the outside of the carrier. Shock was given at the timing of times / minute. The number of dust particles of 0.1 to 1.0 μm generated at that time was measured with a laser particle counter “MetOne model A2100B” manufactured by Hach Ultra Analytics. The measurement was repeated 5 times, and the average value was obtained.

Example 16
A 150 mm wafer carrier was molded in the same manner as in Example 15 except that the same resin composition pellets used in Example 2 were used and the molding conditions were changed as follows.
・ Cylinder set temperature: 240 ℃
・ Mold setting temperature: 60 ℃
-Screw injection setting speed: 20mm / sec
(Injection speed of resin composition: 91 ml / sec)
・ Injection set pressure: 200 MPa
About the obtained test piece, each evaluation of dimensional accuracy, surface resistivity, degassing total amount, and dust generation amount was performed according to the said method. The results are summarized in Table 3.

Example 17
A 150 mm wafer carrier was molded in the same manner as in Example 15 except that the same resin composition pellets used in Example 3 were used and the molding conditions were changed as follows.
・ Cylinder set temperature: 260 ℃
・ Mold setting temperature: 60 ℃
-Screw injection setting speed: 20mm / sec
(Injection speed of resin composition: 91 ml / sec)
・ Injection set pressure: 200 MPa
About the obtained test piece, each evaluation of dimensional accuracy, surface resistivity, degassing total amount, and dust generation amount was performed according to the said method. The results are summarized in Table 3.

Comparative Example 4
A 150 mm wafer carrier was molded in the same manner as in Example 15 except that persistent antistatic polypropylene (PP) pellets ("ECX T-396NA" manufactured by Mitsubishi Chemical Corporation) were used as materials and the molding conditions were changed as follows. did. The pellet is obtained by blending polypropylene with an antistatic agent made of a hydrophilic polymer.
・ Cylinder setting temperature: 210 ℃
・ Mold setting temperature: 50 ℃
-Screw injection setting speed: 20mm / sec
(Injection speed of resin composition: 91 ml / sec)
・ Injection set pressure: 200 MPa
About the obtained test piece, each evaluation of dimensional accuracy, surface resistivity, degassing total amount, and dust generation amount was performed according to the said method. The results are summarized in Table 3.

Comparative Example 5
A 150 mm wafer carrier was molded in the same manner as in Example 15 except that a long-lasting antistatic polybutylene terephthalate (PBT) pellet ("CA7200NX" manufactured by Wintech Polymer Co., Ltd.) was used as a material and the molding conditions were changed as follows. did. The pellet is obtained by blending an antistatic agent made of a hydrophilic polymer with polybutylene terephthalate.
・ Cylinder set temperature: 240 ℃
・ Mold setting temperature: 50 ℃
-Screw injection setting speed: 20mm / sec
(Injection speed of resin composition: 91 ml / sec)
・ Injection set pressure: 200 MPa
About the obtained test piece, each evaluation of dimensional accuracy, surface resistivity, degassing total amount, and dust generation amount was performed according to the said method. The results are summarized in Table 3.

Comparative Example 6
85 parts by weight of polybutylene terephthalate resin pellets “Toraycon 1401-X06” manufactured by Toray Industries, Inc. and 15 parts by weight of Ketjen Black “Ketjen Black EC” manufactured by Lion Co., Ltd. And melt kneading using a screw diameter of 32 mm and L / D = 33). Ketjen black was added from the vent port using a gravimetric feeder and melt extruded at 230 ° C. to obtain a strand. The strands were cut with a pelletizer to obtain pellets.

A 150 mm wafer carrier was molded in the same manner as in Example 15 except that the obtained pellets were used as materials and the molding conditions were changed as follows.
・ Cylinder set temperature: 280 ℃
・ Mold set temperature: 80 ℃
-Screw injection setting speed: 20mm / sec
(Injection speed of resin composition: 91 ml / sec)
・ Injection set pressure: 200 MPa
About the obtained test piece, each evaluation of dimensional accuracy, surface resistivity, degassing total amount, and dust generation amount was performed according to the said method. The results are summarized in Table 3.

Comparative Example 7
A 150 mm wafer carrier in the same manner as in Example 15 except that a long-lasting antistatic polyetheretherketone (PEEK) pellet (“KNE5010” manufactured by Victorex MC Corporation) was used as a material and the molding conditions were changed as follows. Was molded. The pellet is obtained by blending conductive carbon powder with polyetheretherketone.
・ Cylinder set temperature: 420 ℃
・ Mold setting temperature: 180 ℃
-Screw injection setting speed: 20mm / sec
(Injection speed of resin composition: 91 ml / sec)
・ Injection set pressure: 200 MPa
About the obtained test piece, each evaluation of dimensional accuracy, surface resistivity, degassing total amount, and dust generation amount was performed according to the said method. The results are summarized in Table 3.

As shown in Examples 15 to 17, the molded product of the present invention is excellent in dimensional accuracy, exhibits a surface resistivity in the range of 10 ⁸ to 10 ¹⁰ Ω / □ at any part of the molded product, and is degassed. The total amount is small and the amount of dust generation is also small. On the other hand, when the commercially available antistatic resin compositions as shown in Comparative Examples 4 to 7 are used, there are the following problems. That is, as in Comparative Example 4, when a polypropylene blended with an antistatic agent made of a hydrophilic polymer is used, the dimensional variation is large and the total degassing amount is large. Even when a polybutylene terephthalate blended with an antistatic agent composed of a hydrophilic polymer is used as in Comparative Example 5, both the dimensional variation and the total degassing amount are inferior to those of the Examples. As in Comparative Example 6, when a polybutylene terephthalate blended with carbon powder is used, the generation of dust depending on the dispersion state of the carbon powder becomes significant, and the variation in surface resistivity also increases. When using a mixture of polyether ether ketone and carbon powder as in Comparative Example 7, the dimensional accuracy derived from the resin characteristics and the total degassing amount are good, but depend on the dispersion state of the carbon powder. The surface resistivity is low, and the amount of dust generation increases. The distribution of surface resistivity is summarized in FIG.

It is a front view of the wafer carrier shape | molded in Examples 15-17 and Comparative Examples 4-7. It is a rear view of the wafer carrier shape | molded in Examples 15-17 and Comparative Examples 4-7. It is a top view of the wafer carrier shape | molded in Examples 15-17 and Comparative Examples 4-7. It is a measurement site | part of the surface resistivity of the wafer carrier shape | molded in Examples 15-17 and Comparative Examples 4-7. It is a measurement site | part of the surface resistivity of the wafer carrier shape | molded in Examples 15-17 and Comparative Examples 4-7. It is a graph of the distribution condition of the surface resistivity measured in Examples 15-17 and Comparative Examples 4-7.

Claims (13)

60 to 80% by weight of cyclic olefin polymer, 20 to 40% by weight of carbon fiber having a volume resistivity of 10 ⁻¹ to 10 ³ Ω · cm, a fiber diameter of 5 to 30 μm, and a fiber length of 0.1 to 1 mm. A molded product for a clean room made of a resin composition comprising 1%. The molded product for a clean room according to claim 1, wherein the cyclic olefin polymer has a deflection temperature under load (Td: measured at 1.82 MPa stress based on ASTM D648) of 60 to 150 ° C. The molded product for a clean room according to claim 1 or 2, wherein the carbon fiber is not attached with a sizing agent. The molded product for a clean room according to any one of claims 1 to 3, wherein the resin composition has an MFR (measured at 240 ° C under a load of 2.16 kg based on ASTM D1238) of 0.2 to 10 g / 10 min. The molded product for a clean room according to any one of claims 1 to 4, wherein the surface resistivity is 10 ⁵ to 10 ¹² Ω / □. The clean room molded article according to any one of claims 1 to 5, wherein the ratio of the maximum value to the minimum value when the surface resistivity is measured at a plurality of positions of the molded article is 100 or less. The molded product for a clean room according to any one of claims 1 to 6, wherein the total amount of degassing when heated at 150 ° C for 30 minutes is 10 µg / g or less in terms of hexadecane. The molded product for a clean room according to any one of claims 1 to 7, which is a container in which a plate-like body selected from a semiconductor substrate, a display substrate and a recording medium substrate is stored. The molded product for a clean room according to any one of claims 1 to 7, which is a jig for handling raw materials, intermediate products or finished products. Carbon fiber having a cyclic olefin polymer of 60 to 80% by weight, a volume resistivity of 10 ⁻¹ to 10 ³ Ω · cm, a fiber diameter of 5 to 30 μm, and a fiber length of 0.1 to 1 mm. A method for producing a molded product for a clean room, in which a resin composition obtained by melt-kneading 20 to 40% by weight is injection-molded. The cylinder set temperature (Ts) at the time of injection molding and the deflection temperature under load of the cyclic olefin polymer (Td: measured at 1.82 MPa stress based on ASTM D648) satisfy the following formula (1): Of manufacturing molded products for clean rooms.
Td + 140 ≦ Ts ≦ Td + 200 (1) The method for producing a molded product for a clean room according to claim 10 or 11, wherein the injection speed is 20 to 200 ml / sec. The mold temperature (Tm) and the deflection temperature under load of the cyclic olefin polymer (Td: measured at 1.82 MPa stress based on ASTM D648) satisfy the following formula (2): The manufacturing method of the molded article for the clean room as described.
Td−40 ≦ Tm ≦ Td + 10 (2)

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